Targeting and therapeutic peptides in nanomedicine for atherosclerosis

Photodynamic Therapy for Atherosclerosis

Atherosclerosis, which currently contributes to 31% of deaths globally, is of critical cardiovascular concern. Current diagnostic tools and biomarkers are limited, emphasizing the need for early detection. Lifestyle modifications and medications form the basis of treatment, and emerging therapies such as photodynamic therapy are being developed. Photodynamic therapy involves a photosensitizer selectively targeting components of atherosclerotic plaques. When activated by specific light wavelengths, it induces localized oxidative stress aiming to stabilize plaques and reduce inflammation. The key advantage lies in its selective targeting, sparing healthy tissues. While preclinical studies are encouraging, ongoing research and clinical trials are crucial for optimizing protocols and ensuring long-term safety and efficacy. The potential combination with other therapies makes photodynamic therapy a versatile and promising avenue for addressing atherosclerosis and associated cardiovascular disease. The investigations underscore the possibility of utilizing photodynamic therapy as a valuable treatment choice for atherosclerosis. As advancements in research continue, photodynamic therapy might become more seamlessly incorporated into clinical approaches for managing atherosclerosis, providing a blend of efficacy and limited invasiveness.

Atherosclerosis treatment with nanoagent: potential targets, stimulus signals and drug delivery mechanisms

Cardiovascular disease (CVDs) is the first killer of human health, and it caused up at least 31% of global deaths. Atherosclerosis is one of the main reasons caused CVDs. Oral drug therapy with statins and other lipid-regulating drugs is the conventional treatment strategies for atherosclerosis. However, conventional therapeutic strategies are constrained by low drug utilization and non-target organ injury problems. Micro-nano materials, including particles, liposomes, micelles and bubbles, have been developed as the revolutionized tools for CVDs detection and drug delivery, specifically atherosclerotic targeting treatment. Furthermore, the micro-nano materials also could be designed to intelligently and responsive targeting drug delivering, and then become a promising tool to achieve atherosclerosis precision treatment. This work reviewed the advances in atherosclerosis nanotherapy, including the materials carriers, target sites, responsive model and treatment results. These nanoagents precisely delivery the therapeutic agents to the target atherosclerosis sites, and intelligent and precise release of drugs, which could minimize the potential adverse effects and be more effective in atherosclerosis lesion.

Surface-modified nanotherapeutics targeting atherosclerosis

Atherosclerosis is a chronic and metabolic-related disease that is a serious threat to human health. Currently available diagnostic and therapeutic measures for atherosclerosis lack adequate efficiency which requires promising alternative approaches. Nanotechnology-based nano-delivery systems allow for new perspectives for atherosclerosis therapy. Surface-modified nanoparticles could achieve highly effective therapeutic effects by binding to specific receptors that are abnormally overexpressed in atherosclerosis, with less adverse effects on non-target tissues. The main purpose of this review is to summarize the research progress and design ideas to target atherosclerosis using a variety of ligand-modified nanoparticle systems, discuss the shortcomings of current vector design, and look at future development directions. We hope that this review will provide novel research strategies for the design and development of nanotherapeutics targeting atherosclerosis.

Therapeutic Response of miR-145 Micelles on Patient-Derived Vascular Smooth Muscle Cells

During atherosclerosis, vascular smooth muscle cells (VSMCs) undergo a phenotypic transition from a healthy contractile state into pathological phenotypes including a proliferative and migratory, synthetic phenotype and osteochondrogenic-like phenotype that exacerbate plaques. Thus, inhibiting the transition of healthy, quiescent VSMCs to atherogenic cell types has the potential to mitigate atherosclerosis. To that end, previously, we reported that delivery of microRNA-145 (miR-145, a potent gatekeeper of the contractile VSMC phenotype) using nanoparticle micelles limited atherosclerotic plaque growth in murine models of atherosclerosis. Building on this preclinical data and toward clinical application, in this study, we tested the therapeutic viability of miR-145 micelles on patient-derived VSMCs and evaluated their effects based on disease severity. We collected vascular tissues from 11 patients with healthy, moderate, or severe stages of atherosclerosis that were discarded following vascular surgery or organ transplant, and isolated VSMCs from these tissues. We found that with increasing disease severity, patient-derived VSMCs had decreasing levels of contractile markers (miR-145, ACTA2, MYH11) and increasing levels of synthetic markers (KLF4, KLF5, and ELK1). Treatment with miR-145 micelles showed that an increase in disease severity correlated with a more robust response to therapy in VSMCs. Notably, miR-145 micelle therapy rescued contractile marker expression to baseline contractile levels in VSMCs derived from the most severely diseased tissues. As such, we demonstrate the use of miR-145 micelles across different stages of atherosclerosis disease and present further evidence of the translatability of miR-145 micelle treatment for atherosclerosis.

