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Lipid nanovectors (LNVs) represent potent and versatile tools in the field of drug delivery for a wide range of medical applications including cancer therapy and vaccines. With this Technical Note, we introduce a novel "portable", easy-to-use, and low-cost strategy for double use: (1) it allows one to both quantify the amount of cargo in LNV formulation and (2) classify the nature of formulation with the aim of chemometrics. In particular, an electrochemical strip, based on a screen-printed electrode, was exploited to detect methylene blue (MB) as the model cargo encapsulated in various liposomes (used as model LNV). The experimental setup, including release of the MB content and its electrochemical quantification were optimized through a multivariate design of experiment (DoE), obtaining a satisfactory 88-95% accuracy in comparison to standard methods. In addition, the use of principal component analysis-linear discriminant analysis (PCA-LDA) highlighted the satisfactory differentiation of liposomes. The combination of portable electroanalysis and multivariate analysis is a potent tool for enhancing quality control in the field of pharmaceutical technologies, and also in the field of diagnostics, this approach might be useful for application toward naturally occurring lipid nanoparticles, i.e., exosomes.
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Técnicas Electroquímicas , Liposomas , Liposomas/química , Azul de Metileno/química , Nanopartículas/química , Lípidos/química , Análisis de Componente Principal , Análisis DiscriminanteRESUMEN
Upon in vivo administration of nanoparticles, a protein corona forms on their surface and affects their half-life in circulation, biodistribution properties, and stability; in turn, the composition of the protein corona depends on the physico-chemical properties of the nanoparticles. We have previously observed lipid composition-dependent in vitro and in vivo microRNA delivery from lipid nanoparticles. Here, we carried out an extensive physico-chemical characterisation to understand the role of the lipid composition on the in vivo fate of lipid-based nanoparticles. We used a combination of differential scanning calorimetry (DSC), membrane deformability measurements, isothermal titration calorimetry (ITC), and dynamic light scattering (DLS) to probe the interactions between the nanoparticle surface and bovine serum albumin (BSA) as a model protein. The lipid composition influenced membrane deformability, improved lipid intermixing, and affected the formation of lipid domains while BSA binding to the liposome surface was affected by the PEGylated lipid content and the presence of cholesterol. These findings highlight the importance of the lipid composition on the protein-liposome interaction and provide important insights for the design of lipid-based nanoparticles for drug delivery applications.
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Nanopartículas , Corona de Proteínas , Liposomas , Distribución Tisular , Nanopartículas/química , Calorimetría , Albúmina Sérica Bovina/química , LípidosRESUMEN
Self-assembling nanoparticles (SANPs) promise an effective delivery of bisphosphonates or microRNAs in the treatment of glioblastoma (GBM) and are obtained through the sequential mixing of four components immediately before use. The self-assembling approach facilitates technology transfer, but the complexity of the SANP preparation protocol raises significant concerns in the clinical setting due to the high risk of human errors during the procedure. In this work, it was hypothesized that the SANP preparation protocol could be simplified by using freeze-dried formulations. An in-depth thermodynamic study was conducted on solutions of different cryoprotectants, namely sucrose, mannitol and trehalose, to test their ability to stabilize the produced SANPs. In addition, the ability of SANPs to deliver drugs after lyophilization was assessed on selected formulations encapsulating zoledronic acid in vitro in the T98G GBM cell line and in vivo in an orthotopic mouse model. Results showed that, after lyophilization optimization, freeze-dried SANPs encapsulating zoledronic acid could retain their delivery ability, showing a significant inhibition of T98G cell growth both in vitro and in vivo. Overall, these results suggest that freeze-drying may help boost the industrial development of SANPs for the delivery of drugs to the brain.
