Zika Virus Research Articles

Using biosensors for the early diagnosis of arboviruses: a scoping review

Mapping scientific knowledge about the development of biosensors to be used for the early diagnosis of arboviruses. Scoping review based on studies searched in Lilacs, PubMed, SciELO and Web of Science databases. Nineteen (19) articles were selected, in total. The selected studies presented different types of biosensors used to detect arboviruses and their variants, with emphasis on dengue and Zika viruses. Electrochemical, optical and plasmon resonance were the biosensors mostly used for the aforementioned purpose due to their little margin of error. They enable reliable and fast diagnosis processes, besides being easy to handle and its low cost. Biosensors capable of identifying arboviruses are not yet available in health services, since they still require advancements to be achieved at practical research stages.

Orthoflaviviral Inhibitors in Clinical Trials, Preclinical In Vivo Efficacy Targeting NS2B-NS3 and Cellular Antiviral Activity via Competitive Protease Inhibition.

Orthoflaviviruses, including zika (ZIKV), West Nile (WNV), and dengue (DENV) virus, induce severely debilitating infections and contribute significantly to the global disease burden, yet no clinically approved antiviral treatments exist. This review offers a comprehensive analysis of small-molecule drug development targeting orthoflaviviral infections, with a focus on NS2B-NS3 inhibition. We systematically examined clinical trials, preclinical efficacy studies, and modes of action for various viral replication inhibitors, emphasizing allosteric and orthosteric drugs inhibiting NS2B-NS3 protease with in vivo efficacy and in vitro-tested competitive NS2B-NS3 inhibitors with cellular efficacy. Our findings revealed that several compounds with in vivo preclinical efficacy failed to show clinical antiviral efficacy. NS3-NS4B inhibitors, such as JNJ-64281802 and EYU688, show promise, recently entering clinical trials, underscoring the importance of developing novel viral replication inhibitors targeting viral machinery. To date, the only NS2B-NS3 inhibitor that has undergone clinical trials is doxycycline, however, its mechanism of action and clinical efficacy as viral growth inhibitor require additional investigation. SYC-1307, an allosteric inhibitor, exhibits high in vivo efficacy, while temoporfin and methylene blue represent promising orthosteric non-competitive inhibitors. Compound 71, a competitive NS2B-NS3 inhibitor, emerges as a leading preclinical candidate due to its high cellular antiviral efficacy, minimal cytotoxicity, and favorable in vitro pharmacokinetic parameters. Challenges remain in developing competitive NS2B-NS3 inhibitors, including appropriate biochemical inhibition assays as well as the selectivity and conformational flexibility of the protease, complicating effective antiviral treatment design.

A comprehensive overview on the crosstalk between microRNAs and viral pathogenesis and infection.

Infections caused by viruses as the smallest infectious agents, pose a major threat to global public health. Viral infections utilize different host mechanisms to facilitate their own propagation and pathogenesis. MicroRNAs (miRNAs), as small noncoding RNA molecules, play important regulatory roles in different diseases, including viral infections. They can promote or inhibit viral infection and have a pro-viral or antiviral role. Also, viral infections can modulate the expression of host miRNAs. Furthermore, viruses from different families evade the host immune response by producing their own miRNAs called viral miRNAs (v-miRNAs). Understanding the replication cycle of viruses and their relation with host miRNAs and v-miRNAs can help to find new treatments against viral infections. In this review, we aim to outline the structure, genome, and replication cycle of various viruses including hepatitis B, hepatitis C, influenza A virus, coronavirus, human immunodeficiency virus, human papillomavirus, herpes simplex virus, Epstein-Barr virus, Dengue virus, Zika virus, and Ebola virus. We also discuss the role of different host miRNAs and v-miRNAs and their role in the pathogenesis of these viral infections.

Chronic innate immune impairment and ZIKV persistence in the gastrointestinal tract during SIV infection in pigtail macaques.

