Smad 1/5 Is Involved in Bone Morphogenetic Protein-2–induced Odontoblastic Differentiation in Human Dental Pulp Cells

• Published in: Journal of endodontics Vol. 38; no. 1; pp. 66 - 71
• Main Authors: Qin, Wei, PhD, Yang, Fen, PhD, Deng, Rong, PhD, Li, Dandan, PhD, Song, Zhi, PhD, Tian, Yaguang, PhD, Wang, Runfu, PhD, Ling, Junqi, PhD, Lin, Zhengmei, PhD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 2012
• Subjects: Alkaline Phosphatase - analysis; Alkaline Phosphatase - drug effects; Biomarkers - analysis; Blotting, Western; Bone morphogenetic protein; Bone Morphogenetic Protein 2 - antagonists & inhibitors; Bone Morphogenetic Protein 2 - pharmacology; Bone Morphogenetic Proteins - antagonists & inhibitors; Calcification, Physiologic - drug effects; Carrier Proteins - pharmacology; Cell Culture Techniques; Cell Differentiation - drug effects; Cell Nucleus - metabolism; Dental Pulp - cytology; Dental Pulp - drug effects; Dentistry; Endocrinology & Metabolism; Fluorescent Antibody Technique, Indirect; Humans; mineralization; odontoblast; Odontoblasts - drug effects; Phosphorylation; Protein Transport; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction - drug effects; Smad proteins; Smad1 Protein - metabolism; Smad1 Protein - pharmacology; Smad5 Protein - metabolism; Smad5 Protein - pharmacology; Smad proteins; mineralization; odontoblast; Bone morphogenetic protein
• ISSN: 0099-2399; 1878-3554
• DOI: 10.1016/j.joen.2011.09.025

Abstract Introduction Bone morphogenetic protein-2 (BMP-2) is a member of the transforming growth factor-β (TGF-β) superfamily, which has a broad range of activities that affect many different cell types. Previous research has suggested that BMP-2 induces the differentiation of human dental pulp cells (DPCs) into odontoblast-like cells. However, the mechanism by which BMP-2 induces odontoblastic differentiation has not yet been established. In the present study, we examined the involvement of the BMP/Smad pathway in mediating odontoblastic differentiation in DPCs. Methods Levels of phosphorylated and unphosphorylated Smad1/5 were quantified by Western blot analysis in response to BMP-2 and the BMP signaling inhibitor noggin. Some nuclear translocation of Smad1/5 was also observed by immunofluorescence staining in isolated DPCs treated with BMP-2. The effects of noggin on the BMP-2–induced odontoblastic differentiation of DPCs were determined by alkaline phosphatase activity assay, and the expression of odontoblastic markers was evaluated by reverse transcription polymerase chain reaction analysis and Western blotting. Results We found that BMP-2 induced the phosphorylation and nuclear translocation of Smad 1/5. In addition, noggin significantly inhibited alkaline phosphatase activity and odontoblastic differentiation and reduced the formation of mineralized nodules in BMP-2–treated DPCs. Conclusions These findings suggest that Smad 1/5 is involved in BMP-2–induced odontoblastic differentiation in DPCs.