Testosterone modulates the expression of molecules linked to insulin action and glucose uptake in endometrial cells

Hyperandrogenism and Polycystic ovary syndrome: Effects in pregnancy and offspring development

Polycystic ovary syndrome (PCOS) is one of the major endocrine disorders affecting women of reproductive age. Its etiology remains unclear. It is suggested that environmental factors, and particularly the intrauterine environment, play key roles in PCOS development. Besides the role of androgens in PCOS pathogenesis, exposure to endocrine disruptors, as is Bisphenol A, could also contribute to its development. Although PCOS is considered one of the leading causes of ovarian infertility, many PCOS patients can get pregnant. Some of them by natural conception and others by assisted reproductive technique treatments. As hyperandrogenism (one of PCOS main features) affects ovarian and uterine functions, PCOS women, despite reaching pregnancy, could present high-risk pregnancies, including implantation failure, an increased risk of gestational diabetes, preeclampsia, and preterm birth. Moreover, hyperandrogenism may also be maintained in these women during pregnancy. Therefore, as an altered uterine milieu, including hormonal imbalance, could affect the developing organisms, monitoring these patients throughout pregnancy and their offspring development is highly relevant. The present review focuses on the impact of androgenism and PCOS on fertility issues and pregnancy-related outcomes and offspring development. The evidence suggests that the increased risk of pregnancy complications and adverse offspring outcomes of PCOS women would be due to the factors involved in the syndrome pathogenesis and the related co-morbidities. A better understanding of the involved mechanisms is still needed and could contribute to a better management of these women and their offspring. This article is categorized under: Reproductive System Diseases > Molecular and Cellular Physiology Reproductive System Diseases > Environmental Factors.

Research progress of endometrial receptivity in patients with polycystic ovary syndrome: a systematic review

Polycystic ovary syndrome (PCOS) is a neuroendocrine heterogeneous disease that frequently occurs in women of reproductive age, causing serious damage to the fertility, quality of life, and physical and mental health of patients. The current studies have proved that satisfactory endometrial receptivity is one of the conditions that must be met during the process of spermatovum position, adhesion and invasion, as well as the subsequent blastocyst division and embryo development. Women with PCOS may suffer a series of pathological processes such as changes in the expression levels of hormones and related receptors, imbalances in the proportion of miscellaneous cytokines, insulin resistance, low-grade chronic inflammation and endometrial morphological changes, which will damage endometrial receptivity from various aspects and obstruct fertilized egg nidation and embryonic development, thus causing adverse reproductive health events including infertility and abortion. This article reviews the research progress about characteristics and related influencing factors of endometrial receptivity in PCOS patients.

An Update on the Progress of Endometrial Receptivity in Women with Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a significant public health issue with diverse presentations, including reproductive, metabolic, and psychological disorders. Although problems with ovulation, metabolism, and hormonal imbalance can be pharmacologically improved, even the excellent quality of transferred embryos does not necessarily increase the pregnancy rate. Poor endometrial receptivity in women with PCOS perturbs endometrial decidualization and blastocyst implantation, increasing adverse pregnancy outcomes, such as miscarriage and poor embryonic development. The etiological and pathophysiological mechanisms involved in defective endometrial receptivity in women with PCOS have not been fully elucidated to date. Various contributing factors have been reported as primary causes of defective endometrial receptivity in women with PCOS, including metabolic alterations, inflammatory events, and some abnormally expressed endometrial molecular markers. However, few studies to date have investigated in depth the complex mechanisms underlying the compromised endometrial receptivity in women with PCOS. This article reviews recent reports mainly on metabolic alterations and some new endometrial molecular markers in order to collate the existing data and improve our understanding in this field. The aim was to discuss current novel insights on defective endometrial receptivity in women with PCOS in order to provide a theoretical basis for reducing adverse pregnancy outcomes and improving the live birth rate in PCOS.

Endometrial function in women with polycystic ovary syndrome: a comprehensive review

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common cause of anovulatory infertility. An endometrial component has been suggested to contribute to subfertility and poor reproductive outcomes in affected women.

OBJECTIVE AND RATIONALE

The aim of this review was to determine whether there is sufficient evidence to support that endometrial function is altered in women with PCOS, whether clinical features of PCOS affect the endometrium, and whether there are evidence-based interventions to improve endometrial dysfunction in PCOS women.

