Endoplasmic Reticulum (ER) Stress and Endocrine Disorders

PubMed Central

Ariyasu, Daisuke; Yoshida, Hiderou; Hasegawa, Yukihiro

2017-01-01

The endoplasmic reticulum (ER) is the organelle where secretory and membrane proteins are synthesized and folded. Unfolded proteins that are retained within the ER can cause ER stress. Eukaryotic cells have a defense system called the “unfolded protein response” (UPR), which protects cells from ER stress. Cells undergo apoptosis when ER stress exceeds the capacity of the UPR, which has been revealed to cause human diseases. Although neurodegenerative diseases are well-known ER stress-related diseases, it has been discovered that endocrine diseases are also related to ER stress. In this review, we focus on ER stress-related human endocrine disorders. In addition to diabetes mellitus, which is well characterized, several relatively rare genetic disorders such as familial neurohypophyseal diabetes insipidus (FNDI), Wolfram syndrome, and isolated growth hormone deficiency type II (IGHD2) are discussed in this article. PMID:28208663

ER Stress: A Therapeutic Target in Rheumatoid Arthritis?

PubMed

Rahmati, Marveh; Moosavi, Mohammad Amin; McDermott, Michael F

2018-04-22

Diverse physiological and pathological conditions that impact on protein folding of the endoplasmic reticulum (ER) cause ER stress. The unfolded protein response (UPR) and the ER-associated degradation (ERAD) pathway are activated to cope with ER stress. In rheumatoid arthritis (RA), inflammation and ER stress work in parallel by driving inflammatory cells to release cytokines that induce chronic ER stress pathways. This chronic ER stress may contribute to the pathogenesis of RA through synoviocyte proliferation and proinflammatory cytokine production. Therefore, ER stress pathways and their constituent elements are attractive targets for RA drug development. In this review, we integrate current knowledge of the contribution of ER stress to the overall pathogenesis of RA, and suggest some therapeutic implications of these discoveries. Copyright © 2018 Elsevier Ltd. All rights reserved.

Endoplasmic reticulum: ER stress regulates mitochondrial bioenergetics

PubMed Central

Bravo, Roberto; Gutierrez, Tomás; Paredes, Felipe; Gatica, Damián; Rodriguez, Andrea E.; Pedrozo, Zully; Chiong, Mario; Parra, Valentina; Quest, Andrew F.G.; Rothermel, Beverly A.; Lavandero, Sergio

2014-01-01

Endoplasmic reticulum (ER) stress activates an adaptive unfolded protein response (UPR) that facilitates cellular repair, however, under prolonged ER stress, the UPR can ultimately trigger apoptosis thereby terminating damaged cells. The molecular mechanisms responsible for execution of the cell death program are relatively well characterized, but the metabolic events taking place during the adaptive phase of ER stress remain largely undefined. Here we discuss emerging evidence regarding the metabolic changes that occur during the onset of ER stress and how ER influences mitochondrial function through mechanisms involving calcium transfer, thereby facilitating cellular adaptation. Finally, we highlight how dysregulation of ER–mitochondrial calcium homeostasis during prolonged ER stress is emerging as a novel mechanism implicated in the onset of metabolic disorders. PMID:22064245

Molecular mechanism of ER stress-induced pre-emptive quality control involving association of the translocon, Derlin-1, and HRD1.

PubMed

Kadowaki, Hisae; Satrimafitrah, Pasjan; Takami, Yasunari; Nishitoh, Hideki

2018-05-09

The maintenance of endoplasmic reticulum (ER) homeostasis is essential for cell function. ER stress-induced pre-emptive quality control (ERpQC) helps alleviate the burden to a stressed ER by limiting further protein loading. We have previously reported the mechanisms of ERpQC, which includes a rerouting step and a degradation step. Under ER stress conditions, Derlin family proteins (Derlins), which are components of ER-associated degradation, reroute specific ER-targeting proteins to the cytosol. Newly synthesized rerouted polypeptides are degraded via the cytosolic chaperone Bag6 and the AAA-ATPase p97 in the ubiquitin-proteasome system. However, the mechanisms by which ER-targeting proteins are rerouted from the ER translocation pathway to the cytosolic degradation pathway and how the E3 ligase ubiquitinates ERpQC substrates remain unclear. Here, we show that ERpQC substrates are captured by the carboxyl-terminus region of Derlin-1 and ubiquitinated by the HRD1 E3 ubiquitin ligase prior to degradation. Moreover, HRD1 forms a large ERpQC-related complex composed of Sec61α and Derlin-1 during ER stress. These findings indicate that the association of the degradation factor HRD1 with the translocon and the rerouting factor Derlin-1 may be necessary for the smooth and effective clearance of ERpQC substrates.

ER stress and ER stress-induced apoptosis are activated in gastric SMCs in diabetic rats

PubMed Central

Chen, Xia; Fu, Xiang-Sheng; Li, Chang-Ping; Zhao, Hong-Xian

2014-01-01

AIM: To investigate the gastric muscle injury caused by endoplasmic reticulum (ER) stress in rats with diabetic gastroparesis. METHODS: Forty rats were randomly divided into two groups: a control group and a diabetic group. Diabetes was induced by intraperitoneal injection of 60 mg/kg of streptozotocin. Gastric emptying was determined at the 4th and 12th week. The ultrastructural changes in gastric smooth muscle cells (SMCs) were investigated by transmission electron microscopy. TdT-mediated dUTP nick end labeling (TUNEL) assay was performed to assess apoptosis of SMCs. Expression of the ER stress marker, glucose-regulated protein 78 (GRP78), and the ER-specific apoptosis mediator, caspase-12 protein, was determined by immunohistochemistry. RESULTS: Gastric emptying was significantly lower in the diabetic rats than in the control rats at the 12th wk (40.71% ± 2.50%, control rats vs 54.65% ± 5.22%, diabetic rats; P < 0.05). Swollen and distended ER with an irregular shape was observed in gastric SMCs in diabetic rats. Apoptosis of gastric SMCs increased in the diabetic rats in addition to increased expression of GRP78 and caspase-12 proteins. CONCLUSION: ER stress and ER stress-mediated apoptosis are activated in gastric SMCs in diabetic rats with gastroparesis. PMID:25009401

ER stress-induced protein, VIGG, disturbs plant cation homeostasis, which is correlated with growth retardation and robustness to ER stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katoh, Hironori; Fujita, Keiko; Takuhara, Yuki

2011-02-18

Highlights: {yields} VIGG is an ER stress-induced protein in plant. {yields} We examine the characteristics of VIGG-overexpressing Arabidopsis plants. {yields} VIGG-overexpressing plants reveal growth retardation and robustness to ER stress. {yields} VIGG disturbs cation homeostasis in plant. -- Abstract: VIGG is a putative endoplasmic reticulum (ER) resident protein induced by virus infection and ER stress, and is correlated with fruit quality in grapevine. The present study was undertaken to determine the biological function of VIGG in grapevine. Experiments using fluorescent protein-VIGG fusion protein demonstrated that VIGG is localized in ER and the ER targeting sequence is in the N-terminus. Themore » overexpression of VIGG in Arabidopsis plant led to growth retardation. The rosette leaves of VIGG-overexpressing plants were smaller than those of the control plants and rolled at 42 days after seeding. VIGG-overexpressing plants revealed robustness to ER stress as well as the low expression of ER stress marker proteins, such as the luminal binding proteins. These characteristics of VIGG-overexpressing plants were supported by a microarray experiment that demonstrated the disruption of genes related to ER stress response and flowering, as well as cation mobility, in the plants. Finally, cation homeostasis in the plants was disturbed by the overexpression of VIGG. Taken together, these results suggest that VIGG may disturb cation homeostasis in plant, which is correlated with the robustness to ER stress and growth retardation.« less

Alleviating Stress for Women Administrators.

ERIC Educational Resources Information Center

Ten Elshof, Annette; Tomlinson, Elaine

1981-01-01

Describes a workshop designed to help women administrators assess individual stress levels. Stress can be alleviated through exercise, support groups or networking, sleep and diet, relaxation, guided fantasy, and planned activity. The long-term implications include preventing illness and making women more effective within the administrative…

Bicyclol attenuates tetracycline-induced fatty liver associated with inhibition of hepatic ER stress and apoptosis in mice.

PubMed

Yao, Xiao-Min; Li, Yue; Li, Hong-Wei; Cheng, Xiao-Yan; Lin, Ai-Bin; Qu, Jun-Ge

2016-01-01

Endoplasmic reticulum (ER) stress is known to be involved in the development of several metabolic disorders, including non-alcoholic fatty liver disease (NAFLD). Tetracycline can cause hepatic steatosis, and ER stress may be involved in tetracycline-induced fatty liver. Our previous study showed that bicyclol has been proven to protect against tetracycline-induced fatty liver in mice, and ER stress may also be involved in bicyclol's hepatoprotective effect. Therefore, this study was performed to investigate the underlying mechanisms associated with ER stress and apoptosis, by which bicyclol attenuated tetracycline-induced fatty liver in mice. Bicyclol (300 mg/kg) was given to mice by gavage 3 times. Tetracycline (200 mg/kg, intraperitoneally) was injected at 1 h after the last dose of bicyclol. At 6 h and 24 h after single dose of tetracycline injection, serum ALT, AST, TG, CHO and hepatic histopathological examinations were performed to evaluate liver injuries. Hepatic steatosis was assessed by the accumulation of hepatic TG and CHO. Moreover, hepatic apoptosis and ER stress related markers were determined by TUNEL, real-time PCR, and western blot. As a result, bicyclol significantly protected against tetracycline-induced fatty liver as evidenced by the decrease of elevated serum transaminases and hepatic triglyceride, and the attenuation of histopathological changes in mice. In addition, bicyclol remarkably alleviated hepatic apoptosis and the gene expression of caspase-3, and increased the gene expression of XIAP. The gene expressions of ER stress-related markers, including CHOP, GRP78, IRE-1α, and ATF6, which were downregulated by bicyclol pretreatment in tetracycline-injected mice. These results suggested that bicyclol protected tetracycline-induced fatty liver partly due to its ability of anti-apoptosis associated with ER stress.

Dietary toxins, endoplasmic reticulum (ER) stress and diabetes.

PubMed

Hettiarachchi, Kalindi D; Zimmet, Paul Z; Myers, Mark A

2008-05-01

The incidence of Type 1 diabetes has been increasing at a rate too rapid to be due to changes in genetic risk. Instead changes in environmental factors are the likely culprit. The endoplasmic reticulum (ER) plays an important role in the production of newly synthesized proteins and interference with these processes leads to ER stress. The insulin-producing beta cells are particularly prone to ER stress as a result of their heavy engagement in insulin production. Increasing evidence suggests ER stress is central to initiation and progression of Type 1 diabetes. An early environmental exposure, such as toxins and viral infections, can impart a significant physiological load on beta cells to initiate abnormal processing of proinsulin, ER stress and insulin secretory defects. Release of altered proinsulin from the beta cells early in life may trigger autoimmunity in those with genetic susceptibility leading to cytokine-induced nitric oxide production and so exacerbating ER stress in beta cells, ultimately leading to apoptosis of beta cells and diabetes. Here we suggest that ER stress is an inherent cause of beta cell dysfunction and environmental factors, in particular dietary toxins derived from Streptomyces in infected root vegetables, can impart additional stress that aggravates beta cell death and progression to diabetes. Furthermore, we propose that the increasing incidence of Type 1 diabetes may be accounted for by increased dietary exposure to ER-stress-inducing Streptomyces toxins.

Oroxin B selectively induces tumor-suppressive ER stress and concurrently inhibits tumor-adaptive ER stress in B-lymphoma cells for effective anti-lymphoma therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Ping; Fu, Shilong; Cao, Zhifei

Cancer cells have both tumor-adaptive and -suppressive endoplasmic reticulum (ER) stress machineries that determine cell fate. In malignant tumors including lymphoma, constant activation of tumor-adaptive ER stress and concurrent reduction of tumor-suppressive ER stress favors cancer cell proliferation and tumor growth. Current ER stress-based anti-tumor drugs typically activate both tumor-adaptive and -suppressive ER stresses, resulting in low anti-cancer efficacy; hence, selective induction of tumor-suppressive ER stress and inhibition of tumor-adaptive ER stress are new strategies for novel anti-cancer drug discovery. Thus far, specific tumor-suppressive ER stress therapeutics have remained absent in clinical settings. In this study, we explored unique tumor-suppressivemore » ER stress agents from the traditional Chinese medicinal herb Oroxylum indicum, and found that a small molecule oroxin B selectively induced tumor-suppressive ER stress in malignant lymphoma cells, but not in normal cells, effectively inhibited lymphoma growth in vivo, and significantly prolonged overall survival of lymphoma-xenografted mice without obvious toxicity. Mechanistic studies have revealed that the expression of key tumor-adaptive ER-stress gene GRP78 was notably suppressed by oroxin B via down-regulation of up-stream key signaling protein ATF6, while tumor-suppressive ER stress master gene DDIT3 was strikingly activated through activating the MKK3-p38 signaling pathway, correcting the imbalance between tumor-suppressive DDIT3 and tumor-adaptive GRP78 in lymphoma. Together, selective induction of unique tumor-suppressive ER stress and concurrent inhibition of tumor-adaptive ER stress in malignant lymphoma are new and feasible approaches for novel anti-lymphoma drug discovery and anti-lymphoma therapy. - Highlights: • Oroxin B selectively induces tumor-suppressive ER stress in B-lymphoma cells. • Oroxin B significantly prolonged overall survival of lymphoma-xenografted mice

Astragaloside-IV Alleviates Heat-Induced Inflammation by Inhibiting Endoplasmic Reticulum Stress and Autophagy.

PubMed

Dong, Zhiwei; Zhou, Jian; Zhang, Ying; Chen, Yajie; Yang, Zichen; Huang, Guangtao; Chen, Yu; Yuan, Zhiqiang; Peng, Yizhi; Cao, Tongtong

2017-01-01

Thermal injury is the main cause of pulmonary disease in stroke after burn and can be life threatening. Heat-induced inflammation is an important factor that triggers a series of induces pathological changes. However, this mechanism underlying heat-induced inflammation in thermal inhalation injury remains unclear. Studies have revealed that astragaloside-IV (AS-IV), a natural compound extracted from Astragalus membranaceus, has protective effects in inflammatory diseases. Here, we investigated whether the protective effects of AS-IV occur because of the suppression of heat-induced endoplasmic reticulum (ER) stress and excessive autophagy Methods: AS-IV was administered to Wistar rats after thermal inhalation injury and 16HBE140-cells were treated with AS-IV. TNF-α, IL-6, and IL-8 levels were determined by ELISA and real-time PCR. ER stress and autophagy were determined by western blot. Autophagic flux was measured by recording the fluorescence emission of the fusion protein mRFP-GFP-LC3 by dynamic live-cell imaging. AS-IV had protective effects against heat-induced reactive oxygen species production and attenuated ER stress. AS IV alleviated heat-induced excessive autophagy in vitro and in vivo. Excessive autophagy was attenuated by the PERK inhibitor GSK2656157 and eIF2α siRNA, suggesting that heat stress-induced autophagy can activate the PERK-eIF2α pathway. Beclin 1 and Atg5 siRNAs inhibited the upregulation of the inflammatory cytokines TNF-α, IL-6, and IL-8 after heat exposure. Thus, AS-IV may attenuate inflammatory responses by disrupting the crosstalk between autophagy and the PERK-eIF2α pathway and may be an ideal agent for treating inflammatory pulmonary diseases. © 2017 The Author(s). Published by S. Karger AG, Basel.

Habitat odor can alleviate innate stress responses in mice.

PubMed

Matsukawa, Mutsumi; Imada, Masato; Aizawa, Shin; Sato, Takaaki

2016-01-15

Predatory odors, which can induce innate fear and stress responses in prey species, are frequently used in the development of animal models for several psychiatric diseases including post-traumatic stress disorder (PTSD) following a life-threatening event. We have previously shown that odors can be divided into at least three types; odors that act as (1) innate stressors, (2) as innate relaxants, or (3) have no innate effects on stress responses. Here, we attempted to verify whether an artificial odor, which had no innate effect on predatory odor-induced stress, could alleviate stress if experienced in early life as a habitat odor. In the current study, we demonstrated that the innate responses were changed to counteract stress following a postnatal experience. Moreover, we suggest that inhibitory circuits involved in stress-related neuronal networks and the concentrations of norepinephrine in the hippocampus may be crucial in alleviating stress induced by the predatory odor. Overall, these findings may be important for understanding the mechanisms involved in differential odor responses and also for the development of pharmacotherapeutic interventions that can alleviate stress in illnesses like PTSD. Copyright © 2015 Elsevier B.V. All rights reserved.

PUMA mediates ER stress-induced apoptosis in portal hypertensive gastropathy

PubMed Central

Tan, S; Wei, X; Song, M; Tao, J; Yang, Y; Khatoon, S; Liu, H; Jiang, J; Wu, B

2014-01-01

Mucosal apoptosis has been demonstrated to be an essential pathological feature in portal hypertensive gastropathy (PHG). p53-upregulated modulator of apoptosis (PUMA) was identified as a BH3-only Bcl-2 family protein that has an essential role in apoptosis induced by a variety of stimuli, including endoplasmic reticulum (ER) stress. However, whether PUMA is involved in mucosal apoptosis in PHG remains unclear, and whether PUMA induces PHG by mediating ER stress remains unknown. The aim of the study is to investigate whether PUMA is involved in PHG by mediating ER stress apoptotic signaling. To identify whether PUMA is involved in PHG by mediating ER stress, gastric mucosal injury and apoptosis were studied in both PHG patients and PHG animal models using PUMA knockout (PUMA-KO) and PUMA wild-type (PUMA-WT) mice. The induction of PUMA expression and ER stress signaling were investigated, and the mechanisms of PUMA-mediated apoptosis were analyzed. GES-1 and SGC7901 cell lines were used to further identify whether PUMA-mediated apoptosis was induced by ER stress in vitro. Epithelial apoptosis and PUMA were markedly induced in the gastric mucosa of PHG patients and mouse PHG models. ER stress had a potent role in the induction of PUMA and apoptosis in PHG models, and the apoptosis was obviously attenuated in PUMA-KO mice. Although the targeted deletion of PUMA did not affect ER stress, mitochondrial apoptotic signaling was downregulated in mice. Meanwhile, PUMA knockdown significantly ameliorated ER stress-induced mitochondria-dependent apoptosis in vitro. These results indicate that PUMA mediates ER stress-induced mucosal epithelial apoptosis through the mitochondrial apoptotic pathway in PHG, and that PUMA is a potentially therapeutic target for PHG. PMID:24625987

Lipid overloading during liver regeneration causes delayed hepatocyte DNA replication by increasing ER stress in mice with simple hepatic steatosis.

PubMed

Hamano, Mina; Ezaki, Hisao; Kiso, Shinichi; Furuta, Kunimaro; Egawa, Mayumi; Kizu, Takashi; Chatani, Norihiro; Kamada, Yoshihiro; Yoshida, Yuichi; Takehara, Tetsuo

2014-02-01

Impaired fatty liver regeneration has already been reported in many genetic modification models. However, in diet-induced simple hepatic steatosis, which showed similar phenotype with clinical pathology, whether liver regeneration is impaired or not remains unclear. In this study, we evaluated liver regeneration in mice with diet-induced simple hepatic steatosis, and focused on excess lipid accumulation occurring during liver regeneration. Mice were fed high fat diet (HFD) or control diet for 9-10 weeks. We analyzed intrahepatic lipid accumulation, DNA replication, and various signaling pathways including cell proliferation and ER stress during liver regeneration after partial hepatectomy. In addition, some of mice were pretreated with tauroursodeoxycholic acid (TUDCA), a chemical chaperone which alleviates ER stress, and then we estimated TUDCA effects on liver regeneration. The peak of hepatocyte BrdU incorporation, the expression of proliferation cell nuclear antigen (PCNA) protein, and the expressions of cell cycle-related genes were observed in delayed time in HFD mice. The expression of phosphorylated Erk1/2 was also delayed in HFD mice. The amounts of liver triglyceride were at least twofold higher in HFD mice at each time point. Intrahepatic palmitic acid was increased especially in HFD mice. ER stress induced during liver regeneration was significantly higher in HFD mice. In HFD mice, pretreatment with TUDCA reduced ER stress and resulted in improvement of delayed liver regeneration. In simple hepatic steatosis, lipid overloading occurring during liver regeneration might be caused ER stress and results in delayed hepatocyte DNA replication.

Initiation and execution of lipotoxic ER stress in pancreatic β-cells

PubMed Central

Cunha, Daniel A.; Hekerman, Paul; Ladrière, Laurence; Bazarra-Castro, Angie; Ortis, Fernanda; Wakeham, Marion C.; Moore, Fabrice; Rasschaert, Joanne; Cardozo, Alessandra K.; Bellomo, Elisa; Overbergh, Lutgart; Mathieu, Chantal; Lupi, Roberto; Hai, Tsonwin; Herchuelz, Andre; Marchetti, Piero; Rutter, Guy A.; Eizirik, Décio L.; Cnop, Miriam

2013-01-01

Summary Free fatty acids (FFA) cause apoptosis of pancreatic β-cells and might contribute to β-cell loss in type 2 diabetes via the induction of endoplasmic reticulum (ER) stress. We studied here the molecular mechanisms implicated in FFA-induced ER stress initiation and apoptosis in INS-1E cells, FACS-purified primary β-cells and human islets exposed to oleate and/or palmitate. Treatment with saturated and/or unsaturated FFA led to differential ER stress signaling. Palmitate induced more apoptosis and markedly activated the IRE1, PERK and ATF6 pathways, owing to a sustained depletion of ER Ca2+ stores, whereas the unsaturated FFA oleate led to milder PERK and IRE1 activation and comparable ATF6 signaling. Non-metabolizable methyl-FFA analogs induced neither ER stress nor β-cell apoptosis. The FFA-induced ER stress response was not modified by high glucose concentrations, suggesting that ER stress in primary β-cells is primarily lipotoxic, and not glucolipotoxic. Palmitate, but not oleate, activated JNK. JNK inhibitors reduced palmitate-mediated AP-1 activation and apoptosis. Blocking the transcription factor CHOP delayed palmitate-induced β-cell apoptosis. In conclusion, saturated FFA induce ER stress via ER Ca2+ depletion. The IRE1 and resulting JNK activation contribute to β-cell apoptosis. PERK activation by palmitate also contributes to β-cell apoptosis via CHOP. PMID:18559892

Interleukin 17A exacerbates ER-stress-mediated inflammation of macrophages following ICH.

PubMed

Yang, Zhao; Liu, Qingjun; Shi, Hui; Jiang, Xuheng; Wang, Song; Lu, Yuanlan; Zhang, Ji; Huang, Xiaofei; Yu, Anyong

2018-05-30

IL-17A contributes to the initiation of inflammation following intracerebral hemorrhage (ICH). Endoplasmic reticulum (ER) stress acts on protein folding and contributes to inflammatory diseases. The role of IL-17A in the regulation of ER stress following ICH has not been well characterized. In this study, macrophages were stimulated with IL-17A, and then, ER stress and downstream pro-inflammatory factors were measured in vitro. In addition, brain edema and brain injury in ICH mice were assessed in vivo. We demonstrated that IL-17A induced ER stress in macrophages and thus promoted inflammation in vitro. Conversely, IL-17A inhibition attenuated ER stress and neuroinflammation. Furthermore, ERK 1/2 and p38 MAPK pathways mediated IL-17A-induced ER stress in macrophages. We also showed that IL-17A inhibition significantly attenuated ER stress and brain injury in ICH mice. In conclusion, our results demonstrate that IL 17A increases ER stress in macrophages and represents a novel mechanism in ICH. Copyright © 2018. Published by Elsevier Ltd.

ER signaling is activated to protect human HaCaT keratinocytes from ER stress induced by environmental doses of UVB

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mera, Kentaro; Kawahara, Ko-ichi; Tada, Ko-ichi

Proteins are folded properly in the endoplasmic reticulum (ER). Various stress such as hypoxia, ischemia and starvation interfere with the ER function, causing ER stress, which is defined by the accumulation of unfolded protein (UP) in the ER. ER stress is prevented by the UP response (UPR) and ER-associated degradation (ERAD). These signaling pathways are activated by three major ER molecules, ATF6, IRE-1 and PERK. Using HaCaT cells, we investigated ER signaling in human keratinocytes irradiated by environmental doses of ultraviolet B (UVB). The expression of Ero1-L{alpha}, an upstream signaling molecule of ER stress, decreased at 1-4 h after 10more » mJ/cm{sup 2} irradiation, indicating that the environmental dose of UVB-induced ER stress in HaCaT cells, without growth retardation. Furthermore, expression of intact ATF6 was decreased and it was translocated to the nuclei. The expression of XBP-1, a downstream molecule of IRE-1, which is an ER chaperone whose expression is regulated by XBP-1, and UP ubiquitination were induced by 10 mJ/cm{sup 2} UVB at 4 h. PERK, which regulates apoptosis, was not phosphorylated. Our results demonstrate that UVB irradiation generates UP in HaCaT cells and that the UPR and ERAD systems are activated to protect cells from UVB-induced ER stress. This is the first report to show ER signaling in UVB-irradiated keratinocytes.« less

Natural products targeting ER stress pathway for the treatment of cardiovascular diseases.

PubMed

Choy, Ker Woon; Murugan, Dharmani; Mustafa, Mohd Rais

2018-04-21

Endoplasmic reticulum (ER) is the main organelle for the synthesis, folding, and processing of secretory and transmembrane proteins. Pathological stimuli including hypoxia, ischaemia, inflammation and oxidative stress interrupt the homeostatic function of ER, leading to accumulation of unfolded proteins, a condition referred to as ER stress. ER stress triggers a complex signalling network referred as the unfolded protein response (UPR). Extensive studies have demonstrated that ER stress plays an important role in the pathogenesis of various cardiovascular diseases such as heart failure, ischemic heart disease and atherosclerosis. The importance of natural products in modern medicine are well recognized and continues to be of interests as a source of novel lead compounds. Natural products targeting components of UPR and reducing ER stress offers an innovative strategic approach to treat cardiovascular diseases. In this review, we discussed several therapeutic interventions using natural products with potential cardiovascular protective properties targeting ER stress signalling pathways. Copyright © 2018 Elsevier Ltd. All rights reserved.

Reduced α-MSH Underlies Hypothalamic ER-Stress-Induced Hepatic Gluconeogenesis.

PubMed

Schneeberger, Marc; Gómez-Valadés, Alicia G; Altirriba, Jordi; Sebastián, David; Ramírez, Sara; Garcia, Ainhoa; Esteban, Yaiza; Drougard, Anne; Ferrés-Coy, Albert; Bortolozzi, Analía; Garcia-Roves, Pablo M; Jones, John G; Manadas, Bruno; Zorzano, Antonio; Gomis, Ramon; Claret, Marc

2015-07-21

Alterations in ER homeostasis have been implicated in the pathophysiology of obesity and type-2 diabetes (T2D). Acute ER stress induction in the hypothalamus produces glucose metabolism perturbations. However, the neurobiological basis linking hypothalamic ER stress with abnormal glucose metabolism remains unknown. Here, we report that genetic and induced models of hypothalamic ER stress are associated with alterations in systemic glucose homeostasis due to increased gluconeogenesis (GNG) independent of body weight changes. Defective alpha melanocyte-stimulating hormone (α-MSH) production underlies this metabolic phenotype, as pharmacological strategies aimed at rescuing hypothalamic α-MSH content reversed this phenotype at metabolic and molecular level. Collectively, our results posit defective α-MSH processing as a fundamental mediator of enhanced GNG in the context of hypothalamic ER stress and establish α-MSH deficiency in proopiomelanocortin (POMC) neurons as a potential contributor to the pathophysiology of T2D. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

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

PubMed

Dejeans, Nicolas; Tajeddine, Nicolas; Beck, Raphaël; Verrax, Julien; Taper, Henryk; Gailly, Philippe; Calderon, Pedro Buc

2010-05-01

Increase in cytosolic calcium concentration ([Ca2+](c)), release of endoplasmic reticulum (ER) calcium ([Ca2+](er)) and ER stress have been proposed to be involved in oxidative toxicity. Nevertheless, their relative involvements in the processes leading to cell death are not well defined. In this study, we investigated whether oxidative stress generated during ascorbate-driven menadione redox cycling (Asc/Men) could trigger these three events, and, if so, whether they contributed to Asc/Men cytoxicity in MCF-7 cells. Using microspectrofluorimetry, we demonstrated that Asc/Men-generated oxidative stress was associated with a slow and moderate increase in [Ca2+](c), largely preceding permeation of propidium iodide, and thus cell death. Asc/Men treatment was shown to partially deplete ER calcium stores after 90 min (decrease by 45% compared to control). This event was associated with ER stress activation, as shown by analysis of eIF2 phosphorylation and expression of the molecular chaperone GRP94. Thapsigargin (TG) was then used to study the effect of complete [Ca2+](er) emptying during the oxidative stress generated by Asc/Men. Surprisingly, the combination of TG and Asc/Men increased ER stress to a level considerably higher than that observed for either treatment alone, suggesting that [Ca2+](er) release alone is not sufficient to explain ER stress activation during oxidative stress. Finally, TG-mediated [Ca2+](er) release largely potentiated ER stress, DNA fragmentation and cell death caused by Asc/Men, supporting a role of ER stress in the process of Asc/Men cytotoxicity. Taken together, our results highlight the involvement of ER stress and [Ca2+](er) decrease in the process of oxidative stress-induced cell death in MCF-7 cells. 2009 Elsevier Inc. All rights reserved.

Overexpressed cyclophilin B suppresses apoptosis associated with ROS and Ca2+ homeostasis after ER stress.

PubMed

Kim, Jinhwan; Choi, Tae Gyu; Ding, Yan; Kim, Yeonghwan; Ha, Kwon Soo; Lee, Kyung Ho; Kang, Insug; Ha, Joohun; Kaufman, Randal J; Lee, Jinhwa; Choe, Wonchae; Kim, Sung Soo

2008-11-01

Prolonged accumulation of misfolded proteins in the endoplasmic reticulum (ER) results in ER stress-mediated apoptosis. Cyclophilins are protein chaperones that accelerate the rate of protein folding through their peptidyl-prolyl cis-trans isomerase (PPIase) activity. In this study, we demonstrated that ER stress activates the expression of the ER-localized cyclophilin B (CypB) gene through a novel ER stress response element. Overexpression of wild-type CypB attenuated ER stress-induced cell death, whereas overexpression of an isomerase activity-defective mutant, CypB/R62A, not only increased Ca(2+) leakage from the ER and ROS generation, but also decreased mitochondrial membrane potential, resulting in cell death following exposure to ER stress-inducing agents. siRNA-mediated inhibition of CypB expression rendered cells more vulnerable to ER stress. Finally, CypB interacted with the ER stress-related chaperones, Bip and Grp94. Taken together, we concluded that CypB performs a crucial function in protecting cells against ER stress via its PPIase activity.

Structural Reorganization of the Vaginal Mucosa in Stress Urinary Incontinence under Conditions of Er:YAG Laser Treatment.

PubMed

Lapii, G A; Yakovleva, A Yu; Neimark, A I

2017-02-01

Structural characteristics of the vaginal mucosa in stress incontinence and its correction by IncontiLase technology were studied. Studies of vaginal biopsy specimens before the exposure showed degenerative and atrophic changes in the stratified squamous epithelium, disorganization of fibrillar structures of the intercellular matrix, and microcirculatory disorders. Studies after Er:YAG laser exposure showed signs of neocollagenogenesis and elastogenesis, foci of neoangiogenesis, reduction of epithelial degeneration and atrophy, and an increase of the fibroblast population. Morphometry showed that the volume density of blood capillaries and the thickness of the epithelial layer increased by 61.1 and 64.5%, respectively. The use of IncontiLase technology in stress incontinence led to structural reorganization of the vaginal mucosa, improving its morphology and function and alleviating the symptoms of incontinence.

Obesity-induced endoplasmic reticulum stress suppresses nuclear factor-Y expression.

PubMed

Liu, Yulan; Zhang, Yuwei; Zhang, Yanjie; Zhang, Jinlong; Liu, Yin; Feng, Peiqun; Su, Zhiguang

2017-02-01

Nuclear transcription factor Y (NF-Y) is an evolutionarily conserved transcription factor composed of three subunits, NF-YA, NF-YB, and NF-YC. NF-Y plays crucial roles in pre-adipocyte maintenance and/or commitment to adipogenesis. NF-YA dysfunction in adipocyte resulted in an age-dependent progressive loss of adipose tissue associated with metabolic complications. Endoplasmic reticulum (ER) stress has emerged as an important mediator in the pathogenesis of obesity. However, it is not known if NF-YA is involved in the ER stress-mediated pathogenesis of obesity. We first examined the effects of ER stress on the NF-YA expression in cultured 3T3-L1 adipocytes; then in ob/ob genetic obesity mice, we tested the effect of chemical chaperones alleviating ER stress on the expression levels of NF-YA. Subsequently, we inhibited the new mRNA synthesis using actinomycin D in 3T3-L1 cells to explore the mechanism modulating NF-YA expression. Finally, we evaluated the involvement of PPARg in the regulation of NF-YA expression by ER stress. We demonstrated that both obesity- and chemical chaperone -induced ER stress suppressed NF-YA expression and alleviation of ER stress by chemical chaperone could recover NF-YA expression in ob/ob mice. Moreover, we showed that ER stress suppressed NF-YA mRNA transcription through the involvement of peroxisome proliferator-activated receptor gamma (PPARg). Activation of PPARg ameliorates the ER stress-induced NF-YA suppression. Our findings may point to a possible role of NF-YA in stress conditions that occur in chronic obesity, ER stress might be involved in the pathogenesis of obesity through NF-YA depletion.

Ocular-specific ER stress reduction rescues glaucoma in murine glucocorticoid-induced glaucoma

PubMed Central

Zode, Gulab S.; Sharma, Arti B.; Lin, Xiaolei; Searby, Charles C.; Bugge, Kevin; Kim, Gun Hee; Clark, Abbot F.; Sheffield, Val C.

2014-01-01

Administration of glucocorticoids induces ocular hypertension in some patients. If untreated, these patients can develop a secondary glaucoma that resembles primary open-angle glaucoma (POAG). The underlying pathology of glucocorticoid-induced glaucoma is not fully understood, due in part to lack of an appropriate animal model. Here, we developed a murine model of glucocorticoid-induced glaucoma that exhibits glaucoma features that are observed in patients. Treatment of WT mice with topical ocular 0.1% dexamethasone led to elevation of intraocular pressure (IOP), functional and structural loss of retinal ganglion cells, and axonal degeneration, resembling glucocorticoid-induced glaucoma in human patients. Furthermore, dexamethasone-induced ocular hypertension was associated with chronic ER stress of the trabecular meshwork (TM). Similar to patients, withdrawal of dexamethasone treatment reduced elevated IOP and ER stress in this animal model. Dexamethasone induced the transcriptional factor CHOP, a marker for chronic ER stress, in the anterior segment tissues, and Chop deletion reduced ER stress in these tissues and prevented dexamethasone-induced ocular hypertension. Furthermore, reduction of ER stress in the TM with sodium 4-phenylbutyrate prevented dexamethasone-induced ocular hypertension in WT mice. Our data indicate that ER stress contributes to glucocorticoid-induced ocular hypertension and suggest that reducing ER stress has potential as a therapeutic strategy for treating glucocorticoid-induced glaucoma. PMID:24691439

Thiamine deficiency induces endoplasmic reticulum stress and oxidative stress in human neurons derived from induced pluripotent stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Xin; Xu, Mei; Frank, Jacqueline A.

Thiamine (vitamin B1) deficiency (TD) plays a major role in the etiology of Wernicke's encephalopathy (WE) which is a severe neurological disorder. TD induces selective neuronal cell death, neuroinflammation, endoplasmic reticulum (ER) stress and oxidative stress in the brain which are commonly observed in many aging-related neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD) and progressive supranuclear palsy (PSP). However, the underlying cellular and molecular mechanisms remain unclear. The progress in this line of research is hindered due to the lack of appropriate in vitro models. The neurons derived for the human induced pluripotent stemmore » cells (hiPSCs) provide a relevant and powerful tool for the research in pharmaceutical and environmental neurotoxicity. In this study, we for the first time used human induced pluripotent stem cells (hiPSCs)-derived neurons (iCell neurons) to investigate the mechanisms of TD-induced neurodegeneration. We showed that TD caused a concentration- and duration-dependent death of iCell neurons. TD induced ER stress which was evident by the increase in ER stress markers, such as GRP78, XBP-1, CHOP, ATF-6, phosphorylated eIF2α, and cleaved caspase-12. TD also triggered oxidative stress which was shown by the increase in the expression 2,4-dinitrophenyl (DNP) and 4-hydroxynonenal (HNE). ER stress inhibitors (STF-083010 and salubrinal) and antioxidant N-acetyl cysteine (NAC) were effective in alleviating TD-induced death of iCell neurons, supporting the involvement of ER stress and oxidative stress. It establishes that the iCell neurons are a novel tool to investigate cellular and molecular mechanisms for TD-induced neurodegeneration. - Highlights: • Thiamine deficiency (TD) causes death of human neurons in culture. • TD induces both endoplasmic reticulum (ER) stress and oxidative stress. • Alleviating ER stress and oxidative stress reduces TD

Arbuscular mycorrhizal fungi in alleviation of salt stress: a review

PubMed Central

Evelin, Heikham; Kapoor, Rupam; Giri, Bhoopander

2009-01-01

Background Salt stress has become a major threat to plant growth and productivity. Arbuscular mycorrhizal fungi colonize plant root systems and modulate plant growth in various ways. Scope This review addresses the significance of arbuscular mycorrhiza in alleviation of salt stress and their beneficial effects on plant growth and productivity. It also focuses on recent progress in unravelling biochemical, physiological and molecular mechanisms in mycorrhizal plants to alleviate salt stress. Conclusions The role of arbuscular mycorrhizal fungi in alleviating salt stress is well documented. This paper reviews the mechanisms arbuscular mycorrhizal fungi employ to enhance the salt tolerance of host plants such as enhanced nutrient acquisition (P, N, Mg and Ca), maintenance of the K+ : Na+ ratio, biochemical changes (accumulation of proline, betaines, polyamines, carbohydrates and antioxidants), physiological changes (photosynthetic efficiency, relative permeability, water status, abscissic acid accumulation, nodulation and nitrogen fixation), molecular changes (the expression of genes: PIP, Na+/H+ antiporters, Lsnced, Lslea and LsP5CS) and ultra-structural changes. Theis review identifies certain lesser explored areas such as molecular and ultra-structural changes where further research is needed for better understanding of symbiosis with reference to salt stress for optimum usage of this technology in the field on a large scale. This review paper gives useful benchmark information for the development and prioritization of future research programmes. PMID:19815570

ER-mediated stress induces mitochondrial-dependent caspases activation in NT2 neuron-like cells.

PubMed

Arduino, Daniela M; Esteves, A Raquel; Domingues, A Filipa; Pereira, Claudia M F; Cardoso, Sandra M; Oliveira, Catarina R

2009-11-30

Recent studies have revealed that endoplasmic reticulum (ER) disturbance is involved in the pathophysiology of neurodegenerative disorders, contributing to the activation of the ER stress-mediated apoptotic pathway. Therefore, we investigated here the molecular mechanisms underlying the ER-mitochondria axis, focusing on calcium as a potential mediator of cell death signals. Using NT2 cells treated with brefeldin A or tunicamycin, we observed that ER stress induces changes in the mitochondrial function, impairing mitochondrial membrane potential and distressing mitochondrial respiratory chain complex Moreover, stress stimuli at ER level evoked calcium fluxes between ER and mitochondria. Under these conditions, ER stress activated the unfolded protein response by an overexpression of GRP78, and also caspase-4 and-2, both involved upstream of caspase-9. Our findings show that ER and mitochondria interconnection plays a prominent role in the induction of neuronal cell death under particular stress circumstances.

Targeting the hallmarks of cancer with therapy-induced endoplasmic reticulum (ER) stress

PubMed Central

Garg, Abhishek D; Maes, Hannelore; van Vliet, Alexander R; Agostinis, Patrizia

2015-01-01

The endoplasmic reticulum (ER) is at the center of a number of vital cellular processes such as cell growth, death, and differentiation, crosstalk with immune or stromal cells, and maintenance of proteostasis or homeostasis, and ER functions have implications for various pathologies including cancer. Recently, a number of major hallmarks of cancer have been delineated that are expected to facilitate the development of anticancer therapies. However, therapeutic induction of ER stress as a strategy to broadly target multiple hallmarks of cancer has been seldom discussed despite the fact that several primary or secondary ER stress-inducing therapies have been found to exhibit positive clinical activity in cancer patients. In the present review we provide a brief historical overview of the major discoveries and milestones in the field of ER stress biology with important implications for anticancer therapy. Furthermore, we comprehensively discuss possible strategies enabling the targeting of multiple hallmarks of cancer with therapy-induced ER stress. PMID:27308392

4-PBA improves lithium-induced nephrogenic diabetes insipidus by attenuating ER stress.

PubMed

Zheng, Peili; Lin, Yu; Wang, Feifei; Luo, Renfei; Zhang, Tiezheng; Hu, Shan; Feng, Pinning; Liang, Xinling; Li, Chunling; Wang, Weidong

2016-10-01

Endoplasmic reticulum (ER) stress has been implicated in some types of glomerular and tubular disorders. The objectives of this study were to elucidate the role of ER stress in lithium-induced nephrogenic diabetes insipidus (NDI) and to investigate whether attenuation of ER stress by 4-phenylbutyric acid (4-PBA) improves urinary concentrating defect in lithium-treated rats. Wistar rats received lithium (40 mmol/kg food), 4-PBA (320 mg/kg body wt by gavage every day), or no treatment (control) for 2 wk, and they were dehydrated for 24 h before euthanasia. Lithium treatment resulted in increased urine output and decreased urinary osmolality, which was significantly improved by 4-PBA. 4-PBA also prevented reduced protein expression of aquaporin-2 (AQP2), pS256-AQP2, and pS261-AQP2 in the inner medulla of kidneys from lithium-treated rats after 24-h dehydration. Lithium treatment resulted in increased expression of ER stress markers in the inner medulla, which was associated with dilated cisternae and expansion of ER in the inner medullary collecting duct (IMCD) principal cells. Confocal immunofluorescence studies showed colocalization of a molecular chaperone, binding IgG protein (BiP), with AQP2 in principal cells. Immunohistochemistry demonstrated increased intracellular expression of BiP and decreased AQP2 expression in IMCD principal cells of kidneys from lithium-treated rats. 4-PBA attenuated expression of ER stress markers and recovered ER morphology. In IMCD suspensions isolated from lithium-treated rats, 4-PBA incubation was also associated with increased AQP2 expression and ameliorated ER stress. In conclusion, in experimental lithium-induced NDI, 4-PBA improved the urinary concentrating defect and increased AQP2 expression, likely via attenuating ER stress in IMCD principal cells. Copyright © 2016 the American Physiological Society.

Causes and Alleviation of Occupational Stress in Child Care Work

ERIC Educational Resources Information Center

Dillenburger, Karola

2004-01-01

Occupational stress in not a new phenomenon in the working population. However, in the helping professions it has only recently attracted attention. The survey reported here was carried out in order to assess the extent of occupational stress, identify its causes, and suggest ways in which occupational stress can be alleviated. Field social…

Exocrine pancreas ER stress is differentially induced by different fatty acids.

PubMed

Danino, Hila; Ben-Dror, Karin; Birk, Ruth

2015-12-10

Exocrine pancreas acinar cells have a highly developed endoplasmic reticulum (ER), accommodating their high protein production rate. Overload of dietary fat (typical to obesity) is a recognized risk factor in pancreatitis and pancreatic cancer. Dietary fat, especially saturated fat, has been suggested by others and us to induce an acinar lipotoxic effect. The effect of different dietary fatty acids on the ER stress response is unknown. We studied the effect of acute (24h) challenge with different fatty acids (saturated, mono and poly-unsaturated) at different concentrations (between 200 and 500µM, typical to normal and obese states, respectively), testing fat accumulation, ER stress indicators, X-box binding protein 1 (Xbp1) splicing and nuclear translocation, as well as unfolded protein response (UPR) transcripts and protein levels using exocrine pancreas acinar AR42J and primary cells. Acute exposure of AR42J cells to different fatty acids caused increased accumulation of triglycerides, dependent on the type of fat. Different FAs had different effects on ER stress: most notably, saturated palmitic acid significantly affected the UPR response, as demonstrated by altered Xbp1 splicing, elevation in transcript levels of UPR (Xbp, CHOP, Bip) and immune factors (Tnfα, Tgfβ), and enhanced Xbp1 protein levels and Xbp1 time-dependent nuclear translocation. Poly-unsaturated FAs caused milder elevation of ER stress markers, while mono-unsaturated oleic acid attenuated the ER stress response. Thus, various fatty acids differentially affect acinar cell fat accumulation and, apart from oleic acid, induce ER stress. The differential effect of the various fatty acids could have potential nutritional and therapeutic implications. Copyright © 2015 Elsevier Inc. All rights reserved.

Cocaine induces astrocytosis through ER stress-mediated activation of autophagy

PubMed Central

Periyasamy, Palsamy; Guo, Ming-Lei; Buch, Shilpa

2016-01-01

ABSTRACT Cocaine is known to induce inflammation, thereby contributing in part, to the pathogenesis of neurodegeneration. A recent study from our lab has revealed a link between macroautophagy/autophagy and microglial activation. The current study was aimed at investigating whether cocaine could also mediate activation of astrocytes and, whether this process involved induction of autophagy. Our findings demonstrated that cocaine mediated the activation of astrocytes by altering the levels of autophagy markers, such as BECN1, ATG5, MAP1LC3B-II, and SQSTM1 in both human A172 astrocytoma cells and primary human astrocytes. Furthermore, cocaine treatment resulted in increased formation of endogenous MAP1LC3B puncta in human astrocytes. Additionally, astrocytes transfected with the GFP-MAP1LC3B plasmid also demonstrated cocaine-mediated upregulation of the green fluorescent MAP1LC3B puncta. Cocaine-mediated induction of autophagy involved upstream activation of ER stress proteins such as EIF2AK3, ERN1, ATF6 since blockage of autophagy using either pharmacological or gene-silencing approaches, had no effect on cocaine-mediated induction of ER stress. Using both pharmacological and gene-silencing approaches to block either ER stress or autophagy, our findings demonstrated that cocaine-induced activation of astrocytes (measured by increased levels of GFAP) involved sequential activation of ER stress and autophagy. Cocaine-mediated-increased upregulation of GFAP correlated with increased expression of proinflammatory mediators such as TNF, IL1B, and IL6. In conclusion, these findings reveal an association between ER stress-mediated autophagy and astrogliosis in cocaine-treated astrocytes. Intervention of ER stress and/or autophagy signaling would thus be promising therapeutic targets for abrogating cocaine-mediated neuroinflammation. PMID:27337297

Cocaine induces astrocytosis through ER stress-mediated activation of autophagy.

PubMed

Periyasamy, Palsamy; Guo, Ming-Lei; Buch, Shilpa

2016-08-02

Cocaine is known to induce inflammation, thereby contributing in part, to the pathogenesis of neurodegeneration. A recent study from our lab has revealed a link between macroautophagy/autophagy and microglial activation. The current study was aimed at investigating whether cocaine could also mediate activation of astrocytes and, whether this process involved induction of autophagy. Our findings demonstrated that cocaine mediated the activation of astrocytes by altering the levels of autophagy markers, such as BECN1, ATG5, MAP1LC3B-II, and SQSTM1 in both human A172 astrocytoma cells and primary human astrocytes. Furthermore, cocaine treatment resulted in increased formation of endogenous MAP1LC3B puncta in human astrocytes. Additionally, astrocytes transfected with the GFP-MAP1LC3B plasmid also demonstrated cocaine-mediated upregulation of the green fluorescent MAP1LC3B puncta. Cocaine-mediated induction of autophagy involved upstream activation of ER stress proteins such as EIF2AK3, ERN1, ATF6 since blockage of autophagy using either pharmacological or gene-silencing approaches, had no effect on cocaine-mediated induction of ER stress. Using both pharmacological and gene-silencing approaches to block either ER stress or autophagy, our findings demonstrated that cocaine-induced activation of astrocytes (measured by increased levels of GFAP) involved sequential activation of ER stress and autophagy. Cocaine-mediated-increased upregulation of GFAP correlated with increased expression of proinflammatory mediators such as TNF, IL1B, and IL6. In conclusion, these findings reveal an association between ER stress-mediated autophagy and astrogliosis in cocaine-treated astrocytes. Intervention of ER stress and/or autophagy signaling would thus be promising therapeutic targets for abrogating cocaine-mediated neuroinflammation.

New Insights into the Pathogenesis of Alcohol-Induced ER Stress and Liver Diseases.

PubMed

Ji, Cheng

2014-01-01

Alcohol-induced liver disease increasingly contributes to human mortality worldwide. Alcohol-induced endoplasmic reticulum (ER) stress and disruption of cellular protein homeostasis have recently been established as a significant mechanism contributing to liver diseases. The alcohol-induced ER stress occurs not only in cultured hepatocytes but also  in vivo  in the livers of several species including mouse, rat, minipigs, zebrafish, and humans. Identified causes for the ER stress include acetaldehyde, oxidative stress, impaired one carbon metabolism, toxic lipid species, insulin resistance, disrupted calcium homeostasis, and aberrant epigenetic modifications. Importance of each of the causes in alcohol-induced liver injury depends on doses, duration and patterns of alcohol exposure, genetic disposition, environmental factors, cross-talks with other pathogenic pathways, and stages of liver disease. The ER stress may occur more or less all the time during alcohol consumption, which interferes with hepatic protein homeostasis, proliferation, and cell cycle progression promoting development of advanced liver diseases. Emerging evidence indicates that long-term alcohol consumption and ER stress may directly be involved in hepatocellular carcinogenesis (HCC). Dissecting ER stress signaling pathways leading to tumorigenesis will uncover potential therapeutic targets for intervention and treatment of human alcoholics with liver cancer.

Coregulation of endoplasmic reticulum stress and oxidative stress in neuropathic pain and disinhibition of the spinal nociceptive circuitry.

PubMed

Ge, Yanhu; Jiao, Yingfu; Li, Peiying; Xiang, Zhenghua; Li, Zhi; Wang, Long; Li, Wenqian; Gao, Hao; Shao, Jiayun; Wen, Daxiang; Yu, Weifeng

2018-05-01

The accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) lumen leads to ER stress, which is related to cellular reactive oxygen species production. Neuropathic pain may result from spinal dorsal horn (SDH) ER stress. In this study, we examined the cause-effect relationship between ER stress and neuropathic pain using the spinal nerve ligation (SNL) rat model. We showed that ER stress was mutually promotive with oxidative stress during the process. We also tested the hypothesis that spinal sensitization arose from reduced activities of GABA-ergic interneurons and that spinal sensitization was mediated by SDH ER stress. Other important findings in this study including the following: (1) nociceptive behavior was alleviated in SNL rat as long as tauroursodeoxycholic acid injections were repeated to inhibit ER stress; (2) inducing SDH ER stress in healthy rat resulted in mechanical hyperalgesia; (3) blocking protein disulfide isomerase pharmacologically reduced ER stress and nociceptive behavior in SNL rat; (4) cells in the dorsal horn with elevated ER stress were mainly neurons; and (5) whole-cell recordings made in slide preparations revealed significant inhibition of GABA-ergic interneuron activity in the dorsal horn with ER stress vs in the healthy dorsal horn. Taken together, results of the current study demonstrate that coregulation of ER stress and oxidative stress played an important role in neuropathic pain process. Inhibiting SDH ER stress could be a potential novel strategy to manage neuropathic pain.

Coxsackievirus A16 infection triggers apoptosis in RD cells by inducing ER stress.

PubMed

Zhu, Guoguo; Zheng, Yingcheng; Zhang, Lianglu; Shi, Yingying; Li, Wenhua; Liu, Zhongchun; Peng, Biwen; Yin, Jun; Liu, Wanhong; He, Xiaohua

2013-11-29

Coxsackievirus A16 (CA16) infection, which is responsible for hand, foot and mouth disease (HFMD), has become a common health problem in Asia due to the prevalence of the virus. Thus, it is important to understand the pathogenesis of CA16 infection. Viruses that induce endoplasmic reticulum (ER) stress are confronted with the unfolded protein response (UPR), which may lead to apoptotic cell death and influence viral replication. In this study, we found that CA16 infection could induce apoptosis and ER stress in RD cells. Interestingly, apoptosis via the activation of caspase-3, -8 and -9 in the extrinsic or intrinsic apoptotic pathways in RD cells was inhibited by 4-phenyl butyric acid (4PBA), a chemical chaperone that reduces ER stress. These results suggest that CA16 infection leads to ER stress, which in turn results in prolonged ER stress-induced apoptosis. This study provides a new basis for understanding CA16 infection and host responses. Copyright © 2013 Elsevier Inc. All rights reserved.

Resveratrol and caloric restriction prevent hepatic steatosis by regulating SIRT1-autophagy pathway and alleviating endoplasmic reticulum stress in high-fat diet-fed rats

PubMed Central

Zhang, Guofu; Bu, Yongjun; Zhang, Guanghui; Zhao, Xiangmei

2017-01-01

Background Studies have demonstrated that resveratrol (a natural polyphenol) and caloric restriction activate Sirtuin-1 (SIRT1) and induce autophagy. Furthermore, autophagy is induced by the SIRT1-FoxO signaling pathway and was recently shown to be a critical protective mechanism against non-alcoholic fatty liver disease (NAFLD) development. We aimed to compare the effects of resveratrol and caloric restriction on hepatic lipid metabolism and elucidate the mechanism by which resveratrol supplementation and caloric restriction alleviate hepatosteatosis by examining the molecular interplay between SIRT1 and autophagy. Methods and results Eight-week-old male Wistar rats (40) were divided into four groups: the STD group, which was fed a standard chow diet; the HFD group, which was fed a high-fat diet; HFD-RES group, which was fed a high-fat diet plus resveratrol (200 mg/kg.bw); and the HFD-CR group, which was fed a high-fat diet in portions containing 70% of the mean intake of the HFD group rats. The groups were maintained for 18 weeks. Metabolic parameters, Oil Red O and hematoxylin-eosin staining of the liver, and the mRNA and protein expression of SIRT1, autophagy markers and endoplasmic reticulum(ER) stress-associated genes in the liver were assessed after the 18-week treatment. We found that resveratrol (200 mg/kg bw) and caloric restriction (30%) partially prevented hepatic steatosis and hepatocyte ballooning, increased the expression of SIRT1 and autophagy markers while decreasing ER stress markers in the liver and alleviated lipid metabolism disorder. Moreover, caloric restriction provided superior protection against HFD-induced hepatic fatty accumulation compared with resveratrol and the effects were associated with decreased total energy intake and body weight. Conclusion We conclude that the SIRT1-autophagy pathway and decreased ER stress are universally required for the protective effects of moderate caloric restriction (30%) and resveratrol (a

Resveratrol and caloric restriction prevent hepatic steatosis by regulating SIRT1-autophagy pathway and alleviating endoplasmic reticulum stress in high-fat diet-fed rats.

PubMed

Ding, Shibin; Jiang, Jinjin; Zhang, Guofu; Bu, Yongjun; Zhang, Guanghui; Zhao, Xiangmei

2017-01-01

Studies have demonstrated that resveratrol (a natural polyphenol) and caloric restriction activate Sirtuin-1 (SIRT1) and induce autophagy. Furthermore, autophagy is induced by the SIRT1-FoxO signaling pathway and was recently shown to be a critical protective mechanism against non-alcoholic fatty liver disease (NAFLD) development. We aimed to compare the effects of resveratrol and caloric restriction on hepatic lipid metabolism and elucidate the mechanism by which resveratrol supplementation and caloric restriction alleviate hepatosteatosis by examining the molecular interplay between SIRT1 and autophagy. Eight-week-old male Wistar rats (40) were divided into four groups: the STD group, which was fed a standard chow diet; the HFD group, which was fed a high-fat diet; HFD-RES group, which was fed a high-fat diet plus resveratrol (200 mg/kg.bw); and the HFD-CR group, which was fed a high-fat diet in portions containing 70% of the mean intake of the HFD group rats. The groups were maintained for 18 weeks. Metabolic parameters, Oil Red O and hematoxylin-eosin staining of the liver, and the mRNA and protein expression of SIRT1, autophagy markers and endoplasmic reticulum(ER) stress-associated genes in the liver were assessed after the 18-week treatment. We found that resveratrol (200 mg/kg bw) and caloric restriction (30%) partially prevented hepatic steatosis and hepatocyte ballooning, increased the expression of SIRT1 and autophagy markers while decreasing ER stress markers in the liver and alleviated lipid metabolism disorder. Moreover, caloric restriction provided superior protection against HFD-induced hepatic fatty accumulation compared with resveratrol and the effects were associated with decreased total energy intake and body weight. We conclude that the SIRT1-autophagy pathway and decreased ER stress are universally required for the protective effects of moderate caloric restriction (30%) and resveratrol (a pharmacological SIRT1 activator) supplementation

The APP intracellular domain (AICD) potentiates ER stress-induced apoptosis.

PubMed

Kögel, Donat; Concannon, Caoimhín G; Müller, Thorsten; König, Hildegard; Bonner, Caroline; Poeschel, Simone; Chang, Steffi; Egensperger, Rupert; Prehn, Jochen H M

2012-09-01

Here we employed human SHEP neuroblastoma cells either stably or inducibly expressing the amyloid precursor protein (APP) intracellular domain (AICD) to investigate its ability to modulate stress-induced cell death. Analysis of effector caspase activation revealed that AICD overexpression was specifically associated with an increased sensitivity to apoptosis induced by the 2 endoplasmic reticulum (ER) stressors thapsigargin and tunicamycin, but not by staurosporine (STS). Basal and ER stress-induced expression of Bip/Grp78 and C/EBP-homologous protein/GADD153 were not altered by AICD implying that AICD potentiated cell death downstream or independent of the conserved unfolded protein response (UPR). Interestingly, quantitative polymerase chain reaction analysis and reporter gene assays revealed that AICD significantly downregulated messenger RNA levels of the Alzheimer's disease susceptibility gene ApoJ/clusterin, indicating transcriptional repression. Knockdown of ApoJ/clusterin mimicked the effect of AICD on ER stress-induced apoptosis, but had no discernible effect on staurosporine-induced cell death. Our data suggest that altered levels of AICD may abolish the prosurvival function of ApoJ/clusterin and increase the susceptibility of neurons to ER stress-mediated cell death, a pathway that may contribute to the pathogenesis of Alzheimer's disease. Copyright © 2012 Elsevier Inc. All rights reserved.

Systemic effects of AGEs in ER stress induction in vivo.

PubMed

Adamopoulos, Christos; Mihailidou, Chrysovalantou; Grivaki, Christofora; Papavassiliou, Kostas A; Kiaris, Hippokratis; Piperi, Christina; Papavassiliou, Athanasios G

2016-08-01

Emerging evidence indicates that accumulation of advanced glycation end products (AGEs) in human tissues may contribute to cell injury, inflammation and apoptosis through induction of endoplasmic reticulum (ER) stress. Human metabolism relies on ER homeostasis for the coordinated response of all metabolic organs by controlling the synthesis and catabolism of various nutrients. In vitro studies have demonstrated AGE-induced enhancement of unfolded protein response (UPR) in different cell types including endothelial, neuronal, pancreatic cells and podocytes, suggesting this crosstalk as an underlying pathological mechanism that contributes to metabolic diseases. In this minireview, we describe in vivo studies undertaken by our group and others that demonstrate the diverse systemic effects of AGEs in ER stress induction in major metabolic tissues such as brain, kidney, liver and pancreas of normal mice. Administration of high-AGEs content diet to normal mice for the period of 4 weeks upergulates the mRNA and protein levels of ER chaperone Bip (GRP78) indicative of UPR initiation in all major metabolic organs and induces activation of the pivotal transcription factor XBP1 that regulates glucose and lipid metabolism. Furthermore, animals with genetic ablation of UPR-activated transcription factor C/EBP homologous protein CHOP allocated in high-AGEs diet, exhibited relative resistance to UPR induction (BiP levels) and XBP1 activation in major metabolic organs. Since CHOP presents a critical mediator that links accumulation and aggregation of unfolded proteins with induction of oxidative stress and ER stress-related apoptosis, it is revealed as an important molecular target for the management of metabolic diseases.

ER-stress and apoptosis: molecular mechanisms and potential relevance in infection.

PubMed

Häcker, Georg

2014-10-01

During ER-stress, one of the responses a cell can choose is apoptosis. Apoptosis generally is a cell's preferred response when other control mechanisms are overwhelmed. We now have a reasonably clear molecular picture what is happening once the apoptotic apparatus has been started. Unclear however are the majority of the upstream pathways that connect other signalling to apoptosis. During ER-stress, confirmed apoptosis-regulating targets are pro- and anti-apoptotic proteins of the Bcl-2-family, whose concerted action induces apoptosis. I will here discuss how mitochondrial apoptosis is triggered, how this is linked to the ER-stress response and in what way this may be relevant during microbial infections. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Insulin/IGF-1 signaling mutants reprogram ER stress response regulators to promote longevity.

PubMed

Henis-Korenblit, Sivan; Zhang, Peichuan; Hansen, Malene; McCormick, Mark; Lee, Seung-Jae; Cary, Michael; Kenyon, Cynthia

2010-05-25

When unfolded proteins accumulate in the endoplasmic reticulum (ER), the unfolded protein response is activated. This ER stress response restores ER homeostasis by coordinating processes that decrease translation, degrade misfolded proteins, and increase the levels of ER-resident chaperones. Ribonuclease inositol-requiring protein-1 (IRE-1), an endoribonuclease that mediates unconventional splicing, and its target, the XBP-1 transcription factor, are key mediators of the unfolded protein response. In this study, we show that in Caenorhabditis elegans insulin/IGF-1 pathway mutants, IRE-1 and XBP-1 promote lifespan extension and enhance resistance to ER stress. We show that these effects are not achieved simply by increasing the level of spliced xbp-1 mRNA and expression of XBP-1's normal target genes. Instead, in insulin/IGF-1 pathway mutants, XBP-1 collaborates with DAF-16, a FOXO-transcription factor that is activated in these mutants, to enhance ER stress resistance and to activate new genes that promote longevity.

WWOX sensitises ovarian cancer cells to paclitaxel via modulation of the ER stress response.

PubMed

Janczar, Szymon; Nautiyal, Jaya; Xiao, Yi; Curry, Edward; Sun, Mingjun; Zanini, Elisa; Paige, Adam Jw; Gabra, Hani

2017-07-27

There are clear gaps in our understanding of genes and pathways through which cancer cells facilitate survival strategies as they become chemoresistant. Paclitaxel is used in the treatment of many cancers, but development of drug resistance is common. Along with being an antimitotic agent paclitaxel also activates endoplasmic reticulum (ER) stress. Here, we examine the role of WWOX (WW domain containing oxidoreductase), a gene frequently lost in several cancers, in mediating paclitaxel response. We examine the ER stress-mediated apoptotic response to paclitaxel in WWOX-transfected epithelial ovarian cancer (EOC) cells and following siRNA knockdown of WWOX. We show that WWOX-induced apoptosis following exposure of EOC cells to paclitaxel is related to ER stress and independent of the antimitotic action of taxanes. The apoptotic response to ER stress induced by WWOX re-expression could be reversed by WWOX siRNA in EOC cells. We report that paclitaxel treatment activates both the IRE-1 and PERK kinases and that the increase in paclitaxel-mediated cell death through WWOX is dependent on active ER stress pathway. Log-rank analysis of overall survival (OS) and progression-free survival (PFS) in two prominent EOC microarray data sets (Tothill and The Cancer Genome Atlas), encompassing ~800 patients in total, confirmed clinical relevance to our findings. High WWOX mRNA expression predicted longer OS and PFS in patients treated with paclitaxel, but not in patients who were treated with only cisplatin. The association of WWOX and survival was dependent on the expression level of glucose-related protein 78 (GRP78), a key ER stress marker in paclitaxel-treated patients. We conclude that WWOX sensitises EOC to paclitaxel via ER stress-induced apoptosis, and predicts clinical outcome in patients. Thus, ER stress response mechanisms could be targeted to overcome chemoresistance in cancer.

Particle-induced SIRT1 downregulation promotes osteoclastogenesis and osteolysis through ER stress regulation.

PubMed

Zhang, Liang; Bao, Dongmei; Li, Peng; Lu, Zhidong; Pang, Long; Chen, Zhirong; Guo, Haohui; Gao, Zhihui; Jin, Qunhua

2018-08-01

Sirtuin 1 (SIRT1) downregulation has been found to be induced by wear particles in aseptic prosthesis loosening (APL). Osteoclastogenesis and osteoclast activation are the main pathological factors associated with APL. However, whether SIRT1 downregulation contributes to the formation and activation of osteoclasts through the induction of endoplasmic reticulum (ER) stress is unclear. To address this, an osteolysis mouse model was used in which animals were treated with the SIRT1 activator, resveratrol (RES), or an ER stress inhibitor, 4-PBA, for two weeks. Osteolysis, osteoclastogenesis, and morphologic alteration of calvariae were observed by toluidine blue, TRAP, and H&E staining. SIRT1 expression and ER stress were evaluated by western blot analysis. In vitro, mouse macrophage RAW 264.7 cells were treated with polyethylene (PE) particles alone or combined with either RES or 4-PBA, and SIRT1 expression and ER stress were measured using western blot assays. Osteoclast differentiation was determined through TRAP staining. Osteoclast activation was evaluated by culturing osteoclast cells on bone slices followed by toluidine blue staining. Mechanistically, osteoclastogenesis-related MAPK activation, NFATc1 and c-Fos expression, and NF-κB translocation were determined. Both in vivo and in vitro experimental results indicated that PE particles induced SIRT1 downregulation and enhanced ER stress. SIRT1 activator RES and ER stress inhibitor 4-PBA significantly suppressed PE particle-induced osteoclast differentiation and osteolysis. In vitro experimental results showed that 4-PBA suppressed PE particle-induced ERK1/2, p38, and JNK activation, NFATc1 and c-Fos upregulation, as well as NF-κB p65 nucleus translocation. PE particle-induced downregulation of SIRT1 enhances ER stress and promotes osteoclast proliferation and bone resorption through regulation of c-Fos, NFATc1, and the MAPK and NF-κB signaling pathways. Copyright © 2018 Elsevier Masson SAS. All rights

Evidence that endoplasmic reticulum (ER) stress and caspase-4 activation occur in human neutrophils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Binet, Francois; Chiasson, Sonia; Girard, Denis, E-mail: denis.girard@iaf.inrs.ca

2010-01-01

Apoptosis can result from activation of three major pathways: the extrinsic, the intrinsic, and the most recently identified endoplasmic reticulum (ER) stress-mediated pathway. While the two former pathways are known to be operational in human polymorphonuclear neutrophils (PMNs), the existence of the ER stress-mediated pathway, generally involving caspase-4, has never been reported in these cells. Recently, we have documented that arsenic trioxide (ATO) induced apoptosis in human PMNs by a mechanism that needs to be further investigated. In this study, using immunofluorescence and electron microscopy, we present evidence of ER alterations in PMNs activated by the ER stress inducer arsenicmore » trioxide (ATO). Several key players of the unfolded protein response, including GRP78, GADD153, ATF6, XBP1 and eIF2{alpha} are expressed and activated in PMNs treated with ATO or other ER stress inducers. Although caspase-4 is expressed and activated in neutrophils, treatment with a caspase-4 inhibitor did not attenuate the pro-apoptotic effect of ATO at a concentration that reverses caspase-4 processing and activation. Our results demonstrate for the first time that the ER stress-mediated apoptotic pathway operates in human neutrophils.« less

Valsartan protects HK-2 cells from contrast media-induced apoptosis by inhibiting endoplasmic reticulum stress.

