14,15-Epoxyeicosatrienoic Acid Suppresses Cigarette Smoke Extract-Induced Apoptosis in Lung Epithelial Cells by Inhibiting Endoplasmic Reticulum Stress

Background/Aims: Epoxyeicosatrienoic acids (EETs), a type of lipid mediators produced by cytochrome P450 epoxygenases, exert anti-inflammatory, angiogenic, anti-oxidative and anti-apoptotic effects. However, the role of EETs in cigarette smoke-induced lung injury and the underlying mechanisms are not fully known. The aim of this study was to explore the effects of CYP2J2-EETs on cigarette smoke extracts (CSE)-induced apoptosis in human bronchial epithelial cell line (Beas-2B) and the possible mechanisms involved. Methods: Cytochrome P450 epoxygenase 2J2 (CYP2J2) and its metabolites EETs were assessed by western blotting or LC-MS-MS. Cell viability and apoptosis were determined by MTT assay and AnnexinV-PI staining. Reactive oxygen species (ROS) were assessed by measuring H2DCFDA. Caspase-3, HO-1, MAPK and endoplasmic reticulum (ER) stress-related markers GRP78, p-elF2a, and CHOP were evaluated by western blotting. Results: CSE suppressed expression of both CYP2J2 and EET by Beas-2B cells. CSE also induced apoptosis, the generation of ROS and the ER stress in Beas-2B cells. These changes were abolished by pretreatment with exogenous 14,15-EET while pretreatment with 14,15-EEZE, a selective EET antagonist, abolished the protective effects of 14,15-EET. In addition, EETs increased the expression of antioxidant enzyme HO-1. Furthermore, 14,15-EET reduced CSE-induced activation of p38 and JNK. Conclusion: The data suggest that CYP2J2-derived EETs protect against CSE-induced lung injury possibly through attenuating ER stress.

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Suppression of Endoplasmic Reticulum Stress by 4-PBA Protects Against Hyperoxia-Induced Acute Lung Injury via Up-Regulating Claudin-4 Expression

Frontiers in Immunology ◽

10.3389/fimmu.2021.674316 ◽

2021 ◽

Vol 12 ◽

Author(s):

Hsin-Ping Pao ◽

Wen-I. Liao ◽

Shih-En Tang ◽

Shu-Yu Wu ◽

Kun-Lun Huang ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Acute Lung Injury ◽

Lung Injury ◽

Protein Expression ◽

Er Stress ◽

Lung Tissue ◽

Lung Epithelial Cells ◽

Stress Factors ◽

Mouse Lung ◽

Lung Edema

Endoplasmic reticulum (ER) stress that disrupts ER function can occur in response to a wide variety of cellular stress factors leads to the accumulation of unfolded and misfolded proteins in the ER. Many studies have shown that ER stress amplified inflammatory reactions and was involved in various inflammatory diseases. However, little is known regarding the role of ER stress in hyperoxia-induced acute lung injury (HALI). This study investigated the influence of ER stress inhibitor, 4-phenyl butyric acid (4-PBA), in mice with HALI. Treatment with 4-PBA in the hyperoxia groups significantly prolonged the survival, decreased lung edema, and reduced the levels of inflammatory mediators, lactate dehydrogenase, and protein in bronchoalveolar lavage fluid, and increased claudin-4 protein expression in lung tissue. Moreover, 4-PBA reduced the ER stress-related protein expression, NF-κB activation, and apoptosis in the lung tissue. In in vitro study, 4-PBA also exerted a similar effect in hyperoxia-exposed mouse lung epithelial cells (MLE-12). However, when claudin-4 siRNA was administrated in mice and MLE-12 cells, the protective effect of 4-PBA was abrogated. These results suggested that 4-PBA protected against hyperoxia-induced ALI via enhancing claudin-4 expression.

