Circulating extracellular vesicles as potential biomarkers in chronic fatigue syndrome/myalgic encephalomyelitis: an exploratory pilot study

Chronic Fatigue Syndrome (CFS), also known as Myalgic Encephalomyelitis (ME) is an acquired, complex and multisystem condition of unknown etiology, no established diagnostic lab tests and no universally FDA-approved drugs for treatment. CFS/ME is characterised by unexplicable disabling fatigue and is often also associated with numerous core symptoms. A growing body of evidence suggests that extracellular vesicles (EVs) play a role in cell-to-cell communication, and are involved in both physiological and pathological processes. To date, no data on EV biology in CFS/ME are as yet available. The aim of this study was to isolate and characterise blood-derived EVs in CFS/ME. Blood samples were collected from 10 Spanish CFS/ME patients and 5 matched healthy controls (HCs), and EVs were isolated from the serum using a polymer-based method. Their protein cargo, size distribution and concentration were measured by Western blot and nanoparticle tracking analysis. Furthermore, EVs were detected using a lateral flow immunoassay based on biomarkers CD9 and CD63. We found that the amount of EV-enriched fraction was significantly higher in CFS/ME subjects than in HCs (p = 0.007) and that EVs were significantly smaller in CFS/ME patients (p = 0.014). Circulating EVs could be an emerging tool for biomedical research in CFS/ME. These findings provide preliminary evidence that blood-derived EVs may distinguish CFS/ME patients from HCs. This will allow offer new opportunities and also may open a new door to identifying novel potential biomarkers and therapeutic approaches for the condition

Carbon-Coated Superparamagnetic Nanoflowers for Biosensors Based on Lateral Flow Immunoassays

Superparamagnetic iron oxide nanoflowers coated by a black carbon layer (Fe3O4@C) were studied as labels in lateral flow immunoassays. They were synthesized by a one-pot solvothermal route, and they were characterized (size, morphology, chemical composition, and magnetic properties). They consist of several superparamagnetic cores embedded in a carbon coating holding carboxylic groups adequate for bioconjugation. Their multi-core structure is especially efficient for magnetic separation while keeping suitable magnetic properties and appropriate size for immunoassay reporters. Their functionality was tested with a model system based on the biotin–neutravidin interaction. For this, the nanoparticles were conjugated to neutravidin using the carbodiimide chemistry, and the lateral flow immunoassay was carried out with a biotin test line. Quantification was achieved with both an inductive magnetic sensor and a reflectance reader. In order to further investigate the quantifying capacity of the Fe3O4@C nanoflowers, the magnetic lateral flow immunoassay was tested as a detection system for extracellular vesicles (EVs), a novel source of biomarkers with interest for liquid biopsy. A clear correlation between the extracellular vesicle concentration and the signal proved the potential of the nanoflowers as quantifying labels. The limit of detection in a rapid test for EVs was lower than the values reported before for other magnetic nanoparticle labels in the working range 0–3 × 107 EVs/μL. The method showed a reproducibility (RSD) of 3% (n = 3). The lateral flow immunoassay (LFIA) rapid test developed in this work yielded to satisfactory results for EVs quantification by using a precipitation kit and also directly in plasma samples. Besides, these Fe3O4@C nanoparticles are easy to concentrate by means of a magnet, and this feature makes them promising candidates to further reduce the limit of detectionThis work was supported in part by Spanish Ministry of Economy and Competitiveness under projects MAT2017-84959-C2-1-R and the Principality of Asturias (Spain) under project IDI/2018/000185 and the Consellería de Educación Program for Development of a Strategic Grouping in Materials (AEMAT) at the University of Santiago de Compostela under Grant No. ED431E208/08, Xunta de Galicia. Amanda Moyano was supported by a “Severo Ochoa” fellowship (Consejería de Educación y Cultura del Gobierno del Principado de Asturias, grant BP17-152)S

Microparticles in multiple sclerosis and clinically isolated syndrome: effect on endothelial barrier function.

Background Cell-derived microparticles are secreted in response to cell damage or dysfunction. Endothelial and platelet dysfunction are thought to contribute to the development of multiple sclerosis (MS). Our aim here is, first, to compare the presence of microparticles of endothelial and platelet origin in plasma from patients with different clinical forms of MS and with clinically isolated syndrome. Second, to investigate the effect of microparticles on endothelial barrier function. Results Platelet-poor plasma from 95 patients (12 with clinically isolated syndrome, 51 relapsing-remitting, 23 secondary progressive, 9 primary progressive) and 49 healthy controls were analyzed for the presence of platelet-derived and endothelium-derived microparticles by flow cytometry. The plasma concentration of platelet-derived and endothelium-derived microparticles increased in all clinical forms of MS and in clinically isolated syndrome versus controls. The response of endothelial barriers to purified microparticles was measured by electric cell-substrate impedance sensing. Microparticles from relapsing-remitting MS patients induced, at equivalent concentrations, a stronger disruption of endothelial barriers than those from healthy donors or from patients with clinically isolated syndrome. MS microparticles acted synergistically with the inflammatory mediator thrombin to disrupt the endothelial barrier function. Conclusions Plasma microparticles should be considered not only as markers of early stages of MS, but also as pathological factors with the potential to increase endothelial permeability and leukocyte infiltration

