Scalability of spheroid-derived small extracellular vesicles production in stirred systems

IntroductionSmall extracellular vesicle (sEV)-based therapies have gained widespread interest, but challenges persist to ensure standardization and high-scale production. Implementing upstream processes in a chemically defined media in stirred-tank bioreactors (STBr) is mandatory to closely control the cell environment, and to scale-up production, but it remains a significant challenge for anchorage-dependent cells.MethodsWe used a human β cell line, grown as monolayer or in suspension as spheroid in stirred systems. We assessed the consequences of culturing these cells in 3D with, or without fetal bovine serum in a chemically defined medium, for cell growth, viability and metabolism. We next explored how different scale-up strategies might influence cell and spheroid formation in spinner flask, with the aim to transfer the process in instrumented Ambr®250 STBr. Lastly, we analyzed and characterized sEV production in monolayer, spinner flask and STBr.Results and discussionGeneration of spheroids in a chemically defined medium allowed the culture of highly viable cells in suspension in stirred systems. Spheroid size depended on the system’s volumetric power input (P/V), and maintaining this parameter constant during scale-up proved to be the optimal strategy for standardizing the process. However, transferring the spinner flask (SpF) process to the Ambr®250 STBr at constant P/V modified spheroid size, due to important geometric differences and impeller design. Compared to a monolayer reference process, sEV yield decreased two-fold in SpF, but increased two-fold in STBr. Additionally, a lower expression of the CD63 tetraspanin was observed in sEV produced in both stirred systems, suggesting a reduced release of exosomes compared to ectosomes. This study addresses the main issues encountered in spheroid culture scale-up in stirred systems, rather conducive for the production of ectosomes

Oligodendroglial Epigenetics, from Lineage Specification to Activity-Dependent Myelination

Oligodendroglial cells are the myelinating cells of the central nervous system. While myelination is crucial to axonal activity and conduction, oligodendrocyte progenitor cells and oligodendrocytes have also been shown to be essential for neuronal support and metabolism. Thus, a tight regulation of oligodendroglial cell specification, proliferation, and myelination is required for correct neuronal connectivity and function. Here, we review the role of epigenetic modifications in oligodendroglial lineage cells. First, we briefly describe the epigenetic modalities of gene regulation, which are known to have a role in oligodendroglial cells. We then address how epigenetic enzymes and/or marks have been associated with oligodendrocyte progenitor specification, survival and proliferation, differentiation, and finally, myelination. We finally mention how environmental cues, in particular, neuronal signals, are translated into epigenetic modifications, which can directly influence oligodendroglial biology

Oligodendroglial Epigenetics, from Lineage Specification to Activity-Dependent Myelination

Oligodendroglial cells are the myelinating cells of the central nervous system. While myelination is crucial to axonal activity and conduction, oligodendrocyte progenitor cells and oligodendrocytes have also been shown to be essential for neuronal support and metabolism. Thus, a tight regulation of oligodendroglial cell specification, proliferation, and myelination is required for correct neuronal connectivity and function. Here, we review the role of epigenetic modifications in oligodendroglial lineage cells. First, we briefly describe the epigenetic modalities of gene regulation, which are known to have a role in oligodendroglial cells. We then address how epigenetic enzymes and/or marks have been associated with oligodendrocyte progenitor specification, survival and proliferation, differentiation, and finally, myelination. We finally mention how environmental cues, in particular, neuronal signals, are translated into epigenetic modifications, which can directly influence oligodendroglial biology.</jats:p

Correction: Pruvost, M.; Moyon, S. Oligodendroglial Epigenetics, from Lineage Specification to Activity-Dependent Myelination. <i>Life</i> 2021, <i>11</i>, 62

The authors wish to make the following corrections to this paper [...

DUTTLENHEIM Vier AeckernA 355 – Contournement Ouest de StrasbourgSite 1.1

À quelques kilomètres au sud-ouest de l’agglomération strasbourgeoise, la commune de Duttlenheim se situe sur le horst de Griesheim-Gloeckelsberg, qui borde au sud le plateau du Kochersberg. La zone de fouille est localisée au sud-est du village actuel, au lieu-dit Vier Aeckern.Portant sur une surface de 914 m², la fouille a permis la découverte de sept structures dont quatre sont des fosses contemporaines de type «fosses à betterave».L’essentiel des résultats de cette opération concerne donc la mise au jour d’un petit ensemble funéraire attribué au Bronze ancien, repéré dès l’opération de diagnostic, constitué de trois sépultures. Deux d’entre elles présentent toutes les caractéristiques désormais classiques de la pratique funéraire du Bronze ancien régional, bien que l’une d’entre elles ait livré des éléments de mobilier associé au défunt, ce qui est encore assez peu fréquent en Alsace.Située au centre de ce petit groupe, la troisième, dont l’attribution au Bronze ancien est confirmée par une datation 14C, possède quant à elle des caractères plus atypiques. Les restes osseux qu’elle contenait, appartenant vraisemblablement à un même individu, ont en effet été mis au jour sur deux niveaux et l’on a pu constater l’absence de la plupart des éléments de grandes dimensions du squelette. Associant l’ensemble des données de lafouille, l’étude détaillée de cette sépulture suggère qu’il pourrait s’agir là des traces laissées par une réintervention anthropique de type « pillage », phénomène rarement évoqué pour cette période

ADAMTS proteoglycanases in the physiological and pathological central nervous system.

International audience: ADAMTS-1, -4, -5 and -9 belong to 'a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)' family and more precisely to the proteoglycanases subgroup based on their common ability to degrade chondroitin sulfate proteoglycans. They have been extensively investigated for their involvement in inflammation-induced osteoarthritis, and a growing body of evidence indicates that they may be of key importance in the physiological and pathological central nervous system (CNS). In this review, we discuss the deregulated expression of ADAMTS proteoglycanases during acute CNS injuries, such as stroke and spinal cord injury. Then, we provide new insights on ADAMTS proteoglycanases mediating synaptic plasticity, neurorepair, angiogenesis and inflammation mechanisms. Altogether, this review allows us to propose that ADAMTS proteoglycanases may be original therapeutic targets for CNS injuries

Microglia clear neuron-released α-synuclein via selective autophagy and prevent neurodegeneration

AbstractMicroglia maintain brain homeostasis by removing neuron-derived components such as myelin and cell debris. The evidence linking microglia to neurodegenerative diseases is growing; however, the precise mechanisms remain poorly understood. Herein, we report a neuroprotective role for microglia in the clearance of neuron-released α-synuclein. Neuronal α-synuclein activates microglia, which in turn engulf α-synuclein into autophagosomes for degradation via selective autophagy (termed synucleinphagy). Synucleinphagy requires the presence of microglial Toll-like receptor 4 (TLR4), which induces transcriptional upregulation of p62/SQSTM1 through the NF-κB signaling pathway. Induction of p62, an autophagy receptor, is necessary for the formation of α-synuclein/ubiquitin-positive puncta that are degraded by autophagy. Finally, disruption of microglial autophagy in mice expressing human α-synuclein promotes the accumulation of misfolded α-synuclein and causes midbrain dopaminergic neuron degeneration. Our study thus identifies a neuroprotective function of microglia in the clearance of α-synuclein via TLR4-NF-κB-p62 mediated synucleinphagy.</jats:p