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1.
J Nutr Biochem ; 100: 108898, 2022 02.
Article in English | MEDLINE | ID: mdl-34748921

ABSTRACT

The adipocytes play an important role in driving the obese-state-white adipose tissue (WAT) stores the excess energy as fat, wherein brown adipose tissue (BAT) is responsible for energy expenditure via the thermoregulatory function of uncoupling protein 1 (UCP1)-the imbalance between these two onsets obesity. Moreover, the anti-obesity effects of brown-like-adipocytes (beige) in WAT are well documented. Browning, the process of transformation of energy-storing into energy-dissipating adipocytes, is a potential preventive strategy against obesity and its related diseases. In the present study, to explore an alternative source of natural products in the regulation of adipocyte transformation, we assessed the potential of theobromine (TB), a bitter alkaloid of the cacao plant, inducing browning in mice (in vivo) and primary adipocytes (in vitro). Dietary supplementation of TB significantly increased skin temperature of the inguinal region in mice and induced the expression of UCP1 protein. It also increased the expression levels of mitochondrial marker proteins in subcutaneous adipose tissues but not in visceral adipose tissues. The microarray analysis showed that TB supplementation upregulated multiple thermogenic and beige adipocyte marker genes in subcutaneous adipose tissue. Furthermore, in mouse-derived primary adipocytes, TB upregulated the expression of the UCP1 protein and mitochondrial mass in a PPARγ ligand-dependent manner. It also increased the phosphorylation levels of PPARγ coactivator 1α without affecting its protein expression. These results indicate that dietary supplementation of TB induces browning in subcutaneous WAT and enhances PPARγ-induced UCP1 expression in vitro, suggesting its potential to treat obesity.


Subject(s)
Adipocytes, Beige/physiology , Adipocytes, White/physiology , Dietary Supplements , PPAR gamma/metabolism , Theobromine/administration & dosage , Adipocytes, White/drug effects , Adipose Tissue, White/cytology , Adipose Tissue, White/metabolism , Animals , Male , Mice , Mice, Inbred C57BL , Mitochondria/metabolism , Mitophagy , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha/metabolism , Phosphorylation , Protons , Signal Transduction , Skin Temperature , Theobromine/pharmacology , Thermogenesis , Transcriptome , Uncoupling Protein 1/metabolism , Weight Gain
2.
Commun Biol ; 4(1): 1108, 2021 09 21.
Article in English | MEDLINE | ID: mdl-34548622

ABSTRACT

The activation of thermogenesis in adipose tissue has emerged as an important target for the development of novel anti-obesity therapies. Using multi-well isothermal microcalorimetry, we have demonstrated that mature murine brown and brite adipocytes produce quantifiable heat upon ß3-AR stimulation, independently of any anaerobic mechanisms. Additionally, in brite adipocytes lacking UCP1 protein, ß3-AR stimulation still induces heat production, albeit to a much lower extent than in their wildtype counterparts, suggesting that UCP1 is an essential component of adrenergic induced thermogenesis in murine brite adipocytes exvivo. Similarly, we could observe an increase in heat production in human-derived adipocytes (hMADS) upon ß-AR stimulation. Collectively, these results establish the use of isothermal microcalorimetry as a sensitive and accurate technique for measuring thermogenic responses in intact mature brite adipocytes from murine and human origin.


Subject(s)
Adipocytes, Beige/physiology , Thermogenesis/genetics , Uncoupling Protein 1/genetics , Animals , Calorimetry , Male , Mice , Uncoupling Protein 1/metabolism
3.
PLoS Biol ; 19(8): e3001348, 2021 08.
Article in English | MEDLINE | ID: mdl-34351905

ABSTRACT

Beige fat dissipates energy and functions as a defense against cold and obesity, but the mechanism for its development is unclear. We found that interleukin (IL)-25 signaling through its cognate receptor, IL-17 receptor B (IL-17RB), increased in adipose tissue after cold exposure and ß3-adrenoceptor agonist stimulation. IL-25 induced beige fat formation in white adipose tissue (WAT) by releasing IL-4 and IL-13 and promoting alternative activation of macrophages that regulate innervation and up-regulate tyrosine hydroxylase (TH) up-regulation to produce more catecholamine including norepinephrine (NE). Blockade of IL-4Rα or depletion of macrophages with clodronate-loaded liposomes in vivo significantly impaired the beige fat formation in WAT. Mice fed with a high-fat diet (HFD) were protected from obesity and related metabolic disorders when given IL-25 through a process that involved the uncoupling protein 1 (UCP1)-mediated thermogenesis. In conclusion, the activation of IL-25 signaling in WAT may have therapeutic potential for controlling obesity and its associated metabolic disorders.


