Serum half-life of pituitary gonadotropins is decreased by sulfonation and increased by sialylation in women

Development and characterization of a novel variant of long-acting bovine follicle-stimulating hormone (brscFSH)

Assisted reproduction is a key aspect of modern animal breeding, providing valuable assistance in improving breeding programs. In this field, the administration of exogenous hormones, such as follicle-stimulating hormone (FSH), plays a crucial role in the induction of multiple ovulations. However, commercial FSH used in veterinary practice has been derived primarily from pituitary glands, obtained mostly from pigs for nearly four decades. Although these hormones have contributed significantly to the advancement of assisted reproductive techniques, they have certain limitations that warrant further improvements. These limitations include contamination with luteinizing hormone (LH), the potential risk of pathogen contamination, the potential to trigger an immune response in non-pig species, and the short half-life in circulation, requiring the implementation of complex 8-dose superovulation schedules. Our research team has developed and characterized a new variant of bovine follicle-stimulating hormone (bscrFSH) to address these limitations. The new hormone is produced recombinantly in CHO cell cultures, with a specific productivity of about 30 pg/cell/day. The bscrFSH can be purified to a high purity of 97 % using a single step of immobilized metal affinity chromatography (IMAC). N-glycan analysis of bscrFSH showed that approximately 74 % of the glycans corresponded to charged structures, including mono-, di-, tri-, and tetra-sialylated glycans. Superovulation trials conducted in cattle revealed that bscrFSH, administered at a total dose of about 0.5 μg per kg of body weight, using a decrescent schedule of 4 doses with 24-h intervals, resulted in an average yield of 8-12 transferable embryos per animal. Further research is required; however, the preliminary findings indicate that bscrFSH, currently packaged under the provisional brand name of Cebitropin B, holds potential as a commercial product for assisted reproduction in ruminants.

Perioperative growth hormone levels as an early predictor of new-onset secondary adrenal insufficiency following transsphenoidal pituitary tumor resection

OBJECTIVE

This study aims to predict new-onset secondary adrenal insufficiency (NOSAI) after transsphenoidal pituitary tumor resection surgery using perioperative growth hormone (GH) and prolactin (PRL) levels, among other factors.

METHODS

A cohort of 124 adult patients who underwent transsphenoidal resection for non-functioning pituitary adenoma, with routine perioperative glucocorticoid use, was used to develop the predictive regression model. An additional 46 patients served as the validation cohort. Generalized additive models were used to identify optimal cut-off points for the variables.

RESULTS

The GH level on postoperative day one (POD1) can be a simple predictor by implementing a cut-off point of 0.41 ng/ml. A value ≤ 0.41 ng/mL predicted NOSAI with 0.6316 sensitivity and 0.7810 specificity for the original cohort and 1.0000 sensitivity and 0.7143 specificity for the validation cohort. The multiple logistic regression model included perioperative PRL level difference, perioperative GH level difference, intraoperative cerebrospinal fluid (CSF) leakage, tumor size, and the combined effect of diabetes insipidus (DI) and relative perioperative GH level difference. The areas under the receiver operating characteristic curves were 0.9410 (original cohort) and 0.9494 (validation cohort) for the regression model.

CONCLUSION

Early morning GH level on POD1 can predict NOSAI with fair accuracy when perioperative stress dose glucocorticoid is administered. Prediction accuracy can be improved by considering CSF leakage, DI, and perioperative changes in GH and PRL in the final regression model.

Prevalence and characteristics of polycystic ovarian syndrome in patients with bipolar disorder

BACKGROUND

Bipolar disorder (BD) is frequently accompanied by endocrine disturbances. We compared the prevalence of polycystic ovary syndrome (PCOS) and related reproductive disorders between drug-naïve BD patients and matched healthy controls (HCs) and between drug-naïve BD patients and BD patients with long-term medication, as well as the clinical metabolic correlates among BD patients.

METHODS

72 drug-naïve BD patients, 98 HCs, and 72 BD patients with long-term medication were recruited in the study. Menstruation was recorded, reproductive hormone levels and metabolic indicators were measured, and a pelvic ultrasound examination was performed via transvaginal sensor for each participant. PCOS was defined using the Rotterdam criteria.

RESULTS

After controlling for demographic variables, drug-naïve BD patients presented higher rates of PCOS than the HCs (OR: 3.02, 95 % CI: 1.09-8.36). Regression analysis showed that long-term treatment with valproate (OR: 3.89, 95 % CI: 1.13-13.37), age (OR: 0.37, 95 % CI: 0.14-0.95), and insulin resistance index (OR: 1.73, 95 % CI: 1.10-12.71) were correlated with PCOS in BD patients.

CONCLUSIONS

Drug-naïve BD patients are susceptible to developing PCOS, and valproate is correlated with increased occurrence and development of PCOS. Therefore, PCOS in BD patients, especially those who use valproate, needs to be investigated and monitored closely by medical personnel.

A semi-automated hybrid HPLC-MS approach for in-depth characterization of intact non-covalent heterodimer glycoforms of gonadotropin biopharmaceuticals

BACKGROUND

Gonadotropins are a class of heavily glycosylated protein hormones, thus extremely challenging to characterize by mass spectrometry. As biopharmaceuticals, gonadotropins are prescribed for the treatment of infertility and are derived from different sources: either from pooled urine of pregnant women or upon production in genetically modified Chinese Hamster Ovary cells. Human chorionic gonadotropin (hCG) is sold as a biopharmaceutical under the name Pregnyl® (urinary hCG, u-hCG) and Ovitrelle® (recombinant hCG, r-hCG), and recombinant human follicle stimulating hormone (r-hFSH) is marketed as Gonal-f®. Recently, we reported the exhaustive characterization of r-hCG at different structural levels.

RESULTS

We implement size exclusion (SE) HPLC-MS to automatize the acquisition of native mass spectra of r-hCG dimer, but also u-hCG and r-hFSH, comparing the drug products up to intact heterodimer level. A hybrid HPLC-MS approach was employed for the characterization of r-hCG, u-hCG and r-hFSH drug products at different structural levels. Released glycans were analyzed by porous graphitized carbon (PGC)-HPLC-MS/MS, glycopeptides by reversed-phase (RP)-HPLC-MS/MS, subunits by RP-HPLC-MS and finally the intact native heterodimers by semi-automated online buffer exchange SE-HPLC-MS. The data were integrated using bioinformatic tools, to finally unravel the composition of 1481 co-existing dimeric glycoforms for r-hCG, 1167 glycoforms for u-hCG, and 1440 glycoforms for r-hFSH, and to compare critical quality attributes of the different drug products such as their degree of sialylation and O-glycosylation.

SIGNIFICANCE AND NOVELTY

The strong alliance of bioanalytics and bioinformatics data integration at the different structural levels allowed the identification of more than thousand different glycoforms of r-hCG, u-hCG, and r-hFSH. The results showed that these biopharmaceuticals differ considerably in their glycosylation patterns and highlight the importance of in-depth characterization of biopharmaceuticals for quality control. © 2017 Elsevier Inc. All rights reserved.

Characterization of beta subunit variants of recombinant human chorionic gonadotrophin

Human chorionic gonadotropin (hCG), an endogenous glycoprotein hormone, has been widely used for the treatment of infertility and corpus luteum defect in women. The biological specificity of hCG is essentially determined by its beta (β-) subunit, whereas the alpha (α-) subunit is a common subunit shared among the gonadotropin family. In development of a therapeutic recombinant hCG, the purity analysis showed that the beta (β-) subunit has two variants, β1 and β2. Structural characterization using a combination of analytical techniques has demonstrated that β1-subunit is derived from non-glycosylation at Asn 13, whereas β2-subunit is a normal species with complete N-glycosylation at both Asn 13 and Asn 30. In vivo Bioactivity evaluation of the r-hCG fractions with various ratios of β1-and β2-subunits showed that incomplete glycosylation at Asn 13 potentially reduced the biological activity of r-hCG to promote uterus growth. Although hCG has a long history of medicinal use, this is the first report to identify the structural difference of hCG β-subunit variants, as well as to preliminary establish the structure-activity relationship of this variation. The obtained results also suggest the importance of variant characterization and necessary quality control of product variants during the development of recombinant protein therapeutics.

