AUTHOR=Li Chunfu , Wang Yongzhi , Liu Huiting , Zhang Xinghua , Baolige Dalai , Zhao Shihua , Hu Wei , Yang Yang 

TITLE=Change in the Single Amino Acid Site 83 in Rabies Virus Glycoprotein Enhances the BBB Permeability and Reduces Viral Pathogenicity

JOURNAL=Frontiers in Cell and Developmental Biology

VOLUME=Volume 8 - 2020

YEAR=2021

URL=https://www.frontiersin.org/journals/cell-and-developmental-biology/articles/10.3389/fcell.2020.632957

DOI=10.3389/fcell.2020.632957

ISSN=2296-634X

ABSTRACT=Lab attenuated rabies virus (RABV) possesses highly cellular adaptation and lower pathogenicity than wild type RABV. However, the molecular factors that lead to regulate the cellular adaptation and pathogenicity remain obscure. In this work, we isolated a wild-type RABV (CNIM1701) from rapid bovine in northern of China. The original CNIM1701 was mortal to adult mice and restricted replication in cell cultures. After 20 serial passage in the sucking mice brain, the virus was renamed as CNIM1701-P20 which was safe to adult mice and replicated well in cell cultures. In addition, sequence comparison analysis of the original CNIM1701 and CNIM1701-P20 identified 2 amino acid substitutions on G protein (Lys83→Arg83 and Pro367→Ser 367) related to pathogenesis and cellular adaptation. Using site-directed mutagenesis to exchange Lys83 with Arg83 and Pro367 with Ser 367 in the G protein of RABV SAD strain, the pathogenicity of rSAD-K83R was significantly decreased. Our data indicated that the decreased the pathogenicity of rSAD-K83R is due to increase the expression and incorporation G of RABV, which also induced a higher level of apoptosis in infected cells. Furthermore, the K83 mutation induced high expression of MMP-2 and MMP-9 on DCs and promoted Blood-Brain Barrier (BBB) permeability. These results demonstrate that the pathogenesis of RABV is partially dependent on the G expression and BBB permeability, which may be helpful in designing and developing highly safe live-RABV vaccines.