Novel Dual Inhibitory Function Aptamer–siRNA Delivery System for HIV-1 Therapy

Abstract

The successful use of small interfering RNAs (siRNAs) for therapeutic purposes requires safe and efficient delivery to specific cells and tissues. In this study, we demonstrate cell type-specific delivery of anti-human immunodeficiency virus (anti-HIV) siRNAs through fusion to an anti-gp120 aptamer. The envelope glycoprotein is expressed on the surface of HIV-1-infected cells, allowing binding and internalization of the aptamer-siRNA chimeric molecules. We demonstrate that the anti-gp120 aptamer-siRNA chimera is specifically taken up by cells expressing HIV-1 gp120, and that the appended siRNA is processed by Dicer; this releases an anti-tat/rev siRNA which, in turn, inhibits HIV replication. We show for the first time a dual functioning aptamer-siRNA chimera in which both the aptamer and the siRNA portions have potent anti-HIV activities. We also show that gp120 expressed on the surface of HIV-infected cells can be used for aptamer-mediated delivery of anti-HIV siRNAs.

Protection of HIV Neutralizing Aptamers against Rectal and Vaginal Nucleases

“…Accordingly, we have isolated and characterized a short sequence of 2Ј-F-stabilized RNA that is able to specifically bind to gp120 of HIV-1 and inhibit infection in vitro (22). Moreover, this molecule has been used to target HIV-infected cells with siRNA-based inhibitors (13). Due to the high safety rating of RNA-based molecules (23), this would provide a highly advantageous platform for a pre-exposure microbicide product.…”

“…This aptamer has been used to deliver anti-HIV-targeted siRNA molecules to HIV-infected cells by virtue of its specific gp120 binding properties (13). Additionally, it is being developed as an anti-HIV microbicide candidate.…”

Special delivery: targeted therapy with small RNAs

“…45,46 Similarly, a chimeric RNA containing an aptamer to HIV env protein specifically delivers siRNAs to HIV-infected CD4 + cells, which are otherwise refractory to transfection, and when joined with siRNAs that target viral genes can be used to inhibit HIV replication in vitro. 47,48 An siRNA-aptamer encoding a CD4 aptamer knocks down gene expression specifically in human CD4+ T cells, macrophages and dendritic cells. 49 Intravaginal administration of CD4 aptamer-siRNA chimeras designed to knock down CCR5 and/or viral genes can even prevent sexual transmission of HIV in humanized mice.…”

Smart functional nucleic acid chimeras: Enabling tissue specific RNA targeting therapy

“…41 The dual inhibitory function means that both the aptamer and the siRNA components have potent anti-HIV activities, making this capable of targeting the disease at 2 different levels. In this work, they used an anti-gp120 RNA aptamer, targeting the gp120 glycoprotein, a surface protein on the virion that largely determines the entry of HIV into cells, its cellular tropism as well as elements of its pathogenesis.…”

“…In this work, they used an anti-gp120 RNA aptamer, targeting the gp120 glycoprotein, a surface protein on the virion that largely determines the entry of HIV into cells, its cellular tropism as well as elements of its pathogenesis. [41][42][43][44] The aptamer itself is able to bind this protein and neutralize the strains. 45 The other part of the chimera contains an anti-tat/ rev siRNA that inhibits HIV replication.…”