Quantitative analysis of acetoacetate metabolism in AS-30D hepatoma cells with 13C and 14C isotopic techniques

1997 ◽  
Vol 272 (6) ◽  
pp. E945-E951 ◽  
Author(s):  
A. L. Holleran ◽  
G. Fiskum ◽  
J. K. Kelleher
Keyword(s):  
De Novo ◽  
Lipid Synthesis ◽  
Tca Cycle ◽  
Hepatoma Cells ◽  
Dichloroacetic Acid ◽  
De Novo Lipogenesis ◽  
Ratio Method ◽  
Acetyl Coa ◽  
Isotopic Methods ◽  
Host Metabolism

Experimental hepatoma cells utilize acetoacetate as an oxidative energy source and as a precursor for lipid synthesis. The significance of ketone body metabolism in tumors lies in the study of tumor-host metabolism and the ketoneMic condition that is often present in cancer patients. The quantitative importance of acetoacetate and glucose was investigated in AS-30D cells with use of 13C and 14C isotopic methods. In addition, the effects of acetoacetate were compared with those of dichloroacetic acid (DCA), an activator of pyruvate dehydrogenase (PDH). The 14CO2 ratio method evaluated the entry of pyruvate into the tricarboxylic acid (TCA) cycle and revealed that acetoacetate diverted pyruvate from PDH to pyruvate carboxylation. In contrast, DCA increased the oxidation of glucose largely through PDH, indicating that PDH is not maximally active in the absence of DCA. Isotopomer spectral analysis of lipid synthesis demonstrated that, in the absence of acetoacetate, glucose supplied 65% of the acetyl-CoA used for de novo lipogenesis. When 5 mM acetoacetate was included in the incubation, glucose was displaced as a lipogenic precursor and acetoacetate supplied 85% of the acetyl-CoA for lipogenesis vs. only 2% for glucose. Thus AS-30D cells have a large capacity for acetoacetate utilization for de novo lipogenesis.

scholarly journals Physical Activity Reduces Anxiety And Regulates Brain Fatty Acid Synthesis

2020 ◽  
Author(s):  
Arkadiusz Damian Liśkiewicz ◽  
Marta Przybyła ◽  
Anna Wojakowska ◽  
Łukasz Marczak ◽  
Katarzyna Bogus ◽  
...  
Keyword(s):  
Physical Activity ◽  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
De Novo ◽  
Lipid Synthesis ◽  
Tca Cycle ◽  
Acid Synthesis ◽  
De Novo Lipogenesis ◽  
Brain Functions ◽  
The Brain

Abstract Physical activity impacts brain functions, but the direct mechanisms of this effect are not fully recognized or understood. Among multidimensional changes induced by physical activity, brain fatty acids (FA) appear to play an important role; however, the knowledge in this area is particularly scarce. Here we performed global metabolomics profiling of the hippocampus and the frontal cortex (FC) in a model of voluntary running in mice. Examined brain structures responded differentially to physical activity. Specifically, the markers of the tricarboxylic acid (TCA) cycle were downregulated in the FC, whereas glycolysis was enhanced in the hippocampus. Physical activity stimulated production of myristic, palmitic and stearic FA; i.e., the primary end products of de novo lipogenesis in the brain, which was accompanied by increased expression of hippocampal fatty acid synthase (FAS), suggesting stimulation of lipid synthesis. The changes in the brain fatty acid profile were associated with reduced anxiety level in the running mice. Overall, the study examines exercise-related metabolic changes in the brain and links them to behavioral outcomes.

scholarly journals Physical Activity Reduces Anxiety And Regulates Brain Fatty Acid Synthesis

2020 ◽  
Author(s):  
Arkadiusz Damian Liśkiewicz ◽  
Marta Przybyła ◽  
Anna Wojakowska ◽  
Łukasz Marczak ◽  
Katarzyna Bogus ◽  
...  
Keyword(s):  
Physical Activity ◽  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
De Novo ◽  
Lipid Synthesis ◽  
Tca Cycle ◽  
Acid Synthesis ◽  
De Novo Lipogenesis ◽  
Brain Functions ◽  
The Brain

