Mathematical models of in vitro viral kinetics help us understand and quantify the main determinants underlying the virus-host cell interactions. We aimed to provide a numerical characterization of the Zika virus (ZIKV) in vitro infection kinetics, an arthropod-borne emerging virus that has gained public recognition due to its association with microcephaly in newborns. The mathematical model of in vitro viral infection typically assumes that degradation of extracellular infectious virus proceeds in an exponential manner, that is, each viral particle has the same probability of losing infectivity at any given time. We incubated ZIKV stock in the cell culture media and sampled with high frequency for quantification over the course of 96 h. The data showed a delay in the virus degradation in the first 24 h followed by a decline, which could not be captured by the model with exponentially distributed decay time of infectious virus. Thus, we proposed a model, in which inactivation of infectious ZIKV is gamma distributed and fit the model to the temporal measurements of infectious virus remaining in the media. The model was able to reproduce the data well and yielded the decay time of infectious ZIKV to be 40 h. We studied the in vitro ZIKV infection kinetics by conducting cell infection at two distinct multiplicity of infection and measuring viral loads over time. We fit the mathematical model of in vitro viral infection with gamma distributed degradation time of infectious virus to the viral growth data and identified the timespans and rates involved within the ZIKV-host cell interplay. Our mathematical analysis combined with the data provides a well-described example of non-exponential viral decay dynamics and presents numerical characterization of in vitro infection with ZIKV.
- Klíčová slova
- Zika virus, in vitro viral kinetics, mathematical model, viral decay,
- MeSH
- Cercopithecus aethiops MeSH
- infekce virem zika virologie MeSH
- kinetika MeSH
- replikace viru * MeSH
- reprodukovatelnost výsledků MeSH
- teoretické modely * MeSH
- Vero buňky MeSH
- virová nálož MeSH
- virus zika růst a vývoj fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
Zika virus (ZIKV) has spread in the Americas since 2015 and the potential establishment of a sylvatic transmission cycle in the continent has been hypothesized. We evaluated vector competence of five sylvatic Neotropical mosquito species to two ZIKV isolates. Distinct batches of Haemagogus leucoceleanus, Sabethes albiprivus, Sabethes identicus, Aedes terrens and Aedes scapularis females were respectively orally challenged and inoculated intrathoracically with ZIKV. Orally challenged mosquitoes were refractory or exhibited low infection rates. Viral dissemination was detected only in Hg. leucocelaenus, but with very low rates. Virus was not detected in saliva of any mosquito orally challenged with ZIKV, regardless of viral isolate and incubation time. When intrathoracically injected, ZIKV disseminated in high rates in Hg. leucocelaenus, Sa. identicus and Sa. albpiprivus, but low transmission was detected in these species; very low dissemination and no transmission was detected in Ae. terrens and Ae. scapularis. Together these results suggest that genetically determined tissue barriers, especially in the midgut, play a vital role in inhibiting ZIKV for transmission in the tested sylvatic mosquito species. Thus, an independent enzootic transmission cycle for ZIKV in South America is very unlikely.
- MeSH
- infekce přenášené vektorem MeSH
- infekce virem zika diagnóza epidemiologie přenos virologie MeSH
- komáří přenašeči virologie MeSH
- lidé MeSH
- ochrana veřejného zdraví MeSH
- virová nálož MeSH
- virus zika * klasifikace genetika MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Jižní Amerika epidemiologie MeSH
Zika and Dengue viruses have attracted substantial attention from researchers in light of recent outbreaks of Dengue fever and increases in cases of congenital microcephaly in areas with Zika incidence. This review summarizes the current state of knowledge about Zika and Dengue proteases. These enzymes have several interesting features: 1) NS3 serine protease requires the activating co-factor NS2B, which is anchored in the membrane of the endoplasmic reticulum; 2) NS2B displays extensive conformational dynamics; 3) NS3 is a multidomain protein with proteolytic, NTPase, RNA 5' triphosphatase and helicase activity and has many protein-protein interaction partners; 4) NS3 is autoproteolytically released from its precursor. Attempts to design tight-binding and specific active-site inhibitors are complicated by the facts that the substrate pocket of the NS2B-NS3 protease is flat and the active-site ligands are charged. The ionic character of potential active-site inhibitors negatively influences their cell permeability. Possibilities to block cis-autoprocessing of the protease precursor have recently been considered. Additionally, potential allosteric sites on NS2B-NS3 proteases have been identified and allosteric compounds have been designed to impair substrate binding and/or block the NS2B-NS3 interaction. Such compounds could be specific to viral proteases, without off-target effects on host serine proteases, and could have favorable pharmacokinetic profiles. This review discusses various groups of inhibitors of these proteases according to their mechanisms of action and chemical structures.
