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Harshaw C, Warner AG. Interleukin-1β-induced inflammation and acetaminophen during infancy: Distinct and interactive effects on social-emotional and repetitive behavior in C57BL/6J mice. Pharmacol Biochem Behav 2022; 220:173463. [PMID: 36100070 DOI: 10.1016/j.pbb.2022.173463] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 08/28/2022] [Accepted: 09/05/2022] [Indexed: 11/19/2022]
Abstract
Acetaminophen (APAP) exposure early in life has been associated with increased risk of neurodevelopmental disorders in epidemiological studies. In rodent models, early-life APAP has similarly been shown to produce long-term changes in brain and behavior, including altered activity levels and social behavior. Most rodent studies to date have, nevertheless, attempted to model early-life APAP without considering that most APAP exposure occurs in a context of immune activation and/or fever. To mimic the repeated infections common during infancy, we employed the cytokine interleukin-1β (IL-1β) to induce immune activation three times during early postnatal development (i.e., day 5, 8, and 11). On these days, C57BL/6J pups were administered either IL-1β (0.2 μg/kg) or saline vehicle followed, after 45 min, by either APAP (103.9 mg/kg) or vehicle. Mice were subsequently administered a battery of tests of social-emotional and repetitive behavior. A number of distinct long-term effects of IL-1β and APAP treatments were found, including sex-specific shifts in repetitive behavior and emotional hyperthermia following early-life IL-1β and increased social caution in males following early-life APAP. We also observed significant interaction between IL-1β and APAP: as adults, 'two-hit' IL-1β + APAP females displayed greater anxiety-related thigmotaxis across a number of tests, including an open field. 'Two hit' males, in turn, showed elevated levels of avoidance of an unfamiliar social partner during a social interaction test. Our results highlight that IL-1β-induced inflammation and APAP have both distinct effects and significant interactions during early life, with enduring sex-specific effects on phenotypes relevant to neurodevelopmental disorders.
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Affiliation(s)
- Christopher Harshaw
- Department of Psychology, University of New Orleans, New Orleans, LA, United States of America.
| | - Anna G Warner
- Department of Psychology, University of New Orleans, New Orleans, LA, United States of America
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Gore AC, Krishnan K, Reilly MP. Endocrine-disrupting chemicals: Effects on neuroendocrine systems and the neurobiology of social behavior. Horm Behav 2019; 111:7-22. [PMID: 30476496 PMCID: PMC6527472 DOI: 10.1016/j.yhbeh.2018.11.006] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/25/2018] [Accepted: 11/14/2018] [Indexed: 02/06/2023]
Abstract
A contribution to SBN/ICN special issue. Endocrine-disrupting chemicals (EDCs) are pervasive in the environment. They are found in plastics and plasticizers (bisphenol A (BPA) and phthalates), in industrial chemicals such as polychlorinated biphenyls (PCBs), and include some pesticides and fungicides such as vinclozolin. These chemicals act on hormone receptors and their downstream signaling pathways, and can interfere with hormone synthesis, metabolism, and actions. Because the developing brain is particularly sensitive to endogenous hormones, disruptions by EDCs can change neural circuits that form during periods of brain organization. Here, we review the evidence that EDCs affect developing hypothalamic neuroendocrine systems, and change behavioral outcomes in juvenile, adolescent, and adult life in exposed individuals, and even in their descendants. Our focus is on social, communicative and sociosexual behaviors, as how an individual behaves with a same- or opposite-sex conspecific determines that individual's ability to exist in a community, be selected as a mate, and reproduce successfully.
