Prostanoid- and interleukin-1-induced primary genes in cementoblastic cells.
BACKGROUND
Cementum is a key component of a functional periodontal organ. However, regenerating lost cementum is difficult and often incomplete. Identifying molecular mediators of cementoblast differentiation and function should lead to better targeted treatment for periodontitis. Prostaglandins increase mineralization of murine cementoblastic OCCM cells and alveolar bone formation, whereas the cytokine interleukin-1 (IL-1) inhibits alveolar bone formation. We hypothesized that differentially induced primary genes in OCCM cells may mediate anabolic and catabolic responses. Our objective was to identify primary genes differentially induced by the synthetic prostanoid fluprostenol and IL-1 in cementoblastic cells.


METHODS
Confluent OCCM cells were pretreated with the protein synthesis inhibitor cycloheximide followed by fluprostenol or IL-1 for 1.5 hours. cDNA generated from each group was used for cDNA subtraction hybridization to identify differentially induced genes. Preferential gene induction was verified by Northern blot analysis.


RESULTS
Thirteen fluprostenol- and seven IL-1-regulated genes were identified. Among the fluprostenol-induced genes was mitogen-activated protein (MAP) kinase phosphatase 1 (MKP1), a negative regulator of MAP kinase signaling. To verify the cDNA subtraction hybridization results, OCCM cells were treated with fluprostenol or prostaglandin F2 (PGF2), and MKP1 mRNA levels were determined. The 0.001 to 1 microM fluprostenol and 0.01 to 1 microM PGF2 significantly induced MKP1 mRNA levels, which peaked at 1 hour of treatment and returned to baseline at 2 hours.


CONCLUSIONS
Fluprostenol enhanced, whereas IL-1 inhibited, OCCM mineralization. Using cDNA subtraction hybridization, we identified primary genes that correlate with the observed anabolic and catabolic responses. These findings further our understanding of cementoblast function and suggest that differentially induced genes may mediate cementum formation and resorption.
Nervina
Jeanne M
JM
Section of Orthodontics, School of Dentistry, University of California, Los Angeles, CA 90095-1668, USA.
Camargo
Paulo M
PM
Bezouglaia
Olga
O
Tetradis
Sotirios
S
D000818:Animals; D015152:Blotting, Northern; D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000235:genetics*; D002461:Cell Line, Transformed; D018076:DNA, Complementary / Q000032:analysis; D003739:Dental Cementum / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D015237:Dinoprost / Q000494:pharmacology; D054638:Dual Specificity Phosphatase 1; D004790:Enzyme Induction; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects*; D017874:Immediate-Early Proteins / Q000096:biosynthesis / Q000235:genetics*; D007375:Interleukin-1 / Q000494:pharmacology*; D051379:Mice; D009693:Nucleic Acid Hybridization; D010749:Phosphoprotein Phosphatases / Q000096:biosynthesis / Q000235:genetics*; D011461:Prostaglandins F, Synthetic / Q000494:pharmacology*; D054645:Protein Phosphatase 1; D017027:Protein Tyrosine Phosphatases / Q000096:biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D014074:Tooth Calcification / Q000235:genetics*; D015533:Transcriptional Activation
D018797:Cell Cycle Proteins; D018076:DNA, Complementary; D017874:Immediate-Early Proteins; D007375:Interleukin-1; D011461:Prostaglandins F, Synthetic; D012333:RNA, Messenger; C006326:fluprostenol; D015237:Dinoprost; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D054638:Dual Specificity Phosphatase 1; C517020:Dusp1 protein, mouse; D017027:Protein Tyrosine Phosphatases