scholarly journals Activation of Cyclooxygenase-2 by ATF4 During Endoplasmic Reticulum Stress Regulates Kidney Podocyte Autophagy Induced by Lupus Nephritis

2018 ◽  
Vol 48 (2) ◽  
pp. 753-764 ◽  
Author(s):  
Juan Jin ◽  
Li Zhao ◽  
Wenli Zou ◽  
Wei Shen ◽  
Hongjuan Zhang ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Lupus Nephritis ◽  
Er Stress ◽  
Nuclear Translocation ◽  
Kidney Injury ◽  
Cyclooxygenase 2 ◽  
Enzyme Linked Immunosorbent Assay ◽  
Protein Levels ◽  
Cox 2 ◽  
Stress Pathway

Background/Aims: Autophagy plays an essential role in lupus nephritis (LN)-induced kidney injury, although the mechanism of action remains obscure. We investigated the role of cyclooxygenase-2 (COX-2) and the ATF4 endoplasmic reticulum (ER) stress pathway in LN-induced podocyte autophagy. Methods: We evaluated podocyte autophagy in a mouse model of LN. Protein levels of COX-2 and ATF4, and markers of autophagy, were evaluated by immunofluorescence and western blotting. To evaluate apoptosis, levels of PGE2 were measured by enzyme-linked immunosorbent assay. Results: LN induced kidney damage and dysfunction, which was associated with podocyte autophagy. COX-2 and the ATF4 ER stress pathway were induced by LN in cultured podocytes. Inhibition of COX-2 inhibited LN-induced autophagy in podocytes. In addition, blocking ER stress with 4-phenylbutyrate or RNAi partially counteracted COX-2 overexpression and LN-induced autophagy, suggesting that ER stress is required for LN-induced kidney autophagy. Furthermore, LN activated ATF4 and induced its nuclear translocation. Knockdown of ATF4 inhibited LN-induced COX-2 overexpression. Conclusions: Our study suggests a novel molecular mechanism by which COX2 overexpression, induced by the ATF4 ER stress pathway, contributes to LN-induced kidney autophagy and injury. These data demonstrate that COX-2 may be a potential therapeutic target against LN-induced nephropathy.

scholarly journals Rapamycin Improves Palmitate-Induced ER Stress/NFκB Pathways Associated with Stimulating Autophagy in Adipocytes

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Jiajing Yin ◽  
Liping Gu ◽  
Yufan Wang ◽  
Nengguang Fan ◽  
Yuhang Ma ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Nuclear Translocation ◽  
Kinase Inhibitor ◽  
Autophagy Flux ◽  
Protein Levels ◽  
Stress Effects ◽  
Stress Markers

Obesity-induced endoplasmic reticulum (ER) stress and inflammation lead to adipocytes dysfunction. Autophagy helps to adapt to cellular stress and involves in regulating innate inflammatory response. In present study, we examined the activity of rapamycin, a mTOR kinase inhibitor, against endoplasmic reticulum stress and inflammation in adipocytes. Anin vitromodel was used in which 3T3-L1 adipocytes were preloaded with palmitate (PA) to generate artificial hypertrophy mature adipocytes. Elevated autophagy flux and increased number of autophagosomes were observed in response to PA and rapamycin treatment. Rapamycin attenuated PA-induced PERK and IRE1-associated UPR pathways, evidenced by decreased protein levels of eIF2αphosphorylation, ATF4, CHOP, and JNK phosphorylation. Inhibiting autophagy with chloroquine (CQ) exacerbated these ER stress markers, indicating the role of autophagy in ameliorating ER stress. In addition, cotreatment of CQ abolished the anti-ER stress effects of rapamycin, which confirms the effect of rapamycin on ERs is autophagy-dependent. Furthermore, rapamycin decreased PA-induced nuclear translocation of NFκB P65 subunit, thereby NFκB-dependent inflammatory cytokines MCP-1 and IL-6 expression and secretion. In conclusion, rapamycin attenuated PA-induced ER stress/NFκB pathways to counterbalance adipocytes stress and inflammation. The beneficial of rapamycin in this context partly depends on autophagy. Stimulating autophagy may become a way to attenuate adipocytes dysfunction.