Mosquito borne flaviviruses, including dengue (DENV) and Zika (ZIKV) viruses, have caused global epidemics in areas with high HIV prevalence due to the expanded geographic range of arthropod vectors. Despite the occurrence of large flavivirus outbreaks in countries with high HIV prevalence, there is little knowledge regarding the effects of flavivirus infection in people living with HIV (PLWH). Here, we use a pigtail macaque model of HIV/AIDS to investigate the impact of simian immunodeficiency virus (SIV)-induced immunosuppression on ZIKV replication and pathogenesis. Early acute SIV infection induced expansion of peripheral ZIKV cellular targets and increased innate immune activation and peripheral blood mononuclear cells (PBMC) from SIV infected macaques were less permissive to ZIKV infection in vitro. In SIV-ZIKV co-infected animals, we found increased persistence of ZIKV in the periphery and tissues corresponding to alterations in innate cellular (monocytes, neutrophils) recruitment to the blood and tissues, decreased anti-ZIKV immunity, and chronic peripheral inflammatory and innate immune gene expression. Collectively, these findings suggest that untreated SIV infection may impair cellular innate responses and create an environment of chronic immune activation that promotes prolonged ZIKV viremia and persistence in the gastrointestinal tract. These results suggest that PLWH or other immunocompromised individuals could be at a higher risk for chronic ZIKV replication, which in turn could increase the timeframe of ZIKV transmission. Thus, PLWH are important populations to target during the deployment of vaccine and treatment strategies against ZIKV.

Inhibitors of the small membrane (M) protein viroporin prevent Zika virus infection.

Flaviviruses, including Zika virus (ZIKV), are a significant global health concern, yet no licensed antivirals exist to treat disease. The small Membrane (M) protein plays well-defined roles during viral egress and remains within virion membranes following release and maturation. However, it is unclear whether M plays a functional role in this setting. Here, we show that M forms oligomeric membrane-permeabilising channels in vitro, with increased activity at acidic pH and sensitivity to the prototypic channel-blocker, rimantadine. Accordingly, rimantadine blocked an early stage of ZIKV cell culture infection. Structure-based channel models, comprising hexameric arrangements of two trans-membrane domain protomers were shown to comprise more stable assemblages than other oligomers using molecular dynamics (MD) simulations. Models contained a predicted lumenal rimantadine binding site, as well as a second druggable target region on the membrane-exposed periphery. In silico screening enriched for repurposed drugs/compounds predicted to bind to either one site or the other. Hits displayed superior potency in vitro and in cell culture compared with rimantadine, with efficacy demonstrably linked to virion-resident channels. Finally, rimantadine effectively blocked ZIKV viraemia in preclinical models, supporting that M constitutes a physiologically relevant target. This could be explored by repurposing rimantadine, or development of new M-targeted-therapies.

Investigating human monocyte adhesion, migration and transmigration and their modulation by Zika virus

Human circulating monocytes are established targets for Zika virus (ZIKV) infection. Because of their important migratory properties toward any tissues, including the central nervous system (CNS), a better understanding of the mechanisms underlying monocyte transmigration upon ZIKV infection is required. Here, we monitored adhesion, migration and transmigration properties of monocytes exposed to ZIKV. We found that ZIKV enhanced monocyte adhesion on collagen compared to mock-exposed samples, and that pharmacological inhibition of mDia and Cdc42 function induced a significant decrease of adhesion in both mock- and ZIKV-exposed monocytes. In contrast, monocyte migration through collagen was inhibited by most of the tested small molecules targeting regulators of actin polymerization, including Rac1, ROCK, Cdc42, mDia, Arp2/3, Myosin-II and LFA-1. ZIKV-exposed monocyte migration showed a very similar profile to that of their mock-exposed counterparts. Finally, assessment of monocyte transmigration through human cerebral microvascular endothelial cells (hCMEC/D3) showed dependency on Rac1, ROCK, and Cdc42, independently of their infection status. In contrast, we identified that BIRT377, an antagonist of LFA-1, significantly inhibited transmigration of ZIKV-exposed but not mock-exposed monocytes. As BIRT377 increased adhesion of ZIKV-exposed monocytes, we propose that LFA-1 might be involved in a post-adhesion step to enhance viro-induced transmigration. These data suggest that ZIKV exposure triggers specific migratory properties of monocytes that are not exploited under physiological conditions. This work provides further insights on virus-host interactions important for viral neuroinvasion and offers novel targets to specifically inhibit the infiltration of infected cells to the CNS. Summary sentenceMonocyte transmigration involves massive actin cytoskeleton reorganization regulated by small Rho GTPases and integrins, which can be subverted by viruses.

Exploring antiviral and antiparasitic activity of gold N-heterocyclic carbenes with thiolate ligands.