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Glioblastoma , Nanopartículas , Animales , Difosfonatos/farmacología , Liofilización , Glioblastoma/tratamiento farmacológico , Ratones , Sacarosa , Trehalosa , Ácido ZoledrónicoRESUMEN
Short-chain alcohols (i.e., ethanol) can induce membrane interdigitation in saturated-chain phosphatidylcholines (PCs). In this process, alcohol molecules intercalate between phosphate heads, increasing lateral separation and favoring hydrophobic interactions between opposing acyl chains, which interpenetrate forming an interdigitated phase. Unraveling mechanisms underlying the interactions between ethanol and model lipid membranes has implications for cell biology, biochemistry, and for the formulation of lipid-based nanocarriers. However, investigations of ethanol-lipid membrane systems have been carried out in deionized water, which limits their applicability. Here, using a combination of small- and wide-angle X-ray scattering, small-angle neutron scattering, and all-atom molecular dynamics simulations, we analyzed the effect of varying CaCl2 and NaCl concentrations on ethanol-induced interdigitation. We observed that while ethanol addition leads to the interdigitation of bulk phase 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers in the presence of CaCl2 and NaCl regardless of the salt concentration, the ethanol-induced interdigitation of vesicular DPPC depends on the choice of cation and its concentration. These findings unravel a key role for cations in the ethanol-induced interdigitation of lipid membranes in either bulk phase or vesicular form.
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1,2-Dipalmitoilfosfatidilcolina , Etanol , Cationes , Fosfatidilcolinas , Dispersión del Ángulo PequeñoRESUMEN
Extracellular vesicles (EVs) are secreted by the vast majority of cells and are being intensively studied due to their emerging involvement in a variety of cellular communication processes. However, the study of their cellular uptake and fate has been hampered by difficulty in imaging EVs against the cellular background. Here, we show that EVs combined with hydrophobic gold nanoclusters (AuNCs) can self-assemble into supraparticles, offering an excellent labeling strategy for high-resolution electron microscopic imaging in vitro. We have tracked and visualized the reuptake of breast cancer cell-derived EV AuNC supraparticles into their parent cells, from early endocytosis to lysosomal degradation, using focused ion beam-scanning electron microscopy (FIB-SEM). The presence of gold within the EVs and lysosomes was confirmed via DF-STEM EDX analysis of lift-out sections. The demonstrated formation of AuNC EV supraparticles will facilitate future applications in EV imaging as well as the EV-assisted cellular delivery of AuNCs.
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Liposomes are well-established systems for drug delivery and biosensing applications. The design of a liposomal carrier requires careful choice of lipid composition and formulation method. These determine many vesicle properties including lamellarity, which can have a strong effect on both encapsulation efficiency and the efflux rate of encapsulated active compounds. Despite this, a comprehensive study on how the lipid composition and formulation method affect vesicle lamellarity is still lacking. Here, we combine small-angle neutron scattering and cryogenic transmission electron microscopy to study the effect of three different well-established formulation methods followed by extrusion through 100 nm polycarbonate membranes on the resulting vesicle membrane structure. Specifically, we examine vesicles formulated from the commonly used phospholipids 1-palmitoyl-2-oleoyl- sn-glycero-3-phosphocholine (POPC), 1,2-dipalmitoyl- sn-glycero-3-phosphocholine (DPPC) and 1,2-dioleoyl- sn-glycero-3-phosphocholine (DOPC) via film hydration followed by (i) agitation on a shaker or (ii) freeze-thawing, or (iii) the reverse-phase evaporation vesicle method. After extrusion, up to half of the total lipid content is still assembled into multilamellar structures. However, we achieved unilamellar vesicle populations when as little as 0.1 mol % PEG-modified lipid was included in the vesicle formulation. Interestingly, DPPC with 5 mol % PEGylated lipid produces a combination of cylindrical micelles and vesicles. In conclusion, our results provide important insights into the effect of the formulation method and lipid composition on producing liposomes with a defined membrane structure.
