Selectivity modeling of fungicides inhibiting cytochrome P450 enzymes   

Several Cytochrome P450 (CYP) enzymes play a role in steroid hormone synthesis, e.g. aromatase or aldosterone synthase. They can be potently inhibited by fungicides containing azole moieties, thereby potentially interfering with hormone homeostasis. However, the selectivity of CYP inhibition and the respective binding modes of the inhibitors are still poorly understood. This master thesis aims to rationalize the selectivity of CYP inhibition using computational approaches such as pharmacophore modeling and docking studies. The results could help to understand and possibly avoid unintentional CYP inhibition by future fungicides.

Contact: daniela.schuster@clutterpmu.ac.at  Tel: 0699/14420025

Univ.-Prof. Daniela Schuster

Paracelsus Medizinische Privatuniversität

Leiterin Abteilung Pharmazeutische und Medizinische Chemie

Strubergasse 21, 5020 Salzburg, Österreich 

Dihydrochalcones as multi-target anti-inflammatory and anti-cancer targets: SAR modeling on selected targets    

Dihydrochalcones are natural products with multiple biological activities. For example, they have been shown to act on anti-inflammatory and anti-prostate-cancer targets. This multi-target activity could be an attractive strategy to combat multi-factorial diseases such as cancer in the future. In this project, computational approaches such as docking and pharmacophore-based screening will be used to rationalize the activity data of a series of dihydrochalcones against several targets and to propose improved compounds for future synthesis.

Contact: daniela.schuster@clutterpmu.ac.at Tel: 0699/14420025

Univ.-Prof. Daniela Schuster

Paracelsus Medizinische Privatuniversität

Leiterin Abteilung Pharmazeutische und Medizinische Chemie Strubergasse 21, 5020  Salzburg, Österreich 

Investigation of effects of combination therapy in cancer treatment  

The research focus of the Department of Pharmaceutical Biology and Clinical Pharmacy at the PMU Salzburg lies on the study of mechanisms involved in cancer pathogenesis, progression and therapy resistance. The aim of our group is to optimize cancer treatment strategies through combination therapy of biogenic or synthetic drugs. Currently, the effects of combination therapy on a wide range of tumor cells derived from liver and thyroid carcinomas are evaluated with state of the art methods including proliferation, migration and clonogenic survival assays as well as diverse biochemical techniques and confocal microscopy.

Contact: Johanna.pachmayr@clutterpmu.ac.at

Paracelsus Medizinische Privatuniversität

Strubergasse 21, 5020  Salzburg, Österreich 

Investigate the influence of bariatric surgery on corticosteroid homeostasis

Glucocorticoids play an essential role in regulating energy metabolism and storage, but also regulate immune responses, whereas mineralocorticoids have an essential role in electrolyte and blood pressure control.

There is evidence for dysregulation of corticosteroid homeostasis in Diet Induced Obesity (DIO) mice and obese humans. Glucocorticoid reactivation has been found to be decreased in liver tissue but increased in adipose tissue, associated with adverse metabolic effects. In addition, the glucocorticoid feedback by the Hypothalamic-Pituitary-Axis was found to be impaired in obese patients. In addition, elevated concentrations of the mineralocorticoid aldosterone were measured in obese patients. After gastric surgery, an improvement of the dysregulated corticosteroid homeostasis was observed. However, up to now, no comprehensive study is available.

Aim: In the proposed project, we will address how gastric surgery can partially reverse the dysregulated corticosteroid homeostasis. We will analyze samples from a mouse study, obtained from our collaborators, to explore the mechanisms underlying changes following gastric surgery. We aim to obtain a more systemic view of the improvement of corticosteroid homeostasis after gastric surgery.

Methods: RNA/protein extractions and quantification, Western blotting and qPCR. Data analysis.

