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Although the role of RNA binding proteins (RBPs) in extracellular RNA (exRNA) biology is well established, their exRNA cargo and distribution across biofluids are largely unknown. To address this gap, we extend the exRNA Atlas resource by mapping exRNAs carried by extracellular RBPs (exRBPs). This map was developed through an integrative analysis of ENCODE enhanced crosslinking and immunoprecipitation (eCLIP) data (150 RBPs) and human exRNA profiles (6,930 samples). Computational analysis and experimental validation identified exRBPs in plasma, serum, saliva, urine, cerebrospinal fluid, and cell-culture-conditioned medium. exRBPs carry exRNA transcripts from small non-coding RNA biotypes, including microRNA (miRNA), piRNA, tRNA, small nuclear RNA (snRNA), small nucleolar RNA (snoRNA), Y RNA, and lncRNA, as well as protein-coding mRNA fragments. Computational deconvolution of exRBP RNA cargo reveals associations of exRBPs with extracellular vesicles, lipoproteins, and ribonucleoproteins across human biofluids. Overall, we mapped the distribution of exRBPs across human biofluids, presenting a resource for the community.

Sertoli cells are somatic cells that are in close contact with germ cells in the mammalian testes. They have multiple functions and fulfill key roles for the development and proper maturation of spermatogenic cells into functional spermatozoa. One of their most important properties is to release trophic factors and supply nutrients to germ cells. But they are also involved in the regulation of the immune system in testis, and provide an immunologically privileged environment for developing germ cells. Because they are so essential for reproductive cells, their alterations can have detrimental consequences for fertility. Many environmental factors and exposures such as high caloric diet, toxins, and pollutants are thought to compromise Sertoli cells physiology. This review describes the discovery of Sertoli cells and the methods used for their study, summarizes their major properties and functions, and describes their dysfunctions in pathologies, particularly associated with environmental stressors., Andrology, 11 (5), ISSN:2047-2919, ISSN:2047-2927

Sperm RNA can be modified by environmental factors and has been implicated in communicating signals about changes in a father's environment to the offspring. The small RNA composition of sperm could be changed during its final stage of maturation in the epididymis by extracellular vesicles (EVs) released by epididymal cells. We studied the effect of exposure to stress in early postnatal life on the transcriptome of epididymal EVs using a mouse model of transgenerational transmission. We found that the small RNA signature of epididymal EVs, particularly miRNAs, is altered in adult males exposed to postnatal stress. In some cases, these miRNA changes correlate with differences in the expression of their target genes in sperm and zygotes generated from that sperm. These results suggest that stressful experiences in early life can have persistent biological effects on the male reproductive tract that may in part be responsible for the transmission of the effects of exposure to the offspring.

Sertoli cells are somatic cells in testes essential for spermatogenesis, as they support the development, maturation, and differentiation of germ cells. Sertoli cells are metabolically highly active and physiologically regulated by external signals, particularly factors in the blood stream. In disease conditions, circulating pathological signals may affect Sertoli cells and consequentially, alter germ cells and fertility. While the effects of stress on reproductive cells have been well studied, how Sertoli cells respond to stress remains poorly characterized. Therefore, we used a mouse model of early postnatal stress to assess the effects of stress on Sertoli cells. We developed an improved enrichment strategy based on intracellular stainings and obtained enriched preparations of adult Sertoli cells from exposed males. We show that adult Sertoli cells have impaired electron transport chain (ETC) pathways and that several components of ETC complexes I, III, and IV are persistently affected. We identify the circulation as a potential mediator of the effects of stress, since treatment of primary Sertoli cells with serum from stressed males induces similar ETC alterations. These results newly highlight Sertoli cells as cellular targets of early life stress, and suggest that they may contribute to the negative effects of stress on fertility.HighlightsWe present an improved method to obtain enriched preparations of Sertoli cells from adult mouse testis for molecular analysesSertoli cells from adult males exposed to stress during early postnatal life have altered electron transport chain (ETC) expression, suggesting persistent effects of early life stress on Sertoli cells physiologySerum from adult males exposed to early postnatal stress reproduces ETC gene dysregulation in cultured Sertoli cells.Graphical abstract