PubMed

Peng, Ping-An; Wang, Le; Ma, Qian; Xin, Yi; Zhang, Ou; Han, Hong-Ya; Liu, Xiao-Li; Ji, Qing-Wei; Zhou, Yu-Jie; Zhao, Ying-Xin

2015-12-01

Contrast-induced acute kidney injury (CI-AKI) is associated with increasing in-hospital and long-term adverse clinical outcomes in high-risk patients undergoing percutaneous coronary intervention (PCI). Contrast media (CM)-induced renal tubular cell apoptosis is reported to participate in this process by activating endoplasmic reticulum (ER) stress. An angiotensin II type 1 receptor (AT1R) antagonist can alleviate ER stress-induced renal apoptosis in streptozotocin (STZ)-induced diabetic mice and can reduce CM-induced renal apoptosis by reducing oxidative stress and reversing the enhancement of bax mRNA and the reduction of bcl-2 mRNA, but the effect of the AT1R blocker on ER stress in the pathogenesis of CI-AKI is still unknown. In this study, we explored the effect of valsartan on meglumine diatrizoate-induced human renal tubular cell apoptosis by measuring changes in ER stress-related biomarkers. The results showed that meglumine diatrizoate caused significant cell apoptosis by up-regulating the expression of ER stress markers, including glucose-regulated protein 78 (GRP78), activating transcription factor 4 (ATF4), CCAAT/enhancer-binding protein-homologous protein (CHOP) and caspase 12, in a time- and dose-dependent manner, which could be alleviated by preincubation with valsartan. In conclusion, valsartan had a potential nephroprotective effect on meglumine diatrizoate-induced renal cell apoptosis by inhibiting ER stress. © 2015 International Federation for Cell Biology.

ER stress in Alzheimer's disease: a novel neuronal trigger for inflammation and Alzheimer's pathology

PubMed Central

2009-01-01

The endoplasmic reticulum (ER) is involved in several crucial cellular functions, e.g. protein folding and quality control, maintenance of Ca2+ balance, and cholesterol synthesis. Many genetic and environmental insults can disturb the function of ER and induce ER stress. ER contains three branches of stress sensors, i.e. IRE1, PERK and ATF6 transducers, which recognize the misfolding of proteins in ER and activate a complex signaling network to generate the unfolded protein response (UPR). Alzheimer's disease (AD) is a progressive neurodegenerative disorder involving misfolding and aggregation of proteins in conjunction with prolonged cellular stress, e.g. in redox regulation and Ca2+ homeostasis. Emerging evidence indicates that the UPR is activated in neurons but not in glial cells in AD brains. Neurons display pPERK, peIF2α and pIRE1α immunostaining along with abundant diffuse staining of phosphorylated tau protein. Recent studies have demonstrated that ER stress can also induce an inflammatory response via different UPR transducers. The most potent pathways are IRE1-TRAF2, PERK-eIF2α, PERK-GSK-3, ATF6-CREBH, as well as inflammatory caspase-induced signaling pathways. We will describe the mechanisms which could link the ER stress of neurons to the activation of the inflammatory response and the evolution of pathological changes in AD. PMID:20035627

Residual stress alleviation of aircraft metal structures reinforced with filamentary composites

NASA Technical Reports Server (NTRS)

Kelly, J. B.; June, R. R.

1973-01-01

Methods to eliminate or reduce residual stresses in aircraft metal structures reinforced by filamentary composites are discussed. Residual stress level reductions were achieved by modifying the manufacturing procedures used during adhesive bonding. The residual stress alleviation techniques involved various forms of mechanical constraint which were applied to the components during bonding. Nine methods were evaluated, covering a wide range in complexity. All methods investigated during the program affected the residual stress level. In general, residual stresses were reduced by 70 percent or more from the stress level produced by conventional adhesive bonding procedures.

ER stress response mechanisms in the pathogenic yeast Candida glabrata and their roles in virulence

PubMed Central

Miyazaki, Taiga; Kohno, Shigeru

2014-01-01

The maintenance of endoplasmic reticulum (ER) homeostasis is critical for numerous aspects of cell physiology. Eukaryotic cells respond to the accumulation of misfolded proteins in the ER (ER stress) by activating the unfolded protein response (UPR), an intracellular signaling pathway that adjusts the folding capacity of the ER. Recent studies of several pathogenic fungi have revealed that the UPR is important for antifungal resistance and virulence; therefore, the pathway has attracted much attention as a potential therapeutic target. While the UPR is highly conserved among eukaryotes, our group recently discovered that the pathogenic yeast Candida glabrata lacks the typical fungal UPR, but possesses alternative mechanisms to cope with ER stress. This review summarizes how C. glabrata responds to ER stress and discusses the impacts of ER quality control systems on antifungal resistance and virulence. PMID:24335436

Melatonin Has the Potential to Alleviate Cinnamic Acid Stress in Cucumber Seedlings

PubMed Central

Li, Juanqi; Li, Yang; Tian, Yongqiang; Qu, Mei; Zhang, Wenna; Gao, Lihong

2017-01-01

Cinnamic acid (CA), which is a well-known major autotoxin secreted by the roots in cucumber continuous cropping, has been proven to exhibit inhibitory regulation of plant morphogenesis and development. Melatonin (MT) has been recently demonstrated to play important roles in alleviating plant abiotic stresses. To investigate whether MT supplementation could improve cucumber seedling growth under CA stress, we treated cucumber seeds and seedlings with/without MT under CA- or non-stress conditions, and then tested their effects on cucumber seedling growth, morphology, nutrient element content, and plant hormone. Overall, 10 μM MT best rescued cucumber seedling growth under 0.4 mM CA stress. MT was found to alleviate CA-stressed seedling growth by increasing the growth rates of cotyledons and leaves and by stimulating lateral root growth. Additionally, MT increased the allocation of newly gained dry weight in roots and improved the tolerance of cucumber seedlings to CA stress by altering the nutrient elements and hormone contents of the whole plant. These results strongly suggest that the application of MT can effectively improve cucumber seedling tolerance to CA stress through the perception and integration of morphology, nutrient element content and plant hormone signaling crosstalk. PMID:28751899

Excessive ER stress and the resulting autophagic flux dysfunction contribute to fluoride-induced neurotoxicity.

PubMed

Niu, Qiang; Chen, Jingwen; Xia, Tao; Li, Pei; Zhou, Guoyu; Xu, Chunyan; Zhao, Qian; Dong, Lixin; Zhang, Shun; Wang, Aiguo

2018-02-01

Fluoride is capable of inducing neurotoxicity, but its mechanisms remain elusive. This study aimed to explore the roles of endoplasmic reticulum (ER) stress and autophagy in sodium fluoride (NaF)-induced neurotoxicity, focusing on the regulating role of ER stress in autophagy. The in vivo results demonstrated that NaF exposure impaired the learning and memory capabilities of rats, and resulted in histological and ultrastructural abnormalities in rat hippocampus. Moreover, NaF exposure induced excessive ER stress and associated apoptosis, as manifested by elevated IRE1α, GRP78, cleaved caspase-12 and cleaved-caspase-3, as well as defective autophagy, as shown by increased Beclin1, LC3-II and p62 expression in hippocampus. Consistently, the in vitro results further verified the findings of in vivo study that NaF induced excessive ER stress and defective autophagy in SH-SY5Y cells. Notably, inhibition of autophagy in NaF-treated SH-SY5Y cells with Wortmannin or Chloroquine decreased, while induction of autophagy by Rapamycin increased the cell viability. These results were correlated well with the immunofluorescence observations, thus confirming the pivotal role of autophagic flux dysfunction in NaF-induced cell death. Importantly, mitigation of ER stress by 4-phenylbutyrate in NaF-treated SH-SY5Y cells inhibited the expressions of autophagy markers, and decreased cell apoptosis. Taken together, these data suggest that neuronal death resulted from excessive ER stress and autophagic flux dysfunction contributes to fluoride-elicited neurotoxicity. Moreover, the autophagic flux dysfunction was mediated by excessive ER stress, which provided novel insight into a better understanding of fluoride-induced neurotoxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Increased intracellular proteolysis reduces disease severity in an ER stress-associated dwarfism.

PubMed

Mullan, Lorna A; Mularczyk, Ewa J; Kung, Louise H; Forouhan, Mitra; Wragg, Jordan Ma; Goodacre, Royston; Bateman, John F; Swanton, Eileithyia; Briggs, Michael D; Boot-Handford, Raymond P

2017-10-02

The short-limbed dwarfism metaphyseal chondrodysplasia type Schmid (MCDS) is linked to mutations in type X collagen, which increase ER stress by inducing misfolding of the mutant protein and subsequently disrupting hypertrophic chondrocyte differentiation. Here, we show that carbamazepine (CBZ), an autophagy-stimulating drug that is clinically approved for the treatment of seizures and bipolar disease, reduced the ER stress induced by 4 different MCDS-causing mutant forms of collagen X in human cell culture. Depending on the nature of the mutation, CBZ application stimulated proteolysis of misfolded collagen X by either autophagy or proteasomal degradation, thereby reducing intracellular accumulation of mutant collagen. In MCDS mice expressing the Col10a1.pN617K mutation, CBZ reduced the MCDS-associated expansion of the growth plate hypertrophic zone, attenuated enhanced expression of ER stress markers such as Bip and Atf4, increased bone growth, and reduced skeletal dysplasia. CBZ produced these beneficial effects by reducing the MCDS-associated abnormalities in hypertrophic chondrocyte differentiation. Stimulation of intracellular proteolysis using CBZ treatment may therefore be a clinically viable way of treating the ER stress-associated dwarfism MCDS.

ER Stress-Mediated Signaling: Action Potential and Ca(2+) as Key Players.

PubMed

Bahar, Entaz; Kim, Hyongsuk; Yoon, Hyonok

2016-09-15

The proper functioning of the endoplasmic reticulum (ER) is crucial for multiple cellular activities and survival. Disturbances in the normal ER functions lead to the accumulation and aggregation of unfolded proteins, which initiates an adaptive response, the unfolded protein response (UPR), in order to regain normal ER functions. Failure to activate the adaptive response initiates the process of programmed cell death or apoptosis. Apoptosis plays an important role in cell elimination, which is essential for embryogenesis, development, and tissue homeostasis. Impaired apoptosis can lead to the development of various pathological conditions, such as neurodegenerative and autoimmune diseases, cancer, or acquired immune deficiency syndrome (AIDS). Calcium (Ca(2+)) is one of the key regulators of cell survival and it can induce ER stress-mediated apoptosis in response to various conditions. Ca(2+) regulates cell death both at the early and late stages of apoptosis. Severe Ca(2+) dysregulation can promote cell death through apoptosis. Action potential, an electrical signal transmitted along the neurons and muscle fibers, is important for conveying information to, from, and within the brain. Upon the initiation of the action potential, increased levels of cytosolic Ca(2+) (depolarization) lead to the activation of the ER stress response involved in the initiation of apoptosis. In this review, we discuss the involvement of Ca(2+) and action potential in ER stress-mediated apoptosis.

Reduction of Endoplasmic Reticulum Stress Improves Angiogenic Progenitor Cell function in a Mouse Model of Type 1 Diabetes.

PubMed

Bhatta, Maulasri; Chatpar, Krishna; Hu, Zihua; Wang, Joshua J; Zhang, Sarah X

2018-04-27

Persistent vascular injury and degeneration in diabetes are attributed in part to defective reparatory function of angiogenic cells. Our recent work implicates endoplasmic reticulum (ER) stress in high-glucose-induced bone marrow (BM) progenitor dysfunction. Herein, we investigated the in vivo role of ER stress in angiogenic abnormalities of streptozotocin-induced diabetic mice. Our data demonstrate that ER stress markers and inflammatory gene expression in BM mononuclear cells and hematopoietic progenitor cells increase dynamically with disease progression. Increased CHOP and cleaved caspase- 3 levels were observed in BM--derived early outgrowth cells (EOCs) after 3 months of diabetes. Inhibition of ER stress by ex vivo or in vivo chemical chaperone treatment significantly improved the generation and migration of diabetic EOCs while reducing apoptosis of these cells. Chemical chaperone treatment also increased the number of circulating angiogenic cells in peripheral blood, alleviated BM pathology, and enhanced retinal vascular repair following ischemia/reperfusion in diabetic mice. Mechanistically, knockdown of CHOP alleviated high-glucose-induced EOC dysfunction and mitigated apoptosis, suggesting a pivotal role of CHOP in mediating ER stress-associated angiogenic cell injury in diabetes. Together, our study suggests that targeting ER signaling may provide a promising and novel approach to enhancing angiogenic function in diabetes.

Endothelial NOS activation induces the blood-brain barrier disruption via ER stress following status epilepticus.

PubMed

Ko, Ah-Reum; Kim, Ji Yang; Hyun, Hye-Won; Kim, Ji-Eun

2015-10-05

The blood-brain barrier (BBB) maintains the unique brain microenvironment, which is separated from the systemic circulating system. Since the endoplasmic reticulum (ER) is an important cell organelle that is responsible for protein synthesis, the correct folding and sorting of proteins contributing to cell survivals, ER stress is a potential cause of cell damage in various diseases. Therefore, it would be worthy to explore the the relationship between the ER stress and BBB disruption during vasogenic edema formation induced by epileptogenic insults. In the present study, we investigated the roles of ER stress in vasogenic edema and its related events in rat epilepsy models provoked by pilocarpine-induced status epilepticus (SE). SE-induced eNOS activation induces BBB breakdown via up-regulation of GRP78 expression and dysfunction of SMI-71 (an endothelial BBB marker) in the piriform cortex (PC). In addition, caveolin-1 peptide (an eNOS inhibitor) effectively attenuated GRP78 expression and down-regulation of SMI-71. Taken together, our findings suggest that eNOS-mediated ER stress may participate in SE-induced vasogenic edema formation. Therefore, the modulation of ER stress may be a considerable strategy for therapy in impairments of endothelial cell function. Copyright © 2015 Elsevier B.V. All rights reserved.

ER Stress Inhibits Liver Fatty Acid Oxidation while Unmitigated Stress Leads to Anorexia-Induced Lipolysis and Both Liver and Kidney Steatosis.

PubMed

DeZwaan-McCabe, Diane; Sheldon, Ryan D; Gorecki, Michelle C; Guo, Deng-Fu; Gansemer, Erica R; Kaufman, Randal J; Rahmouni, Kamal; Gillum, Matthew P; Taylor, Eric B; Teesch, Lynn M; Rutkowski, D Thomas

2017-05-30

The unfolded protein response (UPR), induced by endoplasmic reticulum (ER) stress, regulates the expression of factors that restore protein folding homeostasis. However, in the liver and kidney, ER stress also leads to lipid accumulation, accompanied at least in the liver by transcriptional suppression of metabolic genes. The mechanisms of this accumulation, including which pathways contribute to the phenotype in each organ, are unclear. We combined gene expression profiling, biochemical assays, and untargeted lipidomics to understand the basis of stress-dependent lipid accumulation, taking advantage of enhanced hepatic and renal steatosis in mice lacking the ER stress sensor ATF6α. We found that impaired fatty acid oxidation contributed to the early development of steatosis in the liver but not the kidney, while anorexia-induced lipolysis promoted late triglyceride and free fatty acid accumulation in both organs. These findings provide evidence for both direct and indirect regulation of peripheral metabolism by ER stress. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Methane alleviates copper-induced seed germination inhibition and oxidative stress in Medicago sativa.

PubMed

Samma, Muhammad Kaleem; Zhou, Heng; Cui, Weiti; Zhu, Kaikai; Zhang, Jing; Shen, Wenbiao

2017-02-01

Recent results discovered the protective roles of methane (CH 4 ) against oxidative stress in animals. However, the possible physiological roles of CH 4 in plants are still unknown. By using physiological, histochemical and molecular approaches, the beneficial role of CH 4 in germinating alfalfa seeds upon copper (Cu) stress was evaluated. Endogenous production of CH 4 was significantly increased in Cu-stressed alfalfa seeds, which was mimicked by 0.39 mM CH 4 . The pretreatment with CH 4 significantly alleviated the inhibition of seed germination and seedling growth induced by Cu stress. Cu accumulation was obviously blocked as well. Meanwhile, α/β amylase activities and sugar contents were increased, all of which were consistent with the alleviation of seed germination inhibition triggered by CH 4 . The Cu-triggered oxidative stress was also mitigated, which was confirmed by the decrease of lipid peroxidation and reduction of Cu-induced loss of plasma membrane integrity in CH 4 -pretreated alfalfa seedlings. The results of antioxidant enzymes, including ascorbate peroxidase (APX), superoxide dismutase (SOD), catalase (CAT), and guaiacol peroxidase (POD) total or isozymatic activities, and corresponding transcripts (APX1/2, Cu/Zn SOD and Mn-SOD), indicated that CH 4 reestablished cellular redox homeostasis. Further, Cu-induced proline accumulation was partly impaired by CH 4 , which was supported by the alternation of proline metabolism. Together, these results indicated that CH 4 performs an advantageous effect on the alleviation of seed germination inhibition caused by Cu stress, and reestablishment of redox homeostasis mainly via increasing antioxidant defence.

Resveratrol Enhances Palmitate-Induced ER Stress and Apoptosis in Cancer Cells

PubMed Central

Rojas, Cristina; Pan-Castillo, Belén; Valls, Cristina; Pujadas, Gerard; Garcia-Vallve, Santi; Arola, Lluis; Mulero, Miquel

2014-01-01

Background Palmitate, a saturated fatty acid (FA), is known to induce toxicity and cell death in various types of cells. Resveratrol (RSV) is able to prevent pathogenesis and/or decelerate the progression of a variety of diseases. Several in vitro and in vivo studies have also shown a protective effect of RSV on fat accumulation induced by FAs. Additionally, endoplasmic reticulum (ER) stress has recently been linked to cellular adipogenic responses. To address the hypothesis that the RSV effect on excessive fat accumulation promoted by elevated saturated FAs could be partially mediated by a reduction of ER stress, we studied the RSV action on experimentally induced ER stress using palmitate in several cancer cell lines. Principal Findings We show that, unexpectedly, RSV promotes an amplification of palmitate toxicity and cell death and that this mechanism is likely due to a perturbation of palmitate accumulation in the triglyceride form and to a less important membrane fluidity variation. Additionally, RSV decreases radical oxygen species (ROS) generation in palmitate-treated cells but leads to enhanced X-box binding protein-1 (XBP1) splicing and C/EBP homologous protein (CHOP) expression. These molecular effects are induced simultaneously to caspase-3 cleavage, suggesting that RSV promotes palmitate lipoapoptosis primarily through an ER stress-dependent mechanism. Moreover, the lipotoxicity reversion induced by eicosapentaenoic acid (EPA) or by a liver X receptor (LXR) agonist reinforces the hypothesis that RSV-mediated inhibition of palmitate channeling into triglyceride pools could be a key factor in the aggravation of palmitate-induced cytotoxicity. Conclusions Our results suggest that RSV exerts its cytotoxic role in cancer cells exposed to a saturated FA context primarily by triglyceride accumulation inhibition, probably leading to an intracellular palmitate accumulation that triggers a lipid-mediated cell death. Additionally, this cell death is promoted by

Obesity-induced endoplasmic reticulum stress causes chronic inflammation in adipose tissue.

PubMed

Kawasaki, Noritaka; Asada, Rie; Saito, Atsushi; Kanemoto, Soshi; Imaizumi, Kazunori

2012-01-01

Adipose tissue plays a central role in maintaining metabolic homeostasis under normal conditions. Metabolic diseases such as obesity and type 2 diabetes are often accompanied by chronic inflammation and adipose tissue dysfunction. In this study, we observed that endoplasmic reticulum (ER) stress and the inflammatory response occurred in adipose tissue of mice fed a high-fat diet for a period of 16 weeks. After 16 weeks of feeding, ER stress markers increased and chronic inflammation occurred in adipose tissue. We found that ER stress is induced by free fatty acid (FFA)-mediated reactive oxygen species (ROS) generation and up-regulated gene expression of inflammatory cytokines in 3T3-L1 adipocytes. Oral administration to obese mice of chemical chaperons, which alleviate ER stress, improved chronic inflammation in adipose tissue, followed by the suppression of increased body weight and improved insulin signaling. These results indicate that ER stress plays important pathophysiological roles in obesity-induced adipose tissue dysfunction.

Eat it right: ER-phagy and recovER-phagy.

PubMed

Loi, Marisa; Fregno, Ilaria; Guerra, Concetta; Molinari, Maurizio

2018-05-25

The endoplasmic reticulum (ER) is the site of protein, lipid, phospholipid, steroid and oligosaccharide synthesis and modification, calcium ion storage, and detoxification of endogenous and exogenous products. Its volume (and activity) must be maintained under normal growth conditions, must be expanded in a controlled manner on activation of ER stress programs and must be reduced to pre-stress size during the recovery phase that follows ER stress termination. ER-phagy is the constitutive or regulated fragmentation and delivery of ER fragments to lysosomal compartments for clearance. It gives essential contribution to the maintenance of cellular homeostasis, proteostasis, lipidostasis and oligosaccharidostasis (i.e. the capacity to produce the proteome, lipidome and oligosaccharidome in appropriate quality and quantity). ER turnover is activated on ER stress, nutrient deprivation, accumulation of misfolded polypeptides, pathogen attack and by activators of macroautophagy. The selectivity of these poorly characterized catabolic pathways is ensured by proteins displayed at the limiting membrane of the ER subdomain to be removed from cells. These proteins are defined as ER-phagy receptors and engage the cytosolic macroautophagy machinery via specific modules that associate with ubiquitin-like, cytosolic proteins of the Atg8/LC3/GABARAP family. In this review, we give an overview on selective ER turnover and on the yeast and mammalian ER-phagy receptors identified so far. © 2018 The Author(s).

Tauroursodeoxycholic acid (TUDCA) alleviates endoplasmic reticulum stress of nuclear donor cells under serum starvation.

PubMed

Zhang, Ying; Qu, Pengxiang; Ma, Xiaonan; Qiao, Fang; Ma, Yefei; Qing, Suzhu; Zhang, Yong; Wang, Yongsheng; Cui, Wei

2018-01-01

Serum starvation is a routine protocol for synchronizing nuclear donor cells to G0/G1 phase during somatic cell nuclear transfer (SCNT). However, abrupt serum deprivation can cause serious stress to the cells cultured in vitro, which might result in endoplasmic reticulum (ER) stress, chromosome damage, and finally reduce the success rate of SCNT. In the present study, the effects of tauroursodeoxycholic acid (TUDCA), an effective ER stress-relieving drug, on the nuclear donor cells under serum deprivation condition as well as following SCNT procedures were first assessed in the bovine. The results showed that TUDCA significantly reduced ER stress and cell apoptosis in those nuclear donor cells. Moreover, it significantly decreased the expression of Hdac1 and Dnmt1, and increased the level of H3K9 acetylation in nuclear donor cells compared with control group. SCNT reconstructed embryos cloned from TUDCA-treated donor cells showed significantly higher fusion, cleavage, blastocyst formation rate, total cell number in day 7 blastocysts, and lower apoptotic index than that from control group. In addition, the expression of Hdac1, Dnmt1 and Bax was significantly lower in blastocysts derived from TUDCA-treated donor cells than that from control group. In conclusion, TUDCA significantly reduced the ER stress of nuclear donor cells under serum starvation condition, and significantly improved the developmental competence of following SCNT reconstructed embryos when these TUDCA-treated cells were used as the nuclear donors.

Neuroprotective Effects of Protein Tyrosine Phosphatase 1B Inhibition against ER Stress-Induced Toxicity

PubMed Central

Jeon, Yu-Mi; Lee, Shinrye; Kim, Seyeon; Kwon, Younghwi; Kim, Kiyoung; Chung, Chang Geon; Lee, Seongsoo; Lee, Sung Bae; Kim, Hyung-Jun

2017-01-01

Several lines of evidence suggest that endoplasmic reticulum (ER) stress plays a critical role in the pathogenesis of many neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis. Protein tyrosine phosphatase 1B (PTP1B) is known to regulate the ER stress signaling pathway, but its role in neuronal systems in terms of ER stress remains largely unknown. Here, we showed that rotenone-induced toxicity in human neuroblastoma cell lines and mouse primary cortical neurons was ameliorated by PTP1B inhibition. Moreover, the increase in the level of ER stress markers (eIF2α phosphorylation and PERK phosphorylation) induced by rotenone treatment was obviously suppressed by concomitant PTP1B inhibition. However, the rotenone-induced production of reactive oxygen species (ROS) was not affected by PTP1B inhibition, suggesting that the neuroprotective effect of the PTP1B inhibitor is not associated with ROS production. Moreover, we found that MG132-induced toxicity involving proteasome inhibition was also ameliorated by PTP1B inhibition in a human neuroblastoma cell line and mouse primary cortical neurons. Consistently, downregulation of the PTP1B homologue gene in Drosophila mitigated rotenone- and MG132-induced toxicity. Taken together, these findings indicate that PTP1B inhibition may represent a novel therapeutic approach for ER stress-mediated neurodegenerative diseases. PMID:28359145

AAV delivery of GRP78/BiP promotes adaptation of human RPE cell to ER stress.

PubMed

Ghaderi, Shima; Ahmadian, Shahin; Soheili, Zahra-Soheila; Ahmadieh, Hamid; Samiei, Shahram; Kheitan, Samira; Pirmardan, Ehsan R

2018-02-01

Adeno associated virus (AAV)-mediated gene delivery of GRP78 (78 kDa glucose-regulated protein) attenuates the condition of endoplasmic reticulum (ER) stress and prevents apoptotic loss of photoreceptors in Retinitis pigmentosa (RP) rats. In the current study we overexpressed Grp78 with the help of AAV-2 in primary human retinal pigmented epithelium (hRPE) cell cultures and examined its effect on cell response to ER stress. The purpose of this work was studying potential stimulating effect of GRP78 on adaptation/pro-survival of hRPE cells under ER stress, as an in vitro model for RPE degeneration. To investigate the effect of Grp78 overexpression on unfolded protein response (UPR) markers under ER stress, hRPE primary cultures were transduced by recombinant virus rAAV/Grp78, and treated with ER stressor drug, tunicamycin. Expression changes of four UPR markers including GRP78, PERK, ATF6α, and GADD153/CHOP, were assessed by real-time PCR and western blotting. We found that GRP78 has a great contribution in modulation of UPR markers to favor adaptive response in ER-stressed hRPE cells. In fact, GRP78 overexpression affected adaptation and apoptotic phases of early UPR, through enhancement of two master regulators/ER stress sensors (PERK and ATF6α) and down-regulation of a key pro-apoptotic cascade activator (GADD153/CHOP). Together these findings demonstrate the promoting effect of GRP78 on adaptation/pro-survival of hRPE cells under ER stress. This protein with anti-apoptotic actions in the early UPR and important role in cell fate regulation, can be recruited as a useful candidate for future investigations of RPE degenerative diseases. © 2017 Wiley Periodicals, Inc.

Artemisinin dimer anti-cancer activity correlates with heme-catalyzed ROS generation and ER stress induction

PubMed Central

Stockwin, Luke H.; Han, Bingnan; Yu, Sherry X.; Hollingshead, Melinda G.; ElSohly, Mahmoud A.; Gul, Waseem; Slade, Desmond; Galal, Ahmed M.; Newton, Dianne L.

2009-01-01

Analogs of the malaria therapeutic, artemisinin, possess in vitro and in vivo anti-cancer activity. In this study, two dimeric artemisinins (NSC724910 and 735847) were studied to determine their mechanism of action. Dimers were >1000 fold more active than monomer and treatment was associated with increased reactive oxygen species (ROS) and apoptosis induction. Dimer activity was inhibited by the anti-oxidant L-NAC, the iron chelator desferroxamine, and exogenous hemin. Similarly, induction of heme oxygenase (HMOX) with CoPPIX inhibited activity while inhibition of HMOX with SnPPIX enhanced it. These results emphasize the importance of iron, heme and ROS in activity. Microarray analysis of dimer treated cells identified DNA damage; iron/heme and cysteine/methionine metabolism, antioxidant response, and endoplasmic reticulum (ER) stress as affected pathways. Detection of an ER-stress response was relevant because in malaria, artemisinin inhibits pfATP6, the plasmodium orthologue of mammalian ER-resident SERCA Ca2+-ATPases. A comparative study of NSC735847 with thapsigargin, a specific SERCA inhibitor and ER-stress inducer showed similar behavior in terms of transcriptomic changes, induction of endogenous SERCA and ER calcium mobilization. However, thapsigargin had little effect on ROS production, modulated different ER-stress proteins and had greater potency against purified SERCA1. Furthermore, an inactive derivative of NSC735847 that lacked the endoperoxide had identical inhibitory activity against purified SERCA1, suggesting that direct inhibition of SERCA has little inference on overall cytotoxicity. In summary, these data implicate indirect ER-stress induction as a central mechanism of artemisinin dimer activity. PMID:19533749

ER stress upregulated PGE2/IFNγ-induced IL-6 expression and down-regulated iNOS expression in glial cells

NASA Astrophysics Data System (ADS)

Hosoi, Toru; Honda, Miya; Oba, Tatsuya; Ozawa, Koichiro

2013-12-01

The disruption of endoplasmic reticulum (ER) function can lead to neurodegenerative disorders, in which inflammation has also been implicated. We investigated the possible correlation between ER stress and immune function using glial cells. We demonstrated that ER stress synergistically enhanced prostaglandin (PG) E2 + interferon (IFN) γ-induced interleukin (IL)-6 production. This effect was mediated through cAMP. Immune-activated glial cells produced inducible nitric oxide synthase (iNOS). Interestingly, ER stress inhibited PGE2 + IFNγ-induced iNOS expression. Similar results were obtained when cells were treated with dbcAMP + IFNγ. Thus, cAMP has a dual effect on immune reactions; cAMP up-regulated IL-6 expression, but down-regulated iNOS expression under ER stress. Therefore, our results suggest a link between ER stress and immune reactions in neurodegenerative diseases.

ER stress and genomic instability induced by gamma radiation in mice primary cultured glial cells.

PubMed

Chatterjee, Jit; Nairy, Rajesha K; Langhnoja, Jaldeep; Tripathi, Ashutosh; Patil, Rajashekhar K; Pillai, Prakash P; Mustak, Mohammed S

2018-06-01

Ionizing radiation induces various pathophysiological conditions by altering central nervous system (CNS) homeostasis, leading to neurodegenerative diseases. However, the potential effect of ionizing radiation response on cellular physiology in glial cells is unclear. In the present study, micronucleus test, comet assay, and RT-PCR were performed to investigate the potential effect of gamma radiation in cultured oligodendrocytes and astrocytes with respect to genomic instability, Endoplasmic Reticulum (ER) stress, and inflammation. Further, we studied the effect of alteration in ER stress specific gene expression in cortex post whole body radiation in mice. Results showed that exposure of gamma radiation of 2Gy in-vitro cultured astrocytes and oligodendrocytes and 7Gy in-vivo induced ER stress and Inflammation along with profuse DNA damage and Chromosomal abnormality. Additionally, we observed downregulation of myelin basic protein levels in cultured oligodendrocytes exposed to radiation. The present data suggests that ER stress and pro inflammatory cytokines serve as the major players in inducing glial cell dysfunction post gamma irradiation along with induction of genomic instability. Taken together, these results indicate that ER stress, DNA damage, and inflammatory pathways may be critical events leading to glial cell dysfunction and subsequent cell death following exposure to ionizing radiation.

Cadmium-induced teratogenicity: Association with ROS-mediated endoplasmic reticulum stress in placenta

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Zhen; Wang, Hua; Xu, Zhong Mei

The placenta is essential for sustaining the growth of the fetus. An increased endoplasmic reticulum (ER) stress has been associated with the impaired placental and fetal development. Cadmium (Cd) is a potent teratogen that caused fetal malformation and growth restriction. The present study investigated the effects of maternal Cd exposure on placental and fetal development. The pregnant mice were intraperitoneally injected with CdCl{sub 2} (4.5 mg/kg) on gestational day 9. As expected, maternal Cd exposure during early limb development significantly increased the incidences of forelimb ectrodactyly in fetuses. An obvious impairment in the labyrinth, a highly developed tissue of bloodmore » vessels, was observed in placenta of mice treated with CdCl{sub 2}. In addition, maternal Cd exposure markedly repressed cell proliferation and increased apoptosis in placenta. An additional experiment showed that maternal Cd exposure significantly upregulated the expression of GRP78, an ER chaperone. Moreover, maternal Cd exposure induced the phosphorylation of placental eIF2α, a downstream molecule of PERK signaling. In addition, maternal Cd exposure significantly increased the level of placental CHOP, another target of PERK signaling, indicating that the unfolded protein response (UPR) signaling was activated in placenta of mice treated with CdCl{sub 2}. Interestingly, alpha-phenyl-N-t-butylnitrone, a free radical spin-trapping agent, significantly alleviated Cd-induced placental ER stress and UPR. Taken together, these results suggest that reactive oxygen species (ROS)-mediated ER stress might be involved in Cd-induced impairment on placental and fetal development. Antioxidants may be used as pharmacological agents to protect against Cd-induced fetal malformation and growth restriction. -- Highlights: ► Cd induces fetal malformation and growth restriction. ► Cd induced placental ER stress and UPR. ► PBN alleviates Cd-induced ER stress and UPR in placenta. ► ROS

Pharmacological reduction of ER stress protects against TDP-43 neuronal toxicity in vivo.

PubMed

Vaccaro, Alexandra; Patten, Shunmoogum A; Aggad, Dina; Julien, Carl; Maios, Claudia; Kabashi, Edor; Drapeau, Pierre; Parker, J Alex

2013-07-01

C. elegans and D. rerio expressing mutant TAR DNA Binding Protein 43 (TDP-43) are powerful in vivo animal models for the genetics and pharmacology of amyotrophic lateral sclerosis (ALS). Using these small-animal models of ALS, we previously identified methylene blue (MB) as a potent suppressor of TDP-43 toxicity. Consequently here we investigated how MB might exert its neuroprotective properties and found that it acts through reduction of the endoplasmic reticulum (ER) stress response. We tested other compounds known to be active in the ER unfolded protein response in worms and zebrafish expressing mutant human TDP-43 (mTDP-43). We identified three compounds: salubrinal, guanabenz and a new structurally related compound phenazine, which also reduced paralysis, neurodegeneration and oxidative stress in our mTDP-43 models. Using C. elegans genetics, we showed that all four compounds act as potent suppressors of mTDP-43 toxicity through reduction of the ER stress response. Interestingly, these compounds operate through different branches of the ER unfolded protein pathway to achieve a common neuroprotective action. Our results indicate that protein-folding homeostasis in the ER is an important target for therapeutic development in ALS and other TDP-43-related neurodegenerative diseases. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

New insights on the functional role of URG7 in the cellular response to ER stress.

PubMed

Armentano, Maria Francesca; Caterino, Marianna; Miglionico, Rocchina; Ostuni, Angela; Pace, Maria Carmela; Cozzolino, Flora; Monti, Maria; Milella, Luigi; Carmosino, Monica; Pucci, Piero; Bisaccia, Faustino

2018-04-28

Up-regulated Gene clone 7 (URG7) is an ER resident protein, whose expression is up-regulated in the presence of hepatitis B virus X antigen (HBxAg) during HBV infection. In virus-infected hepatocytes, URG7 shows an anti-apoptotic activity due to the PI3K/AKT signalling activation, does not seem to have tumorigenic properties, but it appears to promote the development and progression of fibrosis. However, the molecular mechanisms underlying URG7 activity remain largely unknown. To shed light on URG7 activity, we first analysed its interactome in HepG2 transfected cells: this analysis suggests that URG7 could have a role in affecting protein synthesis, folding and promoting proteins degradation. Moreover, keeping into account its subcellular localisation in the ER and that several viral infections give rise to ER stress, a panel of experiments was performed to evaluate a putative role of URG7 in ER stress. Our main results demonstrate that in ER-stressed cells URG7 is able to modulate the expression of Unfolded Protein Response (UPR) markers towards survival outcomes, up-regulating GRP78 protein and down-regulating the pro-apoptotic protein CHOP. Furthermore, URG7 reduces the ER stress by decreasing the amount of unfolded proteins, by increasing both the total protein ubiquitination and the AKT activation and reducing Caspase 3 activation. All together these data suggest that URG7 plays a pivotal role as a reliever of ER stress-induced apoptosis. This is the first characterisation of URG7 activity under ER stress conditions. The results presented here will help to hypothesise new strategies to counteract the antiapoptotic activity of URG7 in the context of the viral infection. © 2018 Société Française des Microscopies and Société de Biologie Cellulaire de France. Published by John Wiley & Sons Ltd.

Structure-activity relationship of piperine and its synthetic amide analogs for therapeutic potential to prevent experimentally induced ER stress in vitro.

PubMed

Hammad, Ayat S; Ravindran, Sreenithya; Khalil, Ashraf; Munusamy, Shankar

2017-05-01

Endoplasmic reticulum (ER) is the key organelle involved in protein folding and maturation. Emerging studies implicate the role of ER stress in the development of chronic kidney disease. Thus, there is an urgent need for compounds that could ameliorate ER stress and prevent CKD. Piperine and its analogs have been reported to exhibit multiple pharmacological activities; however, their efficacy against ER stress in kidney cells has not been studied yet. Hence, the goal of this study was to synthesize amide-substituted piperine analogs and screen them for pharmacological activity to relieve ER stress using an in vitro model of tunicamycin-induced ER stress using normal rat kidney (NRK-52E) cells. Five amide-substituted piperine analogs were synthesized and their chemical structures were elucidated by pertinent spectroscopic techniques. An in vitro model of ER stress was developed using tunicamycin, and the compounds of interest were screened for their effect on cell viability, and the expression of ER chaperone GRP78, the pro-apoptotic ER stress marker CHOP, and apoptotic caspases 3 and 12 (via western blotting). Our findings indicate that exposure to tunicamycin (0.5 μg/mL) for 2 h induces the expression of GRP78 and CHOP, and apoptotic markers (caspase-3 and caspase-12) and causes a significant reduction in renal cell viability. Pre-treatment of cells with piperine and its cyclohexylamino analog decreased the tunicamycin-induced upregulation of GRP78 and CHOP and cell death. Taken together, our findings demonstrate that piperine and its analogs differentially regulate ER stress, and thus represent potential therapeutic agents to treat ER stress-related renal disorders. Graphical Abstract Piperine (PIP) reduces the expression of ER stress markers (GRP78 and CHOP) induced by pathologic stimuli and consequently decreases the activation of apoptotic caspase-12 and caspase-3; all of which contributes to its chemical chaperone and cytoprotective properties to protect

Insulin Protects Hepatic Lipotoxicity by Regulating ER Stress through the PI3K/Akt/p53 Involved Pathway Independently of Autophagy Inhibition.

PubMed

Ning, Hua; Sun, Zongxiang; Liu, Yunyun; Liu, Lei; Hao, Liuyi; Ye, Yaxin; Feng, Rennan; Li, Jie; Li, Ying; Chu, Xia; Li, Songtao; Sun, Changhao

2016-04-19

The detrimental role of hepatic lipotoxicity has been well-implicated in the pathogenesis of NAFLD. Previously, we reported that inhibiting autophagy aggravated saturated fatty acid (SFA)-induced hepatotoxicity. Insulin, a physiological inhibitor of autophagy, is commonly increased within NAFLD mainly caused by insulin resistance. We therefore hypothesized that insulin augments the sensitivity of hepatocyte to SFA-induced lipotoxicity. The present study was conducted via employing human and mouse hepatocytes, which were exposed to SFAs, insulin, or their combination. Unexpectedly, our results indicated that insulin protected hepatocytes against SFA-induced lipotoxicity, based on the LDH, MTT, and nuclear morphological measurements, and the detection from cleaved-Parp-1 and -caspase-3 expressions. We subsequently clarified that insulin led to a rapid and short-period inhibition of autophagy, which was gradually recovered after 1 h incubation in hepatocytes, and such extent of inhibition was insufficient to aggravate SFA-induced lipotoxicity. The mechanistic study revealed that insulin-induced alleviation of ER stress contributed to its hepatoprotective role. Pre-treating hepatocytes with insulin significantly stimulated phosphorylated-Akt and reversed SFA-induced up-regulation of p53. Chemical inhibition of p53 by pifithrin-α robustly prevented palmitate-induced cell death. The PI3K/Akt pathway blockade by its special antagonist abolished the protective role of insulin against SFA-induced lipotoxicity and p53 up-regulation. Furthermore, we observed that insulin promoted intracellular TG deposits in hepatocytes in the present of palmitate. However, blocking TG accumulation via genetically silencing DGAT-2 did not prevent insulin-protected lipotoxicity. Our study demonstrated that insulin strongly protected against SFA-induced lipotoxicity in hepatocytes mechanistically through alleviating ER stress via a PI3K/Akt/p53 involved pathway but independently from autophagy.

Aging induced endoplasmic reticulum stress alters sleep and sleep homeostasis.

PubMed

Brown, Marishka K; Chan, May T; Zimmerman, John E; Pack, Allan I; Jackson, Nicholas E; Naidoo, Nirinjini

2014-06-01

Alterations in the quality, quantity, and architecture of baseline and recovery sleep have been shown to occur during aging. Sleep deprivation induces endoplasmic reticular (ER) stress and upregulates a protective signaling pathway termed the unfolded protein response. The effectiveness of the adaptive unfolded protein response is diminished by age. Previously, we showed that endogenous chaperone levels altered recovery sleep in Drosophila melanogaster. We now report that acute administration of the chemical chaperone sodium 4-phenylbutyrate (PBA) reduces ER stress and ameliorates age-associated sleep changes in Drosophila. PBA consolidates both baseline and recovery sleep in aging flies. The behavioral modifications of PBA are linked to its suppression of ER stress. PBA decreased splicing of X-box binding protein 1 and upregulation of phosphorylated elongation initiation factor 2 α, in flies that were subjected to sleep deprivation. We also demonstrate that directly activating ER stress in young flies fragments baseline sleep and alters recovery sleep. Alleviating prolonged or sustained ER stress during aging contributes to sleep consolidation and improves recovery sleep or sleep debt discharge. Copyright © 2014 Elsevier Inc. All rights reserved.

Inhibition of ER stress and unfolding protein response pathways causes skeletal muscle wasting during cancer cachexia.

PubMed

Bohnert, Kyle R; Gallot, Yann S; Sato, Shuichi; Xiong, Guangyan; Hindi, Sajedah M; Kumar, Ashok

2016-09-01

Cachexia is a devastating syndrome that causes morbidity and mortality in a large number of patients with cancer. However, the mechanisms of cancer cachexia remain poorly understood. Accumulation of misfolded proteins in the endoplasmic reticulum (ER) causes stress. The ER responds to this stress through activating certain pathways commonly known as the unfolding protein response (UPR). The main function of UPR is to restore homeostasis, but excessive or prolonged activation of UPR can lead to pathologic conditions. In this study, we examined the role of ER stress and UPR in regulation of skeletal muscle mass in naïve conditions and during cancer cachexia. Our results demonstrate that multiple markers of ER stress are highly activated in skeletal muscle of Lewis lung carcinoma (LLC) and Apc(Min/+) mouse models of cancer cachexia. Treatment of mice with 4-phenylbutyrate (4-PBA), a chemical chaperon and a potent inhibitor of ER stress, significantly reduced skeletal muscle strength and mass in both control and LLC-bearing mice. Blocking the UPR also increased the proportion of fast-type fibers in soleus muscle of both control and LLC-bearing mice. Inhibition of UPR reduced the activity of Akt/mTOR pathway and increased the expression of the components of the ubiquitin-proteasome system and autophagy in LLC-bearing mice. Moreover, we found that the inhibition of UPR causes severe atrophy in cultured myotubes. Our study provides initial evidence that ER stress and UPR pathways are essential for maintaining skeletal muscle mass and strength and for protection against cancer cachexia.-Bohnert, K. R., Gallot, Y. S., Sato, S., Xiong, G., Hindi, S. M., Kumar, A. Inhibition of ER stress and unfolding protein response pathways causes skeletal muscle wasting during cancer cachexia. © FASEB.

High-intensity training reduces intermittent hypoxia-induced ER stress and myocardial infarct size.

PubMed

Bourdier, Guillaume; Flore, Patrice; Sanchez, Hervé; Pepin, Jean-Louis; Belaidi, Elise; Arnaud, Claire

2016-01-15

Chronic intermittent hypoxia (IH) is described as the major detrimental factor leading to cardiovascular morbimortality in obstructive sleep apnea (OSA) patients. OSA patients exhibit increased infarct size after a myocardial event, and previous animal studies have shown that chronic IH could be the main mechanism. Endoplasmic reticulum (ER) stress plays a major role in the pathophysiology of cardiovascular disease. High-intensity training (HIT) exerts beneficial effects on the cardiovascular system. Thus, we hypothesized that HIT could prevent IH-induced ER stress and the increase in infarct size. Male Wistar rats were exposed to 21 days of IH (21-5% fraction of inspired O2, 60-s cycle, 8 h/day) or normoxia. After 1 wk of IH alone, rats were submitted daily to both IH and HIT (2 × 24 min, 15-30m/min). Rat hearts were either rapidly frozen to evaluate ER stress by Western blot analysis or submitted to an ischemia-reperfusion protocol ex vivo (30 min of global ischemia/120 min of reperfusion). IH induced cardiac proapoptotic ER stress, characterized by increased expression of glucose-regulated protein kinase 78, phosphorylated protein kinase-like ER kinase, activating transcription factor 4, and C/EBP homologous protein. IH-induced myocardial apoptosis was confirmed by increased expression of cleaved caspase-3. These IH-associated proapoptotic alterations were associated with a significant increase in infarct size (35.4 ± 3.2% vs. 22.7 ± 1.7% of ventricles in IH + sedenary and normoxia + sedentary groups, respectively, P < 0.05). HIT prevented both the IH-induced proapoptotic ER stress and increased myocardial infarct size (28.8 ± 3.9% and 21.0 ± 5.1% in IH + HIT and normoxia + HIT groups, respectively, P = 0.28). In conclusion, these findings suggest that HIT could represent a preventive strategy to limit IH-induced myocardial ischemia-reperfusion damages in OSA patients. Copyright © 2016 the American Physiological Society.

Innate Sensing of Influenza A Virus Hemagglutinin Glycoproteins by the Host Endoplasmic Reticulum (ER) Stress Pathway Triggers a Potent Antiviral Response via ER-Associated Protein Degradation.

PubMed

Frabutt, Dylan A; Wang, Bin; Riaz, Sana; Schwartz, Richard C; Zheng, Yong-Hui

2018-01-01

Innate immunity provides an immediate defense against infection after host cells sense danger signals from microbes. Endoplasmic reticulum (ER) stress arises from accumulation of misfolded/unfolded proteins when protein load overwhelms the ER folding capacity, which activates the unfolded protein response (UPR) to restore ER homeostasis. Here, we show that a mechanism for antiviral innate immunity is triggered after the ER stress pathway senses viral glycoproteins. When hemagglutinin (HA) glycoproteins from influenza A virus (IAV) are expressed in cells, ER stress is induced, resulting in rapid HA degradation via proteasomes. The ER-associated protein degradation (ERAD) pathway, an important UPR function for destruction of aberrant proteins, mediates HA degradation. Three class I α-mannosidases were identified to play a critical role in the degradation process, including EDEM1, EDEM2, and ERManI. HA degradation requires either ERManI enzymatic activity or EDEM1/EDEM2 enzymatic activity when ERManI is not expressed, indicating that demannosylation is a critical step for HA degradation. Silencing of EDEM1, EDEM2, and ERManI strongly increases HA expression and promotes IAV replication. Thus, the ER stress pathway senses influenza HA as "nonself" or misfolded protein and sorts HA to ERAD for degradation, resulting in inhibition of IAV replication. IMPORTANCE Viral nucleic acids are recognized as important inducers of innate antiviral immune responses that are sensed by multiple classes of sensors, but other inducers and sensors of viral innate immunity need to be identified and characterized. Here, we used IAV to investigate how host innate immunity is activated. We found that IAV HA glycoproteins induce ER stress, resulting in HA degradation via ERAD and consequent inhibition of IAV replication. In addition, we have identified three class I α-mannosidases, EDEM1, EDEM2, and ERManI, which play a critical role in initiating HA degradation. Knockdown of these proteins

Curcumin abates hypoxia-induced oxidative stress based-ER stress-mediated cell death in mouse hippocampal cells (HT22) by controlling Prdx6 and NF-κB regulation

PubMed Central

Chhunchha, Bhavana; Fatma, Nigar; Kubo, Eri; Rai, Prerana; Singh, Sanjay P.

2013-01-01

Oxidative stress and endoplasmic reticulum (ER) stress are emerging as crucial events in the etiopathology of many neurodegenerative diseases. While the neuroprotective contributions of the dietary compound curcumin has been recognized, the molecular mechanisms underlying curcumin's neuroprotection under oxidative and ER stresses remains elusive. Herein, we show that curcumin protects HT22 from oxidative and ER stresses evoked by the hypoxia (1% O2 or CoCl2 treatment) by enhancing peroxiredoxin 6 (Prdx6) expression. Cells exposed to CoCl2 displayed reduced expression of Prdx6 with higher reactive oxygen species (ROS) expression and activation of NF-κB with IκB phosphorylation. When NF-κB activity was blocked by using SN50, an inhibitor of NF-κB, or cells treated with curcumin, the repression of Prdx6 expression was restored, suggesting the involvement of NF-κB in modulating Prdx6 expression. These cells were enriched with an accumulation of ER stress proteins, C/EBP homologous protein (CHOP), GRP/78, and calreticulin, and had activated states of caspases 12, 9, and 3. Reinforced expression of Prdx6 in HT22 cells by curcumin reestablished survival signaling by reducing propagation of ROS and blunting ER stress signaling. Intriguingly, knockdown of Prdx6 by antisense revealed that loss of Prdx6 contributed to cell death by sustaining enhanced levels of ER stress-responsive proapoptotic proteins, which was due to elevated ROS production, suggesting that Prdx6 deficiency is a cause of initiation of ROS-mediated ER stress-induced apoptosis. We propose that using curcumin to reinforce the naturally occurring Prdx6 expression and attenuate ROS-based ER stress and NF-κB-mediated aberrant signaling improves cell survival and may provide an avenue to treat and/or postpone diseases associated with ROS or ER stress. PMID:23364261

Insights on the involvement of (-)-epigallocatechin gallate in ER stress-mediated apoptosis in age-related macular degeneration.

PubMed

Karthikeyan, Bose; Harini, Lakshminarasimhan; Krishnakumar, Vaithilingam; Kannan, Velu Rajesh; Sundar, Krishnan; Kathiresan, Thandavarayan

2017-01-01

Endoplasmic reticulum (ER) stress-mediated apoptosis is a well-known factor in the pathogenesis of age-related macular degeneration (AMD). ER stress leads to accumulation of misfolded proteins, which in turn activates unfolded protein response (UPR) of the cell for its survival. The prolonged UPR of ER stress promotes cell death; however, the transition between adaptation and ER stress-induced apoptosis has not been clearly understood. Hence, the present study investigates the regulatory effect of (-)-epigallocatechin gallate (EGCG) on ER stress-induced by hydrogen peroxide (H 2 O 2 ) and disturbance of calcium homeostasis by thapsigargin (TG) in mouse retinal pigment epithelial (MRPE) cells. The oxidant molecules influenced MRPE cells showed an increased level of intracellular calcium [Ca 2+ ] i in ER and transferred to mitochondria through ER-mitochondrial tether site then increased ROS production. EGCG restores [Ca 2+ ] i homeostasis by decreasing ROS production through inhibition of prohibitin1 which regulate ER-mitochondrial tether site and inhibit apoptosis. Effect of EGCG on ER stress-mediated apoptosis was elucidated by exploring the UPR signalling pathways. EGCG downregulated GRP78, CHOP, PERK, ERO1α, IRE1α, cleaved PARP, cleaved caspase 3, caspase 12 and upregulated expression of calnexinin MRPE cells. In addition to this, inhibition of apoptosis by EGCG was also confirmed with expression of proteins Akt, PTEN and GSK3β. MRPE cells with EGCG upregulates phosphorylation of Akt at ser473 and phospho ser380 of PTEN, but phosphorylation at ser9 of GSK3β was inhibited. Further, constitutively active (myristoylated) CA-Akt transfected in MRPE cells had an increased Akt activity in EGCG influenced cells. These findings strongly suggest that antioxidant molecules inhibit cell death through the proper balancing of [Ca 2+ ] i and ROS production in order to maintain UPR of ER in MRPE cells. Thus, modulation of UPR signalling may provide a potential target for

Liver-specific loss of Perilipin 2 alleviates diet-induced hepatic steatosis, inflammation, and fibrosis

PubMed Central

Najt, Charles P.; Senthivinayagam, Subramanian; Aljazi, Mohammad B.; Fader, Kelly A.; Olenic, Sandra D.; Brock, Julienne R. L.; Lydic, Todd A.; Jones, A. Daniel

2016-01-01

Hepatic inflammation and fibrosis are key elements in the pathogenesis of nonalcoholic steatohepatitis (NASH), a progressive liver disease initiated by excess hepatic lipid accumulation. Lipid droplet protein Perilipin 2 (Plin2) alleviates dietary-induced hepatic steatosis when globally ablated; however, its role in the progression of NASH remains unknown. To investigate this further, we challenged Plin2 liver-specific knockout mice (designated L-KO) and their respective wild-type (WT) controls with a methionine-choline-deficient (MCD) diet for 15 days to induce a NASH phenotype of increased hepatic triglyceride levels through impaired phosphatidylcholine (PC) synthesis and very-low-density lipoprotein (VLDL) secretion. Results on liver weights, body weights, fat tissue mass, and histology in WT and L-KO mice fed the MCD diet revealed signs of hepatic steatosis, fibrosis, and inflammation; however, these effects were blunted in L-KO mice. In addition, levels of PC and VLDL were unchanged, and hepatic steatosis was reduced in L-KO mice fed the MCD diet, due in part to an increase in remodeling of PE to PC via the enzyme phosphatidylethanolamine N-methyltransferase (PEMT). These mice also exhibited decreased hepatic expression of proinflammatory markers cyclooxygenase 2, IL-6, TNF-α, IL-1β, and reduced expression of endoplasmic reticulum (ER) stress proteins C/EBP homologous protein and cleaved caspase-1. Taken together, these results suggest that Plin2 liver-specific ablation alleviates diet-induced hepatic steatosis and inflammation via a PEMT-mediated mechanism that involves compensatory changes in proteins involved in phospholipid remodeling, inflammation, and ER stress that work to alleviate diet-induced NASH. Overall, these findings support a role for Plin2 as a target for NASH therapy. PMID:26968211

Glucose Regulation of Load‐Induced mTOR Signaling and ER Stress in Mammalian Heart

PubMed Central

Sen, Shiraj; Kundu, Bijoy K.; Wu, Henry Cheng‐Ju; Hashmi, S. Shahrukh; Guthrie, Patrick; Locke, Landon W.; Roy, R. Jack; Matherne, G. Paul; Berr, Stuart S.; Terwelp, Matthew; Scott, Brian; Carranza, Sylvia; Frazier, O. Howard; Glover, David K.; Dillmann, Wolfgang H.; Gambello, Michael J.; Entman, Mark L.; Taegtmeyer, Heinrich

2013-01-01

Background Changes in energy substrate metabolism are first responders to hemodynamic stress in the heart. We have previously shown that hexose‐6‐phosphate levels regulate mammalian target of rapamycin (mTOR) activation in response to insulin. We now tested the hypothesis that inotropic stimulation and increased afterload also regulate mTOR activation via glucose 6‐phosphate (G6P) accumulation. Methods and Results We subjected the working rat heart ex vivo to a high workload in the presence of different energy‐providing substrates including glucose, glucose analogues, and noncarbohydrate substrates. We observed an association between G6P accumulation, mTOR activation, endoplasmic reticulum (ER) stress, and impaired contractile function, all of which were prevented by pretreating animals with rapamycin (mTOR inhibition) or metformin (AMPK activation). The histone deacetylase inhibitor 4‐phenylbutyrate, which relieves ER stress, also improved contractile function. In contrast, adding the glucose analogue 2‐deoxy‐d‐glucose, which is phosphorylated but not further metabolized, to the perfusate resulted in mTOR activation and contractile dysfunction. Next we tested our hypothesis in vivo by transverse aortic constriction in mice. Using a micro‐PET system, we observed enhanced glucose tracer analog uptake and contractile dysfunction preceding dilatation of the left ventricle. In contrast, in hearts overexpressing SERCA2a, ER stress was reduced and contractile function was preserved with hypertrophy. Finally, we examined failing human hearts and found that mechanical unloading decreased G6P levels and ER stress markers. Conclusions We propose that glucose metabolic changes precede and regulate functional (and possibly also structural) remodeling of the heart. We implicate a critical role for G6P in load‐induced mTOR activation and ER stress. PMID:23686371

5-LO inhibition ameliorates palmitic acid-induced ER stress, oxidative stress and insulin resistance via AMPK activation in murine myotubes.

PubMed

Kwak, Hyun Jeong; Choi, Hye-Eun; Cheon, Hyae Gyeong

2017-07-10

Leukotriene B4 (LTB4) production via the 5-lipoxygenase (5-LO) pathway contributes to the development of insulin resistance in adipose and hepatic tissues, but the role of LTB4 in skeletal muscle is relatively unknown. Here, the authors investigated the role of LTB4 in C2C12 myotubes in palmitic acid (PA)-induced ER stress, inflammation and insulin resistance. PA (750 μM) evoked lipotoxicity (ER stress, oxidative stress, inflammation and insulin resistance) in association with LTB4 production. 5-LO inhibition reduced all the lipotoxic effects induced by PA. On the other hand, PA did not induce cysteinyl leukotrienes (CysLTs), which themselves had no effect on ER stress and inflammation. The beneficial effects of 5-LO suppression from PA-induced lipotoxicity were related with AMPK activation. In ob/ob mice, once daily oral administration of zileuton (50, 100 mg/kg) for 5 weeks improved insulin resistance, increased AMPK phosphorylation, and reduced LTB4 and ER stress marker expression in skeletal muscle. These results show that 5-LO inhibition by either zileuton or 5-LO siRNA protects C2C12 myotubes from PA-induced lipotoxicity, at least partly via AMPK activation, and suggest that the in vivo insulin-sensitizing effects of zileuton are in part attributable to its direct action on skeletal muscle via LTB4 downregulation followed by AMPK activation.

Genome-wide screen identifies a novel p97/CDC-48-dependent pathway regulating ER-stress-induced gene transcription.

PubMed

Marza, Esther; Taouji, Saïd; Barroso, Kim; Raymond, Anne-Aurélie; Guignard, Léo; Bonneu, Marc; Pallares-Lupon, Néstor; Dupuy, Jean-William; Fernandez-Zapico, Martin E; Rosenbaum, Jean; Palladino, Francesca; Dupuy, Denis; Chevet, Eric

2015-03-01

The accumulation of misfolded proteins in the endoplasmic reticulum (ER) activates the Unfolded Protein Response (UPR(ER)) to restore ER homeostasis. The AAA(+) ATPase p97/CDC-48 plays key roles in ER stress by promoting both ER protein degradation and transcription of UPR(ER) genes. Although the mechanisms associated with protein degradation are now well established, the molecular events involved in the regulation of gene transcription by p97/CDC-48 remain unclear. Using a reporter-based genome-wide RNAi screen in combination with quantitative proteomic analysis in Caenorhabditis elegans, we have identified RUVB-2, a AAA(+) ATPase, as a novel repressor of a subset of UPR(ER) genes. We show that degradation of RUVB-2 by CDC-48 enhances expression of ER stress response genes through an XBP1-dependent mechanism. The functional interplay between CDC-48 and RUVB-2 in controlling transcription of select UPR(ER) genes appears conserved in human cells. Together, these results describe a novel role for p97/CDC-48, whereby its role in protein degradation is integrated with its role in regulating expression of ER stress response genes. © 2015 The Authors.

β-Cell Dysfunction Due to Increased ER Stress in a Stem Cell Model of Wolfram Syndrome

PubMed Central

Shang, Linshan; Hua, Haiqing; Foo, Kylie; Martinez, Hector; Watanabe, Kazuhisa; Zimmer, Matthew; Kahler, David J.; Freeby, Matthew; Chung, Wendy; LeDuc, Charles; Goland, Robin; Leibel, Rudolph L.; Egli, Dieter

2014-01-01

Wolfram syndrome is an autosomal recessive disorder caused by mutations in WFS1 and is characterized by insulin-dependent diabetes mellitus, optic atrophy, and deafness. To investigate the cause of β-cell failure, we used induced pluripotent stem cells to create insulin-producing cells from individuals with Wolfram syndrome. WFS1-deficient β-cells showed increased levels of endoplasmic reticulum (ER) stress molecules and decreased insulin content. Upon exposure to experimental ER stress, Wolfram β-cells showed impaired insulin processing and failed to increase insulin secretion in response to glucose and other secretagogues. Importantly, 4-phenyl butyric acid, a chemical protein folding and trafficking chaperone, restored normal insulin synthesis and the ability to upregulate insulin secretion. These studies show that ER stress plays a central role in β-cell failure in Wolfram syndrome and indicate that chemical chaperones might have therapeutic relevance under conditions of ER stress in Wolfram syndrome and other forms of diabetes. PMID:24227685

Interaction between endoplasmic/sarcoplasmic reticulum stress (ER/SR stress), mitochondrial signaling and Ca(2+) regulation in airway smooth muscle (ASM).

PubMed

Delmotte, Philippe; Sieck, Gary C

2015-02-01

Airway inflammation is a key aspect of diseases such as asthma. Several inflammatory cytokines (e.g., TNFα and IL-13) increase cytosolic Ca(2+) ([Ca(2+)]cyt) responses to agonist stimulation and Ca(2+) sensitivity of force generation, thereby enhancing airway smooth muscle (ASM) contractility (hyper-reactive state). Inflammation also induces ASM proliferation and remodeling (synthetic state). In normal ASM, the transient elevation of [Ca(2+)]cyt induced by agonists leads to a transient increase in mitochondrial Ca(2+) ([Ca(2+)]mito) that may be important in matching ATP production with ATP consumption. In human ASM (hASM) exposed to TNFα and IL-13, the transient increase in [Ca(2+)]mito is blunted despite enhanced [Ca(2+)]cyt responses. We also found that TNFα and IL-13 induce reactive oxidant species (ROS) formation and endoplasmic/sarcoplasmic reticulum (ER/SR) stress (unfolded protein response) in hASM. ER/SR stress in hASM is associated with disruption of mitochondrial coupling with the ER/SR membrane, which relates to reduced mitofusin 2 (Mfn2) expression. Thus, in hASM it appears that TNFα and IL-13 result in ROS formation leading to ER/SR stress, reduced Mfn2 expression, disruption of mitochondrion-ER/SR coupling, decreased mitochondrial Ca(2+) buffering, mitochondrial fragmentation, and increased cell proliferation.

Curcumin induces ER stress-mediated apoptosis through selective generation of reactive oxygen species in cervical cancer cells.

PubMed

Kim, Boyun; Kim, Hee Seung; Jung, Eun-Ji; Lee, Jung Yun; K Tsang, Benjamin; Lim, Jeong Mook; Song, Yong Sang

2016-05-01

Prolonged accumulation of misfolded or unfolded proteins caused by cellular stress, including oxidative stress, induces endoplasmic reticulum stress, which then activates an unfolded protein response (UPR). ER stress is usually maintained at higher levels in cancer cells as compared to normal cells due to altered metabolism in cancer. Here, we investigated whether curcumin is ER stress-mediated apoptosis in cervical cancer cells, and ROS increased by curcumin are involved in the process as an upstream contributor. Curcumin inhibited proliferation of cervical cancer cells (C33A, CaSki, HeLa, and ME180) and induced apoptotic cell death. Curcumin activated ER-resident UPR sensors, such as PERK, IRE-1α, and ATF6, and their downstream-signaling proteins in cervical cancer cells, but not in normal epithelial cells and peripheral blood mononuclear cells (PBMCs). CHOP, a key factor involved in ER stress-mediated apoptosis, was also activated by curcumin. CHOP decreased the ratio of anti-apoptotic protein Bcl-2 to pro-apoptotic protein Bax expression, and subsequently increased the apoptotic population of cervical cancer cells. Furthermore, curcumin elevated levels of intracellular reactive oxygen species (ROS) in cervical cancer cells, but not in normal epithelial cells. Scavenging ROS resulted in inhibition of ER stress and partially restored cell viability in curcumin-treated cancer cells. Collectively, these observations show that curcumin promotes ER stress-mediated apoptosis in cervical cancer cells through increase of cell type-specific ROS generation. Therefore, modulation of these differential responses to curcumin between normal and cervical cancer cells could be an effective therapeutic strategy without adverse effects on normal cells. © 2015 Wiley Periodicals, Inc.

