AUTHOR=Zhao Yanjing , Zhang Jie , Qiao Dan , Gao Feng , Gu Yanlong , Jiang Xinyu , Zhu Lei , Kong Xianghui 

TITLE=CcGSDMEa functions the pore-formation in cytomembrane and the regulation on the secretion of IL-lβ in common carp (Cyprinus carpio haematopterus)

JOURNAL=Frontiers in Immunology

VOLUME=13

YEAR=2023

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.1110322

DOI=10.3389/fimmu.2022.1110322

ISSN=1664-3224

ABSTRACT=<p>GSDME is the only direct executor of caspase-dependent pyroptosis in both canonical and non-canonical inflammasomes known to date in fish, and plays an important role in anti-bacterial infection and inflammatory response. In order to determine the regulation of GSDMEa on antibacterial infection in innate immune response, the <italic>CcGSDMEa</italic> gene in common carp (<italic>Cyprinus carpio haematopterus</italic>) was first identified and characterized, and then its function related to immune defense was investigated. Our results showed that the expressions of <italic>Cc</italic>GSDMEa at the mRNA and protein levels were both significantly increased after <italic>Aeromonas hydrophila</italic> intraperitoneal infection at the early stage than that in the control group. We found that <italic>Cc</italic>GSDMEa could be cleaved by inflammatory caspase (<italic>Cc</italic>Caspase-1b) and apoptotic caspases (<italic>Cc</italic>Caspase-3a/b and <italic>Cc</italic>Caspase-7a/b). Interestingly, only the <italic>Cc</italic>GSDMEa-NT (1-252 aa) displayed bactericidal activity to <italic>Escherichia coli</italic> and could punch holes in the membrane of HEK293T cells, whereas <italic>Cc</italic>GSDMEa-FL (1-532 aa) and <italic>Cc</italic>GSDMEa-CT (257-532 aa) showed no above activity and pore-forming ability. Overexpression of <italic>Cc</italic>GSDMEa increased the secretion of <italic>Cc</italic>IL-1β and the release of LDH, and could reduce the <italic>A. hydrophila</italic> burdens in fish. On the contrary, knockdown of <italic>Cc</italic>GSDMEa reduced the secretion of <italic>Cc</italic>IL-1β and the release of LDH, and could increase the <italic>A. hydrophila</italic> burdens in fish. Taken together, the elevated expression of <italic>Cc</italic>GSDMEa was a positive immune response to <italic>A. hydrophila</italic> challenge in fish. <italic>Cc</italic>GSDMEa could perform the pore-formation in cell membrane and the regulation on the secretion of IL-lβ, and further regulate the bacterial clearance <italic>in vivo</italic>. These results suggested that <italic>Cc</italic>GSDMEa played an important role in immune defense against <italic>A. hydrophila</italic> and could provide a new insight into understanding the immune mechanism to resist pathogen invasion in teleost.</p>