LRRK2-IN-1 (Synonyms: Leucine-rich repeat kinase 2 IN-1)

Kinase experiment:

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.

Cell experiment:

Cells (104 cells per well) 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 is added to each well and the cells are incubated at 37°C until dark crystalline precipitate become 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.

Animal experiment:

LRRK2-IN-1 is dissolved in Captisol and administered by intraperitoneal injection into wild type male C57BL/6 mice at a dose of 100 mg/kg. Control mice are injected with an equal volume of Captisol. At 1 and 2 h time points, mice are extinguwashed by cervical dislocation and kidney and brain tissue rapidly dissected and snap-frozen in liquid nitrogen.

References:

[1]. Hermanson SB, et al. Screening for Novel LRRK2 Inhibitors Using a High-Throughput TR-FRET Cellular Assay for LRRK2 Ser935 Phosphorylation.PLoS One. 2012;7(8):e43580. Epub 2012 Aug 28.
[2]. Deng, Xianming., et al. Characterization of a selective inhibitor of the Parkinson's disease kinase LRRK2. Nature Chemical Biology (2011), 7(4), 203-205.
[3]. Koshibu K, et al. Alternative to LRRK2-IN-1 for Pharmacological Studies of Parkinson's Disease. Pharmacology. 2015;96(5-6):240-7.
[4]. Weygant N, et al. Small molecule kinase inhibitor LRRK2-IN-1 demonstrates potent activity against colorectal and pancreatic cancer through inhibition of doublecortin-like kinase 1. Mol Cancer. 2014 May 6;13:103.