title: Nel-like Molecule 1 Contributes to the Odontoblastic Differentiation of Human Dental Pulp Cells.
abstract: BACKGROUND
  Nel-like molecule-1 (Nell-1) with epidermal cell growth factor-like coding structures is a recently discovered secreted protein that can specifically induce osteoblast differentiation, bone formation, and bone regeneration. The expression and localization of Nell-1 during murine molar development suggest that this protein participates in odontoblastic differentiation. This study aims to assess the expression of Nell-1 in the pulp-dentin complex of human teeth and determine the effect of human recombinant Nell-1 (hrNell-1) on odontoblastic differentiation of cultured human dental pulp cells.
  
  
  METHODS
  Immunohistochemical assay was performed to detect the expression and location of Nell-1 in healthy human teeth. The activity of alkaline phosphatase in human dental pulp cells stimulated by hrNell-1 was examined. Moreover, the expression of related odontoblastic markers was evaluated using quantitative real-time polymerase chain reaction and Western blot.
  
  
  RESULTS
  Immunohistochemical results showed that Nell-1 was primarily expressed in the odontoblasts (odontoblastic bodies and processes), pulp fibroblasts, and endothelial cells of the blood vessels in human teeth. In vitro experiments showed that hrNell-1 could increase the activity of alkaline phosphatase and enhance the expression of important odontoblastic markers including osteopontin and dentin matrix protein 1 in cultured human dental pulp cells.
  
  
  CONCLUSIONS
  Nell-1 plays a role in odontoblastic differentiation of human dental pulp cells and dentin formation.
authors.affiliation: Shandong Provincial Key Laboratory of Oral Biomedicine, School and Hospital of Stomatology, Shandong University, Jinan, Shandong, China.
authors.forename: Mengmeng
authors.initials: M
authors.lastname: Liu
authors.affiliation: Jinan Stomatological Hospital, Jinan, Shandong, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Shandong Provincial Key Laboratory of Oral Biomedicine, School and Hospital of Stomatology, Shandong University, Jinan, Shandong, China.
authors.forename: Ronghua
authors.initials: R
authors.lastname: Tang
authors.affiliation: Shandong Provincial Key Laboratory of Oral Biomedicine, School and Hospital of Stomatology, Shandong University, Jinan, Shandong, China.
authors.forename: Rongyu
authors.initials: R
authors.lastname: Cao
authors.affiliation: Shandong Provincial Key Laboratory of Oral Biomedicine, School and Hospital of Stomatology, Shandong University, Jinan, Shandong, China. Electronic address: wangxy.group@hotmail.com.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Wang
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D002135:Calcium-Binding Proteins; D002454:Cell Differentiation; D002478:Cells, Cultured; D003782:Dental Pulp / Q000166:cytology*; D003804:Dentin / Q000166:cytology*; D006801:Humans; D009419:Nerve Tissue Proteins / Q000502:physiology*; D009804:Odontoblasts / Q000502:physiology*
chemical_list: D002135:Calcium-Binding Proteins; C104144:NELL1 protein, human; D009419:Nerve Tissue Proteins; D000469:Alkaline Phosphatase
keywords: Human dental pulp cell; Nel-like molecule-1; odontoblastic differentiation; pulp-dentin complex