PMID: 

Emerg Microbes Infect. 2019 ;8(1):307-326. PMID: 30866785

Abstract Title: 

Exosomes mediate Zika virus transmission through SMPD3 neutral Sphingomyelinase in cortical neurons.

Abstract: 

The harmful effects of ZIKA virus (ZIKV) infection are reflected by severe neurological manifestations such as microcephaly in neonates and other complications associated with Guillain-Barré syndrome in adults. The transmission dynamics of ZIKV in or between neurons, or within the developing brains of the foetuses are not fully understood. Using primary cultures of murine cortical neurons, we show that ZIKV uses exosomes as mediators of viral transmission between neurons. Cryo-electron microscopy showed heterogeneous population of neuronal exosomes with a size range of 30-200 nm. Increased production of exosomes from neuronal cells was noted upon ZIKV infection. Neuronal exosomes contained both ZIKV viral RNA and protein(s) that were highly infectious to naïve cells. RNaseAand neutralizing antibodies treatment studies suggest the presence of viral RNA/proteins inside exosomes. Exosomes derived from time- and dose-dependent incubations showed increasing viral loads suggesting higher packaging and delivery of ZIKV RNA and proteins. Furthermore, we noted that ZIKV induced both activity and gene expression of neutral Sphingomyelinase (nSMase)-2/SMPD3, an important molecule that regulates production and release of exosomes. Silencing of SMPD3 in neurons resulted in reduced viral burden and transmission through exosomes. Treatment with SMPD3 specific inhibitor GW4869,significantly reduced ZIKV loads in both cortical neurons and in exosomes derived from these neuronal cells. Taken together, our results suggest that ZIKV modulates SMPD3 activity in cortical neurons for its infection and transmission through exosomes perhaps leading to severe neuronal death that may result in neurological manifestations such as microcephaly in the developing embryonic brains.

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PMID: 

Biomed Res Int. 2019 ;2019:2103943. Epub 2019 May 28. PMID: 31275965

Abstract Title: 

Exosomes Modulate the Viral Replication and Host Immune Responses in HBV Infection.

Abstract: 

Although current diagnosis and treatment of hepatitis B virus (HBV) infection can maintain viral suppression, new therapies need to be invented to sustain off-treatment virologic suppression and reduce side effects. Exosomes act as intercellular communicators to facilitate direct transfer of proteins, lipids, and nucleic acids between cellsand. Pioneering work has demonstrated that exosomal cargos changed markedly during HBV infection. An improved understanding of the functions of exosomes during HBV infection could lead to a powerful new strategy for preventing and treating HBV. In this review, we point out the role of exosomes in HBV infection: (1) exosomes could directly participate in HBV replication; (2) exosomes modulate immune response during HBV infections; (3) exosomal RNAs and proteins might be selected as novel biomarkers for the diagnosis of HBV infections; and (4) exosomes can also be designed as vaccines.

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PMID: 

Sci Adv. 2019 07 ;5(7):eaav3270. Epub 2019 Jul 17. PMID: 31328155

Abstract Title: 

Excessive exosome release is the pathogenic pathway linking a lysosomal deficiency to generalized fibrosis.

Abstract: 

Lysosomal exocytosis is a ubiquitous process negatively regulated by neuraminidase 1 (NEU1), a sialidase mutated in the glycoprotein storage disease sialidosis. Inmice, excessive lysosomal exocytosis is at the basis of disease pathogenesis. Yet, the tissue-specific molecular consequences of this deregulated pathway are still unfolding. We now report that in muscle connective tissue,fibroblasts have features of myofibroblasts and are proliferative, migratory, and exocytose large amounts of exosomes. These nanocarriers loaded with activated transforming growth factor-β and wingless-related integration site (WNT)/β-catenin signaling molecules propagate fibrotic signals to other cells, maintaining the tissue in a prolonged transitional status. Myofibroblast-derived exosomes fed to normal fibroblasts convert them into myofibroblasts, changing the recipient cells'proliferative and migratory properties. These findings reveal an unexpected exosome-mediated signaling pathway downstream of NEU1 deficiency that propagates a fibrotic disease and could be implicated in idiopathic forms of fibrosis in humans.

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Sayer Ji appears on the Robert Phoenix show and breaks down the social, psychic and health challenges of the current lockdown and state of the Coronavirus crisis.

Take action and join a community who cares about health freedom: https://www.standforhealthfreedom.com

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PMID: 

PLoS Pathog. 2019 07 ;15(7):e1007907. Epub 2019 Jul 25. PMID: 31344124

Abstract Title: 

Exosomes containing HIV protein Nef reorganize lipid rafts potentiating inflammatory response in bystander cells.