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Affiliation(s)
- Andrea C Gore
- Division of Pharmacology and Toxicology, The University of Texas at Austin, Austin, TX 78712, USA; Department of Psychology, The University of Texas at Austin, Austin, TX 78712, USA.
| | - Krittika Krishnan
- Department of Psychology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Michael P Reilly
- Division of Pharmacology and Toxicology, The University of Texas at Austin, Austin, TX 78712, USA
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3
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Bodi CM, Vassoler FM, Byrnes EM. Adolescent experience affects postnatal ultrasonic vocalizations and gene expression in future offspring. Dev Psychobiol 2016; 58:714-23. [PMID: 26999300 PMCID: PMC5320520 DOI: 10.1002/dev.21411] [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: 11/22/2015] [Accepted: 03/05/2016] [Indexed: 12/21/2022]
Abstract
The present study measured postnatal ultrasonic vocalization (USV) and gene expression to examine potential changes in communication and/or attachment in the offspring of mothers exposed to morphine during adolescence. Offspring of morphine-exposed (Mor-F1), saline-exposed (Sal-F1), or non-handled control (Con-F1) female Sprague-Dawley rats were tested for separation-induced distress calls and maternal potentiation of distress calls during early postnatal development. We also examined relative expression of dopamine D2 receptor and mu opioid receptor (oprm1) mRNA in the nucleus accumbens and hypothalamus in these offspring, as their activity has been implicated in the regulation of postnatal USV in response to maternal separation. The findings indicate that adolescent experiences of future mothers, including their 10 daily saline or morphine injections, can result in significant region-specific differences in gene expression. In addition, these experiences resulted in fewer numbers of separation-induced distress calls produced by offspring. In contrast, augmented maternal potentiation was only observed in Mor-F1 offspring. © 2016 Wiley Periodicals, Inc. Dev Psychobiol 58:714-723, 2016.
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Affiliation(s)
- Caroline M Bodi
- Department of Biomedical Sciences, Cummings School of Veterinary Medicine, Tufts University, 200 Westboro Road, North Grafton, 01536, MA
| | - Fair M Vassoler
- Department of Biomedical Sciences, Cummings School of Veterinary Medicine, Tufts University, 200 Westboro Road, North Grafton, 01536, MA
| | - Elizabeth M Byrnes
- Department of Biomedical Sciences, Cummings School of Veterinary Medicine, Tufts University, 200 Westboro Road, North Grafton, 01536, MA.
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Suvorov A, Vandenberg LN. To Cull or Not To Cull? Considerations for Studies of Endocrine-Disrupting Chemicals. Endocrinology 2016; 157:2586-94. [PMID: 27175970 PMCID: PMC4929555 DOI: 10.1210/en.2016-1145] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The power of animal models is derived from the ability to control experimental variables so that observed effects may be unequivocally attributed to the factor that was changed. One variable that is difficult to control in animal experiments is the number and composition of offspring in a litter. To account for this variability, artificial equalization of the number of offspring in a litter (culling) is often used. The rationale for culling, however, has always been controversial. The Developmental Origins of Health and Disease concept provides a new context to evaluate the pros and cons of culling in laboratory animal studies, especially in the context of endocrine-disrupting chemicals. Emerging evidence indicates that culling, especially of large litters, can drastically change the feeding status of a pup, which can result in compensatory growth with long-term consequences for the animal, including increased risk of cardio-metabolic diseases. Similarly, culling of litters to intentionally bias sex ratios can alter the animal's behavior and physiology, with effects observed on a wide range of outcomes. Thus, in an attempt to control for variability in developmental rates, culling introduces an uncontrolled or confounding variable, which itself may affect a broad spectrum of health-related consequences. Variabilities in culling protocols could be responsible for differences in responses to endocrine-disrupting chemicals reported across studies. Because litter sex composition and size are vectors that can influence both prenatal and postnatal growth, they are essential considerations for the interpretation of results from laboratory animal studies.
