Single Amino Acid Substitution in the Matrix Protein of Rabies Virus Is Associated with Neurovirulence in Mice

• Published in: Viruses Vol. 16; no. 5; p. 699
• Main Authors: Harada, Michiko, Matsuu, Aya, Kaku, Yoshihiro, Okutani, Akiko, Inoue, Yusuke, Posadas-Herrera, Guillermo, Inoue, Satoshi, Maeda, Ken
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.05.2024
• Subjects: Adaptation; adults; Amino Acid Substitution; Analysis; Animals; Bats; Body weight; body weight changes; Brain; Brain - pathology; Brain - virology; Care and treatment; Cell Line; Cell lines; chickens; Cloning; Diagnosis; Embryo fibroblasts; Fibroblasts; Genomes; Health aspects; Infections; Infectious diseases; Inoculation; Laboratory animals; M protein; Matrix protein; Mice; mouse neuroblastoma cell; Nervous system; Neuroblastoma; neurons; Neurons - pathology; Neurons - virology; Neurovirulence; Plasmids; Propagation; Proteins; Rabies; Rabies - virology; Rabies lyssavirus; rabies virus; Rabies virus - genetics; Rabies virus - pathogenicity; RNA polymerase; RNA polymerases; Scientific equipment and supplies industry; Variance analysis; viral growth; Viral Matrix Proteins - genetics; Viral Matrix Proteins - metabolism; Virulence; Virulence (Microbiology); Virus Replication; Viruses; United States; Japan; United States > US; Germany; mouse neuroblastoma cell; rabies virus; amino acid substitution; matrix protein
• DOI: 10.3390/v16050699
• ISSN: 1999-4915

Rabies is a fatal encephalitic infectious disease caused by the rabies virus (RABV). RABV is highly neurotropic and replicates in neuronal cell lines in vitro. The RABV fixed strain, HEP-Flury, was produced via passaging in primary chicken embryonic fibroblast cells. HEP-Flury showed rapid adaptation when propagated in mouse neuroblastoma (MNA) cells. In this study, we compared the growth of our previously constructed recombinant HEP (rHEP) strain—based on the sequence of the HEP (HEP-Flury) strain—with that of the original HEP strain. The original HEP strain exhibited higher titer than rHEP and a single substitution at position 80 in the matrix (M) protein M(D80N) after incubation in MNA cells, which was absent in rHEP. In vivo, intracerebral inoculation of the rHEP-M(D80N) strain with this substitution resulted in enhanced viral growth in the mouse brain and a significant loss of body weight in the adult mice. The number of viral antigen-positive cells in the brains of adult mice inoculated with the rHEP-M(D80N) strain was significantly higher than that with the rHEP strain at 5 days post-inoculation. Our findings demonstrate that a single amino acid substitution in the M protein M(D80N) is associated with neurovirulence in mice owing to adaptation to mouse neuronal cells.