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Among non-viral vectors, lipid nanovectors are considered the gold standard for the delivery of RNA therapeutics. The success of lipid nanoparticles for RNA delivery, with three products approved for human use, has stimulated further investigation into RNA therapeutics for different pathologies. This requires decoding the pathological intracellular processes and tailoring the delivery system to the target tissue and cells. The complexity of the lipid nanovectors morphology originates from the assembling of the lipidic components, which can be elicited by various methods able to drive the formation of nanoparticles with the desired organization. In other cases, pre-formed nanoparticles can be mixed with RNA to induce self-assembly and structural reorganization into RNA-loaded nanoparticles. In this review, the most relevant lipid nanovectors and their potentialities for RNA delivery are described on the basis of the assembling mechanism and of the particle architecture.
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Nanopartículas , ARN , Humanos , Liposomas , Nanopartículas/química , LípidosRESUMEN
In the medical field, extracellular vesicles (EVs) are gaining importance as they act as cells mediators. These are phospholipid bilayer vesicles and contain crucial biochemical information about their mother cells being carrier of different biomolecules such as small molecules, proteins, lipids, and nucleic acids. After release into the extracellular matrix, they enter the systemic circulation and can be found in all human biofluids. Since EVs reflect the state of the cell of origin, there is exponential attention as potential source of new circulating biomarkers for liquid biopsy. The use of EVs in clinical practice faces several challenges that need to be addressed: these include the standardization of lysis protocols, the availability of low-cost reagents and the development of analytical tools capable of detecting biomarkers. The process of lysis is a crucial step that can impact all subsequent analyses, towards the development of novel analytical strategies. To aid researchers to support the evolution of measurement science technology, this tutorial review evaluates and discuss the most commonly protocols used to characterize the contents of EVs, including their advantages and disadvantages in terms of experimental procedures, time and equipment. The purpose of this tutorial review is to offer practical guide to researchers which are intended to develop novel analytical approaches. Some of the most significant applications are considered, highlighting their main characteristics divided per mechanism of action. Finally, comprehensive tables which provide an overview at a glance are provided to readers.
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Vesículas Extracelulares , Ácidos Nucleicos , Humanos , Vesículas Extracelulares/química , Biopsia Líquida/métodos , Biomarcadores/análisis , Ácidos Nucleicos/análisis , Muerte CelularRESUMEN
MicroRNA (miRNA), by post-transcriptionally regulating the expression of genes involved in stroke response, represents important effectors in stroke pathophysiology. Recently, the 103/107 miRNA family emerged as a possible therapeutic target in stroke, as it controls the expression of sodium calcium exchanger 1, a plasma membrane transporter that plays a fundamental role in stroke pathophysiology. Although the neuroprotective properties of this and other miRNAs are promising, several pharmacokinetic drawbacks remain to be faced for the development of a translatable therapy based on small RNAs in CNS diseases. In the present study, to overcome these limitations, the anti-miRNA103/107 was encapsulated in specific preparations of lipid nanoparticles (LNPs), and their effectiveness was evaluated both in an in vitro model of hypoxia represented by primary neuronal cortical cultures exposed to oxygen and glucose deprivation followed by reoxygenation, and in an in vivo model of stroke obtained in rats exposed to transient occlusion of the middle cerebral artery. The results of the present study demonstrated that the encapsulation of anti-miRNA103/107 in transferrin-conjugated PEG-stabilized LNPs allowed the blood-brain barrier crossing and significantly reduced brain ischemic damage. The present achievements pave the way for the exploitation of a systemic intravenous miRNA delivery strategy in stroke therapy.