Abstract: 

HIV infection has a profound effect on"bystander"cells causing metabolic co-morbidities. This may be mediated by exosomes secreted by HIV-infected cells and containing viral factors. Here we show that exosomes containing HIV-1 protein Nef (exNef) are rapidly taken up by macrophages releasing Nef into the cell interior. This caused down-regulation of ABCA1, reduction of cholesterol efflux and sharp elevation of the abundance of lipid rafts through reduced activation of small GTPase Cdc42 and decreased actin polymerization. Changes in rafts led to re-localization of TLR4 and TREM-1 to rafts, phosphorylation of ERK1/2, activation of NLRP3 inflammasome, and increased secretion of pro-inflammatory cytokines. The effects of exNef on lipid rafts and on inflammation were reversed by overexpression of a constitutively active mutant of Cdc42. Similar effects were observed in macrophages treated with exosomes produced by HIV-infected cells or isolated from plasma of HIV-infected subjects, but not with exosomes from cells and subjects infected withΔNef-HIV or uninfected subjects. Mice injected with exNef exhibited monocytosis, reduced ABCA1 in macrophages, increased raft abundance in monocytes and augmented inflammation. Thus, Nef-containing exosomes potentiated pro-inflammatory response by inducing changes in cholesterol metabolism and reorganizing lipid rafts. These mechanisms may contribute to HIV-associated metabolic co-morbidities.

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PMID: 

J Biomed Sci. 2019 Aug 15 ;26(1):58. Epub 2019 Aug 15. PMID: 31416454

Abstract Title: 

Exosome-delivered and Y RNA-derived small RNA suppresses influenza virus replication.

Abstract: 

BACKGROUND: Multiple interplays between viral and host factors are involved in influenza virus replication and pathogenesis. Several small RNAs have recently emerged as important regulators of host response to viral infections. The aim of this study was to characterize the functional role of hsa-miR-1975, a Y5 RNA-derived small RNA, in defending influenza virus and delineate the mechanisms.METHODS: We performed high throughput sequencing of small RNAs in influenza virus-infected cells to identify up- or down- regulated small RNA species. The expression of the most abundant RNA species (hsa-miR-1975) was validated by stem-loop reverse transcription-polymerase chain reaction (RT-PCR). Antiviral effects of hsa-miR-1975 were confirmed by Western Blot, RT-PCR and plaque assay. In vitro perturbation of hsa-miR-1975 combined with exosomes isolation was used to elucidate the role and mechanism of hsa-miR-1975 in the context of antiviral immunity.RESULTS: Small RNA sequencing revealed that hsa-miR-1975 was the most up-regulated small RNA in influenza virus-infected cells. The amount of intracellular hsa-miR-1975 increased in the late stage of the influenza virus replication cycle. The increased hsa-miR-1975 was at least partially derived from degradation of Y5RNA as a result of cellular apoptosis. Unexpectedly, hsa-miR-1975 mimics inhibited influenza virus replication while hsa-miR-1975 sponges enhanced the virus replication. Moreover, hsa-miR-1975 was secreted in exosomes and taken up by the neighboring cells to induce interferon expression.CONCLUSIONS: Our findings unravel a critical role of Y-class small RNA in host's defense against influenza virus infection and reveal its antiviral mechanism through exosome delivery. This may provide a new candidate for targeting influenza virus.

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PMID: 

Int J Cancer. 2020 01 15 ;146(2):305-320. Epub 2019 Oct 31. PMID: 31566705

Abstract Title: 

Pathogenic role of exosomes and microRNAs in HPV-mediated inflammation and cervical cancer: A review.

Abstract: 

Cervical cancer (CC) is the fourth most common cause of cancer death in women. The most important risk factor for the development of CC is cervical infection with human papilloma virus (HPV). Inflammation is a protective strategy that is triggered by the host against pathogens such as viral infections that acts rapidly to activate the innate immune response. Inflammation is beneficial if it is brief and well controlled; however, if the inflammation is excessive or it becomes of chronic duration, it can produce detrimental effects. HPV proteins are involved, both directly and indirectly, in the development of chronic inflammation, which is a causal factor in the development of CC. However, other factors may also have a potential role in stimulating chronic inflammation. MicroRNAs (miRNAs) (a class of noncoding RNAs) are strong regulators of gene expression. They have emerged as key players in several biological processes, including inflammatory pathways. Abnormal expression of miRNAs may be linked to the induction of inflammation that occurs in CC. Exosomes are a subset of extracellular vesicles shed by almost all types of cells, which can function as cargo transfer vehicles. Exosomes contain proteins and genetic material (including miRNAs) derived from their parent cells and can potentially affect recipient cells. Exosomes have recently been recognized to be involved in inflammatory processes and can also affect the immune response. In this review, we discuss the role of HPV proteins, miRNAs and exosomes in the inflammation associated with CC.

