Lin, Y.-E.; Jaimon, E.; Tonelli, F.; Alessi, D. R.; Pfeffer, S. R.

Parkinsons disease-associated, activating mutations in LRRK2 kinase block primary cilia formation in cell culture and in specific cell types in the brain. In the striatum that is important for movement control, about half of astrocytes and cholinergic interneurons, but not the predominant medium spiny neurons, lose their primary cilia. Here we show that Parvalbumin interneurons that are inhibitory regulators of movement also lose primary cilia. Without cilia, these neurons are not able to respond to Sonic hedgehog signals that normally induce the expression of Patched protein, and their numbers decrease. In addition, glial cell line-derived neurotrophic factor-related Neurturin expression is significantly decreased. These experiments highlight the importance of Parvalbumin neurons in cilia-dependent, neuroprotective pathways and show that LRRK2 activation decreases Neurturin production, resulting in less neuroprotection for dopamine neurons.