title: Monitoring and cell-specific deletion of C5aR1 using a novel floxed GFP-C5aR1 reporter knock-in mouse.
abstract: Many of the biological properties of C5a are mediated through activation of its receptor (C5aR1), the expression of which has been demonstrated convincingly on myeloid cells, such as neutrophils, monocytes, and macrophages. In contrast, conflicting results exist regarding C5aR1 expression in dendritic cells (DCs) and lymphoid lineage cells. In this article, we report the generation of a floxed GFP-C5aR1 reporter knock-in mouse. Using this mouse strain, we confirmed strong C5aR1 expression in neutrophils from bone marrow, blood, lung, and spleen, as well as in peritoneal macrophages. Further, we show C5aR1 expression in lung eosinophils, lung- and lamina propria-resident and alveolar macrophages, bone marrow-derived DCs, and lung-resident CD11b(+) and monocyte-derived DCs, whereas intestinal and pulmonary CD103(+) DCs stained negative. Also, some splenic NKT cells expressed GFP, whereas naive NK cells and B2 cells lacked GFP expression. Finally, we did not observe any C5aR1 expression in naive or activated CD4(+) Th cells in vitro or in vivo. Mating the floxed GFP-C5aR1 mouse strain with LysMCre mice, we were able to specifically delete C5aR1 in neutrophils and macrophages, whereas C5aR1 expression was retained in DCs. In summary, our findings suggest that C5aR1 expression in mice is largely restricted to cells of the myeloid lineage. The novel floxed C5aR1 reporter knock-in mouse will prove useful to track C5aR1 expression in experimental models of acute and chronic inflammation and to conditionally delete C5aR1 in immune cells.
authors.affiliation: Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany;
authors.forename: Christian M
authors.initials: CM
authors.lastname: Karsten
authors.affiliation: Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany;
authors.forename: Yves
authors.initials: Y
authors.lastname: Laumonnier
authors.affiliation: Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany;
authors.forename: Benjamin
authors.initials: B
authors.lastname: Eurich
authors.affiliation: Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany;
authors.forename: Fanny
authors.initials: F
authors.lastname: Ender
authors.affiliation: Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany;
authors.forename: Katharina
authors.initials: K
authors.lastname: Bröker
authors.affiliation: Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany;
authors.forename: Sreeja
authors.initials: S
authors.lastname: Roy
authors.affiliation: Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany;
authors.forename: Anna
authors.initials: A
authors.lastname: Czabanska
authors.affiliation: Cell Analysis Core, University of Lübeck, 23538 Lübeck, Germany; and.
authors.forename: Tillman
authors.initials: T
authors.lastname: Vollbrandt
authors.affiliation: Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany;
authors.forename: Julia
authors.initials: J
authors.lastname: Figge
authors.affiliation: Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany; Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229 joerg.koehl@uksh.de.
authors.forename: Jörg
authors.initials: J
authors.lastname: Köhl
mesh_terms: D000818:Animals; D002469:Cell Separation; D005434:Flow Cytometry; D055879:Gene Knock-In Techniques; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D022423:Myeloid Cells / Q000276:immunology* / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D044087:Receptor, Anaphylatoxin C5a / Q000032:analysis / Q000096:biosynthesis* / Q000276:immunology
chemical_list: C000591759:C5ar1 protein, mouse; D044087:Receptor, Anaphylatoxin C5a; D049452:Green Fluorescent Proteins