Disruption of gap junctions reduces biomarkers of decidualization and angiogenesis and increases inflammatory mediators in human endometrial stromal cell cultures

ContextUterine decidualization is critical to embryonic implantation and sustained pregnancy.ObjectiveTo evaluate the role of gap junction intercellular communications and connexin (Cx) proteins in the morphological and biochemical differentiation of decidualized human endometrial stromal cell (ESC) cultures.DesignTranslational cell biological study.SettingAcademic medical center.PatientsEndometrial tissue was provided by five healthy reproductive age women on no hormonal medication, undergoing laparoscopy in the early proliferative phase of the menstrual cycle.InterventionsEndometrial biopsy under general anesthesia, establishment and decidualization of ESC with 10 nM 17β-estradiol, 100 nM progesterone and 0.5 mM dibutyryl-cAMP (E/P/c), and manipulation of gap junctions in vitro via a combination of pharmacological or transgenic approaches.Main outcome measuresDecidualized ESC evaluated morphologically for epithelioid transformation, gap junctions by dye diffusion and Cx43, prolactin, VEGF and IL-6 expression by RT-PCR, Western and ELISA methods.ResultsCx43 accumulation and functional gap junctions between decidualized ESC increase concomitantly with morphological differentiation following E/P/c treatment. Disruption of gap junctions using pharmacological inhibitors or Cx43 shRNA prevents morphological differentiation and inhibits prolactin and VEGF secretion. By contrast, IL-6 secretion from decidualized ESC is augmented by both approaches.ConclusionsThe findings suggest that decidualized ESC function as a coordinated secretory organ to regulate embryonic implantation via intercellular cooperation mediated by gap junctions. When adjacent cells can communicate through these junctions, decidual prolactin and VEGF secretion appears to be optimized for vascular development of the placental bed. Conversely, when intercellular communications are disrupted, angiogenesis is impaired and an inflammatory state is induced.

► Gap junctions and connexin (Cx) proteins facilitate decidual differentiation.
► Human endometrial stromal cells were differentiated in vitro with hormones.
► Gap junction inhibitors and Cx43 shRNA knockdown blocked decidualization.
► Gap junction blockade reduced prolactin and VEGF, but increased IL-6.
► Gap junctions maintain decidual function and prevent inflammation in vitro.