Project description:Dysregulated maternal fatty acid metabolism increases the risk of congenital heart disease (CHD) in offspring with an unknown mechanism, and the effect of folic acid fortification in preventing CHD is controversial. Using gas chromatography coupled to either a flame ionization detector or mass spectrometer (GC-FID/MS) analysis, we find that the palmitic acid (PA) concentration increases significantly in serum samples of pregnant women bearing children with CHD. Feeding pregnant mice with PA increased CHD risk in offspring and cannot be rescued by folic acid supplementation. We further find that PA promotes methionyl-tRNA synthetase (MARS) expression and protein lysine homocysteinylation (K-Hcy) of GATA4 and results in GATA4 inhibition and abnormal heart development. Targeting K-Hcy modification by either genetic ablation of Mars or using N-acetyl-L-cysteine (NAC) decreases CHD onset in high-PA-diet-fed mice. In summary, our work links maternal malnutrition and MARS/K-Hcy with the onset of CHD and provides a potential strategy in preventing CHD by targeting K-Hcy other than folic acid supplementation.
2023-03-24 | MTBLS6982 | MetaboLights
Project description:Association of MTR gene polymorphisms and congenital heart disease
Project description:Congenital heart disease (CHD) is the most prevalent structural malformations of the heart affecting ∼1% of live births. To date, both damaging genetic variations and adverse environmental exposure such as maternal diabetes have been found to cause CHD. Clinical studies show ∼fivefold higher risk of CHD in the offspring of mothers with pregestational diabetes. Maternal pregestational diabetes affects the gene regulatory networks key to proper cardiac development in the fetus. However, the cell-type specificity of these gene regulatory responses to maternal diabetes and their association with the observed cardiac defects in the fetuses remains unknown. To uncover the transcriptional responses to maternal diabetes in the early embryonic heart, we used an established murine model of pregestational diabetes. In this model, we have previously demonstrated an increased incidence of CHD. Here, we show maternal hyperglycemia (matHG) elicits diverse cellular responses during heart development by single-cell RNA-sequencing in embryonic hearts exposed to control and matHG environment. Through differential gene-expression and pseudotime trajectory analyses of this data, we identified changes in lineage specifying transcription factors, predominantly affecting Isl1+ second heart field progenitors and Tnnt2+cardiomyocytes with matHG. Using in vivo cell-lineage tracing studies, we confirmed that matHG exposure leads to impaired second heart field-derived cardiomyocyte differentiation. Finally, this work identifies matHG-mediated transcriptional determinants in cardiac cell lineages elevate CHD risk and show perturbations in Isl1-dependent gene-regulatory network (Isl1-GRN) affect cardiomyocyte differentiation. Functional analysis of this GRN in cardiac progenitor cells will provide further mechanistic insights into matHG-induced severity of CHD associated with diabetic pregnancies.
Project description:Congenital heart defects (CHD) are one of the most common defects in offspring of diabetic mothers. There is a clear association between maternal diabetes and CHD; however the underlying molecular mechanism remains unknown. We hypothesized that maternal diabetes affects with the expression of early developmental genes that regulate the essential developmental processes of the heart, thereby resulting in the pathogenesis of CHD. We analyzed genome-wide expression profiling in the developing heart of embryos from diabetic and control mice by using the oligonucleotide microarray. Microarray analysis revealed that a total of 878 genes exhibited more than 1.5 fold changes in expression level in the hearts of experimental embryos in either E13.5 or E15.5 compared with their respective controls. Expression pattern of genes that is differentially expressed in the developing heart was further examined by the real-time reverse transcriptase-polymerase chain reaction. Several genes involved in a number of molecular signaling pathways such as apoptosis, proliferation, migration and differentiation in the developing heart were differentially expressed in embryos of diabetic pregnancy. It is concluded that altered expression of several genes involved in heart development may contribute to CHD in offspring of diabetic mothers.
