Biology subjects

Goralski, T.

Publications and source records attributed to Goralski, T..

3 recordsLinked to original sources

bioRxiv2024

Cortical synaptic vulnerabilities revealed in a α-synuclein aggregation model of Parkinson's disease

-Synuclein aggregates characterize -synucleinopathies, including Parkinsons disease and Dementia with Lewy bodies. A majority of people with these disorders experience cognitive decline, and its extent correlates with cortical -synuclein pathology. Mechanisms by which pathology targets cortical circuits remain to be understood so that the debilitating non-motor impairments can be addressed. Overt neuronal loss is not a major feature of cortical pathology, but a reduction of presynaptic sites has been reported at late stages of PD. We here define excitatory synapses as neuronal loci affected by -synuclein aggregation, showing that they are progressively lost, and identify temporal and spatial patterns of synaptic vulnerability. Results were obtained in a mouse model using intrastriatal injection of pre-formed -synuclein fibrils to template the aggregation of endogenous -synuclein in cortical neurons. Lewy neurite-like aggregates were predominantly observed in axons. Super-resolved imaging showed -synuclein aggregation within cortical synapses and revealed that synaptic aggregation is most severe proximal to Lewy neurite-like structures and linked to the earliest detectable loss of excitatory synapses. Excitatory synapses also exhibited ultrastructural aberrations, including a redistribution of pre- and post-synaptic protein clusters away from contact sites and reduced synaptic vesicle size. As pathology advanced, VGLUT1-positive intracortical synapses, enriched in -synuclein, were progressively vulnerable in this striatal seeding model, while VGLUT2-positive long-range synapses with minimal -synuclein were spared. Inhibitory synapses were not affected. In agreement with a disruptive role of synaptic -synuclein aggregation, super-resolved mesoscale imaging determined that synaptic but not non-synaptic -synuclein pathology is correlated with excitatory synapse loss. Physiological recordings confirmed impaired excitatory neurotransmission. Pathology propagation tracked cortical connectivity, with intra-column synapse loss correlated between interconnected layers V and II/III. Contralateral areas receiving projections from pathologic layer V also exhibited synapse loss. These findings reveal synapses as principal cellular loci of -synuclein pathology and define how molecular and circuit-based mechanisms underlie the cortical progression of synaptic pathology in -synucleinopathies.

neuroscience↗

bioRxiv2023

Human Endogenous Retrovirus Expression is Dynamically Regulated in Parkinson's Disease

Parkinsons disease (PD) is a progressive, debilitating neurodegenerative disease that afflicts approximately every 1000th individual. Recently, activation of genomic transposable elements (TE) has been suggested as a potential driver of PD onset. However, it is unclear where, when, and to what extent TEs are dysregulated in PD. Here, we performed a multi-tissue transcriptional analysis of multiple patient cohorts and identified TE transcriptional activation as a hallmark of PD. We find that PD patients exhibit up-regulation primarily of human endogenous retrovirus (HERV) transcripts in prefrontal cortex tissue, prefrontal neurons as well as in blood, and we demonstrate that TE activation in the blood is highest at the time of PD diagnosis. Supporting a potentially causal association between ERV dysregulation and PD heterogeneity, reduced gene dosage of the TE repressor Trim28 triggers transcriptional changes highly correlated to those measured in animal models of synucleinopathy (PFF-injection), and importantly, to those exhibited by patients themselves. These data identify ERV up-regulation as a common feature of central and peripheral PD etiology, and highlight potential roles for Trim28-dependent TEs in stratifying and monitoring PD and treatment compliance.

neuroscience↗

bioRxiv2023

Spatial transcriptomics reveals molecular dysfunction associated with Lewy pathology

Lewy pathology composed of -synuclein is the key pathological hallmark of Parkinsons disease (PD), found both in dopaminergic neurons that control motor function, and throughout cortical regions that control cognitive function. Recent work has investigated which dopaminergic neurons are most susceptible to death, but little is known about which neurons are vulnerable to developing Lewy pathology and what molecular changes an aggregate induces. In the current study, we use spatial transcriptomics to selectively capture whole transcriptome signatures from cortical neurons with Lewy pathology compared to those without pathology in the same brains. We find, both in PD and in a mouse model of PD, that there are specific classes of excitatory neurons that are vulnerable to developing Lewy pathology in the cortex. Further, we identify conserved gene expression changes in aggregate-bearing neurons that we designate the Lewy-associated molecular dysfunction from aggregates (LAMDA) signature. This gene signature indicates that neurons with aggregates downregulate synaptic, mitochondrial, ubiquitin-proteasome, endo-lysosomal, and cytoskeletal genes and upregulate DNA repair and complement/cytokine genes. However, beyond DNA repair gene upregulation, we find that neurons also activate apoptotic pathways, suggesting that if DNA repair fails, neurons undergo programmed cell death. Our results identify neurons vulnerable to Lewy pathology in the PD cortex and identify a conserved signature of molecular dysfunction in both mice and humans.

neuroscience↗