Life experiences and environmental conditions in childhood can change the physiology and behaviour of exposed individuals and in some cases, of their offspring. In rodent models, stress/trauma, poor diet and endocrine disruptors in a parent have been shown to cause phenotypes in the direct progeny, suggesting intergenerational inheritance. A few models also examined transmission to further offspring and suggested transgenerational inheritance, but such multi-generations inheritance is not well characterized. Our previous work in a mouse model of early postnatal stress showed that behaviour and metabolism are altered in the offspring of exposed males up to the 4th generation in the patriline and up to the 2nd generation in the matriline. The present study examined if in the patriline, symptoms can be transmitted beyond the 4th generation. Analyses of the 5th and 6th generation of mice revealed that altered risk-taking and glucose regulation caused by postnatal stress are still manifested in the 5th generation but are attenuated in the 6th generation. Some of the symptoms are expressed in both males and females, but some are sex-dependent and sometimes opposite. These results indicate that postnatal trauma can affect behaviour and metabolism over many generations, suggesting epigenetic mechanisms of transmission.

Childhood trauma (CT) can have persistent effects on the brain and is one of the major risk factors for neuropsychiatric diseases in adulthood. Recent advances in the field of epigenetics suggest that epigenetic factors such as DNA methylation and histone modifications, as well as regulatory processes involving non-coding RNA are associated with the long-term sequelae of CT. This narrative review summarizes current knowledge on the epigenetic basis of CT and describes studies in animal models and human subjects examining how the epigenome and transcriptome are modified by CT in the brain. It discusses psychological and pharmacological interventions that can counteract epigenetic changes induced by CT and the need to establish longitudinal assessment after CT for developing more effective diagnostics and treatment strategies based on epigenetic targets. ISSN:0149-7634 ISSN:1873-7528

Sperm RNA can be modified by environmental factors and has been implicated in communicating signals about changes in a father’s environment to the offspring. The RNA composition of sperm is influenced during its final stage of maturation in the epididymis by extracellular vesicles released by epididymal cells. We studied the effect of exposure to stress in postnatal life on the transcriptome of epididymal extracellular vesicles using a mouse model of transgenerational transmission. We found that the small RNA signature of epididymal extracellular vesicles, particularly miRNAs, is altered in adult males exposed to postnatal stress. miRNAs changes correlate with differences in the expression of their target genes in sperm and zygotes generated from that sperm. These results suggest that stressful experiences in early life can have persistent biological effects on the male reproductive tract that may in part be responsible for the transmission of the effects of exposure to the offspring.Summary SentencemiRNA cargo of extracellular vesicles in cauda epididymis is changed by paternal exposure to early life stress, which correlates with differences in the expression of their target genes in sperm and zygotes generated from that sperm

Nature Communications, 12 (1), ISSN:2041-1723

Depression, cardiovascular diseases and diabetes are among the major non-communicable diseases, leading to significant disability and mortality worldwide. These diseases may share environmental and genetic determinants associated with multimorbid patterns. Stressful early-life events are among the primary factors associated with the development of mental and physical diseases. However, possible causative mechanisms linking early life stress (ELS) with psycho-cardio-metabolic (PCM) multi-morbidity are not well understood. This prevents a full understanding of causal pathways towards the shared risk of these diseases and the development of coordinated preventive and therapeutic interventions., This work is supported by the European Union’s Horizon 2020 research and innovation programme (grant n ̊ 848158).

