Development of gene expression signatures of ascending aorta of the patients with bicuspid aortic valve compared to tricuspid aortic valve.
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ABSTRACT: Bicuspid aortic valve is well known as a risk factor of dilation of ascending aorta. But the mechanisms of dialation are unknown. Morever, patients with bicuspid aortic valve tend to be aortic valve disease at younger age. After aortic valve surgery, if ascending aorta is dilated, the patient must be performed re-operation. For that reason, surgery for aortic root or ascending aorta is recommended to patient with bicuspid aortic valve with dilated ascending aorta. We thought that abnormality of cell cycle of the structure protein participated in ascending aorta dilation of patient with bicuspid aortic valve. We resected the wall of the ascending aota from patient undergoing aortic valve replacement for aortic valve stenosis during operation, and performed immunohistochemical staining for akt. Anti Akt antibodys were stained much on aortic media with bicuspoed aortic valve. Akt is a protein that is involved in mTOR / PI3K, and modulate the cell differenciation and proliferation. Further, the same samples were analyzed using a microarray method. On bicuspid aortic valve patients, the expression of TSC2 is reduced, and GβL is increased. TSC2 inhibit this pathway, and MLST8 activate this pathway. In the ascending aorta of BAV patients, PI3K / mTOR system is considered to be activated. When this pathway is activated, cell proliferation and cytodifferentiation are promoted abnormally,
Project description:Genome wide DNA methylation profiling of ascending aorta tissue samples from normal, aortic dissection and bicuspid aortic valve patients with aortic dilation. The Illumina Infinium 450k Human DNA methylation Beadchip was used to obtain DNA methylation profiles across more than 450,000 CpGs in ascending aorta samples. Samples included 6 normal donors, 12 patients with aortic dissection and 6 patients with bicuspid aortic valve and dilated aorta.
Project description:Patients with bicuspid aortic valve (BAV) have increased risk of thoracic ascending aortic aneurysm (AscAA) and dissection compared to those with a normal tricuspid aortic valve (TAV). The present study was undertaken to evaluate whether differences in gene expression exist in aortas from BAV and TAV patients with AscAA. Experiment Overall Design: Aneurysmal tissue of ascending aorta was collected from 13 patients with bicuspid aortic valve (BAV) and 12 patients with tricuspid aortic valve (TAV). Patients were selected on the basis of aortic diameter, age and other disease conditions. Patients with giant cell aortitis, cardiovascular abnormalities, inherited connective tissue disorders such as Marfan and Ehlers-Danlos syndrome were excluded from the study. RNA was extracted using Invitrogen RNA extraction kit and shown to be of adequate quality before application to Affymetrix microarray U133A gene chips probing for over 16,000 genes per chip. Two different methods of data analysis were performed: a linear model and GeneSpring.
Project description:BACKGROUND: The vast majority of thoracic aortic aneurysms (TAAs) are observed either together with a bicuspid aortic valve (BAV), a common congenital disorder, or in idiopathic cases such as patients with a normal tricuspid aortic valve (TAV). The main objective of our study was to identify shared and unique gene expression properties underlying the aortic dilation of BAV and TAV patients. METHODS AND RESULTS: Tissue biopsies for RNA and histological analyses were obtained from aorta of non-dilated (<40mm) and dilated (>45mm) aorta of BAV and TAV patients (in total 131 patients). Additional controls were from mammary artery of the same patients (n=88) and aorta from transplant donors (n=13). Gene expression profiles generated using Affymetrix Exon arrays were analyzed from controls and from aorta intima-media and adventitia of patients (in total 345 samples). 606 genes in aortic intima-media were found to be differentially expressed with dilation. Of these, only few (<4%) were differentially expressed in both BAV and TAV patients. Gene set enrichment analysis identified cell adhesion and extracellular region gene ontology sets as common features of TAA in BAV and TAV patients. The set of immune response genes was observed to be particularly overexpressed in aortic media of dilated TAV samples. CONCLUSION: The divergent gene expression profiles indicate fundamental differences in TAA etiology of BAV and TAV patients. Immune response activation solely in the aorta media of TAV patients suggests that inflammation is a causal factor of TAA in this patient group. Biobank of patient material. Each tissue sample is from a different patient as indicated by patient ID.
