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Konat GW. Neuroplasticity elicited by peripheral immune challenge with a viral mimetic. Brain Res 2024; 1846:149239. [PMID: 39284559 DOI: 10.1016/j.brainres.2024.149239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Revised: 08/31/2024] [Accepted: 09/12/2024] [Indexed: 09/20/2024]
Abstract
Peripheral viral infections are well known to profoundly alter brain function; however detailed mechanisms of this immune-to-brain communication have not been deciphered. This review focuses on studies of cerebral effects of peripheral viral challenge employing intraperitoneal injection of a viral mimetic, polyinosinic-polycytidylic acid (PIC). In this paradigm, PIC challenge induces the acute phase response (APR) characterized by a transient surge of circulating inflammatory factors, primarily IFNβ, IL-6 and CXCL10. The blood-borne factors, in turn, elicit the generation of CXCL10 by hippocampal neurons. Neurons also express the cognate receptor of CXCL10, i.e., CXCR3 implicating the existence of autocrine/paracrine signaling. The CXCL10/CXCR3 axis mediates the ensuing neuroplastic changes manifested as neuronal hyperexcitability, seizure hypersusceptibility, and sickness behavior. Electrophysiological studies revealed that the neuroplastic changes entail the potentiation of excitatory synapses likely at both pre- and postsynaptic loci. Excitatory synaptic transmission is further augmented by PIC challenge-induced elevation of extracellular glutamate that is mediated by astrocytes. In addition, the hyperexcitability of neuronal circuits might involve the repression of inhibitory signaling. Accordingly, CXCL10 released by neurons activates microglia whose processes invade perisomatic inhibitory synapses, resulting in a partial detachment of the presynaptic terminals, and thus, de-inhibition. This process might be facilitated by the cerebral complement system, which is also upregulated and activated by PIC challenge. Moreover, CXCL10 stimulates the expression of neuronal c-fos protein, another index of hyperexcitability. The reviewed studies form a foundation for full elucidation of the fascinating intersection between peripheral viral infections and neuroplasticity. Because the activation of such pathways may constitute a serious comorbidity factor for neuropathological conditions, this research would advance the development of preventive strategies.
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Affiliation(s)
- Gregory W Konat
- Department of Biochemistry and Molecular Medicine, Department of Neuroscience and Rockefeller Neuroscience Institute, West Virginia University School of Medicine, Morgantown, WV 26506, USA.
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2
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Weapons of stress reduction: (R,S)-ketamine and its metabolites as prophylactics for the prevention of stress-induced psychiatric disorders. Neuropharmacology 2023; 224:109345. [PMID: 36427554 DOI: 10.1016/j.neuropharm.2022.109345] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/13/2022] [Accepted: 11/15/2022] [Indexed: 11/25/2022]
Abstract
Exposure to stress is one of the greatest contributing factors to developing a psychiatric disorder, particularly in susceptible populations. Enhancing resilience to stress could be a powerful intervention to reduce the incidence of psychiatric disease and reveal insight into the pathophysiology of psychiatric disorders. (R,S)-ketamine and its metabolites have recently been shown to exert protective effects when administered before or after a variety of stressors and may be effective, tractable prophylactic compounds against psychiatric disease. Drug dosing, sex, age, and strain in preclinical rodent studies, significantly influence the prophylactic effects of (R,S)-ketamine and related compounds. Due to the broad neurobiological actions of (R,S)-ketamine, a variety of mechanisms have been proposed to contribute to the resilience-enhancing effects of this drug, including altering various transcription factors across the genome, enhancing inhibitory connections from the prefrontal cortex, and increasing synaptic plasticity in the hippocampus. Promisingly, select data have shown that (R,S)-ketamine may be an effective prophylactic against psychiatric disorders, such as postpartum depression (PPD). Overall, this review will highlight a brief history of the prophylactic effects of (R,S)-ketamine, the potential mechanisms underlying its protective actions, and possible future directions for translating prophylactic compounds to the clinic. This article is part of the Special Issue on 'Ketamine and its Metabolites'.
