Serum calcium-decreasing factor, caldecrin, inhibits osteoclast differentiation by suppression of NFATc1 activity.
Caldecrin/chymotrypsin C is a novel secretory-type serine protease that was originally isolated as a serum calcium-decreasing factor from the pancreas. Previously, we reported that caldecrin suppressed the bone-resorbing activity of rabbit mature osteoclasts (Tomomura, A., Yamada, H., Fujimoto, K., Inaba, A., and Katoh, S. (2001) FEBS Lett. 508, 454-458). Here, we investigated the effects of caldecrin on mouse osteoclast differentiation induced by macrophage-colony stimulating factor and the receptor activator of NF-kappaB ligand (RANKL) from the monocyte/macrophage cell lineage of bone marrow cells. Wild-type and protease-deficient mutant caldecrin dose-dependently inhibited RANKL-stimulated tartrate-resistant acid phosphatase-positive osteoclast formation from bone marrow cells. Caldecrin did not affect macrophage colony formation from monocyte/macrophage lineage cells or osteoclast progenitor generation in cultures of bone marrow cells. Caldecrin inhibited accumulation of the RANKL-stimulated nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) mRNA in bone marrow cells, which is a key transcription factor for the differentiation of osteoclasts. Caldecrin also suppressed RANKL-induced differentiation of the RAW264.7 monocyte/macrophage cell line into osteoclasts. Caldecrin reduced the transcriptional activity of NFATc1 in RAW264.7 cells, whereas those of NF-kappaB and c-Fos, which are also transcription factors involved in osteoclast differentiation, were unaffected. Caldecrin inhibited RANKL-stimulated nuclear translocation of NFATc1 and the activity of the calcium/calmodulin-dependent phosphatase, calcineurin. Caldecrin inhibited phospholipase Cgamma1-mediated Ca(2+) oscillation evoked by RANKL stimulation. RANKL-stimulated phosphorylation of spleen tyrosine kinase (Syk) was also attenuated by caldecrin. Taken together, these results indicate that caldecrin inhibits osteoclastogenesis, without its protease activity, by preventing a phospholipase Cgamma1-mediated Ca(2+)oscillation-calcineurin-NFATc1 pathway.
Hasegawa
Hiroya
H
Division of Biochemistry, Department of Oral Biology and Tissue Engineering, Meikai University, School of Dentistry, 1-1 Keyakidai, Sakado, Saitama 350-0283, Japan.
Kido
Seisui
S
Tomomura
Mineko
M
Fujimoto
Kengo
K
Ohi
Michi
M
Kiyomura
Masaru
M
Kanegae
Haruhide
H
Inaba
Akemi
A
Sakagami
Hiroshi
H
Tomomura
Akito
A
D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects; D019703:Calcineurin / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D015151:Immunoblotting; D047468:Immunoprecipitation; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008297:Male; D051379:Mice; D050778:NFATC Transcription Factors / Q000235:genetics / Q000378:metabolism*; D010010:Osteoclasts / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects / Q000235:genetics; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D053245:RANK Ligand / Q000494:pharmacology; D012697:Serine Endopeptidases / Q000494:pharmacology*; D018411:Spodoptera; D000072377:Syk Kinase
D047908:Intracellular Signaling Peptides and Proteins; D050778:NFATC Transcription Factors; D053245:RANK Ligand; D011505:Protein-Tyrosine Kinases; D000072377:Syk Kinase; C000606897:Syk protein, mouse; D019703:Calcineurin; D012697:Serine Endopeptidases; C074385:caldecrin; D002118:Calcium