small molecules

2026-08-06 | Darunavir and Fosamprenavir Inhibit Zika Virus Replication via Dual Targeting of the Envelope Protein and NS2B-NS3 Protease.

Zika virus (ZIKV) remains a significant global health concern, underscoring the need for effective antiviral agents. In this study, we evaluated the antiviral activity and mechanisms of the HIV protease inhibitors darunavir (DRV), fosamprenavir (FPV), and amprenavir (APV) against ZIKV. DRV and FPV, but not APV, exhibited potent antiviral activity in BHK-21 and TE-671 cells, as demonstrated by reduced cytopathic effects and decreased viral protein expression. Both compounds inhibited ZIKV infectivity and viral yield with submicromolar EC50 values. Mechanistic analyses using time-of-addition and temperature-shift assays revealed that DRV and FPV act at multiple stages of the viral life cycle, including attachment, entry, and post-entry processes. Molecular docking and mutagenesis studies identified the β-octyl glucoside (β-OG) binding pocket within domain II of the ZIKV envelope (E) protein as a critical target, with Lys209 and Asp278 serving as key interaction residues. Disruption of these residues significantly reduced compound efficacy, confirming their functional importance in viral attachment inhibition. In addition, both DRV and FPV directly inhibited ZIKV NS2B-NS3 protease activity, with NS2B Asp83 identified as a key determinant for drug binding. In contrast, neither compound significantly affected NS5 RNA-dependent RNA polymerase activity. In a suckling mouse model, both DRV and FPV reduced viral loads in brain tissues in a dose-dependent manner, with DRV showing superior efficacy at lower doses. Collectively, these findings demonstrate that DRV and FPV exert potent anti-ZIKV activity through dual targeting of viral entry and protease function, highlighting their potential as repurposed therapeutics for ZIKV infection.

Open article ↗

2026-08-06 | Zika Virus Induces Progressive Morphological and Fibrotic Alterations in the Submandibular-Sublingual Salivary Complex of Immunosuppressed Mice.

To perform a morphological, histochemical, morphometric, and fractal analysis of the submandibular-sublingual salivary complex of immunosuppressed male Balb/c mice experimentally infected with Zika virus (ZIKV), aiming to characterize infection-related structural alterations. A total of 110 male Balb/c mice were immunosuppressed with dexamethasone and inoculated intraperitoneally with ZIKV. Animals were allocated into control and infected groups and euthanized at 14, 21, 28, 35, and 42 days post-infection (dpi). Body weight, salivary gland weight, and organosomatic index were assessed. The glands were processed for histological, histochemical, morphometric, and fractal analyses. Parameters evaluated included collagen deposition, acinar and ductal morphology, epithelial height, lumen area, fractal dimension, and lacunarity. Data were analyzed using the Kruskal-Wallis test with Dunn's post hoc (p < 0.05). ZIKV-infected mice showed transient body weight loss and increased glandular weight and organosomatic index at specific time points. Histopathological changes included ductal tortuosity, vacuolization, increased connective tissue, and higher cellularity. A progressive increase in collagen deposition was observed, indicating fibrosis in both serous and mucous acini, especially after 21 dpi. Morphometric and fractal analyses revealed marked glandular remodeling and increased structural complexity. These findings demonstrate that ZIKV infection induces significant morphological and fibrotic alterations in salivary glands.

Open article ↗

2026-07-28 | CD39 restrains ATP—P2X7-driven inflammatory cell death and neuroinflammation during neonatal Zika virus infection 2333356

Abstract Introduction Zika virus (ZIKV) can cause congenital Zika syndrome (CZS), marked by neuroinflammation and neurodevelopmental damage. Viral infection promotes extracellular ATP (eATP) release, acting as an alarmin that amplifies inflammation via purinergic receptors such as P2X7. CD39 enzyme (ENTPD1) hydrolyzes eATP and may restrain P2X7-dependent inflammatory cell death, but its role in neonatal ZIKV infection remains unclear. Methods THP-1-derived macrophages were stimulated with ZIKV or ZIKV envelope protein (ZIKV-E). Inflammatory readouts and eATP release were assessed, including evaluations with soluble apyrase or Axl-antagonist bemcentinib (R428). In vivo, WT and CD39⁻/⁻ pups were inoculated with ZIKV at postnatal day 3; brains were collected 12 days post-infection for molecular and histological analyses. Key pathways were also tested in P2X7⁻/⁻ mice. Results ZIKV-E increased eATP release and inflammatory responses, increased LDH release with elevated IL-1β/IL-6 and caspase-1/GSDMD-associated pyroptotic signaling; partially attenuated by soluble apyrase. R428 reduced ZIKV-E-induced eATP release, supporting upstream TAM/AXL involvement in purinergic activation. In neonatal brains, ZIKV upregulated CD39 transcripts and CD39 deficiency worsened motor performance and enhanced glial reactivity. CD39⁻/⁻ infection increased ZBP1 and apoptotic/pyroptotic markers (caspase-8, caspase-3, caspase-1, GSDMD), with enhanced association of ZBP1/caspase-3 with glial markers. CD39 deficiency enhanced IFN-β/STAT1 signaling. Conversely, P2X7 deficiency attenuated ZIKV-induced activation of apoptosis/pyroptosis markers, counterbalancing the CD39⁻/⁻ phenotype. Conclusion Our data identify CD39 as an upstream brake on eATP signaling that limits P2X7-linked inflammatory cell death and neuroinflammation during neonatal ZIKV infection, while shaping antiviral IFN responses. Targeting the CD39—P2X7 axis may provide therapeutic opportunities to mitigate neuroinflammatory damage in neurotropic viral infections. Funding Source FAPERJ; CAPES; CNPq; Instituto Nacional Saúde Cerebral (INSC) Topic Categories Viral Immunology (VIR)

