背景:酒精相关性肝病(ALD)是肝脏相关发病率和死亡率的主要原因,但目前尚无预防ALD相关肝纤维化的治疗靶点和方法。过氧化物酶体增殖物激活受体(PPAR)α和δ在脂质代谢和肠屏障稳态中起关键作用,是ALD病理进展的主要原因。同时,Elafibranor(EFN),它是PPARα和PPARδ的双重激动剂,已达到治疗代谢功能障碍相关的脂肪变性肝病和原发性胆汁性胆管炎的III期临床试验。然而,EFN对ALD治疗的益处尚不清楚.
目的:评价EFN对ALD小鼠肝纤维化和肠屏障功能障碍的抑制作用。
方法:通过饲喂含有2.5%乙醇(EtOH)的Lieber-DeCarli液体饮食并腹膜内注射四氯化碳,在雌性C57BL/6J小鼠中诱导ALD相关的肝纤维化每周三次(1mL/kg),持续8周。在实验期间口服施用EFN(3和10mg/kg/天)。进行组织学和分子分析以评估EFN对脂肪性肝炎的影响,纤维化,和肠道屏障的完整性。通过基于细胞的测定来评估EFN对HepG2脂毒性和Caco-2屏障功能的影响。
结果:肝脂肪变性,凋亡,通过EFN治疗,ALD小鼠模型中的纤维化显著减轻。EFN促进EtOH刺激的HepG2细胞的脂解和β-氧化,并增强自噬和抗氧化能力,主要通过PPARα激活。此外,EFN抑制Kupffer细胞介导的炎症反应,肝暴露于脂多糖(LPS)和Toll样受体4(TLR4)/核因子κB(NF-κB)信号传导。EFN通过恢复紧密连接蛋白和自噬以及通过抑制细胞凋亡和促炎反应来改善肠道通透性。EtOH刺激的Caco-2细胞对肠屏障功能的保护作用主要由PPARδ活化介导。
结论:EFN通过抑制脂质积累和细胞凋亡减少ALD相关纤维化,增强肝细胞自噬和抗氧化能力,并通过恢复肠屏障功能抑制LPS/TLR4/NF-κB介导的炎症反应。
BACKGROUND: Alcohol-associated liver disease (ALD) is a leading cause of liver-related morbidity and mortality, but there are no therapeutic targets and modalities to prevent ALD-related liver fibrosis. Peroxisome proliferator activated receptor (PPAR) α and δ play a key role in lipid metabolism and intestinal barrier homeostasis, which are major contributors to the pathological progression of ALD. Meanwhile, elafibranor (EFN), which is a dual PPARα and PPARδ agonist, has reached a phase III clinical trial for the treatment of metabolic dysfunction-associated steatotic liver disease and primary biliary cholangitis. However, the benefits of EFN for ALD treatment is unknown.
OBJECTIVE: To evaluate the inhibitory effects of EFN on liver fibrosis and gut-intestinal barrier dysfunction in an ALD mouse model.
METHODS: ALD-related liver fibrosis was induced in female C57BL/6J mice by feeding a 2.5% ethanol (EtOH)-containing Lieber-DeCarli liquid diet and intraperitoneally injecting carbon tetrachloride thrice weekly (1 mL/kg) for 8 weeks. EFN (3 and 10 mg/kg/day) was orally administered during the experimental period. Histological and molecular analyses were performed to assess the effect of EFN on steatohepatitis, fibrosis, and intestinal barrier integrity. The EFN effects on HepG2 lipotoxicity and Caco-2 barrier function were evaluated by cell-based assays.
RESULTS: The hepatic steatosis, apoptosis, and fibrosis in the ALD mice model were significantly attenuated by EFN treatment. EFN promoted lipolysis and β-oxidation and enhanced autophagic and antioxidant capacities in EtOH-stimulated HepG2 cells, primarily through PPARα activation. Moreover, EFN inhibited the Kupffer cell-mediated inflammatory response, with blunted hepatic exposure to lipopolysaccharide (LPS) and toll like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) signaling. EFN improved intestinal hyperpermeability by restoring tight junction proteins and autophagy and by inhibiting apoptosis and proinflammatory responses. The protective effect on intestinal barrier function in the EtOH-stimulated Caco-2 cells was predominantly mediated by PPARδ activation.
CONCLUSIONS: EFN reduced ALD-related fibrosis by inhibiting lipid accumulation and apoptosis, enhancing hepatocyte autophagic and antioxidant capacities, and suppressing LPS/TLR4/NF-κB-mediated inflammatory responses by restoring intestinal barrier function.