Targeted delivery of PCBP2 siRNA for treating alcoholic liver fibrosis

描述(申请人提供)：肝纤维化/肝硬变是一个全球性的健康问题，也是世界上发病率和死亡率的主要原因之一。在西方发达国家，酒精滥用是导致肝纤维化/肝硬化的最常见原因之一，占肝硬化病例的50%以上。酒精性肝纤维化是一个涉及多种细胞因子的复杂过程，目前尚无针对肝纤维化的标准治疗方法。虽然肝纤维化是可逆的和可治疗的，但如果不治疗，它将发展到终末期，即肝硬变，这是不可逆转的和不可治疗的。因此，迫切需要有效的抗肝纤维化药物。我们的策略是逆转过度产生的I型胶原，I型胶原是在纤维化结束时形成的。这是酒精性肝纤维化有效治疗最关键的一步，因为无论采用何种治疗方法，肝纤维化中积聚的I型胶原都必须逆转。我们提出了siRNA来沉默PCBP2基因的表达，随后导致胶原1(I)mRNA的不稳定，最终逆转了积累的I型胶原。最近，我们发现酒精可上调肝星状细胞(HSCs)中PCBP2的表达。此外，我们还发现了一种siRNA，它可以沉默PCBP2基因，从而增加HSCs中胶原1(I)mRNA的衰减率。目前提案中概述的研究是专门设计通过使用靶向siRNA纳米复合体阻断PCBP2的表达来治疗实验动物的酒精性肝纤维化。应用的总体目标有两个：1)开发基于亲和素的纳米复合体，以克服PCBP2 siRNA的两个潜在障碍(稳定性差和缺乏靶向HSCs的能力)；2)使用各种体外和体内模型评估其治疗效果。我们的中心假设是，I型胶原堆积的逆转在酒精性肝纤维化的治疗中至关重要。我们建议的研究成果有望为其他肝病siRNA疗法的开发提供循证基础。

DESCRIPTION (provided by applicant): Liver fibrosis/cirrhosis is a global health problem and one of the leading causes of morbidity and mortality in the world. Alcohol abuse is one of the most common causes of liver fibrosis/cirrhosis in western developed countries, accounting for more than 50% of cirrhosis cases. Alcoholic liver fibrogenesis is a complicated process involving many cytokines, and unfortunately, there is no standard treatment for liver fibrosis till now. Whil liver fibrosis is reversible and treatable, if left untreated, it will develop to the end stage, lier cirrhosis, which is irreversible and untreatable. Therefore, effective antifibrotic medicines are needed urgently. Our strategy is to reverse the over-produced type I collagen which is formed at the end of fibrogenesis. It is the most critical step toward the effective therapy of alcoholic livr fibrosis because the accumulated type I collagen in fibrotic liver has to be reversed no matter what treatment is employed. We proposed siRNA to silence the PCBP2 gene expression, subsequently leading to destabilization of the collagen ¿1(I) mRNA and eventually the reversal of the accumulated type I collagen. Recently, we have proved that alcohol up-regulates the expression of PCBP2 in Hepatic Stellate Cells (HSCs). Moreover, we have identified a siRNA that can silence the PCBP2 gene and subsequently increase the decay rate of collagen ¿1(I) mRNA in HSCs. The research outlined in the current proposal has been designed specifically to treat alcoholic liver fibrosis in experimental animals via blocking the expression of PCBP2 using a targeted siRNA nanocomplex. The overall objectives in the application are two-fold: 1) to develop the avidin-based nanocomplex to overcome the two potential obstacles (poor stability and lack of target-ability to HSCs) of PCBP2 siRNA; 2) to evaluate its therapeutic effectiveness using various in vitro and in vivo models. Our central hypothesis is that the reversal of the accumulated type I collagen is critical in treatment of alcoholic liver fibrosis. Accomplishments o our proposed studies are expected to provide an evidence-based foundation for development of other siRNA therapeutics for liver diseases.