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Npas4 Is a Novel Activity–Regulated Cytoprotective Factor in Pancreatic β-Cells

Cellular homeostasis requires intrinsic sensing mechanisms to temper function in the face of prolonged activity. In the pancreatic β-cell, glucose is likely a physiological trigger that activates an adaptive response to stimulation, thereby maintaining cellular homeostasis. Immediate early genes (IE...

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Detalles Bibliográficos
Autores principales: Sabatini, Paul V., Krentz, Nicole A.J., Zarrouki, Bader, Westwell-Roper, Clara Y., Nian, Cuilan, Uy, Ryan A., Shapiro, A.M. James, Poitout, Vincent, Lynn, Francis C.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Diabetes Association 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3717850/
https://www.ncbi.nlm.nih.gov/pubmed/23656887
http://dx.doi.org/10.2337/db12-1527
Descripción
Sumario:Cellular homeostasis requires intrinsic sensing mechanisms to temper function in the face of prolonged activity. In the pancreatic β-cell, glucose is likely a physiological trigger that activates an adaptive response to stimulation, thereby maintaining cellular homeostasis. Immediate early genes (IEGs) are activated as a first line of defense in cellular homeostasis and are largely responsible for transmitting an environmental cue to a cellular response. Here we examine the regulation and function of the novel β-cell IEG, neuronal PAS domain protein 4 (Npas4). Using MIN6 cells, mouse and human islets, as well as in vivo infusions, we demonstrate that Npas4 is expressed within pancreatic islets and is upregulated by β-cell depolarizing agents. Npas4 tempers β-cell function through a direct inhibitory interaction with the insulin promoter and by blocking the potentiating effects of GLP-1 without significantly reducing glucose-stimulated secretion. Finally, Npas4 expression is induced by classical endoplasmic reticulum (ER) stressors and can prevent thapsigargin- and palmitate-induced dysfunction and cell death. These results suggest that Npas4 is a key activity-dependent regulator that improves β-cell efficiency in the face of stress. We posit that Npas4 could be a novel therapeutic target in type 2 diabetes that could both reduce ER stress and cell death and maintain basal cell function.