Targeting Ketohexokinase (KHK) with a Novel Antisense Oligonucleotide (ASO) Decreases De Novo Lipogenesis and Improves Insulin-Mediated Whole Body Glucose Metabolism

Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 149-OR ◽  
Author(s):  
DONGQING LIU ◽  
JOHN A. STERPKA ◽  
DANIEL F. VATNER ◽  
MELANIE BELL ◽  
SUE MURRAY ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Antisense Oligonucleotide ◽  
De Novo ◽  
De Novo Lipogenesis ◽  
Whole Body

Effect of carbohydrate intake on de novo lipogenesis in human adipose tissue

1987 ◽  
Vol 253 (6) ◽  
pp. E664-E669 ◽  
Author(s):  
C. Chascione ◽  
D. H. Elwyn ◽  
M. Davila ◽  
K. M. Gil ◽  
J. Askanazi ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
De Novo ◽  
Acid Synthesis ◽  
De Novo Lipogenesis ◽  
Whole Body ◽  
High Intake ◽  
Carbohydrate Diet ◽  
Triglyceride Synthesis ◽  
High Carbohydrate

Rates of synthesis, from [14C]glucose, of fatty acids (de novo lipogenesis) and glycerol (triglyceride synthesis) were measured in biopsies of adipose tissue from nutritionally depleted patients given low- or high-carbohydrate intravenous nutrition. Simultaneously, energy expenditure and whole-body lipogenesis were measured by indirect calorimetry. Rates of whole-body lipogenesis were zero on the low-carbohydrate diet and averaged 1.6 g.kg-1.day-1 on the high-carbohydrate diet. In vitro rates of triglyceride synthesis increased 3-fold going from the low to the high intake; rates of fatty acid synthesis increased approximately 80-fold. In vitro, lipogenesis accounted for less than 0.1% of triglyceride synthesis on the low intake and 4% on the high intake. On the high-carbohydrate intake, in vitro rates of triglyceride synthesis accounted for 61% of the rates of unidirectional triglyceride synthesis measured by indirect calorimetry. In vitro rates of lipogenesis accounted for 7% of whole-body lipogenesis. Discrepancies between in vitro rates of fatty acid synthesis from glucose, compared with acetate and citrate, as reported by others, suggest that in depleted patients on hypercaloric high-carbohydrate diets, adipose tissue may account for up to 40% of whole-body lipogenesis.

scholarly journals MAPK-interacting kinase 2 (MNK2) regulates adipocyte metabolism independently of its catalytic activity

2020 ◽  
Vol 477 (14) ◽  
pp. 2735-2754
Author(s):  
James E. Merrett ◽  
Jianling Xie ◽  
Peter J. Psaltis ◽  
Christopher G. Proud
Keyword(s):  
Catalytic Activity ◽  
Lipid Accumulation ◽  
Adipocyte Differentiation ◽  
De Novo ◽  
Lipid Storage ◽  
De Novo Lipogenesis ◽  
Hormone Sensitive Lipase ◽  
Mitogen Activated Protein Kinase ◽  
Whole Body ◽  
Knock Down

The mitogen-activated protein kinase (MAPK)-interacting kinases (MNKs) are serine/threonine protein kinases that are activated by the ERK1/2 (extracellular regulated kinase) and p38α/β MAPK pathways. The MNKs have previously been implicated in metabolic disease and shown to mediate diet-induced obesity. In particular, knockout of MNK2 in mice protects from the weight gain induced by a high-fat diet. These and other data suggest that MNK2 regulates the expansion of adipose tissue (AT), a stable, long-term energy reserve that plays an important role in regulating whole-body energy homeostasis. Using the well-established mouse 3T3-L1 in vitro model of adipogenesis, the role of the MNKs in adipocyte differentiation and lipid storage was investigated. Inhibition of MNK activity using specific inhibitors failed to impair adipogenesis or lipid accumulation, suggesting that MNK activity is not required for adipocyte differentiation and does not regulate lipid storage. However, small-interfering RNA (siRNA) knock-down of MNK2 did reduce lipid accumulation and regulated the levels of two major lipogenic transcriptional regulators, ChREBP (carbohydrate response element-binding protein) and LPIN1 (Lipin-1). These factors are responsible for controlling the expression of genes for proteins involved in de novo lipogenesis and triglyceride synthesis. The knock-down of MNK2 also increased the expression of hormone-sensitive lipase which catalyses the breakdown of triglyceride. These findings identify MNK2 as a regulator of adipocyte metabolism, independently of its catalytic activity, and reveal some of the mechanisms by which MNK2 drives AT expansion. The development of an MNK2-targeted therapy may, therefore, be a useful intervention for reducing weight caused by excessive nutrient intake.