Direct Detection of Glycated Human Serum Albumin and Hyperglycosylated IgG3 in Serum, by MALDI-ToF Mass Spectrometry, as a Predictor of COVID-19 Severity

The prefusion spike protein of SARS-CoV-2 binds advanced glycation end product (AGE)-glycated human serum albumin (HSA) and a higher mass (hyperglycosylated/glycated) immunoglobulin (Ig) G3, as determined by matrix assisted laser desorption mass spectrometry (MALDI-ToF). We set out to investigate if the total blood plasma of patients who had recovered from acute respiratory distress syndrome (ARDS) as a result of COVID-19, contained more glycated HSA and higher mass (glycosylated/glycated) IgG3 than those with only clinically mild or asymptomatic infections. A direct serum dilution, and disulphide bond reduction, method was developed and applied to plasma samples from SARS-CoV-2 seronegative (n = 30) and seropositive (n = 31) healthcare workers (HCWs) and 38 convalescent plasma samples from patients who had been admitted with acute respiratory distress (ARDS) associated with COVID-19. Patients recovering from COVID-19 ARDS had significantly higher mass AGE-glycated HSA and higher mass IgG3 levels. This would indicate that increased levels and/or ratios of hyper-glycosylation (probably terminal sialic acid) IgG3 and AGE glycated HSA may be predisposition markers for the development of COVID-19 ARDS as a result of SARS-CoV2 infection. Furthermore, rapid direct analysis of serum/plasma samples by MALDI-ToF for such humoral immune correlates of COVID-19 presents a feasible screening technology for the most at risk; regardless of age or known health conditions.

Determination of Half-lives of Circulating FSH and LH Glycoforms in Women During GnRH Receptor Blockade

CONTEXT

Both FSH and LH circulate as 2 glycoforms, differing in number of glycans: low-N-glycosylated glycoforms, FSHtri and LHdi, and fully N-glycosylated glycoforms, FSHtetra and LHtri.

OBJECTIVES

To determine the half-lives of endogenous circulating gonadotropin glycoforms in women during GnRH receptor blockade.

DESIGN/PARTICIPANTS

Serum samples were collected in 8 healthy women before and up to 20 hours after administration of the NAL-GLU GnRH antagonist. Three women were in early follicular phase, 2 at mid-cycle phase, and 3 were postmenopausal.

MAIN OUTCOME MEASURES

The half-life of each glycoform was estimated by monoexponential decay for FSH (n = 8) and LH (n = 5). Data were analyzed using paired t tests.

RESULTS

Half-lives in the circulation of low-N-glycosylated glycoforms of both FSH and LH were shorter than those of the fully N-glycosylated glycoforms (mean; range, FSHtri 343; 116-686 minutes vs FSHtetra 757; 436-1038, minutes, P = 0.0003; LHdi 125, 84-198 minutes vs LHtri 164, 107-235 minutes, P = 0.004). The half-lives of low-and fully N-glycosylated forms of LH were shorter than the corresponding half-lives of FSH glycoforms, P = 0.0008.

CONCLUSIONS

For both FSH and LH, low-N-glycosylated glycoforms disappeared from the circulation faster than the fully N-glycosylated. The half-lives of low and fully N-glycosylated forms of LH were shorter than the corresponding half-lives of FSH. The estimated values for half-life in the circulation of total FSH and total LH will depend on the relative amounts of the 2 glycoforms of each hormone and their individual disappearance rates in circulation.

Purification Process of a Recombinant Human Follicle Stimulating Hormone Biosimilar (Primapur®) to Yield a Pharmaceutical Product with High Batch-to-Batch Consistency

Recombinant human follicle stimulating hormone (r-hFSH) is widely used for infertility treatment and is subject to the development of biosimilars. There are different purification strategies that can yield r-hFSH of pharmaceutical quality from Chinese hamster ovary cell culture broth. We developed a purification process for r-hFSH centered on immunoaffinity chromatography with single-domain recombinant camelid antibodies. The resulting downstream process is simple and devoid of ultrafiltration operations. Studies on chromatography resin resource and ligand leakage showed that the immunoaffinity matrix employed was suitable for industrial use and stable for at least 40 full chromatography cycles, and the leaked single-domain antibody ligand was completely removed by subsequent purification steps. All chromatography resins employed withstood the same 40 cycles of use without significant changes in separation efficiency and product binding capacity. The resulting industrial purification process yielded batches of r-hFSH with consistent levels of purity and bioactivity.

Reduced FSH and LH action: implications for medically assisted reproduction

Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) play complementary roles in follicle development and ovulation via a complex interaction in the hypothalamus, anterior pituitary gland, reproductive organs, and oocytes. Impairment of the production or action of gonadotropins causes relative or absolute LH and FSH deficiency that compromises gametogenesis and gonadal steroid production, thereby reducing fertility. In women, LH and FSH deficiency is a spectrum of conditions with different functional or organic causes that are characterized by low or normal gonadotropin levels and low oestradiol levels. While the causes and effects of reduced LH and FSH production are very well known, the notion of reduced action has received less attention by researchers. Recent evidence shows that molecular characteristics, signalling as well as ageing, and some polymorphisms negatively affect gonadotropin action. These findings have important clinical implications, in particular for medically assisted reproduction in which diminished action determined by the afore-mentioned factors, combined with reduced endogenous gonadotropin production caused by GnRH analogue protocols, may lead to resistance to gonadotropins and, thus, to an unexpected hypo-response to ovarian stimulation. Indeed, the importance of LH and FSH action has been highlighted by the International Committee for Monitoring Assisted Reproduction Technologies (ICMART) in their definition of hypogonadotropic hypogonadism as gonadal failure associated with reduced gametogenesis and gonadal steroid production due to reduced gonadotropin production or action. The aim of this review is to provide an overview of determinants of reduced FSH and LH action that are associated with a reduced response to ovarian stimulation.

Low- and Fully N-Glycosylated Gonadotropins Circulating in Women With Polycystic Ovary Syndrome

Context

A preponderance of basic luteinizing hormone (LH) molecules having elevated bioactivity was detected in the circulation of women with polycystic ovary syndrome (PCOS). Subsequent studies have shown that LH and follicle-stimulating hormone (FSH) both circulate as glycoforms differing in number of glycans: low-N-glycosylated glycoforms, LHdi and FSHtri, with high in vitro bioactivity, and fully glycosylated glycoforms, LHtri and FSHtetra, with high in vivo bioactivity.

Objective

This work aims to characterize the glycosylation patterns on circulating gonadotropin glycoforms in women with PCOS.

Methods

Serum samples, collected from 8 women with PCOS were included. The concentration, sulfonation, and sialylation of each glycoform were determined and compared with values of serum samples from healthy women: 22 women at follicular phase, 16 at midcycle, and 15 after menopause.

Results

All the women with PCOS had higher LHdi serum levels compared with those in the follicular-phase group. Median LHdi and median LHtri levels were significantly elevated in PCOS women. The percentage of LHdi was increased from 37 to 49 and that of FSHtri was decreased from 41 to 33. The LHdi, LHtri, and FSHtetra glycoforms were more sialylated and both LH glycoforms less sulfonated in women with PCOS.

Conclusion

All women with PCOS had increased serum levels of LHdi, compared with those in the follicular phase. The percentage of LHdi was increased and that of FSHtri decreased in women with PCOS. The increased LHdi leads to maintenance of the abnormal early follicular development of the polycystic ovary, and the decreased FSHtri contributes to the arrested follicle growth.

Identification of Key Receptor Residues Discriminating Human Chorionic Gonadotropin (hCG)- and Luteinizing Hormone (LH)-Specific Signaling

(1) The human luteinizing hormone (LH)/chorionic gonadotropin (hCG) receptor (LHCGR) discriminates its two hormone ligands and differs from the murine receptor (Lhr) in amino acid residues potentially involved in qualitative discerning of LH and hCG. The latter gonadotropin is absent in rodents. The aim of the study is to identify LHCGR residues involved in hCG/LH discrimination. (2) Eight LHCGR cDNAs were developed, carrying “murinizing” mutations on aminoacidic residues assumed to interact specifically with LH, hCG, or both. HEK293 cells expressing a mutant or the wild type receptor were treated with LH or hCG and the kinetics of cyclic adenosine monophosphate (cAMP) and phosphorylated extracellular signal-regulated kinases 1/2 (pERK1/2) activation was analyzed by bioluminescence resonance energy transfer (BRET). (3) Mutations falling within the receptor leucine reach repeat 9 and 10 (LRR9 and LRR10; K225S +T226I and R247T), of the large extracellular binding domain, are linked to loss of hormone-specific induced cAMP increase, as well as hCG-specific pERK1/2 activation, leading to a Lhr-like modulation of the LHCGR-mediated intracellular signaling pattern. These results support the hypothesis that LHCGR LRR domain is the interaction site of the hormone β-L2 loop, which differs between LH and hCG, and might be fundamental for inducing gonadotropin-specific signals. (4) Taken together, these data identify LHCGR key residues likely evolved in the human to discriminate LH/hCG specific binding.

