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Sample records for reticulum stress sensor

  1. BODIPY-Coumarin Conjugate as an Endoplasmic Reticulum Membrane Fluidity Sensor and Its Application to ER Stress Models.

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    Lee, Hoyeon; Yang, Zhigang; Wi, Youngjin; Kim, Tae Woo; Verwilst, Peter; Lee, Yun Hak; Han, Ga-In; Kang, Chulhun; Kim, Jong Seung

    2015-12-16

    An endoplasmic reticulum (ER) membrane-selective chemosensor composed of BODIPY and coumarin moieties and a long alkyl chain (n-C18) was synthesized. The emission ratio of BODIPY to coumarin depends on the solution viscosity. The probe is localized to the ER membrane and was applied to reveal the reduced ER membrane fluidity under ER stress conditions.

  2. The Endoplasmic Reticulum Stress Sensor Inositol-Requiring Enzyme 1α Augments Bacterial Killing through Sustained Oxidant Production.

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    Abuaita, Basel H; Burkholder, Kristin M; Boles, Blaise R; O'Riordan, Mary X

    2015-07-14

    Bacterial infection can trigger cellular stress programs, such as the unfolded protein response (UPR), which occurs when misfolded proteins accumulate within the endoplasmic reticulum (ER). Here, we used the human pathogen methicillin-resistant Staphylococcus aureus (MRSA) as an infection model to probe how ER stress promotes antimicrobial function. MRSA infection activated the most highly conserved unfolded protein response sensor, inositol-requiring enzyme 1α (IRE1α), which was necessary for robust bacterial killing in vitro and in vivo. The macrophage IRE1-dependent bactericidal activity required reactive oxygen species (ROS). Viable MRSA cells excluded ROS from the nascent phagosome and strongly triggered IRE1 activation, leading to sustained generation of ROS that were largely Nox2 independent. In contrast, dead MRSA showed early colocalization with ROS but was a poor activator of IRE1 and did not trigger sustained ROS generation. The global ROS stimulated by IRE1 signaling was necessary, but not sufficient, for MRSA killing, which also required the ER resident SNARE Sec22B for accumulation of ROS in the phagosomal compartment. Taken together, these results suggest that IRE1-mediated persistent ROS generation might act as a fail-safe mechanism to kill bacterial pathogens that evade the initial macrophage oxidative burst. Cellular stress programs have been implicated as important components of the innate immune response to infection. The role of the IRE1 pathway of the ER stress response in immune secretory functions, such as antibody production, is well established, but its contribution to innate immunity is less well defined. Here, we show that infection of macrophages with viable MRSA induces IRE1 activation, leading to bacterial killing. IRE1-dependent bactericidal activity required generation of reactive oxygen species in a sustained manner over hours of infection. The SNARE protein Sec22B, which was previously demonstrated to control ER

  3. Endoplasmic reticulum stress in lung disease

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    Stefan J. Marciniak

    2017-06-01

    Full Text Available Exposure to inhaled pollutants, including fine particulates and cigarette smoke is a major cause of lung disease in Europe. While it is established that inhaled pollutants have devastating effects on the genome, it is now recognised that additional effects on protein folding also drive the development of lung disease. Protein misfolding in the endoplasmic reticulum affects the pathogenesis of many diseases, ranging from pulmonary fibrosis to cancer. It is therefore important to understand how cells respond to endoplasmic reticulum stress and how this affects pulmonary tissues in disease. These insights may offer opportunities to manipulate such endoplasmic reticulum stress pathways and thereby cure lung disease.

  4. Endoplasmic Reticulum Stress and Associated ROS

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    Hafiz Maher Ali Zeeshan

    2016-03-01

    Full Text Available The endoplasmic reticulum (ER is a fascinating network of tubules through which secretory and transmembrane proteins enter unfolded and exit as either folded or misfolded proteins, after which they are directed either toward other organelles or to degradation, respectively. The ER redox environment dictates the fate of entering proteins, and the level of redox signaling mediators modulates the level of reactive oxygen species (ROS. Accumulating evidence suggests the interrelation of ER stress and ROS with redox signaling mediators such as protein disulfide isomerase (PDI-endoplasmic reticulum oxidoreductin (ERO-1, glutathione (GSH/glutathione disuphide (GSSG, NADPH oxidase 4 (Nox4, NADPH-P450 reductase (NPR, and calcium. Here, we reviewed persistent ER stress and protein misfolding-initiated ROS cascades and their significant roles in the pathogenesis of multiple human disorders, including neurodegenerative diseases, diabetes mellitus, atherosclerosis, inflammation, ischemia, and kidney and liver diseases.

  5. Endoplasmic Reticulum (ER) Stress and Endocrine Disorders

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    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

  6. Endoplasmic Reticulum (ER) Stress and Endocrine Disorders.

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    Ariyasu, Daisuke; Yoshida, Hiderou; Hasegawa, Yukihiro

    2017-02-11

    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.

  7. Endoplasmic Reticulum (ER Stress and Endocrine Disorders

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    Daisuke Ariyasu

    2017-02-01

    Full Text Available 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.

  8. Endoplasmic reticulum: ER stress regulates mitochondrial bioenergetics

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    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

  9. Endoplasmic reticulum stress and diabetic retinopathy

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    Toshiyuki Oshitari

    2008-02-01

    Full Text Available Toshiyuki Oshitari1,2, Natsuyo Hata1, Shuichi Yamamoto11Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Chiba City, Chiba, Japan; 2Department of Ophthalmology, Kimitsu Central Hospital, Kisarazu City, Chiba, JapanAbstract: Endoplasmic reticulum (ER stress is involved in the pathogenesis of several diseases including Alzheimer disease and Parkinson disease. Many recent studies have shown that ER stress is related to the pathogenesis of diabetes mellitus, and with the death of pancreatic β-cells, insulin resistance, and the death of the vascular cells in the retina. Diabetic retinopathy is a major complication of diabetes and results in death of both neural and vascular cells. Because the death of the neurons directly affects visual function, the precise mechanism causing the death of neurons in early diabetic retinopathy must be determined. The ideal therapy for preventing the onset and the progression of diabetic retinopathy would be to treat the factors involved with both the vascular and neuronal abnormalities in diabetic retinopathy. In this review, we present evidence that ER stress is involved in the death of both retinal neurons and vascular cells in diabetic eyes, and thus reducing or blocking ER stress may be a potential therapy for preventing the onset and the progression of diabetic retinopathy.Keywords: endoplasmic reticulum stress, diabetic retinopathy, vascular cell death, neuronal cell death

  10. Endoplasmic Reticulum Stress and Ethanol Neurotoxicity

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    Fanmuyi Yang

    2015-10-01

    Full Text Available Ethanol abuse affects virtually all organ systems and the central nervous system (CNS is particularly vulnerable to excessive ethanol exposure. Ethanol exposure causes profound damages to both the adult and developing brain. Prenatal ethanol exposure induces fetal alcohol spectrum disorders (FASD which is associated with mental retardation and other behavioral deficits. A number of potential mechanisms have been proposed for ethanol-induced brain damage; these include the promotion of neuroinflammation, interference with signaling by neurotrophic factors, induction of oxidative stress, modulation of retinoid acid signaling, and thiamine deficiency. The endoplasmic reticulum (ER regulates posttranslational protein processing and transport. The accumulation of unfolded or misfolded proteins in the ER lumen triggers ER stress and induces unfolded protein response (UPR which are mediated by three transmembrane ER signaling proteins: pancreatic endoplasmic reticulum kinase (PERK, inositol-requiring enzyme 1 (IRE1, and activating transcription factor 6 (ATF6. UPR is initiated to protect cells from overwhelming ER protein loading. However, sustained ER stress may result in cell death. ER stress has been implied in various CNS injuries, including brain ischemia, traumatic brain injury, and aging-associated neurodegeneration, such as Alzheimer’s disease (AD, Huntington’s disease (HD, Amyotrophic lateral sclerosis (ALS, and Parkinson’s disease (PD. However, effects of ethanol on ER stress in the CNS receive less attention. In this review, we discuss recent progress in the study of ER stress in ethanol-induced neurotoxicity. We also examine the potential mechanisms underlying ethanol-mediated ER stress and the interaction among ER stress, oxidative stress and autophagy in the context of ethanol neurotoxicity.

  11. Endoplasmic reticulum stress and cardiovascular diseases

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    Xiaohui Duan; Yongfen Qi; Chaoshu Tang

    2009-01-01

    The endoplasmic reticulum (ER) serves several important functions, mainly post-translational modification, folding and assembly of newly synthesized secretary proteins, synthesizing lipids and cellular calcium storage. Various factors can disrupt ER homeostasis and disturb its functions, which leads to the accumulation of unfolded and misfolded proteins and to potential cellular dysfunction and pathological consequences, collectively termed ER stress. Recent progress suggests that ER stress plays a key role in the immune response, diabetes, tumor growth, and some neurodegenerative diseases. In particular, ER stress is involved in several processes of cardiovascular diseases, such as ischemia/reperfusion injury, cardiomyopathy, cardiac hypertrophy, heart failure, and atherosclerosis. Further research on the relation of ER stress to cardiovascular diseases will greatly enhance the understanding of these pathological processes and provide novel avenues to potential therapies.

  12. Endoplasmic Reticulum Stress and Diabetic Cardiomyopathy

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    Jiancheng Xu

    2012-01-01

    Full Text Available The endoplasmic reticulum (ER is an organelle entrusted with lipid synthesis, calcium homeostasis, protein folding, and maturation. Perturbation of ER-associated functions results in an evolutionarily conserved cell stress response, the unfolded protein response (UPR that is also called ER stress. ER stress is aimed initially at compensating for damage but can eventually trigger cell death if ER stress is excessive or prolonged. Now the ER stress has been associated with numerous diseases. For instance, our recent studies have demonstrated the important role of ER stress in diabetes-induced cardiac cell death. It is known that apoptosis has been considered to play a critical role in diabetic cardiomyopathy. Therefore, this paper will summarize the information from the literature and our own studies to focus on the pathological role of ER stress in the development of diabetic cardiomyopathy. Improved understanding of the molecular mechanisms underlying UPR activation and ER-initiated apoptosis in diabetic cardiomyopathy will provide us with new targets for drug discovery and therapeutic intervention.

  13. Targeting endoplasmic reticulum stress in insulin resistance.

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    Salvadó, Laia; Palomer, Xavier; Barroso, Emma; Vázquez-Carrera, Manuel

    2015-08-01

    The endoplasmic reticulum (ER) is involved in the development of insulin resistance and progression to type 2 diabetes mellitus (T2DM). Disruption of ER homeostasis leads to ER stress, which activates the unfolded protein response (UPR). This response is linked to different processes involved in the development of insulin resistance (IR) and T2DM, including inflammation, lipid accumulation, insulin biosynthesis, and β-cell apoptosis. Understanding the mechanisms by which disruption of ER homeostasis leads to IR and its progression to T2DM may offer new pharmacological targets for the treatment and prevention of these diseases. Here, we examine ER stress, the UPR, and downstream pathways in insulin sensitive tissues, and in IR, and offer insights towards therapeutic strategies.

  14. Endoplasmic reticulum stress in periimplantation embryos.

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    Michalak, Marek; Gye, Myung Chan

    2015-03-01

    Stress coping mechanisms are critical to minimize or overcome damage caused by ever changing environmental conditions. They are designed to promote cell survival. The unfolded protein response (UPR) pathway is mobilized in response to the accumulation of unfolded proteins, ultimately in order to regain endoplasmic reticulum (ER) homeostasis. Various elements of coping responses to ER stress including Perk, Ask1, Bip, Chop, Gadd34, Ire1, Atf4, Atf6, and Xbp1 have been identified and were found to be inducible in oocytes and preimplantation embryos, suggesting that, as a normal part of the cellular adaptive mechanism, these coping responses, including the UPR, play a pivotal role in the development of preimplantation embryos. As such, the UPR-associated molecules and pathways may become useful markers for the potential diagnosis of stress conditions for preimplantation embryos. After implantation, ER stress-induced coping responses become physiologically important for a normal decidual response, placentation, and early organogenesis. Attenuation of ER stress coping responses by tauroursodeoxycholate and salubrinal was effective for prevention of cell death of cultured embryos. Further elucidation of new and relevant ER stress coping responses in periimplantation embryos might contribute to a comprehensive understanding of the regulation of normal development of embryonic development and potentiation of embryonic development in vitro.

  15. Development of Endoplasmic Reticulum Stress during Experimental Oxalate Nephrolithiasis.

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    Motin, Yu G; Lepilov, A V; Bgatova, N P; Zharikov, A Yu; Motina, N V; Lapii, G A; Lushnikova, E L; Nepomnyashchikh, L M

    2016-01-01

    Morphological and ultrastructural study of the kidney was performed in rats with oxalate nephrolithiasis. Specific features of endoplasmic reticulum stress were evaluated during nephrolithiasis and treatment with α-tocopherol. We observed the signs of endoplasmic reticulum stress with activation of proapoptotic pathways and injury to the cell lining in nephron tubules and collecting ducts. Ultrastructural changes were found in the organelles, nuclei, and cell membranes of epitheliocytes. A relationship was revealed between endoplasmic reticulum stress and oxidative damage, which developed at the early state of lithogenesis.

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

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    Namrata eChaudhari

    2014-07-01

    Full Text Available 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 disturb 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 has 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.

  17. Endoplasmic Reticulum Stress and Insulin Biosynthesis: A Review

    OpenAIRE

    2012-01-01

    Insulin resistance and pancreatic beta cell dysfunction are major contributors to the pathogenesis of diabetes. Various conditions play a role in the pathogenesis of pancreatic beta cell dysfunction and are correlated with endoplasmic reticulum (ER) stress. Pancreatic beta cells are susceptible to ER stress. Many studies have shown that increased ER stress induces pancreatic beta cell dysfunction and diabetes mellitus using genetic models of ER stress and by various stimuli. There are many re...

  18. Endoplasmic Reticulum Stress Mediates Methamphetamine-Induced Blood-Brain Barrier Damage.

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    Qie, Xiaojuan; Wen, Di; Guo, Hongyan; Xu, Guanjie; Liu, Shuai; Shen, Qianchao; Liu, Yi; Zhang, Wenfang; Cong, Bin; Ma, Chunling

    2017-01-01

    Methamphetamine (METH) abuse causes serious health problems worldwide, and long-term use of METH disrupts the blood-brain barrier (BBB). Herein, we explored the potential mechanism of endoplasmic reticulum (ER) stress in METH-induced BBB endothelial cell damage in vitro and the therapeutic potential of endoplasmic reticulum stress inhibitors for METH-induced BBB disruption in C57BL/6J mice. Exposure of immortalized BMVEC (bEnd.3) cells to METH significantly decreased cell viability, induced apoptosis, and diminished the tightness of cell monolayers. METH activated ER stress sensor proteins, including PERK, ATF6, and IRE1, and upregulated the pro-apoptotic protein CHOP. The ER stress inhibitors significantly blocked the upregulation of CHOP. Knockdown of CHOP protected bEnd.3 cells from METH-induced cytotoxicity. Furthermore, METH elevated the production of reactive oxygen species (ROS) and induced the dysfunction of mitochondrial characterized by a Bcl2/Bax ratio decrease, mitochondrial membrane potential collapse, and cytochrome c. ER stress release was partially reversed by ROS inhibition, and cytochrome c release was partially blocked by knockdown of CHOP. Finally, PBA significantly attenuated METH-induced sodium fluorescein (NaFluo) and Evans Blue leakage, as well as tight junction protein loss, in C57BL/6J mice. These data suggest that BBB endothelial cell damage was caused by METH-induced endoplasmic reticulum stress, which further induced mitochondrial dysfunction, and that PBA was an effective treatment for METH-induced BBB disruption.

  19. Misfolded proteins, endoplasmic reticulum stress and neurodegeneration

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    Rao, Rammohan V.; Bredesen, Dale E.

    2004-01-01

    The accumulation of misfolded proteins (e.g. mutant or damaged proteins) triggers cellular stress responses that protect cells against the toxic buildup of such proteins. However, prolonged stress due to the buildup of these toxic proteins induces specific death pathways. Dissecting these pathways should be valuable in understanding the pathogenesis of, and ultimately in designing therapy for, neurodegenerative diseases that feature misfolded proteins.

  20. Endoplasmic Reticulum Stress and Insulin Biosynthesis: A Review

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    Mi-Kyung Kim

    2012-01-01

    Full Text Available Insulin resistance and pancreatic beta cell dysfunction are major contributors to the pathogenesis of diabetes. Various conditions play a role in the pathogenesis of pancreatic beta cell dysfunction and are correlated with endoplasmic reticulum (ER stress. Pancreatic beta cells are susceptible to ER stress. Many studies have shown that increased ER stress induces pancreatic beta cell dysfunction and diabetes mellitus using genetic models of ER stress and by various stimuli. There are many reports indicating that ER stress plays an important role in the impairment of insulin biosynthesis, suggesting that reduction of ER stress could be a therapeutic target for diabetes. In this paper, we reviewed the relationship between ER stress and diabetes and how ER stress controls insulin biosynthesis.

  1. Endoplasmic reticulum stress and insulin biosynthesis: a review.

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    Kim, Mi-Kyung; Kim, Hye-Soon; Lee, In-Kyu; Park, Keun-Gyu

    2012-01-01

    Insulin resistance and pancreatic beta cell dysfunction are major contributors to the pathogenesis of diabetes. Various conditions play a role in the pathogenesis of pancreatic beta cell dysfunction and are correlated with endoplasmic reticulum (ER) stress. Pancreatic beta cells are susceptible to ER stress. Many studies have shown that increased ER stress induces pancreatic beta cell dysfunction and diabetes mellitus using genetic models of ER stress and by various stimuli. There are many reports indicating that ER stress plays an important role in the impairment of insulin biosynthesis, suggesting that reduction of ER stress could be a therapeutic target for diabetes. In this paper, we reviewed the relationship between ER stress and diabetes and how ER stress controls insulin biosynthesis.

  2. Fluoride induced endoplasmic reticulum stress and calcium overload in ameloblasts.

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    Zhang, Ying; Zhang, KaiQiang; Ma, Lin; Gu, HeFeng; Li, Jian; Lei, Shuang

    2016-09-01

    The aim of the study was to evaluate the involvement of endoplasmic reticulum stress and intracellular calcium overload on the development of dental fluorosis. We cultured and exposed rat ameloblast HAT-7 cells to various concentrations of fluoride and measured apoptosis with flow cytometry and intracellular Ca2+ changes using confocal microscopy, investigated the protein levels of GRP78, calreticulin, XBP1 and CHOP by western blotting, and their transcriptional levels with RT-PCR. We also created an in vivo model of dental fluorosis by exposing animals to various concentrations of fluoride. Subsequently, thin dental tissue slices were analyzed with H&E staining, immunohistochemical staining, and transmission electron microscopy, TUNEL assay was also performed on dental tissue slices for assessment of apoptosis. High fluoride concentration was associated with decreased ameloblast proliferation, elevated ameloblast apoptosis, and increased intracellular Ca2+ in vitro. The translation and transcription of the proteins associated with endoplasmic reticulum stress were significantly elevated with high concentrations of fluoride. Based on immunohistochemical staining, these proteins were also highly expressed in animals exposed to high fluoride concentrations. Histologically, we found significant fluorosis-like changes in tissues from animals exposed to high fluoride concentrations. Transmission electron microscopy cytology indicated significant apoptotic changes in tissues exposed to high concentrations of fluoride. These results indicate that exposure to high levels of fluoride led to endoplasmic reticulum stress which induced apoptosis in cultured ameloblasts and in vivo rat model, suggesting an important role of calcium overload and endoplasmic reticulum stress triggered by high concentrations of fluoride in the development of dental fluorosis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Contact stress sensor

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    Kotovsky, Jack [Oakland, CA

    2012-02-07

    A contact stress sensor includes one or more MEMS fabricated sensor elements, where each sensor element of includes a thin non-recessed portion, a recessed portion and a pressure sensitive element adjacent to the recessed portion. An electric circuit is connected to the pressure sensitive element. The circuit includes a thermal compensator and a pressure signal circuit element configured to provide a signal upon movement of the pressure sensitive element.

  4. Contact stress sensor

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    Kotovsky, Jack

    2014-02-11

    A method for producing a contact stress sensor that includes one or more MEMS fabricated sensor elements, where each sensor element of includes a thin non-recessed portion, a recessed portion and a pressure sensitive element adjacent to the recessed portion. An electric circuit is connected to the pressure sensitive element. The circuit includes a pressure signal circuit element configured to provide a signal upon movement of the pressure sensitive element.

  5. Endoplasmic reticulum stress, diabetes mellitus, and tissue injury.

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    Huang, Liu; Xie, Hong; Liu, Hao

    2014-01-01

    Endoplasmic reticulum (ER) stress is characterized by the accumulation of unfolded and misfolded proteins in the ER lumen. Unfolded and misfolded protein accumulation interferes with the ER function and triggers ER stress response. Thus, ER stress response, also called unfolded protein response (UPR), is an adaptive process that controls the protein amount in the ER lumen and the downstream protein demand. In normal conditions, the role of ER stress is to maintain ER homeostasis, restore ER function, and protect stressed cells from apoptosis, by coordinating gene expression, protein synthesis, and accelerating protein degradation through several molecular pathways. However, prolonged ER stress response plays a paradoxical role, which leads to cell damage, apoptosis, and concomitant tissue injuries. A number of tissue alterations are involved with diabetes mellitus progress and its comorbidities via ER stress. However, certain pharmacological agents affecting ER stress have been identified. In this review, we summarized the relationship between ER stress and insulin resistance development. Moreover, we aim to explain how ER stress influences type 2 diabetes mellitus (T2DM) development. In addition, we reviewed the literature on ER stress and UPR in three kinds of tissue injuries induced by T2DM. Finally, a retrospective analysis of the effects of anti-diabetes medications on ER stress is presented.

  6. Endoplasmic reticulum stress in spinal and bulbar muscular atrophy: a potential target for therapy.

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    Montague, Karli; Malik, Bilal; Gray, Anna L; La Spada, Albert R; Hanna, Michael G; Szabadkai, Gyorgy; Greensmith, Linda

    2014-07-01

    Spinal and bulbar muscular atrophy is an X-linked degenerative motor neuron disease caused by an abnormal expansion in the polyglutamine encoding CAG repeat of the androgen receptor gene. There is evidence implicating endoplasmic reticulum stress in the development and progression of neurodegenerative disease, including polyglutamine disorders such as Huntington's disease and in motor neuron disease, where cellular stress disrupts functioning of the endoplasmic reticulum, leading to induction of the unfolded protein response. We examined whether endoplasmic reticulum stress is also involved in the pathogenesis of spinal and bulbar muscular atrophy. Spinal and bulbar muscular atrophy mice that carry 100 pathogenic polyglutamine repeats in the androgen receptor, and develop a late-onset neuromuscular phenotype with motor neuron degeneration, were studied. We observed a disturbance in endoplasmic reticulum-associated calcium homeostasis in cultured embryonic motor neurons from spinal and bulbar muscular atrophy mice, which was accompanied by increased endoplasmic reticulum stress. Furthermore, pharmacological inhibition of endoplasmic reticulum stress reduced the endoplasmic reticulum-associated cell death pathway. Examination of spinal cord motor neurons of pathogenic mice at different disease stages revealed elevated expression of markers for endoplasmic reticulum stress, confirming an increase in this stress response in vivo. Importantly, the most significant increase was detected presymptomatically, suggesting that endoplasmic reticulum stress may play an early and possibly causal role in disease pathogenesis. Our results therefore indicate that the endoplasmic reticulum stress pathway could potentially be a therapeutic target for spinal and bulbar muscular atrophy and related polyglutamine diseases.

  7. Infusion of glucose and lipids at physiological rates causes acute endoplasmic reticulum stress in rat liver.

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    Boden, Guenther; Song, Weiwei; Duan, Xunbao; Cheung, Peter; Kresge, Karen; Barrero, Carlos; Merali, Salim

    2011-07-01

    Endoplasmic reticulum (ER) stress has recently been implicated as a cause for obesity-related insulin resistance; however, what causes ER stress in obesity has remained uncertain. Here, we have tested the hypothesis that macronutrients can cause acute (ER) stress in rat liver. Examined were the effects of intravenously infused glucose and/or lipids on proximal ER stress sensor activation (PERK, eIF2-α, ATF4, Xbox protein 1 (XBP1s)), unfolded protein response (UPR) proteins (GRP78, calnexin, calreticulin, protein disulphide isomerase (PDI), stress kinases (JNK, p38 MAPK) and insulin signaling (insulin/receptor substrate (IRS) 1/2 associated phosphoinositol-3-kinase (PI3K)) in rat liver. Glucose and/or lipid infusions, ranging from 23.8 to 69.5 kJ/4 h (equivalent to between ~17% and ~50% of normal daily energy intake), activated the proximal ER stress sensor PERK and ATF6 increased the protein abundance of calnexin, calreticulin and PDI and increased two GRP78 isoforms. Glucose and glucose plus lipid infusions induced comparable degrees of ER stress, but only infusions containing lipid activated stress kinases (JNK and p38 MAPK) and inhibited insulin signaling (PI3K). In summary, physiologic amounts of both glucose and lipids acutely increased ER stress in livers 12-h fasted rats and dependent on the presence of fat, caused insulin resistance. We conclude that this type of acute ER stress is likely to occur during normal daily nutrient intake.

  8. Induction of Apoptosis by Hypertension Via Endoplasmic Reticulum Stress

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    Yingying Sun

    2015-02-01

    Full Text Available Background/Aims: Endoplasmic reticulum (ER stress is one of the intrinsic apoptosis pathways, and cardiac apoptosis can occur in cardiovascular diseases, such as hypertension. However, the mechanisms by which ER stress leads to apoptosis remain enigmatic, particularly in the progression from cardiac hypertrophy to diastolic heart failure due to hypertension. Methods: We used spontaneously hypertensive rats (SHRs to investigate possible signalling pathways for ER stress. Results: We found that cardiac protein and mRNA levels of glucose-regulated protein 78 were up-regulated. In addition, the CHOP- and caspase-12-dependent pathways, but not that of JNK, were activated in the SHR rats. Conclusions: These results suggest that ER stress can contribute to myocardial apoptosis during hypertensive disease.

  9. Acetic Acid Causes Endoplasmic Reticulum Stress and Induces the Unfolded Protein Response in Saccharomyces cerevisiae

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    Nozomi Kawazoe

    2017-06-01

    Full Text Available Since acetic acid inhibits the growth and fermentation ability of Saccharomyces cerevisiae, it is one of the practical hindrances to the efficient production of bioethanol from a lignocellulosic biomass. Although extensive information is available on yeast response to acetic acid stress, the involvement of endoplasmic reticulum (ER and unfolded protein response (UPR has not been addressed. We herein demonstrated that acetic acid causes ER stress and induces the UPR. The accumulation of misfolded proteins in the ER and activation of Ire1p and Hac1p, an ER-stress sensor and ER stress-responsive transcription factor, respectively, were induced by a treatment with acetic acid stress (>0.2% v/v. Other monocarboxylic acids such as propionic acid and sorbic acid, but not lactic acid, also induced the UPR. Additionally, ire1Δ and hac1Δ cells were more sensitive to acetic acid than wild-type cells, indicating that activation of the Ire1p-Hac1p pathway is required for maximum tolerance to acetic acid. Furthermore, the combination of mild acetic acid stress (0.1% acetic acid and mild ethanol stress (5% ethanol induced the UPR, whereas neither mild ethanol stress nor mild acetic acid stress individually activated Ire1p, suggesting that ER stress is easily induced in yeast cells during the fermentation process of lignocellulosic hydrolysates. It was possible to avoid the induction of ER stress caused by acetic acid and the combined stress by adjusting extracellular pH.

  10. Acetic Acid Causes Endoplasmic Reticulum Stress and Induces the Unfolded Protein Response in Saccharomyces cerevisiae.

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    Kawazoe, Nozomi; Kimata, Yukio; Izawa, Shingo

    2017-01-01

    Since acetic acid inhibits the growth and fermentation ability of Saccharomyces cerevisiae, it is one of the practical hindrances to the efficient production of bioethanol from a lignocellulosic biomass. Although extensive information is available on yeast response to acetic acid stress, the involvement of endoplasmic reticulum (ER) and unfolded protein response (UPR) has not been addressed. We herein demonstrated that acetic acid causes ER stress and induces the UPR. The accumulation of misfolded proteins in the ER and activation of Ire1p and Hac1p, an ER-stress sensor and ER stress-responsive transcription factor, respectively, were induced by a treatment with acetic acid stress (>0.2% v/v). Other monocarboxylic acids such as propionic acid and sorbic acid, but not lactic acid, also induced the UPR. Additionally, ire1Δ and hac1Δ cells were more sensitive to acetic acid than wild-type cells, indicating that activation of the Ire1p-Hac1p pathway is required for maximum tolerance to acetic acid. Furthermore, the combination of mild acetic acid stress (0.1% acetic acid) and mild ethanol stress (5% ethanol) induced the UPR, whereas neither mild ethanol stress nor mild acetic acid stress individually activated Ire1p, suggesting that ER stress is easily induced in yeast cells during the fermentation process of lignocellulosic hydrolysates. It was possible to avoid the induction of ER stress caused by acetic acid and the combined stress by adjusting extracellular pH.

  11. Endoplasmic reticulum stress in adipose tissue augments lipolysis.

    Science.gov (United States)

    Bogdanovic, Elena; Kraus, Nicole; Patsouris, David; Diao, Li; Wang, Vivian; Abdullahi, Abdikarim; Jeschke, Marc G

    2015-01-01

    The endoplasmic reticulum (ER) is an organelle important for protein synthesis and folding, lipid synthesis and Ca(2+) homoeostasis. Consequently, ER stress or dysfunction affects numerous cellular processes and has been implicated as a contributing factor in several pathophysiological conditions. Tunicamycin induces ER stress in various cell types in vitro as well as in vivo. In mice, a hallmark of tunicamycin administration is the development of fatty livers within 24-48 hrs accompanied by hepatic ER stress. We hypothesized that tunicamycin would induce ER stress in adipose tissue that would lead to increased lipolysis and subsequently to fatty infiltration of the liver and hepatomegaly. Our results show that intraperitoneal administration of tunicamycin rapidly induced an ER stress response in adipose tissue that correlated with increased circulating free fatty acids (FFAs) and glycerol along with decreased adipose tissue mass and lipid droplet size. Furthermore, we found that in addition to fatty infiltration of the liver as well as hepatomegaly, lipid accumulation was also present in the heart, skeletal muscle and kidney. To corroborate our findings to a clinical setting, we examined adipose tissue from burned patients where increases in lipolysis and the development of fatty livers have been well documented. We found that burned patients displayed significant ER stress within adipose tissue and that ER stress augments lipolysis in cultured human adipocytes. Our results indicate a possible role for ER stress induced lipolysis in adipose tissue as an underlying mechanism contributing to increases in circulating FFAs and fatty infiltration into other organs.

  12. Sertraline induces endoplasmic reticulum stress in hepatic cells.

    Science.gov (United States)

    Chen, Si; Xuan, Jiekun; Couch, Letha; Iyer, Advait; Wu, Yuanfeng; Li, Quan-Zhen; Guo, Lei

    2014-08-01

    Sertraline is used for the treatment of depression, and is also used for the treatment of panic, obsessive-compulsive, and post-traumatic stress disorders. Previously, we have demonstrated that sertraline caused hepatic cytotoxicity, with mitochondrial dysfunction and apoptosis being underlying mechanisms. In this study, we used microarray and other biochemical and molecular analyses to identify endoplasmic reticulum (ER) stress as a novel molecular mechanism. HepG2 cells were exposed to sertraline and subjected to whole genome gene expression microarray analysis. Pathway analysis revealed that ER stress is among the significantly affected biological changes. We confirmed the increased expression of ER stress makers by real-time PCR and Western blots. The expression of typical ER stress markers such as PERK, IRE1α, and CHOP was significantly increased. To study better ER stress-mediated drug-induced liver toxicity; we established in vitro systems for monitoring ER stress quantitatively and efficiently, using Gaussia luciferase (Gluc) and secreted alkaline phosphatase (SEAP) as ER stress reporters. These in vitro systems were validated using well-known ER stress inducers. In these two reporter assays, sertraline inhibited the secretion of Gluc and SEAP. Moreover, we demonstrated that sertraline-induced apoptosis was coupled to ER stress and that the apoptotic effect was attenuated by 4-phenylbutyrate, a potent ER stress inhibitor. In addition, we showed that the MAP4K4-JNK signaling pathway contributed to the process of sertraline-induced ER stress. In summary, we demonstrated that ER stress is a mechanism of sertraline-induced liver toxicity.

  13. Lipolysis Response to Endoplasmic Reticulum Stress in Adipose Cells*

    Science.gov (United States)

    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

  14. Lipolysis response to endoplasmic reticulum stress in adipose cells.

    Science.gov (United States)

    Deng, Jingna; Liu, Shangxin; Zou, Liangqiang; Xu, Chong; Geng, Bin; Xu, Guoheng

    2012-02-24

    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.