Calcium and ER stress mediate hepatic apoptosis after burn injury

PubMed Central

Gauglitz, Gerd G.; Song, Juquan; Kulp, Gabriela A.; Finnerty, Celeste C.; Cox, Robert A.; Barral, José M.; Herndon, David N.; Boehning, Darren

2009-01-01

Abstract A hallmark of the disease state following severe burn injury is decreased liver function, which results in gross metabolic derangements that compromise patient survival. The underlying mechanisms leading to hepatocyte dysfunction after burn are essentially unknown. The aim of the present study was to determine the underlying mechanisms leading to hepatocyte dysfunction and apoptosis after burn. Rats were randomized to either control (no burn) or burn (60% total body surface area burn) and sacrificed at various time‐points. Liver was either perfused to isolate primary rat hepatocytes, which were used for in vitro calcium imaging, or liver was harvested and processed for immunohistology, transmission electron microscopy, mitochondrial isolation, mass spectroscopy or Western blotting to determine the hepatic response to burn injury in vivo. We found that thermal injury leads to severely depleted endoplasmic reticulum (ER) calcium stores and consequent elevated cytosolic calcium concentrations in primary hepatocytes in vitro. Burn‐induced ER calcium depletion caused depressed hepatocyte responsiveness to signalling molecules that regulate hepatic homeostasis, such as vasopressin and the purinergic agonist ATP. In vivo, thermal injury resulted in activation of the ER stress response and major alterations in mitochondrial structure and function – effects which may be mediated by increased calcium release by inositol 1,4,5‐trisphosphate receptors. Our results reveal that thermal injury leads to dramatic hepatic disturbances in calcium homeostasis and resultant ER stress leading to mitochondrial abnormalities contributing to hepatic dysfunction and apoptosis after burn injury. PMID:20141609

Calorie-induced ER stress suppresses uroguanylin satiety signaling in diet-induced obesity.

PubMed

Kim, G W; Lin, J E; Snook, A E; Aing, A S; Merlino, D J; Li, P; Waldman, S A

2016-05-23

The uroguanylin-GUCY2C gut-brain axis has emerged as one component regulating feeding, energy homeostasis, body mass and metabolism. Here, we explore a role for this axis in mechanisms underlying diet-induced obesity (DIO). Intestinal uroguanylin expression and secretion, and hypothalamic GUCY2C expression and anorexigenic signaling, were quantified in mice on high-calorie diets for 14 weeks. The role of endoplasmic reticulum (ER) stress in suppressing uroguanylin in DIO was explored using tunicamycin, an inducer of ER stress, and tauroursodeoxycholic acid (TUDCA), a chemical chaperone that inhibits ER stress. The impact of consumed calories on uroguanylin expression was explored by dietary manipulation. The role of uroguanylin in mechanisms underlying obesity was examined using Camk2a-Cre-ER(T2)-Rosa-STOP(loxP/loxP)-Guca2b mice in which tamoxifen induces transgenic hormone expression in brain. DIO suppressed intestinal uroguanylin expression and eliminated its postprandial secretion into the circulation. DIO suppressed uroguanylin through ER stress, an effect mimicked by tunicamycin and blocked by TUDCA. Hormone suppression by DIO reflected consumed calories, rather than the pathophysiological milieu of obesity, as a diet high in calories from carbohydrates suppressed uroguanylin in lean mice, whereas calorie restriction restored uroguanylin in obese mice. However, hypothalamic GUCY2C, enriched in the arcuate nucleus, produced anorexigenic signals mediating satiety upon exogenous agonist administration, and DIO did not impair these responses. Uroguanylin replacement by transgenic expression in brain repaired the hormone insufficiency and reconstituted satiety responses opposing DIO and its associated comorbidities, including visceral adiposity, glucose intolerance and hepatic steatosis. These studies reveal a novel pathophysiological mechanism contributing to obesity in which calorie-induced suppression of intestinal uroguanylin impairs hypothalamic mechanisms

Disrupted autophagy after spinal cord injury is associated with ER stress and neuronal cell death

PubMed Central

Liu, S; Sarkar, C; Dinizo, M; Faden, A I; Koh, E Y; Lipinski, M M; Wu, J

2015-01-01

Autophagy is a catabolic mechanism facilitating degradation of cytoplasmic proteins and organelles in a lysosome-dependent manner. Autophagy flux is necessary for normal neuronal homeostasis and its dysfunction contributes to neuronal cell death in several neurodegenerative diseases. Elevated autophagy has been reported after spinal cord injury (SCI); however, its mechanism, cell type specificity and relationship to cell death are unknown. Using a rat model of contusive SCI, we observed accumulation of LC3-II-positive autophagosomes starting at posttrauma day 1. This was accompanied by a pronounced accumulation of autophagy substrate protein p62, indicating that early elevation of autophagy markers reflected disrupted autophagosome degradation. Levels of lysosomal protease cathepsin D and numbers of cathepsin-D-positive lysosomes were also decreased at this time, suggesting that lysosomal damage may contribute to the observed defect in autophagy flux. Normalization of p62 levels started by day 7 after SCI, and was associated with increased cathepsin D levels. At day 1 after SCI, accumulation of autophagosomes was pronounced in ventral horn motor neurons and dorsal column oligodendrocytes and microglia. In motor neurons, disruption of autophagy strongly correlated with evidence of endoplasmic reticulum (ER) stress. As autophagy is thought to protect against ER stress, its disruption after SCI could contribute to ER-stress-induced neuronal apoptosis. Consistently, motor neurons showing disrupted autophagy co-expressed ER-stress-associated initiator caspase 12 and cleaved executioner caspase 3. Together, these findings indicate that SCI causes lysosomal dysfunction that contributes to autophagy disruption and associated ER-stress-induced neuronal apoptosis. PMID:25569099

Palmitate-induced ER stress and inhibition of protein synthesis in cultured myotubes does not require Toll-like receptor 4.

PubMed

Perry, Ben D; Rahnert, Jill A; Xie, Yang; Zheng, Bin; Woodworth-Hobbs, Myra E; Price, S Russ

2018-01-01

Saturated fatty acids, such as palmitate, are elevated in metabolically dysfunctional conditions like type 2 diabetes mellitus. Palmitate has been shown to impair insulin sensitivity and suppress protein synthesis while upregulating proteolytic systems in skeletal muscle. Increased sarco/endoplasmic reticulum (ER) stress and subsequent activation of the unfolded protein response may contribute to the palmitate-induced impairment of muscle protein synthesis. In some cell types, ER stress occurs through activation of the Toll-like receptor 4 (TLR4). Given the link between ER stress and suppression of protein synthesis, we investigated whether palmitate induces markers of ER stress and protein synthesis by activating TLR4 in cultured mouse C2C12 myotubes. Myotubes were treated with vehicle, a TLR4-specific ligand (lipopolysaccharides), palmitate, or a combination of palmitate plus a TLR4-specific inhibitor (TAK-242). Inflammatory indicators of TLR4 activation (IL-6 and TNFα) and markers of ER stress were measured, and protein synthesis was assessed using puromycin incorporation. Palmitate substantially increased the levels of IL-6, TNF-α, CHOP, XBP1s, and ATF 4 mRNAs and augmented the levels of CHOP, XBP1s, phospho-PERK and phospho-eIF2α proteins. The TLR4 antagonist attenuated both acute palmitate and LPS-induced increases in IL-6 and TNFα, but did not reduce ER stress signaling with either 6 h or 24 h palmitate treatment. Similarly, treating myotubes with palmitate for 6 h caused a 43% decline in protein synthesis consistent with an increase in phospho-eIF2α, and the TLR4 antagonist did not alter these responses. These results suggest that palmitate does not induce ER stress through TLR4 in muscle, and that palmitate impairs protein synthesis in skeletal muscle in part by induction of ER stress.

Curcumin and Curcuma longa L. extract ameliorate lipid accumulation through the regulation of the endoplasmic reticulum redox and ER stress.

PubMed

Lee, Hwa-Young; Kim, Seung-Wook; Lee, Geum-Hwa; Choi, Min-Kyung; Chung, Han-Wool; Lee, Yong-Chul; Kim, Hyung-Ryong; Kwon, Ho Jeong; Chae, Han-Jung

2017-07-26

For this study, we examined the effects of curcumin against acute and chronic stress, paying specific attention to ROS. We also aimed to clarify the differences between acute and chronic stress conditions. We investigated the effects of curcumin against acute stress (once/1 day CCl 4 treatment) and chronic-stress (every other day/4week CCl 4 treatment). Compared with acute stress, in which the antioxidant system functioned properly and aspartate transaminase (AST) and ROS production increased, chronic stress increased AST, alanine aminotransferase (ALT), hepatic enzymes, and ROS more significantly, and the antioxidant system became impaired. We also found that ER-originated ROS accumulated in the chronic model, another difference between the two conditions. ER stress was induced consistently, and oxidative intra-ER protein folding status, representatively PDI, was impaired, especially in chronic stress. The PDI-associated client protein hepatic apoB accumulated with the PDI-binding status in chronic stress, and curcumin recovered the altered ER folding status, regulating ER stress and the resultant hepatic dyslipidemia. Throughout this study, curcumin and curcumin-rich Curcuma longa L. extract promoted recovery from CCl 4 -induced hepatic toxicity in both stress conditions. For both stress-associated hepatic dyslipidemia, curcumin and Curcuma longa L. extract might be recommendable to recover liver activity.

Ursodeoxycholic Acid Ameliorated Diabetic Nephropathy by Attenuating Hyperglycemia-Mediated Oxidative Stress.

PubMed

Cao, Aili; Wang, Li; Chen, Xia; Guo, Hengjiang; Chu, Shuang; Zhang, Xuemei; Peng, Wen

2016-08-01

Oxidative stress has a great role in diabetes and diabetes induced organ damage. Endoplasmic reticulum (ER) stress is involved in the onset of diabetic nephropathy. We hypothesize that ER stress inhibition could protect against kidney injury through anti-oxidative effects. To test whether block ER stress could attenuate oxidative stress and improve diabetic nephropathy in vivo and in vitro, the effect of ursodeoxycholic acid (UDCA), an ER stress inhibitor, on spontaneous diabetic nephropathy db/db mice, ER stress inducer or high glucose-triggered podocytes were studied. Mice were assigned to 3 groups (n=6 per group): control group (treated with vehicle), db/db group (treated with vehicle), and UDCA group (db/db mice treated with 40 mg/kg/d UDCA). After 8 weeks treatment, mice were sacrificed. Blood and kidneys were collected for the assessment of albumin/creatinine ratio, blood urea nitrogen (BUN), serum creatinine (SCr), insulin, total cholesterol, triglyceride, low density lipoprotein cholesterol (LDL-C), oxidized LDL-C, high density lipoprotein cholesterol (HDL-C), non-esterified fatty acid (NEFA), superoxide dismutase (SOD), catalase (CAT), methane dicarboxylic aldehyde (MDA), the expressions of SOD isoforms and glutathione peroxidase 1, as well as histopathological examination. In addition, generation of reactive oxygen species (ROS) was detected by 2'7'-dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescence. The results showed that UDCA alleviated renal ER stress-evoked cell death, oxidative stress, renal dysfunction, ROS production, upregulated the expression of Bcl-2 and suppressed Bax in vivo and in vitro. Hence, inhibition ER stress diminishes oxidative stress and exerts renoprotective effects.

The fibroblast expression of RANKL in CoCrMo-particle-induced osteolysis is mediated by ER stress and XBP1s.

PubMed

Wang, Zhenheng; Huang, Zhen; Gan, Jingjing; Liu, Naicheng; Zhou, Gang; Shi, Tongguo; Wang, Zhenzhen; Wang, Rui; Bao, Nirong; Guo, Ting; Chen, Jiangning; Zhang, Junfeng; Dong, Lei; Zhao, Jianning

2015-09-01

Particle-induced osteolysis is a major cause of aseptic loosening, which is the most common reason for total hip arthroplasty (THA) failure and revision surgery. Although existing studies suggest that synovial fibroblasts present in the interfacial membrane are important targets of wear particles during bone resorption, the interaction mechanisms between the particles and fibroblasts remains elusive. In the present study, we investigated the effect of ER stress induced by CoCrMo particles (CoPs) in fibroblasts, calvarial resorption animal models and aseptic loosening clinical samples and its role in the stimulation of the RANKL expression. Our study further demonstrated that CoPs could induce significant ER stress in fibroblasts. Blocking ER stress with a specific inhibitor dramatically reduced the particle-induced expression of RANKL in vitro and in vivo. Furthermore, in fibroblasts, downregulation of the expression of XBP1s, a signaling molecule of ER stress, significantly reduced the expression of RANKL induced by wear particles. Moreover, inhibition of ER stress or XBP1s both ameliorated the CoPs-induced osteolysis in animal models. Collectively, these results suggested that in particle-induced osteolysis, CoPs could stimulate fibroblasts to secret RANKL through ER stress and the signaling molecule XBP1s. Therefore, downregulating ER stress or the signaling molecule XBP1s of fibroblasts represents a potential therapeutic approach for treating particle-induced peri-implant osteolysis. For the first time, our study demonstrated that ER stress mediated the induction of RANKL expression by CoPs in fibroblasts and promoted particle-induced osteolysis. Furthermore, the upregulation of RANKL by CoPs in fibroblasts was mediated by the ER stress signaling molecule XBP1s. Both blocking ER stress and inhibiting the protein XBP1s by specific inhibitors resulted in downregulation of the expression of RANKL and amelioration of osteolysis induced by the implanted particles

Emodin induces apoptosis of lung cancer cells through ER stress and the TRIB3/NF-κB pathway.

PubMed

Su, Jin; Yan, Yan; Qu, Jingkun; Xue, Xuewen; Liu, Zi; Cai, Hui

2017-03-01

Emodin is a phytochemical with potent anticancer activities against various human malignant cancer types, including lung cancer; however, the molecular mechanisms underlying the effects of emodin remain unclear. In the present study, the A549 and H1299 human non-small lung cancer cell lines were treated with emodin and the induced molecular effects were investigated. Changes in cell viability were evaluated by MTT assay, Hoechst staining was used to indicate the apoptotic cells, and western blotting was utilized to assess endoplasmic reticulum (ER) stress and signaling changes. RNA interference was also employed to further examine the role of tribbles homolog 3 (TRIB3) in the emodin-induced apoptosis of lung cancer cells. Emodin was found to reduce the viability of lung cancer cells and induce apoptosis in a concentration-dependent manner. Emodin-induced apoptosis was impaired by inhibition of ER stress using 4-phenylbutyrate (4-PBA). ER stress and TRIB3/nuclear factor-κB signaling was activated in emodin-treated lung cancer cells. Emodin-induced apoptosis was reduced by TRIB3 knockdown in A549 cells, whereas ER stress was not reduced. In vivo assays verified the significance of these results, revealing that emodin inhibited lung cancer growth and that the inhibitory effects were reduced by inhibition of ER stress with 4-PBA. In conclusion, the results suggest that TRIB3 signaling is associated with emodin-induced ER stress-mediated apoptosis in lung cancer cells.

Understanding the origin of non-immune cell-mediated weakness in the idiopathic inflammatory myopathies - potential role of ER stress pathways.

PubMed

Lightfoot, Adam P; Nagaraju, Kanneboyina; McArdle, Anne; Cooper, Robert G

2015-11-01

Discussion of endoplasmic reticulum (ER) stress pathway activation in idiopathic inflammatory myopathies (IIM), and downstream mechanisms causative of muscle weakness. In IIM, ER stress is an important pathogenic process, but how it causes muscle dysfunction is unknown. We discuss relevant pathways modified in response to ER stress in IIM: reactive oxygen species (ROS) generation and mitochondrial dysfunction, and muscle cytokine (myokine) generation. First, ER stress pathway activation can induce changes in mitochondrial bioenergetics and ROS production. ROS can oxidize cellular components, causing muscle contractile dysfunction and energy deficits. Novel compounds targeting ROS generation and/or mitochondrial dysfunction can improve muscle function in several myopathologies. Second, recent research has demonstrated that skeletal muscle produces multiple myokines. It is suggested that these play a role in causing muscle weakness. Myokines are capable of immune cell recruitment, thus contributing to perturbed muscle function. A characterization of myokines in IIM would clarify their pathogenic role, and so identify new therapeutic targets. ER stress pathway activation is clearly of etiological relevance in IIM. Research to better understand mechanisms of weakness downstream of ER stress is now required, and which may discover new therapeutic targets for nonimmune cell-mediated weakness.

ER stress and subsequent activated calpain play a pivotal role in skeletal muscle wasting after severe burn injury

PubMed Central

Shen, Chuanan; Li, Dawei; Wang, Xiaoteng

2017-01-01

Severe burns are typically followed by hypermetabolism characterized by significant muscle wasting, which causes considerable morbidity and mortality. The aim of the present study was to explore the underlying mechanisms of skeletal muscle damage/wasting post-burn. Rats were randomized to the sham, sham+4-phenylbutyrate (4-PBA, a pharmacological chaperone promoting endoplasmic reticulum (ER) folding/trafficking, commonly considered as an inhibitor of ER), burn (30% total body surface area), and burn+4-PBA groups; and sacrificed at 1, 4, 7, 14 days after the burn injury. Tibial anterior muscle was harvested for transmission electron microscopy, calcium imaging, gene expression and protein analysis of ER stress / ubiquitin-proteasome system / autophagy, and calpain activity measurement. The results showed that ER stress markers were increased in the burn group compared with the sham group, especially at post-burn days 4 and 7, which might consequently elevate cytoplasmic calcium concentration, promote calpain production as well as activation, and cause skeletal muscle damage/wasting of TA muscle after severe burn injury. Interestingly, treatment with 4-PBA prevented burn-induced ER swelling and altered protein expression of ER stress markers and calcium release, attenuating calpain activation and skeletal muscle damage/wasting after severe burn injury. Atrogin-1 and LC3-II/LC3-I ratio were also increased in the burn group compared with the sham group, while MuRF-1 remained unchanged; 4-PBA decreased atrogin-1 in the burn group. Taken together, these findings suggested that severe burn injury induces ER stress, which in turns causes calpain activation. ER stress and subsequent activated calpain play a critical role in skeletal muscle damage/wasting in burned rats. PMID:29028830

Wogonin prevents rat dorsal root ganglion neurons death via inhibiting tunicamycin-induced ER stress in vitro.

PubMed

Xu, Shujuan; Zhao, Xin; Zhao, Quanlai; Zheng, Quan; Fang, Zhen; Yang, Xiaoming; Wang, Hong; Liu, Ping; Xu, Hongguang

2015-04-01

Wogonin is a natural flavonoid isolated from the root of Scutellaria baicalensis Georgi, which has been widely used in various research areas for its anti-oxidant, anti-inflammatory, and anti-cancer activities. It also presents a neuroprotective effect in the brain while encounters stress conditions, but the mechanisms controlling the neuroprotective effect of wogonin are not clear. In this study, we investigated the biomechanism underlying the neuroprotective effect of wogonin on rat dorsal root ganglion (DRG) neurons. Wogonin pre-treatment at 75 μM significantly increased the cell viability of DRG neurons and decreased the number of the propidium iodide-positive DRG neurons before the endoplasmic reticulum (ER) stress is being induced by tunicamycin (TUN) (0.75 μg/mL). In addition, Wogonin also inhibited the release of LDH and up-regulated the level of GSH. Furthermore, wogonin decreased the activation of ER stress-related molecules, including glucose-regulated protein 78 (GRP78), GRP94, C/EBP-homologous protein, active caspase12 and active caspase3, phosphorylation of pancreatic ER stress kinase, and eukaryotic initiation factor 2 alpha (eIF2α). In summary, our results indicated that wogonin could protect DRG neurons against TUN-induced ER stress.

O-GlcNAcylation of eIF2α regulates the phospho-eIF2α-mediated ER stress response.

PubMed

Jang, Insook; Kim, Han Byeol; Seo, Hojoong; Kim, Jin Young; Choi, Hyeonjin; Yoo, Jong Shin; Kim, Jae-woo; Cho, Jin Won

2015-08-01

O-GlcNAcylation is highly involved in cellular stress responses including the endoplasmic reticulum (ER) stress response. For example, glucosamine-induced flux through the hexosamine biosynthetic pathway can promote ER stress and ER stress inducers can change the total cellular level of O-GlcNAcylation. However, it is largely unknown which component(s) of the unfolded protein response (UPR) is directly regulated by O-GlcNAcylation. In this study, eukaryotic translation initiation factor 2α (eIF2α), a major branch of the UPR, was O-GlcNAcylated at Ser 219, Thr 239, and Thr 241. Upon ER stress, eIF2α is phosphorylated at Ser 51 by phosphorylated PKR-like ER kinase and this inhibits global translation initiation, except for that of specific mRNAs, including activating transcription factor 4, that induce stress-responsive genes such as C/EBP homologous protein (CHOP). Hyper-O-GlcNAcylation induced by O-GlcNAcase inhibitor (thiamet-G) treatment or O-GlcNAc transferase (OGT) overexpression hindered phosphorylation of eIF2α at Ser 51. The level of O-GlcNAcylation of eIF2α was changed by dithiothreitol treatment dependent on its phosphorylation at Ser 51. Point mutation of the O-GlcNAcylation sites of eIF2α increased its phosphorylation at Ser 51 and CHOP expression and resulted in increased apoptosis upon ER stress. These results suggest that O-GlcNAcylation of eIF2α affects its phosphorylation at Ser 51 and influences CHOP-mediated cell death. This O-GlcNAcylation of eIF2α was reproduced in thiamet-G-injected mouse liver. In conclusion, proper regulation of O-GlcNAcylation and phosphorylation of eIF2α is important to maintain cellular homeostasis upon ER stress. Copyright © 2015 Elsevier B.V. All rights reserved.

Activation of ER stress and mTORC1 suppresses hepatic sortilin-1 levels in obese mice

PubMed Central

Ai, Ding; Baez, Juan M.; Jiang, Hongfeng; Conlon, Donna M.; Hernandez-Ono, Antonio; Frank-Kamenetsky, Maria; Milstein, Stuart; Fitzgerald, Kevin; Murphy, Andrew J.; Woo, Connie W.; Strong, Alanna; Ginsberg, Henry N.; Tabas, Ira; Rader, Daniel J.; Tall, Alan R.

2012-01-01

Recent GWAS have identified SNPs at a human chromosom1 locus associated with coronary artery disease risk and LDL cholesterol levels. The SNPs are also associated with altered expression of hepatic sortilin-1 (SORT1), which encodes a protein thought to be involved in apoB trafficking and degradation. Here, we investigated the regulation of Sort1 expression in mouse models of obesity. Sort1 expression was markedly repressed in both genetic (ob/ob) and high-fat diet models of obesity; restoration of hepatic sortilin-1 levels resulted in reduced triglyceride and apoB secretion. Mouse models of obesity also exhibit increased hepatic activity of mammalian target of rapamycin complex 1 (mTORC1) and ER stress, and we found that administration of the mTOR inhibitor rapamycin to ob/ob mice reduced ER stress and increased hepatic sortilin-1 levels. Conversely, genetically increased hepatic mTORC1 activity was associated with repressed Sort1 and increased apoB secretion. Treating WT mice with the ER stressor tunicamycin led to marked repression of hepatic sortilin-1 expression, while administration of the chemical chaperone PBA to ob/ob mice led to amelioration of ER stress, increased sortilin-1 expression, and reduced apoB and triglyceride secretion. Moreover, the ER stress target Atf3 acted at the SORT1 promoter region as a transcriptional repressor, whereas knockdown of Atf3 mRNA in ob/ob mice led to increased hepatic sortilin-1 levels and decreased apoB and triglyceride secretion. Thus, in mouse models of obesity, induction of mTORC1 and ER stress led to repression of hepatic Sort1 and increased VLDL secretion via Atf3. This pathway may contribute to dyslipidemia in metabolic disease. PMID:22466652

Interaction between endoplasmic/sarcoplasmic reticulum stress (ER/SR stress), mitochondrial signaling and Ca2+ regulation in airway smooth muscle (ASM)1

PubMed Central

Delmotte, Philippe; Sieck, Gary C.

2015-01-01

Airway inflammation is a key aspect of diseases such as asthma. Several inflammatory cytokines (e.g., TNFα and IL-13) increase cytosolic Ca2+ ([Ca2+]cyt) responses to agonist stimulation and Ca2+ sensitivity of force generation, thereby enhancing airway smooth muscle (ASM) contractility (hyper-reactive state). Inflammation also induces ASM proliferation and remodeling (synthetic state). In normal ASM, the transient elevation of [Ca2+]cyt induced by agonists leads to a transient increase in mitochondrial Ca2+ ([Ca2+]mito) that may be important in matching ATP production with ATP consumption. In human ASM (hASM) exposed to TNFα and IL-13, the transient increase in [Ca2+]mito is blunted despite enhanced [Ca2+]cyt responses. We also found that TNFα and IL-13 induce reactive oxidant species (ROS) formation and endoplasmic/sarcoplasmic reticulum (ER/SR) stress (unfolded protein response) in hASM. ER/SR stress in hASM is associated with disruption of mitochondrial coupling with the ER/SR membrane, which relates to reduced mitofusin 2 (Mfn2) expression. Thus, in hASM it appears that TNFα and IL-13 result in ROS formation leading to ER/SR stress, reduced Mfn2 expression, disruption of mitochondrion–ER/SR coupling, decreased mitochondrial Ca2+ buffering, mitochondrial fragmentation, and increased cell proliferation. PMID:25506723

ER Stress Induced by Tunicamycin Triggers α-Synuclein Oligomerization, Dopaminergic Neurons Death and Locomotor Impairment: a New Model of Parkinson's Disease.

PubMed

Cóppola-Segovia, Valentín; Cavarsan, Clarissa; Maia, Flavia G; Ferraz, Anete C; Nakao, Lia S; Lima, Marcelo Ms; Zanata, Silvio M

2017-10-01

Parkinson's disease (PD) is a neurodegenerative disorder characterized by progressive death of dopaminergic neurons of the substantia nigra pars compacta (SNpc), leading to the major clinical abnormalities that characterize this disease. Although PD's etiology is unknown, α-synuclein aggregation plays a pivotal role in PD pathogenesis, which could be associated to some pathological processes such as oxidative stress, endoplasmic reticulum (ER) stress, impaired protein degradation, and mitochondrial dysfunction. Increasing experimental evidence indicates that ER stress is involved in PD, however most of the described results employed cultured cell lines and genetically modified animal models. In this study, we developed a new ER stress rat model employing the well-known ER stressor tunicamycin (Tm). To evaluate if ER stress was able to induce PD features, we performed an intranigral injection of Tm (0.1 μg/cerebral hemisphere) and animals (male Wistar rats) were analyzed 7 days post injection. The classical 6-OHDA neurotoxin model (1 μg/cerebral hemisphere) was used as an established positive control for PD. We show that Tm injection induced locomotor impairment, dopaminergic neurons death, and activation of astroglia. In addition, we observed an extensive α-synuclein oligomerization in SNpc of Tm-injected animals when compared with DMSO-injected controls. Finally, both Tm and 6-OHDA treated animals presented increased levels of ER stress markers. Taken together, these findings show for the first time that the ER stressor Tm recapitulates some of the phenotypic characteristics observed in rodent models of PD, reinforcing the concept that ER stress could be an important contributor to the pathophysiology of PD. Therefore, we propose the intranigral Tm injection as a new ER stress-based model for the study of PD in vivo.

Tranilast-induced stress alleviation in solid tumors improves the efficacy of chemo- and nanotherapeutics in a size-independent manner

NASA Astrophysics Data System (ADS)

Papageorgis, Panagiotis; Polydorou, Christiana; Mpekris, Fotios; Voutouri, Chrysovalantis; Agathokleous, Eliana; Kapnissi-Christodoulou, Constantina P.; Stylianopoulos, Triantafyllos

2017-04-01

Accumulation of mechanical stresses during cancer progression can induce blood and lymphatic vessel compression, creating hypo-perfusion, hypoxia and interstitial hypertension which decrease the efficacy of chemo- and nanotherapies. Stress alleviation treatment has been recently proposed to reduce mechanical stresses in order to decompress tumor vessels and improve perfusion and chemotherapy. However, it remains unclear if it improves the efficacy of nanomedicines, which present numerous advantages over traditional chemotherapeutic drugs. Furthermore, we need to identify safe and well-tolerated pharmaceutical agents that reduce stress levels and may be added to cancer patients’ treatment regimen. Here, we show mathematically and with a series of in vivo experiments that stress alleviation improves the delivery of drugs in a size-independent manner. Importantly, we propose the repurposing of tranilast, a clinically approved anti-fibrotic drug as stress-alleviating agent. Using two orthotopic mammary tumor models, we demonstrate that tranilast reduces mechanical stresses, decreases interstitial fluid pressure (IFP), improves tumor perfusion and significantly enhances the efficacy of different-sized drugs, doxorubicin, Abraxane and Doxil, by suppressing TGFβ signaling and expression of extracellular matrix components. Our findings strongly suggest that repurposing tranilast could be directly used as a promising strategy to enhance, not only chemotherapy, but also the efficacy of cancer nanomedicine.

Eucommia ulmoides Oliver Extract, Aucubin, and Geniposide Enhance Lysosomal Activity to Regulate ER Stress and Hepatic Lipid Accumulation

PubMed Central

Lee, Hwa-Young; Lee, Geum-Hwa; Lee, Mi-Rin; Kim, Hye-Kyung; Kim, Nan-young; Kim, Seung-Hyun; Lee, Yong-Chul; Kim, Hyung-Ryong; Chae, Han-Jung

2013-01-01

Eucommia ulmoides Oliver is a natural product widely used as a dietary supplement and medicinal plant. Here, we examined the potential regulatory effects of Eucommia ulmoides Oliver extracts (EUE) on hepatic dyslipidemia and its related mechanisms by in vitro and in vivo studies. EUE and its two active constituents, aucubin and geniposide, inhibited palmitate-induced endoplasmic reticulum (ER) stress, reducing hepatic lipid accumulation through secretion of apolipoprotein B and associated triglycerides and cholesterol in human HepG2 hepatocytes. To determine how EUE diminishes the ER stress response, lysosomal and proteasomal protein degradation activities were analyzed. Although proteasomal activity was not affected, lysosomal enzyme activities including V-ATPase were significantly increased by EUE as well as aucubin and geniposide in HepG2 cells. Treatment with the V-ATPase inhibitor, bafilomycin, reversed the inhibition of ER stress, secretion of apolipoprotein B, and hepatic lipid accumulation induced by EUE or its component, aucubin or geniposide. In addition, EUE was determined to regulate hepatic dyslipidemia by enhancing lysosomal activity and to regulate ER stress in rats fed a high-fat diet. Together, these results suggest that EUE and its active components enhance lysosomal activity, resulting in decreased ER stress and hepatic dyslipidemia. PMID:24349058

Intrarenal renin-angiotensin system mediates fatty acid-induced ER stress in the kidney

PubMed Central

Li, Chunling; Lin, Yu; Luo, Renfei; Chen, Shaoming; Zheng, Peili; Levi, Moshe; Yang, Tianxin; Wang, Weidong

2015-01-01

Obesity-related kidney disease is related to caloric excess promoting deleterious cellular responses. Accumulation of saturated free fatty acids in tubular cells produces lipotoxicity involving significant cellular dysfunction and injury. The objectives of this study were to elucidate the role of renin-angiotensin system (RAS) activation in saturated fatty acid-induced endoplasmic reticulum (ER) stress in cultured human proximal tubule epithelial cells (HK2) and in mice fed with a high-fat diet. Treatment with saturated fatty acid palmitic acid (PA; 0.8 mM) for 24 h induced ER stress in HK2, leading to an unfolded protein response as reflected by increased expressions of the ER chaperone binding immunoglobulin protein (BiP) and proapoptotic transcription factor C/EBP homologous protein (CHOP) protein as evaluated by immunoblotting. PA treatment also induced increased protein expression of inositol requiring protein 1α (IRE1α), phosphorylated eukaryotic initiation factor-α (eIF2α), and activating transcription factor 4 (ATF4) as well as activation of caspase-3. PA treatment was associated with increased angiotensin II levels in cultured medium. The angiotensin II type 1 receptor (AT1R) blocker valsartan or renin inhibitor aliskiren dramatically suppressed PA-induced upregulation of BiP, CHOP, IRE1α, p-eIF2α, and ATF4 in HK2 cells. In contrast, valsartan or aliskiren did not prevent ER stress induced by tunicamycin. C57BL/6 mice fed with a high-fat diet for 14 wk exhibited increased protein expressions of BiP and CHOP compared with control mice, which were significantly attenuated by the valsartan treatment. Increased angiotensin II levels in serum and urine were observed in mice fed with a high-fat diet when compared with controls. It is suggested that the intrarenal RAS activation may play an important role in diabetic kidney injury via mediating ER stress induced by saturated fatty acid. PMID:26672616

Arbuscular mycorrhizal fungi alleviate boron toxicity in Puccinellia tenuiflora under the combined stresses of salt and drought.

PubMed

Liu, Chunguang; Dai, Zheng; Cui, Mengying; Lu, Wenkai; Sun, Hongwen

2018-05-11

To investigate the effect of arbuscular mycorrhizal fungi (AMF) on boron (B) toxicity in plants under the combined stresses of salt and drought, Puccinellia tenuiflora was grown in the soil with the inoculation of Funneliformis mosseae and Claroideoglomus etunicatum. After three weeks of treatment, the plants were harvested to determine mycorrhizal colonization rates, plant biomass, as well as tissue B, phosphorus, sodium, and potassium concentrations. The results show that the combined stresses reduced mycorrhizal colonization. Mycorrhizal inoculation significantly increased plant biomass while reduced shoot B concentrations. Mycorrhizal inoculation also slightly increased shoot phosphorus and potassium concentrations, and reduced shoot sodium concentrations. F. mosseae and C. etunicatum were able to alleviate the combined stresses of B, salt, and drought. The two fungal species and their combination showed no significant difference in the alleviation of B toxicity. It is inferred that AMF is able to alleviate B toxicity in P. tenuiflora by increasing biomass and reducing tissue B concentrations. The increase in plant phosphorus and potassium, as well as the decrease in sodium accumulation that induced by AMF, can help plant tolerate the combined stresses of salt and drought. Our findings suggest that F. mosseae and C. etunicatum are potential candidates for facilitating the phytoremediation of B-contaminated soils with salt and drought stress. Copyright © 2018 Elsevier Ltd. All rights reserved.

Adaptation to ER Stress Is Mediated by Differential Stabilities of Pro-Survival and Pro-Apoptotic mRNAs and Proteins

PubMed Central

Rutkowski, D. Thomas; Arnold, Stacey M; Miller, Corey N; Wu, Jun; Li, Jack; Gunnison, Kathryn M; Mori, Kazutoshi; Sadighi Akha, Amir A.; Raden, David; Kaufman, Randal J

2006-01-01

The accumulation of unfolded proteins in the endoplasmic reticulum (ER) activates a signaling cascade known as the unfolded protein response (UPR). Although activation of the UPR is well described, there is little sense of how the response, which initiates both apoptotic and adaptive pathways, can selectively allow for adaptation. Here we describe the reconstitution of an adaptive ER stress response in a cell culture system. Monitoring the activation and maintenance of representative UPR gene expression pathways that facilitate either adaptation or apoptosis, we demonstrate that mild ER stress activates all UPR sensors. However, survival is favored during mild stress as a consequence of the intrinsic instabilities of mRNAs and proteins that promote apoptosis compared to those that facilitate protein folding and adaptation. As a consequence, the expression of apoptotic proteins is short-lived as cells adapt to stress. We provide evidence that the selective persistence of ER chaperone expression is also applicable to at least one instance of genetic ER stress. This work provides new insight into how a stress response pathway can be structured to allow cells to avert death as they adapt. It underscores the contribution of posttranscriptional and posttranslational mechanisms in influencing this outcome. PMID:17090218

Impaired autophagy activity is linked to elevated ER-stress and inflammation in aging adipose tissue.

PubMed

Ghosh, Amiya Kumar; Mau, Theresa; O'Brien, Martin; Garg, Sanjay; Yung, Raymond

2016-10-24

Adipose tissue dysfunction in aging is associated with inflammation, metabolic syndrome and other diseases. We propose that impaired protein homeostasis due to compromised lysosomal degradation (micro-autophagy) might promote aberrant ER stress response and inflammation in aging adipose tissue. Using C57BL/6 mouse model, we demonstrate that adipose tissue-derived stromal vascular fraction (SVF) cells from old (18-20 months) mice have reduced expression of autophagy markers as compared to the younger (4-6 months) cohort. Elevated expressions of ER-stress marker CHOP and autophagy substrate SQSTM1/p62 are observed in old SVFs compared to young, when treated with either vehicle or with thapsigargin (Tg), an ER stress inducer. Treatment with bafilomycin A1 (Baf), a vacuolar-type H (+)-ATPase, or Tg elevated expressions of CHOP, and SQSTM1/p62 and LC-3-II, in 3T3-L1-preadipocytes. We also demonstrate impaired autophagy activity in old SVFs by analyzing increased accumulation of autophagy substrates LC3-II and p62. Compromised autophagy activity in old SVFs is correlated with enhanced release of pro-inflammatory cytokines IL-6 and MCP-1. Finally, SVFs from calorie restricted old mice (CR-O) have shown enhanced autophagy activity compared to ad libitum fed old mice (AL-O). Our results support the notion that diminished autophagy activity with aging contributes to increased adipose tissue ER stress and inflammation.

Sigma receptor 1 modulates ER stress and Bcl2 in murine retina.

PubMed

Ha, Yonju; Shanmugam, Arul K; Markand, Shanu; Zorrilla, Eric; Ganapathy, Vadivel; Smith, Sylvia B

2014-04-01

Sigma receptor 1 (σR1), a non-opiate transmembrane protein located on endoplasmic reticulum (ER) and mitochondrial membranes, is considered to be a molecular chaperone. Marked protection against cell death has been observed when ligands for σR1 have been used in in vitro and in vivo models of retinal cell death. Mice lacking σR1 (σR1(-/-)) manifest late-onset loss of retinal ganglion cells and retinal electrophysiological changes (after many months). The role of σR1 in the retina and the mechanisms by which its ligands afford neuroprotection are unclear. We therefore used σR1(-/-) mice to investigate the expression of ER stress genes (BiP/GRP78, Atf6, Atf4, Ire1α) and proteins involved in apoptosis (BCL2, BAX) and to examine the retinal transcriptome at young ages. Whereas no significant changes occurred in the expression of major ER stress genes (over a period of a year) in neural retina, marked changes were observed in these genes, especially Atf6, in isolated retinal Müller glial cells. BCL2 levels decreased in σR1(-/-) retina concomitantly with decreases in NFkB and pERK1/2. We postulate that σR1 regulates ER stress in retinal Müller cells and that the role of σR1 in retinal neuroprotection probably involves BCL2 and some of the proteins that modify its expression (such as ERK, NFκB). Data from the analysis of the retinal transcriptome of σR1 null mice provide new insights into the role of σR1 in retinal neuroprotection.

Sigma receptor 1 modulates ER stress and Bcl2 in murine retina

PubMed Central

Ha, Yonju; Shanmugam, Arul K.; Markand, Shanu; Zorrilla, Eric; Ganapathy, Vadivel; Smith, Sylvia B.

2014-01-01

Sigma receptor 1 (σR1), a non-opiate transmembrane protein located on endoplasmic reticulum (ER) and mitochondrial membranes, is considered a molecular chaperone. Marked protection against cell death has been observed when ligands for σR1 have been used in in vitro and in vivo models of retinal cell death. Mice lacking σR1 (σR1−/−) manifest late onset loss of retinal ganglion cells and retinal electrophysiological changes (after many months). The role of σR1 in retina and the mechanisms by which its ligands afford neuroprotection are unclear. To explore this we used σR1−/− mice and investigated expression of ER stress genes (BiP/GRP78, Atf6, Atf4, Ire1α) and proteins involved in apoptosis (BCL2, BAX) and examined the retinal transcriptome at young ages. While there were no significant changes in expression of major ER stress genes (over a period of a year) in neural retina, there were marked changes in these genes especially Atf6 in isolated retinal Müller glial cells. BCL2 levels decreased in σR1−/− retina concomitant with decreases in NFkB and pERK1/2. We postulate that σR1 regulates ER stress in retinal Müller cells and that the role of σR1 in retinal neuroprotection likely involves BCL2 and some of the proteins that modify its expression (such as ERK, NFκB). Data from the analysis of the retinal transcriptome of σR1 null mice provides new avenues to understand the role of σR1 in retinal neuroprotection. PMID:24469320

Pachymic acid inhibits growth and induces apoptosis of pancreatic cancer in vitro and in vivo by targeting ER stress.

PubMed

Cheng, Shujie; Swanson, Kristen; Eliaz, Isaac; McClintick, Jeanette N; Sandusky, George E; Sliva, Daniel

2015-01-01

Pachymic acid (PA) is a purified triterpene extracted from medicinal fungus Poria cocos. In this paper, we investigated the anticancer effect of PA on human chemotherapy resistant pancreatic cancer. PA triggered apoptosis in gemcitabine-resistant pancreatic cancer cells PANC-1 and MIA PaCa-2. Comparative gene expression array analysis demonstrated that endoplasmic reticulum (ER) stress was induced by PA through activation of heat shock response and unfolded protein response related genes. Induced ER stress was confirmed by increasing expression of XBP-1s, ATF4, Hsp70, CHOP and phospho-eIF2α. Moreover, ER stress inhibitor tauroursodeoxycholic acid (TUDCA) blocked PA induced apoptosis. In addition, 25 mg kg-1 of PA significantly suppressed MIA PaCa-2 tumor growth in vivo without toxicity, which correlated with induction of apoptosis and expression of ER stress related proteins in tumor tissues. Taken together, growth inhibition and induction of apoptosis by PA in gemcitabine-resistant pancreatic cancer cells were associated with ER stress activation both in vitro and in vivo. PA may be potentially exploited for the use in treatment of chemotherapy resistant pancreatic cancer.

Establishment of pancreatic microenvironment model of ER stress: Quercetin attenuates β-cell apoptosis by invoking nitric oxide-cGMP signaling in endothelial cells.

PubMed

Suganya, Natarajan; Mani, Krishna Priya; Sireesh, Dornadula; Rajaguru, Palanisamy; Vairamani, Mariappanadar; Suresh, Thiruppathi; Suzuki, Takayoshi; Chatterjee, Suvro; Ramkumar, Kunka Mohanram

2018-05-01

The involvement of endoplasmic reticulum (ER) stress in endothelial dysfunction and diabetes-associated complications has been well documented. Inhibition of ER stress represents a promising therapeutic strategy to attenuate endothelial dysfunction in diabetes. Recent attention has focused on the development of small molecule inhibitors of ER stress to maintain endothelial homeostasis in diabetes. Here we have developed a reliable, robust co-culture system that allows a study on the endothelial cells and pancreatic β-cells crosstalk under ER stress and validated using a known ER stress modulator, quercetin. Furthermore, sensitizing of endothelial cells by quercetin (25 μM) confers protection of pancreatic β-cells against ER stress through nitric oxide (NO ∙ ) signaling. In addition, increased intracellular insulin and NO ∙ -mediated cyclic 3',5'-guanosine monophosphate (cGMP) levels in pancreatic β-cells further confirmed the mechanism of protection under co-culture system. In addition, the potential protein targets of quercetin against ER stress in the endothelial cells were investigated through proteomic profiling and its phosphoprotein targets through Bioplex analysis. On the whole, the developed in vitro co-culture set up can serve as a platform to study the signaling network between the endothelial and pancreatic β-cells as well as provides a mechanistic insight for the validation of novel ER stress modulators. Copyright © 2018 Elsevier Inc. All rights reserved.

Sodium Phenylbutyrate and Edaravone Abrogate Chronic Restraint Stress-Induced Behavioral Deficits: Implication of Oxido-Nitrosative, Endoplasmic Reticulum Stress Cascade, and Neuroinflammation.

PubMed

Jangra, Ashok; Sriram, Chandra Shaker; Dwivedi, Shubham; Gurjar, Satendra Singh; Hussain, Md Iftikar; Borah, Probodh; Lahkar, Mangala

2017-01-01

Chronic stress exposure can produce deleterious effects on the hippocampus (HC) which eventually leads to cognitive impairment and depression. Endoplasmic reticulum (ER) stress has been reported as one of the major culprits in the development of stress-induced cognitive impairment and depression. We investigated the neuroprotective efficacy of sodium phenylbutyrate (SPB), an ER stress inhibitor, and edaravone, a free radical scavenger, against chronic restraint stress (CRS)-induced cognitive deficits and anxiety- and depressive-like behavior in mice. Adult male Swiss albino mice were restrained for 6 h/day for 28 days and injected (i.p.) with SPB (40 and 120 mg/kg) or edaravone (3 and 10 mg/kg) for the last seven days. After stress cessation, the anxiety- and depressive-like behavior along with spatial learning and memory were examined. Furthermore, oxido-nitrosative stress, proinflammatory cytokines, and gene expression level of ER stress-related genes were assessed in HC and prefrontal cortex (PFC). CRS-exposed mice showed anxiety- and depressive-like behavior, which was significantly improved by SPB and edaravone treatment. In addition, SPB and edaravone treatment significantly alleviated CRS-induced spatial learning and memory impairment. Furthermore, CRS-evoked oxido-nitrosative stress, neuroinflammation, and depletion of Brain-derived neurotrophic factor were significantly ameliorated by SPB and edaravone treatment. We found significant up-regulation of ER stress-related genes in both HC and PFC regions, which were suppressed by SPB and edaravone treatment in CRS mice. Our study provides evidence that SPB and edaravone exerted neuroprotective effects on CRS-induced cognitive deficits and anxiety- and depressive-like behavior, which is possibly coupled with inhibition of oxido-nitrosative stress, neuroinflammation, and ER stress cascade.

Calorie-induced ER stress suppresses uroguanylin satiety signaling in diet-induced obesity

PubMed Central

Kim, G W; Lin, J E; Snook, A E; Aing, A S; Merlino, D J; Li, P; Waldman, S A

2016-01-01

Background/Objectives: The uroguanylin-GUCY2C gut–brain axis has emerged as one component regulating feeding, energy homeostasis, body mass and metabolism. Here, we explore a role for this axis in mechanisms underlying diet-induced obesity (DIO). Subjects/Methods: Intestinal uroguanylin expression and secretion, and hypothalamic GUCY2C expression and anorexigenic signaling, were quantified in mice on high-calorie diets for 14 weeks. The role of endoplasmic reticulum (ER) stress in suppressing uroguanylin in DIO was explored using tunicamycin, an inducer of ER stress, and tauroursodeoxycholic acid (TUDCA), a chemical chaperone that inhibits ER stress. The impact of consumed calories on uroguanylin expression was explored by dietary manipulation. The role of uroguanylin in mechanisms underlying obesity was examined using Camk2a-Cre-ERT2-Rosa-STOPloxP/loxP-Guca2b mice in which tamoxifen induces transgenic hormone expression in brain. Results: DIO suppressed intestinal uroguanylin expression and eliminated its postprandial secretion into the circulation. DIO suppressed uroguanylin through ER stress, an effect mimicked by tunicamycin and blocked by TUDCA. Hormone suppression by DIO reflected consumed calories, rather than the pathophysiological milieu of obesity, as a diet high in calories from carbohydrates suppressed uroguanylin in lean mice, whereas calorie restriction restored uroguanylin in obese mice. However, hypothalamic GUCY2C, enriched in the arcuate nucleus, produced anorexigenic signals mediating satiety upon exogenous agonist administration, and DIO did not impair these responses. Uroguanylin replacement by transgenic expression in brain repaired the hormone insufficiency and reconstituted satiety responses opposing DIO and its associated comorbidities, including visceral adiposity, glucose intolerance and hepatic steatosis. Conclusions: These studies reveal a novel pathophysiological mechanism contributing to obesity in which calorie-induced suppression

Genome-wide screen identifies a novel p97/CDC-48-dependent pathway regulating ER-stress-induced gene transcription

PubMed Central

Marza, Esther; Taouji, Saïd; Barroso, Kim; Raymond, Anne-Aurélie; Guignard, Léo; Bonneu, Marc; Pallares-Lupon, Néstor; Dupuy, Jean-William; Fernandez-Zapico, Martin E; Rosenbaum, Jean; Palladino, Francesca; Dupuy, Denis; Chevet, Eric

2015-01-01

The accumulation of misfolded proteins in the endoplasmic reticulum (ER) activates the Unfolded Protein Response (UPRER) to restore ER homeostasis. The AAA+ ATPase p97/CDC-48 plays key roles in ER stress by promoting both ER protein degradation and transcription of UPRER genes. Although the mechanisms associated with protein degradation are now well established, the molecular events involved in the regulation of gene transcription by p97/CDC-48 remain unclear. Using a reporter-based genome-wide RNAi screen in combination with quantitative proteomic analysis in Caenorhabditis elegans, we have identified RUVB-2, a AAA+ ATPase, as a novel repressor of a subset of UPRER genes. We show that degradation of RUVB-2 by CDC-48 enhances expression of ER stress response genes through an XBP1-dependent mechanism. The functional interplay between CDC-48 and RUVB-2 in controlling transcription of select UPRER genes appears conserved in human cells. Together, these results describe a novel role for p97/CDC-48, whereby its role in protein degradation is integrated with its role in regulating expression of ER stress response genes. PMID:25652260

Thiamine deficiency induces endoplasmic reticulum stress and oxidative stress in human neurons derived from induced pluripotent stem cells.

PubMed

Wang, Xin; Xu, Mei; Frank, Jacqueline A; Ke, Zun-Ji; Luo, Jia

2017-04-01

Thiamine (vitamin B1) deficiency (TD) plays a major role in the etiology of Wernicke's encephalopathy (WE) which is a severe neurological disorder. TD induces selective neuronal cell death, neuroinflammation, endoplasmic reticulum (ER) stress and oxidative stress in the brain which are commonly observed in many aging-related neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD) and progressive supranuclear palsy (PSP). However, the underlying cellular and molecular mechanisms remain unclear. The progress in this line of research is hindered due to the lack of appropriate in vitro models. The neurons derived for the human induced pluripotent stem cells (hiPSCs) provide a relevant and powerful tool for the research in pharmaceutical and environmental neurotoxicity. In this study, we for the first time used human induced pluripotent stem cells (hiPSCs)-derived neurons (iCell neurons) to investigate the mechanisms of TD-induced neurodegeneration. We showed that TD caused a concentration- and duration-dependent death of iCell neurons. TD induced ER stress which was evident by the increase in ER stress markers, such as GRP78, XBP-1, CHOP, ATF-6, phosphorylated eIF2α, and cleaved caspase-12. TD also triggered oxidative stress which was shown by the increase in the expression 2,4-dinitrophenyl (DNP) and 4-hydroxynonenal (HNE). ER stress inhibitors (STF-083010 and salubrinal) and antioxidant N-acetyl cysteine (NAC) were effective in alleviating TD-induced death of iCell neurons, supporting the involvement of ER stress and oxidative stress. It establishes that the iCell neurons are a novel tool to investigate cellular and molecular mechanisms for TD-induced neurodegeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

Familial CJD Associated PrP Mutants within Transmembrane Region Induced Ctm-PrP Retention in ER and Triggered Apoptosis by ER Stress in SH-SY5Y Cells

PubMed Central

Wang, Xin; Shi, Qi; Xu, Kun; Gao, Chen; Chen, Cao; Li, Xiao-Li; Wang, Gui-Rong; Tian, Chan; Han, Jun; Dong, Xiao-Ping

2011-01-01

Background Genetic prion diseases are linked to point and inserted mutations in the prion protein (PrP) gene that are presumed to favor conversion of the cellular isoform of PrP (PrPC) to the pathogenic one (PrPSc). The pathogenic mechanisms and the subcellular sites of the conversion are not completely understood. Here we introduce several PRNP gene mutations (such as, PrP-KDEL, PrP-3AV, PrP-A117V, PrP-G114V, PrP-P102L and PrP-E200K) into the cultured cells in order to explore the pathogenic mechanism of familial prion disease. Methodology/Principal Findings To address the roles of aberrant retention of PrP in endoplasmic reticulum (ER), the recombinant plasmids expressing full-length human PrP tailed with an ER signal peptide at the COOH-terminal (PrP-KDEL) and PrP with three amino acids exchange in transmembrane region (PrP-3AV) were constructed. In the preparations of transient transfections, 18-kD COOH-terminal proteolytic resistant fragments (Ctm-PrP) were detected in the cells expressing PrP-KDEL and PrP-3AV. Analyses of the cell viabilities in the presences of tunicamycin and brefeldin A revealed that expressions of PrP-KDEL and PrP-3AV sensitized the transfected cells to ER stress stimuli. Western blots and RT-PCR identified the clear alternations of ER stress associated events in the cells expressing PrP-KDEL and PrP-3AV that induced ER mediated apoptosis by CHOP and capase-12 apoptosis pathway. Moreover, several familial CJD related PrP mutants were transiently introduced into the cultured cells. Only the mutants within the transmembrane region (G114V and A117V) induced the formation of Ctm-PrP and caused the ER stress, while the mutants outside the transmembrane region (P102L and E200K) failed. Conclusions/Significance The data indicate that the retention of PrP in ER through formation of Ctm-PrP results in ER stress and cell apoptosis. The cytopathic activities caused by different familial CJD associated PrP mutants may vary, among them the mutants

A short-term supranutritional vitamin E supplementation alleviated respiratory alkalosis but did not reduce oxidative stress in heat stressed pigs.

PubMed

Liu, Fan; Celi, Pietro; Chauhan, Surinder Singh; Cottrell, Jeremy James; Leury, Brian Joseph; Dunshea, Frank Rowland

2018-02-01

Heat stress (HS) triggers oxidative stress and respiratory alkalosis in pigs. The objective of this experiment was to study whether a short-term supranutritional amount of dietary vitamin E (VE) can mitigate oxidative stress and respiratory alkalosis in heat-stressed pigs. A total of 24 pigs were given either a control diet (17 IU/kg VE) or a high VE (200 IU/kg VE; HiVE) diet for 14 d, then exposed to thermoneutral (TN; 20°C, 45% humidity) or HS (35°C, 35% to 45% humidity, 8 h daily) conditions for 7 d. Respiration rate and rectal temperature were measured three times daily during the thermal exposure. Blood gas variables and oxidative stress markers were studied in blood samples collected on d 7. Although HiVE diet did not affect the elevated rectal temperature or respiration rate observed during HS, it alleviated (all p<0.05 for diet×temperature) the loss of blood CO 2 partial pressure and bicarbonate, as well as the increase in blood pH in the heat-stressed pigs. The HS reduced (p = 0.003) plasma biological antioxidant potential (BAP) and tended to increase (p = 0.067) advanced oxidized protein products (AOPP) in the heat-stressed pigs, suggesting HS triggers oxidative stress. The HiVE diet did not affect plasma BAP or AOPP. Only under TN conditions the HiVE diet reduced the plasma reactive oxygen metabolites (p<0.05 for diet× temperature). A short-term supplementation with 200 IU/kg VE partially alleviated respiratory alkalosis but did not reduce oxidative stress in heat-stressed pigs.

ERK1/2-dependent bestrophin-3 expression prevents ER-stress-induced cell death in renal epithelial cells by reducing CHOP.

PubMed

Lee, Wing-Kee; Chakraborty, Prabir K; Roussa, Eleni; Wolff, Natascha A; Thévenod, Frank

2012-10-01

Upon endoplasmic reticulum (ER) stress induction, cells endeavor to survive by engaging the adaptive stress response known as the unfolded protein response or by removing aggregated proteins via autophagy. Chronic ER stress culminates in apoptotic cell death, which involves induction of pro-apoptotic CHOP. Here, we show that bestrophin-3 (Best-3), a protein previously associated with Ca(2+)-activated Cl(-) channel activity, is upregulated by the ER stressors, thapsigargin (TG), tunicamycin (TUN) and the toxic metal Cd(2+). In cultured rat kidney proximal tubule cells, ER stress, CHOP and cell death were induced after 6h by Cd(2+) (25μM), TG (3μM) and TUN (6μM), were associated with increased cytosolic Ca(2+) and downstream formation of reactive oxygen species and attenuated by the Ca(2+) chelator BAPTA-AM (10μM), the antioxidant α-tocopherol (100μM), or overexpression of catalase (CAT). Immunofluorescence staining showed Best-3 expression in the plasma membrane, nuclei and intracellular compartments, though not in the ER, in cultured cells and rat kidney cortex sections. Best-3 mRNA was augmented by ER stress and signaled through increased Ca(2+), oxidative stress and ERK1/2 phosphorylation, because it was attenuated by α-tocopherol, CAT expression, BAPTA-AM, calmodulin kinase inhibitor calmidazolium (40μM), ERK1/2 inhibitor U0126 (10μM), and ERK1/2 RNAi. Knockdown of Best-3 resulted in decreased cell number consequentially of cell death, as determined by nuclear staining and PARP-1 cleavage. Furthermore, reduced ER stress-cell death by Best-3 overexpression is attributed to diminished CHOP. Since Best-3 overexpression did not affect upstream signaling pathways, we hypothesize that Best-3 possibly interferes with CHOP transcription. From our novel observations, we conclude that ERK1/2-dependent Best-3 activation regulates cell fate decisions during ER stress by suppressing CHOP induction and death. Copyright © 2012 Elsevier B.V. All rights reserved.

Parasite-induced ER stress response in hepatocytes facilitates Plasmodium liver stage infection.

PubMed

Inácio, Patricia; Zuzarte-Luís, Vanessa; Ruivo, Margarida T G; Falkard, Brie; Nagaraj, Nagarjuna; Rooijers, Koos; Mann, Matthias; Mair, Gunnar; Fidock, David A; Mota, Maria M

2015-08-01

Upon infection of a mammalian host, Plasmodium parasites first replicate inside hepatocytes, generating thousands of new parasites. Although Plasmodium intra-hepatic development represents a substantial metabolic challenge to the host hepatocyte, how infected cells respond to and integrate this stress remains poorly understood. Here, we present proteomic and transcriptomic analyses, revealing that the endoplasmic reticulum (ER)-resident unfolded protein response (UPR) is activated in host hepatocytes upon Plasmodium berghei infection. The expression of XBP1s--the active form of the UPR mediator XBP1--and the liver-specific UPR mediator CREBH is induced by P. berghei infection in vivo. Furthermore, this UPR induction increases parasite liver burden. Altogether, our data suggest that ER stress is a central feature of P. berghei intra-hepatic development, contributing to the success of infection. © 2015 The Authors.

DEFECTIVE TRAFFICKING OF CONE PHOTORECEPTOR CNG CHANNELS INDUCES THE UNFOLDED PROTEIN RESPONSE AND ER STRESS-ASSOCIATED CELL DEATH

PubMed Central

Duricka, Deborah L.; Brown, R. Lane; Varnum, Michael D.

2011-01-01

SYNOPSIS Mutations that perturb the function of photoreceptor cyclic nucleotide-gated (CNG) channels are associated with several human retinal disorders, but the molecular and cellular mechanisms leading to photoreceptor dysfunction and degeneration remain unclear. Many loss-of-function mutations result in intracellular accumulation of CNG channel subunits. Accumulation of proteins in the endoplasmic reticulum (ER) is known to cause ER stress and trigger the unfolded protein response (UPR), an evolutionarily conserved cellular program that results in either adaptation via increased protein processing capacity or apoptotic cell death. We hypothesize that defective trafficking of cone photoreceptor CNG channels can induce UPR-mediated cell death. To test this idea, CNGA3 subunits bearing the R563H and Q655X mutations were expressed in photoreceptor-derived 661W cells with CNGB3 subunits. Compared to wild type, R563H and Q655X subunits displayed altered degradation rates and/or were retained in the ER. ER retention was associated with increased expression of UPR-related markers of ER stress and with decreased cell viability. Chemical and pharmacological chaperones (TUDCA, 4PBA, and the cGMP analog CPT-cGMP) differentially reduced degradation and/or promoted plasma-membrane localization of defective subunits. Improved subunit maturation was concordant with reduced expression of ER stress markers and improved viability of cells expressing localization-defective channels. These results indicate that ER stress can arise from expression of localization defective CNG channels, and may represent a contributing factor for photoreceptor degeneration. PMID:21992067

Defective trafficking of cone photoreceptor CNG channels induces the unfolded protein response and ER-stress-associated cell death.

PubMed

Duricka, Deborah L; Brown, R Lane; Varnum, Michael D

2012-01-15

Mutations that perturb the function of photoreceptor CNG (cyclic nucleotide-gated) channels are associated with several human retinal disorders, but the molecular and cellular mechanisms leading to photoreceptor dysfunction and degeneration remain unclear. Many loss-of-function mutations result in intracellular accumulation of CNG channel subunits. Accumulation of proteins in the ER (endoplasmic reticulum) is known to cause ER stress and trigger the UPR (unfolded protein response), an evolutionarily conserved cellular programme that results in either adaptation via increased protein processing capacity or apoptotic cell death. We hypothesize that defective trafficking of cone photoreceptor CNG channels can induce UPR-mediated cell death. To test this idea, CNGA3 subunits bearing the R563H and Q655X mutations were expressed in photoreceptor-derived 661W cells with CNGB3 subunits. Compared with wild-type, R563H and Q655X subunits displayed altered degradation rates and/or were retained in the ER. ER retention was associated with increased expression of UPR-related markers of ER stress and with decreased cell viability. Chemical and pharmacological chaperones {TUDCA (tauroursodeoxycholate sodium salt), 4-PBA (sodium 4-phenylbutyrate) and the cGMP analogue CPT-cGMP [8-(4-chlorophenylthio)-cGMP]} differentially reduced degradation and/or promoted plasma-membrane localization of defective subunits. Improved subunit maturation was concordant with reduced expression of ER-stress markers and improved viability of cells expressing localization-defective channels. These results indicate that ER stress can arise from expression of localization-defective CNG channels, and may represent a contributing factor for photoreceptor degeneration.

Deficiency in the mitochondrial apoptotic pathway reveals the toxic potential of autophagy under ER stress conditions.

PubMed

Deegan, Shane; Saveljeva, Svetlana; Logue, Susan E; Pakos-Zebrucka, Karolina; Gupta, Sanjeev; Vandenabeele, Peter; Bertrand, Mathieu J M; Samali, Afshin

2014-01-01

Endoplasmic reticulum (ER) stress-induced cell death is normally associated with activation of the mitochondrial apoptotic pathway, which is characterized by CYCS (cytochrome c, somatic) release, apoptosome formation, and caspase activation, resulting in cell death. In this study, we demonstrate that under conditions of ER stress cells devoid of CASP9/caspase-9 or BAX and BAK1, and therefore defective in the mitochondrial apoptotic pathway, still undergo a delayed form of cell death associated with the activation of caspases, therefore revealing the existence of an alternative stress-induced caspase activation pathway. We identified CASP8/caspase-8 as the apical protease in this caspase cascade, and found that knockdown of either of the key autophagic genes, ATG5 or ATG7, impacted on CASP8 activation and cell death induction, highlighting the crucial role of autophagy in the activation of this novel ER stress-induced death pathway. In line with this, we identified a protein complex composed of ATG5, FADD, and pro-CASP8 whose assembly coincides with caspase activation and cell death induction. Together, our results reveal the toxic potential of autophagy in cells undergoing ER stress that are defective in the mitochondrial apoptotic pathway, and suggest a model in which the autophagosome functions as a platform facilitating pro-CASP8 activation. Chemoresistance, a common problem in the treatment of cancer, is frequently caused by the downregulation of key mitochondrial death effector proteins. Alternate stress-induced apoptotic pathways, such as the one described here, may become of particular relevance for tackling the problem of chemoresistance in cancer cells.

GILZ overexpression attenuates endoplasmic reticulum stress-mediated cell death via the activation of mitochondrial oxidative phosphorylation

DOE Office of Scientific and Technical Information (OSTI.GOV)

André, Fanny; Corazao-Rozas, Paola; Idziorek, Thierry

The Glucocorticoïd-induced leucine zipper (GILZ) protein has profound anti-inflammatory activities in haematopoietic cells. GILZ regulates numerous signal transduction pathways involved in proliferation and survival of normal and neoplastic cells. Here, we have demonstrated the potential of GILZ in alleviating apoptosis induced by ER stress inducers. Whereas the glucocorticoid, dexamethasone, protects from tunicamycin-induced cell death, silencing endogeneous GILZ in dexamethasone-treated cancer cells alter the capacity of glucocorticoids to protect from tunicamycin-mediated apoptosis. Under ER stress conditions, overexpression of GILZ significantly reduced activation of mitochondrial pathway of apoptosis by maintaining Bcl-xl level. GILZ protein affects the UPR signaling shifting the balance towardsmore » pro-survival signals as judged by down-regulation of CHOP, ATF4, XBP1s mRNA and increase in GRP78 protein level. Interestingly, GILZ sustains high mitochondrial OXPHOS during ER stress and cytoprotection mediated by GILZ is abolished in cells depleted of mitochondrial DNA, which are OXPHOS-deficient. These findings reveal a new role of GILZ, which acts as a cytoprotector against ER stress through a pathway involving mitochondrial OXPHOS. - Highlights: • GILZ attenuates apoptotic cell death induced by ER stress conditions. • GILZ promotes pro-survival signaling of the UPR. • GILZ overexpression sustains high mitochondrial activity under ER stress. • Mitochondrial OXPHOX is required for GILZ protective effects against ER stress-mediated apoptosis.« less

Endoplasmic Reticulum Stress Aggravates Viral Myocarditis by Raising Inflammation Through the IRE1-Associated NF-κB Pathway.

PubMed

Zha, Xi; Yue, Yan; Dong, Ning; Xiong, Sidong

2015-08-01

Viral myocarditis, which is mostly caused by coxsackievirus infection, is characterized by myocardial inflammation. Abnormal endoplasmic reticulum (ER) stress participates in many heart diseases, but its role in viral myocarditis remains unsolved. We investigated the influence of ER stress in coxsackievirus B3 (CVB3)-induced viral myocarditis by dynamically detecting its activation in CVB3-infected hearts, analyzing its association with myocarditis severity, and exploring its impact on disease development by modulating the strength of ER stress with the chemical activator tunicamycin (Tm) or the inhibitor tauroursodeoxycholic acid (TUDCA). The underlying signal pathway of ER stress in CVB3-induced myocarditis was also deciphered. We found that myocardial expression of Grp78 and Grp94, 2 ER stress markers, was significantly increased after CVB3 infection and positively correlated with myocarditis severity. Consistently, Tm-augmented ER stress obviously aggravated myocarditis, as shown by more severe myocardial inflammation, reduced cardiac function, and a lower survival rate, whereas TUDCA decreased ER stress and obviously alleviated myocarditis. This pathologic effect of ER stress could be attributed to increased levels of proinflammatory cytokine (interleukin [IL]-6, IL-12, tumor necrosis factor-alpha, and monocyte chemoattractant protein-1) production through the IRE1-associated nuclear factor-κB (NF-kB) pathway. ER stress accentuated CVB3-induced myocardial inflammation through the IRE1-associated NF-κB pathway. This study may help us understand the role of ER stress in viral myocarditis and promote the development of corresponding therapeutic strategies based on manipulating ER stress. Copyright © 2015 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Experimental reconstitution of chronic ER stress in the liver reveals feedback suppression of BiP mRNA expression

PubMed Central

Gomez, Javier A; Rutkowski, D Thomas

2016-01-01

Endoplasmic reticulum (ER) stress is implicated in many chronic diseases, but very little is known about how the unfolded protein response (UPR) responds to persistent ER stress in vivo. Here, we experimentally reconstituted chronic ER stress in the mouse liver, using repeated injection of a low dose of the ER stressor tunicamycin. Paradoxically, this treatment led to feedback-mediated suppression of a select group of mRNAs, including those encoding the ER chaperones BiP and GRP94. This suppression was due to both silencing of the ATF6α pathway of UPR-dependent transcription and enhancement of mRNA degradation, possibly via regulated IRE1-dependent decay (RIDD). The suppression of mRNA encoding BiP was phenocopied by ectopic overexpression of BiP protein, and was also observed in obese mice. Our findings suggest that persistent cycles of UPR activation and deactivation create an altered, quasi-stable setpoint for UPR-dependent transcriptional regulation—an outcome that could be relevant to conditions such as metabolic syndrome. DOI: http://dx.doi.org/10.7554/eLife.20390.001 PMID:27938665

Shikonin ameliorates isoproterenol (ISO)-induced myocardial damage through suppressing fibrosis, inflammation, apoptosis and ER stress.

