Role of Human Hypoxanthine Guanine Phosphoribosyltransferase in Activation of the Antiviral Agent T-705 (Favipiravir)

Naesens, Lieve; Guddat, L.W.; Keough, Dianne T.; Kuilenburg, André B. P.; Meijer, Judith; Voorde, Johan Vande; Balzarini, Jan

doi:10.1124/mol.113.087247

Cited by 108 publications

(161 citation statements)

References 53 publications

(69 reference statements)

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“…T-705 is converted intracellularly into its T-705-RTP form, which behaves as a pseudopurine (21,22). Consequently, incorporation of T-705-RTP into the viral RNA by the RdRp may possibly lead to chain termination or lethal mutagenesis.…”

Section: Figmentioning

confidence: 99%

Understanding the Mechanism of the Broad-Spectrum Antiviral Activity of Favipiravir (T-705): Key Role of the F1 Motif of the Viral Polymerase

Abdelnabi

Morais

Leyssen

et al. 2017

J Virol

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Favipiravir (T-705) is a broad-spectrum antiviral agent that has been approved in Japan for the treatment of influenza virus infections. T-705 also inhibits the replication of various RNA viruses, including chikungunya virus (CHIKV). We demonstrated earlier that the K291R mutation in the F1 motif of the RNA-dependent RNA polymerase (RdRp) of CHIKV is responsible for low-level resistance to T-705. Interestingly, this lysine is highly conserved in the RdRp of positive-sense singlestranded RNA (ϩssRNA) viruses. To obtain insights into the unique broad-spectrum antiviral activity of T-705, we explored the role of this lysine using another ϩssRNA virus, namely, coxsackievirus B3 (CVB3). Introduction of the corresponding K-to-R substitution in the CVB3 RdRp (K159R) resulted in a nonviable virus. Replication competence of the K159R variant was restored by spontaneous acquisition of an A239G substitution in the RdRp. A mutagenesis analysis at position K159 identified the K159M variant as the only other viable variant which had also acquired the A239G substitution. The K159 substitutions markedly decreased the processivity of the purified viral RdRp, which was restored by the introduction of the A239G mutation. The K159R A239G and K159M A239G variants proved, surprisingly, more susceptible than the wild-type virus to T-705 and exhibited lower fidelity in polymerase assays. Furthermore, the K159R A239G variant was found to be highly attenuated in mice. We thus demonstrate that the conserved lysine in the F1 motif of the RdRp of ϩssRNA viruses is involved in the broad-spectrum antiviral activity of T-705 and that it is a key amino acid for the proper functioning of the enzyme.IMPORTANCE In this study, we report the key role of a highly conserved lysine residue of the viral polymerase in the broad-spectrum antiviral activity of favipiravir (T-705) against positive-sense single-stranded RNA viruses. Substitutions of this conserved lysine have a major negative impact on the functionality of the RdRp. Furthermore, we show that this lysine is involved in the fidelity of the RdRp and that the RdRp fidelity influences the sensitivity of the virus for the antiviral efficacy of T-705. Consequently, these results provide insights into the mechanism of the antiviral activity of T-705 and may lay the basis for the design of novel chemical scaffolds that may be endowed with a more potent broad-spectrum antiviral activity than that of T-705.KEYWORDS favipiravir, fidelity, mutagenesis, RdRp, CVB3

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Section: Figmentioning

confidence: 99%

Understanding the Mechanism of the Broad-Spectrum Antiviral Activity of Favipiravir (T-705): Key Role of the F1 Motif of the Viral Polymerase

Abdelnabi

Morais

Leyssen

et al. 2017

J Virol

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“…To analyze differences between two conditions, the unpaired two-sided Student t test was used, setting a P value of Յ0.05 as the cutoff for statistical significance. (Table 1) and a previous study (24). Importantly, in each of these investigations, T-705 was devoid of cytotoxicity at the highest concentration tested, i.e., 600 M (Table 1), 1,000 M (25), or 6,400 M (10).…”

Section: Virusmentioning

confidence: 99%

“…Inside the host cells, T-705 and ribavirin undergo conversion to their ribosyl-5=-mono-, di-, and triphosphate metabolites (23). The high doses required for T-705 (on the order of 800 to 2,400 mg per day) could, at least partially, be related to low efficiency of its metabolic activation (24). Two structural elements are shared by the ribosyl-5=-triphosphate forms of T-705 (T-705-RTP) and ribavirin (RBV-TP).…”

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confidence: 99%

Distinct Effects of T-705 (Favipiravir) and Ribavirin on Influenza Virus Replication and Viral RNA Synthesis

