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Woodburn SC, Asrat HS, Flurer JK, Schwierling HC, Bollinger JL, Vollmer LL, Wohleb ES. Depletion of microglial BDNF increases susceptibility to the behavioral and synaptic effects of chronic unpredictable stress. Brain Behav Immun 2023; 109:127-138. [PMID: 36681359 PMCID: PMC10023455 DOI: 10.1016/j.bbi.2023.01.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 12/22/2022] [Accepted: 01/16/2023] [Indexed: 01/20/2023] Open
Abstract
In the medial prefrontal cortex (PFC), chronic stress reduces synaptic expression of glutamate receptors, leading to decreased excitatory signaling from layer V pyramidal neurons and working memory deficits. One key element driving these changes is a reduction in brain-derived neurotrophic factor (BDNF) signaling. BDNF is a potent mediator of synaptic growth and deficient BDNF signaling has been linked to stress susceptibility. Prior studies indicated that neurons are the primary source of BDNF, but more recent work suggests that microglia are also an important source of BDNF. Adding to this, our work showed that 14 days of chronic unpredictable stress (CUS) reduced Bdnf transcript in PFC microglia, evincing its relevance in the effects of stress. To explore this further, we utilized transgenic mice with microglia-specific depletion of BDNF (Cx3cr1Cre/+:Bdnffl/fl) and genotype controls (Cx3cr1Cre/+:Bdnf+/+). In the following experiments, mice were exposed to a shortened CUS paradigm (7 days) to determine if microglial Bdnf depletion promotes stress susceptibility. Analyses of PFC microglia revealed that Cx3cr1Cre/+:Bdnffl/fl mice had shifts in phenotypic markers and gene expression. In a separate cohort, synaptoneurosomes were collected from the PFC and western blotting was performed for synaptic markers. These experiments showed that Cx3cr1Cre/+:Bdnffl/fl mice had baseline deficits in GluN2B, and that 7 days of CUS additionally reduced GluN2A levels in Cx3cr1Cre/+:Bdnffl/fl mice, but not genotype controls. Behavioral and cognitive testing showed that this coincided with exacerbated stress effects on temporal object recognition in Cx3cr1Cre/+:Bdnffl/fl mice. These results indicate that microglial BDNF promotes glutamate receptor expression in the PFC. As such, mice with deficient microglial BDNF had increased susceptibility to the behavioral and cognitive consequences of stress.
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Affiliation(s)
- Samuel C Woodburn
- Department of Pharmacology & Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA; Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Helina S Asrat
- Department of Pharmacology & Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - James K Flurer
- Department of Pharmacology & Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Hana C Schwierling
- Department of Pharmacology & Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Justin L Bollinger
- Department of Pharmacology & Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Lauren L Vollmer
- Department of Pharmacology & Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Eric S Wohleb
- Department of Pharmacology & Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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Manivasagam S, Williams JL, Vollmer LL, Bollman B, Bartleson JM, Ai S, Wu GF, Klein RS. Targeting IFN-λ Signaling Promotes Recovery from Central Nervous System Autoimmunity. J Immunol 2022; 208:1341-1351. [PMID: 35181638 PMCID: PMC9012116 DOI: 10.4049/jimmunol.2101041] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
Type III IFNs (IFNLs) are newly discovered cytokines, acting at epithelial and other barriers, that exert immunomodulatory functions in addition to their primary roles in antiviral defense. In this study, we define a role for IFNLs in maintaining autoreactive T cell effector function and limiting recovery in a murine model of multiple sclerosis (MS), experimental autoimmune encephalomyelitis. Genetic or Ab-based neutralization of the IFNL receptor (IFNLR) resulted in lack of disease maintenance during experimental autoimmune encephalomyelitis, with loss of CNS Th1 effector responses and limited axonal injury. Phenotypic effects of IFNLR signaling were traced to increased APC function, with associated increase in T cell production of IFN-γ and GM-CSF. Consistent with this, IFNL levels within lesions of CNS tissues derived from patients with MS were elevated compared with MS normal-appearing white matter. Furthermore, expression of IFNLR was selectively elevated in MS active lesions compared with inactive lesions or normal-appearing white matter. These findings suggest IFNL signaling as a potential therapeutic target to prevent chronic autoimmune neuroinflammation.