Open article ↗

2026-07-24 | Host protein cleavage by Dengue and Zika virus NS3 proteases: from substrate identification to potential biological consequences.

Dengue virus (DENV) and Zika virus (ZIKV) are medically important orthoflaviviruses that utilize the multifunctional NS3 protease, in complex with its cofactor NS2B, for viral replication and host modulation. Here, we summarize current knowledge of host proteins targeted by NS3 proteases and discuss recent advances in proteomic and computational approaches for identifying these substrates. We further discuss evidence showing that NS2B3-mediated cleavage alters innate immune signaling, autophagy, protein translation, and cytoskeletal dynamics. In addition, we compare the host substrate specificities of DENV and ZIKV proteases, emphasizing both shared mechanisms and virus-specific differences that may contribute to their distinct disease manifestations. A deeper understanding of NS3-mediated host protein cleavage will provide critical insights into orthoflavivirus biology and further establish NS3 as a promising target for antiviral intervention.

Open article ↗

2026-07-17 | Exploitation of host U2AF1 and U2AF2 splicing factors facilitates mosquito-borne orthoflavivirus infection across species.

To identify novel host factors essential for orthoflavivirus replication, we performed proteomic profiling of endoplasmic reticulum fractions isolated from cells infected with Dengue virus or Zika virus (ZIKV). Among the enriched proteins, the splicing factor U2AF2 and its heterodimeric partner U2AF1 were found to be critical for efficient viral infection, functioning at the viral protein synthesis stage. The arginine/serine-rich (RS) domain and the first zinc knuckle (Zn1) of U2AF1, as well as nearly all domains except the RS domain of U2AF2, were essential for their proviral function. Disruption of the U2AF1-U2AF2 interaction potently suppressed ZIKV infection. U2AF1 and U2AF2 partially localize to the cytoplasm, and notably, the cytoplasmic U2AF2 was predominantly a truncated form that was sufficient to support viral replication. Both U2AF1 and U2AF2 bind to viral RNA, with U2AF1 binding being dependent on U2AF2. Interestingly, trans-complementation of the Aedes aegypti homolog u2af38 into U2AF1-knockout cells restored ZIKV replication, whereas expressing u2af50 in U2AF2-knockdown cells did not. However, knockdown of either u2af38 or u2af50 significantly inhibited the flavivirus replication in mosquitoes. Together, these findings reveal that flaviviruses co-opt host splicing factors in both human cells and mosquitoes, underscoring a conserved cross-species mechanism of viral exploitation.

Open article ↗

vaccines

2026-07-13 | Mouse models of Zika virus infection-induced placenta and fetal brain damage.

Zika virus (ZIKV) infection during pregnancy is associated with the development of Congenital Zika syndrome. The ZIKV epidemic in 2015 in South America exhibited an increased incidence of microcephaly cases in infants born to mothers who were infected during pregnancy, and infection in adults led to Guillain-Barré Syndrome. A growing body of literature demonstrates that the vertical transmission of ZIKV results in placental infection and injury. Further, ZIKV is transmitted to the fetus, specifically inducing apoptosis in neuronal progenitor cells, resulting in the development of microcephaly. This review summarizes recent advances in ZIKV infection, cell death, immune activation, and protective strategies in various mouse models. Specifically, we have reviewed recent studies on placental and fetal brain/head infections in mouse models, namely anti-IFNAR1 antibody-treated wild-type mice, Ifnar-deficient mice, Stat2-deficient mice, and humanized STAT2 knock-in mice. We also discussed the role of ZIKV infection-induced cell death, inflammation, interferon response, and associated immune-related outcomes in the placenta and fetal brain/head. In addition, we have reviewed recent advances in the development of vaccine candidates and potential therapeutic agents that protect against ZIKV-induced placental and fetal brain damage in preclinical models. In summary, our review of literature highlights key pathogenic mechanisms that drive ZIKV-induced placental and fetal brain/head injury, and protective strategies against ZIKV infection.

Open article ↗

2026-05-13 | Strategies to enhance DNA vaccine efficacy against emerging arboviruses: lessons from ZIKA and Chikungunya viruses.

