An RNA-binding compound that stabilizes the HIV-1 gRNA packaging signal structure and specifically blocks HIV-1 RNA encapsidation.

Retrovirology 2018 03 14;15(1):25. Epub 2018 Mar 14.

Department of Medicine, University of Cambridge, Addenbrookes Hospital, Box 157, Level 5, Hills Rd, Cambridge, CB2 0QQ, UK.

Background: NSC260594, a quinolinium derivative from the NCI diversity set II compound library, was previously identified in a target-based assay as an inhibitor of the interaction between the HIV-1 (ψ) stem-loop 3 (SL3) RNA and Gag. This compound was shown to exhibit potent antiviral activity. Here, the effects of this compound on individual stages of the viral lifecycle were examined by qRT-PCR, ELISA and Western blot, to see if its actions were specific to the viral packaging stage. The structural effects of NSC260594 binding to the HIV-1 gRNA were also examined by SHAPE and dimerization assays.

Results: Treatment of cells with NSC260594 did not reduce the number of integration events of incoming virus, and treatment of virus producing cells did not affect the level of intracellular Gag protein or viral particle release as determined by immunoblot. However, NSC260594 reduced the incorporation of gRNA into virions by up to 82%, without affecting levels of gRNA inside the cell. This reduction in packaging correlated closely with the reduction in infectivity of the released viral particles. To establish the structural effects of NSC260594 on the HIV-1 gRNA, we performed SHAPE analyses to pinpoint RNA structural changes. NSC260594 had a stabilizing effect on the wild type RNA that was not confined to SL3, but that was propagated across the structure. A packaging mutant lacking SL3 did not show this effect.

Conclusions: NSC260594 acts as a specific inhibitor of HIV-1 RNA packaging. No other viral functions are affected. Its action involves preventing the interaction of Gag with SL3 by stabilizing this small RNA stem-loop which then leads to stabilization of the global packaging signal region (psi or ψ). This confirms data, previously only shown in analyses of isolated SL3 oligonucleotides, that SL3 is structurally labile in the presence of Gag and that this is critical for the complete psi region to be able to adopt different conformations. Since replication is otherwise unaffected by NSC260594 the flexibility of SL3 appears to be a unique requirement for genome encapsidation and identifies this process as a highly specific drug target. This study is proof of principle that development of a new class of antiretroviral drugs that specifically target viral packaging by binding to the viral genomic RNA is achievable.

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12977-018-0407-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5853050PMC
March 2018
10 Reads

Publication Analysis

Top Keywords

hiv-1 grna
12
effects nsc260594
8
structural effects
8
hiv-1 rna
8
nsc260594
8
viral packaging
8
packaging signal
8
sl3
7
viral
7
packaging
7
rna
7
hiv-1
6
grna
5
pinpoint rna
4
confined sl3
4
rna confined
4
type rna
4
wild type
4
sl3 propagated
4
structural changes
4

References

(Supplied by CrossRef)

C Tang et al.
J Mol Biol 2003

J Tang et al.
Bioorg Med Chem Lett 2017

CS Adamson et al.
Retrovirology 2010

P Spearman et al.
Curr Top Med Chem 2016

AA Waheed et al.
AIDS Res Hum Retroviruses 2012

NM Bell et al.
Biochemistry 2012

AM Lever et al.
Adv Pharmacol 2007

NM Bell et al.
Biochemistry 2013

C Hellmund et al.
Viruses 2016

M Brecher et al.
PLoS Pathogens 2017

Similar Publications