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O'Leary LA, Davoli MA, Belliveau C, Tanti A, Ma JC, Farmer WT, Turecki G, Murai KK, Mechawar N. Characterization of Vimentin-Immunoreactive Astrocytes in the Human Brain. Front Neuroanat 2020; 14:31. [PMID: 32848635 PMCID: PMC7406576 DOI: 10.3389/fnana.2020.00031] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 05/26/2020] [Indexed: 12/19/2022] Open
Abstract
Astrocytes are commonly identified by their expression of the intermediate filament protein glial fibrillary acidic protein (GFAP). GFAP-immunoreactive (GFAP-IR) astrocytes exhibit regional heterogeneity in density and morphology in the mouse brain as well as morphological diversity in the human cortex. However, regional variations in astrocyte distribution and morphology remain to be assessed comprehensively. This was the overarching objective of this postmortem study, which mainly exploited the immunolabeling of vimentin (VIM), an intermediate filament protein expressed by astrocytes and endothelial cells which presents the advantage of more extensively labeling cell structures. We compared the densities of vimentin-immunoreactive (VIM-IR) and GFAP-IR astrocytes in various brain regions (prefrontal and primary visual cortex, caudate nucleus, mediodorsal thalamus) from male individuals having died suddenly in the absence of neurological or psychiatric conditions. The morphometric properties of VIM-IR in these brain regions were also assessed. We found that VIM-IR astrocytes generally express the canonical astrocytic markers Aldh1L1 and GFAP but that VIM-IR astrocytes are less abundant than GFAP-IR astrocytes in all human brain regions, particularly in the thalamus, where VIM-IR cells were nearly absent. About 20% of all VIM-IR astrocytes presented a twin cell morphology, a phenomenon rarely observed for GFAP-IR astrocytes. Furthermore VIM-IR astrocytes in the striatum were often seen to extend numerous parallel processes which seemed to give rise to large VIM-IR fiber bundles projecting over long distances. Moreover, morphometric analyses revealed that VIM-IR astrocytes were more complex than their mouse counterparts in functionally homologous brain regions, as has been previously reported for GFAP-IR astrocytes. Lastly, the density of GFAP-IR astrocytes in gray and white matter were inversely correlated with vascular density, but for VIM-IR astrocytes this was only the case in gray matter, suggesting that gliovascular interactions may especially influence the regional heterogeneity of GFAP-IR astrocytes. Taken together, these findings reveal special features displayed uniquely by human VIM-IR astrocytes and illustrate that astrocytes display important region- and marker-specific differences in the healthy human brain.
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Affiliation(s)
- Liam Anuj O'Leary
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Maria Antonietta Davoli
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, QC, Canada
| | - Claudia Belliveau
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Arnaud Tanti
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, QC, Canada
| | - Jie Christopher Ma
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, QC, Canada
| | - William Todd Farmer
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Center, Montreal General Hospital, Montreal, QC, Canada
| | - Gustavo Turecki
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada.,Department of Psychiatry, McGill University, Montreal, QC, Canada
| | - Keith Kazuo Murai
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Center, Montreal General Hospital, Montreal, QC, Canada
| | - Naguib Mechawar
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada.,Department of Psychiatry, McGill University, Montreal, QC, Canada
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Patodia S, Paradiso B, Ellis M, Somani A, Sisodiya SM, Devinsky O, Thom M. Characterisation of medullary astrocytic populations in respiratory nuclei and alterations in sudden unexpected death in epilepsy. Epilepsy Res 2019; 157:106213. [PMID: 31610338 DOI: 10.1016/j.eplepsyres.2019.106213] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 09/20/2019] [Accepted: 09/30/2019] [Indexed: 12/29/2022]
Abstract
Central failure of respiration during a seizure is one possible mechanism for sudden unexpected death in epilepsy (SUDEP). Neuroimaging studies indicate volume loss in the medulla in SUDEP and a post mortem study has shown reduction in neuromodulatory neuropeptidergic and monoaminergic neurones in medullary respiratory nuclear groups. Specialised glial cells identified in the medulla are considered essential for normal respiratory regulation including astrocytes with pacemaker properties in the pre-Botzinger complex and populations of subpial and perivascular astrocytes, sensitive to increased pCO2, that excite respiratory neurones. Our aim was to explore niches of medullary astrocytes in SUDEP cases compared to controls. In 48 brainstems from three groups, SUDEP (20), epilepsy controls (10) and non-epilepsy controls (18), sections through the medulla were labelled for GFAP, vimentin and functional markers, astrocytic gap junction protein connexin43 (Cx43) and adenosine A1 receptor (A1R). Regions including the ventro-lateral medulla (VLM; for the pre-Bötzinger complex), Median Raphe (MR) and lateral medullary subpial layer (MSPL) were quantified using image analysis for glial cell populations and compared between groups. Findings included morphologically and regionally distinct vimentin/Cx34-positive glial cells in the VLM and MR in close proximity to neurones. We noted a reduction of vimentin-positive glia in the VLM and MSPL and Cx43 glia in the MR in SUDEP cases compared to control groups (p < 0.05-0.005). In addition, we identified vimentin, Cx43 and A1R positive glial cells in the MSPL region which likely correspond to chemosensory glia identified experimentally. In conclusion, altered medullary glial cell populations could contribute to impaired respiratory regulatory capacity and vulnerability to SUDEP and warrant further investigation.
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Affiliation(s)
- Smriti Patodia
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom
| | - Beatrice Paradiso
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom; Cardiovascular Pathology Unit, Department of Cardiac, Thoracic and Vascular Sciences, University of Padua Medical School, Padua, Italy
| | - Matthew Ellis
- Departments of Neuropathology, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom
| | - Alyma Somani
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom
| | - Sanjay M Sisodiya
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom
| | - Orrin Devinsky
- New York University School of Medicine, Comprehensive Epilepsy Center, New York, United States
| | - Maria Thom
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom; Departments of Neuropathology, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom.
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Abstract
AbstractSensory ganglia comprise functional units built up by neurons and satellite glial cells (SGCs). In animal species there was proven the presence of neuronoglial progenitor cells in adult samples. Such neural crest-derived progenitors were found in immunohistochemistry (IHC). These findings were not previously documented in transmission electron microscopy (TEM). It was thus aimed to assess in TEM if cells of the human adult trigeminal ganglion indeed have ultrastructural features to qualify for a progenitor, or quiescent phenotype. Trigeminal ganglia were obtained from fifteen adult donor cadavers. In TEM, cells with heterochromatic nuclei, a pancytoplasmic content of free ribosomes, few perinuclear mitochondria, poor developed endoplasmic reticulum, lack of Golgi complexes and membrane trafficking specializations, were found included in the neuronal envelopes built-up by SGCs. The ultrastructural pattern was strongly suggestive for these cells being quiescent progenitors. However, further experiments should correlate the morphologic and immune phenotypes of such cells.
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