Zika Virus Strains Research Articles

Zika viruses encode 5′ upstream open reading frames affecting infection of human brain cells

Zika virus (ZIKV), an emerging mosquito-borne flavivirus, is associated with congenital neurological complications. Here, we investigate potential pathological correlates of virus gene expression in representative ZIKV strains through RNA sequencing and ribosome profiling. In addition to the single long polyprotein found in all flaviviruses, we identify the translation of unrecognised upstream open reading frames (uORFs) in the genomic 5′ region. In Asian/American strains, ribosomes translate uORF1 and uORF2, whereas in African strains, the two uORFs are fused into one (African uORF). We use reverse genetics to examine the impact on ZIKV fitness of different uORFs mutant viruses. We find that expression of the African uORF and the Asian/American uORF1 modulates virus growth and tropism in human cortical neurons and cerebral organoids, suggesting a potential role in neurotropism. Although the uORFs are expressed in mosquito cells, we do not see a measurable effect on transmission by the mosquito vector in vivo. The discovery of ZIKV uORFs sheds new light on the infection of the human brain cells by this virus and raises the question of their existence in other neurotropic flaviviruses.

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.

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.

Replication properties of a contemporary Zika virus from West Africa.

Zika virus (ZIKV) has become a global health problem over the past decade due to the extension of the geographic distribution of the Asian/American genotype. Recent epidemics of Asian/American ZIKV have been associated with developmental disorders in humans. There is mounting evidence that African ZIKV may be associated with increased fetal pathogenicity necessitating to pay a greater attention towards currently circulating viral strains in sub-Saharan Africa. Here, we generated an infectious molecular clone GUINEA-18 of a recently transmitted human ZIKV isolate from West Africa, ZIKV-15555. The available infectious molecular clone MR766MC of historical African ZIKV strain MR766-NIID was used for a molecular clone-based comparative study. Viral clones GUINEA-18 and MR766MC were compared for their ability to replicate in VeroE6, A549 and HCM3 cell lines. There was a lower replication rate for GUINEA-18 associated with weaker cytotoxicity and reduced innate immune system activation compared with MR766MC. Analysis of chimeric viruses between viral clones stressed the importance of NS1 to NS4B proteins, with a particular focus of NS4B on GUINEA-18 replicative properties. ZIKV has developed strategies to prevent cytoplasmic stress granule formation which occurs in response to virus infection. GUINEA-18 was greatly efficient in inhibiting stress granule assembly in A549 cells subjected to a physiological stressor, with NS1 to NS4B proteins also being critical in this process. The impact of these GUINEA-18 proteins on viral replicative abilities and host-cell responses to viral infection raises the question of the role of nonstructural proteins in the pathogenicity of currently circulating ZIKV in sub-Saharan Africa.

Zafirlukast, as a viral inactivator, potently inhibits infection of several flaviviruses, including Zika virus, dengue virus, and yellow fever virus.

Zika virus (ZIKV) is one of the mosquito-borne flaviviruses that exhibits a unique tropism to nervous systems and is associated with Guillain-Barre syndrome and congenital Zika syndrome (CZS). Dengue virus (DENV) and yellow fever virus (YFV), the other two mosquito-borne flaviviruses, have also been circulating for a long time and cause severe diseases, such as dengue hemorrhagic fever and yellow fever, respectively. However, there are no safe and effective antiviral drugs approved for the treatment of infections or coinfections of these flaviviruses. Here, we found that zafirlukast, a pregnancy-safe leukotriene receptor antagonist, exhibited potent antiviral activity against infections of ZIKV strains from different lineages in different cell lines, as well as against infections of DENV-2 and YFV 17D. Mechanistic studies demonstrated that zafirlukast directly and irreversibly inactivated these flaviviruses by disrupting the integrity of the virions, leading to the loss of viral infectivity, hence inhibiting the entry step of virus infection. Considering its efficacy against flaviviruses, its safety for pregnant women, and its neuroprotective effect, zafirlukast is a promising candidate for prophylaxis and treatment of infections or coinfections of ZIKV, DENV, and YFV, even in pregnant women.

Integrated re-analysis of transcriptomic and proteomic datasets reveals potential mechanisms for Zika viral-based oncolytic therapy in neuroblastoma.

