11beta-hydroxysteroid dehydrogenase: unexpected connections

Drug development and potential targets for Cushing's syndrome

Cushing's syndrome (CS) is a complex disorder characterized by the excessive secretion of cortisol, with Cushing's disease (CD), particularly associated with pituitary tumors, exhibiting heightened morbidity and mortality. Although transsphenoidal pituitary surgery (TSS) stands as the primary treatment for CD, there is a crucial need to optimize patient prognosis. Current medical therapy serves as an adjunctive measure due to its unsatisfactory efficacy and unpredictable side effects. In this comprehensive review, we delve into recent advances in understanding the pathogenesis of CS and explore therapeutic options by conducting a critical analysis of potential drug targets and candidates. Additionally, we provide an overview of the design strategy employed in previously reported candidates, along with a summary of structure-activity relationship (SAR) analyses and their biological efficacy. This review aims to contribute valuable insights to the evolving landscape of CS research, shedding light on potential avenues for therapeutic development.

11β-Hydroxysteroid Dehydrogenase Type 1 as a Potential Treatment Target in Cardiovascular Diseases

Glucocorticoids (GCs) belong to the group of steroid hormones. Their representative in humans is cortisol. GCs are involved in most physiological processes of the body and play a significant role in important biological processes, including reproduction, growth, immune responses, metabolism, maintenance of water and electrolyte balance, functioning of the central nervous system and the cardiovascular system. The availability of cortisol to the glucocorticoid receptor is locally controlled by the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Evidence of changes in intracellular GC metabolism in the pathogenesis of obesity, metabolic syndrome (MetS) and cardiovascular complications highlights the role of selective 11β-HSD1 inhibition in the pharmacotherapy of these diseases. This paper discusses the role of 11β-HSD1 in MetS and its cardiovascular complications and the importance of selective inhibition of 11β-HSD1.

How exposure to chronic stress contributes to the development of type 2 diabetes: A complexity science approach

Chronic stress contributes to the onset of type 2 diabetes (T2D), yet the underlying etiological mechanisms are not fully understood. Responses to stress are influenced by earlier experiences, sex, emotions and cognition, and involve a complex network of neurotransmitters and hormones, that affect multiple biological systems. In addition, the systems activated by stress can be altered by behavioral, metabolic and environmental factors. The impact of stress on metabolic health can thus be considered an emergent process, involving different types of interactions between multiple variables, that are driven by non-linear dynamics at different spatiotemporal scales. To obtain a more comprehensive picture of the links between chronic stress and T2D, we followed a complexity science approach to build a causal loop diagram (CLD) connecting the various mediators and processes involved in stress responses relevant for T2D pathogenesis. This CLD could help develop novel computational models and formulate new hypotheses regarding disease etiology.

Mutual regulations and breast cancer cell control by steroidogenic enzymes: Dual sex-hormone receptor modulation upon 17β-HSD7 inhibition

Reductive 17β-hydroxysteroid dehydrogenases (17β-HSDs) and 11β-hydroxysteroid dehydrogenase 2 (11β-HSD2) play crucial roles in respectively regulating steroids and glucocorticoids for the progression of hormone-dependent breast cancer. Most studies focused on the function and individual regulation of these enzymes. However, mutual regulation of these enzymes and the induced modulation on the estrogen and androgen receptors for breast cancer promotion are not yet clear. In this study, MCF-7 and T47D cells were treated with inhibitors of 17β-HSD1, 17β-HSD7, aromatase or steroid sulfatase (STS), then mRNA levels of 17β-HSD7, STS, 11β-HSD 2, estrogen receptors α (ERα) and androgen receptor (AR) were determined by Q-PCR. ER negative cell line MDA-MB-231 was used as a negative control. Our results demonstrate that 17β-HSD7, STS and 11β-HSD2 are all regulated by the same estrogen estradiol via ERα. When the gene of ERα (ESR1) was knocked down, there was no longer significant mutual regulation of these enzymes. Our results demonstrate that important steroidogenic enzymes transcriptionally regulated by ERα, can be mutually closely correlated. Inhibition of one of them can reduce the expression of another, thereby amplifying the role of the inhibition. Furthermore, inhibition of 17β-HSD7 increases the expression of AR gene which is considered as a marker for better prognosis in ER + breast cancer, while maintaining ERα level. Thus, our mechanistic finding provides a base for further improving the endocrine therapy of ER + breast cancer, e.g., for selecting the target steroid enzymes, and for the combined targeting of human 17β-HSD7 and ERα.

Potential Anti-obesity and Lipid Lowering Natural Products: A Review

Obesity has reached epidemic proportions globally, with more than 1 billion adults overweight - at least 300 million of them clinically obese. In Ayurveda, obesity is called ‘medoroga’. The detailed features and treatments of the disease have been described in an old Ayurvedic text, Charak and Sushrut Samhita. There are some native plants that are commonly used for the treatment of obesity in Ayurveda. Unfortunately, only few medications are available in the market, with side effects and unacceptable efficacy. With the current view that botanical drugs can be developed faster and more cheaply than conventional single entity pharmaceuticals, the review mainly focuses on the rationality of their use with appropriate literature data support.

Oral administration of the 11β-hydroxysteroid-dehydrogenase type 1 inhibitor RO5093151 to patients with glaucoma: an adaptive, randomised, placebo-controlled clinical study

Background/aims

Cortisol is involved in the regulation of intraocular pressure (IOP). This study aimed to assess the effect of 11β-hydroxysteroid-dehydrogenase type 1 (11βHSD1) inhibition by oral administration of RO5093151 on IOP.

