scholarly journals Nutritional status induces divergent variations of GLUT4 protein content, but not lipoprotein lipase activity, between adipose tissues and muscles in adult cattle

2004 ◽  
Vol 92 (4) ◽  
pp. 617-625 ◽  
Author(s):  
Muriel Bonnet ◽  
Yannick Faulconnier ◽  
Jean-François Hocquette ◽  
François Bocquier ◽  
Christine Leroux ◽  
...  

Metabolic adaptations to variations in food supply are incompletely understood in ruminant animal adipose tissue (AT) and muscle. To explore this, we studied lipid metabolism and glucose transport potential in one internal and one external AT, as well as in one oxidative and one glycolytic muscle from control, 7 d underfed and 21 d refed adult cows. Refeeding increased (+79 to +307 %) the activities of enzymes involved in de novo lipogenesis (fatty acid synthase, malic enzyme, glucose-6-phosphate dehydrogenase) in perirenal and subcutaneous AT; underfeeding did not modify these variables. Underfeeding decreased the activities of lipoprotein lipase (LPL) in perirenal AT (−70 %) and cardiac muscle (−67 %), but did not modify the activities in subcutaneous AT and longissimus thoracis. Refeeding increased LPL activities in all tissues (+40 to +553 %) to levels comparable with (cardiac muscle) or greater than (AT, longissimus thoracis) those observed in control cows. Such variations in perirenal and cardiac muscle LPL activities did not result from variations in LPL mRNA levels, but suggest a post-transcriptional regulation of LPL in these nutritional conditions. Underfeeding did not modify GLUT4 contents in perirenal AT and muscles, while refeeding increased it only in perirenal AT (+250 %). Our present results contrast with previous results in rats, where LPL is regulated in opposite directions in AT and muscles, and GLUT4 is generally increased by fasting and decreased by refeeding in skeletal muscles. The present results highlight the bovine specificity of the response, which probably arises in part from peculiarities of ruminant animals for nutrient digestion and absorption.

2001 ◽  
Vol 85 (3) ◽  
pp. 299-306 ◽  
Author(s):  
Y. Faulconnier ◽  
M. Bonnet ◽  
F. Bocquier ◽  
C. Leroux ◽  
Y. Chilliard

The aim of the present study was to investigate the effects of photoperiod and feeding level on lipid metabolism in ovine perirenal and subcutaneous adipose tissues (AT) and in skeletal and cardiac muscles. Twenty dry non-pregnant ovariectomised ewes were divided into two groups and subjected to either 8 h or 16 h light/d, and underfed at 22 % energy requirements for 7 d. Half of the ewes in each group were slaughtered and the remaining ewes were refed at 190 % energy requirements for 14 d, until slaughtering. Refeeding increased (2.6–4.3-fold) malic enzyme (ME), fatty acid synthase (FAS), glucose-6-phosphate dehydrogenase (G6PDH) and glycerol-3-phosphate dehydrogenase (G3PDH) activities in subcutaneous AT as well as lipoprotein lipase (LPL) activity in perirenal (3.5-fold) and subcutaneous (10-fold) AT and to a lesser extent (1.4-fold) in the skeletal longissimus thoracis and cardiac muscles. Moreover, variations of LPL mRNA level followed variations of LPL activity: refeeding increased perirenal AT- and cardiac muscle-mRNA levels (7.4- and 2-fold respectively). The main finding of this study is that, for a given level of food intake, long days (compared with short days) increased the LPL activity in the longissimus thoracis muscle and, in refed ewes, the activities of LPL and ME in subcutaneous AT. Furthermore, long days increased LPL mRNA level in cardiac muscle and perirenal AT. Thus, our results show that there are direct effects of photoperiod on sheep AT lipogenic potential, as well as on muscle LPL activity, which are not caused by changes in nutrient availability.


