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David CD, Wyrosdic BN, Wan H, Lapp HE, Bartlett AA, Yitbarek S, Park JH. B6D2F1 mice that retain sexual behavior long term after castration outperform those that cease in the radial arm maze. Psychoneuroendocrinology 2022; 136:105627. [PMID: 34923212 DOI: 10.1016/j.psyneuen.2021.105627] [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] [Received: 05/07/2021] [Revised: 12/07/2021] [Accepted: 12/09/2021] [Indexed: 11/25/2022]
Abstract
In rodents, gonadal steroids play a critical yet variable role in behaviors such as social interaction and cognitive performance. Gonadal steroids organize sex differences observed in spatial working memory, while the absence of activational effects induced by castration generally impedes spatial learning and memory. Although male sexual behavior is typically inhibited following castration, a significant proportion of gonadectomized B6D2F1 hybrid males retains the complete repertoire of male reproductive behavior. In a prior study, amyloid precursor protein and tau, proteins involved in cognitive behavior, facilitated steroid-independent male sex behavior in B6D2F1 hybrid male mice. We used this strain to investigate the relationship between gonadal steroid-independent male sexual behavior and cognition. After identifying "maters" (animals retaining steroid-independent male sex behavior) and "non-maters," we tested spatial memory in an 8-arm radial arm maze. Although neither group demonstrated a decrease in errors as a function of time, maters committed fewer errors compared to non-maters overall (p < 0.05). Maters also completed the maze more quickly than non-maters (p < 0.05). We measured mRNA expression of APP and MAPT as well as LEPR and D2R to probe potential roles of metabolism and motivation. Uniquely among maters, increased relative expression of D2R and LEPR in the hippocampus was associated with a longer latency to complete the maze during the last 3 or across all trials, respectively. These data demonstrate that maters outperform non-maters in the radial arm maze, warranting further study of potential differences in acquisition of spatial memory tasks or learning strategy between these groups.
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Affiliation(s)
- Caroline D David
- Department of Psychology, University of Massachusetts Boston, Boston, MA 02125, USA.
| | - Brianna N Wyrosdic
- Department of Psychology, University of Massachusetts Boston, Boston, MA 02125, USA
| | - HoYin Wan
- Department of Psychology, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Hannah E Lapp
- Department of Psychology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Andrew A Bartlett
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA 02478, USA
| | - Shewit Yitbarek
- Department of Psychology, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Jin Ho Park
- Department of Psychology, University of Massachusetts Boston, Boston, MA 02125, USA
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2
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Gadomsky L, Dos Santos Guilherme M, Winkler J, van der Kooij MA, Hartmann T, Grimm M, Endres K. Elevated Testosterone Level and Urine Scent Marking in Male 5xFAD Alzheimer Model Mice. Curr Alzheimer Res 2021; 17:80-92. [PMID: 32065104 DOI: 10.2174/1567205017666200217105537] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 01/13/2020] [Accepted: 01/20/2020] [Indexed: 12/27/2022]
Abstract
BACKGROUND Function of the Amyloid Precursor Protein (AβPP) and its various cleavage products still is not unraveled down to the last detail. While its role as a source of the neurotoxic Amyloid beta (Aβ) peptides in Alzheimer's Disease (AD) is undisputed and its property as a cell attachment protein is intriguing, while functions outside the neuronal context are scarcely investigated. This is particularly noteworthy because AβPP has a ubiquitous expression profile and its longer isoforms, AβPP750 and 770, are found in various tissues outside the brain and in non-neuronal cells. OBJECTIVE Here, we aimed at analyzing the 5xFAD Alzheimer's disease mouse model in regard to male sexual function. The transgenes of this mouse model are regulated by Thy1 promoter activity and Thy1 is expressed in testes, e.g. by Sertoli cells. This allows speculation about an influence on sexual behavior. METHODS We analyzed morphological as well as biochemical properties of testicular tissue from 5xFAD mice and wild type littermates and testosterone levels in serum, testes and the brain. Sexual behavior was assessed by a urine scent marking test at different ages for both groups. RESULTS While sperm number, testes weight and morphological phenotypes of sperms were nearly indistinguishable from those of wild type littermates, testicular testosterone levels were significantly increased in the AD model mice. This was accompanied by elevated and prolonged sexual interest as displayed within the urine scent marking test. CONCLUSION We suggest that overexpression of AβPP, which mostly is used to mimic AD in model mice, also affects male sexual behavior as assessed additional by the Urine Scent Marking (USM) test. The elevated testosterone levels might have an additional impact on central nervous system androgen receptors and also have to be considered when assessing learning and memory capabilities.
