To assess the efficacy and tolerability of oral aprepitant, a substance P/neurokinin A receptor antagonist, in controlling nausea associated with IV dihydroergotamine (DHE) administered for medically refractory migrainous headache in patients not responding to standard antiemetics or with a history of uncontrolled nausea with DHE.International Classification of Headache Disorders, 3rd edition (beta version). Peak and average daily nausea scores from hourly diaries, or daily entries of notes, and concurrent antiemetic use were collected and tabulated.This was a retrospective chart review of prospectively collected hourly diary data and clinical notes of patients hospitalized between 2011 and 2015 for inpatient treatment with DHE. Patients were classified using the Seventy-four patients, of whom 24 had daily diaries, with chronic migraine with or without aura, with or without medication overuse, or new daily persistent headache of a migrainous type, were identified. In 36 of 57 cases in which aprepitant was administered during hospitalization, there was a 50% reduction in the average daily number of as-needed antinausea medications. Of 57 patients, 52 reported that the addition of aprepitant improved nausea. Among 21 of 24 patients with hourly diary data, nausea scores were reduced and in all 12 with vomiting there was cessation of emesis after aprepitant was added. Aprepitant was well tolerated with no treatment emergent adverse events.Aprepitant can be effective in the treatment of refractory DHE-induced nausea and emesis. Given the broader issue of troublesome nausea and vomiting in acute presentations of migraine, general neurologists may consider what place aprepitant has in the management of such patients.This study provides Class IV evidence that for patients with medically refractory migraine receiving IV DHE, oral aprepitant reduces nausea. Aprepitant is a selective, high-affinity substance P/neurokinin-1 (NK1) receptor antagonist, which mitigates the emetic effects of substance P.4 Aprepitant has been used in the prevention of postoperative and chemotherapy-induced nausea and vomiting.5 In patients for whom conventional antiemetics were not effective, we began to use aprepitant and here report our experience with this novel approach to DHE-associated nausea.Typically, premedication regimens used to prevent DHE-associated nausea, or indeed nausea more generally in migraine, target dopamine, serotonin 5-hydroxytryptamine  from June 1, 2011, through April 17, 2015, and received oral aprepitant as antiemetic therapy due to refractory nausea, either at the onset of DHE administration or later during their treatment course. The primary research question was whether aprepitant reduced nausea in patients receiving DHE for the treatment of medically refractory migraine. Aprepitant was given as a loading dose of 125 mg on day 1 and thereafter at 80 mg daily 30 minutes before the first daily dose of DHE.The review was approved by the institutional review board of the University of California, San Francisco (12-09318).Peak and average daily nausea scores were determined before and after aprepitant administration from patients' hourly diaries, whereby headache and nausea were rated on an 11-point visual analog graph, or with daily progress notes, or both. Daily medication administration records were reviewed for other concurrent antiemetic medications given either as standing premedications or as-needed doses for breakthrough nausea.The efficacy of aprepitant was assessed by determining reduction (>50%) in either average or peak daily nausea score (1 point), cessation of emesis following administration of aprepitant, and ≥50% reduction in the average daily number of as-needed antinausea medications. In addition, patients were surveyed for their subjective impression regarding the effectiveness of aprepitant in controlling nausea, vomiting, or both with an open-ended question.Patient daily notes and diaries were reviewed for an assessment of any adverse events and to determine tolerability during inpatient use.Data were abstracted from patient hourly diaries or medical records into a summary spreadsheet . Summary data are presented as proportions observed. Given the exploratory nature of the work, the add-on nature of the treatment, and the absence of a suitable control, we did not have a formal aim for hypothesis testing.6Seventy-four cases were identified  with admIn 57 of these cases, aprepitant was administered midway through the IV DHE protocol for nausea that was refractory to other standing premedication antiemetics, including IV ondansetron, granisetron, oral domperidone, or IV promethazine. In the remaining 17 cases, aprepitant was initiated on admission because of the presence of severe nausea at baseline or known history of severe nausea with prior DHE treatment. Inpatient diaries recording hourly nausea scores were available for review in 24 of the first 57 cases.Mean or peak daily nausea scores, or both, were reduced following administration of aprepitant in 21 of the 24 patients (88%) whose diaries were available for review. Vomiting occurred in 12 patients before receiving aprepitant and ceased in all 12 cases post aprepitant. One patient developed emesis only after aprepitant was added.Among 36 of the 57 patients (63%) who received aprepitant midway through hospitalization, there was a ≥50% reduction in the average daily number of as-needed antinausea medications post aprepitant. Finally, 52 of the 57 patients (91%) reported subjective improvement of their nausea following the addition of aprepitant. Two reported no benefit and data were unavailable for the remaining 3 patients.Among the patients who received aprepitant at the onset of the DHE protocol (n = 17), 6 patients (35%) did not require any as-needed antinausea medications throughout the entire 5-day hospitalization. In these cases, other standing premedication nausea treatments given in addition to aprepitant on admission included ondansetron with domperidone (n = 4) or granisetron with domperidone (n = 1). Aprepitant was the sole premedication agent given in 1 of the 6 cases not requiring additional as-needed medications.We noted a subgroup of patients withdrawn from daily cannabis use during their hospitalization for inpatient DHE (n = 7). Nausea was noted to be particularly severe in these cases, and refractory to domperidone and IV ondansetron. All patients demonstrated a response in at least 2 of the 3 outcome measures with addition of aprepitant.No adverse effects that could be attributable to aprepitant were reported by any of the 74 patients who received the medication. The medicine was extremely well-tolerated.3 receptor antagonists, and antihistamines, have failed. Moreover, aprepitant can be effective in patients with marked nausea before DHE administration and in patients with a history of DHE-induced nausea. A distinctive subgroup of patients with refractory nausea withdrawing from daily cannabinoid agonist use also respond well to aprepitant. While comparative efficacy studies would be appropriate to ascertain which is the best initial antiemetic path when using DHE, our data support the addition of aprepitant in patients whose conventional antiemetics failed or in those with special cases likely to be refractory to conventional antiemetics. Moreover, given the very common occurrence of nausea and vomiting in patients with migraine attending emergency departments and the excellent tolerability of aprepitant including a lack of sedative effects, its broader use could be considered in such settings.These data demonstrate that aprepitant can provide relief of DHE-induced nausea and emesis where standard strategies, such as dopamine receptor antagonists, serotonin 5-HT7 Nausea in association with administration of DHE is well recognized1; it has been suggested that its control is associated with better medium-term efficacy outcomes.3 Frequently used antiemetic medications in the context of DHE include ondansetron and granisetron (5-HT3 receptor antagonists), metoclopramide (dopamine D2 receptor antagonist), promethazine (primarily H1 and muscarinic acetylcholine receptor antagonist), prochlorperazine (primarily D2 receptor antagonist), and domperidone . While domperidone and the 5-HT3 receptor antagonists are very well tolerated when used conservatively, metoclopramide, prochlorperazine, and promethazine are not without their own adverse events that can complicate the inpatient management of migraine. Despite vigorous treatment, some patients may develop significant nausea resulting in dose adjustments of DHE or premature termination of treatment with diminished efficacy.8 Aprepitant was developed for cancer therapy–induced emetogenesis9 and thus offers a novel approach to DHE-induced refractory nausea.DHE has been used in the treatment of migraine for many years.1 receptor, which is found in vagal afferent nerves within the gastrointestinal tract and in regions of the CNS that are involved in control of the vomiting reflex: the nucleus tractus solitarius and area postrema.4 Aprepitant is a potent NK1 receptor antagonist.5 Human PET studies show that aprepitant crosses the blood–brain barrier and acts on NK1 receptors, with minimal affinity for NK2 and NK3, serotonin 5-HT3, dopamine, or corticosteroid receptors.10 In clinical use, aprepitant is very well tolerated with generally mild side effects reported in cancer studies.9 Two notable drug interactions are that barbiturates may reduce aprepitant blood levels and aprepitant may induce estrogen metabolism, thereby affecting contraception in the menstrual cycle in which it is used.Substance P is a peptide of the neurokinin family, active at the NKAn important limitation of this report is the lack of blinding or a contemporaneous control group. Given the data we now have, a blinded study is feasible. The use of placebo is more complex since aprepitant is an established agent for nausea and emesis, albeit in cancer. Comparative efficacy studies are certainly possible, such as comparing ondansetron and aprepitant.Herein, we provide data suggesting that aprepitant can be effective in DHE-induced nausea and emesis where usual treatment had failed, even in patients withdrawing from cannabinoids. Given the excellent tolerability of aprepitant, it seems reasonable to consider its use in refractory DHE-induced nausea and emesis, in particular, and more broadly in migraine-associated nausea and vomiting.


