Single-cell Herpes simplex virus type-1 infection of neurons using drop-based microfluidics reveals heterogeneous replication kinetics

Single-cell analyses of viral infections reveal heterogeneity that is not
detected by traditional population-level studies. This study applies
drop-based microfluidics to investigate the dynamics of HSV-1 infection of
neurons at the single-cell level. We used micron-scale Matrigel beads,
termed microgels, to culture individual murine Superior Cervical ganglia
(SCG) neurons or epithelial cells. Microgel-cultured cells are
subsequently encapsulated in individual media-in-oil droplets with a dual
fluorescent-reporter HSV-1, enabling real-time observation of viral gene
expression and replication. Infection within drops revealed that the
kinetics of initial viral gene expression and replication were dependent
on the inoculating dose. Notably, increasing inoculating doses led to
earlier onset of viral gene expression and more frequent productive viral
replication. These observations provide crucial insights into the
complexity of HSV-1 infection in neurons and emphasize the importance of
studying single-cell outcomes of viral infection. The innovative
techniques presented here for cell culture and infection in drops provide
a foundation for future virology and neurobiology investigations.