Changes in expression and activity levels of ecto-5'-nucleotidase/CD73 along the mouse female estrous cycle

Extracellular nucleotides in smooth muscle contraction

Extracellular nucleotides and nucleosides are crucial signalling molecules, eliciting diverse biological responses in almost all organs and tissues. These molecules exert their effects by activating specific nucleotide receptors, which are finely regulated by ectonucleotidases that break down their ligands. In this comprehensive review, we aim to elucidate the relevance of extracellular nucleotides as signalling molecules in the context of smooth muscle contraction, considering the modulatory influence of ectonucleotidases on this intricate process. Specifically, we provide a detailed examination of the involvement of extracellular nucleotides in the contraction of non-vascular smooth muscles, including those found in the urinary bladder, the airways, the reproductive system, and the gastrointestinal tract. Furthermore, we present a broader overview of the role of extracellular nucleotides in vascular smooth muscle contraction.

Discovering lethal alleles across the turkey genome using a transmission ratio distortion approach

Deviation from Mendelian inheritance expectations (transmission ratio distortion, TRD) has been observed in several species, including the mouse and humans. In this study, TRD was characterized in the turkey genome using both allelic (specific- and unspecific-parent TRD) and genotypic (additive- and dominance-TRD) parameterizations within a Bayesian framework. In this study, we evaluated TRD for 23 243 genotyped Turkeys across 56 393 autosomal SNPs. The analyses included 500 sires, 2013 dams and 11 047 offspring (trios). Three different haplotype sliding windows of 4, 10 and 20 SNPs were used across the autosomal chromosomes. Based on the genotypic parameterizations, 14 haplotypes showed additive and dominance TRD effects highlighting regions with a recessive TRD pattern. In contrast, the allelic model uncovered 12 haplotype alleles with the allelic TRD pattern which showed an underrepresentation of heterozygous offspring in addition to the absence of homozygous animals. For regions with the allelic pattern, only one particular region showed a parent-specific TRD where the penetrance was high via the dam, but low via the sire. The gene set analysis uncovered several gene ontology functional terms, Reactome pathways and several Medical Subject Headings that showed significant enrichment of genes associated with TRD. Many of these gene ontology functional terms (e.g. mitotic spindle assembly checkpoint, DRM complex and Aneuploidy), Reactome pathways (e.g. Mismatch repair) and Medical Subject Headings (e.g. Adenosine monophosphate) are known to be related to fertility, embryo development and lethality. The results of this study revealed potential novel candidate lethal haplotypes, functional terms and pathways that may enhance breeding programs in Turkeys through reducing mortality and improving reproduction rate.

Blastocyst-induced ATP release from luminal epithelial cells initiates decidualization through the P2Y2 receptor in mice

Embryo implantation involves a sterile inflammatory reaction that is required for the invasion of the blastocyst into the decidua. Adenosine triphosphate (ATP) released from stressed or injured cells acts as an important signaling molecule to regulate many key physiological events, including sterile inflammation. We found that the amount of ATP in the uterine luminal fluid of mice increased during the peri-implantation period, and this depended on the presence of an embryo. We further showed that the release of ATP from receptive epithelial cells was likely stimulated by lactate released from the blastocyst through connexin hemichannels. The ATP receptor P2y2 was present on uterine epithelial cells during the preimplantation period and increased in the stromal cells during the time at which decidualization began. Pharmacological inhibition of P2y2 compromised decidualization and implantation. ATP-P2y2 signaling stimulated the phosphorylation of Stat3 in uterine luminal epithelial cells and the expression of early growth response 1 (Egr1) and prostaglandin-endoperoxide synthase 2 (Ptgs2, also known as Cox-2), all of which are required for decidualization and/or implantation, in stromal cells. Short exposure to high concentrations of ATP promoted decidualization of primary stromal cells, but longer exposures or lower ATP concentrations did not. The expression of genes encoding ATP-degrading ectonucleotidases increased in the decidua during the peri-implantation period, suggesting that they may limit the duration of the ATP signal. Together, our results indicate that the blastocyst-induced release of ATP from uterine epithelial cells during the peri-implantation period may be important for the initiation of stromal cell decidualization.