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Affiliation(s)
- Sindhu Manivasagam
- Department of Medicine, Washington University in St. Louis, St. Louis, MO
| | | | - Lauren L Vollmer
- Department of Medicine, Washington University in St. Louis, St. Louis, MO
| | - Bryan Bollman
- Department of Neurology, Washington University in St. Louis, St. Louis, MO; and
| | - Juliet M Bartleson
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO
| | - Shenjian Ai
- Department of Medicine, Washington University in St. Louis, St. Louis, MO
| | - Gregory F Wu
- Department of Neurology, Washington University in St. Louis, St. Louis, MO; and
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO
| | - Robyn S Klein
- Department of Medicine, Washington University in St. Louis, St. Louis, MO;
- Department of Neurology, Washington University in St. Louis, St. Louis, MO; and
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO
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Williams JL, Manivasagam S, Smith BC, Sim J, Vollmer LL, Daniels BP, Russell JH, Klein RS. Astrocyte-T cell crosstalk regulates region-specific neuroinflammation. Glia 2020; 68:1361-1374. [PMID: 31961459 PMCID: PMC7317491 DOI: 10.1002/glia.23783] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 12/17/2019] [Accepted: 01/05/2020] [Indexed: 12/24/2022]
Abstract
During multiple sclerosis (MS), an inflammatory and neurodegenerative disease of the central nervous system (CNS), symptoms, and outcomes are determined by the location of inflammatory lesions. While we and others have shown that T cell cytokines differentially regulate leukocyte entry into perivascular spaces and regional parenchymal localization in murine models of MS, the molecular mechanisms of this latter process are poorly understood. Here, we demonstrate that astrocytes exhibit region-specific responses to T cell cytokines that promote hindbrain versus spinal cord neuroinflammation. Analysis of cytokine receptor expression in human astrocytes showed region-specific responsiveness to Th1 and Th17 inflammatory cytokines. Consistent with this, human and murine astrocytes treated with these cytokines exhibit differential expression of the T cell localizing molecules VCAM-1 and CXCR7 that is both cytokine and CNS region-specific. Using in vivo models of spinal cord versus brain stem trafficking of myelin-specific T cells and astrocyte-specific deletion strategies, we confirmed that Th1 and Th17 cytokines differentially regulate astrocyte expression of VCAM-1 and CXCR7 in these locations. Finally, stereotaxic injection of individual cytokines into the hindbrain or spinal cord revealed region- and cytokine-specific modulation of localizing cue expression by astrocytes. These findings identify a role for inflammatory cytokines in mediating local astrocyte-dependent mechanisms of immune cell trafficking within the CNS during neuroinflammation.
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Affiliation(s)
- Jessica L. Williams
- Department of Neurosciences, Lerner Research InstituteCleveland Clinic FoundationClevelandOhio
- Department of MedicineWashington University School of MedicineSt. LouisMissouri
| | - Sindhu Manivasagam
- Department of MedicineWashington University School of MedicineSt. LouisMissouri
| | - Brandon C. Smith
- Department of Neurosciences, Lerner Research InstituteCleveland Clinic FoundationClevelandOhio
| | - Julia Sim
- Department of Developmental BiologyWashington University School of MedicineSt. LouisMissouri
| | - Lauren L. Vollmer
- Department of MedicineWashington University School of MedicineSt. LouisMissouri
| | - Brian P. Daniels
- Department of MedicineWashington University School of MedicineSt. LouisMissouri
| | - John H. Russell
- Department of Developmental BiologyWashington University School of MedicineSt. LouisMissouri
| | - Robyn S. Klein
- Department of MedicineWashington University School of MedicineSt. LouisMissouri
- Department of Pathology and ImmunologyWashington University School of MedicineSt. LouisMissouri
- Department of Anatomy and NeurobiologyWashington University School of MedicineSt. LouisMissouri
