Anti-VCAM-1 and Anti-E-selectin SAINT-O-Somes for Selective Delivery of siRNA into Inflammation-Activated Primary Endothelial Cells

MC3/SAINT-O-Somes, a novel liposomal delivery system for efficient and safe delivery of siRNA into endothelial cells

Increased understanding of chronic inflammatory diseases and the role of endothelial cell (EC) activation herein, have urged interest in sophisticated strategies to therapeutically intervene in activated EC to treat these diseases. Liposome-mediated delivery of therapeutic siRNA in inflammation-activated EC is such a strategy. In this study, we describe the design and characterisation of two liposomal siRNA delivery systems formulated with the cationic MC3 lipid or MC3/SAINT mixed lipids, referred to as MC3-O-Somes (MOS) and MC3/SAINT-O-Somes (MSS). The two formulations showed comparable physicochemical properties, except for better siRNA encapsulation efficiency in the MSS formulation. Antibody-mediated VCAM-1 targeting (AbVCAM-1) increased the association of the targeted MOS and MSS with activated EC, although the targeted MOS showed a significantly higher VCAM-1 specific association than the targeted MSS. AbVCAM-1 MSS containing RelA siRNA achieved significant downregulation of RelA expression, while AbVCAM-1 MOS containing RelA siRNA did not downregulate RelA expression in activated EC. Additionally, AbVCAM-1 MSS containing RelA siRNA showed low cytotoxicity in EC and at the same time prohibited endothelial inflammatory activation by reducing expression of cell adhesion molecules. The AbVCAM-1 MSS formulation is a novel siRNA delivery system based on a combination of the cationic lipids MC3 and SAINT, that shows good physicochemical characteristics, enhanced endothelial cell association, improved transfection activity, low toxicity and significant anti-inflammatory effect, thereby complying with the requirements for future in vivo investigations.

Nanomedicines for the management of diabetic nephropathy: present progress and prospects

Diabetic nephropathy (DN) is a serious microvascular consequence of diabetes mellitus (DM), posing an encumbrance to public health worldwide. Control over the onset and progress of DN depend heavily on early detection and effective treatment. DN is a major contributor to end-stage renal disease, and a complete cure is yet to be achieved with currently available options. Though some therapeutic molecules have exhibited promise in treating DN complications, their poor solubility profile, low bioavailability, poor permeation, high therapeutic dose and associated toxicity, and low patient compliance apprehend their clinical usefulness. Recent research has indicated nano-systems as potential theranostic platforms displaying futuristic promise in the diagnosis and treatment of DN. Early and accurate diagnosis, site-specific delivery and retention by virtue of ligand conjugation, and improved pharmacokinetic profile are amongst the major advantages of nano-platforms, defining their superiority. Thus, the emergence of nanoparticles has offered fresh approaches to the possible diagnostic and therapeutic strategies regarding DN. The present review corroborates an updated overview of different types of nanocarriers regarding potential approaches for the diagnosis and therapy of DN.

Biomimetic nanomedicines for precise atherosclerosis theranostics

Atherosclerosis (AS) is a leading cause of the life-threatening cardiovascular disease (CVD), creating an urgent need for efficient, biocompatible therapeutics for diagnosis and treatment. Biomimetic nanomedicines (bNMs) are moving closer to fulfilling this need, pushing back the frontier of nano-based drug delivery systems design. This review seeks to outline how these nanomedicines (NMs) might work to diagnose and treat atherosclerosis, to trace the trajectory of their development to date and in the coming years, and to provide a foundation for further discussion about atherosclerotic theranostics.

Advances in drug delivery to atherosclerosis: Investigating the efficiency of different nanomaterials employed for different type of drugs

Atherosclerosis is the build-up of fatty deposits in the arteries, which is the main underlying cause of cardiovascular diseases and the leading cause of global morbidity and mortality. Current pharmaceutical treatment options are unable to effectively treat the plaque in the later stages of the disease. Instead, they are aimed at resolving the risk factors. Nanomaterials and nanoparticle-mediated therapies have become increasingly popular for the treatment of atherosclerosis due to their targeted and controlled release of therapeutics. In this review, we discuss different types of therapeutics used to treat this disease and focus on the different nanomaterial strategies employed for the delivery of these drugs, enabling the effective and efficient resolution of the atherosclerotic plaque. The ideal nanomaterial strategy for each drug type (e.g. statins, nucleic acids, small molecule drugs, peptides) will be comprehensively discussed.

The emerging potential of siRNA nanotherapeutics in treatment of arthritis

RNA interference (RNAi) using small interfering RNA (siRNA) has shown potential as a therapeutic option for the treatment of arthritis by silencing specific genes. However, siRNA delivery faces several challenges, including stability, targeting, off-target effects, endosomal escape, immune response activation, intravascular degradation, and renal clearance. A variety of nanotherapeutics like lipidic nanoparticles, liposomes, polymeric nanoparticles, and solid lipid nanoparticles have been developed to improve siRNA cellular uptake, protect it from degradation, and enhance its therapeutic efficacy. Researchers are also investigating chemical modifications and bioconjugation to reduce its immunogenicity. This review discusses the potential of siRNA nanotherapeutics as a therapeutic option for various immune-mediated diseases, including rheumatoid arthritis, osteoarthritis, etc. siRNA nanotherapeutics have shown an upsurge of interest and the future looks promising for such interdisciplinary approach-based modalities that combine the principles of molecular biology, nanotechnology, and formulation sciences.

