MAOA/H202 regulation by Dexamethasone & other Steroids i

地塞米松对 MAOA/H202 的调节

• 批准号: 7296838
• 负责人: Marc Roy Blackman
• 金额: --
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7296838
• 关键词: MAOA; H202; regulation; Dexamethasone; other

Chronic stress is implicated in the pathogenesis of cardiovascular disease, the metabolic syndrome, neurodegeneration, depression and other psychiatric disorders, and inflammatory diseases. Skeletal myopathy and neuronal cell atrophy are common complications of endogenous and exogenous glucocorticoid excess; yet the underlying mechanisms remain unclear and targeted therapeutic interventions are limited. Mitochondria play a pivotal role in cell homeostasis, housing multiple metabolic pathways that result in energy production in the form of ATP. They also generate most cellular reactive oxygen species (ROS) and regulate programmed cell death, serving as a gatekeeper for apoptosis. Not surprisingly, primary or secondary mitochondrial dysfunction have been associated with the pathogenesis of conditions such as obesity, diabetes, cancer, neurodegeneration, cardiomyopathy, depression and aging, of obvious public health significance. Patients with the aforementioned diseases commonly use wide CAM modalities. To systematically study the contribution of mitochondrial genomics to human physiology and pathophysiology, we built a mitochondria-focused gene database and used it as reference for the development of a customized cDNA microarray (hMitChip), containing 501 mitochondria-related nuclear genes. To validate the ability of this mitochondrial microarray to detect changes in gene expression, we explored the pharmacogenomic effects of dexamethasone (Dex), a synthetic glucocorticoid, on the mitochondrial nuclear transcriptome in human skeletal muscle cells. Of the 501 mitochondria related genes arrayed in hMitChip, 23 (4.5%) displayed significant transcriptional changes in skeletal myocytes after treatment with Dex. Upregulation of genes involved in amine metabolism (MAOA and SAT) was statistically significant at all time intervals tested, whereas for genes involved in protein processing (AKAP10), oxidative phosphorylation (FDX1, CYBA), heat shock cellular stress response (HSPD1), lipid biosynthesis (FACL2), glycolysis (GCK) and mitochondrial protein synthesis (TSFM) upregulation was stastistically significant only at certain time points. Treatment for 7 days downregulated genes related to lipid metabolism (ACADVL, ACADM), the tricarboxylic acid cycle (DLST), protein processing (MPI, PPIB) and gene transcription (GABPA), whereas it induced genes involved in apoptosis (BNIP3). The CTNNA1 and AK1 genes, involved in cell adhesion and nucleotide metabolism, respectively, were also significantly downregulated after 7 days of exposure to 10-6 M of Dex. Reproducible results were obtained across multiple replicate experiments, and after reverse labeling of the hybridized slides For selected genes, the transcriptional changes detected with hMitChip were confirmed by QRT-PCR, carried out on RNA from the corresponding microarray experiments, as well as from separate time-course experiments, in which myocytes obtained from two independent healthy male donors were exposed to 10-6 M of Dex for up to 9 days. A significant induction of the MAOA gene was observed at every time point. Fold change increased over time, with a peak induction of 21.2?2.7 vs. untreated cells at day 5. FDX1 expression differed between Dex-treated and control cells at days 3 and 5, whereas FACL2 expression was different on days 5, 7, and 9, but with no significant increase over time. A trend towards downregulation was observed for ACADVL and ACADM after 7 days of exposure to Dex, consistent with the microarray findings, but failed to reach statistical significance. QRT-PCR results for selected genes, which were not differentially expressed in microarray experiments (i.e., NNT1, TOMM70) and were therefore used as negative controls, were also consistent with the microarray findings. We reported that the catecholamine-metabolizing enzyme MAO-A is a major target for glucocorticoids in human skeletal muscle cells. MAO catalyzes the oxidative deamination of neuroactive, vasoactive (serotonin, dopamine, catecholamines), or dietary (tyramine) amines and xenobiotics, releasing reactive aldehydes and H202. MAO-A activation by glucocorticoids with subsequent excess hydrogen peroxide production could represent a novel pathway for glucocorticoid-induced oxidative tissue damage, and MAO-inhibitors or other allopathic and CAM interventions aimed at different components of that pathway may serve as therapeutic agents. Genetic studies have linked MAO-A and MAO-B to various aspects of human behavior, and environmental interactions modulate the expression of certain MAO-A polymorphisms; however, the hormonal regulation of their expression in humans remains unexplored. We have begun to examine the effects of adrenal, gonadal and neurosteroids, in addition to glucocorticoids, on MAO expression in human fetal astrocytes. We hypothesized that estrogen, progesterone, DHEA and/or other neurosteroids (allopreganolone, THDOC) may elicit effectson on MAO expression opposite to those of glucocorticoids . It would appear that hMitChip is a reliable and novel tool that may prove useful for systematically studying the contribution of mitochondrial genomics to human health and disease.

