57 research outputs found
Ischemia and reperfusion-induced damage of the isolated mouse heart : involvement of type IIA secretory phospholipase A2
Full text linkModeling Cardiovascular Diseases with hiPSC-Derived Cardiomyocytes in 2D and 3D Cultures
Full text linkIn the last decade, the generation of cardiac disease models based on human-induced pluripotent stem cells (hiPSCs) has become of common use, providing new opportunities to overcome the lack of appropriate cardiac models. Although much progress has been made toward the generation of hiPSC-derived cardiomyocytes (hiPS-CMs), several lines of evidence indicate that two-dimensional (2D) cell culturing presents significant limitations, including hiPS-CMs immaturity and the absence of interaction between dierent cell types and the extracellular matrix. More recently, new advances in bioengineering and co-culture systems have allowed the generation of three-dimensional (3D) constructs based on hiPSC-derived cells. Within these systems, biochemical and physical stimuli influence the maturation of hiPS-CMs, which can show structural and functional properties more similar to those present in adult cardiomyocytes. In this review, we describe the latest advances in 2D- and 3D-hiPSC technology for cardiac disease mechanisms investigation, drug development, and therapeutic studies
m6A modification regulates early human cardiomyocyte lineage specification
No full textFunding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 813716. Background RNA modifications affect gene expression through the regulation of RNA metabolism. N6-methyladenosine (m6A) is the most abundant post-transcriptional modification that occurs in RNAs. Its dynamic expression is regulated by the "writer complex" (methyltransferases) and "erasers" (demethylases) and affects numerous biological functions, including mammalian embryonic stem cell (ESC) fate specification. However, the role of m6A in human cardiomyocyte (CM) lineage specification remains unclear. Purpose In this study, we aim to investigate the impact of m6A modification on early human cardiomyocyte differentiation, following the dynamic expression of m6A modification of human induced pluripotent stem cells (hiPSC) into cardiomyocytes (hiPSC-CMs). Methods hiPSCs were differentiated into hiPSC-CMs by mesodermal induction, followed by inhibition of WNT-signaling. We collected hiPSC derivates at different stages of the differentiation protocol: hiPSCs, hiPSC-derived cardiac mesoderm cells, hiPSC-derived cardiomyocyte progenitors (hiPSC-CPCs), and mature hiPSC-CMs. Protein levels of m6A key regulators were analyzed. To systematically profile the expression of m6A modification, we subjected hiPSC derivates to m6A immunoprecipitation combined with deep sequencing (MeRIP-seq) and RNA-seq. Enrichment analyses of gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway analyses were conducted to elucidate the biological significance of differentially expressed and methylated genes. Results m6A distribution analysis on hiPSC derivates revealed a conserved pattern on a transcriptome-wide level: methylation sites are mainly located nearby the stop coding regions. However, we observed upregulated levels of writer proteins during the transition of hiPSC-derived cardiac mesoderm cells into hiPSC-CPCs. Interestingly, the dynamic changes in writer protein levels toward hiPSC-CPC transition were accompanied by a higher number of significantly upregulated and hyper-methylated mRNA transcripts. GO and KEGG analyses indicated hyper-methylated upregulated transcripts are enriched in muscle cell differentiation, cardiac physiology and calcium and MAPK signaling pathways regulating heart contraction. Conclusion For the first time, our study provides evidence that m6A modification is a mediator of early human cardiomyocyte differentiation. The role of specific writer regulators and individual m6A transcripts will be further investigated
Linking cardiac mechanosensing at the sarcomere M-band, nuclear factor kappaB signaling, and cardiac remodeling
Full text linkNuclear Factor of Activated T cells (NFAT): key regulator of cardiac hypertrophy and skeletal muscle adaptation
No full textDespite significant progress in the prevention and treatment of cardiovascular diseases, heart failure is still a leading cause of morbidity and mortality in industrial countries. Sustained cardiac hypertrophy, which is defined as an increase in heart size resulting from an increase in cardiomyocyte cell volume, has been recognized as the single most important risk factor for heart failure development. Cardiac hypertrophy can be initiated by a wide array of (neuro/humoral) growth factors in response to increased workload, injury, or intrinsic defects in contractile performance. To understand the molecular determinants of the hypertrophic response and to achieve future rational drug design to treat heart failure, investigation currently focuses on identifying and characterizing intracellular signal transduction pathways in the heart. The experiments presented in this thesis focus on a signaling pathway which plays a role in the hypertrophic transcriptional response of the myocyte. This signaling route employs the Ca2+-calmodulin-dependent phosphatase calcineurin and its immediate downstream transcriptional effector Nuclear Factor of Activated T-cells (NFAT), and further focuses on the immediate downstream NFAT target genes in cardiac muscle
Heart spotting.
No full textCardiac function depends upon several factors, including adequate cellular mass, intact contractile machinery, and adequate production of ATP. An appropriate homeostasis on all these levels is crucial for the daunting life-long task the myocardium faces. Not surprisingly, many alterations in the above factors have been spotted when the heart fails and hypothesized to play a causal role in the genesis of the failing heart. Indeed, development of cardiac hypertrophy and failure is associated with chamber remodeling as well as with changes of the phenotype at the level of the individual myocyte. Disturbed energy metabolism with impaired fatty acid oxidation and lower expression of proteins involved in ATP synthesis occurs during myocardial hypertrophy and heart failure. The altered expression of proteins from metabolic pathways may reflect mitochondrial dysfunction as a feature of the transition from compensated myocardial hypertrophy with preserved fatty acid metabolism to impaired energy metabolism in heart failure
MicroRNA-199b targets the nuclear kinase Dyrk1a in an auto-amplification loop promoting calcineurin/NFAT signalling
No full textMicroRNAs (miRs) are a class of single-stranded, non-coding RNAs of about 22 nucleotides in length. Increasing evidence implicates miRs in myocardial disease processes. Here we show that miR-199b is a direct calcineurin/NFAT target gene that increases in expression in mouse and human heart failure, and targets the nuclear NFAT kinase dual-specificity tyrosine-(Y)-phosphorylation regulated kinase 1a (Dyrk1a), constituting a pathogenic feed forward mechanism that affects calcineurin-responsive gene expression. Mutant mice overexpressing miR-199b, or haploinsufficient for Dyrk1a, are sensitized to calcineurin/NFAT signalling or pressure overload and show stress-induced cardiomegaly through reduced Dyrk1a expression. In vivo inhibition of miR-199b by a specific antagomir normalized Dyrk1a expression, reduced nuclear NFAT activity and caused marked inhibition and even reversal of hypertrophy and fibrosis in mouse models of heart failure. Our results reveal that microRNAs affect cardiac cellular signalling and gene expression, and implicate miR-199b as a therapeutic target in heart failure.
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