Activation of microglia acidifies lysosomes and leads to degradation of Alzheimer amyloid fibrils Academic Article uri icon


MeSH Major

  • Amyloid beta-Peptides
  • Lysosomes
  • Microglia


  • Microglia are the main immune cells of the brain, and under some circumstances they can play an important role in removal of fibrillar Alzheimer amyloid beta peptide (fAbeta). Primary mouse microglia can internalize fAbeta, but they do not degrade it efficiently. We compared the level of lysosomal proteases in microglia and J774 macrophages, which can degrade fAbeta efficiently, and we found that microglia actually contain higher levels of many lysosomal proteases than macrophages. However, the microglial lysosomes are less acidic (average pH of approximately 6), reducing the activity of lysosomal enzymes in the cells. Proinflammatory treatments with macrophage colony-stimulating factor (MCSF) or interleukin-6 acidify the lysosomes of microglia and enable them to degrade fAbeta. After treatment with MCSF, the pH of microglial lysosomes is similar to J774 macrophages (pH of approximately 5), and the MCSF-induced acidification can be partially reversed upon treatment with an inhibitor of protein kinase A or with an anion transport inhibitor. Microglia also degrade fAbeta if lysosomes are acidified by an ammonia pulse-wash or by treatment with forskolin, which activates protein kinase A. Our results indicate that regulated lysosomal acidification can potentiate fAbeta degradation by microglia.

publication date

  • April 2007



  • Academic Article



  • eng

PubMed Central ID

  • PMC1838985

Digital Object Identifier (DOI)

  • 10.1091/mbc.E06-10-0975

PubMed ID

  • 17314396

Additional Document Info

start page

  • 1490

end page

  • 6


  • 18


  • 4