The mosquito-borne arboviruses Zika and Chikungunya pose serious health threats worldwide, often co-circulating and causing co-infections in Aedes endemic regions. While no licensed vaccine is currently available for Zika virus (ZIKV), recent progress has led to the approval of vaccines for Chikungunya virus (CHIKV) in few countries, highlighting the need for improved vaccine strategies. Zika virus (ZIKV) presents unique challenges, including its neurotropism, association with congenital abnormalities, and potential for sexual and vertical transmission, whereas Chikungunya virus (CHIKV) is characterized by viral persistence in joint-associated tissues, leading to chronic inflammatory manifestations such as long-term arthralgia, along with comparatively limited clinical trial data for vaccine candidates. DNA vaccines offer a promising platform since they are safe and easy to produce; but their immunogenicity in humans is limited. The rational use of adjuvants and optimized delivery systems is important for enhancing DNA vaccine efficacy. This review discusses current adjuvant classes, including Toll-like receptor (TLR) agonists, molecular adjuvants, and classical adjuvants, focusing on their mechanisms to enhance immune cell activation and adaptive immunity. We summarize preclinical and clinical findings on DNA vaccines for ZIKV and CHIKV, highlighting the synergy of adjuvants with different delivery technologies and discuss the rationale for multivalent DNA vaccine strategies to address co-circulating arboviral infections. Finally, we have identified research gaps and suggested a translational roadmap to accelerate the development of effective DNA vaccines against these emerging arboviruses.

Open article ↗

2026-04-17 | Effects of candidate vaccines against Zika virus infection: A systematic review of the clinical trials.

The 2015-2016 Zika virus (ZIKV) pandemic revealed a pathogenic potential, including Guillain-Barré syndrome and Congenital Zika Syndrome (CZS). Despite the decline in incidence, the potential for future circulation and the absence of specific antivirals underscore continued scientific interest in prophylactic vaccine development. To synthesize evidence from clinical trials regarding the safety and preliminary immunogenicity of current ZIKV vaccine candidates. This systematic review followed PRISMA guidelines (CRD420251056463). Searches were performed in MEDLINE, Embase, Web of Science, SciELO, and LILACS for clinical trials published between 2015 and 2025. Risk of bias was assessed using the Cochrane RoB 2 tool. Ten Phase 1 clinical trials were included, evaluating four platforms: inactivated virus (ZPIV, TAK-426, VLA1601), DNA (GLS-5700, VRC5283), mRNA (mRNA-1325, mRNA-1893), and viral vector (Ad26.ZIKV.001). All candidates demonstrated acceptable safety profiles, with predominantly mild-to-moderate and transient adverse events (e.g., injection site pain, fatigue, and headache); no vaccine-related serious adverse events were reported. Most platforms induced robust neutralizing antibody responses. Specifically, TAK-426 showed immune persistence for up to two years, while mRNA-1893 maintained responses for 13 months. The viral vector vaccine (Ad26.ZIKV.001) achieved 100% seroconversion with a single dose. Previous orthoflavivirus exposure did not significantly hinder vaccine-induced immunogenicity. Most studies presented a low risk of bias. ZIKV vaccine candidates across diverse technological platforms are safe and highly immunogenic. The evidence of long-term durability and the success of single-dose or mRNA regimens support the progression of the most promising candidates to Phase 2/3 trials.

Open article ↗

2026-04-01 | Integrative immunogenomic strategy for designing a multi-epitope vaccine against Zika and Dengue viruses.

Two of the most prevalent illnesses spread by mosquitoes are the Dengue virus (DENV) and the Zika virus (ZIKV), both of which belong to the Flaviviridae family. Co-infection with ZIKV and DENV has been reported worldwide, sometimes with dire consequences. Developing a single vaccine capable of protecting against both pathogens would therefore be highly beneficial. In this research, an in-silico immunology strategy was employed to construct a multi-epitope, multi-pathogen vaccine targeting both viruses. Considering that DENV and ZIKV share the same mosquito vector, Aedes aegypti, and that its salivary proteins can facilitate viral infection, eleven CTL epitopes, five B-cell antigenic determinants, and twelve HTL epitopes were chosen for the final vaccine. Our DENV and ZIKV vaccine have 567 amino acids and molecular mass is 58603.84 amu. An in-silico 3D modelling process and a structural explanation of the model followed docking and dynamics simulations utilizing human TLR7 and TLR5 with docking scores of -392.81 and − 370.88, respectively. The immune reaction simulation suggests that the suggested vaccination may cause a significant immune response that can protect against both DENV and ZIKV.

Open article ↗

2025-12-23 | Rational design of flavivirus E protein vaccine optimizes immunogenicity and mitigates antibody dependent enhancement risk.

