Endothelial Lipoxygenase Metabolites and Vascular Tone

内皮脂氧合酶代谢物和血管张力

• 批准号: 8105577
• 负责人: WILLIAM BRYSON CAMPBELL
• 金额: $ 37.3万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8105577
• 关键词: Acetylcholine; Acids; Address; Agonist; Angiotensin II; Angiotensins; Apamin; Arachidonate 15-Lipoxygenase; Arachidonic Acids; Arteries; Binding; Binding Sites; Biochemical; Biological Assay; Blood Pressure; Blood Vessels; Calcium; Cardiovascular Diseases; Cell membrane; Cells; Cholesterol; Contractile Proteins; Coupled; Diabetes Mellitus; Eicosatrienoic Acid; Endothelial Cells; Endothelium; Endothelium-Dependent Relaxing Factors; Epoprostenol; Functional disorder; G-substrate; GTP Binding; GTP-Binding Proteins; Goals; Guanosine Triphosphate; Health; Heart failure; Heterotrimeric GTP-Binding Proteins; Hypertension; Hypoxia; Innovative Therapy; Interleukins; Knowledge; Link; Lipoxygenase; Mediating; Membrane; Methods; Molecular; Molecular Mechanisms of Action; Monomeric GTP-Binding Proteins; Myocardial Ischemia; Myosin Light Chains; Nitric Oxide; Nitric Oxide Synthase; Norepinephrine; Oryctolagus cuniculus; Pathway interactions; Potassium; Potassium Channel; Prostaglandin-Endoperoxide Synthase; Proteins; Regulation; Relaxation; Rho-associated kinase; Role; Signal Pathway; Smooth Muscle Myocytes; Testing; Therapeutic; Vascular Diseases; Vasoconstrictor Agents; Vasodilator Agents; angiotensin hypertension; blood pressure regulation; constriction; cyclooxygenase 2; guanine nucleotide binding protein; improved; insight; myosin phosphatase; novel; novel strategies; novel therapeutic intervention; patch clamp; phospholipase inhibitor; receptor; relaxing factor; vasoconstriction

DESCRIPTION (provided by applicant): Endothelial cells release nitric oxide, prostaglandin I2 and endothelium-derived hyperpolarizing factor (EDHF) that reduce vascular tone and counteract vasoconstriction. Ischemic heart disease, heart failure and hyperten- sion are associated with vasoconstriction that is attributed, in part, to reductions in endothelium-dependent di- lation. Therapeutic approaches restoring endothelial function represent promising new treatments for cardio- vascular diseases with a major impact on health. We have identified a 15-lipoxygenase (LO) metabolite of ara- chidonic acid, 11(R),12(S),15(S)-trihydroxy-eicosatrienoic acid (11,12,15-THETA), that acts as an EDHF. It relax arteries, in part, by activating apamin-sensitive, small conductance, calcium-activated potassium (SKCa) channels and hyperpolarizing smooth muscle cells (SMCs). It also acts by inhibition of RhoA activation. 11,12,15-THETA mediates a portion of the endothelium-dependent relaxations to acetylcholine (ACh), in- creases in flow and AA and opposes the action of vasoconstrictors. We will test the hypothesis that 11,12,15- THETA mediates relaxations to ACh and AA by a unique combination of mechanisms: (1) activating a hetero- trimeric guanine nucleotide binding protein (G protein) that opens SKCa channels resulting in hyperpolarization of SMCs and (2) inhibiting the activation of the small GTPase RhoA reducing the calcium sensitivity of contrac- tile proteins. These studies will indicate that 11,12,15-THETA is an EDHF and an endothelium-derived calcium (Ca) desensitizer. 11(R),12(S),15(S)-THETA increases GTP335S binding to rabbit arterial membranes implicat- ing a G protein-coupled binding site/receptor. Using biochemical and molecular methods, we will identify the G protein(s) that is coupled to 11,12,15-THETA action. Using patch clamp and bioassay methods, we will char- acterize the role of the G protein in the regulation of SKCa channel activity, hyperpolarization and dilation by 11,12,15-THETA. These studies will provide new insights into the molecular mechanism of action of 11,12,15- THETA and the regulation of vascular SKCa channel activity. Agonists such as norepinephrine and angiotensin promote constriction by activating the RhoA-Rho kinase cascade that sensitizes contractile proteins to Ca. 11,12,15-THETA decreases the formation of the active form of RhoA, RhoA-GTP. These studies will test the hypothesis that 11,12,15-THETA causes relaxation by inhibiting RhoA activation resulting in decreased Rho kinase activity increasing myosin light chain phosphatase activity and decreasing phosphorylated myosin light chain. These studies will access the effect of 11,12,15-THETA on RhoA activity in SMCs and arteries and de- termine the contribution of RhoA inhibition to the relaxations to 11,12,15-THETA. The role of a G protein in RhoA inhibition by 11,12,15-THETA will be determined. These studies will identify two new mechanisms of action for the endothelium-derived relaxing factor 11,12,15-THETA and provide a new therapeutic approach to enhancing endothelial function. PUBLIC HEALTH RELEVANCE: The local regulation of the dilation and constriction of blood vessels is important in normal blood pressure control and contributes to pathological conditions as hypertension, diabetes and angina. These studies have defined a new class of vasodilators that are formed by the blood vessel wall. Knowledge of the mechanisms of action of these new endogenous vasodilators will help our understanding of the regulation of vascular tone and blood pressure.

