Influence of polymorphisms in IRS1, IRS2, MC3R, and MC4R on metabolic and inflammatory status and food intake in Brazilian adults: An exploratory pilot study.

Polymorphisms in genes of leptin-melanocortin and insulin pathways have been associated with obesity and type 2 diabetes. We hypothesized that polymorphisms in IRS1, IRS2, MC3R, and MC4R influence metabolic and inflammatory markers and food intake composition in Brazilian subjects. This exploratory pilot study included 358 adult subjects. Clinical, anthropometric, and laboratory data were obtained through interview and access to medical records. The variants IRS1 rs2943634 A˃C, IRS2 rs1865434 C>T, MC3R rs3746619 C>A, and MC4R rs17782313 T>C were analyzed by real-time polymerase chain reaction. Food intake composition was assessed in a group of subjects with obesity (n = 84) before and after a short-term nutritional counseling program (9 weeks). MC4R rs17782313 was associated with increased risk of obesity (P = .034). Multivariate linear regression analysis adjusted by covariates indicated associations of IRS2 rs1865434 with reduced low-density lipoprotein cholesterol and resistin, MC3R rs3746619 with high glycated hemoglobin, and IRS1 rs2943634 and MC4R rs17782313 with increased high-sensitivity C-reactive protein (P < .05). Energy intake and carbohydrate and total fat intakes were reduced after the diet-oriented program (P < .05). Multivariate linear regression analysis showed associations of IRS2 rs1865434 with high basal fiber intake, IRS1 rs2943634 with low postprogram carbohydrate intake, and MC4R rs17782313 with low postprogram total fat and saturated fatty acid intakes (P < .05). Although significant associations did not survive correction for multiple comparisons using the Benjamini-Hochberg method in this exploratory study, polymorphisms in IRS1, IRS2, MC3R, and MC4R influence metabolic and inflammatory status in Brazilian adults. IRS1 and MC4R variants may influence carbohydrate, total fat, and saturated fatty acid intakes in response to a diet-oriented program in subjects with obesity.

Peripheral Blood miRome Identified miR-155 as Potential Biomarker of MetS and Cardiometabolic Risk in Obese Patients.

This study explored circulating miRNAs and target genes associated with metabolic syndrome (MetS) and cardiometabolic risk in obese patients. Small-RNA sequencing was used to assess the peripheral blood miRNome of 12 obese subjects (6 MetS and 6 non-MetS). Differentially expressed miRNAs and target genes were further analyzed by qPCR in a larger sample of obese patients (48 MetS and 32 non-MetS). miRNA:mRNA interactions were studied using in silico tools. miRNome analysis identified 10 downregulated miRNAs in MetS compared to non-Met patients (p < 0.05). In silico studies revealed three miRNAs (miR-155, miR-181a, and let-7a) and their predictive targets (CCAAT/enhancer-binding protein beta-CEBPB, KRAS proto-oncogene, GTPase-KRAS and suppressor of cytokine signaling 1-SOCS1) with a potential role in the insulin receptor signaling pathway. miR-155 expression was reduced and CEBPB mRNA levels were increased in MetS patients (p < 0.05), and these effects were correlated with the number of MetS diagnostic criteria (p < 0.05). Increased HOMA-IR (>7.6) was associated with low miR-155 levels, high CEBPB expression, and serum hsCRP (p < 0.05). miR-155 was negatively correlated with CEBPB, HOMA-IR, and plasma fibrinogen, and positively correlated with serum adiponectin (p < 0.05). Downregulation of circulating miR-155 is associated with insulin resistance, poor glycemic control, and increased MetS-related cardiometabolic risk, and these effects are potentially mediated by interaction with CEBPB.