Methods

The exposure of key ocular compartments following oral administration was assessed in rabbits. An adaptive, randomised, placebo-controlled study gated by a Bayesian decision criterion was performed in 35 patients with primary open angle glaucoma (POAG) or ocular hypertension (OHT). Following a 7-day placebo-controlled run-in period, 200 mg twice daily RO5093151 or placebo (4:1) were administered for 7 days. The extent of 11βHSD1 inhibition was assessed by the ratio of urinary tetrahydrocortisol (5α and 5β)/tetrahydrocortisone (THF/THE). Time-matched IOP assessments were performed.

Results

A high distribution of RO5093151 into the rabbit eye was observed. In humans, a high and sustained inhibition of 11βHSD1 was shown by the decrease of THF/THE from 0.9 at baseline to 0.18 on day 7. There was no statistically significant difference in change of IOP from baseline. In the ‘worse eye’, the adjusted least square mean change from baseline was −2.7 mm Hg (95% CI −4.2 to –1.2) and −2.9(95% CI −5.9 to 0.1) in the RO5093151 and placebo group, respectively.

Conclusions

Despite high inhibition of 11βHSD1 and expected moderate to high tissue distribution in ocular tissues, a 7-day treatment with a high oral dose of RO5093151 did not result in a clinically meaningful effect on IOP in patients with POAG or OHT.

Androgen Receptor: A Complex Therapeutic Target for Breast Cancer

Molecular and histopathological profiling have classified breast cancer into multiple sub-types empowering precision treatment. Although estrogen receptor (ER) and human epidermal growth factor receptor (HER2) are the mainstay therapeutic targets in breast cancer, the androgen receptor (AR) is evolving as a molecular target for cancers that have developed resistance to conventional treatments. The high expression of AR in breast cancer and recent discovery and development of new nonsteroidal drugs targeting the AR provide a strong rationale for exploring it again as a therapeutic target in this disease. Ironically, both nonsteroidal agonists and antagonists for the AR are undergoing clinical trials, making AR a complicated target to understand in breast cancer. This review provides a detailed account of AR’s therapeutic role in breast cancer.

Hepatic Glucocorticoid Receptor Plays a Greater Role Than Adipose GR in Metabolic Syndrome Despite Renal Compensation

Exogenous glucocorticoid administration results in hyperglycemia, insulin resistance, hepatic dyslipidemia, and hypertension, a constellation of findings known as Cushing's syndrome. These effects are mediated by the glucocorticoid receptor (GR). Because GR activation in liver and adipose has been implicated in metabolic syndrome (MS), we wanted to determine the role of GR in these tissues in the development of MS. Because GR knockout (KO) mice (whole-body KO) exhibit perinatal lethality due to respiratory failure, we generated tissue-specific (liver or adipose) GRKO mice using cre-lox technology. Real-time PCR analysis of liver mRNA from dexamethasone-treated wildtype (WT) and liver GRKO mice indicated that hepatic GR regulates the expression of key genes involved in gluconeogenesis and glycogen metabolism. Interestingly, we have observed that liver-specific deletion of GR resulted in a significant increase in mRNA expression of key genes involved in gluconeogenesis and glycogen metabolism in kidney tissue, indicating a compensatory mechanism to maintain glucose homeostasis. We have also observed that GR plays an important role in regulating the mRNA expression of key genes involved in lipid metabolism. Liver GRKO mice demonstrated decreased fat mass and liver glycogen content compared with WT mice administered dexamethasone for 2 weeks. Adipose-specific deletion of GR did not alter glucose tolerance or insulin sensitivity of adipose GRKO mice compared with WT mice administrated dexamethasone. This indicates that liver GR might be more important in development of MS in dexamethasone-treated mice, whereas adipose GR plays a little role in these paradigms.

Diagnosis and treatment of adrenal insufficiency including adrenal crisis: a Japan Endocrine Society clinical practice guideline [Opinion]

This clinical practice guideline of the diagnosis and treatment of adrenal insufficiency (AI) including adrenal crisis was produced on behalf of the Japan Endocrine Society. This evidence-based guideline was developed by a committee including all authors, and was reviewed by a subcommittee of the Japan Endocrine Society. The Japanese version has already been published, and the essential points have been summarized in this English language version. We recommend diagnostic tests, including measurement of basal cortisol and ACTH levels in combination with a rapid ACTH (250 μg corticotropin) test, the CRH test, and for particular situations the insulin tolerance test. Cut-off values in basal and peak cortisol levels after the rapid ACTH or CRH tests are proposed based on the assumption that a peak cortisol level ≥18 μg/dL in the insulin tolerance test indicates normal adrenal function. In adult AI patients, 15-25 mg hydrocortisone (HC) in 2-3 daily doses, depending on adrenal reserve and body weight, is a basic replacement regime for AI. In special situations such as sickness, operations, pregnancy and drug interactions, cautious HC dosing or the correct choice of glucocorticoids is necessary. From long-term treatment, optimal diurnal rhythm and concentration of serum cortisol are important for the prevention of cardiovascular disease and osteoporosis. In maintenance therapy during the growth period of patients with 21-hydroxylase deficiency, proper doses of HC should be used, and long-acting glucocorticoids should not be used. Education and carrying an emergency card are essential for the prevention and rapid treatment of adrenal crisis.

Design of pyrazolo-pyrimidines as 11β-HSD1 inhibitors through optimisation of molecular electrostatic potential

Rapid and efficient lead optimisation through quantification of the molecular electrostatic potential using quantum mechanics.

Time lag between peak concentrations of plasma and salivary cortisol following a stressful procedure in dairy cattle

Background

Measurement of salivary cortisol has been used extensively as a non-invasive alternative to blood sampling to assess adrenal activity in ruminants. However, there is evidence suggesting a considerable delay in the transfer of cortisol from plasma into saliva. Previous studies in cattle have used long sampling intervals making it difficult to characterise the relationship between plasma and salivary cortisol (PLCort and SACort, respectively) concentrations at different time points and determine whether or not such a time lag exist in large ruminants. Therefore, the objective of this study was to characterise the relationship between plasma and salivary cortisol and determine if there is a significant time lag between reaching peak cortisol concentrations in plasma and saliva across a 4.25 h time-period, using short sampling intervals of 10–15 min, following social separation in dairy cattle.

