BACKGROUND: Obesity is a major health burden. Preadipocytes proliferate and differentiate in mature adipocytes in the adipogenic process, which could be a potential therapeutic approach for obesity. Deficiency of SIRT6, a stress-responsive protein deacetylase and mono-ADP ribosyltransferase enzyme, blocks adipogenesis. Mutants of SIRT6 (N308K/A313S) were recently linked to the in the long lifespan Ashkenazi Jews. In this study, we aimed to clarify how these new centenarian-associated SIRT6 genetic variants affect adipogenesis at the transcriptional and epigenetic level. METHODS: We analyzed the role of SIRT6 wild-type (WT) or SIRT6 centenarian-associated mutant (N308K/A313S) overexpression in adipogenesis, by creating stably transduced preadipocyte cell lines using lentivirus on the 3T3-L1 model. Histone post-translational modifications (PTM: acetylation, methylation) and transcriptomic changes were analyzed by mass spectrometry (LC-MS/MS) and RNA-Seq, respectively, in 3T3-L1 adipocytes. In addition, the adipogenic process and related signaling pathways were investigated by bioinformatics and biochemical approaches. RESULTS: Overexpression of centenarian-associated SIRT6 mutant increased adipogenic differentiation to a similar extent compared to the WT form. However, it triggered distinct histone PTM profiles in mature adipocytes, with significantly higher acetylation levels, and activated divergent transcriptional programs, including those dependent on signaling related to the sympathetic innervation and to PI3K pathway. 3T3-L1 mature adipocytes overexpressing SIRT6 N308K/A313S displayed increased insulin sensitivity in a neuropeptide Y (NPY)-dependent manner. CONCLUSIONS: SIRT6 N308K/A313S overexpression in mature adipocytes ameliorated glucose sensitivity and impacted sympathetic innervation signaling. These findings highlight the importance of targeting SIRT6 enzymatic activities to regulate the co-morbidities associated with obesity.
- MeSH
- adipogeneze * genetika MeSH
- buňky 3T3-L1 * MeSH
- epigeneze genetická * genetika MeSH
- histony metabolismus genetika MeSH
- lidé MeSH
- mutace MeSH
- myši MeSH
- obezita genetika metabolismus MeSH
- posttranslační úpravy proteinů genetika MeSH
- sirtuiny * genetika metabolismus MeSH
- tukové buňky * metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
To date, single-cell studies of human white adipose tissue (WAT) have been based on small cohort sizes and no cellular consensus nomenclature exists. Herein, we performed a comprehensive meta-analysis of publicly available and newly generated single-cell, single-nucleus, and spatial transcriptomic results from human subcutaneous, omental, and perivascular WAT. Our high-resolution map is built on data from ten studies and allowed us to robustly identify >60 subpopulations of adipocytes, fibroblast and adipogenic progenitors, vascular, and immune cells. Using these results, we deconvolved spatial and bulk transcriptomic data from nine additional cohorts to provide spatial and clinical dimensions to the map. This identified cell-cell interactions as well as relationships between specific cell subtypes and insulin resistance, dyslipidemia, adipocyte volume, and lipolysis upon long-term weight changes. Altogether, our meta-map provides a rich resource defining the cellular and microarchitectural landscape of human WAT and describes the associations between specific cell types and metabolic states.
Glutathione peroxidase 7 (GPx7) acts as an intracellular stress sensor/transmitter and plays an important role in adipocyte differentiation and the prevention of obesity related pathologies. For this reason, finding the regulatory mechanisms that control GPx7 expression is of great importance. As microRNAs (miRNAs) could participate in the regulation of GPx7 expression, we studied the inhibition of GPx7 expression by four selected miRNAs with relation to obesity and adipogenesis. The effect of the transfection of selected miRNAs mimics on GPx7 expression was tested in three cell models (HEK293, SW480, AT-MSC). The interaction of selected miRNAs with the 3'UTR of GPx7 was followed up on using a luciferase gene reporter assay. In addition, the levels of GPx7 and selected miRNAs in adipose tissue mesenchymal stem cells (AT-MSC) and mature adipocytes from four human donors were compared, with the changes in these levels during adipogenesis analyzed. Our results show for the first time that miR-137 and miR-29b bind to the 3'UTR region of GPx7 and inhibit the expression of this enzyme at the mRNA and protein level in all the human cells tested. However, no negative correlation between miR-137 nor miR-29b level and GPx7 was observed during adipogenesis. Despite the confirmed inhibition of GPx7 expression by miR-137 and miR-29b, the action of these two molecules in adipogenesis and mature adipocytes must be accompanied by other regulators.
