Juhász Tamás, Matta Csaba, Katona Éva, Somogyi Csilla, Takács Roland, Hajdú Tibor, Helgadottir Solveig Lind, Fodor János, Csernoch László, Tóth Gábor, Bakó Éva, Reglődi Dóra, Tamás Andrea, Zákány Róza
Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, H-4032, Debrecen, Hungary.
J Mol Neurosci. 2014 Nov;54(3):555-73. doi: 10.1007/s12031-014-0389-1. Epub 2014 Aug 12.
Presence of the pituitary adenylate cyclase-activating polypeptide (PACAP) signalling has been proved in various peripheral tissues. PACAP can activate protein kinase A (PKA) signalling via binding to pituitary adenylate cyclase-activating polypeptide type I receptor (PAC1), vasoactive intestinal polypeptide receptor (VPAC) 1 or VPAC2 receptor. Since little is known about the role of this regulatory mechanism in bone formation, we aimed to investigate the effect of PACAP on osteogenesis of UMR-106 cells. PACAP 1-38 as an agonist and PACAP 6-38 as an antagonist of PAC1 were added to the culture medium. Surprisingly, both substances enhanced protein expressions of collagen type I, osterix and alkaline phosphatase, along with higher cell proliferation rate and an augmented mineralisation. Although expression of PKA was elevated, no alterations were detected in the expression, phosphorylation and nuclear presence of CREB, but increased nuclear appearance of Runx2, the key transcription factor of osteoblast differentiation, was shown. Both PACAPs increased the expressions of bone morphogenetic proteins (BMPs) 2, 4, 6, 7 and Smad1 proteins, as well as that of Sonic hedgehog, PATCH1 and Gli1. Data of our experiments indicate that activation of PACAP pathway enhances bone formation of UMR-106 cells and PKA, BMP and Hedgehog signalling pathways became activated. We also found that PACAP 6-38 did not act as an antagonist of PACAP signalling in UMR-106 cells.
垂体腺苷酸环化酶激活多肽（PACAP）信号通路已在多种外周组织中得到证实。PACAP可通过与I型垂体腺苷酸环化酶激活多肽受体（PAC1）、血管活性肠肽受体（VPAC）1或VPAC2受体结合来激活蛋白激酶A（PKA）信号通路。由于对这种调节机制在骨形成中的作用了解甚少，我们旨在研究PACAP对UMR-106细胞成骨作用的影响。将PACAP 1-38作为激动剂和PACAP 6-38作为PAC1的拮抗剂添加到培养基中。令人惊讶的是，这两种物质均增强了I型胶原蛋白、osterix和碱性磷酸酶的蛋白表达，同时细胞增殖率更高且矿化增强。尽管PKA的表达升高，但未检测到CREB的表达、磷酸化和核内存在情况有改变，不过成骨细胞分化的关键转录因子Runx2的核内出现增加。两种PACAP均增加了骨形态发生蛋白（BMP）2、4、6、7和Smad1蛋白的表达，以及音猬因子、PATCH1和Gli1的表达。我们的实验数据表明，PACAP信号通路的激活增强了UMR-106细胞的骨形成，并且PKA、BMP和Hedgehog信号通路被激活。我们还发现，PACAP 6-38在UMR-106细胞中并非作为PACAP信号的拮抗剂发挥作用。
