title: [Effects of muramyl dipeptide on the differentiation of human dental pulp cells].
abstract: OBJECTIVE
  To investigate the nucleotide-binding oligomerization domain-2 (NOD-2) gene expression in deep caries and the effects of NOD-2 agonist muramyl dipeptide (MDP) on the differentiation of human dental pulp cells (hDPC).
  
  
  METHODS
  NOD-2 gene level in deep caries and healthy pulp tissue was determined by real-time quantitative polymerase chain reaction (realtime-PCR). Realtime-PCR, Western blotting and immunofluorescence were performed to evaluate NOD-2 gene and protein expression. Dentin sialoprotein (DSP) protein level was assessed when hDPC were challenged by different concentrations of MDP for 24 hours, and sialophosphoprotein (DSPP), osteocalcin (OCN) mRNA and osteopontin (OPN) protein level were detected at different time points after incubation with 0.1 mg/L MDP.
  
  
  RESULTS
  NOD-2 mRNA level was higher in pulp tissue of deep caries (0.2610 ± 0.0824) than that in healthy controls (0.0024 ± 0.0002), P < 0.05. The expression of NOD-2 gene and protein increased in a time denpendent manner upon stimulation with MDP. Immunofluorescence confirmed that NOD-2 protein was located in cytoplasm. Moreover, 0.1 mg/L MDP augmented DSP protein level. DSPP and OCN mRNA were elevated with time and reached the peak at 12 h and down-regulated. OPN protein level also increased with time.
  
  
  CONCLUSIONS
  Dental pulp NOD-2 expression are up-regulated in pulp tissue of deep caries. MDP may be related to the differentiation of hDPC.
authors: Department of Operative Dentistry and Endodontics, Sun Yat-sen University, Guangzhou, China.
authors: Chuan-xia
authors: CX
authors: Luo
authors: Li
authors: L
authors: Zhang
authors: Zhi
authors: Z
authors: Song
authors: Wei
authors: W
authors: Qin
authors: Zheng-mei
authors: ZM
authors: Lin
mesh_terms: D000119:Acetylmuramyl-Alanyl-Isoglutamine / Q000494:pharmacology*; D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000293:Adolescent; D000328:Adult; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D003731:Dental Caries / Q000473:pathology*; D003782:Dental Pulp / Q000166:cytology* / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D053473:Nod2 Signaling Adaptor Protein / Q000235:genetics / Q000378:metabolism*; D015675:Osteocalcin / Q000235:genetics / Q000378:metabolism; D053495:Osteopontin / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012795:Sialoglycoproteins / Q000235:genetics / Q000378:metabolism; D055815:Young Adult; D000099311:Dentin Sialophosphoprotein
chemical_list: D000119:Acetylmuramyl-Alanyl-Isoglutamine; D000276:Adjuvants, Immunologic; D016326:Extracellular Matrix Proteins; D053473:Nod2 Signaling Adaptor Protein; D015675:Osteocalcin; D053495:Osteopontin; D010750:Phosphoproteins; D012333:RNA, Messenger; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein; C429018:NOD2 protein, human; C506895:SPP1 protein, human