Department of Psychiatry, Chaohu Hospital of Anhui Medical University, Hefei, Anhui Province, China; Department of Psychiatry, Anhui Psychiatric Center, Anhui Medical University, Hefei, Anhui Province, China.
Key Laboratory of Non-coding RNA Transformation Research of Anhui Higher Education Institutes, Wannan Medical College, Wuhu, Anhui Province, China; Department of Neurology, The First Affiliated Hospital of Wannan Medical College, Wuhu, Anhui Province, China.
Brain Res Bull. 2021 Dec;177:31-38. doi: 10.1016/j.brainresbull.2021.09.006. Epub 2021 Sep 14.
The kinase MST4 limits inflammatory responses through direct phosphorylation of the adaptor TRAF6. TRAF6 interacts with NLRP3 to promote the activation of NLRP3 inflammasome. However, the role of MST4 in neuroinflammation after intracerebral hemorrhage (ICH) and how it interacts with NLRP3 inflammasome remain unclear.
Mice were administered MST4 AAV four weeks before collagenase-induced ICH. ICH mice received either hesperadin (MST4 selective inhibitor), or MCC950 (NLRP3 inflammasome selective inhibitor). Neurological deficits and brain water content were assessed. Western blot and immunofluorescence were performed to evaluate the proteins content and localization in MST4/NLRP3 signaling pathway.
The expression of endogenous MST4 and NLRP3 was increased after ICH compared to sham group. MST4 and NLRP3 were respectively colocalized in microglia. Upregulation of MST4 gene inhibited the activation of NLRP3 inflammasome, the release of IL-1β and TNF-α, and significantly improved brain edema and neurological deficits. Hesperadin pretreatment inhibited the expression of MST4 and increased the expression of NLRP3 inflammasome-mediated proteins, which aggravated neurological deficits and cerebral edema. MCC950 markedly alleviated neurological deficits and brain edema but had no effect on the expression of MST4 protein.
MST4 alleviates inflammatory progression and brain injury in ICH mice possibly by inhibiting NLRP3 inflammasome activation.
激酶 MST4 通过直接磷酸化衔接蛋白 TRAF6 来限制炎症反应。TRAF6 与 NLRP3 相互作用，促进 NLRP3 炎性小体的激活。然而，MST4 在脑出血（ICH）后的神经炎症中的作用以及它与 NLRP3 炎性小体的相互作用仍不清楚。
在胶原酶诱导的 ICH 前四周，用 MST4 AAV 处理小鼠。ICH 小鼠接受 hesperadin（MST4 选择性抑制剂）或 MCC950（NLRP3 炎性小体选择性抑制剂）治疗。评估神经功能缺损和脑含水量。通过 Western blot 和免疫荧光法评估 MST4/NLRP3 信号通路中的蛋白质含量和定位。
与假手术组相比，ICH 后内源性 MST4 和 NLRP3 的表达增加。MST4 和 NLRP3 分别在小胶质细胞中共定位。MST4 基因的上调抑制了 NLRP3 炎性小体的激活、IL-1β 和 TNF-α 的释放，并显著改善了脑水肿和神经功能缺损。hesperadin 预处理抑制了 MST4 的表达，并增加了 NLRP3 炎性小体介导的蛋白质的表达，这加重了神经功能缺损和脑水肿。MCC950 显著减轻了神经功能缺损和脑水肿，但对 MST4 蛋白的表达没有影响。
MST4 通过抑制 NLRP3 炎性小体的激活，减轻 ICH 小鼠的炎症进展和脑损伤。
