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Published on: August 10, 2021
Peptidoglycan recognition protein MsPGRP in largemouth bass (Micropterus salmoides) mediates immune functions with
Mengmeng Huang1, Taiwei Dong2, Xiaocong Lou2
1College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, 310018, China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
Abstract:
Peptidoglycan (PGN) recognition proteins (PGRPs) are important immune factors in innate immunity that function in recognising pathogens and activating the immune system. These ubiquitous proteins are conserved in invertebrates and vertebrates. In this study, a PGRP gene (MsPGRP) from largemouth bass (Micropterus salmoides) was identified and characterised, and its transcription distribution was explored. Recombinant protein (rMsPGRP) exhibited dose-dependent binding to PGN and glucan (GLU), but weak binding to lipopolysaccharide (LPS). MsPGRP exhibited agglutinating activity against several Gram-negative bacteria, Gram-positive bacteria and fungi, and it promoted phagocytosis activity of leukocytes against Micrococcus luteus and Aeromonas hydrophila. The protein also possessed amidase activity in the presence of Zn2+, degraded PGN, and disrupted the M. luteus cell wall. The results suggest that MsPGRP plays an important role in pathogen recognition, and acts as a opsonin during immune system responses and elimination of invading pathogens.
Insights
Largemouth bass peptidoglycan recognition proteins (PGRPs) bind pathogens and activate innate immunity. This study identifies MsPGRP, demonstrating its role in pathogen recognition, opsonization, and pathogen elimination.
Area of Science:
- Immunology
- Molecular Biology
- Fish Science
Background:
- Peptidoglycan (PGN) recognition proteins (PGRPs) are crucial for innate immunity, recognizing pathogens and activating immune responses.
- PGRPs are conserved across invertebrates and vertebrates, highlighting their fundamental role in host defense.
Purpose of the Study:
- To identify and characterize a PGRP gene (MsPGRP) from largemouth bass (Micropterus salmoides).
- To investigate the function of MsPGRP in pathogen recognition and immune response.
Main Methods:
- Gene identification and characterization of MsPGRP in largemouth bass.
- Recombinant protein expression and binding assays with PGN, glucan (GLU), and lipopolysaccharide (LPS).
- Assays for agglutinating activity, phagocytosis promotion, and amidase activity.
Main Results:
- Recombinant MsPGRP showed dose-dependent binding to PGN and GLU, with weak LPS binding.
- MsPGRP exhibited agglutinating activity against bacteria and fungi, and promoted leukocyte phagocytosis.
- MsPGRP demonstrated Zn2+-dependent amidase activity, degrading PGN and disrupting bacterial cell walls.
Conclusions:
- MsPGRP plays a significant role in pathogen recognition in largemouth bass.
- MsPGRP functions as an opsonin, enhancing the immune system's response and elimination of pathogens.
