Exosome-Based COVID-19 Vaccine.

Extracellular vesicles (EVs) enable cell-to-cell communication and, by delivering antigens, can stimulate the immune response strongly. Approved in use SARS-CoV-2 vaccine, candidates immunize with the viral spike protein delivered via viral vectors, translated by injected mRNAs, or as a pure protein. Here, we outline a novel methodological approach for generating SARS-CoV-2 vaccine using exosome that delivers antigens from the SARS-CoV-2 structural proteins. Engineered EVs can be loaded with viral antigens, thus acting as antigens presenting EVs, eliciting strong and targeted CD8(+) T cell and B cell, offering a unique approach to vaccine development. Engineered EVs thus portray a safe, adaptable, and effective approach for a virus-free vaccine development.

Exosome-Based Multivalent Vaccine: Achieving Potent Immunization, Broadened Reactivity, and Strong T-Cell Responses with Nanograms of Proteins.

Currently approved vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have focused solely on the spike protein to provide immunity. The first vaccines were developed rapidly using spike mRNA delivered by lipid nanoparticles but required ultralow-temperature storage and have had limited immunity against variations in spike. Subsequently, protein-based vaccines were developed, which offer broader immunity but require significant time for development and the use of an adjuvant to boost the immune response. Here, exosomes were used to deliver a bivalent protein-based vaccine in which two independent viral proteins were used. Exosomes were engineered to express either SARS-CoV-2 delta spike (Stealth X-Spike [STX-S]) or the more conserved nucleocapsid (Stealth X-Nucleocapsid [STX-N]) protein on the surface. When administered as a single product (STX-S or STX-N) or in combination (STX-S+N), both STX-S and STX-N induced strong immunization with the production of potent humoral and cellular immune responses. Interestingly, these results were obtained with the administration of only nanograms of protein and without an adjuvant. In two independent animal models (mouse and rabbit), the administration of nanograms of the STX-S+N vaccine resulted in increased antibody production, potent neutralizing antibodies with cross-reactivity to other variants of spike, and strong T-cell responses. Importantly, no competition of immune responses was observed, allowing the delivery of nucleocapsid with spike to offer improved SARS-CoV-2 immunity. These data show that the StealthX exosome platform has the enormous potential to revolutionize vaccinology by combining the advantages of mRNA and recombinant protein vaccines into a superior, rapidly generated, low-dose vaccine resulting in potent, broader immunity. IMPORTANCE The pandemic emergency has brought to light the need for a new generation of rapidly developed vaccines that induce longer-lasting, potent, and broader immune responses. While the mRNA vaccines played a critical role during the emergency in reducing SARS-CoV-2 hospitalization rates and deaths, more efficient approaches are needed. A multivalent, protein-based vaccine delivered by exosomes could meet this urgent need due to the high speed of development, manufacturability, and the ability to produce a strong antibody response, with neutralizing antibodies and a strong T-cell response able to broadly combat viral infection with a minimum number of injections.

Exosome and virus infection.

Exosomes are messengers of intercellular communication in monolayer vesicles derived from cells. It affects the pathophysiological process of the body in various diseases, such as tumors, inflammation, and infection. It has been confirmed that exosomes are similar to viruses in biogenesis, and exosome cargo is widely involved in many viruses' replication, transmission, and infection. Simultaneously, virus-associated exosomes can promote immune escape and activate the antiviral immune response of the body, which bidirectionally modulates the immune response. This review focuses on the role of exosomes in HIV, HBV, HCV, and SARS-CoV-2 infection and explores the prospects of exosome development. These insights may be translated into therapeutic measures for viral infections and reduce the disease burden.

Cardiovascular Disease as a Consequence or a Cause of Cancer: Potential Role of Extracellular Vesicles.

