RESUMO
This study aimed to comprehensively assess the metabolic, mitochondrial, and inflammatory effects of first-line efavirenz, emtricitabine, and tenofovir disoproxil fumarate (EFV/FTC/TDF) single-tablet regimen (STR) relative to untreated asymptomatic HIV infection. To this end, we analyzed 29 people with HIV (PWH) treated for at least one year with this regimen vs. 33 antiretroviral-naïve PWH. Excellent therapeutic activity was accompanied by significant alterations in metabolic parameters. The treatment group showed increased plasmatic levels of glucose, total cholesterol and its fractions (LDL and HDL), triglycerides, and hepatic enzymes (GGT, ALP); conversely, bilirubin levels (total and indirect fraction) decreased in the treated cohort. Mitochondrial performance was preserved overall and treatment administration even promoted the recovery of mitochondrial DNA (mtDNA) content depleted by the virus, although this was not accompanied by the recovery in some of their encoded proteins (since cytochrome c oxidase II was significantly decreased). Inflammatory profile (TNFα, IL-6), ameliorated after treatment in accordance with viral reduction and the recovery of TNFα levels correlated to mtDNA cell restoration. Thus, although this regimen causes subclinical metabolic alterations, its antiviral and anti-inflammatory properties may be associated with partial improvement in mitochondrial function.
Assuntos
Alcinos , Fármacos Anti-HIV , Benzoxazinas , Ciclopropanos , DNA Mitocondrial , Emtricitabina , Infecções por HIV , Mitocôndrias , Tenofovir , Humanos , Infecções por HIV/tratamento farmacológico , Infecções por HIV/metabolismo , Masculino , Feminino , Adulto , Mitocôndrias/metabolismo , Mitocôndrias/efeitos dos fármacos , Benzoxazinas/uso terapêutico , Benzoxazinas/farmacologia , Fármacos Anti-HIV/uso terapêutico , Fármacos Anti-HIV/efeitos adversos , Ciclopropanos/uso terapêutico , Tenofovir/uso terapêutico , Pessoa de Meia-Idade , Emtricitabina/uso terapêutico , DNA Mitocondrial/metabolismo , InflamaçãoRESUMO
Fibroblast growth factor-21 (FGF21) is a hormonal regulator of metabolism; it promotes glucose oxidation and the thermogenic capacity of adipose tissues. The levels of ß-klotho (KLB), the co-receptor required for FGF21 action, are decreased in brown (BAT) and white (WAT) adipose tissues during obesity, diabetes, and lipodystrophy. Reduced ß-klotho levels have been proposed to account for FGF21 resistance in these conditions. In this study, we explored whether downregulation of ß-klotho affects metabolic regulation and the thermogenic responsiveness of adipose tissues using mice with total (KLB-KO) or partial (KLB-heterozygotes) ablation of ß-klotho. We herein show that KLB gene dosage was inversely associated with adiposity in mice. Upon cold exposure, impaired browning of subcutaneous WAT and milder alterations in BAT were associated with reduced KLB gene dosage in mice. Cultured brown and beige adipocytes from mice with total or partial ablation of the KLB gene showed reduced thermogenic responsiveness to ß3-adrenergic activation by treatment with CL316,243, indicating that these effects were cell-autonomous. Deficiency in FGF21 mimicked the KLB-reduction-induced impairment of thermogenic responsiveness in brown and beige adipocytes. These results indicate that the levels of KLB in adipose tissues determine their thermogenic capacity to respond to cold and/or adrenergic stimuli. Moreover, an autocrine action of FGF21 in brown and beige adipocytes may account for the ability of the KLB level to influence thermogenic responsiveness.NEW & NOTEWORTHY Reduced levels of KLB (the obligatory FGF21 co-receptor), as occurring in obesity and type 2 diabetes, reduce the thermogenic responsiveness of adipose tissues in cold-exposed mice. Impaired response to ß3-adrenergic activation in brown and beige adipocytes with reduced KLB occurs in a cell-autonomous manner involving an autocrine action of FGF21.
Assuntos
Tecido Adiposo/metabolismo , Fatores de Crescimento de Fibroblastos/fisiologia , Proteínas de Membrana/fisiologia , Termogênese/genética , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Marrom/metabolismo , Adiposidade/genética , Animais , Comunicação Autócrina/efeitos dos fármacos , Comunicação Autócrina/genética , Células Cultivadas , Fatores de Crescimento de Fibroblastos/farmacologia , Dosagem de Genes/fisiologia , Proteínas Klotho , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Termogênese/efeitos dos fármacosRESUMO
Chemokine (C-X-C motif) ligand-14 (CXCL14) levels are downregulated in experimental rodent models of obesity. Moreover, CXCL14 reportedly favors insulin sensitization in obese mice. Here we examined, for the first time, the role of CXCL14 in human obesity. We found that circulating levels of CXCL14 were decreased in patients with obesity and, especially, those with concomitant type-2 diabetes. CXCL14 levels were negatively associated with BMI and with indices of impaired glucose/insulin homeostasis. CXCL14 expression was decreased in subcutaneous adipose tissue from patients with obesity and type-2 diabetes. In adipose tissue, CXCL14 expression was negatively correlated with the expression of genes encoding pro-inflammatory molecules, and positively correlated with GLUT4 and adiponectin expression. In conclusion, obesity, and especially, concomitant type-2 diabetes are associated with abnormally decreased levels of CXCL14 in blood and impaired CXCL14 expression in adipose tissue. CXCL14 downregulation may be a novel biomarker of altered metabolism in obesity. CXCL14 also deserves further research as a therapeutic candidate.
