KLF15 Is a transcriptional regulator of the human 17beta-hydroxysteroid dehydrogenase type 5 gene. A potential link between regulation of testosterone production and fat stores in women

Pubertal Girls With Overweight/Obesity Have Higher Androgen Levels-Can Metabolomics Tell us Why?

CONTEXT

Pubertal girls with higher total body fat (TBF) demonstrate higher androgen levels. The cause of this association is unknown but is hypothesized to relate to insulin resistance.

OBJECTIVE

This work aimed to investigate the association between higher TBF and higher androgens in pubertal girls using untargeted metabolomics.

METHODS

Serum androgens were determined using a quantitative mass spectrometry (MS)-based assay. Metabolomic samples were analyzed using liquid chromatography high-resolution MS. Associations between TBF or body mass index (BMI) z score (exposure) and metabolomic features (outcome) and between metabolomic features (exposure) and serum hormones (outcome) were examined using gaussian generalized estimating equation models with the outcome lagged by one study visit. Benjamini-Hochberg false discovery rate (FDR) adjusted P values were calculated to account for multiple testing. RaMP-DB (relational database of metabolomic pathways) was used to conduct enriched pathway analyses among features nominally associated with body composition or hormones.

RESULTS

Sixty-six pubertal, premenarchal girls (aged 10.9 ± 1.39 SD years; 60% White, 24% Black, 16% other; 63% normal weight, 37% overweight/obese) contributed an average of 2.29 blood samples. BMI and TBF were negatively associated with most features including raffinose (a plant trisaccharide) and several bile acids. For BMI, RaMP-DB identified many enriched pathways related to bile acids. Androstenedione also showed strong negative associations with raffinose and bile acids.

CONCLUSION

Metabolomic analyses of samples from pubertal girls did not identify an insulin resistance signature to explain the association between higher TBF and androgens. Instead, we identified potential novel signaling pathways that may involve raffinose or bile acid action at the adrenal gland.

Obesity-Related Hypogonadism in Women

Obesity-related hypogonadotropic hypogonadism is a well-characterized condition in men (termed male obesity-related secondary hypogonadism; MOSH); however, an equivalent condition has not been as clearly described in women. The prevalence of polycystic ovary syndrome (PCOS) is known to increase with obesity, but PCOS is more typically characterized by increased gonadotropin-releasing hormone (GnRH) (and by proxy luteinizing hormone; LH) pulsatility, rather than by the reduced gonadotropin levels observed in MOSH. Notably, LH levels and LH pulse amplitude are reduced with obesity, both in women with and without PCOS, suggesting that an obesity-related secondary hypogonadism may also exist in women akin to MOSH in men. Herein, we examine the evidence for the existence of a putative non-PCOS "female obesity-related secondary hypogonadism" (FOSH). We précis possible underlying mechanisms for the occurrence of hypogonadism in this context and consider how such mechanisms differ from MOSH in men, and from PCOS in women without obesity. In this review, we consider relevant etiological factors that are altered in obesity and that could impact on GnRH pulsatility to ascertain whether they could contribute to obesity-related secondary hypogonadism including: anti-Müllerian hormone, androgen, insulin, fatty acid, adiponectin, and leptin. More precise phenotyping of hypogonadism in women with obesity could provide further validation for non-PCOS FOSH and preface the ability to define/investigate such a condition.

The Roles of Autophagy in the Genesis and Development of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common and frequent disease and always leads endocrine and metabolic disorder among women in reproductive age. Ovary is the main organ involved in polycystic ovary syndrome, and its function impairment will lead to reproductive dysfunction. Some recent studies have demonstrated that autophagy plays an important role in the pathogenesis of PCOS, and there are many different mechanisms that affect autophagy and the occurrence of PCOS, and they provide a new direction for us to predict the mechanism of PCOS. In this review, we discuss the role of autophagy in different ovarian cells: granulosa cells, oocytes, and theca cells, and introduce the important role that they play in the progress of PCOS. The main purpose of this review is to provide the research background and some relevant suggestions for our future work in autophagy and help us better explore the pathogenesis and autophagy mechanisms of PCOS. Furthermore, it will help us gain a new insight of the pathophysiology and treatment of PCOS.

17β-hydroxysteroid dehydrogenases in the progression of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has become a worldwide epidemic and a major public health problem, with a prevalence of approximately 25%. The pathogenesis of NAFLD is complex and may be affected by the environment and susceptible genetic factors, resulting in a highly variable disease course and no approved drugs in the clinic. Notably, 17β-hydroxysteroid dehydrogenase type 13 (HSD17B13), which belongs to the 17β-hydroxysteroid dehydrogenase superfamily (HSD17Bs), is closely related to the clinical outcome of liver disease. HSD17Bs consists of fifteen members, most related to steroid and lipid metabolism, and may have the same biological function as HSD17B13. In this review, we highlight recent advances in basic research on the functional activities, major substrates, and key roles of HSD17Bs in the progression of NAFLD to develop innovative anti-NAFLD drugs targeting HSD17Bs.

The circadian rhythm regulates branched-chain amino acids metabolism in fast muscle of Chinese perch (Siniperca chuatsi) during short-term fasting by Clock-KLF15-Bcat2 pathway

As an internal time-keeping mechanism, circadian rhythm plays crucial role in maintaining homoeostasis when in response to nutrition change; meanwhile, branched-chain amino acids (BCAA) in skeletal muscle play an important role in preserving energy homoeostasis during fasting. Previous results from our laboratory suggested that fasting can influence peripheral circadian rhythm and BCAA metabolism in fish, but the relationship between circadian rhythm and BCAA metabolism, and whether circadian rhythm regulates BCAA metabolism to maintain physiological homoeostasis during fasting remains unclear. This study shows that the expression of fifteen core clock genes as well as KLF15 and Bcat2 is highly responsive to short-term fasting in fast muscle of Siniperca chuatsi, and the correlation coefficient between Clock and KLF15 expression is enhanced after fasting treatment. Furthermore, we demonstrate that the transcriptional expression of KLF15 is regulated by Clock, and the transcriptional expression of Bcat2 is regulated by KLF15 by using dual-luciferase reporter gene assay and Vivo-morpholinos-mediated gene knockdown technique. Therefore, fasting imposes a dynamic coordination of transcription between the circadian rhythm and BCAA metabolic pathways. The findings highlight the interaction between circadian rhythm and BCAA metabolism and suggest that fasting induces a switch in KLF15 expression through affecting the rhythmic expression of Clock, and then KLF15 promotes the transcription of Bcat2 to enhance the metabolism of BCAA, thus maintaining energy homoeostasis and providing energy for skeletal muscle as well as other tissues.