Subject(s)
Adipocytes, Beige/physiology , Adipose Tissue, Beige/growth & development , Insulin Resistance , Interleukins/metabolism , Macrophages/physiology , Adrenergic beta-3 Receptor Agonists , Animals , Cold Temperature , Homeostasis , Interleukin-4/metabolism , Male , Mice, Inbred C57BL , Obesity/metabolism , Uncoupling Protein 1/physiology
4.
Front Endocrinol (Lausanne) ; 12: 696505, 2021.
Article in English | MEDLINE | ID: mdl-34367068

ABSTRACT

Brown and beige adipose tissues possess the remarkable capacity to convert energy into heat, which potentially opens novel therapeutic perspectives targeting the epidemic of metabolic syndromes such as obesity and type 2 diabetes. These thermogenic fats implement mitochondrial oxidative phosphorylation and uncouple respiration to catabolize fatty acids and glucose, which leads to an increase in energy expenditure. In particular, beige adipocytes that arise in white adipose tissue display their thermogenic capacity through various noncanonical mechanisms. This review aims to summarize the general overview of thermogenic fat, especially including the UCP1-independent adaptive thermogenesis and the emerging mechanisms of "beiging", which may provide more evidence of targeting thermogenic fat to counteract obesity and other metabolic disorders in humans.


Subject(s)
Adipose Tissue, Beige/metabolism , Lipid Metabolism/physiology , Thermogenesis/physiology , Adipocytes, Beige/cytology , Adipocytes, Beige/physiology , Adipose Tissue/metabolism , Adipose Tissue, Brown/metabolism , Adipose Tissue, White/cytology , Adipose Tissue, White/physiology , Energy Metabolism/physiology , Humans , Lipolysis/physiology
5.
Sci Immunol ; 6(61)2021 07 30.
Article in English | MEDLINE | ID: mdl-34330814

ABSTRACT

IL-33-associated type 2 innate immunity has been shown to support beige fat formation and thermogenesis in subcutaneous inguinal white adipose tissue (iWAT), but little is known about how it is regulated in iWAT. Chemerin, as a newly identified adipokine, is clinically associated with obesity and metabolic disorders. We here show that cold exposure specifically reduces chemerin and its receptor chemerin chemokine-like receptor 1 (CMKLR1) expression in iWAT. Lack of chemerin or adipocytic CMKLR1 enhances cold-induced thermogenic beige fat via potentiating type 2 innate immune responses. Mechanistically, we identify adipocytes, particularly beige adipocytes, as the main source for cold-induced IL-33, which is restricted by the chemerin-CMKLR1 axis via dampening cAMP-PKA signaling, thereby interrupting a feed-forward circuit between beige adipocytes and type 2 innate immunity that is required for cold-induced beige fat and thermogenesis. Moreover, specific deletion of adipocytic IL-33 inhibits cold-induced beige fat and type 2 innate immune responses. Last, genetic blockade of adipocytic CMKLR1 protects against diet-induced obesity and enhances the metabolic benefits of cold stimulation in preestablished obese mice. Thus, our study identifies the chemerin-CMKLR1 axis as a physiological negative regulator of thermogenic beige fat via interrupting adipose-immune communication and suggests targeting adipose CMKLR1 as a potential therapeutic strategy for obesity-related metabolic disorders.


Subject(s)
Adipocytes, Beige/physiology , Chemokines/physiology , Intercellular Signaling Peptides and Proteins/physiology , Interleukin-33/physiology , Receptors, Chemokine/physiology , Thermogenesis , Adipocytes/physiology , Adipocytes, Beige/immunology , Animals , Chemokines/genetics , Chemokines/immunology , Cold Temperature , Diet, High-Fat , Humans , Immunity, Innate , Intercellular Signaling Peptides and Proteins/genetics , Intercellular Signaling Peptides and Proteins/immunology , Interleukin-33/immunology , Male , Mice, Transgenic , Obesity/immunology , Obesity/physiopathology , Receptors, Chemokine/genetics , Receptors, Chemokine/immunology
6.
Int J Obes (Lond) ; 45(11): 2471-2481, 2021 11.
Article in English | MEDLINE | ID: mdl-34331001