Assuntos
Quimiocinas CXC/sangue , Diabetes Mellitus Tipo 2 , Obesidade , Tecido Adiposo/química , Tecido Adiposo/metabolismo , Quimiocinas CXC/análise , Quimiocinas CXC/metabolismo , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/epidemiologia , Humanos , Obesidade/sangue , Obesidade/complicações , Obesidade/epidemiologiaRESUMO
Parkin is an ubiquitin-E3 ligase that acts as a key component of the cellular machinery for mitophagy. We show here that Parkin expression is reciprocally regulated in brown adipose tissue in relation to thermogenic activity. Thermogenic stimuli repress Parkin gene expression via transcriptional mechanisms that are elicited by noradrenergic and PPARα-mediated pathways that involve intracellular lipolysis in brown adipocytes. Parkin-KO mice show over-activated brown adipose tissue thermogenic activity and exhibit improved metabolic parameters, especially when fed a high-fat diet. Deacclimation, which is the return of a cold-adapted mouse to a thermoneutral temperature, dramatically induces mitophagy in brown adipocytes, with a concomitant induction of Parkin levels. We further reveal that Parkin-KO mice exhibit defects in the degradative processing of mitochondrial proteins in brown adipose tissue in response to deacclimation. These results suggest that the transcriptional control of Parkin in brown adipose tissue may contribute to modulating the mitochondrial mass and activity for adaptation to thermogenic requirements.
Assuntos
Tecido Adiposo Marrom/metabolismo , Plasticidade Celular/fisiologia , Termogênese/fisiologia , Ubiquitina-Proteína Ligases/metabolismo , Adipócitos Marrons , Animais , Dieta Hiperlipídica , Regulação da Expressão Gênica/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias/metabolismo , Mitofagia/fisiologia , Transcrição Gênica/fisiologiaRESUMO
In this article, we investigated the inâ vitro potential beneficial effects of the anthocyanin cyanidin-3-O-glucoside (C3G) on inflammation and insulin resistance markers induced by palmitic acid (PA) in human SGBS adipocytes. Results demonstrated that PA reduced insulin sensitivity in SGBS cells with a significant inhibition of Akt phosphorylation, with a higher sensitivity to PA than murine 3T3-L1 adipocytes, GLUT-1 and GLUT-4 glucose transporters and the enzyme hexokinase-II. C3G pretreatment (1-20â µM) reverted these effects. Moreover, we demonstrated, for the first time in human adipocytes, that cells exposure to PA induced gene expression of proinflammatory cytokines TNF-α, IL-6, IL-8, and MCP-1. Cells pretreatment with C3G resulted in a reduction in mRNA levels starting at very low concentrations (1â µM). In conclusion, this study highlights the effects of PA on inflammation and insulin resistance markers in human adipocytes, and confirm the role of C3G in the prevention of lipotoxicity in dysfunctional adipocytes.
Assuntos
Adipócitos/efeitos dos fármacos , Antocianinas/farmacologia , Citocinas/genética , Inflamação/tratamento farmacológico , Ácido Palmítico/farmacologia , Células 3T3-L1 , Animais , Antocianinas/química , Relação Dose-Resposta a Droga , Humanos , Inflamação/metabolismo , CamundongosRESUMO
Adaptive induction of thermogenesis in brown adipose tissue (BAT) is essential for the survival of mammals after birth. We show here that G protein-coupled receptor protein 120 (GPR120) expression is dramatically induced after birth in mouse BAT. GPR120 expression in neonatal BAT is the highest among GPR120-expressing tissues in the mouse at any developmental stage tested. The induction of GPR120 in neonatal BAT is caused by postnatal thermal stress rather than by the initiation of suckling. GPR120-null neonates were found to be relatively intolerant to cold: close to one-third did not survive at 21°C, but all such pups survived at 25°C. Heat production in BAT was significantly impaired in GPR120-null pups. Deficiency in GPR120 did not modify brown adipocyte morphology or the anatomical architecture of BAT, as assessed by electron microscopy, but instead impaired the expression of uncoupling protein-1 and the fatty acid oxidation capacity of neonatal BAT. Moreover, GPR120 deficiency impaired fibroblast growth factor 21 (FGF21) gene expression in BAT and reduced plasma FGF21 levels. These results indicate that GPR120 is essential for neonatal adaptive thermogenesis.
