Integrated bioinformatics approach reveals methylation-regulated differentially expressed genes in obesity

ABSTRACT Objective: To identify DNA methylation and gene expression profiles involved in obesity by implementing an integrated bioinformatics approach. Materials and methods: Gene expression (GSE94752, GSE55200, and GSE48964) and DNA methylation (GSE67024 and GSE111632) datasets were obtained from the GEO database. Differentially expressed genes (DEGs) and differentially methylated genes (DMGs) in subcutaneous adipose tissue of patients with obesity were identified using GEO2R. Methylation-regulated DEGs (MeDEGs) were identified by overlapping DEGs and DMGs. The protein-protein interaction (PPI) network was constructed with the STRING database and analyzed using Cytoscape. Functional modules and hub-bottleneck genes were identified by using MCODE and CytoHubba plugins. Functional enrichment analyses were performed based on Gene Ontology terms and KEGG pathways. To prioritize and identify candidate genes for obesity, MeDEGs were compared with obesity-related genes available at the DisGeNET database. Results: A total of 54 MeDEGs were identified after overlapping the lists of significant 274 DEGs and 11,556 DMGs. Of these, 25 were hypermethylated-low expression genes and 29 were hypomethylated-high expression genes. The PPI network showed three hub-bottleneck genes (PTGS2, TNFAIP3, and FBXL20) and one functional module. The 54 MeDEGs were mainly involved in the regulation of fibroblast growth factor production, the molecular function of arachidonic acid, and ubiquitin-protein transferase activity. Data collected from DisGeNET showed that 11 of the 54 MeDEGs were involved in obesity. Conclusion: This study identifies new MeDEGs involved in obesity and assessed their related pathways and functions. These results data may provide a deeper understanding of methylation-mediated regulatory mechanisms of obesity.

Polymorphisms in TIE2 and ANGPT-1 genes are associated with protection against diabetic retinopathy in a Brazilian population

ABSTRACT Objective: The objective of this study was to investigate the association between SNPs in the TIE2 and ANGPT-1 genes and diabetic retinopathy (DR). Subjects and methods: This study comprised 603 patients with type 2 diabetes mellitus (T2DM) and DR (cases) and 388 patients with T2DM for more than 10 years and without DR (controls). The TIE2 rs639225 (A/G) and rs638203 (A/G) SNPs and the ANGPT-1 rs4324901 (G/T) and rs2507800 (T/A) SNPs were genotyped by real-time PCR using TaqMan MGB probes. Results: The G/G genotype of the rs639225/TIE2, the G/G genotype of the rs638203/TIE2 and the T allele of the rs4324901/ANGPT-1 SNPs were associated with protection against DR after adjustment for age, glycated hemoglobin, gender, and presence of hypertension (P = 0.042, P = 0.003, and P = 0.028, respectively). No association was found between the rs2507800/ANGPT-1 SNP and DR. Conclusion: We demonstrated, for the first time, the association of TIE2 rs638203 and rsrs939225 SNPs and ANGPT-1 rs4324901 SNP with protection against DR in a Brazilian population.

Estimuladores de Guanilato Ciclase Solúvel (Riociguate) na Hipertensão Pulmonar: Dados da Prática Clínica Real em 3 Anos de Acompanhamento / Soluble Guanylate Cyclase Stimulators (Riociguat) in Pulmonary Hypertension: Data from Real-Life Clinical Practice in a 3-Year Follow-Up

Resumo Fundamento A hipertensão pulmonar (HP) é uma doença rara e complexa com prognóstico ruim, que exige tratamento pela vida toda. Objetivo Descrever dados de 3 anos de acompanhamento da vida real sobre o tratamento com estimuladores de guanilato ciclase solúvel (Riociguate) de pacientes com HP, medindo parâmetros atuais de avaliação de risco. Métodos Coletamos dados clínicos e epidemiológicos retrospectivamente de pacientes com HP do grupo 1 (hipertensão arterial pulmonar) e do grupo 4 (HP tromboembólica crônica). Parâmetros não invasivos e invasivos correspondentes à avaliação de risco foram analisados na linha de base e no acompanhamento. Foram realizadas análises estatísticas usando o software SPSS 18.0, e os p-valores <0,050 foram considerados estatisticamente significativos. Resultados No total, 41 pacientes tratados com riociguate foram incluídos no estudo. Entre eles, 31 já concluíram 3 anos de tratamento e foram selecionados para a seguinte análise. Na linha de base, 70,7% dos pacientes estavam nas classes funcionais III ou IV da OMS. Depois de 3 anos de tratamento, a classe funcional da OMS melhorou significativamente em todos os pacientes. Além disso, a mediana do teste de caminhada de 6 minutos (TC6M) aumentou significativamente de 394 ± 91 m na linha de base para 458 ± 100 m após 3 anos de acompanhamento (p= 0,014). O índice de sobrevida após três anos foi de 96,7%. Conclusão Em nossa coorte de vida real, a maioria dos pacientes com HP tratados com riociguate demonstraram parâmetros de risco estáveis ou melhores, especialmente no TC6M, aos 3 anos de acompanhamento.

