Single intracoronary injection of encapsulated antagomir-92a promotes angiogenesis and prevents adverse infarct remodeling

Post-Genomic Methodologies and Preclinical Animal Models: Chances for the Translation of Cardioprotection to the Clinic

Although many cardioprotective strategies have demonstrated benefits in animal models of myocardial infarction, they have failed to demonstrate cardioprotection in the clinical setting highlighting that new therapeutic target and treatment strategies aimed at reducing infarct size are urgently needed. Completion of the Human Genome Project in 2001 fostered the post-genomic research era with the consequent development of high-throughput “omics” platforms including transcriptomics, proteomics, and metabolomics. Implementation of these holistic approaches within the field of cardioprotection has enlarged our understanding of ischemia/reperfusion injury with each approach capturing a different angle of the global picture of the disease. It has also contributed to identify potential prognostic/diagnostic biomarkers and discover novel molecular therapeutic targets. In this latter regard, “omic” data analysis in the setting of ischemic conditioning has allowed depicting potential therapeutic candidates, including non-coding RNAs and molecular chaperones, amenable to pharmacological development. Such discoveries must be tested and validated in a relevant and reliable myocardial infarction animal model before moving towards the clinical setting. Moreover, efforts should also focus on integrating all “omic” datasets rather than working exclusively on a single “omic” approach. In the following manuscript, we will discuss the power of implementing “omic” approaches in preclinical animal models to identify novel molecular targets for cardioprotection of interest for drug development.

MicroRNA-regulated pathways of flow-stimulated angiogenesis and vascular remodeling in vivo

BACKGROUND

Vascular shear stress promotes endothelial cell sprouting in vitro. The impact of hemodynamic forces on microRNA (miRNA) and gene expression within growing vascular networks in vivo, however, remain poorly investigated. Arteriovenous (AV) shunts are an established model for induction of neoangiogenesis in vivo and can serve as a tool for analysis of hemodynamic effects on miRNA and gene expression profiles over time.

METHODS

AV shunts were microsurgically created in rats and explanted on postoperative days 5, 10 and 15. Neoangiogenesis was confirmed by histologic analysis and micro-computed tomography. MiRNA and gene expression profiles were determined in tissue specimens from AV shunts by microarray analysis and quantitative real-time polymerase chain reaction and compared with sham-operated veins by bioinformatics analysis. Changes in protein expression within AV shunt endothelial cells were determined by immunohistochemistry.

RESULTS

Samples from AV shunts exhibited a strong overexpression of proangiogenic cytokines, oxygenation-associated genes (HIF1A, HMOX1), and angiopoetic growth factors. Significant inverse correlations of the expressions of miR-223-3p, miR-130b-3p, miR-19b-3p, miR-449a-5p, and miR-511-3p which were up-regulated in AV shunts, and miR-27b-3p, miR-10b-5p, let-7b-5p, and let-7c-5p, which were down-regulated in AV shunts, with their predicted interacting targets C-X-C chemokine receptor 2 (CXCR2), interleukin-1 alpha (IL1A), ephrin receptor kinase 2 (EPHA2), synaptojanin-2 binding protein (SYNJ2BP), forkhead box C1 (FOXC1) were present. CXCL2 and IL1A overexpression in AV shunt endothelium was confirmed at the protein level by immunohistochemistry.

CONCLUSIONS

Our data indicate that flow-stimulated angiogenesis is determined by an upregulation of cytokines, oxygenation associated genes and miRNA-dependent regulation of FOXC1, EPHA2 and SYNJ2BP.