The Interplay between Finasteride-Induced Androgen Imbalance, Endoplasmic Reticulum Stress, Oxidative Stress, and Liver Disorders in Paternal and Filial Generation

Finasteride (Fin) causes androgen imbalance by inhibiting the conversion of testosterone (T) to its more active metabolite, dihydrotestosterone (DHT). Androgen receptors (AR) are present (e.g., in hepatocytes), which have well-developed endoplasmic reticulum (ERet). Cellular protein quality control is carried out by ERet in two paths: (i) unfolded protein response (UPR) and/or (ii) endoplasmic reticulum associated degradation (ERAD). ERet under continuous stress can generate changes in the UPR and can direct the cell on the pathway of life or death. It has been demonstrated that genes involved in ERet stress are among the genes controlled by androgens in some tissues. Oxidative stress is also one of the factors affecting the functions of ERet and androgens are one of the regulators of antioxidant enzyme activity. In this paper, we discuss/analyze a possible relationship between androgen imbalance in paternal generation with ERet stress and liver disorders in both paternal and filial generation. In our rat model, hyperglycemia and subsequent higher accumulation of hepatic glycogen were observed in all filial generation obtained from females fertilized by Fin-treated males (F1:Fin). Importantly, genes encoding enzymes involved in glucose and glycogen metabolism have been previously recognized among UPR targets.

Hyper-androgenemia and obesity in early-pubertal girls

PURPOSE

The aim of this study was to examine the hormonal profile in early-pubertal girls with obesity. We hypothesized that these patients might already present hormonal alterations with POCS-like features.

METHODS

Cross-sectional study in a sample of 283 peri-pubertal girls (prepubertal and early-puberty subgroups), aged 6.1-12.0 years, diagnosed with obesity (BMI-SDS > 2.0, 97th percentile), so-called obesity group. They all underwent clinical examination and blood testing for hormonal measurements (leptin, TSH, FT4, IGF-1, IGFBP3, prolactin, insulin, FSH, LH, estradiol, ACTH, cortisol, 17-OH-P, DHE-S, androstenedione, testosterone and free testosterone). A control group was recruited: 243 healthy girls, aged 6.3-12.1 years, with normal BMI status.

RESULTS

Prepubertal girls with obesity had significantly higher values (p < 0.05) for BMI-SDS, leptin, insulin and HOMA-IR levels than control group. Early-pubertal girls with obesity also had significantly higher values (p < 0.05) for BMI-SDS, leptin, IGF-1, IGFBP3, insulin and HOMA-IR, LH, ratio LH/FSH, ACTH, DHE-S, androstenedione, testosterone and free testosterone levels than control group. In early-pubertal girls with obesity (not prepubertal girls), there was a positive correlation (p < 0.01) between leptin levels with LH, androstenedione and testosterone, and HOMA-IR with LH and testosterone levels. There was also a positive correlation (p < 0.01) between IGF-1 levels with LH, androstenedione, DHE-S and testosterone; and LH levels with testosterone.

CONCLUSION

The results obtained support our hypothesis that an abnormal hormonal profile with POCS-like features can already be detected (insulin resistance and hyperinsulinemia, increased secretion of LH and ACTH, and overproduction of ovarian and adrenal androgens) in early-pubertal girls with obesity.

HaloChIP-seq for Antibody-Independent Mapping of Mouse Transcription Factor Cistromes in vivo

Chromatin immunoprecipitation (ChIP) maps, on a genome-wide scale, transcription factor binding sites, and the distribution of other chromatin-associated proteins and their modifications. As such, it provides valuable insights into mechanisms of gene regulation. However, successful ChIP experiments are dependent on the availability of a high-quality antibody against the target of interest. Using antibodies with poor sensitivity and specificity can yield misleading results. This can be partly circumvented by using epitope-tagged systems ( e.g. , HA, Myc, His), but these approaches are still antibody-dependent. HaloTag ® is a modified dehalogenase enzyme, which covalently binds synthetic ligands. This system can be used for imaging and purification of HaloTag ® fusion proteins, and has been used for ChIP in vitro . Here, we present a protocol for using the HaloTag ® system for ChIP in vivo , to map, with sensitivity and specificity, the cistrome of a dynamic mouse transcription factor expressed at its endogenous locus. Graphical abstract.

Polycystic ovary syndrome: Identification of novel and hub biomarkers in the autophagy-associated mRNA-miRNA-lncRNA network

INTRODUCTION

Polycystic ovary syndrome (PCOS) is a common metabolic and endocrine disorder prevalent among women of reproductive age. Recent studies show that autophagy participated in the pathogenesis of PCOS, including anovulation, hyperandrogenism, and metabolic disturbances. This study was designed to screen autophagy-related genes (ATGs) that may play a pivotal role in PCOS, providing potential biomarkers and identifying new molecular subgroups for therapeutic intervention.

METHODS

Gene expression profiles of the PCOS and control samples were obtained from the publicly available Gene Expression Omnibus database. The gene lists of ATGs from databases were integrated. Then, the weighted gene co-expression network analysis was conducted to obtain functional modules and construct a multifactorial co-expression network. Gene Ontology and KEGG pathway enrichment analyses were performed for further exploration of ATG's function in the key modules. Differentially expressed ATGs were identified and validated in external datasets with the Limma R package. To provide guidance on PCOS phenotyping, the dysfunction module consists of a co-expression network mapped to PCOS patients. A PCOS-Autophagy-related co-expression network was established using Cytoscape, followed by identifying molecular subgroups using the Limma R package. ps. RNA-sequencing analysis was used to confirm the differential expression of hub ATGs, and the diagnostic value of hub ATGs was assessed by receiver operating characteristic curve analysis.

RESULTS

Three modules (Brown, Turquoise, and Green) in GSE8157, three modules (Blue, Red, and Green) in GSE43264, and four modules (Blue, Green, Black, and Yellow) in GSE106724 were identified to be PCOS-related by WGCNA analysis. 29 ATGs were found to be the hub genes that strongly correlated with PCOS. These hub ATGs were mainly enriched in autophagy-related functions and pathways such as autophagy, endocytosis, apoptosis, and mTOR signaling pathways. The mRNA-miRNA-lncRNA multifactorial network was successfully constructed. And three new molecular subgroups were identified via the K-means algorithm.

DISCUSSION

We provide a novel insight into the mechanisms behind autophagy in PCOS. BRCA1, LDLR, MAP1B, hsa-miR-92b-3p, hsa-miR-20b-5p, and NEAT1 might play a considerably important role in PCOS dysfunction. As a result, new potential biomarkers can be evaluated for use in PCOS diagnosis and treatment in the future.

FoxO-KLF15 pathway switches the flow of macronutrients under the control of insulin

KLF15 is a transcription factor that plays an important role in the activation of gluconeogenesis from amino acids as well as the suppression of lipogenesis from glucose. Here we identified the transcription start site of liver-specific KLF15 transcript and showed that FoxO1/3 transcriptionally regulates Klf15 gene expression by directly binding to the liver-specific Klf15 promoter. To achieve this, we performed a precise in vivo promoter analysis combined with the genome-wide transcription-factor-screening method "TFEL scan", using our original Transcription Factor Expression Library (TFEL), which covers nearly all the transcription factors in the mouse genome. Hepatic Klf15 expression is significantly increased via FoxOs by attenuating insulin signaling. Furthermore, FoxOs elevate the expression levels of amino acid catabolic enzymes and suppress SREBP-1c via KLF15, resulting in accelerated amino acid breakdown and suppressed lipogenesis during fasting. Thus, the FoxO-KLF15 pathway contributes to switching the macronutrient flow in the liver under the control of insulin.

