Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Liver X receptor β controls thyroid hormone feedback in the brain and regulates browning of subcutaneous white adipose tissue.

ABSTRACT: The recent discovery of browning of white adipose tissue (WAT) has raised great research interest because of its significant potential in counteracting obesity and type 2 diabetes. Browning is the result of the induction in WAT of a newly discovered type of adipocyte, the beige cell. When mice are exposed to cold or several kinds of hormones or treatments with chemicals, specific depots of WAT undergo a browning process, characterized by highly activated mitochondria and increased heat production and energy expenditure. However, the mechanisms underlying browning are still poorly understood. Liver X receptors (LXRs) are one class of nuclear receptors, which play a vital role in regulating cholesterol, triglyceride, and glucose metabolism. Following our previous finding that LXRs serve as repressors of uncoupling protein-1 (UCP1) in classic brown adipose tissue in female mice, we found that LXRs, especially LXRβ, also repress the browning process of subcutaneous adipose tissue (SAT) in male rodents fed a normal diet. Depletion of LXRs activated thyroid-stimulating hormone (TSH)-releasing hormone (TRH)-positive neurons in the paraventricular nucleus area of the hypothalamus and thus stimulated secretion of TSH from the pituitary. Consequently, production of thyroid hormones in the thyroid gland and circulating thyroid hormone level were increased. Moreover, the activity of thyroid signaling in SAT was markedly increased. Together, our findings have uncovered the basis of increased energy expenditure in male LXR knockout mice and provided support for targeting LXRs in treatment of obesity.

SUBMITTER: Miao Y

PROVIDER: S-EPMC4653192 | biostudies-other | 2015 Nov

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

Metformin prevents the pathological browning of subcutaneous white adipose tissue.

Project description:OBJECTIVE:Browning, the conversion of white adipose tissue (WAT) to a beige phenotype, has gained interest as a strategy to induce weight loss and improve insulin resistance in metabolic disorders. However, for hypermetabolic conditions stemming from burn trauma or cancer cachexia, browning is thought to contribute to energy wasting and supraphysiological nutritional requirements. Metformin's impact on this phenomenon and underlying mechanisms have not been explored. METHODS:We used both a murine burn model and human ex vivo adipose explants to assess metformin and 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR)'s effects on the development of subcutaneous beige adipose. Enzymes involved in fat homeostasis and browning, as well as mitochondrial dynamics, were assessed to determine metformin's effects. RESULTS:Treatment with the biguanide metformin lowers lipolysis in beige fat by inducing protein phosphatase 2A (PP2A) independently of adenosine monophosphate kinase (AMPK) activation. Increased PP2A activity catalyzes the dephosphorylation of acetyl-CoA carboxylase (Ser 79) and hormone sensitive lipase (Ser 660), thus promoting fat storage and the "whitening" of otherwise lipolytic beige adipocytes. Moreover, co-incubation of metformin with the PP2A inhibitor okadaic acid countered the anti-lipolytic effects of this biguanide in human adipose. Additionally, we show that metformin does not activate this pathway in the WAT of control mice and that AICAR sustains the browning of white adipose, offering further evidence that metformin acts independently of this cellular energy sensor. CONCLUSIONS:This work provides novel insights into the mechanistic underpinnings of metformin's therapeutic benefits and potential as an agent to reduce the lipotoxicity associated with hypermetabolism and adipose browning.

| S-EPMC6728757 | biostudies-literature

MKK6 controls T3-mediated browning of white adipose tissue.

Project description:Increasing the thermogenic capacity of adipose tissue to enhance organismal energy expenditure is considered a promising therapeutic strategy to combat obesity. Here, we report that expression of the p38 MAPK activator MKK6 is elevated in white adipose tissue of obese individuals. Using knockout animals and shRNA, we show that Mkk6 deletion increases energy expenditure and thermogenic capacity of white adipose tissue, protecting mice against diet-induced obesity and the development of diabetes. Deletion of Mkk6 increases T3-stimulated UC?P1 expression in adipocytes, thereby increasing their thermogenic capacity. Mechanistically, we demonstrate that, in white adipose tissue, p38 is activated by an alternative pathway involving AMPK, TAK, and TAB. Our results identify MKK6 in adipocytes as a potential therapeutic target to reduce obesity.Brown and beige adipose tissues dissipate heat via uncoupling protein 1 (UCP1). Here the authors show that the stress activated kinase MKK6 acts as a repressor of UCP1 expression, suggesting that its inhibition promotes adipose tissue browning and increases organismal energy expenditure.

| S-EPMC5636784 | biostudies-literature

Browning of Subcutaneous White Adipose Tissue in Humans after Severe Adrenergic Stress.

