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An integrative omics approach to unravel the obesogenic mode of action of tributyltin
S50
Abstracts / Comparative Biochemistry and Physiology, Part A 163 (2012) S48–S54
6. Added value of in vitro mechanistic information in environmental risk assessment. I. Nobels, C. Vanparys, F. Dardenne, R. Blust (Biology, University of Antwerp, Belgium) Whole organism tests are an important cornerstone in environmental risk assessment (ERA) since they provide information on important endpoints such as effects on survival, growth and reproduction and take into account the bioavailability and the possible interactions between multiple pollutants. In recent years more attention is paid to mechanistic information obtained at lower levels (cellular or tissue) of biological organisation to better understand how chemicals interact with a biological system and to detect possible effects or risks related to the exposure in an early phase of development. The use of specifically designed in vitro systems can offer a suitable and relatively easy to perform platform to obtain more detailed mechanistic information concerning the effects of pollutants on biological systems and provide an added value in risk assessment. In this presentation, several case studies based on an in vitro bacterial reporter assay will be discussed that reflect the ecotoxicological relevance of mechanistic information. The used Escherichia coli based reporter assay consists of a selection of genetically modified strains responding to different types of stress like DNA damage, oxidative stress, protein denaturation, membrane damage, osmotic stress and general cellular stress. Important progress was made towards the toxicological characterisation of a high number of individual compounds (perfluorinated compounds, pesticides, anilines and adjuvants) and mixtures (pesticide formulations). The information obtained was used to categorise compounds according to their principal toxic mode of action in order to improve read across. Furthermore, the obtained gene expression profiles were used to prioritize compounds for targeted in vivo testing. Finally, for a subset of the database (38 pesticides) bacterial gene expression profiles were combined to publically available aquatic toxicity studies (acute and chronic). The results showed that the obtained mechanistic information enhanced the interpretation of the in vivo results. Nevertheless, the used bacterial reporter assay has its limitations as it is less sensitive than in vivo assays and cannot detect specific modes of action like endocrine disruption. In conclusion we can state that the combination of reduced in vivo experiments and in vitro toxic mode of action information provides a more solid base for ERA. doi:10.1016/j.cbpa.2012.05.146
7. Long-term genotoxic and carcinogenic potential of CuO nanoparticles on mussels A. Katsumiti, P. Ruiz, J. Bori, J.A. Nieto (CBET Research Group, University of the Basque Country UPV/EHU, Basque Country, Spain); P. Reip (Intrinsiq Materials, Farnborough, UK); A. Orbea, M.P. Cajaraville (CBET Research Group, University of the Basque Country UPV/EHU, Basque Country, Spain) CuO nanoparticles (NPs) are commonly used as bacteriocides, additives in lubricants, coating, inks, etc. but their toxic effects in wildlife (especially after long-term exposure) are still not well understood. Oxidative stress has been proposed as one of the main mechanisms of NPs’ toxicity and is considered a non-genotoxic mechanism of carcinogenesis. Thus, the purpose of the present work was to study the long-term effects of CuO NPs on mussel antioxidant activities (catalase — CAT, glutathione peroxidase — GPx and superoxide dismutase — SOD), micronuclei (MN) frequency, histopathology and transcription levels of cancer-related genes (ras, gadd45α and p53). Mussels were exposed for 21 days to CuO NPs,
bulk CuO and ionic Cu, and then kept for up to 122 days in clean water for recovery. Exposure to CuO NPs for 1 day caused a significant induction of CAT and GPx in the digestive gland (DG). The same was observed for bulk CuO for CAT, SOD and GPx in the DG and CAT in gills. Ionic Cu also induced CAT and GPx in the DG and SOD in gills. At 21 days exposure to CuO NPs, CAT and SOD were induced further in the DG. MN frequency was significantly higher in mussels exposed to CuO NPs for 21 days compared to controls and to mussels in the recovery period. Disseminated neoplasia was found in one organism treated with CuO NPs but overall, the prevalence of histopathological alterations did not vary with the treatments. The transcription level of ras and gadd45α did not show significant variations neither among treatments nor among time periods. For p53, significant differences in transcription level were only recorded in control animals along the recovery period. In conclusion, all forms of Cu altered antioxidant enzyme activities and produced genotoxic effects after 21 days exposure but no clear relation between CuO NP exposure and cancer development can be concluded. This research was funded by EU 7th FP (project NanoReTox, ref CP-FP 214478‐2), Spanish Ministry of Science and Innovation (project NanoCancer CTM2009-13477 and PhD grant to PR), UPV/EHU (UFI11/37) and Basque Government (consolidated research group GIC07/26-IT-393-07). doi:10.1016/j.cbpa.2012.05.147