Both cardiovascular disease and cancer continue to be causes of morbidity and mortality all over the world. Preventing and treating heart disease in patients undergoing cancer treatment remain an important and ongoing challenge for improving the lives of cancer patients, but also for their survival. Despite ongoing efforts to improve patient survival, minimal advances have been made in the early detection of cardiovascular disease in patients suffering from cancer. Understanding the communication between cancer and cardiovascular disease can be based on a deeper knowledge of the molecular mechanisms that define the profile of the bilateral network and establish disease-specific biomarkers and therapeutic targets. The role of exosomes, microvesicles, and apoptotic bodies, together defined as extracellular vesicles (EVs), in cross talk between cardiovascular disease and cancer is in an incipient form of research. Here, we will discuss the preclinical evidence on the bilateral connection between cancer and cardiovascular disease (especially early cardiac changes) through some specific mediators such as EVs. Investigating EV-based biomarkers and therapies may uncover the responsible mechanisms, detect the early stages of cardiovascular damage and elucidate novel therapeutic approaches. The ultimate goal is to reduce the burden of cardiovascular diseases by improving the standard of care in oncological patients treated with anticancer drugs or radiotherapy.

Emerging role of mesenchymal stem/stromal cells (MSCs) and MSCs-derived exosomes in bone- and joint-associated musculoskeletal disorders: a new frontier.

Exosomes are membranous vesicles with a 30 to 150 nm diameter secreted by mesenchymal stem/stromal cells (MSCs) and other cells, such as immune cells and cancer cells. Exosomes convey proteins, bioactive lipids, and genetic components to recipient cells, such as microRNAs (miRNAs). Consequently, they have been implicated in regulating intercellular communication mediators under physiological and pathological circumstances. Exosomes therapy as a cell-free approach bypasses many concerns regarding the therapeutic application of stem/stromal cells, including undesirable proliferation, heterogeneity, and immunogenic effects. Indeed, exosomes have become a promising strategy to treat human diseases, particularly bone- and joint-associated musculoskeletal disorders, because of their characteristics, such as potentiated stability in circulation, biocompatibility, low immunogenicity, and toxicity. In this light, a diversity of studies have indicated that inhibiting inflammation, inducing angiogenesis, provoking osteoblast and chondrocyte proliferation and migration, and negative regulation of matrix-degrading enzymes result in bone and cartilage recovery upon administration of MSCs-derived exosomes. Notwithstanding, insufficient quantity of isolated exosomes, lack of reliable potency test, and exosomes heterogeneity hurdle their application in clinics. Herein, we will deliver an outline respecting the advantages of MSCs-derived exosomes-based therapy in common bone- and joint-associated musculoskeletal disorders. Moreover, we will have a glimpse the underlying mechanism behind the MSCs-elicited therapeutic merits in these conditions.

The emerging role of exosomes in innate immunity, diagnosis and therapy.

Exosomes, which are nano-sized transport bio-vehicles, play a pivotal role in maintaining homeostasis by exchanging genetic or metabolic information between different cells. Exosomes can also play a vital role in transferring virulent factors between the host and parasite, thereby regulating host gene expression and the immune interphase. The association of inflammation with disease development and the potential of exosomes to enhance or mitigate inflammatory pathways support the notion that exosomes have the potential to alter the course of a disease. Clinical trials exploring the role of exosomes in cancer, osteoporosis, and renal, neurological, and pulmonary disorders are currently underway. Notably, the information available on the signatory efficacy of exosomes in immune-related disorders remains elusive and sporadic. In this review, we discuss immune cell-derived exosomes and their application in immunotherapy, including those against autoimmune connective tissue diseases. Further, we have elucidated our views on the major issues in immune-related pathophysiological processes. Therefore, the information presented in this review highlights the role of exosomes as promising strategies and clinical tools for immune regulation.

Porcine Hemagglutinating Encephalomyelitis Virus Co-Opts Multivesicular-Derived Exosomes for Transmission.