Project description:Since the presence of brown adipose tissue (BAT) was confirmed in adult humans, BAT has become a therapeutic target for obesity and insulin resistance. We examined whether human subcutaneous white adipose tissue (sWAT) can adopt a BAT-like phenotype using a clinical model of prolonged and severe adrenergic stress. sWAT samples were collected from severely burned and healthy individuals. A subset of burn victims were prospectively followed during their acute hospitalization. Browning of sWAT was determined by the presence of multilocular adipocytes, uncoupling protein 1 (UCP1), and increased mitochondrial density and respiratory capacity. Multilocular UCP1-positive adipocytes were found in sWAT samples from burn patients. UCP1 mRNA, mitochondrial density, and leak respiratory capacity in sWAT increased after burn trauma. Our data demonstrate that human sWAT can transform from an energy-storing to an energy-dissipating tissue, which opens new research avenues in our quest to prevent and treat obesity and its metabolic complications.

| S-EPMC4541608 | biostudies-literature

Egr1 deficiency induces browning of inguinal subcutaneous white adipose tissue in mice.

Project description:Beige adipocyte differentiation within white adipose tissue, referred to as browning, is seen as a possible mechanism for increasing energy expenditure. The molecular regulation underlying the thermogenic browning process has not been entirely elucidated. Here, we identify the zinc finger transcription factor EGR1 as a negative regulator of the beige fat program. Loss of Egr1 in mice promotes browning in the absence of external stimulation and leads to an increase of Ucp1 expression, which encodes the key thermogenic mitochondrial uncoupling protein-1. Moreover, EGR1 is recruited to the proximal region of the Ucp1 promoter in subcutaneous inguinal white adipose tissue. Transcriptomic analysis of subcutaneous inguinal white adipose tissue in the absence of Egr1 identifies the molecular signature of white adipocyte browning downstream of Egr1 deletion and highlights a concomitant increase of beige differentiation marker and a decrease in extracellular matrix gene expression. Conversely, Egr1 overexpression in mesenchymal stem cells decreases beige adipocyte differentiation, while increasing extracellular matrix production. These results reveal a role for Egr1 in blocking energy expenditure via direct Ucp1 transcription repression and highlight Egr1 as a therapeutic target for counteracting obesity.

| S-EPMC5701004 | biostudies-literature

Burn Induces Browning of the Subcutaneous White Adipose Tissue in Mice and Humans.

Project description:Burn is accompanied by long-lasting immuno-metabolic alterations referred to as hypermetabolism that are characterized by a considerable increase in resting energy expenditure and substantial whole-body catabolism. In burned patients, the length and magnitude of the hypermetabolic state is the highest of all patients and associated with profoundly increased morbidity and mortality. Unfortunately, the mechanisms involved in hypermetabolism are essentially unknown. We hypothesized that the adipose tissue plays a central role for the induction and persistence of hypermetabolism post-burn injury. Here, we show that burn induces a switch in the phenotype of the subcutaneous fat from white to beige, with associated characteristics such as increased mitochondrial mass and UCP1 expression. Our results further demonstrate the significant role of catecholamines and interleukin-6 in this process. We conclude that subcutaneous fat remodeling and browning represent an underlying mechanism that explains the elevated energy expenditure in burn-induced hypermetabolism.

| S-EPMC4662886 | biostudies-literature

Thyroid hormone receptor alpha sumoylation modulates white adipose tissue stores.

Project description:Thyroid hormone (TH) and thyroid hormone receptor (THR) regulate stem cell proliferation and differentiation during development, as well as during tissue renewal and repair in the adult. THR undergoes posttranslational modification by small ubiquitin-like modifier (SUMO). We generated the THRA (K283Q/K288R)-/- mouse model for in vivo studies and used human primary preadipocytes expressing the THRA sumoylation mutant (K283R/K288R) and isolated preadipocytes from mutant mice for in vitro studies. THRA mutant mice had reduced white adipose stores and reduced adipocyte cell diameter on a chow diet, compared to wild-type, and these differences were further enhanced after a high fat diet. Reduced preadipocyte proliferation in mutant mice, compared to wt, was shown after in vivo labeling of preadipocytes with EdU and in preadipocytes isolated from mice fat stores and studied in vitro. Mice with the desumoylated THRA had disruptions in cell cycle G1/S transition and this was associated with a reduction in the availability of cyclin D2 and cyclin-dependent kinase 2. The genes coding for cyclin D1, cyclin D2, cyclin-dependent kinase 2 and Culin3 are stimulated by cAMP Response Element Binding Protein (CREB) and contain CREB Response Elements (CREs) in their regulatory regions. We demonstrate, by Chromatin Immunoprecipitation (ChIP) assay, that in mice with the THRA K283Q/K288R mutant there was reduced CREB binding to the CRE. Mice with a THRA sumoylation mutant had reduced fat stores on chow and high fat diets and reduced adipocyte diameter.

| S-EPMC8677787 | biostudies-literature

Subcutaneous white adipose tissue independently regulates burn-induced hypermetabolism via immune-adipose crosstalk.

