MicroRNA 26a modulates regulatory T cells expansion and attenuates renal ischemia–reperfusion injury

• Mir-26a attenuates renal ischemia–reperfusion injury (IRI).
• Mir-26a modulates regulatory T cells (tregs) expansion in vivo and in vitro.
• Mir-26a promotes tregs expansion through repression of IL-6 expression.
• Mir-26a improves renal recovery in IRI.

Ischemia–reperfusion injury (IRI) was one of the main causes of acute kidney injury. Mir-26a has been reported to play functions in cellular differentiation, cell growth, cell apoptosis and metastasis. Furthermore, the renal vein levels of Mir-26a were demonstrated to be lower in the poststenotic kidney. However, the effect of Mir-26a on the renal IRI has never been investigated. In our current study, Mir-26a overexpression results in attenuated renal IRI and promoted tregs expansion. The promoted renal function after IRI induced by Mir-26a overexpression was abrogated by depletion of tregs with anti-CD25 antibodies. Mir-26a also significantly suppressed IL-6 expression. And IL-6 overexpression led to significant suppression of the Mir-26a-induced upregulation of Foxp3. Next, we performed additional experiments to determine the therapeutic potential of Mir-26a during the recovery phase after renal IRI. Results showed that Mir-26a treatment after IRI also induced significant expansion of Foxp3+CD4+ Tregs in both spleen and renal on day 10 after IRI. Taken together, our data indicate an important role for Mir-26a in promoting tregs expansion in renal IRI that involving repression of IL-6 expression.