ABSTRACT
BACKGROUND: Smooth muscle cells (SMC), the major cell type in atherosclerotic plaques, are vital in coronary artery diseases (CADs). SMC phenotypic transition, which leads to the formation of various cell types in atherosclerotic plaques, is regulated by a network of genetic and epigenetic mechanisms and governs the risk of disease. The involvement of long noncoding RNAs (lncRNAs) has been increasingly identified in cardiovascular disease. However, SMC lncRNAs have not been comprehensively characterized, and their regulatory role in SMC state transition remains unknown. METHODS: A discovery pipeline was constructed and applied to deeply strand-specific RNA sequencing from perturbed human coronary artery SMC with different disease-related stimuli, to allow for the detection of novel lncRNAs. The functional relevance of a select few novel lncRNAs were verified in vitro. RESULTS: We identified 4579 known and 13 655 de novo lncRNAs in human coronary artery SMC. Consistent with previous long noncoding RNA studies, these lncRNAs overall have fewer exons, are shorter in length than protein-coding genes (pcGenes), and have relatively low expression level. Genomic location of these long noncoding RNA is disproportionately enriched near CAD-related TFs (transcription factors), genetic loci, and gene regulators of SMC identity, suggesting the importance of their function in disease. Two de novo lncRNAs, ZIPPOR (ZEB-interacting suppressor) and TNS1-AS2 (TNS1-antisense 2), were identified by our screen. Combining transcriptional data and in silico modeling along with in vitro validation, we identified CAD gene ZEB2 as a target through which these lncRNAs exert their function in SMC phenotypic transition. CONCLUSIONS: Expression of a large and diverse set of lncRNAs in human coronary artery SMC are highly dynamic in response to CAD-related stimuli. The dynamic changes in expression of these lncRNAs correspond to alterations in transcriptional programs that are relevant to CAD, suggesting a critical role for lncRNAs in SMC phenotypic transition and human atherosclerotic disease.
Subject(s)
Plaque, Atherosclerotic , RNA, Long Noncoding , Humans , RNA, Long Noncoding/metabolism , Plaque, Atherosclerotic/metabolism , Transcription Factors/metabolism , Phenotype , Myocytes, Smooth Muscle/metabolismABSTRACT
OBJECTIVE: The goal of this review is to discuss the implementation of genome-wide association studies to identify causal mechanisms of vascular disease risk. APPROACH AND RESULTS: The history of genome-wide association studies is described, the use of imputation and the creation of consortia to conduct meta-analyses with sufficient power to arrive at consistent associated loci for vascular disease. Genomic methods are described that allow the identification of causal variants and causal genes and how they impact the disease process. The power of single-cell analyses to promote genome-wide association studies of causal gene function is described. CONCLUSIONS: Genome-wide association studies represent a paradigm shift in the study of cardiovascular disease, providing identification of genes, cellular phenotypes, and disease pathways that empower the future of targeted drug development.
Subject(s)
Cardiovascular Diseases , Vascular Diseases , Humans , Genome-Wide Association Study , Genomics , Drug DevelopmentABSTRACT
In utero exposure to diesel exhaust air pollution has been associated with increased adult susceptibility to heart failure in mice, but the mechanisms by which this exposure promotes susceptibility to heart failure are poorly understood. To identify the potential transcriptional effects that mediate this susceptibility, we have performed RNA sequencing analysis on adult hearts from mice that were exposed to diesel exhaust in utero and that have subsequently undergone transverse aortic constriction. We identified 3 target genes, Mir133a-2, Ptprf, and Pamr1, which demonstrate dysregulation after exposure and aortic constriction. Examination of expression patterns in human heart tissues indicates a correlation between expression and heart failure. We subsequently assessed DNA methylation modifications at these candidate loci in neonatal cultured cardiac myocytes after in utero exposure to diesel exhaust and found that the promoter for Mir133a-2 is differentially methylated. These target genes in the heart are the first genes to be identified that likely play an important role in mediating adult sensitivity to heart failure. We have also shown a change in DNA methylation within cardiomyocytes as a result of in utero exposure to diesel exhaust.-Goodson, J. M., Weldy, C. S., MacDonald, J. W., Liu, Y., Bammler, T. K., Chien, W.-M., Chin, M. T. In utero exposure to diesel exhaust particulates is associated with an altered cardiac transcriptional response to transverse aortic constriction and altered DNA methylation.
