RESUMO
T1D can be associated with metabolic disorders and several impaired pathways, including insulin signaling, and development of insulin resistance through the renin-angiotensin system (RAS). The main precursor of RAS is angiotensinogen (Agt) and this system is often linked to autophagy dysregulation. Dysregulated autophagy has been described in T1D and linked to impairments in both glucose metabolism, and leukotrienes (LTs) production. Here, we have investigated the role of RAS and LTs in both muscle and liver from T1D mice, and its effects on insulin and autophagy pathways. We have chemically induced T1D in 129sve and 129sve 5LO-/- mice (lacking LTs) with streptozotocin (STZ). To further inhibit ACE activity, mice were treated with captopril (Cap). In muscle of T1D mice, treatment with Cap increased the expression of RAS (angiotensinogen and angiotensin II receptor), insulin signaling, and autophagy markers, regardless of the genotype. In the liver of T1D mice, the treatment with Cap increased the expression of RAS and insulin signaling markers, mostly when LTs were absent. 5LO-/- T1D mice showed increased insulin sensitivity, and decreased NEFA, after the Cap treatment. Cap treatment impacted both insulin signaling and autophagy pathways at the mRNA levels in muscle and liver, indicating the potential role of ACE inhibition on insulin sensitivity and autophagy in T1D.
Assuntos
Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 1 , Resistência à Insulina , Camundongos , Animais , Captopril/farmacologia , Angiotensinogênio/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Experimental/metabolismo , Sistema Renina-Angiotensina , Insulina/metabolismo , Leucotrienos/metabolismoRESUMO
This study aims to investigate the global profiling of genes and miRNAs expression to explore the regulatory effects of eicosapentaenoic acid (EPA) in visceral adipose tissue (VAT) of obese mice. We used male mice, fed either a high-fat diet (HF) or HF supplemented with EPA (HF-EPA), for 11 weeks. RNA, and small RNA profiling, were performed by RNAseq analysis. We conducted analyses using Ingenuity Pathway Analysis software (IPA®) and validated candidate genes and miRNAs related to lipid mediators and inflammatory pathways using qRT-PCR. We identified 153 genes differentially downregulated, and 62 microRNAs differentially expressed in VAT from HF-EPA compared to HF. Genes with a positive association with inflammation, chemotaxis, insulin resistance, and inflammatory cell death, such as Irf5, Alox5ap, Tlrs, Cd84, Ccr5, Ccl9, and Casp1, were downregulated by EPA. Moreover, EPA significantly reduced LTB4 levels, a lipid mediator with a central role in inflammation and insulin resistance in obesity. The pathways and mRNA/microRNA interactions identified in our study corroborated with data validated for inflammatory genes and miRNAs. Together, our results identified key VAT inflammatory targets and pathways, which are regulated by EPA. These targets merit further investigation to better understand the protective mechanisms of EPA in obesity-associated inflammation.
Assuntos
Anti-Inflamatórios/farmacologia , Ácido Eicosapentaenoico/farmacologia , Gordura Intra-Abdominal/metabolismo , Animais , Anti-Inflamatórios/uso terapêutico , Dieta Hiperlipídica/efeitos adversos , Ácido Eicosapentaenoico/uso terapêutico , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Redes Reguladoras de Genes/efeitos dos fármacos , Inflamação/metabolismo , Gordura Intra-Abdominal/efeitos dos fármacos , Leucotrieno B4/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Obesos , MicroRNAs/metabolismo , Obesidade/induzido quimicamente , Obesidade/genética , Obesidade/metabolismo , Receptores de Superfície Celular/efeitos dos fármacos , Receptores de Superfície Celular/genética , Transdução de Sinais/efeitos dos fármacos , Transcrição Gênica/efeitos dos fármacos , TranscriptomaRESUMO
Serum levels of leukotriene-B4 (LTB4) are increased in type 1 diabetes (T1D) and it mediates systemic inflammation and macrophage reprogramming associated with this condition. Herein, we investigated the involvement of LTB4 in adiposity loss, hyperlipidemia, and changes in macrophage metabolism in a mouse model of streptozotocin-induced T1D. LTB4 receptor (BLT1) antagonist u75302 was employed to block LTB4 effects. As expected, hypoinsulinemia in T1D was associated with hyperglycemia, low levels of glucagon, hyperlipidemia, significant body fat loss, and increased white adipose tissue expression of Fgf21, a marker for lipolysis. With the exception of hyperglycemia and hypoglucagonemia, blockade of LTB4 signaling reverted these parameters in T1D mice. Along with hyperlipidemia, macrophages from T1D mice exhibited higher lipid uptake and accumulation. These cells also had enhanced glycolysis and oxidative metabolism and these parameters were dependent on the mitochondrial uncoupling respiration, as evidenced by elevated expression of oxidation markers carnitine palmitoyltransferase and uncoupling protein 1. Interestingly, all these parameters were at least partially reverted in T1D mice treated with u75302. Altogether, these findings suggest that in T1D mice LTB4/BLT1 is involved in the fat loss, hyperlipidemia, and increased macrophage lipid uptake and metabolism with an important involvement of mitochondrial uncoupling activity. These previously unrecognized LTB4/BLT1 functions may be explored in future to therapeutically alleviate severity of hyperlipidemia and systemic inflammation in T1D.
Assuntos
Adiposidade , Diabetes Mellitus Tipo 1/metabolismo , Leucotrieno B4/farmacologia , Macrófagos Peritoneais/metabolismo , Adiposidade/efeitos dos fármacos , Animais , Biomarcadores/metabolismo , Regulação para Baixo/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Ácidos Graxos/metabolismo , Glicólise/efeitos dos fármacos , Hiperlipidemias/metabolismo , Hiperlipidemias/patologia , Lipogênese/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Macrófagos Peritoneais/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Oxirredução/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Proteína Desacopladora 1/metabolismoRESUMO
SCOPE: The mechanisms and involvement of uncoupling protein 1 (UCP1) in the protection from obesity and insulin resistance induced by intake of a high-fat diet rich in omega-3 (n-3) fatty acids are investigated. METHODS AND RESULTS: C57BL/6J mice are fed either a low-fat (control group) or one of two isocaloric high-fat diets containing either lard (HFD) or fish oil (HFN3) as fat source and evaluated for body weight, adiposity, energy expenditure, glucose homeostasis, and inguinal white and interscapular brown adipose tissue (iWAT and iBAT, respectively) gene expression, lipidome, and mitochondrial bioenergetics. HFN3 intake protected from obesity, glucose and insulin intolerances, and hyperinsulinemia. This is associated with increased energy expenditure, iWAT UCP1 expression, and incorporation of n-3 eicosapentaenoic and docosahexaenoic fatty acids in iWAT and iBAT triacylglycerol. Importantly, HFN3 is equally effective in reducing body weight gain, adiposity, and glucose intolerance and increasing energy expenditure in wild-type and UCP1-deficient mice without recruiting other thermogenic processes in iWAT and iBAT, such as mitochondrial uncoupling and SERCA-mediated calcium and creatine-driven substrate cyclings. CONCLUSION: Intake of a high-fat diet rich in omega-3 fatty acids protects both wild-type and UCP1-deficient mice from obesity and insulin resistance by increasing energy expenditure through unknown mechanisms.