Projects & Collaborations 27 foundShow per page10 10 20 50 ToxOligo2 - Toxicological properties of oligomers present in food contact materials Research Project | 6 Project MembersToxOligo addresses an important knowledge gap by evaluating toxicological properties of oligomers released from polymers as food contact materials (FCM). The formation and presence of oligomers is inevitable in such FCM. Despite known migration into food, these substances are toxicologically poorly characterized, preventing adequate risk assessment. The ongoing project phase allowed essential new insights into available information on oligomers from all polymeric FCM. A pilot study on PET helped to design an optimized strategy and workflow to address this task. Information on physicochemical, ADME and toxicological properties was collected using computational methods. In a second project phase, a collection of oligomers from all other materials will be made based on the obtained information. The focus will be on bioactivity assessment of these substances. Hazard profiles will be established using various in vitro assays to assess general toxicity, cellular stress pathways, macrophage activation and endocrine effects. These studies aim at assessing the level of concern of such substances and providing recommendations for prioritization of future toxicological testing. Evaluating endocrine disrupting chemicals and mixtures for ovarian cell toxicity and assessing a potential susceptibility factor Research Project | 2 Project MembersWe are assessing individual effects of bisphenol-A (BPA), phthalates and the respective replacement substances on ovarian cell toxicity. The project focuses on three parts: 1) assess disturbances of endoplasmic reticulum (ER) functions and evaluate a role for ER-stress by BPA, phthalates and the respective replacement substances, 2) investigate, if time allows, mixture effects on ovarian toxicity by focusing on ER functions, cellular stress and steroidogenesis, and 3) evaluate hexose-6-phosphate dehydrogenase (H6PD) as susceptibility factor of ovarian toxicity. Investigation of toxicological properties of oligomers present in food contact materials Research Project | 1 Project MembersThe project proposed for Dr. Serhii Kolesnyk is integrated in an ongoing project supported by the government (FOPH) and the Swiss Centre for Applied Human Toxicology to address an important knowledge gap by characterizing toxicological properties of oligomers released from food contact materials (FCM) such as plastics, adhesives, printing inks and coatings. Despite known high levels in FCM, these substances are toxicologically poorly investigated, preventing adequate risk assessment. In the project, in silico methods will be applied to predict physico-chemical and ADME properties, reactivity of building blocks, stability of oligomers, as well as endocrine disrupting potentials. Hazard profiles will be established for relevant selected oligomers using in vitro assays on general cytotoxicity, cellular stress pathways, macrophage activation, and endocrine regulation. Levels of concern will be estimated, information gaps identified, and recommendations for follow-on toxicological analyses and an evaluation concept for safety assessment of oligomers will be proposed.In the project, Dr. Kolesnyk will closely work with a postdoc, Dr. Verena Schreier. Prof. Martin Wilks (Swiss Centre for Applied Human Toxicology), PD Martin Smiesko (Computational Toxicology, University of Basel), and Prof. Alex Odermatt (Molecular and Systems Toxicology, University of Basel) will be responsible for guiding work in the field of regulatory toxicology, computational toxicology and biochemical toxicology, respectively. ToxOligo - Toxicological properties of oligomers present in food contact materials Research Project | 6 Project MembersToxOligo addresses an important knowledge gap by characterizing toxicological properties of oligomers released from food contact materials (FCM) such as plastics, adhesives, printing inks and coatings. Despite known high levels in FCM, these substances are toxicologically poorly investigated, preventing adequate risk assessment. A systematic review of the literature and expert interviews will provide insight on available knowledge of types of structures involved, exposure estimates and toxicological information. Physico-chemical and ADME properties, reactivity of building blocks, stability of oligomers, genotoxicity, endocrine disrupting potentials, and chronic and developmental toxicity will be predicted by in silico methods. Hazard profiles will be established for relevant selected oligomers using in vitro assays on general cytotoxicity, cellular stress pathways, neuronal cell toxicity, macrophage activation, and endocrine regulation. Selected FCM extracts will be considered to identify potentially hazardous