Exosomes from HIV-1-infected Cells Stimulate Production of Pro-inflammatory Cytokines through Trans-activating Response (TAR) RNA

Neuroinflammation, Blood-Brain Barrier, and HIV Reservoirs in the CNS: An In-Depth Exploration of Latency Mechanisms and Emerging Therapeutic Strategies

Despite the success of antiretroviral therapy (ART) in suppressing viral replication in the blood, HIV persists in the central nervous system (CNS) and causes chronic neurocognitive impairment, a hallmark of HIV-associated neurocognitive disorders (HAND). This review looks at the complex interactions among HIV, the blood-brain barrier (BBB), neuroinflammation, and the roles of viral proteins, immune cell trafficking, and pro-inflammatory mediators in establishing and maintaining latent viral reservoirs in the CNS, particularly microglia and astrocytes. Key findings show disruption of the BBB, monocyte infiltration, and activation of CNS-resident cells by HIV proteins like Tat and gp120, contributing to the neuroinflammatory environment and neuronal damage. Advances in epigenetic regulation of latency have identified targets like histone modifications and DNA methylation, and new therapeutic strategies like latency-reversing agents (LRAs), gene editing (CRISPR/Cas9), and nanoparticle-based drug delivery also offer hope. While we have made significant progress in understanding the molecular basis of HIV persistence in the CNS, overcoming the challenges of BBB penetration and neuroinflammation is key to developing effective therapies. Further research into combination therapies and novel drug delivery systems will help improve outcomes for HAND patients and bring us closer to a functional cure for HIV.

Effect of Kinases in Extracellular Vesicles from HIV-1-Infected Cells on Bystander Cells

As of 2023, there were 39.9 million people living with Human Immunodeficiency Virus type 1 (HIV-1). Although great strides have been made in treatment options for HIV-1, and our understanding of the HIV-1 life cycle has vastly improved since the start of this global health crisis, a functional cure remains elusive. One of the main barriers to a cure is latency, which allows the virus to persist despite combined antiretroviral therapy (cART). Recently, we have found that exosomes, which are small, membrane-enclosed particles released by virtually all cell types and known to mediate intercellular communication, caused an increase in RNA Polymerase II loading onto the HIV-1 promoter. This resulted in the production of both short- and long-length viral transcripts in infected cells under cART. This current study examines the effects of exosome-associated kinases on bystander cells. The phospho-kinase profiling of exosomes revealed differences in the kinase payload of exosomes derived from uninfected and HIV-1-infected cells, with CDK10, GSK3β, and MAPK8 having the largest concentration differences. These kinases were shown to be biologically active and capable of phosphorylating substrates, and they modulated changes in the cell cycle dynamics of exposed cells. Given the relevance of such effects for the immune response, our results implicate exosome-associated kinases as new possible key contributors to HIV-1 pathogenesis that affect bystander cells. These findings may guide new therapeutic avenues to improve the current antiretroviral treatment regimens.

Bridging brain and blood: a prospective view on neuroimaging-exosome correlations in HIV-associated neurocognitive disorders

HIV-associated neurocognitive disorder (HAND) is a complex neurological complication resulting from human immunodeficiency virus (HIV) infection, affecting about 50% of individuals with HIV and significantly diminishing their quality of life. HAND includes a variety of cognitive, motor, and behavioral disorders, severely impacting patients' quality of life and social functioning. Although combination antiretroviral therapy (cART) has greatly improved the prognosis for HIV patients, the incidence of HAND remains high, underscoring the urgent need to better understand its pathological mechanisms and develop early diagnostic methods. This review highlights the latest advancements in neuroimaging and exosome biomarkers in HAND research. Neuroimaging, particularly magnetic resonance imaging (MRI), offers a non-invasive and repeatable method to monitor subtle changes in brain structure and function, potentially detecting early signs of HAND. Meanwhile, exosomes are nano-sized vesicles secreted by cells that serve as key mediators of intercellular communication, playing a crucial role in the neuropathology of HIV and potentially acting as a critical bridge between peripheral blood and central nervous system lesions. Thus, combining plasma exosome biomarkers with indicators derived from neuroimaging scans may enhance the early diagnosis of HAND. This review summarizes evidence supporting the role of exosomes as reliable biomarkers for early detection and management of HAND. Furthermore, we emphasize the correlation between neuroimaging biomarkers and exosome biomarkers and explore their potential combined use. This review discusses the technical challenges and methodological limitations of integrating these two types of biomarkers and proposes future research directions. This multidisciplinary integrative approach not only promises to improve the neurocognitive health management of HIV patients but may also offer valuable insights for research into other neurodegenerative diseases.

Soluble markers of viral rebound and post-treatment HIV control

PURPOSE OF REVIEW

We focus on the different classes of biological molecules measurable in easily accessible bodily fluids that have the potential to serve as biomarkers for the HIV post-treatment controller (PTC) phenotype and/or the timing of viral rebound after stopping antiretroviral therapy (ART).

RECENT FINDINGS

Various viral components and host factors measurable in body fluids can play crucial roles in understanding and predicting the PTC phenotype. We review recent findings linking viral components, the quantitative and qualitative features of antibodies (including autologous HIV-specific antibodies), markers of inflammation and tissue damage, other host proteins (including hormones such as sex hormones), as well as metabolites, extracellular vesicles, and cell-free DNA to HIV control post-ART interruption. Several of these molecules can or have the potential to predict the time and probability of viral rebound after stopping ART and are biologically active molecules that can directly or indirectly (by modulating immune pressures) impact the size and activity of HIV reservoirs during and post-ART interruption.

SUMMARY

A comprehensive model combining multiple markers is needed to predict the PTC phenotype. This model can be leveraged to predict and understand the PTC phenotype, which can guide novel curative interventions to replicate this phenotype in post-treatment non-controllers.

A State-of-the-Art Review on the Recent Advances in Exosomes in Oncogenic Virus

Background and Aims

Oncogenic viruses are responsible for approximately 12% of human malignancies, influencing various cancer processes through intricate interactions with host cells. Exosomes (EXOs), nanometric-sized microvesicles involved in cell communication, have emerged as critical mediators in these interactions. This review aims to explore the mechanisms by which EXOs produced by cells infected with oncogenic viruses promote cancer growth, enhance viral transmissibility, and act as immunomodulators.

Methods

A comprehensive review was conducted, focusing on recent studies highlighting the mechanisms by which EXOs facilitate the oncogenic potential of viruses. The analysis included the characterization of exosomal content, such as microRNAs (miRNAs) and proteins, and their effects on tumor microenvironments and immune responses. A search was performed using databases including PubMed, ScienceDirect, and Google Scholar. MeSH keywords related to EXOs, oncogenic viruses, and cancer were used to retrieve relevant review, systematic, and research articles.

Results

Findings indicate that EXOs from oncogenic virus-infected cells carry viral components that facilitate infection and inflammation. These EXOs alter the tumor microenvironment, contributing to the development of virus-associated cancers. Additionally, the review highlights the growing interest among researchers regarding the implications of EXOs in cancer progression and their potential role in enhancing the oncogenicity of viruses.

Conclusion

The findings underscore the pivotal role of EXOs in mediating the oncogenic effects of viruses, suggesting that targeting exosomal pathways may provide new therapeutic avenues for managing virus-associated cancers. Further research is needed to fully elucidate the functional mechanisms of EXOs in viral oncogenesis.

Dairy: Friend or Foe? Bovine Milk-Derived Extracellular Vesicles and Autoimmune Diseases

Due to the availability, scalability, and low immunogenicity, bovine milk-derived extracellular vesicles (MEVs) are increasingly considered to be a promising carrier of nanomedicines for future therapy. However, considering that extracellular vesicles (EVs) are of biological origin, different sources of EVs, including the host origin and the specific cells that produce the EVs, may have different effects on the structure and function of EVs. Additionally, MEVs play an important role in immune regulation, due to their evolutionary conserved cargo, such as cytokines and miRNAs. Their potential effects on different organs, as well as their accumulation in the human body, should not be overlooked. In this review, we have summarized current impacts and research progress brought about by utilizing MEVs as nano-drug carriers. Nevertheless, we also aim to explore the possible connections between the molecules involved in cellular immunity, cytokines and miRNAs of MEVs produced under different health conditions, and autoimmune diseases.