2017 ◽  
Vol 118 (8) ◽  
pp. 570-579 ◽  
Author(s):  
Guang-Hui Chen ◽  
Christer Hogstrand ◽  
Zhi Luo ◽  
Dian-Guang Zhang ◽  
Shi-Cheng Ling ◽  
...  

AbstractThe present study explored the mechanisms of dietary Zn influencing Zn and lipid deposition in the fore- and mid- intestine in yellow catfishPelteobagrus fulvidraco, and investigated whether the mechanism was intestinal-region dependent. For this purpose, yellow catfish were fed three diets containing Zn levels of 8·83, 19·20 and 146·65 mg Zn/kg, respectively. Growth performance, intestinal TAG and Zn contents as well as activities and mRNA expression of enzymes and genes involved in Zn transport and lipid metabolism in the fore- and mid-intestine were analysed. Dietary Zn increased Zn accumulation as well as activities of Cu-, Zn-superoxide dismutase and ATPase in the fore- and mid-intestine. In the fore-intestine, dietary Zn up-regulated mRNA levels of ZnT1, ZnT5, ZnT7, metallothionein (MT) and metal response element-binding transcription factor-1 (MTF-1), but down-regulated mRNA levels of ZIP4 and ZIP5. In the mid-intestine, dietary Zn up-regulated mRNA levels of ZnT1, ZnT5, ZnT7, MT and MTF-1, but down-regulated mRNA levels of ZIP4 and ZIP5. Dietary Zn reduced TAG content, down-regulated activities of 6-phosphogluconate dehydrogenase (6PGD), glucose-6-phosphate dehydrogenase (G6PD), malic enzyme (ME) and fatty acid synthase (FAS) activities, and reduced mRNA levels of 6PGD, G6PD, FAS, PPARγand sterol-regulator element-binding protein (SREBP-1), but up-regulated mRNA levels of carnitine palmitoyltransferase IA, hormone-sensitive lipase (HSLa), adipose TAG lipase (ATGL) and PPARαin the fore-intestine. In the mid-intestine, dietary Zn reduced TAG content, activities of G6PD, ME, isocitrate dehydrogenase and FAS, down-regulated mRNA levels of 6PGD, G6PD, FAS, acetyl-CoA carboxylase a, PPARγand SREBP-1, but up-regulated mRNA expression of HSLa, ATGL and PPARγ. The reduction in TAG content following Zn addition was attributable to reduced lipogenesis and increased lipolysis, and similar regulatory mechanisms were observed between the fore- and mid-intestine.


1994 ◽  
Vol 267 (2) ◽  
pp. L128-L136
Author(s):  
J. Rami ◽  
W. Stenzel ◽  
S. M. Sasic ◽  
C. Puel-M'Rini ◽  
J. P. Besombes ◽  
...  

Silica instillation causes a massive increase in lung surfactant. Two populations of type II pneumocytes can be isolated from rats administered silica by intratracheal injection: type IIA cells similar to type II cells from normal rats and type IIB cells, which are larger and contain elevated levels of surfactant protein A and phospholipid. Activities of choline-phosphate cytidylyltransferase, a rate-regulatory enzyme in phosphatidylcholine biosynthesis, and fatty-acid synthase (FAS) are increased in type IIB cells isolated from rats 14 days after silica injection. In the present study, we examined the increase in FAS and cytidylyltransferase activities in type IIB cells as a function of time after silica administration. FAS activity increased rapidly, was approximately threefold elevated 1 day after silica administration and has reached close to the maximum increase by 3 days. Cytidylyltransferase activity was not increased on day 1, was significantly increased on day 3 but was not maximally increased until day 7. Inhibition of de novo fatty-acid biosynthesis, by in vivo injection of hydroxycitric acid and inclusion of agaric acid in the type II cell culture medium, abolished the increase in cytidylyltransferase activity on day 3 but not FAS and had no effect on activities of two other enzymes of phospholipid synthesis. FAS mRNA levels were not increased in type IIB cells isolated 1-14 days after silica injection. These data show that the increase in FAS activity in type IIB cells is an early response to silica, that it mediates the increase in cytidylyltransferase activity, and that it is not due to enhanced FAS gene expression.


