Outflow tract banding was used to increase hemodynamic load in the chicken embryo heart between Hamburger and Hamilton stages 18 and 24 (~24 h during tubular heart stages). 3D focused ion beam scanning electron microscopy analysis determined that increased hemodynamic load induced changes in the developing myocardium, characterized by thicker myofibril bundles that were more disbursed in circumferential orientation, and mitochondria that organized in large clusters around the nucleus. Proteomic mass-spectrometry analysis quantified altered protein composition after banding that is consistent with altered myofibril thin filament assembly and function, and mitochondrial maintenance and organization. Additionally, pathway analysis of the proteomics data identified possible activation of signaling pathways in response to banding, including the renin-angiotensin system (RAS). Imaging and proteomic data combined indicate that myofibril and mitochondrial arrangement in early embryonic stages is a critical developmental process that when disturbed by altered blood flow may contribute to cardiac malformation and defects.Normal blood flow is essential for proper heart formation during embryonic development, as abnormal hemodynamic load (blood pressure and shear stress) results in cardiac defects seen in congenital heart disease (CHD). However, the detrimental remodeling processes that relate altered blood flow to cardiac malformation and defects remain unclear. Heart development is a finely orchestrated process with rapid transformations that occur at the tissue, cell, and subcellular levels. Myocardial cells play an essential role in cardiac tissue maturation by aligning in the direction of stretch and increasing the number of contractile units as hemodynamic load increases throughout development. This study elucidates the early effects of altered blood flow on myofibril and mitochondrial configuration in the outflow tract myocardium  The heart is the first functional organ in the embryo, and starts beating by the coordinated interaction of primitive myofibril bundles and energy supplying mitochondria as soon as the early heart tube is formed  stage 18  system was used to measure chick embryo band tightness Da is the maximum external diameter of the outflow tract at the band site after banding, and Db is the maximum external diameter of the outflow tract at the approximate band site location before banding. The measured band tightness of each banded embryo was used to define the hemodynamic environment, based on our previous characterization of the relationship between the degree of outflow tract band tightness and the specific blood pressure and velocity conditions induced , still corresponding to looping tubular stages of heart development. Samples were processed for focused ion beam scanning electron microscopy (FIB-SEM). FIB-SEM imaging was performed on an FEI Helios 660 NanoLab™ DualBeam™. Whole embryos were removed from the egg and immediately immersed in fixative  to maximally preserve and contract the tissue  was used for all FIB-SEM image registration, processing and quantification. First, the acquired image stacks were automatically aligned to reconstruct the 3D image volume. Myofibril bundles, mitochondria, nuclear, and extracellular material were then manually segmented (for consistency) from 500 image stacks and reconstructed, in order to quantify organelle 3D volume and organization.Myofibril and mitochondrial volume fractions in the cell cytoplasm  were used to quantify organelle volume, which accounted for differences in sample nuclear volume that depended on the specific region of interest. Cytoplasm volume was calculated by subtracting the volume of extracellular and nuclear material from the total sample volume. Myofibrils were additionally quantified by bundle thickness and orientation within the outflow tract. Myofibril bundle thickness was used as a measure of the extent of myofibril development, and quantified as the average of measured lengths of Z-lines of all bundles in each sample. Myofibril bundle orientation was quantified in terms of angles ϕ and θ  and 5 sham control samples included in these experiments, with each sample consisting of 8 pooled outflow tracts (40 hearts per treatment distributed into 5 samples). Pooling outflow tracts was necessary to reach the minimum mass required for the mass-spectrometry analysis. Samples were then processed as described before  with SEQUEST HT software and a Gallus gallus Ensembl database (release 85) containing 16,187 sequences. Searches were configured with static modifications for the TMT reagents (+229.163 peptide N-terminus and K residues) and iodoacetamide (+57.021 C residues), variable oxidation (+15.995 M residues), parent ion tolerance of +/− 1.25 Da, fragment ion tolerance of 1.0 Da, monoisotopic masses, and trypsin cleavage (max 2 missed cleavages). Searches used a reversed sequence decoy strategy to control peptide false discovery and identifications were validated using Percolator software. Only peptides having mass errors <20 ppm, and matching only one protein entry in the database were used. Search results and TMT reporter ion intensities were exported as text files and processed using in-house scripts. After excluding the highest and lowest reporter ion intensities, an average intensity >500 was required for the remaining reporter ions to exclude the analysis of peptides with insufficient signal intensity. Reporter ion intensities for peptides assigned to each protein were then summed to create an abundance measurement for each protein across the 10 samples simultaneously analyzed.t-test, assuming significance with two-tail p < 0.05 unless otherwise noted.FIB-SEM samples and TMT samples were selected with a relatively small range of band tightness (30–45%), and therefore differences between samples with varying band tightness were not analyzed. Rather, analysis was performed to determine differences between control and banded samples. Statistical significance between banded and control groups using FIB-SEM image analysis was determined with a two-sample Student's p-values, Benjamini–Hochberg multiple test correction to calculate false discovery rates  during tests for differential abundance for each protein compared between banded and control samples. These data was used in comparing changes in abundance of specific proteins.Differential protein abundance was determined in the TMT experiment by comparing the summed peptide reporter ion intensities for each protein across samples (5 control and 5 banded) using the R software (v 3.1.1) package edgeR , as described above using edgeR. We then filtered the data for low intensity values and peptide counts per protein: we discarded protein measurements with low intensity  and proteins obtained using only one peptide. That is, for analysis we kept only proteins that were relatively abundant and measured with accuracy. This rendered 3838 proteins of which 2,544 could be mapped to known proteins/genes in IPA. The filtered data  were used as input for the IPA analysis . IPA rendered a list of affected canonical pathways with their p-values, which measure statistically significant overlap between the dysregulated input-gene dataset and genes in the pathway, and was calculated using Fisher's exact test. Regulation direction, however, is not considered into the calculation of the pathway p-value, and is included instead in the z-scores. The z-score in IPA is defined asA pathway analysis of proteomics data was performed using Ingenuity Pathway Analysis (IPA) software (Qiagen Bioinformatics). Protein intensities quantified for each sample (5 control and 5 banded) were used to compute differential protein abundances and protein fold ratios (and their logarithms) between banded and control treatments, as well as + and N− are proteins that have changed abundance in the direction of pathway activation and inhibition (according to literature-derived regulation direction incorporated in IPA), respectively. Pathway z-scores therefore quantify activation or inhibition of pathways based on the differential abundance of detected proteins in the pathway.where N is the number of detected dysregulated proteins in the pathway, NFIB-SEM processing acquired 3D image data from the myocardium layer of the heart at HH24 with excellent myofibril and mitochondrial ultrastructural detail. Control outflow tract myocytes contained immature myofibril structures Figure  and instp = 0.17, n = 3). Similarly, mitochondrial-cytoplasm volume fraction was comparable in both groups .To quantify alterations in myofibril and mitochondrial volume after outflow tract banding, these organelles were segmented from high-resolution FIB-SEM image volumes of myocardial outflow tract tissue. Myofibril and mitochondrial volume fraction in the cell cytoplasm were calculated from the 3D reconstructions of the segmented images Figure . The myo3D FIB-SEM reconstructions of myofibril bundle segmentations were used to calculate fibril bundle thickness and orientation. While myofibril volume fraction and orientation in the radial plane . Box plots show that there was a larger range of bundle thicknesses in banded samples, indicating that these samples had both small and abnormally large bundles . The full proteomics data set was deposited in the PRIDE repository database (ProteomeXchange Consortium), with dataset identifier PXD005362. A volcano plot of the data is shown in Figure TMT based mass spectrometry provided a proteome-wide assessment of changes in the relative abundance of specific proteins induced by increased hemodynamic load. Specifically, we first focused on examining changes in proteins known to be markers of myofibril and mitochondrial reorganization. A total of 5,330 proteins were detected in the outflow tract samples, where the abundance of 606 proteins significantly differed between banded and control samples , and that were either significantly activated or inhibited , when performing the analysis using only dysregulated proteins with p < 0.1  and could indeed be indispensable for cardiac development , validation would be required to show pathway activation/inhibition in response to banding.p < 2 · 10−4) and the angiotensin I converting enzyme . These upstream effectors initiate signaling through angiotensin II (Ang II) after converting AGT into Ang I and then Ang II. Downstream proteins, in addition, were also affected. In particular STAT3 increased 1.2-fold in banded hearts compared to controls (p < 0.002). Nevertheless, due to the relatively low number of proteins detected in the RAS pathway, validation of pathway activation needs to be performed in future research. RAS is known to play an important role in the response of the fetal and mature heart to pressure, and its involvement could be pivotal in heart development.In the RAS pathway, we found increase in abundance of upstream regulators. In particular, we found an increase in angiotensinogen . Both the Mitochondrial dysfunction and Oxidative phosphorylation pathways are related to regulation of mitochondrial function and showed a reduction in components of the mitochondrial complexes I, IV, and V, as well as a (a weaker) reduction in Complex III. While z-scores for these pathways were not available since there was not enough information on the IPA database to determine pathway activation status, the Molecule Activity Predictor (MAP) tool available in IPA predicted decrease of ATP