ABSTRACT
The angiopoietin-Tie2 binding and related signal transduction pathways are crucial for vascular angiogenesis, blood vessel integrity and maturation. In this study, we preformed a virtual screening of small molecules targeting to Tie2. The binding site was selected at the extracellular ligand binding region of Tie2, rather than its conventional endocellular ATP binding region. It was found that loperamide, a widely-used antidiarrhea drug, was among the top hits. The binding between loperamide and Tie2 was confirmed by surface plasmon resonance (SPR) assay. Loperamide competitively inhibited the binding of both angiopoietin1 and angiopoietin2. These results indicate that loperamide is an antagonist of angiopoietin1 and angiopoietin2.
Subject(s)
Angiopoietin-1/chemistry , Angiopoietin-2/chemistry , Antidiarrheals/chemistry , Loperamide/chemistry , Receptor, TIE-2/chemistry , Angiopoietin-1/antagonists & inhibitors , Angiopoietin-2/antagonists & inhibitors , Antidiarrheals/pharmacology , Binding, Competitive , Endothelial Cells/cytology , Endothelial Cells/metabolism , Endothelium, Vascular/cytology , Endothelium, Vascular/metabolism , High-Throughput Screening Assays , Humans , Ligands , Loperamide/pharmacology , Models, Molecular , Protein Binding , Receptor, TIE-2/antagonists & inhibitors , Recombinant Proteins/antagonists & inhibitors , Recombinant Proteins/chemistry , Signal Transduction , Surface Plasmon Resonance , Thermodynamics , User-Computer InterfaceABSTRACT
AIM: To explore the potential of electroporation (EP)-mediated hepatitis B virus (HBV) DNA vaccination for the treatment of chronic HBV infection. METHODS: BALB/c mice were vaccinated with HBV DNA vaccine encoding for the HBV preS(2)-S antigen, combined with or without EP. HBV surface antigen expression plasmid was administered into mice liver via a hydrodynamic injection to mimic HBV infection. The clearance of antigen in the serum and liver was detected by ELISA assay and immunohistochemical staining. The histopathology of the liver tissues was examined by HE staining and serum alanine aminotransferase assay. RESULTS: The immunogenicity of HBV DNA vaccine encoding for the HBV preS(2)- S antigen can be improved by EP-mediated vaccine delivery. The elicited immune responses can indeed reduce the expression of HBV surface antigen (HBsAg) in hepatocytes of the mouse model that was transfected to express HBsAg using the hydrodynamic injection method. The antigen clearance process did not cause significant toxicity to liver tissue, suggesting a non-cytolytic mechanism. CONCLUSION: The EP-aided DNA vaccination may have potential in mediating viral clearance in chronic hepatitis B patients.