Five cows were separated from their calves at 4 days after calving, and six calves were separated from a group of four peers at 8 weeks of age. Following separation, the animals were moved to an unfamiliar surrounding where they could not see their calves or pen mates. The animals were catheterised with indwelling jugular catheters 1 day before sampling. Blood and saliva samples were obtained simultaneously before and after separation.

Results

In response to the stressors, PLCort and SACort increased reaching peak concentrations 10 and 20 min after separation, respectively. This suggested a 10 min time lag between peak cortisol concentrations in plasma and saliva, which was further confirmed with a time-series analysis. Considering the 10 min time lag, SACort was strongly correlated with PLCort (P < 0.0001).

Conclusions

Salivary cortisol correlates well with plasma cortisol and is a good indicator of the time-dependent variations in cortisol concentrations in plasma following acute stress. However, there is a time lag to reach peak cortisol concentrations in saliva compared to those in plasma, which should be considered when saliva samples are used as the only measure of hypothalamic-pituitary-adrenal axis response to stress in cattle.

Time lag between peak concentrations of plasma and salivary cortisol following a stressful procedure in dairy cattle

BACKGROUND

Measurement of salivary cortisol has been used extensively as a non-invasive alternative to blood sampling to assess adrenal activity in ruminants. However, there is evidence suggesting a considerable delay in the transfer of cortisol from plasma into saliva. Previous studies in cattle have used long sampling intervals making it difficult to characterise the relationship between plasma and salivary cortisol (PLCort and SACort, respectively) concentrations at different time points and determine whether or not such a time lag exist in large ruminants. Therefore, the objective of this study was to characterise the relationship between plasma and salivary cortisol and determine if there is a significant time lag between reaching peak cortisol concentrations in plasma and saliva across a 4.25 h time-period, using short sampling intervals of 10-15 min, following social separation in dairy cattle.Five cows were separated from their calves at 4 days after calving, and six calves were separated from a group of four peers at 8 weeks of age. Following separation, the animals were moved to an unfamiliar surrounding where they could not see their calves or pen mates. The animals were catheterised with indwelling jugular catheters 1 day before sampling. Blood and saliva samples were obtained simultaneously before and after separation.

RESULTS

In response to the stressors, PLCort and SACort increased reaching peak concentrations 10 and 20 min after separation, respectively. This suggested a 10 min time lag between peak cortisol concentrations in plasma and saliva, which was further confirmed with a time-series analysis. Considering the 10 min time lag, SACort was strongly correlated with PLCort (P < 0.0001).

CONCLUSIONS

Salivary cortisol correlates well with plasma cortisol and is a good indicator of the time-dependent variations in cortisol concentrations in plasma following acute stress. However, there is a time lag to reach peak cortisol concentrations in saliva compared to those in plasma, which should be considered when saliva samples are used as the only measure of hypothalamic-pituitary-adrenal axis response to stress in cattle.

Discovery of a potent, selective, and orally bioavailable acidic 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitor: discovery of 2-[(3S)-1-[5-(cyclohexylcarbamoyl)-6-propylsulfanylpyridin-2-yl]-3-piperidyl]acetic acid (AZD4017)

Inhibition of 11β-HSD1 is an attractive mechanism for the treatment of obesity and other elements of the metabolic syndrome. We report here the discovery of a nicotinic amide derived carboxylic acid class of inhibitors that has good potency, selectivity, and pharmacokinetic characteristics. Compound 11i (AZD4017) is an effective inhibitor of 11β-HSD1 in human adipocytes and exhibits good druglike properties and as a consequence was selected for clinical development.

The influence of maternal protein nutrition on offspring development and metabolism: the role of glucocorticoids

The consequences of sub-optimal nutrition through alterations in the macronutrient content of the maternal diet will not simply be reflected in altered neonatal body composition and increased mortality, but are likely to continue into adulthood and confer greater risk of metabolic disease. One mechanism linking manipulations of the maternal environment to an increased risk of later disease is enhanced fetal exposure to glucocorticoids (GC). Tissue sensitivity to cortisol is regulated, in part, by the GC receptor and 11β-hydroxysteroid dehydrogenase (11β-HSD) types 1 and 2. Several studies have shown the effects of maternal undernutrition, particularly low-protein diets, on the programming of GC action in the offspring; however, dietary excess is far more characteristic of the diets consumed by contemporary pregnant women. This study investigated the programming effects of moderate protein supplementation in pigs throughout pregnancy. We have demonstrated an up-regulation of genes involved in GC sensitivity, such as GC receptor and 11β-HSD, in the liver, but have yet to detect any other significant changes in these piglets, with no differences observed in body weight or composition. This increase in GC sensitivity was similar to the programming effects observed following maternal protein restriction or global undernutrition during pregnancy.

