scholarly journals Monomeric APOBEC3G Is Catalytically Active and Has Antiviral Activity

2006 ◽  
Vol 80 (10) ◽  
pp. 4673-4682 ◽  
Author(s):  
Sandrine Opi ◽  
Hiroaki Takeuchi ◽  
Sandra Kao ◽  
Mohammad A. Khan ◽  
Eri Miyagi ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Cytidine Deaminase ◽  
Cysteine Residue ◽  
Catalytic Function ◽  
Immunodeficiency Virus ◽  
Catalytically Active ◽  
Antiviral Function ◽  
Rnase Treatment ◽  
Hiv 1

ABSTRACT APOBEC3G (APO3G) is a cytidine deaminase that restricts replication of vif-defective human immunodeficiency virus type 1 (HIV-1). Like other members of the cellular deaminase family, APO3G has the propensity to form homo-multimers. In the current study, we investigated the functional determinants for multimerization of human APO3G and studied the role of APO3G multimerization for catalytic activity, virus encapsidation, and antiviral activity. We found that human APO3G is capable of forming multimeric complexes in transfected HeLa cells. Interestingly, multimerization of APO3G was exquisitely sensitive to RNase treatment, suggesting that interaction of APO3G subunits is facilitated or stabilized by an RNA bridge. Mutation of a conserved cysteine residue (C97) that is part of an N-terminal zinc-finger motif in APO3G abolished multimerization of APO3G; however, the C97 mutation inhibited neither in vitro deaminase activity nor antiviral function of APO3G. These results suggest that monomeric APO3G is both catalytically active and has antiviral activity. Interference studies employing either catalytically inactive or packaging-incompetent APO3G variants suggest that wild-type APO3G is packaged into HIV-1 particles in monomeric form. These results provide novel insights into the catalytic function and antiviral property of APO3G and demonstrate an important role for C97 in the RNA-dependent multimerization of this protein.

scholarly journals 7SL RNA Mediates Virion Packaging of the Antiviral Cytidine Deaminase APOBEC3G

2007 ◽  
Vol 81 (23) ◽  
pp. 13112-13124 ◽  
Author(s):  
Tao Wang ◽  
Chunjuan Tian ◽  
Wenyan Zhang ◽  
Kun Luo ◽  
Phuong Thi Nguyen Sarkis ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Rna Binding ◽  
Cytidine Deaminase ◽  
Rna Packaging ◽  
Cellular Functions ◽  
7Sl Rna ◽  
Immunodeficiency Virus ◽  
Antiviral Function ◽  
Pol Iii ◽  
Hiv 1

ABSTRACT Cytidine deaminase APOBEC3G (A3G) has broad antiviral activity against diverse retroviruses and/or retrotransposons, and its antiviral functions are believed to rely on its encapsidation into virions in an RNA-dependent fashion. However, the cofactors of A3G virion packaging have not yet been identified. We demonstrate here that A3G selectively interacts with certain polymerase III (Pol III)-derived RNAs, including Y3 and 7SL RNAs. Among A3G-binding Pol III-derived RNAs, 7SL RNA was preferentially packaged into human immunodeficiency virus type 1 (HIV-1) particles. Efficient packaging of 7SL RNA, as well as A3G, was mediated by the RNA-binding nucleocapsid domain of HIV-1 Gag. A3G mutants that had reduced 7SL RNA binding but maintained wild-type levels of mRNA and tRNA binding were packaged poorly and had impaired antiviral activity. Reducing 7SL RNA packaging by overexpression of SRP19 proteins inhibited 7SL RNA and A3G virion packaging and impaired its antiviral function. Thus, 7SL RNA that is encapsidated into diverse retroviruses is a key cofactor of the antiviral A3G. This selective interaction of A3G with certain Pol III-derived RNAs raises the question of whether A3G and its cofactors may have as-yet-unidentified cellular functions.

scholarly journals In Vitro Antiviral Activity and Cross-Resistance Profile of PL-100, a Novel Protease Inhibitor of Human Immunodeficiency Virus Type 1

