title: Inflammatory monocytes and Fcγ receptor IV on osteoclasts are critical for bone destruction during inflammatory arthritis in mice.
abstract: Destruction of bone tissue by osteoclasts represents a severe pathological phenotype during inflammatory arthritis and results in joint pain and bone malformations. Previous studies have established the essential role of cytokines including TNFα and receptor-ligand interactions, such as the receptor activator of nuclear factor-kappa B-receptor activator of nuclear factor-kappa B ligand interaction for osteoclast formation during joint inflammation. Moreover, autoantibodies contribute to joint inflammation in inflammatory arthritis by triggering cellular fragment crystallizable (Fc)γ receptors (FcγR), resulting in the release of proinflammatory cytokines and chemokines essential for recruitment and activation of innate immune effector cells. In contrast, little is known about the expression pattern and function of different FcγRs during osteoclast differentiation. This would allow osteoclasts to directly interact with autoantibody immune complexes, rather than being influenced indirectly via proinflammatory cytokines released upon immune complex binding to other FcγR-expressing innate immune cells. To address this question, we studied FcγR expression and function on osteoclasts during the steady state and during acute joint inflammation in a model of inflammatory arthritis. Our results suggest that osteoclastogenesis is directly influenced by IgG autoantibody binding to select activating FcγRs on immature osteoclasts, resulting in enhanced osteoclast generation and, ultimately, bone destruction.
authors.affiliation: Institute of Genetics, Department of Biology, University of Erlangen-Nürnberg, 91058 Erlangen, Germany.
authors.forename: Michaela
authors.initials: M
authors.lastname: Seeling
authors.forename: Ulrike
authors.initials: U
authors.lastname: Hillenhoff
authors.forename: Jean Pierre
authors.initials: JP
authors.lastname: David
authors.forename: Georg
authors.initials: G
authors.lastname: Schett
authors.forename: Jan
authors.initials: J
authors.lastname: Tuckermann
authors.forename: Anja
authors.initials: A
authors.lastname: Lux
authors.forename: Falk
authors.initials: F
authors.lastname: Nimmerjahn
mesh_terms: D000818:Animals; D000950:Antigens, Ly / Q000378:metabolism; D001169:Arthritis, Experimental / Q000276:immunology* / Q000473:pathology; D001862:Bone Resorption / Q000276:immunology / Q000473:pathology*; D002454:Cell Differentiation; D007249:Inflammation / Q000276:immunology / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009000:Monocytes / Q000145:classification / Q000276:immunology* / Q000473:pathology; D010010:Osteoclasts / Q000276:immunology* / Q000473:pathology; D017452:Receptors, IgG / Q000172:deficiency / Q000235:genetics / Q000276:immunology*
chemical_list: D000950:Antigens, Ly; C522404:Fcgr4 protein, mouse; C494192:Ly-6C antigen, mouse; D017452:Receptors, IgG
keywords: Fc receptor; monocyte differentiation