Pathogenesis of Zika Virus Infection

Silymarin exerts antioxidant and antiviral effects on Zika virus infection

The Zika virus (ZIKV) - Orthoflavivirus zikaense - epidemic and its association with severe neurological disorders have created an urgent need to understand the disease pathogenesis and identify potential therapeutic targets. In previous investigations, we have shown that oxidative stress is associated with the pathogenesis of ZIKV infection in vitro and in vivo, and that silymarin has anti-ZIKV action in vitro. Here, we characterised the antioxidant and antiviral effects of silymarin against ZIKV infection in an animal model. We observed an increase in the levels of biomarkers of oxidative damage and in antioxidant enzyme activities in the livers of ZIKV-infected C57BL/6 mice. However, these effects were reversed in ZIKV-infected animals that were treated with silymarin. Furthermore, silymarin reduced the viral load in the livers of animals. Next, by in vitro studies, we confirmed that the anti-ZIKV action of silymarin is independent of its antioxidant activity. This work reinforces the potential use of silymarin against Zika fever.

Robust antiviral innate immune response and miRNA regulatory network were identified in ZIKV-infected cells: implications in the pathogenesis of ZIKV infection

Zika virus (ZIKV) infection has emerged as a significant public health concern due to its association with fetal microcephaly and Guillain-Barre syndrome (GBS). Unfortunately, its detailed pathogenesis remains unclear. To better understand how ZIKV evades host antiviral immunity, we analyzed the microarray dataset (GSE98889) of ZIKV-infected primary human brain microvascular endothelial cells (hBMECs) retrieved from the gene expression omnibus (GEO). 160, 1423, 969, 829, and 600 differentially expressed genes (DEGs) were identified at 12, 24, 48, 72, and 216 hours post-ZIKV infection in hBMECs, respectively. Subsequently, 31 common DEGs across all time-points were selected for further analysis. Gene ontology (GO) functional analysis showed these 31 DEGs were mainly involved in the host antiviral innate immune responses. Protein-protein interaction (PPI) network analysis identified 10 hub genes (MX1, OAS1, OAS2, IFI44, IFI44L, IFIT1, IFIT2, IFIT3, IFIH1, and XAF1), which were all interferon-stimulated genes (ISGs) and upregulated. qRT-PCR was used to validate the expression patterns of these 10 hub genes in different ZIKV-infected cell lines. Finally, miRNA-mRNA regulatory network analysis revealed that hsa-miR-129-2-3p, hsa-miR-138-5p, hsa-miR-21-3p, hsa-miR-27a-5p, hsa-miR-449a, and hsa-miR449b-5p were key miRNAs regulating these hub genes. Our study showed that ZIKV infection activated the host innate immune response to restrict ZIKV infection. The common pathways, hub genes, and their regulatory miRNA network offer new insights into virus-host interactions, enhancing our understanding of ZIKV pathogenesis.

Arboviruses: the hidden danger of the tropics

Arboviruses are viruses that are transmitted by arthropods such as mosquitoes, ticks, and flies, and most of them are RNA viruses. Vector-borne transmission occurs when an infected arthropod bites a vertebrate host, allowing the virus to enter the bloodstream and initiate infection. Arboviruses are known to cause significant morbidity and mortality in mammals, and at least a hundred of them have been identified as human pathogens. In this review, we provide an updated overview of four prominent arboviruses that are present in Southeast Asia (SEA): dengue virus (DENV), Japanese encephalitis virus (JEV), Zika virus (ZIKV), and chikungunya virus (CHIKV). The epidemiology and pathogenesis of these viruses and the currently used methods for diagnosis, prevention, and treatment of arbovirus infections are discussed in detail. Finally, we summarise the concerns and future considerations for combating these dangerous pathogens.

A brief overview of the E3 ubiquitin ligase: TRIM7

TRIM7, a member of the E3 ubiquitin ligase family, has garnered significant attentions in different research fields since its discovery. This enzyme plays indispensable roles in various pathophysiological processes through ubiquitination-mediated degradation of diverse protein substrates. This review systematically summarizes the current knowledge on the protein structure and biological functions of TRIM7. Structurally, TRIM7 features a conserved RBCC motif (RING, B-box, and coiled-coil domains) coupled with a variable C-terminal region that dictates the substrate specificity. In infectious contexts, TRIM7 is required for the pathogen-specific regulation, and exerts paradoxical effects by either promoting host defense or facilitating viral pathogenesis depending on pathogen type. Within oncology, TRIM7 manifests tumor-suppressive properties through regulating metastasis, apoptosis, and tumor immunology. In addition, it might serve as a reliable biomarker for monitoring the progression of idiopathic pulmonary fibrosis and also inhibits the progression of atherosclerosis. In summary, TRIM7 plays critical roles in different pathophysiological processes, and it might be a predictive and therapeutic target in certain human diseases.

Mothers and mosquitoes: climate change contributes to the spread of vector-borne pathogens posing a substantial threat to pregnant women

Infectious diseases have threatened individuals and societies since the dawn of humanity. Certain population groups, including pregnant women, young children and the elderly, are particularly vulnerable to severe infections. Over the past few centuries, advances in medical standards and the availability of vaccines have reduced infection-related mortality and morbidity rates in industrialized countries. However, the global rise in temperatures and increased precipitation present a new challenge, facilitating the broader distribution of disease vectors, such as mosquitoes, bugs and ticks, to higher altitudes and latitudes. Consequently, epidemic and pandemic outbreaks associated with these vectors, such as Zika, West Nile, dengue, yellow fever, chikungunya and malaria, are increasingly impacting diverse populations. This review comprehensively examines how infections associated with climate change disproportionately affect the health and well-being of pregnant women and their unborn children. There has been a noticeable emergence of vector-borne diseases in Europe. Consequently, we stress the importance of implementing measures that effectively protect pregnant women from these increasing infections globally and regionally. We advocate for initiatives to safeguard pregnant women from these emerging threats, beginning with enhanced education to raise awareness about the evolving risks this particularly vulnerable population faces.

