LRRK2 G2019S-induced mitochondrial DNA damage is LRRK2 kinase dependent and inhibition restores mtDNA integrity in Parkinson’s disease

Abstract

Mutations in leucine-rich repeat kinase 2 (LRRK2) are associated with increased risk for developing Parkinson's disease (PD). Previously, we found that LRRK2 G2019S mutation carriers have increased mitochondrial DNA (mtDNA) damage and after zinc finger nuclease-mediated gene mutation correction, mtDNA damage was no longer detectable. While the mtDNA damage phenotype can be unambiguously attributed to the LRRK2 G2019S mutation, the underlying mechanism(s) is unknown. Here, we examine the role of LRRK2 kinase function in LRRK2 G2019S-mediated mtDNA damage, using both genetic and pharmacological approaches in cultured neurons and PD patient-derived cells. Expression of LRRK2 G2019S induced mtDNA damage in primary rat midbrain neurons, but not in cortical neuronal cultures. In contrast, the expression of LRRK2 wild type or LRRK2 D1994A mutant (kinase dead) had no effect on mtDNA damage in either midbrain or cortical neuronal cultures. In addition, human LRRK2 G2019S patient-derived lymphoblastoid cell lines (LCL) demonstrated increased mtDNA damage relative to age-matched controls. Importantly, treatment of LRRK2 G2019S expressing midbrain neurons or patient-derived LRRK2 G2019S LCLs with the LRRK2 kinase inhibitor GNE-7915, either prevented or restored mtDNA damage to control levels. These findings support the hypothesis that LRRK2 G2019S-induced mtDNA damage is LRRK2 kinase activity dependent, uncovering a novel pathological role for this kinase. Blocking or reversing mtDNA damage via LRRK2 kinase inhibition or other therapeutic approaches may be useful to slow PD-associated pathology.

Reply to “Mitochondrial DNA deletions discriminate affected from unaffected LRRK2 mutation carriers”

“…Other groups have also reported higher mtDNA damage in LRRK2 in vitro and in vivo models . We agree with the authors that their results support mtDNA damage as a promising biomarker of PD risk and progression in LRRK2 patients and suggest additional aspects of LRRK2 PD that are worthy of further investigation.…”

Genetic predispositions of Parkinson’s disease revealed in patient-derived brain cells

“…Fewer than 12% (8/67) of published studies used more than ten cell lines ( Fig. 3d) 37,42,56,70,79,84,92 . Interestingly, it has been estimated that sample sizes of 10-30 individuals per hiPSC study may be required to achieve a statistical power of 80%, assuming that the cellular readouts variance is high and the disease effect is small (>0.7 relative heterogeneity, which is the ratio between within-group standard deviation and mean group difference) 189 .…”

Long-Term Exposure to PFE-360 in the AAV-α-Synuclein Rat Model: Findings and Implications

“…In this respect, alterations in glutamatergic transmission in striatal slices from G2019S-LRRK2 transgenic animals were only observed when rotenone, a mitochondrial toxin, was also present, indicating that LRRK2 might only play a role in the diseased state, such as impaired DAergic neurotransmission (Tozzi et al, 2018). In support, recent studies have suggested that LRRK2 kinase activity is increased in substantia nigra in the AAV-␣-synuclein overexpression model and in rotenone models as well as in postmortem tissue from idiopathic PD patients (Howlett et al, 2017;Di Maio et al, 2018).…”