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Kinkead R, Ambrozio-Marques D, Fournier S, Gagnon M, Guay LM. Estrogens, age, and, neonatal stress: panic disorders and novel views on the contribution of non-medullary structures to respiratory control and CO 2 responses. Front Physiol 2023; 14:1183933. [PMID: 37265841 PMCID: PMC10229816 DOI: 10.3389/fphys.2023.1183933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 04/21/2023] [Indexed: 06/03/2023] Open
Abstract
CO2 is a fundamental component of living matter. This chemical signal requires close monitoring to ensure proper match between metabolic production and elimination by lung ventilation. Besides ventilatory adjustments, CO2 can also trigger innate behavioral and physiological responses associated with fear and escape but the changes in brain CO2/pH required to induce ventilatory adjustments are generally lower than those evoking fear and escape. However, for patients suffering from panic disorder (PD), the thresholds for CO2-evoked hyperventilation, fear and escape are reduced and the magnitude of those reactions are excessive. To explain these clinical observations, Klein proposed the false suffocation alarm hypothesis which states that many spontaneous panics occur when the brain's suffocation monitor erroneously signals a lack of useful air, thereby maladaptively triggering an evolved suffocation alarm system. After 30 years of basic and clinical research, it is now well established that anomalies in respiratory control (including the CO2 sensing system) are key to PD. Here, we explore how a stress-related affective disorder such as PD can disrupt respiratory control. We discuss rodent models of PD as the concepts emerging from this research has influenced our comprehension of the CO2 chemosensitivity network, especially structure that are not located in the medulla, and how factors such as stress and biological sex modulate its functionality. Thus, elucidating why hormonal fluctuations can lead to excessive responsiveness to CO2 offers a unique opportunity to gain insights into the neuroendocrine mechanisms regulating this key aspect of respiratory control and the pathophysiology of respiratory manifestations of PD.
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2
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Lapp HE, Margolis AE, Champagne FA. Impact of a bisphenol A, F, and S mixture and maternal care on the brain transcriptome of rat dams and pups. Neurotoxicology 2022; 93:22-36. [PMID: 36041667 PMCID: PMC9985957 DOI: 10.1016/j.neuro.2022.08.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 08/24/2022] [Accepted: 08/24/2022] [Indexed: 01/19/2023]
Abstract
Products containing BPA structural analog replacements have increased in response to growing public concern over adverse effects of BPA. Although humans are regularly exposed to a mixture of bisphenols, few studies have examined effects of prenatal exposure to BPA alternatives or bisphenol mixtures. In the present study, we investigate the effect of exposure to an environmentally-relevant, low-dose (150 ug/kg body weight per day) mixture of BPA, BPS, and BPF during gestation on the brain transcriptome in Long-Evans pups and dams using Tag RNA-sequencing. We also examined the association between dam licking and grooming, which also has enduring effects on pup neural development, and the transcriptomes. Associations between licking and grooming and the transcriptome were region-specific, with the hypothalamus having the greatest number of differentially expressed genes associated with licking and grooming in both dams and pups. Prenatal bisphenol exposure also had region-specific effects on gene expression and pup gene expression was affected more robustly than dam gene expression. In dams, the prelimbic cortex had the greatest number of differentially expressed genes associated with prenatal bisphenol exposure. Prenatal bisphenol exposure changed the expression of over 2000 genes in pups, with the majority being from the pup amygdala. We used Gene Set Enrichment Analysis (GSEA) to asses enrichment of gene ontology biological processes for each region. Top GSEA terms were diverse and varied by brain region and included processes known to have strong associations with steroid hormone regulation, cilium-related terms, metabolic/biosynthetic process terms, and immune terms. Finally, hypothesis-driven analysis of genes related to estrogen response, parental behavior, and epigenetic regulation of gene expression revealed region-specific expression associated with licking and grooming and bisphenol exposure that were distinct in dams and pups. These data highlight the effects of bisphenols on multiple physiological process that are highly dependent on timing of exposure (prenatal vs. adulthood) and brain region, and reiterate the contributions of multiple environmental and experiential factors in shaping the brain.
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Affiliation(s)
- H E Lapp
- Department of Psychology, University of Texas at Austin, 108 E. Dean Keaton St, Austin, TX 78712, USA.
| | - A E Margolis
- Department of Psychiatry, Columbia University Irving Medical Center, 1051 Riverside Drive, New York, NY 10032, USA
| | - F A Champagne
- Department of Psychology, University of Texas at Austin, 108 E. Dean Keaton St, Austin, TX 78712, USA
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3
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Vipin VA, Blesson CS, Yallampalli C. Maternal low protein diet and fetal programming of lean type 2 diabetes. World J Diabetes 2022; 13:185-202. [PMID: 35432755 PMCID: PMC8984567 DOI: 10.4239/wjd.v13.i3.185] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 12/30/2021] [Accepted: 02/10/2022] [Indexed: 02/06/2023] Open
Abstract
Maternal nutrition is found to be the key factor that determines fetal health in utero and metabolic health during adulthood. Metabolic diseases have been primarily attributed to impaired maternal nutrition during pregnancy, and impaired nutrition has been an immense issue across the globe. In recent years, type 2 diabetes (T2D) has reached epidemic proportion and is a severe public health problem in many countries. Although plenty of research has already been conducted to tackle T2D which is associated with obesity, little is known regarding the etiology and pathophysiology of lean T2D, a variant of T2D. Recent studies have focused on the effects of epigenetic variation on the contribution of in utero origins of lean T2D, although other mechanisms might also contribute to the pathology. Observational studies in humans and experiments in animals strongly suggest an association between maternal low protein diet and lean T2D phenotype. In addition, clear sex-specific disease prevalence was observed in different studies. Consequently, more research is essential for the understanding of the etiology and pathophysiology of lean T2D, which might help to develop better disease prevention and treatment strategies. This review examines the role of protein insufficiency in the maternal diet as the central driver of the developmental programming of lean T2D.
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Affiliation(s)
- Vidyadharan Alukkal Vipin
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX 77030, United States
| | - Chellakkan Selvanesan Blesson
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX 77030, United States
- Family Fertility Center, Texas Children's Hospital, Houston, TX 77030, United States
| | - Chandra Yallampalli
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX 77030, United States
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Abstract
Health and lifespan disparities between sexes are dependent on the immune responses. Men and women have different life styles which determine the environment, nutritional requirements and their interactions with the sex hormones. Sexual dimorphism in innate and adaptive immunity determines responses to infections and other environmental factors regulating health and diseases. Sex hormones regulate immune responses through the expression of receptors which differ for female and male hormones. Estrogen receptors are expressed in brain, lymphoid tissue cells and many immune cells while androgen receptors are limited in expression. Genetic, epigenetic factors and X chromosome linked immune function genes are important in enhanced adaptive immunity in females, leading to production of higher levels of antibodies compared to males. Different nutritional requirements and hormonal control of the mucosal microbiome and its function regulate mucosal immunity. Hormonal changes during various aspects of life and during aging control immune senescence. Evolutionarily, females have an advantage during young age when they are protected from infections by heightened immune reactivity though during aging that can lead to pathologies. Considering the sexual dimorphism in immunity, guidelines need to be established for sex-based treatments for optimal response.
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Affiliation(s)
- Veena Taneja
- Department of Immunology and Rheumatology, Mayo Clinic, Rochester, MN, United States.
