title: Periostin is a collagen associated bone matrix protein regulated by parathyroid hormone.
abstract: Periostin is a 90 kDa secreted protein, originally identified in murine osteoblast-like cells, with a distribution restricted to collagen-rich tissues and certain tumors. In this paper, we first analyzed the expression of periostin mRNA and protein in human fetal osteoblasts (hFOB) and human osteosarcoma (hOS) cell lines by RT real-time PCR and Western blot, respectively. The hFOB 1.19 and three hOS (MHM, KPDXM and Eggen) showed highly variable periostin mRNA levels and protein. Second, we showed that the expression of periostin mRNA was inversely related to the cells' abilities to differentiate and mineralize. Then, we investigated the regulation of periostin mRNA in hFOB after siRNA treatment and in mouse primary osteoblasts (mOB) treated with PTH. Knock-down of periostin mRNA, down-regulated PTHrP, but did not affect the expression of other important markers of differentiation such as RUNX2. In addition, periostin mRNA was transiently up-regulated in osteoblasts by PTH. Finally, the localization of periostin and its partially co-localization with collagen 1a1 mRNA and protein was studied in mouse embryos and postnatal pups using in situ hybridization and immunohistochemistry, respectively. In conclusion, the present study provides novel observations related to the expression, distribution and regulation of periostin in bone cells and extracellular matrix.
authors.affiliation: Department of Biochemistry, Institute of Basic Medical Sciences, PO Box 1112 Blindern, University of Oslo, N-0317 Oslo, Norway.
authors.forename: Dario
authors.initials: D
authors.lastname: Fortunati
authors.forename: Sjur
authors.initials: S
authors.lastname: Reppe
authors.forename: Ase-Karine
authors.initials: AK
authors.lastname: Fjeldheim
authors.forename: Marit
authors.initials: M
authors.lastname: Nielsen
authors.forename: Vigdis T
authors.initials: VT
authors.lastname: Gautvik
authors.forename: Kaare M
authors.initials: KM
authors.lastname: Gautvik
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001857:Bone Matrix / Q000378:metabolism*; D002113:Calcification, Physiologic / Q000235:genetics; D002356:Cartilage / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism*; D000090602:Collagen Type I, alpha 1 Chain; D050657:Core Binding Factor alpha Subunits / Q000235:genetics; D015536:Down-Regulation / Q000235:genetics; D004622:Embryo, Mammalian / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D015870:Gene Expression / Q000187:drug effects / Q000235:genetics; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism; D012516:Osteosarcoma; D010281:Parathyroid Hormone / Q000494:pharmacology*; D044162:Parathyroid Hormone-Related Protein / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
chemical_list: D015815:Cell Adhesion Molecules; D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D050657:Core Binding Factor alpha Subunits; C512835:POSTN protein, human; D010281:Parathyroid Hormone; D044162:Parathyroid Hormone-Related Protein; C082838:Postn protein, mouse; D034741:RNA, Small Interfering; D000469:Alkaline Phosphatase