Inhibition of HIV‐1 by a Peptide Ligand of the Genomic RNA Packaging Signal Ψ

Abstract

The interaction of the nucleocapsid NCp7 of the human immunodeficiency virus type 1 (HIV-1) Gag polyprotein with the RNA packaging signal Psi ensures specific encapsidation of the dimeric full length viral genome into nascent virus particles. Being an essential step in the HIV-1 replication cycle, specific genome encapsidation represents a promising target for therapeutic intervention. We previously selected peptides binding to HIV-1 Psi-RNA or stem loops (SL) thereof by phage display. Herein, we describe synthesis of peptide variants of the consensus HWWPWW motif on membrane supports to optimize Psi-RNA binding. The optimized peptide, psi-pepB, was characterized in detail with respect to its conformation and binding properties for the SL3 of the Psi packaging signal by NMR and tryptophan fluorescence quenching. Functional analysis revealed that psi-pepB caused a strong reduction of virus release by infected cells as monitored by reduced transduction efficiencies, capsid p24 antigen levels, and electron microscopy. Thus, this peptide shows antiviral activity and could serve as a lead compound to develop new drugs targeting HIV-1.

Flexible Nature and Specific Functions of the HIV-1 Nucleocapsid Protein

“…The methylated oligoribonucleotides appear particularly promising, since their intracellular delivery using a cell-penetrating peptide was found to completely impede HIV-1 replication in primary human cells at sub-nanomolar concentrations. Finally, small peptides or peptidomimetics [156][157][158][159] able to compete with NCp7 for its NA binding, and chaperoning activities were designed. However, these peptides were found to be active only in the micromolar range.…”

Advances in targeting nucleocapsid–nucleic acid interactions in HIV-1 therapy

“…A continuing strategy has been to identify peptides, oligonucleotides, or compounds that disrupt the interaction of viral RNA to NC. Some of the initial efforts to identify agents that disrupted viral RNA binding to NC, and thus functioned as antivirals, resulted in the identification of peptides (Dietz et al, 2008; Park et al, 2004; Pustowka et al, 2003), cyclic peptides (Druillennec et al, 1999), antisense oligonucleotides (Elmen et al, 2004) and aminoglycosides (Turner et al, 2006b). More recently, virtual and high-throughput screening identified 4 compounds, 14 - 17 (Fig 5), which bound to SL3 (the packaging signal Psi) and inhibited SL3-NC complex formation (Warui and Baranger, 2009; Warui and Baranger, 2012).…”

HIV-1 Gag as an Antiviral Target: Development of Assembly and Maturation Inhibitors

“…TAR has been targeted using anthraquinone compounds in in vitro studies [142]. A variety of peptides that disrupt viral binding to NC have been reported [143–146]. These studies seem to establish that the NC-psi RNA interaction can be specifically inhibited, but these efforts have not progressed past early preclinical proof-of-concept studies.…”