Subject(s)
Aortic Diseases , DNA Methylation/drug effects , Maternal Exposure/adverse effects , Myocardium/metabolism , Prenatal Exposure Delayed Effects/metabolism , Transcription, Genetic/drug effects , Vehicle Emissions/toxicity , Animals , Aortic Diseases/chemically induced , Aortic Diseases/congenital , Aortic Diseases/metabolism , Aortic Diseases/pathology , Female , Gene Expression Regulation/drug effects , Male , Mice , MicroRNAs/biosynthesis , Myocardium/pathology , Pregnancy , Prenatal Exposure Delayed Effects/pathology , Receptor-Like Protein Tyrosine Phosphatases, Class 2/biosynthesis , Serine Endopeptidases/biosynthesis , Serine ProteasesABSTRACT
CHF1/Hey2 is a Notch-responsive basic helix-loop-helix transcription factor involved in cardiac development. Common variants in Hey2 are associated with Brugada syndrome. We hypothesized that absence of CHF1/Hey2 would result in abnormal cellular electrical activity, altered cardiac conduction system (CCS) development, and increased arrhythmogenesis. We isolated neonatal CHF/Hey2-knockout (KO) cardiac myocytes and measured action potentials and ion channel subunit gene expression. We also crossed myocardial-specific CHF1/Hey2-KO mice with cardiac conduction system LacZ reporter mice and stained for conduction system tissue. We also performed ambulatory ECG monitoring for arrhythmias and heart rate variability. Neonatal cardiomyocytes from CHF1/Hey2-KO mice demonstrate a 50% reduction in action potential dV/dT, a 50-75% reduction in SCN5A, KCNJ2, and CACNA1C ion channel subunit gene expression, and an increase in delayed afterdepolarizations from 0/min to 12/min. CHF1/Hey2 cKO CCS-lacZ mice have a â¼3-fold increase in amount of CCS tissue. Ambulatory ECG monitoring showed no difference in cardiac conduction, arrhythmias, or heart rate variability. Wild-type cells or animals were used in all experiments. CHF1/Hey2 may contribute to Brugada syndrome by influencing the expression of SCN5A and formation of the cardiac conduction system, but its absence does not cause baseline conduction defects or arrhythmias in the adult mouse.-Hartman, M. E., Liu, Y., Zhu, W.-Z., Chien, W.-M., Weldy, C. S., Fishman, G. I., Laflamme, M. A., Chin, M. T. Myocardial deletion of transcription factor CHF1/Hey2 results in altered myocyte action potential and mild conduction system expansion but does not alter conduction system function or promote spontaneous arrhythmias.
Subject(s)
Action Potentials/genetics , Arrhythmias, Cardiac/genetics , Basic Helix-Loop-Helix Transcription Factors/genetics , Heart Conduction System/abnormalities , Myocardium/metabolism , Myocytes, Cardiac/metabolism , Repressor Proteins/genetics , Transcription Factors/genetics , Animals , Arrhythmias, Cardiac/metabolism , Basic Helix-Loop-Helix Transcription Factors/metabolism , Brugada Syndrome , Cardiac Conduction System Disease , Heart Conduction System/metabolism , Heart Rate/genetics , Mice , Mice, Inbred C57BL , Mice, Knockout , Repressor Proteins/metabolism , Transcription Factors/metabolismABSTRACT
Mapping the genomic architecture of complex disease has been predicated on the understanding that genetic variants influence disease risk through modifying gene expression. However, recent discoveries have revealed that a significant burden of disease heritability in common autoinflammatory disorders and coronary artery disease is mediated through genetic variation modifying post-transcriptional modification of RNA through adenosine-to-inosine (A-to-I) RNA editing. This common RNA modification is catalyzed by ADAR enzymes, where ADAR1 edits specific immunogenic double stranded RNA (dsRNA) to prevent activation of the double strand RNA (dsRNA) sensor MDA5 ( IFIH1 ) and stimulation of an interferon stimulated gene (ISG) response. Multiple lines of human genetic data indicate impaired RNA editing and increased dsRNA sensing to be an important mechanism of coronary artery disease (CAD) risk. Here, we provide a crucial link between observations in human genetics and mechanistic cell biology leading to progression of CAD. Through analysis of human atherosclerotic plaque, we implicate the vascular smooth muscle cell (SMC) to have a unique requirement for RNA editing, and that ISG induction occurs in SMC phenotypic modulation, implicating MDA5 activation. Through culture of human coronary artery SMCs, generation of a conditional SMC specific Adar1 deletion mouse model on a pro-atherosclerosis background, and with incorporation of single cell RNA sequencing cellular profiling, we further show that Adar1 controls SMC phenotypic state, is required to maintain vascular integrity, and controls progression of atherosclerosis and vascular calcification. Through this work, we describe a fundamental mechanism of CAD, where cell type and context specific RNA editing and sensing of dsRNA mediates disease progression, bridging our understanding of human genetics and disease causality.