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Complement as a powerful "influencer" in the brain during development, adulthood and neurological disorders. Adv Immunol 2021; 152:157-222. [PMID: 34844709 DOI: 10.1016/bs.ai.2021.09.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The complement system was long considered as only a powerful effector arm of the immune system that, while critically protective, could lead to inflammation and cell death if overactivated, even in the central nervous system (CNS). However, in the past decade it has been recognized as playing critical roles in key physiological processes in the CNS, including neurogenesis and synaptic remodeling in the developing and adult brain. Inherent in these processes are the interactions with cells in the brain, and the cascade of interactions and functional consequences that ensue. As a result, investigations of therapeutic approaches for both suppressing excessive complement driven neurotoxicity and aberrant sculpting of neuronal circuits, require broad (and deep) knowledge of the functional activities of multiple components of this highly evolved and regulated system to avoid unintended negative consequences in the clinic. Advances in basic science are beginning to provide a roadmap for translation to therapeutics, with both small molecule and biologics. Here, we present examples of the critical roles of proper complement function in the development and sculpting of the nervous system, and in enabling rapid protection from infection and clearance of dying cells. Microglia are highlighted as important command centers that integrate signals from the complement system and other innate sensors that are programed to provide support and protection, but that direct detrimental responses to aberrant activation and/or regulation of the system. Finally, we present promising research areas that may lead to effective and precision strategies for complement targeted interventions to promote neurological health.
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Cieślik M, Gassowska-Dobrowolska M, Zawadzka A, Frontczak-Baniewicz M, Gewartowska M, Dominiak A, Czapski GA, Adamczyk A. The Synaptic Dysregulation in Adolescent Rats Exposed to Maternal Immune Activation. Front Mol Neurosci 2021; 13:555290. [PMID: 33519375 PMCID: PMC7840660 DOI: 10.3389/fnmol.2020.555290] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 11/27/2020] [Indexed: 12/18/2022] Open
Abstract
Maternal immune activation (MIA) is a risk factor for neurodevelopmental disorders in offspring, but the pathomechanism is largely unknown. The aim of our study was to analyse the molecular mechanisms contributing to synaptic alterations in hippocampi of adolescent rats exposed prenatally to MIA. MIA was evoked in pregnant female rats by i.p. administration of lipopolysaccharide at gestation day 9.5. Hippocampi of offspring (52-53-days-old rats) were analysed using transmission electron microscopy (TEM), qPCR and Western blotting. Moreover, mitochondrial membrane potential, activity of respiratory complexes, and changes in glutathione system were measured. It was found that MIA induced changes in hippocampi morphology, especially in the ultrastructure of synapses, including synaptic mitochondria, which were accompanied by impairment of mitochondrial electron transport chain and decreased mitochondrial membrane potential. These phenomena were in agreement with increased generation of reactive oxygen species, which was evidenced by a decreased reduced/oxidised glutathione ratio and an increased level of dichlorofluorescein (DCF) oxidation. Activation of cyclin-dependent kinase 5, and phosphorylation of glycogen synthase kinase 3β on Ser9 occurred, leading to its inhibition and, accordingly, to hypophosphorylation of microtubule associated protein tau (MAPT). Abnormal phosphorylation and dysfunction of MAPT, the manager of the neuronal cytoskeleton, harmonised with changes in synaptic proteins. In conclusion, this is the first study demonstrating widespread synaptic changes in hippocampi of adolescent offspring prenatally exposed to MIA.
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Affiliation(s)
- Magdalena Cieślik
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland
| | | | - Aleksandra Zawadzka
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland
| | | | - Magdalena Gewartowska
- Electron Microscopy Platform, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland
| | - Agnieszka Dominiak
- Department of Biochemistry and Pharmacogenomics, Faculty of Pharmacy, Medicine, Medical University of Warsaw, Warsaw, Poland
| | - Grzegorz A Czapski
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland
| | - Agata Adamczyk
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland
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Hennessy MB, Sensenbaugh JD, Molina AL, Schiml PA, Deak T. Presence of mother prompts dissociation of sickness behavior, fever, and hypothalamic gene expression in lipopolysaccharide-injected guinea pig pups. Dev Psychobiol 2020; 62:749-757. [PMID: 32115686 DOI: 10.1002/dev.21962] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 02/01/2020] [Accepted: 02/04/2020] [Indexed: 01/09/2023]
Abstract
During infection, sickness behaviors, such as a hunched stance with piloerection, can facilitate host resistance by supporting the generation and maintenance of fever. Fever, in turn, is mediated by hypothalamic neuroimmune signaling. Sickness behaviors, however, can also be influenced by social stimuli. In this study, guinea pig pups were injected with lipopolysaccharide to simulate a bacterial infection and then exposed to a novel, threatening environment while either with their mother or alone. We found that the presence of the mother suppressed sickness behavior, but enhanced fever, and had no measureable effect on gene expression of hypothalamic mediators of fever. This 3-way dissociation induced by the mother's presence is interpreted in terms of the differential adaptive consequences of behavioral and febrile responses for pups in this situation. The results contribute to a growing literature linking immunological and social processes.
