Astrocytes reassessment - an evolving concept part one: embryology, biology, morphology and reactivity

Şovrea, Alina Simona; Boșca, Adina Bianca

doi:10.1186/2049-9256-1-18

Cited by 18 publications

(12 citation statements)

References 88 publications

(128 reference statements)

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“…The cell bodies span over 10 mm in some regions and processes up to 90 mm. This may account for an increase in volume than in the laboratory rodent suggesting that density alone does not account for astrocytic function but synaptic volume ( Şovrea and Boşca, 2013 ). That age groups present increasing number of astrocytic populations indicates that the functional significance of astrocytes will progressively increase from neonates to juvenile and subsequently be reduced in the adults.…”

Section: Discussionmentioning

confidence: 99%

Astrocyte morphology, heterogeneity, and density in the developing African giant rat (Cricetomys gambianus)

et al. 2015

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Astrocyte morphologies and heterogeneity were described in male African giant rats (AGR; Cricetomys gambianus, Waterhouse) across three age groups (five neonates, five juveniles, and five adults) using Silver impregnation method and immunohistochemistry against glial fibrillary acidic protein. Immunopositive cell signaling, cell size and population were least in neonates, followed by adults and juveniles, respectively. In neonates, astrocyte processes were mostly detected within the glia limitans of the mid and hind brain; their cell bodies measuring 32 ± 4.8 μm in diameter against 91 ± 5.4 μm and 75 ± 1.9 μm in juveniles and adults, respectively. Astrocyte heterogeneity in juvenile and adult groups revealed eight subtypes to include fibrous astrocytes chiefly in the corpus callosum and brain stem, protoplasmic astrocytes in the cortex and dentate gyrus (DG); radial glia were found along the olfactory bulb (OB) and subventricular zone (SVZ); velate astrocytes were mainly found in the cerebellum and hippocampus; marginal astrocytes close to the pia mater; Bergmann glia in the molecular layer of the cerebellum; perivascular and periventricular astrocytes in the cortex and third ventricle, respectively. Cell counts from twelve anatomical regions of the brain were significantly higher in juveniles than in adults (p ≤ 0.01) using unpaired student t-test in the cerebral cortex, pia, corpus callosum, rostral migratory stream, DG, and cerebellum. Highest astrocyte count was found in the DG, while the least count was in the brain stem and sub cortex. Astrocytes along the periventricular layer of the OB are believed to be part of the radial glia system that transport newly formed cells towards the hippocampus and play roles in neurogenesis migration and homeostasis in the AGR. Therefore, astrocyte heterogeneity was examined across age groups in the AGR to determine whether age influences astrocytes population in different regions of the AGR brain and discuss possible functional roles.

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Section: Discussionmentioning

confidence: 99%

Astrocyte morphology, heterogeneity, and density in the developing African giant rat (Cricetomys gambianus)

et al. 2015

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“…Astrocyte reaction to certain stimuli is defined by a wide range of heterogeneous responses, including changes in morphology [7,46]. To analyse the effect of oxysterols on astrocyte morphology and survival, cells were exposed to increasing concentrations of the Early and Late mixtures (1, 5 or 10 µM).…”

Section: Oxysterol Mixtures Induce a Morphological Change In Astrocytesmentioning

confidence: 99%

Oxysterols Present in Alzheimer’s Disease Braininduce Synaptoxicity by Activating Astrocytes: A Major Role for Lipocalin-2

Staurenghi

Cerrato

Gamba

et al. 2020

Preprint

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Background: Among Alzheimer’s disease (AD) brain hallmarks, the presence of reactive astrocytes was demonstrated to correlate with neuronal loss and cognitive deficits. Evidence indeed supports the role of reactive astrocytes as mediators of changes in neurons, including synapses. However, the complexity and the outcomes of astrocyte reactivity are far from being completely elucidated. Another key role in AD pathogenesis is played by alterations in brain cholesterol metabolism. Oxysterols (cholesterol oxidation products) are crucial for brain cholesterol homeostasis, and we previously demonstrated that changes in the brain levels of various oxysterols correlate with AD progression. Moreover, oxysterols have been shown to contribute to various pathological mechanisms involved in AD pathogenesis.In order to deepen the role of oxysterols in AD, we investigated whether they could contribute to astrocyte reactivity, and consequently impact on neuronal health.Methods: Mouse primary astrocyte cultures were used to test the effect of two oxysterol mixtures, that represent the oxysterol composition respectively of mild or severe AD brains, on astrocyte morphology, markers of reactivity, and secretion profile. Co-culture experiments were performed to investigate the impact of oxysterol-treated astrocytes on neurons. Neuronal cultures were exposed to astrocyte conditioned media (ACM) deprived of lipocalin-2 (Lcn2) to investigate the contribution of this mediator to synaptotoxicity.Results: Results showed that oxysterols induce a clear morphological change in astrocytes, accompanied by the upregulation of some reactive astrocyte markers, including Lcn2. Moreover, ACM analysis revealed a significant increase in the release of Lcn2, cytokines, and chemokines in response to oxysterols. A significant reduction of postsynaptic density protein 95 (PSD95) and a concurrent increase in cleaved caspase-3 protein levels have been demonstrated in neurons co-cultured with oxysterol-treated astrocytes, pointing out that mediators released by astrocytes have an impact on neurons. Among these mediators, Lcn2 has been demonstrated to play a major role on synapses, affecting neurite morphology and decreasing dendritic spine density. Conclusions: These data demonstrated that oxysterols present in the AD brain promote astrocyte reactivity, determining the release of several mediators that affect neuronal health and synapses. Lcn2 has been shown to exert a key role in mediating the synaptotoxic effect of oxysterol-treated astrocytes.

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“…Müller cells in the retina, Bergman glia and protoplasmic velate astrocytes in the cerebellum are yet another example of glia diversity (111). There are also astrocytes specific to primates and humans including interlaminar and varicose projection astrocytes (36,(112)(113)(114). In addition, characterized by their GFAP and glycogen granules, adult astrocytes in the SVZ, namely type-B1 and -B2 cells, are a tripotent stem cell population having the potential to generate neurons, astrocytes and oligodendrocytes (115).…”

Section: Astrocyte Biologymentioning

confidence: 99%

Plasminogen binding inhibitors demonstrate unwanted activities on GABA A and glycine receptors in human iPSC derived neurons

Kristensson

Lundin

Gustafsson³

et al. 2018

Neuroscience Letters

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Astrocytes reassessment - an evolving concept part one: embryology, biology, morphology and reactivity

Cited by 18 publications

References 88 publications

Astrocyte morphology, heterogeneity, and density in the developing African giant rat (Cricetomys gambianus)

Astrocyte morphology, heterogeneity, and density in the developing African giant rat (Cricetomys gambianus)

Oxysterols Present in Alzheimer’s Disease Braininduce Synaptoxicity by Activating Astrocytes: A Major Role for Lipocalin-2

Plasminogen binding inhibitors demonstrate unwanted activities on GABA A and glycine receptors in human iPSC derived neurons

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