Tissue control of androgen action: The ups and downs of androgen receptor expression

AR loss in prostate cancer stroma mediated by NF-κB and p38-MAPK signaling disrupts stromal morphogen production

Androgen Receptor (AR) activity in prostate stroma is required to maintain prostate homeostasis. This is mediated through androgen-dependent induction and secretion of morphogenic factors that drive epithelial cell differentiation. However, stromal AR expression is lost in aggressive prostate cancer. The mechanisms leading to stromal AR loss and morphogen production are unknown. We identified TGFβ1 and TNFα as tumor-secreted factors capable of suppressing AR mRNA and protein expression in prostate stromal fibroblasts. Pharmacological and RNAi approaches identified NF-κB as the major signaling pathway involved in suppressing AR expression by TNFα. In addition, p38α- and p38δ-MAPK were identified as suppressors of AR expression independent of TNFα. Two regions of the AR promoter were responsible for AR suppression through TNFα. FGF10 and Wnt16 were identified as androgen-induced morphogens, whose expression was lost upon TNFα treatment and enhanced upon p38-MAPK inhibition. Wnt16, through non-canonical Jnk signaling, was required for prostate basal epithelial cell survival. These findings indicate that stromal AR loss is mediated by secreted factors within the TME. We identified TNFα/TGFβ as two possible factors, with TNFα mediating its effects through NF-κB or p38-MAPK to suppress AR mRNA transcription. This leads to loss of androgen-regulated stromal morphogens necessary to maintain normal epithelial homeostasis.

Glucocorticoid receptor and specificity protein 1 (Sp1) or Sp3, but not the antibiotic Mithramycin A, stimulates human alphaherpesvirus 1 (HSV-1) replication

Following acute human alphaherpesvirus 1 (HSV-1) infection of oral-facial mucosal surfaces, sensory neurons in trigeminal ganglia (TG) are important sites for life-long latency. Neurons in the central nervous system, including brainstem, also harbor viral genomes during latency. Periodically, certain cellular stressors trigger reactivation from latency, which can lead to recurrent HSV-1 disease: herpes labialis, herpes stromal keratitis, and encephalitis for example. Activation of the glucocorticoid receptor (GR) by stressful stimuli enhances HSV-1 gene expression, replication, and explant-induced reactivation. GR and certain stress-induced Krüppel like factors (KLF) cooperatively transactivate cis-regulatory modules (CRM) that drive expression of viral transcriptional regulatory proteins (ICP0, ICP4, and ICP27). These CRMs lack GR response elements (GRE); however, specificity protein 1 (Sp1) binding sites are crucial for GR and KLF15 or KLF4 mediated transactivation. Hence, we tested whether Sp1 or Sp3 regulate viral replication and transactivation of the ICP0 promoter. During early stages of explant-induced reactivation from latency, the number of Sp3+ TG neurons were significantly higher relative to TG from latently infected mice. Conversely, Sp1+ TG neurons were only increased in females, but not male mice, during explant-induced reactivation. Sp1 siRNA significantly reduced HSV-1 replication in cultured mouse (Neuro-2A) and monkey (CV-1) cells. Mithramycin A, an antibiotic that has anti-tumor activity preferentially interacts with GC-rich DNA, including Sp1 binding sites, significantly reduced HSV-1 replication indicating it has antiviral activity. GR and Sp1 or Sp3 transactivated the HSV-1 ICP0 promoter in Neuro-2A and CV-1 cells confirming these transcription factors enhance viral replication and gene expression.

Dichloroacetic acid and trichloroacetic acid as disinfection by-products in drinking water are endocrine-disrupting chemicals

Dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) are two typical non-volatile disinfection by-products (DBPs) found in drinking water. Increasing evidence has demonstrated that they show reproductive toxicity. However, whether they might have endocrine disrupting properties remains largely unknown. To discover this, we treated male mice or pregnant mice with 0, 1-, 102-, 103-, 104-, or 5 × 104-fold maximal concentration level (MCL) of DCAA or TCAA in drinking water. In male mice, the levels of testosterone in serum and androgen receptor (AR) in testis were declined with ≥ 103-fold MCL of DCAA (26.4 mg/kg/d) or TCAA (52.7 mg/kg/d). In pregnant mice, miscarriage rates were increased with ≥ 104-fold MCL of DCAA (264 mg/kg/d) or ≥ 103-fold MCL of TCAA. The levels of FSH in serum were increased and those of estradiol and progesterone were reduced with ≥ 103-fold MCL of DCAA or TCAA. The protein levels of estrogen receptors (ERα and ERβ) in ovary were reduced with ≥ 102-fold MCL of DCAA (2.64 mg/kg/d) or TCAA (5.27 mg/kg/d). Exposure to some certain fold MCL of DCAA or TCAA also altered the protein levels of ERα and ERβ in uterus and placenta. Exposure to 5 × 104-fold MCL of both DCAA and TCAA showed the combined effects. Therefore, both DCAA and TCAA could be considered as novel reproductive endocrine disrupting chemicals, which might be helpful for further assessment of the toxicological effects of DCAA and TCAA and the awareness of reproductive endocrine disrupting properties caused by DCAA and TCAA in drinking water.

