scholarly journals Gene Expression from the Imprinted Dio3 Locus Is Associated with Cell Proliferation of Cultured Brown Adipocytes

Endocrinology ◽  
2007 ◽  
Vol 148 (8) ◽  
pp. 3968-3976 ◽  
Author(s):  
Arturo Hernandez ◽  
Bibian Garcia ◽  
Maria-Jesus Obregon
Keyword(s):  
Gene Expression ◽  
Thyroid Hormones ◽  
Precursor Cells ◽  
Proliferating Cells ◽  
Antisense Gene ◽  
Brown Adipocytes ◽  
Brown Adipose ◽  
Proliferation And Differentiation ◽  
And Function ◽  
Type 3

Active thyroid hormones are critical for the differentiation and function of brown adipose tissue. However, we have observed high basal and induced levels of type 3 deiodinase (D3), an enzyme that inactivates thyroid hormones and is coded by the imprinted gene Dio3, in differentiating brown preadipocytes in primary culture. We find that D3 activity and mRNA expression strongly correlate with the rate of proliferation of undifferentiated precursor cells under various conditions. Furthermore, differentiation of precursor cells to adipocytes is associated with decreased levels of D3 expression, and only very low levels of D3 mRNA are found in mature adipocytes. Dlk1, an inhibitor of adipocyte differentiation and a paternally expressed gene located in the same imprinted domain as Dio3, displayed changes in expression that parallel those of Dio3. In contrast, a 4-kb transcript for Dio3os, an antisense gene also located in the same imprinted domain, is markedly up-regulated in differentiated adipocytes. We conclude that D3 expression in differentiating preadipocytes is primarily linked to proliferating cells, whereas Dio3os expression is associated with mature adipocytes. Our results suggest that genomic imprinting and gene expression at the Dlk1/Dio3 imprinted domain may play a role in the regulation of adipocyte proliferation and differentiation.

scholarly journals Spatial Regulation of Reactive Oxygen Species via G6PD in Brown Adipocytes Supports Thermogenic Function

2021 ◽  
Author(s):  
Jee Hyung Sohn ◽  
Yul Ji ◽  
Chang-Yun Cho ◽  
Hahn Nahmgoong ◽  
Sangsoo Lim ◽  
...  
Keyword(s):  
Gene Expression ◽  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Redox Potentials ◽  
Brown Adipocytes ◽  
Erk Activation ◽  
Brown Adipose ◽  
Erk Inhibition ◽  
Glucose 6 Phosphate Dehydrogenase

Reactive oxygen species (ROS) are associated with various roles of brown adipocytes. Glucose-6-phosphate dehydrogenase (G6PD) controls cellular redox potentials by producing NADPH. Although G6PD upregulates cellular ROS levels in white adipocytes, the roles of G6PD in brown adipocytes remain elusive. Here, we found that G6PD defect in brown adipocytes impaired thermogenic function through excessive cytosolic ROS accumulation. Upon cold exposure, G6PD-deficient mutant (G6PD<sup>mut</sup>) mice exhibited cold intolerance and downregulated thermogenic gene expression in brown adipose tissue (BAT). In addition, G6PD-deficient brown adipocytes had increased cytosolic ROS levels, leading to ERK activation. In BAT of G6PD<sup>mut</sup> mice, administration of antioxidant restored the thermogenic activity by potentiating thermogenic gene expression and relieving ERK activation. Consistently, body temperature and thermogenic execution were rescued by ERK inhibition in cold-exposed G6PD<sup>mut</sup> mice. Taken together, these data suggest that G6PD in brown adipocytes would protect against cytosolic oxidative stress, leading to cold-induced thermogenesis.

RNA Synthesis by DNA Methyltransferase 1 siRNA Transfection with Cationic Liposomes into Osteoblastic Progenitor Cells Based on SiO2 Nanomagnetic Beads for Proliferation and Differentiation

2020 ◽  
Vol 20 (10) ◽  
pp. 6077-6086
Author(s):  
Qingzhen Chen ◽  
Tao Jiang ◽  
Qinshen Wang ◽  
Yongqing Huang ◽  
Min Shao
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Osteogenic Differentiation ◽  
Dna Methyltransferase ◽  
Cationic Liposomes ◽  
Precursor Cells ◽  
Dna Methyltransferase 1 ◽  
Alizarin Red ◽  
Alp Activity ◽  
Proliferation And Differentiation

