MicroRNA-494 Regulates Endoplasmic Reticulum Stress in Endothelial Cells.
Ontology highlight
ABSTRACT:
SUBMITTER: Chatterjee N
PROVIDER: S-EPMC8311360 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Oxysterols are bioactive lipids that act as regulators of lipid metabolism, inflammation, cell viability and are involved in several diseases, including atherosclerosis. Mounting evidence linked the atherosclerosis to endothelium dysfunction; in fact, the endothelium regulates the vascular system with roles in processes such as hemostasis, cell cholesterol, hormone trafficking, signal transduction and inflammation. Several papers shed light the ability of oxysterols to induce apoptosis in different cell lines including endothelial cells. Apoptotic endothelial cell and endothelial denudation may constitute a critical step in the transition to plaque erosion and vessel thrombosis, so preventing the endothelial damaged has garnered considerable attention as a novel means of treating atherosclerosis. Endoplasmic reticulum (ER) is the site where the proteins are synthetized and folded and is necessary for most cellular activity; perturbations of ER homeostasis leads to a condition known as endoplasmic reticulum stress. This condition evokes the unfolded protein response (UPR) an adaptive pathway that aims to restore ER homeostasis. Mounting evidence suggests that chronic activation of UPR leads to cell dysfunction and death and recently has been implicated in pathogenesis of endothelial dysfunction. Autophagy is an essential catabolic mechanism that delivers misfolded proteins and damaged organelles to the lysosome for degradation, maintaining basal levels of autophagic activity it is critical for cell survival. Several evidence suggests that persistent ER stress often results in stimulation of autophagic activities, likely as a compensatory mechanism to relieve ER stress and consequently cell death. In this review, we summarize evidence for the effect of oxysterols on endothelial cells, especially focusing on oxysterols-mediated induction of endoplasmic reticulum stress.
| S-EPMC5545768 | biostudies-other
Project description:Endoplasmic reticulum (ER) stress can be triggered during in vitro embryo production and is a major obstacle to embryo survival. MicroRNA (miR)-210 is associated with cellular adaptation to cellular stress and inflammation. An experiment was conducted to understand the effects of miR-210 on in vitro embryo development, ER stress, and apoptosis; to achieve this, miR-210 was microinjected into parthenogenetically activated embryos. Our results revealed that miR-210 inhibition significantly enhanced the cleavage rate, blastocyst formation rate, and total cell number (TCN) of blastocysts, and reduced expression levels of XBP1 (p < 0.05). miR-210 inhibition greatly reduced the expression of ER stress-related genes (uXBP1, sXBP1, ATF4, and PTPN1) and Caspase 3 and increased the levels of NANOG and SOX2 (p < 0.05). A miR-210-mimic significantly decreased the cleavage, blastocyst rate, TCN, and expression levels of XBP1 compared with other groups (p < 0.05). The miR-210-mimic impaired the expression levels of uXBP1, sXBP1, ATF4, PTPN1, and Caspase 3 and decreased the expression of NANOG and SOX2 (p < 0.05). In conclusion, miR-210 plays an essential role in porcine in vitro embryo development. Therefore, we suggest that miR-210 inhibition could alleviate ER stress and reduce apoptosis to support the enhancement of in vitro embryo production.
| S-EPMC7831048 | biostudies-literature
Project description:Endoplasmic reticulum (ER) stress has been implicated in vascular endothelial dysfunction of obesity, diabetes, and hypertension. MicroRNAs play an important role in regulating ER stress. Here we show that microRNA-204 (miR-204) promotes vascular ER stress and endothelial dysfunction by targeting the Sirtuin1 (Sirt1) lysine deacetylase. Pharmacologic ER stress induced by tunicamycin upregulates miR-204 and downregulates Sirt1 in the vascular wall/endothelium in vivo and in endothelial cells in vitro. Inhibition of miR-204 protects against tunicamycin-induced vascular/endothelial ER stress, associated impairment of endothelium-dependent vasorelaxation, and preserves endothelial Sirt1. A miR-204 mimic leads to ER stress and downregulates Sirt1 in endothelial cells. Knockdown of Sirt1 in endothelial cells, and conditional deletion of endothelial Sirt1 in mice, promotes ER stress via upregulation of miR-204, whereas overexpression of Sirt1 in endothelial cells suppresses miR-204-induced ER stress. Furthermore, increase in vascular reactive oxygen species induced by ER stress is mitigated by by miR-204 inhibition. Finally, nutritional stress in the form of a Western diet promotes vascular ER stress through miR-204. These findings show that miR-204 is obligatory for vascular ER stress and ER stress-induced vascular endothelial dysfunction, and that miR-204 promotes vascular ER stress via downregulation of Sirt1.