The HAVCR1-centric host factor network drives Zika virus vertical transmission

Zika virus (ZIKV) vertical transmission results in devastating congenital malformations and pregnancy complications; however, the specific receptor and host factors facilitating ZIKV maternal-fetal transmission remain elusive. Here, we employ a genome-wide CRISPR screening and identify multiple placenta-intrinsic factors modulating ZIKV infection. Our study unveils that hepatitis A virus cellular receptor 1 (HAVCR1) serves as a primary receptor governing ZIKV entry in placental trophoblasts. The GATA3-HAVCR1 axis regulates heterogeneous cell tropism in the placenta. Notably, placenta-specific Havcr1 deletion in mice significantly impairs ZIKV transplacental transmission and associated adverse pregnancy outcomes. Mechanistically, the immunoglobulin variable-like domain of HAVCR1 binds to ZIKV via domain III of envelope protein and virion-associated phosphatidylserine. Proteomic profiling and function analyses reveal that AP2S1 cooperates with HAVCR1 for ZIKV internalization through clathrin-mediated endocytosis. Overall, our work underscores the pivotal role of HAVCR1 in mediating ZIKV vertical transmission and highlights a therapeutic target for alleviating congenital Zika syndrome.

Zika virus transmission in Aedes aegypti: A systematic study on the ability of mosquitoes to transmit the virus horizontally and vertically

Zika virus (ZIKV) is a mosquito-borne virus belonging to the genus Orthoflavivirus, and the family Flaviviridae. It commonly presents with febrile-like symptoms, neurological issues, and pregnancy complications in humans. Currently, there is no commercial vaccine or specific treatment available to prevent ZIKV infection. Therefore, controlling the epidemic's spread relies on preventing mosquitoes from transmitting the virus. Although various studies have explored the transmission of ZIKV between mosquitoes and vertebrate hosts, comprehensive research on potential mosquito-to-mosquito transmission of ZIKV remains limited. In this study, we conducted systematic laboratory investigations to assess the ability of ZIKV to spread among mosquitoes, and to evaluate the impact of ZIKV infection on mosquito development. Our findings revealed that ZIKV can be transmitted between Aedes aegypti mosquitoes both vertically and horizontally, through oviposition and contact between mosquitoes of the same or opposite sex. Additionally, we observed that ZIKV infection resulted in a reduction in the number of mosquito eggs but an increase in their size. The widespread distribution of ZIKV in infected mosquitoes and the altered levels of hormone related genes following viral infection were noted, which may contribute to viral transmission among mosquitoes and affect mosquito development. This research provides systematic experimental evidence of ZIKV transmission among mosquitoes, which is crucial for developing novel strategies to disrupt the spread of orthoflaviviruses and other mosquito-borne pathogens.

Vaccines Against Urban Epidemic Arboviruses: The State of the Art

Arboviruses represent a contemporary global challenge, prompting coordinated efforts from health organizations and governments worldwide. Dengue, chikungunya, and Zika viruses have become endemic in the tropics, resulting in the so-called "triple arbovirus epidemic". These viruses are transmitted typically through the bites of infected mosquitoes, especially A. aegypti and A. albopictus. These mosquito species are distributed across all continents and exhibit a high adaptive capacity in diverse environments. When combined with unplanned urbanization, uncontrolled population growth, and international travel-the so-called "triad of the modern world"-the maintenance and spread of these pathogens to new areas are favored. This review provides updated information on vaccine candidates targeting dengue, chikungunya, and Zika viruses. Additionally, we discuss the challenges, perspectives, and issues associated with their successful production, testing, and deployment within the context of public health.

Neurological Manifestations of Zika Virus Infection: An Updated Review of the Existing Literature

Zika virus (ZIKV) is a neurotropic virus closely linked to other flaviviruses like dengue virus, West Nile virus, yellow fever, and Japanese encephalitis virus. Though initially considered a mild virus, ZIKV gained everybody's attention when the World Health Organization (WHO) declared it a global public health emergency in February 2016. Being considered an important cause of innumerable neurological manifestations and pediatric modality, we aimed to present a comprehensive overview of the neurological details of ZIKV infection. This study reviews the neurological manifestations of ZIKV infection. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) strategy was employed, along with a combination of keywords, to enlist all articles with data on ZIKV and its neurological manifestations, diagnosis, and treatment. All case reports, case series, and systematic reviews published between 2017 and 2024, focusing on neurological manifestations of ZIKV, were included in this study. Case studies, editorials, letters to the editors, and clinical images were excluded. The search was conducted using Boolean operators "AND" and "OR" on PubMed and Google Scholar. A total of five case reports, one case series, and one systematic review and meta-analysis were included. Out of 603 patients, the study suggested a male preponderance of 366 patients (62.5%) for ZIKV infection. About 258 patients presented with rash (46.1%), 243 with fever (43.8%), and 134 with dysphagia (36.5%). Neurological signs on examination were limb paresis in 545 (91.1%) patients, areflexia in 401 (88.9%) patients, and tetraparesis in 153 (61%) patients. A significant finding on magnetic resonance imaging (MRI) showed enhancement of the distal cord, conus medullaris, and cauda equina in two cases (0.3%). Serological analysis showed a positive plaque reduction neutralization test (PRNT) in 125 (73.5%) patients. Increased protein levels were identified in 240 (78.7%) cases on cerebrospinal fluid (CSF) analysis. The commonest diagnostic modality utilized was polymerase chain reaction (PCR) in 118 (24.3%) cases. Intravenous immunoglobulins (IVIg) were used for the medical management of 442 patients included in this review (77.4%). ZIKV is known to cause insidious detrimental effects on the central nervous system regardless of the age of an individual. Being a cause of extreme sensorimotor disability, various preventive and precautionary measures are being undertaken to ensure early diagnosis and prevent prolonged liability on a patient's health. Effective therapeutics including IVIg have paved the way in bringing down the hurdles in the management and cure of the infection.

Intrauterine Zika Virus Infection: An Overview of the Current Findings

Zika virus (ZIKV) is a mosquito-borne flavivirus of the family Flaviviridae. The association between ZIKV and microcephaly was first described in Brazil in 2015. The risk of vertical transmission occurs in pregnant women with or without symptoms, and the risk of malformation appears to be worse when infection occurs in the first and second trimesters of pregnancy. The rate of vertical transmission varies from 26 to 65%, and not all fetuses develop malformations. The incidence of malformations resulting from transmission is uncertain, ranging from 6-8% in the US to 40% in Brazil. Congenital ZIKV syndrome is a set of clinical manifestations that can affect the fetus of a mother infected with ZIKV. The manifestations are broad and nonspecific, including microcephaly, subcortical calcifications, ocular changes, congenital contractures, early hypertension, and pyramidal and extrapyramidal signs. Other findings such as growth restriction and fetal miscarriage/death may also occur. Our aim in this article is to review the literature on mosquito transmission, clinical presentation, serologic diagnosis, intrauterine transmission, pre- and postnatal imaging diagnostic findings, and short- and long-term follow-up.

