Integrin α5β1 Protect from AKI-to-CKD Transition Through Inhibiting Tubular Epithelial Cell Autophagy

Background: The mechanism of AKI transit to CKD is unclear. We hypothesized integrin α5β1 were involved in the process through autophagy and regulated by microRNA(miR)-19-3p. Methods: Cisplatin (9mg/kg) was intraperitoneally injected to male C57BL/6J mice once a week for 4 times and terminated at day 24 to bild AKI-CKD model. Integrin α5β1 plasmid or inhibitor (ATN-161) was administrated to the model mice, and tested the level of Scr, BUN, LC3, Atg5 and PI3K-Akt-mTOR signaling pathway. In vitro, the HK-2 cell was stimulated with integrin α5β1 plasmid or ATN-161, and the expression of FN, a-SMA, LC-3β and Atg5 were examined. Inhibitor or mimic of miR-19-3p was given to normal mice or model mice, to explore the effect of miR-19-3p and the relationship with integrin α5β1. In vitro, the HK-2 cell was stimulated with mimic or inhibitor of miR-19-3p. Ultimately, the model mice were given 3-methyladenine (3-MA) (20mg/kg, i.p.) for 7 consective days from day 17 to day 23 to explore the role of autophagy. Results: In low-dose multiple cisplatin treated mice, the Scr and BUN were elevated significantly, the protein expression of FN and a-SMA were significantly increased, and as the same as fibrosis degree in kidney tissue. In model mice, integrin α5β1 was decreased in kidney tissue, but miR-19-3p was elevated. Transfecting plasmid to overexpress integrin α5β1 in model mice, the elevated Scr, BUN and FN and a-SMA decreased. Atg5 and LC-3β were decreased. The pPI3K/PI3K, pAKT/AKT, and p-mTOR/mTOR was suppressed in cisplatin stimulation, and was improved after overexpress integrin α5β1. When normal mice were administrated with ATN-161 to inhibit integrin α5β1 expression, the Scr level and a-SMA expression was increased. Pretreated with inhibitor of miR-19-3p in cisplatin induced mice, led to recovery of kidney function and kidney damage. The elevated protein expression of Atg5 was also decreased. However, miR-19-3p mimics lowered integrin α5β1 expression significantly in HK-2 cells in vitro, and the inhibitor increased integrin α5β1 expression. At last, 3-MA treated with cisplatin suppressed autophagy and restore Scr, BUN, FN and a-SMA expression, but not integrin α5β1. Conclusion: Integrin α5β1 protect from cisplatin induced AKI to CKD transition by inhibiting autophagy, which through PI3K-Akt-mTOR signaling pathway, and negative regulated by miR-19-3p. Funding: Government Support – Non-U.S.