[Show abstract][Hide abstract] ABSTRACT: The morbidity and mortality from ischemic heart disease (IHD) remain significant worldwide. The treatment for acute myocardial infarction has improved over the past decades, including early reperfusion of occluded coronary arteries. Although it is essential to re-open the artery as soon as possible, paradoxically this leads to additional myocardial injury, called acute ischemia-reperfusion injury (IRI), for which currently no effective therapy is available. Therefore, novel therapeutic strategies are required to protect the heart from acute IRI in order to reduce myocardial infarction size, preserve cardiac function and improve clinical outcomes in patients with IHD. In this review article, we will first outline the pathophysiology of acute IRI and review promising therapeutic strategies for cardioprotection. These include novel aspects of mitochondrial function, epigenetics, circadian clocks, the immune system, microvesicles, growth factors, stem cell therapy and gene therapy. We discuss the therapeutic potential of these novel cardioprotective strategies in terms of pharmacological targeting and clinical application.
[Show abstract][Hide abstract] ABSTRACT: The sympathetic nervous system plays a fundamental role in the regulation of myocardial function. During chronic pressure overload, over-activation of the sympathetic nervous system induces the release of catecholamines, which activate β-adrenergic receptors (βARs) in cardiomyocytes (CMs) and lead to increased heart rate and cardiac contractility. However, chronic stimulation of βARs leads to impaired cardiac function and β-blockers are widely used as therapeutic agents for the treatment of cardiac disease. MiR-133 is highly expressed in the myocardium and is involved in controlling cardiac function through regulation of mRNA translation/stability.
To determine whether miR-133 affects βAR signaling during progression to heart failure.
Based on bioinformatic analysis, β1AR and other components of the β1AR signal transduction cascade, including adenylate cyclase VI and the catalytic subunit of the cAMP-dependent protein kinase A (PKA), were predicted as direct targets of miR-133 and subsequently validated by experimental studies. Consistently, cAMP accumulation and activation of downstream targets were repressed by miR-133 overexpression in both neonatal and adult CMs following selective β1AR stimulation. Furthermore, gain- and loss-of-function studies of miR-133 revealed its role in counteracting the deleterious apoptotic effects caused by chronic β1AR stimulation. This was confirmed in vivo using a novel cardiac-specific TetON-miR-133 inducible transgenic mouse model (Tg133). When subjected to transaortic constriction, Tg133 mice maintained cardiac performance and showed attenuated apoptosis and reduced fibrosis compared to control mice.
MiR-133 controls multiple components of the β1AR transduction cascade and is cardioprotective during heart failure.
Circulation Research 05/2014; · 11.86 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: RATIONALE: The sympathetic nervous system plays a fundamental role in the regulation of myocardial function. During chronic pressure overload, over-activation of the sympathetic nervous system induces the release of catecholamines, which activate β-adrenergic receptors (βARs) in cardiomyocytes (CMs) and lead to increased heart rate and cardiac contractility. However, chronic stimulation of βARs leads to impaired cardiac function and β-blockers are widely used as therapeutic agents for the treatment of cardiac disease. MiR-133 is highly expressed in the myocardium and is involved in controlling cardiac function through regulation of mRNA translation/stability.
OBJECTIVE: To determine whether miR-133 affects βAR signaling during progression to heart failure.
METHODS AND RESULTS: Based on bioinformatic analysis, β1AR and other components of the β1AR signal transduction cascade, including adenylate cyclase VI and the catalytic subunit of the cAMP-dependent protein kinase A (PKA), were predicted as direct targets of miR-133 and subsequently validated by experimental studies. Consistently, cAMP accumulation and activation of downstream targets were repressed by miR-133 overexpression in both neonatal and adult CMs following selective β1AR stimulation. Furthermore, gain- and loss-of-function studies of miR-133 revealed its role in counteracting the deleterious apoptotic effects caused by chronic β1AR stimulation. This was confirmed in vivo using a novel cardiac-specific TetON-miR-133 inducible transgenic mouse model (Tg133). When subjected to transaortic constriction, Tg133 mice maintained cardiac performance and showed attenuated apoptosis and reduced fibrosis compared to control mice.
CONCLUSIONS: MiR-133 controls multiple components of the β1AR transduction cascade and is cardioprotective during heart failure.
Circulation Research 05/2014; · 11.86 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background
Peripartum cardiomyopathy (PPCM) is a pregnancy-associated cardiomyopathy in previously healthy women. Mice with a cardiomyocyte-restricted deletion of STAT3 (CKO) develop PPCM. PI3K-Akt signaling is thought to promote cardiac hypertrophy and protection during pregnancy. We evaluated the role of activated Akt-signaling in the maternal heart postpartum.
