Enhancement of apoptotic susceptibility by interleukin-1 beta in human endometrial epithelial cells

Interleukin-1 (IL-1) is considered to be an essential cytokine for embryoni c implantation. Expression of the IL-1 receptor in endometrial luminal epit helium increases maximally in the peri-implantation period, and embryonic i mplantation in mice is blocked by the IL-1 receptor antagonist. However, th e function of IL-1 alone in implantation is still unclear. It has been repo rted that endometrial epithelial cells undergo apoptosis at the implantatio n site. In this study we have investigated the regulatory function of IL-1 in endometrial epithelial apoptosis, using the human endometrial epithelial cell line HHUA, which is susceptible to Fas-mediated apoptosis. The enhanc ement of endometrial apoptosis by IL-1 beta was not accompanied by any incr ease in cell-surface expression of Fas, which suggested that IL-1 beta enha nced the postreceptor apoptotic signals in the activated cells. IL-1 may be a regulator of apoptotic susceptibility in endometrial epithelium in the p eri-implantation period.