Harnessing ZIKV NS2A RNA for alleviating acute hepatitis and cytokine release storm by targeting translation machinery

Background and Aims: Hyperactivated inflammatory responses induced by cytokine release syndrome (CRS) are the primary causes of tissue damage and even death. The translation process is precisely regulated to control the production of proinflammatory cytokines. However, it is largely unknown whether targeting translation can effectively limit the hyperactivated inflammatory responses during acute hepatitis and graft-versus-host disease (GVHD). Approach and Results: By using in vitro translation and cellular overexpression systems, we have found that the non-structural protein gene NS2A of Zika virus (ZIKV) functions as RNA molecules to suppress the translation of both ectopic genes and endogenous proinflammatory cytokines. Mechanistically, results from RNA pulldown and co-immunoprecipitation (Co-IP) assays have demonstrated that NS2A RNA interacts with the translation initiation factor eIF2α to disrupt the dynamic balance of the eIF2/eIF2B complex and translation initiation, which is the rate-limiting step during the translation process. In the acetaminophen (APAP)-, LPS/D-galactosamine (D-GalN)-, viral infection-induced acute hepatitis, and GVHD mouse models, mice with myeloid cell-specific knock-in of NS2A show decreased levels of serum proinflammatory cytokines and reduced tissue damage. Conclusions: ZIKV NS2A dampens the production of proinflammatory cytokines and alleviates inflammatory injuries by interfering translation process as RNA molecules, which suggests that NS2A RNA is potentially used to treat numerous acute inflammatory diseases characterized by CRS.