Dataset Information

Mitochondrial clearance and maturation of autophagosomes are compromised in LRRK2 G2019S familial Parkinson's disease patient fibroblasts.

ABSTRACT: This study utilized human fibroblasts as a preclinical discovery and diagnostic platform for identification of cell biological signatures specific for the LRRK2 G2019S mutation producing Parkinson's disease (PD). Using live cell imaging with a pH-sensitive Rosella biosensor probe reflecting lysosomal breakdown of mitochondria, mitophagy rates were found to be decreased in fibroblasts carrying the LRRK2 G2019S mutation compared to cells isolated from healthy subject (HS) controls. The mutant LRRK2 increased kinase activity was reduced by pharmacological inhibition and targeted antisense oligonucleotide treatment, which normalized mitophagy rates in the G2019S cells and also increased mitophagy levels in HS cells. Detailed mechanistic analysis showed a reduction of mature autophagosomes in LRRK2 G2019S fibroblasts, which was rescued by LRRK2 specific kinase inhibition. These findings demonstrate an important role for LRRK2 protein in regulation of mitochondrial clearance by the lysosomes, which is hampered in PD with the G2019S mutation. The current results are relevant for cell phenotypic diagnostic approaches and potentially for stratification of PD patients for targeted therapy.

SUBMITTER: Korecka JA

PROVIDER: S-EPMC6859523 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

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Mitochondrial clearance and maturation of autophagosomes are compromised in LRRK2 G2019S familial Parkinson's disease patient fibroblasts.

Korecka Joanna A JA Thomas Ria R Christensen Dan P DP Hinrich Anthony J AJ Ferrari Eliza J EJ Levy Simon A SA Hastings Michelle L ML Hallett Penelope J PJ Isacson Ole O

Human molecular genetics 20191001 19

This study utilized human fibroblasts as a preclinical discovery and diagnostic platform for identification of cell biological signatures specific for the LRRK2 G2019S mutation producing Parkinson's disease (PD). Using live cell imaging with a pH-sensitive Rosella biosensor probe reflecting lysosomal breakdown of mitochondria, mitophagy rates were found to be decreased in fibroblasts carrying the LRRK2 G2019S mutation compared to cells isolated from healthy subject (HS) controls. The mutant LRRK ...[more]

PMID: 31261377

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Project description:BACKGROUND:Mutations in leucine rich repeat kinase 2 (LRRK2) are the most common cause of familial Parkinson's disease (PD). Mitochondrial and autophagic dysfunction has been described as etiologic factors in different experimental models of PD. We aimed to study the role of mitochondria and autophagy in LRRK2 G2019S -mutation, and its relationship with the presence of PD-symptoms. METHODS:Fibroblasts from six non-manifesting LRRK2 G2019S -carriers (NM-LRRK2 G2019S ) and seven patients with LRRK2 G2019S -associated PD (PD-LRRK2 G2019S ) were compared to eight healthy controls (C). An exhaustive assessment of mitochondrial performance and autophagy was performed after 24-h exposure to standard (glucose) or mitochondrial-challenging environment (galactose), where mitochondrial and autophagy impairment may be heightened. RESULTS:A similar mitochondrial phenotype of NM-LRRK2 G2019S and controls, except for an early mitochondrial depolarization (54.14% increased, p?=?0.04), was shown in glucose. In response to galactose, mitochondrial dynamics of NM-LRRK2 G2019S improved (-?17.54% circularity, p?=?0.002 and +?42.53% form factor, p?=?0.051), probably to maintain ATP levels over controls. A compromised bioenergetic function was suggested in PD-LRRK2 G2019S when compared to controls in glucose media. An inefficient response to galactose and worsened mitochondrial dynamics (-?37.7% mitochondrial elongation, p?=?0.053) was shown, leading to increased oxidative stress. Autophagy initiation (SQTSM/P62) was upregulated in NM-LRRK2 G2019S when compared to controls (glucose +?118.4%, p?=?0.014; galactose +?114.44%, p?=?0.009,) and autophagosome formation increased in glucose media. Despite of elevated SQSTM1/P62 levels of PD-NM G2019S when compared to controls (glucose +?226.14%, p?=?0.04; galactose +?78.5%, p?=?0.02), autophagosome formation was deficient in PD-LRRK2 G2019S when compared to NM-LRRK2 G2019S (-?71.26%, p?=?0.022). CONCLUSIONS:Enhanced mitochondrial performance of NM-LRRK2 G2019S in mitochondrial-challenging conditions and upregulation of autophagy suggests that an exhaustion of mitochondrial bioenergetic and autophagic reserve, may contribute to the development of PD in LRRK2 G2019S mutation carriers.

Project description:Pathogenic mutations in LRRK2 cause Parkinson's disease (PD). The G2019S variant is the most common, which results in abnormally high kinase activity. Compounds that target LRRK2 kinase activity are currently being developed and tested in clinical trials. We recently found that G2019S LRRK2 causes mitochondrial DNA (mtDNA) damage and treatment with multiple classes of LRRK2 kinase inhibitors at concentrations associated with dephosphorylation of LRRK2 reversed mtDNA damage to healthy control levels. Because maintaining the normal function of LRRK2 in heterozygous G2019S LRRK2 carriers while specifically targeting the G2019S LRRK2 activity could have an advantageous safety profile, we explored the efficacy of a G2019S mutant selective LRRK2 inhibitor to reverse mtDNA damage in G2019S LRRK2 models and patient cells relative to non-selective LRRK2 inhibitors. Potency of LRRK2 kinase inhibition by EB-42168, a G2019S mutant LRRK2 kinase inhibitor, and MLi-2, a non-selective inhibitor, was determined by measuring phosphorylation of LRRK2 at Ser935 and/or Ser1292 using quantitative western immunoblot analysis. The Mito DNADX assay, which allows for the accurate real-time quantification of mtDNA damage in a 96-well platform, was performed in parallel. We confirmed that EB-42168 selectively inhibits LRRK2 phosphorylation on G2019S LRRK2 relative to wild-type LRRK2. On the other hand, MLi-2 was equipotent for wild-type and G2019S LRRK2. Acute treatment with EB-42168 inhibited LRRK2 phosphorylation and also restored mtDNA damage to healthy control levels. We further investigated the relationship between LRRK2 kinase activity, mtDNA damage and mitophagy. Levels of mtDNA damage caused by G2019S LRRK2 were fully re-established within 2 h of a LRRK2 inhibitor wash out and recovery experiment, indicating the mtDNA damage phenotype is highly dynamic. G2019S LRRK2 mitophagy defects were not alleviated with LRRK2 kinase inhibition, suggesting that mitophagy is not mechanistically regulating LRRK2 kinase-mediated reversal of mtDNA damage in this acute timeframe. Abrogation of mtDNA damage with the mutant selective tool inhibitor EB-42168 demonstrates the potential of a precision medicine approach for LRRK2 G2019S PD. Levels of mtDNA damage may serve as a potential pharmacodynamic biomarker of altered kinase activity that could be useful for small molecule development and clinical trials.

Dataset Information

Mitochondrial clearance and maturation of autophagosomes are compromised in LRRK2 G2019S familial Parkinson's disease patient fibroblasts.

Publications

Mitochondrial clearance and maturation of autophagosomes are compromised in LRRK2 G2019S familial Parkinson's disease patient fibroblasts.

Similar Datasets

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