Acute Hypercortisolemia Exerts Depot-Specific Effects on Abdominal and Femoral Adipose Tissue Function.

Context: Glucocorticoids have pleiotropic metabolic functions, and acute glucocorticoid excess affects fatty acid metabolism, increasing systemic lipolysis. Whether glucocorticoids exert adipose tissue depot-specific effects remains unclear.

Objective: To provide an in vivo assessment of femoral and abdominal adipose tissue responses to acute glucocorticoid administration.

SFRP2 Is Associated with Increased Adiposity and VEGF Expression.

Aims: The aim of this study was to assess depot-specific expression and secretion of secreted frizzled-related protein 2 (sFRP2) by adipose tissue and its effect on adipocyte biology. We measured serum sFRP2 concentrations in 106 patients in vivo to explore its relationship to fat mass, glycaemia and insulin resistance.

Methods: Expression of sFRP2 in mouse and human tissues was assessed using polymerase chain reaction and Western blot.

5α-Reductase Type 2 Regulates Glucocorticoid Action and Metabolic Phenotype in Human Hepatocytes.

Glucocorticoids and androgens have both been implicated in the pathogenesis of nonalcoholic fatty liver disease (NAFLD); androgen deficiency in males, androgen excess in females, and glucocorticoid excess in both sexes are associated with NAFLD. Glucocorticoid and androgen action are regulated at a prereceptor level by the enzyme 5α-reductase type 2 (SRD5A2), which inactivates glucocorticoids to their dihydrometabolites and converts T to DHT. We have therefore explored the role of androgens and glucocorticoids and their metabolism by SRD5A2 upon lipid homeostasis in human hepatocytes.

11β-HSD1 is the major regulator of the tissue-specific effects of circulating glucocorticoid excess.

The adverse metabolic effects of prescribed and endogenous glucocorticoid (GC) excess, Cushing syndrome, create a significant health burden. We found that tissue regeneration of GCs by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), rather than circulating delivery, is critical to developing the phenotype of GC excess; 11β-HSD1 KO mice with circulating GC excess are protected from the glucose intolerance, hyperinsulinemia, hepatic steatosis, adiposity, hypertension, myopathy, and dermal atrophy of Cushing syndrome. Whereas liver-specific 11β-HSD1 KO mice developed a full Cushingoid phenotype, adipose-specific 11β-HSD1 KO mice were protected from hepatic steatosis and circulating fatty acid excess.

Cortisol biosynthesis in the human ocular surface innate immune response.

Innate immune responses have a critical role in regulating sight-threatening ocular surface (OcS) inflammation. While glucocorticoids (GCs) are frequently used to limit tissue damage, the role of intracrine GC (cortisol) bioavailability via 11-beta-hydroxysteroid dehydrogenase type 1 (11β-HSD1) in OcS defense, remains unresolved. We found that primary human corneal epithelial cells (PHCEC), fibroblasts (PHKF) and allogeneic macrophages (M1, GM-CSF; M2, M-CSF) were capable of generating cortisol (M1>PHKF>M2>PHCEC) but in corneal cells, this was independent of Toll-like receptor (TLR) activation.

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.

A switch in hepatic cortisol metabolism across the spectrum of non alcoholic fatty liver disease.

Context: Non alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome. NAFLD represents a spectrum of liver disease ranging from reversible hepatic steatosis, to non alcoholic steato-hepatitis (NASH) and cirrhosis. The potential role of glucocorticoids (GC) in the pathogenesis of NAFLD is highlighted in patients with GC excess, Cushing's syndrome, who develop central adiposity, insulin resistance and in 20% of cases, NAFLD.

Regulation of lipogenesis by glucocorticoids and insulin in human adipose tissue.

Patients with glucocorticoid (GC) excess, Cushing's syndrome, develop a classic phenotype characterized by central obesity and insulin resistance. GCs are known to increase the release of fatty acids from adipose, by stimulating lipolysis, however, the impact of GCs on the processes that regulate lipid accumulation has not been explored. Intracellular levels of active GC are dependent upon the activity of 11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) and we have hypothesized that 11β-HSD1 activity can regulate lipid homeostasis in human adipose tissue (Chub-S7 cell line and primary cultures of human subcutaneous (sc) and omental (om) adipocytes.

Cortisone-reductase deficiency associated with heterozygous mutations in 11beta-hydroxysteroid dehydrogenase type 1.

