Gonadotropin Hormone Receptor Research Articles

Initiation of Cancer: The Journey From Mutations in Somatic Cells to Epigenetic Changes in Tissue-resident VSELs.

Multiple theories exist to explain cancer initiation, although a consensus on this is crucial for developing effective therapies. 'Somatic mutation theory' suggests that mutations in somatic cells during DNA repair initiates cancer but this concept has several attached paradoxes. Research efforts to identify quiescent cancer stem cells (CSCs) that survive therapy and result in metastasis and recurrence have remained futile. In solid cancers, CSCs are suggested to appear during epithelial-mesenchymal transition by the dedifferentiation and reprogramming of epithelial cells. Pluripotent and quiescent very small embryonic-like stem cells (VSELs) exist in multiple tissues but remain elusive owing to their small size and scarce nature. VSELs are developmentally connected to primordial germ cells, undergo rare, asymmetrical cell divisions and are responsible for the regular turnover of cellsto maintain tissuehomeostasis throughout life. VSELs are directly vulnerable to extrinsic endocrine insults because they express gonadal and gonadotropin hormone receptors. VSELs undergo epigenetic changes due to endocrine insults and transform into CSCs. CSCs exhibit genomic instability and develop mutations due to errors during DNA replication while undergoing excessive proliferation and clonal expansion to formspheroids. Thus tissue-resident VSELs offer a connection between extrinsic insults and variations in cancer incidence reported in various body tissues. To conclude, cancer is indeed a stem cell disease with mutations occurring as a consequence. In addition to immunotherapy, targeting mutations, and Lgr5 + organoids for developing new therapeutics, targeting CSCs (epigenetically altered VSELs) by improving their niche and epigenetic status could serve as a promising strategy to treat cancer.

Tracking conformational transitions of the gonadotropin hormone receptors in a bilayer of (SDPC) poly-unsaturated lipids from all-atom molecular dynamics simulations.

Glycoprotein hormone receptors [thyrotropin (TSHR), luteinizing hormone/chorionic gonadotropin (LHCGR), and follicle stimulating hormone (FSHR) receptors] are rhodopsin-like G protein-coupled receptors. These receptors display common structural features including a prominent extracellular domain with leucine-rich repeats (LRR) stabilized by β-sheets and a long and flexible loop known as the hinge region (HR), and a transmembrane (TM) domain with seven α-helices interconnected by intra- and extracellular loops. Binding of the ligand to the LRR resembles a hand coupling transversally to the α- and β-subunits of the hormone, with the thumb being the HR. The structure of the FSH-FSHR complex suggests an activation mechanism in which Y335 at the HR binds into a pocket between the α- and β-chains of the hormone, leading to an adjustment of the extracellular loops. In this study, we performed molecular dynamics (MD) simulations to identify the conformational changes of the FSHR and LHCGR. We set up a FSHR structure as predicted by AlphaFold (AF-P23945); for the LHCGR structure we took the cryo-electron microscopy structure for the active state (PDB:7FII) as initial coordinates. Specifically, the flexibility of the HR domain and the correlated motions of the LRR and TM domain were analyzed. From the conformational changes of the LRR, TM domain, and HR we explored the conformational landscape by means of MD trajectories in all-atom approximation, including a membrane of polyunsaturated phospholipids. The distances and procedures here defined may be useful to propose reaction coordinates to describe diverse processes, such as the active-to-inactive transition, and to identify intermediaries suited for allosteric regulation and biased binding to cellular transducers in a selective activation strategy.

Reversing Uteropathies Including Cancer-Like Changes in Mice by Transplanting Mesenchymal Stromal Cells or XAR Treatment.