Zika virus: advancing a priority research agenda for preparedness and response

The 2015-16 Zika virus epidemic emerged in the Americas and rapidly spread throughout the region and beyond, showing the epidemic potential of this mosquito-borne Orthoflavivirus and its capacity to cause severe congenital malformations and neurological sequelae. WHO declared the Zika virus epidemic a public health emergency of international concern in 2016. Despite this declaration, there are no licensed Zika virus vaccines, therapeutics, or diagnostic tests appropriate for routine antenatal screening. To address this absence of essential tools to detect and mitigate the threat of future Zika virus outbreaks, a group of global experts developed a priority agenda for Zika virus research and development. This Series paper summarises crucial challenges and knowledge gaps and outlines a comprehensive strategy to advance research, surveillance, global capacity, policy, and investment for Zika virus preparedness and response.

Advancements in Viral Genomics: Gated Recurrent Unit Modeling of SARS-CoV-2, SARS, MERS, and Ebola viruses

BACKGROUND

Emerging infections have posed persistent threats to humanity throughout history. Rapid and unprecedented anthropogenic, behavioral, and social transformations witnessed in the past century have expedited the emergence of novel pathogens, intensifying their impact on the global human population.

METHODS

This study aimed to comprehensively analyze and compare the genomic sequences of four distinct viruses: SARS-CoV-2, SARS, MERS, and Ebola. Advanced genomic sequencing techniques and a Gated Recurrent Unit-based deep learning model were used to examine the intricate genetic makeup of these viruses. The proposed study sheds light on their evolutionary dynamics, transmission patterns, and pathogenicity and contributes to the development of effective diagnostic and therapeutic interventions.

RESULTS

This model exhibited exceptional performance as evidenced by accuracy values of 99.01%, 98.91%, 98.35%, and 98.04% for SARS-CoV-2, SARS, MERS, and Ebola respectively. Precision values ranged from 98.1% to 98.72%, recall values consistently surpassed 92%, and F1 scores ranged from 95.47% to 96.37%.

CONCLUSIONS

These results underscore the robustness of this model and its potential utility in genomic analysis, paving the way for enhanced understanding, preparedness, and response to emerging viral threats. In the future, this research will focus on creating better diagnostic instruments for the early identification of viral illnesses, developing vaccinations, and tailoring treatments based on the genetic composition and evolutionary patterns of different viruses. This model can be modified to examine a more extensive variety of diseases and recently discovered viruses to predict future outbreaks and their effects on global health.

Microcephaly protein ANKLE2 promotes Zika virus replication

Orthoflaviviruses are positive-sense single-stranded RNA viruses that hijack host proteins to promote their own replication. Zika virus (ZIKV) is infamous among orthoflaviviruses for its association with severe congenital birth defects, notably microcephaly. We previously mapped ZIKV-host protein interactions and identified the interaction between ZIKV non-structural protein 4A (NS4A) and host microcephaly protein ankyrin repeat and LEM domain-containing 2 (ANKLE2). Using a fruit fly model, we showed that NS4A induced microcephaly in an ANKLE2-dependent manner. Here, we explore the role of ANKLE2 in ZIKV replication to understand the biological significance of the interaction from a viral perspective. We observe that ANKLE2 localization is drastically shifted to sites of NS4A accumulation during infection and that knockout of ANKLE2 reduces ZIKV replication in multiple human cell lines. This decrease in virus replication is coupled with a moderate increase in innate immune activation. Using microscopy, we observe dysregulated formation of virus-induced endoplasmic reticulum rearrangements in ANKLE2 knockout cells. Knockdown of the ANKLE2 ortholog in Aedes aegypti cells also decreases virus replication, suggesting ANKLE2 is a beneficial replication factor across hosts. Finally, we show that NS4A from four other orthoflaviviruses physically interacts with ANKLE2 and is also beneficial to their replication. Thus, ANKLE2 likely promotes orthoflavivirus replication by regulating membrane rearrangements that serve to accelerate viral genome replication and protect viral dsRNA from immune detection. Taken together with our previous results, our findings indicate that ZIKV and other orthoflaviviruses hijack ANKLE2 for a conserved role in replication, and this drives unique pathogenesis for ZIKV since ANKLE2 has essential roles in developing tissues.IMPORTANCEZIKV is a major concern due to its association with birth defects, including microcephaly. We previously identified a physical interaction between ZIKV NS4A and host microcephaly protein ANKLE2. Mutations in ANKLE2 cause congenital microcephaly, and NS4A induces microcephaly in an ANKLE2-dependent manner. Here, we establish the role of ANKLE2 in ZIKV replication. Depletion of ANKLE2 from cells significantly reduces ZIKV replication and disrupts virus-induced membrane rearrangements. ANKLE2's ability to promote ZIKV replication is conserved in mosquito cells and for other related mosquito-borne orthoflaviviruses. Our data point to an overall model in which ANKLE2 regulates virus-induced membrane rearrangements to accelerate orthoflavivirus replication and avoid immune detection. However, ANKLE2's unique role in ZIKV NS4A-induced microcephaly is a consequence of ZIKV infection of important developing tissues in which ANKLE2 has essential roles.

Inactivation of Zika Virus with Hydroxypropyl-Beta-Cyclodextrin

Background/Objectives: Zika virus (ZIKV) infection is associated with life-threatening diseases in humans. To date, there are no available FDA-approved therapies or vaccines for the specific treatment or prevention of ZIKV infection. Variation in the ZIKV envelope protein (Env), along with its complex quaternary structure, presents challenges to synthetic approaches for developing an effective vaccine and broadly neutralizing antibodies (bnAbs). We hypothesized that beta-cyclodextrin (BCD) could be used to uniquely inactivate infectious ZIKV without disruption of Env. Methods: ZIKV was propagated in Vero cells and admixed with BCD. The BCD-treated ZIKV was evaluated for infectivity using immunofluorescence and quantitative RT-PCR (qRT-PCR) assays, for immunoreactivity in Western blots, structural integrity by electron microscopy, and immunogenicity in mice. Results: Here, we show that 200 mM BCD-treated ZIKV is non-infectious in cell culture, remains immunoreactive with an Env-specific antibody, retains its virion shape and size, and elicits the production of immunogen-specific antibodies in immunized mice. Conclusions: These results indicate that BCD can be used to safely inactivate ZIKV, and they provide insights for vaccine and antibody development.