Gold(I) N-heterocyclic carbenes have been explored for their therapeutic potential against several diseases. Neglected tropical diseases, including leishmaniasis, Chagas disease, and viral infections, such as zika, mayaro, and chikungunya, urgently require new treatment options. The emergent SARS-CoV-2 also demands significant attention. Gold complexes have shown promise as alternative treatments for these conditions. Previously, gold(I)(1,3-bis(mesityl)imidazole-2-ylidene)Cl (AuIMesCl) demonstrated significant leishmanicidal and anti-Chikungunya virus activities. In this study, we synthesized and fully characterized a series of gold(I)(1,3-bis(mesityl)imidazole-2-ylidene)(SR) complexes, where SR includes thiolate donor species such as 1,3-thiazolidine-2-thione, 1,3-benzothiazole-2-thione, 2-mercaptopyrimidine, and 2-thiouracil. These compounds were stable in solution, and ligand exchange reactions with N-acetyl-L-cysteine indicated that complexes with SR ligands are more labile than those with chloride. Although the reactions are rapid, they reach equilibrium at varying molar ratios depending on the SR ligand. The increased lability of these compounds results in higher cytotoxicity to host cells, such as Vero E6 and bone marrow-differentiated macrophages, compared to AuIMesCl. Despite this, the compounds effectively inhibited viral replication, achieving 95.5% inhibition of Zika virus replication at 2 μM with 96% host cell viability. Although active at low concentrations (∼2 μM) against Leishmania (L.) amazonensis and Trypanosoma cruzi, their high cytotoxicity for macrophages confirmed AuIMesCl as a better candidate with a higher selectivity index. This work correlates the coordination chemistry of pyrimidines and thiazolidines with their in vitro biological activities against significant diseases.

The Raf kinase inhibitors Dabrafenib and Regorafenib impair Zika virus replication via distinct mechanisms.

There is an urgent need to develop effective therapeutics against re-emerging arboviruses associated with neurological disorders like Zika virus (ZIKV). We identified two FDA-approved kinase inhibitors, Dabrafenib and Regorafenib, as potent inhibitors of contemporary ZIKV strains at distinct stages of infection despite overlapping host targets. Both inhibitors reduced viral titers by ~1 to 2 log10 (~10-fold to 100-fold) with minimal cytotoxicity. Furthermore, we show that Dabrafenib inhibits ZIKV RNA replication whereas Regorafenib inhibits ZIKV translation and egress. Regorafenib has the added benefit of limiting NS1 secretion, which contributes to the pathogenesis and disease progression of several flaviviruses. Because these inhibitors affect distinct post-entry steps of ZIKV infection, their therapeutic potential may be amplified by combination therapy and likely does not require prophylactic administration. This study provides further insight into ZIKV-host interactions and has implications for the development of novel antivirals against ZIKV and possibly other flaviviruses.

Manifestações clínicas e o manejo da infecção congênita pelo Zika Vírus: Uma revisão sistemática

Objective: The general objective of the present study is to analyze the scientific production on Congenital Zika Virus Infection, seeking to identify the main clinical manifestations, as well as the main methods used in the treatment of this pathology. Methodology: It is a systematic review focused on understanding the main aspects of Congenital Zika Virus Infection. The research was guided by the question: "What are the main signs and symptoms of congenital Zika virus infection in the pediatric population, as well as what are the therapeutic resources used in clinical practice?" . To find answers, searches were performed in the PubMed database using three descriptors combined with the Boolean term "AND". This resulted in 010 articles. 12 articles were selected for analysis. Results: Congenital Zika syndrome (CZS) emerges as a complex and multifaceted challenge whose implications go beyond the boundaries of public health. Babies exposed to the Zika virus during pregnancy face a range of clinical manifestations, from microcephaly to eye anomalies and neurological disorders. Prevention, therefore, takes on a crucial role: educating pregnant women about the risks and promoting protective measures, such as the use of repellents and mosquito nets, is imperative. Conclusion: Although we do not yet have a licensed Zika vaccine, research efforts continue to explore this possibility. In addition, long-term surveillance is essential to fully understand the effects of the virus. In this scenario, awareness, interdisciplinary collaboration, and a commitment to the well-being of future generations are our best allies in the fight against this potentially devastating syndrome.