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Affiliation(s)
- Alexander Suvorov
- Department of Environmental Health Sciences, School of Public Health and Health Sciences, University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Laura N Vandenberg
- Department of Environmental Health Sciences, School of Public Health and Health Sciences, University of Massachusetts Amherst, Amherst, Massachusetts 01003
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Porter AJ, Pillidge K, Tsai YC, Dudley JA, Hunt SP, Peirson SN, Brown LA, Stanford SC. A lack of functional NK1 receptors explains most, but not all, abnormal behaviours of NK1R-/- mice(1). GENES BRAIN AND BEHAVIOR 2015; 14:189-99. [PMID: 25558794 PMCID: PMC4415486 DOI: 10.1111/gbb.12195] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 12/04/2014] [Accepted: 12/11/2014] [Indexed: 01/16/2023]
Abstract
Mice lacking functional neurokinin-1 receptors (NK1R-/-) display abnormal behaviours seen in Attention Deficit Hyperactivity Disorder (hyperactivity, impulsivity and inattentiveness). These abnormalities were evident when comparing the behaviour of separate (inbred: 'Hom') wildtype and NK1R-/- mouse strains. Here, we investigated whether the inbreeding protocol could influence their phenotype by comparing the behaviour of these mice with that of wildtype (NK1R+/+) and NK1R-/- progeny of heterozygous parents ('Het', derived from the same inbred strains). First, we recorded the spontaneous motor activity of the two colonies/genotypes, over 7 days. This continuous monitoring also enabled us to investigate whether the diurnal rhythm in motor activity differs in the two colonies/genotypes. NK1R-/- mice from both colonies were hyperactive compared with their wildtypes and their diurnal rhythm was also disrupted. Next, we evaluated the performance of the four groups of mice in the 5-Choice Serial Reaction-Time Task (5-CSRTT). During training, NK1R-/- mice from both colonies expressed more impulsive and perseverative behaviour than their wildtypes. During testing, only NK1R-/- mice from the Hom colony were more impulsive than their wildtypes, but NK1R-/- mice from both colonies were more perseverative. There were no colony differences in inattentiveness. Moreover, a genotype difference in this measure depended on time of day. We conclude that the hyperactivity, perseveration and, possibly, inattentiveness of NK1R-/- mice is a direct consequence of a lack of functional NK1R. However, the greater impulsivity of NK1R-/- mice depended on an interaction between a functional deficit of NK1R and other (possibly environmental and/or epigenetic) factors.
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Affiliation(s)
- A J Porter
- Department of Neuroscience, Physiology and Pharmacology
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Bensky MK, Gosling SD, Sinn DL. The World from a Dog’s Point of View. ADVANCES IN THE STUDY OF BEHAVIOR 2013. [DOI: 10.1016/b978-0-12-407186-5.00005-7] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Functions and physiological roles of two types of estrogen receptors, ERα and ERβ, identified by estrogen receptor knockout mouse. Lab Anim Res 2012; 28:71-6. [PMID: 22787479 PMCID: PMC3389841 DOI: 10.5625/lar.2012.28.2.71] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 05/21/2012] [Accepted: 05/25/2012] [Indexed: 01/23/2023] Open
Abstract
Estrogens, a class of steroid hormones, regulate the growth, development, and physiology of the human reproductive system. Estrogens also involve in the neuroendocrine, skeletal, adipogenesis, and cardiovascular systems. Estrogen signaling pathways are selectively stimulated or inhibited depending on a balance between the activities of estrogen receptor (ER) α or ERβ in target organs. ERs belong to the steroid hormone superfamily of nuclear receptors, which act as transcription factors after binding to estrogen. The gene expression regulation by ERs is to modulate biological activities, such as reproductive organ development, bone modeling, cardiovascular system functioning, metabolism, and behavior in both females and males. Understanding of the general physiological roles of ERs has been gained when estrogen levels were ablated by ovariectomy and then replenished by treatment with exogenous estrogen. This technique is not sufficient to fully determine the exact function of estrogen signaling in general processes in living tissues. However, a transgenic mouse model has been useful to study gene-specific functions. ERα and ERβ have different biological functions, and knockout and transgenic animal models have distinct phenotypes. Analysis of ERα and ERβ function using knockout mouse models has identified the roles of estrogen signaling in general physiologic processes. Although transgenic mouse models do not always produce consistent results, they are the useful for studying the functions of these genes under specific pathological conditions.