Vanderlinden

Vrancken

Houdt

et al. 2016

Antimicrob Agents Chemother

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100

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c T-705 (favipiravir) is a new antiviral agent in advanced clinical development for influenza therapy. It is supposed to act as an alternative substrate for the viral polymerase, causing inhibition of viral RNA synthesis or virus mutagenesis. These mechanisms were also proposed for ribavirin, an established and broad antiviral drug that shares structural similarity with T-705. We here performed a comparative analysis of the effects of T-705 and ribavirin on influenza virus and host cell functions. Influenza virusinfected cell cultures were exposed to T-705 or ribavirin during single or serial virus passaging. The effects on viral RNA synthesis and infectious virus yield were determined and mutations appearing in the viral genome were detected by whole-genome virus sequencing. In addition, the cellular nucleotide pools as well as direct inhibition of the viral polymerase enzyme were quantified. We demonstrate that the anti-influenza virus effect of ribavirin is based on IMP dehydrogenase inhibition, which results in fast and profound GTP depletion and an imbalance in the nucleotide pools. In contrast, T-705 acts as a potent and GTP-competitive inhibitor of the viral polymerase. In infected cells, viral RNA synthesis is completely inhibited by T-705 or ribavirin at >50 M, whereas exposure to lower drug concentrations induces formation of noninfectious particles and accumulation of random point mutations in the viral genome. This mutagenic effect is 2-fold higher for T-705 than for ribavirin. Hence, T-705 and ribavirin both act as purine pseudobases but profoundly differ with regard to the mechanism behind their antiviral and mutagenic effects on influenza virus.

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“…Intracellular host enzymes act upon T-705, converting it to its active form, T-705-4-ribofuranosyl-5-triphosphate (T-705RTP) (20). T-705RTP functions as a purine nucleotide analog that selectively inhibits the RNA-dependent RNA polymerase (RdRp) or causes lethal mutagenesis upon incorporation into the viral RNA (21)(22)(23)(24).…”

mentioning

confidence: 99%

Antiviral Activity of Favipiravir (T-705) against a Broad Range of Paramyxoviruses In Vitro and against Human Metapneumovirus in Hamsters

Jochmans

Nieuwkoop

Smits

et al. 2016

Antimicrob Agents Chemother

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T he family Paramyxoviridae contains a number of viruses causing respiratory tract illnesses in humans, which together have a large clinical impact (1). Human metapneumovirus (HMPV), respiratory syncytial virus (RSV), and parainfluenza virus (PIV) infections are responsible for severe acute respiratory illnesses mainly in young children, but also in immunocompromised and elderly individuals, and are-together with the influenza viruses (family Orthomyxoviridae)-the primary viral causes of hospitalizations for severe respiratory tract disease (2-5). No licensed vaccines or effective antiviral treatments are available for these viruses. Measles virus, yet another paramyxovirus, is responsible for a devastating disease which the WHO committed to eradicate with the aid of effective vaccines. However, due to suboptimal immunization levels, resurgences in infections have been detected, and there is no effective antiviral treatment available for measles virusinfected patients (6-8). Paramyxoviruses are well known for their zoonotic potential: avian pneumovirus (AMPV) is the proposed avian ancestor of HMPV, and the avian Newcastle disease virus (NDV) can cause disease-primarily conjunctivitis-in humans (9-11). Multiple novel paramyxoviruses have been detected in bats, including close relatives of human viruses (12, 13), and henipaviruses continue to cause infections in humans in . No licensed vaccines or effective antiviral treatments are available for any of these viruses. The continuous burden of disease associated with human and zoonotic paramyxoviruses argues for the development of antiviral therapies with broad-spectrum activity against all paramyxoviruses.Favipiravir (T-705; 6-fluoro-3-hydroxy-2-pyrazinecarboxamine) is a pyrazine derivative that has demonstrated potent antiviral activity against multiple RNA viruses (18,19). Intracellular host enzymes act upon T-705, converting it to its active form, T-705-4-ribofuranosyl-5-triphosphate (T-705RTP) (20). T-705RTP functions as a purine nucleotide analog that selectively inhibits the RNA-dependent RNA polymerase (RdRp) or causes lethal mutagenesis upon incorporation into the viral RNA (21-24). T-705 is presently in clinical development as an influenza virus inhibitor in Japan (new drug application filed) and the United States (phase 3 clinical trial) (18). Antiviral activity has been demonstrated against a broad range of negative-strand RNA viruses, such as members of the Picorna-, , and positive-strand RNA viruses, such as the Noro-and Flavivirus genera (31, 32). Here we evaluated the activity of T-705 against a broad range of paramyxoviruses in vitro and against HMPV in hamsters. MATERIALS AND METHODS Cells

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Role of Human Hypoxanthine Guanine Phosphoribosyltransferase in Activation of the Antiviral Agent T-705 (Favipiravir)

Cited by 108 publications

References 53 publications

Understanding the Mechanism of the Broad-Spectrum Antiviral Activity of Favipiravir (T-705): Key Role of the F1 Motif of the Viral Polymerase

Understanding the Mechanism of the Broad-Spectrum Antiviral Activity of Favipiravir (T-705): Key Role of the F1 Motif of the Viral Polymerase

Distinct Effects of T-705 (Favipiravir) and Ribavirin on Influenza Virus Replication and Viral RNA Synthesis

Antiviral Activity of Favipiravir (T-705) against a Broad Range of Paramyxoviruses In Vitro and against Human Metapneumovirus in Hamsters

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