Alzheimer's Disease (AD) is the primary cause of dementia, characterized by irreversible neurodegeneration resulting in memory loss and cognitive decline. Growing evidence suggests that neuroinflammation plays a pivotal role in AD, with extracellular ATP (eATP) as one of the key players in this process. Our project aims at investigating whether eATP influences microglia activation, AD-associated neuroinflammation and neuronal Ca2+ excitability in an AD mouse model (B6.152H) expressing human PS2-N141I and APP Swedish mutations. We conducted experiments at various disease stages: pre- and post-Ab plaque deposition, at 2 and 6 months of age, and during overt cognitive deficits at 9 months.Our morphological analyses demonstrated early microglia activation before Ab plaque deposition, accompanied by an increased expression of the inflammasome NLRP3, as well as elevated levels of the inflammatory cytokines IL-1β, IL-6 and TNF-α. To investigate whether this early neuroinflammation is accompanied by an increase of eATP, we are optimizing in vivo brain eATP measurements by using a specific genetically encoded ATP probe.Additionally, we are interested in determining whether microglial activation is associated with neuronal hyperexcitability, a feature that emerges at the initial stages of AD. We are employing two-photon microscopy and electrical stimulation to study both spontaneous and evoked neuronal Ca2+ activity, by means of GCaMP6f Ca2+ indicator, in somatosensory cortex (SSCx) brain slices of 2-month-old female WT and AD mice.Different experimental strategies will be employed to modulate brain eATP concentration and correlate it with neuroinflammation and neuronal excitability, defining new potential therapeutic targets to delay/halt AD neurodegeneration.