Razzaque Mohammed S, Foster C Stephen, Ahmed A Razzaque
Department of Dermatology, Harvard Medical School, Boston, Massachusetts, USA.
Invest Ophthalmol Vis Sci. 2003 Apr;44(4):1616-21. doi: 10.1167/iovs.02-0644.
Submucosal fibrosis due to excessive accumulation of collagens is an important histologic feature in the pathogenesis of ocular cicatricial pemphigoid (OCP). Heat shock protein 47 (HSP47), a collagen-binding protein, plays an important role in the biosynthesis of procollagens. In the present study, we examined the role of HSP47 in conjunctival scarring in patients with OCP.
Biopsy specimens of the conjunctiva of 15 patients with OCP and 5 normal subjects were studied for the expression of HSP47, transforming growth factor (TGF)-beta1, type I collagen, and type III collagen. The role of TGF-beta1 on the induction of HSP47 and type I collagen by conjunctival fibroblasts was studied by immunostaining, Western blot analysis, and quantitative real-time PCR.
Compared with the control, increased accumulations of type I and type III collagens were detected by immunohistochemistry in fibrotic conjunctiva of patients with OCP. Weak and sparse expression of HSP47 was detected in the epithelial cells and stromal fibroblasts in control conjunctival tissues. In contrast to the control, the expression of HSP47 was markedly increased in the stromal fibroblasts in conjunctival tissues obtained from patients with OCP, as detected by immunohistochemistry. By quantitative real-time PCR, compared with control conjunctival tissues, a 3.4-fold increase in the expression of HSP47 was noted in the conjunctival tissues obtained from patients with OCP. Similar to conjunctival tissues, fibroblasts isolated from conjunctiva of patients with OCP exhibited 4.8-fold increase in the expression of HSP47, compared with control fibroblasts. When conjunctival fibroblasts were treated with various concentration of TGF-beta1, upregulation in the expression of HSP47 and type I collagen was detected.
This study demonstrated increased expression of HSP47 and TGF-beta1 by conjunctival fibroblasts in biopsy specimens obtained from patients with OCP. TGF-beta1 induced the expression of HSP47 and type I collagen by conjunctival fibroblasts. Increased levels of TGF-beta1 and HSP47 may regulate increased synthesis, assembly, and production of collagens and thereby could significantly contribute to the process of conjunctival scarring in patients with OCP.
由于胶原蛋白过度积累导致的黏膜下纤维化是眼部瘢痕性类天疱疮（OCP）发病机制中的一个重要组织学特征。热休克蛋白47（HSP47）是一种胶原蛋白结合蛋白，在原胶原蛋白的生物合成中起重要作用。在本研究中，我们探讨了HSP47在OCP患者结膜瘢痕形成中的作用。
研究了15例OCP患者和5例正常受试者结膜的活检标本中HSP47、转化生长因子（TGF）-β1、I型胶原蛋白和III型胶原蛋白的表达。通过免疫染色、蛋白质印迹分析和定量实时PCR研究了TGF-β1对结膜成纤维细胞诱导HSP47和I型胶原蛋白表达的作用。
与对照组相比，通过免疫组织化学检测发现OCP患者纤维化结膜中I型和III型胶原蛋白的积累增加。在对照结膜组织的上皮细胞和基质成纤维细胞中检测到HSP47的表达较弱且稀疏。与对照组相比，通过免疫组织化学检测发现，从OCP患者获得的结膜组织中的基质成纤维细胞中HSP47的表达明显增加。通过定量实时PCR，与对照结膜组织相比，在从OCP患者获得的结膜组织中发现HSP47的表达增加了3.4倍。与结膜组织相似，与对照成纤维细胞相比，从OCP患者结膜分离的成纤维细胞中HSP47的表达增加了4.8倍。当用不同浓度的TGF-β1处理结膜成纤维细胞时，检测到HSP47和I型胶原蛋白的表达上调。
本研究表明，从OCP患者获得的活检标本中结膜成纤维细胞中HSP47和TGF-β1的表达增加。TGF-β1诱导结膜成纤维细胞表达HSP47和I型胶原蛋白。TGF-β1和HSP47水平的增加可能调节胶原蛋白合成、组装和产生的增加，从而可能显著促进OCP患者的结膜瘢痕形成过程。