Lifespan Effects of Muscle-Specific Androgen Receptor Overexpression on Body Composition of Male and Female Rats

Androgenic actions of gonadal testosterone are thought to be a major mechanism promoting sex differences in body composition across the lifespan. However, this inference is based on studies of androgen receptor (AR) function in late adolescent or emerging adult rodents. Here we assess body composition and AR expression in skeletal muscle of rats at defined ages, comparing wild-type (WT) to transgenic human skeletal actin-driven AR overexpression (HSAAR) rats which overexpress AR in skeletal muscle. Male and female HSAAR and WT Sprague Dawley rats (N = 288) underwent dual-energy x-ray absorptiometry (DXA) scanning and tissue collection at postnatal day (PND) 1, 10, 21, 42, 70, 183, 243, and 365. Expected sex differences in body composition and muscle mass largely onset with puberty (PND-21), with no associated changes to skeletal muscle AR protein. In adulthood, HSAAR increased tibialis anterior (TA) and extensor digitorum longus mass in males, and reduced the expected gain in gonadal fat mass in both sexes. In WT rats, AR protein was reduced in soleus, but not TA, throughout life. Nonetheless, soleus AR protein expression was greater in male rats than female rats at all ages of sexual development, yet only at PND-70 in TA. Overall, despite muscle AR overexpression effects, results are inconsistent with major sex differences in body composition during sexual development being driven by changes in muscle AR, rather suggesting that changes in ligand promote sexual differentiation of body composition during pubertal timing. Nonetheless, increased skeletal muscle AR in adulthood can be sufficient to increase muscle mass in males, and reduce adipose in both sexes.

International Union of Basic and Clinical Pharmacology CXIII: Nuclear Receptor Superfamily-Update 2023

The NR superfamily comprises 48 transcription factors in humans that control a plethora of gene network programs involved in a wide range of physiologic processes. This review will summarize and discuss recent progress in NR biology and drug development derived from integrating various approaches, including biophysical techniques, structural studies, and translational investigation. We also highlight how defective NR signaling results in various diseases and disorders and how NRs can be targeted for therapeutic intervention via modulation via binding to synthetic lipophilic ligands. Furthermore, we also review recent studies that improved our understanding of NR structure and signaling. SIGNIFICANCE STATEMENT: Nuclear receptors (NRs) are ligand-regulated transcription factors that are critical regulators of myriad physiological processes. NRs serve as receptors for an array of drugs, and in this review, we provide an update on recent research into the roles of these drug targets.

Novel Insights on the Role of Epigenetics in Androgen Receptor's Expression in Prostate Cancer

The androgens/androgen receptor (AR) axis is the main therapeutic target in prostate cancer (PCa). However, while initially responsive, a subset of tumors loses AR expression through mechanisms putatively associated with epigenetic modifications. In this study, we assessed the link between the presence of CpG methylation in the 5'UTR and promoter regions of AR and loss of AR expression. Hence, we characterized and compared the methylation signature at CpG resolution of these regulatory regions in vitro, both at basal levels and following treatment with 5-aza-2-deoxycytidine (DAC) alone, or in combination with Trichostatin A (TSA). Our results showed heterogeneity in the methylation signature of AR negative cell lines and pinpointed the proximal promoter region as the most consistently methylated site in DU-145. Furthermore, this region was extremely resistant to the demethylating effects of DAC and was only significantly demethylated upon concomitant treatment with TSA. Nevertheless, no AR re-expression was detected at the mRNA or protein level. Importantly, after treatment, there was a significant increase in repressive histone marks at AR region 1 in DU-145 cells. Altogether, our data indicate that AR region 1 genomic availability is crucial for AR expression and that the inhibition of histone methyltransferases might hold promise for AR re-expression.

hSSB1 (NABP2/OBFC2B) modulates the DNA damage and androgen-induced transcriptional response in prostate cancer

BACKGROUND

Activation and regulation of androgen receptor (AR) signaling and the DNA damage response impact the prostate cancer (PCa) treatment modalities of androgen deprivation therapy (ADT) and radiotherapy. Here, we have evaluated a role for human single-strand binding protein 1 (hSSB1/NABP2) in modulation of the cellular response to androgens and ionizing radiation (IR). hSSB1 has defined roles in transcription and maintenance of genome stability, yet little is known about this protein in PCa.

METHODS

We correlated hSSB1 with measures of genomic instability across available PCa cases from The Cancer Genome Atlas (TCGA). Microarray and subsequent pathway and transcription factor enrichment analysis were performed on LNCaP and DU145 prostate cancer cells.

RESULTS

Our data demonstrate that hSSB1 expression in PCa correlates with measures of genomic instability including multigene signatures and genomic scars that are reflective of defects in the repair of DNA double-strand breaks via homologous recombination. In response to IR-induced DNA damage, we demonstrate that hSSB1 regulates cellular pathways that control cell cycle progression and the associated checkpoints. In keeping with a role for hSSB1 in transcription, our analysis revealed that hSSB1 negatively modulates p53 and RNA polymerase II transcription in PCa. Of relevance to PCa pathology, our findings highlight a transcriptional role for hSSB1 in regulating the androgen response. We identified that AR function is predicted to be impacted by hSSB1 depletion, whereby this protein is required to modulate AR gene activity in PCa.

