Mitochondrial Membrane Potential Assay

Mitochondrial membrane potential was detected using mitochondrial membrane potential assay kit (Beyotime, Shanghai, China), according to the manufacturer’s instructions. Briefly, the cells were mock-infected or infected with picornavirus and collected and stained with JC-1 (1:200) at 37°C for 30 min. JC-1 fluorescence was tested at 514–529 nm (green fluorescence, JC-1 monomers) and 585–590 nm (red fluorescence, JC-1 aggregates) using a spectrofluorometer (Thermo Scientific). JC-1 fluorescence images were visualized using a Nikon Eclipse 80i fluorescence microscope. The images were captured using NIS Elements F 2.30 software. The occurrence of JC-1 green fluorescence indicates mitochondrial depolarization.