Trudel, S. | Search bioRxiv

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↗

bioRxiv2021

Single-cell transcriptional analysis of the immune tumour microenvironment during myeloma disease evolution

Multiple myeloma is universally preceded by a premalignant disease state. However, efforts to develop preventative therapeutic strategies are hindered by an incomplete understanding of the immune mechanisms associated with progression. Using single-cell RNA-sequencing, we profiled 104,880 cells derived from the bone marrow of V{kappa}*MYC mice across the myeloma progression spectrum, of which 97,720 were identified as non-malignant cells of the tumour microenvironment. Analysis of the non-malignant cells comprising the immune microenvironment identified mechanisms associated with disease progression in innate and adaptive immune cell populations. This included activation of IL-17 signaling in myeloid cells from precursor mice, accompanied by upregulation of Il6 gene expression in basophils. In the T/Natural killer cell compartment, we identified Tox-expressing CD8+ T cells enriched in the tumour microenvironment of mice with overt disease, with co-expression of LAG3 and PD-1, as well as elevated T cell exhaustion signatures in mice with early disease. We subsequently showed that early intervention with combinatorial blockade of LAG3 and PD-1 using neutralizing monoclonal antibodies delayed tumor progression and improved survival of V{kappa}*MYC mice. Together, this work provides insight into the biology of myeloma evolution and nominates a treatment strategy for early disease.

cancer biology↗