Análise de miRNoma em sangue periférico de indivíduos com obesidade e resistência à insulina / Analysis of miRNA in peripheral blood of the individual with obesity and insulin resistance

INTRODUÇÃO: A obesidade é uma doença multifatorial associada com alto risco de desenvolver resistência à insulina (RI), diabetes melito tipo 2 (DT2), síndrome metabólica (SM) e doenças cardiovasculares (DCV). Os mecanismos moleculares da fisiopatologia das doenças metabólicas não são totalmente compreendidos, emergindo a necessidade de novas estratégias. As modificações epigenéticas, especialmente os miRNAs, podem representar uma importante ferramenta, uma vez que são relacionados com o desenvolvimento de diversas doenças complexas, como as metabólicas. OBJETIVO: Avaliar o perfil de expressão de miRNAs séricos de indivíduos com obesidade, síndrome metabólica e resistência à insulina e sua relação com os mecanismos moleculares envolvidos nas suas fisiopatologias. CASUÍSTICA E MÉTODOS: O estudo foi realizado no Instituto Dante Pazzanese de Cardiologia (IDPC) e no Hospital Universitário da Universidade de São Paulo (HU/USP). Um total de 233 indivíduos foram distribuídos em três grupos: peso normal (n=47), sobrepeso (84) e obesos (102), de acordo com seu índice de massa corpórea (IMC). Os mesmos pacientes também foram re-classificados em com SM (n=89) e sem SM (n=144) de acordo com recomendações da Federação internacional de Diabetes e em com RI (n=123) e sem RI (n=110). As informações biodemográficas e amostras de sangue foram coletadas para testes laboratoriais clínicos e análises de perfis de expressão de miRNA pela PCR array (372 alvos). Analises in silico com a ferramenta Ingenuity Pathway Analysis (IPA) foi realizada para integração do perfil de miRNAs e seus genes alvos com doenças metabólicas. RESULTADOS: Os pacientes obesos e com RI, apresentaram aumento similar das concentrações de marcadores dos perfis lipídico, glicídico e inflamatório quando comparado com indivíduos com peso normal e sem RI. O perfil de miRNAs dos grupos obesos e com RI mostrou que o miR-346 (p=0,010; p=0,019), 483-5p (p=0,034; p=0,020), 296-3p (p=0,010; p=0,008), 1224-3p (p=0,044; p=0,012) e 95-3p (p=0,003; p=0,019) foram expressos similarmente nestes pacientes quando comparados a seus respectivos controles. Estes miRNAs, por predição in silico, desempenham um importante papel na regulação de vias metabólicas associadas a doenças hepáticas gordurosas, inflamação, DCV e doenças metabólicas. Na SM, o grupo portador da doença apresentou altas concentrações de marcadores do perfil lipídico, glicídico e inflamatório. O perfil de expressão de miRNA indicou uma expressão reduzida do miR-183-5p (p=0,008) e miR-301a-3p (p=0,007) e aumentada do miR-542-5p (p=0,003), miR-424-3p (p=0,040), miR-326 (p=0,037), miR-421 (p=0,023) e miR-574-3p (p=0,001) no grupo SM comparado ao sem SM. A análise de regressão linear múltipla stepwise indicou que a expressão aumentada do miR-421 explica em 22,5% o aumento da associação de Hb1Ac, LDL-C, PAI-1, HOMA-IR, glicose e insulina (p <0,001, p=0,014, p=0,009, p <0,001, p=0,001 e p=0,007, respectivamente). Além disso o miR-421 foi predito in silico estar associado com a regulação de 11 mRNA alvos envolvidos em vias regulatórias de doenças como infarto do miocárdio, obesidade, diabetes melito, esteatose hepática, tolerância a glicose, distúrbio do metabolismo da glicose, hiperglicemia e resistência à insulina, bem como atua em vias regulatórias da resposta inflamatória, sendo associado com a variabilidade na quantidade de citocinas, massa do tecido adiposo e quantidade de leptina no sangue. Mediante a relação do miR-421 com a homeostase da glicose, sua expressão foi testada em pacientes com RI e interessantemente se manteve aumentada nesses pacientes em comparação com os sem RI (p=0.014). CONCLUSÕES: Os miR-346, miR-483-5p, miR-296-3p, miR-1224-3p e miR-95-3p podem ser considerados potenciais biomarcadores como preditores de DCV em pacientes obesos e resistência à insulina e o miR-421 um potencial biomarcador precoce de predição de risco de DCV em pacientes com síndrome metabólica

