Fibroblast Exosomes Research Articles

Systemic Sclerosis Dermal Fibroblast Exosomes Trigger Type 1 Interferon Responses in Keratinocytes via a TBK/JAK/STAT Signaling Axis.

Activation of type I interferon (IFN) response has been shown to correlate with disease activity in systemic sclerosis (SSc). It is currently unknown whether the tissue-specific type I IFN activation is a consequence of the response observed in blood or rather its source. Exosomes from SSc fibroblasts were recently shown to activate macrophages in vitro. Here, we aimed to determine the source of type I IFN signature in SSc skin biopsies and the potential role of exosomes from SSc dermal fibroblasts in the process. Skin biopsies were obtained from the forearms of healthy patients and of those with SSc and processed for dermal fibroblasts and keratinocytes. Exosomes were isolated from healthy and SSc dermal fibroblast supernatants by ultracentrifugation and added to human skin keratinocytes. Keratinocyte transcriptome was analyzed by RNA sequencing (RNA-seq) analysis. TANK-binding kinase (TBK) and JAK were inhibited using a small molecule inhibitor (GSK8612) and tofacitinib, respectively. SSc skin biopsies showed the highest levels of type I IFN response in the epidermal layer. RNA-seq analysis of keratinocytes transcriptome following exposure to dermal fibroblast exosomes showed strong up-regulation of IFN signature genes induced by SSc exosomes compared to healthy control. Inhibition of TBK or JAK activity suppressed the up-regulation of the IFN signature induced by SSc exosomes. IFN activation of SSc keratinocytes is dependent on their crosstalk with dermal fibroblasts and inducible by extracellular exosomes. Our data indicate that SSc fibroblast exosomes contribute to the type I IFN activation in SSc skin through activation of pattern recognition receptors upstream of TBK.

Orchestration of Macrophage Polarization Dynamics by Fibroblast-Secreted Exosomes during Skin Wound Healing

Macrophages undertake pivotal yet dichotomous functions during skin wound healing, mediating both early pro-inflammatory immune activation and late anti-inflammatory tissue remodeling processes. The timely phenotypic transition of macrophages from inflammatory M1 to pro-resolving M2 activation states is essential for efficient healing. However, the endogenous mechanisms calibrating macrophage polarization in accordance with the evolving tissue milieu remain undefined. Here, we reveal an indispensable immunomodulatory role for fibroblast-secreted exosomes in directing macrophage activation dynamics. Fibroblast exosomes permitted spatiotemporal coordination of macrophage phenotypes independent of direct intercellular contact. Exosomes enhanced macrophage sensitivity to both M1 and M2 polarizing stimuli, yet also accelerated timely switching from M1 to M2 phenotypes. Exosomes inhibition dysregulated macrophage responses resulting in aberrant inflammation and impaired healing, while provision of exogenous fibroblast exosomes corrected defects. Topical application of fibroblast exosomes onto chronic diabetic wounds normalized dysregulated macrophage activation to resolve inflammation and restore productive healing. Our findings elucidate fibroblast-secreted exosomes as remote programmers of macrophage polarization that calibrate immunological transitions essential for tissue repair. Harnessing exosomes represents a previously unreported approach to steer productive macrophage activation states with immense therapeutic potential for promoting healing in chronic inflammatory disorders.

Cancer associated fibroblast secreted miR-432-5p targets CHAC1 to inhibit ferroptosis and promote acquired chemoresistance in prostate cancer.

Prostate cancer (PCa) ranks as the sixth most serious male malignant disease globally. While docetaxel (DTX) chemotherapy is the standard treatment for advanced PCa patients with distant metastasis, some individuals exhibit insensitivity or resistance to DTX. Cancer-associated fibroblasts (CAFs) play a pivotal role as stromal cells within the tumor microenvironment, influencing tumor development, progression, and drug resistance through exosomes. Ferroptosis, a novel form of programmed cell death, is characterized by intracellular iron accumulation that triggers lipid peroxidation, ultimately leading to cell demise. To delve into the potential mechanisms of chemotherapy resistance in prostate cancer, our research delved into the impact of CAF-derived exosomes on ferroptosis. Our findings revealed that CAF exosomes hindered the buildup of lipid reactive oxygen species (ROS) in prostate cancer cells induced by erastin, as well as mitigated erastin-induced mitochondrial damage, thereby impeding iron-induced cell death in prostate cancer cells. Furthermore, miR-432-5p was identified to diminish glutathione (GSH) consumption by targeting CHAC1, consequently inhibiting ferroptosis in prostate cancer cells. Our study found that miR-432-5p, originating from cancer-associated fibroblast (CAF) exosomes, suppresses ferroptosis by targeting CHAC1, thereby increasing resistance to docetaxel (DTX) in PCa. This research introduces a novel approach to address resistance to DTX.

