Total Exosome Isolation Reagent Research Articles

Evaluation of exosomes encapsulated recombinant Interleukin-29 for its in vitro anticancer studies.

Exosomes have recently been considered ideal biotherapeutic nanocarriers that broaden the frontiers of current drug delivery systems to overcome the shortcomings associated with cytokine-based immunotherapy. Using this approach, the current study aimed to assess anti-proliferative activity of purified IL-29 and exosomes encapsulated IL-29. The IL-29+pET-28a construct was transformed into Rosetta 2(DE3) cells which was used for the large-scale production of IL-29. Exosomes isolated from H1HeLa, and SF-767 cells using Total Exosome Isolation reagent were loaded with IL-29 via sonication. Isolation of exosomes was validated using their core protein signature by western blotting and specific miRNA profiles by RT-PCR. The drug loading efficiency of exosomes derived from H1HeLa cells was higher than that of SF-767-derived exosomes. The drug release kinetics of IL-29 encapsulated exosomes exhibited stable release of the recombinant drug. Around 50% of all cancer cell lines survived when IL-29 was administered at a concentration of 20µg/mL. A survival rate of less than 10% was observed when cells were treated with 20µg/mL IL-29 loaded exosomes. It was concluded that IL-29 loaded exosomes had a more significant cytotoxic effect against cancer cells, which might be attributed to sustained drug release, improved half-life, superior targeting efficacy, capacity to harness endogenous intracellular trafficking pathways, and heightened biocompatibility of exosomes.

Hypoxia-Elicited Mesenchymal Stem Cell-Derived Small Extracellular Vesicles Alleviate Myocardial Infarction by Promoting Angiogenesis through the miR-214/Sufu Pathway.

Myocardial infarction is a leading cause of mortality worldwide. Angiogenesis in the infarct border zone is vital for heart function restoration after myocardial infarction. Hypoxia-induced MSC modification is a safe and effective approach for angiogenesis in clinical therapy; however, the mechanism still requires further investigation. In our study, we preconditioned human umbilical cord mesenchymal stem cells (huMSCs) with hypoxia and isolated the small extracellular vesicles (sEVs) to promote cardiac repair. We also investigated the potential mechanisms. huMSCs were preconditioned with hypoxia (1% O2 and 5% CO2 at 37°C for 48 hours), and their sEVs were isolated using the Total Exosome Isolation reagent kit. To explore the role of miR-214 in MSC-derived sEVs, sEVs with low miR-214 expression were prepared by transfecting miR-214 inhibitor into huMSCs before hypoxia pretreatment. Scratch assays and tube formation assays were performed in sEVs cocultured with HUVECs to assess the proangiogenic capability of MSC-sEVs and MSChyp-sEVs. Rat myocardial infarction models were used to investigate the ability of miR-214-differentially expressed sEVs in cardiac repair. Echocardiography, Masson's staining, and immunohistochemical staining for CD31 were performed to assess cardiac function, the ratio of myocardial fibrosis, and the capillary density after sEV implantation. The potential mechanism by which MSChyp-sEVs enhance angiogenesis was explored in vitro by RT-qPCR and western blotting. Tube formation and scratch assays demonstrated that the proangiogenic capability of huMSC-derived sEVs was enhanced by hypoxia pretreatment. Echocardiography and Masson's staining showed greater improvements in heart function and less ventricular remodeling after MSChyp-sEV transplantation. The angiogenic capability was reduced following miR-214 knockdown in MSChyp-sEVs. Furthermore, Sufu, a target of miR-214, was decreased, and hedgehog signaling was activated in HUVECs. We found that hypoxia induced miR-214 expression both in huMSCs and their sEVs. Transplantation of MSChyp-sEVs into a myocardial infarction model improved cardiac repair by increasing angiogenesis. Mechanistically, MSChyp-sEVs promote HUVEC tube formation and migration by transferring miR-214 into recipient cells, inhibiting Sufu expression, and activating the hedgehog pathway. Hypoxia-induced vesicle modification is a feasible way to restore heart function after myocardial infarction.

Comparison of extracellular vesicle isolation processes for therapeutic applications

While extracellular vesicles (EVs) continue to gain interest for therapeutic applications, their clinical translation is limited by a lack of optimal isolation methods. We sought to determine how universally applied isolation methods impact EV purity and yield. EVs were isolated by ultracentrifugation (UC), polyethylene glycol precipitation, Total Exosome Isolation Reagent, an aqueous two-phase system with and without repeat washes or size exclusion chromatography (SEC). EV-like particles could be detected for all isolation methods but varied in their purity and relative expression of surface markers (Alix, Annexin A2, CD9, CD63 and CD81). Assessments of sample purity were dependent on the specificity of characterisation method applied, with total particle counts and particle to protein (PtP) ratios often not aligning with quantitative measures of tetraspanin surface markers obtained using high-resolution nano-flow cytometry. While SEC resulted in the isolation of fewer particles with a relatively low PtP ratio (1.12 × 107 ± 1.43 × 106 vs highest recorded; ATPS/R 2.01 × 108 ± 1.15 × 109, p ⩽ 0.05), EVs isolated using this method displayed a comparatively high level of tetraspanin positivity (e.g. ExoELISA CD63⁺ particles; 1.36 × 1011 ± 1.18 × 1010 vs ATPS/R 2.58 × 1010 ± 1.92 × 109, p ⩽ 0.001). Results originating from an accompanying survey designed to evaluate pragmatic considerations surrounding method implementation (e.g. scalability and cost) identified that SEC and UC were favoured for overall efficiency. However, reservations were highlighted in the scalability of these methods, which could potentially hinder downstream therapeutic applications. In conclusion, variations in sample purity and yield were evident between isolation methods, while standard non-specific assessments of sample purity did not align with advanced quantitative high-resolution analysis of EV surface markers. Reproducible and specific assessments of EV purity will be critical for informing therapeutic studies.