2007 ◽  
Vol 51 (11) ◽  
pp. 4036-4043 ◽  
Author(s):  
Serge Dandache ◽  
Guy Sévigny ◽  
Jocelyn Yelle ◽  
Brent R. Stranix ◽  
Neil Parkin ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiviral Activity ◽  
Highly Active Antiretroviral Therapy ◽  
Cross Resistance ◽  
Drug Resistant ◽  
Resistance Profile ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Despite the success of highly active antiretroviral therapy, the current emergence and spread of drug-resistant variants of human immunodeficiency virus (HIV) stress the need for new inhibitors with distinct properties. We designed, produced, and screened a library of compounds based on an original l-lysine scaffold for their potentials as HIV type 1 (HIV-1) protease inhibitors (PI). One candidate compound, PL-100, emerged as a specific and noncytotoxic PI that exhibited potent inhibition of HIV-1 protease and viral replication in vitro (Ki , ∼36 pM, and 50% effective concentration [EC50], ∼16 nM, respectively). To confirm that PL-100 possessed a favorable resistance profile, we performed a cross-resistance study using a panel of 63 viral strains from PI-experienced patients selected for the presence of primary PI mutations known to confer resistance to multiple PIs now in clinical use. The results showed that PL-100 retained excellent antiviral activity against almost all of these PI-resistant viruses and that its performance in this regard was superior to those of atazanavir, amprenavir, indinavir, lopinavir, nelfinavir, and saquinavir. In almost every case, the increase in the EC50 for PL-100 observed with viruses containing multiple mutations in protease was far less than that obtained with the other drugs tested. These data underscore the potential for PL-100 to be used in the treatment of drug-resistant HIV disease and argue for its further development.

scholarly journals In Vitro Antiviral Activity of the Novel, Tyrosyl-Based Human Immunodeficiency Virus (HIV) Type 1 Protease Inhibitor Brecanavir (GW640385) in Combination with Other Antiretrovirals and against a Panel of Protease Inhibitor-Resistant HIV

2007 ◽  
Vol 51 (9) ◽  
pp. 3147-3154 ◽  
Author(s):  
Richard Hazen ◽  
Robert Harvey ◽  
Robert Ferris ◽  
Charles Craig ◽  
Phillip Yates ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiviral Activity ◽  
Protease Inhibitor ◽  
Reverse Transcriptase ◽  
In Vitro Assays ◽  
Immunodeficiency Virus ◽  
Anti Hiv ◽  
Hiv 1

ABSTRACT Brecanavir, a novel tyrosyl-based arylsulfonamide, high-affinity, human immunodeficiency virus type 1 (HIV-1) protease inhibitor (PI), has been evaluated for anti-HIV activity in several in vitro assays. Preclinical assessment of brecanavir indicated that this compound potently inhibited HIV-1 in cell culture assays with 50% effective concentrations (EC50s) of 0.2 to 0.53 nM and was equally active against HIV strains utilizing either the CXCR4 or CCR5 coreceptor, as was found with other PIs. The presence of up to 40% human serum decreased the anti-HIV-1 activity of brecanavir by 5.2-fold, but under these conditions the compound retained single-digit nanomolar EC50s. When brecanavir was tested in combination with nucleoside reverse transcriptase inhibitors, the antiviral activity of brecanavir was synergistic with the effects of stavudine and additive to the effects of zidovudine, tenofovir, dideoxycytidine, didanosine, adefovir, abacavir, lamivudine, and emtricitabine. Brecanavir was synergistic with the nonnucleoside reverse transcriptase inhibitor nevirapine or delavirdine and was additive to the effects of efavirenz. In combination with other PIs, brecanavir was additive to the activities of indinavir, lopinavir, nelfinavir, ritonavir, amprenavir, saquinavir, and atazanavir. Clinical HIV isolates from PI-experienced patients were evaluated for sensitivity to brecanavir and other PIs in a recombinant virus assay. Brecanavir had a <5-fold increase in EC50s against 80% of patient isolates tested and had a greater mean in vitro potency than amprenavir, indinavir, lopinavir, atazanavir, tipranavir, and darunavir. Brecanavir is by a substantial margin the most potent and broadly active antiviral agent among the PIs tested in vitro.

scholarly journals Enzymatically Active APOBEC3G Is Required for Efficient Inhibition of Human Immunodeficiency Virus Type 1

2007 ◽  
Vol 81 (24) ◽  
pp. 13346-13353 ◽  
Author(s):  
Eri Miyagi ◽  
Sandrine Opi ◽  
Hiroaki Takeuchi ◽  
Mohammad Khan ◽  
Ritu Goila-Gaur ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiviral Activity ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Viral Genome ◽  
Cytidine Deaminase ◽  
Immunodeficiency Virus ◽  
Catalytically Active ◽  
Antiviral Activities