Porcine hemagglutinating encephalomyelitis virus (PHEV) is a member of the family Coronaviridae, genus Betacoronavirus, and subgenus Embecovirus that causes neurological disorders, vomiting and wasting disease (VWD), or influenza-like illness (ILI) in pigs. Exosomes regulate nearby or distant cells as a means of intercellular communication; however, whether they are involved in the transmission of viral reference materials during PHEV infection is unknown. Here, we collected exosomes derived from PHEV-infected neural cells (PHEV-exos) and validated their morphological, structural, and content characteristics. High-resolution mass spectrometry indicated that PHEV-exos carry a variety of cargoes, including host innate immunity sensors and viral ingredients. Furthermore, transwell analysis revealed that viral ingredients, such as proteins and RNA fragments, could be encapsulated in the exosomes of multivesicular bodies (MVBs) to nonpermissive microglia. Inhibition of exosome secretion could suppress PHEV infection. Therefore, we concluded that the mode of infectious transmission of PHEV is likely through a mixture of virus-modified exosomes and virions and that exosomal export acts as a host strategy to induce an innate response in replicating nonpermissive bystander cells free of immune system recognition. IMPORTANCE The novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a large number of deaths worldwide. Clinical neurological complications have occurred in some cases; however, knowledge of the natural history of coronavirus in the central nervous system (CNS) is thus far limited. PHEV is a typical neurotropic betacoronavirus (ß-CoV) that propagates via neural circuits in the host CNS after peripheral incubation rather than through the bloodstream. It is therefore a good prototype pathogen to investigate the neuropathological pathogenesis of acute human coronavirus infection. In this study, we demonstrate a new association between host vesicle-based secretion and PHEV infection, showing that multivesicular-derived exosomes are one of the modes of infectious transmission and that they mediate the transfer of immunostimulatory cargo to uninfected neuroimmune cells. These findings provide novel insights into the treatment and monitoring of neurological consequences associated with ß-CoV, similar to those associated with SARS-CoV-2.

Challenges and strategies: Scalable and efficient production of mesenchymal stem cells-derived exosomes for cell-free therapy.

Exosomes are small membrane vesicles secreted by most cell types, and widely exist in cell supernatants and various body fluids. They can transmit numerous bioactive elements, such as proteins, nucleic acids, and lipids, to affect the gene expression and function of recipient cells. Mesenchymal stem cells (MSCs) have been confirmed to be a potentially promising therapy for tissue repair and regeneration. Accumulating studies demonstrated that the predominant regenerative paradigm of MSCs transplantation was the paracrine effect but not the differentiation effect. Exosomes secreted by MSCs also showed similar therapeutic effects as their parent cells and were considered to be used for cell-free regenerative medicine. However, the inefficient and limited production has hampered their development for clinical translation. In this review, we summarize potential methods to efficiently promote the yield of exosomes. We mainly focus on engineering the process of exosome biogenesis and secretion, altering the cell culture conditions, cell expansion through 3D dynamic culture and the isolation of exosomes. In addition, we also discuss the application of MSCs-derived exosomes as therapeutics in disease treatment.

SARS CoV-2 spike protein-guided exosome isolation facilitates detection of potential miRNA biomarkers in COVID-19 infections.

OBJECTIVES: Nearly three years into the pandemic, SARS-CoV-2 infections are occurring in vaccinated and naturally infected populations. While humoral and cellular responses in COVID-19 are being characterized, novel immune biomarkers also being identified. Recently, an increase in angiotensin-converting enzyme 2 expressing (aka, ACE2 positive) circulating exosomes (ExoACE2) were identified in the plasma of COVID-19 patients (El-Shennawy et al.). In this pilot study, we describe a method to characterize the exosome-associated microRNA (exo-miRNA) signature in ACE2-positive and ACE2-negative exosomal populations (non-ExoACE2). METHODS: We performed a sorting protocol using the recombinant biotin-conjugated SARS CoV-2 spike protein containing the receptor binding domain (RBD) on plasma samples from six patients. Following purification, exo-miRNA were characterized for ACE2-positive and ACE2-negative exosome subpopulations by RT-PCR. RESULTS: We identified differential expression of several miRNA. Specifically let-7g-5p and hsa-miR-4454+miR-7975 were upregulated, while hsa-miR-208a-3p and has-miR-323-3p were downregulated in ExoACE2 vs. non-ExoACE2. CONCLUSIONS: The SARS CoV-2 spike-protein guided exosome isolation permits isolation of ExoACE2 exosomes. Such purification facilitates detailed characterization of potential biomarkers (e.g. exo-miRNA) for COVID-19 patients. This method could be used for future studies to further the understanding mechanisms of host response against SARS CoV-2.

