Department of Neurology, Yantian District People's Hospital, Shenzhen, China.
Department of Radiology, Yantian District People's Hospital, Shenzhen, China.
Immun Inflamm Dis. 2023 Jan;11(1):e756. doi: 10.1002/iid3.756.
The inflammation mediated by microglial cells plays an important role in the process of neurodegenerative diseases. Recent evidence indicates that semaphorin 7A (SEMA7A) is implicated in various neurodegenerative diseases, but whether it plays a role in Parkinson's disease (PD) remains unclear.
In this study, 1.0 mmol/L 1-methyl-4-phenylpyridinium (MPP )-stimulated mouse microglia (BV2) cells were used as an in vitro model of PD. The expression of SEMA7A was detected by quantitative polymerase chain reaction. Cell Counting Kit-8 and apoptosis kits were used to analyze the viability and apoptosis of BV-2 cells. The content of IL-6, IL-β, and tumor necrosis factor-α was determined by ELISA (enzyme-linked immunosorbent assay) kit. Western blot was used to detect the protein expression level of the inducible NO synthase and cyclooxygenase-2.
Our findings indicated that SEMA7A expression in BV2 cells was upregulated after MPP stimulation. Knockdown of SEMA7A promoted cell viability while it inhibited apoptosis and the expression of proinflammatory enzymes and proinflammatory cytokines. Silencing SEMA7A-induced peroxisome proliferator-activated receptor-gamma (PPAR-γ) activation and mitogen-activated protein kinase (MAPK) signaling pathway inactivation. Furthermore, a PPAR-γ inhibitor and an MAPK activator promoted the effect of MPP on cell viability, apoptosis, and inflammation of BV2 cells; what is more, the PPAR-γ inhibitor and MAPK activator blocked the inhibitory effect of SEMA7A downregulation on MPP -induced injury.
In general, knockdown of SEMA7A inhibits MPP -induced BV2 cell apoptosis and inflammation via PPAR-γ activation and MAPK inactivation, which may provide a new therapy target for PD.
小胶质细胞介导的炎症在神经退行性疾病的过程中起着重要作用。最近的证据表明，神经纤毛蛋白 7A（SEMA7A）与各种神经退行性疾病有关，但它是否在帕金森病（PD）中起作用尚不清楚。
本研究采用 1.0mmol/L 1-甲基-4-苯基吡啶（MPP）刺激的小鼠小胶质细胞（BV2）细胞作为 PD 的体外模型。通过定量聚合酶链反应检测 SEMA7A 的表达。细胞计数试剂盒-8 和凋亡试剂盒用于分析 BV-2 细胞的活力和凋亡。酶联免疫吸附试验（ELISA）试剂盒测定白细胞介素-6（IL-6）、白细胞介素-β（IL-β）和肿瘤坏死因子-α（TNF-α）的含量。Western blot 检测诱导型一氧化氮合酶和环氧化酶-2 的蛋白表达水平。
我们的研究结果表明，MPP 刺激后 BV2 细胞中 SEMA7A 的表达上调。SEMA7A 敲低促进细胞活力，同时抑制细胞凋亡和促炎酶和促炎细胞因子的表达。沉默 SEMA7A 诱导过氧化物酶体增殖物激活受体-γ（PPAR-γ）激活和丝裂原激活蛋白激酶（MAPK）信号通路失活。此外，PPAR-γ 抑制剂和 MAPK 激活剂促进了 MPP 对 BV2 细胞活力、凋亡和炎症的影响；更重要的是，PPAR-γ 抑制剂和 MAPK 激活剂阻断了 SEMA7A 下调对 MPP 诱导损伤的抑制作用。
总之，SEMA7A 敲低通过 PPAR-γ 激活和 MAPK 失活抑制 MPP 诱导的 BV2 细胞凋亡和炎症，这可能为 PD 提供新的治疗靶点。
