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Updated: Apr 17, 2026
Three-dimensional Confocal Analysis of Microglia/macrophage Markers of Polarization in Experimental Brain Injury
Published on: September 4, 2013
Selective modulation of microglia polarization to M2 phenotype for stroke treatment
Cong-Yuan Xia1, Shuai Zhang1, Yan Gao1
1State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
Abstract:
Resident microglia are the major immune cells in the brain, acting as the first defense of the central nervous system. Following cerebral ischemia, microglia respond to this injury at first and transform from surveying microglia to active state. The activated microglia play a dual role in the ischemic injury, due to distinct microglia phenotypes, including deleterious M1 and neuroprotective M2. However, microglia show transient M2 phenotype followed by a shift to M1. The high ratio of M1 to M2 is significantly related to ischemic injury. Many signal pathways participate in the alternation of microglial phenotype, presenting potential therapeutic targets for selectively modulating M2 polarization of microglia. In this review, we discuss how the M2 phenotype mediates neuroprotective effects and summarize the alternation of signaling cascades that control microglial phenotype after ischemic stroke.
Insights
Resident microglia, the brain's immune cells, shift phenotypes after ischemic stroke. Targeting signaling pathways to promote neuroprotective M2 microglia may reduce brain injury.
Area of Science:
- Neuroscience
- Immunology
- Cerebrovascular disease
Background:
- Microglia are the primary immune cells in the central nervous system.
- Following cerebral ischemia, microglia transition from a resting to an activated state.
- Activated microglia exhibit distinct M1 (deleterious) and M2 (neuroprotective) phenotypes.
Purpose of the Study:
- To review the neuroprotective mechanisms of the M2 microglia phenotype.
- To summarize the signaling pathways that regulate microglial phenotype switching after ischemic stroke.
- To identify potential therapeutic targets for modulating microglial responses in stroke.
Main Methods:
- Literature review of studies on microglia in cerebral ischemia.
- Analysis of signaling cascades involved in microglial polarization.
- Discussion of the dual role of microglia phenotypes in ischemic injury.
Main Results:
- Microglia play a critical role in the initial response to cerebral ischemia.
- The M2 phenotype confers neuroprotection, but it is transient and often shifts to the M1 phenotype.
- A high M1 to M2 ratio is associated with increased ischemic injury.
Conclusions:
- Microglial phenotype modulation is a promising therapeutic strategy for ischemic stroke.
- Understanding the signaling pathways controlling microglial polarization is key to developing targeted treatments.
- Promoting M2 polarization could mitigate brain damage following stroke.
