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

BACKGROUND: Zika virus (ZIKV) is a single-stranded RNA flavivirus transmitted by mosquitoes. Its infection is associated with neurological complications such as neonatal microcephaly and adult Guillain-Barré syndrome, posing a serious threat to the health of people worldwide. Therefore, there is an urgent need to develop effective anti-ZIKV drugs. Atranorin is a lichen secondary metabolite with a wide range of biological activities, including anti-inflammatory, antibacterial and antioxidant, etc. However, the antiviral activity of atranorin and underlying mechanism has not been fully elucidated. PURPOSE: We aimed to determine the anti-ZIKV activity of atranorin in human glioma cell line SNB-19 and investigate the potential mechanism from the perspective of viral life cycle and the host cell functions. METHODS: We first established ZIKV-infected human glioma cells (SNB-19) model and used Western Blot, RT-qPCR, immunofluorescence, fluorescence-activated cell sorting (FACS) and plaque assay to evaluate the anti-ZIKV activity of atranorin. Then we assessed the regulation effect of atranorin on ZIKV induced IFN signal pathway activation by RT-qPCR. Afterward, we introduced time-of-addition assay, viral adsorption assay, viral internalization assay and transferrin uptake assay to define which step of ZIKV lifecycle is influenced by atranorin. Finally, we performed virus infectivity assay, molecular docking and thermal shift assay to uncover the target protein of atranorin on ZIKV. RESULTS: Our study showed that atranorin could protect SNB-19 cells from ZIKV infection, as evidenced by inhibited viral protein expression and progeny virus yield. Meanwhile, atranorin attenuated the activation of IFN signal pathway and downstream inflammatory response that induced by ZIKV infection. The results of time-of-addition assay indicated that atranorin acted primarily by disturbing the viral entry process. After ruling out the effect of atranorin on AXL receptor tyrosine kinase (AXL) dependent virus adsorption and clathrin-mediated endocytosis, we confirmed that atranorin directly targeted the viral envelope protein and lowered ZIKV infectivity by thermal shift assay and virus infectivity assay respectively. CONCLUSION: We found atranorin inhibits ZIKV infection in SNB-19 cells via targeting ZIKV envelope protein. Our study provided an experimental basis for the further development of atranorin and a reference for antiviral drug discovery from natural resources.

Identification of alpha-linolenic acid as a broad-spectrum antiviral against zika, dengue, herpes simplex, influenza virus and SARS-CoV-2 infection.

Zika virus (ZIKV) has garnered global attention due to its association with severe congenital defects including microcephaly. However, there are no licensed vaccines or drugs against ZIKV infection. Pregnant women have the greatest need for treatment, making drug safety crucial. Alpha-linolenic acid (ALA), a polyunsaturated ω-3 fatty acid, has been used as a health-care product and dietary supplement due to its potential medicinal properties. Here, we demonstrated that ALA inhibits ZIKV infection in cells without loss of cell viability. Time-of-addition assay revealed that ALA interrupts the binding, adsorption, and entry stages of ZIKV replication cycle. The mechanism is probably that ALA disrupts membrane integrity of the virions to release ZIKV RNA, inhibiting viral infectivity. Further examination revealed that ALA inhibited DENV-2, HSV-1, influenza virus and SARS-CoV-2 infection dose-dependently. ALA is a promising broad-spectrum antiviral agent.

Euphopias G - J, macrocyclic diterpenes with anti-zika virus activity from Euphorbia helioscopia L.

Four new diterpenoids (1-4) and sixteen known diterpenoids (5-20) were purified from the whole plant of Euphorbia helioscopia L. Compounds 1 and 2 were rhamofolane diterpenoids with a 5/7/6 tricyclic systems, compound 3 was a lathyranes diterpenoid, and compound 4 was a jathophanes diterpenoid. The isolated compounds were tested for their cytotoxicity and anti-Zika virus properties, and compounds 9 and 15 showed low cytotoxicity and strong anti-Zika virus properties with EC50 2.63 and 5.94 µM, respectively. Further, the inhibitory effects of compounds on protein levels were determined using Western blotting and immunofluorescence assays.

