Remdesivir, Zidovudine (AZT) and Nevirapine inhibit Chandipura virus replication through high energy interactions with the RdRp domain of the polymerase protein L

Chandipura Virus (CHPV), a rhabdovirus belonging to mononegavirales, is an emerging pathogen in Indian subcontinent. The virus infection causes fever, brain encephalitis among the young children below 14 yrs of age. In recent past, several outbreaks and deaths among children were reported from in India. There are no targeted drugs or vaccines available against CHPV and symptomatic treatments are the only option. In this background, we aimed to investigate the inhibitory effects of some priviously known viral RNA polymerase inhibitor drugs on CHPV replication. First, we examined remdesivir, which is known to inhibit HCV, Ebola and SARS-CoV-2 replication and close structural similarity along with conserved residues in the finger region of RNA dependent RNA polymerase (RdRp) domain is the basis of replication inhibition. Our results showed that remdesivir inhibits CHPV replication in vero E6 cells to a significant level. In this study we have also included non-nucleoside anti-retroviral inhibitor (NNRTI) drug nevirapine, and nucleoside inhibitor (NRTI) drug AZT (Zidovudine) to determine if these are also able to inhibit CHPV replication. Interestingly, we observed inhibition of CHPV replication by both nevirapine and AZT (in the order nevirapine>AZT), albeit to a lesser extent compared to remdesivir. We next performed molecular docking and modeling study to get an insight about the interactions of these drugs with CHPV polymerase protein. Modeling study predicts that remdesivir has most favourable CHPV polymerase binding energy among these three drugs. Both remdesivor and AZT binds near the polymerase active site through interctions with residues in finger and palm regions of RdRp. In contrast, nevirapine binds to the N-terminal domain (NTD) of the RdRp. In summary, we found remdesivir as a potent inhibitor of CHPV. A combination therapy including remdesivir, nevirapine and AZT may be a better drug cocktail to treat CHPV disease. Our findings warrant further studies of these drugs against CHPV in animal models for clinical use in near future.