A class B scavenger receptor mediates antimicrobial peptide secretion and phagocytosis in Chinese mitten crab (Eriocheir sinensis)

Dev Comp Immunol. 2020 Feb:103:103496. doi: 10.1016/j.dci.2019.103496. Epub 2019 Sep 9.

Abstract

Scavenger receptors (SRs) are pattern recognition receptors (PRRs) vital for innate immunity. As well as their importance in immune recognition, microbe phagocytosis, and the clearance of modified endogenous molecules, they also activate downstream immune responses as co-receptors. In the current study, we identified a class B scavenger receptor in Eriocheir sinensis (EsSR-B2). The full-length gene is 2,517 bp and encodes a 517 amino acid polypeptide. EsSR-B2 is expressed widely in all tested tissues and is induced by microbial stimulation. Recombinant EsSR-B2 binds to bacteria and pathogen-associated molecular patterns in vitro. Upon knockdown of EsSR-B2 and bacterial challenge with Staphylococcus aureus or Vibrio parahaemolyticus, phagocytosis rates in hemocytes are decreased. Moreover, the expression of several antimicrobial peptides (AMPs) in response to distinct microorganism stimulation is decreased following EsSR-B2 silencing. Thus, EsSR-B2 is a PRR that protects E. sinensis against invading pathogens by promoting phagocytosis and enhancing AMP expression.

Keywords: Antimicrobial peptide secretion; Eriocheir sinensis; Phagocytosis; Scavenger receptor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antimicrobial Cationic Peptides / metabolism*
  • Arthropod Proteins / chemistry
  • Arthropod Proteins / genetics
  • Arthropod Proteins / metabolism*
  • Base Sequence
  • Brachyura / classification
  • Brachyura / genetics
  • Brachyura / immunology*
  • Brachyura / microbiology
  • Gene Expression Regulation / immunology
  • Hemocytes / immunology
  • Hemocytes / microbiology
  • Models, Molecular
  • Pathogen-Associated Molecular Pattern Molecules / metabolism
  • Phagocytosis*
  • Phylogeny
  • Protein Binding
  • Scavenger Receptors, Class B / chemistry
  • Scavenger Receptors, Class B / genetics
  • Scavenger Receptors, Class B / metabolism*
  • Sequence Alignment
  • Staphylococcus aureus / physiology
  • Tissue Distribution
  • Vibrio parahaemolyticus / physiology

Substances

  • Antimicrobial Cationic Peptides
  • Arthropod Proteins
  • Pathogen-Associated Molecular Pattern Molecules
  • Scavenger Receptors, Class B