- Klíčová slova
- Active-site inhibitors, Allosteric inhibitors, Aptamers, Dengue protease, Precursor, Zika protease,
- MeSH
- alosterické místo MeSH
- antivirové látky chemie farmakologie MeSH
- dengue farmakoterapie virologie MeSH
- infekce virem zika farmakoterapie virologie MeSH
- inhibitory proteas chemie farmakologie MeSH
- katalytická doména MeSH
- kinetika MeSH
- konformace proteinů MeSH
- lidé MeSH
- proteasy chemie metabolismus MeSH
- racionální návrh léčiv * MeSH
- serinové endopeptidasy chemie metabolismus MeSH
- virové proteiny antagonisté a inhibitory chemie metabolismus MeSH
- virus dengue účinky léků enzymologie MeSH
- virus zika účinky léků enzymologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Názvy látek
- antivirové látky MeSH
- inhibitory proteas MeSH
- NS3 protease, dengue virus MeSH Prohlížeč
- NS3 protein, zika virus MeSH Prohlížeč
- proteasy MeSH
- serinové endopeptidasy MeSH
- virové proteiny MeSH
Zika virus is a global health threat due to significantly elevated risk of fetus malformations in infected pregnant women. Currently, neither an effective therapy nor a prophylactic vaccination is available for clinical use, desperately necessitating novel therapeutics and approaches to obtain them. Here, we present a structural model of the Zika virus RNA-dependent RNA polymerase (ZIKV RdRp) in complex with template and nascent RNAs, Mg2+ ions and accessing nucleoside triphosphate. The model allowed for docking studies aimed at effective pre-screening of potential inhibitors of ZIKV RdRp. Applicability of the structural model for docking studies was illustrated with the NITD008 artificial nucleotide that is known to effectively inhibit the function of the ZIKV RdRp. The ZIKV RdRp - RNA structural model is provided for all possible variations of the nascent RNA bases pairs to enhance its general utility in docking and modelling experiments. The developed model makes the rational design of novel nucleosides and nucleotide analogues feasible and thus provides a solid platform for the development of advanced antiviral therapy.
- MeSH
- adenosin analogy a deriváty chemie farmakologie MeSH
- hořčík chemie MeSH
- infekce virem zika genetika virologie MeSH
- konformace proteinů účinky léků MeSH
- lidé MeSH
- molekulární modely MeSH
- nukleosidy chemie MeSH
- nukleotidy chemie MeSH
- polyfosfáty chemie MeSH
- replikace viru genetika MeSH
- RNA-dependentní RNA-polymerasa chemie genetika MeSH
- RNA chemie genetika MeSH
- simulace molekulového dockingu MeSH
- virové nestrukturální proteiny chemie genetika MeSH
- virus zika chemie genetika patogenita MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- adenosin MeSH
- hořčík MeSH
- NITD008 MeSH Prohlížeč
- nukleosidy MeSH
- nukleotidy MeSH
- polyfosfáty MeSH
- RNA-dependentní RNA-polymerasa MeSH
- RNA MeSH
- triphosphoric acid MeSH Prohlížeč
- virové nestrukturální proteiny MeSH
BACKGROUND: The recent Zika virus (ZIKV) outbreak has linked ZIKV with microcephaly and other central nervous system pathologies in humans. Astrocytes are among the first cells to respond to ZIKV infection in the brain and are also targets for virus infection. In this study, we investigated the interaction between ZIKV and primary human brain cortical astrocytes (HBCA). RESULTS: HBCAs were highly sensitive to representatives of both Asian and African ZIKV lineages and produced high viral yields. The infection was associated with limited immune cytokine/chemokine response activation; the highest increase of expression, following infection, was seen in CXCL-10 (IP-10), interleukin-6, 8, 12, and CCL5 (RANTES). Ultrastructural changes in the ZIKV-infected HBCA were characterized by electron tomography (ET). ET reconstructions elucidated high-resolution 3D images of the proliferating and extensively rearranged endoplasmic reticulum (ER) containing viral particles and virus-induced vesicles, tightly juxtaposed to collapsed ER cisternae. CONCLUSIONS: The results confirm that human astrocytes are sensitive to ZIKV infection and could be a source of proinflammatory cytokines in the ZIKV-infected brain tissue.
