Therapeutic Effects Of Exosomes Research Articles

Cardiac tissue model of immune-induced dysfunction reveals the role of free mitochondrial DNA and the therapeutic effects of exosomes.

Despite tremendous progress in the development of mature heart-on-a-chip models, human cell-based models of myocardial inflammation are lacking. Here, we bioengineered a vascularized heart-on-a-chip with circulating immune cells to model severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced acute myocarditis. We observed hallmarks of coronavirus disease (COVID-19)-induced myocardial inflammation, as the presence of immune cells augmented the secretion of proinflammatory cytokines, triggered progressive impairment of contractile function, and altered intracellular calcium transients. An elevation of circulating cell-free mitochondrial DNA (ccf-mtDNA) was measured first in the heart-on-a-chip and then validated in COVID-19 patients with low left ventricular ejection fraction, demonstrating that mitochondrial damage is an important pathophysiological hallmark of inflammation-induced cardiac dysfunction. Leveraging this platform in the context of SARS-CoV-2-induced myocardial inflammation, we established that administration of endothelial cell-derived exosomes effectively rescued the contractile deficit, normalized calcium handling, elevated the contraction force, and reduced the ccf-mtDNA and cytokine release via Toll-like receptor-nuclear factor κB signaling axis.

Exosomes Derived from Schistosoma japonicum Cystatin-Treated Macrophages Attenuated CLP-Induced Sepsis in Mice

Sepsis is a disease caused by multiple microbial infections resulting in multiple organ failure. Schistosoma japonicum secreted cystatin (Sj-Cys) is a strong immunomodulator that stimulates M2 macrophages and alleviates inflammatory damage caused by sepsis. To determine whether the therapeutic effect of Sj-Cys on sepsis can be conveyed by the exosomes released by Sj-Cys-stimulated macrophages, RAW264.7 macrophages were stimulated with rSj-Cys in vitro, the exosomes were obtained from the cell culture supernatant by ultracentrifugation. Sepsis was induced in BALB/c mice by cecal ligation and puncture (CLP). The septic mice were treated with exosomes derived from Sj-Cys-treated macrophages. The treatment effect of exosomes on sepsis was assessed by examining the survival rate of mice up to 72 hr and measuring serum levels of inflammatory cytokines, liver/kidney damage biomarkers, and observing pathological changes in tissue sections. The tissue levels of M1, M2 macrophage surface markers, and TRL2/MyD88 were measured to explore possible mechanisms. Results. Exosomes derived from Sj-Cys-treated macrophages exhibited significant therapeutic effect on CLP-induced sepsis in mice with prolonged survival rate and less damage of critical organs by downregulating the proinflammatory factors TNF-α and IL-6 and upregulating the anti-inflammatory factor TGF-β. The therapeutic effect of exosomes is associated with macrophage polarization from M1 to M2 in the infected tissues via downregulating TRL2/MyD88 inflammatory pathway. Conclusions. Exosomes derived from Sj-Cys-treated macrophages attenuated sepsis in mice through promoting macrophage polarization from M1 to M2 and reducing inflammatory responses, possibly via downregulating TLR2/MyD88 inflammatory signaling pathway. This offers new approaches for immunotherapy of sepsis.

Human Placental Mesenchymal Stem Cells-Exosomes Alleviate Endothelial Barrier Dysfunction via Cytoskeletal Remodeling through hsa-miR-148a-3p/ROCK1 Pathway.

