The goal of this Core is to design, synthesize and evaluate selected chemical modifications to small interfering? RNAs (siRNAs) for improved chemical stability and delivery to cells within the cervicovaginal mucosa that? are important in HIV transmission. Previous experience with in vivo applications of oligonucleotides? (including antigene, antisense, decoy, and ribozyme therapies) has clearly demonstrated the need for? chemical modification to improve pharmacokinetics in mammalian systems. Although there are virtually no? technical limitations regarding chemical modification of the nucleobase, sugar and phosphate moieties of? RNA, interactions of the siRNA with the proteins involved in gene silencing puts constraints on the types of? modifications and the number of residues that can be modified without severely impairing the efficacy of the? siRNA. Optimization of delivery, stability, and activity of siRNAs for vaginal delivery will require an? assessment of a range of chemical modifications for incorporation within and near the termini of siRNAs in? combination with cholesterol or CCR5-ligand conjugation for enhancement of uptake into cells susceptible to? infection. Finally, the selected siRNAs will be appropriately formulated for clinical intravaginal application.? This Core will provide modified and formulated siRNAs to each of the Projects for in vitro and in vivo assays? to test the potential of specific modifications for gene silencing and for protection against viral transmission in? cell lines, primary cells and cervicovaginal explants (Project by Lieberman), in mice (Project by Palliser) and in rhesus macaques? (Project by Veazey). The ultimate commercial product from this study will be a drug that can be used vaginally to? prevent infection by HIV. In particular, our aims are to (1) improve biological stability of siRNA duplexes by? adding phosphorothioate linkages to the backbone and by modification of the 2' position of the sugar? residues; (2) improve cell targeting and permeation by conjugation of cholesterol, CCR5-specific ligands, or? mannose to siRNA; and (3) develop an siRNA formulation suitable for clinical intravaginal application.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Program--Cooperative Agreements (U19)
Project #
5U19AI070302-02
Application #
7486248
Study Section
Special Emphasis Panel (ZRG1)
Project Start
Project End
Budget Start
2007-09-01
Budget End
2008-08-31
Support Year
2
Fiscal Year
2007
Total Cost
$432,177
Indirect Cost
Name
Immune Disease Institute, Inc.
Department
Type
DUNS #
059709394
City
Boston
State
MA
Country
United States
Zip Code
02115
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Wheeler, Lee Adam; Trifonova, Radiana; Vrbanac, Vladimir et al. (2011) Inhibition of HIV transmission in human cervicovaginal explants and humanized mice using CD4 aptamer-siRNA chimeras. J Clin Invest 121:2401-12
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