ABSTRACT
BACKGROUND: Fine particulate air pollution (PM2.5) is a global health concern, as exposure to PM2.5 has consistently been found to be associated with increased cardiovascular morbidity and mortality. Although adult exposure to traffic related PM2.5, which is largely derived from diesel exhaust (DE), has been associated with increased cardiac hypertrophy, there are limited investigations into the potential effect of in utero and early life exposure on adult susceptibility to heart disease. In this study, we investigate the effect of in utero and early life exposure to DE on adult susceptibility to heart failure. METHODS: Female C57BL/6 J mice were exposed to either filtered air (FA) or DE for 3 weeks (≈ 300 µg/m3 PM2.5 for 6 hours/day, 5 days/week) and then introduced to male breeders for timed matings. Female mice were exposed to either FA or DE throughout pregnancy and until offspring were 3 weeks of age. Offspring were then transferred to either FA or DE for an additional 8 weeks of exposure. At 12 weeks of age, male offspring underwent a baseline echocardiographic assessment, followed by a sham or transverse aortic constriction (TAC) surgery to induce pressure overload. Following sacrifice three weeks post surgery, ventricles were processed for histology to assess myocardial fibrosis and individual cardiomyocyte hypertrophy. mRNA from lung tissue was isolated to measure expression of inflammatory cytokines IL6 and TNFα. RESULTS: We observed that mice exposed to DE during in utero and early life development have significantly increased susceptibility to cardiac hypertrophy, systolic failure, myocardial fibrosis, and pulmonary congestion following TAC surgery compared to FA control, or adult DE exposed mice. In utero and early life DE exposure also strongly modified the inflammatory cytokine response in the adult lung. CONCLUSIONS: We conclude that exposure to diesel exhaust air pollution during in utero and early life development in mice increases adult susceptibility to heart failure. The results of this study may imply that the effects of air pollution on cardiovascular disease in human populations may be strongly mediated through a 'fetal origins' of adult disease pathway. Further investigations on this potential pathway of disease are warranted.