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Affiliation(s)
- Lisa Gadomsky
- Department of Psychiatry and Psychotherapy, University Medical Center Johannes Gutenberg- University, Mainz, Germany
| | - Malena Dos Santos Guilherme
- Department of Psychiatry and Psychotherapy, University Medical Center Johannes Gutenberg- University, Mainz, Germany
| | - Jakob Winkler
- German Institute for Dementia Prevention (GIDP), Neurodegeneration and Neurobiology, Saarland University, Homburg/Saar, Germany and Experimental Neurology, Saarland University, Homburg/Saar, Germany
| | - Michael A van der Kooij
- Department of Psychiatry and Psychotherapy, University Medical Center Johannes Gutenberg- University, Mainz, Germany
| | - Tobias Hartmann
- German Institute for Dementia Prevention (GIDP), Neurodegeneration and Neurobiology, Saarland University, Homburg/Saar, Germany and Experimental Neurology, Saarland University, Homburg/Saar, Germany
| | - Marcus Grimm
- German Institute for Dementia Prevention (GIDP), Neurodegeneration and Neurobiology, Saarland University, Homburg/Saar, Germany and Experimental Neurology, Saarland University, Homburg/Saar, Germany
| | - Kristina Endres
- Department of Psychiatry and Psychotherapy, University Medical Center Johannes Gutenberg- University, Mainz, Germany
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3
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Chiang VSC, Park JH. Glutamate in Male and Female Sexual Behavior: Receptors, Transporters, and Steroid Independence. Front Behav Neurosci 2020; 14:589882. [PMID: 33328921 PMCID: PMC7732465 DOI: 10.3389/fnbeh.2020.589882] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/20/2020] [Indexed: 01/12/2023] Open
Abstract
The survival of animal species predicates on the success of sexual reproduction. Neurotransmitters play an integral role in the expression of these sexual behaviors in the brain. Here, we review the role of glutamate in sexual behavior in rodents and non-rodent species for both males and females. These encompass the release of glutamate and correlations with glutamate receptor expression during sexual behavior. We then present the effects of glutamate on sexual behavior, as well as the effects of antagonists and agonists on different glutamate transporters and receptors. Following that, we discuss the potential role of glutamate on steroid-independent sexual behavior. Finally, we demonstrate the interaction of glutamate with other neurotransmitters to impact sexual behavior. These sexual behavior studies are crucial in the development of novel treatments of sexual dysfunction and in furthering our understanding of the complexity of sexual diversity. In the past decade, we have witnessed the burgeoning of novel techniques to study and manipulate neuron activity, to decode molecular events at the single-cell level, and to analyze behavioral data. They pose exciting avenues to gain further insight into future sexual behavior research. Taken together, this work conveys the essential role of glutamate in sexual behavior.
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Affiliation(s)
- Vic Shao-Chih Chiang
- Developmental and Brain Sciences, Department of Psychology, University of Massachusetts Boston, Boston, MA, United States
| | - Jin Ho Park
- Developmental and Brain Sciences, Department of Psychology, University of Massachusetts Boston, Boston, MA, United States
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4
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Xiao S, Song LL, Li JT, Wang H, Yu N, Wang ZQ, Zhang Y, He JS, Hung T. Intraperitoneal Administration of Monoclonal Antibody Against Pathologic Aβ42 Aggregates Alleviated Cognitive Deficits and Synaptic Lesions in APP/PS1 Mice. J Alzheimers Dis 2020; 73:657-670. [PMID: 31839610 DOI: 10.3233/jad-190874] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia, characterized by amyloid-β peptide (Aβ) aggregates, phosphorylated tau protein (p-tau), and progressive neurodegeneration. Amyloid-β peptide 42 (Aβ42) is considered an early trigger of AD pathogenesis. We have previously reported that Aβ N-terminus monoclonal antibody (mAb) A8 alleviated cognitive dysfunction and reduced the abundance of soluble Aβ in the brains of the senescence-accelerated mouse prone 8 (SAMP8) mouse model. To confirm the efficacy of mAb A8 in the double-transgenic APPswe/PS1ΔE9 (APP/PS1) mice, here we reported the related findings. The Morris water maze (MWM) data showed that the A8 treatment group had a shorter escape latency than the control groups in the place navigation test and the probe trial (p < 0.05). Moreover, immunohistochemistry showed decreased levels of both Aβ and p-tau in the brains of APP/PS1 mice. Regarding Aβ levels, western blot results showed that Aβ42 oligomer (p < 0.01) but not Aβ40 levels were diminished in brains of A8-treated APP/PS1 mice. Western blot results showed that phospho-tau (pSer231) (p < 0.01) but not tau levels were reduced in A8-treated mouse brains. Furthermore, transmission electron microscopy images indicated ultrastructural improvements, including an increased (p < 0.01) density of synapses and a reduction of abnormally enlarged mitochondria (p < 0.01), in the brains of A8-treated mice. Taken together, our data showed that mAb A8 is highly efficacious in APP/PS1 mice as a treatment for AD, and the underlying mechanism may target synaptic pathology by inhibiting the amyloid cascade.
