Project description:Aims: Coronary vasculature formation is a critical event during cardiac development, essential for heart function throughout perinatal and adult life. However, current understanding of coronary vascular development has largely been derived from transgenic mouse models. The aim of this study was to characterise the transcriptome of the human fetal cardiac endothelium using single-cell RNA sequencing (scRNA-seq) to provide critical new insights into the cellular heterogeneity and transcriptional dynamics that underpin endothelial specification within the vasculature of the developing heart. Methods and Results: We acquired scRNA-seq data of over 10,000 fetal cardiac endothelial cells (EC), revealing divergent EC subtypes including endocardial, capillary, venous, arterial, and lymphatic populations. Gene regulatory network analyses predicted roles for SMAD1 and MECOM in determining the identity of capillary and arterial populations, respectively. Trajectory inference analysis suggested an endocardial contribution to the coronary vasculature and subsequent arterialisation of capillary endothelium accompanied by increasing MECOM expression. Comparative analysis of equivalent data from murine cardiac development demonstrated that transcriptional signatures defining endothelial subpopulations are largely conserved between human and mouse. Furthermore, we revealed that knockdown of MECOM in human embryonic stem cell-derived EC (hESC-EC) resulted in an increase in venous EC marker expression, validating our prediction of its role in arterial EC identity. Conclusions: scRNA-seq of the human fetal cardiac endothelium identified distinct EC populations. A predicted endocardial contribution to the developing coronary vasculature was identified, as well as subsequent arterial specification of capillary EC. Loss of MECOM in hESC-EC increased venous EC marker expression, suggesting a role in maintaining arterial EC identity.
Project description:Coronaries are essential for myocardial growth and heart function. Notch is crucial for mouse embryonic angiogenesis, but its role in coronary development remains uncertain. We show Jag1, Dll4 and activated Notch1 receptor expression in sinus venosus (SV) endocardium. Endocardial Jag1 removal blocks SV capillary sprouting, while Dll4 inactivation stimulates excessive capillary growth, suggesting that ligand antagonism regulates coronary primary plexus formation. Later endothelial ligand removal, or forced expression of Dll4 or the glycosyltransferase MFng, blocks coronary plexus remodeling, arterial differentiation, and perivascular cell maturation. Endocardial deletion of Efnb2 phenocopies the coronary arterial defects of Notch mutants. Angiogenic rescue experiments in ventricular explants, or in primary human endothelial cells, indicate that EphrinB2 is a critical effector of antagonistic Dll4 and Jag1 functions in arterial morphogenesis. Thus, coronary arterial precursors are specified in the SV prior to primary coronary plexus formation and subsequent arterial differentiation depends on a Dll4-Jag1-EphrinB2 signaling cascade.
Project description:Atherosclerotic plaques tend to form in the major arteries at certain predictable locations. As these arteries vary in atherosusceptibility, inter-arterial differences in endothelial cell (EC) biology are of considerable interest. To explore the origin of differences observed between typical atheroprone and atheroresistant arteries, we used DNA microarrays to compare gene expression profiles of harvested porcine coronary (CECs) and iliac (IECs) artery ECs grown in static culture out to passage four. Fewer differences were observed between the transcriptional profiles of CECs and IECs in culture compared to in vivo, suggesting that most differences observed in vivo were due to distinct environmental cues in the two arteries. One-class significance of microarrays revealed that most in vivo interarterial differences disappeared in culture, as fold differences after passaging were not significant for 85% of genes identified as differentially expressed in vivo at a 5% false discovery rate. However, the three homeobox genes HOXA9, HOXA10, and HOXD3 remained under-expressed in coronary endothelium for all passages by at least 9, 8, and 2-fold, respectively. Continued differential expression despite removal from the in vivo environment suggests that primarily heritable or epigenetic mechanism(s) influence transcription of these three genes. Quantitative real-time polymerase chain reaction confirmed expression ratios for seven genes associated with atherogenesis and over- or under-expressed by 3-fold in CECs relative to IECs. The present study provides evidence that both local environment and vascular bed origin modulate gene expression in arterial endothelium. The transcriptional differences observed here may provide new insights into pathways responsible for coronary artery susceptibility. Endothelial cells were freshly harvested from right coronary and iliac arteries from four pigs. Cells were cultured out to passage four. RNA was isolated after each passage and expression profiles were obtained using oligo microarrays.