Application of diceCT to Study the Development of the Zika Virus-Infected Mouse Brain.

Zika virus (ZIKV) impacts the developing brain. Here, a technique was applied to define, in 3D, developmental changes in the brains of ZIKV-infected mice. Postnatal day 1 mice were uninfected or ZIKV-infected, then analysed by iodine staining and micro-CT scanning (diffusible iodine contrast-enhanced micro-CT; diceCT) at 3-, 6-, and 10-days post-infection (dpi). Multiple brain regions were visualised using diceCT: the olfactory bulb, cerebrum, hippocampus, midbrain, interbrain, and cerebellum, along with the lens and retina of the eye. Brain regions were computationally segmented and quantitated, with increased brain volumes and developmental time in uninfected mice. Conversely, in ZIKV-infected mice, no quantitative differences were seen at 3 or 6 dpi when there were no clinical signs, but qualitatively, diverse visual defects were identified at 6-10 dpi. By 10 dpi, ZIKV-infected mice had significantly lower body weight and reduced volume of brain regions compared to 10 dpi-uninfected or 6 dpi ZIKV-infected mice. Nissl and immunofluorescent Iba1 staining on post-diceCT tissue were successful, but RNA extraction was not. Thus, diceCT shows utility for detecting both 3D qualitative and quantitative changes in the developing brain of ZIKV-infected mice, with the benefit, post-diceCT, of retaining the ability to apply traditional histology and immunofluorescent analysis to tissue.

Cleavage of SQSTM1/p62 by the Zika virus protease NS2B3 prevents autophagic degradation of viral NS3 and NS5 proteins

ABSTRACT Macroautophagy/autophagy plays a crucial role in inhibiting viral replication and regulating the host’s immune response. The autophagy receptor SQSTM1/p62 (sequestosome 1) restricts viral replication by directing specific viral proteins to phagophores for degradation. In this study, we investigate the reciprocal relationship between Zika virus (ZIKV) and selective autophagy mediated by SQSTM1/p62. We show that NS2B3 protease encoded by ZIKV cleaves human SQSTM1/p62 at arginine 265 (R265). This cleavage also occurs with endogenous SQSTM1 in ZIKV-infected cells. Furthermore, overexpression of SQSTM1 inhibits ZIKV replication in A549 cells, while its absence increases viral titer. We have also shown that SQSTM1 impedes ZIKV replication by interacting with NS3 and NS5 and directing them to autophagic degradation, and that NS2B3-mediated cleavage could potentially alter this antiviral function of SQSTM1. Taken together, our study highlights the role of SQSTM1-mediated selective autophagy in the host’s antiviral defense against ZIKV and uncovers potential viral evasion strategies that exploit the host’s autophagic machinery to ensure successful infection. Abbreviation: Cas9: CRISPR-associated protein 9; Co-IP: co-immunoprecipitation; CRISPR: clustered regularly interspaced short palindromic repeats; DENV: dengue virus; GFP: green fluorescent protein; IFA: indirect immunofluorescence assay; KIR: KEAP1-interacting region; KO: knockout; LIR: MAP1LC3/LC3-interacting region; mAb: monoclonal antibody; NBR1: NBR1 autophagy cargo receptor; OPTN: optineurin; pAb: polyclonal antibody; PB1: Phox/BEM1 domain; R265A, a SQSTM1 construct with the arginine (R) residue at position 265 replaced with glutamic acid (A); SQSTM1: sequestosome 1; SQSTM1-C, C-terminal fragment of SQSTM1; SQSTM1-N, N-terminal fragment of SQSTM1; SVV: Seneca Valley virus; TAX1BP1: Tax1 binding protein 1; TBD: TRAF6-binding domain; TCID50: 50% tissue culture infective dose; UBA: ubiquitin-associated domain; Ub: ubiquitin; WT: wild type; ZIKV: Zika virus; ZZ: ZZ-type zinc finger domain.

Ubiquitination of NS1 Confers Differential Adaptation of Zika Virus in Mammalian Hosts and Mosquito Vectors.