scholarly journals SUN-LB52 The Protective Effects of Hepatocyte GH Receptor (GHR) Signaling Against Steatosis and Liver Injury Is Sexually Dimorphic and Autonomous of IGF1

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Andre Sarmento-Cabral ◽  
Mercedes del Rio-Moreno ◽  
Mari C Vazquez-Borrego ◽  
Mariyah Mahmood ◽  
Elena Gutierrez-Casado ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Liver Injury ◽  
Fatty Liver ◽  
Negative Feedback ◽  
De Novo ◽  
De Novo Lipogenesis ◽  
Whole Body ◽  
Chow Diet ◽  
Alcoholic Fatty Liver ◽  
Systemic Insulin Resistance

Abstract GH dysregulation contributes to the development of non-alcoholic fatty liver disease (NAFLD), however debate remains as to the relative contribution of the direct vs indirect effects of GH, via IGF1. Mouse models with congenital, liver-specific knockout of the GHR, JAK2 or STAT5, as adults exhibit steatosis, glucose intolerance, insulin resistance and white adipose tissue (WAT) lipolysis. It is believed that fatty liver is due to the dramatic reduction in circulating IGF1 altering systemic metabolism, due to loss of the insulin-like effects of IGF1 and the loss of IGF1 negative feedback to the pituitary leading to a rise in GH that promotes systemic insulin resistance and WAT lipolysis shifting the flux of fatty acids to the liver. In addition, low IGF1/high GH alters the development of other metabolically relevant tissues, which could indirectly contribute to the liver phenotype observed with congenital loss of hepatic GH signaling. To directly test the actions of GH on adult hepatocyte function, we developed a mouse model of adult-onset, hepatocyte-specific knockdown of the GHR (aHepGHRkd; 12 week-old, GHRfl/fl mice treated with AAV8-TBGp-Cre). aHepGHRkd enhanced hepatic de novo lipogenesis (DNL), rapidly leading to steatosis in males, but not females. In males, enhanced DNL and steatosis was sustained with age and associated with hepatocyte ballooning, inflammation and mild fibrosis. These changes occurred independent of severe systemic insulin resistance and WAT lipolysis, although the aHepGHRkd mice exhibit low IGF1/high GH similar to that of congenital models. To directly test the role of hepatocyte GHR signaling, independent of changes in IGF1, aHepGHRkd mice were treated with a vector expressing rat IGF1 targeted specifically to hepatocytes (AAV8-TBGp-rIGF1). Mice were fed standard chow diet and tissues collected 8m post-AAV. IGF1 replacement elevated plasma IGF1 in aHepGHRkd mice, resulting in a reduction in plasma GH and pituitary expression of Gh, Ghrhr and Ghsr, indicating negative feedback of IGF1 was restored. In male aHepGHRkd mice, IGF1 replacement reduced insulin and whole body lipid utilization and increased WAT, however it did not reduce steatosis or alter hepatic fatty acid composition indicative of DNL and had minimal effects on liver injury markers. RNAseq analysis of liver extracts showed IGF1 replacement also had no major impact on the differentially expressed genes observed after aHepGHRkd. These results demonstrate that steatosis, DNL and liver injury observed in male aHepGHRkd mice are autonomous of IGF1. Despite the fact that hepatic GHR protein levels were not detectable in both female and male aHepGHRkd mice, females maintained moderate levels of IGF1 and were protected from steatosis. The mechanism by which female mice are protected remains to be elucidated, however is consistent with clinical data indicating pre-menopausal women are resistance to NAFLD.

