Showing papers by "Daniel J. Fazakerley published in 2020"
TL;DR: It is noted that knocking down lactate dehydrogenase specifically in the fat body of Drosophila flies lowered circulating lactate and improved whole-body glucose disposal and emphasized that lactate production is an additional metabolic role of adipose tissue beyond lipid storage and release.
36 citations
TL;DR: Testing whether glucose is necessary for insulin-stimulated anabolism in adipocytes revealed that glucose was required for insulin to stimulate pathways providing carbon substrate, NADPH, and glycerol 3-phosphate for lipid synthesis and storage, and lipid abundance was sensitive to glucose availability.
29 citations
TL;DR: An efficient 13C-tracer dynamic metabolic flux analysis (13C-DMFA) framework for modeling central carbon fluxes that vary over time is developed and B-splines are used to generalize the flux parameterization system and to improve the stability of the optimization algorithm.
23 citations
TL;DR: In this paper, the authors used rat adipocytes and cultured 3T3-L1 adipocytes to show that insulin increased respiration, but notably this occurred independently of glucose supply, while glucose was required for insulin to increase mitochondrial oxidants.
16 citations
TL;DR: Using biochemical and mass spectrometry analyses, TRARG1 is dephosphorylated in response to insulin in a PI3K/Akt-dependent manner and is a novel substrate for GSK3, and insights are provided into how TRarG1 regulates GLUT4 trafficking in adipocytes.
Abstract: Trafficking regulator of GLUT4-1, TRARG1, positively regulates insulin-stimulated GLUT4 trafficking and insulin sensitivity. However, the mechanism(s) by which this occurs remain(s) unclear. Using biochemical and mass spectrometry analyses we found that TRARG1 is dephosphorylated in response to insulin in a PI3K/Akt-dependent manner and is a novel substrate for GSK3. Priming phosphorylation of mouse TRARG1 at serine 84 allows for GSK3-directed phosphorylation at serines 72, 76 and 80. A similar pattern of phosphorylation was observed in human TRARG1, suggesting that our findings are translatable to human TRARG1. Pharmacological inhibition of GSK3 increased cell surface GLUT4 in cells stimulated with a submaximal insulin dose, and this was impaired following Trarg1 knockdown, suggesting that TRARG1 acts as a GSK3-mediated regulator in GLUT4 trafficking. TRARG1 dephosphorylation in response to insulin or GSK3 inhibition regulated its protein-protein interactions, decreasing the interaction between TRARG1 and BCL9L, JAGN1, PYGO2 and HSD17B12. Knock-down of Bcl9l promoted GLUT4 translocation to the plasma membrane. These data place TRARG1 within the insulin signaling network and provide insights into how TRARG1 regulates GLUT4 trafficking in adipocytes.
9 citations
TL;DR: A phenotypic chemical library screening approach was used to identify molecules that disrupted nutrient metabolism and were toxic to cancer cells and discovered a 1,4-Naphthoquinone (referred to as BH10) that is toxic to a broad range of cancer cell types.
Abstract: A hallmark of cancer cells is their ability to reprogram nutrient metabolism. Thus, disruption to this phenotype is a potential avenue for anti-cancer therapy. Herein we used a phenotypic chemical library screening approach to identify molecules that disrupted nutrient metabolism (by increasing cellular oxygen consumption rate) and were toxic to cancer cells. From this screen we discovered a 1,4-Naphthoquinone (referred to as BH10) that is toxic to a broad range of cancer cell types. BH10 has improved cancer-selective toxicity compared to doxorubicin, 17-AAG, vitamin K3, and other known anti-cancer quinones. BH10 increases glucose oxidation via both mitochondrial and pentose phosphate pathways, decreases glycolysis, lowers GSH:GSSG and NAPDH/NAPD+ ratios exclusively in cancer cells, and induces necrosis. BH10 targets mitochondrial redox defence as evidenced by increased mitochondrial peroxiredoxin 3 oxidation and decreased mitochondrial aconitase activity, without changes in markers of cytosolic or nuclear damage. Over-expression of mitochondria-targeted catalase protects cells from BH10-mediated toxicity, while the thioredoxin reductase inhibitor auranofin synergistically enhances BH10-induced peroxiredoxin 3 oxidation and cytotoxicity. Overall, BH10 represents a 1,4-Naphthoquinone with an improved cancer-selective cytotoxicity profile via its mitochondrial specificity.
9 citations