Echinacea extracts modulate the production of multiple transcription factors in uninfected cells and rhinovirus-infected cells

Abstract

Extracts of Echinacea purpurea are widely used for the prevention and treatment of common colds, coughs, bronchitis and other upper respiratory infections, many of which are caused by rhinoviruses (RVs). Recent reports have indicated that rhinoviruses can stimulate the release of various pro-inflammatory cytokines and chemokines from cultured nasal and bronchial human epithelial cells, and several transcription factors (TFs) have been implicated in this process. The effects of Echinacea treatment and rhinovirus infection on the activation of a range of transcription factors were evaluated by means of a protein/DNA array analysis. The BEAS-2B cell line was used as the model, and nuclear extracts of uninfected cells and rhinovirus-14 infected cells were examined with and without treatment with one of two chemically different Echinacea extracts. It was found that both Echinacea extracts increased the nuclear content of more than 30 transcription factors, including the 12 pro-inflammatory factors examined, such as NFkB, AP-1, AP-2 and STATs 1-6. Virus infection resulted in a more dramatic increase in these same TFs. However, when RV-infected cells were treated with either of the two Echinacea extracts, TF levels were reduced to low levels, although the pattern of the reductions was different for the two extracts. These results indicate that rhinovirus infection of epithelial cells, and treatment with Echinacea extracts, led to profound effects on numerous transcription factors, which could explain the previously observed modulation of secreted cytokines and chemokines, as well as other signaling pathways. In addition, the results could help to explain the beneficial effects of Echinacea consumption.