Targeted delivery of nutraceuticals derived from food for the treatment of obesity and its related complications

Nutraceuticals which are abundant in foods have attracted much attention due to their bioactive activities of anti-obesity, anti-hyperlipidemia and anti-atherosclerosis. Unfortunately, the poor bioavailability severely undermines their envisioned benefits. Therefore, there is an urgent need to develop suitable delivery systems to promote the benefits of their biological activity. Targeted drug delivery system (TDDS) is a novel drug delivery system that can selectively concentrate drugs on targets in the body, improve the bioavailability of agents and reduce side effects. This emerging drug delivery system provides a new strategy for the treatment of obesity with nutraceuticals and would be a promising alternative to be widely used in the food field. This review summarizes the recent studies on the application in the targeted delivery of nutraceuticals for treating obesity and its related complications, especially the available receptors and their corresponding ligands for TDDS and the evaluation methods of the targeting ability.

MiR-146a encapsulated liposomes reduce vascular inflammatory responses through decrease of ICAM-1 expression, macrophage activation, and foam cell formation

Vascular insults can create an inflammatory cascade involving endothelial cell, smooth muscle cell, and macrophage activation which can eventually lead to vascular disease such as atherosclerosis. Several studies have identified microRNA 146a's (miR-146a) anti-inflammatory potential based on its role in regulating the nuclear factor kappa beta (NF-κβ) pathway. Therefore, in this study, we introduced exogenous miR-146a encapsulated by liposomes to lipopolysaccharide (LPS) stimulated vascular cells and macrophages to reduce inflammatory responses. First, the miR-146a encapsulated liposomes showed uniform size (radius 96.4 ± 4.22 nm) and round shape, long term stability (at least two months), high encapsulation efficiency (69.73 ± 0.07%), and were well transfected to human aortic endothelial cells (HAECs), human aortic smooth muscle cells (SMCs), and human differentiated monocytes (U937 cells). In addition, we demonstrated that miR-146a encapsulated liposomes reduced vascular inflammation responses in HAECs and SMCs through inhibition of ICAM-1 expression and decreased monocyte adhesion. In macrophages, miR-146a liposome treatment demonstrated decreased production of proinflammatory cytokines, tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β), as well as reduced oxidized low-density lipoprotein (ox-LDL) uptake and foam cell formation. Thus, based on these results, miR-146a encapsulated liposomes may be promising for reducing vascular inflammation by targeting its multiple associated mediators.

Vaccine Formulation Strategies and Challenges Involved in RNA Delivery for Modulating Biomarkers of Cardiovascular Diseases: A Race from Laboratory to Market

It has been demonstrated that noncoding RNAs have significant physiological and pathological roles. Modulation of noncoding RNAs may offer therapeutic approaches as per recent findings. Small RNAs, mostly long noncoding RNAs, siRNA, and microRNAs make up noncoding RNAs. Inhibiting or promoting protein breakdown by binding to 3' untranslated regions of target mRNA, microRNAs post-transcriptionally control the pattern of gene expression. Contrarily, long non-coding RNAs perform a wider range of tasks, including serving as molecular scaffolding, decoys, and epigenetic regulators. This article provides instances of long noncoding RNAs and microRNAs that may be a biomarker of CVD (cardiovascular disease). In this paper we highlight various RNA-based vaccine formulation strategies designed to target these biomarkers-that are either currently in the research pipeline or are in the global pharmaceutical market-along with the physiological hurdles that need to be overcome.

Endothelial Cell Adhesion Molecules- (un)Attainable Targets for Nanomedicines

Endothelial cell adhesion molecules have long been proposed as promising targets in many pathologies. Despite promising preclinical data, several efforts to develop small molecule inhibitors or monoclonal antibodies (mAbs) against cell adhesion molecules (CAMs) ended in clinical-stage failure. In parallel, many well-validated approaches for targeting CAMs with nanomedicine (NM) were reported over the years. A wide range of potential applications has been demonstrated in various preclinical studies, from drug delivery to the tumor vasculature, imaging of the inflamed endothelium, or blocking immune cells infiltration. However, no NM drug candidate emerged further into clinical development. In this review, we will summarize the most advanced examples of CAM-targeted NMs and juxtapose them with known traditional drugs against CAMs, in an attempt to identify important translational hurdles. Most importantly, we will summarize the proposed strategies to enhance endothelial CAM targeting by NMs, in an attempt to offer a catalog of tools for further development.

Lipids and Lipid Derivatives for RNA Delivery

RNA-based therapeutics have shown great promise in treating a broad spectrum of diseases through various mechanisms including knockdown of pathological genes, expression of therapeutic proteins, and programmed gene editing. Due to the inherent instability and negative-charges of RNA molecules, RNA-based therapeutics can make the most use of delivery systems to overcome biological barriers and to release the RNA payload into the cytosol. Among different types of delivery systems, lipid-based RNA delivery systems, particularly lipid nanoparticles (LNPs), have been extensively studied due to their unique properties, such as simple chemical synthesis of lipid components, scalable manufacturing processes of LNPs, and wide packaging capability. LNPs represent the most widely used delivery systems for RNA-based therapeutics, as evidenced by the clinical approvals of three LNP-RNA formulations, patisiran, BNT162b2, and mRNA-1273. This review covers recent advances of lipids, lipid derivatives, and lipid-derived macromolecules used in RNA delivery over the past several decades. We focus mainly on their chemical structures, synthetic routes, characterization, formulation methods, and structure-activity relationships. We also briefly describe the current status of representative preclinical studies and clinical trials and highlight future opportunities and challenges.

