The salicylic acid pathway is one of the primary plant defense pathways, is ubiquitous in vascular plants, and plays a role in rapid adaptions to dynamic abiotic and biotic stress. Its prominence and ubiquity make it uniquely suited for understanding how biochemistry within plants can mediate ecological consequences. Induction of the salicylic acid pathway has primary effects on the plant in which it is induced resulting in genetic, metabolomic, and physiologic changes as the plant adapts to challenges. These primary effects can in turn have secondary consequences for herbivores and pathogens attacking the plant. These secondary effects can both directly influence plant attackers and mediate indirect interactions between herbivores and pathogens. Additionally, stimulation of salicylic acid related defenses can affect natural enemies, predators and parasitoids, which can recruit to plant signals with consequences for herbivore populations and plant herbivory aboveground and belowground. These primary, secondary, and tertiary ecological consequences of salicylic acid signaling hold great promise for application in agricultural systems in developing sustainable high-yielding management practices that adapt to changing abiotic and biotic environments. Agricultural productivity is a global priority . With a As a consequence of these genetic improvement efforts, modern cultivars have lost the adaptability  and defeThese direct and indirect defenses are regulated through biochemical pathways that rely on plant hormones to mediate physiological changes that aid in plant defense . These cBecause of these reasons, the SA pathway is the focus of this review. It is important to keep in mind, however, that these systems of plant defense do not occur in isolation. There is ample evidence of cross-talk between plant defense pathways with the JA pathway, for example ,14,15. TKeeping in mind the potential for cross-talk, this review will focus primarily on the ecology of the SA pathway. Much work has been done elucidating the individual steps in synthesis, mechanisms of induction, and biochemical pathways that form the SA pathway. This review will touch on many of those points, but with a focus on how those pathways and reactions effect communication with the plant itself and with other organisms. The ecology of the SA pathway—how the SA pathway in a given plant mediates interactions between and with other organisms—is just beginning to be understood. The goal of this review is to provide a basis for future work that aims to explore this space more fully.To that end, this review will be structured with separate sections focusing on the primary, secondary, and tertiary effects of inducing the SA pathway. The objective of these sections is to highlight primary effects of SA on the plant, the secondary effects of SA on pests and pathogens, and the tertiary effects of SA on natural enemies . In eachSalicylic acid, as a molecule, has remarkable properties in multiple fields . IndepenArabidopsis [Production of salicylic acid occurs in plant plastids where the end product in the shikimic acid pathway, chorismic acid can be further processed into either isochorismic acid or prephenic acid then L-phenylalanine and trans-cinnamic acid . These tbidopsis .Arabidopsis model systems [Arabidopsis or other plant systems [Whether production of salicylic acid by either the ICS or PAL pathways has ecological consequences for induction of the pathway or downstream effects on other organisms remains unclear. Previous work showed that the ICS pathway may be primarily responsible for production of SA , but bot systems ,26. To o systems ,25,26,27Following production of SA, the plant hormone can be modified in several different ways that affects its solubility, mobility, and use as a signal. Among other steps that may occur post-synthesis, SA can be glucosylated, methylated, and conjugated with amino acids ,24,25. GArabidopsis range from 0.250 Regulation of SA is almost universally important for plant physiology, but not universally uniform; plants vary substantially in basal levels of SA ,29. Multg g−1 FW . Within g g−1 FW ,30.Downstream of production, SA can have a multitude of effects on plant physiology in all parts of the plant. SA affects plant thermogenesis, stomatal dynamics, seed germination, cell growth, vegetative growth, flowering, photosynthesis, responses to abiotic stresses and defensive responses against pests and pathogens ,36,37,38In mediating responses to abiotic stress, SA increases the efficiency of the antioxidant system in plants . SA can When plants are attacked by microbes and pathogens, a series of plant defense responses can be triggered. Pattern recognition receptors in the plant can detect pathogen and microbe specific patterns that can, in turn, stimulate pattern triggered immunity (PTI) ,42,43. INPR) [Systemic acquired resistance (SAR), the ability of plants to develop long-term resistance to micro-organisms even in parts of the plant not initially attacked, is a key aspect of plant defense and dependent upon accumulation of SA ,46. SA cNPR) ,49,50,51NPR) ,54,55,56While induction of the SA pathway by pathogens can result in SAR, activation of the SA pathway can be induced exogenously through application of elicitors and plays important roles in regulating responses to other organisms including attack by other plants, and by insect herbivores.Ever since early recognition of SA as a plant signal, exogenous application of SA has been used to induce adaptive responses in plants to both abiotic and biotic stress ,39,57. IStriga infection in Sorghum can elicit hypersensitive responses at sites of attack [Plants attacked by other parasitic plants can exhibit pathogenically similar responses with regulation by SA . Striga f attack . Similarf attack . Dodder f attack . This isf attack .Myzus persicae) on Arabidopsis induces SA related gene expression involved in pathogen defense [Diuraphis noxia Mordvilko) on wheat induces SA accumulation which plays a role in resistance [Bemisia tabaci type B) feeding on Arabidopsis induces the SA related plant defenses while suppressing the JA defense pathway [Given the prominent role of SA in regulating plant responses to other forms of attack, it should come as little surprise that feeding by insect herbivores can also induce SA mediated effects for plant defense. While SA is relatively better explored in the context of pathogen defense, insects-particularly sucking insects-can also elicit responses. Aphid feeding by the green peach aphid ( defense . Feedingsistance . Likewissistance . Such re pathway .Helicoverpa armigera Hubner) [Additionally, there is some evidence that SA may be involved in defense against chewing insects. While many studies of plant defense pathway induction by chewing insects point to the role of the JA pathway  in media Hubner) .Induction of the SA acid pathway in response to attack by plants, pathogens, and pests is not a given, however. Other factors can play a role. Endogenous levels of other plant hormones can be crucial in determining whether and how SA related responses develop within a plant ,72. EthyPseudomonas in Arabidopsis [Alternaria fungus in potato [Phytophthora infestans in potato [Induction of the SA pathway has a direct role in mediating interactions with and between pathogens and herbivores. As was touched on briefly, activation of SA related plant defenses can result in production of PR proteins and induction of SAR with negative consequences for infecting pathogens ,37,45,49bidopsis , resistan potato , rice bln potato , and defn potato . In addin potato .Community effects of SA mediated plant defenses are not only limited to effects at the micro-organism community level, but also extend to other plants. Volatile communication between plants can cause cascading effects of SA induction in plant communities by triggering SA related defenses in neighboring plants ,85. ThisManduca and Operophtera [Similarly, SA induction can have negative consequences for the fitness of attacking herbivores. As a defensive molecule, phenolic compounds such as SA can act as deterrents and be toxic to insect herbivores . In willrophtera ,93. Alsorophtera .Arabidopsis, egg deposition and larval feeding by Pieris brassicae can interact to induce higher SA levels [Arabidopsis mutants deficient in SA pathway components do not show the same larval effects [P. brassicae in Arabidopsis, but also potentially affects oviposition behavior; MeSA tends to deter oviposition by P. brassicae when either dispensed exogenously or expressed constitutively at high levels [SA induction can have additional direct effects against insect herbivores. In A levels . SA can A levels  and larvA levels . At the A levels . Larvae A levels . Importa effects . SA not h levels . Similarh levels ,99.Heliothis virescens larvae [Fitness effects of SA induction are not always negative for the offending herbivore, however. In tobacco plants infected with the tobacco mosaic virus, over-expression of PAL increases SAR to the tobacco mosaic virus while under-expression weakens it . The invs larvae . This phs larvae ,101. As Helicoverpa zea larvae on tomato leaves caused a reduction in infection by the bacterial pathogen Pseudomonas syringae [The preceding example is one prominent case of the SA pathway mediating indirect interactions between plant pathogens and insect herbivores. The ecological consequences of these indirect interactions are only beginning to be understood, but exist in numerous study systems. Interactions can go both ways; in the above example, SA was shown to play a role in pathogen resistance affecting herbivore feeding but herbivore feeding can also impact pathogen infection. Feeding by syringae . While Ssyringae  and can syringae . The mecsyringae ,105,106.Arabidopsis and bean [The role of the SA pathway in mediating ecological effects and interactions between other organisms has an inter-generational temporal component as well. There are epigenetic effects of SA mediated plant defense signaling . DNA metand bean ,110,111.Just as induction of the SA pathway has primary metabolic consequences for the plant and secondary consequences for other organisms such as pests and pathogens, induction of the SA pathway can have tertiary effects on additional trophic levels affecting behavior and recruitment of natural enemies both aboveground and belowground.Since early work showing the role of herbivore induced plant volatiles in recruiting natural enemies aboveground , the rolOne prominent cue that can be directly linked to induction of the SA pathway is the volatile methyl salicylate (MeSA). MeSA is a phenolic signal produced from SA and is involved in plant-plant communication as a mobile and volatile signal for systemic acquired resistance ,53. MeSAArabidopsis thaliana plants compromised in the production of MeSA with wild-type plants, MeSA compromised plants were more attractive to parasitoids, natural enemies of biotic stressors, than their wild-type counterparts releasing MeSA [Predators and parasites of these insect herbivores can also perceive and respond to MeSA. Indeed, MeSA has been shown to be attractive to a wide range of insect natural enemies ranging from micro-hymenoptera to lacewings in