| S-EPMC5571183 | biostudies-literature
Project description:We recently reported that ER stress plays a key role in vascular endothelial dysfunction during hypertension. In this study we aimed to elucidate the mechanisms by which ER stress induction and oxidative stress impair vascular endothelial function.We conducted in vitro studies with primary endothelial cells from coronary arteries stimulated with tunicamycin, 1?g/mL, in the presence or absence of two ER stress inhibitors: tauroursodeoxycholic acid (Tudca), 500?g/mL, and 4-phenylbutyric acid (PBA), 5mM. ER stress induction was assessed by enhanced phosphorylation of PERK and eIF2?, and increased expression of CHOP, ATF6 and Grp78/Bip. The ER stress induction increased p38 MAPK phosphorylation, Nox2/4 mRNA levels and NADPH oxidase activity, and decreased eNOS promoter activity, eNOS expression and phosphorylation, and nitrite levels. Interestingly, the inhibition of p38 MAPK pathway reduced CHOP and Bip expressions enhanced by tunicamycin and restored eNOS promoter activation as well as phosphorylation. To study the effects of ER stress induction in vivo, we used C57BL/6J mice and p47phox(-/-) mice injected with tunicamycin or saline. The ER stress induction in mice significantly impaired vascular endothelium-dependent and independent relaxation in C57BL/6J mice compared with p47phox(-/-) mice indicating NADPH oxidase activity as an intermediate for ER stress in vascular endothelial dysfunction.We conclude that chemically induced ER stress leads to a downstream enhancement of p38 MAPK and oxidative stress causing vascular endothelial dysfunction. Our results indicate that inhibition of ER stress could be a novel therapeutic strategy to attenuate vascular dysfunction during cardiovascular diseases.
| S-EPMC4086191 | biostudies-literature
Project description:Endoplasmic Reticulum (ER) stress, caused by disturbance in ER homeostasis, has been implicated in several pathological conditions such as ischemic injury, neurodegenerative disorders, metabolic diseases and more recently in inflammatory conditions. Our present study aims at understanding the role of ER stress in endothelial cell (EC) inflammation, a critical event in the pathogenesis of acute lung injury (ALI). We found that preconditioning human pulmonary artery endothelial cells (HPAEC) to ER stress either by depleting ER chaperone and signaling regulator BiP using siRNA, or specifically cleaving (inactivating) BiP using subtilase cytotoxin (SubAB), alleviates EC inflammation. The two approaches adopted to abrogate BiP function induced ATF4 protein expression and the phosphorylation of eIF2α, both markers of ER stress, which in turn resulted in blunting the activation of NF-κB, and restoring endothelial barrier integrity. Pretreatment of HPAEC with BiP siRNA inhibited thrombin-induced IκBα degradation and its resulting downstream signaling pathway involving NF-κB nuclear translocation, DNA binding, phosphorylation at serine536, transcriptional activation and subsequent expression of adhesion molecules. However, TNFα-mediated NF-κB signaling was unaffected upon BiP knockdown. In an alternative approach, SubAB-mediated inactivation of NF-κB was independent of IκBα degradation. Mechanistic analysis revealed that pretreatment of EC with SubAB interfered with the binding of the liberated NF-κB to the DNA, thereby resulting in reduced expression of adhesion molecules, cytokines and chemokines. In addition, both knockdown and inactivation of BiP stimulated actin cytoskeletal reorganization resulting in restoration of endothelial permeability. Together our studies indicate that BiP plays a central role in EC inflammation and injury via its action on NF-κB activation and regulation of vascular permeability.
