IL-15 Regulation in Human Endometrial Stromal Cells

Carolyn L. Dunn, Hilary O. D. Critchley and Rodney W. Kelly

MRC Human Reproductive Sciences Unit (C.L.D., R.W.K.) and Obstetrics and Gynaecology (H.O.D.C.), University of Edinburgh, Centre for Reproductive Biology, Edinburgh EH3 9ET, United Kingdom

Abstract

A greater knowledge of IL-5 regulation within human endometrium is important in understanding key reproductive events and uterine Natural Killer cell function. In the present study, expression of IL-15 mRNA was shown to be up-regulated by both PGE2 and IFN-{gamma} in cultures of human endometrial stromal cells (ESC). Release of IL-15 protein was also shown to be under the control of PGE2 and IFN-{gamma} using an enzyme-linked immunosorbent assay for IL-15. In addition, 8-Bromo cAMP was able to increase IL-15 release from ESCs (P < 0.005) implying the actions of PGE2 may be via this second messenger. Addition of a progestin appeared to enhance these effects. Real-time quantitative PCR has demonstrated an up-regulation in IL-15 mRNA expression in the late secretory phase of the menstrual cycle (P < 0.005) and a progressive rise in IFN-{gamma} expression throughout the secretory phase and into first trimester decidua. These results suggest that IL-15 regulation in the human endometrium is complex and that hormonal control may be indirect.