Interacting Glia in Alzheimer’s Disease

Posted October 25, 2018

Glia cells make up between 33 – 66% of the total brain mass and include microglia, astrocytes, and oligodendrocytes. Microglia perform
immune functions in the cell while astrocytes act as a scaffold for the nervous system.

In a newly published review in Frontiers in Neurology, Dr. Hansang Cho explores the new tools available to study the interactions between astrocytes and microglia during neurodegeneration. Brain inflammation involving glial cell activation is a prominent feature of Alzheimer’s disease. Dr. Cho points to studies suggesting that glial activation is thought to correlate with brain atrophy and cognitive impairments.

Frontiers in Neurology:

The paper is Available Open Access

Alzheimer’s disease (AD) is an irreversible neurodegenerative illness and the exact etiology of the disease remains unknown. It is characterized by long preclinical and prodromal phases with pathological features including an accumulation of amyloid-beta (Aβ) peptides into extracellular Aβ plaques in the brain parenchyma and the formation of intracellular neurofibrillary tangles (NFTs) within neurons as a result of abnormal phosphorylation of microtubule-associated tau proteins. In addition, prominent activation of innate immune cells is also observed and/or followed by marked neuroinflammation. While such neuroinflammatory responses may function in a neuroprotective manner by clearing neurotoxic factors, they can also be neurotoxic by contributing to neurodegeneration via elevated levels of proinflammatory mediators and oxidative stress, and altered levels of neurotransmitters, that underlie pathological symptoms including synaptic and cognitive impairment, neuronal death, reduced memory, and neocortex and hippocampus malfunctions. Glial cells, particularly activated microglia and reactive astrocytes, appear to play critical and interactive roles in such dichotomous responses. Accumulating evidence clearly point to their critical involvement in the prevention, initiation, and progression, of neurodegenerative diseases, including AD. Here, we review recent findings on the roles of astrocyte-microglial interactions in neurodegeneration in the context of an AD and discuss newly developed in vitro and in vivo experimental models that will enable more detailed analysis of glial interplay. An increased understanding of the roles of glia and the development of new exploratory tools are likely to be crucial for the development of new interventions for early stage AD prevention and cures.

Image courtesy of the National Institute on Aging/National Institutes of Health