Arboviruses, transmitted by medical arthropods, pose a serious health threat worldwide. During viral infection, Post Translational Modifications (PTMs) are present on both host and viral proteins, regulating multiple processes of the viral lifecycle. In this study, a mammalian E3 ubiquitin ligase WWP2 (WW domain containing E3 ubiquitin ligase 2) is identified, which interacts with the NS1 protein of Zika virus (ZIKV) and mediates K63 and K48 ubiquitination of Lys 265 and Lys 284, respectively. WWP2-mediated NS1 ubiquitination leads to NS1 degradation via the ubiquitin-proteasome pathway, thereby inhibiting ZIKV infection in mammalian hosts. Simultaneously, it is found Su(dx), a protein highly homologous to host WWP2 in mosquitoes, is capable of ubiquitinating NS1 in mosquito cells. Unexpectedly, ubiquitination of NS1 in mosquitoes does not lead to NS1 degradation; instead, it promotes viral infection in mosquitoes. Correspondingly, the NS1 K265R mutant virus is less infectious to mosquitoes than the wild-type (WT) virus. The above results suggest that the ubiquitination of the NS1 protein confers different adaptations of ZIKV to hosts and vectors, and more importantly, this explains why NS1 K265-type strains have become predominantly endemic in nature. This study highlights the potential application in antiviral drug and vaccine development by targeting viral proteins' PTMs.

Modeling the Spatial Dynamics and Human Mobility in Zika Virus Transmission: A Review

Spatial dynamics and human mobility significantly influence the transmission dynamics of vector-borne diseases like Zika virus. This paper reviews advancements in mathematical modeling that integrate spatial factors and human movement to enhance our understanding of disease transmission dynamics. Traditional SEIR (Susceptible-Exposed-Infectious-Recovered) models have been foundational but lack spatial heterogeneity and human mobility considerations. Recent studies have addressed these limitations by developing spatially explicit models that incorporate local interactions, environmental conditions, and human mobility patterns. By synthesizing findings from these studies, we identify strengths, limitations, and future research directions for improving predictive modeling of Zika virus transmission. Key insights include the amplifying effect of local interactions on disease spread and the critical role of human mobility networks in shaping transmission pathways. Addressing remaining challenges, such as refining spatial modeling techniques and integrating real-time data sources, will enhance the accuracy and applicability of spatial disease models in informing public health strategies.

Two novel compounds inhibit Flavivirus infection in vitro and in vivo by targeting lipid metabolism.

This study is the inaugural utilization of a lipid compound library in antiviral drug screening. Two lipid compounds, isobavachalcone (IBC) and corosolic acid (CA), emerged from the screening, exhibiting substantial inhibitory effects on the Japanese encephalitis virus (JEV) proliferation in vitro. In vivo experiments underscored their efficacy, with IBC and CA reducing viral loads in the brain and mitigating JEV-induced histopathological changes, effectively shielding mice from fatal JEV infection. Intriguingly, IBC and CA may activate 5'-adenosine monophosphate (AMP)-activated protein kinase (AMPK) by binding to its active site, curtailing the synthesis of lipid substances, and thus suppressing JEV proliferation. This indicates AMPK as a potential antiviral target. Remarkably, IBC and CA demonstrated suppression of multiple viruses, including Flaviviruses (JEV and Zika virus), porcine herpesvirus (pseudorabies virus), and coronaviruses (porcine deltacoronavirus and porcine epidemic diarrhea virus), suggesting their potential as broad-spectrum antiviral agents. These findings shed new light on the potential applications of these compounds in antiviral research.

Aptamer and aptasensor technology for diagnosis of infectious diseases: A mini review

BackgroundAptamers are not so new a concept, however, it is scarcely discussed by medical fraternity. Aptamers are potent, new identification molecules set to rope in a new technique in the diagnostic arena. Aptamers have started almost a revolution in diagnostic assays since their discovery in the 90s. (Radu S. Current and previous disease outbreaks around the world, U.S. News & World Report. 2020 Mar 13 [cited 2024 Jun 17]. Available from: https://www.usnews.com/news/best-countries/slideshows/20-pandemic-and-epidemic-diseases-according-to-who) provides an overview of pandemics and epidemics as reported by the WHO. It is interesting to note that several endemic and epidemic diseases viz. Chikungunya, Cholera, Crimean-Congo haemorrhagic fever, Ebola virus disease, Hendra virus infection, Influenza, Lassa fever, Marburg virus disease, Meningitis, MERS-CoV (Middle East Respiratory Syndrome Corona Virus), Monkeypox, Nipah virus infection, Novel coronavirus, Plague, Rift Valley fever, SARS (Severe Acute Respiratory Syndrome), Smallpox, Tularaemia, Yellow fever, and Zika virus disease have been identified by the WHO and are being explored for applicability of aptamer technology in their identification. ObjectivesOne of the most important necessities to control epidemic or pandemic diseases is early diagnosis. However, the majority of the diagnostic tests for these diseases are available only in tertiary care centres. The objective of this review is to discuss the potential of aptamer technology to provide undemanding, simple, specific, sensitive, and cost-effective diagnostic assays that are useable in remote and field conditions. ContentHere, we discuss recent advances and approaches in aptamer and aptamer engineering useful in the diagnosis of infectious and non-infectious conditions. This review also discusses a few sensing discoveries which are a gift of advanced engineering and technology using optical and electrochemical aptasensors. It's still a long way to go, and we need to take into account the technological challenges being faced by aptamer-aptasensor technology.