Assuntos
Tecido Adiposo Marrom/fisiologia , Animais Recém-Nascidos/fisiologia , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/fisiologia , Termogênese/fisiologia , Animais , Temperatura Baixa , Ácidos Graxos/metabolismo , Feminino , Fatores de Crescimento de Fibroblastos , Glucose/metabolismo , Transtornos de Estresse por Calor/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Oxirredução , Palmitatos/metabolismo , Proteína Desacopladora 1/metabolismoRESUMO
Following antiretroviral therapy, HIV-infected patients show increased circulating levels of the antidiabetic hormone fibroblast growth factor 21 (FGF21). In contrast, the expression of the FGF21-obligatory coreceptor ß-Klotho (KLB) is reduced in target tissues. This situation is comparable to the FGF21 resistance status observed in obesity and type 2 diabetes. Here, we performed the first systematic study of the effects of distinct members of different antiretroviral drug classes on the FGF21/KLB system in human hepatic, adipose, and skeletal muscle cells. Most protease inhibitors and the nonnucleoside reverse transcriptase inhibitor efavirenz induced FGF21 gene expression. Neither nucleoside reverse transcriptase inhibitors nor the viral entry inhibitor maraviroc had any effect. Among the integrase inhibitors, elvitegravir significantly induced FGF21 expression, whereas raltegravir had minor effects only in adipose cells. In human hepatocytes and adipocytes, known target cells of FGF21 action, efavirenz, elvitegravir, and the lopinavir-ritonavir combination exerted inhibitory effects on KLB gene expression. Drug treatments that elicited FGF21 induction/KLB repression were those found to induce endoplasmic reticulum (ER) stress and oxidative stress. Notably, the pharmacological agents thapsigargin and tunicamycin, which induce these stress pathways, mimicked the effects of drug treatments. Moreover, pharmacological inhibitors of either ER or oxidative stress significantly impaired lopinavir-ritonavir-induced regulation of FGF21, but not KLB. In conclusion, the present in vitro screen study identifies the antiretroviral drugs that affect FGF21/KLB expression in human cells. The present results could have important implications for the management of comorbidities resulting from side effects of specific antiretroviral drugs for the treatment of HIV-infected patients.
Assuntos
Tecido Adiposo/metabolismo , Antirretrovirais/farmacologia , Fatores de Crescimento de Fibroblastos/análise , Infecções por HIV/tratamento farmacológico , Fígado/metabolismo , Proteínas de Membrana/análise , Músculo Esquelético/metabolismo , Alcinos , Benzoxazinas/farmacologia , Ciclopropanos , Diabetes Mellitus Tipo 2/patologia , Combinação de Medicamentos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Inibidores de Integrase de HIV/farmacologia , Células Hep G2 , Humanos , Proteínas Klotho , Lopinavir/farmacologia , Maraviroc/farmacologia , Obesidade/patologia , Estresse Oxidativo/efeitos dos fármacos , Inibidores de Proteases/farmacologia , Quinolonas/farmacologia , Inibidores da Transcriptase Reversa/farmacologia , Ritonavir/farmacologia , Tapsigargina/farmacologia , Tunicamicina/farmacologiaRESUMO
The physiological regulation of hepatic glutathione efflux by catecholamines is poorly understood. The purpose of this work was to review the role of adrenergic receptors (AR) on total glutathione (GT) efflux in rat liver. Two models were used: isolated hepatocytes and perfused livers. In hepatocytes 10⯵M adrenaline (Adr), but not isoproterenol (Iso) a ß-AR agonist, or phenylephrine (Phe) an α1-AR agonist, (in a Krebs-Henseleit buffer (KHB) enriched with Ca2+ and some aminoacids) increased in 13% GT efflux. In livers perfused with KHB, Adr or Iso at 1 µmolar doses (but not Phe) stimulated 11-fold initial velocity of GT release, but only during the first 2â¯min of perfusion. This immediate response progressively disappeared during the following 15â¯min of perfusion. A second phase of GT efflux, observed between 2 and 14â¯min of perfusion, mimics the one reported earlier in isolated hepatocytes. The ED50 for Adr and Iso activation are in the range of 320â¯nM and 10â¯nM, respectively. Iso-mediated GT release requires Ca2+ to work, and was prevented by H89, glibenclamide, cystic fibrosis transmembrane regulator (CFTR) antibodies, and a direct CFTR inhibitor. This short-lived GT release system is associated to PKA activation and probably operates through CFTR.