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Affiliation(s)
- Shuo Xiao
- College of Life Sciences and Bioengineering, Beijing Jiaotong University, Beijing, China
| | - Lin-Lin Song
- College of Life Sciences and Bioengineering, Beijing Jiaotong University, Beijing, China
| | - Jiang-Tao Li
- College of Life Sciences and Bioengineering, Beijing Jiaotong University, Beijing, China
| | - He Wang
- College of Life Sciences and Bioengineering, Beijing Jiaotong University, Beijing, China
| | - Na Yu
- College of Life Sciences and Bioengineering, Beijing Jiaotong University, Beijing, China
| | - Zi-Qi Wang
- College of Life Sciences and Bioengineering, Beijing Jiaotong University, Beijing, China
| | - Ying Zhang
- College of Life Sciences and Bioengineering, Beijing Jiaotong University, Beijing, China
| | - Jin-Sheng He
- College of Life Sciences and Bioengineering, Beijing Jiaotong University, Beijing, China
| | - Tao Hung
- College of Life Sciences and Bioengineering, Beijing Jiaotong University, Beijing, China.,Institute for Viral Disease Control and Prevention, China CDC, Beijing, China
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5
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Duthie CJ, Calich HJ, Rapsey CM, Wibowo E. Maintenance of sexual activity following androgen deprivation in males. Crit Rev Oncol Hematol 2020; 153:103064. [DOI: 10.1016/j.critrevonc.2020.103064] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 05/12/2020] [Accepted: 07/12/2020] [Indexed: 01/14/2023] Open
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6
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Templin JS, Wyrosdic JC, David CD, Wyrosdic BN, Lapp HE, Bala A, Bartlett A, Khan Z, Rokicki A, Park JH. Peripubertal gonadal steroids are necessary for steroid-independent male sexual behavior in castrated B6D2F1 male mice. Horm Behav 2019; 113:38-46. [PMID: 31047887 DOI: 10.1016/j.yhbeh.2019.04.013] [Citation(s) in RCA: 4] [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: 07/26/2018] [Revised: 04/14/2019] [Accepted: 04/27/2019] [Indexed: 11/23/2022]
Abstract
Gonadal steroids play an integral role in male sexual behavior, and in most rodent models, this relationship is tightly coupled. However, many other species, including humans, continue to demonstrate male sex behavior in the absence of gonadal steroids, and the mechanisms that regulate steroid-independent male sex behavior are not well understood. Approximately 30% of castrated male B6D2F1 hybrid mice display male sex behavior many months after castration, allowing for the investigation of individual variation in steroidal regulation of male sex behavior. During both the perinatal and peripubertal periods of development, the organizational effects of gonadal steroids on sexual differentiation of the neural circuits controlling male sex behavior are well-documented. Several factors can alter the normal range of gonadal steroids or their receptors which may lead to the disruption of the normal processes of masculinization and defeminization. It is unknown whether the organizational effects of gonadal hormones during puberty are necessary for steroid-independent male sex behavior. However, gonadal steroids during puberty were not necessary for either testosterone or estradiol to activate male sex behavior in adulthood. Furthermore, activation of male sex behavior was initiated sooner in hybrid male mice castrated prior to puberty that were administered estradiol in adulthood compared to those that were provided testosterone. The underlying mechanisms by which gonadal hormones, during both the perinatal and peripubertal developmental periods of sexual differentiation, organize the normal maturation of neural circuitry that regulates steroid-independent male sex behavior in adult castrated B6D2F1 male mice warrants further investigation.
