Department of Cardiology, the First Hospital of China Medical University, Shenyang, Liaoning, PR China.
Department of Cardiology, the First Hospital of China Medical University, Shenyang, Liaoning, PR China.
Life Sci. 2020 Sep 15;257:118053. doi: 10.1016/j.lfs.2020.118053. Epub 2020 Jul 4.
Vascular smooth muscle cells (VSMCs) play a crucial role in the progression of atherosclerosis. Paired box 9 (Pax9) is a member of the Pax gene family which participates in the development of various tissues and organs. However, the effect of Pax9 on atherosclerosis and VSMCs and the underlying mechanisms remain unclear.
Western blotting was performed to assess Pax9 expression in atherosclerosis and VSMCs. Pax9 siRNA and overexpression plasmid were constructed to explore the biological function. Cell proliferation assay, phalloidin staining, and Transwell assay, accompanied by the sonic hedgehog (Shh) signaling pathway antagonist, cyclopamine (5 μM) and agonist, SAG (100 nM), were used to evaluate the VSMC phenotype, proliferation, and migration, as well as explore the associated mechanisms.
We first discovered Pax9 to be significantly increased in atherosclerotic mice and platelet-derived growth factor-BB (PDGF-BB)-induced VSMCs. Pax9 knockdown inhibited the phenotypic transformation, proliferation, and migration of VSMCs, whereas the opposite effect was observed when Pax9 was overexpressed. Next, we established that Shh was activated in PDGF-BB-induced VSMCs. Moreover, Pax9 overexpression further activated Shh and exacerbated the phenotypic transformation, proliferation, and migration of PDGF-BB-induced VSMCs. These changes were effectively inhibited by treatment with the Shh signaling pathway antagonist. Consistently, Pax9 knockdown down-regulated Shh expression and inhibited the phenotypic transformation, proliferation, and migration of PDGF-BB-induced VSMCs. Treatment with the Shh signaling pathway agonist prevented these changes.
Pax9 regulated VSMC phenotypic transformation, proliferation, and migration via Shh, which may represent a novel target for the treatment of atherosclerosis.
血管平滑肌细胞（VSMCs）在动脉粥样硬化的进展中起着至关重要的作用。配对盒 9（Pax9）是 Pax 基因家族的一员，参与各种组织和器官的发育。然而，Pax9 对动脉粥样硬化和 VSMCs 的影响及其潜在机制尚不清楚。
采用 Western blot 法检测动脉粥样硬化和 VSMCs 中 Pax9 的表达。构建 Pax9 siRNA 和过表达质粒，探讨其生物学功能。采用细胞增殖实验、鬼笔环肽染色和 Transwell 实验，结合 sonic hedgehog（Shh）信号通路拮抗剂环巴胺（5μM）和激动剂 SAG（100nM），评估 VSMC 表型、增殖和迁移，并探讨相关机制。
我们首次发现 Pax9 在动脉粥样硬化小鼠和血小板衍生生长因子-BB（PDGF-BB）诱导的 VSMCs 中显著增加。Pax9 敲低抑制了 VSMCs 的表型转化、增殖和迁移，而 Pax9 过表达则观察到相反的效果。接下来，我们发现 PDGF-BB 诱导的 VSMCs 中 Shh 被激活。此外，Pax9 过表达进一步激活了 Shh，并加剧了 PDGF-BB 诱导的 VSMCs 的表型转化、增殖和迁移。这些变化通过使用 Shh 信号通路拮抗剂得到有效抑制。一致地，Pax9 敲低下调了 Shh 的表达，并抑制了 PDGF-BB 诱导的 VSMCs 的表型转化、增殖和迁移。Shh 信号通路激动剂的处理阻止了这些变化。
Pax9 通过 Shh 调节 VSMC 的表型转化、增殖和迁移，这可能代表了治疗动脉粥样硬化的一个新靶点。
