A degradatory fate for CCR4 suggests a primary role in Th2 inflammation
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Published version
Author(s)
Type
Journal Article
Abstract
CCR4 is the sole receptor for the chemokines CCL22 and CCL17. Clinical studies of asthmatic airways have shown levels of both ligands and CCR4+ Th2 cells to be elevated, suggestive of a role in disease. Consequently, CCR4 has aroused much interest as a potential therapeutic target and an understanding of how its cell surface expression is regulated is highly desirable. To this end, receptor expression, receptor endocytosis, and chemotaxis were assessed using transfectants expressing CCR4, CCR4+ human T cell lines, and human Th2 cells polarized in vitro. CCL17 and CCL22 drove rapid endocytosis of CCR4 in a dose‐dependent manner. Replenishment at the cell surface was slow and sensitive to cycloheximide, suggestive of de novo synthesis of CCR4. Constitutive CCR4 endocytosis was also observed, with the internalized CCR4 found to be significantly degraded over a 6‐h incubation. Truncation of the CCR4 C‐terminus by 40 amino acids had no effect on cell surface expression, but resulted in significant impairment of ligand‐induced endocytosis. Consequently, migration to both CCL17 and CCL22 was significantly enhanced. In contrast, truncation of CCR4 did not impair constitutive endocytosis or degradation, suggesting the use of alternative receptor motifs in these processes. We conclude that CCR4 cell surface levels are tightly regulated, with a degradative fate for endocytosed receptor. We postulate that this strict control is desirable, given that Th2 cells recruited by CCR4 can induce the further expression of CCR4 ligands in a positive feedback loop, thereby enhancing allergic inflammation.
Date Issued
2020-03-01
Date Acceptance
2020-01-10
Citation
Journal of Leukocyte Biology, 2020, 107 (3), pp.455-466
ISSN
0741-5400
Publisher
Wiley
Start Page
455
End Page
466
Journal / Book Title
Journal of Leukocyte Biology
Volume
107
Issue
3
Copyright Statement
© 2020 The Authors. Journal of Leukocyte Biology published by Wiley Periodicals, Inc. on behalf of Society for Leukocyte Biology
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Sponsor
Medical Research Council (MRC)
Grant Number
G1000758
Subjects
Science & Technology
Life Sciences & Biomedicine
Cell Biology
Hematology
Immunology
chemokine receptor
chemokine
chemotaxis
endocytosis
Th2 lymphocyte
CHEMOKINE RECEPTOR CCR4
MACROPHAGE-DERIVED CHEMOKINE
GENE-RELATED PEPTIDE
INTERNALIZATION
EXPRESSION
CELLS
GLYCOSYLATION
ACTIVATION
LIGAND
IDENTIFICATION
Th2 lymphocyte
chemokine
chemokine receptor
chemotaxis
endocytosis
0601 Biochemistry and Cell Biology
1107 Immunology
Immunology
Publication Status
Published
Date Publish Online
2020-02-13