Connective tissue growth factor (CTGF) is regulated by Wnt and bone morphogenetic proteins signaling in osteoblast differentiation of mesenchymal stem cells.
Osteoblast lineage-specific differentiation of mesenchymal stem cells is a well regulated but poorly understood process. Both bone morphogenetic proteins (BMPs) and Wnt signaling are implicated in regulating osteoblast differentiation and bone formation. Here we analyzed the expression profiles of mesenchymal stem cells stimulated with Wnt3A and osteogenic BMPs, and we identified connective tissue growth factor (CTGF) as a potential target of Wnt and BMP signaling. We confirmed the microarray results, and we demonstrated that CTGF was up-regulated at the early stage of BMP-9 and Wnt3A stimulations and that Wnt3A-regulated CTGF expression was beta-catenin-dependent. RNA interference-mediated knockdown of CTGF expression significantly diminished BMP-9-induced, but not Wnt3A-induced, osteogenic differentiation, suggesting that Wnt3A may also regulate osteoblast differentiation in a CTGF-independent fashion. However, constitutive expression of CTGF was shown to inhibit both BMP-9- and Wnt3A-induced osteogenic differentiation. Exogenous expression of CTGF was shown to promote cell migration and recruitment of mesenchymal stem cells. Our findings demonstrate that CTGF is up-regulated by Wnt3A and BMP-9 at the early stage of osteogenic differentiation, which may regulate the proliferation and recruitment of osteoprogenitor cells; however, CTGF is down-regulated as the differentiation potential of committed pre-osteoblasts increases, strongly suggesting that tight regulation of CTGF expression may be essential for normal osteoblast differentiation of mesenchymal stem cells.
Luo
Qing
Q
Molecular Oncology Laboratory, Department of Surgery, the University of Chicago Medical Center, 5841 South Maryland Avenue, Chicago, IL 60637, USA.
Kang
Quan
Q
Si
Weike
W
Jiang
Wei
W
Park
Jong Kyung
JK
Peng
Ying
Y
Li
Xinmin
X
Luu
Hue H
HH
Luo
Jeffrey
J
Montag
Anthony G
AG
Haydon
Rex C
RC
He
Tong-Chuan
TC
D000256:Adenoviridae / Q000235:genetics; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D001842:Bone and Bones / Q000502:physiology; D002454:Cell Differentiation; D002460:Cell Line; D002465:Cell Movement; D055513:Connective Tissue Growth Factor; D003598:Cytoskeletal Proteins / Q000378:metabolism; D015536:Down-Regulation; D005786:Gene Expression Regulation; D049452:Green Fluorescent Proteins / Q000378:metabolism; D055427:Growth Differentiation Factor 2; D055412:Growth Differentiation Factors; D006801:Humans; D017874:Immediate-Early Proteins / Q000096:biosynthesis* / Q000235:genetics*; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism*; D008648:Mesoderm / Q000378:metabolism*; D051379:Mice; D008809:Mice, Inbred C3H; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D020411:Oligonucleotide Array Sequence Analysis; D010006:Osteoblasts / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D012313:RNA / Q000737:chemistry / Q000378:metabolism; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013234:Stem Cells; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism; D015854:Up-Regulation; D051153:Wnt Proteins; D060508:Wnt3 Protein; D060509:Wnt3A Protein; D051176:beta Catenin
D019485:Bone Morphogenetic Proteins; C526317:CCN2 protein, human; C526318:CCN2 protein, mouse; C495270:CTNNB1 protein, human; C495267:CTNNB1 protein, mouse; D003598:Cytoskeletal Proteins; C525887:GDF2 protein, human; C526108:Gdf2 protein, mouse; D055427:Growth Differentiation Factor 2; D055412:Growth Differentiation Factors; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins; D015534:Trans-Activators; C555510:WNT3A protein, human; D051153:Wnt Proteins; D060508:Wnt3 Protein; D060509:Wnt3A Protein; C555511:Wnt3a protein, mouse; D051176:beta Catenin; D055513:Connective Tissue Growth Factor; D049452:Green Fluorescent Proteins; D012313:RNA; D000469:Alkaline Phosphatase