Intracellular Membrane Transport in Vascular Endothelial Cells.

The main component of blood and lymphatic vessels is the endothelium covering their luminal surface. It plays a significant role in many cardiovascular diseases. Tremendous progress has been made in deciphering of molecular mechanisms involved into intracellular transport. However, molecular machines are mostly characterized in vitro. It is important to adapt this knowledge to the situation existing in tissues and organs. Moreover, contradictions have accumulated within the field related to the function of endothelial cells (ECs) and their trans-endothelial pathways. This has induced necessity for the re-evaluation of several mechanisms related to the function of vascular ECs and intracellular transport and transcytosis there. Here, we analyze available data related to intracellular transport within ECs and re-examine several hypotheses about the role of different mechanisms in transcytosis across ECs. We propose a new classification of vascular endothelium and hypotheses related to the functional role of caveolae and mechanisms of lipid transport through ECs.

Broad-spectrum non-toxic antiviral nanoparticles with a virucidal inhibition mechanism.

Viral infections kill millions yearly. Available antiviral drugs are virus-specific and active against a limited panel of human pathogens. There are broad-spectrum substances that prevent the first step of virus-cell interaction by mimicking heparan sulfate proteoglycans (HSPG), the highly conserved target of viral attachment ligands (VALs). The reversible binding mechanism prevents their use as a drug, because, upon dilution, the inhibition is lost. Known VALs are made of closely packed repeating units, but the aforementioned substances are able to bind only a few of them. We designed antiviral nanoparticles with long and flexible linkers mimicking HSPG, allowing for effective viral association with a binding that we simulate to be strong and multivalent to the VAL repeating units, generating forces (∼190 pN) that eventually lead to irreversible viral deformation. Virucidal assays, electron microscopy images, and molecular dynamics simulations support the proposed mechanism.  These particles show no cytotoxicity, and in vitro nanomolar irreversible activity against herpes simplex virus (HSV), human papilloma virus, respiratory syncytial virus (RSV), dengue and lenti virus. They are active ex vivo in human cervicovaginal histocultures infected by HSV-2 and in vivo in mice infected with RSV.

Conformal coating by multilayer nano-encapsulation for the protection of human pancreatic islets: In-vitro and in-vivo studies.

To improve the efficiency of pancreatic islet transplantation, we performed in-vitro and in-vivo experiments with isolated human pancreatic islets coated by multi-layer nano-encapsulation using differently charged polymers [chitosan and poly(sodium styrene sulfonate)] to obtain up to 9 layers. The islet coating (thickness: 104.2 ±â€¯4.2 nm) was uniform, with ≥ 90% cell viability and well preserved beta- and alpha-cell ultrastructure. Nano-encapsulated islets maintained physiological glucose-stimulated insulin secretion by both static incubation and perifusion studies. Notably, palmitate- or cytokine-induced toxicity was significantly reduced in nano-coated islets. Xenotransplantation of nano-encapsulated islets under the kidney capsule of streptozotocin-induced C57Bl/6J diabetic mice allowed long term normal or near normal glycemia, associated with minimal infiltration of immune cell into the grafts, well preserved islet morphology and signs of re-vascularization. In summary, the multi-layer nano-encapsulation approach described in the present study provides a promising tool to effectively protect human islets both in-vitro andin-vivo conditions.

Fluorinated and Charged Hydrogenated Alkanethiolates Grafted on Gold: Expanding the Diversity of Mixed-Monolayer Nanoparticles for Biological Applications.

Low intrinsic toxicity, high solubility, and stability are important and necessary features of gold nanoparticles to be used in the biomedical field. In this context, charged nanoparticles proved to be very versatile, and among them charged mixed-monolayer gold nanoparticles, displaying monolayers with well-defined morphologies, represent a paradigm. By using mixtures of hydrogenated and fluorinated thiols, the formation of monolayer domains may be brought to an extreme because of the immiscibility of fluorinated and hydrogenated chains. Following this rationale, mixed monolayer gold nanoparticles featuring ammonium, sulfonate, or carboxylic groups on their surface were prepared by using amphiphilic hydrogenated thiols and 1H,1H,2H,2H-perfluoro-alkanethiols. The toxicity of these systems was assessed in HeLa cells and was found to be, in general, low even for the cationic nanoparticles which usually show a high cytotoxicity and is comparable to that of homoligand gold nanoparticles displaying amphiphilic-charge neutral-hydrogenated or fluorinated thiolates in their monolayer. These properties make the mixed ligand monolayer gold nanoparticles an interesting new candidate for medical application.

