N-acetylglucosamine conjugated to nanoparticles enhances myocyte uptake and improves delivery of a small molecule p38 inhibitor for post-infarct healing

The Role of Antioxidants in the Therapy of Cardiovascular Diseases-A Literature Review

Antioxidants are endogenous and exogenous substances with the ability to inhibit oxidation processes by interacting with reactive oxygen species (ROS). ROS, in turn, are small, highly reactive substances capable of oxidizing a wide range of molecules in the human body, including nucleic acids, proteins, lipids, carbohydrates, and even small inorganic compounds. The overproduction of ROS leads to oxidative stress, which constitutes a significant factor contributing to the development of disease, not only markedly diminishing the quality of life but also representing the most common cause of death in developed countries, namely, cardiovascular disease (CVD). The aim of this review is to demonstrate the effect of selected antioxidants, such as coenzyme Q10 (CoQ10), flavonoids, carotenoids, and resveratrol, as well as to introduce new antioxidant therapies utilizing miRNA and nanoparticles, in reducing the incidence and progression of CVD. In addition, new antioxidant therapies in the context of the aforementioned diseases will be considered. This review emphasizes the pleiotropic effects and benefits stemming from the presence of the mentioned substances in the organism, leading to an overall reduction in cardiovascular risk, including coronary heart disease, dyslipidaemia, hypertension, atherosclerosis, and myocardial hypertrophy.

Nanotechnology: The Future for Diagnostic and Therapeutic Intervention in Cardiovascular Diseases is Here

With advances in technology and medicine over the last 3 decades, cardiovascular medicine has evolved tremendously. Nanotechnology provides a promising future in personalized precision medicine. In this review, we delve into the current and prospective applications of nanotechnology and nanoparticles in cardiology. Nanotechnology has allowed for point-of-care testing such as high-sensitivity troponins, as well as more precise cardiac imaging. This review is focused on 3 diseases within cardiology: coronary artery disease, heart failure, and valvular heart disease. The use of nanoparticles in coronary stents has shown success in preventing in-stent thrombosis, as well as using nanosized drug delivery medications to prevent neointimal proliferation in a way that spares systemic toxicity. In addition, by using nanoparticles as drug delivery systems, nanotechnology can be utilized in the delivery of goal-directed medical therapy in heart failure patients. It has also been shown to improve cell therapy in this patient population by helping in cell retention of grafts. Finally, the use of nanoparticles in the manufacturing of bioprosthetic valves provides a promising future for the longevity and success of cardiac valve repair and replacement.

Microbial production of N-acetyl-D-glucosamine (GlcNAc) for versatile applications: Biotechnological strategies for green process development

N-acetyl-d-glucosamine (GlcNAc) is a commercially important amino sugar for its wide range of applications in pharmaceutical, food, cosmetics and biofuel industries. In nature, GlcNAc is polymerised into chitin biopolymer, which is one of the major constituents of fungal cell wall and outer shells of crustaceans. Sea food processing industries generate a large volume of chitin as biopolymeric waste. Because of its high abundance, chitinaceous shellfish wastes have been exploited as one of the major precursor substrates of GlcNAc production, both in chemical and enzymatic means. Nevertheless, the current process of GlcNAc extraction from shellfish wastes generates poor turnover and attracts environmental hazards. Moreover, GlcNAc isolated from shellfish could not be prescribed to certain groups of people because of the allergic nature of shell components. Therefore, an alternative route of GlcNAc production is advocated. With the advancement of metabolic construction and synthetic biology, microbial synthesis of GlcNAc is gaining much attention nowadays. Several new and cutting-edge technologies like substrate co-utilization strategy, promoter engineering, and CRISPR interference system were proposed in this fascinating area. The study would put forward the potential application of microbial engineering in the production of important pharmaceuticals. Very recently, autotrophic fermentation of GlcNAc synthesis has been proposed. The metabolic engineering approaches would offer great promise to mitigate the issues of low yield and high production cost, which are major challenges in microbial bio-processes industries. Further process optimization, optimising metabolic flux, and efficient recovery of GlcNAc from culture broth, should be investigated in order to achieve a high product titer. The current study presents a comprehensive review on microbe-based eco-friendly green methods that would pave the way towards the development of future research directions in this field for the designing of a cost-effective fermentation process on an industrial setup.

