Functional requirement of CCN2 for intramembranous bone formation in embryonic mice

Abstract

CCN2 is best known as a promoter of chondrocyte differentiation among the CCN family members, and Ccn2 null mutant mice display skeletal dysmorphisms. However, little is known concerning the roles of CCN2 during bone formation. We herein present a comparative analysis of wild-type and Ccn2 null mice to investigate the roles of CCN2 in bone development. Multiple histochemical methods were employed to analyze the effects of CCN2 deletion in vivo, and effects of CCN2 on the osteogenic response were evaluated with the isolated and cultured osteoblasts. As a result, we found a drastic reduction of the osteoblastic phenotype in Ccn2 null mutants. Importantly, addition of exogenous CCN2 promoted every step of osteoblast differentiation and rescued the attenuated activities of the Ccn2 null osteoblasts. These results suggest that CCN2 is required not only for the regulation of cartilage and subsequent events, but also for the normal intramembranous bone development.

Osteogenic differentiation of mesenchymal stem cells promoted by overexpression of connective tissue growth factor

“…Similarly to our results, CTGF had been proved to enhance the differentiation and function of osteoblast-like Saos-2 cells, MC3T3-E1 cells, and primary osteoblast cultures (Nishida et al, 2000;Abreu et al, 2002;Ivkovic et al, 2003;Safadi et al, 2003;Kawaki et al, 2008;Ono et al, 2008). In contrast, CTGF overexpression did not promote osteoblastic differentiation or mineralization in fibroblasts NIH3T3 cell line.…”

Connective Tissue Growth Factor Enhances Osteoblastogenesis in Vitro

“…Transduction of C3H10T 1 ⁄ 2 mesenchymal cells with adenoviral vectors for the constitutive expression of CTGF or addition of CTGF to these cells results in impaired osteoblastogenesis (10,16). In contrast, addition of CTGF was shown to promote the differentiation and function of osteoblast-like Saos-2 cells, MC3T3-E1 cells, and primary osteoblast cultures (13)(14)(15)(16). In the present work, we have used a retroviral vector to deliver CTGF, which was expressed under the control of the CMV promoter, so that cells were continuously exposed to CTGF over a prolonged period of time.…”

“…These observations suggest that CTGF is required for normal osteoblastic function, but its role under conditions of CTGF induction is less clear. Exposure of ctgf null osteoblastic cells to CTGF protein enhances osteoblastic function, whereas the addition of CTGF protein to cultures has been reported both to favor and oppose osteoblastic function in wild type cells (13)(14)(15)(16).…”

“…The function of CTGF in skeletal cells is not well understood, and in vitro studies on the effects of CTGF in these cells have yielded controversial results. Experiments conducted in ctgf null calvarial osteoblasts or in C3H10T 1 ⁄ 2 cells following the down-regulation of CTGF using RNA interference (RNAi) have demonstrated that CTGF is necessary for osteoblastogenesis (10,13). Transduction of C3H10T 1 ⁄ 2 cells with adenoviral vectors for the constitutive expression of CTGF results in impaired osteoblastogenesis (10).…”

CCN3-mediated promotion of sulfated proteoglycan synthesis in rat chondrocytes from developing joint heads

“…Quantitative real-time PCR was performed as described previously (Yanagita et al 2007;Kawaki et al 2008a). Amplification was carried out with the cDNA templates obtained from the reverse transcription reaction by using the specific primers listed in Table 1 and an SYBR® Green Real Time PCR Master Mix (Toyobo, Osaka, Japan).…”