DNA methylation regulated gene expression is important for osteoblast proliferation and differentiation during bone remodeling and its deregulation leads to the development of osteoporosis. DNA methyltransferase 1 (DNMT1) is an important regulator of DNA methylation. To explore the effect and mechanism of differential expression of DNMT1 in osteoblast precursor cells, DNMT1 siRNAs were designed and synthesized to interfere with DNMT1 expression in the osteoblast precursor cells, MC3T3E1 (Clone 24; MC3T3E1-24). The expression of the target gene, DNMT1, and osteogenic differentiation indicators osteoprotegerin (OPG) and receptor activator of nuclear factor-κB ligand (RANKL) were detected by real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting (WB). MTT assay was used to detect the effect on cell proliferation. Alkaline phosphatase (ALP) activity and alizarin red staining were used to detect the effect of DNMT1 on osteogenic differentiation. Hematoxylin and eosin (H&E) staining was used to detect the morphological changes in MC3T3E1-24 cells. Twenty-four hours following the transfection of MC3T3E1-24 cells with DNMT1 siRNA using cationic liposomes, DNMT1 mRNA and protein levels decreased significantly (P <0.001 for both). The reduced expression of DNMT1 promoted the OPG mRNA and protein expression (P <0.05), increased the ratio of OPG to RANKL (P <0.05), inhibited the expression of RANKL (P <0.01) without affecting the RANKL gene expression (not significant, P >0.05). The reduced expression of DNMT1 also promoted the proliferation of osteoblast precursor cells. In addition, ALP activity test and alizarin red staining showed that reduced expression of DNMT1 resulted in an increase in OPG/RANKL ratio and promoted the differentiation of the precursor cells. The cultured cells were found to have fibroblast-like appearance, and calcium nodules were observed after 7 days of conventional culture. In addition, to improve the efficiency of RNA extraction and save time, a type of silica nanomagnetic beads was used in the early stage of this study to extract RNA and assist qPCR detection of the target genes. The results showed that the magnetic beads could effectively extract RNA from the cells. In conclusion, low expression of DNMT1 affects proliferation and maturation of osteoblasts by upregulating OPG and OPG/RANKL ratio.

scholarly journals SUN-587 IDH1-Dependent Alpha-KG Regulates Brown Fat Differentiation and Function by Modulating Histone Methylation

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Won Kon Kim ◽  
Baek-Soo Han
Keyword(s):  
Histone Methylation ◽  
Molecular Mechanisms ◽  
Adipocyte Differentiation ◽  
Uncoupling Protein ◽  
Ectopic Expression ◽  
Brown Adipocyte ◽  
Brown Adipocytes ◽  
Brown Adipose ◽  
And Function ◽  
Brown Adipogenesis

Abstract Brown adipocytes play important roles in the regulation of energy homeostasis by uncoupling protein 1-mediated non-shivering thermogenesis. Recent studies suggest that brown adipocytes as novel therapeutic targets for combating obesity and associated diseases, such as type II diabetes. However, the molecular mechanisms underlying brown adipocyte differentiation and function are not fully understood. We employed previous findings obtained through proteomic studies performed to assess proteins displaying altered levels during brown adipocyte differentiation. Here, we performed assays to determine the functional significance of their altered levels during brown adipogenesis and development. We identified isocitrate dehydrogenase 1 (IDH1) as upregulated during brown adipocyte differentiation, with subsequent investigations revealing that ectopic expression of IDH1 inhibited brown adipogenesis, whereas suppression of IDH1 levels promoted differentiation of brown adipocytes. Additionally, Idh1 overexpression resulted in increased levels of intracellular α-ketoglutarate (α-KG) and inhibited the expression of genes involved in brown adipogenesis. Exogenous treatment with α-KG reduced brown adipogenesis during the early phase of differentiation, and ChIP analysis revealed that IDH1-mediated α-KG reduced trimethylation of histone H3 lysine 4 in the promoters of genes associated with brown adipogenesis. Furthermore, administration of α-KG decreased adipogenic gene expression by modulating histone methylation in brown adipose tissues of mice. These results suggested that the IDH1–α-KG axis plays an important role in regulating brown adipocyte differentiation and might represent a therapeutic target for treating metabolic diseases.

scholarly journals Peroxisome Proliferator-Activated Receptors-α and -γ, and cAMP-Mediated Pathways, Control Retinol-Binding Protein-4 Gene Expression in Brown Adipose Tissue