ABSTRACT

BACKGROUND: Dietary bioactive compounds have been demonstrated to produce several health benefits. Genistein, an isoflavone of soy protein, and resveratrol, a polyphenol from grapes, have been shown to improve insulin sensitivity and to stimulate white adipose tissue (WAT) browning, leading to increased energy expenditure. However, it has not been demonstrated in humans whether genistein or resveratrol have the capacity to stimulate the differentiation of stromal vascular fraction (SVF) cells from white fat into beige adipocytes. SUBJECTS/METHODS: With this aim, we assessed whether stromal vascular fraction cells obtained from biopsies of the subdermal fat depots of subjects with normal body weight (NW) or from subjects with overweight/obesity with (OIR) or without (OIS) insulin resistance were able to differentiate into the beige adipose tissue lineage in vitro, by exposing the cells to genistein, resveratrol, or the combination of both. RESULTS: The results showed that SVF cells obtained from NW or OIS subjects were able to differentiate into beige adipocytes according to an increased expression of beige biomarkers including UCP1, PDRM-16, PGC1α, CIDEA, and SHOX2 upon exposure to genistein. However, SVF cells from OIR subjects were unable to differentiate into beige adipocytes with any of the inducers. Exposure to resveratrol or the combination of resveratrol/genistein did not significantly stimulate the expression of browning markers in any of the groups studied. We found that the non-responsiveness of the SVF from subjects with obesity and insulin resistance to any of the inducers was associated with an increase in the expression of endoplasmic reticulum stress markers. CONCLUSION: Consumption of genistein may stimulate WAT browning mainly in NW or OIS subjects. Thus, obesity associated with insulin resistance may be considered as a condition that prevents some beneficial effects of some dietary bioactive compounds.


Subject(s)
Adipocytes, Beige/physiology , Cell Differentiation/drug effects , Genistein/pharmacology , Insulin Resistance/physiology , Stromal Vascular Fraction/physiology , Adult , Cell Differentiation/physiology , Female , Humans , Male , Psychometrics/instrumentation , Psychometrics/methods , Stromal Vascular Fraction/metabolism , Surveys and Questionnaires
7.
Plast Reconstr Surg ; 148(3): 549-558, 2021 09 01.
Article in English | MEDLINE | ID: mdl-34292915

ABSTRACT

BACKGROUND: Fat grafting is commonly used in treating soft-tissue defects. However, the basic biology behind fat grafting is still not fully understood. Evidence of adipose browning into beige adipose tissue after fat grafting was revealed, but its role in fat grafting remains unclear. METHODS: Induced beige adipocytes and adipose-derived stem cells were obtained from human lipoaspirates and labeled with green fluorescent protein. Nude mice were each injected with 300 mg of human lipoaspirate containing green fluorescent protein-labeled adipose-derived stem cells, green fluorescent protein-labeled induced beige adipocytes, or phosphate-buffered saline. Grafted fat was harvested after 1, 4, 8, and 12 weeks for immunohistochemistry and histologic examination. Graft retention, vascularization, and adipogenic gene expression were compared. RESULTS: After 7 days' induction, adipocytes achieved browning with multilocular lipid droplets, increased mitochondria, and up-regulated browning gene expression. Fat graft retention rates at week 12 were significantly higher after injection of induced beige adipocytes than after injection of phosphate-buffered saline (46.0 ± 4.9 percent versus 31.0 ± 3.6 percent; p = 0.01), but were similar after injection of induced beige adipocytes and adipose-derived stem cells (p > 0.05). Induced beige adipocytes underwent rewhitening into white adipocytes and showed up-regulation of peroxisome proliferator-activated receptor-γ expression. Induced beige adipocytes enhanced angiogenesis, but were not active in forming vessel structures. CONCLUSIONS: Induced beige adipocytes and adipose-derived stem cells were comparable in improving fat graft retention rates. Induced beige adipocytes promote angiogenesis in a paracrine manner and are prone to rewhitening after fat grafting.


Subject(s)
Adipocytes, Beige/transplantation , Graft Survival/physiology , Subcutaneous Fat, Abdominal/transplantation , Adipocytes, Beige/physiology , Adipogenesis/physiology , Animals , Cell Differentiation , Female , Humans , Mice , Models, Animal , Neovascularization, Physiologic , Stem Cells/physiology , Subcutaneous Fat, Abdominal/cytology
8.
FASEB J ; 35(6): e21548, 2021 06.
Article in English | MEDLINE | ID: mdl-33956354

ABSTRACT

To determine whether ellagic acid (EA) induces the "beige remodeling" of white adipose tissue (WAT), we treated cold-exposed mice and mouse stromal vascular fraction (SVF) cells with EA, a phytochemical abundant in fruits and vegetables, in particular berries. We then investigated the mechanism of EA in beige remodeling with a particular focus on DRP1-mediated mitochondrial fission and SIRT3. EA induced the trans-differentiation of white adipocytes to beige adipocytes by promoting the expression of UCP1 and other brown and beige adipocytes/fat factors (PRDM16, UCP1, PGC1α, CD137, and TBX1) and mitochondrial dynamics-related factors (SIRT3, NRF1, CPT1ß, DRP1, and FIS1) in 3T3-L1/SVF cells, and these were confirmed in the inguinal WAT of a cold-exposed mouse model. The browning effect of EA was abolished by a potent DRP1 inhibitor Mdivi-1 or SIRT3 knockdown, suggesting that EA induces beige remodeling of WAT by regulating the mitochondrial dynamics and SIRT3.


