Selective inhibitors of 11beta-hydroxysteroid dehydrogenase type 1 for patients with metabolic syndrome: is the target liver, fat, or both?

Safety, tolerability, pharmacodynamics and pharmacokinetics following once-daily doses of BI 187004, an inhibitor of 11 beta-hydroxysteroid dehydrogenase-1, over 28 days in patients with type 2 diabetes mellitus and overweight or obesity

AIMS

To study the oral 11 beta-hydroxysteroid dehydrogenase-1 (11β-HSD1) inhibitor BI 187004 (NCT02150824), as monotherapy and in combination with metformin, versus placebo in patients with type 2 diabetes mellitus (T2DM) affected by overweight or obesity.

MATERIALS AND METHODS

This Phase II, randomized controlled trial investigated multiple rising doses of BI 187004 as monotherapy (Arm 1: 20, 80 or 240 mg) and in combination with metformin (Arm 2: 240 mg), in adults with T2DM and a body mass index of 28-40 kg/m² .

RESULTS

In total, 103 patients (Arm 1: n = 62, Arm 2: n = 41) were included in this study. BI 187004 was rapidly absorbed and exposure increased approximately dose-dependently. Target engagement of 11β-HSD1 was observed with near-full inhibition of 11β-HSD1 in the liver [decreased (5α-tetrahydrocortisol + 5β-tetrahydrocortisol)/tetrahydrocortisone ratio]; hypothalamic-pituitary-adrenal axis activation was also seen (increased total urinary corticosteroids). No clinically relevant changes from baseline with BI 187004 treatment were observed for bodyweight or meal tolerance test parameters, or in most efficacy endpoints testing glucose and lipid metabolism; a significant increase was observed in weighted mean plasma glucose (p < .05 for 80 and 240 mg BI 187004) but not fasting plasma glucose. Drug-related adverse events were reported for 14 patients (22.6%) in Arm 1 and 10 patients (24.4%) in Arm 2, most frequently headache, diarrhoea, flushing and dizziness. A dose-dependent increase in heart rate was seen with BI 187004 treatment.

CONCLUSIONS

BI 187004 was generally well tolerated in patients with T2DM. Despite complete 11β-HSD1 inhibition, no clinically relevant effects were observed with BI 187004.

Selective Inhibition of 11beta-Hydroxysteroiddehydrogenase-1 with BI 187004 in Patients with Type 2 Diabetes and Overweight or Obesity: Safety, Pharmacokinetics, and Pharmacodynamics After Multiple Dosing Over 14 Days

OBJECTIVE

To assess safety, tolerability, pharmacokinetics, and pharmacodynamics of treatment with the selective 11beta-hydroxysteroid dehydrogenase-1 (11beta-HSD1) inhibitor BI 187004 in male and female patients with type 2 diabetes and overweight or obesity.

METHODS

Randomized, double-blind, parallel-group, placebo-controlled multiple rising dose study, with 10-360 mg BI 187004 once daily over 14 days in 71 patients. Assessments included 11beta-HSD1 inhibition in the liver and subcutaneous adipose tissue ex vivo (clinical trial registry number NCT01874483).

RESULTS

BI 187004 was well tolerated and safe in all tested dose groups. The incidence of drug-related adverse events was 51.8% (n=29) for BI 187004 and 35.7% (n=5) for placebo. There were no clinically relevant deviations in laboratory or electrocardiogram parameters besides one patient on 360 mg discontinuing treatment due to moderate supraventricular tachycardia.BI 187004 was rapidly absorbed within 2 h; exposure increased non-proportionally. The oral clearance was low, apparent volume of distribution was moderate to large, and terminal half-life with 106-124 h was rather long. Urinary tetrahydrocortisol/tetrahydrocortisone ratio decreased, indicating liver 11beta-HSD1 inhibition. Median inhibition of 11beta-HSD1 in subcutaneous adipose tissue biopsies was 87.9-99.4% immediately after the second dose and 73.8-97.5% 24 h after the last dose of BI 187004.

CONCLUSIONS

BI 187004 was safe and well tolerated over 14 days and could be dosed once daily. Targeted 11beta-HSD1 enzyme inhibition of≥80% could be shown for BI 187004 doses≥40 mg. This dose should be targeted in further studies to test blood glucose lowering in patients with type 2 diabetes and overweight or obesity.

