Elevated hepatic 11?-hydroxysteroid dehydrogenase type 1 induces insulin resistance in uremia.
ABSTRACT: Insulin resistance and associated metabolic sequelae are common in chronic kidney disease (CKD) and are positively and independently associated with increased cardiovascular mortality. However, the pathogenesis has yet to be fully elucidated. 11?-Hydroxysteroid dehydrogenase type 1 (11?HSD1) catalyzes intracellular regeneration of active glucocorticoids, promoting insulin resistance in liver and other metabolic tissues. Using two experimental rat models of CKD (subtotal nephrectomy and adenine diet) which show early insulin resistance, we found that 11?HSD1 mRNA and protein increase in hepatic and adipose tissue, together with increased hepatic 11?HSD1 activity. This was associated with intrahepatic but not circulating glucocorticoid excess, and increased hepatic gluconeogenesis and lipogenesis. Oral administration of the 11?HSD inhibitor carbenoxolone to uremic rats for 2 wk improved glucose tolerance and insulin sensitivity, improved insulin signaling, and reduced hepatic expression of gluconeogenic and lipogenic genes. Furthermore, 11?HSD1(-/-) mice and rats treated with a specific 11?HSD1 inhibitor (UE2316) were protected from metabolic disturbances despite similar renal dysfunction following adenine experimental uremia. Therefore, we demonstrate that elevated hepatic 11?HSD1 is an important contributor to early insulin resistance and dyslipidemia in uremia. Specific 11?HSD1 inhibitors potentially represent a novel therapeutic approach for management of insulin resistance in patients with CKD.
Project description:We recently reported that inhibition of 11?-hydroxysteroid dehydrogenase 1 (11?-HSD1) by antisense oligonucleotide (ASO) improved hepatic lipid metabolism independent of food intake. In that study, 11?-HSD1 ASO-treated mice lost weight compared with food-matched control ASO-treated mice, suggesting treatment-mediated increased energy expenditure. We have now examined the effects of 11?-HSD1 ASO treatment on adipose tissue metabolism, insulin sensitivity, and whole-body energy expenditure. We used an ASO to knock down 11?-HSD1 in C57BL/6J mice consuming a Western-type diet (WTD). The 11?-HSD1 ASO-treated mice consumed less food, so food-matched control ASO-treated mice were also evaluated. We characterized body composition, gene expression of individual adipose depots, and measures of energy metabolism. We also investigated glucose/insulin tolerance as well as acute insulin signaling in several tissues. Knockdown of 11?-HSD1 protected against WTD-induced obesity by reducing epididymal, mesenteric, and subcutaneous white adipose tissue while activating thermogenesis in brown adipose tissue. The latter was confirmed by demonstrating increased energy expenditure in 11?-HSD1 ASO-treated mice. The 11?-HSD1 ASO treatment also protected against WTD-induced glucose intolerance and insulin resistance; this protection was associated with smaller cells and fewer macrophages in epididymal white adipose tissue as well as enhanced in vivo insulin signaling. Our results indicate that ASO-mediated inhibition of 11?-HSD1 can protect against several WTD-induced metabolic abnormalities. These effects are, at least in part, mediated by increases in the oxidative capacity of brown adipose tissue.
Project description:Glucocorticoids are used to treat a number of human diseases but often lead to insulin resistance and metabolic syndrome. 11?-hydroxysteroid dehydrogenase type 1 (11?-HSD1) is a key enzyme that catalyzes the intracellular conversion of cortisone to physiologically active cortisol. Despite the known role of 11?-HSD1 and active glucocorticoid in causing insulin resistance, the molecular mechanisms by which insulin resistance is induced remain elusive. The aim of this study is to identify these mechanisms in high fat diet (HFD) experimental models. Mice on a HFD were treated with 11?-HSD1 inhibitor as well as a JNK inhibitor. We then treated 3T3-L1-derived adipocytes with prednisone, a synthetic glucocorticoid, and cells with 11?-HSD1 overexpression to study insulin resistance. Our results show that 11?-HSD1 and JNK inhibition mitigated insulin resistance in HFD mice. Prednisone stimulation or overexpression of 11?-HSD1 also caused JNK activation in cultured adipocytes. Inhibition of 11?-HSD1 blocked the activation of JNK in adipose tissue of HFD mice as well as in cultured adipocytes. Furthermore, prednisone significantly impaired the insulin signaling pathway, and these effects were reversed by 11?-HSD1 and JNK inhibition. Our study demonstrates that glucocorticoid-induced insulin resistance was dependent on 11?-HSD1, resulting in the critical activation of JNK signaling in adipocytes.
