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Keiser AA, Kramár EA, Dong T, Shanur S, Pirodan M, Ru N, Acharya MM, Baulch JE, Limoli CL, Wood MA. Systemic HDAC3 inhibition ameliorates impairments in synaptic plasticity caused by simulated galactic cosmic radiation exposure in male mice. Neurobiol Learn Mem 2021; 178:107367. [PMID: 33359392 PMCID: PMC8456980 DOI: 10.1016/j.nlm.2020.107367] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [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: 09/03/2020] [Revised: 12/05/2020] [Accepted: 12/15/2020] [Indexed: 12/18/2022]
Abstract
Deep space travel presents a number of measurable risks including exposure to a spectrum of radiations of varying qualities, termed galactic cosmic radiation (GCR) that are capable of penetrating the spacecraft, traversing through the body and impacting brain function. Using rodents, studies have reported that exposure to simulated GCR leads to cognitive impairments associated with changes in hippocampus function that can persist as long as one-year post exposure with no sign of recovery. Whether memory can be updated to incorporate new information in mice exposed to GCR is unknown. Further, mechanisms underlying long lasting impairments in cognitive function as a result of GCR exposure have yet to be defined. Here, we examined whether whole body exposure to simulated GCR using 6 ions and doses of 5 or 30 cGy interfered with the ability to update an existing memory or impact hippocampal synaptic plasticity, a cellular mechanism believed to underlie memory processes, by examining long term potentiation (LTP) in acute hippocampal slices from middle aged male mice 3.5-5 months after radiation exposure. Using a modified version of the hippocampus-dependent object location memory task developed by our lab termed "Objects in Updated Locations" (OUL) task we find that GCR exposure impaired hippocampus-dependent memory updating and hippocampal LTP 3.5-5 months after exposure. Further, we find that impairments in LTP are reversed through one-time systemic subcutaneous injection of the histone deacetylase 3 inhibitor RGFP 966 (10 mg/kg), suggesting that long lasting impairments in cognitive function may be mediated at least in part, through epigenetic mechanisms.
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Affiliation(s)
- A A Keiser
- Department of Neurobiology and Behavior, School of Biological Sciences University of California, Irvine 92697-2695, United States; Center for the Neurobiology of Learning and Memory (CNLM), University of California, Irvine 92697-2695, United States; Institute for Memory Impairments and Neurological Disorders (UCI MIND), University of California, Irvine 92697-2695, United States
| | - E A Kramár
- Department of Neurobiology and Behavior, School of Biological Sciences University of California, Irvine 92697-2695, United States; Center for the Neurobiology of Learning and Memory (CNLM), University of California, Irvine 92697-2695, United States; Institute for Memory Impairments and Neurological Disorders (UCI MIND), University of California, Irvine 92697-2695, United States
| | - T Dong
- Department of Neurobiology and Behavior, School of Biological Sciences University of California, Irvine 92697-2695, United States; Center for the Neurobiology of Learning and Memory (CNLM), University of California, Irvine 92697-2695, United States; Institute for Memory Impairments and Neurological Disorders (UCI MIND), University of California, Irvine 92697-2695, United States
| | - S Shanur
- Department of Neurobiology and Behavior, School of Biological Sciences University of California, Irvine 92697-2695, United States; Center for the Neurobiology of Learning and Memory (CNLM), University of California, Irvine 92697-2695, United States; Institute for Memory Impairments and Neurological Disorders (UCI MIND), University of California, Irvine 92697-2695, United States
| | - M Pirodan
- Department of Neurobiology and Behavior, School of Biological Sciences University of California, Irvine 92697-2695, United States; Center for the Neurobiology of Learning and Memory (CNLM), University of California, Irvine 92697-2695, United States; Institute for Memory Impairments and Neurological Disorders (UCI MIND), University of California, Irvine 92697-2695, United States
| | - N Ru
- Department of Radiation Oncology, University of California, Irvine 92697-2695, United States
| | - M M Acharya
- Department of Radiation Oncology, University of California, Irvine 92697-2695, United States
| | - J E Baulch
- Department of Radiation Oncology, University of California, Irvine 92697-2695, United States
| | - C L Limoli
- Department of Radiation Oncology, University of California, Irvine 92697-2695, United States.