Structural studies of proteins involved in spinal muscular atrophy (SMA): Sam68 and its interaction with RNA

Spinal muscular atrophy (SMA) is an autosomal recessive, and neurodegenerative disease, most of the cases caused by mutations in the SMN1 gene. The expression levels of the homologue gene, SMN2, do not compensate the activity of the SMN protein. A number of studies have described that the instability of the SMN2 gene is due to a C-T transition in exon 7, which causes that the majority of SMN2 transcripts are alternatively spliced, excluding exon 7. Sam68 is a member of the STAR family of proteins (signal transduction and activation of RNA), which regulates the alternative splicing of several genes involved in the neurogenesis. Inhibition of Sam68's activity can rescue SMN activity, suggesting an important role of this protein in the disease. The development of short interfering peptides / molecules to modulate the alternative splicing of the SMN2 gene may be effective and improve the motor function. This approach requires the resolution of the 3D-structure of Sam68, as well as the modeling of the protein-RNA interaction. In this project, structural studies Sam68 have been carried out by using different computational tools for protein structure prediction, as well as for prediction of RNA-protein interactions. The scores obtained were greater in the area corresponding to the KH domain (RNA-binding domain), although the reliability prediction of RNA-interacting residues was more limited due to the lack of experimental research available in the databases.La atrofia muscular espinal es una enfermedad neurodegenerativa autosómica recesiva, causada en la mayor parte de los casos por mutaciones en el gen SMN1. Los niveles de expresión del gen homólogo, SMN2, no compensan la actividad de la proteína SMN. Algunos estudios han descrito que la inestabilidad del gen SMN2 se debe a una transición C-T en el exón 7, lo cual produce que la mayoría de los tránscritos de SMN2 se produzcan por empalme alternativo, excluyendo el exón 7. Sam68 pertenece a la familia de proteínas STAR (transducción de señales y activación del ARN), la cual regula el proceso de empalme alternativo en varios genes implicados en la neurogénesis. La inhibición de la actividad de Sam68 puede rescatar la actividad de SMN, lo que sugiere que esta proteína juega un papel importante en esta enfermedad. El desarrollo de péptidos pequeños / moléculas interferentes para modular el empalme alternativo del gen SMN2 puede ser efectivo y mejorar la actividad motora. Este enfoque requiere resolver la estructura 3D de Sam68, así como el modelado de la interacción ARN-proteína. En este proyecto se han llevado a cabo estudios estructurales mediante el uso de diversas herramientas computacionales para la predicción de estructura de Sam68, así como para la predicción de interacciones ARN-proteína. Las puntuaciones obtenidas fueron más altas en la región correspondiente al dominio KH (dominio de unión al ARN), aunque la fiabilidad de la predicción de los residuos que interaccionan con el ARN es más limitada debido a la falta de estudios experimentales disponibles en las bases de datos.L'atròfia muscular espinal és una malaltia neurodegenerativa autosómica recessiva, causada en la major part dels casos per mutacions en el gen SMN1. Els nivells d'expressió del gen homòleg, SMN2, no compensen l'activitat de la proteïna SMN. Alguns estudis han descrit que la inestabilitat del gen SMN2 es deu a una transició C-T en el exón 7, la qual cosa produeix que la majoria dels tránscritos de SMN2 es produeixin per entroncament alternatiu, excloent el exón 7. Sam68 pertany a la família de proteïnes STAR (transducción de senyals i activació del ARN), la qual regula el procés d'entroncament alternatiu en diversos gens implicats en la neurogénesis. La inhibició de l'activitat de Sam68 pot rescatar l'activitat de SMN, la qual cosa suggereix que aquesta proteïna juga un paper important en aquesta malaltia. El desenvolupament de pèptids petits / molècules interferents per modular l'entroncament alternatiu del gen SMN2 pot ser efectiu i millorar l'activitat motora. Aquest enfocament requereix resoldre l'estructura 3D de Sam68, així com el modelatge de la interacció ARN-proteïna. En aquest projecte s'han dut a terme estudis estructurals mitjançant l'ús de diverses eines computacionals per a la predicció d'estructura de Sam68, així com per a la predicció d'interaccions ARN-proteïna. Les puntuacions obtingudes van ser més altes a la regió corresponent al domini KH (domini d'unió al ARN), encara que la fiabilitat de la predicció dels residus que interaccionen amb el ARN és més limitada a causa de la falta d'estudis experimentals disponibles en les bases de dades

Extracellular vesicles: From biology to biomedical applications

Legend says that Philippides ran to Athens to announce the victory against the Persians in the Battle of Marathon [...