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Affiliation(s)
- Jay Scott Templin
- Psychology Department, University of Massachusetts Boston, Boston, MA 02125, United States of America.
| | - Joshua C Wyrosdic
- Psychology Department, University of Massachusetts Boston, Boston, MA 02125, United States of America; Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, 1650 Cedar Avenue, Montreal H3G 1A4, Canada
| | - Caroline D David
- Psychology Department, University of Massachusetts Boston, Boston, MA 02125, United States of America
| | - Brianna N Wyrosdic
- Psychology Department, University of Massachusetts Boston, Boston, MA 02125, United States of America
| | - Hannah E Lapp
- Psychology Department, University of Massachusetts Boston, Boston, MA 02125, United States of America
| | - Andis Bala
- Psychology Department, University of Massachusetts Boston, Boston, MA 02125, United States of America
| | - Alexander Bartlett
- Psychology Department, University of Massachusetts Boston, Boston, MA 02125, United States of America
| | - Zara Khan
- Psychology Department, University of Massachusetts Boston, Boston, MA 02125, United States of America
| | - Alicia Rokicki
- Psychology Department, University of Massachusetts Boston, Boston, MA 02125, United States of America
| | - Jin Ho Park
- Psychology Department, University of Massachusetts Boston, Boston, MA 02125, United States of America
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7
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Pfaff DW, Baum MJ. Hormone-dependent medial preoptic/lumbar spinal cord/autonomic coordination supporting male sexual behaviors. Mol Cell Endocrinol 2018; 467:21-30. [PMID: 29100889 DOI: 10.1016/j.mce.2017.10.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 10/19/2017] [Accepted: 10/30/2017] [Indexed: 11/19/2022]
Abstract
Testosterone (T) can act directly through neural androgen receptors (AR) to facilitate male sexual behavior; however, T's metabolites also can play complicated and interesting roles in the control of mating. One metabolite, dihydrotestosterone (DHT) binds to AR with significantly greater affinity than that of T. Is that important behaviorally? Another metabolite, estradiol (E), offers a potential alternative route of facilitating male mating behavior by acting through estradiol receptors (ER). In this review we explore the roles and relative importance of T as well as E and DHT at various levels of the neuroaxis for the activation of male sex behavior in common laboratory animals and, when relevant research findings are available, in man.
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Affiliation(s)
- Donald W Pfaff
- Laboratory of Neurobiology and Behavior, The Rockefeller University, New York, NY 10065, United States.
| | - Michael J Baum
- Department of Biology, Boston University, Boston, MA 02215, United States
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8
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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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9
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McInnis CM, Venu S, Park JH. Steroid-independent male sexual behavior in B6D2F2 male mice. Horm Behav 2016; 85:26-29. [PMID: 27476435 DOI: 10.1016/j.yhbeh.2016.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 07/19/2016] [Accepted: 07/27/2016] [Indexed: 11/16/2022]
Abstract
It is well established that male sexual behavior (MSB) is regulated by gonadal steroids; however, individual differences in MSB, independent of gonadal steroids, are prevalent across a wide range of species, and further investigation is necessary to advance our understanding of steroid-independent MSB. Studies utilizing B6D2F1 hybrid male mice in which a significant proportion retain MSB after long-term orchidectomy, identified as steroid-independent-maters (SI-maters), have begun to unravel the genetic underpinnings of steroid-independent MSB. A recent study demonstrated that steroid-independent MSB is a heritable behavioral phenotype that is mainly passed down from B6D2F1 hybrid SI-maters when crossed with C57BL6J female mice. To begin to uncover whether the strain of the dam plays a role in the inheritance of steroid-independent MSB, B6D2F1 hybrid females were crossed with B6D2F1 hybrid males. While the present study confirms the finding that steroid-independent MSB is a heritable behavioral phenotype and that SI-mater sires are more likely to pass down some components of MSB than SI-non-maters to their offspring, it also reveals that the B6D2F2 male offspring that were identified as SI-maters that displayed the full repertoire of steroid-independent MSB had the same probability of being sired from either a B6D2F1 SI-mater or SI-non-mater. These results, in conjunction with previous findings, indicate that the specific chromosomal loci pattern that codes for steroid-independent MSB in the B6D2F2 male offspring may result regardless of whether the father was a SI-mater or SI-non-mater, and that the maternal strain may be an important factor in the inheritance of steroid-independent MSB.
