LAUSR

Leucine-rich repeat kinase 2 (Lrrk2) has been implicated in the pathophysiology of Parkinson’s disease. Lrrk2 is expressed in diverse cells including neurons and dendritic cells (DCs). In DCs Lrrk2 was shown to up-regulate Na+/Ca2+-exchanger activity. The elimination of Ca2+ by Na+/Ca2+ -exchangers requires maintenance of the Na+ gradient by the Na+/K+ -ATPase. The present study thus explored whether Lrrk2 impacts on Na+/K+ -ATPase expression and function. To this end DCs were isolated from gene-targeted mice lacking Lrrk2 (Lrrk2−/−) and their wild-type littermates (Lrrk2+/+). Na+/K+ -ATPase activity was estimated from K+ induced, ouabain sensitive, current determined by whole cell patch clamp. Na+/K+ -ATPase α1 subunit transcript and protein levels were determined by RT-qPCR and flow cytometry. As a result, the K+ induced current was significantly smaller in Lrrk2−/− than in Lrrk2+/+ DCs and was completely abolished by ouabain (100 μM) in both genotypes. The K+ induced, ouabain sensitive, current in Lrrk2+/+ DCs was significantly blunted by Lrrk2 inhibitor GSK2578215A (1 μM, 24 hours). The Na+/K+ -ATPase α1 subunit transcript and protein levels were significantly lower in Lrrk2−/− than in Lrrk2+/+ DCs and significantly decreased by Lrrk2 inhibitor GSK2578215A (1 μM, 24 hours). In conclusion, Lrrk2 is a powerful regulator of Na+/K+ -ATPase expression and activity in dendritic cells.