Comparison of Three Chimeric Zika Vaccine Prototypes Developed on the Genetic Background of the Clinically Proven Live-Attenuated Japanese Encephalitis Vaccine SA14-14-2

Zika virus (ZIKV) is a medically important mosquito-borne orthoflavivirus, but no vaccines are currently available to prevent ZIKV-associated disease. In this study, we compared three recombinant chimeric viruses developed as candidate vaccine prototypes (rJEV/ZIKVMR-766, rJEV/ZIKVP6-740, and rJEV/ZIKVPRVABC-59), in which the two neutralizing antibody-inducing prM and E genes from each of three genetically distinct ZIKV strains were used to replace the corresponding genes of the clinically proven live-attenuated Japanese encephalitis virus vaccine SA14-14-2 (rJEV). In WHO-certified Vero cells (a cell line suitable for vaccine production), rJEV/ZIKVP6-740 exhibited the slowest viral growth, formed the smallest plaques, and displayed a unique protein expression profile with the highest ratio of prM to cleaved M when compared to the other two chimeric viruses, rJEV/ZIKVMR-766 and rJEV/ZIKVPRVABC-59, as well as their vector, rJEV. In IFNAR-/- mice, an animal model of ZIKV infection, subcutaneous inoculation of rJEV/ZIKVP6-740 caused a low-level localized infection limited to the spleen, with no clinical signs of infection, weight loss, or mortality; in contrast, the other two chimeric viruses and their vector caused high-level systemic infections involving multiple organs, consistently leading to clear clinical signs of infection, rapid weight loss, and 100% mortality. Subsequently, subcutaneous immunization with rJEV/ZIKVP6-740 proved highly effective, offering complete protection against a lethal intramuscular ZIKV challenge 28 days after a single-dose immunization. This protection was specific to ZIKV prM/E and likely mediated by neutralizing antibodies targeting ZIKV prM/E. Therefore, our data indicate that the chimeric virus rJEV/ZIKVP6-740 is a highly promising vaccine prototype for developing a safe and effective vaccine for inducing neutralizing antibody-mediated protective immunity against ZIKV.

The Dual Resistance Mechanism of CYP325G4 and CYP6AA9 in Culex pipiens pallens Legs According to Transcriptome and Proteome Analysis

Mosquitoes within the Culex pipiens complex play a crucial role in human disease transmission. Insecticides, especially pyrethroids, are used to control these vectors. Mosquito legs are the main entry point and barrier for insecticides to gain their neuronal targets. However, the resistance mechanism in mosquito legs is unclear. Herein, we employed transcriptomic analyses and isobaric tags for relative and absolute quantitation techniques to investigate the resistance mechanism, focusing on Cx. pipiens legs. We discovered 2346 differentially expressed genes (DEGs) between deltamethrin-resistant (DR) and deltamethrin-sensitive (DS) mosquito legs, including 41 cytochrome P450 genes. In the same comparison, we identified 228 differentially expressed proteins (DEPs), including six cytochrome P450 proteins. Combined transcriptome and proteome analysis revealed only two upregulated P450 genes, CYP325G4 and CYP6AA9. The main clusters of DEGs and DEPs were associated with metabolic processes, such as cytochrome P450-mediated metabolism of drugs and xenobiotics. Transcription analysis revealed high CYP325G4 and CYP6AA9 expression in the DR strain at 72 h posteclosion compared with that in the DS strain, particularly in the legs. Mosquitoes knocked down for CYP325G4 were more sensitive to deltamethrin than the controls. CYP325G4 knockdown reduced the expression of several chlorinated hydrocarbon (CHC)-related genes, which altered the cuticle thickness and structure. Conversely, CYP6AA9 knockdown increased CHC gene expression without altering cuticle thickness and structure. P450 activity analysis demonstrated that CYP325G4 and CYP6AA9 contributed to metabolic resistance in the midgut and legs. This study identified CYP325G4 as a novel mosquito deltamethrin resistance factor, being involved in both metabolic and cuticular resistance mechanisms. The previously identified CYP6AA9 was investigated for its involvement in metabolic resistance and potential cuticular resistance in mosquito legs. These findings enhance our comprehension of resistance mechanisms, identifying P450s as promising targets for the future management of mosquito vector resistance, and laying a theoretical groundwork for mosquito resistance management.

Six new prenylated flavonoids from Dodonaea viscosa with anti-Zika virus activity

Six new prenylated flavonoids, named visconaeas A-F (1-6), and eleven known isopentenyl flavonoids (7-17) were isolated from Dodonaea viscosa (L.) Jacq. The structures of the separated compounds were determined through comprehensive spectral analysis and quantum chemical calculations. These compounds were tested for their anti-Zika virus and cytotoxicity activities. The results indicated that compound 4 showed low cytotoxicity and strong anti-Zika virus potential with EC50 16.34 μM.

Long non-coding RNA SUN2-AS1 acts as a negative regulator of ISGs transcription to promote flavivirus infection

Recent studies highlight the critical involvement of long non-coding RNAs (lncRNAs) in modulating viral replication and immune responses, yet their specific roles in flavivirus infections remain underexplored. Our study has identified lncRNA SUN2-AS1, which is significantly upregulated in response to flavivirus infection in A549, Huh7 cells, and monocyte-differentiated macrophages (MDMs). SUN2-AS1 interacts with the transcription factors NF-κB and STAT1, andits expression is induced by ZIKV RNA via the type I interferon (IFN) pathway. Notably, SUN2-AS1 enhances the infection of flaviviruses, including ZIKV, DENV2, and JEV, while showing no effect on VSV or HSV-1 infections. Mechanistically, SUN2-AS1 exerts a proviral effect by inhibiting the transcription of interferon-stimulated genes (ISGs). These findings uncover a novel mechanism by which lncRNAs facilitate flavivirus propagation and highlight SUN2-AS1 as a potential target for antiviral therapeutic strategies.

