G2019S selective LRRK2 kinase inhibitor abrogates mitochondrial DNA damage.

Area of Science:

• Neuroscience
• Genetics
• Pharmacology

Background:

• Pathogenic mutations in Leucine-rich repeat kinase 2 (LRRK2) are a common cause of Parkinson's disease (PD).
• The G2019S LRRK2 variant, the most frequent mutation, leads to elevated kinase activity and has been linked to mitochondrial DNA (mtDNA) damage.
• LRRK2 kinase inhibitors are under clinical investigation for PD treatment.

Purpose of the Study:

• To evaluate the efficacy of a G2019S mutant-selective LRRK2 inhibitor compared to a non-selective inhibitor in reversing mtDNA damage.
• To explore the potential of a precision medicine approach for LRRK2 G2019S PD by targeting the specific mutant activity.

Main Methods:

• Utilized a G2019S mutant-selective inhibitor (EB-42168) and a non-selective inhibitor (MLi-2).
• Assessed LRRK2 kinase inhibition by measuring LRRK2 phosphorylation at Ser935/Ser1292 via quantitative western immunoblot analysis.
• Quantified mtDNA damage using the Mito DNA_DX assay in cellular models and patient cells.

Main Results:

• EB-42168 selectively inhibited G2019S LRRK2 phosphorylation, while MLi-2 inhibited both wild-type and G2019S LRRK2.
• Acute treatment with EB-42168 reduced LRRK2 phosphorylation and restored mtDNA damage to healthy control levels.
• mtDNA damage levels dynamically returned to baseline within 2 hours of inhibitor washout, and mitophagy defects were not rescued by kinase inhibition.

Conclusions:

• A G2019S mutant-selective LRRK2 inhibitor effectively reversed mtDNA damage in relevant models, demonstrating the potential of precision medicine for LRRK2 G2019S PD.
• mtDNA damage may serve as a pharmacodynamic biomarker for assessing LRRK2 kinase activity in small molecule development and clinical trials.