Extracellular vesicles as carriers for mitochondria: Biological functions and clinical applications

In recent years, research has increasingly focused on the biogenesis of extracellular vesicles (EVs) and the sorting mechanisms for their contents. Mitochondria can be selectively loaded into EVs, serving as a way to maintain cellular mitochondrial homeostasis. EV-mediated mitochondrial transfer has also been shown to greatly impact the function of target cells. Based on the mechanism of EV-mediated mitochondrial transfer, therapies can be developed to treat human diseases. This review summarizes the recent advances in the biogenesis and molecular composition of EVs. It also highlights the sorting and trafficking mechanisms of mitochondrial components into EVs. Furthermore, it explores the current role of EV-mediated mitochondrial transfer in the development of human diseases, as well as its diagnostic and therapeutic applications.

Extracellular vesicle isolation methods identify distinct HIV-1 particles released from chronically infected T-cells

The current study analyzed the intersecting biophysical, biochemical, and functional properties of extracellular particles (EPs) with the human immunodeficiency virus type-1 (HIV-1) beyond the currently accepted size range for HIV-1. We isolated five fractions (Frac-A through Frac-E) from HIV-infected cells by sequential differential ultracentrifugation (DUC). All fractions showed a heterogeneous size distribution with median particle sizes greater than 100 nm for Frac-A through Frac-D but not for Frac-E, which contained small EPs with an average size well below 50 nm. Synchronized and released cultures contained large infectious EPs in Frac-A, with markers of amphisomes and viral components. Additionally, Frac-E uniquely contained EPs positive for CD63, HSP70, and HIV-1 proteins. Despite its small average size, Frac-E contained membrane-protected viral integrase, detectable only after SDS treatment, indicating that it is enclosed in vesicles. Single particle analysis with dSTORM further supported these findings as CD63, HIV-1 integrase, and the viral surface envelope (Env) glycoprotein (gp) colocalized on the same Frac-E particles. Surprisingly, Frac-E EPs were infectious, and infectivity was significantly reduced by immunodepleting Frac-E with anti-CD63, indicating the presence of this protein on the surface of infectious small EPs in Frac-E. To our knowledge, this is the first time that extracellular vesicle (EV) isolation methods have identified infectious small HIV-1 particles (smHIV-1) that are under 50 nm. Collectively, our data indicate that the crossroads between EPs and HIV-1 potentially extend beyond the currently accepted biophysical properties of HIV-1, which may have further implications for viral pathogenesis.

The Role of Extracellular Vesicles in Pandemic Viral Infections

Extracellular vesicles (EVs), of diverse origin and content, are membranous structures secreted by a broad range of cell types. Recent advances in molecular biology have highlighted the pivotal role of EVs in mediating intercellular communication, facilitated by their ability to transport a diverse range of biomolecules, including proteins, lipids, DNA, RNA and metabolites. A striking feature of EVs is their ability to exert dual effects during viral infections, involving both proviral and antiviral effects. This review explores the dual roles of EVs, particularly in the context of pandemic viruses such as HIV-1 and SARS-CoV-2. On the one hand, EVs can enhance viral replication and exacerbate pathogenesis by transferring viral components to susceptible cells. On the other hand, they have intrinsic antiviral properties, including activation of immune responses and direct inhibition of viral infection. By exploring these contrasting functions, our review emphasizes the complexity of EV-mediated interactions in viral pathogenesis and highlights their potential as targets for therapeutic intervention. The insights obtained from investigating EVs in the context of HIV-1 and SARS-CoV-2 provide a deeper understanding of viral mechanisms and pathologies, and offer a new perspective on managing and mitigating the impact of these global health challenges.

HIV-1 RNA in extracellular vesicles is associated with neurocognitive outcomes

Human immunodeficiency virus type-1 (HIV-1) is responsible for significant mortality and morbidity worldwide. Despite complete control of viral replication with antiretrovirals, cells with integrated HIV-1 provirus can produce viral transcripts. In a cross-sectional study of 84 HIV+ individuals of whom 43 were followed longitudinally, we found that HIV-1 RNAs are present in extracellular vesicles (EVs) derived from cerebrospinal fluid and serum of all individuals. We used seven digital droplet polymerase chain reaction assays to evaluate the transcriptional status of the latent reservoir. EV-associated viral RNA was more abundant in the CSF and correlated with neurocognitive dysfunction in both, the cross-sectional and longitudinal studies. Sequencing studies suggested compartmentalization of defective viral transcripts in the serum and CSF. These findings suggest previous studies have underestimated the viral burden and there is a significant relationship between latent viral transcription and CNS complications of long-term disease despite the adequate use of antiretrovirals.

Multiple treatment interruptions and protecting HIV-specific CD4 T cells enable durable CD8 T cell response and viral control

Human Immunodeficiency Virus (HIV) remains a global health challenge, and novel approaches to improve HIV control are significantly important. The cell and gene therapy product AGT103-T was previously evaluated (NCT04561258) for safety, immunogenicity, and persistence in seven patients for up to 180 days post infusion. In this study, we sought to investigate the impact of AGT103-T treatment upon analytical treatment interruptions (ATIs). Six patients previously infused with AGT103-T were enrolled into an ATI study (NCT05540964), wherein they suspended their antiretroviral therapy (ART) until their viral load reached 100,000 copies/mL in two successive visits, or their CD4 count was reduced to below 300 cells/μL. During the ATI, all patients experienced viral rebound followed by a notable expansion in HIV specific immune responses. The participants demonstrated up to a five-fold increase in total CD8 counts over baseline approximately 1-2 weeks followed by the peak viremia. This coincided with a rise in HIV-specific CD8 T cells, which was attributed to the increase in antigen availability and memory recall. Thus, the protocol was amended to include a second ATI with the first ATI serving as an "auto-vaccination." Four patients participated in a second ATI. During the second ATI, the Gag-specific CD8 T cells were either maintained or rose in response to viral rebound and the peak viremia was substantially decreased. The patients reached a viral set point ranging from 7,000 copies/mL to 25,000 copies/mL. Upon resuming ART, all participants achieved viral control more rapidly than during the first ATI, with CD4 counts remaining within 10% of baseline measurements and without any serious adverse events or evidence of drug resistance. In summary, the rise in CD8 counts and the viral suppression observed in 100% of the study participants are novel observations demonstrating that AGT103-T gene therapy when combined with multiple ATIs, is a safe and effective approach for achieving viral control, with viral setpoints consistently below 25,000 copies/mL and relatively stable CD4 T cell counts. We conclude that HIV cure-oriented cell and gene therapy trials should include ATI and may benefit from designs that include multiple ATIs when induction of CD8 T cells is required to establish viral control.

Regulation of immune responses to infection through interaction between stem cell-derived exosomes and toll-like receptors mediated by microRNA cargoes

Infectious diseases are among the factors that account for a significant proportion of disease-related deaths worldwide. The primary treatment approach to combat microbial infections is the use of antibiotics. However, the widespread use of these drugs over the past two decades has led to the emergence of resistant microbial species, making the control of microbial infections a serious challenge. One of the most important solutions in the field of combating infectious diseases is the regulation of the host's defense system. Toll-like receptors (TLRs) play a crucial role in the first primary defense against pathogens by identifying harmful endogenous molecules released from dying cells and damaged tissues as well as invading microbial agents. Therefore, they play an important role in communicating and regulating innate and adaptive immunity. Of course, excessive activation of TLRs can lead to disruption of immune homeostasis and increase the risk of inflammatory reactions. Targeting TLR signaling pathways has emerged as a new therapeutic approach for infectious diseases based on host-directed therapy (HDT). In recent years, stem cell-derived exosomes have received significant attention as factors regulating the immune system. The regulation effects of exosomes on the immune system are based on the HDT strategy, which is due to their cargoes. In general, the mechanism of action of stem cell-derived exosomes in HDT is by regulating and modulating immunity, promoting tissue regeneration, and reducing host toxicity. One of their most important cargoes is microRNAs, which have been shown to play a significant role in regulating immunity through TLRs. This review investigates the therapeutic properties of stem cell-derived exosomes in combating infections through the interaction between exosomal microRNAs and Toll-like receptors.

