Scavenging of soluble and immobilized CCL21 by ACKR4 regulates peripheral dendritic cell emigration

Leukocyte homing driven by the chemokine CCL21 is pivotal for adaptive immunity because it controls dendritic cell (DC) and T cell migration through CCR7. ACKR4 scavenges CCL21 and has been shown to play an essential role in DC trafficking at the steady state and during immune responses to tumors and cutaneous inflammation. However, the mechanism by which ACKR4 regulates peripheral DC migration is unknown, and the extent to which it regulates CCL21 in steady-state skin and lymph nodes (LNs) is contested. Specifically, our previous findings that CCL21 levels are increased in LNs of ACKR4-deficient mice [I. Comerford et al., Blood 116, 4130-4140 (2010)] were refuted [M. H. Ulvmar et al., Nat. Immunol. 15, 623-630 (2014)], and no differences in CCL21 levels in steady-state skin of ACKR4-deficient mice were reported despite compromised CCR7-dependent DC egress in these animals [S. A. Bryce et al., J. Immunol. 196, 3341-3353 (2016)]. Here, we resolve these issues and reveal that two forms of CCL21, full-length immobilized and cleaved soluble CCL21, exist in steady-state barrier tissues, and both are regulated by ACKR4. Without ACKR4, extracellular CCL21 gradients in barrier sites are saturated and nonfunctional, DCs cannot home directly to lymphatic vessels, and excess soluble CCL21 from peripheral tissues pollutes downstream LNs. The results identify the mechanism by which ACKR4 controls DC migration in barrier tissues and reveal a complex mode of CCL21 regulation in vivo, which enhances understanding of functional chemokine gradient formation.

Medienart:

E-Artikel

Erscheinungsjahr:

2021

Erschienen:

2021

Enthalten in:

Zur Gesamtaufnahme - volume:118

Enthalten in:

Proceedings of the National Academy of Sciences of the United States of America - 118(2021), 17 vom: 27. Apr.

Sprache:

Englisch

Beteiligte Personen:

Bastow, Cameron R [VerfasserIn]
Bunting, Mark D [VerfasserIn]
Kara, Ervin E [VerfasserIn]
McKenzie, Duncan R [VerfasserIn]
Caon, Adriana [VerfasserIn]
Devi, Sapna [VerfasserIn]
Tolley, Lynn [VerfasserIn]
Mueller, Scott N [VerfasserIn]
Frazer, Ian H [VerfasserIn]
Harvey, Natasha [VerfasserIn]
Condina, Mark R [VerfasserIn]
Young, Clifford [VerfasserIn]
Hoffmann, Peter [VerfasserIn]
McColl, Shaun R [VerfasserIn]
Comerford, Iain [VerfasserIn]

Links:

Volltext

Themen:

Ackr4 protein, mouse
Atypical chemokine receptors
Chemokine CCL21
Chemokines
Dendritic cells
Journal Article
Migration
Receptors, CCR
Research Support, Non-U.S. Gov't
Video-Audio Media

Anmerkungen:

Date Completed 30.11.2021

Date Revised 26.02.2024

published: Print

Citation Status MEDLINE

doi:

10.1073/pnas.2025763118

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM324301855