Cancer-associated fibroblast exosomes promote prostate cancer metastasis through miR-500a-3p/FBXW7/HSF1 axis under hypoxic microenvironment.

Metastasis is the main cause of deaths in prostate cancer (PCa). However, the exact mechanisms underlying PCa metastasis are not fully understood. In this study, we discovered pronounced hypoxia in primary lesions of metastatic PCa(mPCa). The exosomes secreted by cancer-associated fibroblasts (CAFs) under hypoxic conditions significantly enhance PCa metastasis both in vitro and in vivo. Through miRNA sequencing and reverse transcription quantitative PCR (RT-qPCR), we found that hypoxia elevated miR-500a-3p levels in CAFs exosomes. Subsequent RT-qPCR, western blotting, and dual luciferase reporter assays identified F-box and WD repeat domain-containing 7(FBXW7) as a target of miR-500a-3p. In addition, immunohistochemistry revealed that FBXW7 expression decreased with the progression of PCa, while heat shock transcription factor 1(HSF1) expression increased. Introducing an FBXW7 plasmid into PCa cells reduced their metastatic potential and significantly lowered HSF1 expression. These findings suggest that CAFs exosomes drive PCa metastasis via the miR-500a-3p/FBXW7/HSF1 axis in a hypoxic microenvironment. Targeting either hypoxia or exosomal miR-500a-3p could be a promising strategy for PCa management.

O-107 - Modulation of immune cell polarization and PD-L1 expression by MF fibroblast exosomes: potential implications for immunotherapy in MF

O-107 - Modulation of immune cell polarization and PD-L1 expression by MF fibroblast exosomes: potential implications for immunotherapy in MF

Apoptosis of pro-B lymphocytes induced by NR4A1 activation in the presence of gingival fibroblast exosomes and TNFα, caspase 8, STAT3, and Akt pathways modulators.

There is a lack of data in the mainstream literature regarding the interactions between gingival fibroblasts, as a component of the local niche, and tumor precursors of B-lymphocytes. Although it is known that the development of tumors and tumor precursors depends on the local environment's characteristics. In order to experimentally evaluate the apoptosis of pro-B type lymphocytes, induced as a result of the known activation of orphan nuclear receptor 4A1 (NR4A1), through Cytosporone B (Csn-B, 10 μM), in the presence or absence of exosomes derived from gingival fibroblasts, we administered as a treatment: 1 μM R-7050 [functional inhibitor of tumor necrosis factor alpha (TNFα)], 1 μM Z-IETD-FMK (functional inhibitor of caspase 8), 1 μM GSK690693 (functional inhibitor of Akt 1∕2∕3 pathways) and, last but not least, 1 μM scutellarin [functional inhibitor of receptor activator of nuclear factor-kappa B ligand (RANKL)] and therefore of the signal transducer and activator of transcription 3 (STAT3) pathway. Firstly, it is really clear that the presence of exosomes in the pro-B lymphocytes culture medium amplified the apoptotic effects of 10 μM Csn-B. The inhibition of tumoral precursors development, namely the pro-B type, might be highly dependent on the inhibition of Akt 1∕2∕3 pathways, the first and most important consequence being apoptosis induced by the activation of NR4A1 orphan nuclear receptors.