Abstract 2790: Exosomes as nanocarriers for biomolecules and potential diagnostic targets in cancer

Abstract Introduction: The tumor microenvironment is a dynamic domain and communication hub for signaling molecules, contributing to proliferative and metastatic behaviors observed in cancerous tissues. Intercellular interactions are commonly mediated through extracellular vesicles that carry vital information for growth and survival, a feature that is highly advantageous for cancer cells to hijack. Hepatocellular carcinoma (HCC) is one of the most rapidly increasing types of cancer in the United States. Often aggressive, HCC arises from the uncontrollable division of hepatocytes, which may disrupt the regular functions of the liver and other organs. Identifying biomarkers is essential to potentiate drug treatments while minimizing chances of metastasis, recurrence, and mortality. Highly proliferative cells are known to secrete exosomes containing tumor-enhancing biomolecules that contribute to cancerous progression. Thus, analyzing exosomal cargo in serum is especially attractive for early diagnostics, profiling, and therapeutic purposes. We have explored potential oncogenic lncRNAs and extracellular signaling proteins in HCC and conducted phenotypic studies to observe their mode of action. Methods: HCC cell lines were propagated in EMEM containing exosome-free FBS. Exosomes were harvested with ThermoFisher Total Exosome Isolation Reagent from cell culture media, then resuspended in PBS. Zetasizer was used to measure the sizes of harvested exosomes, and western blot analysis was used to confirm exosomal markers. UCA1 and MALAT1 were checked via RTPCR via exosomes spiked with bacterial RNA as the loading control. Bradford assays were performed on exosomes lysed with RIPA for quantifying cargo proteins. Exosomal POTE-2 was observed through western blot analysis, in addition to ELISAs to identify their presence in media. Phenotypic studies were performed using isolated exosomes. Results: The isolated exosomes were within the size range of 40-200nm, with a negative charge. The western blot of the exosomal markers confirmed their purity. RTPCR results showed LncRNAs MALAT1 and lncRNA UCA1 present in exosomes, whereas POTE-2 protein presence was confirmed with western blot. Phenotypic studies from the isolated exosomes are in progress. Conclusions: Exosomes in serum are easily accessible biomolecules making them functional, less invasive targets for profiling, diagnostics, and therapeutics via liquid biopsies. Exosome-mediated delivery of lncRNAs MALAT1 and UCA1 to primary CRC cells has been found to promote malignancy. We have verified their presence in exosomes secreted by metastatic cell lines, in addition to oncoprotein POTE-2, which hold numerous significances for our phenotypic studies. These findings reaffirm exosomes as essential contributors to disease pathogenesis and present them as promising targets for diagnostics and treatment. Citation Format: Adithya Anilkumar, Samantha Lopez, Sophia Leslie, Kyle Doxtater, Neeraj Chauhan, Bilal Hafeez, Murali Yallapu, Meena Jaggi, Subhash Chauhan, Manish Tripathi. Exosomes as nanocarriers for biomolecules and potential diagnostic targets in cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2790.

FC049: Nefecon® (Budesonide) is an Epigenetic Modifier in IGA Nephropathy

Abstract BACKGROUND AND AIMS In recent years, the dysregulated expression of microRNAs (miRs)—small molecules of noncoding RNA that epigenetically fine-tune post-transcriptional gene expression—has been increasingly implicated in the pathogenesis of IgA nephropathy (IgAN). Extracellular miRs, contained within extracellular vesicles such as exosomes and microvesicles, are thought to function as important intercellular and interorgan modes of communication in health and disease. In the current study, next-generation sequencing (NGS) and subsequent real-time quantitative polymerase chain reaction (RT-qPCR) validation were performed to identify serum miRs associated with a high risk of future kidney function decline in IgAN. We then went on to determine whether treatment with Nefecon® 16 mg/day for 9 months was capable of modifying the serum levels of miRs associated with high-risk IgAN. This study was supported by a grant from Calliditas Therapeutics AB. METHOD NGS was performed by Qiagen (Germany) on serum from patients with IgAN (10 at high risk and 10 at low risk of progression) or membranous nephropathy (MN, n=10), as well as healthy individuals (HS, n=10). Sequencing data were validated by RT-qPCR using TaqMan miR PCR assays in independent sets of serum samples (20 per cohort). Using the Total Exosome Isolation (from serum) reagent (Thermo Fisher Scientific, UK), extracellular exosomes were isolated from the serum of participants of the NEFIGAN trial from the placebo group (n=40) and Nefecon® 16 mg/day group (n=40) at the start of treatment (SOT) and end of treatment (EOT). RNA was isolated and levels of miRs-483-5p and -122-5p were measured by RT-qPCR. The NEFIGAN trial (NCT01738035) was a randomized, double-blind, placebo-controlled Phase 2b trial designed to assess the safety and efficacy of Nefecon® a novel targeted-release formulation of budesonide, designed to deliver the drug to the distal ileum in patients with IgAN. The trial comprised a 6-month run-in, a 9-month treatment and a 3-month follow-up phase. A total of 48 patients received Nefecon® 16 mg/day, 51 patients received Nefecon® 8 mg/day and 50 patients received placebo. The key result of the study was that Nefecon® 16 mg/day, added to optimized renin–angiotensin system blockade, reduced proteinuria and stabilized estimated glomerular filtration rate in patients with IgAN. These findings have now been replicated in the NefIgArd study, which released data in 2021. RESULTS miRs-483-5p and -122-5p were significantly overexpressed in the serum of patients with IgAN at high risk of progression compared with those who had stable IgAN or HS, but not compared with patients with MN. Both miRs were also found to be significantly increased in extracellular exosomes in high-risk IgAN compared with low-risk IgAN, HS and MN. Interestingly, levels of exosomal miRs-483-5p and -122-5p did not correlate with total serum IgA, IgA1, galactose-deficient IgA1 or IgA–IgG immune complex levels, suggesting a novel mechanism of action. Treatment with 16 mg/day of Nefecon® led to a significant reduction in the exosomal levels of miR-122-5p, while no change in miR-483-5p levels was observed in the treated group. CONCLUSION These data reveal a dysregulation of systemic exosomal miR expression in IgAN, and demonstrate for the first time that it is possible to pharmacologically modify the miR content of circulating exosomes in IgAN. Treatment with Nefecon® 16 mg/day for 9 months selectively downregulated exosomal miR-122-5p, while having no effect on exosomal miR-483-5p levels, arguing against a generalized ‘anti-miR’ effect of Nefecon®. Studies are ongoing to both precisely delineate the cellular source(s) of these exosomes and determine the downstream impact of these changes on glomerular and tubulointerstitial biology.

