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Review
. 2021 Apr 22;22(9):4402.
doi: 10.3390/ijms22094402.

Senescent Microglia: The Key to the Ageing Brain?

Eleanor K Greenwood  1 , David R Brown  1
Affiliations
Review

Senescent Microglia: The Key to the Ageing Brain?

Eleanor K Greenwood et al. Int J Mol Sci. .

Abstract

Ageing represents the single biggest risk factor for development of neurodegenerative disease. Despite being such long-lived cells, microglia have been relatively understudied for their role in the ageing process. Reliably identifying aged microglia has proven challenging, not least due to the diversity of cell populations, and the limitations of available models, further complicated by differences between human and rodent cells. Consequently, the literature contains multiple descriptions and categorisations of microglia with neurotoxic phenotypes, including senescence, without any unifying markers. The role of microglia in brain homeostasis, particularly iron storage and metabolism, may provide a key to reliable identification.

Keywords: Senescence Associated Secretory Phenotype; ageing; iron; microglia; neurodegeneration; senescence.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Microglia can extend and retract their processes, making brief contacts with synaptic structures whilst in the surveillance state.
Figure 2
Figure 2
Changes in microglial state are associated with changes in morphology, gene expression, and behaviour. Disease-associated or -activated microglia tend to be more amoeboid in shape, with retracted processes, and demonstrate increased phagocytosis. Dystrophic or senescent microglia exhibit cytorrhexis, and a decrease in phagocytosis and motility.
See this image and copyright information in PMC

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