Project description:Tissue-specific amplification of glucocorticoid action through 11?-hydroxysteroid dehydrogenase type 1 (11?-HSD1) affects the development of the metabolic syndrome. Hexose-6-phosphate dehydrogenase (H6PDH) mediates intracellular NADPH availability for 11?-HSD1 and depends on the glucose-6-phosphate transporter (G6PT). Little is known about the tissue-specific alterations of H6PDH and G6PT and their contributions to local glucocorticoid action in db/db mice.We characterised the role of H6PDH and G6PT in pre-receptor metabolism of glucocorticoids by examining the production of the hepatic 11?-HSD1-H6PDH-G6PT system in db/db mice.We observed that increased production of hepatic H6PDH in db/db mice was paralleled by upregulation of hepatic G6PT production and responded to elevated circulating levels of corticosterone. Treatment of db/db mice with the glucocorticoid antagonist RU486 markedly reduced production of both H6PDH and 11?-HSD1 and improved hyperglycaemia and insulin resistance. The reduction of H6PDH and 11?-HSD1 production by RU486 was accompanied by RU486-induced suppression of hepatic G6pt (also known as Slc37a4) mRNA. Incubation of mouse primary hepatocytes with corticosterone enhanced G6PT and H6PDH production with corresponding activation of 11?-HSD1 and PEPCK: effects that were blocked by RU486. Knockdown of H6pd by small interfering RNA showed effects comparable with those of RU486 for attenuating the corticosterone-induced H6PDH production and 11ß-HSD1 reductase activity in these intact cells. Addition of the G6PT inhibitor chlorogenic acid to primary hepatocytes suppressed H6PDH production.These findings suggest that increased hepatic H6PDH and G6PT production contribute to 11?-HSD1 upregulation of local glucocorticoid action that may be related to the development of type 2 diabetes.
Project description:Atherosclerotic cardiovascular disease is a major complication of chronic kidney disease (CKD). CKD leads to uremia, which modulates the phenotype of aortic smooth muscle cells (SMCs). Phenotypic modulation of SMCs plays a key role in accelerating atherosclerosis. We investigated the hypothesis that uremia potentiates neointima formation in response to vascular injury in mice. Carotid wire injury was performed on C57BL/6 wt and apolipoprotein E knockout (Apoe -/-) mice two weeks after induction of uremia by 5/6 nephrectomy. Wire injury led to neointima formation and downregulation of genes encoding classical SMC markers (i.e., myocardin, ?-smooth muscle actin, SM22-alpha, and smooth muscle myosin heavy chain) in both wt and Apoe -/- mice. Contrary to our expectations, uremia did not potentiate neointima formation, nor did it affect intimal lesion composition as judged from magnetic resonance imaging and histological analyses. Also, there was no effect of uremia on SMC marker gene expression in the injured carotid arteries, suggesting that there may be different effects of uremia on SMCs in different vascular beds. In conclusion, uremia does not accelerate neointima formation in response to wire injury of the carotid artery in mice.