Assuntos
Glutationa/metabolismo , Hepatócitos/metabolismo , Fígado/metabolismo , Receptores Adrenérgicos beta/metabolismo , Agonistas de Receptores Adrenérgicos alfa 1/farmacologia , Agonistas Adrenérgicos beta/farmacologia , Animais , Hepatócitos/citologia , Isoproterenol/farmacologia , Fígado/citologia , Masculino , Fenilefrina/farmacologia , Ratos , Ratos Wistar , Receptores Adrenérgicos alfa 1/metabolismoRESUMO
AIMS/HYPOTHESIS: Adipocyte lipopolysaccharide-binding protein (LBP) biosynthesis is associated with obesity-induced adipose tissue dysfunction. Our purpose was to study the role of LBP in regulating the browning of adipose tissue. METHODS: Adult mice were maintained at 4°C for 3 weeks or treated with the ß3-adrenergic agonist, CL316,243, for 1 week to induce the browning of white fat. Precursor cells from brown and white adipose tissues were cultured under differentiation-inducing conditions to yield brown and beige/brite adipocytes, respectively. In vitro, Lbp was knocked down in 3T3-L1 adipocytes, and cells were treated with recombinant LBP or co-cultured in transwells with control 3T3-L1 adipocytes. Wild-type and Lbp-null mice, fed a standard or high fat diet (HFD) for 15 weeks, were also used in investigations. In humans, subcutaneous and visceral adipose tissue samples were obtained from a cohort of morbidly obese participants. RESULTS: The induction of white fat browning by exposure of mice to cold or CL316,243 treatment was strongly associated with decreased Lbp mRNA expression in white adipose tissue. The acquisition of the beige/brite phenotype in cultured cells was associated with downregulation of Lbp. Moreover, silencing of Lbp induced the expression of brown fat-related genes in adipocytes, whereas LBP treatment reversed this effect. Lbp-null mice exhibited the spontaneous induction of subcutaneous adipose tissue browning, as evidenced by a remarkable increase in Ucp1 and Dio2 gene expression and the appearance of multivacuolar adipocyte clusters. The amount of brown adipose tissue, and brown adipose tissue activity were also increased in Lbp-null mice. These changes were associated with decreased weight gain in Lbp-null mice and protection against HFD-induced inflammatory responses, as shown by reduced IL-6 levels. However, rather than improving glucose homeostasis, these effects led to glucose intolerance and insulin resistance. CONCLUSIONS/INTERPRETATION: LBP is identified as a negative regulator of the browning process, which is likely to contribute to the obesity-promoting action of LBP. The deleterious metabolic effects of LBP deletion are compatible with the concept that the appropriate regulation of inflammatory pathways is necessary for a healthy systemic metabolic profile, regardless of body weight regulation.
Assuntos
Proteínas de Fase Aguda/metabolismo , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , Proteínas de Transporte/metabolismo , Glicoproteínas de Membrana/metabolismo , Obesidade Mórbida/metabolismo , Células 3T3-L1 , Proteínas de Fase Aguda/genética , Animais , Western Blotting , Proteínas de Transporte/genética , Células Cultivadas , Técnicas de Cocultura , Dieta Hiperlipídica/efeitos adversos , Fatores de Crescimento de Fibroblastos/genética , Fatores de Crescimento de Fibroblastos/metabolismo , Iodeto Peroxidase/genética , Iodeto Peroxidase/metabolismo , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Obesidade Mórbida/genética , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Sirtuína 3/genética , Sirtuína 3/metabolismo , Proteína Desacopladora 1/genética , Proteína Desacopladora 1/metabolismo , Iodotironina Desiodinase Tipo IIRESUMO
The ability of alternative splicing mechanisms to control gene expression is increasingly being recognized as relevant for adipose tissue function. The expression of SF3B1, a key component of the SF3B complex directly involved in spliceosome formation, was previously reported to be significantly induced in brown adipose tissue under cold-induced thermogenic activation. Here, we identify that noradrenergic cAMP-mediated thermogenic stimulation increases SF3B1 expression in brown and beige adipocytes. We further show that pladienolide-B, a drug that binds SF3B1 to inhibit pre-mRNA splicing by targeting the SF3B complex, down-regulates key components of the thermogenic machinery (e.g., UCP1 gene expression), differentially alters the expression of alternative splicing-regulated transcripts encoding molecular actors involved in the oxidative metabolism of brown adipocytes (e.g., peroxisome proliferator-activated receptor-gamma co-activator-alpha [PGC-1α] and cytochrome oxidase subunit 7a genes), and impairs the respiratory activity of brown adipocytes. Similar alterations were found in brown adipocytes with siRNA-mediated knockdown of SF3B1 protein levels. Our findings collectively indicate that SF3B1 is a key factor in the appropriate thermogenic activation of differentiated brown adipocytes. This work exemplifies the importance of splicing processes in adaptive thermogenesis and suggests that pharmacological tools, such as pladienolide-B, may be used to modulate brown adipocyte thermogenic activity.