Oxidative stress - Complex pathological issues concerning the hallmark of cardiovascular and metabolic disorders

Oxidative stress is a complex biological process characterized by the excessive production of reactive oxygen species (ROS) that act as destroyers of the REDOX balance in the body and, implicitly, inducing oxidative damage. All the metabolisms are impaired in oxidative stress and even nucleic acid balance is influenced. ROS will promote structural changes of the tissues and organs due to interaction with proteins and phospholipids. The constellation of the cardiovascular risk factors (CVRFs) will usually develop in subjects with predisposition to cardiac disorders. Oxidative stress is usually related with hypertension (HTN), diabetes mellitus (DM), obesity and cardiovascular diseases (CVDs) like coronary artery disease (CAD), cardiomyopathy or heart failure (HF), that can develop in subjects with the above-mentioned diseases. Elements describing the complex relationship between CVD and oxidative stress should be properly explored and described because prevention may be the optimal approach. Our paper aims to expose in detail the complex physiopathology of oxidative stress in CVD occurrence and novelties regarding the phenomenon. Biomarkers assessing oxidative stress or therapy targeting specific pathways represent a major progress that actually change the outcome of subjects with CVD. New antioxidants therapy specific for each CVD represents a captivating and interesting future perspective with tremendous benefits on subject's outcome.

Polymeric nanoparticles in the diagnosis and treatment of myocardial infarction: Challenges and future prospects

Myocardial infarction (MI) is the leading cause of morbidity and mortality worldwide. Despite extensive efforts to provide early diagnosis and adequate treatment regimens, detection of MI still faces major limitations and pathological MI complications continue to threaten the recovery of survivors. Polymeric nanoparticles (NPs) represent novel noninvasive drug delivery systems for the diagnosis and treatment of MI and subsequent prevention of fatal heart failure. In this review, we cover the recent advances in polymeric NP-based diagnostic and therapeutic approaches for MI and their application as multifunctional theranostic tools. We also discuss the in vivo behavior and toxicity profile of polymeric NPs, their application in noninvasive imaging, passive, and active drug delivery, and use in cardiac regenerative therapy. We conclude with the challenges faced with polymeric nanosystems and suggest future efforts needed for clinical translation.

Non-Viral Gene Delivery Systems for Treatment of Myocardial Infarction: Targeting Strategies and Cardiac Cell Modulation

Cardiovascular diseases (CVD) are the leading cause of morbidity and mortality worldwide. Conventional therapies involving surgery or pharmacological strategies have shown limited therapeutic effects due to a lack of cardiac tissue repair. Gene therapy has opened an avenue for the treatment of cardiac diseases through manipulating the underlying gene mechanics. Several gene therapies for cardiac diseases have been assessed in clinical trials, while the clinical translation greatly depends on the delivery technologies. Non-viral vectors are attracting much attention due to their safety and facile production compared to viral vectors. In this review, we discuss the recent progress of non-viral gene therapies for the treatment of cardiovascular diseases, with a particular focus on myocardial infarction (MI). Through a summary of delivery strategies with which to target cardiac tissue and different cardiac cells for MI treatment, this review aims to inspire new insights into the design/exploitation of non-viral delivery systems for gene cargos to promote cardiac repair/regeneration.

Reactive oxygen species-based nanomaterials for the treatment of myocardial ischemia reperfusion injuries

Interventional coronary reperfusion strategies are widely adopted to treat acute myocardial infarction, but morbidity and mortality of acute myocardial infarction are still high. Reperfusion injuries are inevitable due to the generation of reactive oxygen species (ROS) and apoptosis of cardiac muscle cells. However, many antioxidant and anti-inflammatory drugs are largely limited by pharmacokinetics and route of administration, such as short half-life, low stability, low bioavailability, and side effects for treatment myocardial ischemia reperfusion injury. Therefore, it is necessary to develop effective drugs and technologies to address this issue. Fortunately, nanotherapies have demonstrated great opportunities for treating myocardial ischemia reperfusion injury. Compared with traditional drugs, nanodrugs can effectively increase the therapeutic effect and reduces side effects by improving pharmacokinetic and pharmacodynamic properties due to nanodrugs’ size, shape, and material characteristics. In this review, the biology of ROS and molecular mechanisms of myocardial ischemia reperfusion injury are discussed. Furthermore, we summarized the applications of ROS-based nanoparticles, highlighting the latest achievements of nanotechnology researches for the treatment of myocardial ischemia reperfusion injury.