Coccidioides, the causative fungi, typically is associated with soil-disrupting activities , even those not engaged in soil-disruptive work, might be at risk for coccidioidomycosis.In March 2013, the California Department of Public Health (CDPH) identified two Doctor’s First Reports of Occupational Injury or Illness (DFRs)Review of DFRs for coccidioidomycosis diagnoses initially identified two patients who worked for the same employer and listed work-associated coccidioidomycosis as the claimed illness. Patient 1, an actor, sought evaluation at an emergency department on February 28, 2012, after a 2-week history of fever and cough. Patient 1 had received a letter from his employer dated February 17, 2012, stating that a member of the cast or crew present at an outdoor filming event during January 17–19 in Ventura County had a diagnosis of coccidioidomycosis; patient 1 had also worked at this filming event. A copy of the letter sent to the employee was included with the DFR. Patient 2, a camera operator who had sought evaluation at an emergency department on February 24 after a 2-week history of cough, joint aches, and muscle pain, was identified by review of the health-care provider’s notes as having worked at the same outdoor filming event; patient 2 was not the patient referenced in the original letter.Subsequent review of information obtained from the California Department of Industrial Relations (DIR) identified six additional workers with the same employer who had sought evaluation for possible work-associated coccidioidomycosis. Because all workers identified were residents of Los Angeles County, CDPH informed LACDPH of the possible outbreak, and LACDPH led the local investigation.A confirmed outbreak case was defined as a laboratory-confirmed illness  meeting the 2011 Council of State and Territorial Epidemiologists coccidioidomycosis surveillance case definition  that occEight patients initially were identified through review of DFRs and information obtained from DIR. One was identified by review of social media, wherein the patient had posted details about his hospitalization, and one was identified by another patient as a relative (nonemployee) who had been onsite during the filming event. The patient referenced in the employer letter was among those with laboratory-confirmed illness. Of 10 persons identified, seven were interviewed; three could not be contacted. LACDPH ascertained five confirmed and five probable cases. The employee roster indicated 655 workers were associated with that particular television episode. The attack rate for all identified cases was 1.5%.Median time to symptom onset was 11 days (range = 3–28 days), as determined by interviews of seven patients and medical record review for two patients ; an estiCoccidioides exposure onsite. CDPH also advised the site owner to consult the local air pollution control district for assistance in mitigating offsite dust.The employer responded promptly to the initial identification of one illness among cast and crew by sending the original letter to employees, encouraging anyone with symptoms to seek medical evaluation. After interviewing the employer’s environmental health and safety manager and discussing future prevention practices, CDPH provided a “Preventing Work-Related Coccidioidomycosis ” fact sheet  to the eThe outbreak described in this report was identified by review of DFRs, using a pilot occupational coccidioidomycosis surveillance system recently established by CDPH. Title 17 of California’s Code of Regulations requires health-care providers to report coccidioidomycosis diagnoses and outbreaks to the local health jurisdiction . AlthougCoccidioides-endemic areas. Although most patients did not engage in soil-disruptive activities, substantial soil disruption immediately preceded the filming event, and the site owner reported ongoing dust intrusion from a neighboring mining company onto the filming site. Because no reliable methods for environmental Coccidioides sampling are available, identifying the source of the spores was not possible. CDPH previously had recommended a comprehensive approach to reducing incidence and severity of work-associated coccidioidomycosis  covering spoils piles and wetting disturbed areas, 2) establishing criteria for suspending work on the basis of wind and dust conditions, and 3) prompt disease recognition and referral to occupational medicine clinics for evaluation, treatment, and follow-up . Employees working outdoors in any industry, even those not actively engaged in soil disruption, might be exposed to What are the implications for public health practice?Coccidioides is endemic, including worksites of industries and occupations not typically associated with soil-disrupting activities. Health-care providers should consider the possibility of work-relatedness among patients with coccidioidomycosis diagnoses and note employer, work location, industry, and occupation when reporting cases.Occupational injury and illness surveillance can identify outbreaks not otherwise detected by traditional infectious disease surveillance. Education about coccidioidomycosis, including signs and symptoms, and exposure prevention measures should be implemented at outdoor worksites in areas where


The human brain generally remains structurally and functionally sound for many decades, despite the post-mitotic and non-regenerative nature of neurons. This is testament to the brain’s profound capacity for homeostasis: both neurons and glia have in-built mechanisms that enable them to mount adaptive or protective responses to potentially challenging situations, ensuring that cellular viability and functionality is maintained. The high and variable metabolic and mitochondrial activity of neurons places several demands on the brain, including the task of neutralizing the associated reactive oxygen species (ROS) produced, to limit the accumulation of oxidative damage. Astrocytes play a key role in providing antioxidant support to nearby neurons, and redox regulation of the astrocytic Nrf2 pathway represents a powerful homeostatic regulator of the large cohort of Nrf2-regulated antioxidant genes that they express. In contrast, the Nrf2 pathway is weak in neurons, robbing them of this particular homeostatic device. However, many neuronal antioxidant genes are controlled by synaptic activity, enabling activity-dependent increases in ROS production to be offset by enhanced antioxidant capacity of both glutathione and thioredoxin-peroxiredoxin systems. These distinct homeostatic mechanisms in neurons and astrocytes together combine to promote neuronal resistance to oxidative insults. Future investigations into signaling between distinct cell types within the neuro-glial unit are likely to uncover further mechanisms underlying redox homeostasis in the brain. •Redox homeostasis is essential for brain health.•Homeostasis involves interactions within the neurogliovascular unit.•We describe cooperative contributions by neurons and astrocytes to redox homeostasis. Despite the well-documented increase in neuronal oxidative damage in the ageing brain, and the association of oxidative stress with several neurodegenerative disorders, the longevity of mammalian (particularly primate) neurons reflects successful redox homeostasis over many years. Understanding the basis for this illuminates a fundamental part of brain metabolism, points to key control nodes that may go wrong in disease, and also provides potential therapeutic targets for disorders associated with oxidative stress. The systems used inside the brain for neutralization of ROS or electrophilic xenobiotics are similar to those outside: the glutathione system, thioredoxin/peroxiredoxin system, superoxide dismutases, and catalase all play key roles in ROS neutralization and xeniobiotic adduction Many antioxidant genes in the systems outlined above are under the control of a master regulator of antioxidant defences, the transcription factor Nrf2, which binds to a promoter element called the antioxidant response element (ARE) present on these genes. Nrf2 is normally targeted for ubiquitin-mediated degradation by its endogenous inhibitor Keap1 2The first indication that the Nrf2-ARE pathway was particularly weak in neurons came from a study in neuronal and glial cells from the cerebellum The biological reason why Nrf2 is expressed so weakly in maturing neurons may be that it promotes weaker antioxidant defences to facilitate redox signaling involved in neuronal development Despite the brake that Nrf2 puts on neuronal development, it remains an open question as to whether re-activation of the Nrf2 pathway once neurons have matured, may be a useful way of boosting neuronal antioxidant defences. De-repression of the Nrf2 promoter can be achieved partly by treatment with a histone deacetylase inhibitor 3Neurons in isolation have long been known to have limited intrinsic antioxidant defences: they express relatively low levels of catalase and do not contain high levels of GSH Neurons are metabolically highly active, and consume large amounts of ATP simply to maintain their resting membrane potential. Neurons have relatively low glycolytic capacity and limited scope to upregulate it upon increased energy demand Nevertheless, despite their relatively low intrinsic antioxidant defences, it is self-evident that post-mitotic central neurons survive and are functional for many decades. The explanation for this apparent paradox is that neurons receive strong antioxidant support from surrounding glial cells, particularly astrocytes 2+-permanent subtype of ionotropic glutamate receptor Moreover, since oxidative stress also induces Nrf2-dependent gene expression in astrocytes, including GSH pathway genes The demonstrably potent capacity of astrocytes to confer non cell-autonomous neuroprotection against oxidative insults points to the translational potential of small molecule Nrf2 activators. Indeed, there exists a wide range of these which have shown neuroprotective effects in variety of models of acute and chronic neurological disorders, including stroke, and Alzheimer’s, Parkinson’s and Huntington’s diseases, as well as MS Clear proof that astrocyte-driven Nrf2 activity is sufficient to confer neuroprotection in vivo has however been provided through the generation of transgenic mice over-expressing Nrf2 specifically in astrocytes, and tested against models of a variety of neurological and neurodegenerative disorders including Parkinson’s disease, Huntington’s disease, Alexander disease and ALS 4Although the astrocytic supply of precursors for GSH synthesis to neurons represents a key factor in enabling neurons to neutralize ROS, it is not the only determinant. Neurons must be able to use these precursors to synthesize GSH, as well as possess the systems to utilize and recycle GSH, as well express other important intrinsic antioxidant systems such as those based around thioredoxin and peroxiredoxins Interestingly, however, many GSH pathway genes and other known Nrf2-regulated antioxidant genes such as Gclc, Gsr, Srxn1 and xCT are dynamically regulated in neurons by synaptic activity 5A consequence of neuronal antioxidant genes being activity-responsive is that synaptic activity can increase the capacity of neurons to utilize the support provided by astrocytes. In other words, while astrocytes are an important source of cysteine-containing precursors that neurons take up and use to make their own GSH, by increasing the GSH biosynthetic capacity of neurons, neuronal activity makes them better able to use these astrocyte cysteine-containing precursors to boost their intrinsic defences. As described above, astrocytic support is under control of the Nrf2 pathway. Thus, while the activation of astrocytic Nrf2, and the induction of synaptic activity, are separately neuroprotective, combined they have an additive effect on the resistance of neurons to oxidative insults One outstanding question, however, surrounds whether the influence of synaptic activity on antioxidant gene expression is limited to neurons. As noted above, exogenous activation of astrocytic NMDA receptors can activate Nrf2, raising the possibility that neuronal glutamate release could control astrocytic Nrf2


