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

TPM2 as a potential predictive biomarker for atherosclerosis

Cardiac-cerebral vascular disease (CCVD), is primarily induced by atherosclerosis, and is a leading cause of mortality. Numerous studies have investigated and attempted to clarify the molecular mechanisms of atherosclerosis; however, its pathogenesis has yet to be completely elucidated. Two expression profiling datasets, GSE43292 and GSE57691, were obtained from the Gene Expression Omnibus (GEO) database. The present study then identified the differentially expressed genes (DEGs), and functional annotation of the DEGs was performed. Finally, an atherosclerosis animal model and neural network prediction model was constructed to verify the relationship between hub gene and atherosclerosis. The results identified a total of 234 DEGs between the normal and atherosclerosis samples. The DEGs were mainly enriched in actin filament, actin binding, smooth muscle cells, and cytokine-cytokine receptor interactions. A total of 13 genes were identified as hub genes. Following verification of animal model, the common DEG, Tropomyosin 2 (TPM2), was found, which were displayed at lower levels in the atherosclerosis models and samples. In summary, DEGs identified in the present study may assist clinicians in understanding the pathogenesis governing the occurrence and development of atherosclerosis, and TPM2 exhibits potential as a promising diagnostic and therapeutic biomarker for atherosclerosis.

The Microbial Metabolite Trimethylamine N-Oxide Links Vascular Dysfunctions and the Autoimmune Disease Rheumatoid Arthritis

Diet and microbiota each have a direct impact on many chronic, inflammatory, and metabolic diseases. As the field develops, a new perspective is emerging. The effects of diet may depend on the microbiota composition of the intestine. A diet that is rich in choline, red meat, dairy, or egg may promote the growth, or change the composition, of microbial species. The microbiota, in turn, may produce metabolites that increase the risk of cardiovascular disease. This article reviews our current understanding of the effects of the molecule trimethylamine-N-oxide (TMAO) obtained from food or produced by the microbiota. We review the mechanisms of actions of TMAO, and studies that associate it with cardiovascular and chronic kidney diseases. We introduce a novel concept: TMAO is one among a group of selective uremic toxins that may rise to high levels in the circulation or accumulate in various organs. Based on this information, we evaluate how TMAO may harm, by exacerbating inflammation, or may protect, by attenuating amyloid formation, in autoimmune diseases such as rheumatoid arthritis.

Functional Role of VCAM-1 Targeted Flavonoid-Loaded Lipid Nanoemulsions in Reducing Endothelium Inflammation

Citrus flavonoids have well-documented protective effects on cardiovascular system, but the poor water solubility and reduced bioavailability restrict their therapeutic use. We aimed to overcome these limitations and encapsulated naringenin and hesperetin into lipid nanoemulsions (LNs), targeted to vascular cell adhesion molecule-1 (VCAM-1), which is expressed on activated endothelial cells (ECs). LNs were characterized by a hydrodynamic size of ~200 nm, negative zeta potential, an encapsulation efficiency of flavonoids higher than 80%, good in vitro stability and steady release of the cargo. The LNs were neither cytotoxic to human ECs line EA.hy926, nor provoked in vitro lysis of murine erithrocytes. Then, we tested whether these nanoformulations reduce tumor necrosis factor-alpha (TNF-α) induced EC-activation. We found that flavonoid-loaded LNs, either non-targeted or targeted to the endothelium, were taken up by the EA.hy926 cells in a dose-dependent manner, but dependent on TNF-α only in the case of endothelium-targeted LNs. Moreover, these nanoparticles inhibited both the adhesion and transmigration of THP-1 monocytes on/through activated ECs, by mechanisms involving a reduced expression of the pro-inflammatory chemokine monocyte chemotactic protein 1 (MCP-1) and diminished nuclear translocation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB).

Probing cell-nanoparticle (cubosome) interactions at the endothelial interface: do tissue dimension and flow matter?

