Expression of Adiponectin Receptors and Its Possible Implication in the Human Endometrium

Abstract

Adiponectin, a pleiotropic cytokine, exerts its effects via the specific receptors AdipoR1 and AdipoR2. Whereas circulating adiponectin concentrations decrease in women with endometriosis and endometrial cancer, possible effects of adiponectin and the presence of the receptors in the endometrium have not been determined. In this study, we examined the expression of adiponectin receptors AdipoR1 and AdipoR2 in the human endometrium and assessed effects of adiponectin in endometrial cells. Expression of AdipoR1 and AdipoR2 in endometrial tissues was evaluated by real-time quantitative PCR, in situ hybridization, and Western blotting. The effects of adiponectin on phosphorylation of AMP-activated protein kinase, a regulator of energy homeostasis, in cultured endometrial stromal cells (ESCs) and epithelial cells (EECs) were studied by Western blotting. The effects of adiponectin on IL-1beta-induced secretion of IL-6, IL-8, and monocyte chemoattractant protein 1 from cultured ESCs were determined using specific ELISAs. The expression of AdipoR1 and AdipoR2 was detected in the endometrium. The expression of both genes was increased in the midluteal phase, the period of embryo implantation. In situ hybridization revealed that both AdipoR1 and AdipoR2 appeared to be equally expressed in the epithelial cells and in the stromal cells. Adiponectin increased phosphorylation of AMP-activated protein kinase in ESCs and EECs. Adiponectin decreased IL-1beta-induced secretion of IL-6, IL-8, and monocyte chemoattractant protein 1 from ESCs. These findings suggest that adiponectin exerts energy-homeostatic and antiinflammatory effects in the endometrium, and these effects might be relevant to pathological and physiological endometrium-related events such as implantation and endometriosis.

The ‘beneficial’ adipokines in reproduction and fertility

“…Adiponectin and 5-aminoimidazole-4-carboxamide-1-b-D-ribofuranoside induce AMP-activated protein kinase phosphorylation in human epithelial and stromal endometrial cells. 54 In explants of human term placenta, interference with the phosphorylation of extracellular signal-regulated kinase 1/2 inhibited adiponectin induction of a number of target genes, including the inflammatory cytokines interleukin-1 and interleukin-6, 58 confirming a role for this pathway in transduction of the signal in the placenta.…”

“…39 In the human endometrium, AdipoR1 and R2 are present in the endometrial and glandular epithelium, as well as in the stromal fibroblasts. 54 Transcript and protein abundance for both receptors was highest during the secretory or progestational phase of the menstrual cycle. 54 Investigations in the placenta demonstrate that both receptors are present in the human and rat placentae.…”

“…54 Transcript and protein abundance for both receptors was highest during the secretory or progestational phase of the menstrual cycle. 54 Investigations in the placenta demonstrate that both receptors are present in the human and rat placentae. 55 In studies of AdipoR2 during gestation, it was reported that human cytotrophoblast and syncytiotrophoblast, as well as endometrial stroma, expressed this form of the receptor.…”

Adiponectin, the controversial hormone

“…Adiponectin and endometrium Adiponectin receptors have been also detected in the endometrium 26 , where it decreases interleukin and chemoattractant production from endometrial stromal cells. Furthermore, patients with endometrial cancer show serum adiponectin levels significantly lower than controls 27 .…”

Adiponectin Serum Level Difference in Women With Endometriotic and Non-Endometriotic Cysts

“…5,6 Adiponektin telah terbukti diekspresikan oleh jaringan endometrium, namun dalam kadar yang jauh lebih rendah dibandingkan adiponektin dalam sirkulasi, dan kadar adiponektin tidak berbeda bermakna selama siklus haid.…”