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Published on: January 23, 2018
Mitochondrial reactive oxygen species (ROS) inhibition ameliorates palmitate-induced INS-1 beta cell death
Ning Lin1, Hanbei Chen, Hongmei Zhang
1Department of Endocrinology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, 1665, KongJiang Road, Shanghai, 200092, China.
Abstract:
The purpose of this study is to explore the possible link between oxidative stress and endoplasmic reticulum (ER) stress in palmitate (PA) induced apoptosis of INS-1 cells, and to figure out the main source of reactive oxygen species (ROS) and the effect of ROS inhibition on the level of ER stress. In this study, INS-1 cells were exposed to PA and oleate for the indicated times. Cell viability and apoptosis were measured by MTT and ELISA; ROS was detected by the probe DCFH-DA and MitoSOX Red using flow cytometer; and the ER stress-related chaperones were measured by western blotting and real time PCR. The level of JNK phosphorylation was also measured by western blotting. The results showed that, in PA-treated cells, apoptosis increased in a dose-dependent way. ROS generation was mainly increased through mitochondrion, and ROS inhibition reduced the expression of some ER chaperones and transcription factors levels. Also, inhibition of JNK phosphorylation ameliorated PA-induced apoptosis. It is concluded that, ROS inhibition, especially inhibiting the ROS from mitochondria, may reduce the expression of some ER stress-related effectors and show a protective role in PA-induced pancreatic beta-cell apoptosis.
Insights
Oxidative stress from mitochondria contributes to pancreatic beta-cell apoptosis. Inhibiting reactive oxygen species (ROS) protects against palmitate-induced cell death and endoplasmic reticulum (ER) stress.
Area of Science:
- Molecular Biology
- Cell Biology
- Endocrinology
Background:
- Palmitate exposure induces apoptosis in pancreatic beta-cells.
- Oxidative stress and endoplasmic reticulum (ER) stress are implicated in beta-cell dysfunction.
- The precise relationship and source of reactive oxygen species (ROS) in this context require elucidation.
Purpose of the Study:
- To investigate the link between oxidative stress and ER stress in palmitate-induced INS-1 cell apoptosis.
- To identify the primary source of ROS during palmitate exposure.
- To determine the impact of ROS inhibition on ER stress markers and cell survival.
Main Methods:
- INS-1 cells were treated with palmitate (PA) and oleate.
- Cell viability and apoptosis were assessed using MTT assays and ELISA.
- ROS production was measured via DCFH-DA and MitoSOX Red probes using flow cytometry.
- ER stress markers (chaperones, transcription factors) and JNK phosphorylation were analyzed by western blotting and real-time PCR.
Main Results:
- Palmitate treatment resulted in a dose-dependent increase in apoptosis.
- Mitochondria were identified as the main source of increased ROS.
- Inhibition of ROS reduced the expression of ER stress-related chaperones and transcription factors.
- Inhibition of JNK phosphorylation attenuated palmitate-induced apoptosis.
Conclusions:
- Oxidative stress, particularly from mitochondria, plays a key role in palmitate-induced pancreatic beta-cell apoptosis.
- ROS inhibition demonstrates a protective effect by reducing ER stress markers.
- Targeting mitochondrial ROS may be a therapeutic strategy for protecting beta-cells from lipotoxicity.