scholarly journals Glucose-6 Phosphate, a Central Hub for Liver Carbohydrate Metabolism

Metabolites ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 282 ◽  
Author(s):  
Fabienne Rajas ◽  
Amandine Gautier-Stein ◽  
Gilles Mithieux
Keyword(s):  
Glucose Metabolism ◽  
Metabolic Diseases ◽  
De Novo ◽  
Glycogen Synthesis ◽  
Metabolic Reprogramming ◽  
De Novo Lipogenesis ◽  
Type I ◽  
Alcoholic Fatty Liver ◽  
Hexosamine Pathway

Cells efficiently adjust their metabolism according to the abundance of nutrients and energy. The ability to switch cellular metabolism between anabolic and catabolic processes is critical for cell growth. Glucose-6 phosphate is the first intermediate of glucose metabolism and plays a central role in the energy metabolism of the liver. It acts as a hub to metabolically connect glycolysis, the pentose phosphate pathway, glycogen synthesis, de novo lipogenesis, and the hexosamine pathway. In this review, we describe the metabolic fate of glucose-6 phosphate in a healthy liver and the metabolic reprogramming occurring in two pathologies characterized by a deregulation of glucose homeostasis, namely type 2 diabetes, which is characterized by fasting hyperglycemia; and glycogen storage disease type I, where patients develop severe hypoglycemia during short fasting periods. In these two conditions, dysfunction of glucose metabolism results in non-alcoholic fatty liver disease, which may possibly lead to the development of hepatic tumors. Moreover, we also emphasize the role of the transcription factor carbohydrate response element-binding protein (ChREBP), known to link glucose and lipid metabolisms. In this regard, comparing these two metabolic diseases is a fruitful approach to better understand the key role of glucose-6 phosphate in liver metabolism in health and disease.

scholarly journals Revealing Alteration in the Hepatic Glucose Metabolism of Genetically Improved Carp, Jayanti Rohu Labeo rohita Fed a High Carbohydrate Diet Using Transcriptome Sequencing

2020 ◽  
Vol 21 (21) ◽  
pp. 8180
Author(s):  
Kiran D. Rasal ◽  
Mir Asif Iquebal ◽  
Sangita Dixit ◽  
Manohar Vasam ◽  
Mustafa Raza ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Transcriptome Sequencing ◽  
De Novo ◽  
Glycogen Synthase ◽  
Labeo Rohita ◽  
De Novo Lipogenesis ◽  
Fish Diet ◽  
High Carbohydrate ◽  
Genetically Improved ◽  
Carbohydrate Levels

Although feed cost is the greatest concern in aquaculture, the inclusion of carbohydrates in the fish diet, and their assimilation, are still not well understood in aquaculture species. We identified molecular events that occur due to the inclusion of high carbohydrate levels in the diets of genetically improved ‘Jayanti rohu’ Labeo rohita. To reveal transcriptional changes in the liver of rohu, a feeding experiment was conducted with three doses of gelatinized starch (20% (control), 40%, and 60%). Transcriptome sequencing revealed totals of 15,232 (4464 up- and 4343 down-regulated) and 15,360 (4478 up- and 4171 down-regulated) differentially expressed genes. Up-regulated transcripts associated with glucose metabolisms, such as hexokinase, PHK, glycogen synthase and PGK, were found in fish fed diets with high starch levels. Interestingly, a de novo lipogenesis mechanism was found to be enriched in the livers of treated fish due to up-regulated transcripts such as FAS, ACCα, and PPARγ. The insulin signaling pathways with enriched PPAR and mTOR were identified by Kyoto Encyclopedia of Genes and Genome (KEGG) as a result of high carbohydrates. This work revealed for the first time the atypical regulation transcripts associated with glucose metabolism and lipogenesis in the livers of Jayanti rohu due to the inclusion of high carbohydrate levels in the diet. This study also encourages the exploration of early nutritional programming for enhancing glucose efficiency in carp species, for sustainable and cost-effective aquaculture production.

