744
HIV-1 Inhibition with Multi-valent Gold Nanoparticles
Mary Catherine Bowman*1, E Ballard2, C Akerson2, J D'Antonio2, D Feldheim3, C Melander2, and D Margolis1
1Univ of North Carolina at Chapel Hill, US; 2North Carolina State Univ, Raleigh, US; and 3Univ of Colorado, Boulder, US
Background: Protein–protein interactions are difficult to
target with the current small molecule therapeutics, as most protein surfaces
lack discrete, high affinity molecular recognition sites. We hypothesized that
the use of mono-disperse, drug-coated gold nanoparticles (NP) could disrupt
protein/protein interactions due to comparable size and an ability to present
multiple binding ligands. As proof of principle we tested the ability of a gold
nanoparticles to restore the antiviral activity of an inactive CCR5 inhibitor.
Methods: An inactive CCR5 inhibitor (ΔTak) was
generated by removal of the piperidine group from TAK-779, a validated CCR5
inhibitor. This molecule was covalently conjugated to a 2-nm monodisperse, gold
nanoparticle at a ratio of 10:1 [ΔTAK(10)–NP], where the nanoparticles replaced
the piperdine group. A glutathione (GSH) conjugated nanoparticle served as a
negative control. Phytohemagglutinin-stimulated peripheral blood mononuclear
cells (PBMC) were infected with the CCR5-tropic JR-CSF strain that is relatively
insensitive to TAK-779. p24 antigen production in the presence or absence of
inhibitors was measured by enzyme-linked immunosorbent assay (ELISA) on day 7.
Experiments were performed in triplicate.
Results: TAK-779 inhibited replication of JR-CSF with an IC50
~10 nM. ΔTAK and GSH–NP were inactive. Conjugation of the ΔTAK to
gold nanoparticles (ΔTAK(10)–NP) restored activity to levels nearing that
of TAK-779. Thus the gold nanoparticle alone is not responsible for the
antiviral activity of ligand conjugated nanoparticles.
Conclusions: In this proof-of principle experiment, we
report that the first application of mono-disperse gold nanoparticles as a base
scaffold for inhibition of HIV infection. This method may allow mixed ligand
nanoparticles to target intracellular protein/protein interactions that are key
for the HIV life cycle (e.g., Vif) with inhibitors that otherwise cannot access
the intracellular space, or drug delivery to anatomic spaces (e.g., CNS) or
selected cell types that are currently inadequately accessed by small molecule
therapeutics.
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