Department of Rheumatology and Clinical Immunology, Campus Kerckhoff, Justus-Liebig University Giessen, Bad Nauheim, Germany.
Division of Vascular Surgery, Harvey-Vascular-Healthcare Center, Kerckhoff-Klinik GmbH, Bad Nauheim, Germany.
Ann Rheum Dis. 2018 Nov;77(11):1619-1626. doi: 10.1136/annrheumdis-2018-212954. Epub 2018 Jul 6.
Tetraspanins function as membrane adaptors altering cell-cell fusion, antigen presentation, receptor-mediated signal transduction and cell motility via interaction with membrane proteins including other tetraspanins and adhesion molecules such as integrins. CD82 is expressed in several malignant cells and well described as tumour metastasis suppressor. Rheumatoid arthritis (RA) is based on persistent synovial inflammation and joint destruction driven to a large extent by transformed-appearing activated synovial fibroblasts (SF) with an increased migratory potential.
CD82 is upregulated in RA synovial fibroblasts (RASF) compared with osteoarthritis (OA) SF as well as within RA compared with OA synovial lining layer (LL) and the role of CD82 in RASF was evaluated.
CD82 and integrin immunofluorescence was performed. Lentiviral CD82 overexpression and siRNA-mediated knockdown was confirmed (realtime-PCR, Western blot, immunocytochemistry). RASF migration (Boyden chamber, scrape assay), attachment towards plastic/Matrigel, RASF-binding to endothelial cells (EC) and CD82 expression during long-term invasion in the SCID-mouse-model were evaluated.
CD82 was induced by proinflammatory stimuli in SF. In RA-synovium, CD82 was expressed in RASF close to blood vessels, LL, sites of cartilage invasion and colocalised with distinct integrins involved in tumour metastasis suppression but also in RA-synovium by RASF. CD82 overexpression led to reduced RASF migration, cell-matrix and RASF-EC adhesion. Reduced CD82 expression (observed in the sublining) increased RASF migration and matrix adhesion whereas RASF-EC-interaction was reduced. In SCID mice, the presence of CD82 on cartilage-invading RASF was confirmed.
CD82 could contribute to RASF migration to sites of inflammation and tissue damage, where CD82 keeps aggressive RASF on site.
四跨膜蛋白作为膜衔接物，通过与膜蛋白（包括其他四跨膜蛋白和黏附分子，如整合素）相互作用，改变细胞-细胞融合、抗原呈递、受体介导的信号转导和细胞迁移。CD82 在几种恶性细胞中表达，被很好地描述为肿瘤转移抑制因子。类风湿关节炎（RA）是基于持续性滑膜炎症和关节破坏，在很大程度上是由外观转化的激活滑膜成纤维细胞（SF）驱动的，这些细胞具有增强的迁移潜力。
与骨关节炎（OA）SF 相比，RA 滑膜成纤维细胞（RASF）中 CD82 上调，与 OA 滑膜衬里层（LL）相比，RA 中 CD82 上调，评估 CD82 在 RASF 中的作用。
进行 CD82 和整合素免疫荧光。慢病毒 CD82 过表达和 siRNA 介导的敲低得到证实（实时 PCR、Western blot、免疫细胞化学）。评估 RASF 迁移（Boyden 室、划痕试验）、对塑料/Matrigel 的附着、RASF 与内皮细胞（EC）的结合以及在 SCID 小鼠模型中的长期侵袭过程中 CD82 的表达。
SF 中的促炎刺激诱导了 CD82。在 RA 滑膜中，CD82 在靠近血管、LL、软骨侵袭部位的 RASF 中表达，与参与肿瘤转移抑制的特定整合素共定位，但也在 RA 滑膜中由 RASF 表达。CD82 过表达导致 RASF 迁移、细胞-基质和 RASF-EC 黏附减少。下调（在下皮中观察到）增加了 RASF 的迁移和基质黏附，而 RASF-EC 相互作用减少。在 SCID 小鼠中，在侵袭软骨的 RASF 上证实了 CD82 的存在。
CD82 可能有助于 RASF 迁移到炎症和组织损伤部位，在这些部位，CD82 将侵袭性 RASF 保留在原位。
