Tick-borne encephalitis (TBE) represents one of the most important and serious viral neuroinfections in Europe and North-eastern Asia. Despite the medical importance of this disease, there is no specific treatment of TBE. In our laboratory, we identified nucleoside analogues with high antiviral effect against TBE virus (TBEV) observed in vitro as well as in TBEV-infected mice (reduction of viral titers in the brain, reduction of clinical signs of neuroinfection, prolonged mean survival time, lower mortality). The main goal of this project is to modify these effective molecules into prodrug forms with increased therapeutical potential based on efficient crossing the blood-brain barrier and targeted delivery to the central nervous system. We will experimentally combine these antiviral molecules with immunomodulatory therapies with the purpose to maximize viral clearance and minimize immunopathology after TBEV infection in the central nervous system. The results should provide new and important data about the possibilities and directions of antiviral and immunomodulatory therapy of T...

Klíšťová encefalitida (KE) je jednou z nejvýznamnějších a nejzávažnějších virových neuroinfekcí v Evropě a severovýchodní Asii. Navzdory značnému medicínskému významu stále neexistují specifické možnosti terapie tohoto onemocnění. V naší laboratoři jsme identifikovali nukleosidové analogy, které vykazují vysoký inhibiční efekt vůči viru KE v podmínkách in vitro a v případě experimentální terapie KE u laboratorních myší redukují titry viru v mozku, zmírňují klinické projevy neuroinfekce, zvyšují střední dobu přežití a redukují letalitu. Cílem projektu je navrhnout a provést syntézu proléčiv vycházejících z těchto nízkomolekulárních látek s cíleným terapeutickým účinkem daným vyšší prostupností hematoencefalickou bariérou a vyšší afinitou k CNS. Cílenou antivirovou léčbu budeme experimentálně kombinovat s imunomodulačními látkami za účelem maximální likvidace viru a současně minimální (neuro)imunopatologie v CNS. Výsledky projektu přinesou nové poznatky týkající se možností a směřování antivirové a imunomodulační terapie KE.

• MeSH
• antivirové látky MeSH
• imunomodulace MeSH
• imunomodulační látky MeSH
• klíšťová encefalitida prevence a kontrola   MeSH
• kombinovaná terapie MeSH
• lidé MeSH
• prekurzory léčiv MeSH
• viry klíšťové encefalitidy účinky léků   MeSH
• vyvíjení léků MeSH
• Check Tag
• lidé MeSH

• Konspekt
• Farmacie. Farmakologie
• NLK Obory
• farmacie a farmakologie
• preventivní medicína
• NLK Publikační typ
• závěrečné zprávy o řešení grantu AZV MZ ČR

The nucleoside/nucleotide derived antiviral agents have been the most important components of antiviral therapy used in clinics. Recently, the focus of the medicinal chemists within this exciting research field has been affected mainly by the lack of effective therapies for the Hepatitis C virus (HCV) infection and several other "neglected" diseases caused by viruses such as Zika or Dengue. 2'-Methyl modified nucleosides and their monophosphate prodrugs (ProTides) have revolutionized the therapies for HCV in the last few years and, according to the latest research efforts, have also brought a promise for treatment of diseases caused by other members of Flaviviridae family. Here, we report on the design and synthesis of 5'-N and S modified ProTides derived from 2'-methyladenosine. We studied potential applicability of these derivatives as prodrugs of this archetypal antiviral compound.

• MeSH
• adenosin analogy a deriváty   chemie   MeSH
• antivirové látky chemická syntéza   chemie   farmakologie   MeSH
• dusík chemie   MeSH
• Hepacivirus účinky léků   MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie MeSH
• nukleotidy chemie   metabolismus   farmakologie   MeSH
• prekurzory léčiv chemická syntéza   chemie   farmakologie   MeSH
• síra chemie   MeSH
• virus dengue účinky léků   MeSH
• virus zika účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Vector-borne flaviviruses (VBFs) affect human health worldwide, but no approved drugs are available specifically to treat VBF-associated infections. Here, we performed in silico screening of a library of U.S. Food and Drug Administration-approved antiviral drugs for their interaction with Zika virus proteins. Twelve hit drugs were identified by the docking experiments and tested in cell-based antiviral assay systems. Efavirenz, tipranavir, and dasabuvir at micromolar concentrations were identified to inhibit all VBFs tested; i.e., two representatives of mosquito-borne flaviviruses (Zika and West Nile viruses) and one representative of flaviviruses transmitted by ticks (tick-borne encephalitis virus). The results warrant further research into these drugs, either individually or in combination, as possible pan-flavivirus inhibitors.

