Extracellular vesicles through the blood-brain barrier: a review.

Extracellular vesicles (EVs) are particles naturally released from cells that are delimited by a lipid bilayer and are unable to replicate. How the EVs cross the Blood-Brain barrier (BBB) in a bidirectional manner between the bloodstream and brain parenchyma remains poorly understood. Most in vitro models that have evaluated this event have relied on monolayer transwell or microfluidic organ-on-a-chip techniques that do not account for the combined effect of all cellular layers that constitute the BBB at different sites of the Central Nervous System. There has not been direct transcytosis visualization through the BBB in mammals in vivo, and evidence comes from in vivo experiments in zebrafish. Literature is scarce on this topic, and techniques describing the mechanisms of EVs motion through the BBB are inconsistent. This review will focus on in vitro and in vivo methodologies used to evaluate EVs transcytosis, how EVs overcome this fundamental structure, and discuss potential methodological approaches for future analyses to clarify these issues. Understanding how EVs cross the BBB will be essential for their future use as vehicles in pharmacology and therapeutics.

Peptide Targeted Gold Nanoplatform Carrying miR-145 Induces Antitumoral Effects in Ovarian Cancer Cells.

One of the recent attractive therapeutic approaches for cancer treatment is restoring downregulated microRNAs. They play an essential muti-regulatory role in cellular processes such as proliferation, differentiation, survival, apoptosis, cell cycle, angiogenesis, and metastasis, among others. In this study, a gold nanoplatform (GNPF) carrying miR-145, a downregulated microRNA in many cancer types, including epithelial ovarian cancer, was designed and synthesized. For targeting purposes, the GNPF was functionalized with the FSH33 peptide, which provided selectivity for ovarian cancer, and loaded with the miR-145 to obtain the nanosystem GNPF-miR-145. The GNPF-mir-145 was selectively incorporated in A2780 and SKOV3 cells and significantly inhibited cell viability and migration and exhibited proliferative and anchor-independent growth capacities. Moreover, it diminished VEGF release and reduced the spheroid size of ovarian cancer through the damage of cell membranes, thus decreasing cell viability and possibly activating apoptosis. These results provide important advances in developing miR-based therapies using nanoparticles as selective vectors and provide approaches for in vivo evaluation.

Development of a Nanostructured Lipid Carrier (NLC) by a Low-Energy Method, Comparison of Release Kinetics and Molecular Dynamics Simulation.

Lipid nanocarriers have a great potential for improving the physicochemical characteristics and behavior of poorly water-soluble drugs, such as aqueous dispersibility and oral bioavailability. This investigation presents a novel nanostructured lipid carrier (NLC) based on a mixture of solid lipid glycerides, fatty acid esters of PEG 1500 (Gelucire® 44/14), and an oil mix composed of capric and caprylic triglycerides (Miglyol® 812). These NLCs were developed by a simple low-energy method based on melt emulsification to yield highly encapsulating and narrowly distributed nanoparticles (~100 nm, PdI = 0.1, and zeta potential = ~-10 mV). Rhodamine 123 was selected as a poorly water-soluble drug model and owing to its spectroscopic properties. The novel NLCs were characterized by dynamic light scattering (DLS), zeta potential, nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and colloidal stability. The drug release was determined through a dialysis bag and vertical Franzs' cells to provide insights about the methods' suitability, revealing similar performance regardless of their different fluid dynamics. Rhodamine 123 followed a characteristic biphasic release profile owing to the swelling of the hydrophilic polymer coating and diffusion process from the lipid core as revealed by the Korsmeyers-Peppas kinetic modeling. Moreover, to elucidate the formation and incorporation of Rhodamine 123 into the NLC core, several molecular dynamics simulations were conducted. The temperature was shown to be an important condition to improve the formation of the nanoparticles. In addition, the liquid lipid incorporation to the formulation forms nanoparticles with imperfect centers, in contrast to nanoparticles without it. Moreover, Miglyol® 812 improves hydrophobic molecule solubility. These results suggest the potential of novel NLC as a drug delivery system for poorly water-soluble drugs.

Chitosan-Based Nanoparticles for Intracellular Delivery of ISAV Fusion Protein cDNA into Melanoma Cells: A Path to Develop Oncolytic Anticancer Therapies.

Oncolytic virus therapy has been tested against cancer in preclinical models and clinical assays. Current evidence shows that viruses induce cytopathic effects associated with fusogenic protein-mediated syncytium formation and immunogenic cell death of eukaryotic cells. We have previously demonstrated that tumor cell bodies generated from cells expressing the fusogenic protein of the infectious salmon anemia virus (ISAV-F) enhance crosspriming and display prophylactic antitumor activity against melanoma tumors. In this work, we evaluated the effects of the expression of ISAV-F on the B16 melanoma model, both in vitro and in vivo, using chitosan nanoparticles as transfection vehicle. We confirmed that the transfection of B16 tumor cells with chitosan nanoparticles (NP-ISAV) allows the expression of a fusogenically active ISAV-F protein and decreases cell viability because of syncytium formation in vitro. However, the in vivo transfection induces a delay in tumor growth, without inducing changes on the lymphoid populations in the tumor and the spleen. Altogether, our observations show that expression of ISAV fusion protein using chitosan nanoparticles induces cell fusion in melanoma cells and slight antitumor response.