Computational Evolution Protocol for Peptide Design

Computational peptide design is useful for therapeutics, diagnostics, and vaccine development. To select the most promising peptide candidates, the key is describing accurately the peptide-target interactions at the molecular level. We here review a computational peptide design protocol whose key feature is the use of all-atom explicit solvent molecular dynamics for describing the different peptide-target complexes explored during the optimization. We describe the milestones behind the development of this protocol, which is now implemented in an open-source code called PARCE. We provide a basic tutorial to run the code for an antibody fragment design example. Finally, we describe three additional applications of the method to design peptides for different targets, illustrating the broad scope of the proposed approach.

Theranostic nanoplatform to target macrophages enables the inhibition of atherosclerosis progression and fluorescence imaging of plaque in ApoE(-/-) mice

Background

Rupture of atherosclerotic plaque can cause acute malignant heart and cerebrovascular events, such as acute coronary heart disease, stroke and so on, which seriously threaten the safety of human life and property. Therefore, the early diagnosis and inhibition of atherosclerotic plaque progress still be a vital task.

Results

In this study, we presented the development of composite mesoporous silica nanoparticle (Ru(bpy)₃@SiO₂-mSiO₂, CMSN)-based nanomedicines (NMs) (Ru(bpy)₃@SiO₂-mSiO₂@SRT1720@AntiCD36, CMSN@SRT@Anti) for accurate diagnosis and treatment of atherosclerosis (AS). In vitro cell experiments showed that both RAW264.7 and oxidized low density lipoprotein (ox-LDL)-stimulated RAW264.7 cells could significantly uptake CMSN@SRT@Anti. Conversely, little fluorescence signal could be observed in CMSN@SRT group, showing the excellent targeting ability of CMSN@SRT@Anti to Class II scavenger receptor, CD36 on macrophage. Additionally, such fluorescence signal was significantly stronger in ox-LDL-stimulated RAW264.7 cells, which might benefit from the upregulated expression of CD36 on macrophages after ox-LDL treatment. For another, compared with free SRT1720, CMSN@SRT@Anti had a better and more significant effect on the inhibition of macrophage foaming process, which indicated that drug-carrying mesoporous silicon with targeting ability could enhance the efficacy of SRT1720. Animal experimental results showed that after the abdominal injection of CMSN@SRT@Anti, the aortic lesions of ApoE-/-mice could be observed with obvious and persistent fluorescence signals. After 4 weeks post-treatment, the serum total cholesterol, aortic plaque status and area were significantly improved in the mouse, and the effect was better than that in the free SRT1720 group or the CMSN@SRT group.

Conclusions

The designed CMSN@SRT@Anti with excellent biocompatibility, high-performance and superior atherosclerosis-targeting ability has great potential for accurate identification and targeted therapy of atherosclerotic diseases.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-00962-w.

Exosomes in Atherosclerosis, a Double-Edged Sword: Their Role in Disease Pathogenesis and Their Potential as Novel Therapeutics

Cardiovascular disease (CAD) due to atherosclerosis is a major cause of death worldwide. The development of atherosclerosis involves intercellular communication facilitated by exosomes secreted from vascular endothelial cells (VECs), vascular smooth muscle cells (VSMCs), immune cells, and platelets. In this review, we summarize the current understanding of exosome biogenesis and uptake, and discuss atherogenic and atheroprotective functions of exosomes secreted from these cell types. In addition, we examine the potential of enhancing the therapeutic and targeting ability of exosomes exhibiting atheroprotective function by drug loading and surface modification with targeting ligands. We conclude with current challenges associated with exosome engineering for therapeutic use.

Transdermal Delivery of Kidney-Targeting Nanoparticles Using Dissolvable Microneedles

INTRODUCTION

Chronic kidney disease (CKD) affects approximately 13% of the world's population and will lead to dialysis or kidney transplantation. Unfortunately, clinically available drugs for CKD show limited efficacy and toxic extrarenal side effects. Hence, there is a need to develop targeted delivery systems with enhanced kidney specificity that can also be combined with a patient-compliant administration route for such patients that need extended treatment. Towards this goal, kidney-targeted nanoparticles administered through transdermal microneedles (KNP/MN) is explored in this study.

