LRRK2 and early-onset autosomal dominant Alzheimer disease: Wild-type and LRRK2G2019S knock-in (KI) mice were injected with Alzheimer’s disease (AD)-derived tau and concurrently treated with control diet or LRRK2 kinase inhibitor MLi-2 in diet targeting the IC50 or IC90 of LRRK2 based on previous research [20].