Elsevier

Neurobiology of Disease

Volume 144, October 2020, 105049
Neurobiology of Disease

LRRK2 kinase inhibitors reduce alpha-synuclein in human neuronal cell lines with the G2019S mutation

https://doi.org/10.1016/j.nbd.2020.105049Get rights and content
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Highlights

  • LRRK2 inhibitors reduced alpha-synuclein in multiple human iPSC-derived neural lines.

  • Prolonged treatment with LRRK2 inhibitors was not toxic to neurons.

  • LRRK2 may reduce alpha-synuclein via effects on the autophagy/lysosomal system.

Abstract

Kinase activating missense mutations in leucine-rich repeat kinase 2 (LRRK2) predispose to Parkinson's disease. Consequently, there is much interest in delineating LRRK2 biology, both in terms of gaining further insight into disease causes, and also determining whether or not LRRK2 is a potential Parkinson's disease therapeutic target. Indeed, many potent and selective small molecule inhibitors of LRRK2 have been developed and are currently being used for pre-clinical testing in cell and animal models. In the current study, we have obtained fibroblasts from four subjects with the common LRRK2 mutation, G2019S. Fibroblasts were reprogrammed to induced pluripotent stem cells and then to neural stem cells and ultimately neurons. Two clones for each of the human neural cell lines were then chronically treated with and without either of two distinct inhibitors of LRRK2 and effects on toxicity and Parkinson's disease related phenotypes were assessed. Cells with the G2019S mutation had a propensity to accumulate the pathological Parkinson's disease protein α-synuclein. Moreover, α-synuclein accumulation in the G2019S cells was significantly reduced with both LRRK2 inhibitors in seven of the eight cell lines studied. LRRK2 inhibitors also improved the nuclear morphology of G2019S cells and impacted on measures of autophagy and endoplasmic reticulum stress. Lastly, we did not find evidence of inhibitor toxicity under the chronic treatment conditions. These results add to evidence that LRRK2 inhibitors may have utility in the treatment of Parkinson's disease via reducing α-synuclein.

Keywords

LRRK2
Parkinson's disease
Kinase inhibitors
α-synuclein
Pluripotent stem cells
Lysosome
Neuron

Abbreviations

Leucine-rich repeat kinase 2
(LRRK2)
Parkinson's disease
(PD)
Induced pluripotent stem cell
(IPSC)
Neural stem cell
(NSC)
Dimethyl sulfoxide
(DMSO)
microtubule-associated protein 2
(MAP2)
4′6-diamidino-2-phenylindole
(DAPI)
microtubule-associated protein 1A/1B-light chain 3
(LC3)
lysosomal membrane associated protein 2
(LAMP2)
median fluorescence intensity
(MFI)
Tris buffered saline with 0.1% (v/v) Tween 20
(TBST)
stage-specific embryonic antigen 4
(SSEA4)
octomer binding protein 4
(OCT4)
sex determining region Y-box 2
(SOX2)
chaperone mediated autophagy
(CMA)
Nuclear C/EBP homologous protein
(CHOP)
bovine serum albumin
(BSA)
fetal bovine serum
(FBS)
endoplasmic reticulum
(ER)

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