Unusual gold nanoparticle-antibody interactions

The formation of an antibody (Ab) protein corona surrounding gold nanoparticles (AuNPs) is a crucial step in the design of immunological assays. The Ab corona stabilizes AuNPs, preventing their aggregation even at high ionic strength, and can be achieved by simply mixing Abs and AuNPs. In this paper, we report the unusual interactions between AuNPs and the antibody against L1 Cell Adhesion Molecule (L1CAM) purified from rabbits.We have observed that at low ionic strength, the addition of a wide range of concentrations of rabbit monoclonal Abs against L1CAM protein immediately causes the coagulation of citrate-capped gold nanoparticles. This finding is surprising since the addition of proteins to colloidal gold usually forms a stable protein corona. The combination of extinction spectra, dynamic light scattering (DLS), and transmission electron microscopy (TEM) measurements reveals the presence of small clusters of AuNPs coated by the antibodies, as well as micron-sized antibody aggregates. Furthermore, static light scattering measurements demonstrate that Ab self-interactions are attractive (with a negative second virial coefficient, B2) and induce very slow Ab self-aggregation over several months. Overall, these results indicate that, at low ionic strength, the presence of AuNPs enhances Ab-Ab interactions, leading to their rapid aggregation. Simultaneously, the self-aggregation of the antibodies coating the AuNPs results in the formation of nanoparticle clusters.The addition of NaCl to increase the ionic strength fully reverses the coagulation of AuNPs (the Ab-coated AuNPs repel each other) and dissolves the Ab aggregates (the Ab interactions become repulsive, with a positive B2). The AuNPs-induced enhancement of the aggregation process can be explained by considering that the highly favorable binding of Abs on the gold surface compensates for the entropic penalty associated with Ab-Ab aggregation.The phenomenon we observed is specific to anti-L1CAM purified from rabbits and aligns with very old reports on AuNP coagulation induced specifically by the immunoglobulins present in the cerebrospinal fluid of patients suffering from neurosyphilis or multiple sclerosis (C. Lange Zeitschr. Chemotherap., 1912, 1, 44). It is reasonable to hypothesize that other antibodies exhibit this unusual behavior, so this work may aid in the interpretation of “anomalous” results that might otherwise be attributed to errors in fine-tuning AuNPs-Abs conjugation protocols

Nanovesicles as Vanillin Carriers for Antimicrobial Applications

Vanillin is a natural compound easily extracted from plants. It has neuroprotective, anti-carcinogenic, antioxidant, antimicrobial, and anti-biofilm properties. It also presents high volatility, high hydrophilicity, and low bioavailability. Nanomaterials can be used to improve pharmacodynamics, solubility, and stability and to enhance pharmacokinetics. In this work, non-ionic surfactant vesicles were synthesized as vanillin carriers: neutral niosomes formed by Span60 and cholesterol, positive charged niosomes formulated with cetyltrimethylammonium bromide (CTAB), and negatively charged niosomes formulated with sodium dodecyl sulfate (SDS). Niosomes synthesis was carried out with two commonly used methods: thin film hydration (TFH) and ethanol injection method (EIM). The niosomes synthesized were used to prepare two different materials: (i) a powder containing the lyophilized noisome with vanillin systems and (ii) a gelatin matrix film containing niosomes with vanillin. Lyophilization was carried out using maltodextrin as a cryoprotectant. The lyophilization of colloidal structures allows for storage at room temperature for long periods of time, keeping their organoleptic characteristics invariable. Niosomes were characterized before and after the lyophilization process in terms of morphological characterization, size, polydispersity index (PDI), and zeta potential. Moreover, niosomes cargo was evaluated by calculating the encapsulation efficiency (EE) and loading capacity (LC). Results showed that the use of the TFH method allowed us to obtain niosomes of 255 nm with high EE (up to 40%) and LC values higher than EIM. The lyophilization process decreased the LC of the vesicles prepared, but this decrease was mitigated by up to 20% when ionic surfactants were used on the membrane bilayer. Gelatin films are biodegradable materials suitable for food packing applications. The incorporation of a natural compound with antimicrobial activity would be a clear advantage for such an application. The films prepared were characterized in terms of morphology, water solubility, color, and transparency. Niosomes synthesized by thin film hydration had better chemical and physical properties to load vanillin. Especially in the case of application in films, niosomes with a negative charge, formed by SDS, and vanillin loaded gave better mechanical and chemical characteristics to the film

Extracellular Vesicles: Current Analytical Techniques for Detection and Quantification

Since their first observation, understanding the biology of extracellular vesicles (EV) has been an important and challenging field of study. They play a key role in the intercellular communication and are involved in important physiological and pathological functions. Therefore, EV are considered as potential biomarkers for diagnosis, prognosis, and monitoring the response to treatment in some diseases. In addition, due to their properties, EV may be used for therapeutic purposes. In the study of EV, three major points have to be addressed: 1. How to isolate EV from cell culture supernatant/biological fluids, 2. how to detect them, and 3. how to characterize and quantify. In this review, we focus on the last two questions and provide the main analytical techniques up-to-date for detection and profiling of EV. We critically analyze the advantages and disadvantages of each one, aimed to be of relevance for all researchers working on EV biology and their potential applications