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Rationale: Synucleinopathies, including Parkinson's disease (PD), multiple system atrophy (MSA), and dementia with Lewy bodies (DLB), share a distinct pathological feature, that is, a widespread accumulation of α‐synuclein (α‐syn) in the brain. There is a significant clinical unmet need for disease‐modifying treatments for synucleinopathies. Recently, a seaweed‐derived mixture of oligosaccharides sodium oligomannate, GV‐971, was approved for Phase 2 clinical trials for PD. This study aimed to further evaluate the therapeutic effects of GV‐971 on synucleinopathies using cellular and animal models and explore its associated molecular mechanisms. Methods: α‐Syn aggregation was assessed, in vitro and ex vivo, by ThT assay. A dopaminergic neuron cell line, Prnp‐SNCAA53T mice, and brain slices from PD and DLB patients were used to determine the efficacy of GV‐971 in ameliorating α‐syn pathology. Measurements of motor functions, including pole, cylinder, and rotarod tests, were conducted on Prnp‐SNCAA53T mice 4 weeks after intragastric administration of GV‐971 (200 mg day−1 kg−1). Results: GV‐971 effectively prevented α‐syn aggregation and even disassembled pre‐aggregated α‐syn fibrils, in vitro and ex vivo. In addition, GV‐971 was able to rescue α‐syn‐induced neuronal damage and reduced release of extracellular vesicles (EVs), likely via modulating Alix expression. In the Prnp‐SNCAA53T mouse model, when treated at the age of 5 months, GV‐971 significantly decreased α‐syn deposition in the cortex, midbrain, and cerebellum regions, along with ameliorating the motor dysfunctions. Conclusions: Our results indicate that GV‐971, when administered at a relatively early stage of the disease process, significantly reduced α‐syn accumulation and aggregation in Prnp‐SNCAA53T mice. Furthermore, GV‐971 corrected α‐syn‐induced inhibition of EVs release in neurons, contributing to neuronal protection. Future studies are needed to further assess GV‐971 as a promising disease‐modifying therapy for PD and other synucleinopathies. [ABSTRACT FROM AUTHOR]

Background: Progressive spreading of α‐synuclein via gut‐brain axis has been hypothesized in the pathogenesis of Parkinson's disease (PD). However, the source of seeding‐capable α‐synuclein in the gastrointestinal tract (GIT) has not been fully investigated. Additionally, the mechanism by which the GIT microbiome contributes to PD pathogenesis remains to be characterized. Objectives: We aimed to investigate whether blood‐derived α‐synuclein might contribute to PD pathology via a gut‐driven pathway and involve GIT microbiota. Methods: The GIT expression of α‐synuclein and the transmission of extracellular vesicles (EVs) derived from erythrocytes/red blood cells (RBCs), with their cargo α‐synuclein, to the GIT were explored with various methods, including radioactive labeling of RBC‐EVs and direct analysis of the transfer of α‐synuclein protein. The potential role of microbiota on the EVs transmission was further investigated by administering butyrate, the short‐chain fatty acids produced by gut microbiota and studying mice with different α‐synuclein genotypes. Results: This study demonstrated that RBC‐EVs can effectively transport α‐synuclein to the GIT in a region‐dependent manner, along with variations closely associated with regional differences in the expression of gut‐vascular barrier markers. The investigation further revealed that the infiltration of α‐synuclein into the GIT was influenced significantly by butyrate and α‐synuclein genotypes, which may also affect the GIT microbiome directly. Conclusion: By demonstrating the transportation of α‐synuclein through RBC‐EVs to the GIT, and its potential association with gut‐vascular barrier markers and gut microbiome, this work highlights a potential mechanism by which RBC α‐synuclein may impact PD initiation and/or progression. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

Objective: Accumulation of α‐synuclein (α‐syn) in neurons is a prominent feature of Parkinson's disease (PD). Recently, researchers have considered that extracellular vesicles (EVs) may play an important role in protein exportation and propagation, and α‐syn‐containing EVs derived from the central nervous system (CNS) have been detected in peripheral blood. However, mechanistic insights into CNS‐derived EVs have not been well‐described. Methods: Likely neurogenic EVs were purified from the plasma of PD patients and healthy controls using a well‐established immunoprecipitation assay with anti‐L1CAM‐coated beads. A Prnp‐SNCAA53T transgenic PD mouse model was used to evaluate the neuronal pathology induced by PD‐derived L1CAM‐purified EVs. EV‐associated microRNA (miRNA) profiling was used to screen for altered miRNAs in PD‐derived L1CAM‐purified EVs. Results: PD patient‐derived L1CAM‐purified (likely neurogenic) EVs facilitated α‐syn pathology and neuron loss in Prnp‐SNCAA53T transgenic PD mice. The miRNA, novel_miR_44438, was significantly increased in the PD group, which promoted α‐syn accumulation and neuronal degeneration in a dose‐dependent manner. Novel _miR_44438 directly targets NDST1 mRNA and inhibits the function of heparan sulfate, thus preventing exosome biogenesis and α‐syn release from exosomes. Interpretation: Novel_miR_44438 in PD‐derived L1CAM‐purified EVs inhibits the α‐syn efflux from neurons thereby promoting the pathological accumulation and aggregation of α‐syn. ANN NEUROL 2022;92:230–245 [ABSTRACT FROM AUTHOR]

