Department of Anesthesiology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China; Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, Sichuan, China.
Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China; Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, Sichuan, China.
Reprod Biol. 2024 Sep;24(3):100896. doi: 10.1016/j.repbio.2024.100896. Epub 2024 Jun 3.
Activation of the maternal immune system leads to a downstream cascade of proinflammatory events that culminate in the activation of spontaneous uterine contractions, which is associated with preterm birth. Ras-related C3 botulinum toxin substrate 1 (Rac1) is a crucial protein related to cell contraction and inflammation. The main purpose of this study was to explore the role and function of Rac1's regulation of inflammation through in- vivo and in-vitro experiments. Rac1 inhibitor was used in animal model of preterm birth and cells isolated from the uterine tissues of pregnant mice on gestational day 16 were transfected with adenovirus to knockdown or overexpress Rac1 and treated with the Calcium-calmodulin-dependent protein kinase II (CaMKII) inhibitor KN93. The expression of Rac1, uterine contraction-associated proteins (CAPs) (COX-2 and Connexin43), and inflammatory cytokines, were assessed by Western blotting and RTPCR. LPS upregulated Rac1, COX-2 and Connexin43 expression in uterine smooth muscle cells (USMCs). The expression of inflammatory cytokines, COX-2, and Connexin43 was significantly decreased in shRac1-transfected cells compared with cells stimulated with LPS only. Rac1 overexpression led to an increase in the expression of inflammatory cytokines, COX-2, and Connexin43. Furthermore, after Rac1 overexpression, KN93 reduced the expression of uterine contraction-associated proteins and inflammatory cytokines. It is thought that the effect of Rac1 on inflammatory cytokine and contraction-associated protein expression in USMCs is mediated by CaMKII. Rac1 can modulate the expression of contraction-associated proteins and inflammatory cytokines through the CaMKII pathway. Rac1 could be an effective therapeutic target for improving the outcome of preterm birth.
母体免疫系统的激活会导致下游促炎事件级联反应，最终导致自发性子宫收缩的激活，这与早产有关。Ras 相关 C3 肉毒杆菌毒素底物 1（Rac1）是一种与细胞收缩和炎症相关的重要蛋白。本研究的主要目的是通过体内和体外实验探索 Rac1 调节炎症的作用和功能。在早产动物模型中使用 Rac1 抑制剂，并用腺病毒转染妊娠第 16 天的小鼠子宫组织中的细胞，以敲低或过表达 Rac1，并用钙调蛋白依赖性蛋白激酶 II（CaMKII）抑制剂 KN93 处理。通过 Western blot 和 RT-PCR 评估 Rac1、与子宫收缩相关的蛋白（COX-2 和连接蛋白 43）和炎性细胞因子的表达。LPS 上调了子宫平滑肌细胞（USMCs）中 Rac1、COX-2 和连接蛋白 43 的表达。与仅用 LPS 刺激的细胞相比，shRac1 转染的细胞中炎性细胞因子、COX-2 和连接蛋白 43 的表达明显降低。Rac1 的过表达导致炎性细胞因子、COX-2 和连接蛋白 43 的表达增加。此外，在 Rac1 过表达后，KN93 降低了与子宫收缩相关的蛋白和炎性细胞因子的表达。据认为，Rac1 对 USMCs 中炎性细胞因子和收缩相关蛋白表达的影响是通过 CaMKII 介导的。Rac1 可以通过 CaMKII 途径调节收缩相关蛋白和炎性细胞因子的表达。Rac1 可能是改善早产结局的有效治疗靶点。