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Chronic wounds are marked by an extended healing period during which damaged tissues fail to undergo orderly and timely repair. Examples of chronic wounds encompass venous ulcers, pressure ulcers, and diabetic foot ulcers. The process of wound healing is complex and dynamic, relying on the interplay and response among various cells and mediators. In this study, four marketed wound dressing products based on cotton gauzes impregnated with different semisolid products (namely Betadine® 10%, Connettivina® Bio Plus Fitostimoline® Plus, and Non-Ad® gauzes) have been characterized for their physicochemical properties and ex vivo behaviors. More in detail, the pH and rheological features of semisolid formulations impregnating the gauzes were analyzed along with their ability to adhere to the gauzes. The most promising ones were selected and compared in ex vivo experiments on fresh pig skin. The pH measurements showed an acidic environment for all the tested solutions, albeit with variations in mean values, ranging from 2.66 to 4.50. The outcomes of rheological studies demonstrated that all the semisolid preparations impregnating the gauzes exhibited a pseudoplastic behavior, with significant differences in the pseudoplasticity index across the preparations, which is likely to influence their ability to adhere to the gauze. A rheological study in oscillatory mode revealed rheological behavior typical of a viscous solution only for the cream impregnating non-paraffin gauzes. The other products exhibited rheological behavior typical of a weak gel, which is expected to be advantageous as regards the capability of the semisolid preparation to create and maintain the space within the wound and to provide protection to the injured tissue. Results of ex vivo experiments demonstrated that Fitostimoline® Plus was more effective than Connettivina® Bio Plus in promoting both skin hydration and energy.
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BACKGROUND: In non-small cell lung cancer (NSCLC) the efficacy of chemo-immunotherapy is affected by the high expression of drug efflux transporters as ABCC1 and by the low expression of ABCA1, mediating the isopentenyl pyrophosphate (IPP)-dependent anti-tumor activation of Vγ9Vδ2 T-lymphocytes. In endothelial cells ABCA1 is a predicted target of the transcription factor EB (TFEB), but no data exists on the correlation between TFEB and ABC transporters involved in the chemo-immuno-resistance in NSCLC. METHODS: The impact of TFEB/ABCC1/ABCA1 expression on NSCLC patients' survival was analyzed in the TCGA-LUAD cohort and in a retrospective cohort of our institution. Human NSCLC cells silenced for TFEB (shTFEB) were analyzed for ABC transporter expression, chemosensitivity and immuno-killing. The chemo-immuno-sensitizing effects of nanoparticles encapsulating zoledronic acid (NZ) on shTFEB tumors and on tumor immune-microenvironment were evaluated in Hu-CD34+ mice by single-cell RNA-sequencing. RESULTS: TFEBlowABCA1lowABCC1high and TFEBhighABCA1highABCC1low NSCLC patients had the worst and the best prognosis, respectively, in the TCGA-LUAD cohort and in a retrospective cohort of patients receiving platinum-based chemotherapy or immunotherapy as first-line treatment. By silencing shTFEB in NSCLC cells, we demonstrated that TFEB was a transcriptional inducer of ABCA1 and a repressor of ABCC1. shTFEB cells had also a decreased activity of ERK1/2/SREBP2 axis, implying reduced synthesis and efflux via ABCA1 of cholesterol and its intermediate IPP. Moreover, TFEB silencing reduced cholesterol incorporation in mitochondria: this event increased the efficiency of OXPHOS and the fueling of ABCC1 by mitochondrial ATP. Accordingly, shTFEB cells were less immuno-killed by the Vγ9Vδ2 T-lymphocytes activated by IPP and more resistant to cisplatin. NZ, which increased IPP efflux but not OXPHOS and ATP production, sensitized shTFEB immuno-xenografts, by reducing intratumor proliferation and increasing apoptosis in response to cisplatin, and by increasing the variety of anti-tumor infiltrating cells (Vγ9Vδ2 T-lymphocytes, CD8+T-lymphocytes, NK cells). CONCLUSIONS: This work suggests that TFEB is a gatekeeper of the sensitivity to chemotherapy and immuno-killing in NSCLC, and that the TFEBlowABCA1lowABCC1high phenotype can be predictive of poor response to chemotherapy and immunotherapy. By reshaping both cancer metabolism and tumor immune-microenvironment, zoledronic acid can re-sensitize TFEBlow NSCLCs, highly resistant to chemo- and immunotherapy.