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Affiliation(s)
| | | | - Andrea L Molina
- Department of Psychology, Wright State University, Dayton, OH, USA
| | | | - Terrence Deak
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY, USA
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Mastrodonato A, Cohensedgh O, LaGamma CT, McGowan JC, Hunsberger HC, Denny CA. Prophylactic (R,S)-ketamine selectively protects against inflammatory stressors. Behav Brain Res 2019; 378:112238. [PMID: 31563463 DOI: 10.1016/j.bbr.2019.112238] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/04/2019] [Accepted: 09/12/2019] [Indexed: 12/31/2022]
Abstract
Individuals with peripheral inflammation are a particularly vulnerable population for developing depression and are also more resistant towards traditional antidepressants. This signals the need for novel drugs that can effectively treat this patient population. Recently, we have demonstrated that (R,S)-ketamine is a prophylactic against a variety of stressors, but have yet to test if it is protective against inflammatory-induced vulnerability to a stressor. Here, male 129S6/SvEv mice were administered saline or (R,S)-ketamine (30 mg/kg) 6 days before an injection of vehicle (VEH) or lipopolysaccharide (LPS) (0.83 or 1.0 mg/kg, serotypes O111:B4 or O127:B8). Twenty-four hours after LPS administration, mice were administered a contextual fear conditioning (CFC) paradigm, followed by a context re-exposure and the forced swim test (FST). In a separate cohort, we tested if (R,S)-ketamine was effective as a prophylactic against polyinosinic-polycytidylic acid (PIC), a viral mimetic. (R,S)-ketamine was effective as a prophylactic for attenuating learned fear in the O111:B4 and O127:B8 strains of LPS. (R,S)-ketamine was also effective as a prophylactic for decreasing stress-induced depressive-like behavior in the O111:B4 and O127:B8 strains of LPS. Both of these effects were limited to administration of 1.0, but not 0.83 mg/kg of the O111:B4 and O127:B8 strains of LPS. (R,S)-ketamine was not effective against either stress phenotype following PIC administration. These data suggest that prophylactic (R,S)-ketamine may protect against selective inflammation-induced stress phenotypes following an inflammatory challenge. Future studies will be necessary to determine if (R,S)-ketamine can be useful in patient populations with peripheral inflammation.
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Affiliation(s)
- Alessia Mastrodonato
- Division of Systems Neuroscience, Research Foundation for Mental Hygiene, Inc. (RFMH)/New York State Psychiatric Institute (NYSPI), New York, NY, 10032, United States; Department of Psychiatry, Columbia University Irving Medical Center (CUIMC), New York, NY, 10032, United States
| | - Omid Cohensedgh
- Department of Psychiatry, Columbia University Irving Medical Center (CUIMC), New York, NY, 10032, United States
| | - Christina T LaGamma
- Division of Systems Neuroscience, Research Foundation for Mental Hygiene, Inc. (RFMH)/New York State Psychiatric Institute (NYSPI), New York, NY, 10032, United States
| | - Josephine C McGowan
- Doctoral Program in Neurobiology and Behavior, Columbia University, New York, NY, 10032, United States
| | - Holly C Hunsberger
- Division of Systems Neuroscience, Research Foundation for Mental Hygiene, Inc. (RFMH)/New York State Psychiatric Institute (NYSPI), New York, NY, 10032, United States; Department of Psychiatry, Columbia University Irving Medical Center (CUIMC), New York, NY, 10032, United States
| | - Christine A Denny
- Division of Systems Neuroscience, Research Foundation for Mental Hygiene, Inc. (RFMH)/New York State Psychiatric Institute (NYSPI), New York, NY, 10032, United States; Department of Psychiatry, Columbia University Irving Medical Center (CUIMC), New York, NY, 10032, United States.