Recent Advances in Liposomal-Based Anti-Inflammatory Therapy

Liposomes can be seen as ideal carriers for anti-inflammatory drugs as their ability to (passively) target sites of inflammation and release their content to inflammatory target cells enables them to increase local efficacy with only limited systemic exposure and adverse effects. Nonetheless, few liposomal formulations seem to reach the clinic. The current review provides an overview of the more recent innovations in liposomal treatment of rheumatoid arthritis, psoriasis, vascular inflammation, and transplantation. Cutting edge developments include the liposomal delivery of gene and RNA therapeutics and the use of hybrid systems where several liposomal bilayer features, or several drugs, are combined in a single formulation. The majority of the articles reviewed here focus on preclinical animal studies where proof-of-principle of an improved efficacy-safety ratio is observed when using liposomal formulations. A few clinical studies are included as well, which brings us to a discussion about the challenges of clinical translation of liposomal nanomedicines in the field of inflammatory diseases.

Anti-Vascular Cell Adhesion Molecule-1 Nanosystems: A Promising Strategy Against Inflammatory Based Diseases

Inflammation underlays the onset and supports the development of several worldwide diffused pathologies, therefore in the last decades inflammatory markers have attracted a great deal of interest as diagnostic and therapeutic targets. Adhesion molecules are membrane proteins expressed by endotheliocytes and leukocytes, acting as mediators in the process of tethering, rolling, firm adhesion and diapedesis that leads the immune cells to reach an inflamed tissue. Among them, the adhesion molecule VCAM-1 has been investigated as a potential target because of its low constitutive expression and easy accessibility on the endothelium. Moreover, VCAM-1 is involved in the early stages of development of several pathologies like, among others, atherosclerosis, cancer, Alzheimer's and Parkinson's diseases, so a diagnostic or therapeutic tool directed to this protein would allow specific detection and efficacious intervention. The availability of monoclonal antibodies against VCAM-1 has recently fostered the development of various targeting technologies potentially suitable for imaging and drug delivery in VCAM-1 overexpressing pathologies. In this review we initially focus on the structure and functions of VCAM-1, giving also a brief overview of antibodies origin, structure and function; then, we summarize some of the VCAM-1 targeting nanosystems based on antibodies, gathered according to the carrier used, for diagnosis or therapeutic treatment of different inflammatory based pathologies.

Atherosclerosis and Nanomedicine Potential: Current Advances and Future Opportunities

Atherosclerosis is the leading inducement of cardiovascular diseases, which ranks the first cause of global deaths. It is an arterial disease associated with dyslipidemia and changes in the composition of the vascular wall. Besides invasive surgical strategy, the current conservative clinical treatment for atherosclerosis falls into two categories, lipid regulating-based therapy and antiinflammatory therapy. However, the existing strategies based on conventional drug delivery systems have shown limited efficacy against disease development and plenty of side effects. Nanomedicine has great potential in the development of targeted therapy, controlled drug delivery and release, the design of novel specific drugs and diagnostic modalities, and biocompatible scaffolds with multifunctional characteristics, which has led to an evolution in the diagnosis and treatment of atherosclerosis. This paper will focus on the latest nanomedicine strategies for atherosclerosis diagnosis and treatment as well as discussing the potential therapeutic targets during atherosclerosis progress, which could form the basis of development of novel nanoplatform against atherosclerosis.

Effect of endothelial cell heterogeneity on nanoparticle uptake

Endothelial cells exhibit distinct properties in morphology and functions in different organs that can be exploited for nanomedicine targeting. In this work, endothelial cells from different organs, i.e. brain, lung, liver, and kidney, were exposed to plain, carboxylated, and amino-modified silica. As expected, different protein coronas were formed on the different nanoparticle types and these changed when foetal bovine serum (FBS) or human serum were used. Uptake efficiencies differed strongly in the different endothelia, confirming that the cells retained some of their organ-specific differences. However, all endothelia showed higher uptake for the amino-modified silica in FBS, but, interestingly, this changed to the carboxylated silica when human serum was used, confirming that differences in the protein corona affect uptake preferences by cells. Thus, uptake rates of fluid phase markers and transferrin were determined in liver and brain endothelium to compare their endocytic activity. Overall, our results showed that endothelial cells of different organs have very different nanoparticle uptake efficiency, likely due to differences in receptor expression, affinity, and activity. A thorough characterization of phenotypic differences in the endothelia lining different organs is key to the development of targeted nanomedicine.

Recent Advances in Nanotheranostics for Treat-to-Target of Rheumatoid Arthritis

Early diagnosis, standardized treatment, and regular monitoring are the clinical treatment principle of rheumatoid arthritis (RA). The overarching principles and recommendations of treat-to-target (T2T) in RA advocate remission as the optimum aim, especially for patients with very early disease who are initiating therapy with anti-RA medications. However, traditional anti-RA drugs cannot selectively target the inflammatory areas and may cause serious side effects due to its short biological half-life and poor bioavailability. These limitations have significantly driven the research and application of nanomaterial-based drugs in theranostics of RA. Nanomedicines have appropriate sizes and easily modified surfaces which can enhance their biological compatibility and prolong circulation time of drug-loading systems in vivo. Traditional T2T regimens cannot evaluate the efficacy of drugs in real time, while clinical drug nanosizing can realize the integration of diagnosis and treatment of RA. This review bridges clinically proposed T2T concepts and nanomedicine in an integrated system for RA early-stage diagnosis and treatment. The most advanced progress in various nanodrug delivery systems for theranostics of RA is summarized, establishing a clear path and a new perspective for further optimization of T2T. Finally, the key facing challenges are discussed and prospects are addressed.

