Radiation promotes acute and chronic damage to adipose tissue
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE295098 | GEO | 2025/05/29
REPOSITORIES: GEO
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Project description:Lipid mobilization (lipolysis) in white adipose tissue (WAT) critically controls lipid turnover and adiposity in humans. While the acute regulation of lipolysis has been studied in detail, the transcriptional determinants of WAT lipolytic activity remain still largely unexplored. Here we show that the genetic inactivation of transcriptional co-factor transducin beta-like-related (TBLR) 1 blunts the lipolytic response of white adipocytes through the impairment of cAMP-dependent signal transduction. Indeed, mice lacking TBLR1 in adipocytes are defective in fasting-induced lipid mobilization and when placed on a high fat diet show aggravated adiposity, glucose intolerance and insulin resistance. TBLR1 levels are found to increase under lipolytic conditions in WAT of both human patients and mice, correlating with serum free fatty acids (FFA). As a critical regulator of WAT cAMP signaling and lipid mobilization, proper activity of TBLR1 in adipocytes may thus represent a critical molecular checkpoint for the prevention of metabolic dysfunction in subjects with obesity-related disorders. We used microarrays to identify global gene expression in 3T3-L1 adipocytes lacking TBLR1 and compared gene expression to control shRNA treated cells in both basal and isoproterenol stimulated states. We analyzed 12 RNA samples extracted from 3T3-L1 adipocytes that were treated with either control or TBLR1 specific shRNAs and with or without 10 µM isoproterenol for 3 hrs. Three replicates of each condition.
2013-04-01 | E-GEOD-43658 | biostudies-arrayexpress
Project description:Background: The radiation bystander response is an important component of the overall response of cells to radiation and critical to understanding health risks of radiation exposure to humans. The mechanism of radiation response includes inter-cellular signaling and intra-cellular communication by which the bystander signal is propagated. Methods: We measured the bystander response to 1Gy a-particle radiation in Mrad9-/- mouse stem cells and H1299shRAD9 cells, using chromosomal aberration and micronucleus formation as DNA damage endpoints. In the H1299 model we used whole genome microarray analyses to profile the transcriptome of irradiated and bystander cells. Results: We investigated the role of RAD9 in the bystander response and showed that depletion or mutation of RAD9 had an effect of increasing chromosomal structural damage as well as micronucleus formation in bystander cells. The enhancement of the damage effect correlated strongly with a transcriptomic response in critical pathways. RAD9 depletion affected many pathways in the cell, including the UV-MAPK pathway, involving p38MAPK members, STAT1 and PARP1 at the mRNA levels. There was an overall reduction of RNA biogenesis of gene members of this pathway suggesting that perhaps these signaling pathways do not function optimally after RAD9 depletion. Using network analysis we found there may be differential activation of transcriptional regulators between the irradiated and bystander cells involving the SP1 and NUPR1 transcription factors. Network analysis also suggested that HIF1a (Hypoxia induced factor 1a) activation could be a negative predictor of the bystander effect and perhaps that local hypoxic stress observed by cells that are directly exposed to radiation may predict whether or not they will elicit a bystander response. Gene expression in H1299 cells was measured at 4 hours after exposure to 1 Gy a-particles. There were two groups based on RAD9 status, RAD9 normal and RAD9 depleted by siRNA. In each of these groups, sham irradiated, direct irradiated cells for positive bystanders, positive bystanders, direct irradiated cells for negative bystanders and negative bystanders; were identified based on micronucleus responses. Five biological replicates were analyzed for each experimental group.
2014-10-07 | E-GEOD-55869 | biostudies-arrayexpress
Project description:Both exposure to ionizing radiation and obesity have been associated with various pathologies including cancer. There is a crucial need in better understanding the interactions between ionizing radiation effects (especially at low doses) and other risk factors, such as obesity. In order to evaluate radiation responses in obese animals, C3H and C57BL/6 mice fed a control low fat or a high fat (HF) diet were exposed to fractionated doses of X-rays (4×0.75 Gy). Bone marrow micronucleus assays did not suggest a modulation of radiation-induced genotoxicity by HF diet. Both HF diet and irradiation resulted in increased oxidative damage, H2AX levels and proliferation in C57BL/6 mouse liver. Using methylation-specific PCR, we observed that the promoters of p16 and Dapk genes were methylated in the livers of C57BL/6 mice fed a HF diet (irradiated and non-irradiated); Mgmt promoter was methylated in irradiated and/or HF diet-fed mice. In addition, methylation PCR arrays identified Ep300 and Socs1 (whose promoters exhibited higher methylation levels in non-irradiated HF diet-fed mice) as potential targets for further studies. We then compared microRNA regulations after radiation exposure in the livers of C57BL/6 mice fed a normal or an HF diet, using microRNA arrays. Interestingly, radiation-triggered microRNA regulations observed in normal mice were not observed in obese mice. All together, our results suggested the existence of dietary effects on radiation responses (especially epigenetic regulations) in mice, possibly in relationship with obesity-induced chronic oxidative stress. C57BL/6J mice were fed a normal or a high-fat diet and exposed to 4 x 0.75 Gy X-rays. miRNA expression was measured in the livers of 3 mice for each experimental group.