Gonadotropin Glycoforms Circulating in Women Using Progestins of the Levonorgestrel Family for Contraception

Context

The progestins of the levonorgestrel family are 13-ethylgonane progestins, commonly used for contraception in women. One contraceptive effect of these progestins is inhibition of ovulation, which may be a result of changes in gonadotropin glycosylation patterns. Gonadotropin glycoforms differ in number of glycans and bioactivity: more bioactive low-N-glycosylated glycoforms, diglycosylated luteinizing hormone (LHdi) and triglycosylated follicle-stimulating hormone (FSHtri), and less bioactive fully N-glycosylated glycoforms, LHtri and FSHtetra.

Objective

Characterize the glycosylation patterns on the circulating gonadotropin glycoforms in women using 13-ethylgonane progestins for contraception.

Design, Subjects, Main Outcome Measures

Serum samples, collected from 92 healthy women using 13-ethylgonane progestins for contraception, were included. Forty women used progestin-only continuously and 52 used progestins combined with ethinylestradiol (EE) for 3 weeks followed by a hormone-free week. Concentration, sulfonation, and sialylation of each glycoform were determined and compared with follicular phase values of normal menstrual cycles.

Results

The progestin-only group had significantly increased serum levels, decreased sulfonation, and increased sialylation of LHdi. The LHdi/FSHtri ratio was increased. The progestin+EE group had significantly decreased gonadotropin glycoform concentrations and decreased sialylation of FSHtri. The progestin+EE effect on sialylation of FSHtri occurred later during the treatment cycle in contrast to the effect on FSHtri concentration.

Conclusions

The 2 different progestin treatments induced different effects on the glycan synthesis and concentrations of more bioactive low-glycosylated gonadotropins. Progestin-only treatment increased sialylation and decreased sulfonation of LHdi molecules, contributing to sustained higher levels of bioactive LHdi molecules. Progestin+EE treatment decreased sialylation of FSHtri, contributing to a shorter half-life and decreased levels of bioactive FSHtri.

Unique Pattern of N-Glycosylation, Sialylation, and Sulfonation on TSH Molecules in Serum of Children Up to 18 Months

CONTEXT

N-glycosylation and glycan composition of human TSH molecules modulate the biological properties of TSH in different physiological and clinical situations. The degree of sialylation of serum TSH was reported to be very low in normal third-trimester fetuses compared with normal adults. The circulating TSH glycoforms and their glycan compositions in young children have hitherto not been determined.

OBJECTIVE

To characterize N-glycosylation and glycan composition of circulating TSH molecules in young children.

DESIGN, PARTICIPANTS, MAIN OUTCOME MEASURES

Serum samples were obtained from euthyroid individuals: 33 children, age 2 weeks to 3 years, and 264 adults. The di-glycosylated TSH and tri-glycosylated TSH glycoforms were determined and characterized with respect to sialylation and sulfonation. The TSH N-glycosylation was also examined in pituitary extracts of 75 individuals.

RESULTS

In children up to 18 months of age, most TSH molecules were low-N-glycosylated, high-sulfonated, and low-sialylated compared with older children and adults. The degree of N-glycosylation was similar in serum and pituitary extracts up to 3 months of age and after that was higher in serum than in pituitary extracts.

CONCLUSIONS

Children up to age 18 months had low-sialylated TSH molecules, similar to those reported for third-trimester fetuses. Most TSH molecules in young children were of smaller size and less negatively charged, favoring transport into their target tissues. The low sialylation favors a high biopotency at thyroid and extrathyroidal TSH receptors. A delayed development of the liver SO3-N-acetylgalactosamine receptor function after birth is a likely explanation of the highly sulfonated TSH molecules in serum samples of infants.

Recombinant luteinizing hormone supplementation in assisted reproductive technology: a systematic review

OBJECTIVE

To assess the role of recombinant human LH (r-hLH) supplementation in ovarian stimulation for ART in specific subgroups of patients.

DESIGN

Systematic review.

SETTING

Centers for reproductive care.

PATIENT(S)

Six populations were investigated: 1) women with a hyporesponse to recombinant human FSH (r-hFSH) monotherapy; 2) women at an advanced reproductive age; 3) women cotreated with the use of a GnRH antagonist; 4) women with profoundly suppressed LH levels after the administration of GnRH agonists; 5) normoresponder women to prevent ovarian hyperstimulation syndrome; and 6) women with a "poor response" to ovarian stimulation, including those who met the European Society for Human Reproduction and Embryology Bologna criteria.

INTERVENTION(S)

Systematic review.

MAIN OUTCOME MEASURE(S)

Implantation rate, number of oocytes retrieved, live birth rate, ongoing pregnancy rate, fertilization rate, and number of metaphase II oocytes.

RESULT(S)

Recombinant hLH supplementation appears to be beneficial in two subgroups of patients: 1) women with adequate prestimulation ovarian reserve parameters and an unexpected hyporesponse to r-hFSH monotherapy; and 2) women 36-39 years of age. Indeed, there is no evidence that r-hLH is beneficial in young (<35 y) normoresponders cotreated with the use of a GnRH antagonist. The use of r-hLH supplementation in women with suppressed endogenous LH levels caused by GnRH analogues and in poor responders remains controversial, whereas the use of r-hLH supplementation to prevent the development of ovarian hyperstimulation syndrome warrants further investigation.

CONCLUSION(S)

Recombinant hLH can be proposed for hyporesponders and women 36-39 years of age.

Gonadotropins and Their Analogs: Current and Potential Clinical Applications

The gonadotropin receptors LH receptor and FSH receptor play a central role in governing reproductive competency/fertility. Gonadotropin hormone analogs have been used clinically for decades in assisted reproductive therapies and in the treatment of various infertility disorders. Though these treatments are effective, the clinical protocols demand multiple injections, and the hormone preparations can lack uniformity and stability. The past two decades have seen a drive to develop chimeric and modified peptide analogs with more desirable pharmacokinetic profiles, with some displaying clinical efficacy, such as corifollitropin alfa, which is now in clinical use. More recently, low-molecular-weight, orally active molecules with activity at gonadotropin receptors have been developed. Some have excellent characteristics in animals and in human studies but have not reached the market-largely as a result of acquisitions by large pharma. Nonetheless, such molecules have the potential to mitigate risks currently associated with gonadotropin-based fertility treatments, such as ovarian hyperstimulation syndrome and the demands of injection-based therapies. There is also scope for novel use beyond the current remit of gonadotropin analogs in fertility treatments, including application as novel contraceptives; in the treatment of polycystic ovary syndrome; in the restoration of function to inactivating mutations of gonadotropin receptors; in the treatment of ovarian and prostate cancers; and in the prevention of bone loss and weight gain in postmenopausal women. Here we review the properties and clinical application of current gonadotropin preparations and their analogs, as well as the development of novel orally active, small-molecule nonpeptide analogs.

Betaglycan (TGFBR3) Functions as an Inhibin A, but Not Inhibin B, Coreceptor in Pituitary Gonadotrope Cells in Mice

Inhibins are gonadal hormones that act on pituitary gonadotrope cells to suppress FSH synthesis and secretion. Inhibin A and B are heterodimers of the inhibin ⍺-subunit disulfide-linked to one of two inhibin β-subunits. Homodimers or heterodimers of the inhibin β-subunits form the activins, which stimulate FSH production. Activins signal through complexes of type I and II receptor serine/threonine kinases to increase transcription of the FSHβ subunit gene. According to in vitro observations, inhibins impair FSH synthesis by competitively binding to activin type II receptors, particularly in the presence of the TGFβ type III receptor (TGFBR3, or betaglycan). The role of TGFBR3 in inhibin action in vivo has not been determined. Here, we ablated Tgfbr3 specifically in murine gonadotropes. Conditional knockout females were supra-fertile, exhibiting enhanced folliculogenesis, numbers of ovulated eggs per cycle, and litter sizes relative to control mice. Despite these phenotypes, FSH levels appeared to be unaltered in knockout mice, and the mechanisms underlying their enhanced fertility remain unexplained. Inhibin B is the predominant form of the hormone in males and in females during most stages of the estrous cycle. Remarkably, inhibin A, but not inhibin B, suppression of FSH synthesis was impaired in cultured pituitaries of knockout mice, which may explain the absence of discernible changes in FSH levels in vivo. Collectively, these data challenge current dogma by demonstrating that TGFBR3 (betaglycan) functions as an inhibin A, but not an inhibin B, coreceptor in gonadotrope cells in vivo. Mechanisms of inhibin B action merit further investigation.

