作者: Yip, Andy ; Duraiswamy, Jeyaraj ; Liu, Boping ; Goh, Anne ; Yin, Zheng ; Keller, Thomas H. ; Qing, Min ; Schul, Wouter ; Dartois, Veronique ; Lakshminarayana, Suresh B. ; Kondreddi, Ravinder Reddi ; Weaver, Margaret ; Shi, Pei-Yong ; Chen, Yen-Liang ; Xu, Hao Ying

ABSTRACT Dengue virus (DENV) is the most prevalent mosquito-borne viral pathogen that infects humans. Neither a vaccine nor an antiviral therapy is currently available for DENV. Here, we report an adenosine nucleoside prodrug that potently inhibits DENV replication both in cell culture and in a DENV mouse model. NITD449 (2′- C -acetylene-7-deaza-7-carbamoyladenosine) was initially identified as a parental compound that inhibits all four serotypes of DENV with low cytotoxicity. However, in vivo pharmacokinetic studies indicated that NITD449 had a low level of exposure in plasma when dosed orally. To increase the oral bioavailability, we covalently linked isobutyric acids to the 3′- and 5′-hydroxyl groups of ribose via ester linkage to NITD449, leading to the prodrug NITD203 (3′,5′- O -diisobutyryl-2′- C -acetylene-7-deaza-7-carbamoyl-adenosin). Pharmacokinetic analysis showed that upon oral dosing of the prodrug, NITD203 was readily converted to NITD449, resulting in improved exposure of the parental compound in plasma in both mouse and rat. In DENV-infected AG129 mice, oral dosing of the prodrug at 25 mg/kg of body weight reduced peak viremia by 30-fold. Antiviral spectrum analysis showed that NITD203 inhibited various flaviviruses (DENV, yellow fever virus, and West Nile virus) and hepatitis C virus but not Chikungunya virus (an alphavirus). Mode-of-action analysis, using a luciferase-reporting replicon, indicated that NITD203 inhibited DENV RNA synthesis. Although NITD203 exhibited potent in vitro and in vivo efficacies, the compound could not reach a satisfactory no-observable-adverse-effect level (NOAEL) in a 2-week in vivo toxicity study. Nevertheless, our results demonstrate that a prodrug approach using a nucleoside analog could potentially be developed for flavivirus antiviral therapy.

PeerJ3区 · 生物学

Using bioinformatics tools for the discovery of Dengue RNA-dependent RNA polymerase inhibitors

3区 · 生物学

ArticleOA

作者: Ramharack, Pritika ; Soliman, Mahmoud E S ; Nncube, Nomagugu B

BackgroundDengue fever has rapidly manifested into a serious global health concern. The emergence of various viral serotypes has prompted the urgent need for innovative drug design techniques. Of the viral non-structural enzymes, the NS5 RNA-dependent RNA polymerase has been established as a promising target due to its lack of an enzymatic counterpart in mammalian cells and its conserved structure amongst all serotypes. The onus is now on scientists to probe further into understanding this enzyme and its mechanism of action. The field of bioinformatics has evolved greatly over recent decades, with updated drug design tools now being publically available.MethodsIn this study, bioinformatics tools were used to provide a comprehensive sequence and structural analysis of the two most prominent serotypes of Dengue RNA-dependent RNA polymerase. A list of popularflavivirusinhibitors were also chosen to dock to the active site of the enzyme. The best docked compound was then used as a template to generate a pharmacophore model that may assist in the design of target-specific Dengue virus inhibitors.ResultsComparative sequence alignment exhibited similarity between all three domains of serotype 2 and 3.Sequence analysis revealed highly conserved regions at residues Meth530, Thr543 Asp597, Glu616, Arg659 and Pro671. Mapping of the active site demonstrated two highly conserved residues: Ser710 and Arg729. Of the active site interacting residues, Ser796 was common amongst all ten docked compounds, indicating its importance in the drug design process. Of the ten dockedflavivirusinhibitors, NITD-203 showed the best binding affinity to the active site. Further pharmacophore modeling of NITD-203 depicted significant pharmacophoric elements that are necessary for stable binding to the active site.DiscussionThis study utilized publically available bioinformatics tools to provide a comprehensive framework on Dengue RNA-dependent RNA polymerase. Based on docking studies, a pharmacophore model was also designed to unveil the crucial pharmacophoric elements that are required when constructing an efficacious DENV inhibitor. We believe that this study will be a cornerstone in paving the road toward the design of target-specific inhibitors against DENV RdRp.

100 项与 NITD-203 相关的药物交易

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