The nonstructural protein 5 of coronaviruses antagonizes GSDMD-mediated pyroptosis by cleaving and inactivating its pore-forming p30 fragment

Coronaviruses (CoV) are a family of RNA viruses that typically cause respiratory, enteric and hepatic diseases in animals and humans. Here, we used porcine epidemic diarrhea virus (PEDV) as a model of coronaviruses (CoVs) to illustrate the reciprocal regulation between CoVs infection and pyroptosis. For the first time, we clarified the molecular mechanism of porcine Gasdermin D (pGSDMD)-mediated pyroptosis and demonstrated that amino acids T239 and F240 within pGSDMD-p30 are critical for pyroptosis. Furthermore, 3C-like protease Nsp5 from SARS-CoV-2, MERS-CoV, PDCoV and PEDV can cleave human/porcine GSDMD at the Q193-G194 junction upstream of the caspase-1 cleavage site to produce two fragments which fail to trigger pyroptosis or inhibit viral replication. Thus, we provide clear evidence that coronoviruses may utilize viral Nsp5-GSDMD pathway to help their host cells escaping from pyroptosis, protecting the replication of the virus during the initial period, which suggest an important strategy for coronoviruses infection and sustain.