• Publikační typ
• časopisecké články MeSH

Tick-borne encephalitis virus (TBEV) is a medically important representative of the Flaviviridae family. The TBEV genome encodes a single polyprotein, which is co/post-translationally cleaved into three structural and seven non-structural proteins. Of the non-structural proteins, NS5, contains an RNA-dependent RNA polymerase (RdRp) domain that is highly conserved and is responsible for the genome replication. Screening for potential antivirals was done using a hybrid receptor and ligand-based pharmacophore search likely targeting the RdRp domain. For the identification of pharmacophores, a mixture of small probe molecules and nucleotide triphosphates were used. The ligand/receptor interaction screenings of structures from the ZINC database resulted in five compounds. Zinc 3677 and 7151 exhibited lower cytotoxicity and were tested for their antiviral effect against TBEV in vitro. Zinc 3677 inhibited TBEV at micromolar concentrations. The results indicate that Zinc 3677 represents a good target for structure-activity optimizations leading potentially to a discovery of effective TBEV antivirals.

• MeSH
• antivirové látky farmakologie   MeSH
• inhibitory enzymů farmakologie   MeSH
• klíšťata virologie   MeSH
• klíšťová encefalitida virologie   MeSH
• lidé MeSH
• replikace viru účinky léků   MeSH
• RNA-dependentní RNA-polymerasa antagonisté a inhibitory   genetika   metabolismus   MeSH
• virové proteiny antagonisté a inhibitory   genetika   metabolismus   MeSH
• viry klíšťové encefalitidy účinky léků   enzymologie   genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Klíšťová encefalitida (KE) je jednou z nejvýznamnějších virových neuroinfekcí člověka. KE se vyskytuje napříč euroasijským kontinentem – od západní Evropy přes Rusko až po Japonsko. Účinnou prevencí před nákazou virem KE je očkování. Na území Ruské federace je dostupný preparát obsahující specifické lidské imunoglobuliny proti viru KE, který je aplikován jako postexpoziční profylaxe, jakmile se prokáže, že na člověku sálo infikované klíště. Včas podaný preparát poskytuje ochranu před rozvojem KE u téměř 80 % subjektů. V Evropě (mimo území Ruské federace) bylo používání postexpoziční profylaxe KE zastaveno kvůli obavám z protilátkami zesílené infektivity viru KE po podání imunoglobulinového preparátu. V současné době je věnována značná pozornost vývoji nové generace preparátů pro postexpoziční profylaxi KE. Tento přehledový článek se zabývá též otázkou možného opětovného zavedení postexpoziční imunoglobulinové profylaxe v zemích Evropské unie.

Tick-borne encephalitis (TBE) is one of the most important human viral neuroinfections. TBE is prevalent over large areas of the Eurasia – from Western Europe through Russia to Japan. TBE can be effectively prevented by vaccination. In Russia, specific immunoglobulins against TBE virus are used for postexposure prophylaxis. The immunoglobulins are applied in all cases of human infestation with an infected tick. Timely administered immunoglobulin provides protection against TBE in almost 80 % of cases. In Europe (outside Russia), the use of human specific immunoglobulin was discontinued due to concerns about antibody-dependent enhancement of TBE virus infectivity. At present, there are many efforts to develop a new generation of immunoglobulin preparations for postexposure prophylaxis of TBE. This review article debates possible re-introduction of specific anti-TBE virus immunoglobulins for postexposure prophylaxis in EU countries.