Subject(s)
Environmental Exposure , Heart Failure/chemically induced , Prenatal Exposure Delayed Effects , Vehicle Emissions , Animals , Cytokines/metabolism , Female , Mice , PregnancyABSTRACT
BACKGROUND: Strong associations have been observed between exposure to fine ambient particulate matter (PM2.5) and adverse cardiovascular outcomes. In particular, exposure to traffic related PM2.5 has been associated with increases in left ventricular hypertrophy, a strong risk factor for cardiovascular mortality. As much of traffic related PM2.5 is derived from diesel exhaust (DE), we investigated the effects of chronic DE exposure on cardiac hypertrophy and heart failure in the adult mouse by exposing mice to DE combined with either of two mouse models of cardiac hypertrophy: angiotensin II infusion or pressure overload induced by transverse aortic banding. METHODS: Wild type male C57BL/6 J mice were either infused with angiotensin II (800 ng/kg/min) via osmotic minipump implanted subcutaneously for 1 month, or underwent transverse aortic banding (27 gauge needle 1 week for observing acute reactions, 26 gauge needle 3 months or 6 months for observing chronic reactions). Vehicle (saline) infusion or sham surgery was used as a control. Shortly after surgery, mice were transferred to our exposure facility and randomly assigned to either diesel exhaust (300 or 400 µg/m(3)) or filtered air exposures. After reaching the end of designated time points, echocardiography was performed to measure heart structure and function. Gravimetric analysis was used to measure the ventricular weight to body weight ratio. We also measured heart rate by telemetry using implanted ambulatory ECG monitors. RESULTS: Both angiotensin II and transverse aortic banding promoted cardiac hypertrophy compared to vehicle or sham controls. Transverse aortic banding for six months also promoted heart failure in addition to cardiac hypertrophy. In all cases, DE failed to exacerbate the development of hypertrophy or heart failure when compared to filtered air controls. Prolonged DE exposure also led to a decrease in average heart rate. CONCLUSIONS: Up to 6-months of DE exposure had no effect on cardiac hypertrophy and heart function induced by angiotensin II stimulation or pressure overload in adult C57BL/6 J mice. This study highlights the potential importance of particle constituents of ambient PM2.5 to elicit cardiotoxic effects. Further investigations on particle constituents and cardiotoxicity are warranted.
Subject(s)
Air Pollutants/toxicity , Cardiomegaly/chemically induced , Heart Failure/chemically induced , Inhalation Exposure/adverse effects , Particulate Matter/toxicity , Vehicle Emissions/toxicity , Air Pollutants/chemistry , Angiotensin II/administration & dosage , Angiotensin II/pharmacology , Animals , Cardiomegaly/diagnostic imaging , Disease Models, Animal , Disease Progression , Echocardiography , Heart Failure/diagnostic imaging , Heart Rate/drug effects , Male , Mice , Mice, Inbred C57BL , Particle Size , Particulate Matter/chemistry , Time FactorsABSTRACT
CONTEXT: Inhalation of fine particulate matter (PM2.5) is associated with acute pulmonary inflammation and impairments in cardiovascular function. In many regions, PM2.5 is largely derived from diesel exhaust (DE), and these pathophysiological effects may be due in part to oxidative stress resulting from DE inhalation. The antioxidant glutathione (GSH) is important in limiting oxidative stress-induced vascular dysfunction. The rate-limiting enzyme in GSH synthesis is glutamate cysteine ligase and polymorphisms in its catalytic and modifier subunits (GCLC and GCLM) have been shown to influence vascular function and risk of myocardial infarction in humans. OBJECTIVE: We hypothesized that compromised de novo synthesis of GSH in Gclmâ»/⺠mice would result in increased sensitivity to DE-induced lung inflammation and vascular effects. MATERIALS AND METHODS: WT and Gclmâ»/⺠mice were exposed to DE via inhalation (300 µg/m³) for 6 h. Neutrophil influx into the lungs, plasma GSH redox potential, vascular reactivity of aortic rings and aortic nitric oxide (NOâ¢) were measured. RESULTS: DE inhalation resulted in mild bronchoalveolar neutrophil influx in both genotypes. DE-induced effects on plasma GSH oxidation and acetylcholine (ACh)-relaxation of aortic rings were only observed in Gclmâ»/⺠mice. Contrary to our hypothesis, DE exposure enhanced ACh-induced relaxation of aortic rings in Gclmâ»/⺠mice. DISCUSSION AND CONCLUSION: THESE data support the hypothesis that genetic determinants of antioxidant capacity influence the biological effects of acute inhalation of DE. However, the acute effects of DE on the vasculature may be dependent on the location and types of vessels involved. Polymorphisms in GSH synthesis genes are common in humans and further investigations into these potential gene-environment interactions are warranted.
