Taoufik, E. | bioRxiv Science

bioRxiv2024

Proteostasis dysregulation in p.A53T-α-Synuclein iPSC-derived astrocytes exacerbates neurodegeneration in a Parkinson's disease model with Lewy-like pathology

Alpha-Synuclein (Syn) plays a central role in Parkinsons disease (PD) and the p.A53T mutation causes an early-onset familial form of PD with severe manifestations. The pathological effects of the p.A53T-Syn mutation have been extensively investigated in neurons, yet the consequences on astrocytes and astrocytic contribution to PD pathology are understudied. Here, we differentiated induced pluripotent stem cells from PD patients carrying the p.A53T-Syn mutation to astrocytes, which uncovered cell-intrinsic phenotypes, including calcium dyshomeostasis and accumulation of protein aggregates. Proteomic profiling and functional analyses revealed perturbed protein catabolic processes, involving the proteasome and autophagy, associated with lysosomal malfunction. Dopamine neurons co-cultured with p.A53T-Syn astrocytes displayed exacerbated neurodegeneration with hallmark Lewy-like pathologies, reversed by control astrocytes at least due to their ability to resolve neuronal Syn aggregates by endocytic clearance. Our findings underscore a critical impact of p.A53T-Syn on astrocytic protein quality control mechanisms, positioning astrocytes as important contributors to PD neuropathology. HighlightsO_LIiPSC-derived astrocytes from PD patients with the p.A53T-Syn mutation display cell-autonomous pathological phenotypes and toxic Syn accumulation C_LIO_LIProteome and functional analyses reveal failure of major proteostasis mechanisms in p.A53T-Syn astrocytes, largely related to lysosomal malfunction C_LIO_LIInherent Lewy-like pathological features are identified in p.A53T-Syn astrocyte-neuron co-cultures C_LIO_LIp.A53T-Syn astrocytes induce PD-relevant neuropathology to healthy neurons C_LIO_LIControl but not p.A53T-Syn astrocytes alleviate neuropathology in co-cultured neurons C_LI

neuroscience↗

bioRxiv2020

High Content Screening and Proteomic Analysis Identify the Kinase Inhibitor BX795 as a Potent Neuroprotective Compound in a Patient-Derived Model of Parkinson's Disease

Combining high throughput screening approaches with induced pluripotent stem cell (iPSC)-based disease modeling represents a promising unbiased strategy to identify therapies for neurodegenerative disorders. Here we applied high content imaging on iPSC-derived neurons from patients with familial Parkinsons disease bearing the G209A (p.A53T) -synuclein (Syn) mutation and launched a screening campaign on a small kinase inhibitor library. We thus identified the multi-kinase inhibitor BX795 that at a single dose effectively restores disease-associated neurodegenerative phenotypes. Proteomics profiling mapped the molecular pathways underlying the protective effects of BX795, comprising a cohort of 118 protein-mediators of the core biological processes of RNA metabolism, protein synthesis, modification and clearance, and stress response, all linked to the mTORC1 signaling hub. In agreement, expression of human p.A53T-Syn in neuronal cells affected key components of the mTORC1 pathway resulting in aberrant protein synthesis that was restored in the presence of BX795 with concurrent facilitation of autophagy. Taken together, we have identified a promising small molecule with neuroprotective actions as candidate therapeutic for PD and other protein conformational disorders.

neuroscience↗