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Cardiovascular diseases are the leading cause of death worldwide. Researches of the myocardial infarction pathology and development of new treatments have very important scientific significance in the biomedical field.

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Many nanomaterials have shown amazing therapeutic effects to reduce myocardial damage by eliminating ROS.

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Nanomaterials effectively reduced myocardial damage through eliminating ROS from NOXs, M-ETC, M-Ca²⁺, M-mPTP, and RIRR.

Advance cardiac nanomedicine by targeting the pathophysiological characteristics of heart failure

Heart failure (HF) has continued to be a leading cause of morbidity and mortality worldwide. Nanomedicine, which can deliver therapeutic drugs/biomolecules specifically to damaged myocardium and overcome the limitations of conventional therapies, shows great potential in the treatment of HF. Although a number of preclinical studies of cardiac nanoformulations have been published, targeted nanomedicine for HF is yet to be applied in clinical practice. Therefore, it is meaningful to sum up past experiences and deepen the understanding of nanomedicine and HF. In this review, we first emphasized the key biological barriers to cardiac nanomedicine that hinder its targeting effect. Since the rational design of nanoparticles should take into account the specific characteristics of HF, we then summarized the key pathophysiological changes of HF to provide a clear understanding on HF, as well as the latest examples of nanotechnology-based delivery strategies for different pathophysiological characteristics. Finally, the major challenges are discussed in detail, aiming to provide guidance for future development of cardiac nanomedicine.

Engineering Carbohydrate-Based Particles for Biomedical Applications: Strategies to Construct and Modify

Carbohydrate-based micro/nanoparticles have gained significant attention for various biomedical applications such as targeted/triggered/controlled drug delivery, bioimaging, biosensing, etc., because of their prominent characteristics like biocompatibility, biodegradability, hydrophilicity, and nontoxicity as well as nonimmunogenicity. Most importantly, the ability of the nanoparticles to recognize specific cell sites by targeting cell surface receptors makes them a promising candidate for designing a targeted drug delivery system. These particles may either comprise polysaccharides/glycopolymers or be integrated with various polymeric/inorganic nanoparticles such as gold, silver, silica, iron, etc., to reduce the toxicity of the inorganic nanoparticles and thus facilitate their cellular insertion. Various synthetic methods have been developed to fabricate carbohydrate-based or carbohydrate-conjugated inorganic/polymeric nanoparticles. In this review, we have highlighted the recently developed synthetic approaches to afford carbohydrate-based particles along with their significance in various biomedical applications.

Oxidative Stress and Antioxidant Treatments in Cardiovascular Diseases

Oxidative stress plays a key role in many physiological and pathological conditions. The intracellular oxidative homeostasis is tightly regulated by the reactive oxygen species production and the intracellular defense mechanisms. Increased oxidative stress could alter lipid, DNA, and protein, resulting in cellular inflammation and programmed cell death. Evidences show that oxidative stress plays an important role in the progression of various cardiovascular diseases, such as atherosclerosis, heart failure, cardiac arrhythmia, and ischemia-reperfusion injury. There are a number of therapeutic options to treat oxidative stress-associated cardiovascular diseases. Well known antioxidants, such as nutritional supplements, as well as more novel antioxidants have been studied. In addition, novel therapeutic strategies using miRNA and nanomedicine are also being developed to treat various cardiovascular diseases. In this article, we provide a detailed description of oxidative stress. Then, we will introduce the relationship between oxidative stress and several cardiovascular diseases. Finally, we will focus on the clinical implications of oxidative stress in cardiovascular diseases.

