FSH-receptor isoforms and FSH-dependent gene transcription in human monocytes and osteoclasts

Extragonadal function of follicle-stimulating hormone: Evidence for a role in endothelial physiology and dysfunction

AIMS

Follicle-stimulating hormone (FSH) plays a fundamental role in reproduction stimulating ovarian folliculogenesis, Sertoli cells function and spermatogenesis. However, the recent identification of FSH receptor (FSHR) also in extra-gonadal tissues has suggested that FSH activity may not be limited only to fertility regulation, with conflicting results on the possible role of FSH in endothelial cells. The aim of this study was to investigate FSH role on endothelial function in Human Umbilical Vein Endothelial Cells (HUVECs).

RESULTS

Endothelial Nitric oxide synthase (eNOS) expression, eNOS phosphorylation and Nitric Oxide (NO) production resulted increased after the stimulation of HUVEC with recombinant human FSH (rhFSH) at 3.6x103 ng/ml, with increasing Calcium release from intracellular stores. Furthermore, IP3 production increased after rhFSH stimulation despite PTX treatment and NFAT1 was observed prevalently in nucleus. We observed a statistical difference between untreated cells and cells stimulated with 0.36x103 ng/ml and between cells stimulated with 0.36x103 ng/ml and cells stimulated with 1.8x103 ng/ml at 4 and 8 h by Wound healing assay, respectively. Furthermore, a higher cellular permeability was observed in stimulated cells, with atypical VE-cadherin distribution, as well as filamentous actin.

CONCLUSIONS

Our findings suggest that FSH at high concentrations elicits a signalling that could compromise the endothelial membrane. Indeed, VE-cadherin anomalies may severely affect the endothelial barrier, resulting in an increased membrane permeability. Although NO is an important vasodilatation factor, probably an excessive production could impact on endothelial functionality, partially explaining the increased risk of cardiovascular diseases in menopausal women and men with hypogonadism.

Neuroendocrinology of bone

The past decade has witnessed significant advances in our understanding of skeletal homeostasis and the mechanisms that mediate the loss of bone in primary and secondary osteoporosis. Recent breakthroughs have primarily emerged from identifying disease-causing mutations and phenocopying human bone disease in rodents. Notably, using genetically-modified rodent models, disrupting the reciprocal relationship with tropic pituitary hormone and effector hormones, we have learned that pituitary hormones have independent roles in skeletal physiology, beyond their effects exerted through target endocrine glands. The rise of follicle-stimulating hormone (FSH) in the late perimenopause may account, at least in part, for the rapid bone loss when estrogen is normal, while low thyroid-stimulating hormone (TSH) levels may contribute to the bone loss in thyrotoxicosis. Admittedly speculative, suppressed levels of adrenocorticotropic hormone (ACTH) may directly exacerbate bone loss in the setting of glucocorticoid-induced osteoporosis. Furthermore, beyond their established roles in reproduction and lactation, oxytocin and prolactin may affect intergenerational calcium transfer and therefore fetal skeletal mineralization, whereas elevated vasopressin levels in chronic hyponatremic states may increase the risk of bone loss.. Here, we discuss the interaction of each pituitary hormone in relation to its role in bone physiology and pathophysiology.

Pituitary crosstalk with bone, adipose tissue and brain

Traditional textbook physiology has ascribed unitary functions to hormones from the anterior and posterior pituitary gland, mainly in the regulation of effector hormone secretion from endocrine organs. However, the evolutionary biology of pituitary hormones and their receptors provides evidence for a broad range of functions in vertebrate physiology. Over the past decade, we and others have discovered that thyroid-stimulating hormone, follicle-stimulating hormone, adrenocorticotropic hormone, prolactin, oxytocin and arginine vasopressin act directly on somatic organs, including bone, adipose tissue and liver. New evidence also indicates that pituitary hormone receptors are expressed in brain regions, nuclei and subnuclei. These studies have prompted us to attribute the pathophysiology of certain human diseases, including osteoporosis, obesity and neurodegeneration, at least in part, to changes in pituitary hormone levels. This new information has identified actionable therapeutic targets for drug discovery.

Osteoporosis and bone metabolism in patients with Klinefelter syndrome

Low bone mass is common in men with Klinefelter syndrome (KS), with a prevalence of 6-15% of osteoporosis and of 25-48% of osteopenia. Reduced bone mass has been described since adolescence and it might be related to both reduced bone formation and higher bone resorption. Although reduced testosterone levels are clearly involved in the pathogenesis, this relation is not always evident. Importantly, fracture risk is increased independently from bone mineral density (BMD) and testosterone levels. Here we discuss the pathogenesis of osteoporosis in patients with KS, with a particular focus on the role of testosterone and testis function. In fact, other hormonal mechanisms, such as global Leydig cell dysfunction, causing reduced insulin-like factor 3 and 25-OH vitamin D levels, and high follicle-stimulating hormone and estradiol levels, might be involved. Furthermore, genetic aspects related to the supernumerary X chromosome might be involved, as well as androgen receptor expression and function. Notably, body composition, skeletal mass and strength, and age at diagnosis are other important aspects. Although dual-energy x-ray absorptiometry is recommended in the clinical workflow for patients with KS to measure BMD, recent evidence suggests that alterations in the microarchitecture of the bones and vertebral fractures might be present even in subjects with normal BMD. Therefore, analysis of trabecular bone score, high-resolution peripheral quantitative computed tomography and vertebral morphometry seem promising tools to better estimate the fracture risk of patients with KS. This review also summarizes the evidence on the best available treatments for osteoporosis in men with KS, with or without hypogonadism.

Investigational follicle-stimulating hormone receptor agonists for male infertility therapy

INTRODUCTION

According to estimates by the World Health Organization, about 17.5% of the adult population - roughly 1 in 6 globally - experience infertility. The causes of male infertility remain poorly understood and have yet to be fully evaluated. Follicle-stimulating hormone (FSH) represents an available and useful therapeutic strategy for the treatment of idiopathic infertility.

AREAS COVERED

We provide here an overview of the molecular mechanisms by which FSH stimulates Sertoli cells and the schemes, dosages, and formulations of FSH most prescribed so far and reported in the literature. We also evaluated the possible predictor factors of the response to FSH administration and the indications of the latest guidelines on the use of FSH for the treatment of male infertility.

EXPERT OPINION

FSH therapy should be considered for infertile male patients with oligoasthenoteratozoospermia and normal serum FSH levels to quantitatively and qualitatively improve sperm parameters and pregnancy and birth rates. The grade of evidence is very low to low, due to the limited number of randomized controlled studies and patients available, the heterogeneity of the studies, and the limited effect size. To overcome these limitations, preclinical and clinical research is needed to evaluate the most effective dose and duration of FSH administration.

C/EBPβ/AEP Signaling Drives Alzheimer's Disease Pathogenesis

Alzheimer's disease (AD) is the most common type of dementia. Almost two-thirds of patients with AD are female. The reason for the higher susceptibility to AD onset in women is unclear. However, hormone changes during the menopausal transition are known to be associated with AD. Most recently, we reported that follicle-stimulating hormone (FSH) promotes AD pathology and enhances cognitive dysfunctions via activating the CCAAT-enhancer-binding protein (C/EBPβ)/asparagine endopeptidase (AEP) pathway. This review summarizes our current understanding of the crucial role of the C/EBPβ/AEP pathway in driving AD pathogenesis by cleaving multiple critical AD players, including APP and Tau, explaining the roles and the mechanisms of FSH in increasing the susceptibility to AD in postmenopausal females. The FSH-C/EBPβ/AEP pathway may serve as a novel therapeutic target for the treatment of AD.

Extra-Gonadal and Non-Canonical Effects of FSH in Males

Recombinant follicle-stimulating hormone (FSH) is commonly used for the treatment of female infertility and is increasingly being used in males as well, as recommended by notable guidelines. FSH is composed of an α subunit, shared with other hormones, and a β subunit, which confers specificity of biological action by interacting with its surface receptor (FSHR), predominantly located in granulosa and Sertoli cells. However, FSHRs also exist in extra-gonadal tissues, indicating potential effects beyond male fertility. Emerging evidence suggests that FSH may have extra-gonadal effects, including on bone metabolism, where it appears to stimulate bone resorption by binding to specific receptors on osteoclasts. Additionally, higher FSH levels have been associated with worse metabolic and cardiovascular outcomes, suggesting a possible impact on the cardiovascular system. FSH has also been implicated in immune response modulation, as FSHRs are expressed on immune cells and may influence inflammatory response. Furthermore, there is growing interest in the role of FSH in prostate cancer progression. This paper aims to provide a comprehensive analysis of the literature on the extra-gonadal effects of FSH in men, with a focus on the often-conflicting results reported in this field. Despite the contradictory findings, the potential for future development in this area is substantial, and further research is needed to elucidate the mechanisms underlying these effects and their clinical implications.

