Calcium ionophore A23187 induces interleukin-8 gene expression and protein secretion in human monocytic cells

Area of Science:

• Immunology
• Molecular Biology
• Cell Biology

Background:

• Interleukin-8 (IL-8) is a key chemokine involved in inflammatory responses.
• Understanding the regulation of IL-8 gene expression is crucial for developing targeted therapies.

Purpose of the Study:

• To investigate the regulatory mechanisms of interleukin-8 (IL-8) gene expression in human monocytic cell lines.
• To determine the role of intracellular calcium in IL-8 production.

Main Methods:

• Human monocytic cell lines (THP-1, U937) were treated with various agents including IL-1, IFN-gamma, LPS, PMA, and the calcium ionophore A23187.
• Gene expression was assessed by Northern blotting to detect IL-8 mRNA levels.
• Protein synthesis and secretion were evaluated using immunofluorescence and ELISA.

Main Results:

• IL-1 and IFN-gamma did not induce significant IL-8 expression.
• LPS or PMA alone resulted in suboptimal IL-8 mRNA induction.
• Combined PMA and LPS treatment enhanced IL-8 mRNA levels.
• The calcium ionophore A23187 consistently increased IL-8 gene expression, protein synthesis, and secretion.

Conclusions:

• Increases in intracellular calcium are a significant trigger for IL-8 gene expression.
• Calcium ionophore-induced IL-8 production involves both mRNA induction and subsequent protein synthesis and secretion.
• These findings highlight the critical role of calcium signaling in modulating IL-8 production in monocytic cells.