Paediatric neuroblastoma and brain tumours account for a third of all childhood cancer-related mortality. High-risk neuroblastoma is highly aggressive and survival is poor despite intensive multi-modal therapies with significant toxicity. Novel therapies are desperately needed. The Zika virus (ZIKV) can access the nervous system and there is growing interest in employing ZIKV as a potential therapy against paediatric nervous system tumours, including neuroblastoma. Here, we perform extensive data mining, integration and re-analysis of ZIKV infection datasets to highlight molecular mechanisms that may govern the oncolytic response in neuroblastoma cells. We collate infection data of multiple neuroblastoma cell lines by different ZIKV strains from a body of published literature to inform the susceptibility of neuroblastoma to the ZIKV oncolytic response. Integrating published transcriptomics, interaction proteomics, dependency factor and compound datasets we propose the involvement of multiple host systems during ZIKV infection. Through data mining of published literature, we observed most paediatric neuroblastoma cell lines to be highly susceptible to ZIKV infection and propose the PRVABC59 ZIKV strain to be the most promising candidate for neuroblastoma oncolytic virotherapy. ZIKV induces TNF signalling, lipid metabolism, the Unfolded Protein Response (UPR), and downregulates cell cycle and DNA replication processes. ZIKV infection is dependent on sterol regulatory element binding protein (SREBP)-regulated lipid metabolism and three protein complexes; V-ATPase, ER Membrane Protein Complex (EMC) and mammalian translocon. We propose ZIKV non-structural protein 4B (NS4B) as a likely mediator of ZIKVs interaction with IRE1-mediated UPR, lipid metabolism and mammalian translocon. Our work provides a significant understanding of ZIKV infection in neuroblastoma cells, which will facilitate the progression of ZIKV-based oncolytic virotherapy through pre-clinical research and clinical trials.

Characterization of the infectivity of an Indonesian Zika virus strain in mammalian cell lines

Objective: To characterize the infection patterns and growth characteristics of the Zika virus (ZIKV) strain JMB-185 from Indonesia in various mammalian cell lines. Methods: ZIKV was grown in human (A549, HEK293, HepG2, Huh7, Jurkat, and THP-1) and non-human mammalian (RAW264.7, Vero, and Vero76) cell lines. Viral replication kinetics were measured using plaque assay, while intra- and extracellular viral RNA concentrations were assessed using RT-PCR. Flow cytometry was used to quantify the infected cells and cell viability was measured using an MTT assay. The ability of ZIKV to infect cell lines was visualized using a fluorescence immunostaining assay. Results: This ZIKV strain preferentially infected the lung, kidney, and liver cell lines A549, HEK293, Huh7, Vero, and Vero76, but not the immune cells Jurkat, RAW264.7, and THP-1. By contrast, the ZIKV showed no sign of infection in HepG2 cells, while maintaining viral titer over 3 days post-infection, with no infection recorded in immunostaining, no increase in viral RNA, and no indication of cell deterioration. Conclusions: The Indonesian ZIKV strain has a similar infection profile as other strains, except for its poor infectivity on HepG2 cells. Information on the growth characteristics of Indonesia ZIKV will help expand our understanding of the biology of ZIKV which will be useful for various applications including antiviral discovery.

The pathogenicity and potential risk evaluation of Zika virus to cause mysterious "Disease X": A brief report.

Disease X is included to represent an unknown pathogen that has the potential to spread globally and trigger significant epidemics. The World Health Organization (WHO) and the Global Alliance for Vaccine and Immunization (GAVI) recommend 10 potential disease organisms responsible for disease X. Among them, the Zika virus (ZIKV) is one of the potential organisms. The present work aimed to evaluate the current pathogenicity and potential risk of the ZIKV for public health emergencies. We performed a brief review of existing literature from available sources using Zika fever, Zika virus, and Flaviviridae as keywords and extracted relevant information for this review. The primary way that the ZIKV transmits to humans is by mosquito bites (Aedes aegypti and Aedes albopictus). Typically, Aedes mosquitoes bite during the day. As an RNA virus, the ZIKV is well-known for its rapid mutation rate. ZIKV strains or variations can arise due to genomic mutations, and they occur through various processes, including replication errors, recombination, and selection pressure. Nowadays, the ZIKV has also evolved into a global pandemic because the four-amino acid sequence fits the envelope protein's 154 glycosylation motif, which may be involved in virulence. There is no specific medicine or vaccine available for the prevention or treatment of ZIKV infection. Therefore, personal protective measures should be the way to prevent ZIKV disease. Therefore, avoiding exposure is the best way to prevent problems from ZIKV to mosquitoes.