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PMID: 

Biomedicines. 2019 Nov 3 ;7(4). Epub 2019 Nov 3. PMID: 31684167

Abstract Title: 

Circulating Exosomal miRNA Profiles Predict the Occurrence and Recurrence of Hepatocellular Carcinoma in Patients with Direct-Acting Antiviral-Induced Sustained Viral Response.

Abstract: 

Direct-acting antiviral (DAA) therapy for chronic hepatitis C virus (HCV) infection patients (CH) results in a sustained viral response (SVR) in over 95% of patients. However, hepatocellular carcinoma (HCC) occurs in 1-5% of patients who achieved an SVR after treatment with interferon. We attempted to develop a minimally invasive and highly reliable method of predicting the occurrence and recurrence of HCC in patients who achieved an SVR with DAA therapy. The exosomal miRNA expression patterns of 69 CH patients who underwent HCC curative treatment and 70 CH patients were assessed using microarray analysis. We identified a miRNA expression pattern characteristic of SVR-HCC by using machine learning. Twenty-five of 69 patients had HCC recurrence. The expression of four exosomal miRNAs predicted HCC recurrence with 85.3% accuracy. Fifteen of 70 patients had HCC occurrence. The expression of four exosomal miRNAs predicted the onset of HCC with 85.5% accuracy. The expression patterns of miR-4718, 642a-5p, 6826-3p, and 762 in exosomes were positively correlated with those in the liver, and downregulation of these miRNAs induced cell proliferation and prevented apoptosis in vitro. Aberrant expression of four miRNAs, which was used for prediction, was associated with HCC onset after HCV eradication. Expression patterns of exosomal miRNAs are a promising tool to predict SVR-HCC.

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PMID: 

Emerg Microbes Infect. 2019 ;8(1):1626-1635. PMID: 31711408

Abstract Title: 

Dengue haemorrhagic fever: a job done via exosomes?

Abstract: 

Dengue fever is one of those unique diseases where host immune responses largely determine the pathogenesis and its severity. Earlier studies have established the fact that dengue virus (DENV) infection causes haemorrhagic fever and shock syndrome, but it is not directly responsible for exhibiting these clinical symptoms. It is noteworthy that clinically, vascular leakage syndrome does not develop for several days after infection despite a robust innate immune response that elicits the production of proinflammatory and proangiogenic cytokines. The onset of hyperpermeability in severe cases of dengue disease takes place around the time of defervescence and after clearance of viraemia. Extracellular vesicles are known to carry biological information (mRNA, miRNA, transcription factors) from their cells of origin and have emerged as a significant vehicle for horizontal transfer of stress signals. In dengue virus infection, the relevance of exosomes can be instrumental since the majority of the immune responses in severe dengue involve heavy secretion and circulation of pro-inflammatory cytokines and chemokines. Here, we present an updated review which will address the unique and puzzling features of hyperpermeability associated with DENV infection with a special focus on the role of secreted extracellular vesicles.

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PMID: 

Viral Immunol. 2019 Dec ;32(10):453-462. Epub 2019 Nov 22. PMID: 31755827

Abstract Title: 

CD81Exosomes Play a Pivotal Role in the Establishment of Hepatitis C Persistent Infection and Contribute Toward the Progression of Hepatocellular Carcinoma.

Abstract: 

CD81 serves as an immune modulator, playing its role in tumor growth and metastasis of hepatitis C virus (HCV)-mediated hepatocellular carcinoma (HCC). CD81 serves as a coreceptor of viral entry and is found to be enriched in exosomes. HCV E2 protein when associated with CD81 may be responsible for B cell lymphoproliferative disorders, as extrahepatic manifestation. Studies predict that HCV association with exosomes, leads to the establishment of persistent infection, through immune evasion. Herein, we confirm the association of HCV particles with CD81exosomes. Breifly, exosomes were enriched from peripheral blood of chronic HCV patients who have developed HCC. Sideways, exosomes were also enriched from peripheral blood of healthy individuals, who exhibited normal liver function test profile and had no known infection. Isolation of subpopulation of CD81exosomes was performed through immunocapture, followed by detection using FACS. Scanning electron microscopy confirmed the physical association of a fraction of exosome with HCV. CD81exosomes from chronic HCV patients with HCC were more granulated and larger when compared with those enriched from a healthy individual and HCV RNA was also detected in enriched fractions of CD81exosomes from HCV-positive HCC patients only, through real-time quantitative polymerase chain reaction. We concluded that CD81exosomes carry HCV particles and the association plays a pivotal role in establishing persistent infection, through immune evasion, thus leading to HCC progression. Exosomal CD81 and its interacting proteins might, therefore, serve as a potential prognostic marker and therapeutic target in HCV progression mediated by active HCV infection.

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