An effector caspase Sp-caspase first identified in mud crab Scylla paramamosain exhibiting immune response and cell apoptosis. Issue 103 (August 2020)

• Record Type: Journal Article
• Authors: Li, Jishan; Dong, Lixia; Zhu, Depeng; Zhang, Min; Wang, Kejian; Chen, Fangyi
• Is Part Of: Fish & shellfish immunology. Issue 103(2020)
• Page Start: 442
• Page End: 453
• Publication Date: 2020-08
• Subjects: Scylla paramamosain -- Sp-caspase -- Immune response -- Apoptosis; Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2020.05.045
• Languages: English
• ISSNs: 1050-4648

Abstract

Abstract: Apoptosis plays a key role in the immune defense against pathogen infection, and caspase is one of the most important protease enzyme families, which could initiate and execute apoptosis. Among crustaceans, several caspase genes have been reported. However, caspase in mud crab Scylla paramamosain, have not been identified yet. Here, in the present study, we characterized a new caspase, named as Sp-caspase, from S. paramamosain . The full-length cDNA sequence of Sp-caspase contained 966 bp open reading frame, encoding 322 amino acids, and its molecular weight was 36 kDa. This gene has three conserved domains of the caspase family, a prodomain, a large subunit P20 and a small subunit P10. Phylogenetic analysis showed that Sp-caspase was clustered into an effector caspase group. Sp-caspase mainly distributed in midgut, hepatopancreas, hemocytes and female ovaries, and the transcript was significantly regulated in different tissues after being challenged with Vibrio parahaemolyticus, Vibrio alginolyticus or LPS. After infection with V. alginolyticus, the apoptosis rate of hemocytes notably increased, while the mRNA level of Sp-caspase and hydrolysis activity of caspase 3/7 significantly decreased. Furthermore, in vitro assays showed that the recombinant protein t Sp -caspase (deletion of Sp -caspase prodomain) could efficiently recognize and cleave human caspase 3/7 substrate Ac-DEVD- p NA, functioning as an effector caspase. Meanwhile, heterologous expression of Sp -caspase in several cell lines (HEK293T cells, HeLa cells and HighFive cells) could specifically induce cell apoptosis. Taken together, these data demonstrated that Sp-caspase could perform apoptosis as an effector caspase. In addition, it might be a negative regulator of hemocytes apoptosis under pathogen infection, which would contribute to homeostasis and immune defense of hemocytes in S. paramamosain . Highlights: A new apoptosis related gene, Sp-caspase, was firstly characterized from mud crab Scylla paramamosain. Sp-caspase gene was highly expressed in midgut, hepatopancreas, hemocytes and female ovaries. Sp-caspase and apoptosis-related genes significantly responded to immune challenge. Vibrio alginolyticus infection would promote hemocytes apoptosis and reduce the hydrolysis activity of caspase 3/7. Recombinant t Sp -caspase acted as an effector caspase and heterologous expression of Sp-caspase could induce cell apoptosis.