Antiviral bioactivity of resveratrol against Zika virus infection in human retinal pigment epithelial cells

Resveratrol inhibits African swine fever virus replication via the Nrf2-mediated reduced glutathione and antioxidative activities

African swine fever (ASF) is a highly contagious and severe infectious disease caused by African swine fever virus (ASFV). The disease significantly threatens the sustainable development of the global pig industry. Unfortunately, to date, no safe and efficacious vaccines are commercially available except in Vietnam. Antioxidative stress is a critical factor in antiviral strategies. In this study, we show that ASFV infection elevates the level of reactive oxygen species (ROS) and suppresses the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway in vitro and in vivo. Moreover, overexpressing Nrf2 can significantly inhibit ASFV replication. Through high-throughput screening of natural small molecules against ASFV, we identify resveratrol (RES), an Nrf2 activator, as a compound capable of inducing the cellular antiviral responses and effectively inhibiting ASFV replication in primary porcine alveolar macrophages (PAMs). Notably, untargeted metabolomics profiling reveals that glutathione emerges as a primary differential metabolite related to the antiviral activities of RES against ASFV. Mechanistically, RES exerts its antiviral effects and attenuates the elevated level of ROS caused by ASFV infection by inducing the production of reduced glutathione (GSH) via the activation of the Nrf2 signaling pathway. In conclusion, RES exhibits broad efficacy as a potentially effective compound for inhibiting ASFV infection and alleviating the oxidative stress induced by ASFV infection via the Nrf2 signaling pathway.

The Essential Role of Mitochondrial Dynamics in Viral Infections

Mitochondria are dynamic organelles that play crucial roles in energy production, metabolic balance, calcium homeostasis, apoptosis, and innate immunity, and are key determinants of cell fate. They are also targets for viral invasion of the body. Many viral proteins target mitochondria, controlling mitochondrial morphology, metabolism, and immune response, thereby achieving immune evasion, promoting their proliferation, and accelerating the infection process. Mitochondrial quality control is key to maintaining normal physiological functions and mitochondrial homeostasis. Dysregulation of mitochondrial dynamics is closely related to the development of many diseases. New roles of mitochondrial dynamics in viral infection are constantly being discovered. Viruses change mitochondrial dynamics by targeting mitochondria to achieve a persistent state of infection. Currently, understanding of mitochondrial dynamics during viral infection is limited. Research on the impact of viral proteins on mitochondrial dynamics provides a foundation for investigating the pathogenesis of viral infections, the disease process, and identifying potential therapeutic targets. This review focuses on the connection between viral infection and mitochondrial dynamics and priority areas for research on virus-mediated mitochondrial immunity, provides insight into the regulation of mitochondrial dynamics by viruses targeting mitochondria, and explores potential means of mitochondrial-mediated control and treatment of viral diseases.

Alteration of mitochondrial function in arthropods during arboviruses infection: a review of the literature

Arthropods serve as vectors for numerous arboviruses responsible for diseases worldwide. Despite their medical, veterinary, and economic significance, the interaction between arboviruses and arthropods remains poorly understood. Mitochondria in arthropods play a crucial role by supplying energy for cell survival and viral replication. Some arboviruses can replicate within arthropod vectors without harming the host. Successful transmission depends on efficient viral replication in the vector's tissues, ultimately reaching the salivary glands for transmission to a vertebrate host, including humans, via blood-feeding. This review summarizes current knowledge of mitochondrial function in arthropods during arbovirus infection, highlighting gaps compared to studies in mammals and other pathogens relevant to arthropods. It emphasizes mitochondrial processes in insects that require further investigation to uncover the mechanisms underlying arthropod-borne transmission.