Subject(s)
Adipocytes, Beige/physiology , Adipose Tissue, White/physiology , Ellagic Acid/pharmacology , Gene Expression Regulation/drug effects , Mitochondrial Dynamics , Sirtuin 3/metabolism , Adipocytes, Beige/cytology , Adipocytes, Beige/drug effects , Adipose Tissue, White/cytology , Adipose Tissue, White/drug effects , Animals , Male , Mice , Mice, Inbred C57BL , Sirtuin 3/genetics , Thermogenesis
9.
Nat Metab ; 3(4): 485-495, 2021 04.
Article in English | MEDLINE | ID: mdl-33846638

ABSTRACT

Brown adipose tissue (BAT) and beige fat function in energy expenditure in part due to their role in thermoregulation, making these tissues attractive targets for treating obesity and metabolic disorders. While prolonged cold exposure promotes de novo recruitment of brown adipocytes, the exact sources of cold-induced thermogenic adipocytes are not completely understood. Here, we identify transient receptor potential cation channel subfamily V member 1 (Trpv1)+ vascular smooth muscle (VSM) cells as previously unidentified thermogenic adipocyte progenitors. Single-cell RNA sequencing analysis of interscapular brown adipose depots reveals, in addition to the previously known platelet-derived growth factor receptor (Pdgfr)α-expressing mesenchymal progenitors, a population of VSM-derived adipocyte progenitor cells (VSM-APC) expressing the temperature-sensitive cation channel Trpv1. We demonstrate that cold exposure induces the proliferation of Trpv1+ VSM-APCs and enahnces their differentiation to highly thermogenic adipocytes. Together, these findings illustrate the landscape of the thermogenic adipose niche at single-cell resolution and identify a new cellular origin for the development of brown and beige adipocytes.


Subject(s)
Adipocytes/physiology , Cold Temperature , Hematopoietic Stem Cells/physiology , Muscle, Smooth, Vascular/physiology , TRPV Cation Channels/physiology , Thermogenesis/physiology , Adipocytes, Beige/physiology , Adipocytes, Brown/physiology , Adipose Tissue, Beige/metabolism , Adipose Tissue, Brown/physiology , Animals , Body Temperature Regulation/physiology , Cell Differentiation/genetics , Cell Differentiation/physiology , Humans , Mesenchymal Stem Cells , Mice , Mice, Inbred C57BL , Receptor, Platelet-Derived Growth Factor alpha/genetics , TRPV Cation Channels/genetics
10.
Diabetes ; 70(6): 1317-1333, 2021 06.
Article in English | MEDLINE | ID: mdl-33795413

ABSTRACT

Brown and beige adipocytes are characterized as thermogenic adipocytes and have great potential for treating obesity and associated metabolic diseases. In this article, we identify a conserved mammalian lysine 79 of histone H3 (H3K79) methyltransferase, disruptor of telomeric silencing-1 like (DOT1L), as a new epigenetic regulator that controls thermogenic adipocyte differentiation and function. We show that deletion of DOT1L in thermogenic adipocytes potently protects mice from diet-induced obesity, improves glucose homeostasis, alleviates hepatic steatosis, and facilitates adaptive thermogenesis in vivo. Loss of DOT1L in primary preadipocytes significantly promotes brown and beige adipogenesis and thermogenesis in vitro. Mechanistically, DOT1L epigenetically regulates the brown adipose tissue-selective gene program by modulating H3K79 methylation, in particular H3K79me2 modification. Thus, our study demonstrates that DOT1L exerts an important role in energy homeostasis by regulating thermogenic adipocyte differentiation and function.


