Related Experiment Video

Updated: Jul 2, 2026

Isolated Pancreatic Islet Treatment and Apoptosis Measurement
09:36

Isolated Pancreatic Islet Treatment and Apoptosis Measurement

Published on: May 2, 2025

JunB Inhibits ER Stress and Apoptosis in Pancreatic Beta Cells

Esteban N Gurzov1, Fernanda Ortis, Latifa Bakiri

  • 1Laboratory of Experimental Medicine, Université Libre de Bruxelles (ULB), Brussels, Belgium.

Plos One
|August 22, 2008
PubMed

Insights

The transcription factor JunB protects pancreatic beta-cells from apoptosis in type 1 diabetes. Reducing JunB levels increases cell death from cytokine and ER stress, while increasing JunB offers protection.

Area of Science:

  • Immunology
  • Endocrinology
  • Molecular Biology

Background:

  • Cytokines promote pancreatic beta-cell apoptosis in type 1 diabetes (T1D) by altering gene expression.
  • The transcription factor Activator Protein-1 (AP-1) is crucial in regulating inflammation and apoptosis.

Purpose of the Study:

  • To investigate the role of the AP-1 subunit JunB in cytokine-induced beta-cell dysfunction and death.
  • To understand JunB's protective mechanisms against endoplasmic reticulum (ER) stress.

Main Methods:

  • Utilized RNA interference (RNAi) to knock down JunB expression in INS-1E cells and primary rat beta-cells.
  • Employed adenoviral vectors for JunB overexpression.
  • Assessed apoptosis, inducible nitric oxide synthase (iNOS) expression, and ER stress markers.
  • Tested sensitivity to the chemical ER stressor cyclopiazonic acid (CPA).

Main Results:

  • Cytokines (IL-1beta+IFN-gamma) transiently upregulated JunB via NF-kappaB activation.
  • JunB knockdown exacerbated cytokine-induced iNOS expression, ER stress, and apoptosis.
  • JunB-deficient cells showed increased sensitivity to ER stress.
  • JunB overexpression protected beta-cells from cytokine-induced apoptosis and reduced stress markers.

Conclusions:

  • JunB acts as a novel, unexpected regulator of defense against cytokine- and ER stress-induced apoptosis in beta-cells.
  • JunB plays a protective role in maintaining beta-cell function and survival under inflammatory conditions relevant to T1D.

More Related Videos

A High-content In Vitro Pancreatic Islet β-cell Replication Discovery Platform09:35

A High-content In Vitro Pancreatic Islet β-cell Replication Discovery Platform

Published on: July 16, 2016

Related Concept Videos

Glucose Homeostasis: Pancreatic Islets and Insulin Secretion01:27

Glucose Homeostasis: Pancreatic Islets and Insulin Secretion

The pancreatic islets comprising only 1%-2% of the volume are highly vascularized and innervated mini-organs. They contain five endocrine cell types, including β cells that secrete insulin, which is synthesized as a single polypeptide chain, preproinsulin, processed to proinsulin, and finally to insulin and C-peptide. This process is complex and regulated, involving the Golgi complex, the endoplasmic reticulum, and the secretory granules of the β cell.
Insulin and C-peptide are co-secreted in...
Insulin Secretory Vesicles01:05

Insulin Secretory Vesicles

Insulin secretory vesicles release insulin to stimulate blood glucose uptake and regulate carbohydrate metabolism. When the blood glucose levels increase, glucose enters the pancreatic β-islet cells through glucose transporters. Once inside, glucose is metabolized through glycolysis, the citric acid cycle, and the electron transport chain, producing ATP. This increase in ATP concentration closes ATP-sensitive potassium channels, leading to depolarization of the membrane and the opening of...
Role of ER in the Secretory Pathway01:17

Role of ER in the Secretory Pathway

Eukaryotic cells have a special pathway that enables communication between various intracellular membrane-bound compartments and also with the extracellular environment. This pathway is termed as the secretory pathway.
Components of the secretory pathway
About a third of proteins synthesized in the cell are sorted via the secretory route. They shuffle between different compartments in membrane-bound vesicles until they reach their final destination. The main intracellular compartments involved...
Cells and Secretions of the Pancreas01:16

Cells and Secretions of the Pancreas

The pancreas, a vital organ within the abdominal cavity, plays dual roles in the digestive and endocrine systems, collaborating with exocrine and endocrine cells to maintain optimal digestion and blood sugar levels.
Exocrine function is carried out by acinar cells, organized into clusters known as acini. These cells contribute to digestion by releasing substantial quantities of enzyme-rich, alkaline digestive juices.
Concurrently, the dispersed clusters of endocrine cells throughout the...
Hormones Regulating Blood Glucose01:16

Hormones Regulating Blood Glucose

Insulin is released by beta cells of the pancreas when blood glucose levels are high. It facilitates glucose absorption and utilization in insulin-dependent cells with insulin receptors on their plasma membranes. Insulin promotes glucose uptake by increasing the number of glucose transport proteins in the cell membrane, allowing glucose to enter the cell. As a result, glucose utilization and ATP production are enhanced.
In addition to accelerating glucose uptake and utilization, insulin has...
Cell Specific Gene Expression01:58

Cell Specific Gene Expression

Multicellular organisms contain a variety of structurally and functionally distinct cell types, but the DNA in all the cells originated from the same parent cells. The differences in the cells can be attributed to the differential gene expression. Liver cells, whose functions include detoxification of blood, production of bile to metabolize fats, and synthesis of proteins essential for metabolism, must express a specific set of genes to perform their functions. Gene expression also varies with...