scholarly journals Maternal high-fat diet induces metabolic stress response disorders in offspring hypothalamus

2017 ◽  
Vol 59 (1) ◽  
pp. 81-92 ◽  
Author(s):  
Long The Nguyen ◽  
Sonia Saad ◽  
Yi Tan ◽  
Carol Pollock ◽  
Hui Chen
Keyword(s):  
Endoplasmic Reticulum ◽  
Body Weight ◽  
Er Stress ◽  
High Fat Diet ◽  
Maternal Obesity ◽  
Mrna Level ◽  
Metabolic Stress ◽  
High Fat ◽  
Chemical Chaperone ◽  
Protein Levels

Maternal obesity has been shown to increase the risk of obesity and related disorders in the offspring, which has been partially attributed to changes of appetite regulators in the offspring hypothalamus. On the other hand, endoplasmic reticulum (ER) stress and autophagy have been implicated in hypothalamic neuropeptide dysregulation, thus may also play important roles in such transgenerational effect. In this study, we show that offspring born to high-fat diet-fed dams showed significantly increased body weight and glucose intolerance, adiposity and plasma triglyceride level at weaning. Hypothalamic mRNA level of the orexigenic neuropeptide Y (NPY) was increased, while the levels of the anorexigenic pro-opiomelanocortin (POMC), NPY1 receptor (NPY1R) and melanocortin-4 receptor (MC4R) were significantly downregulated. In association, the expression of unfolded protein response (UPR) markers including glucose-regulated protein (GRP)94 and endoplasmic reticulum DNA J domain-containing protein (Erdj)4 was reduced. By contrast, protein levels of autophagy-related genes Atg5 and Atg7, as well as mitophagy marker Parkin, were slightly increased. The administration of 4-phenyl butyrate (PBA), a chemical chaperone of protein folding and UPR activator, in the offspring from postnatal day 4 significantly reduced their body weight, fat deposition, which were in association with increased activating transcription factor (ATF)4, immunoglobulin-binding protein (BiP) and Erdj4 mRNA as well as reduced Parkin, PTEN-induced putative kinase (PINK)1 and dynamin-related protein (Drp)1 protein expression levels. These results suggest that hypothalamic ER stress and mitophagy are among the regulatory factors of offspring metabolic changes due to maternal obesity.

scholarly journals Hepatitis C Virus Core Protein Suppresses NF-κB Activation and Cyclooxygenase-2 Expression by Direct Interaction with IκB Kinase β

2005 ◽  
Vol 79 (12) ◽  
pp. 7648-7657 ◽  
Author(s):  
Myungsoo Joo ◽  
Young S. Hahn ◽  
Minjae Kwon ◽  
Ruxana T. Sadikot ◽  
Timothy S. Blackwell ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Nuclear Translocation ◽  
Core Protein ◽  
Ectopic Expression ◽  
Cyclooxygenase 2 ◽  
Necrosis Factor Alpha ◽  
Iκb Kinase ◽  
Cox 2 ◽  
The Impact

