Sex-specific Regulation of Acute Inflammation and Resolution

描述(由申请人提供)：关于雌激素在免疫和炎症反应中的复杂作用，存在着极大的兴趣和尚未解决的矛盾。尽管干眼综合征主要影响女性，但性别差异和雌激素在眼部炎症性疾病中的作用尚不清楚。雌激素受体ER1和ER2在白细胞和每个眼组织中都有表达。急性健康炎症依赖于中性粒细胞的早期募集，它们的激活受到严格控制，随后被募集的巨噬细胞清除。这种基本反应的失调很可能是引发炎症和慢性疾病的早期事件。脂氧素A4(LXA4)被认为是炎症消退和白细胞功能调节的关键介质。角膜高度表达LXA4形成的关键酶15-脂氧合酶(15-LOX)及其G蛋白偶联受体ALX。15-LOX/LXA4循环的基因破坏导致角膜炎症、伤口愈合和病理性血管生成的失调。初步研究表明，雌性小鼠持续表现出延迟的上皮伤口闭合。一项对120名角膜溃疡患者进行的前瞻性临床试验首次发现，女性患者的角膜上皮伤口愈合速度是女性患者的两倍。雌性小鼠伤口延迟愈合的表型可以通过外用雌激素和体外角膜上皮细胞实验来概括。更重要的是，ER1和ER2特异性激动剂对炎症、上皮损伤愈合和15-LOX/LXA4内源性通路的表达和活性有不同的调节作用。这些发现与干眼模型的脂质学分析相关联，该模型显示雌性小鼠的角膜15-LOX活性显著受损。雌激素对这种内源性脂质循环的选择性调节可能为性别特异性眼表炎症性疾病的病因或发病机制提供新的见解，这将在三个特定的目标中进行测试：1.表征急性和复发性角膜上皮损伤和炎症过程中内在15-LOX和LXA4循环的性别差异。II.阐明雌激素受体(ER1和ER2)在调节角膜上皮细胞和白细胞创伤愈合功能中的作用，并确定这些细胞中15-LOX和LXA4回路的受体特异性调节。III.阐明ER1和ER2在干眼症小鼠角膜发病机制中的作用，并明确15-LOX和LXA4内源性通路的保护作用。这项研究的结果将解决关于雌激素及其受体在眼睛急性炎症/修复反应中的作用的关键知识空白，并将首次确定对炎症消退至关重要的内在脂环的性别特异性(雌激素)调节。我们对LXA4的结构、功能关系、受体和信号转导途径以及相关的模拟物的知识相对较高，并且已经在动物模型中建立了有效性/安全性。因此，这项研究的结果可能会迅速为临床带来治疗眼表炎症性疾病的新选择。 公共卫生相关性：这项研究将解决有关雌激素及其受体在眼睛急性炎症/修复反应中的作用的关键知识空白，并将首次确定对炎症消退至关重要的内在脂环的性别特异性(雌激素)调节。由于内源性保护性脂质介质的先进药理学和明确的靶点，本研究结果可能会迅速为临床带来治疗眼表炎症性疾病的新选择。

DESCRIPTION (provided by applicant): There is a great interest and unresolved paradox regarding the complex role of estrogen in immune and inflammatory responses. Sex-specific differences and estrogen's role in ocular inflammatory diseases are not well understood, even though Dry Eye Syndromes primarily affect women. Receptors for estrogens, ER1 and ER2, are expressed in leukocytes and in every ocular tissue. Acute healthy inflammation depends on the early recruitment of neutrophils, their tightly controlled activation and subsequent removal by recruited macrophages. Dysregulation of this essential response likely represent the early event that triggers inflammatory and chronic diseases. The lipid mediator lipoxin A4 (LXA4) has been identified as key mediator of inflammatory resolution and regulators of leukocyte function. The cornea highly expresses a key enzyme for LXA4 formation, 15-lipoxygenase (15-LOX), and its G-protein coupled receptor ALX. Genetic disruption of the 15-LOX/LXA4 circuit leads to dysregulated inflammation, wound healing and pathological angiogenesis in the cornea. Preliminary studies demonstrate that female mice consistently exhibit delayed epithelial wound closure. A prospective clinical trial in 120 patients with corneal ulcers, documents for the first time, that epithelial wounds healed twice as slow in female patients. The female phenotype of delayed wound healing can be recapitulated by treating male mice with topical estrogen and in in vitro experiments with corneal epithelial cells. More importantly, ER1 and ER2 specific agonists differentially regulated inflammation, epithelial wound healing and the expression and activity of the intrinsic 15-LOX/LXA4 circuit. These findings correlate with lipidomic analysis from a dry eye model that demonstrates striking impairment in corneal 15-LOX activity in female mice. Estrogen's selective regulation of this intrinsic lipid circuit may provide novel insights into the etiology or pathogenesis of sex-specific ocular surface inflammatory diseases, which will be tested in three specific aims: I. Characterize sex-specific differences in the intrinsic 15-LOX and LXA4 circuit during acute and reoccurring epithelial injury and inflammation in the cornea. II. Elucidate the role of the estrogen receptors (ER1 and ER2) in the regulation of corneal epithelial and leukocyte wound healing function and define receptor specific regulation of the 15-LOX and LXA4 circuit in these cells. III. Delineate the role ER1 and ER2 in the corneal pathogenesis of dry eye in mice and define the protective role of the intrinsic 15-LOX and LXA4 circuit. Result from this study will address critical gaps of knowledge regarding the role of estrogen and its receptors in acute inflammatory/reparative responses in the eye and will define for the first time sex-specific (estrogen) regulation of intrinsic lipid circuits that are critical for inflammatory resolution. Our knowledge of structure function relationships, receptors and signal transduction pathways for LXA4 and related mimetics is relatively advanced and efficacy/safety in animal models have been established. Hence, results from this study could rapidly bring novel treatment options for ocular surface inflammatory diseases to the clinic. PUBLIC HEALTH RELEVANCE: This study will address critical gaps of knowledge regarding the role of estrogen and its receptors in acute inflammatory/reparative responses in the eye and will define for the first time sex-specific (estrogen) regulation of intrinsic lipid circuits that are critical for inflammatory resolution. Due to the advanced pharmacology and clearly defined targets of endogenous protective lipid mediators, results from this study could rapidly bring novel treatment options for ocular surface inflammatory diseases to the clinic.