Assuntos
Adipócitos Marrons , Regulação da Expressão Gênica , Adipócitos Marrons/metabolismo , Fatores de Processamento de RNA/genética , Fatores de Processamento de RNA/metabolismo , Fatores de Transcrição/metabolismo , Tecido Adiposo Marrom/metabolismo , Termogênese/fisiologia , Proteína Desacopladora 1/genética , Proteína Desacopladora 1/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genéticaRESUMO
Introduction: Meteorin-like (METRNL) is a hormonal factor released by several tissues, including thermogenically active brown and beige adipose tissues. It exerts multiple beneficial effects on metabolic and cardiovascular systems in experimental models. However, the potential role of METRNL as brown adipokine in humans has not been investigated previously, particularly in relation to the metabolic adaptations taking place in early life, when brown adipose tissue (BAT) is particularly abundant. Methods and materials: METRNL levels, as well as body composition (DXA) and circulating endocrine-metabolic variables, were assessed longitudinally in a cohort of infants at birth, and at ages 4 and 12 months. BAT activity was measured by infrared thermography at age 12 months. METRNL levels were also determined cross-sectionally in adults; METRNL gene expression (qRT-PCR) was assessed in BAT and liver samples from neonates, and in adipose tissue and liver samples form adults. Simpson-Golabi-Behmel Syndrome (SGBS) adipose cells were thermogenically activated using cAMP, and METRNL gene expression and METRNL protein released were analysed. Results: Serum METRNL levels were high at birth and declined across the first year of life albeit remaining higher than in adulthood. At age 4 and 12 months, METRNL levels correlated positively with circulating C-X-C motif chemokine ligand 14 (CXCL14), a chemokine released by thermogenically active BAT, but not with parameters of adiposity or metabolic status. METRNL levels also correlated positively with infrared thermography-estimated posterior-cervical BAT activity in girls aged 12 months. Gene expression analysis indicated high levels of METRNL mRNA in neonatal BAT. Thermogenic stimulus of brown/beige adipocytes led to a significant increase of METRNL gene expression and METRN protein release to the cell culture medium. Conclusion: Circulating METRNL levels are high in the first year of life and correlate with indices of BAT activity and with levels of an established brown adipokine such as CXCL14. These data, in addition with the high expression of METRNL in neonatal BAT and in thermogenically-stimulated brown/beige adipocytes, suggest that METRNL is actively secreted by BAT and may be a circulating biomarker of BAT activity in early life.
Assuntos
Adipócitos Marrons , Tecido Adiposo Marrom , Adulto , Feminino , Recém-Nascido , Lactente , Humanos , Tecido Adiposo Marrom/metabolismo , Adipócitos Marrons/metabolismo , Obesidade/metabolismo , Tecido Adiposo Bege/metabolismo , Quimiocinas CXC/metabolismoRESUMO
Adipose tissue from pheochromocytoma patients acquires brown fat features, making it a valuable model for studying the mechanisms that control thermogenic adipose plasticity in humans. Transcriptomic analyses revealed a massive downregulation of splicing machinery components and splicing regulatory factors in browned adipose tissue from patients, with upregulation of a few genes encoding RNA-binding proteins potentially involved in splicing regulation. These changes were also observed in cell culture models of human brown adipocyte differentiation, confirming a potential involvement of splicing in the cell-autonomous control of adipose browning. The coordinated changes in splicing are associated with a profound modification in the expression levels of splicing-driven transcript isoforms for genes involved in the specialized metabolism of brown adipocytes and those encoding master transcriptional regulators of adipose browning. Splicing control appears to be a relevant component of the coordinated gene expression changes that allow human adipose tissue to acquire a brown phenotype.
RESUMO
OBJECTIVE: Maresin 1 (MaR1) is a docosahexaenoic acid-derived proresolving lipid mediator with insulin-sensitizing and anti-steatosis properties. Here, we aim to unravel MaR1 actions on brown adipose tissue (BAT) activation and white adipose tissue (WAT) browning. METHODS: MaR1 actions were tested in cultured murine brown adipocytes and in human mesenchymal stem cells (hMSC)-derived adipocytes. In vivo effects of MaR1 were tested in diet-induced obese (DIO) mice and lean WT and Il6 knockout (Il6-/-) mice. RESULTS: In cultured differentiated murine brown adipocytes, MaR1 reduces the expression of inflammatory genes, while stimulates glucose uptake, fatty acid utilization and oxygen consumption rate, along with the upregulation of mitochondrial mass and genes involved in mitochondrial biogenesis and function and the thermogenic program. In Leucine Rich Repeat Containing G Protein-Coupled Receptor 6 (LGR6)-depleted brown adipocytes using siRNA, the stimulatory effect of MaR1 on thermogenic genes was abrogated. In DIO mice, MaR1 promotes BAT remodeling, characterized by higher expression of genes encoding for master regulators of mitochondrial biogenesis and function and iBAT thermogenic activation, together with increased M2 macrophage markers. In addition, MaR1-treated DIO mice exhibit a better response to cold-induced BAT activation. Moreover, MaR1 induces a beige adipocyte signature in inguinal WAT of DIO mice and in hMSC-derived adipocytes. MaR1 potentiates Il6 expression in brown adipocytes and BAT of cold exposed lean WT mice. Interestingly, the thermogenic properties of MaR1 were abrogated in Il6-/- mice. CONCLUSIONS: These data reveal MaR1 as a novel agent that promotes BAT activation and WAT browning by regulating thermogenic program in adipocytes and M2 polarization of macrophages. Moreover, our data suggest that LGR6 receptor is mediating MaR1 actions on brown adipocytes, and that IL-6 is required for the thermogenic effects of MaR1.
