Development of a robust cell-based high-throughput screening assay to identify targets of HIV-1 viral protein R dimerization.

Targeting protein-protein interactions (PPI) is an emerging field in drug discovery. Dimerization and PPI are essential properties of human immunodeficiency virus (HIV)-1 proteins, their mediated functions, and virus biology. Additionally, dimerization is required for the functional interaction of HIV-1 proteins with many host cellular components. In this study, a bimolecular fluorescence complementation (BiFC)-based screening assay was developed that can quantify changes in dimerization, using HIV-1 viral protein R (Vpr) dimerization as a "proof of concept." Results demonstrated that Venus Vpr (generated by BiFC Vpr constructs) could be competed off in a dose-dependent manner using untagged, full-length Vpr as a competitor molecule. The change in signal intensity was measured quantitatively through flow cytometry and fluorescence microscopy in a high content screening assay. High content imaging was used to screen a library of small molecules for an effect on Vpr dimerization. Among the tested molecules, a few of the small molecules demonstrate an effect on Vpr dimerization in a dose-dependent manner.

Comparative expression profile of miRNA and mRNA in primary peripheral blood mononuclear cells infected with human immunodeficiency virus (HIV-1).

Host cells respond to exogenous infectious agents such as viruses, including HIV-1. Studies have evaluated the changes associated with virus infection at the transcriptional and translational levels of the cellular genes involved in specific pathways. While this approach is useful, in our view it provides only a partial view of genome-wide changes. Recently, technological advances in the expression profiling at the microRNA (miRNA) and mRNA levels have made it possible to evaluate the changes in the components of multiple pathways. To understand the role of miRNA and its interplay with host cellular gene expression (mRNA) during HIV-1 infection, we performed a comparative global miRNA and mRNA microarray using human PBMCs infected with HIV-1. The PBMCs were derived from multiple donors and were infected with virus generated from the molecular clone pNL4-3. The results showed that HIV-1 infection led to altered regulation of 21 miRNAs and 444 mRNA more than 2-fold, with a statistical significance of p<0.05. Furthermore, the differentially regulated miRNA and mRNA were shown to be associated with host cellular pathways involved in cell cycle/proliferation, apoptosis, T-cell signaling, and immune activation. We also observed a number of inverse correlations of miRNA and mRNA expression in infected PBMCs, further confirming the interrelationship between miRNA and mRNA regulation during HIV-1 infection. These results for the first time provide evidence that the miRNA profile could be an early indicator of host cellular dysfunction induced by HIV-1.