Reduced lipolysis is a common lipid accumulation mechanism for different subtypes of lipomas
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE141027 | GEO | 2020/05/25
REPOSITORIES: GEO
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Project description:Reduced lipolysis is a common lipid accumulation mechanism for different subtypes of lipomas
| PRJNA591799 | ENA
Project description:Noncanonical lipolysis induced by inflammatory cytokines or toll-like receptor ligands is required for the regulation of inflammation during endotoxemia and sepsis. Canonical lipolysis induced by catecholamines declines during aging, but the extent to which the noncanonical pathway of lipolysis is active during aging remains unknown. The immune compartment of visceral white adipose tissue (vWAT) changes during aging, including an expansion of lymphocytes, pro-inflammatory macrophage polarization, and an increase in chronic low-grade inflammation, all of which influence canonical lipolysis in old vWAT. Therefore, we aimed to define the extent to which immune cells from older hosts influence noncanonical lipolysis induced by sepsis. Here we show that models of polymicrobial sepsis and lipopolysaccharide (LPS)-induced endotoxemia induce vWAT lipolysis in young mice but fail to activate lipolytic pathways in vWAT from old mice. Characterization of vWAT B cells revealed an accumulation of dysfunctional B1 B cells and an amplified inflammatory signature induced by LPS in old B1 B cells compared to old B2 B cells. Short term depletion of B2 B cells from old mice and adoptive transfer of peritoneal B cells from old mice into young recipient mice were insufficient to alter LPS-stimulated lipolysis. However, life-long deficiency of B cells increased LPS-stimulated lipolysis, suggesting the suppressive role of B cells may be indirect and requires other cell types. Pro-inflammatory macrophages and NLRP3 inflammasome activation were significantly reduced in the old B cell knockout mice. These data collectively reveal a decline in noncanonical lipolysis in vWAT during aging that is regulated by resident immune cells. Additionally, our study suggests the B cell-macrophage signaling axis may offer new approaches to resolve metabolic dysfunction in aged vWAT and attenuate septic severity in older individuals.
2024-03-18 | GSE250371 | GEO
Project description:BackgroundElucidation of lipid metabolism and accumulation mechanisms is of paramount importance to understanding obesity and unveiling therapeutic targets. In vitro cell models have been extensively used for these purposes, yet, they do not entirely reflect the in vivo setup. Conventional lipomas, characterized by the presence of mature adipocytes and increased adipogenesis, could overcome the drawbacks of cell cultures. Also, they have the unique advantage of easily accessible matched controls in the form of subcutaneous adipose tissue (SAT) from the same individual. We aimed to determine whether lipomas are a good model to understand lipid accumulation.MethodsWe histologically compared lipomas and control SAT, followed by assessment of the lipidome using high-resolution 1H NMR spectroscopy and ESI-IT mass spectrometry. RNA-sequencing was used to obtain the transcriptome of lipomas and the matched SAT.ResultsWe found a significant increase of small-size (maximal axis?<?70?µm) and very big (maximal axis?>?150?µm) adipocytes within lipomas. This suggests both enhanced adipocyte proliferation and increased lipid accumulation. We further show that there is no significant change in the lipid composition compared to matched SAT. To better delineate the pathophysiology of lipid accumulation, we considered two groups with different genetic backgrounds: (1) lipomas with HMGA2 fusions and (2) without gene fusions. To reduce the search space for genes that are relevant for lipid pathophysiology, we focused on the overlapping differentially expressed (DE) genes between the two groups. Gene Ontology analysis revealed that DE genes are enriched in pathways related to lipid accumulation.ConclusionsWe show that the common shared lipid accumulation mechanism in lipoma is a reduction in lipolysis, with most gene dysregulations leading to a reduced cAMP in the adipocyte. Superficial lipomas could thus be used as a model for lipid accumulation through altered lipolysis as found in obese patients.
| S-EPMC7906903 | biostudies-literature
Project description:β-Adrenergic signaling is a core regulator of brown adipocyte function stimulating both lipolysis and transcription of thermogenic genes, thereby expanding the capacity for oxidative metabolism. Here we have used pharmacological inhibitors and a novel direct activator of lipolysis to acutely modulate the activity of lipases, thereby enabling us to uncover lipolysis-dependent signaling pathways downstream of β-adrenergic signaling in brown adipocytes. We show that induction of lipolysis leads to acute induction of several gene programs and is required for transcriptional regulation by β-adrenergic signals. Using machine-learning algorithms to infer causal transcription factors, we show that PPARs are key mediators of lipolysis-induced activation of genes involved in lipid metabolism and thermogenesis. Importantly, lipolysis also activates the unfolded protein response and regulates the core circadian transcriptional machinery independently of PPARs. Our results demonstrate that lipolysis generates important metabolic signals that exert profound pleiotropic effects on brown adipocyte transcription and function.