ABSTRACT In addition to hepatocytes, hepatitis C virus (HCV) infects immune cells, including macrophages. However, little is known concerning the impact of HCV infection on cellular functions of these immune effector cells. Lipopolysaccharide (LPS) activates IκB kinase (IKK) signalsome and NF-κB, which leads to the expression of cyclooxygenase-2 (COX-2), which catalyzes production of prostaglandins, potent effectors on inflammation and possibly hepatitis. Here, we examined whether expression of HCV core interferes with IKK signalsome activity and COX-2 expression in activated macrophages. In reporter assays, HCV core inhibited NF-κB activation in RAW 264.7 and MH-S murine macrophage cell lines treated with bacterial LPS. HCV core inhibited IKK signalsome and IKKβ kinase activities induced by tumor necrosis factor alpha in HeLa cells and coexpressed IKKγ in 293 cells, respectively. HCV core was coprecipitated with IΚΚβ and prevented nuclear translocation of IKKβ. NF-κB activation by either LPS or overexpression of IKKβ was sufficient to induce robust expression of COX-2, which was markedly suppressed by ectopic expression of HCV core. Together, these data indicate that HCV core suppresses IKK signalsome activity, which blunts COX-2 expression in macrophages. Additional studies are necessary to determine whether interrupted COX-2 expression by HCV core contributes to HCV pathogenesis.

scholarly journals Upregulation of the Sarco-Endoplasmic Reticulum Calcium ATPase 1 Truncated Isoform Plays a Pathogenic Role in Alzheimer’s Disease

Cells ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1539 ◽  
Author(s):  
Bussiere ◽  
Oulès ◽  
Mary ◽  
Vaillant-Beuchot ◽  
Martin ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Neuroblastoma Cells ◽  
Amyloid Β ◽  
Aβ Oligomers ◽  
Human Neuroblastoma ◽  
Endoplasmic Reticulum Calcium ◽  
Protein Levels ◽  
Functional Consequences ◽  
Β Amyloid

Dysregulation of the Endoplasmic Reticulum (ER) Ca2+ homeostasis and subsequent ER stress activation occur in Alzheimer Disease (AD). We studied the contribution of the human truncated isoform of the sarco-endoplasmic reticulum Ca2+ ATPase 1 (S1T) to AD. We examined S1T expression in human AD-affected brains and its functional consequences in cellular and transgenic mice AD models. S1T expression is increased in sporadic AD brains and correlates with amyloid β (Aβ) and ER stress chaperone protein levels. Increased S1T expression was also observed in human neuroblastoma cells expressing Swedish-mutated β-amyloid precursor protein (βAPP) or treated with Aβ oligomers. Lentiviral overexpression of S1T enhances in return the production of APP C-terminal fragments and Aβ through specific increases of β-secretase expression and activity, and triggers neuroinflammation. We describe a molecular interplay between S1T-dependent ER Ca2+ leak, ER stress and βAPP-derived fragments that could contribute to AD setting and/or progression.

scholarly journals Endoplasmic Reticulum Stress Is Involved in Baicalin Protection on Chondrocytes From Patients With Osteoarthritis

Dose-Response ◽  
2018 ◽  
Vol 16 (4) ◽  
pp. 155932581881063 ◽  
Author(s):  
Jiangang Cao ◽  
Yu Zhang ◽  
Tianyi Wang ◽  
Bo Li
Keyword(s):  
Oxidative Stress ◽  
Endoplasmic Reticulum ◽  
Endoplasmic Reticulum Stress ◽  
Cell Viability ◽  
Er Stress ◽  
Messenger Rna ◽  
Cell Counting ◽  
Protective Effects ◽  
Gene Expressions ◽  
Protein Levels

Osteoarthritis (OA) affects elderly population worldwide and endoplasmic reticulum (ER) stress is known to be positively correlated with OA development. Previous reports prove the cytoprotective effects of baicalin on chondrocytes, whereas the mechanisms are hardly reported. Hence, we aimed to investigate the links between OA, ER stress, and baicalin. Chondrocytes from patients with OA were subjected to H2O2 treatment with or without baicalin pretreatment, and cell viability was assessed via Cell Counting Kit-8. Messenger RNA (mRNA) amounts of apoptosis-related genes (Bax, Bcl-2, and Caspase-3), extracellular matrix (ECM)-related genes (Collange I, Collange II, Aggrecan, and Sox9) and ER stress hallmarks (binding immunoglobulin protein [BiP] C/EBP homologous protein [CHOP]) were evaluated via quantitative real-time PCR. Bax, Bcl-2, BiP, and CHOP protein levels were analyzed via Western blot. Baicalin suppressed the changes in cell viability and apoptosis-related gene expressions caused by H2O2. Reactive oxygen species and glutathione/oxidized glutathione assay showed that H2O2 enhanced oxidative stress. Baicalin suppressed H2O2-induced downregulation of mRNA expression of ECM-related genes. Moreover, baicalin reduced H2O2-stimulated increase in oxidative stress and the expression of ER stress hallmarks. Endoplasmic reticulum stress inducer abolished the protective activities, whereas ER stress inhibitor did not exhibit extra protective effects. Baicalin pretreatment protected patient-derived chondrocytes from H2O2 through ER stress inhibition.