Structural basis of Zika virus NS1 multimerization and human antibody recognition

Zika virus (ZIKV) belongs to the Flavivirus genus of the Flaviviridae family along with the four serotypes of dengue virus (DENV1–4). The recent global outbreaks of contemporary ZIKV strains demonstrated that infection can lead to neurological sequelae in adults and severe abnormalities in newborns that were previously unreported with ancestral strains. As such, there remains an unmet need for efficacious vaccines and antiviral agents against ZIKV. The non-structural protein 1 (NS1) is secreted from the infected cell and is thought to be associated with disease severity besides its proven usefulness for differential diagnoses. However, its physiologically relevant structure and pathogenesis mechanisms remain unclear. Here, we present high-resolution cryoEM structures of ZIKV recombinant secreted NS1 (rsNS1) and its complexes with three human monoclonal antibodies (AA12, EB9, GB5), as well as evidence for ZIKV infection-derived secreted NS1 (isNS1) binding to High Density Lipoprotein (HDL). We show that ZIKV rsNS1 forms tetramers and filamentous repeats of tetramers. We also observed that antibody binding did not disrupt the ZIKV NS1 tetramers as they bound to the wing and connector subdomain of the β-ladder. Our study reveals new insights into NS1 multimerization, highlights the need to distinguish the polymorphic nature of rsNS1 and isNS1, and expands the mechanistic basis of the protection conferred by antibodies targeting NS1.

Abstract 6660: The novel codon-modified Zika virus CDX-602 shows anti-tumor efficacy and remodels the tumor microenvironment in preclinical models

Abstract Multiple oncolytic viruses have been shown to induce multifaceted changes in the tumor microenvironment, that ultimately support induction of anti-tumor immune responses. We have previously demonstrated that CodaLytic, a codon-modified influenza virus, can kickstart the cancer immunity cycle at various steps in several mouse models with differing baseline immune contextures. Here, we are describing the activity of a new codon-modified virotherapeutic derived from the same synthetic viral engineering platform [Coleman et al., Science 2008]. Zika virus strain MR766 was synthetically codon-modified at 664 positions in the envelop gene to yield CDX-602. Virus was originally passaged in Vero cells and working stocks were expanded in BSR-T7 cells for in vivo use after titration on MA104.1 cells. Efficacy after intratumoral injection of 107 PFU/dose CDX-602 alone or in combination with 200 μg/dose αPD-1 blockade (RMP1-14, i.p.) was determined in subcutaneous B16-F10 melanoma and orthotopic EMT6 breast cancer models (n = 10). Changes in the tumor immune infiltrate were characterized using flow cytometry 6 or 8 days after treatment initiation, respectively (n = 5). In the immunotherapy-resistant B16-F10 model, CDX-602 monotherapy led to highly reproducible tumor growth inhibition (TGI, 52%, p < 0.0001 vs vehicle control), resulting in modest, but significant prolongation of median survival (25%, p < 0.01). Anti-tumor efficacy correlated with increased tumor immune infiltration with CD4+ and CD8+ T cells (R2 = 0.68 and 0.67, respectively, p < 0.01). Importantly, frequencies of cross-presenting dendritic cells (cDC) were increased 3.8-fold (p < 0.0001) after virus treatment, while no compensatory influx of CD206+ macrophages was observed, suggesting immune contexture changes conducive to anti-tumor immune induction. Efficacy was confirmed in the EMT6 model, in which monotherapy TGI was 44% and thus on par with αPD-1 blockade (50%, both p < 0.0001 vs control). Combination viroimmunotherapy in this model further improved efficacy, leading to 71% TGI and a doubling in complete regressions to 40%. Inclusion of CDX-602 in the treatment regimen led to similar changes in immune infiltration, in particular recruitment of CD8+ T cells and cDCs (9.7-fold and 6.9-fold increase after combination, respectively). Additional ex vivo analyses to confirm induction of anti-tumor immune responses are ongoing. Taken together, this preclinical data establishes CDX-602 as a novel virotherapeutic candidate that engages multiple mechanisms of action that contribute to anti-tumor activity. CDX-602 is the second virotherapeutic candidate derived from Codagenix’s codon modification platform, further supporting the utility of this synthetic viral engineering technology for viroimmunotherapy of cancer and highlighting its potential across multiple viral species. Citation Format: Nusrat Jahan, Yiwen Zhao, Katarina Blagovic, Ying Wang, J Robert Coleman, Steffen Mueller, Johanna K. Kaufmann. The novel codon-modified Zika virus CDX-602 shows anti-tumor efficacy and remodels the tumor microenvironment in preclinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6660.

