Study on anti-inflammatory properties of Zhankuic acid A the compound extracted from fruiting bodies of Taiwanofungus camphoratus

摘要

Taiwanofungus camphoratus is highly valued as a medicinal mushroom for cancer hypertension and inflammation in traditional medicine Zhankuic acid A (ZAA) is the major pharmacologically active compound of T camphoratus The mechanism of action of T camphoratus or ZAA has not been fully elucidated TLR4 a membrane receptor that functions in complex with its accessory protein myeloid differentiation factor-2 (MD-2) is a therapeutic target for bacterial infections We analyzed the structure of human TLR4/MD-2 complex with ZAA by X-score and HotLig modeling approaches Two antibodies against MD-2 were used to verify the MD-2/ZAA interaction The inflammation and survival of the mice pretreated with ZAA and injected with LPS were monitored The modeling structure shows that ZAA binds the MD-2 hydrophobic pocket exclusively via specific molecular recognition; the contact interface is dominated by hydrophobic interactions Binding of ZAA to MD-2 reduced antibody recognition to native MD-2 similar to the effect of lipopolysaccharide (LPS) binding Furthermore ZAA significantly ameliorated LPS-induced endotoxemia and Salmonella-induced diarrhea in mice Our results suggest that ZAA which can compete with LPS for binding to MD-2 as a TLR4/MD-2 antagonist may be a potential therapeutic agent for gram-negative bacterial infections Janus kinase 2 (JAK2) whose activation is involved in cytokine signaling plays critical roles in the development and biology of the hematopoietic system JAK2 has been implicated as a therapeutic target in inflammatory diseases The HotLig modeling approach was used to generate the binding model for ZAA with JAK2 showing that ZAA could bind to the ATP-binding pocket of JAK2 exclusively via the H-bond The interaction between ZAA and JAK2 was verified by antibody competition assay Binding of ZAA to JAK2 reduced antibody recognition of native JAK2 The expressions of phosphorylated JAK2 and STATs were analyzed by immunoblotting ZAA reduced the phosphorylation and downstream signaling of JAK2 and inhibited the interferon (IFN)-γ/signal transducer and activator of transcription (STAT) 1/ interferon regulatory factor (IRF)-1 pathway The protective effect of ZAA on liver injury was evaluated in mice by Con-A-induced acute hepatitis Pretreatment with ZAA also significantly ameliorated acute liver injury in mice Therefore ZAA can inhibit JAK2 phosphorylation and protect against liver injury during acute hepatitis in mice In this study we present data that ZAA exerts anti-inflammatory effects through the JAK2 signaling pathway Therefore ZAA may be a potential therapeutic agent for the treatment of inflammatory diseases

獎項日期	2014 7月 31
原文	English
監督員	Tian-Shung Wu (Supervisor)