METHODS

A KNP/MN patch was developed by incorporating folate-conjugated micelle nanoparticles into polyvinyl alcohol MN patches. Rhodamine B (RhB) was encapsulated into KNP as a model drug and evaluated for biocompatibility and binding with human renal epithelial cells. For MN, skin penetration efficiency was assessed using a Parafilm model, and penetration was imaged via scanning electron microscopy. In vivo, KNP/MN patches were applied on the backs of C57BL/6 wild type mice and biodistribution, organ morphology, and kidney function assessed.

RESULTS

KNP showed high biocompatibility and folate-dependent binding in vitro, validating KNP's targeting to folate receptors in vitro. Upon transdermal administration in vivo, KNP/MN patches dissolved within 30 min. At varying time points up to 48 h post-KNP/MN administration, higher accumulation of KNP was found in kidneys compared with MN that consisted of the non-targeting, control-NP. Histological evaluation demonstrated no signs of tissue damage, and kidney function markers, serum blood urea nitrogen and urine creatinine, were found to be within normal ranges, indicating preservation of kidney health.

CONCLUSIONS

Our studies show potential of KNP/MN patches as a non-invasive, self-administrable platform to direct therapies to the kidneys.

Glycoprotein VI (GPVI)-functionalized nanoparticles targeting arterial injury sites under physiological flow

Thrombus formation at athero-thrombotic sites is initiated by the exposure of collagen followed by platelet adhesion mediated by the platelet-specific collagen receptor glycoprotein VI (GPVI). Here, dimeric GPVI was used as a targeting motif to functionalize polymeric nanoparticle-based drug carriers and to show that with proper design, such GPVI-coated nanoparticles (GPNs) can efficiently and specifically target arterial injury sites while withstanding physiological flow. In a microfluidic model, under physiological shear levels (1-40 dyne/cm²), 200 nm and 2 μm GPNs exhibited a >60 and >10-fold increase in binding to collagen compared to control particles, respectively. In vitro experiments in an arterial stenosis injury model, subjected to physiological pulsatile flow, showed shear-enhanced adhesion of 200 nm GPNs at the stenosis region which was confirmed in vivo in a mice ligation carotid injury model using intravital microscopy. Altogether, our results illustrate how engineering tools can be harnessed to design nano-carriers that efficiently target cardiovascular disease sites.

Construction of dual nanomedicines for the imaging and alleviation of atherosclerosis

Magnetic resonance imaging (MRI) is an essential tool for the diagnosis of atherosclerosis, a chronic cardiovascular disease. MRI primarily uses superparamagnetic iron oxide (SPIO) as a contrast agent. However, SPIO integrated with therapeutic drugs has rarely been studied. In this study, we explored biocompatible paramagnetic iron-oxide nanoparticles (NPs) in a complex with low pH-sensitive cyclodextrin for the diagnostic imaging and treatment of atherosclerosis. The NPs were conjugated with profilin-1 antibody (PFN1) to specifically target vascular smooth muscle cells (VSMCs) in the atherosclerotic plaque and integrated with the anti-inflammatory drug, rapamycin. The PFN1-CD-MNPs were easily binded to the VSMCs, indicating their good biocompatibility and low renal toxicity over the long term. Ex vivo near-infrared fluorescence (NIRF) imaging and in vivo MRI indicated the accumulation of PFN1-CD-MNPs in the atherosclerotic plaque. The RAP@PFN1-CD-MNPs alleviated the progression of arteriosclerosis. Thus, PFN1-CD-MNPs served not only as multifunctional imaging probes but also as nanovehicles for the treatment of atherosclerosis.

Peptide-based targeting of immunosuppressive cells in cancer

Cancer progression is marked by the infiltration of immunosuppressive cells, such as tumor-associated macrophages (TAMs), regulatory T lymphocytes (Tregs), and myeloid-derived suppressor cells (MDSCs). These cells play a key role in abrogating the cytotoxic T lymphocyte-mediated (CTL) immune response, allowing tumor growth to proceed unabated. Furthermore, targeting these immunosuppressive cells through the use of peptides and peptide-based nanomedicine has shown promising results. Here we review the origins and functions of immunosuppressive cells in cancer progression, peptide-based systems used in their targeting, and explore future avenues of research regarding cancer immunotherapy. The success of these studies demonstrates the importance of the tumor immune microenvironment in the propagation of cancer and the potential of peptide-based nanomaterials as immunomodulatory agents.