The molecular biology, biochemistry, and physiology of human steroidogenesis and its disorders

Steroidogenesis entails processes by which cholesterol is converted to biologically active steroid hormones. Whereas most endocrine texts discuss adrenal, ovarian, testicular, placental, and other steroidogenic processes in a gland-specific fashion, steroidogenesis is better understood as a single process that is repeated in each gland with cell-type-specific variations on a single theme. Thus, understanding steroidogenesis is rooted in an understanding of the biochemistry of the various steroidogenic enzymes and cofactors and the genes that encode them. The first and rate-limiting step in steroidogenesis is the conversion of cholesterol to pregnenolone by a single enzyme, P450scc (CYP11A1), but this enzymatically complex step is subject to multiple regulatory mechanisms, yielding finely tuned quantitative regulation. Qualitative regulation determining the type of steroid to be produced is mediated by many enzymes and cofactors. Steroidogenic enzymes fall into two groups: cytochrome P450 enzymes and hydroxysteroid dehydrogenases. A cytochrome P450 may be either type 1 (in mitochondria) or type 2 (in endoplasmic reticulum), and a hydroxysteroid dehydrogenase may belong to either the aldo-keto reductase or short-chain dehydrogenase/reductase families. The activities of these enzymes are modulated by posttranslational modifications and by cofactors, especially electron-donating redox partners. The elucidation of the precise roles of these various enzymes and cofactors has been greatly facilitated by identifying the genetic bases of rare disorders of steroidogenesis. Some enzymes not principally involved in steroidogenesis may also catalyze extraglandular steroidogenesis, modulating the phenotype expected to result from some mutations. Understanding steroidogenesis is of fundamental importance to understanding disorders of sexual differentiation, reproduction, fertility, hypertension, obesity, and physiological homeostasis.

Structure-based and property-compliant library design of 11β-HSD1 adamantyl amide inhibitors

Multiproperty lead optimization that satisfies multiple biological endpoints remains a challenge in the pursuit of viable drug candidates. Optimization of a given lead compound to one having a desired set of molecular attributes often involves a lengthy iterative process that utilizes existing information, tests hypotheses, and incorporates new data. Within the context of a data-rich corporate setting, computational tools and predictive models have provided the chemists a means for facilitating and streamlining this iterative design process. This chapter discloses an actual library design scenario for following up a lead compound that inhibits 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzyme. The application of computational tools and predictive models in the targeted library design of adamantyl amide 11β-HSD1 inhibitors is described. Specifically, the multiproperty profiling using our proprietary PGVL (Pfizer Global Virtual Library) Hub is discussed in conjunction with the structure-based component of the library design using our in-house docking tool AGDOCK. The docking simulations were based on a piecewise linear potential energy function in combination with an efficient evolutionary programming search engine. The library production protocols and results are also presented.

Inhibitors of 11β-hydroxysteroid dehydrogenase type 1 in antidiabetic therapy

Glucocorticoid action is mediated by glucocorticoid receptor (GR), which upon cortisol binding is activated and regulates the transcriptional expression of target genes and downstream physiological functions. 11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) catalyzes the conversion of inactive cortisone to active cortisol. Since cortisol is also produced through biosynthesis in the adrenal glands, the total cortisol level in a given tissue is determined by both the circulating cortisol concentration and the local 11β-HSD1 activity. 11β-HSD1 is expressed in liver, adipose, brain, and placenta. Since it contributes to the local cortisol levels in these tissues, 11β-HSD1 plays a critical role in glucocorticoid action. The metabolic symptoms caused by glucocorticoid excess in Cushing's syndrome overlap with the characteristics of the metabolic syndrome, suggesting that increased glucocorticoid activity may play a role in the etiology of the metabolic syndrome. Consistent with this notion, elevated adipose expression of 11β-HSD1 induced metabolic syndrome-like phenotypes in mice. Thus, 11β-HSD1 is a proposed therapeutic target to normalize glucocorticoid excess in a tissue-specific manner and mitigate obesity and insulin resistance. Selective inhibitors of 11β-HSD1 are under development for the treatment of type 2 diabetes and other components of the metabolic syndrome.

11beta-hydroxysteroid dehydrogenase activity in acromegalic patients with normal or impaired carbohydrate metabolism

The 11beta-hydroxysteroid dehydrogenase isoenzymes (11beta-HSD) catalyse the interconversion of cortisol (F) and cortisone (E). Earlier studies demonstrated that growth hormone (GH) and insulin resistance may exert opposite effects on the conversion of E to F by 11beta-HSD type 1. Therefore, in the present study we determined F and E concentrations in 562 plasma samples obtained from acromegalic patients during an active phase (76 patients) and after cure of the disease (68 patients). In addition, we examined whether type 2 diabetes mellitus or impaired glucose tolerance, which are frequently associated with active acromegaly could influence plasma F and E levels in these patients. We found that plasma F concentrations were similar in patients with active acromegaly and in those who were cured with pituitary surgery, irradiation and/or medical therapy (mean+/-S.E., 12.4+/-0.3 and 12.7+/-0.4 microg/dl, respectively). However, plasma E levels were significantly higher in patients with active compared to those with cured acromegaly (2.8+/-0.1 and 2.2+/-0.1 microg/dl, respectively; p<0.001), resulting in a lower F/E ratio in patients with active disease (4.6+/-0.1 vs. 5.9+/-0.2 in the cured group of patients; p<0.001). When the effect of altered carbohydrate homeostasis on plasma F and E was analysed, the results indicated significantly lower plasma E levels and higher F/E ratios in active acromegalic patients with type 2 diabetes mellitus or impaired glucose tolerance compared to those with normal carbohydrate metabolism (E, 2.5+/-0.1 and 3.0+/-0.1 microg/dl, respectively; F/E, 5.1+/-0.2 and 4.4+/-0.1; p<0.001), whereas plasma F concentrations were similar in these two groups (12.1+/-0.4 and 12.6+/-0.3 microg/dl, respectively). These findings indicate that disease activity exerts a significant impact on 11beta-HSD in acromegalic patients, which is further modified with altered carbohydrate homeostasis, frequently present in patients with active disease.

Overexpression of 11beta-hydroxysteroid dehydrogenase type 1 in hepatic and visceral adipose tissue is associated with metabolic disorders in morbidly obese patients

BACKGROUND

The enzyme 11-beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) catalyzes intracellular glucocorticoid reactivation by conversion of cortisone to cortisol in different tissues and have been implicated in several metabolic disorders associated with obesity. The aim of this study was to evaluate the 11beta-HSD1 expression in liver, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) in morbidly obese patients undergoing bariatric surgery and its correlations with clinical, anthropometric, and biochemical variables.