The Chimeric Chaoyang-Zika Vaccine Candidate Is Safe and Protective in Mice.

Zika virus (ZIKV) is an emerging flavivirus that causes congenital syndromes including microcephaly and fetal demise in pregnant women. No commercial vaccines against ZIKV are currently available. We previously generated a chimeric ZIKV (ChinZIKV) based on the Chaoyang virus (CYV) by replacing the prME protein of CYV with that of a contemporary ZIKV strain GZ01. Herein, we evaluated this vaccine candidate in a mouse model and showed that ChinZIKV was totally safe in both adult and suckling immunodeficient mice. No viral RNA was detected in the serum of mice inoculated with ChinZIKV. All of the mice inoculated with ChinZIKV survived, while mice inoculated with ZIKV succumbed to infection in 8 days. A single dose of ChinZIKV partially protected mice against lethal ZIKV challenge. In contrast, all the control PBS-immunized mice succumbed to infection after ZIKV challenge. Our results warrant further development of ChinZIKV as a vaccine candidate in clinical trials.

Zika Virus-A Reemerging Neurotropic Arbovirus Associated with Adverse Pregnancy Outcomes and Neuropathogenesis.

Zika virus (ZIKV) is a reemerging flavivirus that is primarily spread through bites from infected mosquitos. It was first discovered in 1947 in sentinel monkeys in Uganda and has since been the cause of several outbreaks, primarily in tropical and subtropical areas. Unlike earlier outbreaks, the 2015-2016 epidemic in Brazil was characterized by the emergence of neurovirulent strains of ZIKV strains that could be sexually and perinatally transmitted, leading to the Congenital Zika Syndrome (CZS) in newborns, and Guillain-Barre Syndrome (GBS) along with encephalitis and meningitis in adults. The immune response elicited by ZIKV infection is highly effective and characterized by the induction of both ZIKV-specific neutralizing antibodies and robust effector CD8+ T cell responses. However, the structural similarities between ZIKV and Dengue virus (DENV) lead to the induction of cross-reactive immune responses that could potentially enhance subsequent DENV infection, which imposes a constraint on the development of a highly efficacious ZIKV vaccine. The isolation and characterization of antibodies capable of cross-neutralizing both ZIKV and DENV along with cross-reactive CD8+ T cell responses suggest that vaccine immunogens can be designed to overcome these constraints. Here we review the structural characteristics of ZIKV along with the evidence of neuropathogenesis associated with ZIKV infection and the complex nature of the immune response that is elicited by ZIKV infection.

Repurposing of Zika virus live-attenuated vaccine (ZIKV-LAV) strains as oncolytic viruses targeting human glioblastoma multiforme cells

Glioblastoma multiforme (GBM) is the most common malignant primary brain cancer affecting the adult population. Median overall survival for GBM patients is poor (15 months), primarily due to high rates of tumour recurrence and the paucity of treatment options. Oncolytic virotherapy is a promising treatment alternative for GBM patients, where engineered viruses selectively infect and eradicate cancer cells by inducing cell lysis and eliciting robust anti-tumour immune response. In this study, we evaluated the oncolytic potency of live-attenuated vaccine strains of Zika virus (ZIKV-LAV) against human GBM cells in vitro. Our findings revealed that Axl and integrin αvβ5 function as cellular receptors mediating ZIKV-LAV infection in GBM cells. ZIKV-LAV strains productively infected and lysed human GBM cells but not primary endothelia and terminally differentiated neurons. Upon infection, ZIKV-LAV mediated GBM cell death via apoptosis and pyroptosis. This is the first in-depth molecular dissection of how oncolytic ZIKV infects and induces death in tumour cells.

Evidence of Zika Virus Reinfection by Genome Diversity and Antibody Response Analysis, Brazil.

We generated 238 Zika virus (ZIKV) genomes from 135 persons in Brazil who had samples collected over 1 year to evaluate virus persistence. Phylogenetic inference clustered the genomes together with previously reported ZIKV strains from northern Brazil, showing that ZIKV has been remained relatively stable over time. Temporal phylogenetic analysis revealed limited within-host diversity among most ZIKV-persistent infected associated samples. However, we detected unusual virus temporal diversity from >5 persons, uncovering the existence of divergent genomes within the same patient. All those patients showed an increase in neutralizing antibody levels, followed by a decline at the convalescent phase of ZIKV infection. Of interest, in 3 of those patients, titers of neutralizing antibodies increased again after 6 months of ZIKV infection, concomitantly with real-time reverse transcription PCR re-positivity, supporting ZIKV reinfection events. Altogether, our findings provide evidence for the existence of ZIKV reinfection events.