Project description:BACKGROUND AND PURPOSE:11beta-Hydroxysteroid dehydrogenase type 1 (11beta-HSD1) is an attractive therapeutic target of type 2 diabetes and metabolic syndrome. Emodin, a natural product and active ingredient of various Chinese herbs, has been demonstrated to possess multiple biological activities. Here, we investigated the effects of emodin on 11beta-HSD1 and its ability to ameliorate metabolic disorders in diet-induced obese (DIO) mice. EXPERIMENTAL APPROACH:Scintillation proximity assay was performed to evaluate inhibition of emodin against recombinant human and mouse 11beta-HSDs. The ability of emodin to inhibit prednisone- or dexamethasone-induced insulin resistance was investigated in C57BL/6J mice and its effect on metabolic abnormalities was observed in DIO mice. KEY RESULTS:Emodin is a potent and selective 11beta-HSD1 inhibitor with the IC(50) of 186 and 86 nM for human and mouse 11beta-HSD1, respectively. Single oral administration of emodin inhibited 11beta-HSD1 activity of liver and fat significantly in mice. Emodin reversed prednisone-induced insulin resistance in mice, whereas it did not affect dexamethasone-induced insulin resistance, which confirmed its inhibitory effect on 11beta-HSD1 in vivo. In DIO mice, oral administration of emodin improved insulin sensitivity and lipid metabolism, and lowered blood glucose and hepatic PEPCK, and glucose-6-phosphatase mRNA. CONCLUSIONS AND IMPLICATIONS:This study demonstrated a new role for emodin as a potent and selective inhibitor of 11beta-HSD1 and its beneficial effects on metabolic disorders in DIO mice. This highlights the potential value of analogues of emodin as a new class of compounds for the treatment of metabolic syndrome or type 2 diabetes.
Project description:Glucocorticoids (GCs) are involved in multiple metabolic processes, including the regulation of insulin sensitivity and adipogenesis. Their action partly depends on their intracellular activation by 11?-hydroxysteroid dehydrogenase type 1 (11?-HSD1). We previously demonstrated that central GC administration promotes hyperphagia, body weight gain, hyperinsulinemia and marked insulin resistance at the level of skeletal muscles. Similar dysfunctions have been reported to occur upon specific overexpression of 11?-HSD1 in adipose tissue. The aim of the present study was therefore to determine whether the effects of central GC infusion may enhance local GC activation in white adipose tissue. Male Wistar and Sprague Dawley (SD) rats were intracerebroventricularly infused with GCs for 2 to 3 days. Body weight, food intake and metabolic parameters were measured, and expression of enzymes regulating 11?-HSD1, as well as that of genes regulated by GCs, were quantified. Central GC administration induced a significant increase in body weight gain and in 11?-HSD1 and resistin expression in adipose tissue. A decrease 11?-HSD1 expression was noticed in the liver of SD rats, as a partial compensatory mechanism. Such effects of GCs are centrally elicited. This model of icv dexamethasone infusion thus appears to be a valuable acute model, that helps delineating the initial metabolic defects occurring in obesity. An impaired downregulation of intracellular GC activation in adipose tissue may be important for the development of insulin resistance.
Project description:The enzyme 11?-hydroxysteroid dehydrogenase type 1 (11?-HSD1) amplifies intracellular glucocorticoid action by converting inactive glucocorticoids to their active forms in vivo. Adipose-specific overexpression of 11?-HSD1 induces metabolic syndrome in mice, whereas 11?-HSD1 null mice are resistant to it. Dietary trans and saturated fatty acids (TFAs and SFAs) are involved in the development of metabolic syndrome, whereas polyunsaturated fatty acids (PUFA) offer protection against this. Here, we report the effects of chronic feeding of different diets containing vanaspati (TFA rich), palm oil (SFA rich) and sunflower oil (PUFA rich) at 10%level on 11?-HSD1 gene expression in rat retroperitoneal adipose tissue. 11?-HSD1 gene expression was significantly higher in TFA rich diet-fed rats compared to SFA rich diet-fed rats, which in turn was significantly higher than PUFA rich diet-fed rats. Similar trend was observed in the expression of CCAAT-enhancer binding protein-? (C/EBP-?), the main transcription factor required for the expression of 11?-HSD1. We propose that TFAs and SFAs increase local amplification of glucocorticoid action in adipose tissue by upregulating 11?-HSD1 by altering C/EBP-?-gene expression. The increased levels of glucocorticoids in adipose tissue may lead to development of obesity and insulin resistance, thereby increasing the risk of developing metabolic syndrome.