Understanding molecular upsets in diabetic nephropathy to identify novel targets and treatment opportunities

Diabetes and related complications are becoming a global encumbrance. Diabetic nephropathy (DN) is a major cause of end-stage renal disease (ESRD). The available therapeutic modalities related to DN do not treat DN at the molecular level, proposing further amendments in the management of DN based on the pathogenesis of DN. This manuscript discusses the concept and applications of nanomedicine for the treatment of DN that can improve renal targeting, retention and localization. This review also highlights the current issues related to targeting DN, challenges and allied opportunities toward the development of next-generation drugs and treatments for the management of DN.

A new approach to the diagnosis and treatment of atherosclerosis: the era of the liposome

The consequences of atherosclerotic cardiovascular disease (ASCVD) include myocardial infarction, ischemic stroke, and angina pectoris, which are major causes of mortality and morbidity worldwide. Despite current therapeutic strategies to reduce risk, patients still experience the consequences of ASCVD. Consequently, a current goal is to enhance visualization of early atherosclerotic lesions to improve residual ASCVD risk. The uses of liposomes, in the context of ASCVD, can include as contrast agents for imaging techniques, as well as for the delivery of antiatherosclerotic drugs, genes, and cells to established sites of plaque. Additionally, liposomes have a role as vaccine adjuvants against mediators of atherosclerosis. Here. we review the scientific and clinical evidence relating to the use of liposomes in the diagnosis and management of ASCVD.

Targeting Early Atherosclerosis: A Focus on Oxidative Stress and Inflammation

Atherosclerosis is a chronic vascular inflammatory disease associated to oxidative stress and endothelial dysfunction. Oxidation of low-density lipoprotein (LDL) cholesterol is one of the key factors for the development of atherosclerosis. Nonoxidized LDL have a low affinity for macrophages, so they are not themselves a risk factor. However, lowering LDL levels is a common clinical practice to reduce oxidation and the risk of major events in patients with cardiovascular diseases (CVD). Atherosclerosis starts with dysfunctional changes in the endothelium induced by disturbed shear stress which can lead to endothelial and platelet activation, adhesion of monocytes on the activated endothelium, and differentiation into proinflammatory macrophages, which increase the uptake of oxidized LDL (oxLDL) and turn into foam cells, exacerbating the inflammatory signalling. The atherosclerotic process is accelerated by a myriad of factors, such as the release of inflammatory chemokines and cytokines, the generation of reactive oxygen species (ROS), growth factors, and the proliferation of vascular smooth muscle cells. Inflammation and immunity are key factors for the development and complications of atherosclerosis, and therefore, the whole atherosclerotic process is a target for diagnosis and treatment. In this review, we focus on early stages of the disease and we address both biomarkers and therapeutic approaches currently available and under research.

Targeted Transfection Using PEGylated Cationic Liposomes Directed Towards P-Selectin Increases siRNA Delivery into Activated Endothelial Cells

: The progress in small-interfering RNA (siRNA) therapeutics depends on the development of suitable nanocarriers to perform specific and effective delivery to dysfunctional cells. In this paper, we questioned whether P-selectin, a cell adhesion molecule specifically expressed on the surface of activated endothelial cells (EC) could be employed as a target for nanotherapeutic intervention. To this purpose, we developed and characterized P-selectin targeted PEGylated cationic liposomes able to efficiently pack siRNA and to function as efficient vectors for siRNA delivery to tumour necrosis factor-α (TNF-α) activated EC. Targeted cationic liposomes were obtained by coupling a peptide with high affinity for P-selectin to a functionalized PEGylated phospholipid inserted in the liposomes' bilayer (Psel-lipo). As control, scrambled peptide coupled cationic liposomes (Scr-lipo) were used. The lipoplexes obtained by complexation of Psel-lipo with siRNA (Psel-lipo/siRNA) were taken up specifically and at a higher extent by TNF-α activated b.End3 endothelial cells as compared to non-targeted Scr-lipo/siRNA. The Psel-lipo/siRNA delivered with high efficiency siRNA into the cells. The lipoplexes were functional as demonstrated by the down-regulation of the selected gene (GAPDH). The results demonstrate an effective targeted delivery of siRNA into cultured activated endothelial cells using P-selectin directed PEGylated cationic liposomes, which subsequently knock-down the desired gene.

Endothelium-targeted delivery of dexamethasone by anti-VCAM-1 SAINT-O-Somes in mouse endotoxemia

Microvascular endothelial cells play a pivotal role in the pathogenesis of sepsis-induced inflammatory responses and multiple organ failure. Therefore, they represent an important target for pharmacological intervention in the treatment of sepsis. Glucocorticosteroids were widely used in the treatment of sepsis but vast evidence to support their systemic use is lacking. The limited effects of glucocorticoids in the treatment of sepsis may be explained by differential effects of drug initiated NF-κB inhibition in different cell types and insufficient drug delivery in target cells. The current study aimed therefore to investigate the effects of an endothelial targeted delivery of dexamethasone in a mouse model of endotoxemia induced by two consecutive i.p. injections of lipopolysaccharide (LPS). To achieve endothelial cell specific delivery of dexamethasone, we modified SAINT-O-Somes, a new generation of liposomes that contain the cationic amphiphile SAINT-C18 (1-methyl-4-(cis-9-dioleyl) methyl-pyridinium chloride, with antibodies against vascular cell adhesion molecule-1 (VCAM-1). In LPS challenged mice, the systemic administration of free dexamethasone had negligible effects on the microvascular inflammatory endothelial responses. Dexamethasone-loaded anti-VCAM-1 SAINT-O-Somes specifically localized at VCAM-1 expressing endothelial cells in the microvasculature of inflamed organs. This was associated with a marginal attenuation of the expression of a few pro-inflammatory genes in kidney and liver, while no effects in the lung were observed. This study reveals that, although local accumulation of the targeted drug was achieved, endothelial targeted dexamethasone containing anti-VCAM-1 SAINT-O-Somes exhibited marginal effects on inflammatory endothelial cell activation in a model of endotoxemia. Studies with more potent drugs encapsulated into anti-VCAM-1 SAINT-O-Somes will in the future reveal whether this delivery system can be further developed for efficacious endothelial directed delivery of drugs in the treatment of sepsis.

