Translational Liver Research, Department of Medical Cell BioPhysics, Technical Medical Centre, Faculty of Science and Technology, University of Twente, the Netherlands; Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH University Hospital Aachen, Germany.
Department of Medical Cell BioPhysics, Technical Medical Centre, Faculty of Science and Technology, University of Twente, the Netherlands.
Biomed Pharmacother. 2023 Nov;167:115612. doi: 10.1016/j.biopha.2023.115612. Epub 2023 Oct 3.
Hepatocyte damage during liver injury instigates activation of macrophages and hepatic stellate cells (HSCs) resulting in liver inflammation and fibrosis respectively. Improving hepatocyte survival and proliferation thereby ameliorating inflammation and fibrosis represents a promising approach for the treatment of liver injury. In the liver, fibroblast growth factors (FGFs) play a crucial role in promoting hepatocyte proliferation and tissue regeneration. Among 22 FGFs, FGF7 induces hepatocyte survival and liver regeneration as shown previously in mouse models of cholestatic liver injury and partial hepatectomy. We hypothesized that FGF7 promotes hepatocyte survival and proliferation by interacting with FGFR2b, expressed on hepatocytes, and ameliorates liver injury (inflammation and early fibrogenesis) via paracrine mechanisms. To prove this hypothesis and to study the effect of FGF7 on hepatocytes and liver injury, we administered FGF7 exogenously to mice with acute carbon tetrachloride (CCl)-induced liver injury. We thereafter studied the underlying mechanisms and the effect of exogenous FGF7 on hepatocyte survival and proliferation, and the consequent paracrine effects on macrophage-induced inflammation, and HSCs activation in vitro and in vivo. We observed that the expression of FGF7 as well as FGFR2 is upregulated during acute liver injury. Co-immunostaining of FGF7 and collagen-I confirmed that FGF7 is expressed by HSCs and is possibly captured by the secreted ECM. Immunohistochemical analysis of liver sections showed increased hepatocyte proliferation upon exogenous FGF7 treatment as determined by Ki67 expression. Mechanistically, exogenous FGF7 improved hepatocyte survival (and increased drug detoxification) via AKT and ERK pathways while maintaining hepatocyte quiescence restricting hepatocarcinogenesis via P27 pathways. Flow cytometry analysis revealed that improved hepatocyte survival and proliferation leads to a decrease in infiltrated monocytes-derived macrophages, as a result of reduced CCL2 (and CXCL8) expression by hepatocytes. Moreover, conditioned medium studies showed reduced collagen-I secretion by HSCs (indicative of HSCs activation) upon treatment with FGF7-treated hepatocytes conditioned medium. Altogether, we show that exogenous administration of FGF7 induces hepatocyte survival and proliferation and leads to amelioration of inflammatory response and fibrosis in acute liver injury via paracrine mechanisms. Our study further demonstrates that FGF7, FGF7 derivatives, or nano-engineered FGF7 may benefit patients with hepatic dysfunction.
肝损伤时肝细胞损伤会激活巨噬细胞和肝星状细胞(HSCs),分别导致肝脏炎症和纤维化。改善肝细胞的存活和增殖,从而改善炎症和纤维化,是治疗肝损伤的一种有前途的方法。在肝脏中,成纤维细胞生长因子(FGFs)在促进肝细胞增殖和组织再生中起着至关重要的作用。在 22 种 FGF 中,FGF7 如先前在胆汁淤积性肝损伤和部分肝切除的小鼠模型中所示,可诱导肝细胞存活和肝再生。我们假设 FGF7 通过与表达在肝细胞上的 FGFR2b 相互作用来促进肝细胞的存活和增殖,并通过旁分泌机制改善肝损伤(炎症和早期纤维化)。为了证明这一假设并研究 FGF7 对肝细胞和肝损伤的影响,我们向急性四氯化碳(CCl)诱导的肝损伤小鼠体内外源性给予 FGF7。此后,我们研究了外源性 FGF7 对肝细胞存活和增殖的影响,以及对巨噬细胞诱导的炎症和 HSCs 激活的后续旁分泌效应。我们观察到 FGF7 和 FGFR2 的表达在急性肝损伤期间上调。FGF7 和胶原-I 的共免疫染色证实 FGF7 由 HSCs 表达,并可能被分泌的 ECM 捕获。肝组织切片的免疫组织化学分析显示,外源性 FGF7 处理后 Ki67 表达增加,提示肝细胞增殖增加。从机制上讲,外源性 FGF7 通过 AKT 和 ERK 通路改善肝细胞存活(并增加药物解毒),同时通过 P27 通路维持肝细胞静止,限制肝癌发生。流式细胞术分析显示,由于肝细胞表达的 CCL2(和 CXCL8)减少,改善的肝细胞存活和增殖导致浸润的单核细胞衍生的巨噬细胞减少。此外,条件培养基研究显示,用 FGF7 处理的肝细胞条件培养基处理后,HSCs 的胶原-I 分泌减少(提示 HSCs 激活)。总之,我们表明,外源性给予 FGF7 可通过旁分泌机制诱导肝细胞存活和增殖,并改善急性肝损伤中的炎症反应和纤维化。我们的研究进一步表明,FGF7、FGF7 衍生物或纳米工程 FGF7 可能使肝功能障碍患者受益。