implantation-hipsc-derived-cardiac-muscle-patches-after-myocardial

Implantation of hiPSC-derived Cardiac-muscle Patches after Myocardial Injury in a Guinea Pig Model

Due to the limited regeneration capacity of the heart in adult mammals, myocardial infarction results in an irreversible loss of cardiomyocytes. This loss ...

University Medical Center Hamburg-Eppendorf

Alterations in autophagy have been reported in hypertrophic cardiomyopathy (HCM) caused by Danon disease, Vici syndrome, or LEOPARD syndrome, but not in HCM caused by mutations in genes encoding sarcomeric proteins, which account for most of HCM cases. , encoding cMyBP-C (cardiac myosin-binding protein C), is the most frequently mutated HCM gene.

Activation of Autophagy Ameliorates Cardiomyopathy in -Targeted Knockin Mice.

Heart failure is associated with altered gene expression and DNA methylation. De novo DNA methylation is associated with gene silencing, but its role in cardiac pathology remains incompletely understood. We hypothesized that inhibition of DNA methyltransferases (DNMT) might prevent the deregulation of gene expression and the deterioration of cardiac function under pressure overload (PO). To test this hypothesis, we evaluated a DNMT inhibitor in PO in rats and analysed DNA methylation in cardiomyocytes.

Pharmacological inhibition of DNA methylation attenuates pressure overload-induced cardiac hypertrophy in rats.

The sympathetic nervous system is the main stimulator of cardiac function. While acute activation of the β-adrenoceptors exerts positive inotropic and lusitropic effects by increasing cAMP and Ca, chronically enhanced sympathetic tone with changed β-adrenergic signaling leads to alterations of gene expression and remodeling. The CREB-regulated transcription coactivator 1 (CRTC1) is activated by cAMP and Ca. In the present study, the regulation of CRTC1 in cardiomyocytes and its effect on cardiac function and growth was investigated. In cardiomyocytes, isoprenaline induced dephosphorylation, and thus activation of CRTC1, which was prevented by propranolol. Crtc1-deficient mice exhibited left ventricular dysfunction, hypertrophy and enlarged cardiomyocytes. However, isoprenaline-induced contractility of isolated trabeculae or phosphorylation of cardiac troponin I, cardiac myosin-binding protein C, phospholamban, and ryanodine receptor were not altered, suggesting that cardiac dysfunction was due to the global lack of Crtc1. The mRNA and protein levels of the Gα GTPase activating protein regulator of G-protein signaling 2 (RGS2) were lower in hearts of Crtc1-deficient mice. Chromatin immunoprecipitation and reporter gene assays showed stimulation of the Rgs2 promoter by CRTC1. In Crtc1-deficient cardiomyocytes, phosphorylation of the Gα-downstream kinase ERK was enhanced. CRTC1 content was higher in cardiac tissue from patients with aortic stenosis or hypertrophic cardiomyopathy and from two murine models mimicking these diseases. These data suggest that increased CRTC1 in maladaptive hypertrophy presents a compensatory mechanism to delay disease progression in part by enhancing Rgs2 gene transcription. Furthermore, the present study demonstrates an important role of CRTC1 in the regulation of cardiac function and growth.

Article	Year
Activation of Autophagy Ameliorates Cardiomyopathy in -Targeted Knockin Mice. Circulation. Heart failure\| PubMed ID: 29021349	2017
Pharmacological inhibition of DNA methylation attenuates pressure overload-induced cardiac hypertrophy in rats. Journal of molecular and cellular cardiology\| PubMed ID: 29792884	2018
Mechanistic role of the CREB-regulated transcription coactivator 1 in cardiac hypertrophy. Journal of molecular and cellular cardiology\| PubMed ID: 30521840	2019

Birgit Geertz

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