Combating atherosclerosis with targeted nanomedicines: recent advances and future prospective

Introduction: Cardiovascular diseases (CVDs) is recognized as the leading cause of mortality worldwide. The increasing prevalence of such disease demands novel therapeutic and diagnostic approaches to overcome associated clinical/social issues. Recent advances in nanotechnology and biological sciences have provided intriguing insights to employ targeted Nanomachines to the desired location as imaging, diagnosis, and therapeutic modalities. Nanomedicines as novel tools for enhanced drug delivery, imaging, and diagnosis strategies have shown great promise to combat cardiovascular diseases.

Methods: In the current study, we intend to review the most recent studies on the nano-based strategies for improved management of CVDs.

Results: A cascade of events results in the formation of atheromatous plaque and arterial stenosis. Furthermore, recent studies have shown that nanomedicines have displayed unique functionalities and provided de novo applications in the diagnosis and treatment of atherosclerosis.

Conclusion: Despite some limitations, nanomedicines hold considerable potential in the prevention, diagnosis, and treatment of various ailments including atherosclerosis. Fewer side effects, amenable physicochemical properties and multi-potential application of such nano-systems are recognized through various investigations. Therefore, it is strongly believed that with targeted drug delivery to atherosclerotic lesions and plaque, management of onset and progression of disease would be more efficient than classical treatment modalities.

Oxidative Stress in Atherosclerosis

PURPOSE OF REVIEW

Atherosclerosis is now considered a chronic inflammatory disease. Oxidative stress induced by generation of excess reactive oxygen species has emerged as a critical, final common mechanism in atherosclerosis. Reactive oxygen species (ROS) are a group of small reactive molecules that play critical roles in the regulation of various cell functions and biological processes. Although essential for vascular homeostasis, uncontrolled production of ROS is implicated in vascular injury. Endogenous anti-oxidants function as checkpoints to avoid these untoward consequences of ROS, and an imbalance in the oxidant/anti-oxidant mechanisms leads to a state of oxidative stress. In this review, we discuss the role of ROS and anti-oxidant mechanisms in the development and progression of atherosclerosis, the role of oxidized low-density lipoprotein cholesterol, and highlight potential anti-oxidant therapeutic strategies relevant to atherosclerosis.

RECENT FINDINGS

There is growing evidence on how traditional risk factors translate into oxidative stress and contribute to atherosclerosis. Clinical trials evaluating anti-oxidant supplements had failed to improve atherosclerosis. Current studies focus on newer ROS scavengers that specifically target mitochondrial ROS, newer nanotechnology-based drug delivery systems, gene therapies, and anti-miRNAs. Synthetic LOX-1 modulators that inhibit the effects of Ox-LDL are currently in development. Research over the past few decades has led to identification of multiple ROS generating systems that could potentially be modulated in atherosclerosis. Therapeutic approaches currently being used for atheroslcerotic vascular disease such as aspirin, statins, and renin-angiotensin system inhibitors exert a pleiotropic antioxidative effects. There is ongoing research to identify novel therapeutic modalities to selectively target oxidative stress in atherosclerosis.

Endothelial NF-κB Blockade Abrogates ANCA-Induced GN

ANCA-associated vasculitis (AAV) is a highly inflammatory condition in which ANCA-activated neutrophils interact with the endothelium, resulting in necrotizing vasculitis. We tested the hypothesis that endothelial NF-κB mediates necrotizing crescentic GN (NCGN) and provides a specific treatment target. Reanalysis of kidneys from previously examined murine NCGN disease models revealed NF-κB activation in affected kidneys, mostly as a p50/p65 heterodimer, and increased renal expression of NF-κB-dependent tumor necrosis factor α (TNF-α). NF-κB activation positively correlated with crescent formation, and nuclear phospho-p65 staining showed NF-κB activation within CD31-expressing endothelial cells (ECs) in affected glomeruli. Therefore, we studied the effect of ANCA on NF-κB activation in neutrophil/EC cocultures in vitro ANCA did not activate NF-κB in primed human neutrophils, but ANCA-stimulated primed neutrophils activated NF-κB in ECs, at least in part via TNF-α release. This effect increased endothelial gene transcription and protein production of NF-κB-regulated interleukin-8. Moreover, upregulation of endothelial NF-κB promoted neutrophil adhesion to EC monolayers, an effect that was inhibited by a specific IKKβ inhibitor. In a murine NCGN model, prophylactic application of E-selectin-targeted immunoliposomes packed with p65 siRNA to downregulate endothelial NF-κB significantly reduced urine abnormalities, renal myeloid cell influx, and NCGN. Increased glomerular endothelial phospho-p65 staining in patients with AAV indicated that NF-κB is activated in human NCGN also. We suggest that ANCA-stimulated neutrophils activate endothelial NF-κB, which contributes to NCGN and provides a potential therapeutic target in AAV.

