La capsazepina antagoniza la activación de TRPV1 inducida por estímulos térmicos y osmóticos en células humanas similares a odontoblastos

Objetivos: El dolor dental, que es el principal motivo de consulta de los pacientes al dentista, está clasificado como un problema de salud pública. El estudio de los mecanismos celulares y moleculares que contribuyen al dolor es un elemento fundamental para desarrollar nuevos analgésicos. Mediante el uso de un antagonista selectivo en un modelo in vitro, este estudio pretendía establecer el papel del TRPV-1 en células humanas similares a odontoblastos (OLC) como diana terapéutica para el dolor dental mediado por estímulos térmicos y osmóticos nocivos. Métodos: Las OLC se diferenciaron a partir de células mesenquimales de la pulpa dental y se evaluó la expresión de TRPV1. La activación de TRPV-1 se determinó evaluando los cambios en la concentración de calcio tras la estimulación con soluciones hiperosmóticas de manitol y xilitol o DMEM calentado a 45 °C, utilizando la sonda fluorescente de calcio Fluo-4 AM. Además, los cambios en la fluorescencia (F/F0) debidos al flujo de calcio se evaluaron mediante fluorometría y citometría de flujo. Simultáneamente, las células fueron coestimuladas con el antagonista selectivo capsazepina (CZP). Resultados: Las OLC expresaron DSPP y DMP-1, confirmando su fenotipo celular. Se expresó TRPV1, y su activación por diferentes estímulos produjo un aumento del Ca2+ citosólico que fue reducido por el antagonista. Los dos métodos utilizados para evaluar la activación del TRPV1 mediante la medición de la fluorescencia de la sonda de calcio mostraron patrones similares. Conclusiones: Estos resultados sugieren que la modulación del TRPV-1 mediante un antagonista puede implementarse como estrategia farmacológica para el manejo del dolor dental mediado por estímulos hiperosmóticos y térmicos.Objectives: Dental pain, which is the main reason for patients consulting dentists, is classified as a public health concern. The study of cellular and molecular mechanisms contributing to pain is a fundamental element for developing new analgesics. By using a selective antagonist in an in vitro model, this study aimed to establish the role of TRPV-1 in human odontoblast-like cells (OLCs) as a therapeutic target for dental pain mediated by noxious thermal and osmotic stimuli. Methods: OLCs were differentiated from dental pulp mesenchymal cells and TRPV1 expression was evaluated. Activation of TRPV-1 was determined by evaluating changes in calcium concentration after stimulation with mannitol and xylitol hyperosmotic solutions or DMEM heated at 45 °C, using the fluorescent calcium probe Fluo-4 AM. In addition, changes in fluorescence (F/F0) due to calcium flux were evaluated using fluorometry and flow cytometry. Simultaneously, the cells were co-stimulated with the selective antagonist capsazepine (CZP). Results: OLCs expressed DSPP and DMP-1, confirming their cellular phenotype. TRPV1 was expressed, and its activation by different stimuli produced an increase in cytosolic Ca2+ which was reduced by the antagonist. Both methods used to evaluate TRPV1 activation through the measurement of calcium probe fluorescence showed similar patterns. Conclusions: These results suggest that TRPV-1 modulation using an antagonist can be implemented as a pharmacological strategy for managing dental pain mediated by hyperosmotic and thermal stimuli

Odontoblast-Like Cells Differentiated from Dental Pulp Stem Cells Retain Their Phenotype after Subcultivation

Odontoblasts, the main cell type in teeth pulp tissue, are not cultivable and they are responsible for the first line of response after dental restauration. Studies on dental materials cytotoxicity and odontoblast cells physiology require large quantity of homogenous cells retaining most of the phenotype characteristics. Odontoblast-like cells (OLC) were differentiated from human dental pulp stem cells using differentiation medium (containing TGF-β1), and OLC expanded after trypsinization (EXP-21) were evaluated and compared. Despite a slower cell growth curve, EXP-21 cells express similarly the odontoblast markers dentinal sialophosphoprotein and dentin matrix protein-1 concomitantly with RUNX2 transcripts and low alkaline phosphatase activity as expected. Both OLC and EXP-21 cells showed similar mineral deposition activity evidenced by alizarin red and von Kossa staining. These results pointed out minor changes in phenotype of subcultured EXP-21 regarding the primarily differentiated OLC, making the subcultivation of these cells a useful strategy to obtain odontoblasts for biocompatibility or cell physiology studies in dentistry

Magnetoliposomas multifuncionales como vehículos de administración de fármacos para el tratamiento potencial de la enfermedad de Parkinson