  15. Endoplasmic reticulum stress is chronically activated in chronic pancreatitis.

    Science.gov (United States)

    Sah, Raghuwansh P; Garg, Sushil K; Dixit, Ajay K; Dudeja, Vikas; Dawra, Rajinder K; Saluja, Ashok K

    2014-10-03

    The pathogenesis of chronic pancreatitis (CP) is poorly understood. Endoplasmic reticulum (ER) stress has now been recognized as a pathogenic event in many chronic diseases. However, ER stress has not been studied in CP, although pancreatic acinar cells seem to be especially vulnerable to ER dysfunction because of their dependence on high ER volume and functionality. Here, we aim to investigate ER stress in CP, study its pathogenesis in relation to trypsinogen activation (widely regarded as the key event of pancreatitis), and explore its mechanism, time course, and downstream consequences during pancreatic injury. CP was induced in mice by repeated episodes of acute pancreatitis (AP) based on caerulein hyperstimulation. ER stress leads to activation of unfolded protein response components that were measured in CP and AP. We show sustained up-regulation of unfolded protein response components ATF4, CHOP, GRP78, and XBP1 in CP. Overexpression of GRP78 and ATF4 in human CP confirmed the experimental findings. We used novel trypsinogen-7 knock-out mice (T(-/-)), which lack intra-acinar trypsinogen activation, to clarify the relationship of ER stress to intra-acinar trypsinogen activation in pancreatic injury. Comparable activation of ER stress was seen in wild type and T(-/-) mice. Induction of ER stress occurred through pathologic calcium signaling very early in the course of pancreatic injury. Our results establish that ER stress is chronically activated in CP and is induced early in pancreatic injury through pathologic calcium signaling independent of trypsinogen activation. ER stress may be an important pathogenic mechanism in pancreatitis that needs to be explored in future studies.

  16. Altered localization of amyloid precursor protein under endoplasmic reticulum stress.

    Science.gov (United States)

    Kudo, Takashi; Okumura, Masayo; Imaizumi, Kazunori; Araki, Wataru; Morihara, Takashi; Tanimukai, Hitoshi; Kamagata, Eiichiro; Tabuchi, Nobuhiko; Kimura, Ryo; Kanayama, Daisuke; Fukumori, Akio; Tagami, Shinji; Okochi, Masayasu; Kubo, Mikiko; Tanii, Hisashi; Tohyama, Masaya; Tabira, Takeshi; Takeda, Masatoshi

    2006-06-02

    Recent reports have shown that the endoplasmic reticulum (ER) stress is relevant to the pathogenesis of Alzheimer disease. Following the amyloid cascade hypothesis, we therefore attempted to investigate the effects of ER stress on amyloid-beta peptide (Abeta) generation. In this study, we found that ER stress altered the localization of amyloid precursor protein (APP) from late compartments to early compartments of the secretory pathway, and decreased the level of Abeta 40 and Abeta 42 release by beta- and gamma-cutting. Transient transfection with BiP/GRP78 also caused a shift of APP and a reduction in Abeta secretion. It was revealed that the ER stress response facilitated binding of BiP/GRP78 to APP, thereby causing it to be retained in the early compartments apart from a location suitable for the cleavages of Abeta. These findings suggest that induction of BiP/GRP78 during ER stress may be one of the regulatory mechanisms of Abeta generation.

  17. Hyperhomocysteinemia,endoplasmic reticulum stress,and alcoholic liver injury

    Institute of Scientific and Technical Information of China (English)

    Cheng Ji; Neil Kaplowitz

    2004-01-01

    Deficiencies in vitamins or other factors (B6, B12, folic acid,betaine) and genetic disorders for the metabolism of the non-protein amino acid-homocysteine (Hcy) lead to hyperhomocysteinemia (Hhcy). Hhcy is an integral component of several disorders including cardiovascular disease, neurodegeneration, diabetes and alcoholic liver disease. Hhcy unleashes mediators of inflammation such as NFκB, IL-1β, IL-6, and IL-8, increases production of intracellular superoxide anion causing oxidative stress and reducing intracellular level of nitric oxide (NO), and induces endoplasmic reticulum (ER) stress which can explain many processes of Hcy-promoted cell injury such as apoptosis,fat accumulation, and inflammation. Animal models have played an important role in determining the biological effects of Hhcy. ER stress may also be involved in other liver diseases such as α1-antitrypsin (α1-AT) deficiency and hepatitis C and/or B virus infection. Future research should evaluate the possible potentiative effects of alcohol and hepatic virus infection on ER stress-induced liver injury, study potentially beneficial effects of lowering Hcy and preventing ER stress in alcoholic humans,and examine polymorphism of Hcy metabolizing enzymes as potential risk-factors for the development of Hhcy and liver disease.

  18. Advances in the mechanisms of atherosclerosis vulnerable plague and endoplasmic reticulum stress

    Institute of Scientific and Technical Information of China (English)

    Zhong Zhang; Ruo-Lan Huang; Ru Mo; Ling Wang; Xiao Chang; Mu-Juan Xu

    2016-01-01

    Objective:Ischemic stroke and coronary heart disease occupy the first two place of world health economic burden, atherosclerotic vulnerable plaque rupture as the common factor of these diseases, is thought to be a key target of ischemic cardiovascular and cerebrovascular disease control. Endoplasmic reticulum stress is one of the classical pathway of cell apoptosis. More and more studies have indicated that the endoplasmic reticulum stress pathway was involved in the development of atherosclerotic plaque rupture. In this paper, the three main signal pathways of endoplasmic reticulum stress, including Protein kinase RNA-like ER kinase (PERK), Activating transcription factor 6 (ATF6) and Inositol-requiring protein 1αα(IRE1α) were reviewed. The relationship between the risk factors of atherosclerosis (including hyperlipidemia, hypertension and hyperglycemia) and endoplasmic reticulum stress, and the relationship between major cellular components (macrophages, vascular endothelial cells, vascular smooth muscle cells and vascular smooth muscle cells) of vulnerable plaque and endoplasmic reticulum stress were reviewed.

  19. Targeted induction of endoplasmic reticulum stress induces cartilage pathology.

    Directory of Open Access Journals (Sweden)

    M Helen Rajpar

    2009-10-01

    Full Text Available Pathologies caused by mutations in extracellular matrix proteins are generally considered to result from the synthesis of extracellular matrices that are defective. Mutations in type X collagen cause metaphyseal chondrodysplasia type Schmid (MCDS, a disorder characterised by dwarfism and an expanded growth plate hypertrophic zone. We generated a knock-in mouse model of an MCDS-causing mutation (COL10A1 p.Asn617Lys to investigate pathogenic mechanisms linking genotype and phenotype. Mice expressing the collagen X mutation had shortened limbs and an expanded hypertrophic zone. Chondrocytes in the hypertrophic zone exhibited endoplasmic reticulum (ER stress and a robust unfolded protein response (UPR due to intracellular retention of mutant protein. Hypertrophic chondrocyte differentiation and osteoclast recruitment were significantly reduced indicating that the hypertrophic zone was expanded due to a decreased rate of VEGF-mediated vascular invasion of the growth plate. To test directly the role of ER stress and UPR in generating the MCDS phenotype, we produced transgenic mouse lines that used the collagen X promoter to drive expression of an ER stress-inducing protein (the cog mutant of thyroglobulin in hypertrophic chondrocytes. The hypertrophic chondrocytes in this mouse exhibited ER stress with a characteristic UPR response. In addition, the hypertrophic zone was expanded, gene expression patterns were disrupted, osteoclast recruitment to the vascular invasion front was reduced, and long bone growth decreased. Our data demonstrate that triggering ER stress per se in hypertrophic chondrocytes is sufficient to induce the essential features of the cartilage pathology associated with MCDS and confirm that ER stress is a central pathogenic factor in the disease mechanism. These findings support the contention that ER stress may play a direct role in the pathogenesis of many connective tissue disorders associated with the expression of mutant

  20. Klotho Ameliorates Chemically Induced Endoplasmic Reticulum (ER Stress Signaling

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    Srijita Banerjee

    2013-05-01

    Full Text Available Background: Both endoplasmic reticulum (ER stress, a fundamental cell response associated with stress-initiated unfolded protein response (UPR, and loss of Klotho, an anti-aging hormone linked to NF-κB-induced inflammation, occur in chronic metabolic diseases such as obesity and type 2 diabetes. We investigated if the loss of Klotho is causally linked to increased ER stress. Methods: We treated human renal epithelial HK-2, alveolar epithelial A549, HEK293, and SH-SH-SY5Y neuroblastoma cells with ER stress-inducing agents, thapsigargin and/or tunicamycin. Effects of overexpression or siRNA-mediated knockdown of Klotho on UPR signaling was investigated by immunoblotting and Real-time PCR. Results: Elevated Klotho levels in HK-2 cells decreased expression of ER stress markers phospho-IRE1, XBP-1s, BiP, CHOP, pJNK, and phospho-p38, all of which were elevated in response to tunicamycin and/or thapsigargin. Similar results were observed using A549 cells for XBP-1s, BiP, and CHOP in response to thapsigargin. Conversely, knockdown of Klotho in HEK 293 cells using siRNA caused further thapsigargin-induced increases in pIRE-1, XBP-1s, and BiP. Klotho overexpression in A549 cells blocked thapsigargin-induced caspase and PARP cleavage and improved cell viability. Conclusion: Our data indicate that Klotho has an important role in regulating ER stress and that loss of Klotho is causally linked to ER stress-induced apoptosis.

  1. Conserved and plant-unique strategies for overcoming endoplasmic reticulum stress.

    Science.gov (United States)

    Ruberti, Cristina; Brandizzi, Federica

    2014-01-01

    Stress caused by environmental conditions or physiological growth can lead to an accumulation of unfolded proteins in the endoplasmic reticulum (ER) causing ER stress, which in turn triggers a cytoprotective mechanism termed the unfolded protein response (UPR). Under mild-short stress conditions the UPR can restore ER functioning and cell growth, such as reducing the load of unfolded proteins through the upregulation of genes involved in protein folding and in degrading mis-folded proteins, and through autophagy activation, but it can also lead to cell death under prolonged and severe stress conditions. A diversified suite of sensors has been evolved in the eukaryotic lineages to orchestrate the UPR most likely to suit the cell's necessity to respond to the different kinds of stress in a conserved as well as species-specific manner. In plants three UPR sensors cooperate with non-identical signaling pathways: the protein kinase inositol-requiring enzyme (IRE1), the ER-membrane-associated transcription factor bZIP28, and the GTP-binding protein β1 (AGB1). In this mini-review, we show how plants differ from the better characterized metazoans and fungi, providing an overview of the signaling pathways of the UPR, and highlighting the overlapping and the peculiar roles of the different UPR branches in light of evolutionary divergences in eukaryotic kingdoms.

  2. Endoplasmic reticulum stress: key promoter of rosacea pathogenesis.

    Science.gov (United States)

    Melnik, Bodo C

    2014-12-01

    Recent scientific interest in the pathogenesis of rosacea focuses on abnormally high facial skin levels of cathelicidin and the trypsin-like serine protease kallikrein 5 (KLK5) that cleaves the cathelicidin precursor protein into the bioactive fragment LL-37, which exerts crucial proinflammatory, angiogenic and antimicrobial activities. Furthermore, increased expression of toll-like receptor 2 (TLR2) has been identified in rosacea skin supporting the participation of the innate immune system. Notably, TLRs are expressed on sensory neurons and increase neuronal excitability linking TLR signalling to the transmission of neuroinflammatory responses. It is the intention of this viewpoint to present a unifying concept that links all known clinical trigger factors of rosacea such as UV irradiation, heat, skin irritants and special foods to one converging point: enhanced endoplasmic reticulum (ER) stress that activates the unfolded protein response (UPR). ER stress via upregulation of transcription factor ATF4 increases TLR2 expression, resulting in enhanced production of cathelicidin and KLK5 mediating downstream proinflammatory, angiogenic and antimicrobial signalling. The presented concept identifies rosacea trigger factors as environmental stressors that enhance the skin's ER stress response. Exaggerated cutaneous ER stress that stimulates the TLR2-driven inflammatory response may involve sebocytes, keratinocytes, monocyte-macrophages and sensory cutaneous neurons. Finally, all antirosacea drugs are proposed to attenuate the ER stress signalling cascade at some point. Overstimulated ER stress signalling may have evolutionarily evolved as a compensatory mechanism to balance impaired vitamin D-driven LL-37-mediated antimicrobial defenses due to lower exposure of UV-B irradiation of the northern Celtic population.

  3. Transcriptional analysis implicates endoplasmic reticulum stress in bovine spongiform encephalopathy.

    Directory of Open Access Journals (Sweden)

    Yue Tang

    Full Text Available Bovine spongiform encephalopathy (BSE is a fatal, transmissible, neurodegenerative disease of cattle. To date, the disease process is still poorly understood. In this study, brain tissue samples from animals naturally infected with BSE were analysed to identify differentially regulated genes using Affymetrix GeneChip Bovine Genome Arrays. A total of 230 genes were shown to be differentially regulated and many of these genes encode proteins involved in immune response, apoptosis, cell adhesion, stress response and transcription. Seventeen genes are associated with the endoplasmic reticulum (ER and 10 of these 17 genes are involved in stress related responses including ER chaperones, Grp94 and Grp170. Western blotting analysis showed that another ER chaperone, Grp78, was up-regulated in BSE. Up-regulation of these three chaperones strongly suggests the presence of ER stress and the activation of the unfolded protein response (UPR in BSE. The occurrence of ER stress was also supported by changes in gene expression for cytosolic proteins, such as the chaperone pair of Hsp70 and DnaJ. Many genes associated with the ubiquitin-proteasome pathway and the autophagy-lysosome system were differentially regulated, indicating that both pathways might be activated in response to ER stress. A model is presented to explain the mechanisms of prion neurotoxicity using these ER stress related responses. Clustering analysis showed that the differently regulated genes found from the naturally infected BSE cases could be used to predict the infectious status of the samples experimentally infected with BSE from the previous study and vice versa. Proof-of-principle gene expression biomarkers were found to represent BSE using 10 genes with 94% sensitivity and 87% specificity.

  4. Silver nanoparticles induce endoplasmatic reticulum stress response in zebrafish

    Energy Technology Data Exchange (ETDEWEB)

    Christen, Verena [University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Capelle, Martinus [Crucell, P.O. Box 2048, NL-2301 Leiden (Netherlands); Fent, Karl, E-mail: karl.fent@fhnw.ch [University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Swiss Federal Institute of Technology Zürich, Department of Environmental Systems Science, CH-8092 Zürich (Switzerland)

    2013-10-15

    Silver nanoparticles (AgNPs) find increasing applications, and therefore humans and the environment are increasingly exposed to them. However, potential toxicological implications are not sufficiently known. Here we investigate effects of AgNPs (average size 120 nm) on zebrafish in vitro and in vivo, and compare them to human hepatoma cells (Huh7). AgNPs are incorporated in zebrafish liver cells (ZFL) and Huh7, and in zebrafish embryos. In ZFL cells AgNPs lead to induction of reactive oxygen species (ROS), endoplasmatic reticulum (ER) stress response, and TNF-α. Transcriptional alterations also occur in pro-apoptotic genes p53 and Bax. The transcriptional profile differed in ZFL and Huh7 cells. In ZFL cells, the ER stress marker BiP is induced, concomitant with the ER stress marker ATF-6 and spliced XBP-1 after 6 h and 24 h exposure to 0.5 g/L and 0.05 g/L AgNPs, respectively. This indicates the induction of different pathways of the ER stress response. Moreover, AgNPs induce TNF-α. In zebrafish embryos exposed to 0.01, 0.1, 1 and 5 mg/L AgNPs hatching was affected and morphological defects occurred at high concentrations. ER stress related gene transcripts BiP and Synv are significantly up-regulated after 24 h at 0.1 and 5 mg/L AgNPs. Furthermore, transcriptional alterations occurred in the pro-apoptotic genes Noxa and p21. The ER stress response was strong in ZFL cells and occurred in zebrafish embryos as well. Our data demonstrate for the first time that AgNPs lead to induction of ER stress in zebrafish. The induction of ER stress can have several consequences including the activation of apoptotic and inflammatory pathways. - Highlights: • Effects of silver nanoparticles (120 nm AgNPs) are investigated in zebrafish. • AgNPs induce all ER stress reponses in vitro in zebrafish liver cells. • AgNPs induce weak ER stress in zebrafish embryos. • AgNPs induce oxidative stress and transcripts of pro-apoptosis genes.

  5. Stress responses from the endoplasmic reticulum in cancer

    Directory of Open Access Journals (Sweden)

    Hironori eKato

    2015-04-01

    Full Text Available The endoplasmic reticulum (ER is a dynamic organelle that is essential for multiple cellular functions. During cellular stress conditions, including nutrient deprivation and dysregulation of protein synthesis, unfolded/misfolded proteins accumulate in the ER lumen, resulting in activation of the unfolded protein response (UPR. The UPR also contributes to the regulation of various intracellular signalling pathways such as calcium signalling and lipid signalling. More recently, the mitochondria-associated ER membrane (MAM, which is a site of close contact between the ER and mitochondria, has been shown to function as a platform for various intracellular stress responses including apoptotic signalling, inflammatory signalling, the autophagic response, and the UPR. Interestingly, in cancer, these signalling pathways from the ER are often dysregulated, contributing to cancer cell metabolism. Thus, the signalling pathway from the ER may be a novel therapeutic target for various cancers. In this review, we discuss recent research on the roles of stress responses from the ER, including the MAM.

  6. Chemical chaperones mitigate experimental asthma by attenuating endoplasmic reticulum stress.

    Science.gov (United States)

    Makhija, Lokesh; Krishnan, Veda; Rehman, Rakhshinda; Chakraborty, Samarpana; Maity, Shuvadeep; Mabalirajan, Ulaganathan; Chakraborty, Kausik; Ghosh, Balaram; Agrawal, Anurag

    2014-05-01

    Endoplasmic reticulum (ER) stress and consequent unfolded protein response (UPR) are important in inflammation but have been poorly explored in asthma. We used a mouse model of allergic airway inflammation (AAI) with features of asthma to understand the role of ER stress and to explore potential therapeutic effects of inhaled chemical chaperones, which are small molecules that can promote protein folding and diminish UPR. UPR markers were initially measured on alternate days during a 7-day daily allergen challenge model. UPR markers increased within 24 hours after the first allergen challenge and peaked by the third challenge, before AAI was fully established (from the fifth challenge onward). Three chemical chaperones-glycerol, trehalose, and trimethylamine-N-oxide (TMAO)-were initially administered during allergen challenge (preventive regimen). TMAO, the most effective of these chemical chaperones and 4-phenylbutyric acid, a chemical chaperone currently in clinical trials, were further tested for potential therapeutic activities after AAI was established (therapeutic regimen). Chemical chaperones showed a dose-dependent reduction in UPR markers, airway inflammation, and remodeling in both regimens. Our results indicate an early and important role of the ER stress pathway in asthma pathogenesis and show therapeutic potential for chemical chaperones.

  7. CDIP1-BAP31 Complex Transduces Apoptotic Signals from Endoplasmic Reticulum to Mitochondria under Endoplasmic Reticulum Stress

    OpenAIRE

    Takushi Namba; Fang Tian; Kiki Chu; So-Young Hwang; Kyoung Wan Yoon; Sanguine Byun; Masatsugu Hiraki; Anna Mandinova; Sam W. Lee

    2013-01-01

    Resolved endoplasmic reticulum (ER) stress response is essential for intracellular homeostatic balance, but unsettled ER stress can lead to apoptosis. Here, we show that a proapoptotic p53 target, CDIP1, acts as a key signal transducer of ER-stress-mediated apoptosis. We identify B-cell-receptor-associated protein 31 (BAP31) as an interacting partner of CDIP1. Upon ER stress, CDIP1 is induced and enhances an association with BAP31 at the ER membrane. We also show that CDIP1 binding to BAP31 i...

  8. An Involvement of Oxidative Stress in Endoplasmic Reticulum Stress and Its Associated Diseases

    Directory of Open Access Journals (Sweden)

    Bidur Bhandary

    2012-12-01

    Full Text Available The endoplasmic reticulum (ER is the major site of calcium storage and protein folding. It has a unique oxidizing-folding environment due to the predominant disulfide bond formation during the process of protein folding. Alterations in the oxidative environment of the ER and also intra-ER Ca2+ cause the production of ER stress-induced reactive oxygen species (ROS. Protein disulfide isomerases, endoplasmic reticulum oxidoreductin-1, reduced glutathione and mitochondrial electron transport chain proteins also play crucial roles in ER stress-induced production of ROS. In this article, we discuss ER stress-associated ROS and related diseases, and the current understanding of the signaling transduction involved in ER stress.

  9. A Piezoelectric Shear Stress Sensor

    Science.gov (United States)

    Kim, Taeyang; Saini, Aditya; Kim, Jinwook; Gopalarathnam, Ashok; Zhu, Yong; Palmieri, Frank L.; Wohl, Christopher J.; Jiang, Xiaoning

    2016-01-01

    In this paper, a piezoelectric sensor with a floating element was developed for shear stress measurement. The piezoelectric sensor was designed to detect the pure shear stress suppressing effects of normal stress generated from the vortex lift-up by applying opposite poling vectors to the: piezoelectric elements. The sensor was first calibrated in the lab by applying shear forces and it showed high sensitivity to shear stress (=91.3 +/- 2.1 pC/Pa) due to the high piezoelectric coefficients of PMN-33%PT (d31=-1330 pC/N). The sensor also showed almost no sensitivity to normal stress (less than 1.2 pC/Pa) because of the electromechanical symmetry of the device. The usable frequency range of the sensor is 0-800 Hz. Keywords: Piezoelectric sensor, shear stress, floating element, electromechanical symmetry

  10. Homocysteine inhibits hepatocyte proliferation via endoplasmic reticulum stress.

    Directory of Open Access Journals (Sweden)

    Xue Yu

    Full Text Available Homocysteine is an independent risk factor for coronary, cerebral, and peripheral vascular diseases. Recent studies have shown that levels of homocysteine are elevated in patients with impaired hepatic function, but the precise role of homocysteine in the development of hepatic dysfunction is unclear. In this study, we examined the effect of homocysteine on hepatocyte proliferation in vitro. Our results demonstrated that homocysteine inhibited hepatocyte proliferation by up-regulating protein levels of p53 as well as mRNA and protein levels of p21(Cip1 in primary cultured hepatocytes. Homocysteine induced cell growth arrest in p53-positive hepatocarcinoma cell line HepG2, but not in p53-null hepatocarcinoma cell line Hep3B. A p53 inhibitor pifithrin-α inhibited the expression of p21(Cip1 and attenuated homocysteine-induced cell growth arrest. Homocysteine induced TRB3 expression via endoplasmic reticulum stress pathway, resulting in Akt dephosphorylation. Knock-down of endogenous TRB3 significantly suppressed the inhibitory effect of homocysteine on cell proliferation and the phosphorylation of Akt. LiCl reversed homocysteine-mediated cell growth arrest by inhibiting TRB3-mediated Akt dephosphorylation. These results demonstrate that both TRB3 and p21(Cip1 are critical molecules in the homocysteine signaling cascade and provide a mechanistic explanation for impairment of liver regeneration in hyperhomocysteinemia.

  11. Sodium Butyrate Induces Endoplasmic Reticulum Stress and Autophagy in Colorectal Cells: Implications for Apoptosis

    OpenAIRE

    Jintao Zhang; Man Yi; Longying Zha; Siqiang Chen; Zhijia Li; Cheng Li; Mingxing Gong; Hong Deng; Xinwei Chu; Jiehua Chen; Zheqing Zhang; Limei Mao; Suxia Sun

    2016-01-01

    Purpose Butyrate, a short-chain fatty acid derived from dietary fiber, inhibits proliferation and induces cell death in colorectal cancer cells. However, clinical trials have shown mixed results regarding the anti-tumor activities of butyrate. We have previously shown that sodium butyrate increases endoplasmic reticulum stress by altering intracellular calcium levels, a well-known autophagy trigger. Here, we investigated whether sodium butyrate-induced endoplasmic reticulum stress mediated au...

  12. Placental endoplasmic reticulum stress and acidosis: relevant aspects in gestational diabetes.

    Science.gov (United States)

    Jawerbaum, Alicia

    2016-10-01

    In this issue, Yung and colleagues (doi: 10.1007/s00125-016-4040-2 ) report endoplasmic reticulum stress in the placenta of patients with gestational diabetes mellitus. With the use of a trophoblast-like cell line, these authors identify putative mechanisms involved in, and treatments to prevent the induction of endoplasmic reticulum stress. Here, the relevance and possible implications of these findings and areas for further research are discussed.

  13. Acoustic/Magnetic Stress Sensor

    Science.gov (United States)

    Heyman, J. S.; Namkung, M.

    1986-01-01

    High-resolution sensor fast, portable, does not require permanent bonding to structure. Sensor measures nondestructively type (compressive or tensile) and magnitude of stresses and stress gradients present in class of materials. Includes precise high-resolution acoustic interferometer, sending acoustic transducer, receiving acoustic transducer, electromagnet coil and core, power supply, and magnetic-field-measuring device such as Hall probe. This measurement especially important for construction and applications where steel is widely used. Sensor useful especially for nondestructive evaluation of stress in steel members because of portability, rapid testing, and nonpermanent installation.

  14. Involvement of endoplasmic reticulum stress in the necroptosis of microglia/macrophages after spinal cord injury.

    Science.gov (United States)

    Fan, H; Tang, H-B; Kang, J; Shan, L; Song, H; Zhu, K; Wang, J; Ju, G; Wang, Y-Z

    2015-12-17

    Microglia/macrophages play a crucial role in inflammation after spinal cord injury (SCI). Although extensive studies have been performed on the mechanisms of microglia/macrophage activation and recruitment, how microglia/macrophages are eliminated remains unclear. In the present study, we observed a high-level expression of mixed lineage kinase domain-like protein (MLKL), a key molecule in the execution of necroptosis, in microglia/macrophages after SCI in mice. In vivo PI-labeling and Necrostatin-1 treatment confirmed the necroptosis of microglia/macrophages. Interestingly, our electronic microscopic (EM) study revealed that MLKL localized not only at the membrane but also on the endoplasmic reticulum (ER) of necroptotic microglia/macrophages. Furthermore, receptor-interacting protein 3 (RIP3), another necrosome component, was also found on the ER of necroptotic microglia/macrophages. And Glucose-regulated protein 78 (GRP78), an ER stress sensor, was up-regulated in MLKL-positive microglia/macrophages after SCI, suggesting a possible link between necroptosis and ER stress. In vitro, oxygen-glucose deprivation (OGD) stress induced ER stress and necroptosis in microglia. Inhibiting ER stress by 4-phenylbutyrate (4-PBA) significantly blocked the OGD-induced necroptosis of microglia. In the end, our data showed that, GRP78 and phosphorylated MLKL were co-expressed by the microglia/macrophages in the injured human spinal cord. Taken together, these results suggested that microglia/macrophages undergo an ER-stress involved necroptosis after SCI, implying that ER stress and necroptosis could be manipulated for modulating inflammation post-SCI.

  15. Protective effect of mild endoplasmic reticulum stress on radiation-induced bystander effects in hepatocyte cells

    Science.gov (United States)

    Xie, Yuexia; Ye, Shuang; Zhang, Jianghong; He, Mingyuan; Dong, Chen; Tu, Wenzhi; Liu, Peifeng; Shao, Chunlin

    2016-01-01

    Radiation-induced bystander effect (RIBE) has important implications for secondary cancer risk assessment during cancer radiotherapy, but the defense and self-protective mechanisms of bystander normal cells are still largely unclear. The present study found that micronuclei (MN) formation could be induced in the non-irradiated HL-7702 hepatocyte cells after being treated with the conditioned medium from irradiated hepatoma HepG2 cells under either normoxia or hypoxia, where the ratio of the yield of bystander MN induction to the yield of radiation-induced MN formation under hypoxia was much higher than that of normoxia. Nonetheless, thapsigargin induced endoplasmic reticulum (ER) stress and dramatically suppressed this bystander response manifested as the decrease of MN and apoptosis inductions. Meanwhile, the interference of BiP gene, a major ER chaperone, amplified the detrimental RIBE. More precisely, thapsigargin provoked ER sensor of PERK to initiate an instantaneous and moderate ER stress thus defensed the hazard form RIBE, while BiP depletion lead to persistently destroyed homeostasis of ER and exacerbated cell injury. These findings provide new insights that the mild ER stress through BiP-PERK-p-eIF2α signaling pathway has a profound role in protecting cellular damage from RIBE and hence may decrease the potential secondary cancer risk after cancer radiotherapy. PMID:27958308

  16. Ultrasonic Dynamic Vector Stress Sensor

    Science.gov (United States)

    Heyman, Joseph S.; Froggatt, Mark

    1992-01-01

    Stress inferred from measurements in specimens rather than in bonded gauges. Ultrasonic dynamic vector stress sensor (UDVSS) measures changes in dynamic directional stress occurring in material or structure at location touched by device when material or structure put under cyclic load. Includes phase-locked loop, synchronous amplifier, and contact probe. Useful among manufacturers of aerospace and automotive structures for stress testing and evaluation of designs.

  17. Obesity-Induced Endoplasmic Reticulum Stress Causes Lung Endothelial Dysfunction and Promotes Acute Lung Injury.

    Science.gov (United States)

    Shah, Dilip; Romero, Freddy; Guo, Zhi; Sun, Jianxin; Li, Jonathan; Kallen, Caleb B; Naik, Ulhas P; Summer, Ross

    2017-08-01

    Obesity is a significant risk factor for acute respiratory distress syndrome. The mechanisms underlying this association are unknown. We recently showed that diet-induced obese mice exhibit pulmonary vascular endothelial dysfunction, which is associated with enhanced susceptibility to LPS-induced acute lung injury. Here, we demonstrate that lung endothelial dysfunction in diet-induced obese mice coincides with increased endoplasmic reticulum (ER) stress. Specifically, we observed enhanced expression of the major sensors of misfolded proteins, including protein kinase R-like ER kinase, inositol-requiring enzyme α, and activating transcription factor 6, in whole lung and in primary lung endothelial cells isolated from diet-induced obese mice. Furthermore, we found that primary lung endothelial cells exposed to serum from obese mice, or to saturated fatty acids that mimic obese serum, resulted in enhanced expression of markers of ER stress and the induction of other biological responses that typify the lung endothelium of diet-induced obese mice, including an increase in expression of endothelial adhesion molecules and a decrease in expression of endothelial cell-cell junctional proteins. Similar changes were observed in lung endothelial cells and in whole-lung tissue after exposure to tunicamycin, a compound that causes ER stress by blocking N-linked glycosylation, indicating that ER stress causes endothelial dysfunction in the lung. Treatment with 4-phenylbutyric acid, a chemical protein chaperone that reduces ER stress, restored vascular endothelial cell expression of adhesion molecules and protected against LPS-induced acute lung injury in diet-induced obese mice. Our work indicates that fatty acids in obese serum induce ER stress in the pulmonary endothelium, leading to pulmonary endothelial cell dysfunction. Our work suggests that reducing protein load in the ER of pulmonary endothelial cells might protect against acute respiratory distress syndrome in obese

  18. Endoplasmic reticulum stress contributes to Helicobacter pylori VacA-induced apoptosis.

    Directory of Open Access Journals (Sweden)

    Yuko Akazawa

    Full Text Available Vacuolating cytotoxin A (VacA is one of the important virulence factors produced by H. pylori. VacA induces apoptotic cell death, which is potentiated by ammonia. VacA also causes cell death by mitochondrial damage, via signaling pathways that are not fully defined. Our aim was to determine whether endoplasmic reticulum (ER stress is associated with VacA-induced mitochondrial dysfunction and apoptosis. We found that C/EBP homologous protein (CHOP, a key signaling protein of ER stress-induced apoptosis, was transcriptionally up-regulated following incubation of gastric epithelial cells with VacA. The effect of VacA on CHOP induction was significantly enhanced by co-incubation with ammonium chloride. Phosphorylation of eukaryotic initiation factor 2 (eIF2-alpha, which is known to occur downstream of the ER stress sensor PKR-like ER-localized eIF2-alpha kinase (PERK and to regulate CHOP expression, was also observed following incubation with VacA in the presence of ammonium chloride. Knockdown of CHOP by siRNA resulted in inhibition of VacA-induced apoptosis. Further studies showed that silencing of the PERK gene with siRNA attenuated VacA-mediated phosphorylation of eIF2-alpha, CHOP induction, expression of BH3-only protein Bim and Bax activation, and cell death induced by VacA with ammonium chloride, indicating that ER stress may lead to mitochondrial dysfunction during VacA-induced toxicity. Activation of ER stress and up-regulation of BH3-only proteins were also observed in human H. pylori-infected gastric mucosa. Collectively, this study reveals a possible association between VacA-induced apoptosis in gastric epithelial cells, and activation of ER stress in H. pylori-positive gastric mucosa.

  19. Alginate Oligosaccharide Prevents Acute Doxorubicin Cardiotoxicity by Suppressing Oxidative Stress and Endoplasmic Reticulum-Mediated Apoptosis.

    Science.gov (United States)

    Guo, Jun-Jie; Ma, Lei-Lei; Shi, Hong-Tao; Zhu, Jian-Bing; Wu, Jian; Ding, Zhi-Wen; An, Yi; Zou, Yun-Zeng; Ge, Jun-Bo

    2016-12-20

    Doxorubicin (DOX) is a highly potent chemotherapeutic agent, but its usage is limited by dose-dependent cardiotoxicity. DOX-induced cardiotoxicity involves increased oxidative stress and activated endoplasmic reticulum-mediated apoptosis. Alginate oligosaccharide (AOS) is a non-immunogenic, non-toxic and biodegradable polymer, with anti-oxidative, anti-inflammatory and anti-endoplasmic reticulum stress properties. The present study examined whether AOS pretreatment could protect against acute DOX cardiotoxicity, and the underlying mechanisms focused on oxidative stress and endoplasmic reticulum-mediated apoptosis. We found that AOS pretreatment markedly increased the survival rate of mice insulted with DOX, improved DOX-induced cardiac dysfunction and attenuated DOX-induced myocardial apoptosis. AOS pretreatment mitigated DOX-induced cardiac oxidative stress, as shown by the decreased expressions of gp91 (phox) and 4-hydroxynonenal (4-HNE). Moreover, AOS pretreatment significantly decreased the expression of Caspase-12, C/EBP homologous protein (CHOP) (markers for endoplasmic reticulum-mediated apoptosis) and Bax (a downstream molecule of CHOP), while up-regulating the expression of anti-apoptotic protein Bcl-2. Taken together, these findings identify AOS as a potent compound that prevents acute DOX cardiotoxicity, at least in part, by suppression of oxidative stress and endoplasmic reticulum-mediated apoptosis.