Characterizing Extracellular Vesicles and Particles Derived from Skeletal Muscle Myoblasts and Myotubes and the Effect of Acute Contractile Activity.

Extracellular vesicles (EVs), released from all cells, are essential to cellular communication and contain biomolecular cargo that can affect recipient cell function. Studies on the effects of contractile activity (exercise) on EVs usually rely on plasma/serum-based assessments, which contain EVs from many different cells. To specifically characterize skeletal muscle–derived vesicles and the effect of acute contractile activity, we used an in vitro model where C2C12 mouse myoblasts were differentiated to form myotubes. EVs were isolated from conditioned media from muscle cells at pre-differentiation (myoblasts) and post-differentiation (myotubes) and also from acutely stimulated myotubes (1 h @ 14 V, C-Pace EM, IonOptix, Westwood, MA, USA) using total exosome isolation reagent (TEI, ThermoFisher (Waltham, MA, USA), referred to as extracellular particles [EPs]) and differential ultracentrifugation (dUC; EVs). Myotube-EPs (~98 nm) were 41% smaller than myoblast-EPs (~167 nm, p < 0.001, n = 8–10). Two-way ANOVA showed a significant main effect for the size distribution of myotube vs. myoblast-EPs (p < 0.01, n = 10–13). In comparison, myoblast-EPs displayed a bimodal size distribution profile with peaks at <200 nm and 400–600, whereas myotube-Eps were largely 50–300 nm in size. Total protein yield from myotube-EPs was nearly 15-fold higher than from the myoblast-EPs, (p < 0.001 n = 6–9). Similar biophysical characteristics were observed when EVs were isolated using dUC: myotube-EVs (~195 nm) remained 41% smaller in average size than myoblast-EVs (~330 nm, p = 0.07, n = 4–6) and had comparable size distribution profiles to EPs isolated via TEI. Myotube-EVs also had 4.7-fold higher protein yield vs. myoblast EVs (p < 0.05, n = 4–6). Myotube-EPs exhibited significantly decreased expression of exosomal marker proteins TSG101, CD63, ALIX and CD81 compared with myoblast-EPs (p < 0.05, n = 7–12). Conversely, microvesicle marker ARF6 and lipoprotein marker APO-A1 were only found in the myotube-EPs (p < 0.05, n = 4–12). There was no effect of acute stimulation on myotube-EP biophysical characteristics (n = 7) or on the expression of TSG101, ARF6 or CD81 (n = 5–6). Myoblasts treated with control or acute stimulation–derived EPs (13 µg/well) for 48 h and 72 h showed no changes in mitochondrial mass (MitoTracker Red, ThermoFisher, Waltham, MA, USA), cell viability or cell count (n = 3–4). Myoblasts treated with EP-depleted media (72 h) exhibited ~90% lower cell counts (p < 0.01, n = 3). Our data show that EVs differed in size, distribution, protein yield and expression of subtype markers pre vs. post skeletal muscle–differentiation into myotubes. There was no effect of acute stimulation on biophysical profile or protein markers in EPs. Acute stimulation–derived EPs did not alter mitochondrial mass or cell count/viability. Further investigation into the effects of chronic contractile activity on the biophysical characteristics and cargo of skeletal muscle–specific EVs are warranted.

Exosomes carried miR-181c-5p alleviates neuropathic pain in CCI rat models.

