MicroRNA 26a inhibits HMGB1 expression and attenuates cardiac ischemia-reperfusion injury

Ischemia reperfusion (IR) injury is a major issue in cardiac transplantation and inflammatory processes play a major role in myocardial IR injury. MicroRNA 26a (Mir-26a) plays important roles in cellular differentiation, cell growth, cell apoptosis and metastasis. Mir-26a has been demonstrated to modulate regulatory T cells expansion and attenuates renal IR injury. However, the role of Mir-26a in the cardiac IR injury has never been investigated. In our study, hearts of C57BL/6 mice were flushed and stored in cold Bretschneider solution for 8 hours and then transplanted into syngeneic recipients. The results demonstrate a crucial role for Mir-26a in inhibiting high mobility group box-1 (HMGB1) expression and attenuating cardiac IR injury. Mir-26a overexpression results in attenuated cardiac IR injury and inhibited HMGB1 expression. Mir-26a also inhibits inflammatory cells infiltration and cytokines expression. Furthermore, the attenuated cardiac IR injury induced by Mir-26a was abrogated by additional administration of recombinant HMGB1 (rHMGB1). In conclusion, Mir-26a plays a protective role in cardiomyocyte IR injury and this is associated with inhibited HMGB1 expression. (C) 2015 The Authors. Production and hosting by Elsevier B. V. on behalf of Japanese Pharmacological Society. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).