Anti-SARS-CoV-2 Activity of Extracellular Vesicle Inhibitors: Screening, Validation, and Combination with Remdesivir

Unlocking the potential of remdesivir: innovative approaches to drug delivery

Given the recurrent waves of COVID-19 and the emergence of new viral infections, optimizing the potential of remdesivir as an antiviral agent is critical. While several reviews have explored the efficacy of remdesivir, few have comprehensively addressed its challenges, such as the necessity for intravenous infusion, suboptimal lung accumulation, and safety concerns related to its formulation. This review critically examines these challenges while proposing innovative solutions and effective combinations with other antiviral agents and repurposed drugs. By highlighting the role of complex generics, we aim to enhance therapeutic efficacy in ways not previously discussed in existing literature. Furthermore, we address the development of novel drug delivery systems which specifically aim to improve remdesivir's pharmacological profile. By analyzing recent findings, we assess both the successes and limitations of current approaches, providing insights into ongoing challenges and strategies for further optimization. This review uniquely focuses on targeted drug delivery systems and innovative formulations, thereby maximizing remdesivir's therapeutic benefits and broadening its application in combating emerging viral threats. In doing so, we fill a critical gap in literature, offering a comprehensive overview that informs future research and clinical strategies.

The next viral pandemic-where do we stand?

The world is presently undergoing a recovery phase following the unexpected challenges posed by the coronavirus disease 2019 (COVID-19) pandemic. The loss of lives and the economic setbacks experienced by the global population will require considerable time to address. It is clear that future outbreaks, epidemics, or even pandemic caused by unknown bacterial, fungal, or viral pathogens are inevitable. In this context, public health front-liners will be essential in minimizing the impact of such incidents. This mini-review briefly discusses sociocultural issues, diagnostic capacities, surveillance, and screening strategies for potential future viral pandemic - referred to as Pandemic X. Additionally, it addresses treatment responses, vaccine development efforts, scientific advancements, policy considerations, and prospects for science communication related to forthcoming viral pandemics. While this review does not encompass all scientific approaches available on these topics, it aims to serve as a guideline for informing public health sectors about appropriate measures that should be undertaken.

Dual Role of Extracellular Vesicles as Orchestrators of Emerging and Reemerging Virus Infections

Current decade witnessed the emergence and re-emergence of many viruses, which affected public health significantly. Viruses mainly utilize host cell machinery to promote its growth, and spread of these diseases. Numerous factors influence virus-host cell interactions, of which extracellular vesicles play an important role, where they transfer information both locally and distally by enclosing viral and host-derived proteins and RNAs as their cargo. Thus, they play a dual role in mediating virus infections by promoting virus dissemination and evoking immune responses in host organisms. Moreover, it acts as a double-edged sword during these infections. Advances in extracellular vesicles regulating emerging and reemerging virus infections, particularly in the context of SARS-CoV-2, Dengue, Ebola, Zika, Chikungunya, West Nile, and Japanese Encephalitis viruses are discussed in this review.

Advancements in the preparation technology of small molecule artificial antigens and their specific antibodies: a comprehensive review

Small molecules find extensive application in medicine, food safety, and environmental studies, particularly in biomedicine. Immunoassay technology, leveraging the specific recognition between antigens and antibodies, offers a superior alternative to traditional physical and chemical analysis methods. This approach allows for the rapid and accurate detection of small molecular compounds, owing to its high sensitivity, specificity, and swift analytical capabilities. However, small molecular compounds often struggle to effectively stimulate an immune response due to their low molecular weight, weak antigenicity, and limited antigenic epitopes. To overcome this, coupling small molecule compounds with macromolecular carriers to form complete antigens is typically required to induce specific antibodies in animals. Consequently, the preparation of small-molecule artificial antigens and the production of efficient specific antibodies are crucial for achieving precise immunoassays. This paper reviews recent advancements in small molecule antibody preparation technology, emphasizing the design and synthesis of haptens, the coupling of haptens with carriers, the purification and identification of artificial antigens, and the preparation of specific antibodies. Additionally, it evaluates the current technological shortcomings and limitations while projecting future trends in artificial antigen synthesis and antibody preparation technology.