Pluripotent, very small embryonic-like stem cells (VSELs) and tissue-committed 'progenitors' termed endometrial stem cells (EnSCs) are reported in mouse uterus. They express gonadal and gonadotropin hormone receptors and thus are vulnerable to early-life endocrine insults. Neonatal exposure of mouse pups to endocrine disruption cause stem/progenitor cells to undergo epigenetic changes, excessive self-renewal, and blocked differentiation that results in various uteropathies including non-receptive endometrium, hyperplasia, endometriosis, adenomyosis, and cancer-like changes in adult life. Present study investigated reversal of these uteropathies, by normalizing functions of VSELs and EnSCs. Two strategies were evaluated including (i) transplanting mesenchymal stromal cells (provide paracrine support) on D60 or (ii) oral administration of XAR (epigenetic regulator) daily from days 60-100 and effects were studied later in 100 days old mice. Results show normalization of stem/progenitor cells (Oct-4, Oct-4A, Sox-2, Nanog) and Wnt signalling (Wnt-4, β-catenin, Axin-2) specific transcripts. Flow cytometry results showed reduced numbers of 2-6 µm, LIN-CD45-SCA-1 + VSELs. Hyperplasia (Ki67) of epithelial (Pax-8, Foxa-2) and myometrial (α-Sma, Tgf-β) cells was reduced, adenogenesis (differentiation of glands) was restored, endometrial receptivity and differentiation (LIF, c-KIT, SOX-9, NUMB) and stromal cells niche (CD90, VIMENTIN, Pdgfra, Vimentin) were improved, cancer stem cells markers (OCT-4, CD166) were reduced while tumor suppressor genes (PTEN, P53) and epigenetic regulators (Ezh-2, Sirt-1) were increased. To conclude, normalizing VSELs/EnSCs to manage uteropathies provides a novel basis for initiating clinical studies. The study falls under the umbrella of United Nations Sustainable Development Goal 3 to ensure healthy lives and well-being for all of all ages.

AXL/Gas6 signaling mechanisms in the hypothalamic-pituitary-gonadal axis.

AXL is a receptor tyrosine kinase commonly associated with a variety of human cancers. Along with its ligand Gas6 (growth arrest-specific protein 6), AXL is emerging as an important regulator of neuroendocrine development and function. AXL signaling in response to Gas6 binding impacts neuroendocrine structure and function at the level of the brain, pituitary, and gonads. During development, AXL has been identified as an upstream inhibitor of gonadotropin receptor hormone (GnRH) production and also plays a key role in the migration of GnRH neurons from the olfactory placode to the forebrain. AXL is implicated in reproductive diseases including some forms of idiopathic hypogonadotropic hypogonadism and evidence suggests that AXL is required for normal spermatogenesis. Here, we highlight research describing AXL/Gas6 signaling mechanisms with a focus on the molecular pathways related to neuroendocrine function in health and disease. In doing so, we aim to present a concise account of known AXL/Gas6 signaling mechanisms to identify current knowledge gaps and inspire future research.

Candidates for early detection: Effect of pluripotent very small embryonic-like stem cells (VSELs) to transform into cancer stem cells (CSCs) and candidacy for early detection of cancer in a liquid biopsy.

