Combinatorial selection and delivery of thioaptamers

Area of Science:

• Biochemistry
• Molecular Biology
• Antiviral Therapeutics

Background:

• Oligonucleotide-based agents offer an alternative to traditional small-molecule drugs.
• HIV reverse transcriptase (RT) is a key target for antiviral therapies.

Purpose of the Study:

• To isolate and characterize DNA aptamers targeting the RNase H domain of HIV RT.
• To evaluate the antiviral efficacy of these modified aptamers (thioaptamers) against HIV.

Main Methods:

• Combinatorial selection methods were used to identify thioaptamers.
• In vitro studies assessed inhibition of RNase H activity.
• Cell culture experiments evaluated HIV production and replication inhibition.
• Gel electrophoretic mobility-shift assays and NMR spectroscopy confirmed binding specificity.

Main Results:

• A thioaptamer specifically bound to the RNase H domain of HIV RT, not E. coli RNase H.
• The thioaptamer inhibited HIV RT RNase H activity in vitro.
• Transfected thioaptamers reduced HIV production in cell cultures by up to 83% in a dose-dependent manner.
• Liposome-based delivery achieved >70% transfection efficiency in HIV-infected cells.

Conclusions:

• Monothiophosphate-backbone-modified DNA aptamers (thioaptamers) are effective inhibitors of HIV replication.
• Thioaptamers represent a promising new class of oligonucleotide-based therapeutic agents for HIV.
• Specific targeting of HIV RT RNase H by thioaptamers offers a viable antiviral strategy.