- MeSH
- 3' nepřekládaná oblast MeSH
- adipogeneze genetika MeSH
- kmenové buňky metabolismus MeSH
- kultivované buňky MeSH
- lidé středního věku MeSH
- lidé MeSH
- messenger RNA metabolismus MeSH
- mikro RNA metabolismus MeSH
- nádorové buněčné linie MeSH
- peroxidasy genetika MeSH
- regulace genové exprese enzymů * MeSH
- tukové buňky metabolismus MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Follistatin-like 1 (FSTL1) is a secreted adipomyokine with a possible link to obesity; however, its connection to extreme obesity currently remains unknown. In order to analyze such association for the very first time, we employed a unique cohort of morbidly and super obese individuals with a mean BMI of 44.77 kg/m2 and measured the levels of circulating FSTL1. We explored the 3' UTR of FSTL1 to locate a genetic variant which impairs microRNA binding. We located and investigated such SNP (rs1057231) in relation to the FSTL1 protein level, obesity status, and other body composition parameters. We observed a significant decline in FSTL1 level in obese subjects in comparison to nonobese ones. The evaluated SNP was found to correlate with FSTL1 only in nonobese subjects. The presented results were not affected by sex since both males and females expressed FSTL1 equally. We suggest that the FSTL1 decrease observed in extremely obese subjects is a result of adipogenesis reduction accompanied by a senescence of preadipocytes which otherwise willingly express FSTL1, increased adipocyte apoptosis, and epigenetic FSTL1 silencing.
- MeSH
- 3' nepřekládaná oblast MeSH
- adipogeneze genetika MeSH
- běloši MeSH
- biologické markery krev MeSH
- dospělí MeSH
- down regulace MeSH
- jednonukleotidový polymorfismus * MeSH
- lidé středního věku MeSH
- lidé MeSH
- mikro RNA metabolismus MeSH
- mladiství MeSH
- morbidní obezita krev genetika MeSH
- obezita krev genetika MeSH
- proteiny související s folistatinem krev genetika MeSH
- senioři MeSH
- vazebná místa MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
Developmental exposure to environmental factors has been linked to obesity risk later in life. Nuclear receptors are molecular sensors that play critical roles during development and, as such, are prime candidates to explain the developmental programming of disease risk by environmental chemicals. We have previously characterized the obesogen tributyltin (TBT), which activates the nuclear receptors peroxisome proliferator-activated receptor γ (PPARγ) and retinoid X receptor (RXR) to increase adiposity in mice exposed in utero. Mesenchymal stem cells (MSCs) from these mice are biased toward the adipose lineage at the expense of the osteoblast lineage, and MSCs exposed to TBT in vitro are shunted toward the adipose fate in a PPARγ-dependent fashion. To address where in the adipogenic cascade TBT acts, we developed an in vitro commitment assay that permitted us to distinguish early commitment to the adipose lineage from subsequent differentiation. TBT and RXR activators (rexinoids) had potent effects in committing MSCs to the adipose lineage, whereas the strong PPARγ activator rosiglitazone was inactive. We show that activation of RXR is sufficient for adipogenic commitment and that rexinoids act through RXR to alter the transcriptome in a manner favoring adipogenic commitment. RXR activation alters expression of enhancer of zeste homolog 2 (EZH2) and modifies genome-wide histone 3 lysine 27 trimethylation (H3K27me3) in promoting adipose commitment and programming subsequent differentiation. These data offer insights into the roles of RXR and EZH2 in MSC lineage specification and shed light on how endocrine-disrupting chemicals such as TBT can reprogram stem cell fate.
