title: Effect of pro-inflammatory interleukin-17A on epithelial cell phenotype inversion in HK-2 cells in vitro.
abstract: Renal interstitial fibrosis (RIF) is a pathological change common to a variety of chronic renal diseases, ultimately progressing to end-stage renal failure. It is believed that epithelial cell phenotype inversion plays an important role in RIF, which is characterized by expression of the mesenchymal maker α-SMA, loss of the epithelial maker E-cadherin, and enhanced secretion of extracellular matrix. IL-17, a newly discovered pro-inflammatory cytokine, has recently been reported to play an important role in tissue fibrosis, involving pulmonary, liver, intestine and skin tissues. This study aimed to investigate whether IL-17A, a member of the IL-17 family, can induce epithelial cell phenotype inversion, and to explore the molecular mechanism of this phenotype inversion, in vitro. HK-2 cells were cultured and incubated with IL-17A. Cell proliferation was measured by CCK-8 assay, and the secretion of types I and III collagen was detected by ELISA in dose-dependent and time-dependent experiments. To find out whether IL-17A can induce epithelial cell phenotype inversion, HK-2 cells were stimulated with 80 ng/mL of IL-17A and 10 ng/mL of TGF-β1 as a positive control, for 72 h. To explore the potential signaling pathway, anti-TGF-β1 antibody was added before IL-17A treatment. At the same time, anti-TGF-β1 antibody alone was added to the medium as the negative control group. The expression of types I and III collagen, α-SMA and E-cadherin proteins, and mRNA was measured by real-time PCR, western blotting and immuno-histochemistry. IL-17A promoted the proliferation of HK-2 cells and secretion of types I and III collagen in a dose-dependent and time-dependent manner. Compared with the normal control, IL-17A could stimulate the expression of α-SMA, types I and III collagen, and suppressed the expression of E-cadherin in HK-2 cells. Incubation of IL-17A with TGF-β1 antibody decreased significantly the expression of α-SMA, but increased the expression of E-cadherin in HK-2 cells. Our results suggest that IL-17A might promote the proliferation of HK-2 cells and secretion of extracellular matrix, and induce epithelial cell phenotype inversion via a TGF-β1-dependent pathway. Blocking the pro-inflammatory cytokine IL-17A might be a potential target for the treatment of fibrotic kidney disease.
authors.affiliation: Department of Nephrology, Affiliated Hospital of Luzhou Medical College, Luzhou City 646000,Sichuan Province, China, People's Hospital of Jianyang, Ziyang City 641400, Sichuan Province, China.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Nephrology, Affiliated Hospital of Luzhou Medical College, Luzhou City 646000,Sichuan Province, China, People's Hospital of Jianyang, Ziyang City 641400, Sichuan Province, China.
authors.forename: Fu-Gang
authors.initials: FG
authors.lastname: Li
authors.affiliation: Department of Nephrology, Shanghai general hospital, Shanghai Jiao Tong University, Shanghai City 200080, China.
authors.forename: Man
authors.initials: M
authors.lastname: Yang
authors.affiliation: Department of Nephrology, Affiliated Hospital of Luzhou Medical College, Luzhou City 646000,Sichuan Province, China, Department of Nephrology, West China Hospital of Sichuan University, Chengdu City610041, Sichuan Province, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Nephrology, Affiliated Hospital of Luzhou Medical College, Luzhou City 646000,Sichuan Province, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Central Service, West China Hospital of Sichuan University, Chengdu City 610041, Sichuan Province, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Nephrology, West China Hospital of Sichuan University, Chengdu City610041, Sichuan Province, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Ji
authors.affiliation: Department of Nephrology, Affiliated Hospital of Luzhou Medical College, Luzhou City 646000,Sichuan Province, China, Department of Nephrology, West China Hospital of Sichuan University, Chengdu City610041, Sichuan Province, China, State Key Laboratory of Biotherapy of Human Disease, West China Hospital, Sichuan University, Chengdu City 610041, Sichuan Province, China., People's Hospital of Jianyang, Ziyang City 641400, Sichuan Province, China.
authors.forename: Jun-Ming
authors.initials: JM
authors.lastname: Fan
mesh_terms: D015415:Biomarkers; D049109:Cell Proliferation / Q000187:drug effects*; D024042:Collagen Type I / Q000378:metabolism; D024043:Collagen Type II / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism* / Q000494:pharmacology; D020381:Interleukin-17 / Q000378:metabolism* / Q000494:pharmacology; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000378:metabolism; D010641:Phenotype
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D024043:Collagen Type II; D018836:Inflammation Mediators; D020381:Interleukin-17