8. An integrative omics approach to unravel the obesogenic mode of action of tributyltin A. Pereira-Fernandes, C. Vanparys, T. Hectors, R. Blust Biology, University of Antwerp, Belgium)
(Dept. of
Obesity is defined as a disease in which excessive body fat accumulation causes adverse effects on health, leading to a higher morbidity and mortality. An excessive caloric intake and a lack of physical activity together with genetic predisposition are pointed out as major causes of obesity development. However, recently independent laboratories showed the potential influence of exposure to endocrine disrupting compounds on obesity development. Tributyltin (TBT) is one of the most studied obesogenic compounds, with the induction of adipocyte differentiation in vitro, but also an increased body fat after in utero exposure of mice. However, a detailed mechanistic study to unravel the mode of action of TBT is still lacking. In this project mouse and human in vitro pre-adipocyte cell lines are being used for the mechanistic study of obesogenic compounds. These cells are fibroblastic cells that can differentiate into mature adipocytes when exposed to a cocktail of adipogenic compounds, making it possible to test the effect of endocrine disrupting compounds on adipocyte differentiation. The goal of this study is twofold: i) integrative study of transcriptomic and proteomic data leading to an in depth knowledge of the obesogenic effect of TBT and ii) interspecies comparison of the obesogenic mode of action using data from mouse and human adipocytes. Our transcriptomic data of TBT exposed pre-adipocytes showed interesting results. GO classes involved in energy metabolism were significantly enriched after 10 days of exposure. Pathway analysis confirmed the already described importance of PPAR signaling in TBT induced adipogenesis. To further enlarge our knowledge on the mode of action of TBT, proteomic analysis will be done on both human and mouse cell systems. With this study we will be the first to evaluate the interspecies differences of the obesogenic mode of action of TBT and to unravel the detailed mode of action of TBT using an integrative omics approach.
doi:10.1016/j.cbpa.2012.05.148
Abstracts / Comparative Biochemistry and Physiology, Part A 163 (2012) S48–S54
6. Added value of in vitro mechanistic information in environmental risk assessment. I. Nobels, C. Vanparys, F. Dardenne, R. Blust (Biology, University of Antwerp, Belgium) Whole organism tests are an important cornerstone in environmental risk assessment (ERA) since they provide information on important endpoints such as effects on survival, growth and reproduction and take into account the bioavailability and the possible interactions between multiple pollutants. In recent years more attention is paid to mechanistic information obtained at lower levels (cellular or tissue) of biological organisation to better understand how chemicals interact with a biological system and to detect possible effects or risks related to the exposure in an early phase of development. The use of specifically designed in vitro systems can offer a suitable and relatively easy to perform platform to obtain more detailed mechanistic information concerning the effects of pollutants on biological systems and provide an added value in risk assessment. In this presentation, several case studies based on an in vitro bacterial reporter assay will be discussed that reflect the ecotoxicological relevance of mechanistic information. The used Escherichia coli based reporter assay consists of a selection of genetically modified strains responding to different types of stress like DNA damage, oxidative stress, protein denaturation, membrane damage, osmotic stress and general cellular stress. Important progress was made towards the toxicological characterisation of a high number of individual compounds (perfluorinated compounds, pesticides, anilines and adjuvants) and mixtures (pesticide formulations). The information obtained was used to categorise compounds according to their principal toxic mode of action in order to improve read across. Furthermore, the obtained gene expression profiles were used to prioritize compounds for targeted in vivo testing. Finally, for a subset of the database (38 pesticides) bacterial gene expression profiles were combined to publically available aquatic toxicity studies (acute and chronic). The results showed that the obtained mechanistic information enhanced the interpretation of the in vivo results. Nevertheless, the used bacterial reporter assay has its limitations as it is less sensitive than in vivo assays and cannot detect specific modes of action like endocrine disruption. In conclusion we can state that the combination of reduced in vivo experiments and in vitro toxic mode of action information provides a more solid base for ERA. doi:10.1016/j.cbpa.2012.05.146
