Molecular genomic studies of the obesogenic effects of tributyltin during adipogenic differentiation implicate a primary role for cytoskeletal damage [RNA-seq]
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE207038 | GEO | 2024/01/01
REPOSITORIES: GEO
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Project description:Environmental obesogens are being studied for their potential role in the increasing prevalence of obesity globally. A major area of focus in this field of research has been on the mechanism by which these agents act. In this study we focused on the organotin tributyltin (TBT), a water pollutant exposed to humans through diet. The mechanism by which TBT is believed to act is by binding to the PPAR nuclear receptor which heterodimerizes with RXR to alter gene regulation. To test whether this was the dominant mechanism for TBT activity, we performed time-course studies of transcription and chromatin accessibility in mesenchymal stem cells differentiating to adipocytes. We found limited evidence for PPAR effects by TBT, but a strong response by Ras-related GTPases and evidence for the loss of TEAD transcription factor activity during differentiation. These observations combine to implicate a known property of organotins, to cause cytoskeletal depolymerization. We propose a model for TBT activity involving a primary effect of cytoskeletal damage, leading to the loss of YAP co-regulator activity and the consequent failure of TEAD repression of adipogenesis.
2024-01-01 | GSE207039 | GEO
Project description:Organotin compounds are highly persistent organic pollutants that bioaccumulate in marine biota, behaving as potent endocrine disruptors. Tributyltin (TBT) has been described as an environmental obesogen, as it contributes in mammals to lipid accumulation in a mechanism mediated by PPARγ and RXR. With the aim of studying the molecular mechanisms that elicit TBT-induced pathogenesis in fish, thicklip grey mullets Chelon labrosus were exposed to low (10 ng/L) and high (500 ng/L) TBT concentrations for 1, 7 and 21 days, and gene transcription and metabolome profiles were studied. With this purpose, the multitissue transcriptome of mullet was sequenced by 454 pyrosequencing obtaining 126 Mb of sequence information. Assembly and annotation allowed spotting 8330 gene signatures on an oligonucleotide microarray that was used to identify hepatic gene transcription profiles specific to each TBT exposure set-up. Functional pathway analysis revealed that early profiles were characterized by genes related to response to organic substances and to oxidative stress and glucose metabolic processes. After 21 days of exposure, enriched GO terms in both concentrations were related to lipid homeostasis with a significant regulation of steroid metabolic and cholesterol biosynthetic processes. Also, the androgen receptor signalling pathway was regulated while PPAR signalling appeared as the most significantly regulated KEGG pathway. Neutral lipid accumulation measured by Oil-Red-O histochemistry did not show any treatment-related effect but hepatic and plasma NMR and GC-MS metabolomic analysis revealed distinctive metabolites. Aqueous profiles were characterised by lactate, glucose and alanine while GC-MS revealed a whole set of discriminating polyunsaturated fatty acids. Thus, TBT pathogenesis involves alterations of lipid metabolism through a mechanism that could involve PPARγ-regulated processes confirming the obesogen hypothesis for TBT in fish. Thicklip grey mullets were exposed to tributyltin (TBT). 3 treatments: control, TBT low dose (10ng/L), TBT high dose (500ng/L); 3 sampling times: 1 day, 1 week, 3 weeks. 6 mullets were dissected in each sampling point and group.