Endothelial barrier disruption of human pulmonary vascular endothelial cells (HPVECs) is an important pathogenic factor for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Mesenchymal stem cells-exosome (MSCs-Exo) represents an ideal carrier for cell-free therapy. The therapeutic implication and underlying mechanism of human placental MSCs-Exo (HPMSCs-Exo) in ALI/ARDS need to be further explored. HPMSCs-Exo was extracted from HPMSCs and characterized. Then, the therapeutic effects of exosomes were evaluated in ALI mice and HPVECs. RNA-sequencing was applied to reveal the miRNA profile of HPMSCs-Exo and differentially expressed genes (DEGs) in HPMSCs-Exo-pretreated HPVECs. The targets of miRNAs were predicted by bioinformatics methods and correlated to DEGs. Finally, the role of hsa-miR-148a-3p/ROCK1 pathway in HPVECs has been further discussed. The results showed that HPMSCs-Exo could downregulate Rho-associated coiled-coil-containing protein kinase 1 (ROCK1), upregulate the expression of zonula occludens-1 (ZO-1) and F-actin, promote HPVECs migration and tube formation, reduce cytoskeletal disorders and cell permeability, and thus improve ALI/ARDS. RNA-sequencing revealed the DEGs were mainly enriched in cell junction, angiogenesis, inflammation, and energy metabolism. HPMSCs-Exo contains multiple miRNAs which are associated with cytoskeletal function; the expression abundance of hsa-miR-148a-3p is the highest. Bioinformatic analysis identified ROCK1 as a target of hsa-miR-148a-3p. The overexpression of hsa-miR-148a-3p in HPMSCs-Exo promoted the migration and tube formation of HPVECs and reduced ROCK1 expression. However, the overexpression of ROCK1 on HPVECs reduced the therapeutic effect of HPMSCs-Exo. HPMSCs-Exo represents a protective regimen against endothelial barrier disruption of HPVECs in ALI/ARDS, and the hsa-miR-148a-3p/ROCK1 pathway plays an important role in this therapeutics implication.

The therapeutic effects of exosomes the first time isolated from pancreatic islet-derived progenitor cells in the treatment of pancreatic cancer.

Insulinoma is an excessive insulin-released beta cell tumor. Pancreas cancer is one of the deadliest malignant neoplasms. Exosomes are secreted cell membrane vesicles containing a large number of proteins, lipids, and nucleic acids. The aim of this study is to investigate the effects of exosomes on two cell lines of benign and malignant character. For the first time, exosomes were isolated from pancreatic island-derived progenitor cells (PID-PCs) and applied to INS-1 and MiaPaCa-2 cells. In addition, exosomes isolated from PID-PC, MiaPaca-2, and INS-1 cells were characterized in order to compare their sizes with other previously isolated exosomes. Alix, TSG101, CD9, and CD81 were analyzed. The size and concentration of exosomes and the cell viability were detected. The cells were marked with HSP90, HSF-1, Kaspaz-8, Active-Kaspaz-3, Beclin, and p-Bcl-2. The cell cytotoxicity and insulin levels kit were measured. Alix in all exosomes, and PID-PC, MiaPaca-2 cell lysates; TSG101 in PID-PC and MiaPaca-2 cell lysates; CD9 in INS-1 exosomes were detected. The dimensions of isolated exosomes were 103.6 ± 28.6nm, 100.7 ± 10nm, and 147.2 ± 12.3nm for PID-PCs, MiaPaca-2, and INS-1 cells. The cell viability decreased and HSP90 increased in the MiaPaca-2 cells. The HSF-1 was higher in the control MiaPaca-2 cell compared to the control INS-1 cell, and the exosome-treated MiaPaca-2 cell compared to the exosome-treated INS-1 cell. Beclin and p-Bcl-2 were decreased in the exosome-treated MiaPaca-2 cells. The insulin level in the cell lysates increased compared to cell secretion in INS-1 cells. In conclusion, exosomes isolated from the PID-PC caused cell death in the MiaPaca-2 cells in a time- and dose-dependent manner. The IC50 value determined for MiaPaca-2 cells has no effect on cell viability in INS-1 cells, which best mimics pancreatic beta cells and can be used instead of healthy pancreatic beta cells. Isolated exosomes can kill cancer cells without damaging healthy cells.

Recent Advances of Using Exosomes as Diagnostic Markers and Targeting Carriers for Cardiovascular Disease.

Cardiovascular diseases (CVDs) are the leading cause of human death worldwide. Exosomes act as endogenous biological vectors; they possess advantages of low immunogenicity and low safety risks, also providing tissue selectivity, including the inherent targeting the to heart. Therefore, exosomes not only have been applied as biomarkers for diagnosis and therapeutic outcome confirmation but also showed potential as drug carriers for cardiovascular targeting delivery. This review aims to summarize the progress and challenges of exosomes as novel biomarkers, especially many novel exosomal noncoding RNAs (ncRNAs), and also provides an overview of the improved targeting functions of exosomes by unique engineered approaches, the latest developed administration methods, and the therapeutic effects of exosomes used as the biocarriers of medications for cardiovascular disease treatment. Also, the possible therapeutic mechanisms and the potentials for transferring exosomes to the clinic for CVD treatment are discussed. The advances, in vivo and in vitro applications, modifications, mechanisms, and challenges summarized in this review will provide a general understanding of this promising strategy for CVD treatment.

