Interferon stimulated gene 15 promotes Zika virus replication through regulating Jak/STAT and ISGylation pathways.

• Zika virus (ZIKV) is an emerging arbovirus alarming public health emergency in South America. • Zika virus infection is known to cause microcephaly in pregnant women, as well as other congenital defects and Guillain-Barré syndrome. • Unfortunately, no vaccines or specific antiviral therapies are available for the prevention or treatment of ZIKV infection. • Therefore, it is particularly important to understand the molecular pathogenesis of ZIKV in order to develop effective antiviral therapies and preventive vaccines. • IFN-stimulated gene 15 (ISG15) is an important host factor exploited by ZIKV to facilitate its replication through regulating Jak/STAT and ISGylation pathways, ISG15 might serve as a potential target for the development of novel antiviral agents. Zika virus is an emergent arbovirus that has caused a public health emergency in South America. Zika virus infection is known to cause microcephaly and other congenital defects and Guillain-Barré syndrome. Unfortunately no direct antiviral treatments are available at present. IFN-stimulated gene 15 (ISG15) is one of the most upregulated host genes following type I interferon treatment or virus infections. ISG15 has been shown to have antiviral effect on a wide variety of viruses although pro-HCV replication was observed. However, the effect of ISG15 on ZIKV infection is not well defined. In this study, we try to clarify the effect of ISG15 on ZIKV replication and to further dissect the underlying mechanism. Our results indicated that ZIKV infection led to the increased expression of ISG15 in A549, 2fTGH, U5A cells. Overexpression of ISG15 stimulated ZIKV replication although ISG15 did not affect the viral entry. Further studies showed that this proviral effect was mediated through Jak/STAT signaling pathway and was ISGylation-dependent. Taken together, our work demonstrates that ISG15 is an important host factor exploited by ZIKV to facilitate its replication and might serve as a potential target for the development of novel antiviral agents. [ABSTRACT FROM AUTHOR]