GPAT3 deficiency alleviates insulin resistance and hepatic steatosis in a mouse model of severe congenital generalized lipodystrophy

2019 ◽  
Vol 29 (3) ◽  
pp. 432-443 ◽  
Author(s):  
Mingming Gao ◽  
Lin Liu ◽  
Xiaowei Wang ◽  
Hoi Yin Mak ◽  
George Liu ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Liver Steatosis ◽  
Subcutaneous Fat ◽  
Severe Form ◽  
Loss Of Function ◽  
Tissue Mass ◽  
Functional Link ◽  
Brown Adipose

Abstract Berardinelli-Seip congenital lipodystrophy type 2 (BSCL2) is the most severe form of human lipodystrophy and is caused by loss-of-function mutations in the BSCL2/seipin gene. Exactly how seipin may regulate adipogenesis remains unclear. A recent study in vitro suggested that seipin may function to inhibit the activity of glycerol-3-phosphate acyltransferases (GPATs), and increased GPAT activity may be responsible for the defective adipogenesis under seipin deficiency. Here we generated Seipin−/−Gpat3−/− mice, which had mild but significant recovery of white adipose tissue mass over Seipin−/− mice. The mass of brown adipose tissue (BAT) of the Seipin−/−Gpat3−/− mice was almost completely restored to normal level. Importantly, the Seipin−/−Gpat3−/− mice showed significant improvement in liver steatosis and insulin sensitivity over Seipin−/− mice, which is attributable to the increased BAT mass and to the enhanced browning of the subcutaneous fat of the Seipin−/−Gpat3−/− mice. Together, our results establish a functional link between seipin and GPAT3 in vivo and suggest that GPAT inhibitors may have beneficial effects on BSCL2 patients.

scholarly journals JAZF1 heterozygous knockout mice show altered adipose development and metabolism

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jain Jeong ◽  
Soyoung Jang ◽  
Song Park ◽  
Wookbong Kwon ◽  
Si-Yong Kim ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Knockout Mice ◽  
Metabolic Disorders ◽  
Adipocyte Differentiation ◽  
Zinc Finger Protein ◽  
Tissue Mass ◽  
In Vivo Models ◽  
Brown Adipose

Abstract Background Juxtaposed with another zinc finger protein 1 (JAZF1) is associated with metabolic disorders, including type 2 diabetes mellitus (T2DM). Several studies showed that JAZF1 and body fat mass are closely related. We attempted to elucidate the JAZF1 functions on adipose development and related metabolism using in vitro and in vivo models. Results The JAZF1 expression was precisely regulated during adipocyte differentiation of 3T3-L1 preadipocyte and mouse embryonic fibroblasts (MEFs). Homozygous JAZF1 deletion (JAZF1-KO) resulted in impaired adipocyte differentiation in MEF. The JAZF1 role in adipocyte differentiation was demonstrated by the regulation of PPARγ—a key regulator of adipocyte differentiation. Heterozygous JAZF1 deletion (JAZF1-Het) mice fed a normal diet (ND) or a high-fat diet (HFD) had less adipose tissue mass and impaired glucose homeostasis than the control (JAZF1-Cont) mice. However, other metabolic organs, such as brown adipose tissue and liver, were negligible effect on JAZF1 deficiency. Conclusion Our findings emphasized the JAZF1 role in adipocyte differentiation and related metabolism through the heterozygous knockout mice. This study provides new insights into the JAZF1 function in adipose development and metabolism, informing strategies for treating obesity and related metabolic disorders.

scholarly journals TAF7L modulates brown adipose tissue formation

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Haiying Zhou ◽  
Bo Wan ◽  
Ivan Grubisic ◽  
Tommy Kaplan ◽  
Robert Tjian
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Core Promoter ◽  
Uncoupling Protein ◽  
Dna Looping ◽  
Chromatin Interactions ◽  
Brown Adipose ◽  
Important Regulator

Brown adipose tissue (BAT) plays an essential role in metabolic homeostasis by dissipating energy via thermogenesis through uncoupling protein 1 (UCP1). Previously, we reported that the TATA-binding protein associated factor 7L (TAF7L) is an important regulator of white adipose tissue (WAT) differentiation. In this study, we show that TAF7L also serves as a molecular switch between brown fat and muscle lineages in vivo and in vitro. In adipose tissue, TAF7L-containing TFIID complexes associate with PPARγ to mediate DNA looping between distal enhancers and core promoter elements. Our findings suggest that the presence of the tissue-specific TAF7L subunit in TFIID functions to promote long-range chromatin interactions during BAT lineage specification.