| S-EPMC4214695 | biostudies-literature
Project description:Accumulation of unfolded and potentially toxic proteins in the endoplasmic reticulum (ER) activates a cell stress adaptive response, which involves a reprogramming of general gene expression. ATF4 is a master stress-induced transcription factor that orchestrates gene expression in cells treated with various ER stress inducers including those used to treat cancers. ER stress-induced ATF4 expression occurs mainly at the translational level involving the activity of the phosphorylated (P) translation initiation factor (eIF) eIF2α. While it is well established that under ER stress PeIF2α drives ATF4 expression through a specialised mode of translation re-initiation, factors (e.g. RNA-binding proteins and specific eIFs) involved in PeIF2α-mediated ATF4 translation remain unknown. Here we identified the RNA-binding protein named DDX3 as a promotor of ATF4 expression in cancer cells treated with sorafenib, an ER stress inducer used as a chemotherapeutic. Depletion experiments showed that DDX3 is required for PeIF2α-mediated ATF4 expression. Luciferase and polyribosomes assays showed that DDX3 drives ER stress-induced ATF4 mRNA expression at the translational level. Protein-interaction assays showed that DDX3 binds the eIF4F complex, which we found to be required for ER stress-induced ATF4 expression. This study thus showed that PeIF2α-mediated ATF4 mRNA translation requires DDX3 as a part of the eIF4F complex.
| S-EPMC5653821 | biostudies-literature
Project description:Atherosclerosis impacts arteries where disturbed blood flow renders the endothelium susceptible to inflammation. Cytokine activation of endothelial cells (EC) upregulates VCAM-1 receptors that target monocyte recruitment to atherosusceptible regions. Endoplasmic reticulum (ER) stress elicits EC dysregulation in metabolic syndrome. We hypothesized that ER plays a central role in mechanosensing of atherosusceptible shear stress (SS) by signaling enhanced inflammation. Aortic EC were stimulated with low-dose TNF? (0.3 ng/ml) in a microfluidic channel that produced a linear SS gradient over a 20mm field ranging from 0-16 dynes/cm2. High-resolution imaging of immunofluorescence along the monolayer provided a continuous spatial metric of EC orientation, markers of ER stress, VCAM-1 and ICAM-1 expression, and monocyte recruitment. VCAM-1 peaked at 2 dynes/cm2 and decreased to below static TNF?-stimulated levels at atheroprotective-SS of 12 dynes/cm2, whereas ICAM-1 rose to a maximum in parallel with SS. ER expansion and activation of the unfolded protein response also peaked at 2 dynes/cm2, where IRF-1-regulated VCAM-1 expression and monocyte recruitment also rose to a maximum. Silencing of PECAM-1 or key ER stress genes abrogated SS regulation of VCAM-1 transcription and monocyte recruitment. We report a novel role for ER stress in mechanoregulation at arterial regions of atherosusceptible-SS inflamed by low-dose TNF?.
| S-EPMC5557756 | biostudies-literature
Project description:Endoplasmic reticulum (ER) plays a key role in the folding, modification, and trafficking of proteins. When the homeostasis of the ER is disturbed, un/misfolded proteins accumulate in the ER which leads to ER stress. Sustained ER stress results in apoptosis, which is associated with various diseases. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a major transcription factor in redox homeostasis by regulating various genes associated with detoxification and cell-protective mechanisms. We found that Rosolic acid (RA) treatment dose-dependently activates Nrf2 in endothelial cells using the enzyme fragment complementation assay. The cytoprotective role of RA against ER stress-induced endothelial apoptosis and its molecular mechanism was explored in the present study. The Nrf2 and its target genes, as well as ER stress marker expressions, were measured by qPCR in ER stress-exposed endothelial cells. The contribution of Nrf2 in RA-mediated defense mechanism in endothelial cells was established by knockout studies using Nrf2-CRISPR/Cas9. The treatment with RA to ER stress-induced endothelial cells exhibited activation of Nrf2, as demonstrated by Nrf2 translocation and reduction of ER stress markers. We found that the Nrf2 knockout sensitized the endothelial cells against ER stress, and further, RA failed to mediate its cytoprotective effect. Proteomic studies using LC-MS/MS revealed that among the 1370 proteins detected, we found 296 differentially regulated proteins in ER stress-induced endothelial cells, and RA administration ameliorated 71 proteins towards the control levels. Of note, the ER stress in endothelial cells was attenuated by the treatment with the RA, suggesting the role of the Nrf2 activator in the pathological conditions of ER stress-associated diseases.