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Crews D. Epigenetic modifications of brain and behavior: theory and practice. Horm Behav 2011; 59:393-8. [PMID: 20633562 PMCID: PMC3401366 DOI: 10.1016/j.yhbeh.2010.07.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 06/25/2010] [Accepted: 07/06/2010] [Indexed: 01/11/2023]
Abstract
Evolutionary change is a product of selection. Selection operates on the phenotype, and its consequences are manifest in representation of the genotype in successive generations. Of particular interest to both evolutionary and behavioral biologists is the newly emerging field of epigenetics and behavior. Two broad categories of epigenetic modifications must be distinguished. Context-dependent epigenetic change can be observed if the environmental factors that bring about the epigenetic modification persists (e.g., the frequency and quality of maternal care modifying the brain and future behavior of the offspring each generation). Because the environment induces epiallelic change, removing the causative factor can reverse a context-dependent epigenetic state. Germline-dependent epigenetic change occurs when the epigenetic imprint is mediated through the germline. Such effects are independent of the causative agent and there is no evidence at present that a germline-dependent epigenetic state can be reversed. Finally, only germline-dependent epigenetic modifications can be truly transgenerational. Although an individual's life history is progressive and continuous, it might usefully be viewed as the cumulation of divisions: each period emerging from what has gone before and, at the same time, setting the stage for what follows. These life history stages are somewhat arbitrary, with many traits spanning conventional divisions, but each period tends to have its own characteristic ethologies and particular contribution to neural and behavioral phenotypes. To understand how these episodes 'fit' together, it is necessary to deconstruct early life events and study each period both in its' own right and how it interacts with the preceding and subsequent stages. Lastly, it seems intuitive that germline- and context-dependent epigenetic modifications interact, resulting in the individual variation observed in behaviors, but until now this hypothesis has never been tested experimentally.
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Affiliation(s)
- David Crews
- Section of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA.
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How Many Ways Can Mouse Behavioral Experiments Go Wrong? Confounding Variables in Mouse Models of Neurodegenerative Diseases and How to Control Them. ADVANCES IN THE STUDY OF BEHAVIOR 2010. [DOI: 10.1016/s0065-3454(10)41007-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Borg CL, Wolski KM, Gibbs GM, O'Bryan MK. Phenotyping male infertility in the mouse: how to get the most out of a 'non-performer'. Hum Reprod Update 2009; 16:205-24. [PMID: 19758979 PMCID: PMC2816191 DOI: 10.1093/humupd/dmp032] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Functional male gametes are produced through complex processes that take place within the testis, epididymis and female reproductive tract. A breakdown at any of these phases can result in male infertility. The production of mutant mouse models often yields an unexpected male infertility phenotype. It is with this in mind that the current review has been written. The review aims to act as a guide to the ‘non-reproductive biologist’ to facilitate a systematic analysis of sterile or subfertile mice and to assist in extracting the maximum amount of information from each model. METHODS This is a review of the original literature on defects in the processes that take a mouse spermatogonial stem cell through to a fully functional spermatozoon, which result in male infertility. Based on literature searches and personal experience, we have outlined a step-by-step strategy for the analysis of an infertile male mouse line. RESULTS A wide range of methods can be used to define the phenotype of an infertile male mouse. These methods range from histological methods such as electron microscopy and immunohistochemistry, to hormone analyses and methods to assess sperm maturation status and functional competence. CONCLUSION With the increased rate of genetically modified mouse production, the generation of mouse models with unexpected male infertility is increasing. This manuscript will help to ensure that the maximum amount of information is obtained from each mouse model and, by extension, will facilitate the knowledge of both normal fertility processes and the causes of human infertility.