An Overview of Zika Virus and Zika Virus Induced Neuropathies

Flaviviruses pose a major public health concern across the globe. Among them, Zika virus (ZIKV) is an emerging and reemerging arthropod-borne flavivirus that has become a major international public health problem following multiple large outbreaks over the past two decades. The majority of infections caused by ZIKV exhibit mild symptoms. However, the virus has been found to be associated with a variety of congenital neural abnormalities, including microcephaly in children and Guillain-Barre syndrome in adults. The exact prediction of the potential of ZIKV transmission is still enigmatic and underlines the significance of routine detection of the virus in suspected areas. ZIKV transmission from mother to fetus (including fetal abnormalities), viral presence in immune-privileged areas, and sexual transmission demonstrate the challenges in understanding the factors governing viral persistence and pathogenesis. This review illustrates the transmission patterns, epidemiology, control strategies (through vaccines, antivirals, and vectors), oncolytic aspects, molecular insights into neuro-immunopathogenesis, and other neuropathies caused by ZIKV. Additionally, we summarize in vivo and in vitro models that could provide an important platform to study ZIKV pathogenesis and the underlying governing cellular and molecular mechanisms.

The aryl hydrocarbon receptor: A crucial mediator in ocular disease pathogenesis and therapeutic target

The aryl hydrocarbon receptor (AHR) is a pivotal nuclear receptor involved in mediating cellular responses to a wide range of environmental pollutants and endogenous ligands. AHR plays a central role in regulating essential physiological processes, including xenobiotic metabolism, immune response modulation, cell cycle control, tumorigenesis, and developmental events. Recent studies have identified AHR as a critical mediator and a potential therapeutic target in the pathogenesis of ocular diseases. This review provides a thorough analysis of the various functions of AHR signalling in the ocular environment, with a specific emphasis on its effects on the retina, retinal pigment epithelium (RPE), choroid, and cornea. We provide a detailed discussion on the molecular mechanisms through which AHR integrates environmental and endogenous signals, influencing the development and progression of age-related macular degeneration (AMD), retinitis pigmentosa, uveitis, and other major ocular disorders. Furthermore, we evaluate the therapeutic potential of modulating AHR activity through novel ligands and agonists as a strategy for treating eye diseases. Understanding the molecular mechanisms of AHR in ocular tissues may facilitate the development of AHR-targeted therapies, which is crucial for addressing the pressing clinical demand for novel treatment strategies in ocular diseases.

Broad-Spectrum Antiviral Effect of Cannabidiol Against Enveloped and Nonenveloped Viruses

Introduction: Cannabidiol (CBD), the main non-psychoactive cannabinoid of the Cannabis sativa plant, is a powerful antioxidant compound that in recent years has increased interest due to causes effects in a wide range of biological functions. Zika virus (ZIKV) is a virus transmitted mainly by the Aedes aegypti mosquitoes, which causes neurological diseases, such as microcephaly and Guillain-Barre syndrome. Although the frequency of viral outbreaks has increased recently, no vaccinations or particular chemotherapeutic treatments are available for ZIKV infection. Objectives: The major aim of this study was to explore the in vitro antiviral activity of CBD against ZIKV, expanding also to other dissimilar viruses. Materials and Methods: Cell cultures were infected with enveloped and nonenveloped viruses and treated with non-cytotoxic concentrations of CBD and then, viral titers were determined. Additionally, the mechanism of action of the compound during ZIKV in vitro infections was studied. To study the possible immunomodulatory role of CBD, infected and uninfected Huh-7 cells were exposed to 10 μM CBD during 48 h and levels of interleukins 6 and 8 and interferon-beta (IFN-β) expression levels were measured. On the other hand, the effect of CBD on cellular membranes was studied. For this, an immunofluorescence assay was performed, in which cell membranes were labeled with wheat germ agglutinin. Finally, intracellular cholesterol levels were measured. Results: CBD exhibited a potent antiviral activity against all the tested viruses in different cell lines with half maximal effective concentration values (CE50) ranging from 0.87 to 8.55 μM. Regarding the immunomodulatory effect of CBD during ZIKV in vitro infections, CBD-treated cells exhibited significantly IFN-β increased levels, meanwhile, interleukins 6 and 8 were not induced. Furthermore, it was determined that CBD affects cellular membranes due to the higher fluorescence intensity that was observed in CBD-treated cells and lowers intracellular cholesterol levels, thus affecting the multiplication of ZIKV and other viruses. Conclusions: It was demonstrated that CBD inhibits structurally dissimilar viruses, suggesting that this phytochemical has broad-spectrum antiviral effect, representing a valuable alternative in emergency situations during viral outbreaks, like the one caused by severe acute respiratory syndrome coronavirus 2 in 2020.

