ERC FUNDED PROJECTS

Gastric bypass surgery results in massive weight loss and diabetes remission. The effect is superior to intensive medical treatment, showing that there are mechanisms within the body that can cure diabetes and obesity. Revealing the nature of these mechanisms could lead to new, cost-efficient, similarly effective, non-invasive treatments of these conditions. The hypothesis is that hyper-secretion of a number of gut hormones mediates the effect of surgery, as indicated by a series of our recent studies, demonstrating that hypersecretion of GLP-1, a hormone discovered in my laboratory and basis for the antidiabetic medication of millions of patients, is essential for the improved insulin secretion and glucose tolerance. But what are the mechanisms behind the up to 30-fold elevations in secretion of these hormones following surgery? Constantly with a translational scope, all elements involved in these responses will be addressed in this project, from detailed analysis of food items responsible for hormone secretion, to identification of the responsible regions of the gut, and to the molecular mechanisms leading to hypersecretion. Novel approaches for studies of human gut hormone secreting cells, including specific expression analysis, are combined with our advanced and unique isolated perfused gut preparations, the only tool that can provide physiologically relevant results with a translational potential regarding regulation of hormone secretion in the gut. This will lead to further groundbreaking experimental attempts to mimic and engage the identified mechanisms, creating similar hypersecretion and obtaining similar improvements as the operations in patients with obesity and diabetes. Based on our profound knowledge of gut hormone biology accumulated through decades of intensive and successful research and our successful elucidation of the antidiabetic actions of gastric bypass surgery, we are in a unique position to reach this ambitious goal.

2 500 000 €

Start date: 2017-01-01, End date: 2021-12-31

Despite educational, political and biomedical research efforts, obesity, type 2 diabetes and related metabolic diseases are increasing worldwide at an alarming rate. Failure to deliver efficient and safe medical therapies is a result of our incomplete understanding of the pathogenesis of the metabolic syndrome. Current knowledge implicates impaired CNS control over appetite, body weight and systemic metabolism as a key pathogenic process leading to obesity and type 2 diabetes. Yet, years of intense study focused on neuronal signalling have produced no transformative breakthroughs. Control centers located in the hypothalamic arcuate nucleus (ARC) serve as primary targets of afferent hormone signals regulating systemic control of body weight and metabolism and appear to be most affected by high fat high sugar (HFHS) diets. Recently, we discovered that in the early stages of the metabolic syndrome induced by consumption of a HFHS diet, significant changes beyond neuronal pathologies occur in hypothalamic nuclei responsible for metabolic control, such as the ARC. Specifically, we observe in hypothalami of mice, rats and humans increased reactive microgliosis and astrocytosis as well as a decline in regulatory T-cell presence. We hypothesize that hypothalamic inflammatory processes triggered by hypercaloric environments impair hormone sensing, disrupt glial homeostasis and incapacitate these hypothalamic control centers, ultimately contributing to development of obesity and diabetes. Building on a considerable body of preliminary data, we will apply an array of advanced technologies to A) develop a functional understanding of the pathophysiology of diet-induced hypothalamic inflammation, B) test if hypothalamic inflammation plays a critical role in the development of the metabolic syndrome, and C) attempt to target these novel pathogenic processes for the first time using novel targeted therapeutic approaches.

2 402 280 €

Start date: 2016-09-01, End date: 2022-08-31

Arterial hypertension is a major cardiovascular risk factor that affects between 10-40% of the population. Primary aldosteronism (PA) due to adrenal excess production of aldosterone is the most common secondary form of hypertension affecting 4-12% of hypertensives. Given the severe cardiovascular adverse effects of aldosterone excess early detection and individualized treatment of PA has important impact on clinical outcome and survival. However, the pathophysiology of PA is not well understood: While we recently identified specific genes underlying aldosterone producing adenoma, the most prevalent form of PA, bilateral adrenal hyperplasia, has remained enigmatic. It is the first hypothesis of this proposal that the pathophysiology of PA is a process based on two ‘hits’: agonistic angiotensin II type 1 receptor (AT1R) autoantibodies (proliferation, nodular hyperplasia) and somatic mutations (adenoma formation). It is the second hypothesis, that together, both factors induce not only aldosterone but also marked glucocorticoid excess. 1.) I will analyze prevalence and binding characteristics of AT1R autoantibodies as a pathophysiologic basis of PA. 2.) I will determine the effect of AT1R antibodies and genetic factors on cellular adrenal cortex models in vitro. 3.) I will extend these studies to specific in vivo genetic rodent models of PA. 4.) I will quantify aldosterone and glucocorticoid excess as disease effectors of AT1R autoantibodies and somatic mutations using liquid chromatography–mass spectrometry in PA. 5.) Using the generated data I will develop a pathophysiology-based concept of PA. This groundbreaking approach using innovative in vitro and in vivo models, state-of-the art genetic, immunologic and steroidobolomic techniques will uniquely open new avenues to the pathophysiologic understanding of PA. It will change our current understanding of PA, has high health impact and, thus, will pave the way to novel concepts of aldosterone excess and hypertension.

2 496 875 €

Start date: 2017-01-01, End date: 2022-12-31

Cardiovascular disease including coronary heart disease remains the leading cause of death worldwide. Atherosclerosis as the underlying pathology is a lipid-driven inflammatory disease of arteries giving rise to vulnerable lesions prone to rupture and thrombotic occlusion. Lesions develop at predilection sites with disturbed flow, where endothelial damage promotes intimal retention of lipoproteins and inflammatory leukocyte recruitment. Past research has largely focused on atherogenic factors and their inhibition but not on boosting a counterbalance by protective mechanisms. We have recently found that the CXCL12/CXCR4 chemokine-receptor axis protects against atherosclerosis by controlling neutrophil homeostasis and facilitating endothelial regeneration in mice. This is supported by genome-wide association studies, identifying genetic variants near CXCL12 associated with the risk of coronary heart disease. The protective regulation of endothelial repair by microRNAs also involves CXCL12/CXCR4. However, the causal and cell-specific impact of this axis remains unclear. To balance the ongoing expansion of genetic risk variants, PROVASC aims to discover/elucidate novel mechanisms for protective cell homeostasis and regeneration counteracting atherosclerosis in depth. To this end, we will dissect cell-specific effects of the CXCR4-CXCL12 axis using an array of mouse lines for conditional deletion and bone marrow chimeras to compare resident versus hemato-poietic cell compartments. We will validate a role of coding and non-coding genetic risk variants affecting CXCL12/CXCR4 in different cell types and humanized mouse models. By identifying relevant microRNAs targeting CXCL12/CXCR4, we will unravel a regulation of this axis by cell type-specific microRNAs. Given the ubiquitous relevance of CXCL12/CXCR4, we expect that the impact of such new mechanisms will extend to other chronic inflammatory diseases, allowing for tailored strategies of tissue protection and regeneration.

2 498 250 €

Start date: 2016-10-01, End date: 2022-09-30