scholarly journals Hyperglycemia Induces Endoplasmic Reticulum Stress in Atrial Cardiomyocytes, and Mitofusin-2 Downregulation Prevents Mitochondrial Dysfunction and Subsequent Cell Death

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Ming Yuan ◽  
Mengqi Gong ◽  
Zhiwei Zhang ◽  
Lei Meng ◽  
Gary Tse ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Endoplasmic Reticulum ◽  
Cell Death ◽  
Er Stress ◽  
Mitochondrial Dysfunction ◽  
High Glucose ◽  
Atrial Remodeling ◽  
Mitofusin 2 ◽  
Mitochondrial Oxidative Stress ◽  
Atrial Cardiomyocytes

Mitochondrial oxidative stress and dysfunction play an important role of atrial remodeling and atrial fibrillation (AF) in diabetes mellitus. Endoplasmic reticulum (ER) stress has been linked to both physiological and pathological states including diabetes. The aim of this project is to explore the roles of ER stress in hyperglycemia-induced mitochondrial dysfunction and cell death of atrial cardiomyocytes. High glucose upregulated ER stress, mitochondrial oxidative stress, and mitochondria-associated ER membrane (MAM)- enriched proteins (such as glucose-regulated protein 75 (GRP75) and mitofusin-2 (Mfn2)) of primary cardiomyocytes in vitro. Sodium phenylbutyrate (4-PBA) prevented the above changes. Silencing of Mfn2 in HL-1 cells decreased the Ca2+ transfer from ER to mitochondria under ER stress conditions, which were induced by the ER stress agonist, tunicamycin (TM). Electron microscopy data suggested that Mfn2 siRNA significantly disrupted ER-mitochondria tethering in ER stress-injured HL-1 cells. Mfn2 silencing attenuated mitochondrial oxidative stress and Ca2+ overload, increased mitochondrial membrane potential and mitochondrial oxygen consumption, and protected cells from TM-induced apoptosis. In summary, Mfn2 plays an important role in high glucose-induced ER stress in atrial cardiomyocytes, and Mfn2 silencing prevents mitochondrial Ca2+ overload-mediated mitochondrial dysfunction, thereby decreasing ER stress-mediated cardiomyocyte cell death.

scholarly journals IP3R1/GRP75/VDAC1 complex mediated endoplasmic reticulum stress-mitochondrial oxidative stress in diabetic atrial remodeling

EP Europace ◽  
2021 ◽  
Vol 23 (Supplement_3) ◽  
Author(s):  
T Liu ◽  
M Yuan ◽  
M Gong ◽  
J He ◽  
Z Zhang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Atrial Fibrillation ◽  
Endoplasmic Reticulum ◽  
Endoplasmic Reticulum Stress ◽  
Er Stress ◽  
Conditional Knockout ◽  
Proximity Ligation Assay ◽  
Atrial Remodeling ◽  
Mitochondrial Oxidative Stress

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): National Natural Science Foundation of China Background Mitochondrial oxidative stress is an important mechanism of atrial remodeling and atrial fibrillation (AF) in the setting of diabetes. Currently, endoplasmic reticulum (ER) stress is regarded as the key link from homeostasis to dysfunction, and is a central feature of metabolic diseases such as type 2 diabetes. However, the molecular mechanisms underlying these processes have not been fully elucidated. Objective To explore the potential role of ER stress-mitochondrial oxidative stress in atrial remodeling and AF induction in diabetes. Methods  Mouse atrial cardiomyocytes (HL-1 cells) , type 2 diabetic rats and GRP75 conditional knockout mice were used as models systems. These findings were correlated with biomarker findings in human diabetic patients with confirmed atrial fibrillation. Results  In the diabetic rat atria, significant ER stress was observed. Treatment with tunicamycin (TM), an ER stress agonist, mass spectrometry (MS) demonstrated many known ER stress and calmodulin proteins, including Heat shock protein family A (Hsp70) member (Hspa) 5 (GRP78) and Hspa9 (GRP75) and in situ proximity ligation assay (PLA) indicated that TM led to increased protein expression of the IP3R1 (inositol 1,4,5-trisphosphate receptors 1)/GRP75 (glucose-regulated protein 75)/VDAC1 (voltage-dependent anion channel 1) complex in HL-1 cells. Silencing of GRP75 using siRNA in HL-1 cells and GRP75 conditional knockout in our mouse model led to impaired calcium transport from the ER to mitochondria, and alleviated mitochondrial oxidative stress and calcium overload. Moreover, GRP75 deficiency attenuates atrial remodeling and AF progression in Myh6-Cre+/Hspa9flox/flox + TM mice. Conclusions  The IP3R1/GRP75/VDAC1 complex mediates endoplasmic reticulum stress-mitochondrial oxidative stress plays an important role in diabetic atrial remodeling. Abstract Figure

scholarly journals The Interplay of Mitochondrial Oxidative Stress and Endoplasmic Reticulum Stress in Cardiovascular Fibrosis in Obese Rats

Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1274
Author(s):  
Francisco V. Souza-Neto ◽  
Sara Jiménez-González ◽  
Beatriz Delgado-Valero ◽  
Raquel Jurado-López ◽  
Marie Genty ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Control Diet ◽  
Ang Ii ◽  
Mitochondrial Oxidative Stress ◽  
Relevant Role ◽  
Male Wistar Rats ◽  
Cardiovascular Fibrosis ◽  
Stress Activation

We have evaluated the role of mitochondrial oxidative stress and its association with endoplasmic reticulum (ER) stress activation in the progression of obesity-related cardiovascular fibrosis. MitoQ (200 µM) was orally administered for 7 weeks to male Wistar rats that were fed a high-fat diet (HFD, 35% fat) or a control diet (CT, 3.5% fat). Obese animals presented cardiovascular fibrosis accompanied by increased levels of extracellular matrix proteins and profibrotic mediators. These alterations were associated with ER stress activation characterized by enhanced levels (in heart and aorta vs. CT group, respectively) of immunoglobulin binding protein (BiP; 2.1-and 2.6-fold, respectively), protein disulfide-isomerase A6 (PDIA6; 1.9-fold) and CCAAT-enhancer-binding homologous protein (CHOP; 1.5- and 1.8-fold, respectively). MitoQ treatment was able to prevent (p < 0.05) these modifications at cardiac and aortic levels. MitoQ (5 nM) and the ER stress inhibitor, 4-phenyl butyric acid (4 µM), were able to block the prooxidant and profibrotic effects of angiotensin II (Ang II, 10−6 M) in cardiac and vascular cells. Therefore, the data show a crosstalk between mitochondrial oxidative stress and ER stress activation, which mediates the development of cardiovascular fibrosis in the context of obesity and in which Ang II can play a relevant role.

scholarly journals Deltamethrin Induces Apoptosis in Cerebrum Neurons of Quail via Promoting Endoplasmic Reticulum Stress and Mitochondrial Dysfunction

2021 ◽  
Author(s):  
Pengfei Wu ◽  
Bing Han ◽  
Qingyue Yang ◽  
Siyu Li ◽  
Xiaoqiao Wang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Mitochondrial Dysfunction ◽  
Chronic Exposure ◽  
Molecular Mechanisms ◽  
Atp Content ◽  
Histological Changes ◽  
Real Time Quantitative Pcr ◽  
Induced Apoptosis

Abstract Deltamethrin (DLM) is a widely used and highly effective insecticide. DLM exposure is harmful to animal and human. Quail, as a bird model, has been widely used in the toxicology field. However, there is little information available in the literature about quail cerebrum damage caused by DLM. Here, we investigated the effect of DLM on quail cerebrum neurons. Four groups of healthy quails were assigned (10 quails in each group), respectively given 0, 15, 30, and 45 mg/kg DLM by gavage for 12 weeks. Through the measurements of quail cerebrum, it was found that DLM exposure induced obvious histological changes, oxidative stress, and neurons apoptosis. To further explore the possible molecular mechanisms, we performed real-time quantitative PCR to detect the expression of endoplasmic reticulum (ER) stress-related mRNA. In addition, we detected ATP content in quail cerebrum to evaluate the functional status of mitochondria. The study showed that DLM exposure significantly increased the expression of ER stress-related mRNA and decreased ATP content in quail cerebrum. These results suggest that chronic exposure to DLM induces apoptosis of quail cerebrum neurons via promoting ER stress and mitochondrial dysfunction. Furthermore, our results provide a novel explanation for DLM-induced apoptosis of avian cerebrum neurons.

scholarly journals Endoplasmic reticulum calcium release potentiates the ER stress and cell death caused by an oxidative stress in MCF-7 cells

2010 ◽  
Vol 79 (9) ◽  
pp. 1221-1230 ◽  
Author(s):  
Nicolas Dejeans ◽  
Nicolas Tajeddine ◽  
Raphaël Beck ◽  
Julien Verrax ◽  
Henryk Taper ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Endoplasmic Reticulum ◽  
Cell Death ◽  
Er Stress ◽  
Calcium Release ◽  
Endoplasmic Reticulum Calcium ◽  
Mcf 7

scholarly journals Damage to the Endoplasmic Reticulum and Activation of Apoptotic Machinery by Oxidative Stress in Ischemic Neurons

2005 ◽  
Vol 25 (1) ◽  
pp. 41-53 ◽  
Author(s):  
Takeshi Hayashi ◽  
Atsushi Saito ◽  
Shuzo Okuno ◽  
Michel Ferrand-Drake ◽  
Robert L Dodd ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Endoplasmic Reticulum ◽  
Cell Death ◽  
Er Stress ◽  
Neuronal Degeneration ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Wild Type ◽  
Transgenic Rats ◽  
The Brain