Flaviviruses are a family of related viruses that cause substantial global morbidity and mortality. Vaccination against one flavivirus can sometimes exacerbate disease caused by related viruses through antibody-dependent enhancement (ADE) or interfere with the efficacy of subsequent vaccines. To address this challenge, we develop a vaccine strategy by introducing G5C/G102C mutations into the flavivirus envelope (E) glycoprotein. These mutations promote E dimerization through the formation of an inter-chain disulfide bond that conceals the immunodominant and ADE-prone fusion loop epitope (FLE). We validate this design on E proteins from multiple flaviviruses through biochemical, antigenic, and structural analyses. The resulting vaccine candidate, CC_FLE sE, derived from the Zika virus (ZIKV) and formulated with an advanced supramolecular adjuvant, provides significant protection in female mice challenged with ZIKV and prevents ADE caused by a related flavivirus, Dengue virus. In genetically modified mice expressing diverse human immunoglobulin loci, ZIKV CC_FLE sE induces robust neutralizing antibody responses targeting key ZIKV E protein epitopes, including the E-dimer-dependent epitope (EDE), indicating that ZIKV CC_FLE sE can elicit protective antibody responses within the human naïve B cell repertoire. Therefore, CC_FLE sE represents a promising strategy for developing flavivirus vaccines that minimize ADE risk while maintaining high protective efficacy.

Open article ↗

antibodies

2026-08-14 | Activation and Inhibition of Autophagy and the Lysosome: Potential Therapeutic Avenues for Prenatal Zika Virus Infection

Zika virus (ZIKV), a mosquito-borne flavivirus, has been found in 87 countries and territories. Global outbreaks peaked in 2016. Prenatal Zika virus infection was found to be associated with microcephaly, arthrogryposis, intracranial calcifications, fetal growth restriction, and fetal demise. The most severely affected children were diagnosed with congenital Zika syndrome, which impacts thousands worldwide. With no approved treatment or preventative measures for Zika virus, future viral outbreaks have the potential to cause epidemic levels of prenatal brain injury, as seen over the past 70 years. Therefore, there is a great need for a reliable and clinically translational experimental system that mimics the human condition of prenatal Zika virus infection. To this end, we developed a novel, humanized, immunocompetent preclinical system of virally induced brain injury from prenatal Zika virus infection, which ranges from mild to severe. Here, we describe the extent to which this system mirrors the human phenotypic spectrum. Using our thorough preclinical system, we find that prenatal Zika virus infection of mice impacts survival rate, anthropometric measurements, tissue formation, and neurological outcomes, all of which are typically affected by prenatal infection. Current and future applications include the identification of genetic or environmental modifiers of brain injury, molecular or mechanistic studies of pathogenesis, and preclinical evaluation of future therapies.

Open article ↗

2026-08-07 | Generation and characterization of an anti ITGB4 monoclonal antibody that blocks Zika virus entry.

Zika virus (ZIKV) causes congenital disease and neurological complications, yet no approved vaccines or antivirals are available. Integrin β4 (ITGB4) has been identified as an entry receptor for ZIKV. Recombinant human ITGB4 ectodomain was expressed using a baculovirus-insect cell system and used to immunize BALB/c mice. Hybridoma screening identified monoclonal antibody 7C3. Binding affinity to ITGB4 was determined by biolayer interferometry. Epitope relationships between 7C3 and the previously reported anti-ITGB4 antibody 13H10 were assessed by competitive binding assay. Antiviral activity was evaluated in four cell lines by RT-qPCR quantification of cell-associated ZIKV RNA after antibody pretreatment and viral challenge. 7C3 bound ITGB4 with picomolar affinity (KD=30.9 pM) and high specificity. Competitive binding showed that 7C3 and 13H10 (KD=7.98 pM) recognize non-overlapping epitopes on ITGB4. Pretreatment with 7C3 significantly reduced cell-associated ZIKV RNA in all four cell lines compared with PBS and isotype controls. A second, independently generated anti-ITGB4 antibody with picomolar affinity can robustly block ZIKV entry across multiple cell types, including SY5Y neuroblastoma cells relevant to congenital neuropathology. The non-overlapping epitopes of 7C3 and 13H10 suggest potential for combination strategies to enhance ITGB4 blockade. High germline identity of the 7C3 variable regions (VH=94.46%, VL=95.82%) supports future humanization. These findings establish 7C3 as a host-directed antiviral candidate and provide a basis for ITGB4-targeting approaches against congenital ZIKV disease.

Open article ↗

2026-05-21 | E-protein variability in Zika virus strains: A possible new O-glycosylation site and its implications.

