RRC ID 19335
著者 Matsuguchi T, Chiba N, Bandow K, Kakimoto K, Masuda A, Ohnishi T.
タイトル JNK activity is essential for Atf4 expression and late-stage osteoblast differentiation.
ジャーナル J Bone Miner Res
Abstract Osteoblasts differentiate from mesodermal progenitors and play a pivotal role in bone formation and mineralization. Several transcription factors including runt-related transcription factor 2 (RUNX2), Osterix (OSX), and activating transcription factor4 (ATF4) are known to be crucial for the process, whereas the upstream signal transduction controlling the osteoblast differentiation sequence is largely unknown. Here, we explored the role of c-jun N-terminal kinase (JNK) in osteoblast differentiation using in vitro differentiation models of primary osteoblasts and MC3T3-E1 cells with ascorbic acid/beta-glycerophosphate treatment. Terminal osteoblast differentiation, represented by matrix mineralization, was significantly inhibited by the inactivation of JNK with its specific inhibitor and exogenous overexpression of MKP-M (MAP kinase phosphatase isolated from macrophages), which preferentially inactivates JNK. Conversely, enhanced mineral deposition was observed by inducible overexpression of p54(JNK2), whereas it was not observed by the overexpression of p46(JNK1) or p46(JNK2), indicating a distinct enhancing role of p54(JNK2) in osteoblast differentiation. Inactivation of JNK significantly inhibited late-stage molecular events of osteoblast differentiation, including gene expression of osteocalcin (Ocn) and bone sialoprotein (Bsp). In contrast, earlier differentiation events including alkaline phosphatase (ALP) activation and osteopontin (Opn) expression were not inhibited by JNK inactivation. Although the expression levels of two transcription factor genes, Runx2 and Osx, were not significantly affected by JNK inactivation, induction of Atf4 mRNA during osteoblast differentiation was significantly inhibited. Taken together, these data indicate that JNK activity is specifically required for the late-stage differentiation events of osteoblasts.
巻・号 24(3)
ページ 398-410
公開日 2009-3-1
DOI 10.1359/jbmr.081107
PMID 19016586
MeSH Activating Transcription Factor 4 / metabolism* Animals Bone Matrix / drug effects Bone Matrix / enzymology Calcification, Physiologic / drug effects Cell Differentiation* / drug effects Cell Line Clone Cells Core Binding Factor Alpha 1 Subunit / metabolism Gene Expression Regulation / drug effects Integrin-Binding Sialoprotein Isoenzymes / metabolism Mice Mice, Inbred C57BL Mitogen-Activated Protein Kinase 9 / antagonists & inhibitors Mitogen-Activated Protein Kinase 9 / metabolism* Osteoblasts / cytology* Osteoblasts / drug effects Osteoblasts / enzymology* Osteocalcin / genetics Osteocalcin / metabolism Phosphoric Monoester Hydrolases / metabolism Protein Kinase Inhibitors / pharmacology Sialoglycoproteins / genetics Sialoglycoproteins / metabolism Sp7 Transcription Factor Substrate Specificity / drug effects Transcription Factors / metabolism
IF 5.854
引用数 101
WOS 分野 ENDOCRINOLOGY & METABOLISM
リソース情報
ヒト・動物細胞 MC3T3-E1(RCB1126)