Y-switch: a spring-loaded synthetic gene switch for robust DNA/RNA signal amplification and detection.

Nucleic acid tests (NATs) are essential for biomedical diagnostics. Traditional NATs, often complex and expensive, have prompted the exploration of toehold-mediated strand displacement (TMSD) circuits as an economical alternative. However, the wide application of TMSD-based reactions is limited by 'leakage'-the spurious activation of the reaction leading to high background signals and false positives. Here, we introduce the Y-Switch, a new TMSD cascade design that recognizes a custom nucleic acid input and generates an amplified output. The Y-Switch is based on a pair of thermodynamically spring-loaded DNA modules. The binding of a predefined nucleic acid target triggers an intermolecular reaction that activates a T7 promoter, leading to the perpetual transcription of a fluorescent aptamer that can be detected by a smartphone camera. The system is designed to permit the selective depletion of leakage byproducts to achieve high sensitivity and zero-background signal in the absence of the correct trigger. Using Zika virus (ZIKV)- and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-derived nucleic acid sequences, we show that the assay generates a reliable target-specific readout. Y-Switches detect native RNA under isothermal conditions without reverse transcription or pre-amplification, with a detection threshold as low as ∼200 attomole. The modularity of the assay allows easy re-programming for the detection of other targets by exchanging a single sequence domain. This work provides a low-complexity and high-fidelity synthetic biology tool for point-of-care diagnostics and for the construction of more complex biomolecular computations.

Employing Machine Learning-Based QSAR for Targeting Zika Virus NS3 Protease: Molecular Insights and Inhibitor Discovery.

Zika virus infection is a mosquito-borne viral disease that has become a global health concern recently. Zika virus belongs to the Flavivirus genus and is primarily transmitted by Aedes mosquitoes. Prevention of Zika virus infection involves avoiding mosquito bites by using repellent, wearing protective clothing, and staying in screened areas, especially for pregnant women. Treatment focuses on managing symptoms with rest, fluids, and acetaminophen, with close monitoring for pregnant women. Currently, there is no specific antiviral treatment or vaccine for the Zika virus, highlighting the importance of prevention strategies to control its spread. Therefore, in this study, the Zika virus non-structural protein NS3 was targeted to inhibit Zika infection by identifying the novel inhibitor through an in silico approach. Here, 2864 natural compounds were screened using a machine learning-based QSAR model, and later docking was performed to select the potential target. Subsequently, Tanimoto similarity and clustering were performed to obtain the potential target. The three most potential compounds were obtained: (a) 5297, (b) 432449, and (c) 85137543. The protein-ligand complex's stability and flexibility were then investigated by dynamic modelling. The 300 ns simulation showed that 5297 exhibited the steadiest deviation and constant creation of hydrogen bonds. Compared to the other compounds, 5297 demonstrated a superior binding free energy (ΔG = -20.81 kcal/mol) with the protein when the MM/GBSA technique was used. The study determined that 5297 showed significant therapeutic potential and justifies further experimental investigation as a possible inhibitor of the NS2B-NS3 protease target implicated in Zika virus infection.