2013-11-09 | E-GEOD-47956 | biostudies-arrayexpress
Project description:Radiotherapy, a treatment modality received by more than half of all cancer patients, remains one of the most effective approaches to achieve local tumour control. Despite increased accuracy driven by technological advances, healthy tissue injury due to off-target radiation exposure can still occur. In this study, we sought to understand the biological effect of radiation-mediated injury to the lung in the context of cancer metastasis, since we had previously reported that tissue regeneration is a feature of the metastatic microenvironment of this organ. We have exposed healthy mouse lung tissue to radiation prior to the induction of metastasis and observed a strong enhancement of cancer cell growth. Lung tissue was preconditioned into a profoundly tumour-supportive microenvironment governed by enhanced regenerative Notch signalling. Most importantly, we found that locally activated neutrophils were key drivers of these tissue perturbations, significantly increasing the metastatic proficiency of irradiated lung tissue and endowing arriving cancer cells with an augmented stemness phenotype. We show that by preventing neutrophil-dependent Notch activation in the irradiated tissue, we were able to significantly offset the radiation-enhanced metastases. Mechanistically, we identified the release of neutrophil granules as the effectors of the pro-tumorigenic preconditioning of the irradiated lung tissue. These findings not only reveal a novel tumour-supportive function of neutrophils in the context of tissue-injury, but also have important clinical implications by suggesting targeting their activity could maximise the success of radiotherapy for the treatment of cancer.
2021-12-13 | PXD027628 | Pride
Project description:Both exposure to ionizing radiation and obesity have been associated with various pathologies including cancer. There is a crucial need in better understanding the interactions between ionizing radiation effects (especially at low doses) and other risk factors, such as obesity. In order to evaluate radiation responses in obese animals, C3H and C57BL/6 mice fed a control low fat or a high fat (HF) diet were exposed to fractionated doses of X-rays (4×0.75 Gy). Bone marrow micronucleus assays did not suggest a modulation of radiation-induced genotoxicity by HF diet. Both HF diet and irradiation resulted in increased oxidative damage, H2AX levels and proliferation in C57BL/6 mouse liver. Using methylation-specific PCR, we observed that the promoters of p16 and Dapk genes were methylated in the livers of C57BL/6 mice fed a HF diet (irradiated and non-irradiated); Mgmt promoter was methylated in irradiated and/or HF diet-fed mice. In addition, methylation PCR arrays identified Ep300 and Socs1 (whose promoters exhibited higher methylation levels in non-irradiated HF diet-fed mice) as potential targets for further studies. We then compared microRNA regulations after radiation exposure in the livers of C57BL/6 mice fed a normal or an HF diet, using microRNA arrays. Interestingly, radiation-triggered microRNA regulations observed in normal mice were not observed in obese mice. All together, our results suggested the existence of dietary effects on radiation responses (especially epigenetic regulations) in mice, possibly in relationship with obesity-induced chronic oxidative stress.
2013-11-09 | GSE47956 | GEO
Project description:Lipid mobilization (lipolysis) in white adipose tissue (WAT) critically controls lipid turnover and adiposity in humans. While the acute regulation of lipolysis has been studied in detail, the transcriptional determinants of WAT lipolytic activity remain still largely unexplored. Here we show that the genetic inactivation of transcriptional co-factor transducin beta-like-related (TBLR) 1 blunts the lipolytic response of white adipocytes through the impairment of cAMP-dependent signal transduction. Indeed, mice lacking TBLR1 in adipocytes are defective in fasting-induced lipid mobilization and when placed on a high fat diet show aggravated adiposity, glucose intolerance and insulin resistance. TBLR1 levels are found to increase under lipolytic conditions in WAT of both human patients and mice, correlating with serum free fatty acids (FFA). As a critical regulator of WAT cAMP signaling and lipid mobilization, proper activity of TBLR1 in adipocytes may thus represent a critical molecular checkpoint for the prevention of metabolic dysfunction in subjects with obesity-related disorders. We used microarrays to identify global gene expression in 3T3-L1 adipocytes lacking TBLR1 and compared gene expression to control shRNA treated cells in both basal and isoproterenol stimulated states.
2013-04-01 | GSE43658 | GEO
Project description:The circadian clock is a cell-autonomous transcription-translation feedback mechanism that anticipates and adapts physiology and behavior to different phases of the day. A variety of factors including hormones, temperature, food-intake, and exercise can act on tissue-specific peripheral clocks to alter the expression of genes that influence metabolism, all in a time-of-day dependent manner. The aim of this study was to elucidate the effects of exercise timing on adipose tissue metabolism. We performed RNA sequencing on inguinal adipose tissue of mice immediately following maximal exercise or sham treatment at the early rest or early active phase. Only during the early active phase did exercise elicit an immediate increase in serum non-esterified fatty acids. Furthermore, early active phase exercise increased expression of markers of thermogenesis and mitochondrial proliferation in inguinal adipose tissue. In vitro, synchronized 3T3-L1 adipocytes showed a timing-dependent difference in Adrb2 expression, as well as a greater lipolytic activity. Thus, the response of adipose tissue to exercise is time- of-day sensitive and may be partly driven by the circadian clock. To determine the influence of feeding state on the time-of-day response to exercise, we replicated the experiment in 10- hour-fasted early rest phase mice to mimic the early active phase metabolic status. A 10-hour fast led to a similar lipolytic response as observed after active phase exercise, but did not replicate the transcriptomic response, suggesting that the observed changes in gene expression are not driven by feeding status. In conclusion, acute exercise elicits timing-specific effects on adipose tissue to maintain metabolic homeostasis.
