Chronic medroxyprogesterone acetate (MPA) treatment of human endometrial stromal cells inhibits chemokine gene expression.

Abstract

Objective: It has been proposed that an inflammatory reaction is responsible for the pelvic pain associated with endometriosis. Our laboratory has studied the role of the monocyte chemokine, RANTES (Regulated on Activation, Normal T-cell Expressed and Secreted), as a mediator of this immune response. We hypothesized that the symptomatic relief observed after MPA treatment is associated with inhibition of RANTES gene expression in endometrial stromal cells. Design: Luciferase analysis of chemokine gene promoter and western blot analysis of progesterone receptor in primary human endometrial stromal cell cultures. Materials/Methods: Primary human endometrial stromal cells were prepared and cultured in the absence or presence of up to 100 nM MPA for 2 days (acute treatment) or 8 days (chronic treatment). Human RANTES promoter-luciferase reporter constructs were transiently transfected using previously established conditions that afford a >40% transfection rate. For data normalization and to assure consistent transfection efficiency an internal standard plasmid (renilla luciferase reporter) was co-transfected. Data are expressed as mean ± SD for at least 3 independent experiments and were compared using nonparametric Mann-Whitney statistics. The presence of PR (progesterone receptors) was verified by western blot. Results: Acute treatment (2 days) with 100 nM MPA had no effect on RANTES transcriptional activation. However, in endometrial cells cultured with 100 nM MPA for 8 days, RANTES promoter activation was decreased by 39 ± 17% (p < 0.01). Chronic treatment with MPA increased the two isoforms, PR-A and PR-B in stromal cells, while acute treatment had little effect on receptor concentration. Conclusions: These results provide evidence that chronic, but not acute, progestin-induced changes in endometrial stromal cells result in decreased RANTES gene expression. The presence of PR is consistent with a PR-mediated effect of MPA. This in vitro finding may represent an anti-inflammatory effect in vivo, in part responsible for the amelioration of subjective endometriosis symptoms in women using chronic progestins. Supported By: NIH/NICHD Specialized Cooperative Centers Program in Reproduction Research (U54HD37321).