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Updated: Aug 23, 2026
A Multi-Cue Bioreactor to Evaluate the Inflammatory and Regenerative Capacity of Biomaterials under Flow and Stretch
Published on: December 10, 2020
Biolistic expression of the macrophage colony stimulating factor receptor in organotypic cultures induces an
Olivera M Mitrasinovic1, Christopher C Robinson, Daniel G Tenen
1Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, California 94305-5485, USA.
Abstract:
The receptor for macrophage colony-stimulating factor (M-CSFR; c-fms) is expressed at increased levels by microglia in Alzheimer's disease (AD) and in mouse models for AD. Increased expression of M-CSFR on cultured microglia results in a strong proinflammatory response, but the relevance of this cell culture finding to intact brain is unknown. To determine the effects of increased microglial expression of M-CSFR in a complex organotypic environment, we developed a system for biolistic transfection of microglia in hippocampal slice cultures. The promoter for the Mac-1 integrin alpha subunit CD11b is active in cells of myeloid origin. In the brain, CD11b expression is restricted to microglia. Constructs consisting of the promoter for CD11b and a c-fms cDNA or an enhanced green fluorescent protein (EGFP) cDNA were introduced into monotypic cultures of microglia, neurons, and astrocytes. Strong CD11b promoter activity was observed in microglia, whereas little activity was observed in other cell types. Biolistic transfection of organotypic hippocampal cultures with the CD11b/c-fms construct resulted in expression of the c-fms mRNA and protein that was localized to microglia. Furthermore, biolistic overexpression of M-CSFR on microglia resulted in significantly increased production by the hippocampal cultures of the proinflammatory cytokines interleukin (IL)-1alpha macrophage inflammatory protein (MIP-1alpha), and trends toward increased production of IL-6 and M-CSF. These findings demonstrate that microglial overexpression of M-CSFR in an organotypic environment induces an inflammatory response, and suggest that increased microglial expression of M-CSFR could contribute to the inflammatory response observed in AD brain.
Insights
Increased macrophage colony-stimulating factor receptor (M-CSFR) expression in microglia drives inflammation in Alzheimer's disease (AD) models. This study confirms M-CSFR's role in promoting proinflammatory cytokine production within the brain environment.
Area of Science:
- Neuroscience
- Immunology
- Cell Biology
Background:
- Microglia, the brain's immune cells, overexpress the macrophage colony-stimulating factor receptor (M-CSFR) in Alzheimer's disease (AD).
- Elevated M-CSFR on cultured microglia induces a proinflammatory response, but its relevance in the intact brain remains unclear.
Purpose of the Study:
- To investigate the effects of increased M-CSFR expression on microglia within a complex organotypic brain environment.
- To determine if M-CSFR overexpression in microglia contributes to neuroinflammation relevant to AD.
Main Methods:
- Developed a biolistic transfection system to introduce genetic constructs into microglia within organotypic hippocampal slice cultures.
- Utilized the CD11b promoter, specific to myeloid cells like microglia, to drive M-CSFR expression.
- Quantified mRNA and protein levels of M-CSFR and measured the production of proinflammatory cytokines.
Main Results:
- Successfully achieved microglia-specific M-CSFR overexpression in organotypic hippocampal cultures.
- Demonstrated significantly increased production of interleukin-1alpha and macrophage inflammatory protein-1alpha.
- Observed trends toward increased interleukin-6 and M-CSF production, indicating a proinflammatory shift.
Conclusions:
- Microglial M-CSFR overexpression in an organotypic brain environment induces a significant inflammatory response.
- These findings suggest that elevated M-CSFR on microglia may contribute to the neuroinflammation observed in Alzheimer's disease.
