A novel mechanism for rapid increase of brain prostanoid levels

描述（申请人提供）：前列腺素（PG）是调节许多生理和病理过程的重要信号分子。PG介导疼痛、发烧、炎症，并参与多种临床疾病的发展，包括癌症、炎症、神经退行性疾病、中枢神经系统损伤和神经精神疾病。然而，调节大脑PG水平的机制尚不清楚。我们的长期目标是了解大脑PG水平调节的机制，并概述用于治疗各种神经病理生理疾病的药物的潜在新治疗靶点。本应用的目的是阐明脑前列腺素在刺激后立即快速增加（<1分钟）的机制。在这个应用中，我们假设了一种新的PG释放途径。我们的中心假设是，前列腺素质量的快速增加是通过动员快速释放的预先形成的PG池而发生的，这些PG被发现酯化到磷脂上。我们在初步研究中提出的发现支持了这一假设。我们发现：1。PG被酯化成磷脂[注意这些不是异前列腺素]；2. 体内刺激后迅速释放酯化PG；3. 储存在磷脂上的PG来源于COX1/2；4. 外源添加的PG在细胞磷脂上酯化；5. 在炎症反应期间，花生四烯酸（20:4n-6）的释放并不需要PG质量的初始增加。前列腺素释放的新途径解决了与传统的PG释放途径相关的一些矛盾，并且与已知的PG在大脑中的快速形成更加一致。重要的是，我们提出的新途径是指刺激后组织反应早期PG质量增加的快速增加，而不是反对传统途径在组织反应后期的作用。然而，由于最初PG质量的快速增加可能引发随后的组织反应阶段，因此提出的PG释放的新途径无疑与PG形成的组织损伤反应的后期阶段有关。中心假设将通过以下特定目标进行验证：特定目标1：确定以酯化形式储存PG的脑细胞和组织的能力；特定目标2：确定负责从磷脂储存池中释放PG的酶系统；这项工作具有创新性，因为它研究了一种新的途径，可以将PG从预先形成的酯池释放到磷脂上，这是其他人以前没有研究过的。这些结果将具有重要意义，因为该项目的成功完成将加强目前关于脑PG水平调节的观点，并将揭示磷脂在PG释放中的新功能。此外，它将概述用于治疗各种神经病理生理疾病的药物的潜在新治疗靶点，并将增强我们对这些疾病的潜在机制的理解。公共卫生相关性：我们提出的工作的相关性在于，它研究了一种新的机制，通过将前列腺素从预先形成的酯化池释放到磷脂上，从而快速增加脑前列腺素水平，这是其他人以前没有研究过的。这一点很重要，因为前列腺素与大量神经退行性疾病有关。这些结果将具有重要意义，因为它们将加强目前关于脑前列腺素水平调节的传统观点，概述用于治疗各种神经病理生理疾病的药物的潜在新治疗靶点，并增强我们对这些疾病潜在机制的理解。

DESCRIPTION (provided by applicant): Prostanoids (PG) are important signaling molecules that regulate many physiological and pathological processes. PG mediate pain, fever, inflammation and are involved in the development of a broad range of clinical disorders including cancer, inflammation, neurodegenerative diseases, central nervous system injury, and neuropsychiatric conditions. However, the mechanism that regulates brain PG levels is poorly understood. Our long-term goal is to understand the mechanism underlying the regulation of brain PG levels and to outline potentially new therapeutic targets for drugs used in the treatment of a wide variety of neuropathophysiological conditions. The objective of this application is to elucidate the mechanisms accounting for the immediate, rapid increase (<1 min) in brain prostanoids upon stimulation. In this application, we hypothesize a novel pathway for PG release. Our Central Hypothesis is that the rapid increase in prostanoid mass occurs via mobilization of a rapidly releasable pool of preformed PG found esterified onto phospholipids. Our findings presented in the Preliminary Studies support this hypothesis. We found that: 1. PG are esterified onto phospholipids [Note these were not isoprostanes]; 2. esterified PG are rapidly released upon stimulation in vivo ; 3. PG stored on phospholipids are derived from COX1/2; 4. exogenously added PG are esterified onto cellular phospholipids; 5. arachidonic acid (20:4n-6) release is not required for this initial increase in PG mass during the inflammation response. The hypothesized novel pathway for prostanoid release addresses some of the contradictions associated with the traditional pathway of PG release and is more consistent with the known rapid formation of PG in brain. Importantly, our proposed novel pathway refers to the rapid increase in PG mass increase at early phase of tissue response upon stimulation, and does not argue against the role of traditional pathway at the late phases of tissue response. However, because the initial rapid increase in PG mass may trigger consequent phases of tissue response, the proposed novel pathway for PG release is undoubtedly linked to the later phases of tissue injury response with regards to PG formation. The central hypothesis will be tested by the following specific aims: Specific Aim 1: Determine the capacity of brain cells and tissue for PG storage in esterified form; Specific Aim 2: Determine enzymatic systems responsible for PG release from phospholipid storage pool; The proposed work is innovative because it examines a novel pathway for PG release from preformed pool esterified onto phospholipids that has not been previously addressed by others. These results will be significant because the successful completion of the project will enhance the current view regarding the regulation of brain PG levels and will reveal a new function for phospholipids in PG release. Also, it will outline potentially new therapeutic targets for drugs used in the treatment of a wide variety of neuropathophysiological conditions and will enhance our understanding of the mechanisms underlying these conditions. PUBLIC HEALTH RELEVANCE: The relevance of our proposed work is that it examines a novel mechanism for a rapid increase of brain prostanoid levels through prostanoid release from preformed pool esterified onto phospholipids that has not been previously addressed by others. This is important because of the association of prostanoids with a large number of neurodegenerative diseases. These results will be significant because they will enhance the current traditional view regarding the regulation of brain prostanoid levels, outline potentially new therapeutic targets for drugs used in the treatment of a wide variety of neuropathophysiological conditions, and enhance our understanding of the mechanisms underlying these conditions.