PA and OA induce abnormal glucose metabolism by inhibiting KLF15 in adipocytes

Background

Obesity-induced elevated serum free fatty acids (FFAs) levels result in the occurrence of type 2 diabetes mellitus (T2DM). However, the molecular mechanism remains largely enigmatic. This study was to explore the effect and mechanism of KLF15 on FFAs-induced abnormal glucose metabolism.

Methods

Levels of TG, TC, HDL-C, LDL-C, and glucose were measured by different assay kits. qRT-PCR and Western Blot were used to detect the levels of GPR120, GPR40, phosphorylation of p38 MAPK, KLF15, and downstream factors.

Results

KLF15 was decreased in visceral adipose tissue of obesity subjects and high-fat diet (HFD) mice. In HFD mice, GPR120 antagonist significantly promoted KLF15 protein expression level and phosphorylation of p38 MAPK, meanwhile reduced the blood glucose levels. While, blocking GPR40 inhibited the KLF15 expression. In 3T3-L1 adipocytes, 1500 μM PA inhibited KLF15 through a GPR120/P-p38 MAPK signal pathway, and 750 μM OA inhibited KLF15 mainly through GPR120 while not dependent on P-p38 MAPK, ultimately resulting in abnormal glucose metabolism. Unfortunately, GPR40 didn’t contribute to PA or OA-induced KLF15 reduction.

Conclusions

Both PA and OA inhibit KLF15 expression through GPR120, leading to abnormal glucose metabolism in adipocytes. Notably, the inhibition of KLF15 expression by PA depends on phosphorylation of p38 MAPK.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12986-021-00628-2.

Normal and Premature Adrenarche

Adrenarche is the maturational increase in adrenal androgen production that normally begins in early childhood. It results from changes in the secretory response to adrenocorticotropin (ACTH) that are best indexed by dehydroepiandrosterone sulfate (DHEAS) rise. These changes are related to the development of the zona reticularis (ZR) and its unique gene/enzyme expression pattern of low 3ß-hydroxysteroid dehydrogenase type 2 with high cytochrome b5A, sulfotransferase 2A1, and 17ß-hydroxysteroid dehydrogenase type 5. Recently 11-ketotestosterone was identified as an important bioactive adrenarchal androgen. Birth weight, body growth, obesity, and prolactin are related to ZR development. Adrenarchal androgens normally contribute to the onset of sexual pubic hair (pubarche) and sebaceous and apocrine gland development. Premature adrenarche causes ≥90% of premature pubarche (PP). Its cause is unknown. Affected children have a significantly increased growth rate with proportionate bone age advancement that typically does not compromise growth potential. Serum DHEAS and testosterone levels increase to levels normal for early female puberty. It is associated with mildly increased risks for obesity, insulin resistance, and possibly mood disorder and polycystic ovary syndrome. Between 5% and 10% of PP is due to virilizing disorders, which are usually characterized by more rapid advancement of pubarche and compromise of adult height potential than premature adrenarche. Most cases are due to nonclassic congenital adrenal hyperplasia. Algorithms are presented for the differential diagnosis of PP. This review highlights recent advances in molecular genetic and developmental biologic understanding of ZR development and insights into adrenarche emanating from mass spectrometric steroid assays.

Autophagy in ovary and polycystic ovary syndrome: role, dispute and future perspective

Polycystic ovary syndrome (PCOS) is a unification of endocrine and metabolic disorders and has become immensely prevalent among women of fertile age. The prime organ affected in PCOS is the ovary and its distressed functioning elicits disturbed reproductive outcomes. In the ovary, macroautophagy/autophagy performs a pivotal role in directing the chain of events starting from oocytes origin until its fertilization. Recent discoveries demonstrate a significant role of autophagy in the pathogenesis of PCOS. Defective autophagy in the follicular cells during different stages of follicles is observed in the PCOS ovary. Exploring different autophagy pathways provides a platform for predicting the possible cause of altered ovarian physiology in PCOS. In this review, we have emphasized autophagy's role in governing follicular development under normal circumstances and in PCOS, including significant abnormalities associated with PCOS such as anovulation, hyperandrogenemia, metabolic disturbances, and related abnormality. So far, few studies have linked autophagy and PCOS and propose its essential role in PCOS progression. However, detailed knowledge in this area is lacking. Here we have summarized the latest knowledge related to autophagy associated with PCOS. This review's main objective is to provide a background of autophagy in the ovary, its possible connection with PCOS and suggested a novel proposal for future studies to aid a better understanding of PCOS pathogenesis.Abbreviations: AE: androgen excess; AF: antral follicle; AKT/PKB: AKT serine/threonine kinase; AMH: anti-Mullerian hormone; AMPK: AMP-activated protein kinase; ATG: autophagy-related; BCL2: BCL2 apoptosis regulator; BECN1: beclin 1; BMP: bone morphogenetic protein; CASP3: caspase 3; CL: corpus luteum; CYP17A1/P450C17: cytochrome P450 family 17 subfamily A member 1; CYP19A1: cytochrome P450 family 19 subfamily A member 1; DHEA: dehydroepiandrosterone; EH: endometrial hyperplasia; FF: follicular fluid; FOXO: forkhead box O; FSH: follicle stimulating hormone; GC: granulosa cell; GDF: growth differentiation factor; HA: hyperandrogenemia; HMGB1: high mobility group box 1; IGF1: insulin like growth factor 1; INS: insulin; IR: insulin resistance; LHCGR/LHR: luteinizing hormone/choriogonadotropin receptor; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MAPK/ERK: mitogen-activated protein kinase; MAPK8/JNK: mitogen-activated protein kinase 8; MTOR: mechanistic target of rapamycin kinase; MTORC: mechanistic target of rapamycin complex; NAFLD: nonalcoholic fatty liver disease; NFKB: nuclear factor kappa B; OLR1/LOX-1: oxidized low density lipoprotein receptor 1; oxLDL: oxidized low-density lipoproteins; PA: palmitic acid; PCOS: polycystic ovary syndrome; PF: primary follicle; PGC: primordial germ cell; PI3K: phosphoinositide 3-kinase; PMF: primordial follicle; ROS: reactive oxygen species; RP: resting pool; SIRT1: sirtuin 1; SQSTM1/p62: sequestosome 1; T2DM: type 2 diabetes mellitus; TC: theca cell; TUG1: taurine up-regulated 1.

