Genetic contributions to influenza virus attenuation in the rat brain

Live Viral Vaccine Neurovirulence Screening: Current and Future Models

Live viral vaccines are one of the most successful methods for controlling viral infections but require strong evidence to indicate that they are properly attenuated. Screening for residual neurovirulence is an important aspect for live viral vaccines against potentially neurovirulent diseases. Approximately half of all emerging viral diseases have neurological effects, so testing of future vaccines will need to be rapid and accurate. The current method, the monkey neurovirulence test (MNVT), shows limited translatability for human diseases and does not account for different viral pathogenic mechanisms. This review discusses the MNVT and potential alternative models, including in vivo and in vitro methods. The advantages and disadvantages of these methods are discussed, and there are promising data indicating high levels of translatability. There is a need to investigate these models more thoroughly and to devise more accurate and rapid alternatives to the MNVT.

Anti-COVID-19 drug screening: Frontier concepts and core technologies

The outbreak of COVID-19 has recently evolved into a global pandemic. Up to July 2020, almost every country has confirmed COVID-19 cases reported worldwide. Many leading experts have predicted that the epidemic will persist for relatively a long period of time. Thus far, there have been no remedies proven effective against the disease. As the nation where COVID-19 broke out first, China has adopted a combination of traditional Chinese medicine and western medicine to fight against the disease, and has achieved significant clinical result. Up to now, the COVID-19 pandemic has been effectively controlled in China. However, the rest of the world (except for a limited number of countries and regions) is still in deep water. This paper thoroughly summarizes interdisciplinary notions and techniques, including disease model, biochip, network pharmacology, and molecular docking technology, etc., providing a reference for researchers in the screening of drugs for COVID-19 prevention and treatment. These methodologies may facilitate researchers to screen out more potential drugs for treating COVID-19 pneumonia and to tackle this global crisis.

The compensatory G88R change is essential in restoring the normal functions of influenza A/WSN/33 virus matrix protein 1 with a disrupted nuclear localization signal

G88R emerged as a compensatory mutation in matrix protein 1 (M1) of influenza virus A/WSN/33 when its nuclear localization signal (NLS) was disrupted by R101S and R105S substitutions. The resultant M1 triple mutant M(NLS-88R) regained replication efficiency in vitro while remaining attenuated in vivo with the potential of being a live vaccine candidate. To understand why G88R was favored by the virus as a compensatory change for the NLS loss and resultant replication deficiency, three more M1 triple mutants with an alternative G88K, G88V, or G88E change in addition to R101S and R105S substitutions in the NLS were generated. Unlike the other M1 triple mutants, M(NLS-88R) replicated more efficiently in vitro and in vivo. The G88R compensatory mutation not only restored normal functions of M1 in the presence of a disrupted NLS but also resulted in a strong association of M1 with viral ribonucleoprotein. Under a transmission electron microscope, only the M1 layer of the M(NLS-88R) virion exhibited discontinuous fingerprint-like patterns with average thicknesses close to that of wild-type A/WSN/33. Computational modeling suggested that the compensatory G88R change could reestablish the integrity of the M1 layer through new salt bridges between adjacent M1 subunits when the original interactions were interrupted by simultaneous R101S and R105S replacements in the NLS. Our results suggested that restoring the normal functions of M1 was crucial for efficient virus replication.