ERC FUNDED PROJECTS

Obesity and diabetes have reached pandemic proportions and new therapeutic strategies are critically needed. Brown adipose tissue (BAT), a major source of heat production, possesses significant energy-dissipating capacity and therefore represents a promising target to use in combating these diseases. Recently, I discovered a novel link between circadian rhythm and thermogenic stress in the control of the conserved, calorie-burning functions of BAT. Circadian and thermogenic signaling to BAT incorporates blood-borne hormonal and nutrient cues with direct neuronal input. Yet how these responses coordinately shape BAT energy-expending potential through the regulation of cell surface receptors, metabolic enzymes, and transcriptional effectors is still not understood. My primary goal is to investigate this previously unappreciated network of crosstalk that allows mammals to effectively orchestrate daily rhythms in BAT metabolism, while maintaining their ability to adapt to abrupt changes in energy demand. My group will address this question using gain and loss-of-function in vitro and in vivo studies, newly-generated mouse models, customized physiological phenotyping, and cutting-edge advances in next generation RNA sequencing and mass spectrometry. Preliminary, small-scale validations of our methodologies have already yielded a number of novel candidates that may drive key facets of BAT metabolism. Additionally, we will extend our circadian and thermogenic studies into humans to evaluate the translational potential. Our results will advance the fundamental understanding of how daily oscillations in bioenergetic networks establish a framework for the anticipation of and adaptation to environmental challenges. Importantly, we expect that these mechanistic insights will reveal pharmacological targets through which we can unlock evolutionary constraints and harness the energy-expending potential of BAT for the prevention and treatment of obesity and diabetes.

1 497 008 €

Start date: 2015-05-01, End date: 2020-04-30

"The attine fungus-growing ants are prime models for understanding phenotypic adaptations in social evolution and symbiosis. The mutualism has many hallmarks of advanced cooperation in its mating system commitments and functional complementarity between multiple symbiont partners, but potential conflicts between sexes and castes over reproductive priorities, and between hosts and symbionts over symbiont mixing have also been documented. With collaborators at BGI-Shenzhen and the Smithsonian Institution my group has obtained six reference genomes representing all genus-level branches of the higher attine ants and a lower attine outgroup. With collaborators in Denmark and Australia we have pioneered proteomic approaches to understand the preservation of sperm viability in spite of sperm competition and the enzymatic decomposition of plant substrates that the ants use to make their fungus gardens grow. Here, I propose an integrated study focusing on four major areas of attine ant biology that are particularly inviting for in depth molecular approaches: 1. The protein-level networks that secure life-time (up to 20 years) sperm storage in specialized ant-queen organs and the genetic mechanisms that shape and adjust these “sexual symbiome” networks. 2. The ant-fungal symbiome, i.e. the dynamics of fungal enzyme production for plant substrate degradation and the redistribution of these enzymes in fungus gardens through fecal deposition after they are ingested but not digested by the ants. 3. The microbial symbiome of ant guts and other tissues with obligate bacterial mutualists, of which we have identified some and will characterize a wider collection across the different branches of the attine ant phylogeny. 4. The genome-wide frequency of genomic imprinting and the significance of these imprints for the expression of caste phenotypes and the regulation of potential reproductive conflicts."

2 290 102 €

Start date: 2013-05-01, End date: 2018-04-30

The global epidemics of obesity and diabetes type 2 lead to higher abundancy of medical conditions like non-alcoholic fatty liver disease causing an increase in liver failure and demand for liver transplants. The shortage of donor organs and the insufficient success in tissue engineering to ex vivo grow complex organs like the liver is a global medical challenge. ArtHep targets the assembly of hepatic-like tissue, consisting of biological and synthetic entities, mimicking the core structure elements and key functions of the liver. ArtHep comprises an entirely new concept in liver regeneration with multi-angled core impact: i) cell mimics are expected to reduce the pressure to obtain donor cells, ii) the integrated biocatalytic subunits are destined to take over tasks of the damaged liver slowing down the progress of liver damage, and iii) the matching micro-environment in the bioprinted tissue is anticipated to facilitate the connection between the transplant and the liver. Success criteria of ArtHep include engineering enzyme-mimics, which can perform core biocatalytic conversions similar to the liver, the assembly of biocatalytic active subunits and their encapsulation in cell-like carriers (microreactors), which have mechanical properties that match the liver tissue and that have a camouflaging coating to mimic the surface cues of liver tissue-relevant cells. Finally, matured bioprinted liver-lobules consisting of microreactors and live cells need to connect to liver tissue when transplanted into rats. I am convinced that the ground-breaking research in ArtHep will contribute to the excellence of science in Europe while providing the game-changing foundation to counteract the ever increasing donor liver shortage. Further, consolidating my scientific efforts and moving them forward into unexplored dimensions in biomimicry for medical purposes, is a unique opportunity to advance my career.

1 992 289 €

Start date: 2019-05-01, End date: 2024-04-30

I propose to study how eukaryotic cells generate autophagosomes, organelles bounded by a double membrane. These are formed during autophagy and mediate the degradation of cytoplasmic substances within the lysosomal compartment. Autophagy thereby protects the organism from pathological conditions such as neurodegeneration, cancer and infections. Many core factors required for autophagosome formation have been identified but the order in which they act and their mode of action is still unclear. We will use a combination of biochemical and cell biological approaches to elucidate the choreography and mechanism of these core factors. In particular, we will focus on selective autophagy and determine how the autophagic machinery generates an autophagosome that selectively contains the cargo. To this end we will focus on the cytoplasm-to-vacuole-targeting pathway in S. cerevisiae that mediates the constitutive delivery of the prApe1 enzyme into the vacuole. We will use cargo mimetics or prApe1 complexes in combination with purified autophagy proteins and vesicles to reconstitute the process and so determine which factors are both necessary and sufficient for autophagosome formation, as well as elucidating their mechanism of action. In parallel we will study selective autophagosome formation in human cells. This will reveal common principles and special adaptations. In particular, we will use cell lysates from genome-edited cells in combination with purified autophagy proteins to reconstitute selective autophagosome formation around ubiquitin-positive cargo material. The insights and hypotheses obtained from these reconstituted systems will be validated using cell biological approaches. Taken together, our experiments will allow us to delineate the major steps of autophagosome formation during selective autophagy. Our results will yield detailed insights into how cells form and shape organelles in a de novo manner, which is major question in cell- and developmental biology.

1 999 640 €

Start date: 2016-03-01, End date: 2021-02-28