An integrative and multiscale approach to study dengue virus-like particle dynamics.

Abstract

Dengue virus is an enveloped virus which infects millions of people worldwide. The only available vaccine has low efficacy and is recommended only for individuals with prior dengue infection. Virus-like particles (VLPs) are promising platforms as vaccine candidates due to their non-infectious and highly immunogenic nature. These particles lack a genomic core and are highly unstable and heterogeneous in size. This motivates the characterization of the biophysical and structural properties of VLPs to facilitate the rational production of stable and homogenous particles. Dengue VLPs elicits neutralizing antibodies similar to infectious virions. Dengue VLPs are enveloped particles in which sixty envelope (E) and membrane (M) proteins are embedded in a lipid vesicle. Similarly, to the dengue virus, the VLPs undergo a maturation process, involving large conformational changes, leading to exposure of epitopes that subsequently determine the immune response. In this work, the structure and intrinsic dynamics of VLPs and their conformational transitions were investigated using integrative modeling and molecular simulations. To gain atomistic insights into the maturation process and to facilitate the development of stable enveloped VLPs, we employed an integrative approach combining multiscale modeling and simulations with experimental data from cryo-electron microscopy, lipidomics, and secretion assays. Coarse-grained simulations of mature and immature VLPs revealed the effective number of lipids that result in optimally stable and spherical particles. Furthermore, these models were used as a platform to simulate the transition between conformational states in order to understand the maturation process in unprecedented detail. Finally, atomistic MD simulations performed on native dengue and dengue-Japanese encephalitis virus chimeric E/M proteins and their mutants highlighted the role of protein-lipid interactions in governing VLP stability. This integrative approach aims towards the future development of stable and immunogenic next-generation vaccines.