Die Frage nach der Vererbbarkeit von epigenetischen Veränderungen, also von Änderungen nicht der Gene selbst, sondern ihrer Aktivität, wird schon lange und sehr kontrovers diskutiert. In ihrem Beitrag stellen Ali Jawaid und Isabelle M. Mansuy den gegenwärtigen Stand der Forschung zu generationsübergreifenden Auswirkungen von Traumata dar und diskutieren deren Bedeutung für Individuen und Gesellschaft. Traumata definieren sie als überwältigenden Stress, der die physische und psychische Gesundheit von Betroffenen dauerhaft schädigen und bspw. zu einer erhöhten Krankheitsanfälligkeit und posttraumatischen Belastungsstörungen führen könne. Die biologische Basis der Vererbung der Folgen psychischer Traumata liegt dem Autorenteam zufolge in der Übertragung epigenetischer Veränderungen auf die Fortpflanzungsorgane und die Keimbahn durch die traumabedingte Aktivierung bestimmter Signalwege. Ali Jawaid und Isabelle M. Mansuy fassen ihren Beitrag folgendermaßen zusammen: „Die Vorstellung, dass psychologische Traumata zu Effekten führen, die potenziell vererbbar sind, ist von großer Bedeutung für die Gesellschaft, wenn man bedenkt, wie viele Individuen durch gegenwärtige und jüngste menschliche Konflikte traumatisiert wurden. Dieses Kapitel diskutiert das Konzept der epigenetischen Vererbung im Zusammenhang mit Merkmalen, die aus einer solchen Traumaexposition resultieren, sowie deren Auswirkungen auf das Leben eines Individuums und auf die Gesellschaft. Es gibt einen Überblick über Studien an Tieren und Menschen zur inter- und transgenerationalen Weitergabe der Auswirkungen psychologischer Traumaexpositionen, indem es die Frage behandelt, wie Traumaexposition und damit verbundene emotionale und kognitive Störungen Spuren in der Keimbahn hinterlassen können. Auch die Frage nach ‚Gelegenheitsfenstern‘ in verschiedenen Lebensabschnitten, von der Kindheit bis zum Erwachsenenalter, in denen die Vererbung von Traumafolgen verhindert werden kann, wird diskutiert. Insbesondere arbeitet das Kapitel die Implikationen der Forschung über die Vererbung von Traumafolgen im Zusammenhang mit politischen und ethnischen Konflikten heraus. Dabei geht es auch darum, was Menschen, die langfristig Frieden sichern wollen (‚peace builder‘), aus dem Gebiet der epigenetischen Vererbung lernen können und wie sie mit Wissenschaftler*innen zusammenarbeiten können, um Strategien und politische Entscheidungen mit biologischen Erkenntnissen zu bereichern und den Frieden zu fördern“ (S. 278–279).

Environmental factors can change phenotypes in exposed individuals and offspring and involve the germline, likely via biological signals in the periphery that communicate with germ cells. Here, using a mouse model of paternal exposure to traumatic stress, we identify circulating factors involving peroxisome proliferator‐activated receptor (PPAR) pathways in the effects of exposure to the germline. We show that exposure alters metabolic functions and pathways, particularly lipid‐derived metabolites, in exposed fathers and their offspring. We collected data in a human cohort exposed to childhood trauma and observed similar metabolic alterations in circulation, suggesting conserved effects. Chronic injection of serum from trauma‐exposed males into controls recapitulates metabolic phenotypes in the offspring. We identify lipid‐activated nuclear receptors PPARs as potential mediators of the effects from father to offspring. Pharmacological PPAR activation in vivo reproduces metabolic dysfunctions in the offspring and grand‐offspring of injected males and affects the sperm transcriptome in fathers and sons. In germ‐like cells in vitro, both serum and PPAR agonist induce PPAR activation. Together, these results highlight the role of circulating factors as potential communication vectors between the periphery and the germline., The EMBO Journal, 39 (23), ISSN:0261-4189, ISSN:1460-2075

In mammals, spermatogonial cells exit quiescence immediately after birth and initiate a life-long equilibrium between proliferation and differentiation for the production of spermatogenic cells and functional sperm. Although it is generally accepted that the transcriptome of spermatogonial cells is different in postnatal life and adulthood, it is not known if the genome landscape at the chromatin level is also different across age. We characterized the transcriptome and chromatin landscape of spermatogonial cells by RNA-seq and ATAC-seq using enriched populations at different postnatal stages and in adulthood, and established a comprehensive multiparametric profiling building on published epigenetic datasets. Our results validate previously described changes in gene expression between postnatal and adult stages, and reveal novel transcriptomic transitions. We show that extensive chromatin remodeling takes place in adult spermatogonial cells that is accompanied by distinct transcription factor dynamics and histone modifications. The data identify chromatin and transcription factor dynamics at common repeat elements in postnatal and adult spermatogonia. Overall, our results provide new knowledge about the transcriptional and epigenetic landscape of spermatogonial cells across postnatal stages until adulthood, and provide a valuable resource for germ cell studies.

