Chicken GSDME, a major pore-forming molecule responsible for RNA virus-induced pyroptosis in chicken

Pyroptosis is an inflammatory type of programmed cell death that mainly depends on the formation of plasma membrane pores by Gasdermin D (GSDMD) in mammals. However, the genetic deficiency of GSDMD in chicken renders avian pyroptosis elusive. Here, we show that infection of DF-1 cells (a chicken cell line) with infectious bursal disease virus (IBDV) induced cell death associated with chicken GSDME (chGSDME) cleavage, and so did cells with other RNA virus (VSV, AIV, or NDV) infections, indicating a broad role of chGSDME in RNA virus-induced pyroptosis in chicken. Furthermore, infection of DF-1 cells by IBDV or treatment of cells with Poly(I:C) initiated MDA5-mediated signaling pathway, followed by the activation of chCaspase-3/7 cleaving chGSDME at a specific site 270DAVD273. Moreover, knockdown or knockout of chGSDME expression in cells markedly reduced IBDV-induced pyroptosis and viral release. These results unravel the mechanisms of pyroptosis in chickens with RNA virus infection, providing important clues to uncover the role of GSDM proteins of different species in host response against pathogenic infection.IMPORTANCEPyroptosis is an inflammatory type of programmed cell death that mainly depends on the function of GSDMD in mammals and plays a crucial role in the pathogenesis of viral infection, whereas the mechanism of pyroptosis in chicken remains elusive. Herein, we show that IBDV and other RNA virus induced pyroptosis through the chMDA5-CASP8/9-CASP3/7-chGSDME pathway. The finding advances our understanding of GSDM proteins of different species in host response against pathogenic infection.