Targeting Non-coding RNA in Vascular Biology and Disease

Only recently have we begun to appreciate the importance and complexity of the non-coding genome, owing in some part to truly significant advances in genomic technology such as RNA sequencing and genome-wide profiling studies. Previously thought to be non-functional transcriptional “noise,” non-coding RNAs (ncRNAs) are now known to play important roles in many diverse biological pathways, not least in vascular disease. While microRNAs (miRNA) are known to regulate protein-coding gene expression principally through mRNA degradation, long non-coding RNAs (lncRNAs) can activate and repress genes by a variety of mechanisms at both transcriptional and translational levels. These versatile molecules, with complex secondary structures, may interact with chromatin, proteins, and other RNA to form complexes with an array of functional consequences. A body of emerging evidence indicates that both classes of ncRNAs regulate multiple physiological and pathological processes in vascular physiology and disease. While dozens of miRNAs are now implicated and described in relative mechanistic depth, relatively fewer lncRNAs are well described. However, notable examples include ANRIL, SMILR, and SENCR in vascular smooth muscle cells; MALAT1 and GATA-6S in endothelial cells; and mitochondrial lncRNA LIPCAR as a powerful biomarker. Due to such ubiquitous involvement in pathology and well-known biogenesis and functional genetics, novel miRNA-based therapies and delivery methods are now in development, including some early stage clinical trials. Although lncRNAs may hold similar potential, much more needs to be understood about their relatively complex molecular behaviours before realistic translation into novel therapies. Here, we review the current understanding of the mechanism and function of ncRNA, focusing on miRNAs and lncRNAs in vascular disease and atherosclerosis. We discuss existing therapies and current delivery methods, emphasising the importance of miRNAs and lncRNAs as effectors and biomarkers in vascular pathology.

miRNAS in cardiovascular diseases: potential biomarkers, therapeutic targets and challenges

Cardiovascular diseases (CVD) are the leading cause of morbidity and mortality in the world. Although considerable progress has been made in the diagnosis, treatment and prognosis of CVD, there is still a critical need for novel diagnostic biomarkers and new therapeutic interventions to decrease the incidence of this disease. Recently, there is increasing evidence that circulating miRNAs (miRNAs), i.e. endogenous, stable, single-stranded, short, non-coding RNAs, can be used as diagnostic biomarkers for CVD. Furthermore, miRNAs represent potential novel therapeutic targets for several cardiovascular disorders. In this review we provides an overview of the effects of several CVD; including heart failure, acute myocardial infarction, arrhythmias and pulmonary hypertension; on levels of circulating miRNAs. In addition, the use of miRNA as therapeutic targets is also discussed, as well as challenges and recommendations in their use in the diagnosis of CVD.

Role of epinephrine and extracorporeal membrane oxygenation in the management of ischemic refractory ventricular fibrillation: a randomized trial in pigs

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The Minnesota Resuscitation Consortium has established a protocol for rapid transport of patients with refractory out-of-hospital VF cardiac arrest to the cardiac catheterization laboratory for rapid evaluation and stabilization often requiring ECMO. This protocol provides new challenges to treatment paradigms that were created to rapidly achieve return of spontaneous circulation in the field.

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A porcine model of refractory VF cardiac arrest was developed, including initiation of VF using endovascular occlusion of the proximal LAD followed by 5 min of untreated VF. Resuscitation begins with 10 min of high-quality CPR followed by 35 min of ACLS and reconstitution of coronary flow.

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A 2 × 2 study design was used with animals randomized to use of epinephrine or placebo during ACLS and then again randomized to ECMO or no ECMO at the time of reinitiation of coronary flow.

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ECMO-facilitated coronary reperfusion and hemodynamic stabilization improved 4-h survival compared with CPR-facilitated reperfusion and standard ACLS in a porcine model of refractory VF cardiac arrest.

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Repeated epinephrine boluses provided in accordance with standard ACLS protocols increased systemic blood pressure and coronary perfusion pressure but provided no benefit in survival compared with placebo.

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Over 50% of the animals receiving ECMO met criteria for decannulation at 4 h, suggesting that rapid cardiac and hemodynamic recovery is possible in severely injured animals treated with ECMO.

Extracorporeal membrane oxygenation (ECMO) is used in cardiopulmonary resuscitation (CPR) of refractory cardiac arrest. The authors used a 2 × 2 study design to compare ECMO versus CPR and epinephrine versus placebo in a porcine model of ischemic refractory ventricular fibrillation (VF). Pigs underwent 5 min of untreated VF and 10 min of CPR, and were randomized to receive epinephrine versus placebo for another 35 min. Animals were further randomized to left anterior descending artery (LAD) reperfusion at minute 45 with ongoing CPR versus venoarterial ECMO cannulation at minute 45 of CPR and subsequent LAD reperfusion. Four-hour survival was improved with ECMO whereas epinephrine showed no effect.

