晚期氧化蛋白产物上调JNK/ERK-p27信号诱导小肠上皮细胞G1期阻滞在克罗恩病中的作用及其机制

G1-phase arrest of intestinal epithelial cells(IEC) plays an important role in Crohn’s disease(CD), and it causes epithelial atrophy, affects epithelial renewal and reproduction. However, the regulatory mechanism of IEC G1-phase arrest is unknown. Our previous study verified that advanced oxidation protein products (AOPP) aberrantly accumulated in diseased intestinal tissues of patients with CD, induced intestinal cell death, and decreased the expression of calcium transport channels via the ROS-JNK/ERK signaling pathway, which suggested that AOPPs may play a role in CD. And recent studies have demonstrated that JNK/ERK are important pathways in regulating cell cycle. Our preliminary experiment further showed that AOPP can induce IEC G1-phase arrest and upregulate the expression of p27--negative regulator of the cell cycle. Therefore, we speculate that AOPP can induce IEC G1-phase arrest through activating the ROS-JNK/ERK-p27 signaling pathway. Following work: (1) explore the molecular mechanism underlying AOPP induce G1-phase arrest of IEC, including receptor pathway, ROS-JNK/ERK-p27 signal and the downstream cell cycle protein and cyclin-dependent kinase; (2) investigate the effect of blocking the cell signal pathways on AOPP-induced IEC G1-phase arrest, and the intervention effect of CD. Our study will clarify the role and mechanism of AOPP-induced IEC G1-phase arrest, thus providing a new view of the pathogenic mechanism of CD and a new way to prevention and treatment of CD.

小肠上皮细胞（IEC）G1期阻滞在克罗恩病（CD）中具有重要意义，可致小肠上皮萎缩、更新及修复受阻等病变，但IEC G1期阻滞的调控机制未明。我们前期研究证实晚期氧化蛋白产物（AOPP）在CD患者体内蓄积，并活化ROS-JNK/ERK诱导IEC凋亡、下调其钙通道蛋白表达，而研究表明JNK/ERK是调控细胞周期的重要通路。预实验显示AOPP可诱导IEC G1期阻滞，并上调细胞周期负调控因子p27的表达。因此，我们推测AOPP通过激活ROS-JNK/ERK-p27信号诱导IEC G1期阻滞。本项目拟研究①AOPP诱导IECs G1期阻滞的分子机制，包括受体途径，ROS-JNK/ERK-p27信号及下游的周期蛋白及激酶；②阻断AOPP生物学效应对IEC G1期阻滞和CD的干预作用。从分子-细胞-组织水平阐明AOPP诱导IEC G1期阻滞的作用及机制，为揭示CD发生发展的机制并为其防治提供新思路。

小肠上皮细胞(IEC) 周期阻滞最近被发现影响克罗恩病(CD)的发病。然而，调控这种细胞周期阻滞的机制仍不清楚。本项目研究了晚期氧化蛋白产物(AOPPs)在调节IEC周期阻滞中的作用。我们观察了CD患者血浆AOPPs水平和IEC细胞周期分布。用体外制备的AOPPs处理培养的永生化大鼠小肠上皮(IEC-6)细胞，观察细胞周期蛋白、细胞周期蛋白依赖性激酶(CDKs)以及其他调节分子的分子变化。采用正常C57BL/6小鼠急性AOPPs处理模型，观察AOPPs在体内的作用。我们证实了活动期CD患者血浆AOPPs水平升高，并与IEC G1期阻滞有关。此外，AOPPs还能在体内外有效地抑制细胞周期蛋白E和CDK2的表达，从而使上皮细胞对细胞周期阻滞产生敏感性。重要的是，我们发现AOPPs通过调节RAGE和CD36两种膜受体来诱导IEC G1期阻滞。c-Jun N-末端激酶(JNK)的磷酸化和p27kip1的表达在AOPPs处理的细胞中也随之增加，从而影响细胞周期的进展。我们的研究结果表明，AOPPs通过RAGE/CD36-JNK-p27kip1信号途径降低细胞周期蛋白E和CDK2的表达，诱导IEC G1期阻滞。因此，AOPPs作为一种潜在的治疗靶点，为防治CD提供了新方法。