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Affiliation(s)
- Claire L Borg
- Department of Anatomy and Developmental Biology, The School of Biomedical Sciences, Monash University, Clayton 3800, Australia
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Crews D, Rushworth D, Gonzalez-Lima F, Ogawa S. Litter environment affects behavior and brain metabolic activity of adult knockout mice. Front Behav Neurosci 2009; 3:12. [PMID: 19707539 PMCID: PMC2730751 DOI: 10.3389/neuro.08.012.2009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2009] [Accepted: 07/17/2009] [Indexed: 11/13/2022] Open
Abstract
In mammals, the formative environment for social and anxiety-related behaviors is the family unit; in the case of rodents, this is the litter and the mother-young bond. A deciding factor in this environment is the sex ratio of the litter and, in the case of mice lacking functional copies of gene(s), the ratio of the various genotypes in the litter. Both Sex and Genotype ratios of the litter affect the nature and quality of the individual's behavior later in adulthood, as well as metabolic activity in brain nuclei that underlie these behaviors. Mice were raised in litters reconstituted shortly after to birth to control for sex ratio and genotype ratio (wild type pups versus pups lacking a functional estrogen receptor alpha). In both males and females, the Sex and Genotype of siblings in the litter affected aggressive behaviors as well as patterns of metabolic activity in limbic nuclei in the social behavior network later in adulthood. Further, this pattern in males varied depending upon the Genotype of their brothers and sisters. Principal Components Analysis revealed two components comprised of several amygdalar and hypothalamic nuclei; the VMH showed strong correlations in both clusters, suggesting its pivotal nature in the organization of two neural networks.
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Affiliation(s)
- David Crews
- Section of Integrative Biology, University of Texas at Austin Austin, TX 78712, USA.
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Rose C, Röhl FW, Hanke J, Schwegler H, Yilmazer-Hanke DM. Maternal and genetic effects on the acoustic startle reflex and its sensitization in C3H/HeN, DBA/2JHd and NMRI mice following blastocyst transfer. Behav Genet 2008; 38:596-611. [PMID: 18719991 DOI: 10.1007/s10519-008-9222-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Accepted: 08/04/2008] [Indexed: 11/26/2022]
Abstract
In the present study, reciprocal embryo transfers were conducted to examine genetic and maternal effects on the baseline and fear-sensitized acoustic startle response (ASR) in the two inbred strains C3H/HeN and DBA/2JHd and the outbred strain NMRI. The largest differences in the ASR were found in untreated strains (effect size 0.6). The transfer procedure per se had a significant effect on the behavior of NMRI mice resulting in a reduction in the baseline, and an increase in the fear-sensitized ASR. In contrast, there were no significant effects of the transfer procedure in the two inbred strains. Autosomal genetic effects had a stronger impact on the amplitude of the ASR (effect sizes 0.5) than sex (effect sizes 0.06) as revealed by reciprocal embryo transfer. Nevertheless, the genetic effects on the fear-sensitized ASR were somewhat more variable and strain-dependent (effect sizes 0.1-0.2). Global maternal effects were detected after embryo transfer into NMRI mothers resulting in a larger reduction of the ASR in the offspring of DBA and NMRI donors than C3H donors (effect sizes 0.1-0.2). An additional fostering procedure was introduced to dissect uterine and postnatal maternal effects in NMRI offspring. Uterine factors changed the baseline ASR of the offspring in direction of the recipient mother strain. Surprisingly, postnatal maternal effects on the ASR were contrary to the behavior of the rearing mother. In conclusion, both genetic and prenatal/postnatal maternal factors persistently influenced the ASR of the offspring, whereas the fear-sensitized ASR was mainly influenced by genetic factors. Our study shows that uterine and postnatal maternal influences deserve more attention when determining the phenotype of genetically engineered mice at least in the first generation following embryo transfer.