CONCLUSIONS

Our findings point to a key role for hSSB1 in mediating the cellular response to androgen and DNA damage via modulation of transcription. Exploiting hSSB1 in PCa might yield benefits as a strategy to ensure a durable response to ADT and/or radiotherapy and improved patient outcomes.

Evolutionary endocrinology and the problem of Darwin's tangled bank

Like Darwin's tangled bank of biodiversity, the endocrine mechanisms that give rise to phenotypic diversity also exhibit nearly endless forms. This tangled bank of mechanistic diversity can prove problematic as we seek general principles on the role of endocrine mechanisms in phenotypic evolution. A key unresolved question is therefore: to what degree are specific endocrine mechanisms re-used to bring about replicated phenotypic evolution? Related areas of inquiry are booming in molecular ecology, but behavioral traits are underrepresented in this literature. Here, I leverage the rich comparative tradition in evolutionary endocrinology to evaluate whether and how certain mechanisms may be repeated hotspots of behavioral evolutionary change. At one extreme, mechanisms may be parallel, such that evolution repeatedly uses the same gene or pathway to arrive at multiple independent (or, convergent) origins of a particular behavioral trait. At the other extreme, the building blocks of behavior may be unique, such that outwardly similar phenotypes are generated via lineage-specific mechanisms. This review synthesizes existing case studies, phylogenetic analyses, and experimental evolutionary research on mechanistic parallelism in animal behavior. These examples show that the endocrine building blocks of behavior have some elements of parallelism across replicated evolutionary events. However, support for parallelism is variable among studies, at least some of which relates to the level of complexity at which we consider sameness (i.e. pathway vs. gene level). Moving forward, we need continued experimentation and better testing of neutral models to understand whether, how - and critically, why - mechanism A is used in one lineage and mechanism B is used in another. We also need continued growth of large-scale comparative analyses, especially those that can evaluate which endocrine parameters are more or less likely to undergo parallel evolution alongside specific behavioral traits. These efforts will ultimately deepen understanding of how and why hormone-mediated behaviors are constructed the way that they are.

The role of testosterone in men's health: is it time for a new approach?

PURPOSE

Because of many unanswered questions regarding men's health, a literature review was performed to better understand the role of testosterone and testosterone replacement therapy (TRT) in the management of hypogonadism and aging related prostate gland diseases (ARPGD) including prostate cancer (PCa) and benign prostatic hyperplasia (BPH) with lower urinary tract symptoms (LUTS).

METHODS

The PubMed database was screened for pertinent peer reviewed articles published during the last four decades that culminated in the positions and recommendations in this paper.

RESULTS

Hypogonadism seriously impacts men's health, and the diagnosis remains controversial. The incidence of ARPGD is projected to increase worldwide and treatment still has significant limitations. There is compelling evidence that lower, not higher, testosterone levels trigger the development of PCa and BPH through androgen receptor over-expression. TRT was found to be safe and effective in treating hypogonadism including in PCa survivors and those harboring PCa. There is also evidence that TRT might reduce the incidence and prevalence of ARPGD.

CONCLUSIONS AND RECOMMENDATIONS

This review synthesizes a wide-ranging compendium of basic science and clinical research that strongly encourages altering the present approach to diagnosing and treating men with hypogonadism and ARPGD. These findings underscore the importance of avoiding significant testosterone decline and support the use of TRT. Ten recommendations are offered as a framework for the way forward. It is now time for clinicians, payers, researchers, funding agencies, professional associations, and patient advocacy groups to embrace this new paradigm to increase longevity and improve the quality of life.

Basics of androgen synthesis and action

Androgens are essential sex steroid hormones for both sexes. Testosterone (T) is the predominant androgen in males, while in adult females, T concentrations are about 15-fold lower and androgen precursors are converted to estrogens. T is produced primarily in testicular Leydig cells in men, while in women precursors are biosynthesised in the adrenal cortex and ovaries and converted into T in the periphery. The biosynthesis of T occurs via a series of enzymatic reactions in steroidogenic organs. Notably, the more potent androgen, dihydrotestosterone, may be synthesized from T in the classic pathway, however, alternate metabolic pathways also exist. The classic action of androgens on target organs is mediated through the androgen receptor, which regulates nuclear receptor gene transcription. However, the androgen-androgen receptor complex may also interact directly with membrane proteins or signaling molecules to exert more rapid effects. This review summarizes the current knowledge of androgen biosynthesis, mechanisms of action and endocrine effects in human biology, and relates these effects to respective human congenital and acquired disorders.

