Background: Urethral stricture is a common disorder of the lower urinary tract in men. A complex network of pathways and interactions are involved in the pathogenesis of urethral fibrosis. However, the mechanisms underlying urethral fibrosis remain poorly understood. Objectives: To investigate the critical role of the canonical Wnt pathway in development of urethral fibrosis and explore DKK1, the endogenous inhibitor of Wnt pathway, as a potential target to prevent urethral fibrosis in vitro and in vivo. Methods: Urethral fibrosis tissue derived from patients and rat models were harvested to assess the activation of the canonical Wnt pathway by using western blot, qRT-PCR and immunohistochemistryWe performed histological staining, western blot, qRT-PCR and immunohistochemistry to examine the effects of DKK1 treatment on in vivo rat urethral fibrosis models. In vitro, human urethral fibroblasts (HUFs) were cultured to examine the effects of DKK1 in TGFβ1-induced HUFs by CCK-8 assay, hydroxyproline assay, flow cytometry, cell migration assay, western blot, qRT-PCR and immunofluorescence. Results: The key components of Wnt signaling were upregulated in urethral fibrosis tissue derived from patients and rat models while DKK 1 was downregulated. DKK1 ameliorated TGFβ1-induced urethral fibrosis in rats. TGFβ1 induced myofibroblast differentiation by upregulating collagen I, collagen III, α-SMA, β-catenin and p-GSK-3β, while DKK1 was decreased. DKK1 significantly inhibited cell proliferation, collagen content, cell migration and promoted cell apoptosis in TGFβ1-induced HUFs. DKK1 significantly suppressed myofibroblast differentiation of TGFβ1-induced HUFs by downregulating collagen I, collagen III, α-SMA, β-catenin and p-GSK-3β with a mechanism independent of Smad2/3. Conclusions: Our study demonstrated that canonical Wnt pathway may be an essential mechanism underlying the pathogenesis of urethral fibrosis and explored the potential role of DKK1 participation in the development of urethral fibrosis.

中文翻译：

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DKK1 通过调节经典 Wnt 通路改善体内和体外尿道纤维化中肌成纤维细胞的分化。

背景：尿道狭窄是男性下尿路的常见疾病。尿道纤维化的发病机制涉及复杂的途径和相互作用网络。然而，尿道纤维化的机制仍知之甚少。目的：探讨经典Wnt通路在尿道纤维化发生过程中的关键作用，并探索Wnt通路内源性抑制剂DKK1作为体外和体内预防尿道纤维化的潜在靶点。方法：收集患者和大鼠模型的尿道纤维化组织，通过蛋白质印迹、qRT-PCR 和免疫组织化学评估经典 Wnt 通路的激活情况，我们进行组织学染色、蛋白质印迹、qRT-PCR 和免疫组织化学来检查 DKK1 的作用对体内大鼠尿道纤维化模型的治疗。在体外培养人尿道成纤维细胞 (HUF)，通过 CCK-8 测定、羟脯氨酸测定、流式细胞术、细胞迁移测定、蛋白质印迹、qRT-PCR 和免疫荧光检查 DKK1 对 TGFβ1 诱导的 HUF 的影响。结果：在患者和大鼠模型的尿道纤维化组织中，Wnt 信号传导的关键成分上调，而 DKK 1 下调。DKK1 可改善 TGFβ1 诱导的大鼠尿道纤维化。TGFβ1 通过上调胶原蛋白 I、胶原蛋白 III、α-SMA、β-连环蛋白和 p-GSK-3β 诱导肌成纤维细胞分化，同时减少 DKK1。DKK1 显着抑制 TGFβ1 诱导的 HUF 中的细胞增殖、胶原含量、细胞迁移并促进细胞凋亡。DKK1 通过下调胶原蛋白 I、胶原蛋白 III、α-SMA、β-catenin 和 p-GSK-3β 显着抑制 TGFβ1 诱导的 HUF 的肌成纤维细胞分化，其机制独立于 Smad2/3。结论：我们的研究表明经典Wnt通路可能是尿道纤维化发病机制的重要机制，并探讨了DKK1参与尿道纤维化发生发展的潜在作用。