MAPKs-线粒体crosstalk调控自噬在砷致肝损伤中的作用和竹荪多糖的干预研究

Arsenic pollution seriously endangers human health, the liver damage caused by it has become one of the prominent problems of endemic arsenic. Mitochondria, as an important site of cellular ATP production, are also involved in many life activities such as fatty acid oxidation and cell death initiation. Changes in the structure and function of mitochondria become hot topics of current research and are closely related to autophagy. MAPKs is one of the important pathways in eukaryotic signal transduction network. It participates in a series of reactions such as cell growth, differentiation, and apoptosis, which are common pathways and focal points for extracellular signal-induced cellular physiology. The effect of autophagy regulated by MAPKs and mitochondrial crosstalk in arsenic-induced liver injury has not been reported so far. Our previous study confirmed that improve the effect of Dictyophora polysaccharides on arsenic-induced liver injury related to the regulation of MAPKs, energy metabolism and apoptosis. In this study, liver cells and rats were selected as research object to establish cells and animal models of arsenic poisoning. MAPKs, mitochondrial and autophagy function inhibitors and Dictyophora polysaccharide were used to analyze the signal regulation between MAPKs and mitochondria and the effect of autophagy in arsenic-induced liver injury. To investigate the effects of Dictyophora polysaccharide on MAPKs and mitochondrial signal crosstalk and autophagy, and to provide a new theoretical and experimental basis for the prevention and treatment of liver damage caused by endemic arsenic and drug development.

砷污染严重危害人类健康，其所致的肝损伤已成为地方性砷中毒突出问题之一。线粒体作为能量产生的重要场所同时参与脂肪酸氧化和启动细胞死亡等多种生命活动，其结构和功能的变化成为当前研究热点。线粒体的结构和功能变化与自噬有关。MAPKs是真核生物信号传递网络中的重要途径之一，参与细胞生长、分化和凋亡等系列反应，是细胞外信号引起细胞生理反应的共同途径和汇聚点。MAPKs与线粒体crosstalk调控的自噬在砷致肝损伤的作用迄今未见报道。前期研究证实竹荪多糖对砷致肝损伤的改善作用与MAPKs、能量代谢和凋亡等有关。本项目以肝细胞和大鼠为研究对象，建立砷中毒细胞和动物模型，采用MAPKs、线粒体、自噬功能抑制剂和竹荪多糖进行干预，分析MAPKs与线粒体间的调控以及调控的自噬在砷致肝损伤中的作用并探讨竹荪多糖和保护作用，为地方性砷中毒肝损伤与的防治和药物开发提供新的理论和实验依据。

砷暴露所致的肝损伤是地方性砷中毒的突出问题之一，但机制未明。本项目在前期研究基础上，从动物、细胞两个层次侧重探讨了丝裂原活化蛋白激酶（Mitogen-activated protein kinase，MAPKs）与线粒体自噬crosstalk在砷致肝损伤中的作用及机制；同时，采用竹荪多糖（Dictyophora，DIP）进行了针对性干预研究。经过四年的项目实施，获得了一系列研究成果：① 从细胞层面初步观察和验证线粒体自噬在砷致肝细胞损伤中的关键作用。发现亚砷酸钠可活化L-02细胞PINK1/Parkin信号通路诱导线粒体自噬；环孢菌素A可抑制亚砷酸钠诱导的L-02细胞线粒体自噬；活性氧参与了亚砷酸钠诱导的L-02细胞线粒体自噬。② 从从细胞层面探索了MAPKs与线粒体自噬crosstalk在砷致肝细胞损伤中的作用机制及DIP的潜在应用价值。发现PD98059可通过抑制亚砷酸钠诱导的ERK信号通路的活化进而减轻L-02细胞的线粒体自噬；SP600125可通过抑制亚砷酸钠诱导的JNK信号通路的活化进而减轻L-02细胞的线粒体自噬；SB203580对亚砷酸钠诱导的L-02细胞线粒体自噬影响甚微；DIP可通过抑制亚砷酸钠诱导的ROS生成进而减轻L-02细胞的线粒体自噬。③ 从动物层面佐证了MAPKs与线粒体自噬crosstalk参与了砷所致的大鼠肝损伤。发现MAPK抑制剂可减轻亚砷酸钠诱导的大鼠肝损伤；MAPK抑制剂可通过抑制TGF-β1/SMAD信号通路的活化减轻亚砷酸钠诱导的大鼠肝损伤。本项目的系列研究较系统阐释了砷暴露所致肝损伤的发病机制，为新时期地方性砷中毒肝损伤可能干预靶点的选择和优化新的干预策略提供实验依据。