Potential Of Exosomes Research Articles

Potential of Exosomes as Multifunctional Nanocarriers for Targeted Drug Delivery.

Exosomes are small vesicles that form when multivesicular bodies fuse with the plasma membrane and are released into body fluids. They play a vital role in facilitating communication between cells by transferring different biomolecules, including DNA, RNA, proteins, and lipids, over both short and long distances. They also function as vital mediators in both states of health and disease, exerting an impact on several physiological processes. Exosomes have been modified to overcome the limitations of natural exosomes to enhance their potential as carriers for drug delivery systems, and these modifications aim to improve the drug delivery efficiency, enhance tissue and organ targeting, and prolong the circulating half-life of exosomes. This review discussed recent advancements in exosome nanotechnology, as well as the progression and use of exosomes for drug delivery. The potential commercialisation and challenges associated with the use of exosome-based drug delivery systems were also discussed, aiming to motivate the development of exosome-based theranostic nanoplatforms and nanotechnology for improved healthcare treatments.

The potential of exosomes from adipose-derived stromal-vascular fraction in Increasing Migration Activity of Human Dental Pulp Stromal Cells (in vitro study)

BackgroundMigration of dental pulp stromal cells (DPSCs) significantly responds to wound healing after pulp injury. Deriving from low compliance characteristics, pulp tissue regeneration is challenging and depends on the microenvironmental signals. Exosomes can maintain and carry bioactive proteins that are crucial in cell communication. Adipose tissue-derived stromal vascular fraction (AD-SVF), a heterogeneous group of progenitor cells, is a promising source of exosomes. ObjectiveDiscover the impact of exosomes derived from an adipose-derived stromal-vascular fraction (AD-SVF Exo) on human dental pulp stromal cells (hDPSCs) migration. Methods: In-vitro design involving AD-SVF Exo applied to hDPSCs cultivated until 80% confluence and 3rd-4th passage. AD-SVF Exo isolation through size exclusion chromatography (SEC). The AD-SVF Exo was characterized using Nanoparticle Tracking Analysis (NTA) and flow cytometry assays. hDPSCs were exposed to AD-SVF Exo (0% as the control group, 0.1%, and 1% as the experimental group), subjected to a scratch wound assay, and observed at 6, 24, and 48 h. ResultshDPSCs cultured expressed mesenchymal stem cell mesenchymal stem cell (MSC) markers and formed loose colonies with characteristic spindle-shaped morphology. AD-SVF Exo consisted of marker proteins CD9 and CD63, and NTA measurement demonstrated a diameter of 103 ± 24 nm in diameter with 1,6 x 108 particles/ml. Based on scratch assay, hDPSCs migration activity improved by reduced wound area in experimental groups. Data analyzed utilizing the Friedman (p < 0.001), and Kruskal Wallis (p < 0.05) test indicated differences in wound area after exposure of 0.1 % and 1 % AD-SVF Exo and observed at 6, 24, and 48 h. ConclusionAccording to the findings of this research, AD-SVF Exo successfully enhances the wound healing capabilities of hDPSCs by improved migration activity, with the highest result found in 0.1% AD-SVF Exo.

Exosomal noncoding RNAs: decoding their role in thyroid cancer progression.

Exosomes, as pivotal entities within the tumor microenvironment, orchestrate intercellular communication through the transfer of diverse molecules, among which non-coding RNAs (ncRNAs) such as miRNAs, lncRNAs, and circRNAs play a crucial role. These ncRNAs, endowed with regulatory functions, are selectively incorporated into exosomes. Emerging evidence underscores the significance of exosomal ncRNAs in modulating key oncogenic processes in thyroid cancer (TC), including proliferation, metastasis, epithelial-mesenchymal transition (EMT), angiogenesis, and immunoediting. The unique composition of exosomes shields their cargo from enzymatic and chemical degradation, ensuring their integrity and facilitating their specific expression in plasma. This positions exosomal ncRNAs as promising candidates for novel diagnostic and prognostic biomarkers in TC. Moreover, the potential of exosomes in the therapeutic landscape of TC is increasingly recognized. This review aims to elucidate the intricate relationship between exosomal ncRNAs and TC, fostering a deeper comprehension of their mechanistic involvement. By doing so, it endeavors to propel forward the exploration of exosomal ncRNAs in TC, ultimately paving the way for innovative diagnostic and therapeutic strategies predicated on exosomes and their ncRNA content.