Subconfluent ARPE-19 Cells Display Mesenchymal Cell-State Characteristics and Behave like Fibroblasts, Rather Than Epithelial Cells, in Experimental HCMV Infection Studies

Human cytomegalovirus (HCMV) has a broad cellular tropism and epithelial cells are important physiological targets during infection. The retinal pigment epithelial cell line ARPE-19 has been used to model HCMV infection in epithelial cells for decades and remains a commonly used cell type for studying viral entry, replication, and the cellular response to infection. We previously found that ARPE-19 cells, despite being derived from an epithelial cell explant, express extremely low levels of canonical epithelial proteins, such as E-cadherin and EpCAM. Here, we perform comparative studies of ARPE-19 and additional epithelial cell lines with strong epithelial characteristics. We find that ARPE-19 cells cultured under subconfluent conditions resemble mesenchymal fibroblasts, rather than epithelial cells; this is consistent with previous studies showing that ARPE-19 cultures require extended periods of high confluency culture to maintain epithelial characteristics. By reanalyzing public gene expression data and using machine learning, we find evidence that ARPE-19 cultures maintained across many labs exhibit mesenchymal characteristics and that the majority of studies employing ARPE-19 use them in a mesenchymal state. Lastly, by performing experimental HCMV infections across mesenchymal and epithelial cell lines, we find that ARPE-19 cells behave like mesenchymal fibroblasts, producing logarithmic yields of cell-free infectious progeny, while cell lines with strong epithelial character exhibit an atypical infectious cycle and naturally restrict the production of cell-free progeny. Our work highlights important characteristics of the ARPE-19 cell line and suggests that subconfluent ARPE-19 cells may not be optimal for modeling epithelial infection with HCMV or other human viruses. It also suggests that HCMV biosynthesis and/or spread may occur quite differently in epithelial cells compared to mesenchymal cells. These differences could contribute to viral persistence or pathogenesis in epithelial tissues.

Mitochondrial quality control: prime targets for antiviral therapy?

Mitochondrial quality control (MQC) plays a crucial role in maintaining mitochondrial health. Mitochondrial dynamics and mitophagy are two intricate processes of the MQC machinery acting at the organelle level to orchestrate mitochondrial homeostasis. Here, we discuss how viruses perturb these two processes to facilitate their infections and emphasize the rationale and challenges of therapeutically targeting MQC for treating viral diseases.

Chitosan-Based Nanogels Designed for Betanin-Rich Beetroot Extract Transport: Physicochemical and Biological Aspects

Nanotechnology has emerged as a possible solution to improve phytochemicals' limitations. The objective of the present study was to encapsulate beetroot extract (BR Ext) within a chitosan (CS)-based nanogel (NG) designed via ionic crosslinking with tripolyphosphate (TPP) for betanin (Bet) delivery, mainly in the ophthalmic environment. BR Ext is rich in betanin (Bet) according to thin layer chromatography (TLC), UV-visible spectroscopy, and HPLC analysis. NG presented a monodisperse profile with a size of 166 ± 6 nm and low polydispersity (0.30 ± 0.03). ζ potential (ζ-Pot) of +28 ± 1 is indicative of a colloidally stable system. BR Ext encapsulation efficiency (EE) was 45 ± 3%. TEM, with the respective 3D-surface plots and AFM, showed spherical-elliptical-shaped NG. The BR Ext release profile was biphasic with a burst release followed by slow and sustained phase over 12 h. Mucoadhesion assay demonstrated interactions between NG with mucin. Moreover, NG provided photoprotection and pH stability to BR Ext. FRAP and ABTS assays confirmed that BR Ext maintained antioxidant activity into NG. Furthermore, in vitro assays using human retinal cells displayed absence of cytotoxicity as well as an efficient protection against injury agents (LPS and H2O2). NGs are a promising platform for BR Ext encapsulation, exerting controlled release for ophthalmological use.

