scholarly journals Interactions between Endoplasmic Reticulum Stress and Autophagy: Implications for Apoptosis and Neuroplasticity-Related Proteins in Palmitic Acid-Treated Prefrontal Cells

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xiangli Xue ◽  
Feng Li ◽  
Ming Cai ◽  
Jingyun Hu ◽  
Qian Wang ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Palmitic Acid ◽  
Er Stress ◽  
Molecular Mechanisms ◽  
Apoptotic Cell ◽  
Critical Role ◽  
Sprague Dawley ◽  
Related Proteins ◽  
Phenylbutyric Acid

Lipotoxicity of palmitic acid (PA) or high-fat diets has been reported to increase endoplasmic reticulum (ER) stress and autophagy in peripheral tissue as well as apoptotic cell death. It also can lead to an AD-like pathological pattern. However, it has been unknown that PA-induced ER stress and autophagy are involved in the regulation of neuroplastic abnormalities. Here, we investigated the roles of ER stress and autophagy in apoptosis and neuroplasticity-related protein expression in PA-treated prefrontal cells. Prefrontal cells dissected from newborn Sprague-Dawley rats were treated with PA compound with ER stress inhibitor 4-phenylbutyric acid (4-PBA) and autophagy inhibitor 3-methyladenine (3-MA) or PA alone. PA promoted ER stress and autophagy and also cause apoptosis as well as a decline in the expression of neuroplasticity-related proteins. Inhibition of ER stress decreased the expressions of neuroplasticity-related proteins and reduced autophagy activation and apoptosis in PA-treated prefrontal cells. Inhibition of autophagy exacerbated apoptosis and enhanced ER stress in PA-treated prefrontal cells. The present study illustrated that both ER stress and autophagy could be involved in apoptosis and decreased neuroplasticity-related proteins, and the interaction between ER stress and autophagy may play a critical role in apoptosis in PA-treated prefrontal cells. Our results provide new insights into the molecular mechanisms in vitro of lipotoxicity in obesity-related cognitive dysfunction.

Nogo-A mediated endoplasmic reticulum stress during myocardial ischemic-reperfusion injury in diabetic rats

2021 ◽  
Author(s):  
yonghong xiong ◽  
yan leng ◽  
wei li ◽  
wenyuan li ◽  
rong chen ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Molecular Mechanisms ◽  
Myocardial Infarct ◽  
Ischemia Reperfusion ◽  
Myocardial Damage ◽  
Diabetic Rats ◽  
Myocardial Infarct Size ◽  
Sprague Dawley

Abstract Background: Diabetic myocardial ischemia reperfusion (MI/R) injury is aggravated after myocardial infarction, which leads to myocardial damage. Molecular mechanisms associated with the diabetic ischemia-related cardiac diseases are not yet fully understood. Nogo-A is an endoplasmic reticulum (ER) protein ubiquitously expressed in tissues including in the heart. However, the mechanisms that account for the Nogo-A in MI/R injury remain unknown. Methods: SD (Sprague Dawley) rats were subjected to 45 min of ischemia, followed by 3 h reperfusion. Rats were injection with streptozotocin (60mg/kg), tauroursodeoxycholic acid injection (100mg/kg) or corresponding controls just prior to MI/R. Blood and heart samples were collected at 3 h post-reperfusion. Serum LDH and CK-MB, myocardial infarct size, histopathologic changes, apotosis and ER stress were analyzed to evaluate MI/R injury. Signaling pathways were also investigated in vitro using embryonic rat cardiomyocyte-derived H9c2 cells cultures to identify underlying mechanisms for Nogo-A in diabetic MI/R injury. Results: TUDCA treatment significantly reduced Nogo-A, GRP78 and CHOP levels, diminished myocardial infarct areas, attenuated ER stress and decreased myocardial apoptosis after MI/R. ER stress signaling was significantly decreased in the TUDCA-treated MI/R group compared with controls. The effect of Nogo-A was abrogated by pretreatment with knockdown CHOP. A positive feedback loop between Nogo-A and CHOP was found leading to an enhanced ER stress in diabetic MI/R injure. Conclusions: Our data suggest that Nogo-A mediated ER stress plays a major role in diabetic MI/R injury and Nogo-A might be a key regulator of ER stress.