Potential of Exosomes as Therapeutics and Therapy Targets in Cancer Patients

After an initial positive response to chemotherapy, cancer patients often acquire chemoresistance and tumor relapse which make cancer to the most lethal diseases worldwide. Exosomes are essential mediators of cell-to-cell communication by delivering their cargo, such as proteins, RNAs and DNA from cell to cell. They participate in cancer progression, metastasis, immune response and therapy resistance. Their ability to shuttle between cells make them to efficient drug delivery systems. As drug transporters, they provide novel strategies for cancer therapy by advancing targeted drug therapy and improving the therapeutic effects of anti-cancer medications. With this review, a comprehensive overview on the potential of exosomes as therapeutics agents and targeted molecules in the treatment of cancer patients is given. The current challenges of preparation of loading exosomes with drugs and delivering them to the recipient tumor cells as well as a consequent exosome-mediated cancer therapy are also discussed.

The Regulation of Exosome Generation and Function in Physiological and Pathological Processes.

Exosomes, a type of extracellular vesicle with a diameter of approximately 100 nm that is secreted by all cells, regulate the phenotype and function of recipient cells by carrying molecules such as proteins, nucleic acids, and lipids and are important mediators of intercellular communication. Exosomes are involved in various physiological and pathological processes such as immunomodulation, angiogenesis, tumorigenesis, metastasis, and chemoresistance. Due to their excellent properties, exosomes have shown their potential application in the clinical diagnosis and treatment of disease. The functions of exosomes depend on their biogenesis, uptake, and composition. Thus, a deeper understanding of these processes and regulatory mechanisms can help to find new targets for disease diagnosis and therapy. Therefore, this review summarizes and integrates the recent advances in the regulatory mechanisms of the entire biological process of exosomes, starting from the formation of early-sorting endosomes (ESCs) by plasma membrane invagination to the release of exosomes by fusion of multivesicular bodies (MVBs) with the plasma membrane, as well as the regulatory process of the interactions between exosomes and recipient cells. We also describe and discuss the regulatory mechanisms of exosome production in tumor cells and the potential of exosomes used in cancer diagnosis and therapy.

Targeted expression of a designed fusion protein containing BMP2 into the lumen of exosomes

BackgroundExosomes are 30–150 nm membrane vesicles, originating from the endocytic pathway. By acting as natural carriers of biomolecules, they can transfer various materials to recipient cells. Therefore, discovering novel strategies for cargo packaging into exosomes is crucial. MethodsThe fusion constructs, consisting of protein of interest (BMP2) along with the targeting motif, linkers, tracking proteins, and enzyme cleavage sites, were computationally designed. Following the homology modeling, the best structure was selected and subjected to molecular dynamics (MD) simulation and docking analyses. The fusion protein gene was expressed in the HEK-293LTV cell line. The high-efficiency transfected and transduced cells were screened and their exosomes were isolated. Finally, cell and exosome lysates were evaluated for expression of the fusion protein. ResultsA total of 12 constructs with lengths ranging from 483 to 496 were designed. The top three templates, 1REW, 2H5Q, and 2MOF were screened. MD simulation and docking analyses of the structures revealed their stability and functionality. In the protein expression analyses, three bands at sizes of approximately 60, 25, and 12.5 kDa were observed, consistent with the sizes of the complete fusion protein, dimeric, and monomeric BMP2 protein. The presence of a 12.5 kDa band at exosome lysate analysis might suggest that it was loaded and cleaved inside exosomes. ConclusionIn summary, these findings revealed that the proposed idea for cargo sorting within the exosome lumen through incorporating an appropriate cleavage site was effective, thus providing further insight into the potential of exosomes as nano-shuttles bearing therapeutic biomolecules.