  20. Endoplasmic reticulum stress in pathogenesis of diabetic retinopathy and effect of calcium dobesilate

    Institute of Scientific and Technical Information of China (English)

    Yu-Min Gui; Ming Zhao; Jie Ding

    2016-01-01

    Objective:To study the mechanism of endoplasmic reticulum stress in the pathogenesis of diabetic retinopathy and effect of calcium dobesilate.Methods:A total of 120 diabetic retinopathy patients treated in our hospital from January 2010 to September 2015 were enrolled in this article. The serum endoplasmic reticulum stress protein and interleukin protein expression levels were analyzed before and after calcium dobesilate treatment. A total of 55 cases of healthy subjects receiving physical examination in our hospital during the same period were taken as control group.Results:Serum endoplasmic reticulum stress proteins PERK, CHOP and IRE as well as interleukin proteins IL1, IL2, IL6 and IL10 expression significantly increased, serum MDA level significantly increased while SOD, CAT and GSHpx levels significantly decreased in diabetic retinopathy patients, and compared with control group (P<0.01); after calcium dobesilate treatment, above factors were significantly restored (P<0.01).Conclusions: Diabetic retinopathy is closely related to endoplasmic reticulum stress and calcium dobesilate treatment may improve diabetic retinopathy by inhibiting endoplasmic reticulum stress.

  1. CDIP1-BAP31 Complex Transduces Apoptotic Signals from Endoplasmic Reticulum to Mitochondria under Endoplasmic Reticulum Stress

    Directory of Open Access Journals (Sweden)

    Takushi Namba

    2013-10-01

    Full Text Available Resolved endoplasmic reticulum (ER stress response is essential for intracellular homeostatic balance, but unsettled ER stress can lead to apoptosis. Here, we show that a proapoptotic p53 target, CDIP1, acts as a key signal transducer of ER-stress-mediated apoptosis. We identify B-cell-receptor-associated protein 31 (BAP31 as an interacting partner of CDIP1. Upon ER stress, CDIP1 is induced and enhances an association with BAP31 at the ER membrane. We also show that CDIP1 binding to BAP31 is required for BAP31 cleavage upon ER stress and for BAP31-Bcl-2 association. The recruitment of Bcl-2 to the BAP31-CDIP1 complex, as well as CDIP1-dependent truncated Bid (tBid and caspase-8 activation, contributes to BAX oligomerization. Genetic knockout of CDIP1 in mice leads to impaired response to ER-stress-mediated apoptosis. Altogether, our data demonstrate that the CDIP1/BAP31-mediated regulation of mitochondrial apoptosis pathway represents a mechanism for establishing an ER-mitochondrial crosstalk for ER-stress-mediated apoptosis signaling.

  2. CDIP1-BAP31 complex transduces apoptotic signals from endoplasmic reticulum to mitochondria under endoplasmic reticulum stress.

    Science.gov (United States)

    Namba, Takushi; Tian, Fang; Chu, Kiki; Hwang, So-Young; Yoon, Kyoung Wan; Byun, Sanguine; Hiraki, Masatsugu; Mandinova, Anna; Lee, Sam W

    2013-10-31

    Resolved endoplasmic reticulum (ER) stress response is essential for intracellular homeostatic balance, but unsettled ER stress can lead to apoptosis. Here, we show that a proapoptotic p53 target, CDIP1, acts as a key signal transducer of ER-stress-mediated apoptosis. We identify B-cell-receptor-associated protein 31 (BAP31) as an interacting partner of CDIP1. Upon ER stress, CDIP1 is induced and enhances an association with BAP31 at the ER membrane. We also show that CDIP1 binding to BAP31 is required for BAP31 cleavage upon ER stress and for BAP31-Bcl-2 association. The recruitment of Bcl-2 to the BAP31-CDIP1 complex, as well as CDIP1-dependent truncated Bid (tBid) and caspase-8 activation, contributes to BAX oligomerization. Genetic knockout of CDIP1 in mice leads to impaired response to ER-stress-mediated apoptosis. Altogether, our data demonstrate that the CDIP1/BAP31-mediated regulation of mitochondrial apoptosis pathway represents a mechanism for establishing an ER-mitochondrial crosstalk for ER-stress-mediated apoptosis signaling.

  3. Role of endoplasmic reticulum stress in the loss of retinal ganglion cells in diabetic retinopathy

    Institute of Scientific and Technical Information of China (English)

    Liping Yang; Lemeng Wu; Dongmei Wang; Ying Li; Hongliang Dou; Mark OMTso; Zhizhong Ma

    2013-01-01

    Endoplasmic reticulum stress is closely involved in the early stage of diabetic retinopathy. In the present study, a streptozotocin-induced diabetic animal model was given an intraperitoneal injection of tauroursodeoxycholic acid. Results from immunofluorescent co-localization experiments showed that both caspase-12 protein and c-Jun N-terminal kinase 1 phosphorylation levels significantly in-creased, which was associated with retinal ganglion celldeath in diabetic retinas. The C/ERB ho-mologous protein pathway directly contributed to glial reactivity, and was subsequently responsible for neuronal loss and vascular abnormalities in diabetic retinopathy. Our experimental findings in-dicate that endoplasmic reticulum stress plays an important role in diabetes-induced retinal neu-ronal loss and vascular abnormalities, and that inhibiting the activation of the endoplasmic reticulum stress pathway provides effective protection against diabetic retinopathy.

  4. Osteoclast precursor differentiation by MCPIP via oxidative stress, endoplasmic reticulum stress,and autophagy

    Institute of Scientific and Technical Information of China (English)

    Kangkai Wang; Jianli Niu; Hyunbae Kim; Pappachan E. Kolattukudy

    2011-01-01

    Osteoclasts (OCs) are responsible for bone resorption in inflammatory joint diseases.Monocyte chemotactic protein-t (MCP-t) has been shown to induce differentiation of monocytes to OC precursors,but nothing is known about the underlying mechanisms.Here,we elucidate how MCPIP,induced by MCP-1,mediates this differentiation.Knockdown of MCPIP abolished MCP-1-mediated expression of OC markers,tartrate-resistant acid phosphatase,and serine protease cathepsin K.Expression of MCPIP induced p47PHOX and its membrane translocation,reactive oxygen species formation,and induction of endoplasmic reticulum (ER) stress chaperones,up-regulation of autophagy marker,Beclin-1,and lipidation of LC3,and induction of OC markers.Inhibition of oxidative stress attenuated ER stress and autophagy,and suppressed expression of OC markers.Inhibition of ER stress by a specific inhibitor or by knockdown of I REt blocked autophagy and induction of OC markers.ER stress inducers,tunicamycin and thapsigargin,induced expression of OC markers.Autophagy inhibition by 3'-methyladenine,LY294002,wortmannin or by knockdown of Beclin-1 or Atg 7 inhibited MCPIP-induced expression of OC markers.These results strongly suggest that MCP-1-induced differentiation of OC precursor cells is mediated via MCPIP-induced oxidative stress that causes ER stress leading to autophagy,revealing a novel mechanistic insight into the role of MCP-1 in OCs differentiation.

  5. Endoplasmic reticulum stress is induced in the human placenta during labour

    OpenAIRE

    Veerbeek, J.H.W.; Tissot Van Patot, M.C.; Burton, G.J.; Yung, H.W.

    2015-01-01

    This is the final published version. It originally appeared online at http://www.sciencedirect.com/science/article/pii/S0143400414008340#. Placental endoplasmic reticulum (ER) stress has been postulated in the pathophysiology of pre-eclampsia (PE) and intrauterine growth restriction (IUGR), but its activation remains elusive. Oxidative stress induced by ischaemia/hypoxia-reoxygenation activates ER stress in vitro. Here, we explored whether exposure to labour represents an in vivo model for...

  6. Fructus Broussonetae extract improves cognitive function and endoplasmic reticulum stress in Alzheimer's disease models

    Institute of Scientific and Technical Information of China (English)

    Yinghong Li; Li Hu; Zhengzhi Wu; Zhiling Yu; Meiqun Cao; Kehuan Sun; Yu Jin; Anmin Wu; Andrew CJ Huang

    2011-01-01

    This study investigated the effects and possible targets of Fructus Broussonetiae extract, a traditional Chinese medicinal herb, on a model of Alzheimer's disease induced by beta-amyloid peptide 25-35 and D-galactose. The results revealed that intragastric administration of Fructus Broussonetiae significantly increased the expression of immunoglobulin-binding protein, a key factor in the endoplasmic reticulum stress-signaling pathway in rat hippocampus. In contrast, the treatment significantly decreased expression levels of PKR-like endoplasmic reticulum kinase and C/EBP homologous protein, and substantially improved learning, memory and spatial recognition dysfunction in rats. This evidence indicates that Fructus Broussonetiae extract improves spatial learning and memory abilities in rats by affecting the regulation of hippocampal endoplasmic reticulum stress and activation of the apoptosis pathway.

  7. Management of the endoplasmic reticulum stress by activation of the heat shock response in yeast

    DEFF Research Database (Denmark)

    Hou, Jin; Tang, Hongting; Liu, Zihe

    2014-01-01

    In yeast Saccharomyces cerevisiae, accumulation of misfolded proteins in the endoplasmic reticulum (ER) causes ER stress and activates the unfolded protein response (UPR), which is mediated by Hac1p. The heat shock response (HSR) mediated by Hsf1p, mainly regulates cytosolic processes and protects...

  8. Ethanol stress impairs protein folding in the endoplasmic reticulum and activates Ire1 in Saccharomyces cerevisiae.

    Science.gov (United States)

    Miyagawa, Ken-Ichi; Ishiwata-Kimata, Yuki; Kohno, Kenji; Kimata, Yukio

    2014-01-01

    Impaired protein folding in the endoplasmic reticulum (ER) evokes the unfolded protein response (UPR), which is triggered in budding yeast, Saccharomyces cerevisiae, by the ER-located transmembrane protein Ire1. Here, we report that ethanol stress damages protein folding in the ER, causing activation of Ire1 in yeast cells. The UPR likely contributes to the ethanol tolerance of yeast cells.

  9. Survival and death of endoplasmic-reticulum-stressed cells:Role of autophagy

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Accumulation of unfolded proteins in the endoplasmic reticulum (ER) results in ER stress, which subsequently activates the unfolded protein response that induces a transcriptional program to alleviate the stress. Another cellular process that is activated during ER stress is autophagy, a mechanism of enclosing intracellular compo- nents in a double-membrane autophagosome, and then delivering it to the lysosome for degradation. Here, we discuss the role of autophagy in cellular response to ER stress, the signaling pathways linking ER stress to autophagy, and the possible implication of modulating autophagy in treatment of diseases such as cancer.

  10. A physical/psychological and biological stress combine to enhance endoplasmic reticulum stress

    Science.gov (United States)

    Mondal, Tapan Kumar; Emeny, Rebecca T.; Gao, Donghong; Ault, Jeffrey G.; Kasten-Jolly, Jane; Lawrence, David A.

    2015-01-01

    The generation of an immune response against infectious and other foreign agents is substantially modified by allostatic load, which is increased with chemical, physical and/or psychological stressors. The physical/psychological stress from cold-restraint (CR) inhibits host defense against Listeria monocytogenes (LM), due to early effects of the catecholamine norepinephrine (NE) from sympathetic nerves on β1-adrenoceptors (β1AR) of immune cells. Although CR activates innate immunity within 2 h, host defenses against bacterial growth is suppressed 2–3 days after infection (Cao and Lawrence 2002). CR enhances inducible nitric oxide synthase (iNOS) expression and NO production. The early innate activation leads to cellular reduction-oxidation (redox) changes of immune cells. Lymphocytes from CR-treated mice express fewer surface thiols. Splenic and hepatic immune cells also have fewer proteins with free thiols after CR and/or LM, and macrophages have less glutathione after the in vivo CR exposure or exposure to NE in vitro. The early induction of CR-induced oxidative stress elevates endoplasmic reticulum (ER) stress, which could interfere with keeping phagocytized LM within the phagosome or re-encapsuling LM by autophagy once they escape from the phagosome. ER stress-related proteins, such as glucose-regulated protein 78 (GRP78), have elevated expression with CR and LM. The results indicate that CR enhances the unfolded protein response (UPR), which interferes with host defenses against LM. Thus, it is postulated that increased stress, as exists with living conditions at low socioeconomic conditions, can lower host defenses against pathogens because of oxidative and ER stress processes. PMID:26391182

  11. Acrolein cytotoxicity in hepatocytes involves endoplasmic reticulum stress, mitochondrial dysfunction and oxidative stress.

    Science.gov (United States)

    Mohammad, Mohammad K; Avila, Diana; Zhang, Jingwen; Barve, Shirish; Arteel, Gavin; McClain, Craig; Joshi-Barve, Swati

    2012-11-15

    Acrolein is a common environmental, food and water pollutant and a major component of cigarette smoke. Also, it is produced endogenously via lipid peroxidation and cellular metabolism of certain amino acids and drugs. Acrolein is cytotoxic to many cell types including hepatocytes; however the mechanisms are not fully understood. We examined the molecular mechanisms underlying acrolein hepatotoxicity in primary human hepatocytes and hepatoma cells. Acrolein, at pathophysiological concentrations, caused a dose-dependent loss of viability of hepatocytes. The death was apoptotic at moderate and necrotic at high concentrations of acrolein. Acrolein exposure rapidly and dramatically decreased intracellular glutathione and overall antioxidant capacity, and activated the stress-signaling MAP-kinases JNK, p42/44 and p38. Our data demonstrate for the first time in human hepatocytes, that acrolein triggered endoplasmic reticulum (ER) stress and activated eIF2α, ATF-3 and -4, and Gadd153/CHOP, resulting in cell death. Notably, the protective/adaptive component of ER stress was not activated, and acrolein failed to up-regulate the protective ER-chaperones, GRP78 and GRP94. Additionally, exposure to acrolein disrupted mitochondrial integrity/function, and led to the release of pro-apoptotic proteins and ATP depletion. Acrolein-induced cell death was attenuated by N-acetyl cysteine, phenyl-butyric acid, and caspase and JNK inhibitors. Our data demonstrate that exposure to acrolein induces a variety of stress responses in hepatocytes, including GSH depletion, oxidative stress, mitochondrial dysfunction and ER stress (without ER-protective responses) which together contribute to acrolein toxicity. Our study defines basic mechanisms underlying liver injury caused by reactive aldehyde pollutants such as acrolein.

  12. PARM-1 is an endoplasmic reticulum molecule involved in endoplasmic reticulum stress-induced apoptosis in rat cardiac myocytes.

    Directory of Open Access Journals (Sweden)

    Koji Isodono

    Full Text Available To identify novel transmembrane and secretory molecules expressed in cardiac myocytes, signal sequence trap screening was performed in rat neonatal cardiac myocytes. One of the molecules identified was a transmembrane protein, prostatic androgen repressed message-1 (PARM-1. While PARM-1 has been identified as a gene induced in prostate in response to castration, its function is largely unknown. Our expression analysis revealed that PARM-1 was specifically expressed in hearts and skeletal muscles, and in the heart, cardiac myocytes, but not non-myocytes expressed PARM-1. Immunofluorescent staining showed that PARM-1 was predominantly localized in endoplasmic reticulum (ER. In Dahl salt-sensitive rats, high-salt diet resulted in hypertension, cardiac hypertrophy and subsequent heart failure, and significantly stimulated PARM-1 expression in the hearts, with a concomitant increase in ER stress markers such as GRP78 and CHOP. In cultured cardiac myocytes, PARM-1 expression was stimulated by proinflammatory cytokines, but not by hypertrophic stimuli. A marked increase in PARM-1 expression was observed in response to ER stress inducers such as thapsigargin and tunicamycin, which also induced apoptotic cell death. Silencing PARM-1 expression by siRNAs enhanced apoptotic response in cardiac myocytes to ER stresses. PARM-1 silencing also repressed expression of PERK and ATF6, and augmented expression of CHOP without affecting IRE-1 expression and JNK and Caspase-12 activation. Thus, PARM-1 expression is induced by ER stress, which plays a protective role in cardiac myocytes through regulating PERK, ATF6 and CHOP expression. These results suggested that PARM-1 is a novel ER transmembrane molecule involved in cardiac remodeling in hypertensive heart disease.

  13. Endoplasmic Reticulum Stress and Unfolded Protein Response in Cartilage Pathophysiology; Contributing Factors to Apoptosis and Osteoarthritis.

    Science.gov (United States)

    Hughes, Alexandria; Oxford, Alexandra E; Tawara, Ken; Jorcyk, Cheryl L; Oxford, Julia Thom

    2017-03-20

    Chondrocytes of the growth plate undergo apoptosis during the process of endochondral ossification, as well as during the progression of osteoarthritis. Although the regulation of this process is not completely understood, alterations in the precisely orchestrated programmed cell death during development can have catastrophic results, as exemplified by several chondrodystrophies which are frequently accompanied by early onset osteoarthritis. Understanding the mechanisms that underlie chondrocyte apoptosis during endochondral ossification in the growth plate has the potential to impact the development of therapeutic applications for chondrodystrophies and associated early onset osteoarthritis. In recent years, several chondrodysplasias and collagenopathies have been recognized as protein-folding diseases that lead to endoplasmic reticulum stress, endoplasmic reticulum associated degradation, and the unfolded protein response. Under conditions of prolonged endoplasmic reticulum stress in which the protein folding load outweighs the folding capacity of the endoplasmic reticulum, cellular dysfunction and death often occur. However, unfolded protein response (UPR) signaling is also required for the normal maturation of chondrocytes and osteoblasts. Understanding how UPR signaling may contribute to cartilage pathophysiology is an essential step toward therapeutic modulation of skeletal disorders that lead to osteoarthritis.

  14. Sodium Butyrate Induces Endoplasmic Reticulum Stress and Autophagy in Colorectal Cells: Implications for Apoptosis.

    Directory of Open Access Journals (Sweden)

    Jintao Zhang

    Full Text Available Butyrate, a short-chain fatty acid derived from dietary fiber, inhibits proliferation and induces cell death in colorectal cancer cells. However, clinical trials have shown mixed results regarding the anti-tumor activities of butyrate. We have previously shown that sodium butyrate increases endoplasmic reticulum stress by altering intracellular calcium levels, a well-known autophagy trigger. Here, we investigated whether sodium butyrate-induced endoplasmic reticulum stress mediated autophagy, and whether there was crosstalk between autophagy and the sodium butyrate-induced apoptotic response in human colorectal cancer cells.Human colorectal cancer cell lines (HCT-116 and HT-29 were treated with sodium butyrate at concentrations ranging from 0.5-5mM. Cell proliferation was assessed using MTT tetrazolium salt formation. Autophagy induction was confirmed through a combination of Western blotting for associated proteins, acridine orange staining for acidic vesicles, detection of autolysosomes (MDC staining, and electron microscopy. Apoptosis was quantified by flow cytometry using standard annexinV/propidium iodide staining and by assessing PARP-1 cleavage by Western blot.Sodium butyrate suppressed colorectal cancer cell proliferation, induced autophagy, and resulted in apoptotic cell death. The induction of autophagy was supported by the accumulation of acidic vesicular organelles and autolysosomes, and the expression of autophagy-associated proteins, including microtubule-associated protein II light chain 3 (LC3-II, beclin-1, and autophagocytosis-associated protein (Atg3. The autophagy inhibitors 3-methyladenine (3-MA and chloroquine inhibited sodium butyrate induced autophagy. Furthermore, sodium butyrate treatment markedly enhanced the expression of endoplasmic reticulum stress-associated proteins, including BIP, CHOP, PDI, and IRE-1a. When endoplasmic reticulum stress was inhibited by pharmacological (cycloheximide and mithramycin and genetic

  15. Acrolein cytotoxicity in hepatocytes involves endoplasmic reticulum stress, mitochondrial dysfunction and oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Mohammad, Mohammad K. [Department of Medicine, University of Louisville (United States); Alcohol Research Center, University of Louisville (United States); Avila, Diana [Department of Medicine, University of Louisville (United States); Department of Pharmacology and Toxicology, University of Louisville (United States); Alcohol Research Center, University of Louisville (United States); Zhang, Jingwen [Department of Medicine, University of Louisville (United States); Alcohol Research Center, University of Louisville (United States); Barve, Shirish [Department of Medicine, University of Louisville (United States); Department of Pharmacology and Toxicology, University of Louisville (United States); Alcohol Research Center, University of Louisville (United States); Arteel, Gavin [Department of Pharmacology and Toxicology, University of Louisville (United States); Alcohol Research Center, University of Louisville (United States); McClain, Craig [Department of Medicine, University of Louisville (United States); Department of Pharmacology and Toxicology, University of Louisville (United States); Alcohol Research Center, University of Louisville (United States); Robley Rex VAMC, Louisville, KY (United States); Joshi-Barve, Swati, E-mail: s0josh01@louisville.edu [Department of Medicine, University of Louisville (United States); Department of Pharmacology and Toxicology, University of Louisville (United States); Alcohol Research Center, University of Louisville (United States)

    2012-11-15

    Acrolein is a common environmental, food and water pollutant and a major component of cigarette smoke. Also, it is produced endogenously via lipid peroxidation and cellular metabolism of certain amino acids and drugs. Acrolein is cytotoxic to many cell types including hepatocytes; however the mechanisms are not fully understood. We examined the molecular mechanisms underlying acrolein hepatotoxicity in primary human hepatocytes and hepatoma cells. Acrolein, at pathophysiological concentrations, caused a dose-dependent loss of viability of hepatocytes. The death was apoptotic at moderate and necrotic at high concentrations of acrolein. Acrolein exposure rapidly and dramatically decreased intracellular glutathione and overall antioxidant capacity, and activated the stress-signaling MAP-kinases JNK, p42/44 and p38. Our data demonstrate for the first time in human hepatocytes, that acrolein triggered endoplasmic reticulum (ER) stress and activated eIF2α, ATF-3 and -4, and Gadd153/CHOP, resulting in cell death. Notably, the protective/adaptive component of ER stress was not activated, and acrolein failed to up-regulate the protective ER-chaperones, GRP78 and GRP94. Additionally, exposure to acrolein disrupted mitochondrial integrity/function, and led to the release of pro-apoptotic proteins and ATP depletion. Acrolein-induced cell death was attenuated by N-acetyl cysteine, phenyl-butyric acid, and caspase and JNK inhibitors. Our data demonstrate that exposure to acrolein induces a variety of stress responses in hepatocytes, including GSH depletion, oxidative stress, mitochondrial dysfunction and ER stress (without ER-protective responses) which together contribute to acrolein toxicity. Our study defines basic mechanisms underlying liver injury caused by reactive aldehyde pollutants such as acrolein. -- Highlights: ► Human primary hepatocytes and cultured cell lines are used. ► Multiple cell death signaling pathways are activated by acrolein. ► Novel finding of

  16. Calnexin deficiency and endoplasmic reticulum stress-induced apoptosis.

    Science.gov (United States)

    Zuppini, Anna; Groenendyk, Jody; Cormack, Lori A; Shore, Gordon; Opas, Michal; Bleackley, R Chris; Michalak, Marek

    2002-02-26

    In this study, we used calnexin-deficient cells to investigate the role of this protein in ER stress-induced apoptosis. We found that calnexin-deficient cells are relatively resistant to ER stress-induced apoptosis. However, caspase 3 and 8 cleavage and cytochrome c release were unchanged in these cells, indicating that ER to mitochondria "communication" during apoptotic stimulation is not affected in the absence of calnexin. The Bcl-2:Bax ratio was also not significantly changed in calnexin-deficient cells regardless of whether the ER stress was induced with thapsigargin or not. Ca(2+) homeostasis and ER morphology were unaffected by the lack of calnexin, but ER stress-induced Bap31 cleavage was significantly inhibited. Immunoprecipitation experiments revealed that Bap31 forms complexes with calnexin, which may play a role in apoptosis. The results suggest that calnexin may not play a role in the initiation of the ER stress but that the protein has an effect on later apoptotic events via its influence on Bap31 function.

  17. Type 2 diabetes mellitus induces congenital heart defects in murine embryos by increasing oxidative stress, endoplasmic reticulum stress, and apoptosis

    Science.gov (United States)

    Wu, Yanqing; Reece, E. Albert; Zhong, Jianxiang; Dong, Daoyin; Shen, Wei-Bin; Harman, Christopher R.; Yang, Peixin

    2017-01-01

    BACKGROUND Maternal type 1 and 2 diabetes mellitus are strongly associated with high rates of severe structural birth defects, including congenital heart defects. Studies in type 1 diabetic embryopathy animal models have demonstrated that cellular stress-induced apoptosis mediates the teratogenicity of maternal diabetes leading to congenital heart defect formation. However, the mechanisms underlying maternal type 2 diabetes mellitus–induced congenital heart defects remain largely unknown. OBJECTIVE We aim to determine whether oxidative stress, endoplasmic reticulum stress, and excessive apoptosis are the intracellular molecular mechanisms underlying maternal type 2 diabetes mellitus–induced congenital heart defects. STUDY DESIGN A mouse model of maternal type 2 diabetes mellitus was established by feeding female mice a high-fat diet (60% fat). After 15 weeks on the high-fat diet, the mice showed characteristics of maternal type 2 diabetes mellitus. Control dams were either fed a normal diet (10% fat) or the high-fat diet during pregnancy only. Female mice from the high-fat diet group and the 2 control groups were mated with male mice that were fed a normal diet. At E12.5, embryonic hearts were harvested to determine the levels of lipid peroxides and superoxide, endoplasmic reticulum stress markers, cleaved caspase 3 and 8, and apoptosis. E17.5 embryonic hearts were harvested for the detection of congenital heart defect formation using India ink vessel patterning and histological examination. RESULTS Maternal type 2 diabetes mellitus significantly induced ventricular septal defects and persistent truncus arteriosus in the developing heart, along with increasing oxidative stress markers, including superoxide and lipid peroxidation; endoplasmic reticulum stress markers, including protein levels of phosphorylated-protein kinase RNA-like endoplasmic reticulum kinase, phosphorylated-IRE1α, phosphorylated-eIF2α, C/EBP homologous protein, and binding immunoglobulin

  18. Stress of endoplasmic reticulum modulates differentiation and lipogenesis of human adipocytes

    Energy Technology Data Exchange (ETDEWEB)

    Koc, Michal; Mayerová, Veronika; Kračmerová, Jana [Franco-Czech Laboratory for Clinical Research on Obesity, Third Faculty of Medicine, Prague (Czech Republic); Department of Sport Medicine, Third Faculty of Medicine, Charles University in Prague, CZ-100 00 (Czech Republic); Mairal, Aline [Franco-Czech Laboratory for Clinical Research on Obesity, Third Faculty of Medicine, Prague (Czech Republic); Inserm, UMR1048, Obesity Research Laboratory, Institute of Metabolic and Cardiovascular Diseases, 31432 Toulouse, Cedex 4 (France); Mališová, Lucia; Štich, Vladimír [Franco-Czech Laboratory for Clinical Research on Obesity, Third Faculty of Medicine, Prague (Czech Republic); Department of Sport Medicine, Third Faculty of Medicine, Charles University in Prague, CZ-100 00 (Czech Republic); Langin, Dominique [Franco-Czech Laboratory for Clinical Research on Obesity, Third Faculty of Medicine, Prague (Czech Republic); Inserm, UMR1048, Obesity Research Laboratory, Institute of Metabolic and Cardiovascular Diseases, 31432 Toulouse, Cedex 4 (France); University of Toulouse, UMR1048, Paul Sabatier University, 31432 Toulouse, Cedex 4 (France); Toulouse University Hospitals, Department of Clinical Biochemistry, 31059 Toulouse, Cedex 9 (France); Rossmeislová, Lenka, E-mail: Lenka.Rossmeislova@lf3.cuni.cz [Franco-Czech Laboratory for Clinical Research on Obesity, Third Faculty of Medicine, Prague (Czech Republic); Department of Sport Medicine, Third Faculty of Medicine, Charles University in Prague, CZ-100 00 (Czech Republic)

    2015-05-08

    Background: Adipocytes are cells specialized for storage of neutral lipids. This storage capacity is dependent on lipogenesis and is diminished in obesity. The reason for the decline in lipogenic activity of adipocytes in obesity remains unknown. Recent data show that lipogenesis in liver is regulated by pathways initiated by endoplasmic reticulum stress (ERS). Thus, we aimed at investigating the effect of ERS on lipogenesis in adipose cells. Methods: Preadipocytes were isolated from subcutaneous abdominal adipose tissue from obese volunteers and in vitro differentiated into adipocytes. ERS was induced pharmacologically by thapsigargin (TG) or tunicamycin (TM). Activation of Unfolded Protein Response pathway (UPR) was monitored on the level of eIF2α phosphorylation and mRNA expression of downstream targets of UPR sensors. Adipogenic and lipogenic capacity was evaluated by Oil Red O staining, measurement of incorporation of radio-labelled glucose or acetic acid into lipids and mRNA analysis of adipogenic/lipogenic markers. Results: Exposition of adipocytes to high doses of TG (100 nM) and TM (1 μg/ml) for 1–24 h enhanced expression of several UPR markers (HSPA5, EDEM1, ATF4, XBP1s) and phosphorylation of eIF2α. This acute ERS substantially inhibited expression of lipogenic genes (DGAT2, FASN, SCD1) and glucose incorporation into lipids. Moreover, chronic exposure of preadipocytes to low dose of TG (2.5 nM) during the early phases of adipogenic conversion of preadipocytes impaired both, lipogenesis and adipogenesis. On the other hand, chronic low ERS had no apparent effect on lipogenesis in mature adipocytes. Conclusions: Acute ERS weakened a capacity of mature adipocytes to store lipids and chronic ERS diminished adipogenic potential of preadipocytes. - Highlights: • High intensity ERS inhibits lipogenic capacity of adipocytes. • ERS impairs adipogenesis when present in early stages of adipogenesis. • Lipogenesis in mature adipocytes is not

  19. CSB ablation induced apoptosis is mediated by increased endoplasmic reticulum stress response

    Science.gov (United States)

    Caputo, Manuela; Balzerano, Alessio; Arisi, Ivan; D’Onofrio, Mara; Brandi, Rossella; Bongiorni, Silvia; Brancorsini, Stefano; Frontini, Mattia; Proietti-De-Santis, Luca

    2017-01-01

    The DNA repair protein Cockayne syndrome group B (CSB) has been recently identified as a promising anticancer target. Suppression, by antisense technology, of this protein causes devastating effects on tumor cells viability, through a massive induction of apoptosis, while being non-toxic to non-transformed cells. To gain insights into the mechanisms underlying the pro-apoptotic effects observed after CSB ablation, global gene expression patterns were determined, to identify genes that were significantly differentially regulated as a function of CSB expression. Our findings revealed that response to endoplasmic reticulum stress and response to unfolded proteins were ranked top amongst the cellular processes affected by CSB suppression. The major components of the endoplasmic reticulum stress-mediated apoptosis pathway, including pro-apoptotic factors downstream of the ATF3-CHOP cascade, were dramatically up-regulated. Altogether our findings add new pieces to the understanding of CSB mechanisms of action and to the molecular basis of CS syndrome. PMID:28253359

  20. Endoplasmic Reticulum Stress and the Related Signaling Networks in Severe Asthma

    OpenAIRE

    2014-01-01

    The endoplasmic reticulum (ER) is a specialized organelle that plays a central role in biosynthesis, correct protein folding, and posttranslational modifications of secretory and membrane proteins. Loss of homeostasis in ER functions triggers the ER stress response, resulting in activation of unfolded protein response (UPR), a hallmark of many inflammatory diseases. These pathways have been reported as critical players in the pathogenesis of various pulmonary disorders, including pulmonary fi...