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5-ALA Attenuates the Palmitic Acid-Induced ER Stress and Apoptosis in Bovine Mammary Epithelial Cells

Molecules ◽

10.3390/molecules26041183 ◽

2021 ◽

Vol 26 (4) ◽

pp. 1183

Author(s):

Mst Mamuna Sharmin ◽

Md Aminul Islam ◽

Itsuki Yamamoto ◽

Shin Taniguchi ◽

Shinichi Yonekura

Keyword(s):

T Cells ◽

Epithelial Cells ◽

Palmitic Acid ◽

Er Stress ◽

Aminolevulinic Acid ◽

Mammary Epithelial Cells ◽

Mammary Epithelial ◽

Protective Effects ◽

Bovine Mammary Epithelial Cells ◽

Induced Apoptosis

The conservation of mammary gland physiology by maintaining the maximum number of mammary epithelial cells (MECs) is of the utmost importance for the optimum amount of milk production. In a state of negative energy balance, palmitic acid (PA) reduces the number of bovine MECs. However, there is no effective strategy against PA-induced apoptosis of MECs. In the present study, 5-aminolevulinic acid (5-ALA) was established as a remedial agent against PA-induced apoptosis of MAC-T cells (an established line of bovine MECs). In PA-treated cells, the apoptosis-related genes BCL2 and BAX were down- and upregulated, respectively. The elevated expression of major genes of the unfolded protein response (UPR), such as CHOP, a proapoptotic marker (C/EBP homologous protein), reduced the viability of PA-treated MAC-T cells. In contrast, 5-ALA pretreatment increased and decreased BCL2 and BAX expression, respectively. Moreover, cleaved caspase-3 protein expression was significantly reduced in the 5-ALA-pretreated group in comparison with the PA group. The downregulation of major UPR-related genes, including CHOP, extended the viability of MAC-T cells pretreated with 5-ALA and also reduced the enhanced intensity of the PA-induced expression of phospho-protein kinase R-like ER kinase. Moreover, the enhanced expression of HO-1 (antioxidant gene heme oxygenase) by 5-ALA reduced PA-induced oxidative stress (OxS). HO-1 is not only protective against OxS but also effective against ER stress. Collectively, these findings offer new insights into the protective effects of 5-ALA against PA-induced apoptosis of bovine MECs.

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Characterization of Endoplasmic Reticulum (ER) in Human Pluripotent Stem Cells Revealed Increased Susceptibility to Cell Death upon ER Stress

Cells ◽

10.3390/cells9051078 ◽

2020 ◽

Vol 9 (5) ◽

pp. 1078

Author(s):

Tae Won Ha ◽

Ji Hun Jeong ◽

HyeonSeok Shin ◽

Hyun Kyu Kim ◽

Jeong Suk Im ◽

...

Keyword(s):

Stem Cells ◽

Endoplasmic Reticulum ◽

Er Stress ◽

Pluripotent Stem Cells ◽

Meta Analysis ◽

Embryonic Stem ◽

Structural Features ◽

Human Pluripotent Stem Cells ◽

Differentiated Cells ◽

Induced Apoptosis

Human pluripotent stem cells (hPSCs), such as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), have a well-orchestrated program for differentiation and self-renewal. However, the structural features of unique proteostatic-maintaining mechanisms in hPSCs and their features, distinct from those of differentiated cells, in response to cellular stress remain unclear. We evaluated and compared the morphological features and stress response of hPSCs and fibroblasts. Compared to fibroblasts, electron microscopy showed simpler/fewer structures with fewer networks in the endoplasmic reticulum (ER) of hPSCs, as well as lower expression of ER-related genes according to meta-analysis. As hPSCs contain low levels of binding immunoglobulin protein (BiP), an ER chaperone, thapsigargin treatment sharply increased the gene expression of the unfolded protein response. Thus, hPSCs with decreased chaperone function reacted sensitively to ER stress and entered apoptosis faster than fibroblasts. Such ER stress-induced apoptotic processes were abolished by tauroursodeoxycholic acid, an ER-stress reliever. Hence, our results revealed that as PSCs have an underdeveloped structure and express fewer BiP chaperone proteins than somatic cells, they are more susceptible to ER stress-induced apoptosis in response to stress.

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Attenuation of endoplasmic reticulum stress by caffeine ameliorates hyperoxia-induced lung injury

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00405.2016 ◽

2017 ◽

Vol 312 (5) ◽

pp. L586-L598 ◽

Cited By ~ 38

Author(s):