La enfermedad de Parkinson (EP) es el segundo trastorno neurodegenerativo más frecuente después de la enfermedad de Alzheimer. Por ello, el desarrollo de nuevas tecnologías y estrategias para tratarla es una prioridad sanitaria mundial. Los tratamientos actuales incluyen la administración de levodopa, inhibidores de la monoaminooxidasa, inhibidores de la catecol-O-metiltransferasa y fármacos anticolinérgicos. Sin embargo, la liberación efectiva de estas moléculas, debido a la limitada biodisponibilidad, es un reto importante para el tratamiento de la EP. Como estrategia para resolver este desafío, en este estudio desarrollamos un novedoso sistema de liberación de fármacos multifuncional magnético y sensible a estímulos redox, basado en nanopartículas de magnetita funcionalizadas con la proteína translocadora de alto rendimiento OmpA y encapsuladas en liposomas de lecitina de soja. Los magnetoliposomas multifuncionales (MLP) obtenidos se ensayaron en neuroblastoma, glioblastoma, astrocitos primarios humanos y de rata, células endoteliales de rata de barrera hematoencefálica, células endoteliales microvasculares primarias de ratón y en un modelo celular inducido por EP. Los MLP demostraron un excelente rendimiento en ensayos de biocompatibilidad, incluyendo hemocompatibilidad (porcentajes de hemólisis por debajo del 1%), agregación plaquetaria, citocompatibilidad (viabilidad celular por encima del 80% en todas las líneas celulares probadas), potencial de membrana mitocondrial (alteraciones no observadas) y producción intracelular de ROS (impacto insignificante en comparación con los controles). Además, las nanovehículas mostraron una aceptable internalización celular (área cubierta cercana al 100% a los 30 min y a las 4 h) y capacidad de escape endosomal (disminución significativa de la colocalización lisosomal tras 4 h de exposición). Además, se emplearon simulaciones de dinámica molecular para comprender mejor el mecanismo de translocación subyacente de la proteína OmpA, mostrando hallazgos clave relativos a interacciones específicas con fosfolípidos. En general, la versatilidad y el notable rendimiento in vitro de este novedoso nanovehículo lo convierten en una tecnología de administración de fármacos adecuada y prometedora para el tratamiento potencial de la EP.Parkinson’s disease (PD) is the second most common neurodegenerative disorder after Alzheimer’s disease. Therefore, development of novel technologies and strategies to treat PD is a global health priority. Current treatments include administration of Levodopa, monoamine oxidase inhibitors, catechol-O-methyltransferase inhibitors, and anticholinergic drugs. However, the effective release of these molecules, due to the limited bioavailability, is a major challenge for the treatment of PD. As a strategy to solve this challenge, in this study we developed a novel multifunctional magnetic and redox-stimuli responsive drug delivery system, based on the magnetite nanoparticles functionalized with the high-performance translocating protein OmpA and encapsulated into soy lecithin liposomes. The obtained multifunctional magnetoliposomes (MLPs) were tested in neuroblastoma, glioblastoma, primary human and rat astrocytes, blood brain barrier rat endothelial cells, primary mouse microvascular endothelial cells, and in a PD-induced cellular model. MLPs demonstrated excellent performance in biocompatibility assays, including hemocompatibility (hemolysis percentages below 1%), platelet aggregation, cytocompatibility (cell viability above 80% in all tested cell lines), mitochondrial membrane potential (non-observed alterations) and intracellular ROS production (negligible impact compared to controls). Additionally, the nanovehicles showed acceptable cell internalization (covered area close to 100% at 30 min and 4 h) and endosomal escape abilities (significant decrease in lysosomal colocalization after 4 h of exposure). Moreover, molecular dynamics simulations were employed to better understand the underlying translocating mechanism of the OmpA protein, showing key findings regarding specific interactions with phospholipids. Overall, the versatility and the notable in vitro performance of this novel nanovehicle make it a suitable and promising drug delivery technology for the potential treatment of PD

In Vitro Infection with Dengue Virus Induces Changes in the Structure and Function of the Mouse Brain Endothelium.

BACKGROUND:The neurological manifestations of dengue disease are occurring with greater frequency, and currently, no information is available regarding the reasons for this phenomenon. Some viruses infect and/or alter the function of endothelial organs, which results in changes in cellular function, including permeability of the blood-brain barrier (BBB), which allows the entry of infected cells or free viral particles into the nervous system. METHODS:In the present study, we standardized two in vitro models, a polarized monolayer of mouse brain endothelial cells (MBECs) and an organized co-culture containing MBECs and astrocytes. Using these cell models, we assessed whether DENV-4 or the neuro-adapted dengue virus (D4MB-6) variant infects cells or induces changes in the structure or function of the endothelial barrier. RESULTS:The results showed that MBECs, but not astrocytes, were susceptible to infection with both viruses, although the percentage of infected cells was higher when the neuro-adapted virus variant was used. In both culture systems, DENV infection changed the localization of the tight junction proteins Zonula occludens (ZO-1) and Claudin-1 (Cln1), and this process was associated with a decrease in transendothelial resistance, an increase in macromolecule permeability and an increase in the paracellular passing of free virus particles. MBEC infection led to transcriptional up-regulation of adhesion molecules (VCAM-1 and PECAM) and immune mediators (MCP-1 and TNF- α) that are associated with immune cell transmigration, mainly in D4MB-6-infected cells. CONCLUSION:These results indicate that DENV infection in MBECs altered the structure and function of the BBB and activated the endothelium, affecting its transcellular and paracellular permeability and favoring the passage of viruses and the transmigration of immune cells. This phenomenon can be harnessed for neurotropic and neurovirulent strains to infect and induce alterations in the CNS