scholarly journals Dopamine receptor D1- and D2-agonists do not spark brown adipose tissue thermogenesis in mice

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Francesca-Maria Raffaelli ◽  
Julia Resch ◽  
Rebecca Oelkrug ◽  
K. Alexander Iwen ◽  
Jens Mittag
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Dopamine Receptor ◽  
Ex Vivo ◽  
Potential Target ◽  
D2 Agonist ◽  
Obesity And Diabetes ◽  
Brown Adipose

AbstractBrown adipose tissue (BAT) thermogenesis is considered a potential target for treatment of obesity and diabetes. In vitro data suggest dopamine receptor signaling as a promising approach; however, the biological relevance of dopamine receptors in the direct activation of BAT thermogenesis in vivo remains unclear. We investigated BAT thermogenesis in vivo in mice using peripheral administration of D1-agonist SKF38393 or D2-agonist Sumanirole, infrared thermography, and in-depth molecular analyses of potential target tissues; and ex vivo in BAT explants to identify direct effects on key thermogenic markers. Acute in vivo treatment with the D1- or D2-agonist caused a short spike or brief decrease in BAT temperature, respectively. However, repeated daily administration did not induce lasting effects on BAT thermogenesis. Likewise, neither agonist directly affected Ucp1 or Dio2 mRNA expression in BAT explants. Taken together, the investigated agonists do not seem to exert lasting and physiologically relevant effects on BAT thermogenesis after peripheral administration, demonstrating that D1- and D2-receptors in iBAT are unlikely to constitute targets for obesity treatment via BAT activation.

scholarly journals PPARγ regulates adipose triglyceride lipase in adipocytes in vitro and in vivo

2007 ◽  
Vol 293 (6) ◽  
pp. E1736-E1745 ◽  
Author(s):  
Erin E. Kershaw ◽  
Michael Schupp ◽  
Hong-Ping Guan ◽  
Noah P. Gardner ◽  
Mitchell A. Lazar ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Adipose Tissue ◽  
Lipid Metabolism ◽  
Protein Synthesis Inhibitor ◽  
Adipose Triglyceride Lipase ◽  
Dependent Manner ◽  
Triglyceride Lipase ◽  
Brown Adipose

Peroxisome proliferator-activated receptor-γ (PPARγ) regulates adipocyte genes involved in adipogenesis and lipid metabolism and is the molecular target for thiazolidinedione (TZD) antidiabetic agents. Adipose triglyceride lipase (ATGL) is a recently described triglyceride-specific lipase that is induced during adipogenesis and remains highly expressed in mature adipocytes. This study evaluates the ability of PPARγ to directly regulate ATGL expression in adipocytes in vitro and in vivo. In fully differentiated 3T3-L1 adipocytes, ATGL mRNA and protein are increased by TZD and non-TZD PPARγ agonists in a dose- and time-dependent manner. Rosiglitazone-mediated induction of ATGL mRNA is rapid and is not inhibited by the protein synthesis inhibitor cycloheximide, indicating that intervening protein synthesis is not required for this effect. Rosiglitazone-mediated induction of ATGL mRNA and protein is inhibited by the PPARγ-specific antagonist GW-9662 and is also significantly reduced following siRNA-mediated knockdown of PPARγ, supporting the direct transcriptional regulation of ATGL by PPARγ. In vivo, ATGL mRNA and protein are increased by rosiglitazone treatment in white and brown adipose tissue of mice with and without obesity due to high-fat diet or leptin deficiency. Thus, PPARγ positively regulates ATGL mRNA and protein expression in mature adipocytes in vitro and in adipose tissue in vivo, suggesting a role for ATGL in mediating PPARγ's effects on lipid metabolism.

scholarly journals Myostatin Attenuation In Vivo Reduces Adiposity, but Activates Adipogenesis

Endocrinology ◽  
2016 ◽  
Vol 157 (1) ◽  
pp. 282-291 ◽  
Author(s):  
Naisi Li ◽  
Qiyuan Yang ◽  
Ryan G. Walker ◽  
Thomas B. Thompson ◽  
Min Du ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Muscle Mass ◽  
Wild Type ◽  
Cell Counts ◽  
Novel Approach ◽  
Brown Adipose ◽  
Nutrient Partitioning ◽  
Differentiation Marker