Unravelling the triad of neuroinvasion, neurodissemination, and neuroinflammation of human immunodeficiency virus type 1 in the central nervous system

Since the identification of human immunodeficiency virus type 1 (HIV-1) in 1983, many improvements have been made to control viral replication in the peripheral blood and to treat opportunistic infections. This has increased life expectancy but also the incidence of age-related central nervous system (CNS) disorders and HIV-associated neurodegeneration/neurocognitive impairment and depression collectively referred to as HIV-associated neurocognitive disorders (HAND). HAND encompasses a spectrum of different clinical presentations ranging from milder forms such as asymptomatic neurocognitive impairment or mild neurocognitive disorder to a severe HIV-associated dementia (HAD). Although control of viral replication and suppression of plasma viral load with combination antiretroviral therapy has reduced the incidence of HAD, it has not reversed milder forms of HAND. The objective of this review, is to describe the mechanisms by which HIV-1 invades and disseminates in the CNS, a crucial event leading to HAND. The review will present the evidence that underlies the relationship between HIV infection and HAND. Additionally, recent findings explaining the role of neuroinflammation in the pathogenesis of HAND will be discussed, along with prospects for treatment and control.

Autophagy Deregulation in HIV-1-Infected Cells Increases Extracellular Vesicle Release and Contributes to TLR3 Activation

Human immunodeficiency virus type 1 (HIV-1) infection can result in HIV-associated neurocognitive disorder (HAND), a spectrum of disorders characterized by neurological impairment and chronic inflammation. Combined antiretroviral therapy (cART) has elicited a marked reduction in the number of individuals diagnosed with HAND. However, there is continual, low-level viral transcription due to the lack of a transcription inhibitor in cART regimens, which results in the accumulation of viral products within infected cells. To alleviate stress, infected cells can release accumulated products, such as TAR RNA, in extracellular vesicles (EVs), which can contribute to pathogenesis in neighboring cells. Here, we demonstrate that cART can contribute to autophagy deregulation in infected cells and increased EV release. The impact of EVs released from HIV-1 infected myeloid cells was found to contribute to CNS pathogenesis, potentially through EV-mediated TLR3 (Toll-like receptor 3) activation, suggesting the need for therapeutics to target this mechanism. Three HIV-1 TAR-binding compounds, 103FA, 111FA, and Ral HCl, were identified that recognize TAR RNA and reduce TLR activation. These data indicate that packaging of viral products into EVs, potentially exacerbated by antiretroviral therapeutics, may induce chronic inflammation of the CNS observed in cART-treated patients, and novel therapeutic strategies may be exploited to mitigate morbidity.

The extracellular vesicles in HIV infection and progression: mechanisms, and theranostic implications

Extracellular vesicles (EVs), these minute yet mighty cellular messengers are redefining our understanding of a spectrum of diseases, from cancer to cardiovascular ailments, neurodegenerative disorders, and even infectious diseases like HIV. Central to cellular communication, EVs emerge as both potent facilitators and insightful biomarkers in immune response and the trajectory of disease progression. This review ventures deep into the realm of EVs in HIV-unraveling their pivotal roles in diagnosis, disease mechanism unravelling, and therapeutic innovation. With a focus on HIV, we will highlights the transformative potential of EVs in both diagnosing and treating this formidable virus. Unveiling the intricate dance between EVs and HIV, the review aims to shed light on novel therapeutic strategies that could significantly benefit HIV therapy, potentially even leading to the eradication of HIV.

Dissemination of the Flavivirus Subgenomic Replicon Genome and Viral Proteins by Extracellular Vesicles

Extracellular vesicles (EVs) such as exosomes have been shown to play physiological roles in cell-to-cell communication by delivering various proteins and nucleic acids. In addition, several studies revealed that the EVs derived from the cells that are infected with certain viruses could transfer the full-length viral genomes, resulting in EVs-mediated virus propagation. However, the possibility cannot be excluded that the prepared EVs were contaminated with infectious viral particles. In this study, the cells that harbor subgenomic replicon derived from the Japanese encephalitis virus and dengue virus without producing any replication-competent viruses were employed as the EV donor. It was demonstrated that the EVs in the culture supernatants of those cells were able to transfer the replicon genome to other cells of various types. It was also shown that the EVs were incorporated by the recipient cells primarily through macropinocytosis after interaction with CD33 and Tim-1/Tim-4 on HeLa and K562 cells, respectively. Since the methods used in this study are free from contamination with infectious viral particles, it is unequivocally indicated that the flavivirus genome can be transferred by EVs from cell to cell, suggesting that this pathway, in addition to the classical receptor-mediated infection, may play some roles in the viral propagation and pathogenesis.

Role of HIV-1 Tat Protein Interactions with Host Receptors in HIV Infection and Pathogenesis

Each time the virus starts a new round of expression/replication, even under effective antiretroviral therapy (ART), the transactivator of viral transcription Tat is one of the first HIV-1 protein to be produced, as it is strictly required for HIV replication and spreading. At this stage, most of the Tat protein exits infected cells, accumulates in the extracellular matrix and exerts profound effects on both the virus and neighbor cells, mostly of the innate and adaptive immune systems. Through these effects, extracellular Tat contributes to the acquisition of infection, spreading and progression to AIDS in untreated patients, or to non-AIDS co-morbidities in ART-treated individuals, who experience inflammation and immune activation despite virus suppression. Here, we review the role of extracellular Tat in both the virus life cycle and on cells of the innate and adaptive immune system, and we provide epidemiological and experimental evidence of the importance of targeting Tat to block residual HIV expression and replication. Finally, we briefly review vaccine studies showing that a therapeutic Tat vaccine intensifies ART, while its inclusion in a preventative vaccine may blunt escape from neutralizing antibodies and block early events in HIV acquisition.

Progress in cancer neuroscience

Cancer of the central nervous system (CNS) can crosstalk systemically and locally in the tumor microenvironment and has become a topic of attention for tumor initiation and advancement. Recently studied neuronal and cancer interaction fundamentally altered the knowledge about glioma and metastases, indicating how cancers invade complex neuronal networks. This review systematically discussed the interactions between neurons and cancers and elucidates new therapeutic avenues. We have overviewed the current understanding of direct or indirect communications of neuronal cells with cancer and the mechanisms associated with cancer invasion. Besides, tumor-associated neuronal dysfunction and the influence of cancer therapies on the CNS are highlighted. Furthermore, interactions between peripheral nervous system and various cancers have also been discussed separately. Intriguingly and importantly, it cannot be ignored that exosomes could mediate the "wireless communications" between nervous system and cancer. Finally, promising future strategies targeting neuronal-brain tumor interactions were reviewed. A great deal of work remains to be done to elucidate the neuroscience of cancer, and future more research should be directed toward clarifying the precise mechanisms of cancer neuroscience, which hold enormous promise to improve outcomes for a wide range of malignancies.

Mechanisms underlying HIV-associated cognitive impairment and emerging therapies for its management

People living with HIV are affected by the chronic consequences of neurocognitive impairment (NCI) despite antiretroviral therapies that suppress viral replication, improve health and extend life. Furthermore, viral suppression does not eliminate the virus, and remaining infected cells may continue to produce viral proteins that trigger neurodegeneration. Comorbidities such as diabetes mellitus are likely to contribute substantially to CNS injury in people living with HIV, and some components of antiretroviral therapy exert undesirable side effects on the nervous system. No treatment for HIV-associated NCI has been approved by the European Medicines Agency or the US Food and Drug Administration. Historically, roadblocks to developing effective treatments have included a limited understanding of the pathophysiology of HIV-associated NCI and heterogeneity in its clinical manifestations. This heterogeneity might reflect multiple underlying causes that differ among individuals, rather than a single unifying neuropathogenesis. Despite these complexities, accelerating discoveries in HIV neuropathogenesis are yielding potentially druggable targets, including excessive immune activation, metabolic alterations culminating in mitochondrial dysfunction, dysregulation of metal ion homeostasis and lysosomal function, and microbiome alterations. In addition to drug treatments, we also highlight the importance of non-pharmacological interventions. By revisiting mechanisms implicated in NCI and potential interventions addressing these mechanisms, we hope to supply reasons for optimism in people living with HIV affected by NCI and their care providers.