Impaired Expression of Ectonucleotidases in Ectopic and Eutopic Endometrial Tissue Is in Favor of ATP Accumulation in the Tissue Microenvironment in Endometriosis

Endometriosis is a prevalent disease defined by the presence of endometrial tissue outside the uterus. Adenosine triphosphate (ATP), as a proinflammatory molecule, promotes and helps maintain the inflammatory state of endometriosis. Moreover, ATP has a direct influence on the two main symptoms of endometriosis: infertility and pain. Purinergic signaling, the group of biological responses to extracellular nucleotides such as ATP and nucleosides such as adenosine, is involved in the biology of reproduction and is impaired in pathologies with an inflammatory component such as endometriosis. We have previously demonstrated that ectonucleotidases, the enzymes regulating extracellular ATP levels, are active in non-pathological endometria, with hormone-dependent changes in expression throughout the cycle. In the present study we have focused on the expression of ectonucleotidases by means of immunohistochemistry and in situ activity in eutopic and ectopic endometrial tissue of women with endometriosis, and we compared the results with endometria of women without the disease. We have demonstrated that the axis CD39-CD73 is altered in endometriosis, with loss of CD39 and CD73 expression in deep infiltrating endometriosis, the most severe, and most recurring, endometriosis subtype. Our results indicate that this altered expression of ectonucleotidases in endometriosis boosts ATP accumulation in the tissue microenvironment. An important finding is the identification of the nucleotide pyrophophatase/phosphodiesterase 3 (NPP3) as a new histopathological marker of the disease since we have demonstrated its expression in the stroma only in endometriosis, in both eutopic and ectopic tissue. Therefore, targeting the proteins directly involved in ATP breakdown could be an appropriate approach to consider in the treatment of endometriosis.

Early Life Stress Delays Sexual Maturation in Female Mice

In humans, some forms of early life stress (ELS) have been linked with precocious puberty, altered brain maturation, and increased risk for a variety of forms of pathology. Interestingly, not all forms of ELS have been found to equally impact these metrics of maturation. In recent work, we have found that ELS in the form of limited bedding (LB) from P4 to P11, was associated with precocious hippocampus maturation in males and increased risk for depressive-like pathology and attentional disturbance in female mice. Here, we sought to test whether ELS in the form of LB also impacted the timing of sexual maturation in female mice. To establish rate of somatic and sexual development, distinct cohorts of mice were tested for weight gain, timing of vaginal opening, and development of estrous cycling. ELS animals weighed significantly less than controls at every timepoint measured. Onset of vaginal opening was tracked from P21 to 40, and ELS was found to significantly delay the onset of vaginal opening. To test the impact of ELS on estrous cycle duration and regularity, vaginal cytology was assessed in independent groups of animals using either a continuous sampling (daily from P40 to P57) or random sampling approach (single swab at P35, P50, or P75). ELS did impact measures of estrous cycling, but these effects were dependent upon the sampling method used. We also tested the impact of ELS on anxiety-like behaviors over development and across the estrous cycle. We observed a developmental increase in anxiety-like behavior in control but not ELS mice. No effect of estrous cycle stage was found on anxiety-like behavior for either group of mice. Together these results provide evidence that ELS in the form of LB delays somatic and sexual development. Additional work will be required to determine the mechanism by which ELS impacts these measures, and if these effects are common to other models of ELS in rodents.

Mechanism of luminal ATP activated chloride secretion in a polarized epithelium

There are both secretory and absorptive pathways working in tandem to support ionic movement driving fluid secretion across epithelia. The mechanisms exerting control of fluid secretion in the oviduct is yet to be fully determined. This study explored the role of apical or luminal extracellular ATP (ATPe)-stimulated ion transport in an oviduct epithelium model, using the Ussing chamber short-circuit current (Isc) technique. Basal Isc in oviduct epithelium in response to apical ATPe comprises both chloride secretion and sodium absorption and has distinct temporal phases. A rapid transient peak followed by a sustained small increase above baseline. Both phases of the apical ATPe Isc response are sensitive to anion (HCO3-, Cl-) and cation (Na+) replacement. Additionally, the role of apical chloride channels, basolateral potassium channels and intracellular calcium in supporting the peak Isc current was confirmed. The role of ATP breakdown to adenosine resulting in the activation of P2 receptors was supported by examining the effects of non-hydrolyzable forms of ATP. A P2YR2 potency profile of ATP = UTP > ADP was generated for the apical membrane, suggesting the involvement of the P2YR2 subtype of purinoceptor. A P2X potency profile of ATP = 2MeSATP > alpha,beta-meATP > BzATP was also generated for the apical membrane. In conclusion, these results provide strong evidence that purinergic activation of apical P2YR2 promotes chloride secretion and is thus an important factor in fluid formation by the oviduct.

