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Antiviral Research (v.90, #2)
Targeting the Flavivirus Helicase
by Eloise Mastrangelo; Margherita Pezzullo; Martino Bolognesi; Suzanne Keptein; Johan Neyts; Boris Pastorino; Xavier de Lambellerie; Mario Milani (pp. a72-a73).
Crimean-Congo hemorrhagic fever: Current and future prospects of vaccines and therapies
by Maryam Keshtkar-Jahromi; Jens H. Kuhn; Iva Christova; Steven B. Bradfute; Peter B. Jahrling; Sina Bavari (pp. 85-92).
Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne disease caused by CCHF virus (CCHFV), a nairovirus in the family Bunyaviridae. CCHF occurs sporadically in a number of countries in Asia, the Middle East, southeastern Europe and Africa. Patients may develop subclinical to severe hemorrhagic disease, with fatal outcomes in a substantial percentage of cases. Transmission usually occurs through contact with viremic livestock or patients or bites by infected ticks. The number of reported cases has increased in recent years, possibly due to global climatic change and human perturbations of biocenoses that may have led to the migration of tick vectors. There is currently no FDA-approved vaccine or specific antiviral therapy for CCHF. The classification of CCHFV as a WHO Risk Group IV pathogen and the lack of suitable animal models has caused progress in developing new prophylactic and therapeutic measures to be slow. Ribavirin is active against CCHFV in vitro, but its efficacy for human therapy has not been definitively demonstrated by clinical studies. CCHF-immunoglobulin is also in use, but without clear evidence of efficacy. In this article, we review the development of prophylaxis and therapy for CCHF and discuss future prospects for vaccine and drug development.
Keywords: Abbreviations; ALT; alanine aminotransferase; CCHF; Crimean-Congo hemorrhagic fever; CCHFV; Crimean-Congo hemorrhagic fever virus; CCL; chemokine (C-C motif) ligand; CFA; complement-fixation assay; ELISA; enzyme-linked immunosorbent assay; FDA; US Food and Drug Administration; IFN; interferon; IL; interleukin; mAb; monoclonal antibody; NIAID; US National Institute of Allergy and Infectious Diseases; PKR; protein kinase R; RT-PCR; reverse transcription polymerase chain reaction; STAT; signal transducer and activator of transcription; TNF; tumor necrosis factor; VLP; virus-like particle; WHO; World Health OrganizationCrimean-Congo hemorrhagic fever; Bunyavirus; Nairovirus; Priority pathogen; Ribavirin; Antiviral therapy; Viral hemorrhagic fever
New opportunities in anti-hepatitis C virus drug discovery: Targeting NS4B
by Roopa Rai; Jerome Deval (pp. 93-101).
Current therapy for chronic hepatitis C virus (HCV) infection constitutes a combination of pegylated interferon alfa-2a or alpha-2b and ribavirin. Although successful for many patient populations, this regimen has numerous limitations, including non-response, relapse, poor tolerability and long duration of treatment. To address these shortcomings, new small molecule agents are advancing in clinical development. Most of the current clinical candidates act by directly inhibiting key enzymes in the viral life-cycle: the NS5B polymerase, or the NS3/4A protease. Less well-studied, the non-structural 4B (NS4B) protein has recently emerged as an alternative target for Direct-acting Antiviral Agents (DAAs). NS4B is a 27-kDa membrane protein that is primarily involved in the formation of membrane vesicles – also named membranous web – used as scaffold for the assembly of the HCV replication complex. In addition, NS4B contains NTPase and RNA binding activities, as well as anti-apoptotic properties. This review summarizes the current understanding of the structure and functions of NS4B, an essential component of the replication machinery of HCV. In this literature and patent review, we report the recent developments in anti-NS4B drug discovery. These advances open the possibility for future combination therapies with other DAAs.
Keywords: Abbreviations; HCV; hepatitis C virus; kDa; kilo Dalton; NS4B; non-structural protein 4B; NTPase; nucleoside triphosphatase; ssRNA; single-stranded RNA; DAA; Direct-acting Antiviral Agent; ER; endoplasmic reticulum; GT; genotype; AH; amphipatic helix; ATP; adenosine triphosphate; ADP; adenosine diphosphate; Arg; arginine; Ala; alanine; Cys; cysteine; GFP; green fluorescent protein; IFN; interferon; UTR; un-translated region; TM; trans-membrane; IRES; internal ribosome entry siteChronic hepatitis C virus; HCV; NS4B; Membranous web; Inhibitor; Clemizole hydrochloride
Arenaviruses and hantaviruses: From epidemiology and genomics to antivirals
by R.N. Charrel; B. Coutard; C. Baronti; B. Canard; A. Nougairede; A. Frangeul; B. Morin; S. Jamal; C.L. Schmidt; R. Hilgenfeld; B. Klempa; X. de Lamballerie (pp. 102-114).
The arenaviruses and hantaviruses are segmented genome RNA viruses that are hosted by rodents. Due to their association with rodents, they are globally widespread and can infect humans via direct or indirect routes of transmission, causing considerable human morbidity and mortality. Nevertheless, despite their obvious and emerging importance as pathogens, there are currently no effective antiviral drugs (except ribavirin which proved effective against Lassa virus) with which to treat humans infected by any of these viruses. The EU-funded VIZIER project (Comparative Structural Genomics of Viral Enzymes Involved in Replication) was instigated with an ultimate view of contributing to the development of antiviral therapies for RNA viruses, including the arenaviruses and bunyaviruses. This review highlights some of the major features of the arenaviruses and hantaviruses that have been investigated during recent years. After describing their classification and epidemiology, we review progress in understanding the genomics as well as the structure and function of replicative enzymes achieved under the VIZIER program and the development of new disease control strategies.
Keywords: Hantavirus; Arenavirus; Zoonosis; Antiviral therapy
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