Genetically modified ZIKA virus as a microRNA-sensitive oncolytic virus against central nervous system tumors

Here we introduce a first-in-class microRNA-sensitive oncolytic Zika virus (ZIKV) for virotherapy application against central nervous system (CNS) tumors. The described methodology produced two synthetic modified ZIKV strains that are safe in normal cells, including neural stem cells, while preserving brain tropism and oncolytic effects in tumor cells. The microRNA-sensitive ZIKV introduces genetic modifications in two different virus sites: firstly, in the established 3’UTR region, and secondly, in the ZIKV protein coding sequence, demonstrating for the first time that the miRNA inhibition systems can be functional outside the UTR RNA sites. The total tumor remission in mice bearing human CNS tumors, including metastatic tumor growth, after intraventricular and systemic modified ZIKV administration, confirms the promise of this virotherapy as a novel agent against brain tumors - highly deadly diseases in urgent need of effective advanced therapies.

Discovery and structure-activity relationship study of novel isoxazole-based small molecules targeting Zika virus infections.

The Zika virus (ZIKV), a significant public health threat, is transmitted by Aedes aegypti mosquitoes and is associated with severe neurological disorders, particularly in newborns. Currently, there are no approved vaccines or specific therapeutics for ZIKV. Our study focuses on the identification and optimization of isoxazole-based small molecules, specifically through the structural modification of KR-26827, to combat ZIKV infections. Among the synthesized derivatives, 7l emerged as the most promising candidate, showing potent antiviral activity against ZIKV strains and an improved safety profile in vitro. This research underlines the potential of 7l for further development as a ZIKV therapeutic agent.

Zika Virus Infection Alters the Circadian Clock Expression in Human Neuronal Monolayer and Neurosphere Cultures.

Rhythmic regulations are virtually described in all physiological processes, including central nervous system development and immunologic responses. Zika virus (ZIKV), a neurotropic arbovirus, has been recently linked to a series of birth defects and neurodevelopmental disorders. Given the well-characterized role of the intrinsic cellular circadian clock within neurogenesis, cellular metabolism, migration, and differentiation among other processes, this study aimed to characterize the influence of ZIKV infection in the circadian clock expression in human neuronal cells. For this, in vitro models of human-induced neuroprogenitor cells (hiNPCs) and neuroblastoma cell line SH-SY5Y, cultured as monolayer and neurospheres, were infected by ZIKV, followed by RNA-Seq and RT-qPCR investigation, respectively. Targeted circadian clock components presented mRNA oscillations only after exogenous synchronizing stimuli (Forskolin) in SH-SY5Y monolayer culture. Interestingly, when these cells were grown as 3D-arranged neurospheres, an intrinsic oscillatory expression pattern was observed for some core clock components without any exogenous stimulation. The ZIKV infection significantly disturbed the mRNA expression pattern of core clock components in both neuroblastoma cell culture models, which was also observed in hiNPCs infected with different strains of ZIKV. The ZIKV-mediated desynchronization of the circadian clock expression in human cells might further contribute to the virus impairment of neuronal metabolism and function observed in adults and ZIKV-induced congenital syndrome. In vitro models of Zika virus (ZIKV) neuronal infection. Human neuroprogenitor cells were cultured as monolayer and neurospheres and infected by ZIKV. Monolayer-cultured cells received forskolin (FSK) as a coupling factor for the circadian clock rhythmicity, while 3D-arranged neurospheres showed an intrinsic oscillatory pattern in the circadian clock expression. The ZIKV infection affected the mRNA expression pattern of core clock components in both cell culture models. The ZIKV-mediated desynchronization of the circadian clock machinery might contribute to the impairment of neuronal metabolism and function observed in both adults (e.g., Guillain-Barré syndrome) and ZIKV-induced congenital syndrome (microcephaly). The graphical abstract has beencreated with Canva at the canva.com website.

