Optimizing IMPDH inhibitors for the treatment of cryptosporidiosis

优化 IMPDH 抑制剂治疗隐孢子虫病

• 批准号: 8905204
• 负责人: Gregory D Cuny
• 金额: $ 69.74万
• 依托单位: UNIVERSITY OF HOUSTON
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8905204
• 关键词: Acquired Immunodeficiency Syndrome; Acute; Address; Adult; Affect; Age-Years; Anabolism; Animal Model; Antiparasitic Agents; Bacteria; Biological Assay; Biological Warfare; Bioterrorism; Cell Culture Techniques; Cells; Child; Chronic; Colon Carcinoma; Communities; Cryptosporidiosis; Cryptosporidium; Cryptosporidium parvum; Cytosol; Diarrhea; Disease; Disease Outbreaks; Drug Exposure; Drug Kinetics; Drug Targeting; Drug or chemical Tissue Distribution; Enteral; Enzymes; Epidemic; Epithelial Cells; Evaluation; Excretory function; FDA approved; Gastroenteritis; Gastrointestinal Diseases; Gastrointestinal tract structure; Genes; Genetic; Genomics; Goals; Growth; Guanine Nucleotides; Health; Histopathology; Horizontal Gene Transfer; Human; IMP Dehydrogenase; Immunocompromised Host; In Vitro; Individual; Infection; Inhibitory Concentration 50; Inosine 5' -Phosphate Dehydrogenase Inhibitor; Intestinal parasite; Intestines; Lateral; Liver Microsomes; Malnutrition; Mediating; Metabolism; Methods; Modeling; Molecular Target; Mus; Oocysts; Oral; Oral Administration; Organism; Orthologous Gene; Parasites; Pathway interactions; Patients; Pharmaceutical Preparations; Pharmacodynamics; Population; Positioning Attribute; Property; Proteobacteria; Protozoan Infections; Purines; Recycling; Research; Resistance; Risk; Series; Terrorism; Toxic effect; Vaccine Therapy; Vaccines; Vacuole; Validation; Water Supply; Work; absorption; analog; combat; commensal microbes; design; drug development; drug distribution; functional group; gastrointestinal; gastrointestinal system; in vivo; in vivo Model; inhibitor/antagonist; microbiome; mouse model; pre-clinical; programs; purine; scaffold; tool; treatment strategy; uptake; water treatment

DESCRIPTION (provided by applicant): Cryptosporidium species, including C. parvum and C. hominis, are protozoan parasites that present a health threat particularly to immunocompromised individuals and young children. These organisms are also potential bio-terrorism agents that could incapacitate large populations. Current treatment options are limited. Commonly used antiparasitic drugs are ineffective, the only FDA-approved drug is poorly efficacious, and vaccines are unavailable. Genomic analysis has revealed that Cryptosporidium species rely on inosine 5'- monophosphate dehydrogenase (IMPDH) for producing guanine nucleotides and, hence, survival. It also appears that the parasite obtained its IMPDH gene from an ε-proteobacterium by lateral transfer, so C. parvum IMPDH (CpIMPDH) is highly diverged from the human orthologs. Therefore, selective CpIMPDH inhibitors may provide an effective strategy for the treatment of cryptosporidiosis with minimum toxicity to the patient. To date, several structurally distinct classes of CpIMPDH inhibitors have been identified that have demonstrated excellent enzymatic potency, selectivity over human IMPDH, anti-parasitic activity in a cell culture model and, for one compound series, in vivo efficacy in an acute cryptosporidiosis mouse model. The overall goals of this proposed study are to further refine CpIMPDH inhibitors to achieve efficacy in both acute and chronic mouse models of cryptosporidiosis to support the hypothesis that selective CpIMPDH inhibition is a viable treatment strategy for this protozoan infection, provide guidance for the research community with respect to optimal compound properties for in vivo efficacy and provide further pre-clinical validation of CpIMPDH as a molecular target. These goals will be achieved by pursuing three specific aims: 1) design, synthesis and in vitro evaluation of CpIMPDH inhibitors in assays of CpIMPDH inhibitory potency and selectivity, a C. parvum cell culture infection model and ADME properties (including mouse and human intestinal and liver microsome stability, cellular uptake, efflux and toxicity, and UGT-mediated glucuronidation); 2) assess the in vivo pharmacokinetic and acute toxicity properties of CpIMPDH inhibitors, including in vivo models of oral absorption and tissue distribution in both non-infected and C. parvum infected mice; 3) evaluate optimized CpIMPDH inhibitors in acute and chronic animal models of cryptosporidiosis assessing fecal oocyst excretion and gastrointestinal gross and histopathology. In addition, the impact of CpIMPDH inhibitors on commensal bacteria populations will also be examined to more fully evaluate pharmacodynamics effects, since many bacteria have IMPDHs that are similar to CpIMPDH. This project will also develop strategies for limiting drug distribution to the gastrointestinal tract. Since this strategy could be applicable to other gastrointestinal diseases, such as irritable bowel disease and colon cancer, this work has broad implications beyond the treatment of cryptosporidiosis.