The possibility that parental life experiences and environmental exposures influence mental and physical health across generations is an important concept in biology and medicine. Evidence from animal models has established the existence of a non-genetic mode of inheritance. This form of heredity involves transmission of the effects of parental exposure to the offspring through epigenetic changes in the germline. Studying the mechanisms of epigenetic inheritance in humans is challenging because it is difficult to obtain multigeneration cohorts, to collect reproductive cells in exposed parents, and to exclude psychosocial and cultural confounders. Nonetheless, epidemiological studies in humans exposed to famine, stress/trauma, or toxicants have provided evidence that parental exposure can impact the health of descendants, in some cases, across several generations. A few studies have also started to reveal epigenetic changes in the periphery and sperm after certain exposures. This article reviews these studies and evaluates the current evidence for the potential contribution of epigenetic factors to heredity in humans. The challenges and limitations of this fundamental biological process, its implications, and its societal relevance are also discussed.

Psychiatric diseases have a strong heritable component known to not be restricted to DNA sequence-based genetic inheritance alone but to also involve epigenetic factors in germ cells. Initial evidence suggested that sperm RNA is causally linked to the transmission of symptoms induced by traumatic experiences. Here, we show that alterations in long RNA in sperm contribute to the inheritance of specific trauma symptoms. Injection of long RNA fraction from sperm of males exposed to postnatal trauma recapitulates the effects on food intake, glucose response to insulin and risk-taking in adulthood whereas the small RNA fraction alters body weight and behavioural despair. Alterations in long RNA are maintained after fertilization, suggesting a direct link between sperm and embryo RNA., Molecular Psychiatry, 25, ISSN:1359-4184, ISSN:1476-5578

Prolonged periods of social isolation can have detrimental effects on the physiology and behavior of exposed individuals in humans and animal models. This involves complex molecular mechanisms across tissues in the body which remain partly identified. This review discusses the biology of social isolation and describes the acute and lasting effects of prolonged periods of social isolation with a focus on the molecular events leading to behavioral alterations. We highlight the role of epigenetic mechanisms and non-coding RNA in the control of gene expression as a response to social isolation, and the consequences for behavior. Considering the use of strict quarantine during epidemics, like currently with COVID-19, we provide a cautionary tale on the indiscriminate implementation of such form of social isolation and its potential damaging and lasting effects in mental health. ISSN:1664-8021

Traumatic experiences during childhood can persistently alter mental and physical health in humans and have been implicated in transmission of symptoms to the progeny in animal models. Molecular evidence from these models implicates epigenetic/non-genetic factors, such as microRNAs (miRNAs), in the expression of trauma-induced symptoms and their transmission to the offspring. To confirm these findings in humans, we assembled three cohorts of subjects exposed to childhood trauma and examined selected miRNAs linked to psychological and pathophysiological manifestations of childhood trauma. Children aged 7- 12 years (n = 72, control n = 30) exposed to paternal loss and maternal separation (PLMS) exhibited increase in two miRNAs, miR-16 and miR-375 in serum and reduced level of high density lipoproteins (HDL) compared to control children. Comparable miRNA changes were observed in serum of adult men aged 18-25 years (n = 13, control n = 17) who had been exposed to PLMS at a young age. Finally, the same miRNAs were altered in sperm of adult men aged 21-50 years (n = 23, control n = 35) exposed to two or more significant traumatic events in childhood, assessed retrospectively using the standardized childhood trauma questionnaire (CTQ). In vitro experiments show that regulation of these miRNA involves the HDL receptor SRB-1, suggesting a link between trauma-associated miRNAs and metabolic alterations., medRxiv

The concept of epigenetic inheritance proposes a new and unconventional way to think about heredity in health and disease, at the interface between genetics and the environment. Epigenetic inheritance is a form of biological inheritance not encoded in the DNA sequence itself but mediated by epigenetic factors. Because epigenetic factors can be modulated by the environment, they can relay this information to the genome and modify its activity consequentially. If epigenetic changes induced by environmental exposure are present in the germline and persist in germ cells during development until conception, they have the potential to transfer the traces of ancestral exposure to the progeny. This form of heredity relates to the extremely important question of nature versus nurture and how much of our own make-up is genetically or epigenetically determined, a question that remains largely unresolved. Because it questions the dominant dogma of genetics and brings a paradigm shift in sciences, it has to creating strong bridges between disciplines and provide solid causal evidence to be firmly established. The second edition of a conference fully dedicated to epigenetic inheritance was held in August 2019 in Zurich, Switzerland. This symposium titled 'Epigenetic inheritance: impact for biology and society' (http://www.epigenetic-inheritance-zurich.ethz.ch), gathered experts in the field of epigenetic inheritance to discuss the concept and pertinent findings, exchange views and expertise about models and methods, and address challenges raised by this new discipline. The symposium offered a mix of invited lectures and short talks selected from abstracts, poster sessions and a workshop 'Meet the experts: Q&A'. A tour of a local omics facility the Functional Genomics Center Zurich was also offered to interested participants. Additional comments and impressions were shared by attendees on Twitter #eisz19 during and after the symposium. This summary provides an overview of the different sessions and talks and describes the main findings presented., Environmental Epigenetics, 6 (1), ISSN:2058-5888