Various Three-Dimensional Culture Methods and Cell Types for Exosome Production.

Cell-based therapies have been used as promising treatments for several untreatable diseases. However, cell-based therapies have side effects such as tumorigenesis and immune responses. To overcome these side effects, therapeutic effects of exosomes have been researched as replacements for cell-based therapies. In addition, exosomes reduced the risk that can be induced by cell-based therapies. Exosomes contain biomolecules such as proteins, lipids, and nucleic acids that play an essential role in cell-cell and cell-matrix interactions during biological processes. Since the introduction of exosomes, those have been proven perpetually as one of the most effective and therapeutic methods for incurable diseases. Much research has been conducted to enhance the properties of exosomes, including immune regulation, tissue repair, and regeneration. However, yield rate of exosomes is the critical obstacle that should be overcome for practical cell-free therapy. Three-dimensional (3D) culture methods are introduced as a breakthrough to get higher production yields of exosomes. For example, hanging drop and microwell were well known 3D culture methods and easy to use without invasiveness. However, these methods have limitation in mass production of exosomes. Therefore, a scaffold, spinner flask, and fiber bioreactor were introduced for mass production of exosomes isolated from various cell types. Furthermore, exosomes treatments derived from 3D cultured cells showed enhanced cell proliferation, angiogenesis, and immunosuppressive properties. This review provides therapeutic applications of exosomes using 3D culture methods.

Exosomes from hypoxia-pretreated adipose-derived stem cells attenuate ultraviolet light-induced skin injury via delivery of circ-Ash1l.

An increasing number of studies have reported that exosomes from adipose-derived stem cells (ADSCs) have antioxidant and anti-inflammatory properties. In the present study, we aimed at elucidating the potential therapeutic mechanism underlying ADSC exosomes in ultraviolet B-light (UVB)-induced skin injury. We isolated the exosomes from ADSCs and hypoxia-pretreated ADSCs. High-throughput sequencing was applied to identify differential circRNA expression. Then, a UV-induced murine skin injury model was constructed and the therapeutic effect of exosomes was determined using immunofluorescence and ELISA. The regulatory mechanism was demonstrated using luciferase reporter analysis and an in vitro experiment. Exosomes from hypoxia-pretreated ADSCs inhibited UVB light-induced vascular injury by reversing ROS and inflammatory factor expression. High-throughput sequencing showed that exosomes from hypoxia-pretreated ADSCs (HExo) improved UV-induced skin damage via delivery of circ-Ash1l. Downregulation of circ-Ash1l inhibited the therapeutic effect of HExo on UV-induced skin damage. It was further shown that GPX4 and miR-700-5p were circ-Ash1l downstream targets. MiR-700-5p overexpression or GPX4 downregulation inhibited the circ-Ash1l protective effects of UV-induced endothelial progenitor cell (EPC) damage. Thus, exosomes from hypoxia-pretreated ADSCs attenuated UV light-induced skin injury via circ-Ash1l delivery and ferroptosis inhibition.

Mesenchymal stem cell-derived exosome-educated macrophages alleviate systemic lupus erythematosus by promoting efferocytosis and recruitment of IL-17+ regulatory T cell