Sesame is a survivor crop cultivated for ages in arid areas under high temperatures and limited water conditions. Since its entire genome has been sequenced, revealing evolution, and functional characterization of its abiotic stress genes became a hot topic. In this study, we performed a whole-genome identification and analysis of Hsf gene family in sesame. Thirty genes encoding Hsf domain were found and classified into 3 major classes A, B, and C. The class A members were the most representative one and Hsf genes were distributed in 12 of the 16 linkage groups . Evolutionary analysis revealed that, segmental duplication events which occurred around 67 MYA, were the primary force underlying Hsf genes expansion in sesame. Comparative analysis also suggested that sesame has retained most of its Hsf genes while its relatives viz. tomato and potato underwent extensive gene losses during evolution. Continuous purifying selection has played a key role in the maintenance of Hsf genes in sesame. Expression analysis of the Hsf genes in sesame revealed their putative involvement in multiple tissue-/developmental stages. Time-course expression profiling of Hsf genes in response to drought stress showed that 90% Hsfs are drought responsive. We infer that classes B-Hsfs might be the primary regulators of drought response in sesame by cooperating with some class A genes. This is the first insight into this gene family and the results provide some gene resources for future gene cloning and functional studies toward the improvement in stress tolerance of sesame. To cope with environmental stresses, plants have developed complex transcriptional systems that involve transcription factors Mittler, . AbioticHsfs constitute an important gene family involved in plant growth and development, as well as in responses to abiotic stresses  is, surprisingly, one of the most drought-tolerant species within the major crops of Asteridae subclass  among major oil crops    . The classification of candidate Hsf proteins into three different classes A, B, and C was performed by Heatster (http://www.cibiv.at/services/hsf/)  , web-based bioinformatics tool   of sesame genome on the basis of the information from Sinbase using the software MapChart 2.3     were searched against the DNA sequences of the Hsf genes using the web based software Websat (http://202.127.18.220/hg/). Reads per kilobase per million mapped reads (RPKM) values were log10 transformed and, finally, the heat map of hierarchical clustering was constructed using the MEV Software  and (hb168-drought sensitive) previously studied by Boureima et al.  were sowSIN_1006268)  to 889 amino acids (HSF21) and the isoelectric point ranging from 4.73 (HSF6) to 9.45 (HSF25). Table A total of 30 Hsf genes were confirmed in sesame genome with apparently complete Hsf-type DNA-binding domains and oligomerization domains ranging from 255 to 2646 bp in length  which were located on the unanchored scaffolds that could not be mapped to a specific LG, all the Hsf genes were unevenly distributed among 12 LGs out of the 16 LGs of sesame genome, suggesting that Hsf genes may have been widely distributed in the genome of the common ancestor  and one duplication event within the same LG6 (HSF14 and HSF15). The duplicated gene pairs are linked with black lines in Figure Analyzing of the duplication events can help to elucidate the evolution mechanisms of the sesame Hsf gene family. In total, 7 duplicated gene pairs across 11 LGs were identified including six segmental duplication events between different LGs , non-synonymous (Ka) and their ratio (Ka/Ks) values were used to examine the selective pressure and duplication time of the 7 sesame Hsf segmentally duplicated genes. In general, a Ka/Ks > 1 means positive selection, Ka/Ks < 1 indicates purifying selection, and Ka/Ks = 1 stands for neutral selection , 3 genes possessing 3 exons  and the intriguing gene HSF24 displaying up to 12 exons  with the subclass A1 more represented (4 members). The class B members were also classified into 4 subclasses namely B1, B2, B3, and B4, while all of the class C members were found to belong to the same subclass C1.To evaluate the evolutionary relationships of sesame Hsf genes, phylogenetic analysis was performed based on the full-length amino acid sequences of Hsf proteins from sesame, C Figure . Based oArabidopsis could provide more functional insight. Hence, we further performed a genome-wide comparative analysis to identify orthologous Hsf genes between sesame and Arabidopsis genomes. In total, 18 orthologous gene pairs were found across 9 LGs in sesame  conserved a tripled copy in Arabidopsis genome .Synteny analysis of sesame Hsf genes compared to those of e Figure . The LG3Arabidopsis, the protein–protein interactions, including functional and physical interactions among Hsf genes of sesame were predicated  interact directly with HSP genes, hence they might be some positive or negative regulators of HSP genes in responses to abiotic stresses and plant defenses. The 2 genes HSF19 and HSF9 seemed to be involved in the transcription regulation of other Hsf genes.The protein–protein interaction network is a helpful preface to explore the biological functions of unknown proteins. Based on the interactome of d Figure . ThirteeBased on the importance of Hsf genes in responses to various environmental stresses, tagging these useful genes could help in improving marker-aided breeding and establishing better crop-improvement strategies. Out of the 30 genes, only 7 SSR markers covering 4 LGs were identified , or tardily at the 6th day . For the second category of genes (2), they displayed the decrease of their expression levels under drought stress . Hence, in most cases, while the expression levels of the genes in category (1) decreased after re-watering period, the genes in category (2) increased their expression levels. Finally, the genes in category (3), showed minor fluctuations during drought stress and after re-watering .To understand the potential role of Hsf genes in sesame responses to drought, we monitored all sesame Hsf genes expression levels during progressive drought and after re-watering in two contrasted accessions (drought-tolerant and drought-sensitive). Since most Hsf genes displayed higher expression in root compared to the other tissues, qRT-PCR analysis was performed in sesame root samples. The results showed that some genes were highly expressed while others had low expression levels and revealed 3 types of expression patterns: (1) Up-regulated genes, (2) down regulated genes, and (3) no regulated genes Figure . In the Comparing expression patterns of Hsf genes in the drought-tolerant accession and the drought-sensitive one, results showed that most of time, the expression levels of Hsf genes were broadly higher in the drought tolerant accession. Overall, it appeared that regulation by drought is not specific to some Hsf classes but depends on the genes.Arabidopsis , potato (~840 Mb), tomato (~950 Mb) and the model plant Arabidopsis (~135 Mb), sesame (~370 Mb) bears more Hsf genes in its genome, suggesting that the number of Hsf genes is not necessarily linked to genome size but might be explained by the different evolutionary histories occurred within each species. Whole genome duplications have had a strong impact on species diversification and may have triggered evolutionary novelties  but higher than tomato (4 pairs). Six gene pairs are involved in segmental duplication while the pair of genes Arabidopsis helped in identifying some orthologous genes and allowed us to predict their functions in sesame. Indeed, gene orthology analysis can be used as a preliminary method to explore the function of candidate genes  reported to act as activator or repressor of heat inducible Hsf genes in Arabidopsis  in sesame revealed that they were significantly down regulated under progressive drought stress in the resistant accession as well as in the sensitive one. This suggests that these genes might also be involved in drought response pathways in sesame.Although HSF genes are well characterized in the heat stress-related pathway, they are poorly understood in other stress responses in Arabidopsis, similar pattern has been reported under heat stress with AtHsfA1a and AtHsfA1b involved in the early response to heat stress (Lohmann et al., To cope with prolonged drought stress, sesame uses different set of Hsf genes belonging to class B4, class B3 and class A1 to maintain housekeeping gene expression. In Arabidopsis and U. gibba helped to classify these genes into 3 major classes with members of class A the most abundant. These genes were unevenly distributed in 12 of the 16 LGs. Segmental duplication events contributed to the expansion of Hsf genes and have played key roles in their functional divergence. All sesame Hsf genes were found expressed differentially in all tissues and organs examined according to the RNAseq data analysis.The importance of Hsf gene family has attracted many investigations on different crops. This study presents a comprehensive overview of this gene family in sesame. Here, we reported 30 non-redundant full length Hsf genes in the sesame genome. Structural characteristics and the comparison with Sesame is the model plant for oil crops with small genome size and high oil content in its seed. Drought is one of the major constraints which impair its production. Therefore, understanding the role of stress related genes such as Hsf in sesame is of a significant meaning.Expression analysis of Hsf under drought stress showed differences in their expression patterns, confirming this gene family as potential candidate for improvement of drought tolerance in sesame. The class B-Hsfs were the most expressed ones under drought stress and we propose these genes for future gene cloning and functional analyses toward the improvement of drought and other abiotic stresses tolerance in sesame cultivars.KD carried out the bioinformatics, experiments, data analysis and drafted the manuscript. DD participated in data analysis and revised the manuscript. NC supervised the experiments and revised the manuscript. All authors have read and approved the final manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Increased hydrostatic pressure as seen in cardiogenic edema or increased vascular permeability as present in inflammatory lung diseases such as the acute respiratory distress syndrome (ARDS) causes a reversal of transepithelial fluid transport resulting in the formation of pulmonary edema. The basolateral