Assuntos
Tecido Adiposo Marrom , Ácidos Docosa-Hexaenoicos , Camundongos , Humanos , Animais , Tecido Adiposo Marrom/metabolismo , Ácidos Docosa-Hexaenoicos/farmacologia , Ácidos Docosa-Hexaenoicos/metabolismo , Interleucina-6/metabolismo , Tecido Adiposo Branco/metabolismo , Adipócitos Marrons/metabolismoRESUMO
AIMS: To assess the potential direct effects of the integrase strand-transfer inhibitors (INsTIs) dolutegravir, bictegravir, and raltegravir, drugs used as treatment for people living with human immunodeficiency virus (PLWH), on human adipose cells. MAIN METHODS: Drugs were added to the differentiation medium of human Simpson-Golabi-Behmel syndrome (SGBS) adipose cells and morphological adipogenesis was monitored for 10 days. Also, adipocytes were exposed to drugs following differentiation (day 14). The gene expression levels of selected adipogenesis markers, adipocyte metabolism markers, adipokines, and cytokines were determined by quantitative-reverse transcription polymerase-chain reaction. The release of adiponectin and leptin into the culture medium was measured using specific enzyme-linked immunosorbent assay, and release of interleukin-6 and chemokine (CC motif) ligand-2 using Multiplex assays. KEY FINDINGS: Overall morphological adipogenesis was unaltered by INsTIs. The expression of adipogenesis marker genes (peroxisome proliferator-activated receptor-Æ and lipoprotein lipase) was slightly reduced in dolutegravir-treated differentiating adipocytes. Bictegravir repressed gene expression and the release of pro-inflammatory cytokines in differentiating adipocytes. Dolutegravir and raltegravir increased interleukin-6 gene expression, but only dolutegravir increased interleukin-6 release. Dolutegravir repressed adiponectin expression and release in differentiating adipocytes and had a similar but milder effect on leptin. Drug treatment of mature adipocytes reduced adiponectin gene expression in response to dolutegravir. SIGNIFICANCE: The INsTIs studied do not have a significant effect on human adipose cell differentiation but exert distinct effects on gene expression and secretion of adipokines and cytokines. These findings will help understand and manage the effects of INsTI-containing treatments on body weight and metabolic dysregulation in PLWH.
Assuntos
Adipocinas , Leptina , Adipócitos/metabolismo , Adipocinas/metabolismo , Adiponectina/metabolismo , Amidas , Citocinas/metabolismo , Compostos Heterocíclicos com 3 Anéis , Humanos , Inflamação/metabolismo , Integrases/metabolismo , Integrases/farmacologia , Interleucina-6/metabolismo , Leptina/metabolismo , Ligantes , Lipase Lipoproteica , Oxazinas , Receptores Ativados por Proliferador de Peroxissomo , Piperazinas , Piridonas , Raltegravir Potássico/metabolismo , Raltegravir Potássico/farmacologiaRESUMO
OBJECTIVE: CXCL14 (C-X-C motif chemokine ligand-14) is a chemokine released by active brown fat, showing protective effects against insulin resistance in experimental models. Polycystic ovary syndrome (PCOS) in adolescent girls is usually related to hepato-visceral fat excess and insulin resistance, and associates with comorbidities such as type 2 diabetes. Treatment with a low-dose combination of one antiandrogen and antimineralocorticoid drug (spironolactone) and two insulin sensitizers (pioglitazone/metformin) (SPIOMET) is particularly effective in improving these metabolic derangements. Adipose tissue may be involved in the metabolic alterations of PCOS, and it is a likely target of therapeutic action. We investigated the alterations in CXCL14 levels and the effects of drugs composing SPIOMET treatment on CXCL14 in human adipocytes. RESEARCH DESIGN AND METHODS: We studied 51 adolescent patients with PCOS and 21 age-matched healthy controls. Thirty-one adolescent patients with PCOS under SPIOMET or oral contraception-based treatment were also studied. For studies in vitro, Simpson Golabi Behmel Syndrome (SGBS) adipose cells were used. Gene expression for CXCL14 and other genes was quantified using quantitative real-time PCR. The levels of CXCL14 and adipokines in serum and cell culture media were determined by ELISA. RESULTS: Serum CXCL14 levels are reduced in patients with PCOS. One-year SPIOMET treatment normalized CXCL14 concentrations and improved the metabolic status of patients with PCOS. Pioglitazone induced CXCL14 expression in differentiating human SGBS adipocytes, in parallel with the induction of marker genes of brown adipogenesis. Spironolactone induced CXCL14 expression and release in differentiated human adipocytes. CONCLUSION: Insulin sensitization with SPIOMET normalizes the abnormally low levels of CXCL14 in girls with PCOS. This is consistent with the effects of pioglitazone and spironolactone inducing CXCL14 expression and promoting a brown-like phenotype in adipocytes. CXCL14 may be a novel biomarker for PCOS as well as a potential mediator of the beneficial effects of the SPIOMET combination and may hold promise as a therapeutic modulator of the disorder. TRIAL REGISTRATION NUMBERS: ISRCTN29234515 and ISCRCTN11062950.