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Affiliation(s)
- Claudia Rose
- Institut für Anatomie, Medizinische Fakultät, Otto-von-Guericke Universität, Magdeburg, Germany
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Crews D. Epigenetics and its implications for behavioral neuroendocrinology. Front Neuroendocrinol 2008; 29:344-57. [PMID: 18358518 PMCID: PMC2394853 DOI: 10.1016/j.yfrne.2008.01.003] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Revised: 12/28/2007] [Accepted: 01/30/2008] [Indexed: 12/16/2022]
Abstract
Individuals vary in their sociosexual behaviors and reactivity. How the organism interacts with the environment to produce this variation has been a focus in psychology since its inception as a scientific discipline. There is now no question that cumulative experiences throughout life history interact with genetic predispositions to shape the individual's behavior. Recent evidence suggests that events in past generations may also influence how an individual responds to events in their own life history. Epigenetics is the study of how the environment can affect the genome of the individual during its development as well as the development of its descendants, all without changing the DNA sequence. Several distinctions must be made if this research is to become a staple in behavioral neuroendocrinology. The first distinction concerns perspective, and the need to distinguish and appreciate, the differences between Molecular versus Molar epigenetics. Each has its own lineage of investigation, yet both appear to be unaware of one another. Second, it is important to distinguish the difference between Context-Dependent versus Germline-Dependent epigenetic modifications. In essence the difference is one of the mechanism of heritability or transmission within, as apposed to across, generations. This review illustrates these distinctions while describing several rodent models that have shown particular promise for unraveling the contribution of genetics and the environment on sociosexual behavior. The first focuses on genetically-modified mice and makes the point that the early litter environment alters subsequent brain activity and behavior. This work emphasizes the need to understand behavioral development when doing research with such animals. The second focuses on a new rat model in which the epigenome is permanently imprinted, an effect that crosses generations to impact the descendants without further exposure to the precipitating agent. This work raises the question of how events in generations past can have consequences at both the mechanistic, behavioral, and ultimately evolutionary levels.
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Affiliation(s)
- David Crews
- Section of Integrative Biology and Center of Behavioral Neuroendocrinology, University of Texas at Austin, Austin, TX 78712, USA.
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Crews D, Lou W, Fleming A, Ogawa S. From gene networks underlying sex determination and gonadal differentiation to the development of neural networks regulating sociosexual behavior. Brain Res 2006; 1126:109-21. [PMID: 16905124 PMCID: PMC2394678 DOI: 10.1016/j.brainres.2006.07.031] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Revised: 06/30/2006] [Accepted: 07/06/2006] [Indexed: 11/30/2022]
Abstract
Genes are not expressed in isolation any more than social behavior has meaning outside of society. Both are in dynamic flux with the immediate environment that the gene/individual finds itself, which in turn establishes the timing, pattern, and conditions of expression. This means that complex behaviors and their genetic underpinnings should be viewed as a cumulative process, or as the result of experiences up to that point in time and, at the same time, as setting the stage for what will follow. The evidence indicates that as experiences accumulate throughout life, early experiences shape how genes/individuals will respond to later experiences, whereas later experiences modify the effects of these earlier experiences. A method of graphically representing and analyzing change in gene and neural networks is presented. Results from several animal model systems will be described to illustrate these methods. First, we will consider the phenomenon of temperature-dependent sex determination in reptiles. We will illustrate how the experience of a particular temperature during a sensitive period of embryogenesis sculpts not only the patterns of expression of genes involved in sex determination and gonadal differentiation but also the morphological, physiological, neuroendocrine, and behavioral traits of the adult phenotype. The second model system concerns the effects of the sex ratio in the litter in rats, and the genotype ratio in the litter of transgenic mice, on the nature and frequency of maternal care and how this in turn influences the patterns of activation of identified neural circuits subserving the offspring's sociosexual behavior when it is an adult.
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Affiliation(s)
- David Crews
- Section of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA.
