Liu Gang, Liu Qingbai, Yan Bin, Zhu Ziqiang, Xu Yaozeng
Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, China.
Department of Orthopaedics, The Second Affiliated Hospital of Xuzhou Medical University, Xuzhou, China.
Front Pharmacol. 2021 Jan 29;11:617270. doi: 10.3389/fphar.2020.617270. eCollection 2020.
Osteoarthritis (OA), the most common form of arthritis, is a very common joint disease that often affects middle-aged to elderly people. However, current treatment options for OA are predominantly palliative. Thus, understanding its pathological process and exploring its potential therapeutic approaches are of great importance. Rat chondrocytes were isolated and exposed to hydrogen peroxide (HO) to mimic OA. The effects of HO on ubiquitin-specific protease 7 (USP7) expression, reactive oxygen species (ROS) levels, proliferation, inflammatory cytokine release, and pyroptosis were measured. USP7 was knocked down (KD) or overexpressed to investigate the role of USP7 in OA. Co-immunoprecipitation (Co-IP) was used to study the interaction between USP7 and NAD(P)H oxidases (NOX)4 as well as NOX4 ubiquitination. NOX4 inhibitor was applied to study the involvement of NOX4 in USP7-mediated OA development. USP7 inhibitor was given to OA animals to further investigate the role of USP7 in OA . Moreover, HO treatment significantly increased USP7 expression, enhanced ROS levels, and inhibited proliferation in rat chondrocytes. The overexpression of USP7 enhanced pyroptosis, ROS production, interleukin (IL)-1β and IL-18 levels, and the expression level of NLRP3, GSDMD-N, active caspase-1, pro-caspase-1, matrix metalloproteinases (MMP) 1, and MMP13, which was abolished by ROS inhibition. The USP7 KD protected rat chondrocytes against HO-induced injury. Co-IP results showed that USP7 interacted with NOX4, and USP7 KD enhanced NOX4 ubiquitinylation. The inhibition of NOX4 blocked the pro-OA effect of USP7. Moreover, the USP7 inhibitor given to OA animals suppressed OA . USP7 inhibited NOX4 ubiquitination for degradation which leads to elevated ROS production. ROS subsequently activates NLPR3 inflammasome, leading to enhanced production of IL-1β and IL-18, GSDMD-N-dependent pyroptosis, and extracellular matrix remodeling. Thus, UPS7 contributes to the progression of OA via NOX4/ROS/NLPR3 axis.
骨关节炎(OA)是最常见的关节炎形式,是一种非常常见的关节疾病,常影响中老年人。然而,目前OA的治疗选择主要是姑息性的。因此,了解其病理过程并探索其潜在的治疗方法非常重要。分离大鼠软骨细胞并使其暴露于过氧化氢(HO)以模拟OA。检测HO对泛素特异性蛋白酶7(USP7)表达、活性氧(ROS)水平、增殖、炎性细胞因子释放和细胞焦亡的影响。敲低(KD)或过表达USP7以研究USP7在OA中的作用。采用免疫共沉淀(Co-IP)研究USP7与NAD(P)H氧化酶(NOX)4之间的相互作用以及NOX4的泛素化。应用NOX4抑制剂研究NOX4在USP7介导的OA发展中的作用。给OA动物给予USP7抑制剂以进一步研究USP7在OA中的作用。此外,HO处理显著增加USP7表达,提高ROS水平,并抑制大鼠软骨细胞增殖。USP7的过表达增强了细胞焦亡、ROS产生、白细胞介素(IL)-1β和IL-18水平以及NLRP3、GSDMD-N、活性半胱天冬酶-1、前半胱天冬酶-1、基质金属蛋白酶(MMP)1和MMP13的表达水平,而ROS抑制可消除这些作用。USP7 KD保护大鼠软骨细胞免受HO诱导的损伤。Co-IP结果显示USP7与NOX4相互作用,USP7 KD增强了NOX4的泛素化。抑制NOX4可阻断USP7的促OA作用。此外,给OA动物给予USP7抑制剂可抑制OA。USP7抑制NOX4的泛素化降解,导致ROS产生增加。ROS随后激活NLPR3炎性小体,导致IL-1β和IL-18产生增加、GSDMD-N依赖性细胞焦亡以及细胞外基质重塑。因此,UPS7通过NOX4/ROS/NLPR3轴促进OA的进展。