Loss of the armadillo-repeat protein Plakophilin 2 in obesity breaks cell cycle dynamics to breed adipocyte senescence
Ontology highlight
ABSTRACT:
INSTRUMENT(S): timsTOF Pro
ORGANISM(S): Homo Sapiens (ncbitaxon:9606)
SUBMITTER: 
Francisco Ortega
PROVIDER: MSV000091898 | MassIVE | Wed May 10 00:46:00 BST 2023
SECONDARY ACCESSION(S): PXD042110
REPOSITORIES: MassIVE
Similar Datasets
Project description:Olfactomedin-2 (OLFM2) participates in brain development and appears to be involved in energy handling. In adipose tissue, we here show expression of OLFM2 to be adipocyte-specific and opposed to obesity. OLFM2 levels are increased during adipogenesis, and impaired when differentiated fat cells are challenged with conditions emulating inflammation in the context of obesity. On the molecular level, examination of OLFM2 deficiency in human adipocytes indicated down-regulation of genes related to cell cycle. At the cellular level, the loss of OLFM2 compromised adipogenesis, while its over-production enhanced the adipogenic transformation of 3T3-L1 cells. Complementary loss and gain of function assays coupled to untargeted proteomics revealed the modulation of key protein pathways, including regulation of citrate cycle, fatty acid degradation, axon guidance and focal adhesion in mature adipocytes and precursor cells. Transferring these findings into animal models using a whole-body knockout and transcriptionally depleted adipose Olfm2 highlighted, respectively, a cluster of molecular changes connected with defective cell cycle (in both), fat mass accretion and impaired metabolism (in the latter). Our data underscores a key role for OLFM2 in fat cells, and suggests that the association between adipose OLFM2 and obesity is not only correlative but also causative.
2023-11-16 | MSV000093409 | MassIVE
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:Olfactomedin 2 (OLFM2) is a central player in development that also appears to be a critical mediator for energy handling. Here we report that in adipose tissue, expression of OLFM2 is opposite to obesity, being increased upon weight loss. Concurrently, we show steadily increased OLFM2 during adipogenesis, with expression levels reaching its zenith in terminally differentiated adipocytes. Notably, we demonstrate that the loss of this specific olfactomedin domain-containing protein in fat cell progenitors dampens adipogenesis, while the adipogenic conversion is bolstered in engineered 3T3-L1 cells with increased OLFM2. Our seminal findings also bound dwindled expressions of adipocyte-specific OLFM2 to the inflammatory state in the context of obesity, mainly characterized by the influence of macrophage-derived cytokines. Then, we show that the loss of OLFM2 in human adipocytes displays the transient downregulation of genes related to cell cycle, also coupled to deranged energy storage. Next, we transitioned our results to mice models in which whole-body knockout and transcriptionally regulated adipose-specific Olfm2 compel a cluster of molecular changes tightly related to impaired cell cycle (in both) and fat mass accretion (in the later). Current findings unveil the previously unknown expression of OLFM2 in adipocytes and the control of cellular mechanisms related to the obese phenotype exercised by this scaffold protein in adipose tissues.
2023-12-31 | GSE214900 | GEO
Project description:Obesity is a health problem characterized by large expansion of adipose tissue. During this expansion, genotoxic stressors can be accumulated and negatively affect the Mesenchymal Stem Cells (MSCs) of adipose tissue. Due to the oxidative stress generated by these genotoxic stressors, senescence phenotype might be observed in adipose tissue MSCs. Senescent MSCs lose their proliferations and differentiation properties and secrete senescence-associated molecules to their niche thus triggering senescence for the rest of the tissue. Accumulation of senescent cells in adipose tissue results in decreased tissue regeneration and functional impairment not only in the close vicinity but also in the other tissues. Here we hypothesized that declined tissue regeneration might be associated with loss of stemness in MSCs population. We analyzed the expression of several stemness genes in adipose tissue MSCs of high-fat diet and normal diet mice models. Since the MSCs population covers a small percentage of the pluripotent stem cells, a role in proliferation and tissue regeneration, we measured the percentage of these cells via TRA-1-60 surface antigen. Additionally, by conducting a shotgun proteomic approach using LC-MS/MS, whole cell proteome of the adipose tissue MSCs of high-fat diet and normal diet mice were analyzed and identified proteins were evaluated via Gene Ontology and PPI network analysis. MSCs of obese mice showed senescent phenotype and altered cell cycle distribution due to a hostile environment with oxidative stress in adipose tissue where they reside. Additionally, the number of pluripotent markers expressing cells declined in the MSC population of the high-fat diet mice. Gene expression analysis evidenced the loss of stemness with a decrease in the expression of stemness-associated genes. Of the proteomic comparison of the normal and the high-fat diet group, MSCs revealed that stemness-associated molecules were decreased while inflammation and senescence-associated phenotypes emerged in obese mice MSCs. Our results showed us that the MSCs of adipose tissue may lose their stemness properties due to obesity-associated stress conditions.