- Klíčová slova
- Astrocyte, Electron tomography, Flavivirus, Immune response, Luminex, Zika virus,
- MeSH
- astrocyty virologie MeSH
- cytokiny metabolismus MeSH
- endoplazmatické retikulum virologie MeSH
- infekce virem zika virologie MeSH
- kultivované buňky MeSH
- lidé MeSH
- mozek virologie MeSH
- virus zika patogenita MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- cytokiny MeSH
The rapid succession of the pandemic of arbovirus diseases, such as dengue, West Nile fever, chikungunya, and Zika fever, has intensified research on these and other arbovirus diseases worldwide. Investigating the unique mode of vector-borne transmission requires a clear understanding of the roles of vertebrates. One major obstacle to this understanding is the ambiguity of the arbovirus definition originally established by the World Health Organization. The paucity of pertinent information on arbovirus transmission at the time contributed to the notion that vertebrates played the role of reservoir in the arbovirus transmission cycle. Because this notion is a salient feature of the arbovirus definition, it is important to reexamine its validity. This review addresses controversial issues concerning vertebrate reservoirs and their role in arbovirus persistence in nature, examines the genesis of the problem from a historical perspective, discusses various unresolved issues from multiple points of view, assesses the present status of the notion in light of current knowledge, and provides options for a solution to resolve the issue.
- Klíčová slova
- arbovirus, host range, insect-specific virus, origin of arbovirus, transmission mechanism, vertebrate reservoir, virus maintenance, zoonosis,
- MeSH
- arbovirové infekce přenos virologie MeSH
- arboviry izolace a purifikace MeSH
- Culicidae virologie MeSH
- dengue přenos virologie MeSH
- hostitelská specificita MeSH
- infekce virem zika přenos virologie MeSH
- lidé MeSH
- myši MeSH
- obratlovci virologie MeSH
- západonilská horečka přenos MeSH
- zdroje nemoci virologie MeSH
- zoonózy MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
BACKGROUND: The outbreak of Zika virus (ZIKV) in the Americas has transformed a previously obscure mosquito-transmitted arbovirus of the Flaviviridae family into a major public health concern. Little is currently known about the evolution and biology of ZIKV and the factors that contribute to the associated pathogenesis. Determining genomic sequences of clinical viral isolates and characterization of elements within these are an important prerequisite to advance our understanding of viral replicative processes and virus-host interactions. METHODOLOGY/PRINCIPAL FINDINGS: We obtained a ZIKV isolate from a patient who presented with classical ZIKV-associated symptoms, and used high throughput sequencing and other molecular biology approaches to determine its full genome sequence, including non-coding regions. Genome regions were characterized and compared to the sequences of other isolates where available. Furthermore, we identified a subgenomic flavivirus RNA (sfRNA) in ZIKV-infected cells that has antagonist activity against RIG-I induced type I interferon induction, with a lesser effect on MDA-5 mediated action. CONCLUSIONS/SIGNIFICANCE: The full-length genome sequence including non-coding regions of a South American ZIKV isolate from a patient with classical symptoms will support efforts to develop genetic tools for this virus. Detection of sfRNA that counteracts interferon responses is likely to be important for further understanding of pathogenesis and virus-host interactions.
- MeSH
- buňky A549 MeSH
- DEAD box protein 58 metabolismus MeSH
- epidemický výskyt choroby MeSH
- fylogeneze MeSH
- genom virový * MeSH
- infekce virem zika virologie MeSH
- interakce hostitele a patogenu MeSH
- interferon typ I antagonisté a inhibitory biosyntéza genetika MeSH
- lidé MeSH
- replikace viru MeSH
- RNA virová genetika izolace a purifikace MeSH
- Vero buňky MeSH
- virus zika genetika izolace a purifikace patogenita fyziologie MeSH
- vysoce účinné nukleotidové sekvenování MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Brazílie epidemiologie MeSH
- Názvy látek
- DEAD box protein 58 MeSH
- interferon typ I MeSH
- RNA virová MeSH
