Biology subjects

Jeannelle, F.

Publications and source records attributed to Jeannelle, F..

3 recordsLinked to original sources

bioRxiv2026

Disease-specific tangle immunophenotypes distinguish hippocampal vulnerability in Alzheimers disease and Parkinsons disease dementia

Structured AbstractINTRODUCTION Tau pathology typically occurs in Alzheime[r]s disease (AD), however is also frequently present in Parkinso[n]s disease dementia (PDD) and Dementia with Lewy Bodies (DLB), yet its disease-specific signature is unclear. METHODSFive tau, amyloid-{beta}, -synuclein and neuronal markers were analysed across hippocampal subfields in non-demented controls (CTLs), AD, PDD and DLB using multiplex immunohistochemistry, single-tangle classification and confocal imaging. RESULTSAT8, pTau217, and GT38 were predominatly detected in AD, while pS422 was enriched in PDD and pS396 showed a region- and disease-specific pattern. DLB resembled AD in subregional tau distribution. Tau marker correlation were different comparing AD, PDD and CTL. Single-tangle analyses revealed disease-specific immunophenotypes but conserved mature intra-tangle epitope organisation. Distinct tau signatures were associated with inhibitory interneuron vulnerability, while regional tau co-occurrence with amyloid-{beta} and -synuclein remained conserved. DISCUSSIONDisease-specific tau signatures vary across hippocampal subregions and neuronal populations, implicating the contribution of regional and cell-specific factors beyond pathology burden.

neuroscience↗

bioRxiv2025

GPC5 expression highlights astrocytic heterogeneity and divergent hippocampal responses in Alzheimer's and Parkinson's Dementia

Regional heterogeneity of astrocytes and neurons is increasingly recognised as a determinant of selective vulnerability in neurodegeneration, yet the molecular signatures underlying this specificity remain poorly defined. Glypican-5 (GPC5), a heparan sulfate proteoglycan expressed mainly by astrocytes, contributes to synaptic organisation and circuit stability, whose disruption may undermine astrocyte-neuron crosstalk and contribute to selective neuronal loss in neurodegenerative diseases. Using multiplex chromogenic immunohistochemistry, in situ hybridization and digital pathology, we mapped GPC5 expression across the hippocampus and parahippocampal cortex in post-mortem tissue from non-demented control (CTL), Alzheimers disease (AD) and Parkinsons disease with dementia (PDD) cases. In CTL brains, GPC5 labelled spatially restricted populations of astrocytes and pyramidal neurons organized according to hippocampal subfield and laminar architecture. GPC5-positive astrocytes co-expressed canonical markers but represented a more restricted population while GPC5 protein was enriched at synapse-rich regions of the outer molecular layer of the dentate gyrus. In AD and PDD, regional distribution patterns of GPC5 were distinct from canonical astrocyte markers including GFAP, AQP4 and ALDH1L1. In PDD, GPC5 distribution was largely preserved. In AD, GPC5 underwent selective redistribution with a significant loss of the staining in the dentate gyrus, and an accumulation on amyloid plaques, putatively secreted by plaque-associated astrocytes, and on neurofibrillary tangles, likely of neuronal and astrocytic origin These findings reveal disease- and region-specific remodelling of a spatially organised astrocyte-neuron system and establish GPC5 as a molecularly distinct responder to AD pathology.

neuroscience↗

bioRxiv2024

DJ-1 mediates regulation of metabolism and immune response in Parkinsons disease astrocytes and Glioblastoma cells

An inverse correlation for the expression of Parkinsons disease (PD)- and cancer-associated genes has been previously reported. Genes that are upregulated in cancer are frequently downregulated in PD and vice versa. PARK7, encoding DJ-1, was initially identified as an oncogene, but loss of DJ-1 causes early-onset PD. However, it remains elusive how differential DJ-1 levels contribute to opposite cell fates in cancer and PD. Here, we demonstrate specific effects of differential DJ-1 protein levels on the energy metabolism and cell growth in patient-derived cellular models of PD and glioblastoma (GBM) cell lines. Impaired energy metabolism was associated with an increased immune response upon IL-1{beta} stimulation and increased apoptosis and decreased cell growth in models of PD, whereas in GBM cells increased metabolic activity translated into a reduced immune response and increased cell growth. Furthermore, we found decreased glutathione (GSH) synthesis and therefore increased levels of reactive oxygen species (ROS) and oxidized glutathione (GSSG) in models of DJ-1 deficiency and decreased ROS levels in GBM cell lines. Thus, the mechanism by which DJ-1 modulates these phenotypes is the same in both diseases. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=84 SRC="FIGDIR/small/621212v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@4eccb4org.highwire.dtl.DTLVardef@161669corg.highwire.dtl.DTLVardef@197bfc3org.highwire.dtl.DTLVardef@1aecb36_HPS_FORMAT_FIGEXP M_FIG C_FIG DJ-1 levels modulate GSSG/GSH ratio and ROS levels, which results in divergent effects on cell growth and immune response in DJ-1-dependent glial pathologies in glioblastoma and PD. In models of PD, DJ-1 level dependent phenotypes can be rescued by antioxidant treatment that reduces the GSSG/GSH ratio and ROS levels.

neuroscience↗