title: The parathyroid hormone-related protein is secreted during the osteogenic differentiation of human dental follicle cells and inhibits the alkaline phosphatase activity and the expression of DLX3.
abstract: The dental follicle is involved in tooth eruption and it expresses a great amount of the parathyroid hormone-related protein (PTHrP). PTHrP as an extracellular protein is required for a multitude of different regulations of enchondral bone development and differentiation of bone precursor cells and of the development of craniofacial tissues. The dental follicle contains also precursor cells (DFCs) of the periodontium. Isolated DFCs differentiate into periodontal ligament cells, alveolar osteoblast and cementoblasts. However, the role of PTHrP during the human periodontal development remains elusive. Our study evaluated the influence of PTHrP on the osteogenic differentiation of DFCs under in vitro conditions for the first time. The PTHrP protein was highly secreted after 4days of the induction of the osteogenic differentiation of DFCs with dexamethasone (2160.5pg/ml±345.7SD. in osteogenic differentiation medium vs. 315.7pg/ml±156.2SD. in standard cell culture medium; Student's t Test: p<0.05 (n=3)). We showed that the supplementation of the osteogenic differentiation medium with PTHrP inhibited the alkaline phosphatase activity and the expression of the transcription factor DLX3, but the depletion of PTHrP did not support the differentiation of DFCs. Previous studies have shown that Indian Hedgehog (IHH) induces PTHrP and that PTHrP, in turn, inhibits IHH via a negative feedback loop. We showed that SUFU (Suppressor Of Fused Homolog) was not regulated during the osteogenic differentiation in DFCs. So, neither the hedgehog signaling pathway induced PTHrP nor PTHrP suppressed the hedgehog signaling pathway during the osteogenic differentiation in DFCs. In conclusion, our results suggest that PTHrP regulates independently of the hedgehog signaling pathway the osteogenic differentiated in DFCs.
authors.affiliation: Department of Cranio- and Maxillofacial Surgery, Hospital of the University of Regensburg, Regensburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Klingelhöffer
authors.affiliation: Department of Cranio- and Maxillofacial Surgery, Hospital of the University of Regensburg, Regensburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Reck
authors.affiliation: Department of Cranio- and Maxillofacial Surgery, Hospital of the University of Regensburg, Regensburg, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Ettl
authors.affiliation: Department of Cranio- and Maxillofacial Surgery, Hospital of the University of Regensburg, Regensburg, Germany. Electronic address: christian.morsczeck@ukr.de.
authors.forename: C
authors.initials: C
authors.lastname: Morsczeck
mesh_terms: D000469:Alkaline Phosphatase / Q000096:biosynthesis; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000235:genetics*; D003795:Dental Sac / Q000187:drug effects / Q000254:growth & development; D003907:Dexamethasone / Q000008:administration & dosage; D053823:Hedgehog Proteins / Q000235:genetics; D018398:Homeodomain Proteins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D010012:Osteogenesis / Q000235:genetics*; D044162:Parathyroid Hormone-Related Protein / Q000037:antagonists & inhibitors / Q000235:genetics*; D010519:Periodontium / Q000187:drug effects / Q000254:growth & development; D012097:Repressor Proteins / Q000096:biosynthesis* / Q000235:genetics; D015398:Signal Transduction; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics
chemical_list: C088334:Distal-less homeobox proteins; D053823:Hedgehog Proteins; D018398:Homeodomain Proteins; D044162:Parathyroid Hormone-Related Protein; D012097:Repressor Proteins; C490764:SUFU protein, human; D014157:Transcription Factors; D003907:Dexamethasone; D000469:Alkaline Phosphatase
keywords: Dental follicle cells; Osteogenic differentiation; Parathyroid hormone-related protein; Periodontal development