In the research field of nanostructured systems for biomedical applications, increasing attention has been paid to using biomimetic, dynamic cellular models to adequately predict their bio-nano behaviours. This work specifically evaluates the biointeractions of nanostructured lipid-based particles (cubosomes) with human vascular cells from the aspects of tissue dimension (conventional 2D well plate versus 3D dynamic tubular vasculature) and shear flow effect (static, venous and arterial flow-mimicking conditions). A glass capillary-hosted, 3D tubular endothelial construct was coupled with circulating luminal fluid flow to simulate the human vascular systems. In the absence of fluid flow, the degree of cell-cubosome association was not significantly different between the 2D planar and the 3D tubular systems. Under flow conditions simulating venous (0.8 dynes per cm²) and arterial (10 dynes per cm²) shear stresses, the cell-cubosome association notably declined by 50% and 98%, respectively. This highlights the significance of shear-guided biointeractions of non-targeted nanoparticles in the circulation. Across all 2D and 3D cellular models with and without flow, cubosomes had little effect on the cell-cell contact based on the unchanged immunoexpression of the endothelial-specific intercellular junction marker PECAM-1. Interestingly, there were dissimilar nanoparticle distribution patterns between the 2D planar (showing discrete punctate staining) and the 3D tubular endothelium (with a more diffused, patchy fashion). Taken together, these findings highlight the importance of tissue dimension and shear flow in governing the magnitude and feature of cell-nanoparticle interactions.

Cardiovascular disease models: A game changing paradigm in drug discovery and screening

Cardiovascular disease is the leading cause of death worldwide. Although investment in drug discovery and development has been sky-rocketing, the number of approved drugs has been declining. Cardiovascular toxicity due to therapeutic drug use claims the highest incidence and severity of adverse drug reactions in late-stage clinical development. Therefore, to address this issue, new, additional, replacement and combinatorial approaches are needed to fill the gap in effective drug discovery and screening. The motivation for developing accurate, predictive models is twofold: first, to study and discover new treatments for cardiac pathologies which are leading in worldwide morbidity and mortality rates; and second, to screen for adverse drug reactions on the heart, a primary risk in drug development. In addition to in vivo animal models, in vitro and in silico models have been recently proposed to mimic the physiological conditions of heart and vasculature. Here, we describe current in vitro, in vivo, and in silico platforms for modelling healthy and pathological cardiac tissues and their advantages and disadvantages for drug screening and discovery applications. We review the pathophysiology and the underlying pathways of different cardiac diseases, as well as the new tools being developed to facilitate their study. We finally suggest a roadmap for employing these non-animal platforms in assessing drug cardiotoxicity and safety.

High glucose-induced endothelial microparticles increase adhesion molecule expression on endothelial cells

The experimental aim of this study was to determine, in vitro, the effects of glucose-induced EMPs on endothelial cell expression of E-selectin, intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 and platelet cell adhesion molecule-1 (PECAM-1). Human umbilical vein endothelial cells (HUVECs) were cultured (3rd passage) and plated in 6-well plates at a density of 5.0 × 105 cells/condition. HUVECs were incubated with media containing either 25 mM d-glucose (concentration representing a hyperglycemic state) or 5 mM d-glucose (normoglycemic condition) for 48 h to generate EMPs. EMP identification (CD144+) and concentration were determined by flow cytometry. HUVECs (3 × 106 cells/condition) were treated with either high glucose-derived EMPs (hgEMPs) or normal glucose-derived (ngEMPs) for 24 h and surface expression of E-selectin (CD62E-PE), ICAM-1 (CD54-FITC), VCAM-1 (CD106-APC) and PECAM-1 (CD31-BV) was assessed by flow cytometry and reported as mean fluorescent intensity (MFI). Hyperglycemic-derived EMPs induced significantly higher surface expression of E-selectin (2614 ± 132 vs. 2010 ± 204 MFI), ICAM-1 (2110 ± 81 vs. 1688 ± 152 MFI), VCAM-1 (3589 ± 431 vs. 2134 ± 386) and PECAM-1 (4237 ± 395 vs. 2525 ± 269 MFI) on endothelial cells than EMPs from normoglycemic conditions. Microparticle-induced cell adhesion molecule expression provides potential novel mechanistic insight regarding the accelerated risk of atherosclerotic vascular disease associated with hyperglycemia.

