Department of Respiratory and Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, People's Republic of China.
Department of Respiratory and Critical Care Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, People's Republic of China.
Sleep Breath. 2024 Mar;28(1):291-300. doi: 10.1007/s11325-023-02889-y. Epub 2023 Sep 12.
To investigate whether or not intermittent hypoxia (IH), the main characteristic of obstructive sleep apnea (OSA) may affect the myofibroblast differentiation and extracellular matrix (ECM) production of lung fibroblast through the HIF-1α-TGF-β/Smad pathway and assess the interventional role of a HIF-1α inhibitor, 2-methoxyestradiol (2-ME2).
The human lung fibroblast MRC5 cells were exposed to normoxia or IH conditions, and the expression of myofibroblast differentiation marker α-smooth muscle actin (α-SMA) and ECM protein collagen I were evaluated. To clarify the underlying mechanism, the expression level of HIF-1α, TGF-β, and p-Smads/Smads were measured and the effects of inhibiting HIF-1α with 2-ME2 on the α-SMA expression level and ECM production through the TGF-β/Smad pathway were assessed. Si HIF-1α was applied to genetically inhibit HIF-1α in MRC5 cells, and the related proteins were assessed.
IH increased the protein and mRNA expression of Collagen I and α-SMA of MRC5 cells in a time-dependent manner. IH activated the protein and mRNA level of HIF-1α and TGF-β and increased the phosphorylation of Smad2/Smad3 of MRC5 cells in a time-dependent manner. 2-ME2 inhibited the activation of HIF-1α induced by IH and decreased overexpression of TGF-β, p-Smad2/Smad2, and p-Smad3/Smad3, which in turn partially reversed the upregulation of α-SMA and Collagen I induced by IH in MRC5 cells. When HIF-1α was successfully silenced by si-HIF-1α, upregulation of TGF-β induced by intermittent hypoxia was partially decreased.
This study showed that IH contributes to myofibroblast differentiation and excessive ECM production of MRC5 cells through activation of the HIF-1α-TGF-β/Smad pathway. 2-ME2 partially attenuated myofibroblast differentiation induced by IH by inhibiting the HIF-1α-TGF-β/Smad pathway.
通过 HIF-1α-TGF-β/Smad 通路研究间歇性低氧（IH）作为阻塞性睡眠呼吸暂停（OSA）的主要特征，是否会影响肺成纤维细胞的肌成纤维细胞分化和细胞外基质（ECM）产生，并评估 HIF-1α 抑制剂 2-甲氧基雌二醇（2-ME2）的干预作用。
将人肺成纤维细胞 MRC5 细胞暴露于常氧或 IH 条件下，评估肌成纤维细胞分化标志物α-平滑肌肌动蛋白（α-SMA）和 ECM 蛋白胶原 I 的表达。为了阐明潜在机制，测量 HIF-1α、TGF-β 和 p-Smad/Smad 的表达水平，并评估用 2-ME2 抑制 HIF-1α 对 TGF-β/Smad 通路中α-SMA 表达水平和 ECM 产生的影响。应用 SiHIF-1α 基因抑制 MRC5 细胞中的 HIF-1α，评估相关蛋白。
IH 呈时间依赖性增加 MRC5 细胞 Collagen I 和α-SMA 的蛋白和 mRNA 表达。IH 激活 HIF-1α 和 TGF-β 的蛋白和 mRNA 水平，并增加 MRC5 细胞 Smad2/Smad3 的磷酸化呈时间依赖性。2-ME2 抑制 IH 诱导的 HIF-1α 激活，并降低 TGF-β、p-Smad2/Smad2 和 p-Smad3/Smad3 的过表达，这反过来部分逆转了 IH 诱导的 MRC5 细胞中α-SMA 和 Collagen I 的上调。当 HIF-1α 被 si-HIF-1α 成功沉默时，间歇性低氧诱导的 TGF-β 上调部分减少。
本研究表明，IH 通过激活 HIF-1α-TGF-β/Smad 通路，促进 MRC5 细胞的肌成纤维细胞分化和 ECM 过度产生。2-ME2 通过抑制 HIF-1α-TGF-β/Smad 通路，部分减轻 IH 诱导的肌成纤维细胞分化。