Mesenchymal stem cells (MSCs) derived exosomes (Exos) are one of the most promising candidate for the treatment of this condition. However, the underlying molecular mechanism remains uncertain. Here we investigated the therapeutic effect of exosomal miR-181c-5p (ExomiR-181c-5p) on a rat model of neuropathic pain induced by sciatic nerve chronic constriction injury (CCI). In this study NP model was established using the CCI method. NP levels were assessed using PWT and PWL. Microarray analysis and RT-PCR were used to determine the relative expression of miR-181c-5p. MSC-derived exosomes were extracted using the total exosome isolation reagent characterized by WB and NTA. MiR-181c-5p was loading into Exos using electroporation. The inflammation response in microglia cells and CCI rats were assessed by ELISA assay respectively. Our study demonstrates that miR-181c-5p expression was obviously decreased in a time-dependent manner in CCI rats. MiR-181c-5p was effectively electroporated and highly detected in MSC-derived Exos. ExomiR-181c-5p internalized by microglia cells and inhibit the secretion of inflammation factors. ExomiR-181c-5p intrathecal administration alleviated neuropathic pain and neuroinflammation response in CCI rats. Taken together, ExomiR-181c-5p alleviated CCI-induced NP by inhibiting neuropathic inflammation. ExomiR-181c-5p may be a valid alternative for the treatment of neuropathic pain and has vast potential for future development.

Exosomes in serum‑free cultures of THP‑1 macrophages infected with Mycobacterium tuberculosis.

It has been shown from the isolation and characterization of exosomes from cell culture media supplemented with fetal bovine serum that both their quality and purity are affected. The high abundance of serum proteins, including bovine cell derived exosomes, is also a potential source of contaminants, which may result in appreciable yields of impure exosomes, thereby leading to artifacts. Isolation and characterization of exosomes from cells maintained under serum-free conditions should therefore ensure the high quality necessary for medical applications. To meet this end, the present study aimed to characterize exosomes released from THP-1 macrophages cultured in serum-free, ultra-centrifuged medium upon infection with the human pathogen Mycobacterium tuberculosis (Mtb). Macrophages differentiated from the human cell line THP-1 were infected at a multiplicity of infection (MOI) of 5. Macrophages were cultivated in CellGenix® GMP DC serum-free ultra-centrifuged medium for 4, 24 and 48 h at 37°C in a humidified atmosphere with 5% CO2. Total exosome isolation reagent was used to extract the exosomes from the cell culture supernatants of naïve and Mtb-infected THP-1 macrophages. The size and purity of the exosomes isolated were subsequently assessed by various methods, including nanoparticle tracking analysis, flow cytometry, MACSPlex exosome analysis, and western blotting. The serum-free, ultra-centrifuged medium was found to support the proliferation of the THP-1 cells successfully. The nanoparticle tracking analysis data revealed that the majority of the isolated particles were within the size range of exosomes (i.e., 30–150 nM). The MACSPlex exosome analysis confirmed the expression of the exosomal markers, CD9, CD63 and CD81. Furthermore, western blot analysis of the isolated exosomes indicated the presence of CD9, CD63, CD81 and lysosomal associated membrane protein-1 (LAMP-1), and also confirmed the absence of Mtb proteins. Taken together, these data provide evidence that serum-free, ultra-centrifuged CellGenix® GMP DC medium is suitable for application in exosome research, and may significantly advance such studies. Therefore, the use of serum-free medium for exosome isolation purposes could offer considerable advantages, and constitute a significant improvement in the growing field of extracellular vesicle research. The use of more sensitive methods represents an advance that will enable researchers to rule out the presence of Mtb pathogenic proteins in exosomes isolated from infected serum-free cell cultures.

Physical Activity as a Preventive Lifestyle Intervention Acts Through Specific Exosomal miRNA Species-Evidence From Human Short- and Long-Term Pilot Studies.

Exercise initiates systemic adaptation to promote health and prevent various lifestyle-related chronic diseases. Emerging evidence suggests that circulating exosomes mediate some of the beneficial effects of exercise via the transfer of microRNAs between tissues. Yet to date, a comprehensive profile of the exosomal miRNA (exomiR) content released following short-term (0.5 year in this study) and long-term (25 + years in this study) regular bouts of exercise is still lacking. However, a better understanding of these miRNA species would assist in clarifying the role of regular exercise at the molecular level in the prevention of chronic diseases. In the present pilot studies we analyzed serum exomiR expression in healthy young, sedentary participants (n = 14; age: 23 ± 2 years) at baseline and following a half year-long moderate-intensity regular exercise training. We also analyzed serum exomiR expression in older, healthy trained participants (seniors, n = 11; age: 62 ± 6 years) who engaged in endurance activities for at least 25 years. Following the isolation and enrichment of serum exosomes using Total Exosome Isolation Reagent (TEI) their exomiR levels were determined using the amplification-free Nanostring platform. Hierarchical cluster analysis revealed that the majority of exomiRs overlap for short-term (0.5 year in this study) and long-term (25 + years in this study) regular bouts of exercise. The top 12 significantly altered exomiRs (let-7a-5p; let-7g-5p; miR-130a-3p; miR-142-3p; miR-150-5p; miR-15a-5p; miR-15b-5p; miR-199a-3p; miR-199b-3p; miR-223-3p; miR-23a-3p, and miR-451a-3p) were used for further evaluation. According to KEGG pathway analysis a large portion of the exomiRs target chronic diseases including cancer, neurodegenerative and metabolic diseases, and viral infections. Our results provide evidence that exosomal miRNA modulation is the molecular mechanism through which regular exercise prevents various chronic diseases. The possibility of using such exomiRs to target diseases is of great interest. While further validation is needed, our comprehensive exomiR study presents, for the first time, the disease-preventive molecular pattern of both short and long-term regular exercise.