Structural Insights and Docking Analysis of Adamantane-Linked 1,2,4-Triazole Derivatives as Potential 11β-HSD1 Inhibitors

The solid-state structural analysis and docking studies of three adamantane-linked 1,2,4-triazole derivatives are presented. Crystal structure analyses revealed that compound 2 crystallizes in the triclinic P-1 space group, while compounds 1 and 3 crystallize in the same monoclinic P21/c space group. Since the only difference between them is the para substitution on the aryl group, the electronic nature of these NO2 and halogen groups seems to have no influence over the formation of the solid. However, a probable correlation with the size of the groups is not discarded due to the similar intermolecular disposition between the NO2/Cl substituted molecules. Despite the similarities, CE-B3LYP energy model calculations show that pairwise interaction energies vary between them, and therefore the total packing energy is affected. HOMO-LUMO calculated energies show that the NO2 group influences the reactivity properties characterizing the molecule as soft and with the best disposition to accept electrons. Further, in silico studies predicted that the compounds might be able to inhibit the 11β-HSD1 enzyme, which is implicated in obesity and diabetes. Self- and cross-docking experiments revealed that a number of non-native 11β-HSD1 inhibitors were able to accurately dock within the 11β-HSD1 X-ray structure 4C7J. The molecular docking of the adamantane-linked 1,2,4-triazoles have similar predicted binding affinity scores compared to the 4C7J native ligand 4YQ. However, they were unable to form interactions with key active site residues. Based on these docking results, a series of potentially improved compounds were designed using computer aided drug design tools. The docking results of the new compounds showed similar predicted 11β-HSD1 binding affinity scores as well as interactions to a known potent 11β-HSD1 inhibitor.

Safety, tolerability, pharmacokinetics and pharmacodynamics of single oral doses of BI 187004, an inhibitor of 11beta-hydroxysteroid dehydrogenase-1, in healthy male volunteers with overweight or obesity

BACKGROUND

The study characterizes safety, tolerability, pharmacokinetic and pharmacodynamic profiles of single rising doses of the 11beta-hydroxysteroid dehydrogenase-1 (11beta-HSD1) inhibitor BI 187004 in healthy men with overweight or obesity.

METHODS

This was a randomized, double-blind, parallel group, placebo-controlled study with administration of 2.5-360 mg BI 187004 or placebo once daily as single dose in 72 healthy male volunteers with overweight or obesity. Assessments included 11beta-HSD1 inhibition in the liver (assessed indirectly by urinary tetrahydrocortisol/tetrahydrocortisone ratio) and in subcutaneous adipose tissue ex vivo and determination of hypothalamus-pituitary-adrenal axis hormones.

RESULTS

BI 187004 was well tolerated and safe in all tested dose groups. The incidence of drug-related adverse events was 16.7% (n = 9) for all 9 BI 187004 dose groups and 5.9% (n = 1) for placebo. All treatment groups were similar concerning kind and intensity of adverse events. No clinically relevant deviations in clinical laboratory or ECG parameters were reported. Exposure of BI 187004 increased non-proportionally over the entire dose range tested. The geometric mean apparent terminal half-life decreased from 33.5 h (5 mg) to 14.5 h (160 mg) remaining stable up to 360 mg. Renal excretion of BI 187004 was low (3-5%). Urinary tetrahydrocortisol/tetrahydrocortisone ratio decreased, indicating liver 11beta-HSD1 inhibition. Median inhibition of 11beta-HSD1 in subcutaneous adipose tissue biopsies following single dosing ranged from 86.8% (10 mg) to 99.5% (360 mg) after 10 h and from 59.4% (10 mg) to 98.6% (360 mg) after 24 h.

CONCLUSIONS

BI 187004 as single dose was safe and well tolerated and is suitable for once daily dosing. There was significant, sustained 11beta-HSD1 inhibition in liver and adipose tissue.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01587417 , registered on 26-Apr-2012.

