PMID- 35927640 OWN - NLM STAT- MEDLINE DCOM- 20220808 LR - 20220809 IS - 1471-2202 (Electronic) IS - 1471-2202 (Linking) VI - 23 IP - 1 DP - 2022 Aug 4 TI - High-frequency repetitive transcranial magnetic stimulation (rTMS) protects against ischemic stroke by inhibiting M1 microglia polarization through let-7b-5p/HMGA2/NF-kappaB signaling pathway. PG - 49 LID - 10.1186/s12868-022-00735-7 [doi] LID - 49 AB - BACKGROUND: Microglia assume opposite phenotypes in response to ischemic brain injury, exerting neurotoxic and neuroprotective effects under different ischemic stages. Modulating M1/M2 polarization is a potential therapy for treating ischemic stroke. Repetitive transcranial magnetic stimulation (rTMS) held the capacity to regulate neuroinflammation and astrocytic polarization, but little is known about rTMS effects on microglia. Therefore, the present study aimed to examine the rTMS influence on microglia polarization and the underlying possible molecular mechanisms in ischemic stroke models. METHODS: Previously reported 10 Hz rTMS protocol that regulated astrocytic polarization was used to stimulate transient middle cerebral artery occlusion (MCAO) rats and oxygen and glucose deprivation/reoxygenation (OGD/R) injured BV2 cells. Specific expression levels of M1 marker iNOS and M2 marker CD206 were measured by western blotting and immunofluorescence. MicroRNA expression changes detected by high-throughput second-generation sequencing were validated by RT-PCR and fluorescence in situ hybridization (FISH) analysis. Dual-luciferase report assay and miRNA knock-down were applied to verify the possible mechanisms regulated by rTMS. Microglia culture medium (MCM) from different groups were collected to measure the TNF-alpha and IL-10 concentrations, and detect the influence on neuronal survival. Finally, TTC staining and modified Neurological Severity Score (mNSS) were used to determine the effects of MCM on ischemic stroke volume and neurological functions. RESULTS: The 10 Hz rTMS inhibited ischemia/reperfusion induced M1 microglia and significantly increased let-7b-5p level in microglia. HMGA2 was predicted and proved to be the target protein of let-7b-5p. HMGA2 and its downstream NF-kappaB signaling pathway were inhibited by rTMS. Microglia culture medium (MCM) collected from rTMS treated microglia contained lower TNF-alpha concentration but higher IL-10 concentration than no rTMS treated MCM, reducing ischemic volumes and neurological deficits of MCAO mice. However, knockdown of let-7b-5p by antagomir reversed rTMS effects on microglia phenotype and associated HMGA/NF-kappaB activation and neurological recovery. CONCLUSION: High-frequency rTMS could alleviate ischemic stroke injury through inhibiting M1 microglia polarization via regulating let-7b-5p/HMGA2/NF-kappaB signaling pathway in MCAO models. CI - (c) 2022. The Author(s). FAU - Hong, Ye AU - Hong Y AD - Department of Neurology, Nanjing First Hospital, Nanjing Medical University, 68# Changle Road, Nanjing, 210029, Jiangsu, China. FAU - Lyu, Jinfeng AU - Lyu J AD - Department of Neurology, Nanjing First Hospital, Nanjing Medical University, 68# Changle Road, Nanjing, 210029, Jiangsu, China. FAU - Zhu, Lin AU - Zhu L AD - Department of Neurology, Nanjing First Hospital, Nanjing Medical University, 68# Changle Road, Nanjing, 210029, Jiangsu, China. FAU - Wang, Xixi AU - Wang X AD - Department of Neurology, Nanjing First Hospital, Nanjing Medical University, 68# Changle Road, Nanjing, 210029, Jiangsu, China. FAU - Peng, Mengna AU - Peng M AD - Department of Neurology, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, Jiangsu, China. FAU - Chen, Xiangliang AU - Chen X AD - Department of Neurology, Nanjing First Hospital, Nanjing Medical University, 68# Changle Road, Nanjing, 210029, Jiangsu, China. FAU - Deng, Qiwen AU - Deng Q AD - Department of Neurology, Nanjing First Hospital, Nanjing Medical University, 68# Changle Road, Nanjing, 210029, Jiangsu, China. FAU - Gao, Jie AU - Gao J AD - Department of Neurology, Nanjing First Hospital, Nanjing Medical University, 68# Changle Road, Nanjing, 210029, Jiangsu, China. FAU - Yuan, Zhenhua AU - Yuan Z AD - Department of Neurology, Nanjing First Hospital, Nanjing Medical University, 68# Changle Road, Nanjing, 210029, Jiangsu, China. FAU - Wang, Di AU - Wang D AD - Department of Neurology, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, Jiangsu, China. FAU - Xu, Gelin AU - Xu G AD - Department of Neurology, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, Jiangsu, China. FAU - Xu, Mengyi AU - Xu M AD - Department of Neurology, Nanjing First Hospital, Nanjing Medical University, 68# Changle Road, Nanjing, 210029, Jiangsu, China. xumengyiabc@163.com. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20220804 PL - England TA - BMC Neurosci JT - BMC neuroscience JID - 100966986 RN - 0 (NF-kappa B) RN - 0 (Tumor Necrosis Factor-alpha) RN - 130068-27-8 (Interleukin-10) SB - IM MH - Animals MH - *Brain Ischemia/metabolism/therapy MH - In Situ Hybridization, Fluorescence MH - Infarction, Middle Cerebral Artery MH - Interleukin-10/metabolism MH - *Ischemic Stroke/therapy MH - Mice MH - Microglia MH - NF-kappa B/metabolism MH - Rats MH - Signal Transduction MH - Transcranial Magnetic Stimulation MH - Tumor Necrosis Factor-alpha/metabolism PMC - PMC9351069 OTO - NOTNLM OT - HMGA2 OT - Ischemic stroke OT - Let-7b-5p OT - Microglia polarization OT - NF-kappaB OT - rTMS COIS- The authors declare that they have no competing interests. EDAT- 2022/08/05 06:00 MHDA- 2022/08/09 06:00 PMCR- 2022/08/04 CRDT- 2022/08/04 23:43 PHST- 2022/01/05 00:00 [received] PHST- 2022/07/28 00:00 [accepted] PHST- 2022/08/04 23:43 [entrez] PHST- 2022/08/05 06:00 [pubmed] PHST- 2022/08/09 06:00 [medline] PHST- 2022/08/04 00:00 [pmc-release] AID - 10.1186/s12868-022-00735-7 [pii] AID - 735 [pii] AID - 10.1186/s12868-022-00735-7 [doi] PST - epublish SO - BMC Neurosci. 2022 Aug 4;23(1):49. doi: 10.1186/s12868-022-00735-7.