laboratory and field studies . In manying MeSA .While the SA pathway plays a significant role in regulating plant defenses and mediating interactions with herbivores and natural enemies aboveground, its role in belowground indirect defenses is just beginning to be understood. Plants inhabit two distinct environments; just as the shoots and leaves of plants aboveground can benefit from recruitment of natural enemies to reduce aboveground herbivore pressures, so too can plant roots. Belowground herbivory is an important factor affecting plant performance, if relatively unexplored . New metIn addition to adapting to two distinct environments, plants must also contend with an embedded corollary; natural enemies belowground are inherently different than those aboveground. Parasitic wasps tend to be less effective against belowground herbivores. Instead, natural enemies belowground can include entomopathogenic nematodes and soil-dwelling mites. Similar to aboveground systems, belowground feeding by root herbivores can induce release of volatiles that recruit predatory mites  and entoThe role of the SA pathway in mediating these changes is just beginning to be explored. Exogenous application of MeSA in citrus and corn plants can cause recruitment of entomopathogenic nematodes ,133. In This work suggests a specific role for SA in not only connecting belowground and aboveground plant systems, but also in mediating tertiary effects between aboveground organisms and belowground natural enemies and vice versa. Indeed, recent work showed that belowground feeding by insect larvae can induce release of volatiles aboveground attractive to parasitoids of the adult insect . While nInduction of the SA pathway has clear ramifications for plants, pathogens, herbivores, and natural enemies above and belowground with ecological consequences radiating from SA mediated interactions at multiple trophic levels. Observation of these types of effects naturally leads to contemplation of possible application in agriculture. Using the SA pathway in agriculture to manage pests and pathogens has generally followed three approaches: (1) exogenous application of compounds that induce the SA pathway for direct plant defense; (2) genetic modification of plants to alter plant defense expression; (3) exogenous application of SA related volatile compounds  to attract natural enemies that control insect pests.Nicotiana benthamiana increased resistance to challenges by the bacterial pathogen Pseudomonas syringae [Early investigations into using exogenous applications of SA inducing compounds to elicit plant defenses pathways, induce resistance, and augment SA signaling opened the way for consideration of novel management strategies for control of agricultural pests and pathogens. Exogenous application can take many forms involving a wide range of elicitors and synthetic SA analogs that can result in SAR and enhanced resistance to pathogen load ,148. In syringae . Repeatesyringae  suggestisyringae . Effectssyringae .This approach could not only have appreciable effects on plant disease, but also increase yield. In some crop systems, exogenous application of elicitors can have beneficial effects for crop management comparable to pesticide controls . In seveFusarium oxysporum f.sp. cucumerinum) in cucumber, for example, does not respond to exogenous induction of SAR [Rhizoctonia solani, the causal agent of sheath blight disease in the grain species Brachypodium distachyon because it induces genes related to JA signaling [Beneficial outcomes on disease management from exogenous application of SA elicitors are not guaranteed, however. Results can be dependent on the identities of the plant and pathogen species . Fusariun of SAR . Multipln of SAR . These uignaling . In thisignaling .Non-beneficial agricultural outcomes of exogenous induction of SA defenses are not limited to lack of pathogen control, however. As discussed above, stimulation of systemic acquired resistance may be beneficial in reducing pathogen load, but may result in crop plants becoming more susceptible to herbivory . There aAn ideal solution to address the challenges and trade-offs listed above would be crops that have defenses turned off in situations where pest and pathogen pressure is absent that then are strongly activated in situations where pest and pathogen pressure are prevalent . While tArabidopsis and rice resulting in resistance to agriculturally relevant pathogens across generations while balancing fitness and yield costs [Recent work shows promise in obviating those drawbacks by developing a switch that would balance defense and production trade-offs . Inductild costs . These rWhile engineering plants that selectively activate SA defense pathways in areas of high pathogen pressure holds considerable promise for defense against plant pathogens, herbivore pressure can also substantially impact yields. The SA pathway has limited efficacy for defense against herbivore pests of agricultural pests. As discussed above, SA can play a role in direct defense against sucking insects such as aphids ,67,68,69The efficacy of this approach on reducing pest populations could be highly variable however and merits further exploration into appropriate means of implementation. Attraction of large numbers of predators and parasitoids may have non-target effects and does not necessarily result in improved pest control; attracted natural enemies may not necessarily be effective in controlling the offending pest species for several reasons including phenology (pest life stage plays an important role in susceptibility), relative population densities, and competing hosts . AdditioKnowledge of SA related defense signaling and potential applications to agricultural challenges burgeoned in recent years. While there is substantial work that remains to be done in understanding basic mechanisms behind primary, secondary, and tertiary ecological effects of SA signaling, what work that has been done points to numerous opportunities for developing methods that enhance sustainable production of important agricultural crops through efficient and efficacious management of abiotic and biotic challenges. These contributions could engender a second green revolution: a plant defense-based revolution-leveraging intelligent adaptations to abiotic and biotic challenges to preserve and increase sustainable crop yields and feed a hungry planet.


Emerging evidence has shown that mitochondrial pathways are potential therapeutic targets for cancers. Mitochondria are the central organelles for energy production, but also play a pivotal role in lipid and amino acid metabolism, redox and calcium homeostasis, transcription regulation, as well as cell fate determination. Previously we and others have demonstrated that disruption of mitochondrial function selectively targets acute myeloid leukemia (AML) cells ,2. IdentIn our recent publication in Cell Stem Cell , we utilWe interrogated the function of TAZ in AML through a series of functional assays. Loss of TAZ reduced proliferation, supressed clonogenic growth and induced differentiation in AML cells. Of note, knocking down TAZ in mice did not affect normal hematopoiesis, suggesting a specific dependence of AML cells on TAZ.As TAZ is a key enzyme for phospholipid biosynthesis, we examined the phospholipid profile of AML cells upon TAZ knockdown. In addition to the expected decrease in mature cardiolipin, we noticed increased levels of phosphatidylserine (PS) and decreased phosphatidylethanolamine (PE). Further study showed that supplementing TAZ knockdown cells with PE did not rescue the loss in proliferation. In contrast, supplementation of PS mimicked the effects of TAZ knockdown and decreased AML growth and stemness.Furthermore, phosphatidylserine decarboxylase (PISD), a mitochondrial enzyme that converts PS to PE, was downregulated at post-transcriptional level following TAZ knockdown. By lipid-protein overlay assay, we found that PISD recombinant protein bound cardiolipin and the cardiolipin moiety phosphatidylglycerol. CRISPR/Cas9-mediated knockout and chemical inhibition of PISD recapitulated the effects of knockdown of TAZ. Taken together, we discovered that TAZ modulates PISD activity to control intracellular levels of PS, which in turn regulates AML stemness and differentiation.Mechanically, we discovered that TAZ knockdown or increasing levels of PS up-regulated genes in the Toll-Like Receptor (TLR) pathway. We also showed that activation of the TLR pathways was functionally important to induce AML differentiation. Finally we used preclinical animal models to demonstrate that PISD inhibitor, MMV007285, reduced AML disease burden and targeted AML stem cells without toxicity.in vitro and less leukemic engraftment in vivo. We also discovered that intracellular PS inhibited AML growth and stemness by activating the TLR pathway. This finding implicates a novel function of PS in regulating cell growth and stemness. It also drives further studies on how PS mediates the TLR activation and the roles of inflammatory pathways in AML differentiation.This work provides new insights into the roles of TAZ in AML, and highlights the important role of PS in maintaining AML stemness. PS is an essential phospholipid which is normally restricted to the inner leaflet of the cell membrane. Previous studies on PS focused on the translocation of PS to the cell surface. For example, the externalization of PS has been considered as a hallmark of apoptosis . ExposedAt the therapeutic level, this paper proposes a novel mechanism to target leukemia stem cells (LSCs), which are the subpopulation of cells responsible for AML progression and relapse. Previous studies have shown that LSCs display unique metabolic properties, including relatively low levels of reactive oxygen species , sensitiIn summary , we disc


It is well established that gardening can promote physical, social, and emotional wellbeing for many older adults in varied circumstances . In post-industrial cities formed by historical and ongoing processes of structural inequality such as Detroit, Michigan, gardening is beneficial for residents in terms of health, economic activity, community-building, and city beautification . However, research has less frequently investigated how gardening can promote wellbeing for older adults living in contexts of urban structural inequality. This poster addresses this gap by exploring how older African American gardeners in Detroit adapt their gardening practices to changing physical abilities and capacities. Drawing on ethnographic research conducted during one gardening season (March-October 2017) with older African Americans in Detroit (n= 27), we employ a selective-optimization-with-compensation framework  to understand the modifications that older Detroiters make in their gardening practices as they age. Findings demonstrate that older African Americans in Detroit engage in gardening in flexible, creative ways that accommodate new physical limitations, while also connecting to changes occurring in the city of Detroit. This study thus has implications for further understanding how gardening can benefit older adults, and how older adults can contribute vitality to contexts of structural inequality.