e15024 Background: Prevailing somatic mutation theory (SMT) is mired with several paradoxes and still there is no clarity on how cancer initiates. No distinct pattern of somatic driver mutations specific to cancers affecting solid tissues has yet emerged even after massive NGS studies since 2007. Rather than cancer being a genetic disease, we postulate that endogenous, tissue-resident VSELs get transformed into CSCs to initiate cancer. Under normal conditions, VSELs along with tissue-specific progenitors work in a subtle manner to maintain life-long homeostasis in adult tissues. VSELs express steroid and gonadotropin hormone receptors, are directly vulnerable to environmental insults, and their dysfunction initiates various pathologies, including cancer. Recent mice studies have shown that environmental insults resulted in global hypomethylation, genomic instability and loss of imprinting (LOI) at IGF2/H19 loci that transformed quiescent VSELs into CSCs. Unlike VSELs, CSCs undergo excessive self-renewal, acquire bad-luck mutations during clonal expansion and oncogene activation to initiate cancers, and can also further mobilize to distant sites to cause metastasis. A 1000-sample clinical study based on OCT-4A expression by qRT-PCR suggested that CSCs that get mobilized from affected organs can serve as potential novel candidates for early detection of cancer through liquid biopsy. Methods: CSCs were enriched from the peripheral blood using our proprietary technology. They were enumerated by flow cytometry. VSELs undergo epigenetic changes and LOI to transform into CSCs. TaqMan based qRT-PCR was carried out to study OCT-4A and ALDH-1 positive CSCs and IGF2 expression to monitor LOI at the IGF2/H19 loci. LOI of IGF2 is commonly associated with initiation and also progression of multiple cancers and is also responsible for pushing VSELs out of quiescence and enter the cell cycle as CSCs. Results: Increased numbers of CSCs (epigenetically altered VSELs) were detected in peripheral blood samples of cancer subjects compared to normal subjects (p < 0.0001) by flow cytometry studies. The median absolute count of circulatory VSELs/CSCs was 190 per ml (IQR: 105-295) in normal subjects and 690 per ml (IQR: 370-1265) in cancer subjects. The qRT-PCR study conducted on 100 subjects showed increased expression of OCT-4A, IGF2 and ALDH1 genes in cancer compared to non-cancer subjects. Conclusions: Early detection of cancer by evaluating circulating tumor cells (CTCs) or tumor DNA (ctDNA) holds promise, but their scarce nature and mobilization in late stages only when tumor is > 3 mm in size, are major limitations for widespread translation. Circulating VSELs/CSCs in peripheral blood are evidently promising candidates to screen and classify subjects for cancer absence, likely risk, or presence.

Female-specific pituitary gonadotrope dysregulation in mice with chronic focal epilepsy

Gonadotropin hormone release from the anterior pituitary is critical to regulating reproductive endocrine function. Clinical evidence has documented that people with epilepsy display altered levels of gonadotropin hormones, both acutely following seizures and chronically. Despite this relationship, pituitary function remains a largely understudied avenue in preclinical epilepsy research. Recently, we showed that females in the intrahippocampal kainic acid (IHKA) mouse model of temporal lobe epilepsy displayed changes in pituitary expression of gonadotropin hormone and gonadotropin-releasing hormone (GnRH) receptor genes. Circulating gonadotropin hormone levels, however, have yet to be measured in an animal model of epilepsy. Here, we evaluated the circulating levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), GnRH receptor (Gnrhr) gene expression, and sensitivity to exogenous GnRH in IHKA males and females. Although no changes in overall dynamics of pulsatile patterns of LH release were found in IHKA mice of either sex, estrus vs. diestrus changes in basal and mean LH levels were larger in IHKA females with prolonged, disrupted estrous cycles. In addition, IHKA females displayed increased pituitary sensitivity to GnRH and higher Gnrhr expression. The hypersensitivity to GnRH was observed on diestrus, but not estrus. Chronic seizure severity was not found to be correlated with LH parameters, and FSH levels were unchanged in IHKA mice. These results indicate that although there are changes in pituitary gene expression and sensitivity to GnRH in IHKA females, there may also be compensatory mechanisms that aid in maintaining gonadotropin release in the state of chronic epilepsy in this model.

