Virdi A S, Cook L J, Oreffo R O, Triffitt J T
Nuffield Department of Orthopaedic Surgery, University of Oxford, Nuffield Orthopaedic Centre, Headington, England.
Cell Mol Biol (Noisy-le-grand). 1998 Dec;44(8):1237-46.
Bone morphogenetic proteins (BMPs) belong to the transforming growth factor-beta (TGF-beta) superfamily and are crucial factors in the process of bone formation. Despite knowledge on their wide distribution and expression, however, there is very little information on the biological factors that affect gene transcription of these osteoinductive agents. To investigate this aspect of BMP gene regulation we have studied the effect of a number of factors known to affect osteogenic cells. Northern analysis showed modulation of the expression of BMP-2 and BMP-4 mRNAs in two human osteosarcoma cell lines, MG63 and Saos-2, by prostaglandin E2 (PGE2), interleukin-1beta (IL-1beta), interleukin-6 (IL-6), interferon-alpha (IFN-alpha), retinoic acid and 1,25(OH)2 vitamin D3. mRNA expressions of the normally used "housekeeping genes", glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and beta-actin, were found to be susceptible to influence by some of the factors used. Hence, an oligo(dT)15-18 probe was used to reliably estimate the relative quantities of mRNA present for normalization of data. In general, all factors down-regulated mRNA expressions of BMP-2 and BMP-4 in MG63 cells. IL-6 completely abolished detectable expression of BMP-2 mRNA, which was also greatly reduced by IL-1beta, retinoic acid and 1,25(OH)2 vitamin D3. PGE2 had similar influences on BMP-2 and BMP-4 expressions, showing reductions to approximately 60% of normal. In Saos-2 cells only 1,25(OH)2 vitamin D3 had any great effect on BMP-2 expression, which was down-regulated to approximately 60% of control values. BMP-4 was down-regulated by IFN-alpha (approximately 60%) and IL-1beta (approximately 20%). We conclude that BMPs are subject to regulation by a variety of factors and that this is dependent on the stage of the cell in the osteogenic lineage. Furthermore, the use of GAPDH and beta-actin genes as "housekeeping genes" in expression-modulation studies must be treated with care.
骨形态发生蛋白（BMPs）属于转化生长因子-β（TGF-β）超家族，是骨形成过程中的关键因子。然而，尽管已知它们分布广泛且有表达，但关于影响这些骨诱导因子基因转录的生物学因素的信息却非常少。为了研究BMP基因调控的这一方面，我们研究了一些已知影响成骨细胞的因素的作用。Northern分析显示，前列腺素E2（PGE2）、白细胞介素-1β（IL-1β）、白细胞介素-6（IL-6）、干扰素-α（IFN-α）、视黄酸和1,25（OH）2维生素D3对两种人骨肉瘤细胞系MG63和Saos-2中BMP-2和BMP-4 mRNA的表达有调节作用。发现常用的“管家基因”甘油醛-3-磷酸脱氢酶（GAPDH）和β-肌动蛋白的mRNA表达易受所用某些因素的影响。因此，使用寡聚（dT）15-18探针来可靠地估计存在的mRNA的相对量，以便对数据进行归一化。一般来说，所有因素均下调MG63细胞中BMP-2和BMP-4的mRNA表达。IL-6完全消除了可检测到的BMP-2 mRNA表达，IL-1β、视黄酸和1,25（OH）2维生素D3也使其大幅降低。PGE2对BMP-2和BMP-4的表达有类似影响，使其降低至正常水平的约60%。在Saos-2细胞中，只有1,25（OH）2维生素D3对BMP-2表达有显著影响，使其下调至对照值的约60%。BMP-4被IFN-α（约60%）和IL-1β（约20%）下调。我们得出结论，BMPs受到多种因素的调控，且这取决于成骨谱系中细胞的阶段。此外，在表达调控研究中使用GAPDH和β-肌动蛋白基因作为“管家基因”时必须谨慎对待。