Fatigue fractures are stress fractures resulting from repetitive trauma in areas of stress concentration. Prior case reports and studies have described stress fractures through persistent physes about the olecranon and distal fibula, as evidenced by hyaline cartilage on histologic analysis. However, there have been no documented proximal tibia stress fractures through persistent physes.  A 29-year-old military male basic trainee with varus alignment about his knees suffered bilateral medial tibial plateau stress fractures several weeks into military basic training. He underwent radiographic and laboratory evaluation of his stress fractures and eventual operative fixation of his bilateral tibial plateau fractures. Intraoperative specimens obtained from the fracture sites distal to the articular surface demonstrated abnormal fibrous appearing tissue. Histology demonstrated the presence of hyaline cartilage.  A 29-year-old military male basic trainee had bilateral proximal tibia stress fractures through persistent physes confirmed with biopsies demonstrating hyaline cartilage. Our belief is that the patient's persistent physes placed him at a greater risk for stress fractures and these may benefit from fixation in soldiers and athletes. Fatigue fractures are stress fractures resulting from repetitive injury at areas of stress concentration. Stress injuries, or overuse injuries, are very common in military recruits with one study demonstrating a 31% incidence of overuse injuries in basic military trainees , 3. RareA 29-year-old military male basic trainee  presented with a one-month history of atraumatic bilateral leg pain. He reported pain within the first week of initiating running at basic training. He was diagnosed with bilateral proximal tibia stress fractures at three weeks with instructions to stop impact activities. After failure of his symptoms to improve, he was referred to our facility. On presentation, he had tenderness about the medial aspect of each proximal tibia. Radiographs obtained at that time demonstrated bilateral proximal tibia stress fractures with varus alignment about each knee and articular collapse of the left tibial plateau. Metabolic labs were obtained and significant for a low vitamin D (15), but the remainders of labs including calcium, thyroid-stimulating hormone (TSH), and testosterone were unremarkable. MRI of the left knee demonstrated a medial tibial plateau fracture with two millimeters of articular depression and extension of the fracture to the tibial spine . MRI of At the six-week follow-up visit after the procedure on his left knee, the patient was still having significant pain in his right lower extremity and, after extensive counseling, elected to undergo the same procedure on the contralateral limb in an effort to return to running and continue his military career . We suspAt four-and-a-half months from the index procedure (three months from the staged procedure), the patient was ambulating without assisted devices and had painless range of motion from 0 to 120° in each knee with well-healed incisions, maintained hardware and alignment, but had not returned to impact activities. Due to his status as a basic trainee, he was released from active duty at six months' time postoperatively and was lost to follow-up.Our 29-year-old patient presented with bilateral proximal tibia stress fractures through persistent physes, which has not previously been reported in the literature. Typically, the proximal tibia physis closes at 18-19 years of age in males and 16-17 years of age in females . BiopsieWith regard to nonphyseal stress fractures, the tibia is the most common site of stress fractures (49.1%), with the most common location of stress reaction being the posteromedial diaphyseal cortex . HoweverWhen evaluating stress fractures, factors that need to be considered include metabolic abnormalities and malalignment. To evaluate metabolic contributions to stress fractures, a laboratory workup should be completed. This should include a complete metabolic panel, including serum calcium, albumin, alkaline phosphatase, serum vitamin D levels, as well as calculated GFR, and relevant hormonal levels  . As our Prior studies have reported on the successful treatment of proximal olecranon stress fractures in throwers through persistent physes with resection, bone grafting, and internal fixation , 6, 15. Stress fractures of the proximal tibia may occur through persistent physes. Things that suggest a persistent physis being present include a visualized physis on imaging, surrounding sclerosis on radiographs, and easily debrided material at the fracture site creating a cavitary lesion or void at the level of the suspected physis. Studies have demonstrated the successful treatment of fractures through persistent physes about the olecranon with resection, bone grafting, and internal fixation. Nonoperative management with protected weight bearing is reasonable when treating nondisplaced proximal tibia stress fractures through persistent physes due to the compressive rather than tension forces occurring in the proximal tibia. For patients with articular collapse or for those active patients who do not have the time for prolonged weight bearing restrictions, resection, bone grafting, and internal fixation may allow these patients to more quickly heal from their injury. Further research is needed to investigate this but is challenging given the rare nature of this injury.We present a 29-year-old male basic trainee with bilateral proximal tibia stress fractures with intraoperative biopsies demonstrating the presence of hyaline cartilage and persistent physes treated by excision, bone grafting, and internal fixation. Persistent physes of the proximal tibia may be prone to stress fracture and subsequent collapse of the articular surface and may benefit from resection and fixation when recognized in active duty soldiers and athletes.


Lay Summary: This review sets out the hypothesis that life history trade-offs in the maternal generation favour the emergence of similar trade-offs in the offspring generation, mediated by the partitioning of maternal investment between pregnancy and lactation, and that these trade-offs help explain widely reported associations between growth trajectories and NCD risk.Growth patterns in early life predict the risk of non-communicable diseases (NCDs), but adaptive explanations remain controversial. It is widely assumed that NCDs occur either because of physiological adjustments to early constraints, or because early ecological cues fail to predict adult environmental conditions (mismatch). I present an inter-generational perspective on developmental plasticity, based on the over-arching hypothesis that a key axis of variability in maternal metabolism derives from life history trade-offs, which influence how individual mothers partition nutritional investment in their offspring between pregnancy and lactation. I review evidence for three resulting predictions: (i) Allocating relatively more energy to growth during development promotes the capacity to invest in offspring during pregnancy. Relevant mechanisms include greater fat-free mass and metabolic turnover, and a larger physical space for fetal growth. (ii) Allocating less energy to growth during development constrains fetal growth of the offspring, but mothers may compensate by a tendency to attain higher adiposity around puberty, ecological conditions permitting, which promotes nutritional investment during lactation. (iii) Since the partitioning of maternal investment between pregnancy and lactation impacts the allocation of energy to ‘maintenance’ as well as growth, it is expected to shape offspring NCD risk as well as adult size and body composition. Overall, this framework predicts that life history trade-offs in the maternal generation favour the emergence of similar trade-offs in the offspring generation, mediated by the partitioning of maternal investment between pregnancy and lactation, and that these trade-offs help explain widely reported associations between growth trajectories and NCD risk. There is compelling evidence that patterns of nutrition and growth during early life shape diverse components of adult phenotype, as recognized in the developmental origins of adult health and disease (DOHaD) hypothesis . While tMany researchers consider two ‘adaptive’ models of developmental plasticity—either that it reflects developmental adjustments to resolve effects of early constraints on nutritional supply, or that it adjusts phenotype to current ecological cues in anticipation of experiencing similar conditions in adulthood . HoweverAn alternative approach is to consider early developmental plasticity as a response to the magnitude and scheduling of maternal nutritional investment, thus exposing each offspring to patterns of investment that maximise maternal fitness . PreviouNutrition is the key mechanism through which mothers invest in offspring in early life. In placental mammals, both pregnancy and lactation involve the transfer of energy, nutrients, cells, hormones and immune agents from mother to offspring. Maternal metabolism underpins both processes, but the limiting factors differ, and this has major implications for the overall profile of nutritional investment and its variability between mothers.In energetic terms, placental nutrition is cheaper than lactation , 7. BeinBeyond energy costs, several physiological constraints on maternal investment during pregnancy become less relevant after delivery. As discussed below, these relate to maternal metabolic turnover, body size and bio-thermodynamics during pregnancy, whereas they relate primarily to energy balance during lactation. The relationship between maternal phenotype and the magnitude of nutritional investment therefore shifts following delivery.It might seem irrelevant how much investment is received by each offspring before versus after birth, providing that the sum total over the combined period is similar. However, the relative magnitudes of growth achieved before and after birth have major implications for adult body size, composition and metabolism, and for long-term health and demographic outcomes . The relNutritional investment during pregnancy has unique benefits. Most rounds of cell division occur before birth , hence fAfter birth, elevated energy supply can accelerate weight gain, however this may also generate costs, such as excess fat deposition, oxidative stress and telomere attrition , 19. Rapin utero [Delaying growth to post-natal life therefore has very different phenotypic effects compared to growth in utero , and earin utero . Both smin utero , 22.The ‘partitioning’ of maternal investment across successive periods incorporates a dynamic element. Smaller neonates tend to undergo a degree of catch-up in early post-natal life while larger neonates show slower infant growth , though maintenance, growth, reproduction and defence [From an evolutionary perspective, variability in early growth patterns can be re-interpreted within an adaptive framework. Life history theory treats energy as a limited resource, that must be allocated competitively between  defence . Relativ defence . One pow defence . Exactly defence , 31. Low defence , and henMost adaptive explanations for developmental plasticity have focused on individuals, and how they respond to diverse ecological factors . Howeverpartitioning of maternal investment between pregnancy and lactation is both a consequence of the mother’s own life history trajectory, and also a contributing factor to life history trajectory in the following generation. This generates three specific predictions:Mothers allocating relatively more energy to growth during their development are able to promote nutritional investment in their offspring during pregnancy.Mothers allocating relatively less energy to growth during their development are unable to invest as much in pregnancy, and compensate by allocating energy to fat stores, which promote nutritional investment in their offspring during lactation.These trade-offs affect ‘maintenance’ in both mothers and offspring, and thereby contribute to variability in NCD risk in both generations.This review develops the hypothesis that the Maternal basal metabolism comprises a key constraint on the magnitude of growth attainable by the fetus . Across As pregnancy progresses, however, maternal metabolism reaches an inherent limit in its ability to transfer energy to the fetus, due in part