A Recent Achievement In the Discovery and Development of Novel Targets for the Treatment of Type-2 Diabetes Mellitus

Type 2 diabetes (T2DM) is a chronic metabolic disorder. Impaired insulin secretion, enhanced hepatic glucose production, and suppressed peripheral glucose use are the main defects responsible for developing the disease. Besides, the pathophysiology of T2DM also includes enhanced glucagon secretion, decreased incretin secretion, increased renal glucose reabsorption, and adipocyte, and brain insulin resistance. The increasing prevalence of T2DM in the world beseeches an urgent need for better treatment options. The antidiabetic drugs focus on control of blood glucose concentration, but the future treatment goal is to delay disease progression and treatment failure, which causes poorer glycemic regulation. Recent treatment approaches target on several novel pathophysiological defects present in T2DM. Some of the promising novel targets being under clinical development include those that increase insulin sensitization (antagonists of glucocorticoids receptor), decreasing hepatic glucose production (glucagon receptor antagonist, inhibitors of glycogen phosphorylase and fructose-1,6-biphosphatase). This review summarizes studies that are available on novel targets being studied to treat T2DM with an emphasis on the small molecule drug design. The experience gathered from earlier studies and knowledge of T2DM pathways can guide the anti-diabetic drug development toward the discovery of drugs essential to treat T2DM.

Crystal structure, Hirshfeld surface analysis and DFT studies of 5-(adamantan-1-yl)-3-[(4-chlorobenzyl)sulfanyl]-4-methyl-4H-1,2,4-triazole, a potential 11β-HSD1 inhibitor

5-(Adamantan-1-yl)-3-[(4-chlorobenzyl)sulfanyl]-4-methyl-4H-1,2,4-triazole (4) was identified as a potential 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitor and this paper describes the in-depth structural analysis thereof. Compound 4 was synthesized in a 92% yield and its 3D-structure confirmed by single-crystal X-ray diffraction. Hirshfeld surface analysis indicated that H^…H, C-H^…C, C-H^…Cl and especially C-H^…N hydrogen bond interactions are the primary contributors to the intermolecular stabilisation in the crystal. In order to explore the properties of 4, free from the influence of the crystal field, density functional theory (DFT) calculations were conducted. Results indicated that the DFT optimized geometry of 4 produced a conformer (4a) that is significantly different from the crystal structure. Further experiments confirmed that the crystal structure is not the absolute minimum conformation. This indicated that the crystal packing forces has significantly influenced the conformation thereof. Frontier molecular orbital energies and net atomic charges were also calculated to elucidate the electronic properties of 4a. These results provided insight into areas of the molecule that may present with the ability to form binding interactions at the 11β-HSD1 active site. Molecular docking experiments revealed important intermolecular interactions between 4a and 11β-HSD1. These results indicate that 4 may be considered for further drug design endeavors.

Copeptin and insulin resistance: effect modification by age and 11 β-HSD2 activity in a population-based study

PURPOSE

Arginine vasopressin (AVP) may be involved in metabolic syndrome (MetS) by altering liver glycogenolysis, insulin and glucagon secretion, and pituitary ACTH release. Moreover, AVP stimulates the expression of 11β-hydroxysteroid-dehydrogenase-type 2 (11β-HSD2) in mineralocorticosteroid cells. We explored whether apparent 11β-HSD2 activity, estimated using urinary cortisol-to-cortisone ratio, modulates the association between plasma copeptin, as AVP surrogate, and insulin resistance/MetS in the general adult population.

METHODS

This was a multicentric, family-based, cross-sectional sample of 1089 subjects, aged 18-90 years, 47% men, 13.4% MetS, in Switzerland. Mixed multivariable linear and logistic regression models were built to investigate the association of insulin resistance (HOMA-IR)/fasting glucose and MetS/Type 2 Diabetes with copeptin, while considering potential confounders or effect modifiers into account. Stratified results by age and 11β-HSD2 activity were presented as appropriate.

RESULTS

Plasma copeptin was higher in men [median 5.2, IQR (3.7-7.8) pmol/L] than in women [median 3.0, IQR (2.2-4.3) pmol/L], P < 0.0001. HOMA-IR was positively associated with copeptin after full adjustment if 11β-HSD2 activity was high [β (95% CI) = 0.32 (0.17-0.46), P < 0.001] or if age was high [β (95% CI) = 0.34 (0.20-0.48), P < 0.001], but not if either 11β-HSD2 activity or age was low. There was a positive association of type 2 diabetes with copeptin [OR (95% CI) = 2.07 (1.10-3.89), P = 0.024), but not for MetS (OR (95% CI) = 1.12 (0.74-1.69), P = 0.605), after full adjustment.

CONCLUSIONS

Our data suggest that age and apparent 11β-HSD2 activity modulate the association of copeptin with insulin resistance at the population level but not MeTS or diabetes. Further research is needed to corroborate these results and to understand the mechanisms underlying these findings.

