Project description:Recently, it was described that mammalian cells are able to eliminate those with relative lower Myc levels in the epiblast through cell competition. We have described that cardiomyocytes during heart development are also able to complete eliminating cells with lower Myc levels. We have also shown that adult cardiomyocytes respond in the same way over long periods of time when cell competition is induced by overexpressing Myc in a mosaic fashion. We therefore have developed an RNASeq assay to further understand the mechanism of elimination of WT cells and the effect of mild Myc overexpression in cardiomyocytes. Myc overexpression in a mosaic fashion in adult cardiomyocytes, 2 hearts were analyzed and two wild type littermates were used as controls
Project description:Increased COUP-TFII levels are found in human dilated cardiomyopathy as well as in mouse models that develop cardiomyopathy. COUP-TFII overexpression in adult mouse hearts caused ventricular dilation and compromised cardiac functions. To gain insights on COUP-TFII’s effect in hearts, we identified the molecular profile of COUP-TFII overexpressing hearts through microarray analysis. The result may shred light on molecular mechanisms that mediate development of dilated cardiomyopathy.
Project description:miR-133a-3p is a highly abundant cardiomyocyte-enriched microRNA whose expression is persistently decreased in response to pressure overload (or transverse aortic constriction, TAC) in mice. Overexpression of miR-133a in cardiomyocytes of mouse hearts in vivo (under the control of the Myh6 promoter) decreases pressure overload-induced apoptosis and fibrosis. In previous studies using microarray platforms, we detected numerous mRNAs whose transcript levels were altered by either or both of miR-133a overexpression and pressure overload. The data set presented here builds upon our previous study in these mice by examining mRNA-RISC associations (using Ago2-immunoprecipitated RNA) and global mRNA abundances via RNA-sequencing procedures, and tests the hypothesis that mRNAs targeted by overexpressed miR-133a are dissimilar between sham and TAC contexts. Cardiac polyadenylated RNA (mRNA) profiles were generated from nontransgenic and transgenic mouse hearts of FVB/N background, on Illumina HiSeq 2000 instruments. Male mice 8-12 weeks of age were used in these studies, and subjected to sham surgery or 1 week of pressure-overload via transverse aortic constriction (TAC). 3 nontransgenic sham, 7 transgenic sham, 5 nontransgenic TAC, 4 transgenic TAC, each with mRNA-seq and RISC-seq (mRNA-seq of Ago2 immunoprecipitate) data.
Project description:Increased COUP-TFII levels are found in human dilated cardiomyopathy as well as in mouse models that develop cardiomyopathy. COUP-TFII overexpression in adult mouse hearts caused ventricular dilation and compromised cardiac functions. To gain insights on COUP-TFII’s effect in hearts, we identified the molecular profile of COUP-TFII overexpressing hearts through microarray analysis. The result may shred light on molecular mechanisms that mediate development of dilated cardiomyopathy. We utilized a previously established CAG-S-COUP-TFII allele and crossed it with the Myh6-MerCreMer (Myh6-MCM) line to overexpress COUP-TFII specifically in cardiomyocytes at two months of age by administration of tamoxifen. The experimental group has genotype of Myh6-MCM; CAG-S-COUP-TFII while the control group consists of Myh6-MCM mice (Figure 1C). Whole ventricles were harvested 16 days post induction for molecular profiling.
Project description:This experiment aimed to investigate the transcriptional role of G4 resolvase Dhx36 in the adult mouse heart. We compared three pools of wild-type (WT) mouse hearts with three pools of Dhx36 conditional knockout (cKO) hearts. In the mutant mice, Dhx36 was conditionally deleted in cardiomyocytes using the Myh6-cre transgenic line. Each of the six pools was created using RNA extracted from 3-5 hearts from mice aged approximately 21 days. The cKO mice developed dilated cardiomyopathy and began experiencing sudden death at 40 days old, with no mutants surviving beyond 5 months.
Project description:Cardiac function of mice fed with a 60%fat diet (high fat diet, HFD) for 16 weeks was analyzed. Hearts showed an alteration in ejection fraction and an increase in left ventricular en systolic diameter. However mice injected with an AAV overexpressing microRNA-322 (miR-322) were protected: ejection fraction was less decreased and LVESD less increased than in animals treated with an AAV control or an AAVsponge anti miR-322 (which decrease miR-322 availability and action in the heart). To better understand globla changes induced by miR-322 modulation in the heart, a transcriptomic analysis was performed to compare gene expression in three hearts from HFD+AAVmiR-322 mice (showing cardiac protection) and gene expression in three hearts from HFD+AAvsponge (were miR-322 action is decreased and showing the most altered cardiac function).
Project description:We created mice, which are deficient for Myc specifically in cardiac myocytes by crossing crossed Myc-floxed mice (Mycfl/fl) and MLC-2VCre/+ mice. Serial analysis of earlier stages of gestation revealed that Myc-deficient mice died prematurely at E13.5-14.5. Morphological analyses of E13.5 Myc-null embryos showed normal ventricular size and structure; however, decreased cardiac myocyte proliferation and increased apoptosis was observed. BrdU incorporation rates were also decreased significantly in Myc-null myocardium. Myc-null mice displayed a 3.67-fold increase in apoptotic cardiomyocytes by TUNEL assay. We examined global gene expression using oligonucleotide microarrays. Numerous genes involved in mitochondrial death pathways were dysregulated including Bnip3L and Birc2. Hearts were taken from wide type and Myc-null Mouse embryos at E13.5 under the dissecting scope. Cardiac myocyte RNA was isolated using TRIZOL®Reagent Total RNA (100 ng) was hybridized to the Sentrix® MouseRef-8 Expression BeadChip that contains probes for ~24,000 transcripts. GeneChips were scanned using the Hewlett-Packard GeneArray Scanner G2500A. The data were analyzed with Illumina Inc. BeadStudio version 1.5.0.34 and normalized by rank invariant method.
Project description:A few reports have implicated specific lncRNAs in cardiac development or failure, but precise details of lncRNAs expressed in hearts and how their expression may be altered during embryonic heart development or by adult heart disease is unknown. By comparing lncRNA profiles of normal embryonic (~E14), normal adult, and hypertrophied adult hearts we defined a distinct fetal lncRNA abundance signature that includes 157 lncRNAs differentially expressed compared to adults (fold-change ≥ 50%, FDR=0.02), and which was only poorly recapitulated in hypertrophied hearts (17 differentially expressed lncRNAs; 13 of these observed in embryonic hearts). Analysis of protein-coding mRNAs from the same samples identified 22 concordantly and 11 reciprocally regulated mRNAs within 10 kb of dynamically expressed lncRNAs, reciprocal relationships of lncRNA and mRNA levels was validated for the Mccc1 and Relb genes using in vitro lncRNA knockdown in C2C12 cells. Network analysis suggested a central role for lncRNAs in modulating NFkappaB- and CREB1-regulated genes during embryonic heart growth and identified multiple mRNAs within these pathways that are also regulated, but independently of lncRNAs. Cardiac polyadenylated RNA (mRNA and lncRNA) profiles were generated from C57BL/6J mouse hearts were generated on Illumina HiSeq 2000 instruments. 7 independent E13.5 hearts, 12 adult hearts (6 at 6 weeks of age, 6 at 16 weeks of age), 4 sham-operated hearts at 12 weeks of age, and 4 hearts after 4 weeks of pressure overload (TAC) at 12 weeks of age.