Roles and mechanisms of exosomal microRNAs in viral infections.

Exosomes are small extracellular vesicles with a diameter of 30-150 nm that originate from endosomes and fuse with the plasma membrane. They are secreted by almost all kinds of cells and can stably transfer different kinds of cargo from donor to recipient cells, thereby altering cellular functions for assisting cell-to-cell communication. Exosomes derived from virus-infected cells during viral infections are likely to contain different microRNAs (miRNAs) that can be transferred to recipient cells. Exosomes can either promote or suppress viral infections and therefore play a dual role in viral infection. In this review, we summarize the current knowledge about the role of exosomal miRNAs during infection by six important viruses (hepatitis C virus, enterovirus A71, Epstein-Barr virus, human immunodeficiency virus, severe acute respiratory syndrome coronavirus 2, and Zika virus), each of which causes a significant global public health problem. We describe how these exosomal miRNAs, including both donor-cell-derived and virus-encoded miRNAs, modulate the functions of the recipient cell. Lastly, we briefly discuss their potential value for the diagnosis and treatment of viral infections.

Exosomes in COVID-19 infection: Focus on role in diagnosis, pathogenesis, immunity, and clinical trials.

Since the end of 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread as a new strain of coronavirus disease (COVID-19) and progressed as a global pandemic. Exosomes are membrane-bound vesicles released from almost all cells and are crucially involved in cell-cell communication. Interestingly, COVID-19 viral particles produce exosomes that moderate communication between infected and uninfected cells. Hence, there is growing evidence highlighting the crucial implications of exosomes in COVID-19 infection, transmission, intercellular spread, and reinfection. On the other hand, clinical trials have demonstrated mesenchymal stem cell-derived exosomes as a promising therapeutic strategy for severely affected COVID-19 patients. Also, convalescent plasma-derived exosomes have been proposed for multiple efficacies in COVID-19 patients. Furthermore, messenger RNAs (mRNA)-loaded exosomes were superior to mRNA-loaded lipid nanoparticles as a delivery system. Hence, exosomes can be used to safely induce SARS-CoV-2 immunity via their loading with mRNAs encoding immunogenic forms of SARS-CoV-2 spike and nucleocapsid proteins. Moreover, exosomes can be used as a nano-delivery system for microRNA to alleviate cytokine storm and prevent the progression of organ failure in COVID-19 patients. The present review summarizes state of the art concerning the role of exosomes in COVID-19 infection and accompanying organ complications as well as the potential use of exosomes in COVID-19 diagnosis, treatment, drug delivery, and vaccination. The review also sheds the light on the common biogenic pathway between the SARS-CoV-2 virus and exosomes. Additionally, the latest and current clinical trials using exosomes for COVID-19 infection are summarized.

A pilot study for treatment of severe COVID-19 pneumonia by aerosolized formulation of convalescent human immune plasma exosomes (ChipEXO™).

