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Updated: May 29, 2026
An In Vitro Model for the Study of Cellular Pathophysiology in Globoid Cell Leukodystrophy
Published on: October 21, 2014
A comparison of in vitro properties of resting SOD1 transgenic microglia reveals evidence of reduced neuroprotective
Siranush A Sargsyan1, Daniel J Blackburn, Siân C Barber
1Department of Medicine, University of Colorado Denver School of Medicine, CO, USA. anna_sargsyan@hotmail.com
Background:
Overexpression of mutant copper/zinc superoxide dismutase (SOD1) in rodents has provided useful models for studying the pathogenesis of amyotrophic lateral sclerosis (ALS). Microglia have been shown to contribute to ALS disease progression in these models, although the mechanism of this contribution remains to be elucidated. Here, we present the first evidence of the effects of overexpression of mutant (TG G93A) and wild type (TG WT) human SOD1 transgenes on a set of functional properties of microglia relevant to ALS progression, including expression of integrin β-1, spreading and migration, phagocytosis of apoptotic neuronal cell debris, and intracellular calcium changes in response to an inflammatory stimulus.
Results:
TG SOD1 G93A but not TG SOD1 WT microglia had lower expression levels of the cell adhesion molecule subunit integrin β-1 than their NTG control cells [NTG (G93A) and NTG (WT), respectively, 92.8 ± 2.8% on TG G93A, 92.0 ± 6.6% on TG WT, 100.0 ± 1.6% on NTG (G93A), and 100.0 ± 2.7% on NTG (WT) cells], resulting in decreased spreading ability, with no effect on ability to migrate. Both TG G93A and TG WT microglia had reduced capacity to phagocytose apoptotic neuronal cell debris (13.0 ± 1.3% for TG G93A, 16.5 ± 1.9% for TG WT, 28.6 ± 1.8% for NTG (G93A), and 26.9 ± 2.8% for NTG (WT) cells). Extracellular stimulation of microglia with ATP resulted in smaller increase in intracellular free calcium in TG G93A and TG WT microglia relative to NTG controls (0.28 ± 0.02 μM for TG G93A, 0.24 ± 0.03 μM for TG WT, 0.39 ± 0.03 μM for NTG (G93A), and 0.37 ± 0.05 μM for NTG (WT) microglia).
Conclusions:
These findings indicate that, under resting conditions, microglia from mutant SOD1 transgenic mice have a reduced capacity to elicit physiological responses following tissue disturbances and that higher levels of stimulatory signals, and/or prolonged stimulation may be necessary to initiate these responses. Overall, resting mutant SOD1-overexpressing microglia may have reduced capacity to function as sensors of disturbed tissue/cellular homeostasis in the CNS and thus have reduced neuroprotective function.
Insights
Microglia in mutant SOD1 models of ALS show reduced function, including lower integrin β-1 expression and impaired phagocytosis. These cells may have a diminished capacity to sense cellular disturbances, potentially reducing neuroprotection in ALS.
Area of Science:
- Neuroscience
- Immunology
- Genetics
Background:
- Amyotrophic lateral sclerosis (ALS) pathogenesis is studied in rodent models overexpressing mutant copper/zinc superoxide dismutase (SOD1).
- Microglia are implicated in ALS progression, but their precise contribution mechanism requires elucidation.
Purpose of the Study:
- To investigate the impact of mutant (TG G93A) and wild-type (TG WT) human SOD1 transgene overexpression on key microglial functions relevant to ALS.
- To assess effects on integrin β-1 expression, cell spreading and migration, phagocytosis of neuronal debris, and intracellular calcium responses.
Main Methods:
- Comparison of microglial functional properties between SOD1 transgenic mice (TG G93A, TG WT) and non-transgenic (NTG) controls.
- Assessment of integrin β-1 expression, cell spreading and migration assays, phagocytosis assays, and intracellular calcium measurements following ATP stimulation.
Main Results:
- Mutant SOD1 (TG G93A) microglia exhibited lower integrin β-1 expression and reduced spreading ability compared to controls.
- Both mutant (TG G93A) and wild-type (TG WT) SOD1 microglia showed decreased phagocytosis of apoptotic neuronal debris.
- Microglia from SOD1 transgenic mice displayed attenuated intracellular calcium increases upon inflammatory stimulation.
Conclusions:
- Resting microglia from mutant SOD1 transgenic mice demonstrate a reduced capacity to respond to tissue disturbances.
- Enhanced or prolonged stimulation may be required to activate these microglia.
- Mutant SOD1-overexpressing microglia may have impaired neuroprotective functions due to reduced sensing of CNS homeostasis disruptions.
