MiR-223-5p And-3p Cooperatively Suppress Necroptosis In Ischemic/Reperfused Hearts

Objective:It has been clear that myocardial ischemia/reperfusion(I/R)-induced necrosis can be controlled by multiple genes.We recently observed that both miR-223-5p and-3p were expressed and functional in septic mouse hearts;and miR-223-3p was greatly up-regulated in I/R hearts.However,whether miR-223-3p/-5p duplex regulate I/R-triggered myocardial necroptosis remains unknown.METHODS AND RESULTS:In this study,we observed that miR-223-5p and-3p expression were differently altered in mouse hearts upon I/R.Pre-miR-223 transgenic(TG)and knockout(KO)mouse models were utilized and underwent global no-flow I/R.TG hearts exhibited significantly smaller infarction size and improved recovery of contractile performance over reperfusion period,which was accompanied with remarkable decreases in lactate dehydrogenase release and the extent of necrosis in TGs,compared to WTs.Conversely,pre-miR-223-KO hearts displayed opposite effects.In addition,TG hearts displayed inhibition of the RIP1-RIP3-MLKL necroptotic pathway and inflammatory response,whereas they were activated in pre-miR-223 KO hearts upon I/R.Accordingly,treatment of KO mice with necroptosis inhibitor,Nec-1s,significantly reduced I/R-triggered cardiac necroptosis,infarction size and dysfunction.Mechanistically,we identified two critical death receptors known to participate in the RIP1-dependent necrotic pathway,TNFR1 and DR6,as direct targets of miR-223-5p;meanwhile,miR-223-3p directly suppressed the expression of NLRP3 and IKK?,two important mediators known to beinvolved in I/R-induced inflammation and cell death.CONCLUSIONS:Our findings suggest that miR-223-5p/-3p duplex cooperatively inhibits I/R-induced necroptosis at multiple layers,leading to cardio-protection against I/R.Thus,pre-miR-223 may constitute a new therapeutic agent for the treatment of ischemic heart disease.