Two Hormones for One Receptor: Evolution, Biochemistry, Actions, and Pathophysiology of LH and hCG

LH and chorionic gonadotropin (CG) are glycoproteins fundamental to sexual development and reproduction. Because they act on the same receptor (LHCGR), the general consensus has been that LH and human CG (hCG) are equivalent. However, separate evolution of LHβ and hCGβ subunits occurred in primates, resulting in two molecules sharing ~85% identity and regulating different physiological events. Pituitary, pulsatile LH production results in an ~90-minute half-life molecule targeting the gonads to regulate gametogenesis and androgen synthesis. Trophoblast hCG, the "pregnancy hormone," exists in several isoforms and glycosylation variants with long half-lives (hours) and angiogenic potential and acts on luteinized ovarian cells as progestational. The different molecular features of LH and hCG lead to hormone-specific LHCGR binding and intracellular signaling cascades. In ovarian cells, LH action is preferentially exerted through kinases, phosphorylated extracellular-regulated kinase 1/2 (pERK1/2) and phosphorylated AKT (also known as protein kinase B), resulting in irreplaceable proliferative/antiapoptotic signals and partial agonism on progesterone production in vitro. In contrast, hCG displays notable cAMP/protein kinase A (PKA)-mediated steroidogenic and proapoptotic potential, which is masked by estrogen action in vivo. In vitro data have been confirmed by a large data set from assisted reproduction, because the steroidogenic potential of hCG positively affects the number of retrieved oocytes, and LH affects the pregnancy rate (per oocyte number). Leydig cell in vitro exposure to hCG results in qualitatively similar cAMP/PKA and pERK1/2 activation compared with LH and testosterone. The supposed equivalence of LH and hCG has been disproved by such data, highlighting their sex-specific functions and thus deeming it an oversight caused by incomplete understanding of clinical data.

Low-glycosylated forms of both FSH and LH play major roles in the natural ovarian stimulation

BACKGROUND

The natural ovarian stimulation is mediated by four gonadotrophin glycoforms: FSHtri with three, FSHtetra with four, LHdi with two, and LHtri with three N-glycans. The aim of the study was to determine the serum concentrations of the four glycoforms and their contents of anionic monosaccharides (AMS), i.e. sialic acid (SA) and sulfonated N-acetylgalactosamine (SU) residues throughout the menstrual cycle.

METHODS

Serum samples were collected from 78 healthy women with regular menstrual cycles. The serum glycoform molecules were identified by their distributions at electrophoreses. Analyses were also performed after removal of terminal SA. The hormones were measured with time-resolved sandwich fluoroimmunoassays.

RESULTS

The concentration profiles of the four glycoforms were markedly different. FSHtri, which had a 3-fold higher biopotency than FSHtetra, had peak levels on cycle day 5 and at midcycle and nadirs on cycle days 9 and 21-23. FSHtetra had a raised level on cycle days 5-12, followed by a decrease. LHdi and LHtri had similar patterns, but the peak/nadir ratio was much more pronounced for LHdi than for LHtri, 18 versus 4. The numbers of SA residues per molecule were at a maximum around midcycle when the corresponding numbers of SU were at a minimum. The SU/SA ratio was at a minimum on cycle day 12.

CONCLUSION

The results indicate that the LHdi and the FSHtri molecules play major roles in the natural ovarian stimulation. The SU/SA ratios per molecule favoured a prolonged circulatory half-life of all glycoforms at the midcycle phase. The observations may lead to more successful inductions of ovulation in anovulatory women.

Integration of genetic and metabolic features related to sialic acid metabolism distinguishes human breast cell subtypes

In this report we use 'high-flux' tributanoyl-modified N-acetylmannosamine (ManNAc) analogs with natural N-acetyl as well as non-natural azido- and alkyne N-acyl groups (specifically, 1,3,4-O-Bu3ManNAc, 1,3,4-O-Bu3ManNAz, and 1,3,4-O-Bu3ManNAl respectively) to probe intracellular sialic acid metabolism in the near-normal MCF10A human breast cell line in comparison with earlier stage T-47D and more advanced stage MDA-MB-231 breast cancer lines. An integrated view of sialic acid metabolism was gained by measuring intracellular sialic acid production in tandem with transcriptional profiling of genes linked to sialic acid metabolism. The transcriptional profiling showed several differences between the three lines in the absence of ManNAc analog supplementation that helps explain the different sialoglycan profiles naturally associated with cancer. Only minor changes in mRNA transcript levels occurred upon exposure to the compounds confirming that metabolic flux alone can be a key determinant of sialoglycoconjugate display in breast cancer cells; this result complements the well-established role of genetic control (e.g., the transcription of STs) of sialylation abnormalities ubiquitously associated with cancer. A notable result was that the different cell lines produced significantly different levels of sialic acid upon exogenous ManNAc supplementation, indicating that feedback inhibition of UDP-GlcNAc 2-epimerase/ManNAc kinase (GNE)-generally regarded as the 'gatekeeper' enzyme for titering flux into sialic acid biosynthesis-is not the only regulatory mechanism that limits production of this sugar. A notable aspect of our metabolic glycoengineering approach is its ability to discriminate cell subtype based on intracellular metabolism by illuminating otherwise hidden cell type-specific features. We believe that this strategy combined with multi-dimensional analysis of sialic acid metabolism will ultimately provide novel insights into breast cancer subtypes and provide a foundation for new methods of diagnosis.

Molecular size and charge as dimensions to identify and characterize circulating glycoforms of human FSH, LH and TSH

BACKGROUND

FSH, LH, and TSH are glycoprotein hormones secreted from the pituitary as fully and low-asparagine-glycosylated hormones. These glycoforms of the hormones exist as a large number of isoforms varying in their glycan contents of terminal anionic monosaccharides (AMS), i.e. sialic acid (SA) and sulfonated N-acetylgalactosamine (SU). Due to the immense heterogeneity and the low concentrations in serum it has been a challenge to develop reliable analytical methods to measure and characterize the circulating glycoforms of these hormones.

METHODS

The hormones were separated with respect to AMS content per molecule by calibrated 0.1% agarose suspension electrophoreses. Glycoforms in separated fractions were then analyzed with respect to size by 180 calibrated Sephadex G-100 gel filtrations. The hormones were measured with time-resolved sandwich fluoroimmunoassays. All separations and assays were performed in veronal buffer at pH 8.7. Sera and fractions were also analyzed after removal of terminal SA.

RESULTS

In addition to the fully glycosylated FSH, LH, and TSH, also tri-glycosylated FSH and di-glycosylated LH and TSH forms could be identified in serum samples. The low- and fully glycosylated hormones differed both with respect to size and to median number of AMS per molecule. Algorithms, based on the distributions by electrophoreses, were developed for each hormone to estimate percent low-glycosylated forms in serum. The median numbers of SA and SU per glycoform molecule were estimated using results obtained after desialylation.

CONCLUSION

The methods can be used for identification and characterization of glycoforms of circulating FSH, LH, and TSH in physiological and clinical studies.

Glycosidases in porcine follicular fluid and their effect on zona pellucida-AWN 1 spermadhesin interaction

Oligosaccharide moieties on the surface of the oocyte belong to the key molecules that direct the course of fertilization and are subjected to changes during oocyte maturation in the follicle. In our study, we focused on the activities of five glycosidases in the fluids from porcine secondary and preovulatory follicles (α-l-fucosidase, α-d-galactosidase, β-d-galactosidase, β-D-N-acetylhexosaminidase, and α-d-mannosidase). All of them were detected active at neutral and acidic pH. However, changes in their activities associated with follicle development were observed only in the case of α-d-mannosidase, which was increased (P < 0.001), and β-d-galactosidase, which was decreased (P < 0.001) at neutral pH, and of α-d-galactosidase and β-N-acetylhexosaminidase, which were decreased (P < 0.0001) at the acidic pH. The comparison of glycosidases from follicular fluid and from blood plasma using red native electrophoresis revealed that most of the glycosidases are present in more than one isoenzyme form; some of them were detected mainly in the follicular fluid. Finally, we tested the effect of glycosidases on the interaction between zona pellucida and AWN 1 spermadhesin (putative sperm receptor of zona pellucida) and demonstrated that the effect of both β-d-galactosidase and to a lesser degree α-d-mannosidase led to a decrease in this interaction. We can hypothesize that these two glycosidases modulate the amount of zona pellucida oligosaccharide moieties and/or their structures for an optimal sperm binding in pigs.