Project description:Genome-wide association studies have identified a small region at chromosome 9p21.3 strongly associated with coronary heart disease risk. The region contains no protein-coding genes and the mechanism underlying its association with heart disease is unknown. We investigated associations between rs1333049, a single nucleotide polymorphism representing the 9p21.3 locus, and levels of cardiac gene expression in myocardial tissue from donors with no documented history of heart disease.
Project description:Genome-wide association studies have identified a small region at chromosome 9p21.3 strongly associated with coronary heart disease risk. The region contains no protein-coding genes and the mechanism underlying its association with heart disease is unknown. We investigated associations between rs1333049, a single nucleotide polymorphism representing the 9p21.3 locus, and levels of cardiac gene expression in myocardial tissue from donors with no documented history of heart disease. Individual myocardial gene expression profiles were generated with Affymetrix Human Gene 1.0 ST arrays (n=108). DNA genotyping was performed with Taqman assays. Associations between genotype and gene expression were analyzed assuming a recessive effect.
Project description:Maternal exposure to balanced nutrition is critical for supporting embryonic development. Exposure to imbalanced nutrition during pregnancy, such as a high-fat diet (HFD), has been reported to negatively impact offspring, leading to conditions such as congenital heart disease. One possible mechanism is that metabolic stress from imbalanced food intake alters the function of epigenetic regulators, leading to abnormal transcriptional output in embryos. In this study, we observed that maternal exposure to a high-fat diet led to noncompaction cardiomyopathy (NCC) in embryos at E15.5. At the molecular level, maternal HFD exposure resulted in significantly reduced 5hmC production and chromatin remodeling in embryonic heart tissue collected from E15.5 embryos. Interestingly, maternal vitamin C treatment countered the negative impact of HFD exposure and restored the metabolic changes observed in pregnant mice, as well as the NCC phenotype observed in E15.5 embryos. This restoration is possibly due to the replenishment of iron, a co-factor of the Tet enzyme, in its reduced form. We further used a cardiac-specific Tet-triple knockout mouse model to confirm that the cardioprotective outcomes of maternal vitamin C treatment in HFD conditions are attributable to the enhanced activity of TET enzymes. Collectively, our results suggest a crosstalk between maternal nutrition exposure, such as HFD or vitamin C, and epigenetic rewriting during embryonic heart development。
Project description:Maternal diabetes is a recognized risk factor for both short-term and long-term complications in offspring. Beyond the direct teratogenicity of maternal diabetes, the intrauterine environment can influence offspring cardiovascular health. Abnormalities in the cardiac sympathetic system are implicated in conditions such as sudden infant death syndrome, cardiac arrhythmic death, heart failure, and certain congenital heart defects in children from diabetic pregnancies. However, the mechanisms by which maternal diabetes affect the development of the cardiac sympathetic system and consequently, heightening health risks and predisposing to cardiovascular disease remain poorly understood. In this study, we present a comprehensive analysis of the combined impact of a Hif1a-deficient sympathetic system and the maternal diabetes environment on both heart development and the formation of the cardiac sympathetic system. The synergic negative effect of exposure to maternal diabetes and Hif1a deficiency resulted in the most pronounced deficit in cardiac sympathetic innervation and the development of adrenal medulla. Abnormalities in the cardiac sympathetic system were accompanied by a smaller heart, reduced ventricular wall thickness, dilated subepicardial veins, and coronary arteries in the myocardium, along with anomalies in the branching and connections of the main coronary arteries. Transcriptional profiling by RNA-seq revealed significant transcriptome changes in Hif1a-deficient sympathetic neurons, primarily associated with cell cycle regulation, proliferation, and mitosis, explaining the shrinkage of the sympathetic neuron population. Our data demonstrate that a failure to adequately activate HIF-1α regulatory pathway, particularly in the context of maternal diabetes, may contribute to abnormalities in the cardiac sympathetic system. In conclusion, our findings indicate that the interplay between deficiencies in the cardiac sympathetic system and subtle structural alternations in the vasculature, microvasculature, and myocardium during heart development not only increases the risk of cardiovascular disease but also diminishes the adaptability to the stress associated with the transition to extrauterine life, thus, increasing the risk of neonatal death.