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O'Connor AM, Hagenauer MH, Thew Forrester LC, Maras PM, Arakawa K, Hebda-Bauer EK, Khalil H, Richardson ER, Rob FI, Sannah Y, Watson SJ, Akil H. Adolescent environmental enrichment induces social resilience and alters neural gene expression in a selectively bred rodent model with anxious phenotype. Neurobiol Stress 2024; 31:100651. [PMID: 38933284 PMCID: PMC11201356 DOI: 10.1016/j.ynstr.2024.100651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 04/10/2024] [Accepted: 05/24/2024] [Indexed: 06/28/2024] Open
Abstract
Stress is a major influence on mental health status; the ways that individuals respond to or copes with stressors determine whether they are negatively affected in the future. Stress responses are established by an interplay between genetics, environment, and life experiences. Psychosocial stress is particularly impactful during adolescence, a critical period for the development of mood disorders. In this study we compared two established, selectively-bred Sprague Dawley rat lines, the "internalizing" bred Low Responder (bLR) line versus the "externalizing" bred High Responder (bHR) line, to investigate how genetic temperament and adolescent environment impact future responses to social interactions and psychosocial stress, and how these determinants of stress response interact. Male bLR and bHR rats were exposed to social and environmental enrichment in adolescence prior to experiencing social defeat and were then assessed for social interaction and anxiety-like behavior. Adolescent enrichment caused rats to display more social interaction, as well as nominally less social avoidance, less submission during defeat, and resilience to the effects of social stress on corticosterone, in a manner that seemed more notable in bLRs. For bHRs, enrichment also caused greater aggression during a neutral social encounter and nominally during defeat, and decreased anxiety-like behavior. To explore the neurobiology underlying the development of social resilience in the anxious phenotype bLRs, RNA-seq was conducted on the hippocampus and nucleus accumbens, two brain regions that mediate stress regulation and social behavior. Gene sets previously associated with stress, social behavior, aggression and exploratory activity were enriched with differential expression in both regions, with a particularly large effect on gene sets that regulate social behaviors. Our findings provide further evidence that adolescent enrichment can serve as an inoculating experience against future stressors. The ability to induce social resilience in a usually anxious line of animals by manipulating their environment has translational implications, as it underscores the feasibility of intervention strategies targeted at genetically vulnerable adolescent populations.
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Affiliation(s)
| | - Megan Hastings Hagenauer
- Michigan Neuroscience Institute, 205 Zina Pitcher Place, University of Michigan, Ann Arbor, MI, USA, 48109
| | - Liam Cannon Thew Forrester
- Michigan Neuroscience Institute, 205 Zina Pitcher Place, University of Michigan, Ann Arbor, MI, USA, 48109
| | - Pamela M. Maras
- Michigan Neuroscience Institute, 205 Zina Pitcher Place, University of Michigan, Ann Arbor, MI, USA, 48109
| | - Keiko Arakawa
- Michigan Neuroscience Institute, 205 Zina Pitcher Place, University of Michigan, Ann Arbor, MI, USA, 48109
| | - Elaine K. Hebda-Bauer
- Michigan Neuroscience Institute, 205 Zina Pitcher Place, University of Michigan, Ann Arbor, MI, USA, 48109
| | - Huzefa Khalil
- Michigan Neuroscience Institute, 205 Zina Pitcher Place, University of Michigan, Ann Arbor, MI, USA, 48109
| | - Evelyn R. Richardson
- Michigan Neuroscience Institute, 205 Zina Pitcher Place, University of Michigan, Ann Arbor, MI, USA, 48109
| | - Farizah I. Rob
- Michigan Neuroscience Institute, 205 Zina Pitcher Place, University of Michigan, Ann Arbor, MI, USA, 48109
| | - Yusra Sannah
- Michigan Neuroscience Institute, 205 Zina Pitcher Place, University of Michigan, Ann Arbor, MI, USA, 48109
| | - Stanley J. Watson
- Michigan Neuroscience Institute, 205 Zina Pitcher Place, University of Michigan, Ann Arbor, MI, USA, 48109
| | - Huda Akil
- Michigan Neuroscience Institute, 205 Zina Pitcher Place, University of Michigan, Ann Arbor, MI, USA, 48109
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2