| S-EPMC8052152 | biostudies-literature
Project description:Although RIPK1 (receptor [TNFRSF]-interacting protein kinase 1) is emerging as a critical determinant of cell fate in response to cellular stress resulting from activation of death receptors and DNA damage, its potential role in cell response to endoplasmic reticulum (ER) stress remains undefined. Here we report that RIPK1 functions as an important prosurvival mechanism in melanoma cells undergoing pharmacological ER stress induced by tunicamycin (TM) or thapsigargin (TG) through activation of autophagy. While treatment with TM or TG upregulated RIPK1 and triggered autophagy in melanoma cells, knockdown of RIPK1 inhibited autophagy and rendered the cells sensitive to killing by TM or TG, recapitulating the effect of inhibition of autophagy. Consistently, overexpression of RIPK1 enhanced induction of autophagy and conferred resistance of melanoma cells to TM- or TG-induced cell death. Activation of MAPK8/JNK1 or MAPK9/JNK2, which phosphorylated BCL2L11/BIM leading to its dissociation from BECN1/Beclin 1, was involved in TM- or TG-induced, RIPK1-mediated activation of autophagy; whereas, activation of the transcription factor HSF1 (heat shock factor protein 1) downstream of the ERN1/IRE1-XBP1 axis of the unfolded protein response was responsible for the increase in RIPK1 in melanoma cells undergoing pharmacological ER stress. Collectively, these results identify upregulation of RIPK1 as an important resistance mechanism of melanoma cells to TM- or TG-induced ER stress by protecting against cell death through activation of autophagy, and suggest that targeting the autophagy-activating mechanism of RIPK1 may be a useful strategy to enhance sensitivity of melanoma cells to therapeutic agents that induce ER stress.
| S-EPMC4590596 | biostudies-literature
Project description:Isoforms of protein kinase B (also known as AKT) play important roles in mediating insulin and growth factor signals. Previous studies have suggested that the AKT2 isoform is critical for insulin-regulated glucose metabolism, while the role of the AKT1 isoform remains less clear. This study focuses on the effects of AKT1 on the adaptive response of pancreatic ? cells. Using a mouse model with inducible ?-cell-specific deletion of the Akt1 gene (?A1KO mice), we showed that AKT1 is involved in high-fat-diet (HFD)-induced growth and survival of ? cells but is unnecessary for them to maintain a population in the absence of metabolic stress. When unchallenged, ?A1KO mice presented the same metabolic profile and ?-cell phenotype as the control mice with an intact Akt1 gene. When metabolic stress was induced by HFD, ? cells in control mice with intact Akt1 proliferated as a compensatory mechanism for metabolic overload. Similar effects were not observed in ?A1KO mice. We further demonstrated that AKT1 protein deficiency caused endoplasmic reticulum (ER) stress and potentiated ? cells to undergo apoptosis. Our results revealed that AKT1 protein loss led to the induction of eukaryotic initiation factor 2 ? subunit (eIF2?) signaling and ER stress markers under normal-chow-fed conditions, indicating chronic low-level ER stress. Together, these data established a role for AKT1 as a growth and survival factor for adaptive ?-cell response and suggest that ER stress induction is responsible for this effect of AKT1.
| S-EPMC7225563 | biostudies-literature