Matrix protein biglycan induces osteoblast differentiation through extracellular signal-regulated kinase and Smad pathways.
Biglycan (Bgn) is a member of the small leucine-rich proteoglycan (SLRP) family found in bone extracellular matrix (ECM), and hence involved in regulating bone formation and matrix mineralization. It has been reported that Bgn facilitates osteoblast differentiation, and extracellular signal-regulated kinase (Erk) and Smad are two important pathways in regulating osteoblast differentiation. However, the underlying mechanism for Bgn facilitating osteoblast differentiation has not been fully elucidated. The present study demonstrated that the matrix protein Bgn activates Erk signaling pathway and therefore increases Runx2 transcriptional activity, in which glycosaminoglycans (GAGs) chains play an essential role. Additionally, Bgn also activated Smad pathway, another signaling pathway related with osteoblast differentiation. The activation of these two signaling pathways induced by Bgn facilitated the mineralization deposition in vitro. These results demonstrated the mechanism of Bgn promoting osteoblast differentiation and matrix mineralization.
Protein Science Key Laboratory of the Ministry of Education, School of Medicine, Tsinghua University, Beijing 100084, PR China.
Xiaoyan
X
Wang
Kenichi
K
Harimoto
Sijia
S
Xie
Hao
H
Cheng
Jing
J
Liu
Zhao
Z
Wang
D016475:3T3 Cells; D000818:Animals; D058578:Biglycan / Q000378:metabolism*; D001857:Bone Matrix / Q000378:metabolism*; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism; D016466:CHO Cells; D002454:Cell Differentiation / Q000502:physiology*; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D006025:Glycosaminoglycans / Q000378:metabolism; D051379:Mice; D008903:Minerals / Q000378:metabolism*; D010006:Osteoblasts / Q000166:cytology*; D010012:Osteogenesis / Q000502:physiology; D015398:Signal Transduction; D051896:Smad Proteins, Receptor-Regulated / Q000378:metabolism*
D058578:Biglycan; D055396:Bone Morphogenetic Protein 2; D050659:Core Binding Factor Alpha 1 Subunit; D016326:Extracellular Matrix Proteins; D006025:Glycosaminoglycans; D008903:Minerals; C493716:Runx2 protein, mouse; D051896:Smad Proteins, Receptor-Regulated; D048049:Extracellular Signal-Regulated MAP Kinases