N-glycosylation and ocular surface homeostasis

N-糖基化和眼表稳态

• 批准号: 9196100
• 负责人: Pablo Argueso
• 金额: $ 49.25万
• 依托单位: SCHEPENS EYE RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9196100
• 关键词: Address; Affect; Affinity; Aging; Anabolism; Animal Model; Apical; Automobile Driving; Binding; Biological Process; Cell Differentiation process; Cell Proliferation; Cell physiology; Cell surface; Cells; Cellular Stress; Clinical Treatment; Cornea; Critical Pathways; Data; Disease; Epithelial; Epithelial Cells; Epithelium; Extracellular Domain; Eye; Galectin 3; Genes; Glycocalyx; Health; Hexosamines; Homeostasis; Human; In Vitro; Inflammation; Inflammation Mediators; Inflammatory; Integrin alpha3beta1; Kinetics; Laboratories; Lectin; Longevity; Matrix Metalloproteinases; Medial Golgi; Mediating; Metabolic; Molecular; Mucins; Organism; Pathologic Processes; Pathway interactions; Pharmacological Treatment; Physiological; Physiological Processes; Polysaccharides; Prevention; Process; Proteins; Quality Control; RNA interference screen; Reaction; Regulation; Research; Role; Series; Signal Transduction; Structure; Supplementation; TNF gene; Therapeutic; Therapeutic Uses; Translating; abstracting; age related; base; biological adaptation to stress; conjunctiva; corneal epithelium; crosslink; defined contribution; endoplasmic reticulum stress; eye dryness; genome-wide; glycosylation; glycosyltransferase; improved; in vivo; mouse model; novel; novel therapeutics; ocular surface; prevent; receptor; receptor binding; research study; response; senescence

Project Summary/Abstract Disruption of barrier function at the ocular surface epithelia is associated with a wide range of disorders that includes dry eye—an age-related disease affecting millions of people worldwide and whose pharmacological treatment remains unresolved. Terminally differentiated stratified epithelial cells in cornea and conjunctiva maintain barrier function through a specialized protective structure composed of transmembrane mucins, a group of heavily glycosylated proteins characterized by extremely large extracellular domains. Galactosyl residues on mucin glycans are cross-linked on the apical glycocalyx by the multimeric protein galectin-3 to prevent cellular damage. Critical to preventing the decline in cellular function and homeostasis is the hexosamine pathway—a series of anabolic reactions that generate increased synthesis of N-glycan precursors. Activation of the hexosamine pathway leads to increased branching of N-glycans in the medial Golgi and the formation of cell-surface galectin-3 lattices that can modulate cell differentiation. Importantly, metabolic supplementation with hexosamine pathway metabolites is also known to enhance protein quality control mechanisms. Despite these critical roles, the relevance of N-glycosylation and the function of hesoxamine metabolites in ocular surface health and disease remains understudied. We hypothesize that N- glycans have a dynamic role in ocular surface epithelial cells, changing in response to inflammation and driving mucin barrier and stress responses. The long-term objective of this proposal is to determine the contribution of the N-glycan branching in promoting ocular surface health, and whether activation of the hexosamine pathway can be used for therapeutic gain in the eye. The following specific aims will address this objective: (1) to characterize mucin N-glycans in human corneal epithelial cells and their relationship to galectin-3 under normal and pro-inflammatory conditions, (2) to determine the regulatory role of N-glycans in promoting barrier function and reducing stress responses at the ocular surface, and (3) to evaluate whether activation of the hexosamine pathway promotes ocular surface homeostasis. This research will address the largely unstudied function of N-glycans in ocular surface barrier function and stress responses, and explore the potential of pharmacologically activating the hexosamine pathway for the treatment of ocular surface diseases.

项目总结/摘要 眼表面上皮细胞屏障功能的破坏与多种疾病有关， 包括干眼症-一种与年龄有关的疾病，影响全世界数百万人， 治疗仍然没有解决。角膜和结膜终末分化的复层上皮细胞 通过由跨膜粘蛋白组成的特殊保护结构维持屏障功能， 一组高度糖基化的蛋白质，以极大的细胞外结构域为特征。半乳糖 粘蛋白聚糖上的残基通过多聚体蛋白半乳糖凝集素-3在顶端糖萼上交联， 防止细胞损伤。防止细胞功能和稳态下降的关键是 己糖胺途径-一系列合成代谢反应，产生N-聚糖合成增加 前体己糖胺途径的激活导致中间体中N-聚糖的分支增加。 高尔基体和细胞表面半乳糖凝集素-3晶格的形成，可以调节细胞分化。重要的是， 还已知用己糖胺途径代谢物进行代谢补充可提高蛋白质质量 控制机制。尽管有这些关键作用，但N-糖基化的相关性和糖基化的功能仍然是未知的。 海索沙明代谢物在眼表健康和疾病中的作用仍有待研究。我们假设N- 聚糖在眼表上皮细胞中具有动态作用，在炎症反应中发生变化， 粘蛋白屏障和应激反应。本提案的长期目标是确定 N-聚糖分支在促进眼表健康中的作用，以及 该途径可用于眼睛中的治疗增益。以下具体目标将实现这一目标： (1)表征人角膜上皮细胞中的粘蛋白N-聚糖及其与半乳糖凝集素-3的关系， 正常和促炎性条件，（2）确定N-聚糖在促进屏障中的调节作用 功能和减少眼表面的应激反应，以及（3）评估是否激活了 己糖胺途径促进眼表稳态。这项研究将解决在很大程度上未研究的 N-聚糖在眼表屏障功能和应激反应中的作用，并探讨 激活己糖胺途径用于治疗眼表疾病。