慢性应激与心血管疾病、代谢综合征、神经退行性变、抑郁症和其他精神疾病以及炎症性疾病的发病机制有关。骨骼肌病和神经元细胞萎缩是内源性和外源性糖皮质激素过量的常见并发症；然而，潜在的机制仍不清楚，有针对性的治疗干预措施也有限。 线粒体在细胞稳态中发挥着关键作用，拥有多种代谢途径，从而以 ATP 形式产生能量。它们还产生大多数细胞活性氧（ROS）并调节程序性细胞死亡，充当细胞凋亡的看门人。毫不奇怪，原发性或继发性线粒体功能障碍与肥胖、糖尿病、癌症、神经退行性变、心肌病、抑郁症和衰老等疾病的发病机制有关，具有明显的公共卫生意义。患有上述疾病的患者通常使用广泛的 CAM 模式。 为了系统地研究线粒体基因组学对人类生理学和病理生理学的贡献，我们建立了一个以线粒体为中心的基因数据库，并将其作为开发定制cDNA微阵列（hMitChip）的参考，其中包含501个线粒体相关核基因。为了验证这种线粒体微阵列检测基因表达变化的能力，我们探索了地塞米松（Dex）（一种合成糖皮质激素）对人类骨骼肌细胞线粒体核转录组的药物基因组效应。 hMitChip 中排列的 501 个线粒体相关基因中，有 23 个（4.5%）在 Dex 处理后在骨骼肌细胞中显示出显着的转录变化。在所有测试的时间间隔内，参与胺代谢的基因（MAOA和SAT）的上调具有统计学意义，而参与蛋白质加工（AKAP10）、氧化磷酸化（FDX1、CYBA）、热休克细胞应激反应（HSPD1）、脂质生物合成（FACL2）、糖酵解（GCK）和线粒体蛋白的基因上调 合成（TSFM）上调仅在某些时间点具有统计学意义。 7天的治疗下调与脂质代谢（ACADVL、ACADM）、三羧酸循环（DLST）、蛋白质加工（MPI、PPIB）和基因转录（GABPA）相关的基因，而诱导与细胞凋亡相关的基因（BNIP3）。分别与细胞粘附和核苷酸代谢相关的 CTNNA1 和 AK1 基因在暴露于 10-6 M Dex 7 天后也显着下调。通过多次重复实验以及对杂交载玻片进行反向标记后获得了可重复的结果 对于选定的基因，使用 hMitChip 检测到的转录变化通过 QRT-PCR 得到证实，对来自相应微阵列实验的 RNA 进行，以及来自单独的时间过程实验，其中从两个独立的健康男性供体获得的肌细胞暴露于 10-6 M 的 Dex 长达 9 天。在每个时间点都观察到 MAOA 基因的显着诱导。倍数变化随着时间的推移而增加，与未处理的细胞相比，第 5 天的诱导峰值为 21.2?2.7。Dex 处理的细胞和对照细胞之间的 FDX1 表达在第 3 天和第 5 天存在差异，而 FACL2 表达在第 5 天、第 7 天和第 9 天存在差异，但随着时间的推移没有显着增加。暴露于 Dex 7 天后，观察到 ACADVL 和 ACADM 呈下调趋势，与微阵列结果一致，但未能达到统计学显着性。所选基因的 QRT-PCR 结果也与微阵列结果一致，这些基因在微阵列实验中没有差异表达（即 NNT1、TOMM70），因此用作阴性对照。 我们报道儿茶酚胺代谢酶 MAO-A 是人类骨骼肌细胞中糖皮质激素的主要靶标。 MAO 催化神经活性、血管活性（血清素、多巴胺、儿茶酚胺）或膳食（酪胺）胺和异生物质的氧化脱氨，释放活性醛和 H2O2。糖皮质激素激活 MAO-A，随后产生过量过氧化氢，可能代表糖皮质激素诱导的氧化组织损伤的新途径，而针对该途径不同成分的 MAO 抑制剂或其他对抗疗法和 CAM 干预措施可以作为治疗剂。 遗传学研究已将 MAO-A 和 MAO-B 与人类行为的各个方面联系起来，环境相互作用可调节某些 MAO-A 多态性的表达；然而，它们在人类中表达的激素调节仍有待探索。除了糖皮质激素外，我们还开始研究肾上腺、性腺和神经类固醇对人胎儿星形胶质细胞 MAO 表达的影响。我们假设雌激素、孕激素、DHEA 和/或其他神经类固醇（别加醇酮，THDOC）可能对 MAO 表达产生与糖皮质激素相反的影响。 hMitChip 似乎是一种可靠且新颖的工具，可能有助于系统地研究线粒体基因组学对人类健康和疾病的贡献。