METHODS

A prospective study was conducted over a 27-month period. Hepatic, VAT, and SAT samples were obtained at the time of surgery. 11beta-HSD1 and 18S gene expression was measured using real-time quantitative reverse transcriptase-polymerase chain reaction.

RESULTS

Forty nine patients met the inclusion criteria [mean age: 42.2 +/- 10 years, body mass index (BMI): 42 +/- 6 kg/m(2), 71% women and 63% with metabolic syndrome (MS)]. 11beta-HSD1 mRNA levels were higher in liver than fat tissue (p < 0.001), being higher in SAT than in VAT (p < 0.001) without gender-specific differences. Hepatic expression of 11beta-HSD1 correlated positively with SAT and VAT, alanine aminotransferase (ALT), and serum glucose and was inversely associated with BMI. 11beta-HSD1 mRNA in VAT correlated positively with insulinemia, ALT, and LDL cholesterol. There were no associations between 11beta-HSD1 mRNA in SAT and the variables analyzed.

CONCLUSIONS

11beta-HSD1 expression is higher in liver in comparison to adipose tissue in obese patients. The observed correlations between hepatic and VAT 11beta-HSD1 expression with dyslipidemia and insulin resistance suggest that this enzyme might have a pathogenic role in obesity and related metabolic disorders.

Selective inhibition of 11beta-hydroxysteroid dehydrogenase 1 by 18alpha-glycyrrhetinic acid but not 18beta-glycyrrhetinic acid

Elevated cortisol concentrations have been associated with metabolic diseases such as diabetes type 2 and obesity. 11beta-hydroxysteroid dehydrogenase (11beta-HSD) type 1, catalyzing the conversion of inactive 11-ketoglucocorticoids into their active 11beta-hydroxy forms, plays an important role in the regulation of cortisol levels within specific tissues. The selective inhibition of 11beta-HSD1 is currently considered as promising therapeutic strategy for the treatment of metabolic diseases. In recent years, natural compound-derived drug design has gained considerable interest. 18beta-glycyrrhetinic acid (GA), a metabolite of the natural product glycyrrhizin, is not selective and inhibits both 11beta-HSD1 and 11beta-HSD2. Here, we compare the biological activity of 18beta-GA and its diastereomer 18alpha-GA against the two enzymes in lysates of transfected HEK-293 cells and show that 18alpha-GA selectively inhibits 11beta-HSD1 but not 11beta-HSD2. This is in contrast to 18beta-GA, which preferentially inhibits 11beta-HSD2. Using a pharmacophore model based on the crystal structure of the GA-derivative carbenoxolone in complex with human 11beta-HSD1, we provide an explanation for the differences in the activities of 18alpha-GA and 18beta-GA. This model will be used to design novel selective derivatives of GA.

Bis-aryl triazoles as selective inhibitors of 11beta-hydroxysteroid dehydrogenase type 1

3-Aryl-5-phenyl-(1,2,4)-triazoles were identified as selective inhibitors of 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1). They are active in both in vitro and an in vivo mouse pharmacodynamic (PD) model. The synthesis and structure activity relationships are presented.

Methionine restriction effects on 11 -HSD1 activity and lipogenic/lipolytic balance in F344 rat adipose tissue

Methionine restriction (MR) limits age-related adiposity in Fischer 344 (F344) rats. To assess the mechanism of adiposity resistance, the effect of MR on adipose tissue (AT) 11beta-hydroxysteroid dehydrogenase-1 (11beta-HSD1) was examined. MR induced 11beta-HSD1 activity in all ATs, correlating with increased tissue corticosterone. However, an inverse relationship between 11beta-HSD1 activity and adipocyte size was observed. Because dietary restriction controls lipogenic and lipolytic rates, MR's effects on lipogenic and lipolytic enzymes were evaluated. MR increased adipose triglyceride lipase and acetyl-coenzyme A carboxylase (ACC) protein levels but induced ACC phosphorylation at serine residues that render the enzyme inactive, suggesting alterations of basal lipolysis and lipogenesis. In contrast, no changes in basal or phosphorylated hormone-sensitive lipase levels were observed. ACC-phosphorylated sites were specific for AMP-activated protein kinase (AMPK); therefore, AMPK activation was evaluated. Significant differences in AMPKalpha protein, phosphorylation, and activity levels were observed only in retroperitoneal fat from MR rats. No differences in protein kinase A phosphorylation and intracellular cAMP levels were detected. In vitro studies revealed increased lipid degradation and a trend toward increased lipid synthesis, suggesting the presence of a futile cycle. In conclusion, MR disrupts the lipogenic/lipolytic balance, contributing importantly to adiposity resistance in F344 rats.

Evidence of altered cortisol metabolism in critically ill patients: a prospective study

CONTEXT

Changes in cortisol metabolism due to altered activity of the enzyme 11beta-hydroxysteroid dehydrogenase (11beta-HSD) have been implicated in the pathogenesis of hypertension, obesity and the metabolic syndrome. No published data exist on the activity of this enzyme in critical illness.

OBJECTIVE

To investigate cortisol metabolism in critically ill patients utilising plasma cortisol: cortisone ratio as an index of 11beta-HSD activity.

SETTING

Tertiary level intensive care unit.

PATIENTS

Three cohorts of critically ill patients: sepsis (n = 13); multitrauma (n = 20); and burns (n = 19).

MAIN OUTCOME MEASURES

Serial plasma cortisol: cortisone ratios.