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Affiliation(s)
- Christine M McInnis
- Psychology Department, University of Massachusetts, Boston, Boston, MA 02125, United States.
| | - Samitha Venu
- Psychology Department, University of Massachusetts, Boston, Boston, MA 02125, United States
| | - Jin Ho Park
- Psychology Department, University of Massachusetts, Boston, Boston, MA 02125, United States
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10
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McInnis CM, Bonthuis PJ, Rissman EF, Park JH. Inheritance of steroid-independent male sexual behavior in male offspring of B6D2F1 mice. Horm Behav 2016; 80:132-138. [PMID: 26940434 PMCID: PMC4818728 DOI: 10.1016/j.yhbeh.2016.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 02/23/2016] [Accepted: 02/24/2016] [Indexed: 01/28/2023]
Abstract
The importance of gonadal steroids in modulating male sexual behavior is well established. Individual differences in male sexual behavior, independent of gonadal steroids, are prevalent across a wide range of species, including man. However, the genetic mechanisms underlying steroid-independent male sexual behavior are poorly understood. A high proportion of B6D2F1 hybrid male mice demonstrates steroid-independent male sexual behavior (identified as "maters"), providing a mouse model that opens up avenues of investigation into the mechanisms regulating male sexual behavior in the absence of gonadal hormones. Recent studies have revealed several proteins that play a significant factor in regulating steroid-independent male sexual behavior in B6D2F1 male mice, including amyloid precursor protein (APP), tau, and synaptophysin. The specific goals of our study were to determine whether steroid-independent male sexual behavior was a heritable trait by determining if it was dependent upon the behavioral phenotype of the B6D2F1 sire, and whether the differential expression of APP, tau, and synaptophysin in the medial preoptic area found in the B6D2F1 sires that did and did not mate after gonadectomy was similar to those found in their male offspring. After adult B6D2F1 male mice were bred with C57BL/6J female mice, they and their male offspring (BXB1) were orchidectomized and identified as either maters or "non-maters". A significant proportion of the BXB1 maters was sired only from B6D2F1 maters, indicating that the steroid-independent male sexual behavior behavioral phenotype of the B6D2F1 hybrid males, when crossed with C57BL/6J female mice, is inherited by their male offspring. Additionally, APP, tau, and synaptophysin were elevated in in the medial preoptic area in both the B6D2F1 and BXB1 maters relative to the B6D2F1 and BXB1 non-maters, respectively, suggesting a potential genetic mechanism for the inheritance of steroid-independent male sexual behavior.
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Affiliation(s)
- Christine M McInnis
- Psychology Department, University of Massachusetts, Boston, Boston, MA 02125, United States.
| | - Paul J Bonthuis
- Department of Biochemistry & Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, United States
| | - Emilie F Rissman
- Department of Biochemistry & Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, United States
| | - Jin Ho Park
- Psychology Department, University of Massachusetts, Boston, Boston, MA 02125, United States; Department of Biochemistry & Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, United States
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11
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Schaafsma SM, Pfaff DW. Etiologies underlying sex differences in Autism Spectrum Disorders. Front Neuroendocrinol 2014; 35:255-71. [PMID: 24705124 DOI: 10.1016/j.yfrne.2014.03.006] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 02/06/2014] [Accepted: 03/17/2014] [Indexed: 01/09/2023]
Abstract
The male predominance of Autism Spectrum Disorders (ASD) is one of the best-known, and at the same time, one of the least understood characteristics of these disorders. In this paper we review genetic, epigenetic, hormonal, and environmental mechanisms underlying this male preponderance. Sex-specific effects of Y-linked genes (including SRY expression leading to testicular development), balanced and skewed X-inactivation, genes that escape X-inactivation, parent-of-origin allelic imprinting, and the hypothetical heterochromatin sink are reviewed. These mechanisms likely contribute to etiology, instead of being simply causative to ASD. Environments, both internal and external, also play important roles in ASD's etiology. Early exposure to androgenic hormones and early maternal immune activation comprise environmental factors affecting sex-specific susceptibility to ASD. The gene-environment interactions underlying ASD, suggested here, implicate early prenatal stress as being especially detrimental to boys with a vulnerable genotype.
