Zebrafish gasdermin E cleavage-engaged pyroptosis by inflammatory and apoptotic caspases

As the executor of pyroptosis known to date, gasdermins (GSDMs), consists of GSDMA, GSDMB, GSDMC, GSDMD, GSDME and pejvakin, might play critical roles in anti-bacterial infection as well as inflammatory diseases. However, zebrafish only harbors a pair of Gsdme (Gsdmea/b), and their activation mechanisms remain largely unknown. Herein, we investigate the activation mechanism of Gsdmea/b cleaved by inflammatory and apoptotic caspases in zebrafish，and found that Gsdmea/b are equally cleaved by Caspase 19b, a sister of Caspy2, but not Caspy. Moreover, the zebrafish apoptotic effector caspases, including Caspase 3a/b and Caspase 7, also can cleave Gsdmea/b at the same sites as inflammatory caspases recognized. Importantly, our results reveal that Caspase 8a/b can cleave Gsdmeb, but only Caspase 8a can cleave Gsdmea. Taken together, these findings suggest that zebrafish Gsdmea/b can concurrently function as GSDMD and GSDME in mammals, which will contribute to better understanding the mechanism of pyroptosis activation in teleost, as well as provide a clue for drug screening model against inflammatory diseases.