Project description:Chronic, non-healing wounds impose a great burden on patients, professionals and health care systems worldwide. Diabetes mellitus (DM) and obesity are globally highly prevalent metabolic disorders and increase the risk for developing chronic wounds. Glucocorticoids (GCs) are endogenous stress hormones that exert profound effects on inflammation and repair systems. 11-beta-hydroxysteroid dehydrogenase 1 (11?-HSD1) is the key enzyme which controls local GC availability in target tissues such as skin. Since treatment with GCs has detrimental side effects on skin integrity, causing atrophy and delayed wound healing, we asked whether the dysregulated expression of 11?-HSD1 and consequently local GC levels in skin contribute to delayed wound healing in obese, diabetic db/db mice. We found increased expression of 11?-HSD1 during disturbed wound healing and in the healthy skin of obese, diabetic db/db mice. Cell analysis revealed increased expression of 11?-HSD1 in fibroblasts, myeloid cells and dermal white adipose tissue from db/db mice, while expression in keratinocytes was unaffected. Among diabetes- and obesity-related factors, insulin and insulin-like growth factor 1 down-regulated 11?-HSD1 expression in fibroblasts and myeloid cells, while glucose, fatty acids, TNF-? and IL-1? did not affect it. Insulin exerted its inhibitory effect on 11?-HSD1 expression by activating PI3-kinase/Akt-signalling. Consequently, the inhibitory effect of insulin is attenuated in fibroblasts from insulin-resistant db/db mice. We conclude that insulin resistance in obesity and diabetes prevents the down-regulation of 11?-HSD1, leading to elevated endogenous GC levels in diabetic skin, which could contribute to impaired wound healing in patients with DM.
Project description: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 11?-hydroxysteroid dehydrogenase type 1 (11?-HSD1), rather than circulating delivery, is critical to developing the phenotype of GC excess; 11?-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 11?-HSD1 KO mice developed a full Cushingoid phenotype, adipose-specific 11?-HSD1 KO mice were protected from hepatic steatosis and circulating fatty acid excess. These data challenge our current view of GC action, demonstrating 11?-HSD1, particularly in adipose tissue, is key to the development of the adverse metabolic profile associated with circulating GC excess, offering 11?-HSD1 inhibition as a previously unidentified approach to treat Cushing syndrome.
Project description:11?-hydroxysteroid dehydrogenase type 1 (11?-HSD1) catalyzes the conversion of inactive glucocorticoids to active glucocorticoids and its inhibition ameliorates obesity and metabolic syndrome. So far, no studies have reported the effect of dietary vitamin A on 11?-HSD1 activity in visceral fat and liver under normal and obese conditions. Here, we studied the effect of chronic feeding of vitamin A-enriched diet (129 mg/kg diet) on 11?-HSD1 activity in liver and visceral fat of WNIN/Ob lean and obese rats.Male, 5-month-old, lean and obese rats of WNIN/Ob strain (n = 16 for each phenotype) were divided into two subgroups consisting of 8 rats of each phenotype. Control groups received stock diet containing 2.6 mg vitamin A/kg diet, where as experimental groups received diet containing 129 mg vitamin A/Kg diet for 20 weeks. Food and water were provided ad libitum. At the end of the experiment, tissues were collected and 11?-HSD1 activity was assayed in liver and visceral fat.Vitamin A supplementation significantly decreased body weight, visceral fat mass and 11?-HSD1 activity in visceral fat of WNIN/Ob obese rats. Hepatic 11?-HSD1 activity and gene expression were significantly reduced by vitamin A supplementation in both the phenotypes. CCAAT/enhancer binding protein ? (C/EBP?), the main transcription factor essential for the expression of 11?-HSD1, decreased in liver of vitamin A fed-obese rats, but not in lean rats. Liver × receptor ? (LXR?), a nuclear transcription factor which is known to downregulate 11?-HSD1 gene expression was significantly increased by vitamin A supplementation in both the phenotypes.This study suggests that chronic consumption of vitamin A-enriched diet decreases 11?-HSD1 activity in liver and visceral fat of WNIN/Ob obese rats. Decreased 11?-HSD1 activity by vitamin A may result in decreased levels of active glucocorticoids in adipose tissue and possibly contribute to visceral fat loss in these obese rats. Studying the role of various nutrients on the regulation of 11?-HSD1 activity and expression will help in the evolving of dietary approaches to treat obesity and insulin resistance.