Circadian rhythms and viral infections

A study suggests that the timing of a viral infection, in relation to the host’s circadian cycle, can influence disease progression. Disruption of an organism’s circadian rhythm can influence its immune response, but the effects of hosts’ circadian rhythms on the progression of viral diseases remain unclear. Akhilesh Reddy and colleagues infected mice as well as mouse fibroblasts with herpesvirus at different times during the day. Compared with mice infected at the onset of their active phase, corresponding to a period of darkness, mice exposed to the virus at the beginning of their resting period, corresponding to a period of light, exhibited 10-fold higher viral replication. Similarly, time of infection influenced viral replication in mouse fibroblasts, suggesting that the cellular circadian clock controls viral disease progression. Furthermore, the disruption of the key clock gene Bmal1 enhanced herpes infection in mice as well as mouse fibroblasts, and influenza A virus infection in mouse fibroblasts. Proteomic analyses suggested that intracellular protein trafficking, biosynthetic processes, protein synthesis, and chromatin assembly may contribute to the circadian regulation of viral infections. According to the authors, the findings suggest that circadian cycle disruptions can influence the severity of viral infections, and may represent a potential tool for modulating viral replication in hosts. - Read at PNAS.org

Article #16-01895: “Cell autonomous regulation of herpes and influenza virus infection by the circadian clock,” by Rachel S. Edgar et al.