Biology subjects

Joselin, A.

Publications and source records attributed to Joselin, A..

4 recordsLinked to original sources

bioRxiv2026

VDAC1 regulates stress-associated matrix localization of DJ-1 to support mitochondrial homeostasis and neuronal survival

DJ-1 is a redox-sensitive protein implicated in early-onset Parkinson's disease, and its mitochondrial localization protects against oxidative stress, but the mechanisms regulating its submitochondrial targeting and functional impact on mitochondrial integrity remain poorly understood. We identify voltage-dependent anion channel 1 (VDAC1) as a regulator of the submitochondrial distribution of DJ-1 during stress. Endogenous DJ-1 interacted with VDAC1, and loss of VDAC1 reduced stress-induced DJ-1 accumulation within the mitochondrial matrix. VDAC1-deficient neurons exhibited mitochondrial fragmentation, impaired oxidative phosphorylation, reduced ATP levels, altered reactive oxygen species (ROS) responses, and increased sensitivity to MPP+;. Matrix-targeted, but not outer-membrane-targeted, DJ-1 rescued basal, ATP-linked, and maximal respiration, improved mitochondrial morphology, and enhanced neuronal survival. ATP synthase inhibition also rapidly increased mitochondrial DJ-1, suggesting bioenergetic stress promotes its mitochondrial accumulation. Our findings identify compartment-specific localization as a key determinant of DJ-1 function and establish VDAC1-dependent matrix targeting as a critical mechanism supporting mitochondrial integrity during stress.

neuroscience↗

bioRxiv2025

Integrating simulated and experimental data to identify mitochondrial bioenergetic defects in Parkinson's Disease models

Mitochondrial bioenergetics are vital for ATP production and are associated with several diseases, including Parkinsons Disease. Here, we simulated a computational model of mitochondrial ATP production to interrogate mitochondrial bioenergetics under physiological and pathophysiological conditions, and provide a data resource that can be used to interpret mitochondrial bioenergetics experiments. We first characterised the impact of several common respiratory chain impairments on experimentally-observable bioenergetic parameters. We then established an analysis pipeline to integrate simulations with experimental data and predict the molecular defects underlying experimental bioenergetic phenotypes. We applied the pipeline to data from Parkinsons Disease models. We verified that the impaired bioenergetic profile previously measured in Parkin knockout neurons can be explained by increased mitochondrial uncoupling. We then generated primary cortical neurons from a Pink1 KO mouse model of Parkinsons, and measured reduced OCR capacity and increased resistance to Complex III inhibition. Here, our pipeline predicted that multiple respiratory chain impairments are required to explain this bioenergetic phenotype. Finally, we provide all simulated data as a user-friendly resource that can be used to interpret mitochondrial bioenergetics experiments, predict underlying molecular defects, and inform experimental design. HighlightsO_LIThe complexity of mitochondrial bioenergetics can make experimental data difficult to interpret. C_LIO_LIWe simulated a computational model of mitochondrial bioenergetics in healthy and pathological conditions, and established an analysis pipeline to integrate model simulations with experimental data. C_LIO_LIWe applied the pipeline to data from Parkinsons Disease models to predict the molecular defects underlying Parkinsons-related pathology. C_LIO_LIWe provide all outputs in a user-friendly Excel file, which serves as a valuable resource to the community for insight into the effects of pathology on mitochondrial bioenergetics and for interpretation of experimental results. C_LI

neuroscience↗

bioRxiv2022

Genetic and pharmacological reduction of CDK14 mitigates synucleinopathy

Parkinsonas disease (PD) is a debilitating neurodegenerative disease characterized by the loss of midbrain dopaminergic neurons (DaNs) and the abnormal accumulation of -Synuclein (-Syn) protein. Currently, no treatment can slow nor halt the progression of PD. Multiplications and mutations of the -Syn gene (SNCA) cause PD-associated syndromes and animal models that overexpress -Syn replicate several features of PD. Decreasing total -Syn levels, therefore, is an attractive approach to slow down neurodegeneration in patients with synucleinopathy. We previously performed a genetic screen for modifiers of -Syn levels and identified CDK14, a kinase of largely unknown function as a regulator of -Syn. To test the potential therapeutic effects of CDK14 reduction in PD, we ablated Cdk14 in the -Syn preformed fibrils (PFF)-induced PD mouse model. We found that loss of Cdk14 mitigates the grip strength deficit of PFF-treated mice and ameliorates PFF-induced cortical -Syn pathology, indicated by reduced numbers of pS129 -Syn-containing cells. In primary neurons, we found that Cdk14 depletion protects against the propagation of toxic -Syn species. We further validated these findings on pS129 -Syn levels in PD patient neurons. Finally, we leveraged the recent discovery of a covalent inhibitor of CDK14 to determine whether this target is pharmacologically tractable in vitro and in vivo. We found that CDK14 inhibition decreases total and pathologically aggregated -Syn in human neurons, in PFF- challenged rat neurons and in the brains of -Syn-humanized mice. In summary, we suggest that CDK14 represents a novel therapeutic target for PD-associated synucleinopathy.

neuroscience↗

bioRxiv2022

PFTK1 kinase regulates axogenesis during development via RhoA activation.

PFTK1/Eip63E is a member of the Cyclin-dependent kinases (CDKs) family and plays an important role in normal cell cycle progression. Eip63E expresses primarily in postnatal and adult nervous system in Drosophila melanogaster but its role in CNS development remains unknown. We sought to understand the function of Eip63E in the CNS by studying the fly ventral nerve cord during development. Our results demonstrate that Eip63E regulates axogenesis in neurons and its deficiency leads to neuronal defects. Functional interaction studies performed using the same system identify an interaction between Eip63E and the small GTPase Rho1. Furthermore, deficiency of Eip63E homolog in mice, PFTK1, in a newly generated PFTK1 knockout mice results in increased axonal outgrowth confirming that the developmental defects observed in the fly model are due to defects in axogenesis. Importantly, RhoA phosphorylation and activity is affected by PFTK1 in primary neuronal cultures. We here report that GDP bound inactive RhoA is a substrate of PFTK1 and PFTK1 phosphorylation is required for RhoA activity. In conclusion, our work establishes an unreported neuronal role of PFTK1 in axon development mediated by phosphorylation and activation of GDP-bound RhoA. The results presented add to our understanding of the role of Cdks in the maintenance of RhoA mediated axon growth and its impact on CNS development and axonal regeneration.

neuroscience↗