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Updated: Feb 22, 2026
Isolated Pancreatic Islet Treatment and Apoptosis Measurement
Published on: May 2, 2025
A Sustained Activation of Pancreatic NMDARs Is a Novel Factor of β-Cell Apoptosis and Dysfunction
Xiao-Ting Huang1, Shao-Jie Yue2, Chen Li3
1Department of Physiology, Xiangya School of Medicine, Central South University, Changsha, Hunan 410078, China.
Abstract:
Type 2 diabetes, which features β-cell failure, is caused by the decrease of β-cell mass and insulin secretory function. Current treatments fail to halt the decrease of functional β-cell mass. Strategies to prevent β-cell apoptosis and dysfunction are highly desirable. Recently, our group and others have reported that blockade of N-methyl-d-aspartate receptors (NMDARs) in the islets has been proposed to prevent the progress of type 2 diabetes through improving β-cell function. It suggests that a sustained activation of the NMDARs may exhibit deleterious effect on β-cells. However, the exact functional impact and mechanism of the sustained NMDAR stimulation on islet β-cells remains unclear. Here, we identify a sustained activation of pancreatic NMDARs as a novel factor of apoptotic β-cell death and function. The sustained treatment with NMDA results in an increase of intracellular [Ca2+] and reactive oxygen species, subsequently induces mitochondrial membrane potential depolarization and a decrease of oxidative phosphorylation expression, and then impairs the mitochondrial function of β-cells. NMDA specifically induces the mitochondrial-dependent pathway of apoptosis in β-cells through upregulation of the proapoptotic Bim and Bax, and downregulation of antiapoptotic Bcl-2. Furthermore, a sustained stimulation of NMDARs impairs β-cell insulin secretion through decrease of pancreatic duodenal homeobox-1 (Pdx-1) and adenosine triphosphate synthesis. The activation of nuclear factor-κB partly contributes to the reduction of Pdx-1 expression induced by overstimulation of NMDARs. In conclusion, we show that the sustained stimulation of NMDARs is a novel mediator of apoptotic signaling and β-cell dysfunction, providing a mechanistic insight into the pathological role of NMDARs activation in diabetes.
Insights
Sustained activation of N-methyl-d-aspartate receptors (NMDARs) in pancreatic cells triggers apoptosis and dysfunction, worsening type 2 diabetes. This research reveals NMDAR overstimulation as a key factor in beta-cell failure.
Area of Science:
- Endocrinology
- Molecular Biology
- Diabetes Research
Background:
- Type 2 diabetes is characterized by beta-cell failure, decreased beta-cell mass, and impaired insulin secretion.
- Current treatments do not prevent the decline of functional beta-cell mass.
- N-methyl-d-aspartate receptors (NMDARs) in islets have been implicated in type 2 diabetes progression, but their precise role in beta-cell dysfunction remains unclear.
Purpose of the Study:
- To investigate the functional impact and underlying mechanisms of sustained NMDAR stimulation on pancreatic beta-cells.
- To identify NMDAR activation as a potential factor in apoptotic beta-cell death and dysfunction.
Main Methods:
- Sustained treatment of pancreatic cells with NMDA (N-methyl-D-aspartate).
- Assessment of intracellular calcium ([Ca2+]) and reactive oxygen species (ROS) levels.
- Analysis of mitochondrial function, including membrane potential and oxidative phosphorylation.
- Evaluation of apoptotic pathways (Bim, Bax, Bcl-2) and insulin secretion markers (Pdx-1, ATP synthesis).
- Investigation of the role of nuclear factor-kappa B (NF-κB) activation.
Main Results:
- Sustained NMDA treatment increased intracellular [Ca2+] and ROS, leading to mitochondrial dysfunction and apoptosis via the mitochondrial-dependent pathway.
- NMDA stimulation upregulated proapoptotic proteins (Bim, Bax) and downregulated antiapoptotic protein (Bcl-2).
- Impaired beta-cell insulin secretion was observed, linked to decreased Pdx-1 expression and ATP synthesis, partly mediated by NF-κB activation.
Conclusions:
- Sustained NMDAR stimulation is a novel mediator of beta-cell apoptosis and dysfunction.
- This study provides mechanistic insights into the pathological role of NMDAR overactivation in type 2 diabetes.
- Targeting NMDARs may offer a strategy to prevent beta-cell loss and improve function in diabetes.
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