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Teuscher C, Noubade R, Spach K, McElvany B, Bunn JY, Fillmore PD, Zachary JF, Blankenhorn EP. Evidence that the Y chromosome influences autoimmune disease in male and female mice. Proc Natl Acad Sci U S A 2006; 103:8024-9. [PMID: 16702550 PMCID: PMC1472423 DOI: 10.1073/pnas.0600536103] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Experimental allergic encephalomyelitis (EAE), an autoimmune model of multiple sclerosis, is a complex disease influenced by genetic, intrinsic, and environmental factors. In this study, we questioned whether parent-of-origin effects influence EAE, using reciprocal F2 intercross progeny generated between EAE-susceptible SJL/J (S) and EAE-resistant B10.S/SgMcdJ (B) mice. EAE susceptibility and severity were found to be different in female BS x BS intercross mice as compared with females from the three other birth crosses (BS x SB, SB x SB, and SB x BS), and in fact, both traits in female mice resembled those of their male siblings. This masculinization is associated with transmission of the SJL/J Y chromosome and an increased male-to-female sex ratio. Related studies using progeny of C57BL/6J Y-chromosome substitution strains demonstrate that the Y chromosome again influences EAE in both male and female mice, and that the disease course in females resembles that of their male littermates. Importantly, these data provide experimental evidence supporting the existence of a Y-chromosome polymorphism capable of modifying autoimmune disease susceptibility in both males and females.
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Affiliation(s)
- Cory Teuscher
- Department of Medicine and Pathology and Medical Biostatistics, University of Vermont, Burlington, VT 05405, USA.
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Fuller T, Sarkar S, Crews D. The use of norms of reaction to analyze genotypic and environmental influences on behavior in mice and rats. Neurosci Biobehav Rev 2005; 29:445-56. [PMID: 15820549 DOI: 10.1016/j.neubiorev.2004.12.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2003] [Revised: 12/19/2004] [Accepted: 12/20/2004] [Indexed: 10/25/2022]
Abstract
Norms of reaction (NoRs) represent the phenotypic values of genotypes as functions of environmental parameters and permit the visualization of differences in phenotypic response of different genotypes. NoR graphs can be used to analyze interactions between genotypic and environmental factors during development to produce phenotypes in inbred strains of rats and mice. We describe the main features of NoRs, the history of their use in this context, and discuss several applications in behavioral neuroscience. In addition, we give a test for determining whether distinct strains have different NoRs.
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Affiliation(s)
- Trevon Fuller
- Section of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA.
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CREWS DAVID, GROOTHUIS TON. Tinbergen's fourth question, ontogeny: sexual and individual differentiation. ANIM BIOL 2005; 55:343-370. [PMID: 16501662 PMCID: PMC1382030 DOI: 10.1163/157075605774841003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Based on Tinbergen's view of the study of behavioural development we describe some recent advances and their importance in this field. We argue that the study of behavioural development should combine both proximate and ultimate approaches, and can help to understand how early subtle environmental factors shape consistent individual variation both between and within sexes. This is illustrated by reviewing the profound effects of incubation temperature on the development of brain and social behaviour in the leopard gecko, a species with temperature-dependent sex determination, and the effects of early exposure to steroid hormones on social behaviour in rodents and especially birds. Both are maternal effects: incubation temperature can be partly determined by the nest site where the mother deposited her eggs, while in both oviparous and viviparous vertebrates maternal hormones reach and influence the embryo. In the gecko, incubation temperature affects sexual and aggressive behaviour, growth, the hypothalamus-pituitary-gonadal axis, as well as the size, connectivity and metabolic capacity of certain brain areas. In this way not only is the gonad type determined, but so too is the morphological, physiological, neural, and behavioural phenotype established that explains much of within-sex variation. In rodents, maternal hormones affect similar aspects. In avian species, maternal hormones, deposited in the eggs, vary systematically between and within clutches and have both short- and long-lasting effects on competitive behaviour. Evidence suggests that mothers adaptively adjust hormone allocation to the environmental context. In addition, we discuss some effects of postnatal experience on behavioural development in geckos, mice and bird species. Our results also illustrate how the study of animal models other than rodents can help in understanding important developmental processes.
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Affiliation(s)
- DAVID CREWS
- Section of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
- *Corresponding author. E-mail:
| | - TON GROOTHUIS
- Behavioural Biology, University of Groningen, P.O. Box 14, 9750 AA, Haren, The Netherlands
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