Ongoing chronic fibrosis and hypertrophy of the ligamentum flavum (LF) is an important cause of lumbar spinal canal stenosis (LSCS). Our previous work showed that WNT1-inducible signaling pathway protein 1 (WISP-1) is a critical driver of LF fibrosis. However, the potential mechanism has not been explored. Here, we found that Gli1 was upregulated in hypertrophic LF tissues and required for fibrogenesis in fibroblasts. Moreover, mechanical stretching increased the expression of WISP-1 in LF fibroblasts. Furthermore, WISP-1 induced fibrogenesis in vitro through the Hedgehog-Gli1 pathway. This conclusion was supported by the fact that WISP-1 activated the Hedgehog-Gli1 pathway in LF fibroblasts and that cyclopamine attenuated the effect of WISP-1-induced fibrogenesis. WISP-1 also promoted the transition of fibroblasts into myofibroblasts via the Hedgehog pathway. Importantly, a hypertrophic LF rabbit model induced by mechanical stress also showed pathological changes in fibrosis and elevated expression of WISP-1, Gli1, and α-SMA. Therapeutic administration of cyclopamine reduced collagen expression, fibroblast proliferation, and myofibroblast differentiation and ameliorated fibrosis in the mechanical stress-induced rabbit model. Collectively, our findings show mechanical stress/WISP-1/Hedgehog signaling as a new fibrotic axis contributing to LF hypertrophy and identify Hedgehog signaling as a therapeutic target for the prevention and treatment of LF fibrosis.

黄韧带 (LF) 的持续慢性纤维化和肥大是腰椎管狭窄症 (LSCS) 的重要原因。我们之前的工作表明，WNT1 诱导信号通路蛋白 1 (WISP-1) 是 LF 纤维化的关键驱动因素。然而，尚未探索潜在的机制。在这里，我们发现 Gli1 在肥大的 LF 组织中被上调，并且是成纤维细胞中纤维发生所必需的。此外，机械拉伸增加了 WISP-1 在 LF 成纤维细胞中的表达。此外，WISP-1 通过 Hedgehog-Gli1 通路在体外诱导纤维化。这一结论得到以下事实的支持：WISP-1 激活 LF 成纤维细胞中的 Hedgehog-Gli1 通路，并且环巴胺减弱 WISP-1 诱导的纤维发生的作用。WISP-1 还通过 Hedgehog 通路促进成纤维细胞向肌成纤维细胞的转变。重要的是，由机械应力诱导的肥大 LF 兔模型也显示出纤维化的病理变化和 WISP-1、Gli1 和 α-SMA 的表达升高。在机械应力诱导的兔模型中，环巴胺的治疗性给药减少了胶原蛋白表达、成纤维细胞增殖和肌成纤维细胞分化，并改善了纤维化。总的来说，我们的研究结果表明机械应力/WISP-1/Hedgehog 信号是导致 LF 肥大的新纤维化轴，并将 Hedgehog 信号确定为预防和治疗 LF 纤维化的治疗靶点。机械应力诱导的肥大 LF 兔模型也显示出纤维化的病理变化和 WISP-1、Gli1 和 α-SMA 的表达升高。在机械应力诱导的兔模型中，环巴胺的治疗性给药减少了胶原蛋白表达、成纤维细胞增殖和肌成纤维细胞分化，并改善了纤维化。总的来说，我们的研究结果表明机械应力/WISP-1/Hedgehog 信号是导致 LF 肥大的新纤维化轴，并将 Hedgehog 信号确定为预防和治疗 LF 纤维化的治疗靶点。机械应力诱导的肥大 LF 兔模型也显示出纤维化的病理变化和 WISP-1、Gli1 和 α-SMA 的表达升高。在机械应力诱导的兔模型中，环巴胺的治疗性给药减少了胶原蛋白表达、成纤维细胞增殖和肌成纤维细胞分化，并改善了纤维化。总的来说，我们的研究结果表明机械应力/WISP-1/Hedgehog 信号是导致 LF 肥大的新纤维化轴，并将 Hedgehog 信号确定为预防和治疗 LF 纤维化的治疗靶点。