Anti-Zika Virus Activity and Isolation of Flavonoids from Ethanol Extracts of Curatella americana L. Leaves.

The ethnomedicinal plant Curatella americana L. (Dilleniaceae) is a common shrub in the Brazilian Cerrado, whose ethanolic extract showed significant in vitro anti-Zika virus activity by the MTT colorimetric method. Currently, there is no drug in clinical use specifically for the treatment of this virus; therefore, in this work, the antiviral and cytotoxic properties of the ethanolic extract, fractions, and compounds were evaluated. The ethanolic extract of the leaves showed no cytotoxicity for the human MRC-5 cell and was moderately cytotoxic for the Vero cell (CC50 161.5 ± 2.01 µg/mL). This extract inhibited the Zika virus multiplication cycle with an EC50 of 85.2 ± 1.65 µg/mL. This extract was fractionated using the liquid-liquid partition technique, and the ethyl acetate fraction showed significant activity against the Zika virus with an EC50 of 40.7 ± 2.33 µg/mL. From the ethyl acetate fraction, the flavonoids quercetin-3-O-hexosylgallate (1), quercetin-3-O-glucoside (2), and quercetin (5) were isolated, and in addition to these compounds, a mixture of quercetin-3-O-rhamnoside (3) and quercetin-3-O-arabinoside (4) was also obtained. The isolated compounds quercetin and quercetin-3-O-hexosylgallate inhibited the viral cytopathic effect at an EC50 of 18.6 ± 2.8 and 152.8 ± 2.0, respectively. Additionally, analyses by liquid chromatography coupled to a mass spectrometer allowed the identification of another 24 minor phenolic constituents present in the ethanolic extract and in the ethyl acetate fraction of this species.

Antiviral Effect of Stenocline ericoides DC. and Stenocline inuloides DC., Two Flavonoid-Rich Endemic Plants from Madagascar, against Dengue and Zika Viruses.

Dengue and Zika viruses are identified as the most medically important arthropod-borne viral pathogens. Over the past 20 years, the global dengue incidence has dramatically increased with epidemics of severe dengue where the case fatality rate can reach up to 20% in untreated patients. The association between Zika virus infection and severe congenital anomalies was first reported in 2015. Today no specific antiviral therapies are available for dengue and Zika virus infections, accentuating the need of adapted antiviral strategies based on medicinal plant drug discovery. Plants are a potential source of antiviral phytocompounds which act primarily by blocking virus entry in the host-cell. In the present study, we evaluated whether crude extracts from Stenocline ericoides DC. and Stenocline inuloides DC., two endemic plants from Madagascar, may have antiviral effects against dengue and Zika viruses. We showed that S. ericoides has virucidal action whereas S. inuloides inhibits the early steps of virus infection with a non-cytotoxic effect in human cells. The administration of S. ericoides and S. inuloides extracts in zebrafish had no effect on the behavior of animals at the active doses against dengue and Zika viruses, suggesting the absence of adverse effects at these doses. LC-HRMS2 and molecular networking analyses revealed the richness of these two plants in polyphenols and flavonoid with the presence of clusters of phytocompounds specific to each Stenocline species. Consequently, S. ericoides and S. inuloides represent potential sources for natural and safe antiviral phytocompounds against flaviviruses of medical concern.

Novel Antiviral Efficacy of Hedyotis diffusa and Artemisia capillaris Extracts against Dengue Virus, Japanese Encephalitis Virus, and Zika Virus Infection and Immunoregulatory Cytokine Signatures.

Currently, there are no specific therapeutics for flavivirus infections, including dengue virus (DENV) and Zika virus (ZIKV). In this study, we evaluated extracts from the plants Hedyotis diffusa (HD) and Artemisia capillaris (AC) to determine the antiviral activity against DENV, ZIKV, and Japanese encephalitis virus (JEV). HD and AC demonstrated inhibitory activity against JEV, ZIKV, and DENV replication and reduced viral RNA levels in a dose-responsive manner, with non-cytotoxic concentration ranging from 0.1 to 10 mg/mL. HD and AC had low cytotoxicity to Vero cells, with CC50 values of 33.7 ± 1.6 and 30.3 ± 1.7 mg/mL (mean ± SD), respectively. The anti-flavivirus activity of HD and AC was also consistent in human cell lines, including human glioblastoma (T98G), human chronic myeloid leukemia (K562), and human embryonic kidney (HEK-293T) cells. Viral-infected, HD-treated cells demonstrated downregulation of cytokines including CCR1, CCL26, CCL15, CCL5, IL21, and IL17C. In contrast, CCR1, CCL26, and AIMP1 were elevated following AC treatment in viral-infected cells. Overall, HD and AC plant extracts demonstrated flavivirus replication inhibitory activity, and together with immunoregulatory cytokine signatures, these results suggest that HD and AC possess bioactive compounds that may further be refined as promising candidates for clinical applications.