2016-07-31 | E-GEOD-36811 | biostudies-arrayexpress
Project description:Organotin compounds are highly persistent organic pollutants that bioaccumulate in marine biota, behaving as potent endocrine disruptors. Tributyltin (TBT) has been described as an environmental obesogen, as it contributes in mammals to lipid accumulation in a mechanism mediated by PPARγ and RXR. With the aim of studying the molecular mechanisms that elicit TBT-induced pathogenesis in fish, thicklip grey mullets Chelon labrosus were exposed to low (10 ng/L) and high (500 ng/L) TBT concentrations for 1, 7 and 21 days, and gene transcription and metabolome profiles were studied. With this purpose, the multitissue transcriptome of mullet was sequenced by 454 pyrosequencing obtaining 126 Mb of sequence information. Assembly and annotation allowed spotting 8330 gene signatures on an oligonucleotide microarray that was used to identify hepatic gene transcription profiles specific to each TBT exposure set-up. Functional pathway analysis revealed that early profiles were characterized by genes related to response to organic substances and to oxidative stress and glucose metabolic processes. After 21 days of exposure, enriched GO terms in both concentrations were related to lipid homeostasis with a significant regulation of steroid metabolic and cholesterol biosynthetic processes. Also, the androgen receptor signalling pathway was regulated while PPAR signalling appeared as the most significantly regulated KEGG pathway. Neutral lipid accumulation measured by Oil-Red-O histochemistry did not show any treatment-related effect but hepatic and plasma NMR and GC-MS metabolomic analysis revealed distinctive metabolites. Aqueous profiles were characterised by lactate, glucose and alanine while GC-MS revealed a whole set of discriminating polyunsaturated fatty acids. Thus, TBT pathogenesis involves alterations of lipid metabolism through a mechanism that could involve PPARγ-regulated processes confirming the obesogen hypothesis for TBT in fish.
2016-07-31 | GSE36811 | GEO
Project description:The obesogen hypothesis states that exposure to environmental compounds early in life or throughout lifetime might have an influence on obesity development. In this paper a new approach for obesogen screening is proposed, namely the use of transcriptomics in the 3T3-L1 pre-adipocyte cell line. Based on the data from a previous study of our group using a lipid accumulation based adipocyte differentiation assay, several humanly relevant obesogenic compounds were selected: reference obesogens [Rosiglitazone (ROSI), Tributyltin (TBT)], test obesogens [Butylbenzyl phthalate (BBP), butylparaben (BP), propylparaben (PP), Bisphenol A (BPA)] and non-obesogens [Ethylene Brassylate (EB), Bis (2-ethylhexyl)phthalate (DEHP)]. In this paper, the high stability and reproducibility of the 3T3-L1 gene transcription patterns over different experiments and cell batches was shown. Obesogens and non-obesogen gene transcription profiles were clearly distinguished using hierarchical clustering. Furthermore, a gradual distinction corresponding to differences in induction of lipid accumulation could be made between test and reference obesogens based on transcription patterns, indicating the potential use of this strategy for classification of obesogens. Marker genes that are able to distinguish between non, test and reference obesogens were identified. Well known genes involved in adipocyte differentiation, as well as genes with unknown functions were selected, implying a potential adipocyte related function of the latter. Cell physiological lipid accumulation was well predicted based on transcription levels of the marker genes, indicating the biological relevance of omics data. In conclusion, this study shows the high relevance and reproducibility of this 3T3-L1 based in vitro toxicogenomics tool for classification of obesogens and biomarker discovery. The hybridization design was a reference design (reference sample was a mixture of equal aliquots from control and exposed samples), recommended for class discovery purposes (Knapen et al. 2009). The reference sample was labeled with Cy5, and the exposed samples with Cy3. Three biological replicates were measured for every condition.
2014-05-01 | E-GEOD-53004 | biostudies-arrayexpress
Project description:Obesogens such as tributyltin (TBT) are xenobiotic compounds that promote obesity, in part by distorting the normal balance of lipid metabolism. The obesogenic effects of TBT can be observed in directly exposed (F1 and F2 generations) and also subsequent generations (F3 and beyond) that were never exposed. To address the effects of TBT exposure on germ cells, we exposed pregnant transgenic OG2 mouse dams (F0), which specifically express EGFP in germline cells, to an environmentally relevant dose of TBT throughout gestation through drinking water. When fed with a high fat diet (HFD), F3 male offspring of TBT-exposed F0 dams (TBT-F3) accumulated much more body fat than did Control-F3 males. TBT-F3 males also lost more body fluid and lean compositions than did Control-F3 males. Expression of genes involved in transcriptional regulation or mesenchymal differ-entiation was upregulated in somatic cells of TBT-F1 (but not TBT-F3) E18.5 fetal testes, and promoter-associated CpG islands were hyper-methylated in TBT-F1 somatic cells. Global mRNA expression of protein-coding genes in F1 or F3 fetal testicular cells was unaffected by F0 exposure to TBT; however, expression of a subset of endogenous retroviruses was significantly affected in F1 and F3. We infer that TBT may directly target testicular somatic cells in F1 testes to irreversibly affect epigenetic suppression of endogenous retroviruses in both germline and somatic cells.
