Mechanisms for Ceramide Mediated Vascular Dysfunction

神经酰胺介导的血管功能障碍的机制

• 批准号: 8366869
• 负责人: John David SYMONS
• 金额: $ 43.66万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8366869
• 关键词: Academic Research Enhancement Awards; Acute; Address; Adipose tissue; Agonist; Anabolism; Animal Feed; Arteries; Attenuated; Biological Availability; Blood Pressure; Blood Vessels; Cardiovascular system; Cause of Death; Ceramides; Characteristics; Chronic; Complex; Complication; Data; Defect; Dentistry; Development; Diabetes Mellitus; Diet; Discipline of Nursing; Doctor of Philosophy; Education; Endothelial Cells; Endothelium; Enzymes; Experimental Models; Exposure to; Fatty acid glycerol esters; Fostering; Functional disorder; Gender; Genetic; Hypertension; Impairment; Individual; Infusion procedures; Insulin Resistance; Laboratories; Lead; Link; Lipids; Liver; Manuscripts; Mediating; Medicine; Membrane; Metabolic; Mitogen-Activated Protein Kinase 3; Modeling; Molecular; Mus; Nitric Oxide; Nitric Oxide Synthase; Non-Insulin-Dependent Diabetes Mellitus; Nonesterified Fatty Acids; Obesity; Palmitates; Patients; Peroxonitrite; Pharmacy facility; Phosphorylation; Phosphotransferases; Physical therapy; Prevalence; Production; Protein phosphatase; Repression; Research; Research Personnel; Research Project Grants; Risk; Science; Secondary to; Signal Transduction; Skeletal Muscle; Sphingolipids; Superoxides; Testing; Tissues; Training; United States; United States National Institutes of Health; Vascular Diseases; Vasodilation; age group; ceramide-activated protein phosphatase; clinically relevant; design; diabetic; dihydroceramide desaturase; dimer; enzyme activity; experience; feeding; human NOS3 protein; in vivo; insight; novel; prevent; programs; protein phosphatase 2A inhibitor 2; research study; thermozymocidin

DESCRIPTION (provided by applicant): Patients with diet-induced obesity and type 2 diabetes are at greater risk for developing cardiovascular complications. An important complication is impaired blood vessel function. In a clinically relevant murine model of diet-induced obesity we showed that exposure to elevated free fatty acids (FFAs) reduces nitric oxide (NO) bioavailability leading to arterial dysfunction. My 2007 R15 sought to determine whether the signaling link between elevated FFAs and impaired NO bioavailability involves the lipid metabolite ceramide. Inhibition of ceramide synthesis with myriocin, or heterozygous deletion of dihydroceramide desaturase, an enzyme which catalyzes ceramide synthesis, prevented endothelial dysfunction and systemic hypertension, and preserved endothelial NO synthase (eNOS) phosphorylation in arteries from fat-fed mice. Molecular mechanisms whereby ceramide might lower NO bioavailability were examined using cultured endothelial cells. Palmitate induced repression of basal and agonist-stimulated eNOS phosphorylation, eNOS dimer formation, and NO production were restored following inhibition of ceramide synthesis. The ceramide-induced impairment of eNOS phosphorylation or dimer formation, respectively, was not the result of impaired kinase-mediated eNOS phosphorylation or superoxide anion-mediated peroxynitrite formation. [Instead, ceramide causes protein phosphatase 2A (PP2A) to associate directly with the eNOS/Akt complex, and this is concurrent with decreased basal and agonist-stimulated eNOS phosphorylation. New data obtained since the last submission suggest that PP2A attenuates eNOS phosphorylation by preventing phosphorylation of the pool of Akt that colocalizes with eNOS and / or by directly dephosphorylating eNOS.] In this renewal, Aim 1 will test the hypothesis that PP2A associates with and disrupts the Akt-Hsp90-eNOS complex as a consequence of de novo ceramide synthesis leading to impaired basal and agonist-stimulated eNOS phosphorylation. Aim 2 will test the hypothesis that ceramide relieves the association of inhibitor 2 of PP2A (I2PP2A) with PP2A such that PP2A can translocate to the membrane and associate with eNOS. Aim 3 will test the hypothesis that ceramide-induced, PP2A-mediated vascular dysfunction occurs in mice with diet-induced obesity. Results from these studies will provide mechanistic insight linking endogenous vascular ceramide biosynthesis to cardiovascular defects in a murine model of diet-induced obesity and type 2 diabetes, and present new targets for the treatment of vascular dysfunction in these prevalent conditions. Support for our research via the NIH R15 mechanism has provided > 35 undergraduate researchers with valuable experience and each has continued to pursue an advanced degree in the biomedical sciences. PUBLIC HEALTH RELEVANCE: Obesity can lead to type 2 diabetes and cardiovascular complications. Our research is focused on determining the mechanisms whereby obesity impairs blood vessel function. We will determine the mechanism whereby the fat metabolite ceramide impairs eNOS enzyme activity and precipitates arterial dysfunction.

