Adipose tissue ATGL regulates cardiac energy metabolism in heart failure

慢性心力衰竭的发展以交感神经系统的持续过度激活为特征，导致良好的心血管后果。与此同时，频繁的肾上腺素能刺激对脂肪组织代谢产生重要影响，包括显著诱导脂肪组织脂解。我们最近发现，由脂肪甘油三酯脂肪酶（ATGL）介导的脂肪组织脂解直接影响心力衰竭发展过程中的心脏功能，涉及脂肪组织的脂肪酸分泌和循环脂质的变化。抑制脂肪组织ATGL活性可改善左心室功能，可能成为新的治疗靶点。但是，脂肪组织ATGL调节心功能的潜在分子机制尚不完全清楚。本项目拟在前期研究的基础上，探讨脂肪组织ATGL在心力衰竭时控制心功能的机制：(1)心肌能量底物和全身代谢的改变；(2)心肌磷脂组的改变及其对心肌线粒体功能的影响；(3)心脏炎症的调节及其与线粒体功能的联系。为了实现这些目标，我们将研究诱导脂肪组织特异性atgl缺陷（Atgl-fl/fl-Adipoq-cre/ERT2）小鼠遭受两种不同的心力衰竭模型：横断主动脉收缩和β -肾上腺素能激动剂异丙肾上腺素的长时间刺激。小鼠将进行全面的心脏表型分析，包括斑点跟踪超声心动图。为了评估(1)心脏能量代谢，我们将对左心室组织样本进行心脏PET分析以及基于ms的代谢组学和脂质组学分析。为了确定心肌线粒体功能与脂肪组织ATGL的心脏保护作用的相关性，我们将通过MS-based线粒体脂质组学在分离线粒体中研究线粒体脂质组成和功能，并使用海马技术在我们的模型中分离的原代心肌细胞中分析线粒体呼吸。最后，我们的初步数据指向(3)通过脂肪组织ATGL改变心脏炎症细胞浸润。为了进一步阐明这一过程，我们将通过流式细胞术分析上述模型中的心脏单细胞悬浮液进行免疫细胞表型分析。最后，我们将通过研究线粒体DNA在自溶酶体中的积累，以及随后心肌细胞中TLR-9信号的激活，将心脏炎症反应与线粒体功能障碍联系起来。总之，本研究旨在准确确定慢性心力衰竭中脂肪组织atgl抑制的心脏保护作用的潜在机制。这些数据将有助于开发一种新的基于atgl的治疗慢性心力衰竭的药理学方法。

The development of chronic heart failure is characterized by a persistent over-activation of the sympathetic nervous system resulting in the well described cardiovascular consequences. In parallel, frequent adrenergic stimulation exerts crucial effects on adipose tissue metabolism, including a marked induction of adipose tissue lipolysis. We could recently show that adipose tissue lipolysis mediated by the adipose triglyceride lipase (ATGL) directly affectscardiac function during heart failure development involving fatty acid secretion from adipose tissue and changes of circulating lipids. The inhibition of adipose tissue ATGL activity resulted in an improvement of left ventricular function, and may serve as a new therapeutic target. But, the underlying molecular mechanisms by which adipose tissue ATGL regulates cardiac function are incompletely understood. Based on previous data this project aims to investigate the following mechanisms by which adipose tissue ATGL controls cardiac function in heart failure: (1) changes in cardiac energy substrate and systemic metabolism, (2) cardiac phospholipidome changes and the impact on cardiac mitochondrial function, and (3) regulation of cardiac inflammation and its link to mitochondrial function. To achieve these aims we will studyinducible adipose tissue-specific ATGL-deficient (Atgl-fl/fl-Adipoq-cre/ERT2) mice subjected to two different models of heart failure: transverse aortic constriction and prolonged stimulation with the betaadrenergic agonist isoproterenol. Mice will undergo comprehensivecardiac phenotyping including speckle-tracking echocardiography. To assess (1) cardiac energy metabolism we will perform cardiac PET analysis as well as MS-based metabolomics and lipidomics Analysis from left ventricular tissue samples. To determine (2) the relevance of cardiac mitochondrial function for adipose tissue ATGL´s cardioprotective actions, mitochondrial lipid composition and function will be investigated by MS-based mitochondrial lipidomics in isolatedmitochondria and analysis of mitochondrial respiration using the Seahorse technology in isolated primary cardiomyocytes from our models. Finally, our preliminary data points towards a (3) modification of cardiac inflammatory cell infiltration through adipose tissue ATGL.To further clarify this process we will perform an immune cell phenotyping by flow cytometry analysis of cardiac single cell suspensions in the above mentioned models. Finally, we will link the cardiac inflammatory response to mitochondrial dysfunction by investigating the accumulation of mitochondrial DNA in autolysosomes, and a subsequent activation of TLR-9 signaling in cardiomyocytes. In summary, the present study aims to exactly determine the underlying mechanisms of the cardioprotective Actions of adipose tissue ATGL-inhibition in chronic heart failure. These data will help to develop a new ATGL-based pharmacological approach for the treatment of chronic heart failure.