Comparison of flavonoids and isoflavonoids to inhibit rat and human 11β-hydroxysteroid dehydrogenase 1 and 2

Many flavonoids and isoflavonoids have anti-diabetic effects in animal models. However, the mechanisms that are involved are generally unclear. Since 11β-hydroxysteroid dehydrogenases (HSD11Bs) play important roles in diabetes, we hypothesize that flavonoids and isoflavonoids may affect diabetes by targeting two isoforms of HSD11B differently. The inhibitory effects of flavonoids (apigenin and quercetin) and isoflavonoids [genistein and (±) equol] on rat and human HSD11B1 and HSD11B2 were analyzed. The potencies of inhibition on human HSD11B1 reductase was in the order of apigenin > quercetin > genistein > (±) equol, with IC₅₀ values of 2.19, 5.36, 11.00, and over 100 μM, respectively. Genistein also inhibited rat HSD11B1 reductase with IC₅₀ value of 24.58 μM, while other three chemicals showed no effects on the enzyme activity with IC₅₀ values over 100 μM. However, apigenin and (±) equol did not inhibit human HSD11B2 at concentrations as high as 100 μM, while genistein and quercetin inhibited human HSD11B2 by 60% and 50% at 100 μM, respectively. The effective flavonoids and isoflavonoids are noncompetitive inhibitors of HSD11B1 when steroid substrates were used. Docking analysis showed that they bound to the steroid-binding site of the human HSD11B1. These data indicate that apigenin is a selective inhibitor of human HSD11B1 of two HSD11B isoforms, which may be useful in managing symptoms of the metabolic syndrome.

Inhibition of 11β-HSD1 by LG13 improves glucose metabolism in type 2 diabetic mice

11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) controls the production of active glucocorticoid (GC) and has been proposed as a new target for the treatment of type 2 diabetes. We have previously reported that a natural product, curcumin, exhibited moderate inhibition and selectivity on 11β-HSD1. By analyzing the models of protein, microsome, cells and GCs-induced mice in vitro and in vivo, this study presented a novel curcumin analog, LG13, as a potent selective 11β-HSD1 inhibitor. In vivo, Type 2 diabetic mice were treated with LG13 for 42 days to assess the pharmacological benefits of 11β-HSD1 inhibitor on hepatic glucose metabolism. In vitro studies revealed that LG13 selectively inhibited 11β-HSD1 with IC50 values at nanomolar level and high selectivity over 11β-HSD2. Targeting 11β-HSD1, LG13 could inhibit prednisone-induced adverse changes in mice, but had no effects on dexamethasone-induced ones. Further, the 11β-HSD1 inhibitors also suppressed 11β-HSD1 and GR expression, indicating a possible positive feedback system in the 11β-HSD1/GR cycle. In type 2 diabetic mice induced by high fat diet plus low-dosage STZ injection, oral administration with LG13 for 6 weeks significantly decreased fasting blood glucose, hepatic glucose metabolism, structural disorders, and lipid deposits. LG13 exhibited better pharmacological effects in vivo than insulin sensitizer pioglitazone and potential 11β-HSD1 inhibitor PF-915275. These pharmacological and mechanistic insights on LG13 also provide us novel agents, leading structures, and strategy for the development of 11β-HSD1 inhibitors treating metabolic syndromes.

11β-HSD1 modulates LPS-induced innate immune responses in adipocytes by altering expression of PTEN