Enteroids Derived From Inflammatory Bowel Disease Patients Display Dysregulated Endoplasmic Reticulum Stress Pathways, Leading to Differential Inflammatory Responses and Dendritic Cell Maturation

2019 ◽  
Vol 14 (7) ◽  
pp. 948-961 ◽  
Author(s):  
William D Rees ◽  
Martin Stahl ◽  
Kevan Jacobson ◽  
Brian Bressler ◽  
Laura M Sly ◽  
...  
Keyword(s):  
Inflammatory Bowel Disease ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Bowel Disease ◽  
Inflammatory Responses ◽  
Human Colon ◽  
Intestinal Epithelial ◽  
Stress Changes ◽  
Inflammatory Bowel ◽  
Stress Pathway

Abstract Background and Aims Endoplasmic reticulum [ER] stress in intestinal epithelial cells [IECs] contributes to the pathogenesis of inflammatory bowel disease [IBD]. We hypothesized that ER stress changes innate signalling in human IECs, augmenting toll-like receptor [TLR] responses and inducing pro-inflammatory changes in underlying dendritic cells [DCs]. Methods Caco-2 cells and primary human colon-derived enteroid monolayers were exposed to ATP [control stressor] or thapsigargin [Tg] [ER stress inducer], and were stimulated with the TLR5 agonist flagellin. Cytokine release was measured by an enzyme immunoassay. ER stress markers CHOP, GRP78 and XBP1s/u were measured via quantitative PCR and Western blot. Monocyte-derived DCs [moDCs] were cultured with the IEC supernatants and their activation state was measured. Responses from enteroids derived from IBD patients and healthy control participants were compared. Results ER stress enhanced flagellin-induced IL-8 release from Caco-2 cells and enteroids. Moreover, conditioned media activated DCs to become pro-inflammatory, with increased expression of CD80, CD86, MHCII, IL-6, IL-15 and IL-12p70 and decreased expression of CD103 and IL-10. Flagellin-induced IL-8 production correlated with DC activation, suggesting a common stress pathway. Moreover, there were distinct differences in cytokine expression and basal ER stress between IBD and healthy subject-derived enteroid monolayers, suggesting a dysregulated ER stress pathway in IBD-derived enteroids. Conclusions Cellular stress enhances TLR5 responses in IECs, leading to increased DC activation, indicating a previously unknown mechanistic link between epithelial ER stress and immune activation in IBD. Furthermore, dysregulated ER stress may be propagated from the intestinal epithelial stem cell niche in IBD patients.

scholarly journals Enhanced endoplasmic reticulum and mitochondrial stress in abdominal aortic aneurysm

2019 ◽  
Vol 133 (13) ◽  
pp. 1421-1438 ◽  
Author(s):  
Miquel Navas-Madroñal ◽  
Cristina Rodriguez ◽  
Modar Kassan ◽  
Joan Fité ◽  
José R. Escudero ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Er Stress ◽  
Mitochondrial Biogenesis ◽  
Atmospheric Pressure Chemical Ionization ◽  
Vascular Wall ◽  
Protein Levels ◽  
Abdominal Aortic ◽  
Healthy Donors

