Disruption of Glial Ca2+ Oscillations at the Drosophila Blood-Brain Barrier Predisposes to Seizure-Like Behavior

Glia play key roles in regulating multiple aspects of neuronal development and function from invertebrates to humans. We recently found microdomain Ca2+ signaling in Drosophila cortex glia and astrocytes regulate extracellular K+ buffering and neurotransmitter uptake, respectively. Here we identify a role for ER store-operated Ca2+ entry (SOCE) in perineurial glia (PG), a distinct population that contributes to the blood-brain barrier (BBB). PG show a diverse range of Ca2+ oscillatory activity that varies based on their locale within the brain. Unlike cortex glia and astrocytes, PG Ca2+ oscillations do not require extracellular Ca2+ and are blocked by inhibition of SOCE or gap junctions. Disruption of these components triggers heat shock and mechanical-induced seizure-like episodes without effecting PG morphology or large molecule BBB permeability. These findings indicate SOCE-mediated Ca2+ oscillations in PG increase the susceptibility of seizure-like episodes in Drosophila, providing an additional link between glial Ca2+ signaling and neuronal activity.