Biology subjects

Chartier-Harlin, M.-C.

Publications and source records attributed to Chartier-Harlin, M.-C..

4 recordsLinked to original sources

bioRxiv2025

Multi-cohort, cross-species urinary proteomics reveals signatures of LRRK2 dysfunction in Parkinsons disease

Pathogenic mutations in Leucine-rich repeat kinase 2 (LRRK2) are the predominant genetic cause of Parkinsons disease (PD) and often increase kinase activity, making LRRK2 inhibitors promising treatment options. Although LRRK2 kinase inhibitors are advancing clinically, non-invasive readouts of LRRK2-linked pathway modulation remain limited. Profiling urinary proteomes from 1,215 individuals across three cohorts and integrating whole-genome sequencing from >500 participants to map genotype-proteome associations, we identified 177 urinary proteins associated with pathogenic LRRK2, enriched for lysosomal/glycosphingolipid, immune, and membrane-trafficking pathways. Machine learning narrowed the features to a cohort-agnostic 30-protein panel that classified G2019S carriers with a mean ROC AUC of 0.91 across independent tests. To evaluate translation, we performed multi-organ and urinary proteomics in rat gain- and loss-of-function models (BAC-LRRK2G2019S and Lrrk2KO) and after Lrrk2 inhibition (MLi-2 and PF-475), revealing tissue-specific responses--strongest in kidney--and cross-species overlap, including 24 brain proteins detectable in human urine. Rat-derived perturbations predicted LRRK2 mutation status in patients (AUC 0.75) and reversed with Lrrk2 inhibition, supporting their pharmacodynamic utility. Together, our findings establish urine as a scalable, non-invasive matrix that captures systemic and brain-relevant consequences of LRRK2 dysfunction and nominate candidate pharmacodynamic markers set to support LRRK2-directed trials.

systems biology↗

bioRxiv2025

A regulatory loop regulating signaling between LRRK2 and PP2A in cellular models of Parkinsons disease

Mutations in Leucine-rich repeat kinase 2 (LRRK2) are the most frequent cause of late-onset familial and idiopathic Parkinsons disease (PD), known to date. Importantly, recent data from post-mortem tissue as well as biomarker studies suggest that independent of mutations, increased kinase activity of LRRK2 plays an essential role in idiopathic PD pathogenesis. Despite extensive research on LRRK2, its activation mechanism(s) and how the various mutations result in increased kinase activity and neuronal death is still not completely understood. Accumulating evidence points to LRRK2 phospho-regulation, both auto-phosphorylation and phosphorylation by other kinases, as one potential molecular trigger of its activation. LRRK2 activation and localization is regulated by phosphatases such as Protein phosphatase 1 (PP1) and Protein phosphatase 2A (PP2A), however the exact mechanism of this phospho-regulation is not known. Our data reveal that in vitro PP2A dephosphorylates sites within the RocCOR-GTPase domain of LRRK2 and as a result de-stabilizes LRRK2 dimers, with consequent reduction of its kinase activity. Strikingly, our data further highlight that LRRK2 in turn phosphorylates the catalytic subunit of the PP2A holoenzyme PPP2CA at its critical residue T304. Furthermore, LRRK2-mediated phosphorylation of PP2CA T304 alters the methylation of the C-terminus, which is crucial for both holoenzyme formation and catalytic activity. Importantly, expression of WT-PPP2CA protects from LRRK2-G2019S induced neuronal cell death, while PPP2CA-T304 mutants fail to do so, suggesting that impaired PP2A holoenzyme formation might be detrimental for LRRK2-PD.

neuroscience↗

bioRxiv2023

A potential patient stratification biomarker for Parkinson's disease based on LRRK2 kinase-mediated centrosomal alterations in peripheral blood-derived cells

Parkinsos disease (PD) is a common neurodegenerative movement disorder and leucine-rich repeat kinase 2 (LRRK2) is a promising therapeutic target for disease intervention. However, the ability to stratify patients who will benefit from such treatment modalities based on shared etiology is critical for the success of disease-modifying therapies. Ciliary and centrosomal alterations are commonly associated with pathogenic LRRK2 kinase activity and can be detected in many cell types. We previously found centrosomal deficits in immortalized lymphocytes from G2019S-LRRK2 PD patients. Here, to investigate whether such deficits may serve as a potential blood biomarker for PD which is susceptible to LRKK2 inhibitor treatment, we characterized patient-derived cells from distinct PD cohorts. We report centrosomal alterations in peripheral cells from a subset of early-stage idiopathic PD patients which is mitigated by LRRK2 kinase inhibition, supporting a role for aberrant LRRK2 activity in idiopathic PD. Centrosomal defects are detected in R1441G-LRRK2 and G2019S-LRRK2 PD patients and in non-manifesting LRRK2 mutation carriers, indicating that they acumulate prior to a clinical PD diagnosis. They are present in immortalized cells as well as in primary lymphocytes from peripheral blood. These findings indicate that analysis of centrosomal defects as a blood-based patient stratification biomarker may help nominate PD patients who will benefit from LRRK2-related therapeutics. One-sentence summaryPeripheral blood-derived cells can be employed to stratify Parkinsos disease patients most likely to respond to LRRK2-related therapeutics.

neuroscience↗

bioRxiv2019

Transcriptomic signatures of brain regional vulnerability to Parkinson’s disease

The molecular mechanisms underlying the caudal-to-rostral progression of Lewy body pathology in Parkinsons disease (PD) remain poorly understood. Here, we aimed to unravel transcriptomic signatures across brain regions involved in Braak Lewy body stages in non-neurological controls and PD donors. Using human postmortem brain datasets of non-neurological adults from the Allen Human Brain Atlas, we identified expression patterns related to PD progression, including genes found in PD genome-wide associations studies: SNCA, ZNF184, BAP1, SH3GL2, ELOVL7, and SCARB2. We confirmed these patterns in two datasets of non-neurological subjects (Genotype-Tissue Expression project and UK Brain Expression Consortium) and found altered patterns in two datasets of PD patients. Additionally, co-expression analysis across vulnerable regions identified two modules associated with dopamine synthesis, the motor and immune system, blood-oxygen transport, and contained microglial and endothelial cell markers, respectively. Alterations in genes underlying these region-specific functions may contribute to the selective regional vulnerability in PD brains.

neuroscience↗