Nanostructured Polymeric, Liposomal and Other Materials to Control the Drug Delivery for Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the leading cause of death globally, taking an estimated 17.9 million lives each year, representing one third of global mortality. As existing therapies still have limited success, due to the inability to control the biodistribution of the currently approved drugs, the quality of life of these patients is modest. The advent of nanomedicine has brought new insights in innovative treatment strategies. For this reason, several novel nanotechnologies have been developed for both targeted and prolonged delivery of therapeutics to the cardiovascular system tο minimize side effects. In this regard, nanoparticles made of natural and/or synthetic nanomaterials, like liposomes, polymers or inorganic materials, are emerging alternatives for the encapsulation of already approved drugs to control their delivery in a targeted way. Therefore, nanomedicine has attracted the attention of the scientific community as a potential platform to deliver therapeutics to the injured heart. In this review, we discuss the current types of biomaterials that have been investigated as potential therapeutic interventions for CVDs as they open up a host of possibilities for more targeted and effective therapies, as well as minimally invasive treatments.

Nanoscale Technologies for Prevention and Treatment of Heart Failure: Challenges and Opportunities

The adult myocardium has a limited regenerative capacity following heart injury, and the lost cells are primarily replaced by fibrotic scar tissue. Suboptimal efficiency of current clinical therapies to resurrect the infarcted heart results in injured heart enlargement and remodeling to maintain its physiological functions. These remodeling processes ultimately leads to ischemic cardiomyopathy and heart failure (HF). Recent therapeutic approaches (e.g., regenerative and nanomedicine) have shown promise to prevent HF postmyocardial infarction in animal models. However, these preclinical, clinical, and technological advancements have yet to yield substantial enhancements in the survival rate and quality of life of patients with severe ischemic injuries. This could be attributed largely to the considerable gap in knowledge between clinicians and nanobioengineers. Development of highly effective cardiac regenerative therapies requires connecting and coordinating multiple fields, including cardiology, cellular and molecular biology, biochemistry and chemistry, and mechanical and materials sciences, among others. This review is particularly intended to bridge the knowledge gap between cardiologists and regenerative nanomedicine experts. Establishing this multidisciplinary knowledge base may help pave the way for developing novel, safer, and more effective approaches that will enable the medical community to reduce morbidity and mortality in HF patients.

Targeting Oxidative Stress Using Nanoparticles as a Theranostic Strategy for Cardiovascular Diseases

SIGNIFICANCE

Nanomedicine is an application of nanotechnology that provides solutions to unmet medical challenges. The unique features of nanoparticles, such as their small size, modifiable components, and diverse functionality, make them attractive and suitable materials for novel diagnostic, therapeutic, or theranostic applications. Cardiovascular diseases (CVDs) are the major cause of noncommunicable illness in both developing and developed countries. Nanomedicine offers novel theranostic options for the treatment of CVDs. Recent Advances: Many innovative nanoparticles to target reactive oxygen species (ROS) have been developed. In this article, we review the characteristics of nanoparticles that are responsive to ROS, their limitations, and their potential clinical uses. Significant advances made in diagnosis of atherosclerosis and treatment of acute coronary syndrome using nanoparticles are discussed.

CRITICAL ISSUES

Although there is a tremendous potential for the nanoparticle applications in medicine, their safety should be considered while using in humans. We discuss the challenges that may be encountered with some of the innovative nanoparticles used in CVDs.

FUTURE DIRECTIONS

The unique properties of nanoparticles offer novel diagnostic tool and potential therapeutic strategies. However, nanomedicine is still in its infancy, and further in-depth studies are needed before wide clinical application is achieved.

Recent treatment modalities for cardiovascular diseases with a focus on stem cells, aptamers, exosomes and nanomedicine

Cardiovascular diseases (CVDs) are the leading cause of morbidity and mortality worldwide. Due to the significant impact of CVD on humans, there is a need to develop novel treatment modalities tailored to major classes of cardiac diseases including hypertension, coronary artery disease, cardiomyopathies, arrhythmias, valvular disease and inflammatory diseases. In this article, we discuss recent advancements regarding development of therapeutic strategies based on stem cells, aptamers, exosomes, drug-eluting and dissolvable stents, immunotherapy and nanomedicine for the treatment of CVD. We summarize current research and clinical advances in cardiovascular therapeutics, with a focus on therapies that move beyond current oral- or sublingual-based regimens. This review article provides insight into current research and future treatment strategies that hold a great relevance for future clinical practice in pursuit of improving quality of life of patients suffering from CVD.

