Effect Of Erythropoietin On Albumin Induced Transition In Human Kidney Proximal Tubular Epithelial Cells And The Relationship Between TGFβ1/ILK Signaling Pathway

Objective: To investigate the effect of erythropoietin(EPO) on albumin inducedepithelial-mesenchymal transition(EMT) in human renal proximal tubular epithelialcells(HK-2) and the relationship between TGFβ1/ILK signaling pathway. To searchthe possible mechanisms of EPO attenuate the extent of renal fibrosis.Methods: HK-2cells which cultured in vitro were divided into several groupsrandomly:①blank control group:untreated HK-2cells.②EPO induced group:HK-2cells were treated with20U/ml EPO.③albumin induced group: HK-2cells weretreated with5mg/ml albumin.④EPO inhibited group: HK-2cells were treated withdifferent concentrations of EPO(5,10,20U/ml) and5mg/ml albumin.⑤inhibitor ofTGFβ1receptor group: SB431542and5mg/ml albumin.24hours later, reversetranscription polymerase chain reaction(RT-PCR) was used to evaluate the mRNAlevels of TGFβ1and ILK.THE levels of E-cadherin and α-smooth muscleactin(α-SMA) proteins were assessed by immunofluorescent. ELISA was used tomeasured the levels of FN proteins in supernatant.Results:①Compared withblank control group and EPO induced group, theexpression of TGFβ1, ILK mRNA was significantly increased in the albumininduced group(P<0.05). EPO inhibited group TGFβ1, ILK mRNA expressionssignificantly decreased (P<0.05). The higher concentration of EPO, the biggerinhibitory effect on TGFβ1, ILK mRNA expression. ILK mRNA was alsosignificantly decreased in the inhibitor of TGFβ1receptor group.②Immunofluorescent showed that the expression of E-cadherin proteins decreasedand the expression of α-SMA proteins increased in the albumin inducedgroup(P<0.05). Meanwhile, the expression of E-cadherin proteins significantlyincreased and the expression of α-SMA proteins significantly decreased in the EPOinhibited group and inhibitor of TGFβ1receptor group as compared to the albumininduced group(P<0.05), and the effects were related to the concentration of EPO.③ELISA method showed the expression of FN proteins significantly decreased in the EPO inhibited group and inhibitor of TGFβ1receptor group when comparing with thealbumin induced group(P<0.05).④There was positive correlation between theexpression of TGFβ1mRNA and ILK mRNA in the albumin induced group and EPOinhibited group by pearson correlation analysis (r=0.9,0.895,0.825,0.948, P<0.05).Conclusions: Albumin can induce the expression of E-cadherin proteins high and theexpression of α-SMA and FN proteins low in cultured HK-2cells by increasing theexpression of TGFβ1, ILK mRNA.The process can induce HK-2cells EMT, andExtracellular matrix(ECM) production.EPO can inhibit albumin induced EMT indose-dependent manner, finally attenuate renal fibrosis. The mechansim may berelated to its inhibition of TGFβ1/ILK signaling pathway.