Coronavirus infections can trigger multiple modes of cell death, leading to severe infectious diseases. The process is modulated by host factors with mechanisms yet to be fully elucidated. Here, we first demonstrated that the host factor A20 regulated PANoptosis during porcine deltacoronavirus (PDCoV) infection, thereby contributing to the antiviral defense response. We found that PDCoV could induce PANoptosis in intestinal epithelial cells, which facilitates the extracellular release of viral particles through this form of programmed cell death. A20 restricted the PANoptosome assembly and downstream death signaling by targeting RIPK3 ubiquitin chains for degradation. Consequently, loss of A20 exacerbated cell lysis and enhanced the release of viral particles, although this effect does not alter viral entry or replication. We further established that PDCoV-induced PANoptosis-dependent release was driven by osmotic imbalance resulting from membrane pore formation mediated by GSDMD and MLKL, rather than by direct transmembrane egress of viral particles. Transwell models showed that pharmacological inhibition of the pore-forming activities of GSDMD and MLKL reduced viral dissemination and preserved epithelial barrier integrity. These findings advance our understanding of enteric coronavirus pathogenesis and suggest that the A20-PANoptosis axis represents a potential target for antiviral intervention.IMPORTANCECoronaviruses have repeatedly posed significant threats to both human and animal health. Here, we used porcine deltacoronavirus (PDCoV), a highly enterotropic zoonotic pathogen, to uncover a novel mechanism by which coronaviruses exploit PANoptosis to facilitate viral egress. We demonstrate that PDCoV infection triggers PANoptosis in intestinal epithelial cells, leading to plasma membrane rupture and subsequent viral release. Importantly, we identified the host ubiquitin-editing enzyme A20 as a critical negative regulator of this process. A20 restricts PANoptosome assembly by specifically deubiquitinating RIPK3, thereby limiting cell lysis and suppressing viral dissemination without affecting viral replication. Our findings offer fundamental insights into coronavirus-host interactions and highlight the therapeutic potential of targeting lytic cell death to combat viral dissemination.
Lu et al. (Tue,) studied this question.