Cardiac Myocyte-Specific Role of PKG I Alpha in Aging-Dependent Cardiac Remodelin

PKG I Alpha 在衰老依赖性心脏重塑中的心肌细胞特异性作用

• 批准号: 8341989
• 负责人: Robert Morris Blanton
• 金额: $ 7.95万
• 依托单位: TUFTS MEDICAL CENTER
• 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 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8341989
• 关键词: Address; Adverse effects; Aging; Blood Vessels; Cardiac; Cardiac Myocytes; Cells; Chronic; Clinical; Congestive Heart Failure; Cyclic GMP-Dependent Protein Kinases; Data; Development; Disease; Elderly; Employee Strikes; Functional disorder; Goals; Heart; Heart failure; Hypertrophy; In Vitro; Knockout Mice; Laboratories; Left Ventricular Hypertrophy; Left ventricular structure; Leucine Zippers; MAP Kinase Kinase Kinase; MAPK8 gene; Medical; Modeling; Morbidity - disease rate; Mus; Mutation; Pathologic; Pathway interactions; Patients; Phenotype; Phosphorylation; Phosphotransferases; Prevention; Process; Proteins; Risk Factors; Role; Signal Pathway; Signal Transduction; Signaling Molecule; Stress; Structure; Syndrome; Testing; Time; Translating; Work; age related; base; cGMP-dependent protein kinase I; clinically relevant; constriction; experience; in vivo; in vivo Model; inhibitor/antagonist; innovation; mixed lineage kinase 3; mortality; mouse model; mutant; neuronal cell body; new therapeutic target; novel; older patient; outcome forecast; phosphodiesterase V; pressure; response; sildenafil; stressor; treatment strategy

DESCRIPTION (provided by applicant): This new R03 proposal explores the mechanisms through which the cGMP-dependent protein kinase I alpha (PKGI¿) inhibits aging-related cardiac remodeling in vivo. It is based on extensive new and unpublished data performed in the PI's laboratory. Preliminary studies have explored the cardiac remodeling response in a mouse model harboring discrete mutations in the PKGI¿ leucine zipper interacting domain (the PKGI¿ leucine zipper mutant, or LZM, mouse). In the baseline state, the LZM mice develop progressive, age-related left ventricular hypertrophy (LVH), a key component of remodeling. In the setting of LV pressure overload, a common risk factor in elderly patients, the LZM mice develop increased LVH, worsening contractile function, and striking accelerated mortality, compared with wild type littermate controls. These data reveal a novel role of PKGI¿ in inhibiting aging-related cardiac remodeling in vivo. We have further identified early blunting of the anti-remodeling JNK pathway in hearts of LZM mice after TAC, compared with WT TAC hearts, and have identified a novel interaction of PKGI¿ with the upstream MAPKKK and JNK activator mixed lineage kinase 3 (MLK3). These preliminary data support a mechanism by which PKGI¿, via interaction with MLK3, activates JNK to inhibit aging-related cardiac remodeling. Based on these, and other, preliminary data, this application proposes to test the central hypothesis that PKGI¿ and its downstream targets in the cardiac myocyte serve as novel targets to treat aging-related cardiac remodeling. We propose to test this hypothesis through three specific aims, using a number of mouse models. In SA1 we will explore the mechanisms by which PKGI¿ inhibits age-dependent LVH and remodeling in vivo, by examining the cardiac structure and function of a new cardiac myocyte-specific PKGI¿ knockout mouse (PKGI¿cKO) created in our laboratory. We will also isolate cardiac myocytes (CMs) from PKGI¿cKO mice to explore the cellular mechanisms by which PKGI¿ inhibits remodeling. In SA2 we will explore the response of the PKGI¿cKO mice to LV pressure overload induced by TAC, and will test the degree to which CM specific PKGI¿ deletion abolishes the anti-remodeling effect of the phosphodiesterase 5 inhibitor sildenafil. In SA3 we will explore the cardiac remodeling response in a whole body MLK3 knockout mouse (MLK3-/-) to test the clinically relevant hypothesis that the PKGI¿-interacting protein MLK3 inhibits aging-related remodeling in vivo. These proposed studies will define the specific mechanisms through which PKGI¿ in the CM inhibits cardiac remodeling. This project is highly significant because it directly addresses a problem which is highly prevalent in the elderly and because it directly tests new therapeutic targets. It is highly innovative because it uses unique in vivo models, and also because it employs an innovative strategy of exploring CM-specific regulators of cardiac remodeling, which could translate into novel, CM-specific treatments. PUBLIC HEALTH RELEVANCE: In the elderly, the disease of congestive heart failure is a major cause of morbidity and mortality, and carries a worse prognosis in elderly patients compared with younger patients. Heart failure results from a process termed cardiac remodeling. Our proposed project studies cardiac remodeling to try to find new treatment strategies for heart failure in the elderly. This project is based on extensive new data and proposes to examine a pathway which may be of direct importance in limiting the cardiac remodeling process. The goals of the project are to understand the role of this new pathway (called the PKGI¿ pathway) in a specific cell of the body, called the cardiac myocyte. The ultimate promise of this work is that, by showing how PKGI¿ works in the cardiac myocyte, it might suggest new medical treatments which take advantage of PKGI¿ activity in these cells, which is particularly relevant to aging patients.

