Role of ASC, a key component of the inflammasome in the antimicrobial process in black rockfish (Sebastes schlegelii)

• Published in: Fish & shellfish immunology 2024-11, Vol.154, p.109886, Article 109886
• Main Authors: Tao, Ze, Wang, Xuangang, Li, Hengshun, Zhou, Dianyang, Chen, Qiannan, Duan, Zhixiang, Zhang, Fan, Chen, Zhentao, Yu, Gan, Yu, Haiyang
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; ASC; CARD Signaling Adaptor Proteins - chemistry; CARD Signaling Adaptor Proteins - genetics; CARD Signaling Adaptor Proteins - immunology; E. piscicida; Edwardsiella - immunology; Edwardsiella - physiology; Enterobacteriaceae Infections - immunology; Enterobacteriaceae Infections - veterinary; Fish Diseases - immunology; Fish Proteins - chemistry; Fish Proteins - genetics; Fish Proteins - immunology; Fishes - genetics; Fishes - immunology; Gene Expression Profiling - veterinary; Gene Expression Regulation - immunology; Immunity, Innate - genetics; Inflammasome; Inflammasomes - genetics; Inflammasomes - immunology; Perciformes - genetics; Perciformes - immunology; Phylogeny; Sebastes schlegelii; Sequence Alignment - veterinary
• ISSN: 1050-4648; 1095-9947; 1095-9947
• DOI: 10.1016/j.fsi.2024.109886

Apoptosis-associated speck-like protein containing a CARD (ASC) serves as a pivotal component within the inflammasome complex, playing a critical role in the activation of the innate immune response against pathogenic infection. However, the functional significance of inflammasome ASC in teleosts remains unclear. In this study, the coding sequence (CDS) region of ASC gene of Sebastes schlegelii (SsASC) was cloned, and we observed a high conservation of SsASC with teleosts through comprehensive bioinformatics analysis. SsASC and SsCaspase-1 were found to be highly expressed in immune tissues such as spleen and head kidney. Furthermore, our findings revealed that SsASC interacts with SsCaspase-1 through CARD-CARD interactions to generate oligomeric speck-like structures, whereas the PYD structural domain of SsASC forms only filamentous structures. To further understand the role of SsASC in combating Edwardsiella piscicida (E. piscicida) infection, we developed a SsASC knockdown model using in vivo siRNA injection and E. piscicida challenge via intraperitoneal injection. The model demonstrated that E. piscicida infection up-regulated SsASC expression, which was markedly reduced upon SsASC knockdown. Concurrently, E. piscicida colonization was significantly enhanced in the knockdown group, accompanied by a suppression of inflammatory factor expression. These findings confirm the pivotal antibacterial and anti-infective role of SsASC in the Sebastes schlegelii immune response upon E. piscicida stimulation. Our study highlights the significance of SsASC in the innate immune defense mechanism of teleosts against bacterial pathogens. •ASC gene, the inflammasome component of black rockfish (Sebastes schlegelii), was identified.•The recruitment of SsCaspase-1 by SsASC via CARD-CARD was determined.•Knockdown of SsASC promotes the colonization of E. piscicida in black rockfish.•Knockdown of SsASC inhibits the expression level of inflammatory factors.