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5
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Fu H, Yang T, Wang T, Wu X, Xia N, Feng T. Effect of adverse childhood experiences and DNA methylation on male sexual orientation. ZHONG NAN DA XUE XUE BAO. YI XUE BAN = JOURNAL OF CENTRAL SOUTH UNIVERSITY. MEDICAL SCIENCES 2021; 46:91-97. [PMID: 33678642 PMCID: PMC10878294 DOI: 10.11817/j.issn.1672-7347.2021.190280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Indexed: 11/03/2022]
Abstract
The causes for male sexual orientation are complicated, which have not yet been clarified. Recent years have witnessed fruitful progress in the field of biology, while the impact of environment has received little attention. Adverse childhood experiences (ACEs), identified as a special environment in the early stage of development, can affect the individual phenotype by DNA methylation. Given the relationships among male sexual orientation, ACEs, and DNA methylation, as well as based on the existing theory, this article proposes the model "ACEs-DNA methylation-male sexual orientation"from the perspective of environment and epigenetics, aiming to provide a theoretical basis for future research.
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Affiliation(s)
- Hanlin Fu
- Shenzhen Center for Chronic Disease Control, Shenzhen Guangdong 518020.
- Xiangya School of Public Health, Central South University, Changsha 410078, China.
| | - Tubao Yang
- Xiangya School of Public Health, Central South University, Changsha 410078, China
| | - Tingting Wang
- Xiangya School of Public Health, Central South University, Changsha 410078, China
| | - Xiaobing Wu
- Shenzhen Center for Chronic Disease Control, Shenzhen Guangdong 518020
| | - Nan Xia
- Shenzhen Center for Chronic Disease Control, Shenzhen Guangdong 518020
- Xiangya School of Public Health, Central South University, Changsha 410078, China
| | - Tiejian Feng
- Shenzhen Center for Chronic Disease Control, Shenzhen Guangdong 518020.
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6
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Novel sex-specific influence of parental factors on small-for-gestational-age newborns. Sci Rep 2020; 10:19226. [PMID: 33154528 PMCID: PMC7644766 DOI: 10.1038/s41598-020-76196-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 10/23/2020] [Indexed: 11/09/2022] Open
Abstract
Since fetal programming is sex-specific, there may also be sex-specific in parental influences on newborn birth weight. We aimed to investigate the influence of parental factors on small-for-gestational-age (SGA) infants of different sexes. Based on a pre-pregnancy cohort, multivariate logistic regression was used. 2275 couples were included for analysis. Significant associations were observed among paternal height, pre-pregnancy body mass index (BMI), and SGA in male infants; among maternal height, pre-pregnancy BMI, and SGA in female infants, and among other maternal factors and SGA in both male and female infants. Such sex specificity may be related to genetic, epigenetic, or hormonal influences between parents and infants. In conclusion, there is a sex specificity in the effect of parental height and pre-pregnancy BMI on SGA. The data suggest that future studies on infants should consider the sex-specific differences between the effects of genetic or environmental factors and infants.
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Eck SR, Ardekani CS, Salvatore M, Luz S, Kim ED, Rogers CM, Hall A, Lee DE, Famularo ST, Bhatnagar S, Bangasser DA. The effects of early life adversity on growth, maturation, and steroid hormones in male and female rats. Eur J Neurosci 2020; 52:2664-2680. [PMID: 31660665 PMCID: PMC8027906 DOI: 10.1111/ejn.14609] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 10/18/2019] [Accepted: 10/23/2019] [Indexed: 02/06/2023]
Abstract
Early life adversity is a risk factor for psychiatric disorders, yet the mechanisms by which adversity increases this risk are still being delineated. Here, we used a limited bedding and nesting (LBN) manipulation in rats that models a low resource environment to examine effects on growth, developmental milestones, and endocrine endpoints. In LBN, dams and pups, from pups' postnatal days 2-9, are exposed to an environment where dams lack proper materials to build a nest. This manipulation is compared to control housing conditions, where rat dams have access to ample nesting materials and enrichment throughout pups' development. We found that the LBN condition altered maternal care, increasing pup-directed behaviors while reducing self-care. This, perhaps compensatory, increase in nursing and attention to pups did not mitigate against changes in metabolism, as LBN reduced weight gain in both sexes and this effect persisted into adulthood. Although adult stress hormone levels in both sexes and vaginal opening and estrous cycle length in females were not disrupted, there was other evidence of endocrine dysregulation. Compared to controls, LBN rats of both sexes had shortened anogenital distances, indicating reduced androgen exposure. LBN males also had higher plasma estradiol levels in adulthood. This combination of results suggests that LBN causes a demasculinizing effect in males that could contribute to lasting changes in the brain and behavior. Importantly, alterations in metabolic and endocrine systems due to early life adversity could be one mechanism by which stress early in life increases risk for later disease.
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Affiliation(s)
- Samantha R. Eck
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122, USA
| | - Cory S. Ardekani
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122, USA
| | - Madeleine Salvatore
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122, USA
| | - Sandra Luz
- Department of Anesthesiology and Critical Care, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Eric D. Kim
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122, USA
| | - Charleanne M. Rogers
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122, USA
| | - Arron Hall
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122, USA
| | - Demetrius E. Lee
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122, USA
| | - Sydney T. Famularo
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122, USA
| | - Seema Bhatnagar
- Department of Anesthesiology and Critical Care, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA,University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Debra A. Bangasser
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122, USA
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Psychiatric Disorders in the Adolescent Offspring of Mothers with Thyroid Problems During Pregnancy. Child Psychiatry Hum Dev 2020; 51:461-470. [PMID: 32008126 DOI: 10.1007/s10578-020-00957-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Maternal thyroid problems during pregnancy have been linked to neurocognitive impairments in children. While studies suggest that disorders of maternal thyroid function during pregnancy are associated with symptoms of mental health problems in children, little is known about the risk of clinically significant psychiatric disorders in adolescence. A sample of 2451 Canadian adolescents enrolled in the Ontario Child Health Study completed the Mini International Neuropsychiatric Interview for Children and Adolescents at 12-17 years of age. Their mothers self-reported thyroid problems during pregnancy. Gestational thyroid problems were associated with offspring oppositional defiant disorder (ODD; OR 3.73; 95% CI 1.69-8.24), conduct disorder (CD; OR 12.95; 95% CI 5.12-32.75), and social anxiety disorder (SAD; OR 6.25; 95% CI 2.53-15.47). Neither sex nor gestational age moderated associations between prenatal thyroid dysfunction and the majority of outcomes. School performance mediated 8% of the association between thyroid problems and SAD, 21% for CD and 53% for ODD.
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Massa MG, Correa SM. Sexes on the brain: Sex as multiple biological variables in the neuronal control of feeding. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165840. [PMID: 32428559 DOI: 10.1016/j.bbadis.2020.165840] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 05/05/2020] [Accepted: 05/13/2020] [Indexed: 12/21/2022]
Abstract
Neuronal interactions at the level of vagal, homeostatic, and hedonic circuitry work to regulate the neuronal control of feeding. This integrative system appears to vary across sex and gender in the animal and human worlds. Most feeding research investigating these variations across sex and gender focus on how the organizational and activational mechanisms of hormones contribute to these differences. However, in limited studies spanning both the central and peripheral nervous systems, sex differences in feeding have been shown to manifest not just at the level of the hormonal, but also at the chromosomal, epigenetic, cellular, and even circuitry levels to alter food intake. In this review, we provide a brief orientation to the current understanding of how these neuronal systems interact before dissecting selected studies from the recent literature to exemplify how feeding physiology at all levels can be affected by the various components of sex.
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Affiliation(s)
- Megan G Massa
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, United States of America; Laboratory of Neuroendocrinology of the Brain Research Institute, University of California, Los Angeles, CA, United States of America; Neuroscience Interdepartmental Doctoral Program, University of California, Los Angeles, CA, United States of America.
| | - Stephanie M Correa
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, United States of America; Laboratory of Neuroendocrinology of the Brain Research Institute, University of California, Los Angeles, CA, United States of America.
