The molecular mechanisms linking obstructive sleep apnea syndrome (OSA) to obesity and the development of metabolic diseases are still poorly understood. The role of hypoxia (a characteristic feature of OSA) in excessive fat accumulation has been proposed. The present study investigated the possible effects of hypoxia (4% oxygen) on de novo lipogenesis by tracking the major carbon sources in differentiating 3T3-L1 adipocytes. Gas-permeable cultuware was employed to cultivate 3T3-L1 adipocytes in hypoxia (4%) for 7 or 14 days of differentiation. We investigated the contribution of glutamine, glucose or acetate using 13C or 14C labelled carbons to the newly synthesized lipid pool, changes in intracellular lipid content after inhibiting citrate- or acetate-dependent pathways and gene expression of involved key enzymes. The results demonstrate that, in differentiating adipocytes, hypoxia decreased the synthesis of lipids from glucose (44.1 ± 8.8 to 27.5 ± 3.0 pmol/mg of protein, p < 0.01) and partially decreased the contribution of glutamine metabolized through the reverse tricarboxylic acid cycle (4.6% ± 0.2-4.2% ± 0.1%, p < 0.01). Conversely, the contribution of acetate, a citrate- and mitochondria-independent source of carbons, increased upon hypoxia (356.5 ± 71.4 to 649.8 ± 117.5 pmol/mg of protein, p < 0.01). Further, inhibiting the citrate- or acetate-dependent pathways decreased the intracellular lipid content by 58% and 73%, respectively (p < 0.01) showing the importance of de novo lipogenesis in hypoxia-exposed adipocytes. Altogether, hypoxia modified the utilization of carbon sources, leading to alterations in de novo lipogenesis in differentiating adipocytes and increased intracellular lipid content.
- MeSH
- acetáty * metabolismus farmakologie MeSH
- buněčná diferenciace * účinky léků MeSH
- buňky 3T3-L1 * MeSH
- citrátový cyklus MeSH
- glukosa * metabolismus MeSH
- glutamin * metabolismus MeSH
- hypoxie buňky MeSH
- lipidy biosyntéza MeSH
- lipogeneze * účinky léků MeSH
- metabolismus lipidů účinky léků MeSH
- myši MeSH
- tukové buňky * metabolismus účinky léků MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Lipodystrofické syndromy jsou heterogenní skupinou vzácných onemocnění spojených se ztrátou podkožní tukové tkáně různého rozsahu, která vede k závažným metabolickým komplikacím – hypertriglyceridemii, steatóze jater a zejména inzulinové rezistenci. Tyto komplikace mohou zkracovat život. V důsledku chybění tukové tkáně dochází k deficitu adipokinů, zejména leptinu. V léčbě lipodystrofických syndromů se uplatňuje konvenční složka – standardní léčba metabolických komplikací, ale také nedávno zavedené podávání rekombinantního leptinu.(metreleptinu) který kompenzuje leptinový deficit. Jeho podávání významně zlepšuje klinický stav pacientů a jejich metabolické komplikace. Uplatňuje se v léčení jak generalizované, tak i parciální lipodystrofie.
Lipodystrophy syndromes represent a heterogeneous group of rare diseases characterized by various degree of adipose tissue loss that results in severe metabolic complications, including hypertriglyceridemia, steatohepatitis and particularly insulin resistance. These complications may increase the mortality rate. Adipokine deficiency, and especially leptin deficiency, is due to fat tissue loss. Therapy for lipodystrophy primarily consists of a conventional approach that involves standard treatments of metabolic abnormalities. Recently, recombinant leptin.(metreleptin) administration has been introduced to compensate for leptin deficiency. This therapy markedly improves the overall patients’ status and metabolic complications and was approved for the treatment of both generalized and partial lipodystrophy.
- MeSH
- dítě MeSH
- inzulinová rezistence genetika MeSH
- kvalita života MeSH
- leptin farmakologie klasifikace terapeutické užití MeSH
- lidé MeSH
- lipodystrofie * diagnóza farmakoterapie klasifikace komplikace vrozené MeSH
- podkožní tuk metabolismus patologie MeSH
- tukové buňky metabolismus patologie MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- Publikační typ
- přehledy MeSH
Tukové tkanivo je dynamický metabolický orgán, ktorý zabezpečuje metabolickú homeostázu organizmu. Sekrécia adipocytokínov závisí od distribúcie tukového tkaniva, ako aj bunkového zloženia samotného tukového tkaniva – dôležitý je podiel adipocytov, stromálnych buniek, ciev a buniek imunitného systému. Cieľom našich prác, ktoré dokumentuje tento článok, je zistiť vplyv vybraných adipocytokínov na metabolické a imunologické komplikácie po transplantácii obličky. V našich analýzach sme nepotvrdili vplyv chronickej imunosupresie na hladiny adiponektínu a leptínu. Zistili sme však, že vyššie hladiny leptínu predikovali vývoj potransplantačného diabetes mellitus a nízke hladiny adiponektínu boli spojené s obezitou. Taktiež sme potvrdili, že hyperleptinemia je spojená s rozvojom akútnej rejekcie štepu a tvorbou donor špecifických protilátok.