Inhibition of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) represents a therapeutic target for treating hyperglycemia in type 2 diabetes. Here, we investigate the effects of 11β-HSD1 on the innate immune response of adipocytes to produce proinflammatory cytokines. The 11β-HSD1 inhibitor emodin, or 11β-HSD1-targeted small interfering RNA, dose dependently suppressed IL-6, IL-1β, and TNF-α expression in lipopolysaccharide-treated 3T3-L1 adipocytes. Inhibiting 11β-HSD1 also reduced phosphatase and tensin homologue (PTEN) expression, a negative regulator of phosphatidylinositol 3-kinase effects, whereas 1pM cortisone or dexamethasone induced IL-6 and PTEN levels. PTEN-targeted small interfering RNA decreased IL-6, IL-1β, and TNF-α without affecting 11β-HSD1 levels. Correspondingly, emodin increased phosphorylated protein kinase B (p-PKB) (Ser473) to PKB ratio but not p-PKB (Thr308) to PKB ratio. Emodin did not increase the p-PKB (Ser473) to PKB ratio when the rapamycin-insensitive companion of mTOR was depleted, further supporting the involvement of mammalian target of rapamycin complex 2 in PKB phosphorylation. Moreover, emodin suppressed phosphorylated inhibitor of κB α (p-IκBα) to IκBα ratio and reduced nuclear factor κ B subunit p50 in the nuclear fraction. In contrast, 1pM cortisone or dexamethasone decreased p-PKB (Ser473) to PKB ratio, increased p-IκBα to IκBα ratio, and increased nuclear NF-κB subunit p50. Additionally, wortmannin had similar effects on IL-6, p-PKB (Ser473) to PKB ratio, and p-IκBα to IκBα ratio as 1pM cortisone or dexamethasone. Finally, emodin treatment of streptozotocin diabetic rats on a high-fat diet reduced levels of IL-6, PTEN, Cluster of Differentiation 68, and the ratio of p-IκBα to IκBα in visceral fat, indicating that our findings in vitro may also apply to visceral fat in vivo. Together, these results suggest that inhibiting 11β-HSD1 reduces lipopolysaccharide-induced proinflammatory innate immune responses in adipocytes by down-regulating PTEN expression, leading to activation of the PI3K/PKB pathway.

Mechanisms of glucocorticoid-induced insulin resistance: focus on adipose tissue function and lipid metabolism

Glucocorticoids (GCs) are critical in the regulation of the stress response, inflammation and energy homeostasis. Excessive GC exposure results in whole-body insulin resistance, obesity, cardiovascular disease, and ultimately decreased survival, despite their potent anti-inflammatory effects. This apparent paradox may be explained by the complex actions of GCs on adipose tissue functionality. The wide prevalence of oral GC therapy makes their adverse systemic effects an important yet incompletely understood clinical problem. This article reviews the mechanisms by which supraphysiologic GC exposure promotes insulin resistance, focusing in particular on the effects on adipose tissue function and lipid metabolism.

Dehydroepiandrosterone exerts antiglucocorticoid action on human preadipocyte proliferation, differentiation, and glucose uptake

Glucocorticoids increase adipocyte proliferation and differentiation, a process underpinned by the local reactivation of inactive cortisone to active cortisol within adipocytes catalyzed by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). The adrenal sex steroid precursor dehydroepiandrosterone (DHEA) has been shown to inhibit 11β-HSD1 in murine adipocytes; however, rodent adrenals do not produce DHEA physiologically. Here, we aimed to determine the effects and underlying mechanisms of the potential antiglucocorticoid action of DHEA and its sulfate ester DHEAS in human preadipocytes. Utilizing a human subcutaneous preadipocyte cell line, Chub-S7, we examined the metabolism and effects of DHEA in human adipocytes, including adipocyte proliferation, differentiation, 11β-HSD1 expression, and activity and glucose uptake. DHEA, but not DHEAS, significantly inhibited preadipocyte proliferation via cell cycle arrest in the G1 phase independent of sex steroid and glucocorticoid receptor activation. 11β-HSD1 oxoreductase activity in differentiated adipocytes was inhibited by DHEA. DHEA coincubated with cortisone significantly inhibited preadipocyte differentiation, which was assessed by the expression of markers of early (LPL) and terminal (G3PDH) adipocyte differentiation. Coincubation with cortisol, negating the requirement for 11β-HSD1 oxoreductase activity, diminished the inhibitory effect of DHEA. Further consistent with glucocorticoid-opposing effects of DHEA, insulin-independent glucose uptake was significantly enhanced by DHEA treatment. DHEA increases basal glucose uptake and inhibits human preadipocyte proliferation and differentiation, thereby exerting an antiglucocorticoid action. DHEA inhibition of the amplification of glucocorticoid action mediated by 11β-HSD1 contributes to the inhibitory effect of DHEA on human preadipocyte differentiation.

Curcumin as a potent and selective inhibitor of 11β-hydroxysteroid dehydrogenase 1: improving lipid profiles in high-fat-diet-treated rats

Background

11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) activates glucocorticoid locally in liver and fat tissues to aggravate metabolic syndrome. 11β-HSD1 selective inhibitor can be used to treat metabolic syndrome. Curcumin and its derivatives as selective inhibitors of 11β-HSD1 have not been reported.

