MiR-221 negatively regulates innate anti-viral response

The innate immune system plays a critical role in the initial antiviral response. However, the timing and duration of these responses must be tightly regulated during infection to ensure appropriate immune cell activation and anti-viral defenses. Here we demonstrate that during antiviral response, a negative regulator miR-221 was also induced in an ELF4-dependent manner. We further show that ELF4 promotes miR-221 expression through direct binding to its promoter. Overexpression and knockdown assay show that miR-221 can negatively regulate IFNβ production in time of virus infection. RNA-seq analysis of miR-221 overexpressed cells revealed multiple candidate targets. Taken together, our study identified a novel negative microRNA regulator of innate antiviral response, which is dependent on ELF4.