Ocular Wound Healing and Therapeutics, Singapore Eye Research Institute, Singapore.
J Cell Mol Med. 2012 Jun;16(6):1245-59. doi: 10.1111/j.1582-4934.2011.01400.x.
Failure of glaucoma filtration surgery (GFS) is commonly attributed to scarring at the surgical site. The human Tenon's fibroblasts (HTFs) are considered the major cell type contributing to the fibrotic response. We previously showed that SPARC (secreted protein, acidic, rich in cysteine) knockout mice had improved surgical success in a murine model of GFS. To understand the mechanisms of SPARC deficiency in delaying subconjunctival fibrosis, we used the gene silencing approach to reduce SPARC expression in HTFs and examined parameters important for wound repair and fibrosis. Mitomycin C-treated HTFs were used for comparison. We demonstrate that SPARC-silenced HTFs showed normal proliferation and negligible cellular necrosis but were impaired in motility and collagen gel contraction. The expression of pro-fibrotic genes including collagen I, MMP-2, MMP-9, MMP-14, IL-8, MCP-1 and TGF-β(2) were also reduced. Importantly, TGF-β(2) failed to induce significant collagen I and fibronectin expressions in the SPARC-silenced HTFs. Together, these data demonstrate that SPARC knockdown in HTFs modulates fibroblast functions important for wound fibrosis and is therefore a promising strategy in the development of anti-scarring therapeutics.
青光眼滤过手术（GFS）失败通常归因于手术部位的瘢痕形成。人眼Tenon 氏成纤维细胞（HTFs）被认为是导致纤维化反应的主要细胞类型。我们之前的研究表明，在 GFS 的小鼠模型中，缺失 SPARC（富含半胱氨酸的酸性分泌蛋白）的小鼠手术成功率更高。为了了解 SPARC 缺乏延迟结膜下纤维化的机制，我们使用基因沉默方法降低 HTFs 中的 SPARC 表达，并研究了对伤口修复和纤维化很重要的参数。用丝裂霉素 C 处理 HTFs 进行比较。我们证明，沉默 SPARC 的 HTFs 表现出正常的增殖和可忽略不计的细胞坏死，但运动性和胶原凝胶收缩受损。包括胶原 I、MMP-2、MMP-9、MMP-14、IL-8、MCP-1 和 TGF-β（2）在内的促纤维化基因的表达也降低。重要的是，TGF-β（2）未能诱导沉默 SPARC 的 HTFs 中显著的胶原 I 和纤维连接蛋白表达。总之，这些数据表明，HTFs 中的 SPARC 敲低调节了对伤口纤维化很重要的成纤维细胞功能，因此是开发抗瘢痕治疗的有前途的策略。
