Life cycle process dependencies of positive-sense RNA viruses suggest strategies for inhibiting productive cellular infection

Abstract

Positive strand (+)RNA viruses are the most common and clinically important human pathogens. Their life cycle processes are broadly conserved across many virus families but they employ different life cycle strategies for their growth in the cell. Upon RNA genome release into the cytoplasm post cellular entry, viral translation generates structural and non-structural proteins that induce intracellular remodelling, forming membrane compartments that foster viral replication leading to virus particle formation. We present a generalized dynamical model for intracellular (+)ssRNA virus growth that accounts for these critical steps. Our model can capture experimental growth dynamics for several RNA viruses as well as parse the effect of viral mutations and host cell permissivity. We show that Poliovirus (PV) employs rapid replication and virus assembly whereas Japanese Encephalitis virus leverages its higher rate of translation and efficient host membrane reorganization for enhanced viral dynamics compared to Hepatitis C virus. Since the slow membrane reorganization represents a crucial bottleneck for replication, stochastic simulations demonstrate that an infection event, even with multiple viral genomes, can go to extinction if all seeding viral RNA degrade before establishing robust viral replication. We estimate this probability of productive cellular infection, termed ‘Cellular Infectivity (Φ)’ using stochastic simulations. Φ varies for a virus-host pair with initial virus seeding and life cycle perturbations like increase in cytoplasmic RNA degradation and delay in compartment formation can reduce infectivity. Extent of synergy among these parameters while seemingly diverse for viruses is defined by Φ. Therefore, our model suggests new avenues for inhibition of viral infections by targeting early life cycle bottlenecks.

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Sterile Inflammation Alters Neutrophil Kinetics in Mice

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