MEASUREMENTS AND MAIN RESULTS

Plasma total cortisol cortisone ratios were determined serially after admission to the intensive care unit. As compared with controls, the plasma cortisol:cortisone ratio was significantly elevated in the sepsis and trauma cohorts on day 1 (22 +/- 9, p = 0.01, and 23 +/- 19, p = 0.0003, respectively) and remained elevated over the study period. Such a relationship was not demonstrable in burns. The ratio was significantly correlated with APACHE II (r = 0.77, p = 0.0008) and Simplified Acute Physiology Score (r = 0.7, p = 0.003) only on day 7 and only in the burns cohort. There were no significant correlations observed between total plasma cortisol or cortisone and sickness severity in the sepsis and trauma cohorts.

CONCLUSIONS

In critically ill patients, there is evidence of altered cortisol metabolism due to an increase in 11beta-HSD activity as demonstrated by an elevation of plasma cortisol: cortisone ratios. Further studies with larger sample sizes specifically designed to examine altered tissue 11beta-HSD activity and its clinical significance and correlation with outcome are warranted.

The protective role of exercise on stress system dysregulation and comorbidities

The human body, when under threat, elicits a set of neuroendocrine responses, including an increased secretion of glucocorticoids (GCs) and catecholamines from the adrenal gland and the activation of the sympathetic nervous system. These hormonal secretions allow a "fight or flight" response by mobilizing endogenous substrate and inducing a state of insulin resistance in the liver and skeletal muscles. Although the stress response was essential in ancient times to survive physical aggression, this threat has disappeared in our industrialized societies. However, in today's environment, the same stress responses can be elicited by emotional stimuli or professional and social stress. Such psychological stress may be protracted and unrelated to an increased metabolic demand. Thus, the energy mobilized is not used but is stored in visceral fat depots by the combined action of hypercortisolism and hyperinsulinemia. In addition, chronic activation of the stress system causes suppression of the gonadal, growth hormone (GH), and thyroid axes. These metabolic disturbances, in concert, lead to the clinical expression of a number of comorbidities including central obesity, hypertension, dyslipidemia, and endothelial dysfunction, all components of the metabolic syndrome and cardiometabolic risk factors. Moreover, chronic stress has deleterious effects on the brain and, in particular, affects hippocampal structure and function leading to cognitive and mood disturbances. Importantly, this stress-induced clinical phenotype is likely to be exaggerated in the presence of physical inactivity, resulting in a "stress-induced/exercise deficient" phenotype. Assuming that the stress response is a neuroendocrine mechanism that occurs in anticipation of physical action, then physical activity should be the natural means to prevent the consequences of stress. Indeed, accumulating evidence documents the beneficial effects of regular exercise in preventing or ameliorating the metabolic and psychological comorbidities induced by chronic stress. These benefits are thought to derive from a central effect of exercise to reduce the sensitivity to stress and also peripheral actions influencing metabolic functions and, in particular, insulin sensitivity and the partitioning of fuels toward oxidation rather than storage. It is concluded that chronic psychosocial stress, in the presence of physical inactivity, is likely to contribute to the epidemic of cardiometabolic and emotional disease of our current society. The way to prevent and combat this burden is by regular exercise.

The selectivity of tyrosine 280 of human 11β-hydroxysteroid dehydrogenase type 1 in inhibitor binding

11beta-Hydroxysteroid dehydrogenase type 1 is a homodimer where the carboxyl terminus of one subunit covers the active site of the dimer partner. Based on the crystal structure with CHAPS, the carboxyl terminal tyrosine 280 (Y280) has been postulated to interact with the substrate/inhibitor at the binding pocket of the dimer partner. However, the co-crystal structure with carbenoxolone argues against this role. To clarify and reconcile these findings, here we report our mutagenesis data and demonstrate that Y280 is not involved in substrate binding but rather plays a selective role in inhibitor binding. The involvement of Y280 in inhibitor binding depends on the inhibitor chemical structure. While Y280 is not involved in the binding of carbenoxolone, it is critical for the binding of glycyrrhetinic acid.

Active site variability of type 1 11beta-hydroxysteroid dehydrogenase revealed by selective inhibitors and cross-species comparisons

The NADPH-dependent enzyme type 1 11beta-hydroxysteroid dehydrogenase (11beta-HSD1) activates in a tissue-specific manner circulating pro-glucocorticoid hormones (cortisone in humans) to the 11beta-OH ligand (cortisol in humans), which is able to bind to its cognate receptor and regulate gene transcription. Modulation of this pre-receptor activation mechanism by selective enzyme inhibitors is a desirable goal in the treatment of insulin resistance and related metabolic disorders. Like most other hydroxysteroid dehydrogenases 11beta-HSD1 belongs to the evolutionarily conserved enzyme superfamily of short-chain dehydrogenases/reductases (SDR). The enzyme is anchored within the endoplasmic reticulum through an N-terminal transmembrane domain. In this study we aimed to characterize the active site of mammalian 11beta-HSD1 by determining primary structures from several mammalian lines (cat, hamster, cynomolgus, chimpanzee, dog) thus increasing substantially available sequence information, and allowing us to determine highly variable and constant parts within the primary structure. These regions were mapped to the recently determined three-dimensional structure and are mostly found around the substrate binding site. Furthermore we performed inhibition studies by using different series of inhibitors, comprising 11beta-HSD1 selective arylsulfonamidothiazoles and the unselective steroid-based compound carbenoxolone. The different arylsulfonamidothiazoles display distinct inhibition profiles versus the mammalian species tested, with several tight binding inhibitors for the human enzyme (Ki approximately 50 nM), intermediate for mouse, and weak or not binding inhibitors for rat and guinea pig (Ki>3 microM). Analysis of the inhibition mode reveals that the tight binding inhibitor BVT.528 is a competitive inhibitor for the human form, whereas the related compound BVT.2733 displays a mixed-type inhibition pattern versus the mouse enzyme. Taken together, this structure-activity study provides increased insight into active site complexity and catalytic mechanism of 11beta-HSD1, useful for further inhibitor design.