Subject(s)
Adipogenesis/genetics , Histone-Lysine N-Methyltransferase/physiology , Thermogenesis/genetics , Adipocytes, Beige/physiology , Adipocytes, Brown/physiology , Animals , Cell Differentiation/genetics , Cells, Cultured , Histone-Lysine N-Methyltransferase/genetics , Histone-Lysine N-Methyltransferase/metabolism , Histones/metabolism , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Protein Processing, Post-Translational/genetics
11.
Dev Cell ; 56(7): 985-999.e4, 2021 04 05.
Article in English | MEDLINE | ID: mdl-33711247

ABSTRACT

Thermogenic beige fat found in white adipose tissue is a potential therapeutic target to curb the global obesity and diabetes epidemic. However, these inducible thermogenic beige adipocytes have been thought to be short-lived and to rapidly convert to "white-like" adipocytes after discontinuing stimuli. In this study, using effective labeling techniques and genetic mouse tools, we demonstrate that a subset of UCP1+ cells that exist within white adipose tissue are able to self-divide and contribute to new beige adipocyte recruitment in response to ß3 stimuli. When these cells are depleted or their adipogenic capability is blocked, ß3-induced beige adipocyte formation is impaired. We also identify a cell-cycle machinery of p21 and CDKN2A as a molecular basis of beige adipocyte regulation. Collectively, our findings provide new insights into the cellular and molecular mechanisms of beige adipocyte regulation and potential therapeutic opportunities to induce the beige phenotype and treat metabolic disease.


Subject(s)
Adipocytes, Beige/physiology , Adipose Tissue, White/cytology , Stem Cells/physiology , Uncoupling Protein 1/analysis , Adrenergic beta-3 Receptor Agonists/pharmacology , Animals , Cell Proliferation/drug effects , Cyclin-Dependent Kinase Inhibitor p16/genetics , Cyclin-Dependent Kinase Inhibitor p16/physiology , Cyclin-Dependent Kinase Inhibitor p21/metabolism , Gene Deletion , Genes, cdc , Male , Mice , Stem Cells/cytology , Stem Cells/drug effects , Stem Cells/metabolism
12.
Elife ; 102021 02 16.
Article in English | MEDLINE | ID: mdl-33591269

ABSTRACT

While beige adipocytes have been found to associate with dense sympathetic neurites in mouse inguinal subcutaneous white fat (iWAT), little is known about when and how this patterning is established. Here, we applied whole-tissue imaging to examine the development of sympathetic innervation in iWAT. We found that parenchymal neurites actively grow between postnatal day 6 (P6) and P28, overlapping with early postnatal beige adipogenesis. Constitutive deletion of Prdm16 in adipocytes led to a significant reduction in early postnatal beige adipocytes and sympathetic density within this window. Using an inducible, adipocyte-specific Prdm16 knockout model, we found that Prdm16 is required for guiding sympathetic growth during early development. Deleting Prdm16 in adult animals, however, did not affect sympathetic structure in iWAT. Together, these findings highlight that beige adipocyte-sympathetic neurite communication is crucial to establish sympathetic structure during the early postnatal period but may be dispensable for its maintenance in mature animals.


Mammals have two types of fatty tissue: white fat that mainly stores energy, and brown and beige fat, also known as thermogenic fat, which burns energy to generate heat. In humans, brown fat is associated with potent anti-obesity and anti-diabetes effects. A better understanding of how this type of fat develops and functions could lead to therapeutic strategies to treat these conditions. Adult human brown fat is similar to rodent inducible brown fat, also known as beige fat. In adult mice, beige fat cells need stimulation from the environment to form. Cold can lead to the generation of beige fat cells by activating a part of the nervous system known as the sympathetic nervous system. In order for this cold-induced formation of beige fat cells to take place, nerves from the sympathetic nervous system must first innervate the fatty tissue. Beige fat cells themselves are important for establishing this innervation, but it was not well understood when and how this occurs. To study the role of beige fat cells in the establishment of nerve innervation, Chi et al. used genetically modified mice whose beige fat cells are removed when they are treated with an antibiotic called doxycycline. If mice that had not been genetically modified were treated with doxycycline, they developed beige fat cells soon after birth, and these cells shortly became densely innervated by the sympathetic nervous system. However, if the mutant mice were treated with doxycycline around birth, these mice could not make beige fat cells during the treatment and failed to develop dense innervation even when they grew older. These results showed that beige fat cells that form soon after birth are necessary to establish sympathetic nervous system innervation. But are beige fat cells required to maintain this innervation as the mice grow older? To test this, Chi et al. removed them after the innervation was fully established. These mice maintained their innervation, showing that beige fat cells appear to only be required during the establishment of innervation. Understanding how the sympathetic nervous system establishes its connection to fat so cold can stimulate beige fat formation is a first step to finding new treatments for conditions such as diabetes or obesity. Exploring the timing that underlies the interactions between the sympathetic nervous system and beige fat cells may provide therapeutic targets in this direction.