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Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice , Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Humanos , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/patología , Carcinoma de Pulmón de Células no Pequeñas/inmunología , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice/metabolismo , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice/genética , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/inmunología , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Ratones , Animales , Femenino , Inmunoterapia/métodos , Línea Celular Tumoral , Masculino , Estudios RetrospectivosRESUMEN
Neurodegenerative diseases are characterized by mitochondrial dysfunction leading to abnormal levels of reactive oxygen species (ROS), making the use of ROS-scavenging nanomaterials a promising therapeutic approach. Here, we combined the unique ROS-scavenging properties of cerium-based nanomaterials with the lipid self-assembling nanoparticles (SANP) technology. We optimized the preparation of cerium-doped SANP (Ce-SANP) and characterized the formulations in terms of both physiochemical and biological properties. Ce-SANP exhibited good colloidal properties and were able to mimic the activity of two ROS-scavenging enzymes, namely peroxidase and super oxide dismutase. Under ischemia-like conditions, Ce-SANP could rescue neuronal cells from mitochondrial suffering by reducing ROS production and preventing ATP level reduction. Furthermore, Ce-SANP prevented mitochondrial Ca2+ homeostasis dysfunction, partially restoring mitochondrial Ca2+ handling. Taken together, these results highlight the potential of the anti-oxidant Ce-SANP platform technology to manage ROS levels and mitochondrial function for the treatment of neurodegenerative diseases.
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Nanodiamonds are innovative nanocrystalline carbon particles able to deliver chemically conjugated miRNAs. In oncology, the use of miRNA-based therapies may represent an advantage, based on their ability to simultaneously target multiple intracellular oncogenic targets. Here, nanodiamonds were tested and optimized to deliver miR-34a, a miRNA playing a key role in inhibiting tumor development and progression in many cancers. The physical-chemical properties of nanodiamonds were investigated suggesting electrical stability and uniformity of structure and size. Moreover, we evaluated nanodiamond cytotoxicity on two breast cancer cell models and confirmed their excellent biocompatibility. Subsequently, nanodiamonds were conjugated with miR-34a, using the chemical crosslinker polyethyleneimine; real-time PCR analysis revealed a higher level of miR-34a in cancer cells treated with the different formulations of nanodiamonds than with commercial transfectant. A significant and early nanodiamond-miR-34a uptake was recorded by FACS and fluorescence microscopy analysis in MCF7 and MDA-MB-231 cells. Moreover, nanodiamond-miR-34a significantly inhibited both cell proliferation and migration. Finally, a remarkable anti-tumor effect of miR-34a-conjugated nanodiamonds was observed in both heterotopic and orthotopic murine xenograft models. In conclusion, this study provides a rationale for the development of new therapeutic strategies based on use of miR-34a delivered by nanodiamonds to improve the clinical treatment of neoplasms.
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The use of chemotherapeutic agents such as docetaxel (DTX) in anticancer therapy is often correlated to side effects and the occurrence of drug resistance, which substantially impair the efficacy of the drug. Here, we demonstrate that self-emulsifying drug delivery systems (SEDDS) coated with enoxaparin (Enox) are a promising strategy to deliver DTX in resistant tumors. DTX partition studies between the SEDDS pre-concentrate and the release medium (water) suggest that the drug is well retained within the SEDDS upon dilution in the release medium. All SEDDS formulations show droplets with a mean diameter between 110 and 145 nm following dilution in saline and negligible hemolytic activity; the droplet size remains unchanged upon sterilization. Enox-coated SEDDS containing DTX exhibit an enhanced inhibition of cell growth compared to the control on cells of different solid tumors characterized by high levels of FGFR, which is due to an increased DTX internalization mediated by Enox. Moreover, only Enox-coated SEDDS are able to restore the sensitivity to DTX in resistant cells expressing MRP1 and BCRP by inhibiting the activity of these two main efflux transporters for DTX. The efficacy and safety of these formulations is also confirmed in vivo in resistant non-small cell lung cancer xenografts.