Abstract Physical activity impacts brain functions, but the direct mechanisms of this effect are not fully recognized or understood. Among multidimensional changes induced by physical activity, brain fatty acids (FA) appear to play an important role; however, the knowledge in this area is particularly scarce. Here we performed global metabolomics profiling of the hippocampus and the frontal cortex (FC) in a model of voluntary running in mice. Examined brain structures responded differentially to physical activity. Specifically, the markers of the tricarboxylic acid (TCA) cycle were downregulated in the FC, whereas glycolysis was enhanced in the hippocampus. Physical activity stimulated production of myristic, palmitic and stearic FA; i.e., the primary end products of de novo lipogenesis in the brain, which was accompanied by increased expression of hippocampal fatty acid synthase (FAS), suggesting stimulation of lipid synthesis. The changes in the brain fatty acid profile were associated with reduced anxiety level in the running mice. Overall, the study examines exercise-related metabolic changes in the brain and links them to behavioral outcomes.

scholarly journals Toxoplasma gondii acetyl-CoA synthetase is involved in fatty acid elongation (of long fatty acid chains) during tachyzoite life stages

2018 ◽  
Vol 59 (6) ◽  
pp. 994-1004 ◽  
Author(s):  
David Dubois ◽  
Stella Fernandes ◽  
Souad Amiar ◽  
Sheena Dass ◽  
Nicholas J. Katris ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Toxoplasma Gondii ◽  
Isotope Labeling ◽  
De Novo ◽  
Lipid Synthesis ◽  
Minor Effect ◽  
Parasite Line ◽  
Acetyl Coa ◽  
Apicomplexan Parasites ◽  
A Minor

Apicomplexan parasites are pathogens responsible for major human diseases such as toxoplasmosis caused by Toxoplasma gondii and malaria caused by Plasmodium spp. Throughout their intracellular division cycle, the parasites require vast and specific amounts of lipids to divide and survive. This demand for lipids relies on a fine balance between de novo synthesized lipids and scavenged lipids from the host. Acetyl-CoA is a major and central precursor for many metabolic pathways, especially for lipid biosynthesis. T. gondii possesses a single cytosolic acetyl-CoA synthetase (TgACS). Its role in the parasite lipid synthesis is unclear. Here, we generated an inducible TgACS KO parasite line and confirmed the cytosolic localization of the protein. We conducted 13C-stable isotope labeling combined with mass spectrometry-based lipidomic analyses to unravel its putative role in the parasite lipid synthesis pathway. We show that its disruption has a minor effect on the global FA composition due to the metabolic changes induced to compensate for its loss. However, we could demonstrate that TgACS is involved in providing acetyl-CoA for the essential fatty elongation pathway to generate FAs used for membrane biogenesis. This work provides novel metabolic insight to decipher the complex lipid synthesis in T. gondii.

scholarly journals Hepatic Transcriptomics Reveals that Lipogenesis Is a Key Signaling Pathway in Isocitrate Dehydrogenase 2 Deficient Mice

Genes ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 728
Author(s):  
Jeong Hoon Pan ◽  
Jingsi Tang ◽  
Mersady C. Redding ◽  
Kaleigh E. Beane ◽  
Cara L. Conner ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Isocitrate Dehydrogenase ◽  
De Novo ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Tca Cycle ◽  
De Novo Lipogenesis ◽  
Oxidative Decarboxylation ◽  
Qpcr Analysis ◽  
Isocitrate Dehydrogenase 2 ◽  
Mice Liver