BackgroundAnti-inflammatory polarized macrophages are reported to alleviate systemic lupus erythematosus (SLE). Our previous studies have demonstrated that exosomes from adipose-derived stem cells promote the anti-inflammatory polarization of macrophages. However, the possible therapeutic effect of exosomes from stem cells on SLE remains unexplored.MethodsExosomes were isolated from the conditioned medium of bone marrow-derived mesenchymal stem cells using ultrafiltration and size-exclusion chromatography and were identified by nanoparticle tracking analysis and immunoblotting of exosomal-specific markers. Macrophages were collected from the MRL/lpr mouse kidney. The phenotype of macrophages was identified by immunoblotting for intracellular markers-inducible nitric oxide synthase (iNOS) and arginase-1 (Arg-1), and flow cytometry for macrophage markers F4/80, CD86, CD206, B7H4, and CD138. Pristane-induced murine lupus nephritis models were employed for in vivo study.ResultsWhen macrophages from the kidney of the MRL/lpr mice were treated with exosomes from bone marrow-derived mesenchymal stem cells (BM-MSCs), the upregulation of CD206, B7H4, CD138, Arg-1, CCL20, and anti-inflammatory cytokines was observed, which suggested that the macrophages were polarized to a specific anti-inflammatory phenotype. These anti-inflammatory macrophages produced low levels of reactive oxygen species (ROS) but had a high efferocytosis activity and promoted regulatory T (Treg) cell recruitment. Moreover, exosome injection stimulated the anti-inflammatory polarization of macrophages and increased the production of IL-17+ Treg cells in a pristane-induced murine lupus nephritis model. We observed that exosomes from BMMSCs depleted of microRNA-16 (miR-16) and microRNA-21 (miR-21) failed to downregulate PDCD4 and PTEN in macrophages, respectively, and attenuated exosome-induced anti-inflammatory polarization.ConclusionOur findings provide evidence that exosomes from BMMSCs promote the anti-inflammatory polarization of macrophages. These macrophages alleviate SLE nephritis in lupus mice by consuming apoptotic debris and inducing the recruitment of Treg cells. We identify that exosomal delivery of miR-16 and miR-21 is a significant contributor to the polarization of macrophages.Graphical abstract

Wound Healing Properties of Exosomes - A Review and Modelling of Combinatorial Analysis Strategies.

Wound healing is an elaborated process, well-regulated via cell migration and proliferation. Although the physiological basics of wound healing have been thoroughly investigated and reported, much remains to be studied. Particularly, various studies have demonstrated the immunomodulatory roles of exosomes derived from plant cells, mammalian cells, and mesenchymal stem cells (MSCs) in the healing and repairing system. The paracrine and therapeutic effects of exosomes are mainly associated with the broad exosomal cargo content comprising growth factors, cytokines, enzymes, nucleic acids, proteins, and lipid signaling molecules. Nevertheless, the functional or mechanism pathway of exosomes with reference to overall exosomal cargo remains undetermined. To date, combinatorial analysis strategies employing Database for Annotation, Visualization, and Integrated Discovery (DAVID), STRING tools, Gene Ontology (GO), Kyoto Encyclopedia of Genes, Genomes (KEGG) pathway enrichment analysis, as well as Ingenuity Pathway Analysis (IPA) have been applied in elucidating network interaction and functional pathway of exosomes. In this review paper, the application of combinatorial analysis strategies is demonstrated to better understand the therapeutic potentials of exosomes in the wound healing process. In conclusion, functional modulation of exosomal cargo for specific biological treatment is achievable, and modelling of combinatorial analysis strategies will hopefully bridge the research gap and provide a paradigm shift to regenerative processes.

The Application Potential and Advance of Mesenchymal Stem Cell-Derived Exosomes in Myocardial Infarction.

Myocardial infarction (MI) is a devastating disease with high morbidity and mortality caused by the irreversible loss of functional cardiomyocytes and heart failure (HF) due to the restricted blood supply. Mesenchymal stem cells (MSCs) have been emerging as lead candidates to treat MI and subsequent HF mainly through secreting multitudinous factors of which exosomes act as the most effective constituent to boost the repair of heart function through carrying noncoding RNAs and proteins. Given the advantages of higher stability in the circulation, lower toxicity, and controllable transplantation dosage, exosomes have been described as a wonderful and promising cell-free treatment method in cardiovascular disease. Nowadays, MSC-derived exosomes have been proposed as a promising therapeutic approach to improve cardiac function and reverse heart remodeling. However, exosomes' lack of modification cannot result in desired therapeutic effect. Hence, optimized exosomes can be developed via various engineering methods such as pharmacological compound preconditioned MSCs, genetically modified MSCs, or miRNA-loaded exosomes and peptide tagged exosomes to improve the targeting and therapeutic effects of exosomes. The biological characteristics, therapeutic potential, and optimizing strategy of exosomes will be described in our review.