PubMed

Yang, Jun; Wang, Zhao; Chen, Dong-Lin

2017-09-01

Shikonin, isolated from the roots of herbal plant Lithospermum erythrorhizon, is a naphthoquinone. It has been reported to exert beneficial anti-inflammatory effects and anti-oxidant properties in various diseases. Isoproterenol (ISO) has been widely used to establish cardiac injury in vivo and in vitro. However, shikonin function in ISO-induced cardiac injury remains uncertain. In our study, we attempted to investigate the efficiency and possible molecular mechanism of shikonin in cardiac injury treatment induced by ISO. In vivo, C57BL6 mice were subcutaneously injected with 5mg/kg ISO to induce heart failure. And mice were given a gavage of shikonin (2 or 4mg/kg/d, for four weeks). Cardiac function, fibrosis indices, inflammation response, apoptosis and endoplasmic reticulum (ER) stress were calculated. Pathological alterations, fibrosis-, inflammation-, apoptosis- and ER stress-related molecules were examined. In ISO-induced cardiac injury, shikonin significantly ameliorated heart function, decreased myocardial fibrosis, suppressed inflammation, attenuated apoptosis and ER stress through impeding collagen accumulation, Toll like receptor 4/nuclear transcription factor κB (TLR4/NF-κB), Caspase-3 and glucose-regulated protein 78 (GRP78) signaling pathways activity, relieving heart failure in vivo. Also, in vitro, shikonin attenuated ISO-induced cardiac muscle cells by reducing fibrosis, inflammation, apoptosis and ER stress. Our findings indicated that shikonin treatment attenuated ISO-induced heart injury, providing an effective therapeutic strategy for heart failure treatment for future. Copyright © 2017. Published by Elsevier Masson SAS.

Impaired autophagy activity is linked to elevated ER-stress and inflammation in aging adipose tissue

PubMed Central

Ghosh, Amiya Kumar; Mau, Theresa; O'Brien, Martin; Garg, Sanjay; Yung, Raymond

2016-01-01

Adipose tissue dysfunction in aging is associated with inflammation, metabolic syndrome and other diseases. We propose that impaired protein homeostasis due to compromised lysosomal degradation (micro-autophagy) might promote aberrant ER stress response and inflammation in aging adipose tissue. Using C57BL/6 mouse model, we demonstrate that adipose tissue-derived stromal vascular fraction (SVF) cells from old (18-20 months) mice have reduced expression of autophagy markers as compared to the younger (4-6 months) cohort. Elevated expressions of ER-stress marker CHOP and autophagy substrate SQSTM1/p62 are observed in old SVFs compared to young, when treated with either vehicle or with thapsigargin (Tg), an ER stress inducer. Treatment with bafilomycin A1 (Baf), a vacuolar-type H (+)-ATPase, or Tg elevated expressions of CHOP, and SQSTM1/p62 and LC-3-II, in 3T3-L1-preadipocytes. We also demonstrate impaired autophagy activity in old SVFs by analyzing increased accumulation of autophagy substrates LC3-II and p62. Compromised autophagy activity in old SVFs is correlated with enhanced release of pro-inflammatory cytokines IL-6 and MCP-1. Finally, SVFs from calorie restricted old mice (CR-O) have shown enhanced autophagy activity compared to ad libitum fed old mice (AL-O). Our results support the notion that diminished autophagy activity with aging contributes to increased adipose tissue ER stress and inflammation. PMID:27777379

Protective effect of catechin in type I Gaucher disease cells by reducing endoplasmic reticulum stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Yea-Jin; Kim, Sung-Jo, E-mail: sungjo@hoseo.edu; Heo, Tae-Hwe, E-mail: thhur92@catholic.ac.kr

Highlights: {yields} Catechin reduces the expression level of ER stress marker protein in type I Gaucher disease cells. {yields} Catechin induces the proliferation rate of GD cells similar levels to normal cells. {yields} Catechin improves wound healing activity. {yields} Catechin-mediated reductions in ER stress may be associated with enhanced cell survival. {yields} We identified catechin as a protective agent against ER stress in GD cells. -- Abstract: Gaucher disease (GD) is the most common lysosomal storage disorder (LSD) and is divided into three phenotypes, I, II, and III. Type I is the most prevalent form and has its onset inmore » adulthood. The degree of endoplasmic reticulum (ER) stress is one of the factors that determine GD severity. It has recently been reported that antioxidants reduce ER stress and apoptosis by scavenging the oxidants that cause oxidative stress. For this report, we investigated the possibility that catechin can act on type I GD patient cells to alleviate the pathogenic conditions of GD. We treated GD cells with catechin and examined the expression level of GRP78/BiP (an ER stress marker) by western blots and fluorescence microscopy, the proliferation rate of GD cells, and scratch-induced wound healing activity. Our results show that catechin reduces the expression level of GRP78/BiP, leads to cell proliferation rates of GD cells similar levels to normal cells, and improves wound healing activity. We conclude that catechin protects against ER stress in GD cells and catechin-mediated reductions in ER stress may be associated with enhanced cell survival.« less

Simvastatin inhibits ox-LDL-induced inflammatory adipokines secretion via amelioration of ER stress in 3T3-L1 adipocyte.

PubMed

Wu, Zhi-hong; Chen, Ya-qin; Zhao, Shui-ping

2013-03-08

Adipocytes behave as a rich source of pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein 1 (MCP-1). Endoplasmic reticulum (ER) stress in adipocytes can alter adipokines secretion and induce inflammation. The aim of this study is to evaluate the effect of simvastatin on the ox-LDL-induced ER stress and expression and secretion of TNF-α and MCP-1 in 3T3-L1 adipocytes. Differentiated adipocytes were treated with various concentrations of ox-LDL (0-100 μg/ml) for 24h with or without simvastatin pre-treatment. The protein expressions of ER stress markers, glucose-regulated protein 78 (GRP78) and C/EBP homology protein (CHOP), were determined by Western blot analysis. The mRNA expressions of TNF-α and MCP-1 were measured by real-time PCR. The protein release of TNF-α and MCP-1 in culture medium were evaluated by ELISA. Ox-LDL treatment led to significant up-regulation of GRP78 and CHOP in dose-dependent manner. The expressions of TNF-α and MCP-1 were dose-dependently increased at mRNA and protein levels after ox-LDL intervention. The effects of ox-LDL on adipocytes were abolished by pre-treatment with 4-phenylbutyrate (4-PBA), a chemical chaperone known to ameliorate ER stress. Simvastatin could inhibit ox-LDL-induced ER stress and reduce the expression of TNF-α and MCP-1 at mRNA and protien level in dose dependent manner. In conclusion, ox-LDL can stimulate the expression and secretion of TNF-α and MCP-1 through its activation of ER stress in adipocytes. Simvastatin might exert direct anti-inflammatory effects in adipocytes through amelioration of ER stress. Copyright © 2013 Elsevier Inc. All rights reserved.

Salubrinal and robenacoxib treatment after global cerebral ischemia. Exploring the interactions between ER stress and inflammation.

PubMed

Anuncibay-Soto, Berta; Pérez-Rodriguez, Diego; Santos-Galdiano, María; Font-Belmonte, Enrique; Ugidos, Irene F; Gonzalez-Rodriguez, Paloma; Regueiro-Purriños, Marta; Fernández-López, Arsenio

2018-05-01

Blood reperfusion of the ischemic tissue after stroke promotes increases in the inflammatory response as well as accumulation of unfolded/misfolded proteins in the cell, leading to endoplasmic reticulum (ER) stress. Both Inflammation and ER stress are critical processes in the delayed death of the cells damaged after ischemia. The aim of this study is to check the putative synergic neuroprotective effect by combining anti-inflammatory and anti-ER stress agents after ischemia. The study was performed on a two-vessel occlusion global cerebral ischemia model. Animals were treated with salubrinal one hour after ischemia and with robenacoxib at 8 h and 32 h after ischemia. Parameters related to the integrity of the blood-brain barrier (BBB), such as matrix metalloproteinase 9 and different cell adhesion molecules (CAMs), were analyzed by qPCR at 24 h and 48 h after ischemia. Microglia and cell components of the neurovascular unit, including neurons, endothelial cells and astrocytes, were analyzed by immunofluorescence after 48 h and seven days of reperfusion. Pharmacologic control of ER stress by salubrinal treatment after ischemia, revealed a neuroprotective effect over neurons that reduces the transcription of molecules involved in the impairment of the BBB. Robenacoxib treatment stepped neuronal demise forward, revealing a detrimental effect of this anti-inflammatory agent. Combined treatment with robenacoxib and salubrinal after ischemia prevented neuronal loss and changes in components of the neurovascular unit and microglia observed when animals were treated only with robenacoxib. Combined treatment with anti-ER stress and anti-inflammatory agents is able to provide enhanced neuroprotective effects reducing glial activation, which opens new avenues in therapies against stroke. Copyright © 2018 Elsevier Inc. All rights reserved.

Morbillivirus Glycoprotein Expression Induces ER Stress, Alters Ca2+ Homeostasis and Results in the Release of Vasostatin

PubMed Central

Doucey, Marie-Agnès; Rosso, Lia; Curie, Thomas; Montagner, Alexandra; Wittek, Riccardo; Vandelvelde, Marc; Zurbriggen, Andreas; Hirling, Harald; Desvergne, Béatrice

2012-01-01

Although the pathology of Morbillivirus in the central nervous system (CNS) is well described, the molecular basis of neurodegenerative events still remains poorly understood. As a model to explore Morbillivirus-mediated CNS dysfunctions, we used canine distemper virus (CDV) that we inoculated into two different cell systems: a monkey cell line (Vero) and rat primary hippocampal neurons. Importantly, the recombinant CDV used in these studies not only efficiently infects both cell types but recapitulates the uncommon, non-cytolytic cell-to-cell spread mediated by virulent CDVs in brain of dogs. Here, we demonstrated that both CDV surface glycoproteins (F and H) markedly accumulated in the endoplasmic reticulum (ER). This accumulation triggered an ER stress, characterized by increased expression of the ER resident chaperon calnexin and the proapoptotic transcription factor CHOP/GADD 153. The expression of calreticulin (CRT), another ER resident chaperon critically involved in the response to misfolded proteins and in Ca2+ homeostasis, was also upregulated. Transient expression of recombinant CDV F and H surface glycoproteins in Vero cells and primary hippocampal neurons further confirmed a correlation between their accumulation in the ER, CRT upregulation, ER stress and disruption of ER Ca2+ homeostasis. Furthermore, CDV infection induced CRT fragmentation with re-localisation of a CRT amino-terminal fragment, also known as vasostatin, on the surface of infected and neighbouring non-infected cells. Altogether, these results suggest that ER stress, CRT fragmentation and re-localization on the cell surface may contribute to cytotoxic effects and ensuing cell dysfunctions triggered by Morbillivirus, a mechanism that might potentially be relevant for other neurotropic viruses. PMID:22403712

Exploring the cross talk between ER stress and inflammation in age-related macular degeneration.

PubMed

Kheitan, Samira; Minuchehr, Zarrin; Soheili, Zahra-Soheila

2017-01-01

Increasing evidence demonstrates that inflammation and endoplasmic reticulum (ER) stress is implicated in the development and progression of age-related macular degeneration (AMD), a multifactorial neurodegenerative disease. However the cross talk between these cellular mechanisms has not been clearly and fully understood. The present study investigates a possible intersection between ER stress and inflammation in AMD. In this study, we recruited two collections of involved protein markers to retrieve their interaction information from IMEx-curated databases, which are the most well- known protein-protein interaction collections, allowing us to design an intersection network for AMD that is unprecedented. In order to find expression activated subnetworks, we utilized AMD expression profiles in our network. In addition, we studied topological characteristics of the most expressed active subnetworks to identify the hubs. With regard to topological quantifications and expressional activity, we reported a list of the most pivotal hubs which are potentially applicable as probable therapeutic targets. Furthermore, we introduced MAPK signaling pathway as a significantly involved pathway in the association between ER stress and inflammation, leading to promising new directions in discovering AMD formation mechanisms and possible treatments.

Exploring the cross talk between ER stress and inflammation in age-related macular degeneration

PubMed Central

Kheitan, Samira; Soheili, Zahra-Soheila

2017-01-01

Increasing evidence demonstrates that inflammation and endoplasmic reticulum (ER) stress is implicated in the development and progression of age-related macular degeneration (AMD), a multifactorial neurodegenerative disease. However the cross talk between these cellular mechanisms has not been clearly and fully understood. The present study investigates a possible intersection between ER stress and inflammation in AMD. In this study, we recruited two collections of involved protein markers to retrieve their interaction information from IMEx-curated databases, which are the most well- known protein-protein interaction collections, allowing us to design an intersection network for AMD that is unprecedented. In order to find expression activated subnetworks, we utilized AMD expression profiles in our network. In addition, we studied topological characteristics of the most expressed active subnetworks to identify the hubs. With regard to topological quantifications and expressional activity, we reported a list of the most pivotal hubs which are potentially applicable as probable therapeutic targets. Furthermore, we introduced MAPK signaling pathway as a significantly involved pathway in the association between ER stress and inflammation, leading to promising new directions in discovering AMD formation mechanisms and possible treatments. PMID:28742151

Endoplasmic reticulum turnover: ER-phagy and other flavors in selective and non-selective ER clearance.

PubMed

Fregno, Ilaria; Molinari, Maurizio

2018-01-01

The endoplasmic reticulum (ER) is a highly dynamic organelle in eukaryotic cells. It is deputed to lipid and protein biosynthesis, calcium storage, and the detoxification of various exogenous and endogenous harmful compounds. ER activity and size must be adapted rapidly to environmental and developmental conditions or biosynthetic demand. This is achieved on induction of thoroughly studied transcriptional/translational programs defined as "unfolded protein responses" that increase the ER volume and the expression of ER-resident proteins regulating the numerous ER functions. Less understood are the lysosomal catabolic processes that maintain ER size at steady state, that prevent excessive ER expansion during ER stresses, or that ensure return to physiologic ER size during recovery from ER stresses. These catabolic processes may also be activated to remove ER subdomains where proteasome-resistant misfolded proteins or damaged lipids have been segregated. Insights into these catabolic mechanisms have only recently emerged with the identification of so-called ER-phagy receptors, which label specific ER subdomains for selective lysosomal delivery for clearance. Here, in eight chapters and one addendum, we comment on recent advances in ER turnover pathways induced by ER stress, nutrient deprivation, misfolded proteins, and live bacteria. We highlight the role of yeast (Atg39 and Atg40) and mammalian (FAM134B, SEC62, RTN3, and CCPG1) ER-phagy receptors and of autophagy genes in selective and non-selective catabolic processes that regulate cellular proteostasis by controlling ER size, turnover, and function.

Parasite-induced ER stress response in hepatocytes facilitates Plasmodium liver stage infection

PubMed Central

Inácio, Patricia; Zuzarte-Luís, Vanessa; Ruivo, Margarida TG; Falkard, Brie; Nagaraj, Nagarjuna; Rooijers, Koos; Mann, Matthias; Mair, Gunnar; Fidock, David A; Mota, Maria M

2015-01-01

Upon infection of a mammalian host, Plasmodium parasites first replicate inside hepatocytes, generating thousands of new parasites. Although Plasmodium intra-hepatic development represents a substantial metabolic challenge to the host hepatocyte, how infected cells respond to and integrate this stress remains poorly understood. Here, we present proteomic and transcriptomic analyses, revealing that the endoplasmic reticulum (ER)-resident unfolded protein response (UPR) is activated in host hepatocytes upon Plasmodium berghei infection. The expression of XBP1s—the active form of the UPR mediator XBP1—and the liver-specific UPR mediator CREBH is induced by P. berghei infection in vivo. Furthermore, this UPR induction increases parasite liver burden. Altogether, our data suggest that ER stress is a central feature of P. berghei intra-hepatic development, contributing to the success of infection. PMID:26113366

Calnexin, an ER stress-induced protein, is a prognostic marker and potential therapeutic target in colorectal cancer.

PubMed

Ryan, Deborah; Carberry, Steven; Murphy, Áine C; Lindner, Andreas U; Fay, Joanna; Hector, Suzanne; McCawley, Niamh; Bacon, Orna; Concannon, Caoimhin G; Kay, Elaine W; McNamara, Deborah A; Prehn, Jochen H M

2016-07-01

Colorectal cancer (CRC) is a leading cause of cancer mortality in the Western world and commonly treated with genotoxic chemotherapy. Stress in the endoplasmic reticulum (ER) was implicated to contribute to chemotherapeutic resistance. Hence, ER stress related protein may be of prognostic or therapeutic significance. The expression levels of ER stress proteins calnexin, calreticulin, GRP78 and GRP94 were determined in n = 23 Stage II and III colon cancer fresh frozen tumour and matched normal tissue samples. Data were validated in a cohort of n = 11 rectal cancer patients treated with radiochemotherapy in the neoadjuvant setting. The calnexin gene was silenced using siRNA in HCT116 cells. There were no increased levels of ER stress proteins in tumour compared to matched normal tissue samples in Stage II or III CRC. However, increased calnexin protein levels were predictive of poor clinical outcome in the patient cohort. Data were validated in the rectal cancer cohort treated in the neoadjuvant setting. Calnexin gene-silencing significantly reduced cell survival and increased cancer cell susceptibility to 5FU chemotherapy. Increased tumour protein levels of calnexin may be of prognostic significance in CRC, and calnexin may represent a potential target for future therapies.

Lipopolysaccharide-Induced Behavioral Alterations Are Alleviated by Sodium Phenylbutyrate via Attenuation of Oxidative Stress and Neuroinflammatory Cascade.

PubMed

Jangra, Ashok; Sriram, Chandra Shaker; Lahkar, Mangala

2016-08-01

Oxido-nitrosative stress, neuroinflammation, and reduced level of neurotrophins are implicated in the pathophysiology of anxiety and depressive illness. A few recent studies have revealed the role of endoplasmic reticulum (ER) stress in the pathophysiology of stress and depression. The aim of the present study is to investigate the neuroprotective potential of sodium phenylbutyrate (SPB), an ER stress inhibitor against lipopolysaccharide (LPS)-induced anxiety and depressive-like behavior in Swiss albino mice. Anxiety and depressive-like behavior was induced by LPS (0.83 mg/kg; i.p.) administration. Various behavioral tests were conducted to evaluate the anxiety and depressive-like behavior in mice. Real-time PCR was employed for the detection and expression of ER stress markers (78-kDa glucose-regulated protein (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP)). Pretreatment with SPB significantly ameliorated the LPS-induced anxiety and depressive-like behavior as revealed by behavioral paradigm results. LPS-induced oxidative stress was ameliorated by SPB pretreatment in hippocampus (HC) and prefrontal cortex (PFC) region. Neuroinflammation was significantly reduced by SPB pretreatment in LPS-treated mice as evident from reduction in proinflammatory cytokines (IL-1β and TNF-α). Importantly, LPS administration significantly up-regulated the GRP78 mRNA expression level in the HC which suggests the involvement of unfolded protein response (UPR) in LPS-evoked behavioral anomalies. These results highlight the neuroprotective potential of SPB in LPS-induced anxiety and depressive illness model which may be partially due to inhibition of oxidative stress-neuroinflammatory cascade.

MCP-1 causes cardiomyoblast death via autophagy resulting from ER stress caused by oxidative stress generated by inducing a novel zinc-finger protein, MCPIP.

PubMed

Younce, Craig W; Kolattukudy, Pappachan E

2010-01-27

MCP-1 (monocyte chemotactic protein-1) plays a critical role in the development of heart failure that is known to involve apoptosis. How MCP-1 contributes to cell death involved in the development of heart disease is not understood. In the present study we show that MCP-1 causes death in cardiac myoblasts, H9c2 cells, by inducing oxidative stress which causes ER stress leading to autophagy via a novel zinc-finger protein, MCPIP (MCP-1-induced protein). MCPIP expression caused cell death, and knockdown of MCPIP attenuated MCP-1-induced cell death. It caused induction of iNOS (inducible NO synthase), translocation of the NADPH oxidase subunit phox47 from the cytoplasm to the membrane, production of ROS (reactive oxygen species), and induction of ER (endoplasmic reticulum) stress markers HSP40 (heat-shock protein 40), PDI (protein disulfide-isomerase), GRP78 (guanine-nucleotide-releasing protein 78) and IRE1alpha (inositol-requiring enzyme 1alpha). It also caused autophagy, as indicated by beclin-1 induction, cleavage of LC3 (microtubule-associated protein 1 light chain 3) and autophagolysosome formation, and apoptosis, as indicated by caspase 3 activation and TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP nick-end labelling) assay. Inhibitors of oxidative stress, including CeO2 nanoparticles, inhibited ROS formation, ER stress, autophagy and cell death. Specific inhibitors of ER stress inhibited autophagy and cell death as did knockdown of the ER stress signalling protein IRE1. Knockdown of beclin-1 and autophagy inhibitors prevented cell death. This cell death involved caspase 2 and caspase 12, as specific inhibitors of these caspases prevented MCPIP-induced cell death. Microarray analysis showed that MCPIP expression caused induction of a variety of genes known to be involved in cell death. MCPIP caused activation of JNK (c-Jun N-terminal kinase) and p38 and induction of p53 and PUMA (p53 up-regulated modulator of apoptosis). Taken together, these

Globular adiponectin protects rat hepatocytes against acetaminophen-induced cell death via modulation of the inflammasome activation and ER stress: Critical role of autophagy induction.

PubMed

Kim, Eun Hye; Park, Pil-Hoon

2018-05-24

Acetaminophen (APAP) overdose treatment causes severe liver injury. Adiponectin, a hormone predominantly produced by adipose tissue, exhibits protective effects against APAP-induced hepatotoxicity. However, the underlying mechanisms are not clearly understood. In the present study, we examined the protective effect of globular adiponectin (gAcrp) on APAP-induced hepatocyte death and its underlying mechanisms. We found that APAP (2 mM)-induced hepatocyte death was prevented by inhibition of the inflammasome. In addition, treatment with gAcrp (0.5 and 1 μg/ml) inhibited APAP-induced activation of the inflammasome, judged by suppression of interleukin-1β maturation, caspase-1 activation, and apoptosis-associated speck-like protein (ASC) speck formation, suggesting that protective effects of gAcrp against APAP-induced hepatocyte death is mediated via modulation of the inflammasome. APAP also induced ER stress and treatment with tauroursodeoxycholic acid (TUDCA), an ER chaperone and inhibitor of ER stress, abolished APAP-induced inflammasomes activation, implying that ER stress acts as signaling event leading to the inflammasome activation in hepatocytes stimulated with APAP. Moreover, gAcrp significantly suppressed APAP-induced expression of ER stress marker genes. Finally, the modulatory effects of gAcrp on ER stress and inflammasomes activation were abrogated by treatment with autophagy inhibitors, while an autophagy inducer (rapamycin) suppressed APAP-elicited ER stress, demonstrating that autophagy induction plays a crucial role in the suppression of APAP-induced inflammasome activation and ER stress by gAcrp. Taken together, these results indicate that gAcrp protects hepatocytes against APAP-induced cell death by modulating ER stress and the inflammasome activation, at least in part, via autophagy induction. Copyright © 2018. Published by Elsevier Inc.

Valsartan Protects Against Contrast-Induced Acute Kidney Injury in Rats by Inhibiting Endoplasmic Reticulum Stress-Induced Apoptosis.

PubMed

Sun, Yan; Peng, Ping-An; Ma, Yue; Liu, Xiao-Li; Yu, Yi; Jia, Shuo; Xu, Xiao-Han; Wu, Si-Jing; Zhou, Yu-Jie

2017-01-01

Contrast-induced acute kidney injury (CI-AKI) is a serious complication of the administration of iodinated contrast media (CM) for diagnostic and interventional cardiovascular procedures and is associated with substantial morbidity and mortality. While the preventative measures can mitigate the risk of CI-AKI, there remains a need for novel and effective therapeutic approaches. The pathogenesis of CI-AKI is complex and not completely understood. CM-induced renal tubular cell apoptosis caused by the activation of endoplasmic reticulum (ER) stress is involved in CIAKI. We previously demonstrated that valsartan alleviated CM-induced human renal tubular cell apoptosis by inhibiting ER stress in vitro. However, the nephroprotective effect of valsartan on CI-AKI in vivo has not been investigated. Therefore, the aim of this study was to explore the protective effect of valsartan in a rat model of CI-AKI by measuring the amelioration of renal damage and the changes in ER stressrelated biomarkers. Our results showed that the radiocontrast agent meglumine diatrizoate caused significant renal insufficiency, renin-angiotensin system (RAS) activation, and renal tubular apoptosis by triggering ER stress through activation of glucose-regulated protein 78 (GRP78), activating transcription factor 4 (ATF4), caspase 12, CCAAT/enhancer-binding protein-homologous protein (CHOP) and c-Jun N-terminal protein kinase (JNK) (P<0.05; n=6 in each group). Pre-treatment with valsartan significantly alleviated renal dysfunction, pathological injury, and apoptosis along with the inhibition of ER stressrelated biomarkers (P<0.05; n=8 in each group). Valsartan could protect against meglumine diatrizoate-induced kidney injury in rats by inhibiting the ER stress-induced apoptosis, making it a promising strategy for preventing CI-AKI. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Haem oxygenase-1 is involved in salicylic acid-induced alleviation of oxidative stress due to cadmium stress in Medicago sativa

PubMed Central

Shen, Wenbiao

2012-01-01

This work examines the involvement of haem oxygenase-1 (HO-1) in salicylic acid (SA)-induced alleviation of oxidative stress as a result of cadmium (Cd) stress in alfalfa (Medicago sativa L.) seedling roots. CdCl2 exposure caused severe growth inhibition and Cd accumulation, which were potentiated by pre-treatment with zinc protoporphyrin (ZnPPIX), a potent HO-1 inhibitor. Pre-treatment of plants with the HO-1 inducer haemin or SA, both of which could induce MsHO1 gene expression, significantly reduced the inhibition of growth and Cd accumulation. The alleviation effects were also evidenced by a decreased content of thiobarbituric acid-reactive substances (TBARS). The antioxidant behaviour was confirmed by histochemical staining for the detection of lipid peroxidation and the loss of plasma membrane integrity. Furthermore, haemin and SA pre-treatment modulated the activities of ascorbate peroxidase (APX), superoxide dismutase (SOD), and guaiacol peroxidase (POD), or their corresponding transcripts. Significant enhancement of the ratios of reduced/oxidized homoglutathione (hGSH), ascorbic acid (ASA)/dehydroascorbate (DHA), and NAD(P)H/NAD(P)+, and expression of their metabolism genes was observed, consistent with a decreased reactive oxygen species (ROS) distribution in the root tips. These effects are specific for HO-1, since ZnPPIX blocked the above actions, and the aggravated effects triggered by SA plus ZnPPIX were differentially reversed when carbon monoxide (CO) or bilirubin (BR), two catalytic by-products of HO-1, was added. Together, the results suggest that HO-1 is involved in the SA-induced alleviation of Cd-triggered oxidative stress by re-establishing redox homeostasis. PMID:22915740

Critical role of endogenous Akt/IAPs and MEK1/ERK pathways in counteracting endoplasmic reticulum stress-induced cell death.

PubMed

Hu, Ping; Han, Zhang; Couvillon, Anthony D; Exton, John H

2004-11-19

Endoplasmic reticulum (ER) stress has been implicated in the pathogenesis of many diseases and in cancer therapy. Although the unfolded protein response is known to alleviate ER stress by reducing the accumulation of misfolded proteins, the exact survival elements and their downstream signaling pathways that directly counteract ER stress-stimulated apoptotic signaling remain elusive. Here, we have shown that endogenous Akt and ERK are rapidly activated and act as downstream effectors of phosphatidylinositol 3-kinase in thapsigargin- or tunicamycin-induced ER stress. Introduction of either dominant-negative Akt or MEK1 or the inhibitors LY294002 and U0126 sensitized cells to ER stress-induced cell death in different cell types. Reverse transcription-PCR analysis of gene expression during ER stress revealed that cIAP-2 and XIAP, members of the IAP family of potent caspase suppressors, were strongly induced. Transcription of cIAP-2 and XIAP was up-regulated by the phosphatidylinositol 3-kinase/Akt pathway as shown by its reversal by dominant-negative Akt or LY294002. Ablation of these IAPs by RNA interference sensitized cells to ER stress-induced death, which was reversed by the caspase inhibitor benzyloxycarbonyl-VAD-fluoromethyl ketone. The protective role of IAPs in ER stress coincided with Smac release from mitochondria to the cytosol. Furthermore, it was shown that mTOR was not required for Akt-mediated survival. These results represent the first demonstration that activation of endogenous Akt/IAPs and MEK/ERK plays a critical role in controlling cell survival by resisting ER stress-induced cell death signaling.

A sphingolipid-dependent diffusion barrier confines ER stress to the yeast mother cell

PubMed Central

Clay, Lori; Caudron, Fabrice; Denoth-Lippuner, Annina; Boettcher, Barbara; Buvelot Frei, Stéphanie; Snapp, Erik Lee; Barral, Yves

2014-01-01

In many cell types, lateral diffusion barriers compartmentalize the plasma membrane and, at least in budding yeast, the endoplasmic reticulum (ER). However, the molecular nature of these barriers, their mode of action and their cellular functions are unclear. Here, we show that misfolded proteins of the ER remain confined into the mother compartment of budding yeast cells. Confinement required the formation of a lateral diffusion barrier in the form of a distinct domain of the ER-membrane at the bud neck, in a septin-, Bud1 GTPase- and sphingolipid-dependent manner. The sphingolipids, but not Bud1, also contributed to barrier formation in the outer membrane of the dividing nucleus. Barrier-dependent confinement of ER stress into the mother cell promoted aging. Together, our data clarify the physical nature of lateral diffusion barriers in the ER and establish the role of such barriers in the asymmetric segregation of proteotoxic misfolded proteins during cell division and aging. DOI: http://dx.doi.org/10.7554/eLife.01883.001 PMID:24843009

Application of bacteria from non-cultivated plants to promote growth, alter root architecture and alleviate salt stress of cotton.

PubMed

Irizarry, I; White, J F

2017-04-01

Cotton seeds are frequently treated with acid to remove fibres and reduce seed-transmitted diseases. This process also eliminates beneficial bacteria on the seed surface. The goal of this research was to seek and apply beneficial bacteria to acid delinted cotton seeds to evaluate their growth-promoting and salt stress alleviating effects in seedlings. Bacteria were isolated from non-cultivated plants in the Malvaceae. Seeds were collected from Portia tree (Thespesia populnea) and wild cotton (Gossypium hirsutum) from coastal and arid areas of Puerto Rico. Bacillus amyloliquefaciens, Curtobacterium oceanosedimentum and Pseudomonas oryzihabitans were inoculated onto acid delinted cotton seeds. Bacteria increased cotton seed germination and length of emerging seedling radicles. Cotton seeds were inoculated with B. amyloliquefaciens to evaluate growth and root architecture of non-stressed and salt stressed seedlings. Inoculating cotton seeds with B. amyloliquefaciens led to a greater percentage of seedlings with expanded cotyledons after 8 days, enhanced primary and lateral root growth, and altered root architecture. Similar results were obtained when okra seeds were inoculated with B. amyloliquefaciens. The data supported the hypothesis that non-cultivated plants in the Malvaceae growing in stressful environments possess bacteria that promote growth, alter root architecture and alleviate salt stress of cotton and okra seedlings. This study demonstrated the effects of applying beneficial bacteria on acid delinted cotton seeds. Inoculating seeds with salt stress alleviating bacteria could improve the growth of crop seedlings that are vulnerable to soil salinization. © 2017 The Society for Applied Microbiology.

ER stress responses in the absence of apoptosome: a comparative study in CASP9 proficient vs deficient mouse embryonic fibroblasts.

PubMed

Deegan, Shane; Saveljeva, Svetlana; Gupta, Sanjeev; MacDonald, David C; Samali, Afshin

2014-08-29

Cells respond to endoplasmic reticulum (ER) stress through the unfolded protein response (UPR), autophagy and cell death. In this study we utilized casp9(+/+) and casp9(-/-) MEFs to determine the effect of inhibition of mitochondrial apoptosis pathway on ER stress-induced-cell death, UPR and autophagy. We observed prolonged activation of UPR and autophagy in casp9(-/-) cells as compared with casp9(+/+) MEFs, which displayed transient activation of both pathways. Furthermore we showed that while casp9(-/-) MEFs were resistant to ER stress, prolonged exposure led to the activation of a non-canonical, caspase-mediated mode of cell death. Copyright © 2014 Elsevier Inc. All rights reserved.

Longitudinal monitoring of Gaussia and Nano luciferase activities to concurrently assess ER calcium homeostasis and ER stress in vivo.

PubMed

Wires, Emily S; Henderson, Mark J; Yan, Xiaokang; Bäck, Susanne; Trychta, Kathleen A; Lutrey, Molly H; Harvey, Brandon K

2017-01-01

The endoplasmic reticulum (ER) is essential to many cellular processes including protein processing, lipid metabolism and calcium storage. The ability to longitudinally monitor ER homeostasis in the same organism would offer insight into progressive molecular and cellular adaptations to physiologic or pathologic states, but has been challenging. We recently described the creation of a Gaussia luciferase (GLuc)-based secreted ER calcium-modulated protein (SERCaMP or GLuc-SERCaMP) to longitudinally monitor ER calcium homeostasis. Here we describe a complementary tool to measure the unfolded protein response (UPR), utilizing a UPRE-driven secreted Nano luciferase (UPRE-secNLuc) to examine the activating transcription factor-6 (ATF6) and inositol-requiring enzyme 1 (IRE1) pathways of the UPR. We observed an upregulation of endogenous ATF6- and XBP1-regulated genes following pharmacologically-induced ER stress that was consistent with responsiveness of the UPRE sensor. Both GLuc and NLuc-based reporters have favorable properties for in vivo studies, however, they are not easily used in combination due to overlapping substrate activities. We describe a method to measure the enzymatic activities of both reporters from a single sample and validated the approach using culture medium and rat blood samples to measure GLuc-SERCaMP and UPRE-secNLuc. Measuring GLuc and NLuc activities from the same sample allows for the robust and quantitative measurement of two cellular events or cell populations from a single biological sample. This study is the first to describe the in vivo measurement of UPRE activation by sampling blood, using an approach that allows concurrent interrogation of two components of ER homeostasis.

Periodontal disease level-butyric acid amounts locally administered in the rat gingival mucosa induce ER stress in the systemic blood.

PubMed

Cueno, Marni E; Saito, Yuko; Ochiai, Kuniyasu

2016-05-01

Periodontal diseases have long been postulated to contribute to systemic diseases and, likewise, it has been proposed that periodontal disease treatment may ameliorate certain systemic diseases. Short-chain fatty acids (SCFA) are major secondary metabolites produced by oral anaerobic bacteria and, among the SCFAs, butyric acid (BA) in high amounts contribute to periodontal disease development. Periodontal disease level-butyric acid (PDL-BA) is found among patients suffering from periodontal disease and has previously shown to induce oxidative stress, whereas, oxidative stress is correlated to endoplasmic reticulum (ER) stress. This would imply that PDL-BA may likewise stimulate ER stress, however, this was never elucidated. A better understanding of the correlation between PDL-BA and systemic ER stress stimulation could shed light on the possible systemic effects of PDL-BA-related periodontal diseases. Here, PDL-BA was injected into the gingival mucosa and the systemic blood obtained from the rat jugular was collected at 0, 15, 60, and 180 min post-injection. Collected blood samples were purified and only the blood cytosol was used throughout this study. Subsequently, we measured blood cytosolic GADD153, Ca(2+), representative apoptotic and inflammatory caspases, and NF-κB amounts. We found that PDL-BA presence increased blood cytosolic GADD153 and Ca(2+) amounts. Moreover, we observed that blood cytosolic caspases and NF-κB were activated only at 60 and 180 min post-injection in the rat gingival mucosa. This suggests that PDL-BA administered through the gingival mucosa may influence the systemic blood via ER stress stimulation and, moreover, prolonged PDL-BA retention in the gingival mucosa may play a significant role in ER stress-related caspase and NF-κB activation. In a periodontal disease scenario, we propose that PDL-BA-related ER stress stimulation leading to the simultaneous activation of apoptosis and inflammation may contribute to periodontal disease

Taurine ameliorated homocysteine-induced H9C2 cardiomyocyte apoptosis by modulating endoplasmic reticulum stress.

PubMed

Zhang, Zhimin; Zhao, Lianyou; Zhou, Yanfen; Lu, Xuanhao; Wang, Zhengqiang; Wang, Jipeng; Li, Wei

2017-05-01

Homocysteine (Hcy)-triggered endoplasmic reticulum (ER) stress-mediated endothelial cell apoptosis has been suggested as a cause of Hcy-dependent vascular injury. However, whether ER stress is the molecular mechanism linking Hcy and cardiomyocytes death is unclear. Taurine has been reported to exert cardioprotective effects via various mechanisms. However, whether taurine protects against Hcy-induced cardiomyocyte death by attenuating ER stress is unknown. This study aimed to evaluate the opposite effects of taurine on Hcy-induced cardiomyocyte apoptosis and their underlying mechanisms. Our results demonstrated that low-dose or short-term Hcy treatment increased the expression of glucose-regulated protein 78 (GRP78) and activated protein kinase RNA-like ER kinase (PERK), inositol-requiring enzyme 1 (IRE1), and activating transcription factor 6 (ATF6), which in turn prevented apoptotic cell death. High-dose Hcy or prolonged Hcy treatment duration significantly up-regulated levels of C/EBP homologous protein (CHOP), cleaved caspase-12, p-c-Jun N-terminal kinase (JNK), and then triggered apoptotic events. High-dose Hcy also resulted in a decrease in mitochondrial membrane potential (Δψm) and an increase in cytoplasmic cytochrome C and the expression of cleaved caspase-9. Pretreatment of cardiomyocytes with sodium 4-phenylbutyric acid (an ER stress inhibitor) significantly inhibited Hcy-induced apoptosis. Furthermore, blocking the PERK pathway partly alleviated Hcy-induced ER stress-modulated cardiomyocyte apoptosis, and down-regulated the levels of Bax and cleaved caspase-3. Experimental taurine pretreatment inhibited the expression of ER stress-related proteins, and protected against apoptotic events triggered by Hcy-induced ER stress. Taken together, our results suggest that Hcy triggered ER stress in cardiomyocytes, which was the crucial molecular mechanism mediating Hcy-induced cardiomyocyte apoptosis, and the adverse effect of Hcy could be prevented by taurine.

Proteomic Analysis of Calcium Effects on Soybean Root Tip under Flooding and Drought Stresses.

PubMed

Wang, Xin; Komatsu, Setsuko

2017-08-01

Flooding and drought are disadvantageous environmental conditions that induce cytosolic calcium in soybean. To explore the effects of flooding- and drought-induced increases in calcium, a gel-free/label-free proteomic analysis was performed. Cytosolic calcium was decreased by blocking calcium channels in the endoplasmic reticulum (ER) and plasma membrane under both stresses. Calnexin, protein disulfide isomerase, heat shock proteins and thioredoxin were predominantly affected as the ER proteins in response to calcium, and ER-associated degradation-related proteins of HCP-like superfamily protein were up-regulated under stress exposure and then down-regulated. Glycolysis, fermentation, the tricarboxylic acid cycle and amino acid metabolism were mainly induced as the types of cellular metabolism in response to calcium under both stresses. Pyruvate decarboxylase was increased and decreased under flooding and drought, respectively, and was further decreased by the reduction of cytosolic calcium; however, it was recovered by exogenous calcium under both stresses. Furthermore, pyruvate decarboxylase activity was increased under flooding, but decreased under drought. These results suggest that calcium is involved in protein folding in the ER, and ER-associated degradation might alleviate ER stress during the early stage of both stresses. Furthermore, calcium appears to modify energy metabolism, and pyruvate decarboxylase may be a key enzyme in this process under flooding and drought. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Up-regulation of K{sub ir}2.1 by ER stress facilitates cell death of brain capillary endothelial cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kito, Hiroaki; Yamazaki, Daiju; Department of Biological Chemistry, Kyoto University, Graduate School of Pharmaceutical Sciences, Kyoto

Highlights: {yields} We found that application of endoplasmic reticulum (ER) stress with tunicamycin to brain capillary endothelial cells (BCECs) induced cell death. {yields} The ER stress facilitated the expression of inward rectifier K{sup +} channel (K{sub ir}2.1) and induced sustained membrane hyperpolarization. {yields} The membrane hyperpolarization induced sustained Ca{sup 2+} entry through voltage-independent nonspecific cation channels and consequently facilitated cell death. {yields} The K{sub ir}2.1 up-regulation by ER stress is, at least in part, responsible for cell death of BCECs under pathological conditions. -- Abstract: Brain capillary endothelial cells (BCECs) form blood brain barrier (BBB) to maintain brain homeostasis. Cellmore » turnover of BCECs by the balance of cell proliferation and cell death is critical for maintaining the integrity of BBB. Here we found that stimuli with tunicamycin, endoplasmic reticulum (ER) stress inducer, up-regulated inward rectifier K{sup +} channel (K{sub ir}2.1) and facilitated cell death in t-BBEC117, a cell line derived from bovine BCECs. The activation of K{sub ir} channels contributed to the establishment of deeply negative resting membrane potential in t-BBEC117. The deep resting membrane potential increased the resting intracellular Ca{sup 2+} concentration due to Ca{sup 2+} influx through non-selective cation channels and thereby partly but significantly regulated cell death in t-BBEC117. The present results suggest that the up-regulation of K{sub ir}2.1 is, at least in part, responsible for cell death/cell turnover of BCECs induced by a variety of cellular stresses, particularly ER stress, under pathological conditions.« less

Ubiquitin Fold Modifier 1 (UFM1) and Its Target UFBP1 Protect Pancreatic Beta Cells from ER Stress-Induced Apoptosis

PubMed Central

Granvik, Mikaela; Igoillo-Esteve, Mariana; Hohmeier, Hans E.; Hendrickx, Nico; Newgard, Christopher B.; Waelkens, Etienne; Cnop, Miriam; Schuit, Frans

2011-01-01

UFM1 is a member of the ubiquitin like protein family. While the enzymatic cascade of UFM1 conjugation has been elucidated in recent years, the biological function remains largely unknown. In this report we demonstrate that the recently identified C20orf116 [1], which we name UFM1-binding protein 1 containing a PCI domain (UFBP1), andCDK5RAP3 interact with UFM1. Components of the UFM1 conjugation pathway (UFM1, UFBP1, UFL1 and CDK5RAP3) are highly expressed in pancreatic islets of Langerhans and some other secretory tissues. Co-localization of UFM1 with UFBP1 in the endoplasmic reticulum (ER)depends on UFBP1. We demonstrate that ER stress, which is common in secretory cells, induces expression of Ufm1, Ufbp1 and Ufl1 in the beta-cell line INS-1E.siRNA-mediated Ufm1 or Ufbp1knockdown enhances apoptosis upon ER stress.Silencing the E3 enzyme UFL1, results in similar outcomes, suggesting that UFM1-UFBP1 conjugation is required to prevent ER stress-induced apoptosis. Together, our data suggest that UFM1-UFBP1participate in preventing ER stress-induced apoptosis in protein secretory cells. PMID:21494687

Strong, sudden cooling alleviates the inflammatory responses in heat-stressed dairy cows based on iTRAQ proteomic analysis

NASA Astrophysics Data System (ADS)

Cheng, Jianbo; Min, Li; Zheng, Nan; Fan, Caiyun; Zhao, Shengguo; Zhang, Yangdong; Wang, Jiaqi

2018-02-01

This study was designed to investigate the effects of sudden cooling on the physiological responses of 12 heat-stressed Holstein dairy cows using an isobaric tags for relative and absolute quantification (iTRAQ) labeling approach. Plasma samples were collected from these cows during heat stress (HS), and after strong, sudden cooling in the summer (16 days later). We compared plasma proteomic data before and after sudden cooling to identify the differentially abundant proteins. The results showed that sudden cooling in summer effectively alleviated the negative consequences of HS on body temperature and production variables. Expressions of plasma hemoglobin alpha and hemoglobin beta were upregulated, whereas lipopolysaccharide-binding protein (LBP) and haptoglobin were downregulated in this process. The increase of hemoglobin after cooling may improve oxygen transport and alleviate the rise in respiration rates in heat-stressed dairy cows. The decrease of LBP and haptoglobin suggests that the inflammatory responses caused by HS are relieved after cooling. Our findings provide new insight into the physiological changes that occur when heat-stressed dairy cows experience strong, sudden cooling.

Acetylcholine ameliorates endoplasmic reticulum stress in endothelial cells after hypoxia/reoxygenation via M3 AChR-AMPK signaling.

PubMed

Bi, Xueyuan; He, Xi; Xu, Man; Zhao, Ming; Yu, Xiaojiang; Lu, Xingzhu; Zang, Weijin

2015-08-03

Endoplasmic reticulum (ER) stress is associated with various cardiovascular diseases. However, its pathophysiological relevance and the underlying mechanisms in the context of hypoxia/reoxygenation (H/R) in endothelial cells are not fully understood. Previous findings have suggested that acetylcholine (ACh), the major vagal nerve neurotransmitter, protected against cardiomyocyte injury by activating AMP-activated protein kinase (AMPK). This study investigated the role of ER stress in endothelial cells during H/R and explored the beneficial effects of ACh. Our results showed that H/R triggered ER stress and apoptosis in endothelial cells, evidenced by the elevation of glucose-regulated protein 78, cleaved caspase-12 and C/EBP homologous protein expression. ACh significantly decreased ER stress and terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling positive cells and restored ER ultrastructural changes induced by H/R, possibly via protein kinase-like ER kinase and inositol-requiring kinase 1 pathways. Additionally, 4-diphenylacetoxy-N-methylpiperidine methiodide, a type-3 muscarinic ACh receptor (M3 AChR) inhibitor, abolished ACh-mediated increase in AMPK phosphorylation during H/R. Furthermore, M3 AChR or AMPK siRNA abrogated the ACh-elicited the attenuation of ER stress in endothelial cells, indicating that the salutary effects of ACh were likely mediated by M3 AChR-AMPK signaling. Overall, ACh activated AMPK through M3 AChR, thereby inhibited H/R-induced ER stress and apoptosis in endothelial cells. We have suggested for the first time that AMPK may function as an essential intermediate step between M3 AChR stimulation and inhibition of ER stress-associated apoptotic pathway during H/R, which may help to develop novel therapeutic approaches targeting ER stress to prevent or alleviate ischemia/reperfusion injury.

ER stress-mediated cell damage contributes to the release of EDA+ fibronectin from hepatocytes in nonalcoholic fatty liver disease.

PubMed

He, Lei; Yuan, Fa-Hu; Chen, Ting; Huang, Qiang; Wang, Yu; Liu, Zhi-Guo

2017-04-01

Fibronectin containing extra domain A (EDA + FN), a functional glycoprotein participating in several cellular processes, correlates with chronic liver disease. Herein, we aim to investigate the expression and secretion of EDA + FN from hepatocytes in nonalcoholic fatty liver disease (NAFLD) and the underlying mechanisms. Circulating levels of EDA + FN were determined by ELISA in clinical samples. Western blotting and flow cytometry were performed on L02 and HepG2 cell lines to analyze whether the levels of EDA + FN were associated with endoplasmic reticulum (ER) stress-related cell death. Circulating levels of EDA + FN in NAFLD patients were significantly higher than those in control subjects, and positively related with severity of ultrasonographic steatosis score. In cultured hepatocytes, palmitate up-regulated the expression of EDA + FN in a dose-dependent manner. Conversely, when the cells were pretreated with 4-phenylbutyrate, a specific inhibitor of ER stress, up-regulation of EDA + FN could be abrogated. Moreover, silencing CHOP by shRNA enhanced the release of EDA + FN from hepatocytes following palmitate treatment, which was involved in ER stress-related cell damage. These findings suggest that the up-regulated level of EDA + FN is associated with liver damage in NAFLD, and ER stress-mediated cell damage contributes to the release of EDA + FN from hepatocytes.

Baicalin Protects the Cardiomyocytes from ER Stress-Induced Apoptosis: Inhibition of CHOP through Induction of Endothelial Nitric Oxide Synthase

PubMed Central

Wang, Bo; Guo, Xiaowang; Zeng, Chao; Xu, Yong; Shen, Liangliang; Cheng, Ke; Xia, Yuesheng; Li, Xiumin; Wang, Haichang; Fan, Li; Wang, Xiaoming

2014-01-01

Baicalin, the main active ingredient of the Scutellaria root, exerts anti-oxidant and anti-apoptotic effects in cardiovascular diseases. However, the therapeutic mechanism of baicalin remains unknown. Cultured neonatal rat cardiomyocytes were pre-treated with baicalin (0–50 µM) for 24 h, and subsequently treated with tunicamycin (100 ng/ml). Cell viability was detected by MTT assay, and cell damage was determined by LDH release and TUNEL assay. The expression of CHOP, JNK, caspase-3, eNOS was analyzed by western blot. NO was measured by DAF-FM staining. As a result, treatment with baicalin significantly reduced apoptosis induced by ER stress inducer tunicamycin in cardiomyocytes. Molecularly, baicalin ameliorated tunicamycin-induced ER stress by downregulation of CHOP. In addition, baicalin inverted tunicamycin-induced decreases of eNOS mRNA and protein levels, phospho eNOS and NO production through CHOP pathway. However, the protective effects of baicalin were significantly decreased in cardiomyocytes treated with L-NAME, which suppressed activation of nitric oxide synthase. In conclusion, our results implicate that baicalin could protect cardiomyocytes from ER stress-induced apoptosis via CHOP/eNOS/NO pathway, and suggest the therapeutic values of baicalin against ER stress-associated cardiomyocyte apoptosis. PMID:24520378

Simulation of thermal stress in Er2O3 and Al2O3 tritium penetration barriers by finite-element analysis

NASA Astrophysics Data System (ADS)

Ze, LIU; Guogang, YU; Anping, HE; Ling, WANG

2017-09-01

The physical vapor deposition method is an effective way to deposit Al2O3 and Er2O3 on 316L stainless steel substrates acting as tritium permeation barriers in a fusion reactor. The distribution of residual thermal stress is calculated both in Al2O3 and Er2O3 coating systems with planar and rough substrates using finite element analysis. The parameters influencing the thermal stress in the sputter process are analyzed, such as coating and substrate properties, temperature and Young’s modulus. This work shows that the thermal stress in Al2O3 and Er2O3 coating systems exhibit a linear relationship with substrate thickness, temperature and Young’s modulus. However, this relationship is inversed with coating thickness. In addition, the rough substrate surface can increase the thermal stress in the process of coating deposition. The adhesive strength between the coating and the substrate is evaluated by the shear stress. Due to the higher compressive shear stress, the Al2O3 coating has a better adhesive strength with a 316L stainless steel substrate than the Er2O3 coating. Furthermore, the analysis shows that it is a useful way to improve adhesive strength with increasing interface roughness.

Protectin DX suppresses hepatic gluconeogenesis through AMPK-HO-1-mediated inhibition of ER stress.

PubMed

Jung, Tae Woo; Kim, Hyung-Chun; Abd El-Aty, A M; Jeong, Ji Hoon

2017-06-01

Several studies have shown that protectins, which are ω-3 fatty acid-derived proresolution mediators, may improve insulin resistance. Recently, protectin DX (PDX) was documented to attenuate insulin resistance by stimulating IL-6 expression in skeletal muscle, thereby regulating hepatic gluconeogenesis. These findings made us investigate the direct effects of PDX on hepatic glucose metabolism in the context of diabetes. In the current study, we show that PDX regulates hepatic gluconeogenesis in a manner distinct from its indirect glucoregulatory activity via IL-6. We found that PDX stimulated AMP-activated protein kinase (AMPK) phosphorylation, thereby inducing heme oxygenase 1 (HO-1) expression. This induction blocked hepatic gluconeogenesis by suppressing endoplasmic reticulum (ER) stress in hepatocytes under hyperlipidemic conditions. These effects were significantly dampened by silencing AMPK or HO-1 expression with small interfering RNA (siRNA). We also demonstrated that administration of PDX to high fat diet (HFD)-fed mice resulted in increased hepatic AMPK phosphorylation and HO-1 expression, whereas hepatic ER stress was substantially attenuated. Furthermore, PDX treatment suppressed the expression of gluconeogenic genes, thereby decreasing blood glucose levels in HFD-fed mice. In conclusion, our findings suggest that PDX inhibits hepatic gluconeogenesis via AMPK-HO-1-dependent suppression of ER stress. Thus, PDX may be an effective therapeutic target for the treatment of insulin resistance and type 2 diabetes through the regulation of hepatic gluconeogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

Hydrogen alleviates hyperoxic acute lung injury related endoplasmic reticulum stress in rats through upregulation of SIRT1.

PubMed

Sun, Qiang; Han, Wenjie; Hu, Huijun; Fan, Danfeng; Li, Yanbo; Zhang, Yu; Lv, Yan; Li, Mingxin; Pan, Shuyi

2017-06-01

Hyperoxic acute lung injury (HALI) is a major clinical problem for patients undergoing supplemental oxygen therapy. Currently in clinical settings there exist no effective means of prevention or treatment methods. Our previous study found that: hydrogen could reduce HALI, as well as oxidative stress. This research will further explore the mechanism underlying the protective effect of hydrogen on oxygen toxicity. Rats were randomly assigned into three experimental groups and were exposed in a oxygen chamber for 60 continuous hours: 100% balanced air (control); 100% oxygen (HALI); 100% oxygen with hydrogen treatment (HALI + HRS). We examined lung function by wet to dry ratio of lung, lung pleural effusion and cell apoptosis. We also detected endoplasmic reticulum stress (ERS) by examining the expression of CHOP, GRP78 and XBP1. We further investigated the role of Sirtuin 1 (SIRT1) in HALI, which contributes to cellular regulation including ERS, by examining its expression after hydrogen treatment with SIRT1 inhibitor. Hydrogen could significantly reduce HALI by reducing lung edema and apoptosis, inhibiting the elevating of ERS and increased SIRT1 expression. By inhibition of SIRT1 expression, the effect of hydrogen on prevention of HALI is significantly weakened, the inhibition of the ERS was also reversed. Our findings indicate that hydrogen could reduce HALI related ERS and the mechanism of hydrogen may be associated with upregulation of SIRT1, this study reveals the molecular mechanisms underlying the protective effect of hydrogen, which provides a new theoretical basis for clinical application of hydrogen.

An exploration of factors associated with post-traumatic stress in ER nurses.

PubMed

Lavoie, Stéphane; Talbot, Lise R; Mathieu, Luc; Dallaire, Clémence; Dubois, Marie-France; Courcy, François

2016-03-01

Emergency room (ER) nurses are frequently exposed to traumatic events (TE) at work. These events can lead to symptoms of post-traumatic stress disorder (PTSD). The goal of the present study was to describe the factors associated with PTSD symptoms. A cross-sectional descriptive correlational design was used. The sample consisted of 35 nurses from an ER in Québec (Canada). Data were collected through self-administered questionnaires. TEs presenting a grief component (e.g. intentional injury to a child and patient suicide) are positively associated with peritraumatic distress (PD) in the days after the event. PD is positively associated with PTSD symptoms. Two personality traits (neuroticism and extraversion) should also be considered. Neuroticism is positively associated with PD whereas extraversion is negatively associated with PD and PTSD symptoms. The results are consistent with the literature, but some of these results are new to nurses. They suggest that in this population, TEs in the ER represent 'red flags'. Their occurrence should mobilise support structures. PD and its personality traits are also key factors to consider. To provide adequate support for nurses, ER managers should be on the alert for these conditions. Interventions should be adapted to these findings. © 2015 John Wiley & Sons Ltd.

Baicalin Ameliorates H2O2 Induced Cytotoxicity in HK-2 Cells through the Inhibition of ER Stress and the Activation of Nrf2 Signaling

PubMed Central

Lin, Miao; Li, Long; Zhang, Yi; Zheng, Long; Xu, Ming; Rong, Ruiming; Zhu, Tongyu

2014-01-01

Renal ischemia-reperfusion injury plays a key role in renal transplantation and greatly affects the outcome of allograft. Our previous study proved that Baicalin, a flavonoid glycoside isolated from Scutellaria baicalensis, protects kidney from ischemia-reperfusion injury. This study aimed to study the underlying mechanism in vitro. Human renal proximal tubular epithelial cell line HK-2 cells were stimulated by H2O2 with and without Baicalin pretreatment. The cell viability, apoptosis and oxidative stress level were measured. The expression of endoplasmic reticulum (ER) stress hallmarks, such as binding immunoglobulin protein (BiP) and C/EBP homologous protein (CHOP), were analyzed by western blot and real-time PCR. NF-E2-related factor 2 (Nrf2) expression was also measured. In the H2O2 group, cell viability decreased and cell apoptosis increased. Reactive Oxygen Species (ROS) and Glutathione/Oxidized Glutathione (GSH/GSSG) analysis revealed increased oxidative stress. ER stress and Nrf2 signaling also increased. Baicalin pretreatment ameliorated H2O2-induced cytotoxicity, reduced oxidative stress and ER stress and further activated the anti-oxidative Nrf2 signaling pathway. The inducer of ER stress and the inhibitor of Nrf2 abrogated the protective effects, while the inhibitor of ER stress and the inducer of Nrf2 did not improve the outcome. This study revealed that Baicalin pretreatment serves a protective role against H2O2-induced cytotoxicity in HK-2 cells, where the inhibition of ER stress and the activation of downstream Nrf2 signaling are involved. PMID:25029541

Feedback regulation on PTEN/AKT pathway by the ER stress kinase PERK mediated by interaction with the Vault complex.

PubMed

Zhang, Wei; Neo, Suat Peng; Gunaratne, Jayantha; Poulsen, Anders; Boping, Liu; Ong, Esther Hongqian; Sangthongpitag, Kanda; Pendharkar, Vishal; Hill, Jeffrey; Cohen, Stephen M

2015-03-01

The high proliferation rate of cancer cells, together with environmental factors such as hypoxia and nutrient deprivation can cause Endoplasmic Reticulum (ER) stress. The protein kinase PERK is an essential mediator in one of the three ER stress response pathways. Genetic and pharmacological inhibition of PERK has been reported to limit tumor growth in xenograft models. Here we provide evidence that inactive PERK interacts with the nuclear pore-associated Vault complex protein and that this compromises Vault-mediated nuclear transport of PTEN. Pharmacological inhibition of PERK under ER stress results is abnormal sequestration of the Vault complex, leading to increased cytoplasmic PTEN activity and lower AKT activation. As the PI3K/PTEN/AKT pathway is crucial for many aspects of cell growth and survival, this unexpected effect of PERK inhibitors on AKT activity may have implications for their potential use as therapeutic agents. Copyright © 2014. Published by Elsevier Inc.

Induction of ER Stress-Mediated Apoptosis by α-Lipoic Acid in A549 Cell Lines

PubMed Central

Kim, Jong In; Lee, Chang Min; Park, Eok-Sung; Kim, Ki Nyun; Kim, Hyung Chul; Lee, Hae Young

2012-01-01

Background α-Lipoic acid (α-LA) has been studied as an anticancer agent as well as a therapeutic agent for diabetes and obesity. We performed this study to evaluate the anticancer effects and mechanisms of α-LA in a lung cancer cell line, A549. Materials and Methods α-LA-induced apoptosis of A549 cells was detected by fluorescence-activated cell sorting analysis and a DNA fragmentation assay. Expression of apoptosis-related genes was analyzed by western blot and reverse transcription-polymerase chain reaction analyses. Results α-LA induced apoptosis and DNA fragmentation in A549 cells in a dose- and time-dependent manner. α-LA increased caspase activity and the degradation of poly (ADP-ribose) polymerase. It induced expression of endoplasmic reticulum (ER) stress-related genes, such as glucose-regulated protein 78, C/EBP-homologous protein, and the short form of X-box binding protein-1, and decreased expression of the anti-apoptotic protein, X-linked inhibitor of apoptosis protein. Reactive oxygen species (ROS) production was induced by α-LA, and the antioxidant N-acetyl-L-cysteine decreased the α-LA-induced increase in expression of apoptosis and ER stress-related proteins. Conclusion α-LA induced ER stress-mediated apoptosis in A549 cells via ROS. α-LA may therefore be clinically useful for treating lung cancer. PMID:22363901

Quercetin prevents chronic unpredictable stress induced behavioral dysfunction in mice by alleviating hippocampal oxidative and inflammatory stress.

PubMed

Mehta, Vineet; Parashar, Arun; Udayabanu, Malairaman

2017-03-15

It is now evident that chronic stress is associated with anxiety, depression and cognitive dysfunction and very few studies have focused on identifying possible methods to prevent these stress-induced disorders. Previously, we identified abundance of quercetin in Urtica dioica extract, which efficiently attenuated stress related complications. Therefore, current study was designed to investigate the effect of quercetin on chronic unpredicted stress (CUS) induced behavioral dysfunction, oxidative stress and neuroinflammation in the mouse hippocampus. Animals were subjected to unpredicted stress for 21days, during which 30mg/kg quercetin was orally administered to them. Effect of CUS and quercetin treatment on animal behavior was assessed between day 22-26. Afterward, the hippocampus was processed to evaluate neuronal damage, oxidative and inflammatory stress. Results revealed that stressed animals were highly anxious (Elevated Plus Maze and Open Field), showed depressive-like behavior (sucrose preference task), performed poorly in short-term and long-term associative memory task (passive avoidance step-through task) and displayed reduced locomotion (open field). Quercetin alleviated behavioral dysfunction in chronically stressed animals. Compared to CUS, quercetin treatment significantly reduced anxiety, attenuated depression, improved cognitive dysfunction and normalized locomotor activity. Further, CUS elevated the levels of oxidative stress markers (TBARS, nitric oxide), lowered antioxidants (total thiol, catalase), enhanced expression of pro-inflammatory cytokines (IL-6, TNF-α, IL-1β and COX-2) in the hippocampus and damaged hippocampal neurons. Quercetin treatment significantly lowered oxidative and inflammatory stress and prevented neural damage. In conclusion, quercetin can efficiently prevent stress induced neurological complications by rescuing brain from oxidative and inflammatory stress. Copyright © 2017 Elsevier Inc. All rights reserved.

Deep-brain magnetic stimulation promotes adult hippocampal neurogenesis and alleviates stress-related behaviors in mouse models for neuropsychiatric disorders

PubMed Central

2014-01-01

Background Repetitive Transcranial Magnetic Stimulation (rTMS)/ Deep-brain Magnetic Stimulation (DMS) is an effective therapy for various neuropsychiatric disorders including major depression disorder. The molecular and cellular mechanisms underlying the impacts of rTMS/DMS on the brain are not yet fully understood. Results Here we studied the effects of deep-brain magnetic stimulation to brain on the molecular and cellular level. We examined the adult hippocampal neurogenesis and hippocampal synaptic plasticity of rodent under stress conditions with deep-brain magnetic stimulation treatment. We found that DMS promotes adult hippocampal neurogenesis significantly and facilitates the development of adult new-born neurons. Remarkably, DMS exerts anti-depression effects in the learned helplessness mouse model and rescues hippocampal long-term plasticity impaired by restraint stress in rats. Moreover, DMS alleviates the stress response in a mouse model for Rett syndrome and prolongs the life span of these animals dramatically. Conclusions Deep-brain magnetic stimulation greatly facilitates adult hippocampal neurogenesis and maturation, also alleviates depression and stress-related responses in animal models. PMID:24512669

Sigma-1 Receptor Chaperone at the ER-Mitochondrion Interface Mediates the Mitochondrion-ER-Nucleus Signaling for Cellular Survival

PubMed Central

Mori, Tomohisa; Hayashi, Teruo; Hayashi, Eri; Su, Tsung-Ping

2013-01-01

The membrane of the endoplasmic reticulum (ER) of a cell forms contacts directly with mitochondria whereby the contact is referred to as the mitochondrion-associated ER membrane or the MAM. Here we found that the MAM regulates cellular survival via an MAM-residing ER chaperone the sigma-1 receptor (Sig-1R) in that the Sig-1R chaperones the ER stress sensor IRE1 to facilitate inter-organelle signaling for survival. IRE1 is found in this study to be enriched at the MAM in CHO cells. We found that IRE1 is stabilized at the MAM by Sig-1Rs when cells are under ER stress. Sig-1Rs stabilize IRE1 and thus allow for conformationally correct IRE1 to dimerize into the long-lasting, activated endonuclease. The IRE1 at the MAM also responds to reactive oxygen species derived from mitochondria. Therefore, the ER-mitochondrion interface serves as an important subcellular entity in the regulation of cellular survival by enhancing the stress-responding signaling between mitochondria, ER, and nucleus. PMID:24204710

Sigma-1 receptor chaperone at the ER-mitochondrion interface mediates the mitochondrion-ER-nucleus signaling for cellular survival.