- MeSH
- adipogeneze účinky léků genetika fyziologie MeSH
- buněčná diferenciace účinky léků genetika MeSH
- chromatin účinky léků fyziologie MeSH
- endokrinní disruptory farmakologie MeSH
- epigeneze genetická účinky léků MeSH
- exprese genu účinky léků MeSH
- EZH2 protein genetika MeSH
- genový knockdown veterinární MeSH
- mezenchymální kmenové buňky cytologie MeSH
- myši inbrední C57BL MeSH
- myši MeSH
- obezita etiologie MeSH
- PPAR gama fyziologie MeSH
- retinoidní X receptory účinky léků fyziologie MeSH
- sekvenční analýza RNA veterinární MeSH
- trialkylcínové sloučeniny farmakologie MeSH
- tukové buňky cytologie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
In-vitro investigation of the effects of hypoxia is limited by physical laws of gas diffusion and cellular O2 consumption, making prolonged exposures to stable O2 concentrations impossible. Using a gas-permeable cultureware, chronic effects of mild and severe hypoxia on triglyceride accumulation, lipid droplet size distribution, spontaneous lipolysis and gene expression of adipocyte-specific markers were assessed. 3T3-L1 cells were differentiated under 20%, 4% or 1% O2 using a gas-permeable cultureware. Triglyceride accumulation, expression of genes characteristic for advanced adipocyte differentiation and involvement of key lipogenesis enzymes were assessed after exposures. Lipogenesis increased by 375% under mild hypoxia, but dropped by 43% in severe hypoxia. Mild, but not severe, hypoxia increased formation of large lipid droplets 6.4 fold and strongly induced gene expression of adipocyte-specific markers. Spontaneous lipolysis increased by 488% in mild, but only by 135% in severe hypoxia. Inhibition of ATP-dependent citrate lyase suppressed hypoxia-induced lipogenesis by 81% and 85%. Activation of HIF inhibited lipogenesis by 59%. Mild, but not severe, hypoxia stimulates lipolysis and promotes adipocyte differentiation, probably through excess of acetyl-CoA originating from tricarboxylic acid cycle independently of HIF activation.
- MeSH
- acetylkoenzym A metabolismus MeSH
- adipogeneze účinky léků genetika MeSH
- ATP-citrát-(pro-S)-lyasa genetika metabolismus MeSH
- buněčná diferenciace účinky léků MeSH
- buňky 3T3-L1 MeSH
- citrátový cyklus účinky léků genetika MeSH
- diacylglycerol-O-acyltransferasa genetika metabolismus MeSH
- faktor 1 indukovatelný hypoxií - podjednotka alfa genetika metabolismus MeSH
- hypoxie buňky MeSH
- kyslík farmakologie MeSH
- lipidová tělíska chemie účinky léků MeSH
- lipogeneze účinky léků genetika MeSH
- lipolýza účinky léků genetika MeSH
- myši MeSH
- perilipin 1 genetika metabolismus MeSH
- proteiny vázající mastné kyseliny genetika metabolismus MeSH
- regulace genové exprese účinky léků MeSH
- signální transdukce MeSH
- sterolesterasa genetika metabolismus MeSH
- triglyceridy metabolismus MeSH
- tukové buňky cytologie účinky léků metabolismus MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Autophagy is essential for successful white adipocyte differentiation but the data regarding the timing and relevance of autophagy action during different phases of adipogenesis are limited. We subjected 3T3-L1 preadipocytes to a standard differentiation protocol and inhibited the autophagy within time-limited periods (days 0-2; 2-4; 4-6; 6-8) by asparagine or 3-methyladenine. In the normal course of events, both autophagy flux and the mRNA expression of autophagy related genes (Atg5, Atg12, Atg16, beclin 1) is most intensive at the beginning of differentiation (days 0-4) and then declines. The initiation of differentiation is associated with a 50% reduction of the mitochondrial copy number on day 2 followed by rapid mitochondrial biogenesis. Preadipocytes and differentiated adipocytes differ in the mRNA expression of genes involved in electron transport (Nufsd1, Sdhb, Uqcrc1); ATP synthesis (ATP5b); fatty acid metabolism (CPT1b, Acadl); mitochondrial transporters (Hspa9, Slc25A1) and the TCA cycle (Pcx, Mdh2) as well as citrate synthase activity. Autophagy inhibition during the first two days of differentiation blocked both phenotype changes (lipid accumulation) and the gene expression pattern, while having no or only a marginal effect over any other time period. Similarly, autophagy inhibition between days 0-2 inhibited mitotic clonal expansion as well as mitochondrial network remodeling. In conclusion, we found that autophagy is essential and most active during an initial stage of adipocyte differentiation but it is dispensable during its later stages. We propose that the degradation of preadipocyte cytoplasmic structures, predominantly mitochondria, is an important function of autophagy during this phase and its absence prevents remodeling of the mitochondrial gene expression pattern and mitochondrial network organization.