Characterization With Gene Mutations in Han Chinese Patients With Hypospadias and Function Analysis of a Novel AR Genevariant

It is estimated that around 10-20% of hypospadias are caused by genetic abnormalities worldwide although the spectrum of associated genes does vary across different ethnicities. The prevalence of hypospadias among the Chinese population has been increasing the last couple of decades. However, the pathogenesis underlying the disease and its associated genetic abnormality remains unclear. Here we performed a genetic analysis of 81 children with karyotype 46, XY and the hypospadias phenotype in order to characterize the genetic components that contribute to the development of hypospadias in Chinese patients. 15 candidate genes, including sex determination genes-SOX9, SRY, NR0B1 (DAX1), NR5A1 (SF1), DHH, sex differentiation genes-AR, SRD5A2, MAMLD1, INSL3, and hypospadias-associated genes-FGF8, FGF10, BMP4, BMP7, ATF3, and MID1 were screened by using next generation sequencing. A total of 18 patients were found to have mutations identified by PCR and sequencing, including 11 cases of SRD5A2 genes, 6 cases of AR genes, and 1 case of MID1 gene, respectively. One novel missense mutation p.I817N was discovered in AR gene. Further molecular analysis found that subcellular localization of the AR_{I 81 7N} was the same as that of wild type AR_WT in the absence or presence of hormone. But it led to 50% reduction in AR-induced transcriptional activity in the presence of either the synthetic androgen R1881 or the natural ligand dihydrotestosterone. Our results indicate that SRD5A2 and AR genes are two top candidate genes associated with 46, XY hypospadias in Chinese patients. Further epidemiological and genetic analysis are still needed to further clarify the pathogenesis of hypospadias in Han Chinese patients.

Regulation of Krüppel-Like Factor 15 Expression by Herpes Simplex Virus Type 1 or Bovine Herpesvirus 1 Productive Infection

Expression of Krüppel-like factor 15 (KLF15), a stress-induced transcription factor, is induced during bovine herpesvirus 1 (BoHV-1) reactivation from latency, and KLF15 stimulates BoHV-1 replication. Transient transfection studies revealed that KLF15 and glucocorticoid receptor (GR) cooperatively transactivate the BoHV-1-immediate-early transcription unit 1 (IEtu1), herpes simplex virus type 1 (HSV-1) infected cell protein 0 (ICP0), and ICP4 promoters. The IEtu1 promoter drives expression of bICP0 and bICP4, two key BoHV-1 transcriptional regulatory proteins. Based on these studies, we hypothesized infection is a stressful stimulus that increases KLF15 expression and enhances productive infection. New studies demonstrated that silencing KLF15 impaired HSV-1 productive infection, and KLF15 steady-state protein levels were increased at late stages of productive infection. KLF15 was primarily localized to the nucleus following infection of cultured cells with HSV-1, but not BoHV-1. When cells were transfected with a KLF15 promoter construct and then infected with HSV-1, promoter activity was significantly increased. The ICP0 gene, and to a lesser extent, bICP0 transactivated the KLF15 promoter in the absence of other viral proteins. In contrast, BoHV-1 or HSV-1 encoded VP16 had no effect on KLF15 promoter activity. Collectively, these studies revealed that HSV-1 and BoHV-1 productive infection increased KLF15 steady-state protein levels, which correlated with increased virus production.

Longitudinal Investigation of Pubertal Milestones and Hormones as a Function of Body Fat in Girls

CONTEXT

Epidemiologic studies have demonstrated that overweight/obese girls (OW/OB) undergo thelarche and menarche earlier than normal weight girls (NW). There have been no longitudinal studies to specifically investigate how body weight/fat affects both clinical and biochemical pubertal markers in girls.

OBJECTIVE

To investigate the effect of total body fat on reproductive hormones and on the maturation of estrogen-sensitive tissues during puberty in girls.

METHODS

Ninety girls (36 OW/OB, 54 NW), aged 8.2 to 14.7 years, completed 2.8 ± 1.7 study visits over 4 years. Visits included dual-energy x-ray absorptiometry to calculate total body fat (TBF), Tanner staging, breast ultrasound for morphological staging (BMORPH; A-E), pelvic ultrasound, hormone tests, and assessment of menarchal status. The effect of TBF on pubertal markers was determined using a mixed, multistate, or Cox proportional hazards model, controlling for baseline BMORPH.

RESULTS

NW were older than OW/OB (11.3 vs 10.2 years, P < .01) at baseline and had more advanced BMORPH (P < .01). Luteinizing hormone, estradiol, and ovarian and uterine volumes increased with time with no effect of TBF. There was a time × TBF interaction for follicle-stimulating hormone, inhibin B, estrone, total and free testosterone, and androstenedione: Levels were initially similar, but after 1 year, levels increased in girls with higher TBF, plateaued in girls with midrange TBF, and decreased in girls with lower TBF. Girls with higher TBF progressed through BMORPH stage D more slowly but achieved menarche earlier than girls with lower TBF.

CONCLUSION

In late puberty, girls with higher TBF demonstrate differences in standard hormonal and clinical markers of puberty. Investigation of the underlying causes and clinical consequences of these differences in girls with higher TBF deserves further study.

EWS-FLI1 regulates and cooperates with core regulatory circuitry in Ewing sarcoma

Core regulatory circuitry (CRC)-dependent transcriptional network is critical for developmental tumors in children and adolescents carrying few gene mutations. However, whether and how CRC contributes to transcription regulation in Ewing sarcoma is unknown. Here, we identify and functionally validate a CRC 'trio' constituted by three transcription factors (TFs): KLF15, TCF4 and NKX2-2, in Ewing sarcoma cells. Epigenomic analyses demonstrate that EWS-FLI1, the primary fusion driver for this cancer, directly establishes super-enhancers of each of these three TFs to activate their transcription. In turn, KLF15, TCF4 and NKX2-2 co-bind to their own and each other's super-enhancers and promoters, forming an inter-connected auto-regulatory loop. Functionally, CRC factors contribute significantly to cell proliferation of Ewing sarcoma both in vitro and in vivo. Mechanistically, CRC factors exhibit prominent capacity of co-regulating the epigenome in cooperation with EWS-FLI1, occupying 77.2% of promoters and 55.6% of enhancers genome-wide. Downstream, CRC TFs coordinately regulate gene expression networks in Ewing sarcoma, controlling important signaling pathways for cancer, such as lipid metabolism pathway, PI3K/AKT and MAPK signaling pathways. Together, molecular characterization of the oncogenic CRC model advances our understanding of the biology of Ewing sarcoma. Moreover, CRC-downstream genes and signaling pathways may contain potential therapeutic targets for this malignancy.

Current concepts of polycystic ovary syndrome pathogenesis

PURPOSE OF REVIEW

This review provides a model for understanding polycystic ovary syndrome (PCOS) pathophysiology and updates the evidence on which it is based. Then, it highlights complimentary molecular genetic and epigenetic advances in understanding PCOS cause.

