title: Inhibition of osteoblastic differentiation by warfarin and 18-α-glycyrrhetinic acid.
abstract: Anticoagulation therapy with vitamin K antagonists such as warfarin is widely used to prevent and treat stroke in patients with chronic atrial fibrillation or mechanical heart valves. Because vitamin K is an essential factor for ggg-carboxylation of osteocalcin, vitamin K antagonists might cause bone loss. Although the association between warfarin use and bone metabolism is still controversial, several studies show that bone mineral density is decreased and fracture risk is increased with warfarin therapy. Meanwhile, attenuation of gap junctional communication (GJC) by warfarin is reported in rat liver epithelial cells. However, the effect of warfarin on osteoblasts, in which GJC is important for osteoblastic differentiation, remains unknown. Here we investigated whether warfarin has an inhibitory effect on osteoblastic differentiation using an osteoblastic cell line (C2C12). Warfarin and 18-α-glycyrrhetinic acid (AGA), which is known as a nontoxic reversible GJC inhibitor, had the same effect on osteoblastic differentiation. Warfarin and AGA inhibited the bone morphogenetic protein (BMP)2-induced mRNA levels of alkaline phosphatase (ALP), collagen I α1, osteocalcin (OC) and osterix, which are specific markers for osteoblastic differentiation, in a dose-dependent manner. Moreover, the activities of OC- and ALP-luciferase reporters, which are induced by BMP2, and the transcriptional activity of Runx2 on OC and ALP promoters were inhibited by warfarin and AGA. The amount and activity of ALP induced by BMP2 were also decreased by warfarin and AGA. These results suggest that warfarin and AGA, a GJC inhibitor, have an inhibitory effect on osteoblastic differentiation.
authors: College of Pharmacy and Research Institute of Drug Development, Chonnam National University, Gwangju 500-757, Korea.
authors: Hyung Min
authors: HM
authors: Jeong
authors: Dong Hyeok
authors: DH
authors: Cho
authors: Yun Hye
authors: YH
authors: Jin
authors: Jin Ook
authors: JO
authors: Chung
authors: Min Young
authors: MY
authors: Chung
authors: Dong Jin
authors: DJ
authors: Chung
authors: Kwang Youl
authors: KY
authors: Lee
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology*; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D004847:Epithelial Cells; D017629:Gap Junctions / Q000378:metabolism; D006034:Glycyrrhetinic Acid / Q000494:pharmacology*; D008099:Liver; D008156:Luciferases / Q000378:metabolism; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D015675:Osteocalcin / Q000378:metabolism; D051381:Rats; D014162:Transfection; D014859:Warfarin / Q000494:pharmacology*
chemical_list: D000925:Anticoagulants; D055396:Bone Morphogenetic Protein 2; D015675:Osteocalcin; D014859:Warfarin; D008156:Luciferases; D000469:Alkaline Phosphatase; D006034:Glycyrrhetinic Acid