Dysregulation of mitochondria-lysosome contacts by GBA1 dysfunction in dopaminergic neuronal models of Parkinson’s disease

Mitochondria-lysosome contacts are recently identified sites for mediating crosstalk between both organelles, but their role in normal and diseased human neurons remains unknown. In this study, we demonstrate that mitochondria-lysosome contacts can dynamically form in the soma, axons, and dendrites of human neurons, allowing for their bidirectional crosstalk. Parkinson’s disease patient derived neurons harboring mutant GBA1 exhibited prolonged mitochondria-lysosome contacts due to defective modulation of the untethering protein TBC1D15, which mediates Rab7 GTP hydrolysis for contact untethering. This dysregulation was due to decreased GBA1 (β-glucocerebrosidase (GCase)) lysosomal enzyme activity in patient derived neurons, and could be rescued by increasing enzyme activity with a GCase modulator. These defects resulted in disrupted mitochondrial distribution and function, and could be further rescued by TBC1D15 in Parkinson’s patient derived GBA1-linked neurons. Together, our work demonstrates a potential role of mitochondria-lysosome contacts as an upstream regulator of mitochondrial function and dynamics in midbrain dopaminergic neurons in GBA1-linked Parkinson’s disease.


nature research | reporting summary
April 2020 Field-specific reporting Please select the one below that is the best fit for your research. If you are not sure, read the appropriate sections before making your selection.

Life sciences Behavioural & social sciences Ecological, evolutionary & environmental sciences
For a reference copy of the document with all sections, see nature.com/documents/nr-reporting-summary-flat.pdf

Life sciences study design
All studies must disclose on these points even when the disclosure is negative. All sample sizes are listed in detail in the figure legends and main text. No statistical method was used to determine sample sizes. Based on previous publications, a reasonable sample size was chosen to achieve statistical significance and minimize cost.
In live-cell imaging experiments, any cells were excluded if they were unresolved by fluorescence signal. No data was excluded in the analysis stage.
For all statistical tests, data were from N # 3 independent experiments (biological replicates). All attempts at replication were successful in all experiments. Also, additional steps were taken to ensure rigor and reproducibility, as follows: 1) scientific questions were addressed using complementary technical approaches to ensure that the findings were robust; 2) for studies involving multiple different experimental conditions in the same line, studies were performed on neurons originating from the same batch.
Neurons from each line or condition were randomly allocated in different wells and randomly assigned into different experimental groups. Since patients' neurons were grouped based on the genotype and compared with the respective isogenic control, no additional randomization was applicable for our experiments.
Blinding was not applicable for the characterization of mitochondria-lysosome contact sites in wild-type control neurons because all neurons were cultured in the same condition, and analyzed using the same methods. The experimenters who performed the quantification of the live cell images or immunostainings were blinded to the genotype/treatment of the samples to exclude bias.