Lipid mediators and their signaling in ocular surface inflammation and meibomian gland dysfunction

干眼症(DE)影响五分之一的退伍军人，并影响生活质量。这是一种复杂的疾病，表现为 多种症状(如疼痛、视力障碍)和体征(如泪液分泌减少、增加 蒸发)。DE的主要病理生理成分是眼表炎症和眉板腺 功能障碍(MGD)。尽管它的频率和发病率，目前的治疗方法并不能完全缓解症状。 病人。为了恰当地管理DE，有必要了解机制和具体情况 疾病亚型的贡献者。这项建议的总体目标是通过研究提高这些知识 生物活性鞘脂(SPL)在MGD和DE的其他方面的作用。我们的初稿和出版 研究表明SPL的组成变化(较高的鞘磷脂(SM)/神经酰胺(Cer)比率)质量较差 眉板腺分泌物(MEIBUM)；较高的促炎(ω-6)/促分解(ω-3)脂类比率，以及 DE患者泪液中前列腺素E_2水平升高。从SM中产生生物活性Cer 鞘磷脂酶(SMase)及其衍生物、神经酰胺1-磷酸和1-磷酸鞘氨醇是 炎症脂质，并可诱导形成其他炎性脂类，如前列腺素。我们检测到 人眼泪中的酶活性。在这项提议中，我们将检验这样一个假设，即SPL成分的变化在 MEIBUM导致DE的各种征兆，包括眼表炎症、泪膜紊乱和 MGD.在目标1中，我们将分析meiburn和tear spl以及促炎和抗炎的PUFA和二十烷类化合物。 用LC-MS/MS对120例蜂蜜质量差的患者和120名正常人的蜂蜜质量进行分析。 经过全面的眼睛评估后，我们前瞻性地收集了大量退伍军人的样本 (平均年龄62±10岁；男性467人，女性46人；白人230人，黑人272人)。相关和回归分析将被 以临床资料为因变量，以血脂介质为自变量进行研究。在目标2中，我们 将从与样品相对应的240条Schirmer‘s试条中确定sMase的酸性(酸性和中性) 在目标1中，我们将建立模型，研究SMASE活性、SPL和眼表之间的关系 发炎。在目标3中，我们将在体外确定SPL和炎症之间的分子联系 用人永生化眉板腺上皮细胞系(HMGEC)建立模型，以检验丹参的作用 在正常和高渗条件下，SPL具有调节炎症、细胞活力、细胞死亡等的生物活性。 影响：我们的结果将根据MGD状态确定SPL的差异，阐明生物活性之间的关系 SPL、炎性脂质介质和SMase活性与眼表炎症及临床特征的关系 MGD和DE亚型。所产生的知识将通过确定相对的 不同血脂在DE不同表现中的作用，为开发新的DE提供基础 治疗的分子靶点。

Dry eye (DE) affects 1 in 5 veterans and impacts quality of life. It is a complex disease that manifests with multiple symptoms (e.g. pain, visual disturbance) and signs (e.g. decreased tear production, increased evaporation). Key pathophysiological components of DE are ocular surface inflammation and meibomian gland dysfunction (MGD). Despite its frequency and morbidity, current therapies do not relieve symptoms in all patients. In order to appropriately manage DE, it is necessary to understand mechanisms and specific contributors to disease sub-types. The overall goal of this proposal is to improve such knowledge by studying the role of bioactive sphingolipids (SPL) in MGD and other aspects of DE. Our preliminary and published work suggest SPL composition changes (higher sphingomyelin (SM)/ ceramide (Cer) ratio) in poor quality meibomian gland secretion (meibum); a higher ratio of pro-inflammatory (ω-6) /pro-resolving (ω-3) lipids, and higher levels of prostaglandin E2 in tears from DE patients. Bioactive Cer generated from SM by sphingomyelinases (SMase) and its derivatives, ceramide 1-phosphate and sphingosine 1-phosphate are inflammatory lipids and can induce formation of other inflammatory lipids such as prostaglandins. We detected SMase activity in human tears. In this proposal, we will test the hypothesis that changes in SPL composition in meibum contribute to various signs of DE including ocular surface inflammation, tear film disturbances, and MGD. In Aim 1, we will profile meibum and tear SPL and pro- and anti-inflammatory PUFAs and eicosanoids by LC-MS/MS from 120 cases (poor meibum quality) and 120 controls (normal meibum quality), chosen from our prospectively collected samples from a large veteran population after a comprehensive eye evaluation (mean age 62±10; 467 males, 46 females; 230 white, 272 black). Correlation and regression analysis will be performed with clinical data as dependent variables and lipid mediators as independent variables. In Aim 2, we will determine acitivity of SMAse (acidic and neutral) from 240 Schirmer's strips corresponding to the samples in Aim 1. We will then build models looking at relationships between SMase activity, SPL, and ocular surface inflammation. In Aim 3, we will identify molecular connections between SPL and inflammation in an in vitro model by using human immortalized meibomian gland epithelial cell line (HMGEC) to test the effects of bioactive SPL on mediating inflammation, cell viability, cell death etc. in normal and hyperosmolar conditions. Impact: Our results will identify SPL differences by MGD status, elucidate relationships between bioactive SPL, inflammatory lipid mediators, and SMase activity with ocular surface inflammation and clinical features of MGD and DE sub-types. The knowledge generated will advance the field by determining the relative contributions of different lipids on different manifestations of DE and provide the foundation for developing new molecular targets for therapy.