Characterizing microglial gene expression in a model of secondary progressive multiple sclerosis

Area of Science:

• Neuroimmunology
• Cellular and Molecular Neuroscience

Background:

• Multiple sclerosis (MS) is a leading cause of neurological disability in young adults.
• The role of microglia, the central nervous system's immune cells, is unclear in MS, particularly in its progressive phases.
• Chronic-relapsing experimental autoimmune encephalomyelitis (crEAE) in mice serves as a model for MS.

Purpose of the Study:

• To investigate the dynamic changes in microglia phenotypes during different phases of crEAE.
• To characterize microglia's role in acute, remission, and chronic stages of this MS model.

Main Methods:

• Morphometric analysis of microglia.
• RNA sequencing to analyze gene expression profiles of microglia.
• Utilizing the crEAE mouse model.

Main Results:

• During the acute phase, microglia exhibited a pro-inflammatory phenotype.
• In the remission phase, microglia showed decreased immune gene expression and increased genes for lipid metabolism and tissue repair.
• Chronic phase microglia displayed a mixed phenotype, with partial restoration of inflammatory genes and increased proliferation markers.

Conclusions:

• Microglia adopt distinct phenotypes across different stages of crEAE.
• The chronic stage is characterized by a complex, mixed microglia phenotype.
• Insights into chronic-stage microglia are crucial for understanding secondary progressive MS and developing targeted therapies.