Gold nanoparticle based double-labeling of melanoma extracellular vesicles to determine the specificity of uptake by cells and preferential accumulation in small metastatic lung tumors.

BACKGROUND: Extracellular vesicles (EVs) have shown great potential for targeted therapy, as they have a natural ability to pass through biological barriers and, depending on their origin, can preferentially accumulate at defined sites, including tumors. Analyzing the potential of EVs to target specific cells remains challenging, considering the unspecific binding of lipophilic tracers to other proteins, the limitations of fluorescence for deep tissue imaging and the effect of external labeling strategies on their natural tropism. In this work, we determined the cell-type specific tropism of B16F10-EVs towards cancer cell and metastatic tumors by using fluorescence analysis and quantitative gold labeling measurements. Surface functionalization of plasmonic gold nanoparticles was used to promote indirect labeling of EVs without affecting size distribution, polydispersity, surface charge, protein markers, cell uptake or in vivo biodistribution. Double-labeled EVs with gold and fluorescent dyes were injected into animals developing metastatic lung nodules and analyzed by fluorescence/computer tomography imaging, quantitative neutron activation analysis and gold-enhanced optical microscopy. RESULTS: We determined that B16F10 cells preferentially take up their own EVs, when compared with colon adenocarcinoma, macrophage and kidney cell-derived EVs. In addition, we were able to detect the preferential accumulation of B16F10 EVs in small metastatic tumors located in lungs when compared with the rest of the organs, as well as their precise distribution between tumor vessels, alveolus and tumor nodules by histological analysis. Finally, we observed that tumor EVs can be used as effective vectors to increase gold nanoparticle delivery towards metastatic nodules. CONCLUSIONS: Our findings provide a valuable tool to study the distribution and interaction of EVs in mice and a novel strategy to improve the targeting of gold nanoparticles to cancer cells and metastatic nodules by using the natural properties of malignant EVs.

Intranasal delivery of mesenchymal stem cell-derived exosomes reduces oxidative stress and markedly inhibits ethanol consumption and post-deprivation relapse drinking.

Chronic ethanol consumption leads to brain oxidative stress and neuroinflammation, conditions known to potentiate and perpetuate each other. Several studies have shown that neuroinflammation results in increases in chronic ethanol consumption. Recent reports showed that the intra-cerebroventricular administration of mesenchymal stem cells to rats consuming alcohol chronically markedly inhibited oxidative-stress, abolished neuroinflammation and greatly reduced chronic alcohol intake and post deprivation relapse-like alcohol intake. However, the intra-cerebroventricular administration of living cells is not suitable as a treatment of a chronic condition. The present study aimed at inhibiting ethanol intake by the non-invasive intranasal administration of human mesenchymal stem cell products: exosomes, microvesicles (40 to 150 nm) with marked antioxidant activity extruded from mesenchymal stem cells. The exosome membrane can fuse with the plasma membrane of cells in different tissues, thus delivering their content intracellularly. The study showed that the weekly intranasal administration of mesenchymal stem cell-derived exosomes to rats consuming alcohol chronically (1) inhibited their ethanol intake by 84 percent and blunted the relapse-like 'binge' drinking that follows an alcohol deprivation period and ethanol re-access. (2) Intranasally administered exosomes were found in the brain within 24 hours; (3) fully reversed both alcohol-induced hippocampal oxidative-stress, evidenced by a lower ratio of oxidized to reduced glutathione, and neuroinflammation, shown by a reduced astrocyte activation and microglial density; and (4) increased glutamate transporter GLT1 expression in nucleus accumbens, counteracting the inhibition of glutamate transporter activity, reportedly depressed under oxidative-stress conditions. Possible translational implications are envisaged.

The antinociceptive effect of resveratrol in bone cancer pain is inhibited by the Silent Information Regulator 1 inhibitor selisistat.

OBJECTIVES: To study the antinociceptive effect of single and repeated doses of resveratrol in a bone cancer pain model, and whether this effect is prevented by the Silent Information Regulator 1 (SIRT1) inhibitor selisistat. METHODS: The femoral intercondylar bone of BALB/c mice was injected with 1 000 000 BJ3Z cancer cells. Bone resorption and tumour mass growth (measured by in vivo X-ray and fluorescence imaging), as well as mechanical nociceptive thresholds (von Frey device) and dynamic functionality (rotarod machine), were evaluated during the following 4 weeks. Acute resveratrol (100 mg/kg i.p.) and/or selisistat (10 mg/kg s.c.) were administered on day 14. Chronic resveratrol (100 mg/kg i.p., daily) and/or selisistat (0.5 µg/h s.c., Alzet pump) were administered between days 14 and 20. KEY FINDINGS: Tumour growth gradually incremented until day 31, while mechanical hyperalgesia started on day 3 after cancer cell injection. Acute resveratrol increased the mechanical threshold of pain (peaking at 1.5 h), while the dynamic functionality decreased. Chronic resveratrol produced a sustained antinociceptive effect on mechanical hyperalgesia and improved the loss of dynamic functionality induced by the bone cancer tumour. Selisistat prevented all the effects of resveratrol. CONCLUSIONS: Acute and chronic resveratrol induces antinociceptive effect in the model of metastatic osseous oncological pain, an effect that would be mediated by SIRT1 molecular signalling.