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O'Connor AM, Hagenauer MH, Forrester LCT, Maras PM, Arakawa K, Hebda-Bauer EK, Khalil H, Richardson ER, Rob FI, Sannah Y, Watson SJ, Akil H. Adolescent environmental enrichment induces social resilience and alters neural gene expression in a selectively bred rodent model with anxious phenotype. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.03.560702. [PMID: 38645129 PMCID: PMC11030238 DOI: 10.1101/2023.10.03.560702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Stress is a major influence on mental health status; the ways that individuals respond to or copes with stressors determine whether they are negatively affected in the future. Stress responses are established by an interplay between genetics, environment, and life experiences. Psychosocial stress is particularly impactful during adolescence, a critical period for the development of mood disorders. In this study we compared two established, selectively-bred Sprague Dawley rat lines, the "internalizing" bred Low Responder (bLR) line versus the "externalizing" bred High Responder (bHR) line, to investigate how genetic temperament and adolescent environment impact future responses to social interactions and psychosocial stress, and how these determinants of stress response interact. Male bLR and bHR rats were exposed to social and environmental enrichment in adolescence prior to experiencing social defeat and were then assessed for social interaction and anxiety-like behavior. Adolescent enrichment caused rats to display more social interaction, as well as nominally less social avoidance, less submission during defeat, and resilience to the effects of social stress on corticosterone, in a manner that seemed more notable in bLRs. For bHRs, enrichment also caused greater aggression during a neutral social encounter and nominally during defeat, and decreased anxiety-like behavior. To explore the neurobiology underlying the development of social resilience in the anxious phenotype bLRs, RNA-seq was conducted on the hippocampus and nucleus accumbens, two brain regions that mediate stress regulation and social behavior. Gene sets previously associated with stress, social behavior, aggression and exploratory activity were enriched with differential expression in both regions, with a particularly large effect on gene sets that regulate social behaviors. Our findings provide further evidence that adolescent enrichment can serve as an inoculating experience against future stressors. The ability to induce social resilience in a usually anxious line of animals by manipulating their environment has translational implications, as it underscores the feasibility of intervention strategies targeted at genetically vulnerable adolescent populations.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Huda Akil
- Univ. of Michigan, Ann Arbor, MI, USA
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Chitre AS, Hebda-Bauer EK, Blandino P, Bimschleger H, Nguyen KM, Maras P, Li F, Ozel AB, Pan Y, Polesskaya O, Cheng R, Flagel SB, Watson SJ, Li J, Akil H, Palmer AA. Genome-wide association study in a rat model of temperament identifies multiple loci for exploratory locomotion and anxiety-like traits. Front Genet 2023; 13:1003074. [PMID: 36712851 PMCID: PMC9873817 DOI: 10.3389/fgene.2022.1003074] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/20/2022] [Indexed: 01/12/2023] Open
Abstract
Common genetic factors likely contribute to multiple psychiatric diseases including mood and substance use disorders. Certain stable, heritable traits reflecting temperament, termed externalizing or internalizing, play a large role in modulating vulnerability to these disorders. To model these heritable tendencies, we selectively bred rats for high and low exploration in a novel environment [bred High Responders (bHR) vs. Low Responders (bLR)]. To identify genes underlying the response to selection, we phenotyped and genotyped 538 rats from an F2 cross between bHR and bLR. Several behavioral traits show high heritability, including the selection trait: exploratory locomotion (EL) in a novel environment. There were significant phenotypic and genetic correlations between tests that capture facets of EL and anxiety. There were also correlations with Pavlovian conditioned approach (PavCA) behavior despite the lower heritability of that trait. Ten significant and conditionally independent loci for six behavioral traits were identified. Five of the six traits reflect different facets of EL that were captured by three behavioral tests. Distance traveled measures from the open field and the elevated plus maze map onto different loci, thus may represent different aspects of novelty-induced locomotor activity. The sixth behavioral trait, number of fecal boli, is the only anxiety-related trait mapping to a significant locus on chromosome 18 within which the Pik3c3 gene is located. There were no significant loci for PavCA. We identified a missense variant in the Plekhf1 gene on the chromosome 1:95 Mb QTL and Fancf and Gas2 as potential candidate genes that may drive the chromosome 1:107 Mb QTL for EL traits. The identification of a locomotor activity-related QTL on chromosome 7 encompassing the Pkhd1l1 and Trhr genes is consistent with our previous finding of these genes being differentially expressed in the hippocampus of bHR vs. bLR rats. The strong heritability coupled with identification of several loci associated with exploratory locomotion and emotionality provide compelling support for this selectively bred rat model in discovering relatively large effect causal variants tied to elements of internalizing and externalizing behaviors inherent to psychiatric and substance use disorders.