Abstract Background Pulmonary hypertension (PH) is a rare and complex disease with poor prognosis, which requires lifelong treatment. Objective To describe 3-year follow-up real-life data on treatment with soluble guanylate cyclase stimulators (Riociguat) of patients with PH, measuring current risk assessment parameters. Methods This study retrospectively collected clinical and epidemiological data of patients with PH of group 1 (pulmonary arterial hypertension) and group 4 (chronic thromboembolic PH). Non-invasive and invasive parameters corresponding to the risk assessment were analyzed at baseline and follow-up. Statistical analyses were performed using the SPSS 18.0 software, and p-values < 0.050 were considered statistically significant. Results In total, 41 patients receiving riociguat were included in the study. Of them, 31 had already completed 3 years of treatment and were selected for the following analysis. At baseline, 70.7% of patients were in WHO functional class III or IV. After 3 years of treatment, the WHO functional class significantly improved in all patients. In addition, the median of the 6-minute walk test (6MWT) significantly increased from 394 ± 91 m at baseline to 458 ± 100 m after 3 years of follow-up (p= 0.014). The three-year survival rate was 96.7%. Conclusion In our real-life cohort, most patients with PH treated with riociguat showed stable or improved risk parameters, especially in the 6MWT, at 3 years of follow-up.

The rs11755527 polymorphism in the BACH2 gene and type 1 diabetes mellitus: case control study in a Brazilian population

ABSTRACT Objective Type 1 diabetes mellitus (T1DM) is an autoimmune disorder caused by a complex interaction between environmental and genetic risk factors. BTB domain and CNC homolog 2 (BACH2) gene encodes a transcription factor that acts on the differentiation and formation of B and T lymphocytes. BACH2 is also involved in the suppression of apoptosis and inflammation in pancreatic beta-cells, indicating a role for it in the development of T1DM. Therefore, the aim of this study was to evaluate the association of the BACH2 rs11755527 single nucleotide polymorphism (SNP) with T1DM. Subjects and methods This case-control study comprised 475 patients with T1DM and 598 nondiabetic individuals. The BACH2 rs11755527 (C/G) SNP was genotyped using real-time PCR with TaqMan MGB probes. Results Genotype distributions of rs11755527 SNP were in accordance with frequencies predicted by the Hardy-Weinberg equilibrium in case and control groups and were similar between groups (P = 0.729). The minor allele frequency was 43.6% in cases and 42.5% in controls (P = 0.604). Moreover, the G allele frequency did not differ between groups when considering different inheritance models and adjusting for age, gender, body mass index, and HLA DR/DQ genotypes of high-risk for T1DM. Although, well-known high-risk T1DM HLA DR/DQ genotypes were associated with T1DM in our population [OR= 7.42 (95% CI 3.34 - 17.0)], this association was not influenced by the rs11755527 SNP. Conclusion The BACH2 rs11755527 SNP seems not to be associated with T1DM in a Brazilian population.

Toll-like receptor 3 (TLR3) and the development of type 1 diabetes mellitus

Type 1 diabetes mellitus (T1DM) is a chronic, progressive autoimmune disease characterized by metabolic decompensation often leading to dehydration and ketoacidosis. Viral agents seem to play an important role in triggering the autoimmune destruction that leads to the development of T1DM. Among several viral strains investigated so far, the enterovirus family has been consistently associated with the onset of T1DM in humans. One of the mediators of viral damage is the double-stranded RNA (dsRNA) generated during replication and transcription of viral RNA and DNA. The Toll-like receptor 3 (TLR3) gene codes for an endoplasmic receptor of the pattern-recognition receptors (PRRs) family that recognizes dsRNA, plays an important role in the innate immune response triggered by viral infection. Binding of dsRNA to the TLR3 triggers the release of proinflammatory cytokines, such as interferons, which exhibit potent antiviral action; thus, protecting uninfected cells and inducing apoptosis of infected ones. Therefore, the TLR3 gene is a good candidate for the development of T1DM. Within this context, the objective of the present review was to address the role of the TLR3 gene in the development of T1DM. Arch Endocrinol Metab. 2015;59(1):4-12.

