Deletion of RBPJK in Mesenchymal Stem Cells Enhances Osteogenic Activity by Up-Regulation of BMP Signaling.
Recently we have demonstrated the importance of RBPjk-dependent Notch signaling in the regulation of mesenchymal stem cell (MSC) differentiation during skeletogenesis both in vivo and in vitro. Here we further performed RBPJK loss-of-function experiments to demonstrate for the first time that RBPJK deficient MSC shows enhanced differentiation and osteogenesis acts via up-regulation of the BMP signaling. In the present study, we first compared the spontaneous and osteogenic differentiation in normal and recombination signal binding protein for immunoglobulin kappa J region (RBPJK) deficient human bone marrow-derived mesenchymal stem cells (MSCs). It was found that RBPJK highly expressed in fresh isolated MSCs and its expression was progressing down-regulated during spontaneous differentiation and even greater in osteogenic media inducted differentiation. Deletion of RBPJK in MSCs not only enhances cell spontaneous differentiation, but also significantly accelerates condition media inducted osteogenic differentiation by showing enhanced alkaline phosphatase (ALP) activity, Alizarin red staining, gene expression of Runx2, Osteopontin (OPN), Type I collagen (COL1a1) in culture. Additionally, BMP signaling responsive reporter activity and phosphor-smad1/5/8 expression were also significantly increased upon removal of RBPJK in MSCs. These data proved that inhibition of Notch signaling in MSCs promotes cell osteogenic differentiation by up-regulation of BMP signaling, and RBPJK deficient MSC maybe a better cell population for cell-based bone tissue engineering.
Department of Orthopaedic Surgery, Anhui Provincial Hospital, Hefei, Anhui, China.
Xifu
X
Shang
Department of Orthopaedic Surgery, Anhui Provincial Hospital, Hefei, Anhui, China.
Zhengliang
Z
Luo
Department of Oral and Craniomaxillofacial Surgery, Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
Xudong
X
Wang
Department of Orthopaedic Surgery, Louisiana State University Health Sciences Center, Shreveport, LA, United States of America.
Todd
T
Jaeblon
Department of Orthopaedic Surgery, Louisiana State University Health Sciences Center, Shreveport, LA, United States of America.
John V
JV
Marymont
Department of Orthopaedic Surgery, Louisiana State University Health Sciences Center, Shreveport, LA, United States of America.
Yufeng
Y
Dong
D000368:Aged; D017209:Apoptosis; D015153:Blotting, Western; D055395:Bone Morphogenetic Protein 1 / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D005260:Female; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D006801:Humans; D007124:Immunoenzyme Techniques; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein / Q000172:deficiency* / Q000235:genetics; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism*; D008875:Middle Aged; D010012:Osteogenesis / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; C497570:RBPJ protein, human; D012333:RNA, Messenger; C525705:BMP1 protein, human; D055395:Bone Morphogenetic Protein 1