Subject(s)
Air Pollutants/toxicity , Glutamate-Cysteine Ligase/genetics , Vehicle Emissions/toxicity , Administration, Inhalation , Animals , Aorta/physiology , Bronchoalveolar Lavage Fluid/immunology , Female , Glutathione/blood , Glutathione Disulfide/blood , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , Neutrophils/immunology , Nitric Oxide/metabolism , Oxidation-Reduction , Pneumonia/chemically induced , Pneumonia/immunology , Pneumonia/metabolism , Pneumonia/physiopathology , VasodilationABSTRACT
Chronic ventricular pacing can lead to pacing-induced cardiomyopathy (PICM). Clinical data alone is insufficient to predict who will develop PICM. Our study aimed to evaluate the circulating miR profile associated with chronic right ventricular pacing in children with congenital complete AV block (CCAVB) and to identify candidate miRs for longitudinal monitoring. Clinical data and blood were collected from chronically paced children (N = 9) and compared with non-paced controls (N = 13). miR microarrays from the buffy coat revealed 488 differentially regulated miRs between groups. Pathway analysis predicted both adaptive and maladaptive miR signaling associated with chronic pacing despite preserved ventricular function. Greater profibrotic signaling (miRs-92a, 130, 27, 29) and sodium and calcium channel dysregulation (let-7) were seen in those paced > 10 years with the most dyregulation seen in a patient with sudden death vs. those paced < 10 years. These miRs may help to identify early adverse remodeling in this population.
Subject(s)
Atrioventricular Block , Cardiomyopathies , MicroRNAs , Humans , Child , Atrioventricular Block/therapy , Pilot Projects , Cardiac Pacing, ArtificialABSTRACT
The combinatorial effect of genetic variants is often assumed to be additive. Although genetic variation can clearly interact non-additively, methods to uncover epistatic relationships remain in their infancy. We develop low-signal signed iterative random forests to elucidate the complex genetic architecture of cardiac hypertrophy. We derive deep learning-based estimates of left ventricular mass from the cardiac MRI scans of 29,661 individuals enrolled in the UK Biobank. We report epistatic genetic variation including variants close to CCDC141, IGF1R, TTN, and TNKS. Several loci not prioritized by univariate genome-wide association analysis are identified. Functional genomic and integrative enrichment analyses reveal a complex gene regulatory network in which genes mapped from these loci share biological processes and myogenic regulatory factors. Through a network analysis of transcriptomic data from 313 explanted human hearts, we show that these interactions are preserved at the level of the cardiac transcriptome. We assess causality of epistatic effects via RNA silencing of gene-gene interactions in human induced pluripotent stem cell-derived cardiomyocytes. Finally, single-cell morphology analysis using a novel high-throughput microfluidic system shows that cardiomyocyte hypertrophy is non-additively modifiable by specific pairwise interactions between CCDC141 and both TTN and IGF1R. Our results expand the scope of genetic regulation of cardiac structure to epistasis.
ABSTRACT
The combinatorial effect of genetic variants is often assumed to be additive. Although genetic variation can clearly interact non-additively, methods to uncover epistatic relationships remain in their infancy. We develop low-signal signed iterative random forests to elucidate the complex genetic architecture of cardiac hypertrophy. We derive deep learning-based estimates of left ventricular mass from the cardiac MRI scans of 29,661 individuals enrolled in the UK Biobank. We report epistatic genetic variation including variants close to CCDC141, IGF1R, TTN, and TNKS. Several loci not prioritized by univariate genome-wide association analysis are identified. Functional genomic and integrative enrichment analyses reveal a complex gene regulatory network in which genes mapped from these loci share biological processes and myogenic regulatory factors. Through a network analysis of transcriptomic data from 313 explanted human hearts, we show that these interactions are preserved at the level of the cardiac transcriptome. We assess causality of epistatic effects via RNA silencing of gene-gene interactions in human induced pluripotent stem cell-derived cardiomyocytes. Finally, single-cell morphology analysis using a novel high-throughput microfluidic system shows that cardiomyocyte hypertrophy is non-additively modifiable by specific pairwise interactions between CCDC141 and both TTN and IGF1R. Our results expand the scope of genetic regulation of cardiac structure to epistasis.
