Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

BxPC-3 cells: growth in different nutrients

ABSTRACT: The MondoA transcription factor forms a heterocomplex with its obligate partner Mlx to regulate ~75% of glucose-dependent transcription. By mediating glucose-induced activation of thioredoxin-interacting protein (TXNIP), MondoA directly represses glucose uptake. Given the predominant role of MondoA in controlling glucose-dependent transcription and glucose uptake, we asked whether glutamine regulates MondoA activity. Expression profiles from glucose and glutamine starved BxPC-3 cells (-G-Q) were compared with those from cells grown in glucose only (+G-Q), glutamine only (-G+Q) or glucose plus glutamine (+G+Q). As expected, TXNIP expression was highly induced by glucose. However, the addition of glutamine repressed the glucose-dependent induction of TXNIP. We show that glutamine inhibits MondoA-dependent transcriptional activation of TXNIP by triggering the recruitment of a histone deacetylase-dependent corepressor to the amino terminus of MondoA. Consistent with the repression of TXNIP, glucose uptake is elevated in cells grown in the presence of glucose and glutamine. Finally, alpha-ketoglutarate, a tricarboxylic acid cycle intermediate, also blocks MondoA-dependent activation of TXNIP and stimulates glucose uptake. Together, these results suggest that glutamine-dependent mitochondrial anapleurosis stimulates glucose uptake by restricting TXNIP expression via MondoA:Mlx complexes. Four growth conditons; four biological replicates

ORGANISM(S): Homo sapiens

SUBMITTER: Don Ayer

PROVIDER: E-GEOD-17632 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Glutamine-dependent anapleurosis dictates glucose uptake and cell growth by regulating MondoA transcriptional activity.

Kaadige Mohan R MR Looper Ryan E RE Kamalanaadhan Sadhaasivam S Ayer Donald E DE

Proceedings of the National Academy of Sciences of the United States of America 20090817 35

Glucose and glutamine are abundant nutrients required for cell growth, yet how cells sense and adapt to changes in their levels is not well understood. The MondoA transcription factor forms a heterocomplex with its obligate partner Mlx to regulate approximately 75% of glucose-dependent transcription. By mediating glucose-induced activation of thioredoxin-interacting protein (TXNIP), MondoA:Mlx complexes directly repress glucose uptake. We show here that glutamine inhibits transcriptional activat ...[more]

PMID: 19706488

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Project description:BACKGROUND: Protein synthesis is regulated by the availability of amino acids, the engagement of growth factor signaling pathways and ATP levels sufficient to support translation. Crosstalk between these inputs is extensive, yet other regulatory mechanisms remain to be characterized. For example, the translation initiation inhibitor Rocaglamide A (RocA) induces Thioredoxin Interacting Protein (TXNIP). TXNIP is a negative regulator of glucose uptake, thus its induction by RocA links translation to the availability of glucose. MondoA is the principal regulator of glucose-induced transcription and its activity is triggered by the glycolytic intermediate, glucose 6-phosphate (G6P). MondoA responds to G6P generated by cytoplasmic glucose and mitochondrial ATP (mtATP), suggesting a critical role in the cellular response to these energy sources. TXNIP expression is entirely dependent on MondoA, therefore, we investigated how protein synthesis inhibitors impact its transcriptional activity. METHODS: We investigated how translation regulates MondoA activity using cell line models and loss-of-function approaches. We examined how protein synthesis inhibitors effect gene expression and metabolism using RNA-sequencing and metabolomics, respectively. The biological impact of RocA was evaluated using both cell line models and Patient-Derived Xenograft Organoid models. RESULTS: We discovered that multiple protein synthesis inhibitors, including RocA, increase TXNIP expression in a manner that depends on MondoA, a functional electron transport chain and mtATP synthesis. Furthermore, RocA increases mtATP and G6P levels and TXNIP induction depends on interactions between the Voltage-Dependent Anion Channel (VDAC) and hexokinase, which generates G6P. RocA treatment impacts the regulation of ~1200 genes and ~250 of those genes are MondoA-dependent. RocA treatment is cytotoxic to Triple Negative Breast Cancer cell lines and shows preferential cytotoxicity against ER- patient-derived breast cancer models. Finally, RocA-driven cytotoxicity is partially-dependent on MondoA or TXNIP. CONCLUSION: Our data suggest that protein synthesis inhibitors rewire metabolism, resulting in an increase in mtATP and G6P, the latter driving MondoA-dependent transcriptional activity. Further, MondoA is a critical component of the cellular transcriptional response to RocA. Our functional assays suggest that RocA or similar translation inhibitors may show efficacy against ER- tumors and that the levels of MondoA and TXNIP should be considered when exploring these potential treatment options.

Project description:Although a large set of data is available concerning organogenesis in animal models, information remains scarce on human organogenesis. In this work, we performed temporal mapping of human fetal pancreatic organogenesis using cell surface markers. We demonstrate that in the human fetal pancreas at 7 weeks of development, the glycoprotein 2 (GP2) marks a multipotent cell population that will differentiate either into the acinar, ductal and endocrine lineages. Development towards the acinar lineage is paralleled by a substantial increase in GP2 expression. Conversely, a subset of the multipotent GP2+ population undergoes endocrine differentiation by down-regulating GP2 and CD142 and turning on NEUROG3, an early marker of endocrine differentiation. Endocrine maturation will progress by up-regulating SUSD2 and lowering ECAD levels. Finally, we show that in vitro differentiation of pancreatic endocrine cells derived from human pluripotent stem cells mimics key in vivo events. Our work constitutes a powerful approach to more precisely define intermediate cell population during conversion of multipotent progenitors into the 3 main human pancreatic cell types (acinar, ductal and endocrine) in vivo. As such, the data pave the way to extend our understanding of the origin of mature human pancreatic cell types and how such lineage decisions are regulated. While the mechanisms by which glucose regulates insulin secretion from pancreatic beta cells are now well described, the way glucose modulates gene expression in such cells needs more understanding. Here, we demonstrate that MondoA, but not its paralogue ChREBP, is the predominant glucose-responsive transcription factor in human pancreatic beta EndoC-βH1 cells and in human islets. In high glucose conditions, MondoA shuttles to the nucleus where it is required for the induction of the glucose-responsive genes ARRDC4 and TXNIP, the latter being a protein strongly linked to beta-cell dysfunction and diabetes. Importantly, increasing cAMP signaling in human beta cells, using forskolin or the GLP-1 mimetic Exendin-4, inhibits the shuttling of MondoA and potently inhibits TXNIP and ARRDC4 expression. Furthermore, we demonstrate that modulating MondoA expression functionally affects glucose uptake. These results highlight MondoA as a novel target in beta cells that coordinates transcriptional response to elevated glucose levels.

Dataset Information

BxPC-3 cells: growth in different nutrients

Publications

Glutamine-dependent anapleurosis dictates glucose uptake and cell growth by regulating MondoA transcriptional activity.

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