A Phenotypic Assay to Identify Chikungunya Virus Inhibitors Targeting the Nonstructural Protein nsP2

1Institut Pasteur, Unité de Génomique Virale et Vaccination, Paris, France.
Journal of Biomolecular Screening (Impact Factor: 2.42). 09/2012; 18(2). DOI: 10.1177/1087057112460091
Source: PubMed


Chikungunya virus (CHIKV) is a mosquito-transmitted pathogen responsible for an acute infection of abrupt onset, characterized by high fever, polyarthralgia, myalgia, headaches, chills, and rash. In 2006, CHIKV was responsible for an epidemic outbreak of unprecedented magnitude in the Indian Ocean, stressing the need for therapeutic approaches. Since then, we have acquired a better understanding of CHIKV biology, but we are still missing active molecules against this reemerging pathogen. We recently reported that the nonstructural nsP2 protein of CHIKV induces a transcriptional shutoff that allows the virus to block cellular antiviral response. This was demonstrated using various luciferase-based reporter gene assays, including a trans-reporter system where Gal4 DNA binding domain is fused to Fos transcription factor. Here, we turned this assay into a high-throughput screening system to identify small molecules targeting nsP2-mediated shutoff. Among 3040 molecules tested, we identified one natural compound that partially blocks nsP2 activity and inhibits CHIKV replication in vitro. This proof of concept suggests that similar functional assays could be developed to target other viral proteins mediating a cellular shutoff and identify innovative therapeutic molecules.

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    • "Recently, cell-based high throughput assays have been developed to identify potential CHIKV inhibitors. One study reported a focus screen of 356 natural compounds and clinically approved drugs using a CHIKV replicon and a concomitant screen with SFV surrogate infection model [66], while another study screened 3,040 small molecules for inhibitors of CHIKV nsP2 using a novel target-based phenotypic assay approach [67]. Cruz et al. [68] used a cell-based high throughput screening assay using resazurin against a kinase inhibitor library combined with the image-based high content assay approach to identify compounds against CHIKV having novel antiviral activity. "
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