Vacuolar ATPase阻斷劑Diphyllin抑制貓傳染性腹膜炎病毒之效果

Abstract

中文摘要 貓傳染性腹膜炎是由貓冠狀病毒變異株所引起，於多貓的環境易發高度的盛行率以及顯著的死亡率，目前並無良好的預防及治療方式。Diphyllin為一具有阻斷宿主Vacuolar ATPase活性的化合物，已知能藉由抑制內質體酸化而干擾流感病毒與登革病毒在細胞內的感染。本研究的目的為探討diphyllin對於貓傳染性腹膜炎病毒之抗病毒效果及其作用機制，選用的病毒株為第二型的貓傳染性腹膜炎病毒NTU156。本篇論文之研究結果顯示，diphyllin能有效抑制Fcwf-4細胞的內質體酸化，並抑制病毒在細胞內的複製，具有劑量依賴效應。藥物作用時間點試驗則顯示diphyllin在病毒入侵宿主細胞之前給予之效果為最佳。另外，併用抗病毒藥物Galanthus nivalis agglutinin能夠得到更好的協同效果。而在抗體依賴增強作用的細胞感染模式之下，diphyllin仍能有效降低病毒在Fcwf-4細胞與U937細胞中的複製。與單純的藥物相比，使用奈米載體遞送之diphyllin表現出顯著較低的細胞毒性，以及較佳的病毒抑制效應。總結以上之研究結果，diphyllin對於貓傳染性腹膜炎病毒具有良好之抗病毒效果，有潛力發展為臨床使用之抗病毒藥物。 關鍵字：貓傳染性腹膜炎病毒，Diphyllin，Vacuolar ATPase 阻斷劑，抗體依賴增強作用，奈米粒子。

Abstract Feline infectious peritonitis (FIP), caused by a mutated feline coronavirus, is one of the most serious and fatal viral diseases in cats. So far, it remains incurable, and there is no effective vaccine commercially available. The compound diphyllin, a novel vacuolar ATPase blocker, has been shown to inhibit the intracellular endosomal acidification, thus interfering the infection of influenza virus and dengue virus. This study aims to investigate the antiviral activity of diphyllin against the type II feline infectious peritonitis virus (FIPV) strain NTU156. The results show that diphyllin dose-dependently inhibited endosomal acidification in Fcwf-4 cells. Treatment with diphyllin altered the cellular susceptibility to FIPV and inhibited the downstream virus replication. Furthermore, combinatorial treatment of the host-targeting diphyllin with pathogen-targeting Galanthus nivalis agglutinin demonstrated enhanced cell protection. In the in vitro model of antibody-dependent enhancement of FIPV infection, diphyllin also showed a significant antiviral activity against FIPV in Fcwf-4 cells and U937 cells. In addition, nanoparticulate diphyllin further demonstrated a decreased cytotoxicity and improved inhibitory effect against FIPV. These results collectively suggest that diphyllin possesses therapeutic potential for the treatment of FIP. Keywords: Feline infectious peritonitis virus, Diphyllin, Vacuolar ATPase inhibitor, Antibody-dependent enhancement, Nanoparticles