scholarly journals Curcumin Alleviates Palmitic Acid-Induced LOX-1 Upregulation by Suppressing Endoplasmic Reticulum Stress in HUVECs

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Ruixi Luo ◽  
Lifeng Zhao ◽  
Shuaishuai Li ◽  
Peng Chen ◽  
La Wang ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endoplasmic Reticulum ◽  
Palmitic Acid ◽  
Er Stress ◽  
Umbilical Vein ◽  
Low Density Lipoprotein ◽  
Critical Role ◽  
Density Lipoprotein ◽  
Low Density

Excessive free fatty acid- (FFA-) induced endothelial lipotoxicity is involved in the pathogenesis of atherosclerosis. Endoplasmic reticulum (ER) stress is mechanistically related to endothelial lipotoxicity. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is the major oxidatively modified low-density lipoprotein (OxLDL) receptor in endothelial cells and is highly abundant in atherosclerotic lesions. Curcumin reduces the LOX-1 expression; however, the mechanism underlying this effect remains unknown. In the current study, we explored whether curcumin ameliorates palmitic acid- (PA-) induced endothelial lipotoxicity and LOX-1 upregulation by reducing ER stress in human umbilical vein endothelial cells (HUVECs). We built endothelial lipotoxicity in vitro and found that LOX-1 was upregulated after PA stimulation, during which ER stress played an important role. Next, we observed that curcumin substantially alleviated PA-induced lipotoxicity by restoring cell viability, increasing angiogenesis, and decreasing lipid deposition. Furthermore, LOX-1 upregulation in HUVECs was blocked by curcumin, possibly via ER stress suppression. Overall, our findings demonstrated that curcumin alleviates endothelial lipotoxicity and LOX-1 upregulation, and ER stress inhibition may play a critical role in this effect.

Mesenchymal stem cells alleviate palmitic acid-induced endothelial-to-mesenchymal transition by suppressing endoplasmic reticulum stress

2020 ◽  
Vol 319 (6) ◽  
pp. E961-E980
Author(s):  
Ruixi Luo ◽  
Linzhao Li ◽  
Xiaohong Liu ◽  
Yujia Yuan ◽  
Wuzheng Zhu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Endothelial Cells ◽  
Endoplasmic Reticulum ◽  
Mesenchymal Stem Cells ◽  
Endothelial Dysfunction ◽  
Palmitic Acid ◽  
Er Stress ◽  
Critical Role ◽  
Mesenchymal Transition ◽  
Endothelial To Mesenchymal Transition

High levels of plasma free fatty acids (FFAs) lead to endothelial dysfunction (ED), which is involved in the pathogenesis of metabolic syndrome, diabetes, and atherosclerosis. Endoplasmic reticulum (ER) stress and endothelial-to-mesenchymal transition (EndMT) are demonstrated to be mechanistically related to endothelial dysfunction. Mesenchymal stem cells (MSCs) have exhibited an extraordinary cytoprotective effect on cellular lipotoxicity and vasculopathy. However, the underlying mechanisms have not been clearly defined. In the present study, we investigated whether MSCs could ameliorate palmitic acid (PA)-induced endothelial lipotoxicity by reducing ER stress and EndMT. We observed that MSC cocultures substantially alleviated PA-induced lipotoxicity in human umbilical vein endothelial cells (HUVECs). MSCs were able to restore the cell viability, increase tubule formation and migration ability, and decrease inflammation response and lipid deposition. Furthermore, PA caused endothelial-to-mesenchymal transition in HUVECs, which was abrogated by MSCs possibly through inhibiting ER stress. In addition, PA stimulated MSCs to secrete more stanniocalcin-1 (STC-1). Knocking down of STC-1 in MSCs attenuated their effects on PA-induced lipotoxicity in HUVECs. In vivo, MSC transplantation alleviated dyslipidemia and endothelial dysfunction in high-fat diet-fed Sprague–Dawley rats. MSC-treated rats showed reduced expressions of ER stress-related genes in aortas and suppressed expressions of EndMT-related proteins in rat aortic endothelial cells. Overall, our findings indicated that MSCs were able to attenuate endothelial lipotoxicity through inhibiting ER stress and EndMT, in which STC-1 secreted from MSCs may play a critical role.

