title: Inhibition of Drynariae Rhizoma extracts on bone resorption mediated by processing of cathepsin K in cultured mouse osteoclasts.
abstract: In the traditional Korean medicine, Drynariae Rhizoma (DR) [Drynaria fortunei (kunze) J. Sm] has been reported as a good enhancer for bone healing. In this experiment, we investigate the effects of DR on bone resorption using the bone cells culture. Different concentrations of crude extract of DR were added to mouse bone cells culture. The mitochondria activity of the bone cells after exposure was determined by colorimetric MTT assay. It was demonstrated that DR has potential effects on the bone cells culture without any cytotoxicity. The most effective concentration of DR on bone cells was 100 micro g/ml. On the other hand, cathepsin K (Cat K) is the major cysteine protease expressed in osteoclasts and is thought to play a key role in matrix degradation during bone resorption. In this study, Mouse long bone cells including osteoclasts and osteoblast were treated with the PI3-kinase inhibitor, wortmannin (WT), and a specific inhibitor of protein kinase C (PKC), calphostin C. Although WT prevented the osteoclast-mediated intracellular processing of Cat K, calphostin C did not. Similarly, treatment of osteoclasts-containing long bone cells with Drynariae Rhizoma (DR) extracts prevented the intracellular maturation of Cat K, suggesting that DR may disrupt the intracellular trafficking of pro Cat K. This is similar to that of WT. Since secreted proenzymes have the potential to reenter the cell via mannose-6-phosphate (M6P) receptor, to prevent this possibility, we tested WT and DR in the absence or presence of M6P. Inhibition of Cat K processing by WT or DR was observed in a dose-dependent manner. Furthermore, the addition of M6P resulted in enhanced potency of WT and DR. DR dose-dependently inhibited in vitro bone resorption with a potency similar to that observed for inhibition of Cat K processing.
authors.affiliation: National Research Laboratory for Glycobiology, Korean Ministry of Science and Technology, and Department of Biochemistry, Molecular Biology and Internal Medicine, College of Oriental Medicine, Dongguk University, Kyungbuk Kyungju, 780-714, South Korea.
authors.forename: Ji-Cheon
authors.initials: JC
authors.lastname: Jeong
authors.forename: Sung-Koo
authors.initials: SK
authors.lastname: Kang
authors.forename: Cheol-Ho
authors.initials: CH
authors.lastname: Youn
authors.forename: Chang-Whan
authors.initials: CW
authors.lastname: Jeong
authors.forename: Hyung-Min
authors.initials: HM
authors.lastname: Kim
authors.forename: Young-Choon
authors.initials: YC
authors.lastname: Lee
authors.forename: Young-Chae
authors.initials: YC
authors.lastname: Chang
authors.forename: Cheorl-Ho
authors.initials: CH
authors.lastname: Kim
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D001862:Bone Resorption / Q000201:enzymology / Q000517:prevention & control; D056657:Cathepsin K; D002403:Cathepsins / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D018920:Coculture Techniques / Q000379:methods; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004792:Enzyme Precursors / Q000187:drug effects / Q000378:metabolism; D005260:Female; D008297:Male; D008358:Mannose / Q000031:analogs & derivatives* / Q000494:pharmacology; D051379:Mice; D009281:Naphthalenes / Q000494:pharmacology; D010006:Osteoblasts / Q000187:drug effects; D010010:Osteoclasts / Q000187:drug effects* / Q000201:enzymology; D010936:Plant Extracts / Q000494:pharmacology* / Q000627:therapeutic use; D029621:Polypodiaceae / Q000737:chemistry*; D011233:Precipitin Tests; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D004791:Enzyme Inhibitors; D004792:Enzyme Precursors; D009281:Naphthalenes; D010936:Plant Extracts; C047533:mannose 6-sulfate; D011493:Protein Kinase C; D002403:Cathepsins; D056657:Cathepsin K; C534132:Ctsk protein, mouse; C058819:calphostin C; D008358:Mannose; D000077191:Wortmannin