基于FGF21/SIRT1-p66shc线粒体通路研究鼠尾草酸抗肝脏缺血再灌注损伤的作用机制

Liver ischemia reperfusion (I/R) injury is of the high mortality rate. Mitochondrial oxidative damage is crucial during liver I/R injury. The fibroblast growth factor 21 (FGF21) is correlated with I/R injury and plays a vital role in mitochondrial function. However, the role of FGF21 in I/R injury remains unknown. Carnosic acid (CA), which is found in the extracts of rosemary leaves, has antioxidant properties. We firstly showed that CA protected rats against liver I/R injury. And we further found that the protection of CA was related with the inhibition of p66shc expression as a potential molecular mediator of hepatocellular mitochondrial oxidative stress and apoptosis by activating silent information regulator 1 (SIRT1). The preliminary experiments show that, CA pretreatment significantly increases FGF21 expression in liver I/R, with positive correlation to the expresson of SIRT1. By contrast, the knockout of FGF21 in vitro gives rise to a reduction of SIRT1, leading to the deterioration of mitochondrial injury and apoptosis. Therefore, it is concluded that CA regulates SIRT1/p66shc signaling pathway by upregulating FGF21 so as to be an important prevention strategy against liver I/R injury. In this study, a variety of advanced molecular biology methods will be used for confirming the vital role of FGF21 in protection against mitochondrial dysfunction and apoptosis in liver I/R, and revealed the molecular mechanism that CA regulates FGF21-mediated SIRT1/p66shc pathway after liver I/R. This study is conducive to the development and clinical application of rosemary extractmay, and may provide new mechanism and represent an attractive pharmacological target for arresting liver I/R injury.

肝脏缺血再灌注（I/R）损伤致死率极高，线粒体氧化损伤是肝脏I/R损伤的关键环节。FGF21参与线粒体功能调节且与组织I/R损伤密切相关，但具体机制不清。鼠尾草酸为迷迭香中抗氧化成分最丰富的提取物，我们已证实其通过SIRT1/p66shc通路减轻肝脏I/R氧化应激和凋亡损伤。近期发现：在肝脏I/R后，鼠尾草酸能明显上调FGF21的表达，与SIRT1表达呈正相关；在细胞缺氧复氧干扰FGF21后，SIRT1表达降低，线粒体损伤和细胞凋亡加重。本项目拟在前期工作基础上，应用多种分子生物学技术，从细胞和分子水平证实FGF21在肝脏I/R线粒体损伤和细胞凋亡中的作用以及揭示鼠尾草通过FGF21激活SIRT1-p66shc信号通路减轻肝脏I/R损伤的分子机制。本研究有助于迷迭香提取物的开发和临床应用，为防治肝脏I/R损伤提供科学依据和治疗靶点。

肝脏缺血再灌注（I/R）损伤致死率极高，线粒体氧化损伤是肝脏I/R损伤的关键环节。成纤维细胞生长因子21 (FGF21)是肝移植患者敏感的生物标志物之一，且FGF21可以增加线粒体抗氧化能力和线粒体呼吸能力，改善线粒体功能。但FGF21在肝脏I/R损伤中的具体机制尚不明确。鼠尾草酸为迷迭香中抗氧化成分最丰富的提取物，我们前期研究证实：在肝脏I/R后，鼠尾草酸能明显上调FGF21的表达，与SIRT1表达呈正相关；在细胞缺氧复氧干扰FGF21后，SIRT1表达降低，线粒体损伤和细胞凋亡加重。本项目在前期工作基础上，进一步系统、深入研究，应用多种先进的分子生物学技术，从细胞和分子水平探索FGF21在肝脏I/R对SIRT1的作用及调控机制，取得了一系列研究成果如下：解析了FGF21在肝脏I/R损伤中的表达变化规律、功能作用和分子机制；探讨了FGF21对SIRT1的具体调控作用以及该通路在肝脏I/R中线粒体损伤和细胞凋亡中的重要作用；证实了鼠尾草通过FGF21激活SIRT1信号通路减轻肝脏I/R损伤；发现了miR-99b-5p上调FGF21进而减轻肝脏I/R氧化损伤和凋亡。上述研究成果有助于迷迭香提取物的开发和临床应用，为防治肝脏I/R损伤提供新的科学依据和治疗靶点。