title: MicroRNA-7-5p regulates human alveolar epithelial sodium channels by targeting the mTORC2/SGK-1 signaling pathway.
abstract: The aim of this study was to investigate the effect of miRNA-7-5p on human alveolar epithelial sodium channels and clarify the pathway in which miRNA-7-5p regulates the expression of ENaC in ARDS.
  
  
  
  Dual luciferase target gene validation experiments were used to confirm whether mTOR and SGK-1 are the target genes of miRNA-7-5p. Then, we overexpressed and inhibited miRNA-7-5p in the human alveolar epithelial cell line A549, respectively. LPS at a concentration of 100 ng/mL was used to stimulate the cells. The expressions ofmiRNA-7-5p, mTOR, SGK-1, p-Akt-Ser473, α-, β-, and γ-ENaC were detected by quantitative RT polymerase chain reaction (qRT-PCR) and western blotting.
  
  
  
  In this study, we first confirmed that mTOR and SGK-1 are the target genes of miRNA-7-5p. Then, we found that mRNA expression levels of both mTOR and SGK-1 were downregulated to 0.54- and 0.3-fold, respectively, in the miRNA-7-5p mimic groups than the blank controls (P < 0.01). MiRNA-7-5p overexpression inhibited mTORC2/SGK-1 signaling pathway activity and reduced ENaC expression. The expression of miRNA-7-5p was significantly upregulated in A549 cells stimulated with lipopolysaccharide (LPS) and downregulated mRNA expression levels of both mTOR and SGK-1. After transfection with miRNA-7-5p inhibitors, we found that the mTORC2/SGK-1 pathway activity was restored compared to the group with LPS stimulation only, and the ENaC expression was also obviously increased.
  
  
  
  Our results demonstrate that miRNA-7-5p can regulate the expression of human alveolar ENaC by targeting the mTORC2/SGK-1 signaling pathway. The inhibition of miRNA-7-5p can enhance the expression of ENaC, which may provide a new target for the treatment of ARDS.
authors.affiliation: a Department of Respiratory Medicine , The Second Affiliated Hospital of Chongqing Medical University , Chongqing , China.
authors.forename: Ke
authors.initials: K
authors.lastname: Qin
authors.affiliation: a Department of Respiratory Medicine , The Second Affiliated Hospital of Chongqing Medical University , Chongqing , China.
authors.forename: Xi
authors.initials: X
authors.lastname: Zhong
authors.affiliation: a Department of Respiratory Medicine , The Second Affiliated Hospital of Chongqing Medical University , Chongqing , China.
authors.forename: Daoxin
authors.initials: D
authors.lastname: Wang
mesh_terms: D000072283:A549 Cells; D056809:Alveolar Epithelial Cells / Q000378:metabolism*; D053503:Epithelial Sodium Channels / Q000378:metabolism*; D006801:Humans; D017874:Immediate-Early Proteins / Q000378:metabolism*; D000076225:Mechanistic Target of Rapamycin Complex 2 / Q000378:metabolism*; D035683:MicroRNAs / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D015398:Signal Transduction; D000099184:Serum-Glucocorticoid Regulated Kinases
chemical_list: D053503:Epithelial Sodium Channels; D017874:Immediate-Early Proteins; D000076225:Mechanistic Target of Rapamycin Complex 2; D035683:MicroRNAs; D017346:Protein Serine-Threonine Kinases; D000099184:Serum-Glucocorticoid Regulated Kinases; C549242:MIRN7-1 microRNA, human
keywords: SGK-1; acute respiratory distress syndrome; epithelial sodium channel; mTOR; mTORC2/SGK-1; microRNA-7-5p