Native oligodeoxynucleotides specifically active against human immunodeficiency virus type 1 in vitro: a...

Area of Science:

• Molecular Biology
• Virology
• Oligonucleotide Therapeutics

Background:

• Human immunodeficiency virus type 1 (HIV-1) remains a significant global health challenge.
• Developing effective and non-toxic antiviral therapies is crucial for managing HIV-1 infection.
• Oligodeoxynucleotides (ODNs) are being explored as potential antiviral agents.

Purpose of the Study:

• To investigate the antiviral activity of unmodified phosphodiester oligodeoxynucleotides (PO-ODNs) against HIV-1.
• To elucidate the mechanism of action and structure-activity relationships of potent HIV-1 inhibitory PO-ODNs.

Main Methods:

• Synthesis and testing of a series of PO-ODNs complementary to HIV-1 regulatory genes, particularly the vpr gene.
• Evaluation of antiviral activity in de novo infected MT-4 and C8166 cell lines.
• Cytotoxicity assays on uninfected cells.
• Inhibition assays for HIV-1 reverse transcriptase and cell fusion.
• Delayed addition experiments to determine the stage of viral replication targeted.
• Structure-activity relationship studies and physical characterization of active ODNs.

Main Results:

• Several PO-ODN sequences complementary to the HIV-1 vpr gene (PO-ODNs-a-vpr) potently inhibited HIV-1 multiplication (0.8-3.3 microM) without cytotoxicity up to 100 microM.
• PO-ODN-a-vpr sequences did not inhibit HIV-2, HIV-1 reverse transcriptase, or cell fusion.
• Inhibition occurred post-adsorption but prior to reverse transcription.
• Antiviral activity was linked to contiguous guanine residues, forming G-quartet stabilized tetramers, not an antisense mechanism.

Conclusions:

• Unmodified PO-ODNs targeting the HIV-1 vpr gene can be potent and non-toxic inhibitors of viral replication.
• The antiviral mechanism involves G-quartet formation, disrupting an early stage of HIV-1 replication.
• These findings highlight a novel therapeutic strategy for HIV-1 using G-rich ODNs.