Integrin αvβ3 Receptor Overexpressing on Tumor-Targeted Positive MRI-Guided Chemotherapy

Multifunctional nanomaterials with targeted imaging and chemotherapy have high demand with great challenge. Herein, we rationally aimed to design multifunctional drug delivery systems by RGD-modified chitosan (CH)-coated nanoneedles (NDs) of gadolinium arsenate (RGD-CH-Gd-AsNDs). These NDs have multifunctionality for imaging and targeted therapy. NDs on intravenous administration demonstrated significant accumulation of As ions/species in tumor tissues, which was monitored by the change in T₁-weighted magnetic resonance (MR) imaging. Moreover, NDs were well opsonized in cells with high specificity, subsequently inducing apoptosis to the HepG2 cells. Consequent to this, the in vivo results demonstrated biosafety, enhanced tumor targeting, and tumor regression in a subcutaneously transplanted xenograft model in nude mice. These RGD-CH-Gd-AsNDs have great potential, and we anticipate that they could serve as a novel platform for real-time T₁-weighted MR diagnosis and chemotherapy.

Nanotechnological Strategies as Smart ways for Diagnosis and Treatment of the Atherosclerosis

Atherosclerosis provokes a continuous worsening of affected vessels causing a blood flow diminution with several complications and with clinical manifestations that generally appear in advanced phases of the illness. Hence, the conventional therapies are not enough because the atherosclerotic injuries are often irrevocable. For this reason, emerges the necessity to implement smart ways of drug supply and develop new therapeutic targets that decrease the advance atherosclerotic lesion. It results due to particular interest to use new tools for prevention, diagnosis, and treatment of this cardiovascular disease, thus concentrating our attention to accomplish better management on the immune system. Finally, this mini-review highlights the most recent knowledge about nanotechnology as a robust, novel and promissory therapeutic option applied to atherosclerotic pathology, nevertheless, we also alert for possible issues associated with their use.

Atherosclerosis Treatment with Stimuli-Responsive Nanoagents: Recent Advances and Future Perspectives

Atherosclerosis is the root of approximately one-third of global mortalities. Nanotechnology exhibits splendid prospects to combat atherosclerosis at the molecular level by engineering smart nanoagents with versatile functionalizations. Significant advances in nanoengineering enable nanoagents to autonomously navigate in the bloodstream, escape from biological barriers, and assemble with their nanocohort at the targeted lesion. The assembly of nanoagents with endogenous and exogenous stimuli breaks down their shells, facilitates intracellular delivery, releases their cargo to kill the corrupt cells, and gives imaging reports. All these improvements pave the way toward personalized medicine for atherosclerosis. This review systematically summarizes the recent advances in stimuli-responsive nanoagents for atherosclerosis management and its progress in clinical trials.

Cellular Vehicles Based on Neutrophils Enable Targeting of Atherosclerosis

Given the multiple interactions between neutrophils (NEs) and atherosclerosis (AS), in this study, we exploited NEs as cellular vehicles loaded with cationic liposomes for actively targeting atherosclerotic sites. The cellular vehicles based on NEs possess efficient internalization of cationic liposomes and sensitive response to the chemotaxis of atherosclerotic inflammatory cells, which ultimately realize the targeted delivery of the cargos into the target cells in vitro. Moreover, these effects also translated to significant enhancement of the accumulation of NEs' cargos into the atherosclerotic plaque in vivo after administering NE vehicles to the AS animal model. Consequently, cellular vehicles based on NEs could be a novel strategy for targeted delivery of payloads into atherosclerotic plaque, which would facilitate theranostics for AS and the development of anti-AS drugs to manage the disease.

