Effects of estradiol on lipopolysaccharide and PaM3CYS stimulation of CCL20/macrophage inflammatory protein 3 alpha and tumor necrosis factor alpha production by uterine epithelial cells in culture

We have previously demonstrated that rat uterine epithelial cells (UEC) produce CCL20/macrophage inflammatory protein 3 alpha (MIP3 alpha) and tumor necrosis factor alpha (TNF-alpha) in response to live and heat-killed Escherichia coli and to the pathogen-associated molecular patterns (PAMP) lipopolysaccharide (LPS) and Pam(3)Cys. To determine whether estradiol (E-2) modulates PAMP-induced CCL20/MIP3 alpha and TNF-alpha secretion, primary cultures of rat UEC were incubated with E-2 for 24 h and then treated with LPS or Pam(3)Cys or not treated for an additional 12 h. E-2 inhibited the constitutive secretion of TNF-alpha and CCL20/MIP3 alpha into culture media. Interestingly, E-2 Pretreatment enhanced CCL20/MIP3 alpha secretion due to LPS and Pam(3)Cys administration. In contrast, and at the same time, E-2 lowered the TNF-alpha response to both PAMP. To determine whether estrogen receptors (ER) mediated the effects of E-2 epithelial cells were incubated with E-2 and/or ICI 182,780, a known ER antagonist. ICI 182,780 had no effect on E-2 inhibition of constitutive TNF-alpha and CCL20/MIP3 alpha secretion. In contrast, ICI 182,780 reversed the stimulatory effect of E-2 on LPS- and/or Pam(3)Cys-induced CCL20/MIP3 alpha secretion as well as partially reversed the inhibitory effect of E-2 on TNF-a production by epithelial cells. Overall, these results indicate that E-2 regulates the production of TNF-alpha and CCL20/MIP3a by UEC in the absence as well as presence of PAMP. Since CCL20/MIP30 alpha has antimicrobial activity and is chemotactic for immune cells, these studies suggest that regulation of CCL20/MIP3 alpha and TNF-alpha by E-2 and PAMP may have profound effects on innate and adaptive immune responses to microbial challenge in the female reproductive tract.