• MeSH
• Evropská unie MeSH
• imunoglobuliny farmakologie   škodlivé účinky   terapeutické užití   MeSH
• incidence MeSH
• klíšťová encefalitida * epidemiologie   přenos   prevence a kontrola   MeSH
• preexpoziční profylaxe * MeSH
• protilátky virové imunologie   škodlivé účinky   terapeutické užití   MeSH
• zvýšená infektivita v přítomnosti protilátek MeSH
• Publikační typ
• práce podpořená grantem MeSH
• přehledy MeSH
• Geografické názvy
• Rusko MeSH

BACKGROUND: Tick-borne encephalitis (TBE) is a severe neuropathological disorder caused by tick-borne encephalitis virus (TBEV). Brain TBEV infection is characterized by extensive pathological neuroinflammation. The mechanism by which TBEV causes CNS destruction remains unclear, but growing evidence suggests that it involves both direct neuronal damage by the virus infection and indirect damage caused by the immune response. Here, we aimed to examine the TBEV-infection-induced innate immune response in mice and in human neural cells. We also compared cytokine/chemokine communication between naïve and infected neuronal cells and astrocytes. METHODS: We used a multiplexed Luminex system to measure multiple cytokines/chemokines and growth factors in mouse serum samples and brain tissue, and in human neuroblastoma cells (SK-N-SH) and primary cortical astrocytes (HBCA), which were infected with the highly pathogenic TBEV strain Hypr. We also investigated changes in cytokine/chemokine production in naïve HBCA cells treated with virus-free supernatants from TBEV-infected SK-N-SH cells and in naïve SK-N-SH cells treated with virus-free supernatants from TBEV-infected HBCA cells. Additionally, a plaque assay was performed to assess how cytokine/chemokine treatment influenced viral growth following TBEV infection. RESULTS: TBEV-infected mice exhibited time-dependent increases in serum and brain tissue concentrations of multiple cytokines/chemokines (mainly CXCL10/IP-10, and also CXCL1, G-CSF, IL-6, and others). TBEV-infected SK-N-SH cells exhibited increased production of IL-8 and RANTES and downregulated MCP-1 and HGF. TBEV infection of HBCA cells activated production of a broad spectrum of pro-inflammatory cytokines, chemokines, and growth factors (mainly IL-6, IL-8, CXCL10, RANTES, and G-CSF) and downregulated the expression of VEGF. Treatment of SK-N-SH with supernatants from infected HBCA induced expression of a variety of chemokines and pro-inflammatory cytokines, reduced SK-N-SH mortality after TBEV infection, and decreased virus growth in these cells. Treatment of HBCA with supernatants from infected SK-N-SH had little effect on cytokine/chemokine/growth factor expression but reduced TBEV growth in these cells after infection. CONCLUSIONS: Our results indicated that both neurons and astrocytes are potential sources of pro-inflammatory cytokines in TBEV-infected brain tissue. Infected/activated astrocytes produce cytokines/chemokines that stimulate the innate neuronal immune response, limiting virus replication, and increasing survival of infected neurons.