Exploring the expression and potential function of follicle stimulating hormone receptor in extragonadal cells related to abdominal aortic aneurysm

INTRODUCTION

Follicle stimulating hormone (FSH) is identified to play a role in postmenopausal disease and hypothesized to affect abdominal aortic aneurysm (AAA) onset/progression in postmenopausal women. We aimed to detect FSHR gene expression in AAA tissue and cell types involved in AAA formation.

METHODS

FSH stimulation of human umbilical cord endothelial cells (HUVECs), smooth muscle cells (HUCs) and PMA-differentiated macrophages to assess gene expression of FSHR and various markers. Human macrophages activated with various stimuli were assessed for FSHR gene expression. AAA dataset, AAA tissue samples and AAA-derived smooth muscle cells (SMC) obtained from elderly female donors were assessed for FSHR gene expression. AAA-SMCs were stimulated with FSH to assess its effect on gene expression. Lastly, oxidized low-density-lipoprotein (ox-LDL) uptake and abundance of cell surface protein markers were assessed by flow cytometry after FSH stimulation of human monocytes.

RESULTS

FSH stimulation showed similar levels of gene expression in HUVECs and HUCs. Only ACTA2 was downregulated in HUCs. In PMA-differentiated macrophages, gene expression of inflammation markers was unchanged after FSH stimulation. FSHR gene expression was found to be low in the AAA datasets. Female AAA-SMCs show occasional FSHR gene expression at a very low level, yet stimulation with FSH did not affect gene expression of SMC- or inflammation markers. FSH stimulation did not impact ox-LDL uptake or alter cell surface protein expression in monocytes. While FSHR gene expression was detected in human testis tissue, it was below quantification level in all other investigated cell types, even upon activation of macrophages with various stimuli.

CONCLUSION

Despite previous reports, we did not detect FSHR gene expression in various extragonadal cell types, except in occasional female AAA-SMCs. No clear effect on cell activation was observed upon FSH stimulation in any cell type. Our data suggest that a direct effect of FSH in AAA-related extragonadal cells is unlikely to influence AAA.

Associations of LH and FSH with reproductive hormones depending on each stage of the menopausal transition

INTRODUCTION

Associations of luteinizing hormone (LH) with androgens during the menopausal transition and associations between follicle-stimulating hormone (FSH) levels and various diseases related to reproductive hormones in postmenopause have received much attention. LH and FSH are also known to be associated with activities of enzymes related to reproductive hormones. We examined the associations of LH and FSH with androgens and estrogens in each stage of the menopausal transition according to a classification from menopausal transition to postmenopause.

METHODS

This study was a cross-sectional design. We basically used the Stage of Reproductive Aging Workshop (STRAW) + 10. We divided the 173 subjects into 6 groups according to menstrual regularity and follicle-stimulating hormone level: mid reproductive stage (Group A), late reproductive stage (Group B), early menopausal transition (Group C), late menopausal transition (Group D), very early postmenopause (Group E) and early postmenopause (Group F). Levels of LH, FSH, dehydroepiandrosterone sulfate (DHEAS), estradiol, estrone, testosterone (T), free T, androstenedione and androstenediol were measured.

RESULTS

In Group A, LH showed significant positive correlations with androstenedione and estrone. In Group D, LH was positively associated with T and free T and was negatively associated with estradiol. In Groups B, C, D and F, LH showed significant positive correlations with FSH, and there was a tendency for an association between LH and FSH in Group E. FSH was associated with estradiol but not with estrone in Groups C and D.

CONCLUSION

The associations of LH and FSH with reproductive hormones are different depending on the stage of the menopausal transition.

TRIAL REGISTRATION

Trial registration number 2356-1; Date of registration: 18/02/2018, retrospectively registered.

Bones and Hormones: Interaction between Hormones of the Hypothalamus, Pituitary, Adipose Tissue and Bone

The bony skeleton, as a structural foundation for the human body, is essential in providing mechanical function and movement. The human skeleton is a highly specialized and dynamic organ that undergoes continuous remodeling as it adapts to the demands of its environment. Advances in research over the last decade have shone light on the various hormones that influence this process, modulating the metabolism and structural integrity of bone. More recently, novel and non-traditional functions of hypothalamic, pituitary, and adipose hormones and their effects on bone homeostasis have been proposed. This review highlights recent work on physiological bone remodeling and discusses our knowledge, as it currently stands, on the systemic interplay of factors regulating this interaction. In this review, we provide a summary of the literature on the relationship between bone physiology and hormones including kisspeptin, neuropeptide Y, follicle-stimulating hormone (FSH), prolactin (PRL), adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), growth hormone (GH), leptin, and adiponectin. The discovery and understanding of this new functionality unveils an entirely new layer of physiologic circuitry.

Follicle-stimulating hormone is associated with low bone mass in postmenopausal women

We evaluated the influence of two endogenous hormones on bone health in older women. Higher FSH was associated with bone disease, especially in lower estradiol environments. FSH attenuated the relationship between estradiol and bone. This may provide a mechanism through which future clinical research intervenes on bone loss.

INTRODUCTION/PURPOSE

Despite preclinical evidence for an inverse association of follicle-stimulating hormone (FSH) and bone mineral density (BMD), no large epidemiologic studies have evaluated the separate and joint influences of FSH and estradiol on bone in postmenopausal women.

METHODS

In a cross-sectional study of 675 postmenopausal women, we evaluated associations of serum FSH and dual X-ray absorptiometry (DXA)-classified areal BMD as well as low bone mass or osteoporosis (T-score <  - 1.0) of the femoral neck and total hip. We stratified this analysis by serum estradiol (cut at the median). We tested whether FSH mediates the association of estradiol and BMD using the Sobel test.

RESULTS

In linear regression models, there was a significant inverse association of serum FSH with both femoral neck and total hip BMD (both p < 0.01) when adjusted for age, hormone therapy (HT) use, and diabetes. In fully adjusted logistic regression models, women in the highest FSH tertile had higher odds of low bone mass/osteoporosis at the femoral neck (OR = 2.98; 95% CI = 1.86-4.77) and at the total hip (OR = 1.74; 95% CI = 1.06-2.84) compared to those in the lowest FSH tertile. We report evidence of effect modification by estradiol in stratified models and an interaction term. FSH met all criteria of a mediator, including an estimated 70% attenuation of the estradiol-BMD relationship (Sobel p value < 0.001).

CONCLUSIONS

FSH is associated with higher odds of having low bone mass/osteoporosis even after accounting for HT use. FSH is a mediator of the relationship between estradiol and BMD in healthy postmenopausal women. Larger, prospective studies of FSH concentrations and bone health are needed.

Effects of Follicle-Stimulating Hormone on Human Sperm Motility In Vitro

To evaluate whether the follicle-stimulating hormone (FSH) receptor (FSHR) is expressed in human spermatozoa and the effects of FSH incubation on sperm function. Twenty-four Caucasian men were recruited. Thirteen patients had asthenozoospermia, and the remaining 11 had normal sperm parameters (controls). After confirming FSHR expression, spermatozoa from patients and controls were incubated with increasing concentrations of human purified FSH (hpFSH) to reassess FSHR expression and localization and to evaluate progressive and total sperm motility, the mitochondrial membrane potential, and protein kinase B (AKT) 473 and 308 phosphorylation. FSHR is expressed in the post-acrosomal segment, neck, midpiece, and tail of human spermatozoa. Its localization does not differ between patients and controls. Incubation with hpFSH at a concentration of 30 mIU/mL appeared to increase FSHR expression mainly in patients. Incubation of human spermatozoa with hpFSH overall resulted in an overall deterioration of both progressive and total motility in patients and controls and worse mitochondrial function only in controls. Finally, incubation with FSH increased AKT473/tubulin phosphorylation to a greater extent than AKT308. FSHR is expressed in the post-acrosomal region, neck, midpiece, and tail of human spermatozoa. Contrary to a previous study, we report a negative effect of FSH on sperm motility and mitochondrial function. FSH also activates the AKT473 signaling pathway.

Non-reproductive effects of follicle-stimulating hormone in young men

OBJECTIVE

Follicle-stimulating hormone (FSH) receptor expression has been reported in many extra-gonadal tissues, raising the question of non-reproductive effects of FSH. Because of increasing usage of FSH in treatment of male infertility, deeper knowledge of possible harmful off-target effects of FSH is warranted.