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Thermoresponsive polymers with the appropriate structure form physical networks upon changes in temperature, and they find utility in formulation science, tissue engineering, and drug delivery. Here, we report a cost-effective biocompatible alternative, namely OEGMA30015-b-BuMA26-b-DEGMA13, which forms gels at low concentrations (as low as 2% w/w); OEGMA300, BuMA, and DEGMA stand for oligo(ethylene glycol) methyl ether methacrylate (MM = 300 g mol-1), n-butyl methacrylate, and di(ethylene glycol) methyl ether methacrylate, respectively. This polymer is investigated in depth and is compared to its commercially available counterpart, Poloxamer P407 (Pluronic F127). To elucidate the differences in their macroscale gelling behavior, we investigate their nanoscale self-assembly by means of small-angle neutron scattering and simultaneously recording their rheological properties. Two different gelation mechanisms are revealed. The triblock copolymer inherently forms elongated micelles, whose length increases by temperature to form worm-like micelles, thus promoting gelation. In contrast, Pluronic F127's micellization is temperature-driven, and its gelation is attributed to the close packing of the micelles. The gel structure is analyzed through cryogenic scanning and transmission electron microscopy. Ex vivo gelation study upon intracameral injections demonstrates excellent potential for its application to improve drug residence in the eye.
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Lipid nanoparticles (LNPs) are versatile structures with tunable physicochemical properties that are ideally suited as a platform for vaccine delivery and RNA therapeutics. A key barrier to LNP rational design is the inability to relate composition and structure to intracellular processing and function. Here Single Particle Automated Raman Trapping Analysis (SPARTA) is combined with small-angle X-ray and neutron scattering (SAXS/SANS) techniques to link LNP composition with internal structure and morphology and to monitor dynamic LNP-phospholipase D (PLD) interactions. This analysis demonstrates that PLD, a key intracellular trafficking mediator, can access the entire LNP lipid membrane to generate stable, anionic LNPs. PLD activity on vesicles with matched amounts of enzyme substrate is an order of magnitude lower, indicating that the LNP lipid membrane structure can be used to control enzyme interactions. This represents an opportunity to design enzyme-responsive LNP solutions for stimuli-responsive delivery and diseases where PLD is dysregulated.
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Lípidos , Nanopartículas , Lípidos/química , Liposomas , Nanopartículas/química , Fosfolipasas , ARN Interferente Pequeño/química , Dispersión del Ángulo Pequeño , Difracción de Rayos XRESUMEN
Glioblastoma multiforme (GBM) is the most frequent and aggressive form of primary brain tumor in the adult population; its high recurrence rate and resistance to current therapeutics urgently demand a better therapy. Regulation of protein stability by the ubiquitin proteasome system (UPS) represents an important control mechanism of cell growth. UPS deregulation is mechanistically linked to the development and progression of a variety of human cancers, including GBM. Thus, the UPS represents a potentially valuable target for GBM treatment. Using an integrated approach that includes proteomics, transcriptomics and metabolic profiling, we identify praja2, a RING E3 ubiquitin ligase, as the key component of a signaling network that regulates GBM cell growth and metabolism. Praja2 is preferentially expressed in primary GBM lesions expressing the wild-type isocitrate dehydrogenase 1 gene (IDH1). Mechanistically, we found that praja2 ubiquitylates and degrades the kinase suppressor of Ras 2 (KSR2). As a consequence, praja2 restrains the activity of downstream AMP-dependent protein kinase in GBM cells and attenuates the oxidative metabolism. Delivery in the brain of siRNA targeting praja2 by transferrin-targeted self-assembling nanoparticles (SANPs) prevented KSR2 degradation and inhibited GBM growth, reducing the size of the tumor and prolonging the survival rate of treated mice. These data identify praja2 as an essential regulator of cancer cell metabolism, and as a potential therapeutic target to suppress GBM growth.
