桦木酸的3 - O -（3'，3'-二甲基琥珀酰）衍生物（DSB）可抑制在表达HIV-1 Gag前体的细胞中病毒样颗粒的组装。

The 3-O-(3',3'-dimethylsuccinyl) derivative of betulinic acid (DSB) inhibits the assembly of virus-like particles in HIV-1 Gag precursor-expressing cells.

作者信息

DaFonseca Sandrina, Blommaert Armand, Coric Pascale, Hong Saw See, Bouaziz Serge, Boulanger Pierre

机构信息

Laboratoire de Virologie et Pathologie Humaine, Université de Lyon I and CNRS FRE-3011, Faculté de Médecine Laennec, 69372 Lyon 08, France.

出版信息

Antivir Ther. 2007;12(8):1185-203.

PMID:18240859

Abstract

BACKGROUND

The 3-O-(3',3'-dimethylsuccinyl) derivative of betulinic acid (DSB) blocks HIV-1 maturation by interfering with viral protease (PR) at the capsid (CA)-SP1 cleavage site, a crucial region in HIV-1 morphogenesis.

METHODS

We analysed the effect of DSB on the assembly of HIV-1 Gag precursor (Pr55Gag(HIV)) into membrane-enveloped virus-like particles (VLP) in baculovirus-infected cells expressing Pr55Gag(HIV), in a cellular context devoid of viral PR.

RESULTS

DSB showed a dose-dependent negative effect on VLP assembly, with an IC50 approximately 10 microM. The DSB inhibitory effect was p6-independent and was also observed for intracellular assembly of non-N-myristoylated Gag core-like particles. HIV-1 VLP assembled in the presence of DSB exhibited a lower stability of their inner cores upon membrane delipidation compared with control VLP, suggesting weaker Gag-Gag interactions. DSB also inhibited the assembly of simian immunodeficiency virus SLVmac251 VLP, although with a twofold lower efficacy (IC50 approximately 20 microM). No detectable inhibitory activity was observed for murine leukaemia virus (MLV) VLP; however, fusion of the SP1-NC-p6 domains from HIV-1 to the matrix (MA)-CA domains from MLV conferred DSB sensitivity to the chimaeric Gag precursor Pr72Gag(MLV-HIV) (IC50 = 30 microM). This observation suggested that the main DSB target on Pr55Gag was the SP1 domain, but the higher degree of DSB resistance for Pr72Gag(MLV-HIV) compared with Pr55Gag(HIV) implied that other upstream Gag region(s) might contribute to DSB reactivity.

CONCLUSIONS

Sequence alignment and three-dimensional modelling by homology of the CA-SP1-NC junction in HIV-1, SLVmac251 and Pr72Gag(MLV-HIV) suggested that a higher hydrophilic character of the CA region immediately upstream to the HIV-1 CA-SP1 junction, as occurred in Pr72Gag(MLV-HIV), correlated with a lower DSB sensitivity.

摘要

背景

桦木酸的3 - O -（3'，3'-二甲基琥珀酰）衍生物（DSB）通过干扰病毒蛋白酶（PR）在衣壳（CA）-SP1切割位点的作用来阻断HIV-1成熟，该位点是HIV-1形态发生中的关键区域。

方法

我们在表达Pr55Gag(HIV)的杆状病毒感染细胞中，在缺乏病毒PR的细胞环境下，分析了DSB对HIV-1 Gag前体（Pr55Gag(HIV)）组装成膜包裹的病毒样颗粒（VLP）的影响。

结果

DSB对VLP组装呈现剂量依赖性的负面影响，IC50约为10 microM。DSB的抑制作用不依赖于p6，在非N-肉豆蔻酰化Gag核心样颗粒的细胞内组装中也观察到该作用。与对照VLP相比，在DSB存在下组装的HIV-1 VLP在膜脱脂后其内核稳定性较低，表明Gag-Gag相互作用较弱。DSB也抑制了猴免疫缺陷病毒SLVmac251 VLP的组装，尽管效力低两倍（IC50约为20 microM）。未观察到对鼠白血病病毒（MLV）VLP有可检测的抑制活性；然而，将HIV-1的SP1-NC-p6结构域与MLV的基质（MA）-CA结构域融合赋予了嵌合Gag前体Pr72Gag(MLV-HIV)对DSB的敏感性（IC50 = 30 microM）。该观察结果表明Pr55Gag上DSB的主要靶点是SP1结构域，但与Pr55Gag(HIV)相比，Pr72Gag(MLV-HIV)对DSB的抗性更高，这意味着其他上游Gag区域可能影响DSB的反应性。