2006 ◽  
Vol 27 (2) ◽  
pp. 131-140 ◽  
Author(s):  
Yun Wang ◽  
Kevin Seburn ◽  
Lawrence Bechtel ◽  
Bruce Y. Lee ◽  
Jin P. Szatkiewicz ◽  
...  

Tub is a member of a small gene family, the tubby-like proteins (TULPs), with predominant expression in neurons. Mice carrying a mutation in Tub develop retinal and cochlear degeneration as well as late-onset obesity with insulin resistance. During behavioral and metabolic testing, we found that homozygous C57BL/6J- Tub tub mice have a lower respiratory quotient than C57BL/6J controls before the onset of obesity, indicating that tubby homozygotes fail to activate carbohydrate metabolism and instead rely on fat metabolism for energy needs. In concordance with this, tubby mice show higher excretion of ketone bodies and accumulation of glycogen in the liver. Quantitation of liver mRNA levels shows that, during the transition from light to dark period, tubby mice fail to induce glucose-6-phosphate dehydrogenase ( G6pdh), the rate-limiting enzyme in the pentose phosphate pathway that normally supplies NADPH for de novo fatty acid synthesis and glutathione reduction. Reduced G6PDH protein levels and enzymatic activity in tubby mice lead accordingly to lower levels of NADPH and reduced glutathione (GSH), respectively. mRNA levels for the lipolytic enzymes acetyl-CoA synthetase and carnitine palmitoyltransferase are increased during the dark cycle and decreased during the light period, and several citric acid cycle genes are dysregulated in tubby mice. Examination of hypothalamic gene expression showed high levels of preproorexin mRNA leading to accumulation of orexin peptide in the lateral hypothalamus. We hypothesize that abnormal hypothalamic orexin expression leads to changes in liver carbohydrate metabolism and may contribute to the moderate obesity observed in tubby mice.


2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1652-1652
Author(s):  
Yoojin Lee ◽  
Minkyung Bae ◽  
Dana Chamberlain ◽  
Tho Pham ◽  
Hyunju Kang ◽  
...  

Abstract Objectives Evidence suggests that histone deacetylase 4 (HDAC4) is downregulated in adipose tissue of obese subjects. We determined the role of HDAC4 in the regulation of energy metabolism of metabolically active tissues, such as the liver and adipose tissue. Methods Hepatocyte-specific (Hdac4HKO) and adipocyte-specific (Hdac4AKO) Hdac4 knockout mice were generated by crossing homozygous Hdac4 floxed (Hdac4fl/fl) mice with mice expressing Cre recombinase under the control of the enhancer/promoter of Albumin or Adipoq gene, respectively. Hdac4fl/fl and Hdac4HKO mice were fed a high fat/high sucrose (HF/HS; 57%/28% energy from fat/sucrose) with 2% cholesterol (w/w) diet for 16 weeks. Hdac4fl/fl and Hdac4AKO mice were fed an obesogenic HF/HS diet for 16 weeks. The final serum was collected by cardiopuncture for blood analysis. Tissues were snap frozen for mRNA and protein analysis. Results Both Hdac4HKO and Hdac4AKO mice did not show differences in body weight compared to Hdac4fl/fl mice following the 16-week of experimental diet. However, loss of hepatic HDAC4 increased serum alanine transaminase levels, a marker for liver injury. Also, Hdac4HKO mice had exacerbated hepatic steatosis with higher liver weights and triglyceride levels than Hdac4fl/fl mice. Consistently, hepatic expression of genes for de novo lipogenesis, including Srebf1c and its target genes, fatty acid synthase and acetyl CoA carboxylase 1, was significantly higher in Hdac4HKO mice compared with control mice. Interestingly, the loss of hepatocyte HDAC4 aggravated inflammation and fibrosis in white adipose tissue. Serum cytokine array indicated increases in fibroblast growth factor 1, pentraxin 3, tissue inhibitor of metalloproteinases 1, and decrease in endocan, which may contribute to the crosstalk between the liver and adipose tissue in Hdac4HKO. On the other hand, the loss of adipocyte HDAC4 elicited minimal changes in mRNA levels of lipogenic, inflammatory, and fibrogenic genes in adipose tissue and the liver. Conclusions The lack of functional hepatocyte HDAC4 increased lipid accumulation in the liver of obesity mice via increasing hepatic de novo lipogenesis, and also aggravated adipose tissue inflammation and fibrosis. Further investigation is warranted to elucidate the crosstalk between the liver and adipose tissue in Hdac4HKO. Funding Sources This study was supported by NIH.