Drugging the Undruggable: Targeting the N-Terminal Domain of Nuclear Hormone Receptors

This chapter focuses on the development of drugs targeting the N-terminal domain of nuclear hormone receptors, using progress with the androgen receptor as an example. Historically, development of therapies targeting nuclear hormone receptors has focused on the folded C-terminal ligand-binding domain. Therapies were traditionally not developed to target the intrinsically disordered N-terminal domain as it was considered "undruggable". Recent developments have now shown it is possible to direct therapies to the N-terminal domain. This chapter will provide an introduction of the structure and function of the domains of nuclear hormone receptors, followed by a discussion of the rationale supporting the development of N-terminal domain inhibitors. Chemistry and mechanisms of action of small molecule inhibitors will be described with emphasis on N-terminal domain inhibitors developed to the androgen receptor including those in clinical trials.

Role of the renal androgen receptor in sex differences in ammonia metabolism

There are sex differences in renal ammonia metabolism and structure, many of which are mediated by testosterone. The goal of the present study was to determine the role of renal expression of testosterone's canonical receptor, androgen receptor (AR), in these sexual dimorphisms. We studied mice with kidney-specific AR deletion [KS-AR-knockout (KO)] generated using Cre/loxP techniques; control mice were Cre-negative littermates (wild type). In male but not female mice, KS-AR-KO increased ammonia excretion, which eliminated sex differences. Although renal structural size typically parallel ammonia excretion, KS-AR-KO decreased kidney size, cortical proximal tubule volume density, and cortical proximal tubule cell height in males-neither were altered in females and collecting duct volume density was unaltered in both sexes. Analysis of key protein involved in ammonia handling showed in male mice that KS-AR-KO increased both phosphoenolpyruvate carboxykinase (PEPCK) and Na+-K+-2Cl- cotransporter (NKCC2) expression and decreased Na+/H+ exchanger isoform 3 (NHE3) and electrogenic Na+-bicarbonate cotransporter 1 (NBCe1)-A expression. In female mice, KS-AR-KO did not alter these parameters. These effects occurred even though KS-AR-KO did not alter plasma testosterone, food intake, or serum Na+, K+, or [Formula: see text] significantly in either sex. In conclusion, AR-dependent signaling pathways in male, but not female, kidneys regulate PEPCK and NKCC2 expression and lead to the sexual differences in ammonia excretion. Opposing effects on NHE3 and NBCe1-A expression likely limit the magnitude of ammonia excretion changes. As AR is not present in the thick ascending limb, the effect of KS-AR-KO on NKCC2 expression is indirect. Finally, AR mediates the greater kidney size and proximal tubule volume density in male compared with female mice.NEW & NOTEWORTHY Sexual dimorphisms in ammonia metabolism involve androgen receptor (AR)-dependent signaling pathways in male, but not female, kidneys that lead to altered proximal tubule (PT), phosphoenolpyruvate carboxykinase, and thick ascending limb Na+-K+-2Cl- cotransporter expression. Adaptive responses in Na+/H+ exchanger 3 and electrogenic Na+-bicarbonate cotransporter 1-A expression limit the magnitude of the effect on ammonia excretion. Finally, the greater kidney size and PT volume density in male mice is the result of PT androgen signaling through AR.

In utero exposure to phenanthrene induced islet cell dysfunction in adult mice: Sex differences in the effects and potential causes

Epidemiological studies show that the burden of polycyclic aromatic hydrocarbons in human body is associated with the occurrence of insulin resistance and diabetes. In the present study, pregnant mice were exposed to phenanthrene (Phe) at doses of 0, 60 and 600 μg/kg body weight of by gavage once every 3 days. The female F1 mice at 120 days of age showed no change in their fasting glucose levels (FGLs) but exhibited significantly decreased homeostasis model assessment (HOMA) β-cell (49% and 43%) and significantly downregulated pancreatic proinsulin gene (ins2) transcription. The downregulation of transcription factors, such as PDX1, PAX4 and FGF21, indicated impaired development and function of β-cells. The significantly reduced α-cell mass in 60 and 600 μg/kg groups, and the significantly downregulated expression of proglucagon gene gcg and ARX in the 600 μg/kg group suggested that the development and function of α-cells had been impacted. The males exhibited significantly increased FGLs (1.14- and 1.15-fold) in Phe exposed treatments and significantly elevated HOMA β-cell (3.15-fold) in the 600 μg/kg group. Upregulated ins2 transcription and FGF21 protein in male mice prenatally exposed to 600 μg/kg Phe suggested that these animals appeared compensatory enhancement in β-cell function. The reduced serum estradiol levels and downregulated pancreatic estrogen receptor α and β were responsible for the dysfunction of β-cells in the females. In the males, the significantly elevated androgen levels in the 600 μg/kg group might be related to the upregulated ins2 transcription, and the increased expression of pancreatic FGF21 further demonstrated the enhancement of β-cell potential. The results will be helpful for assessing the risk of developing diabetes in adulthood after prenatal exposure to phenanthrene.