Superparamagnetic Nanoparticles as High Efficiency Magnetic Resonance Imaging T2 Contrast Agent.

Nanoparticle-based magnetic resonance imaging T2 negative agents are of great interest, and much effort is devoted to increasing cell-loading capability while maintaining low cytotoxicity. Herein, two classes of mixed-ligand protected magnetic-responsive, bimetallic gold/iron nanoparticles (Au/Fe NPs) synthesized by a two-step method are presented. Their structure, surface composition, and magnetic properties are characterized. The two classes of sulfonated Au/Fe NPs, with an average diameter of 4 nm, have an average atomic ratio of Au to Fe equal to 7 or 8, which enables the Au/Fe NPs to be superparamagnetic with a blocking temperature of 56 K and 96 K. Furthermore, preliminary cellular studies reveal that both Au/Fe NPs show very limited toxicity. MRI phantom experiments show that r2/r1 ratio of Au/Fe NPs is as high as 670, leading to a 66% reduction in T2 relaxation time. These nanoparticles provide great versatility and potential for nanoparticle-based diagnostics and therapeutic applications and as imaging contrast agents.

Protein corona: implications for nanoparticle interactions with pulmonary cells.

BACKGROUND: We previously showed that cerium oxide (CeO2), barium sulfate (BaSO4) and zinc oxide (ZnO) nanoparticles (NPs) exhibited different lung toxicity and pulmonary clearance in rats. We hypothesize that these NPs acquire coronas with different protein compositions that may influence their clearance from the lungs. METHODS: CeO2, silica-coated CeO2, BaSO4, and ZnO NPs were incubated in rat lung lining fluid in vitro. Then, gel electrophoresis followed by quantitative mass spectrometry was used to characterize the adsorbed proteins stripped from these NPs. We also measured uptake of instilled NPs by alveolar macrophages (AMs) in rat lungs using electron microscopy. Finally, we tested whether coating of gold NPs with albumin would alter their lung clearance in rats. RESULTS: We found that the amounts of nine proteins in the coronas formed on the four NPs varied significantly. The amounts of albumin, transferrin and α-1 antitrypsin were greater in the coronas of BaSO4 and ZnO than that of the two CeO2 NPs. The uptake of BaSO4 in AMs was less than CeO2 and silica-coated CeO2 NPs. No identifiable ZnO NPs were observed in AMs. Gold NPs coated with albumin or citrate instilled into the lungs of rats acquired the similar protein coronas and were cleared from the lungs to the same extent. CONCLUSIONS: We show that different NPs variably adsorb proteins from the lung lining fluid. The amount of albumin in the NP corona varies as does NP uptake by AMs. However, albumin coating does not affect the translocation of gold NPs across the air-blood barrier. A more extensive database of corona composition of a diverse NP library will develop a platform to help predict the effects and biokinetics of inhaled NPs.

3D topographies promote macrophage M2d-Subset differentiation.

In vitro cellular models denote a crucial part of drug discovery programs as they aid in identifying successful drug candidates based on their initial efficacy and potency. While tremendous headway has been achieved in improving 2D and 3D culture techniques, there is still a need for physiologically relevant systems that can mimic or alter cellular responses without the addition of external biochemical stimuli. A way forward to alter cellular responses is using physical cues, like 3D topographical inorganic substrates, to differentiate macrophage-like cells. Herein, protein secretion and gene expression markers for various macrophage subsets cultivated on a 3D topographical substrate are investigated. The results show that macrophages differentiate into anti-inflammatory M2-type macrophages, secreting increased IL-10 levels compared to the controls. Remarkably, these macrophage cells are differentiated into the M2d subset, making up the main component of tumour-associated macrophages (TAMs), as measured by upregulated Il-10 and Vegf mRNA. M2d subset differentiation is attributed to the topographical substrates with 3D fractal-like geometries arrayed over the surface, else primarily achieved by tumour-associated factors in vivo. From a broad perspective, this work paves the way for implementing 3D topographical inorganic surfaces for drug discovery programs, harnessing the advantages of in vitro assays without external stimulation and allowing the rapid characterisation of therapeutic modalities in physiologically relevant environments.

Poly-L-lysine-coated silver nanoparticles as positively charged substrates for surface-enhanced Raman scattering.

