Lacritin Regulated Ocular Surface Homeostasis

泪泌素调节眼表稳态

• 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
• 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

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）：“Lacritin”是人泪液中的眼特异性促分泌和促存活因子。在人类干眼泪液中已经报道了选择性催泪素缺乏。在这里，我们测试的假设，催泪素是一个关键的调节器的角膜感觉神经活动的基础流泪，眼表代谢的生存压力。重要 这一假设的含义是活性催泪素的缺乏可能引发干眼症，并且局部催泪素可能是治疗性的。我们最近报道了治疗患有水缺乏性干眼病的小鼠。给予催乳素的自身免疫调节因子（Aire）缺陷[Aire-/-]小鼠显示出增强的泪液流量和眼表健康。催泪素还减少泪腺炎症。在正常的兔子眼睛上，我们发现单剂量的催泪素有效时间长达数小时。我们在大鼠中的新的电生理学研究显示，局部催泪素增强角膜感觉神经的基础泪液刺激性“干反应”。干燥反应由TRPM 8阳离子通道调节，TRPM 8阳离子通道敏锐地感知由于眼睛干燥的自然趋势而导致的轻微角膜冷却。从催泪蛋白的C-末端（“C-25”）截短25个氨基酸消除了干燥反应刺激和撕裂，这意味着细胞靶向的能力存在于该结构域内。我们最近发现，合成产生的结构域KQFIENGSEFAQKLLKKFS（“N-94/C-6”）与lacritin一样有效，并与细胞表面硫酸乙酰肝素蛋白聚糖“syndecan-1”和肾上腺素能2C受体特异性相互作用。这一发现表明了一种神经调节机制，因为肾上腺素能<$2C和/或<$2A受体调节TRPM 8活性。我们刚刚报道了催泪蛋白如何恢复炎症细胞因子应激的角膜上皮细胞的眼表功能。通过依赖于长寿因子'Forkhead Box 03'（FOXO 3）和鲜为人知的'ATG 101'的信号通路，lacritin刺激线粒体氧化磷酸化和自噬。自噬是细胞中常见的质量控制机制。ATG 101的结合伙伴表明了催泪素加速自噬和恢复线粒体功能的机制（分别通过自噬介体ATG 13和线粒体ETFA）。我们的工作假设是，催泪素是必不可少的正常流泪，眼表和腺体的健康。我们的近期目标是阐明催泪素刺激流泪和眼表健康的统一机制。我们的具体目标是（1）稳定N-94/C-6或更小的合成形式的催泪素，（2）表征局部催泪素如何促进基底流泪，以及（3）解决催泪素如何恢复眼表健康。弗吉尼亚大学夏洛特维尔分校 弗吉尼亚麦迪逊大学哈里森堡弗吉尼亚大学旧金山加州弗朗西斯科加州托马斯杰斐逊大学费城宾夕法尼亚