MLi-2, a Potent, Selective, and Centrally Active Compound for Exploring the Therapeutic Potential and Safety of LRRK2 Kinase Inhibition

  • J Pharmacol Exp Ther. 2015 Dec;355(3):397-409. doi: 10.1124/jpet.115.227587.
Matthew J Fell  1 ,  Christian Mirescu  2 ,  Kallol Basu  2 ,  Boonlert Cheewatrakoolpong  2 ,  Duane E DeMong  2 ,  J Michael Ellis  2 ,  Lynn A Hyde  2 ,  Yinghui Lin  2 ,  Carrie G Markgraf  2 ,  Hong Mei  2 ,  Michael Miller  2 ,  Frederique M Poulet  2 ,  Jack D Scott  2 ,  Michelle D Smith  2 ,  Zhizhang Yin  2 ,  Xiaoping Zhou  2 ,  Eric M Parker  2 ,  Matthew E Kennedy  2 ,  John A Morrow  2
Affiliations
  • 1. Neuroscience Discovery (M.J.F., C.M., M.E.K) and Discovery Chemistry (J.M.E), Merck Research Laboratories, Boston, Massachusetts; Discovery Chemistry (K.B., D.E.D., M.M., J.D.S.), Pharmacology (B.C., L.A.H., Y.L., E.M.P., M.D.S., Z.Y., X.Z.), Pathology and Cellular Toxicology (C.G.M., F.M.P), and Pharmacokinetics (H.M.), Merck Research Laboratories, Kenilworth, New Jersey; Neuroscience Discovery, Merck Research Laboratories, West Point, Pennsylvania (J.A.M.) [email protected].
  • 2. Neuroscience Discovery (M.J.F., C.M., M.E.K) and Discovery Chemistry (J.M.E), Merck Research Laboratories, Boston, Massachusetts; Discovery Chemistry (K.B., D.E.D., M.M., J.D.S.), Pharmacology (B.C., L.A.H., Y.L., E.M.P., M.D.S., Z.Y., X.Z.), Pathology and Cellular Toxicology (C.G.M., F.M.P), and Pharmacokinetics (H.M.), Merck Research Laboratories, Kenilworth, New Jersey; Neuroscience Discovery, Merck Research Laboratories, West Point, Pennsylvania (J.A.M.).
PMID: 26407721 DOI: 10.1124/jpet.115.227587
Abstract

Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most common genetic cause of familial and sporadic Parkinson's disease (PD). That the most prevalent mutation, G2019S, leads to increased kinase activity has led to a concerted effort to identify LRRK2 kinase inhibitors as a potential disease-modifying therapy for PD. An internal medicinal chemistry effort identified several potent and highly selective compounds with favorable drug-like properties. Here, we characterize the pharmacological properties of cis-2,6-dimethyl-4-(6-(5-(1-methylcyclopropoxy)-1H-indazol-3-yl)pyrimidin-4-yl)morpholine (MLi-2), a structurally novel, highly potent, and selective LRRK2 kinase inhibitor with central nervous system activity. MLi-2 exhibits exceptional potency in a purified LRRK2 kinase assay in vitro (IC50 = 0.76 nM), a cellular assay monitoring dephosphorylation of LRRK2 pSer935 LRRK2 (IC50 = 1.4 nM), and a radioligand competition binding assay (IC50 = 3.4 nM). MLi-2 has greater than 295-fold selectivity for over 300 kinases in addition to a diverse panel of receptors and ion channels. Acute oral and subchronic dosing in MLi-2 mice resulted in dose-dependent central and peripheral target inhibition over a 24-hour period as measured by dephosphorylation of pSer935 LRRK2. Treatment of MitoPark mice with MLi-2 was well tolerated over a 15-week period at brain and plasma exposures >100× the in vivo plasma IC50 for LRRK2 kinase inhibition as measured by pSer935 dephosphorylation. Morphologic changes in the lung, consistent with enlarged type II pneumocytes, were observed in MLi-2-treated MitoPark mice. These data demonstrate the suitability of MLi-2 as a compound to explore LRRK2 biology in cellular and animal models.

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