Methodology

Curcumin and its 12 derivatives were tested for their potencies of inhibitory effects on human and rat 11β-HSD1 with selectivity against 11β-HSD2. 200 mg/kg curcumin was gavaged to adult male Sprague-Dawley rats with high-fat-diet-induced metabolic syndrome for 2 months.

Results and Conclusions

Curcumin exhibited inhibitory potency against human and rat 11β-HSD1 in intact cells with IC₅₀ values of 2.29 and 5.79 µM, respectively, with selectivity against 11β-HSD2 (IC₅₀, 14.56 and 11.92 µM). Curcumin was a competitive inhibitor of human and rat 11β-HSD1. Curcumin reduced serum glucose, cholesterol, triglyceride, low density lipoprotein levels in high-fat-diet-induced obese rats. Four curcumin derivatives had much higher potencies for Inhibition of 11β-HSD1. One of them is (1E,4E)-1,5-bis(thiophen-2-yl) penta-1,4-dien-3-one (compound 6), which had IC₅₀ values of 93 and 184 nM for human and rat 11β-HSD1, respectively. Compound 6 did not inhibit human and rat kidney 11β-HSD2 at 100 µM. In conclusion, curcumin is effective for the treatment of metabolic syndrome and four novel curcumin derivatives had high potencies for inhibition of human 11β-HSD1 with selectivity against 11β-HSD2.

Essential roles of 11β-HSD1 in regulating brown adipocyte function

Brown adipose tissue (BAT) increases energy expenditure and is an attractive therapeutic target for obesity. 11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1), an amplifier of local glucocorticoid activity, has been shown to modulate white adipose tissue (WAT) metabolism and function. In this study, we investigated the roles of 11β-HSD1 in regulating BAT function. We observed a significant increase in the expression of BAT-specific genes, including UCP1, Cidea, Cox7a1, and Cox8b, in BVT.2733 (a selective inhibitor of 11β-HSD1)-treated and 11β-HSD1-deficient primary brown adipocytes of mice. By contrast, a remarkable decrease in BAT-specific gene expression was detected in brown adipocytes when 11β-HSD1 was overexpressed, which effect was reversed by BVT.2733 treatment. Consistent with the in vitro results, expression of a range of genes related to brown fat function in high-fat diet-fed mice treated with BVT.2733. Our results indicate that 11β-HSD1 acts as a vital regulator that controls the expression of genes related to brown fat function and as such may become a potential target in preventing obesity.

11β-Hydroxysteroid dehydrogenase type 1: relevance of its modulation in the pathophysiology of obesity, the metabolic syndrome and type 2 diabetes mellitus

Recent evidence strongly argues for a pathogenic role of glucocorticoids and 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) in obesity and the metabolic syndrome, a cluster of risk factors for atherosclerotic cardiovascular disease and type 2 diabetes mellitus (T2DM) that includes insulin resistance (IR), dyslipidaemia, hypertension and visceral obesity. This has been partially prompted not only by the striking clinical resemblances between the metabolic syndrome and Cushing's syndrome (a state characterized by hypercortisolism that associates with metabolic syndrome components) but also from monogenic rodent models for the metabolic syndrome (e.g. the leptin-deficient ob/ob mouse or the leptin-resistant Zucker rat) that display overall increased secretion of glucocorticoids. However, systemic circulating glucocorticoids are not elevated in obese patients and/or patients with metabolic syndrome. The study of the role of 11β-HSD system shed light on this conundrum, showing that local glucocorticoids are finely regulated in a tissue-specific manner at the pre-receptor level. The system comprises two microsomal enzymes that either activate cortisone to cortisol (11β-HSD1) or inactivate cortisol to cortisone (11β-HSD2). Transgenic rodent models, knockout (KO) for HSD11B1 or with HSD11B1 or HSD11B2 overexpression, specifically targeted to the liver or adipose tissue, have been developed and helped unravel the currently undisputable role of the enzymes in metabolic syndrome pathophysiology, in each of its isolated components and in their prevention. In the transgenic HSD11B1 overexpressing models, different features of the metabolic syndrome and obesity are replicated. HSD11B1 gene deficiency or HSD11B2 gene overexpression associates with improvements in the metabolic profile. In face of these demonstrations, research efforts are now being turned both into the inhibition of 11β-HSD1 as a possible pharmacological target and into the role of dietary habits on the establishment or the prevention of the metabolic syndrome, obesity and T2DM through 11β-HSD1 modulation. We intend to review and discuss 11β-HSD1 and obesity, the metabolic syndrome and T2DM and to highlight the potential of its inhibition for therapeutic or prophylactic approaches in those metabolic diseases.