In peripheral target tissues, levels of active glucocorticoid hormones are controlled by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), a dimeric enzyme that catalyzes the reduction of cortisone to cortisol within the endoplasmic reticulum. Loss of this activity results in a disorder termed cortisone reductase deficiency (CRD), typified by increased cortisol clearance and androgen excess. To date, only mutations in H6PD, which encodes an enzyme supplying cofactor for the reaction, have been identified as the cause of disease.

The role of 11beta-hydroxysteroid dehydrogenase 1 in adipogenesis in thyroid-associated ophthalmopathy.

Context: Thyroid-associated ophthalmopathy (TAO) is a sight-threatening autoimmune disease in which de novo adipogenesis has been identified as a fundamental pathogenic mechanism. 11beta-Hydroxysteroid dehydrogenase 1 (11beta-HSD1) increases cortisol bioavailability and is pivotal in mediating glucocorticoid responses in adipose tissue and inflammation.

Objective: In this study we characterize 11beta-HSD1 as a determinant of the adipogenic and inflammatory pathways in TAO orbital fat (OF) compared with normal OF.

11beta-hydroxysteroid dehydrogenase type 1 regulates glucocorticoid-induced insulin resistance in skeletal muscle.

Objective: Glucocorticoid excess is characterized by increased adiposity, skeletal myopathy, and insulin resistance, but the precise molecular mechanisms are unknown. Within skeletal muscle, 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) converts cortisone (11-dehydrocorticosterone in rodents) to active cortisol (corticosterone in rodents). We aimed to determine the mechanisms underpinning glucocorticoid-induced insulin resistance in skeletal muscle and indentify how 11beta-HSD1 inhibitors improve insulin sensitivity.

Adipose cell-adrenal interactions: current knowledge and future perspectives.

The central role of adipose tissue in the development of cardiovascular and metabolic pathology has been highlighted by the discovery of mediators (adipokines) secreted by adipose tissue and their involvement in the regulation of various biological processes. In light of recent experimental data, cross-talk between adipose tissue and the adrenal gland, particularly via the mineralocorticoid aldosterone, has been proposed. Aldosterone can induce adipogenesis, and human white adipose tissue is reported to release as-yet-uncharacterized factors that stimulate adrenocortical steroidogenesis and aldosterone production.

Lack of hexose-6-phosphate dehydrogenase impairs lipid mobilization from mouse adipose tissue.

In adipose tissue, glucocorticoids regulate lipogenesis and lipolysis. Hexose-6-phosphate dehydrogenase (H6PDH) is an enzyme located in the endoplasmic reticulum that provides a cofactor for the enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1), regulating the set point of its activity and allowing for tissue-specific activation of glucocorticoids. The aim of this study was to examine the adipose tissue biology of the H6PDH null (H6PDH/KO) mouse.

Glucocorticoid modulation of insulin signaling in human subcutaneous adipose tissue.

Context: Glucocorticoid (GC) excess is characterized by central obesity, insulin resistance, and in some cases, type 2 diabetes. However, the impact of GC upon insulin signaling in human adipose tissue has not been fully explored.

Objective: We have examined the effect of GC upon insulin signaling in both human sc primary preadipocyte cultures and a novel human immortalized sc adipocyte cell line (Chub-S7) and contrasted this with observations in primary cultures of human skeletal muscle.

Characterisation of 11beta-hydroxysteroid dehydrogenase 1 in human orbital adipose tissue: a comparison with subcutaneous and omental fat.

Glucocorticoids (GCs) have a profound effect on adipose biology increasing tissue mass causing central obesity. The pre-receptor regulation of GCs by 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) that activates cortisol from cortisone has been postulated as a fundamental mechanism underlying the metabolic syndrome mediating adipocyte hyperplasia and hypertrophy in the omental (OM) depot. Orbital adipose tissue (OF) is the site of intense inflammation and tissue remodelling in several orbital inflammatory disease states.

Depot-specific prostaglandin synthesis in human adipose tissue: a novel possible mechanism of adipogenesis.

Despite the magnitude of the obesity epidemic, the mechanisms that contribute to increases in fat mass and to differences in fat depots are still poorly understood. Prostanoids have been proposed as potent adipogenic hormones, e.g.

Androgen receptor-mediated regulation of the alpha-subunit of the epithelial sodium channel in human kidney.