Nucleic Acid Delivery for Endothelial Dysfunction in Cardiovascular Diseases

Endothelial dysfunction has been implicated in the pathophysiology of multiple cardiovascular diseases and involves components of both innate and acquired immune mechanisms. Identifying signature patterns and targets associated with endothelial dysfunction can help in the development of novel nanotherapeutic platforms for treatment of vascular diseases. This review discusses nucleic acid-based regulation of endothelial function and the different nucleic acid-based nanotherapeutic approaches designed to target endothelial dysfunction in cardiovascular disorders.

CVD and Oxidative Stress

Nowadays, it is known that oxidative stress plays at least two roles within the cell, the generation of cellular damage and the involvement in several signaling pathways in its balanced normal state. So far, a substantial amount of time and effort has been expended in the search for a clear link between cardiovascular disease (CVD) and the effects of oxidative stress. Here, we present an overview of the different sources and types of reactive oxygen species in CVD, highlight the relationship between CVD and oxidative stress and discuss the most prominent molecules that play an important role in CVD pathophysiology. Details are given regarding common pharmacological treatments used for cardiovascular distress and how some of them are acting upon ROS-related pathways and molecules. Novel therapies, recently proposed ROS biomarkers, as well as future challenges in the field are addressed. It is apparent that the search for a better understanding of how ROS are contributing to the pathophysiology of CVD is far from over, and new approaches and more suitable biomarkers are needed for the latter to be accomplished.

Molecular engineering of high affinity single-chain antibody fragment for endothelial targeting of proteins and nanocarriers in rodents and humans

Endothelial cells (EC) represent an important target for pharmacologic intervention, given their central role in a wide variety of human pathophysiologic processes. Studies in lab animal species have established that conjugation of drugs and carriers with antibodies directed to surface targets like the Platelet Endothelial Cell Adhesion Molecule-1 (PECAM-1, a highly expressed endothelial transmembrane protein) help to achieve specific therapeutic interventions in ECs. To translate such "vascular immunotargeting" to clinical practice, it is necessary to replace antibodies by advanced ligands that are more amenable to use in humans. We report the molecular design of a single chain variable antibody fragment (scFv) that binds with high affinity to human PECAM-1 and cross-reacts with its counterpart in rats and other animal species, allowing parallel testing in vivo and in human endothelial cells in microfluidic model. Site-specific modification of the scFv allows conjugation of protein cargo and liposomes, enabling their endothelial targeting in these models. This study provides a template for molecular engineering of ligands, enabling studies of drug targeting in animal species and subsequent use in humans.

Vascular Accessibility of Endothelial Targeted Ferritin Nanoparticles

Targeting nanocarriers to the endothelium, using affinity ligands to cell adhesion molecules such as ICAM-1 and PECAM-1, holds promise to improve the pharmacotherapy of many disease conditions. This approach capitalizes on the observation that antibody-targeted carriers of 100 nm and above accumulate in the pulmonary vasculature more effectively than free antibodies. Targeting of prospective nanocarriers in the 10-50 nm range, however, has not been studied. To address this intriguing issue, we conjugated monoclonal antibodies (Ab) to ICAM-1 and PECAM-1 or their single chain antigen-binding fragments (scFv) to ferritin nanoparticles (FNPs, size 12 nm), thereby producing Ab/FNPs and scFv/FNPs. Targeted FNPs retained their typical symmetric core-shell structure with sizes of 20-25 nm and ∼4-5 Ab (or ∼7-9 scFv) per particle. Ab/FNPs and scFv/FNPs, but not control IgG/FNPs, bound specifically to cells expressing target molecules and accumulated in the lungs after intravenous injection, with pulmonary targeting an order of magnitude higher than free Ab. Most intriguing, the targeting of Ab/FNPs to ICAM-1, but not PECAM-1, surpassed that of larger Ab/carriers targeted by the same ligand. These results indicate that (i) FNPs may provide a platform for targeting endothelial adhesion molecules with carriers in the 20 nm size range, which has not been previously reported; and (ii) ICAM-1 and PECAM-1 (known to localize in different domains of endothelial plasmalemma) differ in their accessibility to circulating objects of this size, common for blood components and nanocarriers.

Recent Advances in Targeted, Self-Assembling Nanoparticles to Address Vascular Damage Due to Atherosclerosis

Self-assembling nanoparticles functionalized with targeting moieties have significant potential for atherosclerosis nanomedicine. While self-assembly allows the easy construction (and degradation) of nanoparticles with therapeutic or diagnostic functionality, or both, the targeting agent can direct them to a specific molecular marker within a given stage of the disease. Therefore, supramolecular nanoparticles have been investigated in the last decade as molecular imaging agents or explored as nanocarriers that can decrease the systemic toxicity of drugs by producing accumulation predominantly in specific tissues of interest. In this Progress Report, the pathogenesis of atherosclerosis and the damage caused to vascular tissue are described, as well as the current diagnostic and treatment options. An overview of targeted strategies using self-assembling nanoparticles is provided, including liposomes, high density lipoproteins, protein cages, micelles, proticles, and perfluorocarbon nanoparticles. Finally, an overview is given of current challenges, limitations, and future applications for personalized medicine in the context of atherosclerosis of self-assembling nanoparticles.

