RESUMO
BACKGROUND: Maturation inhibitors (MIs) potently block HIV-1 maturation by inhibiting the cleavage of the capsid protein and spacer peptide 1 (CA-SP1). Bevirimat (BVM), a highly efficacious first-in-class MI against HIV-1 subtype B isolates, elicited sub-optimal efficacy in clinical trials due to polymorphisms in the CA-SP1 region of the Gag protein (SP1:V7A). HIV-1 subtype C inherently contains this polymorphism thus conferring BVM resistance, however it displayed sensitivity to second generation BVM analogs. RESULTS: In this study, we have assessed the efficacy of three novel second-generation MIs (BVM analogs: CV-8611, CV-8612, CV-8613) against HIV-1 subtype B and C isolates. The BVM analogs were potent inhibitors of both HIV-1 subtype B (NL4-3) and subtype C (K3016) viruses. Serial passaging of the subtype C, K3016 virus strain in the presence of BVM analogs led to identification of two mutant viruses-Gag SP1:A1V and CA:I201V. While the SP1:A1V mutant was resistant to the MIs, the CA:I120V mutant displayed partial resistance and a MI-dependent phenotype. Further analysis of the activity of the BVM analogs against two additional HIV-1 subtype C strains, IndieC1 and ZM247 revealed that they had reduced sensitivity as compared to K3016. Sequence analysis of the three viruses identified two polymorphisms at SP1 residues 9 and 10 (K3016: N9, G10; IndieC1/ZM247: S9, T10). The N9S and S9N mutants had no change in MI-sensitivity. On the other hand, replacing glycine at residue 10 with threonine in K3016 reduced its MI sensitivity whereas introducing glycine at SP1 10 in place of threonine in IndieC1 and ZM247 significantly enhanced their MI sensitivity. Thus, the specific glycine residue 10 of SP1 in the HIV-1 subtype C viruses determined sensitivity towards BVM analogs. CONCLUSIONS: We have identified an association of a specific glycine at position 10 of Gag-SP1 with an MI susceptible phenotype of HIV-1 subtype C viruses. Our findings have highlighted that HIV-1 subtype C viruses, which were inherently resistant to BVM, may also be similarly predisposed to exhibit a significant degree of resistance to second-generation BVM analogs. Our work has strongly suggested that genetic differences between HIV-1 subtypes may produce variable MI sensitivity that needs to be considered in the development of novel, potent, broadly-active MIs.
Assuntos
Fármacos Anti-HIV/farmacologia , Regulação Viral da Expressão Gênica/genética , HIV-1/efeitos dos fármacos , HIV-1/genética , Polimorfismo Genético/efeitos dos fármacos , Fator de Transcrição Sp1/antagonistas & inibidores , Produtos do Gene gag do Vírus da Imunodeficiência Humana/genética , Linhagem Celular , Farmacorresistência Viral/genética , Células HEK293 , Humanos , Fator de Transcrição Sp1/genética , Succinatos/farmacologia , Triterpenos/farmacologia , Montagem de Vírus/efeitos dos fármacos , Replicação Viral/efeitos dos fármacosRESUMO
OBJECTIVE: The aim of this study was to identify the association of parental MTHFR C677T gene polymorphism in couples with and without RPL history. RESULTS: During the study, 21.4% (15/70) of Ala222Val polymorphism was observed among RPL couples while no polymorphism was seen among normal, healthy couples. Our study did not find any association between MTHFR C677T polymorphism and gender (p > 0.05), gestational period (p > 0.05), geographical region (p > 0.05) and menstrual history (p > 0.05). However, significant association was seen between MTHFR C677T polymorphism and number of losses (p < 0.05), concluding that the risk of the polymorphism increased with the increase in number of losses. Significant variation in the MTHFR C677T genotype with number of losses among RPL couples were seen but not with other study variables.