materials. Levels of concern will be estimated, information gaps identified, and recommendations for follow-on toxicological analyses and an evaluation concept for safety assessment of oligomers will be proposed. Xenobiotics disrupting the corticosteroid - androgen balance Research Project | 3 Project MembersCorticosteroids have key roles in regulating essential physiological processes. Impairment of corticosteroid homeostasis has been associated with metabolic and cardiovascular disease, cancer, immune disorders and behavioural diseases. Importantly, corticosteroid and androgen signalling pathways influence each other and a tight regulation is essential to maintain body homeostasis. For example, glucocorticoids exert catabolic effects, and they inhibit proliferation and promote differentiation in many cell types, controlling essential developmental processes. In contrast, androgens act anabolic and promote the proliferation of several cell types, including cancer cells. Further, glucocorticoids inhibit testicular testosterone synthesis and sperm production, whilst androgens stimulate it. Moreover, glucocorticoids promote visceral obesity and fatty liver disease, whereas androgens exert protective effects (although regarding fatty liver disease sex-specific differences need to be taken into account). Increasing evidence indicates that, besides genetic predisposition, the exposure to xenobiotics can contribute to the development and progression of major diseases. However, despite the key role of corticosteroids and the corticosteroid - androgen balance, the impact of xenobiotics disrupting their function represents a neglected topic and research on endocrine disrupting chemicals (EDC) focused largely on estrogen receptors and reproductive toxicity (1, 2). In the proposed project, we investigate xenobiotics (environmental pollutants, industrial and occupationally relevant chemicals, body care products, food additives, supplements, recreational drugs, pharmaceuticals) that might disrupt the corticosteroid - androgen balance and how they do that. In WP1 we investigate xenobiotics-induced disturbances of corticosteroid - androgen balance in human and animals by assessing steroid concentrations and by attempting to define steroid metabolites and ratios thereof that serve as indicators of disturbances . Such markers of disturbed corticosteroid - androgen balance will facilitate the investigation of potential EDCs disturbing this balance. It should ultimately allow testing for correlation between a given compound, a steroid marker and a physiologic, respectively a disease read-out. In WP2 , we aim at investigating mechanisms of action of EDCs disturbing corticosteroid - androgen balance in cell-based models , focusing on glucocorticoid- and androgen receptor resistance and on mechanisms of altered expression of glucocorticoid and androgen metabolizing enzymes . Finally, in WP3 we aim to extend our previously established expertise and tools to identify hazardous chemicals and to study chemical-protein interactions (3-9), providing novel information for molecular initiating events (MIE). These studies mainly focus on two topics: 1) xenobiotics interfering with corticosteroid synthesis/metabolism and causing mineralocorticoid-dependent hypertension and cardiovascular disease ; and 2) xenobiotics disturbing glucocorticoid - androgen balance in hepatocytes and adipocytes and contributing to non-alcoholic fatty liver disease (NAFLD) and visceral obesity. Xenobiotics identified in the in silico/in vitro testing will be further investigated using cell-based models in WP2 and if appropriate, in animals and in human in WP1. Development of in silico screening tools and in vitro bioassays for 5α- and 5β-reductase Research Project | 3 Project MembersThe proposed project focuses on two important enzymes involved in the hepatic metabolism/degradation of steroid hormones in the human body: 5α-reductase (SRD5A1) and 5β-reductase (AKR1D1). More exactly, both enzymes are very important in maintaining the androgen-glucocorticoid balance. Thus, any undesired interaction (inhibition) by small molecules (e.g. drugs, cosmetics, food additives, natural compounds) would result in altered activity of the enzymes and potentially lead to disruption of the steroid homeostasis. Increased levels of glucocorticoids may severely affect human health in terms of increased risk for development of metabolic diseases, including diabetes and non-alcoholic fatty liver disease (NAFLD) or non-alcoholic steatohepatosis (NASH) [1-3]. The main goal of this project proposal is to develop in silico predictive models for screening of small molecules in order to rapidly and reliably identify their undesired interaction with the two enzymes. The project requests one year funding for a PhD student who will get training and subsequently apply various state-of-the-art modeling techniques like molecular docking, pose scoring, homology modeling, molecular dynamics simulations to elucidate enzyme-ligand interactions at the atomic level in silico as well as establish experimental activity assays for initial testing and validation of screening hits. The modelling information together with the enzyme activity data will allow defining structure-activity-relationships for the two enzymes. 