O006 Hepatitis A virus cellular receptor 1 (HAVCR1) influences the integrity of blood brain barrier (BBB) of cerebral endothelial cells

Abstract Introduction Hepatitis A virus cellular receptor 1 (HAVcR1) has been established to play an important role in tight junction (TJ) in cancer cells and in peripheral endothelial cells. Its role in blood brain barrier (BBB) of cerebral endothelium remains unknown. This study aimed to investigate the association and functionality of HAVcR1 in BBB. Methods HAVcR1 was knocked down by siRNA in human cerebral microvessel endothelial cell/D3 (hCMEC/D3) cell lines. Changes in tight junction (TJ) behaviour were assessed using electric cell impedance sensing (ECIS), transendothelial resistance (TER), and paracellular permeability (PCP). The expression of HAVcR1 and the binding partners of HAVcR1 protein was assessed using quantitative polymerase chain reaction (qPCR). Results The HAVcR1 gene transcript, highly expressed in hCMEC/D3 cells, was successfully knocked down from the cell by anti-HAVcR1 siRNA. HAVcR1 knockdown resulted in an increase in four TJ molecules and a decrease in eight TJ molecules as demonstrated by transcript analysis. HAVcR1 knockdown cells displayed lower electric resistance compared with wild type cells during initial attachment and spreading in hCMEC/D3 cells shown by ECIS. Similarly, TER in HAVcR1 knockdown cells were also reduced. Higher PCP fluorescence signals were detected in HAVcR1 knockdown cell lines compared with wild type. Conclusion HAVcR1 regulates paracellular leakage of cerebral endothelial cells and loss of HAVcR1 renders the cells with weaker tight junction by influencing TJ protein expression. HAVcR1 have a function as part of the regulatory apparatus for TJ in BBB.