GLIA Porto 2019: Abstracts Oral Presentations, Posters, Indexes

Abstract

Reversible oxidative modifications regulate protein activity. Oxidoreductases such as Glutaredoxin 2 control the thiol redox state of proteins. Here, we demonstrate that Glutaredoxin 2 modifies the cytoskeleton and thereby migration capacity of glia cells. The lack of Glutaredoxin 2 decreases transmigration of mouse primary oligodendrocyte progenitor cells, whereas enhanced levels of Glutaredoxin 2 increase migration. In both, transmigration and scratch closure Glutaredoxin 2 is able to overcome the inhibitory effect of Semaphorin 3A. We found that Glutaredoxin 2 levels control expression of NG2. Therefore, enhanced levels of Glutaredoxin 2 not only affect migration, but also block differentiation of oligodendrocytes in the NG2-glia state. The importance of Glutaredoxin 2 during migration and differentiation of progenitor cells was confirmed in zebrafish with manipulated Glutaredoxin 2 translation. Since NG2/CSPG4 is associated with metastasis/invasion of cancer cells, we investigated the impact of Glutaredoxin 2 on migration and invasion of glioblastoma cells. Injection of patient derived glioblastoma cells with or without manipulated expression of Glutaredoxin 2 into developing zebrafish embryos revealed that Glutaredoxin 2 is essential for metastasis/invasion of glioblastoma cells. Via the migration of glia cells, our data connect specific redox regulation with physiological and pathological processes during development of the myelin sheeth, tissue regeneration, and glioblastoma invasion. E128 POSTERS GLIA Different types of brain damage induce activation and migration of microglial cells towards injury sites. Deregulated microglial response contributes to the development and propagation of various neurological disorders and therefore targeting of neuroinflammatory microglia is considered as a novel therapeutic strategy. We investigated effects of extracellular vesicles (EVs) derived from human dental pulp stem cells (DPSCs) and recently suggested as promising regenerative tools in neurological disorders, on ATP signalling in human microglial cells. Human immortalized (SV40) microglial cells were cultivated in exosome-depleted medium. EVs were purified by differential ultracentrifugation from DPSCs grown in serum-and xeno-free medium. Migration assays have been performed in Boyden chamber using 8 μm pore membranes. Changes in the intracellular Ca2+ concentration in single cells loaded with Fluo-4 AM were monitored with Till Photonic imaging system. Extracellular ATP concentrations were measured by ATPlite Luminescence Assay System. We found that EVs induced a rapid increase of intracellular Ca2+ in microglial cells and promoted a significant ATP release (by 123 % and 68 % after 20 and 60 min, respectively). EVs increased migration of microglial cells by 20 % whereas ATP degrading enzyme apyrase (20 U/ml) reduced migration by 23%. In apyrase-treated cells, EVs increased migration more efficiently (by 36 %). The nonselective antagonist of ATP-gated P2 receptors suramin (200 µM) decreased cell migration by 21 %. ...

Cerebellar Astrocytes: Much More Than Passive Bystanders In Ataxia Pathophysiology

“…These evidences were indeed very recently confirmed by the development of a transgenic mouse line, in which the mutation was carried by GLAST-expressing astrocytes solely (Slc1a3 P290R/+ mice). This animal model was shown to suffer from epilepsy, ataxia, and showed cerebellar atrophy, thereby closely resembling the features of EA6 [105]. Specifically, these degenerative effects were unveiled to be triggered by an increased chloride efflux from BG, resulting in BG apoptosis and, subsequently, in a secondary loss of glutamate clearance and cerebellar atrophy.…”

Extracellular Vesicles as Nanotherapeutics for Parkinson’s Disease

“…Interestingly, in basal conditions, ventral midbrain astrocytes release more EVs than striatal astrocytes. This diversity in the secretion of EVs seems to suggest the existence of specific brain region-linked differences which may have possible functional implications in the intercellular communication within the nigrostriatal area [254]. Moreover, the authors identified a specific subset of miRNAs and proteins enriched in the ventral midbrain astrocyte-derived EVs, with a potential impact on DAergic neuroprotection and NSC differentiation.…”

“…Remarkably, besides SHED-EVs, glial-derived EVs may play key roles in both neurodegeneration and neuroprotection in PD experimental models, as recently reviewed by our group [51]. For example, the studies of Leggio and collaborators [254] revealed that astrocytes from the ventral midbrain, which induce nigrostriatal rescue in MPTP-treated mice [23], were able to secrete vesicles in the size range of s-EVs and positive for classical EV markers (e.g., CD63, CD9, Tsg101) [254]. Interestingly, in basal conditions, ventral midbrain astrocytes release more EVs than striatal astrocytes.…”