production associated with these pathways. The EIF2 signaling pathway, in contrast, was activated (z-score 1.9) and it is associated with global protein synthesis and regulation of mRNA. MAP applied to the EIF2 signaling pathway predicted increased cardiac protection, as well as increase amino acid transport and synthesis. Interestingly, and in connection with mitochondrial function, we found significant decreases in the cAMP-responsive element binding 1 (CREB1) protein ; and in the mitochondrial transcription factor A .Other canonical pathways highlighted in our analysis were the “Mitochondrial Dysfunction,” “EIF2 Signaling,” and “Oxidative Phosphorylation” pathways , these results taken together with the proteomic data indicate an organizational myofibril and mitochondrial response to increased hemodynamic load.Even though myofibril and mitochondrial volume fraction is unchanged after increased hemodynamic load, altered myofibril and mitochondrial organization suggest that abnormal hemodynamics induced by banding interferes with the normal myocardial cell maturation process. Unchanged organelle volume fractions after banding is consistent with a study by Clark et al. that found similar organelle proportion of myofibrils and mitochondria, DNA-to-protein ratio, and myocyte area after outflow tract banding at HH21 and concluded that measured increases in ventricular weights were due to myocyte hyperplasia  and then they were cultured for 48 h. Addition of Ang II in the cultured media resulted in increased myofibril development in the heart. Ang II treated hearts exhibited more advanced sarcomere and Z-band organization, which resembled the increased myofibril development that we observed in our banded hearts with respect to controls. Thus our data, in view of previous studies, may imply that myofibril reorganization after increased hemodynamic load in banded hearts may be mediated by RAS. While this relationship will need to be further validated, especially given the low number of proteins in RAS detected by the proteomics analysis, it is certainly an exciting possible direction of research.Analysis of mass-spectrometry data combined with pathway analysis, revealed increases in the abundance of proteins associated with the RAS pathway with banding. In adults, RAS is a key regulator of blood pressure  proteins. Since the great majority (99%) of mitochondrial proteins are encoded in the nucleus, transport of cytosolic proteins plays an important role on mitochondrial function (Boengler et al., Several mitochondrial protein abundances were altered in banded samples including components of mitochondrial maintenance, organization, and the electron transport system. Proteins with roles in mitochondrial fission or fusion and cell death were detected by the TMT experiment, although they were largely unchanged in banded samples compared to controls. These proteins included Dynamin-1-like protein, optic atrophy type 1, mitochondrial fragmentation-causing death-associated protein 3, and dynamin-related protein 1 (Chen et al., The EM imaging and proteomic data taken together indicate that hemodynamic forces induced by banding after only 24 h of intervention interfere with normal development of the outflow tract myocardium. The specific molecular mechanisms by which this happens, while likely complex, remain to be elucidated and deserve additional research efforts. Interestingly, however, our data points toward the embryonic activation of the RAS pathway, known to be active in cardiac dysfunction later in life, as a possible mechanism inducing myocardial reorganization and cardiac defects in response to increase hemodynamic load. This study indicates that normal myocardial and mitochondrial reorganization is one of the initial processes affected by increased hemodynamic load, which induces a detrimental cascade of events that eventually leads to cardiac defects.MM coordinated the study, carried out a large portion of the data collection and data analysis, and drafted the manuscript; CL carried out the work done in the Multiscale Microscopy Core in the OHSU Center for Spatial Systems Biomedicine and contributed to the manuscript; LD carried out the work and data analysis done in the OHSU Proteomics Core and contributed to the manuscript; AM helped with IPA analysis, SR conceived of the study and helped draft the 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.


In the healthy brain, the physiological opening of astrocyte hemichannels modulates basal excitatory synaptic transmission. At the other end, the release of potentially neurotoxic compounds through astroglial hemichannels and pannexons has been insinuated as one of the functional alterations that negatively affect the progression of multiple brain diseases. Recent insights in this matter have suggested encannabinoids (eCBs) as molecules that could regulate the opening of these channels during diverse conditions. In this review, we discuss and hypothesize the possible interplay between the eCB system and the hemichannel/pannexon-mediated signaling in the inflamed brain and during event of synaptic plasticity. Most findings indicate that eCBs seem to counteract the activation of major neuroinflammatory pathways that lead to glia-mediated production of TNF-α and IL-1β, both well-known triggers of astroglial hemichannel opening. In contrast to the latter, in the normal brain, eCBs apparently elicit the Ca Because neurons are the excitable cells responsible for the transmission of electrochemical impulses during major cognitive processes, they were considered for a long time the main functional units at the central nervous system  during physiological and pathological conditions , whose major structural features include the presence of four highly conserved transmembrane domains, two extracellular loops, intracellular N- and C-termini and a cytoplasmic loop linking the second and third transmembrane segments  causes similar effects in these channels  or Ca2+ itself  has been widely used throughout history for medicinal, religious, recreational and social purposes, just in the past two decades research in the field has brought to light its multiple benefits  and immune cell in the periphery, such as macrophages, neutrophils, lymphocytes, natural killer cells and monocytes , BBB breakdown and subsequent brain infiltration of circulating immune cells characterize this process  is the sorting of hemichannels to the cell surface. For instance, WIN fully abolish the Aβ-induced augment in surface levels of Cx43, signifying that modifications in surface expression of this protein may account for the preventive effects of CBs , bestrophin-1 Ca2+-activated chloride channels, pannexons, hemichannels and transporters -mediated IP3 production, indicating the involvement of Gq proteins rather than a “classical” inhibition of adenylate cyclase -mediated slow inward currents (SIC) in proximal pyramidal neurons  when it coincides with the postsynaptic release of NO (Gómez-Gonzalo et al., 1 receptors in local homoneuronal synapses (Wilson and Nicoll, in vivo or whether they occur only in specific physiological or pathophysiological circumstances.The involvement of astroglial CB2+]i-dependent vesicular fusion of either large or small synaptic-like vesicles (Araque et al., 2+ entry that subsequently activates other [Ca2+]i-dependent gliotransmitter release pathways (Montero and Orellana, 2+ to concentrations that take place during neuronal bursting activity, causes ATP efflux via astroglial Cx43 hemichannels, which subsequently strengths inhibitory transmission by activation of neuronal P2Y1R (Torres et al., While a lot has been learned about the role of astrocytes on eCB-mediated synaptic plasticity, how exactly gliotransmitters are released from astrocytes is uncertain but it could involve vesicular exocytosis in some cases. Using the light chain of tetanus toxin and Evans blue, an inhibitor of the vesicular glutamate transporter, Min and Nevian  demonstr2+]i in astrocytes decreases NMDA but not AMPA postsynaptic currents in the prefrontal cortex (Meunier et al., 2+]i oscillations in astrocytes (Henneberger et al., Additionally, when studied in basal conditions, the opening of astroglial Cx43 hemichannels enhances the amplitude of slow oscillations in mitral cells of the olfactory bulb (Roux et al., 2+]i-dependent release of glutamate and D-serine from astrocytes (Navarrete and Araque, in vivo microscopy, Vázquez et al. (1-dependent elevation of [Ca2+]i in astrocytes relies on PLC activation and further IP3 production (Navarrete and Araque, 2+ according to a bell-shaped “convex-up” pattern, with maximal activity in the 500 nM range and decreasing activities at both higher and lower [Ca2+]i (De Bock et al., Overall, the above studies provide a solid picture about the role of astroglial hemichannels in synaptic transmission and thus their involvement on eCB-mediated neural plasticity could be critical. How hemichannels may contribute to the eCB-dependent synaptic dialog between astrocytes and neurons? Given that postsynaptic eCBs cause the i may contribute to perpetuate [Ca2+]i-induced Ca2+ entry pathways associated to ATP release. Altogether, these data highlight that ATP signaling via purinergic receptors, hemichannels and pannexons may represent a plausible mechanism for underlying the CB1-dependent astroglial modulation of synaptic transmission and plasticity (Figure 2+ responses in astrocytes (Fields and Burnstock, 2+]i over 500 nM (Meunier et al., Another angle not mentioned so far is the eventual contribution of connexin/pannexin-dependent widespread of astrocyte Cay Figure . Desensi+ channels (Kawamura et al., In addition to contributing to astroglial-mediated release of gliotransmitters, Panx1 channels may also regulate synaptic communication given its broad expression and functionality in neurons (Thompson, As we noted before, it seems that the outcome of CBs in the functional activity of hemichannels will depend on the physiological status of the brain. Namely, under physiological conditions, eCBs may induce the controlled opening of astrocyte hemichannels and the consequent release of gliotransmitters. This may be particularly relevant for transient or long-lasting mechanisms of synaptic transmission and plasticity evoked by eCBs. At the other end, in the inflamed brain, eCBs may counteract the dysfunctional opening of hemichannels by triggering a large-scale of anti-inflammatory pathways that result in the inhibition of hemichannels and stimulation of astroglial coupling. The exact scenario and cellular cascades by which eCBs lead to this dual opposite regulation of hemichannels remain uncertain. Nevertheless, part of the explanation may rely in that eCBs may have different outcomes depending on which CB receptor they are exerting their actions. Additionally, the altered expression and production of CB receptors and eCBs during pathological conditions, respectively, may trigger different pathways that oppositely regulate the function of hemichannels. Considering the recent evidence linking the activity of GJCs, hemichannels and pannexons with major depression, addiction, autism, epilepsy and schizophrenia (Sarrouilhe et al., JAO: conceived and designed the major ideas developed in the manuscript. VCL, CAS, RG-G, EFD, GIG and JAO: reviewed the literature and designed the figures; wrote and edited the manuscript. All authors 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.