This is a single-center prospective, open-label, single arm interventional study to test the safety and efficacy of recently described ChipEXO™ for severe COVID-19 pneumonia. The ChipEXO™ is a natural product derived from convalescent human immune plasma of patients recovered from moderate COVID-19 infection. In September 2021, 13 patients with pending respiratory failure were treated with ChipEXO™ adapted for aerosolized formulation delivered via jet nebulizer. Patients received 1-5x1010 nano vesicle/5 mL in distilled water twice daily for five days as an add-on to ongoing conventional COVID-19 treatment. The primary endpoint was patient safety and survival over a 28-day follow-up. The secondary endpoint was longitudinal assessment of clinical parameters following ChipEXO™ to evaluate treatment response and gain insights into the pharmacodynamics. ChipEXO™ was tolerated well without any allergic reaction or acute toxicity. The survival rate was 84.6% and 11 out of 13 recovered without any sequel to lungs or other organs. ChipEXO™ treatment was effective immediately as shown in arterial blood gas analyses before and two hours after exosome inhalation. During the 5 days of treatment, there was a sustainable and gradual improvement on oxygenation parameters: i.e. respiratory rate (RR) [20.8% (P < 0.05)], oxygen saturation (SpO2) [6,7% (P < 0.05)] and partial pressure of oxygen to the fraction of inspired oxygen (PaO2/FiO2) [127.9% (P < 0.05)] that correlated with steep decrease in the disease activity scores and inflammatory markers, i.e. the sequential organ failure assessment (SOFA) score (75%, p < 0.05), C-reactive protein (46% p < 0.05), ferritin (58% p = 0.53), D-dimer (28% p=0.46). In conclusion, aerosolized ChipEXO™ showed promising safety and efficacy for life-threatening COVID-19 pneumonia. Further studies on larger patient populations are required to confirm our findings and understand the pathophysiology of improvement toward a new therapeutic agent for the treatment of severe COVID-19 pneumonia.

Extracellular Vesicles of COVID-19 Patients Reflect Inflammation, Thrombogenicity, and Disease Severity.

Severe COVID-19 infections present with cytokine storms, hypercoagulation, and acute respiratory distress syndrome, with extracellular vesicles (EVs) being involved in coagulation and inflammation. This study aimed to determine whether coagulation profiles and EVs reflect COVID-19 disease severity. Thirty-six patients with symptomatic COVID-19 infection with mild/moderate/severe disease (12 in each group) were analyzed. Sixteen healthy individuals served as controls. Coagulation profiles and EV characteristics were tested by nanoparticle tracking analysis (NTA), flow cytometry, and Western blot. While coagulation factors VII, V, VIII, and vWF were comparable, significant differences were found in patients' D-Dimer/fibrinogen/free protein S levels compared to controls. Severe patients' EVs displayed higher percentages of small EVs (<150 nm) with increased expression of exosome marker CD63. Severe patients' EVs displayed high levels of platelet markers (CD41) and coagulation factors (tissue factor activity, endothelial protein C receptor). EVs of patients with moderate/severe disease expressed significantly higher levels of immune cell markers (CD4/CD8/CD14) and contained higher levels of IL-6. We demonstrated that EVs, but not the coagulation profile, may serve as biomarkers for COVID-19 severity. EVs demonstrated elevated levels of immune- and vascular-related markers in patients with moderate/severe disease, and may play a role in disease pathogenesis.

COVID-19 plasma exosomes promote proinflammatory immune responses in peripheral blood mononuclear cells.

Elevated serum cytokine production in COVID-19 patients is associated with disease progression and severity. However, the stimuli that initiate cytokine production in patients remain to be fully revealed. Virus-infected cells release virus-associated exosomes, extracellular vesicles of endocytic origin, into the blood to deliver viral cargoes able to regulate immune responses. Here, we report that plasma exosomes of COVID-19 patients contain SARS-CoV-2 double stranded RNA (dsRNA) and stimulate robust production of interleukin-6 (IL-6), IL-8, tumor necrosis factor-α (TNF-α), and other inflammatory cytokines and chemokines by human peripheral mononuclear cells. Exosome depletion abolished these stimulated responses. COVID-19 plasma exosomes induced proinflammatory responses in CD4+ T cells, CD8+ T cells, and CD14+ monocytes but not significantly in regulatory T cells, Th17 T cells, or central memory T cells. COVID-19 plasma exosomes protect the SARS-CoV-2 dsRNA cargo from RNase and deliver the dsRNA into recipient cells. These exosomes significantly increase expression of endosomal toll-like receptor 3 (TLR3), TLR7, TLR8, and TLR9 in peripheral T cells and monocytes. A pharmacological inhibitor of TLR3 considerably reduced cytokine and chemokine production by CD4+ and CD8+ T cells but not by CD14+ monocytes, highlighting divergent signaling pathways of immune cells in response to COVID-19 plasma exosomes. Our results identify a novel model of intercellular crosstalk following SARS-CoV-2 infection that evoke immune responses positioned to contribute to elevated cytokine production associated with COVID-19 progression, severity, and long-haul symptoms.