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Affiliation(s)
- Apurva S. Chitre
- Department of Psychiatry, University of California San Diego, La Jolla, CA, United States
| | - Elaine K. Hebda-Bauer
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, United States
| | - Peter Blandino
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, United States
| | - Hannah Bimschleger
- Department of Psychiatry, University of California San Diego, La Jolla, CA, United States
| | - Khai-Minh Nguyen
- Department of Psychiatry, University of California San Diego, La Jolla, CA, United States
| | - Pamela Maras
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, United States
| | - Fei Li
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, United States
| | - A. Bilge Ozel
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, United States
| | - Yanchao Pan
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, United States
| | - Oksana Polesskaya
- Department of Psychiatry, University of California San Diego, La Jolla, CA, United States
| | - Riyan Cheng
- Department of Psychiatry, University of California San Diego, La Jolla, CA, United States
| | - Shelly B. Flagel
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, United States
| | - Stanley J. Watson
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, United States
| | - Jun Li
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, United States
| | - Huda Akil
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, United States
| | - Abraham A. Palmer
- Department of Psychiatry, University of California San Diego, La Jolla, CA, United States,Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, United States,*Correspondence: Abraham A. Palmer,
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Ornitz DM, Itoh N. New developments in the biology of fibroblast growth factors. WIREs Mech Dis 2022; 14:e1549. [PMID: 35142107 PMCID: PMC10115509 DOI: 10.1002/wsbm.1549] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 01/28/2023]
Abstract
The fibroblast growth factor (FGF) family is composed of 18 secreted signaling proteins consisting of canonical FGFs and endocrine FGFs that activate four receptor tyrosine kinases (FGFRs 1-4) and four intracellular proteins (intracellular FGFs or iFGFs) that primarily function to regulate the activity of voltage-gated sodium channels and other molecules. The canonical FGFs, endocrine FGFs, and iFGFs have been reviewed extensively by us and others. In this review, we briefly summarize past reviews and then focus on new developments in the FGF field since our last review in 2015. Some of the highlights in the past 6 years include the use of optogenetic tools, viral vectors, and inducible transgenes to experimentally modulate FGF signaling, the clinical use of small molecule FGFR inhibitors, an expanded understanding of endocrine FGF signaling, functions for FGF signaling in stem cell pluripotency and differentiation, roles for FGF signaling in tissue homeostasis and regeneration, a continuing elaboration of mechanisms of FGF signaling in development, and an expanding appreciation of roles for FGF signaling in neuropsychiatric diseases. This article is categorized under: Cardiovascular Diseases > Molecular and Cellular Physiology Neurological Diseases > Molecular and Cellular Physiology Congenital Diseases > Stem Cells and Development Cancer > Stem Cells and Development.