Accumulating evidence shows that Ca2+ elevations regulate the release of gliotransmitters that, in turn, modulate synaptic transmission and neuronal excitability. Recent studies also provided new insights into the spatial and temporal features of astrocytic Ca2+ elevations revealing a surprising complexity of Ca2+ signal dynamics in astrocytes. Here we discuss how recently developed experimental tools such as the genetically encoded Ca2+ indicators (GECI), optogenetics and chemogenetics can be applied to the study of astrocytic Ca2+ signals in the living brain.Sensory information processing is a fundamental operation in the brain that is based on dynamic interactions between different neuronal populations. Astrocytes, a type of glial cells, have been proposed to represent active elements of brain microcircuits that, through dynamic interactions with neurons, provide a modulatory control of neuronal network activity. Specifically, astrocytes in different brain regions have been described to respond to neuronal signals with intracellular Ca Here we summarize the innovative techniques to study neuron-astrocyte interactive networks in vivo, describe advantages and limitations and discuss possible future developments in this field.Brain function is based on complex networks composed of different, highly interacting cell populations. The activity of principal projecting neurons is locally regulated by different classes of interneurons  and one or two fluorescent proteins and are extensively used for studying astrocyte physiology in vivo. Several tools are used to express GECIs in astrocyte: mouse lines expressing Cre recombinase under the control of specific promoters (glutamate aspartate transporter (GLAST), glial fibrillary acidic protein (GFAP) or S100 calcium-binding protein B (S100β) crossbred with GCaMP-floxed mice represent a non-invasive method to express GECIs in a subpopulation of astrocytes , that can be activated by selective agonists devoid of endogenous targets  pump inhibitors, such as cyclopiazonic acid (CPA), or by using a transgenic mouse lacking IP3 receptors in astrocytes (Srinivasan et al., 2+ signaling in astrocytes in vivo (Xie et al., on demand rapid and effective silencing of astrocyte Ca2+ signals is highly desired, such implements have yet to come.However, both chemogenetics and optogenetics have drawbacks that must be taken into account (see Table 2+ imaging techniques in vivo, will allow greater understanding of astrocyte functions in the brain.Almost a century of neuron-centric research has left a deep gap in our knowledge of astrocyte physiology. The role of astrocytes in brain function and dysfunction emerged as a major topic in neuroscience in the last decade after the recognition of their dynamic modulation of synaptic functions and the evidence of their involvement in the early stages of neurological disorders, including epilepsy, ischemia, Alzheimer’s and Parkinson’s diseases Barres,  making aGL and GC wrote the abstract, introduction, selective tools to study neuron-astrocyte cross-talk, conclusion and supervised the manuscript. LM wrote the paragraph on Imaging techniques. MS wrote the paragraph on calcium sensitive dyes and Table 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.


Drug classes used in the treatment of Chronic Obstructive Pulmonary Disease (COPD) have not changed for many years, and none to date have shown disease-modifying activity. Statins are used to help reduce cardiovascular risk, which is high in many patients with COPD. Their use has been associated with improvements in some respiratory manifestations of disease and reduction in all-cause mortality, with greatest reductions seen in patients with the highest inflammatory burden. The mechanism for these effects is poorly understood. Neutrophils are key effector cells in COPD, and correlate with disease severity and inflammation. Recent in vitro studies have shown neutrophil functions are dysregulated in COPD and this is thought to contribute both to the destruction of lung parenchyma and to the poor responses seen in infective exacerbations. In this article, we will discuss the potential utility of statins in COPD, with a particular emphasis on their immune-modulatory effects as well as presenting new data regarding the effects of statins on neutrophil function in vitro. COPD is a chronic inflammatory condition of the lungs associated with significant systemic manifestations and co-morbidities . It is dOf all the co-morbidities associated with COPD, one of the most important is cardiovascular disease (CVD). COPD patients have a higher risk of CVD than people without COPD ,4, even COPD is now the third leading cause of death world-wide  and is aThere are currently no disease modifying medications in COPD, and the mainstay of treatment remains bronchodilators and generic anti-inflammatory corticosteroids, although there is controversy about their high utility in this disease . There iCOPD is associated with an abnormal, chronic, and injurious inflammatory response . A largeNeutrophils are the dominant circulating leukocyte and represent a key component of the innate immune system. In response to infection/inflammation, neutrophils leave the circulation and migrate to sites of infection where they utilise a variety of mechanisms to contain and kill invading pathogens. This includes phagocytosis, degranulation, production of reactive oxygen species (ROS), and release of neutrophil extracellular traps (NETs).l-selectin and integrins such as CD11a/CD18 on the neutrophil, supporting neutrophil capture and transmigration through endothelium into the tissues [2) into Phosphatidylinositol -triphosphate (PIP3) which has downstream effectors that induce F-actin polymerisation and protrusion of actin filaments from the neutrophil membrane; thus creating a pseudopod [3, preventing actin polymerisation but also deactivating integrins [Neutrophils are recruited to areas of inflammation by responding to inflammatory mediators released from inflamed or infected tissue, such as Interleukin 8 (CXCL8) and leukotriene B4 (LTB4). Laminar blood flow through post capillary venules forces heavier leukocytes (including neutrophils) against the endothelial walls. During inflammatory events, endothelial cells upregulate the expression of selectins  and intercellular Adhesion Molecule (ICAM) adhesion molecules on their luminal surfaces  which bi tissues . Before  tissues ,24. Pseuseudopod . SHIP1 antegrins .3 gradient, polarising the neutrophil [For a neutrophil to migrate in the correct direction, it must have higher PI3K activation in the area of the cell facing the chemical gradient (leading edge) and higher SHIP1, PTEN activation (to impede PI3K activity) on cell surfaces opposite to the leading edge (the uropod). This creates an anterior posterior PIPutrophil . The actutrophil .Cigarette smoke (CS) contains a multitude of toxic products and is thought to initiate the inflammatory processes within the lungs in COPD in most patients . InitialOnce neutrophils reach their target sites, they have a number of methods to remove bacterial colonies and cell debris in the lung; phagocytosis, degranulation and release of antimicrobial peptides, respiratory burst (release of ROS), and NETosis .Phagocytosis is a receptor mediated process whereby the neutrophil binds bacteria through IgG and complement opsonisation or Pathogen Associated Molecular Patterns (PAMPs)  before eNETs are extracellular DNA meshworks laden with azurophillic and specific granule proteases and histones which neutrophils release in some inflammatory environments. The NET effectively captures microbes and provides a platform for bacteriocidal proteinases and histones . NET relInitially, there was controversy as to whether the sustained neutrophilic inflammation present in COPD was a ubiquitous response to the inflammatory environment caused by CS , or whether neutrophil functions, and the resultant inflammation, were dysregulated in COPD, and a fundamental component of disease. There is a building body of evidence to support the latter hypothesis. Only a quarter of smokers develop clinically significant COPD  and smok3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG CoA) Reductase Inhibitors (commonly referred to as “Statins”) are primarily indicated for the treatment of dyslipidaemia, to reduce cardiovascular risk. The evidence supporting statin-associated CVD risk reduction is extremely robust  and staHowever, evidence has consistently shown that statins reduce all-cause mortality irrespective of baseline low-density lipoprotein (LDL) cholesterol ,63 with In addition to reducing cholesterol synthesis, statins also reduce production of all products downstream of HMG-CoA, including inhibition of isoprenoid production. Isoprenoids are utilised by cells for the post-translational modification and activation of small GTP-ases such as Ras and Rho; molecules that are essential for a number of inflammatory cellular functions including adhesion, cell recruitment, and immune cell de-granulation ,66  and tumour necrosis factor alpha (TNFα) concentrations predictive of cardiovascular events ,81. TherNeutrophilic inflammation is a central component of atherosclerosis ,87 and tMany of the inflammatory processes associated with CVD (and described above) have also been described in the pathology of COPD, where pulmonary and systemic inflammation is also significantly raised . In lighThere are an increasing number of studies examining the potential impact of statin use in COPD. Observational studies of COPD have described a slower decline in pulmonary function in patients taking statins ,98. FurtHowever, these results have not been universally replicated and some studies have shown no benefit  includinAll statins studied have shown some anti-inflammatory outputs in keeping with their shared mechanism of action and therefore the choice of statin does not appear important in studies reported to date. Current evidence points to a high dose being associated with improved inflammatory outcomes. Simvastatin (5–20 mg/kg) used with inhalation injury in mice was effective in attenuating lung damage but only at the higher dose . In a doThe patient group under study is also likely to be important. The recently reported STATCOPE study randomised COPD patients to receive 40 mg Simvastatin to determine impact on exacerbation rates. Inclusion criteria included a diagnosis of COPD and the use of supplemental oxygen, receipt of systemic glucocorticoids or antibiotic agents for respiratory problems, or presentation to the emergency department or hospitalization for COPD exacerbation in the preceding year  but freqFinally, the endpoint is likely to be crucial. It is unlikely that statins will act as a panacea for all manifestations of COPD or all inflammatory processes. Dysregulated neutrophil functions have been associated with tissue damage in COPD, particularly functions associated with increased or indiscriminate neutrophil elastase activity, which in turn has been associated with emphysema. If neutrophils are central to the development of COPD, one would expect a disease-modifying drug to impact positively on these functions, and there is evidence to support this. In a small controlled trial, statin therapy was associated with a decrease in sputum leptin, absolute neutrophil counts, and the incidence of COPD exacerbations .Previously, we identified increased migratory speed of movement in any direction (termed chemokinesis) but reduced migratory accuracy towards inflammation (termed chemotaxis) in systemic neutrophils isolated from patients with COPD and related this to systemic neutrophil elastase activity and the potential for tissue damage . We haveNeutrophils were incubated with Simvastatin sodium salt  at 1 nm or 1 µm or vehicle control (dimethyl sulfoxide) or buffer (negative control) for 40 min prior to migration studies and statin concentrations were chosen to represent known steady-state plasma concentrations of Simvastatin from 10 mg to 80 mg . ApproprThese results are in keeping with other in vitro assessments of the ability of statins to impact upon pro-inflammatory events. Importantly in the studies described above, simvastatin did not inhibit the ability of the cell to respond to infection/inflammation but rather improved it, however there have not been studies of statin use and NETosis, phagocytosis, or ROS release in neutrophils from COPD patients, and these would be needed to further assess the likely impact of statins on crucial neutrophil functions. Evidence from other in vitro human studies have described potential impairment of neutrophil bactericidal functions, but these have used non-therapeutic concentrations (such as 10–50 µm rather than the therapeutic 1 µm ) making COPD remains a significant cause of mortality and morbidity globally, and our therapeutic tools for reducing its impact are limited. There is clear evidence of improved CVD morbidity and mortality in COPD following statin use, but the shared inflammatory mechanisms that have been described in both COPD and CVD provide theoretical reasons to support the use of statins in COPD progression as well. Statins have been associated with improved lung outcomes in in vitro experiments, in animal models, and in observational studies of COPD. However, results of randomised controlled trials have shown limited efficacy on COPD-related outcomes such as exacerbation frequency. Disparity in COPD-related results may reflect experimental design and the patients and outcomes that were selected. The persistent signal reported in many studies has maintained interest in these drugs for this debilitating disease. Further in vitro studies and proof of principle clinical trials using statins at high doses—with cellular as well as clinical outcomes—in carefully selected patients may provide more insight into their potential utility.


