Calcium Upregulation by Percutaneous Administration of Gene Therapy in Cardiac Disease (CUPID): a phase 2 trial of intracoronary gene therapy of sarcoplasmic reticulum Ca2+-ATPase in patients with advanced heart failure

Adeno-Associated Virus Gene Therapy: Translational Progress and Future Prospects in the Treatment of Heart Failure

Despite advances in treatment over the past decade, heart failure remains a significant public health burden and a leading cause of death in the developed world. Gene therapy provides a promising approach for preventing and reversing cardiac abnormalities, however, clinical application has shown limited success to date. A substantial effort is being invested into the development of recombinant adeno-associated viruses (AAVs) for cardiac gene therapy as AAV gene therapy offers a high safety profile and provides sustained and efficient transgene expression following a once-off administration. Due to the physiological, anatomical and genetic similarities between large animals and humans, preclinical studies using large animal models for AAV gene therapy are crucial stepping stones between the laboratory and the clinic. Many molecular targets selected to treat heart failure using AAV gene therapy have been chosen because of their potential to regulate and restore cardiac contractility. Other genes targeted with AAV are involved with regulating angiogenesis, beta-adrenergic sensitivity, inflammation, physiological signalling and metabolism. While significant progress continues to be made in the field of AAV cardiac gene therapy, challenges remain in overcoming host neutralising antibodies, improving AAV vector cardiac-transduction efficiency and selectivity, and optimising the dose, route and method of delivery.

Non-invasive detection of adeno-associated viral gene transfer using a genetically encoded CEST-MRI reporter gene in the murine heart

Research into gene therapy for heart failure has gained renewed interest as a result of improved safety and availability of adeno-associated viral vectors (AAV). While magnetic resonance imaging (MRI) is standard for functional assessment of gene therapy outcomes, quantitation of gene transfer/expression relies upon tissue biopsy, fluorescence or nuclear imaging. Imaging of gene expression through the use of genetically encoded chemical exchange saturation transfer (CEST)-MRI reporter genes could be combined with clinical cardiac MRI methods to comprehensively probe therapeutic gene expression and subsequent outcomes. The CEST-MRI reporter gene Lysine Rich Protein (LRP) was cloned into an AAV9 vector and either administered systemically via tail vein injection or directly injected into the left ventricular free wall of mice. Longitudinal in vivo CEST-MRI performed at days 15 and 45 after direct injection or at 1, 60 and 90 days after systemic injection revealed robust CEST contrast in myocardium that was later confirmed to express LRP by immunostaining. Ventricular structure and function were not impacted by expression of LRP in either study arm. The ability to quantify and link therapeutic gene expression to functional outcomes can provide rich data for further development of gene therapy for heart failure.

New insights into SERCA2a gene therapy in heart failure: pay attention to the negative effects of B-type natriuretic peptides

Sarcoplasmic/endoplasmic reticulum calcium ATPase 2a (SERCA2a) is a target of interest in gene therapy for heart failure with reduced ejection fraction (HFrEF). However, the results of an important clinical study, the Calcium Upregulation by Percutaneous Administration of Gene Therapy in Cardiac Disease (CUPID) trial, were controversial. Promising results were observed in the CUPID 1 trial, but the results of the CUPID 2 trial were negative. The factors that caused the controversial results remain unclear. Importantly, enrolled patients were required to have a higher plasma level of B-type natriuretic peptide (BNP) in the CUPID 2 trial. Moreover, BNP was shown to inhibit SERCA2a expression. Therefore, it is possible that high BNP levels interact with treatment effects of SERCA2a gene transfer and accordingly lead to negative results of CUPID 2 trial. From this point of view, effects of SERCA2a gene therapy should be explored in heart failure with preserved ejection fraction, which is characterised by lower BNP levels compared with HFrEF. In this review, we summarise the current knowledge of SERCA2a gene therapy for heart failure, analyse potential interaction between BNP levels and therapeutic effects of SERCA2a gene transfer and provide directions for future research to solve the identified problems.

Pathophysiological mechanism and therapeutic role of S100 proteins in cardiac failure: a systematic review

S100 proteins are a family of highly acidic calcium-binding proteins involved in calcium handling in many tissues and organs. Some of these proteins are highly expressed in cardiac tissue, and an impairment of some specific S100 proteins has been related to heart failure. To check this hypothesis, we decided to review the literature since 2008 until May 2015. According to the studies collected, recovering S100A1 levels may enhance contractile/relaxing performance in heart failure, reverse negative force-frequency relationship, improve contractile reserve, reverse diastolic dysfunction and protect against pro-arrhythmic reductions of sarcoplasmic reticulum calcium. The safety profile of gene therapy was also confirmed. Increased S100B protein levels were related to a worse outcome in chronic heart failure. S100A8/A9 complex plasma levels, as well as other inflammatory biomarkers, were significantly higher in chronic heart failure patients. S100A2 seems to increase both contractile and relaxation performance in animal cardiomyocytes. Otherwise, S100A6 cardiac expression seems to have no effects on contractility. S100A4 KO mice showed reduced cardiac interstitial fibrosis. Data collected encourage a potential prospective application in human. These proteins could be exploited as biomarkers in stadiation and prognosis of chronic heart failure, as well as therapeutic target to rescue failing heart. Registration details The study protocol has been registered in PROSPERO ( http://www.crd.york.ac.uk/PROSPERO/ ) under registration number CRD42015027932.

Intramyocardial injection of SERCA2a-expressing lentivirus improves myocardial function in doxorubicin-induced heart failure

BACKGROUND

Doxorubicin is an effective anticancer drug. The major limitation to its use is the induction of dose-dependent cardiomyopathy. No specific treatment exists for doxorubicin-induced cardiomyopathy and treatments used for other forms of heart failure have only limited beneficial effects. The contraction-relaxation cycle of the heart is controlled by cytosolic calcium concentrations, which, in turn, are critically regulated by the activity of the sarcoplasmic reticulum Ca(2) (+) ATPase (SERCA2a) pump. We hypothesized that SERCA2a gene transfer would ameliorate doxorubicin-induced cardiomyopathy.

METHODS

Lentiviral vectors LV-SERCA2a-GFP and LV-GFP were constructed and in vitro gene transfer of LV-SERCA2a-GFP confirmed SERCA2a expression by western blot analysis. Heart failure was induced by giving a single intraperitoneal injection of doxorubicin. LV-SERCA2a-GFP, LV-GFP vectors and phosphate-buffered saline (PBS) were injected under echocardiographic control to the anterior wall of the left ventricle.