Endocrinology ◽  
2012 ◽  
Vol 153 (3) ◽  
pp. 1162-1173 ◽  
Author(s):  
Meritxell Rosell ◽  
Elayne Hondares ◽  
Sadahiko Iwamoto ◽  
Frank J. Gonzalez ◽  
Martin Wabitsch ◽  
...  
Keyword(s):  
Gene Expression ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Retinol Binding Protein ◽  
Peroxisome Proliferator ◽  
Brown Adipocytes ◽  
Retinol Binding Protein 4 ◽  
White Adipocytes ◽  
Brown Adipose ◽  
Rbp4 Gene

Retinol binding protein-4 (RBP4) is a serum protein involved in the transport of vitamin A. It is known to be produced by the liver and white adipose tissue. RBP4 release by white fat has been proposed to induce insulin resistance. We analyzed the regulation and production of RBP4 in brown adipose tissue. RBP4 gene expression is induced in brown fat from mice exposed to cold or treated with peroxisome proliferator-activated receptor (PPAR) agonists. In brown adipocytes in culture, norepinephrine, cAMP, and activators of PPARγ and PPARα induced RBP4 gene expression and RBP4 protein release. The induction of RBP4 gene expression by norepinephrine required intact PPAR-dependent pathways, as evidenced by impaired response of the RBP4 gene expression to norepinephrine in PPARα-null brown adipocytes or in the presence of inhibitors of PPARγ and PPARα. PPARγ and norepinephrine can also induce the RBP4 gene in white adipocytes, and overexpression of PPARα confers regulation by this PPAR subtype to white adipocytes. The RBP4 gene promoter transcription is activated by cAMP, PPARα, and PPARγ. This is mediated by a PPAR-responsive element capable of binding PPARα and PPARγ and required also for activation by cAMP. The induction of the RBP4 gene expression by norepinephrine in brown adipocytes is protein synthesis dependent and requires PPARγ-coactivator-1-α, which acts as a norepinephine-induced coactivator of PPAR on the RBP4 gene. We conclude that PPARγ- and PPARα-mediated signaling controls RBP4 gene expression and releases in brown adipose tissue, and thermogenic activation induces RBP4 gene expression in brown fat through mechanisms involving PPARγ-coactivator-1-α coactivation of PPAR signaling.

scholarly journals White, Brown, Beige/Brite: Different Adipose Cells for Different Functions?

Endocrinology ◽  
2013 ◽  
Vol 154 (9) ◽  
pp. 2992-3000 ◽  
Author(s):  
Marta Giralt ◽  
Francesc Villarroya
Keyword(s):  
Adipose Tissue ◽  
Cell Lineage ◽  
Precursor Cells ◽  
Brown Adipocyte ◽  
Brown Adipocytes ◽  
White Adipocyte ◽  
Brown Adipose ◽  
Adult Humans ◽  
Adipocyte Cell ◽  
Adipose Cells

Brown adipose tissue (BAT) is a major site of nonshivering thermogenesis in mammals. Rodent studies indicated that BAT thermogenic activity may protect against obesity. Recent findings using novel radiodiagnosis procedures revealed unanticipated high activity of BAT in adult humans. Moreover, complex processes of cell differentiation leading to the appearance of active brown adipocytes have been recently identified. The brown adipocytes clustered in defined anatomical BAT depots of rodents arise from mesenchymal precursor cells common to the myogenic cell lineage. They are being called “classical” or “developmentally programmed” brown adipocytes. However, brown adipocytes may appear after thermogenic stimuli at anatomical sites corresponding to white adipose tissue (WAT). This process is called the “browning” of WAT. The brown adipocytes appearing in WAT derive from precursor cells different from those in classical BAT and are closer to the white adipocyte cell lineage. The brown adipocytes appearing in WAT are often called “inducible, beige, or brite.” The appearance of these inducible brown adipocytes in WAT may also involve transdifferentiation processes of white-to-brown adipose cells. There is no evidence that the ultimate thermogenic function of the beige/brite adipocytes differs from that of classical brown adipocytes, although some genetic data in rodents suggest a relevant role of the browning process in protection against obesity. Although the activation of classical BAT and the browning process share common mechanisms of induction (eg, noradrenergic-mediated induction by cold), multiple novel adrenergic-independent endocrine factors that activate BAT and the browning of WAT have been identified recently. In adult humans, BAT is mainly composed of beige/brite adipocytes, although recent data indicate the persistence of classical BAT at some anatomical sites. Understanding the biological processes controlling brown adipocyte activity and differentiation could help the design of BAT-focused strategies to increase energy expenditure and fight against obesity.

