Role of endothelial cell senescence in age-related cardiomyopathy

内皮细胞衰老在年龄相关性心肌病中的作用

• 批准号: 10726050
• 负责人: Xiaohui Wang
• 金额: $ 22.5万
• 依托单位: EAST TENNESSEE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10726050
• 关键词: ATF6 gene; Acetyl Coenzyme A; Address; Adult; Age; Aging; Astrocytes; Biogenesis; Cardiac; Cardiac Myocytes; Cardiomyopathies; Cardiovascular Diseases; Cardiovascular system; Cause of Death; Cell Aging; Cell Cycle Arrest; Cell Senescence Induction; Cessation of life; Conditioned Culture Media; Data; Development; Disease; Endothelial Cells; Endothelium; Enzymes; Etoposide; Exhibits; Fibroblasts; Fibrosis; Functional disorder; Gender; Gene Expression; Genes; Genetic Transcription; Glucose; Glycolysis; Heart Hypertrophy; Heart failure; Homeostasis; Hypertrophy; Immune; Impairment; Inflammation; Innovative Therapy; Maintenance; Mediating; Metabolic; Metabolic Diseases; Mitochondria; Mitochondrial DNA; Mus; Myocardial; Myocardial dysfunction; Patients; Phenotype; Phosphorylation; Play; Production; Pyruvate; Regulation; Role; Signal Transduction; Tissues; Transcriptional Activation; age related; blood glucose regulation; cardiovascular risk factor; factor A; human old age (65+); mtTF1 transcription factor; neurotrophic factor; novel; oxidation; prevent; protective effect; protein folding; pyruvate dehydrogenase kinase 4; senescence; transcription factor

Abstract Age is a major risk factor for cardiovascular associated diseases which are leading causes of death globally. Accordingly, 80% of all cardiovascular deaths occurred in patients aged 65 and over. Endothelial cell senescence, characterized by cell cycle arrest and a senescence-associated secretory phenotype (SASP), is a major contributor to age related cardiovascular dysfunction. However, the mechanism by which endothelial cells are subjected to senescence is still unclear. We have recently made novel findings that endothelial cell HSPA12B deficient (eHSPA12B-/-) mice exhibit cardiac endothelial cell senescence accompanied by severe cardiac hypertrophy, fibrosis, and persistent inflammation when compared with age- and gender-matched WT controls. Our findings suggest that senescent endothelial cells play an important role in the regulation of cardiac hypertrophy and fibroblast activation and that endothelial cell HSPA12B limits senescence of endothelial cells. Therefore, understanding the mechanisms by which HSPA12B regulates endothelial cell senescence would be important for seeking an approach to prevent or reverse senescent endothelial cells, thus reducing age-related cardiovascular disease. To elucidate how HSPA12B limits senescence of endothelial cells, we examined the effect of HSPA12B on ATF6 (Activating transcription factor 6) transcriptional activity and its target gene MANF (Mesencephalic Astrocyte Derived Neurotrophic Factor) expression. ATF6 is an important transcriptional factor that regulates the expression of genes involved in proper protein folding and cellular senescence. MANF is an evolutionarily conserved protective modulator for the maintenance of tissue immune and metabolic homeostasis. Interestingly, we observed that HSPA12B is critical for sustaining ATF6 transcriptional activity and MANF expression. The data suggest that ATF6 and MANF may be involved in the HSPA12B mediated protective effect on endothelial cell senescence. To investigate how endothelial cell senescence contributes to cardiac hypertrophy, we examined cardiac mitochondrial glucose oxidation (MGO) which is one of the major contributors to myocardial energy production. Compromised mitochondrial glucose oxidation leads to the development of cardiac hypertrophy and eventually heart failure. We observed that eHSPA12B-/- resulted in decreased Acetyl-CoA and increased lactate accumulation. The data indicate that eHSPA12B-/- impairs cardiac mitochondrial glucose oxidation. Our observation also suggests that senescent endothelial cells induce cardiac hypertrophy via impairment of cardiac myocyte MGO (mitochondrial glucose oxidation). To address how endothelial cell senescence impairs cardiac MGO, we induced endothelial cell senescence by ETO (etoposide), collected the medium as the senescent conditioned medium (SCM), and treated adult cardiac myocytes with the SCM. We observed that SCM promotes metabolic reprogramming from glucose oxidation to glycolysis in adult cardiac myocytes by increasing PDK4 (Pyruvate Dehydrogenase Kinase 4) and decreasing TFAM (Mitochondrial transcription factor A). PDK4 is a key enzyme in the regulation of glucose oxidation by inhibiting the conversion of pyruvate into Acetyl-CoA via promoting PDH phosphorylation and inactivation. TFAM is a core mitochondrial transcription factor for mitochondrial biogenesis by regulating mtDNA replication and transcription. This application is to decipher the role of HSPA12B in age-related endothelial cell senescence and how endothelial cell senescence results in cardiac hypertrophy and dysfunction. Based on our novel findings, we hypothesize that: i) HSPA12B limits endothelial cell senescence is mediated by activation of ATF6/MANF signaling and that; ii) endothelial cell senescence contributes to cardiac hypertrophy and dysfunction via impaired mitochondrial glucose oxidation in cardiomyocytes. To critically evaluate this hypothesis, we propose the following specific aims. Aim 1. Define the mechanisms by which HSPA12B regulates ATF6 transcriptional activity and limits endothelial cell senescence. Aim 2. Investigate the role of endothelial cell senescence in age-related cardiac hypertrophy and its underlying mechanisms. Successful completion of the proposed studies will result in a wealth of novel data showing the novel role of HSPA12B mediated ATF6 in the regulation of endothelial cell senescence. The senescent endothelial cells contribute to age-related cardiac metabolic disorders and hypertrophy. These new findings will be the basis for the development of innovative therapies for age-related cardiomyopathy.