- MeSH
- adipogeneze účinky léků genetika MeSH
- asparagin farmakologie MeSH
- autofagie účinky léků genetika MeSH
- buněčná diferenciace účinky léků genetika MeSH
- buňky 3T3-L1 MeSH
- mitochondrie účinky léků metabolismus MeSH
- myši MeSH
- tukové buňky cytologie účinky léků MeSH
- vývojová regulace genové exprese účinky léků genetika MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Calorie restriction-induced weight loss is accompanied by profound changes in adipose tissue characteristics. To determine the effect of weight loss on differentiation of preadipocytes and secretory capacity of in vitro differentiated adipocytes, we established cultures of these cells from paired subcutaneous adipose tissue biopsies obtained before and at the end of weight-reducing dietary intervention (DI) in 23 obese women. Based on lipid accumulation and the expression of differentiation markers, in vitro adipogenesis increased after weight loss and it was accompanied by enhanced expression of genes involved in de novo lipogenesis. This effect of weight loss was not driven by changes of peroxisome proliferator-activated receptor γ sensitivity to rosiglitazone. Weight loss also enhanced the expression of adiponectin and leptin while reducing that of monocyte chemoattractant protein 1 and interleukin-8 by cultured adipocytes. Thus, the weight-reducing (DI) increased adipogenic capacity of preadipocytes and shifted their secretion toward lower inflammatory profile. Reprogramming of preadipocytes could represent an adaptation to weight loss leading to partial restoration of preobese adipose tissue traits and thus contribute to the improvement of metabolic status. However, enhanced adipogenesis could also contribute to the unwanted weight regain after initial weight loss.
- MeSH
- adipogeneze genetika fyziologie MeSH
- adiponektin metabolismus MeSH
- chemokin CCL2 metabolismus MeSH
- cytokiny metabolismus MeSH
- ELISA MeSH
- hmotnostní úbytek genetika fyziologie MeSH
- interleukin-8 metabolismus MeSH
- kultivované buňky MeSH
- leptin metabolismus MeSH
- lidé MeSH
- obezita MeSH
- PPAR gama metabolismus MeSH
- thiazolidindiony farmakologie MeSH
- tukové buňky cytologie MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- adipogeneze genetika MeSH
- adipokiny genetika MeSH
- celogenomová asociační studie MeSH
- energetický metabolismus genetika MeSH
- fenotyp MeSH
- genetická predispozice k nemoci MeSH
- genetické asociační studie MeSH
- hypothalamus MeSH
- index tělesné hmotnosti MeSH
- lidé MeSH
- mitochondrie MeSH
- modely u zvířat MeSH
- obezita * etiologie genetika vrozené MeSH
- polymorfismus genetický MeSH
- pozorovací studie jako téma MeSH
- receptor inzulinu genetika MeSH
- tuková tkáň MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- klinické zkoušky MeSH