Intravenous Infusion of Nucleated Peripheral Blood Cells Restores Fertility in Mice with Chemotherapy-Induced Premature Ovarian Failure

Cancer treatment with specific chemotherapeutic agents has been well documented to have an adverse impact on female fertility leading to premature ovarian failure (POF). The objective of this study is to investigate if chemotherapeutic induced POF can be reversed by the infusion of autologous nucleated peripheral blood cells (PBMC). To reach our goal, mice were treated with a single intraperitoneal injections of busulfan and cyclophosphamide to induce POF. This was followed by transfusion of PBMC. The ovarian morphology and functional parameters were monitored by radioimmunoassay, real-time PCR, immunofluorescence and immunohistochemistry analysis. Our study showed that chemotherapy (CTX) protracted estrous cycle period and repressed E2 production. In addition, CTX decreased the expressions of steroidogenesis markers, CYP-17 synthesis, StAR (steroidogenic acute regulatory protein), and Connexin-43 protein expression in the ovarian follicles. We also observed reduced numbers and sizes of the primordial and primary follicles in CTX-treated mice compared to untreated controls (p < 0.05). When both CTX and untreated control groups were stimulated with gonadotrophin, the control group produced ten times more ova than the CTX group. Finally, the treatment of premature ovarian failure induced by CTX with autologous PBMC transfusion resulted in over-expression and a statistically significant increase in several stem cell markers and restoration of fertility. Infusion with PBMC in CTX further decreased the estrous cycle length by 2.5 times (p < 0.01). We found that transfusion of autologous PBMC to mice with chemotherapy induced POF was very effective at restoring fertility. These results are similar to other studies using bone marrow derived mesenchymal stem cells.

Early life stress impairs contextual threat expression in female, but not male, mice

Early life stress (ELS) is associated with altered processing of threat signals, and increased lifetime risk of anxiety and affective pathology, disorders that disproportionately affect females. We tested the impact of a limited bedding paradigm of ELS (from P4-11) on contextual threat learning, context memory, footshock sensitivity, and anxietylike behavior, in adult male and female mice. To examine contextual threat learning, mice conditioned by context/footshock association were tested 24 hr later for the context memory. To determine the effect of ELS on footshock sensitivity, a separate cohort of mice were exposed to footshocks of increasing intensity (0.06 to 0.40 mA) and behavioral responses (jump and audible vocalization) were assessed by observers blind to treatment condition, sex, and cycle stage. ELS impaired context memory in female, but not male, mice. ELS increased footshock-induced threshold to vocalize, but not to jump, in both sexes. In female mice, this effect was most apparent during estrus. Decreased body weight, indicative of higher stress incurred by an individual mouse, correlated with increased threshold to jump in both sexes reared in ELS, and to audibly vocalize in ELS females. As ELS effects on shock sensitivity were present in both sexes, the contextual recall deficit in females was not likely driven by changes in the salience of aversive footshocks. No effects on anxietylike behavior, as measured in the elevated plus maze (EPM), were observed. More work is needed to better understand the impact of ELS on both somatic and gonadal development, and their potential contribution to threat learning. (PsycINFO Database Record

Loss of CD73-mediated actin polymerization promotes endometrial tumor progression