7. Long-term genotoxic and carcinogenic potential of CuO nanoparticles on mussels A. Katsumiti, P. Ruiz, J. Bori, J.A. Nieto (CBET Research Group, University of the Basque Country UPV/EHU, Basque Country, Spain); P. Reip (Intrinsiq Materials, Farnborough, UK); A. Orbea, M.P. Cajaraville (CBET Research Group, University of the Basque Country UPV/EHU, Basque Country, Spain) CuO nanoparticles (NPs) are commonly used as bacteriocides, additives in lubricants, coating, inks, etc. but their toxic effects in wildlife (especially after long-term exposure) are still not well understood. Oxidative stress has been proposed as one of the main mechanisms of NPs’ toxicity and is considered a non-genotoxic mechanism of carcinogenesis. Thus, the purpose of the present work was to study the long-term effects of CuO NPs on mussel antioxidant activities (catalase — CAT, glutathione peroxidase — GPx and superoxide dismutase — SOD), micronuclei (MN) frequency, histopathology and transcription levels of cancer-related genes (ras, gadd45α and p53). Mussels were exposed for 21 days to CuO NPs,
bulk CuO and ionic Cu, and then kept for up to 122 days in clean water for recovery. Exposure to CuO NPs for 1 day caused a significant induction of CAT and GPx in the digestive gland (DG). The same was observed for bulk CuO for CAT, SOD and GPx in the DG and CAT in gills. Ionic Cu also induced CAT and GPx in the DG and SOD in gills. At 21 days exposure to CuO NPs, CAT and SOD were induced further in the DG. MN frequency was significantly higher in mussels exposed to CuO NPs for 21 days compared to controls and to mussels in the recovery period. Disseminated neoplasia was found in one organism treated with CuO NPs but overall, the prevalence of histopathological alterations did not vary with the treatments. The transcription level of ras and gadd45α did not show significant variations neither among treatments nor among time periods. For p53, significant differences in transcription level were only recorded in control animals along the recovery period. In conclusion, all forms of Cu altered antioxidant enzyme activities and produced genotoxic effects after 21 days exposure but no clear relation between CuO NP exposure and cancer development can be concluded. This research was funded by EU 7th FP (project NanoReTox, ref CP-FP 214478‐2), Spanish Ministry of Science and Innovation (project NanoCancer CTM2009-13477 and PhD grant to PR), UPV/EHU (UFI11/37) and Basque Government (consolidated research group GIC07/26-IT-393-07). doi:10.1016/j.cbpa.2012.05.147
8. An integrative omics approach to unravel the obesogenic mode of action of tributyltin A. Pereira-Fernandes, C. Vanparys, T. Hectors, R. Blust Biology, University of Antwerp, Belgium)
(Dept. of
Obesity is defined as a disease in which excessive body fat accumulation causes adverse effects on health, leading to a higher morbidity and mortality. An excessive caloric intake and a lack of physical activity together with genetic predisposition are pointed out as major causes of obesity development. However, recently independent laboratories showed the potential influence of exposure to endocrine disrupting compounds on obesity development. Tributyltin (TBT) is one of the most studied obesogenic compounds, with the induction of adipocyte differentiation in vitro, but also an increased body fat after in utero exposure of mice. However, a detailed mechanistic study to unravel the mode of action of TBT is still lacking. In this project mouse and human in vitro pre-adipocyte cell lines are being used for the mechanistic study of obesogenic compounds. These cells are fibroblastic cells that can differentiate into mature adipocytes when exposed to a cocktail of adipogenic compounds, making it possible to test the effect of endocrine disrupting compounds on adipocyte differentiation. The goal of this study is twofold: i) integrative study of transcriptomic and proteomic data leading to an in depth knowledge of the obesogenic effect of TBT and ii) interspecies comparison of the obesogenic mode of action using data from mouse and human adipocytes. Our transcriptomic data of TBT exposed pre-adipocytes showed interesting results. GO classes involved in energy metabolism were significantly enriched after 10 days of exposure. Pathway analysis confirmed the already described importance of PPAR signaling in TBT induced adipogenesis. To further enlarge our knowledge on the mode of action of TBT, proteomic analysis will be done on both human and mouse cell systems. With this study we will be the first to evaluate the interspecies differences of the obesogenic mode of action of TBT and to unravel the detailed mode of action of TBT using an integrative omics approach.
doi:10.1016/j.cbpa.2012.05.148