Human adipose tissue under in vitro inhibition of 11beta-hydroxysteroid dehydrogenase type 1: differentiation and metabolism changes

Chronic stress and body composition disorders: implications for health and disease

Recent studies have suggested that body composition is key to health and disease. First, fat tissue is a complex, essential, and highly active metabolic and endocrine organ that responds to afferent signals from traditional hormone systems and the central nervous system but also expresses and secretes factors with important endocrine, metabolic, and immune functions. Second, skeletal muscle mass is an important predictor of health in adult life, while severe mass loss has been associated with the frailty of old age. Studies have shown that skeletal muscle is also an important endocrine organ that secretes factors with autocrine, paracrine, or endocrine actions, which have been associated with inflammatory processes. Third, the bone is also a systemic endocrine regulator playing a pivotal role in health and disease. Finally, proper hydration in humans has been neglected as a health factor, especially in adults. Chronic stress and stress hormone hypersecretion alone or associated with distinct disorders, such as anxiety, depression, obesity, metabolic syndrome, autoimmune disorders, type 2 diabetes mellitus, and polycystic ovary syndrome (PCOS), have been associated with psychological and somatic manifestations, typically, increased fat mass, osteosarcopenia/frailty, cellular dehydration, and chronic systemic inflammation. This review aims to provide new insights into the newly developed concept of stress-related osteosarcopenic obesity and its prevention.

Muscle-specific downregulation of GR levels inhibits adipogenesis in porcine intramuscular adipocyte tissue

Intramuscular adipose is conducive to good pork quality, whereas subcutaneous adipose is considered as waste in pig production. So uncovering the regulation differences between these two adiposes is helpful to tissue-specific control of fat deposition. In this study, we found the sensitivity to glucocorticoids (GCs) was lower in intramuscular adipocytes (IMA) compared with subcutaneous adipocytes (SA). Comparison of glucocorticoid receptor (GR) revealed that IMA had lower GR level which contributed to its reduced GCs sensitivity. Higher methylation levels of GR promotor 1-C and 1-H were detected in IMA compared with SA. GR expression decrease was also found in adipocytes when treated with muscle conditioned medium (MCM) in vitro, which resulted in significant inhibition of adipocytes proliferation and differentiation. Since abundant myostatin (MSTN) was detected in MCM by ELISA assay, we further investigated the effect of this myokine on adipocytes. MSTN treatment suppressed adipocytes GR expression, cell proliferation and differentiation, which mimicked the effects of MCM. The methylation levels of GR promotor 1-C and 1-H were also elevated after MSTN treatment. Our study reveals the role of GR in muscle fiber inhibition on intramuscular adipocytes, and identifies myostatin as a muscle-derived modulator for adipose GR level.

Hdac3 Deficiency Increases Marrow Adiposity and Induces Lipid Storage and Glucocorticoid Metabolism in Osteochondroprogenitor Cells

Bone loss and increased marrow adiposity are hallmarks of aging skeletons. Conditional deletion of histone deacetylase 3 (Hdac3) in murine osteochondroprogenitor cells causes osteopenia and increases marrow adiposity, even in young animals, but the origins of the increased adiposity are unclear. To explore this, bone marrow stromal cells (BMSCs) from Hdac3-depleted and control mice were cultured in osteogenic medium. Hdac3-deficient cultures accumulated lipid droplets in greater abundance than control cultures and expressed high levels of genes related to lipid storage (Fsp27/Cidec, Plin1) and glucocorticoid metabolism (Hsd11b1) despite normal levels of Pparγ2. Approximately 5% of the lipid containing cells in the wild-type cultures expressed the master osteoblast transcription factor Runx2, but this population was threefold greater in the Hdac3-depleted cultures. Adenoviral expression of Hdac3 restored normal gene expression, indicating that Hdac3 controls glucocorticoid activation and lipid storage within osteoblast lineage cells. HDAC3 expression was reduced in bone cells from postmenopausal as compared to young women, and in osteoblasts from aged as compared to younger mice. Moreover, phosphorylation of S424 in Hdac3, a posttranslational mark necessary for deacetylase activity, was suppressed in osseous cells from old mice. Thus, concurrent declines in transcription and phosphorylation combine to suppress Hdac3 activity in aging bone, and reduced Hdac3 activity in osteochondroprogenitor cells contributes to increased marrow adiposity associated with aging. © 2015 American Society for Bone and Mineral Research.