Promoting the Delivery of Nanoparticles to Atherosclerotic Plaques by DNA Coating

Many nanoparticle-based carriers to atherosclerotic plaques contain peptides, lipoproteins, and sugars, yet the application of DNA-based nanostructures for targeting plaques remains infrequent. In this work, we demonstrate that DNA-coated superparamagnetic iron oxide nanoparticles (DNA-SPIONs), prepared by attaching DNA oligonucleotides to poly(ethylene glycol)-coated SPIONs (PEG-SPIONs), effectively accumulate in the macrophages of atherosclerotic plaques following an intravenous injection into apolipoprotein E knockout (ApoE^-/-) mice. DNA-SPIONs enter RAW 264.7 macrophages faster and more abundantly than PEG-SPIONs. DNA-SPIONs mostly enter RAW 264.7 cells by engaging Class A scavenger receptors (SR-A) and lipid rafts and traffic inside the cell along the endolysosomal pathway. ABS-SPIONs, nanoparticles with a similarly polyanionic surface charge as DNA-SPIONs but bearing abasic oligonucleotides also effectively bind to SR-A and enter RAW 264.7 cells. Near-infrared fluorescence imaging reveals evident localization of DNA-SPIONs in the heart and aorta 30 min post-injection. Aortic iron content for DNA-SPIONs climbs to the peak (∼60% ID/g) 2 h post-injection (accompanied by profuse accumulation in the aortic root), but it takes 8 h for PEG-SPIONs to reach the peak aortic amount (∼44% ID/g). ABS-SPIONs do not appreciably accumulate in the aorta or aortic root, suggesting that the DNA coating (not the surface charge) dictates in vivo plaque accumulation. Flow cytometry analysis reveals more pronounced uptake of DNA-SPIONs by hepatic endothelial cells, splenic macrophages and dendritic cells, and aortic M2 macrophages (the cell type with the highest uptake in the aorta) than PEG-SPIONs. In summary, coating nanoparticles with DNA is an effective strategy of promoting their systemic delivery to atherosclerotic plaques.

Artificial intelligence in nanomedicine

The field of nanomedicine has made substantial strides in the areas of therapeutic and diagnostic development. For example, nanoparticle-modified drug compounds and imaging agents have resulted in markedly enhanced treatment outcomes and contrast efficiency. In recent years, investigational nanomedicine platforms have also been taken into the clinic, with regulatory approval for Abraxane® and other products being awarded. As the nanomedicine field has continued to evolve, multifunctional approaches have been explored to simultaneously integrate therapeutic and diagnostic agents onto a single particle, or deliver multiple nanomedicine-functionalized therapies in unison. Similar to the objectives of conventional combination therapy, these strategies may further improve treatment outcomes through targeted, multi-agent delivery that preserves drug synergy. Also, similar to conventional/unmodified combination therapy, nanomedicine-based drug delivery is often explored at fixed doses. A persistent challenge in all forms of drug administration is that drug synergy is time-dependent, dose-dependent and patient-specific at any given point of treatment. To overcome this challenge, the evolution towards nanomedicine-mediated co-delivery of multiple therapies has made the potential of interfacing artificial intelligence (AI) with nanomedicine to sustain optimization in combinatorial nanotherapy a reality. Specifically, optimizing drug and dose parameters in combinatorial nanomedicine administration is a specific area where AI can actionably realize the full potential of nanomedicine. To this end, this review will examine the role that AI can have in substantially improving nanomedicine-based treatment outcomes, particularly in the context of combination nanotherapy for both N-of-1 and population-optimized treatment.

Shape Effects of Peptide Amphiphile Micelles for Targeting Monocytes

Peptide amphiphile micelles (PAMs) are a nanoparticle platform that have gained popularity for their targeting versatility in a wide range of disease models. An important aspect of micelle design is considering the type of hydrophobic moiety used to synthesize the PAM, which can act as a contributing factor regarding their morphology and targeting capabilities. To delineate and compare the characteristics of spherical and cylindrical micelles, we incorporated the monocyte-targeting chemokine, monocyte chemoattractant protein-1 (MCP-1), into our micelles (MCP-1 PAMs). We report that both shapes of nanoparticles were biocompatible with monocytes and enhanced the secondary structure of the MCP-1 peptide, thereby improving the ability of the micelles to mimic the native MCP-1 protein structure. As a result, both shapes of MCP-1 PAMs effectively targeted monocytes in an in vitro binding assay with murine monocytes. Interestingly, cylindrical PAMs showed a greater ability to attract monocytes compared to spherical PAMs in a chemotaxis assay. However, the surface area, the multivalent display of peptides, and the zeta potential of PAMs may also influence their biomimetic properties. Herein, we introduce variations in the methods of PAM synthesis and discuss the differences in PAM characteristics that can impact the recruitment of monocytes, a process associated with disease and cancer progression.