Clinical efficacy of recombinant versus highly purified follicle-stimulating hormone according to follicle-stimulating hormone receptor genotype

OBJECTIVE

Conflicting data have been reported on the comparative doses of recombinant follicle-stimulating hormone (rFSH) and urinary highly purified follicle-stimulating hormone (HP-FSH) required for ovarian stimulation. Nothing is known about the clinical efficacy of rFSH or HP-FSH depending on the N680S follicle-stimulating hormone receptor (FSHR) polymorphism. Our aim was to investigate whether the N680S polymorphism of the FSHR gene affects ovarian response with different forms of FSH.

MATERIALS AND METHODS

This retrospective cohort study includes 382 cycles performed at Instituto Bernabeu from 191 oocyte donors. All donors carried out two cycles: one with rFSH and the other one with HP-FSH (group 1, n=63), both with HP-FSH (group 2, n=100) or both with rFSH (group 3, n=28). The results were compared by pairs from each patient. The main outcomes were oocyte yield, metaphase II matured oocytes (MII), days of stimulation, and gonadotropin dosage.

RESULTS

No significant differences were found when we compared the cycles for donors in group 1. However, according to the FSHR polymorphism, statistical differences were shown. For the SS genotype, more oocytes (16.9 vs. 18.4) and MII (12.8 vs. 15.5) were yielded in the HP-FSH cycle. For the NS genotype, more oocyte (20.1 vs. 16.9) and MII (17.4 vs. 14.2) were yielded in the rFSH cycle. For the NN genotype, no differences were found. No differences were found when we compared the cycles in groups 2 and 3 irrespective of the FSHR polymorphism.

CONCLUSION

For the first time, we have shown in a population of egg donors that the N680S FSHR gene polymorphism affects the efficacy of HP-FSH or rFSH. The FSHR genotype is an important factor to determine the dosage and the nature of the gonadotropin selected for ovarian stimulation.

Ubiquitous Importance of Protein Glycosylation

More than half of all proteins are glycosylated. The attached glycans provide proteins with important structural and functional properties and glycan parts of glycoproteins have essential roles in many key biological processes. This chapter describes the effect of glycosylation on the structure and function of proteins, with emphasis on regulation of protein half-life and modulation of protein function by alternative glycosylation. In addition, this chapter highlights the importance of glycan-lectin interactions, the ability of glycans to block phosphorylation of proteins, and the importance of glycans in disease.

The Pathogenesis of Polycystic Ovary Syndrome (PCOS): The Hypothesis of PCOS as Functional Ovarian Hyperandrogenism Revisited

Polycystic ovary syndrome (PCOS) was hypothesized to result from functional ovarian hyperandrogenism (FOH) due to dysregulation of androgen secretion in 1989-1995. Subsequent studies have supported and amplified this hypothesis. When defined as otherwise unexplained hyperandrogenic oligoanovulation, two-thirds of PCOS cases have functionally typical FOH, characterized by 17-hydroxyprogesterone hyperresponsiveness to gonadotropin stimulation. Two-thirds of the remaining PCOS have FOH detectable by testosterone elevation after suppression of adrenal androgen production. About 3% of PCOS have a related isolated functional adrenal hyperandrogenism. The remaining PCOS cases are mild and lack evidence of steroid secretory abnormalities; most of these are obese, which we postulate to account for their atypical PCOS. Approximately half of normal women with polycystic ovarian morphology (PCOM) have subclinical FOH-related steroidogenic defects. Theca cells from polycystic ovaries of classic PCOS patients in long-term culture have an intrinsic steroidogenic dysregulation that can account for the steroidogenic abnormalities typical of FOH. These cells overexpress most steroidogenic enzymes, particularly cytochrome P450c17. Overexpression of a protein identified by genome-wide association screening, differentially expressed in normal and neoplastic development 1A.V2, in normal theca cells has reproduced this PCOS phenotype in vitro. A metabolic syndrome of obesity-related and/or intrinsic insulin resistance occurs in about half of PCOS patients, and the compensatory hyperinsulinism has tissue-selective effects, which include aggravation of hyperandrogenism. PCOS seems to arise as a complex trait that results from the interaction of diverse genetic and environmental factors. Heritable factors include PCOM, hyperandrogenemia, insulin resistance, and insulin secretory defects. Environmental factors include prenatal androgen exposure and poor fetal growth, whereas acquired obesity is a major postnatal factor. The variety of pathways involved and lack of a common thread attests to the multifactorial nature and heterogeneity of the syndrome. Further research into the fundamental basis of the disorder will be necessary to optimally correct androgen levels, ovulation, and metabolic homeostasis.

Clinical Applications of Gonadotropins in the Male

The pituitary gonadotropins, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) play a pivotal role in reproduction. The synthesis and secretion of gonadotropins are regulated by complex interactions among several endocrine, paracrine, and autocrine factors of diverse chemical structure. In men, LH regulates the synthesis of androgens by the Leydig cells, whereas FSH promotes Sertoli cell function and thereby influences spermatogenesis. Gonadotropins are complex molecules composed of two subunits, the α- and β-subunit, that are noncovalently associated. Gonadotropins are decorated with glycans that regulate several functions of the protein including folding, heterodimerization, stability, transport, conformational maturation, efficiency of heterodimer secretion, metabolic fate, interaction with their cognate receptor, and selective activation of signaling pathways. A number of congenital and acquired abnormalities lead to gonadotropin deficiency and hypogonadotropic hypogonadism, a condition amenable to treatment with exogenous gonadotropins. Several natural and recombinant preparations of gonadotropins are currently available for therapeutic purposes. The difference between natural and the currently available recombinant preparations (which are massively produced in Chinese hamster ovary cells for commercial purposes) mainly lies in the abundance of some of the carbohydrates that conform the complex glycans attached to the protein core. Whereas administration of exogenous gonadotropins in patients with isolated congenital hypogonadotropic hypogonadism is a well recognized therapeutic approach, their role in treating men with normogonadotropic idiopathic infertility is still controversial. This chapter concentrates on the main structural and functional features of the gonadotropin hormones and how basic concepts have been translated into the clinical arena to guide therapy for gonadotropin deficit in males.

Sex-specific regulation of follicle-stimulating hormone secretion by synaptotagmin 9

The anterior pituitary releases six different hormones that control virtually all aspects of vertebrate physiology, yet the molecular mechanisms underlying their Ca(2+)-triggered release remain unknown. A subset of the synaptotagmin (syt) family of proteins serve as Ca(2+) sensors for exocytosis in neurons and neuroendocrine cells, and are thus likely to regulate pituitary hormone secretion. Here we show that numerous syt isoforms are highly expressed in the pituitary gland in a lobe, and sex-specific manner. We further investigated a Ca(2+)-activated isoform, syt-9, and found that it is expressed in a subpopulation of anterior pituitary cells, the gonadotropes. Follicle-stimulating hormone (FSH) and syt-9 are highly co-localized in female, but not male, mice. Loss of syt-9 results in diminished basal and stimulated FSH secretion only in females, resulting in alterations in the oestrus cycle. This work uncovers a new function for syt-9 and reveals a novel sex difference in reproductive hormone secretion.

Endocrinology of the Menopause

In women, age-related changes in ovarian function begin in the mid-30s with decreased fertility and compensatory hormonal changes in the hypothalamus-pituitary-gonadal axis that maintain follicle development and estrogen secretion in the face of a waning pool of ovarian follicles. The menopause transition is characterized by marked variability in follicle development, ovulation, bleeding patterns, and symptoms of hyper- and hypoestrogenism. The menopause, which is clinically defined by the last menstrual period, is followed by the consistent absence of ovarian secretion of estradiol.

Glycoengineering of Chinese hamster ovary cells for enhanced erythropoietin N-glycan branching and sialylation

Sialic acid, a terminal residue on complex N-glycans, and branching or antennarity can play key roles in both the biological activity and circulatory lifetime of recombinant glycoproteins of therapeutic interest. In order to examine the impact of glycosyltransferase expression on the N-glycosylation of recombinant erythropoietin (rEPO), a human α2,6-sialyltransferase (ST6Gal1) was expressed in Chinese hamster ovary (CHO-K1) cells. Sialylation increased on both EPO and CHO cellular proteins as observed by SNA lectin analysis, and HPLC profiling revealed that the sialic acid content of total glycans on EPO increased by 26%. The increase in sialic acid content was further verified by detailed profiling of the N-glycan structures using mass spectra (MS) analysis. In order to enhance antennarity/branching, UDP-N-acetylglucosamine: α-1,3-D-mannoside β1,4-N-acetylglucosaminyltransferase (GnTIV/Mgat4) and UDP-N-acetylglucosamine:α-1,6-D-mannoside β1,6-N-acetylglucosaminyltransferase (GnTV/Mgat5), was incorporated into CHO-K1 together with ST6Gal1. Tri- and tetraantennary N-glycans represented approximately 92% of the total N-glycans on the resulting EPO as measured using MS analysis. Furthermore, sialic acid content of rEPO from these engineered cells was increased ∼45% higher with tetra-sialylation accounting for ∼10% of total sugar chains compared to ∼3% for the wild-type parental CHO-K1. In this way, coordinated overexpression of these three glycosyltransferases for the first time in model CHO-K1 cell lines provides a mean for enhancing both N-glycan branching complexity and sialylation with opportunities to generate tailored complex N-glycan structures on therapeutic glycoproteins in the future.