Mitochondrial nicotinamide adenine dinucleotide phosphate (NADP+)-dependent isocitrate dehydrogenase (IDH2) plays a key role in the intermediary metabolism and energy production via catalysing oxidative decarboxylation of isocitrate to α-ketoglutarate in the tricarboxylic acid (TCA) cycle. Despite studies reporting potential interlinks between IDH2 and various diseases, there is lack of effort to comprehensively characterize signature(s) of IDH2 knockout (IDH2 KO) mice. A total of 6583 transcripts were identified from both wild-type (WT) and IDH2 KO mice liver tissues. Afterwards, 167 differentially expressed genes in the IDH2 KO group were short-listed compared to the WT group based on our criteria. The online bioinformatic analyses indicated that lipid metabolism is the most significantly influenced metabolic process in IDH2 KO mice. Moreover, the TR/RXR activation pathway was predicted as the top canonical pathway significantly affected by IDH2 KO. The key transcripts found in the bioinformatic analyses were validated by qPCR analysis, corresponding to the transcriptomics results. Further, an additional qPCR analysis confirmed that IDH2 KO caused a decrease in hepatic de novo lipogenesis via the activation of the fatty acid β-oxidation process. Our unbiased transcriptomics approach and validation experiments suggested that IDH2 might play a key role in homeostasis of lipid metabolism.

scholarly journals The Spot 14 Protein Is Required for de Novo Lipid Synthesis in the Lactating Mammary Gland

Endocrinology ◽  
2005 ◽  
Vol 146 (8) ◽  
pp. 3343-3350 ◽  
Author(s):  
Qihong Zhu ◽  
Grant W. Anderson ◽  
Gregory T. Mucha ◽  
Elizabeth J. Parks ◽  
Jennifer K. Metkowski ◽  
...  
Keyword(s):  
Mammary Gland ◽  
De Novo ◽  
Lipid Synthesis ◽  
De Novo Lipogenesis ◽  
Direct Result ◽  
Maximum Efficiency ◽  
Null Mouse ◽  
Wild Type ◽  
Spot 14 ◽  
Lactating Mammary Gland

Abstract We generated a Spot 14 null mouse to assess the role of Spot 14 in de novo lipid synthesis and report the Spot 14 null mouse exhibits a phenotype in the lactating mammary gland. Spot 14 null pups nursed by Spot 14 null dams gain significantly less weight than wild-type pups nursed by wild-type dams. In contrast, Spot 14 null pups nursed by heterozygous dams show similar weight gain to wild-type littermates. We found the triglyceride content in Spot 14 null milk is significantly reduced. We demonstrate this reduction is the direct result of decreased de novo lipid synthesis in lactating mammary glands, corroborated by a marked reduction of medium-chain fatty acids in the triglyceride pool. Importantly, the reduced lipogenic rate is not associated with significant changes in the activities or mRNA of key lipogenic enzymes. Finally, we report the expression of a Spot 14-related gene in liver and adipose tissue, which is absent in the lactating mammary gland. We suggest that expression of both the Spot 14 and Spot 14-related proteins is required for maximum efficiency of de novo lipid synthesis in vivo and that these proteins impart a novel mechanism regulating de novo lipogenesis.

Androgen stimulates glycolysis for de novo lipid synthesis by increasing the activities of hexokinase 2 and 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 2 in prostate cancer cells

2010 ◽  
Vol 433 (1) ◽  
pp. 225-233 ◽  
Author(s):  
Jong-Seok Moon ◽  
Won-Ji Jin ◽  
Jin-Hye Kwak ◽  
Hyo-Jeong Kim ◽  
Mi-Jin Yun ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cancer Cells ◽  
Transcriptional Activation ◽  
De Novo ◽  
Lipid Synthesis ◽  
Signalling Pathway ◽  
De Novo Lipogenesis ◽  
Lncap Cells ◽  
Prostate Cancer Cells ◽  
Hexokinase 2

