Regulation of matrix Gla protein by parathyroid hormone in MC3T3-E1 osteoblast-like cells involves protein kinase A and extracellular signal-regulated kinase pathways.
Regulation of matrix Gla protein by parathyroid hormone in MC3T3-E1 osteoblast-like cells involves protein kinase A and extracellular signal-regulated kinase pathways.
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MC3T3-E1 成骨细胞样细胞中甲状旁腺激素对基质 Gla 蛋白的调节涉及蛋白激酶 A 和细胞外信号调节激酶途径。
DOI：
10.1002/jcb.21314
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发表时间：
2007
影响因子：
4
通讯作者：
Gopalakrishnan,Rajaram
中科院分区：
文献类型：
--
作者：
Suttamanatwong,Supaporn;Franceschi,RennyT;Carlson,AnnE;Gopalakrishnan,Rajaram
抑制成骨细胞介导的矿化是甲状旁腺激素(PTH)对骨的主要分解代谢作用之一。先前，我们发现甲状旁腺激素诱导基质γ-羧谷氨酸蛋白的表达，并证实这种诱导在甲状旁腺素介导的抑制成骨细胞矿化过程中起关键作用。在本研究中，我们重点研究了PTH调节成骨细胞MC3T3-E1中MGP表达的机制。将pMGp748bpmgp启动子-荧光素酶构建体(−-Luc)瞬时转染这些细胞后，−(10-7M)以时间依赖的方式诱导启动子活性，最大诱导量在处理后6h达到4~6倍。H-89(PKA抑制剂)和U0126(MEK抑制剂)均可抑制PTH诱导的MGP启动子活性和MGP mRNA水平。此外，Forskolin(PKA激活剂)刺激MGP启动子活性和mRNA水平，证实PKA是甲状旁腺素调节MGP所需的信号分子之一。将mMGP-Luc与MEK(SP)共转染MC3T3-E1细胞后，MGP启动子活性呈剂量依赖性增加。蛋白激酶C(PKC)抑制剂GF109203X不影响MGP启动子活性和MGP mRNA水平。然而，选择性PKC激活剂佛波酯(PMA)通过激活细胞外信号调节激酶(ERK)诱导MGP mRNA的表达。综上所述，这些结果表明，PTH通过PKA和ERK依赖的途径调节MGP。J.细胞。生物化学。102：496-505,2007。©2007 Wiley-Liss Inc.
Inhibition of osteoblast‐mediated mineralization is one of the major catabolic effects of parathyroid hormone (PTH) on bone. Previously, we showed that PTH induces matrix γ‐carboxyglutamic acid (Gla) protein (MGP) expression and established that this induction is critical for PTH‐mediated inhibition of osteoblast mineralization. In the present study, we focus on the mechanism through which PTH regulates MGP expression in osteoblastic MC3T3‐E1 cells. Following transient transfection of these cells with a −748 bp murine MGP promoter‐luciferase construct (pMGP‐luc), PTH (10−7M) induced promoter activity in a time‐dependent manner with a maximal four‐ to six fold induction seen 6 h after PTH treatment. Both H‐89 (PKA inhibitor) and U0126 (MEK inhibitor), suppressed PTH induction of MGP promoter activity as well as the MGP mRNA level. In addition, forskolin (PKA activator) stimulated MGP promoter activity and mRNA levels confirming that PKA is one of the signaling molecules required for regulation of MGP by PTH. Co‐transfection of MC3T3‐E1 cells with pMGP‐luc and MEK(SP), a plasmid encoding the constitutively active form of MEK, led to a dose‐dependent increase in MGP promoter activity. Both MGP promoter activity and MGP mRNA level were not affected by the protein kinase C (PKC) inhibitor, GF109203X. However, phorbol 12‐myristate 13‐acetate (PMA), a selective PKC activator induced MGP mRNA expression through activation of extracellular signal‐regulated kinase (ERK). Taken together, these results indicate that PTH regulates MGP via both PKA‐ and ERK‐dependent pathways. J. Cell. Biochem. 102: 496–505, 2007. © 2007 Wiley‐Liss, Inc.