Project description:Brown adipose tissue (BAT) evolved in mammals as a natural defence system against hypothermia and obesity. While existence of BAT in adult humans has been recently appreciated, its cellular origin and molecular identity remain elusive due in large to high cellular heterogeneity within adipose tissues. Here we isolated clonal adipocytes from adult human BAT as well as WAT (control) and critically analyzed their transcriptome to identify bona fide BAT markers and its new functions.
Project description:Brown fat generates heat via the mitochondrial uncoupling protein UCP1, defending against hypothermia and obesity. Recent data suggest that there are two distinct types of brown fat: classical brown fat derived from a myf-5 cellular lineage and UCP1-positive cells that emerge in white fat from a non-myf-5 lineage. Here, we report the isolation of “beige” cells from murine white fat depots. Microarray analysis of the differentiated clonal inguinal and interscapular adipocytes in the presence of forskolin (10mM). These samples were profiled using Affymetrix mouse 430 2.0 arrays, 26 samples in total.
Project description:Blnc1 is a novel nuclear lncRNA that promotes brown and beige adipocyte differentiation and function. Blnc1 forms a ribonucleoprotein complex with transcription factor EBF2 to stimulate the thermogenic gene program. Further, Blnc1 itself is a target of EBF2, thereby forming a feedforward regulatory loop to drive adipogenesis toward thermogenic phenotype. We used microarrays to elucidate the role of Blnc1 on brown adipocyte differentiation and the induction of the thermogenic gene program. Brown adipocytes expressing vector or brown fat lncRNA 1 (blnc1) were differentiated for 6 days and harvested for RNA isolation and microarray using Affymetrix Mouse MG-430 PM Strip arrays. Two replicated samples were included in this study.
Project description:The adipose organ, including white and brown adipose tissues, is an important player in systemic energy homeostasis, storing excess energy in form of lipids while releasing energy upon various energy demands. Recent studies have demonstrated that white and brown adipocytes also function as endocrine cells and regulate systemic metabolism by secreting factors that act locally and systemically. However, a comparative proteomic analysis of secreted factors from white and brown adipocytes and their responsiveness to adrenergic stimulation has not been reported yet. Therefore, we studied and compared the secretome of white and brown adipocytes, with and without norepinephrine (NE) stimulation. Our results reveal that in the absence of NE, carbohydrate metabolism-regulating proteins are preferably secreted from white adipocytes, while brown adipocytes predominantly secrete integrin signaling proteins. Upon NE stimulation, white adipocytes secrete more proteins involved in lipid metabolism, while brown adipocytes secrete more proteins with specific anti-inflammatory properties. In conclusion, our study provides a comprehensive catalogue of novel adipokine candidates secreted from white and brown adipocytes with many of them responsive to NE.
Project description:Brown adipose tissue (BAT) holds therapeutic potential for obesity and metabolic syndrome via increasing energy expenditure. Both inter- and intra-individual differences contribute to heterogeneity in human BAT and potentially to differential thermogenic capacity in human populations. Here, we demonstrated the generation of brown and white preadipocyte clones from human neck fat and characterized their adipogenic differentiation and thermogenic function. Combining a UCP1 reporter system and gene expression profiling, we defined novel sets of gene signatures in human preadipocytes that could predict the thermogenic potential of mature adipocytes. Knocking out the positive UCP1 regulators, PREX1 and EDNRB, in brown preadipocytes by CRISPRs markedly abolished the high level of UCP1 in mature brown adipocytes. Finally, we showed the ability to prospectively isolate adipose progenitors with great thermogenic potential. These data provide new insights into the cellular heterogeneity in human fat and offer clinically relevant gene targets that mark thermogenically competent preadipocytes. Highly adipogenic clonal white and brown cell lines
Project description:We have identified a population of adipocytes in fat tissue that arise from bone marrow-derived progenitor cells. We used microarrays to compare the global gene expression patterns of the bone marrow progenitor-derived adipocytes as well as conventional white and brown adipocytes to evaluate the relationship between these adipocyte subpopulations. Gonadal fat tissue (for white adipocytes) and intrascapular fat tissue (for brown adipocytes) was digested with collagenase and adipocytes were recovered by centrifugation/flotation. Bone marrow derived adipocytes were isolated from the adipocyte fraction of gonadal fat tissue from mice receiving bone marrow tranplants from donors expressing either green fluorescent protein (GFP) or beta-galactosidase (LacZ) by flow cytometry.
Project description:Brown adipose tissue (BAT) dissipates energy and promotes cardio-metabolic health4. However, loss of BAT during obesity and aging is a principal hurdle for BAT-centered obesity therapies. So far not much is known about BAT apoptosis and signals released by apoptotic brown adipocytes. Here, untargeted metabolomics demonstrated that apoptotic brown adipocytes release a specific pattern of metabolites with purine metabolites being highly enriched. Interestingly, this apoptotic secretome enhances expression of the thermogenic program in healthy adipocytes to maintain tissue functionality. This effect is mediated by the purine inosine which stimulates energy expenditure (EE) in brown adipocytes. Phosphoproteomic analysis demonstrated activation of the cAMP/protein kinase A signaling pathway and of pro-thermogenic transcription factors by inosine.
Project description:We have identified a population of adipocytes in fat tissue that arise from bone marrow-derived progenitor cells. We used microarrays to compare the global gene expression patterns of the bone marrow progenitor-derived adipocytes as well as conventional white and brown adipocytes to evaluate the relationship between these adipocyte subpopulations.
Project description:Cre recombinase activity was induced in differentiating brown adipocytes from CreERT2 Sykflox/flox mice in vitro, which resulted in a partial loss of Syk protein in mature brown adipocytes. Such cells were viable, morphologically normal and displayed largely normal gene expression as indicated by mRNA sequencing and qPCR analysis, suggesting that Syk is not required for survival and gene expression of terminally differentiated brown adipocytes. mRNA sequencing of Syk depleted brown adipocytes treated with 0.1 microM isoproterenol for 6 h showed that 2460 genes were not induced or suppressed upon stimulation. Gene set enrichment analysis revealed a great enrichment for genes essential for mitochondrial respiration and biogenesis, for genes associated with and required for adipogenesis, as well as for genes responsive to various stimuli in adipocytes among genes highly ranked by reduced fold changes in response to isoproterenol in the Syk deficient brown adipocytes.