PubMed

Mori, Tomohisa; Hayashi, Teruo; Hayashi, Eri; Su, Tsung-Ping

2013-01-01

The membrane of the endoplasmic reticulum (ER) of a cell forms contacts directly with mitochondria whereby the contact is referred to as the mitochondrion-associated ER membrane or the MAM. Here we found that the MAM regulates cellular survival via an MAM-residing ER chaperone the sigma-1 receptor (Sig-1R) in that the Sig-1R chaperones the ER stress sensor IRE1 to facilitate inter-organelle signaling for survival. IRE1 is found in this study to be enriched at the MAM in CHO cells. We found that IRE1 is stabilized at the MAM by Sig-1Rs when cells are under ER stress. Sig-1Rs stabilize IRE1 and thus allow for conformationally correct IRE1 to dimerize into the long-lasting, activated endonuclease. The IRE1 at the MAM also responds to reactive oxygen species derived from mitochondria. Therefore, the ER-mitochondrion interface serves as an important subcellular entity in the regulation of cellular survival by enhancing the stress-responding signaling between mitochondria, ER, and nucleus.

Cellular stress and apoptosis contribute to the pathogenesis of autism spectrum disorder.

PubMed

Dong, Daoyin; Zielke, Horst Ronald; Yeh, David; Yang, Peixin

2018-05-15

Development's Brain Tissue Bank for the analysis of cellular and molecular changes in autistic brains. Three key brain regions, the hippocampus, the cerebellum, and the frontal cortex, in six cases of autistic brains and six cases of non-autistic brains from 6 to 16 years old deceased children, were analyzed. The current study investigated the possible roles of endoplasmic reticulum (ER) stress, oxidative stress, and apoptosis as molecular mechanisms underlying autism. The activation of three signals of ER stress (protein kinase R-like endoplasmic reticulum kinase, activating transcription factor 6, inositol-requiring enzyme 1 alpha) varies in different regions. The occurrence of ER stress leads to apoptosis in autistic brains. ER stress may result from oxidative stress because of elevated levels of the oxidative stress markers: 4-Hydroxynonenal and nitrotyrosine-modified proteins in autistic brains. These findings suggest that cellular stress and apoptosis may contribute to the autistic phenotype. Pharmaceuticals and/or dietary supplements, which can alleviate ER stress, oxidative stress and apoptosis, may be effective in ameliorating adverse phenotypes associated with autism. © 2018 International Society for Autism Research, Wiley Periodicals, Inc.

Intrinsic attenuation of post-irradiation calcium and ER stress imparts significant radioprotection to lepidopteran insect cells.

PubMed

Guleria, Ayushi; Thukral, Neha; Chandna, Sudhir

2018-04-15

Sf9 lepidopteran insect cells are 100-200 times more radioresistant than mammalian cells. This distinctive feature thus makes them suitable for studies exploring radioprotective molecular mechanisms. It has been established from previous studies of our group that downstream mitochondrial apoptotic signaling pathways in Sf9 cells are quite similar to mammalian cells, implicating the upstream signaling pathways in their extensive radioresistance. In the present study, intracellular and mitochondrial calcium levels remained unaltered in Sf9 cells in response to radiation, in sharp contrast to human (HEK293T) cells. The isolated mitochondria from Sf9 cells exhibited nearly 1.5 times greater calcium retention capacity than mammalian cells, highlighting their inherent stress resilience. Importantly, UPR/ER stress marker proteins (p-eIF2α, GRP4 and SERCA) remained unaltered by radiation and suggested highly attenuated ER and calcium stress. Lack of SERCA induction further corroborates the lack of radiation-induced calcium mobilization in these cells. The expression of CaMKII, an important effector molecule of calcium signaling, did not alter in response to radiation. Inhibiting CaMKII by KN-93 or suppressing CaM by siRNA failed to alter Sf9 cells response to radiation and suggests CaM-CaMKII independent radiation signaling. Therefore, this study suggests that attenuated calcium signaling/ER stress is an important determinant of lepidopteran cell radioresistance. Copyright © 2018 Elsevier Inc. All rights reserved.

The ER stress sensor PERK luminal domain functions as a molecular chaperone to interact with misfolded proteins.

PubMed

Wang, Peng; Li, Jingzhi; Sha, Bingdong

2016-12-01

PERK is one of the major sensor proteins which can detect the protein-folding imbalance generated by endoplasmic reticulum (ER) stress. It remains unclear how the sensor protein PERK is activated by ER stress. It has been demonstrated that the PERK luminal domain can recognize and selectively interact with misfolded proteins but not native proteins. Moreover, the PERK luminal domain may function as a molecular chaperone to directly bind to and suppress the aggregation of a number of misfolded model proteins. The data strongly support the hypothesis that the PERK luminal domain can interact directly with misfolded proteins to induce ER stress signaling. To illustrate the mechanism by which the PERK luminal domain interacts with misfolded proteins, the crystal structure of the human PERK luminal domain was determined to 3.2 Å resolution. Two dimers of the PERK luminal domain constitute a tetramer in the asymmetric unit. Superimposition of the PERK luminal domain molecules indicated that the β-sandwich domain could adopt multiple conformations. It is hypothesized that the PERK luminal domain may utilize its flexible β-sandwich domain to recognize and interact with a broad range of misfolded proteins.

The Effect of Boric Acid and Borax on Oxidative Stress, Inflammation, ER Stress and Apoptosis in Cisplatin Toxication and Nephrotoxicity Developing as a Result of Toxication.

PubMed

Hazman, Ömer; Bozkurt, Mehmet Fatih; Fidan, Abdurrahman Fatih; Uysal, Fadime Erkan; Çelik, Sefa

2018-06-01

The development of treatment protocols that can reduce side effects in chemotherapy applications is extremely important in terms of cancer treatment. In this context, it was aimed to investigate the effects of boric acid and borax on cisplatin toxicity (nephrotoxicity) in rats. In the experimental phase, eight groups were formed from rats. Boric acid and borax were given to the treatment groups with three different doses using gavage. On the fifth day of the study, cisplatin (10 mg/kg) was administered to all rats except the control group. At the end of the study, oxidative stress-related (GSH, MDA, PCO, GPx, 8-OHdG), inflammation-related (TNF-α, IL-1β, IL-18, MCP-1, ICAM, TGF-β), apoptosis-related (p53, caspase 1, 3, 8, 12, bcl-2, bcl-xL, NFkB), and ER stress-related (GRP78, ATF-6, PERK) basic parameters were analyzed in serum, erythrocyte, and kidney tissues. Kidney tissues were also examined by histopathological and immunohistochemical methods. Borax and boric acid at different doses decreased inflammation and oxidative stress caused by cisplatin toxicity and increased ER stress. As a result of the treatments applied to experimental animals, it was determined that boric acid and borax reduced apoptotic damage in kidney tissue, but the decrease was statistically significant only in 200 mg/kg boric acid-administered group. In the study, low anti-apoptotic effects of borate doses with the anti-inflammatory and antioxidant effect may be due to increased ER stress at the relevant doses. Further studies on the effects of boron compounds on ER stress and apoptotic mechanisms may clarify this issue. Thus, possible side effects or if there are new usage areas of borone compounds which have many usage areas in clinics can be detected.

The Effect of Glucose Concentration and Sodium Phenylbutyrate Treatment on Mitochondrial Bioenergetics and ER Stress in 3T3-L1 Adipocytes

PubMed Central

Tanis, Ross M.; Piroli, Gerardo G.; Day, Stani D.; Frizzell, Norma

2016-01-01

While the 3T3-L1 adipocyte model is routinely used for the study of obesity and diabetes, the mitochondrial respiratory profile in normal versus high glucose has not been examined in detail. We matured adipocytes in normal (5 mM) or high (30 mM) glucose and insulin and examined the mitochondrial bioenergetics. We also assessed the requirement for the Unfolded Protein Response (UPR) and ER stress under these conditions. Basal respiration was ∼1.7-fold greater in adipocytes that had matured in 30 mM glucose; however, their ability to increase oxygen consumption in response to stress was impaired. Adipogenesis proceeded in both normal and high glucose with concomitant activation of the UPR, but only high glucose was associated with increased levels of ER stress and mitochondrial stress as observed by parallel increases in CHOP and protein succination. Treatment of adipocytes with sodium phenylbutyrate relieved mitochondrial stress through a reduction in mitochondrial respiration. Our data suggests that mitochondrial stress, protein succination and ER stress are uniquely linked in adipocytes matured in high glucose. PMID:25448036

Carbon monoxide alleviates lipopolysaccharide-induced oxidative stress injury through suppressing the expression of Fis1 in NR8383 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Jia; Yu, Jian-bo, E-mail: yujianbo11@126.com; Liu, Wei

Acute respiratory distress syndrome (ARDS) is one of the most devastating complications of sepsis lacking of effective therapy. Mitochondrial dynamics undergoing continuous fusion and fission play a crucial role in mitochondrial structure and function. Fis1, as a small protein located on the outer membrane of mitochondria, has been thought to be an important protein mediated mitochondrial fission. During ARDS, alveolar macrophages suffer from increased oxidative stress and apoptosis, and also accompanied by disrupted mitochondrial dynamics. In addition, as one of the products of heme degradation catalyzed by heme oxygenase, carbon monoxide (CO) possesses powerful protective properties in vivo or inmore » vitro models, such as anti-inflammatory, antioxidant and anti-apoptosis function. However, there is little evidence that CO alleviates oxidative stress damage through altering mitochondrial fission in alveolar macrophages. In the present study, our results showed that CO increased cell vitality, improved mitochondrial SOD activity, reduced reactive oxygen species (ROS) production and inhibited cell apoptosis in NR8383 exposed to LPS. Meanwhile, CO decreased the expression of Fis1, increased mitochondrial membrane potential and sustained elongation of mitochondria in LPS-incubated NR8383. Overall, our study underscored a critical role of CO in suppressing the expression of Fis1 and alleviating LPS- induced oxidative stress damage in alveolar macrophages. - Highlights: • LPS exposure triggered cell injury in NR8383. • CO alleviated LPS-induced oxidative stress damage in alveolar macrophages. • CO inhibited Fis1 levels and improved mitochondrial function in LPS-induced NR8383.« less

Biochar soil amendment on alleviation of drought and salt stress in plants: a critical review.

PubMed

Ali, Shafaqat; Rizwan, Muhammad; Qayyum, Muhammad Farooq; Ok, Yong Sik; Ibrahim, Muhammad; Riaz, Muhammad; Arif, Muhammad Saleem; Hafeez, Farhan; Al-Wabel, Mohammad I; Shahzad, Ahmad Naeem

2017-05-01

Drought and salt stress negatively affect soil fertility and plant growth. Application of biochar, carbon-rich material developed from combustion of biomass under no or limited oxygen supply, ameliorates the negative effects of drought and salt stress on plants. The biochar application increased the plant growth, biomass, and yield under either drought and/or salt stress and also increased photosynthesis, nutrient uptake, and modified gas exchange characteristics in drought and salt-stressed plants. Under drought stress, biochar increased the water holding capacity of soil and improved the physical and biological properties of soils. Under salt stress, biochar decreased Na + uptake, while increased K + uptake by plants. Biochar-mediated increase in salt tolerance of plants is primarily associated with improvement in soil properties, thus increasing plant water status, reduction of Na + uptake, increasing uptake of minerals, and regulation of stomatal conductance and phytohormones. This review highlights both the potential of biochar in alleviating drought and salt stress in plants and future prospect of the role of biochar under drought and salt stress in plants.

Salicylic acid alleviates decreases in photosynthesis under heat stress and accelerates recovery in grapevine leaves.

PubMed

Wang, Li-Jun; Fan, Ling; Loescher, Wayne; Duan, Wei; Liu, Guo-Jie; Cheng, Jian-Shan; Luo, Hai-Bo; Li, Shao-Hua

2010-02-23

Although the effect of salicylic acid (SA) on photosynthesis of plants including grapevines has been investigated, very little is yet known about the effects of SA on carbon assimilation and several components of PSII electron transport (donor side, reaction center and acceptor side). In this study, the impact of SA pretreatment on photosynthesis was evaluated in the leaves of young grapevines before heat stress (25 degrees C), during heat stress (43 degrees C for 5 h), and through the following recovery period (25 degrees C). Photosynthetic measures included gas exchange parameters, PSII electron transport, energy dissipation, and Rubisco activation state. The levels of heat shock proteins (HSPs) in the chloroplast were also investigated. SA did not significantly (P < 0.05) influence the net photosynthesis rate (Pn) of leaves before heat stress. But, SA did alleviate declines in Pn and Rubisco activation state, and did not alter negative changes in PSII parameters (donor side, acceptor side and reaction center QA) under heat stress. Following heat treatment, the recovery of Pn in SA-treated leaves was accelerated compared with the control (H2O-treated) leaves, and, donor and acceptor parameters of PSII in SA-treated leaves recovered to normal levels more rapidly than in the controls. Rubisco, however, was not significantly (P < 0.05) influenced by SA. Before heat stress, SA did not affect level of HSP 21, but the HSP21 immune signal increased in both SA-treated and control leaves during heat stress. During the recovery period, HSP21 levels remained high through the end of the experiment in the SA-treated leaves, but decreased in controls. SA pretreatment alleviated the heat stress induced decrease in Pn mainly through maintaining higher Rubisco activation state, and it accelerated the recovery of Pn mainly through effects on PSII function. These effects of SA may be related in part to enhanced levels of HSP21.

Activation of ATP-sensitive potassium channel by iptakalim normalizes stress-induced HPA axis disorder and depressive behaviour by alleviating inflammation and oxidative stress in mouse hypothalamus.

PubMed

Zhao, Xiao-Jie; Zhao, Zhan; Yang, Dan-Dan; Cao, Lu-Lu; Zhang, Ling; Ji, Juan; Gu, Jun; Huang, Ji-Ye; Sun, Xiu-Lan

2017-04-01

Stress-induced disturbance of the hypothalamic-pituitary-adrenal (HPA) axis is strongly implicated in incidence of mood disorders. A heightened neuroinflammatory response and oxidative stress play a fundamental role in the dysfunction of the HPA axis. We have previously demonstrated that iptakalim (Ipt), a new ATP-sensitive potassium (K-ATP) channel opener, could prevent oxidative injury and neuroinflammation against multiple stimuli-induced brain injury. The present study was to demonstrate the impacts of Ipt in stress-induced HPA axis disorder and depressive behavior. We employed 2 stress paradigms: 8 weeks of continuous restraint stress (chronic restraint stress, CRS) and 2h of restraint stress (acute restraint stress, ARS), to mimic both chronic stress and severe acute stress. Prolonged (4 weeks) and short-term (a single injection) Ipt treatment was administered 30min before each stress paradigm. We found that HPA axis was altered after stress, with different responses to CRS (lower ACTH and CORT, higher AVP, but normal CRH) and ARS (higher CRH, ACTH and CORT, but normal AVP). Both prolonged and short-term Ipt treatment normalized stress-induced HPA axis disorders and abnormal behaviors in mice. CRS and ARS up-regulated mRNA levels of inflammation-related molecules (TNFα, IL-1β, IL-6 and TLR4) and oxidative stress molecules (gp91phox, iNOS and Nrf2) in the mouse hypothalamus. Double immunofluorescence showed CRS and ARS increased microglia activation (CD11b and TNFα) and oxidative stress in neurons (NeuN and gp91phox), which were alleviated by Ipt. Therefore, the present study reveals that Ipt could prevent against stress-induced HPA axis disorders and depressive behavior by alleviating inflammation and oxidative stress in the hypothalamus. Copyright © 2017 Elsevier Inc. All rights reserved.

Anti-Fibrotic Effect of Losartan, an Angiotensin II Receptor Blocker, Is Mediated through Inhibition of ER Stress via Up-Regulation of SIRT1, Followed by Induction of HO-1 and Thioredoxin

PubMed Central

Kim, Hyosang; Baek, Chung Hee; Lee, Raymond Bok; Chang, Jai Won; Yang, Won Seok; Lee, Sang Koo

2017-01-01

Endoplasmic reticulum (ER) stress is increasingly identified as modulator of fibrosis. Losartan, an angiotensin II receptor blocker, has been widely used as the first choice of treatment in chronic renal diseases. We postulated that anti-fibrotic effect of losartan is mediated through inhibition of ER stress via SIRT1 (silent mating type information regulation 2 homolog 1) hemeoxygenase-1 (HO-1)/thioredoxin pathway. Renal tubular cells, tunicamycin (TM)-induced ER stress, and unilateral ureteral obstruction (UUO) mouse model were used. Expression of ER stress was assessed by Western blot analysis and immunohistochemical stain. ER stress was induced by chemical ER stress inducer, tunicamycin, and non-chemical inducers such as TGF-β, angiotensin II, high glucose, and albumin. Losartan suppressed the TM-induced ER stress, as shown by inhibition of TM-induced expression of GRP78 (glucose related protein 78) and p-eIF2α (phosphospecific-eukaryotic translation initiation factor-2α), through up-regulation of SIRT1 via HO-1 and thioredoxin. Losartan also suppressed the ER stress by non-chemical inducers. In both animal models, losartan reduced the tubular expression of GRP78, which were abolished by pretreatment with sirtinol (SIRT1 inhibitor). Sirtinol also blocked the inhibitory effect of losartan on the UUO-induced renal fibrosis. These findings provide new insights into renoprotective effects of losartan and suggest that SIRT1, HO-1, and thioredoxin may be potential pharmacological targets in kidney diseases under excessive ER stress condition. PMID:28146117

Anti-Fibrotic Effect of Losartan, an Angiotensin II Receptor Blocker, Is Mediated through Inhibition of ER Stress via Up-Regulation of SIRT1, Followed by Induction of HO-1 and Thioredoxin.

PubMed

Kim, Hyosang; Baek, Chung Hee; Lee, Raymond Bok; Chang, Jai Won; Yang, Won Seok; Lee, Sang Koo

2017-01-31

Endoplasmic reticulum (ER) stress is increasingly identified as modulator of fibrosis. Losartan, an angiotensin II receptor blocker, has been widely used as the first choice of treatment in chronic renal diseases. We postulated that anti-fibrotic effect of losartan is mediated through inhibition of ER stress via SIRT1 (silent mating type information regulation 2 homolog 1) hemeoxygenase-1 (HO-1)/thioredoxin pathway. Renal tubular cells, tunicamycin (TM)-induced ER stress, and unilateral ureteral obstruction (UUO) mouse model were used. Expression of ER stress was assessed by Western blot analysis and immunohistochemical stain. ER stress was induced by chemical ER stress inducer, tunicamycin, and non-chemical inducers such as TGF-β, angiotensin II, high glucose, and albumin. Losartan suppressed the TM-induced ER stress, as shown by inhibition of TM-induced expression of GRP78 (glucose related protein 78) and p-eIF2α (phosphospecific-eukaryotic translation initiation factor-2α), through up-regulation of SIRT1 via HO-1 and thioredoxin. Losartan also suppressed the ER stress by non-chemical inducers. In both animal models, losartan reduced the tubular expression of GRP78, which were abolished by pretreatment with sirtinol (SIRT1 inhibitor). Sirtinol also blocked the inhibitory effect of losartan on the UUO-induced renal fibrosis. These findings provide new insights into renoprotective effects of losartan and suggest that SIRT1, HO-1, and thioredoxin may be potential pharmacological targets in kidney diseases under excessive ER stress condition.

Involvement of ER Stress in Dysmyelination of Pelizaeus-Merzbacher Disease with PLP1 Missense Mutations Shown by iPSC-Derived Oligodendrocytes

PubMed Central

Numasawa-Kuroiwa, Yuko; Okada, Yohei; Shibata, Shinsuke; Kishi, Noriyuki; Akamatsu, Wado; Shoji, Masanobu; Nakanishi, Atsushi; Oyama, Manabu; Osaka, Hitoshi; Inoue, Ken; Takahashi, Kazutoshi; Yamanaka, Shinya; Kosaki, Kenjiro; Takahashi, Takao; Okano, Hideyuki

2014-01-01

Summary Pelizaeus-Merzbacher disease (PMD) is a form of X-linked leukodystrophy caused by mutations in the proteolipid protein 1 (PLP1) gene. Although PLP1 proteins with missense mutations have been shown to accumulate in the rough endoplasmic reticulum (ER) in disease model animals and cell lines transfected with mutant PLP1 genes, the exact pathogenetic mechanism of PMD has not previously been clarified. In this study, we established induced pluripotent stem cells (iPSCs) from two PMD patients carrying missense mutation and differentiated them into oligodendrocytes in vitro. In the PMD iPSC-derived oligodendrocytes, mislocalization of mutant PLP1 proteins to the ER and an association between increased susceptibility to ER stress and increased numbers of apoptotic oligodendrocytes were observed. Moreover, electron microscopic analysis demonstrated drastically reduced myelin formation accompanied by abnormal ER morphology. Thus, this study demonstrates the involvement of ER stress in pathogenic dysmyelination in the oligodendrocytes of PMD patients with the PLP1 missense mutation. PMID:24936452

ER stress triggers MCP-1 expression through SET7/9-induced histone methylation in the kidneys of db/db mice.

PubMed

Chen, Jigang; Guo, Yanhong; Zeng, Wei; Huang, Li; Pang, Qi; Nie, Ling; Mu, Jiao; Yuan, Fahuan; Feng, Bing

2014-04-15

Epigenetics plays a key role in the pathogenesis of diabetic nephropathy (DN), although the precise regulatory mechanism is still unclear. Here, we examined the role of endoplasmic reticulum (ER) stress in histone H3 lysine 4 (H3K4) methyltransferase SET7/9-induced monocyte chemoattractant protein-1 (MCP-1) expression in the kidneys of db/db mice. Our results indicate that the expression of MCP-1 significantly increased in the kidneys of db/db mice in a time-dependent manner. An increased chromatin mark associated with an active gene (H3K4me1) at MCP-1 promoters accompanied this change in expression. The expression of SET7/9 and the recruitment to these promoters were also elevated. SET7/9 gene silencing with small interfering (si) RNAs significantly attenuated the expression of H3K4me1 and MCP-1. Furthermore, expression of signaling regulator glucose-regulated protein 78 (GRP78), a monitor of ER stress, significantly increased in the kidneys of db/db mice. The expression of spliced X-box binding protein 1 (XBP1s), an ER stress-inducible transcription factor, and recruitment to the SET7/9 promoters were also increased. XBP1s gene silencing with siRNAs significantly attenuated the expression of SET7/9, H3K4me1, and MCP-1. The chaperone betaine not only effectively downregulated the GRP78 and XBP1s expression levels but also markedly decreased the SET7/9, H3K4me1, and MCP-1 levels. Luciferase reporter assay demonstrated that XBP1s participated in ER stress-induced SET7/9 transcription, Taken together, these results reveal that ER stress can trigger the expression of MCP-1, in part through the XBP1s-mediated induction of SET7/9.

Preconditioning with Endoplasmic Reticulum Stress Ameliorates Endothelial Cell Inflammation

PubMed Central

Leonard, Antony; Paton, Adrienne W.; El-Quadi, Monaliza; Paton, James C.; Fazal, Fabeha

2014-01-01

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. PMID:25356743

Preconditioning with endoplasmic reticulum stress ameliorates endothelial cell inflammation.

PubMed

Leonard, Antony; Paton, Adrienne W; El-Quadi, Monaliza; Paton, James C; Fazal, Fabeha

2014-01-01

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.

Involvement of ethylene in gibberellic acid-induced sulfur assimilation, photosynthetic responses, and alleviation of cadmium stress in mustard.

PubMed

Masood, Asim; Khan, M Iqbal R; Fatma, Mehar; Asgher, Mohd; Per, Tasir S; Khan, Nafees A

2016-07-01

The role of gibberellic acid (GA) or sulfur (S) in stimulation of photosynthesis is known. However, information on the involvement of ethylene in GA-induced photosynthetic responses and cadmium (Cd) tolerance is lacking. This work shows that ethylene is involved in S-assimilation, photosynthetic responses and alleviation of Cd stress by GA in mustard (Brassica juncea L.). Plants grown with 200 mg Cd kg(-1) soil were less responsive to ethylene despite high ethylene evolution and showed photosynthetic inhibition. Plants receiving 10 μM GA spraying plus 100 mg S kg(-1) soil supplementation exhibited increased S-assimilation and photosynthetic responses under Cd stress. Application of GA plus S decreased oxidative stress of plants grown with Cd and limited stress ethylene formation to the range suitable for promoting sulfur use efficiency (SUE), glutathione (GSH) production and photosynthesis. The role of ethylene in GA-induced S-assimilation and reversal of photosynthetic inhibition by Cd was substantiated by inhibiting ethylene biosynthesis with the use of aminoethoxyvinylglycine (AVG). The suppression of S-assimilation and photosynthetic responses by inhibiting ethylene in GA plus S treated plants under Cd stress indicated the involvement of ethylene in GA-induced S-assimilation and Cd stress alleviation. The outcome of the study is important to unravel the interaction between GA and ethylene and their role in Cd tolerance in plants. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Detrimental effects of proteasome inhibition activity in Drosophila melanogaster: implication of ER stress, autophagy, and apoptosis.

PubMed

Velentzas, Panagiotis D; Velentzas, Athanassios D; Mpakou, Vassiliki E; Antonelou, Marianna H; Margaritis, Lukas H; Papassideri, Issidora S; Stravopodis, Dimitrios J

2013-02-01

In eukaryotes, the ubiquitin-proteasome machinery regulates a number of fundamental cellular processes through accurate and tightly controlled protein degradation pathways. We have, herein, examined the effects of proteasome functional disruption in Dmp53 (+/+) (wild-type) and Dmp53 (-/-) Drosophila melanogaster fly strains through utilization of Bortezomib, a proteasome-specific inhibitor. We report that proteasome inhibition drastically shortens fly life-span and impairs climbing performance, while it also causes larval lethality and activates developmentally irregular cell death programs during oogenesis. Interestingly, Dmp53 gene seems to play a role in fly longevity and climbing ability. Moreover, Bortezomib proved to induce endoplasmic reticulum (ER) stress that was able to result in the engagement of unfolded protein response (UPR) signaling pathway, as respectively indicated by fly Xbp1 activation and Ref(2)P-containing protein aggregate formation. Larva salivary gland and adult brain both underwent strong ER stress in response to Bortezomib, thus underscoring the detrimental role of proteasome inhibition in larval development and brain function. We also propose that the observed upregulation of autophagy operates as a protective mechanism to "counterbalance" Bortezomib-induced systemic toxicity, which is tightly associated, besides ER stress, with activation of apoptosis, mainly mediated by functional Drice caspase and deregulated dAkt kinase. The reduced life-span of exposed to Bortezomib flies overexpressing Atg1_RNAi or Atg18_RNAi supports the protective nature of autophagy against proteasome inhibition-induced stress. Our data reveal the in vivo significance of proteasome functional integrity as a major defensive system against cellular toxicity likely occurring during critical biological processes and morphogenetic courses.

Role of brassinosteroids in alleviation of phenanthrene–cadmium co-contamination-induced photosynthetic inhibition and oxidative stress in tomato

PubMed Central

Ahammed, Golam Jalal; Yu, Jingquan

2013-01-01

Heavy metal pollution often occurs together with organic contaminants. Brassinosteroids (BRs) induce plant tolerance to several abiotic stresses, including phenanthrene (PHE) and cadmium (Cd) stress. However, the role of BRs in PHE+Cd co-contamination-induced stress amelioration is unknown. Here, the interactive effects of PHE, Cd, and 24-epibrassinolide (EBR; a biologically active BR) were investigated in tomato plants. The application of Cd (100 µM) alone was more phytotoxic than PHE applied alone (100 µM); however, their combined application resulted in slightly improved photosynthetic activity and pigment content compared with Cd alone after a 40 d exposure. Accumulation of reactive oxygen species and membrane lipid peroxidation were induced by PHE and/or Cd; however, the differences in effect were insignificant between Cd and PHE+Cd. The foliar application of EBR (0.1 µM) to PHE- and/or Cd-stressed plants alleviated photosynthetic inhibition and oxidative stress by causing enhancement of the activity of the enzymes and related transcript levels of the antioxidant system, secondary metabolism, and the xenobiotic detoxification system. Additionally, PHE and/or Cd residues were significantly decreased in both the leaves and roots after application of EBR, more specifically in PHE+Cd-stressed plants when treated with EBR, indicating a possible improvement in detoxification of these pollutants. The findings thus suggest a potential interaction of EBR and PHE for Cd stress alleviation. These results advocate a positive role for EBR in reducing pollutant residues for food safety and also strengthening phytoremediation. PMID:23201830

The effect of glucose concentration and sodium phenylbutyrate treatment on mitochondrial bioenergetics and ER stress in 3T3-L1 adipocytes.

PubMed

Tanis, Ross M; Piroli, Gerardo G; Day, Stani D; Frizzell, Norma

2015-01-01

While the 3T3-L1 adipocyte model is routinely used for the study of obesity and diabetes, the mitochondrial respiratory profile in normal versus high glucose has not been examined in detail. We matured adipocytes in normal (5mM) or high (30 mM) glucose and insulin and examined the mitochondrial bioenergetics. We also assessed the requirement for the Unfolded Protein Response (UPR) and ER stress under these conditions. Basal respiration was ~1.7-fold greater in adipocytes that had matured in 30 mM glucose; however, their ability to increase oxygen consumption in response to stress was impaired. Adipogenesis proceeded in both normal and high glucose with concomitant activation of the UPR, but only high glucose was associated with increased levels of ER stress and mitochondrial stress as observed by parallel increases in CHOP and protein succination. Treatment of adipocytes with sodium phenylbutyrate relieved mitochondrial stress through a reduction in mitochondrial respiration. Our data suggests that mitochondrial stress, protein succination and ER stress are uniquely linked in adipocytes matured in high glucose. Copyright © 2014 Elsevier B.V. All rights reserved.

BDNF/TrkB Pathway Mediates the Antidepressant-Like Role of H2S in CUMS-Exposed Rats by Inhibition of Hippocampal ER Stress.

PubMed

Wei, Le; Kan, Li-Yuan; Zeng, Hai-Ying; Tang, Yi-Yun; Huang, Hong-Lin; Xie, Ming; Zou, Wei; Wang, Chun-Yan; Zhang, Ping; Tang, Xiao-Qing

2018-06-01

Our previous works have shown that hydrogen sulfide (H 2 S) significantly attenuates chronic unpredictable mild stress (CUMS)-induced depressive-like behaviors and hippocampal endoplasmic reticulum (ER) stress. Brain-derived neurotrophic factor (BDNF) generates an antidepressant-like effect by its receptor tyrosine protein kinase B (TrkB). We have previously found that H 2 S upregulates the expressions of BDNF and p-TrkB in the hippocampus of CUMS-exposed rats. Therefore, the present work was to explore whether BDNF/TrkB pathway mediates the antidepressant-like role of H 2 S by blocking hippocampal ER stress. We found that treatment with K252a (an inhibitor of BDNF/TrkB pathway) significantly increased the immobility time in the forced swim test and tail suspension test and increased the latency to feed in the novelty-suppressed feeding test in the rats cotreated with sodium hydrosulfide (NaHS, a donor of H 2 S) and CUMS. Similarly, K252a reversed the protective effect of NaHS against CUMS-induced hippocampal ER stress, as evidenced by increases in the levels of ER stress-related proteins, glucose-regulated protein 78, CCAAT/enhancer binding protein homologous protein and cleaved caspase-12. Taken together, our results suggest that BDNF/TrkB pathway plays an important mediatory role in the antidepressant-like action of H 2 S in CUMS-exposed rats, which is by suppression of hippocampal ER stress. These data provide a novel mechanism underlying the protection of H 2 S against CUMS-induced depressive-like behaviors.

Alleviation of drought stress of marigold (Tagetes erecta) plants by using arbuscular mycorrhizal fungi

PubMed Central

Asrar, Abdul-Wasea A.; Elhindi, Khalid M.

2010-01-01

The effect of an arbuscular mycorrhizal fungus “AMF” (Glomus constrictum Trappe) on growth, pigments, and phosphorous content of marigold (Tagetes erecta) plant grown under different levels of drought stress was investigated. The applied drought stress levels reduced growth vigor (i.e. plant height, shoot dry weight, flower diameter as well as its fresh and dry weights) of mycorrhizal and non-mycorrhizal plant as compared to control plant (non-drought stressed plant). The presence of mycorrhizal fungus, however, stimulated all growth parameters of the treated plant comparing to non-mycorrhizal treated plant. The photosynthetic pigments (carotene in flowers and chlorophylls a and b in leaves) were also stimulated by the mycorrhizal fungi of well-watered as well as of water-stressed plants. The total pigments of mycorrhizal plants grown under well-watered conditions were higher than those of non-mycorrhizal ones by 60%. In most cases, drought-stressed mycorrhizal plants were significantly better than those of the non-mycorrhizal plants. So, the overall results suggest that mycorrhizal fungal colonization affects host plant positively on growth, pigments, and phosphorous content, flower quality and thereby alleviates the stress imposed by water with holding. PMID:23961109

Perfluorooctanoic acid exposure induces endoplasmic reticulum stress in the liver and its effects are ameliorated by 4-phenylbutyrate.

PubMed

Yan, Shengmin; Zhang, Hongxia; Wang, Jianshe; Zheng, Fei; Dai, Jiayin

2015-10-01

Perfluoroalkyl acids (PFAAs) are a group of widely used anthropogenic compounds. As one of the most dominant PFAAs, perfluorooctanoic acid (PFOA) has been suggested to induce hepatotoxicity and several other toxicological effects. However, details on the mechanisms for PFOA-induced hepatotoxicity still need to be elucidated. In this study, we observed the occurrence of endoplasmic reticulum (ER) stress in mouse livers and HepG2 cells after PFOA exposure using several familiar markers for the unfolded protein response (UPR). ER stress in HepG2 cells after PFOA exposure was not significantly influenced by autophagy inhibition or stimulation. The antioxidant defense system was significantly disturbed in mouse livers after PFOA exposure, and reactive oxygen species (ROS) were increased in cells exposed to PFOA for 24 h. However, N-acetyl-L-cysteine (NAC) pretreatment did not satisfactorily alleviate the UPR in cells exposed to PFOA even though the increase of ROS was less evident. Furthermore, exposure of HepG2 cells to PFOA in the presence of sodium 4-phenylbutyrate (4-PBA), a chemical chaperone and ER stress inhibitor, suggested that 4-PBA alleviated the UPR and autophagosome accumulation induced by PFOA in cells. In addition, several toxicological effects attributed to PFOA exposure, including cell cycle arrest, proteolytic activity impairment, and neutral lipid accumulation, were also improved by 4-PBA cotreatment in cells. In vivo study demonstrated that PFOA-induced lipid metabolism perturbation and liver injury were partially ameliorated by 4-PBA in mice after 28 days of exposure. These findings demonstrated that PFOA-induced ER stress leading to UPR might play an important role in PFOA-induced hepatotoxic effects, and chemical chaperone 4-PBA could ameliorate the effects. Copyright © 2015. Published by Elsevier Inc.

N-acetylcysteine protects against cadmium-induced germ cell apoptosis by inhibiting endoplasmic reticulum stress in testes.

PubMed

Ji, Yan-Li; Wang, Hua; Zhang, Cheng; Zhang, Ying; Zhao, Mei; Chen, Yuan-Hua; Xu, De-Xiang

2013-03-01

Cadmium (Cd) is a reproductive toxicant that induces germ cell apoptosis in the testes. Previous studies have demonstrated that endoplasmic reticulum (ER) stress is involved in Cd-induced germ cell apoptosis. The aim of the present study was to investigate the effects of N-acetylcysteine (NAC), an antioxidant, on Cd-induced ER stress and germ cell apoptosis in the testes. Male CD-1 mice were intraperitoneally injected with CdCl2 (2.0 mg kg(-1)). As expected, acute Cd exposure induced germ cell apoptosis in the testes, as determined by terminal dUTP nick-end labelling (TUNEL). However, the administration of NAC alleviated Cd-induced germ cell apoptosis in the testes. Further analysis showed that NAC attenuated the Cd-induced upregulation of testicular glucose-regulated protein 78 (GRP78), an important ER molecular chaperone. Moreover, NAC inhibited the Cd-induced phosphorylation of testicular eukaryotic translation initiation factor 2α (eIF2α), a downstream target of the double-stranded RNA-activated kinase-like ER kinase (PERK) pathway. In addition, NAC blocked the Cd-induced activation of testicular X binding protein (XBP)-1, indicating that NAC attenuates the Cd-induced ER stress and the unfolded protein response (UPR). Interestingly, NAC almost completely prevented the Cd-induced elevation of C/EBP homologous protein (CHOP) and phosphorylation of c-Jun N-terminal kinase (JNK), two components of the ER stress-mediated apoptotic pathway. In conclusion, NAC protects against Cd-induced germ cell apoptosis by inhibiting endoplasmic reticulum stress in the testes.

N-acetylcysteine protects against cadmium-induced germ cell apoptosis by inhibiting endoplasmic reticulum stress in testes

PubMed Central

Ji, Yan-Li; Wang, Hua; Zhang, Cheng; Zhang, Ying; Zhao, Mei; Chen, Yuan-Hua; Xu, De-Xiang

2013-01-01

Cadmium (Cd) is a reproductive toxicant that induces germ cell apoptosis in the testes. Previous studies have demonstrated that endoplasmic reticulum (ER) stress is involved in Cd-induced germ cell apoptosis. The aim of the present study was to investigate the effects of N-acetylcysteine (NAC), an antioxidant, on Cd-induced ER stress and germ cell apoptosis in the testes. Male CD-1 mice were intraperitoneally injected with CdCl2 (2.0 mg kg−1). As expected, acute Cd exposure induced germ cell apoptosis in the testes, as determined by terminal dUTP nick-end labelling (TUNEL). However, the administration of NAC alleviated Cd-induced germ cell apoptosis in the testes. Further analysis showed that NAC attenuated the Cd-induced upregulation of testicular glucose-regulated protein 78 (GRP78), an important ER molecular chaperone. Moreover, NAC inhibited the Cd-induced phosphorylation of testicular eukaryotic translation initiation factor 2α (eIF2α), a downstream target of the double-stranded RNA-activated kinase-like ER kinase (PERK) pathway. In addition, NAC blocked the Cd-induced activation of testicular X binding protein (XBP)-1, indicating that NAC attenuates the Cd-induced ER stress and the unfolded protein response (UPR). Interestingly, NAC almost completely prevented the Cd-induced elevation of C/EBP homologous protein (CHOP) and phosphorylation of c-Jun N-terminal kinase (JNK), two components of the ER stress-mediated apoptotic pathway. In conclusion, NAC protects against Cd-induced germ cell apoptosis by inhibiting endoplasmic reticulum stress in the testes. PMID:23353715

The novel white spot syndrome virus-induced gene, PmERP15, encodes an ER stress-responsive protein in black tiger shrimp, Penaeus monodon.

PubMed

Leu, Jiann-Horng; Liu, Kuan-Fu; Chen, Kuan-Yu; Chen, Shu-Hwa; Wang, Yu-Bin; Lin, Chung-Yen; Lo, Chu-Fang

2015-04-01

By microarray screening, we identified a white spot syndrome virus (WSSV)-strongly induced novel gene in gills of Penaeus monodon. The gene, PmERP15, encodes a putative transmembrane protein of 15 kDa, which only showed some degree of similarity (54-59%) to several unknown insect proteins, but had no hits to shrimp proteins. RT-PCR showed that PmERP15 was highly expressed in the hemocytes, heart and lymphoid organs, and that WSSV-induced strong expression of PmERP15 was evident in all tissues examined. Western blot analysis likewise showed that WSSV strongly up-regulated PmERP15 protein levels. In WSSV-infected hemocytes, immunofluorescence staining showed that PmERP15 protein was colocalized with an ER enzyme, protein disulfide isomerase, and in Sf9 insect cells, PmERP15-EGFP fusion protein colocalized with ER -Tracker™ Red dye as well. GRP78, an ER stress marker, was found to be up-regulated in WSSV-infected P. monodon, and both PmERP15 and GRP78 were up-regulated in shrimp injected with ER stress inducers tunicamycin and dithiothreitol. Silencing experiments showed that although PmERP15 dsRNA-injected shrimp succumbed to WSSV infection more rapidly, the WSSV copy number had no significant changes. These results suggest that PmERP15 is an ER stress-induced, ER resident protein, and its induction in WSSV-infected shrimp is caused by the ER stress triggered by WSSV infection. Furthermore, although PmERP15 has no role in WSSV multiplication, its presence is essential for the survival of WSSV-infected shrimp. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fluorescence lifetime imaging of microviscosity changes during ER autophagy in live cells

NASA Astrophysics Data System (ADS)

He, Ying; Samanta, Soham; Gong, Wanjun; Liu, Wufan; Pan, Wenhui; Yang, Zhigang; Qu, Junle

2018-02-01

Unfolded or misfolded protein accumulation inside Endoplasmic Reticulum (ER) will cause ER stress and subsequently will activate cellular autophagy to release ER stress, which would ultimately result in microviscosity changes. However, even though, it is highly significant to gain a quantitative assessment of microviscosity changes during ER autophagy to study ER stress and autophagy behaviors related diseases, it has rarely been reported yet. In this work, we have reported a BODIPY based fluorescent molecular rotor that can covalently bind with vicinal dithiols containing nascent proteins in ER and hence can result in ER stress through the inhibition of the folding of nascent proteins. The change in local viscosity, caused by the release of the stress in cells through autophagy, was quantified by the probe using fluorescence lifetime imaging. This work basically demonstrates the possibility of introducing synthetic chemical probe as a promising tool to diagnose ER-viscosity-related diseases.

Ghrelin alleviates anxiety- and depression-like behaviors induced by chronic unpredictable mild stress in rodents.

PubMed

Huang, Hui-Jie; Zhu, Xiao-Cang; Han, Qiu-Qin; Wang, Ya-Lin; Yue, Na; Wang, Jing; Yu, Rui; Li, Bing; Wu, Gen-Cheng; Liu, Qiong; Yu, Jin

2017-05-30

As a regulator of food intake, ghrelin also plays a key role in mood disorders. Previous studies reported that acute ghrelin administration defends against depressive symptoms of chronic stress. However, the effects of long-term ghrelin on rodents under chronic stress hasn't been revealed. In this study, we found chronic peripheral administration of ghrelin (5nmol/kg/day for 2 weeks, i.p.) could alleviate anxiety- and depression-like behaviors induced by chronic unpredictable mild stress (CUMS). The depression-like behaviors were assessed by the forced swimming test (FST), and anxiety-like behaviors were assessed by the open field test (OFT) and the elevated plus maze test (EPM). Meanwhile, we observed that peripheral acylated ghrelin, together with gastral and hippocampal ghrelin prepropeptide mRNA level, were significantly up-regulated in CUMS mice. Besides, the increased protein level of growth hormone secretagogue receptor (GHSR) in hippocampus were also detected. These results suggested that the endogenous ghrelin/GHSR pathway activated by CUMS plays a role in homeostasis. Further results showed that central treatment of ghrelin (10μg/rat/day for 2 weeks, i.c.v.) or GHRP-6 (the agonist of GHSR, 10μg/rat/day for 2 weeks, i.c.v.) significantly alleviated the depression-like behaviors induced by CUMS in FST and sucrose preference test (SPT). Based on these results, we concluded that central GHSR is involved in the antidepressant-like effect of exogenous ghrelin treatment, and ghrelin/GHSR may have the inherent neuromodulatory properties against depressive symptoms. Copyright © 2017 Elsevier B.V. All rights reserved.

Oxidants produced by methylglyoxal-modified collagen trigger ER stress and apoptosis in skin fibroblasts.

PubMed

Nowotny, Kerstin; Castro, José Pedro; Hugo, Martín; Braune, Sabine; Weber, Daniela; Pignitter, Marc; Somoza, Veronika; Bornhorst, Julia; Schwerdtle, Tanja; Grune, Tilman

2018-05-20

Methylglyoxal (MG), a highly reactive dicarbonyl, interacts with proteins to form advanced glycation end products (AGEs). AGEs include a variety of compounds which were shown to have damaging potential and to accumulate in the course of different conditions such as diabetes mellitus and aging. After confirming collagen as a main target for MG modifications in vivo within the extracellular matrix, we show here that MG-collagen disrupts fibroblast redox homeostasis and induces endoplasmic reticulum (ER) stress and apoptosis. In particular, MG-collagen-induced apoptosis is associated with the activation of the PERK-eIF2α pathway and caspase-12. MG-collagen contributes to altered redox homeostasis by directly generating hydrogen peroxide and oxygen-derived free radicals. The induction of ER stress in human fibroblasts was confirmed using collagen extracts isolated from old mice in which MG-derived AGEs were enriched. In conclusion, MG-derived AGEs represent one factor contributing to diminished fibroblast function during aging. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Trehalose ameliorates oxidative stress-mediated mitochondrial dysfunction and ER stress via selective autophagy stimulation and autophagic flux restoration in osteoarthritis development.

PubMed

Tang, Qian; Zheng, Gang; Feng, Zhenhua; Chen, Yu; Lou, Yiting; Wang, Chenggui; Zhang, Xiaolei; Zhang, Yu; Xu, Huazi; Shang, Ping; Liu, Haixiao

2017-10-05

Oxidative stress-related apoptosis and autophagy play crucial roles in the development of osteoarthritis (OA), a progressive cartilage degenerative disease with multifactorial etiologies. Here, we determined autophagic flux changes and apoptosis in human OA and tert-Butyl hydroperoxide (TBHP)-treated chondrocytes. In addition, we explored the potential protective effects of trehalose, a novel Mammalian Target of Rapamycin (mTOR)-independent autophagic inducer, in TBHP-treated mouse chondrocytes and a destabilized medial meniscus (DMM) mouse OA model. We found aberrant p62 accumulation and increased apoptosis in human OA cartilage and chondrocytes. Consistently, p62 and cleaved caspase-3 levels increased in mouse chondrocytes under oxidative stress. Furthermore, trehalose restored oxidative stress-induced autophagic flux disruption and targeted autophagy selectively by activating BCL2 interacting protein 3 (BNIP3) and Phosphoglycerate mutase family member 5 (PGAM5). Trehalose could ameliorate oxidative stress-mediated mitochondrial membrane potential collapse, ATP level decrease, dynamin-related protein 1 (drp-1) translocation into the mitochondria, and the upregulation of proteins involved in mitochondria and endoplasmic reticulum (ER) stress-related apoptosis pathway. In addition, trehalose suppressed the cleavage of caspase 3 and poly(ADP-ribose) polymerase (PARP) and prevented DNA damage under oxidative stress. However, the anti-apoptotic effects of trehalose in TBHP-treated chondrocytes were partially abolished by autophagic flux inhibitor chloroquine and BNIP3- siRNA. The protective effect of trehalose was also found in mouse OA model. Taken together, these results indicate that trehalose has anti-apoptotic effects through the suppression of oxidative stress-induced mitochondrial injury and ER stress which is dependent on the promotion of autophagic flux and the induction of selective autophagy. Thus, trehalose is a promising therapeutic agent for OA.

Alleviation of Salt Stress in Pepper (Capsicum annum L.) Plants by Plant Growth-Promoting Rhizobacteria.

PubMed

Hahm, Mi-Seon; Son, Jin-Soo; Hwang, Ye-Ji; Kwon, Duk-Kee; Ghim, Sa-Youl

2017-10-28

In the present study, we demonstrate that the growth of salt-stressed pepper plants is improved by inoculation with plant growth-promoting rhizobacteria (PGPR). Three PGPR strains ( Microbacterium oleivorans KNUC7074, Brevibacterium iodinum KNUC7183, and Rhizobium massiliae KNUC7586) were isolated from the rhizosphere of pepper plants growing in saline soil, and pepper plants inoculated with these PGPR strains exhibited significantly greater plant height, fresh weight, dry weight, and total chlorophyll content than non-inoculated plants. In addition, salt-stressed pepper plants that were inoculated with B. iodinum KNUC7183 and R. massiliae KNUC7586 possessed significantly different total soluble sugar and proline contents from non-inoculated controls, and the activity of several antioxidant enzymes (ascorbate peroxidase, guaiacol peroxidase, and catalase) was also elevated in PGPR-treated plants under salt stress. Overall, these results suggest that the inoculation of pepper plants with M. oleivorans KNUC7074, B. iodinum KNUC7183, and R. massiliae KNUC7586 can alleviate the harmful effects of salt stress on plant growth.

Programming of Fetal Insulin Resistance in Pregnancies with Maternal Obesity by ER Stress and Inflammation

PubMed Central

Sáez, Pablo J.; Villalobos-Labra, Roberto; Farías-Jofré, Marcelo

2014-01-01

The global epidemics of obesity during pregnancy and excessive gestational weight gain (GWG) are major public health problems worldwide. Obesity and excessive GWG are related to several maternal and fetal complications, including diabetes (pregestational and gestational diabetes) and intrauterine programming of insulin resistance (IR). Maternal obesity (MO) and neonatal IR are associated with long-term development of obesity, diabetes mellitus, and increased global cardiovascular risk in the offspring. Multiple mechanisms of insulin signaling pathway impairment have been described in obese individuals, involving complex interactions of chronically elevated inflammatory mediators, adipokines, and the critical role of the endoplasmic reticulum (ER) stress-dependent unfolded protein response (UPR). However, the underlying cellular processes linking MO and IR in the offspring have not been fully elucidated. Here, we summarize the state-of-the-art evidence supporting the possibility that adverse metabolic postnatal outcomes such as IR in the offspring of pregnancies with MO and/or excessive GWG may be related to intrauterine activation of ER stress response. PMID:25093191

Xbp1s in Pomc neurons connects ER stress with energy balance and glucose homeostasis.

PubMed

Williams, Kevin W; Liu, Tiemin; Kong, Xingxing; Fukuda, Makoto; Deng, Yingfeng; Berglund, Eric D; Deng, Zhuo; Gao, Yong; Liu, Tianya; Sohn, Jong-Woo; Jia, Lin; Fujikawa, Teppei; Kohno, Daisuke; Scott, Michael M; Lee, Syann; Lee, Charlotte E; Sun, Kai; Chang, Yongsheng; Scherer, Philipp E; Elmquist, Joel K

2014-09-02

The molecular mechanisms underlying neuronal leptin and insulin resistance in obesity and diabetes remain unclear. Here we show that induction of the unfolded protein response transcription factor spliced X-box binding protein 1 (Xbp1s) in pro-opiomelanocortin (Pomc) neurons alone is sufficient to protect against diet-induced obesity as well as improve leptin and insulin sensitivity, even in the presence of strong activators of ER stress. We also demonstrate that constitutive expression of Xbp1s in Pomc neurons contributes to improved hepatic insulin sensitivity and suppression of endogenous glucose production. Notably, elevated Xbp1s levels in Pomc neurons also resulted in activation of the Xbp1s axis in the liver via a cell-nonautonomous mechanism. Together our results identify critical molecular mechanisms linking ER stress in arcuate Pomc neurons to acute leptin and insulin resistance as well as liver metabolism in diet-induced obesity and diabetes. Copyright © 2014 Elsevier Inc. All rights reserved.

Silicon improves seed germination and alleviates oxidative stress of bud seedlings in tomato under water deficit stress.

PubMed

Shi, Yu; Zhang, Yi; Yao, Hejin; Wu, Jiawen; Sun, Hao; Gong, Haijun

2014-05-01

The beneficial effects of silicon on plant growth and development under drought have been widely reported. However, little information is available on the effects of silicon on seed germination under drought. In this work, the effects of exogenous silicon (0.5 mM) on the seed germination and tolerance performance of tomato (Solanum lycopersicum L.) bud seedlings under water deficit stress simulated by 10% (w/v) polyethylene glycol (PEG-6000) were investigated in four cultivars ('Jinpengchaoguan', 'Zhongza No.9', 'Houpi L402' and 'Oubao318'). The results showed that the seed germination percentage was notably decreased in the four cultivars under water stress, and it was significantly improved by added silicon. Compared with the non-silicon treatment, silicon addition increased the activities of superoxide dismutase (SOD) and catalase (CAT), and decreased the production of superoxide anion (O2·) and hydrogen peroxide (H2O2) in the radicles of bud seedlings under water stress. Addition of silicon decreased the total phenol concentrations in radicles under water stress, which might contribute to the decrease of peroxidase (POD) activity, as observed in the in vivo and in vitro experiments. The decrease of POD activity might contribute to a less accumulation of hydroxyl radical (·OH) under water stress. Silicon addition also decreased the concentrations of malondialdehyde (MDA) in the radicles under stress, indicating decreased lipid peroxidation. These results suggest that exogenous silicon could improve seed germination and alleviate oxidative stress to bud seedling of tomato by enhancing antioxidant defense. The positive effects of silicon observed in a silicon-excluder also suggest the active involvement of silicon in biochemical processes in plants. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Flurbiprofen ameliorated obesity by attenuating leptin resistance induced by endoplasmic reticulum stress.

PubMed

Hosoi, Toru; Yamaguchi, Rie; Noji, Kikuko; Matsuo, Suguru; Baba, Sachiko; Toyoda, Keisuke; Suezawa, Takahiro; Kayano, Takaaki; Tanaka, Shinpei; Ozawa, Koichiro

2014-03-01

Endoplasmic reticulum (ER) stress, caused by the accumulation of unfolded proteins, is involved in the development of obesity. We demonstrated that flurbiprofen, a nonsteroidal anti-inflammatory drug (NSAID), exhibited chaperone activity, which reduced protein aggregation and alleviated ER stress-induced leptin resistance, characterized by insensitivity to the actions of the anti-obesity hormone leptin. This result was further supported by flurbiprofen attenuating high-fat diet-induced obesity in mice. The other NSAIDs tested did not exhibit such effects, which suggested that this anti-obesity action is mediated independent of NSAIDs. Using ferriteglycidyl methacrylate beads, we identified aldehyde dehydrogenase as the target of flurbiprofen, but not of the other NSAIDs. These results suggest that flurbiprofen may have unique pharmacological properties that reduce the accumulation of unfolded proteins and may represent a new class of drug for the fundamental treatment of obesity.

Turning Anxiety into Creativity: Using Postmodern Principles to Alleviate Anxiety and Stress through the Art Curriculum and Beyond

ERIC Educational Resources Information Center

Ferry, Lisa Marie

2016-01-01

The purpose of this action research study is to help students alleviate their anxiety and stress symptoms using activities based on Olivia Gude's postmodern principles. The activities included are the participants own take-along visual art journal kit and classroom projects. Professional learning outcomes include the knowledge to equip teachers…

The CDK inhibitor p21 is a novel target gene of ATF4 and contributes to cell survival under ER stress.

PubMed

Inoue, Yasumichi; Kawachi, Shiori; Ohkubo, Tsubasa; Nagasaka, Mai; Ito, Shogo; Fukuura, Keishi; Itoh, Yuka; Ohoka, Nobumichi; Morishita, Daisuke; Hayashi, Hidetoshi

2017-11-01

Activating transcription factor 4 (ATF4) is well known for its role in the endoplasmic reticulum (ER) stress response. ATF4 also transcriptionally induces multiple effectors that determine cell fate depending on cellular context. In addition, ATF4 can communicate both pro-apoptotic and pro-survival signals. How ATF4 mediates its prosurvival roles, however, requires further investigation. Here, we report that the CDK inhibitor p21 is a novel target gene of ATF4. We identified two ATF4-responsive elements, one of which directly binds ATF4, within the first intron of the p21 gene. Importantly, overexpression of p21 enhances cell survival following ER stress induction, while p21 knockdown increases cell death. These results suggest that p21 induction plays a vital role in the cellular response to ER stress and indicate that p21 is a prosurvival effector of ATF4. © 2017 Federation of European Biochemical Societies.

Endoplasmic reticulum stress (ER-stress) by 2-deoxy-D-glucose (2DG) reduces cyclooxygenase-2 (COX-2) expression and N-glycosylation and induces a loss of COX-2 activity via a Src kinase-dependent pathway in rabbit articular chondrocytes.

PubMed

Yu, Seon-Mi; Kim, Song-Ja

2010-11-30

Endoplasmic reticulum (ER) stress regulates a wide range of cellular responses including apoptosis, proliferation, inflammation, and differentiation in mammalian cells. In this study, we observed the role of 2-deoxy-D-glucose (2DG) on inflammation of chondrocytes. 2DG is well known as an inducer of ER stress, via inhibition of glycolysis and glycosylation. Treatment of 2DG in chondrocytes considerably induced ER stress in a dose- and time-dependent manner, which was demonstrated by a reduction of glucose regulated protein of 94 kDa (grp94), an ER stress-inducible protein, as determined by a Western blot analysis. In addition, induction of ER stress by 2DG led to the expression of COX-2 protein with an apparent molecular mass of 66-70kDa as compared with the normally expressed 72-74 kDa protein. The suppression of ER stress with salubrinal (Salub), a selective inhibitor of eif2-alpha dephosphorylation, successfully prevented grp94 induction and efficiently recovered 2DG- modified COX-2 molecular mass and COX-2 activity might be associated with COX-2 N-glycosylation. Also, treatment of 2DG increased phosphorylation of Src in chondrocytes. The inhibition of the Src signaling pathway with PP2 (Src tyrosine kinase inhibitor) suppressed grp94 expression and restored COX-2 expression, N-glycosylation, and PGE2 production, as determined by a Western blot analysis and PGE2 assay. Taken together, our results indicate that the ER stress induced by 2DG results in a decrease of the transcription level, the molecular mass, and the activity of COX-2 in rabbit articular chondrocytes via a Src kinase-dependent pathway.

Selenium alleviates chromium toxicity by preventing oxidative stress in cabbage (Brassica campestris L. ssp. Pekinensis) leaves.

PubMed

Qing, Xuejiao; Zhao, Xiaohu; Hu, Chengxiao; Wang, Peng; Zhang, Ying; Zhang, Xuan; Wang, Pengcheng; Shi, Hanzhi; Jia, Fen; Qu, Chanjuan

2015-04-01

The beneficial role of selenium (Se) in alleviation of chromium (Cr)-induced oxidative stress is well established. However, little is known about the underlying mechanism. The impacts of exogenous Se (0.1mg/L) on Cr(1mg/L)-induced oxidative stress and antioxidant systems in leaves of cabbage (Brassica campestris L. ssp. Pekinensis) were investigated by using cellular and biochemical approaches. The results showed that supplementation of the medium with Se was effective in reducing Cr-induced increased levels of lipid peroxides and superoxide free radicals (O(-)2(·)), as well as increasing activities of superoxide dismutase (SOD) and peroxidase (POD). Meanwhile, 1mg/L Cr induced loss of plasma membrane integrity, growth inhibition, as well as ultrastructural changes of leaves were significantly reversed due to Se supplementation in the medium. In addition, Se application significantly altered the subcellular distribution of Cr which transported from mitochondria, nucleus and the cell-wall material to the soluble fraction and chloroplasts. However, Se application did no significant alteration of Cr effects on osmotic adjustment accumulating products. The study suggested that Se is able to protect leaves of cabbage against Cr toxicity by alleviation of Cr induced oxidative stress, and re-distribution of Cr in the subcellular of the leaf. Furthermore, free radicals, lipid peroxides, activity of SOD and POD, and subcellular distribution of Cr can be considered the efficient biomarkers to indicate the efficiency of Se to detoxification Cr. Copyright © 2015 Elsevier Inc. All rights reserved.

Curcumin derivative WZ35 efficiently suppresses colon cancer progression through inducing ROS production and ER stress-dependent apoptosis.

PubMed

Zhang, Junru; Feng, Zhiguo; Wang, Chunhua; Zhou, Huiping; Liu, Weidong; Kanchana, Karvannan; Dai, Xuanxuan; Zou, Peng; Gu, Junlian; Cai, Lu; Liang, Guang

2017-01-01

Colon cancer is characterized by its fast progression and poor prognosis, and novel agents of treating colon cancer are urgently needed. WZ35, a synthetic curcumin derivative, has been reported to exhibit promising antitumor activity. Here, we investigated the in vitro and in vivo activities of WZ35 and explored the underlying mechanisms in colon cancer cell lines. WZ35 treatment significantly decreased the cell viability associated with G2/M cell cycle arrest and apoptosis induction in colon cancer cell lines. We also show that WZ35 is highly effective in inhibiting tumor growth in a CT26 xenograft mouse model. Mechanistically, WZ35 treatment significantly induced reactive oxygen species (ROS) generation and endoplasmic reticulum (ER) stress in CT26 cells. Abrogation of ROS production by N-acetylcysteine (NAC) co-treatment almost totally reversed the WZ35-induced cell apoptosis and ER stress activation. Inhibition of p-PERK by GSK2606414 can significantly reverse WZ35-induced cell apoptosis in CT26 cells. Taken together, the curcumin derivative WZ35 exhibited anti-tumor effects in colon cancer cells both in vitro and in vivo, via a ROS-ER stress-mediated mechanism. These findings indicate that activating ROS generation could be an important strategy for the treatment of colon cancers.

The metabolic ER stress sensor IRE1α suppresses alternative activation of macrophages and impairs energy expenditure in obesity.

PubMed

Shan, Bo; Wang, Xiaoxia; Wu, Ying; Xu, Chi; Xia, Zhixiong; Dai, Jianli; Shao, Mengle; Zhao, Feng; He, Shengqi; Yang, Liu; Zhang, Mingliang; Nan, Fajun; Li, Jia; Liu, Jianmiao; Liu, Jianfeng; Jia, Weiping; Qiu, Yifu; Song, Baoliang; Han, Jing-Dong J; Rui, Liangyou; Duan, Sheng-Zhong; Liu, Yong

2017-05-01

Obesity is associated with metabolic inflammation and endoplasmic reticulum (ER) stress, both of which promote metabolic disease progression. Adipose tissue macrophages (ATMs) are key players orchestrating metabolic inflammation, and ER stress enhances macrophage activation. However, whether ER stress pathways underlie ATM regulation of energy homeostasis remains unclear. Here, we identified inositol-requiring enzyme 1α (IRE1α) as a critical switch governing M1-M2 macrophage polarization and energy balance. Myeloid-specific IRE1α abrogation in Ern1 f/f ; Lyz2-Cre mice largely reversed high-fat diet (HFD)-induced M1-M2 imbalance in white adipose tissue (WAT) and blocked HFD-induced obesity, insulin resistance, hyperlipidemia and hepatic steatosis. Brown adipose tissue (BAT) activity, WAT browning and energy expenditure were significantly higher in Ern1 f/f ; Lyz2-Cre mice. Furthermore, IRE1α ablation augmented M2 polarization of macrophages in a cell-autonomous manner. Thus, IRE1α senses protein unfolding and metabolic and immunological states, and consequently guides ATM polarization. The macrophage IRE1α pathway drives obesity and metabolic syndrome through impairing BAT activity and WAT browning.

Humic Acid Increases Amyloid β-Induced Cytotoxicity by Induction of ER Stress in Human SK-N-MC Neuronal Cells

PubMed Central

Li, Hsin-Hua; Lu, Fung-Jou; Hung, Hui-Chih; Liu, Guang-Yaw; Lai, Te-Jen; Lin, Chih-Li

2015-01-01

Humic acid (HA) is a possible etiological factor associated with for several vascular diseases. It is known that vascular risk factors can directly increase the susceptibility to Alzheimer’s disease (AD), which is a neurodegenerative disorder due to accumulation of amyloid β (Aβ) peptide in the brain. However, the role that HA contributes to Aβ-induced cytotoxicity has not been demonstrated. In the present study, we demonstrate that HA exhibits a synergistic effect enhancing Aβ-induced cytotoxicity in cultured human SK-N-MC neuronal cells. Furthermore, this deterioration was mediated through the activation of endoplasmic reticulum (ER) stress by stimulating PERK and eIF2α phosphorylation. We also observed HA and Aβ-induced cytotoxicity is associated with mitochondrial dysfunction caused by down-regulation of the Sirt1/PGC1α pathway, while in contrast, treating the cells with the ER stress inhibitor Salubrinal, or over-expression of Sirt1 significantly reduced loss of cell viability by HA and Aβ. Our findings suggest a new mechanism by which HA can deteriorate Aβ-induced cytotoxicity through modulation of ER stress, which may provide significant insights into the pathogenesis of AD co-occurring with vascular injury. PMID:25961951

Endoplasmic reticulum Chaperon Tauroursodeoxycholic Acid Alleviates Obesity-Induced Myocardial Contractile Dysfunction

PubMed Central

Ceylan-Isik, Asli F.; Sreejayan, Nair; Ren, Jun

2010-01-01

ER stress is involved in the pathophysiology of obesity although little is known about the role of ER stress on obesity-associated cardiac dysfunction. This study was designed to examine the effect of ER chaperone tauroursodeoxycholic acid (TUDCA) on obesity-induced myocardial dysfunction. Adult lean and ob/ob obese mice were treated TUDCA (50 mg/kg/d, p.o.) or vehicle for 5 wks. Oral glucose tolerance test (OGTT) was performed. Echocardiography, cardiomyocyte contractile and intracellular Ca2+ properties were assessed. Sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) activity and protein expression of intracellular Ca2+ regulatory proteins were measured using 45Ca2+ uptake and Western blot analysis, respectively. Insulin signaling, ER stress markers and HSP90 were evaluated. Our results revealed that chronic TUDCA treatment lower systolic blood pressure and lessened glucose intolerance in obese mice. Obesity led to increased diastolic diameter, cardiac hypertrophy, compromised fractional shortening, cardiomyocyte contractile (peak shortening, maximal velocity of shortening/relengthening, and duration of contraction/relaxation) and intracellular Ca2+ properties, all of which were significantly attenuated by TUDCA. TUDCA reconciled obesity-associated decreased in SERCA activity and expression, and increase in serine phosphorylation of IRS, total and phosphorylated cJun, ER stress markers Bip, peIF2α and pPERK. Obesity-induced changes in phospholamban and HSP90 were unaffected by TUDCA. In vitro finding revealed that TUDCA ablated palmitic acid-induced cardiomyocyte contractile dysfunction. In summary, these data depicted a pivotal role of ER stress in obesity-associated cardiac contractile dysfunction, suggesting the therapeutic potential of ER stress as a target in the management of cardiac dysfunction in obesity. PMID:21035453

Fluoride induces endoplasmic reticulum stress and inhibits protein synthesis and secretion.

PubMed

Sharma, Ramaswamy; Tsuchiya, Masahiro; Bartlett, John D

2008-09-01

Exposure to excessive amounts of fluoride (F(-)) causes dental fluorosis in susceptible individuals; however, the mechanism of F(-)-induced toxicity is unclear. Previously, we have shown that high-dose F(-) activates the unfolded protein response (UPR) in ameloblasts that are responsible for dental enamel formation. The UPR is a signaling pathway responsible for either alleviating endoplasmic reticulum (ER) stress or for inducing apoptosis of the stressed cells. In this study we determined if low-dose F(-) causes ER stress and activates the UPR, and we also determined whether F(-) interferes with the secretion of proteins from the ER. We stably transfected the ameloblast-derived LS8 cell line with secreted alkaline phosphatase (SEAP) and determined activity and localization of SEAP and F(-)-mediated induction of UPR proteins. Also, incisors from mice given drinking water containing various concentrations of F(-) were examined for eucaryotic initiation factor-2, subunit alpha (eIF2alpha) phosphorylation. We found that F(-) decreases the extracellular secretion of SEAP in a linear, dose-dependent manner. We also found a corresponding increase in the intracellular accumulation of SEAP after exposure to F(-). These changes are associated with the induction of UPR proteins such as the molecular chaperone BiP and phosphorylation of the UPR sensor PKR-like ER kinase, and its substrate, eIF2alpha. Importantly, F(-)-induced phosphorylation of eIF2alphawas confirmed in vivo. These data suggest that F(-) initiates an ER stress response in ameloblasts that interferes with protein synthesis and secretion. Consequently, ameloblast function during enamel development may be impaired, and this may culminate in dental fluorosis.