SEARCH METHODS

An extensive literature search was performed from 1970 up to July 2020 using PubMed and Web of Science without language restriction. The search included all titles and abstracts assessing a relationship between PCOS and endometrial function, the role played by clinical and biochemical/hormonal factors related to PCOS and endometrial function, and the potential interventions aimed to improve endometrial function in women with PCOS. All published papers were included if considered relevant. Studies having a specific topic/hypothesis regarding endometrial cancer/hyperplasia in women with PCOS were excluded from the analysis.

OUTCOMES

Experimental and clinical data suggest that the endometrium differs in women with PCOS when compared to healthy controls. Clinical characteristics related to the syndrome, alone and/or in combination, may contribute to dysregulation of endometrial expression of sex hormone receptors and co-receptors, increase endometrial insulin-resistance with impaired glucose transport and utilization, and result in chronic low-grade inflammation, immune dysfunction, altered uterine vascularity, abnormal endometrial gene expression and cellular abnormalities in women with PCOS. Among several interventions to improve endometrial function in women with PCOS, to date, only lifestyle modification, metformin and bariatric surgery have the highest scientific evidence for clinical benefit.

WIDER IMPLICATIONS

Endometrial dysfunction and abnormal trophoblast invasion and placentation in PCOS women can predispose to miscarriage and pregnancy complications. Thus, patients and their health care providers should advise about these risks. Although currently no intervention can be universally recommended to reverse endometrial dysfunction in PCOS women, lifestyle modifications and metformin may improve underlying endometrial dysfunction and pregnancy outcomes in obese and/or insulin resistant patients. Bariatric surgery has shown its efficacy in severely obese PCOS patients, but a careful evaluation of the benefit/risk ratio is warranted. Large scale randomized controlled clinical trials should address these possibilities.

Role of gut microbiota in the development of insulin resistance and the mechanism underlying polycystic ovary syndrome: a review

Polycystic ovary syndrome (PCOS) is a complex endocrine and metabolic disorder. Typically, it is characterized by hirsutism, hyperandrogenism, ovulatory dysfunction, menstrual disorders and infertility. To date, its pathogenesis remains unclear. However, insulin resistance (IR) is considered as the primary pathological basis for its reproductive dysfunction. On the other hand, a condition in which insulin is over-secreted is called hyperinsulinemia. IR/Hyperinsulinemia is associated with chronic inflammation, hormonal changes, follicular dysplasia, endometrial receptivity changes, and abortion or infertility. Additionally, it increases incidence of complications during pregnancy and has been associated with anxiety, depression, and other psychological disorders. Gut microbiota, the "second genome" acquired by the human body, can promote metabolism, immune response through interaction with the external environment. Gut microbiota dysbiosis can cause IR, which is closely linked to the occurrence of PCOS. This article reviewed recent findings on the roles of gut microbiota in the development of insulin resistance and the mechanism underlying polycystic ovary syndrome.

Comparative study of testosterone and vitamin D analogue, elocalcitol, on insulin-controlled signal transduction pathway regulation in human skeletal muscle cells

PURPOSE

Skeletal muscle (Skm) plays a key role in regulating energetic metabolism through glucose homeostasis. Several hormones such as Testosterone (T) and Vitamin D (VD) have been shown to affect energy-dependent cell trafficking by determining Insulin (I)-like effects.

AIM

To elucidate possible hormone-related differences on muscular metabolic control, we analyzed and compared the effects of T and elocalcitol (elo), a VD analogue, on the activation of energy-dependent cell trafficking, metabolism-related-signal transduction pathways and transcription of gene downstream targets.

METHODS

Human fetal skeletal muscle cells (Hfsmc) treated with T or elo were analyzed for GLUT4 localization, phosphorylation/activation status of AKT, ERK1/2, IRS-1 signaling and c-MYC protein expression.

RESULTS

T, similar to elo, induced GLUT4 protein translocation likely in lipid raft microdomains. While both T and elo induced a rapid IRS-1 phosphorylation, the following dynamic in phosphorylation/activation of AKT and ERK1/2 signaling was different. Moreover, T but not elo increased c-MYC protein expression.

CONCLUSIONS

All together, our evidence indicates that whether both T and elo are able to affect upstream I-like pathway, they differently determine downstream effects in I-dependent cascade, suggesting diverse physiological roles in mediating I-like response in human skeletal muscle.