Loss of Agrp1 in zebrafish: Effects on the growth and reproductive axis

Loss of agouti related neuropeptide (AgRP) does not lead to overt phenotypes in mammals unless AgRP neurons are ablated. In contrast, in zebrafish it has been shown that Agrp1 loss of function (LOF) leads to reduced growth in Agrp1 morphant as well as Agrp1 mutant larvae. Further, it has been shown that multiple endocrine axes are dysregulated upon Agrp1 LOF in Agrp1 morphant larvae. Here we show that adult Agrp1 LOF zebrafish show normal growth and reproductive behavior in spite of a significant reduction in multiple related endocrine axes namely reduced expression in pituitary growth hormone (gh) follicle stimulating hormone (fshb) as well as luteinizing hormone (lhb). We looked for compensatory changes in candidate gene expression but found no changes in growth hormone and gonadotropin hormone receptors that would explain the lack of phenotype. We further looked at expression in the hepatic and muscular insulin-like growth factor (Igf) axis which appears to be normal. Fecundity as well as ovarian histology also appear largely normal while we do see an increase in mating efficiency specifically in fed but not fasted AgRP1 LOF animals. This data shows that zebrafish can grow and reproduce normally in spite of significant central hormone changes and suggests a peripheral compensatory mechanism additional to previously reported central compensatory mechanisms in other zebrafish neuropeptide LOF lines.

A Case-Control Study of the Luteinizing Hormone Level in Luteinizing Hormone Receptor Gene (rs2293275) Polymorphism in Polycystic Ovarian Syndrome Females

Background: Polycystic ovary syndrome (PCOS) is a common heterogeneous disorder characterized by chronic anovulation, infertility, polycystic ovaries, and hyperandrogenic signs. Objective: The aim of this study was to determine the association of luteinizing hormone/chorionic gonadotropin hormone receptor LHCGR polymorphism (rs2293275) with oligomenorrhea, amenorrhea, hirsutism, acne, infertility, LH, LH/FSH ratio, and body mass index (BMI) among PCOS females. Methods: This genetic case-control study recruited 55 PCOS and 55 control females, diagnosed based on the Rotterdam criteria. LH and FSH were measured by the Roche cobas c 502 automated analyzer. Genotypic analysis was carried out using the polymerase chain reaction-restriction fragment length polymorphism and restriction endonuclease digestion. Results: BMI was higher for PCOS patients (28.5 ± 6.59) compared to controls (25.1 ± 5.77), and ovulatory dysfunction was seen among 90% of PCOS females. Oligomenorrhea was common in PCOS (73%), and hirsutism and acne were detected in PCOS (80% and 40%; respectively). LH ≥10 were recoded among 51%, while LH/FSH ≥1.5 was recorded among 33% PCOS females. There is a statistical difference between rs2293275 polymorphism in the AG genotype between PCOS patients and controls. PCOS patients have a significantly higher mean LH level compared to controls (8.36 ± 4.86 and 5.67 ± 2.51, respectively) and showed higher LH/FSH value (1.46 ± 0.81) compared to (0.87 ± 0.30) controls. GG and AG genotypes of LHCGR showed statistically significant higher LH (8.22 ± 4.11; 9.02 ± 3.87) and LH/FSH values (1.57 ± 0.56; 1.64 ± 0.89) compared to controls. Conclusion: LHCGR (rs2293275) GA and GG genetic variants could modulate the hormonal levels of PCOS LH levels and the LH/FSH ratio and associated with hirsutism, oligomenorrhea, BMI, and LH/FSH ratio as risk factors.

The Impact of Luteinizing Hormone/Chorionic Gonadotropin Hormone Receptor Gene Polymorphism rs68073206 in Men with Non-obstructive Azoospermia: A Case-control Study