expressed Na+-K+-2Cl− cotransporter 1 (NKCC1) and the apical Cl− channel cystic fibrosis transmembrane conductance regulator (CFTR) are considered to be critically involved in the pathogenesis of pulmonary edema and have also been implicated in the inflammatory response in ARDS. Expression and function of both NKCC1 and CFTR can be modulated by released cytokines; however, the relevance of this modulation in the context of ARDS and pulmonary edema is so far unclear. Here, we review the existing literature on the regulation of NKCC1 and CFTR by cytokines, and—based on the known involvement of NKCC1 and CFTR in lung edema and inflammation—speculate on the role of cytokine-dependent NKCC1/CFTR regulation for the pathogenesis and potential treatment of pulmonary inflammation and edema formation.Pulmonary edema, a major complication of lung injury and inflammation, is defined as accumulation of extravascular fluid in the lungs leading to impaired diffusion of respiratory gases. Lung fluid balance across the alveolar epithelial barrier protects the distal airspace from excess fluid accumulation and is mainly regulated by active sodium transport and Cl Pulmonary edema, defined as excessive fluid accumulation in the interstitial and air spaces of the lungs, is a life-threatening condition leading to impaired gas exchange and respiratory failure. Depending on the underlying cause, pulmonary edema is distinguished into two types; hydrostatic and permeability-type edema. The most common form of hydrostatic edema is cardiogenic edema which occurs as major complication of left-sided heart failure and is characterized by increased transcapillary hydrostatic pressure gradients between pulmonary vasculature and interstitial space resulting in interstitial lung edema and flooding of the alveoli with protein-poor fluid. Permeability-type lung edema, also referred to as non-cardiogenic pulmonary edema, is defined by an exudation of protein-rich fluid into the alveoli and develops characteristically in the process of inflammatory lung diseases such as the acute respiratory distress syndrome (ARDS) , 2. Two + transport via epithelial Na+ channel (ENaC) and the Na+/K+-ATPase. In this review, we propose that cytokine-dependent regulation of Na+-K+-2Cl− cotransporter 1 (NKCC1) and Cl− channel cystic fibrosis transmembrane conductance regulator (CFTR) may play a critical role in lung edema formation and pulmonary inflammation. To this end, we first outline the general principles of alveolar fluid transport and the role of inflammatory cytokines in lung edema formation, then focus specifically on the role of NKCC1 and CFTR in pulmonary edema and inflammation, and their regulation by cytokines, and finally conclude by proposing a critical role for cytokine-dependent regulation of NKCC1 and CFTR as a novel concept in the pathogenesis of pulmonary edema.Several transporters    and chloporin 5) . Althougransport , 18.− secretion  or absence (in vitro assays) of immune cells. Detailed dissection of these scenarios poses a considerable challenge in terms of both resources and appropriate assays, yet would provide an invaluable platform for a better understanding of the complex crosstalk between inflammation and ion channel activity in a wide range of pulmonary and systemic inflammatory diseases.Overall, there is evidence that cytokines are important regulators of active ion transport and AFC. However, exact regulation of ion channels by inflammatory cytokines may be a complex phenomenon with functional effects depending on temporal and spatial profiles, interdependence between various cytokines, and the presence  mediates active electroneutral uptake of one Naithelium . Both isithelium .+ level, increase in intracellular cAMP, or changes in cell shape, and depends on direct phosphorylation by Ste20-related proline/alanine-rich kinase (SPAK) and oxidative stress responsive kinases (OSR1)  .− anion depending on the electrochemical gradient. CFTR is expressed on apical membranes of epithelial cells in distal airways and alveolar epithelium, where it mediates Cl− transport to maintain alveolar fluid homeostasis  in the lung and kidney . WhetherKlebsiella pneumoniae infection. Mice lacking NKCC1 were protected from bacteremia and lethal sepsis after infection and showed decreased vascular permeability. The number of migrated neutrophils in the air space was increased leading to a reduced number of K. pneumoniae in the lung of NKCC1-deficient mice. A potential mechanism that may explain the involvement of NKCC1 in edema formation and neutrophil transmigration was proposed by Matthay and Su  pathway (For CFTR, the interplay between inflammatory cytokines and channel expression/activity is even more complex. As such, IL-8 has been shown to indirectly regulate activity and biosynthesis of CFTR through inhibition of the β pathway  and subs pathway . Downreg pathway . Likewis pathway . In 2007Other studies, reported an upregulation of CFTR mRNA and protein by IL-1β –72. The Contradictions in CFTR regulatory processes and its involvement in fluid transport and edema formation may result from differences in expressed transport system in various cell types, and such heterogeneity may also be present in the pulmonary epithelium. Recently, it has been proposed that the distal airways might be comprised of secreting areas, located in the contra-luminal regions of the pleats, and absorbing areas in the folds . SecretiAcute respiratory distress syndrome with edema formation is a serious complication in critically ill patients. Resolution of edema needs strategies to restore epithelial barrier function and improve AFC. Formation of pulmonary edema in inflammatory lung diseases is caused by the loss of endothelial and epithelial barrier and impaired fluid and ion transport across the alveolar epithelium. Pro-inflammatory cytokines like TNF-α, TGF-β1, and IL-1β, which are released and activated in the early phase of lung inflammation, may regulate expression and activity of ion channels involved in fluid transport including NKCC1 and CFTR. Regulation of NKCC1 and CFTR is, however, complex, with discrepant results potentially depending on time profile, cell type, and co-stimulation by different cytokines resulting in a distinct multi-dimensional response that favors AFS while impairing AFC. Manipulation of expression and activity of NKCC1 and CFTR might serve as therapeutic target in inflammatory lung diseases with edema formation.Both authors, SW and WK, meet the following four criteria of authorship: 1. Substantial contributions to the conception or design of the work. 2. Drafting the work and revising it critically for important intellectual content. 3. Final approval of the version to be published; 4. Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Metabolite transport between organelles, cells and source and sink tissues not only enables pathway co-ordination but it also facilitates whole plant communication, particularly in the transmission of information concerning resource availability. Carbon assimilation is co-ordinated with nitrogen assimilation to ensure that the building blocks of biomass production, amino acids and carbon skeletons, are available at the required amounts and stoichiometry, with associated transport processes making certain that these essential resources are transported from their sites of synthesis to those of utilisation. Of the many possible posttranslational mechanisms that might participate in efficient co-ordination of metabolism and transport only reversible thiol-disulphide exchange mechanisms have been described in detail. Sucrose and trehalose metabolism are intertwined in the signalling hub that ensures appropriate resource allocation to drive growth and development under optimal and stress conditions, with trehalose-6-phosphate acting as an important signal for sucrose availability. The formidable suite of plant metabolite transporters provides enormous flexibility and adaptability in inter-pathway coordination and source-sink interactions. Focussing on the carbon metabolism network, we highlight the functions of different transporter families, and the important of thioredoxins in the metabolic dialogue between source and sink tissues. In addition, we address how these systems can be tailored for crop improvement. Metabolite transport not only allows the flawless coordination of pathways in different organelles and between cells, but it is also balances energy provision and utilisation throughout the whole plant. Plant metabolite transport displays enormous plasticity and flexible regulation. Focussing particularly on carbon transporters, this review discusses transport functions in source and sinks organs, with sucrose and trehalose in source-sink communication that encompasses sophisticated perception and signalling systems. •Metabolite transport facilitates inter-pathway regulation, cell to cell communication and co-ordination of source and sink processes.•Highlighting the carbon metabolism network, this review focuses on the role of transporters, carbon flow, and signalling.- The integration of sucrose and trehalose pathways as nodes in the regulation of plant growth and signalling is approached. Plant cells synthesize all of the metabolic building blocks for growth, biomass production and defence such as sugars and carbohydrate polymers, lipids, amino acids and secondary metabolites such as alkaloids and terpenoids. Metabolite fluxes through parallel pathways often occur simultaneously in differing cellular compartments 22 Enrichment) systems have demonstrated that nitrogen use efficiency will increase as atmospheric carbon dioxide becomes more available 3− and NH4+ transporters The efficient operation of carbon metabolism leading to carbon gain intrinsically depends on the successful uptake of other nutrients particularly nitrogen and phosphorus. Increasing focus is being placed on this interdependence because of the uncertainties that persist regarding how plant yields will be influenced by climate change and the increasing availability of carbon dioxide in the atmosphere. On one hand, studies in FACE . While the activity of this enzyme is regulated in response to environmental and metabolic triggers as well as protein phosphorylation, the rate of nitrate assimilation can be limited by the availability of NADH 4+), which is assimilated into amino acids by the glutamine synthetase/glutamine-2-oxoglutarate aminotransferase (GS-GOGAT) pathway. Thereafter, a raft of aminotransferases and other enzymes catalyse transfer of the amino group to form other amino acids. Provision of the 2-oxoglutarate required for ammonia assimilation requires partial operation of the TCA cycle in the mitochondria Nitrite generated by the action of NR is transported into the chloroplasts where it is reduced by nitrite reductase (NiR) to ammonium (NH32 fixation pathway enzymes requires thioredoxins (TRX), which are small proteins with disulphide reductase activities The extensive cycling of reducing equivalents facilitated by metabolite transport 2 fixation are matched to rate of production of reduced ferredoxin and NADPH The photosynthetic electron transport chain provides the reductive “push” that keeps the stromal TRXs reduced in the light, ensuring that the activation states of the thiol modulated enzymes involved in COArabidopsisAppropriate resource allocation between