Structure and Function of Ocular Lacritin

眼泪素的结构和功能

基本信息

批准号：
7648042
负责人：
Gordon William Laurie
金额：
$ 38.18万
依托单位：
UNIVERSITY OF VIRGINIA
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-08-01 至 2012-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7648042
关键词：
AQP1 gene Acinar Cell Address Adverse effects Agonist Anti-Inflammatory Agents Binding Biological Assay Blepharitis Calcineurin Calcineurin inhibitor Calcium Calcium Signaling Carbachol Cell Culture Techniques Cell Proliferation Cell physiology Cell surface Complex Contact Lenses Cornea Crystallins Cyclosporine Cyclosporins Distal Dose Down-Regulation Drug Design Drug Prescriptions Dry Eye Syndromes Elements Epithelial Epithelial Cells Epithelium Event Eye Eye diseases Female G Protein-Coupled Receptor Genes G Protein-Coupled Receptor Signaling G-Protein-Coupled Receptors Goals Golgi Apparatus Heart Human INS 365 Insulin Ligation Lung Membrane Molecular Monkeys Muramidase Mutation Oryctolagus cuniculus Pancreas Pathway interactions Patients Peroxidases Pharmaceutical Preparations Phosphotransferases Production Proliferating Protein Phosphatase G Proteins Proteoglycan RNA Splicing Rattus Receptor Signaling Research Role Secretory Vesicles Serum Signal Transduction Small Interfering RNA Structure T-Lymphocyte Therapeutic Treatment Protocols Up-Regulation Variant Work analog base cell type corneal epithelium eye dryness feeding heparanase human FRAP1 protein lacrimal meibomian gland novel ocular surface protein protein interaction public health relevance receptor small molecule syndecan tear proteins

项目摘要

DESCRIPTION (provided by applicant): Our competitive renewal application addresses dry eye from the perspective of the new ocular-specific tear factor 'lacritin' discovered by us. Lacritin flows onto the ocular surface from lacrimal and meibomian glands to help promote ocular surface wetting. It is also a presumed contributor to corneal renewal via its basal corneal epithelial expression. Selective downregulation of lacritin in tears is associated with blepharitis and contact lens-related dry eye, the only two dry eye syndromes proteomically examined to date. Adding lacritin to eyes of normal rabbits or dry eye female monkeys ovariectomized one to two years earlier triggers elevated and sustained tear flow. These observations are reinforced by human corneal epithelial cell culture in which lacritin stimulates MUC16 protein production more efficiently than serum and by our original observation that lacritin augments tear peroxidase release from cultured rat lacrimal acinar cells independent of the parasympathetic- (carbachol-) stimulation pathway. Also subconfluent cultures of human corneal epithelial cells proliferate in a lacritin domain- and dose-specific manner. How lacritin promotes tearing and renewal is not understood. Our lacritin structure/function and lacritin signaling studies have sketched out a heparanase-dependent mechanism for targeting cell surface proteoglycan syndecan-1. This leads to putative ligation of a G-protein coupled receptor for signaling through G1i or G1o to PLC-PKC1/PLD/mTOR and PLC- PKC1/STIM1/calcineurin/Ca2+/ NFATC1. Differential upregulation of newly identified splice variants lacritin-b or -c (suspected to be incapable of respectively binding the GPCR or syndecan-1) coincident with downregulation of native lacritin, or loss of heparanase (observed preliminarily in dry eye tears) are two potential dry eye-provoking scenarios. Our working hypothesis is that lacritin is a regulator of ocular surface wetting and renewal. Our immediate goal is to characterize the signaling receptor and understand its mechanism of action. Our first aim is to understand specific protein-protein interactions constituting the lacritin/syndecan-1/G-protein coupled receptor heterocomplex. Our second aim is to characterize how upstream lacritin signaling is generated. Our third aim asks how downstream lacritin signaling can promote wetting and renewal towards a global appreciation for lacritin's role on the ocular surface. PUBLIC HEALTH RELEVANCE. Dry eye is very common. This project will work out how a new potential therapeutic for dry eye promotes ocular surface wetting. The therapeutic is based on a natural human tear protein.

描述（由申请人提供）：我们的竞争性更新应用从我们发现的新型眼部特异性泪液因子“lacritin”的角度解决干眼问题。泪素从泪腺和睑板腺流到眼表面，有助于促进眼表面湿润。它也被认为是通过其基底角膜上皮表达促进角膜更新的因素。泪液中泪泌素的选择性下调与睑缘炎和隐形眼镜相关的干眼症有关，这是迄今为止经过蛋白质组学检查的仅有的两种干眼综合征。将催泪素添加到一到两年前切除卵巢的正常兔子或干眼雌性猴子的眼睛中，会引发泪液流量增加和持续。这些观察得到了人角膜上皮细胞培养物的强化，其中泪泌素比血清更有效地刺激MUC16蛋白的产生，并且我们最初的观察发现，泪泌素增强了培养的大鼠泪腺腺细胞泪液过氧化物酶的释放，不依赖于副交感神经（卡巴胆碱）刺激途径。人角膜上皮细胞的亚汇合培养物也以泪泌素结构域和剂量特异性方式增殖。乳泌素如何促进流泪和更新尚不清楚。我们的泪泌素结构/功能和泪泌素信号传导研究已经勾勒出一种靶向细胞表面蛋白聚糖 syndecan-1 的乙酰肝素酶依赖性机制。这导致假定连接有 G 蛋白偶联受体，通过 G1i 或 G1o 向 PLC-PKC1/PLD/mTOR 和 PLC-PKC1/STIM1/钙调神经磷酸酶/Ca2+/NFATC1 发出信号。新鉴定的剪接变体lacritin-b或-c（怀疑无法分别结合GPCR或syndecan-1）的差异上调与天然lacritin的下调或乙酰肝素酶的丧失（初步在干眼泪液中观察到）一致是两种潜在的情况引发干眼症的场景。我们的工作假设是，泪泌素是眼表湿润和更新的调节剂。我们的近期目标是表征信号受体并了解其作用机制。我们的首要目标是了解构成lacritin/syndecan-1/G-蛋白偶联受体杂复合物的特定蛋白质-蛋白质相互作用。我们的第二个目标是表征上游泪泌素信号传导是如何产生的。我们的第三个目标是询问下游泪泌素信号如何促进润湿和更新，以实现全球对泪泌素在眼表作用的认识。公共卫生相关性。干眼症很常见。该项目将研究一种新的潜在干眼疗法如何促进眼表湿润。该疗法基于天然的人类泪液蛋白。