Exosomes, and the potential for exosome-based interventions against COVID-19

Since late 2019, the world has been devastated by the coronavirus disease 2019 (COVID-19) induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with more than 760 million people affected and ∼seven million deaths reported. Although effective treatments for COVID-19 are currently limited, there has been a strong focus on developing new therapeutic approaches to address the morbidity and mortality linked to this disease. An approach that is currently being investigated is the use of exosome-based therapies. Exosomes are small, extracellular vesicles that play a role in many clinical diseases, including viral infections, infected cells release exosomes that can transmit viral components, such as miRNAs and proteins, and can also include receptors for viruses that facilitate viral entry into recipient cells. SARS-CoV-2 has the ability to impact the formation, secretion, and release of exosomes, thereby potentially facilitating or intensifying the transmission of the virus among cells, tissues and individuals. Therefore, designing synthetic exosomes that carry immunomodulatory cargo and antiviral compounds are proposed to be a promising strategy for the treatment of COVID-19 and other viral diseases. Moreover, exosomes generated from mesenchymal stem cells (MSC) might be employed as cell-free therapeutic agents, as MSC-derived exosomes can diminish the cytokine storm and reverse the suppression of host anti-viral defences associated with COVID-19, and boost the repair of lung damage linked to mitochondrial activity. The present article discusses the significance and roles of exosomes in COVID-19, and explores potential future applications of exosomes in combating this disease. Despite the challenges posed by COVID-19, exosome-based therapies could represent a promising avenue for improving patient outcomes and reducing the impact of this disease.

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.

Placenta-Derived Extracellular Vesicles in Pregnancy Complications and Prospects on a Liquid Biopsy for Hemoglobin Bart's Disease

Extracellular vesicles (EVs) are nano-scaled vesicles released from all cell types into extracellular fluids and specifically contain signature molecules of the original cells and tissues, including the placenta. Placenta-derived EVs can be detected in maternal circulation at as early as six weeks of gestation, and their release can be triggered by the oxygen level and glucose concentration. Placental-associated complications such as preeclampsia, fetal growth restriction, and gestational diabetes have alterations in placenta-derived EVs in maternal plasma, and this can be used as a liquid biopsy for the diagnosis, prediction, and monitoring of such pregnancy complications. Alpha-thalassemia major ("homozygous alpha-thalassemia-1") or hemoglobin Bart's disease is the most severe form of thalassemia disease, and this condition is lethal for the fetus. Women with Bart's hydrops fetalis demonstrate signs of placental hypoxia and placentomegaly, thereby placenta-derived EVs provide an opportunity for a non-invasive liquid biopsy of this lethal condition. In this article, we introduced clinical features and current diagnostic markers of Bart's hydrops fetalis, extensively summarize the characteristics and biology of placenta-derived EVs, and discuss the challenges and opportunities of placenta-derived EVs as part of diagnostic tests for placental complications focusing on Bart's hydrop fetalis.

Pathogenesis and Mechanisms of SARS-CoV-2 Infection in the Intestine, Liver, and Pancreas

The novel coronavirus, SARS-CoV-2, rapidly spread worldwide, causing an ongoing global pandemic. While the respiratory system is the most common site of infection, a significant number of reported cases indicate gastrointestinal (GI) involvement. GI symptoms include anorexia, abdominal pain, nausea, vomiting, and diarrhea. Although the mechanisms of GI pathogenesis are still being examined, viral components isolated from stool samples of infected patients suggest a potential fecal-oral transmission route. In addition, viral RNA has been detected in blood samples of infected patients, making hematologic dissemination of the virus a proposed route for GI involvement. Angiotensin-converting enzyme 2 (ACE2) receptors serve as the cellular entry mechanism for the virus, and these receptors are particularly abundant throughout the GI tract, making the intestine, liver, and pancreas potential extrapulmonary sites for infection and reservoirs sites for developing mutations and new variants that contribute to the uncontrolled spread of the disease and resistance to treatments. This transmission mechanism and the dysregulation of the immune system play a significant role in the profound inflammatory and coagulative cascades that contribute to the increased severity and risk of death in several COVID-19 patients. This article reviews various potential mechanisms of gastrointestinal, liver, and pancreatic injury.

