对乙酰氨基酚肝损伤中诱导型血红素氧化酶/一氧化碳介导的抗炎抗氧化保护机制在肝细胞再生中的作用

Heme oxygenase-1 (HO-1)/carbon monoxide (CO), a crucial anti-inflammatory, antioxidative molecule, plays important roles in inflammatory liver diseases including acetaminophen (APAP)-evoked acute liver injury, however the molecular mechanisms involved are not fully elucidated. In the present study, we hypothesize that HO-1 upregulated during APAP-evoked acute liver injury play anti-inflammatory and antioxidative roles through generating CO, which further promotes regeneration of hepatocytes through activating PI3K/Akt/mTOR signaling via M2 macrophages/anti-inflammatory cytokines and/or HGF medicated pathway. To explore the protective mechanisms of HO-1/CO during APAP-evoked acute liver injury, the influence of HO-1/CO expression as well as HO-1 inducer/inhibitor or CO donor on hepatocyte death and regeneration will be examined. Furthermore, the effect of HO-1/CO on M2 macrophages activation, anti-inflammatory cytokines, HGF levels, as well as the possible antagonistic effect of PI3K inhibitor, Akt1 knockout and mTOR inhibitor against HO-/CO will be investigated, to clarify the role of M2 macrophages-antiinlfammatory cytokines/HGF mediated PI3K-Akt-mTOR signaling in hepatocyte regenaration promoted by HO-1/CO. This study will shed light on the molecule mechanisms of the cytoprotective role of HO-1/CO in APAP-evoked acute liver injury, and provide theoretical support for developing effective therapeutic strategy.

经典抗炎抗氧化分子诱导型血红素氧化酶/一氧化碳（HO-1/CO）在对乙酰氨基酚（APAP）肝损伤中的保护作用及其分子机制尚不清楚。课题组假设：APAP急性肝损伤过程中氧化应激诱导HO-1产生CO发挥抗炎抗氧化作用；同时经PI3K/Akt/mTOR信号促进肝细胞再生。本课题拟通过观察HO-1/CO的表达变化、HO-1诱导剂/抑制剂或CO供体对APAP急性肝损伤的影响，以阐明HO-1/CO在APAP急性肝损伤中抗炎抗氧化保护作用；通过观察HO-1/CO对M2巨噬细胞活化、HGF产生的影响，及PI3K抑制剂、Akt1基因敲除和mTOR抑制剂对HO-1/CO促进肝细胞再生的拮抗效应，以阐明HGF/抗炎细胞因子介导的PI3K-Akt-mTOR信号在HO-1/CO调控APAP急性肝损伤肝细胞再生过程中的作用。本课题将阐明HO-1/CO对APAP急性肝损伤的保护分子机理并为研发有效治疗方法提供理论依据。

诱导型血红素氧化酶（HO-1）及其代谢产物一氧化碳（CO）是人体内一种重要的抗氧化、抗炎症、细胞保护分子，然而其在对乙酰氨基酚（APAP）肝损伤中的保护作用及其分子机制尚不清楚。课题组假设：APAP急性肝损伤过程中氧化应激诱导HO-1产生CO发挥抗炎抗氧化作用；同时经PI3K/Akt/mTOR信号促进肝细胞再生。本课题通过系列研究发现，APAP 急性肝损伤过程中氧化应激水平与HO-1/CO的表达正相关、HO-1诱导剂或CO供体减轻APAP 引起的肝组织氧化损伤，抑制促炎因子释放。课题组观察了HO-1 诱导剂、抑制剂及外源性CO 供体对HGF 水平的影响，结果显示HO-1/CO 升高HGF 水平，促进肝细胞增殖，与APAP 急性肝损伤肝细胞再生相关。课题组检测了APAP 急性肝损伤的不同阶段M2 巨噬细胞在肝脏中的分布及其与肝细胞再生的相关性，发现现HO-1/CO 促进巨噬细胞向M2 极化，继而加快增殖速度，促进APAP 急性肝损伤肝细胞再生。研究还发现HO-1诱导剂或CO供体升高抗炎细胞因子IL-10 水平，加快APAP 急性肝损伤肝细胞再生速度。课题组也研究了PI3K/Akt/mTOR 信号在APAP 急性肝损伤肝细胞再生中的作用。结果发现，Akt 特异抑制剂明显抑制了APAP 急性肝损伤过程肝细胞再生。综上所述，本课题研究结果显示，APAP 急性肝损伤过程中氧化应激诱导HO-1 表达，通过产生CO 发挥抗炎抗氧化组织保护作用；同时，CO 通过诱导HGF 释放和激活M2型巨噬细胞释放抗炎细胞因子，启动肝细胞PI3K/Akt信号促进肝细胞再生。本课题清楚地表明了HO-1/CO对APAP急性肝损伤的保护作用并阐明其分子机理，这些结果将为研发有效的针对APAP 急性肝损伤的治疗方法提供理论依据。