Project description:Ascending aortic aneurysms (AscAA) are a life-threatening disease whose molecular basis is poorly understood. Mutations in NOTCH1 have been linked to bicuspid aortic valve (BAV), which is associated with AscAA. Here, we describe a novel role for Notch1 in AscAA. We found that Notch1 haploinsufficiency exacerbated the aneurysmal aortic root dilation seen in the Marfan syndrome mouse model and that heterozygous deletion of Notch1 in the second heart field (SHF) lineage recapitulated this exacerbated phenotype. Lineage tracing analysis showed that loss of Notch1 in the SHF reduces the number of SHF-derived smooth muscle cells in the aortic root, and RNA-seq analysis demonstrated distinct in vivo expression patterns between lineage-specific regions of the ascending aorta. Finally, Notch1+/- mice in a predominantly 129S6 background develop aortic root dilation, indicating that loss of Notch1 independently predisposes to AscAA. These findings are the first to demonstrate a SHF lineage-specific role for Notch1 in AscAA and suggest that genes linked to the development of BAV may also contribute to the associated aortopathy.
Project description:<p>Turner syndrome is a disorder affecting only girls and women, which is caused by a complete or partial loss of the second sex chromosome. Girls and women with Turner syndrome have a variety of phenotypes. Of interest to this study is aortopathy, including bicuspid aortic valve (BAV) and thoracic aortic dilation (TAD) in which we know that 25 - 50% of girls with Turner syndrome are born with.</p> <p>The aorta is the main artery that conducts the blood out of the heart. The aortic valve guards the entrance to the aorta. When the aortic valve has two leaflets instead of the usual three it is called a BAV. BAV is more common than all other congenital heart defects combined. BAV commonly causes obstructions to blood flow out of the heart or become leaky over time. BAV often occurs in combination with TAD. In Turner syndrome, TADs are increased 50-100 fold compared to the general population. Currently, there are no effective approaches or pre-surgical treatments for aortic disease. Therefore, progression of aortic disease in individuals with BAV/TAD can result in catastrophic aortic dissection, rupture, and death. </p> <p>Our goal is to leverage DNA sequencing and carefully curated patient samples to gain a better understanding of the molecular mechanisms that cause these inter-related aortic diseases. </p>
Project description:Located at the junction of left ventricle and ascending aorta, aortic root is a central cardiovascular structure consisting of aortic valve and coronary ostium that are essential for systemic and coronary circulation, respectively. Malformations of aortic valve and coronary ostium are common birth defects and may occur together in human patients, leading to complex complications including aortic valve stenosis, myocardial ischemia, heart failure and sudden cardiac death. Despite of their physiological and clinical significances, the developmental and molecular mechanisms by which coordinate the formation of aortic valve and coronary ostium remain poorly understood. Here we report that SOX17 (SRY-box 17) is an essential transcription factor required for the maturation of aortic root, as well as the patterning of aortic valve and coronary ostium. We show in mouse that deletion of Sox17 in the aortic root endothelium results in defective aortic valve with underdeveloped non-coronary leaflet (NCL) or bicuspid aortic valve (BAV) without NCL. The valve defects are accompanied by misplaced left coronary ostium that reduces coronary blood flow, leading to myocardial hypoxia and death of embryos. Mechanistically, deletion of Sox17 decreases the expression of Pdgfb (Platelet derived growth factor, B polypeptide) in the aortic root endothelium and the PDGF growth signaling in the NCL mesenchyme and aortic root smooth muscle, both of which are derived from the second heart field (SHF) cardiomyocyte precursors. Furthermore, the deletion upregulates the expression of Ctgf (Connective tissue growth factor) and the extracellular matrix (ECM) genes, whereas downregulates the vascular smooth muscle genes, in the forming aortic root. Together, these findings support a developmental disease mechanism in which delayed growth and maturation of aortic root, due to lack of SOX17-PDGF/CTGF signaling, contributes to BAV and CAAs, two common congenital cardiovascular defects.