Mismatch Negativity is associated with affective social behavior in microcephaly.

Some children with severe microcephaly related to Zika virus infection show affective social-like behavior, such as smiling and rejection to a stranger's lap. Our objective was to check the association between this behavior and the occurrence of Mismatch Response (MMR) in event-related potentials. Twenty eight microcephalic children, aged 1-3 years, were divided in Affect(+) and Affect(-) groups, according to either the presence or absence of affective social-like behavior, respectively, and underwent the OddBall paradigm with vowels as auditory stimuli. MMR was statistically estimated comparing MMR sample means between both groups. The Affect(+) group significantly differed from the Affect(-) group and, as opposed to the latter, showed MMR as Mismatch Negativity (MMN) in the left occipital, left and right posterior temporal, and (especially) the right and median parietal leads. The relationship observed between MMN and affective social-like behavior suggests that these children may have cognitive mechanisms capable of providing some social interaction, despite their profound neurological dysfunction. MMN diagnostic techniques seem to be promising for the triage of microcephalic subjects regarding cognitive functions and for choosing a strategy for some social adaptation.

Cranberry Pomace Extract Exerts Antiviral Activity against Zika and Dengue Virus at Safe Doses for Adult Zebrafish.

Mosquito-borne dengue virus (DENV) and zika virus (ZIKV) infections constitute a global health emergency. Antivirals directly targeting the virus infectious cycle are still needed to prevent dengue hemorrhagic fever and congenital zika syndrome. In the present study, we demonstrated that Cranberry Pomace (CP) extract, a polyphenol-rich agrifood byproduct recovered following cranberry juice extraction, blocks DENV and ZIKV infection in human Huh7.5 and A549 cell lines, respectively, in non-cytotoxic concentrations. Our virological assays identified CP extract as a potential inhibitor of virus entry into the host-cell by acting directly on viral particles, thus preventing their attachment to the cell surface. At effective antiviral doses, CP extract proved safe and tolerable in a zebrafish model. In conclusion, polyphenol-rich agrifood byproducts such as berry extracts are a promising source of safe and naturally derived nutraceutical antivirals that target medically important pathogens.

Anti-Zika Virus Activity of Plant Extracts Containing Polyphenols and Triterpenes on Vero CCL-81 and Human Neuroblastoma SH-SY5Y Cells.

Zika virus (ZIKV) infection is a global threat associated to neurological disorders in adults and microcephaly in children born to infected mothers. No vaccine or drug is available against ZIKV. We herein report the anti-ZIKV activity of 36 plant extracts containing polyphenols and/or triterpenes. ZIKV-infected Vero CCL-81 cells were treated with samples at non-cytotoxic concentrations, determined by MTT and LDH assays. One third of the extracts elicited concentration-dependent anti-ZIKV effect, with viral loads reduction from 0.4 to 3.8 log units. The 12 active extracts were tested on ZIKV-infected SH-SY5Y cells and significant reductions of viral loads (in log units) were induced by Maytenus ilicifolia (4.5 log), Terminalia phaeocarpa (3.7 log), Maytenus rigida (1.7 log) and Echinodorus grandiflorus (1.7 log) extracts. Median cytotoxic concentration (CC50 ) of these extracts in Vero cells were higher than in SH-SY5Y lineage. M. ilicifolia (IC50 =16.8±10.3 µg/mL, SI=3.4) and T. phaeocarpa (IC50 =22.0±6.8 µg/mL, SI=4.8) were the most active extracts. UPLC-ESI-MS/MS analysis of M. ilicifolia extract led to the identification of 7 triterpenes, of which lupeol and a mixture of friedelin/friedelinol showed no activity against ZIKV. The composition of T. phaeocarpa extract comprises phenolic acids, ellagitannins and flavonoids, as recently reported by us. In conclusion, the anti-ZIKV activity of 12 plant extracts is here described for the first time and polyphenols and triterpenes were identified as the probable bioactive constituents of T. phaeocarpa and M. ilicifolia, respectively.