  1. The Endoplasmic Reticulum Stress Protein Calreticulin in Diabetic Chronic Kidney Disease

    Science.gov (United States)

    2016-07-01

    TECHNOLOGY? These studies identify a new target for the treatment of diabetic nephropathy . Studies with the NFAT inhibitor 11R- VIVIT will provide further...cells. In Aim 2, we will determine the role of CRT in mouse models of diabetic nephropathy . In year 2, we developed stably transduced HK-2 cells using...by western blot for fibronectin. 15. SUBJECT TERMS Diabetic nephropathy , calreticulin, TGF-beta, endoplasmic reticulum stress, fibrosis 16. SECURITY

  2. Disruption of calpain reduces lipotoxicity-induced cardiac injury by preventing endoplasmic reticulum stress

    Science.gov (United States)

    Li, Shengcun; Zhang, Lulu; Ni, Rui; Cao, Ting; Zheng, Dong; Xiong, Sidong; Greer, Peter A.; Fan, Guo-Chang; Peng, Tianqing

    2016-01-01

    Diabetes and obesity are prevalent in westernized countries. In both conditions, excessive fatty acid uptake by cardiomyocytes induces cardiac lipotoxicity, an important mechanism contributing to diabetic cardiomyopathy. This study investigated the effect of calpain disruption on cardiac lipotoxicity. Cardiac-specific capns1 knockout mice and their wild-type littermates (male, age of 4 weeks) were fed a high fat diet (HFD) or normal diet for 20 weeks. HFD increased body weight, altered blood lipid profiles and impaired glucose tolerance comparably in both capns1 knockout mice and their wild-type littermates. Calpain activity, cardiomyocyte cross-sectional areas, collagen deposition and triglyceride were significantly increased in HFD-fed mouse hearts, and these were accompanied by myocardial dysfunction and up-regulation of hypertrophic and fibrotic collagen genes as well as pro-inflammatory cytokines. These effects of HFD were attenuated by disruption of calpain in capns1 knockout mice. Mechanistically, deletion of capns1 in HFD-fed mouse hearts and disruption of calpain with calpain inhibitor-III, silencing of capn1, or deletion of capns1 in palmitate-stimulated cardiomyocytes prevented endoplasmic reticulum stress, apoptosis, cleavage of caspase-12 and junctophilin-2, and pro-inflammatory cytokine expression. Pharmacological inhibition of endoplasmic reticulum stress diminished palmitate-induced apoptosis and pro-inflammatory cytokine expression in cardiomyocytes. In summary, disruption of calpain prevents lipotoxicity-induced apoptosis in cardiomyocytes and cardiac injury in mice fed a HFD. The role of calpain is mediated, at least partially, through endoplasmic reticulum stress. Thus, calpain/endoplasmic reticulum stress may represent a new mechanism and potential therapeutic targets for cardiac lipotoxicity. PMID:27523632

  3. Caspase-12 is involved in stretch-induced apoptosis mediated endoplasmic reticulum stress.

    Science.gov (United States)

    Zhang, Qiang; Liu, Jianing; Chen, Shulan; Liu, Jing; Liu, Lijuan; Liu, Guirong; Wang, Fang; Jiang, Wenxin; Zhang, Caixia; Wang, Shuangyu; Yuan, Xiao

    2016-04-01

    It is well recognized that mandibular growth, which is caused by a variety of functional appliances, is considered to be the result of both neuromuscular and skeletal adaptations. Accumulating evidence has demonstrated that apoptosis plays an important role in the adaptation of skeletal muscle function. However, the underlying mechanism of apoptosis that is induced by stretch continues to be incompletely understood. Endoplasmic reticulum stress (ERS), a newly defined signaling pathway, initiates apoptosis. This study seeks to determine if caspase-12 is involved in stretch-induced apoptosis mediated endoplasmic reticulum stress in myoblast and its underlying mechanism. Apoptosis was assessed by Hochest staining, DAPI staining and annexin V binding and PI staining. ER chaperones, such as GRP78, CHOP and caspase-12, were determined by reverse transcription polymerase chain reaction (RT-PCR) and Western blot. Furthermore, caspase-12 inhibitor was used to value the mechanism of the caspase-12 pathway. Apoptosis of myoblast, which is subjected to cyclic stretch, was observed in a time-dependent manner. We found that GRP78 mRNA and protein were significantly increased and CHOP and caspase-12 were activated in myoblast that was exposed to cyclic stretch. Caspase-12 inhibition reduced stretch-induced apoptosis, and caspase-12 activated caspase-3 to induce apoptosis. We concluded that caspase-12 played an important role in stretch-induced apoptosis that is associated by endoplasmic reticulum stress by activating caspase-3.

  4. Mechanisms of Alcohol-Induced Endoplasmic Reticulum Stress and Organ Injuries

    Directory of Open Access Journals (Sweden)

    Cheng Ji

    2012-01-01

    Full Text Available Alcohol is readily distributed throughout the body in the blood stream and crosses biological membranes, which affect virtually all biological processes inside the cell. Excessive alcohol consumption induces numerous pathological stress responses, part of which is endoplasmic reticulum (ER stress response. ER stress, a condition under which unfolded/misfolded protein accumulates in the ER, contributes to alcoholic disorders of major organs such as liver, pancreas, heart, and brain. Potential mechanisms that trigger the alcoholic ER stress response are directly or indirectly related to alcohol metabolism, which includes toxic acetaldehyde and homocysteine, oxidative stress, perturbations of calcium or iron homeostasis, alterations of S-adenosylmethionine to S-adenosylhomocysteine ratio, and abnormal epigenetic modifications. Interruption of the ER stress triggers is anticipated to have therapeutic benefits for alcoholic disorders.

  5. Endoplasmic reticulum stress is induced in the human placenta during labour.

    Science.gov (United States)

    Veerbeek, J H W; Tissot Van Patot, M C; Burton, G J; Yung, H W

    2015-01-01

    Placental endoplasmic reticulum (ER) stress has been postulated in the pathophysiology of pre-eclampsia (PE) and intrauterine growth restriction (IUGR), but its activation remains elusive. Oxidative stress induced by ischaemia/hypoxia-reoxygenation activates ER stress in vitro. Here, we explored whether exposure to labour represents an in vivo model for the study of acute placental ER stress. ER stress markers, GRP78, P-eIF2α and XBP-1, were significantly higher in laboured placentas than in Caesarean-delivered controls localised mainly in the syncytiotrophoblast. The similarities to changes observed in PE/IUGR placentas suggest exposure to labour can be used to investigate induction of ER stress in pathological placentas. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  6. Endoplasmic reticulum stress contributes to acetylcholine receptor degradation by promoting endocytosis in skeletal muscle cells.

    Science.gov (United States)

    Du, Ailian; Huang, Shiqian; Zhao, Xiaonan; Zhang, Yun; Zhu, Lixun; Ding, Ji; Xu, Congfeng

    2016-01-15

    After binding by acetylcholine released from a motor neuron, a nicotinic acetylcholine receptor at the neuromuscular junction produces a localized end-plate potential, which leads to muscle contraction. Improper turnover and renewal of acetylcholine receptors contributes to the pathogenesis of myasthenia gravis. In the present study, we demonstrate that endoplasmic reticulum (ER) stress contributes to acetylcholine receptor degradation in C2C12 myocytes. We further show that ER stress promotes acetylcholine receptor endocytosis and lysosomal degradation, which was dampened by blocking endocytosis or treating with lysosome inhibitor. Knockdown of ER stress proteins inhibited acetylcholine receptor endocytosis and degradation, while rescue assay restored its endocytosis and degradation, confirming the effects of ER stress on promoting endocytosis-mediated degradation of junction acetylcholine receptors. Thus, our studies identify ER stress as a factor promoting acetylcholine receptor degradation through accelerating endocytosis in muscle cells. Blocking ER stress and/or endocytosis might provide a novel therapeutic approach for myasthenia gravis.

  7. Transcription Factor ATF4 Induces NLRP1 Inflammasome Expression during Endoplasmic Reticulum Stress.

    Directory of Open Access Journals (Sweden)

    Andrea D'Osualdo

    Full Text Available Perturbation of endoplasmic reticulum (ER homeostasis triggers the ER stress response (also known as Unfolded Protein Response, a hallmark of many pathological disorders. However the connection between ER stress and inflammation remains largely unexplored. Recent data suggest that ER stress controls the activity of inflammasomes, key signaling platforms that mediate innate immune responses. Here we report that expression of NLRP1, a core inflammasome component, is specifically up-regulated during severe ER stress conditions in human cell lines. Both IRE1α and PERK, but not the ATF6 pathway, modulate NLRP1 gene expression. Furthermore, using mutagenesis, chromatin immunoprecipitation and CRISPR-Cas9-mediated genome editing technology, we demonstrate that ATF4 transcription factor directly binds to NLRP1 promoter during ER stress. Although involved in different types of inflammatory responses, XBP-1 splicing was not required for NLRP1 induction. This study provides further evidence that links ER stress with innate.

  8. Endoplasmic reticulum stress as a primary pathogenic mechanism leading to age-related macular degeneration.

    Science.gov (United States)

    Libby, Richard T; Gould, Douglas B

    2010-01-01

    Age-related macular degeneration (AMD) is a multi-factorial disease and a leading cause of blindness. Proteomic and genetic data suggest that activation or de-repression of the alternate complement cascade of innate immunity is involved in end-stage disease. Several lines of evidence suggest that production of reactive oxygen species and chronic oxidative stress lead to protein and lipid modifications that initiate the complement cascade. Understanding the triggers of these pathogenic pathways and the site of the primary insult will be important for development of targeted therapeutics. Endoplasmic reticulum (ER) stress from misfolded mutant proteins and other sources are an important potential tributary mechanism. We propose that misfolded-protein-induced ER stress in the retinal-pigmented epithelium and/or choroid could lead to chronic oxidative stress, complement deregulation and AMD. Small molecules targeted to ER stress and oxidative stress could allow for a shift from disease treatment to disease prevention.

  9. Endoplasmic reticulum stress-induced autophagy determines the susceptibility of melanoma cells to dabrafenib

    Science.gov (United States)

    Ji, Chao; Zhang, Ziping; Chen, Lihong; Zhou, Kunli; Li, Dongjun; Wang, Ping; Huang, Shuying; Gong, Ting; Cheng, Bo

    2016-01-01

    Melanoma is one of the deadliest skin cancers and accounts for most skin-related deaths due to strong resistance to chemotherapy drugs. In the present study, we investigated the mechanisms of dabrafenib-induced drug resistance in human melanoma cell lines A375 and MEL624. Our studies support that both endoplasmic reticulum (ER) stress and autophagy were induced in the melanoma cells after the treatment with dabrafenib. In addition, ER stress-induced autophagy protects melanoma cells from the toxicity of dabrafenib. Moreover, inhibition of both ER stress and autophagy promote the sensitivity of melanoma cells to dabrafenib. Taken together, the data suggest that ER stress-induced autophagy determines the sensitivity of melanoma cells to dabrafenib. These results provide us with promising evidence that the inhibition of autophagy and ER stress could serve a therapeutic effect for the conventional dabrafenib chemotherapy. PMID:27536070

  10. Brain death is associated with endoplasmic reticulum stress and apoptosis in rat liver.

    Science.gov (United States)

    Cao, S; Wang, T; Yan, B; Lu, Y; Zhao, Y; Zhang, S

    2014-12-01

    Cell death pathways initiated by stress on the endoplasmic reticulum (ER) have been implicated in a variety of common diseases, such as ischemia/reperfusion injury, diabetes, heart disease, and neurodegenerative disorders. However, the contribution of ER stress to apoptosis and liver injury after brain death is not known. In the present study, we found that brain death induces a variety of signature ER stress markers, including ER stress-specific X box-binding protein 1 and up-regulation of glucose-regulated protein 78. Furthermore, brain death causes up-regulation of C/EBP homologous protein and caspase-12. Consistent with this, terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick-end labeling assay and transmission electron microscopy confirmed apoptosis in the liver after brain death. Taken together, the present study provides strong evidence supporting the presence and importance of ER stress and response in mediating brain death-induced apoptosis and liver injury.

  11. Tributyltin-induced endoplasmic reticulum stress and its Ca{sup 2+}-mediated mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Isomura, Midori; Kotake, Yaichiro, E-mail: yaichiro@hiroshima-u.ac.jp; Masuda, Kyoichi; Miyara, Masatsugu; Okuda, Katsuhiro; Samizo, Shigeyoshi; Sanoh, Seigo; Hosoi, Toru; Ozawa, Koichiro; Ohta, Shigeru

    2013-10-01

    Organotin compounds, especially tributyltin chloride (TBT), have been widely used in antifouling paints for marine vessels, but exhibit various toxicities in mammals. The endoplasmic reticulum (ER) is a multifunctional organelle that controls post-translational modification and intracellular Ca{sup 2+} signaling. When the capacity of the quality control system of ER is exceeded under stress including ER Ca{sup 2+} homeostasis disruption, ER functions are impaired and unfolded proteins are accumulated in ER lumen, which is called ER stress. Here, we examined whether TBT causes ER stress in human neuroblastoma SH-SY5Y cells. We found that 700 nM TBT induced ER stress markers such as CHOP, GRP78, spliced XBP1 mRNA and phosphorylated eIF2α. TBT also decreased the cell viability both concentration- and time-dependently. Dibutyltin and monobutyltin did not induce ER stress markers. We hypothesized that TBT induces ER stress via Ca{sup 2+} depletion, and to test this idea, we examined the effect of TBT on intracellular Ca{sup 2+} concentration using fura-2 AM, a Ca{sup 2+} fluorescent probe. TBT increased intracellular Ca{sup 2+} concentration in a TBT-concentration-dependent manner, and Ca{sup 2+} increase in 700 nM TBT was mainly blocked by 50 μM dantrolene, a ryanodine receptor antagonist (about 70% inhibition). Dantrolene also partially but significantly inhibited TBT-induced GRP78 expression and cell death. These results suggest that TBT increases intracellular Ca{sup 2+} concentration by releasing Ca{sup 2+} from ER, thereby causing ER stress. - Highlights: • We established that tributyltin induces endoplasmic reticulum (ER) stress. • Tributyltin induces ER stress markers in a concentration-dependent manner. • Tributyltin increases Ca{sup 2+} release from ER, thereby causing ER stress. • Dibutyltin and monobutyltin did not increase GRP78 or intracellular Ca{sup 2+}.

  12. Cis-element of the rice PDIL2-3 promoter is responsible for inducing the endoplasmic reticulum stress response.

    Science.gov (United States)

    Takahashi, Hideyuki; Wang, Shuyi; Hayashi, Shimpei; Wakasa, Yuhya; Takaiwa, Fumio

    2014-05-01

    A protein disulfide isomerase (PDI) family oxidoreductase, PDIL2-3, is involved in endoplasmic reticulum (ER) stress responses in rice. We identified a critical cis-element required for induction of the ER stress response. The activation of PDIL2-3 in response to ER stress strongly depends on the IRE1-OsbZIP50 signaling pathway.

  13. The involvement of SMILE/TMTC3 in endoplasmic reticulum stress response.

    Directory of Open Access Journals (Sweden)

    Maud Racapé

    Full Text Available BACKGROUND: The state of operational tolerance has been detected sporadically in some renal transplanted patients that stopped immunosuppressive drugs, demonstrating that allograft tolerance might exist in humans. Several years ago, a study by Brouard et al. identified a molecular signature of several genes that were significantly differentially expressed in the blood of such patients compared with patients with other clinical situations. The aim of the present study is to analyze the role of one of these molecules over-expressed in the blood of operationally tolerant patients, SMILE or TMTC3, a protein whose function is still unknown. METHODOLOGY/PRINCIPAL FINDINGS: We first confirmed that SMILE mRNA is differentially expressed in the blood of operationally tolerant patients with drug-free long term graft function compared to stable and rejecting patients. Using a yeast two-hybrid approach and a colocalization study by confocal microscopy we furthermore report an interaction of SMILE with PDIA3, a molecule resident in the endoplasmic reticulum (ER. In accordance with this observation, SMILE silencing in HeLa cells correlated with the modulation of several transcripts involved in proteolysis and a decrease in proteasome activity. Finally, SMILE silencing increased HeLa cell sensitivity to the proteasome inhibitor Bortezomib, a drug that induces ER stress via protein overload, and increased transcript expression of a stress response protein, XBP-1, in HeLa cells and keratinocytes. CONCLUSION/SIGNIFICANCE: In this study we showed that SMILE is involved in the endoplasmic reticulum stress response, by modulating proteasome activity and XBP-1 transcript expression. This function of SMILE may influence immune cell behavior in the context of transplantation, and the analysis of endoplasmic reticulum stress in transplantation may reveal new pathways of regulation in long-term graft acceptance thereby increasing our understanding of tolerance.

  14. Endoplasmic Reticulum Stress Signaling in Plant Immunity—At the Crossroad of Life and Death

    Directory of Open Access Journals (Sweden)

    Camilla J. Kørner

    2015-11-01

    Full Text Available Rapid and complex immune responses are induced in plants upon pathogen recognition. One form of plant defense response is a programmed burst in transcription and translation of pathogenesis-related proteins, of which many rely on ER processing. Interestingly, several ER stress marker genes are up-regulated during early stages of immune responses, suggesting that enhanced ER capacity is needed for immunity. Eukaryotic cells respond to ER stress through conserved signaling networks initiated by specific ER stress sensors tethered to the ER membrane. Depending on the nature of ER stress the cell prioritizes either survival or initiates programmed cell death (PCD. At present two plant ER stress sensors, bZIP28 and IRE1, have been described. Both sensor proteins are involved in ER stress-induced signaling, but only IRE1 has been additionally linked to immunity. A second branch of immune responses relies on PCD. In mammals, ER stress sensors are involved in activation of PCD, but it is unclear if plant ER stress sensors play a role in PCD. Nevertheless, some ER resident proteins have been linked to pathogen-induced cell death in plants. In this review, we will discuss the current understanding of plant ER stress signaling and its cross-talk with immune signaling.

  15. Insulin Dissociates the Effects of Liver X Receptor on Lipogenesis, Endoplasmic Reticulum Stress, and Inflammation.

    Science.gov (United States)

    Sun, Xiaowei; Haas, Mary E; Miao, Ji; Mehta, Abhiruchi; Graham, Mark J; Crooke, Rosanne M; Pais de Barros, Jean-Paul; Wang, Jian-Guo; Aikawa, Masanori; Masson, David; Biddinger, Sudha B

    2016-01-15

    Diabetes is characterized by increased lipogenesis as well as increased endoplasmic reticulum (ER) stress and inflammation. The nuclear hormone receptor liver X receptor (LXR) is induced by insulin and is a key regulator of lipid metabolism. It promotes lipogenesis and cholesterol efflux, but suppresses endoplasmic reticulum stress and inflammation. The goal of these studies was to dissect the effects of insulin on LXR action. We used antisense oligonucleotides to knock down Lxrα in mice with hepatocyte-specific deletion of the insulin receptor and their controls. We found, surprisingly, that knock-out of the insulin receptor and knockdown of Lxrα produced equivalent, non-additive effects on the lipogenic genes. Thus, insulin was unable to induce the lipogenic genes in the absence of Lxrα, and LXRα was unable to induce the lipogenic genes in the absence of insulin. However, insulin was not required for LXRα to modulate the phospholipid profile, or to suppress genes in the ER stress or inflammation pathways. These data show that insulin is required specifically for the lipogenic effects of LXRα and that manipulation of the insulin signaling pathway could dissociate the beneficial effects of LXR on cholesterol efflux, inflammation, and ER stress from the negative effects on lipogenesis.

  16. Adaptive endoplasmic reticulum stress alters cellular responses to the extracellular milieu.

    Science.gov (United States)

    Liu, Yiting; Neely, Elizabeth; Simmons, Zachary; Connor, James R

    2015-05-01

    The ability to respond to perturbations in endoplasmic reticulum (ER) function is a critical property for all cells. In the presence of chronic ER stress, the cell must adapt so that cell survival is favored or the stress may promote apoptosis. In some pathological processes, such as neurodengeneration, persistent ER stress can be tolerated for an extended period, but eventually cell death occurs. It is not known how an adaptive response converts from survival into apoptosis. To gain a better understanding of the role of adaptive ER stress in neurodegeneration, in this study, with a neuronal cell line SH-SY5Y and primary motor neuron-glia cell mixed cultures, we induced adaptive ER stress and modified the extracellular environment with physiologically relevant changes that alone did not activate ER stress. Our data demonstrate that an adaptive ER stress favored neuronal cell survival, but when cells were exposed to additional physiological insults the level of ER stress was increased, followed by activation of the caspase pathway. Our results indicate that an adaptive ER stress response could be converted to apoptosis when the external cellular milieu changed, suggesting that the conversion from prosurvival to proapoptotic pathways can be driven by the external milieu. This conversion was due at least partially to an increased level of ER stress. © 2015 Wiley Periodicals, Inc.

  17. Angiogenin Mediates Cell-Autonomous Translational Control under Endoplasmic Reticulum Stress and Attenuates Kidney Injury.

    Science.gov (United States)

    Mami, Iadh; Bouvier, Nicolas; El Karoui, Khalil; Gallazzini, Morgan; Rabant, Marion; Laurent-Puig, Pierre; Li, Shuping; Tharaux, Pierre-Louis; Beaune, Philippe; Thervet, Eric; Chevet, Eric; Hu, Guo-Fu; Pallet, Nicolas

    2016-03-01

    Endoplasmic reticulum (ER) stress is involved in the pathophysiology of kidney disease and aging, but the molecular bases underlying the biologic outcomes on the evolution of renal disease remain mostly unknown. Angiogenin (ANG) is a ribonuclease that promotes cellular adaptation under stress but its contribution to ER stress signaling remains elusive. In this study, we investigated the ANG-mediated contribution to the signaling and biologic outcomes of ER stress in kidney injury. ANG expression was significantly higher in samples from injured human kidneys than in samples from normal human kidneys, and in mouse and rat kidneys, ANG expression was specifically induced under ER stress. In human renal epithelial cells, ER stress induced ANG expression in a manner dependent on the activity of transcription factor XBP1, and ANG promoted cellular adaptation to ER stress through induction of stress granules and inhibition of translation. Moreover, the severity of renal lesions induced by ER stress was dramatically greater in ANG knockout mice (Ang(-/-)) mice than in wild-type mice. These results indicate that ANG is a critical mediator of tissue adaptation to kidney injury and reveal a physiologically relevant ER stress-mediated adaptive translational control mechanism.

  18. Endoplasmic reticulum (ER) stress-suppressive compounds from scrap cultivation beds of the mushroom Hericium erinaceum.

    Science.gov (United States)

    Ueda, Keiko; Kodani, Shinya; Kubo, Masakazu; Masuno, Kazuhiko; Sekiya, Atsushi; Nagai, Kaoru; Kawagishi, Hirokazu

    2009-08-01

    Four compounds were isolated from scrap cultivation beds of the mushroom, Hericium erinaceum. Compounds 1-4 were identified as methyl 4-hydroxy-3-(3-methylbutanoyl) benzoate, 2-chloro-1,3-dimethoxy-5-methylbenzene, methyl 4-chloro-3,5-dimethoxybenzoate, and 4-chloro-3,5-dimethoxybenzaldehyde by an interpretation of the NMR and MS data, respectively. This is the first reported isolation of 1 from a natural source. All the compounds showed protective activity against endoplasmic reticulum stress-dependent cell death.

  19. Lipotoxicity-Induced PRMT1 Exacerbates Mesangial Cell Apoptosis via Endoplasmic Reticulum Stress

    Directory of Open Access Journals (Sweden)

    Min-Jung Park

    2017-07-01

    Full Text Available Lipotoxicity-induced mesangial cell apoptosis is implicated in the exacerbation of diabetic nephropathy (DN. Protein arginine methyltransferases (PRMTs have been known to regulate a variety of biological functions. Recently, it was reported that PRMT1 expression is increased in proximal tubule cells under diabetic conditions. However, their roles in mesangial cells remain unexplored. Thus, we examined the pathophysiological roles of PRMTs in mesangial cell apoptosis. Treatment with palmitate, which mimics cellular lipotoxicity, induced mesangial cell apoptosis via protein kinase RNA-like endoplasmic reticulum kinase (PERK and ATF6-mediated endoplasmic reticulum (ER stress signaling. Palmitate treatment increased PRMT1 expression and activity in mesangial cells as well. Moreover, palmitate-induced ER stress activation and mesangial cell apoptosis was diminished by PRMT1 knockdown. In the mice study, high fat diet-induced glomerular apoptosis was attenuated in PRMT1 haploinsufficient mice. Together, these results provide evidence that lipotoxicity-induced PRMT1 expression promotes ER stress-mediated mesangial cell apoptosis. Strategies to regulate PRMT1 expression or activity could be used to prevent the exacerbation of DN.

  20. Methods for monitoring endoplasmic reticulum stress and the unfolded protein response.

    LENUS (Irish Health Repository)

    Samali, Afshin

    2010-01-01

    The endoplasmic reticulum (ER) is the site of folding of membrane and secreted proteins in the cell. Physiological or pathological processes that disturb protein folding in the endoplasmic reticulum cause ER stress and activate a set of signaling pathways termed the Unfolded Protein Response (UPR). The UPR can promote cellular repair and sustained survival by reducing the load of unfolded proteins through upregulation of chaperones and global attenuation of protein synthesis. Research into ER stress and the UPR continues to grow at a rapid rate as many new investigators are entering the field. There are also many researchers not working directly on ER stress, but who wish to determine whether this response is activated in the system they are studying: thus, it is important to list a standard set of criteria for monitoring UPR in different model systems. Here, we discuss approaches that can be used by researchers to plan and interpret experiments aimed at evaluating whether the UPR and related processes are activated. We would like to emphasize that no individual assay is guaranteed to be the most appropriate one in every situation and strongly recommend the use of multiple assays to verify UPR activation.

  1. Z α-1 antitrypsin deficiency and the endoplasmic reticulum stress response

    Institute of Scientific and Technical Information of China (English)

    Catherine; M; Greene; Noel; G; McElvaney

    2010-01-01

    The serine proteinase inhibitor α-1 antitrypsin(AAT) is produced principally by the liver at the rate of 2 g/d.It is secreted into the circulation and provides an antiprotease protective screen throughout the body but most importantly in the lung,where it can neutralise the activity of the serine protease neutrophil elastase.Mutations leading to def iciency in AAT are associated with liver and lung disease.The most notable is the Z AAT mutation,which encodes a misfolded variant of the AAT protein in which the glutamic acid at position 342 is replaced by a lysine.More than 95% of all individuals with AAT def iciency carry at least one Z allele.ZAAT protein is not secreted effectively and accumulates intracellularly in the endoplasmic reticulum(ER) of hepatocytes and other AAT-producing cells.This results in a loss of function associated with decreased circulating and intrapulmonary levels of AAT.However,the misfolded protein acquires a toxic gain of function that impacts on the ER.A major function of the ER is to ensure correct protein folding.ZAAT interferes with this function and promotes ER stress responses and inflammation.Here the signalling pathways activated during ER stress in response to accumulation of ZAAT are described and therapeutic strategies that can potentially relieve ER stress are discussed.

  2. Respiratory metabolism and calorie restriction relieve persistent endoplasmic reticulum stress induced by calcium shortage in yeast.

    Science.gov (United States)

    Busti, Stefano; Mapelli, Valeria; Tripodi, Farida; Sanvito, Rossella; Magni, Fulvio; Coccetti, Paola; Rocchetti, Marcella; Nielsen, Jens; Alberghina, Lilia; Vanoni, Marco

    2016-06-16

    Calcium homeostasis is crucial to eukaryotic cell survival. By acting as an enzyme cofactor and a second messenger in several signal transduction pathways, the calcium ion controls many essential biological processes. Inside the endoplasmic reticulum (ER) calcium concentration is carefully regulated to safeguard the correct folding and processing of secretory proteins. By using the model organism Saccharomyces cerevisiae we show that calcium shortage leads to a slowdown of cell growth and metabolism. Accumulation of unfolded proteins within the calcium-depleted lumen of the endoplasmic reticulum (ER stress) triggers the unfolded protein response (UPR) and generates a state of oxidative stress that decreases cell viability. These effects are severe during growth on rapidly fermentable carbon sources and can be mitigated by decreasing the protein synthesis rate or by inducing cellular respiration. Calcium homeostasis, protein biosynthesis and the unfolded protein response are tightly intertwined and the consequences of facing calcium starvation are determined by whether cellular energy production is balanced with demands for anabolic functions. Our findings confirm that the connections linking disturbance of ER calcium equilibrium to ER stress and UPR signaling are evolutionary conserved and highlight the crucial role of metabolism in modulating the effects induced by calcium shortage.

  3. Impact of high cholesterol and endoplasmic reticulum stress on metabolic diseases: An updated mini-review

    Directory of Open Access Journals (Sweden)

    Erdi Sozen

    2017-08-01

    Full Text Available Endoplasmic reticulum (ER is the major site of protein folding and calcium storage. Beside the role of ER in protein homeostasis, it controls the cholesterol production and lipid-membrane biosynthesis as well as surviving and cell death signaling mechanisms in the cell. It is well-documented that elevated plasma cholesterol induces adverse effects in cardiovascular diseases (CVDs, liver disorders, such as non-alcoholic fatty liver disease (NAFLD, non-alcoholic steatosis hepatitis (NASH, and metabolic diseases which are associated with oxidative and ER stress. Recent animal model and human studies have showed high cholesterol and ER stress as an emerging factors involved in the development of many metabolic diseases. In this review, we will summarize the crucial effects of hypercholesterolemia and ER stress response in the pathogenesis of CVDs, NAFLD/NASH, diabetes and obesity which are major health problems in western countries.

  4. Pekinenin E Inhibits the Growth of Hepatocellular Carcinoma by Promoting Endoplasmic Reticulum Stress Mediated Cell Death

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    Lu Fan

    2017-06-01

    Full Text Available Hepatocellular carcinoma (HCC is a malignant primary liver cancer with poor prognosis. In the present study, we report that pekinenin E (PE, a casbane diterpenoid derived from the roots of Euphorbia pekinensis, has a strong antitumor activity against human HCC cells both in vitro and in vivo. PE suppressed the growth of human HCC cells Hep G2 and SMMC-7721. In addition, PE-mediated endoplasmic reticulum (ER stress caused increasing expressions of C/EBP homologous protein (CHOP, leading to apoptosis in HCC cells both in vitro and in vivo. Inhibition of ER stress with CHOP small interfering RNA or 4-phenyl-butyric acid partially reversed PE-induced cell death. Furthermore, PE induced S cell cycle arrest, which could also be partially reversed by CHOP knockdown. In all, these findings suggest that PE causes ER stress-associated cell death and cell cycle arrest, and it may serve as a potent agent for curing human HCC.

  5. Melatonin Induces Anti-Inflammatory Effects to Play a Protective Role via Endoplasmic Reticulum Stress in Acute Pancreatitis.

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    Chen, Yina; Zhang, Jie; Zhao, Qian; Chen, Qinfen; Sun, Yangjie; Jin, Yin; Wu, Jiansheng

    2016-01-01

    Melatonin, which is mainly secreted by the pineal gland and released into blood, has anti-inflammatory properties in acute pancreatitis. Many studies show that melatonin can relieve inflammation in taurocholate-induced acute pancreatitis. However, the mechanisms of its anti-inflammatory effects are still undefined, especially the relationship between melatonin and endoplasmic reticulum stress. We explored the anti-inflammatory activity of melatonin in AR42J and rat models. The CCK-8 assay was used to assess effects of melatonin on AR42J cell viability. Inflammatory degree and the expressions of endoplasmic reticulum stress related molecules were examined by quantitative RT-PCR and western blotting. The degree of inflammation in the tissue was also accessed by pathological grading. Finally, we used the western blotting method to verify apoptosis and autophagy. Endoplasmic reticulum stress was obviously activated in early stage inflammation in AR42J and rat models. Melatonin could induce anti-inflammatory effects via endoplasmic reticulum stress. Melatonin significantly inhibited inflammatory cytokines and the expression of ERS-related molecules. Finally, it played a protective role by promoting apoptosis and autophagy of the cells, which were damaged in the process of inflammatory reaction. Melatonin induces anti-inflammatory effects via endoplasmic reticulum stress in acute pancreatitis to play a protective role. © 2016 The Author(s) Published by S. Karger AG, Basel.

  6. Melatonin Induces Anti-Inflammatory Effects to Play a Protective Role via Endoplasmic Reticulum Stress in Acute Pancreatitis

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    Yina Chen

    2016-12-01

    Full Text Available Background/Aims: Melatonin, which is mainly secreted by the pineal gland and released into blood, has anti-inflammatory properties in acute pancreatitis. Many studies show that melatonin can relieve inflammation in taurocholate-induced acute pancreatitis. However, the mechanisms of its anti-inflammatory effects are still undefined, especially the relationship between melatonin and endoplasmic reticulum stress. We explored the anti-inflammatory activity of melatonin in AR42J and rat models. Methods: The CCK-8 assay was used to assess effects of melatonin on AR42J cell viability. Inflammatory degree and the expressions of endoplasmic reticulum stress related molecules were examined by quantitative RT-PCR and western blotting. The degree of inflammation in the tissue was also accessed by pathological grading. Finally, we used the western blotting method to verify apoptosis and autophagy. Results: Endoplasmic reticulum stress was obviously activated in early stage inflammation in AR42J and rat models. Melatonin could induce anti-inflammatory effects via endoplasmic reticulum stress. Melatonin significantly inhibited inflammatory cytokines and the expression of ERS-related molecules. Finally, it played a protective role by promoting apoptosis and autophagy of the cells, which were damaged in the process of inflammatory reaction. Conclusion: Melatonin induces anti-inflammatory effects via endoplasmic reticulum stress in acute pancreatitis to play a protective role.

  7. Neuroprotective effects of atorvastatin against cerebral ischemia/reperfusion injury through the inhibition of endoplasmic reticulum stress

    Institute of Scientific and Technical Information of China (English)

    Jian-wen Yang; Zhi-ping Hu

    2015-01-01

    Cerebral ischemia triggers secondary ischemia/reperfusion injury and endoplasmic reticulum stress initiates cell apoptosis. However, the regulatory mechanism of the signaling pathway remains unclear. We hypothesize that the regulatory mechanisms are mediated by the protein kinase-like endoplasmic reticulum kinase/eukaryotic initiation factor 2α in the endoplasmic reticulum stress signaling pathway. To verify this hypothesis, we occluded the middle cere-bral artery in rats to establish focal cerebral ischemia/reperfusion model. Results showed that the expression levels of protein kinase-like endoplasmic reticulum kinase and caspase-3, as well as the phosphorylation of eukaryotic initiation factor 2α, were increased after ischemia/reperfusion. Administration of atorvastatin decreased the expression of protein kinase-like endoplasmic reticulum kinase, caspase-3 and phosphorylated eukaryotic initiation factor 2α, reduced the infarct volume and improved ultrastructure in the rat brain. After salubrinal, the speciifc inhibitor of phosphorylated eukaryotic initiation factor 2α was given into the rats in-tragastrically, the expression levels of caspase-3 and phosphorylated eukaryotic initiation factor 2α in the were decreased, a reduction of the infarct volume and less ultrastructural damage were observed than the untreated, ischemic brain. However, salubrinal had no impact on the expression of protein kinase-like endoplasmic reticulum kinase. Experimental ifndings indi-cate that atorvastatin inhibits endoplasmic reticulum stress and exerts neuroprotective effects. The underlying mechanisms of attenuating ischemia/reperfusion injury are associated with the protein kinase-like endoplasmic reticulum kinase/eukaryotic initiation factor 2α/caspase-3 pathway.