scholarly journals Norepinephrine, tri-iodothyronine and insulin upregulate glyceraldehyde-3-phosphate dehydrogenase mRNA during Brown adipocyte differentiation

1999 ◽  
pp. 169-179 ◽  
Author(s):  
I Barroso ◽  
B Benito ◽  
C Garci-Jimenez ◽  
A Hernandez ◽  
MJ Obregon ◽  
...  
Keyword(s):  
De Novo ◽  
Precursor Cells ◽  
Brown Adipocyte ◽  
Mrna Levels ◽  
Brown Adipocytes ◽  
Gapdh Gene ◽  
Gapdh Mrna ◽  
Brown Adipose ◽  
Dose Dependent ◽  
De Novo Protein Synthesis

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene expression was studied in differentiating brown adipocytes. Northern blot analysis showed that GAPDH mRNA levels increased during differentiation of precursor cells into mature adipocytes, mainly in the initial stages of the differentiation process. Insulin, tri-iodothyronine (T(3)) and norepinephrine, the main regulators of brown adipose tissue function, upregulated GAPDH mRNA levels, whereas retinoic acid inhibited them. The effect of insulin was present on all culture days examined, was time- and dose-dependent, and was exerted through its own receptors, as demonstrated by comparing insulin and insulin-like growth factor (IGF)-I and -II potencies in this system. Using the transcriptional inhibitor, actinomycin D, we demonstrated that T(3), and to a lesser extent insulin, stabilized GAPDH mRNA. Experiments with cycloheximide indicated that both hormones require de novo protein synthesis to achieve their effects. Using cAMP analogs, we showed that the effect of norepinephrine is probably exerted through this second messenger. Co-operation was elucidated between norepinephrine- and insulin-mediated induction of GAPDH mRNA levels. In summary, we have demonstrated that GAPDH mRNA is subjected to multifactorial regulation in differentiating brown adipocytes that includes differentiation of precursor cells and the lipogenic/lipolytic regulators of the tissue.

scholarly journals Role of Ubiquilins for Brown Adipocyte Proteostasis and Thermogenesis

2021 ◽  
Vol 12 ◽  
Author(s):  
Carolin Muley ◽  
Stefan Kotschi ◽  
Alexander Bartelt
Keyword(s):  
Gene Expression ◽  
Quality Control ◽  
Adipose Tissue ◽  
Cold Exposure ◽  
Protein Quality ◽  
Brown Adipocyte ◽  
Brown Adipocytes ◽  
Brown Adipose ◽  
Shivering Thermogenesis

The acclimatization of brown adipose tissue (BAT) to sustained cold exposure requires an adaptive increase in proteasomal protein quality control. Ubiquilins represent a recently identified family of shuttle proteins with versatile functions in protein degradation, such as facilitating substrate targeting and proteasomal degradation. However, whether ubiquilins participate in brown adipocyte function has not been investigated so far. Here, we determine the role of ubiquilins for proteostasis and non-shivering thermogenesis in brown adipocytes. We found that Ubqln1, 2 and 4 are highly expressed in BAT and their expression was induced by cold and proteasomal inhibition. Surprisingly, silencing of ubiquilin gene expression (one or multiple in combinations) did not lead to aggravated ER stress or inflammation. Moreover, ubiquitin level and proteasomal activity under basal conditions were not impacted by loss of ubiquilins. Also, non-shivering thermogenesis measured by norepinephrine-induced respiration remained intact after loss of ubiquilins. In conclusion, ubiquilin proteins are highly abundant in BAT and regulated by cold, but they are dispensable for brown adipocyte proteostasis and thermogenesis.