Ru-Jeng Teng ◽

Xigang Jing ◽

Teresa Michalkiewicz ◽

Adeleye J. Afolayan ◽

Tzong-Jin Wu ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Lung Injury ◽

Er Stress ◽

Saline Control ◽

Sprague Dawley ◽

Chemical Chaperone ◽

Stress Markers ◽

Rat Pups ◽

Caffeine Treatment ◽

Downstream Effectors

Rodent pups exposed to hyperoxia develop lung changes similar to bronchopulmonary dysplasia (BPD) in extremely premature infants. Oxidative stress from hyperoxia can injure developing lungs through endoplasmic reticulum (ER) stress. Early caffeine treatment decreases the rate of BPD, but the mechanisms remain unclear. We hypothesized that caffeine attenuates hyperoxia-induced lung injury through its chemical chaperone property. Sprague-Dawley rat pups were raised either in 90 (hyperoxia) or 21% (normoxia) oxygen from postnatal day 1 (P1) to postnatal day 10 (P10) and then recovered in 21% oxygen until P21. Caffeine (20 mg/kg) or normal saline (control) was administered intraperitoneally daily starting from P2. Lungs were inflation-fixed for histology or snap-frozen for immunoblots. Blood caffeine levels were measured in treated pups at euthanasia and were found to be 18.4 ± 4.9 μg/ml. Hyperoxia impaired alveolar formation and increased ER stress markers and downstream effectors; caffeine treatment attenuated these changes at P10. Caffeine also attenuated the hyperoxia-induced activation of cyclooxygenase-2 and markers of apoptosis. In conclusion, hyperoxia-induced alveolar growth impairment is mediated, in part, by ER stress. Early caffeine treatment protects developing lungs from hyperoxia-induced injury by attenuating ER stress.

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

International Journal of Molecular Sciences ◽

10.3390/ijms222010951 ◽

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.

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Abstract 590: Increased Endoplasmic Reticulum Stress in Atherosclerotic Plaques Associated With Acute Coronary Syndrome

Circulation ◽

10.1161/circ.116.suppl_16.ii_107-a ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Masafumi Myoishi ◽

Testuo Minamino ◽

Masafumi Kitakaze

Keyword(s):

Endoplasmic Reticulum ◽

Coronary Artery ◽

Er Stress ◽

Atherosclerotic Plaques ◽

Coronary Syndrome ◽

Er Chaperone ◽

Unstable Plaques ◽

Induced Apoptosis ◽

Stress Dependent ◽

Dependent Pathway

Background Endoplasmic reticulum (ER) responds to various stresses by up-regulation of ER chaperones, and prolonged ER stress eventually causes apoptosis. Although apoptosis is considered to be essential for the progression and rupture of atherosclerotic plaques, the influence of ER stress and apoptosis on rupture of unstable coronary plaques remains unclear. Methods and Results We obtained 152 coronary artery segments at autopsy and 40 atherectomy specimens from 71 and 40 patients, respectively . Smooth muscle cells (SMCs) and macrophages in the fibrous caps of thin cap atheroma and ruptured plaques, but not in the fibrous caps of thick cap atheroma and fibrous plaques, showed a marked increase in the expression of ER chaperone and numbers of apoptotic cells. ER chaperones also expressed higher in atherectomy specimens from patients with unstable angina pectoris than with stable angina. To explore the plausible molecular mechanism of activation of ER stress and the mechanistic link to apoptosis, we investigated plaque lipids such as oxysterols. Among oxysterols, expression of 7-ketocholesterol was increased in the fibrous caps of thin cap atheroma compared with thick cap atheroma. Treatment of either cultured coronary artery SMCs or THP-1 cells with 7-ketocholesterol induced upregulation of ER chaperones and apoptosis, while these changes were prevented by antioxidants. We also investigated possible signaling pathways for ER-initiated apoptosis and found that the CHOP (a transcription factor induced by ER stress)-dependent pathway was activated in unstable plaques. In addition, knockdown of CHOP expression by siRNA decreased ER stress-dependent death of cultured coronary artery SMCs and THP-1 cells. Conclusions Increased ER stress occurs in unstable plaques. Our findings suggest that ER stress-induced apoptosis of SMCs and macrophages may contribute to plaque vulnerability.

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Protective effects of hydrogen against irradiation

Current Pharmaceutical Design ◽

10.2174/1381612827666210119103545 ◽

2021 ◽

Vol 27 ◽

Author(s):

Yasuhiro Terasaki ◽

Mika Terasaki ◽

Akira Shimizu

Keyword(s):