Endoplasmic reticulum stress/autophagy pathway is involved in diabetes-induced neuronal apoptosis and cognitive decline in mice

2018 ◽  
Vol 132 (1) ◽  
pp. 111-125 ◽  
Author(s):  
Fei-Juan Kong ◽  
Lei-Lei Ma ◽  
Jun-Jie Guo ◽  
Lin-Hao Xu ◽  
Yun Li ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cognitive Decline ◽  
Er Stress ◽  
Hippocampal Neurons ◽  
Neuronal Apoptosis ◽  
Molecular Mechanisms ◽  
Cognitive Impairments ◽  
Public Health Problem ◽  
Diabetic Mice

Diabetes mellitus is a significant global public health problem depicting a rising prevalence worldwide. As a serious complication of diabetes, diabetes-associated cognitive decline is attracting increasing attention. However, the underlying mechanisms are yet to be fully determined. Both endoplasmic reticulum (ER) stress and autophagy have been reported to modulate neuronal survival and death and be associated with several neurodegenerative diseases. Here, a streptozotocin-induced diabetic mouse model and primary cultured mouse hippocampal neurons were employed to investigate the possible role of ER stress and autophagy in diabetes-induced neuronal apoptosis and cognitive impairments, and further explore the potential molecular mechanisms. ER stress markers GRP78 and CHOP were both enhanced in diabetic mice, as was phosphorylation of PERK, IRE1α, and JNK. In addition, the results indicated an elevated level of autophagy in diabetic mice, as demonstrated by up-regulated expressions of autophagy markers LC3-II, beclin 1 and down-regulated level of p62, and increased formation of autophagic vacuoles and LC3-II aggregates. Meanwhile, we found that these effects could be abolished by ER stress inhibitor 4-phenylbutyrate or JNK inhibitor SP600125 in vitro. Furthermore, neuronal apoptosis of diabetic mice was attenuated by pretreatment with 4-phenylbutyrate, while aggravated by application of inhibitor of autophagy bafilomycin A1 in vitro. These results suggest that ER stress pathway may be involved in diabetes-mediated neurotoxicity and promote the following cognitive impairments. More important, autophagy was induced by diabetes possibly through ER stress-mediated JNK pathway, which may protect neurons against ER stress-associated cell damages.

scholarly journals Docosahexaenoic and Eicosapentaenoic Acids Prevent Altered-Muc2 Secretion Induced by Palmitic Acid by Alleviating Endoplasmic Reticulum Stress in LS174T Goblet Cells

Nutrients ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 2179
Author(s):  
Quentin Escoula ◽  
Sandrine Bellenger ◽  
Michel Narce ◽  
Jérôme Bellenger
Keyword(s):  
Fatty Acids ◽  
Endoplasmic Reticulum ◽  
Palmitic Acid ◽  
Er Stress ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Goblet Cells ◽  
The Impact