Natural Products and Derivatives as Potential Zika virus Inhibitors: A Comprehensive Review

Zika virus (ZIKV) is an arbovirus whose infection in humans can lead to severe outcomes. This article reviews studies reporting the anti-ZIKV activity of natural products (NPs) and derivatives published from 1997 to 2022, which were carried out with NPs obtained from plants (82.4%) or semisynthetic/synthetic derivatives, fungi (3.1%), bacteria (7.6%), animals (1.2%) and marine organisms (1.9%) along with miscellaneous compounds (3.8%). Classes of NPs reported to present anti-ZIKV activity include polyphenols, triterpenes, alkaloids, and steroids, among others. The highest values of the selectivity index, the ratio between cytotoxicity and antiviral activity (SI = CC₅₀/EC₅₀), were reported for epigallocatechin gallate (SI ≥ 25,000) and anisomycin (SI ≥ 11,900) obtained from Streptomyces bacteria, dolastane (SI = 1246) isolated from the marine seaweed Canistrocarpus cervicorni, and the flavonol myricetin (SI ≥ 862). NPs mostly act at the stages of viral adsorption and internalization in addition to presenting virucidal effect. The data demonstrate the potential of NPs for developing new anti-ZIKV agents and highlight the lack of studies addressing their molecular mechanisms of action and pre-clinical studies of efficacy and safety in animal models. To the best of our knowledge, none of the active compounds has been submitted to clinical studies.

Identification of desoxyrhapontigenin as a novel antiviral agent against congenital Zika virus infection

Zika virus (ZIKV) infection arises as a global health threat owing to its association with Guillain-Barre syndrome and microcephaly in adults and fetuses since the most recent epidemics. Although extraordinary efforts have been underway globally to identify safe and effective treatments for ZIKV, therapeutic progressions seem to remain stagnant, especially for treating congenital ZIKV infection. Bio-compounds from medicinal plants evolutionarily optimized as drug-like molecules offer eligible sources of pharmaceuticals and lead drugs to fight against viral infections. Here, we identified desoxyrhapontigenin (DES), a naturally occurring bioactive product, as the strongest inhibitory compound against ZIKV infection among six conventional polyphenols in vitro. We also leveraged the trophoblast cell line, human trophoblast stem cells, and complex placental organoid models to provide solid evidence to support the anti-ZIKV bioactivity of DES. Notably, DES treatment effectively reduced the ZIKV burden in serum and target tissues, and correspondingly improved ZIKV-induced pathologic changes including weight loss, tissue inflammation, cell apoptosis, and adverse pregnancy outcomes, while it did not lead to obvious toxicity in both adult and pregnant mice. Furthermore, mechanistic studies revealed that DES could suppress ZIKV entry via dual mechanisms of direct targeting ZIKV E proteins and downregulating putative ZIKV receptors. These findings elucidate a previously unappreciated protective role of desoxyrhapontigenin against ZIKV infection both in vitro and in vivo, which shed light on the development of a novel and potent treatment for congenital ZIKV infection.

Insights into the Anti-inflammatory and Antiviral Mechanisms of Resveratrol

Resveratrol is a naturally occurring stilbene phytoalexin phenolic compound, which has been extensively studied on its biological activity. It has been widely accepted that resveratrol possesses anti-inflammatory and antiviral activities. In this review, we summarize the anti-inflammatory dosages and mechanism and antiviral mechanism of resveratrol. Since viral infections are often accompanied by inflammation, we propose that the NF-κB signaling pathway is a key and common molecular mechanism of resveratrol to exert anti-inflammatory and antiviral effects. For future studies, we believe that resveratrol's anti-inflammatory and antiviral mechanisms can consider the upstream signaling molecules of the NF-κB signaling pathway. For resveratrol antivirus, future studies can be conducted on the interaction of resveratrol with key proteins or important enzymes of the virus. In addition, we also think that the clinical application of resveratrol is very important. In short, resveratrol is a promising anti-inflammatory and antiviral drug, and research on it needs to be expanded.