Macrophage migration inhibitory factor inhibits osteoclastogenesis.
MIF is an important regulator of innate and adaptive immunity, which is produced by a variety of cell types including activated T cells and macrophages. We examined the effects of MIF on osteoclastogenesis in bone marrow (BM) cultures from WT and MIF-deficient (KO) mice as well as the bone mass of MIF KO mice. Exogenous MIF inhibited osteoclast formation in BM cultures by decreasing fusion in cells that were treated with M-CSF and RANKL. However, inhibition of OCL formation by MIF treatment was not mediated by fusion-related molecules in heterogeneous bone marrow cultures. BM cultures from MIF KO mice that were treated with M-CSF and RANKL, PTH or vitamin D had significantly increased OCL number compared to cells from WT mice. MIF also significantly inhibited OCL formation in cultures of RAW 264.7 cells that were treated with RANKL. In addition, the number of CFU-GM and Mac-1(+) cells in the BM of MIF KO mice was greater than in WT controls. Trabecular bone volume (TBV) in the femurs and vertebrae of MIF KO mice was decreased compared to WT mice. In addition, serum bone resorption and formation markers were decreased in MIF KO mice compared to WT mice. These results demonstrate that MIF has inhibitory effects on OCL formation in vitro. We also found that BM cell cultures from MIF KO mice had an increased capacity to form osteoclasts. Furthermore, MIF KO animals had significantly decreased TBV with low turnover. We conclude that MIF is an inhibitor of osteoclastogenesis in vitro, which may regulate bone turnover via indirect mechanism in vivo.
Jacquin
Claire
C
Center for Immunotherapy, University of Connecticut Health Center, Farmington, CT, USA.
Koczon-Jaremko
Boguslawa
B
Aguila
Hector L
HL
Leng
Lin
L
Bucala
Richard
R
Kuchel
George A
GA
Lee
Sun-Kyeong
SK
D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000187:drug effects; D015415:Biomarkers / Q000378:metabolism; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects; D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D008263:Macrophage Migration-Inhibitory Factors / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D015675:Osteocalcin / Q000097:blood; D010010:Osteoclasts / Q000166:cytology* / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects; D053244:Osteoprotegerin / Q000235:genetics / Q000378:metabolism; D053245:RANK Ligand / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055114:X-Ray Microtomography
D015415:Biomarkers; D008263:Macrophage Migration-Inhibitory Factors; D053244:Osteoprotegerin; D053245:RANK Ligand; D015675:Osteocalcin; D016173:Macrophage Colony-Stimulating Factor