Mesenchymal stem cell-derived exosomes containing miR-145-5p reduce inflammation in spinal cord injury by regulating the TLR4/NF-κB signaling pathway

ABSTRACT EXs (Exosomes) secreted by mesenchymal stem cells (MSCs) have the potential to treat spinal cord injury (SCI), this study aimed to further explore the therapeutic effect of EXs on SCI. Firstly, EXs were extracted from MSCs and analyzed with a transmission electron microscope. Next, MSCs with or without the miR-145-5p plasmid were injected into the SCI rat model, and then rat damage was evaluated by BBB score, HE staining and Nissl staining. And then Luciferase experiment verified the targeting relationship between miR-145-5p and TLR4. Furthermore, LPS-induced PC12 cells were established and incubated with Dil-labeled MSC-EXs to explore their effects on cell viability, apoptosis and inflammation through MTT, flow cytometry and ELISA, respectively. In addition, expressions of TLR4/NF-κB signaling pathway related factors were measured by qRT-PCR and Western blot. The results showed that after MSCs were successfully isolated, the existence of EXs in MSCs was confirmed. Moreover, MSC-EXs containing miR-145-5p improved functional recovery and reduced histopathological injury and inflammation in SCI rats. And MSC-EXs promoted miR-145-5p expression in spinal cord tissue and inhibited TLR4/NF-κB pathway activation in SCI rats. MSC-EXs inhibited LPS-induced inflammatory response and activation of the TLR4/NF-κB pathway in PC12 cells. In addition, we also found that miR-145-5p specifically targeted TLR4. TLR4 overexpression significantly reversed the effect of EX-miR-145-5p on maintaining PC12 cell viability, inhibiting apoptosis and inflammatory response, and activating TLR4/NF- κB pathway. In conclusion, mesenchymal stem cell-derived EXs containing miR-145-5p reduce inflammation in spinal cord injury by regulating the TLR4/NF-κB signaling pathway.

Engineered exosomes: desirable target-tracking characteristics for cerebrovascular and neurodegenerative disease therapies.

As extracellular vesicles secreted by cells, exosomes are intercellular signalosomes for cell communication and pharmacological effectors. Because of their special properties, including low toxicity and immunogenicity, biodegradability, ability to encapsulate endogenous biologically active molecules and cross the blood-brain barrier (BBB), exosomes have great therapeutic potential in cerebrovascular and neurodegenerative diseases. However, the poor targeting ability of natural exosomes greatly reduces the therapeutic effect. Using engineering technology, exosomes can obtain active targeting ability to accumulate in specific cell types and tissues by attaching targeting units to the membrane surface or loading them into cavities. In this review, we outline the improved targeting functions of bioengineered exosomes, tracing and imaging techniques, administration methods, internalization in the BBB, and therapeutic effects of exosomes in cerebrovascular and neurodegenerative diseases and further evaluate the clinical opportunities and challenges in this research field.

Human Adipose-Derived Mesenchymal Stem Cells-Derived Exosomal microRNA-19b Promotes the Healing of Skin Wounds Through Modulation of the CCL1/TGF-β Signaling Axis.

IntroductionHuman adipose-derived mesenchymal stem cells (ADMSCs) with their secretory factors are able to induce collagen synthesis and fibroblast migration in the wound healing process. This study is launched to figure out the effect of human ADMSCs-derived exosomes on skin wound healing.MethodsADMSCs were extracted and ADMSCs-derived exosomes were identified. Skin damage models were established by treating HaCaT cells and human skin fibroblasts with H2O2. Next, the roles of ADMSCs and their derived exosomes were investigated. The exosomal miRNA then was analyzed, and the function of miRNA on the H2O2-induced cells was studied by miRNA suppression. Bioinformatics analysis, luciferase activity and RIP assays were implemented to find the target genes ofthe miRNA and the modulated pathways. A mouse skin damage model was induced to elucidate the effects of exosomes in vivo by injecting exosomes.ResultsH2O2 treatment significantly reduced the viability of HaCaT cells and increased their apoptosis rate. Co-culture with ADMSCs or their derived exosomes could improve the cell damage caused by H2O2. Meanwhile, H2O2 treatment promoted the internalization of exosomes. ADMSCs and their derived exosomes significantly increased miR-19b expression in the recipient cells, while inhibiting miR-19b resulted in a reduction in the therapeutic effect of ADMSCs-derived exosomes. Besides, miR-19b regulated the TGF-β pathway by targeting CCL1. The therapeutic effect of exosomes was further confirmed by a mouse model of skin damage.ConclusionOur study indicates that exosomal miR-19b derived from ADMSCs regulates the TGF-β pathway by targeting CCL1, thereby promoting the healing of skin wounds.

