scholarly journals 3β-Hydroxysteroid-Δ24 Reductase (DHCR24) Protects Pancreatic β Cells from Endoplasmic Reticulum Stress-Induced Apoptosis by Scavenging Excessive Intracellular Reactive Oxygen Species

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yang Li ◽  
Xude Wang ◽  
Baoyu Yang ◽  
Haozhen Wang ◽  
Zhenzhong Ma ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Reactive Oxygen ◽  
Intracellular Reactive Oxygen Species ◽  
Control Group ◽  
Oxygen Species ◽  
Protein Levels ◽  
Cell Dysfunction ◽  
Induced Apoptosis

There is accumulating evidence showing that apoptosis induced by endoplasmic reticulum (ER) stress plays a key role in pancreatic β cell dysfunction and insulin resistance. 3β-Hydroxysteroid-Δ24 Reductase (DHCR24) is a multifunctional enzyme located in the endoplasmic reticulum (ER), which has been previously shown to protect neuronal cells from ER stress-induced apoptosis. However, the role of DHCR24 in type 2 diabetes is only incompletely understood so far. In the present study, we induced ER stress by tunicamycin (TM) treatment and showed that infection of MIN6 cells with Ad-DHCR24-myc rendered these cells resistant to caspase-3-mediated apoptosis induced by TM, while cells transfected with siRNAs targeting DHCR24 were more sensitive to TM. Western blot analysis showed that TM treatment induced upregulation of Bip protein levels in both cells infected with Ad-LacZ (the control group) and Ad-DHCR24-myc, indicating substantial ER stress. Cells infected with Ad-LacZ exhibited a rapid and strong activation of ATF6 and p38, peaking at 3 h after TM exposure. Conversely, cells infected with Ad-DHCR24-myc showed a higher and more sustained activation of ATF6 and Bip than control cells. DHCR24 overexpression also inhibited the generation of intracellular reactive oxygen species (ROS) induced by ER stress and protected cells from apoptosis caused by treatment with both cholesterol and hydrogen peroxide. In summary, these data demonstrate, for the first time, that DHCR24 protects pancreatic β cells from apoptosis induced by ER stress.

scholarly journals Selective Activation of Endoplasmic Reticulum Stress by Reactive-Oxygen-Species-Mediated Ochratoxin A-Induced Apoptosis in Tubular Epithelial Cells

2021 ◽  
Vol 22 (20) ◽  
pp. 10951
Author(s):  
Chong-Sun Khoi ◽  
Yu-Wen Lin ◽  
Jia-Huang Chen ◽  
Biing-Hui Liu ◽  
Tzu-Yu Lin ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Ochratoxin A ◽  
Reactive Oxygen ◽  
Underlying Mechanism ◽  
Oxygen Species ◽  
Food And Feed ◽  
Renal Proximal Tubular Cells ◽  
Induced Apoptosis

Ochratoxin A (OTA), one of the major food-borne mycotoxins, impacts the health of humans and livestock by contaminating food and feed. However, the underlying mechanism of OTA nephrotoxicity remains unknown. This study demonstrated that OTA induced apoptosis through selective endoplasmic reticulum (ER) stress activation in human renal proximal tubular cells (HK-2). OTA increased ER-stress-related JNK and precursor caspase-4 cleavage apoptotic pathways. Further study revealed that OTA increased reactive oxygen species (ROS) levels, and N-acetyl cysteine (NAC) could reduce OTA-induced JNK-related apoptosis and ROS levels in HK-2 cells. Our results demonstrate that OTA induced ER stress-related apoptosis through an ROS-mediated pathway. This study provides new evidence to clarify the mechanism of OTA-induced nephrotoxicity.

scholarly journals High glucose promotes apoptosis and autophagy of MC3T3-E1 osteoblasts