Anticarcinogenic impact of extracellular vesicles (exosomes) from cord blood stem cells in malignant melanoma: A potential biological treatment.

Incidence of Malignant Melanoma has become the 5th in the UK. To date, the major anticancer therapeutics include cell therapy, immunotherapy, gene therapy and nanotechnology-based strategies. Recently, extracellular vesicles, especially exosomes, have been highlighted for their therapeutic benefits in numerous chronic diseases. Exosomes display multifunctional properties, including inhibition of cancer cell proliferation and initiation of apoptosis. In the present in vitro study, the antitumour effect of cord blood stem cell (CBSC)-derived exosomes was confirmed by the CCK-8 assay (p < 0.05) on CHL-1 melanoma cells and improve the repair mechanism on lymphocytes from melanoma patients. Importantly, no significant effect was observed in healthy lymphocytes when treated with the exosome concentrations at 24, 48 and 72 h. Comet assay results (OTM and %Tail DNA) demonstrated that the optimal exosome concentration showed a significant impact (p < 0.05) in lymphocytes from melanoma patients whilst causing no significant DNA damage in lymphocytes of healthy volunteers was 300 µg/ml. Similarly, the Comet assay results depicted significant DNA damage in a melanoma cell line (CHL-1 cells) treated with CBSC-derived exosomes, both the cytotoxicity of CHL-1 cells treated with CBSC-derived exosomes exhibited a significant time-dependent decrease in cell survival. Sequencing analysis of CBSC exosomes showed the presence of the let-7 family of miRNAs, including let-7a-5p, let-7b-5p, let-7c-5p, let-7d-3p, let-7d-5p and two novel miRNAs. The potency of CBSC exosomes in inhibiting cancer progression in lymphocytes from melanoma patients and CHL-1 cells whilst causing no harm to the healthy lymphocytes makes it a potential candidate as an anticancer therapy.

The Role of Exosomes in Health and Disease.

Who would have thought that the discovery made by researchers at Washington University [...].

SARS-CoV-2 takes the bait: Exosomes as endogenous decoys.

Writing in PLOS Biology, Ching and colleagues show that ACE2-decorated exosomes are deployed as natural inhibitory decoys against SARS-CoV-2. High decoy levels correlate with improved patient outcomes, suggesting they directly help COVID-19 recovery and supporting the concept of successful future decoy-based therapies.

Exosome Proteomics Reveals the Deregulation of Coagulation, Complement and Lipid Metabolism Proteins in Gestational Diabetes Mellitus.

Exosomes are small extracellular vesicles with a variable protein cargo in consonance with cell origin and pathophysiological conditions. Gestational diabetes mellitus (GDM) is characterized by different levels of chronic low-grade inflammation and vascular dysfunction; however, there are few data characterizing the serum exosomal protein cargo of GDM patients and associated signaling pathways. Eighteen pregnant women were enrolled in the study: 8 controls (CG) and 10 patients with GDM. Blood samples were collected from patients, for exosomes' concentration. Protein abundance alterations were demonstrated by relative mass spectrometric analysis and their association with clinical parameters in GDM patients was performed using Pearson's correlation analysis. The proteomics analysis revealed 78 significantly altered proteins when comparing GDM to CG, related to complement and coagulation cascades, platelet activation, prothrombotic factors and cholesterol metabolism. Down-regulation of Complement C3 (C3), Complement C5 (C5), C4-B (C4B), C4b-binding protein beta chain (C4BPB) and C4b-binding protein alpha chain (C4BPA), and up-regulation of C7, C9 and F12 were found in GDM. Our data indicated significant correlations between factors involved in the pathogenesis of GDM and clinical parameters that may improve the understanding of GDM pathophysiology. Data are available via ProteomeXchange with identifier PXD035673.