Therapeutic effects of exosomes from angiotensin-converting enzyme 2 -overexpressed endothelial progenitor cells on intracerebral hemorrhagic stroke

ObjectiveWe have previously demonstrated that angiotensin-converting enzyme 2 (ACE2) could boost the therapeutic effects of endothelial progenitor cells (ACE2-EPCs) on stroke. However, where this effect comes from is still unclear. Here, we investigated whether the exosomes (EXs) released from ACE2-EPCs could provide the benefit for acute intracerebral hemorrhagic stroke (ICH). Methods: The C57BL/6 mice were induced ICH by collagenase injection, followed by intravenously administration of ACE2-EPC-EXs. ACE2 blocker, DX600 was used to verify the effects of ACE2. The neurological deficit score (NDS), hemorrhage volume, brain water content, and blood–brain barrier (BBB) permeability were measured at day 2 after injection. The levels of ACE2 and inflammatory factors/genes in the brain were also measured. Results: EPC-EXs decreased hemorrhage volume, brain edema, BBB permeability, and improved NDS, which were enhanced by ACE2-EPC-EXs treatment; 2) As compared to EPC-EXs, ACE2-EPC-EXs resulted in an up-regulation of ACE2 in the brain, associating with the down-regulated expressions of TNF-α and NFкB and up-regulated level of IκBα. 3) DX600 blocked the above mentioned protective effects of ACE2-EPC-EXs in ICH mice. Conclusion: These data suggest that the infusion of ACE2-EPC-EXs could provide the therapeutic effect on acute ICH by alleviating the post-stroke inflammation via transferring ACE2.

Exosomes derived from miR-155-5p-overexpressing synovial mesenchymal stem cells prevent osteoarthritis via enhancing proliferation and migration, attenuating apoptosis, and modulating extracellular matrix secretion in chondrocytes.

Synovial mesenchymal stem cells (SMSCs) have the potential to attenuate osteoarthritis (OA)-induced injury. The role and mechanism of SMSC-derived exosomes (SMSC-Exos), pivotal paracrine factors of stem cells, in OA-associated injury remain unclear. We aimed to confirm the effect of SMSC-Exos with specific modifications on OA-induced damage and to investigate the potential molecular mechanisms. Exosomes derived from miR-155-5p-overexpressing SMSCs (SMSC-155-5p-Exos) and SMSCs (SMSC-Exos) were isolated and characterized. CCK-8, Transwell, and Western blot analyses were used to detect proliferation, migration, extracellular matrix (ECM) secretion, and apoptosis of osteoarthritic chondrocytes. The therapeutic effect of exosomes in a mouse model of OA was examined using immunohistochemical staining and OARSI scores. SPSS 17.0 and GraphPad software were used for all statistical analyses in this study. The SMSC-Exos enhanced the proliferation and migration and inhibited the apoptosis of osteoarthritic chondrocytes but had no effect on ECM secretion. The miR-155-5p-overexpressing exosomes showed common characteristics of exosomes in vitro and further promoted ECM secretion by targeting Runx2. Thus, the SMSC-155-5p-Exos promoted proliferation and migration, suppressed apoptosis and enhanced ECM secretion of osteoarthritic chondrocytes, and effectively prevented OA in a mouse model. In addition, overexpression of Runx2 partially reversed the effect of the SMSC-155-5p-Exos on osteoarthritic chondrocytes. Given the insufficient effect of the SMSC-Exos on the ECM secretion of osteoarthritic chondrocytes, we modified the SMSM-Exos and demonstrated that the SMSC-155-5p-Exos could prevent OA. Exosomes derived from modified SMSCs may be a new treatment strategy to prevent OA. Graphical abstract.