METHODS

In total, 33 healthy young men (mean age 30 years) were included in the study. All received an s.c. injection of gonadotropin-releasing hormone (GnRH) antagonist and n = 16 were randomized to 300 IU recombinant FSH (300 IE 3 times/week) for 5 weeks at first visit (V1) whereas n = 17 served as controls. Blood samples were taken at (V1), after 3 weeks (V2), and after 5 weeks (V3), when the study ended. At V2, all subjects received 1000 mg testosterone undecanoate i.m. A standard set of bio- and inflammatory markers were compared between the groups using the Mann-Whitney test adjusted for multiple testing.

RESULTS

As compared to controls, the FSH treated men had higher SHBG and albumin concentrations at V2 (p = 0.024 and 0.027, respectively), and lower levels of alanine aminotransferase (p = 0.026) and magnesium (p = 0.028) at V3. However, none of the results remained statistically significant after Bonferroni correction (p > 0.0011).

CONCLUSIONS

FSH had no significant effects on non-reproductive organs when given in standard therapeutic doses to young men for 5 weeks. Therefore, the FSH treatment can be considered safe in otherwise healthy young men, constituting candidates for the infertility treatment with FSH.

Altered GnRH neuron and ovarian innervation characterize reproductive dysfunction linked to the Fragile X messenger ribonucleoprotein (Fmr1) gene mutation

Introduction

Mutations in the Fragile X Messenger Ribonucleoprotein 1 (FMR1) gene cause Fragile X Syndrome, the most common monogenic cause of intellectual disability. Mutations of FMR1 are also associated with reproductive disorders, such as early cessation of reproductive function in females. While progress has been made in understanding the mechanisms of mental impairment, the causes of reproductive disorders are not clear. FMR1-associated reproductive disorders were studied exclusively from the endocrine perspective, while the FMR1 role in neurons that control reproduction was not addressed.

Results

Here, we demonstrate that similar to women with FMR1 mutations, female Fmr1 null mice stop reproducing early. However, young null females display larger litters, more corpora lutea in the ovaries, increased inhibin, progesterone, testosterone, and gonadotropin hormones in the circulation. Ovariectomy reveals both hypothalamic and ovarian contribution to elevated gonadotropins. Altered mRNA and protein levels of several synaptic molecules in the hypothalamus are identified, indicating reasons for hypothalamic dysregulation. Increased vascularization of corpora lutea, higher sympathetic innervation of growing follicles in the ovaries of Fmr1 nulls, and higher numbers of synaptic GABAA receptors in GnRH neurons, which are excitatory for GnRH neurons, contribute to increased FSH and LH, respectively. Unmodified and ovariectomized Fmr1 nulls have increased LH pulse frequency, suggesting that Fmr1 nulls exhibit hyperactive GnRH neurons, regardless of the ovarian feedback.

Conclusion

These results reveal Fmr1 function in the regulation of GnRH neuron secretion, and point to the role of GnRH neurons, in addition to the ovarian innervation, in the etiology of Fmr1-mediated reproductive disorders.

Bone circuitry and interorgan skeletal crosstalk

The past decade has seen significant advances in our understanding of skeletal homeostasis and the mechanisms that mediate the loss of bone integrity in disease. Recent breakthroughs have arisen mainly from identifying disease-causing mutations and modeling human bone disease in rodents, in essence, highlighting the integrative nature of skeletal physiology. It has become increasingly clear that bone cells, osteoblasts, osteoclasts, and osteocytes, communicate and regulate the fate of each other through RANK/RANKL/OPG, liver X receptors (LXRs), EphirinB2-EphB4 signaling, sphingolipids, and other membrane-associated proteins, such as semaphorins. Mounting evidence also showed that critical developmental pathways, namely, bone morphogenetic protein (BMP), NOTCH, and WNT, interact each other and play an important role in postnatal bone remodeling. The skeleton communicates not only with closely situated organs, such as bone marrow, muscle, and fat, but also with remote vital organs, such as the kidney, liver, and brain. The metabolic effect of bone-derived osteocalcin highlights a possible role of skeleton in energy homeostasis. Furthermore, studies using genetically modified rodent models disrupting the reciprocal relationship with tropic pituitary hormone and effector hormone have unraveled an independent role of pituitary hormone in skeletal remodeling beyond the role of regulating target endocrine glands. The cytokine-mediated skeletal actions and the evidence of local production of certain pituitary hormones by bone marrow-derived cells displays a unique endocrine-immune-skeletal connection. Here, we discuss recently elucidated mechanisms controlling the remodeling of bone, communication of bone cells with cells of other lineages, crosstalk between bone and vital organs, as well as opportunities for treating diseases of the skeleton.

Inadequate detection of the FSHR complicates future research on extragonadal FSHR localization

INTRODUCTION

Recently, follicle stimulating hormone (FSH) through interaction with its receptor (FSHR) has been proposed to play a role in postmenopausal osteoporosis and cardiovascular disease, rather than the loss of estrogen. To explore this hypothesis, unravelling which cells express extragonadal FSHR on protein level is key.

METHODS

We used two commercial anti-FSHR antibodies and validated them by performing immunohistochemistry on positive (ovary, testis) and negative controls (skin).

RESULTS

The monoclonal anti-FSHR antibody could not identify the FSHR in ovary or testis. The polyclonal anti-FSHR antibody stained the granulosa cells (ovary) and Sertoli cells (testis), yet there was equally intense staining of other cells/extracellular matrix. Furthermore, the polyclonal anti-FSHR antibody also stained skin tissue extensively, suggesting that the antibody stains more than just FSHR.

DISCUSSION

The findings in this study may add accuracy to literature on extragonadal FSHR localization and warrants attention to the use of inadequate anti-FSHR antibodies to value the potential role of FSH/FSHR in postmenopausal disease.

Osteoporosis and Alveolar Bone Health in Periodontitis Niche: A Predisposing Factors-Centered Review

Periodontitis is a periodontal inflammatory condition that results from disrupted periodontal host-microbe homeostasis, manifested by the destruction of tooth-supporting structures, especially inflammatory alveolar bone loss. Osteoporosis is characterized by systemic deterioration of bone mass and microarchitecture. The roles of many systemic factors have been identified in the pathogenesis of osteoporosis, including endocrine change, metabolic disorders, health-impaired behaviors and mental stress. The prevalence rate of osteoporotic fracture is in sustained elevation in the past decades. Recent studies suggest that individuals with concomitant osteoporosis are more vulnerable to periodontal impairment. Current reviews of worse periodontal status in the context of osteoporosis are limited, mainly centering on the impacts of menopausal and diabetic osteoporosis on periodontitis. Herein, this review article makes an effort to provide a comprehensive view of the relationship between osteoporosis and periodontitis, with a focus on clarifying how those risk factors in osteoporotic populations modify the alveolar bone homeostasis in the periodontitis niche.

Independent Skeletal Actions of Pituitary Hormones

Over the past years, pituitary hormones and their receptors have been shown to have non-traditional actions that allow them to bypass the hypothalamus-pituitary-effector glands axis. Bone cells-osteoblasts and osteoclasts-express receptors for growth hormone, follicle stimulating hormone (FSH), thyroid stimulating hormone (TSH), adrenocorticotrophic hormone (ACTH), prolactin, oxytocin, and vasopressin. Independent skeletal actions of pituitary hormones on bone have been studied using genetically modified mice with haploinsufficiency and by activating or inactivating the receptors pharmacologically, without altering systemic effector hormone levels. On another front, the discovery of a TSH variant (TSH-βv) in immune cells in the bone marrow and skeletal action of FSHβ through tumor necrosis factor α provides new insights underscoring the integrated physiology of bone-immune-endocrine axis. Here we discuss the interaction of each pituitary hormone with bone and the potential it holds in understanding bone physiology and as a therapeutic target.

Combined Therapy of Yishen Zhuanggu Decoction and Caltrate D600 Alleviates Postmenopausal Osteoporosis by Targeting FoxO3a and Activating the Wnt/β-Catenin Pathway

Background

Postmenopausal osteoporosis (PMO) is the most prevalent metabolic bone disease in women. Yishen Zhuanggu (YSZG) decoction and Caltrate D600 reportedly affects bone formation. This study aimed to investigate the efficacy and mechanism of YSZG decoction combined with Caltrate D600 in PMO treatment.

Methods

Ovariectomy-induced PMO rat model was treated with YSZG or/and Caltrate D600 for 12 weeks. Femur bone mineral density (BMD), osteoporosis-related protein expression, and serum parameters were measured. Pathological features of femur bone tissues were observed using hematoxylin and eosin staining. Serum levels of oxidative stress parameters were measured using corresponding commercial kits. The mRNA and protein expression of FoxO3a, Wnt, and β-catenin was detected using qRT-PCR and western blotting.

