Microglia are activated in neurodegenerative
& neuroinflammatory diseases
Characteristics of microglia activation
- Increased proliferation & density
- Morphological changes
- Increase in soma size
- Alterations of processes
- Fine & extended to short & dense
- Spiky/hairy with thick processes
Multiple morphological features have been correlated with the degree of activation (Fernández-Arjona, 2019).
Resting microglia: extended with fine processes
Activated microglia: spiky/hairy with thick processes
Proliferation
(images reproduced from Schwabenland et al., 2021; http://creativecommons.org/licenses/by/4.0)
References
Fernández-Arjona et al., Front. Cell. Neurosci., 13: 472, 2019; doi: 10.3389/fncel.2019.00472
Schwabenland et al., Acta. Neuropathol., 142: 923-936, 2021; doi: 10.1007/s00401-021-02370-8
Microgliosis is implicated in most neurodegenerative and neuroinflammatory diseases. As part of the pathologic changes, microglia proliferate, migrate, and become activated. This process results in an overall increase in the Iba-1 protein density, which can be quantified using immunohistochemical (IHC) methods.
Microglial activation also results in characteristic morphological changes. The soma increases in size and the processes change from fine and extended, to short and dense, with an appearance that can sometimes be hairy or spiky. In addition, recent reports have correlated several morphological features with the degree of activation.
As such, in order to obtain the most sensitive measurement of microgliosis, we have developed a fully-automated microglial identification and characterization pipeline. In this presentation, we will show how this approach can provide sensitive metrics that are complementary to the Iba-1 staining density.