RESULTS

Echocardiography analyses were performed on the injection day and 28 days postinjection. On the injection day, there were no significant differences in the average ejection fractions (EFs) among SERCA2a (40.0%), GFP (41.1%) and PBS (39.4%) injected animals. On day 28, EF in the SERCA2a group had increased by 16.6 ± 6.7% to 46.4 ± 2.1%. By contrast, EFs in the GFP (40.2 ± 1.3%) and PBS (40.6 ± 1.4%) groups remained at pre-injection levels. In addition, end systolic and end diastolic left ventricle volumes were significantly smaller in the SERCA2a group compared to controls.

CONCLUSIONS

SERCA2a gene transfer significantly improves left ventricle function and dimensions in doxorubicin-induced cardiomyopathy, thus making LV-SERCA2a gene transfer an attractive treatment modality for doxorubicin-induced heart failure. Copyright © 2016 John Wiley & Sons, Ltd.

Fusion of Anthopleurin-B to AAV2 increases specificity of cardiac gene transfer

AAV-mediated gene therapy has become a promising therapeutic strategy for chronic diseases. Its clinical utilization, however, is limited by the potential risk of off-target effects. In this work we attempt to overcome this challenge, hypothesizing that cardiac ion channel-specific ligands could be fused onto the AAV capsid, and narrow its tropism to cardiac myocytes. We successfully fused the cardiac sodium channel (Na_v1.5)-binding toxin Anthopleurin-B onto the AAV2 capsid without compromising virus integrity, and demonstrated increased specificity of cardiomyocyte attachment. Although virus attachment to Na_v1.5 did not supersede the natural heparan-mediated virus binding, heparan-binding ablated vectors carrying Anthopleurin-B eliminated hepatic and other extracardiac gene transfer, while preserving cardiac myocyte gene transfer. Virus binding to the cardiac sodium channel transiently decreased sodium current density, but did not cause any arrhythmias. Our findings expand the knowledge of attachment, infectivity, and intracellular processing of AAV vectors, and present an alternative strategy for vector retargeting.

miR-25 Tough Decoy Enhances Cardiac Function in Heart Failure

MicroRNAs are promising therapeutic targets, because their inhibition has the potential to normalize gene expression in diseased states. Recently, our group found that miR-25 is a key SERCA2a regulating microRNA, and we showed that multiple injections of antagomirs against miR-25 enhance cardiac contractility and function through SERCA2a restoration in a murine heart failure model. However, for clinical application, a more stable suppressor of miR-25 would be desirable. Tough Decoy (TuD) inhibitors are emerging as a highly effective method for microRNA inhibition due to their resistance to endonucleolytic degradation, high miRNA binding affinity, and efficient delivery. We generated a miR-25 TuD inhibitor and subcloned it into a cardiotropic AAV9 vector to evaluate its efficacy. The AAV9 TuD showed selective inhibition of miR-25 in vitro cardiomyoblast culture. In vivo, AAV9-miR-25 TuD delivered to the murine pressure-overload heart failure model selectively decreased expression of miR-25, increased levels of SERCA2a protein, and ameliorated cardiac dysfunction and fibrosis. Our data indicate that miR-25 TuD is an effective long-term suppressor of miR-25 and a promising therapeutic candidate to treat heart failure.

Therapeutic Benefit and Gene Network Regulation by Combined Gene Transfer of Apelin, FGF2, and SERCA2a into Ischemic Heart

Despite considerable advances in cardiovascular disease treatment, heart failure remains a public health challenge. In this context, gene therapy appears as an attractive approach, but clinical trials using single therapeutic molecules result in moderate benefit. With the objective of improving ischemic heart failure therapy, we designed a combined treatment, aimed to simultaneously stimulate angiogenesis, prevent cardiac remodeling, and restore contractile function. We have previously validated IRES-based vectors as powerful tools to co-express genes of interest. Mono- and multicistronic lentivectors expressing fibroblast growth factor 2 (angiogenesis), apelin (cardioprotection), and/or SERCA2a (contractile function) were produced and administrated by intramyocardial injection into a mouse model of myocardial infarction. Data reveal that combined treatment simultaneously improves vessel number, heart function parameters, and fibrosis prevention, due to FGF2, SERCA2a, and apelin, respectively. Furthermore, addition of SERCA2a in the combination decreases cardiomyocyte hypertrophy. Large-scale transcriptome analysis reveals that the triple treatment is the most efficient in restoring angiogenic balance as well as expression of genes involved in cardiac function and remodeling. Our study validates the concept of combined treatment of ischemic heart disease with apelin, FGF2, and SERCA2a and shows that such therapeutic benefit is mediated by a more effective recovery of gene network regulation.

Strategy to detect pre-existing immunity to AAV gene therapy

Gene therapy may offer a new treatment option, particularly for patients with severe hemophilia, based on recent research. However, individuals with pre-existing immunity to adeno-associated viruses (AAVs) may be less likely to benefit from AAV vector-based therapies. To study pre-existing AAV5 immunity in humans, we validated two complementary, sensitive, and scalable in vitro assays to detect AAV5 total antibodies and transduction inhibition (TI). Using these two assays, we found that 53% of samples from 100 healthy male individuals were negative in both assays, 18% were positive in both assays, 5% were positive for total antibodies but negative for TI and, of interest, 24% were negative for total antibodies but positive for TI activity, suggesting the presence of non-antibody-based neutralizing factors in human plasma. Similar findings were obtained with 24 samples from individuals with hemophilia A. On the basis of these results, we describe the development of a dual-assay strategy to identify individuals without total AAV5 antibodies or neutralizing factors who may be more likely to respond to AAV5-directed gene therapy. These assays offer a universal, transferrable platform across laboratories to assess the global prevalence of AAV5 antibodies and neutralizing factors in large patient populations to help inform clinical development strategies.

A Double-Blind, Randomized, Placebo-Controlled Clinical Study of Trofinetide in the Treatment of Rett Syndrome

BACKGROUND

This study aimed to determine the safety and tolerability of trofinetide and to evaluate efficacy measures in adolescent and adult females with Rett syndrome, a serious and debilitating neurodevelopmental condition for which no therapies are available for its core features.

METHODS

This was an exploratory, phase 2, multicenter, double-blind, placebo-controlled, dose-escalation study of the safety and tolerability of trofinetide in 56 adolescent and adult females with Rett syndrome. Subjects were randomly assigned in a 2:1 ratio to 35 mg/kg twice daily of trofinetide or placebo for 14 days; 35 mg/kg twice daily or placebo for 28 days; or 70 mg/kg twice daily or placebo for 28 days. Safety assessments included adverse events, clinical laboratory tests, vital signs, electrocardiograms, physical examinations, and concomitant medications. Efficacy measurements were categorized into four efficacy domains, which related to clinically relevant, phenotypic dimensions of impairment associated with Rett syndrome.