The function of BAP18 on modulation of androgen receptor action in luteinized granulosa cells from normal weight women with and without PCOS

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in reproductive-age women. In this study, BPTF associated protein of 18 kDa (BAP18) is decreased in luteinized granulosa cells (GCs) from PCOS women. BAP18 depletion significantly decreases CYP19A1 expression levels, leading to an abrogation in transfer capacity of androgen to estrogen in GCs. Also, BAP18 knockdown delays cell cycle G1 to S phase transition and induces cell apoptosis to decrease GCs proliferation. We also provide evidence showing BAP18 interacts with androgen receptor (AR) and enhances AR-mediated transactivation in GCs. Results indicate that AR or BAP18 recruits to androgen response elements (AREs) of CYP19A1 and FSHR, which are putative AR-induced genes in GCs. BAP18 interacts with Sp1 transcription factor and co-recruits to the promoter region of AR gene, resulting in AR transactivation in GCs. Taken together, these data provide new insights on the pathophysiology of PCOS.

Androgen receptor DNA methylation is an independent determinant of glucose metabolic disorders in women; testosterone plays a moderating effect

BACKGROUND

We have previously shown that serum testosterone was associated with impaired fasting glucose (IFG) and type 2 diabetes (T2D). Testosterone can be acting through binding the androgen receptor (AR). Therefore, we aimed to explore the independent associations of AR DNA methylation (ARm) with IFG and T2D and the moderation effects of serum testosterone on the associations.

METHODS

A case-control study with 1065 participants including 461 men and 604 women was performed. ARm in peripheral blood sample and serum testosterone were measured using pyrosequeuncing and liquid chromatography-tandem mass, respectively. Multivariable logistic regression was performed to estimate the associations of ARm (including 2 cytosine-phosphoguanine [CpG] islands and average methylation levels) with different glucose status. Serum testosterone was used as a moderator to estimate the moderation effect.

RESULTS

After multivariate adjustment, CpG 1, 2 and CpG average methylation were all significantly associated with IFG (CpG 1: Odds ratio (OR) = 4.80, 95% confidence interval (CI): 2.24-10.27; CpG 2: OR = 4.35, 95% CI: 2.50-7.58; CpG average: OR = 11.73, 95% CI: 5.36-25.67) in women. In addition, testosterone played negative moderation effects in above associations. Moreover, no significant independent associations of methylation levels with T2D was observed both in men and women.

CONCLUSION

Our findings demonstrate that ARm was positively associated with IFG in women and the associations would be weakened by testosterone. The individuals experiencing low testosterone and ARm levels reported a lower state of IFG than those who experienced high levels of testosterone and ARm in women.

Androgen receptors in areas of the spinal cord and brainstem: A study in adult male cats

Sex hormones, including androgens and estrogens, play an important role in autonomic, reproductive and sexual behavior. The areas that are important in these behaviors lie within the spinal cord and brainstem. Relevant dysfunctional behavior in patients with altered androgen availability or androgen receptor sensitivity might be explained by the distribution of androgens and their receptors in the central nervous system. We hypothesize that autonomic dysfunction is correlated with the androgen sensitivity of spinal cord and brainstem areas responsible for autonomic functions. In this study, androgen receptor immunoreactive (AR‐IR) nuclei in the spinal cord and brainstem were studied using the androgen receptor antibody PG21 in four uncastrated young adult male cats. A dense distribution of AR‐IR nuclei was detected in the superior layers of the dorsal horn, including lamina I. Intensely stained nuclei, but less densely distributed, were found in lamina X and preganglionic sympathetic and parasympathetic cells of the intermediolateral cell column. Areas in the caudal brainstem showing a high density of AR‐IR nuclei included the area postrema, the dorsal motor vagus nucleus and the retrotrapezoid nucleus. More cranially, the central linear nucleus in the pons contained a dense distribution of AR‐IR nuclei. The mesencephalic periaqueductal gray (PAG) showed a dense distribution of AR‐IR nuclei apart from the most central part of the PAG directly adjacent to the ependymal lining. Other areas in the mesencephalon with a dense distribution of AR‐IR nuclei were the dorsal raphe nucleus, the retrorubral nucleus, the substantia nigra and the ventral tegmental area of Tsai. It is concluded that AR‐IR nuclei are located in specific areas of the central nervous system that are involved in the control of sensory function and autonomic behavior. Furthermore, damage of these AR‐IR areas might explain related dysfunction in humans.

Sex differences in renal ammonia metabolism

Sexual dimorphic variations are present in many aspects of biology and involve the structure and/or function of nearly every organ system. Acid-base homeostasis is critical for optimal health, and renal ammonia metabolism has a major role in the maintenance of acid-base homeostasis. Recent studies have shown sex-dependent differences in renal ammonia metabolism with regard to both basal ammonia excretion and the response to an exogenous acid load. These sexual dimorphisms are associated with structural changes in the proximal tubule and the collecting duct and variations in the expression of multiple proteins involved in ammonia metabolism and transport. Studies using orchiectomy-induced testosterone deficiency and physiological testosterone replacement have shown that testosterone underlies much of the sex-dependent differences in the proximal tubule. This parallels the finding that the canonical testosterone target receptor, androgen receptor (AR), is present exclusively in the proximal tubule. Thus testosterone, possibly acting through AR activation, regulates multiple components of renal structure and ammonia metabolism. The lack of detectable AR in the remainder of the nephron and collecting duct suggests that some dimorphisms in renal structure and ammonia transporter expression are mediated through mechanisms other than direct testosterone-dependent AR activation. A better understanding of the mechanism and biological implications of sex's effect on renal structure and ammonia metabolism is critical for optimizing our ability to care for both men and women with acid-base disturbances.

