2017 - FFoQSI
K1-competence center for Feed Food Quality Safety and Innovation
(FFG, Federal States of Upper Austria, Lower Austria and Vienna, 16.4 Mio. Euro)
2016 - LipoDrop
Identification of phytogenic substances for reduced intracellular lipid storage in lipid droplets (University of Applied Sciences Upper Austria Basic Funding; 70 000.-)
2015 – PhytoSTAR
Identification and characterization of herbal compounds with antidiabetic properties (FFG Bridge 1 380 000.-)
2015 – GlucoSTAR
High-content screening platform for identification and characterization of insulin-mimetic substances (University of Applied Sciences Upper Austria Basic Funding, 80 000.-)
2014 – StarPatt
Development of a high-through-put (HTP) and high-content (HC) µ-patterning screening technique (FFG Bridge Frühphase, 320 000.-)
2013 – PhytoDoc
Obtaining a better understanding about the molecular mode of action of secondary plant metabolites (phytamines) in the human body. Establishment and employment of screening systems to identify effective phytamines (EFRE funding, 310 000.-)
2012 – Celmophyt
Investigation of bioavailability studies of phytamines with in-vitro cell culture models (FFG Basic funding, 40 000.-)
2011 - Detector | MicroProt
Development and improvement of a µ-patterning assay to detect the impact of phytamines on the signaling behaviour of important cell surface proteins in combination with bioinformatic-based data processing (University of Applied Sciences Upper Austria Basic Funding, 170 000.-)
2010 - Regio13: Functional Food
Basic research on functional food and bioenergy production (EFRE funding, 1 000 000.-)
Current work and developments
Determination of the impact of secondary plant metabolites on interactions of signal transduction molecules via µ-patterned surfaces
The adrenergic receptors, insulin receptor and EGF-receptor are important major drug targets for some of the most commonly prescribed drugs in the history of medicine. We have established a huge variety of cell lines which are stably expressing these receptors and some of their corresponding downstreaming molecules (e.g. Grb2, beta-arrestin, IRS1-3, GLUT4, G-proteins,...). We are interested in the detection of such protein-protein interactions by use of the µ-patterning assay. By means of this method we are able to screen biochemical properties of phytamins and drugs of interest.
Studying protein-protein interactions of beta-adrenergic receptors
β-adrenergic (βAR) receptors belong to the class of G protein-coupled receptors (GPCRs) and generally administrate the physiological response of adrenaline and noradrenaline. They can be classified into three receptor subtypes (β1, β2, β3) which are major drug targets for some of the most commonly prescribed drugs in the history of medicine. The various βAR subtypes also interact differentially with a huge diversity of cytoplasmic (G proteins, kinases,…) and transmembrane proteins (e.g. receptor homo-/hetero-multimerization, ion channels,…) leading to distinctive receptor signaling pathways. Studying such interaction processes of plasma-membrane localized receptor proteins is key for a better understanding of cellular processes. In the past few years, many studies indicated that βAR dimerization can occur between two identical receptors (homodimerization), between two different receptor subtypes of the same family or between receptors of different families (heterodimerization) (Bouvier, 2001; Milligan, 2004; Hall, 2004). The physiological role of such di-/multimerizations often remains a matter of debate and in most instances co-IP was used as the primary tool for verifying the existence of such dimers or multimers. We are interested in homo-/heteromultimerization processes of βARs and in their signaling with intracellular binding proteins such as G-proteins, arrestins and adenylate cyclases. We use an assay combining TIR (total internal reflection) microscopy and micro-patterned surfaces, which makes it possible to detect protein-protein interactions in and near the cell membrane in vivo.
Interaction properties of receptor tyrosine kinases
Receptor tyrosine kinases (RTK)s are high-affinity cell surface receptors for different growth factors, cytokines and hormones. They have been shown not only to be key regulators of normal cellular processes but also to have a critical role in the development and progression of many types of cancer. So far, approximately 20 different RTK classes have been identified. Among them the RTK class I (EGF receptor family) and class II (Insulin receptor family). We are mainly interested in the interaction properties of the EGF- and insulin-receptors with corresponding intracellular downstream signaling proteins such as Grb2 and IRS1-3, respectively.
Development of a novel GLUT4 translocation assay to study insulin-like phytamines
Insulin-stimulated translocation of GLUT4 (glucose transporter 4) to the cell membrane leading to glucose uptake is one of the rate-limiting steps in diabetes and it is also a defined target of antidiabetic drug research. Existing GLUT4 translocation assays are often very time consuming and show low sensitivity. We want to establish a real-time, live-cell GLUT4 translocation assay in combination with TIR microscopy and µ-patterned surfaces.
Bioavailability and impact on protein expression of secondary plant metabolites and extracts
In-vitro uptake experiments are well established tools for a rough estimation of the bioavailability for a substance of interest. We use a CaCo-2 (colon carinoma cells) and IPEC (porcine intestine cells) transwell system for studying the bioavailability of secondary plant metabolites. In addition we focused on protein expression analysis in HepaRG cells (liver cells) with RT-PCR for studying the effects of phytamines on phase I and II enzymes.
Development of an easy test system to examine the prevention of urease activity by saponins
A huge amount of ammonia emission in the nature is caused by agricultural ammonia volatilisation due to bacterial activity. The main pathway for bacterial ammonia production is hydrolytic deamination of urea into ammonia and carbon dioxide, catalyzed by the enzyme urease. Dietary applications of quillaja and yucca in livestock is reported to reduce ammonia formation from litter and slurry by inhibiting urease activity and binding of ammonia by plant substances. We developed an in vitro testing system for screening of plant substances for their potential to inhibit the activity of bacterial urease and to evaluate plant extracts by such a method.