Du Jingliang, Liang Xianyang, Wang Denghui, Wang Zhen, Shen Ruile
Department of Neurology, The First Affiliated Hospital, and College of Clinical Medicine of Henan University of Science and Technology, No. 24, Jinghua Road, Jianxi District, Luoyang, 471003, Henan Province, China.
Appl Biochem Biotechnol. 2025 Mar 13. doi: 10.1007/s12010-025-05207-2.
Microglia polarization plays important roles in inflammatory processes after ischemic stroke. This study aimed to explore the mechanism of lysine-specific histone demethylase 4 (KDM4A) in microglia polarization after ischemic stroke. The mouse model was established using middle cerebral artery occlusion/reperfusion (MCAO/R) and the cell model was established by oxygen-glucose deprivation/reperfusion (OGD/R). The neurological deficits and brain tissue injury were evaluated. The biomarkers of microglia were determined. Levels of KDM4A/mouse double minute-2 homolog (MDM2)/C1q/TNF-related protein-3 (CTRP3) were measured. Inflammatory cytokines were quantified. The impact of KDM4A on microglia polarization was assessed. The enrichment of KDM4A or histone 3 lysine 9 trimethylation (H3K9me3) on the MDM2 promoter was analyzed. The ubiquitination and protein levels of CTRP3 after MG132 and cycloheximide treatment were determined. Results showed that KDM4A and MDM2 were upregulated while CTRP3 was downregulated. KDM4A downregulation alleviated neurological dysfunction, rescued motor capacity, reduced inflammatory infiltration, suppressed microglia activation, and promoted M2 polarization. KDM4A inhibited the enrichment of H3K9me3 on the MDM2 promoter, increasing MDM2 expression and downregulating CTRP3 expression via ubiquitination and degradation. MDM2 overexpression or CTRP3 downregulation averted the promotive role of silencing KDM4A in microglia polarization. In conclusion, KDM4A promotes microglia polarization to aggravate ischemic stroke via the MDM2/CTRP3 axis.
小胶质细胞极化在缺血性中风后的炎症过程中起重要作用。本研究旨在探讨赖氨酸特异性组蛋白去甲基化酶4（KDM4A）在缺血性中风后小胶质细胞极化中的作用机制。采用大脑中动脉闭塞/再灌注（MCAO/R）建立小鼠模型，通过氧糖剥夺/再灌注（OGD/R）建立细胞模型。评估神经功能缺损和脑组织损伤。测定小胶质细胞的生物标志物。检测KDM4A/小鼠双微体2同源物（MDM2）/C1q/TNF相关蛋白3（CTRP3）的水平。定量炎症细胞因子。评估KDM4A对小胶质细胞极化的影响。分析KDM4A或组蛋白3赖氨酸9三甲基化（H3K9me3）在MDM2启动子上的富集情况。测定MG132和环己酰亚胺处理后CTRP3的泛素化和蛋白水平。结果显示，KDM4A和MDM2上调，而CTRP3下调。KDM4A下调可减轻神经功能障碍，恢复运动能力，减少炎症浸润，抑制小胶质细胞活化，并促进M2极化。KDM4A抑制H3K9me3在MDM2启动子上的富集，通过泛素化和降解增加MDM2表达并下调CTRP3表达。MDM2过表达或CTRP3下调可消除沉默KDM4A对小胶质细胞极化的促进作用。总之，KDM4A通过MDM2/CTRP3轴促进小胶质细胞极化，加重缺血性中风。