RESULTS

Both 35 mg/kg and 70 mg/kg dose levels of trofinetide were well tolerated and generally safe. Trofinetide at 70 mg/kg demonstrated efficacy compared with placebo based on prespecified criteria.

CONCLUSION

Trofinetide was well tolerated in adolescent and adult females with Rett syndrome. Although this study had a relatively short duration in a small number of subjects with an advanced stage of disease, consistent efficacy trends at the higher dose were observed in several outcome measures that assess important dimensions of Rett syndrome. These results represented clinically meaningful improvement from the perspective of the clinicians as well as the caregivers.

Regulatory and Scientific Advancements in Gene Therapy: State-of-the-Art of Clinical Applications and of the Supporting European Regulatory Framework

Advanced therapy medicinal products (ATMPs) have a massive potential to address existing unmet medical needs. Specifically, gene therapy medicinal products (GTMPs) may potentially provide cure for several genetic diseases. In Europe, the ATMP regulation was fully implemented in 2009 and, at this point, the Committee for Advanced Therapies was created as a dedicated group of specialists to evaluate medicinal products requiring specific expertise in this area. To date, there are three authorized GTMPs, and the first one was approved in 2012. Broad research has been conducted in this field over the last few decades and different clinical applications are being investigated worldwide, using different strategies that range from direct gene replacement or addition to more complex pathways such as specific gene editing or RNA targeting. Important safety risks, limited efficacy, manufacturing hurdles, or ethical conflicts may represent challenges in the success of a candidate GTMP. During the development process, it is fundamental to take such aspects into account and establish overcoming strategies. This article reviews the current European legal framework of ATMPs, provides an overview of the clinical applications for approved and investigational GTMPs, and discusses critical challenges in the development of GTMPs.

Long non-coding RNAs in the atherosclerotic plaque

BACKGROUND AND AIMS

Genetic and environmental factors are important components of the development of atherosclerosis. Long non-coding RNA (lncRNAs) have emerged as regulators of multiple pathophysiological pathways in the cardiovascular system. Here, we investigated potential associations between lncRNAs and atherosclerosis.

METHODS

Tissue samples from atherosclerotic coronary artery plaques and non-atherosclerotic internal mammary artery were obtained from 20 patients during coronary artery bypass surgery. Expression levels of five lncRNAs known to be associated with coronary artery disease were measured using quantitative PCR.

RESULTS

Cyclin-dependent kinase inhibitor 2B antisense RNA 1 (ANRIL) and myocardial infarction-associated transcript (MIAT) were more expressed in the atherosclerotic arteries compared to the non-atherosclerotic arteries. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) was less expressed in the atherosclerotic plaques. Expression levels of potassium voltage-gated channel, KQT-like subfamily, member 1 opposite strand/antisense transcript 1 (KCNQ1OT1) and hypoxia inducible factor 1A antisense RNA 2 (aHIF) were comparable between atherosclerotic and non-atherosclerotic arteries. In the atherosclerotic plaque, expression levels of MALAT1, MIAT, KCNQ1OT1 and aHIF were inversely correlated with age.

CONCLUSIONS

We report significant associations between lncRNAs and atherosclerosis. These findings support a role for lncRNAs in coronary artery disease development.

Protein Phosphatase Inhibitor-1 Gene Therapy in a Swine Model of Nonischemic Heart Failure

BACKGROUND

Increased protein phosphatase-1 in heart failure (HF) induces molecular changes deleterious to the cardiac cell. Inhibiting protein phosphatase-1 through the overexpression of a constitutively active inhibitor-1 (I-1c) has been shown to reverse cardiac dysfunction in a model of ischemic HF.

OBJECTIVES

This study sought to determine the therapeutic efficacy of a re-engineered adenoassociated viral vector carrying I-1c (BNP116.I-1c) in a preclinical model of nonischemic HF, and to assess thoroughly the safety of BNP116.I-1c gene therapy.

METHODS

Volume-overload HF was created in Yorkshire swine by inducing severe mitral regurgitation. One month after mitral regurgitation induction, pigs were randomized to intracoronary delivery of either BNP116.I-1c (n = 6) or saline (n = 7). Therapeutic efficacy and safety were evaluated 2 months after gene delivery. Additionally, 24 naive pigs received different doses of BNP116.I-1c for safety evaluation.

RESULTS

At 1 month after mitral regurgitation induction, pigs developed HF as evidenced by increased left ventricular end-diastolic pressure and left ventricular volume indexes. Treatment with BNP116.I-1c resulted in improved left ventricular ejection fraction (-5.9 ± 4.2% vs. 5.5 ± 4.0%; p < 0.001) and adjusted dP/dt maximum (-3.39 ± 2.44 s^-1 vs. 1.30 ± 2.39 s^-1; p = 0.007). Moreover, BNP116.I-1c-treated pigs also exhibited a significant increase in left atrial ejection fraction at 2 months after gene delivery (-4.3 ± 3.1% vs. 7.5 ± 3.1%; p = 0.02). In vitro I-1c gene transfer in isolated left atrial myocytes from both pigs and rats increased calcium transient amplitude, consistent with its positive impact on left atrial contraction. We found no evidence of adverse electrical remodeling, arrhythmogenicity, activation of a cellular immune response, or off-target organ damage by BNP116.I-1c gene therapy in pigs.

CONCLUSIONS

Intracoronary delivery of BNP116.I-1c was safe and improved contractility of the left ventricle and atrium in a large animal model of nonischemic HF.

Foreword

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Heart failure with reduced ejection fraction

Heart failure is a global public health problem that affects more than 26 million people worldwide. The global burden of heart failure is growing and is expected to increase substantially with the ageing of the population. Heart failure with reduced ejection fraction accounts for approximately 50% of all cases of heart failure in the United States and is associated with substantial morbidity and reduced quality of life. Several diseases, such as myocardial infarction, certain infectious diseases and endocrine disorders, can initiate a primary pathophysiological process that can lead to reduced ventricular function and to heart failure. Initially, ventricular impairment is compensated for by the activation of the sympathetic nervous system and the renin-angiotensin-aldosterone system, but chronic activation of these pathways leads to worsening cardiac function. The symptoms of heart failure can be associated with other conditions and include dyspnoea, fatigue, limitations in exercise tolerance and fluid accumulation, which can make diagnosis difficult. Management strategies include the use of pharmacological therapies and implantable devices to regulate cardiac function. Despite these available treatments, heart failure remains incurable, and patients have a poor prognosis and high mortality rate. Consequently, the development of new therapies is imperative and requires further research.