'Carriers of variant luteinizing hormone (V-LH) among 1593 Baltic men have significantly higher serum LH'

Luteinizing hormone (LH) is a pituitary heterodimeric glycoprotein essential in male and female reproduction. Its functional polymorphic variant (V‐LH) is determined by two missense mutations (rs1800447, A/G, Trp8Arg; rs34349826, A/G, Ile15Thr) in the LH β‐subunit encoding gene (LHB; 19q13.3; 1111 bp; 3 exons). Among women, V‐LH has been associated with higher circulating LH and reduced fertility, but the knowledge of its effect on male reproductive parameters has been inconclusive. The objective of this study was to assess the effect of V‐LH on hormonal, seminal and testicular parameters in the Baltic young men cohort (n = 986; age: 20.1 ± 2.1 years) and Estonian idiopathic infertility patients (n = 607; 35.1 ± 5.9 years). V‐LH was detected by genotyping of the underlying DNA polymorphisms using PCR‐RFLP combined with resequencing of a random subset of subjects. Genetic associations were tested using linear regression under additive model and results were combined in meta‐analysis. No significant difference was detected between young men and infertility patients for the V‐LH allele frequency (11.0 vs. 9.3%, respectively). V‐LH was associated with higher serum LH in both, the young men cohort (p = 0.022, allelic effect = 0.26 IU/L) and the idiopathic infertility group (p = 0.008, effect = 0.59 IU/L). In meta‐analysis, the statistical significance was enhanced (p = 0.0007, resistant to Bonferroni correction for multiple testing; effect = 0.33 IU/L). The detected significant association of V‐LH with increased serum LH remained unchanged after additional adjustment for the SNPs previously demonstrated to affect LH levels (FSHB ‐211G/T, FSHR Asn680Ser, FSHR ‐29A/G). Additionally, a suggestive trend for association with reduced testicular volume was observed among young men, and with lower serum FSH among infertility patients. The V‐LH carrier status did not affect sperm parameters and other circulating reproductive hormones. For the first time, we show a conclusive contribution of V‐LH to the natural variance in male serum LH levels. Its downstream clinical consequences are still to be learned.

Tissue-specific posttranslational modification allows functional targeting of thyrotropin

Thyroid-stimulating hormone (TSH; thyrotropin) is a glycoprotein secreted from the pituitary gland. Pars distalis-derived TSH (PD-TSH) stimulates the thyroid gland to produce thyroid hormones (THs), whereas pars tuberalis-derived TSH (PT-TSH) acts on the hypothalamus to regulate seasonal physiology and behavior. However, it had not been clear how these two TSHs avoid functional crosstalk. Here, we show that this regulation is mediated by tissue-specific glycosylation. Although PT-TSH is released into the circulation, it does not stimulate the thyroid gland. PD-TSH is known to have sulfated biantennary N-glycans, and sulfated TSH is rapidly metabolized in the liver. In contrast, PT-TSH has sialylated multibranched N-glycans; in the circulation, it forms the macro-TSH complex with immunoglobulin or albumin, resulting in the loss of its bioactivity. Glycosylation is fundamental to a wide range of biological processes. This report demonstrates its involvement in preventing functional crosstalk of signaling molecules in the body.

Sequential (hFSH + recFSH) vs homogenous (hFSH or recFSH alone) stimulation: clinical and biochemical (cumulus cell gene expression) aspects

FSH is a key hormone in the regulation of follicular development. Together with the EGF network, these molecules mediate oocyte maturation and competence in preparation for the action of LH. FSH isoforms regulate distinct biological pathways and have specific effects on granulosa cell function and maturation of the ovarian follicle. Their dynamic interactions occur during the follicular cycle; short-living forms are predominant in the pre-ovulatory phase, whereas long-acting molecules characterize the luteal-follicular transition. Recombinant FSH (rFSH) molecules have a reduced number of isoforms and are less acidic, with a shorter half-life. We have investigated sequential stimulation, comparing hFSH + rFSH, vs. rFSH alone and hFSH alone for the entire stimulation phase. Sequential stimulation leads to an E2 per MII oocyte ratio that is much lower than is seen during treatment with the two drugs individually. Although there is a positive tendency in favor of the sequential treatment, there was no significant difference in pregnancy rates, even taking frozen embryos into consideration. The cumulus cell transcriptome varies considerably between the treatments, although with no clear significance. When comparing pregnant vs. non-pregnant patients, in general a decrease in mRNA expression can be observed in the pregnant patients, especially in expression of folic acid receptor 1 and ovostatin 2. This indicates that material has been transferred from CC to the oocyte. However, a common observation in the literature is that variations in the transcriptome of the cumulus cells are highly dependent upon the patient genotype; the potential for applying this strategy as a basis for selecting embryos is, at the very least, questionable.

Luteinizing hormone and human chorionic gonadotropin: origins of difference

Luteinizing hormone (LH) and human chorionic gonadotropin (hCG) are widely recognized for their roles in ovulation and the support of early pregnancy. Aside from the timing of expression, however, the differences between LH and hCG have largely been overlooked in the clinical realm because of their similar molecular structures and shared receptor. With technologic advancements, including the development of highly purified and recombinant gonadotropins, researchers now appreciate that these hormones are not as interchangeable as once believed. Although they bind to a common receptor, emerging evidence suggests that LH and hCG have disparate effects on downstream signaling cascades. Increased understanding of the inherent differences between LH and hCG will foster more effective diagnostic and prognostic assays for use in a variety of clinical contexts and support the individualization of treatment strategies for conditions such as infertility.

The global effect of follicle-stimulating hormone and tumour necrosis factor α on gene expression in cultured bovine ovarian granulosa cells

BACKGROUND

Oocytes mature in ovarian follicles surrounded by granulosa cells. During follicle growth, granulosa cells replicate and secrete hormones, particularly steroids close to ovulation. However, most follicles cease growing and undergo atresia or regression instead of ovulating. To investigate the effects of stimulatory (follicle-stimulating hormone; FSH) and inhibitory (tumour necrosis factor alpha; TNFα) factors on the granulosa cell transcriptome, bovine ovaries were obtained from a local abattoir and pools of granulosa cells were cultured in vitro for six days under defined serum-free conditions with treatments present on days 3-6. Initially dose-response experiments (n = 4) were performed to determine the optimal concentrations of FSH (0.33 ng/ml) and TNFα (10 ng/ml) to be used for the microarray experiments. For array experiments cells were cultured under control conditions, with FSH, with TNFα, or with FSH plus TNFα (n = 4 per group) and RNA was harvested for microarray analyses.

RESULTS

Statistical analysis showed primary clustering of the arrays into two groups, control/FSH and TNFα/TNFα plus FSH. The effect of TNFα on gene expression dominated that of FSH, with substantially more genes differentially regulated, and the pathways and genes regulated by TNFα being similar to those of FSH plus TNFα treatment. TNFα treatment reduced the endocrine activity of granulosa cells with reductions in expression of FST, INHA, INBA and AMH. The top-ranked canonical pathways and GO biological terms for the TNFα treatments included antigen presentation, inflammatory response and other pathways indicative of innate immune function and fibrosis. The two most significant networks also reflect this, containing molecules which are present in the canonical pathways of hepatic fibrosis/hepatic stellate cell activation and transforming growth factor β signalling, and these were up regulated. Upstream regulator analyses also predicted TNF, interferons γ and β1 and interleukin 1β.

CONCLUSIONS

In vitro, the transcriptome of granulosa cells responded minimally to FSH compared with the response to TNFα. The response to TNFα indicated an active process akin to tissue remodelling as would occur upon atresia. Additionally there was reduction in endocrine function and induction of an inflammatory response to TNFα that displays features similar to immune cells.

