Fan Lieying, Zong Ming, Gong Ruhan, He Dongyi, Li Niu, Sun Li Shan, Ye Qin, Yu Shanshan
Department of Clinical Laboratory, Shanghai East Hospital, School of Medicine, Tong Ji University, 150 Ji Mo Road, Shanghai 200120, PR China.
Department of Rheumatology, Guanghua Integrative Medicine Hospital, 540 Xin Hua Road, Shanghai 200052, PR China.
Int J Biol Sci. 2017 Feb 25;13(3):358-366. doi: 10.7150/ijbs.16879. eCollection 2017.
Rheumatoid arthritis (RA) is characterized by synovial lining hyperplasia, which involves abnormal growth of fibroblast-like synoviocytes (FLSs). This study aimed to investigate the function and molecular mechanism of peptidylarginine deiminase type 4 (PADI4) in FLSs isolated from RA patients (RA-FLSs). FLSs were isolated from RA patients and transfected with small interfering RNAs (siRNAs) or PADI4 overexpression plasmid. FLSs were treated by Adriamycin (ADR) to induce apoptosis, and apoptotic cells were detected by flow cytometry. The expression of PADI4, p53 and p21 was detected by qRT-PCR and Western blot analysis. The recruitment of PADI4 and histone H3 arginine modifications to p21 promoter was measured by chromatin immunoprecipitation. The results showed that knockdown of PADI4 promoted the apoptosis of RA-FLSs and the expression of p53 and p21. Ectopic expression of PADI4 inhibited ADR-induced apoptosis of RA-FLSs, and down-regulated the expression of p53 and p21. In RA-FLSs, global H3 citrullination (CitH3) and H3 arginine 17 methylation levels were dynamically changed by PADI4 and ADR treatment. PADI4 and H3 could bind p21 promoter region to regulate p21 expression. In conclusion, PADI4 contributes to the pathogenesis of RA by protecting FLSs from apoptosis. PADI4 suppresses p21 transcription through altering histone H3 arginine modifications on p21 promoter region. Our study provides new insight into the anti-apoptotic role of PADI4 in RA development.
类风湿关节炎（RA）的特征是滑膜衬里增生，这涉及成纤维细胞样滑膜细胞（FLS）的异常生长。本研究旨在探讨肽基精氨酸脱亚氨酶4（PADI4）在从RA患者分离的FLS（RA-FLS）中的功能及分子机制。从RA患者中分离出FLS，并转染小干扰RNA（siRNA）或PADI4过表达质粒。用阿霉素（ADR）处理FLS以诱导凋亡，通过流式细胞术检测凋亡细胞。通过qRT-PCR和蛋白质印迹分析检测PADI4、p53和p21的表达。通过染色质免疫沉淀测定PADI4和组蛋白H3精氨酸修饰对p21启动子的募集。结果显示，敲低PADI4可促进RA-FLS的凋亡以及p53和p21的表达。PADI4的异位表达抑制ADR诱导的RA-FLS凋亡，并下调p53和p21的表达。在RA-FLS中，PADI4和ADR处理可动态改变整体H3瓜氨酸化（CitH3）和H3精氨酸17甲基化水平。PADI4和H3可结合p21启动子区域以调节p21表达。总之，PADI4通过保护FLS免于凋亡而促进RA的发病机制。PADI4通过改变p21启动子区域的组蛋白H3精氨酸修饰来抑制p21转录。我们的研究为PADI4在RA发展中的抗凋亡作用提供了新的见解。
