Mathematical modeling of the metabolic implications of the diabetic heart

糖尿病心脏代谢影响的数学模型

• 批准号: 422215721
• 负责人: Privatdozent Dr. Nikolaus Berndt
• 金额: --
• 依托单位: Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke (DIfE)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/422215721?language=en
• 关键词: Mathematical; modeling; metabolic; implications; diabetic

Cardiac metabolism needs to adapt to short-term and long-term variations in oxygen and nutrient supply and energy demand to ensure sufficient ATP supply for proper cardiac function. While short term adaptation is the result of kinetic regulation of metabolic enzymes by substrate availability, allosteric regulation and hormonal regulation of interconvertible enzymes, long term adaptation proceed by alterations of the metabolic capacity and the regulatory signaling pathways by gene expression. Especially Diabetes Mellitus Typ 2 (DMT2) is characterized by alterations in the blood plasma nutrient and hormone composition resulting in cardiac remodeling. Additional, alterations in ATP demanding processes (AP generation, heart power) and alterations in the cardiac vascularization can be observed. The associated adaptive processes can result in mitochondrial dysfunction, ATP deficiency and impaired cardiac functionality thereby contributing significantly to cardiac dysfunction and heart failure. The aim of this project is to develop a comprehensive kinetic model of the central metabolism of cardiomyocytes (carbohydrate metabolism, fatty acid metabolism, amino acid metabolism) and radical detoxification, including short term regulation of enzyme activities by variations of substrate concentrations, hormone-dependent reversible phosphorylation and allosteric regulation as well as long term adaptive changes in enzyme abundances (gene expression). Modeling will be based on a kinetic approach. Each enzymatic step will be described by an appropriate rate law. Enzymatic rate laws will be derived from the biochemistry literature compiled during the last six decades. We will use the model to predict the metabolic state of cardiomyocytes (metabolite concentrations, flux distributions, nutrient exchange, etc.) under different external and internal conditions. We will use protein abundance data obtained from diabetic animals during different disease stages for scaling of the metabolic processes. We will validate the model by measurements of metabolite concentrations, proteins and phosphorylated proteins. Phosphorylated proteins will be determined by immunoblotting, metabolites will be analyzed by HPLC or by using commercial kits for individual metabolites. In the case such kits are not-available or not applicable an HPLC/HPLC-MS method application will be established. Furthermore, mitochondrial function (O2 consumption rate) will be assessed by XF instrumentation (Seahorse Bioscience). Relevant exchange fluxes between cells and the external space will be measured by time-dependent detection of metabolites using LC-MS/MS. Additionally fluorescence microscopy and confocal-laser scanning microscope for the determination of intracellular states such as NAD(P)H redox state and multiphoton microscopy for the determination of cardiac vascularization will be used. Alterations in cardiac action potentials will be assessed juxtacellular recordings in vivo.

心脏代谢需要适应氧、营养供应和能量需求的短期和长期变化，以确保有足够的ATP供应以维持正常的心脏功能。短期适应是代谢酶通过底物可获得性、变构调节和激素调节相互转化酶的动态调节的结果，而长期适应是通过基因表达改变代谢能力和调节信号通路而进行的。尤其是2型糖尿病(DMT2)，其特征是血浆营养成分和激素成分发生改变，导致心脏重构。此外，可以观察到ATP需求过程(AP生成、心力)和心脏血管形成的变化。相关的适应过程可导致线粒体功能障碍、ATP缺乏和心脏功能受损，从而显著导致心脏功能障碍和心力衰竭。本项目的目的是建立心肌细胞中枢代谢(碳水化合物代谢、脂肪酸代谢、氨基酸代谢)和自由基解毒的综合动力学模型，包括底物浓度变化对酶活性的短期调节、激素依赖的可逆磷酸化和变构调节以及酶丰度(基因表达)的长期适应性变化。建模将基于动力学方法。每一个酶的步骤将由一个适当的速率定律来描述。酶速率定律将从过去60年汇编的生物化学文献中推导出来。我们将使用该模型来预测心肌细胞的代谢状态(代谢物浓度、流量分布、营养交换等)。在不同的外部和内部条件下。我们将使用糖尿病动物在不同疾病阶段获得的蛋白质丰度数据来衡量代谢过程。我们将通过测量代谢物浓度、蛋白质和磷酸化蛋白质来验证模型。磷酸化的蛋白质将通过免疫印迹法确定，代谢物将通过高效液相色谱法或使用商业试剂盒进行单独代谢物的分析。在此类试剂盒无法获得或不适用的情况下，将建立高效液相色谱/高效液相色谱-质谱仪方法应用程序。此外，线粒体功能(耗氧率)将通过XF仪器(海马生物科学)进行评估。细胞与外部空间之间的相关交换通量将通过LC-MS/MS对代谢物的时间相关检测来测量。此外，还将使用荧光显微镜和激光共聚焦扫描显微镜来确定细胞内的状态，如NAD(P)H氧化还原状态，以及使用多光子显微镜来确定心脏血管的形成。心脏动作电位的改变将在活体细胞旁记录中进行评估。