RESUMEN
Nanoscale and microscale cell-derived extracellular vesicle types and subtypes are of significant interest to researchers in biology and medicine. Extracellular vesicles (EVs) have diagnostic and therapeutic potential in terms of biomarker and nanomedicine applications. To enable such applications, EVs must be isolated from biological fluids or separated from other EV types. Developing methods to fractionate EVs is of great importance to EV researchers. Our goal was to begin to develop a device that would separate medium EVs (mEVs, traditionally termed microvesicles or shedding vesicles) and small EVs (sEVs, traditionally termed exosomes) by elasto-inertial effect. We sought to develop a miniaturized technology that works similar to and provides the benefits of differential ultracentrifugation but is more suitable for EV-based microfluidic applications. The aim of this study was to determine whether we could use elasto-inertial focusing to re-isolate and recover U87 mEVs and sEVs from a mixture of mEVs and sEVs isolated initially by one round of differential ultracentrifugation. The studied spiral channel device can continuously process 5 ml of sample fluid per hour. Using the channel, sEVs and mEVs were recovered and re-isolated from a mixture of U87 glioma cell-derived mEVs and sEVs pre-isolated by one round of differential ultracentrifugation. Following two passes through the spiral channel, approximately 55% of sEVs were recovered with 6% contamination by mEVs (the recovered sEVs contained 6% of the total mEVs). In contrast, recovery of U87 mEVs and sEVs re-isolated using a typical second centrifugation wash step was only 8% and 53%, respectively. The spiral channel also performed similar to differential ultracentrifugation in reisolating sEVs while significantly improving mEV reisolation from a mixture of U87 sEVs and mEVs. Ultimately this technology can also be coupled to other microfluidic EV isolation methods in series and/or parallel to improve isolation and minimize loss of EV subtypes.
Asunto(s)
Exosomas , Vesículas Extracelulares , Glioblastoma , Centrifugación , Medios de Cultivo , Humanos , UltracentrifugaciónRESUMEN
In this work, a new high-volume, continuous particle separation device that separates based upon size and charge is described. Two continuous flow-electrical-split-flow lateral transport thin (Fl-El-SPLITT) device architectures (a platinum electrode on a porous membrane and a porous graphite electrode under a membrane) were developed and shown to improve particle separations over a purely electrical-SPLITT device. The graphite FL-El-SPLITT device architecture achieved the best separation of approximately 60% of small (28 nm) vs large (1000 nm) polystyrene particles. Fl-El-SPLITT (platinum) achieved a 75% separation on a single pass using these same particles. Fl-El-SPLITT (platinum) achieved a moderate 26% continuous separation of U87 glioma cell-derived small extracellular vesicles (EVs) from medium EVs. Control parameter testing showed that El-SPLITT continuously directed particle motility within a channel to exit a selected port based upon the applied voltage using either direct current or alternating current. The transition from one port to the other was dependent upon the voltage applied. Both large and small polystyrene particles transitioned together rather than separating at each of the applied voltages. These data present the first ever validation of El-SPLITT in continuous versus batch format. The Fl-El-SPLITT device architecture, monitoring, and electrical and fluid interfacing systems are described in detail for the first time. Capabilities afforded to the system by the flow addition include enhanced particle separation as well as the ability to filter out small particles or desalinate fluids. High-throughput continuous separations based upon electrophoretic mobility will be streamlined by this new technique that combines electrical and flow fields into a single device.
Asunto(s)
Fraccionamiento Químico , Electricidad , Tamaño de la Partícula , Fenómenos FísicosRESUMEN
Although many properties for small extracellular vesicles (sEVs, formerly termed "exosomes") isolated at â¼100â¯000g are known, a wide range of values are reported for their electrophoretic mobility (EM) measurements. This paper reports for the first time the effect of dilution on the EM of U87 glioblastoma cell-derived and plasma-derived sEVs and medium size EVs (mEVs, commonly termed "oncosomes") preisolated by differential centrifugation. Furthermore, the effect of resalting on the EM of sEVs and mEVs was evaluated. The EM of U87 sEVs and U87 mEVs showed an increase as the salt concentration decreased to 0.005% of the initial salt concentration. However, for the plasma sEVs and plasma mEVs, the electrophoretic mobility increased as the salt concentration decreased to 0.01% of the initial salt concentration and then increased to its initial value when the salt concentration decreased to 0.005% of the initial salt concentration. For both U87 and plasma sEVs and mEVs, the EM remained almost constant when the concentration of the particles changed and the salt concentration was kept the same as its initial value. This indicates that the EM of EVs is only a function of the salt concentration of the buffer and is independent of the concentration of the particles. The sEVs and mEVs were separated with cyclical ElFFF for the first time. The results indicate that ElFFF was able to fractionate the EVs, and a crescent-shaped trend was found for the retention time when the applied AC voltage was altered (increased).
Asunto(s)
Centrifugación/métodos , Fraccionamiento Químico/métodos , Técnicas Electroquímicas , Vesículas Extracelulares/química , Glioblastoma/química , Línea Celular Tumoral , HumanosRESUMEN
Melanoma-derived small extracellular vesicles (sEVs) participate in tumor pathogenesis. Tumor pathogenesis is highly dependent on inflammatory processes. Given the potential for melanoma sEVs to carry tumor biomarkers, we explored the hypothesis that they may contain inflammation-related mRNA content. Biophysical characterization showed that human primary melanocyte-derived sEVs trended toward being smaller and having less negative (more neutral) zeta potential than human melanoma sEVs (A-375, SKMEL-28, and C-32). Using primary melanocyte sEVs as the control population, RT-qPCR array results demonstrated similarities and differences in gene expression between melanoma sEV types. Upregulation of pro-angiogenic chemokine ligand CXCL1, CXCL2, and CXCL8 mRNAs in A-375 and SKMEL-28 melanoma sEVs was the most consistent finding. This paralleled increased production of CXCL1, CXCL2, and CXCL8 proteins by A-375 and SKMEL-28 sEV source cells. Overall, the use of primary melanocyte sEVs as a control sEV reference population facilitated the detection of inflammation-related melanoma sEV mRNA content.