Exosomes multifunctional roles in HIV-1: insight into the immune regulation, vaccine development and current progress in delivery system

Human Immunodeficiency Virus (HIV-1) is known to establish a persistent latent infection. The use of combination antiretroviral therapy (cART) can effectively reduce the viral load, but the treatment can be costly and may lead to the development of drug resistance and life-shortening side effects. It is important to develop an ideal and safer in vivo target therapy that will effectively block viral replication and expression in the body. Exosomes have recently emerged as a promising drug delivery vehicle due to their low immunogenicity, nanoscale size (30-150nm), high biocompatibility, and stability in the targeted area. Exosomes, which are genetically produced by different types of cells such as dendritic cells, neurons, T and B cells, epithelial cells, tumor cells, and mast cells, are designed for efficient delivery to targeted cells. In this article, we review and highlight recent developments in the strategy and application of exosome-based HIV-1 vaccines. We also discuss the use of exosome-based antigen delivery systems in vaccine development. HIV-1 antigen can be loaded into exosomes, and this modified cargo can be delivered to target cells or tissues through different loading approaches. This review also discusses the immunological prospects of exosomes and their role as biomarkers in disease progression. However, there are significant administrative and technological obstacles that need to be overcome to fully harness the potential of exosome drug delivery systems.

Extracellular vesicles as biomarkers for AIDS-associated non-Hodgkin lymphoma risk

Introduction

Extracellular vesicles are membrane-bound structures secreted into the extracellular milieu by cells and can carry bioactive molecules. There is emerging evidence suggesting that EVs play a role in the diagnosis, treatment, and prognosis of certain cancers. In this study, we investigate the association of EVs bearing PD-L1 and molecules important in B-cell activation and differentiation with AIDS-NHL risk.

Methods

EVs were isolated from archived serum collected prior to the diagnosis of AIDS-NHL in cases (N = 51) and matched HIV+ controls (N = 52) who were men enrolled in the Los Angeles site of the MACS/WIHS Combined Cohort Study (MWCCS). Serum specimens of AIDS-NHL cases were collected at a mean time of 1.25 years (range of 2 to 36 months) prior to an AIDS-NHL diagnosis. The expression of PD-L1 and other molecules on EVs (CD40, CD40L, TNF-RII, IL-6Rα, B7-H3, ICAM-1, and FasL) were quantified by Luminex multiplex assay.

Results and discussion

We observed significantly higher levels of EVs bearing PD-L1, CD40, TNF-RII and/or IL-6Rα in AIDS-NHL cases compared with controls. Using multivariate conditional logistic regression models adjusted for age and CD4+ T-cell count, we found that EVs bearing PD-L1 (OR = 1.93; 95% CI: 1.10 - 3.38), CD40 (OR = 1.97, 95% CI: 1.09 - 3.58), TNF-RII (OR = 5.06; 95% CI: 1.99 - 12.85) and/or IL-6Rα (OR = 4.67; 95% CI: 1.40 - 15.53) were significantly and positively associated with AIDS-NHL risk. In addition, EVs bearing these molecules were significantly and positively associated with non-CNS lymphoma: PD-L1 (OR = 1.94; 95% CI: 1.01 - 3.72); CD40 (OR = 2.66; 95% CI: 1.12 - 6.35); TNF-RII (OR = 9.64; 95% CI: 2.52 - 36.86); IL-6Rα (OR = 8.34; 95% CI: 1.73 - 40.15). These findings suggest that EVs bearing PD-L1, CD40, TNF-RII and/or IL-6Rα could serve as biomarkers for the early detection of NHL in PLWH.

Extracellular Vesicles as a Translational Approach for the Treatment of COVID-19 Disease: An Updated Overview

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a global pandemic in the years 2020-2022. With a high prevalence, an easy route of transmission, and a long incubation time, SARS-CoV-2 spread quickly and affected public health and socioeconomic conditions. Several points need to be elucidated about its mechanisms of infection, in particular, its capability to evade the immune system and escape from neutralizing antibodies. Extracellular vesicles (EVs) are phospholipid bilayer-delimited particles that are involved in cell-to-cell communication; they contain biological information such as miRNAs, proteins, nucleic acids, and viral components. Abundantly released from biological fluids, their dimensions are highly variable, which are used to divide them into exosomes (40 to 150 nm), microvesicles (40 to 10,000 nm), and apoptotic bodies (100-5000 nm). EVs are involved in many physiological and pathological processes. In this article, we report the latest evidence about EVs' roles in viral infections, focusing on the dual role of exosomes in promoting and inhibiting SARS-CoV-2 infection. The involvement of mesenchymal stromal/stem cells (MSCs) and MSC-derived EVs in COVID-19 treatment, such as the use of translational exosomes as a diagnostical/therapeutic approach, is also investigated. These elucidations could be useful to better direct the discovery of future diagnostical tools and new exosome-derived COVID-19 biomarkers, which can help achieve optimal therapeutic interventions and implement future vaccine strategies.

Viral Immune signatures from cerebrospinal fluid extracellular vesicles and particles in HAM and other chronic neurological diseases

Background and objectives

Extracellular vesicles and particles (EVPs) are released from virtually all cell types, and may package many inflammatory factors and, in the case of infection, viral components. As such, EVPs can play not only a direct role in the development and progression of disease but can also be used as biomarkers. Here, we characterized immune signatures of EVPs from the cerebrospinal fluid (CSF) of individuals with HTLV-1-associated myelopathy (HAM), other chronic neurologic diseases, and healthy volunteers (HVs) to determine potential indicators of viral involvement and mechanisms of disease.

Methods

We analyzed the EVPs from the CSF of HVs, individuals with HAM, HTLV-1-infected asymptomatic carriers (ACs), and from patients with a variety of chronic neurologic diseases of both known viral and non-viral etiologies to investigate the surface repertoires of CSF EVPs during disease.

Results

Significant increases in CD8+ and CD2+ EVPs were found in HAM patient CSF samples compared to other clinical groups (p = 0.0002 and p = 0.0003 compared to HVs, respectively, and p = 0.001 and p = 0.0228 compared to MS, respectively), consistent with the immunopathologically-mediated disease associated with CD8+ T-cells in the central nervous system (CNS) of HAM patients. Furthermore, CD8+ (p < 0.0001), CD2+ (p < 0.0001), CD44+ (p = 0.0176), and CD40+ (p = 0.0413) EVP signals were significantly increased in the CSF from individuals with viral infections compared to those without.

Discussion

These data suggest that CD8+ and CD2+ CSF EVPs may be important as: 1) potential biomarkers and indicators of disease pathways for viral-mediated neurological diseases, particularly HAM, and 2) as possible meditators of the disease process in infected individuals.

The complex role of extracellular vesicles in HIV infection

During normal physiological and abnormal pathophysiological conditions, all cells release membrane vesicles, termed extracellular vesicles (EVs). Growing evidence has revealed that EVs act as important messengers in intercellular communication. EVs play emerging roles in cellular responses and the modulation of immune responses during virus infection. EVs contribute to triggering antiviral responses to restrict virus infection and replication. Conversely, the role of EVs in the facilitation of virus spread and pathogenesis has been widely documented. Depending on the cell of origin, EVs carry effector functions from one cell to the other by horizontal transfer of their bioactive cargoes, including DNA, RNA, proteins, lipids, and metabolites. The diverse constituents of EVs can reflect the altered states of cells or tissues during virus infection, thereby offering a diagnostic readout. The exchanges of cellular and/or viral components by EVs can inform the therapeutic potential of EVs for infectious diseases. This review discusses recent advances of EVs to explore the complex roles of EVs during virus infection and their therapeutic potential, focusing on HIV-1. [BMB Reports 2023; 56(6): 335-340].

The complex role of extracellular vesicles in HIV infection

During normal physiological and abnormal pathophysiological conditions, all cells release membrane vesicles, termed extracellular vesicles (EVs). Growing evidence has revealed that EVs act as important messengers in intercellular communication. EVs play emerging roles in cellular responses and the modulation of immune responses during virus infection. EVs contribute to triggering antiviral responses to restrict virus infection and replication. Conversely, the role of EVs in the facilitation of virus spread and pathogenesis has been widely documented. Depending on the cell of origin, EVs carry effector functions from one cell to the other by horizontal transfer of their bioactive cargoes, including DNA, RNA, proteins, lipids, and metabolites. The diverse constituents of EVs can reflect the altered states of cells or tissues during virus infection, thereby offering a diagnostic readout. The exchanges of cellular and/or viral components by EVs can inform the therapeutic potential of EVs for infectious diseases. This review discusses recent advances of EVs to explore the complex roles of EVs during virus infection and their therapeutic potential, focusing on HIV-1. [BMB Reports 2023; 56(6): 335-340].