Positively charged nanoparticles to be used as substrates for surface-enhanced Raman scattering (SERS) were prepared by coating citrate-reduced silver nanoparticles with the cationic polymer poly-l-lysine. The average diameter of the coated nanoparticles is 75 nm, and their zeta potential is +62.3 ± 1.7 mV. UV-vis spectrophotometry and dynamic light scattering measurements show that no aggregation occurs during the coating process. As an example of their application, the so-obtained positively charged coated particles were employed to detect nanomolar concentrations of the anionic chromophore bilirubin using SERS. Because of their opposite charge, bilirubin molecules interact with the coated nanoparticles, allowing SERS detection. The SERS intensity increases linearly with concentration in a range from 10 to 200 nM, allowing quantitative analysis of bilirubin aqueous solutions.

Nanomedicine for treatment of diabetes in an aging population: state-of-the-art and future developments.

Nowadays diabetes, especially type 2 diabetes (which is strongly related to the Western diet and life-style), has developed worldwide into an epidemic disease. Nanomedicine aims to provide novel tools for diagnosis, therapy and point-of-care management of patients. Several nanotechnological approaches were developed to improve life quality for patients with insulin-dependent diabetes. They facilitate blood glucose management by non-invasive glucose measurement as well as insulin administration mainly by delivering the fragile protein as protected and targeted formulation via nasal or oral route. In the present review the oral or nasal insulin delivery by polymeric nanoparticles is discussed with focus on physiological change either related to the disease, diabetes or age-related metabolic variations influencing insulin release and bioavailability. One critical point is that new generations of targeted nanoparticle based drugs are developed and optimized for certain metabolic conditions. These conditions may change with age or disease. The influence of age-related factors such as immaturity in very young age, metabolic and physiologic changes in old age or insufficient animal models are still under-investigated not only in nanomedicine but also generally in pharmacology. Summarizing it can be noted that the bioavailability of insulin administered via routes others than subcutaneously is comparably low (max. 60%). Moreover factors like changed gut permeability as described for diabetes type 1 or other metabolic peculiarities such as insulin resistance in case of type 2 diabetes also play a role in affecting the development of novel nanoparticulated drug preparations and can be responsible for unsuccessful translation of promising animal results into human therapy. In future insulin nanoparticle development for diabetes must consider not only requirements imposed by the drug but also metabolic changes inflicted by disease or by age. Moreover new approaches are required for prevention of the disease.

The Fast Track for Intestinal Tumor Cell Differentiation and In Vitro Intestinal Models by Inorganic Topographic Surfaces.

Three-dimensional (3D) complex in vitro cell systems are well suited to providing meaningful and translatable results in drug screening, toxicity measurements, and biological studies. Reliable complex gastrointestinal in vitro models as a testbed for oral drug administration and toxicity are very valuable in achieving predictive results for clinical trials and reducing animal testing. However, producing these models is time-consuming due to the lengthy differentiation of HT29 or other cells into mucus-producing goblet cells or other intestinal cell lineages. In the present work, HT29 cells were grown on an inorganic topographic surface decorated with a periodic pattern of micrometre-sized amorphous SiO2 structures for up to 35 days. HT29 cells on topographic surfaces were compared to undifferentiated HT29 in glucose-containing medium on glass or culture dish and with HT29 cells differentiated for 30 days in the presence of methotrexate (HT29-MTX). The cells were stained with Alcian blue for mucus, antibodies for mucus 2 (goblet cells), villin (enterocytes), lysozyme (Paneth cells), and FITC-labeled lectins to identify different cells, glycomic profiles, and cell features. We observed that HT29 cells on topographic surfaces showed more similarities with the differentiated HT29-MTX than with undifferentiated HT29. They formed islands of cell clusters, as observed for HT29-MTX. Already after 2 days, the first mucus secretion was shown by Alcian blue stain and FITC-wheat germ agglutinin. After 4-6 days, mucus was observed on the cell surface and in the intercellular space. The cell layer was undulated, and in 3D reconstruction, the cells showed a clear polarisation with a strong actin signal to one membrane. The lectins and the antibody-staining confirmed the heterogeneous composition of differentiated HT29 cells on topographic surfaces after 6-8 days, or after 6-8 days following MTX differentiation (30 days).

Complex Tumor Spheroid Formation and One-Step Cancer-Associated Fibroblasts Purification from Hepatocellular Carcinoma Tissue Promoted by Inorganic Surface Topography.