Dehydroepiandrosterone-induced activation of mTORC1 and inhibition of autophagy contribute to skeletal muscle insulin resistance in a mouse model of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in women of reproductive age and also an important metabolic disorder associated with insulin resistance (IR). Hyperandrogenism is a key feature of PCOS. However, whether hyperandrogenism can cause IR in PCOS remains largely unknown. The mammalian target of rapamycin complex 1 (mTORC1) and its regulated autophagy are closely associated with IR. In the present study, we investigated the role of mTORC1-autophagy pathway in skeletal muscle IR in a dehydroepiandrosterone (DHEA)-induced PCOS mouse model. DHEA-treated mice exhibited whole-body and skeletal muscle IR, along with the activated mTORC1, repressed autophagy, impaired mitochondria, and reduced plasma membrane glucose transporter 4 (GLUT4) expression in skeletal muscle of the mice. In cultured C2C12 myotubes, treatment with high dose testosterone activated mTORC1, reduced autophagy, impaired mitochondria, decreased insulin-stimulated glucose uptake, and induced IR. Inhibition of mTORC1 or induction of autophagy restored mitochondrial function, up-regulated insulin-stimulated glucose uptake, and increased insulin sensitivity. On the contrary, inhibition of autophagy exacerbated testosterone-induced impairment. Our findings suggest that the mTORC1-autophagy pathway might contribute to androgen excess-induced skeletal muscle IR in prepubertal female mice by impairing mitochondrial function and reducing insulin-stimulated glucose uptake. These data would help understanding the role of hyperandrogenism and the underlying mechanism in the pathogenesis of skeletal muscle IR in PCOS.

Emerging role for dysregulated decidualization in the genesis of preeclampsia

In normal human placentation, uterine invasion by trophoblast cells and subsequent spiral artery remodeling depend on cooperation among fetal trophoblasts and maternal decidual, myometrial, immune and vascular cells in the uterine wall. Therefore, aberrant function of anyone or several of these cell-types could theoretically impair placentation leading to the development of preeclampsia. Because trophoblast invasion and spiral artery remodeling occur during the first half of pregnancy, the molecular pathology of fetal placental and maternal decidual tissues following delivery may not be informative about the genesis of impaired placentation, which transpired months earlier. Therefore, in this review, we focus on the emerging prospective evidence supporting the concept that deficient or defective endometrial maturation in the late secretory phase and during early pregnancy, i.e., pre-decidualization and decidualization, respectively, may contribute to the genesis of preeclampsia. The first prospectively-acquired data directly supporting this concept were unexpectedly revealed in transcriptomic analyses of chorionic villous samples (CVS) obtained during the first trimester of women who developed preeclampsia 5 months later. Additional supportive evidence arose from investigations of Natural Killer cells in first trimester decidua from elective terminations of women with high resistance uterine artery indices, a surrogate for deficient trophoblast invasion. Last, circulating insulin growth factor binding protein-1, which is secreted by decidual stromal cells was decreased during early pregnancy in women who developed preeclampsia. We conclude this review by making recommendations for further prospectively-designed studies to corroborate the concept of endometrial antecedents of preeclampsia. These studies could also enable identification of women at increased risk for developing preeclampsia, unveil the molecular mechanisms of deficient or defective (pre)decidualization, and lead to preventative strategies designed to improve (pre)decidualization, thereby reducing risk for preeclampsia development.

Metabolic actions of insulin in ovarian granulosa cells were unaffected by hyperandrogenism

Polycystic ovary syndrome (PCOS) patients have intra-ovarian hyperandrogenism and granulosa cells (GCs) from PCOS patients have impaired insulin-dependent glucose metabolism and insulin resistance. The purpose of this study is to determine whether excess androgen affects glucose metabolism and induces insulin resistance of GCs. We firstly explored the insulin metabolic signaling pathway and glucose metabolism in cultured GCs. The Akt phosphorylation and lactate production were increased after insulin treatment. Pre-treatment with PI3-K inhibitor attenuated insulin-induced phosphorylation of Akt and lactate accumulation. However, after treating GCs with different concentrations of testosterone for 5 days, insulin-induced phosphorylation of Akt and lactate production showed no significant change comparing with those of control cells. Finally, mRNA expression of insulin signaling mediators including INSR, IRS-1, IRS-2, and GLUT-4 in GCs was also not significantly altered after testosterone treatment. In conclusion, insulin activates PI3-K/Akt signaling pathway and promotes lactate production in ovarian GCs, but high androgen exerted no obvious influence on insulin signaling pathway and metabolic effect in GCs, suggesting that metabolic actions of insulin in ovarian GCs were unaffected by hyperandrogenism directly.