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10
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Neonatal treatment with clomipramine modifies the expression of estrogen receptors in brain areas of male adult rats. Brain Res 2019; 1724:146443. [DOI: 10.1016/j.brainres.2019.146443] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 09/04/2019] [Accepted: 09/08/2019] [Indexed: 01/03/2023]
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11
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Early life stress and the propensity to develop addictive behaviors. Int J Dev Neurosci 2019; 78:156-169. [PMID: 31255718 DOI: 10.1016/j.ijdevneu.2019.06.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 06/03/2019] [Accepted: 06/13/2019] [Indexed: 12/14/2022] Open
Abstract
There is a vast literature on effects of early life manipulations in rodents much of which is aimed at investigating the long-term consequences related to emotion and cognition in adulthood. Less is known about how these manipulations affect responses reflective of alcohol (AUD) and substance (SUD) use disorders. The purpose of this paper is to review the literature of studies that employed early life manipulations and assessed behavioral responses to psychoactive substances, specifically alcohol, opiates, and stimulants, in rodents. While the findings with alcohol are more limited and mixed, studies with opiates and stimulants show strong support for the ability of these manipulations to enhance behavioral responsivity to these substances in line with epidemiological data. Some outcomes show sex differences. The mechanisms that influence these enduring changes may reflect epigenetic alterations. Several studies support a role for altered DNA methylation (and other epigenetic mechanisms) as biological responses to early environmental insults. The chemical changes induced by DNA methylation affect transcriptional activity of DNA and thus can have a long-term impact on the individual's phenotype. Such effects are particularly robust when they occur during sensitive periods of brain development (e.g., first postnatal weeks in rodents). We review this emerging literature as it relates to the known neurobiology of AUDs and SUDs and suggest new avenues of research. Such findings will have implications for the treatment and prevention of AUDs and SUDs and could provide insight into factors that support resiliency.
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12
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Gegenhuber B, Tollkuhn J. Sex Differences in the Epigenome: A Cause or Consequence of Sexual Differentiation of the Brain? Genes (Basel) 2019; 10:genes10060432. [PMID: 31181654 PMCID: PMC6627918 DOI: 10.3390/genes10060432] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 05/29/2019] [Accepted: 06/03/2019] [Indexed: 12/19/2022] Open
Abstract
Females and males display differences in neural activity patterns, behavioral responses, and incidence of psychiatric and neurological diseases. Sex differences in the brain appear throughout the animal kingdom and are largely a consequence of the physiological requirements necessary for the distinct roles of the two sexes in reproduction. As with the rest of the body, gonadal steroid hormones act to specify and regulate many of these differences. It is thought that transient hormonal signaling during brain development gives rise to persistent sex differences in gene expression via an epigenetic mechanism, leading to divergent neurodevelopmental trajectories that may underlie sex differences in disease susceptibility. However, few genes with a persistent sex difference in expression have been identified, and only a handful of studies have employed genome-wide approaches to assess sex differences in epigenomic modifications. To date, there are no confirmed examples of gene regulatory elements that direct sex differences in gene expression in the brain. Here, we review foundational studies in this field, describe transcriptional mechanisms that could act downstream of hormone receptors in the brain, and suggest future approaches for identification and validation of sex-typical gene programs. We propose that sexual differentiation of the brain involves self-perpetuating transcriptional states that canalize sex-specific development.
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Affiliation(s)
- Bruno Gegenhuber
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
| | - Jessica Tollkuhn
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
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Aylwin CF, Toro CA, Shirtcliff E, Lomniczi A. Emerging Genetic and Epigenetic Mechanisms Underlying Pubertal Maturation in Adolescence. JOURNAL OF RESEARCH ON ADOLESCENCE : THE OFFICIAL JOURNAL OF THE SOCIETY FOR RESEARCH ON ADOLESCENCE 2019; 29:54-79. [PMID: 30869843 DOI: 10.1111/jora.12385] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The adolescent transition begins with the onset of puberty which, upstream in the brain, is initiated by the gonadotropin-releasing hormone (GnRH) pulse generator that activates the release of peripheral sex hormones. Substantial research in human and animal models has revealed a myriad of cellular networks and heritable genes that control the GnRH pulse generator allowing the individual to begin the process of reproductive competence and sexual maturation. Here, we review the latest knowledge in neuroendocrine pubertal research with emphasis on genetic and epigenetic mechanisms underlying the pubertal transition.
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14
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Cortes LR, Cisternas CD, Forger NG. Does Gender Leave an Epigenetic Imprint on the Brain? Front Neurosci 2019; 13:173. [PMID: 30872999 PMCID: PMC6400866 DOI: 10.3389/fnins.2019.00173] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 02/13/2019] [Indexed: 01/21/2023] Open
Abstract
The words “sex” and “gender” are often used interchangeably in common usage. In fact, the Merriam-Webster dictionary offers “sex” as the definition of gender. The authors of this review are neuroscientists, and the words “sex” and “gender” mean very different things to us: sex is based on biological factors such as sex chromosomes and gonads, whereas gender has a social component and involves differential expectations or treatment by conspecifics, based on an individual’s perceived sex. While we are accustomed to thinking about “sex” and differences between males and females in epigenetic marks in the brain, we are much less used to thinking about the biological implications of gender. Nonetheless, careful consideration of the field of epigenetics leads us to conclude that gender must also leave an epigenetic imprint on the brain. Indeed, it would be strange if this were not the case, because all environmental influences of any import can epigenetically change the brain. In the following pages, we explain why there is now sufficient evidence to suggest that an epigenetic imprint for gender is a logical conclusion. We define our terms for sex, gender, and epigenetics, and describe research demonstrating sex differences in epigenetic mechanisms in the brain which, to date, is mainly based on work in non-human animals. We then give several examples of how gender, rather than sex, may cause the brain epigenome to differ in males and females, and finally consider the myriad of ways that sex and gender interact to shape gene expression in the brain.
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Affiliation(s)
- Laura R Cortes
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Carla D Cisternas
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Nancy G Forger
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
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15
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Ratnu VS, Emami MR, Bredy TW. Genetic and epigenetic factors underlying sex differences in the regulation of gene expression in the brain. J Neurosci Res 2017; 95:301-310. [PMID: 27870402 DOI: 10.1002/jnr.23886] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 07/13/2016] [Accepted: 07/25/2016] [Indexed: 12/14/2022]
Abstract
There are inherent biological differences between males and females that contribute to sex differences in brain function and to many sex-specific illnesses and disorders. Traditionally, it has been thought that such differences are due largely to hormonal regulation; however, there are also genetic and epigenetic effects caused by the inheritance and unequal dosage of genes located on the X and Y chromosomes. Here we discuss the evidence in favor of a genetic and epigenetic basis for sexually dimorphic behavior, as a consequence of underlying differences in the regulation of genes that drive brain function. A better understanding of sex-specific molecular processes in the brain will provide further insight for the development of novel therapeutic approaches for the treatment of neuropsychiatric disorders characterized by sex differences. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Vikram S Ratnu
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Michael R Emami
- Department of Neurobiology and Behavior, University of California, Irvine, California
| | - Timothy W Bredy
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia.,Department of Neurobiology and Behavior, University of California, Irvine, California
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16
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Ghosh S, Klein RS. Sex Drives Dimorphic Immune Responses to Viral Infections. THE JOURNAL OF IMMUNOLOGY 2017; 198:1782-1790. [PMID: 28223406 DOI: 10.4049/jimmunol.1601166] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 10/24/2016] [Indexed: 02/07/2023]
Abstract
New attention to sexual dimorphism in normal mammalian physiology and disease has uncovered a previously unappreciated breadth of mechanisms by which females and males differentially exhibit quantitative phenotypes. Thus, in addition to the established modifying effects of hormones, which prenatally and postpubertally pattern cells and tissues in a sexually dimorphic fashion, sex differences are caused by extragonadal and dosage effects of genes encoded on sex chromosomes. Sex differences in immune responses, especially during autoimmunity, have been studied predominantly within the context of sex hormone effects. More recently, immune response genes have been localized to sex chromosomes themselves or found to be regulated by sex chromosome genes. Thus, understanding how sex impacts immunity requires the elucidation of complex interactions among sex hormones, sex chromosomes, and immune response genes. In this Brief Review, we discuss current knowledge and new insights into these intricate relationships in the context of viral infections.
