Solving EPHX2 and PUFA Interactions in Anorexia Nervosa

 描述(申请人提供)：神经性厌食症(AN)的特征是严格限制进食和消瘦，发病率、慢性病和死亡率都很高。目前的治疗方法具有很高的复发率和复发率，因此开发新的和改进的治疗方法是精神和公共卫生领域的高度优先事项。虽然A是高度可遗传的，但识别 由于缺乏对基因如何与非遗传风险因素相互作用的充分了解，病理生理学中的风险基因及其相关机制尚未取得成功。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。我们将使用膳食挑战研究设计来研究可溶性环氧化物水解酶(SEH)--AN易感基因EPHX2的基因产物--如何影响精神病理学和预后，以阐明EPHX2影响AN的机制。SEH是影响生物活性代谢产物(称为氧化脂质)的脂质信号功能的关键酶。它通过将多不饱和脂肪酸(PUFAs)的抗炎环氧化物(PUFAs)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患者的脂代谢紊乱和体内sEH活性升高(通过氧脂比率评估)。在体重恢复的AN中，体内sEH标志物的增加持续存在，进一步支持了我们的假设，即EPHX2调节sEH活性，从而诱导促炎氧脂转移，因此sEH升高可能不仅有助于易感性，而且可能与病程和结果有关。验证这一假说很重要，因为如果发现是真的，sEH活性可能会作为一个有用的生物标记物来预测疾病结果和指导治疗发展。多不饱和脂肪酸是氧化脂质的前体，因此多不饱和脂肪酸可能会影响sEH对氧化脂质的调节效率。AN患者对肉基脂肪食物(富含ω-6多不饱和脂肪酸)的强烈反感是众所周知的，我们发现AN患者膳食中ω-6：ω-3多不饱和脂肪酸的比例降低，提示AN患者EPHX2脂体途径的失调可能受其多不饱和脂肪酸摄入量的影响。因此，我们将检验这一假设，即在患者中，由于sEH活性的增加，氧磷脂的代谢受到干扰，并且干扰的程度是多不饱和脂肪酸依赖的，导致更多的食物厌恶，更高的精神病理学负担和不良的结果。在目标1中，我们将测试神经性厌食症患者的EPHX2代谢途径是否通过富含ω-6的早餐挑战而改变。在目标2中，我们将通过检测体外sEH活性来评估EPHX2基因与风险的关系，从而强调EPHX2基因的基本生化和分子机制。我们还将鉴定EPHX2变异体，以检测EPHX2非同义SNPs(NsSNPs)对体外sEH活性的影响。在目标3中，我们将利用餐前和餐后的精神病理特征和3个月的结果数据，通过纵向设计来评估sEH在疾病过程和结果中的作用。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提供对发病机制的见解，该方案将揭示遗传和饮食因素如何协同工作，对风险、表型和结果产生影响。这项研究的结果将揭开EPHX2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，并为未来的营养和制药开发带来新的靶点。

 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.