Article

Impact of Y143 HIV-1 integrase mutations on resistance to raltegravir in vitro and in vivo

LBPA, CNRS UMR8113, Ecole Normale Supérieure de Cachan, 61 Avenue du Président Wilson, 94235 Cachan, France.
Antimicrobial Agents and Chemotherapy (Impact Factor: 4.45). 11/2009; 54(1):491-501. DOI: 10.1128/AAC.01075-09
Source: PubMed

ABSTRACT Integrase (IN), the HIV-1 enzyme responsible for the integration of the viral genome into the chromosomes of infected cells, is the target of the recently approved antiviral raltegravir (RAL). Despite this drug's activity against viruses resistant to other antiretrovirals, failures of raltegravir therapy were observed, in association with the emergence of resistance due to mutations in the integrase coding region. Two pathways involving primary mutations on residues N155 and Q148 have been characterized. It was suggested that mutations at residue Y143 might constitute a third primary pathway for resistance. The aims of this study were to investigate the susceptibility of HIV-1 Y143R/C mutants to raltegravir and to determine the effects of these mutations on the IN-mediated reactions. Our observations demonstrate that Y143R/C mutants are strongly impaired for both of these activities in vitro. However, Y143R/C activity can be kinetically restored, thereby reproducing the effect of the secondary G140S mutation that rescues the defect associated with the Q148R/H mutants. A molecular modeling study confirmed that Y143R/C mutations play a role similar to that determined for Q148R/H mutations. In the viral replicative context, this defect leads to a partial block of integration responsible for a weak replicative capacity. Nevertheless, the Y143 mutant presented a high level of resistance to raltegravir. Furthermore, the 50% effective concentration (EC(50)) determined for Y143R/C mutants was significantly higher than that obtained with G140S/Q148R mutants. Altogether our results not only show that the mutation at position Y143 is one of the mechanisms conferring resistance to RAL but also explain the delayed emergence of this mutation.

Download full-text

Full-text

Available from: Frédéric Subra, Aug 14, 2015
0 Followers
 · 
119 Views
  • Source
    • "T97A is a polymorphic substitution, selected by raltegravir and is related to Y143R/C (Canducci et al., 2009). Although not directly associated to resistance, this mutation is synergic to Y143 resistant mutants, as it is capable of restoring the replication capacity of the virus (fitness), and it is expected to emerge after the fixation of 143R (Delelis et al., 2010; Reigadas et al., 2011). The viral load documented during the presence of F121Y and T97A is over half log below historical values. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Raltegravir is an integrase inhibitor (INI) licensed for clinical use and other INI are in advanced stage of development. Different resistance mutations in HIV integrase from patients using these antiretroviral drugs have been described and G148H/R/K, N155H and less frequently Y143C/H/R are considered major resistant mutations to raltegravir. Both Stanford Database and Geno2Pheno list F121Y as conferring intermediate resistance "in vitro" both to raltegravir and elvitegravir. We report for the first time the "in vivo" selection F121Y and evolution to Y143R in a 31years old male clade B HIV-1 infected patient failing a raltegravir-containing salvage regimen. Plasma samples nine months prior to raltegravir (RAL-Naïve) and at weeks 32, 40 and 88 after RAL-containing regimen were analyzed. Antiretroviral susceptibility was evaluated at Stanford and Geno2Pheno from sequences obtained with RT-PCR. After a Viral load at week 12 below 50 copies/mL, viremia raised at week 20 to 4.5log10. The emergence of F121Y was observed at week 32 and 40, alongside with L74I, T97A, Q137H and V151I. At week 88 F121Y was no longer detected, L74I and T97A were maintained and Y143R emerged. F121Y might be an alternative pathway to Y143R. Changing of RAL-containing regimen upon the identification of F121Y might avoid the evolution of raltegravir resistance.
    Antiviral research 05/2012; 95(1):9-11. DOI:10.1016/j.antiviral.2012.04.007 · 3.94 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper investigates the effects of different voltage magnitude unbalances with the same voltage unbalance factor (VUF) on the stator loss and rotor copper loss and total copper loss of three classes of three-phase induction motor. Under six different voltage magnitudes unbalance conditions, the copper losses of three different three-phase induction motor under full load conditions has been analyzed through simulation. Following the investigations, the importance of the positive-sequence voltage and the negative-sequence voltage has been pointed out. In the present work, the relative percentage increase in the stator copper loss, rotor copper loss and total copper losses have been computed for the motor working under unbalanced and balanced voltages. For this analysis Matlab environment using Simulink toolbox has been used. In this paper the three definitions (line voltage unbalance in percent-LVUR, phase voltage unbalance in percent-PVUR and voltage unbalance factor-VUF) of voltage magnitude unbalance have been considered. The operation of the induction motor has been considered at full load. The analysis shows the effects of resulting losses during unbalanced voltage supply. The increase in losses under unbalanced voltages leads to the necessity of derating the motor.
    Electrical Insulation, 2004. Conference Record of the 2004 IEEE International Symposium on; 10/2004
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: HIV-1 integrase catalyzes the insertion of the viral genome into chromosomal DNA. We characterized the structural determinants of the 3'-processing reaction specificity--the first reaction of the integration process--at the DNA-binding level. We found that the integrase N-terminal domain, containing a pseudo zinc-finger motif, plays a key role, at least indirectly, in the formation of specific integrase-DNA contacts. This motif mediates a cooperative DNA binding of integrase that occurs only with the cognate/viral DNA sequence and the physiologically relevant Mg(2+) cofactor. The DNA-binding was essentially non-cooperative with Mn(2+) or using non-specific/random sequences, regardless of the metallic cofactor. 2,2'-Dithiobisbenzamide-1 induced zinc ejection from integrase by covalently targeting the zinc-finger motif, and significantly decreased the Hill coefficient of the Mg(2+)-mediated integrase-DNA interaction, without affecting the overall affinity. Concomitantly, 2,2'-dithiobisbenzamide-1 severely impaired 3'-processing (IC(50) = 11-15 nM), suggesting that zinc ejection primarily perturbs the nature of the active integrase oligomer. A less specific and weaker catalytic effect of 2,2'-dithiobisbenzamide-1 is mediated by Cys 56 in the catalytic core and, notably, accounts for the weaker inhibition of the non-cooperative Mn(2+)-dependent 3'-processing. Our data show that the cooperative DNA-binding mode is strongly related to the sequence-specific DNA-binding, and depends on the simultaneous presence of the Mg(2+) cofactor and the zinc effector.
    Nucleic Acids Research 02/2010; 38(11):3692-708. DOI:10.1093/nar/gkq087 · 9.11 Impact Factor
Show more