title: Insulin-like growth factor 1 promotes the proliferation and committed differentiation of human dental pulp stem cells through MAPK pathways.
abstract: OBJECTIVE
  Insulin-like growth factor 1 (IGF-1) is a broad-spectrum growth-promoting factor that plays a key role in natural tooth development. Human dental pulp stem cells (hDPSCs) are multipotent and can influence the reparative regeneration of dental pulp and dentin. This study was designed to evaluate the effects of IGF-1 on the proliferation and differentiation of human dental pulp stem cells.
  
  
  METHODS
  HDPSCs were isolated and purified from human dental pulps. The proliferation and osteo/odontogenic differentiation of hDPSCs treated with 100ng/ml exogenous IGF-1 were subsequently investigated.
  
  
  RESULTS
  MTT assays revealed that IGF-1 enhanced the proliferation of hDPSCs. ALP activity in IGF-1-treated group was obviously enhanced compared to the control group from days 3 to 9. Alizarin red staining revealed that the IGF-1-treated cells contained a greater number of mineralization nodules and had higher calcium concentrations. Moreover, western blot and qRT-PCR analyses demonstrated that the expression levels of several osteogenic genes (e.g., RUNX2, OSX, and OCN) and an odontoblast-specific marker (DSPP) were significantly up-regulated in IGF-1-treated hDPSCs as compared with untreated cells (P<0.01). Interestingly, the expression of phospho-ERK and phospho-p38 were also up-regulated, indicating that the MAPK signaling pathway is activated during the differentiation of hDPSCs.
  
  
  CONCLUSIONS
  IGF-1 can promote the proliferation and osteo/odontogenic differentiation of hDPSCs by activating MAPK pathways.
authors: Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu 210004, China.
authors: Taohong
authors: T
authors: Lv
authors: Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu 210004, China.
authors: Yongzheng
authors: Y
authors: Wu
authors: Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu 210004, China.
authors: Chao
authors: C
authors: Mu
authors: Institute of Stomatology, School of Stomatology, Nanjing Medical University, 136 Hanzhong Road, Nanjing, Jiangsu 210029, China.
authors: Genxia
authors: G
authors: Liu
authors: Endodontic Department, School of Stomatology, Nanjing Medical University, 136 Hanzhong Road, Nanjing, Jiangsu 210029, China.
authors: Ming
authors: M
authors: Yan
authors: Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu 210004, China.
authors: Xiangqin
authors: X
authors: Xu
authors: Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu 210004, China.
authors: Huayin
authors: H
authors: Wu
authors: Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu 210004, China.
authors: Jinyin
authors: J
authors: Du
authors: Endodontic Department, School of Stomatology, Nanjing Medical University, 136 Hanzhong Road, Nanjing, Jiangsu 210029, China; Institute of Stomatology, School of Stomatology, Nanjing Medical University, 136 Hanzhong Road, Nanjing, Jiangsu 210029, China. Electronic address: yujinhua@njmu.edu.cn.
authors: Jinhua
authors: J
authors: Yu
authors: Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu 210004, China. Electronic address: dentmjq@163.com.
authors: Jinquan
authors: J
authors: Mu
mesh_terms: D015153:Blotting, Western; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D003782:Dental Pulp / Q000166:cytology*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D009805:Odontogenesis / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D013234:Stem Cells / Q000187:drug effects*; D015854:Up-Regulation
chemical_list: D007334:Insulin-Like Growth Factor I
keywords: Dental pulp stem cells; Differentiation; Insulin-like growth factor 1; Odontogenesis; Osteogenesis; Proliferation