Regulation of Pulmonary Vascular Smooth Muscle Contractility in Pulmonary Arterial Hypertension: Implications for Therapy

There are two primary components that produce pulmonary arterial hypertension (PAH); aberrant structural changes (smooth muscle cell proliferation, smooth muscle cell hypertrophy, and the deposition of matrix proteins within the media of pulmonary arterial vessels), and excess vasoconstriction. However, in PAH, the target and aim of all current therapeutic agents is to reduce the contractility of the pulmonary vasculature; prostaglandins, phosphodiesterase inhibitors, guanylate cyclase stimulators, endothelin antagonists, NO inhalation and Rho kinase inhibitors all influence signaling pathways in the pulmonary vascular smooth muscle to decrease vasoconstriction, and hence, pulmonary vascular resistance (PVR). This review will therefore primarily focus on discussing the signaling pathways regulating contractility in pulmonary vascular smooth muscle, the mechanism for current treatments, as well as highlighting potential targets for the development of novel therapies.

Prevention of Atrial Fibrillation by Using Sarcoplasmic Reticulum Calcium ATPase Pump Overexpression in a Rabbit Model of Rapid Atrial Pacing

BACKGROUND Recent research suggests that abnormal Ca2+ handling plays a role in the occurrence and maintenance of atrial fibrillation (AF). Therefore, Ca2+ release and ingestion depend on properties of the ryanodine receptor (RyR) and sarcoplasmic reticulum Ca2+ATPase2a (SERCA2a). This study aimed to detect whether SERCA2a gene overexpression has a preventive effect on atrial fibrillation caused by rapid pacing right atrium. MATERIAL AND METHODS Forty-eight New Zealand white rabbits were randomly divided into a control group, AF group, AAV9/GFP group, and AAV9/SERCA2a group. The right atrium was rapidly paced at 600 beats/min for 30 days after an intraperitoneal injection of an adeno-associated virus expressing the SERCA2a gene and GFP. The AF induction rate and the effective refraction period (ERP) were measured after 0, 4, 8, 12, and 24 h of pacing. Western blot analysis was used to test for the expression of SERCA2a. Changes in atrial tissue structure were observed by H&E staining and electron microscopy. RESULTS The AF induction rate was higher in the AF groups than in the AAV9/SERCA2a group at different time points of pacing. After 12 h of pacing, ERP was significantly prolonged in the AAV9/SERCA2a group compared to the AF and AAV9/GFP groups (p<0.05). SERCA2a protein expression was significantly lower in the AF and AAV9/GFP groups compared to the control group (p<0.05), while expression was significantly higher in the AAV9/SERCA2a group than in the AF and AAV9/GFP groups (p<0.05). The myocardial structure of the AAV9/SERCA2a group was significantly improved compared with the AF group, indicating that SERCA2a overexpression relieved the structural remodeling of atrial fibrillation. CONCLUSIONS SERCA2a overexpression is capable of suppressing ERP shortening and AF induced by rapid pacing atrium. SERCA2a gene therapy is expected to be a new anti-atrial fibrillation strategy.

Early Right Ventricular Apical Pacing-Induced Gene Expression Alterations Are Associated with Deterioration of Left Ventricular Systolic Function

The chronic high-dose right ventricular apical (RVA) pacing may have deleterious effects on left ventricular (LV) systolic function. We hypothesized that the expression changes of genes regulating cardiomyocyte energy metabolism and contractility were associated with deterioration of LV function in patients who underwent chronic RVA pacing. Sixty patients with complete atrioventricular block and preserved ejection fraction (EF) who underwent pacemaker implantation were randomly assigned to either RVA pacing (n = 30) group or right ventricular outflow tract (RVOT) pacing (n = 30) group. The mRNA levels of OPA1 and SERCA2a were significantly lower in the RVA pacing group at 1 month's follow-up (both p < 0.001). Early changes in the expression of selected genes OPA1 and SERCA2a were associated with deterioration in global longitudinal strain (GLS) that became apparent months later (p = 0.002 and p = 0.026, resp.) The altered expressions of genes that regulate cardiomyocyte energy metabolism and contractility measured in the peripheral blood at one month following pacemaker implantation were associated with subsequent deterioration in LV dyssynchrony and function in patients with preserved LVEF, who underwent RVA pacing.

The Function and Therapeutic Potential of Long Non-coding RNAs in Cardiovascular Development and Disease

The popularization of genome-wide analyses and RNA sequencing led to the discovery that a large part of the human genome, while effectively transcribed, does not encode proteins. Long non-coding RNAs have emerged as critical regulators of gene expression in both normal and disease states. Studies of long non-coding RNAs expressed in the heart, in combination with gene association studies, revealed that these molecules are regulated during cardiovascular development and disease. Some long non-coding RNAs have been functionally implicated in cardiac pathophysiology and constitute potential therapeutic targets. Here, we review the current knowledge of the function of long non-coding RNAs in the cardiovascular system, with an emphasis on cardiovascular development and biology, focusing on hypertension, coronary artery disease, myocardial infarction, ischemia, and heart failure. We discuss potential therapeutic implications and the challenges of long non-coding RNA research, with directions for future research and translational focus.

Genome editing abrogates angiogenesis in vivo

Angiogenesis, in which vascular endothelial growth factor receptor (VEGFR) 2 plays an essential role, is associated with a variety of human diseases including proliferative diabetic retinopathy and wet age-related macular degeneration. Here we report that a system of adeno-associated virus (AAV)-mediated clustered regularly interspaced short palindromic repeats (CRISPR)-associated endonuclease (Cas)9 from Streptococcus pyogenes (SpCas9) is used to deplete VEGFR2 in vascular endothelial cells (ECs), whereby the expression of SpCas9 is driven by an endothelial-specific promoter of intercellular adhesion molecule 2. We further show that recombinant AAV serotype 1 (rAAV1) transduces ECs of pathologic vessels, and that editing of genomic VEGFR2 locus using rAAV1-mediated CRISPR/Cas9 abrogates angiogenesis in the mouse models of oxygen-induced retinopathy and laser-induced choroid neovascularization. This work establishes a strong foundation for genome editing as a strategy to treat angiogenesis-associated diseases.

Abnormal angiogenesis causes many ocular diseases. Here the authors employ CRISPR/Cas9 gene editing technology to silence VEGFR2, a major regulator of angiogenesis, in retinal endothelium and abrogate angiogenesis in the mouse models of oxygen-induced retinopathy and laser-induced choroid neovascularization.

Improving Atrial Fibrillation Therapy: Is There a Gene for That?