Targeting Rapamycin to Podocytes Using a Vascular Cell Adhesion Molecule-1 (VCAM-1)-Harnessed SAINT-Based Lipid Carrier System

Together with mesangial cells, glomerular endothelial cells and the basement membrane, podocytes constitute the glomerular filtration barrier (GFB) of the kidney. Podocytes play a pivotal role in the progression of various kidney-related diseases such as glomerular sclerosis and glomerulonephritis that finally lead to chronic end-stage renal disease. During podocytopathies, the slit-diaphragm connecting the adjacent podocytes are detached leading to severe loss of proteins in the urine. The pathophysiology of podocytopathies makes podocytes a potential and challenging target for nanomedicine development, though there is a lack of known molecular targets for cell selective drug delivery. To identify VCAM-1 as a cell-surface receptor that is suitable for binding and internalization of nanomedicine carrier systems by podocytes, we investigated its expression in the immortalized podocyte cell lines AB8/13 and MPC-5, and in primary podocytes. Gene and protein expression analyses revealed that VCAM-1 expression is increased by podocytes upon TNFα-activation for up to 24 h. This was paralleled by anti-VCAM-1 antibody binding to the TNFα-activated cells, which can be employed as a ligand to facilitate the uptake of nanocarriers under inflammatory conditions. Hence, we next explored the possibilities of using VCAM-1 as a cell-surface receptor to deliver the potent immunosuppressant rapamycin to TNFα-activated podocytes using the lipid-based nanocarrier system Saint-O-Somes. Anti-VCAM-1-rapamycin-SAINT-O-Somes more effectively inhibited the cell migration of AB8/13 cells than free rapamycin and non-targeted rapamycin-SAINT-O-Somes indicating the potential of VCAM-1 targeted drug delivery to podocytes.

Understanding and exploiting nanoparticles' intimacy with the blood vessel and blood

While the blood vessel is seldom the target tissue, almost all nanomedicine will interact with blood vessels and blood at some point of time along its life cycle in the human body regardless of their intended destination. Despite its importance, many bionanotechnologists do not feature endothelial cells (ECs), the blood vessel cells, or consider blood effects in their studies. Including blood vessel cells in the study can greatly increase our understanding of the behavior of any given nanomedicine at the tissue of interest or to understand side effects that may occur in vivo. In this review, we will first describe the diversity of EC types found in the human body and their unique behaviors and possibly how these important differences can implicate nanomedicine behavior. Subsequently, we will discuss about the protein corona derived from blood with foci on the physiochemical aspects of nanoparticles (NPs) that dictate the protein corona characteristics. We would also discuss about how NPs characteristics can affect uptake by the endothelium. Subsequently, mechanisms of how NPs could cross the endothelium to access the tissue of interest. Throughout the paper, we will share some novel nanomedicine related ideas and insights that were derived from the understanding of the NPs' interaction with the ECs. This review will inspire more exciting nanotechnologies that had accounted for the complexities of the real human body.

Small-nucleic-acid-based therapeutic strategy targeting the transcription factors regulating the vascular inflammation, remodeling and fibrosis in atherosclerosis

Atherosclerosis arises when injury to the arterial wall induces an inflammatory cascade that is sustained by a complex network of cytokines, together with accumulation of lipids and fibrous material. Inflammatory cascades involve leukocyte adherence and chemotaxis, which are coordinated by the local secretion of adhesion molecules, chemotactic factors, and cytokines. Transcription factors are critical to the integration of the various steps of the cascade response to mediators of vascular injury, and are induced in a stimulus-dependent and cell-type-specific manner. Several small-nucleic-acid-based therapeutic strategies have recently been developed to target transcription factors: antisense oligodeoxynucleotides, RNA interference, microRNA, and decoy oligodeoxynucleotides. The aim of this review was to provide an overview of these particular targeted therapeutic strategies, toward regulation of the vascular inflammation, remodeling and fibrosis associated with atherosclerosis.

SAINT-liposome-polycation particles, a new carrier for improved delivery of siRNAs to inflamed endothelial cells

Interference with acute and chronic inflammatory processes by means of delivery of siRNAs into microvascular endothelial cells at a site of inflammation demands specific, non-toxic and effective siRNA delivery system. In the current work we describe the design and characterization of siRNA carriers based on cationic pyridinium-derived lipid 1-methyl-4-(cis-9-dioleyl)methyl-pyridinium-chloride) (SAINT-C18) and the transfection enhancer protamine, complexed with siRNA/carrier DNA or siRNA only. These carriers, called SAINT-liposome-polycation-DNA (S-LPD) and SAINT-liposome-polycation (S-LP), have a high efficiency of siRNA encapsulation, low cellular toxicity, and superior efficacy of gene downregulation in endothelial cells in vitro as compared to DOTAP-LPD. Incorporation of 10 mol% PEG and anti-E-selectin antibody in these formulations resulted in selective siRNA delivery into activated endothelial cells. Furthermore, we showed that the physicochemical characteristics of S-LPD and S-LP, including size-stability and maintenance of the siRNA integrity in the presence of serum at 37 °C, comply with requirements for in vivo application.

Synthesis and structure-activity relationships of 4-fluorophenyl-imidazole p38α MAPK, CK1δ and JAK2 kinase inhibitors

The synthesis and structure-activity relationships of novel 4-(4'-fluorophenyl)imidazoles as selective p38α MAPK, CK1δ and JAK2 inhibitors with improved water solubility are described. Microwave-assisted multicomponent reactions afforded 4-fluorophenyl-2,5-disubstituted imidazoles. Carboxylate and phosphonate groups were introduced via 'click' reactions. The kinase selectivity was influenced by the heteroaryl group at imidazole C-5 and the position of a carboxylic acid or tetrazole at imidazole C-2. For example, pyrimidines 15 and 34 inhibited p38α MAPK with IC50=250 nM and 96 nM, respectively. Pyridine 3 gave CK1δ inhibition with IC50=89 nM and pyridin-2-one 31 gave JAK2 inhibition with IC50=62 nM.