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Affiliation(s)
- David M Ornitz
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nobuyuki Itoh
- Kyoto University Graduate School of Pharmaceutical Sciences, Sakyo, Kyoto, Japan
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Maras PM, Hebda-Bauer EK, Hagenauer MH, Hilde KL, Blandino P, Watson SJ, Akil H. Differences in microglia morphological profiles reflect divergent emotional temperaments: insights from a selective breeding model. Transl Psychiatry 2022; 12:105. [PMID: 35292624 PMCID: PMC8924221 DOI: 10.1038/s41398-022-01821-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 12/20/2021] [Accepted: 01/14/2022] [Indexed: 12/12/2022] Open
Abstract
Microglia play critical roles in healthy brain development and function, as well as the neuropathology underlying a range of brain diseases. Despite evidence for a role of microglia in affective regulation and mood disorders, little is known regarding how variation in microglia status relates to individual differences in emotionality. Using a selective breeding model, we have generated rat lines with unique temperamental phenotypes that reflect broad emotional traits: bred low responder rats (bLRs) are novelty-averse and model a passive coping style, whereas bred high responder rats (bHRs) are highly exploratory and model an active coping style. To identify a functional role of microglia in these phenotypes, we administered minocycline, an antibiotic with potent microglia inhibiting properties and observed shifts in forced swim, sucrose preference, and social interaction behaviors in bLRs. Using detailed anatomical analyses, we compared hippocampal microglia profiles of bHRs and bLRs and found that although the lines had similar numbers of microglia, selective breeding was associated with a shift in the morphological features of these cells. Specifically, microglia from bLRs were characterized by a hyper-ramified morphology, with longer processes and more complicated branching patterns than microglia from bHRs. This morphology is thought to reflect an early stage of microglia activation and suggests that bLR microglia are in a reactive state even when animals are not overtly challenged. Taken together, our results provide novel evidence linking variation in inborn temperament with differences in the baseline status of microglia and implicate a role for microglia in shaping enduring emotional characteristics.
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Affiliation(s)
- Pamela M Maras
- The Michigan Neuroscience Institute, University of Michigan School of Medicine, Ann Arbor, MI, 48109, USA.
| | - Elaine K Hebda-Bauer
- The Michigan Neuroscience Institute, University of Michigan School of Medicine, Ann Arbor, MI, 48109, USA
| | - Megan H Hagenauer
- The Michigan Neuroscience Institute, University of Michigan School of Medicine, Ann Arbor, MI, 48109, USA
| | - Kathryn L Hilde
- The Michigan Neuroscience Institute, University of Michigan School of Medicine, Ann Arbor, MI, 48109, USA
| | - Peter Blandino
- The Michigan Neuroscience Institute, University of Michigan School of Medicine, Ann Arbor, MI, 48109, USA
| | - Stanley J Watson
- The Michigan Neuroscience Institute, University of Michigan School of Medicine, Ann Arbor, MI, 48109, USA
| | - Huda Akil
- The Michigan Neuroscience Institute, University of Michigan School of Medicine, Ann Arbor, MI, 48109, USA
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Palmer S, Oppler SH, Graham ML. Behavioral Management as a Coping Strategy for Managing Stressors in Primates: The Influence of Temperament and Species. BIOLOGY 2022; 11:biology11030423. [PMID: 35336797 PMCID: PMC8945664 DOI: 10.3390/biology11030423] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/05/2022] [Accepted: 03/09/2022] [Indexed: 05/28/2023]
Abstract
Primates involved in biomedical research experience stressors related to captivity, close contact with caregivers, and may be exposed to various medical procedures while modeling clinical disease or interventions under study. Behavioral management is used to promote behavioral flexibility in less complex captive environments and train coping skills to reduce stress. How animals perceive their environment and interactions is the basis of subjective experience and has a major impact on welfare. Certain traits, such as temperament and species, can affect behavioral plasticity and learning. This study investigated the relationship between these traits and acquisition of coping skills in 83 macaques trained for cooperation with potentially aversive medical procedures using a mixed-reinforcement training paradigm. All primates successfully completed training with no significant differences between inhibited and exploratory animals, suggesting that while temperament profoundly influences behavior, training serves as an important equalizer. Species-specific differences in learning and motivation manifested in statistically significant faster skill acquisition in rhesus compared with cynomolgus macaques, but this difference was not clinically relevant. Despite unique traits, primates were equally successful in learning complex tasks and displayed effective coping. When animals engage in coping behaviors, their distress decreases, improving welfare and reducing inter- and intra- subject variability to enhance scientific validity.
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Affiliation(s)
- Sierra Palmer
- Department of Surgery, University of Minnesota, Minneapolis, MN 55108, USA; (S.P.); (S.H.O.)
- Department of Veterinary Population Medicine, University of Minnesota, St. Paul, MN 55108, USA
| | - Scott Hunter Oppler
- Department of Surgery, University of Minnesota, Minneapolis, MN 55108, USA; (S.P.); (S.H.O.)
- Department of Veterinary Population Medicine, University of Minnesota, St. Paul, MN 55108, USA
| | - Melanie L. Graham
- Department of Surgery, University of Minnesota, Minneapolis, MN 55108, USA; (S.P.); (S.H.O.)
