Central Nervous System Macrophages in Health and Disease

Area of Science:

• Neuroimmunology
• Cellular and Molecular Neuroscience

Background:

• The central nervous system (CNS) harbors distinct resident macrophage populations, microglia and border-associated macrophages, crucial for maintaining brain homeostasis during development and steady states.
• In pathological conditions, the CNS immune environment changes, characterized by alterations in resident macrophages and the infiltration of blood-borne monocytes.

Purpose of the Study:

• To review the roles and functions of CNS macrophages in both healthy and diseased states, specifically focusing on neurodegenerative diseases and neuroinflammation.
• To elucidate the distinct contributions of monocyte-derived macrophages versus resident macrophages in neuropathology.

Main Methods:

• This review synthesizes current literature on CNS macrophage populations.
• It examines their phenotypes, functions, and origins in various neurological conditions.

Main Results:

• Resident CNS macrophages (microglia, border-associated macrophages) are vital for brain homeostasis and exhibit neuroprotective functions during disease.
• Infiltrating monocyte-derived macrophages are implicated in exacerbating neuropathology in conditions like amyloidosis, multiple sclerosis, and CNS infections.

Conclusions:

• Understanding the differential roles of CNS macrophage subsets is critical for developing targeted therapies for neurological disorders.
• Distinguishing between neuroprotective resident macrophages and potentially detrimental monocyte-derived macrophages offers therapeutic avenues for CNS diseases.