TREM2 and Alzheimer disease: Neuroinflammation in App knock-in mice have previously been described to comprise both astrocytosis and microgliosis which was further confirmed here by increases in AD-associated ApoE and Trem2 and by activated neuroinflammatory pathways including TNF signaling, toll-like receptor signaling, cytokine signaling and activation of the complement system [14, 33, 62–64].