- Department of Veterinary Population Medicine, University of Minnesota, St. Paul, MN 55108, USA
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7
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Birt IA, Hagenauer MH, Clinton SM, Aydin C, Blandino P, Stead JD, Hilde KL, Meng F, Thompson RC, Khalil H, Stefanov A, Maras P, Zhou Z, Hebda-Bauer EK, Goldman D, Watson SJ, Akil H. Genetic Liability for Internalizing Versus Externalizing Behavior Manifests in the Developing and Adult Hippocampus: Insight From a Meta-analysis of Transcriptional Profiling Studies in a Selectively Bred Rat Model. Biol Psychiatry 2021; 89:339-355. [PMID: 32762937 PMCID: PMC7704921 DOI: 10.1016/j.biopsych.2020.05.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/29/2020] [Accepted: 05/19/2020] [Indexed: 01/05/2023]
Abstract
BACKGROUND For more than 16 years, we have selectively bred rats for either high or low levels of exploratory activity within a novel environment. These bred high-responder (bHR) and bred low-responder (bLR) rats model temperamental extremes, exhibiting large differences in internalizing and externalizing behaviors relevant to mood and substance use disorders. METHODS We characterized persistent differences in gene expression related to bHR/bLR phenotype across development and adulthood in the hippocampus, a region critical for emotional regulation, by meta-analyzing 8 transcriptional profiling datasets (microarray and RNA sequencing) spanning 43 generations of selective breeding (postnatal day 7: n = 22; postnatal day 14: n = 49; postnatal day 21: n = 21; adult: n = 46; all male). We cross-referenced expression differences with exome sequencing within our colony to pinpoint candidates likely to mediate the effect of selective breeding on behavioral phenotype. The results were compared with hippocampal profiling from other bred rat models. RESULTS Genetic and transcriptional profiling results converged to implicate multiple candidate genes, including two previously associated with metabolism and mood: Trhr and Ucp2. Results also highlighted bHR/bLR functional differences in the hippocampus, including a network essential for neurodevelopmental programming, proliferation, and differentiation, centering on Bmp4 and Mki67. Finally, we observed differential expression related to microglial activation, which is important for synaptic pruning, including 2 genes within implicated chromosomal regions: C1qa and Mfge8. CONCLUSIONS These candidate genes and functional pathways may direct bHR/bLR rats along divergent developmental trajectories and promote a widely different reactivity to the environment.
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Affiliation(s)
- Isabelle A. Birt
- Molecular and Behavioral Neuroscience Institute, University of
Michigan, Ann Arbor, Michigan
| | - Megan H. Hagenauer
- Molecular and Behavioral Neuroscience Institute, University of
Michigan, Ann Arbor, Michigan
| | | | - Cigdem Aydin
- Molecular and Behavioral Neuroscience Institute, University of
Michigan, Ann Arbor, Michigan
| | - Peter Blandino
- Molecular and Behavioral Neuroscience Institute, University of
Michigan, Ann Arbor, Michigan
| | - John D.H. Stead
- Department of Neuroscience, Carleton University, Ottawa, Ontario,
Canada
| | - Kathryn L. Hilde
- Molecular and Behavioral Neuroscience Institute, University of
Michigan, Ann Arbor, Michigan
| | - Fan Meng
- Molecular and Behavioral Neuroscience Institute, University of
Michigan, Ann Arbor, Michigan
| | - Robert C. Thompson
- Molecular and Behavioral Neuroscience Institute, University of
Michigan, Ann Arbor, Michigan
| | - Huzefa Khalil
- Molecular and Behavioral Neuroscience Institute, University of
Michigan, Ann Arbor, Michigan
| | - Alex Stefanov
- Molecular and Behavioral Neuroscience Institute, University of
Michigan, Ann Arbor, Michigan
| | - Pamela Maras
- Molecular and Behavioral Neuroscience Institute, University of
Michigan, Ann Arbor, Michigan
| | - Zhifeng Zhou
- National Institute on Alcohol Abuse and Alcoholism, National
Institutes of Health, Bethesda, Maryland
| | - Elaine K. Hebda-Bauer
- Molecular and Behavioral Neuroscience Institute, University of
Michigan, Ann Arbor, Michigan
| | - David Goldman
- National Institute on Alcohol Abuse and Alcoholism, National
Institutes of Health, Bethesda, Maryland
| | - Stanley J. Watson
- Molecular and Behavioral Neuroscience Institute, University of
Michigan, Ann Arbor, Michigan
| | - Huda Akil
- Molecular and Behavioral Neuroscience Institute, University of
Michigan, Ann Arbor, Michigan
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8