Fibroblast-derived exosomal miRNA-133 promotes cardiomyocyte-like differentiation

ObjectiveTo investigate the role of exosomal miRNA-133 secreted by cardiac fibroblasts (CFs) in promoting cardiomyocyte differentiation. MethodsNeonatal rat CFs were cultured in vitro, and the cultured CFs were divided into three groups as follows: induction, miRNA-133 high expression, and miRNA-133 inhibition. miRNA-133 was transfected into CFs with lentivirus as a vector. CFs were transfected with the miRNA-133 inhibitor, and the markers of cardiomyocyte were detected through immunofluorescence staining, Western blotting, and real-time quantitative polymerase chain reaction (qRT-PCR) at 3, 8, and 14 days, respectively. The expression levels of cardiac troponin T (cTnT) and cardiac actin (α-actin) were determined, and qRT-PCR was used to detect the expression of miRNA-133 in the fibroblast exosomes. ResultsCFs subjected to immunofluorescence staining expressed vimentin and discoid domain receptor 2. The exosomes secreted by CFs were observed as small vesicles of 30–100 nm via transmission electron microscopy, and Western blotting was used to detect exosome-specific protein CD63 and CD9 expression. The expression levels of cTnT, α-actin, and exosomal miRNA-133 secreted into the supernatant of the miRNA-133 high-expression group increased gradually at different time points and reached the highest level at 14 days. The expression levels of cTnT, α-actin, and exosome miRNA-133 in the miRNA-133 inhibition group were the lowest. ConclusionThe exosomal miRNA-133, which is derived from CFs, can promote the differentiation of fibroblasts into cardiomyocyte-like cells.

Exosomes Derived from Epidermal Stem Cells Improve Diabetic Wound Healing

Diabetic foot ulceration is a major diabetic complication with unmet needs. We investigated the efficacy of epidermal stem cells and epidermal stem cells-derived exosomes (ESCs-Exo) in improving impaired diabetic wound healing and their mechanisms of action. Invitro experiments showed that ESCs-Exo enhanced the proliferation and migration of diabetic fibroblasts and macrophages and promoted alternative or M2 macrophage polarization. In wounds of db/db mice, treatment with both epidermal stem cells and ESCs-Exo, when compared with fibroblast exosomes and PBS control, accelerated wound healing by decreasing inflammation, augmenting wound cell proliferation, stimulating angiogenesis, and inducing M2 macrophage polarization. Multiplex protein quantification of wound lysates revealed TGFβ signaling influenced by ESCs-Exo. High-throughput sequencing of small RNAs contained in the ESCs-Exo showed higher proportions of microRNAs than those contained in fibroblast exosomes. In silico functional analysis showed that the ESCs-Exo microRNAs‒target genes were primarily involved in homeostatic processes and cell differentiation and highlighted regulatory control of phosphatidylinositol-3 kinase/protein kinase B and TGFβ signaling pathways. This was also validated invitro. Collectively, our results indicate that epidermal stem cells and ESCs-Exo are equally effective in promoting impaired diabetic wound healing and that ESCs-Exo treatment may be a promising and technically advantageous alternative to stem cell therapies.

Cancer-associated fibroblast exosomes promote chemoresistance to cisplatin in hepatocellular carcinoma through circZFR targeting signal transducers and activators of transcription (STAT3)/ nuclear factor -kappa B (NF-κB) pathway

ABSTRACT Chemoresistance in hepatocellular carcinoma (HCC) has been found to be influenced by exosomal transport of circRNAs. However, the role of circZFR in HCC chemoresistance still remains unclear. In the present study, circZFR was highly expressed in cisplatin (DDP)-resistant HCC cell lines and could regulate DDP resistance of the HCC cells. Also, circZFR was highly expressed in cancer-associated fibroblast (CAFs) and the exosome of CAFs. In addition, supplementation of CAFs in culture medium could promote DDP resistance of HCC cells. In vivo tumor xenograft experiments showed that knockdown of circZFR inhibited tumor growth and weakened DDP resistance, while CAFs-derived exosomes incubation increased the expression of circZFR, inhibited the STAT3/NF-κB pathway, promoted tumor growth, and enhanced DDP resistance. In general, CAFs-derived exosomes deliver circZFR to HCC cells, inhibit the STAT3/NF-κB pathway, and promote HCC development and chemoresistance. The results provided a new sight for the prevention and treatment of chemoresistance in HCC.

Exosome Marker Proteins of Tumor-Associated Fibroblasts and Exosome-Derived miR-92a-3p Act as Potential Biomarkers for Liver Cancer.