Subject(s)
Adipocytes, Beige/physiology , Neurites/physiology , Subcutaneous Fat/innervation , Animals , Cell Communication , Gene Expression Regulation, Developmental , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Subcutaneous Fat/growth & development , Transcription Factors
13.
STAR Protoc ; 1(3): 100118, 2020 12 18.
Article in English | MEDLINE | ID: mdl-33377014

ABSTRACT

Studying brown and brite adipose tissue requires precise and reliable quantification of cellular thermogenesis. This protocol describes the isolation of primary murine pre-adipocytes, differentiation into thermogenic brown and brite adipocytes, and subsequent oxygen consumption analysis. Commonly applied procedures only measure basal and maximal proton leak-linked oxygen consumption but not explicitly uncoupling protein 1 (UCP1)-dependent respiration. Meaningful oxygen consumption analyses require (1) the activation of UCP1, (2) control over intracellular free-fatty-acid levels, and (3) inhibition of ATP-consuming futile cycles. For complete details on the use and execution of this protocol, please refer to Li et al. (2014, 2017, 2018) and Schweizer et al. (2018).


Subject(s)
Adipocytes, Beige/metabolism , Adipocytes, Brown/metabolism , Primary Cell Culture/methods , Adipocytes, Beige/physiology , Adipocytes, Brown/physiology , Adipose Tissue, Beige/metabolism , Adipose Tissue, Brown/metabolism , Animals , Cell Differentiation , Cells, Cultured , Mice , Mitochondria/metabolism , Mitochondrial Proteins/metabolism , Oxygen Consumption , Thermogenesis/physiology
14.
PLoS Genet ; 16(9): e1009044, 2020 09.
Article in English | MEDLINE | ID: mdl-32991581

ABSTRACT

The transcription factor nuclear factor I-A (NFIA) is a regulator of brown adipocyte differentiation. Here we show that the C-terminal 17 amino acid residues of NFIA (which we call pro#3 domain) are required for the transcriptional activity of NFIA. Full-length NFIA-but not deletion mutant lacking pro#3 domain-rescued impaired expression of PPARγ, the master transcriptional regulator of adipogenesis and impaired adipocyte differentiation in NFIA-knockout cells. Mechanistically, the ability of NFIA to penetrate chromatin and bind to the crucial Pparg enhancer is mediated through pro#3 domain. However, the deletion mutant still binds to Myod1 enhancer to repress expression of MyoD, the master transcriptional regulator of myogenesis as well as proximally transcribed non-coding RNA called DRReRNA, via competition with KLF5 in terms of enhancer binding, leading to suppression of myogenic gene program. Therefore, the negative effect of NFIA on the myogenic gene program is, at least partly, independent of the positive effect on PPARγ expression and its downstream adipogenic gene program. These results uncover multiple ways of action of NFIA to ensure optimal regulation of brown and beige adipocyte differentiation.


Subject(s)
Adipocytes, Beige/cytology , Adipocytes, Brown/cytology , Adipogenesis/physiology , Muscle Development/physiology , NFI Transcription Factors/metabolism , Adipocytes, Beige/physiology , Adipocytes, Brown/physiology , Adipogenesis/genetics , Animals , Cell Differentiation/genetics , Chromatin/genetics , Chromatin/metabolism , Gene Expression Regulation , HEK293 Cells , Humans , Mice, Inbred C57BL , Mice, Knockout , Muscle Development/genetics , MyoD Protein/genetics , Myogenin/genetics , NFI Transcription Factors/genetics , PPAR gamma/genetics , PPAR gamma/metabolism , Proline , Protein Domains
15.
Sci Rep ; 10(1): 15842, 2020 09 28.
Article in English | MEDLINE | ID: mdl-32985557

ABSTRACT

In mice, exercise, cold exposure and fasting lead to the differentiation of inducible-brown adipocytes, called beige adipocytes, within white adipose tissue and have beneficial effects on fat burning and metabolism, through heat production. This browning process is associated with an increased expression of the key thermogenic mitochondrial uncoupling protein 1, Ucp1. Egr1 transcription factor has been described as a regulator of white and beige differentiation programs, and Egr1 depletion is associated with a spontaneous increase of subcutaneous white adipose tissue browning, in absence of external stimulation. Here, we demonstrate that Egr1 mutant mice exhibit a restrained Ucp1 expression specifically increased in subcutaneous fat, resulting in a metabolic shift to a more brown-like, oxidative metabolism, which was not observed in other fat depots. In addition, Egr1 is necessary and sufficient to promote white and alter beige adipocyte differentiation of mouse stem cells. These results suggest that modulation of Egr1 expression could represent a promising therapeutic strategy to increase energy expenditure and to restrain obesity-associated metabolic disorders.