BACKGROUND: Obesity is a multifactorial disease associated with high risk of developing insulin resistance (IR), Diabetes mellitus type 2 (DT2), metabolic syndrome (MetS) and cardiovascular disease (CVD). Molecular mechanisms of metabolic diseases' pathophysiology are not fully understood, emerging the need for new strategies. Epigenetic modifications, especially miRNAs, may represent an important tool, since they are related to the development of several complex diseases, such as those metabolic. OBJECTIVE: Evaluate miRNA-derived serum expression profile in individuals with obesity, MetS and IR and their relationship with molecular mechanisms involved in the metabolic disease pathophysiology. MATERIAL AND METHODS: The study was conducted at the Dante Pazzanese Institute of Cardiology (IDPC) and at University Hospital of the University of São Paulo (HU/USP). Two hundred thirty-three subjects were distributed into three groups: normal weight (n = 47), overweight (n=84) and obese (n=102), according to their body mass index (BMI). The same patients were also re-classified as MetS (n=89) and Non-MetS (n=144) according to recommendations of the International Diabetes Federation and in IR (n=123) and Non-IR. Biodemographic data were registered and blood samples were collected for clinical laboratory tests and miRNA expression profiles by PCR array (372 targets). In silico analysis using Ingenuity Pathway Analysis (IPA) tool was performed to integrate the miRNA profile and their target genes with metabolic diseases. RESULTS: Obese and IR patients had similar increases in the concentrations of lipid, glucose and inflammatory markers when compared to individuals with normal weight and without IR, respectively. miRNA profile of obese and IR groups showed that miR-346 (p = 0.010, p = 0.019), 483-5p (p = 0.034, p = 0.020), 296-3p (p = 0.010, p = 0.008), 1224-3p (p = 0.044, p = 0.012) and 95-3p (p = 0.003, p = 0.019) were similarly expressed in these patients in comparison to their respective controls. These miRNAs, by in silico prediction, play an important role in the regulation of metabolic pathways associated with fatty liver diseases, inflammation, CVD and metabolic diseases. In MetS, patients diagnosed with the disease showed high concentrations of lipid, glycogen and inflammatory markers. The miRNA expression profile indicated a reduced expression of miR-183-5p (p=0.008) and miR-301a-3p (p=0.007) and increased miR-542-5p (p=0.003), miR- 3 (p=0.040), miR-326 (p=0.037), miR-421 (p=0.023) and miR-574-3p (p=0.001) in the MetS group compared to Non-MetS. Stepwise multiple linear regression analysis indicated that increased expression of miR-421 explain in 22.5% increased of Hb1Ac, LDL-C, PAI-1, HOMA-IR, glucose and insulin (p<0.001, p=0.014, p=0.009, p<0.001, p=0.001 and p=0.007, respectively). In addition the miR-421 was predicted in silico to associated with regulation of eleven mRNA of gene targets involved in regulatory pathways of diseases such as myocardial infarction, obesity, diabetes mellitus, hepatic steatosis, glucose tolerance, glucose metabolism disorder, hyperglycemia and insulin resistance, as well inflammatory response and is also associated with variability in the amount of cytokines, adipose tissue mass and amount of leptin in the blood. Due the relationship of miR-421 with glucose homeostasis, the miRNA expression was tested in patients with IR. Interestingly, miR-421 remained increased in these patients compared to those without IR (p = 0.014). CONCLUSIONS: The miR-346, miR-483-5p, miR-296-3p, miR-1224-3p and miR-95-3p may be potential biomarkers to predict CVD in obese and IR patients, while the miR-421 is a potential biomarker to predict CVD in MetS patients