Summary: The hippocampal formation is a brain structure essential for higher-order cognitive functions. It has a complex anatomical organization and cellular composition, and hippocampal subregions have different properties and functional roles. In this study, we used SWATH-MS to determine whether the proteomes of hippocampus areas CA1 and CA3 can explain the commonalities or specificities of these subregions in basal conditions and after recognition memory. We show that the proteomes of areas CA1 and CA3 are largely different in basal conditions and that differential changes and dynamics in protein expression are induced in these areas after recognition of an object or object location. While changes are consistent across both recognition paradigms in area CA1, they are not in area CA3, suggesting distinct proteomic responses in areas CA1 and CA3 for memory formation. : How does the proteome differ in hippocampus areas CA1 and CA3? von Ziegler et al. identify the proteomes of areas CA1 and CA3 and characterize their dynamics during different recognition processes in adult mice. Keywords: hippocampus, areas CA1 and CA3, proteome, dynamics, object memory, object location memory, mass spectrometry, SWATH-MS, mice, bioinformatic tools

5-hydroxymethylation (5-hmC) is an epigenetic modification on DNA that results from the conversion of 5-methylcytosine by Ten-Eleven Translocation (TET) proteins. 5-hmC is widely present in the brain and is subjected to dynamic regulation during development and upon neuronal activity. It was recently shown to be involved in memory processes but currently, little is known about how it is controlled in the brain during memory formation. Here, we show that Tet3 is selectively up-regulated by activity in hippocampal neurons in vitro, and after formation of fear memory in the hippocampus. This is accompanied by a decrease in miR-29b expression that, through complementary sequences, regulates the level of Tet3 by preferential binding to its 3'UTR. We newly reveal that SAM68, a nuclear RNA-binding protein known to regulate splicing, acts upstream of miR-29 by modulating its biogenesis. Together, these findings identify novel players in the adult brain necessary for the regulation of 5-hmC during memory formation., Scientific Reports, 8 (1), ISSN:2045-2322

International audience; Aging is characterized by progressive memory decline that can lead to dementia when associated with neurodegeneration. Here, we show in mice that aging-related memory decline involves defective biogenesis of microRNAs (miRNAs), in particular miR-183/96/182 cluster, resulting from increased protein phosphatase 1 (PP1) and altered receptor SMAD (R-SMAD) signaling. Correction of the defect by miR-183/96/182 overexpression in hippocampus or by environmental enrichment that normalizes PP1 activity restores memory in aged animals. Regulation of miR-183/96/182 biogenesis is shown to involve the neurodegeneration-related RNA-binding proteins TDP-43 and FUS. Similar alterations in miR-183/96/182, PP1, and R-SMADs are observed in the brains of patients with amyotrophic lateral sclerosis (ALS) or frontotemporal lobar degeneration (FTLD), two neurodegenerative diseases with pathological aggregation of TDP-43. Overall, these results identify new mechanistic links between miR-183/96/182, PP1, TDP-43, and FUS in age-related memory deficits and their reversal.

Recent research has associated metabolic diseases such as diabetes and obesity with a combination of genetic susceptibility and environmental factors or life style. In this combination, mechanisms involving molecules like non-coding RNAs and epigenetic marks like DNA methylation and histone posttranslational modifications have been proposed to act as a molecular bridge between dietary conditions and the genome. Through these mechanisms, dietary changes can influence the genome and in some cases, leave traces that persist across life and can be passed to the progeny. This chapter describes reported cases of inter- or transgenerational transmission of metabolic symptoms resulting from compromised dietary conditions in early life or adulthood in experimental animals and humans. It proposes possible molecular ways by which metabolic signals can influence the epigenome in different cells.