Results

The BMD and ultimate load of PMO rats were increased after treatment with YSZG. YSZG treatment promoted the bone trabeculae formation of PMO rats. YSZG treatment also induced bone differentiation and suppress oxidative stress in PMO rats, evidenced by the increased BALP, Runx2, OPG, SOD, and CAT levels, as well as the decreased TRACP 5b, RANKL, ROS, and MDA levels. Additionally, YSZG treatment downregulated the FoxO3a expression and upregulated the levels of Wnt and β-catenin in PMO rats. Caltrate D600 addition showed an auxiliary effect for YSZG.

Conclusion

YSZG decoction exerts the antiosteoporotic effect on PMO by restraining the FoxO3a expression and activating the Wnt/β-catenin pathway, which has an impressive synergistic effect with Caltrate D600.

Tumor necrosis factor-alpha stimulated gene-6: A biomarker reflecting disease activity in rheumatoid arthritis

BACKGROUND

To explore the serum tumor necrosis factor-alpha stimulated gene-6 (TSG-6) level and its association with disease activity in rheumatoid arthritis (RA) patients.

METHODS

We recruited 176 RA patients, 178 non-RA patients (lupus erythematosus, osteoarthritis, ulcerative colitis, ankylosing spondylitis and psoriasis) and 71 healthy subjects. Serum TSG-6 levels were detected by enzyme-linked immunosorbent assay (ELISA). RA patients were divided into inactive RA and active RA groups by disease activity score of 28 joints based on C-reactive protein (DAS28-CRP). The receiver operating characteristic (ROC) curve and Spearman's rank correlation test analyzed the correlation between TSG-6 concentration and RA disease activity.

RESULTS

Tumor necrosis factor-alpha stimulated gene-6 levels in the RA group were increased (p < 0.01). TSG-6 concentrations indicated an upward tendency with increased disease activity; The area under the curve (AUC) of TSG-6 for diagnosing RA and assessing the severity of RA were 0.78 and 0.80, respectively; The combination of TSG-6 and anti-mutated citrullinated vimentin antibodies (anti-MCV) (sensitivity:98.4%)improved the diagnostic accuracy of RA. Binary logistic regression analysis showed that TSG-6 was an independent risk factor related to the severity of RA, and OR (95% CI) was 1.2 (1.003-1.453).

CONCLUSION

The TSG-6 levels in RA patients were elevated and related to disease activity. Therefore, TSG-6 may serve as a new potential biomarker for evaluating RA disease activity.

Transcription of the Envelope Protein by 1-L Protein-RNA Recognition Code Leads to Genes/Proteins That Are Relevant to the SARS-CoV-2 Life Cycle and Pathogenesis

The theoretical protein-RNA recognition code was used in this study to research the compatibility of the SARS-CoV-2 envelope protein (E) with mRNAs in the human transcriptome. According to a review of the literature, the spectrum of identified genes showed that the virus post-transcriptionally promotes or represses the genes involved in the SARS-CoV-2 life cycle. The identified genes/proteins are also involved in adaptive immunity, in the function of the cilia and wound healing (EMT and MET) in the pulmonary epithelial tissue, in Alzheimer's and Parkinson's disease and in type 2 diabetes. For example, the E-protein promotes BHLHE40, which switches off the IL-10 inflammatory "brake" and inhibits antiviral THαβ cells. In the viral cycle, E supports the COPII-SCAP-SREBP-HSP90α transport complex by the lowering of cholesterol in the ER and by the repression of insulin signaling, which explains the positive effect of HSP90 inhibitors in COVID-19 (geldanamycin), and E also supports importin α/β-mediated transport to the nucleus, which explains the positive effect of ivermectin, a blocker of importins α/β. In summary, transcription of the envelope protein by the 1-L protein-RNA recognition code leads to genes/proteins that are relevant to the SARS-CoV-2 life cycle and pathogenesis.

Follicle-stimulating hormone and blood lead levels with bone mineral density and the risk of fractures in pre- and postmenopausal women

BACKGROUND

The conclusions on the associations of serum follicle-stimulating hormone (FSH) and blood lead levels with bone mineral density (BMD) were controversial. Furthermore, little was known on the impacts of co-existence of serum FSH and blood lead levels on BMD and the risk of fractures in premenopausal and postmenopausal women. Therefore, the present study aimed to examine the associations of serum FSH and blood lead levels with BMD and the risk of fractures in premenopausal and postmenopausal women.

METHODS

Data were derived from the National Health and Nutrition Examination Survey. FSH is assayed using the Microparticle Enzyme Immunoassay technology. Blood lead levels were measured using atomic absorption spectrometry. BMD was measured using dual energy X-ray absorptiometry. Fractures were defined as subjects with fractures in any site of hip, wrist, and spine.

RESULTS

This study included 3798 participants. Elevated blood lead levels were associated with increased serum FSH levels (β= 48.22, 95% CI: 40.21~ 56.22). Serum FSH levels were negatively associated with total femur BMD in pre- and postmenopausal women. However, elevated serum FSH levels were associated with a lower lumbar spine BMD and a higher risk of fractures only in postmenopausal women (β= -0.0010, 95% CI: -0.0015~ -0.0006; OR: 1.007, 95% CI: 1.000~1.014, respectively).

CONCLUSIONS

Serum lead levels were associated with serum FSH levels. Serum FSH levels were associated with a lower BMD and a higher risk of fractures.

Circulating osteogenic progenitors and osteoclast precursors are associated with long-term glycemic control, sex steroids, and visceral adipose tissue in men with type 2 diabetes mellitus

INTRODUCTION

Type 2 diabetes mellitus (T2DM) is well-known to be associated with normal bone density but, concurrently, low bone turnover and increased risk for fracture. One of the proposed mechanisms is possible derangement in bone precursor cells, which could be represented by deficiencies in circulating osteogenic progenitor (COP) cells and osteoclast precursors (OCP). The objective of our study is to understand whether extent of glycemic control has an impact on these cells, and to identify other factors that may as well.

METHODS

This was a secondary analysis of baseline data from 51 male participants, aged 37-65 in an ongoing clinical trial at Michael E. DeBakey VA Medical Center, Houston, Texas, USA. At study entry serum Hemoglobin A1c was measured by high-performance liquid chromatography osteocalcin (OCN) and C-terminal telopeptide of type 1 collagen (CTx) were measured by ELISA, and testosterone and estradiol by liquid-chromatography/mass-spectrometry. Areal bone mineral density (BMD), trabecular bone score and body composition were measured by dual energy x-ray absorptiometry, while COP and OCP were measured by flow cytometry.

RESULTS

When adjusted for serum testosterone, parathyroid hormone, and 25-hydroxyvitamin D, those with poor long-term glycemic control had significantly higher percentage of COP (p = 0.04). COP correlated positively with visceral adipose tissue (VAT) volume (r = 0.37, p = 0.01) and negatively with free testosterone (r = -0.28, p = 0.05) and OCN (r = -0.28, p = 0.07), although only borderline for the latter. OCP correlated positively with age, FSH, lumbar spine BMD, and COP levels, and negatively with glucose, triglycerides, and free estradiol. Multivariable regression analyses revealed that, in addition to being predictors for each other, another independent predictor for COP was VAT volume while age, glucose, and vitamin D for OCP.

CONCLUSION

Our results suggest that high COP could be a marker of poor metabolic control. However, given the complex nature and the multitude of factors influencing osteoblastogenesis/adipogenesis, it is possible that the increase in COP is a physiologic response of the bone marrow to increased osteoblast apoptosis from poor glycemic control. Alternatively, it is also likely that a metabolically unhealthy profile may retard the development of osteogenic precursors to fully mature osteoblastic cells.

FSH and bone: Comparison between males with central versus primary hypogonadism

OBJECTIVE

Experimental studies proposed a direct effect of follicle-stimulating hormone (FSH) on the skeletal metabolism, but results of human studies mainly conducted in females are controversial. The present study aims to investigate the possible role of FSH excess in male bone health, by comparing for the first time primary and central hypogonadism.

DESIGN AND METHODS

119 men were enrolled in this cross-sectional observational study at the time of the first diagnosis of hypogonadism. All participants had spontaneous pubertal development. Regarding patients with hypergonadotropic hypogonadism (Hyper-H), Klinefelter syndrome (KS) patients were distinguished from the other forms (non-KS-Hyper-H) based on the onset of FSH elevation. Bone mineral density (BMD) at both lumbar spine (LS) and femoral neck (FN), as well as the prevalence of morphometric vertebral fractures (VFx), were assessed.

RESULTS

Across the whole cohort, higher LS and FN BMD were associated with older age at diagnosis and higher body mass index (BMI), respectively. After adjusting for potential confounders (age at diagnosis, BMI, smoking habits, degree of hypogonadism defined by calculated free testosterone, and 25OH vitamin D levels), non-KS-Hyper-H patients showed significantly lower LS BMD and tended to show lower FN BMD values, as compared to those with hypogonadotropic hypogonadism (Hypo-H). In KS men, LS BMD was significantly lower than in those with non-KS-Hyper-H. No significant differences in the prevalence of VFx were found between the groups.