1. Nasiri M, Nikolaou N, Parajes S, Krone NP, Valsamakis G, Mastorakos G, Hughes B, Taylor A, Bujalska IJ, Gathercole LL, Tomlinson JW: 5α-Reductase Type 2 Regulates Glucocorticoid Action and Metabolic Phenotype in Human Hepatocytes. Endocrinology. 2015, 156(8):2863-71. doi: 10.1210/en.2015-1149. 2. Dowman JK, Hopkins LJ, Reynolds GM, Armstrong MJ, Nasiri M, Nikolaou N, van Houten EL, Visser JA, Morgan SA, Lavery GG, Oprescu A, Hübscher SG, Newsome PN, Tomlinson JW.: Loss of 5α-reductase type 1 accelerates the development of hepatic steatosis but protects against hepatocellular carcinoma in male mice. Endocrinology. 2013, 154(12):4536-47. doi: 10.1210/en.2013-1592. 3. Upreti R, Hughes KA, Livingstone DE, Gray CD, Minns FC, Macfarlane DP, Marshall I, Stewart LH, Walker BR, Andrew R.: 5α-reductase type 1 modulates insulin sensitivity in men. J. Clin. Endocrinol. Metab. 2014, 99(8):E1397-406. doi: 10.1210/jc.2014-1395. "In vitro" Testung des Potentials endokriner Aktivität von Druckfarbstoffen Research Project | 2 Project MembersA total of 20 food ink chemicals will be tested for potential interferences with the activities of several steroid hormone receptors, including estrogen-, androgen-, progesterone-, mineralocorticoid-, and glucocorticoid receptor. Both agonist and antagonist mode will be assessed. The compounds were selected based on in silico predictions using the Virtual Tox-Lab. Impact of the NADPH Pool in the Endoplasmic Reticulum on Metabolic and Hormonal Regulation Research Project | 1 Project MembersAn impaired redox control in the endoplasmic reticulum (ER) with unfolded-protein response (UPR) and ER-stress has been associated with major diseases such as cancer, cardio-metabolic disorders, and chronic inflammatory diseases. Thus, it is crucial to elucidate the mechanisms underlying ER-redox control and identify involved modulators and biological reactions. The NAD(P)H/NAD(P) + redox couple is essential for many biological functions and, in contrast to the cytoplasm, its regulation in the ER and the relevance of luminal NADPH for physiological functions such as intracellular calcium signaling, UPR control, and the metabolism of glucose, fatty acids, oxysterols, and glucocorticoids is insufficiently understood. The discovery of hexose-6-phosphate dehydrogenase (H6PDH) revealed a mechanism for luminal NADPH generation and provided a link between energy status and glucocorticoid signaling. To date, 11b-hydroxysteroid dehydrogenase 1 (11b-HSD1) is still the only well characterized NADPH-dependent luminal enzyme. Besides its well-known role in glucocorticoid activation and involvement in metabolic and inflammatory diseases, increasing evidence revealed a role of 11b-HSD1 in oxysterol and bile acid metabolism, warranting further studies. Moreover, there must be other NADPH-dependent enzymes because 11b-HSD1 cannot account for the myopathy and increased susceptibility of hepatocytes toward toxicants observed in situations of H6PDH-deficiency. Based on previous results, we hypothesize that 1) the ratios of certain bile acids serve as potential prognostic markers for decreased 11b-HSD1 activity in rodents and human, 2) 11b-HSD1 is involved in the formation of dihydroxylated oxysterols that modulate the activities of nuclear receptors (ROR, ERβ, LXRβ) and the G-coupled receptor EBI2, 3) H6PDH delivers NADPH for fatty acid elongation in the ER, which is needed for rapid cell proliferation, 4) loss of H6PDH affects UPR and renders cells susceptible to substances causing ER-stress, and 5) other enzymes generating and utilizing NADPH in the ER exist and need to be identified and characterized. To study the consequences of ER NADPH depletion on hormonal and metabolic functions, and to identify and characterize novel modulators of luminal NADPH, we propose to: evaluate whether ratios of certain 7oxo to 7β-hydroxy bile acids in plasma/serum can serve as markers for reduced 11b-HSD1 activity in human, further explore the role of 11b-HSD1 in oxysterol and bile acid metabolism and the modulation of cognate receptors, study other enzymes generating or utilizing NADPH in the ER, study the impact of H6PDH on fatty acid synthesis/metabolism, investigate the impact of H6PDH on breast cancer cell properties, study the susceptibility of H6PDH-deficient primary liver and kidney cells to ER-stress, and explore the use of IP-MS and BioID to investigate protein-protein interactions in the ER. Steroids