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.

11β-Hydroxysteroid dehydrogenase 1: translational and therapeutic aspects

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) interconverts the inactive glucocorticoid cortisone and its active form cortisol. It is widely expressed and, although bidirectional, in vivo it functions predominantly as an oxoreductase, generating active glucocorticoid. This allows glucocorticoid receptor activation to be regulated at a prereceptor level in a tissue-specific manner. In this review, we will discuss the enzymology and molecular biology of 11β-HSD1 and the molecular basis of cortisone reductase deficiencies. We will also address how altered 11β-HSD1 activity has been implicated in a number of disease states, and we will explore its role in the physiology and pathologies of different tissues. Finally, we will address the current status of selective 11β-HSD1 inhibitors that are in development and being tested in phase II trials for patients with the metabolic syndrome. Although the data are preliminary, therapeutic inhibition of 11β-HSD1 is also an exciting prospect for the treatment of a variety of other disorders such as osteoporosis, glaucoma, intracranial hypertension, and cognitive decline.

The Effect of High-Fat Diet-Induced Pathophysiological Changes in the Gut on Obesity: What Should be the Ideal Treatment?

Obesity is a metabolic disorder and fundamental cause of other fatal diseases including atherosclerosis and cancer. One of the main factor that contributes to the development of obesity is high-fat (HF) consumption. Lipid ingestion will initiate from the gut feedback mechanisms to regulate glucose and lipid metabolisms. But these lipid-sensing pathways are impaired in HF-induced insulin resistance, resulting in hyperglycemia. Besides that, duodenal lipid activates mucosal mast cells, leading to the disruption of the intestinal tight junction. Lipopolysaccharide that is co-transited with dietary fat postprandially, promotes the release of cytokines and the development of metabolic syndrome. HF-diet also alters microbiota composition and enhances fat storage. Although gut is protected by immune system and contains high level of antioxidants, obesity developed presumably when this protective mechanism is compromised by the presence of excessive fat. Several therapeutic approaches targeting different pathways have been proposed. There may be no one single most effective treatment, but all aimed to prevent obesity. This review will elaborate on the physiological and molecular changes in the gut that lead to obesity, and will provide a summary of potential treatments to manage these pathophysiological changes.

11-Hydroxy-β-steroid dehydrogenase gene expression in canine adipose tissue and adipocytes: stimulation by lipopolysaccharide and tumor necrosis factor α

The enzyme 11β-hydroxysteroid dehydrogenase 1 (11β-HSD-1) is expressed in a number of tissues in rodents and humans and is responsible for the reactivation of inert cortisone into cortisol. Its gene expression and activity are increased in white adipose tissue (WAT) from obese humans and may contribute to the adverse metabolic consequences of obesity and the metabolic syndrome. The extent to which 11β-HSD-1 contributes to adipose tissue function in dogs is unknown; the aim of the present study was to examine 11β-HSD-1 gene expression and its regulation by proinflammatory and anti-inflammatory agents in canine adipocytes. Real-time PCR was used to examine the expression of 11β-HSD-1 in canine adipose tissue and canine adipocytes differentiated in culture. The mRNA encoding 11β-HSD-1 was identified in all the major WAT depots in dogs and also in liver, kidney, and spleen. Quantification by real-time PCR showed that 11β-HSD-1 mRNA was least in perirenal and falciform depots and greatest in subcutaneous, omental, and gonadal depots. Greater expression was seen in the omental depot in female than in male dogs (P=0.05). Gene expression for 11β-HSD-1 was also seen in adipocytes, from both subcutaneous and visceral depots, differentiated in culture; expression was evident throughout differentiation but was generally greatest in preadipocytes and during early differentiation, declining as cells progressed to maturity. The inflammatory mediators lipopolysaccharide and tumor necrosis factor α had a main stimulatory effect on 11β-HSD-1 gene expression in canine subcutaneous adipocytes, but IL-6 had no significant effect. Treatment with dexamethasone resulted in a significant time- and dose-dependent increase in 11β-HSD-1 gene expression, with greatest effects seen at 24 h (2 nM: approximately 4-fold; 20 nM: approximately 14-fold; P=0.010 for both). When subcutaneous adipocytes were treated with the peroxisome proliferator activated receptor γ agonist rosiglitazone, similar dose- and time-dependent effects were noted. However, no effects were seen when adipocytes from the gonadal WAT depot were treated with rosiglitazone. The induction of 11β-HSD-1 expression, by the pro-inflammatory cytokine tumor necrosis factor α and by lipopolysaccharide may have implications for the pathogenesis of obesity and its associated diseases in the dog.