Itinerários Terapêuticos de familiares de crianças com Síndrome Congênita pelo Zika Vírus de uma cidade da região metropolitana de Salvador/Bahia / Therapeutic Journeys of family members of children with Congenital Zika Syndrome in the metropolitan region of Salvador/Bahia / Rutas terapéuticas de familiares de niños con síndrome congénito por el virus Zika en una ciudad de la zona metropolitana de Salvador/Bahia

Introdução: As condições de vida e saúde de crianças com Síndrome Congênita pelo Zika vírus (SCZV) constituem importante questão de Saúde Pública. As alterações no neurodesenvolvimento impactam na vida familiar e implicam cuidados multi e interdisciplinares. São necessários estudos de itinerários terapêuticos dos familiares em busca de assistência à saúde e educação. Objetivo: Conhecer os itinerários terapêuticos de familiares de crianças com SCZV de uma cidade da região metropolitana de Salvador/Bahia. Método: Estudo descritivo e transversal de abordagem qualitativa. Foram gravados, transcritos e analisados vídeos de entrevistas com oito familiares. Estabeleceram-se eixos temáticos: conhecimento e impacto do diagnóstico, busca e suporte no cuidado em saúde e inclusão educacional. Resultados: O conhecimento do diagnóstico da SCZV ocorreu depois do parto, para maioria dos familiares. Todos receberam orientação e encaminhamentos, principalmente, de profissionais da rede pública de saúde. As crianças foram encaminhadas para diferentes especialidades. Receberam prioridade em atendimento emergencial. Algumas participantes referiram angústia ao receber o diagnóstico, mudanças na dinâmica e vida familiar, longa espera para cadeira de rodas, dificuldades de acesso às instituições especializadas pela distância e falta de transporte e problemas na inclusão educacional por falta de auxiliares de sala. A maioria apontou o apoio de parentes e amigos. Conclusão: Os achados evidenciam os impactos dos itinerários terapêuticos na vida dessas famílias e as dificuldades enfrentadas pelas repercussões no neurodesenvolvimento das crianças na busca pela assistência. Os resultados contribuem para formulações de políticas públicas consonantes às necessidades dessas crianças.

Introduction: The living and health conditions of children with Congenital Zika Syndrome (CZS) are an important public health issue. Neurodevelopment changes impact family life and imply multi and interdisciplinary care.  Therefore, studies on the therapeutic journeys of family members in search for health care and education are needed. Objective: To investigate the therapeutic journeys of family members of children with SCZV in the metropolitan region of Salvador/Bahia. Methods: Descriptive and cross-sectional study with a qualitative approach, including recording, transcribing and analyzing videos of interviews with eight family members. The following thematic axes were defined: knowledge and impact of diagnosis, search and support in healthcare and educational inclusion. Results: Most family members became aware of the diagnosis of CZS only after the birth. All received guidance and referrals, mainly from public health professionals. The children were referred to different specializations and received priority assistance. Some participants reported anguish receiving the diagnosis, changes in dynamics and family life, long waiting for a wheelchair, difficulties to access specialized institutions due to distance and lack of transportation, and problems in educational inclusion due to the lack of classroom assistants. Most family members reported having support from relatives and friends. Conclusion: The findings show the impacts of therapeutic journeys on the lives of these families and the difficulties faced due to the effects on the neurodevelopment of children in search for assistance. The results suggest the need to formulate public policies in line with the needs of these children.

