Biology subjects

Benaliouad, F.

Publications and source records attributed to Benaliouad, F..

4 recordsLinked to original sources

bioRxiv2026

Microbiota-derived extracellular vesicles link intestinal dysbiosis to neuroimmune activation in long COVID

Post COVID-19 condition (Long COVID, LC) is frequently accompanied by persistent neurological symptoms, but the mechanisms linking intestinal dysbiosis to neuroinflammation remain unclear. Here we identify gut microbiota-derived extracellular vesicles (GMEVs) as functional mediators linking LC-associated dysbiosis to systemic and neuroimmune inflammation. In a longitudinally characterized cohort, individuals with LC and neurological symptoms exhibit a persistent intestinal microbiome signature. Transplantation of LC-associated microbiota into germ-free mice induces intestinal barrier disruption and neuroinflammatory phenotypes. GMEVs from individuals with LC activate inflammasome-associated programs and impair epithelial barrier function, promote inflammatory responses in macrophages, and induce coordinated pro-inflammatory transcriptional programs in human induced pluripotent stem cell (iPSC)-derived microglia. Chronic oral administration of LC-derived GMEVs remodels the microbiota and induces intestinal and systemic inflammation with glial activation in vivo. Together, these findings support a vesicle-centered framework in which microbiota-derived extracellular vesicles translate dysbiosis into sustained immune and neuroimmune activation in a post-viral inflammatory state.

microbiology↗

bioRxiv2025

An automated workflow for quantifying the formation of synuclein aggregates in human dopaminergic neurons

Parkinsons disease (PD) is a neurodegenerative disorder characterized by alpha-synuclein (-syn) aggregates termed Lewy bodies. To model PD pathology in vitro, preformed fibrils of -syn (PFFs), which can be taken up by cells, provide a seed that drives misfolding and aggregation of endogenous -syn, with new aggregates amplifying this process. External application of PFFs to dopaminergic neurons (DNs) increases aggregate formation, marked by -syn phosphorylation at serine 129 (pS129-syn), a pathological PD marker. Building on this, we developed an automated synuclein seeding assay to quantify new -syn aggregates in iPSC-derived DNs. Using pS129-syn as a readout, we show that PFFs elicit a time- and dose-dependent increase in pS129-syn aggregates. Our high-throughput assay further revealed that aggregate formation depends on endogenous -syn levels. Treatment with PFFs produced a greater increase in pS129-syn aggregates in iPSC DNs derived from a PD patient with a triplication in the SNCA gene, which encodes the -syn protein and which elevates total -syn levels, relative to DNs from an isogenic iPSC line from the same individual, in which the SNCA gene mutation had been corrected by CRISPR/Cas9. In contrast, no pS129-syn signal was detected in neurons in which all copies of the SNCA gene had been knocked out (KO). This high-content imaging assay for synuclein seeding offers a platform for assessing compounds and therapeutics that may impede -syn aggregate formation.

neuroscience↗

bioRxiv2020

Dopamine D1 receptor signalling in dyskinetic Parkinsonian rats revealed by fiber photometry using FRET-based biosensors

Like many G protein-coupled receptors (GPCRs), the signalling pathways regulated by the dopamine D1 receptor (D1R) are dynamic, cell-type specific, and can change in response to disease or drug exposures. In striatal neurons, the D1R activates cAMP/protein kinase A (PKA) signalling. However, in Parkinsons disease (PD), alterations in this pathway lead to activation of extracellular regulated kinases (ERK1/2), contributing to L-DOPA-induced dyskinesia (LID). In order to detect D1R activation in vivo and to study the progressive dysregulation of D1R signalling in PD and LID, we developed ratiometric fiber-photometry with Forster resonance energy transfer (FRET) biosensors and optically detected PKA and ERK1/2 signalling in freely moving rats. We show that in Parkinsonian animals, D1R signalling through PKA and ERK1/2 is sensitized, but that following chronic treatment with L-DOPA, these pathways become partially desensitized while concurrently D1R activation leads to greater induction of dyskinesia.

neuroscience↗

bioRxiv2018

Implementation of an antibody characterization process: Application to the major ALS/FTD disease gene C9ORF72

Rigorously characterized antibodies are a key resource in biomedical research, yet there are no community-accepted processes to characterize the quality of research grade antibodies. This has led to a proliferation of poorly characterized antibodies of suspect quality, which in turn has led to flaws in the literature that hamper research progress, including the study of human disease. We selected the human protein C9ORF72 as a test case to implement a more standardized antibody characterization process. Mutations in the gene C9ORF72 are the major genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia but much remains unknown regarding the function of the encoded protein. We used CRISPR/Cas9-based knockout cells and knockout mice as controls to characterize 14 C9ORF72 antibodies including 12 commercially available antibodies advertised as selective for C9ORF72. We found one monoclonal antibody that is specific for the protein in immunoblot and that also recognizes C9ORF72 specifically in immunohistochemical applications on brain sections. A second C9ORF72 monoclonal antibody is effective for immunoprecipitation and immunofluorescence. Some of the antibodies that do not recognize C9ORF72 have been used in highly cited papers, raising concern over conclusions regarding previously reported C9ORF72 properties.

molecular biology↗