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Affiliation(s)
- Soumitra Ghosh
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Robyn S Klein
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110; .,Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110; and.,Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110
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17
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Yohn CN, Leithead AB, Becker EA. Increased vasopressin expression in the BNST accompanies paternally induced territoriality in male and female California mouse offspring. Horm Behav 2017; 93:9-17. [PMID: 28359742 DOI: 10.1016/j.yhbeh.2017.03.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 03/17/2017] [Accepted: 03/19/2017] [Indexed: 01/16/2023]
Abstract
While developmental consequences of parental investment on species-typical social behaviors has been extensively characterized in same-sex parent-offspring interactions, the impact of opposite-sex relationships is less clear. In the bi-parental California mouse (Peromyscus californicus), paternal retrieval behavior induces territorial aggression and the expression of arginine vasopressin (AVP) in adult male offspring. Although similar patterns of territorially emerge among females, the sexually dimorphic AVP system has not been considered since it is generally thought to regulate male-typical behavior. However, we recently demonstrated that male and female P. californicus offspring experience increases in plasma testosterone following paternal retrieval. Since AVP expression is androgen-dependent during development, we postulate that increases in AVP expression may accompany territoriality in female, as well as male offspring. To explore this aim, adult P. californicus offspring that received either high or low levels of paternal care (retrievals) during early development were tested for territoriality and immunohistochemical analysis of AVP within the bed nucleus of the stria terminalis (BNST), paraventricular nucleus (PVN), and supraoptic nucleus (SON). Consistent with previous studies, high care offspring were more aggressive than low care offspring. Moreover, high care offspring had significantly more AVP immunoreactive (AVP-ir) cells within the BNST than low care offspring. This pattern was observed within female as well as male offspring, suggesting an equally salient role for paternal care on female offspring physiology. Regardless of early social experience, sex differences in AVP persisted in the BNST, with males having greater expression than females.
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Affiliation(s)
- Christine N Yohn
- Department of Psychology, Saint Joseph's University, 5600 City Avenue, Philadelphia, PA 19131, USA; Department of Psychology, Rutgers University, 152 Frelinghuysen Rd, Piscataway, NJ 08854, USA.
| | - Amanda B Leithead
- Department of Psychology, Saint Joseph's University, 5600 City Avenue, Philadelphia, PA 19131, USA
| | - Elizabeth A Becker
- Department of Psychology, Saint Joseph's University, 5600 City Avenue, Philadelphia, PA 19131, USA
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18
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Wright EC, Johnson SA, Hao R, Kowalczyk AS, Greenberg GD, Sanchez EO, Laman-Maharg A, Trainor BC, Rosenfeld CS. Exposure to extrinsic stressors, social defeat or bisphenol A, eliminates sex differences in DNA methyltransferase expression in the amygdala. J Neuroendocrinol 2017; 29:10.1111/jne.12475. [PMID: 28406523 PMCID: PMC5501704 DOI: 10.1111/jne.12475] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 03/22/2017] [Accepted: 03/30/2017] [Indexed: 12/24/2022]
Abstract
Chemical and psychological stressors can exert long lasting changes in brain function and behaviour. Changes in DNA methylation have been shown to be an important mechanism mediating long lasting changes in neural function and behaviour, especially for anxiety-like or stress responses. In the present study, we examined the effects of either a social or chemical stressor on DNA methyltransferase (DNMT) gene expression in the amygdala, an important brain region modulating stress responses and anxiety. In adult California mice (Peromyscus californicus) that were naïve to social defeat, females had higher levels of Dnmt1 expression in punch samples of the central amygdala (CeA) than males. In addition, mice that underwent social defeat stress showed reduced Dnmt1 and Dnmt3a expression in the CeA of females but not males. A second study using more anatomically specific punch samples replicated these effects for Dnmt1. Perinatal exposure (spanning from periconception through lactation) to bisphenol A or ethinyl oestradiol (oestrogens in birth control pills) also abolished sex differences in Dnmt1 expression in the CeA but not the basolateral amygdala. These findings identify a robust sex difference in Dnmt1 expression in the CeA that is sensitive to both psychological and chemical stressors. Future studies should aim to examine the impact of psychological and chemical stressors on DNA methylation in the CeA and also investigate whether Dnmt1 may have an underappreciated role in plasticity in behaviour.
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Affiliation(s)
- Emily C. Wright
- Department of Psychology, University of California, Davis, CA, USA
| | - Sarah A. Johnson
- Bond Life Science Center, Department of Biomedical Sciences, Department of Animal Science, University of Missouri, Columbia, MO, USA
| | - Rebecca Hao
- Department of Psychology, University of California, Davis, CA, USA
| | | | - Gian D. Greenberg
- Neuroscience Graduate Group, University of California, Davis, CA, USA
| | | | | | - Brian C. Trainor
- Department of Psychology, University of California, Davis, CA, USA
- Neuroscience Graduate Group, University of California, Davis, CA, USA
| | - Cheryl S. Rosenfeld
- Bond Life Science Center, Department of Biomedical Sciences, Department of Animal Science, University of Missouri, Columbia, MO, USA
- Genetics Area Program and Thompson Center for Autism and Neurobehavioral Disorders, University of Missouri, Columbia, MO, USA
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19
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Ianov L, Kumar A, Foster TC. Epigenetic regulation of estrogen receptor α contributes to age-related differences in transcription across the hippocampal regions CA1 and CA3. Neurobiol Aging 2016; 49:79-85. [PMID: 27776265 DOI: 10.1016/j.neurobiolaging.2016.09.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 09/20/2016] [Accepted: 09/20/2016] [Indexed: 10/20/2022]
Abstract
The expression of estrogen receptor alpha (ERα) varies across brain regions and changes with age and according to the previous history of estradiol exposure. ERα is regulated by a number of mechanisms including the level of mRNA (Esr1) expression. For this study, we took advantage of regional differences in hippocampal ERα expression to investigate DNA ERα promoter methylation at CpG dinucleotide sites as a potential epigenetic mechanism for regulating gene expression. Young and aged female Fischer 344 rats were ovariectomized, and Esr1 expression and ERα promoter methylation were examined in hippocampal regions CA1 and CA3, either 3 or 14 weeks following surgery. The results indicate that reduced Esr1 expression in region CA1 relative to CA3 was associated with an increase in DNA methylation in region CA1, particularly for the first CpG site. Additionally, differential methylation of distal CpG sites, 11-17, was associated with altered Esr1 expression during aging or following long-term hormone deprivation. The results support the idea that methylation of site 1 may be the primary regulatory region for cross-regional patterns in ERα expression, while distal sites are modifiable across the life span and may act as a feedback mechanism for ERα activity.
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Affiliation(s)
- Lara Ianov
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA; Genetics and Genomics Program, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA.
| | - Thomas C Foster
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA; Genetics and Genomics Program, Genetics Institute, University of Florida, Gainesville, FL, USA.
