Solving EPHX2 and PUFA Interactions in Anorexia Nervosa

 描述（由申请人提供）：神经性厌食症（AN）的特征是严重限制进食和消瘦，发病率、慢性化和死亡率高。目前的治疗具有高复发率和复发率，因此开发新的和改进的疗法是精神和公共卫生的高度优先事项。虽然AN具有高度遗传性，但识别 风险基因和相关机制对AN病理生理学尚未成功，由于缺乏足够的知识，基因如何与非遗传风险因素相互作用。这项研究旨在填补这一重大知识空白，以开发更好的预防和治疗方法。我们将研究可溶性环氧化物水解酶（sEH），一个AN易感基因，EPHX 2的基因产物，如何影响AN的精神病理学和结果使用膳食挑战研究设计，以阐明EPHX 2影响AN的机制。 sEH是影响生物活性代谢物（称为氧化脂质）的脂质信号传导功能的关键酶。它通过将多不饱和脂肪酸（PUFA）的抗炎环氧化物转化为促炎氧脂来调节细胞炎症。在我们最近的研究中，我们确定了AN患者的脂质组学失调和体内sEH活性升高（通过氧化脂质比评估）。体重恢复的AN中体内sEH标记物的增加持续存在，进一步支持我们的假设，EPHX 2调节sEH活性，诱导促炎性氧脂素转变，因此升高的sEH不仅可能导致AN易感性，而且可能导致疾病过程和结果。检验这一假设是重要的，因为如果发现是真的，sEH活性可能作为一个有用的生物标志物来预测疾病的结果和指导治疗的发展。 PUFAs是oxlipins的前体，因此PUFAs可能影响sEH对oxlipins的调节效率。众所周知，AN患者强烈厌恶肉类脂肪食物（富含ω-6 PUFA），我们已经证明AN患者的饮食ω-6：ω-3 PUFA比例降低，表明AN中EPHX 2脂质组学途径的失调可能受到PUFA摄入的影响。因此，我们将检验以下假设：在AN患者中，由于sEH活性的增加，氧脂代谢受到干扰，并且干扰的程度是PUFA依赖性的，导致食物厌恶增加，精神病理学负担更高，结果较差。在目标1中，我们将通过富含ω-6的早餐挑战来测试神经性厌食症中EPHX 2代谢组学途径是否改变。在目的2中，我们将强调EPHX 2基因的基本生物化学和分子机制，通过测定离体sEH活性来评估其与AN风险的关联。我们还将表征EPHX 2变体以检查EPHX 2非同义SNP（nsSNP）对离体sEH活性的影响。在目标3中，我们将利用餐前和餐后AN的精神病理学特征和3个月的结果数据，通过纵向设计来评估sEH在AN病程和结果中的作用。这项研究意义重大，因为它将通过使用创新的膳食挑战方案来深入了解AN发病机制，该方案将揭示遗传和饮食因素如何协同作用对AN风险，表型和结果产生影响。这项研究的结果将揭示EPHX 2影响AN的机制，提高我们预测疾病风险，监测疾病进展和治疗反应的能力，并为未来的营养和药物开发带来新的目标。

 DESCRIPTION (provided by applicant): Anorexia nervosa (AN) is characterized by severely restrictive eating and emaciation, with high rates of morbidity, chronicity and mortality. Current treatments have high rates of relapse and recurrence, thus developing new and improved therapies is a high priority in mental and public health. While AN is highly heritable, identifying risk genes and associated mechanisms on AN pathophysiology has yet to be successful due to the lack of adequate knowledge on how genes interact with non-genetic risk factors. This study aims to fill this major knowledge gap in order to develop better prevention and treatments. We will examine how soluble epoxide hydrolase (sEH), the gene product of an AN susceptibility gene, EPHX2, affects AN psychopathology and outcome using a meal-challenge study design to elucidate the mechanisms by which EPHX2 affects AN. sEH is a key enzyme that affects lipid signaling functions of bioactive metabolites (termed oxylipins). It modulates cellular inflammation by converting anti-inflammatory epoxides of polyunsaturated fatty acids (PUFAs) to pro-inflammatory oxylipins. In our recent study we identified dysregulated lipidomic profiles and elevated in vivo sEH activity (assessed by oxylipin ratios) in AN patients. The increase of the in vivo sEH marker persisted in weight-recovered AN, further supporting our hypothesis that EPHX2 regulates sEH activity that induces a pro-inflammatory oxylipin shift, therefore elevated sEH may contribute not only to AN susceptibility but also illness course and outcome. Testing this hypothesis is important because if found true, sEH activity may serve as a useful biomarker to predict disease outcome and guide treatment development. PUFAs are precursors of oxylipins, therefore PUFAs may affect regulatory efficiency of sEH on oxlipins. AN patients are known for their strong aversion to meat-based fatty foods (rich in ω-6 PUFA), and we have shown that dietary ω-6:ω-3 PUFA ratio is decreased in AN patients, suggesting that dysregulation of the EPHX2 lipidomic pathway in AN may be influenced by their PUFA intake. Thus, we will test the hypothesis that in AN patients, the metabolism of oxylipins is perturbed due to an increase in sEH activity, and the degree of perturbation is PUFA-dependent, resulting in increased food aversion, a higher burden of psychopathology, and poor outcome. In Aim 1 we will test if EPHX2 metabolomic pathways are altered in anorexia nervosa through a ω-6 rich breakfast challenge. In Aim 2 we will emphasize the fundamental biochemistry and molecular mechanism of EPHX2 gene by assaying ex vivo sEH activity to assess its association with AN risk. We will also characterize EPHX2 variants to examine the effects of the EPHX2 non-synonymous SNPs (nsSNPs) on ex vivo sEH activity. In Aim 3, we will utilize pre-meal and post-meal AN psychopathologic traits and 3-month outcome data to assess sEH's role in AN illness course and outcome through a longitudinal design. This study is significant because it will provide insights into AN pathogenesis by the use of an innovative meal challenge protocol that will reveal how genetic and dietary factor work in concert to exert effects on AN risk, phenotypes, and outcome. The results of this study will unravel mechanisms by which EPHX2 affects AN, improves our ability to predict disease risk, monitor disease progression and treatment response, and lead to new targets for future nutraceutical and pharmaceutical developments.