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Activated microglia (BV-2) facilitation of TNF-alpha-mediated motor neuron death in vitro
Bei Ping He1, Weiyan Wen, Michael J Strong
1Neurodegeneration Research Group, The John P. Robarts Research Institute, University of Western Ontario, London, Ontario, Canada N6A 5A5. mstrong@uwo.co
Abstract:
We have studied the interactions between activated microglia and injured motor neurons using an immortalized murine microglial cell line (BV-2) stimulated with either lipopolysaccharide (LPS) (Escherichia coli) or supernatant from serum-deprived motor neurons (NSC-34 cell line). Both stimuli induced BV-2 activation. Although both BV-2 supernatants induced a subsequent increase in NO generation in otherwise healthy NSC-34 cells, only LPS-activated microglial supernatant induced NSC-34 cell death through a TNF-alpha-dependent pathway. However, we observed a 20-fold increase in the amount of TNF-alpha required to kill NSC-34 cells in the absence of LPS-activated BV-2 cell supernatant, indicating that microglia secrete factor(s) that facilitate TNF-alpha-mediated motor neuron death in vitro.
Insights
Activated microglia contribute to motor neuron death. Lipopolysaccharide (LPS)-activated microglia release factors that enhance tumor necrosis factor-alpha (TNF-α)-mediated motor neuron (NSC-34) cell death in vitro.
Area of Science:
- Neuroscience
- Immunology
- Cell Biology
Background:
- Microglia are the primary immune cells of the central nervous system.
- Activated microglia play a role in neuroinflammation and neuronal injury.
- Motor neuron degeneration is a hallmark of various neurological disorders.
Purpose of the Study:
- To investigate the interaction between activated microglia and motor neurons.
- To determine the role of microglia-derived factors in motor neuron death.
- To elucidate the mechanisms underlying microglial-mediated neurotoxicity.
Main Methods:
- Utilized an immortalized murine microglial cell line (BV-2) stimulated with lipopolysaccharide (LPS) or motor neuron supernatant.
- Assessed nitric oxide (NO) generation in BV-2 and motor neuron (NSC-34) cells.
- Investigated cell death pathways, including tumor necrosis factor-alpha (TNF-α)-dependent mechanisms.
Main Results:
- Both LPS and motor neuron supernatant activated BV-2 microglia.
- Activated BV-2 supernatants increased NO generation in NSC-34 cells.
- LPS-activated BV-2 supernatant induced NSC-34 cell death via a TNF-α-dependent pathway.
- Microglia-derived factors were found to facilitate TNF-α-mediated motor neuron death.
Conclusions:
- Activated microglia can contribute to motor neuron injury.
- Microglia secrete factors that potentiate TNF-α toxicity to motor neurons.
- These findings highlight a potential mechanism in neurodegenerative diseases involving microglial activation.