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20
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Sanchis-Segura C, Becker JB. Why we should consider sex (and study sex differences) in addiction research. Addict Biol 2016; 21:995-1006. [PMID: 27029841 DOI: 10.1111/adb.12382] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 02/02/2016] [Indexed: 12/31/2022]
Abstract
Among mammals, every cell has a biological sex, and the sex of an individual pervades its body and brain. In this review, we describe the processes through which mammals become phenotypically male or female by organizational and activational influences of genes and hormones throughout development. We emphasized that the molecular and cellular changes triggered by sex chromosomes and steroid hormones may generate sex differences in overt physiological functions and behavior, but they may alternatively promote end-point convergences between males and females. Clinical and pre-clinical evidences suggest that sex and gender differences modulate drug consumption as well as of the transition towards drug-promoted pathological states such as dependence and addiction. Additionally, sex differences in drug pharmacokinetics and pharmacodynamics will also influence dependence and addiction as well as side effects of drugs. These effects will further interact with socially gendered factors to result in sex differences in the access to, engagement in and efficacy of any therapeutic attempt. Finally, we maintain that 'sex sameness' is as important as 'sex differences' when building a complete understanding of biology for both males and females and provide a framework with which to classify and guide investigation into the mechanisms mediating sex differences and sex sameness.
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Affiliation(s)
- Carla Sanchis-Segura
- Departament de Psicologia básica, clínica i psicobiologia. Área de Psicobiología; Universitat Jaume I; Castellón de la Plana Spain
| | - Jill B. Becker
- Department of Psychology and Molecular and Behavioral Neuroscience Institute; University of Michigan; Ann Arbor MI USA
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21
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Kigar SL, Chang L, Hayne MR, Karls NT, Auger AP. Sex differences in Gadd45b expression and methylation in the developing rodent amygdala. Brain Res 2016; 1642:461-466. [PMID: 27086974 PMCID: PMC6701186 DOI: 10.1016/j.brainres.2016.04.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 04/12/2016] [Accepted: 04/14/2016] [Indexed: 01/25/2023]
Abstract
Precise spatiotemporal epigenetic regulation of the genome facilitates species-typical development; sexual differentiation of the brain by gonadal hormones and sex chromosomes causes extensive epigenetic reprogramming of many cells in the body, including the brain, and may indirectly predispose males and females to different psychiatric conditions. We and others have demonstrated sex differences in DNA methylation, as well as in the enzymes that form, or 'write', this epigenetic modification. However, while a growing body of evidence suggests that DNA methylation undergoes rapid turnover and is dynamically regulated in vivo, to our knowledge no studies have been done investigating whether sex differences exist in the epigenetic 'erasers' during postnatal development. Here we report sex differences in the expression of growth arrest and DNA damage inducible factor β (Gadd45b), but not family members α (a) or γ (g), in the neonatal and juvenile rodent amygdala.
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Affiliation(s)
- Stacey L Kigar
- Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, 1202 W Johnson St., Madison, WI 53706, United States.
| | - Liza Chang
- Department of Psychology, University of Wisconsin-Madison, 1202 W Johnson St., Madison, WI 53706, United States.
| | - Margaret R Hayne
- Department of Psychology, University of Wisconsin-Madison, 1202 W Johnson St., Madison, WI 53706, United States
| | - Nicolette T Karls
- Department of Psychology, University of Wisconsin-Madison, 1202 W Johnson St., Madison, WI 53706, United States
| | - Anthony P Auger
- Department of Psychology, University of Wisconsin-Madison, 1202 W Johnson St., Madison, WI 53706, United States; Neuroscience Training Program, University of Wisconsin-Madison, 1202 W Johnson St., Madison, WI 53706, United States.
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22
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Curley JP, Champagne FA. Influence of maternal care on the developing brain: Mechanisms, temporal dynamics and sensitive periods. Front Neuroendocrinol 2016; 40:52-66. [PMID: 26616341 PMCID: PMC4783284 DOI: 10.1016/j.yfrne.2015.11.001] [Citation(s) in RCA: 158] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 11/17/2015] [Accepted: 11/22/2015] [Indexed: 02/08/2023]
Abstract
Variation in maternal care can lead to divergent developmental trajectories in offspring with implications for neuroendocrine function and behavioral phenotypes. Study of the long-term outcomes associated with mother-infant interactions suggests complex mechanisms linking the experience of variation in maternal care and these neurobiological consequences. Through integration of genetic, molecular, cellular, neuroanatomical, and neuroendocrine approaches, significant advances in our understanding of these complex pathways have been achieved. In this review, we will consider the impact of maternal care on male and female offspring development with a particular focus on the issues of timing and mechanism. Identifying the period of sensitivity to maternal care and the temporal dynamics of the molecular and neuroendocrine changes that are a consequence of maternal care represents a critical step in the study of mechanism.
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Affiliation(s)
- James P Curley
- Department of Psychology, Columbia University, Room 406 Schermerhorn Hall, 1190 Amsterdam Avenue, New York, NY 10027, USA; Center for Integrative Animal Behavior, Columbia University, 1200 Amsterdam Avenue, New York, NY 10027, USA.
| | - Frances A Champagne
- Department of Psychology, Columbia University, Room 406 Schermerhorn Hall, 1190 Amsterdam Avenue, New York, NY 10027, USA; Center for Integrative Animal Behavior, Columbia University, 1200 Amsterdam Avenue, New York, NY 10027, USA.
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23
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Forger NG, Strahan JA, Castillo-Ruiz A. Cellular and molecular mechanisms of sexual differentiation in the mammalian nervous system. Front Neuroendocrinol 2016; 40:67-86. [PMID: 26790970 PMCID: PMC4897775 DOI: 10.1016/j.yfrne.2016.01.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 12/31/2015] [Accepted: 01/09/2016] [Indexed: 01/16/2023]
Abstract
Neuroscientists are likely to discover new sex differences in the coming years, spurred by the National Institutes of Health initiative to include both sexes in preclinical studies. This review summarizes the current state of knowledge of the cellular and molecular mechanisms underlying sex differences in the mammalian nervous system, based primarily on work in rodents. Cellular mechanisms examined include neurogenesis, migration, the differentiation of neurochemical and morphological cell phenotype, and cell death. At the molecular level we discuss evolving roles for epigenetics, sex chromosome complement, the immune system, and newly identified cell signaling pathways. We review recent findings on the role of the environment, as well as genome-wide studies with some surprising results, causing us to re-think often-used models of sexual differentiation. We end by pointing to future directions, including an increased awareness of the important contributions of tissues outside of the nervous system to sexual differentiation of the brain.
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Affiliation(s)
- Nancy G Forger
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, United States.
| | - J Alex Strahan
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, United States.
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24
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Guintivano J, Kaminsky ZA. Role of epigenetic factors in the development of mental illness throughout life. Neurosci Res 2016; 102:56-66. [DOI: 10.1016/j.neures.2014.08.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 07/31/2014] [Accepted: 08/04/2014] [Indexed: 12/15/2022]
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25
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Stolzenberg DS, Champagne FA. Hormonal and non-hormonal bases of maternal behavior: The role of experience and epigenetic mechanisms. Horm Behav 2016; 77:204-10. [PMID: 26172856 DOI: 10.1016/j.yhbeh.2015.07.005] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 07/06/2015] [Accepted: 07/07/2015] [Indexed: 11/24/2022]
Abstract
This article is part of a Special Issue "Parental Care". Though hormonal changes occurring throughout pregnancy and at the time of parturition have been demonstrated to prime the maternal brain and trigger the onset of mother-infant interactions, extended experience with neonates can induce similar behavioral interactions. Sensitization, a phenomenon in which rodents engage in parental responses to young following constant cohabitation with donor pups, was elegantly demonstrated by Rosenblatt (1967) to occur in females and males, independent of hormonal status. Study of the non-hormonal basis of maternal behavior has contributed significantly to our understanding of hormonal influences on the maternal brain and the cellular and molecular mechanisms that mediate maternal behavior. Here, we highlight our current understanding regarding both hormone-induced and experience-induced maternal responsivity and the mechanisms that may serve as a common pathway through which increases in maternal behavior are achieved. In particular, we describe the epigenetic changes that contribute to chromatin remodeling and how these molecular mechanisms may influence the neural substrates of the maternal brain. We also consider how individual differences in these systems emerge during development in response to maternal care. This research has broad implications for our understanding of the parental brain and the role of experience in the induction of neurobiological and behavior changes.