Adipose tissue is a dynamic metabolic organ that regulates the metabolic homeostasis of the body. The secretion of adipocytokines depends on the distribution of adipose tissue, as well as the cellular composition of the adipose tissue itself - the proportion of adipocytes, stromal cells, blood vessels and cells of the immune system is important. In our analyses, the effect of chronic immunosuppression on adiponectin and leptin levels has not been confirmed. However, we found that higher leptin levels predicted the development of post-transplant diabetes mellitus and low adiponectin levels were associated with obesity and insulin resistance. It was also confirmed that hyperleptinemia is associated with the development of acute graft rejection and the formation of donor specific antibodies.
- MeSH
- adiponektin škodlivé účinky MeSH
- leptin škodlivé účinky MeSH
- lidé MeSH
- rejekce štěpu etiologie MeSH
- rizikové faktory MeSH
- transplantace ledvin * MeSH
- tukové buňky * imunologie metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
The increasing use of industrial chemicals has raised concerns regarding exposure to endocrine-disrupting chemicals (EDCs), which interfere with developmental, reproductive and metabolic processes. Of particular concern is their interaction with adipose tissue, a vital component of the endocrine system regulating metabolic and hormonal functions. The SGBS (Simpson Golabi Behmel Syndrome) cell line, a well-established human-relevant model for adipocyte research, closely mimics native adipocytes' properties. It responds to hormonal stimuli, undergoes adipogenesis and has been successfully used to study the impact of EDCs on adipose biology. In this study, we screened human exposure-relevant doses of various EDCs on the SGBS cell line to investigate their effects on viability, lipid accumulation and adipogenesis-related protein expression. Submicromolar doses were generally well tolerated; however, at higher doses, EDCs compromised cell viability, with cadmium chloride (CdCl2) showing the most pronounced effects. Intracellular lipid levels remained unaffected by EDCs, except for tributyltin (TBT), used as a positive control, which induced a significant increase. Analysis of adipogenesis-related protein expression revealed several effects, including downregulation of fatty acid-binding protein 4 (FABP4) by dibutyl phthalate, upregulation by CdCl2 and downregulation of perilipin 1 and FABP4 by perfluorooctanoic acid. Additionally, TBT induced dose-dependent upregulation of C/EBPα, perilipin 1 and FABP4 protein expression. These findings underscore the importance of employing appropriate models to study EDC-adipocyte interactions. Conclusions from this research could guide strategies to reduce the negative impacts of EDC exposure on adipose tissue.
- MeSH
- adipogeneze * účinky léků MeSH
- buněčné linie MeSH
- endokrinní disruptory * toxicita MeSH
- fluorokarbony toxicita MeSH
- kapryláty toxicita MeSH
- lidé MeSH
- metabolismus lipidů účinky léků MeSH
- proteiny vázající mastné kyseliny * metabolismus genetika MeSH
- trialkylcínové sloučeniny toxicita MeSH
- tuková tkáň účinky léků metabolismus MeSH
- tukové buňky účinky léků metabolismus MeSH
- viabilita buněk * účinky léků MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
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
Adipose tissue signals to brain, liver, and muscles to control whole body metabolism through secreted lipid and protein factors as well as neurotransmission, but the mechanisms involved are incompletely understood. Adipocytes sequester triglyceride (TG) in fed conditions stimulated by insulin, while in fasting catecholamines trigger TG hydrolysis, releasing glycerol and fatty acids (FAs). These antagonistic hormone actions result in part from insulin's ability to inhibit cAMP levels generated through such G-protein-coupled receptors as catecholamine-activated β-adrenergic receptors. Consistent with these antagonistic signaling modes, acute actions of catecholamines cause insulin resistance. Yet, paradoxically, chronically activating adipocytes by catecholamines cause increased glucose tolerance, as does insulin. Recent results have helped to unravel this conundrum by revealing enhanced complexities of these hormones' signaling networks, including identification of unexpected common signaling nodes between these canonically antagonistic hormones.
