[Age-related brain functional changes and microglia]
Yoki Nakamura1, Kazue Hisaoka-Nakashima1, Norimitsu Morioka1
1Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University.
Abstract:
Age-related alterations in brain function are considered a physiological phenomenon that everyone may experience as a decline in memory and cognitive abilities. However, the rate of progression varies among individuals, and the underlying mechanisms remain largely unclear. Microglia, the resident immune cells of the brain, play a crucial role in maintaining central nervous system homeostasis through diverse functions such as phagocytosis of cellular debris, synaptic pruning, and regulation of neuroinflammatory responses. Previous studies have demonstrated that the cellular morphology of microglia undergoes significant changes with age. Furthermore, recent advances in RNA sequencing analysis techniques have revealed that microglia are not a homogeneous cell population but rather consist of diverse subpopulations. Notably, white matter-associated microglia (WAM) and interferon-response microglia (IRM) are reported to increase in proportion with aging. Thus, aging induces complex changes in the morphology, function, and subpopulation composition of microglia, which may impair the homeostatic maintenance of brain and contribute to age-related alterations in brain function, such as cognitive decline. This review focuses on the impact of aging on microglia and their association with changes in brain function, presenting the latest findings in this field.
Insights
Aging alters brain microglia, the immune cells of the brain. These changes in microglia subpopulations and function may contribute to age-related cognitive decline and memory loss.
Area of Science:
- Neuroscience
- Immunology
- Aging Research
Background:
- Age-related cognitive decline is common but varies individually.
- Microglia, brain's immune cells, are vital for central nervous system homeostasis.
- Microglial morphology and function change significantly with age.
Purpose of the Study:
- To review the impact of aging on microglia.
- To explore the association between microglial changes and brain function alterations.
- To present current findings on aging microglia and cognitive function.
Main Methods:
- Review of existing literature on microglia and aging.
- Analysis of RNA sequencing data on microglial subpopulations.
- Examination of studies on microglial morphology and function changes over time.
Main Results:
- Microglia exhibit significant morphological changes with age.
- Aging leads to diverse microglial subpopulations, including increased white matter-associated microglia (WAM) and interferon-response microglia (IRM).
- These aging-induced microglial alterations may impair brain homeostasis.
Conclusions:
- Aging profoundly affects microglia's composition, morphology, and function.
- Changes in microglia are linked to age-related cognitive decline.
- Further research into aging microglia is crucial for understanding and mitigating cognitive impairment.