Diets high in saturated fatty acids (FA) represent a risk factor for the development of obesity and associated metabolic disorders, partly through their impact on the epithelial cell barrier integrity. We hypothesized that unsaturated FA could alleviate saturated FA-induced endoplasmic reticulum (ER) stress occurring in intestinal secretory goblet cells, and consequently the reduced synthesis and secretion of mucins that form the protective mucus barrier. To investigate this hypothesis, we treated well-differentiated human colonic LS174T goblet cells with palmitic acid (PAL)—the most commonly used inducer of lipotoxicity in in vitro systems—or n-9, n-6, or n-3 unsaturated fatty acids alone or in co-treatment with PAL, and measured the impact of such treatments on ER stress and Muc2 production. Our results showed that only eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids protect goblet cells against ER stress-mediated altered Muc2 secretion induced by PAL, whereas neither linolenic acid nor n-9 and n-6 FA are able to provide such protection. We conclude that EPA and DHA could represent potential therapeutic nutrients against the detrimental lipotoxicity of saturated fatty acids, associated with type 2 diabetes and obesity or inflammatory bowel disease. These in vitro data remain to be explored in vivo in a context of dietary obesity.

scholarly journals Curcumin in Combination with Aerobic Exercise Improves Follicular Dysfunction via Inhibition of the Hyperandrogen-Induced IRE1α/XBP1 Endoplasmic Reticulum Stress Pathway in PCOS-Like Rats

2021 ◽  
Vol 2021 ◽  
pp. 1-22
Author(s):  
Yaling Zhang ◽  
Yajing Weng ◽  
Daojuan Wang ◽  
Rong Wang ◽  
Lihui Wang ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Aerobic Exercise ◽  
Ovarian Function ◽  
Polycystic Ovary ◽  
Ovarian Tissue ◽  
Oral Intake ◽  
Follicle Development ◽  
Sprague Dawley

Combining diet with exercise can improve health and performance. Exercise can reduce androgen excess and insulin resistance (IR) in polycystic ovary syndrome (PCOS) patients. Curcumin is also presumed to improve the follicle development disorder. Here, we investigated the effects of a combination therapy of oral intake of curcumin and exercise on hyperandrogen-induced endoplasmic reticulum (ER) stress and ovarian granulosa cell (GC) apoptosis in rats with PCOS. We generated a PCOS model via continuous dehydroepiandrosterone subcutaneous injection into the necks of Sprague Dawley rats for 35 days. PCOS-like rats then received curcumin treatment combined with aerobic (treadmill) exercise for 8 weeks. We found that compared to control rats, the ovarian tissue and ovarian GCs of hyperandrogen-induced PCOS rats showed increased levels of ER stress-related genes and proteins. Hyperandrogen-induced ovarian GC apoptosis, which was mediated by excessive ER stress and unfolded protein response (UPR) activation, could cause follicle development disorders. Both curcumin gavage and aerobic exercise improved ovarian function via inhibiting the hyperandrogen-activated ER stress IRE1α-XBP1 pathway. Dihydrotestosterone- (DHT-) induced ER stress was mitigated by curcumin/irisin or 4μ8C (an ER stress inhibitor) in primary GC culture. In this in vitro model, the strongly expressed follicular development-related genes Ar, Cyp11α1, and Cyp19α1 were also downregulated.

scholarly journals MicroRNA-494 Regulates Endoplasmic Reticulum Stress in Endothelial Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Namita Chatterjee ◽  
Eugenia Fraile-Bethencourt ◽  
Adrian Baris ◽  
Cristina Espinosa-Diez ◽  
Sudarshan Anand
Keyword(s):  
Endothelial Cells ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Stress Responses ◽  
De Novo ◽  
Umbilical Vein ◽  
Critical Role ◽  
Umbilical Vein Endothelial Cells ◽  
And Control

