Bispidine-Amino Acid Conjugates Act as a Novel Scaffold for the Design of Antivirals That Block Japanese Encephalitis Virus Replication

Abstract

BackgroundJapanese encephalitis virus (JEV) is a major cause of viral encephalitis in South and South-East Asia. Lack of antivirals and non-availability of affordable vaccines in these endemic areas are a major setback in combating JEV and other closely related viruses such as West Nile virus and dengue virus. Protein secondary structure mimetics are excellent candidates for inhibiting the protein-protein interactions and therefore serve as an attractive tool in drug development. We synthesized derivatives containing the backbone of naturally occurring lupin alkaloid, sparteine, which act as protein secondary structure mimetics and show that these compounds exhibit antiviral properties.Methodology/Principal FindingsIn this study we have identified 3,7-diazabicyclo[3.3.1]nonane, commonly called bispidine, as a privileged scaffold to synthesize effective antiviral agents. We have synthesized derivatives of bispidine conjugated with amino acids and found that hydrophobic amino acid residues showed antiviral properties against JEV. We identified a tryptophan derivative, Bisp-W, which at 5 µM concentration inhibited JEV infection in neuroblastoma cells by more than 100-fold. Viral inhibition was at a stage post-entry and prior to viral protein translation possibly at viral RNA replication. We show that similar concentration of Bisp-W was capable of inhibiting viral infection of two other encephalitic viruses namely, West Nile virus and Chandipura virus.Conclusions/SignificanceWe have demonstrated that the amino-acid conjugates of 3,7-diazabicyclo[3.3.1]nonane can serve as a molecular scaffold for development of potent antivirals against encephalitic viruses. Our findings will provide a novel platform to develop effective inhibitors of JEV and perhaps other RNA viruses causing encephalitis.

Adaptor protein complexes-1 and 3 are involved at distinct stages of flavivirus life-cycle

“…All cell lines and their growth conditions have been described before1027. Porcine kidney (PS) cells, Vero and BHK-21 cells were grown in the minimal essential medium (MEM) containing 10% FBS, Earl's salts and antibiotics.…”

Japanese Encephalitis Virus Disrupts Cell-Cell Junctions and Affects the Epithelial Permeability Barrier Functions

“…We have recently identified amino acid conjugates of 3,7-diazabicyclo[3.3.1]nonane, commonly called bispidine (Bisp-W), as novel inhibitor of JEV replication [18]. To identify if JEV replication is required for TER disruption, caco-2 cells were infected with JEV and Bisp-W was added at 1 h p.i.…”

“…Human umbilical vein endothelial cells (HUVEC) were purchased from BD Biosciences and grown in endothelial cell culture medium supplied with the cell line. JEV-Vellore strain was used throughout the study and viral titers were estimated as described previously [18]. For generation of virus-free culture supernatants, Caco2 cells were infected with JEV at an MOI of 5 pfu/cell and at around 44 hour post-infection (h pi) supernatants were collected and clarified through Amicon columns with 100 k Da cut-off (Merck-Millipore).…”

Japanese Encephalitis, Recent Perspectives on Virus Genome, Transmission, Epidemiology, Diagnosis and Prophylactic Interventions

“…Supportive care directed to control convulsions and maintenance of airway, fluid and electrolyte balance plays a key role in treatment efficacy during the acute phase. Although, treatment with diethyldithiocarbamate (Saxena et al, 2003), Lipid-complexed small interfering RNA (siRNA) (Kumar et al, 2006), Rosmarinic acid (Swarup et al, 2007), Pentoxifylline (Sebastian et al, 2009), Arctigenin (a lignin derived from the Greater Burdock (Arctiumlappa) (Hayashi, 2010), Peptideconjugated phosphorodiamidatemorpholino oligomers (Anantpadma et al, 2010), Minocycline (semi-synthetic derivative of tetracycline) (Dutta & Basu, 2011), Tilapia hepcidin 1-5 (Antimicrobial peptide) (Huang et al, 2011), Griffithsin (Ishag et al, 2013), Bispidine (amino acid conjugate of 3,7-diazabicyclononane) (Haridas et al, 2013), Mycophenolic acid (Sebastian et al, 2011), Luteolin (Fan et al, 2016 and anti-miR301a therapy (Hazra et al, 2017) have been found as promising candidates against JE infection that were attempted and showed protective effect in laboratory models. Their efficacy in the hospital settings is a big challenge which needs further assessment and increased availability to the needful.…”