Targeting the pre-receptor metabolism of cortisol as a novel therapy in obesity and diabetes

Due to its impact upon health and the economy, the mechanisms that contribute to the pathogenesis of obesity and the metabolic syndrome are under intense scrutiny. In addition to understanding the pathogenesis of disease it is important to design and trial novel therapies. Patients with cortisol excess, Cushing's syndrome, have a phenotype similar to that of the metabolic syndrome and as a result there is much interest the manipulation of glucocorticoid (GC) action as a therapeutic strategy. Intracellular GC levels are regulated by 11β-hydroxysteroid dehydrogenase (11β-HSD1) which converts inactive cortisone to cortisol, thereby increasing local GC action. There is an abundance of data implicating 11β-HSD1 in the pathogenesis of obesity, type 2 diabetes and the metabolic syndrome and 11β-HSD1 is an attractive therapeutic target. Selective 11β-HSD1 inhibitors, which do not act upon 11β-HSD2 (which inactivates cortisol to cortisone) are in development. So far studies have primarily been carried out in rodents, with results showing improvements in metabolic profile. Data are now beginning to emerge from human studies and the results are promising.

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. In this study, we describe features of the GC metabolic pathways in normal human OF depot and compare it with subcutaneous (SC) and OM depots. Using an automated histological characterisation technique, OF adipocytes were found to be significantly smaller (parameters: area, maximum diameter and perimeter) than OM and SC adipocytes (P<0 x 001). Although immunohistochemical analyses demonstrated resident CD68+ cells in all three whole tissue adipose depots, OF CD68 mRNA and protein expression exceeded that of OM and SC (mRNA, P<0 x 05; protein, P<0 x 001). In addition, there was higher expression of glucocorticoid receptor (GR)alpha mRNA in the OF whole tissue depot (P<0 x 05). Conversely, 11beta-HSD1 mRNA together with the markers of late adipocyte differentiation (FABP4 and G3PDH) were significantly lower in OF. Primary cultures of OF preadipocytes demonstrated predominant 11beta-HSD1 oxo-reductase activity with minimal dehydrogenase activity. Orbital adipocytes are smaller, less differentiated, and express low levels of 11beta-HSD1 but abundant GRalpha compared with SC and OM. OF harbours a large CD68+ population. These characteristics define an orbital microenvironment that has the potential to respond to sight-threatening orbital inflammatory disease.

Ontogeny of prolyl endopeptidase and pyroglutamyl peptidase I in rat tissues. ACTA ACUST UNITED AC. 2007;139:52-58. [PMID: 17123646 DOI: org/10.1016/j.regpep.2006.10.004]

Prolyl endopeptidase and pyroglutamyl peptidase I are enzymes which participate in the degradation of thyrotropin-releasing hormone (TRH), a hormone which is thought to play an important role in the development of organs and tissues. Here, we have characterized the ontogeny of TRH degrading enzyme activity in the brain cortex, lung, heart, kidney and liver. Overall, prolyl endopeptidase activity was found to be 2 to 5 fold higher in newborn vs. adult rat tissues, with the exception of the soluble form in the liver and the particulate form in the lung. In contrast, the developmental profile of pyroglutamyl peptidase I activity was found to be more variable and tissue dependent. These results corroborate the idea that both enzymes play important, tissue-specific roles during the development and maturation of rat organs.