描述（由申请人提供）：隐孢子虫物种，包括小隐孢子虫和人隐孢子虫，是原生动物寄生虫，尤其对免疫功能低下的个体和幼儿构成健康威胁。这些生物体也是潜在的生物恐怖主义媒介，可能使大量人口丧失活动能力。目前的治疗选择有限。常用的抗寄生虫药物效果不佳，FDA唯一批准的药物效果不佳，而且还没有疫苗。基因组分析表明，隐孢子虫物种依赖肌苷 5'-单磷酸脱氢酶 (IMPDH) 来产生鸟嘌呤核苷酸，从而生存。该寄生虫似乎还通过横向转移从 ε-变形菌获得了其 IMPDH 基因，因此 C. parvum IMPDH (CpIMPDH) 与人类直系同源物高度不同。因此，选择性CpIMPDH抑制剂可能为治疗隐孢子虫病提供一种对患者毒性最小的有效策略。迄今为止，已鉴定出几种结构不同的 CpIMPDH 抑制剂，这些抑制剂表现出优异的酶效力、对人 IMPDH 的选择性、细胞培养模型中的抗寄生虫活性，以及​​对于一种化合物系列，在急性隐孢子虫病小鼠模型中的体内功效。这项拟议研究的总体目标是进一步完善 CpIMPDH 抑制剂，以在隐孢子虫病的急性和慢性小鼠模型中实现疗效，以支持选择性 CpIMPDH 抑制是这种原生动物感染的可行治疗策略的假设，为研究界提供有关体内功效的最佳化合物特性的指导，并为 CpIMPDH 作为治疗药物提供进一步的临床前验证。 分子靶标。这些目标将通过追求三个具体目标来实现：1）设计、合成和体外评估 CpIMPDH 抑制剂，以测定 CpIMPDH 抑制效力和选择性、微小念珠菌细胞培养感染模型和 ADME 特性（包括小鼠和人类肠道和肝脏微粒体稳定性、细胞摄取、外排和毒性以及 UGT 介导的葡萄糖醛酸化）； 2) 评估 CpIMPDH 抑制剂的体内药代动力学和急性毒性特性，包括未感染和小隐孢子虫感染小鼠的口服吸收和组织分布的体内模型； 3) 在隐孢子虫病的急性和慢性动物模型中评估优化的 CpIMPDH 抑制剂，评估粪便卵囊排泄以及胃肠道大体和组织病理学。此外，还将检查 CpIMPDH 抑制剂对共生细菌群体的影响，以更全面地评估药效学效果，因为许多细菌具有与 CpIMPDH 相似的 IMPDH。该项目还将制定限制药物分布到胃肠道的策略。由于该策略可能适用于其他胃肠道疾病， 除了治疗隐孢子虫病之外，这项工作还具有广泛的意义。