To meet the challenges of increasing antimicrobial resistance, the infectious disease community needs innovative therapeutics. Precision medicine and immunotherapies are transforming cancer therapeutics by targeting the regulatory signaling pathways that are involved not only in malignancies but also in the metabolic and immunologic function of the tumor microenvironment. Infectious diseases target many of the same regulatory pathways as they modulate host metabolic functions for their own nutritional requirements and to impede host immunity. These similarities and the advances made in precision medicine and immuno-oncology that are relevant for the current development of host-directed therapies (HDTs) to treat infectious diseases are discussed. To harness this potential, improvements in drug screening methods and development of assays that utilize the research tools including high throughput multiplexes already developed by oncology are essential. A multidisciplinary approach that brings together immunologists, infectious disease specialists, and oncologists will be necessary to fully develop the potential of HDTs. Mycobacterium tuberculosis (Mtb) infection, was mainly on an empirical basis. Choosing next-generation HDT candidate agents for evaluation needs to be based on knowledge of the host regulatory signaling pathways that are disrupted by pathogens and identifying specific pathway molecules that can be therapeutically targeted.With increasing resistance to current antibiotics and reduced investment in the development of new antimicrobial drug classes, The World Health Organization has warned that we are at risk of entering a “post-antibiotic era” . The seaOncology has addressed similar challenges, i.e., reversing disruptions in cell regulatory mechanism that cause malignancies and often lead to suppression of immune processes. In response, oncologic research has developed innovative therapeutic approaches based on discoveries of basic pathogenic mechanisms of malignancies . These sHelicobacter pylori, Trypanosoma cruzi, and HIV to enhance their survival  concerning precision medicine in a commentary, “A New Initiative on Precision Medicine” “… this new understanding of oncogenic mechanisms has begun to influence risk assessment, diagnostic categories, and therapeutic strategies, with increasing use of drugs and antibodies designed to counter the influence of specific molecular drivers. Many targeted therapies have been (and are being) developed, and several have been shown to confer benefits, some of them spectacular.”  Pathogensurvival , 6. Somesurvival .+ T lymphocytes, and Th1/Th17 versus Th2 CD4+ T cells.Research evaluating the role metabolism plays in controlling immune functions (immunometabolism) has dramatically improved understanding of immune cell differentiation and regulation and lead to identification of novel immunotherapies. In immune cells, AMP-activated protein kinase (AMPK), sirtuins (SIRT), hypoxia-inducible factor-1α (HIF-1α), and mechanistic target of rapamycin (mTOR) are examples of signaling molecules that are essential “metabolic checkpoints” conserved in some form among all eukaryotic cell lineages. They regulate switches between highly active (aerobic glycolysis) and quiescent  metabolic states . Other cFrancisella tularensis and Pseudomonas aeruginosa downregulate HIF-1α to inhibit glycolysis and with it inflammatory cytokine production (Streptococcus pyogenes and Mtb both produce glycohydrolases that deplete nicotinamide adenine dinucleotide (NAD+), a key metabolite in macrophage function  and pembrolizumab (PD-1), to reverse immune exhaustion and improve tumor responses. Various antagonists of suppressive co-receptors and agonists of stimulatory co-receptors, including OX-40 and 4-1BB, are in use or being investigated for treatment of several malignancies and to enhance cancer vaccine responses . The regex vivo inhibition of PD-1 improved responses of T cells obtained from humans with pulmonary tuberculosis. Adding to the complexity is a recent study indicating that unlike the L1 ligand, the L2 ligand of PD-1 plays an essential role in establishing CD4+ T-cell mediated immunity in a malaria model  and Tregs. These cells have several immunomodulatory effects, including downregulation of cytokine and chemokine expression, cell trafficking, antigen processing and presentation, and autophagy Figure C. SuppreHotchkiss and Moldawer, in their article, “Parallels between Cancer and Infectious Disease,” point out the similarities in changes in regulation of immune responses to malignancies and infectious pathogens that involve modulation of common signaling pathways. They also noted that immunomodulatory therapies for infections may lead to an over-reactive immune response and excess tissue damage . Both prTo develop such assays, the fundamental regulatory molecular disruptions causing the immunologic defects must be precisely identified. Oncologic research has utilized cutting edge tools for high throughput multiplex  analyses of single cells from heterogeneous populations. Studies utilizing these methodologies, including CHiP analyses and DNA methylation mapping of epigenetic factors, will be essential for the identification of targets for further development as HDTs against pathogens.in vitro cell line infection models have yielded poor results. Improved in vitro screening models, for example, human multiple cell type-based 3-D granuloma models for TB, will need to be developed. Re-purposing of HDT drugs now in the clinic for therapy of many non-infectious diseases is a practical approach to address the lack of financial incentive to develop novel antimicrobial agents due to the high cost and lengthy development time needed for marketing approval of new drug classes versus limited financial return.Support for research to identify these specific immune cell core regulatory pathway disruptions caused by pathogens must be greatly increased to efficiently develop new HDTs for treatment and prevention. Also, drug screening methods are needed to identify which of the dozens of molecularly targeted HDT drug classes now in clinical use or evaluation for other diseases may be effective for infectious diseases. However, current screening methods using As pointed out by Dr. Collins, one goal of the precision medicine initiative is to “… instigate the next generation of scientists to develop novel approaches to be applied to a wide range of diseases with multidisciplinary approaches”  In orderRM and RH contributed equally to the development and writing of the paper, reviewing relevant literature, and preparation of figure in the paper.This manuscript was written by one of the authors as a National Institute of Allergy and Infectious Diseases (NIAID) employee, but the views expressed in this manuscript do not necessarily represent those of NIAID.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.