Theranostic Nanoparticles for Tracking and Monitoring Disease State

The development of novel nanoparticles consisting of both diagnostic and therapeutic components has increased over the past decade. These "theranostic" nanoparticles have been tailored toward one or more types of imaging modalities and have been developed for optical imaging, magnetic resonance imaging, ultrasound, computed tomography, and nuclear imaging comprising both single-photon computed tomography and positron emission tomography. In this review, we focus on state-of-the-art theranostic nanoparticles that are capable of both delivering therapy and self-reporting/tracking disease through imaging. We discuss challenges and the opportunity to rapidly adjust treatment for individualized medicine.

The CD44-HA axis and inflammation in atherosclerosis: A temporal perspective

Cardiovascular disease (CVD) due to atherosclerosis is a disease of chronic inflammation at both the systemic and the tissue level. CD44 has previously been implicated in atherosclerosis in both humans and mice. This multi-faceted receptor plays a critical part in the inflammatory response during the onset of CVD, though little is known of CD44's role during the latter stages of the disease. This review focuses on the role of CD44-dependent HA-dependent effects on inflammatory cells in several key processes, from disease initiation throughout the progression of atherosclerosis. Understanding how CD44 and HA regulate inflammation in atherogenesis is key in determining the utility of the CD44-HA axis as a therapeutic target to halt disease and potentially promote disease regression.

Peptide and antibody ligands for renal targeting: nanomedicine strategies for kidney disease

The kidney is one of the body's main filtration organs, and hence, opportunity exists for designing nanomedicine that can naturally accumulate in the kidneys for renal diseases. In addition to traditional physiochemical properties for kidney accumulation, such as size and charge, synthesized nanoparticles can be conjugated with targeting ligands which further home the nanocarriers to cell types of interest. In this review, we highlight key studies that have shown success in utilizing peptide- or antibody-based ligands in nanoparticles to target the glomerulus, podocytes, or renal tubule cells in the kidney. In addition, other ligand candidates which have shown renal affinity, but have not yet been integrated into a nanoparticle are also presented. These studies can provide insight into the design of novel clinical solutions for improved detection, prevention, and treatment of renal diseases using nanomedicine efforts.

Comparison of in vivo targeting ability between cRGD and collagen-targeting peptide conjugated nano-carriers for atherosclerosis

Atherosclerosis plaque is a major cause of cardiovascular diseases across the globe and a silent killer. There are no physical symptoms of the disease in its early stage and current diagnostic techniques cannot detect the small plaques effectively or safely. Plaques formed in blood vessels can cause serious clinical problems such as impaired blood flow or sudden death, regardless of their size. Thus, detecting early stage of plaques is especially more important to effectively reduce the risk of atherosclerosis. Nanoparticle based delivery systems are recognized as a promising option to fight against this disease, and various targeting ligands are typically used to improve their efficiency. So, the choice of appropriate targeting ligand is a crucial factor for optimal targeting efficiency. cRGD peptide and collagen IV targeting peptide, which binds with the α_vβ₃ integrin overexpressed in the neovasculature of the plaque and collagen type IV present in the plaque, respectively, are frequently used for the targeting of nanoparticles. However, at present no study has directly compared these two peptides. Therefore, in this study, we have prepared cRGD or collagen IV targeting (Col IV-tg-) peptide conjugated and iron oxide nanoparticle (IONP) loaded Pluronic based nano-carriers for systemic comparison of their targeting ability towards in vivo atherosclerotic plaque in Apolipoprotein E deficient (Apo E^-/-) mouse model. Nano-carriers with similar size, surface charge, and IONP loading content but with different targeting ligands were analyzed through in vitro and in vivo experiments. Near infrared fluorescence imaging and magnetic resonance imaging techniques as well as Prussian blue staining were used to compare the accumulation of different ligand conjugated nano-caariers in the aorta of atherosclerotic mice. Our results indicate that cRGD based targeting is more efficient than Col IV-tg-peptide in the early stage of atherosclerosis.