Gonadotropin therapy in assisted reproduction: an evolutionary perspective from biologics to biotech

Gonadotropin therapy plays an integral role in ovarian stimulation for infertility treatments. Efforts have been made over the last century to improve gonadotropin preparations. Undoubtedly, current gonadotropins have better quality and safety profiles as well as clinical efficacy than earlier ones. A major achievement has been introducing recombinant technology in the manufacturing processes for follicle-stimulating hormone, luteinizing hormone, and human chorionic gonadotropin. Recombinant gonadotropins are purer than urine-derived gonadotropins, and incorporating vial filling by mass virtually eliminated batch-to-batch variations and enabled accurate dosing. Recombinant and fill-by-mass technologies have been the driving forces for launching of prefilled pen devices for more patient-friendly ovarian stimulation. The most recent developments include the fixed combination of follitropin alfa + lutropin alfa, long-acting FSH gonadotropin, and a new family of prefilled pen injector devices for administration of recombinant gonadotropins. The next step would be the production of orally bioactive molecules with selective follicle-stimulating hormone and luteinizing hormone activity.

Dynamic changes in glycosylation and glycan composition of serum FSH and LH during natural ovarian stimulation

BACKGROUND

Glycosylation and glycan composition are of fundamental importance for the biological properties of FSH and LH. The aim of this study was to determine the glycosylation, sialylation, and sulfonation of serum FSH and LH throughout the normal menstrual cycle.

METHODS

Serum samples were collected from 79 healthy women with regular menstrual cycles. The mean numbers of anionic monosaccharide (AMS), sialic acid (SA), and sulfonated N-acetylgalactosamine (SU) residues per FSH and LH molecule were estimated for all sera with methods based on electrophoreses, neuraminidase treatments, and fluoroimmunoassays of the gonadotrophins.

RESULTS

Di-glycosylated glycoforms (FSHdi, LHdi) were detected in serum in addition to tetra-glycosylated FSH (FSHtetra) and tri-glycosylated LH (LHtri). FSHdi exhibited two peaks: one on day 5 to 7 and one, more pronounced, at midcycle. FSHtetra plateaued at a high concentration from day 5 to 15, without a midcycle peak. There were lower concentrations of LHdi than LHtri, except at midcycle when the opposite occurred. The mean numbers of SA and SU residues per molecule of FSH and LH in serum showed four different patterns during the cycle, all with highly significant (P < 0.0001) differences between levels at different phases of the cycle. The pattern of SA residues on FSH was 'M'-shaped, and that of SU on LH 'V'-shaped.

CONCLUSION

Serum FSH and LH governing the natural ovarian stimulation process exhibited dynamic changes of glycosylation and glycan composition. This new information on the FSH and LH molecular structures may lead to more successful mono-ovulatory treatment regimens for ovulation induction in anovulatory women.

Clinical efficacy and cost-effectiveness of HP-human FSH (Fostimon®) versus rFSH (Gonal-F®) in IVF-ICSI cycles: a meta-analysis

Clinical efficacy of human-derived follicle-stimulating hormone (FSH) versus recombinant FSH (rFSH) in IVF-ICSI cycles has long been compared, but no clear evidence of the superiority of a preparation over the other has been found. Human gonadotropins have been often grouped together, but a different glycosylation may be present in each preparation, therefore influencing the specific bioactivity. To exclude confounding factors, a meta-analysis and a cost-effectiveness analysis were designed to compare effectiveness and cost-effectiveness of a specific highly purified human FSH (HP-hFSH) (Fostimon®) versus rFSH (Gonal-F®) in IVF/ICSI cycles. Research methodology filters were applied in MEDLINE, Current Contents and Web of Science from 1980 to February 2012. Eight randomized trials met selection criteria. The meta-analysis showed no significant differences between rFSH and HP-hFSH treatment in live-birth rate (odds ratio [OR] 0.84, 95% confidence interval [CI] 0.63-1.11), clinical pregnancy rate (OR 0.85, 95% CI 0.68-1.07), number of oocytes retrieved, number of mature oocytes and days of stimulation. The cost-effectiveness ratio was € 7174 in the rFSH group and € 2056 in the HP-hFSH group. HP-hFSH is as effective as rFSH in ovarian stimulation for IVF-ICSI cycles, but the human preparation is more cost-effective.

LH supplementation in mild stimulations cycles without pituitary suppression: a retrospective analysis

A cohort of patients addressed to a mild stimulation protocol was retrospectively analysed aiming at evaluating the effect of a luteinizing hormone (LH) activity containing stimulation compared to a pure follicle-stimulating hormone (FSH) drive in absence of any pituitary suppression. Due to a referral bias, the two groups (human FSH (hFSH) n = 210; hMG n = 105) were imbalanced for age with the hFSH group (mean age 38.4) being significantly older than the hMG group (mean age 36.8). But the clinical pregnancy rates (20%) did not differ between the groups. Secondary outcome variables showed a higher number of oocytes retrieved (3.02 vs. 2.31) and higher estradiol levels (1148 vs. 820) in the hMG/younger group whereas the fertilization rate (FR) was higher (54.8 vs. 63.8) in the FSH older/group. In spite of the LH content in the hMG product (~10 IU per vial), the LH concentration on the day of human chorionic gonadotropin (hCG) was higher, although non-significantly, in the hFSH group. We suppose hCG contained in hMG inhibited to some extent the natural release of LH from the non-suppressed pituitary. Concluding, the mild stimulation clinical pregnancy rates are satisfactory independently of the treatment choice. The hMG group showed a trend for a lower efficacy. This phenomenon might be limited to non suppressed cycles, but should be taken in due account also when designing full dose controlled ovarian hyperstimulation (COH) treatments.

Randomized controlled trial comparing highly purified (HP-hCG) and recombinant hCG (r-hCG) for triggering ovulation in ART

BACKGROUND

A randomized controlled trial (RCT) comparing highly purified human Choriogonadotrophin (HP-hCG) and recombinant hCG (r-hCG) both administered subcutaneously for triggering ovulation in controlled ovarian stimulation (COS) for Assisted Reproductive Technology (ART).

METHODS

Multi-centre (n = 4), prospective, controlled, randomized, non-inferiority, parallel group, investigator blind design, including 147 patients. The trial was registered with www.clinicaltrials.gov, using the identifier: NCT00335569. The primary endpoint is the number of oocytes retrieved, while the secondary endpoints include embryo implantation, pregnancy and delivery rates as well as safety parameters.

RESULTS

The number of retrieved oocytes was not inferior when HP-hCG was used as compared to r-hCG: the mean number was 13.3 (6.8) in HP-hCG and 12.5 (5.8) in the r-hCG group (p = 0.49) with a 95% CI (-1.34, 2.77). Regarding the secondary outcomes, there were also no differences in fertilization rate at 57.3% (467/815) vs. 61.3% (482/787) (p = 0.11), the number of embryos available for transfer and cryopreservation (2PN stage) and implantation, pregnancy and delivery rates. Furthermore, there were no differences in the number and type of adverse events reported. HP-hCG was therefore not inferior to r-hCG.

CONCLUSIONS

HP-hCG and r-hCG are equally efficient and safe for triggering ovulation in ART and, both being administered subcutaneously, equally practical and well tolerated by patients.

Circulating LH/hCG receptor (LHCGR) may identify pre-treatment IVF patients at risk of OHSS and poor implantation

BACKGROUND

Successful pregnancy via in vitro fertilization (IVF) depends on the recovery of an adequate number of healthy oocytes and on blastocyst implantation following uterine transfer. Two hormones, LH and hCG, utilize a common LH/hCG receptor (LHCGR), variations in which have profound implications in human reproduction. Soluble LHCGR (sLHCGR) is released from experimental cell lines and placental explants and it can be detected in the follicular fluid and serum.

METHODS

To evaluate the impact of circulating soluble LHCGR (sLHCGR) in fertility treatment, we measured sLHCGR and LH-sLHCGR complex in serum from women seeking IVF using specifically developed quantitative enzyme-linked immunosorbent assays (ELISA). Following an IVF cycle of treatment, patients were grouped according to oocyte yield into low (lower than or equal to 7 oocytes), intermediate (8-14 oocytes) and high (greater than or equal to 15 oocytes) responders and pregnancy outcome noted.

RESULTS

Pre-treatment sLHCGR identified many women at risk of ovarian hyperstimulation. Low levels of sLHCGR were associated with pregnancy in both high and low responders but sLHCGR did not significantly affect the treatment outcome of intermediate responders. Low responders who failed to become pregnant had high levels of circulating sLHCGR bound to LH (LH-sLHCGR).

CONCLUSIONS

Pre-treatment measurement of sLHCGR could be used to tailor individual fertility treatment programs and improve outcomes by avoiding ovarian hyperstimulation and poor embryo implantation.

