SPARC stimulates the synthesis of OPG/OCIF, MMP-2 and DNA in human periodontal ligament cells.
BACKGROUND
Osteonectin/secreted protein, acidic and rich in cysteine (SPARC) is expressed in periodontal ligaments. Therefore, a better understanding of the action of SPARC on periodontal ligament cells could help to elucidate remodelling and repair mechanisms in periodontal tissue. In the present study, we examined the effects of human platelet-derived SPARC (hp-SPARC) on the expressions of SPARC and osteoprotegerin/osteoclastogenesis inhibitory factor (OPG/OCIF), alkaline phosphatase (ALPase) activity, matrix metalloproteinase-2 (MMP-2) production and DNA synthesis in cultures of human periodontal ligament (HPL) cells.


METHODS
HPL cells at the sixth passage were exposed to hp-SPARC. The expression of OPG/OCIF and SPARC mRNAs was examined by Northern blot analysis. The protein levels for OPG/OCIF and MMP-2 were determined by Western blot analysis. ALPase activity was measured by the method of Bessey et al. DNA synthesis was estimated by incorporation of [3H] thymidine.


RESULTS
Hp-SPARC enhanced OPG/OCIF synthesis at the protein and mRNA levels. Hp-SPARC also enhanced DNA and MMP-2 synthesis dose-dependently, but had little effect on ALPase activity and SPARC mRNA expression.


CONCLUSIONS
SPARC may play a role in remodelling and repair of periodontal tissue by promoting proliferation and MMP-2 production. It may also regulate osteoclast formation through OPG/OCIF in periodontal ligament cells.
Department of Periodontal Medicine, Division of Frontier Medical Science, Hiroshima University Graduate School of Biomedical Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan.
Tsuyoshi
T
Fujita
Hideki
H
Shiba
Masatoshi
M
Sakata
Yuushi
Y
Uchida
Shigeo
S
Nakamura
Hidemi
H
Kurihara
D000469:Alkaline Phosphatase / Q000378:metabolism; D000704:Analysis of Variance; D015152:Blotting, Northern; D015153:Blotting, Western; D016723:Bone Remodeling; D002452:Cell Count; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D006023:Glycoproteins / Q000096:biosynthesis; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis; D015676:Osteonectin / Q000378:metabolism*; D053244:Osteoprotegerin; D010513:Periodontal Ligament / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D018160:Receptors, Cytoplasmic and Nuclear / Q000096:biosynthesis; D018124:Receptors, Tumor Necrosis Factor; D012038:Regeneration
D006023:Glycoproteins; D015676:Osteonectin; D053244:Osteoprotegerin; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D018124:Receptors, Tumor Necrosis Factor; C506030:TNFRSF11B protein, human; D004247:DNA; D000469:Alkaline Phosphatase; D020778:Matrix Metalloproteinase 2