Subject(s)
Adipocytes, Beige/metabolism , Adipose Tissue, White/metabolism , Early Growth Response Protein 1/metabolism , Subcutaneous Fat/metabolism , Adipocytes, Beige/physiology , Adipose Tissue, White/physiology , Animals , Cell Differentiation , Early Growth Response Protein 1/physiology , Female , Mesenchymal Stem Cells/metabolism , Mice , Mice, Inbred C57BL , Mice, Knockout , Oxidation-Reduction , Subcutaneous Fat/physiology
16.
Biochem Biophys Res Commun ; 532(2): 205-210, 2020 11 05.
Article in English | MEDLINE | ID: mdl-32859378

ABSTRACT

Beige/brite adipocytes, which express high levels of uncoupling protein 1 (UCP1) to generate heat using stored triglycerides, are induced under specific stimuli such as cold exposure in inguinal white adipose tissue (iWAT). Although extracellular microenvironments such as extracellular matrix (ECM) stiffness are known to regulate cell behaviors, including cell differentiation into adipocytes, the effect on iWAT cells is unknown. In this study, we show that rigid ECM promotes the cell spreading of iWAT-derived preadipocytes. Furthermore, the expression of UCP1 and other thermogenic genes in iWAT cells is promoted when the cells are cultured on rigid ECM. The expression of mTOR, a kinase known to regulate the differentiation to beige adipocytes, is decreased on rigid substrates. These results suggest that ECM stiffness plays an important role in the differentiation to beige adipocytes.


Subject(s)
Adipocytes, Beige/cytology , Adipose Tissue, White/cytology , Extracellular Matrix/chemistry , Adipocytes, Beige/physiology , Adipose Tissue, White/metabolism , Animals , Cell Differentiation , Cells, Cultured , Extracellular Matrix/metabolism , Focal Adhesions , Gene Expression Regulation , Mice , Phosphorylation , TOR Serine-Threonine Kinases/metabolism , Uncoupling Protein 1/metabolism
17.
Proc Natl Acad Sci U S A ; 117(36): 22413-22422, 2020 09 08.
Article in English | MEDLINE | ID: mdl-32839323

ABSTRACT

Brown and beige adipocytes harbor the thermogenic capacity to adapt to environmental thermal or nutritional changes. Histone methylation is an essential epigenetic modification involved in the modulation of nonshivering thermogenesis in adipocytes. Here, we describe a molecular network leading by KMT5c, a H4K20 methyltransferase, that regulates adipocyte thermogenesis and systemic energy expenditure. The expression of Kmt5c is dramatically induced by a ß3-adrenergic signaling cascade in both brown and beige fat cells. Depleting Kmt5c in adipocytes in vivo leads to a decreased expression of thermogenic genes in both brown and subcutaneous (s.c.) fat tissues. These mice are prone to high-fat-diet-induced obesity and develop glucose intolerance. Enhanced transformation related protein 53 (Trp53) expression in Kmt5c knockout (KO) mice, that is due to the decreased repressive mark H4K20me3 on its proximal promoter, is responsible for the metabolic phenotypes. Together, these findings reveal the physiological role for KMT5c-mediated H4K20 methylation in the maintenance and activation of the thermogenic program in adipocytes.


Subject(s)
Adipocytes, Beige/physiology , Adipocytes, Brown/physiology , Histone-Lysine N-Methyltransferase , Thermogenesis/physiology , Tumor Suppressor Protein p53/metabolism , Adipocytes, Beige/metabolism , Adipocytes, Brown/metabolism , Animals , Diet, High-Fat , Female , Histone-Lysine N-Methyltransferase/genetics , Histone-Lysine N-Methyltransferase/metabolism , Male , Mice , Mice, Knockout , Tumor Suppressor Protein p53/genetics
18.
Food Res Int ; 136: 109303, 2020 10.
Article in English | MEDLINE | ID: mdl-32846515

ABSTRACT

As the major biologically active constituents in Ganoderma species, Ganoderma triterpenoids (GTs) also showed potential anti-obesity effect in recent reports. To further elucidate the anti-obesity effect of GTs, four new compounds Ganoderenses H-K (1-4) and four known compounds (5-8) from Ganoderma resinaceum were determined by extensive spectroscopic analysis. The absolute configurations of Ganoderenses H (1), I (2), and Resinacein S (Res S; 5) were confirmed for the first time by X-ray crystallographic analysis. Then the effects of these triterpenoids on brown/beige adipocytes were further analyzed in vitro. Our results may be summarized as follows: (1) Res S reduced lipid droplets size by regulating lipid metabolism, but not affect the differentiation of C3H10T1/2 cells. (2) Res S increased the expression of brown and beige adipocytes markers and enhanced the activity of brown and beige adipocytes (e.g., increased ß-oxidation and pro-lipolytic activities et al.) in differentiated C3H10T1/2 cells. (3) Res S induced mitochondrial biogenesis and increased mitochondrial OCR in differentiated C3H10T1/2 cells. In conclusion, Res S is potential for activating the function of brown and beige adipocytes, thus having potential therapeutic implications for obesity and associated metabolic diseases.