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26
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McCarthy MM, Nugent BM. At the frontier of epigenetics of brain sex differences. Front Behav Neurosci 2015; 9:221. [PMID: 26347630 PMCID: PMC4543874 DOI: 10.3389/fnbeh.2015.00221] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 08/07/2015] [Indexed: 11/28/2022] Open
Abstract
The notion that epigenetics may play an important role in the establishment and maintenance of sex differences in the brain has garnered great enthusiasm but the reality in terms of actual advances has been slow. Two general approaches include the comparison of a particular epigenetic mark in males vs. females and the inhibition of key epigenetic enzymes or co-factors to determine if this eliminates a particular sex difference in brain or behavior. The majority of emphasis has been on candidate genes such as steroid receptors. Only recently have more generalized survey type approaches been achieved and these promise to open new vistas and accelerate discovery of important roles for DNA methylation, histone modification, genomic imprinting and microRNAs (miRs). Technical challenges abound and, while not unique to this field, will require novel thinking and new approaches by behavioral neuroendocrinologists.
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Affiliation(s)
- Margaret M McCarthy
- Department of Pharmacology, University of Maryland School of Medicine Baltimore, MD, USA
| | - Bridget M Nugent
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania Philadelphia, PA, USA
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27
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Matsuda KI. Epigenetic changes in the estrogen receptor α gene promoter: implications in sociosexual behaviors. Front Neurosci 2014; 8:344. [PMID: 25389384 PMCID: PMC4211403 DOI: 10.3389/fnins.2014.00344] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 10/09/2014] [Indexed: 11/23/2022] Open
Abstract
Estrogen action through estrogen receptor α (ERα) is involved in the control of sexual and social behaviors in adult mammals. Alteration of ERα gene activity mediated by epigenetic mechanisms, such as histone modifications and DNA methylation, in particular brain areas appears to be crucial for determining the extents of these behaviors between the sexes and among individuals within the same sex. This review provides a summary of the epigenetic changes in the ERα gene promoter that correlate with sociosexual behaviors.
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Affiliation(s)
- Ken Ichi Matsuda
- Department of Anatomy and Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine Kyoto, Japan
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28
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Kosten TA, Nielsen DA. Litter and sex effects on maternal behavior and DNA methylation of the Nr3c1 exon 17 promoter gene in hippocampus and cerebellum. Int J Dev Neurosci 2014; 36:5-12. [PMID: 24721039 PMCID: PMC4101021 DOI: 10.1016/j.ijdevneu.2014.03.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 03/28/2014] [Accepted: 03/28/2014] [Indexed: 01/03/2023] Open
Abstract
Early life events can alter gene expression through DNA methylation. The methylation status of the exon 17 promoter of the glucocorticoid receptor (Nr3c1 gene) in hippocampus associates with frequency of pup licking. Much of this work was conducted with male rats. Because dams more frequently lick male pups, this may contribute to sex differences in phenotypes through DNA methylation. Modifying litter gender composition (LGC), in which offspring of single-sex litters are compared to mixed-sex litters, alters maternal behavior. Previously, we demonstrated that LGC and sex affected pup licking times as well as anxiety and hippocampal DNA methylation of the Nr3c1 exon 17 promoter gene in adolescence. Now, we expand upon this work by examining effects in cerebellum and measuring mRNA levels. We also re-assessed DNA methylation in hippocampus using pyrosequencing and re-analyzed pup licking with the more commonly used frequency measure. Litters, culled to 8 pups on postnatal day 1 (PN1), were assigned to one of three conditions: all male (n = 10), all female (n = 12), or half of each sex (n = 20). Licking was rated on PN4, 7, and 10. On PN35, hippocampal and cerebellar samples were obtained. Single-sex males were licked the least and mixed-sex males, the most. Hippocampal Nr3c1 mRNA levels were lowest in mixed females with no LGC or Sex effects in DNA methylation. Cerebellar DNA methylation levels were lowest in mixed males with no effect on mRNA levels. Maternal pup licking associated with DNA methylation of the Nr3c1 exon 17 promoter gene in cerebellum and with hippocampal mRNA.
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Affiliation(s)
- Therese A Kosten
- Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine and Michael E DeBakey Veteran's Affairs Medical Center, Houston, TX 77030, United States.
| | - David A Nielsen
- Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine and Michael E DeBakey Veteran's Affairs Medical Center, Houston, TX 77030, United States
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29
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Vázquez-Martínez ER, Mendoza-Garcés L, Vergara-Castañeda E, Cerbón M. Epigenetic regulation of Progesterone Receptor isoforms: from classical models to the sexual brain. Mol Cell Endocrinol 2014; 392:115-24. [PMID: 24859604 DOI: 10.1016/j.mce.2014.05.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 05/12/2014] [Indexed: 01/29/2023]
Abstract
Progesterone Receptor is a member of the nuclear receptor superfamily, which regulates several functions in both reproductive and non-reproductive tissues. Progesterone Receptor gene encodes for two main isoforms, A and B, and contains two specific promoters with their respective transcription start sites. The mRNA expression of both isoforms is mainly regulated by estrogens and specifically via the Estrogen Receptor Alpha, in a context specific manner. Furthermore, it has been reported in extensive physiological and pathological models that Progesterone Receptor isoforms regulation is related to the epigenetic state of their respective promoters. Epigenetic regulation of Progesterone Receptor isoforms in the brain is a recent and scarcely explored field in neurosciences. This review focuses on the epigenetic mechanisms involved in Progesterone Receptor regulation, emphasizing the implications for the sexual brain. Future directions for research about this important field are also discussed.
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Affiliation(s)
- Edgar Ricardo Vázquez-Martínez
- Departamento de Biología, Facultad de Química, Av Universidad 3000, Universidad Nacional Autónoma de México (UNAM), Coyoacán, 04510, Distrito Federal, México, Mexico
| | - Luciano Mendoza-Garcés
- Instituto Nacional de Geriatría, Periférico Sur 2767, San Jerónimo Lídice, Magdalena Contreras, 10200, Distrito Federal, México, Mexico
| | - Edgar Vergara-Castañeda
- Departamento de Biología, Facultad de Química, Av Universidad 3000, Universidad Nacional Autónoma de México (UNAM), Coyoacán, 04510, Distrito Federal, México, Mexico
| | - Marco Cerbón
- Departamento de Biología, Facultad de Química, Av Universidad 3000, Universidad Nacional Autónoma de México (UNAM), Coyoacán, 04510, Distrito Federal, México, Mexico.
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30
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Morrison KE, Rodgers AB, Morgan CP, Bale TL. Epigenetic mechanisms in pubertal brain maturation. Neuroscience 2014; 264:17-24. [PMID: 24239720 PMCID: PMC3959229 DOI: 10.1016/j.neuroscience.2013.11.014] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 10/25/2013] [Accepted: 11/06/2013] [Indexed: 01/21/2023]
Abstract
Puberty is a critical period of development during which the reemergence of gonadotropin-releasing hormone secretion from the hypothalamus triggers a cascade of hormone-dependent processes. Maturation of specific brain regions including the prefrontal cortex occurs during this window, but the complex mechanisms underlying these dynamic changes are not well understood. Particularly, the potential involvement of epigenetics in this programming has been under-examined. The epigenome is known to guide earlier stages of development, and it is similarly poised to regulate vital pubertal-driven brain maturation. Further, as epigenetic machinery is highly environmentally responsive, its involvement may also lend this period of growth to greater vulnerability to external insults, resulting in reprogramming and increased disease risk. Importantly, neuropsychiatric diseases commonly present in individuals during or immediately following puberty, and environmental perturbations including stress may precipitate disease onset by disrupting the normal trajectory of pubertal brain development via epigenetic mechanisms. In this review, we discuss epigenetic processes involved in pubertal brain maturation, the potential points of derailment, and the importance of future studies for understanding this dynamic developmental window and gaining a better understanding of neuropsychiatric disease risk.