The fate of neuronal synapse homeostasis in aging, infection, and inflammation

Neuroplasticity is the brain's ability to reorganize and modify its neuronal connections in response to environmental stimuli, experiences, learning, and disease processes. This encompasses a variety of mechanisms, including changes in synaptic strength and connectivity, the formation of new synapses, alterations in neuronal structure and function, and the generation of new neurons. Proper functioning of synapses, which facilitate neuron-to-neuron communication, is crucial for brain activity. Neuronal synapse homeostasis, which involves regulating and maintaining synaptic strength and function in the central nervous system (CNS), is vital for this process. Disruptions in synaptic balance, due to factors like inflammation, aging, or infection, can lead to impaired brain function. This review highlights the main aspects and mechanisms underlying synaptic homeostasis, particularly in the context of aging, infection, and inflammation.

AMFR-mediated Flavivirus NS2A ubiquitination subverts ER-phagy to augment viral pathogenicity

Flaviviruses strategically utilize the endoplasmic reticulum (ER) in their replication cycles. However, the role of ER autophagy (ER-phagy) in viral replication process remains poorly understood. Here, we reveal that prolonged Zika virus (ZIKV) infection results from the degradation of ER-phagy receptor FAM134B, facilitated by viral NS2A protein. Mechanistically, ER-localized NS2A undergoes K48-linked polyubiquitination at lysine (K) 56 by E3 ligase AMFR. Ubiquitinated NS2A binds to FAM134B and AMFR orchestrates the degradation of NS2A-FAM134B complexes. AMFR-catalyzed NS2A ubiquitination not only targets FAM134B degradation but also hinders the FAM134B-AMFR axis. Notably, a recombinant ZIKV mutant (ZIKV-NS2AK56R), lacking ubiquitination and ER-phagy inhibition, exhibits attenuation in ZIKV-induced microcephalic phenotypes in human brain organoids and replicates less efficiently, resulting in weakened pathogenesis in mouse models. In this work, our mechanistic insights propose that flaviviruses manipulate ER-phagy to modulate ER turnover, driving viral infection. Furthermore, AMFR-mediated flavivirus NS2A ubiquitination emerges as a potential determinant of viral pathogenecity.

Balancing acts: The posttranslational modification tightrope of flavivirus replication

Posttranslational modifications (PTMs) such as phosphorylation, ubiquitination, SUMOylation, and ISGylation are involved in various cellular pathways, including innate immunity and disease processes. Many viruses have developed sophisticated mechanisms to modulate these host PTMs, either by inhibiting the interferon pathway or by enhancing the stability and function of viral proteins essential for replication. In this Pearl, we review the literature on how flaviviruses are impacted by and exploit posttranslational modifications to their advantage.

Emerging and reemerging infectious diseases: global trends and new strategies for their prevention and control

To adequately prepare for potential hazards caused by emerging and reemerging infectious diseases, the WHO has issued a list of high-priority pathogens that are likely to cause future outbreaks and for which research and development (R&D) efforts are dedicated, known as paramount R&D blueprints. Within R&D efforts, the goal is to obtain effective prophylactic and therapeutic approaches, which depends on a comprehensive knowledge of the etiology, epidemiology, and pathogenesis of these diseases. In this process, the accessibility of animal models is a priority bottleneck because it plays a key role in bridging the gap between in-depth understanding and control efforts for infectious diseases. Here, we reviewed preclinical animal models for high priority disease in terms of their ability to simulate human infections, including both natural susceptibility models, artificially engineered models, and surrogate models. In addition, we have thoroughly reviewed the current landscape of vaccines, antibodies, and small molecule drugs, particularly hopeful candidates in the advanced stages of these infectious diseases. More importantly, focusing on global trends and novel technologies, several aspects of the prevention and control of infectious disease were discussed in detail, including but not limited to gaps in currently available animal models and medical responses, better immune correlates of protection established in animal models and humans, further understanding of disease mechanisms, and the role of artificial intelligence in guiding or supplementing the development of animal models, vaccines, and drugs. Overall, this review described pioneering approaches and sophisticated techniques involved in the study of the epidemiology, pathogenesis, prevention, and clinical theatment of WHO high-priority pathogens and proposed potential directions. Technological advances in these aspects would consolidate the line of defense, thus ensuring a timely response to WHO high priority pathogens.

The inoculum dose of Zika virus can affect the viral replication dynamics, cytokine responses and survival rate in immunocompromised AG129 mice

Zika virus, a mosquito-borne arbovirus, has repeatedly caused large pandemics with symptoms worsening from mild and self-limiting diseases to Guillain-Barré syndrome in adults and fetal microcephaly in newborns. In recent years, Zika virus diseases have posed a serious threat to human health. The shortage of susceptible small animal models makes it difficult to study pathogenic mechanisms and evaluate potential therapies for Zika virus infection. Therefore, we chose immunocompromised mice (AG129 mice) deficient in IFN-α/β and IFN-γ receptors, which can abolish the innate immune system that prevents Zika virus infection early. AG129 mice were infected with the Zika virus, and this mouse model exhibited replication dynamics, tissue tropism, pathological lesion and immune activation of the Zika virus. Our results suggest that the inoculum dose of Zika virus can affect the viral replication dynamics, cytokine responses and survival rate in AG129 mice. By testing the potential antiviral drug favipiravir, several critical indicators, including replication dynamics and survival rates, were identified in AG129 mice after Zika virus infection. It is suggested that the model is reliable for drug evaluation. In brief, this model provides a potential platform for studies of the infectivity, virulence, and pathogenesis of the Zika virus. Moreover, the development of an accessible mouse model of Zika virus infection will expedite the research and deployment of therapeutics and vaccines.

The NS1 protein of contemporary West African Zika virus potentiates viral replication and reduces innate immune activation

Mosquito-borne Zika virus (ZIKV) from sub-Saharan Africa has recently gained attention due to its epidemic potential and its capacity to be highly teratogenic. To improve our knowledge on currently circulating strains of African ZIKV, we conducted protein sequence alignment and identified contemporary West Africa NS1 (NS1CWA) protein as a highly conserved viral protein. Comparison of NS1CWA with the NS1 of the historical African ZIKV strain MR766 (NS1MR766), revealed seven amino acid substitutions. The effects of NS1 mutations on protein expression, virus replication, and innate immune activation were assessed in human cells using recombinant NS1 proteins and a chimeric viral clone MR766 with NS1CWA replacing NS1MR766. Our data indicated higher secretion efficiency of NS1CWA compared to NS1MR766 associated with a change in subcellular distribution. A chimeric MR766 virus with NS1CWA instead of authentic protein displayed a greater viral replication efficiency, leading to more pronounced cell death compared to parental virus. Enhanced viral growth was associated with reduced activation of innate immunity. Our data raise questions of the importance of NS1 protein in the pathogenicity of contemporary ZIKV from sub-Saharan Africa and point to differences within viral strains of African lineage.