RECENT FINDINGS

Important studies into PCOS cause built on the 2014 discovery of a novel regulatory protein variant that underlies the typical PCOS steroidogenic abnormalities: DENND1A.V2 (differentially expressed in normal and neoplastic development, isoform 1A, variant 2). Over 30 DENND1A gene variants have been found, the vast majority upstream of the coding sequence and potentially regulatory. These variants are individually uncommon but collectively plausibly cause 50% of PCOS. Anti-Müllerian hormone (AMH)/AMH receptor variants with decreased function possibly cause 6.7% of PCOS. DENNND1A was recently reported to belong to a signaling network that upregulates luteinizing hormone receptor expression and insulin mitogenic signaling. Prenatal androgen administration has proven to be a potent epigenetic regulator that causes transgenerational epigenomic changes in a mouse PCOS model with similarities to those in human PCOS and PCOS daughters.

SUMMARY

In addition to finding how gene variants contribute to PCOS pathogenesis, better understanding of androgen epigenetic mechanisms of action in diverse tissues can be expected to expand our understanding of PCOS pathogenesis.

The Glucocorticoid Receptor (GR) Stimulates Herpes Simplex Virus 1 Productive Infection, in Part Because the Infected Cell Protein 0 (ICP0) Promoter Is Cooperatively Transactivated by the GR and Krüppel-Like Transcription Factor 15

Following acute infection, herpes simplex virus 1 (HSV-1) establishes lifelong latency in neurons. Physical, emotional, and chemical stresses are linked to increasing the incidence of reactivation from latency, but the mechanism of action is not well understood. In general, stress increases corticosteroid levels, leading to activation of the glucocorticoid receptor (GR), a pioneer transcription factor. Consequently, we hypothesized that stress-mediated activation of the GR can stimulate productive infection and viral gene expression. New studies demonstrated that the GR-specific antagonist (CORT-108297) significantly reduced HSV-1 productive infection in mouse neuroblastoma cells (Neuro-2A). Additional studies demonstrated that the activated GR and Krüppel-like transcription factor 15 (KLF15) cooperatively transactivated the infected cell protein 0 (ICP0) promoter, a crucial viral regulatory protein. Interestingly, the synthetic corticosteroid dexamethasone and GR or KLF15 alone had little effect on ICP0 promoter activity in transfected Neuro-2A or Vero cells. Chromatin immunoprecipitation (ChIP) studies revealed that the GR and KLF15 occupied ICP0 promoter sequences important for transactivation at 2 and 4 h after infection; however, binding was not readily detected at 6 h after infection. Similar results were obtained for cells transfected with the full-length ICP0 promoter. ICP0 promoter sequences lack a consensus "whole" GR response element (GRE) but contain putative half-GREs that were important for dexamethasone induced promoter activity. The activated GR stimulates expression of, and interacts with, KLF15; consequently, these data suggest KLF15 and the GR form a feed-forward loop that activates viral gene expression and productive infection following stressful stimuli.IMPORTANCE The ability of herpes simplex virus 1 (HSV-1) to periodically reactivate from latency results in virus transmission and recurrent disease. The incidence of reactivation from latency is increased by chronic or acute stress. Stress increases the levels of corticosteroids, which bind and activate the glucocorticoid receptor (GR). Since GR activation is an immediate early response to stress, we tested whether the GR influences productive infection and the promoter that drives infected cell protein 0 (ICP0) expression. Pretreatment of cells with a GR-specific antagonist (CORT-108297) significantly reduced virus replication. Although the GR had little effect on ICP0 promoter activity alone, the Krüppel-like transcription factor 15 (KLF15) cooperated with the GR to stimulate promoter activity in transfected cells. In transfected or infected cells, the GR and KLF15 occupied ICP0 sequences important for transactivation. Collectively, these studies provide insight into how stress can directly stimulate productive infection and viral gene expression.

Developmental Dioxin Exposure Alters the Methylome of Adult Male Zebrafish Gonads

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a persistent environmental toxicant and endocrine disrupting compound with reproductive and developmental effects in humans and model organisms, including zebrafish. Our previous microarray and histological studies found defects in spermatogenesis and fertility of zebrafish in response to acute developmental TCDD exposure. These effects are apparent following exposure during reproductive development, modeling fetal basis of adult-onset disease. Some outcomes of these previous studies (reduced fertility, changes in sex ratio, transcriptomic alterations) are also transgenerational – persisting to unexposed generations – through the male germline. We hypothesized that DNA methylation could be a possible mechanism for these reproductive effects and performed whole genome bisulfite sequencing (WGBS), which identifies whole genome DNA methylation status at the base pair level, on testes of adult zebrafish exposed to TCDD (two separate hour-long exposures to 50 pg/mL TCDD at 3 and 7 weeks post fertilization). In response to TCDD exposure, multiple genes were differentially methylated; many of which are involved in reproductive processes or epigenetic modifications, suggesting a role of DNA methylation in later-life health outcomes. Additionally, several differentially methylated genes corresponded with gene expression changes identified in TCDD-exposed zebrafish testes, indicating a potential link between DNA methylation and gene expression. Ingenuity pathway analysis of WGBS and microarray data revealed genes involved in reproductive processes and development, RNA regulation, the cell cycle, and cellular morphology and development. We conclude that site-specific changes in DNA methylation of adult zebrafish testes occur in response to acute developmental TCDD exposure.

Synergistic Activation of Bovine Herpesvirus 1 Productive Infection and Viral Regulatory Promoters by the Progesterone Receptor and Krüppel-Like Transcription Factor 15

Bovine herpesvirus 1 (BoHV-1), including modified live vaccines, readily infects the fetus and ovaries, which can lead to reproductive failure. The BoHV-1 latency reactivation cycle in sensory neurons may further complicate reproductive failure in pregnant cows. The immediate early transcription unit 1 (IEtu1) promoter drives expression of important viral transcriptional regulators (bICP0 and bICP4). This promoter contains two functional glucocorticoid receptor (GR) response elements (GREs) that have the potential to stimulate productive infection following stressful stimuli. Since progesterone and the progesterone receptor (PR) can activate many GREs, we hypothesized that the PR and/or progesterone regulates productive infection and viral transcription. New studies demonstrated that progesterone stimulated productive infection. Additional studies revealed the PR and Krüppel-like transcription factor 15 (KLF15) cooperated to stimulate productive infection and IEtu1 promoter activity. IEtu1 promoter activation required both GREs, which correlated with the ability of the PR to interact with wild-type (wt) GREs but not mutant GREs. KLF15 also cooperated with the PR to transactivate the bICP0 early promoter, a promoter that maintains bICP0 protein expression during productive infection. Intergenic viral DNA fragments (less than 400 bp) containing two GREs and putative KLF binding sites present within genes encoding unique long 52 (UL-52; component of DNA primase/helicase complex), Circ, bICP4, and IEtu2 were stimulated by KLF15 and the PR more than 10-fold, suggesting that additional viral promoters are activated by these transcription factors. Collectively, these studies suggest progesterone and the PR promote BoHV-1 spread to reproductive tissues, thus increasing the incidence of reproductive failure.IMPORTANCE Bovine herpesvirus 1 (BoHV-1) is the most frequently diagnosed cause of abortions in pregnant cows and can cause "abortion storms" in susceptible herds. Virulent field strains and even commercially available modified live vaccines can induce abortion, in part because BoHV-1 replicates efficiently in the ovary and corpus luteum. We now demonstrate that progesterone and the progesterone receptor (PR) stimulate productive infection. The BoHV-1 genome contains approximately 100 glucocorticoid receptor (GR) response elements (GREs). Interestingly, the PR can bind and activate many promoters that contain GREs. The PR and Krüppel-like transcription factor 15 (KLF15), which regulate key steps during embryo implantation, cooperate to stimulate productive infection and two viral promoters that drive expression of key viral transcriptional regulators. These studies suggest that the ability of progesterone and the PR to stimulate productive infection has the potential to promote virus spread in reproductive tissue and induce reproductive failure.