2022-05-15 | GSE202833 | GEO
Project description:Lipolysis is an early event during derma; fibrosis progression. We wanted to see how the loss of lipolysis impacted cell dynamics within the
2024-06-01 | GSE256411 | GEO
Project description:β-Adrenergic signaling is a core regulator of brown adipocyte function stimulating both lipolysis and transcription of thermogenic genes, thereby expanding the capacity for oxidative metabolism. Here we have used pharmacological inhibitors and a novel direct activator of lipolysis to acutely modulate the activity of lipases, thereby enabling us to uncover lipolysis-dependent signaling pathways downstream of β-adrenergic signaling in brown adipocytes. We show that induction of lipolysis leads to acute induction of several gene programs and is required for transcriptional regulation by β-adrenergic signals. Using machine-learning algorithms to infer causal transcription factors, we show that PPARs are key mediators of lipolysis-induced activation of genes involved in lipid metabolism and thermogenesis. Importantly, lipolysis also activates the unfolded protein response and regulates the core circadian transcriptional machinery independently of PPARs. Our results demonstrate that lipolysis generates important metabolic signals that exert profound pleiotropic effects on brown adipocyte transcription and function.
2022-05-21 | GSE203247 | GEO
Project description:β-Adrenergic signaling is a core regulator of brown adipocyte function stimulating both lipolysis and transcription of thermogenic genes, thereby expanding the capacity for oxidative metabolism. Here we have used pharmacological inhibitors and a novel direct activator of lipolysis to acutely modulate the activity of lipases, thereby enabling us to uncover lipolysis-dependent signaling pathways downstream of β-adrenergic signaling in brown adipocytes. We show that induction of lipolysis leads to acute induction of several gene programs and is required for transcriptional regulation by β-adrenergic signals. Using machine-learning algorithms to infer causal transcription factors, we show that PPARs are key mediators of lipolysis-induced activation of genes involved in lipid metabolism and thermogenesis. Importantly, lipolysis also activates the unfolded protein response and regulates the core circadian transcriptional machinery independently of PPARs. Our results demonstrate that lipolysis generates important metabolic signals that exert profound pleiotropic effects on brown adipocyte transcription and function.
2022-05-15 | GSE202834 | GEO
Project description:β-Adrenergic signaling is a core regulator of brown adipocyte function stimulating both lipolysis and transcription of thermogenic genes, thereby expanding the capacity for oxidative metabolism. Here we have used pharmacological inhibitors and a novel direct activator of lipolysis to acutely modulate the activity of lipases, thereby enabling us to uncover lipolysis-dependent signaling pathways downstream of β-adrenergic signaling in brown adipocytes. We show that induction of lipolysis leads to acute induction of several gene programs and is required for transcriptional regulation by β-adrenergic signals. Using machine-learning algorithms to infer causal transcription factors, we show that PPARs are key mediators of lipolysis-induced activation of genes involved in lipid metabolism and thermogenesis. Importantly, lipolysis also activates the unfolded protein response and regulates the core circadian transcriptional machinery independently of PPARs. Our results demonstrate that lipolysis generates important metabolic signals that exert profound pleiotropic effects on brown adipocyte transcription and function.
2022-06-03 | GSE205127 | GEO
Project description:As cows progress from pregnancy to lactation, the adipose tissues (AT) undergo adaptations characterized by the mobilization of free fatty acids (FFA) through lipolysis to address energy deficiencies. Typically, in clinically healthy cows, the intensity of lipolysis decreases during lactation. However, when the release of FFA surpasses tissue requirements, it leads to the accumulation of lipid-derived products, heightening the susceptibility of cows to metabolic and infectious diseases. A second factor correlated to disease incidence in dairy cows is the presence of bacterial endotoxins in blood. The last is implicated in AT lipolysis and dysfunction in mammals. However, the mechanisms by which endotoxin activates lipolysis and affects the formation of lipid derived products in bovine adipocyte remains unknown. We hypothesize that endotoxin triggers AT dysfunction by increasing the synthesis and release of lipid-derived products with proinflammatory potential. Preadipocytes were obtained from subcutaneous AT of multiparous Holstein cows (n=9). Adipogenesis was induced for 7 d and cells were incubated with endotoxin [lipopolysaccharide 1µg/mL (LPS)] for up to 7 h. Beta-adrenergic receptor agonist isoproterenol (ISO; 1 µM) was used as an activator of canonical lipolysis. The antilipolytic effect of insulin was evaluated alone or in combination with LPS. Lipolysis was evaluated by the release of glycerol in the media. RNA from adipocytes was sequenced in Illumina NextSeqData, and Differential Expressed Genes (DEG) identified. Enrichment and network analyses were performed in Ingenuity Pathways (IPA). Our findings provide evidence supporting the higher abundance of lipid-derived products with proinflammatory activity and dysfunction related to inflammatory activation.
2024-05-20 | GSE267141 | GEO
Project description:β-Adrenergic signaling is a core regulator of brown adipocyte function stimulating both lipolysis and transcription of thermogenic genes, thereby expanding the capacity for oxidative metabolism. Here we have used pharmacological inhibitors and a novel direct activator of lipolysis to acutely modulate the activity of lipases, thereby enabling us to uncover lipolysis-dependent signaling pathways downstream of β-adrenergic signaling in brown adipocytes. We show that induction of lipolysis leads to acute induction of several gene programs and is required for transcriptional regulation by β-adrenergic signals. Using machine-learning algorithms to infer causal transcription factors, we show that PPARs are key mediators of lipolysis-induced activation of genes involved in lipid metabolism and thermogenesis. Importantly, lipolysis also activates the unfolded protein response and regulates the core circadian transcriptional machinery independently of PPARs. Our results demonstrate that lipolysis generates important metabolic signals that exert profound pleiotropic effects on brown adipocyte transcription and function.
2022-06-03 | GSE205174 | GEO