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Garber C, Soung A, Vollmer LL, Kanmogne M, Last A, Brown J, Klein RS. T cells promote microglia-mediated synaptic elimination and cognitive dysfunction during recovery from neuropathogenic flaviviruses. Nat Neurosci 2019; 22:1276-1288. [PMID: 31235930 PMCID: PMC6822175 DOI: 10.1038/s41593-019-0427-y] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 05/16/2019] [Indexed: 11/09/2022]
Abstract
T cells clear virus from the CNS and dynamically regulate brain functions, including spatial learning, through cytokine signaling. Here we determined whether hippocampal T cells that persist after recovery from infection with West Nile virus (WNV) or Zika virus (ZIKV) impact hippocampal-dependent learning and memory. Using newly established models of viral encephalitis recovery in adult animals, we show that in mice that have recovered from WNV or ZIKV infection, T cell-derived interferon-γ (IFN-γ) signaling in microglia underlies spatial-learning defects via virus-target-specific mechanisms. Following recovery from WNV infection, mice showed presynaptic termini elimination with lack of repair, while for ZIKV, mice showed extensive neuronal apoptosis with loss of postsynaptic termini. Accordingly, animals deficient in CD8+ T cells or IFN-γ signaling in microglia demonstrated protection against synapse elimination following WNV infection and decreased neuronal apoptosis with synapse recovery following ZIKV infection. Thus, T cell signaling to microglia drives post-infectious cognitive sequelae that are associated with emerging neurotropic flaviviruses.
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Affiliation(s)
- Charise Garber
- Department of Internal Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - Allison Soung
- Department of Internal Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - Lauren L Vollmer
- Department of Internal Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - Marlene Kanmogne
- Department of Internal Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - Aisling Last
- Department of Internal Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - Jasmine Brown
- Department of Internal Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - Robyn S Klein
- Department of Internal Medicine, Washington University School of Medicine, St Louis, MO, USA.
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA.
- Department of Neuroscience, Washington University School of Medicine, St Louis, MO, USA.
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Luo H, Winkelmann ER, Zhu S, Ru W, Mays E, Silvas JA, Vollmer LL, Gao J, Peng BH, Bopp NE, Cromer C, Shan C, Xie G, Li G, Tesh R, Popov VL, Shi PY, Sun SC, Wu P, Klein RS, Tang SJ, Zhang W, Aguilar PV, Wang T. Peli1 facilitates virus replication and promotes neuroinflammation during West Nile virus infection. J Clin Invest 2018; 128:4980-4991. [PMID: 30247157 PMCID: PMC6205407 DOI: 10.1172/jci99902] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 08/07/2018] [Indexed: 12/16/2022] Open
Abstract
The E3 ubiquitin ligase Pellino 1 (Peli1) is a microglia-specific mediator of autoimmune encephalomyelitis. Its role in neurotropic flavivirus infection is largely unknown. Here, we report that mice deficient in Peli1 (Peli1-/-) were more resistant to lethal West Nile virus (WNV) infection and exhibited reduced viral loads in tissues and attenuated brain inflammation. Peli1 mediates chemokine and proinflammatory cytokine production in microglia and promotes T cell and macrophage infiltration into the CNS. Unexpectedly, Peli1 was required for WNV entry and replication in mouse macrophages and mouse and human neurons and microglia. It was also highly expressed on WNV-infected neurons and adjacent inflammatory cells from postmortem patients who died of acute WNV encephalitis. WNV passaged in Peli1-/- macrophages or neurons induced a lower viral load and impaired activation in WT microglia and thereby reduced lethality in mice. Smaducin-6, which blocks interactions between Peli1 and IRAK1, RIP1, and IKKε, did not inhibit WNV-triggered microglia activation. Collectively, our findings suggest a nonimmune regulatory role for Peli1 in promoting microglia activation during WNV infection and identify a potentially novel host factor for flavivirus cell entry and replication.