Combinatorial Effects of the Glucocorticoid Receptor and Krüppel-Like Transcription Factor 15 on Bovine Herpesvirus 1 Transcription and Productive Infection

Bovine herpesvirus 1 (BoHV-1), an important bovine pathogen, establishes lifelong latency in sensory neurons. Latently infected calves consistently reactivate from latency following a single intravenous injection of the synthetic corticosteroid dexamethasone. The immediate early transcription unit 1 (IEtu1) promoter, which drives bovine ICP0 (bICP0) and bICP4 expression, is stimulated by dexamethasone because it contains two glucocorticoid receptor (GR) response elements (GREs). Several Krüppel-like transcription factors (KLF), including KLF15, are induced during reactivation from latency, and they stimulate certain viral promoters and productive infection. In this study, we demonstrate that the GR and KLF15 were frequently expressed in the same trigeminal ganglion (TG) neuron during reactivation and cooperatively stimulated productive infection and IEtu1 GREs in mouse neuroblastoma cells (Neuro-2A). We further hypothesized that additional regions in the BoHV-1 genome are transactivated by the GR or stress-induced transcription factors. To test this hypothesis, BoHV-1 DNA fragments (less than 400 bp) containing potential GR and KLF binding sites were identified and examined for transcriptional activation by stress-induced transcription factors. Intergenic regions within the unique long 52 gene (UL52; a component of the DNA primase/helicase complex), bICP4, IEtu2, and the unique short region were stimulated by KLF15 and the GR. Chromatin immunoprecipitation studies revealed that the GR and KLF15 interacted with sequences within IEtu1 GREs and the UL52 fragment. Coimmunoprecipitation studies demonstrated that KLF15 and the GR were associated with each other in transfected cells. Since the GR stimulates KLF15 expression, we suggest that these two transcription factors form a feed-forward loop that stimulates viral gene expression and productive infection following stressful stimuli.IMPORTANCE Bovine herpesvirus 1 (BoHV-1) is an important viral pathogen that causes respiratory disease and suppresses immune responses in cattle; consequently, life-threatening bacterial pneumonia can occur. Following acute infection, BoHV-1 establishes lifelong latency in sensory neurons. Reactivation from latency is initiated by the synthetic corticosteroid dexamethasone. Dexamethasone stimulates lytic cycle viral gene expression in sensory neurons of calves latently infected with BoHV-1, culminating in virus shedding and transmission. Two stress-induced cellular transcription factors, Krüppel-like transcription factor 15 (KLF15) and the glucocorticoid receptor (GR), cooperate to stimulate productive infection and viral transcription. Additional studies demonstrated that KLF15 and the GR form a stable complex and that these stress-induced transcription factors bind to viral DNA sequences, which correlates with transcriptional activation. The ability of the GR and KLF15 to synergistically stimulate viral gene expression and productive infection may be critical for the ability of BoHV-1 to reactivate from latency following stressful stimuli.

AKR1C3-Mediated Adipose Androgen Generation Drives Lipotoxicity in Women With Polycystic Ovary Syndrome

CONTEXT

Polycystic ovary syndrome (PCOS) is a prevalent metabolic disorder occurring in up to 10% of women of reproductive age. PCOS is associated with insulin resistance and cardiovascular risk. Androgen excess is a defining feature of PCOS and has been suggested as causally associated with insulin resistance; however, mechanistic evidence linking both is lacking. We hypothesized that adipose tissue is an important site linking androgen activation and metabolic dysfunction in PCOS.

METHODS

We performed a human deep metabolic in vivo phenotyping study examining the systemic and intra-adipose effects of acute and chronic androgen exposure in 10 PCOS women, in comparison with 10 body mass index-matched healthy controls, complemented by in vitro experiments.

RESULTS

PCOS women had increased intra-adipose concentrations of testosterone (P = 0.0006) and dihydrotestosterone (P = 0.01), with increased expression of the androgen-activating enzyme aldo-ketoreductase type 1 C3 (AKR1C3) (P = 0.04) in subcutaneous adipose tissue. Adipose glycerol levels in subcutaneous adipose tissue microdialysate supported in vivo suppression of lipolysis after acute androgen exposure in PCOS (P = 0.04). Mirroring this, nontargeted serum metabolomics revealed prolipogenic effects of androgens in PCOS women only. In vitro studies showed that insulin increased adipose AKR1C3 expression and activity, whereas androgen exposure increased adipocyte de novo lipid synthesis. Pharmacologic AKR1C3 inhibition in vitro decreased de novo lipogenesis.

CONCLUSIONS

These findings define an intra-adipose mechanism of androgen activation that contributes to adipose remodeling and a systemic lipotoxic metabolome, with intra-adipose androgens driving lipid accumulation and insulin resistance in PCOS. AKR1C3 represents a promising therapeutic target in PCOS.

Polycystic Ovary Syndrome Presents Higher Sympathetic Cardiac Autonomic Modulation that is not altered by Strength Training

Polycystic ovary syndrome (PCOS) may present important comorbidities, such as cardiovascular and metabolic diseases, which are often preceded by changes in cardiac autonomic modulation. Different types of physical exercises are frequently indicated for the prevention and treatment of PCOS. However, little is known about the effects of strength training on the metabolic, hormonal, and cardiac autonomic parameters. Therefore, our aim was to investigate the effects of strength training on the autonomic modulation of heart rate variability (HRV) and its relation to endocrine-metabolic parameters in women with PCOS. Fifty-three women were divided into two groups: CONTROL (n=26) and PCOS (n=27). The strength training lasted 4 months, which was divided into mesocycles of 4 weeks each. The training load started with 70% of one repetition maximum (1RM). Blood samples were collected before and after intervention for analysis of fasting insulin and glucose, HOMA-IR, testosterone, androstenedione and testosterone/androstenedione (T/A) ratio. Spectral analysis of HRV was performed to assess cardiac autonomic modulation indexes. The PCOS group presented higher insulin and testosterone levels, T/A ratio, along with increased sympathetic cardiac autonomic modulation before intervention. The training protocol used did not cause any change of endocrine-metabolic parameters in the CONTROL group. Interestingly, in the PCOS group, reduced testosterone levels and T/A ratio. Additionally, strength training did not have an effect on the spectral parameter values of HRV obtained in both groups. Strength training was not able to alter HRV autonomic modulation in women with PCOS, however may reduce testosterone levels and T/A ratio.

