Project description:Ischemia, fibrosis, and remodeling lead to heart failure after severe myocardial infarction (MI). Myoblast sheet transplantation is a promising therapy to enhance cardiac function and induce therapeutic angiogenesis via a paracrine mechanism in this detrimental disease. We hypothesized that in a rat model of MI-induced chronic heart failure this therapy could further be improved by overexpression of the antiapoptotic, antifibrotic, and proangiogenic hepatocyte growth factor (HGF) in the myoblast sheets. We studied the ability of wild type (L6-WT) and human HGF-expressing (L6-HGF) L6 myoblast sheet-derived paracrine factors to stimulate cardiomyocyte, endothelial cell, or smooth muscle cell migration in culture. Further, we studied the autocrine effect of hHGF-expression on myoblast gene expression using microarray analysis. We induced MI in Wistar rats by left anterior descending coronary artery (LAD) ligation and allowed heart failure to develop for four weeks. Thereafter, we administered L6-WT (n=15) or L6-HGF (n=16) myoblast sheet therapy. Control rats (n=13) underwent LAD ligation and rethoracotomy without therapy and five rats underwent sham-operation in both surgeries. We evaluated cardiac function with echocardiography at 2 and 4 weeks after therapy administration. We analyzed cardiac angiogenesis and left ventricular architecture from histological sections 4 weeks after therapy. Paracrine mediators from L6-HGF myoblast sheets effectively induced migration of cardiac endothelial and smooth muscle cells but not cardiomyocytes. Microarray data revealed that hHGF-expression modulated myoblast gene expression. In vivo, L6-HGF sheet therapy effectively stimulated angiogenesis in the infarcted and non-infarcted areas. Both L6-WT and L6-HGF therapies enhanced cardiac function and inhibited remodeling in a similar fashion. In conclusion, L6-HGF therapy effectively induced angiogenesis in the chronically failing heart. Cardiac function, however, was not further enhanced by hHGF-expression. Analysis of the L6 rat skeletal myoblast cell line and myoblast cell sheets with constitutive human HGF expression.
Project description:Ischemia, fibrosis, and remodeling lead to heart failure after severe myocardial infarction (MI). Myoblast sheet transplantation is a promising therapy to enhance cardiac function and induce therapeutic angiogenesis via a paracrine mechanism in this detrimental disease. We hypothesized that in a rat model of MI-induced chronic heart failure this therapy could further be improved by overexpression of the antiapoptotic, antifibrotic, and proangiogenic hepatocyte growth factor (HGF) in the myoblast sheets. We studied the ability of wild type (L6-WT) and human HGF-expressing (L6-HGF) L6 myoblast sheet-derived paracrine factors to stimulate cardiomyocyte, endothelial cell, or smooth muscle cell migration in culture. Further, we studied the autocrine effect of hHGF-expression on myoblast gene expression using microarray analysis. We induced MI in Wistar rats by left anterior descending coronary artery (LAD) ligation and allowed heart failure to develop for four weeks. Thereafter, we administered L6-WT (n=15) or L6-HGF (n=16) myoblast sheet therapy. Control rats (n=13) underwent LAD ligation and rethoracotomy without therapy and five rats underwent sham-operation in both surgeries. We evaluated cardiac function with echocardiography at 2 and 4 weeks after therapy administration. We analyzed cardiac angiogenesis and left ventricular architecture from histological sections 4 weeks after therapy. Paracrine mediators from L6-HGF myoblast sheets effectively induced migration of cardiac endothelial and smooth muscle cells but not cardiomyocytes. Microarray data revealed that hHGF-expression modulated myoblast gene expression. In vivo, L6-HGF sheet therapy effectively stimulated angiogenesis in the infarcted and non-infarcted areas. Both L6-WT and L6-HGF therapies enhanced cardiac function and inhibited remodeling in a similar fashion. In conclusion, L6-HGF therapy effectively induced angiogenesis in the chronically failing heart. Cardiac function, however, was not further enhanced by hHGF-expression.
Project description:Introduction: Obesity is a major risk factor associated with multiple pathological conditions including diabetes and cardiovascular disease. Endothelial dysfunction is an early predictor of obesity. However, little is known regarding how early endothelial changes trigger obesity. In the present work we report a novel endothelial-mediated mechanism essential for regulation of metabolic homeostasis, driven by c-Myc. Methods: We used conditional overexpression (EC-Myc OE) mouse models to investigate the role of endothelial-specific c-Myc in metabolic homeostasis during high-fat diet exposure. Body weight, metabolic parameters and cardiovascular function were collected over time and tissue samples collected at endpoint for biochemical, pathology and RNA-sequencing analysis. Results: In the present study we demonstrate that Overexpression of endothelial c-Myc attenuated diet-induced obesity and visceral fat accumulation and prevented the development of glucose tolerance and cardiac dysfunction. Transcriptome analysis of skeletal muscle suggests that the protective effects promoted by endothelial c-Myc overexpression are associated with the expression of genes known to increase weight loss, energy expenditure and glucose tolerance. Discussion: Our results show a novel important role for endothelial c-Myc in regulating metabolic homeostasis and suggests its potential targeting in preventing obesity and associated complications such as diabetes type-2 and cardiovascular dysfunction.
Project description:TRIM24 (Tripartite Motif-Containing 24) is a key transcriptional co-regulator involved in various cellular processes, including chromatin remodeling and gene expression. However, its role in cardiomyocytes remains largely unexplored. In this study, we investigated the global proteomic changes associated with TRIM24 overexpression in neonatal rat ventricular cardiomyocytes (NRVCMs) to better understand its function in cardiac biology. NRVCMs were transduced by an Adenovirus overexpressing TRIM24. Protein isolated from the NRVCMs transduced by an Adenovirus overexpressing LacZ was used as control.
Project description:We evaluated the effects of vascular endothelial growth factor -B (VEGF-B) and the deletion of its receptor VEGFR1 from endothelial cells on cardiac hypertrophy. Whole-genome transcriptomic analysis showed that overexpression of the ligand had similar effects on the heart transcriptome as deletion of its receptor. Both treatments also induced angiogenesis and mild cardiac hypertrophy. The aim of the study was to identify pathways, which mediate angiogenesis-induced cardiac hypertrophy.