ABSTRACT APOBEC3G (APO3G) is a cellular cytidine deaminase with potent antiviral activity. Initial studies of the function of APO3G demonstrated extensive mutation of the viral genome, suggesting a model in which APO3G's antiviral activity is due to hypermutation of the viral genome. Recent studies, however, found that deaminase-defective APO3G mutants transiently expressed in virus-producing cells exhibited significant antiviral activity, suggesting that the antiviral activity of APO3G could be dissociated from its deaminase activity. To directly compare the antiviral activities of wild-type (wt) and deaminase-defective APO3G, we used two approaches: (i) we titrated wt and deaminase-defective APO3G in transient-transfection studies to achieve similar levels of virus-associated APO3G and (ii) we constructed stable cell lines and selected clones expressing comparable amounts of wt and deaminase-defective APO3G. Viruses produced under these conditions were tested for viral infectivity. The results from the two approaches were consistent and suggested that the antiviral activity of deaminase-defective APO3G was significantly lower than that of wt APO3G. We conclude that efficient inhibition of vif-defective human immunodeficiency virus type 1 requires catalytically active APO3G.

scholarly journals Circulating Metabolites of the Human Immunodeficiency Virus Protease Inhibitor Nelfinavir in Humans: Structural Identification, Levels in Plasma, and Antiviral Activities

2001 ◽  
Vol 45 (4) ◽  
pp. 1086-1093 ◽  
Author(s):  
Kanyin E. Zhang ◽  
Ellen Wu ◽  
Amy K. Patick ◽  
Bradley Kerr ◽  
Mark Zorbas ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiviral Activity ◽  
Protease Inhibitor ◽  
Active Metabolite ◽  
Parent Drug ◽  
Hiv Reverse Transcriptase ◽  
Immunodeficiency Virus ◽  
Antiviral Activities ◽  
Hiv 1

ABSTRACT Nelfinavir mesylate (Viracept, formally AG1343) is a potent and orally bioavailable human immunodeficiency virus (HIV) type 1 (HIV-1) protease inhibitor (K i = 2 nM) and is being widely prescribed in combination with HIV reverse transcriptase inhibitors for the treatment of HIV infection. The current studies evaluated the presence of metabolites circulating in plasma following the oral administration of nelfinavir to healthy volunteers and HIV-infected patients, as well as the levels in plasma and antiviral activities of these metabolites. The results showed that the parent drug was the major circulating chemical species, followed in decreasing abundance by its hydroxy-t-butylamide metabolite (M8) and 3′-methoxy-4′-hydroxynelfinavir (M1). Antiviral assays with HIV-1 strain RF-infected CEM-SS cells showed that the 50% effective concentrations (EC50) of nelfinavir, M8, and M1 were 30, 34, and 151 nM, respectively, and that the corresponding EC50 against another HIV-1 strain, IIIB, in MT-2 cells were 60, 86, and 653 nM. Therefore, apparently similar in vitro antiviral activities were demonstrated for nelfinavir and M8, whereas an approximately 5- to 11-fold-lower level of antiviral activity was observed for M1. The active metabolite, M8, showed a degree of binding to human plasma proteins similar to that of nelfinavir (ca. 98%). Concentrations in plasma of nelfinavir and its metabolites in 10 HIV-positive patients receiving nelfinavir therapy (750 mg three times per day) were determined by a liquid chromatography tandem mass spectrometry assay. At steady state (day 28), the mean plasma nelfinavir concentrations ranged from 1.73 to 4.96 μM and the M8 concentrations ranged from 0.55 to 1.96 μM, whereas the M1 concentrations were low and ranged from 0.09 to 0.19 μM. In conclusion, the findings from the current studies suggest that, in humans, nelfinavir forms an active metabolite circulating at appreciable levels in plasma. The active metabolite M8 may account for some of the antiviral activity associated with nelfinavir in the treatment of HIV disease.

scholarly journals A Lipopeptide HIV-1/2 Fusion Inhibitor with Highly Potent In Vitro, Ex Vivo, and In Vivo Antiviral Activity