ABSTRACT
CONTEXT: Inhalation of ambient fine particulate matter (PM2.5) is associated with adverse respiratory and cardiovascular effects. A major fraction of PM2.5 in urban settings is diesel exhaust particulate (DEP), and DEP-induced lung inflammation is likely a critical event mediating many of its adverse health effects. Oxidative stress has been proposed to be an important factor in PM2.5-induced lung inflammation, and the balance between pro- and antioxidants is an important regulator of this inflammation. An important intracellular antioxidant is the tripeptide thiol glutathione (GSH). Glutamate cysteine ligase (GCL) carries out the first step in GSH synthesis. In humans, relatively common genetic polymorphisms in both the catalytic (Gclc) and modifier (Gclm) subunits of GCL have been associated with increased risk for lung and cardiovascular diseases. OBJECTIVE: This study was aimed to determine the effects of Gclm expression on lung inflammation following DEP exposure in mice. MATERIALS AND METHODS: We exposed Gclm wild type, heterozygous, and null mice to DEP via intranasal instillation and assessed lung inflammation as determined by neutrophils and inflammatory cytokines in lung lavage, inflammatory cytokine mRNA levels in lung tissue, as well as total lung GSH, Gclc, and Gclm protein levels. RESULTS: The Gclm heterozygosity was associated with a significant increase in DEP-induced lung inflammation when compared to that of wild type mice. DISCUSSION AND CONCLUSION: This finding indicates that GSH synthesis can mediate DEP-induced lung inflammation and suggests that polymorphisms in Gclm may be an important factor in determining adverse health outcomes in humans following inhalation of PM2.5.
Subject(s)
Glutamate-Cysteine Ligase/metabolism , Inflammation/chemically induced , Lung Diseases/chemically induced , Lung Diseases/genetics , Particulate Matter/toxicity , Vehicle Emissions/analysis , Air Pollutants/chemistry , Air Pollutants/toxicity , Animals , Bronchoalveolar Lavage Fluid/chemistry , Gene Expression Regulation/drug effects , Gene Expression Regulation/physiology , Glutamate-Cysteine Ligase/genetics , Glutathione/chemistry , Glutathione/metabolism , Heterozygote , Inflammation/genetics , Male , Mice , Particulate Matter/chemistry , Protein SubunitsABSTRACT
The number of therapies for heart failure (HF) with reduced ejection fraction has nearly doubled in the past decade. In addition, new therapies for HF caused by hypertrophic and infiltrative disease are emerging rapidly. Indeed, we are on the verge of a new era in HF in which insights into the biology of myocardial disease can be matched to an understanding of the genetic predisposition in an individual patient to inform precision approaches to therapy. In this Review, we summarize the biology of HF, emphasizing the causal relationships between genetic contributors and traditional structure-based remodelling outcomes, and highlight the mechanisms of action of traditional and novel therapeutics. We discuss the latest advances in our understanding of both the Mendelian genetics of cardiomyopathy and the complex genetics of the clinical syndrome presenting as HF. In the phenotypic domain, we discuss applications of machine learning for the subcategorization of HF in ways that might inform rational prescribing of medications. We aim to bridge the gap between the biology of the failing heart, its diverse clinical presentations and the range of medications that we can now use to treat it. We present a roadmap for the future of precision medicine in HF.
Subject(s)
Heart Failure , Precision Medicine , Heart Failure/drug therapy , HumansABSTRACT
INTRODUCTION: The adult congenital heart disease population with repaired tetralogy of Fallot (TOF) is subject to chronic volume and pressure loading leading to a 40% probability of right ventricular (RV) failure by the 3rd decade of life. We sought to identify a non-invasive signature of adverse RV remodeling using peripheral blood microRNA (miRNA) profiling to better understand the mechanisms of RV failure. METHODS: Demographic, clinical data, and blood samples were collected from adults with repaired TOF (N = 20). RNA was isolated from the buffy coat of peripheral blood and whole genome miRNA expression was profiled using Agilent's global miRNA microarray platform. Fold change, pathway analysis, and unbiased hierarchical clustering of miRNA expression was performed and correlated to RV size and function assessed by echocardiography performed at or near the time of blood collection. RESULTS: MiRNA expression was profiled in the following groups: 1. normal RV size (N = 4), 2. mild/moderate RV enlargement (N = 11) and 3. severe RV enlargement (N = 5). 267 miRNAs were downregulated, and 66 were upregulated across the three groups (fold change >2.0, FDR corrected p<0.05) as RV enlargement increased and systolic function decreased. qPCR validation of a subset of these miRNAs identified increasing expression of miRNA 28-3p, 433-3p, and 371b-3p to be associated with increasing RV size and decreasing RV systolic function. Unbiased hierarchical clustering of all patients based on miRNA expression demonstrates three distinct patient clusters that largely coincide with progressive RV enlargement. Pathway analysis of dysregulated miRNAs demonstrates up and downregulation of cell cycle pathways, extracellular matrix proteins and fatty acid synthesis. HIF 1α signaling was downregulated while p53 signaling was predicted to be upregulated. CONCLUSION: Adults with TOF have a distinct miRNA profile with progressive RV enlargement and dysfunction implicating cell cycle dysregulation and upregulation in extracellular matrix and fatty acid metabolism. These data suggest peripheral blood miRNA can provide insight into the mechanisms of RV failure and can potentially be used for monitoring disease progression and to develop RV specific therapeutics to prevent RV failure in TOF.
