The role of adrenergic signaling in cancer cachexia-associated cardiac remodeling

项目摘要 恶病质是一种破坏性的营养不良状态，由食欲下降的协同作用引起。 增加脂肪和瘦体重的新陈代谢。此外，包括心脏在内的多个器官也会受损。 在这种令人衰弱的情况下。虽然许多慢性疾病，如心力衰竭、肾衰竭和肝硬变， 与恶病质有关，这种情况在胰腺导管腺癌(PDAC)中尤其常见。 我们的实验室和其他人在不同的模型中显示了心脏显著的结构和功能重塑 癌症恶病质。这些心脏适应不良的变化也在化疗--幼稚癌症中观察到。 恶病质患者，限制了可耐受的治疗选择和生活质量。然而，目前还没有 癌症相关患者恶病质的有效治疗及心脏不良重塑的介质 恶病质仍然难以捉摸。 交感神经系统(SNS)负责“战斗或逃跑”的反应，并启动身体 与疾病作斗争。慢性SNS过度活动与恶病质的病理生理有关--使白色脂肪变成褐色 组织和提高基础代谢率。然而，SNS在调节心脏重构中的作用 癌症恶病质尚未得到调查。SNS语气的慢性升高是心脏疾病的一个公认的驱动因素 心力衰竭患者通过直接刺激心脏的病理学。提高对他人的共鸣音调 组织，如骨髓，也通过减少CXCL12的表达来推动心血管病理 骨髓，导致骨髓生成增加和炎性白细胞募集到 心血管系统。使用与PDAC相关的恶病质模型，我发现了一个基因签名，表明 心脏肾上腺素能受体的结构重构和脱敏。这些观察结果是一致的 在心脏上有直接的社交网络过度活动。事实上，使用非选择性肾上腺素能受体阻滞剂进行治疗 能够减轻PDAC恶病质动物心脏组织的损失。此外，我发现增加了 心脏中的中性粒细胞池，伴随着骨髓CXCL12表达的下调。 因此，根据我的初步数据和最近的文献，我假设SNS多动症在 癌症恶病质期间心脏的不良重塑。这个项目建议评估交感神经的作用。 恶病质期间心脏和骨髓的过度活动在驱动心脏重构中的作用。 总的来说，这项工作具有广泛的影响，并直接适用于确定新的治疗靶点 治疗恶病质，提高癌症患者的存活率。实现提案的目标将：1)增强 我们对恶病质诱发心脏重构的根本原因的理解，2)提供了新的治疗靶点 对于恶病质，以及3)描述肾上腺素能信号介导心脏应激的新机制，即 广泛适用于几种慢性病。

Project Summary Cachexia is a devastating state of malnutrition brought about by a synergistic combination of decreased appetite and increased metabolism of fat and lean mass. Furthermore, multiple organs, including the heart, are impaired by this debilitating condition. While many chronic diseases such as heart failure, kidney failure, and cirrhosis are associated with cachexia, this condition is particularly prevalent in pancreatic ductal adenocarcinoma (PDAC). Our lab and others demonstrated significant structural and functional remodeling of the heart in various models of cancer cachexia. These maladaptive changes in the heart are also observed in chemotherapy-naïve cancer cachexia patients, limiting tolerable therapeutic options and quality of life. However, there are currently no effective treatments for cachexia and the mediators of adverse cardiac remodeling in cancer-associated cachexia remain elusive. The sympathetic nervous system (SNS) is responsible for the “fight-or-flight” response and primes the body to fight disease. Chronic SNS overactivity is implicated in cachexia pathophysiology by browning white adipose tissue and increasing basal metabolic rate. However, the role of the SNS in regulating cardiac remodeling during cancer cachexia has not been investigated. Chronic elevation in SNS tone is a well-established driver of cardiac pathology in patients with heart failure by direct stimulation of the heart. Elevated sympathetic tone to other tissues, such as the bone marrow, also drives cardiovascular pathology by decreasing Cxcl12 expression in bone marrow, resulting in augmented myelopoiesis and recruitment of inflammatory leukocytes to the cardiovascular system. Using a model of PDAC-associated cachexia, I found a gene signature indicating adverse structural remodeling and desensitization of adrenergic receptors in the heart. These observations are consistent with direct SNS hyperactivity on the heart. Indeed, treatment with a non-selective adrenergic receptor blocker was able to attenuate loss of cardiac tissue in animals with PDAC cachexia. Furthermore, I found increased pool of neutrophils in the heart, which was accompanied by a downregulation of bone marrow Cxcl12 expression. Therefore, based on my preliminary data and recent literature, I hypothesize that SNS hyperactivity mediates adverse cardiac remodeling during cancer-cachexia. This project proposes to assess the effects of sympathetic hyperactivity to the heart as well as bone marrow in driving cardiac remodeling during cachexia. Collectively, this work has broad implications and is directly applicable to identifying new therapeutic targets for treating cachexia and increasing survival in cancer patients. Achieving the goals of the proposal will: 1) enhance our understanding of the root cause of cachexia induced cardiac remodeling, 2) provide novel therapeutic targets for cachexia, and 3) describe novel mechanisms by which adrenergic signaling mediates cardiac stress that is broadly applicable to several chronic diseases.