Novel Aspects of White Adipose Tissue Browning by Thyroid Hormones

2019 ◽  
Vol 128 (06/07) ◽  
pp. 446-449 ◽  
Author(s):  
Kerstin Krause
Keyword(s):  
Adipose Tissue ◽  
Thyroid Hormones ◽  
White Adipose Tissue ◽  
Brown Adipocytes ◽  
Adipose Tissues ◽  
Brown Adipose ◽  
Sympathetic Nervous ◽  
Tissue Browning ◽  
Thermogenic Capacity ◽  
Thermogenic Response

AbstractThyroid hormones are essential for the full thermogenic capacity of brown adipose tissue. The thermogenic response of brown adipocytes to thyroid hormones is resulting from the synergistic interaction of thyroid hormones with the sympathetic nervous system. In recent years, evidence has been provided that thyroid hormones also induce the browning of white adipose tissues. This review will provide a brief overview about the recent findings regarding the effects of thyroid hormones on adipose tissue thermogenesis including central and peripheral regulation of white adipose tissue browning.

scholarly journals Rheb promotes brown fat thermogenesis by Notch-dependent activation of the PKA signaling pathway

2019 ◽  
Vol 11 (9) ◽  
pp. 781-790 ◽  
Author(s):  
Wen Meng ◽  
Xiuci Liang ◽  
Ting Xiao ◽  
Jing Wang ◽  
Jie Wen ◽  
...  
Keyword(s):  
Gene Expression ◽  
High Fat Diet ◽  
Energy Homeostasis ◽  
Molecular Mechanisms ◽  
Uncoupling Protein ◽  
Regulatory Subunit ◽  
Uncoupling Protein 1 ◽  
Brown Adipocytes ◽  
Brown Adipose ◽  
Beige Fat

Abstract Increasing brown and beige fat thermogenesis have an anti-obesity effect and thus great metabolic benefits. However, the molecular mechanisms regulating brown and beige fat thermogenesis remain to be further elucidated. We recently found that fat-specific knockout of Rheb promoted beige fat thermogenesis. In the current study, we show that Rheb has distinct effects on thermogenic gene expression in brown and beige fat. Fat-specific knockout of Rheb decreased protein kinase A (PKA) activity and thermogenic gene expression in brown adipose tissue of high-fat diet-fed mice. On the other hand, overexpression of Rheb activated PKA and increased uncoupling protein 1 expression in brown adipocytes. Mechanistically, Rheb overexpression in brown adipocytes increased Notch expression, leading to disassociation of the regulatory subunit from the catalytic subunit of PKA and subsequent PKA activation. Our study demonstrates that Rheb, by selectively modulating thermogenic gene expression in brown and beige adipose tissues, plays an important role in regulating energy homeostasis.

scholarly journals Critical Role of Types 2 and 3 Deiodinases in the Negative Regulation of Gene Expression by T3 in the Mouse Cerebral Cortex

Endocrinology ◽  
2012 ◽  
Vol 153 (6) ◽  
pp. 2919-2928 ◽  
Author(s):  
Arturo Hernandez ◽  
Beatriz Morte ◽  
Mónica M. Belinchón ◽  
Ainhoa Ceballos ◽  
Juan Bernal
Keyword(s):  
Gene Expression ◽  
Cerebral Cortex ◽  
Thyroid Hormone ◽  
Critical Role ◽  
Regulation Of Gene Expression ◽  
Control Of Gene Expression ◽  
High Doses ◽  
And Function ◽  
Type 3

Thyroid hormones regulate brain development and function through the control of gene expression, mediated by binding of T3 to nuclear receptors. Brain T3 concentration is tightly controlled by homeostatic mechanisms regulating transport and metabolism of T4 and T3. We have examined the role of the inactivating enzyme type 3 deiodinase (D3) in the regulation of 43 thyroid hormone-dependent genes in the cerebral cortex of 30-d-old mice. D3 inactivation increased slightly the expression of two of 22 positively regulated genes and significantly decreased the expression of seven of 21 negatively regulated genes. Administration of high doses of T3 led to significant changes in the expression of 12 positive genes and three negative genes in wild-type mice. The response to T3 treatment was enhanced in D3-deficient mice, both in the number of genes and in the amplitude of the response, demonstrating the role of D3 in modulating T3 action. Comparison of the effects on gene expression observed in D3 deficiency with those in hypothyroidism, hyperthyroidism, and type 2 deiodinase (D2) deficiency revealed that the negative genes are more sensitive to D2 and D3 deficiencies than the positive genes. This observation indicates that, in normal physiological conditions, D2 and D3 play critical roles in maintaining local T3 concentrations within a very narrow range. It also suggests that negatively and positively regulated genes do not have the same physiological significance or that their regulation by thyroid hormone obeys different paradigms at the molecular or cellular levels.

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