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.

Circulating Plasma Exosomal Proteins of Either SHIV-Infected Rhesus Macaque or HIV-Infected Patient Indicates a Link to Neuropathogenesis

Despite the suppression of human immunodeficiency virus (HIV) replication by combined antiretroviral therapy (cART), 50-60% of HIV-infected patients suffer from HIV-associated neurocognitive disorders (HAND). Studies are uncovering the role of extracellular vesicles (EVs), especially exosomes, in the central nervous system (CNS) due to HIV infection. We investigated links among circulating plasma exosomal (crExo) proteins and neuropathogenesis in simian/human immunodeficiency virus (SHIV)-infected rhesus macaques (RM) and HIV-infected and cART treated patients (Patient-Exo). Isolated EVs from SHIV-infected (SHIV-Exo) and uninfected (CTL-Exo) RM were predominantly exosomes (particle size < 150 nm). Proteomic analysis quantified 5654 proteins, of which 236 proteins (~4%) were significantly, differentially expressed (DE) between SHIV-/CTL-Exo. Interestingly, different CNS cell specific markers were abundantly expressed in crExo. Proteins involved in latent viral reactivation, neuroinflammation, neuropathology-associated interactive as well as signaling molecules were expressed at significantly higher levels in SHIV-Exo than CTL-Exo. However, proteins involved in mitochondrial biogenesis, ATP production, autophagy, endocytosis, exocytosis, and cytoskeleton organization were significantly less expressed in SHIV-Exo than CTL-Exo. Interestingly, proteins involved in oxidative stress, mitochondrial biogenesis, ATP production, and autophagy were significantly downregulated in primary human brain microvascular endothelial cells exposed with HIV+/cART+ Patient-Exo. We showed that Patient-Exo significantly increased blood-brain barrier permeability, possibly due to loss of platelet endothelial cell adhesion molecule-1 protein and actin cytoskeleton structure. Our novel findings suggest that circulating exosomal proteins expressed CNS cell markers-possibly associated with viral reactivation and neuropathogenesis-that may elucidate the etiology of HAND.

The interplay among HIV, monocytes/macrophages, and extracellular vesicles: a systematic review

Despite effective antiretroviral therapies, chronic inflammation and spontaneous viral "blips" occur in HIV-infected patients. Given the roles for monocytes/macrophages in HIV pathogenesis and extracellular vesicles in intercellular communication, we performed this systematic review to delineate the triad of HIV, monocytes/macrophages, and extracellular vesicles in the modulation of immune activation and HIV activities. We searched PubMed, Web of Science, and EBSCO databases for published articles, up to 18 August 2022, relevant to this triad. The search identified 11,836 publications, and 36 studies were deemed eligible and included in this systematic review. Data were extracted for the characteristics of HIV, monocytes/macrophages, and extracellular vesicles used for experiments and the immunologic and virologic outcomes in extracellular vesicle recipient cells. Evidence for the effects on outcomes was synthesized by stratifying the characteristics by outcomes. In this triad, monocytes/macrophages were potential producers and recipients of extracellular vesicles, whose cargo repertoires and functionalities were regulated by HIV infection and cellular stimulation. Extracellular vesicles derived from HIV-infected monocytes/macrophages or the biofluid of HIV-infected patients enhanced innate immune activation and HIV dissemination, cellular entry, replication, and latency reactivation in bystander or infected target cells. These extracellular vesicles could be synthesized in the presence of antiretroviral agents and elicit pathogenic effects in a wide range of nontarget cells. At least eight functional types of extracellular vesicles could be classified based on the diverse extracellular vesicle effects, which were linked to specific virus- and/or host-derived cargos. Thus, the monocyte/macrophage-centered multidirectional crosstalk through extracellular vesicles may help sustain persistent immune activation and residual viral activities during suppressed HIV infection.

Extracellular Vesicles and Viruses: Two Intertwined Entities

Viruses share many attributes in common with extracellular vesicles (EVs). The cellular machinery that is used for EV production, packaging of substrates and secretion is also commonly manipulated by viruses for replication, assembly and egress. Viruses can increase EV production or manipulate EVs to spread their own genetic material or proteins, while EVs can play a key role in regulating viral infections by transporting immunomodulatory molecules and viral antigens to initiate antiviral immune responses. Ultimately, the interactions between EVs and viruses are highly interconnected, which has led to interesting discoveries in their associated roles in the progression of different diseases, as well as the new promise of combinational therapeutics. In this review, we summarize the relationships between viruses and EVs and discuss major developments from the past five years in the engineering of virus-EV therapies.

Role of Autophagy in HIV-1 and Drug Abuse-Mediated Neuroinflammaging

Chronic low-grade inflammation remains an essential feature of HIV-1 infection under combined antiretroviral therapy (cART) and contributes to the accelerated cognitive defects and aging in HIV-1 infected populations, indicating cART limitations in suppressing viremia. Interestingly, ~50% of the HIV-1 infected population on cART that develops cognitive defects is complicated by drug abuse, involving the activation of cells in the central nervous system (CNS) and neurotoxin release, altogether leading to neuroinflammation. Neuroinflammation is the hallmark feature of many neurodegenerative disorders, including HIV-1-associated neurocognitive disorders (HAND). Impaired autophagy has been identified as one of the underlying mechanisms of HAND in treated HIV-1-infected people that also abuse drugs. Several lines of evidence suggest that autophagy regulates CNS cells' responses and maintains cellular hemostasis. The impairment of autophagy is associated with low-grade chronic inflammation and immune senescence, a known characteristic of pathological aging. Therefore, autophagy impairment due to CNS cells, such as neurons, microglia, astrocytes, and pericytes exposure to HIV-1/HIV-1 proteins, cART, and drug abuse could have combined toxicity, resulting in increased neuroinflammation, which ultimately leads to accelerated aging, referred to as neuroinflammaging. In this review, we focus on the potential role of autophagy in the mechanism of neuroinflammaging in the context of HIV-1 and drug abuse.

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.

Exosomes─Nature's Lipid Nanoparticles, a Rising Star in Drug Delivery and Diagnostics

Exosomes are a subgroup of nanosized extracellular vesicles enclosed by a lipid bilayer membrane and secreted by most eukaryotic cells. They represent a route of intercellular communication and participate in a wide variety of physiological and pathological processes. The biological roles of exosomes rely on their bioactive cargos, including proteins, nucleic acids, and lipids, which are delivered to target cells. Their distinctive properties─innate stability, low immunogenicity, biocompatibility, and good biomembrane penetration capacity─allow them to function as superior natural nanocarriers for efficient drug delivery. Another notably favorable clinical application of exosomes is in diagnostics. They hold various biomolecules from host cells, which are indicative of pathophysiological conditions; therefore, they are considered vital for biomarker discovery in clinical diagnostics. Here, we use data from the CAS Content Collection and provide a landscape overview of the current state and delineate trends in research advancement on exosome applications in therapeutics and diagnostics across time, geography, composition, cargo loading, and development pipelines. We discuss exosome composition and pathway, from their biogenesis and secretion from host cells to recipient cell uptake. We assess methods for exosome isolation and purification, their clinical applications in therapy and diagnostics, their development pipelines, the exploration goals of the companies, the assortment of diseases they aim to treat, development stages of their research, and publication trends. We hope this review will be useful for understanding the current knowledge in the field of medical applications of exosomes, in an effort to further solve the remaining challenges in fulfilling their potential.

