Related Experiment Video
Updated: Jun 14, 2026
In Vivo Dynamics of Retinal Microglial Activation During Neurodegeneration: Confocal Ophthalmoscopic Imaging and Cell Morphometry in Mouse Glaucoma
Published on: May 11, 2015
Microglia in the aging brain: relevance to neurodegeneration
Xiao-Guang Luo1, Jian-Qing Ding, Sheng-Di Chen
1Department of Neurology and Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, PR China. chen_sd@medmail.com.cn.
Abstract:
Microglia cells are the brain counterpart of macrophages and function as the first defense in the brain. Although they are neuroprotective in the young brain, microglia cells may be primed to react abnormally to stimuli in the aged brain and to become neurotoxic and destructive during neurodegeneration. Aging-induced immune senescence occurs in the brain as age-associated microglia senescence, which renders microglia to function abnormally and may eventually promote neurodegeneration. Microglia senescence is manifested by both morphological changes and alterations in immunophenotypic expression and inflammatory profile. These changes are likely caused by microinvironmental factors, but intrinsic factors cannot yet be completely excluded. Microglia senescence appears to underlie the switching of microglia from neuroprotective in the young brain to neurotoxic in the aged brain. The hypothesis of microglia senescence during aging offers a novel perspective on their roles in aging-related neurodegeneration. In Parkinson's disease and Alzheimer's disease, over-activation of microglia may play an active role in the pathogenesis because microglia senescence primes them to be neurotoxic during the development of the diseases.
Insights
In aging brains, microglia (brain immune cells) shift from protective to harmful roles, contributing to neurodegeneration. This age-associated microglia senescence drives neurotoxic changes seen in diseases like Alzheimer's.
Area of Science:
- Neuroscience
- Immunology
- Aging Research
Background:
- Microglia are the brain's primary immune cells, crucial for defense.
- In young brains, microglia are neuroprotective, but in aged brains, they can become neurotoxic.
- Age-associated microglia senescence leads to abnormal function and promotes neurodegeneration.
Purpose of the Study:
- To investigate the role of microglia senescence in brain aging and neurodegeneration.
- To understand how microglia change from neuroprotective to neurotoxic with age.
- To explore the implications of microglia senescence in neurodegenerative diseases.
Main Methods:
- The study focuses on the concept of age-associated microglia senescence.
- Analysis of morphological, immunophenotypic, and inflammatory changes in microglia.
- Review of existing hypotheses and evidence regarding microglia function in aging and disease.
Main Results:
- Microglia senescence involves morphological and immunophenotypic alterations.
- Senescent microglia exhibit an altered inflammatory profile.
- This senescence is linked to the shift from neuroprotective to neurotoxic functions in the aged brain.
Conclusions:
- Microglia senescence is a key factor in the transition of microglia from beneficial to detrimental roles in the aging brain.
- This phenomenon offers a new perspective on the pathogenesis of age-related neurodegenerative diseases.
- Primed, senescent microglia may actively contribute to the progression of Parkinson's and Alzheimer's diseases.
