Li X K, Fujino M, Sugioka A, Morita M, Okuyama T, Guo L, Funeshima N, Kimura H, Enosawa S, Amemiya H, Suzuki S
Department of Experimental Surgery and Bioengineering, National Children's Medical Research Center, Tokyo, Japan.
Transplantation. 2001 Feb 27;71(4):503-8. doi: 10.1097/00007890-200102270-00004.
Fulminant hepatitis in mice could be induced by gene-transfection of Fas ligand (FasL). However, the mechanisms of this event still remain controversial as to whether it is mediated by direct Fas/FasL interaction and/or neutrophil migration. To investigate the role of exogenous FasL-expression, we established a simple but clear mouse model on which we performed liver transplantation between Fas-mutant mice (MRL-lpr/lpr) and wild-type mice (MRL+/+).
The controls were nontransplanted wild-type (group 1) and MRL-lpr/lpr (group 2) mice. We obtained recipients with a Fas defect only in the liver (group 3; MRL-lpr/lpr liver graft in wild-type mice) and Fas-defected recipients with Fas-positive livers (group 4; wild-type graft in MRL-lpr/lpr). We successfully expressed FasL in the liver by cotransfection of two types of adenoviral vectors, AxCALNFasL and AxCANCre, with a Cre-loxP switching system.
FasL-expression in the livers in groups 3 and 4 resulted in animal death due to fulminant hepatitis within 48 hr after administration of the vectors. We obtained similar findings in group 1, whereas the mice in group 2 survived without any evidence of hepatitis. Immune staining revealed a marked infiltration of CD11b-positive cells in group 1 and group 3. Despite the number of apoptotic cells, a few infiltration of CD11b-positive cells were seen in group 4. We observed no remarkable findings in the FasL-expressed livers in group 2.
The results indicated that exogenous FasL-expression induces hepatocyte apoptosis both by direct interaction with Fas and by recruiting Fas-positive inflammatory cells. These findings are important for generating a new strategy to prevent hepatitis as well as for understanding the role of the Fas/FasL interaction in the pathophysiology of hepatitis.
通过基因转染Fas配体（FasL）可诱导小鼠暴发性肝炎。然而，关于该事件的机制，即其是否由直接的Fas/FasL相互作用和/或中性粒细胞迁移介导，仍存在争议。为了研究外源性FasL表达的作用，我们建立了一个简单而明确的小鼠模型，在该模型上我们在Fas突变小鼠（MRL-lpr/lpr）和野生型小鼠（MRL+/+）之间进行了肝移植。
对照组为未移植的野生型小鼠（第1组）和MRL-lpr/lpr小鼠（第2组）。我们获得了仅肝脏存在Fas缺陷的受体（第3组；野生型小鼠体内植入MRL-lpr/lpr肝脏）和肝脏Fas缺陷但肝脏为Fas阳性的受体（第4组；MRL-lpr/lpr小鼠体内植入野生型肝脏）。我们通过两种腺病毒载体AxCALNFasL和AxCANCre与Cre-loxP转换系统共转染，成功在肝脏中表达了FasL。
第3组和第4组肝脏中FasL的表达导致在给予载体后48小时内动物因暴发性肝炎死亡。我们在第1组中获得了类似的结果，而第2组的小鼠存活且没有任何肝炎迹象。免疫染色显示第1组和第3组中有明显的CD11b阳性细胞浸润。尽管存在凋亡细胞数量，但在第4组中可见少量CD11b阳性细胞浸润。我们在第2组中FasL表达的肝脏中未观察到明显异常。
结果表明，外源性FasL表达通过与Fas直接相互作用以及招募Fas阳性炎性细胞诱导肝细胞凋亡。这些发现对于制定预防肝炎的新策略以及理解Fas/FasL相互作用在肝炎病理生理学中的作用具有重要意义。