In vitro cell models play important roles as testbeds for toxicity studies, drug development, or as replacements in animal experiments. In particular, complex tumor models such as hepatocellular carcinoma (HCC) are needed to predict drug efficacy and facilitate translation into clinical practice. In this work, topographical features of amorphous silicon dioxide (SiO2) are fabricated and tested for cell culture of primary HCC cells and cell lines. The topographies vary from pyramids to octahedrons to structures named fractals, with increased hierarchy and organized in periodic arrays (square or Hexagonal). The pyramids were found to promote complex 2D/3D tissue formation from primary HCC cells. It was found that the 2D layer was mainly composed of cancer-associated fibroblasts (CAFs), while the 3D spheroids were composed of tumor cells enwrapped by a CAF layer. Compared with conventional protocols for 3D cultures, this novel approach mimics the 2D/3D complexity of the original tumor by invading CAFs and a microtumor. Topographies such as octahedrons and fractals exclude tumor cells and allow one-step isolation of CAFs even directly from tumor tissue of patients as the CAFs migrate into the structured substrate. Cell lines form spheroids within a short time. The presented inorganic topographical surfaces stimulate complex spheroid formation while avoiding additional biological scaffolds and allowing direct visualization on the substrate.

Polyphenols Epigallocatechin Gallate and Resveratrol, and Polyphenol-Functionalized Nanoparticles Prevent Enterovirus Infection through Clustering and Stabilization of the Viruses.

To efficiently lower virus infectivity and combat virus epidemics or pandemics, it is important to discover broadly acting antivirals. Here, we investigated two naturally occurring polyphenols, Epigallocatechin gallate (EGCG) and Resveratrol (RES), and polyphenol-functionalized nanoparticles for their antiviral efficacy. Concentrations in the low micromolar range permanently inhibited the infectivity of high doses of enteroviruses (107 PFU/mL). Sucrose gradient separation of radiolabeled viruses, dynamic light scattering, transmission electron microscopic imaging and an in-house developed real-time fluorescence assay revealed that polyphenols prevented infection mainly through clustering of the virions into very stable assemblies. Clustering and stabilization were not compromised even in dilute virus solutions or after diluting the polyphenols-clustered virions by 50-fold. In addition, the polyphenols lowered virus binding on cells. In silico docking experiments of these molecules against 2- and 3-fold symmetry axes of the capsid, using an algorithm developed for this study, discovered five binding sites for polyphenols, out of which three were novel binding sites. Our results altogether suggest that polyphenols exert their antiviral effect through binding to multiple sites on the virion surface, leading to aggregation of the virions and preventing RNA release and reducing cell surface binding.

Reproducibility warning: The curious case of polyethylene glycol 6000 and spheroid cell culture.

Reproducibility of results is essential for a well-designed and conducted experiment. Several reasons may originate failure in reproducing data, such as selective reporting, low statistical power, or poor analysis. In this study, we used PEG6000 samples from different distributors and tested their capability inducing spheroid formation upon surface coating. MALDI-MS, NMR, FTIR, and Triple SEC analysis of the different PEG60000s showed nearly identical physicochemical properties different, with only minor differences in mass and hydrodynamic radius, and AFM analysis showed no significant differences in the surface coatings obtained with the available PEG6000s. Despite these similarities, just one showed a highly reproducible formation of spheroids with different cell lines, such as HT-29, HeLa, Caco2, and PANC-1. Using the peculiar PEG6000 sample and a reference PEG6000 chosen amongst the others as control, we tested the effect of the cell/PEG interaction by incubating cells in the PEG solution prior to cell plating. These experiments indicate that the spheroid formation is due to direct interaction of the polymer with the cells rather than by interaction of cells with the coated surfaces. The experiments point out that for biological entities, such as cells or tissues, even very small differences in impurities or minimal variations in the starting product can have a very strong impact on the reproducibility of data.

Multi-sulfonated ligands on gold nanoparticles as virucidal antiviral for Dengue virus.

Dengue virus (DENV) causes 390 million infections per year. Infections can be asymptomatic or range from mild fever to severe haemorrhagic fever and shock syndrome. Currently, no effective antivirals or safe universal vaccine is available. In the present work we tested different gold nanoparticles (AuNP) coated with ligands ω-terminated with sugars bearing multiple sulfonate groups. We aimed to identify compounds with antiviral properties due to irreversible (virucidal) rather than reversible (virustatic) inhibition. The ligands varied in length, in number of sulfonated groups as well as their spatial orientation induced by the sugar head groups. We identified two candidates, a glucose- and a lactose-based ligand showing a low EC50 (effective concentration that inhibit 50% of the viral activity) for DENV-2 inhibition, moderate toxicity and a virucidal effect in hepatocytes with titre reduction of Median Tissue Culture Infectious Dose log10TCID50 2.5 and 3.1. Molecular docking simulations complemented the experimental findings suggesting a molecular rationale behind the binding between sulfonated head groups and DENV-2 envelope protein.