2024-10-17 | PXD050811 | Pride
Project description:Brown adipose tissue (BAT) dissipates chemical energy in the form of heat, as a defense against hypothermia and obesity. Current evidence indicates that brown adipocytes arise from Myf5+-dermotomal precursors through the action of a PRDM16-C/EBP-_ transcriptional complex; however, the underlying mechanisms that determine lineage specification and maintenance of brown adipose cells remain poorly understood. Here we study the role of euchromatic histone-lysine N-methyltransferase 1 (EHMT1), a brown fat-enriched lysine methyltransferase, as an essential enzymatic component of the PRDM16 transcriptional complex and controls brown adipose cell fate. To identify targets and function of EHMT1, we performed genome-wide gene expression profiling of BAT from control mouce (Ehmt1flox/flox), Ehmt1Myf5 KO mouse (Myf5-Cre+/-; Ehmt1flox/flox) and Ehmt1adipo KO mouse (Adipo-Cre+/-; Ehmt1flox/flox). Loss of EHMT1 in Myf5+ lineage causes a near total loss of brown fat characteristics and induces muscle-selective gene program in vivo. In addition, adipose-specific deletion of EHMT1 by Adipo-Cre leads to a marked reduction of the thermogenic and fat oxidation genes.
2013-11-07 | E-MTAB-1704 | biostudies-arrayexpress
Project description:Background. Obesity and body fat distribution are important risk factors for the development of type 2 diabetes and metabolic syndrome. Evidence has accumulated that this risk is related to intrinsic differences in behavior of adipocytes in different fat depots. LIM Domain Only 3 (LMO3) plays a crucial role in adipogenesis modulating the key adipogenic master switch PPARγ in human, but not mouse, visceral adipose progenitors; however, despite high expression in mature adipocytes, its function in these cells is currently unknown. Aims/Hypothesis. The aim of this study was to determine the potential involvement of LMO3-dependent pathways in the modulation of key functions of mature adipocytes during obesity. Methods. Based on a recently engineered hybrid rAAV serotype Rec2 shown to efficiently transduce both brown adipose tissue (BAT) and white adipose tissue (WAT), we delivered YFP or Lmo3 to epididymal WAT (eWAT) of C57Bl6/J mice on a high fat diet (HFD). The effects of eWAT transduction on metabolic parameters were evaluated 10 weeks later. To further define the role of LMO3 in insulin-stimulated glucose uptake, insulin signaling, adipocyte bioenergetics as well as endocrine function, experiments were conducted in 3T3-L1 adipocytes and newly differentiated human primary mature adipocytes, engineered for transient gain- or loss of LMO3 expression, respectively.Results. AAV transduction of eWAT results in strong and stable Lmo3 expression specifically in the adipocyte fraction over a course of 10 weeks with HFD feeding. Lmo3 expression in eWAT significantly improved glucose clearance and insulin sensitivity in diet-induced obesity, paralleled by increased serum adiponectin. In vitro, Lmo3 expression in 3T3-L1 adipocytes increased insulin-stimulated GLUT4 translocation and glucose uptake as well as mitochondrial oxidative capacity in addition to fatty acid oxidation. On a molecular level, LMO3 augmented PPARg activity, oxidative mitochondrial gene expression, which depended on and the expression of the PPARg co-activator Ncoa1, which was required for LMO3 effects on mitochondria and glucose uptake. In human mature adipocytes, LMO3 overexpression promoted, while silencing of LMO3 suppressed mitochondrial oxidative capacity. Conclusions. LMO3 expression in visceral adipose tissue regulates multiple genes that preserve adipose tissue functionality during obesity, such as glucose tolerance, insulin sensitivity and adiponectin secretion. Together with increased PPARγ activity, these gene expression changes promote insulin-induced GLUT4 translocation, glucose uptake in addition to increased mitochondrial oxidative capacity, limiting HFD-induced adipose dysfunction. These data add LMO3 as a novel regulator improving visceral adipose tissue function during obesity.
2021-08-24 | GSE155781 | GEO
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.
