LRRK2-IN-1 is an effective and selective LRRK2 inhibitor.

In HEK 293 cells stably expressing GFP-LRRK2[G2019S], LRRK2-IN-1 alters the cytoplasmic localization of LRRK2. In human-derived neuroblastoma SHSY5Y cells and mouse Swiss 3T3 cells, LRRK2-IN-1 induces a similar dose-dependent Ser910 and Ser935 dephosphorylation and loss of 14-3-3 binding to endogenous LRRK2. [1] In transgenic C. elegans expressing human R1441C- and G2019S-LRRK2, LRRK2-IN1 rescues the behavioral deficit characteristic of dopaminergic impairment. [2] In mouse fibroblasts, LRRK2-IN1 reduces cell motility. [3] In AsPC-1 and HCT116 cell lines, LRRK2-IN-1 shows anti-proliferative and pro-apoptotic properties, induces G1 and G2/M cell cycle arrest and inhibits DCLK1 mRNA and protein expression. [4]

In wild type male C57BL/6 mice, LRRK2-IN-1 (100 mg/kg, i.p.) inhibits Ser910 and Ser935 dephosphorylation of LRRK2 in the kidney, while no effects in the brain. [1]

IC50 determination: Active GST-LRRK2 (1326-2527), GST-LRRK2 [G2019S] (1326-2527), GST-LRRK2 [A2016T] (1326-2527) and GST-LRRK2 [A2016T+G2019S] (1326-2527) enzyme is purified with glutathione sepharose from HEK293 cell lysate 36 h following transient transfection of the appropriate cDNA constructs. Peptide kinase assays, performed in duplicate, are set up in a total volume of 40 μL containing 0.5 μg LRRK2 kinase (which at approximately 10% purity gives a final concentration of 8 nM) in 50 mM Tris/HCl, pH 7.5, 0.1 mM EGTA, 10 mM MgCl2, 20 μM Nictide, 0.1 μM [γ-32P]ATP (~500 cpm/pmol) and the indicated concentrations of inhibitor dissolved in DMSO. After incubation for 15 min at 30 °C, reactions are terminated by spotting 35 μL of the reaction mix onto P81 phosphocellulose paper and immersion in 50 mM phosphoric acid. Samples are washed extensively and the incorporation of [γ-32P]ATP into Nictide is quantified by Cerenkov counting. IC50 values are calculated with GraphPad Prism using non-linear regression analysis.

Cells are seeded into a 96-well tissue culture plate in triplicate. The cells are cultured in the presence of LRRK2-IN-1 with DMSO as a vehicle at 0, 0.31, 0.63, 1, 2, and 5, 10, and 20 μM. 48 h post treatment, 10 μL of TACS MTT Reagent (RND Systems) is added to each well and the cells are incubated at 37°C until dark crystalline precipitate became visible in the cells. 100 μL of 266 mM NH4OH in DMSO is then added to the wells and placed on a plate shaker at low speed for 1 minute. After shaking, the plate is allowed to incubate for 10 minutes protected from light and the OD550 for each well is read using a microplate reader. The results are averaged and calculated as a percentage of the DMSO (vehicle) control +/- the standard error of the mean.(Only for Reference)