Oxidative Stress ◽

Lung Injury ◽

Cultured Cells ◽

Animal Experiments ◽

Lung Epithelial Cells ◽

Lung Damage ◽

Protective Effects ◽

Chronic Radiation ◽

Radiation Induced ◽

Reactive Oxidants

: Radiation-induced lung injury is characterized by an acute pneumonia phase followed by a fibrotic phase. At the time of irradiation, a rapid, short-lived burst of reactive oxygen species (ROS) such as hydroxyl radicals (•OH) occurs, but chronic radiation-induced lung injury may occur due to excess ROS such as H2O2 , O2•− , ONOO− , and •OH. Molecular hydrogen (H2 ) is an efficient antioxidant that quickly diffuses cell membranes, reduces ROS such as •OH and ONOO− , and suppresses damage caused by oxidative stress in various organs. In 2011, through the evaluation of electron-spin resonance and fluorescent indicator signals, we had reported that H2 can eliminate •OH and can protect against oxidative stress-related apoptotic damage induced by irradiation of cultured lung epithelial cells. We had explored for the first time the radioprotective effects of H2 treatment on acute and chronic radiation-induced lung damage in mice by inhaled H2 gas (for acute) and imbibed H2 -enriched water (for chronic). Thus, we had proposed that H2 be considered a potential radioprotective agent. Recent publications have shown that H2 directly neutralizes highly reactive oxidants and indirectly reduces oxidative stress by regulating the expression of various genes. By regulating gene expression, H2 functions as an anti-inflammatory and anti-apoptotic molecule and promotes energy metabolism. The increased evidence obtained from cultured cells or animal experiments reveal a putative place for H2 treatment and its radioprotective effect clinically. This review focuses on major scientific advances of in the treatment of H2 as a new class of radioprotective agents.

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Japanese Encephalitis Virus Induces Apoptosis and Encephalitis by Activating the PERK Pathway

Journal of Virology ◽

10.1128/jvi.00887-19 ◽

2019 ◽

Vol 93 (17) ◽

Cited By ~ 6

Author(s):

Qianruo Wang ◽

Xiu Xin ◽

Ting Wang ◽

Jiawu Wan ◽

Yangtao Ou ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Er Stress ◽

Japanese Encephalitis Virus ◽

Japanese Encephalitis ◽

Encephalitis Virus ◽

Protein Kinase R ◽

Apoptosis Pathway ◽

Stress Sensor ◽

Sensor Protein ◽

Induced Apoptosis

ABSTRACTAccumulated evidence demonstrates that Japanese encephalitis virus (JEV) infection triggers endoplasmic reticulum (ER) stress and neuron apoptosis. ER stress sensor protein kinase R-like endoplasmic reticulum kinase (PERK) has been reported to induce apoptosis under acute or prolonged ER stress. However, the precise role of PERK in JEV-induced apoptosis and encephalitis remains unknown. Here, we report that JEV infection activates the PERK-ATF4-CHOP apoptosis pathway bothin vitroandin vivo. PERK activation also promotes the formation of stress granule, which in turn represses JEV-induced apoptosis. However, PERK inhibitor reduces apoptosis, indicating that JEV-activated PERK predominantly induces apoptosis via the PERK-ATF4-CHOP apoptosis pathway. Among JEV proteins that have been reported to induce ER stress, only JEV NS4B can induce PERK activation. PERK has been reported to form an active molecule by dimerization. The coimmunoprecipitation assay shows that NS4B interacts with PERK. Moreover, glycerol gradient centrifugation shows that NS4B induces PERK dimerization. Both the LIG-FHA and the LIG-WD40 domains within NS4B are required to induce PERK dimerization, suggesting that JEV NS4B pulls two PERK molecules together by simultaneously interacting with them via different motifs. PERK deactivation reduces brain cell damage and encephalitis during JEV infection. Furthermore, expression of JEV NS4B is sufficient to induce encephalitis via PERK in mice, indicating that JEV activates PERK primarily via its NS4B to cause encephalitis. Taken together, our findings provide a novel insight into JEV-caused encephalitis.IMPORTANCEJapanese encephalitis virus (JEV) infection triggers endoplasmic reticulum (ER) stress and neuron apoptosis. ER stress sensor protein kinase R-like endoplasmic reticulum kinase (PERK) has been reported to induce apoptosis under acute or prolonged ER stress. However, whether the PERK pathway of ER stress response plays important roles in JEV-induced apoptosis and encephalitis remains unknown. Here, we found that JEV infection activates ER stress sensor PERK in neuronal cells and mouse brains. PERK activation induces apoptosis via the PERK-ATF4-CHOP apoptosis pathway upon JEV infection. Among the JEV proteins prM, E, NS1, NS2A, NS2B, and NS4B, only NS4B activates PERK. Moreover, activated PERK participates in apoptosis and encephalitis induced by JEV and NS4B. These findings provide a novel therapeutic approach for JEV-caused encephalitis.

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