Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human immunodeficiency virus (HIV), the retrovirus believed to be the cause of acquired immunodeficiency syndrome (AIDS), infects a variety of CD4+ cells, including lymphocytes and cells of the monocyte/macrophage lineage. Encoded in the HIV genome are several precursor proteins that must undergo proteolytic cleavage to yield functional proteins. The gag precursor protein of HIV (p55) is cleaved by a virally encoded aspartate protease (HIV protease). Because cleavage of p55 is required for viral maturation and infectivity, inhibition of HIV protease is an attractive target for therapy designed to block the progression of HIV infection. Inhibitors of HIV protease from a variety of chemical classes have been synthesized and antiviral activity has been demonstrated in lymphocytes and cells from the monocyte/macrophage lineage. A few HIV protease inhibitors have progressed to the clinic and some have shown promise in early trials. There are, however, several important issues that will affect the development of a successful HIV protease inhibitor, including cell and tissue distribution and immunotoxicity. These issues are tissue distribution and immunotoxicity. These issues are discussed, with an emphasis on the complexities posed by cells of the monocyte/macrophage lineage.
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PMID:HIV protease inhibitors: effects on viral maturation and physiologic function in macrophages. 808 11

Inhibitors of the human immunodeficiency virus type 1 (HIV-1) protease represent a promising addition to the available agents used to inhibit virus replication in a therapeutic setting. HIV-1 is capable of generating phenotypic variants in the face of a variety of selective pressures. The potential to generate variants with reduced sensitivity to a protease inhibitor was examined by selecting for virus growth in cell culture in the presence of the protease inhibitor A-77003. Virus variants grew out in the presence of the inhibitor, and these variants encoded proteases with reduced sensitivity to the inhibitor. Variants were identified that encoded changes in each of the three subsites of the protease that interact with the inhibitor. HIV-1 displays significant potential for altering its interaction with this protease inhibitor, suggesting the need for multiple protease inhibitors with varying specificities.
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PMID:Selection of multiple human immunodeficiency virus type 1 variants that encode viral proteases with decreased sensitivity to an inhibitor of the viral protease. 820 33

A synthetic peptide, RPI 312, that specifically inhibits the protease of the human immunodeficiency virus type 1 (HIV-1) showed a potent inhibition on virus production, maturation, and infectivity. Treatment with this agent prevented the cleavage of Gag protein at the site between p17 and p24 in HIV-1 chronically infected MOLT-4 cells as well as in the released virus. Passage of HIV-1 in the presence of gradually increasing concentrations of this protease inhibitor resulted in emergence of a variant that could evade the drug effects. In the resistant variant the maturation of Gag proteins appeared normal, but its infectivity was reduced compared with that of the parent virus. The nucleotides coding the amino acids at and around the cleavage site between Gag proteins p17 and p24 were not changed. One point mutation (A-->G) at site 2082 of the pol gene that resulted in one amino acid change at site 84 of the protease from isoleucine to valine (I-84-->V) could be detected in the resistant variant. An HIV-1 infectious DNA clone with the I-84-->V mutation also showed reduced sensitivity to this protease inhibitor. The findings that the resistant variant had lower infectivity and was still affected by higher doses of the drug support the speculation that resistance to protease inhibitors may not be as problematic as other drug resistance.
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PMID:Generation and characterization of a human immunodeficiency virus type 1 (HIV-1) mutant resistant to an HIV-1 protease inhibitor. 825 33

We present the application of free energy perturbation theory/molecular dynamics to predict the consequence of replacing each of the seven peptide bonds in the potent HIV protease inhibitor JG365: ACE (acetyl)-Ser-Leu-Asn-HEA (hydroxyethylamine analog of Phe-Pro)-Ile-Val-NME (N-methyl) by ethylene or fluoroethylene isosteres. Replacing two of these bonds may well lead to significantly tighter binding; replacing two others is predicted to significantly diminish the binding affinity. Also, for three of the peptide bonds fluoroethylene replacements could lead to increased binding of free energies of the inhibitors. Our results should be considered as predictive since there are, as yet, no experimental results on such peptide replacements as enzyme inhibitors.
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PMID:Peptide mimetics as enzyme inhibitors: use of free energy perturbation calculations to evaluate isosteric replacement for amide bonds in a potent HIV protease inhibitor. 837 26

A-77003, a human immunodeficiency virus type 1 (HIV-1) protease inhibitor, is effective for both acute and chronic infection in vitro and was evaluated clinically by continuous intravenous infusion administration. The minimum effective dose (the concentration required to completely inhibit viral replication) was determined in vitro in a population of uninfected (99%) and HIV-infected (1%) cells exposed to A-77003 by continuous infusion in hollow-fiber bioreactors. The production of infectious HIV and release of p24 antigen from infected cells were completely inhibited in cultures exposed to A-77003 at or above a concentration of 0.5 microM. Measurement of unintegrated HIV-1 DNA synthesis and flow cytometric analysis for cells expressing HIV p24 antigen demonstrated that the spread of HIV to uninfected cells was also blocked at 0.5 microM A-77003. Dose deescalation to 0.25 microM or removal of A-77003 resulted in the limited spread of the virus throughout the culture, the resumption of viral DNA synthesis, and release of p24. HIV produced after exposure to 0.5 microM A-77003 was noninfectious for a period of 72 h after the removal of the drug. Addition of 1 mg of alpha 1-acid glycoprotein per ml to this in vitro system completely ablated the anti-HIV effect of 0.5 microM A-77003. These data suggest that determination of the minimum effective dose under conditions which simulate human pharmacodynamic patterns may be useful in determining the initial dose and schedule for clinical trials. However, other factors, such as serum protein binding, may influence the selection of a therapeutic regimen.
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PMID:Efficacy of constant infusion of A-77003, an inhibitor of the human immunodeficiency virus type 1 (HIV-1) protease, in limiting acute HIV-1 infection in vitro. 858 38