Exosomes Released From Human Bone Marrow-Derived Mesenchymal Stem Cell Attenuate Acute Graft-Versus-Host Disease After Allogeneic Hematopoietic Stem Cell Transplantation in Mice.

ObjectiveMesenchymal stromal cell–derived exosomes have been applied for the treatment of several immune diseases. This study aimed to explore the effect of human bone marrow–derived mesenchymal stem cell (hBMSC)–derived exosomes on acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (HSCT).MethodshBMSC were cultured, and the culture supernatants were then collected to prepare exosomes using total exosome isolation reagent from Invitrogen. Mouse aGVHD model was established by allogeneic cell transplantation and injected with hBMSC-derived exosomes (Msc-exo) via tail vein. Exosomes from human fibroblast (Fib-exo) were used as the treatment control. The effects of Msc-exo on dendritic cells, CD4+, and CD8+ T cells in aGVHD mice were analyzed through flow cytometry. The impact on inflammatory cytokines was tested by ELISA. Besides, the body weight, survival rate, and clinical score of treated mice were monitored.ResultsMsc-exo were successfully prepared. aGVHD mice injected with Msc-exo led to 7–8-fold increase of the CD8α+ conventional dendritic cells (cDCs) and CD11b+ cDCs compared with the controls. In addition, Msc-exo altered the T help and Treg subpopulation, and decreased the cytotoxicity and proliferation of cytotoxic T cells to favor inflammatory inhibition in aGVHD mice. Mice that received Msc-exo exhibited decreased weight loss and reduced aGVHD clinical score in a time-dependent manner as well as reduced lethality compared with Fib-exo treated or untreated control. Furthermore, the levels of IL-2, TNF-α, and IFN-γ were decreased, as well as the level of IL-10 was increased after Msc-exo treatment in vivo and in vitro.ConclusionhBMSC-derived exosomes could attenuate aGVHD damage and promote the survival of aGVHD mice by regulating the DC and T-cell subpopulation and function, and lead to inhibited inflammatory response in aGVHD mice.

A comparison of exosome purification methods using serum of Marek's disease virus (MDV)-vaccinated and -tumor-bearing chickens

Marek's disease (MD) is an alphaherpesvirus (Marek's disease virus, MDV)-induced pathology of chickens associated with paralysis, immunosuppression, neurological signs, and T-cell lymphomas. MD is controlled in poultry production via live attenuated vaccines. The purpose of the current study was to compare methods for precipitating exosomes from vaccinated and protected chicken sera (VEX) and tumor-bearing chicken sera (TEX) for biomarker analysis of vaccine-induced protection and MD lymphomas respectively. A standard polyethylene glycol (PEG, 8%) method was compared to a commercial reagent (total exosome isolation reagent, TEI) for exosome yield and RNA content. Although exosomes purified by PEG or TEI were comparable in size and morphology, TEI-reagent yielded 3-4-fold greater concentration. Relative expression of 8 out of 10 G. gallus- and MDV1-encoded miRNAs examined displayed significant difference depending upon the precipitation method used. Standard PEG yields comparable, albeit lower amounts of exosomes than the TEI-reagent and a distinctive miRNA composition.

Exosomes isolated from two different cell lines using three different isolation techniques show variation in physical and molecular characteristics

Exosomes are the nanoscopic lipid bi-layered extracellular vesicles with the potential to be utilized as targeted therapeutics. In our investigation, we compared three major exosome isolation techniques that were Total Exosome Isolation reagent (TEI), Protein organic solvent precipitation (PROSPR) and differential ultracentrifugation (UC) based on the biophysical and physicochemical characteristics of exosomes isolated from COLO 205 and MCF-7 cancer cell's conditioned media with an aim to select a suitable method for translational studies. 3D image analysis and particle size distribution of exosomes from their HRTEM images depicted the morphological differences. Molecular and analytical characterization of exosomes using western blotting, Raman and ATR-FTIR spectroscopy and the multivariate analysis on the spectral data obtained, assessed for better molecular specifications and purity of particle. TEI method isolated exosomes with higher exosomal yield, purity, and recovery directly translatable into drug delivery and targeted therapeutics whereas ultracentrifuge had good recovery of particle morphology but showed particle aggregation and yielded exosomes with smaller mean size. PROSPR technique isolated a mixture of EVs, showed lower protein recovery in PAGE and western blotting but higher spectroscopic protein to lipid ratio and distinguishable EV population in multivariate analysis compared to exosomes isolated by TEI and UC. This comparative study should help in choosing a specific exosome isolation technique required for the objective of downstream applications.