BVT.2733, a selective 11β-hydroxysteroid dehydrogenase type 1 inhibitor, attenuates obesity and inflammation in diet-induced obese mice

BACKGROUND

Inhibition of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) is being pursued as a new therapeutic approach for the treatment of obesity and metabolic syndrome. Therefore, there is an urgent need to determine the effect of 11β-HSD1 inhibitor, which suppresses glucocorticoid action, on adipose tissue inflammation. The purpose of the present study was to examine the effect of BVT.2733, a selective 11β-HSD1 inhibitor, on expression of pro-inflammatory mediators and macrophage infiltration in adipose tissue in C57BL/6J mice.

METHODOLOGY/PRINCIPAL FINDINGS

C57BL/6J mice were fed with a normal chow diet (NC) or high fat diet (HFD). HFD treated mice were then administrated with BVT.2733 (HFD+BVT) or vehicle (HFD) for four weeks. Mice receiving BVT.2733 treatment exhibited decreased body weight and enhanced glucose tolerance and insulin sensitivity compared to control mice. BVT.2733 also down-regulated the expression of inflammation-related genes including monocyte chemoattractant protein 1 (MCP-1), tumor necrosis factor alpha (TNF-α) and the number of infiltrated macrophages within the adipose tissue in vivo. Pharmacological inhibition of 11β-HSD1 and RNA interference against 11β-HSD1 reduced the mRNA levels of MCP-1 and interleukin-6 (IL-6) in cultured J774A.1 macrophages and 3T3-L1 preadipocyte in vitro.

CONCLUSIONS/SIGNIFICANCE

These results suggest that BVT.2733 treatment could not only decrease body weight and improve metabolic homeostasis, but also suppress the inflammation of adipose tissue in diet-induced obese mice. 11β-HSD1 may be a very promising therapeutic target for obesity and associated disease.

Discovery of 3-hydroxy-4-cyano-isoquinolines as novel, potent, and selective inhibitors of human 11β-hydroxydehydrogenase 1 (11β-HSD1)

Derived from the HTS hit 1, a series of hydroxyisoquinolines was discovered as potent and selective 11β-HSD1 inhibitors with good cross species activity. Optimization of substituents at the 1 and 4 positions of the isoquinoline group in addition to the core modifications, with a special focus on enhancing metabolic stability and aqueous solubility, resulted in the identification of several compounds as potent advanced leads.

11β-hydroxysteroid dehydrogenases and the brain: from zero to hero, a decade of progress

Glucocorticoids have profound effects on brain development and adult CNS function. Excess or insufficient glucocorticoids cause myriad abnormalities from development to ageing. The actions of glucocorticoids within cells are determined not only by blood steroid levels and target cell receptor density, but also by intracellular metabolism by 11β-hydroxysteroid dehydrogenases (11β-HSD). 11β-HSD1 regenerates active glucocorticoids from their inactive 11-keto derivatives and is widely expressed throughout the adult CNS. Elevated hippocampal and neocortical 11β-HSD1 is observed with ageing and causes cognitive decline; its deficiency prevents the emergence of cognitive defects with age. Conversely, 11β-HSD2 is a dehydrogenase, inactivating glucocorticoids. The major central effects of 11β-HSD2 occur in development, as expression of 11β-HSD2 is high in fetal brain and placenta. Deficient feto-placental 11β-HSD2 results in a life-long phenotype of anxiety and cardiometabolic disorders, consistent with early life glucocorticoid programming.

