ABSTRACT
Maternal exposure to nitrogen dioxide (NO2) poses a risk for morbidity and mortality in infantile congenital heart diseases and even adult cardiovascular diseases. However, the experimental evidence supporting these effects is insufficient, and the related regulatory mechanisms are unknown. In the present study, we aimed to determine whether maternal NO2 exposure causes cardiac hypertrophy-related consequences in offspring, and if so, how these adverse effects occur in the postnatal heart. The results indicate that in mice, maternal NO2 exposure causes cardiac hypertrophy in male offspring. This altered phenotype was accompanied by increased expression of atrial natriuretic peptide, B-type natriuretic peptide, bone morphogenetic protein 10 and ß-myosin heavy chain and elevated activities of cardiomyocyte injury markers, including serum glutamate-oxaloacetate transaminase, lactate dehydrogenase and kinases creatine phosphokinase (CK-MB) in serum. The cardiac-specific transcription factor Csx/Nkx2.5 played an important role in the induction of cardiac hypertrophy and cardiomyocyte injury, and the action was associated with ROS-HIF-1α transcriptional regulation and DNA hypomethylation modification.
Subject(s)
Cardiomegaly/chemically induced , Homeobox Protein Nkx-2.5/genetics , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Maternal Exposure , Nitrogen Dioxide/toxicity , Reactive Oxygen Species/metabolism , Animals , Aspartate Aminotransferases/blood , Atrial Natriuretic Factor/blood , Biomarkers/blood , Bone Morphogenetic Proteins/blood , Cardiomegaly/genetics , Creatine Kinase/blood , DNA Methylation , Female , Gene Expression Regulation , Humans , L-Lactate Dehydrogenase/blood , Male , Mice , Natriuretic Peptide, Brain/blood , Pregnancy , Ventricular Myosins/bloodABSTRACT
About 10% of cases of hypertrophic cardiomyopathy (HCM) evolve into dilated cardiomyopathy (DCM) with unknown causes. We studied 11 unrelated patients (pts) with HCM who progressed to DCM (group A) and 11 who showed "typical" HCM (group B). Mutational analysis of the beta-myosin heavy chain (MYH7), myosin-binding protein C (MYBPC3), and cardiac troponin T (TNNT2) genes demonstrated eight mutations affecting MYH7 or MYBPC3 gene, five of which were new mutations. In group A-pts, the first new mutation occurred in the myosin head-rod junction and the second occurred in the light chain-binding site. The third new mutation leads to a MYBPC3 lacking titin and myosin binding sites. In group B, two pts with severe HCM carried two homozygous MYBPC3 mutations and one with moderate hypertrophy was a compound heterozygous for MYBPC3 gene. We identified five unreported mutations, potentially "malignant" defects as for the associated phenotypes, but no specific mutations of HCM/DCM.