Fluoride Induces Endoplasmic Reticulum Stress and Inhibits Protein Synthesis and Secretion

PubMed Central

Sharma, Ramaswamy; Tsuchiya, Masahiro; Bartlett, John D.

2008-01-01

Background Exposure to excessive amounts of fluoride (F−) causes dental fluorosis in susceptible individuals; however, the mechanism of F−-induced toxicity is unclear. Previously, we have shown that high-dose F− activates the unfolded protein response (UPR) in ameloblasts that are responsible for dental enamel formation. The UPR is a signaling pathway responsible for either alleviating endoplasmic reticulum (ER) stress or for inducing apoptosis of the stressed cells. Objectives In this study we determined if low-dose F− causes ER stress and activates the UPR, and we also determined whether F− interferes with the secretion of proteins from the ER. Methods We stably transfected the ameloblast-derived LS8 cell line with secreted alkaline phosphatase (SEAP) and determined activity and localization of SEAP and F−-mediated induction of UPR proteins. Also, incisors from mice given drinking water containing various concentrations of F− were examined for eucaryotic initiation factor-2, subunit alpha (eIF2α) phosphorylation. Results We found that F− decreases the extracellular secretion of SEAP in a linear, dose-dependent manner. We also found a corresponding increase in the intracellular accumulation of SEAP after exposure to F−. These changes are associated with the induction of UPR proteins such as the molecular chaperone BiP and phosphorylation of the UPR sensor PKR-like ER kinase, and its substrate, eIF2α. Importantly, F−-induced phosphorylation of eIF2αwas confirmed in vivo. Conclusions These data suggest that F− initiates an ER stress response in ameloblasts that interferes with protein synthesis and secretion. Consequently, ameloblast function during enamel development may be impaired, and this may culminate in dental fluorosis. PMID:18795154

Human leptin protein activates the growth of HepG2 cells by inhibiting PERK‑mediated ER stress and apoptosis.

PubMed

Xiong, Ying; Zhang, Jie; Liu, Man; An, Mingwei; Lei, Ling; Guo, Wuhua

2014-09-01

Current treatment modalities for various types of hepatic cancer, which has an increasing incidence rate, are inadequate and novel therapies are required. Therefore, identifying targets for liver cancer is becoming increasingly valuable to develop novel methods for therapy. The aim of the present study was to examine the growth activation mechanism of the leptin protein in the liver cancer cell line HepG2. The effects of the leptin protein on cell death were investigated by 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide analysis. DNA fragmentation and terminal deoxynucleotidyl transferase dUTP nick end labeling analysis were also performed to detect cell apoptosis. The expression of leptin and three endoplasmic reticulum (ER) stress unfolded protein response (UPR) proteins, including activating transcription factor 6, phosphorylated‑PKR‑like ER kinase (p‑PERK) and inositol requiring protein 1, were investigated for the examination of ER stress. The mRNA UPR proteins were also detected by reverse transcription polymerase chain reaction. The apoptosis‑associated caspase 12 and C/EBP homologous protein (CHOP) was detected by western blot analysis. The expression of or incubation with the leptin protein was able to activate cell growth and inhibit cell death and apoptosis. In cells that expressed leptin or were incubated with leptin protein (pep-LPT), cisplatin‑induced ER stress‑associated mRNA transcription and protein activation were inhibited. Levels of the ER stress UPR pathway protein, PERK, increased significantly in leptin‑silenced cells when treated with cisplatin as compared with those in the leptin‑expressing or pep-LPT cells. Furthermore, caspase 12 activation was inhibited in ex‑LPT, pep‑LPT and HepG2 cells. In conclusion, human leptin protein is involved in promoting the proliferation of HepG2 cells through inhibiting the ER stress‑associated apoptotic pathway. The PERK UPR pathway and the apoptotic factor

β-aminobutyric acid mediated drought stress alleviation in maize (Zea mays L.).

PubMed

Shaw, Arun K; Bhardwaj, Pardeep K; Ghosh, Supriya; Roy, Sankhajit; Saha, Suman; Sherpa, Ang R; Saha, Samir K; Hossain, Zahed

2016-02-01

The present study highlights the role of β-aminobutyric acid (BABA) in alleviating drought stress effects in maize (Zea mays L.). Chemical priming was imposed by pretreating 1-week-old plants with 600 μM BABA prior to applying drought stress. Specific activities of key antioxidant enzymes and metabolites (ascorbate and glutathione) levels of ascorbate-glutathione cycle were studied to unravel the priming-induced modulation of plant defense system. Furthermore, changes in endogenous ABA and JA concentrations as well as mRNA expressions of key genes involved in their respective biosynthesis pathways were monitored in BABA-primed (BABA+) and non-primed (BABA-) leaves of drought-challenged plants to better understand the mechanistic insights into the BABA-induced hormonal regulation of plant response to water-deficit stress. Accelerated stomatal closure, high relative water content, and less membrane damage were observed in BABA-primed leaves under water-deficit condition. Elevated APX and SOD activity in non-primed leaves found to be insufficient to scavenge all H2O2 and O2 (·-) resulting in oxidative burst as evident after histochemical staining with NBT and DAB. A higher proline accumulation in non-primed leaves also does not give much protection against drought stress. Increased GR activity supported with the enhanced mRNA and protein expressions might help the BABA-primed plants to maintain a high GSH pool essential for sustaining balanced redox status to counter drought-induced oxidative stress damages. Hormonal analysis suggests that in maize, BABA-potentiated drought tolerance is primarily mediated through JA-dependent pathway by the activation of antioxidant defense systems while ABA biosynthesis pathway also plays an important role in fine-tuning of drought stress response.

Jolkinolide B induces apoptosis of colorectal carcinoma through ROS-ER stress-Ca2+-mitochondria dependent pathway

PubMed Central

Zhang, Jing; Wang, Yang; Zhou, Ye; He, Qing-Yu

2017-01-01

Colorectal carcinoma (CRC) remains one of the leading causes of death in cancer-related diseases. In this study, we aimed to investigate the anticancer effect of Jolkinolide B (JB), a bioactive diterpenoid component isolated from the dried roots of Euphorbia fischeriana Steud, on CRC cells and its underlying mechanisms. We found that JB suppressed the cell viability and colony formation of CRC cells, HT29 and SW620. Annexin V/PI assay revealed that JB induced apoptosis in CRC cells, which was further confirmed by the increased expression of cleaved-caspase3 and cleaved-PARP. iTRAQ-based quantitative proteomics was performed to identify JB-regulated proteins in CRC cells. Gene Ontology (GO) analysis revealed that these JB-regulated proteins were mainly involved in ER stress response, which was evidenced by the expression of ER stress marker proteins, HSP90, Bip and PDI. Moreover, we found that JB provoked the generation of reactive oxygen species (ROS), and that inhibition of the ROS generation with N-acetyl L-cysteine could reverse the JB-induced apoptosis. Confocal microscopy and flow cytometry showed that JB treatment enhanced intracellular and mitochondrial Ca2+ level and JC-1 assay revealed a loss of mitochondrial membrane potential in CRC after JB treatment. The mitochondrial Ca2+ uptake and depolarization can be blocked by Ruthenium Red (RuRed), an inhibitor of mitochondrial Ca2+ uniporter. Taken together, we demonstrated that JB exerts its anticancer effect by ER stress-Ca2+-mitochondria signaling, suggesting the promising chemotherapeutic potential of JB for the treatment of CRC. PMID:29207638

Jolkinolide B induces apoptosis of colorectal carcinoma through ROS-ER stress-Ca2+-mitochondria dependent pathway.

PubMed

Zhang, Jing; Wang, Yang; Zhou, Ye; He, Qing-Yu

2017-10-31

Colorectal carcinoma (CRC) remains one of the leading causes of death in cancer-related diseases. In this study, we aimed to investigate the anticancer effect of Jolkinolide B (JB), a bioactive diterpenoid component isolated from the dried roots of Euphorbia fischeriana Steud, on CRC cells and its underlying mechanisms. We found that JB suppressed the cell viability and colony formation of CRC cells, HT29 and SW620. Annexin V/PI assay revealed that JB induced apoptosis in CRC cells, which was further confirmed by the increased expression of cleaved-caspase3 and cleaved-PARP. iTRAQ-based quantitative proteomics was performed to identify JB-regulated proteins in CRC cells. Gene Ontology (GO) analysis revealed that these JB-regulated proteins were mainly involved in ER stress response, which was evidenced by the expression of ER stress marker proteins, HSP90, Bip and PDI. Moreover, we found that JB provoked the generation of reactive oxygen species (ROS), and that inhibition of the ROS generation with N-acetyl L-cysteine could reverse the JB-induced apoptosis. Confocal microscopy and flow cytometry showed that JB treatment enhanced intracellular and mitochondrial Ca 2+ level and JC-1 assay revealed a loss of mitochondrial membrane potential in CRC after JB treatment. The mitochondrial Ca 2+ uptake and depolarization can be blocked by Ruthenium Red (RuRed), an inhibitor of mitochondrial Ca 2+ uniporter. Taken together, we demonstrated that JB exerts its anticancer effect by ER stress-Ca 2+ -mitochondria signaling, suggesting the promising chemotherapeutic potential of JB for the treatment of CRC.

An inducible ER–Golgi tether facilitates ceramide transport to alleviate lipotoxicity

PubMed Central

Choudhary, Vineet

2017-01-01

Ceramides are key intermediates in sphingolipid biosynthesis and potent signaling molecules. However, excess ceramide is toxic, causing growth arrest and apoptosis. In this study, we identify a novel mechanism by which cells prevent the toxic accumulation of ceramides; they facilitate nonvesicular ceramide transfer from the endoplasmic reticulum (ER) to the Golgi complex, where ceramides are converted to complex sphingolipids. We find that the yeast protein Nvj2p promotes the nonvesicular transfer of ceramides from the ER to the Golgi complex. The protein is a tether that generates close contacts between these compartments and may directly transport ceramide. Nvj2p normally resides at contacts between the ER and other organelles, but during ER stress, it relocalizes to and increases ER–Golgi contacts. ER–Golgi contacts fail to form during ER stress in cells lacking Nvj2p. Our findings demonstrate that cells regulate ER–Golgi contacts in response to stress and reveal that nonvesicular ceramide transfer out of the ER prevents the buildup of toxic amounts of ceramides. PMID:28011845

Methylglyoxal alleviates cadmium toxicity in wheat (Triticum aestivum L).

PubMed

Li, Zhong-Guang; Duan, Xiang-Qiu; Xia, Yan-Mei; Wang, Yue; Zhou, Zhi-Hao; Min, Xiong

2017-02-01

Methylglyoxal alleviates cadmium toxicity in wheat (Triticum aestivum L) by improving plant growth. For a long time, the reactive α, β-carbonyl ketoaldehyde methylglyoxal (CH3COCHO; MG) has been regarded as merely a toxic metabolite in plants, but, now, emerging as a signal molecule in plants. In this study, cadmium (Cd) stress decreased plant height, root length, fresh weight (FW), and dry weight (DW) in a concentration-dependent manner, indicating that Cd had toxic effects on the growth of wheat seedlings. The toxic effects of Cd were alleviated by exogenously applied MG in a dosage dependent fashion, and 700 mM MG reached significant differences, but this alleviating effect was eliminated by the treatment with N-acetyl-L-cysteine (NAC, MG scavenger), suggesting that MG could mitigate Cd toxicity in wheat. This study reported for the first time that MG could alleviate Cd toxicity in wheat, uncovering a new possible physiological function for MG, and opening a novel line of research in plant stress biology.

Resveratrol Induces Cancer Cell Apoptosis through MiR-326/PKM2-Mediated ER Stress and Mitochondrial Fission.

PubMed

Wu, Haili; Wang, Yingying; Wu, Changxin; Yang, Peng; Li, Hanqing; Li, Zhuoyu

2016-12-14

Resveratrol (Res), a natural phytoalexin found in a variety of plants, has significant antitumor activity. Pyruvate kinase M2 (PKM2) has abnormally high expression in various tumor cells, and it has been implicated in the survival of tumors. However, whether and how Res inhibits PKM2 expression is poorly understood. In the present study, we found that treatment with Res inhibited cell proliferation and induced cell apoptosis. The IC 50 values of Res against DLD1, HeLa, and MCF-7 cells were 75 ± 4.54, 50 ± 3.65, and 50 ± 3.32 μM, respectively. To elucidate mechanisms underlying its antitumor activities, serial experiments were performed. Results showed that reduction of PKM2 expression in tumor cells by Res treatment increased the expression of ER stress and mitochondrial fission proteins but reduced cell viability and the levels of fusion proteins. These phenomena were reversed by artificial overexpression of PKM2. Quantitative analyses showed that the expression of microRNA-326 (miR-326) was increased upon Res treatment. Treatment with the miR-326 mimic reduced PKM2 expression, promoting recovery from ER stress and mitochondrial fission. Overall, these results demonstrate that miR-326/PKM2-mediated ER stress and mitochondrial dysfunction participate in apoptosis induced by Res. These results provide novel insight into the molecular mechanisms by which Res suppresses tumors and further support for the use of Res as an antitumor drug.

Tauroursodeoxycholic acid dampens oncogenic apoptosis induced by endoplasmic reticulum stress during hepatocarcinogen exposure

PubMed Central

Vandewynckel, Yves-Paul; Laukens, Debby; Devisscher, Lindsey; Paridaens, Annelies; Bogaerts, Eliene; Verhelst, Xavier; Van den Bussche, Anja; Raevens, Sarah; Van Steenkiste, Christophe; Van Troys, Marleen; Ampe, Christophe; Descamps, Benedicte; Vanhove, Chris; Govaere, Olivier; Geerts, Anja; Van Vlierberghe, Hans

2015-01-01

Hepatocellular carcinoma (HCC) is characterized by the accumulation of unfolded proteins in the endoplasmic reticulum (ER), which activates the unfolded protein response (UPR). However, the role of ER stress in tumor initiation and progression is controversial. To determine the impact of ER stress, we applied tauroursodeoxycholic acid (TUDCA), a bile acid with chaperone properties. The effects of TUDCA were assessed using a diethylnitrosamine-induced mouse HCC model in preventive and therapeutic settings. Cell metabolic activity, proliferation and invasion were investigated in vitro. Tumor progression was assessed in the HepG2 xenograft model. Administration of TUDCA in the preventive setting reduced carcinogen-induced elevation of alanine and aspartate aminotransferase levels, apoptosis of hepatocytes and tumor burden. TUDCA also reduced eukaryotic initiation factor 2α (eIf2α) phosphorylation, C/EBP homologous protein expression and caspase-12 processing. Thus, TUDCA suppresses carcinogen-induced pro-apoptotic UPR. TUDCA alleviated hepatic inflammation by increasing NF-κB inhibitor IκBα. Furthermore, TUDCA altered the invasive phenotype and enhanced metabolic activity but not proliferation in HCC cells. TUDCA administration after tumor development did not alter orthotopic tumor or xenograft growth. Taken together, TUDCA attenuates hepatocarcinogenesis by suppressing carcinogen-induced ER stress-mediated cell death and inflammation without stimulating tumor progression. Therefore, this chemical chaperone could represent a novel chemopreventive agent. PMID:26293671

[Endoplasmic reticulum stress mediates lipopolysaccharide-induced apoptosis in rat hepatocyte].

PubMed

Ji, Ying-Lei; Yan, Jun; Wang, Yan-Sha; Liu, Yi-Chang; Gu, Zhen-Yong

2014-02-01

To investigate the role of endoplasmic reticulum stress (ERS) in lipopolysaccharide (LPS)-induced hepatocyte apoptosis. Cells of the rat hepatocyte line BRL were cultured. The hepatocytes were treated with LPS, ERS inducer thapsigargin (TG), and ERS inhibitor 4-phenylbutyric acid (4-PBA), respectively or in their different combination. The cell viability was measured by MTT assay. The cyto-nuclear morphological changes of apoptosis cells were detected by the fluorescent dye Hoechst 33258. The apoptosis rate was assessed by flow cytometry with Annexin V-FITC/PI double-staining. Expressions of GRP78 as ERS marker protein, CHOP, caspase-12 and cleaved-caspase-3 as ERS related protein were detected by Western blotting. LPS could cause a decrease in cell viability and an increase in apoptosis rate in a dose- and time-dependent manner. The expression of GRP78, CHOP, caspase-12 and cleaved-caspase-3 proteins were significantly increased with LPS treatment. TG led to a marked decrease in cell viability and an increase in apoptosis rate, which aggravated the hepatocyte injury induced by LPS; whereas 4-PBA alleviated LPS-induced apoptosis. ERS mediates LPS-induced hepatocyte injuries, indicating that ERS may play a vital role in the pathogenesis of LPS-induced hepatocyte injuries.

Stress-Induced Depression Is Alleviated by Aerobic Exercise Through Up-Regulation of 5-Hydroxytryptamine 1A Receptors in Rats.

PubMed

Kim, Tae Woon; Lim, Baek Vin; Baek, Dongjin; Ryu, Dong-Soo; Seo, Jin Hee

2015-03-01

Stress is associated with depression, which induces many psychiatric disorders. Serotonin, also known as 5-hydroxy-tryptamine (5-HT), acts as a biochemical messenger and regulator in the brain. It also mediates several important physiological functions. Depression is closely associated with an overactive bladder. In the present study, we investigated the effect of treadmill exercise on stress-induced depression while focusing on the expression of 5-HT 1A (5-H1A) receptors in the dorsal raphe. Stress was induced by applying a 0.2-mA electric foot shock to rats. Each set of electric foot shocks comprised a 6-second shock duration that was repeated 10 times with a 30-second interval. Three sets of electric foot shocks were applied each day for 7 days. For the confirmation of depressive state, a forced swimming test was performed. To visualize the expression of 5-HT and tryptophan hydroxylase (TPH), immunohistochemistry for 5-HT and TPH in the dorsal raphe was performed. Expression of 5-H1A receptors was determined by western blot analysis. A depressive state was induced by stress, and treadmill exercise alleviated the depression symptoms in the stress-induced rats. Expressions of 5-HT, TPH, and HT 1A in the dorsal raphe were reduced by the induction of stress. Treadmill exercise increased 5-HT, TPH, and HT 1A expressions in the stress-induced rats. Treadmill exercise enhanced 5-HT synthesis through the up-regulation of 5-HT1A receptors, and improved the stress-induced depression. In the present study, treadmill exercise improved depression symptoms by enhancing 5-HT1A receptor expression. The present results suggest that treadmill exercise might be helpful for the alleviation of overactive bladder and improve sexual function.

Stress-Induced Depression Is Alleviated by Aerobic Exercise Through Up-Regulation of 5-Hydroxytryptamine 1A Receptors in Rats

PubMed Central

Kim, Tae Woon; Lim, Baek Vin; Baek, Dongjin; Ryu, Dong-Soo; Seo, Jin Hee

2015-01-01

Purpose: Stress is associated with depression, which induces many psychiatric disorders. Serotonin, also known as 5-hydroxy-tryptamine (5-HT), acts as a biochemical messenger and regulator in the brain. It also mediates several important physiological functions. Depression is closely associated with an overactive bladder. In the present study, we investigated the effect of treadmill exercise on stress-induced depression while focusing on the expression of 5-HT 1A (5-H1A) receptors in the dorsal raphe. Methods: Stress was induced by applying a 0.2-mA electric foot shock to rats. Each set of electric foot shocks comprised a 6-second shock duration that was repeated 10 times with a 30-second interval. Three sets of electric foot shocks were applied each day for 7 days. For the confirmation of depressive state, a forced swimming test was performed. To visualize the expression of 5-HT and tryptophan hydroxylase (TPH), immunohistochemistry for 5-HT and TPH in the dorsal raphe was performed. Expression of 5-H1A receptors was determined by western blot analysis. Results: A depressive state was induced by stress, and treadmill exercise alleviated the depression symptoms in the stress-induced rats. Expressions of 5-HT, TPH, and HT 1A in the dorsal raphe were reduced by the induction of stress. Treadmill exercise increased 5-HT, TPH, and HT 1A expressions in the stress-induced rats. Conclusions: Treadmill exercise enhanced 5-HT synthesis through the up-regulation of 5-HT1A receptors, and improved the stress-induced depression. In the present study, treadmill exercise improved depression symptoms by enhancing 5-HT1A receptor expression. The present results suggest that treadmill exercise might be helpful for the alleviation of overactive bladder and improve sexual function. PMID:25833478

Carbon monoxide alleviates ethanol-induced oxidative damage and inflammatory stress through activating p38 MAPK pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yanyan; Gao, Chao; Shi, Yanru

2013-11-15

Stress-inducible protein heme oxygenase-1(HO-1) is well-appreciative to counteract oxidative damage and inflammatory stress involving the pathogenesis of alcoholic liver diseases (ALD). The potential role and signaling pathways of HO-1 metabolite carbon monoxide (CO), however, still remained unclear. To explore the precise mechanisms, ethanol-dosed adult male Balb/c mice (5.0 g/kg.bw.) or ethanol-incubated primary rat hepatocytes (100 mmol/L) were pretreated by tricarbonyldichlororuthenium (II) dimmer (CORM-2, 8 mg/kg for mice or 20 μmol/L for hepatocytes), as well as other pharmacological reagents. Our data showed that CO released from HO-1 induction by quercetin prevented ethanol-derived oxidative injury, which was abolished by CO scavenger hemoglobin.more » The protection was mimicked by CORM-2 with the attenuation of GSH depletion, SOD inactivation, MDA overproduction, and the leakage of AST, ALT or LDH in serum and culture medium induced by ethanol. Moreover, CORM-2 injection or incubation stimulated p38 phosphorylation and suppressed abnormal Tnfa and IL-6, accompanying the alleviation of redox imbalance induced by ethanol and aggravated by inflammatory factors. The protective role of CORM-2 was abolished by SB203580 (p38 inhibitor) but not by PD98059 (ERK inhibitor) or SP600125 (JNK inhibitor). Thus, HO-1 released CO prevented ethanol-elicited hepatic oxidative damage and inflammatory stress through activating p38 MAPK pathway, suggesting a potential therapeutic role of gaseous signal molecule on ALD induced by naturally occurring phytochemicals. - Highlights: • CO alleviated ethanol-derived liver oxidative and inflammatory stress in mice. • CO eased ethanol and inflammatory factor-induced oxidative damage in hepatocytes. • The p38 MAPK is a key signaling mechanism for the protective function of CO in ALD.« less

Cerium Improves Growth of Maize Seedlings via Alleviating Morphological Structure and Oxidative Damages of Leaf under Different Stresses.

PubMed

Hong, Fashui; Qu, Chunxiang; Wang, Ling

2017-10-18

It had been indicated that cerium (Ce) could promote maize growth involving photosynthetic improvement under potassium (K) deficiency, salt stress, and combined stress of K + deficiency and salt stress. However, whether the improved growth is related to leaf morphological structure, oxidative stress in maize leaves is not well understood. The present study showed that K + deficiency, salt stress, and their combined stress inhibited growth of maize seedlings, affecting the formation of appendages of leaf epidermal cells, and stomatal opening, which may be due to increases in H 2 O 2 and malondialdehyde levels, and reductions in Ca 2+ content, ratios of glutathione/oxidized glutathione, ascorbic acid/dehydroascorbic acid, and the activities of superoxide dismutase, catalase, ascorbic acid peroxidase, guaiacol peroxidase, and glutathione reductase in leaves under different stresses. The adverse effects caused by combined stress were higher than those of single stress. Furthermore, our findings demonstrated that adding Ce 3+ could significantly promote seedling growth, and alleviate morphological and structural damage of leaf, decrease oxidative stress and increase antioxidative capacity in maize leaves caused by different stresses.

Flurbiprofen ameliorated obesity by attenuating leptin resistance induced by endoplasmic reticulum stress

PubMed Central

Hosoi, Toru; Yamaguchi, Rie; Noji, Kikuko; Matsuo, Suguru; Baba, Sachiko; Toyoda, Keisuke; Suezawa, Takahiro; Kayano, Takaaki; Tanaka, Shinpei; Ozawa, Koichiro

2014-01-01

Endoplasmic reticulum (ER) stress, caused by the accumulation of unfolded proteins, is involved in the development of obesity. We demonstrated that flurbiprofen, a nonsteroidal anti-inflammatory drug (NSAID), exhibited chaperone activity, which reduced protein aggregation and alleviated ER stress-induced leptin resistance, characterized by insensitivity to the actions of the anti-obesity hormone leptin. This result was further supported by flurbiprofen attenuating high-fat diet-induced obesity in mice. The other NSAIDs tested did not exhibit such effects, which suggested that this anti-obesity action is mediated independent of NSAIDs. Using ferriteglycidyl methacrylate beads, we identified aldehyde dehydrogenase as the target of flurbiprofen, but not of the other NSAIDs. These results suggest that flurbiprofen may have unique pharmacological properties that reduce the accumulation of unfolded proteins and may represent a new class of drug for the fundamental treatment of obesity. Subject Categories Metabolism; Pharmacology & Drug Discovery PMID:24421337

ER stress signaling and neurodegeneration: At the intersection between Alzheimer's disease and Prion-related disorders.

PubMed

Torres, Mauricio; Matamala, José Manuel; Duran-Aniotz, Claudia; Cornejo, Victor Hugo; Foley, Andrew; Hetz, Claudio

2015-09-02

Alzheimer's and Prion diseases are two neurodegenerative conditions sharing different pathophysiological characteristics. Disease symptoms are associated with the abnormal accumulation of protein aggregates, which are generated by the misfolding and oligomerization of specific proteins. Recent functional studies uncovered a key role of endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) in the occurrence of synaptic dysfunction and neurodegeneration in Prion-related disorders and Alzheimer's disease. Here we review common pathological features of both diseases, emphasizing the link between amyloid formation, its pathogenesis and alterations in ER proteostasis. The potential benefits of targeting the UPR as a therapeutic strategy is also discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

Curcumin attenuates glutamate neurotoxicity in the hippocampus by suppression of ER stress-associated TXNIP/NLRP3 inflammasome activation in a manner dependent on AMPK

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Ying; Li, Jia; Li, Shanshan

2015-07-01

Curcumin is a natural polyphenolic compound in Curcuma longa with beneficial effects on neuronal protection. This study aims to investigate the action of curcumin in the hippocampus subjected to glutamate neurotoxicity. Glutamate stimulation induced reactive oxygen species (ROS), endoplasmic reticulum stress (ER stress) and TXNIP/NLRP3 inflammasome activation, leading to damage in the hippocampus. Curcumin treatment in the hippocampus or SH-SY5Y cells inhibited IRE1α and PERK phosphorylation with suppression of intracellular ROS production. Curcumin increased AMPK activity and knockdown of AMPKα with specific siRNA abrogated its inhibitory effects on IRE1α and PERK phosphorylation, indicating that AMPK activity was essential for themore » suppression of ER stress. As a result, curcumin reduced TXNIP expression and inhibited NLRP3 inflammasome activation by downregulation of NLRP3 and cleaved caspase-1 induction, and thus reduced IL-1β secretion. Specific fluorescent probe and flow cytometry analysis showed that curcumin prevented mitochondrial malfunction and protected cell survival from glutamate neurotoxicity. Moreover, oral administration of curcumin reduced brain infarct volume and attenuated neuronal damage in rats subjected to middle cerebral artery occlusion. Immunohistochemistry showed that curcumin inhibited p-IRE1α, p-PERK and NLRP3 expression in hippocampus CA1 region. Together, these results showed that curcumin attenuated glutamate neurotoxicity by inhibiting ER stress-associated TXNIP/NLRP3 inflammasome activation via the regulation of AMPK, and thereby protected the hippocampus from ischemic insult. - Highlights: • Curcumin attenuates glutamate neurotoxicity in the hippocampus. • Curcumin suppresses ER stress in glutamate-induced hippocampus slices. • Curcumin inhibits TXNIP/NLRP3 inflammasome activation. • Regulation of AMPK by curcumin contributes to suppressing ER stress.« less

The high-fat diet induces myocardial fibrosis in the metabolically healthy obese minipigs-The role of ER stress and oxidative stress.

PubMed

Li, Sin-Jin; Liu, Chia-Hsin; Chu, Hsien-Pin; Mersmann, Harry J; Ding, Shih-Torng; Chu, Chun-Han; Wang, Chia-Yu; Chen, Ching-Yi

2017-06-01

The cellular mechanisms of obesity-induced cardiomyopathy are multiple and not completely elucidated. The objective of this study was to differentiate two obesity-associated cardiomyopathy miniature pig models: one with the metabolic syndrome (MetS), and one with a metabolically healthy obesity (MHO). The cellular responses during the development of obesity-induced cardiomyopathy were investigated. Five-month-old Lee-Sung (MetS) and Lanyu (MHO) minipigs were made obese by feeding a high-fat diet (HFD) for 6 months. Obese pigs exhibited a greater heart weight than control pigs. Interstitial and perivascular fibrosis developed in the myocardium of obese pigs. The HFD induced cardiac lipid accumulation and oxidative stress and also decreased the antioxidant defense in MetS pigs. This diet activated oxidative stress without changing cardiac antioxidant defense and lipid content in MHO pigs. The HFD upregulated the expression of Grp94, CHOP, caspase 12, p62, and LC3II, and increased the ratio of LC3II to LC3I in the left ventricle (LV) of MetS pigs. Compared to obese MetS pigs, less Grp94 and elevated CHOP expression was found in the obese MHO heart. The HFD did not change the ratio of LC3II to LC3I and p62 expression in obese MHO pigs. The obese MetS pigs had an extensive and greater inflammatory response in the plasma than the obese MHO pigs, which had a lesser and milder inflammation. Oxidative stress and ER stress were involved in the progression of MHO-related cardiomyopathy. Inflammation, autophagy, ER stress, oxidative stress, and lipotoxicity participated in the pathological mechanism of MetS-related cardiomyopathy. Copyright © 2016 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Salubrinal protects human skin fibroblasts against UVB-induced cell death by blocking endoplasmic reticulum (ER) stress and regulating calcium homeostasis.

PubMed

Ji, Chao; Yang, Bo; Huang, Shu-Ying; Huang, Jin-Wen; Cheng, Bo

2017-12-02

The role of UVB in skin photo damages has been widely reported. Overexposure to UVB will induce severe DNA damages in epidermal cells and cause most cytotoxic symptoms. In the present study, we tested the potential activity of salubrinal, a selective inhibitor of Eukaryotic Initiation Factor 2 (eIF2) -alpha phosphatase, against UV-induced skin cell damages. We first exposed human fibroblasts to UVB radiation and evaluated the cytosolic Ca 2+ level as well as the induction of ER stress. We found that UVB radiation induced the depletion of ER Ca 2+ and increased the expression of ER stress marker including phosphorylated PERK, CHOP, and phosphorylated IRE1α. We then determined the effects of salubrinal in skin cell death induced by UVB radiation. We observed that cells pre-treated with salubrinal had a higher survival rate compared to cells treated with UVB alone. Pre-treatment with salubrinal successfully re-established the ER function and Ca 2+ homeostasis. Our results suggest that salubrinal can be a potential therapeutic agents used in preventing photoaging and photo damages. Copyright © 2017 Elsevier Inc. All rights reserved.

ER stress and Parkinson's disease: Pathological inputs that converge into the secretory pathway.

PubMed

Mercado, Gabriela; Castillo, Valentina; Soto, Paulina; Sidhu, Anita

2016-10-01

The major clinical feature of Parkinson's disease (PD) is impairment in motor control as a result of extensive dopaminergic neuron loss in the substantia nigra pars compacta. The central pathological hallmark of PD is the formation of neuronal cytoplasmic inclusions of insoluble proteins called Lewy bodies, of which fibrillar aggregates of misfolded αSynuclein are the major components. Despite intense research on the pathogenic mechanism that trigger neuronal loss and disease progression, the neurogenesis of PD remains unknown. However, studies on genetics of PD have identified specific genes and proteins linked to this disease. Genetic mutations linked with different forms of familial PD have unveiled a closer relationship between pathology and impairments at different points in the secretory pathway. Accumulation of misfolded/unfolded proteins in the endoplasmic reticulum and disruptions in protein clearance mechanisms result in activation of an adaptive stress pathway known as the unfolded protein response (UPR). UPR signaling is mediated by three stress sensors that induce independent and convergent signaling branches that help to maintain homeostasis, or eventually trigger cell death under chronic stress conditions. Signs of ER stress are observed in post-mortem tissue from sporadic human PD cases and in most animal models of the disease, implicating all three branches of this cellular response. However, the exact contribution of the UPR in the progression of PD or in dopaminergic neuron survival is not yet well understood. A large number of studies reveal a clear activation of the UPR in toxicological models resembling sporadic PD, where ATF6, XBP1 and CHOP have a functional role in controlling dopaminergic neuron survival in neurotoxin-based models of PD in vivo. Also pharmacological and gene therapy approaches aimed to target different points of this pathway have revealed an important functional role in PD pathogenesis. This article is part of a Special

GSK3β and VDAC Involvement in ER Stress and Apoptosis Modulation during Orthotopic Liver Transplantation

PubMed Central

Zaouali, Mohamed Amine; Panisello, Arnau; Lopez, Alexandre; Castro, Carlos; Folch, Emma; Carbonell, Teresa; Rolo, Anabela; Palmeira, Carlos Marques; Garcia-Gil, Agustin; Adam, René; Roselló-Catafau, Joan

2017-01-01

We investigated the involvement of glycogen synthase kinase-3β (GSK3β) and the voltage-dependent anion channel (VDAC) in livers subjected to cold ischemia–reperfusion injury (I/R) associated with orthotopic liver transplantation (OLT). Rat livers were preserved in University of Wisconsin (UW) and Institute Georges Lopez (IGL-1) solution, the latter enriched or not with trimetazidine, and then subjected to OLT. Transaminase (ALT) and HMGB1 protein levels, glutamate dehydrogenase (GLDH), and oxidative stress (MDA) were measured. The AKT protein kinase and its direct substrates, GSK3β and VDAC, as well as caspases 3, 9, and cytochrome C and reticulum endoplasmic stress-related proteins (GRP78, pPERK, ATF4, and CHOP), were determined by Western blot. IGL-1+TMZ significantly reduced liver injury. We also observed a significant phosphorylation of AKT, which in turn induced the phosphorylation and inhibition of GSK3β. In addition, TMZ protected the mitochondria since, in comparison with IGL-1 alone, we found reductions in VDAC phosphorylation, apoptosis, and GLDH release. All these results were correlated with decreased ER stress. Addition of TMZ to IGL-1 solution increased the tolerance of the liver graft to I/R injury through inhibition of GSK3β and VDAC, contributing to ER stress reduction and cell death prevention. PMID:28282906

Nonautophagic cytoplasmic vacuolation death induction in human PC-3M prostate cancer by curcumin through reactive oxygen species -mediated endoplasmic reticulum stress

PubMed Central

Lee, Wei-Jiunn; Chien, Ming-Hsien; Chow, Jyh-Ming; Chang, Junn-Liang; Wen, Yu-Ching; Lin, Yung-Wei; Cheng, Chao-Wen; Lai, Gi-Ming; Hsiao, Michael; Lee, Liang-Ming

2015-01-01

The antiapoptotic and antiautophagic abilities of cancer cells constitute a major challenge for anticancer drug treatment. Strategies for triggering nonapoptotic or nonautophagic cell death may improve therapeutic efficacy against cancer. Curcumin has been reported to exhibit cancer chemopreventive properties. Herein, we report that curcumin induced apoptosis in LNCaP, DU145, and PC-3 cells but triggered extensive cytoplasmic vacuolation in PC-3M cells. Electron microscopic images showed that the vacuoles lacked intracellular organelles and were derived from the endoplasmic reticulum (ER). Moreover, curcumin-induced vacuolation was not reversed by an apoptosis- or autophagy-related inhibitor, suggesting that vacuolation-mediated cell death differs from classical apoptotic and autophagic cell death. Mechanistic investigations revealed that curcumin treatment upregulated the ER stress markers CHOP and Bip/GRP78 and the autophagic marker LC3-II. In addition, curcumin induced ER stress by triggering ROS generation, which was supported by the finding that treating cells with the antioxidant NAC alleviated curcumin-mediated ER stress and vacuolation-mediated death. An in vivo PC-3M orthotopic prostate cancer model revealed that curcumin reduced tumor growth by inducing ROS production followed by vacuolation-mediated cell death. Overall, our results indicated that curcumin acts as an inducer of ROS production, which leads to nonapoptotic and nonautophagic cell death via increased ER stress. PMID:26013662

Involvement of ER stress and activation of apoptotic pathways in fisetin induced cytotoxicity in human melanoma

PubMed Central

Chamcheu, Jean Christopher; Haidar, Omar; Mukhtar, Hasan

2014-01-01

The prognosis of malignant melanoma remains poor in spite of recent advances in therapeutic strategies for the deadly disease. Fisetin, a dietary flavonoid is currently being investigated for its growth inhibitory properties in various cancer models. We previously showed that fisetin inhibited melanoma growth in vitro and in vivo. Here, we evaluated the molecular basis of fisetin induced cytoxicity in metastatic human melanoma cells. Fisetin treatment induced endoplasmic reticulum (ER) stress in highly aggressive A375 and 451Lu human melanoma cells, as revealed by up- regulation of ER stress markers including IRE1α, XBP1s, ATF4 and GRP78. Time course analysis indicated that the ER stress was associated with activation of the extrinsic and intrinsic apoptotic pathways. Fisetin treated 2-D melanoma cultures displayed autophagic response concomitant with induction of apoptosis. Prolonged treatment (16 days) with fisetin in a 3-D reconstituted melanoma model resulted in inhibition of melanoma progression with significant apoptosis, as evidenced by increased staining of cleaved Caspase-3 in the treated constructs. However, no difference in the expression of autophagic marker LC-3 was noted between treated and control groups. Fisetin treatment to 2-D melanoma cultures resulted in phosphorylation and activation of the multifunctional AMPK-activated protein kinase (AMPK) involved in the regulation of diverse cellular processes, including autophagy and apoptosis. Silencing of AMPK failed to prevent cell death indicating that fisetin induced cytotoxicity is mediated through both AMPK-dependent and -independent mechanisms. Taken together, our studies confirm apoptosis as the primary mechanism through which fisetin inhibits melanoma cell growth and that activation of both extrinsic and intrinsic pathways contributes to fisetin induced cytotoxicity. PMID:25016296

Involvement of ER stress and activation of apoptotic pathways in fisetin induced cytotoxicity in human melanoma.

PubMed

Syed, Deeba N; Lall, Rahul K; Chamcheu, Jean Christopher; Haidar, Omar; Mukhtar, Hasan

2014-12-01

The prognosis of malignant melanoma remains poor in spite of recent advances in therapeutic strategies for the deadly disease. Fisetin, a dietary flavonoid is currently being investigated for its growth inhibitory properties in various cancer models. We previously showed that fisetin inhibited melanoma growth in vitro and in vivo. Here, we evaluated the molecular basis of fisetin induced cytotoxicity in metastatic human melanoma cells. Fisetin treatment induced endoplasmic reticulum (ER) stress in highly aggressive A375 and 451Lu human melanoma cells, as revealed by up-regulation of ER stress markers including IRE1α, XBP1s, ATF4 and GRP78. Time course analysis indicated that the ER stress was associated with activation of the extrinsic and intrinsic apoptotic pathways. Fisetin treated 2-D melanoma cultures displayed autophagic response concomitant with induction of apoptosis. Prolonged treatment (16days) with fisetin in a 3-D reconstituted melanoma model resulted in inhibition of melanoma progression with significant apoptosis, as evidenced by increased staining of cleaved Caspase-3 in the treated constructs. However, no difference in the expression of autophagic marker LC-3 was noted between treated and control groups. Fisetin treatment to 2-D melanoma cultures resulted in phosphorylation and activation of the multifunctional AMP-activated protein kinase (AMPK) involved in the regulation of diverse cellular processes, including autophagy and apoptosis. Silencing of AMPK failed to prevent cell death indicating that fisetin induced cytotoxicity is mediated through both AMPK-dependent and -independent mechanisms. Taken together, our studies confirm apoptosis as the primary mechanism through which fisetin inhibits melanoma cell growth and that activation of both extrinsic and intrinsic pathways contributes to fisetin induced cytotoxicity.

Chronic Kidney Disease Exacerbates Myocardial Ischemia Reperfusion Injury: Role of Endoplasmic Reticulum Stress-Mediated Apoptosis.

PubMed

Guo, Junjie; Zhu, Jianbing; Ma, Leilei; Shi, Hongtao; Hu, Jiachang; Zhang, Shuning; Hou, Lei; Xu, Fengqiang; An, Yi; Yu, Haichu; Ge, Junbo

2018-06-01

Chronic kidney disease (CKD) is known to exacerbate myocardial ischemia reperfusion (IR) injury. However, the underlying mechanisms are still not well understood. Despite various strategies for cardioprotection, limited studies have been focused on the prevention of CKD-induced myocardial susceptibility to IR injury. Here, we hypothesized that excessive endoplasmic reticulum (ER) stress-mediated apoptosis involved in myocardial IR injury in CKD mice and pretreatment with chemical ER chaperone rendered the heart resistant to myocardial IR injury in the setting of CKD. CKD was induced by 5/6 subtotal nephrectomy (SN) in mice, whereas sham-operated mice served as control (Sham). CKD significantly aggravated the cardiac injury after IR in SN group than Sham group as reflected by more severe cardiac dysfunction, increased myocardial infarct size and the ratio of myocardial apoptosis. The expression of ER stress-mediated apoptotic proteins (Bcl-2 associated X protein (Bax), glucose-regulated protein 78 (GRP78), CCAAT/enhancer-binding protein homologous protein (CHOP), caspase-12) was markedly upregulated after IR injury in SN group than Sham group, whereas the expression of anti-apoptotic protein, Bcl-2, was obviously downregulated. In addition, the chemical ER chaperone sodium 4-phenylbutyrate (4PBA) pretreatment ameliorated cardiac dysfunction and lessened the infarct size and myocardial apoptosis after IR injury in mice with CKD. Taken together, these findings demonstrated that excessive activation of ER stress-mediated apoptosis pathway involved in the CKD-induced myocardial susceptibility to IR injury, and chemical ER chaperone 4PBA alleviated myocardial IR injury in mice with CKD.

Fenofibrate Does Not Affect Burn-Induced Hepatic Endoplasmic Reticulum Stress

PubMed Central

Hiyama, Yaeko; Marshall, Alexandra H.; Kraft, Robert; Arno, Anna; Jeschke, Marc G.

2013-01-01

Background Burn injury causes major metabolic derangements such as hypermetabolism, hyperlipidemia, and insulin resistance and is associated with liver damage, hepatomegaly, and hepatic endoplasmic reticulum (ER) stress. Although the physiological consequences of such derangements have been delineated, the underlying molecular mechanisms remain unknown. Previously, it was shown that fenofibrate improves patient outcome by attenuating post-burn stress responses. Methods Fenofibrate, a peroxisome proliferator-activated receptor (PPAR)-α agonist, regulates liver lipid metabolism and has been used to treat hypertriglyceridemia and hypercholesterolemia for many years. The aim of the present study is to determine the effects of fenofibrate on burn-induced hepatic morphologic and metabolic changes. We randomized rats to sham, burn injury, and burn injury plus fenofibrate. Animals were sacrificed and livers were assessed at 24 or 48 hours post-burn. Results Burn injury decreased albumin and increased alanine transaminase (p = 0.1 vs. sham), indicating liver injury. Fenofibrate administration did not restore albumin or decrease alanine transaminase. In addition, ER stress was significantly increased after burn injury both with and without fenofibrate (p < 0.05 vs. sham). Burn injury increased fatty acid metabolism gene expression (p < 0.05 vs. sham), downstream of PPARα. Fenofibrate treatment increased fatty acid metabolism further, which reduced post-burn hepatic steatosis (burn vs. sham p < 0.05, burn+fenofibrate vs. sham not significant). Conclusions Fenofibrate did not alleviate thermal injury induced hepatic ER stress and dysfunction but reduced hepatic steatosis by modulating hepatic genes related to fat metabolism. PMID:23866789

Resveratrol triggers ER stress-mediated apoptosis by disrupting N-linked glycosylation of proteins in ovarian cancer cells.

PubMed

Gwak, HyeRan; Kim, Soochi; Dhanasekaran, Danny N; Song, Yong Sang

2016-02-28

Malignant tumors have a high glucose demand and alter cellular metabolism to survive. Herein, focusing on the utility of glucose metabolism as a therapeutic target, we found that resveratrol induced endoplasmic reticulum (ER) stress-mediated apoptosis by interrupting protein glycosylation in a cancer-specific manner. Our results indicated that resveratrol suppressed the hexosamine biosynthetic pathway and interrupted protein glycosylation through GSK3β activation. Application of either biochemical intermediates of the hexosamine pathway or small molecular inhibitors of GSK3β reversed the effects of resveratrol on the disruption of protein glycosylation. Additionally, an ER UDPase, ectonucleoside triphosphate diphosphohydrolase 5 (ENTPD5), modulated protein glycosylation by Akt attenuation in response to resveratrol. By inhibition or overexpression of Akt functions, we confirmed that the glycosylation activities were dependent on ENTPD5 expression and regulated by the action of Akt in ovarian cancer cells. Resveratrol-mediated disruption of protein glycosylation induced cellular apoptosis as indicated by the up-regulation of GADD153, followed by the activation of ER-stress sensors (PERK and ATF6α). Thus, our results provide novel insight into cancer cell metabolism and protein glycosylation as a therapeutic target for cancers. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

A molecular web: endoplasmic reticulum stress, inflammation, and oxidative stress.

PubMed

Chaudhari, Namrata; Talwar, Priti; Parimisetty, Avinash; Lefebvre d'Hellencourt, Christian; Ravanan, Palaniyandi

2014-01-01

Execution of fundamental cellular functions demands regulated protein folding homeostasis. Endoplasmic reticulum (ER) is an active organelle existing to implement this function by folding and modifying secretory and membrane proteins. Loss of protein folding homeostasis is central to various diseases and budding evidences suggest ER stress as being a major contributor in the development or pathology of a diseased state besides other cellular stresses. The trigger for diseases may be diverse but, inflammation and/or ER stress may be basic mechanisms increasing the severity or complicating the condition of the disease. Chronic ER stress and activation of the unfolded-protein response (UPR) through endogenous or exogenous insults may result in impaired calcium and redox homeostasis, oxidative stress via protein overload thereby also influencing vital mitochondrial functions. Calcium released from the ER augments the production of mitochondrial Reactive Oxygen Species (ROS). Toxic accumulation of ROS within ER and mitochondria disturbs fundamental organelle functions. Sustained ER stress is known to potentially elicit inflammatory responses via UPR pathways. Additionally, ROS generated through inflammation or mitochondrial dysfunction could accelerate ER malfunction. Dysfunctional UPR pathways have been associated with a wide range of diseases including several neurodegenerative diseases, stroke, metabolic disorders, cancer, inflammatory disease, diabetes mellitus, cardiovascular disease, and others. In this review, we have discussed the UPR signaling pathways, and networking between ER stress-induced inflammatory pathways, oxidative stress, and mitochondrial signaling events, which further induce or exacerbate ER stress.

A Molecular Web: Endoplasmic Reticulum Stress, Inflammation, and Oxidative Stress

PubMed Central

Chaudhari, Namrata; Talwar, Priti; Parimisetty, Avinash; Lefebvre d’Hellencourt, Christian; Ravanan, Palaniyandi

2014-01-01

Execution of fundamental cellular functions demands regulated protein folding homeostasis. Endoplasmic reticulum (ER) is an active organelle existing to implement this function by folding and modifying secretory and membrane proteins. Loss of protein folding homeostasis is central to various diseases and budding evidences suggest ER stress as being a major contributor in the development or pathology of a diseased state besides other cellular stresses. The trigger for diseases may be diverse but, inflammation and/or ER stress may be basic mechanisms increasing the severity or complicating the condition of the disease. Chronic ER stress and activation of the unfolded-protein response (UPR) through endogenous or exogenous insults may result in impaired calcium and redox homeostasis, oxidative stress via protein overload thereby also influencing vital mitochondrial functions. Calcium released from the ER augments the production of mitochondrial Reactive Oxygen Species (ROS). Toxic accumulation of ROS within ER and mitochondria disturbs fundamental organelle functions. Sustained ER stress is known to potentially elicit inflammatory responses via UPR pathways. Additionally, ROS generated through inflammation or mitochondrial dysfunction could accelerate ER malfunction. Dysfunctional UPR pathways have been associated with a wide range of diseases including several neurodegenerative diseases, stroke, metabolic disorders, cancer, inflammatory disease, diabetes mellitus, cardiovascular disease, and others. In this review, we have discussed the UPR signaling pathways, and networking between ER stress-induced inflammatory pathways, oxidative stress, and mitochondrial signaling events, which further induce or exacerbate ER stress. PMID:25120434

Geraniol alleviates diabetic cardiac complications: Effect on cardiac ischemia and oxidative stress.

PubMed

El-Bassossy, Hany M; Ghaleb, Hanna; Elberry, Ahmed A; Balamash, Khadijah S; Ghareib, Salah A; Azhar, Ahmad; Banjar, Zainy

2017-04-01

The present study was planned to assess the possible protective effect of geraniol on cardiovascular complications in an animal model with diabetes. Diabetes was induced in rats by a single streptozotocin injection. In the treated group, geraniol (150mgkg -1 day -1 ) was administered orally starting from the 15th day after induction of diabetes, and ending after 7 weeks; diabetic control rats were given vehicle for the same period. At the end of the study, cardiac contractility was assessed by using a Millar microtip catheter in anesthetised rats, and cardiac conductivity determined by a surface ECG. Serum levels of glucose, cholesterol, triglyceride and adiponectin as well as urine 8-isoprostane were determined. In addition, cardiac superoxide dismutase (SOD) and catalase activity were measured. Geraniol administration significantly alleviated the attenuated cardiac systolic function associated with diabetes as indicated by inhibiting the decrease in the rate of rise (dP/dt max ) in ventricular pressure and the increase in systolic duration observed in diabetic rats. In addition, geraniol alleviated impaired diastolic function as shown by inhibiting the decrease in the rate of fall (dP/dt min ) in ventricular pressure and increased isovolumic relaxation constant (Tau) observed in diabetic rats. ECG recordings showed that geraniol prevented any increase in QTc and T-peak-T-end intervals, and markers of LV ischemia and arrhythmogenesis, seen in diabetic animals. Geraniol suppressed the exaggerated oxidative stress as evidenced by preventing the increase in 8-isoprotane. In diabetic heart tissue, geraniol prevented the inhibition in catalase activity but did not affect the heart SOD. Geraniol partially reduced hyperglycemia, prevented the hypercholesterolemia, but did not affect the serum level of adiponectin in diabetic animals. Results obtained in this study suggest that geraniol provides a potent protective effect against cardiac dysfunction induced by diabetes

Endoplasmic reticulum stress is increased after spontaneous labor in human fetal membranes and myometrium where it regulates the expression of prolabor mediators.

PubMed

Liong, Stella; Lappas, Martha

2014-09-01

Increasing evidence indicates that endoplasmic reticulum (ER) stress is involved in various diseases. In nongestational tissues, several markers of the unfolded protein response (UPR) have been shown to regulate the inflammatory response. Thus, the aim of this study was to determine the effect of human labor on markers of ER stress in fetal membranes and myometrium. In addition, the effect of ER stress inhibition on the expression and secretion of proinflammatory and prolabor mediators was also assessed. The markers of ER stress, GRP78, IRE1, and spliced XBP1 (XBP1s), were significantly increased in fetal membranes and myometrium after term and preterm labor compared to nonlaboring samples. Given that inflammation is considered to be one of the leading causes of spontaneous preterm birth, here we used bacterial endotoxin lipopolysaccharide (LPS) as a model for infection-induced preterm birth. In term nonlabored fetal membranes and myometrium, LPS induced UPR activation as evidenced by a significant increase in the expression of GRP78, IRE1, and XBP1s in fetal membranes and myometrium. The use of the chemical chaperones 4-phenylbutyric acid (4-PBA) and tauroursodeoxycholic acid (TUDCA) alleviated ER stress induced by LPS. 4-PBA and TUDCA also ameliorated the increase in LPS-induced prolabor mediators. Our data suggest that the UPR may regulate the inflammatory responses associated with labor or infection in fetal membranes and myometrium of pregnant term and preterm women. Thus, the use of ER stress inhibitors, in particular 4-PBA or TUDCA, may be a potential therapeutic strategy for the prevention of infection-mediated spontaneous preterm birth. © 2014 by the Society for the Study of Reproduction, Inc.

Sulfur Dioxide Enhances Endogenous Hydrogen Sulfide Accumulation and Alleviates Oxidative Stress Induced by Aluminum Stress in Germinating Wheat Seeds

PubMed Central

Zhu, Dong-Bo; Hu, Kang-Di; Guo, Xi-Kai; Liu, Yong; Hu, Lan-Ying; Li, Yan-Hong; Wang, Song-Hua; Zhang, Hua

2015-01-01

Aluminum ions are especially toxic to plants in acidic soils. Here we present evidences that SO2 protects germinating wheat grains against aluminum stress. SO2 donor (NaHSO3/Na2SO3) pretreatment at 1.2 mM reduced the accumulation of superoxide anion, hydrogen peroxide, and malondialdehyde, enhanced the activities of guaiacol peroxidase, catalase, and ascorbate peroxidase, and decreased the activity of lipoxygenase in germinating wheat grains exposed to Al stress. We also observed higher accumulation of hydrogen sulfide (H2S) in SO2-pretreated grain, suggesting the tight relation between sulfite and sulfide. Wheat grains geminated in water for 36 h were pretreated with or without 1 mM SO2 donor for 12 h prior to exposure to Al stress for 48 h and the ameliorating effects of SO2 on wheat radicles were studied. SO2 donor pretreatment reduced the content of reactive oxygen species, protected membrane integrity, and reduced Al accumulation in wheat radicles. Gene expression analysis showed that SO2 donor pretreatment decreased the expression of Al-responsive genes TaWali1, TaWali2, TaWali3, TaWali5, TaWali6, and TaALMT1 in radicles exposed to Al stress. These results suggested that SO2 could increase endogenous H2S accumulation and the antioxidant capability and decrease endogenous Al content in wheat grains to alleviate Al stress. PMID:26078810

Exogenously applied spermidine alleviates photosynthetic inhibition under drought stress in maize (Zea mays L.) seedlings associated with changes in endogenous polyamines and phytohormones.

PubMed

Li, Lijie; Gu, Wanrong; Li, Jing; Li, Congfeng; Xie, Tenglong; Qu, Danyang; Meng, Yao; Li, Caifeng; Wei, Shi

2018-05-15

Drought stress (DS) is a major environmental factor limiting plant growth and crop productivity worldwide. It has been established that exogenous spermidine (Spd) stimulates plant tolerance to DS. The effects of exogenous Spd on plant growth, photosynthetic performance, and chloroplast ultrastructure as well as changes in endogenous polyamines (PAs) and phytohormones were investigate in DS-resistant (Xianyu 335) and DS-sensitive (Fenghe 1) maize seedlings under well-watered and DS treatments. Exogenous Spd alleviated the stress-induced reduction in growth, photosynthetic pigment content, photosynthesis rate (P n ) and photochemical quenching (q P ) parameters, including the maximum photochemistry efficiency of photosystem II (PSII) (F v /F m ), PSII operating efficiency (ФPSII), and qP coefficient. Exogenous Spd further enhanced stress-induced elevation in non-photochemical quenching (NPQ) and the de-epoxidation state of the xanthophyll cycle (DEPS). Microscopic analysis revealed that seedlings displayed a more ordered arrangement of chloroplast ultrastructure upon Spd application during DS. Exogenous Spd increased the endogenous PA concentrations in the stressed plants. Additionally, exogenous Spd increased indoleacetic acid (IAA), zeatin riboside (ZR) and gibberellin A 3 (GA 3 ) and decreased salicylic acid (SA) and jasmonate (JA) concentrations under DS. These results indicate that exogenous Spd can alleviate the growth inhibition and damage to the structure and function of the photosynthetic apparatus caused by DS and that this alleviation may be associated with changes in endogenous PAs and phytohormones. This study contributes to advances in the knowledge of Spd-induced drought tolerance. Copyright © 2018. Published by Elsevier Masson SAS.

[Alleviation effects of melatonin and Ca2+ on melon seedlings under salt stress].

PubMed

Gao, Qing Hai; Guo, Yuan Yuan; Wu, Yan; Jia, Shuang Shuang

2017-06-18

To assess the role of exogenous melatonin (MT) and Ca 2+ in melon under salt stress, the content of mineral elements (Cl - , Na + , K + , Mg 2+ , Ca 2+ ), the values of Na + /K + , Na + /Ca 2+ , Na + /Mg 2+ , the activity of H + -ATP, the accumulation of osmotic substances and membrane lipid peroxidation in melon under salt stress were investigated in the environmental conditions (day/night 25/18 ℃) controlled by artificial climate chamber. The results showed that salt stress significantly inhibited growth of the melon seedlings with the increased contents of Cl - and Na + in roots and lea-ves, and the decreased contents of K + , Mg 2+ and Ca 2+ , compared with the control. Under salt stress, exogenous application of MT or Ca 2+ remarkably reduced the contents of Cl - and Na + in roots and leaves, increased the contents of K + , Mg 2+ and Ca 2+ , and decreased values of Na + /K + , Na + /Ca 2+ and Na + /Mg 2+ . Additionally, exogenous melatonin or Ca 2+ increased H + -ATP activity and osmotic adjustments, and further alleviated cell membrane injuries imposed by salt stress, displaying lower MDA content and relative conductivity. Collectively, this work suggested that single or combined applications of exogenous MT and Ca 2+ effectively reduced the content of Cl - and Na + , improved ion balance by enhancing H + -ATP activity, and increased the content of osmotic adjustment substances for ameliorating membrane lipid peroxidation, thereby enhancing plant adaptation to salt stress, especially combined applications of exogenous MT and Ca 2+ . Our results further showed that the combined application of exogenous MT and Ca 2+ resulted in a synergistic effect on increasing salt tolerance in melon seedlings.

The ER stress sensor PERK luminal domain functions as a molecular chaperone to interact with misfolded proteins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Peng; Li, Jingzhi; Sha, Bingdong

2016-11-29

PERK is one of the major sensor proteins which can detect the protein-folding imbalance generated by endoplasmic reticulum (ER) stress. It remains unclear how the sensor protein PERK is activated by ER stress. It has been demonstrated that the PERK luminal domain can recognize and selectively interact with misfolded proteins but not native proteins. Moreover, the PERK luminal domain may function as a molecular chaperone to directly bind to and suppress the aggregation of a number of misfolded model proteins. The data strongly support the hypothesis that the PERK luminal domain can interact directly with misfolded proteins to induce ERmore » stress signaling. To illustrate the mechanism by which the PERK luminal domain interacts with misfolded proteins, the crystal structure of the human PERK luminal domain was determined to 3.2 Å resolution. Two dimers of the PERK luminal domain constitute a tetramer in the asymmetric unit. Superimposition of the PERK luminal domain molecules indicated that the β-sandwich domain could adopt multiple conformations. It is hypothesized that the PERK luminal domain may utilize its flexible β-sandwich domain to recognize and interact with a broad range of misfolded proteins.« less

Rootstock alleviates PEG-induced water stress in grafted pepper seedlings: physiological responses.

PubMed

Penella, Consuelo; Nebauer, Sergio G; Bautista, Alberto San; López-Galarza, Salvador; Calatayud, Ángeles

2014-06-15

nitrate reductase activity in the roots was observed, mainly in plants grafted onto the sensitive rootstocks, as well as the ungrafted plants, and this was associated with the lessened flux to the leaves. This study suggests that PEG-induced water stress can be partially alleviated by using tolerant accessions as rootstocks. Copyright © 2014 Elsevier GmbH. All rights reserved.

Nitrogen availability regulates proline and ethylene production and alleviates salinity stress in mustard (Brassica juncea).

PubMed

Iqbal, Noushina; Umar, Shahid; Khan, Nafees A

2015-04-15

Proline content and ethylene production have been shown to be involved in salt tolerance mechanisms in plants. To assess the role of nitrogen (N) in the protection of photosynthesis under salt stress, the effect of N (0, 5, 10, 20 mM) on proline and ethylene was studied in mustard (Brassica juncea). Sufficient N (10 mM) optimized proline production under non-saline conditions through an increase in proline-metabolizing enzymes, leading to osmotic balance and protection of photosynthesis through optimal ethylene production. Excess N (20 mM), in the absence of salt stress, inhibited photosynthesis and caused higher ethylene evolution but lower proline production compared to sufficient N. In contrast, under salt stress with an increased demand for N, excess N optimized ethylene production, which regulates the proline content resulting in recovered photosynthesis. The effect of excess N on photosynthesis under salt stress was further substantiated by the application of the ethylene biosynthesis inhibitor, 1-aminoethoxy vinylglycine (AVG), which inhibited proline production and photosynthesis. Without salt stress, AVG promoted photosynthesis in plants receiving excess N by inhibiting stress ethylene production. The results suggest that a regulatory interaction exists between ethylene, proline and N for salt tolerance. Nitrogen differentially regulates proline production and ethylene formation to alleviate the adverse effect of salinity on photosynthesis in mustard. Copyright © 2015 Elsevier GmbH. All rights reserved.

Perinatal supplementation of 4-phenylbutyrate and glutamine attenuates endoplasmic reticulum stress and improves colonic epithelial barrier function in rats born with intrauterine growth restriction.

PubMed

Désir-Vigné, Axel; Haure-Mirande, Vianney; de Coppet, Pierre; Darmaun, Dominique; Le Dréan, Gwenola; Segain, Jean-Pierre

2018-05-01

Intrauterine growth restriction (IUGR) can affect the structure and function of the intestinal barrier and increase digestive disease risk in adulthood. Using the rat model of maternal dietary protein restriction (8% vs. 20%), we found that the colon of IUGR offspring displayed decreased mRNA expression of epithelial barrier proteins MUC2 and occludin during development. This was associated with increased mRNA expression of endoplasmic reticulum (ER) stress marker XBP1s and increased colonic permeability measured in Ussing chambers. We hypothesized that ER stress contributes to colonic barrier alterations and that perinatal supplementation of dams with ER stress modulators, phenylbutyrate and glutamine (PG) could prevent these defects in IUGR offspring. We first demonstrated that ER stress induction by tunicamycin or thapsigargin increased the permeability of rat colonic tissues mounted in Ussing chamber and that PG treatment prevented this effect. Therefore, we supplemented the diet of control and IUGR dams with PG during gestation and lactation. Real-time polymerase chain reaction and histological analysis of colons from 120-day-old offspring revealed that perinatal PG treatment partially prevented the increased expression of ER stress markers but reversed the reduction of crypt depth and goblet cell number in IUGR rats. In dextran sodium sulfate-induced injury and recovery experiments, the colon of IUGR rats without perinatal PG treatment showed higher XBP1s mRNA levels and histological scores of inflammation than IUGR rats with perinatal PG treatment. In conclusion, these data suggest that perinatal supplementation with PG could alleviate ER stress and prevent epithelial barrier dysfunction in IUGR offspring. Copyright © 2017 Elsevier Inc. All rights reserved.

c-Rel Deficiency Increases Caspase-4 Expression and Leads to ER Stress and Necrosis in EBV-Transformed Cells

PubMed Central

Valentín-Acevedo, Aníbal; Sinquett, Frank L.; Covey, Lori R.

2011-01-01

LMP1-mediated activation of nuclear factor of kappaB (NF-κB) is critical for the ligand independent proliferation and cell survival of in vitro EBV-transformed lymphoblastoid cell lines (LCLs). Previous experiments revealed that a majority of LMP1-dependent responses are regulated by NF-κB. However, the extent that individual NF-κB family members are required for these responses, in particular, c-Rel, whose expression is restricted to mature hematopoietic cells, remains unclear. Here we report that low c-Rel expression in LCLs derived from a patient with hyper-IgM syndrome (Pt1), resulted in defects in proliferation and cell survival. In contrast to studies that associated loss of NF-κB with increased apoptosis, Pt1 LCLs failed to initiate apoptosis and alternatively underwent autophagy and necrotic cell death. Whereas the proliferation defect appeared linked to a c-Rel-associated decrease in c-myc expression, identified pro-survival and pro-apoptotic targets were expressed at or near control levels consistent with the absence of apoptosis. Ultrastructural examination of Pt1 LCLs revealed a high level of cellular and ER stress that was further supported by gene expression profiling showing the upregulation of several genes involved in stress and inflammation. Apoptosis-independent cell death was accompanied by increased expression of the inflammatory marker, caspase-4. Using gene overexpression and siRNA knockdown we demonstrated that levels of c-Rel directly modulated expression of caspase-4 as well as other ER stress genes. Overall, these findings reveal the importance of c-Rel in maintaining LCL viability and that decreased expression results in ER stress and a default response leading to necrotic cell death. PMID:21984918

Naringin Alleviates Diabetic Kidney Disease through Inhibiting Oxidative Stress and Inflammatory Reaction.

PubMed

Chen, Fenqin; Zhang, Ning; Ma, Xiaoyu; Huang, Ting; Shao, Ying; Wu, Can; Wang, Qiuyue

2015-01-01

Naringin, a flavanone glycoside extracted from Citrus grandis Osbeck, has a wide range of pharmacological effects. In the present study we aimed at demonstrating the protective effect of naringin against diabetic kidney disease (DKD) and elucidating its possible molecular mechanism underlying. The beneficial effect of naringin was assessed in rats with streptozotocin (STZ)-induced diabetes and high glucose-induced HBZY-1 cells. According to our results, first we found that naringin relieved kidney injury, improved renal function and inhibited collagen formation and renal interstitial fibrosis. Second, we confirmed that naringin restrained oxidative stress by activating Nrf2 antioxidant pathway. Moreover, the results suggested that naringin significantly resisted inflammatory reaction by inhibiting NF- κ B signaling pathway. Taken together, our results demonstrate that naringin effectively alleviates DKD, which provide theoretical basis for naringin clinically used to treatment of DKD.