摘要 年龄是心血管相关疾病的主要危险因素，而心血管相关疾病是导致死亡的主要原因 在全球因此，80%的心血管死亡发生在65岁及以上的患者中。内皮细胞 衰老，其特征在于细胞周期停滞和衰老相关的分泌表型（SASP），是一种 年龄相关心血管功能障碍的主要原因。然而，内皮细胞 细胞是否会衰老仍不清楚。 我们最近有了新的发现，内皮细胞HSPA 12 B缺陷（eHSPA 12 B-/-）小鼠表现出 心脏内皮细胞衰老伴有严重的心脏肥大、纤维化和持续性 与年龄和性别匹配的WT对照相比，我们的研究结果表明， 内皮细胞在心脏肥大和成纤维细胞活化的调节中起重要作用， 内皮细胞HSPA 12 B限制内皮细胞衰老。因此了解 HSPA 12 B调节内皮细胞衰老的机制对于寻求一种新的抗衰老药物是重要的。 这是一种预防或逆转衰老内皮细胞的方法，从而减少与年龄相关的心血管疾病。 为了阐明HSPA 12 B如何限制内皮细胞的衰老，我们检测了HSPA 12 B对内皮细胞衰老的影响。 ATF 6（激活转录因子6）转录活性及其靶基因MANF（中脑 星形胶质细胞源性神经营养因子）表达。ATF 6是一个重要的转录因子， 参与蛋白质折叠和细胞衰老的基因的表达。MANF是一种进化的 用于维持组织免疫和代谢稳态的保守保护性调节剂。 有趣的是，我们观察到HSPA 12 B对维持ATF 6转录活性和MANF至关重要， 表情提示ATF 6和MANF可能参与了HSPA 12 B介导的细胞保护作用。 对内皮细胞衰老的影响。 为了研究内皮细胞衰老如何导致心肌肥大，我们检测了心脏 线粒体葡萄糖氧化（MGO）是心肌能量产生的主要贡献者之一。 受损的线粒体葡萄糖氧化导致心脏肥大的发展， 心衰我们观察到eHSPA 12 B-/-导致乙酰辅酶A减少和乳酸增加 积累数据表明eHSPA 12 B-/-损害心脏线粒体葡萄糖氧化。我们 观察还表明，衰老的内皮细胞通过损伤 心肌细胞MGO（线粒体葡萄糖氧化）。 为了解决内皮细胞衰老如何损害心脏MGO，我们诱导了内皮细胞衰老， 通过ETO（依托泊苷），收集培养基作为衰老条件培养基（SCM），并处理成人 心肌细胞与SCM。我们观察到SCM促进葡萄糖代谢重编程 通过增加PDK 4（丙酮酸脱氢酶激酶4）和 降低TFAM（线粒体转录因子A）。PDK 4是葡萄糖调节的关键酶 通过促进PDH磷酸化抑制丙酮酸转化为乙酰辅酶A的氧化， 失活TFAM是通过调节线粒体生物发生的核心线粒体转录因子 mtDNA复制和转录。 本申请旨在阐明HSPA 12 B在年龄相关的内皮细胞衰老中的作用，以及如何 内皮细胞衰老导致心脏肥大和功能障碍。根据我们的新发现，我们 假设：i）HSPA 12 B通过激活ATF 6/MANF介导限制内皮细胞衰老 ii）内皮细胞衰老通过以下途径导致心脏肥大和功能障碍： 心肌细胞线粒体葡萄糖氧化受损。为了批判性地评估这一假设，我们建议 以下具体目标。目标1.定义HSPA 12 B调节ATF 6转录的机制 活性和限制内皮细胞衰老。目标2.研究内皮细胞衰老在 年龄相关性心肌肥大及其潜在机制。 成功完成拟议的研究将产生丰富的新数据，显示新的作用 HSPA 12 B介导的ATF 6在内皮细胞衰老调控中的作用衰老内皮细胞 导致与年龄相关的心脏代谢紊乱和肥大。这些新的发现将成为 年龄相关性心肌病的创新疗法的发展。