描述（由申请人提供）：这项新的 R03 提案探讨了 cGMP 依赖性蛋白激酶 I α (PKGI¿) 抑制体内衰老相关心脏重塑的机制。它基于 PI 中进行的大量新的和未发表的数据。实验室的初步研究探索了 PKGI 离散突变小鼠模型的心脏重塑反应。亮氨酸拉链相互作用结构域（PKGI¿ 亮氨酸拉链突变体，或 LZM，小鼠）在基线状态下，LZM 小鼠会出现进行性的、与年龄相关的左心室肥厚 (LVH)，这是 LV 重塑的关键组成部分。压力超负荷是老年患者的常见危险因素，与野生型同窝对照小鼠相比，LZM 小鼠的 LVH 增加，收缩功能恶化，死亡率显着加快。这些数据揭示了一个新的结果。 PKGI 的作用??与 WT TAC 心脏相比，我们进一步确定了 TAC 后 LZM 小鼠心脏中抗重塑 JNK 通路的早期钝化，并确定了 PKGI 的新相互作用。与上游 MAPKKK 和 JNK 激活剂混合谱系激酶 3 (MLK​​3) 这些初步数据支持 PKGI 的机制。通过与 MLK3 相互作用，激活 JNK 抑制与衰老相关的心脏重塑。基于这些和其他初步数据，本申请提出测试 PKGI 的中心假设。及其在心肌细胞中的下游靶点作为治疗与衰老相关的心脏重塑的新靶点，我们建议通过三个特定目标来检验这一假设，在 SA1 中，我们将探索 PKGI 的机制。通过检查新心肌细胞特异性 PKGI 的心脏结构和功能，抑制年龄依赖性 LVH 和体内重塑。我们的实验室创建了敲除小鼠 (PKGI¿cKO)，我们还将从 PKGI 中分离出心肌细胞 (CM)。 cKO 小鼠探索 PKGI 的细胞机制在 SA2 中，我们将探讨 PKGI 的反应。 cKO 小鼠对 TAC 诱导的 LV 压力超负荷，并将测试 CM 特异性 PKGI 的程度？缺失消除了磷酸二酯酶 5 抑制剂西地那非的抗重构作用。在 SA3 中，我们将探索全身 MLK3 敲除小鼠 (MLK​​3-/-) 的心脏重构反应，以测试 PKGI 的临床相关假设。 -相互作用蛋白 MLK3 抑制体内衰老相关重塑。这些拟议的研究将确定 PKGI 的具体机制。该项目非常重要，因为它直接解决了老年人中非常普遍的问题，并且直接测试了新的治疗靶点。 之所以具有创新性，是因为它使用了独特的体内模型，还因为它采用了探索 CM 特异性心脏重塑调节因子的创新策略，这可以转化为新颖的 CM 特异性治疗方法。 公众健康相关性：在老年人中，充血性心力衰竭是发病和死亡的主要原因，与年轻患者相比，老年患者的预后较差。我们提出的项目研究称心力衰竭。心脏重塑，试图寻找老年人心力衰竭的新治疗策略 该项目基于大量新数据，并提出研究可能对限制心脏重塑过程具有直接重要性的途径。该项目的目标是。了解这种新途径（称为 PKGI 途径）在身体特定细胞（称为心肌细胞）中的作用。这项工作的最终希望是通过展示 PKGI 是如何发挥作用的。在心肌细胞中起作用，它可能会建议利用 PKGI 的新医学治疗方法。这些细胞的活性，这与老年患者尤其相关。