Emerging roles of hnRNP A2B1 in cancer and inflammation

Heterogeneous nuclear ribonucleoproteins (hnRNPs) are a group of RNA-binding proteins with important roles in multiple aspects of nucleic acid metabolism, including the packaging of nascent transcripts, alternative splicing, transactivation of gene expression, and regulation of protein translation. As a core component of the hnRNP complex in mammalian cells, heterogeneous nuclear ribonucleoprotein A2B1 (hnRNP A2B1) participates in and coordinates various molecular events. Given its regulatory role in inflammation and cancer progression, hnRNP A2B1 has become a novel player in immune response, inflammation, and cancer development. Concomitant with these new roles, a surprising number of mechanisms deemed to regulate hnRNP A2B1 functions have been identified, including post-translational modifications, changes in subcellular localization, direct interactions with multiple DNAs, RNAs, and proteins or the formation of complexes with them, which have gradually made hnRNP A2B1 a molecular target for multiple drugs. In light of the rising interest in the intersection between cancer and inflammation, this review will focus on recent knowledge of the biological roles of hnRNP A2B1 in cancer, immune response, and inflammation.

CMV and EBV Co-Infection in HIV-Infected Children: Infection Rates and Analysis of Differential Expression of Cytokines in HIV Mono- and HIV-CMV-EBV Co-Infected Groups

(1) Background: CMV and EBV co-infections can affect the HIV disease progression by modulating the immune system. The disease dynamics can differ in HIV-positive adults and children. In Pakistan, HIV is rapidly expanding, especially in children; however, the prevalence of CMV and EBV co-infection and the effect on immune modulation in HIV-positive children are not known. This study aimed to bridge this gap by estimating the rate of active CMV and EBV co-infection in HIV-positive children, followed by the analysis of differential expression of cytokines in HIV mono- and HIV/CMV/EBV co-infected children. (2) Methods: DNA samples from 319 HIV-positive children, previously recruited as part of a study to investigate the HIV outbreak in Larkana, Pakistan, in 2019, were screened for CMV and EBV through qPCR. Subsequently, differences in HIV viral loads and CD4 counts were analyzed between the HIV mono- and HIV/CMV/EBV co-infected groups. The RNA samples were used to determine the differential expression of both pro- and anti-inflammatory cytokines in the mono- and co-infected groups using RT-qPCR, while unpaired T-test and Pearson correlation test were applied to, respectively, analyze the differential cytokine expression and correlation between cytokine in the two groups. (3) Results: Of 319 samples, the rate of active EBV and CMV co-infection in HIV-positive children was observed in 79.9% and 38.9%, respectively. A significant difference was observed in HIV viral load between HIV mono- and co-infected groups. IFN-γ expression was found to be lower in the HIV mono-infected group, while higher in all other three co-infected groups. Meanwhile, mRNA expression of TGF-β1 was found to be lower in HIV mono- and HIV-CMV-EBV co-infected groups, while higher in HIV-CMV and HIV-EBV co-infected groups. IFN-γ and IL-2 exhibited a significant positive correlation in all except HIV-CMV co-infected group. (4) Conclusions: The study suggests that the presence of EBV/CMV co-infection can affect the HIV viral loads and expression of certain cytokines (IFN-γ and TGF-β1), which may affect the HIV disease dynamics in infected children.

The Role of Extracellular Vesicles in COVID-19 Pathology

Extracellular vesicles (EVs) have become a trending topic in recent years; they constitute a new intercellular communication paradigm. Extracellular vesicles are 30–4000 nanometers in diameter particles that are limited by a phospholipid bilayer and contain functional biomolecules, such as proteins, lipids, and nucleic acids. They are released by virtually all types of eukaryotic cells; through their cargoes, EVs are capable of triggering signaling in recipient cells. In addition to their functions in the homeostatic state, EVs have gained attention because of their roles in pathological contexts, eventually contributing to disease progression. In the Coronavirus disease 2019 (COVID-19) pandemic, aside from the scientific race for the development of preventive and therapeutic interventions, it is critical to understand the pathological mechanisms involved in SARS-CoV-2 infection. In this sense, EVs are key players in the main processes of COVID-19. Thus, in this review, we highlight the role of EVs in the establishment of the viral infection and in the procoagulant state, cytokine storm, and immunoregulation of innate and adaptive immune responses.

Crosstalk between R848 and abortive HIV-1 RNA-induced signaling enhances antiviral immunity

Pathogens trigger multiple pattern recognition receptors (PRRs) that together dictate innate and adaptive immune responses. Understanding the crosstalk between PRRs is important to enhance vaccine efficacy. Abortive HIV-1 RNA transcripts are produced during acute and chronic HIV-1 infection and are known ligands for different PRRs, leading to antiviral and proinflammatory responses. Here, we have investigated the crosstalk between responses induced by these 58 nucleotide-long HIV-1 RNA transcripts and different TLR ligands. Costimulation of dendritic cells (DCs) with abortive HIV-1 RNA and TLR7/8 agonist R848, but not other TLR agonists, resulted in enhanced antiviral type I IFN responses as well as adaptive immune responses via the induction of DC-mediated T helper 1 (TH 1) responses and IFNγ+ CD8+ T cells. Our data underscore the importance of crosstalk between abortive HIV-1 RNA and R848-induced signaling for the induction of effective antiviral immunity.

Effects of Exosomal Viral Components on the Tumor Microenvironment

Simple Summary

Oncogenic viral infection may lead to cancers, such as nasopharyngeal carcinoma, hepatocellular carcinoma, and cervical cancer. In addition to the tumor cells themselves, the tumor microenvironment also plays a decisive role in tumor evolution. Oncogenic viruses can affect the tumor microenvironment via exosomes influencing the occurrence and development of tumors by encapsulating and transporting viral components. This review focuses on the effects of virus-infected cancer exosomes on tumor microenvironment and tumor progression.

Abstract

Exosomes are extracellular membrane vesicles with a diameter of 30–100 nm, produced by different eukaryotic cells that contain multitudinous lipids, nucleic acids, and proteins. They transfer membrane components and nucleic acids between cells, thereby performing an information exchange between cells. Many studies have shown that a variety of tumor-associated viruses can exert their biological functions through exosomes. The tumor microenvironment (TME) is very important in the occurrence, development, and chemoresistance of tumors. It is composed of tumor cells, fibroblasts, endothelial cells, immune cells, stromal cells, and acellular components, such as exosomes and cytokines. This review focuses on the effects of virus-related components secreted by tumor cells over the TME in several virus-associated cancers.

A secretory form of Parkin-independent mitophagy contributes to the repertoire of extracellular vesicles released into the tumour interstitial fluid in vivo

We characterized the in vivo interstitial fluid (IF) content of extracellular vesicles (EVs) using the GFP-4T1 syngeneic murine cancer model to study EVs in-transit to the draining lymph node. GFP labelling confirmed the IF EV tumour cell origin. Molecular analysis revealed an abundance of IF EV-associated proteins specifically involved in mitophagy and secretory autophagy. A set of proteins required for sequential steps of fission-induced mitophagy preferentially populated the CD81+/PD-L1+ IF EVs; PINK1, TOM20, and ARIH1 E3 ubiquitin ligase (required for Parkin-independent mitophagy), DRP1 and FIS1 (mitochondrial peripheral fission), VDAC-1 (ubiquitination state triggers mitophagy away from apoptosis), VPS35, SEC22b, and Rab33b (vacuolar sorting). Comparing in vivo IF EVs to in vitro EVs revealed 40% concordance, with an elevation of mitophagy proteins in the CD81+ EVs for both murine and human cell lines subjected to metabolic stress. The export of cellular mitochondria proteins to CD81+ EVs was confirmed by density gradient isolation from the bulk EV isolate followed by anti-CD81 immunoprecipitation, molecular sieve chromatography, and MitoTracker export into CD81+ EVs. We propose the 4T1 in vivo model as a versatile tool to functionally characterize IF EVs. IF EV export of fission mitophagy proteins has broad implications for mitochondrial function and cellular immunology.