Up-regulation of lipogenesis by androgen is one of the most characteristic metabolic features of LNCaP prostate cancer cells. The present study revealed that androgen increases glucose utilization for de novo lipogenesis in LNCaP cells through the activation of HK2 (hexokinase 2) and activation of the cardiac isoform of PFKFB2 (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase). Activation of PKA (cAMP-dependent protein kinase) by androgen increased phosphorylation of CREB [CRE (cAMP-response element)-binding protein], which in turn bound to CRE on the promoter of the HK2 gene resulting in transcriptional activation of the HK2 gene. Up-regulation of PFKFB2 expression was mediated by the direct binding of ligand-activated androgen receptor to the PFKFB2 promoter. The activated PI3K (phosphoinositide 3-kinase)/Akt signalling pathway in LNCaP cells contributes to the phosphorylation of PFKFB2 at Ser466 and Ser483, resulting in the constitutive activation of PFK-2 (6-phosphofructo-2-kinase) activity. Glucose uptake and lipogenesis were severely blocked by knocking-down of PFKFB2 using siRNA (small interfering RNA) or by inhibition of PFK-2 activity with LY294002 treatment. Taken together, our results suggest that the induction of de novo lipid synthesis by androgen requires the transcriptional up-regulation of HK2 and PFKFB2, and phosphorylation of PFKFB2 generated by the PI3K/Akt signalling pathway to supply the source for lipogenesis from glucose in prostate cancer cells.

scholarly journals The DAXX-SREBP axis promotes oncogenic lipogenesis and tumorigenesis

2021 ◽  
Author(s):  
Iqbal Mahmud ◽  
Guimei Tian ◽  
Jia Wang ◽  
Jessica Lewis ◽  
Aaron Waddell ◽  
...  
Keyword(s):  
Gene Expression ◽  
Tumor Growth ◽  
De Novo ◽  
Lipid Synthesis ◽  
De Novo Lipogenesis ◽  
Recent Analysis ◽  
Gene Promoters ◽  
Lipogenic Gene ◽  
Lipogenic Gene Expression ◽  
Cancer Types

ABSTRACTDe novo lipogenesis produces lipids for membrane biosynthesis and cell signaling. Elevated lipogenesis is a major metabolic feature in cancer cells. In breast and other cancer types, genes involved in lipogenesis are highly upregulated, but the mechanisms that control their expression remain poorly understood. DAXX modulates gene expression through binding to diverse transcription factors although the functional impact of these diverse interactions remains to be defined. Our recent analysis indicates that DAXX is overexpressed in diverse cancer types. However, mechanisms underlying DAXX’s oncogenic function remains elusive. Using global integrated transcriptomic and lipidomic analyses, we show that DAXX plays a key role in lipid metabolism. DAXX depletion attenuates, while its overexpression enhances, lipogenic gene expression, lipid synthesis and tumor growth. Mechanistically, DAXX interacts with SREBP1 and SREBP2 and activates SREBP-mediated transcription. DAXX associates with lipogenic gene promoters through SREBPs. Underscoring the critical roles for the DAXX-SREBP interaction for lipogenesis, SREBP2 knockdown attenuates tumor growth in cells with DAXX overexpression, and a DAXX mutant unable to bind SREBPs are incapable of promoting lipogenesis and tumor growth. Our results identify the DAXX-SREBP axis as an important pathway for tumorigenesis.

scholarly journals Transfer of glucose hydrogens via acetyl-CoA, malonyl-CoA, and NADPH to fatty acids during de novo lipogenesis

2019 ◽  
Vol 60 (12) ◽  
pp. 2050-2056 ◽  
Author(s):  
Getachew Debas Belew ◽  
Joao Silva ◽  
Joao Rito ◽  
Ludgero Tavares ◽  
Ivan Viegas ◽  
...  
Keyword(s):  
Fatty Acids ◽  
De Novo ◽  
De Novo Lipogenesis ◽  
Acetyl Coa ◽  
Malonyl Coa
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