Asunto(s)
Vesículas Extracelulares/genética , Inflamación/genética , Melanocitos/patología , Melanoma/genética , ARN Mensajero/genética , Biomarcadores de Tumor/genética , Línea Celular Tumoral , Quimiocinas CXC/genética , Humanos , Regulación hacia Arriba/genéticaRESUMEN
The influence of buffer substitution and dilution effects on exosome size and electrophoretic mobility were shown for the first time. Cyclical electrical field flow fractionation (Cy-El-FFF) in various substituted fluids was applied to exosomes and other particles. Tested carrier fluids of deionized (DI) water, 1× phosphate buffered saline (PBS), 0.308 M trehalose, and 2% isopropyl alcohol (IPA) influenced Cy-El-FFF-mediated isolation of A375 melanoma exosomes. All fractograms revealed a crescent-shaped trend in retention times with increasing voltage with the maximum retention time at â¼1.3 V AC. A375 melanoma exosome recovery was approximately 70-80% after each buffer substitution, and recovery was independent of whether the sample was substituted into 1× PBS or DI water. Exosome dilution in deionized water produced a U-shaped dependence on electrophoretic mobility. The effect of dilution using 1× PBS buffer revealed a very gradual change in electrophoretic mobility of exosomes from â¼-1.6 to -0.1 µm cm/s V, as exosome concentration was decreased. This differed from the use of DI water, where a large change from â¼-5.5 to -0.1 µm cm/s V over the same dilution range was observed. Fractograms of separated A375 melanoma exosomes in two substituted low-ionic-strength buffers were compared with synthetic particle fractograms. Overall, the ability of Cy-El-FFF to separate exosomes based on their size and charge is a highly promising, label-free approach to initially catalogue and purify exosome subtypes for biobanking as well as to enable further exosome subtype interrogations.
Asunto(s)
Exosomas/química , Solventes/química , 2-Propanol/química , Tampones (Química) , Línea Celular Tumoral , Fraccionamiento de Campo-Flujo/métodos , Humanos , Nanopartículas/química , Concentración Osmolar , Fosfatos/química , Poliestirenos/química , Solución Salina/química , Trehalosa/química , Agua/químicaRESUMEN
Macrophages are key participants in melanoma growth and survival. In general, macrophages can be classified as M1 or M2 activation phenotypes. Increasing evidence demonstrates that melanoma exosomes also facilitate tumor survival and metastasis. However, the role of melanoma exosomes in directly influencing macrophage function is poorly understood. Herein, we investigated the hypothesis that natural melanoma exosomes might directly influence macrophage polarization. To explore this hypothesis, ELISA, RT-qPCR, and macrophage functional studies were performed in vitro using an established source of melanoma exosomes (B16-F10). ELISA results for melanoma exosome induction of common M1 and M2 cytokines in RAW 264.7 macrophages, revealed that melanoma exosomes do not polarize macrophages exclusively in the M1 or M2 direction. Melanoma exosomes induced the M1 and M2 representative cytokines TNF-α and IL-10 respectively. Further assessment, using an RT-qPCR array with RAW 264.7 and primary macrophages, confirmed and extended the ELISA findings. Upregulation of markers common to both M1 and M2 polarization phenotypes included CCL22, IL-12B, IL-1ß, IL-6, i-NOS, and TNF-α. The M2 cytokine TGF-ß was upregulated in primary but not RAW 264.7 macrophages. Pro-tumor functions have been attributed to each of these markers. Macrophage functional assays demonstrated a trend toward increased i-NOS (M1) to arginase (M2) activity. Collectively, the results provide the first evidence that melanoma exosomes can induce a mixed M1 and M2 pro-tumor macrophage activation phenotype.
Asunto(s)
Polaridad Celular , Exosomas/metabolismo , Macrófagos/patología , Melanoma Experimental/patología , Animales , Arginasa/metabolismo , Biomarcadores/metabolismo , Polaridad Celular/efectos de los fármacos , Exosomas/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Interleucina-4/metabolismo , Lipopolisacáridos/farmacología , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Ratones , Ratones Endogámicos C57BL , Óxido Nítrico Sintasa de Tipo II/metabolismo , Células RAW 264.7 , Regulación hacia Arriba/efectos de los fármacosRESUMEN
AS1411 is a quadruplex-forming DNA oligonucleotide that functions as an aptamer to target nucleolin, a protein present on the surface of cancer cells. Clinical trials of AS1411 have indicated it is well tolerated with evidence of therapeutic activity, but improved pharmacology and potency may be required for optimal efficacy. In this report, we describe how conjugating AS1411 to 5 nm gold nanospheres influences its activities in vitro and in vivo. We find that the AS1411-linked gold nanospheres (AS1411-GNS) are stable in aqueous and serum-containing solutions. Compared to unconjugated AS1411 or GNS linked to control oligonucleotides, AS1411-GNS have superior cellular uptake and markedly increased antiproliferative/cytotoxic effects. Similar to AS1411, AS1411-GNS show selectivity for cancer cells compared to non-malignant cells. In a mouse model of breast cancer, systemic administration of AS1411-GNS could completely inhibit tumor growth with no signs of toxicity. These results suggest AS1411-GNS are promising candidates for clinical translation.