Calcium-binding nanoparticles for vascular disease

Cardiovascular disease (CVD) including atherosclerosis is the leading cause of death worldwide. As CVDs and atherosclerosis develop, plaques begin to form in the blood vessels and become calcified. Calcification within the vasculature and atherosclerotic plaques have been correlated with rupture and consequently, acute myocardial infarction. However, current imaging methods to identify vascular calcification have limitations in determining plaque composition and structure. Nanoparticles can overcome these limitations due to their versatility and ability to incorporate a wide range of targeting and contrast agents. In this review, we summarize the current understanding of calcification in atherosclerosis, their role in instigating plaque instability, and clinical methodologies to detect and analyze vascular calcification. In addition, we highlight the potential of calcium-targeting ligands and nanoparticles to create novel calcium-detecting tools.

Rapamycin: A Bacteria-Derived Immunosuppressant That Has Anti-atherosclerotic Effects and Its Clinical Application

Atherosclerosis (AS) is the leading cause of stroke and death worldwide. Although many lipid-lowering or antiplatelet medicines have been used to prevent the devastating outcomes caused by AS, the serious side effects of these medicines cannot be ignored. Moreover, these medicines are aimed at preventing end-point events rather than addressing the formation and progression of the lesion. Rapamycin (sirolimus), a fermentation product derived from soil samples, has immunosuppressive and anti-proliferation effects. It is an inhibitor of mammalian targets of rapamycin, thereby stimulating autophagy pathways. Several lines of evidence have demonstrated that rapamycin possess multiple protective effects against AS through various molecular mechanisms. Moreover, it has been used successfully as an anti-proliferation agent to prevent in-stent restenosis or vascular graft stenosis in patients with coronary artery disease. A thorough understanding of the biomedical regulatory mechanism of rapamycin in AS might reveal pathways for retarding AS. This review summarizes the current knowledge of biomedical mechanisms by which rapamycin retards AS through action on various cells (endothelial cells, macrophages, vascular smooth muscle cells, and T-cells) in early and advanced AS and describes clinical and potential clinical applications of the agent.

Strategies for Targeted Delivery to the Peripheral Nerve

Delivery of compounds to the peripheral nervous system has the potential to be used as a treatment for a broad range of conditions and applications, including neuropathic pain, regional anesthesia, traumatic nerve injury, and inherited and inflammatory neuropathies. However, efficient delivery of therapeutic doses can be difficult to achieve due to peripheral neuroanatomy and the restrictiveness of the blood-nerve barrier. Depending on the underlying integrity of the blood-nerve barrier in the application at hand, several strategies can be employed to navigate the peripheral nerve architecture and facilitate targeted delivery to the peripheral nerve. This review describes different applications where targeted delivery to the peripheral nervous system is desired, the challenges that the blood-nerve barrier poses in each application, and bioengineering strategies that can facilitate delivery in each application.

Hybrid, metal oxide-peptide amphiphile micelles for molecular magnetic resonance imaging of atherosclerosis

Background

Atherosclerosis, a major source of cardiovascular disease, is asymptomatic for decades until the activation of thrombosis and the rupture of enlarged plaques, resulting in acute coronary syndromes and sudden cardiac arrest. Magnetic resonance imaging (MRI) is a noninvasive nuclear imaging technique to assess the degree of atherosclerotic plaque with high spatial resolution and excellent soft tissue contrast. However, MRI lacks sensitivity for preventive medicine, which limits the ability to observe the onset of vulnerable plaques. In this study, we engineered hybrid metal oxide-peptide amphiphile micelles (HMO-Ms) that combine an inorganic, magnetic iron oxide or manganese oxide inner core with organic, fibrin-targeting peptide amphiphiles, consisting of the sequence CREKA, for potential MRI imaging of thrombosis on atherosclerotic plaques.

Results

Hybrid metal oxide-peptide amphiphile micelles, consisting of an iron oxide (Fe-Ms) or manganese oxide (Mn-Ms) core with CREKA peptides, were self-assembled into 20–30 nm spherical nanoparticles, as confirmed by dynamic light scattering and transmission electron microscopy. These hybrid nanoparticles were found to be biocompatible with human aortic endothelial cells in vitro, and HMO-Ms bound to human clots three to five times more efficiently than its non-targeted counterparts. Relaxivity studies showed ultra-high r₂ value of 457 mM⁻¹ s⁻¹ and r₁ value of 0.48 mM⁻¹ s⁻¹ for Fe-Ms and Mn-Ms, respectively. In vitro, MR imaging studies demonstrated the targeting capability of CREKA-functionalized hybrid nanoparticles with twofold enhancement of MR signals.

