Glycyrrhizin improves the antimicrobial peptide production by human epidermal keratinocytes (NHEK) transwell-cultured with peripheral blood linage- CD34+ cells, a suppressor cell on the antimicrobial peptide production by NHEK (134.46)

Abstract Previously, linage- CD34+ cells isolated form burn patient peripheral blood cells were shown to be inhibitory on the antimicrobial peptide production by NHEK. In the present study, the effect of glycyrrhizin (GL) on the CD34+ suppressor cell activity for the production of β-defensin 1 (BD-1) by NHEK was determined. Linage- CD34+ cells were isolated from peripheral blood of healthy donors after 1-hr of programmed exercise, as previously described. CD34+ cells (1 x 105 cells/ml, upper chamber) were transwell-cultured with NHEK (1 x 105 cells/ml, lower chamber) in the presence or absence of GL (Minophagen Pharmaceutical Co., Ltd., Tokyo, Japan). Forty-eight hrs after cultivation, cells in the lower chamber were assayed for human BD-1 and cathelicidin (CAP-18) mRNAs by RT-PCR. BD-1 and CAP-18 mRNAs were consistently expressed by NHEK. However, NHEK transwell-cultured with CD34+ cells did not express these peptide mRNAs. When transwell-cultures between these 2 cells were performed in the presence of 100 μg/ml of GL, mRNAs for BD-1 and CAP-18 were expressed by NHEK. The mRNA expression for BD-1 and CAP-18 by NHEK was not directly influenced by GL. These results indicate that the suppressor cell activity of linage- CD34+ cells on the antimicrobial peptide production by NHEK is modulated by GL. This study was supported by SHC NA #8610.