Epigenetic regulation by hypoxia, N-acetylcysteine and hydrogen sulphide of the fetal vasculature in growth restricted offspring: A study in humans and chicken embryos.

Fetal growth restriction (FGR) is a common outcome in human suboptimal gestation and is related to prenatal origins of cardiovascular dysfunction in offspring. Despite this, therapy of human translational potential has not been identified. Using human umbilical and placental vessels and the chicken embryo model, we combined cellular, molecular, and functional studies to determine whether N-acetylcysteine (NAC) and hydrogen sulphide (H2S) protect cardiovascular function in growth-restricted unborn offspring. In human umbilical and placental arteries from control or FGR pregnancy and in vessels from near-term chicken embryos incubated under normoxic or hypoxic conditions, we determined the expression of the H2S gene CTH (i.e. cystathionine γ-lyase) (via quantitative PCR), the production of H2S (enzymatic activity), the DNA methylation profile (pyrosequencing) and vasodilator reactivity (wire myography) in the presence and absence of NAC treatment. The data show that FGR and hypoxia increased CTH expression in the embryonic/fetal vasculature in both species. NAC treatment increased aortic CTH expression and H2S production and enhanced third-order femoral artery dilator responses to the H2S donor sodium hydrosulphide in chicken embryos. NAC treatment also restored impaired endothelial relaxation in human third-to-fourth order chorionic arteries from FGR pregnancies and in third-order femoral arteries from hypoxic chicken embryos. This NAC-induced protection against endothelial dysfunction in hypoxic chicken embryos was mediated via nitric oxide independent mechanisms. Both developmental hypoxia and NAC promoted vascular changes in CTH DNA and NOS3 methylation patterns in chicken embryos. Combined, therefore, the data support that the effects of NAC and H2S offer a powerful mechanism of human translational potential against fetal cardiovascular dysfunction in complicated pregnancy. KEY POINTS: Gestation complicated by chronic fetal hypoxia and fetal growth restriction (FGR) increases a prenatal origin of cardiovascular disease in offspring, increasing interest in antenatal therapy to prevent against a fetal origin of cardiovascular dysfunction. We investigated the effects between N-acetylcysteine (NAC) and hydrogen sulphide (H2S) in the vasculature in FGR human pregnancy and in chronically hypoxic chicken embryos. Combining cellular, molecular, epigenetic and functional studies, we show that the vascular expression and synthesis of H2S is enhanced in hypoxic and FGR unborn offspring in both species and this acts to protect their vasculature. Therefore, the NAC/H2S pathway offers a powerful therapeutic mechanism of human translational potential against fetal cardiovascular dysfunction in complicated pregnancy.

Pharmacological and molecular mechanisms of miRNA-based therapies for targeting cardiovascular dysfunction.

Advances in understanding gene expression regulation through epigenetic mechanisms have contributed to elucidating the regulatory mechanisms of noncoding RNAs as pharmacological targets in several diseases. MicroRNAs (miRs) are a class of evolutionarily conserved, short, noncoding RNAs regulating in a concerted manner gene expression at the post-transcriptional level by targeting specific sequences of the 3'-untranslated region of mRNA. Conversely, mechanisms of cardiovascular disease (CVD) remain largely elusive due to their life-course origins, multifactorial pathophysiology, and co-morbidities. In this regard, CVD treatment with conventional medications results in therapeutic failure due to progressive resistance to monotherapy, which overlooks the multiple factors involved, and reduced adherence to poly-pharmacology approaches. Consequently, considering its role in regulating complete gene pathways, miR-based drugs have appreciably progressed into preclinical and clinical testing. This review summarizes the current knowledge about the mechanisms of miRs in cardiovascular disease, focusing specifically on describing how clinical chemistry and physics have improved the stability of the miR molecule. In addition, a comprehensive review of the main miRs involved in cardiovascular disease and the clinical trials in which these molecules are used as active pharmacological molecules is provided.

