Host relieves lnc-IRAK3-3-sequestered miR-891b to attenuate apoptosis in Enterovirus 71 infection

Enterovirus 71 (EV71) is an emerging life-threatening pathogen particularly in the Asia-Pacific region. Apoptosis is a major pathogenic feature in EV71 infection. However, which molecular mechanism participating in EV71-induced apoptosis is not completely understood. Long noncoding RNAs (lncRNAs), a newly discovered class of regulatory RNA molecules, govern a wide range of biological functions through multiple regulatory mechanisms. Whether lncRNAs involved in EV71-induced apoptosis was investigated in this study. We conducted an apoptosis-oriented approach by integrating lncRNA and mRNA profilings. lnc-IRAK3-3 is down-regulated in EV71 infection and plays an important role in EV71 infection-induced apoptosis. Compensation of lnc-IRAK3-3 in EV71 infection promoted cell apoptosis wherein GADD45β expression was increased and further triggered caspase3 and PARP cleavage. Using bioinformatics analysis and functional assays, lnc-IRAK3-3 could functionally sequester miR-891b and GADD45β 3'UTR whereas miR-891b showed the inhibitory activity on GADD45β expression. Taken together, lnc-IRAK3-3 has the ability capturing miR-891b to enforce GADD45β expression and eventually promotes apoptosis. On the contrary, host cells suppress lnc-IRAK3-3 to relieve lnc-IRAK3-3-sequestered miR-891b, restrain GADD45β, and attenuate apoptosis in EV71 infection that prevent host cells from severe damages. We discover a new molecular mechanism by which host cells counteract EV71-induced apoptosis through the lnc-IRAK3-3/miR-891b/GADD45β axis partially.