title: Hydrogen sulfide suppresses endoplasmic reticulum stress-induced endothelial-to-mesenchymal transition through Src pathway.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: 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.
authors.forename: Ru
authors.initials: R
authors.lastname: Ying
authors.affiliation: Department of Anesthesia, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, People's Republic of China.
authors.forename: Xiao-Qiao
authors.initials: XQ
authors.lastname: Wang
authors.affiliation: 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.
authors.forename: Ying
authors.initials: Y
authors.lastname: Yang
authors.affiliation: 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.
authors.forename: Zhen-Jie
authors.initials: ZJ
authors.lastname: Gu
authors.affiliation: 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.
authors.forename: Jing-Ting
authors.initials: JT
authors.lastname: Mai
authors.affiliation: 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.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Qiu
authors.affiliation: 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. Electronic address: tjcyx1995@163.com.
authors.forename: Yang-Xin
authors.initials: YX
authors.lastname: Chen
authors.affiliation: 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. Electronic address: dr_wjf@hotmail.com.
authors.forename: Jing-Feng
authors.initials: JF
authors.lastname: Wang
mesh_terms: D015536:Down-Regulation / Q000187:drug effects; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects*; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects*; D005355:Fibrosis; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D006862:Hydrogen Sulfide / Q000494:pharmacology*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D051899:Smad2 Protein / Q000037:antagonists & inhibitors / Q000502:physiology; D056811:Unfolded Protein Response / Q000187:drug effects; D019061:src-Family Kinases / Q000187:drug effects* / Q000502:physiology*
chemical_list: D019408:Platelet Endothelial Cell Adhesion Molecule-1; D034741:RNA, Small Interfering; C497782:SMAD2 protein, human; D051899:Smad2 Protein; D019061:src-Family Kinases; D006862:Hydrogen Sulfide
keywords: Endoplasmic reticulum stress; Endothelial-to-mesenchymal transition; Epithelial-to-mesenchymal transition; Human umbilical vein endothelial cells; Hydrogen sulfide; Unfolded protein response