Targeting glucose metabolism with dichloroacetate (DCA) reduces zika virus replication in brain cortical progenitors at different stages of maturation

The underlying threat of new Zika virus (ZIKV) outbreaks remains, as no vaccines or therapies have yet been developed. In vitro research has shown that glycolysis is a key factor to enable sustained ZIKV replication in neuroprogenitors. However, neither in vivo nor clinical investigation of glycolytic modulators as potential therapeutics for ZIKV-related fetal abnormalities has been conducted. Accordingly, we tested the therapeutic potential of metabolic modulators in relevant in vitro systems comprising two pools of neuroprogenitors (NPCs), which resemble early and late stages of pregnancy. Effective doses of metabolic modulators [3.0 μM] dimethyl fumarate (DMF), [3.2 mM] dichloroacetate (DCA), and [6.3 μM] VER-246608 were determined for these cells by their effect on lactate release, pyruvate dehydrogenase (PDH) activity and cell survival. The drugs were used in a 24h pre-treatment and kept throughout ZIKV infection of NPCs. Drug effects and ZIKV replication were assessed at 24- and 56-h post-infection. In early NPCs treated with DMF, DCA and VER-246608, there was a significant reduction in the extracellular release of ZIKV potentially by PDH-mediated increased mitochondrial oxidation of glucose. Out of the three drugs, only DCA was observed to reduce viral replication in late NPCs treated with DCA. Altogether, our findings suggest that reduction of anaerobic glycolysis could be of therapeutic potential against ZIKV-related fetal abnormalities and that clinical translation should consider the use of specific glycolytic modulators over different trimesters.

Immunogenicity and safety of a self-assembling ZIKV nanoparticle vaccine in mice

Zika virus (ZIKV) is a mosquito-borne flavivirus that highly susceptibly causes Guillain-Barré syndrome and microcephaly in newborns. Vaccination is one of the most effective measures for preventing infectious diseases. However, there is currently no approved vaccine to prevent ZIKV infection. Here, we developed nanoparticle (NP) vaccines by covalently conjugating self-assembled 24-subunit ferritin to the envelope structural protein subunit of ZIKV to achieve antigen polyaggregation. The immunogenicityof the NP vaccine was evaluated in mice. Compared to monomer vaccines, the NP vaccine achieved effective antigen presentation, promoted the differentiation of follicular T helper cells in lymph nodes, and induced significantly greater antigen-specific humoral and cellular immune responses. Moreover, the NP vaccine enhanced high-affinity antigen-specific IgG antibody levels, increased secretion of the cytokines IL-4 and IFN-γ by splenocytes, significantly activated T/B lymphocytes, and improved the generation of memory T/B cells. In addition, no significant adverse reactions occurred when NP vaccine was combined with adjuvants. Overall, ferritin-based NP vaccines are safe and effective ZIKV vaccine candidates.

A novel vaccine construct against Zika virus fever: insights from epitope-based vaccine discovery through molecular modeling and immunoinformatics approaches

The Zika virus (ZIKV) is an emerging virus associated with the Flaviviridae family that mainly causes infection in pregnant women and leads to several abnormalities during pregnancy. This virus has unique properties that may lead to pathological diseases. As the virus has the ability to evade immune response, a crucial effort is required to deal with ZIKV. Vaccines are a safe means to control different pathogenic infectious diseases. In the current research, a multi-epitope-based vaccination against ZIKV is being designed using in silico methods. For the epitope prediction and prioritization phase, ZIKV polyprotein (YP_002790881.1) and flavivirus polyprotein (>YP_009428568.1) were targeted. The predicted B-cell epitopes were used for MHC-I and MHC-II epitope prediction. Afterward, several immunoinformatics filters were applied and nine (REDLWCGSL, MQDLWLLRR, YKKSGITEV, TYTDRRWCF, RDAFPDSNS, KPSLGLINR, ELIGRARVS, AITQGKREE, and EARRSRRAV) epitopes were found to be probably antigenic in nature, non-allergenic, non-toxic, and water soluble without any toxins. Selected epitopes were joined using a particular GPGPG linker to create the base vaccination for epitopes, and an extra EAAAK linker was used to link the adjuvant. A total of 312 amino acids with a molecular weight (MW) of 31.62762 and an instability value of 34.06 were computed in the physicochemical characteristic analysis, indicating that the vaccine design is stable. The molecular docking analysis predicted a binding energy of -329.46 (kcal/mol) for TLR-3 and -358.54 (kcal/mol) for TLR-2. Moreover, the molecular dynamics simulation analysis predicted that the vaccine and receptor molecules have stable binding interactions in a dynamic environment. The C-immune simulation analysis predicted that the vaccine has the ability to generate both humoral and cellular immune responses. Based on the design, the vaccine construct has the best efficacy to evoke immune response in theory, but experimental analysis is required to validate the in silico base approach and ensure its safety.

Common arboviruses and the kidney: a review

Arboviruses are endemic in several countries and represent a worrying public health problem. The most important of these diseases is dengue fever, whose numbers continue to rise and have reached millions of annual cases in Brazil since the last decade. Other arboviruses of public health concern are chikungunya and Zika, both of which have caused recent epidemics, and yellow fever, which has also caused epidemic outbreaks in our country. Like most infectious diseases, arboviruses have the potential to affect the kidneys through several mechanisms. These include the direct action of the viruses, systemic inflammation, hemorrhagic phenomena and other complications, in addition to the toxicity of the drugs used in treatment. In this review article, the epidemiological aspects of the main arboviruses in Brazil and other countries where these diseases are endemic, clinical aspects and the main laboratory changes found, including changes in renal function, are addressed. It also describes how arboviruses behave in kidney transplant patients. The pathophysiological mechanisms of kidney injury associated with arboviruses are described and finally the recommended treatment for each disease and recommendations for kidney support in this context are given.