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Affiliation(s)
- Sara M Schaafsma
- Laboratory of Neurobiology and Behavior, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
| | - Donald W Pfaff
- Laboratory of Neurobiology and Behavior, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
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12
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Bharadwaj P, McInnis C, Madden AMK, Bonthuis PJ, Zup S, Rissman EF, Park JH. Increased dendritic spine density and tau expression are associated with individual differences in steroidal regulation of male sexual behavior. PLoS One 2013; 8:e69672. [PMID: 23874981 PMCID: PMC3713039 DOI: 10.1371/journal.pone.0069672] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 06/11/2013] [Indexed: 11/19/2022] Open
Abstract
Male sexual behavior (MSB) is modulated by gonadal steroids, yet this relationship is highly variable across species and between individuals. A significant percentage (~30%) of B6D2F1 hybrid male mice demonstrate MSB after long-term orchidectomy (herein after referred to as "maters"), providing an opportunity to examine the mechanisms that underlie individual differences in steroidal regulation of MSB. Use of gene expression arrays comparing maters and non-maters has provided a first pass look at the genetic underpinnings of steroid-independent MSB. Surprisingly, of the ~500 genes in the medial preoptic area (MPOA) that differed between maters and non-maters, no steroid hormone or receptor genes were differentially expressed between the two groups. Interestingly, best known for their association with Alzheimer's disease, amyloid precursor protein (APP) and the microtubule-associated protein tau (MAPT) were elevated in maters. Increased levels of their protein products (APP and tau) in their non-pathological states have been implicated in cell survival, neuroprotection, and supporting synaptic integrity. Here we tested transgenic mice that overexpress tau and found facilitated mounting and intromission behavior after long-term orchidectomy relative to littermate controls. In addition, levels of synaptophysin and spinophilin, proteins generally enriched in synapses and dendritic spines respectively, were elevated in the MPOA of maters. Dendritic morphology was also assessed in Golgi-impregnated brains of orchidectomized B6D2F1 males, and hybrid maters exhibited greater dendritic spine density in MPOA neurons. In sum, we show for the first time that retention of MSB in the absence of steroids is correlated with morphological differences in neurons.
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Affiliation(s)
- Pranay Bharadwaj
- Psychology Department, University of Massachusetts, Boston, Boston, Massachusetts, United States of America
| | - Christine McInnis
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Amanda M. K. Madden
- Psychology Department, University of Massachusetts, Boston, Boston, Massachusetts, United States of America
| | - Paul J. Bonthuis
- Department of Neurobiology and Anatomy, University of Utah, School of Medicine, Salt Lake City, Utah, United States of America
| | - Susan Zup
- Psychology Department, University of Massachusetts, Boston, Boston, Massachusetts, United States of America
| | - Emilie F. Rissman
- Department of Biochemistry & Molecular Genetics, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
| | - Jin Ho Park
- Psychology Department, University of Massachusetts, Boston, Boston, Massachusetts, United States of America
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13
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Abstract
Brain sexual differentiation in rodents results from the perinatal testicular androgen surge. In the preoptic area (POA), estradiol aromatized from testosterone upregulates the production of the proinflammatory molecule, prostaglandin E(2) (PGE(2)) to produce sex-specific brain development. PGE(2) produces a two-fold greater density of dendritic spines in males than in females and masculinizes adult copulatory behavior. One neonatal dose of PGE(2) masculinizes the POA and behavior, and simultaneous treatment with an inhibitor of additional prostaglandin synthesis prevents this masculinization, indicating a positive feedforward process that leads to sustained increases in PGE(2). The mechanisms underlying this feedforward process were unknown. Microglia, the primary immunocompetent cells in the brain, are active neonatally, contribute to normal brain development, and both produce and respond to prostaglandins. We investigated whether there are sex differences in microglia in the POA and whether they influence developmental masculinization. Neonatal males had twice as many ameboid microglia as females and a more activated morphological profile, and both estradiol and PGE(2) masculinized microglial number and morphology in females. Microglial inhibition during the critical period for sexual differentiation prevented sex differences in microglia, estradiol-induced masculinization of dendritic spine density, and adult copulatory behavior. Microglial inhibition also prevented the estradiol-induced upregulation of PGE(2), indicating that microglia are essential to the feedforward process through which estradiol upregulates prostaglandin production. These studies demonstrate that immune cells in the brain interact with the nervous and endocrine systems during development, and are crucial for sexual differentiation of brain and behavior.
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Nam Y, Shin EJ, Yang BK, Bach JH, Jeong JH, Chung YH, Park ES, Li Z, Kim KW, Kwon YB, Nabeshima T, Kim HC. Dextromethorphan-induced psychotoxic behaviors cause sexual dysfunction in male mice via stimulation of σ-1 receptors. Neurochem Int 2012; 61:913-22. [PMID: 22326744 DOI: 10.1016/j.neuint.2012.01.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 01/15/2012] [Accepted: 01/23/2012] [Indexed: 11/15/2022]
Abstract
Dextromethorphan (DM) is a well-known antitussive dextrorotatory morphinan. We and others have demonstrated that sigma (σ) receptors may be important for DM-mediated neuromodulation. Because an earlier report suggested that DM might affect sexual function and that σ receptor ligands affect signaling pathways in the periphery, we examined whether DM-induced psychotoxic burden affected male reproductive function. We observed that DM had a high affinity at σ-1 receptors in the brain and testis but relatively low affinity at σ-2 receptors. Prolonged treatment with DM resulted in conditioned place preference and hyperlocomotion, followed by an increase in Fos-related antigen expression in the nucleus accumbens in male mice. Simultaneously, DM induced significant reductions in gonadotropin-releasing-hormone immunoreactivity in the hypothalamus. Moreover, we observed that DM induced increased sperm abnormalities and decreased sperm viability and sexual behavior. These phenomena were significantly attenuated by combined treatment with BD1047, a σ-1 receptor antagonist, but not by SM-21, a σ-2 receptor antagonist. Thus, these results suggest that DM psychotoxicity might lead to reproductive stress in male mice by activating σ-1 receptors.