Ontogeny of prolyl endopeptidase and pyroglutamyl peptidase I in rat tissues

Prolyl endopeptidase and pyroglutamyl peptidase I are enzymes which participate in the degradation of thyrotropin-releasing hormone (TRH), a hormone which is thought to play an important role in the development of organs and tissues. Here, we have characterized the ontogeny of TRH degrading enzyme activity in the brain cortex, lung, heart, kidney and liver. Overall, prolyl endopeptidase activity was found to be 2 to 5 fold higher in newborn vs. adult rat tissues, with the exception of the soluble form in the liver and the particulate form in the lung. In contrast, the developmental profile of pyroglutamyl peptidase I activity was found to be more variable and tissue dependent. These results corroborate the idea that both enzymes play important, tissue-specific roles during the development and maturation of rat organs.

Intracrine modulation of gene expression by intracellular generation of active glucocorticoids

Glucocorticoids (GC) by either up-regulating or down-regulating the expression of genes influence cellular processes in every tissue and organ of the body. The enzyme 11beta-hydroxysteroid dehydrogenase Type-1 (11beta-HSD-1) confers bioactivity upon the inactive GC cortisone (E) and prednisone (P) by converting them to cortisol (F) and prednisolone (L), respectively. We sought to investigate whether gene expression modulation by GC is under the regulation of an intracrine mechanism that determines the intracellular concentration of active GC. Human cell lines were transiently and stably co-transfected with an expression construct for 11beta-HSD-1 and a GC-responsive reporter gene and incubated with active and inactive GC. Whereas in cells that were not transfected with the expression construct for 11beta-HSD-1 inactive GC had no transcriptional activity, in both transiently and stably transfected cells E and P demonstrated a dose-dependent transcriptional activity. This transcriptional potency of both inactive GC was effectively abolished by carbenoxolone, an 11beta-HSD-1 inhibitor, and was directly related to the concentration of transfected 11beta-HSD-1. We conclude that gene expression modulation by GC is under a decisive influence of target cell 11beta-HSD-1 that modulates the intracellular concentration of active GC. The intracrine mechanism is an under-appreciated aspect of GC activity that could be a potential target for future therapies aimed at modulating GC effects at the cellular level.

Evidence that the 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD1) is regulated by pentose pathway flux. Studies in rat adipocytes and microsomes

11 beta-hydroxysteroid dehydrogenase type 1 (11 beta-HSD1) catalyzes the interconversion of biologically inactive 11 keto derivatives (cortisone, 11-dehydrocorticosterone) to active glucocorticoids (cortisol, corticosterone) in fat, liver, and other tissues. It is located in the intraluminal compartment of the endoplasmic reticulum. Inasmuch as an oxo-reductase requires NADPH, we reasoned that 11 beta-HSD1 would be metabolically interconnected with the cytosolic pentose pathway because this pathway is the primary producer of reduced cellular pyridine nucleotides. To test this theory, 11 beta-HSD1 activity and pentose pathway were simultaneously measured in isolated intact rodent adipocytes. Established inhibitors of NAPDH production via the pentose pathway (dehydroandrostenedione or norepinephrine) inhibited 11 beta-HSD1 oxo-reductase while decreasing cellular NADPH content. Conversely these compounds slightly augmented the reverse, or dehydrogenase, reaction of 11 beta-HSD1. Importantly, using isolated intact microsomes, the inhibitors did not directly alter the tandem microsomal 11 beta-HSD1 and hexose-6-phosphate dehydrogenase enzyme unit. Metabolites of 11 beta-HSD1 (corticosterone or 11-dehydrocorticosterone) inhibited or increased pentose flux, respectively, demonstrating metabolic interconnectivity. Using isolated intact liver or fat microsomes, glucose-6 phosphate stimulated 11 beta-HSD1 oxo-reductase, and this effect was blocked by selective inhibitors of glucose-6-phosphate transport. In summary, we have demonstrated a metabolic interconnection between pentose pathway and 11 beta-HSD1 oxo-reductase activities that is dependent on cytosolic NADPH production. These observations link cytosolic carbohydrate flux with paracrine glucocorticoid formation. The clinical relevance of these findings may be germane to the regulation of paracrine glucocorticoid formation in disturbed nutritional states such as obesity.