Ecto-5'-nucleotidase (CD73) is central to the generation of extracellular adenosine. Previous studies have highlighted a detrimental role for extracellular adenosine in cancer, as it dampens T cell-mediated immune responses. Here, we determined that, in contrast to other cancers, CD73 is markedly downregulated in poorly differentiated and advanced-stage endometrial carcinoma compared with levels in normal endometrium and low-grade tumors. In murine models, CD73 deficiency led to a loss of endometrial epithelial barrier function, and pharmacological CD73 inhibition increased in vitro migration and invasion of endometrial carcinoma cells. Given that CD73-generated adenosine is central to regulating tissue protection and physiology in normal tissues, we hypothesized that CD73-generated adenosine in endometrial carcinoma induces an innate reflex to protect epithelial integrity. CD73 associated with cell-cell contacts, filopodia, and membrane zippers, indicative of involvement in cell-cell adhesion and actin polymerization-dependent processes. We determined that CD73-generated adenosine induces cortical actin polymerization via adenosine A1 receptor (A1R) induction of a Rho GTPase CDC42-dependent conformational change of the actin-related proteins 2 and 3 (ARP2/3) actin polymerization complex member N-WASP. Cortical F-actin elevation increased membrane E-cadherin, β-catenin, and Na(+)K(+) ATPase. Together, these findings reveal that CD73-generated adenosine promotes epithelial integrity and suggest why loss of CD73 in endometrial cancer allows for tumor progression. Moreover, our data indicate that the role of CD73 in cancer is more complex than previously described.

Ecto-nucleotidases activities in the contents of ovarian endometriomas: potential biomarkers of endometriosis

Endometriosis, defined as the growth of endometrial tissue outside the uterus, is a common gynecologic condition affecting millions of women worldwide. It is an inflammatory, estrogen-dependent complex disorder, with broad symptomatic variability, pelvic pain, and infertility being the main characteristics. Ovarian endometriomas are frequently developed in women with endometriosis. Late diagnosis is one of the main problems of endometriosis; thus, it is important to identify biomarkers for early diagnosis. The aim of the present work is to evaluate the ecto-nucleotidases activities in the contents of endometriomas. These enzymes, through the regulation of extracellular ATP and adenosine levels, are key enzymes in inflammatory processes, and their expression has been previously characterized in human endometrium. To achieve our objective, the echo-guided aspirated fluids of endometriomas were analyzed by evaluating the ecto-nucleotidases activities and compared with simple cysts. Our results show that enzyme activities are quantifiable in the ovarian cysts aspirates and that endometriomas show significantly higher ecto-nucleotidases activities than simple cysts (5.5-fold increase for ATPase and 20-fold for ADPase), thus being possible candidates for new endometriosis biomarkers. Moreover, we demonstrate the presence of ecto-nucleotidases bearing exosomes in these fluids. These results add up to the knowledge of the physiopathologic mechanisms underlying endometriosis and, open up a promising new field of study.

Purinergic signalling in the reproductive system in health and disease

There are multiple roles for purinergic signalling in both male and female reproductive organs. ATP, released as a cotransmitter with noradrenaline from sympathetic nerves, contracts smooth muscle via P2X1 receptors in vas deferens, seminal vesicles, prostate and uterus, as well as in blood vessels. Male infertility occurs in P2X1 receptor knockout mice. Both short- and long-term trophic purinergic signalling occurs in reproductive organs. Purinergic signalling is involved in hormone secretion, penile erection, sperm motility and capacitation, and mucous production. Changes in purinoceptor expression occur in pathophysiological conditions, including pre-eclampsia, cancer and pain.

High expression of ecto-nucleotidases CD39 and CD73 in human endometrial tumors

One of the strategies used by tumors to evade immunosurveillance is the accumulation of extracellular adenosine, which has immunosupressive and tumor promoting effects. The study of the mechanisms leading to adenosine formation at the tumor interstitium are therefore of great interest in oncology. The dominant pathway generating extracellular adenosine in tumors is the dephosphorylation of ATP by ecto-nucleotidases. Two of these enzymes acting sequentially, CD39 and CD73, efficiently hydrolyze extracellular ATP to adenosine. They have been found to play a crucial role in a variety of tumors, but there were no data concerning endometrial cancer, the most frequent of the invasive tumors of the female genital tract. The aim of the present work is to study the expression of CD39 and CD73 in human endometrial cancer. We have analyzed protein and gene expression, as well as enzyme activity, in type I endometrioid adenocarcinomas and type II serous adenocarcinomas and their nonpathological endometrial counterparts. High levels of both enzymes were found in tumor samples, with significantly increased expression of CD39 in type II serous tumors, which also coincided with the higher tumor grade. Our results reinforce the involvement of the adenosinergic system in cancer, emphasizing the relevance of ecto-nucleotidases as emerging therapeutic targets in oncology.