Abstract WP135: Engineered Exosomes With Elevated Mir-27a Improve Neurological Outcome in Ischemic Mice

Background: Augmentation of axonal growth enhances improvement of neurological function after stroke. Our previous in vitro study demonstrated that miR-27a promotes axonal growth of embryonic neurons. The present in vivo study investigated whether exosomes carrying elevated miR-27a (27a-exos) enhance axonal growth and neurological outcome after stroke. Methods and Results: The 27a-exos were isolated from medium of mesenchymal stromal cells (MSCs) transfected with lenti-miR-27 vector. In order to investigate axonal growth and underlying mechanisms, Emx1-Thy1-YFP mice with selective expression of yellow fluorescent protein (YFP) in pyramidal neurons were subjected to the permanent middle cerebral artery occlusion (MCAO). Quantitative RT-PCR analysis showed that compared with exosomes derived from empty-vector transfected MSCs (empty-exos), 27a-exos had 3.7 fold increased miR-27a. 27a-exos (3x10 11 particles) were injected intravenously into mice at 24h after MCAO. Compared with control mice, the empty-exos (n=7) significantly (p<0.05) reduced the foot-fault (5±0.1 vs 11±0.5 in control) and the times to remove adhesive paper (seconds, 47±3 vs 70±4). However, compared with empty-exos, 27a-exos (n=7) further significantly (p<0.05) reduced foot-fault (3.0±0.2) and times to remove the paper (38±1.7). Histopathological and in situ hybridization analysis showed that 27a-exos localized to neurons and significantly (p<0.05) increased miR-27a in Emx1-YFP+ neurons (4±0.7 vs 1 in empty-exos), and augmented (p<0.05) the density of YFP+/pNFH+ axons (7±2 vs 1 in empty-exos). Moreover, 27a-exos substantially decreased the levels of the inhibitory protein Sema6a in the YFP+ axons in peri-infarct areas. Conclusion: Our data suggest that tailored 27a-exos augment the therapeutic effect of exosomes on stroke recovery and that suppression of axonal inhibitory proteins such as Sema6a may contribute to the 27a-exo-enhanced axonal outgrowth to promote neurological recovery post stroke.

Abstract 129: Brain-Heart Interaction After Stroke: Therapeutic Effects of Exosomes in Type 2 Diabetic Mice Subjected to Stroke

Aim: Diabetes exacerbates post-stroke cardiac injury. We tested whether treatment with exosomes harvested from human umbilical cord blood derived CD133+/KDR+ cells (CD133+Exo) improves neurological, cognitive and cardiac functional outcome in type 2 diabetes mellitus (T2DM) stroke mice. Methods: Adult (3-4m), male, db/db (T2DM) mice were subjected to distal middle cerebral artery occlusion (dMCAo) and treated with PBS or CD133+Exo (3х10 10 , i.v.) at 3 days after stroke (n=8/group). Serum exosomal microRNA (miR) expression was measured. Echocardiography, neurological and cognitive tests were performed, and mice were sacrificed at 28 days after stroke. Results: 1) Compared to T2DM-control, T2DM-stroke mice exhibit significantly decreased left ventricular ejection fraction (LVEF: db/db: 67.6±0.6%, db/db-dMCAo: 60.6±1.9%, p<0.05), significant cardiomyocyte hypertrophy, interstitial fibrosis, and decreased capillary density in heart indicating that stroke in T2DM mice induces cardiac dysfunction at 28 days after stroke. 2) Serum exosomal miR29b and miR126 expression was significantly decreased in T2DM-stroke mice compared to T2DM-control mice. CD133+Exo contain high levels of miR126 and miR29b. 3) CD133+Exo treatment in T2DM-stroke mice significantly promotes neurological functional recovery (foot-fault test), significantly improves cognitive outcome (Morris water maze (MWM) test and odor test), and significantly improves cardiac function (LVEF: db/db-dMCAo: 60.6±1.9%, db/db-dMCAo+CD133+Exo: 68.9±0.7%, p<0.05). 4) In T2DM-stroke mice with PBS or CD133+Exo treatment, cardiac function (LVEF) significantly correlates with cognitive outcome. 5) CD133+Exo treatment in T2DM-stroke mice significantly decreases myocardial fibrosis, decreases TGF-β and NOX2 expression, and increases heart tissue miR126 and miR29b expression, while decreasing expression of miR126 and miR29b target genes such as Spred-1 and DPP4. Conclusions: Stroke in T2DM mice induces significant cardiac dysfunction and CD133+Exo treatment improves neurological and cognitive outcome, and provides significant cardio-protection. The improvement in cardiac functional outcome highly correlates with cognitive functional recovery.

Exosomes derived from miR-146a-modified adipose-derived stem cells attenuate acute myocardial infarction-induced myocardial damage via downregulation of early growth response factor 1.