CKO mice were bred to mice harboring an Akt transgene, specifically expressed in cardiomyocytes (CAkt(tg)) generating CKO;CAkt(tg), CAkt(tg), CKO and wildtype sibling mice. CAkt(tg) and CKO;CAkt(tg) female mice developed PPCM with systolic dysfunction. Both genotypes displayed cardiac hypertrophy and lower capillary density, showed increased phosphorylation of p66SHC and FoxO3A and reduced expression of MnSOD as well as increased Cathepsin D activity and increased miR-146a levels (indicative for generation of the anti-angiogenic 16 kDa prolactin). Cardiac inflammation and fibrosis was accelerated in CKO;CAkt(tg) and associated with high postpartum mortality. The prolactin blocker, Bromocriptine, prevented heart failure and the decrease in capillary density in CKO;CAkt(tg) and in CAkt(tg) mice. Bromocriptine attenuated high mortality, up-regulation of CCL2 and cardiac inflammation as well as fibrosis in CKO;CAkt(tg). Prolactin infusion induced cardiac inflammation in CKO;CAkt(tg) independent of pregnancy. In neonatal rat cardiomyocytes, prolactin and interferon-γ (IFNγ) induced the expression of CCL2 via activation of Akt.
Postpartum Akt activation is detrimental for the peripartum heart as it lowers anti-oxidative defense and in combination with low STAT3 conditions, accelerate cardiac inflammation and fibrosis. Prolactin and its cleaved 16 kDa form are central for Akt-induced PPCM as indicated by the protection from the disease by prolactin blockade.
Cardiovascular research 01/2014; · 5.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: -The development of diagnostic tools to assess restenosis risk after stent deployment may enable the intervention to be tailored to the individual patient, for example by targeting drug-eluting stent's use to high risk patients, with the goal of improving safety and reducing costs. The CCNB1 gene (encoding cyclin B1) positively regulates cell proliferation, a key component of in-stent restenosis (ISR). We therefore hypothesized that single nucleotide polymorphisms (SNPs) in CCNB1 may serve as useful tools in risk stratification for ISR.
-We identified 3 SNPs in CCNB1 associated with increased restenosis risk in a cohort of 284 patients undergoing coronary angioplasty and stent placement (rs350099: TT vs. CC+TC, OR=1.82, 95%CI=1.09-3.03, p=0.023; rs350104: CC vs. CT+TT, OR=1.82, 95%CI=1.02-3.26, p=0.040; rs164390: GG vs. GT+TT, OR=2.27, 95%CI=1.33-3.85, p=0.002). These findings were replicated in another cohort study of 715 patients (rs350099: TT vs. CC+TC, OR=1.88, 95%CI=0.92-3.81, p=0.080; rs350104: CC vs. CT+TT, OR=2.23, 95%CI=1.18-4.25, p=0.016; rs164390: GG vs. GT+TT, OR=1.87, 95%CI=1.03-3.47, p=0.040). Moreover, the haplotype containing all three risk alleles is associated with higher CCNB1 mRNA expression in circulating lymphocytes and increased ISR risk (OR=1.43, 95%CI=1.00-1.823, p=0.039).The risk variants of rs350099, rs350104 and rs164390 are associated with increased reporter gene expression through binding of transcription factors NF-Y, AP-1 and SP1, respectively.
-Allele-dependent transcriptional regulation of CCNB1 associated with rs350099, rs350104 and rs164390 affects the risk of ISR. These findings reveal these common genetic variations as attractive diagnostic tools in risk stratification for restenosis.
[Show abstract][Hide abstract] ABSTRACT: Over the last few years, the field of microRNA (miRNA) in cardiovascular biology and disease has expanded at an incredible pace. miRNAs are themselves part of a larger family, that of non-coding RNAs, the importance of which for biological processes is starting to emerge. miRNAs are ∼22-nucleotide-long RNA sequences that can legate messenger (m)RNAs at partially complementary binding sites, and hence regulate the rate of protein synthesis by altering the stability of the targeted mRNAs. In the cardiovascular system, miRNAs have been shown to be critical regulators of development and physiology. They control basic functions in virtually all cell types relevant to the cardiovascular system (such as endothelial cells, cardiac muscle, smooth muscle, inflammatory cells, and fibroblasts) and, thus, are directly involved in the pathophysiology of many cardiovascular diseases. As a result of their role in disease, they are being studied for exploitation in diagnostics, prognostics, and therapeutics. However, there are still significant obstacles that need to be overcome before they enter the clinical arena. We present here a review of the literature and outline the directions toward their use in the clinic.
Journal of the American College of Cardiology 01/2014; · 14.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: http://www.frontiersin.org/Journal/10.3389/fphys.2014.00015/abstract
Atrial fibrillation (AF) is the most common sustained arrhythmia, especially in the elderly, and has a significant genetic component. Recently, several independent investigators have demonstrated a functional role for small non-coding RNAs (microRNAs) in the pathophysiology of this cardiac arrhythmia. This report represents a systematic and updated appraisal of the main studies that established a mechanistic association between specific microRNAs and AF, focusing both on the regulation of electrical and structural remodeling of cardiac tissue.