Memory formation is a complex cognitive function regulated by coordinated synaptic and nuclear processes in neurons. In mammals, it is controlled by multiple molecular activators and suppressors, including the key signalling regulator, protein phosphatase 1 (PP1). Here, we show that memory control by PP1 involves the miR-183/96/182 cluster and its selective regulation during memory formation. Inhibiting nuclear PP1 in the mouse brain, or training on an object recognition task similarly increases miR-183/96/182 expression in the hippocampus. Mimicking this increase by miR-183/96/182 overexpression enhances object memory, while knocking-down endogenous miR-183/96/182 impairs it. This effect involves the modulation of several plasticity-related genes, with HDAC9 identified as an important functional target. Further, PP1 controls miR-183/96/182 in a transcription-independent manner through the processing of their precursors. These findings provide novel evidence for a role of miRNAs in memory formation and suggest the implication of PP1 in miRNAs processing in the adult brain., Nature Communications, 7, ISSN:2041-1723

Acute exposure to stressful experiences can rapidly increase anxiety and cause neuropsychiatric disorders. The effects of stress result in part from the release of neurotransmitters and hormones, which regulate gene expression in different brain regions. The fast neuroendocrine response to stress is largely mediated by norepinephrine (NE) and corticotropin releasing hormone (CRH), followed by a slower and more sustained release of corticosterone. While corticosterone is an important regulator of gene expression, it is not clear which stress-signals contribute to the rapid regulation of gene expression observed immediately after stress exposure. Here, we demonstrate in mice that 45 min after an acute swim stress challenge, large changes in gene expression occur across the transcriptome in the hippocampus, a region sensitive to the effects of stress. We identify multiple candidate genes that are rapidly and transiently altered in both males and females. Using a pharmacological approach, we show that most of these rapidly induced genes are regulated by NE through β-adrenergic receptor signaling. We find that CRH and corticosterone can also contribute to rapid changes in gene expression, although these effects appear to be restricted to fewer genes. These results newly reveal a widespread impact of NE on the transcriptome and identify novel genes associated with stress and adrenergic signaling.

Adverse experiences in early life are risk factors for the development of behavioral and physiological symptoms that can lead to psychiatric and cognitive disorders later in life. Some of these symptoms can be transmitted to the offspring, in some cases by non-genomic mechanisms involving germ cells. Using a mouse model of unpredictable maternal separation and maternal stress, we show that postnatal trauma alters coping behaviors in adverse conditions in exposed males when adult and in their adult male progeny. The behavioral changes are accompanied by increased glucocorticoid receptor (GR) expression and decreased DNA methylation of the GR promoter in the hippocampus. DNA methylation is also decreased in sperm cells of exposed males when adult. Transgenerational transmission of behavioral symptoms is prevented by paternal environmental enrichment, an effect associated with the reversal of alterations in GR gene expression and DNA methylation in the hippocampus of the male offspring. These findings highlight the influence of both negative and positive environmental factors on behavior across generations and the plasticity of the epigenome across life.

In the past decades, evidence supporting the transmission of acquired traits across generations has reshaped the field of genetics and the understanding of disease susceptibility. In humans, pioneer studies showed that exposure to famine, endocrine disruptors or trauma can affect descendants, and has led to a paradigm shift in thinking about heredity. Studies in humans have however been limited by the low number of successive generations, the different conditions that can be examined, and the lack of mechanistic insight they can provide. Animal models have been instrumental to circumvent these limitations and allowed studies on the mechanisms of inheritance of environmentally induced traits across generations in controlled and reproducible settings. However, most models available today are only intergenerational and do not demonstrate transmission beyond the direct offspring of exposed individuals. Here, we report transgenerational transmission of behavioral and metabolic phenotypes up to the 4th generation in a mouse model of paternal postnatal trauma (MSUS). Based on large animal numbers (up to 124 per group) from several independent breedings conducted 10 years apart by different experimenters, we show that depressive-like behaviors are transmitted to the offspring until the third generation, and risk-taking and glucose dysregulation until the fourth generation via males. The symptoms are consistent and reproducible, and persist with similar severity across generations. These results provide strong evidence that adverse conditions in early postnatal life can have transgenerational effects, and highlight the validity of MSUS as a solid model of transgenerational epigenetic inheritance., Environmental Epigenetics, 4 (2), ISSN:2058-5888