Introducción: Las condiciones de vida y de salud de los niños con síndrome congénito por el virus Zika congénito (SCZV) son un importante problema de salud pública. Los cambios del neurodesarrollo impactan la vida familiar y implican cuidados multidisciplinarios y interdisciplinarios. Son necesarios estudios sobre rutas terapéuticas de los familiares en busca de atención sanitaria y educación. Objetivo: Conocer las rutas terapéuticas de familiares de niños con SCZV en una ciudad de la zona metropolitana de Salvador/Bahia. Métodos: Estudio descriptivo y transversal con abordaje cualitativo. Las entrevistas de ocho familiares fueron videograbadas, transcritas y analizadas. Se establecieron ejes temáticos: conocimiento y impacto del diagnóstico, búsqueda y apoyo en salud y educación inclusiva. Resultados: El conocimiento del diagnóstico de SCZV ocurrió después del parto para la mayoría de los familiares. Todos recibieron orientación y derivaciones, principalmente de profesionales de salud pública. Los niños referidos a diferentes especialidades. Recibieron prioridad en la atención. Algunos participantes refirieron angustia al recibir el diagnóstico, cambios en la dinámica y la vida familiar, larga espera por silla de ruedas, dificultades para acceder a instituciones especializadas por la distancia y falta de transporte y educación inclusiva por falta del maestro asistente. La mayoría señaló el apoyo de familiares y amigos. Conclusión: Hallazgos muestran lo impacto en las rutas terapéuticas en la vida de estas familias y las dificultades frente las repercusiones del neurodesarrollo infantil en la búsqueda de cuidados. Los resultados contribuyen a la formulación de políticas públicas para atender las necesidades de estos niños.

Searching for plant-derived antivirals against dengue virus and Zika virus.

BACKGROUND: The worldwide epidemics of diseases as dengue and Zika have triggered an intense effort to repurpose drugs and search for novel antivirals to treat patients as no approved drugs for these diseases are currently available. Our aim was to screen plant-derived extracts to identify and isolate compounds with antiviral properties against dengue virus (DENV) and Zika virus (ZIKV). METHODS: Seven thousand plant extracts were screened in vitro for their antiviral properties against DENV-2 and ZIKV by their viral cytopathic effect reduction followed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method, previously validated for this purpose. Selected extracts were submitted to bioactivity-guided fractionation using high- and ultrahigh-pressure liquid chromatography. In parallel, high-resolution mass spectrometric data (MSn) were collected from each fraction, allowing compounds into the active fractions to be tracked in subsequent fractionation procedures. The virucidal activity of extracts and compounds was assessed by using the plaque reduction assay. EC50 and CC50 were determined by dose response experiments, and the ratio (EC50/CC50) was used as a selectivity index (SI) to measure the antiviral vs. cytotoxic activity. Purified compounds were used in nuclear magnetic resonance spectroscopy to identify their chemical structures. Two compounds were associated in different proportions and submitted to bioassays against both viruses to investigate possible synergy. In silico prediction of the pharmacokinetic and toxicity (ADMET) properties of the antiviral compounds were calculated using the pkCSM platform. RESULTS: We detected antiviral activity against DENV-2 and ZIKV in 21 extracts obtained from 15 plant species. Hippeastrum (Amaryllidaceae) was the most represented genus, affording seven active extracts. Bioactivity-guided fractionation of several extracts led to the purification of lycorine, pretazettine, narciclasine, and narciclasine-4-O-ß-D-xylopyranoside (NXP). Another 16 compounds were identified in active fractions. Association of lycorine and pretazettine did not improve their antiviral activity against DENV-2 and neither to ZIKV. ADMET prediction suggested that these four compounds may have a good metabolism and no mutagenic toxicity. Predicted oral absorption, distribution, and excretion parameters of lycorine and pretazettine indicate them as candidates to be tested in animal models. CONCLUSIONS: Our results showed that plant extracts, especially those from the Hippeastrum genus, can be a valuable source of antiviral compounds against ZIKV and DENV-2. The majority of compounds identified have never been previously described for their activity against ZIKV and other viruses.

Identification of potential ZIKV NS2B-NS3 protease inhibitors from Andrographis paniculata: An insilico approach.