and other lipophilic compounds in different matrices will be quantified using LC-MS/MS. The role of luminal NADPH and consequences of its depletion on metabolic and hormonal responses will be studied using enzyme preparations, cell-based models upon modulating the corresponding enzyme(s) by overexpression, downregulation by siRNA or pharmacological inhibition. Further, studies in transgenic mice and mice treated with inhibitors and in primary cells will be performed. Also, protein interaction methods will be employed, attempting to identify novel players in ER NADPH regulation. The proposed research should significantly enhance our current knowledge on the role of NADPH in the ER. The expected findings are relevant to understand the coupling between cellular energy state, hormonal regulation, ER redox regulation, and oxidative stress-induced damage. Disturbed functions of the enzymes studied are associated with impaired inflammatory responses, cardio-metabolic disorders and cancer, and the results of the proposed project should support the future development of therapeutic interventions. Chemicals Disrupting Adrenal Steroidogenesis and/or Peripheral Steroid Action Research Project | 1 Project MembersRationale for the research area An increasing number of chemicals have been suspected of mimicking hormonal effects and altering steroid hormone regulation. Endocrine-disrupting chemicals (EDCs) may contribute to the development and progression of major diseases, including developmental disorders, immune diseases, various forms of cancer and cardio-metabolic diseases such as diabetes, but the mechanisms underlying chemical-induced disruption of endocrine functions are often unknown. Thus, there is a great demand to identify key events of disrupted steroid homeostasis, as well as to develop suitable tools - in vitro and in silico - for early detection of chemical-induced disturbances of steroid homeostasis. Objectives The aim is to generate experimental data that can serve as a basis to improve regulatory test systems for the characterisation of EDCs affecting steroidogenesis and peripheral steroid action. Current regulatory tests for EDCs focus on effects on oestrogen, androgen, and thyroid receptor signalling and on sex steroid production, but do not adequately assess mineralocorticoids, glucocorticoids and adrenal androgens. The proposed project aims to refine the use of the established regulatory cell-based test system (the human adrenal cancer cell line H295R) to characterise effects on these other steroids. Furthermore, effects of EDCs on peripheral steroid action will be investigated by employing computer-based models, biological testing systems and using targeted and untargeted steroid profiling and gene expression analyses. Regulatory Significance Regulatory authorities are participating in large-scale projects on chemical safety, focusing on substances that disrupt endocrine functions; however, the currently available methods and potential targets under investigation are still highly limited, and additional testing strategies are required. The tools to be developed in this project should help in the identification of potentially hazardous chemicals, and the steroidomic profiling should facilitate the investigation of their modes of action and thus risk assessment in humans. Transcriptomic investigations into drug hypersensitivity towards carboxyllic acid containing compounds Research Project | 2 Project MembersInvestigation of drug adducts in patients treated with carboxylic acid containing compounds 123 123
ToxOligo2 - Toxicological properties of oligomers present in food contact materials Research Project | 6 Project MembersToxOligo addresses an important knowledge gap by evaluating toxicological properties of oligomers released from polymers as food contact materials (FCM). The formation and presence of oligomers is inevitable in such FCM. Despite known migration into food, these substances are toxicologically poorly characterized, preventing adequate risk assessment. The ongoing project phase allowed essential new insights into available information on oligomers from all polymeric FCM. A pilot study on PET helped to design an optimized strategy and workflow to address this task. Information on physicochemical, ADME and toxicological properties was collected using computational methods. In a second project phase, a collection of oligomers from all other materials will be made based on the obtained information. The focus will be on bioactivity assessment of these substances. Hazard profiles will be established using various in vitro assays to assess general toxicity, cellular stress pathways, macrophage activation and endocrine effects. These studies aim at assessing the level of concern of such substances and providing recommendations for prioritization of future toxicological testing.