Synthesis of Monocyte-targeting Peptide Amphiphile Micelles for Imaging of Atherosclerosis

Atherosclerosis is a major contributor to cardiovascular disease, the leading cause of death worldwide, which claims 17.3 million lives annually. Atherosclerosis is also the leading cause of sudden death and myocardial infarction, instigated by unstable plaques that rupture and occlude the blood vessel without warning. Current imaging modalities cannot differentiate between stable and unstable plaques that rupture. Peptide amphiphiles micelles (PAMs) can overcome this drawback as they can be modified with a variety of targeting moieties that bind specifically to diseased tissue. Monocytes have been shown to be early markers of atherosclerosis, while large accumulation of monocytes is associated with plaques prone to rupture. Hence, nanoparticles that can target monocytes can be used to discriminate different stages of atherosclerosis. To that end, here, we describe a protocol for the preparation of monocyte-targeting PAMs (monocyte chemoattractant protein-1 (MCP-1) PAMs). MCP-1 PAMs are self-assembled through synthesis under mild conditions to form nanoparticles of 15 nm in diameter with near neutral surface charge. In vitro, PAMs were found to be biocompatible and had a high binding affinity for monocytes. The methods described herein show promise for a wide range of applications in atherosclerosis as well as other inflammatory diseases.

Protein Mimetic and Anticancer Properties of Monocyte-Targeting Peptide Amphiphile Micelles

Monocyte chemoattractant protein-1 (MCP-1) stimulates the migration of monocytes to inflammatory sites, leading to the progression of many diseases. Recently, we described a monocyte-targeting peptide amphiphile micelle (MCP-1 PAM) incorporated with the chemokine receptor CCR2 binding motif of MCP-1, which has a high affinity for monocytes in atherosclerotic plaques. We further report here the biomimetic components of MCP-1 PAMs and the influence of the nanoparticle upon binding to monocytes. We report that MCP-1 PAMs have enhanced secondary structure compared to the MCP-1 peptide. As a result, MCP-1 PAMs displayed improved binding and chemoattractant properties to monocytes, which upregulated the inflammatory signaling pathways responsible for monocyte migration. Interestingly, when MCP-1 PAMs were incubated in the presence of prostate cancer cells in vitro, the particle displayed anticancer efficacy by reducing CCR2 expression. Given that monocytes play an important role in tumor cell migration and invasion, our results demonstrate that PAMs can improve the native biofunctional properties of the peptide and may be used as an effective inhibitor to prevent chemokine-receptor interactions that promote disease progression.

Self-assembling peptide-based building blocks in medical applications

Peptides and peptide-conjugates, comprising natural and synthetic building blocks, are an increasingly popular class of biomaterials. Self-assembled nanostructures based on peptides and peptide-conjugates offer advantages such as precise selectivity and multifunctionality that can address challenges and limitations in the clinic. In this review article, we discuss recent developments in the design and self-assembly of various nanomaterials based on peptides and peptide-conjugates for medical applications, and categorize them into two themes based on the driving forces of molecular self-assembly. First, we present the self-assembled nanostructures driven by the supramolecular interactions between the peptides, with or without the presence of conjugates. The studies where nanoassembly is driven by the interactions between the conjugates of peptide-conjugates are then presented. Particular emphasis is given to in vivo studies focusing on therapeutics, diagnostics, immune modulation and regenerative medicine. Finally, challenges and future perspectives are presented.

Targeting cell adhesion molecules with nanoparticles using in vivo and flow-based in vitro models of atherosclerosis

Atherosclerosis is a leading cause of death worldwide; in addition to lipid dysfunction, chronic arterial wall inflammation is a key component of atherosclerosis. Techniques that target cell adhesion molecules, which are overexpressed during inflammation, are effective methods to detect and treat atherosclerosis. Specifically, research groups have identified vascular cell adhesion molecule-1, intercellular adhesion molecule-1, platelet endothelial cell adhesion molecule, and selectins (E-selectin and P-selectin) as correlated to atherogenesis. In this review, we discuss recent strategies both in vivo and in vitro that target cell adhesion molecules. First, we discuss peptide-based and antibody (Ab)-based nanoparticles utilized in vivo for diagnostic, therapeutic, and theranostic applications. Second, we discuss flow-based in vitro models that serve to reduce the traditional disadvantages of in vivo studies such as variability, time to develop the disease, and ethical burden, but preserve physiological relevance. The knowledge gained from these targeting studies can be translated into clinical solutions for improved detection, prevention, and treatment of atherosclerosis. Impact statement As atherosclerosis remains the leading cause of death, there is an urgent need to develop better tools for treatment of the disease. The ability to improve current treatments relies on enhancing the accuracy of in vitro and in vivo atherosclerotic models. While in vivo models provide all the relevant testing parameters, variability between animals and among models used is a barrier to reproducible results and comparability of NP efficacy. In vitro cultures isolate cells into microenvironments that fail to take into account flow separation and shear stress, which are characteristics of atherosclerotic lesions. Flow-based in vitro models provide more physiologically relevant platforms, bridging the gap between in vivo and 2D in vitro models. This is the first review that presents recent advances regarding endothelial cell-targeting using adhesion molecules in light of in vivo and flow-based in vitro models, providing insights for future development of optimal strategies against atherosclerosis.