2017 ◽  
Vol 91 (11) ◽  
Author(s):  
Huihui Chong ◽  
Jing Xue ◽  
Shengwen Xiong ◽  
Zhe Cong ◽  
Xiaohui Ding ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Viral Entry ◽  
Ex Vivo ◽  
Rhesus Macaques ◽  
Fusion Inhibitor ◽  
Clinical Use ◽  
Viral Fusion ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Peptides derived from the C-terminal heptad repeat (CHR) region of the human immunodeficiency virus type 1 (HIV-1) fusogenic protein gp41 are potent viral entry inhibitors, and currently, enfuvirtide (T-20) is the only one approved for clinical use; however, emerging drug resistance largely limits its efficacy. In this study, we generated a novel lipopeptide inhibitor, named LP-19, by integrating multiple design strategies, including an N-terminal M-T hook structure, an HIV-2 sequence, intrahelical salt bridges, and a membrane-anchoring lipid tail. LP-19 showed stable binding affinity and highly potent, broad, and long-lasting antiviral activity. In in vitro studies, LP-19 efficiently inhibited HIV-1-, HIV-2-, and simian immunodeficiency virus (SIV)-mediated cell fusion, viral entry, and infection, and it was highly active against diverse subtypes of primary HIV-1 isolates and inhibitor-resistant mutants. Ex vivo studies demonstrated that LP-19 exhibited dramatically increased anti-HIV activity and an extended half-life in rhesus macaques. In short-term monotherapy, LP-19 reduced viral loads to undetectable levels in acutely and chronically simian-human immunodeficiency virus (SHIV)-infected monkeys. Therefore, this study offers an ideal HIV-1/2 fusion inhibitor for clinical development and emphasizes the importance of the viral fusion step as a drug target. IMPORTANCE The peptide drug T-20 is the only viral fusion inhibitor in the clinic, which is used for combination therapy of HIV-1 infection; however, it requires a high dosage and easily induces drug resistance, calling for a new drug with significantly improved pharmaceutical profiles. Here, we have developed a short-lipopeptide-based fusion inhibitor, termed LP-19, which mainly targets the conserved gp41 pocket site and shows highly potent inhibitory activity against HIV-1, HIV-2, and even SIV isolates. LP-19 exhibits dramatically increased antiviral activity and an extended half-life in rhesus macaques, and it has potent therapeutic efficacy in SHIV-infected monkeys, highlighting its high potential as a new viral fusion inhibitor for clinical use.

scholarly journals Antiviral activity of the dihydropyrone PNU-140690, a new nonpeptidic human immunodeficiency virus protease inhibitor.

1997 ◽  
Vol 41 (5) ◽  
pp. 1058-1063 ◽  
Author(s):  
S M Poppe ◽  
D E Slade ◽  
K T Chong ◽  
R R Hinshaw ◽  
P J Pagano ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiviral Activity ◽  
Protease Inhibitors ◽  
Hiv Protease ◽  
Pharmacokinetic Studies ◽  
Hiv Protease Inhibitors ◽  
Highly Active ◽  
Immunodeficiency Virus ◽  
Hiv 1

PNU-140690 is a member of a new class of nonpeptidic human immunodeficiency virus (HIV) protease inhibitors (sulfonamide-containing 5,6-dihydro-4-hydroxy-2-pyrones) discovered by structure-based design. PNU-140690 has excellent potency against a variety of HIV type 1 (HIV-1) laboratory strains and clinical isolates, including those resistant to the reverse transcriptase inhibitors zidovudine or delavirdine. When combined with either zidovudine or delavirdine, PNU-140690 contributes to synergistic antiviral activity. PNU-140690 is also highly active against HIV-1 variants resistant to peptidomimetic protease inhibitors, underscoring the structural distinctions between PNU-140690 and substrate analog protease inhibitors. PNU-140690 retains good antiviral activity in vitro in the presence of human plasma proteins, and preclinical pharmacokinetic studies revealed good oral bioavailability. Accordingly, PNU-140690 is a candidate for clinical evaluation.

scholarly journals Identification and Characterization of UK-201844, a Novel Inhibitor That Interferes with Human Immunodeficiency Virus Type 1 gp160 Processing

2007 ◽  
Vol 51 (10) ◽  
pp. 3554-3561 ◽  
Author(s):  
Wade S. Blair ◽  
Joan Cao ◽  
Lynn Jackson ◽  
Judith Jimenez ◽  
Qinghai Peng ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiviral Activity ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Laboratory Strain ◽  
Immunodeficiency Virus ◽  
Vesicular Stomatitis ◽  
Hiv 1