Evaluating endocrine disrupting chemicals and mixtures for ovarian cell toxicity and assessing a potential susceptibility factor Research Project | 2 Project MembersWe are assessing individual effects of bisphenol-A (BPA), phthalates and the respective replacement substances on ovarian cell toxicity. The project focuses on three parts: 1) assess disturbances of endoplasmic reticulum (ER) functions and evaluate a role for ER-stress by BPA, phthalates and the respective replacement substances, 2) investigate, if time allows, mixture effects on ovarian toxicity by focusing on ER functions, cellular stress and steroidogenesis, and 3) evaluate hexose-6-phosphate dehydrogenase (H6PD) as susceptibility factor of ovarian toxicity.
Investigation of toxicological properties of oligomers present in food contact materials Research Project | 1 Project MembersThe project proposed for Dr. Serhii Kolesnyk is integrated in an ongoing project supported by the government (FOPH) and the Swiss Centre for Applied Human Toxicology to address an important knowledge gap by characterizing toxicological properties of oligomers released from food contact materials (FCM) such as plastics, adhesives, printing inks and coatings. Despite known high levels in FCM, these substances are toxicologically poorly investigated, preventing adequate risk assessment. In the project, in silico methods will be applied to predict physico-chemical and ADME properties, reactivity of building blocks, stability of oligomers, as well as endocrine disrupting potentials. Hazard profiles will be established for relevant selected oligomers using in vitro assays on general cytotoxicity, cellular stress pathways, macrophage activation, and endocrine regulation. Levels of concern will be estimated, information gaps identified, and recommendations for follow-on toxicological analyses and an evaluation concept for safety assessment of oligomers will be proposed.In the project, Dr. Kolesnyk will closely work with a postdoc, Dr. Verena Schreier. Prof. Martin Wilks (Swiss Centre for Applied Human Toxicology), PD Martin Smiesko (Computational Toxicology, University of Basel), and Prof. Alex Odermatt (Molecular and Systems Toxicology, University of Basel) will be responsible for guiding work in the field of regulatory toxicology, computational toxicology and biochemical toxicology, respectively.
ToxOligo - Toxicological properties of oligomers present in food contact materials Research Project | 6 Project MembersToxOligo addresses an important knowledge gap by characterizing toxicological properties of oligomers released from food contact materials (FCM) such as plastics, adhesives, printing inks and coatings. Despite known high levels in FCM, these substances are toxicologically poorly investigated, preventing adequate risk assessment. A systematic review of the literature and expert interviews will provide insight on available knowledge of types of structures involved, exposure estimates and toxicological information. Physico-chemical and ADME properties, reactivity of building blocks, stability of oligomers, genotoxicity, endocrine disrupting potentials, and chronic and developmental toxicity will be predicted by in silico methods. Hazard profiles will be established for relevant selected oligomers using in vitro assays on general cytotoxicity, cellular stress pathways, neuronal cell toxicity, macrophage activation, and endocrine regulation. Selected FCM extracts will be considered to identify potentially hazardous materials. Levels of concern will be estimated, information gaps identified, and recommendations for follow-on toxicological analyses and an evaluation concept for safety assessment of oligomers will be proposed.