CONCLUSIONS

These findings suggest a potential negative effect of FSH excess on the male bone mass, especially at spine. The duration of high FSH levels may also contribute to these findings.

Management of Osteoporosis in Men: A Narrative Review

Male osteoporosis is a still largely underdiagnosed pathological condition. As a consequence, bone fragility in men remains undertreated mainly due to the low screening frequency and to controversies in the bone mineral density (BMD) testing standards. Up to the 40% of overall osteoporotic fractures affect men, in spite of the fact that women have a significant higher prevalence of osteoporosis. In addition, in males, hip fractures are associated with increased morbidity and mortality as compared to women. Importantly, male fractures occur about 10 years later in life than women, and, therefore, due to the advanced age, men may have more comorbidities and, consequently, their mortality is about twice the rate in women. Gender differences, which begin during puberty, lead to wider bones in males as compared with females. In men, follicle-stimulating hormones, testosterone, estrogens, and sex hormone-binding levels, together with genetic factors, interact in determining the peak of bone mass, BMD maintenance, and lifetime decrease. As compared with women, men are more frequently affected by secondary osteoporosis. Therefore, in all osteoporotic men, a complete clinical history should be collected and a careful physical examination should be done, in order to find clues of a possible underlying diseases and, ultimately, to guide laboratory testing. Currently, the pharmacological therapy of male osteoporosis includes aminobisphosphonates, denosumab, and teriparatide. Hypogonadal patients may be treated with testosterone replacement therapy. Given that the fractures related to mortality are higher in men than in women, treating male subjects with osteoporosis is of the utmost importance in clinical practice, as it may impact on mortality even more than in women.

FSH Level and Changes in Bone Mass and Body Composition in Older Women and Men

CONTEXT

FSH may have independent actions on bone remodeling and body fat regulation. Cross-sectionally, we have shown that serum FSH is associated with bone mineral density (BMD) and body fat in older postmenopausal women, but it remains unknown whether FSH predicts bone and fat changes.

OBJECTIVE

We examined whether baseline FSH level is associated with subsequent bone loss or body composition changes in older adults.

SETTING, DESIGN, PARTICIPANTS

We studied 162 women and 158 men (mean age 82 ± 4 years) from the Age, Gene/Environment Susceptibility (AGES)-Bone Marrow Adiposity cohort, a substudy of the AGES-Reykjavik Study of community-dwelling older adults. Skeletal health and body composition were characterized at baseline and 3 years later.

MAIN OUTCOMES

Annualized change in BMD and body composition by dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT). Models were adjusted for serum estradiol and testosterone levels.

RESULTS

There was no evidence for an association between baseline FSH level and change in BMD or body composition by DXA or QCT. For femoral neck areal BMD, adjusted mean difference (95% CI) per SD increase in FSH was 1.3 (-0.7 to 3.3) mg/cm2/y in women, and -0.2 (-2.6 to 2.2) mg/cm2/y in men. For visceral fat, adjusted mean difference (95% CI) per SD increase in FSH was 1.80 (-0.03 to 3.62) cm2/y in women, and -0.33 (-3.73 to 3.06) cm2/y in men.

CONCLUSIONS

Although cross-sectional studies and studies in perimenopausal women have demonstrated associations between FSH and BMD and body composition, in older adults, FSH level is not associated with bone mass or body composition changes.

Actions and Roles of FSH in Germinative Cells

Follicle stimulating hormone (FSH) is produced by the pituitary gland in a coordinated hypothalamic-pituitary-gonadal (HPG) axis event, plays important roles in reproduction and germ cell development during different phases of reproductive development (fetal, neonatal, puberty, and adult life), and is consequently essential for fertility. FSH is a heterodimeric glycoprotein hormone of two dissociable subunits, α and β. The FSH β-subunit (FSHβ) function starts upon coupling to its specific receptor: follicle-stimulating hormone receptor (FSHR). FSHRs are localized mainly on the surface of target cells on the testis and ovary (granulosa and Sertoli cells) and have recently been found in testicular stem cells and extra-gonadal tissue. Several reproduction disorders are associated with absent or low FSH secretion, with mutation of the FSH β-subunit or the FSH receptor, and/or its signaling pathways. However, the influence of FSH on germ cells is still poorly understood; some studies have suggested that this hormone also plays a determinant role in the self-renewal of germinative cells and acts to increase undifferentiated spermatogonia proliferation. In addition, in vitro, together with other factors, it assists the process of differentiation of primordial germ cells (PGCLCs) into gametes (oocyte-like and SSCLCs). In this review, we describe relevant research on the influence of FSH on spermatogenesis and folliculogenesis, mainly in the germ cell of humans and other species. The possible roles of FSH in germ cell generation in vitro are also presented.

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.

The impact of leuprolide acetate-loaded calcium phosphate silicate cement to bone regeneration under osteoporotic conditions

Osteoporosis is detrimental to the health of skeletal structure and significantly increases the risks of bone fracture. Moreover, bone regeneration is adversely impaired by increased osteoclastic activities as a result of osteoporosis. In this study, we developed a novel formulation of injectable bone cement based on calcium phosphate silicate cement (CPSC) and leuprolide acetate (LA). Several combinations of LA-CPSC bone cement were characterized and, it is found that LA could increase the setting time and compressive strength of CPSC in a concentration-dependent manner. Moreover, thein vitroresults revealed that LA-CPSC was biocompatible and able to encourage the osteoblast proliferation via the mTOR signalling pathway. Furthermore, the LA-CPSC was implanted in the osteoporotic rats to evaluate its effectiveness to repair bone fractures under the osteoporotic conditions. The biomarker study and micro-CT analyses indicated that LA-CPSC could effectively reduce the osteoclast activities and promote the bone regeneration. In conclusion, our study demonstrated that LA-CPSC injectable bone cement should be a viable solution to repair bone fractures under the osteoporotic conditions.

Bone-to-Brain: A Round Trip in the Adaptation to Mechanical Stimuli

Besides the classical ones (support/protection, hematopoiesis, storage for calcium, and phosphate) multiple roles emerged for bone tissue, definitively making it an organ. Particularly, the endocrine function, and in more general terms, the capability to sense and integrate different stimuli and to send signals to other tissues, has highlighted the importance of bone in homeostasis. Bone is highly innervated and hosts all nervous system branches; bone cells are sensitive to most of neurotransmitters, neuropeptides, and neurohormones that directly affect their metabolic activity and sensitivity to mechanical stimuli. Indeed, bone is the principal mechanosensitive organ. Thanks to the mechanosensing resident cells, and particularly osteocytes, mechanical stimulation induces metabolic responses in bone forming (osteoblasts) and bone resorbing (osteoclasts) cells that allow the adaptation of the affected bony segment to the changing environment. Once stimulated, bone cells express and secrete, or liberate from the entrapping matrix, several mediators (osteokines) that induce responses on distant targets. Brain is a target of some of these mediator [e.g., osteocalcin, lipocalin2, sclerostin, Dickkopf-related protein 1 (Dkk1), and fibroblast growth factor 23], as most of them can cross the blood-brain barrier. For others, a role in brain has been hypothesized, but not yet demonstrated. As exercise effectively modifies the release and the circulating levels of these osteokines, it has been hypothesized that some of the beneficial effects of exercise on brain functions may be associated to such a bone-to-brain communication. This hypothesis hides an interesting clinical clue: may well-addressed physical activities support the treatment of neurodegenerative diseases, such as Alzheimer’s and Parkinson’s diseases?

Recent advances in understanding gonadotropin signaling

Gonadotropins are glycoprotein sex hormones regulating development and reproduction and bind to specific G protein–coupled receptors expressed in the gonads. Their effects on multiple signaling cascades and intracellular events have recently been characterized using novel technological and scientific tools. The impact of allosteric modulators on gonadotropin signaling, the role of sugars linked to the hormone backbone, the detection of endosomal compartments supporting signaling modules, and the dissection of different effects mediated by these molecules are areas that have advanced significantly in the last decade. The classic view providing the exclusive activation of the cAMP/protein kinase A (PKA) and the steroidogenic pathway by these hormones has been expanded with the addition of novel signaling cascades as determined by high-resolution imaging techniques. These new findings provided new potential therapeutic applications. Despite these improvements, unanswered issues of gonadotropin physiology, such as the intrinsic pro-apoptotic potential to these hormones, the existence of receptors assembled as heteromers, and their expression in extragonadal tissues, remain to be studied. Elucidating these issues is a challenge for future research.

Do polyunsaturated fatty acids protect against bone loss in our aging and osteoporotic population?