Endothelial Dysfunction, HMGB1, and Dengue: An Enigma to Solve

Dengue is a viral infection caused by dengue virus (DENV), which has a significant impact on public health worldwide. Although most infections are asymptomatic, a series of severe clinical manifestations such as hemorrhage and plasma leakage can occur during the severe presentation of the disease. This suggests that the virus or host immune response may affect the protective function of endothelial barriers, ultimately being considered the most relevant event in severe and fatal dengue pathogenesis. The mechanisms that induce these alterations are diverse. It has been suggested that the high mobility group box 1 protein (HMGB1) may be involved in endothelial dysfunction. This non-histone nuclear protein has different immunomodulatory activities and belongs to the alarmin group. High concentrations of HMGB1 have been detected in patients with several infectious diseases, including dengue, and it could be considered as a biomarker for the early diagnosis of dengue and a predictor of complications of the disease. This review summarizes the main features of dengue infection and describes the known causes associated with endothelial dysfunction, highlighting the involvement and possible relationship between HMGB1 and DENV

Virus titration in the upper and lower chambers in the co-culture model.

<p>Virus titration in the upper and lower chambers in the co-culture model.</p

MBEC susceptibility to DENV infection.

<p><b>(A)</b>. MBEC cultured on glass coverslips were inoculated for 48 h with mock suspension or infected with DENV-4 or D4MB-6 at an MOI:1 and stained for detecting viral envelope protein (red) and ZO-1 protein (green). Both viruses infected the MBECs and showed perinuclear localization of viral E protein (arrow). On the other hand, the typical plasma membrane localization pattern of ZO-1 was detected in the mock and DENV-4 infected cultures, while in the D4MB-6 infected cells was located mainly in the cytoplasm, in clusters or in a discontinuous pattern in the perimembrane region. Bar = 20 μm. (<b>B).</b> Infection percentages of MBEC after 24 or 48 h p.i. Infection proportion was significantly higher with D4MB-6 at 48 h p.i. (49%), with regard to 11% of the cells infected with DENV-4. Data are shown as the mean +/- SD of 3 independent cultures performed by duplicate.</p

Scheme barrier models and evaluation of TEER and permeability assay in each models.

<p><b>(A).</b> Endothelial barrier model scheme. Transwell inserts were used to establish the two barrier models. The first one (Monolayer model) consisted in MBEC cultured on the luminal side of the membrane (upper side) for four days until monolayer reaches TEER values between 1 to 1,5 kΩ. For establishing the second one barrier model (co-culture model), the glial cells were seed on the abluminal side inverting the insert for three days, then it was flipped to the right position before seeding the MBEC in the luminal side. (<b>B).</b> Transendothelial electrical resistance. MBEC in each barrier model were infected or treated with mock inoculum. Since 10 h p.i. there was a significant reduction in TEER in DENV-4 and D4MB-6 infected compared with mock-inoculated barrier models. This TEER loss was sustained up to 48 h p.i. (p<0.05, Kruskal-Wallis and Bonferroni tests), however, TEER changes were less drastic in MBEC-astrocytes co-culture with regard to monolayer barrier model. (<b>C)</b>. Permeability assay. Using the same culture and infection protocols described above, dextran blue (DB) permeability assays were performed. DB was added in the insert’s upper chamber and at each time point; the lower chamber medium culture was collected to quantify the DB pass through by spectrophotometry. Since 10 to 48 h p.i. the infection with both virus strains induced a significant increase in lower chamber DB concentration coinciding with TEER loss. Barrier damage and DB quantified in the lower medium of MBEC-astrocytes co-culture were too low (between 0,2 to 1,2%) indicating a protective role of astrocytes. Data shown are mean of TEER or DB percentage from triplicates of two independent cultures and SD.</p

DENV transmigration model of passage through the BBB.

<p><b>(A).</b> After the virus inoculation, MBECs are activated and/or infected, inducing early TJP relocalization and the expression of MCP-1 and adhesion molecules (10 h p.i.). These changes allowed viral paracellular transport by which the particles passed through to abluminal side. Adhesion molecule expression also changed, bringing immune cells closer and favor rolling. (<b>B).</b> After viral replication in MBEC, transcellular virus transport occurs, and the integrity of the barrier is damaged, resulting in an increase in virus paracellular transport to the abluminal side. MBEC activation and the production of inflammatory mediators promote leukocyte adhesion and transmigration, which carries the virus through via a Trojan horse mechanism.</p