Background: The functional consequences of the luteinizing hormone/chorionic gonadotropin hormone receptor (LHCGR) gene single nucleotide polymorphism (rs68073206) on male infertility in patients with non-obstructive azoospermia (NOA) is not clear.
 Objective: To examine whether the presence of LHCGR gene; rs68073206 single nucleotide polymorphisms (SNPs) can be associated with incidence of non-obstructive azoospermia.
 Materials and methods: A case-control study comprised of a total of 70 unrelated Iraqi infertile men with non-obstructive azoospermia (zero sperm in semen) whose were on two groups: Group I that were diagnosed to have NOA but didn’t receive infertility treatment yet (33 patient with age of 31.58±1.059 year) and group II that were receiving injectable gonadotropin treatment (37 patient with age of 33.46±1.173 year). In addition to 34 age and BMI matched healthy fertile normozoospermic men (according to the parameters of WHO, 2010). The study population was genotyped by TaqMan assay for LHCGR gene single nucleotide polymorphism (rs68073206). The level of each hormone was estimated by immunoassay technique while the sperm analyses were conducted in accordance with the World Health Organization criteria.
 Results: The study revealed a statistically significant higher hormonal level of serum inhibin B in infertile group I patients with wild GG genotype (246.445±224.106 pg/ml), and the p-value is (0.0439) as compared to that hormone levels of GT and TT genotypes carriers that were (85.969±71.685 pg/ml) and (56.420±23.988 pg/ml) respectively. ). The genotyping variations of patients, whether carrying the homozygous GG, heterozygous GT or homozygous TT genotype, did not reveal a statistically significant difference in distribution as compared to control individuals.
 Conclusions: The LHCGR gene rs68073206 polymorphisms in our population having non-obstructive azoospermia can be suggested to have a modulating potential in variable gonadotropin sensitivity. The detected non-significant difference in genotypic prevalence can be attributable to the limited sample size.

Sodium Fluoride In Vitro Treatment Affects the Expression of Gonadotropin and Steroid Hormone Receptors in Chicken Embryonic Gonads.

Simple SummaryEffects of in vitro sodium fluoride (NaF) treatment on the mRNA expression of luteinizing hormone receptor (LHR), follicle-stimulating hormone receptor (FSHR), estrogen receptors (ESR1 and ESR2), progesterone receptor (PGR), and the immunolocalization of PGRs were examined in gonads of 14-day-old chicken embryos. In the ovary, the NaF treatment significantly increased mRNA levels of all investigated receptors. In the testes, the lowest applied dose of NaF (1.7 mM) significantly decreased the expression of FSHR, ESR1, ESR2, and PGR. Alternatively, the higher NaF dose (7.1 mM) elevated PGR mRNA level in the male gonad. Immunohistochemical analysis revealed that the NaF exposure increased PGR expression in the ovarian cortex, while it decreased its expression in the testes. Collectively, these data indicate that: (i) NaF may disturb the chicken embryonic development, and (ii) different mechanisms of this toxicant action exist within the female and male gonads.Sodium fluoride (NaF), in addition to preventing dental decay may negatively affect the body. The aim of this study was to examine the effect of a 6 h in vitro treatment of gonads isolated from 14-day-old chicken embryos with NaF at doses of 1.7 (D1), 3.5 (D2), 7.1 (D3), and 14.2 mM (D4). The mRNA expression of luteinizing hormone receptor (LHR), follicle-stimulating hormone receptor (FSHR), estrogen receptors (ESR1 and ESR2), progesterone receptor (PGR), and the immunolocalization of progesterone receptors were examined in the tissue. In the ovary, the expression of FSHR and LHR increased following the NaF treatment. In the case of FSHR the highest stimulatory effect was noticed in the D2 group, while the expression of LHR increased in a dose-dependent manner. A gradual increase in ESR1 and PGR mRNA levels was also observed in the ovary following the NaF treatment, but only up to the D3 dose of NaF. The highest ESR2 level was also found in the D3 group. In the testes, the lowest dose of NaF significantly decreased the expression of FSHR, ESR1, ESR2, and PGR. On the other hand, an increase in PGR expression was observed in the D3 group. The expression of LHR in the testes was not affected by the NaF treatment. Immunohistochemical analysis showed that NaF exposure increased progesterone receptor expression in the ovarian cortex, while it decreased its expression in the testes. These results reveal that NaF may disturb the chicken embryonic development and different mechanisms of this toxicant action exist within the females and males.

Impact of Serum Human Chorionic Gonadotropin and Luteinizing Hormone Receptor Expression to Oocyte Maturation Rate: A Study of Controlled Ovarian Stimulation.