Project description:We show that an excess of VEGF-B protects the heart via adaptive cardiac hypertrophy and increased coronary arterial reserve, and by inducing a shift from lipid to glucose metabolism. Six VEGF-B overexpressing transgenic hearts were compared to six littermate wildtype controls
Project description:We show that an excess of VEGF-B protects the heart via adaptive cardiac hypertrophy and increased coronary arterial reserve, and by inducing a shift from lipid to glucose metabolism. Six hearts transduced with AAV-VEGF-B were compared to six AAV-HSA (human serum albumin) controls
Project description:Antiplatelet therapy is the most important treatment to reduce the risk of developing recurrent thrombosis, and to prevent progression to a complete occlusion of coronary arterial disease (CAD) patients after percutaneous coronary intervention Aim of study was to investigate the relationship between response to antiplatelet drugs and global mRNA gene expression in peripheral blood cells (PBC) in patients with coronary arterial disease (CAD)
Project description:Endothelin-1 (ET-1), an endothelium-derived vasoconstrictor peptide, plays a role in the pathophysiology of cardiovascular disease. Transgenic mice that overexpress human preproET-1 selectively in the endothelium (eET-1) exhibit endothelial dysfunction, hypertrophic remodeling and vascular inflammation of resistance-size arteries in the absence of blood pressure elevation. To understand the mechanisms whereby ET-1 induces vascular damage, vascular gene expression using DNA microarrays was employed. RNA from mesenteric arteries of female and male young (6-7 weeks) and mature (6-8 months) eET-1 and wild type (WT) mice was isolated and changes in gene expression were determined by genome-wide expression profiling using Illumina microarray. This study revealed a set of genes potentially regulated by ET-1, which might be implicated in ET-1 induced-vascular damage. Samples 1-8: Total RNA obtained from the entire mesenteric arterial tree of young (6-7 weeks) female preproendothelin-1 overexpressing mice compared to age and sex matched wild type littermate controls. Samples 9-16: Total RNA obtained from the entire mesenteric arterial tree of mature (6-8 months) female preproendothelin-1 overexpressing mice compared to age and sex matched wild type littermate controls. Samples 17-24: Total RNA obtained from the entire mesenteric arterial tree of young (6-7 weeks) male preproendothelin-1 overexpressing mice compared to age and sex matched wild type littermate controls. Samples 25-32: Total RNA obtained from the entire mesenteric arterial tree of mature (6-8 months) male preproendothelin-1 overexpressing mice compared to age and sex matched wild type littermate controls.
Project description:Across species, hematopoietic stem and progenitor cells (HSPCs) arise during embryogenesis from a specialized arterial population, termed hemogenic endothelium. Here, we describe a mechanistic role for the epigenetic regulator, Enhancer of zeste homolog-1 (Ezh1) in vertebrate HSPC production via regulation of hemogenic commitment. Loss of ezh1 in zebrafish embryos favored acquisition of hemogenic (gata2b) and HSPC (runx1) fate at the expense of the arterial program (ephrinb2a, dll4). In contrast, ezh1 overexpression blocked hematopoietic progression via maintenance of arterial gene expression. The related polycomb group subunit, Ezh2, functioned in a non-redundant, sequential manner, whereby inhibition had no impact on arterial identity, but was capable of blocking ezh1-knockdown associated HSPC expansion. Single-cell RNA-seq across ezh1 genotypes revealed a dropout of ezh1+/- cells among arterial endothelium associated with positive regulation of gene transcription. Exploitation of Ezh1/2 modulation has potential functional relevance for improving in vitro HSPC differentiation from induced pluripotent stem cell sources.
Project description:Atherosclerotic plaques tend to form in the major arteries at certain predictable locations. As these arteries vary in atherosusceptibility, inter-arterial differences in endothelial cell (EC) biology are of considerable interest. To explore the origin of differences observed between typical atheroprone and atheroresistant arteries, we used DNA microarrays to compare gene expression profiles of harvested porcine coronary (CECs) and iliac (IECs) artery ECs grown in static culture out to passage four. Fewer differences were observed between the transcriptional profiles of CECs and IECs in culture compared to in vivo, suggesting that most differences observed in vivo were due to distinct environmental cues in the two arteries. One-class significance of microarrays revealed that most in vivo interarterial differences disappeared in culture, as fold differences after passaging were not significant for 85% of genes identified as differentially expressed in vivo at a 5% false discovery rate. However, the three homeobox genes HOXA9, HOXA10, and HOXD3 remained under-expressed in coronary endothelium for all passages by at least 9, 8, and 2-fold, respectively. Continued differential expression despite removal from the in vivo environment suggests that primarily heritable or epigenetic mechanism(s) influence transcription of these three genes. Quantitative real-time polymerase chain reaction confirmed expression ratios for seven genes associated with atherogenesis and over- or under-expressed by 3-fold in CECs relative to IECs. The present study provides evidence that both local environment and vascular bed origin modulate gene expression in arterial endothelium. The transcriptional differences observed here may provide new insights into pathways responsible for coronary artery susceptibility.
Project description:Low and disturbed blood flow drives the progression of arterial diseases including atherosclerosis and aneurysms. The endothelial response to flow and its interactions with recruited platelets and leukocytes determine disease progression. Here, we report widespread changes in alternative splicing of pre-mRNA in the flow-activated murine arterial endothelium in vivo. Alternative splicing was suppressed by depletion of platelets and macrophages recruited to the arterial endothelium under low and disturbed flow. Binding motifs for the Rbfox-family are enriched adjacent to many of the regulated exons. Endothelial deletion of Rbfox2, the only family member expressed in arterial endothelium, suppresses a subset of the changes in transcription and RNA splicing induced by low flow. Our data reveal an alternative splicing program activated by Rbfox2 in the endothelium on recruitment of platelets and macrophages and demonstrate its relevance in transcriptional responses during flow-driven vascular inflammation.