The role of keratins in the liver

角蛋白（Keratins，K）是一个细胞保护蛋白家族，其突变可导致多种人类疾病的发生。在肝脏中，成年肝细胞仅产生K8/K18，而导管细胞和肝祖细胞（HPC）也表达K7/K19。K7/K19是由导管细胞和HPC组成的导管反应（DR）的最确定的标志物，代表了肝脏对损伤的基本再生反应。在上一个资助期，我们分析了肝损伤过程中角蛋白的变化，并研究了遗传性角蛋白变体对人类肝脏疾病发展的影响。我们还鉴定了K23作为一种新的DR标记物，并证明K19的缺失可减弱DR并促进胆汁淤积性肝损伤的发展。这些发现构成了当前更新提案的基本原理，该提案将系统地分析K7/K19在DR以及DR相关肝癌中的作用。为此，我们产生了K7/K19双敲除动物，并将它们与建立的鼠DR和肝癌模型（Mdr 2-科斯）杂交。动物的表型表征将通过胆汁组成和角蛋白结构分析进行补充。用分离的原代细胞连同单个角蛋白的敲低/转染的实验将使得能够对K7/K19在DR以及肿瘤形成中的作用进行详细的功能评估。拟议的研究将产生新的见解DR以及角蛋白在再生和肿瘤形成的重要性，是新兴的主题。

Keratins (K) constitute a large family of cytoprotective proteins and keratin mutations predispose to development of multiple human diseases. In the liver, adult hepatocytes produce K8/K18 only, while ductal cells and hepatic progenitor cells (HPCs) also express K7/K19. K7/K19 are the most established markers of ductular reaction (DR) that consists of ductal cells and HPCs and represents the basic regenerative response of the liver to injury.In the previous funding period, we analyzed the alteration of keratins during hepatic injury and studied the impact of inherited keratin variants on the development of human liver disease. We also identified K23 as a novel DR marker and demonstrated that loss of K19 attenuates DR and promotes the development of cholestatic liver injury. These findings constitute the rationale for the current renewal proposal that will systematically analyze the role of K7/K19 in the DR as well as in DR-related liver cancer. To that end, we generated K7/K19 double-knockout animals and crossbreed them with an established murine DR and liver cancer model (Mdr2-KOs). The phenotypic characterization of the animals will be complemented with analyses of bile composition and keratin architecture. Experiments with isolated primary cells together with knockdown/transfection of individual keratins will enable a detailed functional assessment of the role of K7/K19 in the DR as well as tumor formation. The proposed studies will yield novel insights into the DR as well as the importance of keratins in regeneration and tumor formation that are emerging topics.