Leptin upregulates β3-integrin expression and interleukin-1β upregulates leptin and leptin receptor expression in human endometrial epithelial cell cultures

Human endometrium and endometrial epithelial cells (EECs) either cultured alone or cocultured with human embryos express leptin and leptin receptor. This study, compares the effect of leptin with that of interleukin-1 beta (IL-1 beta) on the expression of beta3-EEC integrin, a marker of endometrial receptivity. Both cytokines increased the expression of beta3-EEC at concentrations in the range of 0.06-3 nM; however, leptin exhibited a significantly, greater effect than IL-1 beta. We also determined the regulatory effects of IL-1 beta on leptin secretion and ion the expression of leptin and leptin receptor at the protein level in both EEC and endometrial stromal cell (ESC) cultures. In EEC cultures, IL-1 beta upregulated secretion of leptin and expression of both leptin and leptin receptors. No effect of IL-1 beta was found in the ESC cultures. However, leptin exhibited marginal upregulation of leptin receptor. The upregulation of beta3-integrin and leptin/leptin receptor expression by IL-1 beta in EEC cultures indicates that both cytokines may be implicated in embryonic-maternal cross-talk during the early phase of human implantation. Our present data also raise the possibility that leptin is an endometrial molecular effector of IL-1 beta action on beta3-integrin upregulation. Thus, a new role for leptin in human reproduction as an autocrine/paracrine regulator of endometrial receptivity is proposed.