Assuntos
Quimiocinas CXC/sangue , Hipoglicemiantes/administração & dosagem , Resistência à Insulina , Metformina/administração & dosagem , Antagonistas de Receptores de Mineralocorticoides/administração & dosagem , Pioglitazona/administração & dosagem , Síndrome do Ovário Policístico/sangue , Síndrome do Ovário Policístico/tratamento farmacológico , Espironolactona/administração & dosagem , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Adipogenia/genética , Tecido Adiposo Marrom/patologia , Adolescente , Arritmias Cardíacas/patologia , Biomarcadores/sangue , Quimiocinas CXC/genética , Anticoncepcionais Orais Hormonais/administração & dosagem , Quimioterapia Combinada , Etinilestradiol/administração & dosagem , Feminino , Expressão Gênica/efeitos dos fármacos , Doenças Genéticas Ligadas ao Cromossomo X/patologia , Gigantismo/patologia , Cardiopatias Congênitas/patologia , Humanos , Deficiência Intelectual/patologia , Levanogestrel/administração & dosagem , Resultado do TratamentoRESUMO
AQP7 is the primary glycerol transporter in white (WAT) and brown (BAT) adipose tissues. There are immediate and quantitatively important actions of cortisone over the expression of AQP7 in murine and human adipocytes. Short-term response (minutes) of cortisone treatment result in an mRNA overexpression in white and brown differentiated adipocytes (between 1.5 and 6 folds). Conversely, long-term response (hours or days) result in decreased mRNA expression. The effects observed on AQP7 mRNA expression upon cortisone treatment in brown and white differentiated adipocytes are concordant with those observed for GK and HSD1B11.
Assuntos
Tecido Adiposo , Aquaporinas , Glucocorticoides , Tecido Adiposo/metabolismo , Aquaporinas/genética , Aquaporinas/metabolismo , Regulação da Expressão Gênica , Glucocorticoides/metabolismo , Humanos , RNA Mensageiro/metabolismoRESUMO
Brown adipose tissue (BAT) is known to secrete regulatory factors in response to thermogenic stimuli. Components of the BAT secretome may exert local effects that contribute to BAT recruitment and activation. Here, we found that a thermogenic stimulus leads to enhanced secretion of kininogen (Kng) by BAT, owing to induction of kininogen 2 (Kng2) gene expression. Noradrenergic, cAMP-mediated signals induce KNG2 expression and release in brown adipocytes. Conversely, the expression of kinin receptors, that are activated by the Kng products bradykinin and [Des-Arg9]-bradykinin, are repressed by thermogenic activation of BAT in vivo and of brown adipocytes in vitro. Loss-of-function models for Kng (the circulating-Kng-deficient BN/Ka rat) and bradykinin (pharmacological inhibition of kinin receptors, kinin receptor-null mice) signaling were coincident in showing abnormal overactivation of BAT. Studies in vitro indicated that Kng and bradykinin exert repressive effects on brown adipocyte thermogenic activity by interfering the PKA/p38 MAPK pathway of control of Ucp1 gene transcription, whereas impaired kinin receptor expression enhances it. Our findings identify the kallikrein-kinin system as a relevant component of BAT thermogenic regulation that provides auto-regulatory inhibitory signaling to BAT.