Adipose tissue-targeted 11β-hydroxysteroid dehydrogenase type 1 inhibitor protects against diet-induced obesity

Current pharmacological treatments for obesity and metabolic syndrome have various limitations. Recently, adipose tissue 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) has been proposed as a novel therapeutic target for the treatment of obesity and metabolic syndrome. Nevertheless, there is no adipose tissue-targeted 11β-HSD1 inhibitor available now. We sought to develop a new 11β-HSD1 pharmacological inhibitor that homes specifically to the white adipose tissue and aimed to investigate whether adipose tissue-targeted 11β-HSD1 inhibitor might decrease body weight gain and improve glucose tolerance in diet-induced obesity mice. BVT.2733, an 11β-HSD1 selective inhibitor was connected with a peptide CKGGRAKDC that homes to white fat vasculature. CKGGRAKDC-BVT.2733 (T-BVT) or an equimolar mixture of CKGGRAKDC and BVT.2733 (NT-BVT) was given to diet-induced obesity mice for two weeks through subcutaneous injection. T-BVT decreased body weight gain, improved glucose tolerance and decreased adipocyte size compared with vehicle treated mice. In adipose tissue T-BVT administration significantly increased adiponectin, vaspin mRNA levels; In liver T-BVT administration decreased the mRNA level of phosphoenolpyruvate carboxykinase (PEPCK), increased the mRNA levels of mitochondrial carnitine palmi-toyltransferase-I (mCPT-I) and peroxisome proliferator-activated receptorα(PPARα). No significant differences in adipocyte size and hepatic gene expression were observed after treatment with NT-BVT compared with vehicle treated mice, though NT-BVT also decreased body weight gain, improved glucose tolerance, and increased uncoupling protein-2 (UCP-2) mRNA levels in muscle. These results suggest that an adipose tissue-targeted pharmacological inhibitor of 11β-HSD1 may prove to be a new approach for the treatment of obesity and metabolic syndrome.

Will treating diabetes with 11β-HSD1 inhibitors affect the HPA axis?

Inhibitors of 11β-HSD1 are in clinical trials for the treatment of type 2 diabetes. These compounds act by decreasing the cortisol generated in liver and adipose tissue, and therefore reducing tissue-specific gluconeogenesis and fatty acid metabolism. However, there is concern that reduction in tissue-regenerated cortisol might decrease feedback to the hypothalamic-pituitary-adrenal (HPA) axis, resulting in upregulation of cortisol from the adrenal gland. This review considers evidence from 11β-HSD1 knockout and transgenic mice, inhibitor studies and results from clinical trials evaluating HPA axis biomarkers. It is clear that analysis of the HPA axis is not sufficiently detailed, and there is a need to understand the subtle changes in the axis associated with pulsatility, diurnal rhythm and stress.

Hypothalamic-pituitary-adrenal axis abnormalities in response to deletion of 11beta-HSD1 is strain-dependent

Inter-individual differences in hypothalamic-pituitary-adrenal (HPA) axis activity underlie differential vulnerability to neuropsychiatric and metabolic disorders, although the basis of this variation is poorly understood. 11beta-Hydroxysteroid dehydrogenase type 1 (11beta-HSD1) has previously been shown to influence HPA axis activity. 129/MF1 mice null for 11beta-HSD1 (129/MF1 HSD1(-/-)) have greatly increased adrenal gland size and altered HPA activity, consistent with reduced glucocorticoid negative feedback. On this background, concentrations of plasma corticosterone and adrenocorticotrophic hormone (ACTH) were elevated in unstressed mice, and showed a delayed return to baseline after stress in HSD1-null mice with reduced sensitivity to exogenous glucocorticoid feedback compared to same-background genetic controls. In the present study, we report that the genetic background can dramatically alter this pattern. By contrast to HSD1(-/-) mice on a 129/MF1 background, HSD1(-/-) mice congenic on a C57Bl/6J background have normal basal plasma corticosterone and ACTH concentrations and exhibit normal return to baseline of plasma corticosterone and ACTH concentrations after stress. Furthermore, in contrast to 129/MF1 HSD1(-/-) mice, C57Bl/6J HSD1(-/-) mice have increased glucocorticoid receptor expression in areas of the brain involved in glucocorticoid negative feedback (hippocampus and paraventricular nucleus), suggesting this may be a compensatory response to normalise feedback control of the HPA axis. In support of this hypothesis, C57Bl/6J HSD1(-/-) mice show increased sensitivity to dexamethasone-mediated suppression of peak corticosterone. Thus, although 11beta-HSD1 appears to contribute to regulation of the HPA axis, the genetic background is crucial in governing the response to (and hence the consequences of) its loss. Similar variations in plasticity may underpin inter-individual differences in vulnerability to disorders associated with HPA axis dysregulation. They also indicate that 11beta-HSD1 inhibition does not inevitably activate the HPA axis.