The Expression of Tax and HBZ Genes in Serum-Derived Extracellular Vesicles From HTLV-1 Carriers Correlates to Proviral Load and Inflammatory Markers

Human T-lymphotropic virus 1 (HTLV-1) is the etiologic agent of adult cell leukemia/lymphoma (ATL) and HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP). One of the major questions in HTLV-1 studies is related to the understanding of causes that lead to different clinical manifestations. However, it is well known that the viral genes tax and HTLV-1 basic leucine zipper factor (HBZ) are related to viral infectivity and the development of neurological and hematological diseases. Currently, there is evidence that HTLV-1 infected cells can release small extracellular vesicles (sEVs) involved in the mechanisms of viral particles spreading. Therefore, we evaluated the expression levels of tax and HBZ viral transcripts in serum-derived sEVs from HTLV-1 carriers, as well as the role of these vesicles in the modulation of the immune response. Three HAM/TSP carriers presented detectable levels of tax and HBZ transcripts in sEVs and were positively correlated to the proviral load (PVL) in peripheral blood mononuclear cells (PBMCs). The viral transcripts were only detectable in individuals with a PVL higher than 6,000/10⁵ PBMCs. Additionally, it was observed that HBZ presented a 2–12-folds increase over tax expression units. Gene expression and secretory protein analysis indicated that PBMCs from blood donors and HTLV-1 carriers exposed to increasing doses of tax+ HBZ+ sEVs showed a dose-dependent increase in interferon (IFN)-γ and interleukin (IL)-8 transcripts and proteins. Interestingly, the increase in IL-8 levels was close to those seen in HTLV-1-infected PBMCs with high PVL. Taken together, these findings indicate that the expression of viral transcripts in serum-derived sEVs of HTLV-1 carriers is related to the PVL presented by the infected individual. Additionally, tax+ HBZ+ sEVs can induce the production of inflammatory cytokines in patients with low PVL, which may be related to the development of symptoms in HTLV-1 infection.

Exosomes from H5N1 avian influenza virus-infected chickens regulate antiviral immune responses of chicken immune cells

Exosomes (membrane-derived vesicles) enable intracellular communication by delivering lipids, proteins, DNA, and RNA from one cell to another. Highly pathogenic avian influenza virus (HPAIV) H5N1 causes considerable economic loss in the poultry industry and poses a public health concern. The host innate immune system defends against H5N1 infection by activating antiviral immune responses. This study aimed to demonstrated that immunomodulatory effects of exosomes from HPAIV H5N1-infected White Leghorn chickens on chicken macrophages, fibroblasts, T cell, and B cell lines. The expression of type I interferons (IFN-α and -β) were highly upregulated in immune-related cell lines after treatment with exosomes derived from H5N1-infected chickens. Levels of pro-inflammatory cytokines, such as IFN-γ, IL-1β, and CXCL8, were also elevated by the exosomes. The mitogen-activated protein kinase (MAPK) signaling pathway was stimulated in immune-related cells by such exosomes via phosphorylation of extracellular regulated kinases 1/2 and p38 signaling molecules. Furthermore, the H5N1 viral proteins, nucleoprotein (NP) and non-structural protein (NS1), were packaged in exosomes and successfully transferred to non-infected immune-related cells. Therefore, exosomes from H5N1-infected chickens induced pro-inflammatory cytokine expression and stimulated the MAPK signaling pathway by delivering key viral proteins. These findings would aid better understanding of the mechanism underlying the modulation of antiviral immune responses of host immune-related cells by viral-protein-carrying exosomes and support their further application as a novel exosome-based H5N1 AIV vaccine platform.

Cannabinoids Reduce Extracellular Vesicle Release from HIV-1 Infected Myeloid Cells and Inhibit Viral Transcription

Of the 37.9 million individuals infected with human immunodeficiency virus type 1 (HIV-1), approximately 50% exhibit HIV-associated neurocognitive disorders (HAND). We and others previously showed that HIV-1 viral RNAs, such as trans-activating response (TAR) RNA, are incorporated into extracellular vesicles (EVs) and elicit an inflammatory response in recipient naïve cells. Cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC), the primary cannabinoids present in cannabis, are effective in reducing inflammation. Studies show that cannabis use in people living with HIV-1 is associated with lower viral load, lower circulating CD16+ monocytes and high CD4+ T-cell counts, suggesting a potentially therapeutic application. Here, HIV-1 infected U1 monocytes and primary macrophages were used to assess the effects of CBD. Post-CBD treatment, EV concentrations were analyzed using nanoparticle tracking analysis. Changes in intracellular and EV-associated viral RNA were quantified using RT-qPCR, and changes in viral proteins, EV markers, and autophagy proteins were assessed by Western blot. Our data suggest that CBD significantly reduces the number of EVs released from infected cells and that this may be mediated by reducing viral transcription and autophagy activation. Therefore, CBD may exert a protective effect by alleviating the pathogenic effects of EVs in HIV-1 and CNS-related infections.

Retroviral infection of human neurospheres and use of stem Cell EVs to repair cellular damage

HIV-1 remains an incurable infection that is associated with substantial economic and epidemiologic impacts. HIV-associated neurocognitive disorders (HAND) are commonly linked with HIV-1 infection; despite the development of combination antiretroviral therapy (cART), HAND is still reported to affect at least 50% of HIV-1 infected individuals. It is believed that the over-amplification of inflammatory pathways, along with release of toxic viral proteins from infected cells, are primarily responsible for the neurological damage that is observed in HAND; however, the underlying mechanisms are not well-defined. Therefore, there is an unmet need to develop more physiologically relevant and reliable platforms for studying these pathologies. In recent years, neurospheres derived from induced pluripotent stem cells (iPSCs) have been utilized to model the effects of different neurotropic viruses. Here, we report the generation of neurospheres from iPSC-derived neural progenitor cells (NPCs) and we show that these cultures are permissive to retroviral (e.g. HIV-1, HTLV-1) replication. In addition, we also examine the potential effects of stem cell derived extracellular vesicles (EVs) on HIV-1 damaged cells as there is abundant literature supporting the reparative and regenerative properties of stem cell EVs in the context of various CNS pathologies. Consistent with the literature, our data suggests that stem cell EVs may modulate neuroprotective and anti-inflammatory properties in damaged cells. Collectively, this study demonstrates the feasibility of NPC-derived neurospheres for modeling HIV-1 infection and, subsequently, highlights the potential of stem cell EVs for rescuing cellular damage induced by HIV-1 infection.

Nanotraps based on multifunctional materials for trapping and enrichment

Many biomarkers for early diagnosis of cancer and other diseases are difficult to detect because they often exist in body fluids in very low concentrations and are masked by high-abundance proteins such as albumin and immunoglobulins. At the same time, water pollution is one of the most serious environmental problems, but the existing adsorption materials have many shortcomings such as slow kinetics, small adsorption capacity and low adsorption efficiency. Nanotraps, mixed with gases or liquids, can capture and concentrate target substances, such as biomolecules, metal ions and oxoanions. Using nanotraps is a versatile sample pre-processing approach and it can improve the sensitivity of downstream analysis techniques. Herein, the preparations and applications of different types of nanotraps are mainly introduced. What's more, the shortcomings of using nanotraps in practical applications are also discussed. Using nanotraps is a promising sample pre-processing technology, which is of great significance for biomarkers discovery, diseases diagnosis, sewage purification and valuable ions recovery. STATEMENT OF SIGNIFICANCE: This review collates and summarizes the preparations and applications of different types of nanotraps, and discusses the shortcomings of using nanotraps in practical applications. Nanotraps, mixed with gases or liquids, can capture and concentrate target materials, such as biomolecules, metal ions and oxoanions. Using nanotraps is a versatile sample pre-processing approach and it can improve the sensitivity of downstream analysis techniques. During the COVID-19 pandemic, hydrogel nanotraps were successfully utilized for RT-PCR analysis with the FDA Emergency Used Authorization for COVID-19. Using nanotraps is a promising sample pre-processing technology, which is of great significance for biomarkers discovery, diseases diagnosis, sewage purification and valuable ions recovery.

Extracellular Vesicles as a New Promising Therapy in HIV Infection

Combination antiretroviral therapy (cART) effectively blocks HIV replication but cannot completely eliminate HIV from the body mainly due to establishment of a viral reservoir. To date, clinical strategies designed to replace cART for life and alternatively to eliminate the HIV reservoir have failed. The reduced expression of viral antigens in the latently infected cells is one of the main reasons behind the failure of the strategies to purge the HIV reservoir. This situation has forced the scientific community to search alternative therapeutic strategies to control HIV infection. In this regard, recent findings have pointed out extracellular vesicles as therapeutic agents with enormous potential to control HIV infection. This review focuses on their role as pro-viral and anti-viral factors, as well as their potential therapeutic applications.