Age-related bone loss is inevitable in both men and women and there will soon be more people of extreme old age than ever before. Osteoporosis is a common chronic disease and as the proportion of older people, rate of obesity and the length of life increases, a rise in age-related degenerating bone diseases, disability, and prolonged dependency is projected. Fragility fractures are one of the most severe complications associated with both primary and secondary osteoporosis and current treatment strategies target weight-bearing exercise and pharmacological intervention, both with limited long-term success. Obesity and osteoporosis are intimately interrelated, and diet is a variable that plays a significant role in bone regeneration and repair. The Western Diet is characterized by its unhealthy components, specifically excess amounts of saturated fat intake. This review examines the impact of saturated and polyunsaturated fatty acid consumption on chronic inflammation, osteogenesis, bone architecture, and strength and explores the hypothesis that dietary polyunsaturated fats have a beneficial effect on osteogenesis, reducing bone loss by decreasing chronic inflammation, and activating bone resorption through key cellular and molecular mechanisms in our aging population. We conclude that aging, obesity and a diet high in saturated fatty acids significantly impairs bone regeneration and repair and that consumption of ω-3 polyunsaturated fatty acids is associated with significantly increased bone regeneration, improved microarchitecture and structural strength. However, ω-6 polyunsaturated fatty acids were typically pro-inflammatory and have been associated with an increased fracture risk. This review suggests a potential role for ω-3 fatty acids as a non-pharmacological dietary method of reducing bone loss in our aging population. We also conclude that contemporary amendments to the formal nutritional recommendations made by the Food and Nutrition Board may be necessary such that our aging population is directly considered.

Follicle stimulating hormone and estradiol alter immune response in osteoarthritic mice in an opposite manner

Although a number of studies have shown that the occurrence and progression of osteoarthritis (OA) is related to endocrine system dysfunction, there is limited evidence about what roles sex hormones play. The aim of the present study was to examine the capacity of 17β-estradiol (ED) and follicle stimulating hormone (FSH) to alter the differentiation of bone marrow (BM) cells in arthritic mice. The experiments were conducted in collagenase-induced osteoarthritis in mice. Cartilage degradation was observed by safranin and toluidine blue staining. Flow cytometry was used to define different BM and synovial cell populations. The influence of FSH and ED on osteoclastogenesis was studied in BM cultures and on the osteoblastogenesis in primary calvarial cultures. The levels of IL-8, TNF-α, FSH, and osteocalcin were estimated by ELISA. FSH increased cartilage degradation and serum osteocalcin levels, while ED abolished it and lowered serum osteocalcin. FSH elevated the percentage of monocytoid CD14+/RANK+ and B cell CD19+/RANK+ cells in contrast to ED which inhibited the accumulation of these osteogenic populations. Also, ED changed the percentage of CD105+/F4/80+ and CD11c+ cells in the synovium. FSH augmented and ED suppressed macrophage colony-stimulating factor (M-CSF) + receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast (OC) formation, and this correlated with a respective increase and decrease of IL-8 secretion. FSH did not influence osteoblast (OB) formation while ED enhanced this process in association with changes of TNF-α, IL-8, and osteocalcin production. ED reduced osteoclast generation in bone. The key outcome of the current study is that both hormones influenced BM cell differentiation, with FSH favoring osteoclast formation and ED favoring osteoblast accumulation.

A Novel Hypothesis: A Role for Follicle Stimulating Hormone in Abdominal Aortic Aneurysm Development in Postmenopausal Women

An abdominal aortic aneurysm (AAA) is a dilatation of the abdominal aorta, which can potentially be fatal due to exsanguination following rupture. Although AAA is less prevalent in women, women with AAA have a more severe AAA progression compared to men as reflected by enhanced aneurysm growth rates and a higher rupture risk. Women are diagnosed with AAA at an older age than men, and in line with increased osteoporosis and cardiovascular events, the delayed AAA onset has been attributed to the reduction of the protective effect of oestrogens during the menopausal transition. However, new insights have shown that a high follicle stimulating hormone (FSH) level during menopause may also play a key role in those diseases. In this report we hypothesize that FSH may aggravate AAA development and progression in postmenopausal women via a direct and/or indirect role, promoting aorta pathology. Since FSH receptors (FSHR) are reported on many other cell types than granulosa cells in the ovaries, it is feasible that FSH stimulation of FSHR-bearing cells such as aortic endothelial cells or inflammatory cells, could promote AAA formation directly. Indirectly, AAA progression may be influenced by an FSH-mediated increase in osteoporosis, which is associated with aortic calcification. Also, an FSH-mediated decrease in cholesterol uptake by the liver and an increase in cholesterol biosynthesis will increase the cholesterol level in the circulation, and subsequently promote aortic atherosclerosis and inflammation. Lastly, FSH-induced adipogenesis may lead to obesity-mediated dysfunction of the microvasculature of the aorta and/or modulation of the periaortic adipose tissue. Thus the long term increased plasma FSH levels during the menopausal transition may contribute to enhanced AAA disease in menopausal women and could be a potential novel target for treatment to lower AAA-related events in women.

Follicle-Stimulating Hormone Induces Lipid Droplets via Gαi/o and β-Arrestin in an Endometrial Cancer Cell Line

Follicle-stimulating hormone (FSH) and its G protein-coupled receptor, FSHR, represents a paradigm for receptor signaling systems that activate multiple and complex pathways. Classically, FSHR activates Gαs to increase intracellular levels of cAMP, but its ability to activate other G proteins, and β-arrestin-mediated signaling is well documented in many different cell systems. The pleiotropic signal capacity of FSHR offers a mechanism for how FSH drives multiple and dynamic downstream functions in both gonadal and non-gonadal cell types, including distinct diseases, and how signal bias may be achieved at a pharmacological and cell system-specific manner. In this study, we identify an additional mechanism of FSH-mediated signaling and downstream function in the endometrial adenocarcinoma Ishikawa cell line. While FSH did not induce increases in cAMP levels, this hormone potently activated pertussis toxin sensitive Gαi/o signaling. A selective allosteric FSHR ligand, B3, also activated Gαi/o signaling in these cells, supporting a role for receptor-mediated activation despite the low levels of FSHR mRNA. The low expression levels may attribute to the lack of Gαs/cAMP signaling as increasing FSHR expression resulted in FSH-mediated activation of the Gαs pathway. Unlike prior reports for FSH-mediated Gαs/cAMP signaling, FSH-mediated Gαi/o signaling was not affected by inhibition of dynamin-dependent receptor internalization. While chronic FSH did not alter cell viability, FSH was able to increase lipid droplet size. The β-arrestins are key adaptor proteins known to regulate FSHR signaling. Indeed, a rapid, FSH-dependent increase in interactions between β-arrestin1 and Gαi1 was observed via NanoBiT complementation in Ishikawa cells. Furthermore, both inhibition of Gαi/o signaling and siRNA knockdown of β-arrestin 1/2 significantly reduced FSH-induced lipid droplet accumulation, implying a role for a Gαi/o/β-arrestin complex in FSH functions in this cell type. As FSH/FSHR has been implicated in distinct hormone-dependent cancers, including endometrial cancer, analysis of the cancer genome database from 575 human endometrial adenocarcinoma tumors revealed that a subpopulation of samples expressed FSHR. Overall, this study highlights a novel mechanism for FSHR signal pleiotropy that may be exploited for future personalized therapeutic approaches.

Reduced Gonadotrophin Receptor Expression Is Associated with a More Aggressive Ovarian Cancer Phenotype

Follicle-stimulating hormone (FSH) and luteinising hormone (LH) play important roles in regulating cell growth and proliferation in the ovary. However, few studies have explored the expression of FSH and LH receptors (FSHR and LHCGR) in ovarian cancer, and their functional roles in cancer progression remain inconclusive. This study investigated the potential impact of both mRNA (FSHR, LHCGR) and protein (FSHR, LHCGR) expression on ovarian cancer progression using publicly available online databases, qRT-PCR (high grade serous ovarian cancers, HGSOC, n = 29 and benign ovarian tumors, n = 17) and immunohistochemistry (HGSOC, n = 144). In addition, we investigated the effect of FSHR and LHCGR siRNA knockdown on the pro-metastatic behavior of serous ovarian cancer cells in vitro. High FSHR or high LHCGR expression in patients with all subtypes of high-grade ovarian cancer was significantly associated with longer progression-free survival (PFS) and overall survival (OS). High FSHR protein expression was associated with increased PFS (p = 0.050) and OS (p = 0.025). HGSOC patients with both high FSHR and high LHCGR protein levels had the best survival outcome, whilst both low FSHR and low LHCGR expression was associated with poorest survival (p = 0.019). Knockdown of FSHR significantly increased the invasion of serous ovarian cancer cells (OVCAR3 and COV362) in vitro. LHCGR knockdown also promoted invasion of COV362 cells. This study highlights that lower FSHR and LHCGR expression is associated with a more aggressive epithelial ovarian cancer phenotype and promotes pro-metastatic behaviour.

