Rheumatoid arthritis (RA) is a chronic, progressive autoimmune disease with a complex pathogenesis that has not yet been fully elucidated, and T-cell pyroptosis is an important pathogenetic factor in RA. This study aimed to investigate the role of endoplasmic reticulum aminopeptidase 2 (ERAP2) in the pyroptosis of CD4+ T cells in RA and the specific molecular mechanism. Peripheral venous blood was collected from human subjects, and CD4+ T cells were isolated and activated to measure the level of pyroptosis and ERAP2 expression. Pyroptosis levels were assessed using immunofluorescence, flow cytometry, qRT-PCR, and Western blotting. Changes in pyroptosis levels were observed upon knockdown or overexpression of ERAP2. To detect activated Caspase-1 in tissues, chimeric mice were engrafted with human synovial tissue and reconstituted with human CD4+ T cells. CD4 + T cells were treated with GLI1 antagonists and SMO receptor agonists to detect changes in pyroptosis levels. CD4+ T cell levels undergoing pyroptosis were found to be elevated in the blood and synovium of RA patients. The gene and protein expression of ERAP2 were significantly higher in CD4+ T cells from RA patients. Deletion of ERAP2 suppressed pyroptosis of these cells, attenuated the activation of Caspase-1 in tissue T cells, and reduced tissue inflammatory responses. Reciprocally, overexpression of ERAP2 triggered inflammasome assembly, activated Caspase-1, and induced pyroptosis in CD4+ T cells. Mechanistically, ERAP2 inhibits the Hedgehog signaling pathway and upregulates the expression of nucleotide-binding oligomerization segment-like receptor family 3(NLRP3), cleaved Caspase-1, and Gasdermin D to promote pyroptosis in CD4+ T cells. Taken together, our results identify a novel mechanism by which ERAP2 regulates RA development and document the effect of the ERAP2/Hedgehog signaling axis on pyroptosis of CD4+ T cells from RA patients.

中文翻译：

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内质网氨肽酶 2 调节类风湿性关节炎中 CD4+ T 细胞焦亡

类风湿性关节炎（RA）是一种慢性、进行性自身免疫性疾病，其发病机制复杂且尚未完全阐明，T细胞焦亡是RA的重要发病因素。本研究旨在探讨内质网氨肽酶2（ERAP2）在RA CD4+ T细胞焦亡中的作用及其具体分子机制。采集人类受试者的外周静脉血，分离并激活CD4+T细胞以测量细胞焦亡和ERAP2表达水平。使用免疫荧光、流式细胞术、qRT-PCR 和蛋白质印迹法评估焦亡水平。在 ERAP2 敲低或过表达后观察到细胞焦亡​​水平的变化。为了检测组织中激活的 Caspase-1，嵌合小鼠被植入人类滑膜组织并用人类 CD4+ T 细胞重建。用GLI1拮抗剂和SMO受体激动剂处理CD4+T细胞以检测细胞焦亡水平的变化。研究发现，RA 患者血液和滑膜中发生细胞焦亡的 CD4+ T 细胞水平升高。RA 患者的 CD4+ T 细胞中 ERAP2 基因和蛋白表达显着升高。ERAP2 的缺失抑制了这些细胞的焦亡，减弱了组织 T 细胞中 Caspase-1 的激活，并减少了组织炎症反应。相反，ERAP2 的过度表达会触发炎症小体组装，激活 Caspase-1，并诱导 CD4+ T 细胞焦亡。从机制上讲，ERAP2 抑制 Hedgehog 信号通路并上调核苷酸结合寡聚化片段样受体家族 3 (NLRP3)、cleaved Caspase-1 和 Gasdermin D 的表达，从而促进 CD4+ T 细胞焦亡。综上所述，我们的结果确定了 ERAP2 调节 RA 发展的新机制，并记录了 ERAP2/Hedgehog 信号轴对 RA 患者 CD4+ T 细胞焦亡的影响。