Correlation of alpha-1 antitrypsin levels and exosome associated neutrophil elastase endothelial injury in subjects with SARS-CoV2 infection.

BACKGROUND: Severe acute respiratory syndrome caused by a novel coronavirus 2 (SARS-CoV-2) has infected more than 18 million people worldwide. The activation of endothelial cells is a hallmark of signs of SARS-CoV-2 infection that includes altered integrity of vessel barrier and endothelial inflammation. OBJECTIVES: Pulmonary endothelial activation is suggested to be related to the profound neutrophil elastase (NE) activity, which is necessary for sterilization of phagocytosed bacterial pathogens. However, unopposed activity of NE increases alveolocapillary permeability and extracellular matrix degradation. The uncontrolled protease activity of NE during the inflammatory phase of lung diseases might be due to the resistance of exosome associated NE to inhibition by alpha-1 antitrypsin. METHOD: 31 subjects with a diagnosis of SARS-CoV2 infection were recruited in the disease group and samples from 30 voluntaries matched for age and sex were also collected for control. RESULTS: We measured the plasma levels of exosome-associated NE in SARS-CoV-2 patients which, were positively correlated with sign of endothelial damage in those patients as determined by plasma levels of LDH. Notably, we also found strong correlation with plasma levels of alpha-1 antitrypsin and exosome-associated NE in SARS-CoV-2 patients. Using macrovascular endothelial cells, we also observed that purified NE activity is inhibited by purified alpha-1 antitrypsin while, NE associated with exosomes are resistant to inhibition and show less sensitivity to alpha-1 antitrypsin inhibitory activity, in vitro. CONCLUSIONS: Our results point out the role of exosome-associated NE in exacerbation of endothelial injury in SARS-CoV-2 infection. We have demonstrated that exosome-associated NE could be served as a new potential therapeutic target of severe systemic manifestations of SARS-CoV-2 infection.

Interrelation between extracellular vesicles miRNAs with chronic lung diseases.

Extracellular vehicles (EVs) are nanoscale lipid bilayer vesicles that carry biologically active biomolecule cargos like proteins, lipids, and nucleic acids (DNA, RNA) outside of the cell. Blood (serum/plasma), urine, and bronchoalveolar lavage fluid are all examples of biofluids from which they may be collected. EVs play a vital role in intracellular communication. The molecular signature of EVs largely depends on the parental cell's status. EVs are classified into two groups, (1) exosomes (originated by endogenous route) and (2) microvesicles (originated from the plasma membrane, also known as ectosomes). The quantity and types of EV cargo vary during normal conditions compared to pathological conditions (chronic inflammatory lung diseases or lung cancer). Consequently, EVs contain novel biomarkers that differ based on the cell type of origin and during lung diseases. Small RNAs (e.g., microRNAs) are transported by EVs, which is one of the most rapidly evolving research areas in the field of EVs biology. EV-mediated cargos transport small RNAs that can result in reprograming the target/recipient cells. Multiple chronic inflammatory lung illnesses, such as chronic obstructive pulmonary disease, asthma, pulmonary hypertension, pulmonary fibrosis, cystic fibrosis, acute lung injury, and lung cancer, have been demonstrated to be regulated by EV. In this review, we will consolidate the current knowledge and literature on the novel role of EVs and their small RNAs concerning chronic lung diseases (CLDs). Additionally, we will also provide better insight into the clinical and translational impact of mesenchymal stem cells-derived EVs as novel therapeutic agents in treating CLDs.