different plant organs might also be achieved by post-translational modification of sucrose transporters. Sucrose export from leaves occurs both in the light and dark to ensure the continuous and stable provision of adequate carbon resources to drive plant growth and development. The transport of sucrose is mediated by membrane-localised sucrose transporters, whose properties will be discussed later in detail. The activities of these transporters are regulated by changes in cellular redox status and by protein-protein interactions 4Triose phosphate/phosphate, glucose, maltose transporters are important mediators of carbon transfer between the plastids and cytosol 2 into sucrose and had higher leaf starch/sucrose ratios than the wildtype Arabidopsis lines over-expressing TPT and also fructose-1, 6-bisphosphatase had higher photosynthetic carbon assimilation rates. In addition, these lines also accumulated more sucrose, glucose and fructose than controls and showed enhanced growth compared to the wild type TPT is relatively abundant in the chloroplast inner membrane, constituting 10–12% of the protein content enolpyruvate (PEP) and 2-phosphoglyceratefor phosphate across the inner plastid envelope membrane in heterotrophic tissues Arabidopsis, AtPPT2 is expressed in leaves and AtPPT1 transcripts are localised only in the vasculature. Analysis of Atppt1 mutants demonstrated that this transporter is essential for plant development and metabolism AtPPT1 may be involved in signal transduction through its association with phenylpropanoid metabolism cue1 mutant, which is defective in PPT and shows altered chloroplast development, has dark-green veins and light-green interveinal regions cue1 mutant phenotype could not be rescued by the over-expression of a cauliflower PPT cue1 mutants suggested that leaf and root PPTs may fulfil different roles, with the leaf chloroplast PPT acting as a PEP importer while the root plastid PPT acts as an overflow valve Another type of phosphate transporter (PPT) facilitates the transport of three-carbon compounds containing a phosphate group at the C2 position, such as phosphoArabidopsis genome contains two GPT genes, AtGPT1 and AtGPT2GPT1 is expressed in a similar manner to genes involved in starch metabolism Arabidopsis Atgpt1 mutants have severe defects in pollen development GPT2 led to an inhibition of carbon metabolism While PPTs are present in both photosynthetic and heterotrophic tissues, another group of phosphate transporters, the glucose-6-phosphate/phosphate transporters (GPT), are found only in heterotrophic tissues The xyulose-5-phosphate transporters (XPT) catalyse the exchange of xyulose-5-phosphate and to a lesser extent ribulose-5-phosphate for Pi 5Just as triose phosphates are the main end-products of photosynthesis that are exported by chloroplasts, sucrose is the major export carbohydrate of leaves In addition to carbohydrate storage in leaves as starch, sucrose, hexoses and raffinose can also be stored in the vacuoles Arabidopsis (AtSUT4) are able to transport sucrose when expressed in yeast Although the sucrose stored in leaf vacuoles represents only are small amount of the sucrose transported to the phloem, vacuolar sucrose levels can exert a strong effect on photosynthesis and stress tolerance. Moreover, vacuolar sucrose storage is particularly important in supporting the heterotrophic growth of reproductive tissues and developing embryos. The transport of sucrose within leaf mesophyll cells is driven by the concentration gradient between in the cytosol and vacuole Arabidopsis tonoplast monosaccharide transporter (TMT) family consists of three members, which are expressed in a tissue- and cell-specific manner. TMT1 is expressed in pollen, flowers and young developing tissues and TMT2 is expressed in young roots, floral tissues and mature leaves. In contrast, TMT3 transcripts are low in abundance, and are found only in seedlings, mature leaves and stamens. The expression of TMT1 and TMT2 is increased in response to drought and cold treatments, suggesting a role for these transporters in the response to environmental stresses BvTST2.1 was found to contribute to vacuolar sucrose uptake. This transporter operates as a proton antiporter, and has a high similarity to Arabidopsis TMT family amino acid sequences. This prompted the name change of the TMT family of transporters, to the TST family (tonoplast sucrose transporters) AtVGT1) is localised on the tonoplast membrane in Arabidopsis. The Atvgt1 mutants showed delayed flowering, together with a reduced capacity for viable seed production The 6The distribution of resources between plant organs relies on the plant vasculature system comprising of xylem and phloem. The xylem is responsible for the transport of water and minerals collected from roots up to the shoots. The phloem is responsible for the transport of nitrogen- and carbon-containing compounds from source tissues such as leaves, to sink tissues. The phloem tissue consists of two cell types, sieve element (SE), responsible for nutrient conduction, and companion cell (CC), which provides metabolic support for the SE The phloem is an important trafficking path in source/sink interactions linking key processes required for sugar signalling that not only controls the flow of sugars to developing organs, but also influences gene expression and hormone signalling throughout the plant SUCs or SUTs) in Arabidopsis. Most SUTS are sucrose/H + symporters. However, other sucrose transporters are classified as sucrose facilitators (SUFs) because they catalyse a pH-independent and energy-dependent bi-directional transport of sucrose Sucrose transporters play an integral role in apoplastic phloem loading and unloading, as well as in the exchange of sucrose between the plant and beneficial and/or parasitic symbiotic organisms sut1 had stunted growth, delayed flowering, and early senescence linked to a lower capacity for sucrose export SUT1 function results in reduced sucrose transport while increased SUT1 expression results in increased sucrose transport SUT1 in apoplastic loading in autotrophic/source tissues, and unloading in heterotrophic/sink tissues. While SUT1 is a key transporter in phloem loading and unloading, the other SUT proteins are important in cell-type specific sucrose transport particularly during reproductive development. For example, members of the SUT2 family are expressed in the phloem SEs and also in pollen. Loss of SUT2 function in tomato decreased pollen viability, through reduced sucrose uptake SUT4 is expressed during seed germination, as well as in pollen and in anthers at the post heading stage. Arabidopsis SUT5, which is expressed specifically in the endosperm, is considered to be a nutrient carrier of the filial tissues during early seed development In apoplastic loading/unloading species, sucrose is transported from the apoplast to the SE/CC by the SUT1/SUT3 (dicot/monocot) H +/sucrose co-transporter Arabidopsis that fall into four clades. In rice, there are 21 SWEET family members falling into the same four clades. The function of clade II and clade IV members remains to be identified, however members of clade I have been shown to mediate glucose import/export While the SUT super-family are major transporters involved in the translocation of sucrose between the apoplast and phloem, other transporters responsible for the movement of sucrose also fulfil important roles. For example, the SWEET transporters have been implicated in the transport of sucrose from the phloem parenchyma to the apoplast Arabidopsis (AtSWEET11) was localised to the plasma membrane Atsweet11 and Atsweet12 mutants had no marked phenotype. However, Atsweet11:12 double mutants had slower growth and showed carbohydrate accumulation in the leaves Atsweet11:12 mutants were not as severe the sut1 mutants, indicating that other SWEET proteins may compensate for the loss of SWEET11 and SWEET12 activity The SWEET transporters are localised in the phloem parenchyma. GFP-tagged SWEET11 from 7Arabidopsis starch excess (sex) mutant was originally thought to have reduced expression of a chloroplast hexose transporter mex) mutants, which are defective in the maltose transporter MEX1, were unable to convert starch into sucrose during the night, leading to increased starch accumulation in leaves mex1 mutants were unable to degrade starch during the night MEX1 is expressed in mature apple leaves and also in sink tissues. The function of the MEX1 transporter in sink tissues is unknown but it is likely to be required to support seedling growth, ensuring rapid use of stored carbohydrates to drive growth Excess carbohydrates are often stored as starch in source and sink tissues. Sucrose transported from leaves is used for the synthesis of starch at sites where carbohydrate storage is required, for example in seeds Tie-Dyed1 (Tdy1), which has only been described in grasses, is a transmembrane protein that promotes sucrose loading into the phloem tdy1 mutants are stunted with chlorotic leaves because of excessive leaf starch accumulation Tdy1 functions in carbon partitioning through the promotion of phloem loading sucrose export defective 1 (sxd1) mutant displays a similar phenotype to tdy1In addition to transporters, other proteins have been implicated in starch accumulation. HvSUT1 was directly associated with sucrose accumulation in the caryopses, where sucrose influx correlated with increased starch accumulation ArabidopsisArabidopsissweet11;12;15 triple mutants showed severe defects in seed development producing lower weight wrinkled seeds, with reduced starch and lipid There may be differences in the types of sugar transporters used to support grain development in different species. For example, HvSUT1 has been implicated in seed starch accumulation. The expression of 8Processes that consume sucrose are sensitive to stress-induced inhibition. For example, sucrose accumulation is observed in plants exposed to low temperatures TPS1. Arabidopsis mutants lacking the trehalose phosphate synthase gene, tps1 are embryo lethal − 1 FW in Arabidopsis seedlings T6P is a universal signal of sucrose concentration in plants ArabidopsisLarge differences in synonymous and non-synonymous TPS and TPP substitutions have been observed in 9Manipulations of T6P levels have provided a new paradigm for crop improvement Recent studies have confirmed the central role of T6P in managing whole plant carbon budgets and stress responses SnRK1 may not be the only target of T6P. In mature leaves T6P does not inhibit SnRK1 because of different composition of SnRK1 complexes between heterotrophic and autotrophic tissues 10Plant metabolite transporters are crucial to inter-pathway regulation, cell to cell communication, and source-sink interactions. The sophisticated vasculature of plants is rich in transporters, which regulate the partitioning of resources and signals between source and sink organs. Carbon metabolism and transport is at the heart of whole plant communication and underpins key agricultural traits such as flowering, productivity and stress tolerance An important consideration when aiming to improve crop yields is whether the yield itself is source or sink limited, which appears to be species-dependent. In potatoes for example, source capacity limits yield by up to 80% under glasshouse conditions There is no conflict of interest.Transparency document.