Assuntos
Tecido Adiposo Marrom/metabolismo , Calicreínas/metabolismo , Cininas/metabolismo , Animais , Bradicinina/genética , Bradicinina/metabolismo , Sistema Endócrino/metabolismo , Imunofluorescência , Calicreínas/genética , Cininogênios/genética , Cininogênios/metabolismo , Cininas/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais/genética , Transdução de Sinais/fisiologiaRESUMO
OBJECTIVE: Transcriptomic analysis of gene expression in brown adipose tissue (BAT) from mice in response to cold revealed strong induction of growth and differentiation factor 15 (GDF15). This study aimed to characterize GDF15 as a brown adipokine released in response to thermogenic activation and to determine its target functions. METHODS: GDF15 expression was measured in adipose tissues from mice in response to physiological and pharmacological modulators of thermogenesis. Brown and beige cell cultures were used to dissect the mechanisms regulating GDF15 expression. Brown adipocyte cellular models of fibroblast growth factor 21 and ß-klotho invalidation were employed to identify the autocrine regulators of GDF15. RAW 264.7 macrophages were used to explore the targeting of GDF15 released by brown adipocytes. RESULTS: Cold exposure of mice strongly induced GDF15 expression in BAT. Norepinephrine and cyclic adenosine monophosphate induced GDF15 expression and release by cells through protein kinase A-mediated mechanisms. Noradrenergic regulation of GDF15 required the active fibroblast growth factor 21 pathway in brown adipocytes. GDF15 released by brown adipocytes targeted macrophages and downregulated the expression of proinflammatory genes. CONCLUSIONS: GDF15 is a brown adipokine released by brown and beige cells in response to thermogenic activity. GDF15 released by BAT targets macrophages and may mediate downregulation of local inflammatory pathways.
Assuntos
Adipócitos Marrons/metabolismo , Fator 15 de Diferenciação de Crescimento/metabolismo , Termogênese/fisiologia , Tecido Adiposo Marrom/metabolismo , Animais , Células Cultivadas , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Fatores de Crescimento de Fibroblastos/genética , Fatores de Crescimento de Fibroblastos/metabolismo , Fator 15 de Diferenciação de Crescimento/genética , Fator 15 de Diferenciação de Crescimento/farmacologia , Proteínas Klotho , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Masculino , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células RAW 264.7 , Via Secretória/efeitos dos fármacos , Via Secretória/genética , Termogênese/efeitos dos fármacosRESUMO
BACKGROUND AND PURPOSE: FGF21 has emerged as a therapeutic strategy for treating type 2 diabetes mellitus due to its antidiabetic effects, and this has led to the development of long-acting analogues of FGF21. However, these compounds have some limitations, including a need to be administered by s.c. injection and their prolonged pharmacodynamic effect compared with native FGF21, which might be responsible for their reported side effects. EXPERIMENTAL APPROACH: We have previously demonstrated that i.p. administration of haem-regulated eukaryotic translation initiation factor 2α kinase (HRI) activators increases hepatic and circulating levels of FGF21. In this study, we examined the effects of p.o. administration of a new HRI activator, EPB-53, on high-fat diet (HFD)-induced glucose intolerance, hepatic steatosis, and hypertriglyceridaemia, and compared them with those of metformin. KEY RESULTS: EPB-53 administration for the last 2 weeks, to mice fed a HFD for 10 weeks, reduced body weight gain, improved glucose intolerance, and prevented hepatic steatosis and hypertriglyceridaemia, whereas metformin only ameliorated glucose intolerance. Moreover, EPB-53, similar to the reported effects of FGF21, reduced lipogenesis in cultured human hepatocytes and in the liver of mice fed a HFD. Administration of EPB-53 to Fgf21-knockout mice had no effects, demonstrating that its efficacy is dependent on this hormone. CONCLUSIONS AND IMPLICATIONS: Overall, the findings of this study demonstrate that p.o. administration of HRI activators, by increasing FGF21, is a promising strategy for the treatment of type 2 diabetes mellitus and non-alcoholic fatty liver disease.
Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Fatores de Crescimento de Fibroblastos/metabolismo , Intolerância à Glucose/tratamento farmacológico , Hiperlipidemias/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Proteínas Serina-Treonina Quinases/metabolismo , eIF-2 Quinase/metabolismo , Administração Oral , Animais , Linhagem Celular , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/metabolismo , Dieta Hiperlipídica , Fatores de Crescimento de Fibroblastos/sangue , Intolerância à Glucose/sangue , Intolerância à Glucose/metabolismo , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Humanos , Hiperlipidemias/sangue , Hiperlipidemias/metabolismo , Hipoglicemiantes/farmacologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Hepatopatia Gordurosa não Alcoólica/prevenção & controle , Triglicerídeos/sangueRESUMO
The beneficial effects of brown adipose tissue (BAT) are attributed to its capacity to oxidize metabolites and produce heat, but recent data suggest that secretory properties of BAT may also be involved. Here, we identify the chemokine CXCL14 (C-X-C motif chemokine ligand-14) as a novel regulatory factor secreted by BAT in response to thermogenic activation. We found that the CXCL14 released by brown adipocytes recruited alternatively activated (M2) macrophages. Cxcl14-null mice exposed to cold showed impaired BAT activity and low recruitment of macrophages, mainly of the M2 phenotype, into BAT. CXCL14 promoted the browning of white fat and ameliorated glucose/insulin homeostasis in high-fat-diet-induced obese mice. Impairment of type 2 cytokine signaling, as seen in Stat6-null mice, blunts the action of CXCL14, promoting adipose tissue browning. We propose that active BAT is a source of CXCL14, which concertedly promotes adaptive thermogenesis via M2 macrophage recruitment, BAT activation, and the browning of white fat.