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Affiliation(s)
- Huanle Luo
- Department of Microbiology and Immunology
| | | | - Shuang Zhu
- Department of Ophthalmology and Visual Sciences
| | - Wenjuan Ru
- Department of Neuroscience, Cell Biology and Anatomy, and
| | | | - Jesus A. Silvas
- Department of Pathology, University of Texas Medical Branch (UTMB), Galveston, Texas, USA
| | - Lauren L. Vollmer
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Junling Gao
- Department of Neuroscience, Cell Biology and Anatomy, and
| | - Bi-Hung Peng
- Department of Neuroscience, Cell Biology and Anatomy, and
| | - Nathen E. Bopp
- Department of Pathology, University of Texas Medical Branch (UTMB), Galveston, Texas, USA
| | - Courtney Cromer
- Department of Pathology, University of Texas Medical Branch (UTMB), Galveston, Texas, USA
| | - Chao Shan
- Department of Biochemistry and Molecular Biology, and
| | - Guorui Xie
- Department of Microbiology and Immunology
| | - Guangyu Li
- Department of Microbiology and Immunology
| | - Robert Tesh
- Department of Pathology, University of Texas Medical Branch (UTMB), Galveston, Texas, USA.,Institute for Human Infections and Immunity, UTMB, Galveston, Texas, USA
| | - Vsevolod L. Popov
- Department of Pathology, University of Texas Medical Branch (UTMB), Galveston, Texas, USA.,Institute for Human Infections and Immunity, UTMB, Galveston, Texas, USA
| | - Pei-Yong Shi
- Department of Biochemistry and Molecular Biology, and,Institute for Human Infections and Immunity, UTMB, Galveston, Texas, USA
| | - Shao-Cong Sun
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Ping Wu
- Department of Neuroscience, Cell Biology and Anatomy, and,Institute for Human Infections and Immunity, UTMB, Galveston, Texas, USA
| | - Robyn S. Klein
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Shao-Jun Tang
- Department of Neuroscience, Cell Biology and Anatomy, and,Institute for Human Infections and Immunity, UTMB, Galveston, Texas, USA
| | - Wenbo Zhang
- Department of Ophthalmology and Visual Sciences,,Department of Neuroscience, Cell Biology and Anatomy, and,Institute for Human Infections and Immunity, UTMB, Galveston, Texas, USA
| | - Patricia V. Aguilar
- Department of Pathology, University of Texas Medical Branch (UTMB), Galveston, Texas, USA.,Institute for Human Infections and Immunity, UTMB, Galveston, Texas, USA
| | - Tian Wang
- Department of Microbiology and Immunology,,Department of Pathology, University of Texas Medical Branch (UTMB), Galveston, Texas, USA.,Institute for Human Infections and Immunity, UTMB, Galveston, Texas, USA
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Strawn JR, Vollmer LL, McMurray KM, Mills JA, Mossman SA, Varney ST, Schroeder HK, Sah R. Acid-sensing T cell death associated gene-8 receptor expression in panic disorder. Brain Behav Immun 2018; 67:36-41. [PMID: 28736033 PMCID: PMC5696091 DOI: 10.1016/j.bbi.2017.07.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 07/18/2017] [Accepted: 07/19/2017] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND While disruption of acid-base homeostasis has been pathoetiologically implicated in panic disorder (PD), the mechanism by which pH imbalance is translated to panic pathophysiology is poorly understood. Recently, in a translational rodent model of PD, we reported a role of microglial acid sensing G-protein coupled receptor, T cell death associated gene-8 (TDAG8) in panic-associated behavior and physiology. However, the clinical validity of the TDAG8 receptor has not been investigated. OBJECTIVE To assess TDAG8 in PD, we evaluated TDAG8 receptor expression in adolescents and young adults with PD and healthy comparison subjects. METHODS Relative expression of TDAG8 mRNA was determined in peripheral blood mononuclear cells from patients with PD, and compared to expression in healthy subjects. Linear models were utilized to evaluate the relationship between TDAG8 expression and panic disorder symptom severity scale (PDSS) score as well as other potential explanatory variables (e.g., CRP, body mass index, sex, age). Models were refined based on the estimated parameter significance, evidence of omitted variable bias and Bayesian/Akaike information criteria. RESULTS Relative to healthy comparison subjects (n=17), expression of TDAG8 mRNA was significantly increased in patients with PD (n=15) (1.60±0.65 vs. 1.01±0.50, p=0.008). TDAG8 mRNA expression predicted PD symptom severity in a fixed effect model incorporating age and sex (p=0.003). CONCLUSIONS Collectively, our results suggest greater TDAG8 expression in patients with PD compared to healthy subjects, and directly link TDAG8 expression and the severity of the PD symptoms. Further investigation of the TDAG8 receptor in panic pathophysiology is warranted.