• MeSH
• cytokiny imunologie   metabolismus   MeSH
• klíšťová encefalitida imunologie   metabolismus   MeSH
• lidé MeSH
• mozek imunologie   metabolismus   patologie   MeSH
• myši MeSH
• neurony imunologie   metabolismus   virologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The adenosine analogue galidesivir (BCX4430), a broad-spectrum RNA virus inhibitor, has entered a phase 1 clinical safety and pharmacokinetics study in healthy subjects and is under clinical development for treatment of Ebola and yellow fever virus infections. Moreover, galidesivir also inhibits the reproduction of tick-borne encephalitis virus (TBEV) and numerous other medically important flaviviruses. Until now, studies of this antiviral agent have not yielded resistant viruses. Here, we demonstrate that an E460D substitution in the active site of TBEV RNA-dependent RNA polymerase (RdRp) confers resistance to galidesivir in cell culture. Galidesivir-resistant TBEV exhibited no cross-resistance to structurally different antiviral nucleoside analogues, such as 7-deaza-2'-C-methyladenosine, 2'-C-methyladenosine, and 4'-azido-aracytidine. Although the E460D substitution led to only a subtle decrease in viral fitness in cell culture, galidesivir-resistant TBEV was highly attenuated in vivo, with a 100% survival rate and no clinical signs observed in infected mice. Furthermore, no virus was detected in the sera, spleen, or brain of mice inoculated with the galidesivir-resistant TBEV. Our results contribute to understanding the molecular basis of galidesivir antiviral activity, flavivirus resistance to nucleoside inhibitors, and the potential contribution of viral RdRp to flavivirus neurovirulence.IMPORTANCE Tick-borne encephalitis virus (TBEV) is a pathogen that causes severe human neuroinfections in Europe and Asia and for which there is currently no specific therapy. We have previously found that galidesivir (BCX4430), a broad-spectrum RNA virus inhibitor, which is under clinical development for treatment of Ebola and yellow fever virus infections, has a strong antiviral effect against TBEV. For any antiviral drug, it is important to generate drug-resistant mutants to understand how the drug works. Here, we produced TBEV mutants resistant to galidesivir and found that the resistance is caused by a single amino acid substitution in an active site of the viral RNA-dependent RNA polymerase, an enzyme which is crucial for replication of the viral RNA genome. Although this substitution led only to a subtle decrease in viral fitness in cell culture, galidesivir-resistant TBEV was highly attenuated in a mouse model. Our results contribute to understanding the molecular basis of galidesivir antiviral activity.

• MeSH
• adenin analogy a deriváty   chemie   farmakologie   MeSH
• alely MeSH
• antibiotická rezistence MeSH
• antivirové látky chemie   farmakologie   MeSH
• buněčné linie MeSH
• genotyp MeSH
• klíšťová encefalitida farmakoterapie   virologie   MeSH
• modely nemocí na zvířatech MeSH
• mutace * MeSH
• myši MeSH
• pyrrolidiny chemie   farmakologie   MeSH
• substituce aminokyselin * MeSH
• virová léková rezistence * MeSH
• virové nestrukturální proteiny genetika   MeSH
• viry klíšťové encefalitidy účinky léků   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Tick-borne encephalitis (TBE) is an illness caused by tick-borne encephalitis virus (TBEV) infection which is often limited to a febrile illness, but may lead to very aggressive downstream neurological manifestations. The disease is prevalent in forested areas of Europe and northeastern Asia, and is typically caused by infection involving one of three TBEV subtypes, namely the European (TBEV-Eu), the Siberian (TBEV-Sib), or the Far Eastern (TBEV-FE) subtypes. In addition to the three main TBEV subtypes, two other subtypes; i.e., the Baikalian (TBEV-Bkl) and the Himalayan subtype (TBEV-Him), have been described recently. In Europe, TBEV-Eu infection usually results in only mild TBE associated with a mortality rate of <2%. TBEV-Sib infection also results in a generally mild TBE associated with a non-paralytic febrile form of encephalitis, although there is a tendency towards persistent TBE caused by chronic viral infection. TBE-FE infection is considered to induce the most severe forms of TBE. Importantly though, viral subtype is not the sole determinant of TBE severity; both mild and severe cases of TBE are in fact associated with infection by any of the subtypes. In keeping with this observation, the overall TBE mortality rate in Russia is ∼2%, in spite of the fact that TBEV-Sib and TBEV-FE subtypes appear to be inducers of more severe TBE than TBEV-Eu. On the other hand, TBEV-Sib and TBEV-FE subtype infections in Russia are associated with essentially unique forms of TBE rarely seen elsewhere if at all, such as the hemorrhagic and chronic (progressive) forms of the disease. For post-exposure prophylaxis and TBE treatment in Russia and Kazakhstan, a specific anti-TBEV immunoglobulin is currently used with well-documented efficacy, but the use of specific TBEV immunoglobulins has been discontinued in Europe due to concerns regarding antibody-enhanced disease in naïve individuals. Therefore, new treatments are essential. This review summarizes available data on the pathogenesis and clinical features of TBE, plus different vaccine preparations available in Europe and Russia. In addition, new treatment possibilities, including small molecule drugs and experimental immunotherapies are reviewed. The authors caution that their descriptions of approved or experimental therapies should not be considered to be recommendations for patient care.