Role of Stem Cell-Derived Exosomes and microRNAs in Spinal Cord Injury.

Neurological disorders represent a global health problem. Current pharmacological treatments often lead to short-term symptomatic relief but have dose-dependent side effects, such as inducing orthostatic arterial hypotension due to the blockade of alpha receptors, cardiotoxic effects due to impaired repolarization, and atrioventricular block and tachycardia, including ventricular fibrillation. These challenges have driven the medical community to seek effective treatments for this serious global health threat. Mesenchymal stem cells (MSCs) are pluripotent cells with anti-inflammatory, anti-apoptotic, and immunomodulatory properties, providing a promising alternative due to their ability to differentiate, favorable culture conditions, in vitro manipulation ability, and robust properties. Although MSCs themselves rarely differentiate into neurons at the site of injury after transplantation in vivo, paracrine factors secreted by MSCs can create environmental conditions for cell-to-cell communication and have shown therapeutic effects. Recent studies have shown that the pleiotropic effects of MSCs, particularly their immunomodulatory potential, can be attributed primarily to these paracrine factors. Exosomes derived from MSCs are known to play an important role in these effects. Many studies have evaluated the potential of exosome-based therapies for the treatment of various neurological diseases. In addition to exosomes, various miRNAs derived from MSCs have been identified to regulate genes and alleviate neuropathological changes in neurodegenerative diseases. This review explores the burgeoning field of exosome-based therapies, focusing on the effects of MSC-derived exosomes and exosomal miRNAs, and summarizes recent findings that shed light on the potential of exosomes in the treatment of neurological disorders. The insights gained from this review may pave the way for innovative and effective treatments for these complex conditions. Furthermore, we suggest the therapeutic effects of exosomes and exosomal miRNAs from MSCs, which have a rescue potential in spinal cord injury via diverse signaling pathways.

Development of stem cell therapy for atherosclerosis.

Cardiovascular disease (CVD) has a high incidence and low cure rate worldwide, and atherosclerosis (AS) is the main factor inducing cardiovascular disease, of which lipid deposition in the vessel wall is the main marker of AS. Currently, although statins can be used to lower lipids and low-density lipoprotein (LDL) in AS, the cure rate for AS remains low. Therefore, there is an urgent need to develop new therapeutic approaches, and stem cells are now widely studied, while stem cells are a class of cell types that always maintain the ability to differentiate and can differentiate to form other cells and tissues, and stem cell transplantation techniques have shown efficacy in the treatment of other diseases. With the establishment of cellular therapies and continued research in stem cell technology, stem cells are also being used to address the problem of AS. In this paper, we focus on recent research advances in stem cell therapy for AS and briefly summarize the relevant factors that induce the formation of AS. We mainly discuss the efficacy and application prospects of mesenchymal stem cells (MSCs) for the treatment of AS, in addition to the partial role and potential of exosomes in the treatment of AS. Further, provide new ideas for the clinical application of stem cells.

Neuronal exosomes as a new signaling system

Every year more and more works are devoted to the study of neuronal exosomes. The potential of exosomes as diagnostic markers for neurodegenerative diseases has been significantly explored., and similar marker search patterns have been adopted for the study of psychiatric pathologies. The fundamentals of exosome biogenesis in different cell types have been elucidated., the physiological significance of exosomes is being actively studied., and many aspects of signaling with their participation are being elucidated. At the same time., data have been accumulated pointing to the role of exosomal signaling as an important element of interneuronal communication. Do we have enough evidence to call exosomes a new non-canonical neurotransmitter in the brain? This discussion work is devoted to answering this question., in which the author presents to the scientific community the concept of the possible role of brain exosomes as a signaling system.

Shedding Lights on the Extracellular Vesicles as Functional Mediator and Therapeutic Decoy for COVID-19

COVID-19 is an infectious disease caused by the novel coronavirus (SARS-CoV-2) that first appeared in late 2019 and has since spread across the world. It is characterized by symptoms such as fever, cough, and shortness of breath and can lead to death in severe cases. To help contain the virus, measures such as social distancing, handwashing, and other public health measures have been implemented. Vaccine and drug candidates, such as those developed by Pfizer/BioNTech, AstraZeneca, Moderna, Novavax, and Johnson & Johnson, have been developed and are being distributed worldwide. Clinical trials for drug treatments such as remdesivir, dexamethasone, and monoclonal antibodies are underway and have shown promising results. Recently, exosomes have gained attention as a possible mediator of the COVID-19 infection. Exosomes, small vesicles with a size of around 30-200 nm, released from cells, contain viral particles and other molecules that can activate the immune system and/or facilitate viral entry into target cells. Apparently, the role of exosomes in eliciting various immune responses and causing tissue injury in COVID-19 pathogenesis has been discussed. In addition, the potential of exosomes as theranostic and therapeutic agents for the treatment of COVID-19 has been elaborated.

Current Status, Opportunities, and Challenges of Exosomes in Oral Cancer Diagnosis and Treatment.

Oral cancer is one of the most common cancers in the world, with more than 300,000 cases diagnosed each year, of which oral squamous cell carcinoma accounts for more than 90%, with a 5-year survival rate of only 40–60%, and poor prognosis. Exploring new strategies for the early diagnosis and treatment of oral cancer is key to improving the survival rate. Exosomes are nanoscale lipid bilayer membrane vesicles that are secreted by almost all cell types. During the development of oral cancer, exosomes can transport their contents (DNA, RNA, proteins, etc) to target cells and promote or inhibit the proliferation, invasion, and metastasis of oral cancer cells by influencing the host immune response, drug-resistant metastasis, and tumour angiogenesis. Therefore, exosomes have great potential and advantages as biomarkers for oral cancer diagnosis, and as drug delivery vehicles or targets for oral cancer therapy. In this review, we first describe the biogenesis, biological functions, and isolation methods of exosomes, followed by their relationship with oral cancer. Here, we focused on the potential of exosomes as oral cancer biomarkers, drug carriers, and therapeutic targets. Finally, we provide an insightful discussion of the opportunities and challenges of exosome application in oral cancer diagnosis and treatment, intending to offer new ideas for the clinical management of oral cancer.

The therapeutic potential of exosomes derived from mesenchymal stem cells in experimentally induced hypertensive encephalopathy

The therapeutic potential of exosomes derived from mesenchymal stem cells in experimentally induced hypertensive encephalopathy

Isolation of Platelet-Derived Exosomes from Human Platelet-Rich Plasma: Biochemical and Morphological Characterization.

Platelet-Rich Plasma (PRP) is enriched in molecular messengers with restorative effects on altered tissue environments. Upon activation, platelets release a plethora of growth factors and cytokines, either in free form or encapsulated in exosomes, which have been proven to promote tissue repair and regeneration. Translational research on the potential of exosomes as a safe nanosystem for therapeutic cargo delivery requires standardizing exosome isolation methods along with their molecular and morphological characterization. With this aim, we isolated and characterized the exosomes released by human PRP platelets. Western blot analysis revealed that CaCl2-activated platelets (PLT-Exos-Ca2+) released more exosomes than non-activated ones (PLT-Exos). Moreover, PLT-Exos-Ca2+ exhibited a molecular signature that meets the most up-to-date biochemical criteria for platelet-derived exosomes and possessed morphological features typical of exosomes as assessed by transmission electron microscopy. Array analysis of 105 analytes including growth factors and cytokines showed that PLT-Exos-Ca2+ exhibited lower levels of most analytes compared to PLT-Exos, but relatively higher levels of those consistently validated as components of the protein cargo of platelet exosomes. In summary, the present study provides new insights into the molecular composition of human platelet-derived exosomes and validates a method for isolating highly pure platelet exosomes as a basis for future preclinical studies in regenerative medicine and drug delivery.

Integrated view of molecular diagnosis and prognosis of dengue viral infection: future prospect of exosomes biomarkers.

Dengue viruses (DENVs) are the viruses responsible for dengue infection which affects lungs, liver, heart and also other organs of individuals. DENVs consist of the group of four serotypically diverse dengue viruses transmitted in tropical and sub-tropical countries of world. Aedes mosquito is the principal vector which spread the infection from infected person to healthy humans. DENVs can cause different syndromes depending on serotype of virus which range from undifferentiated mild fever to dengue hemorrhagic fever resulting in vascular leakage due to release of cytokine and Dengue shock syndrome with fluid loss and hypotensive shock, or other severe manifestations such as bleeding and organ failure. Increase in dengue cases in pediatric population is a major concern. Transmission of dengue depends on various factors like temperature, rainfall, and distribution of Aedes aegypti mosquitoes. The present review describes a comprehensive overview of dengue, pathophysiology, diagnosis, treatment with an emphasis on potential of exosomes as biomarkers for early prediction of dengue in pediatrics.

The Potential of Exosomes in Allergy Immunotherapy.

Allergic diseases represent a global health and economic burden of increasing significance. The lack of disease-modifying therapies besides specific allergen immunotherapy (AIT) which is not available for all types of allergies, necessitates the study of novel therapeutic approaches. Exosomes are small endosome-derived vesicles delivering cargo between cells and thus allowing inter-cellular communication. Since immune cells make use of exosomes to boost, deviate, or suppress immune responses, exosomes are intriguing candidates for immunotherapy. Here, we review the role of exosomes in allergic sensitization and inflammation, and we discuss the mechanisms by which exosomes could potentially be used in immunotherapeutic approaches for the treatment of allergic diseases. We propose the following approaches: (a) Mast cell-derived exosomes expressing IgE receptor FcεRI could absorb IgE and down-regulate systemic IgE levels. (b) Tolerogenic exosomes could suppress allergic immune responses via induction of regulatory T cells. (c) Exosomes could promote TH1-like responses towards an allergen. (d) Exosomes could modulate IgE-facilitated antigen presentation.

Diagnostic Potential of Exosomal HypoxamiRs in the Context of Hypoxia-Sumoylation-HypoxamiRs in Early Onset Preeclampsia at the Preclinical Stage.

As the search for non-invasive preclinical markers of preeclampsia (PE) expands, the number of studies on the diagnostic potential of exosomes is growing. Changes in the partial pressure of oxygen caused by impaired uteroplacental perfusion in PE are a powerful inducer of increased production and release of exosomes from cells, which also determine their cargo. At the same time, the expression pattern of oxygen-dependent microRNAs (miRNAs), called “hypoxamiRs”, is modulated, and their packing into exosomes is strictly regulated by sumoylation. In connection therewith, we emphasize the evaluation of exosomal hypoxamiR expression (miR-27b-3p, miR-92b-3p, miR-181a-5p, and miR-186-5p) using quantitative RT-PCR, as well as SUMO 1–4 and UBC9 (by Western blotting), in pregnant women with early-onset PE. The findings show that miR-27b-3p and miR-92b-3p expression was significantly changed at 11–14 and 24–26 weeks of gestation in the blood plasma of pregnant women with early-onset PE, which subsequently manifested. High sensitivity and specificity (AUC = 1) were demonstrated for these miRNAs in the first trimester, and significant correlations with a decrease in hemoglobin (r = 0.71, p = 0.002; r = −0.71, p = 0.002) were established. In mid-pregnancy, the miR-27b-3p expression was found to correlate with an increase in platelets (r = −0.95, p = 0.003), and miR-92b-3p was associated with a decrease in the prothrombin index (r = 0.95, p = 0.003). Specific exomotifs of studied miRNAs were also identified, to which the sumoylated ribonucleoprotein hnRNPA2/B1 binds, carrying out their packaging into exosomes. The expression of conjugated SUMO 1 (p = 0.05), SUMO 2/3/4 (p = 0.03), and UBC9 (p = 0.1) was increased in exosomes at early-onset PE, and the expression of free SUMO 1 (p = 0.03) and SUMO 2/3/4 (p = 0.01) was significantly increased in the placenta, as an adaptive response to hypoxia. Moreover, SUMO 2/3/4 was negatively correlated with miR-27b-3p expression in the placenta. In conclusion, the diagnostic potential of exosomal hypoxamiRs mediated by sumoylation may form the basis for the development of combined specific targets for the treatment of early-onset PE, as hnRNPA2/B1 is a target of miR-27b-3p, and its sumoylation creates miR-27b-3p–hnRNPA2/B1–SUMO 1–4 cross-talk.

Differences in the Quantity and Composition of Extracellular Vesicles in the Aqueous Humor of Patients with Retinal Neovascular Diseases.

Extracellular vesicles (EVs) are secreted by various cells in the body fluid system and have been found to influence vessel formation and inflammatory responses in a variety of diseases. However, which EVs and their subtypes are involved in vascular retinal diseases is still unclear. Therefore, the aim of this study was to explore the particle distribution of EVs in retinal neovascular diseases, including age-related macular degeneration, polypoidal choroidal vasculopathy, and central retinal vein occlusion. The aqueous humor was harvested from 20 patients with different retinal neovascular diseases and six patients with cataracts as the control group. The particle distribution was analyzed using nanoparticle tracking analysis (NTA) and transmitting electron microscopy (TEM). The results revealed that the disease groups had large amounts of EVs and their subtypes compared to the control group. After isolating exosomes, a higher expression of CD81+ exosomes was shown in the disease groups using flow cytometry. The exosomes were then further classified into three subtypes of exomeres, small exosomes, and large exosomes, and their amounts were shown to differ depending on the disease type. To the best of our knowledge, this is the first study to elucidate the dynamics of EVs in retinal neovascular diseases using clinical cases. Our findings demonstrated the possible functionality of microvesicles and exosomes, indicating the potential of exosomes in the diagnosis and therapy of retinal neovascular diseases.

EXOSOME NANOCARRIERS: BASIC BIOLOGY, DIAGNOSIS, NOVEL AND PERSPECTIVE APPROACH IN DRUG DELIVERY SYSTEMS: A REVIEW

Exosomes are the extracellular vesicles surrounded by a phospholipid bilayer shed from all cell varieties and plays a significant role in the communication and Transportation of materials between the cells due to their ability to transfer the proteins and nucleic acids from One cell to the another cell. Analogous in size and performance to synthetic nanoparticles, exosomes provide several Advantages, rendering them the foremost promising candidates for targeted drug or gene delivery vehicles. This review highlights the isolation techniques and delivery potential of exosomes, and equally presents research or analysis gaps for enhancing the use of natural vesicles for delivery functions. Exosome-based drug formulations can be applied to an extensive variety of diseases such as various infectious, cardiovascular, cancer and neurodegenerative disorders. Mostly, exosomes combine the benefits of both synthetic nanocarriers and cell-mediated drug delivery systems however avoiding their limitations.

The role of exosomes in the mechanisms of inflammation development in patients with cardiovascular pathology and the contribution to therapeutic potential of stem cells

The aim – based on the analysis of the scientific literature focused on understanding the role of exosomes in the mechanisms of inflammation development and application of stem cells for cellular therapy in different pathological conditions, to identify and substantiate the prospects of using the exosomes as prognostic markers of a disease progression and application of their therapeutic potential in cardiovascular pathology. Global trends in the study of stem cells of different origins from the perspective of morphofunctional, molecular-genetic, cytogenetic, immunogenetic and cytological characteristics contribute significantly the development of regenerative medicine in the context of developing new methodological solutions for the use of stem cells and their components, particularly exosomes, for cell therapy of various pathological conditions. Studies show the indirect effect of exosomes on the immune response activation, coordination of cellular senescence processes and antigen presentation. There are also evidence of their impact on the structural and functional restoration of affected organs and blood vessels. The application potential of exosomes in practical medicine, particularly in the area of new approaches development to synthesize the newer biopharmaceuticals and as markers of multifactorial pathology course in conjunction with studies on the mechanisms of exosome involvement into immune processes is discussed. The study on the exosome-mediated mechanisms of inflammation in atherosclerosis is relevant, given the fact that their main physiological role is to implement the link between immunocompetent cells. Conclusions. Improving knowledge of the molecular biological mechanisms of the exosome influence on immunological processes in patients with cardiovascular pathology allows to expand the range of diagnostic and prognostic criteria for the formation of immuno-inflammatory reactions and endothelial dysfunction and to outline ways to personify the choice of therapeutic programs, which, in turn, can open approaches to develop fundamentally newer pharmaceuticals.

Abstract 1792: Engineered exosome- mediated STAT6 knockdown in tumor associated macrophages (TAMs) results in potent single agent activity in a hepatocellular carcinoma (HCC) model

Abstract Background: Tumor-associated macrophages (TAMs) promote tumor progression and resistance to immune checkpoint inhibitors and are thus attractive targets for cancer immunotherapy. The STAT6 transcriptional network is an important driver of the immune-suppressive M2 macrophage program in the tumor microenvironment (TME). Previous attempts to therapeutically target these transcriptional networks have not been successful. Exosomes serve as an efficient, natural, intercellular communication system that can deliver nucleic acids and other macromolecules. Leveraging the potential of exosomes, we have developed a novel, engineered exosome therapeutic candidate loaded with antisense oligonucleotides (ASO) targeting STAT6 (exoASO-STAT6), that effectively silences STAT6 expression in TAMs. Results: In vitro and in vivo studies demonstrate an enhanced delivery of ASO to M2 macrophages. exoASO showed a 2x improvement in uptake vs free ASO in human M2 macrophages in vitro. Following IV administration, exoASO demonstrated up to 11x increase in uptake in monocytes and MDSCs in the blood, Kupffer cells in liver and TAMs and MDSCs in the tumor. In vitro treatment with exoASO-STAT6 resulted in 90% target gene KD in human, mouse and cynomolgus monkey M2 macrophages, which was persistent for up to 10 days. Additionally, exoASO-STAT6 demonstrated greater potency than free ASO. STAT6 KD resulted in a 7x decrease in M2 marker CD163 and a 25x increase in pro-inflammatory cytokines such as IL-12 or TNFα, demonstrating effective macrophage reprogramming. In vivo efficacy studies in CT26 showed potent dose-dependent single agent activity of exoASO-STAT6, with a cumulative dose of 36 μg of ASO resulting in 94% TGI and 80% complete responses. CD8 T-cell depletion abrogated anti-tumor activity and the complete responders were resistant to tumor cell re-challenge, demonstrating a CD8-T cell mediated immunological memory response. In an orthotopic model of HCC that is resistant to anti-PD-1 or anti-CSF1R therapy, IV administration of exoASO-STAT6 significantly attenuated tumor growth, as observed by a 61% reduction in tumor mass and complete elimination of tumor lesions in 50% of treated mice. exoASO-STAT6 therapy resulted in a decrease in M2 markers such as Tgfb1 and Ccl17 and an increase in M1 markers such as IL1b. A significant increase in interferon and cytotoxic T-cell gene signatures was also observed, demonstrating effective reprogramming of the TME. Conclusion: exoASO-STAT6 is a novel therapeutic that selectively targets STAT6, a key transcription factor in TAMs. This therapy results in effective macrophage reprogramming to a pro-inflammatory M1 phenotype and potent single agent anti-tumor activity in multiple checkpoint refractory tumor models. In sum, exoASO-STAT6 represents a first-in-class strategy to target TAMs in a highly selective manner. Citation Format: Sushrut Kamerkar, Charan Leng, Olga Burenkova, Su Chul Jang, Christine McCoy, Kelvin Zhang, William Dahlberg, Marie Leblanc, Hugo Quillery, Sylvie Maubant, Olivier Duchamp, Kyriakos Economides, Timothy Soos, Dalia Burzyn, Sriram Sathyanarayanan. Engineered exosome- mediated STAT6 knockdown in tumor associated macrophages (TAMs) results in potent single agent activity in a hepatocellular carcinoma (HCC) model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1792.