Similar Microglial Cell Densities across Brain Structures and Mammalian Species: Implications for Brain Tissue Function
| Autor: | Lea T. Grinberg, Renata Eloah de Lucena Ferretti-Rebustini, Marcelle Medeiros, Sandra E. Dos Santos, Stephen C. Noctor, Jairo Porfirio, Renata Elaine Paraizo Leite, Jon H. Kaas, William Corrêa Tavares, Chet C. Sherwood, Leila Maria Pessôa, Suzana Herculano-Houzel, Wilson Jacob Filho, Claudia K. Suemoto, Paul R. Manger |
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| Rok vydání: | 2020 |
| Předmět: |
Male
0301 basic medicine 1.1 Normal biological development and functioning Cell Immunocytochemistry microglia Cell Count Biology Medical and Health Sciences 03 medical and health sciences 0302 clinical medicine Species Specificity Underpinning research evolution cell numbers medicine Biological neural network Animals Research Articles Mammals Neurology & Neurosurgery Microglia comparative General Neuroscience Psychology and Cognitive Sciences Neurosciences Brain Evolution of mammals Biological Evolution Brain Disorders Cell biology 030104 developmental biology medicine.anatomical_structure Cerebral cortex Neurological Female Neuron 030217 neurology & neurosurgery Function (biology) cell density |
| Zdroj: | The Journal of neuroscience : the official journal of the Society for Neuroscience, vol 40, iss 24 J Neurosci |
| ISSN: | 1529-2401 0270-6474 |
| DOI: | 10.1523/jneurosci.2339-19.2020 |
| Popis: | Microglial cells play essential volume-related actions in the brain that contribute to the maturation and plasticity of neural circuits that ultimately shape behavior. Microglia can thus be expected to have similar cell sizes and even distribution both across brain structures and across species with different brain sizes. To test this hypothesis, we determined microglial cell densities (the inverse of cell size) using immunocytochemistry to Iba1 in samples of free cell nuclei prepared with the isotropic fractionator from brain structures of 33 mammalian species belonging to males and females of five different clades. We found that microglial cells constitute ∼7% of non-neuronal cells in different brain structures as well as in the whole brain of all mammalian species examined. Further, they vary little in cell density compared with neuronal cell densities within the cerebral cortex, across brain structures, across species within the same clade, and across mammalian clades. As a consequence, we find that one microglial cell services as few as one and as many as 100 neurons in different brain regions and species, depending on the local neuronal density. We thus conclude that the addition of microglial cells to mammalian brains is governed by mechanisms that constrain the size of these cells and have remained conserved over 200 million years of mammalian evolution. We discuss the probable consequences of such constrained size for brain function in health and disease. SIGNIFICANCE STATEMENT Microglial cells are resident macrophages of the CNS, with key functions in recycling synapses and maintaining the local environment in health and disease. We find that microglial cells occur in similar densities in the brains of different species and in the different structures of each individual brain, which indicates that these cells maintain a similar average size in mammalian evolution, suggesting in turn that the volume monitored by each microglial cell remains constant across mammals. Because the density of neurons is highly variable across the same brain structures and species, our finding implies that microglia-dependent functional recovery may be particularly difficult in those brain structures and species with high neuronal densities and therefore fewer microglial cells per neuron. |
| Databáze: | OpenAIRE |
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