Abstract A potentially novel approach for treating obesity includes attenuating myostatin as this increases muscle mass and decreases fat mass. Notwithstanding, conflicting studies report that myostatin stimulates or inhibits adipogenesis and it is unknown whether reduced adiposity with myostatin attenuation results from changes in fat deposition or adipogenesis. We therefore quantified changes in the stem, transit amplifying and progenitor cell pool in white adipose tissue (WAT) and brown adipose tissue (BAT) using label-retaining wild-type and mstn−/− (Jekyll) mice. Muscle mass was larger in Jekyll mice, WAT and BAT mass was smaller and label induction was equal in all tissues from both wild-type and Jekyll mice. The number of label-retaining cells, however, dissipated quicker in WAT and BAT of Jekyll mice and was only 25% and 17%, respectively, of wild-type cell counts 1 month after induction. Adipose cell density was significantly higher in Jekyll mice and increased over time concomitant with label-retaining cell disappearance, which is consistent with enhanced expansion and differentiation of the stem, transit amplifying and progenitor pool. Stromal vascular cells from Jekyll WAT and BAT differentiated into mature adipocytes at a faster rate than wild-type cells and although Jekyll WAT cells also proliferated quicker in vitro, those from BAT did not. Differentiation marker expression in vitro, however, suggests that mstn−/− BAT preadipocytes are far more sensitive to the suppressive effects of myostatin. These results suggest that myostatin attenuation stimulates adipogenesis in vivo and that the reduced adiposity in mstn−/− animals results from nutrient partitioning away from fat and in support of muscle.

Overexpression of a short human seipin/BSCL2 isoform in mouse adipose tissue results in mild lipodystrophy

2012 ◽  
Vol 302 (6) ◽  
pp. E705-E713 ◽  
Author(s):  
Xin Cui ◽  
Yuhui Wang ◽  
Lingjun Meng ◽  
Weihua Fei ◽  
Jingna Deng ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Transgenic Mice ◽  
White Adipose Tissue ◽  
Loss Of Function ◽  
Gene Encoding ◽  
Triacylglycerol Content ◽  
Adipocyte Development

Berardinelli-Seip congenital lipodystrophy type 2 (BSCL2) is a recessive disorder characterized by an almost complete loss of adipose tissue, insulin resistance, and fatty liver. BSCL2 is caused by loss-of-function mutations in the BSCL2/seipin gene, which encodes seipin. The essential role for seipin in adipogenesis has recently been established both in vitro and in vivo. However, seipin is highly upregulated at later stages of adipocyte development, and its role in mature adipocytes remains to be elucidated. We therefore generated transgenic mice overexpressing a short isoform of human BSCL2 gene (encoding 398 amino acids) using the adipocyte-specific aP2 promoter. The transgenic mice produced ∼150% more seipin than littermate controls in white adipose tissue. Surprisingly, the increased expression of seipin markedly reduced the mass of white adipose tissue and the size of adipocytes and lipid droplets. This may be due in part to elevated lipolysis rates in the transgenic mice. Moreover, there was a nearly 50% increase in the triacylglycerol content of transgenic liver. These results suggest that seipin promotes the differentiation of preadipocytes but may inhibit lipid storage in mature adipocytes.

scholarly journals Enhanced angiogenesis in obesity and in response to PPARγ activators through adipocyte VEGF and ANGPTL4 production

2008 ◽  
Vol 295 (5) ◽  
pp. E1056-E1064 ◽  
Author(s):  
Olga Gealekman ◽  
Alison Burkart ◽  
My Chouinard ◽  
Sarah M. Nicoloro ◽  
Juerg Straubhaar ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Endothelial Cell ◽  
Cell Growth ◽  
Tissue Mass ◽  
Adipose Tissue Mass ◽  
Cell Growth And Differentiation ◽  
Endothelial Cell Growth ◽  
Sprout Formation

PPARγ activators such as rosiglitazone (RSG) stimulate adipocyte differentiation and increase subcutaneous adipose tissue mass. However, in addition to preadipocyte differentiation, adipose tissue expansion requires neovascularization to support increased adipocyte numbers. Paradoxically, endothelial cell growth and differentiation is potently inhibited by RSG in vitro, raising the question of how this drug can induce an increase in adipose tissue mass while inhibiting angiogenesis. We find that adipose tissue from mice treated with RSG have increased capillary density. To determine whether adipose tissue angiogenesis was stimulated by RSG, we developed a novel assay to study angiogenic sprout formation ex vivo. Angiogenic sprout formation from equally sized adipose tissue fragments, but not from aorta rings, was greatly increased by obesity and by TZD treatment in vivo. To define the mechanism involved in RSG-stimulated angiogenesis in adipose tissue, the expression of proangiogenic factors by adipocytes was examined. Expression of VEGFA and VEGFB, as well as of the angiopoietin-like factor-4 (ANGPTL4), was stimulated by in vivo treatment with RSG. To define the potential role of these factors, we analyzed their effects on endothelial cell growth and differentiation in vitro. We found that ANGPTL4 stimulates endothelial cell growth and tubule formation, albeit more weakly than VEGF. However, ANGPTL4 mitigates the growth inhibitory actions of RSG on endothelial cells in the presence or absence of VEGF. Thus, the interplay between VEGF and ANGPTL4 could lead to a net expansion of the adipose tissue capillary network, required for adipose tissue growth, in response to PPARγ activators.