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Affiliation(s)
- Jeffrey R. Strawn
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, College of Medicine, Cincinnati, OH 45237,Cincinnati Children's Hospital Medical Center, Department of Psychiatry, Cincinnati, Ohio, 45219
| | - Lauren L. Vollmer
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, College of Medicine, Cincinnati, OH 45237
| | - Katherine M.J. McMurray
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, College of Medicine, Cincinnati, OH 45237
| | - Jeffrey A. Mills
- Carl Lindner College of Business, University of Cincinnati, Cincinnati, OH
| | - Sarah A. Mossman
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, College of Medicine, Cincinnati, OH 45237
| | - Sara T. Varney
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, College of Medicine, Cincinnati, OH 45237
| | - Heidi K. Schroeder
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, College of Medicine, Cincinnati, OH 45237
| | - Renu Sah
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, College of Medicine, Cincinnati, OH 45237,Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH 45219,VA Medical Center, Cincinnati, OH 45220
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Vollmer LL, Schmeltzer S, Schurdak J, Ahlbrand R, Rush J, Dolgas CM, Baccei ML, Sah R. Neuropeptide Y Impairs Retrieval of Extinguished Fear and Modulates Excitability of Neurons in the Infralimbic Prefrontal Cortex. J Neurosci 2016; 36:1306-15. [PMID: 26818517 PMCID: PMC6604823 DOI: 10.1523/jneurosci.4955-13.2016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 11/23/2015] [Accepted: 12/16/2015] [Indexed: 11/21/2022] Open
Abstract
Neuropeptide Y (NPY), a 36 aa peptide, regulates stress and emotional behaviors. Preclinical and clinical studies support an association of NPY with trauma-evoked syndromes such as posttraumatic stress disorder (PTSD), although the exact contribution of NPY is not clear. In the current study, we examined functional attributes of NPY in the infralimbic (IL) cortex, an area that regulates fear memories and is reported to be hypoactive in PTSD. Carriers of NPY gene polymorphism rs16147 have been reported to have elevated prefrontal NPY expression. Infusion of NPY into the IL cortex in rats significantly impaired fear extinction memory without affecting conditioned fear expression or acquisition of extinction. Neuroendocrine stress response, depression-like behavior, and working memory performance were not affected by NPY infusion into the IL. The NPY Y1 receptor antagonist BIBO3304 completely abolished NPY effects on fear extinction retrieval. Y1 receptor expression was localized on CaMKII-positive pyramidal projection neurons and GAD67-positive interneurons in the IL. Patch-clamp recordings revealed increased inhibitory synaptic transmission onto IL projection neurons in the presence of NPY. Thus, NPY dampens excitability of IL projection neurons and impairs retrieval of extinction memory by inhibiting consolidation of extinction. Of relevance to PTSD, elevation of prefrontal NPY attributable to the genetic polymorphism rs16147 may contribute to IL hypoactivity, resulting in impaired extinction memory and susceptibility to the disorder. SIGNIFICANCE STATEMENT Neuropeptide Y (NPY), a stress modulatory transmitter, is associated with posttraumatic stress disorder (PTSD). Contribution of NPY to PTSD symptomology is unclear. PTSD patients have reduced activity in the infralimbic (IL) subdivision of the medial prefrontal cortex (mPFC), associated with compromised extinction memory. No information exists on fear modulation by NPY in the IL cortex, although NPY and NPY receptors are abundant in these areas. This study shows that IL NPY inhibits consolidation of extinction, resulting in impaired retrieval of extinction memory and modulates excitability of IL projection neurons. In addition to providing a novel perspective on extinction memory modulation by NPY, our findings suggest that elevated mPFC NPY in gene polymorphism rs16147 carriers or after chronic stress could increase susceptibility to PTSD.