Naringin Alleviates Diabetic Kidney Disease through Inhibiting Oxidative Stress and Inflammatory Reaction

PubMed Central

Chen, Fenqin; Zhang, Ning; Ma, Xiaoyu; Huang, Ting; Shao, Ying; Wu, Can; Wang, Qiuyue

2015-01-01

Naringin, a flavanone glycoside extracted from Citrus grandis Osbeck, has a wide range of pharmacological effects. In the present study we aimed at demonstrating the protective effect of naringin against diabetic kidney disease (DKD) and elucidating its possible molecular mechanism underlying. The beneficial effect of naringin was assessed in rats with streptozotocin (STZ)-induced diabetes and high glucose-induced HBZY-1 cells. According to our results, first we found that naringin relieved kidney injury, improved renal function and inhibited collagen formation and renal interstitial fibrosis. Second, we confirmed that naringin restrained oxidative stress by activating Nrf2 antioxidant pathway. Moreover, the results suggested that naringin significantly resisted inflammatory reaction by inhibiting NF- κ B signaling pathway. Taken together, our results demonstrate that naringin effectively alleviates DKD, which provide theoretical basis for naringin clinically used to treatment of DKD. PMID:26619044

Bilirubin Increases Insulin Sensitivity in Leptin-Receptor Deficient and Diet-Induced Obese Mice Through Suppression of ER Stress and Chronic Inflammation

PubMed Central

Dong, Huansheng; Huang, Hu; Yun, Xinxu; Kim, Do-sung; Yue, Yinan; Wu, Hongju; Sutter, Alton; Chavin, Kenneth D.; Otterbein, Leo E.; Adams, David B.; Kim, Young-Bum

2014-01-01

Obesity-induced endoplasmic reticulum (ER) stress causes chronic inflammation in adipose tissue and steatosis in the liver, and eventually leads to insulin resistance and type 2 diabetes (T2D). The goal of this study was to understand the mechanisms by which administration of bilirubin, a powerful antioxidant, reduces hyperglycemia and ameliorates obesity in leptin-receptor-deficient (db/db) and diet-induced obese (DIO) mouse models. db/db or DIO mice were injected with bilirubin or vehicle ip. Blood glucose and body weight were measured. Activation of insulin-signaling pathways, expression of inflammatory cytokines, and ER stress markers were measured in skeletal muscle, adipose tissue, and liver of mice. Bilirubin administration significantly reduced hyperglycemia and increased insulin sensitivity in db/db mice. Bilirubin treatment increased protein kinase B (PKB/Akt) phosphorylation in skeletal muscle and suppressed expression of ER stress markers, including the 78-kDa glucose-regulated protein (GRP78), CCAAT/enhancer-binding protein (C/EBP) homologous protein, X box binding protein (XBP-1), and activating transcription factor 4 in db/db mice. In DIO mice, bilirubin treatment significantly reduced body weight and increased insulin sensitivity. Moreover, bilirubin suppressed macrophage infiltration and proinflammatory cytokine expression, including TNF-α, IL-1β, and monocyte chemoattractant protein-1, in adipose tissue. In liver and adipose tissue of DIO mice, bilirubin ameliorated hepatic steatosis and reduced expression of GRP78 and C/EBP homologous protein. These results demonstrate that bilirubin administration improves hyperglycemia and obesity by increasing insulin sensitivity in both genetically engineered and DIO mice models. Bilirubin or bilirubin-increasing drugs might be useful as an insulin sensitizer for the treatment of obesity-induced insulin resistance and type 2 diabetes based on its profound anti-ER stress and antiinflammatory properties. PMID

Alleviating Parenting Stress in Parents with Intellectual Disabilities: A Randomized Controlled Trial of a Video-Feedback Intervention to Promote Positive Parenting

ERIC Educational Resources Information Center

Hodes, Marja W.; Meppelder, Marieke; Moor, Marleen; Kef, Sabina; Schuengel, Carlo

2017-01-01

Background: Adapted parenting support may alleviate the high levels of parenting stress experienced by many parents with intellectual disabilities. Methods: Parents with mild intellectual disabilities or borderline intellectual functioning were randomized to experimental (n = 43) and control (n = 42) conditions. Parents in both groups received…

Combination of proteasome and class I HDAC inhibitors induces apoptosis of NPC cells through an HDAC6-independent ER stress-induced mechanism.

PubMed

Hui, Kwai Fung; Chiang, Alan K S

2014-12-15

The current paradigm stipulates that inhibition of histone deacetylase (HDAC) 6 is essential for the combinatorial effect of proteasome and HDAC inhibitors for the treatment of cancers. Our study aims to investigate the effect of combining different class I HDAC inhibitors (without HDAC6 action) with a proteasome inhibitor on apoptosis of nasopharyngeal carcinoma (NPC). We found that combination of a proteasome inhibitor, bortezomib, and several class I HDAC inhibitors, including MS-275, apicidin and romidepsin, potently induced killing of NPC cells both in vitro and in vivo. Among the drug pairs, combination of bortezomib and romidepsin (bort/romidepsin) was the most potent and could induce apoptosis at low nanomolar concentrations. The apoptosis of NPC cells was reactive oxygen species (ROS)- and caspase-dependent but was independent of HDAC6 inhibition. Of note, bort/romidepsin might directly suppress the formation of aggresome through the downregulation of c-myc. In addition, two markers of endoplasmic reticulum (ER) stress-induced apoptosis, ATF-4 and CHOP/GADD153, were upregulated, whereas a specific inhibitor of caspase-4 (an initiator of ER stress-induced apoptosis) could suppress the apoptosis. When ROS level in the NPC cells was reduced to the untreated level, ER stress-induced caspase activation was abrogated. Collectively, our data demonstrate a model of synergism between proteasome and class I HDAC inhibitors in the induction of ROS-dependent ER stress-induced apoptosis of NPC cells, independent of HDAC6 inhibition, and provide the rationale to combine the more specific and potent class I HDAC inhibitors with proteasome inhibitors for the treatment of cancers. © 2014 UICC.

Cytosolic phosphoenolpyruvate carboxykinase is a response gene involved in porcine adipocyte adaptation to heat stress.

PubMed

Qu, Huan; Ajuwon, Kolapo M

2018-05-04

Heat stress (HS) leads to increased lipid storage and expression of cytosolic phosphoenolpyruvate carboxykinase (PCK1) in pig adipocytes. However, the importance of PCK1 activation and lipid storage in the adaptive response to HS is unknown. Therefore, in vitro experiments were conducted to investigate the effect of PCK1 inhibition with 3-mercaptopicolinic acid (3MPA) on lipid storage and adipocyte response during HS. In vitro culture of adipocytes under HS (41.0 °C) increased (P < 0.05) triacylglycerol accumulation compared with control (37.0 °C). HS increased (P < 0.05) reactive oxygen species level and 3MPA further upregulated (P < 0.05) its level. Heat shock protein 70 (HSP70) gene expression was induced (P < 0.05) by HS compared to control, and PCK1 inhibition with 3MPA attenuated (P < 0.05) its induction by HS. The endoplasmic reticulum (ER) stress markers, C/EBP homologous protein (CHOP) was also upregulated by HS and 3MPA further upregulated (P < 0.05) CHOP mRNA level. These results suggest that with inhibition of PCK1 during HS, in vitro cultured adipocytes were less able to induce adaptive responses such as upregulation of HSP70 and triglycerides, and this exacerbated ER stress during HS. Thus, PCK1 may function to alleviate ER stress that occurs during HS.

IRE1: ER stress sensor and cell fate executor

PubMed Central

Chen, Yani; Brandizzi, Federica

2013-01-01

Cells operate a signaling network termed unfolded protein response (UPR) to monitor protein-folding capacity in the endoplasmic reticulum (ER). IRE1 is an ER transmembrane sensor that activates UPR to maintain ER and cellular function. While mammalian IRE1 promotes cell survive, it can initiate apoptosis via decay of anti-apoptotic microRNAs. Convergent and divergent IRE1 characteristics between plants and animals underscore its significance in cellular homeostasis. This review provides an updated scenario of IRE1 signaling model, discusses emerging IRE1 sensing mechanisms, compares IRE1 features among species, and outlines exciting future directions in UPR research. PMID:23880584

Ripk3 promotes ER stress-induced necroptosis in cardiac IR injury: A mechanism involving calcium overload/XO/ROS/mPTP pathway.

PubMed

Zhu, Pingjun; Hu, Shunying; Jin, Qinhua; Li, Dandan; Tian, Feng; Toan, Sam; Li, Yang; Zhou, Hao; Chen, Yundai

2018-06-01

Receptor-interacting protein 3 (Ripk3)-mediated necroptosis contributes to cardiac ischaemia-reperfusion (IR) injury through poorly defined mechanisms. Our results demonstrated that Ripk3 was strongly upregulated in murine hearts subjected to IR injury and cardiomyocytes treated with LPS and H 2 O 2 . The higher level of Ripk3 was positively correlated to the infarction area expansion, cardiac dysfunction and augmented cardiomyocytes necroptosis. Function study further illustrated that upregulated Ripk3 evoked the endoplasmic reticulum (ER) stress, which was accompanied with an increase in intracellular Ca 2+ level ([Ca 2+ ]c) and xanthine oxidase (XO) expression. Activated XO raised cellular reactive oxygen species (ROS) that mediated the mitochondrial permeability transition pore (mPTP) opening and cardiomyocytes necroptosis. By comparison, genetic ablation of Ripk3 abrogated the ER stress and thus blocked the [Ca 2+ ]c overload-XO-ROS-mPTP pathways, favouring a pro-survival state that ultimately resulted in the inhibition of cardiomyocytes necroptosis in the setting of cardiac IR injury. In summary, the present study helps to elucidate how necroptosis is mediated by ER stress, via the calcium overload /XO/ROS/mPTP opening axis. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Basal autophagy maintains pancreatic acinar cell homeostasis and protein synthesis and prevents ER stress

PubMed Central

Antonucci, Laura; Fagman, Johan B.; Kim, Ju Youn; Todoric, Jelena; Gukovsky, Ilya; Mackey, Mason; Ellisman, Mark H.; Karin, Michael

2015-01-01

Pancreatic acinar cells possess very high protein synthetic rates as they need to produce and secrete large amounts of digestive enzymes. Acinar cell damage and dysfunction cause malnutrition and pancreatitis, and inflammation of the exocrine pancreas that promotes development of pancreatic ductal adenocarcinoma (PDAC), a deadly pancreatic neoplasm. The cellular and molecular mechanisms that maintain acinar cell function and whose dysregulation can lead to tissue damage and chronic pancreatitis are poorly understood. It was suggested that autophagy, the principal cellular degradative pathway, is impaired in pancreatitis, but it is unknown whether impaired autophagy is a cause or a consequence of pancreatitis. To address this question, we generated Atg7Δpan mice that lack the essential autophagy-related protein 7 (ATG7) in pancreatic epithelial cells. Atg7Δpan mice exhibit severe acinar cell degeneration, leading to pancreatic inflammation and extensive fibrosis. Whereas ATG7 loss leads to the expected decrease in autophagic flux, it also results in endoplasmic reticulum (ER) stress, accumulation of dysfunctional mitochondria, oxidative stress, activation of AMPK, and a marked decrease in protein synthetic capacity that is accompanied by loss of rough ER. Atg7Δpan mice also exhibit spontaneous activation of regenerative mechanisms that initiate acinar-to-ductal metaplasia (ADM), a process that replaces damaged acinar cells with duct-like structures. PMID:26512112

Caffeine Induces the Stress Response and Up-Regulates Heat Shock Proteins in Caenorhabditis elegans.

PubMed

Al-Amin, Mohammad; Kawasaki, Ichiro; Gong, Joomi; Shim, Yhong-Hee

2016-02-01

Caffeine has both positive and negative effects on physiological functions in a dose-dependent manner. C. elegans has been used as an animal model to investigate the effects of caffeine on development. Caffeine treatment at a high dose (30 mM) showed detrimental effects and caused early larval arrest. We performed a comparative proteomic analysis to investigate the mode of action of high-dose caffeine treatment in C. elegans and found that the stress response proteins, heat shock protein (HSP)-4 (endoplasmic reticulum [ER] chaperone), HSP-6 (mitochondrial chaperone), and HSP-16 (cytosolic chaperone), were induced and their expression was regulated at the transcriptional level. These findings suggest that high-dose caffeine intake causes a strong stress response and activates all three stress-response pathways in the worms, including the ER-, mitochondrial-, and cytosolic pathways. RNA interference of each hsp gene or in triple combination retarded growth. In addition, caffeine treatment stimulated a food-avoidance behavior (aversion phenotype), which was enhanced by RNAi depletion of the hsp-4 gene. Therefore, up-regulation of hsp genes after caffeine treatment appeared to be the major responses to alleviate stress and protect against developmental arrest.

Electroacupuncture alleviates stress-induced visceral hypersensitivity through an opioid system in rats

PubMed Central

Zhou, Yuan-Yuan; Wanner, Natalie J; Xiao, Ying; Shi, Xuan-Zheng; Jiang, Xing-Hong; Gu, Jian-Guo; Xu, Guang-Yin

2012-01-01

AIM: To investigate whether stress-induced visceral hypersensitivity could be alleviated by electroacupuncture (EA) and whether EA effect was mediated by endogenous opiates. METHODS: Six to nine week-old male Sprague-Dawley rats were used in this study. Visceral hypersensitivity was induced by a 9-d heterotypic intermittent stress (HIS) protocol composed of 3 randomly stressors, which included cold restraint stress at 4 °C for 45 min, water avoidance stress for 60 min, and forced swimming stress for 20 min, in adult male rats. The extent of visceral hypersensitivity was quantified by electromyography or by abdominal withdrawal reflex (AWR) scores of colorectal distension at different distention pressures (20 mmHg, 40 mmHg, 60 mmHg and 80 mmHg). AWR scores either 0, 1, 2, 3 or 4 were obtained by a blinded observer. EA or sham EA was performed at classical acupoint ST-36 (Zu-San-Li) or BL-43 (Gao-Huang) in both hindlimbs of rats for 30 min. Naloxone (NLX) or NLX methiodide (m-NLX) was administered intraperitoneally to HIS rats in some experiments. RESULTS: HIS rats displayed an increased sensitivity to colorectal distention, which started from 6 h (the first measurement), maintained for 24 h, and AWR scores returned to basal levels at 48 h and 7 d after HIS compared to pre-HIS baseline at different distention pressures. The AWR scores before HIS were 0.6 ± 0.2, 1.3 ± 0.2, 1.9 ± 0.2 and 2.3 ± 0.2 for 20 mmHg, 40 mmHg, 60 mmHg and 80 mmHg distention pressures, respectively. Six hours after termination of the last stressor, the AWR scores were 2.0 ± 0.1, 2.5 ± 0.1, 2.8 ± 0.2 and 3.5 ± 0.2 for 20 mmHg, 40 mmHg, 60 mmHg and 80 mmHg distention pressures, respectively. EA given at classical acupoint ST-36 in both hindlimbs for 30 min significantly attenuated the hypersensitive responses to colorectal distention in HIS rats compared with sham EA treatment [AWRs at 20 mmHg: 2.0 ± 0.2 vs 0.7 ± 0.1, P = 4.23 711 E-4; AWRs at 40 mmHg: 2.6 ± 0.2 vs 1.5 ± 0.2, P

Proteus mirabilis alleviates zinc toxicity by preventing oxidative stress in maize (Zea mays) plants.

PubMed

Islam, Faisal; Yasmeen, Tahira; Riaz, Muhammad; Arif, Muhammad Saleem; Ali, Shafaqat; Raza, Syed Hammad

2014-12-01

Plant-associated bacteria can have beneficial effects on the growth and health of their host. However, the role of plant growth promoting bacteria (PGPR), under metal stress, has not been widely investigated. The present study investigated the possible mandatory role of plant growth promoting rhizobacteria in protecting plants from zinc (Zn) toxicity. The exposure of maize plants to 50µM zinc inhibited biomass production, decreased chlorophyll, total soluble protein and strongly increased accumulation of Zn in both root and shoot. Similarly, Zn enhanced hydrogen peroxide, electrolyte leakage and lipid peroxidation as indicated by malondaldehyde accumulation. Pre-soaking with novel Zn tolerant bacterial strain Proteus mirabilis (ZK1) isolated zinc (Zn) contaminated soil, alleviated the negative effect of Zn on growth and led to a decrease in oxidative injuries caused by Zn. Furthermore, strain ZK1 significantly enhanced the activities of catalase, guaiacol peroxidase, superoxide dismutase and ascorbic acid but lowered the Proline accumulation in Zn stressed plants. The results suggested that the inoculation of Zea mays plants with P. mirabilis during an earlier growth period could be related to its plant growth promoting activities and avoidance of cumulative damage upon exposure to Zn, thus reducing the negative consequences of oxidative stress caused by heavy metal toxicity. Copyright © 2014 Elsevier Inc. All rights reserved.

2-Chlorohexadecanoic acid induces ER stress and mitochondrial dysfunction in brain microvascular endothelial cells.

PubMed

Bernhart, Eva; Kogelnik, Nora; Prasch, Jürgen; Gottschalk, Benjamin; Goeritzer, Madeleine; Depaoli, Maria Rosa; Reicher, Helga; Nusshold, Christoph; Plastira, Ioanna; Hammer, Astrid; Fauler, Günter; Malli, Roland; Graier, Wolfgang F; Malle, Ernst; Sattler, Wolfgang

2018-05-01

Peripheral leukocytes induce blood-brain barrier (BBB) dysfunction through the release of cytotoxic mediators. These include hypochlorous acid (HOCl) that is formed via the myeloperoxidase-H 2 O 2 -chloride system of activated phagocytes. HOCl targets the endogenous pool of ether phospholipids (plasmalogens) generating chlorinated inflammatory mediators like e.g. 2-chlorohexadecanal and its conversion product 2-chlorohexadecanoic acid (2-ClHA). In the cerebrovasculature these compounds inflict damage to brain microvascular endothelial cells (BMVEC) that form the morphological basis of the BBB. To follow subcellular trafficking of 2-ClHA we synthesized a 'clickable' alkyne derivative (2-ClHyA) that phenocopied the biological activity of the parent compound. Confocal and superresolution structured illumination microscopy revealed accumulation of 2-ClHyA in the endoplasmic reticulum (ER) and mitochondria of human BMVEC (hCMEC/D3 cell line). 2-ClHA and its alkyne analogue interfered with protein palmitoylation, induced ER-stress markers, reduced the ER ATP content, and activated transcription and secretion of interleukin (IL)-6 as well as IL-8. 2-ClHA disrupted the mitochondrial membrane potential and induced procaspase-3 and PARP cleavage. The protein kinase R-like ER kinase (PERK) inhibitor GSK2606414 suppressed 2-ClHA-mediated activating transcription factor 4 synthesis and IL-6/8 secretion, but showed no effect on endothelial barrier dysfunction and cleavage of procaspase-3. Our data indicate that 2-ClHA induces potent lipotoxic responses in brain endothelial cells and could have implications in inflammation-induced BBB dysfunction. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

IRE1: ER stress sensor and cell fate executor.

PubMed

Chen, Yani; Brandizzi, Federica

2013-11-01

Cells operate a signaling network termed the unfolded protein response (UPR) to monitor protein-folding capacity in the endoplasmic reticulum (ER). Inositol-requiring enzyme 1 (IRE1) is an ER transmembrane sensor that activates the UPR to maintain the ER and cellular function. Although mammalian IRE1 promotes cell survival, it can initiate apoptosis via decay of antiapoptotic miRNAs. Convergent and divergent IRE1 characteristics between plants and animals underscore its significance in cellular homeostasis. This review provides an updated scenario of the IRE1 signaling model, discusses emerging IRE1 sensing mechanisms, compares IRE1 features among species, and outlines exciting future directions in UPR research. Copyright © 2013 Elsevier Ltd. All rights reserved.

Açaí (Euterpe oleracea Mart.) attenuates alcohol-induced liver injury in rats by alleviating oxidative stress and inflammatory response.

PubMed

Zhou, Jianyu; Zhang, Jianjun; Wang, Chun; Qu, Shengsheng; Zhu, Yingli; Yang, Zhihui; Wang, Linyuan

2018-01-01

The present study aimed to investigate the therapeutic effects of Euterpe oleracea Mart. (EO) on alcoholic liver diseases (ALD). A total of 30 Wistar rats were randomly divided into three groups (10 rats per group), including alcohol group (alcohol intake), EO group (alcohol + EO puree intake) and control group (distilled water intake). The activity of superoxide dismutase (SOD) and alkaline phosphatase (ALP), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and the levels of cholesterol (CHO), triglyceride (TG), malondialdehyde (MDA) and glutathione (GSH) in the serum as well as the liver tissue levels of interleukin 8 (IL-8), tumor necrosis factor-α (TNF-α) and transforming growth factor-β (TGF-β) were measured. Histopathological changes in liver tissues were observed by hematoxylin and eosin staining. Reverse-transcription quantitative PCR analysis was performed for detecting the expression of nuclear factor (NF)-κB and CD68. The results indicated that EO intake significantly decreased ALT, AST, ALP, TG and CHO as well as the hepatic index in alcohol-treated rats. In addition, EO treatment relieved alcohol-induced oxidative stress by decreasing the levels of MDA and TG, and increasing the activity of SOD and GSH levels. In addition, the expression of TNF-α, TGF-β, IL-8, NF-κB and CD-68 in the liver were decreased by EO treatment. Furthermore, EO intake alleviated the histopathological liver damage, including severe steatosis and abundant infiltrated inflammatory cells. In conclusion, EO alleviated alcohol-induced liver injury in rats by alleviating oxidative stress and inflammatory response.

Açaí (Euterpe oleracea Mart.) attenuates alcohol-induced liver injury in rats by alleviating oxidative stress and inflammatory response

PubMed Central

Zhou, Jianyu; Zhang, Jianjun; Wang, Chun; Qu, Shengsheng; Zhu, Yingli; Yang, Zhihui; Wang, Linyuan

2018-01-01

The present study aimed to investigate the therapeutic effects of Euterpe oleracea Mart. (EO) on alcoholic liver diseases (ALD). A total of 30 Wistar rats were randomly divided into three groups (10 rats per group), including alcohol group (alcohol intake), EO group (alcohol + EO puree intake) and control group (distilled water intake). The activity of superoxide dismutase (SOD) and alkaline phosphatase (ALP), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and the levels of cholesterol (CHO), triglyceride (TG), malondialdehyde (MDA) and glutathione (GSH) in the serum as well as the liver tissue levels of interleukin 8 (IL-8), tumor necrosis factor-α (TNF-α) and transforming growth factor-β (TGF-β) were measured. Histopathological changes in liver tissues were observed by hematoxylin and eosin staining. Reverse-transcription quantitative PCR analysis was performed for detecting the expression of nuclear factor (NF)-κB and CD68. The results indicated that EO intake significantly decreased ALT, AST, ALP, TG and CHO as well as the hepatic index in alcohol-treated rats. In addition, EO treatment relieved alcohol-induced oxidative stress by decreasing the levels of MDA and TG, and increasing the activity of SOD and GSH levels. In addition, the expression of TNF-α, TGF-β, IL-8, NF-κB and CD-68 in the liver were decreased by EO treatment. Furthermore, EO intake alleviated the histopathological liver damage, including severe steatosis and abundant infiltrated inflammatory cells. In conclusion, EO alleviated alcohol-induced liver injury in rats by alleviating oxidative stress and inflammatory response. PMID:29399060

Melatonin Alleviates Liver Apoptosis in Bile Duct Ligation Young Rats.

PubMed

Sheen, Jiunn-Ming; Chen, Yu-Chieh; Hsu, Mei-Hsin; Tain, You-Lin; Huang, Ying-Hsien; Tiao, Mao-Meng; Li, Shih-Wen; Huang, Li-Tung

2016-08-20

Bile duct ligation (BDL)-treated rats display cholestasis and liver damages. The potential protective activity of melatonin in young BDL rats in terms of apoptosis, mitochondrial function, and endoplasmic reticulum (ER) homeostasis has not yet been evaluated. Three groups of young male Sprague-Dawley rats were used: one group received laparotomy (Sham), a second group received BDL for two weeks (BDL), and a third group received BDL and intraperitoneal melatonin (100 mg/day) for two weeks (BDL + M). BDL group rats showed liver apoptosis, increased pro-inflamamtory mediators, caspases alterations, anti-apoptotic factors changes, and dysfunction of ER homeostasis. Melatonin effectively reversed apoptosis, mainly through intrinsic pathway and reversed ER stress. In addition, in vitro study showed melatonin exerted its effect mainly through the melatonin 2 receptor (MT2) in HepG2 cells. In conclusion, BDL in young rats caused liver apoptosis. Melatonin rescued the apoptotic changes via the intrinsic pathway, and possibly through the MT2 receptor. Melatonin also reversed ER stress induced by BDL.

Selenium and vitamin E together improve intestinal epithelial barrier function and alleviate oxidative stress in heat-stressed pigs.

PubMed

Liu, Fan; Cottrell, Jeremy J; Furness, John B; Rivera, Leni R; Kelly, Fletcher W; Wijesiriwardana, Udani; Pustovit, Ruslan V; Fothergill, Linda J; Bravo, David M; Celi, Pietro; Leury, Brian J; Gabler, Nicholas K; Dunshea, Frank R

2016-07-01

What is the central question of this study? Oxidative stress may play a role in compromising intestinal epithelial barrier integrity in pigs subjected to heat stress, but it is unknown whether an increase of dietary antioxidants (selenium and vitamin E) could alleviate gut leakiness in heat-stressed pigs. What is the main finding and its importance? Levels of dietary selenium (1.0 p.p.m.) and vitamin E (200 IU kg(-1) ) greater than those usually recommended for pigs reduced intestinal leakiness caused by heat stress. This finding suggests that oxidative stress plays a role in compromising intestinal epithelial barrier integrity in heat-stressed pigs and also provides a nutritional strategy for mitigating these effects. Heat stress compromises the intestinal epithelial barrier integrity of mammals through mechanisms that may include oxidative stress. Our objective was to test whether dietary supplementation with antioxidants, selenium (Se) and vitamin E (VE), protects intestinal epithelial barrier integrity in heat-stressed pigs. Female growing pigs (n = 48) were randomly assigned to four diets containing from 0.2 p.p.m. Se and 17 IU kg(-1) VE (control, National Research Council recommended) to 1.0 p.p.m. Se and 200 IU kg(-1) VE for 14 days. Six pigs from each dietary treatment were then exposed to either thermoneutral (20°C) or heat-stress conditions (35°C 09.00-17.00 h and 28°C overnight) for 2 days. Transepithelial electrical resistance and fluorescein isothiocyanate-dextran (4 kDa; FD4) permeability were measured in isolated jejunum and ileum using Ussing chambers. Rectal temperature, respiratory rate and intestinal HSP70 mRNA abundance increased (all P < 0.001), and respiratory alkalosis occurred, suggesting that pigs were heat stressed. Heat stress also increased FD4 permeability and decreased transepithelial electrical resistance (both P < 0.01). These changes were associated with changes indicative of oxidative stress, a decreased

Phosphorus improves arsenic phytoremediation by Anadenanthera peregrina by alleviating induced oxidative stress.

PubMed

Gomes, M P; Carvalho, M; Carvalho, G S; Marques, T C L L S M; Garcia, Q S; Guilherme, L R G; Soares, A M

2013-01-01

Due to similarities in their chemical behaviors, studies examining interactions between arsenic (As)--in special arsenate--and phosphorus (P) are important for better understanding arsenate uptake, toxicity, and accumulation in plants. We evaluated the effects of phosphate addition on plant biomass and on arsenate and phosphate uptake by Anadenanthera peregrina, an important Brazilian savanna legume. Plants were grown for 35 days in substrates that received combinations of 0, 10, 50, and 100 mg kg(-1) arsenate and 0, 200, and 400 mg kg(-1) phosphate. The addition of P increased the arsenic-phytoremediation capacity of A. peregrina by increasing As accumulation, while also alleviating As-induced oxidative stress. Arsenate phytotoxicity in A. peregrina is due to lipid peroxidation, but not hydrogen peroxide accumulation. Added P also increased the activity of important reactive oxygen species-scavenging enzymes (catalase and ascorbate peroxidase) that help prevent lipid peroxidation in leaves. Our findings suggest that applying P represents a feasible strategy for more efficient As phytoremediation using A. peregrina.

COPII-Dependent ER Export: A Critical Component of Insulin Biogenesis and β-Cell ER Homeostasis.

PubMed

Fang, Jingye; Liu, Ming; Zhang, Xuebao; Sakamoto, Takeshi; Taatjes, Douglas J; Jena, Bhanu P; Sun, Fei; Woods, James; Bryson, Tim; Kowluru, Anjaneyulu; Zhang, Kezhong; Chen, Xuequn

2015-08-01

Pancreatic β-cells possess a highly active protein synthetic and export machinery in the endoplasmic reticulum (ER) to accommodate the massive production of proinsulin. ER homeostasis is vital for β-cell functions and is maintained by the delicate balance between protein synthesis, folding, export, and degradation. Disruption of ER homeostasis by diabetes-causing factors leads to β-cell death. Among the 4 components to maintain ER homeostasis in β-cells, the role of ER export in insulin biogenesis is the least understood. To address this knowledge gap, the present study investigated the molecular mechanism of proinsulin ER export in MIN6 cells and primary islets. Two inhibitory mutants of the secretion-associated RAS-related protein (Sar)1 small GTPase, known to specifically block coat protein complex II (COPII)-dependent ER export, were overexpressed in β-cells using recombinant adenoviruses. Results from this approach, as well as small interfering RNA-mediated Sar1 knockdown, demonstrated that defective Sar1 function blocked proinsulin ER export and abolished its conversion to mature insulin in MIN6 cells, isolated mouse, and human islets. It is further revealed, using an in vitro vesicle formation assay, that proinsulin was packaged into COPII vesicles in a GTP- and Sar1-dependent manner. Blockage of COPII-dependent ER exit by Sar1 mutants strongly induced ER morphology change, ER stress response, and β-cell apoptosis. These responses were mediated by the PKR (double-stranded RNA-dependent kinase)-like ER kinase (PERK)/eukaryotic translation initiation factor 2α (p-eIF2α) and inositol-requiring protein 1 (IRE1)/x-box binding protein 1 (Xbp1) pathways but not via activating transcription factor 6 (ATF6). Collectively, results from the study demonstrate that COPII-dependent ER export plays a vital role in insulin biogenesis, ER homeostasis, and β-cell survival.

The glutathione mimic ebselen inhibits oxidative stress but not endoplasmic reticulum stress in endothelial cells.

PubMed

Ahwach, Salma Makhoul; Thomas, Melanie; Onstead-Haas, Luisa; Mooradian, Arshag D; Haas, Michael J

2015-08-01

Reactive oxygen species are associated with cardiovascular disease, diabetes, and atherosclerosis, yet the use of antioxidants in clinical trials has been ineffective at improving outcomes. In endothelial cells, high-dextrose-induced oxidative stress and endoplasmic reticulum stress promote endothelial dysfunction leading to the recruitment and activation of peripheral blood lymphocytes and the breakdown of barrier function. Ebselen, a glutathione peroxidase 1 (GPX1) mimic, has been shown to improve β-cell function in diabetes and prevent atherosclerosis. To determine if ebselen inhibits both oxidative stress and endoplasmic reticulum (ER) stress in endothelial cells, we examined its effects in human umbilical vein endothelial cells (HUVEC) and human coronary artery endothelial cells (HCAEC) with and without high-dextrose. Oxidative stress and ER stress were measured by 2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo[1,2-A]pyrazin-3-one hydrochloride chemiluminescence and ER stress alkaline phosphatase assays, respectively. GPX1 over-expression and knockdown were performed by transfecting cells with a GPX1 expression construct or a GPX1-specific siRNA, respectively. Ebselen inhibited dextrose-induced oxidative stress but not ER stress in both HUVEC and HCAEC. Ebselen also had no effect on tunicamycin-induced ER stress in HCAEC. Furthermore, augmentation of GPX1 activity directly by sodium selenite supplementation or transfection of a GPX1 expression plasmid decreased dextrose-induced oxidative stress but not ER stress, while GPX1 knockout enhanced oxidative stress but had no effect on ER stress. These results suggest that ebselen targets only oxidative stress but not ER stress. Copyright © 2015. Published by Elsevier Inc.

Crocin and quercetin prevent PAT-induced apoptosis in mammalian cells: Involvement of ROS-mediated ER stress pathway.

PubMed

Boussabbeh, Manel; Prola, Alexandre; Ben Salem, Intidhar; Guilbert, Arnaud; Bacha, Hassen; Lemaire, Christophe; Abis-Essefi, Salwa

2016-12-01

Patulin (PAT) is a secondary metabolite produced by several species of the genera of Penicillium, Aspergillus, and Byssochlamys that can be found in rotting fruits, especially in apples and apple-based products. Exposure to this mycotoxin has been reported to induce intestinal and kidney injuries. The mechanism underlying such toxicity has been linked to the induction of apoptosis which occurred with reactive oxygen species production and endoplasmic reticulum (ER) stress induction. This study aimed to evaluate the effect of the two common dietary compounds Quercetin (QUER), a natural flavonoid, and Crocin (CRO), a natural carotenoid, on PAT-induced toxicity in human colon carcinoma (HCT116) and embryonic kidney cells (HEK293). We showed that antioxidant properties of QUER and CRO help to prevent ER stress activation and lipid peroxidation as evidenced by the reduction in GRP78 and GADD34 expressions and the decrease in malondialdehyde production. Furthermore, we demonstrated their ability to re-establish the loss of the mitochondrial membrane potential to inhibit caspase 3 activation and DNA fragmentation. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1851-1858, 2016. © 2015 Wiley Periodicals, Inc.

TMEM258 Is a Component of the Oligosaccharyltransferase Complex Controlling ER Stress and Intestinal Inflammation.

PubMed

Graham, Daniel B; Lefkovith, Ariel; Deelen, Patrick; de Klein, Niek; Varma, Mukund; Boroughs, Angela; Desch, A Nicole; Ng, Aylwin C Y; Guzman, Gaelen; Schenone, Monica; Petersen, Christine P; Bhan, Atul K; Rivas, Manuel A; Daly, Mark J; Carr, Steven A; Wijmenga, Cisca; Xavier, Ramnik J

2016-12-13

Significant insights into disease pathogenesis have been gleaned from population-level genetic studies; however, many loci associated with complex genetic disease contain numerous genes, and phenotypic associations cannot be assigned unequivocally. In particular, a gene-dense locus on chromosome 11 (61.5-61.65 Mb) has been associated with inflammatory bowel disease, rheumatoid arthritis, and coronary artery disease. Here, we identify TMEM258 within this locus as a central regulator of intestinal inflammation. Strikingly, Tmem258 haploinsufficient mice exhibit severe intestinal inflammation in a model of colitis. At the mechanistic level, we demonstrate that TMEM258 is a required component of the oligosaccharyltransferase complex and is essential for N-linked protein glycosylation. Consequently, homozygous deficiency of Tmem258 in colonic organoids results in unresolved endoplasmic reticulum (ER) stress culminating in apoptosis. Collectively, our results demonstrate that TMEM258 is a central mediator of ER quality control and intestinal homeostasis. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

CURCUMIN ALLEVIATES LUMBAR RADICULOPATHY BY REDUCING NEUROINFLAMMATION, OXIDATIVE STRESS AND NOCICEPTIVE FACTORS

PubMed Central

Xiao, L.; Ding, M.; Fernandez, A.; Zhao, P.; Jin, L.; Li, X.

2017-01-01

Current non-surgical treatments for lumbar radiculopathy [e.g. epidural steroids and Tumour necrosis factor-α (TNF-α) antagonists] are neither effective nor safe. As a non-toxic natural product, curcumin possesses an exceptional anti-inflammatory profile. We hypothesised that curcumin alleviates lumbar radiculopathy by attenuating neuroinflammation, oxidative stress and nociceptive factors. In a dorsal root ganglion (DRG) culture, curcumin effectively inhibited TNF-α-induced neuroinflammation, in a dose-dependent manner, as shown by mRNA and protein expression of IL-6 and COX-2. Such effects might be mediated via protein kinase B (AKT) and extracellular signal regulated kinase (ERK) pathways. Also, a similar effect in combating TNF-α-induced neuroinflammation was observed in isolated primary neurons. In addition, curcumin protected neurons from TNF-α-triggered excessive reactive oxygen species (ROS) production and cellular apoptosis and, accordingly, promoted mRNA expression of the anti-oxidative enzymes haem oxygenase-1, catalase and superoxide dismutase-2. Intriguingly, electronic von Frey test suggested that intraperitoneal injection of curcumin significantly abolished ipsilateral hyperalgesia secondary to disc herniation in mice, for up to 2 weeks post-surgery. Such in vivo pain alleviation could be attributed to the suppression, observed in DRG explant culture, of TNF-α-elicited neuropeptides, such as substance P and calcitonin gene-related peptide. Surprisingly, micro-computed tomography (µCT) data suggested that curcumin treatment could promote disc height recovery following disc herniation. Alcian blue/picrosirius red staining confirmed that systemic curcumin administration promoted regeneration of extracellular matrix proteins, visualised by presence of abundant newly-formed collagen and proteoglycan content in herniated disc. Our study provided pre-clinical evidence for expediting this natural, non-toxic pleiotropic agent to become a new and safe

Curcumin alleviates lumbar radiculopathy by reducing neuroinflammation, oxidative stress and nociceptive factors.

PubMed

Xiao, L; Ding, M; Fernandez, A; Zhao, P; Jin, L; Li, X

2017-05-09

Current non-surgical treatments for lumbar radiculopathy [e.g. epidural steroids and Tumour necrosis factor-α (TNF-α) antagonists] are neither effective nor safe. As a non-toxic natural product, curcumin possesses an exceptional anti-inflammatory profile. We hypothesised that curcumin alleviates lumbar radiculopathy by attenuating neuroinflammation, oxidative stress and nociceptive factors. In a dorsal root ganglion (DRG) culture, curcumin effectively inhibited TNF-α-induced neuroinflammation, in a dose-dependent manner, as shown by mRNA and protein expression of IL-6 and COX-2. Such effects might be mediated via protein kinase B (AKT) and extracellular signal regulated kinase (ERK) pathways. Also, a similar effect in combating TNF-α-induced neuroinflammation was observed in isolated primary neurons. In addition, curcumin protected neurons from TNF-α-triggered excessive reactive oxygen species (ROS) production and cellular apoptosis and, accordingly, promoted mRNA expression of the anti-oxidative enzymes haem oxygenase-1, catalase and superoxide dismutase-2. Intriguingly, electronic von Frey test suggested that intraperitoneal injection of curcumin significantly abolished ipsilateral hyperalgesia secondary to disc herniation in mice, for up to 2 weeks post-surgery. Such in vivo pain alleviation could be attributed to the suppression, observed in DRG explant culture, of TNF-α-elicited neuropeptides, such as substance P and calcitonin gene-related peptide. Surprisingly, micro-computed tomography (μCT) data suggested that curcumin treatment could promote disc height recovery following disc herniation. Alcian blue/picrosirius red staining confirmed that systemic curcumin administration promoted regeneration of extracellular matrix proteins, visualised by presence of abundant newly-formed collagen and proteoglycan content in herniated disc. Our study provided pre-clinical evidence for expediting this natural, non-toxic pleiotropic agent to become a new and safe

Schisandrin B alleviates acute oxidative stress via modulating Nrf2/Keap1-mediated antioxidant pathway.

PubMed

Ying, Wu; Li, Zheng-Cai; Li-Qing, Yao; Mai, Li; Mei, Tang

2018-05-09

Schisandrin B (Sch B), one of Fructus Schisandrae's main effective components, protects neurons from oxidative stress in the central nervous system. Here we investigated the neuroprotective effect of Sch B in the acute oxidative stress damage and attempted to define the possible mechanisms. From the elevated plus maze (EPM) and open field test (OFT), we found that forcing swimming, an acute stressor, significantly induced anxiety-like behavior which was alleviated by Sch B (p.o.) treatment. In addition, the Sch B treatment suppressed toxicity, malondialdehyde (MDA) and reactive oxygen species (ROS), an important factor for neuron damage. The antioxidant molecules under the control of Nrf2 pathway, such as superoxide dismutase (SOD) and glutathione (GSH), were significantly increased by Sch B treatment. Moreover, a higher percentage of intact cells in the amygdala further verified the neuroprotective effect of Sch B in Nissl staining. Several proteins such as Nrf2 and its endogenous inhibitor Keap1, were abnormal expressed in force swimming mice but were significantly reversed by Sch B treatment. Herein, our results suggested that Sch B may be a potential therapeutic agent against anxiety disease that is associated with oxidative stress. The possible mechanism is attributed to its neuroprotection through enhancing antioxidant effect.

MicroRNAs meet calcium: joint venture in ER proteostasis.

PubMed

Finger, Fabian; Hoppe, Thorsten

2014-11-04

The endoplasmic reticulum (ER) is a cellular compartment that has a key function in protein translation and folding. Maintaining its integrity is of fundamental importance for organism's physiology and viability. The dynamic regulation of intraluminal ER Ca(2+) concentration directly influences the activity of ER-resident chaperones and stress response pathways that balance protein load and folding capacity. We review the emerging evidence that microRNAs play important roles in adjusting these processes to frequently changing intracellular and environmental conditions to modify ER Ca(2+) handling and storage and maintain ER homeostasis. Copyright © 2014, American Association for the Advancement of Science.

Silicon nanoparticles more effectively alleviated UV-B stress than silicon in wheat (Triticum aestivum) seedlings.

PubMed

Tripathi, Durgesh Kumar; Singh, Swati; Singh, Vijay Pratap; Prasad, Sheo Mohan; Dubey, Nawal Kishore; Chauhan, Devendra Kumar

2017-01-01

The role of silicon (Si) in alleviating biotic as well as abiotic stresses is well known. However, the potential of silicon nanoparticle (SiNP) in regulating abiotic stress and associated mechanisms have not yet been explored. Therefore, in the present study hydroponic experiments were conducted to investigate whether Si or SiNp are more effective in the regulation of UV-B stress. UV-B (ambient and enhanced) radiation caused adverse effect on growth of wheat (Triticum aestivum) seedlings, which was accompanied by declined photosynthetic performance and altered vital leaf structures. Levels of superoxide radical and H 2 O 2 were enhanced by UV-B as also evident from their histochemical stainings, which was accompanied by increased lipid peroxidation (LPO) and electrolyte leakage. Activities of superoxide dismutase and ascorbate peroxidase were inhibited by UV-B while catalase and guaiacol peroxidase, and all non-enzymatic antioxidants were stimulated by UV-B. Although, nitric oxide (NO) content was increased at all tested combinations, but its maximum content was observed under SiNps together with UV-B enhanced treatment. Pre-additions of SiNp as well as Si protected wheat seedlings against UV-B by regulating oxidative stress through enhanced antioxidants. Data indicate that SiNp might have protected wheat seedlings through NO-mediated triggering of antioxidant defense system, which subsequently counterbalance reactive oxygen species-induced damage to photosynthesis. Further, SiNp appear to be more effective in reducing UV-B stress than Si, which is related to its greater availability to wheat seedlings. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Endoplasmic Reticulum Stress in Sepsis

PubMed Central

Khan, Mohammad Moshahid; Yang, Weng-Lang; Wang, Ping

2015-01-01

Sepsis is an enormous public health issue and the leading cause of death in critically ill patients in intensive care units (ICU). Overwhelming inflammation, characterized by cytokine storm, oxidative threats, and neutrophil sequestration is an underlying component of sepsis-associated organ failure. Despite recent advances in sepsis research, there is still no effective treatment available beyond the standard of care and supportive therapy. To reduce sepsis-related mortality, a better understanding of the biological mechanism associated with the sepsis is essential. Endoplasmic reticulum (ER), a subcellular organelle is responsible for the facilitation of protein folding and assembly and involved in several other physiological activities. Under the stress and inflammation condition, ER loses the homeostasis in its function, which is termed as ER stress. During ER stress, unfolded protein response (UPR) is activated to restore ER function to its normal balance. However, once the stress is beyond the compensatory capacity of UPR or protracted, the apoptosis would be initiated by triggering cell injuries, even to cell death. As such, ER stress and UPR are reported to be implicated in several pathological and inflammatory conditions. Although the detrimental role of ER stress during infections has been demonstrated, there is growing evidences that ER stress participate in the pathogenesis of sepsis. In this review, we summarize the current research in the context of ER stress and UPR signaling associated with sepsis and its related clinical conditions, such as trauma- hemorrhage, and ischemia/reperfusion (I/R) injury. We also discuss the potential implication of ER stress as a novel therapeutic target and prognostic marker in patients with sepsis. PMID:26125088

Hydrogen sulfide alleviates postharvest ripening and senescence of banana by antagonizing the effect of ethylene

PubMed Central

Hu, Lan-Ying; Chen, Xiao-Yan; Li, Yan-Hong; Yang, Ying; Yang, Feng

2017-01-01

Accumulating evidence shows that hydrogen sulfide (H2S) acts as a multifunctional signaling molecule in plants, whereas the interaction between H2S and ethylene is still unclear. In the present study we investigated the role of H2S in ethylene-promoted banana ripening and senescence by the application of ethylene released from 1.0 g·L−1 ethephon solution or H2S with 1 mM sodium hydrosulfide (NaHS) as the donor or in combination. Fumigation with ethylene was found to accelerate banana ripening and H2S treatment effectively alleviated ethylene-induced banana peel yellowing and fruit softening in parallel with decreased activity of polygalacturonase (PG). Ethylene+H2S treatment also delayed the decreases in chlorophyll and total phenolics, and increased the accumulation of flavonoid, whereas decreased the contents of carotenoid, soluble protein in banana peel and reducing sugar in pulp compared with ethylene treatment alone. Besides, ethylene+H2S treatment suppressed the accumulation of superoxide radicals (·O2−), hydrogen peroxide (H2O2) and malondialdehyde (MDA) which accumulated highly in ethylene-treated banana peels. Furthermore H2S enhanced total antioxidant capacity in ethylene-treated banana peels with the 2,2’-azobis(3-ethylbenz-thiazoline-6-sulfonic acid (ABTS) assay. The result of quantitative real-time PCR showed that the combined treatment of ethylene with H2S down-regulated the expression of ethylene synthesis genes MaACS1, MaACS2 and MaACO1 and pectate lyase MaPL compared with ethylene treatment, while the expression of ethylene receptor genes MaETR, MaERS1 and MaERS2 was enhanced in combination treatment compared with ethylene alone. In all, it can be concluded that H2S alleviates banana fruit ripening and senescence by antagonizing the effect of ethylene through reduction of oxidative stress and inhibition of ethylene signaling pathway. PMID:28662156

Hydrogen sulfide alleviates postharvest ripening and senescence of banana by antagonizing the effect of ethylene.

PubMed

Ge, Yun; Hu, Kang-Di; Wang, Sha-Sha; Hu, Lan-Ying; Chen, Xiao-Yan; Li, Yan-Hong; Yang, Ying; Yang, Feng; Zhang, Hua

2017-01-01

Accumulating evidence shows that hydrogen sulfide (H2S) acts as a multifunctional signaling molecule in plants, whereas the interaction between H2S and ethylene is still unclear. In the present study we investigated the role of H2S in ethylene-promoted banana ripening and senescence by the application of ethylene released from 1.0 g·L-1 ethephon solution or H2S with 1 mM sodium hydrosulfide (NaHS) as the donor or in combination. Fumigation with ethylene was found to accelerate banana ripening and H2S treatment effectively alleviated ethylene-induced banana peel yellowing and fruit softening in parallel with decreased activity of polygalacturonase (PG). Ethylene+H2S treatment also delayed the decreases in chlorophyll and total phenolics, and increased the accumulation of flavonoid, whereas decreased the contents of carotenoid, soluble protein in banana peel and reducing sugar in pulp compared with ethylene treatment alone. Besides, ethylene+H2S treatment suppressed the accumulation of superoxide radicals (·O2-), hydrogen peroxide (H2O2) and malondialdehyde (MDA) which accumulated highly in ethylene-treated banana peels. Furthermore H2S enhanced total antioxidant capacity in ethylene-treated banana peels with the 2,2'-azobis(3-ethylbenz-thiazoline-6-sulfonic acid (ABTS) assay. The result of quantitative real-time PCR showed that the combined treatment of ethylene with H2S down-regulated the expression of ethylene synthesis genes MaACS1, MaACS2 and MaACO1 and pectate lyase MaPL compared with ethylene treatment, while the expression of ethylene receptor genes MaETR, MaERS1 and MaERS2 was enhanced in combination treatment compared with ethylene alone. In all, it can be concluded that H2S alleviates banana fruit ripening and senescence by antagonizing the effect of ethylene through reduction of oxidative stress and inhibition of ethylene signaling pathway.

Membrane glycerolipid equilibrium under endoplasmic reticulum stress in Arabidopsis thaliana.

PubMed

Yu, Chao-Yuan; Nguyen, Van Cam; Chuang, Ling; Kanehara, Kazue

2018-06-02

Endoplasmic reticulum (ER) is an indispensable organelle for secretory protein synthesis as well as metabolism of phospholipids and their derivatives in eukaryotic cells. Various external and internal factors may cause an accumulation of aberrant proteins in the ER, which causes ER stress and activates cellular ER stress responses to cope with the stress. In animal research, molecular mechanisms for protein quality control upon ER stress are well documented; however, how cells maintain lipid homeostasis under ER stress is an emerging issue. The ratio of phosphatidylcholine (PC) to phosphatidylethanolamine (PE), two major phospholipid classes, is important under ER stress in animal cells. However, in seed plants, no study has reported on the changes in membrane lipid content under ER stress, although a number of physiologically important environmental stresses, such as heat and salinity, induce ER stress. Here, we investigated membrane glycerolipid metabolism under ER stress in Arabidopsis. ER stress transcriptionally affected PC and PE biosynthesis pathways differentially, with no significant changes in membrane glycerolipid content. Our results suggest that higher plants maintain membrane lipid equilibrium during active transcription of phospholipid biosynthetic genes under ER stress. Copyright © 2018 Elsevier Inc. All rights reserved.

Role of silent information regulator 1 in the protective effect of hydrogen sulfide on homocysteine-induced cognitive dysfunction: Involving reduction of hippocampal ER stress.

PubMed

Tang, Yi-Yun; Wang, Ai-Ping; Wei, Hai-Jun; Li, Man-Hong; Zou, Wei; Li, Xiang; Wang, Chun-Yan; Zhang, Ping; Tang, Xiao-Qing

2018-04-16

Homocysteine (Hcy) causes cognitive deficits and hippocampal endoplasmic reticulum (ER) stress. Our previous study has confirmed that Hydrogen sulfide (H 2 S) attenuates Hcy-induced cognitive dysfunction and hippocampal ER stress. Silent information regulator 1 (Sirt-1) is indispensable in the formation of learning and memory. Therefore, the aim of this study was to explore the role of Sirt-1 in the protective effect of H 2 S against Hcy-induced cognitive dysfunction. We found that NaHS (a donor of H 2 S) markedly up-regulated the expression of Sirt-1 in the hippocampus of Hcy-exposed rats. Sirtinol, a specific inhibitor of Sirt-1, reversed the improving role of NaHS in the cognitive function of Hcy-exposed rats, as evidenced by that sirtinol increased the escape latency and the swim distance in the acquisition trial of morris water maze (MWM) test, decreased the times crossed through and the time spent in the target quadrant in the probe trail of MWM test, and reduced the discrimination index in the novel object recognition test (NORT) in the rats cotreated with NaHS and Hcy. We also found that sirtinol reversed the protection of NaHS against Hcy-induced hippocampal ER-stress, as evidenced by up-regulating the expressions of GRP78, CHOP, and cleaved caspase-12 in the hippocampus of rats cotreated with NaHS and Hcy. These results suggested the contribution of upregulation of hippocampal Sirt-1 to the improving role of H 2 S in the cognitive function of Hcy-exposed rats, which involves suppression of hippocampal ER stress. Our finding provides a new insight into the mechanism underlying the inhibitory role of H 2 S in Hcy-induced cognitive dysfunction. Copyright © 2018 Elsevier B.V. All rights reserved.

Aggregation-prone c9FTD/ALS poly(GA) RAN-translated proteins cause neurotoxicity by inducing ER stress.

PubMed

Zhang, Yong-Jie; Jansen-West, Karen; Xu, Ya-Fei; Gendron, Tania F; Bieniek, Kevin F; Lin, Wen-Lang; Sasaguri, Hiroki; Caulfield, Thomas; Hubbard, Jaime; Daughrity, Lillian; Chew, Jeannie; Belzil, Veronique V; Prudencio, Mercedes; Stankowski, Jeannette N; Castanedes-Casey, Monica; Whitelaw, Ena; Ash, Peter E A; DeTure, Michael; Rademakers, Rosa; Boylan, Kevin B; Dickson, Dennis W; Petrucelli, Leonard

2014-10-01

The occurrence of repeat-associated non-ATG (RAN) translation, an atypical form of translation of expanded repeats that results in the synthesis of homopolymeric expansion proteins, is becoming more widely appreciated among microsatellite expansion disorders. Such disorders include amyotrophic lateral sclerosis and frontotemporal dementia caused by a hexanucleotide repeat expansion in the C9ORF72 gene (c9FTD/ALS). We and others have recently shown that this bidirectionally transcribed repeat is RAN translated, and the "c9RAN proteins" thusly produced form neuronal inclusions throughout the central nervous system of c9FTD/ALS patients. Nonetheless, the potential contribution of c9RAN proteins to disease pathogenesis remains poorly understood. In the present study, we demonstrate that poly(GA) c9RAN proteins are neurotoxic and may be implicated in the neurodegenerative processes of c9FTD/ALS. Specifically, we show that expression of poly(GA) proteins in cultured cells and primary neurons leads to the formation of soluble and insoluble high molecular weight species, as well as inclusions composed of filaments similar to those observed in c9FTD/ALS brain tissues. The expression of poly(GA) proteins is accompanied by caspase-3 activation, impaired neurite outgrowth, inhibition of proteasome activity, and evidence of endoplasmic reticulum (ER) stress. Of importance, ER stress inhibitors, salubrinal and TUDCA, provide protection against poly(GA)-induced toxicity. Taken together, our data provide compelling evidence towards establishing RAN translation as a pathogenic mechanism of c9FTD/ALS, and suggest that targeting the ER using small molecules may be a promising therapeutic approach for these devastating diseases.

The Chemical Chaperone, PBA, Reduces ER Stress and Autophagy and Increases Collagen IV α5 Expression in Cultured Fibroblasts From Men With X-Linked Alport Syndrome and Missense Mutations.

PubMed

Wang, Dongmao; Mohammad, Mardhiah; Wang, Yanyan; Tan, Rachel; Murray, Lydia S; Ricardo, Sharon; Dagher, Hayat; van Agtmael, Tom; Savige, Judy

2017-07-01

X-linked Alport syndrome (OMIM 301050) is caused by COL4A5 missense variants in 40% of families. This study examined the effects of chemical chaperone treatment (sodium 4-phenylbutyrate) on fibroblast cell lines derived from men with missense mutations. Dermal fibroblast cultures were established from 2 affected men and 3 normals. Proliferation rates were examined, the collagen IV α5 chain localized with immunostaining, and levels of the intra- and extracellular chains quantitated with an in-house enzyme-linked immunosorbent assay. COL4A5 mRNA was measured using quantitative reverse transcriptase polymerase chain reaction. Endoplasmic reticulum (ER) size was measured on electron micrographs and after HSP47 immunostaining. Markers of ER stress (ATF6, HSPA5, DDIT3), autophagy (ATG5, BECN1, ATG7), and apoptosis (CASP3, BAD, BCL 2 ) were also quantitated by quantitative reverse transcriptase polymerase chain reaction. Measurements were repeated after 48 hours of incubation with 10 mM sodium 4-phenylbutyrate acid. Both COL4A5 missense variants were associated with reduced proliferation rates on day 6 ( P  = 0.01 and P  = 0.03), ER enlargement, and increased mRNA for ER stress and autophagy (all P values < 0.05) when compared with normal. Sodium 4-phenylbutyrate treatment increased COL4A5 transcript levels ( P  < 0.01), and reduced ER size ( P  < 0.01 by EM and P  < 0.001 by immunostaining), ER stress (p HSPA5 and DDIT3, all P values < 0.01) and autophagy (ATG7, P  < 0.01). Extracellular collagen IV α5 chain was increased in the M1 line only ( P  = 0.06). Sodium 4-phenylbutyrate increases collagen IV α5 mRNA levels, reduces ER stress and autophagy, and possibly facilitates collagen IV α5 extracellular transport. Whether these actions delay end-stage renal failure in men with X-linked Alport syndrome and missense mutations will only be determined with clinical trials.

Alleviating Parenting Stress in Parents with Intellectual Disabilities: A Randomized Controlled Trial of a Video-feedback Intervention to Promote Positive Parenting.

PubMed

Hodes, Marja W; Meppelder, Marieke; de Moor, Marleen; Kef, Sabina; Schuengel, Carlo

2017-05-01

Adapted parenting support may alleviate the high levels of parenting stress experienced by many parents with intellectual disabilities. Parents with mild intellectual disabilities or borderline intellectual functioning were randomized to experimental (n = 43) and control (n = 42) conditions. Parents in both groups received care-as-usual. The experimental group also received an adapted version of video-feedback intervention for positive parenting and learning difficulties (VIPP-LD). Measures of parenting stress were obtained pre-test, post-test and 3-month follow-up. Randomization to the experimental group led to a steeper decline in parenting stress related to the child compared to the control group (d = 0.46). No statistically significant effect on stress related to the parent's own functioning or situation was found. The results of the study suggest the feasibility of reducing parenting stress in parents with mild intellectual disability (MID) through parenting support, to the possible benefit of their children. © 2016 John Wiley & Sons Ltd.

Executive Well-Being: Stress and Administrators.

ERIC Educational Resources Information Center

Giammatteo, Michael C.; Giammatteo, Dolores M.

This booklet explains the meaning and sources of stress, presents a model differentiating among several approaches to dealing with stress, and offers advice and self-help exercises to aid in alleviating the causes of stress. Each chapter topic is a component of the stress alleviation model: stress awareness, tolerance, stress reduction, and stress…

Lack of TXNIP protects against mitochondria-mediated apoptosis but not against fatty acid-induced ER stress-mediated beta-cell death.

PubMed

Chen, Junqin; Fontes, Ghislaine; Saxena, Geetu; Poitout, Vincent; Shalev, Anath

2010-02-01

We have previously shown that lack of thioredoxin-interacting protein (TXNIP) protects against diabetes and glucotoxicity-induced beta-cell apoptosis. Because the role of TXNIP in lipotoxicity is unknown, the goal of the present study was to determine whether TXNIP expression is regulated by fatty acids and whether TXNIP deficiency also protects beta-cells against lipoapoptosis. RESARCH DESIGN AND METHODS: To determine the effects of fatty acids on beta-cell TXNIP expression, INS-1 cells and isolated islets were incubated with/without palmitate and rats underwent cyclic infusions of glucose and/or Intralipid prior to islet isolation and analysis by quantitative real-time RT-PCR and immunoblotting. Using primary wild-type and TXNIP-deficient islets, we then assessed the effects of palmitate on apoptosis (transferase-mediated dUTP nick-end labeling [TUNEL]), mitochondrial death pathway (cytochrome c release), and endoplasmic reticulum (ER) stress (binding protein [BiP], C/EBP homologous protein [CHOP]). Effects of TXNIP deficiency were also tested in the context of staurosporine (mitochondrial damage) or thapsigargin (ER stress). Glucose elicited a dramatic increase in islet TXNIP expression both in vitro and in vivo, whereas fatty acids had no such effect and, when combined with glucose, even abolished the glucose effect. We also found that TXNIP deficiency does not effectively protect against palmitate or thapsigargin-induced beta-cell apoptosis, but specifically prevents staurosporine- or glucose-induced toxicity. Our results demonstrate that unlike glucose, fatty acids do not induce beta-cell expression of proapoptotic TXNIP. They further reveal that TXNIP deficiency specifically inhibits the mitochondrial death pathway underlying beta-cell glucotoxicity, whereas it has very few protective effects against ER stress-mediated lipoapoptosis.

Endoplasmic reticulum stress in kidney function and disease.

PubMed

Taniguchi, Mai; Yoshida, Hiderou

2015-07-01

Recently, a number of papers have reported that endoplasmic reticulum (ER) stress is involved in the onset of various kidney diseases, but the pathological mechanisms responsible have not been clarified. In this review, we summarize recent findings on this issue and try to clarify the pathology of ER stress-induced kidney diseases. ER stress is evoked in various kidney diseases, including diabetic nephropathy, renal fibrosis, inflammation or osmolar contrast-induced renal injury, ischemia-reperfusion, genetic mutations of renal proteins, proteinuria and cyclosporine A treatment. In some cases, chemical chaperones, such as 4-phenylbutyrate and taurodeoxycholic acid, relieve the symptoms, indicating that ER stress-induced apoptosis of renal cells is one of the major causes of certain kidney diseases. Actually, the ER stress response provides protection against some kidney diseases, although the PERK-ATF4-CHOP pathway of the ER stress response is proapoptotic in some kidney diseases. The disposal of unfolded proteins by autophagy is also protective for some ER stress-induced kidney diseases. Because ER stress is a major cause of some kidney diseases, the ER stress response and autophagy, which deal with unfolded proteins that accumulate in the ER, are promising therapeutic targets in acute and chronic kidney diseases.

Treadmill exercise alleviates chronic mild stress-induced depression in rats.

PubMed

Lee, Taeck-Hyun; Kim, Kijeong; Shin, Mal-Soon; Kim, Chang-Ju; Lim, Baek-Vin

2015-12-01

Depression is a major cause of disability and one of the most common public health problems. In the present study, antidepressive effect of treadmill exercise on chronic mild stress (CMS)-induced depression in rats was investigated. For this, sucrose intake test, immunohistochemistry for 5-bromo-2'-deoxyuridine, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling staining, and Western blot analysis for brain-derived neurotrophic factor, cyclic adenosine monophosphate response element binding protein, and endothelial nitric oxide synthase were conducted. Following adaptation to the animal vivarium and two baseline fluid intake tests, the animals were divided into four groups: the control group, the CMS-induced depression group, the CMS-induced depression and exercise group, and the CMS-induced depression and fluoxetine-treated group. The animals in the CMS groups were exposed to the CMS conditions for 8 weeks and those in the control group were exposed to the control conditions for 8 weeks. After 4 weeks of CMS, the rats in the CMS-induced depression and exercise group were made to run on a motorized treadmill for 30 min once a day for 4 weeks. In the present results, treadmill exercise alleviated CMS-induced depressive symptoms. Treadmill exercise restored sucrose consumption, increased cell proliferation, and decreased apoptotic cell death. The present results suggest the possibility that exercise may improve symptoms of depression.

Apigenin Alleviates Endotoxin-Induced Myocardial Toxicity by Modulating Inflammation, Oxidative Stress, and Autophagy

PubMed Central

Li, Fang; Lang, Fangfang; Zhang, Huilin; Xu, Liangdong; Wang, Yidan; Zhai, Chunxiao

2017-01-01

Apigenin, a component in daily diets, demonstrates antioxidant and anti-inflammatory properties. Here, we intended to explore the mechanism of apigenin-mediated endotoxin-induced myocardial injury and its role in the interplay among inflammation, oxidative stress, and autophagy. In our lipopolysaccharide- (LPS-) induced myocardial injury model, apigenin ameliorated cardiac injury (lactate dehydrogenase (LDH) and creatine kinase (CK)), cell death (TUNEL staining, DNA fragmentation, and PARP activity), and tissue damage (cardiac troponin I (cTnI) and cardiac myosin light chain-1 (cMLC1)) and improved cardiac function (ejection fraction (EF) and end diastolic left ventricular inner dimension (LVID)). Apigenin also alleviated endotoxin-induced myocardial injury by modulating oxidative stress (nitrotyrosine and protein carbonyl) and inflammatory cytokines (TNF-α, IL-1β, MIP-1α, and MIP-2) along with their master regulator NFκB. Apigenin modulated redox homeostasis, and its anti-inflammatory role might be associated with its ability to control autophagy. Autophagy (determined by LAMP1, ATG5, and p62), its transcriptional regulator transcription factor EB (TFEB), and downstream target genes including vacuolar protein sorting-associated protein 11 (Vps11) and microtubule-associated proteins 1A/1B light chain 3B (Map1lc3) were modulated by apigenin. Thus, our study demonstrated that apigenin may lead to potential development of new target in sepsis treatment or other myocardial oxidative and/or inflammation-induced injuries. PMID:28828145

Apigenin Alleviates Endotoxin-Induced Myocardial Toxicity by Modulating Inflammation, Oxidative Stress, and Autophagy.

PubMed

Li, Fang; Lang, Fangfang; Zhang, Huilin; Xu, Liangdong; Wang, Yidan; Zhai, Chunxiao; Hao, Enkui

2017-01-01

Apigenin, a component in daily diets, demonstrates antioxidant and anti-inflammatory properties. Here, we intended to explore the mechanism of apigenin-mediated endotoxin-induced myocardial injury and its role in the interplay among inflammation, oxidative stress, and autophagy. In our lipopolysaccharide- (LPS-) induced myocardial injury model, apigenin ameliorated cardiac injury (lactate dehydrogenase (LDH) and creatine kinase (CK)), cell death (TUNEL staining, DNA fragmentation, and PARP activity), and tissue damage (cardiac troponin I (cTnI) and cardiac myosin light chain-1 (cMLC1)) and improved cardiac function (ejection fraction (EF) and end diastolic left ventricular inner dimension (LVID)). Apigenin also alleviated endotoxin-induced myocardial injury by modulating oxidative stress (nitrotyrosine and protein carbonyl) and inflammatory cytokines (TNF- α , IL-1 β , MIP-1 α , and MIP-2) along with their master regulator NF κ B. Apigenin modulated redox homeostasis, and its anti-inflammatory role might be associated with its ability to control autophagy. Autophagy (determined by LAMP1, ATG5, and p62), its transcriptional regulator transcription factor EB (TFEB), and downstream target genes including vacuolar protein sorting-associated protein 11 (Vps11) and microtubule-associated proteins 1A/1B light chain 3B (Map1lc3) were modulated by apigenin. Thus, our study demonstrated that apigenin may lead to potential development of new target in sepsis treatment or other myocardial oxidative and/or inflammation-induced injuries.

