Selectively Manipulating Intestinal Glucuronidation to Alleviate Mycophenolate mofetil-induced Diarrhea

项目标题：选择性操作肠道葡萄糖醛酸化反应以减轻霉酚酸酯诱导的 腹泻 摘要：胃肠道内的葡萄糖醛酸化反应通常是酚类药物的一种解毒程序，用于治疗 其他器官上的疾病。对于这些药物中的许多，胃肠道中的葡萄糖醛酸化作用不足，导致 在下胃肠段(即回肠和结肠)过度蓄积药物而导致局部毒性(例如， 腹泻、便秘)。我们的长期目标是开发安全有效的试剂来选择性地操纵 在不影响血浆药物暴露的情况下，下消化道的葡萄糖醛酸化作用可促进局部脱毒 以及更好的治疗结果的有效性。在本申请中，我们建议使用霉酚酸酯 霉酚酸前体药物(MMF)用于预防器官移植患者的排斥反应，如 用模型药物来证明概念原理。临床研究表明，超过20%的器官 接受MMF治疗的移植患者患有慢性腹泻，这显著降低了患者的 生活质量和成倍的移植物损失率。在初步研究中，我们发现汉黄素和白杨素， 由于两种新的循环机制，两种化合物仅在下消化道有生物可用 我们最近发现，能有效减轻MMF所致的大鼠腹泻。体外研究表明， 汉黄连甲素可诱导催化甲孕酮的酶亚家族UGT1a代谢为甲孕酮-葡萄糖醛酸苷 (MPAG，无毒代谢物)。此外，体外研究表明，白杨素可以抑制UGT2B7，以及 酶的异构体催化MPA代谢成酰基-MPA-葡萄糖醛酸脂(AcMPAG，一种有毒的代谢物)。 大鼠的PK研究表明，汉黄素/白杨素与MMF联合给药并不改变血浆暴露 对免疫抑制的活性形式--甲孕酮。因此，我们假设有选择地和 器官靶向药物汉黄素和白杨素协同作用对大鼠肠内葡萄糖醛酸化的影响 能减少下肠道局部接触MPA和AcMPAG，以减轻MMF引起的腹泻 而不影响全身暴露于甲氧基苯丙氨酸。我们提出了两个具体的目标来验证我们的假设：(1)验证 WOG和CHRY的协同止泻作用及开发更有效的细胞给药方案 和动物模型(目标1)；和(2)确定Wog和CHRY的止泻作用机制 细胞和动物模型(目标2)。这个项目的成功完成将使我们能够证明 使用当地生物可利用的化合物促进下肠道的局部排毒。有选择地操纵 使用器官靶向制剂在特定器官中进行药物代谢是高度创新的，从而揭开了 胃肠道副作用管理的重要新范例。该项目将使PI能够 保持和扩大他在开发可回收的本地生物可用药物方面的创新研究。另外， 获得这一奖项将使PI不断吸引和培养来自不同背景的学生， 特别是来自代表性不足的少数群体，拥有多学科的知识和技术。

Project Title: Selectively Manipulating Intestinal Glucuronidation to Alleviate Mycophenolate mofetil-induced Diarrhea Abstract: Glucuronidation in the GI tract usually is a detoxification procedure for phenolic drugs used to treat diseases on the other organs. For many of these drugs, glucuronidation in the GI tract is insufficient, resulting in excessive drug accumulation in the lower GI segments (i.e., ileum and colon) to cause local toxicity (e.g., diarrhea, constipation). Our long-term goal is to develop safe and effective agents to selectively manipulating glucuronidation in the lower GI tract to boost local detoxification without compromising plasma drug exposure and efficacy for better therapeutic outcomes. In this application, we propose to use mycophenolate mofetil (MMF), a prodrug of mycophenolic acid (MPA) used to prevent rejection in organ transplant patients, as the model drug to prove the principle-of-concept. Clinical studies have shown that more than 20% of organ transplant patients with MMF treatment suffer from chronic diarrhea, which significantly downgrades patients' quality of lives and doubles graft loss incidence. In the preliminary study, we found that wogonin and chrysin, two compounds that are only bioavailable in the lower GI tract due to two novel recyclings mechanisms discovered by us recently, can effectively attenuate MMF-induced diarrhea in rats. In vitro studies showed that wogonin can induce UGT1A, a subfamily of enzymes catalyzing MPA to be metabolized into MPA-glucuronide (MPAG, a non-toxic metabolite). Additionally, in vitro studies showed that chrysin could inhibit UGT2B7, an enzyme isoform catalyzing MPA to be metabolized into Acyl-MPA-glucuronide (AcMPAG, a toxic metabolite). PK studies in rats showed that co-administration of wogonin/chrysin with MMF didn't alter the plasma exposure to MPA, the active form for immunosuppression. Therefore, we hypothesize that selectively and synergistically manipulating MPA intestinal glucuronidation by organ targeting agents wogonin and chrysin could reduce local exposure to MPA and AcMPAG in the lower gut to attenuate diarrhea induced by MMF without affecting systemic exposure to MPA. We propose two specific aims to test our hypothesis: (1) verify the synergistic anti-diarrheal effect of Wog and Chry and develop more effective dosing regimens using cells and animal models (Aim 1); and (2) determine the mechanism of diarrhea attenuation by Wog and Chry using cells and animal models (Aim 2). Successful completion of this project will allow us to prove the concept of boosting local detoxification in the lower gut using locally bioavailable compounds. Selectively manipulating drug metabolism in a specific organ using organ targeting agents is highly innovative, thus unraveling an important new paradigm on management of side effects in the GI tract. This project will allow the PI to maintain and expand his innovative research in developing recycled locally bioavailable drugs. Additionally, receiving this award will allow the PI to continuously attract and train students from different background, especially from under-represented minority populations, with multi-disciplinary knowledge and techniques.