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Affiliation(s)
- Lauren L Vollmer
- Departments of Psychiatry and Behavioral Neuroscience and Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio 45221, and
| | - Sarah Schmeltzer
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio 45221, and
| | | | | | - Jennifer Rush
- Departments of Psychiatry and Behavioral Neuroscience and
| | | | - Mark L Baccei
- Anesthesiology and Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio 45221, and
| | - Renu Sah
- Departments of Psychiatry and Behavioral Neuroscience and Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio 45221, and Veterans Administration Medical Center, Cincinnati, Ohio 45220
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Vollmer LL, Strawn JR, Sah R. Acid-base dysregulation and chemosensory mechanisms in panic disorder: a translational update. Transl Psychiatry 2015; 5:e572. [PMID: 26080089 PMCID: PMC4471296 DOI: 10.1038/tp.2015.67] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Revised: 02/19/2015] [Accepted: 04/06/2015] [Indexed: 12/13/2022] Open
Abstract
Panic disorder (PD), a complex anxiety disorder characterized by recurrent panic attacks, represents a poorly understood psychiatric condition which is associated with significant morbidity and an increased risk of suicide attempts and completed suicide. Recently however, neuroimaging and panic provocation challenge studies have provided insights into the pathoetiology of panic phenomena and have begun to elucidate potential neural mechanisms that may underlie panic attacks. In this regard, accumulating evidence suggests that acidosis may be a contributing factor in induction of panic. Challenge studies in patients with PD reveal that panic attacks may be reliably provoked by agents that lead to acid-base dysbalance such as CO2 inhalation and sodium lactate infusion. Chemosensory mechanisms that translate pH into panic-relevant fear, autonomic, and respiratory responses are therefore of high relevance to the understanding of panic pathophysiology. Herein, we provide a current update on clinical and preclinical studies supporting how acid-base imbalance and diverse chemosensory mechanisms may be associated with PD and discuss future implications of these findings.
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Affiliation(s)
- L L Vollmer
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, College of Medicine, Cincinnati, OH, USA
| | - J R Strawn
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, College of Medicine, Cincinnati, OH, USA,Cincinnati Children's Hospital Medical Center, Department of Psychiatry, Cincinnati, OH, USA
| | - R Sah
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, College of Medicine, Cincinnati, OH, USA,Veterens' Affairs Medical Center, Cincinnati, OH, USA,Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, 2170 East Galbraith Road, Cincinnati, OH 45237, USA. E-mail:
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Abstract
Chronicity of trauma exposure plays an important role in the pathophysiology of posttraumatic stress disorder (PTSD). Thus, exposure to multiple traumas on a chronic scale leads to worse outcomes than acute events. The rationale for the current study was to investigate the effects of a single adverse event versus the same event on a background of chronic stress. We hypothesized that a history of chronic stress would lead to worse behavioral outcomes than a single event alone. Male rats (n = 14/group) were exposed to either a single traumatic event in the form of electric foot shocks (acute shock, AS), or to footshocks on a background of chronic stress (chronic variable stress-shock, CVS-S). PTSD-relevant behaviors (fear memory and acoustic startle responses) were measured following 7 d recovery. In line with our hypothesis, CVS-S elicited significant increases in fear acquisition and conditioning versus the AS group. Unexpectedly, CVS-S elicited reduced startle reactivity to an acoustic stimulus in comparison with the AS group. Significant increase in FosB/ΔFosB-like immunostaining was observed in the dentate gyrus, basolateral amygdala and medial prefrontal cortex of CVS-S rats. Assessments of neuropeptide Y (NPY), a stress-regulatory transmitter associated with chronic PTSD, revealed selective reduction in the hippocampus of CVS-S rats. Collectively, our data show that cumulative stress potentiates delayed fear memory and impacts defensive responding. Altered neuronal activation in forebrain limbic regions and reduced NPY may contribute to these phenomena. Our preclinical studies support clinical findings reporting worse PTSD outcomes stemming from cumulative traumatization in contrast to acute trauma.
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Affiliation(s)
- Sarah N Schmeltzer
- Neuroscience Graduate Program, University of Cincinnati , Cincinnati, OH , USA
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