[Show abstract][Hide abstract] ABSTRACT: LMNA/C mutations have been linked to the premature aging syndrome Hutchinson's progeria, dilated cardiomyopathy 1A, skeletal myopathies (such as the autosomal dominant variant of Emery-Dreifuss muscular dystrophy and limb-girdle muscular dystrophy), Charcot-Marie-Tooth disorder type 2B1, mandibuloacral dysplasia, autosomal dominant partial lipodystrophy, and axonal neuropathy. Atrioventricular block (AVB) can be associated with several cardiac disorders and it can also be a highly heritable, primitive disease. One of the most common pathologies associated with AVB is dilated cardiomyopathy (DCM), which is characterized by cardiac dilatation and reduced systolic function. In this case, onset has been correlated with several mutations in genes essential for the proper maturation of cardiomyocytes, such as the gene for lamin A/C. However, no clear genotype-phenotype relationship has been reported to date between LMNA/C mutations and cardiomyopathies.
DNA and medical histories were collected from (n = 11) members of different generations of one family, the proband of which was implanted with a pacemaker for lone, type II AVB. Exome sequencing analysis was performed on three relatives with AVB, and the mutations therein identified validated in a further three AVB-affected family members. In the initial three AVB family members, we identified 10 shared nonsynonymous single-nucleotide variations with a rare or unreported allele frequency in the 1000 Genomes Project database. Follow-up genetic screening in the additional three affected relatives disclosed a correlation between the lone AVB phenotype and the single-nucleotide polymorphism rs56816490, which generates an E317K change in lamin A/C. Although this mutation has already been described by others in a DCM-affected proband with familiarity for AVB and sudden death, the absence of DCM in our large, AVB-affected family is indicative of genotype-phenotype correlation between rs56816490 and a familial, autosomal dominant form of lone AVB.
Screening for G613A in LMNA/C in patients with lone AVB and their relatives might prevent sudden death in families affected by AVB but without familiarity for DCM. Lone AVB is an age-related disease caused by mutations in LMNA/C gene rather than a complication of DCM.
[Show abstract][Hide abstract] ABSTRACT: Ischaemic heart disease (IHD) remains the leading cause of death and disability worldwide. As a result, novel therapies are still needed to protect the heart from the detrimental effects of acute ischaemia-reperfusion injury, in order to improve clinical outcomes in IHD patients. In this regard, although a large number of novel cardioprotective therapies discovered in the research laboratory have been investigated in the clinical setting, only a few of these have been demonstrated to improve clinical outcomes. One potential reason for this lack of success may have been the failure to thoroughly assess the cardioprotective efficacy of these novel therapies in suitably designed preclinical experimental animal models. Therefore, the aim of this Position Paper by the European Society of Cardiology Working Group Cellular Biology of the Heart is to provide recommendations for improving the preclinical assessment of novel cardioprotective therapies discovered in the research laboratory, with the aim of increasing the likelihood of success in translating these new treatments into improved clinical outcomes.
Cardiovascular Research 10/2014; · 5.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Exposure to subclinical levels of lipopolysaccharide (LPS) occurs commonly and is seemingly well tolerated. However, recurrent LPS exposure induces cardiac fibrosis over 2 to 3 months in a murine model, not mediated by the renin-angiotensin system. Subclinical LPS induces cardiac fibrosis by unique mechanisms.
PLoS ONE 09/2014; 9(9):e107556. · 3.53 Impact Factor
[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; · 11.09 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; · 11.09 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; · 15.34 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; · 15.34 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.