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.

中文翻译：

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MLi-2是一种有效的，选择性的，具有中心活性的化合物，可用于探索LRRK2激酶抑制作用的治疗潜力和安全性。

富含亮氨酸的重复激酶2（LRRK2）基因中的突变是家族性和散发性帕金森氏病（PD）的最常见遗传原因。最普遍的突变G2019S导致激酶活性增强，促使人们共同努力，将LRRK2激酶抑制剂鉴定为PD的潜在疾病缓解疗法。内部药物化学研究确定了几种具有良好类药物性质的有效且高度选择性的化合物。在这里，我们表征了顺式-2,6-二甲基-4-（6-（5-（1-甲基环丙氧基）-1H-吲唑-3-基）嘧啶-4-基）吗啉（MLi-2）的药理特性，一种结构新颖，高效且具有选择性的LRRK2激酶抑制剂，具有中枢神经系统活性。MLi-2在纯化的LRRK2激酶体外试验中表现出非凡的效能（IC50 = 0.76 nM），监测LRRK2 pSer935 LRRK2去磷酸化的细胞测定（IC50 = 1.4 nM）和放射性配体竞争结合测定（IC50 = 3.4 nM）。除了多种受体和离子通道外，MLi-2对300多种激酶的选择性超过295倍。通过对pSer935 LRRK2进行去磷酸化测量，MLi-2小鼠的急性口服和亚慢性给药导致24小时内剂量依赖性中枢和外周靶标抑制。用MLi-2治疗MitoPark小鼠在15周内的大脑和血浆暴露> 100倍体内血浆IC50对LRRK2激酶抑制作用的耐受性达到15周（通过pSer935脱磷酸化测量），耐受性良好。在经MLi-2处理的MitoPark小鼠中观察到了肺部形态变化，与II型肺细胞增大有关。