描述（由申请方提供）：内皮细胞释放一氧化氮、前列腺素I2和内皮源性超极化因子（EDHF），降低血管张力并对抗血管收缩。缺血性心脏病、心力衰竭和高锡永与血管收缩有关，部分原因是内皮依赖性扩张减少。恢复内皮功能的治疗方法代表了对健康有重大影响的心血管疾病的有希望的新治疗。我们已经鉴定了花生四烯酸的15-脂氧合酶（LO）代谢产物11（R），12（S），15（S）-三羟基-二十碳三烯酸（11，12，15-THETA），其作为EDHF起作用。它部分通过激活apamin敏感的小电导钙激活钾（SKCa）通道和超极化平滑肌细胞（SMC）来放松动脉。它还通过抑制RhoA活化起作用。11，12，15-THETA介导一部分乙酰胆碱（ACh）的内皮依赖性舒张，增加流量和AA，并对抗血管收缩剂的作用。我们将检验11，12，15- THETA通过以下机制的独特组合介导对ACh和AA的舒张的假设：（1）激活异源三聚体鸟嘌呤核苷酸结合蛋白（G蛋白），其打开SKCa通道，导致SMC的超极化，和（2）抑制小GTTR RhoA的激活，降低收缩蛋白的钙敏感性。这些研究将表明，11，12，15-THETA是一种EDHF和内皮源性钙（Ca）脱敏剂。11（R），12（S），15（S）-THETA增加GTP 335 S与兔动脉膜的结合，暗示G蛋白偶联结合位点/受体。利用生物化学和分子生物学方法，我们将鉴定与11，12，15-THETA作用偶联的G蛋白。本实验采用膜片钳技术和生物活性测定方法，研究G蛋白在11，12，15-THETA调节SKCa通道活性、超极化和扩张中的作用。这些研究将为11，12，15- THETA的分子作用机制和血管SKCa通道活性的调节提供新的见解。激动剂如去甲肾上腺素和血管紧张素通过激活RhoA-Rho激酶级联来促进收缩，所述RhoA-Rho激酶级联使收缩蛋白对Ca敏感。11，12，15-THETA减少RhoA活性形式RhoA-GTP的形成。这些研究将检验11，12，15-THETA通过抑制RhoA活化导致Rho激酶活性降低、肌球蛋白轻链磷酸酶活性增加和磷酸化肌球蛋白轻链减少而引起松弛的假设。这些研究将评估11，12，15-THETA对SMC和动脉中RhoA活性的影响，并确定RhoA抑制对11，12，15-THETA舒张的贡献。将确定G蛋白在11，12，15-THETA抑制RhoA中的作用。这些研究将确定内皮源性舒张因子11，12，15-THETA的两种新的作用机制，并为增强内皮功能提供新的治疗方法。 公共卫生关系：血管扩张和收缩的局部调节在正常血压控制中是重要的，并且有助于高血压、糖尿病和心绞痛等病理状况。这些研究已经定义了一类由血管壁形成的新的血管扩张剂。了解这些新的内源性血管扩张剂的作用机制将有助于我们理解血管张力和血压的调节。