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.

Correlation of A2bAR and KLF4/KLF15 with Obesity-Dyslipidemia Induced Inflammation in Uygur Population

In this paper, the researchers collected visceral adipose tissue from the Uygur population, which were divided into two groups: the normal control group (NC, n = 50, 18.0 kg/m(2) ≤ BMI ≤ 23.9 kg/m(2)) and the obese group (OB, n = 45, BMI ≥ 28 kg/m(2)), and then use real-time PCR to detect the mRNA expression level of key genes involved in inflammation signaling pathway. The findings suggest that, in obese status, the lower expression level of A2bAR, KLF4, and KLF15 of visceral adipose tissue may correlate with obese-dyslipidemia induced inflammation in Uygur population.

Tanshinol Rescues the Impaired Bone Formation Elicited by Glucocorticoid Involved in KLF15 Pathway

Decreased bone formation is responsible for the pathogenesis of glucocorticoid- (GC-) induced osteoporosis (GIO), while the mechanism remains to be elucidated. The aim was to investigate how natural antioxidant tanshinol attenuates oxidative stress and rescues impaired bone formation elicited by GC in Sprague-Dawley rats and in C2C12 cells and/or MC3T3-E1 cells. The results showed that tanshinol prevented bone loss and decreased biomechanical characteristics and suppressed reduction of biomarkers related to osteogenesis in GIO rats. Further study revealed that tanshinol reversed decrease of transcription activity of Osterix-luc and rescued impairment of osteoblastic differentiation and bone formation involved in induction of KLF15 mRNA. Meanwhile, tanshinol diminished inhibition of protein expression of β-catenin and Tcf4 and transcription activity of Tcf4-luc induced by GC, especially under conditions of KLF siRNA in vitro. Additionally, tanshinol attenuated increase of reactive oxygen species (ROS) generation, phosphorylation of p66^Shc expression, TUNEL-positive cells, and caspase-3 activity elicited by KLF15 under conditions of GC. Taken together, the present findings suggest that tanshinol attenuated the decrease of bone formation and bone mass and bone quality elicited by GC involved in KLF15/Wnt signaling transduction and counteracted GC-evoked oxidative stress and subsequent cell apoptosis involved in KLF15/p66^Shc pathway cascade.

Adrenal androgens and androgen precursors-definition, synthesis, regulation and physiologic actions

The human adrenal produces more 19 carbon (C19) steroids, by mass, than either glucocorticoids or mineralocorticoids. However, the mechanisms regulating adrenal C19 steroid biosynthesis continue to represent one of the most intriguing mysteries of endocrine physiology. This review will discuss the C19 steroids synthesized by the human adrenal and the features within the adrenal that allow production of these steroids. Finally, we consider the effects of these steroids in normal physiology and disorders of adrenal C19 steroid excess.

Clinical review: Adolescent anovulation: maturational mechanisms and implications

CONTEXT

Adolescents are at high risk for menstrual dysfunction. The diagnosis of anovulatory disorders that may have long-term health consequences is too often delayed.

EVIDENCE ACQUISITION

A review of the literature in English was conducted, and data were summarized and integrated from the author's perspective.

MAIN FINDINGS

Normal adolescent anovulation causes only minor menstrual cycle irregularity: most cycles range from 21-45 days, even in the first postmenarcheal year, 90% by the fourth year. Approximately half of symptomatic menstrual irregularity is due to neuroendocrine immaturity, and half is associated with increased androgen levels. The former is manifest as aluteal or short/deficient luteal phase cycles and usually resolves spontaneously. The latter seems related to polycystic ovary syndrome because adolescent androgen levels are associated with adult androgens and ovulatory dysfunction, but data are sparse. Obesity causes hyperandrogenemia and, via unclear mechanisms, seems to suppress LH; it may mimic polycystic ovary syndrome. The role of pubertal insulin resistance in physiological adolescent anovulation is unclear. High-sensitivity gonadotropin and steroid assays, the latter by specialty laboratories, are necessary for accurate diagnosis of pubertal disorders. Polycystic ovaries are a normal ultrasonographic finding in young women and are associated with nearly 2-fold increased anti-Müllerian hormone levels. Oral contraceptives are generally the first-line treatment for ongoing menstrual dysfunction, and the effects of treatment are similar among preparations.

CONCLUSIONS

Menstrual cycle duration persistently outside 21-45 days in adolescents is unusual, and persistence ≥ 1 year suggests that disordered hypothalamic-pituitary-gonadal function be considered. Research is needed on the mechanisms and prognosis of adolescent anovulation.

Second cistron in CACNA1A gene encodes a transcription factor mediating cerebellar development and SCA6

The CACNA1A gene, encoding the voltage-gated calcium channel subunit α1A, is involved in pre- and postsynaptic Ca(2+) signaling, gene expression, and several genetic neurological disorders. We found that CACNA1A coordinates gene expression using a bicistronic mRNA bearing a cryptic internal ribosomal entry site (IRES). The first cistron encodes the well-characterized α1A subunit. The second expresses a transcription factor, α1ACT, which coordinates expression of a program of genes involved in neural and Purkinje cell development. α1ACT also contains the polyglutamine (polyQ) tract that, when expanded, causes spinocerebellar ataxia type 6 (SCA6). When expressed as an independent polypeptide, α1ACT-bearing an expanded polyQ tract-lacks transcription factor function and neurite outgrowth properties, causes cell death in culture, and leads to ataxia and cerebellar atrophy in transgenic mice. Suppression of CACNA1A IRES function in SCA6 may be a potential therapeutic strategy.

The influence of obesity on androstenedione to testosterone ratio in women with polycystic ovary syndrome (PCOS) and hyperandrogenemia

The aim of the present study was to evaluate the impact of obesity and insulin resistance on testosterone formation from androstenedione and its contribution to biochemical hyperandrogenemia in all different phenotypic subgroups of PCOS patients. The case-control study included 1087 PCOS women and 206 regularly menstruating, ovulatory controls. The main clinical measurements included anthropometric and basal hormonal characteristics and evaluation of hyperandrogenic and insulin resistance-related features. The results were the following: In PCOS women with biochemical hyperandrogenemia, obesity significantly lowers serum A levels and increases T to A ratio. These findings were not present in PCOS women with clinical hypeandrogenemia and in normal ovulatory controls.