Background and objectives Zika virus (ZIKV) is a flavivirus transmitted by the bite of infected Aedes mosquito. In 2015-16, Brazil reported cases of ZIKV virus infection followed by Guillain-Barre syndrome and congenital birth defects. India has reported ZIKV virus infections sporadically since 2016, without adverse events. This prompted us to conduct this in-silico investigation and identify reasons for this variation. The objective was to study ZIKV envelope protein (E-protein) to identify possible mutations and their potential role in virus entry into the host cell. Methods Using multiple sequence alignments, we compared the genomic sequences from eleven ZIKV strains with maximum genomic data available in the NCBI database, followed by phylogenetic analysis. ZIKV E-protein structures with mutations were generated using AlphaFold and used for molecular dynamic simulation, followed by protein 3D structure and residues interaction analysis. Results We identified 2 major ZIKV clades - ZIKV Senegal strain (African lineage, Accession No. MF510857, 1984) is an ancestral strain representing one clade, while the remaining strains belong to the second major clade, with the Indian strain being closest to the Senegal strain genomically. The Senegal strain also has a significant mutation at residue no. 120 of the E-protein (Alanine to Threonine), which is absent in other strains. Interpretation and conclusions We found a mutation in the ZIKV Senegal strain at residue no. 120 (Alanine Threonine), here Threonine is interacting with Serine residue at position 64. This interaction is known for post-translational O-glycosylation of E-protein, which may reduce the efficacy of envelope-based therapies. To the best of our knowledge, this is the first report of a putative O-glycosylation site on the E-protein of a ZIKV strain, which is an important therapeutic target, and our finding needs further in vitro validation.

Open article ↗

2026-05-04 | Dual role of Japanese encephalitis virus fusion loop peptide antibodies in Zika virus infection.

Zika virus (ZIKV) is a key member of the Flavivirus genus that has emerged as a major global public health concern. The fusion loop region (residues 98-110), located within domain II of the envelope protein, is highly conserved among flaviviruses, including ZIKV and Japanese encephalitis virus (JEV). However, the functional consequences of such conservation for cross-reactive immunity remains unclear. Here, we integrated bioinformatic analyses, functional assays in vitro and mouse models in vivo to systematically determine the effects of antibodies directed against the JEV fusion loop (FL) region on ZIKV infection. Sequence alignment and structural analysis revealed complete amino acid identity and almost identical three-dimensional conformations between the FL regions of the two viruses, providing a molecular basis for cross-reactivity. Antisera generated against the JEV FL region recognized ZIKV particles and displayed concentration-dependent bidirectional effects. Increased and decreased antibody levels respectively neutralized viral entry and replication, and facilitated infection via antibody-dependent enhancement (ADE). These effects were confirmed in vivo, in which high and low antibody doses reduced tissue pathology and improved survival, and increased viremia and exacerbated inflammatory responses, respectively. These findings highlight the importance of antibody concentration in determining whether cross-reactive responses to conserved structural elements engender neutralization or enhancement response. Our findings provide experimental evidence for assessing ZIKV susceptibility in JEV-vaccinated populations and offer structural insights for designing flavivirus vaccines that maximize protection while minimizing ADE risk. These findings further highlight potential pathogenic and clinical considerations for optimizing vaccine formulations to reduce cross-reactive enhancement risks.

Open article ↗

2026-03-10 | SLC3A2 promotes early-stage of Zika virus infection in human placental cells and astrocytes

Abstract Background: Zika virus (ZIKV) has been associated with neonatal microcephaly or atypical Guillain-Barré syndrome in adults since 2016. However, despite considerable progress in understanding the biology and pathogenesis of ZIKV infection, little is known about its entry factors. This study aimed to identify host-cell proteins essential for ZIKV entry enriched by labeled viral envelope particles. The identification of solute carrier family 3 member 2 (SLC3A2) (CD98 heavy chain) through this approach highlights its potential as a novel target for therapeutic intervention against ZIKV. Methods: Gene editing via CRISPR-Cas9 and classical virological experiments were performed to identify SLC3A2 functions in ZIKV entry and infection processes. Immunofluorescence, quantitative real-time PCR (RT-qPCR), and western blotting technologies were further used to detect viral proteins and genomes. Besides, coimmunoprecipitation and protein/antibody blocking assay were also conducted to identify direct interactions between SLC3A2 and the ZIKV envelope protein. Results: Several human membrane proteins were overexpressed in HEK293 T cells, but only SLC3A2 could significantly promote ZIKV entry into host cells by two- to three- fold compared with the control. During authentic ZIKV infection, the genetic ablation of SLC3A2 in SLC3A2-KO1 JEG-3 cells reduced the viral infection rate to 59.00% ± 5.10% of the wild-type level (100.00% ± 4.97%) ( P < 0.001), but its overexpression increased the susceptibility of human placenta- and brain-derived cell lines to the virus. SLC3A2 overexpression increased attached ZIKV levels to 3.4-fold of the control (3.423 ± 0.715 vs . 1.000 ± 0.897, P < 0.001) and internalized ZIKV levels to 1.7-fold of the control (3.782 ± 0.512 vs . 2.293 ± 0.272, P = 0.013) due to direct interaction with the ZIKV envelope protein in U-251MG cells. Our data further showed the close association of SLC3A2 with the ZIKV envelope protein via its extracellular domain during authentic viral infection. Notably, SLC3A2 ectodomain decoys and blocking antibodies markedly reduced ZIKV infection rather than affecting influenza A virus infection. Conclusion: SLC3A2 promotes ZIKV infection in placenta- or brain-derived cells by directly interacting with the ZIKV envelope protein and improving virus entry. SLC3A2 may be implicated in early-phase ZIKV infection as its entry factor, thereby identifying a potential therapeutic target and a basis for formulating antiviral strategies against ZIKV.

