COMP-Ang1, a chimeric form of Angiopoietin 1, enhances BMP2-induced osteoblast differentiation and bone formation
| Autor: | Hyun Joo Kim, Gou Young Koh, Kyung-Keun Kim, Kkot-Nim Lee, Byung-Chul Jeong, Sun-Hun Kim, Shee-Eun Lee, In-Ho Bae, Won-Mann Oh, In-Chol Kang, Jeong-Tae Koh, Kwang Youl Lee |
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| Rok vydání: | 2010 |
| Předmět: |
Male
Transcriptional Activation musculoskeletal diseases medicine.medical_specialty animal structures Histology Transcription Genetic Physiology Recombinant Fusion Proteins Endocrinology Diabetes and Metabolism Bone Morphogenetic Protein 2 Bone morphogenetic protein Bone morphogenetic protein 2 Cell Line Mice Calcification Physiologic Osteogenesis Internal medicine Angiopoietin-1 medicine Animals Humans Phosphorylation Protein kinase B Endochondral ossification PI3K/AKT/mTOR pathway Osteoblasts biology Cell Differentiation Osteoblast Receptor TIE-2 Angiopoietin receptor Extracellular Matrix Cell biology Mice Inbred C57BL medicine.anatomical_structure Endocrinology Gene Expression Regulation Osteocalcin biology.protein Signal Transduction |
| Zdroj: | Bone. 46:479-486 |
| ISSN: | 8756-3282 |
| DOI: | 10.1016/j.bone.2009.09.019 |
| Popis: | Introduction Angiogenesis is closely associated with bone formation, especially endochondral ossification. Angiopoietin 1 (Ang1) is a specific growth factor functioning to generate a stable and matured vasculature through the Tie2 receptor/PI3K/AKT pathway. Recently cartilage oligomeric matrix protein (COMP)-Ang1, an Ang1 variant which is more potent than native Ang1 in phosphorylating Tie2 receptor and AKT, was developed. This study was designed to examine the effects of angiogenic COMP-Ang1 on BMP2-induced osteoblast differentiation and bone formation. Methods Expression of endogenous Ang-1 and its binding receptor Tie 2 mRNA was examined in osteoblast-like cells and primary mouse calvarial cells by RT-PCR analysis, and was also monitored during osteoblast differentiation induced by BMP-2 and/or ascorbic acid and β-glycerophosphate. Effects of COMP-Ang-1 on osteoblast differentiation and mineralization were evaluated by alkaline phosphatase (ALP) activity and osteocalcin (OC) production, and Alizarin red stain. For a molecular mechanism, Western blot and OG2 and 6xOSE promoter assays were done. For in vivo evaluation, adenoviral (Ad) vectors containing COMP-Ang-1 or BMP-2 gene were administered into thigh muscle of mice, and after 2 weeks bone formation was analyzed by micro-computed tomography and histology. Angiogenic event of COMP-Ang1 was confirmed by immunofluorescence analysis with anti-CD31 antibody. Results Expression of Tie2 receptor was significantly increased in the course of osteoblast differentiation. Treatment or overexpression of COMP-Ang1 enhanced BMP2-induced ALP activity, OC production, and mineral deposition in a dose-dependent manner. In addition, COMP-Ang1 synergistically increased OG2 and 6xOSE promoter activities of BMP2, and sustained p38, Smad and AKT phosphorylation of BMP2. Notably, in vivo intramuscular injection of COMP-Ang1 dose-dependently enhanced BMP2-induced ectopic bone formation with increases in CD31 reactivity. Conclusions These results suggest that COMP-Ang1 synergistically enhanced osteoblast differentiation and bone formation through potentiating BMP2 signaling pathways and angiogenesis. Combination of BMP2 and COMP-Ang1 should be clinically useful for therapeutic application to fracture and destructive bone diseases. |
| Databáze: | OpenAIRE |
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