Biology subjects

Artigues, A.

Publications and source records attributed to Artigues, A..

3 recordsLinked to original sources

bioRxiv2024

Multi-Omics after O-GlcNAc Alteration Identifies Cellular Processes Working Synergistically to Promote Aneuploidy

Pharmacologic or genetic manipulation of O-GlcNAcylation, an intracellular, single sugar post-translational modification, are difficult to interpret due to the pleotropic nature of O-GlcNAc and the vast signaling pathways it regulates. To address this issue, we employed either OGT (O-GlcNAc transferase), OGA (O-GlcNAcase) liver knockouts, or pharmacological inhibition of OGA coupled with multi-Omics analysis and bioinformatics. We identified numerous genes, proteins, phospho-proteins, or metabolites that were either inversely or equivalently changed between conditions. Moreover, we identified pathways in OGT knockout samples associated with increased aneuploidy. To test and validate these pathways, we induced liver growth in OGT knockouts by partial hepatectomy. OGT knockout livers showed a robust aneuploidy phenotype with disruptions in mitosis, nutrient sensing, protein metabolism/amino acid metabolism, stress response, and HIPPO signaling demonstrating how OGT is essential in controlling aneuploidy pathways. Moreover, these data show how a multi-Omics platform can discern how OGT can synergistically fine-tune multiple cellular pathways.

cell biology↗

bioRxiv2019

Mutational mimics of allosteric effectors: a genome editing design to validate allosteric drug targets

Development of drugs that allosterically regulate enzyme functions to treat disease is a costly venture. Screening mutations that mimic allosteric effectors in vitro will identify therapeutic regulatory targets enhancing the likelihood of developing a disease treatment at a reasonable cost. We demonstrate the potential of this approach utilizing human liver pyruvate kinase (hLPYK) as a model. Inhibition of hLPYK was the first desired outcome of our screen. We identified individual point mutations that: 1) mimicked allosteric inhibition by alanine, 2) mimicked inhibition by protein phosphorylation, and 3) prevented binding of fructose-1,6-bisphosphate (Fru-1,6-BP). Our second desired screening outcome was activation of hLPYK. We identified individual point mutations that: 1) prevented hLPYK from binding alanine, the allosteric inhibitor, 2) prevented inhibitory protein phosphorylation, or 3) mimicked allosteric activation by Fru-1,6-BP. Combining the three activating point mutations produced a constitutively activated enzyme that was unresponsive to regulators. Expression of a mutant hLPYK transgene containing these three mutations in a mouse model was not lethal. Thus, mutational mimics of allosteric effectors will be useful to confirm whether allosteric activation of hLPYK will control glycolytic flux in the diabetic liver to reduce hepatic glucose production and, in turn, reduce or prevent hyperglycemia.

biochemistry↗

bioRxiv2018

Elevated O-GlcNAcylation Enhances Pro-Inflammatory Th17 Function by Altering the Lipid Microenvironment

Chronic, low-grade inflammation increases the risk of atherosclerosis, cancer, and autoimmunity in diseases like obesity and diabetes. Here, we show that increased levels of the nutrient-responsive, post-translational protein modification, O-GlcNAc (O-linked {beta}-N-acetylglucosamine) are present in naive CD4+ T cells from a diet-induced obesity murine model, and elevation in O-GlcNAc leads to increased pro-inflammatory IL-17A production. Importantly, CD4+ T helper 17 (Th17) cells, which secrete IL-17A, are increased in obesity and contribute to the inflammatory milieu. We found increased binding of the Th17 master transcription factor, ROR{gamma}t, at the IL-17 locus and significant alterations in the lipid microenvironment, leading to increased ligands capable of increasing ROR{gamma}t transcriptional activity. Importantly, the rate-limiting enzyme of fatty acid biosynthesis, acetyl CoA carboxylase 1 (ACC1), is necessary for production of these ROR{gamma}t activating ligands and is O-GlcNAcylated. Thus, we have identified O-GlcNAc as a critical link between excess nutrients and pathological inflammation.

immunology↗