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Zenz G, Jačan A, Reichmann F, Farzi A, Holzer P. Intermittent Fasting Exacerbates the Acute Immune and Behavioral Sickness Response to the Viral Mimic Poly(I:C) in Mice. Front Neurosci 2019; 13:359. [PMID: 31057355 PMCID: PMC6478699 DOI: 10.3389/fnins.2019.00359] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 03/28/2019] [Indexed: 12/18/2022] Open
Abstract
Intermitted fasting and other forms of calorie restriction are increasingly demonstrated to exert potential health benefits. Interestingly, restricted feeding is also able to mitigate sickness in response to bacterial factors stimulating Toll-like receptor 4 (TLR4). However, little is known about how fasting modifies the activity of virus-associated molecular patterns. We therefore analyzed the impact of an intermittent fasting (IF) regimen on the immune and behavioral response to the TLR3 agonist and viral mimic polyinosinic:polycytidylic acid [Poly(I:C)] in mice. The effects of intraperitoneally injected Poly(I:C) (12 mg/kg) on plasma and cerebral cytokine expression and behavior (locomotion, exploration, and ingestion) were examined in male C57BL/6N mice under control conditions and following a 9 days period of intermittent (alternate day) fasting (IF). Poly(I:C) increased the circulating levels of cytokines (TNF-α, MCP-1, IL-6, IL-10, IFN-α, IFN-γ), an effect amplified by IF. In addition, IF aggravated sickness behavior in response to Poly(I:C), while cerebral cytokine expression was enhanced by application of Poly(I:C) in the absence of a significant effect of IF. Furthermore, IF augmented the expression of neuropeptide Y (NPY) mRNA in the hypothalamus and increased the plasma levels of corticosterone, while Poly(I:C) had little effect on these readouts. Our data show that IF does not abate, but exaggerates the immune and sickness response to the viral mimic Poly(I:C). This adverse effect of IF occurs despite increased hypothalamic NPY expression and enhanced plasma corticosterone. We therefore propose that the effects of IF on the immune and behavioral responses to viral and bacterial factors are subject to different neuronal and neuroendocrine control mechanisms.
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Affiliation(s)
- Geraldine Zenz
- Research Unit of Translational Neurogastroenterology, Division of Pharmacology, Otto Loewi Research Center, Medical University of Graz, Graz, Austria
| | - Angela Jačan
- CBmed GmbH-Center for Biomarker Research in Medicine, Graz, Austria
| | - Florian Reichmann
- Research Unit of Translational Neurogastroenterology, Division of Pharmacology, Otto Loewi Research Center, Medical University of Graz, Graz, Austria
| | - Aitak Farzi
- Research Unit of Translational Neurogastroenterology, Division of Pharmacology, Otto Loewi Research Center, Medical University of Graz, Graz, Austria
| | - Peter Holzer
- Research Unit of Translational Neurogastroenterology, Division of Pharmacology, Otto Loewi Research Center, Medical University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria
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8
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Petrisko TJ, Konat GW. Peripheral viral challenge exacerbates experimental autoimmune encephalomyelitis. Metab Brain Dis 2019; 34:675-679. [PMID: 30637619 DOI: 10.1007/s11011-019-0383-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 01/03/2019] [Indexed: 10/27/2022]
Abstract
Peripheral viral infections are potent triggers of exacerbation in multiple sclerosis (MS). Here, we used a preclinical model of MS, the experimental autoimmune encephalomyelitis (EAE) to corroborate this comorbidity in an experimental setting. EAE was induced by immunization of mice with MOG peptide, and paralysis was scored using a 5-point scale. At the onset of the chronic phase of the disease (Days 42-58 after MOG injection) the animals were divided into low responders (LR) and high responders (HR) with the mean score of 1.5 and 2.5, respectively. The acute phase response (APR) was induced by intraperitoneal injections of a viral mimetic, polyinosinic-polycytidylic acid (PIC). Two daily injections were performed on Days 42 and 44 (PIC42,44 challenge) and on Days 54, 55 and 56 (PIC54,55,56 challenge). PIC42,44 challenge had no effect of EAE disease, whereas PIC54,55,56 challenge rapidly increased paralysis but only in HR group. This exacerbation ultimately led to animal death by Day 58. These results demonstrate that antiviral APR is a potent exacerbator of EAE, and that this activity directly correlates with the severity of the disease. This in turn, indicates that antiviral APR might play a pivot role in linking peripheral viral infections with MS exacerbations.