Many recent studies have shown that microRNAs (miRNAs) in exosomes can be absorbed by nearby or distant cells, and the abnormal expression of these exosomal miRNAs is associated with most pathological progresses. In this study, we explored the diagnostic value of exosome marker proteins and exosome-derived miR-92a-3p in liver cancer. The clinicopathological data of 60 patients with liver cancer admitted to Tanghan Gongren Hospital from October 2017 to October 2019 were collected. Tumor tissue and adjacent tissue were collected during surgery. Quantitative reverse transcription polymerase chain reaction and Western blot were used to detect the expression levels of miR-92a-3p in exosomes of fibroblasts and tumor tissue, and exosome marker proteins. In liver cancer tissue and fibroblast exosomes, the expression of miR-92a-3p was significantly increased. The receiver operator characteristic curve of the expression level of miR-92a-3p in exosomes and tissue showed that the area under the curve was 0.906 and 0.911, respectively. HSP70 and CD63 were highly expressed in the tissue of liver cancer and fibroblast exosomes. miR-92a-3p was positively correlated with HSP70 and CD63 in the exosomes of liver cancer fibroblasts. In addition, miR-92a-3p and exosome marker proteins (HSP70 and CD63) were highly expressed in tumors with a diameter greater than 5 cm, and were higher in liver cancer patients with BCLC stage B/C. Tumor fibroblast-derived exosome marker proteins and miR-92a-3p have good diagnostic value in liver cancer, indicating that they may be new diagnostic markers for liver cancer.

Achyranthes bidentata alcohol extract inhibits extracellular matrix degradation of the cartilage by regulating synovial fibroblast exosomes

Achyranthes bidentata alcohol extract inhibits extracellular matrix degradation of the cartilage by regulating synovial fibroblast exosomes

Multi-Quantum Dots-Embedded Silica-Encapsulated Nanoparticle-Based Lateral Flow Assay for Highly Sensitive Exosome Detection.

Exosomes are attracting attention as new biomarkers for monitoring the diagnosis and prognosis of certain diseases. Colorimetric-based lateral-flow assays have been previously used to detect exosomes, but these have the disadvantage of a high limit of detection. Here, we introduce a new technique to improve exosome detection. In our approach, highly bright multi-quantum dots embedded in silica-encapsulated nanoparticles (M–QD–SNs), which have uniform size and are brighter than single quantum dots, were applied to the lateral flow immunoassay method to sensitively detect exosomes. Anti-CD63 antibodies were introduced on the surface of the M–QD–SNs, and a lateral flow immunoassay with the M–QD–SNs was conducted to detect human foreskin fibroblast (HFF) exosomes. Exosome samples included a wide range of concentrations from 100 to 1000 exosomes/µL, and the detection limit of our newly designed system was 117.94 exosome/μL, which was 11 times lower than the previously reported limits. Additionally, exosomes were selectively detected relative to the negative controls, liposomes, and newborn calf serum, confirming that this method prevented non-specific binding. Thus, our study demonstrates that highly sensitive and quantitative exosome detection can be conducted quickly and accurately by using lateral immunochromatographic analysis with M–QD–SNs.

Mechanical stress promotes angiogenesis through fibroblast exosomes

BackgroundMechanical stress can induce multiple functional changes in vascular endothelial cells, including proliferation, differentiation, and migration. Furthermore, human fibroblasts are susceptible to external mechanical stress. In this work, we investigated whether mechanical stress can induce exosome secretion from fibroblasts to modulate angiogenesis. MethodsA CCK-8 cell proliferation assay was used to determine mechanical parameters. Then, exosomes from fibroblasts were isolated and characterized with regard to concentration and markers. We subsequently explored the effect of exosomes on proliferation, migration, and angiogenesis. Additionally, high-throughput sequencing was used to screen differentially expressed miRNAs in the mechanical stress-induced exosomes. ResultsA static stretching of 15% significantly enhanced the cell viability of the fibroblasts (p < 0.05) and significantly induced the secretion of exosomes from the fibroblasts, which had a stronger internalization ability. Further experiments demonstrated that the presence of static stretching-induced exosomes significantly increased cell proliferation, migration, and angiogenesis by regulating the Erk1/2 signaling pathway. Additionally, 12 up-regulated and 12 down-regulated candidate miRNAs were discriminated in the static stretching-induced exosomes. ConclusionOur findings conclusively demonstrate that static stretching-derived exosomes from fibroblasts promote angiogenesis through differentially expressed miRNAs, providing novel insights into the molecular mechanism by which mechanical stress influences angiogenesis.

