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TGF-β Promotes the Proliferation of Microglia In Vitro
Costansia Bureta1, Takao Setoguchi2, Yoshinobu Saitoh1
1Department of Orthopaedic Surgery, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8520, Japan.
Abstract:
The activation and proliferation of microglia is characteristic of the early stages of brain pathologies. In this study, we aimed to identify a factor that promotes microglial activation and proliferation and examined the in vitro effects on these processes. We cultured microglial cell lines, EOC 2 and SIM-A9, with various growth factors and evaluated cell proliferation, death, and viability. The results showed that only transforming growth factor beta (TGF-β) caused an increase in the in vitro proliferation of both microglial cell lines. It has been reported that colony-stimulating factor 1 promotes the proliferation of microglia, while TGF-β promotes both proliferation and inhibition of cell death of microglia. However, upon comparing the most effective doses of both (assessed from the proliferation assay), we identified no statistically significant difference between the two factors in terms of cell death; thus, both have a proliferative effect on microglial cells. In addition, a TGF-β receptor 1 inhibitor, galunisertib, caused marked inhibition of proliferation in a dose-dependent manner, indicating that inhibition of TGF-β signalling reduces the proliferation of microglia. Therefore, galunisertib may represent a promising therapeutic agent for the treatment of neurodegenerative diseases via inhibition of nerve injury-induced microglial proliferation, which may result in reduced inflammatory and neuropathic and cancer pain.
Insights
Transforming growth factor beta (TGF-β) significantly increases microglial proliferation in vitro. Inhibition of TGF-β signaling with galunisertib shows therapeutic potential for neurodegenerative diseases.
Area of Science:
- Neuroscience
- Immunology
- Cell Biology
Background:
- Microglial activation and proliferation are key early indicators of brain pathologies.
- Understanding factors that regulate microglial behavior is crucial for developing treatments for neurological disorders.
Purpose of the Study:
- To identify factors promoting microglial activation and proliferation.
- To investigate the in vitro effects of transforming growth factor beta (TGF-β) on microglial cell lines.
- To evaluate the therapeutic potential of inhibiting TGF-β signaling.
Main Methods:
- Cultured microglial cell lines (EOC 2 and SIM-A9) with various growth factors.
- Assessed cell proliferation, death, and viability.
- Utilized a TGF-β receptor 1 inhibitor, galunisertib, to study signaling pathway effects.
Main Results:
- Transforming growth factor beta (TGF-β) significantly increased in vitro proliferation of both microglial cell lines.
- Both TGF-β and colony-stimulating factor 1 demonstrated proliferative effects on microglia.
- Galunisertib inhibited microglial proliferation in a dose-dependent manner, confirming the role of TGF-β signaling.
Conclusions:
- TGF-β promotes microglial proliferation, and its signaling pathway is critical for this process.
- Inhibiting TGF-β signaling via galunisertib offers a potential therapeutic strategy for neurodegenerative diseases.
- Targeting microglial proliferation may reduce inflammation and pain associated with neurological conditions.