The role of tyrosine 177 in human 11beta-hydroxysteroid dehydrogenase type 1 in substrate and inhibitor binding: an unlikely hydrogen bond donor for the substrate

The catalytic motif (YSASK) at the active site of 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) is conserved across different species. The crystal structures of the human, guinea pig and mouse enzymes have been resolved to help identify the non-conserved residues at the active site. A tyrosine residue (Y177) upstream of the catalytic motif in human 11beta-HSD1 represents the largest difference at the active sites between the human and the rodent enzyme where the corresponding residue is glutamine. Although Y177 was postulated as a potential hydrogen bond donor in substrate binding in crystal structure-based modeling, no experimental evidence is available to support this notion. Here, we report that Y177 is not a hydrogen bond donor in substrate binding because removal of the hydroxyl group from its side chain by mutagenesis (Y177F) did not significantly change the Km value for cortisone. However, removal of the hydrophobic side chain by changing tyrosine to alanine (Y177A) or substitution with a hydrophilic side chain by changing tyrosine to glutamine (Y177Q) increased Km values for cortisone. These data suggest that Y177 is involved in substrate binding through its hydrophobic side chain but not by hydrogen bonding. In addition, the three mutations had little effect on the binding of the rodent substrate 11-dehydrocorticosterone, suggesting that Y177 does not confer substrate specificity. However, the same mutations reduced the affinity of the licorice derived 11beta-HSD1 inhibitor glycyrrhetinic acid by about 6- to 10-fold. Interestingly, the affinity of carbenoxolone, the hemisuccinate ester of glycyrrhetinic acid with a similar potency against the wildtype enzyme, was not drastically affected by the same mutations at Y177. These data suggest that Y177 has a unique role in inhibitor binding. Molecular modeling with glycyrrhetinic acid led to findings consistent with the experimental data and provided potential interaction mechanisms. Our data suggest that Y177 plays an important role in both substrate and inhibitor binding but it is unlikely a hydrogen bond donor for the substrate.

Adamantyl triazoles as selective inhibitors of 11β-hydroxysteroid dehydrogenase type 1

Adamantyl triazoles were identified as selective inhibitors of 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1). They are active both in in vitro and in in vivo pharmacodynamic models. The synthesis and structure-activity relationships of these inhibitors are presented.

The human mineralocorticoid receptor only partially differentiates between different ligands after expression in fission yeast

Cardiac failure is a major health problem with increasing incidence due to aging of the population. Studies in both experimental animals and humans have suggested that aldosterone excess may have deleterious effects on cardiac function. In order to generate a novel screening system for the identification of aldosterone antagonists, we expressed the human mineralocorticoid receptor (MR) and the human glucocorticoid receptor (GR), respectively, in the fission yeast Schizosaccharomyces pombe. Reporter plasmids containing two hormone-responsive elements upstream of a fission yeast minimal promotor and either a lacZ gene (for quantification) or a neomycin gene (for survival screening) were constructed and cotransformed into fission yeast strains with expression plasmids for MR or GR. The functionality of the reporter systems was then tested using physiological ligands of both receptors as well as known inhibitors. Transactivating activity of MR could be stimulated by aldosterone, 11-deoxycorticosterone, 11-deoxycortisol, cortisol, cortisone, and spironolactone, but not by progesterone, while GR activity was stimulated by cortisol and cortisone, but also not by progesterone. Taken together, we have succeeded in establishing fission yeast-based screening systems that allow the identification of MR- or GR-interacting compounds. Moreover, our data show that after expression in fission yeast both receptors did not differentiate between steroids with different configurations at positions 11beta, 17 and 18. This finding suggests that only recognition of C-21 substituents may be accomplished by the receptor proteins alone, while the physiologically important selectivity towards other positions of the steroid ligand depends on other factors which are not conserved from fission yeast to man.

The role of glucocorticoid action in the pathophysiology of the Metabolic Syndrome

Glucocorticoids are stress hormones that modulate a large number of physiological actions involved in metabolic, inflammatory, cardiovascular and behavioral processes. The molecular mechanisms and the physiological effects of glucocorticoids have been extensively studied. However, the involvement of glucocorticoid action in the etiology of the Metabolic Syndrome has not been well appreciated. Recently, accumulating clinical evidence and animal genetics studies have attracted growing interest in the role of glucocorticoid action in obesity and insulin resistance. This review will discuss the metabolic effects in the context of glucocorticoid metabolism and establish the association of glucocorticoid action with the features of the Metabolic Syndrome, especially obesity and insulin resistance. Special discussions will be focused on corticosteroid-binding globulin and 11beta-hydroxysteroid dehydrogenase type 1, two proteins that mediate glucocorticoid action and have been implicated in the Metabolic Syndrome. Due to the complexities of the glucocorticoid biology and the Metabolic Syndrome and limited space, this review is only intended to provide a general link between the two areas with broad rather than in-depth discussions of clinical, pharmacological and genetic findings.

Conformational Flexibility in Crystal Structures of Human 11β-Hydroxysteroid Dehydrogenase Type I Provide Insights into Glucocorticoid Interconversion and Enzyme Regulation

Human 11beta-hydroxysteroid dehydrogenase type I (11beta-HSD1) is an ER-localized membrane protein that catalyzes the interconversion of cortisone and cortisol. In adipose tissue, excessive cortisol production through 11beta-HSD1 activity has been implicated in the pathogenesis of type II diabetes and obesity. We report here biophysical, kinetic, mutagenesis, and structural data on two ternary complexes of 11beta-HSD1. The combined results reveal flexible active site interactions relevant to glucocorticoid recognition and demonstrate how four 11beta-HSD1 C termini converge to form an as yet uncharacterized tetramerization motif. A C-terminal Pro-Cys motif is localized at the center of the tetramer and forms reversible enzyme disulfides that alter enzyme activity. Conformational flexibility at the tetramerization interface is coupled to structural changes at the enzyme active site suggesting how the central Pro-Cys motif may regulate enzyme activity. Together, the crystallographic and biophysical data provide a structural framework for understanding 11beta-HSD1 activities and will ultimately facilitate the development of specific inhibitors.