Rodents studies suggest that androgens are involved in sex-specific differences in blood pressure. In humans, there is no difference in blood pressure between boys and girls, but after puberty, blood pressure increases more in men than in women. We investigated androgen-dependent regulation of the alpha-subunit of the epithelial sodium channel (alphaEnaC) in human kidney and in the human renal cell line immortalized human renal proximal tubular cell line (HKC-8).

Hexose-6-phosphate dehydrogenase confers oxo-reductase activity upon 11 beta-hydroxysteroid dehydrogenase type 1.

Two isozymes of 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) interconvert active cortisol and inactive cortisone. 11 beta-HSD2 (renal) acts only as a dehydrogenase, converting cortisol to cortisone. 11 beta-HSD1 (liver) is a bi-directional enzyme in cell homogenates, whereas in intact cells it typically displays oxo-reductase activity, generating cortisol from cortisone.

Gene expression profiling of pulpal tissue reveals the molecular complexity of dental caries.

High-throughput characterisation of the molecular response of pulpal tissue under carious lesions may contribute to improved future diagnosis and treatment. To identify genes associated with this process, oligonucleotide microarrays containing approximately 15,000 human sequences were screened using pooled total RNA isolated from pulpal tissue from both healthy and carious teeth. Data analysis identified 445 genes with 2-fold or greater difference in expression level, with 85 more abundant in health and 360 more abundant in disease.

Androgen generation in adipose tissue in women with simple obesity--a site-specific role for 17beta-hydroxysteroid dehydrogenase type 5.

Women with polycystic ovary syndrome (PCOS) have high circulating androgens, thought to originate from ovaries and adrenals, and frequently suffer from the metabolic syndrome including obesity. However, serum androgens are positively associated with body mass index (BMI) not only in PCOS, but also in simple obesity, suggesting androgen synthesis within adipose tissue. Thus we investigated androgen generation in human adipose tissue, including expression of 17beta-hydroxysteroid dehydrogenase (17beta-HSD) isozymes, important regulators of sex steroid metabolism.

11beta-hydroxysteroid dehydrogenase type 1: a tissue-specific regulator of glucocorticoid response.

11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) interconverts inactive cortisone and active cortisol. Although bidirectional, in vivo it is believed to function as a reductase generating active glucocorticoid at a prereceptor level, enhancing glucocorticoid receptor activation. In this review, we discuss both the genetic and enzymatic characterization of 11beta-HSD1, as well as describing its role in physiology and pathology in a tissue-specific manner.

Mutations in the genes encoding 11beta-hydroxysteroid dehydrogenase type 1 and hexose-6-phosphate dehydrogenase interact to cause cortisone reductase deficiency.

In cortisone reductase deficiency (CRD), activation of cortisone to cortisol does not occur, resulting in adrenocorticotropin-mediated androgen excess and a phenotype resembling polycystic ovary syndrome (PCOS; refs. 1,2). This suggests a defect in the gene HSD11B1 encoding 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1), a primary regulator of tissue-specific glucocorticoid bioavailability.

11Beta-hydroxysteroid dehydrogenase type 1 in differentiating omental human preadipocytes: from de-activation to generation of cortisol.

In humans, glucocorticoids are important regulators of adipose tissue distribution and function but circulating cortisol concentrations are normal in most patients with obesity. However, intracellular glucocorticoid levels can be modified by a microsomal enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) expressed mainly in the liver and adipose tissue. Locally generated cortisol within human adipose tissue can induce preadipocyte differentiation, but the relationship between 11beta-HSD1 expression and adipogenesis is unknown.

A switch in dehydrogenase to reductase activity of 11 beta-hydroxysteroid dehydrogenase type 1 upon differentiation of human omental adipose stromal cells.

As exemplified in patients with Cushing's syndrome, glucocorticoids play an important role in regulating adipose tissue distribution and function, but circulating cortisol concentrations are normal in most patients with obesity. However, human omental adipose stromal cells (ASCs) can generate glucocorticoid locally through the expression of the enzyme 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) type 1 (11 beta-HSD1), which, in intact cells, has been considered to be an oxoreductase, converting inactive cortisone (E) to cortisol (F). Locally produced F can induce ASC differentiation, but the relationship between 11 beta-HSD1 expression and adipocyte differentiation is unknown.