Andrographis paniculata is a widely used medicinal plant for treating a variety of human infections. The plant's bioactives have been shown to have a variety of biological activities in various studies, including potential antiviral, anticancer, and anti-inflammatory effects in a variety of experimental models. The present investigation identifies a potent antiviral compound from the phytochemicals of Andrographis paniculata against Zika virus using computational docking simulation. The ZIKV NS2B-NS3 protease, which is involved in viral replication, has been considered as a promising target for Zika virus drug development. The bioactives from Andrographis paniculata, along with standard drugs as control were screened for their binding energy using AutoDock 4.2 against the viral protein. Based on the higher binding affinity the phytocompounds Bisandrographolide A (-11.7), Andrographolide (-10.2) and Andrographiside (-9.7) have convenient interactions at the binding site of target protein (ZIKV NS2B-NS3 protease) in comparison with the control drug. In addition, using insilico tools, the selected high-scoring molecules were analysed for pharmacological properties such as ADME (Absorption, Distribution, Metabolism, and Excretion profile) and toxicity. Andrographolide was reported to have strong pharmacodynamics properties and target accuracy based on the Lipinski rule and lower binding energy. The selected bioactives showed lower AMES toxicity and has potent antiviral activity against zika virus targets. Further, MD simulation studies validated Bisandrographolide A & Andrographolide as a potential hit compound by exhibiting good binding with the target protein. The compounds exhibited good hydrogen bonds with ZIKV NS2B-NS3 protease. As a result, bioactives from the medicinal plant Andrographis paniculata can be studied in vitro and in vivo to develop an antiviral phytopharmaceutical for the successful treatment of zika virus.Communicated by Ramaswamy H. Sarma.

Dysregulated metabolism underpins Zika-virus-infection-associated impairment in fetal development.

Zika virus (ZIKV) is an Aedes-mosquito-borne flavivirus that causes debilitating congenital and developmental disorders. Improved understanding of ZIKV pathogenesis could assist efforts to fill the therapeutic and vaccine gap. We use several ZIKV strains, including a pair differing by a single phenylalanine-to-leucine substitution (M-F37L) in the membrane (M) protein, coupled with unbiased genomics to demarcate the border between attenuated and pathogenic infection. We identify infection-induced metabolic dysregulation as a minimal set of host alterations that differentiates attenuated from pathogenic ZIKV strains. Glycolytic rewiring results in impaired oxidative phosphorylation and mitochondrial dysfunction that trigger inflammation and apoptosis in pathogenic but not attenuated ZIKV strains. Critically, pyruvate supplementation prevents cell death, in vitro, and rescues fetal development in ZIKV-infected dams. Our findings thus demonstrate dysregulated metabolism as an underpinning of ZIKV pathogenicity and raise the potential of pyruvate supplementation in expectant women as a prophylaxis against congenital Zika syndrome.

Bisbenzylisoquinoline Alkaloids of Cissampelos Sympodialis With in Vitro Antiviral Activity Against Zika Virus.

In search of new antiviral compounds against Zika virus we conducted a bioassay-guided fractionation of bisbenzyilisoquinoline alkaloids isolated from Cissampelos sympodialis (Menispermaceae), a medicinal plant species endemic to Brazil. Six subfractions were obtained from a tertiary alkaloidal fraction of the rhizomes (TAFrz) using preparative high-performance liquid chromatography. All the subfractions were tested against Zika virus-infected Vero cells as the cellular model to evaluate cytotoxicity and antiviral effective concentrations. The results showed that three of the six TAFrz subfractions tested were active. The most active ones were the subfraction 6 (that consisted of the alkaloids methylwarifteine and warifteine present as a mixture at a ratio of 8.8:1.2 respectively) and the subfraction 5, that was later identified as warifteine, the major tertiary alkaloid of this species. Warifteine was able to significantly reduce virus titer in Zika virus-infected Vero cells with an IC50 of 2.2 µg/ml and this effect was selective (selectivity index, SI = 68.3). Subfraction 6 had an IC50 = 3.5 µg/ml and was more cytotoxic than pure warifteine, with SI = 6.14. Fraction 5 and fraction 6 were more potent in decreasing the viral titer of Zika virus-infected Vero cells than 6-methylmercaptopurine riboside (IC50 = 24.5 µg/ml and SI = 11.9), a mercaptopurine riboside with ZIKV antiviral activity used as a positive control. Our data demonstrate that alkaloids of the bisbenzylisoquinoline type may be explored as new antiviral agents or as an useful pharmacophore for investigating ZIKV antiviral activity.