The endoplasmic reticulum (ER), which plays a role in apoptosis, is susceptible to oxidative stress. Because superoxide is produced in the brain after ischemia/reperfusion, oxidative injury to this organelle may be implicated in ischemic neuronal cell death. Activating transcription factor-4 (ATF-4) and C/EBP-homologous protein (CHOP), both of which are involved in apoptosis, are induced by severe ER stress. Using wild-type and human copper/zinc superoxide dismutase transgenic rats, we observed induction of these molecules in the brain after global cerebral ischemia and compared them with neuronal degeneration. In ischemic, wild-type brains, expression of ATF-4 and CHOP was increased in the hippocampal CA1 neurons that would later undergo apoptosis. Transgenic rats had a mild increase in ATF-4 and CHOP and minimal neuronal degeneration, indicating that superoxide was involved in ER stress-induced cell death. We further confirmed attenuation on induction of these molecules in transgenic mouse brains after focal ischemia. When superoxide was visualized with ethidium, signals for ATF-4 and superoxide overlapped in the same cells. Moreover, lipids in the ER were robustly peroxidized by ischemia but were attenuated in transgenic animals. This indicates that superoxide attacked and damaged the ER, and that oxidative ER damage is implicated in ischemic neuronal cell death.

scholarly journals Nicorandil attenuates high glucose-induced insulin resistance by suppressing oxidative stress-mediated ER stress PERK signaling pathway

2021 ◽  
Vol 9 (1) ◽  
pp. e001884
Author(s):  
Zhongwei Liu ◽  
Haitao Zhu ◽  
Chunhui He ◽  
Ting He ◽  
Shuo Pan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Endoplasmic Reticulum ◽  
Protein Kinase ◽  
Glucose Tolerance ◽  
Er Stress ◽  
High Glucose ◽  
Muscle Cells ◽  
Skeletal Muscle Cells

IntroductionGlucose-induced insulin resistance is a typical character of diabetes. Nicorandil is now widely used in ischemic heart disease. Nicorandil shows protective effects against oxidative and endoplasmic reticulum (ER) stress, which are involved in insulin resistance. Here, we investigated mechanisms of nicorandil’s novel pharmacological activity on insulin resistance in diabetes.Research design and methodsNicorandil was administrated to streptozotocin-induced animals with diabetes and high glucose exposed skeletal muscle cells. Insulin resistance and glucose tolerance were evaluated. Molecular mechanisms concerning oxidative stress, ER stress signaling activation and glucose uptake were assessed.ResultsNicorandil attenuated high glucose-induced insulin resistance without affecting fasting blood glucose and glucose tolerance in whole body and skeletal muscle in rats with diabetes. Nicorandil treatment suppressed protein kinase C/nicotinamide adenine dinucleotide phosphate oxidases system activities by reducing cytoplasmic free calcium level in skeletal muscle cells exposed to high glucose. As a result, the oxidative stress-mediated ER stress protein kinase RNA-like endoplasmic reticulum kinase (PERK)/eukaryotic initiation factor 2α/activating transcription factor 4/CEBP homologous protein/tribbles homolog (TRB)3 signaling pathway activation was inhibited. Nicorandil downregulated expression of TRB3 and thus facilitated Akt phosphorylation in response to insulin stimulation, leading to glucose transporter4 plasma membrane translocation which promoted glucose uptake capability of skeletal muscle cells.ConclusionsBy reducing cytoplasmic calcium, nicorandil alleviated high glucose-induced insulin resistance by inhibiting oxidative stress-mediated ER stress PERK pathway.

scholarly journals Protective Mechanisms of the Mitochondrial-Derived Peptide Humanin in Oxidative and Endoplasmic Reticulum Stress in RPE Cells

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Leonid Minasyan ◽  
Parameswaran G. Sreekumar ◽  
David R. Hinton ◽  
Ram Kannan
Keyword(s):  
Oxidative Stress ◽  
Endoplasmic Reticulum ◽  
Cell Death ◽  
Er Stress ◽  
Apoptotic Cell ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Ros Generation ◽  
Rpe Cells ◽  
Age Related

Age-related macular degeneration (AMD) is the leading cause of severe and irreversible vision loss and is characterized by progressive degeneration of the retina resulting in loss of central vision. The retinal pigment epithelium (RPE) is a critical site of pathology of AMD. Mitochondria and the endoplasmic reticulum which lie in close anatomic proximity to each other are targets of oxidative stress and endoplasmic reticulum (ER) stress, respectively, and contribute to the progression of AMD. The two organelles exhibit close interactive function via various signaling mechanisms. Evidence for ER-mitochondrial crosstalk in RPE under ER stress and signaling pathways of apoptotic cell death is presented. The role of humanin (HN), a prominent member of a newly discovered family of mitochondrial-derived peptides (MDPs) expressed from an open reading frame of mitochondrial 16S rRNA, in modulation of ER and oxidative stress in RPE is discussed. HN protected RPE cells from oxidative and ER stress-induced cell death by upregulation of mitochondrial GSH, inhibition of ROS generation, and caspase 3 and 4 activation. The underlying mechanisms of ER-mitochondrial crosstalk and modulation by exogenous HN are discussed. The therapeutic use of HN and related MDPs could potentially prove to be a valuable approach for treatment of AMD.

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