The activated beta-integrin (Cg beta V) enhances RGD-binding and phagocytic capabilities of hemocytes in Crassostrea gigas

Integrins are an important family of cell receptors that can bind foreign particles and promote cell phagocytosis after they are activated. In the present study, a novel beta integrin was identified from pacific oyster Crassostrea gigas with an extracellular domain, a single transmembrane segment, a...

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Bibliographic Details
Published in:Fish & Shellfish Immunology
Main Authors: Lv, Zhao, Qiu, Limei, Jia, Zhihao, Wang, Weilin, Liu, Zhaoqun, Wang, Lingling, Song, Linsheng
Format: Report
Language:English
Published: ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD 2019
Subjects:
C. gigas
RGD-Binding
Integrin activation
Integrin-mediated phagocytosis
Fisheries
Immunology
Marine & Freshwater Biology
Veterinary Sciences
STRUCTURAL BASIS
GENE-EXPRESSION
PROTEIN
ADHESION
RECOGNITION
TRANSDUCTION
COMPLEXITY
ATTACHMENT
EVOLUTION
RECEPTOR
Pacific
Crassostrea gigas
Pacific oyster
Online Access:http://ir.qdio.ac.cn/handle/337002/161136
https://doi.org/10.1016/j.fsi.2019.01.047
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Summary:Integrins are an important family of cell receptors that can bind foreign particles and promote cell phagocytosis after they are activated. In the present study, a novel beta integrin was identified from pacific oyster Crassostrea gigas with an extracellular domain, a single transmembrane segment, and a short cytoplasmic domain. It was phylogenetically clustered with phagocytosis-related insecta beta V, and designated as Cg beta V. Cg beta V shared a conserved NPX[Y/F] motif related to integrin activation with other phagocytosis-related beta integrins. The mRNA transcripts of Cg beta V were widely detected in oyster tissues including hemocytes, gonad, adductor muscle, mantle, gill, and hepatopancreas, and the expression level in hemocytes was significantly up-regulated at 12 h after lipopolysaccharide (LPS) stimulation (p < 0.05), which was 2.29-fold higher than that in the control group. Cg beta V proteins were mainly observed on the hemocytes surface. The oyster hemocytes were found to bind fluorescein isothiocyanate (FITC)-labeled Arg-Gly-Asp-containing peptides (RGDCPs), and the binding capability was significantly up-regulated with the peak percentage of 37.6% at 12 h post LPS stimulation, which was higher than that in the control group (8.8%, p < 0.05), suggesting the activation of RGD-binding integrins on oyster hemocytes surface. The label-free RGDCPs and anti-Cg beta V antibody inhibited the binding capability of hemocytes towards FITC-labeled RGDCPs, which were significant lower in RGD blocking group (7.4%, p < 0.05) and anti-Cg beta V blocking group (22.1%, p < 0.05) than that in the control group (37.6%), indicating that Cg beta V could be a RGD-binding integrin. Phagocytosis assay demonstrated that LPS could enhance the phagocytosis of hemocytes towards Escherichia cob and fluorescent beads with the phagocytic rate (PR) of 18.3% and 17.4%, and phagocytic index (PI) of 5.29 and 37.71, respectively, which were significant higher than that in the control group (11.0% and 3.65 for E. coli, ...

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