Blood DNA methylation marks discriminate Chagas cardiomyopathy disease clinical forms.

Chagas disease is a parasitic disease from South America, affecting around 7 million people worldwide. Decades after the infection, 30% of people develop chronic forms, including Chronic Chagas Cardiomyopathy (CCC), for which no treatment exists. Two stages characterized this form: the moderate form, characterized by a heart ejection fraction (EF) ≥ 0.4, and the severe form, associated to an EF < 0.4. We propose two sets of DNA methylation biomarkers which can predict in blood CCC occurrence, and CCC stage. This analysis, based on machine learning algorithms, makes predictions with more than 95% accuracy in a test cohort. Beyond their predictive capacity, these CpGs are located near genes involved in the immune response, the nervous system, ion transport or ATP synthesis, pathways known to be deregulated in CCCs. Among these genes, some are also differentially expressed in heart tissues. Interestingly, the CpGs of interest are tagged to genes mainly involved in nervous and ionic processes. Given the close link between methylation and gene expression, these lists of CpGs promise to be not only good biomarkers, but also good indicators of key elements in the development of this pathology.

Blood DNA methylation marks discriminate Chagas cardiomyopathy disease clinical forms

Chagas disease is a parasitic disease from South America, affecting around 7 million people worldwide. Decades after the infection, 30% of people develop chronic forms, including Chronic Chagas Cardiomyopathy (CCC), for which no treatment exists. Two stages characterized this form: the moderate form, characterized by a heart ejection fraction (EF) ≥ 0.4, and the severe form, associated to an EF < 0.4. We propose two sets of DNA methylation biomarkers which can predict in blood CCC occurrence, and CCC stage. This analysis, based on machine learning algorithms, makes predictions with more than 95% accuracy in a test cohort. Beyond their predictive capacity, these CpGs are located near genes involved in the immune response, the nervous system, ion transport or ATP synthesis, pathways known to be deregulated in CCCs. Among these genes, some are also differentially expressed in heart tissues. Interestingly, the CpGs of interest are tagged to genes mainly involved in nervous and ionic processes. Given the close link between methylation and gene expression, these lists of CpGs promise to be not only good biomarkers, but also good indicators of key elements in the development of this pathology.

FAS gene polymorphisms (rs3740286 and rs4064) were not associated with pre-eclampsia risk.

Pre-eclampsia results in real risk and significant impact on indicators related to maternal and child health. The only known treatment is delivery of the fetus and placenta. Despite intensive research, the causes of PE remain to be elucidated. It is suggested that pre-eclampsia is caused by a global maternal inflammatory response to a damaged placenta. Besides inflammation, cytotoxic and apoptotic mechanisms are also implicated in the pathogenesis of pre-eclampsia. Considering the importance of apoptosis to pre-eclampsia genesis, the aim of this study was to determine the frequencies of the genotypes for FAS gene polymorphisms (rs3740286 and rs4064) and to associate these with pre-eclampsia development. Women with and without pre-eclampsia were investigated. Accordingly, peripheral blood was collected, and DNA extracted, followed by genotyping using Real-time PCR with hydrolysis probe. The results showed no association between genotypes and pre-eclampsia development for both polymorphisms studied (χ2=3.39; p=.177, for rs3740286 and χ2=0.119; p=.94 for rs4064). Women with familiar history of pre-eclampsia and primiparity showed more probability to develop the condition, by multiple logistic regression analysis (OR=8.61, CI=3.39-21.86, p<0.0001; OR=6.64. CI=2.94-14.99, p<0.0001, respectively). It seems that FAS gene polymorphisms (rs3740286 and rs4064) might not be important candidates for the development of pre-eclampsia.

Polymorphisms in the IL17A gene are not involved in the development of preeclampsia in the Brazilian population / Polimorfismos no gene IL17A não estão envolvidos no desenvolvimento de pré-eclâmpsia na população brasileira

ABSTRACT Introduction: Preeclampsia is defined by the development of hypertension associated with proteinuria after the 20th week of gestation in previously normotensive women. IL17A is a potent inducer of tissue inflammation and polymorphisms in the IL17A gene can modulate gene expression and affect the functioning of Th17 cells, strengthening susceptibility to preeclampsia. Objective: To investigate the polymorphisms rs4711998 A>G, rs8193036 C>T and rs2275913 A>G in the IL17A gene in women with preeclampsia. Methods: This is a control case study, composed of 263 women, 89 with preeclampsia and 174 of the control group. The polymorphisms investigated by real time polymerase chain reaction (PCR) allele discrimination technique. The risk of IL17A polymorphisms contributing to preeclampsia was assessed by the inheritance model through logistic regression. Statistical power presented 99.5% for association detection. Statistical significance was defined as p < 0.05. Results: Genotype frequencies as well as multiple logistic regression analysis were not statistically significant for the rs4711998 A>G, rs8193036 C>T and rs2275913 A>G polymorphisms of the IL17A gene. No association was found between any haplotypes of the polymorphisms investigated and the risk of developing PE. Conclusion: There is no association between the allele frequencies, genotype, inheritance models and haplotypes of the rs4711998 A>G, rs8193036 C>T and rs2275913 A>G polymorphisms of the IL17A gene and PE.

