Potent inhibition of HIV-1 entry by (s4dU)35

Abstract

We have previously reported the potent in vitro HIV-1 anti-reverse transcriptase activity of a 35-mer of 4-thio-deoxyuridylate [(s(4)dU)(35)]. In efforts to define its activity in a more physiological system, studies were carried out to determine the stage of viral infection that this compound mediates its anti-viral effect. Results of the studies reported herein show that (s(4)dU)(35) is nontoxic and is capable of inhibiting both single and multi-drug resistant HIV strains (IC(50): 0.8-25.4 microg/ml) in vitro. Besides its previously reported anti-RT activity, (s(4)dU)(35) mediated its antiviral action by preventing virus attachment (IC(50): 0.002-0.003 microg/ml), and was stable in vitro and slowly degraded by DNAses. Competition studies and fluorescence resonance energy transfer (FRET) experiments indicated that (s(4)dU)(35) preferentially binds to CD4 receptors, but not to CD48. Confocal laser scanning microscopy (CLSM) studies showed that (s(4)dU)(35) did not penetrate into the cells and colocalized with cell surface thioredoxin. Our studies identify (s(4)dU)(35) as a potential novel HIV entry inhibitor that may have utility as either a systemic antiretroviral or as a preventing agent for HIV transmission.

4‐Thio‐deoxyuridylate‐modified thrombin aptamer and its inhibitory effect on fibrin clot formation, platelet aggregation and thrombus growth on subendothelial matrix

“…The C15‐mer binds to a discrete region within thrombin exosite 1 (fibrinogen recognition exosite), which overlaps the platelet receptor and thrombomodulin binding sites [8,16,17]. In our earlier studies, 4‐thio‐deoxyuridylate‐containing oligonucleotides showed high‐affinity binding to certain proteins [18,19]. Here, we examined the effects of 4‐thio‐deoxyuridylate‐containing analogs of the thrombin‐binding aptamer on different hemostatic/thrombotic activities of thrombin and compared them with the effect of C15‐mer.…”

Antiretroviral effect of 4-thio-uridylate against human immunodeficiency virus type 1

“…In addition to conformational changes in cell surface receptors, coreceptors of HIV and viral envelope proteins, redox changes in these proteins are also required for successful HIV-1 entry and infection. Several inhibitors of protein disulfide isomerase (PDI) as well as cell-surface-thiol interacting agents including thioredoxin, influence HIV infection [14,15] indicating that redox processes active in viral entry could be potential targets for treatment of HIV infection, as we and others reported earlier [14][15][16][17][18].…”

“…It must be noted that UD29 is a mononucleotide, however, its deoxyoligonucleotide derivatives are also active biologically inhibiting the HIV entry and the telomerase enzyme [18,29,30]. Preliminary results on the activity of some other derivatives of the thiolated nucleotide and polynucleotide have also been reported [31].…”

“…The 4-thio uridylate (designated as UD29) was prepared by H 2 S treatment of cytidine 5'-monophosphate, as described for oligonucleotides [18], and was provided by Dr. Janos Aradi, University of Debrecen. A 20 mM (6.66 mg/ml) aqueous stock solution of UD29 was prepared and kept at -20º C. It was diluted to the required concentration with tissue culture media before use.…”

Dissecting HIV Fusion: Identifying Novel Targets for Entry Inhibitors

“…Time of addition experiments suggest a target consistent with an early lifecycle event, such as fusion, and this was confirmed using cell-cell fusion experiments. Subsequent investigation led to the determination that (s 4 dU) 35 inhibits viral attachment and is a potent fusion inhibitor with IC 50 of 0.002 µg/ml [29]. Studies indicate that (s 4 dU) 35 binds to CD4 and co-localizes with thioredoxin.…”