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Affiliation(s)
- Tiffany J Petrisko
- Departments of Biochemistry and Neuroscience, Rockefeller Neuroscience Institute, West Virginia University School of Medicine, 4052 HSCN, P.O. Box 9128, Morgantown, WV, 26506-9128, USA
| | - Gregory W Konat
- Departments of Biochemistry and Neuroscience, Rockefeller Neuroscience Institute, West Virginia University School of Medicine, 4052 HSCN, P.O. Box 9128, Morgantown, WV, 26506-9128, USA.
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9
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Mazarati AM, Lewis ML, Pittman QJ. Neurobehavioral comorbidities of epilepsy: Role of inflammation. Epilepsia 2017; 58 Suppl 3:48-56. [DOI: 10.1111/epi.13786] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2017] [Indexed: 12/28/2022]
Affiliation(s)
- Andrey M. Mazarati
- Neurology Division; Department of Pediatrics; David Geffen School of Medicine; University of California Los Angeles; Los Angeles California U.S.A
| | - Megan L. Lewis
- Department of Physiology & Pharmacology; Hotchkiss Brain Institute; University of Calgary; Calgary Alberta Canada
| | - Quentin J. Pittman
- Department of Physiology & Pharmacology; Hotchkiss Brain Institute; University of Calgary; Calgary Alberta Canada
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CX3CR1 + monocytes modulate learning and learning-dependent dendritic spine remodeling via TNF-α. Nat Med 2017; 23:714-722. [PMID: 28504723 PMCID: PMC5590232 DOI: 10.1038/nm.4340] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 04/11/2017] [Indexed: 02/07/2023]
Abstract
Impaired learning and cognitive function often occurs during systemic infection or inflammation. Although activation of the innate immune system has been linked to the behavioral and cognitive effects that are associated with infection, the underlying mechanisms remain poorly understood. Here we mimicked viral immune activation with poly(I:C), a synthetic analog of double-stranded RNA, and longitudinally imaged postsynaptic dendritic spines of layer V pyramidal neurons in the mouse primary motor cortex using two-photon microscopy. We found that peripheral immune activation caused dendritic spine loss, impairments in learning-dependent dendritic spine formation and deficits in multiple learning tasks in mice. These observed synaptic alterations in the cortex were mediated by peripheral-monocyte-derived cells and did not require microglial function in the central nervous system. Furthermore, activation of CX3CR1highLy6Clow monocytes impaired motor learning and learning-related dendritic spine plasticity through tumor necrosis factor (TNF)-α-dependent mechanisms. Taken together, our results highlight CX3CR1high monocytes and TNF-α as potential therapeutic targets for preventing infection-induced cognitive dysfunction.
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White JD, Eimerbrink MJ, Hayes HB, Hardy A, Van Enkevort EA, Peterman JL, Chumley MJ, Boehm GW. Hippocampal Aβ expression, but not phosphorylated tau, predicts cognitive deficits following repeated peripheral poly I:C administration. Behav Brain Res 2016; 313:219-225. [PMID: 27449203 DOI: 10.1016/j.bbr.2016.07.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 07/12/2016] [Accepted: 07/18/2016] [Indexed: 01/09/2023]
Abstract
Alzheimer's disease is marked by the accumulation of the amyloid-beta (Aβ) peptide, and increases in phosphorylation of the microtubule associated protein, tau. Changes in these proteins are considered responsible, in part, for the progressive neuronal degeneration and cognitive deficits seen in AD. We examined the effect of repeated consecutive peripheral poly I:C injections on cognitive deficits, central Aβ, and phosphorylated tau accumulation, following three treatment durations: 7, 14, and 21 days. Forty-eight hours after the final injection, animals were trained in a contextual fear-conditioning paradigm, and tested 24h later. Immediately after testing, the hippocampus was collected to quantify Aβ and phosphorylated tau accumulation. Results showed that, although poly I:C-induced Aβ was significantly elevated at all time points examined, poly I:C only disrupted cognition after 14 and 21 days of administration. Moreover, elevations in phosphorylated tau were not seen until the 14-day time point. Interestingly, phosphorylated tau expression then declined at the 21-day time point. Finally, we demonstrated that Aβ levels are a stronger predictor of cognitive dysfunction, explaining 37% of the variance, whereas phosphorylated tau levels only accounted for 0.2%. Taken together, these results support the hypothesis that inflammation-induced elevation in Aβ disrupts cognition, independently of phosphorylated tau, and suggest that long-term administration of poly I:C may provide a model to investigate the contribution of long-term inflammation toward the development of Alzheimer's-like pathology.