Determination of the source of androgen excess in functionally atypical polycystic ovary syndrome by a short dexamethasone androgen-suppression test and a low-dose ACTH test

BACKGROUND

Polycystic ovary syndrome (PCOS) patients typically have 17-hydroxyprogesterone (17OHP) hyperresponsiveness to GnRH agonist (GnRHa) (PCOS-T). The objective of this study was to determine the source of androgen excess in the one-third of PCOS patients who atypically lack this type of ovarian dysfunction (PCOS-A).

METHODS

Aged-matched PCOS-T (n= 40), PCOS-A (n= 20) and controls (n= 39) were studied prospectively in a General Clinical Research Center. Short (4 h) and long (4-7 day) dexamethasone androgen-suppression tests (SDAST and LDAST, respectively) were compared in subsets of subjects. Responses to SDAST and low-dose adrenocorticotropic hormone (ACTH) were then evaluated in all.

RESULTS

Testosterone post-SDAST correlated significantly with testosterone post-LDAST and 17OHP post-GnRHa (r = 0.671-0.672), indicating that all detect related aspects of ovarian dysfunction. An elevated dehydroepiandrosterone peak in response to ACTH, which defined functional adrenal hyperandrogenism, was similarly prevalent in PCOS-T (27.5%) and PCOS-A (30%) and correlated significantly with baseline dehydroepiandrosterone sulfate (DHEAS) (r = 0.708). Functional ovarian hyperandrogenism was detected by subnormal testosterone suppression by SDAST in most (92.5%) PCOS-T, but significantly fewer PCOS-A (60%, P< 0.01). Glucose intolerance was absent in PCOS-A, but present in 30% of PCOS-T (P < 0.001). Most of the PCOS-A cases with normal testosterone suppression in response to SDAST (5/8) lacked evidence of adrenal hyperandrogenism and were obese.

CONCLUSIONS

Functional ovarian hyperandrogenism was not demonstrable by SDAST in 40% of PCOS-A. Most of these cases had no evidence of adrenal hyperandrogenism. Obesity may account for most hyperandrogenemic anovulation that lacks a glandular source of excess androgen, and the SDAST seems useful in making this distinction.

Mutations of the hexose-6-phosphate dehydrogenase gene rarely cause hyperandrogenemic polycystic ovary syndrome

BACKGROUND/AIM

Hexose-6-phosphate dehydrogenase (H6PD) inactivating mutations cause cortisone reductase deficiency, which manifests with hyperandrogenism unexplained by commonly used tests and, thus, mimics polycystic ovary syndrome (PCOS). The aim of this study was to screen for mutations of H6PD gene in PCOS patients with biochemical hyperandrogenemia.

METHODS

Direct DNA sequencing of the entire H6PD coding sequence was performed in 74 PCOS patients and 31 healthy controls. Results were confirmed by PCR-restriction fragment length polymorphism assay to determine the genotypic frequency of the variants.

RESULTS

Multiple novel missense variants were detected in the study. Two exon 2 variants (acccaggc deletion proximal to the start codon and D151A) and two exon 5 variants (R453Q and P554L) were common, occurring in 23.8%, 17.1%, 35.2%, and 16.1%, respectively. There was significant linkage disequilibrium between the exon 2 and exon 5 variants. No significant differences were observed in the genotype, allele distributions, or adrenal function tests of the variants between cases and control groups. We did not detect any reported inactivating mutations in our study.

CONCLUSION

Although the H6PD gene is very polymorphic and missense variants are common, coding variants rarely (<1.5%) are responsible for hyperandrogenemic PCOS. We suggest that genetic studies be reserved for patients with dexamethasone-suppressible adrenal hyperandrogenism who have a discrepancy between urinary 17α-hydroxycorticoid and cortisol excretion.

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.

Sp1 and KLF15 regulate basal transcription of the human LRP5 gene

Background

LRP5, a member of the low density lipoprotein receptor superfamily, regulates diverse developmental processes in embryogenesis and maintains physiological homeostasis in adult organisms. However, how the expression of human LRP5 gene is regulated remains unclear.

Results

In order to characterize the transcriptional regulation of human LRP5 gene, we cloned the 5' flanking region and evaluated its transcriptional activity in a luciferase reporter system. We demonstrated that both KLF15 and Sp1 binding sites between -72 bp and -53 bp contribute to the transcriptional activation of human LRP5 promoter. Chromatin immunoprecipitation assay demonstrated that the ubiquitous transcription factors KLF15 and Sp1 bind to this region. Using Drosophila SL2 cells, we showed that KLF15 and Sp1 trans-activated the LRP5 promoter in a manner dependent on the presence of Sp1-binding and KLF15-binding motifs.

Conclusions

Both KLF15 and Sp1 binding sites contribute to the basal activity of human LRP5 promoter. This study provides the first insight into the mechanisms by which transcription of human LRP5 gene is regulated.

Multimodal regulation of E2F1 gene expression by progestins

An analysis of mRNA expression in T47D breast cancer cells treated with the synthetic progestin R5020 revealed a subset of progesterone receptor (PR) target genes that are enriched for E2F binding sites. Following up on this observation, we determined that PR-B acts in both direct and indirect manners to positively upregulate E2F1 expression in T47D cells. The direct effects of PR on E2F1 expression were confirmed by chromatin immunoprecipitation (ChIP) analysis, which indicated that the agonist-bound receptor was recruited to several enhancer elements proximal to the E2F1 transcript. However, we also noted that cycloheximide partially inhibits R5020 induction of E2F1 expression, indicating that the ligand-dependent actions of PR on this gene may involve additional indirect regulatory pathways. In support of this hypothesis, we demonstrated that treatment with R5020 significantly increases both hyperphosphorylation of Rb and recruitment of E2F1 to its own promoter, thus activating a positive feedback loop that further amplifies its transcription. Furthermore, we established that PR-mediated induction of Krüppel-like factor 15 (KLF15), which can bind to GC-rich DNA within the E2F1 promoter, is required for maximal induction of E2F1 expression by progestins. Taken together, these results suggest a new paradigm for multimodal regulation of target gene expression by PR.

Adipose tissue expandability and the early origins of PCOS

The most prevalent phenotypes of polycystic ovary syndrome (PCOS) are characterized by insulin resistance and androgen excess. The adipose tissue (AT) expandability hypothesis explains the development of insulin resistance in obesity and in cases of AT deficit. In line with this hypothesis, we propose that hyperinsulinemic androgen excess in PCOS is often underpinned by exhaustion of the capacity to expand subcutaneous AT in a metabolically safe way. Such exhaustion might occur when a positive energy imbalance meets a normal fat-storage capacity and/or when a normal energy balance faces a low fat storage capacity. This concept thus explains how PCOS phenotypes might result from obesity, prenatal growth restraint or a genetic lipodystrophy, or, experimentally, from prenatal androgen excess.