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Updated: Jun 5, 2026
Assessing Retinal Microglial Phagocytic Function In Vivo Using a Flow Cytometry-based Assay
Published on: October 18, 2016
Macrophage colony-stimulating factor and its receptor signaling augment glycated albumin-induced retinal microglial
Wei Liu1, Ge Z Xu, Chun H Jiang
1Department of Opthalmology, EENT Hospital, Eye Institute, Fudan University, Shanghai, 200031, China.
Background:
Microglial activation and the proinflammatory response are controlled by a complex regulatory network. Among the various candidates, macrophage colony-stimulating factor (M-CSF) is considered an important cytokine. The up-regulation of M-CSF and its receptor CSF-1R has been reported in brain disease, as well as in diabetic complications; however, the mechanism is unclear. An elevated level of glycated albumin (GA) is a characteristic of diabetes; thus, it may be involved in monocyte/macrophage-associated diabetic complications.
Results:
The basal level of expression of M-CSF/CSF-1R was examined in retinal microglial cells in vitro. Immunofluorescence, real-time PCR, immunoprecipitation, and Western blot analyses revealed the up-regulation of CSF-1R in GA-treated microglial cells. We also detected increased expression and release of M-CSF, suggesting that the cytokine is produced by activated microglia via autocrine signaling. Using an enzyme-linked immunosorbent assay, we found that GA affects microglial activation by stimulating the release of tumor necrosis factor-α and interleukin-1β. Furthermore, the neutralization of M-CSF or CSF-1R with antibodies suppressed the proinflammatory response. Conversely, this proinflammatory response was augmented by the administration of M-CSF.
Conclusions:
We conclude that GA induces microglial activation via the release of proinflammatory cytokines, which may contribute to the inflammatory pathogenesis of diabetic retinopathy. The increased microglial expression of M-CSF/CSF-1R not only is a response to microglial activation in diabetic retinopathy but also augments the microglial inflammation responsible for the diabetic microenvironment.
Insights
Glycated albumin (GA) activates microglia, releasing inflammatory cytokines like M-CSF and TNF-α, contributing to diabetic retinopathy. Targeting M-CSF/CSF-1R may reduce this microglial inflammation.
Area of Science:
- Neuroimmunology
- Ophthalmology
- Endocrinology
Background:
- Microglial activation is key in neuroinflammation.
- Macrophage colony-stimulating factor (M-CSF) and its receptor (CSF-1R) are implicated in diabetic complications.
- The role of M-CSF/CSF-1R in diabetes-related microglial activation is unclear.
Purpose of the Study:
- To investigate the role of glycated albumin (GA) in microglial activation.
- To elucidate the involvement of M-CSF/CSF-1R signaling in GA-induced microglial responses.
- To assess the contribution of these pathways to diabetic retinopathy pathogenesis.
Main Methods:
- In vitro studies using retinal microglial cells.
- Analysis of M-CSF/CSF-1R expression via immunofluorescence, real-time PCR, immunoprecipitation, and Western blot.
- Measurement of cytokine release (TNF-α, IL-1β) using ELISA.
- Inhibition and augmentation studies using antibodies and M-CSF administration.
Main Results:
- GA up-regulated CSF-1R expression and M-CSF release in microglial cells.
- GA stimulated the release of proinflammatory cytokines (TNF-α, IL-1β).
- Neutralizing M-CSF or CSF-1R suppressed inflammation; M-CSF administration augmented it.
Conclusions:
- GA induces microglial activation and inflammation via M-CSF/CSF-1R signaling.
- This pathway contributes to the inflammatory pathogenesis of diabetic retinopathy.
- M-CSF/CSF-1R signaling exacerbates microglial inflammation in the diabetic microenvironment.