2008 ◽  
Vol 100 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Doan Thi Thanh Huong ◽  
Takashi Ide

Effects of dietary α-lipoic acid on hepatic and serum lipid concentrations and the activity and mRNA levels of lipogenic enzymes were examined in rats. Rats were fed experimental diets containing varying amounts of lipoic acid (0, 1, 2·5, 5 g/kg) for 21 d. Lipoic acid profoundly decreased serum and liver concentrations of TAG, and also lowered serum concentrations of phospholipid and NEFA, and the concentration of cholesterol in the liver. A hypoglycaemic effect of this compound was also observed. Lipoic acid dose-dependently decreased the activity and mRNA levels of fatty acid synthase, ATP-citrate lyase, glucose 6-phosphate dehydrogenase, malic enzyme and pyruvate kinase in the liver despite that reductions were considerably attenuated in the NADPH-producing enzymes. This compound also dose-dependently lowered the mRNA levels of spot 14, adiponutrin, stearoyl-CoA desaturase 1, and Δ5- and Δ6-desaturases. In addition, lipoic acid dose-dependently lowered serum concentrations of insulin and leptin, but increased those of adiponectin. Lipoic acid appeared to reduce hepatic lipogenesis and hence decreases serum and liver lipid levels. Alterations in serum concentrations of insulin and (or) adiponectin may trigger this consequence.


Author(s):  
Magali Humbert ◽  
Kristina Seiler ◽  
Severin Mosimann ◽  
Vreni Rentsch ◽  
Katyayani Sharma ◽  
...  

AbstractFatty acid synthase (FASN) is the only human lipogenic enzyme available for de novo fatty acid synthesis and is often highly expressed in cancer cells. We found that FASN mRNA levels were significantly higher in acute myeloid leukemia (AML) patients than in healthy granulocytes or CD34+ hematopoietic progenitors. Accordingly, FASN levels decreased during all-trans retinoic acid (ATRA)-mediated granulocytic differentiation of acute promyelocytic leukemia (APL) cells, partially via autophagic degradation. Furthermore, our data suggest that inhibition of FASN expression levels using RNAi or (-)-epigallocatechin-3-gallate (EGCG) accelerated the differentiation of APL cell lines and significantly re-sensitized ATRA refractory non-APL AML cells. FASN reduction promoted translocation of transcription factor EB (TFEB) to the nucleus, paralleled by activation of CLEAR network genes and lysosomal biogenesis. Together, our data demonstrate that inhibition of FASN expression in combination with ATRA treatment facilitates granulocytic differentiation of APL cells and may extend differentiation therapy to non-APL AML cells.


2005 ◽  
Vol 389 (2) ◽  
pp. 413-421 ◽  
Author(s):  
Brian L. Knight ◽  
Abdel Hebbachi ◽  
David Hauton ◽  
Anna-Marie Brown ◽  
David Wiggins ◽  
...  

