MLKL and Zika virus infectious disease: To assess whether cell death was caused by ZIKV infection in placental tissue, we further examined the activation of molecules key to various forms of programmed cell death, such as caspase-1, GSDMD, GSDME, and NLRP3 for pyroptosis, caspase-3 and caspase-8 for apoptosis, and MLKL phosphorylation and RIPK3 phosphorylation for necroptosis activation (33).