Mouse models for LRRK2 Parkinson's disease.

Parkinson's disease (PD) is the second most common neurodegenerative disease. Mutations in Leucine-rich-repeat-kinase 2 (LRRK2), the causative gene for PARK8 type PD with autosomal dominant inheritance, are the most prevalent genetic causes of both familial and sporadic PD. Animal models are critical tools in the attempt to understand the mechanisms of LRRK2-mediated pathogenesis. We have generated human Bacterial Artificial Chromosome (BAC) mediated transgenic mouse models expressing mutant LRRK2 that robustly recapitulate the behavioral, neurochemical and pathological features of PD. These mice develop an age-dependent decrease in motor activity that is progressive and responds to treatment with levodopa. Pathologically, the most salient phenotype is early axonopathy of nigrostriatal dopaminergic neurons, accompanied by hyperphosphorylated tau. The mice also exhibit a consistent dopamine transmission deficit in both acute brain slices and live freely moving animals. Here we will discuss LRRK2 mouse models from several laboratories, their commonalities and differences, and offer scientific insights drawn from these studies.