The influenza virus circulates yearly and causes global epidemics. Influenza infection affects all age groups and causes mild to severe illness, and young infants are at particular risk for serious disease. The most effective measure to prevent influenza disease is vaccination; however, no vaccine is licensed for use in infants younger than 6 months old. Thus, there is a crucial need for other preventive strategies in this high-risk age group. Influenza vaccination during pregnancy protects both the mothers and the young infants against influenza infection. Vaccination during pregnancy boosts the maternal antibodies and increases the transfer of immunoglobulin G from the mother to the fetus through the placenta, which confers protection against infection in infants too young to be vaccinated. Data from clinical trials and observational studies did not demonstrate adverse effects to the mother, the fetus, or the infant after maternal influenza vaccination. We present the current data on the effectiveness and safety of influenza vaccination during pregnancy in preventing disease in the young infant. The highest burden of severe illness is concentrated in those younger than 1 year old and older than 65 years old4. Neonates and infants are especially susceptible because they are naïve to past influenza virus infections and immunologically immature8.Influenza is a contagious, acute viral illness of the respiratory tract. The World Health Organization (WHO) estimates that during normal seasonal epidemics 5–15% of the population is typically infected by influenza viruses and that there are 3 to 5 million cases of severe illness and up to 500,000 influenza-associated deaths per year globally9. Nonetheless, efforts to protect infants from influenza infection during the first 6 months of life through direct vaccination have been unsuccessful with the available influenza vaccine formulations. Although safety was not a concern in the four published studies on inactivated influenza vaccines (IIVs) in infants younger than 6 months old13, immune responses to the vaccine were in general weak and attenuated possibly by the high levels of maternal antibodies12. Studies with live attenuated influenza vaccines in infants reported rates of seroconversion similar to those observed with IIV, but a higher number of adverse effects was reported16. Furthermore, vaccination schedules—with the exception of Bacille Calmette-Guérin, polio, and hepatitis B—start at only 6–8 weeks of age because of the inability of neonates to develop robust immunity17. Generally, this has been attributed to the absence of a strong type 1 T-helper cellular response, cytotoxic responses, trends to immunoregulatory responses, and weak plasma cell and germinal B-cell responses early in life18.Vaccination is the best way to prevent influenza illness. Safe and effective vaccines are available and have been used for more than 70 years in the general population22. Therefore, efforts have turned to active vaccination during pregnancy as a means to provide neonates and young infants with passive immunity to influenza. Based on the substantial risk of severe disease in young infants and the safety of influenza vaccine during pregnancy, the WHO, the US Centers for Disease Control and Prevention, and other national public health organizations recommend that pregnant women be vaccinated at any stage during pregnancy and be given high priority for influenza vaccination25.There is currently no influenza vaccine approved by regulators and recommended in any country for use in infants younger than 6 months old, even if they have high-risk conditions for which influenza vaccination is recommended among older children. However, infants can be protected from influenza illness in the first few months of life by maternal antibodies transferred via the placenta during pregnancy and possibly through breastmilk postpartumThis review focuses on recent advances in the prevention of influenza illness in young infants (defined as less than 6 months of age) through vaccination during pregnancy. We also give a brief overview of the influenza viruses and epidemiology of the disease in this age group.26. Influenza A viruses are further divided into subtypes according to the antigenic properties of the surface glycoproteins hemagglutinin and neuraminidase. Eighteen antigenically different hemagglutinins (H1–18) and eleven different neuraminidases (N1–11) have been identified and their combination designates the virus subtype. Currently, H1 and H3 subtypes of influenza A are endemic in humans. Circulating influenza B viruses are classified into two groups: Yamagata-like or Victoria-like lineages27. Influenza A and B viruses are responsible for seasonal epidemics, and current vaccines are designed to target these viruses. Influenza type C viruses are detected much less frequently and cause mild infections, which do not present significant public health concerns. Influenza types differ in the range of animal hosts that they can infect: humans are the only known reservoir of influenza B and C, whereas influenza A is also found in other animals28. Given the multiple subtypes, higher mutation rates, and diverse hosts, influenza A poses the greatest pandemic threat. People are susceptible to influenza throughout their lives because of the ability of the virus to continually mutate by antigenic drift and antigenic shift (only influenza A viruses) mechanisms29.Influenza is caused by influenza viruses that circulate worldwide and that can be spread from person to person through airborne droplets or contact. Influenza viruses belong to the orthomyxoviridae family and have a segmented, negative-sense, single-stranded RNA genome with helical symmetry and different sizes of ribonucleoproteins. The influenza virus genus is divided into three types—A, B, and C—as defined by the antigenicity of the nucleoproteins and matrix proteins in the viral coreInfluenza infection attack rates and disease severity vary considerably from season to season and across world regions. In temperate countries, influenza viruses typically circulate at higher levels during colder winter months; in many tropical and subtropical regions, influenza occurs throughout the year.30. But influenza can cause severe illness or death, and infants are especially vulnerable to serious influenza complications31. Infants younger than 6 months old have the highest burden of childhood complications and death associated with influenza32. In severe pediatric cases, pneumonia, acute respiratory distress syndrome, secondary bacterial infection, febrile seizures, and neurologic complications such as encephalopathy and encephalitis can occur34. Influenza infection has also been associated with apnea in neonates35. However, in neonates and young children, non-febrile or non-respiratory manifestations of influenza infection (or both) are common37. The presentation of unspecific clinical signs renders surveillance difficult; thus, the real burden of influenza infections among the younger population is challenging to estimate. Another challenge to truly describing the overall burden of influenza-related severe disease is that severe complications from influenza virus infection, such as pneumonia, may occur days after the primary viral infection, when current diagnostics are less sensitive to detect low viral load by the time of hospitalization and testing38. Hence, the estimated rates of laboratory-confirmed influenza are likely to be an underestimation of the true burden of influenza disease39.The majority of influenza virus infections are self-limited, and the common symptoms are fever, chills, sore throat, myalgia, headache, coughing, and general discomfort. Most people recover within a week without requiring medical attention40. Data are more sparse from low- to middle-income countries (LMICs), but a recent systematic analysis on the burden of influenza in pediatric respiratory hospitalizations worldwide estimated that influenza causes approximately 870,000 hospitalizations per year in children younger than 5 years old , including 374,000 hospitalizations per year in infants younger than 1 year old , 228,000 of which occur in infants younger than 6 months old1. Furthermore, laboratory-confirmed influenza-associated hospitalization rates were more than three times higher in LMICs than in high-income countries1. In a previous population-based study in the USA during the 2002–2003 and 2003–2004 influenza seasons, the average annual influenza-associated hospitalization rate among infants younger than 6 months old was 450/100,000 infants compared with 90/100,000 among children 6–23 months old and 30/100,000 in the 24–59-month age group7. In a recent update of the influenza activity in the USA during the 2016–2017 influenza season, 18,184 laboratory-confirmed influenza-associated hospitalizations were reported, and the cumulative incidence among children younger than 5 years old was 44/100,000 children41.In the USA, during some winters, up to 10% of all infants are brought in for medical care for influenza-associated illness, including hospitalization7.Although influenza-associated hospitalizations are important, outpatient visits are far more frequent in all age groups. In infants, influenza infection tends to be more severe and more often requires hospitalization compared with older patients. Annual influenza-attributable outpatient visit rates in the USA in comparable age groups were approximately 10-, 100-, and 250-fold higher than hospitalization rates for children younger than 6 months, 6–23 months of age, and 24–59 months of age, respectively, in 2002–200442. Furthermore, it has been estimated that, in 2008, 28,000–111,500 deaths in children younger than 5 years old were due to influenza-associated acute lower respiratory infections, 99% of which occurred in LMICs43. No global mortality estimates, specifically for the subgroup younger than 6 months old, are available, but a study from the USA reported 0.88 deaths associated with laboratory-confirmed influenza per 100,000 infants younger than 6 months old in 2003–200432. Moreover, since 2004, when influenza-associated pediatric mortality became a notifiable condition in the USA, the total number of influenza-associated pediatric deaths per season has ranged from 37 to 171, excluding during the 2009 H1N1 pandemic (358 pediatric deaths were reported from April 2009 to October 2010)41.Global pediatric mortality estimates suggest that the proportion of influenza-associated deaths is highest among those younger than 1 year of age and that 2.8% of all deaths in this age group worldwide are caused by influenza44. Nevertheless, the immunogenicity of IIV, based on the induction of hemagglutinin antibodies, is generally similar in pregnant and non-pregnant women46.Immunological and physiological changes that occur during pregnancy to allow the allograft fetus to survive may affect the immune responses to vaccines and to infection47. This vertical antibody transfer is restricted to immunoglobulin G (IgG), and different IgG subclasses are transported with differing efficiency: IgG1 is the most efficiently transported and IgG2 is the least48. IIV during pregnancy boosts the maternal antibody levels and increases the number of antibodies transferred to the fetus49. Because of the theoretical risk to the fetus when the mother receives a live virus vaccine, live attenuated influenza vaccines are not recommended in pregnancy23. The passage of IgGs from the circulation of the mother to the fetus is a selective, cumulative, intracellular process mediated by the neonatal Fc receptor (FcRn) and probably other receptors still to be identified in the syncytiotrophoblast cells in the chorionic villi and subsequent release into the fetal circulation51.Maternal antibodies against several antigens, from natural infections or vaccination, are selectively transported across the placenta to the fetal circulation52; therefore, antibody concentrations are generally lower in premature than in full-term newborns54. Nevertheless, a study in Switzerland has shown that receipt of IIV at any time during the second and third trimester of pregnancy, but at least 2 weeks before delivery, increased the influenza-specific hemagglutinin antibodies in the newborns55. Similarly, a large IIV clinical trial in pregnant women in South Africa showed that higher transplacental antibody transfer was associated with longer periods of time between vaccination and delivery53. Although the transfer of antibodies is highest later in pregnancy, these results suggest a cumulative transfer and consequently that pregnant women should be vaccinated as soon as IIV is available at any time during pregnancy, not only to protect themselves as early as possible during the influenza season but also to increase the level of antibodies transferred to the fetus.The timing of vaccination during pregnancy influences the quantity of antibodies transferred to the fetus. Transplacental transfer of maternal antibodies begins during the second pregnancy trimester (around 17 weeks of gestation) and peaks towards the end of pregnancy when the expression of FcRn increases55. Owing to the active transport process, fetal hemagglutinin antibody concentrations can equal that of the mother and in some cases exceed maternal levels at term. A wide range of ratios of antibodies in infant at birth to mother at delivery have been reported after influenza vaccination during pregnancy57. Studies that evaluated the immunogenicity of inactivated monovalent pandemic