Since mast cells terminate their differentiation in their tissue of residence in response to specific microenvironmental cues, each tissue may comprise unique mast cell subtypes, and responses are tailored to the danger signals that are likely to be encountered in each anatomical location. From a transcriptional point of view, these cells therefore must be endowed with epigenetic and transcriptional programs that allow them to maintain a stable identity and at the same time allow sufficient plasticity to adapt to different environmental challenges. In this commentary, we highlight some of the recent findings that advanced our understanding of the transcriptional and epigenetic programs regulating mast cell functions.Mast cells are tissue-resident, innate immune cells present in most tissues of the body and are important effector and immunomodulatory cells. Differentiated mast cells typically are characterized by the surface expression of the receptors KIT and FcεRI, the latter especially being important for stimulation through IgE antibodies, although these cells have the ability to respond to a wide variety of environmental signals, to which they can variably react by releasing pre-stored or Indeed, these cells are most notably located in vascularized tissues, including the skin, the mucosa of the lungs, and the gastrointestinal tract, where they reside primarily at the interface with the environment, namely beneath the epithelial surface. The clearest examples of immune-related responses in which mast cells play a key role are in the context of allergy6 as well as in immunity against parasites7. However, these cells have been involved in a plethora of processes, either protective of  or damaging to (chronic inflammation and cancer and autoimmune diseases9) the organism, and some of the proposed functions of these cells have also become a matter of debate10. The main reasons for the difficulties in obtaining concluding evidence about mast cell functionsin vivo include the complications linked to studying tissue-resident cells as well as the complexity of mast cell phenotypes and responses. Indeed, mast cells carry a wide repertoire of receptors and can be activated by an impressive number of different stimuli11  and stem cell factor15 as compared with freshly isolated mast cells from human skin16. Transcriptional changes reflected primarily metabolic activation, most likely linked to culture-induced cell cycle progression; however, other transcriptional changes (such as the induction of genes characteristic of other lineages) were suggestive of problems in fully maintaining cell identityin vitro. To add to this complexity, circulating human mast cell progenitors are very rare and difficult to differentiatein vitro, and so far noin vitro system has been able to recapitulate the wide variety of phenotypes or states that are likely to existin vivo. Indeed, the complexity of signals and microenvironmental cues that lead to the migration of mast cell progenitors to specific tissues remains to be fully unraveled, although these cells are clearly influenced by changes in their cytokine milieu and by the presence of activating factors12.Mast cells are one of the innate immune cell types involved in the first line of defense from pathogens that attempt to breach the epithelial barriers of our organismmuli11 , which c17 (18. Mast cell–derived IL-33 in turn activated group 2 innate lymphoid cells (ILC2) to produce IL-13, leading to goblet cell hyperplasia and worm expulsion. Similarly, mast cells have an established role in allergic reactions, and their contribution to such responses is dependent on the acquisition of antigen-specific IgE antibodies that are bound to the high-affinity IgE receptor (FcεRI) on the cell surface. However, it was only recently elucidated that for mast cells to acquire IgE antibodies from the blood, they must display a preferential perivascular location, which enabled direct access to the blood and sampling of the intravascular lumen through cellular projections19. Also, mast cells turned out to have a crucial role in orchestrating the exfoliation of epithelial cells in the bacterially infected bladder, thereby inducing an important defense mechanism aimed at reducing bacterial burden20. Indeed, IL-1β produced by bacterially exposed bladder epithelial cells potently recruited mast cells to the site of infection; uptake of the released mast cell granules by epithelial cells was followed by the release of the mast cell protease Mcpt4 and caspase-1 activation, eventually leading to cell death20. Although the specific signals that induced mast cell degranulation in the infected bladder remain to be elucidated, this study highlighted how mast cells can influence the outcome of many different physiological responses. Mast cells were also shown to suppress humoral and cell-mediated responses in the bladder, through the production of the anti-inflammatory cytokine IL-10, most likely in an attempt to protect the organ from excessive tissue damage21. Whether the same cell can switch from a pro- to an anti-inflammatory phenotype during the course of an infection in the bladder, or instead different subsets are involved, remains to be determined. Interestingly, mast cell–derived IL-10 was also shown to modulate contact hypersensitivity reactions, although the extent of IL-10 production  appeared to be variable depending on the severity of the model of contact hypersensitivity used6.Besides the challenges of studying mast cells, why should we care about these cells and how they are regulated? Studying mast cells has the obvious implication of a better understanding of mechanisms that are involved in allergy and asthma as well as in mast cell–proliferative diseases17 , and as ex-vivo–derived tissue cells attempted16. Since mast cells differentiate in local tissue niches, it is probable that they adaptively develop characteristic features that allow them to best function within a given context22. Indeed, the fact that tissue mast cells can be quite heterogeneous  has been recognized for quite some time24. However, from a transcriptional point of view, studying the heterogeneity of tissue mast cells implies the ability to extract them directly from various tissues and perform transcriptome analyses such as RNA sequencing. In this kind of analysis, mast cell heterogeneity may be reflected in differences in their gene expression programs and this is exactly what has been observed in murine mast cells extracted from different tissues25. Indeed, mouse mast cells derived from various anatomical locations  displayed a high degree of heterogeneity across the different tissues, although they clustered distinctly from other profiled lymphoid and myeloid cell types, including basophils and other granulocytes. Some signature genes that specifically characterized mast cells included a number of proteases such asCtsg, encoding for cathepsin G; the metalloprotease geneAdamts9; andC2, encoding for the complement component C2 of the classic C3 convertase25. Among the transcription factors,Crebl1,Smarca1, andZfp9 appeared to be relatively specific for mast cells, although their role remains unknown, whileMitf, a transcription factor crucial for mast cell differentiation and functions34, clearly defined mast cells from other cell types. Highlighting once again the complications associated with studies of tissue-resident cells, the authors found that incubating peritoneal mast cells in the presence of the digestion enzymes required for tissue extraction was already sufficient to alter the expression of more than 100 genes, including the gene encoding for the transcription factor Egr2. They therefore proceeded to compare enzymatically treated peritoneal mast cells with other mast cell populations enzymatically extracted from the tissues. Such analysis revealed that, overall, mast cells from the different tissues shared a core signature of 128 genes, including genes encoding for proteases or involved in metabolic pathways important for the generation of the wide repertoire of mediators that characterize mast cells. Comparative analysis of cells from the different tissues showed that mast cells from the trachea, esophagus, and tongue displayed the highest transcriptional similarity, although some specificity remained. For example, the gene encoding for the proteaseMcpt1 appeared to be relatively specific for mast cells from the esophagus. Peritoneal and skin mast cells appeared to be more divergent in their transcriptional profiles, with differential expression of a number of genes, including the adhesion molecule CD34 (which was absent in skin mast cells), the transcription factor SOX7 (increased in skin mast cells), and the integrin β2, the last of which instead was preferentially detected in peritoneal mast cells. Interestingly, peritoneal mast cells were characterized by a transcriptional signature significantly associated with mitosis, and indeed these cells appeared to undergo proliferation even in the absence of inflammation25.Many studies have assessed the transcriptional profile of mast cells, from both human and mouse, although for the most part they used cultured cells, and only in rare cases was a comparison with35, and STAT5 activity in mast cells was linked to allergen-induced dermatitis36. Interestingly, several transcription factors also showed some level of crosstalk in regulating mast cell differentiation and functions: for example, C/EBPα and MITF acted antagonistically in the specification of the basophil and mast cell lineages37, while STAT5 acted upstream of GATA2 in the differentiation pathways leading to either mast cells or basophils38. Other transcription factors such as HES139, EGR family members41, or ZEB242 have also been associated with at least some specific aspects of mast cell biology23, although their exact rolein vivo or their detailed mechanism of action at the genomic level requires further investigation. Of note, many of the transcription factors that are involved in mast cell activation  are also more general regulators of inflammatory genes in many immune cell types, and they will not be extensively discussed here. We refer the reader to a more comprehensive review on this topic23.Apart from MITF, other transcription factors that are known to positively or negatively impact mast cell differentiation or function (or both) belong to the GATA, STAT, and C/EBP families  stimulation of mast cells can induce a state of unresponsiveness to a subsequent stimulation which is similar to the endotoxin tolerance described for macrophages, thereby probably representing a genuine example of mast cell short-term memory46, and some crosstalk between IgE and LPS stimulation in mast cells was also reported47. However, mast cells can be directly activated by many additional stimuli  enzymes revealed the unmistakable importance of this epigenetic modification during development50; however, the molecular mechanisms underlying the embryonic or perinatal lethality observed in the absence of DNMT enzymes remain far from being firmly established. Indeed, distinguishing causality from association or direct and indirect effects of chromatin-related processes remain major challenges48.Chromatin modifications such as covalent modifications of histone tails or DNA methylation are epigenetic mechanisms of regulation of transcription, which include all of those mechanisms that influence gene expression by modulating the accessibility of regulatory regions to transcription factors without altering the DNA sequence. Epigenetic modifications are critical mechanisms that modulate the interplay of genomic sequences with environmental signals, and indeed they have a crucial role during development, in the maintenance of cell identity, in cell differentiation, and in regulating acute responses to stimuli. Because of the complex networks in which these mechanisms act, and their ability to affect the entire genome, epigenetic studies often suffer from major obstacles that hinder our mechanistic understanding of the biological role of epigenetic modifications51, pointing toward a key role for histone modifications in this process. Interestingly, mast cells appear to exploit an atypical epigenetic regulatory mechanism, mediated by the endogenously produced protease tryptase that not only can be secreted by the cells to affect the extracellular milieu but also can translocate into the nucleus of the producing cell, where it mediates the cleavage of histone tails, thereby modulating gene expression52. While some mechanistic aspects (such as the regulation of tryptase nuclear translocation) remain to be understood, this example further highlights the potential importance of histone modifications in mast cell biology. Accordingly, histone deacetylase inhibitors appeared to impact the proliferation and viability of pathogenic mast cells derived from patients with mast cell–proliferative disorders53. But in general, very few studies have investigated the role of histone modifications or histone-modifying enzymes in regulating mast cell differentiation and function. Further studies in this direction, especially in primary mast cells obtained from tissues, would certainly provide further insights about how these cells are regulated and what goes wrong during disease.What is the role of epigenetic modifications in regulating mast cell biology? In terms of histone modifications, by assessing the role of the regulatory subunit ASXL1 of a deubiquitinase complex in hematopoietic differentiation, a recent study showed that altered levels of monoubiquitination of lysine 119 on histone H2A affected mast cell differentiation54. The importance of this process in transcriptional regulation is highlighted not only by the altered developmental processes observed in the absence of DNMT enzymes but also by the many examples of disease, including hematological malignancies, in which DNMT enzymes are mutated and DNA methylation is affected55. Methylated cytosines in the genomic DNA can also be oxidized to 5-hydroxymethylcytosine (5hmC) by the action of the ten-eleven-translocation enzymes TET1-3 . Such modification can influence gene expression either by interfering with the binding of transcription factors and co-regulators to a given DNA sequence or by