Comparison of viral inactivation methods on the characteristics of extracellular vesicles from SARS-CoV-2 infected human lung epithelial cells

The interaction of SARS-CoV-2 infection with extracellular vesicles (EVs) is of particular interest at the moment. Studying SARS-CoV-2 contaminated-EV isolates in instruments located outside of the biosafety level-3 (BSL-3) environment requires knowing how viral inactivation methods affect the structure and function of extracellular vesicles (EVs). Therefore, three common viral inactivation methods, ultraviolet-C (UVC; 1350 mJ/cm2 ), β-propiolactone (BPL; 0.005%), heat (56°C, 45 min) were performed on defined EV particles and their proteins, RNAs, and function. Small EVs were isolated from the supernatant of SARS-CoV-2-infected human lung epithelial Calu-3 cells by stepwise centrifugation, ultrafiltration and qEV size-exclusion chromatography. The EV isolates contained SARS-CoV-2. UVC, BPL and heat completely abolished SARS-CoV-2 infectivity of the contaminated EVs. Particle detection by electron microscopy and nanoparticle tracking was less affected by UVC and BPL than heat treatment. Western blot analysis of EV markers was not affected by any of these three methods. UVC reduced SARS-CoV-2 spike detectability by quantitative RT-PCR and slightly altered EV-derived β-actin detection. Fibroblast migration-wound healing activity of the SARS-CoV-2 contaminated-EV isolate was only retained after UVC treatment. In conclusion, specific viral inactivation methods are compatible with specific measures in SARS-CoV-2 contaminated-EV isolates. UVC treatment seems preferable for studying functions of EVs released from SARS-CoV-2 infected cells.

Therapeutic use of calpeptin in COVID-19 infection

This perspective considers the benefits of the potential future use of the cell permeant calpain inhibitor, calpeptin, as a drug to treat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Recent work has reported calpeptin’s capacity to inhibit entry of the virus into cells. Elsewhere, several drugs, including calpeptin, were found to be able to inhibit extracellular vesicle (EV) biogenesis. Unsurprisingly, because of similarities between viral and EV release mechanisms, calpeptin has also been shown to inhibit viral egress. This approach, identifying calpeptin, through large-scale screening studies as a candidate drug to treat COVID-19, however, has not considered the longer term likely benefits of calpain inhibition, post-COVID-19. This perspective will reflect on the capacity of calpeptin for treating long COVID by inhibiting the overproduction of neutrophil extracellular traps potentially damaging lung cells and promoting clotting, together with limiting associated chronic inflammation, tissue damage and pulmonary fibrosis. It will also reflect on the tolerated and detrimental in vivo side-effects of calpain inhibition from various preclinical studies.

Action Mechanisms of Small Extracellular Vesicles in Inflammaging

The accumulation process of proinflammatory components in the body due to aging influences intercellular communication and is known as inflammaging. This biological mechanism relates the development of inflammation to the aging process. Recently, it has been reported that small extracellular vesicles (sEVs) are mediators in the transmission of paracrine senescence involved in inflammatory aging. For this reason, their components, as well as mechanisms of action of sEVs, are relevant to develop a new therapy called senodrugs (senolytics and senomorphic) that regulates the intercellular communication of inflammaging. In this review, we include the most recent and relevant studies on the role of sEVs in the inflammatory aging process and in age-related diseases such as cancer and type 2 diabetes.

Human Milk Oligosaccharides: Potential Applications in COVID-19

Coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) has become a global health crisis with more than four million deaths worldwide. A substantial number of COVID-19 survivors continue suffering from long-COVID syndrome, a long-term complication exhibiting chronic inflammation and gut dysbiosis. Much effort is being expended to improve therapeutic outcomes. Human milk oligosaccharides (hMOS) are non-digestible carbohydrates known to exert health benefits in breastfed infants by preventing infection, maintaining immune homeostasis and nurturing healthy gut microbiota. These beneficial effects suggest the hypothesis that hMOS might have applications in COVID-19 as receptor decoys, immunomodulators, mucosal signaling agents, and prebiotics. This review summarizes hMOS biogenesis and classification, describes the possible mechanisms of action of hMOS upon different phases of SARS-CoV-2 infection, and discusses the challenges and opportunities of hMOS research for clinical applications in COVID-19.