Triacylglycerol synthesis enhances macrophage inflammatory function
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE145523 | GEO | 2020/07/04
REPOSITORIES: GEO
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Project description:Methionine adenosyltransferase (MAT) enzymes generate SAMe (S-adenosylmethionine), the main biological methyl donor. There are two MAT encoding genes in mammals (Mat1a and Mat2a), which show different activities and cellular distribution. Mat1a encodes the enzyme mainly expressed in normal liver. Mat1a ablation in mice results in the spontaneous development of non-alcoholic steatohepatitis (NASH). We observed that SAMe depletion in Mat1a KO mice had three main effects on hepatic lipid metabolism: 1) impaired TG (triglyceride) export via VLDL; 2) impaired mitochondrial FA (fatty acid) oxidation (as evidenced by membrane depolarization, downregulation of Phb1 (prohibitin 1, a mitochondrial chaperone protein) and Mcj/Dnajc15 (endogenous mitochondrial repressor of respiratory chain), and accumulation of long-chain acylcarnitines); and 3) increased FA uptake. The convergence of these three factors induced TG accumulation in LD (lipid droplets). LD expansion confronts hepatocytes with a high demand of PC (phosphatidylcholine) molecules to cover the LD surface since other phospholipids, such as PE (phosphatidylethanolamine), cannot stabilize LD and prevent coalescence. In Mat1a KO this situation is aggravated, since SAMe-dependent PC synthesis via PE methylation is decreased, the PC/PE ratio reduced and mitochondrial FA oxidation impaired. To put a brake to this drain of PC molecules to LD, FA are rerouted in Mat1a KO mice liver to other catabolic (endoplasmic reticulum and peroxisome oxidation) and biosynthetic (ceramides synthesis) pathways, causing oxidative stress, inflammation and fibrosis. SAMe treatment for two months in 8-9 month old Mat1a KO mice ameliorated mitochondrial dysfunction (reduces membrane depolarization, improves Phb1 and Mcj expression, and increases SAMe transport to mitochondria) improving FA oxidation efficiency (FA and acylcarnitine levels decrease), which results in a drastic reduction in TG accumulation. SAMe treatment in Mat1a KO mice resulted in more PC available for proper membrane function, improving liver lipid homeostasis, histology (H&E, Sudan red, Sirius red) and liver injury (ALT, AST).
2017-02-02 | GSE77082 | GEO
Project description:Methionine adenosyltransferase (MAT) enzymes generate SAMe (S-adenosylmethionine), the main biological methyl donor. There are two MAT encoding genes in mammals (Mat1a and Mat2a), which show different activities and cellular distribution. Mat1a encodes the enzyme mainly expressed in normal liver. Mat1a ablation in mice results in the spontaneous development of non-alcoholic steatohepatitis (NASH). We observed that SAMe depletion in Mat1a KO mice had three main effects on hepatic lipid metabolism: 1) impaired TG (triglyceride) export via VLDL; 2) impaired mitochondrial FA (fatty acid) oxidation (as evidenced by membrane depolarization, downregulation of Phb1 (prohibitin 1, a mitochondrial chaperone protein) and Mcj/Dnajc15 (endogenous mitochondrial repressor of respiratory chain), and accumulation of long-chain acylcarnitines); and 3) increased FA uptake. The convergence of these three factors induced TG accumulation in LD (lipid droplets). LD expansion confronts hepatocytes with a high demand of PC (phosphatidylcholine) molecules to cover the LD surface since other phospholipids, such as PE (phosphatidylethanolamine), cannot stabilize LD and prevent coalescence. In Mat1a KO this situation is aggravated, since SAMe-dependent PC synthesis via PE methylation is decreased, the PC/PE ratio reduced and mitochondrial FA oxidation impaired. To put a brake to this drain of PC molecules to LD, FA are rerouted in Mat1a KO mice liver to other catabolic (endoplasmic reticulum and peroxisome oxidation) and biosynthetic (ceramides synthesis) pathways, causing oxidative stress, inflammation and fibrosis. SAMe treatment for two months in 8-9 month old Mat1a KO mice ameliorated mitochondrial dysfunction (reduces membrane depolarization, improves Phb1 and Mcj expression, and increases SAMe transport to mitochondria) improving FA oxidation efficiency (FA and acylcarnitine levels decrease), which results in a drastic reduction in TG accumulation. SAMe treatment in Mat1a KO mice resulted in more PC available for proper membrane function, improving liver lipid homeostasis, histology (H&E, Sudan red, Sirius red) and liver injury (ALT, AST).