The Compound SBI-0090799 Inhibits Zika Virus Infection by Blocking De Novo Formation of the Membranous Replication Compartment.

Zika virus (ZIKV) is a mosquito-borne pathogen classified by the World Health Organization (WHO) as a public health emergency of international concern in 2016, and it is still identified as a priority disease. Although most infected individuals are asymptomatic or show mild symptoms, a risk of neurologic complications is associated with infection in adults. Additionally, infection during pregnancy is directly linked to microcephaly and other congenital malformations. Since there are no currently available vaccines or approved therapeutics for this virus, there is a critical unmet need in developing treatments to prevent future ZIKV outbreaks. Toward this end, we performed a large-scale cell-based high-content screen of 51,520 chemical compounds to identify potential antiviral drug candidates. The compound (2E)-N-benzyl-3-(4-butoxyphenyl)prop-2-enamide (SBI-0090799) was found to inhibit replication of multiple ZIKV strains and in different cell systems. SBI-0090799 did not affect viral entry or RNA translation but suppressed RNA replication by preventing the formation of the membranous replication compartment. Selection of drug-resistant viruses identified single-amino-acid substitutions in the N-terminal region of nonstructural protein NS4A, arguing this is the likely drug target. These resistance mutations rescued viral RNA replication and restored the formation of the membranous replication compartment. This mechanism of action is similar to clinically approved NS5A inhibitors for hepatitis C virus (HCV). Taken together, SBI-0090799 represents a promising lead candidate for the development of an antiviral treatment against ZIKV infection for the mitigation of severe complications and potential resurgent outbreaks of the virus. IMPORTANCE This study describes the elucidation of (2E)-N-benzyl-3-(4-butoxyphenyl)prop-2-enamide (SBI-0090799) as a selective and potent inhibitor of Zika virus (ZIKV) replication using a high-throughput screening approach. Mapping and resistance studies, supported by electron microscopy observations, indicate that the small molecule is functioning through inhibition of NS4A-mediated formation of ZIKV replication compartments in the endoplasmic reticulum (ER). Intriguingly, this defines a novel nonenzymatic target and chemical matter for the development of a new class of ZIKV antivirals. Moreover, chemical modulation affecting this nonstructural protein mirrors the identification and development of hepatitis C virus (HCV) NS5A inhibitor daclatasvir and its derivatives, similarly interfering with the formation of the viral replication compartment and also targeting a protein with no enzymatic activity, which have been part of a curative strategy for HCV.

Transient Receptor Potential Vanilloid 1 (TRPV1) as a plausible novel therapeutic target for treating neurological complications in ZikaVirus.

Zika virus was declared a national emergency by WHO (World Health Organization) in 2016 when its widespread outbreaks and life-threatening complications were reported, especially in newborns and adults. Numerous studies reported that neuroinflammation is one of the significant root-causes behind its major neurological complications like microcephaly and Guillain-Barré syndrome (GBS). In this hypothesis, we propose Transient Receptor Potential Vanilloid 1 channel (TRPV1) as a major culprit in triggering positive inflammatory loop, ultimately leading to sustained neuroinflammation, one of the key clinical findings in Zika induced microcephalic and GBS patients. Opening of TRPV1 channel also leads to calcium influx and oxidative stress that ultimately results in cellular apoptosis (like Schwann cell in GBS and developing fetal nerve cells in microcephaly), ultimately leading to these complications. Currently, no specific cure exists for these complications. Most of the antiviral candidates are under clinical trials. Though there is no direct research on TRPV1 as a cause of Zika virus's neurological complications, but similarity in mechanisms is undeniable. Thus, exploring pathobiological involvement of TRPV1 channels and various TRPV1 modulators in these complications can possibly prove to be an effective futuristic therapeutic strategy for treatment and management of these life-threatening complications.

Mother-to-Child Transmission of Arboviruses during Breastfeeding: From Epidemiology to Cellular Mechanisms.