Dengue and Zika RNA-RNA interactomes reveal pro- and anti-viral RNA in human cells

BackgroundIdentifying host factors is key to understanding RNA virus pathogenicity. Besides proteins, RNAs can interact with virus genomes to impact replication.ResultsHere, we use proximity ligation sequencing to identify virus-host RNA interactions for four strains of Zika virus (ZIKV) and one strain of dengue virus (DENV-1) in human cells. We find hundreds of coding and non-coding RNAs that bind to DENV and ZIKV viruses. Host RNAs tend to bind to single-stranded regions along the virus genomes according to hybridization energetics. Compared to SARS-CoV-2 interactors, ZIKV-interacting host RNAs tend to be downregulated upon virus infection. Knockdown of several short non-coding RNAs, including miR19a-3p, and 7SK RNA results in a decrease in viral replication, suggesting that they act as virus-permissive factors. In addition, the 3′UTR of DYNLT1 mRNA acts as a virus-restrictive factor by binding to the conserved dumbbell region on DENV and ZIKV 3′UTR to decrease virus replication. We also identify a conserved set of host RNAs that interacts with DENV, ZIKV, and SARS-CoV-2, suggesting that these RNAs are broadly important for RNA virus infection.ConclusionsThis study demonstrates that host RNAs can impact virus replication in permissive and restrictive ways, expanding our understanding of host factors and RNA-based gene regulation during viral pathogenesis.

Molecular epidemiology, clinical analysis, and genetic characterization of Zika virus infections in Thailand (2020–2023)

To investigate the clinical and molecular characteristics and evolution of the Zika virus (ZIKV) in Thailand from March 2020 to March 2023. In all, 751 serum samples from hospitalized patients in Bangkok and the surrounding areas were screened for ZIKV using real-time RT-PCR. Demographic data and clinical variables were evaluated. Phylogenetic and molecular clock analysis determined the genetic relationships among the ZIKV strains, emergence timing, and their molecular characteristics. Among the 90 confirmed ZIKV cases, there were no significant differences in infection prevalence when comparing age groups and sexes. Rash was strongly associated with ZIKV infection. Our ZIKV Thai isolates were categorized into two distinct clades: one was related to strains from Myanmar, Vietnam, Oceania, and various countries in the Americas, and the other was closely related to previously circulating strains in Thailand, one of which shared a close relation to a neurovirulent ZIKV strain from Cambodia. Moreover, ZIKV Thai strains could be further classified into multiple sub-clades, each exhibiting specific mutations suggesting the genetic diversity among the circulating strains of ZIKV in Thailand. Understanding ZIKV epidemiology and genetic diversity is crucial for tracking the virus's evolution and adapting prevention and control strategies.

Integrated re-analysis of transcriptomic and proteomic datasets reveals potential mechanisms for Zika viral-based oncolytic therapy in neuroblastoma

Background Paediatric neuroblastoma and brain tumours account for a third of all childhood cancer-related mortality. High-risk neuroblastoma is highly aggressive and survival is poor despite intensive multi-modal therapies with significant toxicity. Novel therapies are desperately needed. The Zika virus (ZIKV) can access the nervous system and there is growing interest in employing ZIKV as a potential therapy against paediatric nervous system tumours, including neuroblastoma. Methods Here, we perform extensive data mining, integration and re-analysis of ZIKV infection datasets to highlight molecular mechanisms that may govern the oncolytic response in neuroblastoma cells. We collate infection data of multiple neuroblastoma cell lines by different ZIKV strains from a body of published literature to inform the susceptibility of neuroblastoma to the ZIKV oncolytic response. Integrating published transcriptomics, interaction proteomics, dependency factor and compound datasets we propose the involvement of multiple host systems during ZIKV infection. Results Through data mining of published literature, we observed most paediatric neuroblastoma cell lines to be highly susceptible to ZIKV infection and propose the PRVABC59 ZIKV strain to be the most promising candidate for neuroblastoma oncolytic virotherapy. ZIKV induces TNF signalling, lipid metabolism, the Unfolded Protein Response (UPR), and downregulates cell cycle and DNA replication processes. ZIKV infection is dependent on sterol regulatory element binding protein (SREBP)-regulated lipid metabolism and three protein complexes; V-ATPase, ER Membrane Protein Complex (EMC) and mammalian translocon. We propose ZIKV non-structural protein 4B (NS4B) as a likely mediator of ZIKVs interaction with IRE1-mediated UPR, lipid metabolism and mammalian translocon. Conclusions Our work provides a significant understanding of ZIKV infection in neuroblastoma cells, which will facilitate the progression of ZIKV-based oncolytic virotherapy through pre-clinical research and clinical trials.