描述（由申请人提供）：饮食引起的肥胖症和2型糖尿病患者患心血管并发症的风险更大。一个重要的并发症是血管功能受损。在临床相关的饮食诱导肥胖症的鼠模型中，我们表明暴露于升高的游离脂肪酸（FFA）会降低一氧化氮（NO）生物利用度，导致动脉功能障碍。我的2007年R15试图确定升高的FFA和受损无生物利用度之间的信号连接是否涉及脂质代谢物神经酰胺。用肉豆蔻素抑制神经酰胺的抑制作用，或二氢可酰胺去饱和酶的杂合缺失，一种酶，一种催化神经酰胺合成的酶，防止了内皮功能障碍和全身性高血压，并保留了内皮的无内皮合酶（eNOS）磷酸化磷酸化的内皮合酶（eNOS）无磷脂的磷酸化。通过培养的内皮细胞，神经酰胺可能降低了无法降低神经酰胺的分子机制。棕榈酸酯诱导的抑制基底和激动剂刺激的eNOS磷酸化，eNOS二聚体形成以及在抑制神经酰胺合成后未恢复产生。神经酰胺诱导的eNOS磷酸化或二聚体形成的损伤并不是激酶介导的eNOS磷酸化或超氧化物阴离子介导的过氧亚硝酸盐形成的结果。 [相反，神经酰胺会导致蛋白质磷酸酶2a（PP2A）直接与eNOS/AKT复合物缔合，这与基底和激动剂刺激的eNOS磷酸化降低并发。自上次提交以来获得的新数据表明，PP2A通过防止AKT库的磷酸化来减轻ENOS磷酸化，而Akt的池与ENOS和 /或直接通过dephosphorytrating Enos共同定位。导致基底和激动剂刺激的eNOS磷酸化受损。 AIM 2将测试神经酰胺可以缓解PP2A（I2PP2A）与PP2A的抑制剂2的缔合的假设，使PP2A可以转移到膜并与ENOS相关。 AIM 3将检验神经酰胺诱导的PP2A介导的血管功能障碍的假设，发生在饮食诱导的肥胖症的小鼠中。这些研究的结果将提供机械洞察力，将内源性血管神经酰胺生物合成与心血管缺陷联系起来，在饮食诱导的肥胖症和2型糖尿病的鼠模型中，并为在这些普遍条件下的血管功能障碍治疗血管功能障碍。通过NIH R15机制为我们的研究提供了支持，为35位本科研究人员提供了宝贵的经验，并且每个研究人员都继续攻读生物医学科学的高级学位。 公共卫生相关性：肥胖可能导致2型糖尿病和心血管并发症。我们的研究重点是确定肥胖会损害血管功能的机制。我们将确定脂肪代谢物神经酰胺会损害eNOS酶活性并沉淀动脉功能障碍的机制。

项目成果

Opportunity "nox": a novel approach to preventing endothelial dysfunction in the context of insulin resistance.

• DOI: 10.2337/db13-0255
• 发表时间: 2013-06
• 期刊: Diabetes
• 影响因子: 7.7
• 作者: Symons JD

Role of Endothelial Cells in Myocardial Ischemia-Reperfusion Injury.

• DOI: 10.2174/1874120701007010001
• 发表时间: 2010
• 期刊: Vascular disease prevention
• 作者: Singhal AK;Symons JD;Boudina S;Jaishy B;Shiu YT
• 通讯作者: Shiu YT

Impairment of autophagy in endothelial cells prevents shear-stress-induced increases in nitric oxide bioavailability.

• DOI: 10.1139/cjpp-2014-0017
• 发表时间: 2014-07
• 期刊: Canadian journal of physiology and pharmacology
• 影响因子: 2.1
• 作者: Bharath LP;Mueller R;Li Y;Ruan T;Kunz D;Goodrich R;Mills T;Deeter L;Sargsyan A;Anandh Babu PV;Graham TE;Symons JD
• 通讯作者: Symons JD

Fasting-induced reductions in cardiovascular and metabolic variables occur sooner in obese versus lean mice.

肥胖小鼠与瘦小鼠相比，禁食引起的心血管和代谢变量的减少发生得更快。

• DOI: 10.1258/ebm.2010.010171
• 发表时间: 2010
• 期刊: Experimental biology and medicine (Maywood, N.J.)
• 作者: Tanner,JasonM;Kearns,DevinT;Kim,BumJun;Sloan,Crystal;Jia,Zhanjun;Yang,Tianxin;Abel,EDale;Symons,JDavid
• 通讯作者: Symons,JDavid