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Shupe EA, Glover ME, Unroe KA, Kerman IA, Clinton SM. Inborn differences in emotional behavior coincide with alterations in hypothalamic paraventricular motor projections. Eur J Neurosci 2020; 53:814-826. [PMID: 33249622 DOI: 10.1111/ejn.15065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/12/2020] [Accepted: 11/23/2020] [Indexed: 11/30/2022]
Abstract
Integrated behavioral responses to emotionally salient stimuli require the concomitant activation of descending neural circuits that integrate physiological, affective, and motor responses to stress. Our previous work interrogated descending circuits in the brainstem and spinal cord that project to motor and sympathetic targets. The hypothalamic paraventricular nucleus (PVN), a key node of this circuitry, integrates multiple motor and sympathetic responses activated by stress. The present study sought to determine whether descending projections from the PVN to targets in muscle and adrenal gland are differentially organized in rats with inborn differences in emotionality and stress responsivity. We utilized retrograde transsynaptic tract-tracing with unique pseudorabies virus (PRV) recombinants that were injected into sympathectomized gastrocnemius muscle and adrenal gland in two rat models featuring inborn differences in emotional behavior. Our tract-tracing results revealed a significant decrease in the number of PVN neurons with poly-synaptic projections to the gastrocnemius in male Wistar Kyoto [WKY] rats (versus Sprague Dawley rats) and selectively bred Low Novelty Responder [bLR] rats (versus selectively bred High Novelty Responder [bHR] rats). These neuroanatomical differences mirrored behavioral observations showing that both WKY and bLR rats display marked inhibition of emotional motor responses in a variety of settings relative to their respective controls. Our findings suggest that, in male rodents, PVN poly-synaptic projections to skeletal muscle may regulate emotional motor and coping responses to stress. More broadly, perturbations in PVN motor circuitry may play a role in mediating psychomotor disturbances observed in depression or anxiety-related disorders.
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Affiliation(s)
- Elizabeth A Shupe
- School of Neuroscience, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA
| | - Matthew E Glover
- School of Neuroscience, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA
| | - Keaton A Unroe
- School of Neuroscience, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA.,Translational Biology, Medicine and Health Graduate Program, Virginia Tech, Blacksburg, VA, USA
| | - Ilan A Kerman
- School of Neuroscience, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA.,Behavioral Service Line, Veterans Affairs Pittsburgh Health System, Pittsburgh, PA, USA
| | - Sarah M Clinton
- School of Neuroscience, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA
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9
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Isgor C, Aydin C, Oztan O, Libreros S, Iragavarapu-Charyulu V. Inter-individual differences in immune profiles of outbred rats screened for an emotional reactivity phenotype. J Neuroimmunol 2020; 347:577349. [PMID: 32750564 DOI: 10.1016/j.jneuroim.2020.577349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/24/2020] [Accepted: 07/26/2020] [Indexed: 11/28/2022]
Abstract
Inter-individual differences in emotional reactivity predict susceptibility versus resilience to mood pathology. Using experimentally-naïve outbred rats that vary in locomotor reactivity to the mild stress of an inescapable novel environment [i.e., top and bottom 1/3rd of the population identified as high responders (HR) and low responders (LR) respectively], we determined baseline variations in immune functions. Innate and adaptive immune responses vary basally in LRHR rats, namely a shift towards TH1 in LRs and TH2 in HRs was observed. These inter-individual variations in immune profiles in LRHRs could have significant implications in mood alterations and immune reactivity to microbes and cancer.
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Affiliation(s)
- Ceylan Isgor
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, United States of America
| | - Cigdem Aydin
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, United States of America
| | - Ozge Oztan
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, United States of America
| | - Stephania Libreros
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, United States of America
| | - Vijaya Iragavarapu-Charyulu
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, United States of America.
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