Deletion of Otx2 in GnRH neurons results in a mouse model of hypogonadotropic hypogonadism

GnRH is the central regulator of reproductive function responding to central nervous system cues to control gonadotropin synthesis and secretion. GnRH neurons originate in the olfactory placode and migrate to the forebrain, in which they are found in a scattered distribution. Congenital idiopathic hypogonadotropic hypogonadism (CIHH) has been associated with mutations or deletions in a number of genes that participate in the development of GnRH neurons and expression of GnRH. Despite the critical role of GnRH in mammalian reproduction, a comprehensive understanding of the developmental factors that are responsible for regulating the establishment of mature GnRH neurons and the expression of GnRH is lacking. orthodenticle homeobox 2 (OTX2), a homeodomain protein required for the formation of the forebrain, has been shown to be expressed in GnRH neurons, up-regulated during GnRH neuronal development, and responsible for increased GnRH promoter activity in GnRH neuronal cell lines. Interestingly, mutations in Otx2 have been associated with human hypogonadotropic hypogonadism, but the mechanism by which Otx2 mutations cause CIHH is unknown. Here we show that deletion of Otx2 in GnRH neurons results in a significant decrease in GnRH neurons in the hypothalamus, a delay in pubertal onset, abnormal estrous cyclicity, and infertility. Taken together, these data provide in vivo evidence that Otx2 is critical for GnRH expression and reproductive competence.

Evidence that obesity and androgens have independent and opposing effects on gonadotropin production from puberty to maturity

Optimal fat mass is necessary for normal gonadotropin levels in adults, and both undernutrition and overnutrition suppress gonadotropins: thus, the gonadotropin response to relative adipose mass is biphasic. Adult obesity is associated with blunted luteinizing hormone (LH) pulse amplitude that is partially attributable to increased LH clearance rate. Testosterone appears to have a biphasic effect on gonadotropin production in females. Moderate elevations of testosterone appear to stimulate LH production at both the hypothalamic and pituitary level, while very high levels of testosterone suppress LH. Thus, obesity per se appears to suppress gonadotropin production, and moderate hyperandrogenemia in women appears to stimulate LH. The ordinary hypergonadotropic hyperandrogenism of obese women appears to be an exception to this model because it is usually due to polycystic ovary syndrome (PCOS), a condition in which intrinsic functional ovarian hyperandrogenism and excess adiposity share a common origin that involves insulin-resistant hyperinsulinemia. LH elevation seems to be secondary to hyperandrogenemia and is absent in the most obese cases. Overweight early pubertal girls have significant blunting of sleep-related LH production, which is the first hormonal change of puberty. The data are compatible with the possibility that excess adiposity may paradoxically subtly suppress hypothalamic-pituitary-gonadal function in early puberty although it is known to contribute to the early onset of puberty.

Effects of 17beta-oestradiol and norethisterone acetate on sulfonation and sialylation of gonadotrophins in post-menopausal women

BACKGROUND

The number of terminal sialic acid and sulfonated N-acetylgalactosamine (SO(3)-GalNAc) on gonadotrophins in serum varies during the menstrual cycle and changes at menopause, suggesting that gonadal steroids modify their oligosaccharide synthesis. Our objective was to determine the effects of 17beta-oestradiol (E(2)) and a progestogen, norethisterone acetate (NETA), on the sulfonation and sialylation of gonadotrophins in post-menopausal women.

METHODS

Serum samples were obtained from eight post-menopausal women treated with 20 mg E(2) implants every 6 months, from four women who in addition were treated daily with 5 mg NETA orally for a 2-week period, and from four women who got this NETA treatment during a 4-week period. Sera from 11 non-treated post-menopausal women served as a reference group. The gonadotrophin serum concentrations, the number of SO(3)-GalNAc and sialic acid residues per serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) molecule, and the distributions of molecules with 0-1-2-3-4 sulfonated residues were measured.

RESULTS

The E(2)-treated post-menopausal women had considerably less (P < 0.001) sialic acid and slightly more (P < 0.01) SO(3)-GalNAc per serum LH and FSH molecule than the non-treated. Two weeks of NETA treatment increased the sulfonation of LH (P < 0.01) and FSH (P < 0.05) concomitantly with decreased (P < 0.05) sialylation of LH.

CONCLUSION

The primary effect of E(2) treatment was a decrease in sialylation and, due to competition for the same substrate, a secondary and consequentially minor increase in sulfonation of LH and FSH. The primary effect of the NETA therapy was an increase in the sulfonation of LH and FSH concomitantly with secondary and consequentially decreases in sialylation of LH.

The common genetic variant of luteinizing hormone has a longer serum half-life than the wild type in heterozygous women

CONTEXT

The common genetic variant of human LH has two mutations and an extra N-linked oligosaccharide chain, a modification expected to affect the half-life in the circulation.

OBJECTIVES

Our objectives were to determine the half-lives of variant and wild-type forms of LH during GnRH receptor blockade in heterozygous women and to determine the time-related changes in isoform composition.

DESIGN AND PARTICIPANTS

Serum samples were obtained from three healthy women heterozygous for variant LH before and up to 20 h after administration of the NAL-GLU GnRH antagonist.

MAIN OUTCOME MEASURES

The half-lives were estimated by monoexponential decay. The number of sialic acid and sulfonated N-acetylgalactosamine residues per wild-type and variant LH molecule and the distribution of molecules with zero, one, two, or three sulfonated residues were measured.

RESULTS

The variant LH had a half-life that was approximately 40% longer than the corresponding forms of wild-type LH (148 vs. 108 min; P < 0.001). Variant LH had more sialic acid residues per molecule than wild type (3.6 vs. 2.4; P < 0.05), whereas the number of sulfonated residues was similar (1.0 vs. 0.98). The decline in the variant LH during GnRH receptor blockade was associated with a decrease in sulfonated and an increase in sialic acid residues similar to that for in wild-type LH. Isoforms of either variant or wild-type LH with two to three sulfonate groups per molecule had the shortest half-life.

CONCLUSION

Variant LH remains longer in circulation than wild type during GnRH receptor blockade in heterozygous women, in accord with its higher content of sialic acid.

Rerouting of a follicle-stimulating hormone analog to the regulated secretory pathway

LH and FSH are produced by the same gonadotrope cells of the anterior pituitary but differ in their mode of secretion. This coordinated secretion of LH and FSH is essential for normal follicular development and ovulation in females and for spermatogenesis in males. The structural signals encoded in the LH and FSH subunits that govern the intracellular sorting of LH through the regulated secretory pathway and FSH through the constitutive pathway are largely unknown. Our laboratory recently identified the seven amino acid carboxy tail of LH beta as a sorting signal for LH in GH(3) cells. Here we compared the morphological features of GH(3) cells expressing an FSH analog containing the heptapeptide (FL7AA) with wild-type FSH using confocal microscopy. These experiments were performed to develop a rerouting model for examining structure-function links between secretion pathways of FSH/LH and their biological action. Both FSH- and LH-expressing cells exhibit a fluorescence pattern of randomly dispersed cytoplasmic puncta. FL7AA expressing cells have more intracellular accumulation compared with wild-type FSH and display a unique halo pattern of fluorescence near the plasma membrane. Such a pattern was not observed in cells expressing FSH or LH. Our results demonstrate that this FSH analog containing the carboxy heptapeptide of LH beta is rerouted to the regulated secretory pathway in GH(3) cells. This rerouted gonadotropin provides a unique model to study the trafficking, regulation, and function of LH and FSH.

Sulfation of LH does not affect intracellular trafficking

LH and FSH are produced by the same gonadotrope cells of the anterior pituitary but differ in their mode of secretion. LH secretion is primarily episodic, or regulated, while FSH secretion is primarily basal, or constitutive. The asparagine (N)-linked oligosaccharides of LH and FSH terminate with sulfate and sialic acid, respectively. TSH also contains sulfated N-linked oligosaccharides and is secreted through the regulated pathway. It has been hypothesized that sulfate plays a role in segregating LH to the regulated pathway. Using a mouse pituitary model, we tested this hypothesis by examining the secretory fate of LH from pituitaries treated with sodium chlorate, a known inhibitor of sulfation. Here we show that mouse LH is sulfated and secreted through the regulated pathway, while FSH is secreted constitutively. LH secretion from chlorate-treated pituitaries, which showed complete inhibition of sulfation, was similar to untreated pituitaries. These data suggest that the metabolic role for sulfated N-linked oligosaccharides is not for intracellular trafficking but for the extracellular bioactivity of LH.