AQP4 and Parkinson disease: In addition, Sun et al. [147] demonstrated that AQP4 modulates astrocyte-to-microglia communication in neuroinflammation; AQP4 knockout mice exhibited gliosis (astrocytosis and microgliosis) in PD models produced by chronic MPTP injections, accompanied by an increase in the production of IL-1β and TNF-α in the midbrain.