to the high glucose demands of the fetal brain . Human bThe importance of maternal basal metabolism for fetal growth is supported by studies in diverse settings: with the exception of one small Swedish study, maternal fat-free mass (FFM), the primary site of energy and protein metabolism, is consistently reported to be a stronger predictor of offspring birth weight than maternal fat mass . Above aMoreover, maternal body size has several other implications for the magnitude of investment during pregnancy. First, a larger FFM increases the energetic efficiency of funding fetal growth. Second, ecological factors may also constrain maternal BMR. For example, BMR is around 4.5% lower in tropical populations, even after controlling for body size . Lower hThird, beyond metabolic pathways, maternal height may also constrain fetal growth. The increased risk of low birth weight offspring among mothers of maternal short stature is mediated in part by reduced intra-uterine volume , 56. SimIn conclusion, larger mothers with greater height, FFM and skeletal dimensions are able to invest more during pregnancy than smaller mothers. The association between maternal phenotype and the capacity for nutritional investment during lactation, however, is different.de novo synthesis, or from body fat stores [Humans are ‘capital’ breeders, storing energy in advance in order to fund reproduction regardless of dietary energy availability . Consistt stores .Prior to reproduction, women store fat disproportionately in the gluteo-femoral region, and even in populations with low average BMI, around 20–25% of body weight is fat. Additional fat accretion typically occurs during pregnancy, ranging from <1 kg in energy-constrained settings ∼3.5 kg in well-nourished populations, and up to ∼0.8 kg per month can be lost during lactation , again dAlongside fat oxidation, the energy costs of lactation may be met from dietary energy intake. Averaging across several studies, energy intake increased by ∼360 kcal/day by peak lactation, representing over half the costs of lactation, but again there was also substantial variability between populations .Within populations, a number of studies report that mothers who are fatter or gain more energy stores during pregnancy have infants who gain more weight . This maImportantly, the contribution of gluteo-femoral fat to lactation relates not only to its energy content per se, but also to specific fatty acids that promote infant brain development. Beyond absolute reductions in energy stores, lactating mothers tend to redistribute fat from lower to upper body depots, allowing the diversion of fatty acids from gluteo-femoral depots to the offspring , 78.Of particular relevance to the hypotheses under discussion here, substantial catch-up in weight, length and head circumference is possible in breast-fed infants born small for gestational age , providiIn summary, therefore, maternal adiposity plays a key role in nutritional investment during lactation, and this contrasts with pregnancy where FFM and BMR are more important somatic factors. Why, however, do individual mothers vary in their relative investment during these two successive periods? I hypothesise that the mother’s life history is a key factor shaping the partitioning of investment, and that this generates correlated levels of energy allocation to growth and maintenance in each generation.According to life history theory, environments with high mortality risk and shorter life expectancy promote the allocation of energy to survival and reproduction over growth and maintenance , 28. SpeThe functional trade-offs that underlie life history variability are very apparent in somatic traits . IncreasFor example, reducing energy allocation to growth during maternal development (resulting in short stature and reduced FFM) reduces the capacity for maternal investment during pregnancy. This equates to constraint of investment in ‘maintenance’ during early ‘critical windows’, and indicates a shorter expected lifespan and duration of the reproductive career of the offspring , 30. FetConsistent with that, several studies have linked early growth constraint with some degree of preservation of fatness , though In similar manner, under conditions of persistent energy scarcity both growth and maturation rate are constrained, such that if energy supply increases, menarche occurs earlier while growth also increases . When poThe inter-generational transmission of female life history strategy is evident in the UK ALSPAC cohort, where mother’s age at menarche was associated with early growth patterns, maturation rate and adolescent body composition of daughters. Mothers who had experienced earlier menarche were shorter and fatter compared to those who had experienced later menarche . Their dTo summarize this analytical framework, Several studies have highlighted how greater maternal investment during infancy accelerates the pace of maturation among female offspring . Across In summary, the available evidence indicates that maternal somatic trade-offs between linear growth and adiposity are associated with differential partitioning of investment in the offspring between fetal life and infancy.So far, this paper has argued that mothers are subject to life history trade-offs, and that this shapes developmental trajectory in the next generation. Because these trade-offs affect not only growth/reproduction but also the relative allocation to ‘maintenance’, it becomes clear that an additional connection is between life history strategy and metabolic health, best conceptualized through risk of chronic non-communicable diseases (NCDs). On this basis, since life history trade-offs are transmissible across generations, so is the risk of NCDs, strongly mediated by early growth patterns  and subsequent adiposity .in utero, lower birth weight was associated with earlier menarche, shorter adult stature, higher levels of body fat, and higher blood pressure [For example, a study of South Asian women in the UK showed how maternal investment in fetal life shapes the subsequent life history trajectory of daughters. Using birth weight as a simple proxy for maternal investment pressure . This inAnother study showed how these associations become magnified when the shift between fetal and post-natal nutrition becomes more extreme. Indian girls who migrated to Sweden very early in life initially demonstrated very poor levels of growth, but nevertheless underwent precocious puberty and became short, highly adipose adults . In bothAccording to the arguments above, the transmission of life history strategy across generations is expected to correlate not only with differential somatic phenotype, but also a broader range of health outcomes. Greater fetal weight gain indicates greater investment in maintenance, predicting a longer lifespan, as well as growth. We should therefore expect larger birth weight, later menarche and taller adult height all to correlate with lower NCD risk, as well as the potential to transfer the same life history strategy to the next generation. Conversely, reduced fetal weight gain followed by catch-up growth, accelerated maturation and adiposity, is predicted to superimpose a high metabolic load on a diminished metabolic capacity, resulting in elevated NCD risk .Consistent with this perspective, numerous studies have linked somatic markers of trade-offs favouring survival and reproduction over growth and maintenance with elevated adult NCD risk. Beyond well-established inverse associations with birth weight, many NCD risk factors are elevated in association with short stature, including insulin resistance, elevated blood lipids, and higher blood pressure . Likewisin utero, but post-natal catch-up was likely also limited [One final issue is to consider how ecological conditions interact with these trade-offs. Many populations have a long history of lower average birth weight, indicating limited maternal investment  limited . Such po limited , 114. ThIn this review, I have developed earlier arguments to set out a new perspective on the adaptive basis of developmental plasticity. Most researchers assume either that developmental plasticity allows response to resource limitations (e.g. sacrificing one function or trait to protect another), or that it allows an adaptive response to immediate cues in anticipation of matching phenotype to adult conditions.I have developed a different perspective, proposing that developmental plasticity incorporates adaptation of the offspring to the magnitude of maternal capital. What I add here is that the mother’s capacity to transfer capital depends on life history trade-offs that occurred during maternal development, and that the value of a given unit of capital to the offspring depends on the stage of development when it is received. Because fetal and infant growth variability have very different associations with long-term phenotype, the mediation of maternal nutritional investment by her life history trajectory generates important trade-offs in the offspring between growth, reproductive potential and health. The partitioning of maternal capital transfer between pregnancy and lactation therefore merits further attention.per se, as the primary source of developmental constraints in the offspring. This is an important difference, for two reasons. First, mothers within a population can vary substantially in their life histories, despite inhabiting a common environmental niche, due to a range of social and physical factors acting across generations. Second, mothers may vary their investment in individual offspring in order to tailor reproductive strategy to ecological conditions. For example, where extrinsic mortality risk is high, mothers may increase offspring quantity at the expense of offspring quality. A combination of reduced linear growth and diverting available energy to fat stores may contribute to such a strategy.This approach helps explain why life histories and health status may show some consistency across generations, without appealing to environmental ‘prediction’ or ‘anticipation’. Rather, maternal trade-offs that constrain her investment in her own growth and maintenance are proposed to steer the offspring to make similar trade-offs in the next generation. My approach differs from previous work by emphasising the mother’s response to selective pressures, rather than environmental conditions Relevant trade-offs between growth, maintenance, reproduction and survival traits may be tested in epidemiological studies. In an accompanying article, for example, Macintosh and colleagues apply this theoretical paradigm to bone phenotype in a sample of women in the UK. Consistent with predictions, markers of trade-offs favouring growth and maintenance  are associated with stronger and longer bones in adult women, indicating a lower risk of osteoporosis. In contrast, earlier menarche is associated with greater adiposity. This study therefore provides support for the hypothesis that maternal life history strategy encompasses both somatic and functional trade-offs between reproductive potential and maintenance/health. Broadly, this perspective provides an evolutionary explanation for the extensive biomedical literature linking markers of growth and maturation with NCD risk and lifespan.More detailed measurements of maternal and offspring body composition through the periods of pregnancy and lactation would help establish with greater confidence the extent to which maternal investment is indeed partitioned between pregnancy and lactation in association with trade-offs between height and adiposity. Another key area for future work is to investigate whether such somatic and functional trade-offs apply to male as well as female life history strategies. Given the low level of nutritional investment provided by fathers, some of the associations described here for female life histories may not necessarily apply to males.Conflict of interest: None declared