Polycystic ovary syndrome: Endometrial markers

Women with polycystic ovarian syndrome (PCOS) present with several endometrial abnormalities possibly explaining some of the adverse endometrium-related outcomes in these women. PCOS and an increased miscarriage rate have been suggested to coincide, but the results are conflicting. Recent studies have also shown increased risks of pregnancy-induced hypertension, preeclampsia, and premature delivery that may be related to altered decidualization/placentation in affected women. In the long run, PCOS per se is associated with the occurrence of endometrial cancer (EC), with obesity aggravating the risk. Most investigated markers of the endometrial abnormalities in women with PCOS are related to steroid hormone action (ERs (estrogen receptors), PRs (progesterone receptors), ARs (androgen receptors), and steroid receptor coactivators), endometrial receptivity/decidualization (HOXA10, αvβ3 integrin, and IGFBP-1 (insulin-like growth factor-binding protein 1)), glucose metabolism (IRs (insulin receptors), glucose transporters, IGFs) and inflammation/immune cell migration ((IL-6 (interleukin 6), CCL2 (CC motif ligand), and uNK (uterine natural killer) cells). Despite several endometrial abnormalities in women with PCOS, the clinical relevance of these findings still awaits future clarification; to date, no common screening protocols/recommendations for women with PCOS have been established.

Hyperandrogenism Decreases GRP78 Protein Level and Glucose Uptake in Human Endometrial Stromal Cells

BACKGROUND

Women with polycystic ovary syndrome (PCOS) exhibit a low fertility by chronic hyperandrogenemia. Different evidence have shown that androgens could regulate the endoplasmic reticulum (ER) homeostasis and glucose metabolism. However, it is unclear whether androgens can exert these effects on human endometrial stromal cells. Our goal was to study the protein content of GRP78 (an ER homeostasis marker) in endometria from women with PCOS and healthy women and to assess the GRP78 protein levels and its relationship with glucose uptake on a human endometrial stromal cell line stimulated with testosterone.

METHODS

Immunohistochemistry assays for GRP78 were performed on endometrial samples obtained from women with PCOS (n = 8) and control women subjected to hysterectomy (n = 8). Western blot analysis for GRP78 and glucose uptake was assessed in a telomerase-immortalized human endometrial stromal cell line (T-HESC) exposed to testosterone for 24 or 48 hours and challenged to an insulin short-term stimulation. Tukey test was performed for human samples comparison. Student t test or ANOVA-Bonferroni test was carried out according to the in vitro experiment. P < .05 was considered as significant.

RESULTS

GRP78 stromal immunostaining was reduced in PCOS endometria compared to controls (P < .05). The T-HESC shows a testosterone-dependent downregulation of GRP78 protein content (P < .05), concomitant with half-reduction in glucose uptake compared to controls (P < .05). Moreover, enhanced small interfering RNA against GRP78 messenger RNA leads to a decrease in glucose uptake (P < .05). Such effects were reverted by hydroxyflutamide, an inhibitor of androgen receptor.

CONCLUSION

These results suggest that hyperandrogenemic PCOS environment could compromise the endometrial homeostasis confirmed by the decrease in glucose uptake induced by testosterone and exhibited by stromal cells.

Global gene expression profiling of porcine endometria on Days 12 and 16 of the estrous cycle and pregnancy

The objective of the study was to investigate transcriptomic profile of pig endometrium on Days 12 and 16 of pregnancy in comparison with the respective days of the estrous cycle. Labeled complementary DNA was hybridized to Porcine Long Oligo microarray containing 13,297 oligonucleotide probes, which represented complementary DNA and expressed sequence tags. Statistical analysis revealed 110 differentially expressed genes (DEGs) on Day 12 of pregnancy and 179 DEGs on Day 16 of pregnancy. In silico analysis of gene function and functionality networks revealed links between genes implicated in cell death and survival, protein synthesis, lipid metabolism, cellular movement, tissue development, and cell-to-cell signaling. On Day 12 of pregnancy, estrogen, transforming growth factor (TGF) β1, and fibroblast growth factor (FGF) 2, and on Day 16 of pregnancy, epidermal growth factor (EGF), insulin, interleukin 11 (IL-11), and FGF family members were indicated as possible upstream regulators of several DEGs. Obtained results showed changes in global endometrial gene expression at the time of maternal recognition of pregnancy and embryo implantation. Additionally, these data revealed signaling molecules, which together with E2, may evoke molecular changes in the uterus, leading to successful pregnancy establishment.