title: CX3CR1-dependent endothelial margination modulates Ly6Chighmonocyte systemic deployment upon inflammation in mice.
abstract: Two subsets of blood monocytes are commonly described in mice and humans: the classical inflammatory monocytes, which are rapidly mobilized upon inflammation in a CC-chemokine receptor 2-dependent manner, and the nonclassical blood resident monocyte subset that patrols the intraluminal side of the endothelium. Old reports suggest that blood monocytes are distributed into circulating and marginating pools, but no direct evidence of the latter has been obtained so far. Using a combination of in vivo real-time imaging and blood/tissue partitioning by intravascular staining of leukocytes, we showed that both inflammatory and resident monocytes are retained in the bone marrow vasculature, representing an important reservoir of marginated monocytes. Upon lipopolysaccharide or cecal ligation and puncture-induced peritonitis, these marginated cells are rapidly released and recruited to the peritoneum membrane lumen vasculature where they reside through CX3C-chemokine receptor 1 (CX3CR1)-dependent adherence. At a later time point, inflammatory monocytes infiltrate the spleen parenchyma but remain mainly intravascular in the vicinity of the lungs and the peritoneum. Our results show that this monocyte deployment is controlled by a CX3CR1-dependent balance between marginating and circulating monocytes and highlight that tissue infiltration is not a mandatory fate for inflammatory monocytes.
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, INSERM UMR 1135, CNRS ERL8255, Centre d'Immunologie et des Maladies Infectieuses, Paris, France.
authors.forename: Pauline
authors.initials: P
authors.lastname: Hamon
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, INSERM UMR 1135, CNRS ERL8255, Centre d'Immunologie et des Maladies Infectieuses, Paris, France.
authors.forename: Pierre-Louis
authors.initials: PL
authors.lastname: Loyher
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, INSERM UMR 1135, CNRS ERL8255, Centre d'Immunologie et des Maladies Infectieuses, Paris, France.
authors.forename: Camille
authors.initials: C
authors.lastname: Baudesson de Chanville
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, INSERM UMR 1135, CNRS ERL8255, Centre d'Immunologie et des Maladies Infectieuses, Paris, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Licata
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, INSERM UMR 1135, CNRS ERL8255, Centre d'Immunologie et des Maladies Infectieuses, Paris, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Combadière
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, INSERM UMR 1135, CNRS ERL8255, Centre d'Immunologie et des Maladies Infectieuses, Paris, France.
authors.forename: Alexandre
authors.identifier: 0000-0002-7770-7210
authors.initials: A
authors.lastname: Boissonnas
mesh_terms: D000818:Animals; D000950:Antigens, Ly; D000073883:CX3C Chemokine Receptor 1; D002448:Cell Adhesion / Q000276:immunology; D002634:Chemotaxis, Leukocyte / Q000276:immunology*; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000276:immunology*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D007249:Inflammation / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009000:Monocytes / Q000166:cytology / Q000276:immunology*; D019707:Receptors, Chemokine / Q000276:immunology*
chemical_list: D000950:Antigens, Ly; D000073883:CX3C Chemokine Receptor 1; C471885:Cx3cr1 protein, mouse; C494192:Ly-6C antigen, mouse; D019707:Receptors, Chemokine