H1N1 influenza vaccines in pregnant women57 normally detected higher newborn–to–maternal ratios of hemagglutinin antibody (1.4 to 2.9) compared with the trials that used trivalent vaccines, where ratios of hemagglutinin antibodies for the different influenza vaccine antigens ranged from 0.7 to 0.8 in the South African trial19 and from 0.8 to 1.1 in a trial from Bangladesh49.As shown in the Swiss study and previous studies, vaccination during pregnancy results in a detectable rise in the infant’s antibody levels to the vaccine antigens starting approximately 2 weeks after vaccination22, South Africa19, Mali21, and Nepal20 have demonstrated the efficacy of seasonal IIV vaccination during pregnancy in preventing laboratory-confirmed influenza in infants younger than 6 months old. In the first trial, conducted in Bangladesh from 2004 through 2005, 340 pregnant women received either pneumococcal polysaccharide vaccine or IIV during their third trimester. In that study, vaccine efficacy against laboratory-confirmed influenza in the infants was 63% ; in addition, there was a significant reduction in respiratory illnesses with fever in the infants, and vaccine efficacy was 29% 22. The South African trial included 2,116 human immunodeficiency virus (HIV)-uninfected pregnant women in the second or third trimester who were randomly assigned to IIV or placebo in 2011 or 2012. During the total follow-up period (until the infants reached 24 weeks of age), vaccine efficacy against laboratory-confirmed influenza in the infants was 49% 19. In Mali, 4,193 third-trimester pregnant women were randomly assigned to receive IIV or quadrivalent meningococcal vaccine from 2011 to 2013. During the entire study period, an overall vaccine efficacy of 33%  was demonstrated in infants younger than 6 months old21. The placebo randomized controlled trial in Nepal enrolled 3,693 pregnant women (17–34 weeks’ gestation) from 2011 through 2013, and infant vaccine efficacy was 30% 20. In a recent meta-analysis of the four trials, we calculated that the pooled efficacy of maternal IIV vaccination in preventing laboratory-confirmed influenza in infants younger than 6 months old was 36% 58.Four randomized controlled trials from Bangladesh60 and one from England61—evaluated the effect of IIV administered during pregnancy in preventing medically attended laboratory-confirmed influenza in infants younger than 6 months old. These studies reported a significant protective effect that was generally higher than reported in the clinical trials (71% to 41% reduction in the risk of laboratory-confirmed influenza for infants born to vaccinated women). The pooled effect of all clinical trials and observational studies was 48%  against influenza-confirmed infection among infants whose mothers were vaccinated during pregnancy58.Moreover, three observational studies—two from the USA63. Although there are a number of challenges regarding observational studies, the pooled vaccine effectiveness of influenza vaccination during pregnancy in preventing infant laboratory-confirmed influenza hospitalizations was 72% 58. The four randomized controlled trials performed to date were not designed to have individual power to detect an effect of maternal vaccination on hospitalizations for laboratory-confirmed influenza. However, in apost hoc analysis of the South African trial, maternal vaccination was associated with a 57%  reduction in all-cause acute lower respiratory tract infection (LRTI) among infants younger than 3 months old. Notably, this observation was independent of identifying influenza virus among the hospitalized cases, suggesting that preventing influenza infection may prevent subsequent LRTI in young infants. The negative polymerase chain reaction (PCR) results for influenza infection among these LRTI hospitalized cases may be partly explained by inadequate sample or imperfect test sensitivity. At least in adults, it has been shown that serologic assays demonstrated higher seropositivity for influenza than molecular testing, suggesting higher exposure than when looking at PCR-confirmed illness only64. It is also likely that exposure to the influenza virus initiated a causal chain of events leading to hospitalization for LRTI, even after virus shedding had ceased. Influenza virus infection could have increased the susceptibility to new bacterial nasopharyngeal acquisition, as well as increased the density of existing colonizing bacteria, with disease from these bacteria manifesting only a few weeks after virus clearance67; this is supported by epidemiological studies during the influenza epidemics and animal challenge models that demonstrated that influenza virus infection can enhance the susceptibility to infection with bacteria69.As mentioned above, outpatient visits are the most frequent medically attended events associated with influenza infection. But to measure the impact of influenza vaccination during pregnancy on hospitalizations that could be precipitated by influenza infection is of crucial importance. Four observational studies reported on the impact of maternal vaccination on laboratory-confirmed influenza hospitalizations in infants53 and Bangladesh49 for the different influenza-specific hemagglutinin antibodies in infants whose mothers received influenza vaccine during pregnancy. However, in HIV-uninfected women vaccinated during pregnancy, half-lives of the antibodies were about 100 days53. The effect of the decay in antibodies in infants was evident from the highest vaccine efficacy observed during the first 8 weeks of life in the South African trial (86% in infants younger than 8 weeks old versus 49% in infants younger than 6 months old)70 and the first 4 months of life in Mali (68% in infants younger than 4 months old versus 33% in infants younger than 6 months old)21.The duration of passive protection in the infant conferred by vaccination during pregnancy depends on the levels of antibodies achieved by vaccination, which are contingent on the efficiency of the transport across the placenta and how quickly the passively acquired antibodies wane. Half-lives of 42–50 days have been described in South AfricaIt has been postulated that the main mechanism of infant protection against laboratory-confirmed influenza infection provided by maternal vaccination is via the IgG antibodies that cross the placenta; however, the overall effect of protection is further confounded by the possible benefits of breastfeeding and reduced risk of exposure to the influenza virus from vaccinated mothers.71. In the same study, exclusive breastfeeding was associated with a decrease in the number of episodes of respiratory illness with fever in infants of mothers who received influenza vaccine during pregnancy.Besides the serum antibodies received via the placenta, protection might be provided by antibodies in the breastmilk of vaccinated mothers. This route of protection might be especially important for prematurely born neonates who had limited transplacental transfer of antibodies. However, immune responses in breastmilk after maternal vaccination have been less studied. In the trial in Bangladesh, breastmilk samples were obtained and specific IgA antibodies to H1N1 were significantly higher in IIV recipients than in mothers who received the pneumococcal vaccine for at least 6 months postpartum73. In South Africa during 2011, a smaller immunogenicity trial was performed in 194 HIV-infected pregnant women. Women were randomly assigned to receive IIV or placebo, and their infants were followed for laboratory-confirmed influenza until 6 months of age19. Before vaccination and 1 month post-vaccination, HIV-infected compared with HIV-uninfected pregnant women had lower levels of influenza-specific hemagglutinin antibodies and a decreased likelihood of seroconversion53. The transplacental antibody transfer was similar in the HIV-infected and HIV-uninfected cohorts for two of the three vaccine strains, but owing to the lower antibody levels post-vaccination among the HIV-infected women, their newborns had lower antibodies at birth than those born to HIV-uninfected women53. The study in HIV-infected women was not powered to detect vaccine efficacy in the HIV-exposed infants, and a similar influenza attack rate was detected in infants born to mothers who received IIV during pregnancy (5%) and those born to placebo recipients . However, these rates were higher than those detected in HIV-unexposed infants (1.6% in the IIV group versus 3.6% in the placebo group)19. To date, no other study has explored the benefit of maternal influenza vaccination in HIV-exposed infants in protection against laboratory-confirmed influenza.Infants born to HIV-infected mothers, even if themselves not HIV infected , have an increased risk of hospitalization and death from respiratory virus-associated LRTI, including influenza virus74. The different clinical trials on maternal influenza vaccination also reported rates of adverse events balanced between IIV and control groups. Recent systematic reviews of vaccine safety studies support the conclusions that there is no increased risk in the evaluated adverse outcomes in the mother, the fetus, and the newborn associated with influenza vaccination during pregnancy78. Most of the data, however, were obtained from studies with vaccination in the second and third trimesters. Pharmacovigilance programs need to continue monitoring the safety of maternal vaccination at any stage during pregnancy and, if possible, the impact of vaccination on the long-term development of the children.The WHO Global Advisory Committee on Vaccine Safety, in a safety review of the available evidence up until May 2013 of IIV during pregnancy, found no evidence of adverse pregnancy outcomes from vaccination79. This is the only antiviral approved for the treatment of influenza in infants but is not indicated for prevention in those younger than 1 year of age, although it can be used prophylactically in children older than 1 year of age at high risk, including those in close contact with individuals with known or suspected influenza infection80.In December 2012, the US Food and Drug Administration expanded the use of the antiviral oseltamivir phosphate to include infants 2 weeks of age and older for the treatment of uncomplicated influenza21) and young infants against influenza infection, this strategy should be used as the first line of protection. Nonetheless, there are still some considerations and open questions for future research in this field. These include the need for more immunogenic influenza vaccines for pregnant women to increase the concentration of the antibodies transferred transplacentally, which would last for a longer period in the infants. Infant passive protection beyond the first 2–4 months of life is desirable, as only after 6 months of age are infants eligible to receive influenza vaccine. More immunogenic vaccines could probably be achieved with higher antigen concentrations or the use of adjuvants. During the 2009 H1N1 pandemic, newer formulations of inactivated antigens administered with adjuvants were found to enhance the immune responses compared with non-adjuvanted vaccines85. Based on the immunogenicity data from the two South African trials, despite vaccine efficacy observed in HIV-infected mothers , alternate strategies to protect the HIV-exposed infants need to be considered19. Whilst vaccine-induced cell-mediated immunity might play a role in adults, protection in the infants will be mediated only by the presence of antibodies; hence, again, higher antibody concentrations need to be elicited in the women to prevent disease in their HIV-exposed infants.Since influenza vaccination during pregnancy was demonstrated to confer some protection to both mothers (not discussed in this reviewThe development of universal vaccines containing common antigens that could provide protection against different virus strains, reducing the need for annual vaccine update, and hopefully provide protection across multiple pregnancies is also being explored.The role of breastmilk antibodies in protection against influenza illness in infants also needs further elucidation.86 could help demonstrate any causal relationship between maternal infection during pregnancy and offspring’s disease outcome.Furthermore, evidence regarding an increased susceptibility or severe disease outcome in young infants born to influenza virus-infected mothers is still to be shown. Animal models such as a murine pregnancy model which mimics key clinical findings of the 2009 H1N1 influenza pandemic70.The paucity of high-quality data on the effect of vaccination during pregnancy against hospitalizations associated with laboratory-confirmed influenza in infants is still a limitation for truly estimating the effect size of this intervention on more severe outcomes. Large prospective multi-season studies with long-term follow-up powered to address this endpoint should be performed. Further research is also needed to better define the burden of influenza in young children, especially those presenting with non-respiratory symptoms or those who might have cleared the virus at the time of laboratory testing, using vaccine probe as a strategy to delineate this, as done in the South African trialCI, confidence interval; FcRn, neonatal Fc receptor; HIV, human immunodeficiency virus; IgG, immunoglobulin G; IIV, inactivated influenza vaccine; LMIC, low- to middle-income country; LRTI, lower respiratory tract infection; PCR, polymerase chain reaction; WHO, World Health Organization.


