Transforming growth factor β (TGFβ) signaling plays crucial roles in maintaining vascular integrity and homeostasis, and is established as a strong activator of vascular smooth muscle cell (VSMC) differentiation. Chronic inflammation is a hallmark of various vascular diseases. Although TGFβ signaling has been suggested to be protective against inflammatory aortic aneurysm progression, its exact effects on VSMC inflammatory process and the underlying mechanisms are not fully unraveled. Here we revealed that TGFβ1 suppressed the expression of a broad array of proinflammatory genes while potently induced the expression of contractile genes in cultured primary human coronary artery SMCs (HCASMCs). The regulation of TGFβ1 on VSMC contractile and proinflammatory gene programs appeared to occur in parallel and both processes were through a SMAD4-dependent canonical pathway. We also showed evidence that the suppression of TGFβ1 on VSMC proinflammatory genes was mediated, at least partially through the blockade of signal transducer and activator of transcription 3 (STAT3) and NF-κB pathways. Interestingly, our RNA-seq data also revealed that TGFβ1 suppressed gene expression of a battery of autophagy mediators, which was validated by western blot for the conversion of microtubule-associated protein light chain 3 (LC3) and by immunofluo-rescence staining for LC3 puncta. However, impairment of VSMC autophagy by ATG5 deletion failed to rescue TGFβ1 influence on both VSMC contractile and proinflammatory gene programs, suggesting that TGFβ1-regulated VSMC differentiation and inflammation are not attributed to TGFβ1 suppression on autophagy. In summary, our results demonstrated an important role of TGFβ signaling in suppressing proinflammatory gene program in cultured primary human VSMCs via the blockade on STAT3 and NF-κB pathway, therefore providing novel insights into the mechanisms underlying the protective role of TGFβ signaling in vascular diseases.

转化生长因子 β (TGFβ) 信号传导在维持血管完整性和体内平衡中起着至关重要的作用，并被确立为血管平滑肌细胞 (VSMC) 分化的强激活剂。慢性炎症是各种血管疾病的标志。尽管 TGFβ 信号转导被认为对炎症性主动脉瘤进展具有保护作用，但其对 VSMC 炎症过程的确切影响及其潜在机制尚未完全阐明。在这里，我们发现 TGFβ1 抑制了广泛的促炎基因的表达，同时有效地诱导了培养的原代人冠状动脉 SMC (HCASMC) 中收缩基因的表达。TGFβ1 对 VSMC 收缩和促炎基因程序的调节似乎是同时发生的，并且这两个过程都是通过 SMAD4 依赖的经典途径进行的。我们还表明，至少部分通过阻断信号转导和转录激活因子 3 (STAT3) 和 NF-κB 通路介导了 TGFβ1 对 VSMC 促炎基因的抑制。有趣的是，我们的 RNA-seq 数据还显示 TGFβ1 抑制了一系列自噬介质的基因表达，这通过蛋白质印迹验证了微管相关蛋白轻链 3 (LC3) 的转化和 LC3 斑点的免疫荧光染色. 然而，ATG5 缺失对 VSMC 自噬的损害未能挽救 TGFβ1 对 VSMC 收缩和促炎基因程序的影响，表明TGFβ1调节的VSMC分化和炎症不归因于TGFβ1对自噬的抑制。总之，我们的研究结果证明了 TGFβ 信号传导通过阻断 STAT3 和 NF-κB 通路在抑制培养的原代人 VSMC 中促炎基因程序中的重要作用，因此为 TGFβ 信号传导在血管疾病中的保护作用机制提供了新的见解。 .