Project description:Severe burns induce a chronic hypermetabolic state that persists well past wound closure, indicating that additional internal mechanisms must be involved. Adipose tissue is suggested to be a central regulator in perpetuating hypermetabolism, although this has not been directly tested. Here, we show that thermogenic adipose tissues are activated in parallel to increases in hypermetabolism independent of cold stress. Using an adipose tissue transplantation model, we discover that burn-derived subcutaneous white adipose tissue alone is sufficient to invoke a hypermetabolic response in a healthy recipient mouse. Concomitantly, transplantation of healthy adipose tissue alleviates metabolic dysfunction in a burn recipient. We further show that the nicotinic acetylcholine receptor signaling pathway may mediate an immune-adipose crosstalk to regulate adipose tissue remodeling post-injury. Targeting this pathway could lead to innovative therapeutic interventions to counteract hypermetabolic pathologies.

| S-EPMC10845122 | biostudies-literature

Thyroid hormone acting via TRβ induces expression of browning genes in mouse bone marrow adipose tissue.

Project description:PurposeMutant hypothyroid mouse models have recently shown that thyroid hormone is critical for skeletal development during an important prepubertal growth period. Additionally, thyroid hormone negatively regulates total body fat, consistent with the well-established effects of thyroid hormone on energy and fat metabolism. Since bone marrow mesenchymal stromal cells differentiate into both adipocytes and osteoblasts and a relationship between bone marrow adipogenesis and osteogenesis has been predicted, we hypothesized thyroid hormone deficiency during the postnatal growth period increases marrow adiposity in mice.MethodsMarrow adiposity in TH-deficient (Tshr -/-) mice treated with T3/T4, TH receptor β-specific agonist GC-1, or vehicle control was evaluated via dual-energy X-ray absorptiometry and osmium micro-computed tomography. To further examine the mechanism for thyroid hormone regulation of marrow adiposity, we used real-time RT-PCR to measure the effects of thyroid hormone on adipocyte differentiation markers in primary mouse bone marrow mesenchymal stromal cells and two mouse cell lines in vitro and in Tshr -/- mice in vivo.ResultsMarrow adiposity increased >20% (P < 0.01) in Tshr -/- mice at 3 weeks of age, and treatment with T3/T4 when serum thyroid hormone normally increases (day 5-14) rescued this phenotype. Furthermore, GC-1 rescued this phenotype equally well, suggesting this thyroid hormone effect is in part mediated via TRβ signaling. Treatment of bone marrow mesenchymal stromal or ST2 cells with T3 or GC-1 significantly increased expression of several brown/beige fat markers. Moreover, injection of T3/T4 increased browning-specific markers in white fat of Tshr -/- mice.ConclusionsThese data suggest that thyroid hormone regulation of marrow adiposity is mediated at least in part via activation of TRβ signaling.

| S-EPMC8745377 | biostudies-literature

Egr1 deficiency induces browning of inguinal subcutaneous white adipose tissue in mice

Project description:We sequenced strand-specific rRNA-depleted librairies performed from total RNAs isolated from subcutaneous inguinal fat pads of three 2-week-old wild-type female mice and three 2-week-old Egr1-deficient female mice.

2017-11-23 | GSE91058 | GEO

MitoNEET-mediated effects on browning of white adipose tissue.

Project description:MitoNEET is an outer mitochondrial membrane protein that, upon overexpression in white adipose tissue (WAT), exerts a positive impact on tissue expansion and whole-body lipid and carbohydrate homeostasis by altering mitochondrial matrix iron metabolism. Here we determine the key transcriptional events in subcutaneous WAT of mice in response to mitoNEET overexpression and a high-fat diet (HFD). Microarray analyses at key points during weight gain upon body weight divergence with wild-type mice demonstrate that mitoNEET-enriched sWAT early on, upregulates a browning signature programme that limits WAT expansion in transgenic mice for a period of up to 12 weeks of HFD. This compensatory browning phenotype is subsequently lost, resulting in rapid WAT expansion and body weight gain. Exposure to thermoneutral temperatures during HFD prompts weight gain significantly earlier. Similar WAT expansion is achieved upon infection with an adeno-associated virus expressing mitoNEET. Collectively, the mitoNEET-enriched fat pads feature a more vascularized, anti-inflammatory and less fibrotic environment.

| S-EPMC4084619 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data