Multiple studies demonstrated that early growth response factor 1 (EGR1) induces myocardial damage after acute myocardial infarction (AMI). Recent evidence indicates that microRNAs (miRNA) play an important role in exosome-mediated cardioprotection after AMI. Bioinformatics analysis has shown that miR-146a can regulate the expression of EGR1, so the aim of this study was to determine if miR-146a plays a role in exosome-mediated cardioprotection by regulation of EGR1 after AMI. Exosomes were isolated from wild- or miR-146a-modified adipose-derived stem cells (ADSCs), and the therapeutic effect of exosomes was assessed in an AMI model in rats and hypoxic-induced H9c2 model cells. The results showed that miR-146a containing exosomes had more effect than the exosome treatment group on the suppression of AMI-induced apoptosis, inflammatory response, and fibrosis in an AMI rat model. Both in vivo and in vitro experiments found that miR-146a interacted with the 3'-untranslated region of EGR1 and suppressed posttranscriptional EGR1 expression, which was confirmed by the luciferase reporter assay. We also found that suppressed EGR1 expression reversed AMI or hypoxia-induced TLR4/NFκB signal activation, which played an important role in the promotion of myocardial cell apoptosis, inflammatory response, and fibrosis. Taken together, these findings suggested that exosomes derived from miR-146a-modified ADSCs attenuated AMI-induced myocardial damage via downregulation of EGR1.

Exosomes derived from MSCs ameliorate retinal laser injury partially by inhibition of MCP-1.

Although accumulated evidence supports the notion that mesenchymal stem cells (MSCs) act in a paracrine manner, the mechanisms are still not fully understood. Recently, MSC-derived exosomes (MSC-Exos), a type of microvesicle released from MSCs, were thought to carry functional proteins and RNAs to recipient cells and play therapeutic roles. In the present study, we intravitreally injected MSCs derived from either mouse adipose tissue or human umbilical cord, and their exosomes to observe and compare their functions in a mouse model of laser-induced retinal injury. We found that both MSCs and their exosomes reduced damage, inhibited apoptosis, and suppressed inflammatory responses to obtain better visual function to nearly the same extent in vivo. Obvious down-regulation of monocyte chemotactic protein (MCP)-1 in the retina was found after MSC-Exos injection. In vitro, MSC-Exos also down-regulated MCP-1 mRNA expression in primarily cultured retinal cells after thermal injury. It was further demonstrated that intravitreal injection of an MCP-1-neutralizing antibody promoted the recovery of retinal laser injury, whereas the therapeutic effect of exosomes was abolished when MSC-Exos and MCP-1 were administrated simultaneously. Collectively, these results suggest that MSC-Exos ameliorate laser-induced retinal injury partially through down-regulation of MCP-1.

Therapeutic effect of exosomes from indoleamine 2,3‐dioxygenase–positive dendritic cells in collagen‐induced arthritis and delayed‐type hypersensitivity disease models

We have demonstrated previously that dendritic cells (DCs) modified with immunosuppressive cytokines, and exosomes derived from DCs can suppress the onset of murine collagen-induced arthritis (CIA) and reduce the severity of established arthritis. Indoleamine 2,3-dioxygenase (IDO) is a tryptophan-degrading enzyme that is important for immune regulation and tolerance maintenance. DCs expressing functional IDO can inhibit T cells by depleting them of essential tryptophan and/or by producing toxic metabolites, as well as by generating Treg cells. This study was undertaken to examine the immunosuppressive effects of bone marrow (BM)-derived DCs genetically modified to express IDO, and of exosomes derived from IDO-positive DCs. BM-derived DCs were adenovirally transduced with IDO or CTLA-4Ig (an inducer of IDO), and the resulting DCs and exosomes were tested for their immunosuppressive ability in the CIA and delayed-type hypersensitivity (DTH) murine models. Both DCs and exosomes derived from DCs overexpressing IDO had an antiinflammatory effect in CIA and DTH murine models. The suppressive effects were partially dependent on B7 costimulatory molecules. In addition, gene transfer of CTLA-4Ig to DCs resulted in induction of IDO in the DCs and in exosomes able to reduce inflammation in an IDO-dependent manner. These results demonstrate that both IDO-expressing DCs and DC-derived exosomes are immunosuppressive and antiinflammatory, and are able to reverse established arthritis. Therefore, exosomes from IDO-positive DCs may represent a novel therapy for rheumatoid arthritis.