scholarly journals Expression of peroxisome proliferator-activated receptors in lean and obese Zucker rats

2000 ◽  
pp. 71-78 ◽  
Author(s):  
A Gorla-Bajszczak ◽  
C Siegrist-Kaiser ◽  
O Boss ◽  
AG Burger ◽  
CA Meier
Keyword(s):  
Adipose Tissue ◽  
Fiber Type ◽  
Zucker Rats ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Rnase Protection ◽  
Brown Adipose ◽  
Obese Zucker Rats

OBJECTIVE: Examination of the pattern of expression of peroxisome proliferator-activated receptor (PPAR) isoforms alpha and gamma in a model of obesity. DESIGN: Examination of adipose tissue and primary adipocyte cultures from lean and obese Zucker rats at different ages (28 days and 12 weeks). METHODS: mRNA levels were measured by RNase protection assay.RESULTS: The highest levels of PPARalpha and gamma mRNA were present in brown adipose tissue (BAT), followed by liver and white adipose tissue (WAT) for the alpha and gamma subtypes, respectively, at both ages examined. PPARalpha was expressed 100-fold higher in BAT compared with WAT, and PPARgamma mRNA levels were 2-fold higher in the WAT of obese compared with lean rats. PPARalpha and gamma expression was minimal in m. soleus, although higher levels of PPARgamma were found in the diaphragm. In marked contrast to the findings in vivo, virtually no PPARalpha mRNA could be detected in BAT cultures differentiated in vitro. CONCLUSION: PPARalpha and gamma are most highly expressed in BAT in vivo. However, PPARalpha is undetectable in brown adipose cells in vitro, suggesting that the expression of this receptor is induced by some external stimuli. In addition, the expression of PPARgamma was increased in WAT from young obese animals, compatible with an early adaptive phenomenon. Finally, the presence of PPARgamma mRNA is detectable only in particular muscles, such as the diaphragm, suggesting the possibility of an influence of fiber type on its expression, although exercise did not influence the expression of PPARgamma in other skeletal muscles.

scholarly journals Long noncoding RNA GAS5 inhibits progression of colorectal cancer by interacting with and triggering YAP phosphorylation and degradation and is negatively regulated by the m6A reader YTHDF3

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Wen Ni ◽  
Su Yao ◽  
Yunxia Zhou ◽  
Yuanyuan Liu ◽  
Piao Huang ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cancer Progression ◽  
Noncoding Rna ◽  
Function Analysis ◽  
Loss Of Function ◽  
Functional Link ◽  
Protein Levels ◽  
Lncrna Gas5

Abstract Background YAP activation is crucial for cancer development including colorectal cancer (CRC). Nevertheless, it remains unclear whether N6-Methyladenosine (m6A) modified transcripts of long noncoding RNAs (lncRNAs) can regulate YAP activation in cancer progression. We investigated the functional link between lncRNAs and the m6A modification in YAP signaling and CRC progression. Methods YAP interacting lncRNAs were screened by RIP-sequencing, RNA FISH and immunofluorescence co-staining assays. Interaction between YAP and lncRNA GAS5 was studied by biochemical methods. MeRIP-sequencing combined with lncRNA-sequencing were used to identify the m6A modified targets of YTHDF3 in CRC. Gain-of-function and Loss-of-function analysis were performed to measure the function of GAS5-YAP-YTHDF3 axis in CRC progression in vitro and in vivo. Results GAS5 directly interacts with WW domain of YAP to facilitate translocation of endogenous YAP from the nucleus to the cytoplasm and promotes phosphorylation and subsequently ubiquitin-mediated degradation of YAP to inhibit CRC progression in vitro and in vivo. Notably, we demonstrate the m6A reader YTHDF3 not only a novel target of YAP but also a key player in YAP signaling by facilitating m6A-modified lncRNA GAS5 degradation, which profile a new insight into CRC progression. Clinically, lncRNA GAS5 expressions is negatively correlated with YAP and YTHDF3 protein levels in tumors from CRC patients. Conclusions Our study uncovers a negative functional loop of lncRNA GAS5-YAP-YTHDF3 axis, and identifies a new mechanism for m6A-induced decay of GAS5 on YAP signaling in progression of CRC which may offer a promising approach for CRC treatment.

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