The role of the uncoupling protein 1 (UCP1) on the development of obesity and type 2 diabetes mellitus / Papel da proteína desacopladora 1 (UCP1) no desenvolvimento da obesidade e do diabetes melito tipo 2

It is well established that genetic factors play an important role in the development of both type 2 diabetes mellitus (DM2) and obesity, and that genetically susceptible subjects can develop these metabolic diseases after being exposed to environmental risk factors. Therefore, great efforts have been made to identify genes associated with DM2 and/or obesity. Uncoupling protein 1 (UCP1) is mainly expressed in brown adipose tissue, and acts in thermogenesis, regulation of energy expenditure, and protection against oxidative stress. All these mechanisms are associated with the pathogenesis of DM2 and obesity. Hence, UCP1 is a candidate gene for the development of these disorders. Indeed, several studies have reported that polymorphisms -3826A/G, -1766A/G and -112A/C in the promoter region, Ala64Thr in exon 2 and Met299Leu in exon 5 of UCP1 gene are possibly associated with obesity and/or DM2. However, results are still controversial in different populations. Thus, the aim of this study was to review the role of UCP1 in the development of these metabolic diseases.

Está bem estabelecido que fatores genéticos têm papel importante no desenvolvimento do diabetes melito tipo 2 (DM2) e obesidade e que indivíduos suscetíveis geneticamente podem desenvolver essas doenças metabólicas após exposição a fatores de risco ambientais. Assim, grandes esforços têm sido feitos para a identificação de genes associados ao DM2 e/ou à obesidade. A proteína desacopladora 1 (UCP1) é principalmente expressa no tecido adiposo marrom e atua na termogênese, regulação do gasto energético e proteção contra o estresse oxidativo, mecanismos associados tanto à patogênese do DM2 como à obesidade. Portanto, UCP1 é um gene candidato para o desenvolvimento dessas doenças. De fato, diversos estudos relataram que os polimorfismos -3826A/G, -1766A/G e -112A/C na região promotora, Ala64Thr no éxon 2 e Met299Leu no éxon 5 do gene UCP1 estão possivelmente associados à obesidade e/ou ao DM2. Entretanto, os resultados são ainda controversos em diferentes populações. Então, o objetivo deste estudo foi revisar o papel da UCP1 no desenvolvimento dessas doenças metabólicas.

The role of uncoupling protein 2 (UCP2) on the development of type 2 diabetes mellitus and its chronic complications / Papel da proteína desacopladora 2 (UCP2) no desenvolvimento do diabetes melito tipo 2 e de suas complicações crônicas

It is well established that genetic factors play an important role in the development of type 2 diabetes mellitus (DM2) and its chronic complications, and that genetically susceptible subjects can develop the disease after being exposed to environmental risk factors. Therefore, great efforts have been made to identify genes associated with DM2. Uncoupling protein 2 (UCP2) is expressed in several tissues, and acts in the protection against oxidative stress; in the negative regulation of insulin secretion by beta cells, and in fatty acid metabolism. All these mechanisms are associated with DM2 pathogenesis and its chronic complications. Therefore, UCP2 is a candidate gene for the development of these disorders. Indeed, several studies have reported that three common polymorphisms in UCP2 gene are possibly associated with DM2 and/or obesity. Only a few studies investigated these polymorphisms in relation to chronic complications of diabetes, with inconclusive results.

Está bem estabelecido que fatores genéticos têm papel importante no desenvolvimento do diabetes melito tipo 2 (DM2) bem como de suas complicações crônicas e que indivíduos geneticamente suscetíveis podem desenvolver essa doença após exposição a fatores de risco ambientais. Assim, grandes esforços têm sido feitos para a identificação de genes associados ao DM2. A proteína desacopladora 2 (UCP2) é expressa em diversos tecidos e atua na proteção contra o estresse oxidativo, na regulação negativa da secreção de insulina pelas células-beta e no metabolismo dos ácidos graxos, mecanismos associados tanto à patogênese do DM2 como a suas complicações crônicas. Portanto, o gene UCP2 é um gene candidato para o desenvolvimento dessas doenças. De fato, diversos estudos têm relatado que três polimorfismos comuns no gene UCP2 estão possivelmente associados ao DM2 e/ou à obesidade. Apenas poucos estudos investigaram esses polimorfismos em relação às complicações crônicas do diabetes, obtendo resultados pouco conclusivos.