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Affiliation(s)
- K E Morrison
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, United States.
| | - A B Rodgers
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, United States
| | - C P Morgan
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, United States
| | - T L Bale
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, United States
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31
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Markle JG, Fish EN. SeXX matters in immunity. Trends Immunol 2013; 35:97-104. [PMID: 24239225 DOI: 10.1016/j.it.2013.10.006] [Citation(s) in RCA: 240] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 10/10/2013] [Accepted: 10/14/2013] [Indexed: 11/19/2022]
Abstract
The significant contributions of sex to an immune response, specifically in the context of the sex bias observed in susceptibility to infectious and autoimmune diseases and their pathogenesis, have until recently, largely been ignored and understudied. This review highlights recent findings related to sex-specific factors that provide new insights into how sex determines the transcriptome, the microbiome, and the consequent immune cell functional profile to define an immune response. Unquestionably, accumulating data confirm that sex matters and must be a consideration when decisions around therapeutic intervention strategies are developed.
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Affiliation(s)
- J G Markle
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York NY, 10065, USA
| | - E N Fish
- Toronto General Research Institute, University Health Network, Toronto, Canada; Department of Immunology, University of Toronto, Toronto, Canada.
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32
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Kigar SL, Auger AP. Epigenetic mechanisms may underlie the aetiology of sex differences in mental health risk and resilience. J Neuroendocrinol 2013; 25:1141-50. [PMID: 23841484 PMCID: PMC4428578 DOI: 10.1111/jne.12074] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Revised: 06/26/2013] [Accepted: 07/07/2013] [Indexed: 01/16/2023]
Abstract
In this review, we propose that experiential and hormonal influences on biological sex during development may produce differences in the epigenome, and that these differences play an important role in gating risk or resilience to a number of neurological and psychiatric disorders. One intriguing hypothesis is that the framework belying sex differences in the brain creates differences in methylation and demethylation patterns, and these in turn confer risk and resilience to mental health disorders. Here, we discuss these concepts with regard to social behaviour in rodent models and briefly discuss their possible relevance to human disease.
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Affiliation(s)
- S L Kigar
- Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI, USA
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McCarthy MM, Nugent BM. Epigenetic contributions to hormonally-mediated sexual differentiation of the brain. J Neuroendocrinol 2013; 25:1133-40. [PMID: 23919286 PMCID: PMC5330673 DOI: 10.1111/jne.12072] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 06/18/2013] [Accepted: 06/29/2013] [Indexed: 12/28/2022]
Abstract
It has been long established that hormones exert enduring influences on the developing brain that direct the reproductive response in adulthood, although the cellular mechanisms by which organisational effects are maintained have not been determined satisfactorily. Recent interest in epigenetic modifications to the nervous system has highlighted the potential for hormone-induced changes to the genome that could endure for the lifespan but not be transmitted to the next generation. Preliminary evidence suggests that this is indeed possible because sex differences in the histone code and in the methylation of CpGs in the promoters of specific genes have been identified and, at times, functionally correlated with behaviour. The present review provides an overview of epigenetic processes and discusses the current state-of-the-art, and also identifies future directions.
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Affiliation(s)
- M M McCarthy
- Department of Pharmacology, School of Medicine, University of Maryland, Baltimore, MD, USA
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Permanent and plastic epigenesis in neuroendocrine systems. Front Neuroendocrinol 2013; 34:190-7. [PMID: 23707698 DOI: 10.1016/j.yfrne.2013.05.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 04/26/2013] [Accepted: 05/14/2013] [Indexed: 12/23/2022]
Abstract
The emerging area of neuroepigenetics has been linked to numerous mental health illnesses. Importantly, a large portion of what we know about early gene×environment interactions comes from examining epigenetic modifications of neuroendocrine systems. This review will highlight how neuroepigenetic mechanisms during brain development program lasting differences in neuroendocrine systems and how other neuroepigenetic processes remain plastic, even within the adult brain. As epigenetic mechanisms can either be stable or plastic, elucidating the mechanisms involved in reversing these processes could aid in understanding how to reverse pathological epigenetic programming.
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Mao J, Yuan J, Wang L, Zhang H, Jin X, Zhu J, Li H, Xu B, Chen L. Tamoxifen inhibits migration of estrogen receptor-negative hepatocellular carcinoma cells by blocking the swelling-activated chloride current. J Cell Physiol 2013; 228:991-1001. [PMID: 23042559 DOI: 10.1002/jcp.24245] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 09/26/2012] [Indexed: 02/04/2023]
Abstract
Tamoxifen is a triphenylethylene non-steroidal antiestrogen anticancer agent. It also shows inhibitory effects on metastasis of estrogen receptor (EsR)-independent tumors, but the underlying mechanism is unclear. It was demonstrated in this study that, in EsR-negative and highly metastatic human hepatocellular carcinoma MHCC97H cells, tamoxifen-inhibited cell migration, volume-activated Cl(-) currents (I(Cl,vol)) and regulatory volume decrease (RVD) in a concentration-dependent manner with a similar IC(50). Analysis of the relationships between migration, I(Cl,vol) and RVD showed that cell migration was positively correlated with I(Cl,vol) and RVD. Knockdown of the expression of ClC-3 Cl(-) channel proteins by ClC-3 shRNA or siRNA inhibited I(Cl,vol), and cell migration, and these inhibitory effects could not be increased further by addition of tamoxifen in the medium. The results suggest that knockdown of ClC-3 expression may deplete the effects of tamoxifen; tamoxifen may inhibit cell migration by modulating I(Cl,vol) and cell volume. Moreover, tamoxifen decreased the activity of protein kinase C (PKC) and the effects were reversed by the PKC activator PMA. Activation of PKC by PMA could competitively downregulate the inhibitory effects of tamoxifen on I(Cl,vol). PMA promoted cell migration, and knockdown of ClC-3 expression by ClC-3 siRNA abolished the PMA effect on cell migration. The results suggest that tamoxifen may inhibit I(Cl,vol) by suppressing PKC activation; I(Cl,vol) may be an EsR-independent target for tamoxifen in the anti-metastatic action on cancers, especially on EsR-negative cancers. The finding may have an implication in the clinical use of tamoxifen in the treatments of both EsR-positive and EsR-negative cancers.
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Affiliation(s)
- Jianwen Mao
- Department of Pharmacology and Department of Physiology, Medical College, Jinan University, Guangzhou, China
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Chung WCJ, Auger AP. Gender differences in neurodevelopment and epigenetics. Pflugers Arch 2013; 465:573-84. [PMID: 23503727 DOI: 10.1007/s00424-013-1258-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 02/26/2013] [Accepted: 02/27/2013] [Indexed: 01/19/2023]
Abstract
The concept that the brain differs in make-up between males and females is not new. For example, it is well established that anatomists in the nineteenth century found sex differences in human brain weight. The importance of sex differences in the organization of the brain cannot be overstated as they may directly affect cognitive functions, such as verbal skills and visuospatial tasks in a sex-dependent fashion. Moreover, the incidence of neurological and psychiatric diseases is also highly dependent on sex. These clinical observations reiterate the importance that gender must be taken into account as a relevant possible contributing factor in order to understand the pathogenesis of neurological and psychiatric disorders. Gender-dependent differentiation of the brain has been detected at every level of organization--morphological, neurochemical, and functional--and has been shown to be primarily controlled by sex differences in gonadal steroid hormone levels during perinatal development. In this review, we discuss howthe gonadal steroid hormone testosterone and its metabolites affect downstream signaling cascades, including gonadal steroid receptor activation, and epigenetic events in order to differentiate the brain in a gender-dependent fashion.