Exosome Production and Regenerative Potential is Influenced by Mechanical Stimulus and Cell Origin

INTRODUCTIONExosomes are nanosized membrane bound vesicles (30–150 nm) secreted by cells. Exosomes contain nucleic acids and proteins used to signal and influence the cells around them. It has been shown that mesenchymal stem cells (MSCs) influence tissue regeneration and healing through their paracrine secretion of pro‐regenerative factors. Many of these factors are contained within exosomes suggesting that exosome suspensions may be an effective cell‐free therapy for tissue regeneration and repair. Previously, our group has found that mechanical stimulus can be used to rescue muscle derived stem cells from an aged mouse model (progeria mice), indicating that physical environment influences MSC function. With this knowledge, we hypothesized that myoblasts subjected to mechanical stimulation would improve exosome quantity and function. Given the fact that several studies have also shown muscle to bone cross talk improves fracture repair, we further hypothesized that optimized myoblast exosomes could improve osteoblast cell function.METHODSC2C12 myoblasts were cultured using the FlexCell FX‐5000TT bioreactor. Two exercise regimens were programmed using biaxial or uniaxial strain: 1) low intensity regimen (LIR) (0–15% strain at 0.5 Hz for 24 hours) 2) high intensity interval regimen (HIIR) (12–22% strain at 1 Hz for 10 minutes followed by 50 minutes of rest repeated for 24 hours). Unexercised, control cells were cultured in parallel. MC3T3‐E1 osteoblasts were cultured for 24 hours for exosome collection. Exosomes were isolated using Invitrogen Total Exosome Isolation Reagent. System Bioscience’s ExoELISA‐ULTRA CD81 Kit and a BCA assay were used to quantify exosome number and protein concentration. 20 ug of exosomes (~5e9 exosomes) were used for treatment in proliferation and differentiation assays. Proliferation was assessed using PrestoBlue (Thermo Fisher). Myogenic differentiation was evaluated using image analysis (15 images per group).ResultsAll exercise regimens resulted in increased exosome concentrations in myoblasts. Biaxial strain and HIIR resulted in the greatest exosome production. Further, we found increased functionality of exosomes from exercised cells resulting in greater proliferation and differentiation of myoblasts. Interestingly, myoblast exosomes also significantly increased proliferation in osteoblast cells. However, in contrast, exosomes isolated from osteoblasts significantly decreased proliferation when treated on myoblasts but significantly increased proliferation when treated back upon themselves.DISCUSSION and CONCLUSIONOur results indicate that mechanical stimulus and cell origin directly influence exosome production. We found that exercise can be optimized to improve the production and regenerative capacity of myoblast exosomes. Further, we found a positive effect of myoblast exosomes on osteoblasts, but the converse, osteoblast exosomes on myoblasts, had a negative effect on cell proliferation. Coupling this with findings to indicate exosomes remain stable at −80° C for at least 4 months, we see exosomes as a potential cell‐free therapy for tissue regeneration following musculoskeletal traumas.Support or Funding InformationBorgen Family Foundation(A) Myoblast Cells secrete more exosomes when exercised (flex) compared to non‐exercised (static) cells. (* = p &lt; 0.05, n = 8) (B) Exercise protocol attenuates exosome production. (**** = p &lt; 0.0001, n = 4) (C–F) Exosomes from exercised cells increase myogenic differentiation. (* = p &lt; 0.05, *** = p &lt; 0.001, n = 4)Figure 1(A) Exosomes from exercised cells increase proliferation. (* = p &lt; 0.05, *** = p &lt; 0.001, n = 4) (B) Exosomes effect on proliferation is dependent on cell origin. (*** = p &lt; 0.001, n = 3)Figure 2

Differential exosome miRNA expression in oral cancer stem cells

BackgroundOral squamous cell carcinomas (OSCC) secrete exosomes into the surrounding extracellular environment to promote the horizontal transfer of bioactive molecules including microRNA (miRNA). The primary objective of this study was to explore potential differences in miRNA content between OSCC and OSCC stem cells.MethodsThe OSCC cell lines SCC4, SCC15, SCC25 and CAL27 were used in these studies. The corresponding OSCC stem cells that demonstrated phenotypic adhesion independent tumor spheres (AiTS) were manually isolated. All cells were cultured in DMEM containing 10% exosome-free fetal bovine serum. Exosomes were isolated using Total Exosome Isolation reagent (Invitrogen) and RNA was purified using Total Exosome RNA isolation kit (Invitrogen). Exosome miRNA content was evaluated using miRNA Advanced Taqman Assays for miR-21, − 155, − 133, − 34, − 31, − 32, and − 365. The fold change of miRNA content was calculated using the comparative CT (ΔΔCT) method using miR-16 as an endogenous control.ResultsAfter successful cell cultures were established, AiTS (cancer stem cells) were manually separated and confirmed using CD133 and Sox-2 biomarkers. Exosomes and extracellular vesicles were successfully isolated from all cell lines and AiTS isolates for miRNA screening. All isolates exhibited miR-16 expression (positive control), but none contained mir-31, − 32, or 133a. Differential expression of miR-21, miR-34 and miR-155 were observed with patterns observed among the cancer cell lines which were distinct from the corresponding AiTS isolates.ConclusionsExosomes isolated from these different OSCC stem cell populations displayed nearly consistent downregulation/loss of miR-21 and miR-34 suggesting the possibility of a unique miRNA profile characteristic of oral cancer stem cells. These findings highlight the need to investigate the comprehensive functions of miR-21 and miR-34 in tumor progression and continued research to refine a miRNA profile that could aid in distinguishing tumors with poor prognosis.