2017-02-02 | GSE77079 | GEO
Project description:Liver steatosis can be induced by fasting or high-fat diet. We investigated by lipidomic analysis whether such metabolic states are reflected in the lipidome of hepatocyte lipid droplets (LDs) from mice fed normal chow diet (FED), fasted (FAS), or fed a high-fat diet (HFD). LC-MS/MS at levels of lipid species profiles and of lipid molecular species uncovered a FAS phenotype of LD enriched in triacylglycerol (TG) molecular species with very long-chain (VLC)-PUFA residues and an HFD phenotype with less unsaturated TG species in addition to characteristic lipid marker species. Nutritional stress did not result in dramatic structural alterations in diacylglycerol (DG) and phospholipid (PL) classes. Moreover, molecular species of bulk TG and of DG indicated concomitant de novo TG synthesis and lipase-catalyzed degradation to be active in LDs. DG species with VLC-PUFA residues would be preferred precursors for phosphatidylcholine (PC) species, the others for TG molecular species. In addition, molecular species of PL classes fitted the hepatocyte Kennedy and phosphatidylethanolamine methyltransferase pathways. We demonstrate that lipidomic analysis of LDs enables phenotyping of nutritional stress. TG species are best suited for such phenotyping, whereas structural analysis of TG, DG, and PL molecular species provides metabolic insights.
2014-08-19 | MTBLS26 | MetaboLights
Project description:Interventions: TG group:GDFT combined with traditional ventilation;PG group:GDFT and LPS
Primary outcome(s): Respiratory dynamics index
Study Design: Parallel
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Project description:we explored the novel role of Lipopolysaccharide-binding protein (LBP) as an anti-oxidant, which can capture unsaturated triglyceride (TG) into LDs to avoid lipid peroxidation. Oxidative stress upregulates LBP level and promotes LDs growth via the LBP/TG phase transition. Upon N-Acetyl-L-cysteine (NAC) elimination of ROS, LBP is exported from LD along with PRDX4, resulting in an increase in phospholipid synthesis. Chronic stress causes LBP upregulation and leads to obesity, which can be rescued by NAC treatment in vivo. These results support that LBP maintains homeostasis by coupling lipid metabolism and redox signal, which provides insights into redox medicine that mitigate stress-induced metabolic dysfunction.
2024-04-10 | PXD040940 | Pride
Project description:AbstractBackground: A decreased intramuscular carnitine status with aging may contribute to frailty and fatigue, but studies are often confounded by sex-heterogeneity and lack of control groups. We hypothesize that muscle carnitine deficiency is associated with (pre-)frailty, diminished physical performance and altered mitochondrial function, possibly in a sex-dependent manner. This was tested in well-matched age groups, allowing gender-specific analyses. Methods: A cross-sectional study was performed in well-matched fit (n = 15) and (pre-)frail (n = 13) old males as well as in fit (n = 15) and (pre-)frail (n = 11) old females, using young males (n = 13) and females (n = 13) as healthy controls. In the elderly, frailty was assessed according to the Fried criteria and physical performance was determined by 400-m walk test, short physical performance battery and handgrip strength. Acylcarnitine status was assessed in muscle biopsies and blood plasma using liquid chromatography-tandem mass spectrometry. Muscle mitochondrial gene expression was analyzed. Results: Intramuscular total carnitine levels and short chain acylcarnitine levels were lower in (pre-)frail old females compared to fit old females and young females, whereas no differences were observed in males. Intramuscular short chain acylcarnitine levels were associated with low physical performance in females, even after correction for muscle mass (%), whereas in males no such association was found. The decline in short chain acylcarnitine levels in (pre-)frail old females was associated with low expression of genes involved in mitochondrial energy production and mitochondrial functionality. Conclusions: In (pre-)frail old females, intramuscular total carnitine levels and short chain acylcarnitine levels are decreased and this decrease is accompanied by reduced physical performance and low expression of a wide range of genes involved in mitochondrial function.
