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Microglia as a Surrogate Biosensor to Determine Nanoparticle Neurotoxicity
Published on: October 25, 2016
The brain's best friend: microglial neurotoxicity revisited
Sabine Hellwig1, Annette Heinrich, Knut Biber
1Department of Psychiatry and Psychotherapy, University Hospital Freiburg Freiburg, Germany.
Abstract:
One long standing aspect of microglia biology was never questioned; their involvement in brain disease. Based on morphological changes (retracted processes and amoeboid shape) that inevitably occur in these cells in case of damage in the central nervous system, microglia in the diseased brain were called "activated." Because "activated" microglia were always found in direct neighborhood to dead or dying neuron, and since it is known now for more than 20 years that cultured microglia release numerous factors that are able to kill neurons, microglia "activation" was often seen as a neurotoxic process. From an evolutionary point of view, however, it is difficult to understand why an important, mostly post-mitotic and highly vulnerable organ like the brain would host numerous potential killers. This review is aimed to critically reconsider the term microglia neurotoxicity and to discuss experimental problems around microglia biology, that often have led to the conclusion that microglia are neurotoxic cells.
Insights
Microglia, immune cells in the brain, are often considered neurotoxic due to their role in brain disease. This review questions this long-held assumption, exploring experimental issues that may have led to this conclusion.
Area of Science:
- Neuroscience
- Immunology
- Cell Biology
Background:
- Microglia are brain immune cells traditionally linked to disease.
- Morphological changes in microglia during central nervous system damage led to their classification as "activated."
- Activated microglia are often observed near damaged neurons, and in vitro studies show they can release neurotoxic factors.
Purpose of the Study:
- To critically re-evaluate the concept of microglia neurotoxicity.
- To discuss experimental challenges in microglia biology research.
- To challenge the prevailing view of microglia as inherently neurotoxic.
Main Methods:
- Literature review and critical analysis of existing studies on microglia.
- Examination of the evolutionary perspective on microglia function.
- Discussion of experimental artifacts and limitations in microglia research.
Main Results:
- The traditional view of microglia as "activated" and neurotoxic is questioned.
- Evolutionary considerations suggest a protective role for microglia might be more plausible.
- Experimental methodologies may have contributed to misinterpretations of microglia function.
Conclusions:
- The term "microglia neurotoxicity" requires critical reconsideration.
- Further research is needed to understand the complex role of microglia in brain health and disease.
- A nuanced understanding of microglia biology, beyond simple activation and neurotoxicity, is essential.
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