腺相關病毒攜帶Interleukin-22基因在原發性膽道硬化症之治療效果

Abstract

原發性膽道硬化症 (Primary biliary cirrhosis，PBC) 是一種慢性肝臟自體免疫疾病，它是由於免疫系統攻擊肝內小膽管造成非化膿性發炎、損壞及膽汁鬱積的情況，最終導致肝纖維化及肝硬化發生，臨床上有三分之一病人對於唯一核准之臨床用藥-ursodeoxycholic acid (UDCA) 不具感受性，顯示目前對於發展新型藥物之迫切與需要。IL-22屬於IL-10 cytokine family，它是一個對抗外來病原菌感染、促進組織修復及維持組織完整之細胞激素，在免疫反應調控上也扮演重要角色。在許多發炎反應中，IL-22具有抑制發炎及修復之效果，而在多種肝臟發炎及自體免疫疾病模式中，IL-22更被指出具有保護作用。先前研究指出AAV (Adeno-associated virus) 本身不具致病性，且AAV vector能有效感染不同細胞並且長期表現所攜帶之目標基因，目前在動物模式及臨床試驗中以AAV vector作為基因治療載體皆顯示不錯之成效。本實驗室先前研究將小鼠誘發PBC前以尾靜脈注射方式給予3 x 107 TU AAV-mIL-22，發現可有效減緩門脈浸潤及纖維化現象，顯示IL-22在PBC疾病中具有保護性之免疫調節作用。本研究探討以AAV攜帶IL-22基因在PBC疾病中之治療效果。我們使用2-OA-OVA搭配α-GalCer致敏小鼠產生PBC症狀，並於致敏後第三周將9 x 107 TU AAV-mIL-22以尾靜脈注射方式給予PBC小鼠，並於第十周犧牲觀察發炎及纖維化相關之肝臟病理、mRNA、及單核球變化。實驗結果顯示給予9 x 107 TU AAV-mIL-22可降低浸潤到肝臟單核球數目，並減少發炎相關細胞激素 (IFN-γ及TNF-α)、chemokines (CXCL10及CXCL16)、及纖維化相關基因 (collagen I及collagen III) 之mRNA表現，以減緩門脈區發炎及纖維化現象。因此AAV-mIL-22可有效減緩PBC疾病以達治療之效果，未來期許可作為治療PBC疾病之臨床用藥。

Primary biliary cirrhosis (PBC) is an autoimmune disease, characterized by immune-mediated destruction of small-size intrahepatic bile ducts, leading to non-suppurative cholangitis, liver fibrosis and cirrhosis. There are one-third of PBC patients showing inadequate biochemical response to single-licensed therapy- ursodeoxycholic acid (UDCA). Awareness of unmet need has demonstrated the urgency and demand of development of new therapeutic treatment to PBC disease. IL-22, a member of the IL-10 cytokine family, is associated with antimicrobial defense, tissue repair and integrity as well as immune regulation. IL-22 is important with anti-inflammatory response and tissue repair in many inflammatory diseases. IL-22 serves as a protective role in a variety of liver injury and autoimmune diseases. Adeno-associated virus (AAV) vectors can efficiently infect a variety of cells and maintain long-term gene expression and has not been associated with pathology. AAV-mediated gene therapy has shown success in many animal disease models and clinical trials. Our previous study showed that mice injected with 3 x 107 TU of AAV-mIL-22 before initiation of PBC had decreased infiltration of immune cells and fibrosis in liver portal triads of 2-OA-OVA/α-GalCer immunized mice, suggesting that IL-22 played a protective role in PBC disease. In this study, we investigated the therapeutic effects of AAV-mIL-22 in PBC disease. 9 x 107 TU AAV-mIL-22 were injected to 2-OA-OVA/α-GalCer immunized mice at week 3 post immunization and PBC features including liver pathology, inflammatory cytokines and fibrosis-related proteins, liver mononuclear cells infiltration were examined at week 10. Our results demonstrated that administration of 9 x 107 TU AAV-mIL-22 efficiently reduced liver mononuclear cells infiltration and mRNA expressions of inflammatory-related cytokines (IFN-γ and TNF-α), chemokines (CXCL10 and CXCL16) and fibrosis-related proteins (collagen I and collagen III). In conclusion, AAV-mIL-22 treatment could efficiently reduce PBC disease and could be a promising treatment to PBC in the future.