Background:Few studies have assessed the impact of serum human chorionic gonadotropin (hCG) levels before oocyte retrieval and luteinizing hormone receptor (LHR) mRNA expression.Aims:The objective was to assess the correlations between serum hCG levels at 12-h posttrigger granulosa cell LHR mRNA expression during the in vitro fertilization (IVF) cycle with oocyte maturation rate and to determine the cutoff level of serum hCG at 12-h posttrigger.Settings and Design:A cross-sectional was conducted for this study at the IVF center of Dr. Cipto Mangunkusumo General Hospital, Jakarta, Indonesia.Materials and Methods:Recombinant follicle-stimulating hormone was used on day 2 of the menstrual cycle with multiple doses of a gonadotropin-releasing hormone antagonist. Recombinant hCG was used to trigger ovulation. At 12-h posttrigger, hCG serum levels were measured using an enzyme-linked immunosorbent assay.Statistical Analysis:Pearson's correlation coefficient was used to evaluate the correlation between oocyte maturation rates, serum hCG levels, and LHR mRNA levels. Cutoff values were determined using a receiver operating characteristic (ROC) curve.Results:Serum hCG levels were positively correlated (r = 0.467;P < 0.01), and LHR mRNA expression was weakly correlated (r = 0.073; P = 0.701) with oocyte maturation. The cutoff of serum hCG for a high maturation rate was 77 mIU/mL, with an area under the ROC curve of 0.765 (95% confidence interval: 0.598–0.939) andP < 0.001.Conclusion:Oocyte maturation is correlated with serum hCG levels with 77 mIU/mL as the cutoff point for oocyte retrieval.

Mechanistic insight into how gonadotropin hormone receptor complexes direct signaling†.

Gonadotropin hormones and their receptors play a central role in the control of male and female reproduction. In recent years, there has been growing evidence surrounding the complexity of gonadotropin hormone/receptor signaling, with it increasingly apparent that the Gαs/cAMP/PKA pathway is not the sole signaling pathway that confers their biological actions. Here we review recent literature on the different receptor-receptor, receptor-scaffold, and receptor-signaling molecule complexes formed and how these modulate and direct gonadotropin hormone-dependent intracellular signal activation. We will touch upon the more controversial issue of extragonadal expression of FSHR and the differential signal pathways activated in these tissues, and lastly, highlight the open questions surrounding the role these gonadotropin hormone receptor complexes and how this will shape future research directions.

Structure-Function Relationships of the Follicle-Stimulating Hormone Receptor.

The follicle-stimulating hormone receptor (FSHR) plays a crucial role in reproduction. This structurally complex receptor is a member of the G-protein coupled receptor (GPCR) superfamily of membrane receptors. As with the other structurally similar glycoprotein hormone receptors (the thyroid-stimulating hormone and luteinizing hormone-chorionic gonadotropin hormone receptors), the FSHR is characterized by an extensive extracellular domain, where binding to FSH occurs, linked to the signal specificity subdomain or hinge region. This region is involved in ligand-stimulated receptor activation whereas the seven transmembrane domain is associated with receptor activation and transmission of the activation process to the intracellular loops comprised of amino acid sequences, which predicate coupling to effectors, interaction with adapter proteins, and triggering of downstream intracellular signaling. In this review, we describe the most important structural features of the FSHR intimately involved in regulation of FSHR function, including trafficking, dimerization, and oligomerization, ligand binding, agonist-stimulated activation, and signal transduction.

Intracellular Follicle-Stimulating Hormone Receptor Trafficking and Signaling.

Models of G protein-coupled receptor (GPCR) signaling have dramatically altered over the past two decades. Indeed, GPCRs such as the follicle-stimulating hormone receptor (FSHR) have contributed to these new emerging models. We now understand that receptor signaling is highly organized at a spatial level, whereby signaling not only occurs from the plasma membrane but distinct intracellular compartments. Recent studies in the role of membrane trafficking and spatial organization of GPCR signaling in regulating gonadotropin hormone receptor activity has identified novel intracellular compartments, which are tightly linked with receptor signaling and reciprocally regulated by the cellular trafficking machinery. Understanding the impact of these cell biological mechanisms to physiology and pathophysiology is emerging for certain GPCRs. However, for FSHR, the potential impact in both health and disease and the therapeutic possibilities of these newly identified systems is currently unknown, but offers the potential to reassess prior strategies, or unveil novel opportunities, in targeting this receptor.