Project description:BACKGROUND: The vast majority of thoracic aortic aneurysms (TAAs) are observed either together with a bicuspid aortic valve (BAV), a common congenital disorder, or in idiopathic cases such as patients with a normal tricuspid aortic valve (TAV). The main objective of our study was to identify shared and unique gene expression properties underlying the aortic dilation of BAV and TAV patients. METHODS AND RESULTS: Tissue biopsies for RNA and histological analyses were obtained from aorta of non-dilated (<40mm) and dilated (>45mm) aorta of BAV and TAV patients (in total 131 patients). Additional controls were from mammary artery of the same patients (n=88) and aorta from transplant donors (n=13). Gene expression profiles generated using Affymetrix Exon arrays were analyzed from controls and from aorta intima-media and adventitia of patients (in total 345 samples). 606 genes in aortic intima-media were found to be differentially expressed with dilation. Of these, only few (<4%) were differentially expressed in both BAV and TAV patients. Gene set enrichment analysis identified cell adhesion and extracellular region gene ontology sets as common features of TAA in BAV and TAV patients. The set of immune response genes was observed to be particularly overexpressed in aortic media of dilated TAV samples. CONCLUSION: The divergent gene expression profiles indicate fundamental differences in TAA etiology of BAV and TAV patients. Immune response activation solely in the aorta media of TAV patients suggests that inflammation is a causal factor of TAA in this patient group.
Project description:Patients with bicuspid aortic valve (BAV) have increased risk of thoracic ascending aortic aneurysm (AscAA) and dissection compared to those with a normal tricuspid aortic valve (TAV). The present study was undertaken to evaluate whether differences in gene expression exist in aortas from BAV and TAV patients with AscAA. Keywords: disease state analysis
Project description:Bicuspid aortic valve (BAV) is a common congenital cardiac anomaly, with an estimated incidence of 1-2%. It is responsible for the greatest burden of aortic valve disease in patients younger than 70 years in North America. We performed microRNA profiling in end-stage valve leaflets with BAV and TAV. Patients undergoing elective aortic valve replacement for aortic stenosis at St. Michael’s Hospital, University of Toronto, between June 2010 and June 2011 were enrolled. Aortic valve leaflets were obtained intraoperatively from patients with congenital bicuspid (BAV; N=10) and tricuspid aortic valves (TAV; N=10) at the time of valve replacement. Leaflets were flash frozen in liquid nitrogen. MiRNA was isolated using the miRNeasy kit (Qiagen, Hilden, Germany) according to the manufacturer`s instructions. For miRNA microarray analysis, total RNA was directly labeled with biotin and hybridized to the GenoExplorer microRNA human array containing 1583 human miRNA probes (Genosensor, Tempe, AZ) and the fluorescent signals were then scanned using a GenePix 4000b Biochip. The average of 3 mean fluorescence signal intensities for each miRNA probe was normalized to that for tRNAmet. Precursor miRNAs detected at 2-fold greater than background were considered to be expressed. Data were analyzed with GenePix 5.0 software, provided by GenoSensor Corp.
Project description:Elastin wild type Eln+/+ and Eln+/- mouse aorta and aortic valve tissue. In the study, we demonstrated differential gene expression in juvenile elastin deficient mouse valve tissue. In the study, we hybridized RNA from Elastin wild type (Eln+/+) aorta tissue, elastin wild type (Eln+/+) aortic valve tissue, elastin (Eln+/-) aorta tissue and elastin (Eln+/-) aortic valve tissue to Affymetrix GeneChip Mouse Genome 430 2.0 Array