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Affiliation(s)
- Yunsung Nam
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul 156-756, Republic of Korea
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15
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Lenz KM, Nugent BM, McCarthy MM. Sexual differentiation of the rodent brain: dogma and beyond. Front Neurosci 2012; 6:26. [PMID: 22363256 PMCID: PMC3282918 DOI: 10.3389/fnins.2012.00026] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 02/04/2012] [Indexed: 11/20/2022] Open
Abstract
Steroid hormones of gonadal origin act on the neonatal brain to produce sex differences that underlie adult reproductive physiology and behavior. Neuronal sex differences occur on a variety of levels, including differences in regional volume and/or cell number, morphology, physiology, molecular signaling, and gene expression. In the rodent, many of these sex differences are determined by steroid hormones, particularly estradiol, and are established by diverse downstream effects. One brain region that is potently organized by estradiol is the preoptic area (POA), a region critically involved in many behaviors that show sex differences, including copulatory and maternal behaviors. This review focuses on the POA as a case study exemplifying the depth and breadth of our knowledge as well as the gaps in understanding the mechanisms through which gonadal hormones produce lasting neural and behavioral sex differences. In the POA, multiple cell types, including neurons, astrocytes, and microglia are masculinized by estradiol. Multiple downstream molecular mediators are involved, including prostaglandins, various glutamate receptors, protein kinase A, and several immune signaling molecules. Moreover, emerging evidence indicates epigenetic mechanisms maintain sex differences in the POA that are organized perinatally and thereby produce permanent behavioral changes. We also review emerging strategies to better elucidate the mechanisms through which genetics and epigenetics contribute to brain and behavioral sex differences.
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Affiliation(s)
- Kathryn M Lenz
- Program in Neuroscience and Department of Physiology, University of Maryland School of Medicine Baltimore, MD, USA
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16
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Piekarski DJ, Seto T, Zucker I. The protein synthesis inhibitor anisomycin reduces sex behavior during a critical period after testosterone treatment in male Syrian hamsters. Physiol Behav 2011; 105:215-9. [PMID: 21896280 DOI: 10.1016/j.physbeh.2011.08.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 08/20/2011] [Accepted: 08/23/2011] [Indexed: 11/25/2022]
Abstract
Testosterone (T) is critical for maintaining male sexual behavior (MSB) in rodents, in part by altering protein synthesis in a well-defined neural circuit. The specific timing of protein synthesis essential for expression of MSB has never been investigated. We administered the protein synthesis inhibitor anisomycin (Ani) to castrated male Syrian hamsters treated sc with 100 μg T in an aqueous vehicle once weekly; this T regimen maintains MSB while elevating circulating T concentrations for only a few hours after each injection. Hamsters were injected s.c. with the vehicle or 12.5 mg Ani at one of several times relative to T administration; MSB was assessed once per week, 6 days after the previous T injection, for 5 weeks. Anisomycin administered 6-12 h after T injection significantly reduced the expression of sexual behavior, whereas Ani treatment between 3 h before and 3 h after T injection did not impair MSB. This experiment is the first to assess the specific timing of protein synthesis relative to a T pulse that is required for the expression of MSB. The demarcation of a critical interval for T-induced protein synthesis necessary for maintenance of MSB should facilitate specification of the genomic, proteomic, and biochemical cascades that subserve actions of T on male copulation.
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Affiliation(s)
- David J Piekarski
- Department of Psychology, University of California, Berkeley, Berkeley, CA 94720, USA.
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17
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Abstract
In the twentieth century, the dominant model of sexual differentiation stated that genetic sex (XX versus XY) causes differentiation of the gonads, which then secrete gonadal hormones that act directly on tissues to induce sex differences in function. This serial model of sexual differentiation was simple, unifying and seductive. Recent evidence, however, indicates that the linear model is incorrect and that sex differences arise in response to diverse sex-specific signals originating from inherent differences in the genome and involve cellular mechanisms that are specific to individual tissues or brain regions. Moreover, sex-specific effects of the environment reciprocally affect biology, sometimes profoundly, and must therefore be integrated into a realistic model of sexual differentiation. A more appropriate model is a parallel-interactive model that encompasses the roles of multiple molecular signals and pathways that differentiate males and females, including synergistic and compensatory interactions among pathways and an important role for the environment.