Inclusion of the PPARα (peroxisome-proliferator-activated receptor α) activator WY 14,643 in the diet of normal mice stimulated the hepatic expression of not only genes of the fatty acid oxidation pathway, but also those of the de novo lipid synthetic pathways. Induction of fatty acid synthase mRNA by WY 14,643 was greater during the light phase of the diurnal cycle, when food intake was low and PPARα expression was high. Hepatic fatty acid pathway flux in vivo showed a similar pattern of increases. The abundance of mRNAs for genes involved in hepatic cholesterol synthesis was also increased by WY 14,643, but was associated with a decrease in cholesterogenic carbon flux. None of these changes were apparent in PPARα-null mice. Mice of both genotypes showed the expected decreases in 3-hydroxy-3-methylglutaryl-CoA reductase mRNA levels and cholesterol synthesis in response to an increase in dietary cholesterol. The increase in fatty acid synthesis due to WY 14,643 was not mediated by increased expression of SREBP-1c (sterol regulatory element binding protein-1c) mRNA, but by an increase in cleavage of the protein to the active form. An accompanying rise in stearoyl-CoA desaturase mRNA expression suggested that the increase in lipogenesis could have resulted from an alteration in membrane fatty acid composition that influenced SREBP activation.


Author(s):  
Magali Humbert ◽  
Kristina Seiler ◽  
Severin Mosimann ◽  
Vreni Rentsch ◽  
Sharon L. McKenna ◽  
...  

AbstractFatty acid synthase (FASN) is the only human lipogenic enzyme available for de novo fatty acid synthesis and is often highly expressed in cancer cells. We found that FASN mRNA levels were significantly higher in acute myeloid leukemia (AML) patients than in healthy granulocytes or CD34+ hematopoietic progenitors. Accordingly, FASN levels decreased during all-trans retinoic acid (ATRA)-mediated granulocytic differentiation of acute promyelocytic leukemia (APL) cells, partially via autophagic degradation. Furthermore, our data suggests that inhibition of FASN expression levels using RNAi or (-)-epigallocatechin-3-gallate (EGCG), accelerates the differentiation of APL cell lines and significantly re-sensitized ATRA refractory non-APL AML cells. FASN reduction promoted translocation of transcription factor EB (TFEB) to the nucleus, paralleled by activation of CLEAR network genes and lysosomal biogenesis. Lysosomal biogenesis was activated, consistent with TFEB transcriptional activation of CLEAR network genes.Together, our data demonstrate that inhibition of FASN expression in combination with ATRA treatment facilitates granulocytic differentiation of APL cells and may extend differentiation therapy to non-APL AML cells.


1996 ◽  
Vol 270 (1) ◽  
pp. E192-E196 ◽  
Author(s):  
B. H. Jones ◽  
J. H. Kim ◽  
M. B. Zemel ◽  
R. P. Woychik ◽  
E. J. Michaud ◽  
...  

Mutations leading to ectopic expression of the murine agouti gene (a) result in progressive obesity. To further characterize this model, we analyzed adipose and hepatic mRNA levels for fatty acid synthase (FAS) and stearoyl-CoA desaturase (SCD), two key enzymes in de novo fatty acid synthesis and desaturation, respectively. FAS and SCD mRNA in both tissues of obese (Avy) mice were dramatically increased relative to lean (ala) controls. Excessive expression of these genes in this model could be due to direct effects of the agouti gene product; to test this possibility we treated 3T3-L1 adipocytes in vitro with recombinant agouti protein. Agouti treatment increased FAS and SCD mRNA levels by 1.5- and 4-fold, respectively. In addition, FAS activity and triglyceride content were 3-fold higher in agoutitreated 3T3-L1 cells relative to controls; these effects were attenuated by simultaneous treatment with a calcium channel blocker (nitrendipine). These data demonstrate that the agouti protein can directly increase lipogenesis in adipocytes and suggest that these effects are mediated through an intracellular calcium-dependent mechanism.


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