Graphene has made significant contributions to neural tissue engineering due to its electrical conductivity, biocompatibility, mechanical strength, and high surface area. However, it demonstrates a lack of biological and chemical cues. Also, it may cause potential damage to the host body, limiting its achievement of efficient construction of neural tissues. Recently, there has been an increasing number of studies showing that combining graphene with other materials to form nano-composites can provide exceptional platforms for both stimulating neural stem cell adhesion, proliferation, differentiation and neural regeneration. This suggests that graphene nanocomposites are greatly beneficial in neural regenerative medicine. In this mini review, we will discuss the application of graphene nanocomposites in neural tissue engineering and their limitations, through their effect on neural stem cell differentiation and constructs for neural regeneration. Peripheral nerve injury (PNI) has been widely reported to be an essential cause of incapability in the clinical setting. Patients suffering from this disease encounter many challenges including pain, sensory loss, impaired movement, and cold intolerance, which have a significant adverse impact on their daily life . The mossp2 hybridization, forming a honeycomb pattern throughout the 2D plane [Recent advances in tissue engineering and regenerative medicine have paved the way for the development of many strategies in peripheral nerve repair and various functional topographical scaffolds such as gels, films, electro spun fibers, and grooves which have been successfully demonstrated to support neuronal cellular attachment and migration . Due to 2D plane . Highly 2D plane . Notably2D plane ,14. Comp2D plane . However, while pristine graphene can induce synaptogenesis and sustain neuronal growth, pure graphene sheets fail to recapitulate the intrinsic neural microenvironment in vivo due to its smoothness, chemical inertness and lack of biological cues ,19,20. IIn this mini review, we will first touch upon the structure and functions of graphene nanocomposites. The main focus will be on recent research advances in graphene-based nanocomposites for application in neural tissue engineering. Finally, we will provide a summary and perspectives for using graphene nanocomposites as the next generation of materials for neural tissue engineering.Graphene-based nanomaterials (GNs) can be subdivided according to the number of layers, sheet dimensions, surface chemical modification status, and defect density. The most widely applied ones are single-layer graphene, few-layered graphene, GO, as well as reduced graphene oxide (rGO), as shown in Inspired by their fascinating physical and chemical properties, the GNs have been widely applied to neural tissue engineering; however, some substantial problems have significantly hindered their application. For example, most of the above GNs have been demonstrated to possess an aggregation tendency, cytotoxicity and insufficient bioactivity in physiological environments because of the strong interaction among nano-sized graphenes, uncleared biocompatibility and their inherent bio-inert nature . Thus, fUtilizing graphene’s unique surface and electrical properties to mimic in vivo cues to enhance the differentiation of stem cells into neurons is an extremely attractive strategy for the treatment of neuronal injuries and diseases. Reports have shown that GN-based materials promote stem cells to differentiate into neurons, as well as improve their proliferation rate ,49,50. HIn one study, Akhavan et al. cultured neural stem cells (NSCs) on ginseng-reduced GO nanosheets to improve the material’s biocompatibility and capability for electron transfer . Using gTo investigate the effect of the physical cues of graphene composites on human neural stem cells (hNSCs), Solanki et al. functionalized laminated GO nanoparticles on charged glass to form aligned patterns, matching the extracellular matrix (ECM) protein patterns in the human body . GO was However, the aforementioned studies were only able to capture the differentiation of NSCs on a 2D plane, which is very different from the three-dimensional (3D) ECM nanostructure. The signaling between cell-microenvironment interaction and attachment of cells onto a 3D dynamic network of macromolecules is essential to maintaining stem cell homeostasis . In addi2 matrix containing TiO2 nanoparticles. After 3 weeks of differentiation, the number of cells increased up to ~26.8-fold. Notably, the nano-grids showed lowered electrical resistance due to the connection by neurite network, implying that formation of cell-to-cell electrical couplings existed in the differentiated network. However, the neural network formed by nano-grids was limited to the 2D plane. Hence, researchers have been searching for substitutes such as nanofiber scaffolds for cultivating neural cells [Other than promoting neuronal differentiation to replace damaged tissues, GNs can also directly stimulate neural regeneration as electrodes. Electrical stimulation is vital to promoting cell proliferation and mimicking in vivo neural networks as neural cells are interconnected via neurites in native tissues . For exaal cells . Electrically conductive nanofibers additionally provide cells with favorable 3D architecture and appropriate flexibility similar to neurites in the human body. The attractiveness of using graphene to fabricate nanofibers instead of traditional conductive materials such as carbon nanotubes and poly comes from graphene’s superior electrical properties and mechanical strength. While the smooth transition from graphene’s 2D sheet to 3D nanofibers may prove to be difficult, Feng et al. circumvented the problems by assembling a GO sheet onto the surface of electro-spun poly (vinyl chloride) nanofibers, allowing the surface of the nanofiber to be wrapped tightly with graphene . The fibIn conditions like glaucoma, high intraocular pressure induces lesions in the optical nerves. While reduction of pressure can halt the damage done to retinal ganglion cells, their function cannot normally be recovered. However, the construction of nanofibrous scaffold using graphene, conductive polymer polypyrrole and polylactic-co-glycolic acid (PLGA) allowed for a high surface area for cell attachment as well as high capacitance for electrical stimulation, guiding cell neurites to regenerate along aligned fiber patterns. Through electrospinning, a fibrous mat structure with diameter at 110 nm was collected. It was shown that the fibers have tunable electroactivity by varying the ratios of graphene and polypyrrole in PLGA, allowing for a flexible therapy for optical nerve-related diseases. Results also showed the importance of electrical stimulation to the anti-aging ability of retinal ganglion cells. Without electrical stimulation, the cells showed decreased size, increased roundness and number of tentacles, resulting in mass apoptosis and lowered cell viability to 40% of the original. The ganglion cells, however, remain healthy after 10 days when electrical stimulation was applied, showing the essentiality of electrical stimulation to neural constructs. Reports have showed that electrical stimulation is essential to calcium-dependent neurite outgrowth and immediate gene expression, and that regeneration rate is frequency-dependent . Hence, While graphene itself can be used as a substrate, platelets of graphene can also be infused with other materials such as polymers to exhibit specific bulk properties while retaining its conductivity and chemical cues . AlthougAdditionally, GNs were applied in neural regeneration through drug loading and delivery through the blood brain barrier, which is normally impassable for drug molecules ,64. A naNeurodegenerative and neurological diseases like Alzheimer’s disease and Parkinson’s disease threaten an ever-increasing percentage of our ageing population. Studies have shown that deep brain stimulation and recovery of sensory capabilities by electrical stimulation based on neural recordings are extremely beneficial to neural regeneration . Hence sIn one study, Kuzum et al. fabricated transparent graphene electrodes for simultaneous electrophysiology recording and neuro imaging using graphene and polyimide . The fleGraphene has been widely proved to play a vitally important role in the proliferation and differentiation of neural cells. Significant progress has been made during the past decades in the development of graphene-based materials ,55. Up tWith the increasing utilization of graphene in a variety of biomedical applications, the in vitro and in vivo biocompatibility of graphene and its derivatives and their probable toxicities must be taken into consideration. The critical parameters which result in toxicity using graphene-based materials are: (1) The size, concentration, and shape. Smaller sizes and higher dose could lead to significant toxicities, giving rise to the fragmentations of DNA and/or chromosomal aberrations in living cells. The potentially sharp edges of graphene flakes or platelets would also result in physical damage of the wall membrane of cells and even nuclei through the direct contact interaction with cells; (2) Their possible aggregation, which may bring about adverse effects  to the blood circulation or immune system ; (3) IntAdditionally, most studies only focus on the exterior cell behaviors upon graphene exposure, thus, the interior effect of intracellular processes should be more emphasized ,75. For 2 nanoparticles and near-infrared ray-assisted photodegradation to provide a noninvasive method for circumventing this limitation [The possibility of biodegradation of graphene-based materials is another challenging issue, which should be solved especially when graphene impedes the effective interaction of cells and/or exchange of ions . Severalmitation ,79. HoweOverall, although there are still various unresolved issues and challenges, GNs are promising substances to pave the way for a real breakthrough in future studies of neural regenerative medicine.


Over the past few years, advances in molecular technologies have allowed unprecedented mapping of epigenetic modifications in gametes and during early embryonic development. This work is allowing a detailed genomic analysis, which for the first time can answer long-standing questions about epigenetic regulation and reprogramming, and highlights differences between mouse and human, the implications of which are only beginning to be explored.In this review, we summarise new low-cell molecular methods enabling the interrogation of epigenetic information in gametes and early embryos, the mechanistic insights these have provided, and contrast the findings in mouse and human.Relevant studies were identified by PubMed search.We discuss the levels of epigenetic regulation, from DNA modifications to chromatin organisation, during mouse gametogenesis, fertilisation and pre- and post-implantation development. The recently characterised features of the oocyte epigenome highlight its exceptionally unique regulatory landscape. The chromatin organisation and epigenetic landscape of both gametic genomes are rapidly reprogrammed after fertilisation. This extensive epigenetic remodelling is necessary for zygotic genome activation, but the mechanistic link remains unclear. While the vast majority of epigenetic information from the gametes is erased in pre-implantation development, new insights suggest that repressive histone modifications from the oocyte may mediate a novel mechanism of imprinting. To date, the characterisation of epigenetics in human development has been almost exclusively limited to DNA methylation profiling; these data reinforce that the global dynamics are conserved between mouse and human. However, as we look closer, it is becoming apparent that the mechanisms regulating these dynamics are distinct. These early findings emphasise the importance of investigations of fundamental epigenetic mechanisms in both mouse and humans.Failures in epigenetic regulation have been implicated in human disease and infertility. With increasing maternal age and use of reproductive technologies in countries all over the world, it is becoming ever more important to understand the necessary processes required to establish a developmentally competent embryo. Furthermore, it is essential to evaluate the extent to which these epigenetic patterns are sensitive to such technologies and other adverse environmental exposures. All cell types of an organism contain identical genetic information and yet are distinct in function and characteristics. Instructive epigenetic marks are key to this developmental conundrum. Epigenetic marks include modifications to the DNA or its associated proteins, which enable regulation of gene expression in a cell type-specific manner Fig. . Among tin-vivo studies.The field of developmental biology has long studied the intriguing nature of how two fully differentiated and very distinct