Project description:The rising incidence of obesity and related disorders such as diabetes and heart disease has focused considerable attention on the discovery of novel therapeutics. One promising approach has been to increase the number or activity of brown-like adipocytes in white adipose depots, as this has been shown to prevent diet-induced obesity and reduce the incidence and severity of type 2 diabetes. Thus, the conversion of fat-storing cells into metabolically active thermogenic cells has become an appealing therapeutic strategy to combat obesity. Here, we report a screening platform for the identification of small molecules capable of promoting a white-to-brown metabolic conversion in human adipocytes. We identified two inhibitors of Janus Kinase (JAK) activity with no precedent in adipose tissue biology that permanently confer brown-like metabolic activity to white adipocytes. Importantly, these metabolically converted adipocytes exhibit elevated UCP1 expression and increased mitochondrial activity. We further found that repression of interferon signalling and activation of hedgehog signalling in JAK-inactivated adipocytes contributes to the metabolic conversion observed in these cells. Our findings highlight a novel role for the JAK/STAT pathway in the control of adipocyte function and establish a platform to identify compounds for the treatment of obesity. Human pluripotent stem-cell derived mesenchymal progenitor cells (PSC-MPCs), white adipose cells (PSC-WA), and brown adipose cells (PSC-BA) were treated with DMSO (as control), a JAK3-inhibitor compound, and a SYK-inhibitor compound respectively. Transcriptomic expression profiling was performed at 24 hours and 7 days respectively. Three biological replicates are available for each condition defined by cell type, compound, and time.
Project description:The rising incidence of obesity and related disorders such as diabetes and heart disease has focused considerable attention on the discovery of novel therapeutics. One promising approach has been to increase the number or activity of brown-like adipocytes in white adipose depots, as this has been shown to prevent diet-induced obesity and reduce the incidence and severity of type 2 diabetes. Thus, the conversion of fat-storing cells into metabolically active thermogenic cells has become an appealing therapeutic strategy to combat obesity. Here, we report a screening platform for the identification of small molecules capable of promoting a white-to-brown metabolic conversion in human adipocytes. We identified two inhibitors of Janus Kinase (JAK) activity with no precedent in adipose tissue biology that permanently confer brown-like metabolic activity to white adipocytes. Importantly, these metabolically converted adipocytes exhibit elevated UCP1 expression and increased mitochondrial activity. We further found that repression of interferon signalling and activation of hedgehog signalling in JAK-inactivated adipocytes contributes to the metabolic conversion observed in these cells. Our findings highlight a novel role for the JAK/STAT pathway in the control of adipocyte function and establish a platform to identify compounds for the treatment of obesity.
Project description:Ramirez2017 - Human global metabolism in
brown and white adipocytes
Recon 2.1A, an update to Recon 2.1x, is suitable for
quantitatively-realistic results for flux balance analysis in
human metabolism.
This model is described in the article:
Integrating Extracellular
Flux Measurements and Genome-Scale Modeling Reveals Differences
between Brown and White Adipocytes.
Ramirez AK, Lynes MD, Shamsi F, Xue
R, Tseng YH, Kahn CR, Kasif S, Dreyfuss JM.
Cell Rep 2017 Dec; 21(11):
3040-3048
Abstract:
White adipocytes are specialized for energy storage, whereas
brown adipocytes are specialized for energy expenditure.
Explicating this difference can help identify therapeutic
targets for obesity. A common tool to assess metabolic
differences between such cells is the Seahorse Extracellular
Flux (XF) Analyzer, which measures oxygen consumption and media
acidification in the presence of different substrates and
perturbagens. Here, we integrate the Analyzer's metabolic
profile from human white and brown adipocytes with a
genome-scale metabolic model to predict flux differences across
the metabolic map. Predictions matched experimental data for
the metabolite 4-aminobutyrate, the protein ABAT, and the
fluxes for glucose, glutamine, and palmitate. We also uncovered
a difference in how adipocytes dispose of nitrogenous waste,
with brown adipocytes secreting less ammonia and more urea than
white adipocytes. Thus, the method and software we developed
allow for broader metabolic phenotyping and provide a distinct
approach to uncovering metabolic differences.
This model is hosted on
BioModels Database
and identified by:
MODEL1703310000.
To cite BioModels Database, please use:
Chelliah V et al. BioModels: ten-year
anniversary. Nucl. Acids Res. 2015, 43(Database
issue):D542-8.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
CC0
Public Domain Dedication for more information.
Project description:Secreted proteins from adipose tissue play a role in metabolic cross-talk and homeostasis. We performed high sensitivity mass spectrometry-based proteomics on the cell media of human adipocytes derived from the supraclavicular brown adipose and from the subcutaneous white adipose depots of adult humans. We identified 471 potentially secreted proteins covering interesting protein categories such as hormones, growth factors, extracellular matrix proteins and proteins of the complement system, which were differentially regulated in brown and white adipocytes. A total of 101 proteins were exclusively quantified in brown adipocytes and among these were ependymin-related protein 1 (EPDR1). Functional studies suggested a role for EPDR1 in thermogenic adipogenesis. In conclusion, we report substantial differences between the secretomes of brown and white human adipocytes and identify novel candidate batokines that can be important regulators of metabolism.
Project description:Brown adipose tissue (BAT) is a central thermogenic organ that enhances energy expenditure (EE) and cardiometabolic health. However, regulators that specifically increase the number of thermogenic adipocytes are still an unmet need. Here, we show by phosphoproteomics that cAMP activates distinct signaling pathways in brown progenitors, with the cAMP-EPAC1 axis enhancing proliferation and differentiation of thermogenic but not white adipocytes. Further analysis revealed that a specific subpopulation of preadipocytes that are PDGFRα-positive express EPAC1. In vivo, pharmacological activation of EPAC1 enhances BAT growth and browning of white fat, leading to increased EE and reduced diet-induced adiposity. In contrast, mice lacking EPAC1 in PDGFRα-positive preadipocytes show the opposite phenotype. Importantly, EPAC1 activation enhances proliferation and differentiation of human brown adipocytes and human brown fat organoids. Interestingly, a coding variant in EPAC1 that positively correlates with BMI abolishes norepinephrine-induced proliferation of brown adipocytes. Thus, EPAC1 might be an attractive target to enhance thermogenic adipocyte number and EE to combat metabolic diseases.
Project description:This study aimed at determining the transcriptional changes associated with the white-to-brown conversion of human mesenchymal adipose-derived stem cells firstly differentiated into white adipocytes (in the presence of rosiglitazone from day 2 to day 9). White differentiation was completed within 14 days, and PPARg (rosiglitazone) or PPARa (GW7647) agonists were added to the medium for 4 additional days to induce the brown phenotype. Cells were harvested at day 18 and processed for microarray experiments (Agilent).
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:We report molecular characterization of human brown and white adipocytes. We showed that PAZ6 and SW872 cells exhibit classical molecular and phenotypic markers of brown and white adipocytes, respectively. However, SGBS cells presented a versatile phenotype of adipocyte