HIV-1 Resistance to Maraviroc Conferred by a CD4 Binding Site Mutation in the Envelope Glycoprotein gp120

Abstract

Maraviroc (MVC) is a CCR5 antagonist that inhibits HIV-1 entry by binding to the coreceptor and inducing structural alterations in the extracellular loops. In this study, we isolated MVC-resistant variants from an HIV-1 primary isolate that arose after 21 weeks of tissue culture passage in the presence of inhibitor. gp120 sequences from passage control and MVC-resistant cultures were cloned into NL4-3 via yeast-based recombination followed by sequencing and drug susceptibility testing. Using 140 clones, three mutations were linked to MVC resistance, but none appeared in the V3 loop as was the case with previous HIV-1 strains resistant to CCR5 antagonists. Rather, resistance was dependent upon a single mutation in the C4 region of gp120. Chimeric clones bearing this N425K mutation replicated at high MVC concentrations and displayed significant shifts in 50% inhibitory concentrations (IC 50 s), characteristic of resistance to all other antiretroviral drugs but not typical of MVC resistance. Previous reports on MVC resistance describe an ability to use a drug-bound form of the receptor, leading to reduction in maximal drug inhibition. In contrast, our structural models on K425 gp120 suggest that this resistant mutation impacts CD4 interactions and highlights a novel pathway for MVC resistance.

Multifaceted Mechanisms of HIV Inhibition and Resistance to CCR5 Inhibitors PSC-RANTES and Maraviroc

“…However, increasing virus concentration reduced MVC inhibition, suggesting a competition between virus and MVC for CCR5 binding. The potential for competitive MVC and PSC-RANTES inhibition is consistent with the resistance mechanisms observed with different MVC-resistant and PSC-RANTES-resistant viruses (19,20). Overall, we provide here a detailed characterization of inhibition and resistance to the U.S. Food and Drug Administration-approved CCR5 antagonist, MVC, and the CCR5 agonist, PSC-RANTES.…”

“…Both the wild-type and the PSC-RANTES-resistant viruses showed similar sensitivities to drugs not targeting the host cell entry step in replication. Finally, all entry inhibitors and each of these viruses (in the present study) have been tested using human PBMCs in the past and to confirm resistance, as observed in the U87 cells (16,19,20,23,27). The present study is designed to carefully define drug mechanism.…”

“…Resistant HIV-1 isolates are able to enter host cells via a drug-bound form of CCR5 and are capable of replicating at even the highest achievable MVC concentrations (4,23,33,34). We have recently characterized an MVC-resistant virus that displays an increase in IC 50 to MVC and has a minimal MPI phenotype (20), whereas the MPI phenotype has been the primary mechanism of MVC resistance with R5 HIV-1 in vitro (5). The results presented here suggest that aside from the allosteric mechanism of inhibition, MVC and R5 HIV-1 may also compete with CCR5 binding.…”

Two-Year Follow-Up of Macaques Developing Intermittent Control of the Human Immunodeficiency Virus Homolog Simian Immunodeficiency Virus SIVmac251 in the Chronic Phase of Infection

“…For the former, RNA was extracted from plasma samples, and the SIV env gene was then reverse transcribed and PCR amplified from the plasma RNA with the SIV versions of the primers described previously (24). Pyrosequencing of the C2-V3 region was performed on PCR amplicons, i.e., amplified from gp130 env DNA fragments.…”

Impact of the Maraviroc-Resistant Mutation M434I in the C4 Region of HIV-1 gp120 on Sensitivity to Antibody-Mediated Neutralization

“…Although maraviroc (MVC), which is the first and currently only approved CCR5 antagonist for the treatment of CCR5-tropic (R5) HIV-1 infected patients, and another CCR5 inhibitor, vicriviroc (VCV), can efficiently suppress HIV-1 replication, drug-resistant variants can arise both in vitro and in vivo using drug-bound CCR5 for cellular entry (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). The presence of MVC-resistant HIV-1 variants may be due to the outgrowth of pre-existing CXCR4-tropic (X4) HIV-1 viruses (19,20) or the selection of MVC-resistant R5 mutants (12,17).…”