Related Experiment Video
Updated: May 2, 2026
Experimental Demyelination and Remyelination of Murine Spinal Cord by Focal Injection of Lysolecithin
Published on: March 26, 2015
Macrophages and CNS remyelination
Veronique E Miron1, Robin J M Franklin
1MRC Centre for Reproductive Health, The Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, UK.
Abstract:
Microglia are the resident macrophages of the central nervous system that survey the microenvironment for signals of injury or infection. The response to such signals induces an inflammatory response involving macrophages derived from both resident microglia and recruited circulating monocytes. Although implicated as contributors to autoimmune-mediated injury, microglia/ macrophages have recently been shown to be critical for the important central nervous system regenerative process of remyelination. This functional dichotomy may reflect their ability to be polarized along a continuum of activation states including the well-characterized cytotoxic M1 and regenerative M2 phenotypes. Here, we review the roles of microglia, monocytes and the macrophages which they give rise to in creating lesion environments favourable to remyelination, highlighting the specific roles of M1 and M2 phenotypes and how the pro-regenerative role of the innate immune system is altered by ageing. Here, we review the roles of microglia, monocytes and the macrophages, which they give rise to in creating lesion environments favourable to remyelination, highlighting the specific roles of activation phenotypes and how the pro-regenerative role of the innate immune system is altered by ageing.
Insights
Microglia and macrophages play dual roles in the central nervous system, contributing to injury and repair. Their activation states, M1 and M2, are crucial for remyelination, but this process is impacted by aging.
Area of Science:
- Neuroimmunology
- Cellular Biology
- Regenerative Medicine
Background:
- Microglia are the primary immune cells in the central nervous system (CNS).
- Both resident microglia and circulating monocytes contribute to CNS inflammation and repair.
- Microglia/macrophages have demonstrated critical roles in the CNS regenerative process of remyelination.
Purpose of the Study:
- To review the roles of microglia, monocytes, and their derived macrophages in creating lesion environments conducive to remyelination.
- To highlight the specific functions of M1 (cytotoxic) and M2 (regenerative) activation phenotypes.
- To examine how aging affects the pro-regenerative capacity of the innate immune system in the CNS.
Main Methods:
- Literature review of studies on microglia, monocytes, and macrophages in CNS injury and repair.
- Analysis of the functional dichotomy of microglia/macrophage activation states (M1 vs. M2).
- Examination of the impact of aging on immune cell-mediated remyelination.
Main Results:
- Microglia and macrophages exhibit distinct activation phenotypes (M1/M2) influencing CNS lesion environments.
- M2 macrophages are associated with pro-regenerative processes, including remyelination.
- Aging can alter the balance of these phenotypes, potentially impairing the regenerative capacity of the innate immune system.
Conclusions:
- Microglia and macrophages are key players in CNS repair, with their activation states dictating outcomes.
- Understanding M1/M2 phenotypes is crucial for developing strategies to promote remyelination.
- Age-related changes in the innate immune system present a significant challenge for CNS regeneration.
Related Concept Videos
01:15Neurogenesis and Regeneration of Nervous Tissue
01:25Nervous Tissue: Myelin
Schwann cells begin to form myelin sheaths around axons during fetal development. They wrap around a small...