Subject(s)
Circulating MicroRNA/blood , Gene Expression Regulation , Genome, Human , Heart Ventricles/physiopathology , Systole , Tetralogy of Fallot/genetics , Tetralogy of Fallot/physiopathology , Ventricular Dysfunction, Right/genetics , Adult , Circulating MicroRNA/genetics , Cluster Analysis , Down-Regulation/genetics , Echocardiography , Female , Heart Ventricles/diagnostic imaging , Heart Ventricles/pathology , Humans , Male , Middle Aged , Principal Component Analysis , Signal Transduction/genetics , Tetralogy of Fallot/blood , Tetralogy of Fallot/diagnostic imaging , Ventricular Dysfunction, Right/diagnostic imaging , Ventricular Dysfunction, Right/physiopathologySubject(s)
Liver Cirrhosis , Mitral Valve Prolapse , Mulibrey Nanism , Rare Diseases , Adult , Female , Humans , Liver Cirrhosis/diagnosis , Liver Cirrhosis/genetics , Liver Cirrhosis/therapy , Mitral Valve Prolapse/diagnosis , Mitral Valve Prolapse/genetics , Mitral Valve Prolapse/therapy , Mulibrey Nanism/diagnosis , Mulibrey Nanism/genetics , Rare Diseases/diagnosis , Rare Diseases/geneticsABSTRACT
Background: We have previously reported that in utero and early life exposure to diesel exhaust particulates predisposes mice to adult heart failure, and that in utero exposure alone is sufficient to confer this predisposition. This follow up study addresses whether neonatal exposure alone can also confer this predisposition. Methods: Newborn male C57BL/6 mice were exposed to diesel exhaust (DE) particulates immediately after birth until weaning at 21 days of age, whereupon they were transferred to filtered air (FA) conditions. At the age of 12 weeks, transverse aortic constriction (TAC) was performed followed by weekly echocardiography for three weeks. After the last echocardiogram, mice were euthanized for organ harvest, gravimetry and histology. Results: Neonatal exposure to DE particulates did not increase susceptibility to cardiac hypertrophy or heart failure after TAC when compared to FA exposed controls (ventricular weight/body weight ratio 7.505 vs. 7.517 mg/g, p = Not Significant (NS)). The left ventricular ejection fraction after TAC was similar between groups at one week, two weeks, and three weeks after procedure. Histological analysis showed no difference in the degree of cardiac hypertrophy or fibrosis. Conclusions: Neonatal exposure to DE particulates does not predispose mice to TAC-induced cardiac hypertrophy and heart failure in adulthood, in contrast to previously published results showing susceptibility due to in utero exposure.