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Affiliation(s)
- Margaret M McCarthy
- Departments of Physiology and Psychiatry and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland, USA.
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18
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Wesson DW, Nixon RA, Levy E, Wilson DA. Mechanisms of neural and behavioral dysfunction in Alzheimer's disease. Mol Neurobiol 2011; 43:163-79. [PMID: 21424679 DOI: 10.1007/s12035-011-8177-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Accepted: 03/03/2011] [Indexed: 10/18/2022]
Abstract
This review critically examines progress in understanding the link between Alzheimer's disease (AD) molecular pathogenesis and behavior, with an emphasis on the impact of amyloid-β. We present the argument that the AD research field requires more multifaceted analyses into the impacts of Alzheimer's pathogenesis which combine simultaneous molecular-, circuit-, and behavior-level approaches. Supporting this argument is a review of particular research utilizing similar, "systems-level" methods in mouse models of AD. Related to this, a critique of common physiological and behavioral models is made-highlighting the likely usefulness of more refined and specific tools in understanding the relationship between candidate molecular pathologies and behavioral dysfunction. Finally, we propose challenges for future research which, if met, may greatly extend our current understanding of how AD molecular pathology impacts neural network function and behavior and possibly may lead to refinements in disease therapeutics.
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Affiliation(s)
- Daniel W Wesson
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research, New York University School of Medicine, Orangeburg, NY 10962, USA.
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19
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Qureshi IA, Mehler MF. Genetic and epigenetic underpinnings of sex differences in the brain and in neurological and psychiatric disease susceptibility. PROGRESS IN BRAIN RESEARCH 2010; 186:77-95. [PMID: 21094887 PMCID: PMC4465286 DOI: 10.1016/b978-0-444-53630-3.00006-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
There are numerous examples of sex differences in brain and behavior and in susceptibility to a broad range of brain diseases. For example, gene expression is sexually dimorphic during brain development, adult life, and aging. These differences are orchestrated by the interplay between genetic, hormonal, and environmental influences. However, the molecular mechanisms that underpin these differences have not been fully elucidated. Because recent studies have highlighted the key roles played by epigenetic processes in regulating gene expression and mediating brain form and function, this chapter reviews emerging evidence that shows how epigenetic mechanisms including DNA methylation, histone modifications, and chromatin remodeling, and non-coding RNAs (ncRNAs) are responsible for promoting sexual dimorphism in the brain. Differential profiles of DNA methylation and histone modifications are found in dimorphic brain regions such as the hypothalamus as a result of sex hormone exposure during developmental critical periods. The elaboration of specific epigenetic marks is also linked with regulating sex hormone signaling pathways later in life. Furthermore, the expression and function of epigenetic factors such as the methyl-CpG-binding protein, MeCP2, and the histone-modifying enzymes, UTX and UTY, are sexually dimorphic in the brain. ncRNAs are also implicated in promoting sex differences. For example, X inactivation-specific transcript (XIST) is a long ncRNA that mediates X chromosome inactivation, a seminal developmental process that is particularly important in brain. These observations imply that understanding epigenetic mechanisms, which regulate dimorphic gene expression and function, is necessary for developing a more comprehensive view of sex differences in brain. These emerging findings also suggest that epigenetic mechanisms are, in part, responsible for the differential susceptibility between males and females that is characteristic of a spectrum of neurological and psychiatric disorders.
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Affiliation(s)
- Irfan A. Qureshi
- Rosyln and Leslie Goldstein Laboratory for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
- Institute for Brain Disorders and Neural Regeneration, Albert Einstein College of Medicine, Bronx, NY, USA
- Departments of Neurology, Albert Einstein College of Medicine, Bronx, NY, USA
- Rose F. Kennedy Center for Research on Intellectual and Developmental Disabilities, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Mark F. Mehler
- Rosyln and Leslie Goldstein Laboratory for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
- Institute for Brain Disorders and Neural Regeneration, Albert Einstein College of Medicine, Bronx, NY, USA
- Departments of Neurology, Albert Einstein College of Medicine, Bronx, NY, USA
- Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
- Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, NY, USA
- Rose F. Kennedy Center for Research on Intellectual and Developmental Disabilities, Albert Einstein College of Medicine, Bronx, NY, USA
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