Project description:The CCR4-NOT deadenylase complex has a critical function to trigger mRNA decay and various biological events. To understand roles of the complex in adipocyte function, we compare mRNA half-lives between control and Cnot complex-deficient mature adipocytes from iWAT and BAT.
Project description:The CCR4-NOT dedadenylase complex is essential for mRNA decay and various biological events.To understand roles of the complex in mouse embryonic fibroblasts, we compared mRNA half-lives between control and Cnot complex-deficient mouse embryonic fibroblasts
Project description:We took a systematic approach to determine the transcriptional programs that are specifically regulated by C/EBPα in mature white adipocytes of mice on chow diet or high fat diet. The hypothesis tested in the present study was that C/EBPα, as a lipogenic transcription factor, has unique direct targets compared to PPARγ. Our inducible adipocyte specific knockout system allows us to test the direct targets of C/EBPα and PPARγ in adipocytes by short-term C/EBPα or PPARγ elimination in mature adipocytes in vivo. Results indicate that although it has been shown that C/EBPα and PPARγ cross-regulate each other, they have distinct direct responsive targets. Moreover, there are very few C/EBPα specific targets in mice on a chow diet, most of the C/EBPα targets in mature adipocytes are genes modulated by HFD feeding.
Project description:We took a systematic approach to determine the transcriptional programs that are specifically regulated by C/EBP? in mature white adipocytes of mice on chow diet or high fat diet. The hypothesis tested in the present study was that C/EBP?, as a lipogenic transcription factor, has unique direct targets compared to PPAR?. Our inducible adipocyte specific knockout system allows us to test the direct targets of C/EBP? and PPAR? in adipocytes by short-term C/EBP? or PPAR? elimination in mature adipocytes in vivo. Results indicate that although it has been shown that C/EBP? and PPAR? cross-regulate each other, they have distinct direct responsive targets. Moreover, there are very few C/EBP? specific targets in mice on a chow diet, most of the C/EBP? targets in mature adipocytes are genes modulated by HFD feeding. Total RNA obtained from subcutaneous adipose tissue of Adn-C/EBP?-/- mice on doxycycline chow diet for 3 days, doxycycline high fat diet for 3 days or 1 month and Adn-PPAR?-/- mice on doxycycline chow diet for 3 days, compared to control littermates.
Project description:Analysis of inguinal white adipose tissue (WAT) and liposarcoma (LPS) isolated from Notch1 overexpression mice (Ad/NICD). Results provide insight into molecular mechanisms underlying tumorigenic transformation of Ad/NICD mature adipocytes
Project description:Obesity is considered as a major public health concern with strong economic and social burdens. Exposure to pollutants such as heavy metals can contribute to the development of obesity and its associated metabolic disorders, including type 2 diabetes and cardiovascular diseases. Adipose tissue is an endocrine and paracrine organ that plays a key role in the development of these diseases and is one of the main target of heavy metal accumulation. In this study, we determined by inductively coupled plasma mass spectrometry cadmium concentrations in human subcutaneous and visceral adipose tissues, ranging between 2.5 nM and 2.5 µM. We found a positive correlation between cadmium levels and age, sex and smoking status and a negative correlation between cadmium and body mass index. Based on cadmium adipose tissue concentrations found in humans, we investigated the effects of cadmium exposure, at concentrations between 1 nM and 10 µM, on adipose-derived human mesenchymal stem cells differentiated into mature adipocytes in vitro. Transcriptomic analysis highlighted that such exposure altered the expression of genes involved in trace element homeostasis and heavy metal detoxification, such as Solute Carrier Family transporters and metallothioneins. This effect correlated with zinc level alteration in cells and cellular media. Interestingly, dysregulation of zinc homeostasis and transporters has been particularly associated with the development of obesity and type 2 diabetes. Moreover, we found that cadmium exposure induces the pro-inflammatory state of the adipocytes by enhancing the expression of genes such as IL-6, IL-1B and CCL2, cytokines also induced in obesity. Finally, cadmium modulates various adipocyte functions such as the insulin response signaling pathway and lipid homeostasis. Collectively, our data identified some of the cellular mechanisms by which cadmium alters adipocyte functions, thus highlighting new facets of its potential contribution to the progression of metabolic disorders.
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.
Project description:To investigate the effects of acute loss of mature adipocytes in adipose tissue on the liver, we created tamoxifen-inducible adipocyte-specific insulin receptor knockout (iFIRKO) mice. We then performed comprehensive gene expression analysis on the liver of iFIRKO and control mice.