Positive Health Online

Abstract

MUKERJEE and colleagues, Department of Neuroscience & Center for Neurovirology, School of Medicine, Temple University, 1900 North 12th Street, Philadelphia, PA 19122, USA, have elucidated a mechanism of action of St John' Wort.

Background

St. John's Wort is commonly known for its antiviral, antidepressant, and cytotoxic properties, but traditionally St. John's Wort has also been used to treat inflammation. In this study, we sought to characterize the mechanisms used by St. John's Wort to treat inflammation by examining the effect of the recently isolated protein from St. John's Wort, p27SJ on the expression of MCP-1.

Methodology

Methodology and results: By employing an adenovirus expression vector, we demonstrate that a low concentration of p27SJ upregulates the MCP-1 promoter through the transcription factor C/EBPbeta. In addition, we found that C/EBPbeta-homologous protein (CHOP) or siRNA-C/EBPbeta significantly reduced the ability of p27SJ to activate MCP-1 gene expression. Results from protein-protein interaction studies illustrate the existence of a physical interaction between p27SJ and C/EBPbeta in microglial cells. The use of chromatin immunoprecipitation assay (ChIP) led to the identification of a new cis-element that is responsive to C/EBPbeta within the MCP-1 promoter. Association of C/EBPbeta with MCP-1 DNA was not affected by the presence of p27SJ. The biological activity of MCP-1 produced by cultures of adenovirus-p27SJ transduced cells was increased relative to controls as measured by the transmigration of human Jurkat cells.

Results

Conclusion

Thus, we conclude that at high concentration, p27SJ is a potential agent that may be developed as a modulator of MCP-1 leading to the inhibition of the cytokine-mediated inflammatory responses.

References

Mukerjee R.  Deshmane SL.  Darbinian N.  Czernik M.  Khalili K.  Amini S.  Sawaya BE. St. John's Wort protein, p27SJ, regulates the MCP-1 promoter. Molecular Immunology. 45(15): 4028-35. Sep 2008.