Multivesicular body formation enhancement and exosome release during endoplasmic reticulum stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kanemoto, Soshi; Nitani, Ryota; Murakami, Tatsuhiko

The endoplasmic reticulum (ER) plays a pivotal role in maintaining cellular homeostasis. However, numerous environmental and genetic factors give rise to ER stress by inducing an accumulation of unfolded proteins. Under ER stress conditions, cells initiate the unfolded protein response (UPR). Here, we demonstrate a novel aspect of the UPR by electron microscopy and immunostaining analyses, whereby multivesicular body (MVB) formation was enhanced after ER stress. This MVB formation was influenced by inhibition of ER stress transducers inositol required enzyme 1 (IRE1) and PKR-like ER kinase (PERK). Furthermore, exosome release was also increased during ER stress. However, in IRE1 ormore » PERK deficient cells, exosome release was not upregulated, indicating that IRE1- and PERK-mediated pathways are involved in ER stress-dependent exosome release. - Highlights: • Endoplasmic reticulum (ER) stress induces multivesicular body (MVB) formation. • ER stress transducers IRE1 and PERK mediate MVB formation. • Exosome release is enhanced after ER stress. • IRE1 or PERK deficiency blocks upregulation of ER stress-dependent exosome release.« less

Endoplasmic Reticulum Stress and Oxidative Stress in Cell Fate Decision and Human Disease

PubMed Central

Cao, Stewart Siyan

2014-01-01

Abstract Significance: The endoplasmic reticulum (ER) is a specialized organelle for the folding and trafficking of proteins, which is highly sensitive to changes in intracellular homeostasis and extracellular stimuli. Alterations in the protein-folding environment cause accumulation of misfolded proteins in the ER that profoundly affect a variety of cellular signaling processes, including reduction–oxidation (redox) homeostasis, energy production, inflammation, differentiation, and apoptosis. The unfolded protein response (UPR) is a collection of adaptive signaling pathways that evolved to resolve protein misfolding and restore an efficient protein-folding environment. Recent Advances: Production of reactive oxygen species (ROS) has been linked to ER stress and the UPR. ROS play a critical role in many cellular processes and can be produced in the cytosol and several organelles, including the ER and mitochondria. Studies suggest that altered redox homeostasis in the ER is sufficient to cause ER stress, which could, in turn, induce the production of ROS in the ER and mitochondria. Critical Issues: Although ER stress and oxidative stress coexist in many pathologic states, whether and how these stresses interact is unknown. It is also unclear how changes in the protein-folding environment in the ER cause oxidative stress. In addition, how ROS production and protein misfolding commit the cell to an apoptotic death and contribute to various degenerative diseases is unknown. Future Directions: A greater fundamental understanding of the mechanisms that preserve protein folding homeostasis and redox status will provide new information toward the development of novel therapeutics for many human diseases. Antioxid. Redox Signal. 21, 396–413. PMID:24702237

Kaempferol induces apoptosis in HepG2 cells via activation of the endoplasmic reticulum stress pathway.

PubMed

Guo, Haiqing; Ren, Feng; Zhang, Li; Zhang, Xiangying; Yang, Rongrong; Xie, Bangxiang; Li, Zhuo; Hu, Zhongjie; Duan, Zhongping; Zhang, Jing

2016-03-01

Kaempferol is a flavonoid compound that has gained importance due to its antitumor properties; however, the underlying mechanisms remain to be fully understood. The present study aimed to investigate the molecular mechanisms of the antitumor function of kaempferol in HepG2 hepatocellular carcinoma cells. Kaempferol was determined to reduce cell viability, increase lactate dehydrogenase activity and induce apoptosis in a concentration‑ and time‑dependent manner in HepG2 cells. Additionally, kaempferol‑induced apoptosis possibly acts via the endoplasmic reticulum (ER) stress pathway, due to the significant increase in the protein expression levels of glucose‑regulated protein 78, glucose‑regulated protein 94, protein kinase R‑like ER kinase, inositol‑requiring enzyme 1α, partial activating transcription factor 6 cleavage, caspase‑4, C/EBP homologous protein (CHOP) and cleaved caspase‑3. The pro‑apoptotic activity of kaempferol was determined to be due to induction of the ER stress‑CHOP pathway, as: i) ER stress was blocked by 4‑phenyl butyric acid (4‑PBA) pretreatment and knockdown of CHOP with small interfering RNA, which resulted in alleviation of kaempferol‑induced HepG2 cell apoptosis; and ii) transfection with plasmid overexpressing CHOP reversed the protective effect of 4‑PBA in kaempferol‑induced HepG2 cells and increased the apoptotic rate. Thus, kaempferol promoted HepG2 cell apoptosis via induction of the ER stress‑CHOP signaling pathway. These observations indicate that kaempferol may be used as a potential chemopreventive treatment strategy for patients with hepatocellular carcinoma.

5-Aminolevulinic Acid (ALA) Alleviated Salinity Stress in Cucumber Seedlings by Enhancing Chlorophyll Synthesis Pathway.

PubMed

Wu, Yue; Jin, Xin; Liao, Weibiao; Hu, Linli; Dawuda, Mohammed M; Zhao, Xingjie; Tang, Zhongqi; Gong, Tingyu; Yu, Jihua

2018-01-01

5-Aminolevulinic acid (ALA) is a common precursor of tetrapyrroles as well as a crucial growth regulator in higher plants. ALA has been proven to be effective in improving photosynthesis and alleviating the adverse effects of various abiotic stresses in higher plants. However, little is known about the mechanism of ALA in ameliorating the photosynthesis of plant under abiotic stress. In this paper, we studied the effects of exogenous ALA on salinity-induced damages of photosynthesis in cucumber ( Cucumis sativus L.) seedlings. We found that the morphology (plant height, leave area), light utilization capacity of PS II [qL, Y(II)] and gas exchange capacity (Pn, gs, Ci, and Tr) were significantly retarded under NaCl stress, but these parameters were all recovered by the foliar application of 25 mg L -1 ALA. Besides, salinity caused heme accumulation and up-regulation of gene expression of ferrochelatase ( HEMH ) with suppression of other genes involved in chlorophyll synthesis pathway. Exogenously application of ALA under salinity down-regulated the heme content and HEMH expression, but increased the gene expression levels of glutamyl-tRNA reductase ( HEMA1 ), Mg-chelatase ( CHLH ), and protochlorophyllide oxidoreductase ( POR ). Moreover, the contents of intermediates involved in chlorophyll branch were increased by ALA, including protoporphyrin IX (Proto IX), Mg-protoporphyrin IX (Mg-Proto IX, protochlorophyllide (Pchlide), and chlorophyll (Chl a and Chl b ) under salt stress. Ultrastructural observation of mesophyll cell showed that the damages of photosynthetic apparatus under salinity were fixed by ALA. Collectively, the chlorophyll biosynthesis pathway was enhanced by exogenous ALA to improve the tolerance of cucumber under salinity.

ERdj5 sensitizes neuroblastoma cells to endoplasmic reticulum stress-induced apoptosis.

PubMed

Thomas, Christophoros G; Spyrou, Giannis

2009-03-06

Down-regulation of the unfolded protein response (UPR) can be therapeutically valuable in cancer treatment, and endoplasmic reticulum (ER)-resident chaperone proteins may thus be targets for developing novel chemotherapeutic strategies. ERdj5 is a novel ER chaperone that regulates the ER-associated degradation of misfolded proteins through its associations with EDEM and the ER stress sensor BiP. To investigate whether ERdj5 can regulate ER stress signaling pathways, we exposed neuroblastoma cells overexpressing ERdj5 to ER stress inducers. ERdj5 promoted apoptosis in tunicamycin, thapsigargin, and bortezomib-treated cells. To provide further evidence that ERdj5 induces ER stress-regulated apoptosis, we targeted Bcl-2 to ER of ERdj5-overexpressing cells. Targeting the Bcl-2 to ER prevented the apoptosis induced by ER stress inducers but not by non-ER stress apoptotic stimuli, suggesting induction of ER stress-regulated apoptosis by ERdj5. ERdj5 enhanced apoptosis by abolishing the ER stress-induced phosphorylation of eukaryotic translation initiation factor 2alpha (eIF2alpha) and the subsequent translational repression. ERdj5 was found to inhibit the eIF2alpha phosphorylation under ER stress through inactivating the pancreatic endoplasmic reticulum kinase. The compromised integrated stress response observed in ERdj5-overexpressing ER-stressed cells due to repressed eIF2alpha phosphorylation correlated with impaired neuroblastoma cell resistance under ER stress. These results demonstrate that ERdj5 decreases neuroblastoma cell survival by down-regulating the UPR, raising the possibility that this protein could be a target for anti-tumor approaches.

Retinoic acid receptor-related orphan receptor α stimulates adipose tissue inflammation by modulating endoplasmic reticulum stress.

PubMed

Liu, Yin; Chen, Yulong; Zhang, Jinlong; Liu, Yulan; Zhang, Yanjie; Su, Zhiguang

2017-08-25

Adipose tissue inflammation has been linked to metabolic diseases such as obesity and type 2 diabetes. However, the molecules that mediate inflammation in adipose tissue have not been addressed. Although retinoic acid receptor-related orphan receptor α (RORα) is known to be involved in the regulation of inflammatory response in some tissues, its role is largely unknown in adipose tissue. Conversely, it is known that endoplasmic reticulum (ER) stress and unfolding protein response (UPR) signaling affect the inflammatory response in obese adipose tissue, but whether RORα regulates these processes remains unknown. In this study, we investigate the link between RORα and adipose tissue inflammation. We showed that the inflammatory response in macrophages or 3T3-L1 adipocytes stimulated by lipopolysaccharide, as well as adipose tissue in obese mice, markedly increased the expression of RORα. Adenovirus-mediated overexpression of RORα or treatment with the RORα-specific agonist SR1078 enhanced the expression of inflammatory cytokines and increased the number of infiltrated macrophages into adipose tissue. Furthermore, SR1078 up-regulated the mRNA expression of ER stress response genes and enhanced phosphorylations of two of the three mediators of major UPR signaling pathways, PERK and IRE1α. Finally, we found that alleviation of ER stress using a chemical chaperone followed by the suppression of RORα induced inflammation in adipose tissue. Our data suggest that RORα-induced ER stress response potentially contributes to the adipose tissue inflammation that can be mitigated by treatment with chemical chaperones. The relationships established here between RORα expression, inflammation, and UPR signaling may have implications for therapeutic targeting of obesity-related metabolic diseases. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Alleviation effect of arbutin on oxidative stress generated through tyrosinase reaction with l-tyrosine and l-DOPA

PubMed Central

2014-01-01

Background Hydroxyl radical that has the highest reactivity among reactive oxygen species (ROS) is generated through l-tyrosine-tyrosinase reaction. Thus, the melanogenesis might induce oxidative stress in the skin. Arbutin (p-hydroxyphenyl-β-d-glucopyranoside), a well-known tyrosinase inhibitor has been widely used for the purpose of skin whitening. The aim of the present study was to examine if arbutin could suppress the hydroxyl radical generation via tyrosinase reaction with its substrates, l-tyrosine and l-DOPA. Results The hydroxyl radical, which was determined by an electron spin resonance-spin trapping technique, was generated by the addition of not only l-tyrosine but l-DOPA to tyrosinase in a concentration dependent manner. Arbutin could inhibit the hydroxyl radical generation in the both reactions. Conclusion It is presumed that arbutin could alleviate oxidative stress derived from the melanogenic pathway in the skin in addition to its function as a whitening agent in cosmetics. PMID:25297374

Selenium Alleviates Oxidative Stress and Lung Damage Induced by Aluminum Chloride in Adult Rats: Biochemical and Histological Approach.

PubMed

Ghorbel, Imen; Elwej, Awatef; Chaabane, Mariem; Jamoussi, Kamel; Mnif, Hela; Boudawara, Tahia; Zeghal, Najiba

2017-03-01

Our study pertains to the potential ability of selenium, used as a nutritional supplement, to alleviate oxidative stress induced by aluminum chloride in the lung tissue. Rats have received during 21 days either aluminum chloride (AlCl 3 ) (400 ppm) via drinking water, AlCl 3 associated with Na 2 SeO 3 (0.5 mg/kg of diet), or only Na 2 SeO 3 . Exposure of rats to AlCl 3 induced lung oxidative stress with an increase of malondialdehyde, hydrogen peroxide, and protein carbonyls levels. An alteration of lactate dehydrogenase activities and antioxidant redox status, enzymatic (catalase, superoxide dismutase, and glutathione peroxidase), and non-enzymatic (non-protein thiols, glutathione, metallothionein, and vitamin C) was also observed. These biochemical modifications were substantiated by histopathological data showing alveolar edema, a large number of hemosiderin-laden macrophages, and emphysema. Se supplementation attenuated the levels of oxidative stress by restoring antioxidant state and improved lung histological damage. Our results revealed that Se, a trace element with antioxidant properties, was effective in preventing lung damage.

Dexmedetomidine alleviates anxiety-like behaviors and cognitive impairments in a rat model of post-traumatic stress disorder.

PubMed

Ji, Mu-Huo; Jia, Min; Zhang, Ming-Qiang; Liu, Wen-Xue; Xie, Zhong-Cong; Wang, Zhong-Yun; Yang, Jian-Jun

2014-10-03

Post-traumatic stress disorder (PTSD) is a psychiatric disease that has substantial health implications, including high rates of health morbidity and mortality, as well as increased health-related costs. Although many pharmacological agents have proven the effects on the development of PTSD, current pharmacotherapies typically only produce partial improvement of PTSD symptoms. Dexmedetomidine is a selective, short-acting α2-adrenoceptor agonist, which has anxiolytic, sedative, and analgesic effects. We therefore hypothesized that dexmedetomidine possesses the ability to prevent the development of PTSD and alleviate its symptoms. By using the rat model of PTSD induced by five electric foot shocks followed by three weekly exposures to situational reminders, we showed that the stressed rats displayed pronounced anxiety-like behaviors and cognitive impairments compared to the controls. Notably, repeated administration of 20μg/kg dexmedetomidine showed impaired fear conditioning memory, decreased anxiety-like behaviors, and improved spatial cognitive impairments compared to the vehicle-treated stressed rats. These data suggest that dexmedetomidine may exert preventive and protective effects against anxiety-like behaviors and cognitive impairments in the rats with PTSD after repeated administration. Copyright © 2014 Elsevier Inc. All rights reserved.

Smyd1 Facilitates Heart Development by Antagonizing Oxidative and ER Stress Responses

PubMed Central

Park, Chong Yon; Harriss, June; Pierce, Stephanie A.; Dekker, Joseph D.; Valenzuela, Nicolas; Srivastava, Deepak; Schwartz, Robert J.; Stewart, M. David; Tucker, Haley O.

2015-01-01

Smyd1/Bop is an evolutionary conserved histone methyltransferase previously shown by conventional knockout to be critical for embryonic heart development. To further explore the mechanism(s) in a cell autonomous context, we conditionally ablated Smyd1 in the first and second heart fields of mice using a knock-in (KI) Nkx2.5-cre driver. Robust deletion of floxed-Smyd1 in cardiomyocytes and the outflow tract (OFT) resulted in embryonic lethality at E9.5, truncation of the OFT and right ventricle, and additional defects consistent with impaired expansion and proliferation of the second heart field (SHF). Using a transgenic (Tg) Nkx2.5-cre driver previously shown to not delete in the SHF and OFT, early embryonic lethality was bypassed and both ventricular chambers were formed; however, reduced cardiomyocyte proliferation and other heart defects resulted in later embryonic death at E11.5-12.5. Proliferative impairment prior to both early and mid-gestational lethality was accompanied by dysregulation of transcripts critical for endoplasmic reticulum (ER) stress. Mid-gestational death was also associated with impairment of oxidative stress defense—a phenotype highly similar to the previously characterized knockout of the Smyd1-interacting transcription factor, skNAC. We describe a potential feedback mechanism in which the stress response factor Tribbles3/TRB3, when directly methylated by Smyd1, acts as a co-repressor of Smyd1-mediated transcription. Our findings suggest that Smyd1 is required for maintaining cardiomyocyte proliferation at minimally two different embryonic heart developmental stages, and its loss leads to linked stress responses that signal ensuing lethality. PMID:25803368

CCN1/CYR61 overexpression in hepatic stellate cells induces ER stress-related apoptosis.

PubMed

Borkham-Kamphorst, Erawan; Steffen, Bettina T; Van de Leur, Eddy; Haas, Ute; Tihaa, Lidia; Friedman, Scott L; Weiskirchen, Ralf

2016-01-01

CCN1/CYR61 is a matricellular protein of the CCN family, comprising six secreted proteins specifically associated with the extracellular matrix (ECM). CCN1 acts as an enhancer of the cutaneous wound healing process by preventing hypertrophic scar formation through induction of myofibroblast senescence. In liver fibrosis, the senescent cells are primarily derived from activated hepatic stellate cells (HSC) that initially proliferate in response to liver damage and are the major source of ECM. We investigate here the possible use of CCN1 as a senescence inducer to attenuate liver fibrogenesis by means of adenoviral gene transfer in primary HSC, myofibroblasts (MFB) and immortalized HSC lines (i.e. LX-2, CFSC-2G). Infection with Ad5-CMV-CCN1 induced large amounts of CCN1 protein in all these cells, resulting in an overload of the endoplasmic reticulum (ER) and in a compensatory unfolded protein response (UPR). The UPR resulted in upregulation of ER chaperones including BIP/Grp78, Grp94 and led to an activation of IRE1α as evidenced by spliced XBP1 mRNA with IRE1α-induced JNK phosphorylation. The UPR arm PERK and eIF2a was phosphorylated, combined with significant CHOP upregulation. Ad5-CMV-CCN1 induced HSC apoptosis that was evident by proteolytic cleavage of caspase-12, caspase-9 and the executor caspase-3 and positive TUNEL stain. Remarkably, Ad5-CMV-CCN1 effectively reduced collagen type I mRNA expression and protein. We conclude that the matricellular protein CCN1 gene transfer induces HSC apoptosis through ER stress and UPR. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Ascophyllum nodosum Seaweed Extract Alleviates Drought Stress in Arabidopsis by Affecting Photosynthetic Performance and Related Gene Expression.

PubMed

Santaniello, Antonietta; Scartazza, Andrea; Gresta, Francesco; Loreti, Elena; Biasone, Alessandro; Di Tommaso, Donatella; Piaggesi, Alberto; Perata, Pierdomenico

2017-01-01

Drought represents one of the most relevant abiotic stress affecting growth and yield of crop plants. In order to improve the agricultural productivity within the limited water and land resources, it is mandatory to increase crop yields in presence of unfavorable environmental stresses. The use of biostimulants, often containing seaweed extracts, represents one of the options for farmers willing to alleviate abiotic stress consequences on crops. In this work, we investigated the responses of Arabidopsis plants treated with an extract from the brown alga Ascophyllum nodosum (ANE), under drought stress conditions, demonstrating that ANE positively influences Arabidopsis survival. Pre-treatment with ANE induced a partial stomatal closure, associated with changes in the expression levels of genes involved in ABA-responsive and antioxidant system pathways. The pre-activation of these pathways results in a stronger ability of ANE-treated plants to maintain a better photosynthetic performance compared to untreated plants throughout the dehydration period, combined with a higher capacity to dissipate the excess of energy as heat in the reaction centers of photosystem II. Our results suggest that drought stressed plants treated with ANE are able to maintain a strong stomatal control and relatively higher values of both water use efficiency (WUE) and mesophyll conductance during the last phase of dehydration. Simultaneously, the activation of a pre-induced antioxidant defense system, in combination with a more efficient energy dissipation mechanism, prevents irreversible damages to the photosynthetic apparatus. In conclusion, pre-treatment with ANE is effective to acclimate plants to the incoming stress, promoting an increased WUE and dehydration tolerance.

Ascophyllum nodosum Seaweed Extract Alleviates Drought Stress in Arabidopsis by Affecting Photosynthetic Performance and Related Gene Expression

PubMed Central

Santaniello, Antonietta; Scartazza, Andrea; Gresta, Francesco; Loreti, Elena; Biasone, Alessandro; Di Tommaso, Donatella; Piaggesi, Alberto; Perata, Pierdomenico

2017-01-01

Drought represents one of the most relevant abiotic stress affecting growth and yield of crop plants. In order to improve the agricultural productivity within the limited water and land resources, it is mandatory to increase crop yields in presence of unfavorable environmental stresses. The use of biostimulants, often containing seaweed extracts, represents one of the options for farmers willing to alleviate abiotic stress consequences on crops. In this work, we investigated the responses of Arabidopsis plants treated with an extract from the brown alga Ascophyllum nodosum (ANE), under drought stress conditions, demonstrating that ANE positively influences Arabidopsis survival. Pre-treatment with ANE induced a partial stomatal closure, associated with changes in the expression levels of genes involved in ABA-responsive and antioxidant system pathways. The pre-activation of these pathways results in a stronger ability of ANE-treated plants to maintain a better photosynthetic performance compared to untreated plants throughout the dehydration period, combined with a higher capacity to dissipate the excess of energy as heat in the reaction centers of photosystem II. Our results suggest that drought stressed plants treated with ANE are able to maintain a strong stomatal control and relatively higher values of both water use efficiency (WUE) and mesophyll conductance during the last phase of dehydration. Simultaneously, the activation of a pre-induced antioxidant defense system, in combination with a more efficient energy dissipation mechanism, prevents irreversible damages to the photosynthetic apparatus. In conclusion, pre-treatment with ANE is effective to acclimate plants to the incoming stress, promoting an increased WUE and dehydration tolerance. PMID:28824691

Spermine alleviates drought stress in white clover with different resistance by influencing carbohydrate metabolism and dehydrins synthesis.

PubMed

Li, Zhou; Jing, Wen; Peng, Yan; Zhang, Xin Quan; Ma, Xiao; Huang, Lin Kai; Yan, Yan-Hong

2015-01-01

The objective of this research was to analyse whether ameliorating drought stress through exogenously applied spermine (Spm) was related to carbohydrate metabolism, dehydrins accumulation and the transcription of genes encoding dehydrins in two white clovers (drought-susceptible cv. 'Ladino' and drought-resistant cv. 'Haifa') under controlled drying conditions for 10 days. The results show that the application of Spm effectively alleviates negative effects caused by drought stress in both cultivars. Exogenous Spm led to accumulation of more water-soluble carbohydrates (WSC), sucrose, fructose and sorbitol in both cultivars under drought stress, and also significantly elevated glucose content in leaves of drought-resistant cv. 'Haifa', but had no effect on drought-susceptible cv. 'Ladino'. Accordingly, the key enzyme activities of sucrose and sorbitol metabolism changed along with the application of Spm under drought stress. Spm induced a significant increase in sucrose phosphate synthase (SPS) or sorbitol dehydrogenase (SDH) activity, but decrease in sucrose synthetase (SS) activity when two cultivars were subjected to drought. In addition, the improved accumulation of dehydrins induced by exogenous Spm coincided with three genes expression which was responsible for dehydrins synthesis. But Spm-induced transcript level of dehydrin genes increased earlier in cv. 'Ladino' than that in cv. 'Haifa'. Thus, these results suggest that ameliorating drought stress through exogenously applied Spm may be associated with increased carbohydrate accumulation and dehydrins synthesis. There are differences between drought-susceptible and -resistant white clover cultivars related to Spm regulation of WSC metabolism and dehydrins expression.

[Alleviation of salt stress during maize seed germination by presoaking with exogenous sugar].

PubMed

Zhao, Ying; Yang, Ke-jun; Li, Zuo-tong; Zhao, Chang-jiang; Xu, Jing-yu; Hu, Xue- wei; Shi, Xin-xin; Ma, Li-feng

2015-09-01

The maize variety Kenyu 6 was used to study the effects of exogenous glucose (Glc) and sucrose (Suc) on salt tolerance of maize seeds at germination stage under 150 mmol · L(-1) NaCl treatment. Results showed that under salt stress condition, 0.5 mmol · L(-1) exogenous Glc and Suc presoaking could promote seed germination and early seedling growth. Compared with the salt treatment, Glc presoaking increased the shoot length, radicle length and corresponding dry mass up to 1.5, 1.3, 2.1 and 1.8 times, and those of the Suc presoaking treatment increased up to 1.7, 1.3. 2.7 and 1.9 times, respectively. Exogenous Glc and Suc presoaking resulted in decreased levels of thiobarbituric acid reactive substances (TBARS) and hydrogen peroxide (H2O2) content of maize shoot under salt stress, which were lowered by 24.9% and 20.6% respectively. Exogenous Glc and Suc presoaking could increase the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione peroxidase (GPX), glutathione reductase (GR) and induce glucose-6-phosphate dehydrogenase (G6PDH) activity of maize shoot under salt stress. Compared with the salt treatment. Glc presoaking increased the activity of SOD, APX, GPX, GR and G6PDH by 66.2%, 62.9%, 32.0%, 38.5% and 50.5%, and those of the Suc presoaking increased by 67.5%, 59.8%, 30.0%, 38.5% and 50.4%, respectively. Glc and Suc presoaking also significantly increased the contents of ascorbic acid (ASA) and glutathione (GSH), ASA/DHA and GSH/GSSG. The G6PDH activity was found closely related with the strong antioxidation capacity induced by exogenous sugars. In addition, Glc and Suc presoaking enhanced K+/Na+ in maize shoot by 1.3 and 1.4 times of water soaking salt treatment, respectively. These results indicated that exogenous Glc and Suc presoaking could improve antioxidation capacity of maize seeds and maintain the in vivo K+/Na+ ion balance to alleviate the inhibitory effect of salt stress on maize seed germination.

Adaptation to hot climate and strategies to alleviate heat stress in livestock production.

PubMed

Renaudeau, D; Collin, A; Yahav, S; de Basilio, V; Gourdine, J L; Collier, R J

2012-05-01

Despite many challenges faced by animal producers, including environmental problems, diseases, economic pressure, and feed availability, it is still predicted that animal production in developing countries will continue to sustain the future growth of the world's meat production. In these areas, livestock performance is generally lower than those obtained in Western Europe and North America. Although many factors can be involved, climatic factors are among the first and crucial limiting factors of the development of animal production in warm regions. In addition, global warming will further accentuate heat stress-related problems. The objective of this paper was to review the effective strategies to alleviate heat stress in the context of tropical livestock production systems. These strategies can be classified into three groups: those increasing feed intake or decreasing metabolic heat production, those enhancing heat-loss capacities, and those involving genetic selection for heat tolerance. Under heat stress, improved production should be possible through modifications of diet composition that either promotes a higher intake or compensates the low feed consumption. In addition, altering feeding management such as a change in feeding time and/or frequency, are efficient tools to avoid excessive heat load and improve survival rate, especially in poultry. Methods to enhance heat exchange between the environment and the animal and those changing the environment to prevent or limit heat stress can be used to improve performance under hot climatic conditions. Although differences in thermal tolerance exist between livestock species (ruminants > monogastrics), there are also large differences between breeds of a species and within each breed. Consequently, the opportunity may exist to improve thermal tolerance of the animals using genetic tools. However, further research is required to quantify the genetic antagonism between adaptation and production traits to evaluate

Induction of endoplasmic reticulum stress under endotoxin tolerance increases inflammatory responses and decreases Pseudomonas aeruginosa pneumonia.

PubMed

Kim, Sena; Joe, Yeonsoo; Park, Se-Ung; Jeong, Sun Oh; Kim, Jin-Kyung; Park, Seong Hoon; Pae, Hyun-Ock; Surh, Young-Joon; Shin, Jaekyoon; Chung, Hun Taeg

2018-06-20

Endotoxin tolerance develops in the late phase of sepsis to protect cells from an early hyperinflammatory response. Nonetheless, because it induces an immunosuppressive environment, patients with sepsis in its late phase are affected by secondary infections, particularly bacterial pneumonia. Here, we showed that induction of endoplasmic reticulum (ER) stress leads to activation of glycogen synthase kinase 3β (GSK-3β) and X-box-binding protein 1 (XBP-1) in an inositol-requiring enzyme 1α (IRE1α)-mediated manner, which in turn restores the inflammatory response in endotoxin-tolerant macrophages. Animal and in vitro models of endotoxin tolerance were studied along with a model of LPS-induced endotoxin tolerance and a model of cecal ligation and puncture (CLP)-induced endotoxin tolerance. To detect the suppressed inflammatory response during endotoxin tolerance, inflammatory-cytokine expression levels were measured by quantitative real-time PCR and an ELISA. Our research revealed that induction of ER stress alleviated lung injury in a septic host infected with Pseudomonas aeruginosa via the activation of GSK-3β and XBP-1 in an IRE1α-mediated manner. Consequently, in the lungs of the septic host infected with P. aeruginosa, symptoms of pneumonia improved and the infecting bacteria were cleared. Thus, for septic patients, determination of immune status may guide the selection of appropriate immunomodulation, and ER stress can be a novel therapeutic strategy restoring the immune response in patients with endotoxin tolerance. ©2018 Society for Leukocyte Biology.

Palmitate induces cisternal ER expansion via the activation of XBP-1/CCTα-mediated phospholipid accumulation in RAW 264.7 cells.

PubMed

Kim, Seong Keun; Oh, Eunhye; Yun, Mihee; Lee, Seong-Beom; Chae, Gue Tae

2015-07-16

Endoplasmic reticulum (ER) stress induces ER expansion. The expansion of the intracisternal space of the ER was found in macrophages associated with human atherosclerotic lesions. We also previously reported that palmitate induces cisternal ER expansion and necrosis in RAW 264.7 cells. In this study, we report on an investigation of the likely mechanism responsible for this palmitate-induced cisternal ER expansion in a mouse macrophage cell line, RAW 264.7 cells. RAW 264.7 cells were pre-treated with the designated inhibitor or siRNA, followed by treatment with palmitate. Changes in the ER structure were examined by transmission electron microscopy. The induction of ER stress was confirmed by an increase in the extent of phosphorylation of PERK, the expression of BiP and CHOP, and the splicing of XBP-1 mRNA. Phospholipid staining was performed with the LipidTOX Red phospholipidosis detection reagent. Related gene expressions were detected by quantitative real time-RT-PCR or RT-PCR. Palmitate was found to induce ER stress and cisternal ER expansion. In addition, palmitate-induced cisternal ER expansion was attenuated by ER stress inhibitors, such as 4-phenylbutyric acid (4-PBA) and tauroursodeoxycholic acid (TUDCA). The findings also show that palmitate induced-mRNA expression of CCTα, which increases phospholipid synthesis, was attenuated by the down-regulation of XBP-1, a part of ER stress. Furthermore, palmitate-induced phospholipid accumulation and cisternal ER expansion were attenuated by the down-regulation of XBP-1 or CCTα. The findings reported herein indicate that palmitate-induced cisternal ER expansion is dependent on the activation of XBP-1/CCTα-mediated phospholipid accumulation in RAW 264.7 cells.

Clinical and Pathological Significance of ER Stress Marker (BiP/GRP78 and PERK) Expression in Malignant Melanoma.

PubMed

Shimizu, Akira; Kaira, Kyoichi; Yasuda, Masahito; Asao, Takayuki; Ishikawa, Osamu

2017-01-01

Glucose-regulated protein of 78 kD (GRP78) also referred to as immunoglobulin heavy chain binding protein (BiP/GRP78) plays an important role in the endoplasmic reticulum (ER) stress. The level of BiP/GRP78 is highly elevated in various human cancers. The purpose of this study is to examine the prognostic significance of BiP/GRP78 expression in patients with malignant melanoma. A total of 133 malignant melanoma patients were analyzed, and tumor specimens were stained by immunohistochemistry for BiP/GRP78, PKR-like endoplasmic reticulum kinase (PERK), Ki-67, p53 and microvessel density (MVD) determined by CD34. BiP/GRP78 and PERK were highly expressed in 40 % (53/133) and 78 % (104/133), respectively. BiP/GRP78 disclosed a significant relationship with PERK expression, thickness, T factor, N factor, disease staging, cell proliferation (Ki-67) and MVD (CD34). By multivariate analysis, the high expression of BiP/GRP78 was identified as an independent prognostic factor for predicting poor survival against malignant melanoma. The increased BiP/GRP78 expression was clarified as an independent prognostic marker for predicting worse outcome. ER stress marker, BiP/GRP78 could be a powerful molecular target for the treatment of malignant melanoma.

XBP1-LOX Axis is critical in ER stress-induced growth of lung adenocarcinoma in 3D culture.

PubMed

Yang, Yi; Cheng, Bai-Jun; Jian, Hong; Chen, Zhi-Wei; Zhao, Yi; Yu, Yong-Feng; Li, Zi-Ming; Liao, Mei-Lin; Lu, Shun

2017-01-01

Rapid growth of tumor cells needs to consume large amounts of oxygen and glucose, due to lack of blood supply within the tumor, cells live in an environment that lack of oxygen and nutrients. This environment results in endoplasmic reticulum (ER) stress and activates the UPR (unfolded protein response). More and more evidence suggests UPR provides a growth signal pathway required for tumor growth. In the present study, we investigated the relationship between XBP1, one transcription factor in UPR, and the expression of LOX. We found that ER stress induces high expression of XBP1, one transcription factor in UPR, in both 2D culture and 3D culture; but only promotes growth of lung adenocarcinoma cells in in vitro 3D culture other than 2D culture. In 3D culture, we further showed that knockdown XBP1 expression can block Tm/Tg-induced cell growth. LOX genes may be key downstream effector of XBP1. Knockdown LOX expression can partially block XBP1-induced cell growth. Then we showed XBP1 suppressed by RNA interference (RNAi) can reduce the expression of LOX. For the first time, it is being shown that XBP1 can regulate the expression of LOX to promote cell growth.

Polyhydroxyfullerene Binds Cadmium Ions and Alleviates Metal-Induced Oxidative Stress in Saccharomyces cerevisiae

PubMed Central

Pradhan, Arunava; Pinheiro, José Paulo; Seena, Sahadevan; Pascoal, Cláudia

2014-01-01

The water-soluble polyhydroxyfullerene (PHF) is a functionalized carbon nanomaterial with several industrial and commercial applications. There have been controversial reports on the toxicity and/or antioxidant properties of fullerenes and their derivatives. Conversely, metals have been recognized as toxic mainly due to their ability to induce oxidative stress in living organisms. We investigated the interactive effects of PHF and cadmium ions (Cd) on the model yeast Saccharomyces cerevisiae by exposing cells to Cd (≤5 mg liter−1) in the absence or presence of PHF (≤500 mg liter−1) at different pHs (5.8 to 6.8). In the absence of Cd, PHF stimulated yeast growth up to 10.4%. Cd inhibited growth up to 79.7%, induced intracellular accumulation of reactive oxygen species (ROS), and promoted plasma membrane disruption in a dose- and pH-dependent manner. The negative effects of Cd on growth were attenuated by the presence of PHF, and maximum growth recovery (53.8%) was obtained at the highest PHF concentration and pH. The coexposure to Cd and PHF decreased ROS accumulation up to 36.7% and membrane disruption up to 30.7% in a dose- and pH-dependent manner. Two mechanisms helped to explain the role of PHF in alleviating Cd toxicity to yeasts: PHF decreased Cd-induced oxidative stress and bound significant amounts of Cd in the extracellular medium, reducing its bioavailability to the cells. PMID:25038095

Fibroblast growth factor 21 participates in adaptation to endoplasmic reticulum stress and attenuates obesity-induced hepatic metabolic stress.

PubMed

Kim, Seong Hun; Kim, Kook Hwan; Kim, Hyoung-Kyu; Kim, Mi-Jeong; Back, Sung Hoon; Konishi, Morichika; Itoh, Nobuyuki; Lee, Myung-Shik

2015-04-01

Fibroblast growth factor 21 (FGF21) is an endocrine hormone that exhibits anti-diabetic and anti-obesity activity. FGF21 expression is increased in patients with and mouse models of obesity or nonalcoholic fatty liver disease (NAFLD). However, the functional role and molecular mechanism of FGF21 induction in obesity or NAFLD are not clear. As endoplasmic reticulum (ER) stress is triggered in obesity and NAFLD, we investigated whether ER stress affects FGF21 expression or whether FGF21 induction acts as a mechanism of the unfolded protein response (UPR) adaptation to ER stress induced by chemical stressors or obesity. Hepatocytes or mouse embryonic fibroblasts deficient in UPR signalling pathways and liver-specific eIF2α mutant mice were employed to investigate the in vitro and in vivo effects of ER stress on FGF21 expression, respectively. The in vivo importance of FGF21 induction by ER stress and obesity was determined using inducible Fgf21-transgenic mice and Fgf21-null mice with or without leptin deficiency. We found that ER stressors induced FGF21 expression, which was dependent on a PKR-like ER kinase-eukaryotic translation factor 2α-activating transcription factor 4 pathway both in vitro and in vivo. Fgf21-null mice exhibited increased expression of ER stress marker genes and augmented hepatic lipid accumulation after tunicamycin treatment. However, these changes were attenuated in inducible Fgf21-transgenic mice. We also observed that Fgf21-null mice with leptin deficiency displayed increased hepatic ER stress response and liver injury, accompanied by deteriorated metabolic variables. Our results suggest that FGF21 plays an important role in the adaptive response to ER stress- or obesity-induced hepatic metabolic stress.

Alleviating effects of calcium on cobalt toxicity in two barley genotypes differing in cobalt tolerance.

PubMed

Lwalaba, Jonas Lwalaba Wa; Zvobgo, Gerald; Fu, Liangbo; Zhang, Xuelei; Mwamba, Theodore Mulembo; Muhammad, Noor; Mundende, Robert Prince Mukobo; Zhang, Guoping

2017-05-01

Cobalt (Co) contamination in soils is becoming a severe issue in environment safety and crop production. Calcium (Ca) , as a macro-nutrient element, shows the antagonism with many divalent heavy metals and the capacity of alleviating oxidative stress in plants. In this study, the protective role of Ca in alleviating Co stress was hydroponically investigated using two barley genotypes differing in Co toxicity tolerance. Barley seedlings exposed to 100µM Co showed the significant reduction in growth and photosynthetic rate, and the dramatic increase in the contents of reactive oxygen species (ROS), malondialdehyde (MDA), reduced glutathione (GSH) and oxidized glutathione (GSSG), and the activities of anti-oxidative enzymes, with Ea52 (Co-sensitive) being much more affected than Yan66 (Co-tolerant). Addition of Ca in growth medium alleviated Co toxicity by reducing Co uptake and enhancing the antioxidant capacity. The effect of Ca in alleviating Co toxicity was much greater in Yan66 than in Ea52. The results indicate that the alleviation of Co toxicity in barley plants by Ca is attributed to the reduced Co uptake and enhanced antioxidant capacity. Copyright © 2017 Elsevier Inc. All rights reserved.

Alleviation of salt stress by enterobacter sp. EJ01 in tomato and Arabidopsis is accompanied by up-regulation of conserved salinity responsive factors in plants.

PubMed

Kim, Kangmin; Jang, Ye-Jin; Lee, Sang-Myeong; Oh, Byung-Taek; Chae, Jong-Chan; Lee, Kui-Jae

2014-02-01

Microbiota in the niches of the rhizosphere zones can affect plant growth and responses to environmental stress conditions via mutualistic interactions with host plants. Specifically, some beneficial bacteria, collectively referred to as Plant Growth Promoting Rhizobacteria (PGPRs), increase plant biomass and innate immunity potential. Here, we report that Enterobacter sp. EJ01, a bacterium isolated from sea china pink (Dianthus japonicus thunb) in reclaimed land of Gyehwa-do in Korea, improved the vegetative growth and alleviated salt stress in tomato and Arabidopsis. EJ01 was capable of producing 1-aminocy-clopropane-1-carboxylate (ACC) deaminase and also exhibited indole-3-acetic acid (IAA) production. The isolate EJ01 conferred increases in fresh weight, dry weight, and plant height of tomato and Arabidopsis under both normal and high salinity conditions. At the molecular level, short-term treatment with EJ01 increased the expression of salt stress responsive genes such as DREB2b, RD29A, RD29B, and RAB18 in Arabidopsis. The expression of proline biosynthetic genes (i.e. P5CS1 and P5CS2) and of genes related to priming processes (i.e. MPK3 and MPK6) were also up-regulated. In addition, reactive oxygen species scavenging activities were enhanced in tomatoes treated with EJ01 in stressed conditions. GFP-tagged EJ01 displayed colonization in the rhizosphere and endosphere in the roots of Arabidopsis. In conclusion, the newly isolated Enterobacter sp. EJ01 is a likely PGPR and alleviates salt stress in host plants through multiple mechanisms, including the rapid up-regulation of conserved plant salt stress responsive signaling pathways.

Alleviation of Salt Stress by Enterobacter sp. EJ01 in Tomato and Arabidopsis Is Accompanied by Up-Regulation of Conserved Salinity Responsive Factors in Plants

PubMed Central

Kim, Kangmin; Jang, Ye-Jin; Lee, Sang-Myeong; Oh, Byung-Taek; Chae, Jong-Chan; Lee, Kui-Jae

2014-01-01

Microbiota in the niches of the rhizosphere zones can affect plant growth and responses to environmental stress conditions via mutualistic interactions with host plants. Specifically, some beneficial bacteria, collectively referred to as Plant Growth Promoting Rhizobacteria (PGPRs), increase plant biomass and innate immunity potential. Here, we report that Enterobacter sp. EJ01, a bacterium isolated from sea china pink (Dianthus japonicus thunb) in reclaimed land of Gyehwa-do in Korea, improved the vegetative growth and alleviated salt stress in tomato and Arabidopsis. EJ01 was capable of producing 1-aminocy-clopropane-1-carboxylate (ACC) deaminase and also exhibited indole-3-acetic acid (IAA) production. The isolate EJ01 conferred increases in fresh weight, dry weight, and plant height of tomato and Arabidopsis under both normal and high salinity conditions. At the molecular level, short-term treatment with EJ01 increased the expression of salt stress responsive genes such as DREB2b, RD29A, RD29B, and RAB18 in Arabidopsis. The expression of proline biosynthetic genes (i.e. P5CS1 and P5CS2) and of genes related to priming processes (i.e. MPK3 and MPK6) were also up-regulated. In addition, reactive oxygen species scavenging activities were enhanced in tomatoes treated with EJ01 in stressed conditions. GFP-tagged EJ01 displayed colonization in the rhizosphere and endosphere in the roots of Arabidopsis. In conclusion, the newly isolated Enterobacter sp. EJ01 is a likely PGPR and alleviates salt stress in host plants through multiple mechanisms, including the rapid up-regulation of conserved plant salt stress responsive signaling pathways. PMID:24598995

Selenium alleviates cadmium toxicity by preventing oxidative stress in sunflower (Helianthus annuus) seedlings.

PubMed

Saidi, Issam; Chtourou, Yacine; Djebali, Wahbi

2014-03-01

The present study investigated the possible mediatory role of selenium (Se) in protecting plants from cadmium (Cd) toxicity. The exposure of sunflower seedlings to 20μM Cd inhibited biomass production, decreased chlorophyll and carotenoid concentrations and strongly increased accumulation of Cd in both roots and shoots. Similarly, Cd enhanced hydrogen peroxides content and lipid peroxidation as indicated by malondialdehyde accumulation. Pre-soaking seeds with Se (5, 10 and 20μM) alleviated the negative effect of Cd on growth and led to a decrease in oxidative injuries caused by Cd. Furthermore, Se enhanced the activities of catalase, ascorbate peroxidase and glutathione reductase, but lowered that of superoxide dismutase and guaiacol peroxidase. As important antioxidants, ascorbate and glutathione contents in sunflower leaves exposed to Cd were significantly decreased by Se treatment. The data suggest that the beneficial effect of Se during an earlier growth period could be related to avoidance of cumulative damage upon exposure to Cd, thus reducing the negative consequences of oxidative stress caused by heavy metal toxicity. Copyright © 2013 Elsevier GmbH. All rights reserved.

Omega-3 and omega-6 fatty acids suppress ER- and oxidative stress in cultured neurons and neuronal progenitor cells from mice lacking PPT1.

PubMed

Kim, Sung-Jo; Zhang, Zhongjian; Saha, Arjun; Sarkar, Chinmoy; Zhao, Zhenwen; Xu, Yan; Mukherjee, Anil B

2010-08-02

Reactive oxygen species (ROS) damage brain lipids, carbohydrates, proteins, as well as DNA and may contribute to neurodegeneration. We previously reported that ER- and oxidative stress cause neuronal apoptosis in infantile neuronal ceroid lipofuscinosis (INCL), a lethal neurodegenerative storage disease, caused by palmitoyl-protein thioesterase-1 (PPT1) deficiency. Polyunsaturated fatty acids (PUFA) are essential components of cell membrane phospholipids in the brain and excessive ROS may cause oxidative damage of PUFA leading to neuronal death. Using cultured neurons and neuroprogenitor cells from mice lacking Ppt1, which mimic INCL, we demonstrate that Ppt1-deficient neurons and neuroprogenitor cells contain high levels of ROS, which may cause peroxidation of PUFA and render them incapable of providing protection against oxidative stress. We tested whether treatment of these cells with omega-3 or omega-6 PUFA protects the neurons and neuroprogenitor cells from oxidative stress and suppress apoptosis. We report here that both omega-3 and omega-6 fatty acids protect the Ppt1-deficient cells from ER- as well as oxidative stress and suppress apoptosis. Our results suggest that PUFA supplementation may have neuroprotective effects in INCL. Published by Elsevier Ireland Ltd.

Coadministration of VDR and RXR agonists synergistically alleviates atherosclerosis through inhibition of oxidative stress: An in vivo and in vitro study.

PubMed

Lin, L M; Peng, F; Liu, Y P; Chai, D J; Ning, R B; Xu, C S; Lin, J X

2016-08-01

Diabetes contributes to atherosclerosis partially through induction of oxidative stress. Both vitamin D receptor (VDR) and retinoid X receptor (RXR) agonists exhibit anti-atherogenic effects. We explored the effects of combination treatment with VDR and RXR agonists (represented by calcitriol and bexarotene, respectively) on atherosclerosis progression and the mechanisms involved, using a diabetes model of mice. The animals were intragastrically fed calcitriol (200 ng/kg, twice-a-week), bexarotene (10 mg/kg, once-daily) either alone or in combination for 12 weeks. VDR and RXR agonists delayed atherosclerosis progression independent of serum lipid and glucose levels, and significantly reduced the protein expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit gp91phox and nuclear factor-kappa B (NF-κB) subunit p65, as well as plasma biomarkers of oxidative stress and inflammation. Combination therapy alleviated atherosclerosis and inhibited indexes of oxidative stress and inflammation to a greater extent than either monotherapy. In the in vitro study, naturally occurring VDR ligand 1α,25-dihydroxyvitamin D3 (1,25[OH]2D3) and RXR ligand 9-cis retinoic acid (9-cis-RA), both significantly inhibited high-glucose-induced endothelial cell apoptosis. Co-administration of VDR and RXR ligands produced synergistic protection against endothelial apoptosis by antagonizing the protein kinase C /NADPH oxidase/reactive oxygen species pathway. The inhibitory effects of 9-cis-RA on oxidative stress was attenuated when VDR was downregulated by VDR siRNA; however, downregulation of RXR by RXR siRNA imposed no influence on the effects of 1,25(OH)2D3. Combination treatment with VDR and RXR agonists synergistically alleviated diabetic atherosclerosis through inhibition of oxidative stress, and the preventive effects of RXR agonist may partially depend on VDR activation. Copyright © 2016. Published by Elsevier Ireland Ltd.

Spontaneous nonalcoholic fatty liver disease and ER stress in Sidt2 deficiency mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Jialin; Anhui Province Key Laboratory of Biological Macro-molecules Research, Wannan Medical College, Wuhu, 241001; Zhang, Yao

Sidt2 is a newly discovered lysosomal membrane protein that is closely related to glucose metabolism. In the present study, we found that Sidt2 is also closely related to lipid metabolism. Gradual increases in serum triglyceride (TG) and free fatty acid, as well as elevated aspartate transaminase and alanine transaminase levels were observed in Sidt2{sup −/−} mice fed a normal diet from the age of 3 months, suggesting the presence of lipid metabolism disorders and impaired liver function in these mice. In the liver slices of 6-month-old Sidt2{sup −/−} mice, there were obvious fat degeneration and inflammatory changes. Almost all ofmore » the liver cells demonstrated different levels of lipid droplet accumulation and cell swelling, and some of the cells demonstrated balloon-like changes. Infiltration of inflammatory cells was observed in the portal area and hepatic lobule. Electron microscopy showed that macrophages tended to be attached to the endothelial cells, and a large number of lipid droplets were present in the liver cells. Oil red O staining showed that there were significantly increased number of deep straining particles in the liver cells of Sidt2{sup −/−} mice, and the TG content in liver tissue was also significantly increased. Detection of key genes and proteins related to fat synthesis showed that mRNA and protein levels of the SREBP1c in the liver of Sidt2{sup −/−} mice were significantly elevated, and the downstream genes acetyl-CoA carboxylase, fatty acid synthase, and mitochondrial glycerol 3-phosphate acyltransferase were significantly upregulated. In addition, there was severe endoplasmic reticulum stress (ERS) in the liver of Sidt2{sup −/−} mice, which had significantly increased levels of markers specific for unfolded protein response activation, Grp78 and CHOP, as well as significant elevation of downstream p-PERK, p-eIF2a, p-IRE1a, along with ER damage. These results suggest that Sidt2{sup −/−} mice had spontaneous

bis-Dehydroxy-Curcumin triggers mitochondrial-associated cell death in human colon cancer cells through ER-stress induced autophagy.

PubMed

Basile, Valentina; Belluti, Silvia; Ferrari, Erika; Gozzoli, Chiara; Ganassi, Sonia; Quaglino, Daniela; Saladini, Monica; Imbriano, Carol

2013-01-01

The activation of autophagy has been extensively described as a pro-survival strategy, which helps to keep cells alive following deprivation of nutrients/growth factors and other stressful cellular conditions. In addition to cytoprotective effects, autophagy can accompany cell death. Autophagic vacuoles can be observed before or during cell death, but the role of autophagy in the death process is still controversial. A complex interplay between autophagy and apoptosis has come to light, taking into account that numerous genes, such as p53 and Bcl-2 family members, are shared between these two pathways. In this study we showed a potent and irreversible cytotoxic activity of the stable Curcumin derivative bis-DeHydroxyCurcumin (bDHC) on human colon cancer cells, but not on human normal cells. Autophagy is elicited by bDHC before cell death as demonstrated by increased autophagosome formation -measured by electron microscopy, fluorescent LC3 puncta and LC3 lipidation- and autophagic flux -measured by interfering LC3-II turnover. The accumulation of poly-ubiquitinated proteins and ER-stress occurred upstream of autophagy induction and resulted in cell death. Cell cycle and Western blot analyses highlighted the activation of a mitochondrial-dependent apoptosis, which involves caspase 7, 8, 9 and Cytochrome C release. Using pharmacological inhibitions and RNAi experiments, we showed that ER-stress induced autophagy has a major role in triggering bDHC-cell death. Our findings describe the mechanism through which bDHC promotes tumor selective inhibition of proliferation, providing unequivocal evidence of the role of autophagy in contrasting the proliferation of colon cancer cells.

ALS Patient Stem Cells for Unveiling Disease Signatures of Motoneuron Susceptibility: Perspectives on the Deadly Mitochondria, ER Stress and Calcium Triad

PubMed Central

Kaus, Anjoscha; Sareen, Dhruv

2015-01-01

Amyotrophic lateral sclerosis (ALS) is a largely sporadic progressive neurodegenerative disease affecting upper and lower motoneurons (MNs) whose specific etiology is incompletely understood. Mutations in superoxide dismutase-1 (SOD1), TAR DNA-binding protein 43 (TARDBP/TDP-43) and C9orf72, have been identified in subsets of familial and sporadic patients. Key associated molecular and neuropathological features include ubiquitinated TDP-43 inclusions, stress granules, aggregated dipeptide proteins from mutant C9orf72 transcripts, altered mitochondrial ultrastructure, dysregulated calcium homeostasis, oxidative and endoplasmic reticulum (ER) stress, and an unfolded protein response (UPR). Such impairments have been documented in ALS animal models; however, whether these mechanisms are initiating factors or later consequential events leading to MN vulnerability in ALS patients is debatable. Human induced pluripotent stem cells (iPSCs) are a valuable tool that could resolve this “chicken or egg” causality dilemma. Relevant systems for probing pathophysiologically affected cells from large numbers of ALS patients and discovering phenotypic disease signatures of early MN susceptibility are described. Performing unbiased ‘OMICS and high-throughput screening in relevant neural cells from a cohort of ALS patient iPSCs, and rescuing mitochondrial and ER stress impairments, can identify targeted therapeutics for increasing MN longevity in ALS. PMID:26635528

Spermine Alleviates Drought Stress in White Clover with Different Resistance by Influencing Carbohydrate Metabolism and Dehydrins Synthesis

PubMed Central

Li, Zhou; Jing, Wen; Peng, Yan; Zhang, Xin Quan; Ma, Xiao; Huang, Lin Kai; Yan, Yan-hong

2015-01-01

The objective of this research was to analyse whether ameliorating drought stress through exogenously applied spermine (Spm) was related to carbohydrate metabolism, dehydrins accumulation and the transcription of genes encoding dehydrins in two white clovers (drought-susceptible cv. ‘Ladino’ and drought-resistant cv. ‘Haifa’) under controlled drying conditions for 10 days. The results show that the application of Spm effectively alleviates negative effects caused by drought stress in both cultivars. Exogenous Spm led to accumulation of more water-soluble carbohydrates (WSC), sucrose, fructose and sorbitol in both cultivars under drought stress, and also significantly elevated glucose content in leaves of drought-resistant cv. ‘Haifa’, but had no effect on drought-susceptible cv. ‘Ladino’. Accordingly, the key enzyme activities of sucrose and sorbitol metabolism changed along with the application of Spm under drought stress. Spm induced a significant increase in sucrose phosphate synthase (SPS) or sorbitol dehydrogenase (SDH) activity, but decrease in sucrose synthetase (SS) activity when two cultivars were subjected to drought. In addition, the improved accumulation of dehydrins induced by exogenous Spm coincided with three genes expression which was responsible for dehydrins synthesis. But Spm-induced transcript level of dehydrin genes increased earlier in cv. ‘Ladino’ than that in cv. ‘Haifa’. Thus, these results suggest that ameliorating drought stress through exogenously applied Spm may be associated with increased carbohydrate accumulation and dehydrins synthesis. There are differences between drought-susceptible and -resistant white clover cultivars related to Spm regulation of WSC metabolism and dehydrins expression. PMID:25835290

Low-level laser therapy with 850 nm recovers salivary function via membrane redistribution of aquaporin 5 by reducing intracellular Ca2+ overload and ER stress during hyperglycemia.

PubMed

Biswas, Raktim; Ahn, Jin Chul; Moon, Jeong Hwan; Kim, Jungbin; Choi, Young-Hoon; Park, So Young; Chung, Phil-Sang

2018-05-09

The overall goal is to study the effect of low-level laser therapy (LLLT) on membrane distribution of major water channel protein aquaporin 5 (AQP5) in salivary gland during hyperglycemia. Par C10 cells treated with high glucose (50 mM) showed a reduced membrane distribution of AQP5. The functional expression of AQP5 was downregulated due to intracellular Ca 2+ overload and ER stress. This reduction in AQP5 expression impairs water permeability and therefore results in hypo-salivation. A reduced salivary flow was also observed in streptozotocin (STZ)-induced diabetic mice model and the expression of AQP5 and phospho-AQP5 was downregulated. Low-level laser treatment with 850 nm (30 mW, 10 min = 18 J/cm 2 ) reduced ER stress and recovered AQP5 membrane distribution via serine phosphorylation in the cells. In the STZ-induced diabetic mouse, LLLT with 850 nm (60 J/cm 2 ) increased salivary flow and upregulated of AQP5 and p-AQP5. ER stress was also reduced via downregulation of caspase 12 and CHOP. In silico analysis confirmed that the serine 156 is one of the most favorable phosphorylation sites of AQP5 and may contribute to the stability of the protein. Therefore, this study suggests high glucose inhibits phosphorylation-dependent AQP5 membrane distribution. High glucose induces intracellular Ca 2+ overload and ER stress that disrupt AQP5 functional expression. Low-level laser therapy with 850 nm improves salivary function by increasing AQP5 membrane distribution in hyperglycemia-induced hyposalivation. Copyright © 2018. Published by Elsevier B.V.

Lipolysis Response to Endoplasmic Reticulum Stress in Adipose Cells*

PubMed Central

Deng, Jingna; Liu, Shangxin; Zou, Liangqiang; Xu, Chong; Geng, Bin; Xu, Guoheng

2012-01-01

In obesity and diabetes, adipocytes show significant endoplasmic reticulum (ER) stress, which triggers a series of responses. This study aimed to investigate the lipolysis response to ER stress in rat adipocytes. Thapsigargin, tunicamycin, and brefeldin A, which induce ER stress through different pathways, efficiently activated a time-dependent lipolytic reaction. The lipolytic effect of ER stress occurred with elevated cAMP production and protein kinase A (PKA) activity. Inhibition of PKA reduced PKA phosphosubstrates and attenuated the lipolysis. Although both ERK1/2 and JNK are activated during ER stress, lipolysis is partially suppressed by inhibiting ERK1/2 but not JNK and p38 MAPK and PKC. Thus, ER stress induces lipolysis by activating cAMP/PKA and ERK1/2. In the downstream lipolytic cascade, phosphorylation of lipid droplet-associated protein perilipin was significantly promoted during ER stress but attenuated on PKA inhibition. Furthermore, ER stress stimuli did not alter the levels of hormone-sensitive lipase and adipose triglyceride lipase but caused Ser-563 and Ser-660 phosphorylation of hormone-sensitive lipase and moderately elevated its translocation from the cytosol to lipid droplets. Accompanying these changes, total activity of cellular lipases was promoted to confer the lipolysis. These findings suggest a novel pathway of the lipolysis response to ER stress in adipocytes. This lipolytic activation may be an adaptive response that regulates energy homeostasis but with sustained ER stress challenge could contribute to lipotoxicity, dyslipidemia, and insulin resistance because of persistently accelerated free fatty acid efflux from adipocytes to the bloodstream and other tissues. PMID:22223650

Endoplasmic Reticulum Stress in Beta Cells and Development of Diabetes

PubMed Central

Fonseca, Sonya G.; Burcin, Mark; Gromada, Jesper; Urano, Fumihiko

2009-01-01

The endoplasmic reticulum (ER) is a cellular compartment responsible for multiple important cellular functions including the biosynthesis and folding of newly synthesized proteins destined for secretion, such as insulin. A myriad of pathological and physiological factors perturb ER function and cause dysregulation of ER homeostasis, leading to ER stress. ER stress elicits a signaling cascade to mitigate stress, the Unfolded Protein Response (UPR). As long as the UPR can relieve stress, cells can produce the proper amount of proteins and maintain ER homeostasis. If the UPR, however, fails to maintain ER homeostasis, cells will undergo apoptosis. Activation of the UPR is critical to the survival of insulin-producing pancreatic β-cells with high secretory protein production. Any disruption of ER homeostasis in β-cells can lead to cell death and contribute to the pathogenesis of diabetes. There are several models of ER stress-mediated diabetes. In this review, we outline the underlying molecular mechanisms of ER stress-mediated β-cell dysfunction and death during the progression of diabetes. PMID:19665428

Sigma-1 receptor chaperones at the ER-mitochondrion interface regulate Ca(2+) signaling and cell survival.

PubMed

Hayashi, Teruo; Su, Tsung-Ping

2007-11-02

Communication between the endoplasmic reticulum (ER) and mitochondrion is important for bioenergetics and cellular survival. The ER supplies Ca(2+) directly to mitochondria via inositol 1,4,5-trisphosphate receptors (IP3Rs) at close contacts between the two organelles referred to as mitochondrion-associated ER membrane (MAM). We found here that the ER protein sigma-1 receptor (Sig-1R), which is implicated in neuroprotection, carcinogenesis, and neuroplasticity, is a Ca(2+)-sensitive and ligand-operated receptor chaperone at MAM. Normally, Sig-1Rs form a complex at MAM with another chaperone, BiP. Upon ER Ca(2+) depletion or via ligand stimulation, Sig-1Rs dissociate from BiP, leading to a prolonged Ca(2+) signaling into mitochondria via IP3Rs. Sig-1Rs can translocate under chronic ER stress. Increasing Sig-1Rs in cells counteracts ER stress response, whereas decreasing them enhances apoptosis. These results reveal that the orchestrated ER chaperone machinery at MAM, by sensing ER Ca(2+) concentrations, regulates ER-mitochondrial interorganellar Ca(2+) signaling and cell survival.

The default response to uncertainty and the importance of perceived safety in anxiety and stress: An evolution-theoretical perspective.

PubMed

Brosschot, Jos F; Verkuil, Bart; Thayer, Julian F

2016-06-01

From a combined neurobiological and evolution-theoretical perspective, the stress response is a subcortically subserved response to uncertainty that is not 'generated' but 'default': the stress response is 'always there' but as long as safety is perceived, the stress response is under tonic prefrontal inhibition, reflected by high vagally mediated heart rate variability. Uncertainty of safety leads to disinhibiting the default stress response, even in the absence of threat. Due to the stress response's survival value, this 'erring on the side of caution' is passed to us via our genes. Thus, intolerance of uncertainty is not acquired during the life cycle, but is a given property of all living organisms, only to be alleviated in situations of which the safety is learned. When the latter is deficient, generalized unsafety ensues, which underlies chronic anxiety and stress and their somatic health risks, as well as other highly prevalent conditions carrying such risks, including loneliness, obesity, aerobic unfitness and old age. Copyright © 2016 Elsevier Ltd. All rights reserved.

Resveratrol alleviates diabetes-induced testicular dysfunction by inhibiting oxidative stress and c-Jun N-terminal kinase signaling in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faid, Iman; Al-Hussaini, Heba; Kilarkaje, Narayana, E-mail: knarayana@hsc.edu.kw

Diabetes adversely affects reproductive functions in humans and animals. The present study investigated the effects of Resveratrol on diabetes-induced alterations in oxidative stress, c-Jun N-terminal kinase (JNK) signaling and apoptosis in the testis. Adult male Wistar rats (13–15 weeks; n = 6/group) were segregated into 1) normal control, 2) Resveratrol-treated (5 mg/kg; ip; given during last 3 weeks), 3) Streptozotocin-induced diabetic and, 4) Resveratrol-treated diabetic groups, and euthanized on day 42 after the confirmation of diabetes. Resveratrol did not normalize blood glucose levels in diabetic rats. Resveratrol supplementation recovered diabetes-induced decreases in reproductive organ weights, sperm count and motility, intra-testicularmore » levels of superoxide dismutase, catalase, and glutathione peroxidase and an increase in 4-hydroxynonenal activities (P < 0.05). Resveratrol also recovered diabetes-induced increases in JNK signaling pathway proteins, namely, ASK1 (apoptosis signal-regulating kinase 1), JNKs (46 and 54 kDa isoforms) and p-JNK to normal control levels (P < 0.05). Interestingly, the expression of a down-stream target of ASK1, MKK4 (mitogen-activated protein kinase kinase 4) and its phosphorylated form (p-MKK4) did not change in experimental groups. Resveratrol inhibited diabetes-induced increases in AP-1 (activator protein-1) components, c-Jun and ATF2 (activating transcription factor 2), but not their phosphorylated forms, to normal control levels (P < 0.05). Further, Resveratrol inhibited diabetes-induced increase in cleaved-caspase-3 to normal control levels. In conclusion, Resveratrol alleviates diabetes-induced apoptosis in testis by modulating oxidative stress, JNK signaling pathway and caspase-3 activities, but not by inhibiting hyperglycemia, in rats. These results suggest that Resveratrol supplementation may be a useful strategy to treat diabetes-induced testicular dysfunction. - Highlights: • Resveratrol up

Endoplasmic Reticulum Stress Links Oxidative Stress to Impaired Pancreatic Beta-Cell Function Caused by Human Oxidized LDL.

PubMed

Plaisance, Valérie; Brajkovic, Saška; Tenenbaum, Mathie; Favre, Dimitri; Ezanno, Hélène; Bonnefond, Amélie; Bonner, Caroline; Gmyr, Valéry; Kerr-Conte, Julie; Gauthier, Benoit R; Widmann, Christian; Waeber, Gérard; Pattou, François; Froguel, Philippe; Abderrahmani, Amar

2016-01-01

Elevated plasma concentration of the pro-atherogenic oxidized low density lipoprotein cholesterol (LDL) triggers adverse effects in pancreatic beta-cells and is associated with type 2 diabetes. Here, we investigated whether the endoplasmic reticulum (ER) stress is a key player coupling oxidative stress to beta-cell dysfunction and death elicited by human oxidized LDL. We found that human oxidized LDL activates ER stress as evidenced by the activation of the inositol requiring 1α, and the elevated expression of both DDIT3 (also called CHOP) and DNAJC3 (also called P58IPK) ER stress markers in isolated human islets and the mouse insulin secreting MIN6 cells. Silencing of Chop and inhibition of ER stress markers by the chemical chaperone phenyl butyric acid (PBA) prevented cell death caused by oxidized LDL. Finally, we found that oxidative stress accounts for activation of ER stress markers induced by oxidized LDL. Induction of Chop/CHOP and p58IPK/P58IPK by oxidized LDL was mimicked by hydrogen peroxide and was blocked by co-treatment with the N-acetylcystein antioxidant. As a conclusion, the harmful effects of oxidized LDL in beta-cells requires ER stress activation in a manner that involves oxidative stress. This mechanism may account for impaired beta-cell function in diabetes and can be reversed by antioxidant treatment.

Endoplasmic Reticulum Stress and Lipid Metabolism: Mechanisms and Therapeutic Potential

PubMed Central

Basseri, Sana; Austin, Richard C.

2012-01-01

The endoplasmic reticulum (ER) plays a crucial role in protein folding, assembly, and secretion. Disruption of ER homeostasis may lead to accumulation of misfolded or unfolded proteins in the ER lumen, a condition referred to as ER stress. In response to ER stress, a signal transduction pathway known as the unfolded protein response (UPR) is activated. UPR activation allows the cell to cope with an increased protein-folding demand on the ER. Recent studies have shown that ER stress/UPR activation plays a critical role in lipid metabolism and homeostasis. ER-stress-dependent dysregulation of lipid metabolism may lead to dyslipidemia, insulin resistance, cardiovascular disease, type 2 diabetes, and obesity. In this paper, we examine recent findings illustrating the important role ER stress/UPR signalling pathways play in regulation of lipid metabolism, and how they may lead to dysregulation of lipid homeostasis. PMID:22195283