2020 ◽  
Author(s):  
Pei Zhang ◽  
Jing Liao ◽  
Xiaoju Wang ◽  
Zhengping Feng
Keyword(s):  
Reactive Oxygen Species ◽  
High Glucose ◽  
Mitochondrial Membrane ◽  
Metabolic Diseases ◽  
Reactive Oxygen ◽  
Intracellular Reactive Oxygen Species ◽  
Control Group ◽  
Oxygen Species ◽  
Glucose Fluctuation ◽  
High Glucose Group

IntroductionDiabetes and osteoporosis are common metabolic diseases. Abnormal high glucose can lead to the apoptosis of osteoblasts. Autophagy is a highly conserved cellular process that degrades proteins or organelles. In the present study, we comparatively analyzed the effects of high glucose and glucose fluctuation on apoptosis and autophagy of MC3T3-E1 osteoblasts.Material and methodsMC3T3-E1 cells were respectively treated with different concentrations of D-glucose: 5.5 mM for the control group, 25 mM for the high glucose group and 5.5/25 mM for the glucose fluctuation group.ResultsHigh glucose and glucose fluctuation decreased MC3T3-E1 proliferation and activated autophagy. Also, high glucose and glucose fluctuation might induce the production of reactive oxygen species, decline the mitochondrial membrane potential and trigger apoptosis. The differences in the glucose fluctuation treatment group were more significant. Moreover, N-acetylcysteine, an antioxidant reagent, dramatically eliminated the intracellular reactive oxygen species induced by high glucose and glucose fluctuation, and significantly inhibited the autophagy and apoptosis in MC3T3-E1 osteoblasts. Furthermore, treatment with chloroquine, an inhibitor of autophagy, significantly increased the apoptosis of MC3T3-E1 osteoblasts.ConclusionsHigh glucose, especially high glucose fluctuation, inhibits proliferation and promotes apoptosis and autophagy of MC3T3-E1 osteoblasts. This may occur through inducing oxidative stress and mitochondrial damage in the osteoblasts.

Reduced levels of intracellular reactive oxygen species and apoptotic status are not correlated with increases in cryotolerance of bovine embryos produced in vitro in the presence of antioxidants

2014 ◽  
Vol 26 (6) ◽  
pp. 797 ◽  
Author(s):  
Nathália A. S. Rocha-Frigoni ◽  
Beatriz C. S. Leão ◽  
Ériklis Nogueira ◽  
Mônica F. Accorsi ◽  
Gisele Z. Mingoti
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Intracellular Reactive Oxygen Species ◽  
Control Group ◽  
Bovine Embryo ◽  
Oxygen Species ◽  
Antioxidant Supplementation ◽  
In Vitro Production ◽  
Intracellular Ros

The effects of intracellular (cysteine and β-mercaptoethanol) and extracellular (catalase) antioxidant supplementation at different times during in vitro production (IVM and/or in vitro culture (IVC)) on bovine embryo development, intracellular reactive oxygen species (ROS) levels, apoptosis and re-expansion rates after a vitrification–thawing process were examined. Blastocyst frequencies were not affected by either antioxidant supplementation (40.5%–56.4%) or the timing of supplementation (41.7%–55.4%) compared with control (48.7%; P > 0.05). Similarly, antioxidants and the moment of supplementation did not affect (P > 0.05) the total number of blastomeres (86.2–90.5 and 84.4–90.5, respectively) compared with control (85.7). However, the percentage of apoptotic cells was reduced (P < 0.05) in groups supplemented during IVM (1.7%), IVC (2.0%) or both (1.8%) compared with control (4.3%). Intracellular ROS levels measured in Day 7 blastocysts were reduced (P < 0.05) in all groups (0.60–0.78), with the exception of the group supplemented with β-mercaptoethanol during IVC (0.88), which did not differ (P > 0.05) from that in the control group (1.00). Re-expansion rates were not affected (P > 0.05) by the treatments (50.0%–93.0%). In conclusion, antioxidant supplementation during IVM and/or IVC reduces intracellular ROS and the rate of apoptosis; however, supplementation does not increase embryonic development and survival after vitrification.

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