This work will be conducted in the laboratory of Molecular and Systems Toxicology, University of Basel

Anti-androgenic effects of xenobiotics inhibiting 17β-HSD6

Androgen production is important for male sexual development and physiology. 5α-Dihydrotestosterone (DHT) is the most potent human androgen and is usually produced by the classic pathway, involving 5α-reduction of testosterone to DHT. An alternative pathway of DHT synthesis, originally discovered in marsupials, is important for early male development. In this so-called backdoor pathway, androsterone acts as an intermediate and is either converted to androstanedione by 17β-hydroxysteroid dehydrogenase type 6 (17β-HSD6) and then reduced to DHT by a 17β‑reductase, or reduced first to 3α-androstanediol by a 17β-reductase and then 3α-oxidized by 17β‑HSD6 to DHT. Molecular analysis has identified pathologic mutations in genes involved in the backdoor pathway in human genetically male patients, resulting in a phenotype with undermasculinized external genitalia. Therefore, 17β-HSD6, which is involved in the same pathway, should also play a crucial role in early male development. Additionally, androgen receptor (AR) activity plays an important role in androgen-dependent prostate cancer, in which often the classic pathway is chemically blocked by therapeutic drugs. Those hormone ablation treatments are not 100% effective and additionally blocking 17β-HSD6 may improve treatment efficacy. Besides 17β-HSD6, other 3α-hydroxysteroid dehydrogenases (3α-HSDs) such as retinol dehydrogenase 5 (RDH5) and retinol dehydrogenase 16 (RDH16) catalyze the same 3α-reduction of androstanediol and androsterone. The potential roles of these 3α‑HSDs in human have not been characterized well. In vitro identification of enzyme-specific inhibitors for 17β-HSD6, RDH5 and RDH16 may be useful for further in vivo studies to identify additional roles of 3α-HSDs.

Aims: We first aim to identify xenobiotics or commercially used drugs, that may exert an anti-androgenic effect during male development through inhibition of 17β-HSD6 or which could be used as additional prostate cancer treatment in adults by blocking DHT synthesis through 17β-HSD6 inhibition. Experimentation will include an in vitro enzymatic assay for 17β-HSD6. In a next step, novel assays to assess RDH5 and RDH16 activity will be established by adapting an already established enzyme activity assay of 17β-HSD6. Subsequently, the inhibitory capacity of identified 3α-HSD inhibitors will be assessed on 17β-HSD6, RDH5 and RDH16. The results will be validated using an androgen receptor transactivation assay in intact cells.

RESIGEST – Does the superbug from my salad make it to my intestine?

Introduction
The demand for a healthy, varied diet goes along with an increased consumption of fresh produce like vegetables, salads, and fruits. These foods are often consumed uncooked or minimally processed, making them an optimal vector of live bacteria for consumers. Apart from occasionally carrying human pathogenic bacteria, fresh produce has been described to harbor antibiotic-resistant bacteria (ARB). The latter usually do not represent a direct health risk in terms of infection. However, if they survive the gastric passage through to the intestine, they might establish and exchange mobile antibiotic resistance genes (ARGs) with the gut microbiome, complicating later antibiotic treatments.
Project Aim
Currently, very little is known about the extent to which ARB survive the passage through the human gastrointestinal tract (GIT), especially in dependence of the different foods with which they are ingested. The proposed project therefore aims to determine the survival of a set of ARB with clinically relevant resistances in association with different fresh produce, using the in vitro digestive model system INFOGEST [1, 2]. In addition to survival in dependence on the food matrix, the effect of the GIT passage on the maintenance of resistance will also be investigated (e.g., loss of resistance plasmid during the passage).
Material and Methods
A collection of non-pathogenic ARB isolated from fresh produce and its production environment, such as extended-spectrum β-lactamase–producing Escherichia coli (non-pathogenic BSL1 organism) [3], will be tested with different fresh produce (lettuce, carrot, and strawberries). The methods will include standard microbiological culture techniques, handling of the INFOGEST in vitro system, flow-cytometry (FACS) for bacterial enumeration and live-dead quantification, and an established real-time PCR (qPCR) for quantification of ARGs before, during, and after ARB passage through the in vitro system.

1.    Brodkorb, A., et al., INFOGEST static in vitro simulation of gastrointestinal food digestion. Nature Protocols, 2019.
2.    Mulet-Cabero, A.I., et al., A standardised semi-dynamic in vitro digestion method suitable for food - an international consensus. Food Funct, 2020.
3.    Gekenidis, M.T., et al., Antibiotic-resistant indicator bacteria in irrigation water: High prevalence of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli. PLoS One, 2018.

Contact: reto.portmann@clutteragroscope.admin.ch / Phone: 079 647 9322

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Workplace:

Agroscope, Schwarzenburgstrasse 161, 3097 Liebefeld 

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Investigating xenobiotics-induced disturbances of hepatic sterol and bile acid metabolism