Bone morphogenetic protein 2 induces cyclo-oxygenase 2 in osteoblasts via a Cbfa1 binding site: Role in effects of bone morphogenetic protein 2 in vitro and in vivo
Bone morphogenetic protein 2 induces cyclo-oxygenase 2 in osteoblasts via a Cbfa1 binding site: Role in effects of bone morphogenetic protein 2 in vitro and in vivo
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DOI：
10.1359/jbmr.2002.17.8.1430
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发表时间：
2002-08-01
影响因子：
6.2
通讯作者：
Pilbeam, CC
中科院分区：
文献类型：
--
作者：
Chikazu, D;Li, XD;Pilbeam, CC
我们验证了环氧合酶(COX)2的诱导介导骨形态发生蛋白(BMP)2对骨的某些作用的假说。BMP-2可诱导成骨细胞COX-2mRNA和前列腺素(PG)的产生。BMP-2增加了转COX-2启动子-荧光素酶报告结构(PLUC)的小鼠颅骨成骨细胞和转染PLUC的MC3T3-E1细胞中的荧光素酶活性。缺失分析表明，COX-2启动子的-300/-213-BP区域是BMP-2刺激荧光素酶活性所必需的。核心结合因子活性I(MuCbfa1)共有序列(5‘-AACCACA-3’)-267/-261bp的突变使BMP-2对荧光素酶活性的刺激减少了82%。核蛋白与跨越MAL位点的寡核苷酸的结合被Cbfa1的特异性抗体抑制或超移。在COX-2基因敲除(-/-)和野生型(+/+)小鼠培养的成骨细胞中，COX-2表达的缺失降低了BMP-2对ALP活性和骨钙素mRNA表达的刺激。在培养的长骨骨髓细胞中，BMP-2诱导COX-2(+/+)小鼠的破骨细胞形成，但不诱导COX-2(-/-)小鼠的破骨细胞形成。在体内，BMP-2(10杯/粒)诱导植入小鼠侧翼的冻干胶原粒矿化。COX-2(-/-)小鼠与COX-2(+/+)小鼠相比，微计算机断层扫描(MUCT)测得的颗粒矿化程度降低了78%。结论：BMP-2通过Cbfa1结合位点在转录水平上诱导成骨细胞中COX-2的表达，BMP-2对COX-2的诱导作用可能与BMP-2在体外对成骨细胞分化和破骨细胞形成的影响以及BMP-2对体内异位骨形成的刺激作用有关。
We tested the hypothesis that induction of cyclo-oxygenase (COX) 2 mediates some effects of bone morphogenetic protein (BMP) 2 on bone. BMP-2 induced COX-2 mRNA and prostaglandin (PG) production in cultured osteoblasts. BMP-2 increased luciferase activity in calvarial osteoblasts from mice transgenic for a COX-2 promoter-luciferase reporter construct (Pluc) and in MC3T3-E1 cells transfected with Pluc. Deletion analysis identified the -300/-213-bp region of the COX-2 promoter as necessary for BMP-2 stimulation of luciferase activity. Mutation of core-binding factor activity I (muCbfa1) consensus sequence (5'-AACCACA-3') at -267/-261 bp decreased BMP-2 stimulation of luciferase activity by 82%. Binding of nuclear proteins to an oligonucleotide spanning the Mal site was inhibited or supershifted by specific antibodies to Cbfa1. In cultured osteoblasts from colvariae of COX-2 knockout (-/-) and wild-type (+/+) mice, the absence of COX-2 expression reduced the BMP-2 stimulation of both ALP activity and osteocalcin mRNA expression. In cultured marrow cells Hushed from long bones, BMP-2 induced osteoclast formation in cells from COX-2(+/+) mice but not in cells from COX-2(-/-) mice. In vivo, BMP-2 (10 mug/pellet) induced mineralization in pellets of lyophilized collagen implanted in the flanks of mice. Mineralization of pellets, measured by microcomputed tomography (muCT), was decreased by 78% in COX-2(-/-) mice compared with COX-2(+/+) mice. We conclude that BMP-2 transcriptionally induces COX-2 in osteoblasts via a Cbfa1 binding site and that the BMP-2 induction of COX-2 can contribute to effects of BMP-2 on osteoblastic differentiation and osteoclast formation in vitro and to the BMP-2 stimulation of ectopic bone formation in vivo.