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Affiliation(s)
- Wilson C J Chung
- Department of Biological Sciences and School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA.
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Kosten TA, Huang W, Nielsen DA. Sex and litter effects on anxiety and DNA methylation levels of stress and neurotrophin genes in adolescent rats. Dev Psychobiol 2013; 56:392-406. [PMID: 23460384 DOI: 10.1002/dev.21106] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 02/04/2013] [Indexed: 12/12/2022]
Abstract
Maternal care variations associate with DNA methylation of the glucocorticoid receptor gene, Nr3c1, in hippocampus at a nerve-growth factor-inducible protein 1 binding site. Epigenetic regulation of brain-derived neurotrophin factor is affected by early stress. These systems contribute to anxiety and fear. Early stress has sex-dependent effects perhaps reflecting sex differences in maternal care. Altering litter gender composition affects maternal behavior and DNA methylation levels of another gene in hippocampus and nucleus accumbens (NAc). We now test if DNA methylation levels of Nr3c1, Egr1, and Bdnf differ by litter composition or sex. Rats from mixed- or single-sex litters were tested for anxiety and fear on postnatal day 35. Brain tissues were collected and analyzed using direct sequencing methods. Females showed hypermethylation of Nr3c1 of hippocampal DNA and litter composition modified sex effects on methylation of Egr1 in NAc. Few differences were seen for Bdnf. LGC modified some sex differences in behavior.
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Affiliation(s)
- Therese A Kosten
- Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX 77030; Michael E. DeBakey Veteran's Affairs Medical Center, 2002 Holcombe Blvd, Houston, TX 77030.
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Arnold AP, Chen X, Itoh Y. What a difference an X or Y makes: sex chromosomes, gene dose, and epigenetics in sexual differentiation. Handb Exp Pharmacol 2012:67-88. [PMID: 23027446 PMCID: PMC4150872 DOI: 10.1007/978-3-642-30726-3_4] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A modern general theory of sex determination and sexual differentiation identifies the factors that cause sexual bias in gene networks, leading to sex differences in physiology and disease. The primary sex-biasing factors are those encoded on the sex chromosomes that are inherently different in the male and female zygotes. These factors, and downstream factors such as gonadal hormones, act directly on tissues to produce sex differences and antagonize each other to reduce sex differences. Recent studies of mouse models such as the four core genotypes have begun to distinguish between the direct effects of sex chromosome complement (XX vs. XY) and hormonal effects. Several lines of evidence implicate epigenetic processes in the control of sex differences, although a great deal of information is needed about sex differences in the epigenome.
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Affiliation(s)
- Arthur P Arnold
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095, USA.
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Abstract
Type 2 Diabetes Mellitus (T2DM) is a metabolic disorder influenced by interactions between genetic and environmental factors. Epigenetics conveys specific environmental influences into phenotypic traits through a variety of mechanisms that are often installed in early life, then persist in differentiated tissues with the power to modulate the expression of many genes, although undergoing time-dependent alterations. There is still no evidence that epigenetics contributes significantly to the causes or transmission of T2DM from one generation to another, thus, to the current environment-driven epidemics, but it has become so likely, as pointed out in this paper, that one can expect an efflorescence of epigenetic knowledge about T2DM in times to come.
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Larger amygdala but no change in hippocampal volume in 10-year-old children exposed to maternal depressive symptomatology since birth. Proc Natl Acad Sci U S A 2011; 108:14324-9. [PMID: 21844357 DOI: 10.1073/pnas.1105371108] [Citation(s) in RCA: 235] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Maternal separation and poor maternal care in animals have been shown to have important effects on the developing hippocampus and amygdala. In humans, children exposed to abuse/maltreatment or orphanage rearing do not present changes in hippocampal volumes. However, children reared in orphanages present enlarged amygdala volumes, suggesting that the amygdala may be particularly sensitive to severely disturbed (i.e., discontinous, neglectful) care in infancy. Maternal depressive symptomatology has been associated with reductions in overall sensitivity to the infant, and with an increased rate of withdrawn, disengaged behaviors. To determine if poor maternal care associated with maternal depressive symptomatology has a similar pattern of association to the volumes of the hippocampus and amygdala in children, as is the case for severely disturbed infant care (orphanage rearing), we measured hippocampal and amygdala volumes as well as stress hormone (glucocorticoid) levels in children exposed (n = 17) or not (n = 21) to maternal depressive symptomatology since birth. Results revealed no group difference in hippocampal volumes, but larger left and right amygdala volumes and increased levels of glucocorticoids in the children of mothers presenting depressive symptomatology since birth. Moreover, a significant positive correlation was observed between mothers' mean depressive scores and amygdala volumes in their children. The results of this study suggest that amygdala volume in human children may represent an early marker of biological sensitivity to quality of maternal care.
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Protein restriction during pregnancy induces hypertension in adult female rat offspring--influence of oestradiol. Br J Nutr 2011; 107:665-73. [PMID: 21787449 DOI: 10.1017/s0007114511003448] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We previously reported that gestational dietary protein restriction in rats causes sex-related differences in development of blood pressure (BP) in the offspring, which is more pronounced in males than in females. As such effects may depend on sex hormones, we investigated the role of oestradiol in the development of hypertension in female offspring of protein-restricted dams. Female offspring of pregnant rats fed normal (20 %) or protein-restricted (6 %) casein diets throughout pregnancy were kept either intact, ovariectomised or ovariectomised with oestradiol supplementation. BP, Plasma oestradiol and testosterone levels, and vascular oestrogen receptor (ER) were examined. BP was significantly higher and plasma oestradiol levels were significantly lower ( - 34 %) in intact protein-restricted female offspring compared to corresponding controls. Further decrease in oestradiol levels by ovariectomy exacerbated hypertension in the protein-restricted females, with an earlier onset and more prominent elevation in BP compared to controls. Oestradiol supplementation in ovariectomised protein-restricted females significantly reversed ovariectomy-induced hypertension but did not normalise BP to control levels. The hypertensive protein-restricted females have reduced vascular ERα expression that was unaffected by ovariectomy or oestradiol replacement. In addition, testosterone levels were significantly higher by 2·4-, 3·4- and 2·8-fold in intact, ovariectomised and oestradiol-replaced protein-restricted females compared to corresponding controls. The present data show that: (1) hypertension in protein-restricted adult female offspring is associated with reduced plasma oestradiol levels; (2) oestradiol protects and limits the severity of hypertension in protein-restricted females and contributes to sexual dimorphism; (3) oestradiol replacement fails to completely reverse hypertension, which may be related to limited availability of vascular ERα receptors and/or increased circulating testosterone levels.
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Jessen HM, Auger AP. Sex differences in epigenetic mechanisms may underlie risk and resilience for mental health disorders. Epigenetics 2011; 6:857-61. [PMID: 21617370 DOI: 10.4161/epi.6.7.16517] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Alterations in the epigenetic programming of sex differences in the brain may underlie sexually dimorphic neurodevelopmental disorders. Sex differences have been found in DNA methyltransferases 3a, DNA methylation patterns, MeCP2, and nuclear corepressor within the developing brain. Natural variations in these epigenetic mechanisms have profound consequences on gene expression and brain function. Exogenous or endogenous perturbations during development may impact these epigenetic processes and alter the trajectory of the developing brain and confer sexually dimorphic risk and resilience for developing a neurological or mental health disorder.
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Affiliation(s)
- Heather M Jessen
- Department of Psychology, University of Wisconsin, Madison, Madison, WI, USA
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