NG2 proteoglycan-expressing microglia as multipotent neural progenitors in normal and pathologic brains

Area of Science:

• Neuroscience
• Stem Cell Biology
• Developmental Biology

Background:

• Microglia (MG), the resident immune cells of the brain, are increasingly recognized for roles beyond immunity.
• The potential of microglia to differentiate into other neural cell types remains an area of active investigation.

Purpose of the Study:

• To investigate the multipotent differentiation potential of rat primary microglia.
• To identify specific microglial markers and their role in neurogenesis and brain repair.

Main Methods:

• Primary microglia culture from neonatal rat brains.
• Two-step culture in varying serum concentrations to induce differentiation.
• Immunohistochemistry to identify cell markers (NG2, GFAP, NCAM, S-100beta, beta-tubulin III).
• Analysis of microglia in experimentally induced brain wounds.

Main Results:

• Primary microglia cultured in serum-supplemented media acquired multipotency, forming promicroglioblasts (ProMGBs).
• NG2+ microglia were identified in neonatal brains and accumulated at sites of injury in mature brains.
• ProMGB aggregates generated neuroectodermal cells in vitro, including beta-tubulin III+ cells.
• NG2+ microglia persisted in brain wounds for up to 150 days post-lesioning.

Conclusions:

• Rat primary microglia possess multipotent properties, differentiating into neuroectodermal cells.
• NG2+ microglia are present in normal developing and injured brains.
• These findings suggest a role for NG2+ microglia in brain development and repair processes.