Department of Cardiology, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou 510120, People's Republic of China; Guangdong Province Key Laboratory of Arrhythmia and Electrophysiology, Guangzhou 510120, People's Republic of China.
Department of Anesthesia, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, People's Republic of China.
Life Sci. 2016 Jan 1;144:208-17. doi: 10.1016/j.lfs.2015.11.025. Epub 2015 Dec 2.
Hydrogen sulfide (H2S) ameliorates cardiac fibrosis in several models by suppressing endoplasmic reticulum (ER) stress. Endothelial-to-mesenchymal transition (EndMT) is implicated in the development of cardiac fibrosis. Therefore, we investigated whether H2S could attenuate EndMT by suppressing ER stress.
ER stress was induced by tunicamycin (TM) and thapsigargin (TG) and inhibited by 4-phenylbutyrate (4-PBA) in human umbilical vein endothelial cells (HUVECs). ER stress and EndMT were measured by Western blot, Real-Time PCR and immunofluorescence staining. Inhibition Smad2 and Src pathway were performed by specific inhibitors and siRNA. Ultrastructural examination was detected by transmission electron microscope. The functions of HUVECs were investigated by cell migration assay and tube formation in vitro.
Under ER stress, the expression of endothelial marker CD31 significantly decreased while mesenchymal markers α-SMA, vimentin and collagen 1 increased which could be inhibited by 4-PBA. Moreover, HUVECs changed into a fibroblast-like appearance with the activation of Smad2 and Src kinase pathway. After inhibiting Src pathway, EndMT would be significantly inhibited. TM reduced H2S levels in cell lysate and H2S pretreatment could preserve endothelial cell appearance with decreased ER stress and ameliorated dilation of ER. H2S could also downregulate the mesenchymal marker expression, and upregulate the endothelial markers expression, accompanied with the suppression of Src pathway. Moreover, H2S partially restored the capacity of migration and tube formation in HUVECs.
These results revealed that H2S could protect against ER stress-induced EndMT through Src pathway, which may be a novel role for the cardioprotection of H2S.
硫化氢（H2S）通过抑制内质网（ER）应激减轻几种模型中的心肌纤维化。内皮细胞向间充质转化（EndMT）与心肌纤维化的发展有关。因此，我们研究了 H2S 是否可以通过抑制 ER 应激来减轻 EndMT。
用衣霉素（TM）和他普西龙（TG）诱导 ER 应激，并用人脐静脉内皮细胞（HUVEC）中的 4-苯基丁酸（4-PBA）抑制 ER 应激。通过 Western blot、实时 PCR 和免疫荧光染色来测量 ER 应激和 EndMT。通过特异性抑制剂和 siRNA 抑制 Smad2 和 Src 通路。通过透射电子显微镜检测超微结构检查。通过细胞迁移实验和体外管形成来研究 HUVEC 的功能。
在 ER 应激下，内皮标志物 CD31 的表达显著降低，而间充质标志物 α-SMA、波形蛋白和胶原 1 的表达增加，这可以被 4-PBA 抑制。此外，HUVEC 转变为成纤维细胞样外观，Smad2 和 Src 激酶途径被激活。抑制 Src 通路后，EndMT 会显著抑制。TM 降低细胞裂解物中的 H2S 水平，H2S 预处理可维持内皮细胞形态，减少 ER 应激，改善 ER 扩张。H2S 还可以下调间充质标志物的表达，上调内皮标志物的表达，并抑制 Src 通路。此外，H2S 部分恢复了 HUVEC 迁移和管形成的能力。
这些结果表明，H2S 可以通过 Src 通路保护 ER 应激诱导的 EndMT，这可能是 H2S 心脏保护的新作用。