Atrial fibrillation (AF) is an all-too-common and often challenging reality of clinical care. AF leads to significant morbidity and mortality; however, currently available treatments for AF have modest efficacy and high recurrence rates. In recent years, genetic therapy approaches have been explored in preclinical models of AF, and offer potential as a treatment modality with targeted delivery, tissue specificity, and therapy tailored to address mechanisms underlying the arrhythmia. However, many challenges remain before gene therapy can advance to a clinically relevant AF treatment. In this review, we summarize the available published data on gene therapy and discuss the challenges, opportunities, and limitations of this approach.

SERCA control of cell death and survival

Intracellular calcium (Ca²⁺⁾ is a critical coordinator of various aspects of cellular physiology. It is increasingly apparent that changes in cellular Ca²⁺ dynamics contribute to the regulation of normal and pathological signal transduction that controls cell growth and survival. Aberrant perturbations in Ca²⁺ homeostasis have been implicated in a range of pathological conditions, such as cardiovascular diseases, diabetes, tumorigenesis and steatosis hepatitis. Intracellular Ca²⁺ concentrations are therefore tightly regulated by a number of Ca²⁺ handling enzymes, proteins, channels and transporters located in the plasma membrane and in Ca²⁺ storage organelles, which work in concert to fine tune a temporally and spatially precise Ca²⁺ signal. Chief amongst them is the sarco/endoplasmic reticulum (SR/ER) Ca²⁺ ATPase pump (SERCA) which actively re-accumulates released Ca²⁺ back into the SR/ER, therefore maintaining Ca²⁺ homeostasis. There are at least 14 different SERCA isoforms encoded by three ATP2A1-3 genes whose expressions are species- and tissue-specific. Altered SERCA expression and activity results in cellular malignancy and induction of ER stress and ER stress-associated apoptosis. The role of SERCA misregulation in the control of apoptosis in various cell types and disease setting with prospective therapeutic implications is the focus of this review. Ca²⁺ is a double edge sword for both life as well as death, and current experimental evidence supports a model in which Ca²⁺ homeostasis and SERCA activity represent a nodal point that controls cell survival. Pharmacological or genetic targeting of this axis constitutes an incredible therapeutic potential to treat different diseases sharing similar biological disorders.

The function of DNA binding protein nucleophosmin in AAV replication

Adeno-associated viruses (AAV) contain minimal viral proteins necessary for their replication. During virus assembly, AAV acquire, inherently and submissively, various cellular proteins. Our previous studies identified the association of AAV vectors with the DNA binding protein nucleophosmin (NPM1). Nucleophosmin has been reported to enhance AAV infection by mobilizing AAV capsids into and out of the nucleolus, indicating the importance of NPM1 in the AAV life cycle; however the role of NPM1 in AAV production remains unknown. In this study, we systematically investigated NPM1 function on AAV production using NPM1 knockdown cells and revealing for the first time the presence of G-quadruplex DNA sequences (GQRS) in the AAV genome, the synergistic NPM1-GQRS function in AAV production and the significant enhancement of NPM1 gene knockdown on AAV vector production. Understanding the role of cellular proteins in the AAV life cycle will greatly facilitate high titre production of AAV vectors for clinical use.

SERCA2a: A potential non-invasive biomarker of cardiac allograft rejection

BACKGROUND

The detection of heart transplant rejection by non-invasive methods remains a major challenge. Despite the well-known importance of the study of sarcoplasmic reticulum Ca²⁺-ATPase (SERCA2a) in the heart, its role as a rejection marker has never been analyzed. Our objective in this study was to determine whether circulating SERCA2a could be a good marker of cardiac rejection.

METHODS

We collected 127 consecutive endomyocardial biopsies (EMBs) and serum samples from adult heart transplant recipients (49 without allograft rejection and 78 with the diagnosis of biopsy allograft rejection, including 48 Grade 1R, 21 Grade 2R and 9 Grade 3R). Serum concentrations of SERCA2a were determined using a specific sandwich enzyme-linked immunosorbent assay. We also analyzed SERCA2a expression changes on EMBs using immunofluorescence.

RESULTS

SERCA2a cardiac tissue and serum levels were decreased in patients with cardiac rejection (p < 0.0001). A receiver-operating characteristic analysis showed that SERCA2a strongly discriminated between patients with and without allograft rejection: normal grafts vs all rejecting grafts (AUC = 0.804); normal grafts vs Grade 1R (AUC = 0.751); normal grafts vs Grade 2R (AUC = 0.875); normal grafts vs Grade 3R (AUC = 0.922); normal grafts vs Grade 2R and 3R (AUC = 0.889), with p < 0.0001 for all comparisons.

CONCLUSIONS

We demonstrated that changes in SERCA2a cardiac tissue and serum levels occur in cardiac allograft rejection. Our findings suggest that SERCA2a concentration assessment may be a relatively simple, non-invasive test for heart transplant rejection, showing a strong capability for detection that improves progressively as rejection grades increase.

Gene Therapy With Angiotensin-(1-9) Preserves Left Ventricular Systolic Function After Myocardial Infarction

Background

Angiotensin-(1-9) [Ang-(1-9)] is a novel peptide of the counter-regulatory axis of the renin-angiotensin-aldosterone system previously demonstrated to have therapeutic potential in hypertensive cardiomyopathy when administered via osmotic mini-pump. Here, we investigate whether gene transfer of Ang-(1-9) is cardioprotective in a murine model of myocardial infarction (MI).

Objectives

The authors evaluated effects of Ang-(1-9) gene therapy on myocardial structural and functional remodeling post-infarction.

Methods

C57BL/6 mice underwent permanent left anterior descending coronary artery ligation and cardiac function was assessed using echocardiography for 8 weeks followed by a terminal measurement of left ventricular pressure volume loops. Ang-(1-9) was delivered by adeno-associated viral vector via single tail vein injection immediately following induction of MI. Direct effects of Ang-(1-9) on cardiomyocyte excitation/contraction coupling and cardiac contraction were evaluated in isolated mouse and human cardiomyocytes and in an ex vivo Langendorff-perfused whole-heart model.

Results

Gene delivery of Ang-(1-9) reduced sudden cardiac death post-MI. Pressure volume measurements revealed complete restoration of end-systolic pressure, ejection fraction, end-systolic volume, and the end-diastolic pressure volume relationship by Ang-(1-9) treatment. Stroke volume and cardiac output were significantly increased versus sham. Histological analysis revealed only mild effects on cardiac hypertrophy and fibrosis, but a significant increase in scar thickness. Direct assessment of Ang-(1-9) on isolated cardiomyocytes demonstrated a positive inotropic effect via increasing calcium transient amplitude and contractility. Ang-(1-9) increased contraction in the Langendorff model through a protein kinase A–dependent mechanism.

Conclusions

Our novel findings showed that Ang-(1-9) gene therapy preserved left ventricular systolic function post-MI, restoring cardiac function. Furthermore, Ang-(1-9) directly affected cardiomyocyte calcium handling through a protein kinase A–dependent mechanism. These data emphasized Ang-(1-9) gene therapy as a potential new strategy in the context of MI.

