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

"DNA methylation patterns are frequently perturbed in human diseases such as imprinting disorders and cancer. In cancer increased aberrant DNA methylation is believed to work as a silencing mechanism for tumor suppressor genes such as INK4A, RB1 and MLH1. The high frequency of abnormal DNA methylation found in cancer might be due to the inactivation of a proofreading and/or fidelity system regulating the correct patterns of DNA methylation. Currently we have very limited knowledge about such mechanisms. In this research proposal, we will focus on elucidating the biological function of a novel protein family, which catalyzes the conversion of 5-methyl-cytosine (5-mC) to 5-hydroxymethyl cytosine (5-hmC). By catalyzing this reaction the TET proteins most likely work as DNA demethylases, and they might therefore have a role in regulating DNA methylation fidelity. Interestingly, accumulated data has in the last 2 years shown that TET2 is one of the most frequently mutated genes in various hematological cancers. We propose to investigate the molecular mechanisms by which TET2 regulates normal hematopoiesis, how its inactivation leads to hematopoietic malignancies and how the protein contributes to the regulation of DNA methylation patterns and transcription. Furthermore, we propose several experimental approaches for identifying proteins required for the recruitment of TET proteins to target genes and to analyze their role in the regulation of DNA methylation patterns and in cancer. Finally, we will investigate the potential functional role of 5-hmC and explore the potential mechanisms by which this modification could be erased. We expect to provide new insights into the biology of DNA methylation, hydroxymethylation and contribute to unravel the roles of TET proteins in normal physiology and cancer."

2 298 000 €

Start date: 2012-07-01, End date: 2017-06-30

Maintaining oxygen homeostasis is an essential requirement for all metazoa. Oxygen is required for efficient generation of energy, however, as oxygen levels decrease (hypoxia), cells mount a variety of adaptive responses. Each cell in the body can sense and respond to hypoxia, yet the molecular mechanisms that regulate these responses are only beginning to be delineated. Hypoxia plays crucial roles in the pathophysiology of cancer, neurological dysfunction, myocardial infarction and lung disease. Therefore, the goal of the proposed research is to better understand how cells sense and adapt to hypoxia. To this end, I am using the powerful genetic model of Caenorhabditis elegans to identify novel molecular mechanisms required for oxygen homeostatic responses. A critical regulator of hypoxic responses in all cell types is the conserved hypoxia-inducible factor (HIF-1). In response to a hypoxic insult, HIF-1 transcriptionally regulates a wide variety of target genes to facilitate adaptation. Recent studies indicate that in addition to the canonical HIF-1 pathway, microRNAs (miRNAs) play important roles in hypoxic response mechanisms. miRNAs are regulatory molecules that predominantly repress protein production of their target genes, however, their roles in hypoxic adaptation are poorly understood. I recently found that specific phylogenetically conserved miRNAs are regulated by hypoxia in C. elegans; and that the function of these miRNAs is required for survival of animals in low oxygen conditions. This is truly an emerging field of science and I expect to make groundbreaking discoveries in the regulation of hypoxic and metabolic responses by miRNAs, which will improve our understanding of many disease processes. The proposed research will 1) analyze the functional roles of specific miRNAs in hypoxic responses and 2) utilize immunoprecipitation, bioinformatics and genetic screening combined with state-of-the-art deep sequencing technology to identify novel miRNA targets required for adaptation to hypoxia.

1 478 508 €

Start date: 2010-11-01, End date: 2015-10-31

The ribotoxic stress response (RSR) surveys the structural and functional integrity of ribosomes and is triggered by diverse groups of ribotoxins (e.g. ricin), UV irradiation and some chemotherapeutics. When presented with impaired ribosomes, the proximal MAPKKK ZAK activates MAP kinases p38 and JNK to initiate a powerful inflammatory response. This signalling contributes to the detrimental reactions to ribotoxins and fatal side effects of cancer therapy. However, despite decades of research into the RSR, the physiological relevance of the underlying pathway in whole organisms is unknown. I hypothesize that the RSR constitutes a general translation quality control pathway and hence I aim to uncover the physiological and pathological implications of RSR impairment in mice and nematodes. In one line of investigation, I will elucidate the connections between UV radiation and RSR-mediated p38 activation. I hypothesize that this signalling pathway is critical for sunlight-induced skin inflammation and development of skin cancers of different cellular origins. Rewardingly, we found that cells from our ZAK knockout (KO) mice are refractory to UV-induced p38 activation, which is a significant contributor to skin cancer development. My team has also observed deregulation of protein translation in RSR-deficient human and mouse cells, and a reduced lifespan of ZAK KO nematodes. Thus encouraged, I will determine the impact of the RSR pathway on cancer development and aging processes in mice, and I will unravel the molecular connections between defective ribosomes, RSR activation and regulation of translation. Finally, I am in a unique position to evaluate the RSR as a putative drug target and I will investigate the potential of ZAK inhibition to treat or prevent skin cancer, and to remedy inflammation arising from infection with ribotoxin-producing bacteria. In sum, PHYRIST will yield the first detailed insight into the in vivo relevance of the ribotoxic stress response.

1 997 678 €

Start date: 2020-06-01, End date: 2025-05-31