Zika virus NS5 protein inhibits type I interferon signaling via CRL3 E3 ubiquitin ligase-mediated degradation of STAT2

The ZIKA virus (ZIKV) evades the host immune response by degrading STAT2 through its NS5 protein, thereby inhibiting type I interferon (IFN)-mediated antiviral immunity. However, the molecular mechanism underlying this process has remained elusive. In this study, we performed a genome-wide CRISPR/Cas9 screen, revealing that ZSWIM8 as the substrate receptor of Cullin3-RING E3 ligase is required for NS5-mediated STAT2 degradation. Genetic depletion of ZSWIM8 and CUL3 substantially impeded NS5-mediated STAT2 degradation. Biochemical analysis illuminated that NS5 enhances the interaction between STAT2 and the ZSWIM8-CUL3 E3 ligase complex, thereby facilitating STAT2 ubiquitination. Moreover, ZSWIM8 knockout endowed A549 and Huh7 cells with partial resistance to ZIKV infection and protected cells from the cytopathic effects induced by ZIKV, which was attributed to the restoration of STAT2 levels and the activation of IFN signaling. Subsequent studies in a physiologically relevant model, utilizing human neural progenitor cells, demonstrated that ZSWIM8 depletion reduced ZIKV infection, resulting from enhanced IFN signaling attributed to the sustained levels of STAT2. Our findings shed light on the role of ZIKV NS5, serving as the scaffold protein, reprograms the ZSWIM8-CUL3 E3 ligase complex to orchestrate STAT2 proteasome-dependent degradation, thereby facilitating evasion of IFN antiviral signaling. Our study provides unique insights into ZIKV-host interactions and holds promise for the development of antivirals and prophylactic vaccines.

Prevalence of Flavivirus and Alphavirus in bats captured in the state of Yucatan, southeastern Mexico

Flavivirus (family Flaviviridae) and Alphavirus (family Togaviridae) are mosquito-borne viruses that poses a significant risk to public health worldwide. Examples of these viruses include Dengue virus (DENV) and Zika virus (ZIKV) in the Flavivirus genus, and Chikungunya virus (CHIKV) in the Alphavirus genus. The potential contribution of bats in the mosquito-to-human transmission cycle of these viral genera in the tropics has not been studied. Here, a total of 144 bats belonging to three families (Emballonuridae, Phyllostomidae, and Molossidae) and six species were captured for one year using mist nets in sites with different landscapes (forest and grassland) in the state of Yucatan, southeastern Mexico. Blood samples and rectal and oral swabs were collected to detect Flavivirus and Alphavirus RNA genomes through RT-PCR. Flavivirus RNA was detected in 53 individuals (36.8%; 95% CI: 29.4%-44.9%), and Alphavirus RNA was detected in 59 individuals (40.1%; 95% CI: 33.2%-49.2%). The sequences obtained were consistent with ZIKV and DENV, into the Flavivirus, and CHIKV into the Alphavirus positive samples. The prevalence of both Flavivirus and Alphavirus was higher during the dry season compared with the rainy season. This high positivity rate, highlighted in both Flavivirus and Alphavirus, suggests a potential contribution of bats in the circulation of these viral genera in sylvatic environments. Seasonal variation in viral genera prevalence, with higher prevalence during dry seasons than rainy seasons, may suggest specific viral activity patterns in response to climatic conditions.

Importin-7-dependent nuclear translocation of the Flavivirus core protein is required for infectious virus production.

Flaviviridae is a family of positive-stranded RNA viruses, including human pathogens, such as Japanese encephalitis virus (JEV), dengue virus (DENV), Zika virus (ZIKV), and West Nile virus (WNV). Nuclear localization of the viral core protein is conserved among Flaviviridae, and this feature may be targeted for developing broad-ranging anti-flavivirus drugs. However, the mechanism of core protein translocation to the nucleus and the importance of nuclear translocation in the viral life cycle remain unknown. We aimed to identify the molecular mechanism underlying core protein nuclear translocation. We identified importin-7 (IPO7), an importin-β family protein, as a nuclear carrier for Flaviviridae core proteins. Nuclear import assays revealed that core protein was transported into the nucleus via IPO7, whereas IPO7 deletion by CRISPR/Cas9 impaired their nuclear translocation. To understand the importance of core protein nuclear translocation, we evaluated the production of infectious virus or single-round-infectious-particles in wild-type or IPO7-deficient cells; both processes were significantly impaired in IPO7-deficient cells, whereas intracellular infectious virus levels were equivalent in wild-type and IPO7-deficient cells. These results suggest that IPO7-mediated nuclear translocation of core proteins is involved in the release of infectious virus particles of flaviviruses.