title: Potent suppression of HIV type 1 infection by a short hairpin anti-CXCR4 siRNA.
abstract: The phenomenon of RNA interference (RNAi) sparked a new surge in the area of posttranscriptional gene silencing methodologies and their potential application for HIV-1 gene therapy. A potentially promising strategy is to exploit siRNAs to prevent viral entry at the cell surface by down-regulating essential cell surface HIV-1 coreceptors. In the present studies we targeted the CXCR4 coreceptor for disruption with siRNA to inhibit HIV-1 entry as a first step toward the ultimate goal of translating this to gene therapy for AIDS. A stem-loop hairpin structured anti-CXCR4 siRNA was designed and synthesized in vitro by transcription with T7 polymerase. Down-regulation of the coreceptor was assayed in U373-Magi-CXCR4 cells. FACS analysis showed marked down-regulation of CXCR4 on the cell surface and Western blot analysis confirmed the reduced levels of intracellular synthesis. When challenged with X4-tropic HIV-1 NL4-3, the siRNA-transfected cells exhibited marked viral resistance. Consistent with these results, siRNA-transfected primary lymphocytes also exhibited significant resistance to HIV-1 entry. These proof-of-concept studies demonstrated the efficacy of an siRNA targeted to an essential cellular coreceptor CXCR4 in protecting from HIV-1 infection. Delivery of this siRNA into hematopoietic stem cells via lentiviral vectors may have potential gene therapeutic applications.
mesh_terms: D015153:Blotting, Western; D002478:Cells, Cultured; D005434:Flow Cytometry; D020868:Gene Silencing / Q000187:drug effects / Q000502:physiology; D015316:Genetic Therapy; D015658:HIV Infections / Q000517:prevention & control; D015497:HIV-1 / Q000187:drug effects*; D006801:Humans; D034741:RNA, Small Interfering / Q000235:genetics / Q000494:pharmacology*; D019718:Receptors, CXCR4 / Q000037:antagonists & inhibitors*
chemical_list: D034741:RNA, Small Interfering; D019718:Receptors, CXCR4