Xenobiotics disrupting the corticosteroid - androgen balance Research Project | 3 Project MembersCorticosteroids have key roles in regulating essential physiological processes. Impairment of corticosteroid homeostasis has been associated with metabolic and cardiovascular disease, cancer, immune disorders and behavioural diseases. Importantly, corticosteroid and androgen signalling pathways influence each other and a tight regulation is essential to maintain body homeostasis. For example, glucocorticoids exert catabolic effects, and they inhibit proliferation and promote differentiation in many cell types, controlling essential developmental processes. In contrast, androgens act anabolic and promote the proliferation of several cell types, including cancer cells. Further, glucocorticoids inhibit testicular testosterone synthesis and sperm production, whilst androgens stimulate it. Moreover, glucocorticoids promote visceral obesity and fatty liver disease, whereas androgens exert protective effects (although regarding fatty liver disease sex-specific differences need to be taken into account). Increasing evidence indicates that, besides genetic predisposition, the exposure to xenobiotics can contribute to the development and progression of major diseases. However, despite the key role of corticosteroids and the corticosteroid - androgen balance, the impact of xenobiotics disrupting their function represents a neglected topic and research on endocrine disrupting chemicals (EDC) focused largely on estrogen receptors and reproductive toxicity (1, 2). In the proposed project, we investigate xenobiotics (environmental pollutants, industrial and occupationally relevant chemicals, body care products, food additives, supplements, recreational drugs, pharmaceuticals) that might disrupt the corticosteroid - androgen balance and how they do that. In WP1 we investigate xenobiotics-induced disturbances of corticosteroid - androgen balance in human and animals by assessing steroid concentrations and by attempting to define steroid metabolites and ratios thereof that serve as indicators of disturbances . Such markers of disturbed corticosteroid - androgen balance will facilitate the investigation of potential EDCs disturbing this balance. It should ultimately allow testing for correlation between a given compound, a steroid marker and a physiologic, respectively a disease read-out. In WP2 , we aim at investigating mechanisms of action of EDCs disturbing corticosteroid - androgen balance in cell-based models , focusing on glucocorticoid- and androgen receptor resistance and on mechanisms of altered expression of glucocorticoid and androgen metabolizing enzymes . Finally, in WP3 we aim to extend our previously established expertise and tools to identify hazardous chemicals and to study chemical-protein interactions (3-9), providing novel information for molecular initiating events (MIE). These studies mainly focus on two topics: 1) xenobiotics interfering with corticosteroid synthesis/metabolism and causing mineralocorticoid-dependent hypertension and cardiovascular disease ; and 2) xenobiotics disturbing glucocorticoid - androgen balance in hepatocytes and adipocytes and contributing to non-alcoholic fatty liver disease (NAFLD) and visceral obesity. Xenobiotics identified in the in silico/in vitro testing will be further investigated using cell-based models in WP2 and if appropriate, in animals and in human in WP1.
