The direct binding of collagen XVII and collagen IV is disrupted by pemphigoid autoantibodies
The direct binding of collagen XVII and collagen IV is disrupted by pemphigoid autoantibodies
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DOI：
10.1038/s41374-018-0113-9
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发表时间：
2019-01-01
影响因子：
5
通讯作者：
Shimizu, Hiroshi
中科院分区：
文献类型：
--
作者：
Kamaguchi, Mayumi;Iwata, Hiroaki;Shimizu, Hiroshi
基底膜区 (BMZ) 由半桥粒和细胞外基质 (ECM) 构成，其中包括 IV 型胶原 (COL4)。半桥粒是包含胶原蛋白 XVII (COL17) 的多蛋白复合物。 BMZ 蛋白可靶向治疗自身免疫性表皮下水疱疾病，例如靶向 COL17 的类天疱疮。类天疱疮的起泡机制尚未完全阐明，特别是粘膜类天疱疮（MMP），主要影响粘膜。在这项研究中，我们表明类天疱疮的口腔病变可能归因于自身抗体抑制蛋白质-蛋白质相互作用。通过免疫沉淀，我们发现 COL17 直接与正常人角质形成细胞和正常人口腔角质形成细胞中的 COL4 结合。特别是，COL17 的 C 末端是口腔角质形成细胞中 COL4 的结合位点。通过蛋白质-蛋白质结合测定确定 COL17 上的精确 COL4 结合区域为 C 末端氨基酸 Gly(1175) 至 (Asp1340)。识别 C 末端的 MMP-IgG 或 mAb 阻碍口腔角质形成细胞中 COL17 与 COL4 的相互作用。此外，针对 C 末端的 mAb 处理显着降低了角质形成细胞对 COL4 包被板的粘附强度。此外，与 BP 相比，MMP 中病变周围的炎症浸润明显较少。这些结果表明，靶向 C 末端的类天疱疮 IgG 在口腔粘膜水疱形成中发挥致病作用，可抑制蛋白质相互作用，同时减少炎症。
The basement membrane zone (BMZ) is framed by hemidesmosomes and extracellular matrix (ECM) including collagen IV (COL4). Hemidesmosomes are multiprotein complexes that include collagen XVII (COL17). BMZ proteins can be targeted in autoimmune subepidermal blistering diseases, e.g., pemphigoid targeting COL17. The blistering mechanisms in pemphigoid have not been fully elucidated, especially in mucous membrane pemphigoid (MMP), which mainly affects the mucosa. In this study, we showed that oral lesions in pemphigoid may be attributed to the inhibition of protein-protein interactions by autoantibodies. Using immunoprecipitation, we revealed that COL17 directly binds to COL4 in normal human keratinocytes and normal human oral keratinocytes. In particular, the C-terminus of COL17 is binding site to COL4 in oral keratinocytes. The precise COL4-binding region on COL17 was determined by protein-protein binding assay to be from amino acid Gly(1175) to (Asp1340) on the C-terminus. MMP-IgG or mAb recognizing the C-terminus hindered the interaction of COL17 with COL4 in oral keratinocytes. Furthermore, keratinocyte adhesion strength to COL4-coated plates was significantly reduced by the treatment of mAb against the C-terminus. In addition, the inflammatory infiltrates around perilesions were significantly less in MMP compared to BP. These results indicate that pemphigoid IgG targeting the C-terminus plays a pathogenic role in blister formation in the oral mucosa to inhibit protein interactions with less inflammation.