Obesogenic Diet in Mice Leads to Inflammation and Oxidative Stress in the Mother in Association with Sex-Specific Changes in Fetal Development, Inflammatory Markers and Placental Transcriptome.

BACKGROUND: Obesity during pregnancy is related to adverse maternal and neonatal outcomes. Factors involved in these outcomes may include increased maternal insulin resistance, inflammation, oxidative stress, and nutrient mishandling. The placenta is the primary determinant of fetal outcomes, and its function can be impacted by maternal obesity. The aim of this study on mice was to determine the effect of obesity on maternal lipid handling, inflammatory and redox state, and placental oxidative stress, inflammatory signaling, and gene expression relative to female and male fetal growth. METHODS: Female mice were fed control or obesogenic high-fat/high-sugar diet (HFHS) from 9 weeks prior to, and during, pregnancy. On day 18.5 of pregnancy, maternal plasma, and liver, placenta, and fetal serum were collected to examine the immune and redox states. The placental labyrinth zone (Lz) was dissected for RNA-sequencing analysis of gene expression changes. RESULTS: the HFHS diet induced, in the dams, hepatic steatosis, oxidative stress (reduced catalase, elevated protein oxidation) and the activation of pro-inflammatory pathways (p38-MAPK), along with imbalanced circulating cytokine concentrations (increased IL-6 and decreased IL-5 and IL-17A). HFHS fetuses were asymmetrically growth-restricted, showing sex-specific changes in circulating cytokines (GM-CSF, TNF-α, IL-6 and IFN-γ). The morphology of the placenta Lz was modified by an HFHS diet, in association with sex-specific alterations in the expression of genes and proteins implicated in oxidative stress, inflammation, and stress signaling. Placental gene expression changes were comparable to that seen in models of intrauterine inflammation and were related to a transcriptional network involving transcription factors, LYL1 and PLAG1. CONCLUSION: This study shows that fetal growth restriction with maternal obesity is related to elevated oxidative stress, inflammatory pathways, and sex-specific placental changes. Our data are important, given the marked consequences and the rising rates of obesity worldwide.

Epigenética y obesidad / Epigenetics and obesity

La evidencia indica que la exposición a diversas condiciones ambientales en etapas tempranas de la vida puede inducir alteraciones persistentes en el epigenoma. Los estudios epigenómicos en sujetos obesos han permitido evaluar el papel de los mecanismos epigenéticos en el origen y desarrollo de la obesidad. La presente revisión aborda estudios que dan cuenta de la asociación entre la obesidad y metilación global del genoma (ADN), analizando el potencial impacto de intervenciones previas y posteriores al nacimiento que afectan la metilación del ADN y la obesidad en etapas más avanzadas de la vida. Estudios realizados principalmente en leucocitos, han logrado identificar sitios del ADN diferencialmente metilados asociados con obesidad. Estudios hasta la fecha no han demostrado que dichos cambios en metilación sean revertidos luego de bajar de peso. Esto contrasta con resultados iniciales en este campo, que sugieren que existirían marcadores epigenéticos presentes desde el nacimiento que permitirían definir el riesgo de obesidad durante el curso de la vida. La evidencia actual sugiere que algunas marcas epigenéticas son modificables, basándonos en la exposición en la vida intrauterina y también por los hábitos dietarios y de actividad fisica durante las etapas del crecimiento y en la adultez. Esto sugiere que existe la oportunidad de intervenir durante la gestación o en la vida posnatal temprana, que modificaría los perfiles epigenéticos desfavorables e idealmente contribuiría a prevenir la obesidad en los sujetos o poblaciones susceptibles.