Successful induction of stress urinary incontinence in mice by vaginal distension does not depend on the estrous cycle

OBJECTIVE

To determine if the performance of vaginal distension (VD) in different estrous cycle phases affects the successful induction of stress urinary incontinence in mice.

METHODS

Female virgin C57BL/6 mice were distributed into 4 groups according to their estrous cycle phase: proestrus, estrus, metestrus, or diestrus. The estrous cycle was staged by examining vaginal smears, and the method was corroborated by histologic examination of the vagina in a subset of each group. Each group was divided into 4 subgroups for measurement of 24-hour micturition behavior and the leak point pressure (LPP) 4 or 20 days after VD or sham VD.

RESULTS

Voiding events increased and mean void volume decreased 4 days, but not 20 days after VD, and the LPP was decreased 4 days, but not 20 days after VD compared with the corresponding sham group, regardless of the estrous cycle phase when VD was performed. There were no differences in 24-hour micturition behavior or LPP among the 4 different estrous cycle phases either in sham or VD group.

CONCLUSION

Successful induction of reversible stress urinary incontinence in mice is not dependent on the estrous cycle.

Estradiol regulation of nucleotidases in female reproductive tract epithelial cells and fibroblasts

The use of topical and oral adenosine derivatives in HIV prevention that need to be maintained in tissues and cells at effective levels to prevent transmission prompted us to ask whether estradiol could influence the regulation of catabolic nucleotidase enzymes in epithelial cells and fibroblasts from the upper and lower female reproductive tract (FRT) as these might affect cellular TFV-DP levels. Epithelial cells and fibroblasts were isolated from endometrium (EM), endocervix (CX) and ectocervix (ECX) tissues from hysterectomy patients, grown to confluence and treated with or without estradiol prior to RNA isolation. The expression of nucleotidase (NT) genes was measurable by RT-PCR in epithelial cells and fibroblasts from all FRT tissues. To determine if sex hormones have the potential to regulate NT, we evaluated NT gene expression and NT biological activity in FRT cells following hormone treatment. Estradiol increased expression of Cytosolic 5′-nucleotidase after 2 or 4 h in endometrial epithelial cells but not epithelial cells or fibroblasts from other sites. In studies using a modified 5′-Nucleotidase biological assay for nucleotidases, estradiol increased NT activity in epithelial cells and fibroblasts from the EM, CX and ECX at 24 and 48 h. In related studies, HUVEC primary cells and a HUVEC cell line were unresponsive to estradiol in terms of nucleotidase expression or biological activity. Our findings of an increase in nucleotidase expression and biological activity induced by estradiol do not directly assess changes in microbicide metabolism. However, they do suggest that when estradiol levels are elevated during the menstrual cycle, FRT epithelial cells and fibroblasts from the EM, CX and ECX have the potential to influence microbicide levels that could enhance protection of HIV-target cells (CD4+T cells, macrophages and dendritic cells) throughout the FRT.

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

Schizophrenia (SZ) is a major chronic neuropsychiatric disorder characterized by a hyperdopaminergic state. The hypoadenosinergic hypothesis proposes that reduced extracellular adenosine levels contribute to dopamine D2 receptor hyperactivity. ATP, through the action of ecto-nucleotidases, constitutes a main source of extracellular adenosine. In the present study, we examined the activity of ecto-nucleotidases (NTPDases, ecto-5'-nucleotidase, and alkaline phosphatase) in the postmortem putamen of SZ patients (n = 13) compared with aged-matched controls (n = 10). We firstly demonstrated, by means of artificial postmortem delay experiments, that ecto-nucleotidase activity in human brains was stable up to 24 h, indicating the reliability of this tissue for these enzyme determinations. Remarkably, NTPDase-attributable activity (both ATPase and ADPase) was found to be reduced in SZ patients, while ecto-5'-nucleotidase and alkaline phosphatase activity remained unchanged. In the present study, we also describe the localization of these ecto-enzymes in human putamen control samples, showing differential expression in blood vessels, neurons, and glial cells. In conclusion, reduced striatal NTPDase activity may contribute to the pathophysiology of SZ, and it represents a potential mechanism of adenosine signalling impairment in this illness.

Ecto-nucleotidases distribution in human cyclic and postmenopausic endometrium

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.