Abstract 6414: Using 3D models to test the efficacy of targeting cancer-associated fibroblast exosomes to overcome chemoresistance in pancreatic cancer

Abstract Exosomes play a critical role in promoting proliferation and survival of cancer cells. These extracellular vesicles that range in size from 30-100nm in diameter are released by many different cell types and contain proteins, nucleic acids, and micro RNAs that can modify the content and state of recipient cells. Our previous studies have shown that cancer-associated fibroblasts (CAFs), which make up the bulk of pancreatic ductal adenocarcinoma (PDAC) tumors, hypersecrete exosomes upon chemotherapy treatment. When these exosomes were taken up by surrounding cancer cells, we observed more cell proliferation and drug resistance. Considering these findings, there is clearly a need of therapeutic strategies that target exosome biogenesis and secretion. Here, we investigate the effectiveness of several compounds, including farnesyl transferase inhibitors, imidazoles, and nonsteroidal anti-inflammatory drugs (NSAIDs), in blocking exosome secretion and suppressing chemoresistance in PDAC CAF and cancer cell lines. We observed decrease in exosome secretion upon ketoconazole, tipifarnib, and neticonazole treatment, using GW4869 (a neutral sphingomyelinase inhibitor) as our control. Furthermore, we established a 3D organoid model from our PDAC mouse models to better understand the impact of these drugs on exosome secretion in tumors with different genetic alterations. Together, our 2D and 3D models illuminate the potential for pharmacological targeting of exosome secretion as a treatment option that can improve the current standard-of-care treatment in PDAC. Citation Format: Chae Young Eun, Charlene DeKalb, Weikun Xiao, Xinyu Zhang, Reginald Hill. Using 3D models to test the efficacy of targeting cancer-associated fibroblast exosomes to overcome chemoresistance in pancreatic cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6414.

Comparison of Proangiogenic Effects of Adipose-Derived Stem Cells and Foreskin Fibroblast Exosomes on Artificial Dermis Prefabricated Flaps.

Large prefabricated flaps often suffer from necrosis or poor healing due to a lack of new blood vessels and related factors that promote angiogenesis. The innovative use of adipose-derived stem cell exosomes (ADSC-Exo) resolves the problem of vascularization of prefabricated flaps. We analyzed the differential microRNA (miRNA) expression in ADSC-Exo using next-generation sequencing (NGS) technology to explore their potential mechanisms in promoting vascularization. We observed that ADSC-Exo could significantly promote the vascularization of artificial dermis prefabricated flaps compared with human foreskin fibroblast exosomes. NGS indicated that there were some differentially expressed miRNAs in both exosomes. Bioinformatics analysis suggested that significantly upregulated hsa-miR-760 and significantly downregulated hsa-miR-423-3p in ADSC-Exo could regulate the expression of the ITGA5 and HDAC5 genes, respectively, to promote the vascularization of skin flaps. In summary, ADSC-Exo can promote skin-flap vascularization, and thereby resolve the problem of insufficient neovascularization of artificial dermis prefabricated flaps, thus expanding the application of prefabricated skin-flap transplantation.

Cardiac Fibroblasts and Cardiac Fibrosis: Precise Role of Exosomes.

Exosomes are a group of extracellular microvesicles that deliver biologically active RNAs, proteins, lipids and other signaling molecules to recipient cells. Classically, exosomes act as a vehicle by which cells or organs communicate with each other to maintain cellular/tissue homeostasis and to respond to pathological stress. Most multicellular systems, including the cardiovascular system, use exosomes for intercellular communication. In heart, endogenous exosomes from cardiac cells or stem cells aid in regulation of cell survival, cell proliferation and cell death; and thus tightly regulate cardiac biology and repair processes. Pathological stimulus in heart alters secretion and molecular composition of exosomes, thus influencing the above processes. The past decade has yielded increasing interest in the role of exosomes in the cardiovascular system and significant contribution of cardiac fibroblast (CF) and mediated cardiac fibrosis in heart failure, in this review we had overviewed the relevant literatures about fibroblast exosomes, its effect in the cardiovascular biology and its impact on cardiovascular disease (CVD). This review briefly describes the communication between fibroblasts and other cardiac cells via exosomes, the influence of such on myocardial fibrosis and remodeling, and the possibilities to use exosomes as biomarkers for acute and chronic heart diseases.

