Biology subjects

Ledreux, A.

Publications and source records attributed to Ledreux, A..

3 recordsLinked to original sources

bioRxiv2026

Trisomy 21 cerebral organoids exhibit Alzheimer's disease amyloid and apolipoprotein E co-pathologies

Adults with Down syndrome (DS) develop Alzheimers disease (AD) brain pathology by age 40 due to triplication of the Amyloid Precursor Protein (APP) gene on chromosome 21. Inheritance of the apolipoprotein E-e4 (APOE4) allele of the APOE gene on chromosome 19 remains the greatest genetic risk factor for AD in the typical population, yet its role in DS-associated AD (DS-AD) neuropathogenesis in people with DS is unclear. We generated human induced pluripotent stem cell (hiPSC)-derived neurons, astrocytes, and cerebral organoids (COs) using cells from people with DS and from euploid individuals. Aged DS COs were smaller than aged euploid COs and showed robust amyloid-{beta} neuropathology that was positively correlated with the levels of apoE expression. We then captured extracellular vesicles (EVs) from the conditioned media of COs and observed a decrease in the levels of secreted AD-related proteins, including amyloid, contained within the EVs and in the media from which the EVs were isolated. We also identified distinct neuronal and astrocytic gene expression signatures in DS COs relative to euploid COs, including a set of genes known to interact with both APOE and APP at the gene and/or protein levels. Lastly, we determined that, despite differences in the expression levels of the specific genes involved, several common pathways were upregulated in T21 hiPSC-derived neurons, astrocytes, and COs, including apoptosis, the endolysosome, and structural stabilization pathways. Taken together, our findings provide novel insights into molecular mechanisms that may contribute to DS-AD and indicate that apoE plays an important role in the disease process.

neuroscience↗

bioRxiv2023

Assessment of brain-derived extracellular vesicle enrichment for blood biomarker analysis in age-related neurodegenerative diseases: An international overview

INTRODUCTIONBrain-derived extracellular vesicles (BEVs) in blood allows for minimally- invasive investigations of CNS-specific markers of age-related neurodegenerative diseases (NDDs). Polymer-based EV- and immunoprecipitation (IP)-based BEV-enrichment protocols from blood have gained popularity. We systematically investigated protocol consistency across studies, and determined CNS-specificity of proteins associated with these protocols. METHODSNDD articles investigating BEVs in blood using polymer-based and/or IP-based BEV enrichment protocols were systematically identified, and protocols compared. Proteins used for BEV-enrichment and/or post-enrichment were assessed for CNS- and brain-cell-type- specificity; extracellular domains (ECD+); and presence in EV-databases. RESULTS82.1% of studies used polymer-based (ExoQuick) EV-enrichment, and 92.3% used L1CAM for IP-based BEV-enrichment. Centrifugation times differed across studies. 26.8% of 82 proteins systematically identified were CNS-specific: 50% ECD+, 77.3% were listed in EV- databases. DISCUSSIONWe identified protocol steps requiring standardization, and recommend additional CNS-specific proteins that can be used for BEV-enrichment or as BEV-biomarkers.

neuroscience↗

bioRxiv2021

Foldamers Reveal and Validate Novel Therapeutic Targets Associated with Toxic α-Synuclein Self-Assembly

Parkinsons disease (PD) is a progressive neurodegenerative disorder for which there is no successful prevention or intervention. The pathological hallmark for PD involves the self-assembly of functional Alpha-Synuclein (S) into non-functional amyloid structures. One of the potential therapeutic interventions against PD is the effective inhibition of S aggregation. However, the bottleneck towards achieving this goal is the identification of S domains/sequences that are essential for aggregation. Using a protein mimetic approach, we have identified S sequences-based novel targets that are essential for aggregation and will have significant therapeutic implications. An extensive array of in vitro, ex vivo, and in vivo assays was utilized to validate S sequences and their structural characteristics that are essential for aggregation and propagation of PD phenotypes. The study aids in developing significant mechanistic and therapeutic insights into various facets of S aggregation, which will pave the way for novel and effective treatments for PD.

biochemistry↗