Dementia Japan 28:220-230, 2014

Microglia heterogeneity in Alzheimer's disease

Ikuo Tooyama

Molecular Neuroscience Research Center, Shiga University of Medical Science

    Evidence is accumulating that microglia have both protective and degenerative roles in the brain of Alzheimer's disease.  Amyloid-β peptides (Aβ) activate microglia that produce neurotoxic substances such as pro-inflammatory cytokines, complements, reactive oxygen and nitric oxide.  On the other hand, microglia phagocyte Aβ and secrete growth factors and anti-inflammatory cytokines, which are neuroprotective.  In addition, microglia remove damaged cells and ameliorate the normal brain environment.  The diversity of microglial function suggests microglia heterogeneity.  This review focuses on microglia heterogeneity in the brain of Alzheimer's disease.  If neurotoxic functions of microglia (bad microglia) are inhibited and the protective roles (good microglia) are enhanced, microglia could provide a promising future as therapeutic tools for Alzheimer's disease.

Address correspondence to Dr. Ikuo Tooyama, Molecular Neuroscience Research Center, Shiga University of Medical Science (Seta Tsukinowa-cho, Otsu, Shiga 520-2192, Japan)