Design of inhibitors targeted to the CD4 binding site on HIV-1 gp120

针对 HIV-1 gp120 上 CD4 结合位点的抑制剂的设计

• 批准号: 9199075
• 负责人: Asim K Debnath
• 金额: $ 76.68万
• 依托单位: NEW YORK BLOOD CENTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-02-15 至 2018-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9199075
• 关键词: AIDS prevention; AIDS therapy; Affinity; Agonist; Anti-HIV Agents; Antibodies; Antiviral Agents; Arginine; Aspartic Acid; Binding; Binding Sites; CD4 Antigens; Cell surface; Cells; Clinical Research; Collaborations; Complex; Computer Simulation; Data; Databases; Dissociation; Docking; Drug Design; Drug resistance; Electrostatics; Entropy; Evaluation; Glycoproteins; Goals; HIV Envelope Protein gp120; HIV-1; Half-Life; Hydrophobicity; Immunoglobulin Fragments; Infection; Intervention; Kinetics; Lead; Measures; Mediating; Molecular Conformation; Nature; Pharmaceutical Chemistry; Pharmaceutical Preparations; Phenylalanine; Positioning Attribute; Property; Receptor Cell; Reporting; Research; Resistance; Roentgen Rays; Role; Site; Sodium Chloride; Structure; Thermodynamics; Toxic effect; United States National Institutes of Health; Virus; base; clinically relevant; design; enthalpy; flexibility; glycosylation; improved; inhibitor/antagonist; innovation; interfacial; microbicide; mimicry; mutant; neutralizing antibody; next generation; novel; piperidine; pre-clinical; preclinical study; prevent; prophylactic; public health relevance; scaffold; screening; small molecule inhibitor; targeted treatment; virtual

DESCRIPTION (provided by applicant): The entry of HIV-1 into host cells is mediated by the binding of the envelope glycoprotein gp120 to the host cell receptor CD4. The structures of the gp120-CD4-17b complex indicate that the CD4 binding site (CD4BS) on gp120 is located in a hydrophobic cavity, termed "Phe43 cavity" where Phe43CD4 makes critical hydrophobic contacts. Studies of these structures also confirmed an important electrostatic interaction between Arg59CD4 and Asp368gp120. Similar structural mimicry of several potent broad neutralizing antibodies (bNAbs) has recently been reported. The highly conserved nature of the residues in the CD4BS of gp120 and their role in binding to CD4 and CD4BS targeted bNAbs validates this site as a promising target for therapeutic and prophylactic intervention. Despite th remarkable diversity of the HIV-1 envelope glycoprotein sequence, glycosylation and conformational flexibility, gp120 must retain conserved domains required for binding to CD4. However, the well-conserved CD4 binding site has yet to be exploited to its full potential as a target in designing drugs to prevent HIV-1 entry, which will be the focus of our research. We were the first to identify two small molecule inhibitors, NBD-556 and NBD-557, which target the CD4BS on gp120. These molecules show unprecedented ability to induce conformational changes in gp120 similar to that of CD4; thereby, acting as agonists. Recently, we solved the structure of NBD-556 in complex with the gp120 coree, confirming that NBD-556 binds to the cavity of gp120. We used this structure to design new leads with improved anti-HIV-1 activity. However, these lead compounds showed CD4 agonist properties. In additional studies, we confirmed that a newly designed lead, NBD-11021, is a CD4 antagonist. Moreover, a recent report showed that the bNAb PGV04 targets the CD4BS but induces distinct conformational changes in gp120 that are not recognized by the 17b antibody. PGV04 thus does not induce exposure of the coreceptor binding site, suggesting that it is a CD4 antagonist not an agonist. We hypothesize that lead compounds, including NBD-11021, can be optimized by incorporating the distinct binding features of PGV04 with gp120 to produce a more potent and selective new class of HIV-1 entry inhibitors with CD4 antagonist properties. The goals of the proposed studies will be accomplished by three highly integrated specific aims. In Aim-1, the leads will be optimized through structure-guided design and medicinal chemistry. In Aim-2, thermodynamic and kinetic properties such as enthalpy, entropy, on- and off-rates and binding affinity (KD) will be measured as well as their antiviral potency and toxicity. The x-ray structures of new inhibitors in complex with gp120 will be determined. In Aim-3, mechanism of action will be studied and the resistant mutants of the inhibitors will be selected. The data from these studies will be used in designing potent next-generation entry inhibitors that will potentially escape resistance and be clinically relevant. The long-term goal is to develop a new class of HIV-1 entry inhibitors for pre clinical and clinical studies.

描述（由申请人提供）：HIV-1进入宿主细胞是通过包膜糖蛋白gp120结合宿主细胞受体CD4介导的。gp120-CD4-17b复合物的结构表明gp120上的CD4结合位点（CD4BS）位于疏水腔，称为“Phe43腔”，在这里Phe43CD4进行关键的疏水接触。这些结构的研究也证实了Arg59CD4和Asp368gp120之间存在重要的静电相互作用。最近已经报道了几种有效的广泛中和抗体（bNAbs）的类似结构模仿。gp120的CD4BS残基的高度保守性质及其与CD4和CD4BS靶向的bNAbs结合的作用验证了该位点作为治疗和预防干预的有希望的靶点。尽管HIV-1包膜糖蛋白序列、糖基化和构象灵活性具有显著的多样性，但gp120必须保留与CD4结合所需的保守结构域。然而，保守的CD4结合位点尚未被充分利用，作为设计药物以防止HIV-1进入的靶点，这将是我们研究的重点。我们首先发现了两种小分子抑制剂NBD-556和NBD-557，它们靶向gp120上的CD4BS。这些分子显示出前所未有的诱导gp120构象变化的能力，类似于CD4；因此，作为激动剂。最近，我们解决了NBD-556与gp120核心的配合物结构，证实了NBD-556与gp120的空腔结合。我们使用这种结构来设计具有更高抗hiv -1活性的新导联。然而，这些先导化合物显示CD4激动剂的特性。在其他研究中，我们证实了一种新设计的先导剂NBD-11021是一种CD4拮抗剂。此外，最近的一份报告显示，bNAb PGV04靶向CD4BS，但诱导gp120的明显构象变化，而这些变化不被17b抗体识别。因此，PGV04不会诱导暴露于辅助受体结合位点，这表明它是一种CD4拮抗剂而不是激动剂。我们假设，包括NBD-11021在内的先导化合物可以通过结合PGV04与gp120的独特结合特性来优化，从而产生更有效和选择性的新型HIV-1进入抑制剂，具有CD4拮抗剂特性。拟议研究的目标将通过三个高度综合的具体目标来实现。在Aim-1中，将通过结构导向设计和药物化学对导联剂进行优化。在Aim-2中，将测量热力学和动力学性质，如焓、熵、开断率和结合亲和力（KD），以及它们的抗病毒效力和毒性。新型抑制剂的x射线结构