Abstract Abdominal aortic aneurysm (AAA) is a degenerative vascular disease with a complex aetiology that remains to be fully elucidated. Clinical management of AAA is limited to surgical repair, while an effective pharmacotherapy is still awaited. Endoplasmic reticulum (ER) stress and mitochondrial dysfunction have been involved in the pathogenesis of cardiovascular diseases (CVDs), although their contribution to AAA development is uncertain. Therefore, we aimed to determine their implication in AAA and investigated the profile of oxysterols in plasma, specifically 7-ketocholesterol (7-KC), as an ER stress inducer. In the present study, we determined aortic ER stress activation in a large cohort of AAA patients compared with healthy donors. Higher gene expression of activating transcription factor (ATF) 6 (ATF6), IRE-1, X-binding protein 1 (XBP-1), C/EBP-homologous protein (CHOP), CRELD2 and suppressor/enhancer of Lin-12-like (SEL1L) and greater protein levels of active ATF6, active XBP1 and of the pro-apoptotic protein CHOP were detected in human aneurysmatic samples. This was accompanied by an exacerbated apoptosis, higher reactive oxygen species (ROS) production and by a reduction in mitochondrial biogenesis in the vascular wall of AAA. The quantification of oxysterols, performed by liquid chromatography-(atmospheric pressure chemical ionization (APCI))-mass spectrometry, showed that levels of 7-KC were significantly higher while those of 7α-hydroxycholesterol (HC), 24-HC and 27-HC were lower in AAA patients compared with healthy donors. Interestingly, the levels of 7-KC correlate with the expression of ER stress markers. Our results evidence an induction of ER stress in the vascular wall of AAA patients associated with an increase in circulating 7-KC levels and a reduction in mitochondrial biogenesis suggesting their implication in the pathophysiology of this disease.

scholarly journals Novel effects of the cyclooxygenase-2-selective inhibitor NS-398 on IL-1β-induced cyclooxygenase-2 and IL-8 expression in human ovarian granulosa cells

2016 ◽  
Vol 22 (6) ◽  
pp. 452-465 ◽  
Author(s):  
Hui-Ling Ou ◽  
David Sun ◽  
Yen-Chun Peng ◽  
Yuh-Lin Wu
Keyword(s):  
Inflammatory Response ◽  
Granulosa Cells ◽  
Cell Cycle Progression ◽  
Nuclear Translocation ◽  
Selective Inhibitor ◽  
Cyclooxygenase 2 ◽  
Cycle Progression ◽  
Ovarian Granulosa Cell ◽  
Cox 2 ◽  
The Impact

Ovulation is a critical inflammation-like event that is central to ovarian physiology. IL-1β is an immediate early pro-inflammatory cytokine that regulates production of several other inflammatory mediators, such as cyclooxygenase 2 (COX)-2 and IL-8. NS-398 is a selective inhibitor of COX-2 bioactivity and thus this drug is able to mitigate the COX-2-mediated production of downstream prostaglandins and the subsequent inflammatory response. Here we have investigated the action of NS-398 using a human ovarian granulosa cell line, KGN, by exploring IL-1β-regulated COX-2 and IL-8 expression. First, NS-398, instead of reducing inflammation, appeared to further enhance IL-1β-mediated COX-2 and IL-8 production. Using selective inhibitors targeting various signaling molecules, MAPK and NF-κB pathways both seemed to be involved in the impact of NS-398 on IL-1β-induced COX-2 and IL-8 expression. NS-398 also promoted IL-1β-mediated NF-κB p65 nuclear translocation but had no effect on IL-1β-activated MAPK phosphorylation. Flow cytometry analysis demonstrated that NS-398, in combination with IL-1β, significantly enhanced cell cycle progression involving IL-8. Our findings demonstrate a clear pro-inflammatory function for NS-398 in the IL-1β-mediated inflammatory response of granulosa cells, at least in part, owing to its augmenting effect on the IL-1β-induced activation of NF-κB.

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