Cardiac regenerative medicine: At the crossroad of microRNA function and biotechnology

There is an urgent need to develop new therapeutic strategies to stimulate cardiac repair after damage, such as myocardial infarction. Already for more than a century scientist are intrigued by studying the regenerative capacity of the heart. While moving away from the old classification of the heart as a post-mitotic organ, and being inspired by the stem cell research in other scientific fields, mainly three different strategies arose in order to develop regenerative medicine, namely; the use of cardiac stem cells, reprogramming of fibroblasts into cardiomyocytes or direct stimulation of endogenous cardiomyocyte proliferation. MicroRNAs, known to play a role in orchestrating cell fate processes such as proliferation, differentiation and reprogramming, gained a lot of attention in this context the latest years. Indeed, several research groups have independently demonstrated that microRNA-based therapy shows promising results to induce heart tissue regeneration and improve cardiac pump function after myocardial injury. Nowadays, a whole new biotechnology field has been unveiled to investigate the possibilities for efficient, safe and specific delivery of microRNAs towards the heart.

High-throughput screening identifies microRNAs that target Nox2 and improve function after acute myocardial infarction

Myocardial infarction (MI) is the most common cause of heart failure. Excessive production of ROS plays a key role in the pathogenesis of cardiac remodeling after MI. NADPH with NADPH oxidase (Nox)2 as the catalytic subunit is a major source of superoxide production, and expression is significantly increased in the infarcted myocardium, especially by infiltrating macrophages. While microRNAs (miRNAs) are potent regulators of gene expression and play an important role in heart disease, there still lacks efficient ways to identify miRNAs that target important pathological genes for treating MI. Thus, the overall objective was to establish a miRNA screening and delivery system for improving heart function after MI using Nox2 as a critical target. With the use of the miRNA-target screening system composed of a self-assembled cell microarray (SAMcell), three miRNAs, miR-106b, miR-148b, and miR-204, were identified that could regulate Nox2 expression and its downstream products in both human and mouse macrophages. Each of these miRNAs were encapsulated into polyketal (PK3) nanoparticles that could effectively deliver miRNAs into macrophages. Both in vitro and in vivo studies in mice confirmed that PK3-miRNAs particles could inhibit Nox2 expression and activity and significantly improve infarct size and acute cardiac function after MI. In conclusion, our results show that miR-106b, miR-148b, and miR-204 were able to improve heart function after myocardial infarction in mice by targeting Nox2 and possibly altering inflammatory cytokine production. This screening system and delivery method could have broader implications for miRNA-mediated therapeutics for cardiovascular and other diseases.NEW & NOTEWORTHY NADPH oxidase (Nox)2 is a promising target for treating cardiovascular disease, but there are no specific inhibitors. Finding endogenous signals that can target Nox2 and other inflammatory molecules is of great interest. In this study, we used high-throughput screening to identify microRNAs that target Nox2 and improve cardiac function after infarction.

Micro- and Nanoparticles for Treating Cardiovascular Disease

Cardiovascular disease, including myocardial infarction (MI) and peripheral artery disease (PAD), afflicts millions of people in Unites States. Current therapies are insufficient to restore blood flow and repair the injured heart or skeletal muscle, respectively, which is subjected to ischemic damage following vessel occlusion. Micro- and nano-particles are being designed as delivery vehicles for growth factors, enzymes and/or small molecules to provide a sustained therapeutic stimulus at the injured tissue. Depending on the formulation, the particles can be injected directly into the heart or skeletal muscle, or accumulate at the site of injury following an intravenous injection. In this article we review existing particle based therapies for treating MI and PAD.