2014-10-31 | E-GEOD-57896 | biostudies-arrayexpress
Project description:Toll-like receptors/Interleukin-1 receptor (IL-1R) signaling plays an important role in High-fat diet (HFD)-induced adipose tissue dysfunction contributing to obesity-associated metabolic syndromes. Here, we show an unconventional IL-1R-IRAKM (IL-1R-associated kinase M)-Slc25a1 signaling axis in adipocytes that reprograms lipogenesis to promote diet-induced obesity. Adipocyte-specific deficiency of IRAKM reduced HFD-induced body weight gain, increased whole body energy expenditure and improved insulin resistance, associated with decreased lipid accumulation and adipocyte cell sizes. IL-1β stimulation induced the translocation of IRAKM Myddosome to mitochondria to promote de novo lipogenesis in adipocytes. Mechanistically, IRAKM interacts with and phosphorylates mitochondrial citrate carrier Slc25a1 to promote IL-1β-induced mitochondrial citrate transport to cytosol and de novo lipogenesis. Moreover, IRAKM-Slc25a1 axis mediates IL-1β induced Pgc1a acetylation to regulate thermogenic gene expression in adipocytes. IRAKM kinase-inactivation also attenuated HFD-induced obesity. Taken together, our study suggests that the IL-1R-IRAKM-Slc25a1 signaling axis tightly links inflammation and adipocyte metabolism, indicating a novel therapeutic target for obesity.
2022-06-09 | PXD031934 | Pride
Project description:The chronic inflammatory state that accompanies obesity is a major contributor to insulin resistance and other metabolic dysfunction features. Despite recent advances in our understanding of the cellular and secreted factors that promote the inflammatory milieu of obesity, we have much less insight into the transcriptional pathways that drive these processes. While most attention has focused on the canonical inflammatory transcription factor NF-KB, other potentially important factors exist, including members of the interferon regultory factor (IRF) family. Here we show that IRF3 expression is upregulated in the adipocytes of obese mice and humans. TLR3/TLR4 activation induces insulin resistance in adipocytes, which can be prevented by IRF3 knockdown. Furthermore, Irf3KO mice display improved insulin sensitivity, associated with reduced intra-adipose and systemic inflammation in the high-fat fed state, enhanced browning of subcutaneous fat, and increased adipose expression of Glut4. Taken together, our data indicates that IRF3 is a major transcriptional regulator of adipose inflammation to maintain systemic glucose and energy homeostasis. Transcriptional profiling of murine 3T3-L1 adipocytes with altered expression of IRF3. Overexpression or knockdown of IRF3 was achieved by lentivirus transduction for 6 days. 3T3-L1 adipocytes with IRF3 knockdown were further treated in the absence or presence of LPS for 6 days. Samples consist of triplicate replica with appropriate control.
2016-05-31 | E-GEOD-81193 | biostudies-arrayexpress
Project description:Obesity-associated insulin resistance is characterized by a state of chronic, low-grade inflammation that is associated with the accumulation of M1 proinflammatory macrophages in adipose tissue. Although different evidence explains the mechanisms linking the expansion of adipose tissue and adipose tissue macrophage (ATM) polarization, in the current study we investigated the concept of lipid-induced toxicity as the pathogenic link that could explain the trigger of this response. We addressed this question using isolated ATMs and adipocytes from genetic and diet-induced murine models of obesity. Through transcriptomic and lipidomic analysis, we created a model integrating transcript and lipid species networks simultaneously occurring in adipocytes and ATMs and their reversibility by thiazolidinedione treatment. We show that polarization of ATMs is associated with lipid accumulation and the consequent formation of foam cell–like cells in adipose tissue. Our study reveals that early stages of adipose tissue expansion are characterized by M2-polarized ATMs and that progressive lipid accumulation within ATMs heralds the M1 polarization, a macrophage phenotype associated with severe obesity and insulin resistance. Furthermore, rosiglitazone treatment, which promotes redistribution of lipids toward adipocytes and extends the M2 ATM polarization state, prevents the lipid alterations associated with M1 ATM polarization. Our data indicate that the M1 ATM polarization in obesity might be a macrophage-specific manifestation of a more general lipotoxic pathogenic mechanism. This indicates that strategies to optimize fat deposition and repartitioning toward adipocytes might improve insulin sensitivity by preventing ATM lipotoxicity and M1 polarization. 15 samples; 2 genotypes and 2 time points
2012-03-22 | E-GEOD-36669 | biostudies-arrayexpress