Ecto-nucleotidases distribution in human cyclic and postmenopausic endometrium

Abstract

Extracellular ATP and its hydrolysis product, adenosine, acting through specific receptors collectively named purinergic receptors, regulate female fertility by influencing the endometrial fluid microenvironment. There are four major groups of ecto-nucleotidases that control the levels of extracellular ATP and adenosine and thus their availability at purinergic receptors: ecto-nucleoside triphosphate diphosphohydrolases (E-NTPDases), ecto-nucleotide pyrophosphatase/phospho-diesterases (E-NPPs), ecto-5′-nucleotidase (5′NT), and alkaline phosphatases (APs). The aim of the present work is to characterize the expression and distribution of ecto-nucleotidases in human endometrium along the menstrual cycle and after menopause, to evaluate their potential utility as fertility markers. We examined proliferative, secretory and atrophic endometria from women without endometrial pathology undergoing hysterectomy. We show that the ecto-nucleotidases are mainly present at endometrial epithelia, both luminal and glandular, and that their expression fluctuates along the cycle and also changes after menopause. An important result was identifying NPP3 as a new biological marker of tubal metaplasia. Our results emphasize the relevance of the study of purinergic signaling in human fertility.

Proteomics of the Human Endometrial Glandular Epithelium and Stroma from the Proliferative and Secretory Phases of the Menstrual Cycle1

“…The highest levels of expression are seen in the uterine epithelium and in the seminal vesicles, pointing to its likely importance in reproductive biology [50,57]. Recently the various ecto-nucleases were surveyed in human endometrium, and ENPP3 was found to be specifically elevated in the secretory phase of the menstrual cycle [59]. The increased secretory expression of ENPP3 was recently described to be blunted in a progestin-resistant manner from the eutopic endometrium from women with endometriosis.…”

Purinergic signalling in the reproductive system in health and disease

“…In a later paper, these authors showed that the P2Y 2 receptor is expressed by stromal cells, suggesting that it mediates the expression of the early growth response 1 and inhibits stromal cell viability [77]. The distribution of ecto-nucleotidases in human cyclic and post-menopausic endometrium has been described [8]. Ecto-NPP3 was identified as a new biological marker of tubal metaplasia.…”

Reduced striatal ecto-nucleotidase activity in schizophrenia patients supports the “adenosine hypothesis”

“…Immunohistochemistry experiments were performed as described previously [24] except for the use of 30-μm-thick free-floating slices. Slices were incubated overnight at 4°C with the following anti-human-monoclonal antibodies: CD39 (1:500; Ancell, Minnesota, USA), hN3-B3 S for NTPDase3 (1:500; http://ectonucleotidases-ab.com/) and CD73 (1:50; Hycult biotechnology, Uden, The Netherlands).…”

“…Histochemical localization of ATPase, ADPase, and AMPase activity was carried out using the Wachstein/Meisel lead phosphate method [24][25][26] in cryostat-obtained (30-μm thick) free-floating slices. Enzymatic reaction was measured [27].…”

“…The histochemical localization of AP was addressed by using the method of Gossrau with some modifications [24,28]. Briefly, cryostat-obtained (30-μm thick) free-floating slices were washed twice in 0.1 M Tris-HCl buffer pH 7.4, containing 5 mM MgCl 2 , and then pre-incubated with the same buffer at pH 9.4 for 15 min at RT.…”