Nanotechnology, a new paradigm in atherosclerosis treatment

Atherosclerosis, a known and prevalent disease, causes progressive deterioration of affected vessels, inducing a blood flow reduction with different complications, and its symptoms usually manifest in advanced stages of the disease. Therefore, the classic therapeutic alternatives are insufficient because the damages are many times irreversible. For this reason, there is a need to implement intelligent forms of drug administration and develop new therapeutic targets that reduce the progression of atherosclerotic lesion. The implementation of new tools for prevention, diagnosis and treatment of this cardiovascular disease is of special interest, focusing our attention on achieving a more effective control of the immune system. Finally, this review highlights the latest knowledge about nanotechnology as a powerful, modern, and promising therapeutic alternative applied to atherosclerotic disease, as well as warning of the potential complications with their use.

Gadolinium-Functionalized Peptide Amphiphile Micelles for Multimodal Imaging of Atherosclerotic Lesions

The leading causes of morbidity and mortality globally are cardiovascular diseases, and nanomedicine can provide many improvements including disease-specific targeting, early detection, and local delivery of diagnostic agents. To this end, we designed fibrin-binding, peptide amphiphile micelles (PAMs), achieved by incorporating the targeting peptide cysteine-arginine-glutamic acid-lysine-alanine (CREKA), with two types of amphiphilic molecules containing the gadoliniuim (Gd) chelator diethylenetriaminepentaacetic acid (DTPA), DTPA-bis(stearylamide)(Gd), and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[(poly(ethylene glycol) (PEG))-2000]-DTPA(Gd) (DSPE-PEG2000-DTPA(Gd)). The material characteristics of the resulting nanoparticle diagnostic probes, clot-binding properties in vitro, and contrast enhancement and safety for dual, optical imaging-magnetic resonance imaging (MRI) were evaluated in the atherosclerotic mouse model. Transmission electron micrographs showed a homogenous population of spherical micelles for formulations containing DSPE-PEG2000-DTPA(Gd), whereas both spherical and cylindrical micelles were formed upon mixing DTPA-BSA(Gd) and CREKA amphiphiles. Clot-binding assays confirmed DSPE-PEG2000-DTPA(Gd)-based CREKA micelles targeted clots over 8-fold higher than nontargeting (NT) counterpart micelles, whereas no difference was found between CREKA and NT, DTPA-BSA(Gd) micelles. However, in vivo MRI and optical imaging studies of the aortas and hearts showed fibrin specificity was conferred by the peptide ligand without much difference between the nanoparticle formulations or shapes. Biodistribution studies confirmed that all micelles were cleared through both the reticuloendothelial system and renal clearance, and histology showed no signs of necrosis. In summary, these studies demonstrate the successful synthesis, and the molecular imaging capabilities of two types of CREKA-Gd PAMs for atherosclerosis. Moreover, we demonstrate the differences in micelle formulations and shapes and their outcomes in vitro versus in vivo for site-specific, diagnostic strategies, and provide the groundwork for the detection of thrombosis via contrast-enhancing agents and concurrent therapeutic delivery for theranostic applications.

Cytokines: roles in atherosclerosis disease progression and potential therapeutic targets

Atherosclerosis, the primary cause of cardiovascular disease (CVD), is a chronic inflammatory disorder in the walls of medium and large arteries. CVD is currently responsible for about one in three global deaths and this is expected to rise in the future due to an increase in the prevalence of obesity and diabetes. Current therapies for atherosclerosis mainly modulate lipid homeostasis and while successful at reducing the risk of a CVD-related death, they are associated with considerable residual risk and various side effects. There is, therefore, a need for alternative therapies aimed at regulating inflammation in order to reduce atherogenesis. This review will highlight the key role cytokines play during disease progression as well as potential therapeutic strategies to target them.