Dengue Virus Capsid Protein Binding to Lipid Droplets and its Inhibition. towards a New Drug Target

Dengue virus (DENV) affects millions of people, causing more than 20,000 deaths yearly. No effective treatment is currently available, partially due to the lack of knowledge on the basic aspects of the viral life cycle. Here, we characterized the properties of the interaction between the DENV capsid (C) protein and hepatic lipid droplets (LDs), which was recently shown to be essential for viral replication. Atomic force microscopy (AFM)-based force spectroscopy measurements were performed with DENV C-functionalized AFM tips. DENV C-LDs interaction was found to be strong and dependent on the high intracellular potassium concentration. Inhibition of Na+/K+-ATPase in DENV-infected cells resulted in the dissociation of DENV C from LDs and a 50-fold inhibition of infectious virus production (but not of RNA replication), demonstrating the biological relevance of the K+-dependence. Limited LDs proteolysis impaired DENV C-LDs interaction, and force measurements in the presence of specific antibodies indicated that perilipin 3 (TIP47) is the major DENV C ligand on the LDs surface. A peptide based on a conserved segment of DENV C intrinsically disordered N-terminal domain (pep14-23) was shown by force spectroscopy to successfully inhibit DENV C-LDs interaction. These advances pave the way to drug development approaches, in which inhibitory efficiency may be improved through lead optimization. A similar strategy may be used for other flaviviruses.Carvalho et al. (2012) J. Virol., 86, 2096-2108.Martins et al. (2012) Biochem. J., 444, 405-415.