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Affiliation(s)
- J D White
- Department of Psychology, Texas Christian University, United States
| | - M J Eimerbrink
- Department of Psychology, Texas Christian University, United States
| | - H B Hayes
- Department of Biology, Texas Christian University, United States
| | - A Hardy
- Department of Biology, Texas Christian University, United States
| | - E A Van Enkevort
- Department of Psychology, Texas Christian University, United States
| | - J L Peterman
- Department of Psychology, Texas Christian University, United States
| | - M J Chumley
- Department of Biology, Texas Christian University, United States
| | - G W Boehm
- Department of Psychology, Texas Christian University, United States.
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Hunsberger HC, Wang D, Petrisko TJ, Alhowail A, Setti SE, Suppiramaniam V, Konat GW, Reed MN. Peripherally restricted viral challenge elevates extracellular glutamate and enhances synaptic transmission in the hippocampus. J Neurochem 2016; 138:307-16. [PMID: 27168075 PMCID: PMC4936939 DOI: 10.1111/jnc.13665] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 05/05/2016] [Accepted: 05/09/2016] [Indexed: 01/23/2023]
Abstract
Peripheral infections increase the propensity and severity of seizures in susceptible populations. We have previously shown that intraperitoneal injection of a viral mimic, polyinosinic-polycytidylic acid (PIC), elicits hypersusceptibility of mice to kainic acid (KA)-induced seizures. This study was undertaken to determine whether this seizure hypersusceptibility entails alterations in glutamate signaling. Female C57BL/6 mice were intraperitoneally injected with PIC, and after 24 h, glutamate homeostasis in the hippocampus was monitored using the enzyme-based microelectrode arrays. PIC challenge robustly increased the level of resting extracellular glutamate. While pre-synaptic potassium-evoked glutamate release was not affected, glutamate uptake was profoundly impaired and non-vesicular glutamate release was augmented, indicating functional alterations of astrocytes. Electrophysiological examination of hippocampal slices from PIC-challenged mice revealed a several fold increase in the basal synaptic transmission as compared to control slices. PIC challenge also increased the probability of pre-synaptic glutamate release as seen from a reduction of paired-pulse facilitation and synaptic plasticity as seen from an enhancement of long-term potentiation. Altogether, our results implicate a dysregulation of astrocytic glutamate metabolism and an alteration of excitatory synaptic transmission as the underlying mechanism for the development of hippocampal hyperexcitability, and consequently seizure hypersusceptibility following peripheral PIC challenge. Peripheral infections/inflammations enhance seizure susceptibility. Here, we explored the effect of peritoneal inflammation induced by a viral mimic on glutamate homeostasis and glutamatergic neurotransmission in the mouse hippocampus. We found that peritoneal inflammation elevated extracellular glutamate concentration and enhanced the probability of pre-synaptic glutamate release resulting in hyperexcitability of neuronal networks. These mechanisms are likely to underlie the enhanced seizure propensity.
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Affiliation(s)
- Holly C. Hunsberger
- Behavioral Neuroscience, Department of Psychology, West Virginia University, Morgantown, 26506 WV, USA
- Department of Drug Discovery and Development, School of Pharmacy, Auburn University, Auburn, 36849 AL, USA
| | - Desheng Wang
- Blanchette Rockefeller Neurosciences Institute, Morgantown, 26506 WV, USA
| | - Tiffany J. Petrisko
- Department of Neurobiology and Anatomy, School of Medicine, West Virginia University, Morgantown, 26506 WV, USA
| | - Ahmad Alhowail
- Department of Drug Discovery and Development, School of Pharmacy, Auburn University, Auburn, 36849 AL, USA
| | - Sharay E. Setti
- Department of Drug Discovery and Development, School of Pharmacy, Auburn University, Auburn, 36849 AL, USA
| | - Vishnu Suppiramaniam
- Department of Drug Discovery and Development, School of Pharmacy, Auburn University, Auburn, 36849 AL, USA
| | - Gregory W. Konat
- Department of Neurobiology and Anatomy, School of Medicine, West Virginia University, Morgantown, 26506 WV, USA
| | - Miranda N. Reed
- Department of Drug Discovery and Development, School of Pharmacy, Auburn University, Auburn, 36849 AL, USA
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