Open article ↗

proteins

2026-08-07 | Antiviral efficacy of Trappin-2/Elafin against Zika virus in the human keratinocyte HaCaT cell line.

Zika virus (ZIKV) is primarily transmitted through mosquito bites, and the skin acts as the initial site of viral entry into the host. Consequently, resident skin cells are among the first targets of infection. The epidermis, mainly composed of keratinocytes, can mount an antiviral response against arboviruses through the production of interferons, interferon-stimulated genes, cytokines, and antimicrobial peptides (AMPs), including the Trappin-2/Elafin (Tr2/E) peptide. However, the antiviral activity of Tr2/E during ZIKV infection remains poorly understood, therefore, this study aimed to investigate the antiviral activity of Tr2/E in human keratinocytes during ZIKV infection. In this study, we evaluated the permissiveness of the human keratinocyte cell line HaCaT to infection with a Mexican isolate of ZIKV and observed that these cells support productive viral infection. We then assessed whether ZIKV infection induces endogenous expression of Tr2/E. Tr2/E transcripts were detected in infected cells and showed increased expression over time post-infection, which correlated with the presence of its corresponding protein. Furthermore, we evaluated the antiviral potential of this peptide through exogenous treatment of infected keratinocytes. A significant reduction in ZIKV infection following Tr2/E treatment was observed. Collectively, these findings provide additional insight into the involvement of AMPs in the antiviral response to ZIKV infection and highlight Tr2/E as a potential antiviral factor.

Open article ↗

2026-06-09 | Human dermal fibroblast-derived factors from sequential DENV-2 and ZIKV coinfection drive dendritic cell maturation and antiviral responses.

Dengue virus (DENV) and Zika virus (ZIKV) are among the most prevalent mosquito-borne viruses worldwide. These viruses co-circulate in the same geographical regions and share the same mosquito vectors, enabling concurrent or sequential transmission to humans within a short period. During the early phase of arbovirus infection, skin-resident cells constitute the first line of defense following viral inoculation, yet the immunological events in the skin microenvironment during early DENV-ZIKV coinfection are not well understood. This study aimed to investigate the response of primary human dermal fibroblasts (HDFs) to DENV-ZIKV coinfection and to determine how these responses influence bystander immune cells within an in vitro. We demonstrated that sequential infection with DENV-2 followed by ZIKV significantly increased the expression of pro-inflammatory cytokines (IL-6, IL-8, IL-1β), leukocyte migration-associated chemokine (CXCL10), and antiviral mediators (IFN-β and IFN-λ) in HDFs. Primary monocyte-derived dendritic cells (moDCs) exposed to soluble mediators from sequentially coinfected HDFs exhibited greater activation marker expression compared with simultaneous coinfection or monoinfection conditions. Furthermore, these mediators conferred antiviral effects against both DENV-2 and ZIKV infection in treated moDCs. These findings highlight the important role of dermal fibroblasts in shaping adaptive immunity and limiting viral spread during DENV and ZIKV coinfection.

Open article ↗

2026-05-29 | ACSS2-mediated MYH9 crotonylation drives Zika virus-induced vascular smooth muscle cell phenotypic switching.

Zika virus (ZIKV) infection represents an emerging cause of cardiovascular pathology, yet the molecular mechanisms driving virus-induced vascular injury remain incompletely defined. This investigation identifies a crotonylation pathway underlying ZIKV-induced vascular disease. We demonstrate that ZIKV infection upregulates the metabolic regulator ACSS2, consequently elevating intracellular crotonyl-CoA levels. This metabolic shift drives lysine crotonylation of the cytoskeletal protein MYH9 at the critical K82 residue, triggering a pathological transition of vascular smooth muscle cells from contractile to synthetic phenotypes. This cellular reprogramming promotes aortic injury across multiple animal models, including northern pig-tailed macaques and A129 mice. Genetic ablation of ACSS2 substantially attenuated both the phenotypic switching and disease progression. Furthermore, we developed a targeted therapeutic peptide that effectively inhibits MYH9-K82 crotonylation and mitigates pathological vascular remodeling. These findings not only elucidate ACSS2-mediated protein crotonylation as a fundamental mechanism in ZIKV-induced vasculopathy but also present a promising precision therapeutic strategy for treating virus-induced proliferative vascular diseases.

Open article ↗

2026-03-31 | Breaking barriers and beyond: Mechanisms and pathological implications of Zika virus traversal across blood-tissue interfaces.

