In:
The Journal of Immunology, The American Association of Immunologists, Vol. 185, No. 10 ( 2010-11-15), p. 5926-5934
Abstract:
IL-1β is a key mediator of bone resorption in inflammatory settings, such as rheumatoid arthritis (RA). IL-1β promotes osteoclastogenesis by inducing RANKL expression on stromal cells and synergizing with RANKL to promote later stages of osteoclast differentiation. Because IL-1Rs share a cytosolic Toll–IL-1R domain and common intracellular signaling molecules with TLRs that can directly inhibit early steps of human osteoclast differentiation, we tested whether IL-1β also has suppressive properties on osteoclastogenesis in primary human peripheral blood monocytes and RA synovial macrophages. Early addition of IL-1β, prior to or together with RANKL, strongly inhibited human osteoclastogenesis as assessed by generation of TRAP+ multinucleated cells. IL-1β acted directly on human osteoclast precursors (OCPs) to strongly suppress expression of RANK, of the costimulatory triggering receptor expressed on myeloid cells 2 receptor, and of the B cell linker adaptor important for transmitting RANK-induced signals. Thus, IL-1β rendered early-stage human OCPs refractory to RANK stimulation. Similar inhibitory effects of IL-1β were observed using RA synovial macrophages. One mechanism of RANK inhibition was IL-1β–induced proteolytic shedding of the M-CSF receptor c-Fms that is required for RANK expression. These results identify a homeostatic function of IL-1β in suppressing early OCPs that contrasts with its well-established role in promoting later stages of osteoclast differentiation. Thus, the rate of IL-1–driven bone destruction in inflammatory diseases, such as RA, can be restrained by its direct inhibitory effects on early OCPs to limit the extent of inflammatory osteolysis.
Type of Medium:
Online Resource
ISSN:
0022-1767
,
1550-6606
DOI:
10.4049/jimmunol.1001591
Language:
English
Publisher:
The American Association of Immunologists
Publication Date:
2010
detail.hit.zdb_id:
1475085-5
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