  8. Cytokines downregulate the sarcoendoplasmic reticulum pump Ca2+ ATPase 2b and deplete endoplasmic reticulum Ca2+, leading to induction of endoplasmic reticulum stress in pancreatic beta-cells

    DEFF Research Database (Denmark)

    Cardozo, Alessandra K; Ortis, Fernanda; Storling, Joachim

    2005-01-01

    , beta-cells showed marked sensitivity to apoptosis induced by SERCA blockers, as compared with fibroblasts. Cytokine-induced ER Ca(2+) depletion was paralleled by an NO-dependent induction of CHOP protein and activation of diverse components of the ER stress response, including activation of inositol......Cytokines and free radicals are mediators of beta-cell death in type 1 diabetes. Under in vitro conditions, interleukin-1beta (IL-1beta) + gamma-interferon (IFN-gamma) induce nitric oxide (NO) production and apoptosis in rodent and human pancreatic beta-cells. We have previously shown......, by microarray analysis of primary beta-cells, that IL-1beta + IFN-gamma decrease expression of the mRNA encoding for the sarcoendoplasmic reticulum pump Ca(2+) ATPase 2b (SERCA2b) while inducing expression of the endoplasmic reticulum stress-related and proapoptotic gene CHOP (C/EBP [CCAAT/enhancer binding...

  9. Atf6 plays protective and pathologic roles in fatty liver disease due to endoplasmic reticulum stress

    Science.gov (United States)

    Cinaroglu, Ayca; Gao, Chuan; Imrie, Dru; Sadler, Kirsten C.

    2011-01-01

    Many etiologies of fatty liver disease (FLD) are associated with hyper-activation of one of the three pathways that comprise the unfolded protein response (UPR), a harbinger of endoplasmic reticulum (ER) stress. The UPR is mediated by pathways initiated by PERK, IRE1a/XBP1and ATF6, and each of these pathways have been implicated as either protective or pathological in FLD. We use zebrafish with FLD and hepatic ER stress to explore the relationship between Atf6 and steatosis. Mutation of the foie gras (foigr) gene causes FLD and hepatic ER stress. Prolonged treatment of wild-type larvae with a dose of tunicamycin that causes chronic ER stress phenocopies foigr. In contrast, acute exposure to a high dose of tunicamycin robustly activates the UPR but is less effective at inducing steatosis. The Srebp transcription factors are not required for steatosis in any of these models. Instead, depleting larvae of active Atf6 either through mbtps1 mutation or atf6 morpholino injection protects against steatosis caused by chronic ER stress whereas it exacerbates steatosis caused by acute tunicamycin treatment. Conclusion ER stress causes FLD. Loss of Atf6 prevents steatosis caused by chronic ER stress but can also potentiate steatosis caused by acute ER stress. This demonstrates that Atf6 can play both protective and pathological roles in FLD. PMID:21538441

  10. Lyn kinase represses mucus hypersecretion by regulating IL-13-induced endoplasmic reticulum stress in asthma.

    Science.gov (United States)

    Wang, Xing; Yang, Xiaoqiong; Li, Yin; Wang, Xiaoyun; Zhang, Yun; Dai, Xi; Niu, Bin; Wu, Juan; Yuan, Xiefang; Xiong, Anjie; Liu, Zhigang; Zhong, Nanshan; Wu, Min; Li, Guoping

    2017-02-01

    In asthma, mucus hypersecretion is thought to be a prominent pathological feature associated with widespread mucus plugging. However, the current treatments for mucus hypersecretion are often ineffective or temporary. The potential therapeutic targets of mucus hypersecretion in asthma remain unknown. Here, we show that Lyn is a central effector of endoplasmic reticulum stress (ER stress) and mucous hypersecretion in asthma. In Lyn-transgenic mice (Lyn-TG) and wild-type (WT) C57BL/6J mice exposed to ovalbumin (OVA), Lyn overexpression attenuates mucus hypersecretion and ER stress. Interleukin 13 (IL-13) induced MUC5AC expression by enhancing ER stress in vitro. Lyn serves as a negative regulator of IL-13-induced ER stress and MUC5AC expression. We further find that an inhibitor of ER stress, which is likely involved in the PI3K p85α/Akt pathway and NFκB activity, blocked MUC5AC expression in Lyn-knockdown cells. Furthermore, PI3K/Akt signaling is required for IL-13-induced ER stress and MUC5AC expression in airway epithelial cells. The ER stress regulation of MUC5AC expression depends on NFκB in Lyn-knockdown airway epithelial cells. Our studies indicate not only a concept of mucus hypersecretion in asthma that involves Lyn kinase but also an important therapeutic candidate for asthma.

  11. Effect of amiloride on endoplasmic reticulum stress response in the injured spinal cord of rats.

    Science.gov (United States)

    Kuroiwa, Masahiro; Watanabe, Masahiko; Katoh, Hiroyuki; Suyama, Kaori; Matsuyama, Daisuke; Imai, Takeshi; Mochida, Joji

    2014-10-01

    After traumatic spinal cord injury (SCI), endoplasmic reticulum (ER) stress exacerbates secondary injury, leading to expansion of demyelination and reduced remyelination due to oligodendrocyte precursor cell (OPC) apoptosis. Although recent studies have revealed that amiloride controls ER stress and leads to improvement in several neurological disorders including SCI, its mechanism is not completely understood. Here, we used a rat SCI model to assess the effects of amiloride on functional recovery, secondary damage expansion, ER stress-induced cell death and OPC survival. Hindlimb function in rats with spinal cord contusion significantly improved after amiloride administration. Amiloride significantly decreased the expression of the pro-apoptotic transcription factor CHOP in the injured spinal cord and significantly increased the expression of the ER chaperone GRP78, which protects cells against ER stress. In addition, amiloride treatment led to a significant decrease in ER stress-induced apoptosis and a significant increase of NG2-positive OPCs in the injured spinal cord. Furthermore, in vitro experiments performed to investigate the direct effect of amiloride on OPCs revealed that amiloride reduced CHOP expression in OPCs cultured under ER stress. These results suggest that amiloride controls ER stress in SCI and inhibits cellular apoptosis, contributing to OPC survival. The present study suggests that amiloride may be an effective treatment to reduce ER stress-induced cell death in the acute phase of SCI.

  12. Lyn kinase represses mucus hypersecretion by regulating IL-13-induced endoplasmic reticulum stress in asthma

    Directory of Open Access Journals (Sweden)

    Xing Wang

    2017-02-01

    Full Text Available In asthma, mucus hypersecretion is thought to be a prominent pathological feature associated with widespread mucus plugging. However, the current treatments for mucus hypersecretion are often ineffective or temporary. The potential therapeutic targets of mucus hypersecretion in asthma remain unknown. Here, we show that Lyn is a central effector of endoplasmic reticulum stress (ER stress and mucous hypersecretion in asthma. In Lyn-transgenic mice (Lyn-TG and wild-type (WT C57BL/6J mice exposed to ovalbumin (OVA, Lyn overexpression attenuates mucus hypersecretion and ER stress. Interleukin 13 (IL-13 induced MUC5AC expression by enhancing ER stress in vitro. Lyn serves as a negative regulator of IL-13-induced ER stress and MUC5AC expression. We further find that an inhibitor of ER stress, which is likely involved in the PI3K p85α/Akt pathway and NFκB activity, blocked MUC5AC expression in Lyn-knockdown cells. Furthermore, PI3K/Akt signaling is required for IL-13-induced ER stress and MUC5AC expression in airway epithelial cells. The ER stress regulation of MUC5AC expression depends on NFκB in Lyn-knockdown airway epithelial cells. Our studies indicate not only a concept of mucus hypersecretion in asthma that involves Lyn kinase but also an important therapeutic candidate for asthma.

  13. Endoplasmic reticulum stress regulates inflammation and insulin resistance in skeletal muscle from pregnant women.

    Science.gov (United States)

    Liong, Stella; Lappas, Martha

    2016-04-15

    Sterile inflammation and infection are key mediators of inflammation and peripheral insulin resistance associated with gestational diabetes mellitus (GDM). Studies have shown endoplasmic reticulum (ER) stress to induce inflammation and insulin resistance associated with obesity and type 2 diabetes, however is paucity of studies investigating the effects of ER stress in skeletal muscle on inflammation and insulin resistance associated with GDM. ER stress proteins IRE1α, GRP78 and XBP-1s were upregulated in skeletal muscle of obese pregnant women, whereas IRE1α was increased in GDM women. Suppression of ER stress, using ER stress inhibitor tauroursodeoxycholic acid (TUDCA) or siRNA knockdown of IRE1α and GRP78, significantly downregulated LPS-, poly(I:C)- or IL-1β-induced production of IL-6, IL-8, IL-1β and MCP-1. Furthermore, LPS-, poly(I:C)- or TNF-α-induced insulin resistance was improved following suppression of ER stress, by increasing insulin-stimulated phosphorylation of IR-β, IRS-1, GLUT-4 expression and glucose uptake. In summary, our inducible obesity and GDM-like models suggests that the development of GDM may be involved in activating ER stress-induced inflammation and insulin resistance in human skeletal muscle.

  14. Hypercholesterolemia aggravates myocardial ischemia reperfusion injury via activating endoplasmic reticulum stress-mediated apoptosis.

    Science.gov (United States)

    Wu, Nan; Zhang, Xiaowen; Jia, Pengyu; Jia, Dalin

    2015-12-01

    The effect of hypercholesterolemia on myocardial ischemia reperfusion injury (MIRI) is in controversy and the underlying mechanism is still not well understood. In the present study, we firstly detected the effects of hypercholesterolemia on MIRI and the role of endoplasmic reticulum (ER) stress-mediated apoptosis pathway in this process. The infarct size was determined by TTC staining, and apoptosis was measured by the TUNEL method. The marker proteins of ER stress response and ER stress-mediated apoptosis pathway were detected by Western blot. The results showed that high cholesterol diet-induced hypercholesterolemia significantly increased the myocardial infarct size, the release of myocardium enzyme and the ratio of apoptosis, but did not affect the recovery of cardiac function. Moreover, hypercholesterolemia also remarkably up-regulated the expressions of ER stress markers (glucose-regulated protein 78 and calreticulin) and critical molecules in ER stress-mediated apoptosis pathway (CHOP, caspase 12, phospho-JNK). In conclusion, our study demonstrated that hypercholesterolemia enhanced myocardial vulnerability/sensitivity to ischemia reperfusion injury involved in aggravation the ER stress and activation of ER stress-mediated apoptosis pathway and it gave us a new insight into the underlying mechanisms associated with hypercholesterolemia-induced exaggerated MIRI and also provided a novel target for preventing MIRI in the presence of hypercholesterolemia. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Endoplasmic reticulum stress promotes amyloid-beta peptides production in RGC-5 cells.

    Science.gov (United States)

    Liu, Bingqian; Zhu, Yingting; Zhou, Jiayi; Wei, Yantao; Long, Chongde; Chen, Mengfei; Ling, Yunlan; Ge, Jian; Zhuo, Yehong

    2014-11-01

    Endoplasmic reticulum (ER) stress has been implicated in various neurodegenerative diseases, including Alzheimer's disease. We have previously observed amyloid production in the retina of the Tg2576 transgenic mouse model of Alzheimer's disease. In this study, we used tunicamycin-induced ER stress in RGC-5 cells, a cell line identical to the photoreceptor cell line 661W, to investigate the effect of ER stress on production of amyloid-beta (Abeta) peptides. We found that the mRNA level of amyloid-beta precursor protein (APP) remained stable, while the protein level of amyloid-beta precursor protein (APP) was decreased, the amyloid-beta precursor protein cleaving enzymes beta-site APP-cleaving enzyme 1 and presenilin 1 were upregulated, Abeta1-40 and Abeta1-42 production were increased, and reactive oxygen species production and apoptosis markers were elevated following induction of ER stress. The protein level of Abeta degradation enzymes, neprilysin, endothelin-converting enzyme 1, and endothelin-converting enzyme 2 remained unchanged during the prolonged ER stress, showing that the generation of Abeta did not result from reduction of proteolysis by these enzymes. Inclusion of group II caspase inhibitor, Z-DEVD-FMK, increased the ER stress mediated Abeta production, suggesting that they are generated by a caspase-independent mechanism. Our findings provided evidence of a role of ER stress in Abeta peptide overproduction and apoptotic pathway activation in RGC-5 cells.

  16. Endoplasmic reticulum stress suppresses lipin-1 expression in 3T3-L1 adipocytes

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Nobuhiko, E-mail: ntkhs@hoku-iryo-u.ac.jp [Department of Internal Medicine, School of Dentistry, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan); Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1-1-1, Midorigaoka-Higashi, Asahikawa, Hokkaido 078-8510 (Japan); Yoshizaki, Takayuki [Innovation Center, Kagoshima University, 1-21-40, Korimoto, Kagoshima 890-0065 (Japan); Hiranaka, Natsumi; Suzuki, Takeshi [Department of Internal Medicine, School of Dentistry, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan); Yui, Tomoo; Akanuma, Masayoshi [Department of Fixed Prosthodontics and Oral Implantology, School of Dentistry, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan); Kanazawa, Kaoru [Department of Dental Anesthesiology, School of Dentistry, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan); Yoshida, Mika; Naito, Sumiyoshi [Department of Clinical Laboratory, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan); Fujiya, Mikihiro; Kohgo, Yutaka [Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1-1-1, Midorigaoka-Higashi, Asahikawa, Hokkaido 078-8510 (Japan); Ieko, Masahiro [Department of Internal Medicine, School of Dentistry, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan)

    2013-02-01

    Highlights: ► Lipin-1 involves lipid metabolism, adipocyte differentiation, and inflammation. ► Adipose lipin-1 expression is reduced in obesity. ► ER stress suppresses lipin-1 expression in 3T3-L1 adipocytes. ► Activation of PPAR-γ recovers ER stress-induced lipin-1 reduction. -- Abstract: Lipin-1 plays crucial roles in the regulation of lipid metabolism and cell differentiation in adipocytes. In obesity, adipose lipin-1 mRNA expression is decreased and positively correlated with systemic insulin sensitivity. Amelioration of the lipin-1 depletion might be improved dysmetabolism. Although some cytokines such as TNF-α and interleukin-1β reduces adipose lipin-1 expression, the mechanism of decreased adipose lipin-1 expression in obesity remains unclear. Recently, endoplasmic reticulum (ER) stress is implicated in the pathogenesis of obesity. Here we investigated the role of ER stress on the lipin-1 expression in 3T3-L1 adipocytes. We demonstrated that lipin-1 expression was suppressed by the treatment with ER stress inducers (tunicamycin and thapsigargin) at transcriptional level. We also showed that constitutive lipin-1 expression could be maintained by peroxisome proliferator-activated receptor-γ in 3T3-L1 adipocytes. Activation of peroxisome proliferator-activated receptor-γ recovered the ER stress-induced lipin-1 suppression. These results suggested that ER stress might be involved in the pathogenesis of obesity through lipin-1 depletion.

  17. Protective Effect of Gomisin N against Endoplasmic Reticulum Stress-Induced Hepatic Steatosis.

    Science.gov (United States)

    Jang, Min-Kyung; Yun, Ye-Rang; Kim, Seon Hoo; Kim, Ji Ha; Jung, Myeong Ho

    2016-05-01

    Gomisin N is a physiological substance derived from Schisandra chinensis. In the present study, the in vitro and in vivo effects of gomisin N on endoplasmic reticulum (ER) stress and hepatic steatosis were investigated. We quantified the expression of markers of ER stress, including glucose regulated protein 78 (GRP78), CCAAT/enhancer binding protein (C/EBP) homolog protein (CHOP), and X-box-binding protein-1 (XBP-1), and triglyceride (TG) accumulation, in HepG2 cells treated with tunicamycin or palmitate. Tunicamycin treatment in HepG2 cells induced expression of markers of ER stress and increased TG levels; Gomisin N reversed these effects, reducing the expression of markers of ER stress and TG levels. Similar effects were seen following palmitate pretreatment of HepG2 cells. The inhibitory effects of gomisin N were further confirmed in mice injected with tunicamycin. Gomisin N reduced expression of markers of ER stress and decreased TG levels in mouse liver after tunicamycin injection. Furthermore, gomisin N decreased expression of inflammatory and lipogenic genes in palmitate-incubated HepG2 cells. These results suggest that gomisin N inhibits ER stress and ameliorates hepatic steatosis induced by ER stress.

  18. KLF15 is a molecular link between endoplasmic reticulum stress and insulin resistance.

    Directory of Open Access Journals (Sweden)

    Dae Young Jung

    Full Text Available Obesity places major demands on the protein folding capacity of the endoplasmic reticulum (ER, resulting in ER stress, a condition that promotes hepatic insulin resistance and steatosis. Here we identify the transcription factor, Kruppel-like factor 15 (KLF15, as an essential mediator of ER stress-induced insulin resistance in the liver. Mice with a targeted deletion of KLF15 exhibit increased hepatic ER stress, inflammation, and JNK activation compared to WT mice; however, KLF15 (-/- mice are protected against hepatic insulin resistance and fatty liver under high-fat feeding conditions and in response to pharmacological induction of ER stress. The mammalian target of rapamycin complex 1 (mTORC1, a key regulator of cellular energy homeostasis, has been shown to cooperate with ER stress signaling pathways to promote hepatic insulin resistance and lipid accumulation. We find that the uncoupling of ER stress and insulin resistance in KLF15 (-/- liver is associated with the maintenance of a low energy state characterized by decreased mTORC1 activity, increased AMPK phosphorylation and PGC-1α expression and activation of autophagy, an intracellular degradation process that enhances hepatic insulin sensitivity. Furthermore, in primary hepatocytes, KLF15 deficiency markedly inhibits activation of mTORC1 by amino acids and insulin, suggesting a mechanism by which KLF15 controls mTORC1-mediated insulin resistance. This study establishes KLF15 as an important molecular link between ER stress and insulin action.

  19. Surviving endoplasmic reticulum stress is coupled to altered chondrocyte differentiation and function.

    Directory of Open Access Journals (Sweden)

    Kwok Yeung Tsang

    2007-03-01

    Full Text Available In protein folding and secretion disorders, activation of endoplasmic reticulum (ER stress signaling (ERSS protects cells, alleviating stress that would otherwise trigger apoptosis. Whether the stress-surviving cells resume normal function is not known. We studied the in vivo impact of ER stress in terminally differentiating hypertrophic chondrocytes (HCs during endochondral bone formation. In transgenic mice expressing mutant collagen X as a consequence of a 13-base pair deletion in Col10a1 (13del, misfolded alpha1(X chains accumulate in HCs and elicit ERSS. Histological and gene expression analyses showed that these chondrocytes survived ER stress, but terminal differentiation is interrupted, and endochondral bone formation is delayed, producing a chondrodysplasia phenotype. This altered differentiation involves cell-cycle re-entry, the re-expression of genes characteristic of a prehypertrophic-like state, and is cell-autonomous. Concomitantly, expression of Col10a1 and 13del mRNAs are reduced, and ER stress is alleviated. ERSS, abnormal chondrocyte differentiation, and altered growth plate architecture also occur in mice expressing mutant collagen II and aggrecan. Alteration of the differentiation program in chondrocytes expressing unfolded or misfolded proteins may be part of an adaptive response that facilitates survival and recovery from the ensuing ER stress. However, the altered differentiation disrupts the highly coordinated events of endochondral ossification culminating in chondrodysplasia.

  20. Relevance of Endoplasmic Reticulum Stress Cell Signaling in Liver Cold Ischemia Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Emma Folch-Puy

    2016-05-01

    Full Text Available The endoplasmic reticulum (ER is involved in calcium homeostasis, protein folding and lipid biosynthesis. Perturbations in its normal functions lead to a condition called endoplasmic reticulum stress (ERS. This can be triggered by many physiopathological conditions such as alcoholic steatohepatitis, insulin resistance or ischemia-reperfusion injury. The cell reacts to ERS by initiating a defensive process known as the unfolded protein response (UPR, which comprises cellular mechanisms for adaptation and the safeguarding of cell survival or, in cases of excessively severe stress, for the initiation of the cell death program. Recent experimental data suggest the involvement of ERS in ischemia/reperfusion injury (IRI of the liver graft, which has been considered as one of major problems influencing outcome after liver transplantation. The purpose of this review is to summarize updated data on the molecular mechanisms of ERS/UPR and the consequences of this pathology, focusing specifically on solid organ preservation and liver transplantation models. We will also discuss the potential role of ERS, beyond the simple adaptive response and the regulation of cell death, in the modification of cell functional properties and phenotypic changes.

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

    Science.gov (United States)

    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.

  2. The metabolomic signature of Leber's hereditary optic neuropathy reveals endoplasmic reticulum stress.

    Science.gov (United States)

    Chao de la Barca, Juan Manuel; Simard, Gilles; Amati-Bonneau, Patrizia; Safiedeen, Zainab; Prunier-Mirebeau, Delphine; Chupin, Stéphanie; Gadras, Cédric; Tessier, Lydie; Gueguen, Naïg; Chevrollier, Arnaud; Desquiret-Dumas, Valérie; Ferré, Marc; Bris, Céline; Kouassi Nzoughet, Judith; Bocca, Cinzia; Leruez, Stéphanie; Verny, Christophe; Miléa, Dan; Bonneau, Dominique; Lenaers, Guy; Martinez, M Carmen; Procaccio, Vincent; Reynier, Pascal

    2016-09-15

    the greater expression of C/EBP homologous protein and the increased XBP1 splicing, in fibroblasts from affected patients, all these changes being reversed by the endoplasmic reticulum stress inhibitor, TUDCA (tauroursodeoxycholic acid). Thus, our metabolomic analysis reveals a pharmacologically-reversible endoplasmic reticulum stress in complex I-related Leber's hereditary optic neuropathy fibroblasts, a finding that may open up new therapeutic perspectives for the treatment of Leber's hereditary optic neuropathy with endoplasmic reticulum-targeting drugs.

  3. Novel targets for endoplasmic reticulum stress-induced apoptosis in B-CLL.

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    Rosati, Emanuela; Sabatini, Rita; Rampino, Giuliana; De Falco, Filomena; Di Ianni, Mauro; Falzetti, Franca; Fettucciari, Katia; Bartoli, Andrea; Screpanti, Isabella; Marconi, Pierfrancesco

    2010-10-14

    A better understanding of apoptotic signaling in B-chronic lymphocytic leukemia (B-CLL) cells may help to define new therapeutic strategies. This study investigated endoplasmic reticulum (ER) stress signaling in spontaneous apoptosis of B-CLL cells and whether manipulating ER stress increases their apoptosis. Results show that a novel ER stress-triggered caspase cascade, initiated by caspase-4 and involving caspase-8 and -3, plays an important role in spontaneous B-CLL cell apoptosis. ER stress-induced apoptosis in B-CLL cells also involves CHOP/GADD153 up-regulation, increased JNK1/2 phosphorylation, and caspase-8-mediated cleavage of Bap31 to Bap20, known to propagate apoptotic signals from ER to mitochondria. In ex vivo B-CLL cells, some apoptotic events associated with mitochondrial pathway also occur, including mitochondrial cytochrome c release and caspase-9 processing. However, pharmacologic inhibition studies show that caspase-9 plays a minor role in B-CLL cell apoptosis. ER stress also triggers survival signals in B-CLL cells by increasing BiP/GRP78 expression. Manipulating ER signaling by siRNA down-regulation of BiP/GRP78 or treating B-CLL cells with 2 well-known ER stress-inducers, tunicamycin and thapsigargin, increases their apoptosis. Overall, our findings show that ER triggers an essential pathway for B-CLL cell apoptosis and suggest that genetic and pharmacologic manipulation of ER signaling could represent an important therapeutic strategy.

  4. ATF4- and CHOP-Dependent Induction of FGF21 through Endoplasmic Reticulum Stress

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    Xiao-shan Wan

    2014-01-01

    Full Text Available Fibroblast growth factor 21 (FGF21 is an important endogenous regulator involved in the regulation of glucose and lipid metabolism. FGF21 expression is strongly induced in animal and human subjects with metabolic diseases, but little is known about the molecular mechanism. Endoplasmic reticulum (ER stress plays an essential role in metabolic homeostasis and is observed in numerous pathological processes, including type 2 diabetes, overweight, nonalcoholic fatty liver disease (NAFLD. In this study, we investigate the correlation between the expression of FGF21 and ER stress. We demonstrated that TG-induced ER stress directly regulated the expression and secretion of FGF21 in a dose- and time-dependent manner. FGF21 is the target gene for activating transcription factor 4 (ATF4 and CCAAT enhancer binding protein homologous protein (CHOP. Suppression of CHOP impaired the transcriptional activation of FGF21 by TG-induced ER stress in CHOP−/− mouse primary hepatocytes (MPH, and overexpression of ATF4 and CHOP resulted in FGF21 promoter activation to initiate the transcriptional programme. In mRNA stability assay, we indicated that ER stress increased the half-life of mRNA of FGF21 significantly. In conclusion, FGF21 expression is regulated by ER stress via ATF- and CHOP-dependent transcriptional mechanism and posttranscriptional mechanism, respectively.

  5. Expression of Endoplasmic Reticulum Stress-Related Factors in the Retinas of Diabetic Rats

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    Shu Yan

    2012-01-01

    Full Text Available Recent reports show that ER stress plays an important role in diabetic retinopathy (DR, but ER stress is a complicated process involving a network of signaling pathways and hundreds of factors, What factors involved in DR are not yet understood. We selected 89 ER stress factors from more than 200, A rat diabetes model was established by intraperitoneal injection of streptozotocin (STZ. The expression of 89 ER stress-related factors was found in the retinas of diabetic rats, at both 1- and 3-months after development of diabetes, by quantitative real-time polymerase chain reaction arrays. There were significant changes in expression levels of 13 and 12 ER stress-related factors in the diabetic rat retinas in the first and third month after the development of diabetes, Based on the array results, homocysteine- inducible, endoplasmic reticulum stress-inducible, ubiquitin-like domain member 1(HERP, and synoviolin(HRD1 were studied further by immunofluorescence and Western blot. Immunofluorescence and Western blot analyses showed that the expression of HERP was reduced in the retinas of diabetic rats in first and third month. The expression of Hrd1 did not change significantly in the retinas of diabetic rats in the first month but was reduced in the third month.

  6. Prodigiosin activates endoplasmic reticulum stress cell death pathway in human breast carcinoma cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Mu-Yun [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Shen, Yuh-Chiang [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); National Research Institute of Chinese Medicine, Taipei, Taiwan (China); Lu, Chien-Hsing [Department of Obstetrics and Gynecology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Department of Obstetrics and Gynecology, National Yang-Ming University School of Medicine, Taipei, Taiwan (China); Yang, Shu-Yi [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Ho, Tsing-Fen [Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan (China); Peng, Yu-Ta [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Chang, Chia-Che, E-mail: chia_che@dragon.nchu.edu.tw [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan (China); Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan (China)

    2012-12-15

    Prodigiosin is a bacterial tripyrrole pigment with potent cytotoxicity against diverse human cancer cell lines. Endoplasmic reticulum (ER) stress is initiated by accumulation of unfolded or misfolded proteins in the ER lumen and may induce cell death when irremediable. In this study, the role of ER stress in prodigiosin-induced cytotoxicity was elucidated for the first time. Comparable to the ER stress inducer thapsigargin, prodigiosin up-regulated signature ER stress markers GRP78 and CHOP in addition to activating the IRE1, PERK and ATF6 branches of the unfolded protein response (UPR) in multiple human breast carcinoma cell lines, confirming prodigiosin as an ER stress inducer. Prodigiosin transcriptionally up-regulated CHOP, as evidenced by its promoting effect on the CHOP promoter activity. Of note, knockdown of CHOP effectively lowered prodigiosin's capacity to evoke PARP cleavage, reduce cell viability and suppress colony formation, highlighting an essential role of CHOP in prodigiosin-induced cytotoxic ER stress response. In addition, prodigiosin down-regulated BCL2 in a CHOP-dependent manner. Importantly, restoration of BCL2 expression blocked prodigiosin-induced PARP cleavage and greatly enhanced the survival of prodigiosin-treated cells, suggesting that CHOP-dependent BCL2 suppression mediates prodigiosin-elicited cell death. Moreover, pharmacological inhibition of JNK by SP600125 or dominant-negative blockade of PERK-mediated eIF2α phosphorylation impaired prodigiosin-induced CHOP up-regulation and PARP cleavage. Collectively, these results identified ER stress-mediated cell death as a mode-of-action of prodigiosin's tumoricidal effect. Mechanistically, prodigiosin engages the IRE1–JNK and PERK–eIF2α branches of the UPR signaling to up-regulate CHOP, which in turn mediates BCL2 suppression to induce cell death. Highlights: ► Prodigiosin is a bacterial tripyrrole pigment with potent anticancer effect. ► Prodigiosin is herein identified

  7. Kaempferol Inhibits Endoplasmic Reticulum Stress-Associated Mucus Hypersecretion in Airway Epithelial Cells And Ovalbumin-Sensitized Mice.

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    Park, Sin-Hye; Gong, Ju-Hyun; Choi, Yean-Jung; Kang, Min-Kyung; Kim, Yun-Ho; Kang, Young-Hee

    2015-01-01

    Mucus hypersecretion is an important pathological feature of chronic airway diseases, such as asthma and pulmonary diseases. MUC5AC is a major component of the mucus matrix forming family of mucins in the airways. The initiation of endoplasmic reticulum (ER)-mediated stress responses contributes to the pathogenesis of airway diseases. The present study investigated that ER stress was responsible for airway mucus production and this effect was blocked by the flavonoid kaempferol. Oral administration of ≥10 mg/kg kaempferol suppressed mucus secretion and goblet cell hyperplasia observed in the bronchial airway and lung of BALB/c mice sensitized with ovalbumin (OVA). TGF-β and tunicamycin promoted MUC5AC induction after 72 h in human bronchial airway epithelial BEAS-2B cells, which was dampened by 20 μM kaempferol. Kaempferol inhibited tunicamycin-induced ER stress of airway epithelial cells through disturbing the activation of the ER transmembrane sensor ATF6 and IRE1α. Additionally, this compound demoted the induction of ER chaperones such as GRP78 and HSP70 and the splicing of XBP-1 mRNA by tunicamycin. The in vivo study further revealed that kaempferol attenuated the induction of XBP-1 and IRE1α in epithelial tissues of OVA-challenged mice. TGF-β and tunicamycin induced TRAF2 with JNK activation and such induction was deterred by kaempferol. The inhibition of JNK activation encumbered the XBP-1 mRNA splicing and MUC5AC induction by tunicamycin and TGF-β. These results demonstrate that kaempferol alleviated asthmatic mucus hypersecretion through blocking bronchial epithelial ER stress via the inhibition of IRE1α-TRAF2-JNK activation. Therefore, kaempferol may be a potential therapeutic agent targeting mucus hypersecretion-associated pulmonary diseases.

  8. Ammonia exposure induces oxidative stress, endoplasmic reticulum stress and apoptosis in hepatopancreas of pacific white shrimp (Litopenaeus vannamei).

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    Liang, Zhongxiu; Liu, Rui; Zhao, Depeng; Wang, Lingling; Sun, Mingzhe; Wang, Mengqiang; Song, Linsheng

    2016-07-01

    Ammonia is one of major environmental pollutants in the aquatic system that poses a great threat to the survival of shrimp. In the present study, the mRNA expression of endoplasmic reticulum (ER) stress marker and unfolded protein response (UPR) related genes, as well as the change of redox enzyme and apoptosis were investigated in hepatopancreas of the pacific white shrimp, Litopenaeus vannamei after the exposure of 20 mg L(-1) total ammonia nitrogen (TAN). Compared with the control group, the superoxide dismutase (SOD) activity in hepatopancreas decreased significantly (p vannamei after exposure to ammonia by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. The results indicated that ammonia exposure could induce oxidative stress, which further caused ER stress and apoptosis in hepatopancreas of L. vannamei.

  9. Endoplasmic reticulum stress-induced apoptosis in the penumbra aggravates secondary damage in rats with traumatic brain injur y

    Institute of Scientific and Technical Information of China (English)

    Guo-zhu Sun; Fen-fei Gao; Zong-mao Zhao; Hai Sun; Wei Xu; Li-wei Wu; Yong-chang He

    2016-01-01

    Neuronal apoptosis is mediated by intrinsic and extrinsic signaling pathways such as the membrane-mediated, mitochondrial, and endo-plasmic reticulum stress pathways. Few studies have examined the endoplasmic reticulum-mediated apoptosis pathway in the penumbra after traumatic brain injury, and it remains unclear whether endoplasmic reticulum stress can activate the caspase-12-dependent apoptotic pathway in the traumatic penumbra. Here, we established rat models of lfuid percussion-induced traumatic brain injury and found that protein expression of caspase-12, caspase-3 and the endoplasmic reticulum stress marker 78 kDa glucose-regulated protein increased in the traumatic penumbra 6 hours after injury and peaked at 24 hours. Furthermore, numbers of terminal deoxynucleotidyl transferase-mediat-ed dUTP nick end labeling-positive cells in the traumatic penumbra also reached peak levels 24 hours after injury. These ifndings suggest that caspase-12-mediated endoplasmic reticulum-related apoptosis is activated in the traumatic penumbra, and may play an important role in the pathophysiology of secondary brain injury.

  10. The adaptive endoplasmic reticulum stress response to lipotoxicity in progressive human nonalcoholic fatty liver disease.

