Lacritin Regulated Ocular Surface Homeostasis

泪泌素调节眼表稳态

• 批准号: 9060945
• 负责人: Gordon William Laurie
• 金额: $ 45.81万
• 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/9060945
• 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; Electrophysiology (science); Enzymes; Epithelial Cells; Eye; Eye diseases; FOXO3A gene; 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; 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”是人类泪液中的一种眼部特异性促分泌和促存活因子。据报道，人类干眼泪液选择性缺乏催泪素。在这里，我们检验了这样的假设：泪泌素是基底撕裂的角膜感觉神经活动的关键调节剂，以及抵抗压力的眼表代谢的关键调节剂。重要的 这一假设的含义是，缺乏活性催乳素可能引发干眼病，而局部催乳素可能具有治疗作用。我们最近报道了治疗患有水液缺乏性干眼病的小鼠。自身免疫调节剂 (Aire) 缺陷的 [Aire-/-] 小鼠服用乳泌素后，泪液流量和眼表健康状况均得到改善。泪素还可以减少泪腺炎症。在正常兔子的眼睛上，我们发现单剂量的催乳素可在数小时内有效。我们对大鼠进行的新电生理学研究表明，局部泪泌素可增强角膜感觉神经的基底泪液刺激“干反应”。干燥反应由 TRPM8 阳离子通道调节，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。从乳泌素的 C 末端（“C-25”）截断 25 个氨基酸可消除干反应刺激和撕裂，这意味着细胞靶向的能力位于该结构域内。我们最近发现，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 TRPM8 活性。我们刚刚报道了泪泌素如何恢复受到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”(FOXO3) 和鲜为人知的“ATG101”的信号通路，乳泌素可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。 ATG101 的结合伴侣表明了乳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，泪泌素对于正常流泪、眼表和腺体健康至关重要。我们的近期目标是阐明乳泌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乳泌素，(2) 表征局部乳泌素如何促进基底撕裂，以及 (3) 解决乳泌素如何恢复眼表健康。弗吉尼亚大学夏洛茨维尔分校 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