Current evidence supports the notion that exposure to various environmental conditions in early life may induce permanent changes in the epigenome that persist throughout the life-course. This article focuses on early changes associated with obesity in adult life. A review is presented on the factors that induce changes in whole genome (DNA) methylation in early life that are associated with adult onset obesity and related disorders. In contrast, reversal of epigenetic changes associated with weight loss in obese subjects has not been demonstrated. This contrasts with well-established associations found between obesity related DNA methylation patterns at birth and adult onset obesity and diabetes. Epigenetic markers may serve to screen indivuals at risk for obesity and assess the effects of interventions in early life that may delay or prevent obesity in early life. This might contribute to lower the obesity-related burden of death and disability at the population level. The available evidence indicates that epigenetic marks are in fact modifiable, based on modifications in the intrauterine environment and changes in food intake, physical activity and dietary patterns patterns during pregnancy and early years of adult life. This offers the opportunity to intervene before conception, during pregnancy, infancy, childhood, and also in later life. There must be documentation on the best preventive actions in terms of diet and physical activity that will modify or revert the adverse epigenetic markers, thus preventing obesity and diabetes in suceptible individuals and populations.

Conceptos generales de epigenética: proyecciones en pediatría / General concepts of epigenetics: projections in paediatrics

La asociación entre factores ambientales presentes durante el desarrollo embrionario/fetal y enfermedades que puedan presentarse durante la vida representa un campo de creciente interés. En este contexto la evidencia actual apoya fuertemente que alteraciones en el crecimiento intrauterino y durante los primeros años de vida presentan una fuerte influencia en el riesgo de padecer enfermedades crónicas que en muchos casos pudiera ser mayor que la carga genética del paciente. La persistencia y reproducibilidad de los fenotipos asociados a alteraciones en el desarrollo temprano sugieren la participación de mecanismos moleculares que registran dichas modificaciones (i.e. mecanismos epigenéticos) generando una «reprogramación¼ celular y fisiológica. Esta revisión es la introducción a una serie de 5 artículos en torno a la participación de los mecanismos epigenéticos en el desarrollo de enfermedades crónicas (i.e. cardiovasculares, metabólicas, asma/alergias y cáncer) y su relación con el origen de dichas enfermedades en etapas tempranas del desarrollo. El objetivo de esta serie es mostrar el estado actual de esta área de la investigación y presentar los desafíos e interrogantes futuros en los cuales la pediatría tiene un papel preponderante, desarrollando estrategias para la prevención, detección precoz y seguimiento.

Current evidence supports the notion that alterations in intrauterine growth and during the first years of life have a substantial effect on the risk for the development of chronic disease, which in some cases is even higher than those due to genetic factors. The persistence and reproducibility of the phenotypes associated with altered early development suggest the participation of mechanisms that would record environmental cues, generating a cellular reprogramming (i.e. epigenetic mechanisms). This review is an introduction to a series of five articles focused on the participation of epigenetic mechanisms in the development of highly prevalent chronic diseases (i.e. cardiovascular, metabolic, asthma/allergies and cancer) and their origins in the foetal and neonatal period. This series of articles aims to show the state of the art in this research area and present the upcoming clues and challenges, in which paediatricians have a prominent role, developing strategies for the prevention, early detection and follow-up.

Epigenética en enfermedades alérgicas y asma / Epigenetics in allergic diseases and asthma

Las enfermedades alérgicas y el asma son el resultado de complejas interacciones entre la predisposición genética y factores ambientales. El asma es una de las enfermedades crónicas más prevalentes en niños. En este artículo se revisan algunos factores ambientales como la exposición a alérgenos, tabaco, bacterias, componentes microbianos, dieta, obesidad y estrés, que intervienen durante la vida intrauterina y la infancia en la regulación epigenética de las enfermedades alérgicas y el asma. La revisión se realiza en tres tipos de modelos: in-vitro, animales y humanos.

Allergic diseases and asthma are the result of complex interactions between genetic predisposition and environmental factors. Asthma is one of the most prevalent chronic disease among children. In this article we review some environmental factors like: allergen exposition, tobacco, bacteria, microbial components, diet, obesity and stress, which influences during intrauterine and infancy life in the epigenetic regulation of asthma and allergic diseases. The review has been done in three models: in-vitro, animal and human.