A Testis-Specific Long Noncoding RNA, Start, Is a Regulator of Steroidogenesis in Mouse Leydig Cells

The testis expresses many long noncoding RNAs (lncRNAs), but their functions and overview of lncRNA variety are not well understood. The mouse Prss/Tessp locus contains six serine protease genes and two lncRNAs that have been suggested to play important roles in spermatogenesis. Here, we found a novel testis-specific lncRNA, Start (Steroidogenesis activating lncRNA in testis), in this locus. Start is 1822 nucleotides in length and was found to be localized mostly in the cytosol of germ cells and Leydig cells, although nuclear localization was also observed. Start-knockout (KO) mice generated by the CRISPR/Cas9 system were fertile and showed no morphological abnormality in adults. However, in adult Start-KO testes, RNA-seq and qRT-PCR analyses revealed an increase in the expression of steroidogenic genes such as Star and Hsd3b1, while ELISA analysis revealed that the testosterone levels in serum and testis were significantly low. Interestingly, at 8 days postpartum, both steroidogenic gene expression and testosterone level were decreased in Start-KO mice. Since overexpression of Start in two Leydig-derived cell lines resulted in elevation of the expression of steroidogenic genes including Star and Hsd3b1, Start is likely to be involved in their upregulation. The increase in expression of steroidogenic genes in adult Start-KO testes might be caused by a secondary effect via the androgen receptor autocrine pathway or the hypothalamus-pituitary-gonadal axis. Additionally, we observed a reduced number of Leydig cells at 8 days postpartum. Collectively, our results strongly suggest that Start is a regulator of steroidogenesis in Leydig cells. The current study provides an insight into the overall picture of the function of testis lncRNAs.

Disruption of classical estrogenic targets in brown trout primary hepatocytes by the model androgens testosterone and dihydrotestosterone

Estrogenic effects triggered by androgens have been previously shown in a few studies. Aromatization and direct binding to estrogen receptors (ERs) are the most proposed mechanisms. For example, previously, a modulation of vitellogenin A (VtgA) by testosterone (T), an aromatizable androgen, was reported in brown trout primary hepatocytes. The effect was reversed by an ER antagonist. In this study, using the same model the disruption caused by T and by the non-aromatizable androgen - dihydrotestosterone (DHT), was assessed in selected estrogenic targets. Hepatocytes were exposed (96 h) to six concentrations of each androgen. The estrogenic targets were VtgA, ERα, ERβ1 and two zona pellucida genes, ZP2.5 and ZP3a.2. The aromatase CYP19a1 gene and the androgen receptor (AR) were also included. Modulation of estrogenic targets was studied by quantitative real-time PCR and immunohistochemistry, using an HScore system. VtgA and ERα were up-regulated by DHT (1, 10, 100 μM) and T (10, 100 μM). In contrast, ERβ1 was down-regulated by DHT (10, 100 μM), and T (100 μM). ZP2.5 mRNA levels were increased by DHT and T (1, 10, 100 μM), while ZP3a.2 was up-regulated by DHT (100 μM) and T (10, 100 μM). Positive correlations were found between VtgA and ERα mRNA levels and ZPs and ERα, after exposure to both androgens. The mRNA levels of CYP19a1 were not changed, while AR expression tended to increase after micromolar DHT exposures. HScores for Vtg and ZPs corroborated the molecular findings. Both androgens triggered estrogen signaling through direct binding to ERs, most probably ERα.

Comparative study of the effects of osteoprotegerin and testosterone on bone quality in male orchidectomised rats

Aim: The aim of this work is to compare the effects of osteoprotegerin (OPG) and testosterone on bone quality in a model of orchidectomised (ORX) rats.Methods: Three-month-old ORX or SHAM operated groups (n = 15 each group) were used. The SHAM and ORX groups received saline. There were two ORX groups, receiving OPG-Fc (10 mg/kg twice weekly) (ORX + OPG-Fc) or testosterone cypionate (1.7 mg/kg/weekly) for 8 weeks. After sacrifice, bone analysis by femoral and lumbar dual-energy X-ray absorptiometry and micro-computed tomography in femora were performed. Histological sections of vertebrae were dyed with hematoxylin-eosin or safranin. Serum osteocalcin (BGP), total alkaline phosphatase (ALP), and C-terminal telopeptide of type I collagen (CTX) were analyzed.Results: ORX resulted in femoral and vertebral bone loss and in microarchitectural deterioration. Treatment with OPG-Fc and testosterone recovered lumbar (L) and femoral (F) bone mineral densitometry bone mineral density (BMD) to SHAM levels. Femoral BMD was significantly higher after treatment with OPG-Fc than after testosterone treatment due to the presence of osteopetrotic changes in the metaphyseal region of long bones. Serum levels of ALP and CTX increased, while OPG levels were unchanged in ORX rats. Treatment with OPG-Fc decreased the levels of BGP, ALP, and CTX. Treatment with testosterone maintained biochemical markers of bone turnover at levels similar to or higher than those of ORX rats.