2022-03-02 | GSE191199 | GEO
Project description:The obesogen hypothesis states that exposure to environmental compounds early in life or throughout lifetime might have an influence on obesity development. In this paper a new approach for obesogen screening is proposed, namely the use of transcriptomics in the 3T3-L1 pre-adipocyte cell line. Based on the data from a previous study of our group using a lipid accumulation based adipocyte differentiation assay, several humanly relevant obesogenic compounds were selected: reference obesogens [Rosiglitazone (ROSI), Tributyltin (TBT)], test obesogens [Butylbenzyl phthalate (BBP), butylparaben (BP), propylparaben (PP), Bisphenol A (BPA)] and non-obesogens [Ethylene Brassylate (EB), Bis (2-ethylhexyl)phthalate (DEHP)]. In this paper, the high stability and reproducibility of the 3T3-L1 gene transcription patterns over different experiments and cell batches was shown. Obesogens and non-obesogen gene transcription profiles were clearly distinguished using hierarchical clustering. Furthermore, a gradual distinction corresponding to differences in induction of lipid accumulation could be made between test and reference obesogens based on transcription patterns, indicating the potential use of this strategy for classification of obesogens. Marker genes that are able to distinguish between non, test and reference obesogens were identified. Well known genes involved in adipocyte differentiation, as well as genes with unknown functions were selected, implying a potential adipocyte related function of the latter. Cell physiological lipid accumulation was well predicted based on transcription levels of the marker genes, indicating the biological relevance of omics data. In conclusion, this study shows the high relevance and reproducibility of this 3T3-L1 based in vitro toxicogenomics tool for classification of obesogens and biomarker discovery.
2014-05-01 | GSE53004 | GEO
Project description:Obesogenic compounds are chemicals that might have an influence on obesity development through in utero or chronic lifetime exposure. Tributyltin (TBT) is one of the most studied obesogenic compounds, inducing adipogenesis in vitro and increasing body fat after in utero exposure of mice. This study was designed to unravel the molecular mechanisms of TBT, using microarray analysis, and to evaluate the use of toxicogenomics for obesogen screening. The murine 3T3-L1 cell line was used to study TBT induced adipogenesis. Lipid staining as well as gene expression measurements of an adipocyte specific marker gene were performed to select relevant concentrations (10 nM, 50 nM) and time points (day1, day10) for microarray analysis. Additionally, solvent control and positive control (MDI) treated 3T3-L1 cells were included in the analysis. The microarray results were analysed using GO enrichment and Pathway analysis tools, which revealed enrichment of several GO terms involved in energy and fat metabolism after 10 days of TBT exposure. Pathway analysis unveiled PPAR signalling pathway as the sole pathway significantly enriched after 1 day and the most significantly enriched pathway after 10 days of exposure. By examination of effects on both cell physiological and gene expression level we provide a detailed overview of TBT induced obesogenic mechanisms. To our knowledge, this is the first study delivering an in depth mechanistic outline of the mode of action of TBT as an obesogen. Furthermore, our results show that combining omics with 3T3-L1 cells is promising for screening of potential obesogenic compounds. A separate v+2 A-optimal hybridization design was used for each time-point. Using this design each exposure condition is represented by three biological replicates, with each biological replicate analysed in technical duplicate while applying the dye swap principle to correct for dye bias. Two concentrations of TBT (10 nM, 50 nM), DMSO and MDI (positive control, adipogenic hormone cocktail) were the conditions tested, at two time-points (day 1 and day10).