Status of Therapeutic Gene Transfer to Treat Cardiovascular Disease in Dogs and Cats

Gene therapy is a procedure resulting in the transfer of a gene into an individual's cells to treat a disease. One goal of gene transfer is to express a functional gene when the endogenous gene is inactive. However, because heart failure is a complex disease characterized by multiple abnormalities at the cellular level, an alternate gene delivery approach is to alter myocardial protein levels to improve function. This article discusses background information on gene delivery, including packaging, administration, and a brief discussion of some of the candidate transgenes likely to alter the progression of naturally occurring heart disease in dogs and cats.

Cardiovascular Pharmacology: An Update and Anesthesia Considerations

Cardiovascular disease remains a leading cause of morbidity and mortality worldwide. The development of therapeutic agents for the treatment of cardiovascular diseases has always been a priority because of the huge potential market for these drugs. These medications should be part of the anesthesiologist's armamentarium because the typical surgical patient is older and has more comorbidities than in the past. This article reviews commonly used cardiovascular medications that are important in managing patients with unstable hemodynamics.

Cardioprotective effects of Qishen Granule () on sarcoplasmic reticulum Ca2+ handling in heart failure rats

OBJECTIVE

To assess the effects of Qishen Granule (, QSG) on sarcoplasmic reticulum (SR) Ca²⁺ handling in heart failure (HF) model of rats and to explore the underlying molecular mechanisms.

METHODS

HF rat models were induced by left anterior descending coronary artery ligation surgery and high-fat diet feeding. Rats were randomly divided into sham (n=10), model (n=10), QSG (n=12, 2.2 g/kg daily) and metoprolol groups (n=12, 10.5 mg/kg daily). The therapeutic effects of QSG were evaluated by echocardiography and blood lipid testing. Intracellular Ca²⁺ concentration and sarco-endoplasmic reticulum ATPase 2a (SERCA2a) activity were detected by specifific assay kits. Expressions of the critical regulators in SR Ca²⁺ handling were evaluated by Western blot and real-time quantitative polymerase chain reaction.

RESULTS

HF model of rats developed ventricular remodeling accompanied with calcium overload and defective Ca²⁺ release-uptake cycling in cardiomyocytes. Treatment with QSG improved contractive function, attenuated ventricular remodeling and reduced the basal intracellular Ca²⁺ level. QSG prevented defective Ca²⁺ leak by attenuating hyperphosphorylation of ryanodine receptor 2, inhibiting expression of protein kinase A and up-regulating transcriptional expression of protein phosphatase 1. QSG also restored Ca²⁺ uptake by up-regulating expression and activity of SERCA2a and promoting phosphorylation of phospholamban.

CONCLUSION

QSG restored SR Ca²⁺ cycling in HF rats and served as an ideal alternative drug for treating HF.

Optogenetics gets to the heart: A guiding light beyond defibrillation

Optogenetics provides a tool for controlling the electrical activity of excitable cells by means of the interaction of light with light-gated ion channels. Despite the fact that optogenetics has been intensively utilized in the neurosciences, it has been more rarely employed as an instrument for studying cardiac pathophysiology. However, the advantages of optical approaches to perturb cardiac electrical activity are numerous, especially when the spatio-temporal qualities of light are utterly exploited. Here, we review the main breakthroughs employing optogenetics to perturb cardiac pathophysiology and attempt a comparison of methods and procedures that have employed optogenetics in the heart. We particularly focus on light-based defibrillation strategies that represent one of the latest achievements in this field. We highlight the important role of advanced optical methods for detecting and stimulating electrical activity for optimizing defibrillation strategies and, more generally, for dissecting novel insights in cardiac physiology. Finally, we discuss the main future perspectives that we envision for optogenetics in the heart, both in terms of translational applications and for addressing fundamental questions of cardiac function.

Cardiac gene therapy with adeno-associated virus-based vectors

PURPOSE OF REVIEW

Cardiac gene therapy with adeno-associated virus (AAV)-based vectors is emerging as an entirely new platform to treat, or even cure, so far intractable cardiac disorders. This review describes our current knowledge of cardiac AAV gene therapy with a particular focus on the biggest obstacle for the successful translation of cardiac AAV gene therapy into the clinic, namely the efficient delivery of the therapeutic gene to the myocardium.

RECENT FINDINGS

We summarize the significant recent progress that has been made in treating heart failure in preclinically relevant animal models with AAV gene therapy and the recent results of clinical trials with cardiac AAV gene therapy for the treatment of heart failure. We also discuss the benefits and shortcomings of the currently available delivery methods of AAV to the heart. Finally, we describe the current state of identifying novel AAV variants that have enhanced tropism for human cardiomyocytes and that show increased resistance to preexisting neutralizing antibodies.

SUMMARY

Here, we describe the successes and challenges in cardiac AAV gene therapy, a treatment modality that has the potential to transform current treatment approaches for cardiac diseases.

Cardiomyocyte Ca2+ homeostasis as a therapeutic target in heart failure with reduced and preserved ejection fraction

Heart failure is a highly prevalent syndrome of multiple etiologies and associated comorbidities, and aberrant intracellular Ca²⁺ homeostasis is a hallmark finding in heart failure patients. The cyclical changes in Ca²⁺ concentration within cardiomyocytes control cycles of cardiac contraction and relaxation, and dysregulation of Ca²⁺ handling processes leads to systolic dysfunction, diastolic dysfunction, and adverse remodeling. For this reason, greater understanding of Ca²⁺ handling mechanisms in heart failure is critical for selection of appropriate treatment strategies. In this review, we summarize the mechanisms of altered Ca²⁺ handling in two subsets of heart failure, heart failure with reduced ejection fraction and heart failure with preserved ejection fraction, and outline current and experimental treatments that target cardiomyocyte Ca²⁺ handling processes.

Sustained viral gene delivery from a micro-fibrous, elastomeric cardiac patch to the ischemic rat heart

Biodegradable and elastomeric patches have been applied to the surface of infarcted hearts as temporary mechanical supports to effectively alter adverse left ventricular remodeling processes. In this report, recombinant adeno-associated virus (AAV), known for its persistent transgene expression and low pathogenicity, was incorporated into elastomeric polyester urethane urea (PEUU) and polyester ether urethane urea (PEEUU) and processed by electrospinning into two formats (solid fibers and core-sheath fibers) designed to influence the controlled release behavior. The extended release of AAV encoding green fluorescent protein (GFP) was assessed in vitro. Sustained and localized viral particle delivery was achieved over 2 months in vitro. The biodegradable cardiac patches with or without AAV-GFP were implanted over rat left ventricular lesions three days following myocardial infarction to evaluate the transduction effect of released viral vectors. AAV particles were directly injected into the infarcted hearts as a control. Cardiac function and remodeling were significantly improved for 12 weeks after patch implantation compared to AAV injection. More GFP genes was expressed in the AAV patch group than AAV injection group, with both α-SMA positive cells and cardiac troponin T positive cells transduced in the patch group. Overall, the extended release behavior, prolonged transgene expression, and elastomeric mechanical properties make the AAV-loaded scaffold an attractive option for cardiac tissue engineering where both gene delivery and appropriate mechanical support are desired.

