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Published on: August 15, 2012
Retinoic acid enhances the secretion of plasminogen from cultured rat microglia
K Nakajima1, N Takemoto, S Kohsaka
1Department of Neurochemistry, National Institute of Neuroscience, Tokyo, Japan.
Abstract:
To determine the amount of plasminogen in microglial conditioned medium, a highly sensitive and specific enzyme-linked immunosorbent assay (ELISA) for rat plasminogen was established. Weak cross-reactivity with human serum plasminogen was observed, while no reactivity was detected with frog and carp plasminogen. The specificity of the immunosorbent assay was confirmed by Western blotting. The secretion of plasminogen into the microglial culture medium was quantified by using the established ELISA and was found to be increased depending on the culture time and number of microglia. The secretion was increased about 5-fold by stimulation with retinoic acid, while interleukin-1, and basic fibroblast growth factor showed no significant effect.
Insights
Researchers developed a sensitive assay to measure plasminogen in microglial conditioned medium. Plasminogen secretion increased with culture time and cell number, and was significantly boosted by retinoic acid.
Area of Science:
- Neuroscience
- Immunology
- Biochemistry
Background:
- Microglia play crucial roles in the central nervous system.
- Understanding microglial function requires analyzing secreted factors.
- Plasminogen is a key protein in the fibrinolytic system with potential roles in neuroinflammation.
Purpose of the Study:
- To establish a sensitive and specific enzyme-linked immunosorbent assay (ELISA) for quantifying rat plasminogen.
- To investigate the secretion of plasminogen by primary microglia in vitro.
- To determine factors influencing plasminogen secretion, including retinoic acid, interleukin-1, and basic fibroblast growth factor.
Main Methods:
- Development and validation of a rat plasminogen-specific ELISA.
- Western blotting to confirm assay specificity.
- Culturing primary microglia and collecting conditioned medium.
- Quantifying plasminogen levels using the developed ELISA under various conditions.
Main Results:
- A highly sensitive and specific ELISA for rat plasminogen was successfully established.
- Plasminogen secretion by microglia increased with culture time and cell density.
- Retinoic acid significantly upregulated plasminogen secretion (approximately 5-fold).
- Interleukin-1 and basic fibroblast growth factor did not significantly affect plasminogen secretion.
Conclusions:
- The developed ELISA is a reliable tool for measuring plasminogen in microglial conditioned medium.
- Microglia actively secrete plasminogen, and this secretion is modulated by specific stimuli.
- Retinoic acid is a potent stimulator of microglial plasminogen secretion, suggesting a role in modulating the neuroinflammatory environment.