Translational cardiac stem cell therapy: advancing from first-generation to next-generation cell types

Acute myocardial infarction and chronic heart failure rank among the major causes of morbidity and mortality worldwide. Except for heart transplantation, current therapy options only treat the symptoms but do not cure the disease. Stem cell-based therapies represent a possible paradigm shift for cardiac repair. However, most of the first-generation approaches displayed heterogeneous clinical outcomes regarding efficacy. Stemming from the desire to closely match the target organ, second-generation cell types were introduced and rapidly moved from bench to bedside. Unfortunately, debates remain around the benefit of stem cell therapy, optimal trial design parameters, and the ideal cell type. Aiming at highlighting controversies, this article provides a critical overview of the translation of first-generation and second-generation cell types. It further emphasizes the importance of understanding the mechanisms of cardiac repair and the lessons learned from first-generation trials, in order to improve cell-based therapies and to potentially finally implement cell-free therapies.

microRNA in Cardiovascular Aging and Age-Related Cardiovascular Diseases

Over the last decades, life expectancy has significantly increased although several chronic diseases persist in the population, with aging as the leading risk factor. Despite improvements in diagnosis and treatment, many elderlies suffer from cardiovascular problems that are much more frequent in an older, more fragile organism. In the long term, age-related cardiovascular diseases (CVDs) contribute to the decline of quality of life and ability to perform normal activities of daily living. microRNAs (miRNAs) are a class of small non-coding RNAs that regulate gene expression at the posttranscriptional level in both physiological and pathological conditions. In this review, we will focus on the role of miRNAs in aging and age-related CVDs as heart failure, hypertension, atherosclerosis, atrial fibrillation, and diabetes mellitus. miRNAs are key regulators of complex biological mechanisms, representing an exciting potential therapeutic target in CVDs. Moreover, one major challenge in geriatric medicine is to find reliable biomarkers for diagnosis, prognosis, and prediction of the response to specific drugs. miRNAs represent a very promising tool due to their stability in the circulation and unique signature in CVDs. However, further studies are needed to investigate their translational potential in the real clinical practice.

microRNA profiling in atherosclerosis, diabetes, and migraine

microRNAs (miRNAs) are a broad group of endogenous small non-coding molecules that reduce the transcription of mRNA and play a key role in post-transcriptional gene processes. miRNAs are involved in onset and progression of several human disorders such as infectious and immune non-infectious diseases, cancers, metabolic and cardiovascular disorders. They regulate the expression of gene targets (e.g. oncogenes and tumor suppressor genes) and act as gene repressors with mRNA binding and cleavage. The increasing evidence that miRNAs play a key role in the pathogenesis of cardiovascular conditions could radically change the future management approach to these disorders. This review focuses on current knowledge about the influence of miRNAs on cardiovascular disease, with particular regard to common conditions such as atherosclerosis, diabetes and migraine. Key messages miRNAs are a group of endogenous small non-coding RNA segments measuring 19-25 nucleotides that are involved in physiologic processes and onset and progression of disorders such as infectious and immune non-infectious diseases, cancers, metabolic and cardiovascular disorders. miRNAs expression guarantees vascular integrity, by regulating apoptosis, VEGF pathway and VCAM 1 expression (-126), and is involved in atherosclerotic plaque formation process and progression. Hyperglycemia, overt diabetes, and their complications are associated with overexpression of several miRNAs. An altered expression of miRNAs has also been postulated in migraine patients, although only a few preliminary studies have so far been performed with this respect.

