title: Inhibitory effect of zinc-chelating dipeptide on parathyroid hormone-stimulated osteoclast-like cell formation in mouse marrow cultures: involvement of calcium signaling.
abstract: A possible mechanism of zinc action inhibiting the PTH-induced osteoclast-like cell formation in mouse marrow culture system in vitro was investigated. Bone marrow cells were cultured for 7 days in alpha-minimal essential medium containing a well-known bone-resorbing agent parathyroid hormone (1-34) (PTH). Osteoclast-like cell formation was estimated with staining for tartrate-resistant acid phosphatase (TRACP), a marker enzyme of osteoclasts. The effect of zinc sulfate (10(-6) M) or beta-alanyl-L-histidinato zinc (AHZ; 10(-6) M) inhibiting the PTH (10(-8) M)-induced osteoclast-like cell formation was clearly seen in the absence or presence of theophylline (10(-4) M). However, zinc compounds did not inhibit the stimulatory effect of dibutyryladenosine 3',5'-cyclic monophosphate (DBcAMP; 10(-4) M) on osteoclast-like cell formation. The stimulating effect of PTH (10(-8) M) on osteoclast-like cell formation was clearly weakened (about 50%) in the presence of EGTA (1.0 mM) or dibucaine (10(-5) M). Phorbol 12-myristate 13-acetate (PMA), a protein kinase C activator (10(-8) to 10(-6) M), clearly stimulated osteoclast-like cell formation. PMA effect was inhibited by the presence of AHZ (10(-6) M) or zinc sulfate (10(-8) M). However, the inhibitory effect of zinc compounds was not seen in the presence of both PTH (10(-8) M) and PMA (10(-6) M). The present findings suggest that zinc compounds inhibit PTH-stimulated osteoclast-like cell formation mediated through the Ca(2+)-dependent activation of protein kinase C.
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000187:drug effects*; D001854:Bone Marrow Cells; D002118:Calcium / Q000502:physiology*; D002336:Carnosine / Q000031:analogs & derivatives / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009942:Organometallic Compounds / Q000494:pharmacology; D010010:Osteoclasts / Q000187:drug effects*; D010281:Parathyroid Hormone / Q000037:antagonists & inhibitors*; D015398:Signal Transduction / Q000187:drug effects; D013268:Stimulation, Chemical; D013431:Sulfates / Q000494:pharmacology; D015032:Zinc; D017967:Zinc Compounds / Q000494:pharmacology; D019287:Zinc Sulfate
chemical_list: D002614:Chelating Agents; D009942:Organometallic Compounds; D010281:Parathyroid Hormone; D013431:Sulfates; D017967:Zinc Compounds; C061957:polaprezinc; D019287:Zinc Sulfate; D002336:Carnosine; D015032:Zinc; D002118:Calcium