RESUMEN Introducción: La preeclampsia (PE) se define como hipertensión arterial asociada a proteinuria después de la semana 20 de gestación en mujeres anteriormente normotensas. La interleucina 17ª (IL17A) es un inductor potente de inflamación tisular y polimorfismos del gen IL17A pueden modular la expresión génica y afectar las funciones de las células Th17, aumentando la susceptibilidad a la PE. Objetivo: Investigar los polimorfismos rs4711998 A>G, rs8193036 C>T y rs2275913 A>G del gen IL17A en pacientes con PE. Métodos: Se realizó un estudio de casos y controles, compuesto por 263 mujeres: 89 diagnosticadas con PE y 174 del grupo de control. Se evaluaron los polimorfismos investigados a partir del ácido desoxirribonucleico (ADN) genómico aislado de la sangre periférica por reacción en cadena de la polimerasa (PCR) en tiempo real para discriminación alélica. El riesgo de los polimorfismos del gen IL17A para la PE fue evaluado según el modelo de herencia empleando regresión logística. El poder estadístico presentó 99,5% para la detección de asociación. Resultados: Las frecuencias genotípicas, así como el análisis de regresión logística múltiple, no fueron estadísticamente significativas para los polimorfismos rs3761549 C>T, rs3761548 A>C y rs2232365 A>G del gen IL17A. Ningún haplotipo de los polimorfismos investigados mostró asociación con el riesgo de desarrollo de PE. Conclusión: No hay asociación entre las frecuencias alélicas y genotípicas, los modelos de herencia y los haplotipos de los polimorfismos rs4711998 A>G, rs8193036 C>T y rs2275913 A>G del gen IL17A y la PE.

RESUMO Introdução: A pré-eclâmpsia (PE) é definida pelo desenvolvimento de hipertensão arterial associada à proteinúria após a semana de gestação em mulheres previamente normotensas. A interleucina 17A (IL17A) é um potente indutor de inflamação tecidual, e polimorfismos no gene IL17A podem modular a expressão gênica e afetar o funcionamento das células Th17, contribuindo para a suscetibilidade à PE. Objetivo: Investigar os polimorfismos rs4711998 A>G, rs8193036 C>T e rs2275913 A>G no gene IL17A em mulheres com PE. Métodos: Trata-se de um estudo do tipo caso-controle, composto por 263 mulheres, sendo 89 diagnosticadas com PE e 174 do grupo-controle. Os polimorfismos investigados foram avaliados a partir do ácido desoxirribonucleico (DNA) genômico extraído do sangue periférico pela técnica de discriminação alélica por reação em cadeia da polimerase (PCR) em tempo real. O risco de os polimorfismos do gene IL17A contribuírem com a PE foi avaliado pelo modelo de herança através da regressão logística. O poder estatístico apresentou 99,5% para a detecção de associação. A significância estatística foi definida como p < 0,05. Resultados: As frequências genotípicas, assim como a análise de regressão logística múltipla, não foram estatisticamente significativas para os polimorfismos rs3761549 C>T, rs3761548 A>C e rs2232365 A>G do gene IL17A. Não foi observada associação entre nenhum dos haplótipos dos polimorfismos investigados e o risco de desenvolvimento de PE. Conclusão: Não há associação entre as frequências alélicas e genotípicas, os modelos de herança e os haplótipos dos polimorfismos rs4711998 A>G, rs8193036 C>T e rs2275913 A>G do gene IL17A e a PE.

Polymorphic sites at the immunoregulatory CTLA-4 gene are associated with chronic chagas disease and its clinical manifestations.

BACKGROUND: Chagas disease affects approximately 10 million people mainly in Latin America. The immune regulation by the host seems to be an essential factor for disease evolution, and immune system inhibitory molecules such as CTLA-4 and PD-1 favor the maintenance of peripheral tolerance. Considering that polymorphisms at the immunoregulatory CTLA-4 and PDCD1 genes may alter their inhibitory function, we investigated the association of alleles, genotypes and haplotypes of polymorphic sites observed at the CTLA-4 and PDCD1 genes with different clinical manifestations of chronic Chagas disease (indeterminate, cardiac, digestive and mixed). METHODS: The polymorphisms at the CTLA-4 (-1722T/C, -318C/T and +49A/G) and PDCD1 (PD-1.3G/A) genes were typed using TaqMan methodology in 277 chronic Chagas disease patients classified into four groups, according to clinical characteristics, and 326 non-infected controls. RESULTS: Our results showed that CTLA-4 -1722CC genotype (22%), -1722C allele (27%) and CTLA-4 TCG (8.6%), TCA (26%) and CCA (15%) haplotypes were strongly associated with the indeterminate form, while the CTLA-4-318CT genotype (82%) and CTLA-4-318T allele (47%) were found mainly in patients with the mixed form of the disease. The CTLA-4 TCG haplotype (10.2%) was associated with the digestive form. On the other hand, the PD-1.3G/A polymorphism was not associated with chronic Chagas disease and its clinical manifestations. CONCLUSIONS: Here, we showed that alleles, genotypes and haplotypes reported to increase the expression of the regulatory molecule CTLA-4 were associated with the indeterminate form of the disease. Taken together, our data support the idea that polymorphic sites at immunoregulatory genes may influence the development of Chagas disease variants.