Mesenchymal stem cell-derived exosomes ameliorate cardiomyocyte apoptosis in hypoxic conditions through microRNA144 by targeting the PTEN/AKT pathway

BackgroundA growing body of evidence suggests that stem cell-derived exosomal microRNAs (miRNAs) could be a promising cardioprotective therapy in the context of hypoxic conditions. The present study aims to explore how miRNA-144 (miR-144), a miRNA contained in bone marrow mesenchymal stem cell (MSC)-derived exosomes, exerts a cardioprotective effect on cardiomyocyte apoptosis in the context of hypoxic conditions and identify the underlying mechanisms.MethodsMSCs were cultured using the whole bone marrow adherent method. MSC-derived exosomes were isolated using the total exosome isolation reagent and confirmed by nanoparticle trafficking analysis as well as western blotting using TSG101 and CD63 as markers. The hypoxic growth conditions for the H9C2 cells were established using the AnaeroPack method. Treatment conditions tested included H9C2 cells pre-incubated with exosomes, transfected with miR-144 mimics or inhibitor, or treated with the PTEN inhibitor SF1670, all under hypoxic growth conditions. Cell apoptosis was determined by flow cytometry using 7-ADD and Annexin V together. The expression levels of the miRNAs were detected by real-time PCR, and the expression levels of AKT/p-AKT, Bcl-2, caspase-3, HIF-1α, PTEN, and Rac-1 were measured by both real-time PCR and western blotting.ResultsExosomes were readily internalized by H9C2 cells after co-incubation for 12 h. Exosome-mediated protection of H9C2 cells from apoptosis was accompanied by increasing levels of p-AKT. MiR-144 was found to be highly enriched in MSC-derived exosomes. Transfection of cells with a miR-144 inhibitor weakened exosome-mediated protection from apoptosis. Furthermore, treatment of cells grown in hypoxic conditions with miR-144 mimics resulted in decreased PTEN expression, increased p-AKT expression, and prevented H9C2 cell apoptosis, whereas treatment with a miR-144 inhibitor resulted in increased PTEN expression, decreased p-AKT expression, and enhanced H9C2 cell apoptosis in hypoxic conditions. We also validated that PTEN was a target of miR-144 by using luciferase reporter assay. Additionally, cells treated with SF1670, a PTEN-specific inhibitor, resulted in increased p-AKT expression and decreased H9C2 cell apoptosis.ConclusionsThese findings demonstrate that MSC-derived exosomes inhibit cell apoptotic injury in hypoxic conditions by delivering miR-144 to cells, where it targets the PTEN/AKT pathway. MSC-derived exosomes could be a promising therapeutic vehicle to facilitate delivery of miRNA therapies to ameliorate ischemic conditions.

Exosomes Derived From Mesenchymal Stem Cells Ameliorate Renal Ischemic-Reperfusion Injury Through Inhibiting Inflammation and Cell Apoptosis.

This study aimed to investigate the underlying mechanism of mesenchymal stem cells (MSCs) on protection of renal ischemia reperfusion injury (IRI). Exosomes originated from MSCs (MSC-ex) were extracted according to the instructions of Total Exosome Isolation Reagent. Rats were divided into five groups: sham-operated, IRI, MSC, MSC-ex, and MSC-ex + RNAase group. MSCs or MSC-ex were injected via carotid artery. The renal function test and pathological detection were applied to determine the renoprotection of MSC-ex on IRI. Western blotting and quantitative reverse transcription polymerase chain reaction (RT-qPCR) were conducted to examine the levels of apoptosis-related proteins and inflammatory cytokines. Our results revealed that MSC-derived exosomes attenuated renal dysfunction, histologic damage, and decreased apoptosis. The expression levels of inflammatory cytokines, such as interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), nuclear factor kappa B (NF-κB), and interferon gamma (IFN-γ), were decreased by the MSC-ex treatment. The expression levels of caspase-9, cleaved caspase-3, Bax, and Bcl-2 caused by IR were also inhibited by MSC-ex. MSC-ex + RNAase group shared the similar pattern of changes with IRI group, likely due to the ability of RNA hydrolase to eliminate the function of exosomes. Our results demonstrated that exosomes originating from MSCs have protective effects on IRI via inhibiting cell apoptosis and inflammatory responses. Out findings may provide a new insight into therapeutic mechanism of MSCs on renal IRI.

Morphometric Characterization of Extracellular Vesicles and Their Contents of miRNA-145 in Adults with and Without Obesity (P18-127-19)

ObjectivesThe aim was to characterize populations of extracellular vesicles (EVs) and their content of miRNA-145, in adults with obesity and normal weight. MethodsStudy design was cross-sectional and subjects were assigned to: group A (n = 10) which included participants with obesity (Body Mass Index (BMI) > 30 kg/m2), and group B (n = 10) included subjects with normal weight (BMI 18 - < 25 kg/m2). Subjects were free of co-morbidities. Weight, height, electrical bioimpedance, and serum lipids were evaluated. EVs were isolated from blood plasma using Invitrogen total exosome isolation reagent. Isolation was later corroborated by detecting the expression of the marker ALIX, an EV-associated protein by Western blot (WB), and the particle size was assessed using Zetasizer Nano ZS. The isolated EVs were also analyzed by transmission electron microscopy (TEM) and, finally, the expression of miRNA-145 was determined in the EVs by real-time PCR. ResultsWe identified two sizes of EVs, that were later classified as exosomes and microvesicles. The characterization of EVs was confirmed with the expression of ALIX and the images of TEM. In subjects from group A, EVs size (65.9 ± 16.1 nm) was larger than in those subjects without obesity (42.3 ± 10.7 nm), but this was not statistically significant. Body weight and tryglycerides concentration were positively associated (P < 0.05) with EVs’ size. The variability in the size of EVs between groups could reflect different composition or maturation level of EVs. Analysis of miRNA-145 content in the EVs, showed that it was 1.15 times higher in group A vs B, and therefore it was possible to identify a differential expression associated with higher levels of risk for subjects with obesity compared to the normal weight group. ConclusionsThe size of EVs is related with state of obesity, also its content could reflect higher risk of developing comorbidities associated with excess weight and nutritional status. Funding SourcesThe project was funded by CIAD and MAH received a scholarship from CONACYT.