cells, the sperm and the oocyte, can come together to create a totipotent embryo. Genetic studies in mice have firmly established that epigenetic regulation is key to the acquisition of totipotency during this transition. Early studies using molecular approaches and immunofluorescence showed that widespread epigenetic reprogramming accompanies both germ cell and embryonic development  employs the Tn5 transposase to integrate sequencing adapters into regions of accessible chromatin  methods evaluate chromosome interactions from a defined loci or throughout the nucleus, using cross-linking to ligate regions of DNA that lie in close proximity to each other  and a catalytically inactive co-factor (DNMT3L) are responsible for establishing cytosine methylation, usually in a CpG context (DNA methylation is established and maintained by a protein family of five DNA methyltransferases (DNMTs). Among these, three  context . Methyla context .http://weram.biocuckoo.org/), suggesting that the complexity of this system is extensive. In general terms, active and repressive histone marks, through their respective readers, can enable the immediately surrounding chromatin to be packaged in an open (accessible) or closed (inaccessible) conformation, respectively , DNA methylation begins to be re-established before birth (E15.5–E18.5) and is completed at the termination of meiotic pachytene after birth (D10–19) . DNA metShortly after the migration of germ cells to the gonad in females, there is massive mitotic expansion of this germ cell pool (E11.5). At E13.5, these oocyte precursors enter meiotic arrest in prophase I and remain quiescent in the developing ovary until after birth when they are assembled into primordial follicles. These cells represent the oocyte pool for the female’s entire lifespan, only a small subset of which will ever become fully mature and ovulate, as the vast majority will undergo apoptosis.de-novo DNA methylation in the phase of oocyte growth  oocyte, from a non-surrounded nucleolar-like body (NSN) to a surrounded (SN) state . Immediately after fertilisation, the paternal protamines are replaced by maternal histones accompanied by widespread erasure of almost all paternal DNA methylation. This was proposed to be active demethylation mediated through TET activity , but recLong-range and local chromosome interactions are not immediately restored in the post-meiotic zygote, as is the case for mitotic cells. Intriguingly, re-establishment of higher-order chromatin structure occurs independently of ZGA and cell cycle, suggesting that additional factors are required for re-establishing these interactions . Collectively, imprinted genes are essential for development, as demonstrated by embryo manipulation experiments used to generate embryos with exclusively maternal or paternal genomes  and their mono-allelic parent-of-origin DNA methylation persists through cell differentiation and into adulthood. GDMRs can regulate nearby genes, resulting in mono-allelic gene expression, termed genomic imprinting. In mice, there are 23 maternal and three paternal gDMRs regulating the gene expression of ~151 genes , key interactors (TRIM28/KAP1) and histone binding proteins (PGC7/Stella) .A recent study has also shown that genomic imprinting can be conferred by another epigenetic mark in addition to DNA methylation: maternal H3K27me3 inherited from the oocyte  was discovered, specifically active at young transposable elements during mouse spermatogenesis  , physiological factors , or medical interventions . In this section, we will provide an overview of the recent developments and future directions in these areas of research.DNMT3B and DNMT1 have been associated with male infertility  hypothesis posits that adaptive and maladaptive changes during foetal development in response to environmental exposures can result in predisposition to disease in adulthood , intra-cytoplasmic sperm injection (ICSI) and in-vitro culture, may increase the risk of developmental epigenetic defects (in-vivo samples as a comparison group are inaccessible, results can be difficult to interpret. Nevertheless, targeted assessment of imprinted gDMRs in human cultured embryos has shown that aberrant imprinting could be present in >50% (Additional evidence that early epigenetic programming is susceptible to environmental factors comes from the study of pregnancy outcomes associated with ART. With the increase in ART use globally, there has been an extensive effort to evaluate whether procedures, such as ovarian stimulation, The recent advances in low-input technologies has provided novel insights into epigenetic dynamics during oogenesis and the earliest events of embryonic development in mice. Studies to date have revealed the unique epigenetic landscape of the oocyte, not only DNA methylation, but also histone modifications and nuclear organisation. Future work will continue to explore the underlying mechanisms and the functional importance of these non-canonical patterns. The evaluation of epigenetic profiles in the early embryo suggest that there is widespread erasure of gametic epigenetic patterns after fertilisation and subsequent re-establishment of DNA methylation, histone modifications, chromatin accessibility and nuclear organisation. While the mechanisms driving this reprogramming are unclear, it is apparent that there are localised exceptions, including both canonical and non-canonical imprinted regions.At present, the study of epigenetic reprogramming events in humans has been largely restricted to DNA methylation. In comparison to mice, there appear to be similar dynamics in both gametes and the early embryo, and yet the proteins modulating these dynamics are often divergent in timing or function. Thus, future investigations of epigenetic patterns in human development may not only reveal further novel regulatory mechanisms, but also differences in the extent of epigenetic information transmitted from gametes to embryos. These discoveries will be essential in understanding the influence of our environment on pregnancy and lifelong health of offspring.C.H. and H.D. reviewed the literature, wrote the manuscript sections and generated the figures. G.K. provided input into manuscript content and composition, revised the manuscript and financially supported this work.Grants from the UK Medical Research Council and Biotechnology and Biological Sciences Research Council awarded to G.K. supported this work.The authors have no conflicts of interest.


This review covers recent developments and trends in herbicide-resistant (HR) weed management in agronomic field crops. In countries where input-intensive agriculture is practiced, these developments and trends over the past decade include renewed efforts by the agrichemical industry in herbicide discovery, cultivation of crops with combined (stacked) HR traits, increasing reliance on preemergence vs. postemergence herbicides, breeding for weed-competitive crop cultivars, expansion of harvest weed seed control practices, and advances in site-specific or precision weed management. The unifying framework or strategy underlying these developments and trends is mitigation of viable weed seeds into the soil seed bank and maintaining low weed seed banks to minimize population proliferation, evolution of resistance to additional herbicidal sites of action, and spread. A key question going forward is: how much weed control is enough to consistently achieve the goal of low weed seed banks? The vision for future HR weed management programs must be sustained crop production and profitability with reduced herbicide (particularly glyphosate) dependency. Over the past decade, the most significant change in strategy in herbicide-resistant (HR) weed management globally has been the increased focus on reducing the weed seed bank and maintaining low seed bank levels by whatever means possible. During the 1960s to 1990s, much research was devoted to determining the effect of weed density and time of emergence relative to the crop on crop revenue (yield by price) loss. These results were used to develop models or decision-support systems for herbicide application. Those initial weed economic threshold models with a single crop season focus became more sophisticated by considering longer time periods and weed seed bank implications, i.e., economic optimum thresholds or injury levels ,3. TodayGlycine max (L.) Merr.], maize (Zea mays L.), and cotton (Gossypium hirsutum L.) [As detailed in the following sections, recent developments and trends related to HR weed management include renewed efforts in herbicide discovery by the agrichemical industry following a prolonged period from the late 1980s to present day when no new herbicide SOA was commercialized. In this intervening period, industry strategy has been to use existing chemistry for new, expanded uses by introducing single or combined (stacked) HR traits into our major agronomic crops, most notably soybean [utum L.) . AlthougAnother major trend related to herbicide usage is increasing prominence of preemergence (PRE) herbicides with soil-residual activity to fill the void left by postemergence (POST) products, such as acetyl-CoA carboxylase (ACCase) or acetolactate synthase (ALS) inhibitors, due to loss in efficacy because of widespread evolved resistance. Therefore, the pendulum is now swinging in the other direction. In the 1970s and 1980s, PRE herbicide application requiring soil incorporation dropped off markedly in favour of POST herbicide application more suited to low soil disturbance no-tillage cropping systems [Additionally, we review two non-herbicidal HR weed management developments—one already making a significant impact  and one potentially posed to do so in the near future (weed-competitive crop cultivars). Although research and development into site-specific weed management (SSWM) (or precision weed management) have been ongoing for over 20 years, the adoption of this technology in agronomic field crops is still very low despite the demonstrated economic benefits . NeverthHerbicides remain an essential component of integrated weed management (IWM) systems in conventional agriculture. During the 1950s to 1970s, a new herbicide SOA was frequently introduced into the marketplace (A key reason was the widespread adoption of glyphosate-resistant (GR) crops in the mid-1990s and concomitant increased use of glyphosate herbicide (Roundup™). Patent expiration in 2000 led to cheaper generic products and a marked increase in glyphosate usage. Glyphosate usage now surpasses that of any other herbicide SOA ,11. In aDiscovering, developing, registering, and commercializing a new herbicide is a risky and costly venture, approaching USD $300 million . On averOne promising direction is the discovery and development of novel herbicides based on products that are by-products of microorganisms or extracts of plants . ResearcSoybean in the United States (U.S) perhaps best illustrates the changing adoption of cultivars with different HR traits . The plaThe dominant trait is still GR. The original Roundup Ready (RR) soybean went off patent in 2015. In 2009, RR2 soybean were introduced into the market. Although Bayer is transitioning to the RR2 Xtend (dicamba resistance) platform, many seed companies still sell RR2 cultivars. Currently, cultivars with the sole RR trait account for 30% of the U.S. market. The GR cultivars with the Xtend trait are expected to reach close to 50% of market share in 2019. This high adoption rate of the Xtend trait in just three years reflects its importance to growers in managing GR and other HR weeds. However, the dicamba herbicides  registered for use in these soybean cultivars are classified as a ‘restricted use pesticide’ by the U.S. Environmental Protection Agency. Therefore, they can only be sold to, and used by certified applicators in an effort to reduce potential injury to sensitive cultivars or crops due to off-target movement.Amaranthus spp. This increased market share is also the result of lower seed prices in recent years and the availability of generic glufosinate herbicide products. Soybean cultivars with the combined RR+LL and RR+LL+dicamba (Xtend flex) traits are also available.The LibertyLink™ (LL) soybean system, introduced in 2009, confers resistance to glufosinate (Liberty™) herbicide. In the merger with Monsanto, the technology was divested by Bayer to BASF (Credenz™ soybean platform). As with the RR2 Xtend soybean system, the LL system has been gaining market