Skin Bank Unit, Singapore General Hospital, Singapore.
J Dermatol Sci. 2011 Dec;64(3):199-209. doi: 10.1016/j.jdermsci.2011.09.008. Epub 2011 Sep 29.
Current evidence suggests the potential role of Wnt signalling in keloids pathogenesis but such literature remains scanty. We hypothesize that Wnt signalling is upregulated in keloid fibroblasts (KFs) and this promotes cellular growth, migration and extracellular matrix (ECM) production in such fibroblasts.
To verify the downregulation of secreted frizzled-related protein 1 (SFRP1), a Wnt inhibitor and test KFs sensitivity to Wnt3a treatment compared to NFs in terms of activation of Wnt/β-catenin, cellular growth, migration and ECM expressions. Next, to investigate if ectopic expression of SFRP1 and treatment of quercetin in KFs can reverse their phenotypes.
Quantitative Real-time PCR and western blotting were used to verify SFRP1 expression in NFs and KFs. The fibroblasts were tested with Wnt3a conditioned media and its effects were tested for (1) the cells' sensitivity to direct Wnt signalling via the activation of TCF reporter assay and protein expression of β-catenin, (2) cellular growth, (3) cell migration and (4) expressions of ECM components. Finally KFs were stably transduced with SFRP1 and treated with 2 doses of quercetin.
Lower levels of SFRP1 were confirmed at mRNA and protein levels in KFs which partly explained their sensitivity to Wnt3a treatment in terms of higher Wnt activation, cellular growth and fibronectin expression. Interestingly, Wnt3a did not promote higher cell migration rate and increase in collagen I expression. Ectopic expression of SFRP1 and quercetin treatment was able to mitigate Wnt3a-mediated phenotype of KFs.
Using SFRP1 or inhibitors of Wnt signalling might be one of the therapeutic solutions to treat keloid scarring.
目前的证据表明 Wnt 信号在瘢痕疙瘩发病机制中具有潜在作用，但此类文献仍然很少。我们假设 Wnt 信号在瘢痕疙瘩成纤维细胞（KFs）中上调，这促进了这些成纤维细胞的细胞生长、迁移和细胞外基质（ECM）产生。
验证 Wnt 抑制剂分泌型卷曲相关蛋白 1（SFRP1）的下调，并测试 KFs 与 NF 相比，在 Wnt/β-连环蛋白激活、细胞生长、迁移和 ECM 表达方面对 Wnt3a 处理的敏感性。接下来，研究在 KFs 中外源性表达 SFRP1 和用槲皮素处理是否可以逆转其表型。
使用定量实时 PCR 和 Western 印迹验证 NF 和 KFs 中的 SFRP1 表达。用 Wnt3a 条件培养基测试成纤维细胞，并测试其作用（1）通过 TCF 报告基因测定和β-连环蛋白蛋白表达直接检测细胞对 Wnt 信号的敏感性，（2）细胞生长，（3）细胞迁移和（4）ECM 成分的表达。最后，用 SFRP1 稳定转导 KFs 并分别用 2 剂量槲皮素处理。
在 KFs 中 SFRP1 的水平在 mRNA 和蛋白水平均较低，这部分解释了它们对 Wnt3a 治疗的敏感性，表现为更高的 Wnt 激活、细胞生长和纤维连接蛋白表达。有趣的是，Wnt3a 并没有促进更高的细胞迁移率和胶原蛋白 I 表达增加。外源性表达 SFRP1 和槲皮素处理能够减轻 Wnt3a 介导的 KFs 表型。
使用 SFRP1 或 Wnt 信号抑制剂可能是治疗瘢痕疙瘩的一种治疗方法。