Development of in silico screening tools and in vitro bioassays for 5α- and 5β-reductase Research Project | 3 Project MembersThe proposed project focuses on two important enzymes involved in the hepatic metabolism/degradation of steroid hormones in the human body: 5α-reductase (SRD5A1) and 5β-reductase (AKR1D1). More exactly, both enzymes are very important in maintaining the androgen-glucocorticoid balance. Thus, any undesired interaction (inhibition) by small molecules (e.g. drugs, cosmetics, food additives, natural compounds) would result in altered activity of the enzymes and potentially lead to disruption of the steroid homeostasis. Increased levels of glucocorticoids may severely affect human health in terms of increased risk for development of metabolic diseases, including diabetes and non-alcoholic fatty liver disease (NAFLD) or non-alcoholic steatohepatosis (NASH) [1-3]. The main goal of this project proposal is to develop in silico predictive models for screening of small molecules in order to rapidly and reliably identify their undesired interaction with the two enzymes. The project requests one year funding for a PhD student who will get training and subsequently apply various state-of-the-art modeling techniques like molecular docking, pose scoring, homology modeling, molecular dynamics simulations to elucidate enzyme-ligand interactions at the atomic level in silico as well as establish experimental activity assays for initial testing and validation of screening hits. The modelling information together with the enzyme activity data will allow defining structure-activity-relationships for the two enzymes. 1. Nasiri M, Nikolaou N, Parajes S, Krone NP, Valsamakis G, Mastorakos G, Hughes B, Taylor A, Bujalska IJ, Gathercole LL, Tomlinson JW: 5α-Reductase Type 2 Regulates Glucocorticoid Action and Metabolic Phenotype in Human Hepatocytes. Endocrinology. 2015, 156(8):2863-71. doi: 10.1210/en.2015-1149. 2. Dowman JK, Hopkins LJ, Reynolds GM, Armstrong MJ, Nasiri M, Nikolaou N, van Houten EL, Visser JA, Morgan SA, Lavery GG, Oprescu A, Hübscher SG, Newsome PN, Tomlinson JW.: Loss of 5α-reductase type 1 accelerates the development of hepatic steatosis but protects against hepatocellular carcinoma in male mice. Endocrinology. 2013, 154(12):4536-47. doi: 10.1210/en.2013-1592. 3. Upreti R, Hughes KA, Livingstone DE, Gray CD, Minns FC, Macfarlane DP, Marshall I, Stewart LH, Walker BR, Andrew R.: 5α-reductase type 1 modulates insulin sensitivity in men. J. Clin. Endocrinol. Metab. 2014, 99(8):E1397-406. doi: 10.1210/jc.2014-1395.
"In vitro" Testung des Potentials endokriner Aktivität von Druckfarbstoffen Research Project | 2 Project MembersA total of 20 food ink chemicals will be tested for potential interferences with the activities of several steroid hormone receptors, including estrogen-, androgen-, progesterone-, mineralocorticoid-, and glucocorticoid receptor. Both agonist and antagonist mode will be assessed. The compounds were selected based on in silico predictions using the Virtual Tox-Lab.
Impact of the NADPH Pool in the Endoplasmic Reticulum on Metabolic and Hormonal Regulation Research Project | 1 Project MembersAn impaired redox control in the endoplasmic reticulum (ER) with unfolded-protein response (UPR) and ER-stress has been associated with major diseases such as cancer, cardio-metabolic disorders, and chronic inflammatory diseases. Thus, it is crucial to elucidate the mechanisms underlying ER-redox control and identify involved modulators and biological reactions. The NAD(P)H/NAD(P) + redox couple is essential for many biological functions and, in contrast to the cytoplasm, its regulation in the ER and the relevance of luminal NADPH for physiological functions such as intracellular calcium signaling, UPR control, and the metabolism of glucose, fatty acids, oxysterols, and glucocorticoids is insufficiently understood. The discovery of hexose-6-phosphate dehydrogenase (H6PDH) revealed a mechanism for luminal NADPH generation and provided a link between energy status and glucocorticoid signaling. To date, 11b-hydroxysteroid dehydrogenase 1 (11b-HSD1) is still the only well characterized NADPH-dependent luminal enzyme. Besides its well-known role in glucocorticoid activation and involvement in metabolic and inflammatory diseases, increasing evidence revealed a role of 11b-HSD1 in oxysterol and bile acid metabolism, warranting further studies. Moreover, there must be other NADPH-dependent enzymes because 11b-HSD1 cannot account for the myopathy and increased susceptibility of hepatocytes toward toxicants observed in situations of H6PDH-deficiency. Based on previous results, we hypothesize that 1) the ratios of certain bile acids serve as potential prognostic markers for decreased 11b-HSD1 activity in rodents and human, 2) 11b-HSD1 is