Subject(s)
Aging , Animals, Newborn , Cardiomegaly/etiology , Heart Failure/etiology , Particulate Matter/toxicity , Vehicle Emissions/toxicity , Animals , Disease Susceptibility , Echocardiography , Follow-Up Studies , Male , Mice , Mice, Inbred C57BLABSTRACT
Exposure to fine particulate air pollution (PM2.5) is strongly associated with cardiovascular morbidity and mortality. Exposure to PM2.5 during pregnancy promotes reduced birthweight, and the associated adverse intrauterine conditions may also promote adult risk of cardiovascular disease. Here, we investigated the potential for in utero exposure to diesel exhaust (DE) air pollution, a major source of urban PM2.5, to promote adverse intrauterine conditions and influence adult susceptibility to disease. We exposed pregnant female C57Bl/6J mice to DE (≈300 µg/m³ PM2.5, 6 hrs/day, 5 days/week) from embryonic day (E) 0.5 to 17.5. At E17.5 embryos were collected for gravimetric analysis and assessed for evidence of resorption. Placental tissues underwent pathological examination to assess the extent of injury, inflammatory cell infiltration, and oxidative stress. In addition, some dams that were exposed to DE were allowed to give birth to pups and raise offspring in filtered air (FA) conditions. At 10-weeks of age, body weight and blood pressure were measured. At 12-weeks of age, cardiac function was assessed by echocardiography. Susceptibility to pressure overload-induced heart failure was then determined after transverse aortic constriction surgery. We found that in utero exposure to DE increases embryo resorption, and promotes placental hemorrhage, focal necrosis, compaction of labyrinth vascular spaces, inflammatory cell infiltration and oxidative stress. In addition, we observed that in utero DE exposure increased body weight, but counterintuitively reduced blood pressure without any changes in baseline cardiac function in adult male mice. Importantly, we observed these mice to have increased susceptibility to pressure-overload induced heart failure, suggesting this in utero exposure to DE 'reprograms' the heart to a heightened susceptibility to failure. These observations provide important data to suggest that developmental exposure to air pollution may strongly influence adult susceptibility to cardiovascular disease.
Subject(s)
Air Pollutants/adverse effects , Heart Failure/chemically induced , Maternal Exposure/adverse effects , Vehicle Emissions , Air Pollutants/analysis , Animals , Aorta/pathology , Blood Pressure , Echocardiography , Female , Inflammation , Inhalation Exposure/adverse effects , Leukocyte Common Antigens/metabolism , Male , Mice , Mice, Inbred C57BL , Myocardium/pathology , Necrosis , Oxidative Stress , Particle Size , Pregnancy , Pregnancy, Animal , Time Factors , Tyrosine/analogs & derivatives , Tyrosine/chemistry , Weight GainABSTRACT
Quantum dots (QDs) are unique semi-conductor fluorescent nanoparticles with potential uses in a variety of biomedical applications. However, concerns exist regarding their potential toxicity, specifically their capacity to induce oxidative stress and inflammation. In this study we synthesized CdSe/ZnS core/shell QDs with a tri-n-octylphosphine oxide, poly(maleic anhydride-alt-1-tetradecene) (TOPO-PMAT) coating and assessed their effects on lung inflammation in mice. Previously published in vitro data demonstrated these TOPO-PMAT QDs cause oxidative stress resulting in increased expression of antioxidant proteins, including heme oxygenase, and the glutathione (GSH) synthesis enzyme glutamate cysteine ligase (GCL). We therefore investigated the effects of these QDs in vivo in mice deficient in GSH synthesis (Gclm +/- and Gclm -/- mice). When mice were exposed via nasal instillation to a TOPO-PMAT QD dose of 6 µg cadmium (Cd) equivalents/kg body weight, neutrophil counts in bronchoalveolar lavage fluid (BALF) increased in both Gclm wild-type (+/+) and Gclm heterozygous (+/-) mice, whereas Gclm null (-/-) mice exhibited no such increase. Levels of the pro-inflammatory cytokines KC and TNFα increased in BALF from Gclm +/+ and +/- mice, but not from Gclm -/- mice. Analysis of lung Cd levels suggested that QDs were cleared more readily from the lungs of Gclm -/- mice. There was no change in matrix metalloproteinase (MMP) activity in any of the mice. However, there was a decrease in whole lung myeloperoxidase (MPO) content in Gclm -/- mice, regardless of treatment, relative to untreated Gclm +/+ mice. We conclude that in mice TOPO-PMAT QDs have in vivo pro-inflammatory properties, and the inflammatory response is dependent on GSH synthesis status. Because there is a common polymorphism in humans that influences GCLM expression, these findings imply that humans with reduced GSH synthesis capabilities may be more susceptible to the pro-inflammatory effects of QDs.