LRRK2 G2019S Impairs Chaperone-Mediated Autophagy in Neurons (IN2-1.001)

OBJECTIVE: To explore whether leucine-rich repeat kinase 2 (LRRK2) G2019S mutation causes dysfunctional chaperone-mediated autophagy (CMA) in neuronal culture models and post-mortem Parkinson9s disease (PD) brain. BACKGROUND: LRRK2 G2019S mutation is the major genetic cause of PD, and most LRRK2 G2019S PD cases exhibit α-synuclein containing Lewy body pathology. Since LRRK2 has the consensus sequences required for CMA degradation, we investigated the relationship between LRRK2 G2019S and CMA, the pathway for α-synuclein lysosomal degradation, in neurons. DESIGN/METHODS: We used a novel CMA reporter in dopaminergic neuronal cultures derived from LRRK2 G2019S and wild type (wt) mice to study CMA activity. We also investigated whether LRRK2 G2019S affected α-synuclein association with a lysosomal marker, lysosomal membrane associated protein type 2 (LAMP2) in neuronal cultures. Finally, we studied the levels of the key CMA component, lysosomal membrane associated protein type 2A (LAMP-2A), in post-mortem brain from two LRRK2 G2019S PD cases and two age-matched controls. RESULTS: We found that decreased CMA activity in neurons from LRRK2 G2019S mice than wt mice as reflected by the number of lysosomes associated with CMA reporter per cell (2.73 ± 0.66 in LRRK2 G2019S vs.11.73 ±1.43 in wt, p CONCLUSIONS: LRRK2 G2019S can interfere with CMA in neurons, which appears to cause α-synuclein accumulation. This might underlie the α-synuclein pathology in LRRK2 G2019S PD cases. Supported by: American Academy of Neurology Research Fellowship, Parkinson9s Disease Foundation. Disclosure: Dr. Kuo has nothing to disclose. Dr. Orenstein has nothing to disclose. Dr. Koga has nothing to disclose. Dr. Tang has nothing to disclose. Dr. Kanter has nothing to disclose. Dr. Alcalay has received research support from The NIH K02 NS080915, Brookdale Foundation: The Brookdale Foundation Leadership in Aging Fellowship, Parkinson9s Disease Foudnation, Smart Foundation, Michael J Fox Foundation. Dr. Cuervo has nothing to disclose. Dr. Sulzer has nothing to disclose.