Abstract
Although the mechanisms by which glucose regulates insulin secretion from pancreatic β-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 paralog carbohydrate-responsive element-binding protein, is the predominant glucose-responsive transcription factor in human pancreatic β-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 arrestin domain-containing protein 4 (ARRDC4) and thioredoxin interacting protein (TXNIP), the latter being a protein strongly linked to β-cell dysfunction and diabetes. Importantly, increasing cAMP signaling in human β-cells, using forskolin or the glucagon-like peptide 1 mimetic Exendin-4, inhibits the shuttling of MondoA and potently inhibits TXNIP and ARRDC4 expression. Furthermore, we demonstrate that silencing MondoA expression improves glucose uptake in EndoC-βH1 cells. These results highlight MondoA as a novel target in β-cells that coordinates transcriptional response to elevated glucose levels.
© 2017 by the American Diabetes Association.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Active Transport, Cell Nucleus / drug effects
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Animals
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Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / antagonists & inhibitors
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Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / genetics
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Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / metabolism*
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Carrier Proteins / genetics
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Carrier Proteins / metabolism
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Cell Line
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Cyclic AMP / metabolism
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Exenatide
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Gene Expression Regulation* / drug effects
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Glucose / metabolism*
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Humans
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Incretins / pharmacology
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Insulin / metabolism*
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Insulin Secretion
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Insulin-Secreting Cells / drug effects
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Insulin-Secreting Cells / metabolism*
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Intracellular Signaling Peptides and Proteins / genetics
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Intracellular Signaling Peptides and Proteins / metabolism
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Mice, Inbred C57BL
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Mice, Knockout
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Middle Aged
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Peptides / pharmacology
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RNA Interference
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Second Messenger Systems* / drug effects
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Thioredoxins / genetics
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Thioredoxins / metabolism
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Tissue Culture Techniques
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Venoms / pharmacology
Substances
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Arrdc4 protein, mouse
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Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
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Carrier Proteins
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Incretins
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Insulin
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Intracellular Signaling Peptides and Proteins
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MLXIP protein, human
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MondoA protein, mouse
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Peptides
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TXNIP protein, human
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Txnip protein, mouse
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Venoms
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Thioredoxins
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Exenatide
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Cyclic AMP
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Glucose