Emerging molecular therapies targeting myocardial infarction-related arrhythmias

Cardiac disease is the leading cause of death in the developed world. Ventricular arrhythmias associated with myocardial ischaemia and/or infarction are a major contributor to cardiovascular mortality, and require improved prevention and treatment. Drugs, devices, and radiofrequency catheter ablation have made important inroads, but have significant limitations ranging from incomplete success to undesired toxicities and major side effects. These limitations derive from the nature of the intervention. Drugs are frequently ineffective, target the entire heart, and often do not deal with the specific arrhythmia trigger or substrate. Devices can terminate rapid rhythms but at best indirectly affect the underlying disease, while ablation, even when appropriately targeted, induces additional tissue damage. In contrast, exploration of gene and cell therapies are expected to provide a targeted, non-destructive, and potentially regenerative approach to ischaemia- and infarction-related arrhythmias. Although these approaches are in the early stages of development, they carry substantial potential to advance arrhythmia prevention and treatment.

Concise Review: Mending a Broken Heart: The Evolution of Biological Therapeutics

Heart failure (HF), a common sequela of cardiovascular diseases, remains a staggering clinical problem, associated with high rates of morbidity and mortality worldwide. Advances in pharmacological, interventional, and operative management have improved patient care, but these interventions are insufficient to halt the progression of HF, particularly the end-stage irreversible loss of functional cardiomyocytes. Innovative therapies that could prevent HF progression and improve the function of the failing heart are urgently needed. Following successful preclinical studies, two main strategies have emerged as potential solutions: cardiac gene therapy and cardiac regeneration through stem and precursor cell transplantation. Many potential gene- and cell-based therapies have entered into clinical studies, intending to ameliorate cardiac dysfunction in patients with advanced HF. In this review, we focus on the recent advances in cell- and gene-based therapies in the context of cardiovascular disease, emphasizing the most advanced therapies. The principles and mechanisms of action of gene and cell therapies for HF are discussed along with the limitations of current approaches. Finally, we highlight the emerging technologies that hold promise to revolutionize the biological therapies for cardiovascular diseases. Stem Cells 2017;35:1131-1140.

Randomized Clinical Trials of Gene Transfer for Heart Failure with Reduced Ejection Fraction

Despite improvements in drug and device therapy for heart failure, hospitalization rates and mortality have changed little in the past decade. Randomized clinical trials using gene transfer to improve function of the failing heart are the focus of this review. Four randomized clinical trials of gene transfer in heart failure with reduced ejection fraction (HFrEF) have been published. Each enrolled patients with stable symptomatic HFrEF and used either intracoronary delivery of a virus vector or endocardial injection of a plasmid. The initial CUPID trial randomized 14 subjects to placebo and 25 subjects to escalating doses of adeno-associated virus type 1 encoding sarcoplasmic reticulum calcium ATPase (AAV1.SERCA2a). AAV1.SERCA2a was well tolerated, and the high-dose group met a 6 month composite endpoint. In the subsequent CUPID-2 study, 243 subjects received either placebo or the high dose of AAV1.SERCA2a. AAV1.SERCA2a administration, while safe, failed to meet the primary or any secondary endpoints. STOP-HF used plasmid endocardial injection of stromal cell-derived factor-1 to promote stem-cell recruitment. In a 93-subject trial of patients with ischemic etiology heart failure, the primary endpoint (symptoms and 6 min walk distance) failed, but subgroup analyses showed improvements in subjects with the lowest ejection fractions. A fourth trial randomized 14 subjects to placebo and 42 subjects to escalating doses of adenovirus-5 encoding adenylyl cyclase 6 (Ad5.hAC6). There were no safety concerns, and patients in the two highest dose groups (combined) showed improvements in left ventricular function (left ventricular ejection fraction and -dP/dt). The safety data from four randomized clinical trials of gene transfer in patients with symptomatic HFrEF suggest that this approach can be conducted with acceptable risk, despite invasive delivery techniques in a high-risk population. Additional trials are necessary before the approach can be endorsed for clinical practice.

Gene Editing With CRISPR/Cas9 RNA-Directed Nuclease

Genetic engineering of model organisms and cultured cells has for decades provided important insights into the mechanisms underlying cardiovascular development and disease. In the past few years the development of several nuclease systems has broadened the range of model/cell systems that can be engineered. Of these, the CRISPR (clustered regularly interspersed short palindromic repeats)/Cas9 (CRISPR-associated protein 9) system has become the favorite for its ease of application. Here we will review this RNA-guided nuclease system for gene editing with respect to its usefulness for cardiovascular studies and with an eye toward potential therapy. Studies on its off-target activity, along with approaches to minimize this activity will be given. The advantages of gene editing versus gene targeting in embryonic stem cells, including the breadth of species and cell types to which it is applicable, will be discussed. We will also cover its use in iPSC for research and possible therapeutic purposes; and we will review its use in muscular dystrophy studies where considerable progress has been made toward dystrophin correction in mice. The CRISPR/Ca9s system is also being used for high-throughput screening of genes, gene regulatory regions, and long noncoding RNAs. In addition, the CRISPR system is being used for nongene-editing purposes such as activation and inhibition of gene expression, as well as for fluorescence tagging of chromosomal regions and individual mRNAs to track their cellular location. Finally, an approach to circumvent the inability of post-mitotic cells to support homologous recombination-based gene editing will be presented. In conclusion, applications of the CRISPR/Cas system are expanding at a breath-taking pace and are revolutionizing approaches to gain a better understanding of human diseases.

Biphasic Force-Frequency Relation Predicts Primary Cardiac Events in Patients With Hypertrophic Cardiomyopathy

BACKGROUND

The force-frequency relation (FFR) is a hemodynamic index of the chronotropic relationship between left ventricular (LV) systolic function (percent change in dP/dtmax) and elevation of heart rate. FFR is a marker of myocardial contractile reserve and follows an upward slope in healthy myocardium [monophasic FFR (MoF)], a pattern that becomes biphasic (BiF) under pathological conditions. However, it remains uncertain whether the FFR determines a patient's prognosis. We investigated the promising role of the FFR as a predictor of cardiac events in the setting of hypertrophic cardiomyopathy (HCM).