Molecular and functional insights into gonadotropin hormone receptor dimerization and oligomerization

The gonadotropin hormones, follicle stimulating hormone and luteinizing hormone, are essential for reproduction. They work in concert to control multiple aspects of gonadal function to ultimately produce meiotically competent and fertilizable gametes, provide the optimal endometrial environment and support for implantation and maintain pregnancy via progesterone production throughout the first trimester of pregnancy. These complex and multidimensional functions are mediated via the gonadotropin hormone receptors, luteinizing hormone receptor and follicle stimulating hormone receptor, Class A G protein-coupled receptors (GPCR), which couple to multiple G protein-dependent and independent signal pathways to control these physiological processes. Over the last two decades, a plethora of experimental evidence has shown that GPCRs can associate to form dimers and oligomers. This association provides a means of mediating the diverse functional requirements of a single receptor subtype and for the gonadotropin hormone receptors, has been shown to alter the pharmacology and signal activation profile of these receptors. This review will detail the historical and current evidence detailing the formation of gonadotropin hormone receptor homomers and heteromers. We will discuss the functional insights gained from in vitro and in vivo studies, and the potential impact in modulating reproductive health and disease.

Expression of gonadotropin and sex steroid hormone receptor mRNA in the utero-vaginal junction containing sperm storage tubules of oviduct during sexual maturation in Japanese quail

Sex steroid hormones play an important role in reproductive tissue development of avian species. However, their role in Japanese quail is yet to be established. To understand the physiological role of hormones involved in the development of sperm storage tubules (SSTs) in quail, we investigated expression profiles of gonadotropin (LH-R and FSH-R) and sex steroid hormone (PR-R, ER-α and ER-β) receptors in the uterovaginal junction (UVJ) containing SSTs before and during sexual maturation i.e. four to eight weeks. Every week four birds were sacrificed to collect blood and UVJ for sex steroid hormone (progesterone and estrogen) estimation and gene expression profiling of sex steroid hormone (PR-R, ER-α and ER-β) and gonadotropin receptors (LH-R and FSH-R) using qRT-PCR. Receptor expression results showed that the expression of sex steroid receptor (PR-R, ER-α and ER-β) genes were upregulated significantly (P < .05) in SSTs with the advancement of age. The expression of gonadotropin receptors (LH-R and FSH-R) was only high at week 5 and 6 respectively. Serum hormone analysis indicated a significant (P < .05) rise in estradiol till 7th week and progesterone from 7th week onwards. These results suggest that the gonadotropin and sex steroid hormone receptors may have the role in the development and maintenance of UVJ that contains predominantly SSTs during sexual maturation.

Intracellular Trafficking of Gonadotropin Receptors in Health and Disease.

Gonadotropin receptors belong to the highly conserved subfamily of the G protein-coupled receptor (GPCR) superfamily, the so-called Rhodopsin-like family (class A), which is the largest class of GPCRs and currently a major drug target. Both the follicle-stimulating hormone receptor (FSHR) and the luteinizing hormone/chorionic gonadotropin hormone receptor (LHCGR) are mainly located in the gonads where they play key functions associated to essential reproductive functions. As any other protein, gonadotropin receptors must be properly folded into a mature tertiary conformation compatible with quaternary assembly and endoplasmic reticulum export to the cell surface plasma membrane. Several primary and secondary structural features, including presence of particular amino acid residues and short motifs and in addition, posttranslational modifications, regulate intracellular trafficking of gonadotropin receptors to the plasma membrane as well as internalization and recycling of the receptor back to the cell surface after activation by agonist. Inactivating mutations of gonadotropin receptors may derive from receptor misfolding and lead to absent or reduced plasma membrane expression of the altered receptor, thereby manifesting an array of phenotypical abnormalities mostly characterized by reproductive failure and/or abnormal or absence of development of secondary sex characteristics. In this chapter we review the structural requirements necessary for intracellular trafficking of the gonadotropin receptors, and describe how mutations in these receptors may lead to receptor misfolding and disease in humans.

