Department of Rheumatology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Department of Traditional Chinese Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Front Immunol. 2018 Apr 12;9:749. doi: 10.3389/fimmu.2018.00749. eCollection 2018.
Fibroblast-like synoviocytes (FLS) exhibit a unique aggressive phenotype in rheumatoid arthritis (RA). Increased FLS migration and subsequent invasion of the extracellular matrix are essential to joint destruction in RA. Our previous research reported that transcription factor SOX5 was highly expressed in RA-FLS. Here, the effects of SOX5 in RA-FLS migration and invasion will be investigated.
The migration and invasion of RA-FLS were evaluated using a transwell chamber assay. The expression of several potential SOX5-targeted genes, including matrix metalloproteinases (MMP-1, 2, 3 and 9), chemokines (CCL4, CCL2, CCR5 and CCR2), and pro-inflammatory cytokines (TNF-α and IL-6), were examined in RA-FLS using SOX5 gain- and loss-of-function study. The molecular mechanisms of SOX5-mediated MMP-9 expressions were assayed by luciferase reporter gene and chromatin immunoprecipitation (ChIP) studies. The effect of SOX5 on FLS migration and invasion was examined using collagen-induced arthritis (CIA) in DBA/1J mice.
Knockdown SOX5 decreased lamellipodium formation, migration, and invasion of RA-FLS. The expression of MMP-9 was the only gene tested to be concomitantly affected by silencing or overexpressing SOX5. ChIP assay revealed that SOX5 was bound to the MMP-9 promoter in RA-FLS. The overexpression of SOX5 markedly enhanced the MMP-9 promoter activity, and specific deletion of a putative SOX5-binding site in MMP-9 promoter diminished this promoter-driven transcription in FLS. Locally knocked down SOX5 inhibited MMP-9 expression in the joint tissue and reduced pannus migration and invasion into the cartilage in CIA mice.
SOX5 plays a novel role in mediating migration and invasion of FLS in part by regulating MMP-9 expression in RA.
成纤维样滑膜细胞（FLS）在类风湿关节炎（RA）中表现出独特的侵袭表型。FLS 的迁移增加和随后对细胞外基质的侵袭对于 RA 中的关节破坏至关重要。我们之前的研究报道转录因子 SOX5 在 RA-FLS 中高度表达。在这里，将研究 SOX5 对 RA-FLS 迁移和侵袭的影响。
使用 Transwell 室测定评估 RA-FLS 的迁移和侵袭。使用 SOX5 功能获得和功能丧失研究，在 RA-FLS 中检查几种潜在的 SOX5 靶向基因（包括基质金属蛋白酶（MMP-1、2、3 和 9）、趋化因子（CCL4、CCL2、CCR5 和 CCR2）和促炎细胞因子（TNF-α 和 IL-6）的表达。通过荧光素酶报告基因和染色质免疫沉淀（ChIP）研究检测 SOX5 介导 MMP-9 表达的分子机制。使用 DBA/1J 小鼠胶原诱导性关节炎（CIA）研究 SOX5 对 FLS 迁移和侵袭的影响。
敲低 SOX5 减少了 RA-FLS 的片状伪足形成、迁移和侵袭。在所测试的基因中，只有 MMP-9 的表达被同时受到沉默或过表达 SOX5 的影响。ChIP 测定显示 SOX5 与 RA-FLS 中的 MMP-9 启动子结合。SOX5 的过表达显着增强了 MMP-9 启动子活性，并且 MMP-9 启动子中假定的 SOX5 结合位点的特异性缺失降低了 FLS 中的这种启动子驱动转录。局部敲低 SOX5 抑制了 CIA 小鼠关节组织中 MMP-9 的表达，并减少了滑膜向软骨的迁移和侵袭。
SOX5 通过调节 RA 中 MMP-9 的表达在介导 FLS 的迁移和侵袭中发挥新的作用。