FSH-R Human Early Male Genital Tract, Testicular Tumors and Sperm: Its Involvement in Testicular Disorders

The follicle-stimulating hormone receptor (FSH-R) expression was always considered human gonad-specific. The receptor has also been newly detected in extragonadal tissues. In this finding, we evaluated FSH-R expression in the human male early genital tract, in testicular tumors, and in sperm from healthy and varicocele patients. In sperm, we also studied the mechanism of FSH-R action. Immunohystochemistry and Western blot analysis showed FSH-R presence in the first pathways of the human genital tract, in embryonal carcinoma, and in sperm, but it was absent in seminoma and in lower varicocele. In sperm, FSH/FSH-R activity is mediated by G proteins activating the PKA pathway, as we observed by using the H89. It emerged that increasing FSH treatments induced motility, survival, capacitation, and acrosome reaction in both sperm samples. The different FSH-R expression in tumor testicular tissues may be discriminate by tumor histological type. In spermatozoa, FSH-R indicates a direct action of FSH in these cells, which could be beneficial during semen preparation for in vitro fertilization procedures. For instance, FSH positive effects could be relevant in idiopathic infertility and in the clinic surgery of varicocele. In conclusion, FSH-R expression may be considered a molecular marker of testicular disorders.

Zhuang-Gu-Fang Treats Osteoporosis in Ovariectomized Rats by Increasing the Osteogenesis-Related Factors Leptin, Ghrelin, and PYY

Zhuang-Gu-Fang is a Chinese medicinal compound mixture, which is mainly composed of traditional remedies like the Epimedium Herb, Astragalus, and Eucommia among many others. The study is aimed at investigating the therapeutic effect of Zhuang-Gu-Fang in ovariectomized rats. Fifty six-month-old Wistar rats were randomly selected and divided into 5 groups (n = 10), namely, model group, positive group, low-dose Chinese medicine group, medium-dose group, and high-dose group. Another 10 sham operation Wistar rats were taken as a negative control group. After 3 months of intervention, the bone mineral density (BMD), procollagen type I N-peptide (PINP), beta C-terminal cross-linked telopeptides of type I collagen carboxyl-terminal peptide (β-CTX), Leptin, Ghrelin, and Peptide YY (PYY) of each group were measured. Besides, the ultrastructure of bone structure and osteoblasts was also observed by transmission electron microscopy. Western blot method was used to detect the expression levels of Leptin and Ghrelin in bone tissue, and RT-PCR detected the mRNA expression levels of Leptin and Ghrelin. BMD test indicated that Zhuang-Gu-Fang could effectively prevent the loss of tibia bone in ovariectomized rats. Histomorphology analysis showed that Zhuang-Gu-Fang could preserve trabecular bone structure integrity and improve osteoblast ultrastructure. Notably, the study found out that Zhuang-Gu-Fang worked through balancing the bone metabolism via increasing bone formation/resorption ratio. Additionally, Zhuang-Gu-Fang highlighted the recovery effects in multiple levels of osteogenesis- and osteanagenesis-related factors Leptin, Ghrelin, and PYY. Conclusively, the study proved the therapeutic potential of the Zhuang-Gu-Fang for postmenopausal osteoporosis (PMOP) and further revealed that its therapeutic effect was related to the balance of bone metabolism and the recovery effects of bone-related factors Leptin, Ghrelin, and PYY.

Beyond bone biology: Lessons from team science

Today, research in biomedicine often requires the knowledge and technologies in diverse fields. Therefore, there is an increasing need for collaborative team science that crosses traditional disciplines. Here, we discuss our own lessons from both interdisciplinary and transdisciplinary teams, which ultimately ushered us to expand our research realm beyond bone biology.

First-in-class humanized FSH blocking antibody targets bone and fat

Blocking the action of FSH genetically or pharmacologically in mice reduces body fat, lowers serum cholesterol, and increases bone mass, making an anti-FSH agent a potential therapeutic for three global epidemics: obesity, osteoporosis, and hypercholesterolemia. Here, we report the generation, structure, and function of a first-in-class, fully humanized, epitope-specific FSH blocking antibody with a K _D of 7 nM. Protein thermal shift, molecular dynamics, and fine mapping of the FSH-FSH receptor interface confirm stable binding of the Fab domain to two of five receptor-interacting residues of the FSHβ subunit, which is sufficient to block its interaction with the FSH receptor. In doing so, the humanized antibody profoundly inhibited FSH action in cell-based assays, a prelude to further preclinical and clinical testing.

Inhibition of Adipogenic Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells by a Phytoestrogen Diarylheptanoid from Curcuma comosa

We investigated the effect of a phytoestrogen, (3R)-1,7-diphenyl-(4E,6E)-4,6-heptadien-3-ol (DPHD), from Curcuma comosa Roxb. (Zingiberaceae family) on the adipogenic differentiation of mesenchymal progenitors, human bone marrow-derived mesenchymal stem cells (hBMSCs). DPHD inhibited adipocyte differentiation of hBMSCs by suppressing the expression of genes involved in adipogenesis. DPHD at concentrations of 0.1, 1, and 10 μM significantly decreased triglyceride accumulation in hBMSCs to 7.1 ± 0.2, 6.3 ± 0.4, and 4.9 ± 0.2 mg/dL, respectively, compared to the nontreated control (10.1 ± 0.9 mg/dL) (p < 0.01). Based on gene expression profiling, DPHD increased the expression of several genes involved in the Wnt/β-catenin signaling pathway, a negative regulator of adipocyte differentiation in hBMSCs. DPHD also increased the levels of essential signaling proteins which are extracellular signal-regulated kinases 1 and 2 (ERK1/2) and glycogen synthase kinase 3 beta (GSK-3β) that link estrogen receptor (ER) signaling to Wnt/β-catenin signaling. In conclusion, DPHD exhibited the anti-adipogenic effect in hBMSCs by suppression of adipogenic markers in hBMSCs through the activation of ER and Wnt/β catenin signaling pathways. This finding suggests the potential role of DPHD in preventing bone marrow adiposity which is one of the major factors that exacerbates osteoporosis in postmenopause.

Follicle-stimulating hormone and estradiol are associated with bone mineral density and risk of fractures in men with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is associated with a higher fracture risk. Sex hormones are important for maintaining skeletal health. It is not clear which sex hormone(s) contribute(s) to bone mineral density (BMD) and fracture risk in males with T2DM. This study investigated the relationships of these parameters in males with T2DM.

METHODS

This study involved 482 men with T2DM. BMDs at the lumbar spine (L2-4), femoral neck (FN), and total hip (TH) were measured by dual-energy X-ray absorptiometry (DXA). The 10-year probability of fractures was assessed using the modified Fracture Risk Algorithm (FRAX) tool. Serum levels of sex hormones were measured.

RESULTS

Follicle-stimulating hormone (FSH) and estradiol (E2) were associated with BMDs at L2-4 (FSH, β = -.162, P < .05; E2, β = .176, P < .001), and E2 was associated with BMD at FN (β = .137, P < .05) and TH (β = .140, P < .05). FSH was associated with major osteoporotic fractures (β = .288, P < .001) and hip fractures (β = .235, P < .001). Higher FSH was a risk factor for osteoporosis/osteopenia (odds ratios [OR] = 2.92, 95% CI = 1.66-5.14, P < .001), whereas higher E2 was a protective factor (OR = 0.37, 95% CI = 0.22-0.60, P < .001). Patients in the higher tertile of FSH and lower tertile of E2 had an increased risk of osteoporosis/osteopenia (OR = 5.05, 95% CI = 1.37-18.65, P < .05).

CONCLUSIONS

For males with T2DM, FSH and E2 are significantly associated with BMD, osteoporosis/osteopenia, and fracture risk.