Nanomedicine-based strategies for treatment of atherosclerosis

Atherosclerosis is a chronic inflammatory disease of the arterial wall that arises from an imbalanced lipid metabolism and a maladaptive inflammatory response. Despite intensive research on mechanisms underlying atherosclerotic lesion formation and progression during the past decade, translation of this knowledge into the clinic is scarce. Although developments have primarily been made in the area of antitumor therapy, recent advances have shown the potential of nanomedicine-based treatment strategies for atherosclerosis. Here we describe the features of currently available nanomedical formulations that have been optimized for atherosclerosis treatment, and we further describe how they can be instructed to target inflammatory processes in the arterial wall. Despite their limitations, nanomedical applications might hold promise for personalized medicine, and further efforts are needed to improve atherosclerosis-specific targeting.

Endothelial targeting of nanocarriers loaded with antioxidant enzymes for protection against vascular oxidative stress and inflammation

Endothelial-targeted delivery of antioxidant enzymes, catalase and superoxide dismutase (SOD), is a promising strategy for protecting organs and tissues from inflammation and oxidative stress. Here we describe Protective Antioxidant Carriers for Endothelial Targeting (PACkET), the first carriers capable of targeted endothelial delivery of both catalase and SOD. PACkET formed through controlled precipitation loaded ~30% enzyme and protected it from proteolytic degradation, whereas attachment of PECAM monoclonal antibodies to surface of the enzyme-loaded carriers, achieved without adversely affecting their stability and functionality, provided targeting. Isotope tracing and microscopy showed that PACkET exhibited specific endothelial binding and internalization in vitro. Endothelial targeting of PACkET was validated in vivo by specific (vs IgG-control) accumulation in the pulmonary vasculature after intravenous injection achieving 33% of injected dose at 30 min. Catalase loaded PACkET protects endothelial cells from killing by H2O2 and alleviated the pulmonary edema and leukocyte infiltration in mouse model of endotoxin-induced lung injury, whereas SOD-loaded PACkET mitigated cytokine-induced endothelial pro-inflammatory activation and endotoxin-induced lung inflammation. These studies indicate that PACkET offers a modular approach for vascular targeting of therapeutic enzymes.

Anti-VCAM-1 SAINT-O-Somes enable endothelial-specific delivery of siRNA and downregulation of inflammatory genes in activated endothelium in vivo

The pivotal role of endothelial cells in the pathology of inflammatory diseases raised interest in the development of short interfering RNA (siRNA) delivery devices for selective pharmacological intervention in the inflamed endothelium. The current study demonstrates endothelial specific delivery of siRNAs and downregulation of inflammatory genes in activated endothelium in vivo by applying a novel type of targeted liposomes based on the cationic amphiphile SAINT-C18 (1-methyl-4-(cis-9-dioleyl)methyl-pyridinium-chloride). To create specificity for inflamed endothelial cells, these so-called SAINT-O-Somes were harnessed with antibodies against vascular cell adhesion protein 1 (VCAM-1). In TNFα challenged mice, intravenously administered anti-VCAM-1 SAINT-O-Somes exerted long circulation times and homed to VCAM-1 expressing endothelial cells in inflamed organs. The formulations were devoid of liver and kidney toxicity. Using anti-VCAM-1 SAINT-O-Somes we successfully delivered siRNA to knock down VE-cadherin mRNA in inflamed renal microvasculature, as demonstrated by using laser microdissection of different microvascular beds prior to analysis of gene expression. Using the same strategy, we demonstrated local attenuation of endothelial inflammatory response towards lipopolysaccharide in kidneys of mice treated with anti-VCAM-1 SAINT-O-Somes containing NFκB p65 specific siRNA. This study is the first demonstration of a novel, endothelial specific carrier that is suitable for selective in vivo delivery of siRNAs into inflamed microvascular segments and interference with disease associated endothelial activation.

Effective siRNA delivery to inflamed primary vascular endothelial cells by anti-E-selectin and anti-VCAM-1 PEGylated SAINT-based lipoplexes

The endothelium represents an attractive therapeutic target due to its pivotal role in many diseases including chronic inflammation and cancer. Small interfering RNAs (siRNAs) specifically interfere with the expression of target genes and are considered an important new class of therapeutics. However, due to their size and charge, siRNAs do not spontaneously enter unperturbed endothelial cells (EC). To overcome this problem, we developed novel lipoplexes for siRNA delivery that are based on the cationic amphiphilic lipid SAINT-C18. Antibodies recognizing disease induced cell adhesion molecules were employed to create cell specificity resulting in so-called antibody-SAINTargs. To improve particle stability, antibody-SAINTargs were further optimized for EC-specific siRNA-mediated gene silencing by addition of polyethylene glycol (PEG). Although PEGylated antibody-SAINTargs maintained specificity, they lost their siRNA delivery capacity. Coupling of antibodies to the distal end of PEG (so-called antibody-SAINTPEGargs), resulted in anti-E-selectin- and anti-vascular cell adhesion molecule (VCAM)-1-SAINTPEGarg that preserved their antigen recognition and their capability to specifically deliver siRNA into inflammation-activated primary endothelial cells. The enhanced uptake of siRNA by antibody-SAINTPEGargs was followed by improved silencing of the target gene VE-cadherin, demonstrating that antibody-SAINTPEGargs were capable of functionally delivering siRNA into primary endothelial cells originating from different vascular beds. In conclusion, the newly developed, physicochemically stable, and EC-specific siRNA carrying antibody-SAINTPEGargs selectively down-regulate target genes in primary endothelial cells that are generally difficult to transfect.