若手道場

若手道場2

2021/9/30　11:00～12:00　ZOOM 若手道場 WD2-0 【演題取消】		2021/9/30　11:00～12:00　ZOOM 若手道場 WD2-1 SARS-CoV-2 ORF9bはMARK2の活性阻害によりミクログリアからのサイトカインの放出を促進する SARS-CoV-2 ORF9b promotes cytokine release from microglial cells via inhibition of Microtubule affinity-regulating kinase 2 ^○福地葵¹, Taro Saito^1,2, Kanae Ando^1,2 1.東京都立大学　理学部　生命科学科, 2.Department of Biological Sciences, Graduate school of Science, Tokyo Metropolitan University ^○Aoi Fukuchi¹, Taro Saito^1,2, Kanae Ando^1,2 1.Department of Biological Sciences, Faculty of Science, Tokyo Metropolitan University, 2.Department of Biological Sciences, Graduate school of Science, Tokyo Metropolitan University The novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes Coronavirus disease 2019 (COVID-19). In addition to the main clinical manifestations with respiratory or intestinal symptoms, neurological symptoms have been frequently reported. The virus induces brain inflammation via the direct entry to the central nervous system or in response to the systemic cytokine storm. SARS-CoV-2 protein Orf9b plays a role in immune responses in the host cells. Upon exposure to RNA viruses, a host antiviral state is induced by an intracellular antiviral response initiated by activation of the receptors and a signaling complex on the mitochondrial outer membrane, including TOM70. Orf9b associates with TOM70 and suppresses type-I interferon responses. However, the role of Orf9b in brain inflammation remains to be elucidated. We found that Orf9b overexpression in microglial cell line BV2 promotes cytokine release of the proinflammatory cytokine IL-6 after the lipopolysaccharide (LPS) treatment. Recent interactome analyses revealed that Orf9b interacts with microtubule affinity-regulating kinase (MARK) 2. We found that MARK2 and Orf9b colocalize at mitochondria. As observed with Orf9b overexpression, MARK2 knockdown via RNAi enhanced IL-6 release in BV2 treated with LPS. We also found that co-expression of Orf9b suppressed the MARK2 kinase activity. These results suggest that MARK2 negatively regulates immune responses in microglia, and ORF9b over activates it via suppression of MARK2. The sustained overactivation of microglia may cause neuronal damage by releasing cytotoxic molecules, including proinflammatory cytokines. Thus, our results suggest that MARK2 dysregulation and overactivation of microglia may contribute to brain damages by SARS-CoV-2.

2021/9/30　11:00～12:00　ZOOM 若手道場 WD2-2 ATP感受性カリウムチャネル Kir6.1の扁桃体依存性恐怖記憶の形成における役割 Abnormal amygdala-dependent fear memory in Kir6.1 heterozygous mice ^○稲垣良¹, 森口茂樹¹, 福永浩司² 1.未記入, 2.Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University ^○Ryo Inagaki¹, 茂樹森口¹, 浩司福永² 1.Research Center for Pharmaceutical Development, Graduate School of Pharmaceutical Sciences, Tohoku University, 2.Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University ATP-sensitive K+ channels are predominantly expressed in the brain and consist of four identical inward-rectifier potassium ion channel subunits (Kir6.1 or Kir6.2) and four identical sulfonylurea receptor subunits. Here, we report that Kir6.1 heterozygous (Kir6.1+/-) mice exhibit impaired amygdala-dependent cued-fear memory. Our previous reports exhibited the enhanced anxiety-like behavior and amygdala-dependent fear memory in chronic corticosterone-treated (CORT) mice. In the present study, we observed decreased expression levels of Kir6.1 protein in the lateral amygdala (LA) of CORT mice. Similar to CORT mice, Kir6.1+/- mice showed impairment of fear-related behaviors assessed by elevated-plus maze, light and dark, open-field and marble burying tasks. In addition, Kir6.1+/- mice were abnormal in tone-induced fear memory but normal in contextual memory. In immunohistochemical analyses, Kir6.1+/- mice revealed a significant increase in the number of c-Fos positive cells in the LA at 1 and 2 hours after fear-induced tone stimuli. Furthermore, enhancement of CaM kinase II or ERK activities in the LA were observed in Kir6.1+/- mice by immunoblot analyses. In concordance with the enhanced amygdala-dependent fear memory, Kir6.1+/- mice significantly ehnance long-term potentiation (LTP) relative to WT mice in the LA. Thus, the increased CaM kinase II activity and in turn enhancement of LTP induction likely account for the dysregulation of amygdala-dependent fear memory in Kir6.1+/- mice.		2021/9/30　11:00～12:00　ZOOM 若手道場 WD2-3 カンナビノイド受容体CB1のミトコンドリアダイナミクスにおける役割 The role of cannabinoid CB1 receptor in mitochondrial dynamics ^○森一明¹, Toru Asahi^1,2,3, Kosuke Kataoka³ 1.未記入, 2.Research Organization for Nano & Life Innovation, Waseda University, 3.Comprehensive Research Organization, Waseda University ^○Kazuaki Mori¹, Toru Asahi^1,2,3, Kosuke Kataoka³ 1.Graduate School of Advanced Science and Engineering, Waseda University, 2.Research Organization for Nano & Life Innovation, Waseda University, 3.Comprehensive Research Organization, Waseda University Cannabinoid receptor type 1 (CB1), the most abundant G-protein coupled receptor in the brain, contributes to the homeostatic defense against brain aging. Recent studies have suggested that CB1 can regulate memory processes via modulation of mitochondrial energy metabolism. Mitochondrial dysfunction is one of the most important hallmarks of aging, which is caused by disrupted mitochondrial quality controls (MQCs), for example, mitochondrial fission/fusion regulation and mitochondrial autophagy (mitophagy). Various levels of MQCs cooperate to maintain mitochondrial health to sustain energy homeostasis in the cell. We previously found that CB1 is involved in mitochondrial dynamics and mitophagy specifically in the hippocampal neurons of aged mice. Although CB1 is thought to maintain neuronal integrity most likely through MQCs, its molecular mechanism remains still unknown. Here, we aim to examine how CB1 regulates neuronal MQCs. To this end, we pharmacologically modulated CB1 activity in human neuroblastoma cell line SH-SY5Y. Rimonabant, a selective inverse agonist of CB1 receptor, induced the mitochondrial fragmentation in a dose-dependent manner, whereas ACEA, a selective agonist, had no effect, which is an opposite result expected by the previous observation in aged mice. In this talk, we will evaluate the expression and activity of several regulators of mitochondrial morphology including dynamin related protein 1. In addition, we will further present and discuss subcellular localization-dependent effect of CB1 with transcriptomic data.