involved in the formation of dihydroxylated oxysterols that modulate the activities of nuclear receptors (ROR, ERβ, LXRβ) and the G-coupled receptor EBI2, 3) H6PDH delivers NADPH for fatty acid elongation in the ER, which is needed for rapid cell proliferation, 4) loss of H6PDH affects UPR and renders cells susceptible to substances causing ER-stress, and 5) other enzymes generating and utilizing NADPH in the ER exist and need to be identified and characterized. To study the consequences of ER NADPH depletion on hormonal and metabolic functions, and to identify and characterize novel modulators of luminal NADPH, we propose to: evaluate whether ratios of certain 7oxo to 7β-hydroxy bile acids in plasma/serum can serve as markers for reduced 11b-HSD1 activity in human, further explore the role of 11b-HSD1 in oxysterol and bile acid metabolism and the modulation of cognate receptors, study other enzymes generating or utilizing NADPH in the ER, study the impact of H6PDH on fatty acid synthesis/metabolism, investigate the impact of H6PDH on breast cancer cell properties, study the susceptibility of H6PDH-deficient primary liver and kidney cells to ER-stress, and explore the use of IP-MS and BioID to investigate protein-protein interactions in the ER. Steroids and other lipophilic compounds in different matrices will be quantified using LC-MS/MS. The role of luminal NADPH and consequences of its depletion on metabolic and hormonal responses will be studied using enzyme preparations, cell-based models upon modulating the corresponding enzyme(s) by overexpression, downregulation by siRNA or pharmacological inhibition. Further, studies in transgenic mice and mice treated with inhibitors and in primary cells will be performed. Also, protein interaction methods will be employed, attempting to identify novel players in ER NADPH regulation. The proposed research should significantly enhance our current knowledge on the role of NADPH in the ER. The expected findings are relevant to understand the coupling between cellular energy state, hormonal regulation, ER redox regulation, and oxidative stress-induced damage. Disturbed functions of the enzymes studied are associated with impaired inflammatory responses, cardio-metabolic disorders and cancer, and the results of the proposed project should support the future development of therapeutic interventions.
Chemicals Disrupting Adrenal Steroidogenesis and/or Peripheral Steroid Action Research Project | 1 Project MembersRationale for the research area An increasing number of chemicals have been suspected of mimicking hormonal effects and altering steroid hormone regulation. Endocrine-disrupting chemicals (EDCs) may contribute to the development and progression of major diseases, including developmental disorders, immune diseases, various forms of cancer and cardio-metabolic diseases such as diabetes, but the mechanisms underlying chemical-induced disruption of endocrine functions are often unknown. Thus, there is a great demand to identify key events of disrupted steroid homeostasis, as well as to develop suitable tools - in vitro and in silico - for early detection of chemical-induced disturbances of steroid homeostasis. Objectives The aim is to generate experimental data that can serve as a basis to improve regulatory test systems for the characterisation of EDCs affecting steroidogenesis and peripheral steroid action. Current regulatory tests for EDCs focus on effects on oestrogen, androgen, and thyroid receptor signalling and on sex steroid production, but do not adequately assess mineralocorticoids, glucocorticoids and adrenal androgens. The proposed project aims to refine the use of the established regulatory cell-based test system (the human adrenal cancer cell line H295R) to characterise effects on these other steroids. Furthermore, effects of EDCs on peripheral steroid action will be investigated by employing computer-based models, biological testing systems and using targeted and untargeted steroid profiling and gene expression analyses. Regulatory Significance Regulatory authorities are participating in large-scale projects on chemical safety, focusing on substances that disrupt endocrine functions; however, the currently available methods and potential targets under investigation are still highly limited, and additional testing strategies are required. The tools to be developed in this project should help in the identification of potentially hazardous chemicals, and the steroidomic profiling should facilitate the investigation of their modes of action and thus risk assessment in humans.
Transcriptomic investigations into drug hypersensitivity towards carboxyllic acid containing compounds Research Project | 2 Project MembersInvestigation of drug adducts in patients treated with carboxylic acid containing compounds