Although the vast majority of biological control agents is generally regarded as safe for humans and environment, the increased exposure of agriculture workers, and consumer population to fungal substances may affect the immune system. Those compounds may be associated with both intense stimulation, resulting in IgE-mediated allergy and immune downmodulation induced by molecules such as cyclosporin A and mycotoxins. This review discusses the potential effects of biocontrol fungal components on human immune responses, possibly associated to infectious, inflammatory diseases, and defective defenses. Phytophtora infestans a potato pathogen caused the Irish famine and diaspora in the XIX century , B. bassiana  by inducible nitric oxide synthase (iNOS) and reactive oxygen species (ROS) by neutrophils. In addition, both cell types display decreased expression of Clec7a gene that codes the Dectin-1 receptor, Toll Like Receptor 2 (Tlr2), and Toll Like Receptor 4 (Tlr4). Hence, the in vitro and in vivo experiments carried out with T. stromaticum suggested a possible negative modulation mainly of the cell components of the murine innate immune system.In contrast to immune response exacerbation due to stimulation of IgE production by common fungal allergens, a few studies demonstrated that biocontrol agents can impair immune system homeostasis through negative modulation. Mice exposed to intranasal Cylindrocapon lucidum, Trichoderma polysporum currently identified as Tolypocladium inflatum, Fusarium oxysporum, and T. harzianun fungi produce cyclosporin A (CsA)  make up the group of secondary metabolites named non-ribosomal peptides (NRPs) and, the success of Trichoderma virens . Both J774 and THP1 incubated with exogenous gliotoxin, display significantly reduced uptake of conidia of the three strains, indicating that the gliotoxin produced by A. fumigatus inhibits phagocytosis by macrophages (Jia et al., Although there is little evidence of the involvement of gliotoxin in human disease, exposure to this toxin appears to occur during infections by pathogenic fungi such as This gliotoxin inhibits neutrophil ability to produce bona fide knowledge regarding symptoms and doses that cause susceptibility in individuals and little is known about the presence of this toxin in bioaerosols. Studies determined a total of 0.22 microgram of gliotoxin in extract of 6.2 × 108 spores from Aspergillus fumigatus mechanically disintegrated (Schulz et al., Trichoderma including T. viride and T. virens (Brian and Hemming, The detection and relevance of gliotoxin from biocontrol fungi to human health, particularly for occupationally exposed individuals were scarcely studied. There is no in-depth, Candida albicans reverses or impairs the activation of human monocytes cultured with endotoxin. This β-glucan effect is associated to the suppressed production of the type 1 cytokines IL-2 and IFN-γ by cultured human PBMC (Nakagawa et al., Cell wall components such as chitin and β-glucan were identified in biocontrol fungi spores and are extensively studied during biocontrol-pathogen-plant interaction. These carbohydrate polymers may induce modulatory activity affecting the production of both pro-inflammatory and anti-inflammatory cytokines (Sorrell and Chen, As the structure of the fungal cell wall and the PAMPs exposed at the cell surface are genus-, species- and morphotype-dependent (Brodaczewska et al., All authors listed, have made substantial, direct and intellectual contribution to the work, and approved it for publication.This article was funded by a grant from Universidade Estadual de Santa Cruz—Brazil.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.


MYC sustains non-stop proliferation by altering metabolic machinery to support growth of cell mass. As part of the metabolic transformation MYC promotes lipid, nucleotide and protein synthesis by hijacking citric acid cycle to serve biosynthetic processes, which simultaneously exhausts ATP production. This leads to the activation of cellular energy sensing protein, AMP-activated protein kinase (AMPK). Cells with normal growth control can stop cell proliferation machinery to replenish ATP reservoirs whereas MYC prevents such break by blocking the cell cycle exit. The relentless cell cycle activation, accompanied by sustained metabolic stress and AMPK activity, switches the energy-saving AMPK to pro-apoptotic AMPK. The AMPK-involving metabolic side of MYC apoptosis may provide novel avenues for therapeutic development. Here we first review the role of anabolic MYC and catabolic AMPK pathways in context of cancer and then discuss how the concomitant activity of both pathways in tumor cells may result in targetable synthetic lethal vulnerabilities. The classical view of oncogenic MYC expression being a cell cycle reprogrammer has recently broadened in the light of new genome-scale promoter and transcriptomic studies, which have exposed MYC's widespread transcriptional impact across the genome and especially on the genes orchestrating anabolic metabolism activation of cell cycle checkpoints and consequently, selective induction of apoptosis in transformed cells , which is an inhibitor of thymidylate synthase, or with methotrexate, an inhibitor of dihydrofolate reductase and folates, leads to depletion of deoxyribonucleotides and perturbed DNA synthesis, which amounts a lethal level metabolic stress to cancer cells  analyses combined with next-generation sequencing have indeed corroborated earlier findings by exposing plethora of MYC regulated genes with annotated functions in cell cycle regulation and DNA replication Figure . HoweverThe new data does not change our principal view on MYC. MYC is still a major driver of the cell cycle. However, it now appears that MYC drives a very sustainable program of cell proliferation by inducing sufficient production of biomass and biosynthetic building blocks for cell growth, which ensures that one cell division results in two about equal size of cells rather than two small cells.Proliferating cancer cells have fundamentally different metabolic status compared to differentiated, mainly resting adult cells; measurable changes encompass all domains of cellular metabolism, such as bioenergetics, biosynthesis and redox potential . We single out below three metabolic pathways, which are altered by MYC and which represent the metabolic phenotype of many types of cancer cells Figure .MYC enhances glucose uptake by upregulating glucose transporters GLUT1) , which is composed of the catalytic α-subunit and two regulatory subunits β and γ. AMPK has four adenine nucleotide-binding clefts of which two (sites 1 and 3) bind AMP, ADP, or ATP in a competative manner Hardie, . In unstAMPK activation coordinates number of metabolic signaling pathways with the general purpose of switching on ATP generating catabolic pathways, while simultaneously switching off ATP consuming biosynthetic pathways. Some of these pathways will be discussed in more detail below but the principal impacts of AMPK activation on the catabolic pathways include stimulation of glucose uptake, glycolysis, fatty acid uptake, fatty acid oxidation, mitochondrial biogenesis and autophagy. AMPK activates the main mitochondrial biogenesis inducer PGC-1α, which then activates sequence of events via NRF-1 and NRF-2 transcription factors leading to increased production of mitochondrial enzymes as well as transcription and replication of mitochondrial DNA  led to nuclear accumulation of p53, the activation of MYC in the same cells re-routed p53 to interact with BAK and BCL-XFrom these findings we formulated the hypothesis that non-transformed cells have the ability to deal with declining ATP levels because of AMPK-p53-mediated checkpoint control mechanism  positively regulates the activity of at least 14 AMPK related downstream kinases  exerts apoptotic effects in p53-deficient, but not in the wild type p53 xenografts  to the cells, suggesting that the anaplerotic flux of glutamine into the Krebs cycle is a critical survival mechanism  prepared the figures.This work was funded by the Academy of Finland, TEKES, and Finnish Cancer Organizations. HH and JA were funded by Integrative Life Sciences (ILS) doctoral program. HH was funded by Emil Aaltonen foundation, Inkeri and Mauri Vänskä Foundation and Biomedicum Helsinki foundation.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.


We present here a brief description of the path that cholesterol covers from its intestinal absorption to its effect exerted on some enzyme regulation. Some mechanisms underlying hypercholesterolemia onset and, in particular, the role and the regulation of 3-hydroxy 3-methylglutaryl Coenzyme A reductase (HMGR) during adult life and during aging, have been described. In addition some pharmacological interventions to control proper HMGR regulation and, in turn, cholesterol homeostasis maintenance will be introduced.