    Science.gov (United States)

    Lake, April D; Novak, Petr; Hardwick, Rhiannon N; Flores-Keown, Brieanna; Zhao, Fei; Klimecki, Walter T; Cherrington, Nathan J

    2014-01-01

    Nonalcoholic fatty liver disease (NAFLD) may progress from simple steatosis to severe, nonalcoholic steatohepatitis (NASH) in 7%-14% of the U.S. population through a second "hit" in the form of increased oxidative stress and inflammation. Endoplasmic reticulum (ER) stress signaling and the unfolded protein response (UPR) are triggered when high levels of lipids and misfolded proteins alter ER homeostasis creating a lipotoxic environment within NAFLD livers. The objective of this study was to determine the coordinate regulation of ER stress-associated genes in the progressive stages of human NAFLD. Human liver samples categorized as normal, steatosis, NASH (Fatty), and NASH (Not Fatty) were analyzed by individual Affymetrix GeneChip Human 1.0 ST microarrays, immunoblots, and immunohistochemistry. A gene set enrichment analysis was performed on autophagy, apoptosis, lipogenesis, and ER stress/UPR gene categories. An enrichment of downregulated genes in the ER stress-associated lipogenesis and ER stress/UPR gene categories was observed in NASH. Conversely, an enrichment of upregulated ER stress-associated genes for autophagy and apoptosis gene categories was observed in NASH. Protein expression of the adaptive liver response protein STC2 and the transcription factor X-box binding protein 1 spliced (XBP-1s) were significantly elevated among NASH samples, whereas other downstream ER stress proteins including CHOP, ATF4, and phosphorylated JNK and eIF2α were not significantly changed in disease progression. Increased nuclear accumulation of total XBP-1 protein was observed in steatosis and NASH livers. The findings reveal the presence of a coordinated, adaptive transcriptional response to hepatic ER stress in human NAFLD.

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

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    Lee, Yea-Jin [Department of Biotechnology, Hoseo University, Baebang, Asan, Chungnam, 336-795 (Korea, Republic of); Kim, Sung-Jo, E-mail: sungjo@hoseo.edu [Department of Biotechnology, Hoseo University, Baebang, Asan, Chungnam, 336-795 (Korea, Republic of); Heo, Tae-Hwe, E-mail: thhur92@catholic.ac.kr [College of Pharmacy, The Catholic University of Korea, Bucheon 420-743 (Korea, Republic of)

    2011-09-23

    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 in 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.

  12. The anaphase-promoting complex or cyclosome supports cell survival in response to endoplasmic reticulum stress.

    Directory of Open Access Journals (Sweden)

    Meifan Chen

    Full Text Available The anaphase-promoting complex or cyclosome (APC/C is a multi-subunit ubiquitin ligase that regulates exit from mitosis and G1 phase of the cell cycle. Although the regulation and function of APC/C(Cdh1 in the unperturbed cell cycle is well studied, little is known of its role in non-genotoxic stress responses. Here, we demonstrate the role of APC/C(Cdh1 (APC/C activated by Cdh1 protein in cellular protection from endoplasmic reticulum (ER stress. Activation of APC/C(Cdh1 under ER stress conditions is evidenced by Cdh1-dependent degradation of its substrates. Importantly, the activity of APC/C(Cdh1 maintains the ER stress checkpoint, as depletion of Cdh1 by RNAi impairs cell cycle arrest and accelerates cell death following ER stress. Our findings identify APC/C(Cdh1 as a regulator of cell cycle checkpoint and cell survival in response to proteotoxic insults.

  13. Cannabidiol protects oligodendrocyte progenitor cells from inflammation-induced apoptosis by attenuating endoplasmic reticulum stress.

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    Mecha, M; Torrao, A S; Mestre, L; Carrillo-Salinas, F J; Mechoulam, R; Guaza, C

    2012-06-28

    Cannabidiol (CBD) is the most abundant cannabinoid in Cannabis sativa that has no psychoactive properties. CBD has been approved to treat inflammation, pain and spasticity associated with multiple sclerosis (MS), of which demyelination and oligodendrocyte loss are hallmarks. Thus, we investigated the protective effects of CBD against the damage to oligodendrocyte progenitor cells (OPCs) mediated by the immune system. Doses of 1 μM CBD protect OPCs from oxidative stress by decreasing the production of reactive oxygen species. CBD also protects OPCs from apoptosis induced by LPS/IFNγ through the decrease of caspase 3 induction via mechanisms that do not involve CB1, CB2, TRPV1 or PPARγ receptors. Tunicamycin-induced OPC death was attenuated by CBD, suggesting a role of endoplasmic reticulum (ER) stress in the mode of action of CBD. This protection against ER stress-induced apoptosis was associated with reduced phosphorylation of eiF2α, one of the initiators of the ER stress pathway. Indeed, CBD diminished the phosphorylation of PKR and eiF2α induced by LPS/IFNγ. The pro-survival effects of CBD in OPCs were accompanied by decreases in the expression of ER apoptotic effectors (CHOP, Bax and caspase 12), and increased expression of the anti-apoptotic Bcl-2. These findings suggest that attenuation of the ER stress pathway is involved in the 'oligoprotective' effects of CBD during inflammation.

  14. Naphthoquinone Derivative PPE8 Induces Endoplasmic Reticulum Stress in p53 Null H1299 Cells

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    Jin-Cherng Lien

    2015-01-01

    Full Text Available Endoplasmic reticulum (ER plays a key role in synthesizing secretory proteins and sensing signal function in eukaryotic cells. Responding to calcium disturbance, oxidation state change, or pharmacological agents, ER transmembrane protein, inositol-regulating enzyme 1 (IRE1, senses the stress and triggers downstream signals. Glucose-regulated protein 78 (GRP78 dissociates from IRE1 to assist protein folding and guard against cell death. In prolonged ER stress, IRE1 recruits and activates apoptosis signal-regulating kinase 1 (ASK1 as well as downstream JNK for cell death. Naphthoquinones are widespread natural phenolic compounds. Vitamin K3, a derivative of naphthoquinone, inhibits variant tumor cell growth via oxygen uptake and oxygen stress. We synthesized a novel naphthoquinone derivative PPE8 and evaluated capacity to induce ER stress in p53 null H1299 and p53 wild-type A549 cells. In H1299 cells, PPE8 induced ER enlargement, GRP78 expression, and transient IER1 activation. Activated IRE1 recruited ASK1 for downstream JNK phosphorylation. IRE1 knockdown by siRNA attenuated PPE8-induced JNK phosphorylation and cytotoxicity. Prolonged JNK phosphorylation may be involved in PPE8-induced cytotoxicity. Such results did not arise in A549 cells, but p53 knockdown by siRNA restored PPE8-induced GRP78 expression and JNK phosphorylation. We offer a novel compound to induce ER stress and cytotoxicity in p53-deficient cancer cells, presenting an opportunity for treatment.

  15. Oxidative Homeostasis Regulates the Response to Reductive Endoplasmic Reticulum Stress through Translation Control

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    Shuvadeep Maity

    2016-07-01

    Full Text Available Reductive stress leads to the loss of disulfide bond formation and induces the unfolded protein response of the endoplasmic reticulum (UPRER, necessary to regain proteostasis in the compartment. Here we show that peroxide accumulation during reductive stress attenuates UPRER amplitude by altering translation without any discernible effect on transcription. Through a comprehensive genetic screen in Saccharomyces cerevisiae, we identify modulators of reductive stress-induced UPRER and demonstrate that oxidative quality control (OQC genes modulate this cellular response in the presence of chronic but not acute reductive stress. Using a combination of microarray and relative quantitative proteomics, we uncover a non-canonical translation attenuation mechanism that acts in a bipartite manner to selectively downregulate highly expressed proteins, decoupling the cell’s transcriptional and translational response during reductive ER stress. Finally, we demonstrate that PERK, a canonical translation attenuator in higher eukaryotes, helps in bypassing a ROS-dependent, non-canonical mode of translation attenuation.

  16. Fenofibrate treatment attenuated chronic endoplasmic reticulum stress in the liver of nonalcoholic fatty liver disease mice.

    Science.gov (United States)

    Zhang, Nan; Lu, Yunxia; Shen, Xinru; Bao, Yingying; Cheng, Jingjing; Chen, Li; Li, Bao; Zhang, Qiu

    2015-01-01

    Fenofibrate is widely used in clinical practice, but its influence on chronic endoplasmic reticulum (ER) stress induced by feeding a high-calorie and high-cholesterol diet (HCD) has still not been studied. We thus investigated its effects on the liver of the nonalcoholic fatty liver disease (NAFLD) mouse model. Male C57BL/6 mice fed an HCD for 3 months were treated with fenofibrate (HCD + FF, 40 mg/kg, once daily) via gavage for 4 weeks. Insulin sensitivity, serum lipid and inflammatory cytokines were measured. Liver tissues were procured for histological examination as well as analysis of hepatic triglyceride levels, distribution of inflammatory cytokines and genes involved in ER stress. Our results showed that chronic feeding of an HCD successfully induced an NAFLD model accompanied by inflammatory activation, apoptosis and severe ER stress in the liver. Fenofibrate administration significantly improved symptoms of NAFLD and decreased apoptosis, expression of inflammatory cytokines and genes involved in ER stress, such as inositol-requiring enzyme 1α (IRE1α), X-box binding protein 1 (XBP1) and JNK phosphorylation. Thus, our study suggests that fenofibrate protected against inflammatory injury and apoptosis, maybe alleviating ER stress through the IRE1α-XBP1-JNK pathway in the liver of NAFLD mice. © 2015 S. Karger AG, Basel

  17. Endoplasmic reticulum stress inhibition attenuates hypertensive chronic kidney disease through reduction in proteinuria

    Science.gov (United States)

    Mohammed-Ali, Zahraa; Lu, Chao; Marway, Mandeep K.; Carlisle, Rachel E.; Ask, Kjetil; Lukic, Dusan; Krepinsky, Joan C.; Dickhout, Jeffrey G.

    2017-01-01

    Endoplasmic reticulum (ER) stress is implicated in chronic kidney disease (CKD) development in patients and in animal models. Here we show that ER stress inhibition through 4-phenylbutyric acid (4-PBA) administration decreases blood pressure, albuminuria, and tubular casts in an angiotensin II/deoxycorticosterone acetate/salt murine model of CKD. Lower albuminuria in 4-PBA-treated mice was associated with higher levels of cubilin protein in renal tissue membrane fractions. 4-PBA decreased renal interstitial fibrosis, renal CD3+ T-cell and macrophage infiltration, mRNA expression of TGFβ1, Wnt signaling molecules, and ER stress-induced pro-inflammatory genes. CHOP deficient mice that underwent this model of CKD developed hypertension comparable to wild type mice, but had less albuminuria and tubular casts. CHOP deficiency resulted in higher nephrin levels and decreased glomerulosclerosis compared to wild type mice; this effect was accompanied by lower macrophage infiltration and fibrosis. Our findings portray ER stress inhibition as a means to alleviate hypertensive CKD by preserving glomerular barrier integrity and tubular function. These results demonstrate ER stress modulation as a novel target for preserving renal function in hypertensive CKD. PMID:28148966

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

    Science.gov (United States)

    Teng, Ru-Jeng; Jing, Xigang; Michalkiewicz, Teresa; Afolayan, Adeleye J; Wu, Tzong-Jin; Konduri, Girija G

    2017-05-01

    Rodent pups exposed to hyperoxia develop lung changes similar to bronchopulmonary dysplasia (BPD) in extremely premature infants. Oxidative stress from hyperoxia can injure developing lungs through endoplasmic reticulum (ER) stress. Early caffeine treatment decreases the rate of BPD, but the mechanisms remain unclear. We hypothesized that caffeine attenuates hyperoxia-induced lung injury through its chemical chaperone property. Sprague-Dawley rat pups were raised either in 90 (hyperoxia) or 21% (normoxia) oxygen from postnatal day 1 (P1) to postnatal day 10 (P10) and then recovered in 21% oxygen until P21. Caffeine (20 mg/kg) or normal saline (control) was administered intraperitoneally daily starting from P2. Lungs were inflation-fixed for histology or snap-frozen for immunoblots. Blood caffeine levels were measured in treated pups at euthanasia and were found to be 18.4 ± 4.9 μg/ml. Hyperoxia impaired alveolar formation and increased ER stress markers and downstream effectors; caffeine treatment attenuated these changes at P10. Caffeine also attenuated the hyperoxia-induced activation of cyclooxygenase-2 and markers of apoptosis. In conclusion, hyperoxia-induced alveolar growth impairment is mediated, in part, by ER stress. Early caffeine treatment protects developing lungs from hyperoxia-induced injury by attenuating ER stress. Copyright © 2017 the American Physiological Society.

  19. Involvement of Endoplasmic Reticulum Stress in Capsaicin-Induced Apoptosis of Human Pancreatic Cancer Cells

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    Shengzhang Lin

    2013-01-01

    Full Text Available Capsaicin, main pungent ingredient of hot chilli peppers, has been shown to have anticarcinogenic effect on various cancer cells through multiple mechanisms. In this study, we investigated the apoptotic effect of capsaicin on human pancreatic cancer cells in both in vitro and in vivo systems, as well as the possible mechanisms involved. In vitro, treatment of both the pancreatic cancer cells (PANC-1 and SW1990 with capsaicin resulted in cells growth inhibition, G0/G1 phase arrest, and apoptosis in a dose-dependent manner. Knockdown of growth arrest- and DNA damage-inducible gene 153 (GADD153, a marker of the endoplasmic-reticulum-stress- (ERS- mediated apoptosis pathway, by specific siRNA attenuated capsaicin-induced apoptosis both in PANC-1 and SW1990 cells. Moreover, in vivo studies capsaicin effectively inhibited the growth and metabolism of pancreatic cancer and prolonged the survival time of pancreatic cancer xenograft tumor-induced mice. Furthermore, capsaicin increased the expression of some key ERS markers, including glucose-regulated protein 78 (GRP78, phosphoprotein kinase-like endoplasmic reticulum kinase (phosphoPERK, and phosphoeukaryotic initiation factor-2α (phospho-eIF2α, activating transcription factor 4 (ATF4 and GADD153 in tumor tissues. In conclusion, we for the first time provide important evidence to support the involvement of ERS in the induction of apoptosis in pancreatic cancer cells by capsaicin.

  20. [Effect of endoplasmic reticulum stress in trophocytes on the pathogenesis of intrahepatic cholestasis of pregnancy].

    Science.gov (United States)

    Yu, Y; Zhou, C L; Yu, T T; Han, X J; Shi, H Y; Wang, H Z; Shen, J J; He, J

    2017-06-25

    Objective: To evaluate the effect of endoplasmic reticulum stress in trophocytes, in patients with intrahepatic cholestasis of pregnancy (ICP). Methods: Sixty-one pregnant women who were hospitalized in Women's Hospital, School of Medicine, Zhejiang University from January to December 2015 were recruited. Thirty-one women who were diagnosed as ICP were defined as the ICP group and 30 healthy pregnant women were defined as the control group. The localization and expression intensity of glucose regulated protein 78 (GRP-78) in placental tissues were detected by immunohistochemistry technique. Electronic microscope was used to observe ultra-microstructure change of the endoplasmic reticulum in trophocytes and cell line Swan71. Reverse transcription (RT)-PCR and western blot were used to investigate the expression of GRP-78 mRNA and protein in Swan 71 cell. Results: (1) GRP-78 protein was mainly expressed in the cytoplasm of cytotrophoblasts and syncytiotrophoblasts. The protein expression of GRP-78 in placentas of the ICP group (13.2±2.4) was significantly higher than that in the control group (7.8±1.3, Pstress of trophocytes may be involved in the pathogenesis of ICP.

  1. Hepatic Amiodarone Lipotoxicity Is Ameliorated by Genetic and Pharmacological Inhibition of Endoplasmatic Reticulum Stress.

    Science.gov (United States)

    Erez, Noam; Hubel, Einav; Avraham, Roy; Cohen, Raya; Fishman, Sigal; Bantel, Heike; Manns, Michael; Tirosh, Boaz; Zvibel, Isabel; Shibolet, Oren

    2017-10-01

    Amiodarone is a commonly used antiarrhythmic drug and can cause liver steatosis. We investigated the role of endoplasmic reticulum (ER) stress/unfolded protein response in the pathogenesis of amiodarone-induced steatosis. Amiodarone-induced liver injury was obtained by 1 intraperitoneal injection to wild-type (WT) or C/EBP homologous protein knock-out mice (Ddit3-/-). Amiodarone directly reduced intracellular ATP and Ca2+ in hepatocytes invitro, inducing ER stress and lipid accumulation. In vivo, amiodarone-driven liver damage and lipid accumulation was accompanied by activation of ER stress/unfolded protein response, as demonstrated by up-regulation of genes encoding key ER stress mediators and by phosphorylation of eIF2α. In contrast to WT mice, Ddit3-/- mice were protected from amiodarone-induced ER stress and lipid accumulation. Importantly, amiodarone-induced lipid accumulation was not mediated by de novo hepatic lipogenesis, increased adipose tissue lipolysis or increased hepatic uptake of triglycerides or free fatty acids. Rather, amiodarone strongly increased hepatic mRNA expression of lipid droplet proteins, particularly Cidea and Cidec, in WT, but less so in Ddit3-/- mice, suggesting a link between ER stress and increased triglyceride storage. Moreover, while insulin attenuated amiodarone-induced phosphorylation of hormone sensitive lipase (HSL) in WT, it did not affect pHSL in Ddit3-/-, indicating increased lipolysis and therefore reduced lipid accumulation in these mice. Finally, ER stress attenuation using 2 different pharmacological chaperones reduced lipid accumulation, accompanied by reduced mRNA expression of Cidec. In conclusion, amiodarone-induced ER stress drives liver steatosis and may be considered for therapeutic targeting. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  2. Redox signaling via the molecular chaperone BiP protects cells against endoplasmic reticulum-derived oxidative stress

    Science.gov (United States)

    Wang, Jie; Pareja, Kristeen A; Kaiser, Chris A; Sevier, Carolyn S

    2014-01-01

    Oxidative protein folding in the endoplasmic reticulum (ER) has emerged as a potentially significant source of cellular reactive oxygen species (ROS). Recent studies suggest that levels of ROS generated as a byproduct of oxidative folding rival those produced by mitochondrial respiration. Mechanisms that protect cells against oxidant accumulation within the ER have begun to be elucidated yet many questions still remain regarding how cells prevent oxidant-induced damage from ER folding events. Here we report a new role for a central well-characterized player in ER homeostasis as a direct sensor of ER redox imbalance. Specifically we show that a conserved cysteine in the lumenal chaperone BiP is susceptible to oxidation by peroxide, and we demonstrate that oxidation of this conserved cysteine disrupts BiP's ATPase cycle. We propose that alteration of BiP activity upon oxidation helps cells cope with disruption to oxidative folding within the ER during oxidative stress. DOI: http://dx.doi.org/10.7554/eLife.03496.001 PMID:25053742

  3. Fluoride-elicited developmental testicular toxicity in rats: Roles of endoplasmic reticulum stress and inflammatory response

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shun [Department of Environmental Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan 430030, Hubei (China); Jiang, Chunyang [Department of Environmental Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan 430030, Hubei (China); Department of Thoracic Surgery, Tianjin Union Medicine Centre, 190 Jieyuan Road, Hongqiao District, Tianjin 300121, Tianjin (China); Liu, Hongliang [Tianjin Center for Disease Control and Prevention, Huayue Road 6, Hedong Region, Tianjin 300011, Tianjin (China); Guan, Zhizhong [Department of Pathology, Guiyang Medical College, Guiyang 550004, Guizhou (China); Zeng, Qiang [Tianjin Center for Disease Control and Prevention, Huayue Road 6, Hedong Region, Tianjin 300011, Tianjin (China); Zhang, Cheng; Lei, Rongrong; Xia, Tao; Gao, Hui; Yang, Lu; Chen, Yihu; Wu, Xue; Zhang, Xiaofei [Department of Environmental Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan 430030, Hubei (China); Cui, Yushan; Yu, Linyu [Tianjin Center for Disease Control and Prevention, Huayue Road 6, Hedong Region, Tianjin 300011, Tianjin (China); Wang, Zhenglun [Department of Environmental Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan 430030, Hubei (China); Wang, Aiguo, E-mail: wangaiguo@mails.tjmu.edu.cn [Department of Environmental Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan 430030, Hubei (China)

    2013-09-01

    Long-term excessive fluoride intake is known to be toxic and can damage a variety of organs and tissues in the human body. However, the molecular mechanisms underlying fluoride-induced male reproductive toxicity are not well understood. In this study, we used a rat model to simulate the situations of human exposure and aimed to evaluate the roles of endoplasmic reticulum (ER) stress and inflammatory response in fluoride-induced testicular injury. Sprague–Dawley rats were administered with sodium fluoride (NaF) at 25, 50 and 100 mg/L via drinking water from pre-pregnancy to gestation, birth and finally to post-puberty. And then the testes of male offspring were studied at 8 weeks of age. Our results demonstrated that fluoride treatment increased MDA accumulation, decreased SOD activity, and enhanced germ cell apoptosis. In addition, fluoride elevated mRNA and protein levels of glucose-regulated protein 78 (GRP78), inositol requiring ER-to-nucleus signal kinase 1 (IRE1), and C/EBP homologous protein (CHOP), indicating activation of ER stress signaling. Furthermore, fluoride also induced testicular inflammation, as manifested by gene up-regulation of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), in a nuclear factor-κB (NF-κB)-dependent manner. These were associated with marked histopathological lesions including injury of spermatogonia, decrease of spermatocytes and absence of elongated spermatids, as well as severe ultrastructural abnormalities in testes. Taken together, our results provide compelling evidence that ER stress and inflammation would be novel and significant mechanisms responsible for fluoride-induced disturbance of spermatogenesis and germ cell loss in addition to oxidative stress. - Highlights: • We used a rat model to simulate the situations of human fluoride (F) exposure. • Developmental F exposure induces testicular damage related with oxidative stress.

  4. Endoplasmic Reticulum Stress Cooperates in Zearalenone-Induced Cell Death of RAW 264.7 Macrophages

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    Fenglei Chen

    2015-08-01

    Full Text Available Zearalenone (ZEA is a fungal mycotoxin that causes cell apoptosis and necrosis. However, little is known about the molecular mechanisms of ZEA toxicity. The objective of this study was to explore the effects of ZEA on the proliferation and apoptosis of RAW 264.7 macrophages and to uncover the signaling pathway underlying the cytotoxicity of ZEA in RAW 264.7 macrophages. This study demonstrates that the endoplasmic reticulum (ER stress pathway cooperated in ZEA-induced cell death of the RAW 264.7 macrophages. Our results show that ZEA treatment reduced the viability of RAW 264.7 macrophages in a dose- and time-dependent manner as shown by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay (MTT and flow cytometry assay. Western blots analysis revealed that ZEA increased the expression of glucose-regulated protein 78 (GRP78 and CCAAT/enhancer binding protein homologous protein (CHOP, two ER stress-related marker genes. Furthermore, treating the cells with the ER stress inhibitors 4-phenylbutyrate (4-PBA or knocking down CHOP, using lentivirus encoded short hairpin interfering RNAs (shRNAs, significantly diminished the ZEA-induced increases in GRP78 and CHOP, and cell death. In summary, our results suggest that ZEA induces the apoptosis and necrosis of RAW 264.7 macrophages in a dose- and time-dependent manner via the ER stress pathway in which the activation of CHOP plays a critical role.

  5. Endoplasmic Reticulum Stress Cooperates in Zearalenone-Induced Cell Death of RAW 264.7 Macrophages.

    Science.gov (United States)

    Chen, Fenglei; Li, Qian; Zhang, Zhe; Lin, Pengfei; Lei, Lanjie; Wang, Aihua; Jin, Yaping

    2015-08-20

    Zearalenone (ZEA) is a fungal mycotoxin that causes cell apoptosis and necrosis. However, little is known about the molecular mechanisms of ZEA toxicity. The objective of this study was to explore the effects of ZEA on the proliferation and apoptosis of RAW 264.7 macrophages and to uncover the signaling pathway underlying the cytotoxicity of ZEA in RAW 264.7 macrophages. This study demonstrates that the endoplasmic reticulum (ER) stress pathway cooperated in ZEA-induced cell death of the RAW 264.7 macrophages. Our results show that ZEA treatment reduced the viability of RAW 264.7 macrophages in a dose- and time-dependent manner as shown by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay (MTT) and flow cytometry assay. Western blots analysis revealed that ZEA increased the expression of glucose-regulated protein 78 (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP), two ER stress-related marker genes. Furthermore, treating the cells with the ER stress inhibitors 4-phenylbutyrate (4-PBA) or knocking down CHOP, using lentivirus encoded short hairpin interfering RNAs (shRNAs), significantly diminished the ZEA-induced increases in GRP78 and CHOP, and cell death. In summary, our results suggest that ZEA induces the apoptosis and necrosis of RAW 264.7 macrophages in a dose- and time-dependent manner via the ER stress pathway in which the activation of CHOP plays a critical role.

  6. Critical Role of Endoplasmic Reticulum Stress in Cognitive Impairment Induced by Microcystin-LR

    Directory of Open Access Journals (Sweden)

    Fei Cai

    2015-11-01

    Full Text Available Recent studies showed that cyanobacteria-derived microcystin-leucine-arginine (MCLR can cause hippocampal pathological damage and trigger cognitive impairment; but the underlying mechanisms have not been well understood. The objective of the present study was to investigate the mechanism of MCLR-induced cognitive deficit; with a focus on endoplasmic reticulum (ER stress. The Morris water maze test and electrophysiological study demonstrated that MCLR caused spatial memory injury in male Wistar rats; which could be inhibited by ER stress blocker; tauroursodeoxycholic acid (TUDCA. Meanwhile; real-time polymerase chain reaction (real-time PCR and immunohistochemistry demonstrated that the expression level of the 78-kDa glucose-regulated protein (GRP78; C/EBP homologous protein (CHOP and caspase 12 were significantly up-regulated. These effects were rescued by co-administration of TUDCA. In agreement with this; we also observed that treatment of rats with TUDCA blocked the alterations in ER ultrastructure and apoptotic cell death in CA1 neurons from rats exposed to MCLR. Taken together; the present results suggested that ER stress plays an important role in potential memory impairments in rats treated with MCLR; and amelioration of ER stress may serve as a novel strategy to alleviate damaged cognitive function triggered by MCLR.

  7. Mitochondrial cholesterol accumulation in alcoholic liver disease: Role of ASMase and endoplasmic reticulum stress.

    Science.gov (United States)

    Marí, Montserrat; Morales, Albert; Colell, Anna; García-Ruiz, Carmen; Fernández-Checa, Jose C

    2014-01-01

    Alcoholic liver disease (ALD) is a major cause of chronic liver disease and a growing health concern in theworld. While the pathogenesis of ALD is poorly characterized key players identified in experimental models and patients, such as perturbations in mitochondrial structure and function, selective loss of antioxidant defense and susceptibility to inflammatory cytokines, contribute to ALD progression. Both oxidative stress and mitochondrial dysfunction compromise essential cellular functions and energy generation and hence are important pathogenic mechanisms of ALD. An important process mediating the mitochondrial disruption induced by alcohol intake is the trafficking of cholesterol to mitochondria, mediated by acid sphingomyelinase-induced endoplasmic reticulum stress, which contributes to increased cholesterol synthesis and StARD1upregulation. Mitochondrial cholesterol accumulation not only sensitizes to oxidative stress but it can contribute to the metabolic reprogramming in ALD, manifested by activation of the hypoxia inducible transcription factor 1 and stimulation of glycolysis and lactate secretion. Thus, a better understanding of the mechanisms underlying alcohol-mediated mitochondrial impairment and oxidative stress may lead to the identification of novel treatments for ALD. The present review briefly summarizes current knowledge on the cellular and molecular mechanisms contributing to alcohol-induced mitochondrial dysfunction and cholesterol accumulation and provides insights for potential therapeutic targets in ALD.

  8. Hyperactivity of the Ero1α Oxidase Elicits Endoplasmic Reticulum Stress but No Broad Antioxidant Response

    DEFF Research Database (Denmark)

    Hansen, Henning Gram; Schmidt, Jonas Damgard; Soltoft, Cecilie Lutzen

    2012-01-01

    Oxidizing equivalents for the process of oxidative protein folding in the endoplasmic reticulum (ER) of mammalian cells are mainly provided by the Ero1α oxidase. The molecular mechanisms that regulate Ero1α activity in order to harness its oxidative power are quite well understood. However......, the overall cellular response to oxidative stress generated by Ero1α in the lumen of the mammalian ER is poorly characterized. Here we investigate the effects of overexpressing a hyperactive mutant (C104A/C131A) of Ero1α. We show that Ero1α hyperactivity leads to hyperoxidation of the ER oxidoreductase ERp57...... the cellular glutathione redox buffer, we conclude that the observed effects of Ero1α-C104A/C131A overexpression are likely caused by an oxidative perturbation of the ER glutathione redox buffer. In accordance, we show that Ero1α hyperactivity affects cell viability when cellular glutathione levels...

  9. Salubrinal Alleviates Pressure Overload-Induced Cardiac Hypertrophy by Inhibiting Endoplasmic Reticulum Stress Pathway

    Science.gov (United States)

    Rani, Shilpa; Sreenivasaiah, Pradeep Kumar; Cho, Chunghee; Kim, Do Han

    2017-01-01

    Pathological hypertrophy of the heart is closely associated with endoplasmic reticulum stress (ERS), leading to maladaptations such as myocardial fibrosis, induction of apoptosis, and cardiac dysfunctions. Salubrinal is a known selective inhibitor of protein phosphatase 1 (PP1) complex involving dephosphorylation of phospho-eukaryotic translation initiation factor 2 subunit (p-eIF2)-α, the key signaling process in the ERS pathway. In this study, the effects of salubrinal were examined on cardiac hypertrophy using the mouse model of transverse aortic constriction (TAC) and cell model of neonatal rat ventricular myocytes (NRVMs). Treatment of TAC-induced mice with salubrinal (0.5 mg·kg−1·day−1) alleviated cardiac hypertrophy and tissue fibrosis. Salubrinal also alleviated hypertrophic growth in endothelin 1 (ET1)-treated NRVMs. Therefore, the present results suggest that salubrinal may be a potentially efficacious drug for treating pathological cardiac remodeling. PMID:28152298

  10. Endoplasmic reticulum stress induces different molecular structural alterations in human dilated and ischemic cardiomyopathy.

    Directory of Open Access Journals (Sweden)

    Ana Ortega

    Full Text Available BACKGROUND: The endoplasmic reticulum (ER is a multifunctional organelle responsible for the synthesis and folding of proteins as well as for signalling and calcium storage, that has been linked to the contraction-relaxation process. Perturbations of its homeostasis activate a stress response in diseases such as heart failure (HF. To elucidate the alterations in ER molecular components, we analyze the levels of ER stress and structure proteins in human dilated (DCM and ischemic (ICM cardiomyopathies, and its relationship with patient's functional status. METHODS AND RESULTS: We examined 52 explanted human hearts from DCM (n = 21 and ICM (n = 21 subjects and 10 non-failing hearts as controls. Our results showed specific changes in stress (IRE1, p<0.05; p-IRE1, p<0.05 and structural (Reticulon 1, p<0.01 protein levels. The stress proteins GRP78, XBP1 and ATF6 as well as the structural proteins RRBP1, kinectin, and Nogo A and B, were upregulated in both DCM and ICM patients. Immunofluorescence results were concordant with quantified Western blot levels. Moreover, we show a novel relationship between stress and structural proteins. RRBP1, involved in procollagen synthesis and remodeling, was related with left ventricular function. CONCLUSIONS: In the present study, we report the existence of alterations in ER stress response and shaping proteins. We show a plausible effect of the ER stress on ER structure in a suitable sample of DCM and ICM subjects. Patients with higher values of RRBP1 had worse left ventricular function.

  11. Sulfur mustard induces an endoplasmic reticulum stress response in the mouse ear vesicant model

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Yoke-Chen; Wang, James D. [Rutgers University, Pharmacology and Toxicology, 170 Frelinghuysen Rd, Piscataway, NJ 08854 (United States); Svoboda, Kathy K. [Texas A and M University, Baylor College of Dentistry, Center for Craniofacial Research 3302 Gaston Ave, Dallas, Texas 75246 (United States); Casillas, Robert P. [MRIGlobal, 425 Volker Boulevard, Kansas City, MO 64110 (United States); Laskin, Jeffrey D. [UMDNJ-Robert Wood Johnson Medical School, Environmental and Occupational Medicine, 170 Frelinghuysen Rd, Piscataway, NJ 08854 (United States); Gordon, Marion K. [Rutgers University, Pharmacology and Toxicology, 170 Frelinghuysen Rd, Piscataway, NJ 08854 (United States); Gerecke, Donald R., E-mail: gerecke@eohsi.rutgers.edu [Rutgers University, Pharmacology and Toxicology, 170 Frelinghuysen Rd, Piscataway, NJ 08854 (United States)

    2013-04-15

    The endoplasmic reticulum (ER) stress response is a cell survival pathway upregulated when cells are under severe stress. Severely damaged mouse ear skin exposed to the vesicant, sulfur mustard (bis-2-chloroethyl sulfide, SM), resulted in increased expression of ER chaperone proteins that accompany misfolded and incorrectly made proteins targeted for degradation. Time course studies with SM using the mouse ear vesicant model (MEVM) showed progressive histopathologic changes including edema, separation of the epidermis from the dermis, persistent inflammation, upregulation of laminin γ2 (one of the chains of laminin-332, a heterotrimeric skin glycoprotein required for wound repair), and delayed wound healing from 24 h to 168 h post exposure. This was associated with time related increased expression of the cell survival ER stress marker, GRP78/BiP, and the ER stress apoptosis marker, GADD153/CHOP, suggesting simultaneous activation of both cell survival and non-mitochondrial apoptosis pathways. Dual immunofluorescence labeling of a keratinocyte migration promoting protein, laminin γ2 and GRP78/BIP, showed colocalization of the two molecules 72 h post exposure indicating that the laminin γ2 was misfolded after SM exposure and trapped within the ER. Taken together, these data show that ER stress is induced in mouse skin within 24 h of vesicant exposure in a defensive response to promote cell survival; however, it appears that this response is rapidly overwhelmed by the apoptotic pathway as a consequence of severe SM-induced injury. - Highlights: ► We demonstrated ER stress response in the mouse ear vesicant model. ► We described the asymmetrical nature of wound repair in the MEVM. ► We identified the distribution of various ER stress markers in the MEVM.

