Studies on mechanisms apoptosis and carcinogenesis of hepatocytes in hereditary liver disease and approaches for gene therapy for liver diseases

遗传性酪氨酸血症I型（HTI，富马酰乙酰乙酸水解酶缺乏症）的特征是严重的肝脏疾病和肝癌的高发病率。在这项研究中，我们研究了HT1的动物模型，以阐明这种疾病的致癌机制。在此之前，我们将缺陷型HPD基因导入白化病致死小鼠并成功挽救了其表型。在本研究中，我们使用尿黑酸诱导这些小鼠的肝细胞凋亡。(i)半胱天冬酶抑制剂的管理，防止肝细胞和肾小管上皮细胞的富马酰乙酰乙酸诱导的细胞凋亡。(ii)当细胞周期进行调查时，由富马酰乙酰乙酸损伤的细胞被阻滞在G2M。(iii)表达人延胡索酰乙酰乙酸水解酶的重组腺病毒对小鼠肝损伤的保护作用。此外，表达人延胡索酰乙酰乙酸水解酶的重组腺相关病毒拯救了小鼠。(iv)在模型小鼠中施用尿黑酸试图用于癌的发展。在组织学检查中，肝脏中出现异常细胞，但在本研究中未证实明显的癌。

Hereditary tyrosinemia type I (HTI, fumarylacetoacetate hydrolase deficiency) is characterized by severe liver disease and high incidence for liver carcinomas. In this study, we investigated animal model for HT1 to elucidate mechanisms for carcinogenesis in this disease. Previously, we introduced defective HPD gene into albino lethal mice and successively rescued the phenotype. In the present study, we administered homogentisic acid which lead to liver apoptosis in these mice.Following results are obtained.(i) Apoptosis induced by fumarylacetoacetate in hepatocytes and renal tubular epithelial cells were prevented by the administration of caspase inhibitors.(ii) When cell cycles were investigated, the cells injured by fumarylacetoacetate were arrested at G2M.(iii) Recombinant adenovirus expressing human fumarylacetoacetate hydrolase prevents the liver damage and rescue the mice. In addition, recombinant adeno associated virus expressing human fumarylacetoacetate hydrolase rescues the mice.(iv) Administration of homogentisic acid in the model mice was attempted for development of carcinoma. On histological examinatios, abnormal cells were appeared in the livers however, apparent carcinoma was not confirmed in the present study.