title: Lysyl oxidase and the lysyl oxidase-like protein modulate odontoblastic differentiation of human dental pulp cells.
abstract: BACKGROUND
  The lysyl oxidase (LOX) family is an emerging family of amine oxidases responsible for the formation of collagen fibrils in the extracellular matrix. To date, 5 LOX family genes have been identified in humans, encoding LOX and LOX-like proteins (LOXL, LOXL2, LOXL3, and LOXL4). The goal of this study was to evaluate the expression and function of the LOX family genes in odontoblastic differentiation of human dental pulp (HDP) cells.
  
  
  METHODS
  Expression of the LOX family genes was assessed by reverse transcriptase polymerase chain reaction analysis, and the amine oxidase activity of HDP cells was evaluated by peroxidase-coupled fluorometric assays. Mineral nodule formation and expression of odontoblastic marker genes were assessed in the presence and absence of specific small interfering RNAs (siRNAs) of the LOX family genes.
  
  
  RESULTS
  Among the LOX family genes, only LOX and LOXL showed prominent expression during odontoblastic differentiation of HDP cells. Suppression of LOX and LOXL expression by siRNA-induced interference substantially decreased the amine oxidase activity of the differentiating HDP cells. Furthermore, interference of LOX and LOXL expression inhibited mineral nodule formation and expression of odontoblastic marker genes during odontoblastic differentiation of HDP cells.
  
  
  CONCLUSIONS
  These findings show for the first time that the LOX- and LOXL-mediated organization of collagen fibrils in extracellular matrices of HDP cells might be an important regulator for odontoblastic differentiation of HDP cells.
authors.affiliation: Department of Maxillofacial Tissue Regeneration, School of Dentistry, Kyung Hee University, Seoul, South Korea.
authors.forename: Eun-Cheol
authors.initials: EC
authors.lastname: Kim
authors.forename: Hwa-Jeong
authors.initials: HJ
authors.lastname: Lee
authors.forename: Youngho
authors.initials: Y
authors.lastname: Kim
mesh_terms: D000469:Alkaline Phosphatase / Q000096:biosynthesis; D000594:Amino Acid Oxidoreductases / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D000704:Analysis of Variance; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics; D003782:Dental Pulp / Q000166:cytology* / Q000201:enzymology*; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis; D005470:Fluorometry; D006801:Humans; D009804:Odontoblasts / Q000201:enzymology*; D053244:Osteoprotegerin / Q000096:biosynthesis; D010750:Phosphoproteins / Q000096:biosynthesis; D061251:Primary Cell Culture; D008249:Protein-Lysine 6-Oxidase / Q000096:biosynthesis / Q000235:genetics*; D034622:RNA Interference; D034741:RNA, Small Interfering; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012795:Sialoglycoproteins / Q000096:biosynthesis; D018709:Statistics, Nonparametric; D014162:Transfection; D000099311:Dentin Sialophosphoprotein
chemical_list: D000469:Alkaline Phosphatase; D000594:Amino Acid Oxidoreductases; D002118:Calcium; D016326:Extracellular Matrix Proteins; D053244:Osteoprotegerin; D010750:Phosphoproteins; D008249:Protein-Lysine 6-Oxidase; D034741:RNA, Small Interfering; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein; C445313:LOXL1 protein, human