[Show abstract][Hide abstract] ABSTRACT: Cardiac hypertrophy, initially an adaptive response of the myocardium to stress, can progress to heart failure. The epigenetic signature underlying this phenomenon is poorly understood. Here, we report on the genome-wide distribution of seven histone modifications in adult mouse cardiomyocytes subjected to a prohypertrophy stimulus in vivo. We found a set of promoters with an epigenetic pattern that distinguishes specific functional classes of genes regulated in hypertrophy and identified 9,207 candidate active enhancers whose activity was modulated. We also analyzed the transcriptional network within which these genetic elements act to orchestrate hypertrophy gene expression, finding a role for myocyte enhancer factor (MEF)2C and MEF2A in regulating enhancers. We propose that the epigenetic landscape is a key determinant of gene expression reprogramming in cardiac hypertrophy and provide a basis for understanding the role of chromatin in regulating this phenomenon.
Proceedings of the National Academy of Sciences 11/2013; · 9.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study sought to assess the usefulness of clopidogrel-pathway genotyping and on-treatment platelet reactivity (OTR) testing in predicting major adverse cardiac events (MACE) in stable coronary artery disease (CAD) patients receiving drug-eluting stents (DES) under dual antiplatelet (clopidogrel plus aspirin) therapy.
The role of pharmacogenetics and OTR in predicting MACE-death, myocardial infarction, or stent thrombosis-in stable CAD patients scheduled for DES implantation is still debated.
Patients with stable CAD treated by DES implantation (n = 1,432) were genotyped with a TaqMan OpenArray (Applied Biosystems, Carlsbad, California) and assessed for OTR with the VerifyNow P2Y12 test (Accumetrics Inc., San Diego, California). Genes tested were ABCB1, CYP1A2, CYP2B6*9, CYP2C8*3, CYP2C9*2, CYP2C19, CYP3A4, CYP3A5*3, P2RY12, and PON1CYP2C19. High OTR was defined as P2Y12 reaction units ≥230. The endpoint at 12-month follow-up was MACE occurring during antiplatelet therapy.
All groups that were stratified for loss-of-function variants of the cytochrome P450 gene CYP2C19 had significant hazard ratios (HR) for MACE (genotypic HR: 1.41, 95% confidence interval [CI]: 1.06 to 1.89, p = 0.01; allelic HR: 1.56, 95% CI: 2.26 to 1.2, p = 0.01). Variants of other clopidogrel-pathway genes were not significantly associated with MACE. When OTR was assessed, clinical significance was found only in high-risk diabetic (HR: 2.11, 95% CI: 1.29 to 3.45, p < 0.001) and chronic kidney disease (HR: 2.03, 95% CI: 1.03 to 4.02, p = 0.04) patients.
CYP2C19 metabolizer status is an independent predictor of MACE after DES implantation and can be used for prognostication in all stable CAD patients. High OTR, as assessed by the VerifyNow P2Y12 test, is an independent predictor of MACE only for high-risk subsets, that is, patients with diabetes or chronic kidney disease.
[Show abstract][Hide abstract] ABSTRACT: To determine whether microRNAs (miRNA) involved in myocardial remodeling were differentially expresse in the blood of hypertrophic cardiomyopathy (HCM) patients, and whether circulating miRNAs correlated with the degree of left ventricular hypertrophy and fibrosis.
miRNAs-small non-coding RNAs that regulate gene expression by inhibiting RNA translation-modulate cellular function. Myocardial miRNAs modulate processes such as cardiomyocyte (CM) hypertrophy, excitation-contraction coupling, and apoptosis; non-CM-specific miRNAs regulate myocardial vascularization and fibrosis. Recently, the possibility that circulating miRNAs may be biomarkers of cardiovascular disease has been raised.
Forty-one HCM patients were characterized with conventional trans-thoracic echocardiography and cardiac magnetic resonance (CMR). Peripheral plasma levels of 21 miRNAs were assessed by quantitative real-time PCR and compared with those in a control group of 41 age- and sex-matched blood donors.
Twelve miRNAs (miR-27a, miR-199a-5p, miR-26a, miR-145, miR-133a, miR-143, miR-199a-3p, miR-126-3p, miR-29a, miR-155, miR-30a, and miR-21) were significantly increased in HCM plasma. However, only three miRNAs (miR-199a-5p, miR-27a, and miR-29a) correlated with hypertrophy; more importantly, only miR-29a correlated also with fibrosis.
