Ochi S, Shinohara M, Sato K, Gober HJ, Koga T, Kodama T, Takai T, Miyasaka N, Takayanagi H. Pathological role of osteoclast costimulation in arthritis-induced bone loss.
Proc Natl Acad Sci U S A 2007;
104:11394-9. [PMID:
17592115 PMCID:
PMC2040909 DOI:
10.1073/pnas.0701971104]
[Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Indexed: 01/12/2023] Open
Abstract
Abnormal T cell immune responses induce aberrant expression of inflammatory cytokines such as TNF-alpha, leading to osteoclastmediated bone erosion and osteoporosis in autoimmune arthritis. However, the mechanism underlying enhanced osteoclastogenesis in arthritis is not completely understood. Here we show that TNF-alpha contributes to inflammatory bone loss by enhancing the osteoclastogenic potential of osteoclast precursor cells through inducing paired Ig-like receptor-A (PIR-A), a costimulatory receptor for receptor activator of NF-kappaB (RANK). In fact, bone erosion and osteoporosis, but not inflammation, caused by aberrant TNF-alpha expression were ameliorated in mice deficient in Fc receptor common gamma subunit or beta(2)-microglobulin, in which the expression of PIR-As and PIR-A ligands is impaired, respectively. These results establish the pathological role of costimulatory receptors for RANK in bone loss in arthritis and may provide a molecular basis for the future therapy of inflammatory diseases.
Collapse