Wilms tumor (WT) is the most common renal cancer and the most prevalent abdominal cancer in children. Children with recurrent or progressive forms of WT could benefit from novel immune-targeted approaches. While the immune status of these patients, especially the immunosuppression of peripheral T cells, was rarely reported. The present study enrolled a consecutive series of 14 Chinese WT children and 14 age- and gender-matched healthy controls. We demonstrated that plasma extracellular vesicular (EV) PD-L1 levels significantly increased in WT patients than in healthy controls. EV PD-L1 significantly inhibited the activation of human CD8+ T cells by down-regulating the cell surface CD69 expression and the intracellular IFNγ and TNFα production in vitro. In peripheral CD8+ T cells of WT patients, the intracellular IFNγ and TNFα production significantly decreased than healthy controls. The level of plasma EV PD-L1 significantly correlated with the intracellular TNFα production in peripheral CD8+ T cells of WT patients. In conclusion, the significantly increased plasma EV PD-L1 in WT patients contributed to the immunosuppression of peripheral CD8+ T cells. Monitoring the level of plasma EV PD-L1 will be helpful for the selection of immune-targeted therapies for WT patients. [ABSTRACT FROM AUTHOR]

Medulloblastoma (MB), the most common malignant pediatric brain tumor, is composed of at least four molecular subgroups with distinct clinical characteristics. The sonic hedgehog (SHH) subgroup exhibits the most abundant tumor-associated microglia/macrophages (TAMs) infiltration. SHH-MB patients treated by anti-SHH drugs showed high drug resistance. However, the comprehensive role of TAMs in SHH-MB remains enigma. The aim of this study is to explore the mechanism of TAM activation/polarization in SHH-MB and discover a potential immunotherapeutic target to reduce drug resistance. We first analyzed expression profiles of immuno-microenvironment (IME) in four subgroups of 48 MB tumors using NanoString PanCancer IO360 panel and found TAMs were the major component of IME in SHH-MBs. We further distinguished M1/M2-like TAMs in tumors and found M2-like macrophages, rather than microglia, were enriched in SHH-MBs. In transgenic SHH-MB mice, these TAMs had close relationship with tumor progression. Polarization of the TAMs could be induced by MB-derived exosomes in vitro. We then screened SHH MB-derived exosomal miRNAs and their target genes using RNA sequencing and luciferase assay to clarify their roles in regulating TAM polarization. We found down-regulated let-7i-5p and miR-221-3p can induce M2-like polarization of TAMs via upregulating peroxisome proliferator activated receptor gamma (PPARγ). Finally, we demonstrated the PPARγ antagonist efficiently improved the antitumor activity of SMO inhibitor in vivo, which may be related to inhibition of M2-like TAMs. Our findings suggest a potential therapeutic strategy for SHH-MB by targeting tumor-supportive M2-like TAMs to enhance the therapeutic effect of SMO inhibitors. [ABSTRACT FROM AUTHOR]

Biological functions of extracellular vesicles (EVs) are being discovered to be critical in neurodegenerative disorders, including Parkinson's disease (PD). A previous study using cellular models of PD has suggested that EVs derived from microglia exposed to aggregated α-synuclein (α-Syn) leads to enhanced neurotoxicity. However, the function of EVs derived from microglia not treated with aggregated a-Syn or treated with monomeric α-Syn are unclear. Here, employing a widely used cellular model of PD, i.e. SH-SY5Y cells treated with MPP + , a well-established parkinsonian toxicant, we revealed that microglial EVs, when not stimulated by aggregated α-Syn, appeared to be protective, and the mechanisms, though remain to be defined further, appeared to involve mitochondrial dynamics, especially mitochondrial fission., (Copyright © 2019 Elsevier Inc. All rights reserved.)