PGC-1α, SIRT1, and AMPK genes. Furthermore, the gut microbiota and its metabolites, such as short chain fatty acids and secondary bile acids, also contribute to host energy production, ROS modulation and inflammation in the gut by attenuating TNFα- mediated immune responses and inflammasomes such as NLRP3. On the other hand, mitochondria, particularly mitochondrial ROS production, have a crucial role in regulating the gut microbiota via modulating intestinal barrier function and mucosal immune responses. Recently, it has also been shown that genetic variants within the mitochondrial genome, could affect mitochondrial function and therefore the intestinal microbiota composition and activity. Diet is also known to dramatically modulate the composition of the gut microbiota. Therefore, studies targeting the gut microbiota can be useful for managing mitochondrial related ROS production, pro-inflammatory signals and metabolic limits in endurance athletes.Many physiological changes occur in response to endurance exercise in order to adapt to the increasing energy needs, mitochondria biogenesis, increased reactive oxygen species (ROS) production and acute inflammatory responses. Mitochondria are organelles within each cell that are crucial for ATP production and are also a major producer of ROS and reactive nitrogen species during intense exercise. Recent evidence shows there is a bidirectional interaction between mitochondria and microbiota. The gut microbiota have been shown to regulate key transcriptional co-activators, transcription factors and enzymes involved in mitochondrial biogenesis such as  Endurance exercise can be defined as cardiovascular exercise—such as running, cross-country skiing, cycling, aerobic exercise or swimming—that is performed for an extended period of time  tend to control mitochondrial activity in favor of infection and inflammation through the production of hydrogen sulfide (H2S) and nitrogen oxide (NO) , sample size, year of publication, publication status or follow-up; however, we only consulted articles published in English and did not include any doctorate thesis. Bibliographies of the identified reviews and original research publications were hand-selected for additional studies that may have been missed by the database searches. All articles were exported to the reference database Zotero. Due to the nature of this review, no request was performed for the ethics committee's approval.Full copies of citations coded as potentially relevant were obtained, and those meeting the inclusion criteria were read in detail and data extracted. One reviewer (AC) extracted information about the study aim, population and sample size, experimental design, and duration of follow-up, specie, individual characteristics, and changes in the gut microbiota composition, energy metabolism, redox activity and immune response and association or not with mitochondrial function during endurance exercise. The primary outcome was the crosstalk occurred between the gut microbiota and mitochondria in response to intense exercise that includes: the gut microbiota's regulation of key mediators in mitochondrial biogenesis  as well as exercise-induced oxidative stress and inflammation in the gut. Details were then checked by a second reviewer (NM). If eligibility could be determined, the full article was retrieved.The articles and extracted data were read and the findings organized by: (i) mitochondrial functions involved in energy production, ROS production and inflammation during endurance exercise; (ii) experimental studies about the possible crosstalk between mitochondrial function and the gut microbiota; (iii) experimental studies that demonstrated a possible link between mitochondrial functions and changes in the gut microbiota profiling in response to endurance exercise; (iv) experimental studies or reviews that showed a relationship between the roles the genetic variants in mitochondrion genome play in gut functions and microbiota profiling.A search conducted in January 2017 resulted in the following list of key terms combinations . A total of 77 experimental studies and 84 reviews met the inclusion criteria and were included in the review. Most of the articles were reviews or randomized controlled trials. Periods of data collection spanned from 1980 to 2017, proving data from humans and animals models .Mitochondria are dynamic organelles whose quantity and volume changes in response to cellular oxidative and metabolic demands. Although the mitochondrial genome is small, mitochondrial DNA encodes genes that might be essential for energy production, redox balance and inflammation regulation during endurance exercise. The human mitochondrial genome is a 16.6 kb circular DNA that encodes 13 peptides involved in OXPHOS, two ribosomal, and 22 transfer RNA that are crucial for intra-mitochondrial protein synthesis. Mitochondria functions are under dual genetic control of both the mitochondrial genome and the nuclear genome. It is known that more than 1,500 genes encoded by nuclear genome  , tumor suppressor p53, signal transducer and activator of transcription 3 (STAT3) and the estrogen receptors all control mitochondrial function  subunit II and COX unit IV , an enzyme also involved in mitochondrial biogenesis. AMPK is activated by cytokines and exercise primarily in response to changes in the AMP: ATP ratio , a redox sensitive energy sensor, can also affect mitochondrial biogenesis via PGC-1α deacetylation  also regulate mitochondrial functions by modifying energy production, ROS production, inflammatory responses and transcription factors involved in mitochondrial biogenesis. By definition, individual strains of a bacterial species can differ by up to 30% in terms of genetic sequence Zhao, . ConsideRickettsia   production of ROS and RONS, (ii) induction of the secretion of immune cells and enterochromaffin cells, (iii) modulation of gut functions, such as intestinal barrier function and appropriate mucosal immune response, all important for the maintenance of the mucus layer and biofilm where individual groups of bacteria grow, (iv) mitochondrial genetic variants and heteroplasmy Figure .2 max, which enables better oxygen uptake, OXPHOS and FAO in skeletal muscles  animals or specific pathogen-free (SPF) animals have shown that the SCFAs, such as N-butyrate and acetate, may affect mitochondrial energy metabolism through a vast range of transcription factors that directly or indirectly control mitochondrial functions. The types and amount of SCFAs produced by gut microorganisms depends on the composition of the gut microbiota, metabolic interactions between microbial species and the amount and type of the main dietary macro- and micronutrients ingested  to type I (oxidative), which are rich in mitochondria and stimulate FAO for ATP production  prevented insulin resistance by stimulating thermogenesis and fatty acid oxidation in skeletal muscle and brown adipose tissue mitochondria in part due to increased PPARγ gene expression resulting in decreased lipogenesis and increased AMP: ATP ratio. The increased AMP: ATP ratio can also activate AMPK in liver, adipose , also known as G-coupled receptor protein 43 (GRP43) and GRP41 respectively, that regulate glucose and fatty acid metabolism , through PPAR-α dependent pathways  and G-coupled membrane protein 5 (TGR5) , carbohydrate response element binding protein (ChREBP), and PPAR-α, which stimulates fatty acid uptake and oxidation  in the large intestines. H2S is an important mediator of many physiological and pathological processes. High amounts of H2S can inhibit a key component of the mitochondrial respiratory chain by penetrating cell membranes and inhibiting COX activity and energy production . It is clear then that the interaction between diet and exercise needs to be further studied in order to better assess the contributions of diet and microbial activities in mitochondria functions and athletic performance.Given the lack of studies in human endurance athletes, it's difficult to make precise dietary recommendations for endurance athletes in regards to how to optimize SCFA and bile acid metabolism for energy production. However, high animal protein consumption during resting days and training may negatively affect the gut microbiota of elite athletes  induced mitochondrial oxidative stress. This was confirmed by increased ROS production, which induced the inflammasome-NOD-like receptor family and pyrin domain containing 3 (NLRP3). Similarly, we have recently demonstrated in horses, which are considered to serve as an optimal in vivo model for characterizing the response to endurance exercise, that the elevated respiration rates during endurance exercise had led to the generation of more ROS than the antioxidant systems can scavenge  and NAD phosphate (NADP) . A review by Lobet et al.  experienced exercise-induced mitochondrial stress, which was confirmed by increased ROS production and NLRP3 expression.A key mechanism of inflammation is the activation of inflammasomes, which are large cytosolic protein complexes that activate caspase-1, which induce the inflammatory cytokines IL-1 and IL-18 and facilitates other inflammatory mediators that are crucial for the innate immune response. Mitochondria play a central role in the initiation of inflammasomes and other inflammatory pathways and as such integrate autophagy, cell death, and inflammation  concentration and the AMP: ATP ratio leading to energy synthesis in muscles. Another study by Lantier et al. , whereas others are only present in some copies of the mitochondrial genome (heteroplasmic mutation)  and Roseburia genera abundance (Clostridium cluster XIVa), which are highly oxygen-sensitive anaerobes and butyrate producers. Similarly, the non-synonymous polymorphism T14798C, which maps to cytochrome b gene, was strongly associated with differential abundance of Dialister in the vaginal posterior fornix  or disorders in the long-chain fatty acid oxidation in the mitochondrion  are more prone to bacterial infection than general population  also demonstrated that the HV haplogroup was associated with higher ROS production and mitochondrial oxidative damage compared to the JT haplogroup  is required.SIRT1 and the enzyme AMPK, which suppress a broad inflammatory response and mediate beneficial effects of exercise. Dampening inflammation and oxidative stress during endurance exercise would be an ideal approach to restricting blooms of pathobionts in the gut as well as their detrimental effects on mitochondrial functions. Although it remains a challenge to tone down inflammatory response through dietary treatments, maneuvering nutritional changes and oxidative stress might be a good approach to maintain a healthy gut microbiota and thereby maintain mitochondrial functions and host homeostasis. On the other hand, mitochondrial ROS production has a crucial role in the regulation of gut functions such as intestinal barrier integrity and mucosal immune responses, all of which are important for regulating the gut microbiota composition. Despite the diminutive size of the mitochondrial genome, mitochondrial DNA mutations are inherited and might affect not only tissue functions but also microbiota functions. Mutations in mitochondrial genes  or in the D- Loop region and oxidative stress also modulate gut microbiota composition and functions. Therefore, understanding the multiple molecular pathways that lead to mitochondrial DNA mutations accumulations is needed.Many lines of evidence suggest that mitochondria have a central role in energy production, ROS and RONS production and regulation of inflammasomes during endurance exercise. Endurance exercise induces systemic mitochondrial biogenesis, prevents mitochondrial DNA depletion and mutations, and increases mitochondrial oxidative and antioxidant capacity. However, overtraining and chronic stress promotes inflammation in the gastrointestinal tract of athletes which results in a plethora of stressors that favor the lipopolysaccharide translocation and the proliferation of pathobionts. We are still in the infancy of understanding the bidirectional crosstalk between the gut microbiota and mitochondria, but several studies shown that commensal gut microbiota molecules, such as N-butyrate, are essential for controlling mitochondrial oxidative stress and inflammatory responses, pathogen growth and adherence as well as in improving metabolism and energy expenditure during exercise. Furthermore, short chain fatty acids can induce key mediators in mitochondrial biogenesis through transcriptional co-activators such as PCG-1α, the redox sensitive energy sensor AC wrote the main text and both AC and NM designed the figures. NM provided critical feedback on content, design and revision of the manuscript. Both authors have edited and approved the final version of the 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. The reviewer MB and handling Editor declared their shared affiliation, and the handling Editor states that the process nevertheless met the standards of a fair and objective review.