Stability of Antibacterial Silver Carboxylate Complexes against Staphylococcus epidermidis and Their Cytotoxic Effects.

The antibacterial effects against Staphylococcus epidermidis of five silver carboxylate complexes with anti-inflammatory ligands were studied in order to analyze and compare them in terms of stability (in solution and after exposure to UV light), and their antibacterial and morphological differences. Four effects of the Ag-complexes were evidenced by transmission electronic microscopy (TEM) and scanning electronic microscopy (SEM): DNA condensation, membrane disruption, shedding of cytoplasmic material and silver compound microcrystal penetration of bacteria. 5-Chlorosalicylic acid (5Cl) and sodium 4-aminosalicylate (4A) were the most effective ligands for synthesizing silver complexes with high levels of antibacterial activity. However, Ag-5Cl was the most stable against exposure UV light (365 nm). Cytotoxic effects were tested against two kinds of eukaryotic cells: murine fibroblast cells (T10 1/2) and human epithelial ovarian cancer cells (A2780). The main objective was to identify changes in their antibacterial properties associated with potential decomposition and the implications for clinical applications.

A New Kind of Quinonic-Antibiotic Useful Against Multidrug-Resistant S. aureus and E. faecium Infections.

A rapid emergence of resistant bacteria is occurring worldwide, endangering the efficacy of antibiotics and reducing the therapeutic arsenal available for treatment of infectious diseases. In the present study, we developed a new class of compounds with antibacterial activity obtained by a simple, two step synthesis and screened the products for in vitro antibacterial activity against ATCC® strains using the broth microdilution method. The compounds exhibited minimum inhibitory concentrations (MIC) of 1⁻32 µg/mL against Gram-positive ATCC® strains. The structure⁻activity relationship indicated that the thiophenol ring is essential for antibacterial activity and the substituents on the thiophenol ring module, for antibacterial activity. The most promising compounds detected by screening were tested against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VREF) clinical isolates. We found remarkable activity against VREF for compounds 7 and 16, were the MIC50/90 were 2/4 µg/mL and 4/4 µg/mL, respectively, while for vancomycin the MIC50/90 was 256/512 µg/mL. Neither compound affected cell viability in any of the mammalian cell lines at any of the concentrations tested. These in vitro data show that compounds 7 and 16 have an interesting potential to be developed as new antibacterial drugs against infections caused by VREF.

Encapsulation of Gold Nanostructures and Oil-in-Water Nanocarriers in Microgels with Biomedical Potential.

Here we report the incorporation of gold nanostructures (nanospheres or nanorods, functionalized with carboxylate-end PEG) and curcumin oil-in-water (O/W) nanoemulsions (CurNem) into alginate microgels using the dripping technique. While gold nanostructures are promising nanomaterials for photothermal therapy applications, CurNem possess important pharmacological activities as reported here. In this sense, we evaluated the effect of CurNem on cell viability of both cancerous and non-cancerous cell lines (AGS and HEK293T, respectively), demonstrating preferential toxicity in cancer cells and safety for the non-cancerous cells. After incorporating gold nanostructures and CurNem together into the microgels, microstructures with diameters of 220 and 540 µm were obtained. When stimulating microgels with a laser, the plasmon effect promoted a significant rise in the temperature of the medium; the temperature increase was higher for those containing gold nanorods (11⁻12 °C) than nanospheres (1⁻2 °C). Interestingly, the incorporation of both nanosystems in the microgels maintains the photothermal properties of the gold nanostructures unmodified and retains with high efficiency the curcumin nanocarriers. We conclude that these results will be of interest to design hydrogel formulations with therapeutic applications.

Improving gold nanorod delivery to the central nervous system by conjugation to the shuttle Angiopep-2.

AIM: To improve the in vivo delivery of gold nanorods (GNRs) to the central nervous system of rats, these gold nanoparticles were conjugated to Angiopep-2, a shuttle peptide that can cross the blood-brain barrier. MATERIALS & METHODS: GNRs were synthesized and modified using polyethylene glycol and Angiopep-2 (GNR-PEG-Angiopep-2). The physicochemical properties, in vitro cytotoxicity and ex vivo biodistribution of the conjugate were examined. RESULTS: GNR-PEG-Angiopep-2 was stable over the following days, and the different concentrations that were tested did not affect the viability of microvascular endothelial cells. The conjugation of Angiopep-2 to GNRs enhanced the endocytosis of these particles (in vitro) and the accumulation in brains (in vivo), when compared with GNRs modified only with PEG. CONCLUSION: This study provides evidence that Angiopep-2 improves the delivery of GNRs to the brain parenchyma. This property is highly relevant for future applications of GNRs as platforms for photothermal and theranostic purposes.