Traumatic stress is a type of environmental experience that can modify behavior, cognition and physiological functions such as metabolism, in mammals. Many of the effects of traumatic stress can be transmitted to subsequent generations even when individuals from these generations are not exposed to any traumatic stressor. This book chapter discusses the concept of epigenetic/non-genomic inheritance of such traits involving the germline in mammals. It includes a comprehensive review of animal and human studies on inter- and transgenerational inheritance of the effects of traumatic stress, some of the epigenetic changes in the germline currently known to be associated with traumatic stress, and possible mechanisms for their induction and maintenance during development and adulthood. We also describe some experimental interventions that attempted to prevent the transmission of these effects, and consider the evolutionary importance of transgenerational inheritance and future outlook of the field.

Traumatic stress is a type of environmental experience that can modify behavior, cognition and physiological functions such as metabolism, in mammals. Many of the effects of traumatic stress can be transmitted to subsequent generations even when individuals from these generations are not exposed to any traumatic stressor. This book chapter discusses the concept of epigenetic/non-genomic inheritance of such traits involving the germline in mammals. It includes a comprehensive review of animal and human studies on inter- and transgenerational inheritance of the effects of traumatic stress, some of the epigenetic changes in the germline currently known to be associated with traumatic stress, and possible mechanisms for their induction and maintenance during development and adulthood. We also describe some experimental interventions that attempted to prevent the transmission of these effects, and consider the evolutionary importance of transgenerational inheritance and future outlook of the field.

Background Exposure to drugs of abuse alters the epigenetic landscape of the brain's reward regions such as the nucleus accumbens (NAc). We investigated how combinations of chromatin modifications affect genes that regulate responses to cocaine. We focused on autism-candidate 2 ( Auts2 ), a gene linked to human evolution and cognitive disorders, which displays strong clustering of cocaine-induced chromatin modifications in this brain region. Methods We combined chromosome conformation capture (4C and 3C) and related approaches with behavioral paradigms relevant to cocaine phenotypes. Cell type-specific functions were assessed by FACS-sorting and viral-mediated overexpression in Cre-dependent mouse lines. Results We observed that Auts2 gene expression is increased by repeated cocaine administration specifically in D2-type medium spiny neurons (MSNs) in NAc, an effect seen in male but not female mice. Auts2 mRNA expression was also upregulated postmortem in NAc of male human cocaine addicts. We obtained evidence that chromosomal looping, bypassing 1,524 kb of linear genome, connects Auts2 to the calneuron 1 ( Caln1 ) gene locus under baseline conditions. This looping was disrupted after repeated cocaine exposure, resulting in increased expression of both genes in D2 MSNs. Cocaine exposure reduces binding of CTCF, a chromosomal scaffolding protein, and increases histone and DNA methylation, at the Auts-Caln1 loop base in NAc. Cell type-specific overexpression of Auts2 or Caln1 in D2 MSNs demonstrated that both genes promote cocaine reward. Conclusions These findings suggest that cocaine-induced alterations of neuronal 3D genome organization destabilize higher order chromatin at specific loci that regulate responses to the drug.

Handbook of Epigenetics: The New Molecular and Medical Genetics, Second Edition, provides a comprehensive analysis of epigenetics, from basic biology, to clinical application. Epigenetics is considered by many to be the new genetics in that many biological phenomena are controlled, not through gene mutations, but rather through reversible and heritable epigenetic processes. These epigenetic processes range from DNA methylation to prions. The biological processes impacted by epigenetics are vast and encompass effects in lower organisms and humans that include tissue and organ regeneration, X-chromosome inactivation, stem cell differentiation, genomic imprinting, and aging. The first edition of this important work received excellent reviews; the second edition continues its comprehensive coverage adding more current research and new topics based on customer and reader reviews, including new discoveries, approved therapeutics, and clinical trials. From molecular mechanisms and epigenetic technology, to discoveries in human disease and clinical epigenetics, the nature and applications of the science is presented for those with interests ranging from the fundamental basis of epigenetics, to therapeutic interventions for epigenetic-based disorders.