Studies on the mechanisms of glucolipotoxicity in human beta cells in the context of type 2 diabetes mellitus

糖尿病是世界范围内最常见的疾病之一，发病率呈快速上升趋势。超过90%的患者患有2型糖尿病。肥胖在发病机制中尤为重要，这是西式饮食中碳水化合物和高脂肪食物成分过多的结果。随后的胰岛素抵抗通过糖耐量的逐渐恶化导致分泌胰岛素的β细胞功能障碍和逐步丧失，从而导致高血糖和血浆游离脂肪酸水平升高。这些现象也称为糖毒性和脂毒性。活性氧自由基(超氧阴离子自由基、过氧化氢、羟基自由基)介导了这种毒性，这种毒性产生于脂肪酸和葡萄糖的新陈代谢。糖脂毒性这一术语结合了这两种现象，是本项目的重点。尽管引起了极大的科学兴趣，但其潜在的机制还没有完全被理解。为此，在计划的项目中，分析脂肪酸的结构-毒性关系并结合葡萄糖浓度的增加是主要的概念工具，这已被证明对阐明潜在的病理机制特别有帮助。这项研究将在人类endo-βH1β细胞以及患有和不患有2型糖尿病的患者的初级胰岛上进行。选择这一焦点是为了给患者创造最佳的翻译条件。该项目确定了三个主要目标。1)进行脂肪酸和葡萄糖暴露后的比较基因组分析。2)利用RT-qPCR验证感兴趣的靶基因，特别注意糖毒性和脂毒性之间的相互作用。3)在最后一步中，将产生转基因的人EnDoc-βH1β细胞，以获得对深入机制的深入了解。为此目的，各种亚细胞器(线粒体、过氧化物体、内质网)对糖脂毒性的重要性将使用与介质形成有关的广泛方法来阐明，特别是有毒的活性氧物种。这些计划中的研究的目的是促进对糖脂毒性潜在的分子机制的理解，从而能够呈现出毒性机制及其信号通路的完整图景。这将为建立新的干预措施开辟新的前景。这些可能是预防性的生活方式措施，特别是关于健康饮食，但也是新的药物治疗方法，旨在通过恢复正常的β细胞功能来改善2型糖尿病代谢状态中受损的糖耐量。

Diabetes mellitus is one of the most prevalent diseases worldwide with a rapidly increasing incidence. More than 90% of patients suffer from type 2 diabetes. Obesity is of particular importance in the pathogenesis, a consequence of Western style diet with an excess of carbohydrate and high-fat food constituents. Subsequent insulin resistance results in dysfunction and stepwise loss of insulin-secreting beta cells through gradual deterioration of glucose tolerance, thereby causing hyperglycaemia and increased plasma free fatty acid levels. These phenomena are also known as glucotoxicity and lipotoxicity. Reactive oxygen species (superoxide radicals, hydrogen peroxide, hydroxyl radicals) mediate this toxicity, which arise in the metabolism of fatty acids and glucose. The term glucolipotoxicity combines both phenomena and is in the focus of this project. Despite the great scientific interest, the underlying mechanisms are not fully understood. For this purpose, in the planned project, the analysis of the structure-toxicity relationships of fatty acids in combination with increased glucose concentrations is the main conceptual tool to be used, which has proven to be particularly helpful in the elucidation of the underlying pathomechanisms. The studies will be performed on human EndoC-βH1 beta cells and in primary islets of patients with and without type 2 diabetes. This focus has been chosen to create optimal conditions for translation to the patient. Three main goals have been defined for this project. 1) Comparative genome analyses after fatty acid and glucose exposure are to be carried out. 2) Verification of interesting target genes using RT-qPCR with special attention to the interactions between glucotoxicity and lipotoxicity. 3) In a final step, genetically modified human EndoC-βH1 beta cells are to be generated to gain a deeper insight in the in-depth mechanistic understanding. For this purpose the importance of the various subcellular organelles (mitochondria, peroxisomes, endoplasmic reticulum) for glucolipotoxicity will be elucidated using a broad range of methods with regard to the formation of mediators, in particular toxic reactive oxygen species. The intention of these planned studies is to advance the understanding of the molecular mechanisms underlying glucolipotoxicity to the extent that a complete picture of the mechanisms of toxicity and their signaling pathways can be presented. This should open up perspectives for the establishment of new interventional measures. These may be preventative lifestyle measures, specifically with respect to a healthy diet, but also new pharmaco-therapeutic approaches aiming at an improvement of the impaired glucose tolerance in the type 2 diabetic metabolic state by restoring normal beta cell function.