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Neoplasias Encefálicas , Glioblastoma , Adulto , Animales , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Glioblastoma/metabolismo , Humanos , Ratones , Complejo de la Endopetidasa Proteasomal/metabolismo , Transducción de Señal , UbiquitinaRESUMEN
It has been demonstrated that some commonly used Extracellular Vesicle (EV) isolation techniques can lead to substantial contamination with non-EV factors. Whilst it has been established that this impacts the identification of biomarkers, the impact on apparent EV bioactivity has not been explored. Extracellular vesicles have been implicated as critical mediators of therapeutic human mesenchymal stem cell (hMSC) paracrine signalling. Isolated hMSC-EVs have been used to treat multiple in vitro and in vivo models of tissue damage. However, the relative contributions of EVs and non-EV factors have not been directly compared. The dependence of hMSC paracrine signalling on EVs was first established by ultrafiltration of hMSC-conditioned medium to deplete EVs, which led to a loss of signalling activity. Here, we show that this method also causes depletion of non-EV factors, and that when this is prevented proangiogenic signalling activity is fully restored in vitro. Subsequently, we used size-exclusion chromatography (SEC) to separate EVs and soluble proteins to directly and quantitatively compare their relative contributions to signalling. Non-EV factors were found to be necessary and sufficient for the stimulation of angiogenesis and wound healing in vitro. EVs in isolation were found to be capable of potentiating signalling only when isolated by a low-purity method, or when used at comparatively high concentrations. These results indicate a potential for contaminating soluble factors to artefactually increase the apparent bioactivity of EV isolates and could have implications for future studies on the biological roles of EVs.
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Hydrogels are formed using various triggers, including light irradiation, pH adjustment, heating, cooling, or chemical addition. Here, a new method for forming hydrogels is introduced: ultrasound-triggered enzymatic gelation. Specifically, ultrasound is used as a stimulus to liberate liposomal calcium ions, which then trigger the enzymatic activity of transglutaminase. The activated enzyme catalyzes the formation of fibrinogen hydrogels through covalent intermolecular crosslinking. The catalysis and gelation processes are monitored in real time and both the enzyme kinetics and final hydrogel properties are controlled by varying the initial ultrasound exposure time. This technology is extended to microbubble-liposome conjugates, which exhibit a stronger response to the applied acoustic field and are also used for ultrasound-triggered enzymatic hydrogelation. To the best of the knowledge, these results are the first instance in which ultrasound is used as a trigger for either enzyme catalysis or enzymatic hydrogelation. This approach is highly versatile and can be readily applied to different ion-dependent enzymes or gelation systems. Moreover, this work paves the way for the use of ultrasound as a remote trigger for in vivo hydrogelation.
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Enzimas/química , Hidrogeles/química , Ondas Ultrasónicas , Cloruro de Calcio/química , Catálisis , Reactivos de Enlaces Cruzados/química , Fibrinógeno/química , Cinética , Liposomas/química , Microburbujas , Fosfatidiletanolaminas/química , Fosforilcolina/química , Polietilenglicoles/químicaRESUMEN
Many diseases are associated with the dysregulated activity of enzymes, such as matrix metalloproteinases (MMPs). This dysregulation can be leveraged in drug delivery to achieve disease- or site-specific cargo release. Self-assembled polymeric nanoparticles are versatile drug carrier materials due to the accessible diversity of polymer chemistry. However, efficient loading of sensitive cargo, such as proteins, and introducing functional enzyme-responsive behaviour remain challenging. Herein, peptide-crosslinked, temperature-sensitive nanogels for protein delivery were designed to respond to MMP-7, which is overexpressed in many pathologies including cancer and inflammatory diseases. The incorporation of N-cyclopropylacrylamide (NCPAM) into N-isopropylacrylamide (NIPAM)-based copolymers enabled us to tune the polymer lower critical solution temperature from 33 to 44 °C, allowing the encapsulation of protein cargo and nanogel-crosslinking at slightly elevated temperatures. This approach resulted in nanogels that were held together by MMP-sensitive peptides for enzyme-specific protein delivery. We employed a combination of cryogenic transmission electron microscopy (cryo-TEM), dynamic light scattering (DLS), small angle neutron scattering (SANS), and fluorescence correlation spectroscopy (FCS) to precisely decipher the morphology, self-assembly mechanism, enzyme-responsiveness, and model protein loading/release properties of our nanogel platform. Simple variation of the peptide linker sequence and combining multiple different crosslinkers will enable us to adjust our platform to target specific diseases in the future.