- MeSH
- AMP cyklický metabolismus MeSH
- inzulin * metabolismus MeSH
- katecholaminy metabolismus MeSH
- lidé MeSH
- lipolýza * fyziologie MeSH
- tuková tkáň metabolismus MeSH
- tukové buňky metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
OBJECTIVES: Nuclear receptor interacting protein 1 (NRIP1) suppresses energy expenditure via repression of nuclear receptors, and its depletion markedly elevates uncoupled respiration in mouse and human adipocytes. We tested whether NRIP1 deficient adipocytes implanted into obese mice would enhance whole body metabolism. Since β-adrenergic signaling through cAMP strongly promotes adipocyte thermogenesis, we tested whether the effects of NRIP1 knock-out (NRIP1KO) require the cAMP pathway. METHODS: NRIP1KO adipocytes were implanted in recipient high-fat diet (HFD) fed mice and metabolic cage studies conducted. The Nrip1 gene was disrupted by CRISPR in primary preadipocytes isolated from control vs adipose selective GsαKO (cAdGsαKO) mice prior to differentiation to adipocytes. Protein kinase A inhibitor was also used. RESULTS: Implanting NRIP1KO adipocytes into HFD fed mice enhanced whole-body glucose tolerance by increasing insulin sensitivity, reducing adiposity, and enhancing energy expenditure in the recipients. NRIP1 depletion in both control and GsαKO adipocytes was equally effective in upregulating uncoupling protein 1 (UCP1) and adipocyte beiging, while β-adrenergic signaling by CL 316,243 was abolished in GsαKO adipocytes. Combining NRIP1KO with CL 316,243 treatment synergistically increased Ucp1 gene expression and increased the adipocyte subpopulation responsive to beiging. Estrogen-related receptor α (ERRα) was dispensable for UCP1 upregulation by NRIPKO. CONCLUSIONS: The thermogenic effect of NRIP1 depletion in adipocytes causes systemic enhancement of energy expenditure when such adipocytes are implanted into obese mice. Furthermore, NRIP1KO acts independently but cooperatively with the cAMP pathway in mediating its effect on adipocyte beiging.
- MeSH
- lidé MeSH
- myši obézní MeSH
- myši MeSH
- nuclear receptor interacting protein 1 metabolismus MeSH
- obezita metabolismus MeSH
- signální transdukce * MeSH
- termogeneze genetika MeSH
- tukové buňky * metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Research Support, N.I.H., Intramural MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
Disruption of adipocyte de novo lipogenesis (DNL) by deletion of fatty acid synthase (FASN) in mice induces browning in inguinal white adipose tissue (iWAT). However, adipocyte FASN knockout (KO) increases acetyl-coenzyme A (CoA) and malonyl-CoA in addition to depletion of palmitate. We explore which of these metabolite changes triggers adipose browning by generating eight adipose-selective KO mouse models with loss of ATP-citrate lyase (ACLY), acetyl-CoA carboxylase 1 (ACC1), ACC2, malonyl-CoA decarboxylase (MCD) or FASN, or dual KOs ACLY/FASN, ACC1/FASN, and ACC2/FASN. Preventing elevation of acetyl-CoA and malonyl-CoA by depletion of adipocyte ACLY or ACC1 in combination with FASN KO does not block the browning of iWAT. Conversely, elevating malonyl-CoA levels in MCD KO mice does not induce browning. Strikingly, adipose ACC1 KO induces a strong iWAT thermogenic response similar to FASN KO while also blocking malonyl-CoA and palmitate synthesis. Thus, ACC1 and FASN are strong suppressors of adipocyte thermogenesis through promoting lipid synthesis rather than modulating the DNL intermediates acetyl-CoA or malonyl-CoA.
- MeSH
- acetyl-CoA-karboxylasa * metabolismus MeSH
- acetylkoenzym A metabolismus MeSH
- myši knockoutované MeSH
- myši MeSH
- palmitany metabolismus MeSH
- syntázy mastných kyselin metabolismus MeSH
- termogeneze MeSH
- tukové buňky * metabolismus MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Research Support, N.I.H., Extramural MeSH
BACKGROUND: Dysfunctional adipose tissue (AT) is known to contribute to the pathophysiology of metabolic disease, including type 2 diabetes mellitus (T2DM). This dysfunction may occur, in part, as a consequence of gut-derived endotoxaemia inducing changes in adipocyte mitochondrial function and reducing the proportion of BRITE (brown-in-white) adipocytes. Therefore, the present study investigated whether endotoxin (lipopolysaccharide; LPS) directly contributes to impaired human adipocyte mitochondrial function and browning in human adipocytes, and the relevant impact of obesity status pre and post bariatric surgery. METHODS: Human differentiated abdominal subcutaneous (AbdSc) adipocytes from participants with obesity and normal-weight participants were treated with endotoxin to assess in vitro changes in mitochondrial function and BRITE phenotype. Ex vivo human AbdSc AT from different groups of participants (normal-weight, obesity, pre- and 6 months post-bariatric surgery) were assessed for similar analyses including circulating endotoxin levels. RESULTS: Ex vivo AT analysis (lean & obese, weight loss post-bariatric surgery) identified that systemic endotoxin negatively correlated with BAT gene expression (p < 0.05). In vitro endotoxin treatment of AbdSc adipocytes (lean & obese) reduced mitochondrial dynamics (74.6% reduction; p < 0.0001), biogenesis (81.2% reduction; p < 0.0001) and the BRITE phenotype (93.8% reduction; p < 0.0001). Lean AbdSc adipocytes were more responsive to adrenergic signalling than obese AbdSc adipocytes; although endotoxin mitigated this response (92.6% reduction; p < 0.0001). CONCLUSIONS: Taken together, these data suggest that systemic gut-derived endotoxaemia contributes to both individual adipocyte dysfunction and reduced browning capacity of the adipocyte cell population, exacerbating metabolic consequences. As bariatric surgery reduces endotoxin levels and is associated with improving adipocyte functionality, this may provide further evidence regarding the metabolic benefits of such surgical interventions.
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.
