Biology subjects

Praschberger, R.

Publications and source records attributed to Praschberger, R..

4 recordsLinked to original sources

bioRxiv2024

Parkinson's disease-associated Pink1 loss disrupts vesicle trafficking in ensheathing glia causing dopaminergic neuron synapse loss

Parkinsons disease (PD) is commonly associated with the loss of dopaminergic neurons in the substantia nigra, but many other cell types are affected even before neuron loss occurs. Recent studies have linked oligodendrocytes to early stages of PD, though their precise role is still unclear. PINK1 is mutated in familial PD, and through unbiased single-cell sequencing of the entire brain of Drosophila Pink1 models, we observed significant gene deregulation in ensheathing glia (EG); cells that share functional similarities with oligodendrocytes. We found that the loss of Pink1 leads to abnormalities in EG, similar to the reactive response of EG seen upon nerve injury. Using cell-type-specific transcriptomics, we identified deregulated genes in EG as potential functional modifiers. Specifically downregulating two trafficking factors in EG, Vps35 and Vps13, also mutated in PD, was sufficient to rescue neuronal function and protect against dopaminergic synapse loss. Our findings demonstrate that Pink1 loss in neurons triggers an injury-like response in EG, and that Pink1 loss in EG in turn disrupts neuronal function. Vesicle trafficking components, which may regulate membrane interactions between organelles in EG, seem to play a role in maintaining neuronal health and ultimately preventing dopaminergic synapse loss. Our work highlights the essential role of glial support cells in the pathogenesis of PD and identifies vesicle trafficking within these cells in disease progression.

neuroscience↗

bioRxiv2024

Behavioral screening defines three molecular Parkinsonism subgroups in Drosophila

Parkinsonism is defined by motor dysfunction, but the specific upstream molecular causes of these clinical symptoms can vary widely. We hypothesize that these causes converge onto a limited number of core cellular pathways. To investigate this, we created a new collection of 24 genetically very well-controlled animal models of familial forms of parkinsonism. Using unbiased behavioral screening and machine learning we identified three clusters of mutants that converge on (1) mitochondrial function; (2) retromer/vesicle trafficking; and (3) proteostasis/autophagy. Genes within each cluster have a similar genetic interaction profile and compounds that target specific molecular pathways ameliorate dopaminergic neuron dysfunction in a cluster-specific manner. This suggests that familial parkinsonism can be stratified into three broad functional groups and our findings pave the way for targeted biomarker discovery and drug development.

neuroscience↗

bioRxiv2022

Neuronal identity defines a-synuclein and tau toxicity

Pathogenic -synuclein and tau are critical drivers of neurodegeneration and their mutations cause neuronal loss in patients. Whether the underlying preferential neuronal vulnerability is a cell-type intrinsic property or a consequence of increased expression levels is an open question. Here, we explore cell-type specific -synuclein and tau expression in human brain datasets and use deep phenotyping as well as brain-wide single-cell RNA sequencing of >200 live neuron types in fruit flies to ask which cellular environments react most to -synuclein or tau toxicity. We detect phenotypic and transcriptomic evidence of differential neuronal vulnerability independent of -synuclein or tau expression levels. Comparing vulnerable with resilient neurons enabled us to identify molecular signatures associated with these differential responses. We used these to verify, and then predict resilient and vulnerable neuron subtypes in human brains. This confirms substantia nigra dopaminergic neurons to be sensitive to -synuclein, and we predict pathogenic tau vulnerable and protected cortical neuron subtypes. Our work indicates that cellular determinants confer selective vulnerability to specific types of amyloid toxicity, thus paving the way to leverage neuronal identity to uncover modifiers of neurodegeneration-associated toxic proteins.

neuroscience↗

bioRxiv2017

Mutations In Membrin/GOSR2 Reveal Stringent Secretory Pathway Demands Of Dendritic Growth And Synaptic Integrity

Mutations in the Golgi SNARE protein Membrin (encoded by the GOSR2 gene) cause progressive myoclonus epilepsy (PME). Membrin is a ubiquitously important protein mediating ER-to-Golgi membrane fusion, and hence it is unclear how these mutations result in a disorder restricted to the nervous system. Here we use a multi-layered strategy to elucidate the consequences of Membrin mutations from protein to neuron. We show that the pathogenic mutations cause partial reductions in SNARE-mediated membrane fusion. Importantly, these alterations were sufficient to profoundly impair dendritic growth in novel Drosophila models of GOSR2-PME. We also observed axonal trafficking abnormalities in this model, as well as synaptic malformations, trans-synaptic instability and hyperactive synaptic transmission. Our study highlights how dendritic growth is vulnerable even to subtle secretory pathway deficits, uncovers a previously uncharacterized role for Membrin in synaptic function, and provides a comprehensive explanatory basis for genotype-phenotype relationships in GOSR2-PME.

neuroscience↗