How research on female vertebrates contributes to an expanded challenge hypothesis

The bi-directional links between hormones and behavior have been a rich area of research for decades. Theory on the evolution of testosterone (T) was greatly advanced by the challenge hypothesis, which presented a framework for understanding interspecific, seasonal, and social variation in T levels in males, and how they are shaped by the competing demands of parental care and male-male competition. Female competition is also widespread in nature, although it is less clear whether or how the challenge hypothesis applies to females. Here, we evaluate this issue in four parts: (1) We summarize and update prior analyses of seasonal plasticity and interspecific variation in T in females. (2) We evaluate experimental links between T and female aggression on shorter timescales, asking how T manipulations affect aggression and conversely, how social manipulations affect T levels in female mammals, birds, lizards, and fishes. (3) We examine alternative mechanisms that may link aggression to the social environment independently of T levels in circulation. (4) We present a case study, including new data analyses, in an aggressive female bird (the tree swallow, Tachycineta bicolor) to explore how variation in tissue-level processing of T may bridge the gap between circulating T and variation in behavior that is visible to natural selection. We close by connecting these multivariate levels of sex steroid signaling systems alongside different temporal scales (social, seasonal, and evolutionary) to generate broadly applicable insights into how animals respond to their social environment, regardless of whether they are male or female.

Sex differences in testosterone reactivity and sensitivity in a non-model gerbil

Although testosterone (T) is a key regulator in vertebrate development, physiology, and behaviour in both sexes, studies suggest that its regulation may be sex-specific. We measured circulating T levels in Baluchistan gerbils (Gerbillus nanus) in the field and in the lab all year round and found no significant sex differences. However, we observed sex differences in circulating T levels following gonadotropin-releasing hormone (GnRH) challenge and T implants in this non-model species. Whereas only males elevated T following a GnRH challenge, females had higher serum T concentrations following T implant insertion. These differences may be a result of different points of regulation along the hypothalamic-pituitary-gonadal (HPG) axis. Consequently, we examined sex differences in the mRNA expression of the androgen receptor (AR) in multiple brain regions. We identified AR and β-actin sequences in assembled genomic sequences of members of the Gerbillinae, which were analogous to rat sequences, and designed primers for them. The distribution of the AR in G. nanus brain regions was similar to documented expression profiles in rodents. We found lower AR mRNA levels in females in the striatum. Additionally, G. nanus that experienced housing in mixed-sex pairs had higher adrenal AR expression than G. nanus that were housed alone. Regulation of the gerbil HPG axis may reflect evolutionary sex differences in life-history strategies, with males ready to reproduce when receptive females are available, while the possible reproductive costs associated with female T direct its regulation upstream.

AR pathway activity correlates with AR expression in a HER2-dependent manner and serves as a better prognostic factor in breast cancer

BACKGROUND

Androgen receptor (AR) antagonists are currently tested in multiple clinical trials for different breast cancer (BC) subtypes, which emphasizes the need for clarifying the role of AR in this type of cancer. Previous studies showed that AR expression was associated with a favorable prognosis in ER-positive BC. However, the true biological effect of AR signaling in BC is not clear.

METHODS

An AR pathway signature was generated to compute AR pathway activity in BCs (n = 6439) from 46 microarray datasets. Associations of AR pathway activity and AR expression with BC prognosis were compared by survival analysis.

RESULTS

AR pathway activity showed moderate positive and negative correlations with AR expression in HER2-positive and HER2-negative BCs, respectively. AR pathway activity increased while AR expression decreased in ER-negative BCs. Like ER and progesterone receptor (PR) expression, AR expression was also negatively associated with tumor grade, neoadjuvant response, and recurrence risk in BC. By contrast, AR pathway activity was positively, and more significantly, associated with these clinical features. Moreover, the AR pathway, but not AR expression, was significantly associated with recurrence risk in BC patients treated with endocrine therapy. These data suggest that, although AR expression probably reflects well-differentiated states of BC and is thus associated with favorable prognosis in BC, the biological effects of AR signaling confers worse outcomes in BC.

CONCLUSIONS

Our findings encourage the continued evaluation of AR antagonists for BC treatment and support that AR pathway activity serves as a better prognostic factor than AR expression in BC.

Evidence for enhanced androgen action in the prefrontal cortex of people with bipolar disorder but not schizophrenia or major depressive disorder

Anxiety and depressive disorders are more prevalent in hypogonadal men. Low testosterone levels are associated with greater negative symptoms and impaired cognition in men with schizophrenia. Thus, androgens may contribute to brain pathophysiology in psychiatric disorders. We investigated androgen-related mRNAs in post-mortem dorsolateral prefrontal cortex of psychiatric disorders. We also assessed androgen receptor (AR) CAG trinucleotide repeat length, a functional AR gene variant associated with AR gene expression, receptor activity, and circulating testosterone. AR CAG repeat length was determined from genomic DNA and AR and 5α-reductase mRNAs measured using quantitative PCR in schizophrenia, bipolar disorder and control cases [n = 35/group; Stanley Medical Research Institute (SMRI) Array collection]. Layer-specific AR gene expression was determined using in situ hybridisation in schizophrenia, bipolar disorder, major depressive disorder and control cases (n = 15/group; SMRI Neuropathology Consortium). AR mRNA was increased in bipolar disorder, but was unchanged in schizophrenia, relative to controls. AR and 5α-reductase mRNAs were significantly positively correlated in bipolar disorder. AR CAG repeat length was significantly shorter in bipolar disorder relative to schizophrenia. AR mRNA expression was highest in cortical layers IV and V, but no layer-specific diagnostic differences were detected. Together, our results suggest enhanced cortical androgen action in people with bipolar disorder.