2013-02-25 | E-GEOD-41340 | biostudies-arrayexpress
Project description:Obesogenic compounds are chemicals that might have an influence on obesity development through in utero or chronic lifetime exposure. Tributyltin (TBT) is one of the most studied obesogenic compounds, inducing adipogenesis in vitro and increasing body fat after in utero exposure of mice. This study was designed to unravel the molecular mechanisms of TBT, using microarray analysis, and to evaluate the use of toxicogenomics for obesogen screening. The murine 3T3-L1 cell line was used to study TBT induced adipogenesis. Lipid staining as well as gene expression measurements of an adipocyte specific marker gene were performed to select relevant concentrations (10 nM, 50 nM) and time points (day1, day10) for microarray analysis. Additionally, solvent control and positive control (MDI) treated 3T3-L1 cells were included in the analysis. The microarray results were analysed using GO enrichment and Pathway analysis tools, which revealed enrichment of several GO terms involved in energy and fat metabolism after 10 days of TBT exposure. Pathway analysis unveiled PPAR signalling pathway as the sole pathway significantly enriched after 1 day and the most significantly enriched pathway after 10 days of exposure. By examination of effects on both cell physiological and gene expression level we provide a detailed overview of TBT induced obesogenic mechanisms. To our knowledge, this is the first study delivering an in depth mechanistic outline of the mode of action of TBT as an obesogen. Furthermore, our results show that combining omics with 3T3-L1 cells is promising for screening of potential obesogenic compounds.
2013-02-25 | GSE41340 | GEO
Project description:Cardiac hypertrophy is characterized by increase in the size of the cardiomyocytes which is initially triggered as an adaptive response due to various kinds of stimuli but ultimately becomes maladaptive with chronic exposure. Peroxisome proliferator activated receptor alpha (PPAR α), which is critical for mitochondrial biogenesis and fatty acid oxidation, is known to be down regulated in hypertrophied cardiomyocytes. The aim of the study was to unveil the role of PPAR α in the mechanism that drives myocardium towards maladaptation in chronic hypertrophy. Wild-type C57BL/6 and PPAR α-/- mice were subjected to isoproterenol treatment for 2 weeks (n=8). Proteomic analysis using Orbitrap mass spectrometer revealed an unexpected down regulation of apoptotic markers, Annexin V and p53. PPAR α regulated and non-regulated genes were validated using RT-PCR. Specificity for α isoform was confirmed using PPAR α agonist, fenofibrate and pan-agonist bezafibrate. Fenofibrate failed to restore PPAR α target genes, whereas bezafibrate managed to ameliorate the effects of isoproterenol for a subset of genes even in the absence of PPAR α. Autophagy markers like p62, Beclin1 and LC3 A/B were up regulated in PPAR α-/-mice therefore indicating an upsurge in autophagy. The results demonstrate hindrance to intrinsic apoptotic pathway and activation of autophagy in the absence of PPAR α in hypertrophic cardiomyocytes. Therefore, PPAR α signalling might act as a molecular switch between apoptosis and autophagy thereby playing a critical role in adaptive process in stress induced cardiomyocytes.
2022-04-04 | PXD025470 | Pride
Project description:The transcriptional coactivators YAP/TAZ are the critical downstream regulators of the Hippo pathway that regulate gene expression in response to changes in pathway activity, mainly by binding to TEAD transcription factors. Uncontrolled transcriptional output of YAP/TAZ can lead to rapid induction of aggressive tumor growth. AP-1 is a dimeric basic leucine zipper (bZIP) transcription factor complex with JUN and FOS proteins being the most abundant members of this family. Unlike FOS, JUN can also form homodimers, but in the cell, JUN presumably preferentially forms heterodimers with members of the FOS family, which act as potent transcriptional activators. Previous studies identified substantial co-occupancy of YAP/TAZ and AP-1 at genomic sites, and they demonstrated that JUN/FOS heterodimers cooperate with the YAP/TAZ and TEAD transcription factors to drive YAP/TAZ target gene expression. Here, we now elucidate a negative feedback mechanism in which high YAP activity is restrained by the recruitment of homodimeric JUN::JUN/NCOR1 repressor complexes and show that this noncanonical JUN function is part of a tumor suppressor mechanism in the liver.
2024-06-30 | GSE235960 | GEO