Conclusion

This novel hybrid class of MR agents has potential as a non-invasive imaging method that specifically detects thrombosis during the pathogenesis of atherosclerosis.

Electronic supplementary material

The online version of this article (10.1186/s12951-018-0420-8) contains supplementary material, which is available to authorized users.

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.

Biomarker Profiling of Neurovascular Diseases in Patients with Stage 5 Chronic Kidney Disease

Patients with stage 5 chronic kidney disease (CKD5D) have a higher risk of developing neurocognitive deficits. Stroke, cervical carotid artery disease (CCAD), and intracranial atherosclerotic disease (ICAD) are causes of such deficits in CKD5D. Chronic inflammation from renal failure elevates risk for these diseases through oxidative stress and vascular dysfunction. The adverse impact on the carotid and intracranial vasculatures contributes to the multifactorial pathophysiology of stroke. Eleven plasma biomarker levels in patients with CKD5D (n = 97) and healthy controls (n = 17-50) were measured using sandwich enzyme-linked immunosorbent assay (ELISA) method. Of the 97 patients with CKD5D, 24 had CCAD, 19 had ICAD, and 23 had acute stroke. Elevations in NACHT, LRR, and PYD domains-containing protein 3 (NALP3) levels in patients with CKD5D (+)CCAD (1.80 ± 0.11 ng/mL) compared to patients with (−)CCAD (1.55 ± 0.08 ng/mL) were statistically significant (P = .0299). Differences in D-dimer levels were also found to be statistically significant (P = .0258) between CKD5D (+)stroke (1.83 ± 0.42 μg/mL) and (−)stroke (0.89 ± 0.13 μg/mL) groups. The ages of the (+) neurovascular disease groups were found to be significantly elevated compared to the (−) neurovascular disease groups (P = .0002 carotid AD; P < .0001 ICAD; P = .0157 stroke). D-dimer levels were positively correlated with age in CKD5D (P = .0375). With the possible exception of NALP3 for CCAD, profiling levels of specific biomarkers for risk stratification of neurovascular diseases in the CKD5D population warrants further investigation.

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.

Biomimetic nanoparticles for inflammation targeting

There have been many recent exciting developments in biomimetic nanoparticles for biomedical applications. Inflammation, a protective response involving immune cells, blood vessels, and molecular mediators directed against harmful stimuli, is closely associated with many human diseases. As a result, biomimetic nanoparticles mimicking immune cells can help achieve molecular imaging and precise drug delivery to these inflammatory sites. This review is focused on inflammation-targeting biomimetic nanoparticles and will provide an in-depth look at the design of these nanoparticles to maximize their benefits for disease diagnosis and treatment.

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.

ICAM-1 targeting, intracellular trafficking, and functional activity of polymer nanocarriers coated with a fibrinogen-derived peptide for lysosomal enzyme replacement

Enzyme replacement is a viable treatment for diseases caused by genetic deficiency of lysosomal enzymes. However, suboptimal access of enzymes to target sites limits this strategy. Polymer nanocarriers (NCs) coated with antibody against intercellular adhesion molecule 1 (ICAM-1), a protein overexpressed on most cells under disease states, enhanced biodistribution and lysosomal delivery of these therapeutics. Whether this can be achieved using more biocompatible ICAM-1-targeting moieties is unknown, since intracellular uptake via this route is sensitive to the receptor epitope being targeted. We examined this using polymer NCs coated with an ICAM-1-targeting peptide derived from the fibrinogen sequence. Scrambled-sequence peptide and anti-ICAM were used as controls. NCs carried acid sphingomyelinase (ASM), used for treatment of type B Niemann-Pick disease, and fluorescence microscopy was employed to examine cellular performance. Peptide-coated/enzyme NCs efficiently targeted ICAM-1 (22-fold over non-specific counterparts; B_max ∼180 NCs/cell; t_1/2 ∼28 min), recognised human and mouse cells (1.2- to 0.7-fold binding vs. antibody/enzyme NCs), were efficiently endocytosed (71% at 1 h chase), and trafficked to lysosomes (30--45% of internalised NCs; 2 h chase). This restored lysosomal levels of sphingomyelin and cholesterol within 5 h chase (∼95% reduction over disease levels), similar to antibody-enzyme NCs. This fibrinogen-derived ICAM-1-targeting peptide holds potential for lysosomal enzyme replacement therapy.