Formulation and In vitro Interaction of Rhodamine-B Loaded PLGA Nanoparticles with Cardiac Myocytes

This study aims to characterize rhodamine B (Rh B) loaded poly(D,L-lactide-co-glycolide; PLGA) nanoparticles (NPs) and their interactions with cardiac myocytes. PLGA NPs were formulated using single emulsion solvent evaporation technique. The influence of varying parameters such as the stabilizer concentration, the sonication time, and the organic to aqueous ratio were investigated. The diameter, the dispersity, the encapsulation efficiency and the zeta potential of the optimized NPs were about 184 nm, 0.19, 40% and -21.7 mV, respectively. In vitro release showed that 29% of the Rh B was released within the first 8 h. Scanning electron microscopy measurements performed on the optimized NPs showed smooth surface and spherical shapes. No significant cytotoxic or apoptotic effects were observed on cardiac myocytes after 24 and 48 h of exposure with concentrations up to 200 μg/mL. The kinetic of the intracellular uptake was confirmed by confocal microscopy and cells took up PLGA NPs within the 1st hours. Interestingly, our data show an increase in the NPs' uptake with time of exposure. Taken together, we demonstrate for the first time that the designed NPs can be used as potential probes for drug delivery in cardiac myocytes.

Bioinspired negatively charged calcium phosphate nanocarriers for cardiac delivery of MicroRNAs

Aim: To develop biocompatible and bioresorbable negatively charged calcium phosphate nanoparticles (CaP-NPs) as an innovative therapeutic system for the delivery of bioactive molecules to the heart. Materials & methods: CaP-NPs were synthesized via a straightforward one-pot biomineralization-inspired protocol employing citrate as a stabilizing agent and regulator of crystal growth. CaP-NPs were administered to cardiac cells in vitro and effects of treatments were assessed. CaP-NPs were administered in vivo and delivery of microRNAs was evaluated. Results: CaP-NPs efficiently internalized into cardiomyocytes without promoting toxicity or interfering with any functional properties. CaP-NPs successfully encapsulated synthetic microRNAs, which were efficiently delivered into cardiac cells in vitro and in vivo. Conclusion: CaP-NPs are a safe and efficient drug-delivery system for potential therapeutic treatments of polarized cells such as cardiomyocytes.

Nanomedicines for Endothelial Disorders

The endothelium lines the internal surfaces of blood and lymphatic vessels and has a critical role in maintaining homeostasis. Endothelial dysfunction is involved in the pathology of many diseases and conditions, including disorders such as diabetes, cardiovascular diseases, and cancer. Given this common etiology in a range of diseases, medicines targeting an impaired endothelium can strengthen the arsenal of therapeutics. Nanomedicine - the application of nanotechnology to healthcare - presents novel opportunities and potential for the treatment of diseases associated with an impaired endothelium. This review discusses therapies currently available for the treatment of these disorders and highlights the application of nanomedicine for the therapy of these major disease complications.

Bioactive nanoparticles improve calcium handling in failing cardiac myocytes

AIMS

To evaluate the ability of N-acetylglucosamine (GlcNAc) decorated nanoparticles and their cargo to modulate calcium handling in failing cardiac myocytes (CMs).

MATERIALS & METHODS

Primary CMs isolated from normal and failing hearts were treated with GlcNAc nanoparticles in order to assess the ability of the nanoparticles and their cargo to correct dysfunctional calcium handling in failing myocytes.

RESULTS & CONCLUSION

GlcNAc particles reduced aberrant calcium release in failing CMs and restored sarcomere function. Additionally, encapsulation of a small calcium-modulating protein, S100A1, in GlcNAc nanoparticles also showed improved calcium regulation. Thus, the development of our bioactive nanoparticle allows for a 'two-hit' treatment, by which the cargo and also the nanoparticle itself can modulate intracellular protein activity.

p38 MAPK in cardioprotection - are we there yet?

PKs transfer a phosphate from ATP to the side-chain hydroxyl group of a serine, threonine or tyrosine residue of a substrate protein. This in turn can alter that protein's function; modulating fundamental cellular processes including, metabolism, transcription, growth, division, differentiation, motility and survival. PKs are subdivided into families based on homology. One such group are the stress-activated kinases, which as the name suggests, are activated in response to cellular stresses such as toxins, cytokines, mechanical deformation and osmotic stress. Members include the p38 MAPK family, which is composed of α, β, γ and δ, isoforms which are encoded by separate genes. These kinases transduce extracellular signals and coordinate the cellular responses needed for adaptation and survival. However, in cardiovascular and other disease states, these same systems can trigger maladaptive responses that aggravate, rather than alleviate, the disease. This situation is analogous to adrenergic, angiotensin and aldosterone signalling in heart failure, where inhibition is beneficial despite the importance of these hormones to homeostasis. The question is whether similar benefits could accrue from p38 inhibition? In this review, we will discuss the structure and function of p38, the history of p38 inhibitors and their use in preclinical studies. Finally, we will summarize the results of recent cardiovascular clinical trials with p38 inhibitors.

