[Differential expression of immediately early gene c-fos in THP-1 macrophage subtype polarization]

Objective: To investigate the expression of immediate early gene c-fos in THP-1 macrophage subtype polarization. Methods: PMA was used to induce the polarization of THP-1 monocytes to macrophages, and the expression of c-fos in the polarization process was observed. After PMA treatment, LPS or IL-4 were used alone to induce the polarization of THP-1 macrophages to the M1 or M2 subtypes. Subsequently, real-time quantitative PCR and western-blot were used to analyze the changes in the expressions of the cell subtype markers CD274, CD86 and CD163. Meanwhile, the expression of c-fos in the polarization process was observed dynamically. Results: The levels of c-fos protein and mRNA expressions were up-regulated during PMA-induced polarization of THP-1 monocytes. The protein and mRNA expressions of c-fos were significantly decreased during the polarization of THP-1 cells into M1 macrophages induced by LPS. The specific markers showed the characteristics of M1 macrophages polarization at 24 h (CD86 protein increased, CD274 and CD163 protein decreased). The protein and mRNA expressions of c-fos were significantly increased during the polarization of THP-1 cells into M2 macrophages induced by IL-4. The specific markers showed the characteristics of M2 macrophages polarization at 24 h (CD86 protein decreased, CD274 and CD163 protein increased). Conclusion: C-fos plays an important role in the polarization of THP-1 monocytes to macrophages. Moreover, it may be involved in the regulation of macrophage subtype polarization, by inhibiting the formation of M1 macrophage and promoting the polarization of macrophages to the M2 subtype.