recruiting specific methyl-binding proteins TET1-3 . Such mo62. In particular, mastocytosis is characterized by the abnormal proliferation and accumulation of mast cells in various organs and tissues. While the exact cause of mastocytosis remains unclear, it is frequently associated with mutations in theKIT oncogene, most commonly an aspartic acid–to–valine substitution at codon 816, causing spontaneous activation of the KIT receptor62. One of the first indications that DNA methylation–related processes might be important in mast cell biology came from the observation that decitabine, a demethylating agent used in the clinic for the treatment of myeloproliferative and myelodysplastic disorders, induced apoptosis of neoplastic mast cells, at leastin vitro63. Moreover, mutations in the gene encoding forDNMT3A were identified in 3 out of 26 patients with systemic mastocytosis64, whileTET2 mutations were identified in at least 20% of the patients65, and these correlated with worse overall survival64. Accordingly, reduced levels of cytosine modifications were observed in patients with systemic mastocytosis66, and altered DNA methylation patterns were reported in tissues and cells of patients with asthma67. However, patient studies are by necessity mostly correlative, and becoming able to distinguish whether such changes are cause or consequence or simply associate with a certain phenotype can be a daunting task. For example, systemic mastocytosis patients carryingTET2 mutations tended to be older and have higher monocyte counts64; since inactivatingTET2 mutations also accumulate with age in healthy individuals69, the boundaries between cause and consequence remain problematic to define. Indeed, a recent mutational analysis of more than 2,500 human subjects identified mutations inTET2 andDNMT3A as the most common age-associated mutations even in healthy individuals, andTET2 mutations had a stronger impact on the steady increase in hematopoietic clonal expansion compared withDNMT3A mutations69. While the effects of these mutations in disease and in the normal processes of aging are being uncovered, in the future further studies will certainly lead to a better understanding of the exact role of DNA-modifying enzymes and epigenetic mechanisms in regulating mast cell functions in the context of immune responses and in disease.Mast cell–related diseases manifest in a wide range of disorders displaying activation or proliferative dysregulation or both 31,62. in vivo visualization of mast cells and their in-depth molecular analysis, we are learning more about the role of these cells in various models of disease and inflammatory responses, and we are also better able to dissect some of the mechanistic aspects of such responses. However, despite the great advancements in the field in recent years, many of the mechanisms and factors underlying mast cell differentiation and responses remain poorly defined. In the future, the combination of traditionalin vitro and single-molecule studies with single-cell genomic and genome-wide approaches70 will certainly improve our understanding of mast cell subsets and functions, potentially allowing us to analyze them within the physiological context of their microenvironment. Such developing tools will surely provide definite answers to many of the questions about mast cell biology in health and disease which we are just starting to address.Thanks to the development of novel mouse models and to technological advancements allowing the


Immunohistochemistry detected high levels of activated prostasin in the granular layer, but only low levels of activated matriptase restricted to the basal layer. Immunoblot analysis of foreskin lysates confirmed this in vivo zymogen activation status and further revealed that HAI-1 but not HAI-2 is the prominent inhibitor for prostasin and matriptase in skin. The zymogen activation status and location of the proteases does not support a close functional relation between matriptase and prostasin in the human skin. The limited role for HAI-2 in the inhibition of matriptase and prostasin is the result of its primarily intracellular localization in basal and spinous layer keratinocytes, which probably prevents the Kunitz inhibitor from interacting with active prostasin or matriptase. In contrast, the cell surface expression of HAI-1 in all viable epidermal layers renders it an effective regulator for matriptase and prostasin. Collectively, our study suggests the importance of tissue distribution and subcellular localization in the functional relationship between proteases and protease inhibitors.The membrane-bound serine proteases prostasin and matriptase and the Kunitz-type protease inhibitors HAI-1 and HAI-2 are all expressed in human skin and may form a tightly regulated proteolysis network, contributing to skin pathophysiology. Evidence from other systems, however, suggests that the relationship between matriptase and prostasin and between the proteases and the inhibitors can be context-dependent. In this study the  Matriptase is a type 2 transmembrane serine protease –3 and prIn spite of this well-defined functional relationship, the inverse matriptase and prostasin expression pattern that can be observed through the course of epidermal differentiation  suggestsMost serine proteases are synthesized as zymogens with limited intrinsic activity. Zymogen activation, which generates the active protease, represents one of the most important mechanisms by which the function and enzymatic activity of proteases can be temporally and spatially regulated. Zymogen activation status can, therefore, also be an important criterion in determining the functional linkage between two serine proteases which are postulated to function as a tightly coupled cascade or which form protein complexes for their mutual zymogen activation . This isAlexa Fluor 594 goat anti-mouse IgG and Alexa Fluor 488 phalloidin were obtained from Molecular Probes . 5,5’-Dithio-bis-(2-Nitrobenzoic Acid) (DTNB) and 4',6-diamidino-2-phenylindole (DAPI) were obtained from Sigma-Aldrich ; Horseradish peroxidase (HRP)-conjugated secondary antibodies were purchased from Kirkegaard & Perry Laboratories , Western Lightning Chemiluminescence Reagent Plus was purchased from PerkinElmer Life Sciences .2.HaCaT human keratinocytes , were maintained in DMEM supplemented with 10% fetal bovine serum (FBS). The immortalized human mammary epithelial cells 184 A1N4   were culThe monoclonal antibody (mAb) M24 for total matriptase, the mAb M69 for activated matriptase, and the mAb M19 for HAI-1 were generated using purified matriptase-HAI-1 complex as the immunogen and characterized previously , 26. TheThe skin tissue sections were obtained from patients, with written informed consent by the Tri-Service General Hospital (TSGH), National Defense Medical Center under IRB protocol 099-05-019, approved by the TSGH Institutional Review Board (IRB). Immunohistochemical staining was conducted as described in previous studies , 19, 29.Human mammary epithelial cells 184 A1N4 and HaCaT human keratinocytes cultured in 60 mm culture dishes were washed with PBS three times and then incubated with 150 mM phosphate buffer pH 6.0 at room temperature for 20 min as previously describe , 32. Theg for 20 min and lysed in RIPA buffer supplemented with the Roche Complete Protease Inhibitor Cocktail . Residual human immunoglobulins in the samples were depleted by incubating the foreskin lysates with Pierce protein A/G agarose (ThermoFisher Scientific).Our previous study has shown that the tissue distribution of matriptase in human foreskin is the same as in the adult skin . In ordeEqual amounts of proteins from the cell lysates or tissue lysates were diluted in 5x SDS sample buffer containing no reducing agent and incubated at room temperature for 5 min prior to loading onto the gels. Proteins were resolved by 7.5% SDS-PAGE, transferred to nitrocellulose membranes, and probed with the indicated mAbs. The binding of mAbs was detected using HRP conjugated secondary antibodies, and visualized using Western Lightening Chemiluminescence Reagent Plus (Perkin-Elmer).The activated prostasin monoclonal antibody (mAb) YL89 was one of the three prostasin mAbs initially generated using human milk-derived activated prostasin in complex with HAI-1 as the immunogen . The lacWe have previously successfully generated antibodies that are selective for the activated form of a protease using a protease-inhibitor complex as the antigen. In addition to several antibodies that recognize matriptase irrespective of its activation state, immunization of mice with matriptase-HAI-1 complex also allowed us to generate antibodies specific for the activated form of the enzyme which we have characterized extensively in our previous studies , 30, 32.in vivo zymogen activation status of prostasin and matriptase. More than 20 skin specimens were analyzed and consistent staining patterns were obtained using these mAbs. Prostasin was detected using the YL11 mAb primarily on cells of the granular layer  study of human skin frozen sections to determine and compare ar layer . At highar layer . The basar layer  to 2B. Ein vivo zymogen activation status of matriptase in human skin using sections from the same tissue sample in order to compare the distribution to that for prostasin. In marked contrast to the prostasin staining pattern, no matriptase staining was seen on the cells of the granular layer but was readily detected on the basal and spinous layers cells  and in the complexes with activated matriptase (120-kDa) or with activated prostasin (100-kDa), HAI-1 was also detected as 80-kDa and 50-kDa bands, which could represent the degraded products of HAI-1 or HAI-1 complexes.The high levels of zymogen activation in marked contrast to the situation for matriptase in the skin. Matriptase was detected predominantly in its 70-kDa zymogen form in the four foreskin lysates (Although HAI-2 has been identified as a major protease inhibitor of prostasin in human intestinal tissues and cultured colon carcinoma cells  and as aThe limited role of HAI-2 in the control of matriptase and prostasin could be the result of its tissue distribution and subcellular localization. To investigate this possibility, IHC analysis of human skin sections was conducted using the HAI-1 mAb DC16. HAI-2 staining was observed in the basal and spinous layers but not in the granular layers . At highIn contrast to the intracellular localization of HAI-2, HAI-1 was detected on the surface of the keratinocytes in all three viable epidermal layers . At highin vitro using HaCaT human keratinocytes (The different subcellular localizations of HAI-1 and HAI-2 can also be observed inocytes . Indirecinocytes  and HAI-inocytes . The imminocytes , the polin vivo zymogen activation status, the in vivo and in vitro subcellular localization, and the level of protease-protease inhibitor complexes demonstrated in the current study provide important information that informs an assessment of the putative functional relationship between matriptase and prostasin and between the two proteases and HAIs in human skin. A close functional linkage between the two serine proteases and among these proteases and protease inhibitors have been suggested by an array of previous studies using a variety of model systems. The proposed functional relationships include one involving a reciprocal activator-substrate interaction between matriptase and prostasin and another involving potent inhibition of matriptase and prostasin by HAI-1 and HAI-2. Our previous studies, however, suggested that though they may be correct in some contexts these proposed functional linkages can not be generalized and are somewhat tissue-selective or context-dependent [The tissue distribution, the ependent , 17, 18.ependent , a pieceThe tight control of matriptase zymogen activation in normal skin with activation seems to be limited to the basal layer, suggests its role may normally be limited to this important compartment. Increased matriptase zymogen activation has, however, been observed in a variety of distinct skin diseases, particularly those in which inflammation is involved . InflammThe regulated nature of matriptase zymogen activation and its confinement primary to the basal keratinocytes is in stark contrast to the high-level activation of prostasin that is predominantly observed in cells in the later stages of epidermal differentiation. The high levels of zymogen activation suggests that prostasin proteolytic activity is likely constitutive and that it participates in the maintenance of the epidermal renewal processes in quiescent human skin. The primary expression of this protease in the granular layer further suggests that prostasin proteolytic activity is involved in the late stages of epidermal differentiation, such as the processes involved in epidermal barrier formation.in vivo in human. The significant zymogen activation in conjunction with the lack of another functional protein domain suggests that prostasin’s physiological function, at least in the intestines, skin, prostate, and lactating mammary gland, is likely dependent on its proteolytic activity. The significant level of prostasin zymogen activation detected in vivo is at odds with the recent suggestion that prostasin zymogen and not prostasin enzymatic activity participates in the activation of several identified substrates and its biological functions [in vivo, prostasin enzymatic activity, the mechanism governing prostasin zymogen activation, and the inhibition of active prostasin by the HAIs represent important potential mechanisms for the regulation and subsequently the biological function of prostasin in vivo. These conventional protease regulatory mechanisms and the proteolytic activity are likely not applicable to the suggested biological functions of prostasin zymogen. If prostasin zymogen is the functional form for its biological functions, what would be the structural basis for prostasin regulation and functions?The detection of high levels of activated prostasin suggests that prostasin undergoes significant zymogen activation in quiescent human skin. In human intestine, the majority of prostasin was also detected in the activated form in complexes with HAI-1 or HAI-2 . Furtherunctions , 37–40.