Our data suggest that cardiac remodeling associated with HCM determines a significant release of miRNAs into the bloodstream: the circulating levels of both cardiac-specific and non-cardiac-specific miRNAs are significantly increased in the plasma of HCM patients. However, correlation with LV hypertrophy parameters holds true for only a few miRNAs (i.e., miR-199a-5p, miR-27a, and miR-29a), whereas only miR-29a is significantly associated with both hypertrophy and fibrosis, identifying it as a potential biomarker for myocardial remodeling assessment in HCM.
Journal of the American College of Cardiology 10/2013; · 14.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The epidemic of heart failure has stimulated interest in understanding cardiac regeneration. Evidence has been reported supporting regeneration via transplantation of multiple cell types, as well as replication of postmitotic cardiomyocytes. In addition, the adult myocardium harbors endogenous c-kit(pos) cardiac stem cells (eCSCs), whose relevance for regeneration is controversial. Here, using different rodent models of diffuse myocardial damage causing acute heart failure, we show that eCSCs restore cardiac function by regenerating lost cardiomyocytes. Ablation of the eCSC abolishes regeneration and functional recovery. The regenerative process is completely restored by replacing the ablated eCSCs with the progeny of one eCSC. eCSCs recovered from the host and recloned retain their regenerative potential in vivo and in vitro. After regeneration, selective suicide of these exogenous CSCs and their progeny abolishes regeneration, severely impairing ventricular performance. These data show that c-kit(pos) eCSCs are necessary and sufficient for the regeneration and repair of myocardial damage.
[Show abstract][Hide abstract] ABSTRACT: One the most important discoveries of the post-genomic era is that a large fraction of the genome transcribes a heterogeneous population of noncoding RNAs (ncRNA). ncRNAs shorter than 200 nucleotides are usually identified as short/small ncRNAs-examples include PIWI-interacting RNAs, small interfering RNAs, and microRNAs (miRNAs)-whereas those longer than 200 nucleotides are classified as long ncRNAs (lncRNAs). These molecules are emerging as important regulators of cellular process, such as development, differentiation, and metabolism. Not surprisingly, ncRNAs are involved also in human diseases, such as cancer and metabolic and neuronal disorders. Although the role of miRNAs is being largely investigated in cardiovascular biology, little is known about other classes of ncRNA in this field. However, recent reports have started to reveal the importance of lncRNA in heart development and suggest also an involvement in heart failure. Here, we will discuss these reports and the therapeutic potential of lncRNA for heart failure.
Journal of Cardiovascular Translational Research 07/2013; · 3.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Heart failure is a syndrome resulting from a complex genetic predisposition and multiple environmental factors, and is a leading cause of morbidity and mortality. It is frequently accompanied by changes in heart mass, size, and shape, a process known as pathological cardiac remodeling. At the molecular level, these changes are preceded and accompanied by a specific gene expression program characterized by expression of certain 'fetal' genes. This re-expression of fetal genes in the adult heart contributes to the development of the syndrome. Therefore, counteracting the gene expression changes occurring in heart failure could be a therapeutic approach for this pathology. One mechanism of gene expression regulation that has gained importance is epigenetics. This review gives an overview of the roles of some epigenetic mechanisms, such as DNA methylation, histone modifications, ATP-dependent chromatin remodeling, and microRNA-dependent mechanisms, in heart failure.
Archiv für Kreislaufforschung 07/2013; 108(4):361. · 7.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Familial dilated cardiomyopathy (DCM) is a heterogeneous disease; although 30 disease genes have been discovered, they explain only no more than half of all cases; in addition, the causes of intra-familial variability in DCM have remained largely unknown. In this study, we exploited the use of whole-exome sequencing (WES) to investigate the causes of clinical variability in an extended family with 14 affected subjects, four of whom showed particular severe manifestations of cardiomyopathy requiring heart transplantation in early adulthood. This analysis, followed by confirmative conventional sequencing, identified the mutation p.K219T in the lamin A/C gene in all 14 affected patients. An additional variant in the gene for titin, p.L4855F, was identified in the severely affected patients. The age for heart transplantation was substantially less for LMNA:p.K219T/TTN:p.L4855F double heterozygotes than that for LMNA:p.K219T single heterozygotes. Myocardial specimens of doubly heterozygote individuals showed increased nuclear length, sarcomeric disorganization, and myonuclear clustering compared with samples from single heterozygotes. In conclusion, our results show that WES can be used for the identification of causal and modifier variants in families with variable manifestations of DCM. In addition, they not only indicate that LMNA and TTN mutational status may be useful in this family for risk stratification in individuals at risk for DCM but also suggest titin as a modifier for DCM.European Journal of Human Genetics advance online publication, 6 March 2013; doi:10.1038/ejhg.2013.16.
European journal of human genetics: EJHG 03/2013; · 3.56 Impact Factor