2023-01-19 | GSE199429 | GEO
Project description:Objective:Biomarkers of radiation injury are needed in planning therapeutic measures for cancer patients receiving radiation therapy and civilians exposed to nuclear events. Previous research has highlighted the impact of radiation damage, with cancer patients developing acute disorders including radiation induced pneumonitis or chronic disorders including pulmonary fibrosis months after radiation therapy ends. Discovery of biomarkers that predict these injuries will offer the potential to treat people proactively to mitigate this damage and improve quality of life. Recent research has highlighted the potential for messenger RNA (mRNA), microRNA (miRNA), and long non-coding RNA (lncRNA) to be used as radiation biomarkers. Our study focused on the changes in these RNAs at 48h after radiation exposure of mouse lung tissue to define biological pathway changes and determine potential biomarkers. Result: We observed sustained dysregulation of specific mRNAs, lncRNAs, and miRNAs across all doses. We observed gene dysregulation which can be used to develop both markers to identify no-exposure vs radiation exposure including Hba and Hbb mRNA which were dysregulated even at 1 Gy. We also observed genes which can indicate high dose exposure including Cpt1c and Pdk4. Gdf15, and Eda2r, mRNA markers of senescence and fibrosis, were the most significantly upregulated. Only three miRNAs were significantly dysregulated across all radiation doses, with miRNA-142-3p and miRNA-142-5p downregulated and miRNA-34a-5p upregulated. IPA analysis indicated that numerous pathways relevant to immune function, cell proliferation and survival decreased with increasing doses of radiation. This data highlighted early pathways of dysregulation depending on dose of exposure. This data will help with development of treatments and in medical decision-making. Further experiments are planned to develop medical countermeasures based on this early dysregulation.
2022-06-06 | GSE202586 | GEO
Project description:Obesity is considered an important factor for many chronic diseases, including diabetes, cardiovascular disease and cancer. The expansion of adipose tissue in obesity is due to an increase in both adipocyte progenitor differentiation and mature adipocyte cell size. Adipocytes, however, are thought to be unable to divide or enter cell cycle. We demonstrate that mature human adipocytes unexpectedly display a gene and protein signature of cell cycle re-entry. Adipocyte cell cycle progression associates with obesity and hyperinsulinemia, with a concomitant increase in cell size, nuclear size and nuclear DNA content. However, chronic hyperinsulinemia in vitro or in patients, is associated with subsequent cell cycle exit, leading to a premature senescent transcriptomic and secretory profile in adipocytes. Premature senescence is rapidly becoming recognized as an important mediator of stress-induced tissue dysfunction. By demonstrating that adipocytes can re-enter cell cycle we define a mechanism for how mature, human adipocytes senesce and demonstrate that by targeting the adipocyte cell cycle program it is possible to impact adipocyte senescence and obesity-associated adipose tissue inflammation.
| EGAS00001005770 | EGA
Project description:White adipose tissue (WAT) is a central factor in the development of type 2 diabetes. Despite the epidemiological importance of WAT there is a paucity of translational models to study long term changes in mature adipocytes. Here, we describe a novel method for the culture of mature white adipocytes under a permeable membrane. Compared to existing culture methods such as adipose tissue explants and adipocyte ceiling culture, Membrane mature Adipocyte Aggregate Cultures (MAAC) are superior at maintaining adipogenic gene expression through 2 weeks of culture, do not dedifferentiate, and are under reduced hypoxic stress relative to adipose tissue explants. Unbiased RNA-Sequencing analysis indicates that the gene expression profile of MAAC in culture for 1 or 2 weeks is more similar to starting patient material than cultured adipose tissue explants, floating adipocytes, or in vitro-differentiated precursors from the same donor, with the fewest number of differentially expressed genes and the smallest fold-change in gene expression. Importantly, adipocytes from lean and obese patients can be cultured as MAAC, as can subcutaneous and visceral adipocytes, while maintaining depot-specific gene expression signatures. MAAC remain fully functional after long term culture, with similar responses to insulin and lipolytic stimuli compared to recently isolated cells. In addition, MAAC maintain the ability to crosstalk with other cell types, producing synergistic increases in IL6 and IL8 when co-cultured with macrophages, and respond robustly and predictably to diverse pharmacological agonism. Together, these abilities make MAAC a powerful tool for studying phenotypic changes in mature adipocytes, crosstalk between adipocytes and other cell types, and provide an improved translational model for drug development for the modulation of adipose tissue function.
2019-04-02 | GSE115020 | GEO