Medical School of Nantong University, Nantong, Jiangsu Province 226001, China; Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong, Jiangsu, China.
Department of Orthopedics, Affiliated Hospital of Nantong University, Nantong, Jiangsu Province 226001, China.
Int Immunopharmacol. 2021 Oct;99:108006. doi: 10.1016/j.intimp.2021.108006. Epub 2021 Jul 30.
Spinal cord injury (SCI) causes sensation and motion dysfunction. Activation of microglial cells (MCs) in the central nervous system (CNS) is heterogeneous. Heterogeneous types of MCs can produce cytotoxic or neuroprotective effects, secrete proinflammatory or anti-inflammatory factors. The cytotoxic effect of MCs is one of the reasons for secondary damage after SCI. The NLR family pyrin domain containing 3 (NLRP3) inflammasome is a protein that can recognize pathogen-related molecular patterns or host-derived danger signal molecules, responses to microbial infection, and sterile stressors. SCI triggers activation of the NLRP3 inflammasome in the CNS. We investigated the interaction between miR-423-5p and NLRP3 in MCs polarization after SCI. A rat model of SCI was established by a modified version of Allen's method. Spinal samples were adopted for preparation and sequencing of RNA. We screenedapromising microRNA (miR-423-5p) according to the results. Then, we found that NLRP3 was one of the prediction targets of miR-423-5p. By intervening in expression of miR-423-5p and NLRP3, we observed the different polarization of MCs. We employeda dual-luciferase reporter study, proteomics, and transcriptomicsto ascertain the direct targeting relationship between miR-423-5p and NLRP3. MiR-423-5p expression was decreased significantly after SCI in vivo and in vitro. Upregulation of miR-423-5p expression could prevent MCs from lipopolysaccharide-induced M1 polarization. Knockdown of NLRP3 expression could prevent MCs from lipopolysaccharide-induced M1 polarization. MiR-423-5p inhibited MCs polarization to the M1 phenotype by targeting NLRP3.
脊髓损伤（SCI）导致感觉和运动功能障碍。中枢神经系统（CNS）中小胶质细胞（MCs）的激活具有异质性。不同类型的 MCs 可以产生细胞毒性或神经保护作用，分泌促炎或抗炎因子。MCs 的细胞毒性作用是 SCI 后继发性损伤的原因之一。NLR 家族含pyrin 结构域蛋白 3（NLRP3）炎性小体是一种能够识别病原体相关分子模式或宿主来源的危险信号分子、对微生物感染和非生物应激做出反应的蛋白质。SCI 会触发 CNS 中 NLRP3 炎性小体的激活。我们研究了 miR-423-5p 与 SCI 后 MCs 极化中的 NLRP3 之间的相互作用。通过改良的 Allen 法建立 SCI 大鼠模型，采用脊髓样本进行 RNA 的制备和测序。根据结果筛选出一种有前途的 microRNA（miR-423-5p）。然后，我们发现 NLRP3 是 miR-423-5p 的预测靶点之一。通过干预 miR-423-5p 和 NLRP3 的表达，观察到 MCs 的不同极化。我们采用双荧光素酶报告基因研究、蛋白质组学和转录组学来确定 miR-423-5p 和 NLRP3 之间的直接靶向关系。体内和体外 SCI 后 miR-423-5p 的表达明显降低。上调 miR-423-5p 的表达可以防止 MCs 受到脂多糖诱导的 M1 极化。NLRP3 表达的敲低可以防止 MCs 受到脂多糖诱导的 M1 极化。miR-423-5p 通过靶向 NLRP3 抑制 MCs 向 M1 表型极化。