In-depth characterization of monocyte subsets during the course of healthy pregnancy

Pregnancy represents an immunological challenge for the maternal immune system. Pregnancy augments innate immune responses, and particularly monocytes contribute to maintaining the balance between pro- and anti-inflammatory immune responses required for the successful sequence of distinct immunological phases throughout pregnancy. Nonetheless, studies that focus on the heterogeneity of monocytes and analyze the alteration of monocyte subsets in a longitudinal approach throughout healthy pregnancies have remained scarce. In this study, we characterized the gradual phenotypic changes of monocyte subsets and the secretory potential of bulk monocytes in peripheral blood mononuclear cells of healthy pregnant women from a population-based prospective birth cohort study. Blood samples at predefined time points were analyzed using flow cytometry for in-depth characterization of monocyte subsets, which confirmed a shift from classical towards intermediate monocytes throughout pregnancy. Principal component analysis revealed characteristic phenotypic changes on monocyte subsets, especially on the intermediate monocyte subset, throughout pregnancy. Pregnancy-related hormones were measured in serum and β-human chorionic gonadotropin levels were significantly associated with expression of CD11b, CD116 and CCR2 on monocyte subsets. TLR4 and TLR7/8 stimulation of monocytes furthermore showed reduced polycytokine production towards the end of pregnancy. These data provide a comprehensive overview of phenotypic changes and secretory potential of monocytes in healthy pregnant women and establish a selective contribution of different monocyte subsets to healthy pregnancy. The results from this study therefore build a basis for future comparisons and evaluation of women with adverse pregnancy outcomes.

Heat shock protein 90 alpha and 14-3-3η in postmenopausal osteoporotic rats with varying levels of serum FSH

PURPOSE

This study compared the severity of osteoporosis and screened differentially expressed proteins in postmenopausal osteoporotic rats with varying levels of serum follicle stimulating hormone (FSH).

METHODS

Thirty-six Sprague Dawley female rats were divided into four groups: sham operation (sham) group, ovariectomy (OVX) group, FSH and ovariectomy (OVX + FSH) group, and Leuprorelin (LE) and ovariectomy group (OVX + LE). Body weight, serum estradiol, FSH, tartrate-resistant acid phosphatase, alkaline phosphatase, and bone mineral density were measured. We randomly selected six rats each from the OVX and OVX + FSH groups to detect differentially expressed proteins by data-independent acquisition, and we verified the results in the remaining six rats by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Nineteen proteins were upregulated and 36 proteins were downregulated in the OVX + FSH group. The expression of heat shock protein 90 alpha (Hsp90α) and 14-3-3η protein was significantly different between the OVX and OVX + FSH groups, and both were linearly correlated with bone trabecular area. Results were verified by ELISA and were found to be consistent with the results of data-independent acquisition.

DISCUSSION

In rats with high serum FSH, expression of Hsp90α protein was increased and expression of 14-3-3η protein was decreased. Both changes in protein expression were strongly correlated with bone trabecular area.

FSH-metabolic circuitry and menopause

FSH has a primary function in procreation, wherein it induces estrogen production in females and regulates spermatogenesis in males. However, in line with our discoveries over the past decade of non-unitary functions of pituitary hormones, we and others have described hitherto uncharacterized functions of FSH. Through high-affinity receptors, some of which are variants of the ovarian FSH receptor (FSHR), FSH regulates bone mass, adipose tissue function, energy metabolism, and cholesterol production in both sexes. These newly described actions of FSH may indeed be relevant to the pathogenesis of bone loss, dysregulated energy homeostasis, and disordered lipid metabolism that accompany the menopause in females and aging in both genders. We are therefore excited about the possibility of modulating circulating FSH levels toward a therapeutic benefit for a host of age-associated diseases, including osteoporosis, obesity and dyslipidemia, among other future possibilities.

Gonadotropins and their receptors: coevolution, genetic variants, receptor imaging, and functional antagonists

Gonadotropins belong to the family of dimeric glycoprotein hormones and regulate gonadal physiology mediated by G protein-coupled, seven-transmembrane receptors. These glycoprotein hormones are widely used in the clinic to promote ovarian follicle development and for treating some cases of male infertility. We traced the coevolution of dimeric gonadotropin hormones and their receptors, together with thyrotropin and its receptor. We updated recent findings on human genetic variants of these genes and their association with dizygotic twining, polycystic ovarian syndrome, primary ovarian insufficiency, male-limited precocious puberty, and infertility. In addition to the known physiological roles of gonadotropin-receptor signaling in gonadal tissues, we also discussed emerging understanding of extragonadal functions of gonadotropins in bones and adipose tissues, together with recent advances in in vivo imaging of gonadotropin receptors in live animals. Recent development of gonadotropin receptor agonists and antagonists were summarized with an emphasis on the development of functional antagonists for FSH receptors to alleviate osteoporosis and obesity associated with menopause.

FSH Beyond Fertility

The traditional view of follicle-stimulating hormone (FSH) as a reproductive hormone is changing. It has been shown that FSH receptors (FSHRs) are expressed in various extra-gonadal tissues and mediate the biological effects of FSH at those sites. Molecular, animal, epidemiologic, and clinical data suggest that elevated serum FSH may play a significant role in the evolution of bone loss and obesity, as well as contributing to cardiovascular and cancer risk. This review summarizes recent data on FSH action beyond reproduction.

Extragonadal FSHR Expression and Function-Is It Real?

Expression of the follicle-stimulating hormone receptor (FSHR), besides gonadal tissues, has recently been detected in several extragonadal normal and tumorous tissues, including different types of primary and metastatic cancer and tumor vessel endothelial cells (TVEC). The suggested FSH actions in extragonadal tissues include promotion of angiogenesis, myometrial contractility, skeletal integrity, and adipose tissue accumulation. Non-malignant cells within cancer tissue have been shown to be devoid of FSHR expression, which implies a potential role of FSHR as a diagnostic, prognostic, or even a therapeutic tool. There are shared issues between several of the published reports questioning the validity of some of the conclusion. Firstly, protein expression of FSHR was performed solely with immunohistochemistry (IHC) using either an unavailable "in house" FSHR323 monoclonal antibody or poorly validated polyclonal antibodies, usually without additional methodological quality control and confirmations. Secondly, there is discrepancy between the hardly traceable or absent FSHR gene amplification/transcript data and non-reciprocal strong FSHR protein immunoreactivity. Thirdly, the pharmacological high doses of recombinant FSH used in in vitro studies also jeopardizes the physiological or pathophysiological meaning of the findings. We performed in this review a critical analysis of the results presenting extragonadal expression of FSHR and FSH action, and provide a rationale for the validation of the reported results using additional more accurate and sensitive supplemental methods, including in vivo models and proper positive and negative controls.

FSH Actions and Pregnancy: Looking Beyond Ovarian FSH Receptors

By mediating estrogen synthesis and follicular growth in response to FSH, the ovarian FSH receptor (FSHR) is essential for female fertility. Indeed, ovarian stimulation via administration of FSH to women with infertility is part of the primary therapeutic intervention used in assisted reproductive technology. In physiological and therapeutic contexts, current dogma dictates that once ovulation has occurred, FSH/FSHR signaling is no longer required for successful pregnancy outcomes. However, a continued role for FSH during pregnancy is suggested by recent studies demonstrating extraovarian FSHR in the female reproductive tract. Furthermore, functional roles for FSHR in placenta and in uterine myometrium have now been demonstrated. In placenta, vascular endothelial FSHR of fetal vessels within the chorionic villi (human) or labyrinth (mouse) mediate angiogenesis, and it has further been shown that deletion of placental Fshr in mice has deleterious effects on pregnancy. In uterine myometrium, changes in the densities of FSHR in muscle fiber and stroma in the nonpregnant state, early pregnancy, and term pregnancy differentially regulate contractile activity, suggesting that signaling through myometrial FSHR may contribute to the quieting of contractile activity required for successful implantation and that the temporal upregulation of the FSHR at term pregnancy may be required for the appropriate timing of parturition. In addition, extraovarian expression of mRNAs encoding the glycoprotein hormone α subunit and the FSH β subunit has been demonstrated, suggesting that these novel aspects of extraovarian FSH/FSHR signaling during pregnancy may be mediated by locally synthesized FSH.

Deletion of fetoplacental Fshr inhibits fetal vessel angiogenesis in the mouse placenta

It has been shown in both human and mouse placentas that follicle stimulating hormone receptor (FSHR) is expressed in fetal vascular endothelium. There are conflicting reports, however, on the role of FSH to stimulate angiogenesis in vitro in cultured endothelial cells from umbilical veins. Therefore, in this study we undertook an in vivo approach utilizing Fshr null mice to definitively address this question. In the context where all pregnant dams have identical Fshr genotypes, we generated fetuses and associated fetal portions of placenta that were Fshr wt or Fshr null and analyzed angiogenesis within the placental labyrinths. Quantitative morphometric analyses of placentas obtained at mid-gestation revealed that the percentage of the placenta composed of labyrinth is significantly decreased in Fshr null placentas relative to wt placentas. Furthermore, data presented demonstrate that within the Fshr null labyrinths, fetal vessel angiogenesis was significantly reduced relative to wt labyrinths. The results obtained with this combination of in vivo and genetic approaches conclusively demonstrate that signaling through endothelial FSHR does indeed stimulate angiogenesis and that placental Fshr is essential for normal angiogenesis of the fetal placental vasculature.