• MeSH
• antivirové látky terapeutické užití   MeSH
• fylogeneze MeSH
• klíšťata virologie   MeSH
• klíšťová encefalitida farmakoterapie   imunologie   prevence a kontrola   MeSH
• lidé MeSH
• myši MeSH
• virové vakcíny imunologie   MeSH
• viry klíšťové encefalitidy imunologie   patogenita   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Geografické názvy
• Evropa MeSH
• Rusko MeSH

Kyasanur Forest disease virus (KFDV) is a highly pathogenic tick-borne flavivirus enzootic to India. In humans, KFDV causes a severe febrile disease. In some infected individuals, hemorrhagic manifestations, such as bleeding from the nose and gums and gastrointestinal bleeding with hematemesis and/or blood in the stool, have been reported. However, the mechanisms underlying these hemorrhagic complications remain unknown, and there is no information about the specific target cells for KFDV. We investigated the interaction of KFDV with vascular endothelial cells (ECs) and monocyte-derived dendritic cells (moDCs), which are key targets for several other hemorrhagic viruses. Here, we report that ECs are permissive to KFDV infection, which leads to their activation, as demonstrated by the upregulation of E-selectin, intercellular adhesion molecule 1, and vascular cell adhesion molecule 1 at the mRNA and protein levels. Increased expression of these adhesive molecules correlated with increased leukocyte adhesion. Infected ECs upregulated the expression of interleukin (IL)-6 but not IL-8. Additionally, moDCs were permissive to KFDV infection, leading to increased release of IL-6 and tumor necrosis factor-α. Supernatants from KFDV-infected moDCs caused EC activation, as measured by leukocyte adhesion. The results indicate that ECs and moDCs can be targets for KFDV and that both direct and indirect mechanisms can contribute to EC activation.

• MeSH
• CD antigeny genetika   imunologie   MeSH
• cévní buněčněadhezivní molekula-1 genetika   imunologie   MeSH
• dendritické buňky imunologie   virologie   MeSH
• endoteliální buňky imunologie   virologie   MeSH
• interleukin-6 genetika   imunologie   MeSH
• interleukin-8 genetika   imunologie   MeSH
• kadheriny genetika   imunologie   MeSH
• kultivované buňky MeSH
• lidé MeSH
• messenger RNA MeSH
• mezibuněčná adhezivní molekula-1 genetika   imunologie   MeSH
• nemoc kyasanurského lesa imunologie   MeSH
• TNF-alfa genetika   imunologie   MeSH
• viry klíšťové encefalitidy imunologie   patogenita   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Nucleoside analogs represent the largest class of small molecule-based antivirals, which currently form the backbone of chemotherapy of chronic infections caused by HIV, hepatitis B or C viruses, and herpes viruses. High antiviral potency and favorable pharmacokinetics parameters make some nucleoside analogs suitable also for the treatment of acute infections caused by other medically important RNA and DNA viruses. This review summarizes available information on antiviral research of nucleoside analogs against arthropod-borne members of the genus Flavivirus within the family Flaviviridae, being primarily focused on description of nucleoside inhibitors of flaviviral RNA-dependent RNA polymerase, methyltransferase, and helicase/NTPase. Inhibitors of intracellular nucleoside synthesis and newly discovered nucleoside derivatives with high antiflavivirus potency, whose modes of action are currently not completely understood, have drawn attention. Moreover, this review highlights important challenges and complications in nucleoside analog development and suggests possible strategies to overcome these limitations.

• MeSH
• antivirové látky chemie   farmakologie   MeSH
• Culicidae virologie   MeSH
• Flavivirus účinky léků   MeSH
• infekce viry z rodu Flavivirus farmakoterapie   virologie   MeSH
• mikrobiální testy citlivosti MeSH
• molekulární struktura MeSH
• nukleosidy chemie   farmakologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH