scholarly journals Mechanisms in Endocrinology: LOCAL AND SYSTEMIC EFFECTS OF GLUCOCORTICOIDS ON METABOLISM: NEW LESSONS FROM ANIMAL MODELS

2021 ◽  
Author(s):  
Michael Swarbrick ◽  
Hong Zhou ◽  
Markus Seibel
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Energy Homeostasis ◽  
Metabolic Diseases ◽  
Visceral Obesity ◽  
Metabolic Effects ◽  
Glucocorticoid Treatment ◽  
Brown Adipose ◽  
Nutrient Partitioning ◽  
Brown Adipose Tissue Thermogenesis

Glucocorticoids regulate a remarkable variety of essential functions, including development, immunomodulation, maintenance of circadian rhythm and the response to stress. Glucocorticoids acutely increase energy availability; this is accomplished not only by mobilizing energy stores, but also by diverting energy away from anabolic processes in tissues such as skeletal muscle and bone. While this metabolic shift is advantageous in the short term, prolonged glucocorticoid exposure frequently results in central obesity, insulin resistance, hyperglycaemia, dyslipidaemia, muscle wasting and osteoporosis. Understanding how glucocorticoids affect nutrient partitioning is therefore critical for preventing the side effects of glucocorticoid treatment. Independently of circulating glucocorticoids, intracellular glucocorticoid activity is regulated by the 11β-hydroxysteroid dehydrogenases 1 and 2 (11β-HSD1 and 2), which activate and inactivate glucocorticoids, respectively. Excessive 11β-HSD1 activity, amplifying local glucocorticoid activity in tissues such as adipose tissue and bone may contribute to visceral obesity, insulin resistance and aging-related bone loss in humans. Several recent findings in animals have considerably expanded our understanding of how glucocorticoids exert their dysmetabolic effects. In mice, disrupting glucocorticoid signalling in either adipose tissue or bone produces marked effects on energy homeostasis. Glucocorticoids have also been shown to influence brown adipose tissue thermogenesis (acute activation, chronic suppression), in both rodents and humans. Lastly, recent studies in mice have demonstrated that many dysmetabolic effects of glucocorticoids are sexually dimorphic, although corresponding results in humans are lacking. Together, these studies have illuminated the mechanisms by which glucocorticoids exert their metabolic effects; and have guided us towards more targeted future treatments for metabolic diseases.

scholarly journals DsbA-L deficiency in T cells promotes diet-induced thermogenesis through suppressing IFN-γ production

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Haiyan Zhou ◽  
Xinyi Peng ◽  
Jie Hu ◽  
Liwen Wang ◽  
Hairong Luo ◽  
...  
Keyword(s):  
T Cells ◽  
Adipose Tissue ◽  
T Cell ◽  
Energy Homeostasis ◽  
Metabolic Diseases ◽  
Therapeutic Potential ◽  
Whole Body ◽  
Brown Adipose ◽  
Ifn Γ ◽  
Diet Induced Thermogenesis

AbstractAdipose tissue-resident T cells have been recognized as a critical regulator of thermogenesis and energy expenditure, yet the underlying mechanisms remain unclear. Here, we show that high-fat diet (HFD) feeding greatly suppresses the expression of disulfide-bond A oxidoreductase-like protein (DsbA-L), a mitochondria-localized chaperone protein, in adipose-resident T cells, which correlates with reduced T cell mitochondrial function. T cell-specific knockout of DsbA-L enhances diet-induced thermogenesis in brown adipose tissue (BAT) and protects mice from HFD-induced obesity, hepatosteatosis, and insulin resistance. Mechanistically, DsbA-L deficiency in T cells reduces IFN-γ production and activates protein kinase A by reducing phosphodiesterase-4D expression, leading to increased BAT thermogenesis. Taken together, our study uncovers a mechanism by which T cells communicate with brown adipocytes to regulate BAT thermogenesis and whole-body energy homeostasis. Our findings highlight a therapeutic potential of targeting T cells for the treatment of over nutrition-induced obesity and its associated metabolic diseases.

scholarly journals РОЛЬ МАРКЕРА КОСТНОГО РЕМОДЕЛИРОВАНИЯ ОСТЕОКАЛЬЦИНА В РЕГУЛЯЦИИ ЭНЕРГЕТИЧЕСКОГО ГОМЕОСТАЗА ПРИ САХАРНОМ ДИАБЕТЕ 2 ТИПА

World Science ◽  
2020 ◽  
Vol 2 (5(57)) ◽  
pp. 20-29
Author(s):  
Ковальчук А. В. ◽  
Зиныч О. В. ◽  
Корпачев В. В. ◽  
Кушнарева Н. Н. ◽  
Прибила О. В.
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Adipose Tissue ◽  
Energy Homeostasis ◽  
Visceral Obesity ◽  
Mineral Density ◽  
General Group ◽  
Men And Women ◽  
Visceral Adipose

Osteocalcin (OK) is actively involved in the humoral regulation of energy homeostasis. However, the relationship between the level of OK as a modulator of metabolic processes and constitutional and metabolic features in patients with type 2 diabetes mellitus (DM) of a different gender remains not thoroughly studied.The study included 127 patients with type 2 diabetes ≥ 50 years of age. Of these, 70 were postmenopausal women and 57 men.It was found that in the general group of women, the concentration of OK in the blood serum was significantly higher than in men. The observed difference is due to significantly higher levels of OK in women of the older age group (≥ 60 years) in comparison with men. At the same time, a decrease in bone mineral density (BMD) in the femoral neck was observed in subgroups of men and women aged ≥ 60 years and older, while in the younger subgroups of patients, the BMD of lumbar and femoral zones were close to each other.The relationships between OK levels and adipose tissue parameters, evaluated by calculating the morphological and functional index of visceral obesity (IVO), were investigated. An increase in the OK level in the groups of men and women was accompanied by a decrease in the IVO values. The highest degree of insulin resistance was determined in groups of patients with minimal levels of OK and high IVO, and the lowest values were recorded in patients with high levels of OK and low IVO.The decrease of the blood OK level in patients with type 2 diabetes occurs in parallel with an increase in the degree of insulin resistance and dysfunction of visceral adipose tissue. In this case, IVO is a more accurate parameter reflecting the constitutional and metabolic phenotypic changes, compared with the index of the waist circumference. The decrease in BMD in patients with type 2 diabetes is the result of predominantly involutive processes that are noticeable at the age of ≥ 60 years and occur against the background of a decrease in the content of OK with age.

scholarly journals Effects of ERβ and ERα on OVX-induced changes in adiposity and insulin resistance

2020 ◽  
Vol 245 (1) ◽  
pp. 165-178 ◽  
Author(s):  
Terese M Zidon ◽  
Jaume Padilla ◽  
Kevin L Fritsche ◽  
Rebecca J Welly ◽  
Leighton T McCabe ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Estrogen Receptor ◽  
Adipose Tissue ◽  
Energy Expenditure ◽  
Estrogen Receptor Alpha ◽  
Metabolic Diseases ◽  
Metabolic Effects ◽  
Metabolic Dysfunction ◽  
Gene And Protein Expression ◽  
Induced Changes

Loss of ovarian hormones leads to increased adiposity and insulin resistance (IR), increasing the risk for cardiovascular and metabolic diseases. The purpose of this study was to investigate whether the molecular mechanism behind the adverse systemic and adipose tissue-specific metabolic effects of ovariectomy requires loss of signaling through estrogen receptor alpha (ERα) or estrogen receptor β (ERβ). We examined ovariectomized (OVX) and ovary-intactwild-type (WT), ERα-null (αKO), and ERβ-null (βKO) female mice (age ~49 weeks; n = 7–12/group). All mice were fed a phytoestrogen-free diet (<15 mg/kg) and either remained ovary-intact (INT) or were OVX and followed for 12 weeks. Body composition, energy expenditure, glucose tolerance, and adipose tissue gene and protein expression were analyzed. INT αKO were ~25% fatter with reduced energy expenditure compared to age-matched INT WT controls and βKO mice (all P < 0.001). Following OVX, αKO mice did not increase adiposity or experience a further increase in IR, unlike WT and βKO, suggesting that loss of signaling through ERα mediates OVX-induced metabolic dysfunction. In fact, OVX in αKO mice (i.e., signaling through ERβ in the absence of ERα) resulted in reduced adiposity, adipocyte size, and IR (P < 0.05 for all). βKO mice responded adversely to OVX in terms of increased adiposity and development of IR. Together, these findings challenge the paradigm that ERα mediates metabolic protection over ERβ in all settings. These findings lead us to suggest that, following ovarian hormone loss, ERβ may mediate protective metabolic benefits.

scholarly journals Median preoptic area neurons are required for the cooling and febrile activations of brown adipose tissue thermogenesis in rat

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ellen Paula Santos da Conceição ◽  
Shaun F. Morrison ◽  
Georgina Cano ◽  
Pierfrancesco Chiavetta ◽  
Domenico Tupone
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Cold Exposure ◽  
Energy Homeostasis ◽  
Preoptic Area ◽  
Therapeutic Approaches ◽  
Dorsomedial Hypothalamus ◽  
Brown Adipose ◽  
Brown Adipose Tissue Thermogenesis

Abstract Within the central neural circuitry for thermoregulation, the balance between excitatory and inhibitory inputs to the dorsomedial hypothalamus (DMH) determines the level of activation of brown adipose tissue (BAT) thermogenesis. We employed neuroanatomical and in vivo electrophysiological techniques to identify a source of excitation to thermogenesis-promoting neurons in the DMH that is required for cold defense and fever. Inhibition of median preoptic area (MnPO) neurons blocked the BAT thermogenic responses during both PGE2-induced fever and cold exposure. Disinhibition or direct activation of MnPO neurons induced a BAT thermogenic response in warm rats. Blockade of ionotropic glutamate receptors in the DMH, or brain transection rostral to DMH, blocked cold-evoked or NMDA in MnPO-evoked BAT thermogenesis. RNAscope technique identified a glutamatergic population of MnPO neurons that projects to the DMH and expresses c-Fos following cold exposure. These discoveries relative to the glutamatergic drive to BAT sympathoexcitatory neurons in DMH augment our understanding of the central thermoregulatory circuitry in non-torpid mammals. Our data will contribute to the development of novel therapeutic approaches to induce therapeutic hypothermia for treating drug-resistant fever, and for improving glucose and energy homeostasis.

scholarly journals The Role of Adipose Tissue Mitochondria: Regulation of Mitochondrial Function for the Treatment of Metabolic Diseases

2019 ◽  
Vol 20 (19) ◽  
pp. 4924 ◽  
Author(s):  
Lee ◽  
Park ◽  
Oh ◽  
Lee ◽  
Kim ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Mitochondrial Function ◽  
Energy Homeostasis ◽  
Metabolic Diseases ◽  
Oxidative Capacity ◽  
Adipose Tissues ◽  
Adaptive Thermogenesis ◽  
Brown Adipose

: Mitochondria play a key role in maintaining energy homeostasis in metabolic tissues, including adipose tissues. The two main types of adipose tissues are the white adipose tissue (WAT) and the brown adipose tissue (BAT). WAT primarily stores excess energy, whereas BAT is predominantly responsible for energy expenditure by non-shivering thermogenesis through the mitochondria. WAT in response to appropriate stimuli such as cold exposure and β-adrenergic agonist undergoes browning wherein it acts as BAT, which is characterized by the presence of a higher number of mitochondria. Mitochondrial dysfunction in adipocytes has been reported to have strong correlation with metabolic diseases, including obesity and type 2 diabetes. Dysfunction of mitochondria results in detrimental effects on adipocyte differentiation, lipid metabolism, insulin sensitivity, oxidative capacity, and thermogenesis, which consequently lead to metabolic diseases. Recent studies have shown that mitochondrial function can be improved by using thiazolidinedione, mitochondria-targeted antioxidants, and dietary natural compounds; by performing exercise; and by controlling caloric restriction, thereby maintaining the metabolic homeostasis by inducing adaptive thermogenesis of BAT and browning of WAT. In this review, we focus on and summarize the molecular regulation involved in the improvement of mitochondrial function in adipose tissues so that strategies can be developed to treat metabolic diseases.

scholarly journals Orally Induced Hyperthyroidism Regulates Hypothalamic AMP-Activated Protein Kinase

Nutrients ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 4204
Author(s):  
Valentina Capelli ◽  
Carmen Grijota-Martínez ◽  
Nathalia R. V. Dragano ◽  
Eval Rial-Pensado ◽  
Johan Fernø ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Protein Kinase ◽  
Energy Homeostasis ◽  
Uncoupling Protein ◽  
Core Body Temperature ◽  
Metabolic Effects ◽  
Central Administration ◽  
Treatment Protocols ◽  
Brown Adipose ◽  
Amp Activated Protein Kinase

Besides their direct effects on peripheral metabolic tissues, thyroid hormones (TH) act on the hypothalamus to modulate energy homeostasis. However, since most of the hypothalamic actions of TH have been addressed in studies with direct central administration, the estimation of the relative contribution of the central vs. peripheral effects in physiologic conditions of peripheral release (or administration) of TH remains unclear. In this study we used two different models of peripherally induced hyperthyroidism (i.e., T4 and T3 oral administration) to assess and compare the serum and hypothalamic TH status and relate them to the metabolic effects of the treatment. Peripheral TH treatment affected feeding behavior, overall growth, core body temperature, body composition, brown adipose tissue (BAT) morphology and uncoupling protein 1 (UCP1) levels and metabolic activity, white adipose tissue (WAT) browning and liver metabolism. This resulted in an increased overall uncoupling capacity and a shift of the lipid metabolism from WAT accumulation to BAT fueling. Both peripheral treatment protocols induced significant changes in TH concentrations within the hypothalamus, with T3 eliciting a downregulation of hypothalamic AMP-activated protein kinase (AMPK), supporting the existence of a central action of peripheral TH. Altogether, these data suggest that peripherally administered TH modulate energy balance by various mechanisms; they also provide a unifying vision of the centrally mediated and the direct local metabolic effect of TH in the context of hyperthyroidism.

scholarly journals TFEB drives PGC-1α expression in adipocytes to protect against diet-induced metabolic dysfunction

2019 ◽  
Vol 12 (606) ◽  
pp. eaau2281 ◽  
Author(s):  
Trent D. Evans ◽  
Xiangyu Zhang ◽  
Se-Jin Jeong ◽  
Anyuan He ◽  
Eric Song ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Metabolic Diseases ◽  
Therapeutic Potential ◽  
Metabolic Effects ◽  
Metabolic Dysfunction ◽  
Helix Loop Helix ◽  
Downstream Effects ◽  
Brown Adipose ◽  
Tissue Browning

TFEB is a basic helix-loop-helix transcription factor that confers protection against metabolic diseases such as atherosclerosis by targeting a network of genes involved in autophagy-lysosomal biogenesis and lipid catabolism. In this study, we sought to characterize the role of TFEB in adipocyte and adipose tissue physiology and evaluate the therapeutic potential of adipocyte-specific TFEB overexpression in obesity. We demonstrated that mice with adipocyte-specific TFEB overexpression (Adipo-TFEB) were protected from diet-induced obesity, insulin resistance, and metabolic sequelae. Adipo-TFEB mice were lean primarily through increased metabolic rate, suggesting a role for adipose tissue browning and enhanced nonshivering thermogenesis in fat. Transcriptional characterization revealed that TFEB targeted genes involved in adipose tissue browning rather than those involved in autophagy. One such gene encoded PGC-1α, an established target of TFEB that promotes adipocyte browning. To dissect the role of PGC-1α in mediating the downstream effects of TFEB overexpression, we generated mice with adipocyte-specific PGC-1α deficiency and TFEB overexpression. Without PGC-1α, the ability of TFEB overexpression to brown adipose tissue and to elicit beneficial metabolic effects was blunted. Overall, these data implicate TFEB as a PGC-1α–dependent regulator of adipocyte browning and suggest its therapeutic potential in treating metabolic disease.

scholarly journals Incendiary Leptin

Nutrients ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 472 ◽  
Author(s):  
Patricia Seoane-Collazo ◽  
Noelia Martínez-Sánchez ◽  
Edward Milbank ◽  
Cristina Contreras
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Metabolic Profile ◽  
Metabolic Disorders ◽  
Energy Homeostasis ◽  
Scientific Evidence ◽  
Rodent Models ◽  
Leptin Receptors ◽  
Brown Adipose ◽  
Dual Capacity

Leptin is a hormone released by adipose tissue that plays a key role in the control of energy homeostasis through its binding to leptin receptors (LepR), mainly expressed in the hypothalamus. Most scientific evidence points to leptin’s satiating effect being due to its dual capacity to promote the expression of anorexigenic neuropeptides and to reduce orexigenic expression in the hypothalamus. However, it has also been demonstrated that leptin can stimulate (i) thermogenesis in brown adipose tissue (BAT) and (ii) the browning of white adipose tissue (WAT). Since the demonstration of the importance of BAT in humans 10 years ago, its study has aroused great interest, mainly in the improvement of obesity-associated metabolic disorders through the induction of thermogenesis. Consequently, several strategies targeting BAT activation (mainly in rodent models) have demonstrated great potential to improve hyperlipidemias, hepatic steatosis, insulin resistance and weight gain, leading to an overall healthier metabolic profile. Here, we review the potential therapeutic ability of leptin to correct obesity and other metabolic disorders, not only through its satiating effect, but by also utilizing its thermogenic properties.

scholarly journals High-fructose feeding suppresses cold-stimulated brown adipose tissue glucose uptake in young men independently of changes in thermogenesis and the gut microbiome

2022 ◽  
Author(s):  
Gabriel Richard ◽  
Denis P. Blondin ◽  
Saad A. Syed ◽  
Laura Rossi ◽  
Michelle E. Fontes ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Glucose Uptake ◽  
High Glucose ◽  
Gut Microbiome ◽  
Metabolic Diseases ◽  
Short Chain Fatty Acids ◽  
Alcoholic Fatty Liver ◽  
High Fructose ◽  
Brown Adipose

Diets rich in added sugars, especially high in fructose, are associated with metabolic diseases such as insulin resistance, and non-alcoholic fatty liver disease. Studies have shown a link between these pathologies and changes in the microbiome and its metabolites. Given the reported associations in animal models between the microbiome and brown or beige adipose tissue (BAT) function, and the alterations in the microbiome induced by high glucose or high fructose diets, we investigated the potential causal link between high glucose or fructose diets and BAT dysfunction in humans. We show that BAT glucose uptake, but not thermogenesis, is impaired by a high fructose but not high glucose diet, in the absence of changes in body mass, the gastrointestinal microbiome, and faecal short-chain fatty acids. We conclude that BAT metabolic dysfunction occurs independently from changes in gut microbiome composition, and earlier than other pathophysiological abnormalities associated with insulin resistance and dyslipidemia during fructose overconsumption in humans.

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