Lacritin Regulated Ocular Surface Homeostasis

泪泌素调节眼表稳态

基本信息

批准号：
8672811
负责人：
Gordon William Laurie
金额：
$ 47.48万
依托单位：
UNIVERSITY OF VIRGINIA
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-05-01 至 2018-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8672811
关键词：
Adrenergic Agents Adrenergic Receptor Amino Acids Autoimmune Process Autophagocytosis Binding Biological Assay Boxing California Cations Cell Culture Techniques Cell surface Cells Cellular Stress Cornea Coupling Dose Enzymes Epithelial Cells Eye Eye diseases Goals Health Heparan Sulfate Proteoglycan Homeostasis Hour Human Inflammation Inflammatory Lacrimal gland structure Longevity Mediator of activation protein Metabolic Metabolism Mitochondria Molecular Molecular Chaperones Monitor Mus Oryctolagus cuniculus Oxidative Phosphorylation Pennsylvania Peptide Hydrolases Philadelphia Play Quality Control Rattus Reporting Ribosomes Role San Francisco Sensory Signal Pathway Stress Testing Therapeutic Time Tissues Transglutaminases Translations Universities Up-Regulation Validation Virginia Work adrenergic afferent nerve aqueous corneal epithelium crosslink cytokine density eye dryness mouse model mutant neurophysiology ocular surface receptor relating to nervous system response syndecan synthetic peptide

项目摘要

DESCRIPTION (provided by applicant): 'Lacritin' is an ocular specific prosecretory and prosurvival factor in human tears. Selective lacritin deficiency has been reported in human dry eye tears. Here we test the hypothesis that lacritin is a key regulator of corneal sensory nerve activity for basal tearing, and of ocular surface metabolism for survival against stress. Important implications of this hypothesis are that deficiency of active lacritin may initiate dry eye disease and that topical lacritin may be therapeutic. We recently reported on treating mice suffering from aqueous deficient dry eye disease. Autoimmune regulator (Aire)-deficient [Aire-/-] mice dosed with lacritin displayed enhanced tear flow and ocular surface health. Lacritin also reduced lacrimal gland inflammation. On normal rabbit eyes, we found that a single lacritin dose was effective for hours. Our new electrophysiological studies in rats reveal that topical lacritin enhances the basal tear stimulatory 'dry response' of corneal sensory nerves. The dry response is regulated by TRPM8 cation channels that exquisitely sense slight corneal cooling as a consequence of the natural tendency of the eye to dessicate. Truncating 25 amino acids from lacritin's C- terminus ('C-25') abrogated dry response stimulation and tearing, implying that the capacity for cell targeting resides within this domain. We recently found that the domain generated synthetically as KQFIENGSEFAQKLLKKFS ('N-94/C-6') is as potent as lacritin, and interacts specifically with the cell surface heparan sulfate proteoglycan 'syndecan-1', and with the adrenergic ¿2C receptor. This discovery suggests a neural regulatory mechanism since adrenergic ¿2C and/or ¿2A receptors modulate TRPM8 activity. We just reported how lacritin restores ocular surface function in corneal epithelial cells stressed with inflammatory cytokines. Through a signaling pathway dependent of the longevity factor 'Forkhead Box 03' (FOXO3) and on the little known 'ATG101', lacritin stimulates mitochondrial oxidative phosphorylation and autophagy. Autophagy is a common quality control mechanism in cells. Binding partners of ATG101 suggest mechanisms by which lacritin accelerates autophagy and restores mitochondrial function (respectively through autophagy mediator ATG13, and mitochondrial ETFA). Our working hypothesis is that lacritin is essential for normal tearing, and ocular surface and glandular health. Our immediate goal is to elucidate unifying mechanisms of lacritin stimulated tearing and ocular surface health. Our specific aims are to (1) stabilize N-94/C-6 or smaller synthetic form of lacritin, (2) characterize how topical lacritin promotes basal tearing, and (3) resolve how lacritin restores ocular surface health. University of Virginia Charlottesville Virginia James Madison University Harrisonburg Virginia University of California, San Francisco San Francisco California Thomas Jefferson University Philadelphia Pennsylvania

描述（由申请人提供）：“泪泌素”是人类泪液中的一种眼部特异性促分泌因子和促存活因子，据报道，在人类干眼泪液中存在选择性泪泌素缺乏。在此，我们检验了泪泌素是角膜感觉神经活动的关键调节剂的假设。对于基础泪液和眼表代谢对于抵抗压力很重要。这一假设的含义是，缺乏活性泪泌素可能会引发干眼病，而我们最近报道了治疗患有水性自身免疫调节因子 (Aire) 缺乏的小鼠的干眼病。服用乳泌素的小鼠表现出泪液流动增强和眼表健康，并且在正常兔眼中，我们发现单剂量的乳泌素可在数小时内有效。大鼠表明，局部泪液素可增强角膜感觉神经的基础泪液刺激“干燥反应”，这种干燥反应是由 TRPM8 阳离子通道调节的，该通道能够敏锐地感觉到由于眼睛自然干燥倾向而导致的轻微角膜冷却。来自乳泌素 C 末端（“C-25”）的酸消除了干反应刺激和撕裂，这意味着细胞靶向能力位于该域内。发现合成生成的结构域 KQFIENGSEFAQKLLKKFS ('N-94/C-6') 与乳泌素一样有效，并且与细胞表面硫酸乙酰肝素蛋白聚糖 'syndecan-1' 以及肾上腺素能 ¿ 2C 受体。这一发现表明肾上腺素能 ¿ 以来的神经调节机制。 2C 和/或 ¿我们刚刚报道了泪泌素如何通过依赖于长寿因子“Forkhead Box 03”（FOXO3）和鲜为人知的“ATG101”的信号通路恢复受到炎症细胞因子应激的角膜上皮细胞的眼表功能。泪蛋白刺激线粒体氧化磷酸化和自噬是细胞中常见的质量控制机制。提出了泪泌素加速自噬和恢复线粒体功能的机制（分别通过自噬介质 ATG13 和线粒体 ETFA）。我们的工作假设是，泪泌素对于正常泪液、眼表和腺体健康至关重要。我们的具体目标是 (1) 稳定 N-94/C-6 或更小的合成形式的乳泌素。 (2) 描述局部泪泌素如何促进基底撕裂，以及 (3) 解决泪泌素如何恢复眼表健康。弗吉尼亚州詹姆斯·麦迪逊大学哈里森堡弗吉尼亚州加利福尼亚大学旧金山分校加利福尼亚州旧金山托马斯·杰斐逊大学费城宾夕法尼亚州