Developments in Glucocorticoid Therapy

Recent evidence for a disease-modifying potential of low-dose glucocorticoids (GCs) in the treatment of rheumatoid arthritis has renewed the debate on the risk benefit ratio with this therapy. Two recent developments are described that might have a positive influence on these risk benefit ratios. One is the improvement in new GC compounds--designer GCs, alterations in bioactivity, and alterations in formulations. The other is a better understanding and management of the toxicity of GCs.

Inhibition of 17beta-hydroxysteroid dehydrogenases by phytoestrogens: comparison with other steroid metabolizing enzymes

Effects of phytoestrogens on human health have been reported for decades. These include not only beneficial action in cancer prevention but also endocrine disruption in males. Since then many molecular mechanisms underlying these effects have been identified. Targets of phytoestrogens comprise steroid receptors, steroid metabolising enzymes, elements of signal transduction and apoptosis pathways, and even the DNA processing machinery. Understanding the specific versus pleiotropic effects of selected phytoestrogens will be crucial for their biomedical application. This review will concentrate on the influence of phytoestrogens on 17beta-hydroxysteroid dehydrogenases from a comparative perspective with other steroid metabolizing enzymes.

A novel 18 beta-glycyrrhetinic acid analogue as a potent and selective inhibitor of 11 beta-hydroxysteroid dehydrogenase 2

Using 18beta-glycyrrhetinic acid as a template, the synthesis of a series of secondary amides at the 30-position is described and the effects of these modifications on the SAR of the 11beta-hydroxysteroid dehydrogenase isozymes type 1 and 2 from the rat are investigated. An isoform selective inhibitor has been discovered and compound 5, N-(2-hydroxyethyl)-3beta-hydroxy-11-oxo-18beta-olean-12-en-30-oic acid amide, is highlighted as a very potent and selective inhibitor of 11beta-hydroxysteroid dehydrogenase 2 with an IC(50)=4 pM.

On the mechanism of mitochondrial permeability transition induction by glycyrrhetinic acid

Glycyrrhetinic acid (GE), the aglycone of glycyrrhizic acid, a triterpene glycoside which represents one of the main constituents of licorice root, induces an oxidative stress in liver mitochondria responsible for the induction of membrane permeability transition. In fact, GE, by interacting with the mitochondrial respiratory chain, generates hydrogen peroxide which in turn oxidizes critical thiol groups and endogenous pyridine nucleotides leading to the opening of the transition pore. Most likely the reactive group of GE is the carbonyl oxygen in C-11 which, by interacting mainly with a Fe/S centre of mitochondrial complex I, generates an oxygen-centered radical responsible for the pro-oxidant action.

Hormones and immune function: implications of aging

Aging is associated with a decline in immunity described as immunosenescence. This is paralleled by a decline in the production of several hormones, as typically illustrated by the menopausal loss of ovarian oestrogen production. However, other hormonal changes that occur with aging and that potentially impact on immune function include the release of the pineal gland hormone melatonin and pituitary growth hormone, adrenal production of dehydroepiandrosterone and tissue-specific availability of active vitamin D. It remains to be established whether hormonal changes with aging actually contribute to immunosenescence and this area is at the interface of fact and fiction, clearly inviting systematic research efforts. As a step in this direction, the present review summarizes established facts on the physiology of secretion and function of hormones that, in most cases, decline with aging and that are likely to affect the immune system.

Novel 18β-glycyrrhetinic acid analogues as potent and selective inhibitors of 11β-hydroxysteroid dehydrogenases

Extensive structural modifications to the 18beta-glycyrrhetinic acid template are described and their effects on the SAR of the 11beta-hydroxysteroid dehydrogenase isozymes type 1 and 2 from the rat are investigated. Isoform selective inhibitors have been discovered and compound 7 N-(2-hydroxyethyl)-3beta-hydroxy-11-oxo-18beta-olean-12-en-30-oic acid amide is highlighted as a very potent selective inhibitor of 11beta-hydroxysteroid dehydrogenase 2 with an IC(50) = 4pM.

Secondary forms of polycystic ovary syndrome

Hyperandrogenism and chronic anovulation are the most common endocrine disorders of premenopausal women. Most patients have polycystic ovary syndrome (PCOS), which is essentially benign, but might be associated with increased cardiovascular morbidity; PCOS is associated with specific endocrine and ultrasonographic features. Some patients exhibiting similar features to PCOS might have other underlying diagnoses, such as adrenal and ovarian steroidogenic deficiencies, adrenal and ovarian androgen-secreting tumours, other medical or endocrine disorders, and/or be on medications thought to cause PCOS, such as anti-epileptics. Unlike PCOS, some of these conditions can occasionally be life threatening and require prompt diagnosis and treatment. Here, we focus on these disorders, including their pathogenesis, and attempt to define the clinical and biochemical features that distinguish them from PCOS.

The role of 17 beta-hydroxysteroid dehydrogenases

The biological activity of steroid hormones is regulated at the pre-receptor level by several enzymes including 17 beta-hydroxysteroid dehydrogenases (17 beta -HSD). The latter are present in many microorganisms, invertebrates and vertebrates. Dysfunctions in human 17 beta-hydroxysteroid dehydrogenases result in disorders of biology of reproduction and neuronal diseases, the enzymes are also involved in the pathogenesis of various cancers. 17 beta-hydroxysteroid dehydrogenases reveal a remarkable multifunctionality being able to modulate concentrations not only of steroids but as well of fatty and bile acids. Current knowledge on genetics, biochemistry and medical implications is presented in this review.