  12. Uterine endoplasmic reticulum stress and its unfolded protein response may regulate caspase 3 activation in the pregnant mouse uterus.

    Directory of Open Access Journals (Sweden)

    Arvind Suresh

    Full Text Available We have previously proposed that uterine caspase-3 may modulate uterine contractility in a gestationally regulated fashion. The objective of this study was to determine the mechanism by which uterine caspase-3 is activated and consequently controlled in the pregnant uterus across gestation. Utilizing the mouse uterus as our gestational model we examined the intrinsic and extrinsic apoptotic signaling pathways and the endoplasmic reticulum stress response as potential activators of uterine caspase-3 at the transcriptional and translational level. Our study revealed robust activation of the uterine myocyte endoplasmic reticulum stress response and its adaptive unfolded protein response during pregnancy coinciding respectively with increased uterine caspase-3 activity and its withdrawal to term. In contrast the intrinsic and extrinsic apoptotic signaling pathways remained inactive across gestation. We speculate that physiological stimuli experienced by the pregnant uterus likely potentiates the uterine myocyte endoplasmic reticulum stress response resulting in elevated caspase-3 activation, which is isolated to the pregnant mouse myometrium. However as term approaches, activation of an elevated adaptive unfolded protein response acts to limit the endoplasmic reticulum stress response inhibiting caspase-3 resulting in its decline towards term. We speculate that these events have the capacity to regulate gestational length in a caspase-3 dependent manner.

  13. Uterine endoplasmic reticulum stress and its unfolded protein response may regulate caspase 3 activation in the pregnant mouse uterus.

    Science.gov (United States)

    Suresh, Arvind; Subedi, Kalpana; Kyathanahalli, Chandrashekara; Jeyasuria, Pancharatnam; Condon, Jennifer C

    2013-01-01

    We have previously proposed that uterine caspase-3 may modulate uterine contractility in a gestationally regulated fashion. The objective of this study was to determine the mechanism by which uterine caspase-3 is activated and consequently controlled in the pregnant uterus across gestation. Utilizing the mouse uterus as our gestational model we examined the intrinsic and extrinsic apoptotic signaling pathways and the endoplasmic reticulum stress response as potential activators of uterine caspase-3 at the transcriptional and translational level. Our study revealed robust activation of the uterine myocyte endoplasmic reticulum stress response and its adaptive unfolded protein response during pregnancy coinciding respectively with increased uterine caspase-3 activity and its withdrawal to term. In contrast the intrinsic and extrinsic apoptotic signaling pathways remained inactive across gestation. We speculate that physiological stimuli experienced by the pregnant uterus likely potentiates the uterine myocyte endoplasmic reticulum stress response resulting in elevated caspase-3 activation, which is isolated to the pregnant mouse myometrium. However as term approaches, activation of an elevated adaptive unfolded protein response acts to limit the endoplasmic reticulum stress response inhibiting caspase-3 resulting in its decline towards term. We speculate that these events have the capacity to regulate gestational length in a caspase-3 dependent manner.

  14. The endoplasmic reticulum stress/unfolded protein response in gliomagenesis, tumor progression and as a therapeutic target in glioblastoma

    NARCIS (Netherlands)

    Peñaranda Fajardo, Natalia; Meijer, Coby; Kruyt, Frank A. E.

    2016-01-01

    Endoplasmic reticulum (ER) stress disrupts among others protein homeostasis in cells leading to the activation of the unfolded protein response (UPR) that is crucial for restoring this balance and cell survival. Hypoxia, reactive oxygen species and nutrient deprivation, conditions commonly present i

  15. Endoplasmic reticulum stress in complex atypical hyperplasia as a possible predictor of occult carcinoma and progestin response.

    Science.gov (United States)

    Tierney, Katherine E; Ji, Lingyun; Dralla, Shannon S; Yoo, Eunjeong; Yessaian, Annie; Pham, Huyen Q; Roman, Lynda; Sposto, Richard; Mhawech-Fauceglia, Paulette; Lin, Yvonne G

    2016-12-01

    Glucose-regulated protein (GRP)-78, the key regulator of endoplasmic reticulum (ER) stress, is associated with endometrial cancer (EC) development and progression. However, its role in the continuum from complex atypical hyperplasia (CAH) to EC is unknown and the focus of this study.

  16. Endoplasmic reticulum stress inhibits collagen synthesis independent of collagen-modifying enzymes in different chondrocyte populations and dermal fibroblasts

    NARCIS (Netherlands)

    Vonk, Lucienne A.; Doulabi, Behrouz Zandieh; Huang, Chun-Ling; Helder, Marco N.; Everts, Vincent; Bank, Ruud A.

    2010-01-01

    Chondrocytes respond to glucose deprivation with a decreased collagen synthesis due to disruption of a proper functioning of the endoplasmic reticulum (ER): ER stress. Since the mechanisms involved in the decreased synthesis are unknown, we have investigated whether chaperones and collagen-modifying

  17. The Possible Potentiating Role of Endoplasmic Reticulum Stress Response Inhibitors in Trans-Differentiation of white to Brown Adipocytes

    Directory of Open Access Journals (Sweden)

    Ali Mohammad Sharifi

    2012-01-01

    Full Text Available The brown adipose tissue (BAT is an organ with the specialised function of intracellular fat oxidation; in other words, brown fat points to a potential natural tool by which energy expenditure is being stimulated. Obesity is a serious illness which can lead to many medical complications such as cardiovascular disorders. The BAT production, therefore, could be a promising therapeutic strategy for managing obesity. While different approaches have been examined to generate brown adipocytes from various precursor cells, no study has proposed an efficient procedure for direct trans-differentiation of white to brown adipocytes. Bone morphogenic protein (BMP-7 is a possible potential agent by which most of the main factors involved in induction of brown adipocytogenesis such as early regulators of brown fat fate, positive regulatory domain containing 16 (PRDM16 and peroxisome proliferator-activated receptor gamma (PPARγ coactivator-1 alpha (PGC-1α are stimulated, but the rate of success was not so promising. It has been documented that mature white adipocytes exert endoplasmic reticulum stress response (ESR and consequently unfolded protein response (UPR becomes activated for the purpose of ESR recovery since the ESR exceeds the capacity of UPR to overcome the imposed stress, and in turn disables the cell to manage the protein synthesis cascade including those required for BMP-7 induction of brown adipogenesis. This was performed using three main ESR sensors: PKR-like endoplasmic reticulum kinase (PERK, inositol requiring enzyme-1 (IRE-1 and activating transcription factor 6 alpha (ATF-6α resulting in attenuation of protein translation by blocking the activation of transcriptional machinery of UPR genes and the cell behaviour would also be changed towards apoptosis.It may suggest and propose the hypothesis that pretreatment of the white adipocyte with an ESR inhibitor such as salubrinal by reducing ESR and turning on the protein synthesis machinery

  18. The Herbal Medicine Cordyceps sinensis Protects Pancreatic Beta Cells from Streptozotocin-Induced Endoplasmic Reticulum Stress.

    Science.gov (United States)

    Liu, Hong; Cao, Diyong; Liu, Hua; Liu, Xinghai; Mai, Wenli; Lan, Haitao; Huo, Wen; Zheng, Qian

    2016-08-01

    Our previous work found that Cordyceps sinensis (CS) improves the activity and secretory function of pancreatic islet beta cells. The objective was to observe a further possible role of CS in the protection of insulin-secreting cells. A rat model of type 2 diabetes mellitus was developed with streptozotocin (STZ) and a high-energy fat diet (HFD). CS was administered in the successful model of rats with type 2 diabetes. After 4 weeks, the biochemistry index of blood samples was measured, and pathologic observation was performed by immunohistochemistry. In the rats with type 2 diabetes induced by a HFD and STZ, the levels of fasting blood glucose and fasting insulin were elevated, and the insulin sensitivity index was decreased. Pathologic examination found an increased number of apoptotic cells, an elevated protein expression of pro-apoptotic C/EBP homologous protein (CHOP) and an increased c-Jun level by means of JNK phosphorylation, responsive to the endoplasmic reticulum stress of islet beta cells. With treatment by CS for 4 weeks, the elevated levels of both fasting blood glucose and fasting insulin in the rats with type 2 diabetes were significantly lower, and the decreased insulin sensitivity index was reversed. Compared to the control rats with type 2 diabetes, CS application significantly reduced the number of apoptotic cells and decreased protein expression of both CHOP and c-Jun. The herbal compound CS could protect pancreatic beta cells from the pro-apoptotic endoplasmic reticulum stress induced by HFD-STZ. This suggests an alternative approach to treating type 2 diabetes. Copyright © 2016 Canadian Diabetes Association. Published by Elsevier Inc. All rights reserved.

  19. Excessive training is associated with endoplasmic reticulum stress but not apoptosis in the hypothalamus of mice.

    Science.gov (United States)

    Pinto, Ana Paula; da Rocha, Alisson Luiz; Pereira, Bruno Cesar; Oliveira, Luciana da Costa; Morais, Gustavo Paroschi; Moura, Leandro Pereira; Ropelle, Eduardo Rochete; Pauli, José Rodrigo; da Silva, Adelino Sanchez Ramos

    2017-04-01

    Downhill running-based overtraining model increases the hypothalamic levels of IL-1β, TNF-α, SOCS3, and pSAPK-JNK. The aim of the present study was to verify the effects of 3 overtraining protocols on the levels of BiP, pIRE-1 (Ser724), pPERK (Thr981), pelF2α (Ser52), ATF-6, GRP-94, caspase 4, caspase 12, pAKT (Ser473), pmTOR (Ser2448), and pAMPK (Thr172) proteins in the mouse hypothalamus. The mice were randomized into the control, overtrained by downhill running (OTR/down), overtrained by uphill running (OTR/up), and overtrained by running without inclination (OTR) groups. After the overtraining protocols (i.e., at the end of week 8), hypothalamus was removed and used for immunoblotting. The OTR/down group exhibited increased levels of all of the analyzed endoplasmic reticulum stress markers in the hypothalamus at the end of week 8. The OTR/up and OTR groups exhibited increased levels of BiP, pIRE-1 (Ser724), and pPERK (Thr981) in the hypothalamus at the end of week 8. There were no significant differences in the levels of caspase 4, caspase 12, pAKT (Ser473), pmTOR (Ser2448), and pAMPK (Thr172) between the experimental groups at the end of week 8. In conclusion, the 3 overtraining protocols increased the endoplasmic reticulum stress at the end of week 8.

  20. Calcineurin is involved in cardioprotection induced by ischemic postconditioning through attenuating endoplasmic reticulum stress

    Institute of Scientific and Technical Information of China (English)

    CHEN Yi-hong; WU Xu-dong; YAO Shu-tong; SUN Seng; LIU Xiu-hua

    2011-01-01

    Background Ischemic postconditioning (I-postC) is a newly discovered and more amenable cardioprotective strategy capable of protecting the myocardium from ischemia/reperfusion (I/R) injury.Endoplasmic reticulum (ER) is a principal site for secretary protein synthesis and calcium storage.Myocardial I/R causes ER stress and emerging studies suggest that the cardioprotection has been linked to the modulation of ER stress.The aim of the present study was to determine whether cardioprotection of I-postC involves reduction in ER stress through calcineurin pathway.Methods In the in vivo model of rat myocardial I/R,myocardial infarct size was measured by triphenyltetrazolium chloride (TTC) staining and apoptosis was detected using terminal eoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay.Expression of calreticulin,C/EBP homologous protein (CHOP),caspase-12,and activation of caspase-12 in myocardium were detected by Western blotting.The activity and expression of calcineurin in myocardium were also detected.Results I-postC protected the I/R heart against apoptosis,myocardial infarction,and leakage of lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB).I-postC suppressed I/R-induced ER stress,as shown by a decrease in the expression of calreticulin and CHOP,and caspase-12 activation.I-postC downregulated calcineurin activation in myocardium subjected to I/R.Conclusion I-postC protects myocardium from I/R injury by suppressing ER stress and calcineurin pathways are not associated with the I-postC-induced suppression of ER stress-related apoptosis.

  1. Acidosis Activates Endoplasmic Reticulum Stress Pathways through GPR4 in Human Vascular Endothelial Cells

    Directory of Open Access Journals (Sweden)

    Lixue Dong

    2017-01-01

    Full Text Available Acidosis commonly exists in the tissue microenvironment of various pathophysiological conditions such as tumors, inflammation, ischemia, metabolic disease, and respiratory disease. For instance, the tumor microenvironment is characterized by acidosis and hypoxia due to tumor heterogeneity, aerobic glycolysis (the “Warburg effect”, and the defective vasculature that cannot efficiently deliver oxygen and nutrients or remove metabolic acid byproduct. How the acidic microenvironment affects the function of blood vessels, however, is not well defined. GPR4 (G protein-coupled receptor 4 is a member of the proton-sensing G protein-coupled receptors and it has high expression in endothelial cells (ECs. We have previously reported that acidosis induces a broad inflammatory response in ECs. Acidosis also increases the expression of several endoplasmic reticulum (ER stress response genes such as CHOP (C/EBP homologous protein and ATF3 (activating transcription factor 3. In the current study, we have examined acidosis/GPR4- induced ER stress pathways in human umbilical vein endothelial cells (HUVEC and other types of ECs. All three arms of the ER stress/unfolded protein response (UPR pathways were activated by acidosis in ECs as an increased expression of phosphorylated eIF2α (eukaryotic initiation factor 2α, phosphorylated IRE1α (inositol-requiring enzyme 1α, and cleaved ATF6 upon acidic pH treatment was observed. The expression of other downstream mediators of the UPR, such as ATF4, ATF3, and spliced XBP-1 (X box-binding protein 1, was also induced by acidosis. Through genetic and pharmacological approaches to modulate the expression level or activity of GPR4 in HUVEC, we found that GPR4 plays an important role in mediating the ER stress response induced by acidosis. As ER stress/UPR can cause inflammation and cell apoptosis, acidosis/GPR4-induced ER stress pathways in ECs may regulate vascular growth and inflammatory response in the acidic

  2. The Batten disease gene CLN3 confers resistance to endoplasmic reticulum stress induced by tunicamycin

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Dan, E-mail: danw@bjmu.edu.cn [Department of Medical Genetics, Peking University Health Science Center, No 38 Xueyuan Road, Haidian district, Beijing 100191 (China); Liu, Jing; Wu, Baiyan [Department of Medical Genetics, Peking University Health Science Center, No 38 Xueyuan Road, Haidian district, Beijing 100191 (China); Tu, Bo; Zhu, Weiguo [Department of Biochemistry and Molecular Biology, Peking University Health Science Center, No 38 Xueyuan Road, Haidian district, Beijing 100191 (China); Luo, Jianyuan, E-mail: jluo@som.umaryland.edu [Department of Medical Genetics, Peking University Health Science Center, No 38 Xueyuan Road, Haidian district, Beijing 100191 (China); Department of Medical and Research Technology, School of Medicine, University of Maryland, Baltimore 21201 (United States)

    2014-04-25

    Highlights: • The work reveals a protective properties of CLN3 towards TM-induced apoptosis. • CLN3 regulates expression of the GRP78 and the CHOP in response to the ER stress. • CLN3 plays a specific role in the ERS response. - Abstract: Mutations in CLN3 gene cause juvenile neuronal ceroid lipofuscinosis (JNCL or Batten disease), an early-onset neurodegenerative disorder that is characterized by the accumulation of ceroid lipofuscin within lysosomes. The function of the CLN3 protein remains unclear and is presumed to be related to Endoplasmic reticulum (ER) stress. To investigate the function of CLN3 in the ER stress signaling pathway, we measured proliferation and apoptosis in cells transfected with normal and mutant CLN3 after treatment with the ER stress inducer tunicamycin (TM). We found that overexpression of CLN3 was sufficient in conferring increased resistance to ER stress. Wild-type CLN3 protected cells from TM-induced apoptosis and increased cell proliferation. Overexpression of wild-type CLN3 enhanced expression of the ER chaperone protein, glucose-regulated protein 78 (GRP78), and reduced expression of the proapoptotic protein CCAAT/-enhancer-binding protein homologous protein (CHOP). In contrast, overexpression of mutant CLN3 or siRNA knockdown of CLN3 produced the opposite effect. Together, our data suggest that the lack of CLN3 function in cells leads to a failure of management in the response to ER stress and this may be the key deficit in JNCL that causes neuronal degeneration.

  3. Endoplasmic reticulum stress-sensing mechanism is activated in Entamoeba histolytica upon treatment with nitric oxide.

    Directory of Open Access Journals (Sweden)

    Julien Santi-Rocca

    Full Text Available The Endoplasmic Reticulum stores calcium and is a site of protein synthesis and modification. Changes in ER homeostasis lead to stress responses with an activation of the unfolded protein response (UPR. The Entamoeba histolytica endomembrane system is simple compared to those of higher eukaryotes, as a canonical ER is not observed. During amoebiasis, an infection of the human intestine and liver by E. histolytica, nitric oxide (NO triggers an apoptotic-like event preceded by an impairment of energy production and a loss of important parasite pathogenic features. We address the question of how this ancient eukaryote responds to stress induced by immune components (i.e. NO and whether stress leads to ER changes and subsequently to an UPR. Gene expression analysis suggested that NO triggers stress responses marked by (i dramatic up-regulation of hsp genes although a bona fide UPR is absent; (ii induction of DNA repair and redox gene expression and iii up-regulation of glycolysis-related gene expression. Enzymology approaches demonstrate that NO directly inhibits glycolysis and enhance cysteine synthase activity. Using live imaging and confocal microscopy we found that NO dramatically provokes extensive ER fragmentation. ER fission in E. histolytica appears as a protective response against stress, as it has been recently proposed for neuron self-defense during neurologic disorders. Chronic ER stress is also involved in metabolic diseases including diabetes, where NO production reduces ER calcium levels and activates cell death. Our data highlighted unique cellular responses of interest to understand the mechanisms of parasite death during amoebiasis.

  4. Acidosis Activates Endoplasmic Reticulum Stress Pathways through GPR4 in Human Vascular Endothelial Cells.

    Science.gov (United States)

    Dong, Lixue; Krewson, Elizabeth A; Yang, Li V

    2017-01-27

    Acidosis commonly exists in the tissue microenvironment of various pathophysiological conditions such as tumors, inflammation, ischemia, metabolic disease, and respiratory disease. For instance, the tumor microenvironment is characterized by acidosis and hypoxia due to tumor heterogeneity, aerobic glycolysis (the "Warburg effect"), and the defective vasculature that cannot efficiently deliver oxygen and nutrients or remove metabolic acid byproduct. How the acidic microenvironment affects the function of blood vessels, however, is not well defined. GPR4 (G protein-coupled receptor 4) is a member of the proton-sensing G protein-coupled receptors and it has high expression in endothelial cells (ECs). We have previously reported that acidosis induces a broad inflammatory response in ECs. Acidosis also increases the expression of several endoplasmic reticulum (ER) stress response genes such as CHOP (C/EBP homologous protein) and ATF3 (activating transcription factor 3). In the current study, we have examined acidosis/GPR4- induced ER stress pathways in human umbilical vein endothelial cells (HUVEC) and other types of ECs. All three arms of the ER stress/unfolded protein response (UPR) pathways were activated by acidosis in ECs as an increased expression of phosphorylated eIF2α (eukaryotic initiation factor 2α), phosphorylated IRE1α (inositol-requiring enzyme 1α), and cleaved ATF6 upon acidic pH treatment was observed. The expression of other downstream mediators of the UPR, such as ATF4, ATF3, and spliced XBP-1 (X box-binding protein 1), was also induced by acidosis. Through genetic and pharmacological approaches to modulate the expression level or activity of GPR4 in HUVEC, we found that GPR4 plays an important role in mediating the ER stress response induced by acidosis. As ER stress/UPR can cause inflammation and cell apoptosis, acidosis/GPR4-induced ER stress pathways in ECs may regulate vascular growth and inflammatory response in the acidic microenvironment.

  5. RIPK1 regulates survival of human melanoma cells upon endoplasmic reticulum stress through autophagy.

    Science.gov (United States)

    Luan, Qi; Jin, Lei; Jiang, Chen Chen; Tay, Kwang Hong; Lai, Fritz; Liu, Xiao Ying; Liu, Yi Lun; Guo, Su Tang; Li, Chun Ying; Yan, Xu Guang; Tseng, Hsin-Yi; Zhang, Xu Dong

    2015-01-01

    Although RIPK1 (receptor [TNFRSF]-interacting protein kinase 1) is emerging as a critical determinant of cell fate in response to cellular stress resulting from activation of death receptors and DNA damage, its potential role in cell response to endoplasmic reticulum (ER) stress remains undefined. Here we report that RIPK1 functions as an important prosurvival mechanism in melanoma cells undergoing pharmacological ER stress induced by tunicamycin (TM) or thapsigargin (TG) through activation of autophagy. While treatment with TM or TG upregulated RIPK1 and triggered autophagy in melanoma cells, knockdown of RIPK1 inhibited autophagy and rendered the cells sensitive to killing by TM or TG, recapitulating the effect of inhibition of autophagy. Consistently, overexpression of RIPK1 enhanced induction of autophagy and conferred resistance of melanoma cells to TM- or TG-induced cell death. Activation of MAPK8/JNK1 or MAPK9/JNK2, which phosphorylated BCL2L11/BIM leading to its dissociation from BECN1/Beclin 1, was involved in TM- or TG-induced, RIPK1-mediated activation of autophagy; whereas, activation of the transcription factor HSF1 (heat shock factor protein 1) downstream of the ERN1/IRE1-XBP1 axis of the unfolded protein response was responsible for the increase in RIPK1 in melanoma cells undergoing pharmacological ER stress. Collectively, these results identify upregulation of RIPK1 as an important resistance mechanism of melanoma cells to TM- or TG-induced ER stress by protecting against cell death through activation of autophagy, and suggest that targeting the autophagy-activating mechanism of RIPK1 may be a useful strategy to enhance sensitivity of melanoma cells to therapeutic agents that induce ER stress.

  6. HMGB1 induces an inflammatory response in endothelial cells via the RAGE-dependent endoplasmic reticulum stress pathway

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Ying [Department of Geriatric Medicine, Xiangya Hospital, Central South University, Changsha 410078 (China); Li, Shu-Jun [Department of Cardiovascular Medicine, Xiangya Hospital, Central South University, Changsha 410078 (China); Yang, Jian [Department of Geriatric Medicine, Xiangya Hospital, Central South University, Changsha 410078 (China); Qiu, Yuan-Zhen [Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha 410078 (China); Chen, Fang-Ping, E-mail: xychenfp@163.com [Department of Hematology, Xiangya Hospital, Central South University, Changsha 410078 (China)

    2013-09-06

    Highlights: •Mechanisms of inflammatory response induced by HMGB1 are incompletely understood. •We found that endoplasmic reticulum stress mediate the inflammatory response induced by HMGB1. •RAGE-mediated ERS pathways are involved in those processes. •We reported a new mechanism for HMGB1 induced inflammatory response. -- Abstract: The high mobility group 1B protein (HMGB1) mediates chronic inflammatory responses in endothelial cells, which play a critical role in atherosclerosis. However, the underlying mechanism is unknown. The goal of our study was to identify the effects of HMGB1 on the RAGE-induced inflammatory response in endothelial cells and test the possible involvement of the endoplasmic reticulum stress pathway. Our results showed that incubation of endothelial cells with HMGB1 (0.01–1 μg/ml) for 24 h induced a dose-dependent activation of endoplasmic reticulum stress transducers, as assessed by PERK and IRE1 protein expression. Moreover, HMGB1 also promoted nuclear translocation of ATF6. HMGB1-mediated ICAM-1 and P-selectin production was dramatically suppressed by PERK siRNA or IRE1 siRNA. However, non-targeting siRNA had no such effects. HMGB1-induced increases in ICAM-1 and P-selectin expression were also inhibited by a specific eIF2α inhibitor (salubrinal) and a specific JNK inhibitor (SP600125). Importantly, a blocking antibody specifically targeted against RAGE (anti-RAGE antibody) decreased ICAM-1, P-selectin and endoplasmic reticulum stress molecule (PERK, eIF2α, IRE1 and JNK) protein expression levels. Collectively, these novel findings suggest that HMGB1 promotes an inflammatory response by inducing the expression of ICAM-1 and P-selectin via RAGE-mediated stimulation of the endoplasmic reticulum stress pathway.

  7. Beta Blockers Suppress Dextrose-Induced Endoplasmic Reticulum Stress, Oxidative Stress, and Apoptosis in Human Coronary Artery Endothelial Cells.

    Science.gov (United States)

    Haas, Michael J; Kurban, William; Shah, Harshit; Onstead-Haas, Luisa; Mooradian, Arshag D

    Beta blockers are known to have favorable effects on endothelial function partly because of their capacity to reduce oxidative stress. To determine whether beta blockers can also prevent dextrose-induced endoplasmic reticulum (ER) stress in addition to their antioxidative effects, human coronary artery endothelial cells and hepatocyte-derived HepG2 cells were treated with 27.5 mM dextrose for 24 hours in the presence of carvedilol (a lipophilic beta blockers with alpha blocking activity), propranolol (a lipophilic nonselective beta blockers), and atenolol (a water-soluble selective beta blockers), and ER stress, oxidative, stress and cell death were measured. ER stress was measured using the placental alkaline phosphatase assay and Western blot analysis of glucose regulated protein 78, c-Jun-N-terminal kinase (JNK), phospho-JNK, eukaryotic initiating factor 2α (eIF2α), and phospho-eIF2α and measurement of X-box binding protein 1 (XBP1) mRNA splicing using reverse transcriptase-polymerase chain reaction. Superoxide (SO) generation was measured using the superoxide-reactive probe 2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo[1,2-A]pyrazin-3-one hydrochloride (MCLA) chemiluminescence. Cell viability was measured by propidium iodide staining method. The ER stress, SO production, and cell death induced by 27.5 mM dextrose were inhibited by all 3 beta blockers tested. The antioxidative and ER stress reducing effects of beta blockers were also observed in HepG2 cells. The salutary effects of beta blockers on endothelial cells in reducing both ER stress and oxidative stress may contribute to the cardioprotective effects of these agents.

  8. Thin Silicon MEMS Contact-Stress Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Kotovsky, J; Tooker, A; Horsley, D

    2010-03-22

    This thin, MEMS contact-stress (CS) sensor continuously and accurately measures time-varying, solid interface loads in embedded systems over tens of thousands of load cycles. Unlike all other interface load sensors, the CS sensor is extremely thin (< 150 {micro}m), provides accurate, high-speed measurements, and exhibits good stability over time with no loss of calibration with load cycling. The silicon CS sensor, 5 mm{sup 2} and 65 {micro}m thick, has piezoresistive traces doped within a load-sensitive diaphragm. The novel package utilizes several layers of flexible polyimide to mechanically and electrically isolate the sensor from the environment, transmit normal applied loads to the diaphragm, and maintain uniform thickness. The CS sensors have a highly linear output in the load range tested (0-2.4 MPa) with an average accuracy of {+-} 1.5%.

  9. The SAT Protein of Porcine Parvovirus Accelerates Viral Spreading through Induction of Irreversible Endoplasmic Reticulum Stress.

    Science.gov (United States)

    Mészáros, István; Tóth, Renáta; Olasz, Ferenc; Tijssen, Peter; Zádori, Zoltán

    2017-08-15

    The SAT protein (SATp) of porcine parvovirus (PPV) accumulates in the endoplasmic reticulum (ER), and SAT deletion induces the slow-spreading phenotype. The in vitro comparison of the wild-type Kresse strain and its SAT knockout (SAT(-)) mutant revealed that prolonged cell integrity and late viral release are responsible for the slower spreading of the SAT(-) virus. During PPV infection, regardless of the presence or absence of SATp, the expression of downstream ER stress response proteins (Xbp1 and CHOP) was induced. However, in the absence of SATp, significant differences in the quantity and the localization of CHOP were detected, suggesting a role of SATp in the induction of irreversible ER stress in infected cells. The involvement of the induction of irreversible ER stress in porcine testis (PT) cell necrosis and viral egress was confirmed by treatment of infected cells by ER stress-inducing chemicals (MG132, dithiothreitol, and thapsigargin), which accelerated the egress and spreading of both the wild-type and the SAT(-) viruses. UV stress induction had no beneficial effect on PPV infection, underscoring the specificity of ER stress pathways in the process. However, induction of CHOP and its nuclear translocation cannot alone be responsible for the biological effect of SAT, since nuclear CHOP could not complement the lack of SAT in a coexpression experiment.IMPORTANCE SATp is encoded by an alternative open reading frame of the PPV genome. Earlier we showed that SATp of the attenuated PPV NADL-2 strain accumulates in the ER and accelerates virus release and spreading. Our present work revealed that slow spreading is a general feature of SAT(-) PPVs and is the consequence of prolonged cell integrity. PPV infection induced ER stress in infected cells regardless of the presence of SATp, as demonstrated by the morphological changes of the ER and expression of the stress response proteins Xbp1 and CHOP. However, the presence of SATp made the ER stress more severe

  10. Z α-1 antitrypsin deficiency and the endoplasmic reticulum stress response.

    LENUS (Irish Health Repository)

    Greene, Catherine M

    2010-10-06

    The serine proteinase inhibitor α-1 antitrypsin (AAT) is produced principally by the liver at the rate of 2 g\\/d. It is secreted into the circulation and provides an antiprotease protective screen throughout the body but most importantly in the lung, where it can neutralise the activity of the serine protease neutrophil elastase. Mutations leading to deficiency in AAT are associated with liver and lung disease. The most notable is the Z AAT mutation, which encodes a misfolded variant of the AAT protein in which the glutamic acid at position 342 is replaced by a lysine. More than 95% of all individuals with AAT deficiency carry at least one Z allele. ZAAT protein is not secreted effectively and accumulates intracellularly in the endoplasmic reticulum (ER) of hepatocytes and other AAT-producing cells. This results in a loss of function associated with decreased circulating and intrapulmonary levels of AAT. However, the misfolded protein acquires a toxic gain of function that impacts on the ER. A major function of the ER is to ensure correct protein folding. ZAAT interferes with this function and promotes ER stress responses and inflammation. Here the signalling pathways activated during ER stress in response to accumulation of ZAAT are described and therapeutic strategies that can potentially relieve ER stress are discussed.

  11. Erlotinib promotes endoplasmic reticulum stress-mediated injury in the intestinal epithelium

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Lu; Hu, Lingna; Yang, Baofang; Fang, Xianying; Gao, Zhe; Li, Wanshuai; Sun, Yang; Shen, Yan; Wu, Xuefeng [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 22 Hankou Road, Nanjing 210093 (China); Shu, Yongqian [Department of Clinical Oncology, The First Affiliated Hospital of Nanjing Medical University, 140 Hanzhong Road, Nanjing 210029 (China); Gu, Yanhong, E-mail: guluer@163.com [Department of Clinical Oncology, The First Affiliated Hospital of Nanjing Medical University, 140 Hanzhong Road, Nanjing 210029 (China); Wu, Xudong, E-mail: xudongwu@nju.edu.cn [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 22 Hankou Road, Nanjing 210093 (China); Xu, Qiang, E-mail: molpharm@163.com [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)

    2014-07-01

    Erlotinib, a popular drug for treating non-small cell lung cancer (NSCLC), causes diarrhea in approximately 55% of patients receiving this drug. In the present study, we found that erlotinib induced barrier dysfunction in rat small intestine epithelial cells (IEC-6) by increasing epithelial permeability and down-regulating E-cadherin. The mRNA levels of various pro-inflammatory cytokines (Il-6, Il-25 and Il-17f) were increased after erlotinib treatment in IEC-6 cells. Erlotinib concentration- and time-dependently induced apoptosis and endoplasmic reticulum (ER) stress in both IEC-6 and human colon epithelial cells (CCD 841 CoN). Intestinal epithelial injury was also observed in male C57BL/6J mice administrated with erlotinib. Knockdown of C/EBP homologous protein (CHOP) with small interference RNA partially reversed erlotinib-induced apoptosis, production of IL-6 and down-regulation of E-cadherin in cultured intestinal epithelial cells. In conclusion, erlotinib caused ER stress-mediated injury in the intestinal epithelium, contributing to its side effects of diarrhea in patients. - Highlights: • Erlotinib destroyed barrier integrity both in vitro and in vivo. • Erlotinib induced inflammation both in vitro and in vivo. • Erlotinib induced apoptosis both in vitro and in vivo. • ER stress contributed to erlotinib-induced barrier dysfunction.

  12. Patulin induces apoptosis through ROS-mediated endoplasmic reticulum stress pathway.

    Science.gov (United States)

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

    2015-04-01

    Patulin (PAT) is a toxic metabolite produced by several filamentous fungi of the genera of Penicillium, Aspergillus, and Byssochlamys. PAT is the most common mycotoxin found in apples and apple-based products including juice, compotes, cider, and baby food. Exposure to this mycotoxin has been reported to induce intestinal and kidney injuries. This study investigated the mechanism of PAT-induced toxicity in human colon carcinoma (HCT116) and embryonic kidney cells (HEK293). We demonstrated that PAT activated endoplasmic reticulum (ER) and unfolded protein response as evidenced by up-regulation of GRP78 and GADD34, splicing of XBP1 mRNA, and expression of the proapoptotic factor CHOP. This ER stress response was accompanied by the induction of the mitochondrial apoptotic pathway. Apoptosis occurred with ROS production, drop in mitochondrial membrane potential and caspase activation. Further, we showed that deficiency of the proapoptotic protein Bax or Bak protected cells against PAT-induced apoptosis. The treatment of cells with the ROS scavenger N-acetyl cysteine inhibits the ER stress response and prevents mitochondrial apoptosis. Collectively, our data provide new mechanistic insights in the signaling pathways of the cell death induced by PAT and demonstrate that PAT induces cytotoxicity through a ROS-dependent mechanism involving ER stress and activation of mitochondrial apoptotic pathway in human intestinal and kidney cells. © The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology.All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  13. Endoplasmic reticulum stress in amelogenesis imperfecta and phenotypic rescue using 4-phenylbutyrate.

