Project description:The mammalian heart possesses a poor ability to regenerate after acute ischemic cardiac injury and lost cardiac muscle is replaced by scar tissue. Multiple clinical studies demonstrate that the size of scar tissue following myocardial infarction is an independent predictor of cardiovascular outcomes, yet little is known about factors that regulate the size of scar after ischemic cardiac injury. In this report, we demonstrate that collagen V, a fibrillar collagen and a minor constituent of heart scars regulates the size of heart scars after ischemic cardiac injury. Depletion of collagen V in heart scars in two independent animal models led to a significant and paradoxical increase in post infarction scar tissue size with worsening of heart function. A systems genetics approach analyzing genes versus traits across 100 in-bred strains of mice independently demonstrated that collagen V is a critical driver of post injury heart function. We show that collagen V deficiency alters the ultra-structure and mechanical properties of scar tissue that make it more vulnerable to expansion. There is altered reciprocal feedback between matrix and cells that induce expression of specific mechanosensitive integrins which drive fibroblast activation and increased ECM gene expression. Scar size increases. Administration of cilengitide, an inhibitor of specific integrins, completely rescues the phenotype of increased post injury scarring, myofibroblast formation and cardiac dysfunction in collagen V deficient mice. These observations demonstrate that collagen V, a structural constituent of heart scar tissue regulates scar size in an integrin dependent manner.
Project description:Affymetrix microarray analysis of molecular changes after myocardial infarction. Samples of heart tissue were analyzed after myocardial infarction from WT and reg3beta knock-out mice. Samples from scar tissue and samples adjacent to the scar were analyzed. In the experiment we primarily compared infarction zone of wild-type to infarction zone of knock-out animals, and remote zone of wild-type to remote zone of knock-outs.
Project description:We demonstrate an age-independent loss of type H bone endothelium in heart failure after myocardial infarction in both mice and in humans. Using single-cell RNA sequencing, we delineate the transcriptional heterogeneity of human bone marrow endothelium showing increased expression of inflammatory genes, including IL1B and MYC, in ischemic heart failure. Endothelial-specific overexpression of MYC was sufficient to induce type H bone endothelial cells, whereas inhibition of NLRP3-dependent IL-1 production partially prevents the post-myocardial infarction loss of type H vasculature in mice.
Project description:We demonstrate an age-independent loss of type H bone endothelium in heart failure after myocardial infarction in both mice and in humans. Using single-cell RNA sequencing, we delineate the transcriptional heterogeneity of human bone marrow endothelium showing increased expression of inflammatory genes, including IL1B and MYC, in ischemic heart failure. Endothelial-specific overexpression of MYC was sufficient to induce type H bone endothelial cells, whereas inhibition of NLRP3-dependent IL-1 production partially prevents the post-myocardial infarction loss of type H vasculature in mice.
Project description:We tested it in an animal model of myocardial infarction to ensure whether early initiation of dapagliflozin (DAPA), or different orders of combination with sacubitril-valsartan would result in a greater improvement of heart function than sacubitril-valsartan alone in post-myocardial infarction heart failure.
Project description:Comparison of both LncRNAs and mRNAs expression in the border zone of the myocardial infarction rats and the sham operation rats Border zone (BZ) of the myocardial infarction is critical to patients. Current treatments of myocardial infarction are primarily aimed to save the dying myocardial cell in the border zone. During myocardial infarction, certain changes in BZ, e.g, apoptosis, fibrosis, inflammation, etc, played an important role in deciding the survival. Impairment and recovery of BZ has been linked to gene expression changes. The aim of our study was to obtain a global expression profile of lncRNAs and mRNAs of the border zone in Wistar rats myocardial infarction, and identify the changes during myocardial infarction.
Project description:Sexual dimorphisms are well recognized in various cardiac diseases, including myocardial infarction (MI). MI develops later in women, but once established, it contributes more persistent symptoms and higher mortality than in men. Although mRNA-level sexual dimorphism of MI have been reported, whether miRNA transcriptome also confers such dimorphism remains unknown. Comprehensive understanding of the mRNA- and miRNA-level genetic programs underlying the heart sexual dimorphisms will expectedly improve clinical outcome by facilitating the development of gender specific treatment strategies. Here, by conducting miRNA microarray analysis of human MI samples, we set out to characterize the heart sexual dimorphisms at the level of miRNA transcriptome Human tissue samples, acquired during post-mortem examination and frozen in liquid nitrogen, were provided by the department of pathology, Tokyo Metropolitan Geriatric Hospital after the approval from the ethical committee. Age- and sex-matched cohorts were selected to compare healthy hearts to those with post-MI LV remodeling. Border zone for myocardial infarction was sampled. Total RNA was extracted using Sepasol solution (Sepasol-RNA I super G, nakalai tesque, Japan), and microarray analysis was performed using Affymetrix GeneChip® miRNA 3.0 Arrays
Project description:Alternative splicing of RNA is an underexplored area of transcriptional response. We hypothesized that early changes in alternatively spliced genes may be important for responses to cardiac injury. The goal of this study was to use high throughput sequencing to determine which genes undergo alternative splicing in the initial response to ischemia after myocardial infarction.
Project description:Myocardial infarction (MI) results from occlusion of blood supply to the heart muscle causing death of cardiac muscle cells. Following myocardial infarction (MI), scar formation acts to mechanically stabilise the injured heart to prevent rupture and death. While fibroblasts and macrophages are implicated in post-MI scar formation and maturation, their exact contributions to this process are poorly characterised, especially in the long-term (i.e., beyond 1-week post-MI). Here, we employ state-of-the-art spatially-targetted optical micro-proteomics (STOMP) to isolate proteomes of tissue fractions enriched for fibroblasts (sma+) and macrophages (cd68+) over a 6-week post-MI timecourse and compare them to whole-scar proteome. We illustrate dynamic, specific changes in sma- and cd68-enriched fraction protein composition over 1-6 weeks post-MI with some of these changes reflected in whole-infarct preparations. These results link specific cell populations to specific protein changes in whole infarct.