Subject(s)
Adipocytes, Beige/drug effects , Adipocytes, Brown/drug effects , Ganoderma/chemistry , Triterpenes/pharmacology , Adipocytes, Beige/physiology , Adipocytes, Brown/physiology , Cell Differentiation/drug effects , Cell Line , Fruiting Bodies, Fungal/chemistry , Lipid Metabolism/drug effects , Obesity/drug therapy , Obesity/prevention & control
19.
J Mol Endocrinol ; 65(3): 97-107, 2020 10.
Article in English | MEDLINE | ID: mdl-32755999

ABSTRACT

White adipose tissue (WAT) browning may have beneficial effects for treating metabolic syndrome. miRNA are important regulators of the differentiation, development, and function of brown and beige adipocytes. Here, we found that the cold-inducible miRNA17-92 cluster is enriched in brown adipose tissue (BAT) compared with WAT. Overexpression of the miR17-92 cluster in C3H10T1/2 cells, a mouse mesenchymal stem cell line, enhanced the thermogenic capacity of adipocytes. Furthermore, we observed a significant reduction in adiposity in adipose tissue-specific miR17-92 cluster transgenic (TG) mice. This finding is partly explained by dramatic increases in white fat browning and energy expenditure. Interestingly, the miR17-92 cluster stimulated WAT browning without altering BAT activity in mice. In addition, when we removed the intrascapular BAT (iBAT), the TG mice could maintain their body temperature well under cold exposure. At the molecular level, we found that the miR17-92 cluster targets Rb1, a beige cell repressor in WAT. The present study reveals a critical role for the miR17-92 cluster in regulating WAT browning. These results may be helpful for better understanding the function of beige fat, which could compensate for the lack of BAT in humans, and may open new avenues for combatting metabolic syndrome.


Subject(s)
Adipocytes, Brown/physiology , Adipocytes, White/physiology , Cell Transdifferentiation/genetics , MicroRNAs/genetics , 3T3-L1 Cells , Adipocytes, Beige/physiology , Adipose Tissue, Brown/physiology , Adipose Tissue, White/physiology , Animals , Cells, Cultured , HEK293 Cells , Humans , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , Multigene Family/physiology , Thermogenesis/genetics
20.
Metabolism ; 107: 154225, 2020 06.
Article in English | MEDLINE | ID: mdl-32275973

ABSTRACT

BACKGROUND: Caloric restriction (CR) delays the onset of metabolic and age-related disorders. Recent studies have demonstrated that formation of beige adipocytes induced by CR is strongly associated with extracellular remodeling in adipose tissue, decrease in adipose tissue inflammation, and improved systemic metabolic homeostasis. However, beige adipocytes rapidly transition to white upon CR withdrawal through unclear mechanisms. MATERIALS AND METHODS: Six-week old C57BL6 mice were fed with 40% CR chow diet for 6 weeks. Subsequently, one group of mice was switched back to ad libitum chow diet, which was continued for additional 2 weeks. Adipose tissues were assessed histologically and biochemically for beige adipocytes. RESULTS: Beige adipocytes induced by CR rapidly transition to white adipocytes when CR is withdrawn independent of parkin-mediated mitophagy. We demonstrate that the involution of mitochondria during CR withdrawal is strongly linked with a decrease in mitochondrial biogenesis. We further demonstrate that beige-to-white fat transition upon ß3-AR agonist-withdrawal could be attenuated by CR, partly via maintenance of mitochondrial biogenesis. CONCLUSION: In the model of CR, our study highlights the dominant role of mitochondrial biogenesis in the maintenance of beige adipocytes. We propose that loss of beige adipocytes upon ß3-AR agonist withdrawal could be attenuated by CR.


Subject(s)
Adipocytes, Beige/physiology , Caloric Restriction , Organelle Biogenesis , Adipocytes, White/physiology , Adipose Tissue/cytology , Adrenergic beta-3 Receptor Agonists/pharmacology , Animals , Body Composition , Cell Fusion , Diet , Insulin/blood , Mice , Mice, Inbred C57BL , Mitophagy , Oxygen Consumption , Primary Cell Culture
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