share over the past five years (currently about 20%) due to the need to manage the increasing incidence of GR weeds such as Going forward, GT27 soybean, developed by MS Technologies, Bayer and Mertec LLC, confer tolerance to glyphosate and isoxaflutole, an hydroxyphenyl-pyruvate-dioxygenase (HPPD)-inhibiting herbicide . BASF inOryza sativa L.) was a consideration impacting the introduction of transgenic cultivars. Crops such as canola that are grown on a relatively small area globally are of lesser priority for investment in new HR-trait cultivars. Monsanto abandoned plans to commercialize GR wheat (Triticum aestivum L.) in 2004 largely because of lack of market acceptance of transgenic cultivars. Therefore, soybean, maize and cotton will continue to be the tier-1 level for investment, development, and introduction of stacked-HR trait cultivars.A company’s decision to develop and introduce an HR trait for a particular crop depends primarily on the prospect for regulatory approval, market size , future market access, and grower demand . For example, frequent outcrossing between rice and related weed, red rice (With the rapid transition towards soybean and other crop cultivars with stacked (two- and three-way) HR traits, it will become more challenging for growers to choose the right system or systems to control HR and non-HR weeds on their farm. Comprehensive training for growers in proper stewardship practices of these technologies will be critical to optimizing and prolonging their benefits and minimizing risks as they are repeatedly and widely deployed across millions of hectares of cropland annually. Seed retailers and agronomists also require professional development training in this area as they often advise and influence a grower’s decision regarding herbicide options best tailored to their specific weed problems.Over the past decade, there has been increasing reliance on preplant or PRE herbicides with short to long soil-residual activity to manage weed populations resistant to glyphosate and many POST herbicides such as ACCase or ALS inhibitors. For example, the use of preplant and PRE herbicides in U.S. soybean from 2000 to 2015 increased from 25 to 70% of crop area, largely in response to GR weeds . The PRECicer arientum L.; lentil, Lens culinaris Medik.) with slow early-season growth and development or slow canopy closure. To proactively or reactively manage HR weeds in a growing season, the recommended herbicide treatment program should ideally comprise multiple SOAs applied as needed during one or more application windows  in mixtures or in sequence as required [Ideally, PRE herbicides will control weed cohorts very early in the growing season, thereby lessening potential crop yield loss due to weed competition and the selection pressure for resistance evolution from any in-crop (vegetative stage) or pre-harvest herbicide treatments that may still be required for acceptable season-long weed control. A PRE herbicide application is especially important for wide-row crops   or pulserequired ,28. Lolium rigidum Gaud.) control in wheat in Australia. Traditionally, it was advised that growers should delay sowing in fields with high weed densities to maximize weed control before sowing and reduce the seed bank by the use of glyphosate or paraquat prior to sowing [S-metolachlor, triallate, or pyroxasulfone. Growers are advised to integrate PRE herbicide application with multiple, effective cultural practices that optimize herbicide efficacy and crop suppression of weeds. With traditional delayed seeding to facilitate preplant weed control, weeds that establish in these late-sown winter crops can be more competitive due to the reduced crop growth rate associated with reduced soil and air temperatures. With the availability of highly-effective PRE herbicides that control initial weed cohorts, early seeding may be the best strategy to reduce weed seed production, as later germinating cohorts are suppressed by a larger crop canopy [One case study that exemplifies this trend towards PRE herbicide usage is annual ryegrass  and its impact on the distribution of soil organic carbon (organic matter) and texture  in the soil profile. A basic knowledge of the physical and chemical properties of each herbicide is needed to understand how it will likely behave in the soil environment of a grower’s field. Because these herbicides may be applied a few days before seeding or at the time of seeding (soil incorporation by sowing), the type of seeding equipment and operational parameters can affect PRE herbicide spatial  distribution, which, in turn, is influenced by water distribution and abundance in the soil profile. When PRE herbicide application occurs in dry soil, research is needed to better understand the interaction between time of PRE herbicide application and time of rainfall (or time of seeding) in terms of crop injury and weed control efficacy. Additionally, more research is needed on agronomic practices that optimize the effectiveness and utility of PRE herbicides in conservation-tillage systems, such as crop seeding rate, row spacing, and fertilizer placement and timing.Crop competitiveness against weeds is an important pillar of IWM and therefore HR weed management ,34. WeedHordeum vulgare L.)) cultivars will become increasingly available to growers over the next decade [With the continual increase in incidence and complexity of herbicide resistance in weed populations and declining availability of effective herbicide tools, plant breeders are now researching and developing germplasm with enhanced weed competitiveness  of crop growth vigour, such as percentage ground cover, canopy closure, or leaf area index. A first step, however, is validation of such assessments through controlled environment experiments on relative growth rates as well as small-plot experiments (weedy and weed-free conditions) measuring key parameters correlated with crop competitiveness . FurtherHWSC is now an established, widely adopted weed management tool used by Australian grain growers following extensive research, development, and extension efforts. Various HWSC practices can greatly reduce the viability of weed seeds in the chaff fraction emitted by a combine harvester. These HWSC practices include the following : (1) naRaphanus raphanistrum L.) meet both criteria well. In the last five years, substantial research and development efforts have been conducted in Canada and the U.S. to evaluate the potential of HWSC for key troublesome weed species, such as wild oat (Avena fatua L.) and cleavers  in the Great Plains [Amaranthus palmeri S. Watson) and barnyardgrass (Echinochloa spp.) in the Midwest or southern U.S. [Alopecurus myosuroides Huds.), despite substantial seed shatter before harvest, and other economically important weed species.Weed species most amenable to HWSC practices are those that retain their seeds in sufficient quantities until harvest  at a plant height (ca. 15 cm or higher) suitable for collection by the combine harvester. In Australia, two of the most problematic weeds, annual ryegrass and wild radish . In EurOngoing field evaluation of different HWSC practices in different cropping systems across North America and elsewhere will facilitate grower awareness and future adoption of this important non-herbicidal weed management tool. An equally important consideration in these evaluations is the monitoring of weed species shifts over time as an inevitable consequence of the varying efficacy of HWSC practices on different weed species. In addition, weed populations may quickly adapt to recurrent HWSC practices in a field. Such adaptation may include earlier flowering and seed maturity, reduced seed retention on the plant, or plants that reproduce below harvest cutting height . As with> 80% efficacy as typical for most herbicides. Therefore, HWSC is just one component of an IWM system, which ideally comprises combined (stacked) effective non-herbicidal practices that provide synergistic suppression of weed growth and fecundity.Similar to herbicides, HWSC is not a stand-alone tool for weed management. Even on weed species well suited to seed capture or destruction at harvest such as annual ryegrass, weed control efficacy averages about 60% , not > 8There is much hype surrounding ‘digital’ or ‘precision’ agriculture in relation to yield mapping, fertilizer application, etc. Currently, SSWM is mostly used in high-value, irrigated, traditionally labour-intensive horticultural crops . To date-1 to efficiently process and analyze large amounts of generated data [Today, real-time weed control in fallow fields  is becoming more widespread in semi-arid to arid cropping regions . Herbicited data ,52. Realted data . Weeds often are not distributed evenly within fields, but tend to occur in patches of varying size, shape and density . Weed paA first step in an elementary SSWM approach could be the creation of a weed map at crop maturity or time of harvest, using a global positioning system (GPS) unit mounted on a tractor or combine harvester. Such a map can be created manually  or via mounted sensors with accompanying datalogger. Such sensors could include cameras, such as RGB  or multispectral/color-infrared (3–7 bands around 100-nm width in the visible and infrared region); structure from motion; or light detection and ranging (LiDAR) system . Such a Seeding and spraying farm equipment are becoming increasingly capable of the variable rate application of inputs. Therefore, these weed patches could be targeted with greater crop seeding rates or highly effective herbicide treatments. Further research is needed to expand the use pattern of effective herbicides to enable label registration. As weed distributions would be mapped annually, growers would be able to continually adapt to changing weed distributions or newly evolving HR weed patches. With supporting research and development, this simple initial approach to SSWM may bridge the grower implementation disconnect that has characterized SSWM. The challenge for researchers is to work with growers and their agronomists and advisers to demonstrate (1) how existing technology can be adapted and used to easily and reliably map and manage weed patches in fields; and (2) sufficient return on investment. Grower experience and confidence gained using a relatively simple SSWM system may be an invaluable prerequisite for future adoption of more technologically-advanced real-time SSWM systems.The history of HR weed management globally shows that growers deal with the problem after it occurs, not before . Further-1). Standardized methodology can be utilized to better assess the economic feasibility, impact, and consequences of reduced pesticide use [The vision for the future of HR weed management globally should center on reduced herbicide dependency, especially glyphosate. Non-herbicidal alternatives are often adopted to compensate for reduced herbicide efficacy due to increasing incidence of resistance, rather than as a partial replacement for herbicides . The metcide use . To adeq