Blood-tissue barriers are specialized interfaces that safeguard organ homeostasis by restricting pathogen dissemination. Zika virus (ZIKV), an emerging flavivirus of global concern, exhibits an exceptional ability to breach multiple barriers-including the blood-brain, blood-placental, blood-testis, and blood-retinal barriers-enabling neuroinvasion, vertical and sexual transmission, and ocular disease. ZIKV employs diverse strategies to cross these barriers: receptor-mediated entry, disruption of tight junctions, and hijacking immune cells or extracellular vesicles as viral carriers. Adaptive mutations further refine tissue tropism and enhance barrier traversal efficiency. Insights from cell culture, organoid, animal, and ex vivo tissue models reveal not only the conserved and tissue-specific mechanisms of barrier penetration but also the downstream pathological consequences in the affected organs. Understanding how ZIKV breaches these interfaces and induces organ-specific pathology deepens our knowledge of host-pathogen interactions and provides a framework for designing barrier-protective and disease-mitigating strategies against ZIKV and other pathogens that breach blood-tissue barriers.

Open article ↗

2026-02-09 | Interferon lambda signaling to maternal dendritic cells protects against congenital Zika virus infection.

Interferon lambda (IFN-λ, type III IFN) mediates antiviral immunity at anatomic barriers, including the maternal-fetal interface. To investigate the effects of IFN-λ during congenital Zika virus (ZIKV) infection, we infected mice lacking the IFN-αβ receptor (Ifnar1 -/-) or both the IFN-αβ and IFN-λ receptors (Ifnar1 -/- Ifnlr1 -/-) at E9 and found that loss of maternal IFN-λ signaling resulted in greater transplacental transmission. We used HiPlex RNAscope on entire gravid uteruses and found that IFN-λ was expressed more proximal to the site of ZIKV infection in Ifnar1 -/- dams compared to Ifnar1 -/- Ifnlr1 -/- dams. We performed immunophenotyping of the placenta and uterus by flow cytometry and found a decrease in dendritic cells and NK cells in the uterus of Ifnar1 -/- Ifnlr1 -/- dams compared to Ifnar1 -/- dams, but NK cell depletion did not impact fetal infection. Using conditional knockout mice, we identified maternal dendritic cells as the key IFN-λ responsive cell type mediating protection against ZIKV congenital infection.

Open article ↗

other

2026-06-06 | Zika virus as an oncolytic therapy.

Glioblastoma (GBM) is a common, aggressive, primary brain tumor. New therapies are needed to improve outcomes in patients with this disease. One such approach which has shown preclinical promise is the use of genetically engineered Zika virus for oncolytic virotherapy. Zika virus is an enveloped, positive-sense, single-stranded RNA virus and is spread by mosquitoes of the Aedes genus. Most infections with Zika virus in adults are asymptomatic. However, primary infection with Zika virus early during pregnancy can cause fetal congenital defects. This phenomenon, termed congenital Zika syndrome, is thought to be the result of infection of fetal neural stem cells. The development of Zika virus as an oncolytic for GBM arose from the discovery that Zika virus infects and kills GBM stem cells. GBM stem cells have similarities to fetal neural stem cells and are a subpopulation of cells within the tumor that are refractory to treatment and likely drive tumor persistence and re-occurrence. In preclinical models of GBM, infection with Zika virus triggers immune-mediated clearance of orthotopically transplanted tumors and leads to development of immunological memory. The propensity of Zika virus to infect GBM stem cells along with limited systemic toxicities and transmissibility make Zika virus an ideal candidate for development as an oncolytic therapy.

Open article ↗

2026-05-21 | A CRISPR activation screen identifies SPART as a pan-orthoflavivirus restriction factor.

Orthoflaviviruses, including Zika (ZIKV), dengue, Japanese encephalitis, and West Nile viruses, cause diverse clinical syndromes and threaten human health. Identifying factors that inhibit orthoflavivirus infection could lead to antiviral countermeasures. Here, we conducted a genome-wide CRISPR activation screen and identified the host gene SPART (Spartin/SPG20) as a restriction factor against ZIKV and other orthoflaviviruses. SPART interacts with and disrupts the endosomal localization of Itchy E3-ubiquitin ligase (ITCH), which we determine ubiquitinates the ZIKV capsid, thereby triggering uncoating. Loss of SPART enhances ZIKV replication, an effect not observed in SPART-ITCH double knockout mutants. Maternal ZIKV infection of Spg20-/- mice results in heightened maternal and fetal viral loads and greater fetal abnormalities, whereas infection of Itch-/- mice yields opposite outcomes. Similar results were observed in these gene-edited mice upon infection with related orthoflaviviruses. Overall, this approach identified a broad orthoflavivirus restriction factor, providing a potential target against these emerging pathogenic viruses.

Open article ↗

2026-05-15 | MicroRNA-124-targeted recombinant Zika virus: a dual-functional and safe candidate for vaccination and oncolytic virotherapy.

