The research described in this thesis aimed focused on CHIKV replication and on the identification of much-needed inhibitors of CHIKV infection. Following the development of an in vitro assay to... Show moreThe research described in this thesis aimed focused on CHIKV replication and on the identification of much-needed inhibitors of CHIKV infection. Following the development of an in vitro assay to study CHIKV replication, this tool was used to characterize the mode of action (MoA) of antiviral compounds and suramin was identified as a potent inhibitor of viral RNA synthesis. However, we discovered that in cell culture, suramin’s antiviral activity was mainly due to inhibition of CHIKV binding/entry, and to a lesser extent of virus release. Suramin was also found to inhibit binding/entry and virion biogenesis of Zika virus (ZIKV), a recently emerged flavivirus. Due to its ability to form electrostatic interactions with positive charges on proteins, suramin may block the contact between virions and their (co)receptors, by interacting with either virus or receptor, or with both. Using radioactively-labelled suramin, it was clearly shown that the compound interacts with CHIKV particles, more specifically with their envelope proteins. Additionally, suramin could interfere with cell attachment and/or the structural changes required for fusion. Suramin-resistant CHIKV variants were selected, which contained mutations in the E2 envelope protein (involved in receptor interactions), supporting the idea that suramin blocks the early steps of the infectious cycle. Show less