Differential MicroRNA Expression of miR-21 and miR-155 within Oral Cancer Extracellular Vesicles in Response to Melatonin.

Objective: Extracellular vesicles derived from oral cancer cells, which include Exosomes and Oncosomes, are membranous vesicles secreted into the surrounding extracellular environment. These extracellular vesicles can regulate and modulate oral squamous cell carcinoma (OSCC) progression through the horizontal transfer of bioactive molecules including proteins, lipids and microRNA (miRNA). The primary objective of this study was to examine the potential to isolate and evaluate extracellular vesicles (including exosomes) from various oral cancer cell lines and to explore potential differences in miRNA content. Methods: The OSCC cell lines SCC9, SCC25 and CAL27 were cultured in DMEM containing 10% exosome-free fetal bovine serum. Cell-culture conditioned media was collected for exosome and extracellular vesicle isolation after 72 h. Isolation was completed using the Total Exosome Isolation reagent (Invitrogen) and extracellular vesicle RNA was purified using the Total Exosome RNA isolation kit (Invitrogen). Extracellular vesicle miRNA content was evaluated using primers specific for miR-16, -21, -133a and -155. Results: Extracellular vesicles were successfully isolated from all three OSCC cell lines and total extracellular vesicle RNA was isolated. Molecular screening using primers specific for several miRNA revealed differential baseline expression among the different cell lines. The addition of melatonin significantly reduced the expression of miR-155 in all of the OSCC extracellular vesicles. However, miR-21 was significantly increased in each of the three OSCC isolates. No significant changes in miR-133a expression were observed under melatonin administration. Conclusions: Although many studies have documented changes in gene expression among various cancers under melatonin administration, few studies have evaluated these effects on microRNAs. These results may be among the first to evaluate the effects of melatonin on microRNA expression in oral cancers, which suggests the differential modulation of specific microRNAs, such as miR-21, miR-133a and miR-155, may be of significant importance when evaluating the mechanisms and pathways involved in melatonin-associated anti-tumor effects.

Bone marrow mesenchymal stem cell-derived exosomes alleviate high phosphorus-induced vascular smooth muscle cells calcification by modifying microRNA profiles.

Vascular calcification is a common complication in patients with chronic kidney disease (CKD). It is an important predictor of cardiovascular disease and all-cause mortality. Previous studies have confirmed that bone marrow mesenchymal stem cell (BMSC) therapy can reduce vascular calcification, but the specific mechanism is still controversial. In this study, we aimed to investigate the mechanisms of BMSC-derived exosomes (EXO) in improving vascular calcification. BMSCs were cultured and EXO were isolated using the Total Exosome Isolation Reagent. Human aortic vascular smooth muscle cells (HA-VSMCs) were cultured into three groups: control group, high phosphorus group, and high phosphorus plus EXO group. Then, indicators related to smooth muscle cell calcification and microRNA profiles were analyzed. BMSC-derived exosomes inhibited high phosphorus-induced calcification in HA-VSMCs. Besides, EXO treatment reduced calcium content and decreased the alkaline phosphatase (AKP) activity in high phosphorus co-incubated HA-VSMCs. MicroRNA (miRNA) and mRNA expression profiles analyses revealed that 63 miRNAs were significantly upregulated and 1424 genes were significantly downregulated in HA-VSMCs after EXO treatment. Functional miRNA-gene regulatory network revealed that mTOR, MAPK, and Wnt signaling pathway were involved in vascular calcification. BMSC-derived exosomes alleviated high phosphorus-induced calcification in HA-VSMC through modifying miRNA profiles.

The Regenerative Potential of Amniotic Fluid Stem Cell Extracellular Vesicles: Lessons Learned by Comparing Different Isolation Techniques

Extracellular vesicles (EVs) derived from amniotic fluid stem cells (AFSCs) mediate anti-apoptotic, pro-angiogenic, and immune-modulatory effects in multiple disease models, such as skeletal muscle atrophy and Alport syndrome. A source of potential variability in EV biological functions is how EV are isolated from parent cells. Currently, a comparative study of different EV isolation strategies using conditioned medium from AFSCs is lacking. Herein, we examined different isolation strategies for AFSC-EVs, using common techniques based on differential sedimentation (ultracentrifugation), solubility (ExoQuick, Total Exosome Isolation Reagent, Exo-PREP), or size-exclusion chromatography (qEV). All techniques isolated AFSC-EVs with typical EV morphology and protein markers. In contrast, AFSC-EV size, protein content, and yield varied depending on the method of isolation. When equal volumes of the different AFSC-EV preparations were used as treatment in a model of lung epithelial injury, we observed a significant variation in how AFSC-EVs were able to protect against cell death. AFSC-EV enhancement of cell survival appeared to be dose dependent, and largely uninfluenced by variation in EV-size distributions, relative EV-purity, or their total protein content. The variation in EV-mediated cell survival obtained with different isolation strategies emphasizes the importance of testing alternative isolation techniques in order to maximize EV regenerative capacity.