Antenatal and postpartum immunological markers levels in women with HIV infection and malnutrition in a low resource setting: A pilot study

Objectives: Both, Human Immunodeficiency Virus (HIV) infection and malnutrition are major challenges in pregnancy and postpartum in low-resource settings and the respective cytokine levels remain poorly described. The main objectives of this study were to find immune markers that are associated with HIV infection and malnutrition in pregnant women and to determine how these would change at 14 weeks postpartum.Method: Pregnant women of at least 20 weeks gestational age were enrolled into this longitudinal observational single centre pilot study at 4 primary health clinics in high-density areas around Harare, Zimbabwe. Socio-demographic and clinical data including plasma samples were collected in pregnancy and 14 weeks postpartum (PP). Mid-upper-arm circumference (MUAC) ≤23 cm was used as an indicator for malnourishment. Fifty-six cytokines and chemokines were assayed in plasma using the Mesoscale multiplex assay. We determined cytokine/chemokine levels including markers for vascular injury in HIV-infection and malnutrition. Associations remaining significant after multiple test correction were confirmed in multivariable analyses after controlling for confounders.Results: Ninety-seven pregnant women were recruited for this study and from these, 44 were randomly selected for cytokine assaying of which 20 HIV infected, 15 malnourished, and 9 well-nourished HIV uninfected participants. HIV infection was associated with significantly higher interleukin (IL)-4 ( q < 0.05) and IL-10 ( q < 0.001) in pregnancy. Longitudinally, IL-4 ( q < 0.01) and IL-10 ( q < 0.001) significantly increased in HIV uninfected women whilst in the HIV-infected both were non-significantly decreased. IL-8 (q < 0.05) levels significantly increased in HIV-infected women from pregnancy to 14 weeks PP. Vascular Cell Adhesion Molecule 1 (VCAM-1) ( q < 0.05) and interleukin-1 receptor antagonist (IL-1RA) ( q < 0.05) were significantly lower in malnourished women in pregnancy and 14 weeks PP, respectively. Conclusions: IL-4, IL-8, IL-10, and VCAM-1 are potential biomarkers for monitoring immune functioning in HIV-infected pregnant women and malnutrition. However, studies with larger sample size are warranted to confirm these findings.

Exosomes: Emerging implementation of nanotechnology for detecting and managing novel corona virus- SARS-CoV-2

The spread of SARS-CoV-2 as an emerging novel coronavirus disease (COVID-19) had progressed as a worldwide pandemic since the end of 2019. COVID-19 affects firstly lungs tissues which are known for their very slow regeneration. Afterwards, enormous cytokine stimulation occurs in the infected cells immediately after a lung infection which necessitates good management to save patients. Exosomes are extracellular vesicles of nanometric size released by reticulocytes on maturation and are known to mediate intercellular communications. The exosomal cargo serves as biomarkers in diagnosing various diseases; moreover, exosomes could be employed as nanocarriers in drug delivery systems. Exosomes look promising to combat the current pandemic since they contribute to the immune response against several viral pathogens. Many studies have proved the potential of using exosomes either as viral elements or host systems that acquire immune-stimulatory effects and could be used as a vaccine or drug delivery tool. It is essential to stop viral replication, prevent and reverse the massive storm of cytokine that worsens the infected patients' situations for the management of COVID-19. The main benefits of exosomes could be; no cells will be introduced, no chance of mutation, lack of immunogenicity and the damaged genetic material that could negatively affect the recipient is avoided. Additionally, it was found that exosomes are static with no ability for in vivo reproduction. The current review article discusses the possibilities of using exosomes for detecting novel coronavirus and summarizes state of the art concerning the clinical trials initiated for examining the use of COVID-19 specific T cells derived exosomes and mesenchymal stem cells derived exosomes in managing COVID-19.

Exogenous and Endogenous Dendritic Cell-Derived Exosomes: Lessons Learned for Immunotherapy and Disease Pathogenesis

Immune therapeutic exosomes, derived exogenously from dendritic cells (DCs), the 'directors' of the immune response, are receiving favorable safety and tolerance profiles in phase I and II clinical trials for a growing number of inflammatory and neoplastic diseases. DC-derived exosomes (EXO), the focus of this review, can be custom tailored with immunoregulatory or immunostimulatory molecules for specific immune cell targeting. Moreover, the relative stability, small size and rapid uptake of EXO by recipient immune cells offer intriguing options for therapeutic purposes. This necessitates an in-depth understanding of mechanisms of EXO biogenesis, uptake and routing by recipient immune cells, as well as their in vivo biodistribution. Against this backdrop is recognition of endogenous exosomes, secreted by all cells, the molecular content of which is reflective of the metabolic state of these cells. In this regard, exosome biogenesis and secretion is regulated by cell stressors of chronic inflammation and tumorigenesis, including dysbiotic microbes, reactive oxygen species and DNA damage. Such cell stressors can promote premature senescence in young cells through the senescence associated secretory phenotype (SASP). Pathological exosomes of the SASP amplify inflammatory signaling in stressed cells in an autocrine fashion or promote inflammatory signaling to normal neighboring cells in paracrine, without the requirement of cell-to-cell contact. In summary, we review relevant lessons learned from the use of exogenous DC exosomes for immune therapy, as well as the pathogenic potential of endogenous DC exosomes.

Exosomes originating from infection with the cytoplasmic single-stranded RNA virus Rift Valley fever virus (RVFV) protect recipient cells by inducing RIG-I mediated IFN-B response that leads to activation of autophagy

Background

Although multiple studies have demonstrated a role for exosomes during virus infections, our understanding of the mechanisms by which exosome exchange regulates immune response during viral infections and affects viral pathogenesis is still in its infancy. In particular, very little is known for cytoplasmic single-stranded RNA viruses such as SARS-CoV-2 and Rift Valley fever virus (RVFV). We have used RVFV infection as a model for cytoplasmic single-stranded RNA viruses to address this gap in knowledge. RVFV is a highly pathogenic agent that causes RVF, a zoonotic disease for which no effective therapeutic or approved human vaccine exist.

Results

We show here that exosomes released from cells infected with RVFV (designated as EXi-RVFV) serve a protective role for the host and provide a mechanistic model for these effects. Our results show that treatment of both naïve immune cells (U937 monocytes) and naïve non-immune cells (HSAECs) with EXi-RVFV induces a strong RIG-I dependent activation of IFN-B. We also demonstrate that this strong anti-viral response leads to activation of autophagy in treated cells and correlates with resistance to subsequent viral infection. Since we have shown that viral RNA genome is associated with EXi-RVFV, RIG-I activation might be mediated by the presence of packaged viral RNA sequences.

Conclusions

Using RVFV infection as a model for cytoplasmic single-stranded RNA viruses, our results show a novel mechanism of host protection by exosomes released from infected cells (EXi) whereby the EXi activate RIG-I to induce IFN-dependent activation of autophagy in naïve recipient cells including monocytes. Because monocytes serve as reservoirs for RVFV replication, this EXi-RVFV-induced activation of autophagy in monocytes may work to slow down or halt viral dissemination in the infected organism. These findings offer novel mechanistic insights that may aid in future development of effective vaccines or therapeutics, and that may be applicable for a better molecular understanding of how exosome release regulates innate immune response to other cytoplasmic single-stranded RNA viruses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-021-00732-z.

Regulating the production and biological function of small extracellular vesicles: current strategies, applications and prospects

Numerous studies have confirmed the great application potentials of small extracellular vesicles (sEVs) in biological medical field, especially in tissue repair and regeneration. However, the production capability of sEVs by noncancerous cells is very limited, while their dosage requirements in disease treatments are usually very high. Meanwhile, as cell aging, the sEV production capability of cells decreases and the biological function of sEVs changes accordingly. In addition, for special applications, sEVs carrying desired bioactive substances should be designed to perform their expected biological function. Therefore, improving the production of sEVs and precisely regulating their biological function are of great significance for promoting the clinical applications of sEVs. In this review, some of the current classic strategies in affecting the cellular behaviors of donor cells and subsequently regulating the production and biological function of their sEVs are summarized, including gene engineering methods, stress-inducing conditions, chemical regulators, physical methods, and biomaterial stimulations. Through applying these strategies, increased yield of sEVs with required biological function can be obtained for disease treatment and tissue repair, such as bone regeneration, wound healing, nerve function recovery and cancer treatment, which could not only reduce the harvest cost of sEV but promote the practical applications of sEVs in clinic.