O-Glycan Synthesis: Potential Targets for Intervention in Cryptosporidiosis

O-聚糖合成：干预隐孢子虫病的潜在目标

• 批准号: 8496716
• 负责人: Honorine D Ward
• 金额: $ 22.42万
• 依托单位: TUFTS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8496716
• 关键词: AIDS therapy; Acetylgalactosamine; Acquired Immunodeficiency Syndrome; Affinity; Alcohol or Other Drugs use; Antibodies; Binding; Biological Assay; Cell Communication; Cells; Collaborations; Cryptosporidiosis; Cryptosporidium; Cryptosporidium parvum; Data; Development; Disease; Emerging Communicable Diseases; Enzyme Inhibitor Drugs; Enzyme Inhibitors; Enzymes; Epithelial Cells; Funding; Future; Genes; Genome; Glycobiology; Glycoproteins; Goals; Immune response; Immunocompromised Host; In Vitro; Infection; Intervention; Intestines; Invaded; Lectin; Link; Mediating; Molecular; Monoclonal Antibodies; Mucins; New England; Parasites; Parasitology; Patients; Peptides; Pharmaceutical Chemistry; Pharmaceutical Preparations; Play; Polysaccharides; Proteins; Publishing; Recombinants; Resources; Role; Surface; System; Technology; Testing; Therapeutic; Toxoplasma gondii; Transferase; United States National Institutes of Health; Universities; base; biodefense; effective therapy; enzyme activity; high throughput screening; inhibitor/antagonist; novel; polypeptide; ppGalNAc-T; screening; small molecule; small molecule libraries; sugar

DESCRIPTION (provided by applicant): The opportunistic apicomplexan parasite Cryptosporidium (Crypto) causes diarrheal disease worldwide which can be devastating in AIDS patients. However, currently, there is no effective, specific therapy for AIDS- associated cryptosporidiosis. The long term goal of this project is to develop therapeutics for cryptosporidiosis in AIDS patients by targeting enzymes that synthesize O-glycans that are integral to the ability of the parasite to attach to and invade intestinal epithelial cells. Our previous and preliminary studies strongly suggest that O- glycans play a significant role in mediating infection and inducing immune responses and imply that the enzymes (UDP-N-acetyl-D-galactosamine: polypeptide N-acetylgalactosaminyl transferases or ppGalNAc-Ts) which synthesize them may serve as targets for intervention for cryptosporidiosis in the immunocompromised, particularly AIDS patients. However, very little, if anything is known about these enzymes in Crypto. Our central hypothesis is that ppGalNAc-Ts that catalyze the synthesis of O-glycans on key mucin-type glycoproteins are essential for Crypto infection. The specific aim is to elucidate the functional role of ppGalNAc-Ts in Crypto infection using inhibitor identified by high throughput screening (HTS) of small molecule libraries in collaboration with National Small Molecule Screening and Medicinal Chemistry (NSRB) Core at the New the England Regional Center of Excellence for Biodefense and Emerging Infectious Diseases (NERCE-BEID). The most potent inhibitors of enzyme activity will be screened for their ability to specifically block synthesis of Crypto O-glycans. These inhibitors will then be tested for their ability to inhibit Crypto infection in vitro. At the completion of this project we expect to have expressed enzymatically active, recombinant forms of all four Cp GalNAc Ts and to have identified small molecule inhibitors which block enzyme activity, O-glycan synthesis and infection in vitro. These studies will establish the role of O-glycans and the enzymes that catalyze their synthesis in Crypto-host cell interactions and significantly advance the field. Results from this project will inform future studies on Crypto ppGalNAc-Ts and O glycans on specific glycoproteins that are critical for mediating attachment to and invasion of host cells by the parasite. Small molecule inhibitors which block Crypto ppGalNAc T enzyme activity, O-glycan synthesis and infection in vitro can be developed as potential therapeutics for AIDS-associated cryptosporidiosis in future studies.

描述（由申请人提供）： 机会主义的Apicomplexan寄生虫隐孢子虫（加密）在全球范围内引起腹泻病，这可能是艾滋病患者造成的。但是，目前，尚无有效的，具有辅助孢子孢子虫病的特异性疗法。该项目的长期目标是通过靶向合成寄生虫与寄生虫与肠道上皮细胞相连和入侵肠道上皮细胞的能力的酶来开发艾滋病患者隐孢子虫病的治疗剂。我们以前的和初步的研究强烈表明，o-聚糖在介导感染和诱导免疫反应中起着重要作用，并暗示酶（UDP-N-乙酰-D-乳糖胺：多肽N-乙酰乳糖苷基因氨基转移酶或PPGALNAC-TS的范围），从而可以与ppgalnac-ts相结合，从而与免疫功能低下，特别是艾滋病患者。但是，很少，如果对这些酶有任何了解，则在加密货币中有任何了解。我们的中心假设是，催化O-聚糖在关键的粘蛋白型糖蛋白上的PPGALNAC-TS对于加密蛋白感染至关重要。具体目的是使用小分子文库的高吞吐量筛选（HTS）鉴定出PPGALNAC-TS在加密感染中的功能作用。最有效的酶活性抑制剂将被筛选，以特异性阻断加密糖糖的合成能力。然后，将对这些抑制剂的体外抑制加密感染的能力进行测试。在完成该项目时，我们期望所有四种CP GalNAC TS的酶活性，重组形式，并鉴定出了阻断酶活性，O-甘糖合成和体外感染的小分子抑制剂。这些研究将确定O-Glycans的作用和催化其在加密宿主宿主相互作用中的合成并显着推进该领域的酶。该项目的结果将为对特定糖蛋白的加密PPGALNAC-TS和O聚糖的未来研究提供信息，这些研究对于介导寄生虫对宿主细胞的附着和侵袭至关重要。在未来的研究中，可以开发出阻断加密PPGALNAC T酶活性，O-聚糖合成和体外感染的小分子抑制剂，在未来的研究中可以开发为潜在的治疗疗法。

项目成果

Molecular cloning, expression, and characterization of UDP N-acetyl-α-d-galactosamine: Polypeptide N-acetylgalactosaminyltransferase 4 from Cryptosporidium parvum.

UDP N-乙酰-α-d-半乳糖胺的分子克隆、表达和表征：来自小隐孢子虫的多肽 N-乙酰半乳糖胺基转移酶 4。

• DOI: 10.1016/j.molbiopara.2018.03.002
• 发表时间: 2018
• 期刊: Molecular and biochemical parasitology
• 影响因子: 1.5
• 作者: DeCiccoRePass,MariaA;Bhat,Najma;Heimburg-Molinaro,Jamie;Bunnell,Stephen;Cummings,RichardD;Ward,HonorineD
• 通讯作者: Ward,HonorineD