Most viruses use several entry sites and modes of transmission to infect their host (parenteral, sexual, respiratory, oro-fecal, transplacental, transcutaneous, etc.). Some of them are known to be essentially transmitted via arthropod bites (mosquitoes, ticks, phlebotomes, sandflies, etc.), and are thus named arthropod-borne viruses, or arboviruses. During the last decades, several arboviruses have emerged or re-emerged in different countries in the form of notable outbreaks, resulting in a growing interest from scientific and medical communities as well as an increase in epidemiological studies. These studies have highlighted the existence of other modes of transmission. Among them, mother-to-child transmission (MTCT) during breastfeeding was highlighted for the vaccine strain of yellow fever virus (YFV) and Zika virus (ZIKV), and suggested for other arboviruses such as Chikungunya virus (CHIKV), dengue virus (DENV), and West Nile virus (WNV). In this review, we summarize all epidemiological and clinical clues that suggest the existence of breastfeeding as a neglected route for MTCT of arboviruses and we decipher some of the mechanisms that chronologically occur during MTCT via breastfeeding by focusing on ZIKV transmission process.

Therapeutic targets and biological mechanisms of action of curcumin against Zika virus: In silico and in vitro analyses.

Zika virus (ZIKV) is a mosquito-borne flavivirus, that could cause congenital Zika syndrome (CZS), characterized by microcephaly, neurological complications and fetal deaths. No specific treatments for ZIKV are currently available, highlighting the urgent global need to identify and develop therapeutic agents. Drug repositioning of approved natural compounds can provide effective alternative solutions for novel antiviral development. The current study focused on curcumin, a component of turmeric known to exert diverse antiviral effects. We integrated in silico information from publicly available databases to predict interactions between curcumin and potential targets of ZIKV. In our network analysis, we identified four targets, TP53, AKT1, PTEN, and TNF, which were identified as potential targets associated with ZIKV. Based on retrieved targets, we performed molecular docking study and identified curcumin-TNF showed the strongest binding among four targets. The anti-Zika effects of curcumin were validated in vitro with the aid of antiviral and plaque reduction assay. Curcumin at concentrations ranging from 12.5 to 50 µM displayed significant antiviral activity in a dose-dependent manner (p < 0.05). In view of its natural abundance and prevalence in the human diet, curcumin holds significant promise for treatment of ZIKV infections.

Antiviral Compounds for Blocking Arboviral Transmission in Mosquitoes.

Mosquito-borne arthropod-borne viruses (arboviruses) such as the dengue virus (DENV), Zika virus (ZIKV), and chikungunya virus (CHIKV) are important human pathogens that are responsible for significant global morbidity and mortality. The recent emergence and re-emergence of mosquito-borne viral diseases (MBVDs) highlight the urgent need for safe and effective vaccines, therapeutics, and vector-control approaches to prevent MBVD outbreaks. In nature, arboviruses circulate between vertebrate hosts and arthropod vectors; therefore, disrupting the virus lifecycle in mosquitoes is a major approach for combating MBVDs. Several strategies were proposed to render mosquitoes that are refractory to arboviral infection, for example, those involving the generation of genetically modified mosquitoes or infection with the symbiotic bacterium Wolbachia. Due to the recent development of high-throughput screening methods, an increasing number of drugs with inhibitory effects on mosquito-borne arboviruses in mammalian cells were identified. These antivirals are useful resources that can impede the circulation of arboviruses between arthropods and humans by either rendering viruses more vulnerable in humans or suppressing viral infection by reducing the expression of host factors in mosquitoes. In this review, we summarize recent advances in small-molecule antiarboviral drugs in mammalian and mosquito cells, and discuss how to use these antivirals to block the transmission of MBVDs.

Himatanthus bracteatus stem extracts present anti-flavivirus activity while an isolated sesquiterpene glucoside present only anti-Zika virus activity in vitro.

The hexane and ethanol extracts from Himatanthus bracteatus (Apocynaceae) stems were evaluated for antiviral activity against Zika virus, yellow fever virus and dengue virus 2 and for cytotoxicity in Vero cells by MTT assay. The ethanol extract showed good antiviral activity against the three viruses with selective indexes (SI) > 10 and its fractionation led to the isolation of the known plumieride that was active only against Zika virus (SI of 15.97).