2023-02-04 | GSE144304 | GEO
Project description:Lipid droplets (LDs) are multifunctional organelles consisting of a central compartment of non-polar lipids shielded from the cytoplasm by a phospholipid monolayer. The excessive accumulation of lipid droplets in cells is closely related to the development and progression of many diseases in humans and animals, such as liver-related and cardiovascular diseases. Thus, regulating the LDs size and abundance is necessary to maintain metabolic homeostasis. In this study, we found that LPS stimulation reduced the LDs content in the mouse liver. We tried to explain the possible molecular mechanisms at the broad protein and mRNA levels, finding that inhibition of the peroxisome proliferator-activated receptors (PPAR) signalling pathway by LPS may be a critical factor in reducing LDs content.
2023-02-02 | GSE224012 | GEO
Project description:This data set was downloaded from MetaboLights (http://www.ebi.ac.uk/metabolights/) accession number MTBLS26 Abstract:Liver steatosis can be induced by fasting or high-fat diet. We investigated by lipidomic analysis whether such metabolic states are reflected in the lipidome of hepatocyte lipid droplets (LDs) from mice fed normal chow diet (FED), fasted (FAS), or fed a high-fat diet (HFD). LC-MS/MS at levels of lipid species profiles and of lipid molecular species uncovered a FAS phenotype of LD enriched in triacylglycerol (TG) molecular species with very long-chain (VLC)-PUFA residues and an HFD phenotype with less unsaturated TG species in addition to characteristic lipid marker species. Nutritional stress did not result in dramatic structural alterations in diacylglycerol (DG) and phospholipid (PL) classes. Moreover, molecular species of bulk TG and of DG indicated concomitant de novo TG synthesis and lipase-catalyzed degradation to be active in LDs. DG species with VLC-PUFA residues would be preferred precursors for phosphatidylcholine (PC) species, the others for TG molecular species. In addition, molecular species of PL classes fitted the hepatocyte Kennedy and phosphatidylethanolamine methyltransferase pathways. We demonstrate that lipidomic analysis of LDs enables phenotyping of nutritional stress. TG species are best suited for such phenotyping, whereas structural analysis of TG, DG, and PL molecular species provides metabolic insights.
2017-05-30 | MSV000081123 | GNPS
Project description:Triacylglycerol synthesis enhances macrophage inflammatory function
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Project description:The primary aim of the study is to investigate the temporal changes in plasma lipidome before and after reperfusion in patients with ST-segment elevation myocardial infarction (STEMI) and their association with myocardial injury. We found that 56% of the identified lipid species were significantly altered (corrected p< 0.05) in the first 24 h following reperfusion in patients with STEMI. Three lipid species, namely, acylcarnitine 18:2, TG 51:0, and LPC 17:1 were associated with a change in troponin concentration (delta troponin) and in-hospital cardiovascular events. Of these, acylcarnitine 18:2, and LPC 17:1 and their respective whole class levels, were significantly higher (p < 0.05) in the STEMI population than the age/sex-matched control subjects. Overall, our analyses showed a large shift in plasma lipidome in patients that undergo myocardial reperfusion. The differences found for acylcarnitines and LPC species and their association with both cardiac markers and cardiac outcomes need further validation.
2022-02-07 | MTBLS3839 | MetaboLights