Biology subjects

Ausseil, J.

Publications and source records attributed to Ausseil, J..

3 recordsLinked to original sources

bioRxiv2024

Extracellular vesicles from mucopolysaccharidosis type III microglia impair neurite growth

BackgroundIn mucopolysaccharidosis type III (MPS III), a pediatric neurodegenerative disorder, accumulation of abnormal glycosaminoglycans (GAGs) induces severe neuroinflammation by triggering the microglial pro-inflammatory cytokines production via a TLR4-dependent pathway. But the extent of the microglia contribution to the MPS III neuropathology remains unclear. Extracellular vesicles (EVs) mediate intercellular communication and are known to participate in the pathogenesis of adult neurodegenerative diseases. However, characterization of the molecular profiles of EVs released by MPS III microglia and their effects on neuronal functions have not been described. MethodsHere, we isolated EVs secreted by the microglial cells after treatment with GAGs purified from urines of MPS III patients (MPS III-EVs) to explore the EVs proteins and small RNA profiles using LC-MS/MS and RNA sequencing. We next performed a functional assay by immunofluorescence following wild-type (WT) or MPS III-EVs uptake by WT primary cortical neurons and analyzed their extensions metrics after staining of {beta}III-tubulin and MAP2 by confocal microscopy. ResultsFunctional enrichment analysis for both proteomics and RNA sequencing data from MPS III-EVs revealed a specific content involved in neuroinflammation and neurodevelopment pathways. Treatment of cortical neurons with MPS III-EVs induced a disease-associated phenotype demonstrated by a lower total neurite surface area, an impaired somatodendritic compartment, and a higher number of immature dendritic spines. ConclusionsThis study shows, for the first time, that GAGs from patients with MPS III can induce microglial secretion of EVs that deliver a specific molecular message to recipient naive neurons, while promoting the neuroinflammation, and depriving neurons of neurodevelopmental factors. This work provides a framework for further studies of biomarkers to evaluate efficiency of emerging therapies. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=117 SRC="FIGDIR/small/595318v2_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@8dfd3org.highwire.dtl.DTLVardef@9ece15org.highwire.dtl.DTLVardef@1ebc91eorg.highwire.dtl.DTLVardef@e10b00_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2024

Secondary deficiency of neuraminidase 1 contributes to CNS pathology in neurological mucopolysaccharidoses via hypersialylation of brain glycoproteins

Mucopolysaccharidoses (MPS) are lysosomal storage diseases caused by defects in catabolism of glycosaminoglycans. MPS I, II, III and VII are associated with lysosomal accumulation of heparan sulphate and manifest with neurological deterioration. Most of these neurological MPS currently lack effective treatments. Here, we report that, compared to controls, neuraminidase 1 (NEU1) activity is drastically reduced in brain tissues of neurological MPS patients and in mouse models of MPS I, II, IIIA, IIIB and IIIC, but not of other neurological lysosomal disorders not presenting with heparan sulphate storage. We further show that accumulated heparan sulphate disrupts the lysosomal multienzyme complex of NEU1 with cathepsin A (CTSA), {beta}-galactosidase (GLB1) and glucosamine-6-sulfate sulfatase (GALNS) necessary to maintain enzyme activity, and that NEU1 deficiency is linked to partial deficiencies of GLB1 and GALNS in cortical tissues and iPSC-derived cortical neurons of neurological MPS patients. Increased sialylation of N-linked glycans in brain samples of human MPS III patients and MPS IIIC mice implicated insufficient processing of brain N-linked sialylated glycans, except for polysialic acid, which was reduced in the brains of MPS IIIC mice. Correction of NEU1 activity in MPS IIIC mice by lentiviral gene transfer ameliorated previously identified hallmarks of the disease, including memory impairment, behavioural traits, and reduced levels of the excitatory synapse markers VGLUT1 and PSD95. Overexpression of NEU1 also restored levels of VGLUT1-/PSD95-positive puncta in cortical neurons derived from iPSC of an MPS IIIA patient. Together, our data demonstrate that heparan sulphate-induced secondary NEU1 deficiency and aberrant sialylation of glycoproteins implicated in synaptogenesis, memory, and behaviour constitute a novel pathological pathway in neurological MPS spectrum crucially contributing to CNS pathology. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=89 SRC="FIGDIR/small/587986v1_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@3905c3org.highwire.dtl.DTLVardef@1a9672corg.highwire.dtl.DTLVardef@b4911forg.highwire.dtl.DTLVardef@a3b190_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2020

Consequences of human cytomegalovirus infection on small extracellular vesicles isolated from first trimester placental histocultures

Currently, research on the use of non-invasive biomarkers as diagnosis and prognosis tools during pathological pregnancies is in full development. Among these, placenta-derived small extracellular vesicles (sEVs) are considered as serious candidates, since their composition is modified during many pregnancy pathologies. Moreover, sEVs are found in maternal serum and can thus be easily purified from a simple blood sample. In this study, we describe the isolation of sEVs from a histoculture model of first trimester placental explants. Using bead-based multiplex cytometry and electron microscopy combined with biochemical approaches, we characterized these sEVs and defined their associated markers and ultrastructure. We next examined the consequences of infection by human cytomegalovirus on sEVs secretion and characteristics. We observed that infection led to increased levels of expression of several surface markers, without any impact on the secretion and integrity of sEVs. Our findings open the prospect for the identification of new predictive biomarkers for the severity and outcome of this congenital infection early during pregnancy, which are still sorely lacking.

cell biology↗