| | - M A Wood
- Department of Neurobiology and Behavior, School of Biological Sciences University of California, Irvine 92697-2695, United States; Center for the Neurobiology of Learning and Memory (CNLM), University of California, Irvine 92697-2695, United States; Institute for Memory Impairments and Neurological Disorders (UCI MIND), University of California, Irvine 92697-2695, United States.
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Sato F, Omura S, Martinez NE, Kawai E, Pearson SF, Fernando V, Acharya MM, Chaitanya GV, Alexander JS, Ajuebor MN, Taniguchi M, Tsunoda I. Abstract 039: Natural Killer T Cells Play Protective Roles in Cardiovirus-Induced Myocarditis by Inducing Anti-Viral and Regulatory Cytokines. Circ Res 2013. [DOI: 10.1161/res.113.suppl_1.a039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Picornavirus infections have been known as a leading cause of viral myocarditis in humans. Theiler’s murine encephalomyelitis virus (TMEV) belongs to the genus Cardiovirus, the family Picornaviridae, and can cause myocarditis in susceptible mice. In viral myocarditis, viral replication in the heart and/or immune responses against virus as well as cardiac antigens (autoimmunity) can contribute to the pathogenesis. Natural killer T (NKT) cells can play a regulatory role in viral infections by producing anti-viral and anti-inflammatory cytokines; interferon (IFN)-γ can contribute to either viral clearance or tissue damage (immunopathology), while anti-inflammatory interleukin (IL)-10 has been suggested to regulate viral clearance or immunopathology. To determine the role of NKT cells in TMEV-induced myocarditis, we infected wild-type (WT) and NKT knockout (NKT KO, Jα18 KO) mice with TMEV. Myocarditis was monitored by echocardiography using the Vevo 770 system. During the acute (day 7) or chronic phase (day 60) of TMEV infection, cardiac pathology was evaluated by hematoxylin and eosin staining, and production of cytokines, including IFN-γ and IL-10, from spleen cells was measured by enzyme-linked immunosorbent assays. During the acute phase, the levels of left ventricular ejection fraction were significantly lower in NKT KO mice than in WT mice. Immunologically, NKT KO mice had lower levels of IFN-γ production than WT mice [IFN-γ (pg/ml): WT, 768 ± 533; NKT KO, 293 ± 190]. During the chronic phase, high intensity cardiac lesions were observed by echocardiography in NKT KO mice, but not in WT mice. Histologically, NKT KO mice developed moderate inflammation with basophilic degeneration and calcification in the heart, while WT mice had only mild inflammation in the heart. Immunologically, NKT KO mice had lower levels of IL-10 production compared with WT mice [IL-10 (pg/ml): WT, 1771 ± 381; NKT KO, 1199 ± 160]. These results suggest that NKT cells play a protective role in viral myocarditis by producing IFN-γ and IL-10, which contribute to viral clearance during the acute phase and the suppression of immunopathology during the chronic phase of disease, respectively.
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Affiliation(s)
- Fumitaka Sato
- Louisiana State Univ Health Sciences Cntr, Shreveport, LA
| | - Seiichi Omura
- Louisiana State Univ Health Sciences Cntr, Shreveport, LA
| | | | - Eiichiro Kawai
- Louisiana State Univ Health Sciences Cntr, Shreveport, LA
| | | | | | | | | | | | | | - Masaru Taniguchi
- RIKEN Rsch Cntr for Allergy and Immunology (RCAI), Yokohama, Japan
| | - Ikuo Tsunoda
- Louisiana State Univ Health Sciences Cntr, Shreveport, LA
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