Exploring 3D structure of human gonadotropin hormone receptor at antagonist state using homology modeling, molecular dynamic simulation, and cross-docking studies.

Human gonadotropin hormone receptor, a G-protein coupled receptor, is the target of many medications used in fertility disorders. Obtaining more structural information about the receptor could be useful in many studies related to drug design. In this study, the structure of human gonadotropin receptor was subjected to homology modeling studies and molecular dynamic simulation within a DPPC lipid bilayer for 100ns. Several frames were thereafter extracted from simulation trajectories representing the receptor at different states. In order to find a proper model of the receptor at the antagonist state, all frames were subjected to cross-docking studies of some antagonists with known experimental values (Ki). Frame 194 revealed a reasonable correlation between docking calculated energy scores and experimental activity values (|r| = 0.91). The obtained correlation was validated by means of SSLR and showed the presence of no chance correlation for the obtained model. Different structural features reported for the receptor, such as two disulfide bridges and ionic lock between GLU90 and LYS 121 were also investigated in the final model.

Insight into the molecular mechanisms underlying enhanced gonadotropin hormone receptor activity in polycystic ovarian syndrome

Insight into the molecular mechanisms underlying enhanced gonadotropin hormone receptor activity in polycystic ovarian syndrome

Profiling of FSHR negative allosteric modulators on LH/CGR reveals biased antagonism with implications in steroidogenesis

Biased signaling has recently emerged as an interesting means to modulate the function of many G protein-coupled receptors (GPCRs). Previous studies reported two negative allosteric modulators (NAMs) of follicle-stimulating hormone receptor (FSHR), ADX68692 and ADX68693, with differential effects on FSHR-mediated steroidogenesis and ovulation. In this study, we attempted to pharmacologically profile these NAMs on the closely related luteinizing hormone/chorionic gonadotropin hormone receptor (LH/CGR) with regards to its canonical Gs/cAMP pathway as well as to β-arrestin recruitment in HEK293 cells. The NAMs' effects on cAMP, progesterone and testosterone production were also assessed in murine Leydig tumor cell line (mLTC-1) as well as rat primary Leydig cells. We found that both NAMs strongly antagonized LH/CGR signaling in the different cell models used with ADX68693 being more potent than ADX68692 to inhibit hCG-induced cAMP production in HEK293, mLTC-1 and rat primary Leydig cells as well as β-arrestin 2 recruitment in HEK293 cells. Interestingly, differential antagonism of the two NAMs on hCG-promoted steroidogenesis in mLTC-1 and rat primary Leydig cells was observed. Indeed, a significant inhibition of testosterone production by the two NAMs was observed in both cell types, whereas progesterone production was only inhibited by ADX68693 in rat primary Leydig cells. In addition, while ADX68693 totally abolished testosterone production, ADX68692 had only a partial effect in both mLTC-1 and rat primary Leydig cells. These observations suggest biased effects of the two NAMs on LH/CGR-dependent pathways controlling steroidogenesis. Interestingly, the pharmacological profiles of the two NAMs with respect to steroidogenesis were found to differ from that previously shown on FSHR. This illustrates the complexity of signaling pathways controlling FSHR- and LH/CGR-mediated steroidogenesis, suggesting differential implication of cAMP and β-arrestins mediated by FSHR and LH/CGR. Together, our data demonstrate that ADX68692 and ADX68693 are biased NAMs at the LH/CGR in addition to the FSHR. These pharmacological characteristics are important to consider for potential contraceptive and therapeutic applications based on such compounds.