METHODS AND RESULTS

A total of 113 consecutive patients with HCM (New York Heart Association (NYHA) class I-II) were retrospectively evaluated; 27 (23.9%) had a BiF pattern and they experienced a higher incidence of cardiac events compared with those showing an MoF pattern (median follow-up, 4.7 years; P<0.001). Furthermore, Cox proportional hazard regression analysis revealed that the LV end-diastolic volume index (hazard ratio: 1.051, P=0.014) and BiF pattern (hazard ratio: 15.260, P=0.001) were independent predictors of primary cardiac events. Interestingly, abnormal reductions in myocardial regulatory molecules related to contractility (SERCA2α) were observed exclusively in the patients exhibiting a BiF pattern.

CONCLUSIONS

The FFR reflects latent myocardial abnormalities and predicts cardiac events in the setting of HCM, even during the asymptomatic stages of the disease.

Overexpression of Sarcoendoplasmic Reticulum Calcium ATPase 2a Promotes Cardiac Sympathetic Neurotransmission via Abnormal Endoplasmic Reticulum and Mitochondria Ca2+ Regulation

Supplemental Digital Content is available in the text.

Reduced cardiomyocyte excitation–contraction coupling and downregulation of the SERCA2a (sarcoendoplasmic reticulum calcium ATPase 2a) is associated with heart failure. This has led to viral transgene upregulation of SERCA2a in cardiomyocytes as a treatment. We hypothesized that SERCA2a gene therapy expressed under a similar promiscuous cytomegalovirus promoter could also affect the cardiac sympathetic neural axis and promote sympathoexcitation. Stellate neurons were isolated from 90 to 120 g male, Sprague–Dawley, Wistar Kyoto, and spontaneously hypertensive rats. Neurons were infected with Ad-mCherry or Ad-mCherry-hATP2Aa (SERCA2a). Intracellular Ca²⁺ changes were measured using fura-2AM in response to KCl, caffeine, thapsigargin, and carbonylcyanide-p-trifluoromethoxyphenylhydrazine to mobilize intracellular Ca²⁺ stores. The effect of SERCA2a on neurotransmitter release was measured using [³H]-norepinephrine overflow from 340 to 360 g Sprague–Dawley rat atria in response to right stellate ganglia stimulation. Upregulation of SERCA2a resulted in greater neurotransmitter release in response to stellate stimulation compared with control (empty: 98.7±20.5 cpm, n=7; SERCA: 186.5±28.41 cpm, n=8; P<0.05). In isolated Sprague–Dawley rat stellate neurons, SERCA2a overexpression facilitated greater depolarization-induced Ca²⁺ transients (empty: 0.64±0.03 au, n=57; SERCA: 0.75±0.03 au, n=68; P<0.05), along with increased endoplasmic reticulum and mitochondria Ca²⁺ load. Similar results were observed in Wistar Kyoto and age-matched spontaneously hypertensive rats, despite no further increase in endoplasmic reticulum load being observed in the spontaneously hypertensive rat (spontaneously hypertensive rats: empty, 0.16±0.04 au, n=18; SERCA: 0.17±0.02 au, n=25). In conclusion, SERCA2a upregulation in cardiac sympathetic neurons resulted in increased neurotransmission and increased Ca²⁺ loading into intracellular stores. Whether the increased Ca²⁺ transient and neurotransmission after SERCA2A overexpression contributes to enhanced sympathoexcitation in heart failure patients remains to be determined.

Luteolin improves cardiac dysfunction in heart failure rats by regulating sarcoplasmic reticulum Ca2+-ATPase 2a

We previously found that luteolin (Lut) appeared to improve the contractility of cardiomyocytes during ischemia/reperfusion in rats. The enhancement was associated with the alteration in sarcoplasmic reticulum Ca²⁺-ATPase 2a (SERCA2a). This finding prompted us to consider if the mechanism worked in heart failure (HF). We studied the regulation of SERCA2a by Lut in failing cardiomyocytes and intact heart of rats. Improvement of contractility and the mechanisms centered on SERCA2a were studied in isolated cardiomyocytes and intact heart. We found that Lut significantly improved contractility and Ca²⁺ transients, ameliorated expression, activity and stability of SERCA2a and upregulated expression of small ubiquitin-related modifier (SUMO) 1, which is a newfound SERCA2a regulator. Lut also increased phosphorylation of protein kinase B (Akt), phospholaban (PLB) and sumoylation of SERCA2a, specificity protein 1 (Sp1). Transcriptions of SUMO1 and SERCA2a were concurrently increased. Inhibition of posphatidylinositol 3 kinase/Akt (PI3K/Akt) pathway and SERCA2a activity both markedly abolished Lut-induced benefits in vitro and in vivo. Lut upregulated the expression ratio of Bcl-2/Bax, caspase-3/cleaved-Caspase3. Meanwhile, Lut ameliorated the myocardium fibrosis of HF. These discoveries provide an important potential therapeutic strategy that Lut targeted SERCA2a SUMOylation related to PI3K/Akt-mediated regulations on rescuing the dysfunction of HF.

Cardiac Gene Delivery Using Recirculating Devices

Cardiac gene delivery has become an important issue following the emergence of gene therapy for the possible treatment of heart failure. Despite many advances in the management of heart failure (HF), treatment options for many patients with advanced HF remain limited. At a cellular and molecular level, many of the fundamental alterations that contribute to the pathogenesis of HF are becoming better understood and this has resulted in the discovery of new therapeutic targets in animal models of HF, in particular in the area of gene therapy.Numerous small animal and preclinical studies have examined the efficacy of delivering genes targeting various signaling pathways that are affected as the heart fails. However, the translation of this work into the clinic has been difficult due to the requirement for large scale targeted delivery of the gene. This methods chapter describes a percutaneous method of recirculation that we have employed to successfully deliver potential therapeutic agents, including genes, to the heart.

Current Methods in Cardiac Gene Therapy: Overview

During the last decade, there has been a significant progress toward clinical translation in the field of cardiac gene therapy based on extensive preclinical data. However, despite encouraging positive results in early phase clinical trials, more recent larger trials reported only neutral results. Nevertheless, the field has gained important knowledge from these trials and is leading to the development of more cardiotropic vectors and improved delivery systems. It has become more evident that humans are more resistant to therapeutic transgene expression compared to experimental animals and thus refinement in gene delivery tools and methods are essential for future success. We provide an overview of the current status of cardiac gene therapy focusing on gene delivery tools and methods. Newer technologies, devices, and approaches will undoubtedly lead to more promising clinical results in the near future.