This review presents a selection of regulatory molecules of tumor microenvironmental properties and metastasis. Signaling pathways controlling mesenchymal biology in bone and soft-tissue sarcomas found in children and adolescents are prioritized.The tumor microenvironment of pediatric tumors is still relatively unexplored. Highlighted findings are mainly on deregulated genes associated with cell adhesion, migration, and tumor cell dissemination. How these processes are involved in a mesenchymal phenotype and metastasis is further discussed in relation to the epithelial to mesenchymal transition (EMT) in epithelial tumors. Cell plasticity is emerging as a concept with impact on tumor behavior.Sarcomas belong to a heterogeneous group of tumors where local recurrence and tumor spread pose major challenges despite intense multimodal treatments. Molecular pathways involved in the metastatic process are currently being characterized, and tumor-regulatory properties of structural components, and infiltrating, non-malignant cell types should be further investigated. Pediatric tumors typically present with an overall low mutational burden but often with recurrent chromosomal aberrations ••. DetecNumerous studies have by now elegantly illustrated how activated non-malignant stromal cells control matrix stiffness; become contractile and pro-invasive , 4; and How metastatic spread of pediatric tumors is controlled by the tumor microenvironment is still an early field of research. Common sarcoma subtypes of childhood include osteosarcoma, Ewing sarcoma, and rhabdomyosarcoma. The prognosis of these tumors is relatively favorable compared to many sarcomas in adults, but metastatic spread is still problematic. Osteosarcoma principally originates from bone and is likely the subtype where the tumor microenvironment has been most characterized. Ewing sarcoma arises in either bone or soft tissue, whereas rhabdomyosarcoma is a soft-tissue sarcoma displaying signs of a myogenic program with skeletal muscle features. Recent findings from mainly these three pediatric sarcomas provide the basis for this review on the tumor microenvironment and mesenchymal mechanisms regulating cell migration and metastasis.Bone sarcomas are generally characterized by pain, whereas a painless mass is more common in soft-tissue sarcomas. A palpable mass may or may not be present in bone tumors. Constitutional symptoms such as malaise, wasting, or generalized signs of inflammation with fever are only occasionally observed if the tumors are large and necrotic , 7. In sRhabdomyosarcomas and Ewing sarcomas are high-grade tumors, whereas osteosarcomas can be of high grade or low grade. Staging is based on the TNM or the musculoskeletal tumor society system, and the clinical group system is applicable in rhabdomyosarcoma , 9. AbouThe three major types of pediatric sarcomas have a similar pattern of metastasis, with hematogenous spread as the classic route of dissemination. Lungs are the most prominent metastatic site, thereafter bone and bone marrow. Less common sites are lymph nodes , viscera, and soft tissues , 11. TheModern treatment regimens include early systemic chemotherapy to eradicate micrometastatic disease. This is combined with local excision of the primary tumor and macrometastases when feasible. Most patients are given neoadjuvant chemotherapy for local disease control and continue with additional cycles of chemotherapy after surgery , 12, 13.EWS-ETS gene fusion variants are found in Ewing sarcomas, and similarly, the most common fusion genes associated with alveolar rhabdomyosarcoma are PAX3-FOXO1 and PAX7-FOXO1. Accordingly, the two major subtypes of rhabdomyosarcoma, with the alveolar subtype being more aggressive, are with some exceptions distinguishable with modern techniques. However, even though embryonal rhabdomyosarcomas typically develop earlier along the developmental program compared to the alveolar subtype, they remain clinically and molecularly indistinguishable from fusion gene-negative alveolar rhabdomyosarcomas [Detection of tumor-specific translocations is often diagnostically useful in pediatric sarcomas . EWS-ETSsarcomas ••, 16.The prognosis of pediatric sarcoma is dependent on a series of factors, including size and site of the primary tumor and age of the patient , 17, 18.When tumor cells initiate the multistep process of metastasis, they have begun a journey where adaptation to foreign tissue microenvironments is essential for survival. There are still many unknowns about selection processes during disease progression, where only some sarcoma cells reach anatomically distant organs and successfully metastasize. The discussion below is focused on mesenchymal cell plasticity and cell adhesion molecules involved in cell migration and metastasis. Notably, mesenchymal properties in sarcoma are regulated by multiple developmental signaling pathways, and some of these were recently reviewed elsewhere .Cell migration can be broadly categorized as collective cell migration  or individual cell migration (sarcoma). The mesenchymal cell migration of sarcomas can involve both single cells or cells in chains and is typically regulated by the extracellular matrix (ECM), various integrins, and proteases. Cadherins, which form adherens junctions, are broadly implicated in direct cell-cell contacts in multicellular organisms. Mesenchymal adherens junctions are expected to be more transient compared to the epithelial counterpart, and the stability is partly controlled by endocytosis and regulation of the cytoskeleton.It is well known that downregulation of E-cadherin is essential during the cellular program of epithelial to mesenchymal transition (EMT), and its upregulation is conversely linked to the mesenchymal to epithelial transition (MET) during establishment of distant metastasis. A mesenchymal to amoeboid transition (MAT) has also been described in osteosarcoma during transendothelial migration •. RecentThe process of EMT in sarcoma is by definition less obvious, but E-cadherin expression is also here known to reduce anchorage-independent growth and spheroid formation •. The tiCadherin switching and induced expression of the EMT marker N-cadherin is associated with morphological changes toward a mesenchymal phenotype with migratory and invasive properties in malignant cells of epithelial origin. Similar mechanisms have also been reported in mesenchymal malignancies. For example, induction of N-cadherin and alpha9-integrin increases cellular invasion in a Notch-dependent manner in rhabdomyosarcoma . Notch sBy now, there are numerous publications on disease-regulatory roles of epithelial and mesenchymal markers involved in cell movements in pediatric sarcoma. Preussner et al. recently explored the importance of epithelial/mesenchymal states in the context of tumor cell plasticity in a genetic mouse model of rhabdomyosarcoma ••. In a Invasive properties of primary tumors may not always imply a capacity to establish distant metastases followed by decreased overall survival. A recent EpSSG study demonstrated that small pulmonary nodules at diagnosis could be present in over 20% of otherwise localized rhabdomyosarcoma, but these nodules were not found to impact survival . ClearlyThe traditional linear progression model of metastasis is based on the assumption that genetic mutations accumulate in the tumor over time, and eventually, subclonal populations acquire metastatic features. Compelling evidence instead favors an early dissemination process, with more effective colonization, and pathways of parallel progression . This laRegardless of whether dissemination occurs early or late during tumor progression, it also involves different anatomic locations for metastatic outgrowth in a tumor type-specific manner. The organotropic model of metastasis describes how organ tropism or pre-metastatic niches facilitate successful metastasis according to a modified notion of the classic seed and soil hypothesis, where certain tumor cells (seed) have an affinity for the milieu (soil) of certain organs . In contThe sarcoma tumor microenvironment can vary extensively with subtype, anatomic location, age, gender, genomic complexity, and prior treatment. Molecules of relevance from a mesenchymal stroma perspective are reviewed below with a particular focus on those regulating cellular transition states and migration in pediatric sarcoma  and matricellular proteins (such as osteopontin) provide support and signaling cues of importance for cell movements. Several ECM-associated proteins are regulated by transforming growth factor beta (TGFβ) and act as potential biomarkers . A uniquA hypoxic tumor microenvironment generally contributes to tumor progression, and the impact of intratumoral oxygen gradients has been studied in sarcoma cell invasion . HypoxiaCXCR4 expression is detected in 67% of osteosarcomas and correlates with vascular endothelial growth factor (VEGF) expression and decreased patient survival , 55. A cConvincing work from Weaver and others have with time contributed to an increased basic understanding about how matrix stiffness and physical environments around cancerous cells matter for tumor progression . In sarcEWS-FLI oncoprotein downregulates LOX and the reported tumor-suppressive activities have been linked to a propeptide domain [This can be exemplified by lysyl oxidases (LOX), which are considered to be powerful regulators of structural modifications in normal connective tissue, fibrotic disease, and cancer. The LOX family consists of catalyzing enzymes involved in cross-linking of collagen and elastin in the tumor microenvironment. By now, numerous studies have demonstrated an active role of LOX family members in tumor progression and metastasis in tumor types of different origin. There are also reports on tumor-suppressive activities, for example in osteosarcoma . In Ewine domain . Both LOThrombospondin-1 (TSP1) represents a classic example of a glycoprotein in the tumor microenvironment and is commonly recognized for its anti-angiogenic functions and impact on tumor cell invasion via multiple cell surface molecules and matrix metalloproteinase interactions , 64. ItsCell proliferation and differentiation are often tightly linked processes and regulated by growth factors such as TGFβ, platelet-derived growth factor (PDGF), and fibroblast growth factor (FGF) in mesenchymal stem cells . TGFβ isMembers of the TGFβ family act on different cell types in the tumor microenvironment. The TGFβ co-receptor endoglin is for example considered to be a vessel marker in tumor biology but is also expressed by malignant cells and has been linked to tumor cell plasticity and worse patient survival in Ewing sarcoma . Other TThe TGFβ pathway also participates in the selective suppression of the immune system , 86. OstAnother developmental signaling pathway that is potentially activated during sarcomagenesis is the PDGF pathway. Recently, PDGF signaling was shown to play a role in maintaining cancer stem cell phenotypes such as self-renewal, invasion, and chemotherapy resistance in sarcoma , 90•. HiPAX3-FOXO1 , and EWS-ETS (Ewing sarcoma) are both examples of fusion genes with capacity to experimentally induce expression of PDGF family members [In general, members of the PDGF family can be linked to primary tumor growth, metastasis, drug resistance, and poor clinical outcome in malignances of different cellular origin, but the role of PDGF activity in different sarcoma subtypes remains unclear . Genetic members , 100.Notably, identified resistance mechanisms to therapeutic agents in sarcoma have included deregulated PDGF signaling. A recent example of this is the reported feedback interaction between CXCR4 and PDGF signaling in Ewing sarcoma, where high expression of CXCR4 correlates with metastasis and poor patient survival , 102•. WOncologic treatment of pediatric sarcomas has classically relied on chemotherapy. Various agents have been used, and these have in common the preferential cytotoxicity against the malignant cells of the primary tumor and any metastatic site. We are now entering a new era in oncology, mainly characterized by the introduction of combination treatments and targeted therapy directed against malignant cells and/or cells of the tumor microenvironment. Such examples include imatinib for dermatofibrosarcoma protuberans and gastrointestinal stromal tumors and pazopanib for metastatic non-adipocytic soft-tissue sarcoma .Other novel sarcoma treatments include trabectedin, which has been approved by the European Medicines Agency (EMA) for treatment of soft-tissue sarcomas in adults. Apart from direct activity on malignant cells, trabectedin modulates the phenotype of tumor-associated macrophages. Another EMA-approved treatment regimen targeting macrophages is muramyl tripeptide (mifamurtide), which is used for treatment of osteosarcoma. Immunotherapy has recently emerged as a promising strategy to modulate immune cell activity in subsets of patients but is still under early investigation in sarcoma. Therapeutic modification of the immune response in the pediatric sarcoma microenvironment is also explored using tumor vaccines. How effective such treatments would be remains to be determined.An increased understanding about tumor microenvironmental activities in pediatric sarcoma progression is essential for improving patient outcome and quality of life. Studies in common cancers of epithelial origin have been useful in the identification of candidate molecular pathways involved in metastasis and therapeutic resistance in sarcoma. However, the mesenchymal origin of sarcomas makes them unique and cellular processes like EMT and MET cannot be discussed in the same manner as in epithelial tumors. The heterogeneity between, and within, sarcoma subtypes is also particularly challenging. Consequently, how findings from other settings can be translated to pediatric sarcoma remains to be further explored.