Atranorin inhibits Zika virus infection in human glioblastoma cell line SNB-19 via targeting Zika virus envelope protein

BACKGROUND

Zika virus (ZIKV) is a single-stranded RNA flavivirus transmitted by mosquitoes. Its infection is associated with neurological complications such as neonatal microcephaly and adult Guillain-Barré syndrome, posing a serious threat to the health of people worldwide. Therefore, there is an urgent need to develop effective anti-ZIKV drugs. Atranorin is a lichen secondary metabolite with a wide range of biological activities, including anti-inflammatory, antibacterial and antioxidant, etc. However, the antiviral activity of atranorin and underlying mechanism has not been fully elucidated.

PURPOSE

We aimed to determine the anti-ZIKV activity of atranorin in human glioma cell line SNB-19 and investigate the potential mechanism from the perspective of viral life cycle and the host cell functions.

METHODS

We first established ZIKV-infected human glioma cells (SNB-19) model and used Western Blot, RT-qPCR, immunofluorescence, fluorescence-activated cell sorting (FACS) and plaque assay to evaluate the anti-ZIKV activity of atranorin. Then we assessed the regulation effect of atranorin on ZIKV induced IFN signal pathway activation by RT-qPCR. Afterward, we introduced time-of-addition assay, viral adsorption assay, viral internalization assay and transferrin uptake assay to define which step of ZIKV lifecycle is influenced by atranorin. Finally, we performed virus infectivity assay, molecular docking and thermal shift assay to uncover the target protein of atranorin on ZIKV.

RESULTS

Our study showed that atranorin could protect SNB-19 cells from ZIKV infection, as evidenced by inhibited viral protein expression and progeny virus yield. Meanwhile, atranorin attenuated the activation of IFN signal pathway and downstream inflammatory response that induced by ZIKV infection. The results of time-of-addition assay indicated that atranorin acted primarily by disturbing the viral entry process. After ruling out the effect of atranorin on AXL receptor tyrosine kinase (AXL) dependent virus adsorption and clathrin-mediated endocytosis, we confirmed that atranorin directly targeted the viral envelope protein and lowered ZIKV infectivity by thermal shift assay and virus infectivity assay respectively.

CONCLUSION

We found atranorin inhibits ZIKV infection in SNB-19 cells via targeting ZIKV envelope protein. Our study provided an experimental basis for the further development of atranorin and a reference for antiviral drug discovery from natural resources.

Transduction Efficiency of Zika Virus E Protein Pseudotyped HIV-1gfp and Its Oncolytic Activity Tested in Primary Glioblastoma Cell Cultures

The development of new tools against glioblastoma multiforme (GBM), the most aggressive and common cancer originating in the brain, remains of utmost importance. Lentiviral vectors (LVs) are among the tools of future concepts, and pseudotyping offers the possibility of tailoring LVs to efficiently transduce and inactivate GBM tumor cells. Zika virus (ZIKV) has a specificity for GBM cells, leaving healthy brain cells unharmed, which makes it a prime candidate for the development of LVs with a ZIKV coat. Here, primary GBM cell cultures were transduced with different LVs encased with ZIKV envelope variants. LVs were generated by using the pNLgfpAM plasmid, which produces the lentiviral, HIV-1-based, core particle with GFP (green fluorescent protein) as a reporter (HIVgfp). Using five different GBM primary cell cultures and three laboratory-adapted GBM cell lines, we showed that ZIKV/HIVgfp achieved a 4-6 times higher transduction efficiency compared to the commonly used VSV/HIVgfp. Transduced GBM cell cultures were monitored over a period of 9 days to identify GFP+ cells to study the oncolytic effect due to ZIKV/HIVgfp entry. Tests of GBM tumor specificity by transduction of GBM tumor and normal brain cells showed a high specificity for GBM cells.

SCARPET: site-specific quantification of methylated and nonmethylated adenosines reveals m6A stoichiometry

m6A has different stoichiometry at different positions in different mRNAs. However, the exact stoichiometry of m6A is difficult to measure. Here, we describe SCARPET (site-specific cleavage and radioactive-labeling followed by purification, exonuclease digestion, and thin-layer chromatography), a simple and streamlined biochemical assay for quantifying m6A at any specific site in any mRNA. SCARPET involves a site-specific cleavage of mRNA immediately 5' of an adenosine site in an mRNA. This site is radiolabeled with 32P, and after a series of steps to purify the RNA and to remove nonspecific signals, the nucleotide is resolved by TLC to visualize A and m6A at this site. Quantification of these spots reveals the m6A stoichiometry at the site of interest. SCARPET can be applied to poly(A)-enriched RNA, or preferably purified mRNA, which produces more accurate m6A stoichiometry measurements. We show that sample processing steps of SCARPET can be performed in a single day, and results in a specific and accurate measurement of m6A stoichiometry at specific sites in mRNA. Using SCARPET, we measure exact m6A stoichiometries in specific mRNAs and show that Zika genomic RNA lacks m6A at previously mapped sites. SCARPET will be useful for testing specific sites for their m6A stoichiometry and to assess how m6A stoichiometry changes in different conditions and cellular contexts.

A review on Zika vaccine development

Zika virus (ZIKV), which belongs to the Flavivirus family, is mainly transmitted via the bite of Aedes mosquitoes. In newborns, ZIKV infection can cause severe symptoms such as microcephaly, while in adults, it can lead to Guillain‒Barré syndrome (GBS). Due to the lack of specific therapeutic methods against ZIKV, the development of a safe and effective vaccine is extremely important. Several potential ZIKV vaccines, such as live attenuated, inactivated, nucleic acid, viral vector, and recombinant subunit vaccines, have demonstrated promising outcomes in clinical trials involving human participants. Therefore, in this review, the recent developmental progress, advantages and disadvantages of these five vaccine types are examined, and practical recommendations for future development are provided.