Systematic modifications of HIV protease inhibitor (2R,3S,4S)-4-[[(benzyloxycarbonyl)-L-valyl]-amino]-3-hydroxy-2-[(4- methoxybenzyl)amino]-5-phenylpentanoyl)-L-valine 2-(aminomethyl)- benzimidazole amide led to a novel series of inhibitors with shortened, modified carboxy terminus. Their synthesis, in vitro enzyme inhibitory data, and antiviral activities are reported. Of particular interest are derivatives featuring the (1S,2R)-1-amino-2-hydroxyindan moiety at the P2'-position since some of them exhibit substantial oral bioavailability in mice. The influence of aqueous solubility and structural parameters on the oral resorption of the inhibitors is discussed. Optimum enhancement of oral bioavailability was observed with L-tert-leucine in P2-position, resulting in the discovery of (2R,3S,4S)-4-[[(benzyloxycarbonyl)-L-tert-leucyl]- amino]-3-hydroxy-2-[(4-methoxybenzyl)amino]-5-phenylpentanoic acid (1S,2R)-1-amino-2-hydroxyindan amide which combines high antiviral activity (IC50 = 250 nM) with a good pharmacokinetic profile (AUC = 82.5 microM.h at a dose of 125 mg/kg po in mice).
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PMID:Inhibitors of human immunodeficiency virus type 1 protease containing 2-aminobenzyl-substituted 4-amino-3-hydroxy-5-phenylpentanoic acid: synthesis, activity, and oral bioavailability. 864 65

The potential contribution of recombination to the development of HIV-1 resistance to multiple drugs was investigated. Two distinct viruses, one highly resistant to a protease inhibitor (SC-52151) and the other highly resistant to zidovudine, were used to coinfect T lymphoblastoid cells in culture. The viral genotypes could be distinguished by four mutations conferring drug resistance to each drug and by other sequence differences specific for each parental virus. Progeny virions recovered from mixed infection were passaged in the presence and absence of both zidovudine and SC-52151. Dually resistant mutants emerged rapidly under selective conditions, and these viruses were genetic recombinants. These results emphasize that genetic recombination could contribute to high-level multiple-drug resistance and that this process must be considered in chemotherapeutic strategies for HIV infection.
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PMID:Recombination leads to the rapid emergence of HIV-1 dually resistant mutants under selective drug pressure. 865 Feb 27

Analysis of the HIV protease gene from the plasma of HIV-infected patients revealed substitutions at nine different codons selected in response to monotherapy with the protease inhibitor ritonavir. Mutants at valine-82, although insufficient to confer resistance, appeared first in most patients. Significant phenotypic resistance required multiple mutations in HIV protease, which emerged subsequently in an ordered, stepwise fashion. The appearance of resistance mutations was delayed in patients with higher plasma levels of ritonavir. Early mutants retained susceptibility to structurally diverse protease inhibitors, suggesting that dual protease inhibitor therapy might increase the duration of viral suppression.
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PMID:Ordered accumulation of mutations in HIV protease confers resistance to ritonavir. 867 21

CD4+ T-lymphocyte apoptosis has been associated with human immunodeficiency virus (HIV)-1 infection in vitro, paralleling the expression of Fas (APO-1, CD95) on peripheral blood mononuclear cells from patients with HIV disease. However, the link between Fas induction, T-cell activation, and cell death is unclear. We document, for the first time, marked upregulation of expression of mRNA for the ligand for Fas in peripheral blood mononuclear cells from HIV seropositive individuals, and demonstrate the ability of HIV infection to induce such expression in CD4+ T cells in vitro. We also define the relevance of this expression to HIV-mediated CD4+ T cell death. Our ability to downregulate Fas ligand message and suppress HIV-mediated apoptosis with aurintricarboxylic acid, a clinically used protease inhibitor with known activity against programmed cell death in other systems, may open up a new area of therapy for HIV infection.
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PMID:HIV-1 upregulates Fas ligand expression in CD4+ T cells in vitro and in vivo: association with Fas-mediated apoptosis and modulation by aurintricarboxylic acid. 867 12

As new antiretroviral drugs for the treatment of human immunodeficiency virus (HIV) infection and new tests to measure HIV infection have become available, primary care clinicians now have more management options than ever before. Viral load measurements are becoming more accepted as a means of assessing HIV disease and estimating the efficacy of specific drug regimens. Clinical status changes also mark times to review antiretroviral regimens. Potential benefits of combination drug therapy, including the new protease inhibitor class of drugs, have added a new sense of optimism to the care of patients with HIV. Whether combination therapy and protease inhibitor treatment will live up to their promise by inducing better long-term clinical results remains to be seen.
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PMID:Antiretroviral drug treatment for HIV/AIDS. 870 38


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