MUCINS OF THE OCULAR SURFACE

眼表面粘蛋白

• 批准号: 6630084
• 负责人: ILENE K. GIPSON
• 金额: $ 13.16万
• 依托单位: SCHEPENS EYE RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 1979
• 资助国家: 美国
• 起止时间: 1979-08-01 至 2005-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6630084
• 关键词: MCF7 cell; Sjogren's syndrome; apical membrane; basement membrane; cell differentiation; clinical research; cornea disorder; corneal epithelium; corneal stroma; enzyme linked immunosorbent assay; eye injury; gene expression; gene induction /repression; goblet cells; human subject; hypersensitivity; keratoconjunctivitis sicca; laboratory mouse; membrane activity; mucins; protein structure function; tear; tissue /cell culture; transcription factor; western blottings; wound healing

The mucus of the tear film is responsible for maintenance of fluid on the surface of the eye and for providing a microbe barrier to protect the eye from infection. Ocular surface diseases such as those of the dry eye type, vitamin A deficiency, ocular surface infections as well as allergic conjunctivits may involve mucus deficiency, disruption of the mucus layer, or discharge of large amounts of mucus. During the previous funding period, we demonstrated that three mucin genes are expressed by the ocular surface epithelium, two prevalent ones being the membrane- spanning mucin MUC4 and the goblet cell-specific mucin MUC5AC. We sequenced portions of MUC4 and developed probes, antibodies, and assay methods for both mucins that we now propose to use in four specific aims toward understanding aspects of the function and regulation of expression of these mucins on the ocular surface in normal and pathologic states. Aim I: Characterize two aspects of the membrane-spanning mucin MUC4 on the ocular surface. A. determine whether the mucin remains associated with the apical membrane glycocalyx or whether its extracellular domain is shed into the tear film. b. Test candidate inducers of MUC4 gene expression, based on presence of putative transcription factor binding sites identified from sequencing the MUC4 regulatory region and on preliminary data indicating their potential role in its regulation. Aim II: We hypothesize that conjunctival goblet cell differentiation is characterized by induction of expression of the MUC5AC gene and that such induction can be regulated by environmental stimuli as well as cellular effectors. We propose to: a. determine in a mouse model whether goblet cell differentiation/Muc5AC expression can be influenced by surface irritants, infections, or specific allergens; b. determine whether conjunctival goblet cell differentiation can be enhanced in vitro, based on demonstrated presence of regulatory elements in the promoter region of MUC5AC and on culture conditions known to affect gastrointestinal goblet cell differentiation. Aim III: Determine if MUC5AC has specific affinities for MUC4 and the bactericidal proteins prevalent in the tear film, lysozyme, and secretory IgA. Aim IV: Determine in a specific type of dry eye (Sjogren's syndrome), and in seasonal allergic conjunctivitis whether amounts of MUC4 and MUC5AC mRNA and protein differ from the normal population. We hypothesize that dry eye syndromes are characterized by loss of surface wetting due to reduced amounts of MUC5AC and MUC4 protein, whereas, allergic conjunctivitis is characterized by an increased amount of mucins to facilitate allergen removal.

泪膜粘液负责维持眼睛表面的液体并提供微生物屏障以保护眼睛免受感染。眼表疾病，例如干眼症、维生素A缺乏症、眼表感染以及过敏性结膜，可能涉及粘液缺乏、粘液层破坏或大量粘液排出。在之前的资助期间，我们证明了眼表上皮表达三种粘蛋白基因，其中两种常见的基因是跨膜粘蛋白MUC4和杯状细胞特异性粘蛋白MUC5AC。我们对 MUC4 的部分进行了测序，并开发了两种粘蛋白的探针、抗体和测定方法，我们现在建议将其用于四个具体目标，以了解正常和病理状态下这些粘蛋白在眼表面的功能和表达调节的各个方面。目标 I：表征眼表面跨膜粘蛋白 MUC4 的两个方面。 A.确定粘蛋白是否仍然与顶膜糖萼相关或其胞外结构域是否脱落到泪膜中。 b.根据通过对 MUC4 调控区测序鉴定出的推定转录因子结合位点的存在以及表明其在调控中的潜在作用的初步数据，测试 MUC4 基因表达的候选诱导剂。目标 II：我们假设结膜杯状细胞分化的特征是诱导 MUC5AC 基因的表达，并且这种诱导可以通过环境刺激以及细胞效应器来调节。我们建议：在小鼠模型中确定杯状细胞分化/Muc5AC表达是否会受到表面刺激物、感染或特定过敏原的影响； b.根据MUC5AC启动子区域中已证实的调节元件的存在以及已知影响胃肠道杯状细胞分化的培养条件，确定结膜杯状细胞分化是否可以在体外增强。目标 III：确定 MUC5AC 是否对 MUC4 以及泪膜中普遍存在的杀菌蛋白、溶菌酶和分泌型 IgA 具有特定的亲和力。目标 IV：确定特定类型的干眼症（干燥综合征）和季节性过敏性结膜炎中 MUC4 和 MUC5AC mRNA 和蛋白质的含量是否与正常人群不同。我们假设干眼综合征的特征是由于 MUC5AC 和 MUC4 蛋白数量减少而导致表面润湿性丧失，而过敏性结膜炎的特征是粘蛋白数量增加以促进过敏原的去除。