Rational design of a multivalent vaccine targeting arthropod-borne viruses using reverse vaccinology strategies

Viruses transmitted by arthropods, such as Dengue, Zika, and Chikungunya, represent substantial worldwide health threats, particularly in countries like India. The lack of approved vaccines and effective antiviral therapies calls for developing innovative strategies to tackle these arboviruses. In this study, we employed immunoinformatics methodologies, incorporating reverse vaccinology, to design a multivalent vaccine targeting the predominant arboviruses. Epitopes of B and T cells were recognized within the non-structural proteins of Dengue, Zika, and Chikungunya viruses. The predicted epitopes were enhanced with adjuvants β-defensin and RS-09 to boost the vaccine's immunogenicity. Sixteen distinct vaccine candidates were constructed, each incorporating epitopes from all three viruses. FUVAC-11 emerged as the most promising vaccine candidate through molecular docking and molecular dynamics simulations, demonstrating favorable binding interactions and stability. Its effectiveness was further evaluated using computational immunological studies confirming strong immune responses. The in silico cloning performed using the pET-28a(+) plasmid facilitates the future experimental implementation of this vaccine candidate, paving the way for potential advancements in combating these significant arboviral threats. However, further in vitro and in vivo studies are warranted to confirm the results obtained in this computational study, which highlights the effectiveness of immunoinformatics and reverse vaccinology in creating vaccines against major Arboviruses, offering a promising model for developing vaccines for other vector-borne diseases and enhancing global health security.

Zika virus: Antiviral immune response, inflammation, and cardiotonic steroids as antiviral agents

Zika virus (ZIKV) is a mosquito-borne virus first reported from humans in Nigeria in 1954. The first outbreak occurred in Micronesia followed by an outbreak in French Polynesia and another in Brazil when the virus was associated with numerous cases of severe neurological manifestations such as Guillain-Barre syndrome in adults and congenital zika syndrome in fetuses, particularly congenital microcephaly. Innate immunity is the first line of defense against ZIKV through triggering an antiviral immune response. Along with innate immune responses, a sufficient balance between anti- and pro-inflammatory cytokines and the amount of these cytokines are triggered to enhance the antiviral responses. Here, we reviewed the complex interplay between the mediators and signal pathways that coordinate antiviral immune response and inflammation as a key to understanding the development of the underlying diseases triggered by ZIKV. In addition, we summarize current and new therapeutic strategies for ZIKV infection, highlighting cardiotonic steroids as antiviral drugs for the development of this agent.

Detection and persistence of Zika virus in body fluids and associated factors: a prospective cohort study

This study aimed to analyze the detection and duration of the Zika virus (ZIKV) in plasma, urine, saliva, sweat, rectal swabs, vaginal secretions, breast milk, and semen and to explore risk factors associated with prolonged viral persistence. A prospective cohort study of symptomatic patients and their household contacts was conducted in Brazil from July 2017 to June 2019. A total of 260 individuals (184 women and 76 men) with confirmed ZIKV infection were enrolled and followed up for 12 months. ZIKV RNA was present in all body fluid specimens and detectable for extended periods in urine, sweat, rectal swabs, and semen. The longest detection duration was found in semen, with high viral loads in the specimens. ZIKV RNA clearance was associated with several factors, including age, sex, education level, body mass index, non-purulent conjunctivitis, joint pain, and whether the participant had a history of yellow fever vaccination. The influence of each of these factors on the low or fast viral clearance varied according to the specific body fluid under investigation. Recurrent ZIKV detection events after total viral clearance were observed in the cohort. Our findings provide valuable insights into the persistence and potential recurrence of ZIKV infection, highlighting the need for continued monitoring and follow-up of individuals infected with ZIKV and for effective prevention measures to reduce the risk of transmission.

Wulfenioidins D-N, Structurally Diverse Diterpenoids with Anti-Zika Virus Activity Isolated from Orthosiphon wulfenioides

Eleven diterpenoids, wulfenioidins D-N (1-11), classified into five distinct carbon skeletons with one unreported framework, and four modified abietane diterpenoids were isolated from the whole plant of Orthosiphon wulfenioides. The structures and absolute configurations were characterized by spectroscopic methods, single-crystal X-ray diffraction, and electronic circular dichroism analyses. Compounds 3 and 5 exhibited activity against Zika virus (ZIKV) with EC50 values of 8.07 and 8.50 μM, respectively, and showed no significant cytotoxicity toward Vero cells at 100 μM. Western blot and immunofluorescence experiments showed that compounds 3 and 5 interfered with the replication of the ZIKV by inhibiting the expression of the ZIKV envelope (E) protein.

Interplay between TRIM7 and antiviral immunity

TRIM7 has been demonstrated to have significant roles in promoting host defense against viral infections and regulating immune signaling pathways. As an E3 ubiquitin ligase, it catalyzes the ubiquitination of various substrates, including adaptor proteins (MAVS and STING) and transcription factors (NF-κB and IRF3), thereby exerting positive or negative regulation on immune signal pathways. However, viruses have developed immune evasion mechanisms to counteract TRIM7. Some viruses can inhibit TRIM7 function by targeting it for degradation or sequestering it away from its targets. Moreover, TRIM7 may even facilitate viral infection by ubiquitinating viral proteins, including envelope proteins that are critical for tissue and species tropism. A comprehensive understanding of the interaction between TRIM7 and antiviral immunity is crucial for the development of innovative treatments for viral diseases.

Proposal of Model for Evaluation of Viral Kinetics of African/Asian/Brazilian-Zika virus Strains (Step Growth Curve) in Trophoblastic Cell Lines

The Zika virus (ZIKV) epidemic brought new discoveries regarding arboviruses, especially flaviviruses, as ZIKV was described as sexually and vertically transmitted. The latter shows severe consequences for the embryo/fetus, such as congenital microcephaly and deficiency of the neural system, currently known as Congenital ZIKV Syndrome (CZS). To better understand ZIKV dynamics in trophoblastic cells present in the first trimester of pregnancy (BeWo, HTR-8, and control cell HuH-7), an experiment of viral kinetics was performed for African MR766 low passage and Asian-Brazilian IEC ZIKV lineages. The results were described independently and demonstrated that the three placental cells lines are permissive and susceptible to ZIKV. We noticed cytopathic effects that are typical in in vitro viral infection in BeWo and HTR-8. Regarding kinetics, MR766lp showed peaks of viral loads in 24 and 48 hpi for all cell types tested, as well as marked cells death after peak production. On the other hand, the HTR-8 lineage inoculated with ZIKV-IEC exhibited increased viral production in 144 hpi, with a peak between 24 and 96 hpi. Furthermore, IEC had peak variations of viral production for BeWo in 144 hpi. Considering such in vitro results, the hypothesis that maternal fetal transmission is probably a way of virus transmission between the mother and the embryo/fetus is maintained.