Zika virus (ZIKV) remains a significant public health threat due to its pronounced neurotropism linked to Congenital Zika Syndrome (CZS). Paradoxically, the same neurotropism also provides a unique opportunity for exploiting ZIKV as an oncolytic agent against malignant brain tumors such as glioma. However, achieving precise control of ZIKV replication in specific cell types or tissues remains a major challenge. Here, we show that the brain-specific and enriched microRNA, miR-124, is highly expressed in neural progenitor cells (NPCs) and neurons, but minimally expressed in glioma stem cells (GSCs) and differentiated glioma stem cells (DGCs). Based on these observations, we engineered a recombinant ZIKV containing a miR-124 target sequence (miR-124T) inserted into the 3' untranslated region (UTR) of the viral genome, generating the virus designated ZIKV-miR124T. ZIKV-miR124T exhibited a significantly attenuated phenotype across multiple mouse models, including adult A129 mice, BALB/c neonates, and pregnant mice. Importantly, in an orthotopic glioma model, ZIKV-miR124T retained potent oncolytic activity while showing a markedly improved safety profile. Viral replication was strictly confined in the tumor region, with a ~1,000-fold reduction in viral load in non-tumoral brain regions compared to the well-established live-attenuated ZIKV (ZIKV-LAV). Furthermore, a single immunization with ZIKV-miR124T conferred effective protection against lethal ZIKV challenge and significantly reduced vertical transmission in pregnant mice. Collectively, our findings establish a strong proof of concept for a rational, miRNA-guided strategy to generate a next-generation ZIKV platform with dual potential as a safe live-attenuated vaccine and a precisely regulated oncolytic virus. This study presents a crucial advancement in controlling the safety and function of neurotropic viruses. We engineered a dual-purpose ZIKV, ZIKV-miR124T, which is regulated by the brain-specific microRNA, miR-124. This design forces the virus to strongly self-suppress in healthy neural tissue, solving a major safety concern for ZIKV-based therapies. ZIKV-miR124T is shown to be a potent oncolytic agent against malignant glioma while also serving as a highly effective, safe live-attenuated vaccine against ZIKV infection, reducing vertical transmission to the fetus. Our work provides a strong demonstration of utilizing microRNA regulation to achieve precise viral tropism and attenuation, offering a valuable, generalizable strategy for the development of safer and more effective viral therapies and vaccines against neurotropic pathogens.

Open article ↗

2026-04-01 | The Upregulation of Anti-apoptotic BIRC3 Expression Facilitates Zika Virus Infection

Objective: The aim of this study was to investigate the apoptotic gene expression profile and to identify the genes involved in apoptosis and ZIKV infection. Materials and Methods: SH-SY5Y cell line was infected with ZIKV at an MOI of 5. The cells were stained with Annexin V and propidium iodide to determine apoptosis. A real-time polymerase chain reaction array was employed to determine the apoptotic gene expression profile in a ZIKV-infected SH-SY5Y cell line. Western blot analysis was performed to confirm the expression of BIRC3 in both SH-SY5Y and A549 cell lines. Knockdown of the BIRC3 was done in ZIKV-infected A549 cell line using BIRC3 -specific siRNA. The ZIKV production was measured by focus-forming unit assay. Results: Apoptotic genes in both extrinsic and intrinsic pathways, such as TNF-α, TRAIL, FAS, CASP8, CASP9, and BIRC3, were found to be upregulated. The anti-apoptotic gene BIRC3 was selected and found to be upregulated at the protein level in both ZIKV-infected SH-SY5Y and ZIKV-infected A549 cell lines. Knockdown of the BIRC3 gene in ZIKV-infected A549 cell line decreased Zika virus NS1 protein expression and Zika virion production. Conclusion: The upregulation of anti-apoptotic BIRC3 expression facilitates Zika virus infection.

Open article ↗

2026-03-28 | Establishment of a Cell-Fusing Agent Virus Infection Model in Aedes albopictus and Its Impact on Vector Competence for Zika Virus.

The overuse of chemical insecticides highlights the urgent need for novel vector control strategies. Insect-specific viruses (ISVs), such as the cell-fusing agent virus (CFAV), have shown potential to block arbovirus transmission by inhibiting viral replication in mosquitoes. However, the effects of CFAV beyond its natural host, Aedes aegypti, remain largely unexplored. In this study, we established a CFAV infection model in Aedes albopictus, a major vector for Zika virus (ZIKV), via intrathoracic injection. Stable infection was achieved, with viral loads reaching up to 107 copies per mosquito by day 10 post-injection. Nevertheless, high post-injection mortality (median survival: 3 days) was observed, which we attribute primarily to mechanical injury. No evidence of vertical transmission of CFAV was detected in Ae. albopictus. Co-injection of CFAV and ZIKV did not significantly affect ZIKV replication in this species. In contrast, in Ae. aegypti pre-infected with CFAV followed by oral ZIKV challenge, CFAV significantly reduced ZIKV infection rates in the ovaries at day 4 and viral loads in salivary glands at day 10. These findings demonstrate that while CFAV can productively infect Ae. albopictus, it does not undergo vertical transmission in this species, and has no inhibitory effect on ZIKV under the co-infection conditions tested. This study underscores challenges associated with using single ISVs such as CFAV for arbovirus control and highlights the complex, bidirectional role of multiple ISV co-infections. While exploring multi-ISV combinations may offer a potential strategy to enhance antiviral efficacy, their net effect-whether suppression or enhancement of arboviruses-warrants careful investigation.

Open article ↗