Targeting Glutamine Synthesis Inhibits Stem Cell Adipogenesis in Vitro
| Autor: | Michael E. Symonds, Amal Surrati, Ksenija Velickovic, Harold S. Sacks, Hilda Anaid Lugo Leija, Dong-Hyun Kim, Virginie Sottile |
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| Rok vydání: | 2020 |
| Předmět: |
Physiology
Glutamine lcsh:Physiology lcsh:Biochemistry chemistry.chemical_compound Mice Glutamate-Ammonia Ligase Adipocyte Glutamine synthetase Lipid droplet Gene expression Adipocytes Animals lcsh:QD415-436 Adipocytes Beige Cells Cultured Adipogenesis lcsh:QP1-981 Stem Cells Lipid metabolism Cell Differentiation Mesenchymal Stem Cells Lipid Droplets Cell biology Culture Media PPAR gamma chemistry Lipogenesis |
| Zdroj: | Cellular Physiology and Biochemistry, Vol 54, Iss 5, Pp 917-927 (2020) |
| ISSN: | 1421-9778 |
| Popis: | Background/aims Glutamine is the most abundant amino acid in the body and has a metabolic role as a precursor for protein, amino sugar and nucleotide synthesis. After glucose, glutamine is the main source of energy in cells and has recently been shown to be an important carbon source for de novo lipogenesis. Glutamine is synthesized by the enzyme glutamine synthetase, a mitochondrial enzyme that is active during adipocyte differentiation suggesting a regulatory role in this process. The aim of our study was therefore to investigate whether glutamine status impacts on the differentiation of adipocytes and lipid droplet accumulation. Methods Mouse mesenchymal stem cells (MSCs) were submitted to glutamine deprivation (i.e. glutamine-free adipogenic medium in conjunction with irreversible glutamine synthetase inhibitor, methionine sulfoximine - MSO) during differentiation and their response was compared with MSCs differentiated in glutamine-supplemented medium (5, 10 and 20 mM). Differentiated MSCs were assessed for lipid content using Oil Red O (ORO) staining and gene expression was analysed by qPCR. Intracellular glutamine levels were determined using a colorimetric assay, while extracellular glutamine was measured using liquid chromatography-mass spectrometry (LC-MS). Results Glutamine deprivation largely abolished adipogenic differentiation and lipid droplet formation. This was accompanied with a reduction in intracellular glutamine concentration, and downregulation of gene expression for classical adipogenic markers including PPARγ. Furthermore, glutamine restriction suppressed isocitrate dehydrogenase 1 (IDH1) gene expression, an enzyme which produces citrate for lipid synthesis. In contrast, glutamine supplementation promoted adipogenic differentiation in a dose-dependent manner. Conclusion These results suggest that the glutamine pathway may have a previously over-looked role in adipogenesis. The underlying mechanism involved the glutamine-IDH1 pathway and could represent a potential therapeutic strategy to treat excessive lipid accumulation and thus obesity. |
| Databáze: | OpenAIRE |
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