Functional significance of a single nucleotide polymorphism in the gene encoding endothelial nitric oxide synthase

内皮一氧化氮合酶基因编码单核苷酸多态性的功能意义

• 批准号: 321001878
• 负责人: Professor Dr. Markus Hecker, Ph.D.
• 金额: --
• 依托单位: Institut für Physiologie und Pathophysiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/321001878?language=en
• 关键词: Functional; significance; single; nucleotide; polymorphism

A single nucleotide polymorphism (SNP) within the promoter of the endothelial nitric oxide (NO) synthase (NOS3) gene (T-786C, rs2070744) adversely affects the response of endothelial cells (EC) from CC-genotype individuals to shear stress or the prototypic anti-type 1 T-helper (Th1) cell cytokine interleukin-10. Homozygosity for the C-allele, which occurs in about 12% of Caucasians, is a strong predictor for coronary heart disease, polymyalgia rheumatica or rheumatoid arthritis. In a preceding DFG-funded project, we identified a compensatory mechanism involving manganese-dependent superoxide dismutase that helps to maintain the bioavailability of EC-derived NO. With the shear stress-stimulated release of 15-deoxy-delta12,14-prostaglandin J2 (15d-PGJ2) from CC- but not TT-genotype ECs, we have characterised another compensatory mechanism that may not only support the anti-inflammatory capacity of the CC-genotype ECs but also act as a novel general defence mechanism against chronic inflammation. Moreover, data acquired since then point to a possible epigenetic control of NOS3 expression through chromatin remodelling that may differ in at least two aspects between CC- and TT-genotype ECs. With this proposal we plan to (i) establish that STAT3-guided recruitment of the histone-acetyltransferase p300/CBP and/or the histone-lysine N-methyltransferase SETD7 to the CpG-dinucleotide at position -786 in the NOS3 gene (CC-genotype) and the degree of histone H3 acetylation and/or methylation associated therewith results in a different accessibility, e.g. by STAT3, of the distal NOS3 promoter. Alternatively, p300/CBP may serve as a scaffold coordinating the binding of, e.g. STAT3 to its cis-acting element at position -850 to -842, thereby enabling and/or accelerating trans-activation of the NOS3 gene. Moreover, by (ii) generating the corresponding knock-in mice harbouring the human C- or T-type NOS3 promoter on a disease-susceptible genetic background, we plan to verify that the T-786C SNP of the human NOS3 gene, if present, boosts the development of arteriosclerosis and/or arthritis in these animals. The reason for this complex experimental approach is that instead of the 5'-GGC(T->C)GG-3' motif found in humans the murine Nos3 promoter contains a 5'-GGCCAT-3'motif so that the suspected critical CpG-dinucleotide cannot form. Finally, we plan to (iii) corroborate in an in vitro transmigration model mimicking shear stress conditions at arteriosclerosis predilection sites that the T-786C SNP of the human NOS3 gene differentially affects Th1 and Th17 cell-endothelial cell interaction, respectively, through 15d-PGJ2. Furthermore, we will extend our analysis of the plasma levels of 15d-PGJ2 to patients with rheumatoid arthritis to prove that this prostanoid is both a marker and a pivotal constituent of a novel anti-inflammatory defence mechanism.

内皮型一氧化氮合酶（NOS 3）基因（T-786 C，rs 2070744）启动子内的单核苷酸多态性（SNP）对CC基因型个体的内皮细胞（EC）对剪切应力或原型抗1型T辅助细胞（Th 1）细胞因子白细胞介素-10的反应产生不利影响。C等位基因的纯合性，发生在约12%的高加索人中，是冠心病、风湿性多肌痛或类风湿性关节炎的强预测因子。在之前DFG资助的项目中，我们确定了一种涉及锰依赖性超氧化物歧化酶的补偿机制，该机制有助于维持EC衍生的NO的生物利用度。（15 d-PGJ 2）来自CC基因型EC而非TT基因型EC，我们已经表征了另一种补偿机制，其不仅可以支持CC基因型EC的抗炎能力，而且还可以作为对抗慢性炎症的新的一般防御机制。此外，从那时起获得的数据指向一个可能的表观遗传控制NOS 3表达通过染色质重塑，可能在CC和TT基因型EC之间的至少两个方面不同。通过该提议，我们计划（i）确定STAT 3引导的组蛋白乙酰转移酶p300/CBP和/或组蛋白赖氨酸N-甲基转移酶SETD 7向NOS 3基因中-786位的CpG-二核苷酸的募集（CC-基因型）以及与之相关的组蛋白H3乙酰化和/或甲基化的程度导致远端NOS 3启动子的不同可接近性，例如通过STAT 3。或者，p300/CBP可以作为协调例如STAT 3与其顺式作用元件在位置-850至-842处的结合的支架，从而使得能够和/或加速NOS 3基因的反式激活。此外，通过（ii）在疾病易感遗传背景上产生携带人C型或T型NOS 3启动子的相应敲入小鼠，我们计划验证人NOS 3基因的T-786 C SNP（如果存在）促进这些动物中动脉硬化和/或关节炎的发展。这种复杂的实验方法的原因是，鼠Nos 3启动子含有5 ′-GGCCAT-3 ′基序，而不是在人中发现的5 ′-GGC（T->C）GG-3 ′基序，因此不能形成可疑的关键CpG-二核苷酸。最后，我们计划（iii）在模拟动脉硬化好发部位切应力条件的体外迁移模型中证实，人NOS 3基因的T-786 C SNP通过15 d-PGJ 2分别差异性地影响Th 1和Th 17细胞与内皮细胞的相互作用。此外，我们将扩展我们的15 d-PGJ 2的血浆水平的分析，类风湿性关节炎患者，以证明这种前列腺素既是一种标志物，也是一种新的抗炎防御机制的关键组成部分。