TGF-β induces a heart failure phenotype via fibroblasts exosome signaling

PurposeThe mechanisms for persistent and progressive loss of myocardial function in advanced heart failure (HF) remain incompletely characterized. In the current study, we sought to determine the impact of TGF-β on fibroblasts transcriptional profiles and assess if exosomes from TGF-β treated fibroblasts could induce a heart failure phenotype in co-cultured cardiomyocytes. MethodNormal heart fibroblasts were treated with TGF-β with a final conc. of 2.5 ng/ml in serum free media. HF fibroblasts were also obtained from patients undergoing implantation of left ventricular assist devices. Exosomes were collected using three-step ultracentrifugation. Cardiomyocytes were co-cultured with exosomes from TGF-β-treated, HF and control fibroblasts. RNA was extracted from the fibroblasts, exosomes, and the cardiomyocytes for a targeted panel of genes using Ion AmpliSeq. Fibroblast function was evaluated by collagen gel contraction. ResultsFibroblasts treated with TGF-β differentially express 21 of the 140 genes in our targeted panel. These fibroblasts exhibit enhanced collagen gel contraction similar to HF fibroblasts. Fifty of these targeted genes were also differentially expressed in fibroblast exosomes. Pathway analysis of these transcriptional changes suggest hypertrophic signaling to cardiac muscle. Cardiomyocytes, co-cultured with exosomes from TGF- β treated fibroblasts or heart failure patients, differentially expressed 40 genes compared to controls. Cardiomyocytes co-cultured with exosomes of TGF-β treated fibroblasts induced a molecular phenotype similar to cardiomyocytes co-cultured with exosomes from HF fibroblasts. These changes involve contractile proteins, adrenergic receptors, calcium signaling, metabolism and cell renewal. ConclusionTGF-β induces broad transcriptional changes in fibroblasts as well as their exosomes. These exosomes induce a heart failure phenotype in cardiomyocytes. Exosome signaling from fibroblasts likely contributes to disease progression in heart failure.

Intravenous administration of cardiac progenitor cell-derived exosomes protects against doxorubicin/trastuzumab-induced cardiac toxicity.

Combined administration of anthracyclines (e.g. doxorubicin; Dox) and trastuzumab (Trz), a humanized anti-human epidermal growth factor receptor 2 (HER2; ErbB2), is an effective treatment for HER2-positive breast cancer. However, both agents are associated with cardiac toxicity. Human cardiac-resident mesenchymal progenitor cells (CPCs) secrete extracellular vesicles including nanosized exosomes which protect against myocardial ischaemia. Here, we investigated the effects of these exosomes using a novel model of Dox/Trz-mediated cardiotoxicity. CPCs were derived from cardiac atrial appendage specimens from patients who underwent heart surgery for heart valve disease and/or ischaemic heart disease, and exosomes were purified from CPC conditioned media. Proteomics analyses revealed that CPC exosomes contained multiple proteins involved in redox processes. Dox/Trz induced a significant increase in reactive oxygen species (ROS) in rat cardiomyocytes, which was prevented by CPC exosomes. In vivo, rats received six doses of Dox (Days 1-11), followed by six doses of Trz (Days 19-28). Three doses of either exosomes or exosome suspension vehicle were injected intravenously on Days 5, 11, and 19 in the treatment and control groups, respectively. Dox/Trz induced myocardial fibrosis, CD68+ inflammatory cell infiltrates, inducible nitric oxide synthase expression, and left ventricular dysfunction. CPC exosomes prevented these effects. These vesicles were highly enriched in miR-146a-5p compared with human dermal fibroblast exosomes. Dox upregulated Traf6 and Mpo, two known miR-146a-5p target genes (which encode signalling mediators of inflammatory and cell death axes) in myocytes. CPC exosomes suppressed miR-146a-5p target genes Traf6, Smad4, Irak1, Nox4, and Mpo in Dox-treated cells. Specific silencing of miR-146a-5p abrogated exosome-mediated suppression of those genes leading to an increase in Dox-induced cell death. Human CPC exosomes attenuate Dox-/Trz-induced oxidative stress in cardiomyocytes. Systemic administration of these vesicles prevents Dox/Trz cardiotoxicity in vivo. miR-146a-5p mediates some of the benefits of exosomes in this setting.

