Weight loss (WL) interventions postpone age-related diseases and improve health span in a wide variety of species including humans, monkeys, rodents, flies and yeast. These interventions such as dietary/caloric restriction (DR/CR) or bariatric surgery in formerly obese humans lead to a reprogramming of adipose tissue physiology with a better adipokine profile, insulin sensitivity and beneficial effects on adipose stem cells (ASCs) as protection against DNA damage, improvement of survival capacity, extension of replicative lifespan and holding adipogenesis at a low rate (Mitterberger et al,. 2014, Exp. Gerontol.). The research project is WL target genes in ASCs from subcutaneous White Adipose Tissue.

To find WL target genes, a microarray analysis was performed by the lab to establish the global gene expression pattern in ASCs of calorically restricted formerly obese (WLD), normal weight (NWD) and obese donors (OD). From this screening, it appears that the gene Sushi Domain Containing 2 (SUSD2) is upregulated after WL in ASCs of WLD compared to NWD and OD. As a consequence, the goal of the project is to study the function of SUSD2 in ASCs. The hypothesis is that the downregulation of SUSD2 in ASCs induce hyper-activation of mitogenic pathway which leads to premature senescence of ASCs. To address this hypothesis, genomic, transcriptomic and proteomic technologies, modern techniques of molecular and cell biology will be employed.

Seeds are the basis of agriculture and conservation. A €30 billion industry relies on storage of seed prior to their use for human and animal nutrition as well as later use for reproducing new plants. Although “orthodox” (desiccation tolerant) seeds can be stored long-term, they deteriorate over time. The mechanisms of seed ageing are not fully understood, but evidence is emerging that the processes that lead to seed death depend on oxygen concentration and molecular mobility. My PhD project is intended to elucidate the underlying mechanisms of seed and plant ageing. We hypothesize that “dry” seeds die due to random damage of macromolecules by oxidative damage, whereas programmed cell death (PCD) contributes to seed death as the cytoplasm becomes more fluid upon water uptake. The overall aim is to investigate the molecular mechanisms of ageing over the entire lifecycle of Arabidopsis, from seed germination to seedling establishment to leaf senescence.

As an ESR of the MSCA program ARDRE, her current research is focused on the study of skin aging and the role of dysfunctional mitochondrial metabolism and mitophagy in the triggering of senescence, a 3D culture model subjected to different stressors (UV, air pollutants) will be established. Her work is also focused on the investigation of FAHD1, a newly identified human mitochondrial enzyme, studying its role in various metabolic shifts, and its possible consequences on the functioning of the electronic transport chain and cell proliferation.

Lucas enrolled in the ARDRE program under the supervision of Prof. Thedieck to combine theoretical and experimental approaches in exploring the interplay of mTOR signaling with energy metabolism and neuronal function in the context of ageing.

The team is working on the hydrozoan freshwater polyp Hydra, which is part of Cnidarians as a sister-group of Bilateria. Hydra is a powerful model in biology for axial patterning, regeneration studies and stem cell biology, and allows us to understand ancestral mechanisms diverged from early metazoans. This polyp reproduces asexually and has a 

strong regeneration ability thanks to a hydrozoan-specific multipotent stem cell population, called the interstitial stem cells. Dynamic of this stem cell population is very constant in terms of cell proliferation, movement and proportions of cell type during asexual reproduction. Stem cell decision-making in this simple model raise an interest in the scientific community to understand the underlying genetic regulation system. Two core regulators of stem cells are the Wnt/ β-Catenin signalling pathway and the Myc oncogene, which are both highly conserved through evolution. The PhD project will aim to decipher these regulation mechanisms at cellular and molecular level in Hydra. In a first part, we want to establish Myc mutants by genetic interference, with Knock-down (siRNA) and Knock-out (CRISPR/Cas9) methods, or establish long-term and stable transgenic lines, in order to interfere with Myc. In a second part, we will use these successful Myc-inhibited Hydra and take advantage of transgenic β-Catenin over-expressing Hydra to decipher stem-cell regulation. The cell cycle and dynamics of interstitial stem cells will be analysed. Then, we will analyse at the molecular level by using transcriptomic analysis at single cell resolution. Finally, we want to extend this work depending on the result to decipher the molecular network and stem cells dynamics which control the decision making. We expect to collaborate with other ARDRE PhD candidates about related topics like repressive mechanisms of TCF/ β-Catenin or mitochondria dysfunction in ageing Hydra.