Ceria nanoparticles stabilized by organic surface coatings activate the lysosome-autophagy system and enhance autophagic clearance

Cerium oxide nanoparticles (nanoceria) are widely used in a variety of industrial applications including UV filters and catalysts. The expanding commercial scale production and use of ceria nanoparticles have inevitably increased the risk of release of nanoceria into the environment as well as the risk of human exposure. The use of nanoceria in biomedical applications is also being currently investigated because of its recently characterized antioxidative properties. In this study, we investigated the impact of ceria nanoparticles on the lysosome-autophagy system, the main catabolic pathway that is activated in mammalian cells upon internalization of exogenous material. We tested a battery of ceria nanoparticles functionalized with different types of biocompatible coatings (N-acetylglucosamine, polyethylene glycol and polyvinylpyrrolidone) expected to have minimal effect on lysosomal integrity and function. We found that ceria nanoparticles promote activation of the transcription factor EB, a master regulator of lysosomal function and autophagy, and induce upregulation of genes of the lysosome-autophagy system. We further show that the array of differently functionalized ceria nanoparticles tested in this study enhance autophagic clearance of proteolipid aggregates that accumulate as a result of inefficient function of the lysosome-autophagy system. This study provides a mechanistic understanding of the interaction of ceria nanoparticles with the lysosome-autophagy system and demonstrates that ceria nanoparticles are activators of autophagy and promote clearance of autophagic cargo. These results provide insights for the use of nanoceria in biomedical applications, including drug delivery. These findings will also inform the design of engineered nanoparticles with safe and precisely controlled impact on the environment and the design of nanotherapeutics for the treatment of diseases with defective autophagic function and accumulation of lysosomal storage material.

Dysregulation of catalase activity in newborn myocytes during hypoxia is mediated by c-Abl tyrosine kinase

In the adult heart, catalase (CAT) activity increases appropriately with increasing levels of hydrogen peroxide, conferring cardioprotection. This mechanism is absent in the newborn for unknown reasons. In the present study, we examined how the posttranslational modification of CAT contributes to its activation during hypoxia/ischemia and the role of c-Abl tyrosine kinase in this process. Hypoxia studies were carried out using primary cardiomyocytes from adult (>8 weeks) and newborn rats. Following hypoxia, the ratio of phosphorylated to total CAT and c-Abl in isolated newborn rat myocytes did not increase and were significantly lower (1.3- and 4.2-fold, respectively; P < .05) than their adult counterparts. Similarly, there was a significant association (P < .0005) between c-Abl and CAT in adult cells following hypoxia (30.9 ± 8.2 to 70.7 ± 13.1 au) that was absent in newborn myocytes. Although ubiquitination of CAT was higher in newborns compared to adults following hypoxia, inhibition of this did not improve CAT activity. When a c-Abl activator (5-(1,3-diaryl-1H-pyrazol-4-yl)hydantoin [DPH], 200 µmol/L) was administered prior to hypoxia, not only CAT activity was significantly increased (P < .05) but also phosphorylation levels were also significantly improved (P < .01) in these newborn myocytes. Additionally, ischemia-reperfusion (IR) studies were performed using newborn (4-5 days) rabbit hearts perfused in a Langendorff method. The DPH given as an intracardiac injection into the right ventricle of newborn rabbit resulted in a significant improvement (P < .002) in the recovery of developed pressure after IR, a key indicator of cardiac function (from 74.6% ± 6.6% to 118.7% ± 10.9%). In addition, CAT activity was increased 3.92-fold (P < .02) in the same DPH-treated hearts. Addition of DPH to adult rabbits in contrast had no significant effect (from 71.3% ± 10.7% to 59.4% ± 12.1%). Therefore, in the newborn, decreased phosphorylation of CAT by c-Abl potentially mediates IR-induced dysfunction, and activation of c-Abl may be a strategy to prevent ischemic injury associated with surgical procedures.