Heavy metals are natural non-biodegradable constituents of the Earth's crust that accumulate and persist indefinitely in the ecosystem as a result of human activities. Since the industrial revolution, the concentration of cadmium, arsenic, lead, mercury and zinc, amongst others, have increasingly contaminated soil and water resources, leading to significant yield losses in plants. These issues have become an important concern of scientific interest. Understanding the molecular and physiological responses of plants to heavy metal stress is critical in order to maximize their productivity. Recent research has extended our view of how plant hormones can regulate and integrate growth responses to various environmental cues in order to sustain life. In the present review we discuss current knowledge about the role of the plant growth hormones abscisic acid, auxin, brassinosteroid and ethylene in signaling pathways, defense mechanisms and alleviation of heavy metal toxicity. During their lifetime, plants are affected by several environmental challenges that threaten survival and negatively influence their growth and productivity. Understanding how plants can translate the signals from an ever-changing environment into physiological behavior is essential for reducing harmful effects caused by abiotic stresses, such as heavy metal toxicity.Currently, the contamination of natural ecosystems by heavy metals represents a worldwide environmental concern, endangering agricultural systems , which impairs antioxidant defense systems and causes oxidative stress  can improve protection against heavy metal toxicity  is a multifunctional phytohormone that plays an important role during many stages of a plant's life cycle, including seed development and dormancy . This hoABA concentration in plant tissues is known to increase after heavy metal exposure, suggesting an involvement of this phytohormone in the induction of protective mechanisms against heavy metal toxicity  stress (Cicer arietinum) seeds under lead (Pb) toxicity conditions (Empetrum nigrum) exposed to Cu and nickel (Ni) (It was shown that cadmium (Cd) treatment leads to increased endogenous ABA levels in roots of OsNCED2 and OsNCED3, as well as the up-regulation of four ABA signaling genes under metal stress  stress has revealed strong expression of ABA biosynthesis genes 2+ and Zn2+ exposure, PYL, three PP2C and two SnRK2 genes that are putatively involved in ABA signal transduction. The expression patterns of these genes were also investigated, and the results showed that gene expression varied with the treatment being used. However, further studies are necessary in order to better understand how core component genes of ABA signal transduction mediate heavy metal stress through gene expression induction.The complex regulation of ABA is mediated by three main components of its signaling pathway, the PYL/PYR/RCAR, PP2C and SnRK2. In an attempt to clarify the transcriptional regulation of ABA signal transduction during cucumber seed germination under CuSince the ABA concentration increases in response to heavy metal stress, its potential role as a mediator of Cd-induced phytotoxicity was examined . ResultsDespite a lack of knowledge regarding the way in which the ABA signaling pathway changes in response to heavy metal exposure, a series of results indicate a strong correlation between high levels of ABA and a decrease in plant stress. Furthermore, some evidence has shed light on the functional significance of elevated hormone concentrations in plants exposed to heavy metal toxicity.ABA is normally considered a signaling compound, which can be extracted from roots subjected to drought conditions. Transported via xylem sap to the guard cells, where it closes stomata, this phytohormone prevents a decline in water potential and contributes to the plant's adaptation to unfavorable conditions . TherefoBrassica juncea under Cd2+ exposure  in the same Cd-tolerant rice seedlings. These results indicate that roots under heavy metal exposure accumulate ROS and Ca2+, which in turn activate MAP kinase, providing Cd tolerance. It is already known that ABA is able to induce transient MAP kinase activity  is often reported as an important mediator in several aspects of plant growth and development.Inside the cell, the hormone promotes the degradation of AUX/IAA transcriptional repressors that are associated to ARFs (auxin responsive factors) and thus inhibit the transcription of auxin-responsive genes ultimately guiding modifications in plant physiology .pin1 DR5rev::GFP mutants did not show enhanced auxin activity in both the meristem and elongation zones, indicating that PIN1 is involved in hormone distribution under heavy metal stress conditions. In a similar way, auxin distribution is also altered under boron (B) starvation, which leads to PIN1 down-regulation and possible inhibition of root elongation  and auxin in Cd-mediated inhibition of Arabidopsis root meristem growth has also been investigated  and the Brassica juncea  is able to alter levels of three auxins  in Helianthus annuus) plants grown in soil moderately contaminated with lead (Pb) was observed after the addition of the phytohormone IAA  and IAA or naphthalene acetic acid (NAA - another member of the auxin family) has been proposed to induce decreased disorder of membrane organization, and as a consequence, reduce heavy metal toxicity  moss These studies indicate a complex regulation of endogenous auxin in response to heavy metal exposure . It is pPlant steroids (brassinosteroids – BRs) regulate cell expansion and elongation, photomorphogenesis, flowering, male fertility, seed germination, vascular differentiation, plant architecture, stomata formation and senescence in plants . Sixty BIn addition to their significance in general plant growth and development, BRs perform a variety of physiological roles in guarding against abiotic stress, including high and low temperatures (2-), hydroxyl (OH-), perhydroxyl (HO2-), alkoxy (RO), as well as the non-radicals hydrogen peroxide (H2O2) and singlet oxygen (O2)  . Plant agen (O2) . It is w2+ ions can bind to proteins and lipids inducing oxidative damage  is another important environmental contaminant. High concentrations of Nie damage . ExogenoBrassica juncea by increasing activity of antioxidant enzymes   is known to be toxic even at a very low concentrations as it accumulates in edible parts of growing plants, thereby endangering crop yield and quality  is an essential transition metal, and an indispensable component in a diverse range of plant metabolic reactions. Furthermore, Cu has become increasingly hazardous due to its inclusion in fungicides, fertilizers and pesticides . Several studies have reported the involvement of this phytohormone in response to abiotic stress, and previous experiments have shown an increased production of ethylene in plants exposed to toxic levels of heavy metals  to form ethylene, CO2 and cyanide in plants  by SAM synthetase. SAM, as a substrate, is capable of forming 1-aminocyclopropane-1-carboxylic acid (ACC) by ACC synthase (ACS). This is the rate-limiting step in the ethylene biosynthesis pathway and ultimately releases 5′-methylthioadenosine (MTA), which is recycled again to methionine via the so-called “Yang cycle.” However, in the presence of On plants . The enzCopper (Cu) has been found to induce the expression of the ACS genes in potatoes, and in the same way, different varieties of tobacco accumulated ACS transcripts under Cu exposure -treated rice roots showed increased expression of four ethylene biosynthesis-related genes , indicating the participation of ethylene in Cr signaling in rice  for alleviating heavy metal stress, further research is expected to contribute to a deeper knowledge on the endogenous regulation of plant hormone metabolism in such harmful conditions. There are several studies already in support of the importance of plant hormones under heavy metal exposure as well as other abiotic stresses. It is also interesting to note that the critical plant tolerance achieved by phytohormones can be promoted directly or indirectly. For example, ethylene signaling is mediated by EIN2, and some studies also show that the EIN2 gene mediates Pb resistance through AtPDR12, an efflux pump at the plasma membrane. But phytohormone tolerance can also be induced indirectly, as the one promoted by brassinosteroids, which improves antioxidant systems efficiency in removing ROS and, as a consequence, attenuates detrimental effects from heavy metal stress. In the same way, hormonal treatments were not able to overcome the adverse effects of heavy metals on plant nutrient acquisition, but they were able to efficiently inhibit heavy metal incorporation, such as in stomatal closure guided by ABA that ultimately decrease toxic metals uptake and translocation from roots to shoots.Considering the importance of plant growth hormones (In summary, improving our knowledge of hormone metabolism in plants is critical for the development of new physiological, biochemical and biotechnological approaches towards mitigating the enormous spectra of abiotic stresses we see in today's environment, including heavy metal toxicity. With challenges such as climate change, which is expected to reduce crop yield in many areas, such information could prove critical for maintaining a reliable food supply for an ever-growing human population