Mannosidase inhibitors as therapeutics for glycoprotein misfolding diseases

甘露糖苷酶抑制剂作为糖蛋白错误折叠疾病的治疗药物

• 批准号: 7474680
• 负责人: KELLEY W. MOREMEN
• 金额: $ 47.73万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-15 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7474680
• 关键词: Address; Adverse effects; Affinity; Alpha-mannosidase; Binding; Biochemical; Biochemistry; Biological Assay; Biological Models; Carbohydrates; Cell Maturation; Cell surface; Cells; Chemicals; Combinatorial Synthesis; Complex; Coupled; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Cytoplasm; Defect; Destinations; Disease; Disease model; Effectiveness; Endoplasmic Reticulum; Enzyme Inhibition; Enzymes; Estrogen Receptor alpha; Evaluation; Glycoproteins; Glycoside Hydrolases; Goals; Golgi Apparatus; Hereditary Disease; Human; In Vitro; Kinetics; Lead; Lectin; Libraries; Lysosomal Storage Diseases; Lysosomes; Mannose; Mannosidase; Medicine; Modeling; Modification; Molecular Chaperones; Mutation; NIH Program Announcements; Oligosaccharides; Pathology; Play; Polysaccharides; Process; Protein C Inhibitor; Protein Overexpression; Proteins; Quality Control; Rate; Recombinants; Research; Research Personnel; Role; Screening procedure; Signal Transduction; Specificity; Structure; Study models; Testing; Therapeutic; Time; USA Georgia; Universities; Western Asia Georgia; analog; base; college; combinatorial; cytotoxicity; enzyme activity; high throughput screening; human disease; inhibitor/antagonist; loss of function; mannosyl-oligosaccharide 1,2-alpha-mannosidase; mutant; novel therapeutics; polypeptide; programs; protein folding; protein misfolding; residence; response; small molecule; small molecule libraries; structural biology; virtual

DESCRIPTION (provided by applicant): The long-term goals of this application are to develop selective inhibitors for an ER glycoprotein processing enzyme that plays a key role in quality control in the endoplasmic reticulum (ER) as broad-based therapeutics for glycoprotein misfolding diseases. This enzyme, ERalpha-mannosidase I (ERManl), acts as a key timer for ER residence for newly synthesized glycoproteins by initiating a rate-limiting step leading to a cascade of interactions that ultimately leads to the targeting of terminally misfolded glycoproteins for retrotranslocation to the cytoplasm and proteasomal disposal in a process known as "ER-associated degradation" (ERAD). Many loss-of-function human genetic diseases result from mutations that cause delayed protein folding kinetics rather than generating terminally misfolded polypeptides. Recognition of the incompletely folded intermediates by the ERAD targeting machinery can lead to premature disposal of potentially functional glycoproteins and subsequently leads to pathology. Inhibition of the rate-determining steps in ERAD could provide a broad-based therapeutic approach for treatment of glycprotein misfolding diseases by delaying ERAD and providing sufficient time to complete the protein folding process. All of the known inhibitors of early mannose trimming steps, however, also have unacceptable serious side effects. They also inhibit glycan processing alpha-mannosidases in the Golgi complex and block maturation to complex type glycan structures on cell surface and secreted glycoproteins. Thus, the goals of this application are to identify selective ERManl inhibitors that can act to delay ERAD, rescue ER protein folding defects in human disease, and retain normal glycan maturation in the Golgi complex. The unique interdisciplinary team that we have assembled takes advantage of ongoing synergistic collaborative interactions between investigators at the University of Georgia and Baylor College of Medicine with expertise in the synthesis of selective glycosidase inhibitors (Boons), the biochemistry and structural biology of the ER and Golgi mannosidases (Moremen), and cell-based assays for a human glycoprotein misfolding disorder, alpha1-antitrypsin deficiency (Sifers). Promising leads will also be evaluated in established lysosomal storage disease models by collaborators (Amicus). Three specific aims are proposed including 1) the directed rational and combinatorial synthesis of analogs of alpha-mannosidase inhibitors with selectivity toward ERManl, 2) high-throughput screens combined with detailed biochemical and structural analysis to assess selectivity and effectiveness of the inhibitor compounds in blocking ERManl but not Golgi glycan maturation, and 3) cell-based assays to assess chemical chaperone effects of mannosidase inhibitors in the rescue of mutant alpha1-antitrypsin secretion and lysosomal enzyme targeting and without blockage of N-glycan maturation.

描述(申请人提供)：本申请的长期目标是开发一种选择性的ER糖蛋白处理酶抑制剂，该酶在内质网(ER)的质量控制中发挥关键作用，作为糖蛋白错误折叠疾病的广泛疗法。这种酶，ERpha-甘露糖苷酶I(ERManl)，通过启动限速步骤，导致一系列相互作用，最终导致靶向末端错误折叠的糖蛋白反向转位到细胞质和蛋白酶体处置，从而为新合成的糖蛋白提供内质网停留的关键计时器，这一过程被称为内质网相关降解(ERAD)。许多功能丧失的人类遗传病是由突变引起的，这些突变导致蛋白质折叠动力学延迟，而不是产生末端错误折叠的多肽。ERAD靶向机制识别不完全折叠的中间产物可能导致潜在功能糖蛋白的过早处置，并随后导致病理。抑制ERAD中的速率决定步骤可以通过延缓ERAD并提供足够的时间来完成蛋白质折叠过程，从而为糖蛋白错误折叠疾病的治疗提供一种广泛的治疗方法。然而，所有已知的早期甘露糖修剪步骤的抑制剂也都有不可接受的严重副作用。它们还抑制高尔基复合体中的糖链加工α-甘露糖苷酶，并阻止细胞表面复合型糖链结构和分泌的糖蛋白的成熟。因此，这项应用的目标是寻找选择性的ERManl抑制剂，这些抑制剂可以延缓ERAD，挽救人类疾病中的ER蛋白折叠缺陷，并保持高尔基复合体中正常的糖链成熟。我们组建的独特的跨学科团队利用了佐治亚大学和贝勒医学院的研究人员之间正在进行的协同合作互动，他们拥有合成选择性糖苷酶抑制剂(Boons)、内质网和高尔基甘露糖苷酶的生物化学和结构生物学(Moreman)以及人类糖蛋白错误折叠障碍--α1抗胰蛋白酶缺乏症(Sifers)的细胞分析方面的专业知识。有希望的线索也将由合作者(Amicus)在已建立的溶酶体储存疾病模型中进行评估。提出了三个具体目标，包括：1)直接、合理和组合地合成对ERMan1具有选择性的α-甘露糖苷酶抑制剂类似物；2)高通量筛选结合详细的生化和结构分析来评估抑制化合物在阻止ERMan1而不是高尔基多糖成熟方面的选择性和有效性；以及3)基于细胞的分析来评估甘露糖苷酶抑制剂在挽救突变的α1-抗胰蛋白酶分泌和溶酶体靶向性以及不阻断N-糖链成熟的情况下的化学伴侣效应。