APEs as novel drug targets in AIDS opportunistic pathogen Toxoplasma

APEs作为艾滋病机会病原体弓形虫的新药物靶点

• 批准号: 7458665
• 负责人: William J Sullivan
• 金额: $ 22.29万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7458665
• 关键词: Acquired Immunodeficiency Syndrome; Address; Advanced Practice Nurse; Adverse effects; Affect; Animal Model; Apicomplexa; Area; Bacteria; Base Excision Repairs; Biological Assay; Biology; Categories; Cells; Characteristics; Chemicals; Core Facility; Cryptosporidium; DNA Damage; DNA Repair; DNA repair protein; Disease; Drug Delivery Systems; Encephalitis; Enzymes; Exhibits; Growth; Homologous Gene; Human; Immunocompromised Host; Investigation; Knock-out; Letters; Libraries; Lucanthone; Malaria; Mammals; Molecular; National Institute of Allergy and Infectious Disease; Opportunistic Infections; Parasites; Parasitology; Pathway interactions; Patients; Personal Satisfaction; Pharmaceutical Preparations; Physiology; Plasmodium; Plasmodium malariae; Play; Positioning Attribute; Preclinical Drug Evaluation; Probability; Protein Biochemistry; Protozoa; Public Health; Recombinants; Research; Role; Testing; Therapeutic; Therapeutic Agents; Therapeutic Studies; Toxic effect; Toxoplasma; Toxoplasma gondii; Validation; Work; biodefense; drug development; endonuclease; enzyme activity; fungus; high throughput screening; human APEX1 protein; inhibitor/antagonist; interest; killings; mutant; novel; pathogen; research study; response; small molecule

DESCRIPTION (Provided by Applicant): New drugs against parasitic protozoa of phylum Apicomplexa are urgently needed. Significant threats include Plasmodium (malaria), Cryptosporidium (diarrheal disease), and Toxoplasma (toxoplasmic encephalitis). The latter two are on the NIAID list of pathogens of interest for Biodefense, but are also serious opportunistic infections in AIDS. We have launched an investigation to study the therapeutic potential of Toxoplasma homologues of apurinic/apyrimidinic (AP) endonuclease, a key enzyme in the DNA base excision repair (BER) pathway. Toxoplasma possesses two distinct types of AP endonuclease that have attributes making them worthy candidates for drug development: TgAPE, which is divergent from its human homologue, and TgAPN, a type not found in mammals. We have found that a known inhibitor of human APE1, lucanthone, results in a significant reduction in Toxoplasma growth. However, because Toxoplasma has both APE and APN homologues, it will be necessary to establish the functional roles of these two enzymes in order to successfully develop therapeutic agents. There are three possibilities with regard to the functional roles of Toxoplasma APE and APN enzymes: (1) TgAPE is the primary AP endonuclease required for BER (2) TgAPN is the primary AP endonuclease, or (3) both enzymes play important roles in Toxoplasma. We propose to establish the contributions of the TgAPE and TgAPN enzymes by using chemical biology and conditional knockouts to address our hypothesis that Toxoplasma AP endonucleases will serve as good drug targets. Aim 1 will identify compounds that selectively inhibit TgAPE and TgAPN for target validation. To identify candidate inhibitors, we will pursue a high-throughput screen in our core facility. We have already generated recombinant TgAPE and TgAPN, and the assay for drug screening has been established, putting us in an excellent position to complete these studies. The specific inhibitors will permit a pharmacological approach to validate TgAPE and TgAPN as drug targets. Aim 2 will determine the impact of TgAPE and TgAPN on parasite physiology using conditional knockouts. These mutant lines will allow us to determine if TgAPE and/or TgAPN are essential for parasite viability. We will also be able to assess which of these AP endonucleases functions as the primary enzyme (or determine if both are equally important) by evaluating the conditional knockout's response to DNA damaging agents. It is in the interest of public health to investigate novel drugs and drug targets against Toxoplasma gondii, a serious opportunistic parasite of AIDS and other immunosuppressed patients. Toxoplasma is also listed by NIAID as a category B pathogen relevant to Biodefense research. Moreover, Toxoplasma can be informative as a model organism to study Plasmodium, the causative agent of malaria.

描述（申请人提供）： 迫切需要针对顶复门寄生原生动物的新药。重大威胁包括疟原虫（疟疾）、隐孢子虫（腹泻病）和弓形虫（弓形虫脑炎）。后两种属于 NIAID 生物防御感兴趣的病原体清单，但也是艾滋病中严重的机会性感染。我们开展了一项研究，研究弓形虫脱嘌呤/脱嘧啶 (AP) 核酸内切酶同源物的治疗潜力，脱嘌呤/脱嘧啶 (AP) 核酸内切酶是 DNA 碱基切除修复 (BER) 途径中的关键酶。弓形虫拥有两种不同类型的 AP 核酸内切酶，这些特性使它们成为值得药物开发的候选者：TgAPE（与其人类同源物不同）和 TgAPN（一种在哺乳动物中未发现的类型）。我们发现已知的人类 APE1 抑制剂硫蒽酮可显着减少弓形虫的生长。然而，由于弓形虫同时具有 APE 和 APN 同源物，因此有必要确定这两种酶的功能作用，以便成功开发治疗药物。关于弓形虫 APE 和 APN 酶的功能作用，存在三种可能性：(1) TgAPE 是 BER 所需的主要 AP 内切核酸酶 (2) TgAPN 是主要 AP 内切核酸酶，或 (3) 两种酶在弓形虫中均发挥重要作用。我们建议通过使用化学生物学和条件敲除来确定 TgAPE 和 TgAPN 酶的贡献，以解决我们的假设，即弓形虫 AP 核酸内切酶将作为良好的药物靶点。目标 1 将鉴定选择性抑制 TgAPE 和 TgAPN 的化合物以进行靶标验证。为了确定候选抑制剂，我们将在我们的核心设施中进行高通量筛选。我们已经生成了重组 TgAPE 和 TgAPN，并且药物筛选的测定方法也已经建立，使我们处于完成这些研究的绝佳位置。特定抑制剂将允许药理学方法验证 TgAPE 和 TgAPN 作为药物靶点。目标 2 将使用条件敲除确定 TgAPE 和 TgAPN 对寄生虫生理学的影响。这些突变系将使我们能够确定 TgAPE 和/或 TgAPN 是否对寄生虫的生存能力至关重要。我们还能够通过评估条件敲除对 DNA 损伤剂的反应来评估这些 AP 核酸内切酶中的哪一个作为主要酶（或确定两者是否同等重要）。研究针对弓形虫（艾滋病和其他免疫抑制患者的严重机会性寄生虫）的新药物和药物靶标符合公共卫生利益。弓形虫也被 NIAID 列为与生物防御研究相关的 B 类病原体。此外，弓形虫可以作为模式生物来研究疟疾的病原体疟原虫。

项目成果

Toxoplasma H2A variants reveal novel insights into nucleosome composition and functions for this histone family.

弓形虫 H2A 变体揭示了对该组蛋白家族核小体组成和功能的新见解。

• 发表时间: 2009-09-11
• 影响因子: 5.6
• 作者: Dalmasso, Maria C.;Onyango, David O.;Naguleswaran, Arunasalam;Sullivan, William J., Jr.;Angel, Sergio O.
• 通讯作者: Angel, Sergio O.