Reduction of JNK1 expression with antisense oligonucleotide improves adiposity in obese mice

2008 ◽  
Vol 295 (2) ◽  
pp. E436-E445 ◽  
Author(s):  
Xing Xian Yu ◽  
Susan F. Murray ◽  
Lynnetta Watts ◽  
Sheri L. Booten ◽  
Justin Tokorcheck ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Antisense Oligonucleotide ◽  
De Novo ◽  
Plasma Cholesterol ◽  
Liver Steatosis ◽  
Whole Body ◽  
Acid Oxidation ◽  
Mrna Levels ◽  
Obese Mice ◽  
Peripheral Tissues

To investigate the role of JNK1 in metabolism, male ob/ ob and diet-induced obese mice were treated with a JNK1-specific antisense oligonucleotide (ASO) or control ASO at 25 mg/kg or saline twice/wk for 6 and 7 wk, respectively. JNK1 ASO reduced JNK1 mRNA and activity by 65–95% in liver and fat tissues in both models. Compared with controls, treatment with JNK1 ASO did not change food intake but lowered body weight, fat pad weight, and whole body fat content. The treatment increased metabolic rate. In addition, the treatment markedly reduced plasma cholesterol levels and improved liver steatosis and insulin sensitivity. These positive observations were accompanied by the following changes: 1) increased mRNA levels of AR-β3 and UCP1 by >60% in BAT, 2) reduced mRNA levels of ACC1, ACC2, FAS, SCD1, DGAT1, DGAT2, and RBP4 by 30–60% in WAT, and 3) reduced mRNA levels of ACC1, FAS, G-6-Pase, and PKCε by 40–70% and increased levels of UCP2 and PPARα by more than twofold in liver. JNK1 ASO-treated mice demonstrated reduced levels of pIRS-1 Ser302 and pIRS-1 Ser307 and increased levels of pAkt Ser473 in liver and fat in response to insulin. JNK1 ASO-transfected mouse hepatocytes showed decreased rates of de novo sterol and fatty acid synthesis and an increased rate of fatty acid oxidation. These results indicate that inhibition of JNK1 expression in major peripheral tissues can improve adiposity via increasing fuel combustion and decreasing lipogenesis and could therefore provide clinical benefit for the treatment of obesity and related metabolic abnormalities.

Model for measuring absolute rates of hepatic de novo lipogenesis and reesterification of free fatty acids

1993 ◽  
Vol 265 (5) ◽  
pp. E814-E820 ◽  
Author(s):  
M. K. Hellerstein ◽  
R. A. Neese ◽  
J. M. Schwarz
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
De Novo ◽  
Human Subjects ◽  
Fat Oxidation ◽  
De Novo Lipogenesis ◽  
Whole Body ◽  
Distribution Analysis ◽  
Oxidation Rates ◽  
Mass Isotopomer Distribution Analysis

We have previously presented a precursor-product stable isotopic technique for measuring in vivo the fraction of very low-density lipoprotein-fatty acids (VLDL-FA) derived from de novo lipogenesis (fractional DNL). Here, we propose a technique for converting fractional DNL into absolute rates of DNL and describe its explicit underlying assumptions. The technique combines the fractional DNL method with a modification of the method of S. Klein, V. R. Young, G. L. A. Blackburn, B. R. Bistrain, and R. R. Wolfe (J. Clin. Invest. 78: 928-933, 1986), for estimating hepatic reesterification of free fatty acids (FFA). Infusions of [1,2,3,4-13C]palmitate and [1-13C]acetate are performed concurrently with indirect calorimetry in human subjects. Fractional DNL (based on mass isotopomer distribution analysis of VLDL-FA), the rate of appearance of plasma FFA (Ra of FFA), and net fat oxidation in the whole body are measured. Equations from the hepatic reesterification model, modified to include the contribution from DNL, allow calculation of absolute DNL (= fractional DNL x [Ra of FFA - net whole body fat oxidation], when respiratory quotient < 1.0). Sample results from human subjects with different dietary energy intakes are presented, with calculations of absolute DNL, absolute reesterification, and absolute fat oxidation rates. The assumptions of this technique (in particular, that all fat oxidized is derived at steady state from circulating FFA and that DNL and reesterification of FFA both occur exclusively in liver) are discussed.(ABSTRACT TRUNCATED AT 250 WORDS)

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