ABSTRACT More than 106 compounds were evaluated in a human immunodeficiency virus type 1 (HIV-1) high-throughput antiviral screen, resulting in the identification of a novel HIV-1 inhibitor (UK-201844). UK-201844 exhibited antiviral activity against HIV-1 NL4-3 in MT-2 and PM1 cells, with 50% effective concentrations of 1.3 and 2.7 μM, respectively, but did not exhibit measurable antiviral activity against the closely related HIV-1 IIIB laboratory strain. UK-201844 specifically inhibited the production of infectious virions packaged with an HIV-1 envelope (Env), but not HIV virions packaged with a heterologous Env (i.e., the vesicular stomatitis virus glycoprotein), suggesting that the compound targets HIV-1 Env late in infection. Subsequent antiviral assays using HIV-1 NL4-3/IIIB chimeric viruses showed that HIV-1 Env sequences were critical determinants of UK-201844 susceptibility. Consistent with this, in vitro resistant-virus studies revealed that amino acid substitutions in HIV-1 Env are sufficient to confer resistance to UK-201844. Western analysis of HIV Env proteins expressed in transfected cells or in isolated virions showed that UK-201844 inhibited HIV-1 gp160 processing, resulting in the production of virions with nonfunctional Env glycoproteins. Our results demonstrate that UK-201844 represents the prototype for a unique HIV-1 inhibitor class that directly or indirectly interferes with HIV-1 gp160 processing.

scholarly journals Limonoids Containing a C1–O–C29 Moiety: Isolation, Structural Modification, and Antiviral Activity

Marine Drugs ◽  
2018 ◽  
Vol 16 (11) ◽  
pp. 434 ◽  
Author(s):  
Jing-Ling Ren ◽  
Xiao-Peng Zou ◽  
Wan-Shan Li ◽  
Li Shen ◽  
Jun Wu
Keyword(s):  
Antiviral Activity ◽  
Inhibitory Activity ◽  
Influenza A ◽  
Structural Modification ◽  
X Ray Diffraction ◽  
Ic50 Value ◽  
Immunodeficiency Virus ◽  
Antiviral Activities ◽  
Hiv 1

Five new limonoids named thaigranatins A–E (1–5), containing a C1–O–C29 moiety, were isolated from seeds of the Thai Xylocarpus granatum, collected at the mangrove swamp of Trang Province, together with the known limonoid, granatumin L (6). The structures of these compounds were established by HR-ESIMS and extensive NMR spectroscopic data. The absolute configuration of 1 was unequivocally determined by single-crystal X-ray diffraction analysis, conducted with Cu Kα radiation; whereas that of 2 or 6 was established to be the same as that of 1 by the similarity of their electronic circular dichroism (ECD) spectra. In view of the marked antiviral activity of 6, its structure was modified via hydrolysis with alkaline KOH, esterification with diazomethane and various organic acids, and oximization with hydroxyamine. Finally, 18 derivatives, viz. 7–10, 8a–8i, 9a–9b, and 10a–10c, were obtained. In vitro antiviral activities of these derivatives against human immunodeficiency virus 1 (HIV-1) and influenza A virus (IAV) were evaluated. Most notably, 8i exhibited marked inhibitory activity against HIV-1 with an IC50 value of 15.98 ± 6.87 μM and a CC50 value greater than 100.0 μM; whereas 10b showed significant inhibitory activity against IAV with an IC50 value of 14.02 ± 3.54 μM and a CC50 value greater than 100.0 μM.

Antiviral Activity of DG-35-VIII, a Potent Inhibitor of the Protease of Human Immunodeficiency Virus

1997 ◽  
Vol 8 (2) ◽  
pp. 99-106 ◽  
Author(s):  
D Grobelny ◽  
Q Chen ◽  
D Tyssen ◽  
G Tachedjian ◽  
K Sebire ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiviral Activity ◽  
T Lymphocyte ◽  
Potent Inhibitor ◽  
Important Target ◽  
Antiretroviral Drug ◽  
Immunodeficiency Virus ◽  
Precursor Proteins ◽  
Hiv 1

The protease of human immunodeficiency virus (HIV) is an important target for antiretroviral drug therapy. The synthesis and in vitro antiviral activity of a novel protease inhibitor, DG-35-VIII, which contains an hydroxyethylhydrazide core unit, is described. DG-35-VIII had potent activity against HIV-1 and related viruses (HIV-2 and simian immunodeficiency virus) in an acutely infected T lymphocyte line (MT-2) and was also active in cells chronically infected with HIV-1, where it inhibited processing of the Pr55gag and Pr160 gag-pal precursor proteins.

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