Defects in stress responses are important contributors in many chronic conditions including cancer, cardiovascular disease, diabetes, and obesity-driven pathologies like non-alcoholic steatohepatitis (NASH). Specifically, endoplasmic reticulum (ER) stress is linked with these pathologies and control of ER stress can ameliorate tissue damage. MicroRNAs have a critical role in regulating diverse stress responses including ER stress. Here, we show that miR-494 plays a functional role during ER stress. Pharmacological ER stress inducers (tunicamycin (TCN) and thapsigargin) and hyperglycemia robustly increase the expression of miR-494 in vitro. ATF6 impacts the primary miR-494 levels whereas all three ER stress pathways are necessary for the increase in mature miR-494. Surprisingly, miR-494 pretreatment dampens the induction and magnitude of ER stress in response to TCN in endothelial cells and increases cell viability. Conversely, inhibition of miR-494 increases ER stress de novo and amplifies the effects of ER stress inducers. Using Mass Spectrometry (TMT-MS) we identified 23 proteins that are downregulated by both TCN and miR-494 in cultured human umbilical vein endothelial cells. Among these, we found 6 transcripts which harbor a putative miR-494 binding site. We validated the anti-apoptotic gene BIRC5 (survivin) and GINS4 as targets of miR-494 during ER stress. In summary, our data indicates that ER stress driven miR-494 may act in a feedback inhibitory loop to dampen downstream ER stress signaling.

Curcumin attenuates palmitic acid-induced cell apoptosis by inhibiting endoplasmic reticulum stress in H9C2 cardiomyocytes

2019 ◽  
Vol 38 (6) ◽  
pp. 655-664 ◽  
Author(s):  
G Guan ◽  
L Lei ◽  
Q Lv ◽  
Y Gong ◽  
L Yang
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Expression ◽  
Cell Viability ◽  
Palmitic Acid ◽  
Er Stress ◽  
Diabetic Cardiomyopathy ◽  
Molecular Mechanisms ◽  
Caspase 3 ◽  
Protective Action ◽  
H9c2 Cardiomyocytes

Diabetic cardiomyopathy is mediated by multiple molecular mechanisms including endoplasmic reticulum (ER) stress. Curcumin, a phenolic compound, has cytoprotective properties, but its potential protective action against diabetic cardiomyopathy and the related molecular mechanisms are not fully elucidated. In this study, we evaluated the effects of curcumin on cell viability and apoptosis in palmitic acid (PA)-treated H9C2 cardiomyocytes and investigated the signaling pathways involved. Treatment with PA reduced cell viability, induced apoptosis, enhanced apoptosis-related protein expression (Caspase 3 and BCL-2 associated X protein (BAX)), and activated ER stress marker protein expression (glucose-regulated protein 78 (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP)). Curcumin attenuated PA-induced reduction in cell viability and activation of apoptosis, Caspase 3 activity, BAX, CHOP, and GRP78 expression. 4-Phenylbutyric acid (4-PBA) attenuated the PA-induced effects on cell viability and apoptosis, similar to curcumin. Both curcumin and 4-PBA also attenuated PA-induced increase in ER stress protein (CHOP and GRP78) expression. Curcumin also protected against cytotoxicity, apoptosis, and ER stress induced by thapsigargin. These findings indicate that PA triggers apoptosis in H9C2 cells via ER stress pathways and curcumin protects against this phenomenon.

scholarly journals Nck-dependent Activation of Extracellular Signal-regulated Kinase-1 and Regulation of Cell Survival during Endoplasmic Reticulum Stress

2004 ◽  
Vol 15 (9) ◽  
pp. 4248-4260 ◽  
Author(s):  
Duc Thang Nguyên ◽  
Sem Kebache ◽  
Ali Fazel ◽  
Hetty N. Wong ◽  
Sarah Jenna ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Kinase ◽  
Er Stress ◽  
Cell Survival ◽  
Mapk Pathway ◽  
Critical Role ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal

In response to stress, the endoplasmic reticulum (ER) signaling machinery triggers the inhibition of protein synthesis and up-regulation of genes whose products are involved in protein folding, cell cycle exit, and/or apoptosis. We demonstrate that the misfolding agents azetidine-2-carboxylic acid (Azc) and tunicamycin initiate signaling from the ER, resulting in the activation of Jun-N-terminal kinase, p44MAPK/extracellular signal-regulated kinase-1 (ERK-1), and p38MAPK through IRE1α-dependent mechanisms. To characterize the ER proximal signaling events involved, immuno-isolated ER membranes from rat fibroblasts treated with ER stress inducers were used to reconstitute the activation of the stress-activated protein kinase/mitogen-activate protein kinase (MAPK) pathways in vitro. This allowed us to demonstrate a role for the SH2/SH3 domain containing adaptor Nck in ERK-1 activation after Azc treatment. We also show both in vitro and in vivo that under basal conditions ER-associated Nck represses ERK-1 activation and that upon ER stress this pool of Nck dissociates from the ER membrane to allow ERK-1 activation. Moreover, under the same conditions, Nck-null cells elicit a stronger ERK-1 activation in response to Azc stress, thus, correlating with an enhanced survival phenotype. These data delineate a novel mechanism for the regulation of ER stress signaling to the MAPK pathway and demonstrate a critical role for Nck in ER stress and cell survival.

scholarly journals Selenoprotein V Protects Against Oxidative Stress, Endoplasmic Reticulum Stress, and Apoptosis

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1858-1858
Author(s):  
Xu Zhang ◽  
Wei Xiong ◽  
Jiaqiang Huang ◽  
Xin Gen Lei
Keyword(s):  
Oxidative Stress ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Caspase 9 ◽  
Funding Sources ◽  
Control Plasmid ◽  
Selenoprotein V ◽  
Related Proteins

Abstract Objectives Selenoprotein V (SELENOV) contains a thioredoxin-like fold and a conserved CxxU motif with a potential redox function. Three experiments were performed to assess its in vivo and in vitro roles and mechanisms in coping with different oxidant insults. Methods In Expt.1, SELENOV knockout (KO) and wildtype (WT) mice (male, 8-wk old) were given an IP injection of saline, diquat (DQ, 12.5 mg/kg), or acetaminophen (APAP, 300 mg/kg) (n = 10), and killed 5 h after the injection to collect liver and blood. In Expt. 2, primary hepatocytes were isolated from the 2 genotypes, cultured in complete Williams's medium E, and treated with DQ (0, 0.25 and 0.75 mM) and APAP (0, 1, 3, and 6 mM) for 12 h. In Expt. 3, 293 T cells were transfected with a control plasmid (GFP) or the plasmid containing Selenov gene (full length, OE) and treated with APAP (0, 1, 2, and 4 mM) for 24 h or H2O2 (0.1, 0.2, and 0.4 mM) for 12 h. Results In Expt. 1, the DQ and APAP injections caused greater (P < 0.05) rises in serum alanine aminotransferase activities, hepatic malondialdehyde (MDA) and carbonyl contents, endoplasmic reticulum (ER) stress-related proteins (BIP and CHOP), apoptosis-related proteins (FAK and caspase 9), and 3-nitrotyrosine, along with lower total anti-oxidizing-capability (T-AOC) and severer hepatocyte necrosis in the central lobular areas, in the KO than in the WT. In Expt. 2, the DQ and APAP treatments induced elevated (P < 0.05) cell death (20–40%), MDA contents (25–35%), and decreased (P < 0.05) T-AOC (50–65%) in the KO hepatocytes than in the WT cells. The KO hepatocytes treated with APAP displayed a sharp decline (P < 0.05) in cellular total respiration ability than the WT cells. In Expt. 3, the OE cells had greater viability and T-AOC and lower reactive oxygen species, MDA, and carbonyl contents after the APAP and H2O2 exposures (all at P < 0.05) than the controls. Moreover, the OE cells had greater (P < 0.05) redox enzyme activities (GPX, TrxR, and SOD), and lower (P < 0.05) expressions of ER stress-related genes (Atf4, Atf6, Bip, Xpp1t, Xbp1s, and Chop) and proteins (BIP, CHOP, FAK, caspase 9) than the controls after the treatment of H2O2 (0.4 mM). Conclusions Our data revealed the in vivo and in vitro roles and mechanisms of SELENOV in protecting against oxidative stress, ER stress, and apoptosis induced by pro-oxidants. Funding Sources This research is supported in part by an NSFC grant #31,320,103,920.

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