Regulatory non-coding RNAs in acute myocardial infarction

Acute myocardial infarction (AMI) is one of the most common cardiovascular diseases that leads to high mortality and morbidity globally. Various therapeutic targets for AMI have been investigated in recent years, including the non‐coding RNAs (ncRNAs). NcRNAs, a class of RNA molecules that typically do not code proteins, are divided into several subgroups. Among them, microRNAs (miRNAs) are widely studied for their modulation of several pathological aspects of AMI, including cardiomyocyte apoptosis, inflammation, angiogenesis and fibrosis. It has emerged that long ncRNAs (lncRNAs) and circular RNAs (circRNAs) also regulate these processes via interesting mechanisms. However, the regulatory functions of ncRNAs in AMI and their underlying functional mechanisms have not been systematically described. In this review, we summarize the recent findings involving ncRNA actions in AMI and briefly describe the novel mechanisms of these ncRNAs, highlighting their potential application as therapeutic targets in AMI.

Targeting miR-155 to Treat Experimental Scleroderma

Scleroderma is a refractory autoimmune skin fibrotic disorder. Alterations of microRNAs in lesional skin could be a new approach to treating the disease. Here, we found that expression of miR-155 was up regulated in lesional skin tissue from patients with either systemic or localized scleroderma, and correlated with fibrosis area. Then we demonstrated the potential of miR-155 as a therapeutic target in pre-clinical scleroderma models. MiR-155^−/− mice were resistant to bleomycin induced skin fibrosis. Moreover, topical antagomiR-155 could effectively treat mice primed with subcutaneous bleomycin. In primary skin fibroblast, miR-155 silencing could inhibit collagen synthesis function, as well as signaling intensity of two pro-fibrotic pathways, Wnt/β-catenin and Akt, simultaneously. We further showed that miR-155 could regulate the two pathways via directly targeting casein kinase 1α (CK1α) and Src homology 2-containing inositol phosphatase-1 (SHIP-1), as previous reports. Mice with miR-155 knockout or topical antagomir-155 treatment showed inhibited Wnt/β-catenin and Akt signaling in skin upon bleomycin challenge. Together, our data suggest the potential of miR-155 silencing as a promising treatment for dermal fibrosis, especially in topical applications.

Danshen improves damaged cardiac angiogenesis and cardiac function induced by myocardial infarction by modulating HIF1α/VEGFA signaling pathway

OBJECTIVE

The traditional Chinese medicinal Danshen (Salvia miltiorrhiza), has long been used to treat cardiovascular diseases, however, the mechanism underlying its effects remain unclear. Here, this study would to investigate the effects of Danshen injection on myocardial infarction-induced cardiac damage.

METHODS

Danshen was injected into mice models at low dose (3 g/kg per day) or at high dose (6 g/kg per day) after left anterior descending coronary artery (LAD) ligation. After 4 weeks, cardiac function was evaluated by echocardiography. Paraffin sections of the hearts were used for isolectin GS-IB4 staining. Protein and mRNA expression levels of HIF1α and VEGFA were evaluated by western blotting and real-time polymerase chain reaction (RT-PCR).

RESULTS

The hearts showed significantly impaired angiogenesis and slightly increase of HIF1α and VEGFA expression after LAD ligation. The angiogenesis defect and heart failure were partially rescued in Danshen treatment mice with great increase of HIF1α and VEGFA mRNA levels and protein expression.

CONCLUSION

These results illustrated that the protective effects of Danshen injection in responsive cardiac angiogenesis were at least in part due to increased HIF1α and VEGFA expression.

[MicroRNAs: what cardiologists should know about them?]

MiRNAs are small 21-22 nucleotides long RNAs transcribed from non coding genes or introns of coding genes that are involved the repression of cellular messenger RNAs by the RISC complex. Close to 2000 miRNAs have been identified in the human genome and the expression of hundreds of them is increased or decreased in pathological condition, modifying on a global scale the expression of cardiac and vascular proteins. MiRNAs regulate most cellular processes involved in the cardiovascular pathophysiology including apoptosis, proliferation and migration, left ventricle hypertrophy, cardiac fibrosis and conduction. MiRNAs form a new class of therapeutic targets that can be introduced in the cells in various forms (synthetic molecules, expression vectors) or inhibited by antisens oligonucleotides called anti-miRs. MiRNAs are actively secreted by specific cells including cardiac fibroblasts and endothelial cells during certain pathophysiological processes, or passively following cell death and can be quantified in all kind of body fluids. They emerge as a new category of cardiovascular disease biomarkers, notably in the context of myocardial infarction.