Delivery of Nox2-NADPH oxidase siRNA with polyketal nanoparticles for improving cardiac function following myocardial infarction

Myocardial infarction (MI) is the most common cause of heart failure (HF), the leading cause of death in the developed world. Oxidative stress due to excessive production of reactive oxygen species (ROS) plays a key role in the pathogenesis of cardiac remodeling leading to HF. NADPH oxidase with Nox2 as the catalytic subunit is a major source for cardiac ROS production. Nox2-NADPH expression is significantly increased in the infarcted myocardium, primarily in neutrophils, macrophages and myocytes. Moreover, mice lacking the Nox2 gene are protected from ischemic injury, implicating Nox2 as a potential therapeutic target. RNAi-mediated gene silencing holds great promise as a therapeutic owing to its high specificity and potency. However, in vivo delivery hurdles have limited its effective clinical use. Here, we demonstrate acid-degradable polyketal particles as delivery vehicles for Nox2-siRNA to the post-MI heart. In vitro, Nox2-siRNA particles are effectively taken up by macrophages and significantly knockdown Nox2 expression and activity. Following in vivo intramyocardial injection in experimental mice models of MI, Nox2-siRNA particles prevent upregulation of Nox2 and significantly recovered cardiac function. This study highlights the potential of polyketals as siRNA delivery vehicles to the MI heart and represents a viable therapeutic approach for targeting oxidative stress.

Induction of pluripotency in bone marrow mononuclear cells via polyketal nanoparticle-mediated delivery of mature microRNAs

Since the successful generation of induced pluripotent stem cells (iPSC) from adult somatic cells using integrating-viral methods, various methods have been tried for iPSC generation using non-viral and non-integrating technique for clinical applications. Recently, various non-viral approaches such as protein, mRNA, microRNA, and small molecule transduction were developed to avoid genomic integration and generate stem cell-like cells from mouse and human fibroblasts. Despite these successes, there has been no successful generation of iPSC from bone marrow (BM)-derived hematopoietic cells derived using non-viral methods to date. Previous reports demonstrate the ability of polymeric micro and nanoparticles made from polyketals to deliver various molecules to macrophages. MicroRNA-loaded nanoparticles were created using the polyketal polymer PK3 (PK3-miR) and delivered to somatic cells for 6 days, resulting in the formation of colonies. Isolated cells from these colonies were assayed and substantial induction of the pluripotency markers Oct4, Sox2, and Nanog were detected. Moreover, colonies transferred to feeder layers also stained positive for pluripotency markers including SSEA-1. Here, we demonstrate successful activation of pluripotency-associated genes in mouse BM-mononuclear cells using embryonic stem cell (ESC)-specific microRNAs encapsulated in the acid sensitive polyketal PK3. These reprogramming results demonstrate that a polyketal-microRNA delivery vehicle can be used to generate various reprogrammed cells without permanent genetic manipulation in an efficient manner.

Functionalized dendrimer-based delivery of angiotensin type 1 receptor siRNA for preserving cardiac function following infarction

Cardiovascular disease (CVD) is the leading cause of death throughout the world and much pathology is associated with upregulation of inflammatory genes. Gene silencing using RNA interference is a powerful tool in regulating gene expression, but its application in CVDs has been prevented by the lack of efficient delivery systems. We report here the development of tadpole dendrimeric materials for siRNA delivery in a rat ischemia-reperfusion (IR) model. Angiotensin II (Ang II) type 1 receptor (AT1R), the major receptor that mediates most adverse effects of Ang II, was chosen to be the silencing targeting. Among the three tadpole dendrimers synthesized, the oligo-arginine conjugated dendrimer loaded with siRNA demonstrated effective down-regulation in AT1R expression in cardiomyocytes in vitro. When the dendrimeric material was applied in vivo, the siRNA delivery prevented the increase in AT1R levels and significantly improved cardiac function recovery compared to saline injection or empty dendrimer treated groups after IR injury. These experiments demonstrate a potential treatment for dysfunction caused by IR injury and may represent an alternative to AT1R blockade.