Evaluating testosterone as a phenotypic integrator: From tissues to individuals to species

Hormones have the potential to bring about rapid phenotypic change; however, they are highly conserved over millions of years of evolution. Here, we examine the evolution of hormone-mediated phenotypes, and the extent to which regulation is achieved via independence or integration of the many components of endocrine systems. We focus on the sex steroid testosterone (T), its cognate receptor (androgen receptor) and related endocrine components. We pose predictions about the mechanisms underlying phenotypic integration, including coordinated sensitivity to T within and among tissues and along the HPG axis. We then assess these predictions with case studies from wild birds, asking whether gene expression related to androgenic signaling naturally co-varies among individuals in ways that would promote phenotypic integration. Finally, we review how mechanisms of integration and independence vary over developmental or evolutionary time, and we find limited support for integration.

Importance of the Androgen Receptor Signaling in Gene Transactivation and Transrepression for Pubertal Maturation of the Testis

Androgens are key for pubertal development of the mammalian testis, a phenomenon that is tightly linked to Sertoli cell maturation. In this review, we discuss how androgen signaling affects Sertoli cell function and morphology by concomitantly inhibiting some processes and promoting others that contribute jointly to the completion of spermatogenesis. We focus on the molecular mechanisms that underlie anti-Müllerian hormone (AMH) inhibition by androgens at puberty, as well as on the role androgens have on Sertoli cell tight junction formation and maintenance and, consequently, on its effect on proper germ cell differentiation and meiotic onset during spermatogenesis.

Molecules targeting the androgen receptor (AR) signaling axis beyond the AR-Ligand binding domain

Prostate cancer (PCa) is the second most common cause of cancer-related mortality in men in the United States. The androgen receptor (AR) and the physiological pathways it regulates are central to the initiation and progression of PCa. As a member of the nuclear steroid receptor family, it is a transcription factor with three distinct functional domains (ligand-binding domain [LBD], DNA-binding domain [DBD], and transactivation domain [TAD]) in its structure. All clinically approved drugs for PCa ultimately target the AR-LBD. Clinically active drugs that target the DBD and TAD have not yet been developed due to multiple factors. Despite these limitations, the last several years have seen a rise in the discovery of molecules that could successfully target these domains. This review aims to present and comprehensively discuss such molecules that affect AR signaling through direct or indirect interactions with the AR-TAD or the DBD. The compounds discussed here include hairpin polyamides, niclosamide, marine sponge-derived small molecules (eg, EPI compounds), mahanine, VPC compounds, JN compounds, and bromodomain and extraterminal domain inhibitors. We highlight the significant in vitro and in vivo data found for each compound and the apparent limitations and/or potential for further development of these agents as PCa therapies.

Epigenetic Repression of Androgen Receptor Transcription in Mutation-Negative Androgen Insensitivity Syndrome (AIS Type II)

CONTEXT

Inactivating mutations within the AR gene are present in only ~40% of individuals with clinically and hormonally diagnosed androgen insensitivity syndrome (AIS). Previous studies revealed the existence of an AR gene mutation-negative group of patients with AIS who have compromised androgen receptor (AR) function (AIS type II).

OBJECTIVE

To investigate whether AIS type II can be due to epigenetic repression of AR transcription.

DESIGN

Quantification of AR mRNA and AR proximal promoter CpG methylation levels in genital skin-derived fibroblasts (GFs) derived from patients with AIS type II and control individuals.

SETTING

University hospital endocrine research laboratory.

PATIENTS

GFs from control individuals (n = 11) and patients with AIS type II (n = 14).

MAIN OUTCOME MEASURE(S)

Measurement of AR mRNA and AR promoter CpG methylation as well as activity of AR proximal promoter in vitro.

RESULTS

Fifty-seven percent of individuals with AIS type II (n = 8) showed a reduced AR mRNA expression in their GFs. A significant inverse correlation was shown between AR mRNA abundance and methylation at two consecutive CpGs within the proximal AR promoter. Methylation of a 158-bp-long region containing these CpGs was sufficient to severely reduce reporter gene expression. This region was bound by the runt related transcription factor 1 (RUNX1). Ectopic expression of RUNX1 in HEK293T cells was able to inhibit reporter gene expression through this region.

CONCLUSIONS

Aberrant CpGs methylation within the proximal AR promoter plays an important role in the control of AR gene expression and may result in AIS type II. We suggest that transcriptional modifiers, such as RUNX1, could play roles therein offering new perspectives for understanding androgen-mediated endocrine diseases.