The activation of Wnt signalling is of central role in the pluripotency context. The Wnt pathway is present in almost all animals from sponges to human. It is well conserved evolutionary and plays important roles in the activation of target genes in a variety of cellular processes, such as cell proliferation, axis formation, embryonic patterning, organ development and stem cell renewal. Novel repressive functions of its nuclear effectors influencing gene expression and cell fate choice were discovered by the host lab in Ciona intestinalis, where Tcf and its cofactor β-catenin can directly repress the gata.a binding activity at GATA sites. More recently, a mechanistic model was suggested where Tcf7/β-catenin repress the gata.a transcriptional activity by preventing gata.a from binding to its site through the formation of a ternary complex, but several questions remain open to discussion. We hypothesize that Tcf alone can bind GATA sites independently of βcatenin and that a GATA site signature likely determines diverse degrees of repression translating into a fine tuning for tissue specific expression levels at the various GATA target genes in different regions of the embryo. Such signature may be determined by overlapping incomplete Tcf sites resulting in the masking of the GATA sites by Tcf to weaken the gata.a binding strength. The aims of this project are to refine the repressive signature of Tcf/βcatenin on different GATA sites by correlating the GATA signature with known activities of target genes. To test the repressive mechanism in other contexts in Ciona and to define a possible conservation in stemness in other species, we will isolate and analyse cis-regulatory regions of ß-catenin/Tcf repressed target genes in the Ciona context and probe for a conserved biochemical interaction between the Wnt nuclear effectors and to target DNA.

Pancreatic acinar cells make up for the largest number of cells in the pancreas. There are various studies showing the outstanding growth capacity and interesting cell fate plasticity of acinar cells. A previous research using zebrafish models for acinar cells ablation could discover a new population of cells in the exocrine pancreas expressing ptf1a as an early pancreatic development marker yet negative for acinar cell maturation markers. These progenitor-like cells seemed to be involved in acinar cell regeneration after near complete ablation. Our goal in this project is to further describe the identity and function of this cell population using single-cell, molecular and in-vivo imaging approaches and to look for the other possible early progenitors involved in exocrine pancreas regeneration.

In this project, we will study the regeneration processes of the adult human brain by deploying a novel approach of direct conversion of human fibroblasts into induced NSCs (iNSCs), which allows the (partial) maintenance of the ageing profile of the cells. The reprogramming trajectories will be studied over time at single cell level, assessing the transcriptomic and epigenetic profile of the cells. This experimental design will lead to valuable knowledge into stem cell reprogramming in the human brain and allow the establishment of a rejuvenation/ reprogramming cell atlas. A second aim of the project will be to decipher the molecular mechanisms that are involved in age-dependent changes in regeneration and the potential pathological mechanisms leading to neurodegenerative disorders. For that, the ageing profiles of iNSCs will be compared to profiles of induced pluripotent stem cells (iPSCs), iPSC- derived NSCs and their parental fibroblasts. For this purpose, single-cell age-related DNA methylation signatures will be analyzed and compared between the groups. In order to answer these complex scientific questions, state-of-the-art technologies are going to be employed. The innovative method of direct conversion of adult differentiated cells into iNSCs and induced Neurons (iNs) will be used and subsequently a serial combinatorial cell-indexing approach (CellTagging) will be performed, followed by single cell transcriptomics (high-throughput droplet microfluidics, scRNA-seq), high resolution lineage analysis, DNA methylation ageing analysis as well as neuronal functionality assays.

Coming soon!

During the study, we try to link the functional changes of calcium channels with their amino acid sequences via simulations of these channels at molecular level.
 

Coming soon!

Lichens are a symbiosis of a fungus (usually an Ascomycete), termed “mycobiont”, and one or more green microalgae and/or cyanobacteria, called “photobiont”. Secondary lichen products have been broadly employed in folk medicine, and screening campaigns revealed the occurrence of lichen metabolites with antibiotic, antimycotic, antibacterial, antiviral, antitumor, analgesic, antipyretic, antidiabetic, anticoagulant, antithrombotic, antioxidant, cardio-protective and anti-inflammatory properties. Regardless of the well-known bioactive properties of lichen compounds, most lichens are not commonly consumed by humans, due to the risk of intoxication. There are nevertheless some lichen species across the world, which are used as a food source, e.g. Cetraria islandica, Umbilicaria esculenta or Bryoria fremontii. One of the main drawbacks lichens present as a source for new bioactive products is their biomass production. Due to their slow growth rate and difficulties in cultivation, the production of substantial amounts of the compounds of interest is still challenging. It is noteworthy that the secondary metabolite profile of batches produced in culture might differ from those produced in nature, because lichenized fungi produce their typical “lichen products” almost exclusively in the presence of their compatible photobionts and under specific stressing environmental conditions. Biotechnological applications to produce new pharmaceuticals would require the development of novel culture techniques for edible lichens, by which the production of the desired secondary metabolites can be induced. Alternatively, compounds of interest might be synthesized. During this thesis, it is planned to compare secondary metabolite profiles of lichen extracts from species collected in nature and grown in culture. In a first attempt C. islandica, which is used traditionally as herbal cough remedy, but also for the treatment of dysentery and chronic digestive disturbances, will be investigated. Secondary metabolites of interest will be isolated, their structures assigned, and their pharmacological profile studied. Particular attention will be given to their effects on inflammation inhibition, humane tyrosinase inhibition, enhancement of wound healing (e.g. MMP-9 inhibition), and their activity on tumor cells. In a second task, the metabolic faith of secondary lichen metabolites after oral intake will be investigated, taking advantage of in vitro assays that simulate digestion. Besides C. islandica, further edible lichens growing in different areas of Europe, including the Austrian Alps, will be studied.