Validation of Hepatocellular Carcinoma Experimental Models for TGF-ß Promoting Tumor Progression.

Transforming growth factor beta (TGF-ß) is a pleiotropic cytokine with dual role in hepatocellular carcinoma (HCC). It acts as tumor-suppressor and tumor-promoter in the early and late stage respectively. TGF-ß influences the tumor-stroma cross-talk affecting the tumoral microenvironment. Therefore, inhibiting the TGF- ß mediated pathway alone and/or in combination with chemotherapeutics represents an important therapeutic option. Experimental models to dissect the role of TGF-ß in HCC tumor progression as well as the effectiveness of specific inhibitors are tricky. HCC cell lines respond to TGF-ß according to their epithelial phenotype. However, the mesenchymal and more aggressive HCC cell lines in vitro, do not develop tumors when transplanted in vivo, thus hampering the understanding of molecular pathways that dictate outcome. In addition, in this model the native immune system is abolished, therefore the contribution of inflammation in hepatocarcinogenesis is unreliable. Different strategies have been set up to engineer HCC animal models, including genetically modified mice, chemically induced HCC, or hydrodynamic techniques. Patient-derived xenograft is currently probably the most fascinating model, keeping in mind that models cannot mirror all the reality. In this context, we discuss the different available HCC mouse models including our experimental model treated with inhibitor of TGF-ß receptor Type I kinase (Galunisertib) and a potential role of exosomes in TGF-ß moderated tumor progression of HCC. Unfortunately, no positive results were obtained in our treated orthotopic model because it does not reproduce the critical tumor-stroma interactions of the HCC.

Urinary exosomal shuttle RNA: Promising cancer diagnosis biomarkers of lower urinary tract.

BACKGROUND: Prostate and bladder cancers continue to be the first and fourth most common cancers in men worldwide; thus there is an urgent need for more accurate biomarkers that can detect these types of cancer in a non-invasive way. Liquid biopsy is a new non-invasive tool for diagnosis and with a virtually unlimited supply urine is even more attractive resource since urinary exosomes have been discovered to contain RNAs that are hallmarks of cancer. It is challenging to assay those secreting lower amounts of molecules. METHODS: This review, based on articles identified through a PubMed/MEDLINE search, comprehensively summarizes state of the art approaches used in the discovery and validation of exosomal RNA biomarkers purified from the urine for lower urinary tract cancer. RESULTS: The combination of PCA3 and ERG has shown a relatively good improvement in diagnostic performance; examples of other potential biomarkers and the methods utilized in their discovery are also discussed in this review. CONCLUSIONS: Of these last markers, to date there are still few data to implement these for routine diagnosis.

Patchy Amphiphilic Dendrimers Bind Adenovirus and Control Its Host Interactions and in Vivo Distribution.

The surface of proteins is heterogeneous with sophisticated but precise hydrophobic and hydrophilic patches, which is essential for their diverse biological functions. To emulate such distinct surface patterns on macromolecules, we used rigid spherical synthetic dendrimers (polyphenylene dendrimers) to provide controlled amphiphilic surface patches with molecular precision. We identified an optimal spatial arrangement of these patches on certain dendrimers that enabled their interaction with human adenovirus 5 (Ad5). Patchy dendrimers bound to the surface of Ad5 formed a synthetic polymer corona that greatly altered various host interactions of Ad5 as well as in vivo distribution. The dendrimer corona (1) improved the ability of Ad5-derived gene transfer vectors to transduce cells deficient for the primary Ad5 cell membrane receptor and (2) modulated the binding of Ad5 to blood coagulation factor X, one of the most critical virus-host interactions in the bloodstream. It significantly enhanced the transduction efficiency of Ad5 while also protecting it from neutralization by natural antibodies and the complement system in human whole blood. Ad5 with a synthetic dendrimer corona revealed profoundly altered in vivo distribution, improved transduction of heart, and dampened vector sequestration by liver and spleen. We propose the design of bioactive polymers that bind protein surfaces solely based on their amphiphilic surface patches and protect against a naturally occurring protein corona, which is highly attractive to improve Ad5-based in vivo gene therapy applications.