Osteoblast-Related Gene Expression of Bone Marrow Cells during the Osteoblastic Differentiation Induced by Type I Collagen

Abstract

Bone marrow contains multipotent cells that differentiate into fibroblasts, adipocytes, and osteoblasts. Recently we found that type I collagen matrix induced the osteoblastic differentiation of bone marrow cells. Three weeks after cells were cultured with type I collagen, they formed mineralized tissues. In this study, we investigated the expression of osteoblast-related genes (alkaline phosphatase, osteocalcin, bone sialoprotein, osteopontin, and cbfa-1) during the osteoblastic differentiation. The expression of alkaline phosphatase and osteopontin genes increased time-dependently during the osteoblastic differentiation. Osteocalcin and bone sialoprotein genes were expressed in cells that formed mineralized tissues, and both were expressed only after cells reached the mineralized tissue-formation stage. On the other hand, the cbfa-1 gene was expressed from the early differentiation stage. The Asp-Gly-Glu-Ala (DGEA) amino acid domain of type I collagen interacts with the alpha2beta1 integrin receptor on the cell membrane and mediates extracellular signals into cells. When the collagen-integrin interaction was interrupted by the addition of DGEA peptide to the culture, the expression of osteoblastic phenotypes of bone marrow cells was inhibited. These findings imply that the collagen-alpha2beta1 integrin interaction is an important signal for the osteoblastic differentiation of bone marrow cells.

Stimulation of Ectopic Bone Formation in Response to BMP-2 by Rho Kinase Inhibitor: A Pilot Study

“…Cbfa-1 is a crucial regulator for osteoblastic differentiation; however, the cbfa-1 gene expression during the osteoblastic differentiation is reportedly crucial in some cases and also celltype specific [5,14]. Consistent with our results, most recently Mizuno and Kuboki [21] reported that the cbfa-1 gene expression was independent for the osteoblastic differentiation lineage using rat bone marrow stromal cells cultured with Type I collagen. Other posttranslational mechanisms, such as phosphorylation or complex formation of the cbfa-1 protein, should be considered for the activity of this transcriptional factor.…”

A comparison of osteogenesis-related gene expression of mesenchymal stem cells during the osteoblastic differentiation induced by Type-I collagen and/or fibronectin

“…Next, we investigated the expression of the BMP-2 and cbfa-1 genes, and found their expression in MSCs cultured with type I collagen and/or fibronectin, respectively, after 6 days and 12 days. Cbfa-1 has been identified as an essential factor for osteoblastic differentiation, and bone has been shown to disappear in cbfa-1-knockout mice (18,28). Mizuno et al showed that the message level of cbfa-1 did not change in bone marrow cells cultured with type I collagen (18).…”

“…The biological significance of the proliferation/ differentiation relationship is also necessary for an understanding of the manner in which perturbations in specific genes may be related to a broad spectrum of skeletal disorders (15)(16)(17)(18). Gene expression inducement is associated with ECM maturation and mineralization.…”

Focal adhesion kinase signaling pathways regulate the osteogenic differentiation of human mesenchymal stem cells

“…Cell contact with extracellular matrix (ECM) proteins plays a critical role in regulating hMSC osteogenesis [3,[9][10][11]. Specifically, this interaction triggers osteoblast-specific expression of alkaline phosphatase and osteocalcin mRNAs, and ultimately, mineralization of bone tissue in a stage-specific sequence [12,13].…”

“…Specifically, this interaction triggers osteoblast-specific expression of alkaline phosphatase and osteocalcin mRNAs, and ultimately, mineralization of bone tissue in a stage-specific sequence [12,13]. Matrix responsiveness during osteogenesis is caused by the aggregation of the α2β1 [9,[14][15][16] and αvβ3 [17] integrins that subsequently activate intracellular signaling cascades, resulting in the phosphorylation of the osteoblast-specific transcription factor Runx2/Cbfa-1 [15,18,19]. Understanding the molecular signaling mechanisms associated with these events and the osteogenic differentiation of hMSC as a whole, will accelerate the practical application of stem cell engineering.…”