Inhibition of fatty acid amide hydrolase as a novel strategy to prevent nephrotoxicity of cisplatin.

肾毒性是顺铂的主要剂量限制性毒性，顺铂是许多固体药物的有效一线疗法。 恶性肿瘤。顺铂引起的肾损伤的机制尚不完全清楚，也没有有效的治疗方法 目前已有管理策略。内源性大麻素（EC）系统最初被 专注于中枢神经系统，在包括肾脏在内的周围器官中也发挥着重要作用。 最充分表征的 EC 是花生四烯酸乙醇胺 (AEA) 和 2-花生四烯酰甘油 (2-AG)。生物合成 AEA 的产生是通过 N-花生四烯酰-磷脂酰-乙醇胺通过至少三种不同的水解 生物合成途径。 2-AG 由二酰基甘油脂肪酶产生，可水解含有 2-花生四烯酰基的 二酰基甘油（DAG）生成2-AG。生产后，EC 与局部大麻素受体（CB1 和 CB2)以自分泌或旁分泌方式。研究表明 EC 系统参与不同的肾脏 疾病，包括顺铂引起的肾毒性（CIN），并且 CB 受体的干预是有希望的 治疗策略。令人惊讶的是，大多数研究都集中在 CB 受体上，而对其作用知之甚少。 ECs 肾脏损害中的代谢酶。解决这一重大差距非常重要，而且势在必行 研究 ECs 酶在肾脏疾病中的作用。最近的一项研究表明，在接受顺铂治疗的小鼠中， AEA显着升高，而2-AG在肾脏中无变化，抑制CB1受体 减轻顺铂引起的肾功能障碍，表明内源性大麻素系统通过 CB1 受体促进顺铂引起的肾损伤。我们最初打算测试 FAAH 抑制是否有效， 导致 AEA 水平升高，会加重 CIN。令人惊讶的是，CIN 在 FAAH KO 小鼠，表明 AEA 水平的增加实际上对 CIN 具有保护作用。 AEA 海拔 FAAH 抑制后的水平也可能导致 AEA-FAAH 衍生的花生四烯酸 (AA) 和 AEA-COX2 衍生的前列腺酰胺水平增加。我们的初步数据表明，保护 FAAH 抑制剂可被底物选择性 COX2 抑制剂 LM4131 逆转（抑制 AEA-COX2，而非 AA- COX2)，但不是通过补充 AA，也不是通过阻断 CB 受体。根据以上信息， 待检验的假设是 FAAH 抑制可通过 AEA-COX2 衍生的途径保护肾脏免受 CIN 的侵害 前列腺酰胺。提出以下目标来检验假设。目的1：确定是否抑制 FAAH 可以保护肾脏免受 CIN 的侵害。研究将使用遗传和药理学以及系统性方法 以及针对 FAAH 抑制的肾脏靶向方法。目标2：确定AEA-COX2是否衍生 前列腺酰胺是 FAAH 抑制后负责肾脏保护的下游信号通路 CIN。目标 3：确定抑制 FAAH 不会干扰顺铂的抗肿瘤作用。的 这些拟议研究的结果表明，抑制 FAAH 是治疗该疾病的新策略。 CIN 的预防和治疗。

Nephrotoxicity is a primary dose-limiting toxicity for cisplatin, a potent first-line therapy for many solid malignancies. The mechanistic basis for cisplatin-induced kidney damage is not fully understood and no efficient management strategies are currently available. The endocannabinoid (EC) system, which has been initially focused on the central nervous system, also plays important roles in the peripheral organs, including the kidneys. The most well-characterized ECs are anandamide (AEA) and 2-arachidonoylglycerol (2-AG). The biosynthesis of AEA is through the hydrolysis of N-arachidonoyl-phosphatidyl-ethanolamines via at least three distinct biosynthetic routes. The 2-AG is produced by diacylglycerol lipases, which hydrolyze 2-arachidonoyl-containing diacylglycerols (DAG) to generate 2-AG. After production, ECs bind to the local cannabinoid receptors (CB1 and CB2) in an autocrine or paracrine manner. It has been shown that EC system participates in different kidney diseases, including cisplatin-induced nephrotoxicity (CIN), and that interventions of CB receptors are promising therapeutic strategies. Surprisingly, majority of studies focus on CB receptors, and little is known about roles of ECs metabolic enzymes in kidney damages. It is important to address this significant gap and imperative to investigate the role of ECs enzymes in kidney diseases. A recent study showed that in cisplatin-treated mice, AEA was significantly increased while 2-AG had no change in the kidneys and that inhibition of CB1 receptors attenuated the cisplatin-induced renal dysfunction, suggesting that endocannabinoid system through CB1 receptors promotes cisplatin-induced kidney injury. We initially intended to test whether FAAH inhibition, which results in increased levels of AEA, would aggravate the CIN. Surprisingly, CIN was dramatically attenuated in FAAH KO mice, suggesting that the increased levels of AEA is actually protective in CIN. The elevation of AEA levels after FAAH inhibition could also result in reduced levels of AEA-FAAH-derived arachidonic acid (AA) and increased levels of AEA-COX2-derived prostamides. Our preliminary data demonstrated that the protection by FAAH inhibitor was reversed by the substrate-selective COX2 inhibitor LM4131 (inhibits AEA-COX2, not AA- COX2), but not by the supplementation of AA, nor the blocking CB receptors. Based on the above information, the hypothesis to be tested is that FAAH inhibition protects the kidneys against CIN via AEA-COX2-derived prostamides. The following Aims are proposed to test the hypotheses. Aim 1: To determine whether inhibition of FAAH protects the kidneys against CIN. Studies will use genetic and pharmacological as well as both systemic and kidney-targeted approaches for FAAH inhibition. Aim 2: to determine whether AEA-COX2-derived prostamides are the downstream signaling pathway responsible for the renoprotection after FAAH inhibition in CIN. Aim 3: To establish that inhibition of FAAH will not interfere with the antitumor actions of cisplatin. The findings from these proposed studies will suggest that inhibition of FAAH is new therapeutic strategy for the prevention and treatment of CIN.