Exosomes from endothelial progenitor cells improve outcomes of the lipopolysaccharide-induced acute lung injury

BackgroundThe acute respiratory distress syndrome (ARDS) is characterized by disruption of the alveolar-capillary barrier resulting in accumulation of proteinaceous edema and increased inflammatory cells in the alveolar space. We previously found that endothelial progenitor cell (EPC) exosomes prevent endothelial dysfunction and lung injury in sepsis in part due to their encapsulation of miRNA-126. However, the effects of EPC exosomes in acute lung injury (ALI) remain unknown.MethodsTo determine if EPC exosomes would have beneficial effects in ALI, intratracheal administration of lipopolysaccharide (LPS) was used to induce ALI in mice. Lung permeability, inflammation, and the role of miRNA-126 in the alveolar-epithelial barrier function were examined.ResultsThe intratracheal administration of EPC exosomes reduced lung injury following LPS-induced ALI at 24 and 48 h. Compared to placebo, intratracheal administration of EPC exosomes significantly reduced the cell number, protein concentration, and cytokines/chemokines in the bronchoalveolar lavage fluid (BALF), indicating a reduction in permeability and inflammation. Further, EPC exosomes reduced myeloperoxidase (MPO) activity, lung injury score, and pulmonary edema, demonstrating protection against lung injury. Murine fibroblast (NIH3T3) exosomes, which do not contain abundant miRNA-126, did not provide these beneficial effects. In human small airway epithelial cells (SAECs), we found that overexpression of miRNA-126-3p can target phosphoinositide-3-kinase regulatory subunit 2 (PIK3R2), while overexpression of miRNA-126-5p inhibits the inflammatory alarmin HMGB1 and permeability factor VEGFα. Interestingly, both miR-126-3p and 5p increase the expression of tight junction proteins suggesting a potential mechanism by which miRNA-126 may mitigate LPS-induced lung injury.ConclusionsOur data demonstrated that human EPC exosomes are beneficial in LPS-induced ALI mice, in part through the delivery of miRNA-126 into the injured alveolus.

Abstract 5397: ExomiRs can distinguish tumor-associated from normal stroma: Potential biomarkers in colorectal cancer

Abstract There is urgent need for prognostic markers to stratify intermediate-stage colorectal cancer (CRC) patients for the benefit of adjuvant therapy. Tumor heterogeneity is a major obstacle in stratification attempts as rare cancer cell populations may display stem cell properties and allow generation of therapy resistance. Tumor stroma, on the other hand, is less susceptible to genetic alterations than cancer cells, providing signals that are more reproducible across patient samples. Exosome encapsulated microRNAs (exomiRs) are particularly amenable to biomarker development because they circulate, closely resemble the tissue of origin and are inherently stable. We sought to identify a stromal exomiR signature in colorectal cancer with biomarker potential. Paired primary tumor-associated and normal fibroblasts were extracted from human colonic tissue. Exosomes were isolated by differential ultracentrifugation, validated according to International Society for Extracellular Vesicles recommendations, and profiled for over 800 microRNAs (miRNAs) by NanoString. Data preprocessing and normalization was conducted prior to differential expression analysis. Candidate miRNAs were validated by qPCR. Pathway and network analyses were conducted using miRPath and Ingenuity Pathway Analysis. Forty one exomiRs were differentially present in tumor-associated and normal fibroblasts. Of these, 21 were more abundant in tumor-associated fibroblasts. Thirty-six KEGG pathways were found to be regulated by this exomiR signature, such as “PI3K-Akt” and “colorectal cancer.” A potential target of these exomiRs is PHLPP2, which encodes a phosphatase acting on AKT. In keeping with this, exposure to fibroblast exosomes increased AKT phosphorylation and that of its direct target Bad, in CRC cells, potentially due to a decrease in PHLPP2 protein abundance. Consequently, these cells were protected from drug-induced apoptosis. For the first time, stromal exomiRs have been profiled in colorectal cancer. Tumor-associated and normal stroma can be distinguished by a specific exomiR signature, which is potentially functionally important. Further mechanistic characterization is now required to identify the clinical significance of stromal exomiRs. Citation Format: Rahul Bhome, Rebecca Goh, Nir Pillar, Noam Shomron, Emre Sayan, Alex Mirnezami. ExomiRs can distinguish tumor-associated from normal stroma: Potential biomarkers in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5397.