1. DC-SIGN of Largemouth Bass ( Micropterus salmoides ) Mediates Immune Functions against Aeromonas hydrophila through Collaboration with the TLR Signaling Pathway.
- Author
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Huang M, Liu J, Yuan Z, Xu Y, Guo Y, Yang S, and Fei H
- Subjects
- Animals, Fish Proteins metabolism, Fish Proteins genetics, Fish Proteins immunology, Gram-Negative Bacterial Infections immunology, Gram-Negative Bacterial Infections metabolism, Gram-Negative Bacterial Infections microbiology, Immunity, Innate, Lectins, C-Type metabolism, Lectins, C-Type genetics, Lectins, C-Type immunology, Pathogen-Associated Molecular Pattern Molecules metabolism, Pathogen-Associated Molecular Pattern Molecules immunology, Receptors, Cell Surface metabolism, Receptors, Cell Surface genetics, Toll-Like Receptors metabolism, Toll-Like Receptors genetics, Aeromonas hydrophila immunology, Bass immunology, Bass metabolism, Bass microbiology, Bass genetics, Cell Adhesion Molecules metabolism, Cell Adhesion Molecules genetics, Fish Diseases immunology, Fish Diseases microbiology, Fish Diseases metabolism, Signal Transduction
- Abstract
C-type lectins in organisms play an important role in the process of innate immunity. In this study, a C-type lectin belonging to the DC-SIGN class of Micropterus salmoides was identified. MsDC-SIGN is classified as a type II transmembrane protein. The extracellular segment of MsDC-SIGN possesses a coiled-coil region and a carbohydrate recognition domain (CRD). The key amino acid motifs of the extracellular CRD of MsDC-SIGN in Ca
2+ -binding site 2 were EPN (Glu-Pro-Asn) and WYD (Trp-Tyr-Asp). MsDC-SIGN-CRD can bind to four pathogen-associated molecular patterns (PAMPs), including lipopolysaccharide (LPS), glucan, peptidoglycan (PGN), and mannan. Moreover, it can also bind to Gram-positive, Gram-negative bacteria, and fungi. Its CRD can agglutinate microbes and displays D-mannose and D-galactose binding specificity. MsDC-SIGN was distributed in seven tissues of the largemouth bass, among which the highest expression was observed in the liver, followed by the spleen and intestine. Additionally, MsDC-SIGN was present on the membrane of M . salmoides leukocytes, thereby augmenting the phagocytic activity against bacteria. In a subsequent investigation, the expression patterns of the MsDC-SIGN gene and key genes associated with the TLR signaling pathway (TLR4, NF-κB, and IL10) exhibited an up-regulated expression response to the stimulation of Aeromonas hydrophila . Furthermore, through RNA interference of MsDC-SIGN, the expression level of the DC-SIGN signaling pathway-related gene (RAF1) and key genes associated with the TLR signaling pathway (TLR4, NF-κB, and IL10) was decreased. Therefore, MsDC-SIGN plays a pivotal role in the immune defense against A . hydrophila by modulating the TLR signaling pathway.- Published
- 2024
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