    Science.gov (United States)

    Brookes, Steven J; Barron, Martin J; Boot-Handford, Ray; Kirkham, Jennifer; Dixon, Michael J

    2014-05-01

    Inherited diseases caused by genetic mutations can arise due to loss of protein function. Alternatively, mutated proteins may mis-fold, impairing endoplasmic reticulum (ER) trafficking, causing ER stress and triggering the unfolded protein response (UPR). The UPR attempts to restore proteostasis but if unsuccessful drives affected cells towards apoptosis. Previously, we reported that in mice, the p.Tyr64His mutation in the enamel extracellular matrix (EEM) protein amelogenin disrupts the secretory pathway in the enamel-forming ameloblasts, resulting in eruption of malformed tooth enamel that phenocopies human amelogenesis imperfecta (AI). Defective amelogenin post-secretory self-assembly and processing within the developing EEM has been suggested to underlie the pathogenesis of X chromosome-linked AI. Here, we challenge this concept by showing that AI pathogenesis associated with the p.Tyr64His amelogenin mutation involves ameloblast apoptosis induced by ER stress. Furthermore, we show that 4-phenylbutyrate can rescue the enamel phenotype in affected female mice by promoting cell survival over apoptosis such that they are able to complete enamel formation despite the presence of the mutation, offering a potential therapeutic option for patients with this form of AI and emphasizing the importance of ER stress in the pathogenesis of this inherited conformational disease.

  14. Selenoprotein S/SEPS1 modifies endoplasmic reticulum stress in Z variant alpha1-antitrypsin deficiency.

    LENUS (Irish Health Repository)

    Kelly, Emer

    2009-06-19

    Z alpha(1)-antitrypsin (ZAAT) deficiency is a disease associated with emphysematous lung disease and also with liver disease. The liver disease of AAT deficiency is associated with endoplasmic reticulum (ER) stress. SEPS1 is a selenoprotein that, through a chaperone activity, decreases ER stress. To determine the effect of SEPS1 on ER stress in ZAAT deficiency, we measured activity of the grp78 promoter and levels of active ATF6 as markers of the unfolded protein response in HepG2 cells transfected with the mutant form of AAT, a ZAAT transgene. We evaluated levels of NFkappaB activity as a marker of the ER overload response. To determine the effect of selenium supplementation on the function of SEPS1, we investigated glutathione peroxidase activity, grp78 promoter activity, and NFkappaB activity in the presence or absence of selenium. SEPS1 reduced levels of active ATF6. Overexpression of SEPS1 also inhibited grp78 promoter and NFkappaB activity, and this effect was enhanced in the presence of selenium supplementation. This finding demonstrates a role for SEPS1 in ZAAT deficiency and suggests a possible therapeutic potential for selenium supplementation.

  15. Endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) in plants.

    Science.gov (United States)

    Wan, Shucen; Jiang, Liwen

    2016-05-01

    Being a major factory for protein synthesis, assembly, and export, the endoplasmic reticulum (ER) has a precise and robust ER quality control (ERQC) system monitoring its product line. However, when organisms are subjected to environmental stress, whether biotic or abiotic, the levels of misfolded proteins may overwhelm the ERQC system, tilting the balance between the capacity of and demand for ER quality control and resulting in a scenario termed ER stress. Intense or prolonged ER stress may cause damage to the ER as well as to other organelles, or even lead to cell death in extreme cases. To avoid such serious consequences, cells activate self-rescue programs to restore protein homeostasis in the ER, either through the enhancement of protein-folding and degradation competence or by alleviating the demands for such reactions. These are collectively called the unfolded protein response (UPR). Long investigated in mammalian cells and yeasts, the UPR is also of great interest to plant scientists. Among the three branches of UPR discovered in mammals, two have been studied in plants with plant homologs existing of the ER-membrane-associated activating transcription factor 6 (ATF6) and inositol-requiring enzyme 1 (IRE1). This review discusses the molecular mechanisms of these two types of UPR in plants, as well as the consequences of insufficient UPR, with a focus on experiments using model plants.

  16. Morphine Protects Spinal Cord Astrocytes from Glutamate-Induced Apoptosis via Reducing Endoplasmic Reticulum Stress

    Directory of Open Access Journals (Sweden)

    Chao Zhang

    2016-10-01

    Full Text Available Glutamate is not only a neurotransmitter but also an important neurotoxin in central nervous system (CNS. Chronic elevation of glutamate induces both neuronal and glial cell apoptosis. However, its effect on astrocytes is complex and still remains unclear. In this study, we investigated whether morphine, a common opioid ligand, could affect glutamate-induced apoptosis in astrocytes. Primary cultured astrocytes were incubated with glutamate in the presence/absence of morphine. It was found that morphine could reduce glutamate-induced apoptosis of astrocytes. Furthermore, glutamate activated Ca2+ release, thereby inducing endoplasmic reticulum (ER stress in astrocytes, while morphine attenuated this deleterious effect. Using siRNA to reduce the expression of κ-opioid receptor, morphine could not effectively inhibit glutamate-stimulated Ca2+ release in astrocytes, the protective effect of morphine on glutamate-injured astrocytes was also suppressed. These results suggested that morphine could protect astrocytes from glutamate-induced apoptosis via reducing Ca2+ overload and ER stress pathways. In conclusion, this study indicated that excitotoxicity participated in the glutamate mediated apoptosis in astrocytes, while morphine attenuated this deleterious effect via regulating Ca2+ release and ER stress.

  17. Trichodermin induces cell apoptosis through mitochondrial dysfunction and endoplasmic reticulum stress in human chondrosarcoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Su, Chen-Ming [Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan (China); Wang, Shih-Wei [Department of Medicine, Mackay Medical College, New Taipei City, Taiwan (China); Lee, Tzong-Huei [Graduate Institute of Pharmacognosy, Taipei Medical University, Taipei, Taiwan (China); Tzeng, Wen-Pei [Graduate Institute of Sports and Health, National Changhua University of Education, Changhua, Taiwan (China); Hsiao, Che-Jen [School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Liu, Shih-Chia [Department of Orthopaedics, Mackay Memorial Hospital, Taipei, Taiwan (China); Tang, Chih-Hsin, E-mail: chtang@mail.cmu.edu.tw [Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan (China); Department of Pharmacology, School of Medicine, China Medical University, Taichung, Taiwan (China); Department of Biotechnology, College of Health Science, Asia University, Taichung, Taiwan (China)

    2013-10-15

    Chondrosarcoma is the second most common primary bone tumor, and it responds poorly to both chemotherapy and radiation treatment. Nalanthamala psidii was described originally as Myxosporium in 1926. This is the first study to investigate the anti-tumor activity of trichodermin (trichothec-9-en-4-ol, 12,13-epoxy-, acetate), an endophytic fungal metabolite from N. psidii against human chondrosarcoma cells. We demonstrated that trichodermin induced cell apoptosis in human chondrosarcoma cell lines (JJ012 and SW1353 cells) instead of primary chondrocytes. In addition, trichodermin triggered endoplasmic reticulum (ER) stress protein levels of IRE1, p-PERK, GRP78, and GRP94, which were characterized by changes in cytosolic calcium levels. Furthermore, trichodermin induced the upregulation of Bax and Bid, the downregulation of Bcl-2, and the dysfunction of mitochondria, which released cytochrome c and activated caspase-3 in human chondrosarcoma. In addition, animal experiments illustrated reduced tumor volume, which led to an increased number of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive cells and an increased level of cleaved PARP protein following trichodermin treatment. Together, this study demonstrates that trichodermin is a novel anti-tumor agent against human chondrosarcoma cells both in vitro and in vivo via mitochondrial dysfunction and ER stress. - Highlights: • Trichodermin induces chondrosarcoma apoptosis. • ER stress is involved in trichodermin-induced cell death. • Trichodermin induces chondrosarcoma death in vivo.

  18. Chaperone-Targeting Cytotoxin and Endoplasmic Reticulum Stress-Inducing Drug Synergize to Kill Cancer Cells

    Directory of Open Access Journals (Sweden)

    Joseph M. Backer

    2009-11-01

    Full Text Available Diverse physiological and therapeutic insults that increase the amount of unfolded or misfolded proteins in the endoplasmic reticulum (ER induce the unfolded protein response, an evolutionarily conserved protective mechanism that manages ER stress. Glucose-regulated protein 78/immunoglobulin heavy-chain binding protein (GRP78/BiP is an ER-resident protein that plays a central role in the ER stress response and is the only known substrate of the proteolytic A subunit (SubA of a novel bacterial AB5 toxin. Here, we report that an engineered fusion protein, epidermal growth factor (EGF-SubA, combining EGF and SubA, is highly toxic to growing and confluent epidermal growth factor receptor-expressing cancer cells, and its cytotoxicity is mediated by a remarkably rapid cleavage of GRP78/BiP. Systemic delivery of EGF-SubA results in a significant inhibition of human breast and prostate tumor xenografts in mouse models. Furthermore, EGF-SubA dramatically increases the sensitivity of cancer cells to the ER stress-inducing drug thapsigargin, and vice versa, demonstrating the first example of mechanism-based synergism in the action of a cytotoxin and an ER-targeting drug.

  19. Emergence of endoplasmic reticulum stress and activated microglia in Purkinje cell degeneration mice.

    Science.gov (United States)

    Kyuhou, Shin-ichi; Kato, Nobuo; Gemba, Hisae

    2006-03-27

    In the current studies, we characterized the molecular and cellular mechanism of cell death in Purkinje cell degeneration (pcd) mice using real-time quantitative PCR, immunohistochemistry, and Western blotting. It appears that endoplasmic reticulum (ER) stress is involved in this degeneration of Purkinje cells because ER stress-related substrates, such as CHOP and caspase 12, were strongly activated in Purkinje cells of pcd mice during the third postnatal (P) week. A significant increase in the expression of the ER-specific chaperone BiP suggested that unfolded protein responses were induced. We also found that Purkinje cells underwent apoptosis via the activation of caspase 3 and subsequent fragmentation of DNA. In addition to the activation of apoptosis in Purkinje cells, many activated microglial cells are found to be present in the molecular layer of the cerebellar cortex. In the later phase of degeneration, there was conspicuous expression of inducible nitric oxide synthase (iNOS), and some Purkinje cells were strongly labeled with an antibody to nitrotyrosine, suggesting that Purkinje cells in pcd mice are damaged by nitric oxide released from microglial cells. Administration of minocycline, which may inhibit iNOS expression, delayed the death of Purkinje cells in pcd mice and mildly improved their motor abilities. These findings suggest that ER stress participates in the degeneration of Purkinje cells and that activation of microglia accelerates Purkinje cell death in pcd mice.

  20. Regulation of mitochondrial function and endoplasmic reticulum stress by nitric oxide in pluripotent stem cells

    Science.gov (United States)

    Caballano-Infantes, Estefania; Terron-Bautista, José; Beltrán-Povea, Amparo; Cahuana, Gladys M; Soria, Bernat; Nabil, Hajji; Bedoya, Francisco J; Tejedo, Juan R

    2017-01-01

    Mitochondrial dysfunction and endoplasmic reticulum stress (ERS) are global processes that are interrelated and regulated by several stress factors. Nitric oxide (NO) is a multifunctional biomolecule with many varieties of physiological and pathological functions, such as the regulation of cytochrome c inhibition and activation of the immune response, ERS and DNA damage; these actions are dose-dependent. It has been reported that in embryonic stem cells, NO has a dual role, controlling differentiation, survival and pluripotency, but the molecular mechanisms by which it modulates these functions are not yet known. Low levels of NO maintain pluripotency and induce mitochondrial biogenesis. It is well established that NO disrupts the mitochondrial respiratory chain and causes changes in mitochondrial Ca2+ flux that induce ERS. Thus, at high concentrations, NO becomes a potential differentiation agent due to the relationship between ERS and the unfolded protein response in many differentiated cell lines. Nevertheless, many studies have demonstrated the need for physiological levels of NO for a proper ERS response. In this review, we stress the importance of the relationships between NO levels, ERS and mitochondrial dysfunction that control stem cell fate as a new approach to possible cell therapy strategies. PMID:28289506

  1. Thin Silicon MEMS Contact-Stress Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Kotovsky, J; Tooker, A; Horsley, D A

    2009-12-07

    This work offers the first, thin, MEMS contact-stress (CS) sensor capable of accurate in situ measruement of time-varying, contact-stress between two solid interfaces (e.g. in vivo cartilage contact-stress and body armor dynamic loading). This CS sensor is a silicon-based device with a load sensitive diaphragm. The diaphragm is doped to create piezoresistors arranged in a full Wheatstone bridge. The sensor is similar in performance to established silicon pressure sensors, but it is reliably produced to a thickness of 65 {micro}m. Unlike commercial devices or other research efforts, this CS sensor, including packaging, is extremely thin (< 150 {micro}m fully packaged) so that it can be unobtrusively placed between contacting structures. It is built from elastic, well-characterized materials, providing accurate and high-speed (50+ kHz) measurements over a potential embedded lifetime of decades. This work explored sensor designs for an interface load range of 0-2 MPa; however, the CS sensor has a flexible design architecture to measure a wide variety of interface load ranges.

  2. Smoke Exposure Causes Endoplasmic Reticulum Stress and Lipid Accumulation in Retinal Pigment Epithelium through Oxidative Stress and Complement Activation*

    Science.gov (United States)

    Kunchithapautham, Kannan; Atkinson, Carl; Rohrer, Bärbel

    2014-01-01

    Age-related macular degeneration (AMD) is a complex disease caused by genetic and environmental factors, including genetic variants in complement components and smoking. Smoke exposure leads to oxidative stress, complement activation, endoplasmic reticulum (ER) stress, and lipid dysregulation, which have all been proposed to be associated with AMD pathogenesis. Here we examine the effects of smoke exposure on the retinal pigment epithelium (RPE). Mice were exposed to cigarette smoke or filtered air for 6 months. RPE cells grown as stable monolayers were exposed to 5% cigarette smoke extract (CSE). Effects of smoke were determined by biochemical, molecular, and histological measures. Effects of the alternative pathway (AP) of complement and complement C3a anaphylatoxin receptor signaling were analyzed using knock-out mice or specific inhibitors. ER stress markers were elevated after smoke exposure in RPE of intact mice, which was eliminated in AP-deficient mice. To examine this relationship further, RPE monolayers were exposed to CSE. Short term smoke exposure resulted in production and release of complement C3, the generation of C3a, oxidative stress, complement activation on the cell membrane, and ER stress. Long term exposure to CSE resulted in lipid accumulation, and secretion. All measures were reversed by blocking C3a complement receptor (C3aR), alternative complement pathway signaling, and antioxidant therapy. Taken together, our results provide clear evidence that smoke exposure results in oxidative stress and complement activation via the AP, resulting in ER stress-mediated lipid accumulation, and further suggesting that oxidative stress and complement act synergistically in the pathogenesis of AMD. PMID:24711457

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

    Science.gov (United States)

    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.

  4. IRES-dependent translational control during virus-induced endoplasmic reticulum stress and apoptosis

    Directory of Open Access Journals (Sweden)

    Paul eHanson

    2012-03-01

    Full Text Available Many virus infections and stresses can induce endoplasmic reticulum (ER stress response, a host self defense mechanism against viral invasion and stress. During this event, viral and cellular gene expression is actively regulated and often encounters a switching of the translation initiation from cap-dependent to IRES (internal ribosome entry sites-dependent. This switching is largely dependent on the mRNA structure of the 5’untranslated region (5’UTR and on the particular stress stimuli. Picornviruses and some other viruses contain an IRES within their 5’UTR of viral genome and employ an IRES-driven mechanism for translation initiation. Recently, a growing number of cellular genes involved in growth control, cell cycle progression and apoptosis were also found to contain one or more IRES within their long highly structured 5’UTRs. These genes initiate translation usually by a cap-dependent mechanism under normal physiological conditions; however, in certain environments, such as infection, starvation and heat shock they shift translation initiation to an IRES-dependent modality. Although the molecular mechanism is not entirely understood, a number of studies have revealed that several cellular biochemical processes are responsible for the switching of translation initiation to IRES-dependent. These include the cleavage of translation initiation factors by viral and/or host proteases, phosphorylation (inactivation of host factors for translation initiation, over-production of homologous proteins of cap-binding protein eIF4E, suppression of cap-binding protein eIF4E expression by specific microRNA, activation of enzymes for mRNA decapping, as well as others. Here, we summarize the recent advances in our understanding of the molecular mechanisms for the switching of translation initiation, particularly for the proteins involved in cell survival and apoptosis in the ER stress pathways during viral infections.

  5. Apolipoprotein E4 impairs macrophage efferocytosis and potentiates apoptosis by accelerating endoplasmic reticulum stress.

    Science.gov (United States)

    Cash, James G; Kuhel, David G; Basford, Joshua E; Jaeschke, Anja; Chatterjee, Tapan K; Weintraub, Neal L; Hui, David Y

    2012-08-10

    Apolipoprotein (apo) E4 is a major genetic risk factor for a wide spectrum of inflammatory metabolic diseases, including atherosclerosis, diabetes, and Alzheimer disease. This study compared diet-induced adipose tissue inflammation as well as functional properties of macrophages isolated from human APOE3 and APOE4 mice to identify the mechanism responsible for the association between apoE4 and inflammatory metabolic diseases. The initial study confirmed previous reports that APOE4 gene replacement mice were less sensitive than APOE3 mice to diet-induced body weight gain but exhibited hyperinsulinemia, and their adipose tissues were similarly inflamed as those in APOE3 mice. Peritoneal macrophages isolated from APOE4 mice were defective in efferocytosis compared with APOE3 macrophages. Increased cell death was also observed in APOE4 macrophages when stimulated with LPS or oxidized LDL. Western blot analysis of cell lysates revealed that APOE4 macrophages displayed elevated JNK phosphorylation indicative of cell stress even under basal culturing conditions. Significantly higher cell stress due mainly to potentiation of endoplasmic reticulum (ER) stress signaling was also observed in APOE4 macrophages after LPS and oxidized LDL activation. The defect in efferocytosis and elevated apoptosis sensitivity of APOE4 macrophages was ameliorated by treatment with the ER chaperone tauroursodeoxycholic acid. Taken together, these results showed that apoE4 expression causes macrophage dysfunction and promotes apoptosis via ER stress induction. The reduction of ER stress in macrophages may be a viable option to reduce inflammation and inflammation-related metabolic disorders associated with the apoE4 polymorphism.

  6. The role of endoplasmic reticulum stress in endothelial dysfunction induced by homocysteine thiolactone.

    Science.gov (United States)

    Wu, Shujin; Gao, Xiang; Yang, Shehua; Meng, Min; Yang, Xiaolai; Ge, Bin

    2015-06-01

    Our and other studies have reported that homocysteine thiolactone (HTL) could induce endothelial dysfunction. However, the precise mechanism was largely unknown. In this study, we tested the most possible factor-endoplasmic reticulum (ER) stress, which was demonstrated to be involved in endothelial dysfunction in cardiovascular disease. Acetylcholine (Ach)-induced endothelium-dependent relaxation (EDR) and biochemical parameters were measured in rat isolated aorta. The level of reactive oxygen species (ROS) and NO was designed by specific fluorescent probe DCFH-DA and DAF-FM DA separately. The nuclear translocation of the NF-κB was studied by immune-fluorescence. The mRNA expression and protein expression of GRP78--a key indicator for the induction of ER stress--were assessed by real-time PCR and Western blot. Two ER stress inhibitors-4-PBA (5 mm) and Tudca (500 μg/mL)--significantly prevented HTL-impaired EDR and increased NO release, endothelial nitric oxide synthase (eNOS) and SOD activity, decreased ROS production, NADPH activity, NOX-4 mRNA and MDA level. We also found that 4-PBA and Tudca blocked HTL--induced NF-κB activation thus inhibiting the downstream target gene production including TNF-α and ICAM-1. Simultaneously, HTL increased the mRNA and protein level of GRP78. HTL could induce ER stress leading to a downstream enhancement of oxidative stress and inflammation, which finally caused vascular endothelial dysfunction. © 2015 Société Française de Pharmacologie et de Thérapeutique.

  7. Sulindac sulfide inhibits sarcoendoplasmic reticulum Ca2+ ATPase, induces endoplasmic reticulum stress response, and exerts toxicity in glioma cells: relevant similarities to and important differences from celecoxib.

    Science.gov (United States)

    White, M C; Johnson, G G; Zhang, W; Hobrath, J V; Piazza, G A; Grimaldi, M

    2013-03-01

    Malignant gliomas have low survival expectations regardless of current treatments. Nonsteroidal anti-inflammatory drugs (NSAIDs) prevent cell transformation and slow cancer cell growth by mechanisms independent of cyclooxygenase (COX) inhibition. Certain NSAIDs trigger the endoplasmic reticulum stress response (ERSR), as revealed by upregulation of molecular chaperones such as GRP78 and C/EBP homologous protein (CHOP). Although celecoxib (CELE) inhibits the sarcoendoplasmic reticulum Ca(2+) ATPase (SERCA), an effect known to induce ERSR, sulindac sulfide (SS) has not been reported to affect SERCA. Here, we investigated these two drugs for their effects on Ca(2+) homeostasis, ERSR, and glioma cell survival. Our findings indicate that SS is a reversible inhibitor of SERCA and that both SS and CELE bind SERCA at its cyclopiazonic acid binding site. Furthermore, CELE releases additional Ca(2+) from the mitochondria. In glioma cells, both NSAIDS upregulate GRP78 and activate ER-associated caspase-4 and caspase-3. Although only CELE upregulates the expression of CHOP, it appears that CHOP induction could be associated with mitochondrial poisoning. In addition, CHOP induction appears to be uncorrelated with the gliotoxicity of these NSAIDS in our experiments. Our data suggest that activation of ERSR is primarily responsible for the gliotoxic effect of these NSAIDS. Because SS has good brain bioavailability, has lower COX-2 inhibition, and has no mitochondrial effects, it represents a more appealing molecular candidate than CELE to achieve gliotoxicity via activation of ERSR.

  8. Effective Components of Panax quinquefolius and Corydalis tuber Protect Myocardium through Attenuating Oxidative Stress and Endoplasmic Reticulum Stress

    Directory of Open Access Journals (Sweden)

    Mei Xue

    2013-01-01

    Full Text Available Both oxidative stress and endoplasmic reticulum stress (ERS have been implicated in carcinogenesis and neurological diseases, while there are few reports about the mechanisms of them in the progression of acute myocardial infarction (AMI. This study examined oxidative stress and ERS in a rat model of AMI and evaluated their role in therapy by metoprolol and effective components of Panax quinquefolius and Corydalis tuber (EPC. In the present study a rat model of AMI was established by ligation of the left anterior descending coronary artery. After oral administration of metoprolol or low-to-high doses of EPC for 2 weeks, serum malondialdehyde (MDA, superoxide dismutase (SOD, and 8-iso-prostaglandin F2α (8-iso-PGF2α were detected using enzyme-linked immunosorbent assay (ELISA. Quantitative real-time PCR and Western blotting were used to examine mRNA and protein expressions of the hallmarks of ERS-glucose-regulated protein-78 (GRP78 and CCAAT/enhancer-binding protein homologous protein (CHOP. We confirmed that both metoprolol and moderate-to-high dose of EPC decreased 8-iso-PGF2α serum level and downregulated the mRNA and protein expressions of GRP78 and CHOP in myocardium, while EPC also increased SOD serum level. These results indicated that metoprolol and EPC protect the myocardium by attenuating oxidative stress and ERS induced by myocardial infarction, highlighting the ERS pathways as potential therapeutic targets for AMI.

  9. Mitochondrial and endoplasmic reticulum stress pathways cooperate in zearalenone-induced apoptosis of human leukemic cells

    Directory of Open Access Journals (Sweden)

    Chokchaichamnankit Daranee

    2010-12-01

    Full Text Available Abstract Background Zearalenone (ZEA is a phytoestrogen from Fusarium species. The aims of the study was to identify mode of human leukemic cell death induced by ZEA and the mechanisms involved. Methods Cell cytotoxicity of ZEA on human leukemic HL-60, U937 and peripheral blood mononuclear cells (PBMCs was performed by using 3-(4,5-dimethyl-2,5-diphenyl tetrazolium bromide (MTT assay. Reactive oxygen species production, cell cycle analysis and mitochondrial transmembrane potential reduction was determined by employing 2',7'-dichlorofluorescein diacetate, propidium iodide and 3,3'-dihexyloxacarbocyanine iodide and flow cytometry, respectively. Caspase-3 and -8 activities were detected by using fluorogenic Asp-Glu-Val-Asp-7-amino-4-methylcoumarin (DEVD-AMC and Ile-Glu-Thr-Asp-7-amino-4-methylcoumarin (IETD-AMC substrates, respectively. Protein expression of cytochrome c, Bax, Bcl-2 and Bcl-xL was performed by Western blot. The expression of proteins was assessed by two-dimensional polyacrylamide gel-electrophoresis (PAGE coupled with LC-MS2 analysis and real-time reverse transcription polymerase chain reaction (RT-PCR approach. Results ZEA was cytotoxic to U937 > HL-60 > PBMCs and caused subdiploid peaks and G1 arrest in both cell lines. Apoptosis of human leukemic HL-60 and U937 cell apoptosis induced by ZEA was via an activation of mitochondrial release of cytochrome c through mitochondrial transmembrane potential reduction, activation of caspase-3 and -8, production of reactive oxygen species and induction of endoplasmic reticulum stress. Bax was up regulated in a time-dependent manner and there was down regulation of Bcl-xL expression. Two-dimensional PAGE coupled with LC-MS2 analysis showed that ZEA treatment of HL-60 cells produced differences in the levels of 22 membrane proteins such as apoptosis inducing factor and the ER stress proteins including endoplasmic reticulum protein 29 (ERp29, 78 kDa glucose-regulated protein, heat shock

  10. Mitochondrial and endoplasmic reticulum stress pathways cooperate in zearalenone-induced apoptosis of human leukemic cells

    Science.gov (United States)

    2010-01-01

    Background Zearalenone (ZEA) is a phytoestrogen from Fusarium species. The aims of the study was to identify mode of human leukemic cell death induced by ZEA and the mechanisms involved. Methods Cell cytotoxicity of ZEA on human leukemic HL-60, U937 and peripheral blood mononuclear cells (PBMCs) was performed by using 3-(4,5-dimethyl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Reactive oxygen species production, cell cycle analysis and mitochondrial transmembrane potential reduction was determined by employing 2',7'-dichlorofluorescein diacetate, propidium iodide and 3,3'-dihexyloxacarbocyanine iodide and flow cytometry, respectively. Caspase-3 and -8 activities were detected by using fluorogenic Asp-Glu-Val-Asp-7-amino-4-methylcoumarin (DEVD-AMC) and Ile-Glu-Thr-Asp-7-amino-4-methylcoumarin (IETD-AMC) substrates, respectively. Protein expression of cytochrome c, Bax, Bcl-2 and Bcl-xL was performed by Western blot. The expression of proteins was assessed by two-dimensional polyacrylamide gel-electrophoresis (PAGE) coupled with LC-MS2 analysis and real-time reverse transcription polymerase chain reaction (RT-PCR) approach. Results ZEA was cytotoxic to U937 > HL-60 > PBMCs and caused subdiploid peaks and G1 arrest in both cell lines. Apoptosis of human leukemic HL-60 and U937 cell apoptosis induced by ZEA was via an activation of mitochondrial release of cytochrome c through mitochondrial transmembrane potential reduction, activation of caspase-3 and -8, production of reactive oxygen species and induction of endoplasmic reticulum stress. Bax was up regulated in a time-dependent manner and there was down regulation of Bcl-xL expression. Two-dimensional PAGE coupled with LC-MS2 analysis showed that ZEA treatment of HL-60 cells produced differences in the levels of 22 membrane proteins such as apoptosis inducing factor and the ER stress proteins including endoplasmic reticulum protein 29 (ERp29), 78 kDa glucose-regulated protein, heat shock protein 90 and

  11. KUS121, a VCP modulator, attenuates ischemic retinal cell death via suppressing endoplasmic reticulum stress

    Science.gov (United States)

    Hata, Masayuki; Ikeda, Hanako O.; Kikkawa, Chinami; Iwai, Sachiko; Muraoka, Yuki; Hasegawa, Tomoko; Kakizuka, Akira; Yoshimura, Nagahisa

    2017-01-01

    Ischemic neural damages cause several devastating diseases, including brain stroke and ischemic retinopathies, and endoplasmic reticulum (ER) stress has been proposed to be the underlying mechanism of the neuronal cell death of these conditions. We previously synthesized Kyoto University substances (KUSs) as modulators of valosin-containing protein (VCP); KUSs inhibit VCP ATPase activity and protect cells from different cell death-inducing insults. Here, we examined the efficacy of KUS121 in a rat model of retinal ischemic injury. Systemic administration of KUS121 to rats with ischemic retinal injury significantly suppressed inner retinal thinning and death of retinal ganglion and amacrine cells, with a significant functional maintenance of visual functions, as judged by electroretinography. Furthermore, intravitreal injection of KUS121, which is the clinically preferred route of drug administration for retinal diseases, appeared to show an equal or better neuroprotective efficacy in the ischemic retina compared with systemic administration. Indeed, induction of the ER stress marker C/EBP homologous protein (CHOP) after the ischemic insult was significantly suppressed by KUS121 administration. Our study suggests VCP modulation by KUS as a promising novel therapeutic strategy for ischemic neuronal diseases. PMID:28317920

  12. Altered Ca2+ Homeostasis and Endoplasmic Reticulum Stress in Myotonic Dystrophy Type 1 Muscle Cells

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    Gyorgy Szabadkai

    2013-06-01

    Full Text Available The pathogenesis of Myotonic Dystrophy type 1 (DM1 is linked to unstable CTG repeats in the DMPK gene which induce the mis-splicing to fetal/neonatal isoforms of many transcripts, including those involved in cellular Ca2+ homeostasis. Here we monitored the splicing of three genes encoding for Ca2+ transporters and channels (RyR1, SERCA1 and CACN1S during maturation of primary DM1 muscle cells in parallel with the functionality of the Excitation-Contraction (EC coupling machinery. At 15 days of differentiation, fetal isoforms of SERCA1 and CACN1S mRNA were significantly higher in DM1 myotubes compared to controls. Parallel functional studies showed that the cytosolic Ca2+ response to depolarization in DM1 myotubes did not increase during the progression of differentiation, in contrast to control myotubes. While we observed no differences in the size of intracellular Ca2+ stores, DM1 myotubes showed significantly reduced RyR1 protein levels, uncoupling between the segregated ER/SR Ca2+ store and the voltage-induced Ca2+ release machinery, parallel with induction of endoplasmic reticulum (ER stress markers. In conclusion, our data suggest that perturbed Ca2+ homeostasis, via activation of ER stress, contributes to muscle degeneration in DM1 muscle cells likely representing a premature senescence phenotype.

  13. Intracellular Accumulation of Gold Nanoparticles Leads to Inhibition of Macropinocytosis to Reduce the Endoplasmic Reticulum Stress

    Science.gov (United States)

    Gunduz, Nuray; Ceylan, Hakan; Guler, Mustafa O.; Tekinay, Ayse B.

    2017-01-01

    Understanding the toxicity of nanomaterials remains largely limited to acute cellular response, i.e., short-term in vitro cell-death based assays, and analyses of tissue- and organ-level accumulation and clearance patterns in animal models, which have produced very little information about how these materials (from the toxicity point of view) interact with the complex intracellular machinery. In particular, understanding the mechanism of toxicity caused by the gradual accumulation of nanomaterials due to prolonged exposure times is essential yet still continue to be a largely unexplored territory. Herein, we show intracellular accumulation and the associated toxicity of gold nanoparticles (AuNPs) for over two-months in the cultured vascular endothelial cells. We observed that steady exposure of AuNPs at low (non-lethal) dose leads to rapid intracellular accumulation without causing any detectable cell death while resulting in elevated endoplasmic reticulum (ER) stress. Above a certain intracellular AuNP threshold, inhibition of macropinocytosis mechanism ceases further nanoparticle uptake. Interestingly, the intracellular depletion of nanoparticles is irreversible. Once reaching the maximum achievable intracellular dose, a steady depletion is observed, while no cell death is observed at any stage of this overall process. This depletion is important for reducing the ER stress. To our knowledge, this is the first report suggesting active regulation of nanoparticle uptake by cells and the impact of long-term exposure to nanoparticles in vitro. PMID:28145529

  14. Intracellular Accumulation of Gold Nanoparticles Leads to Inhibition of Macropinocytosis to Reduce the Endoplasmic Reticulum Stress

    Science.gov (United States)

    Gunduz, Nuray; Ceylan, Hakan; Guler, Mustafa O.; Tekinay, Ayse B.

    2017-02-01

    Understanding the toxicity of nanomaterials remains largely limited to acute cellular response, i.e., short-term in vitro cell-death based assays, and analyses of tissue- and organ-level accumulation and clearance patterns in animal models, which have produced very little information about how these materials (from the toxicity point of view) interact with the complex intracellular machinery. In particular, understanding the mechanism of toxicity caused by the gradual accumulation of nanomaterials due to prolonged exposure times is essential yet still continue to be a largely unexplored territory. Herein, we show intracellular accumulation and the associated toxicity of gold nanoparticles (AuNPs) for over two-months in the cultured vascular endothelial cells. We observed that steady exposure of AuNPs at low (non-lethal) dose leads to rapid intracellular accumulation without causing any detectable cell death while resulting in elevated endoplasmic reticulum (ER) stress. Above a certain intracellular AuNP threshold, inhibition of macropinocytosis mechanism ceases further nanoparticle uptake. Interestingly, the intracellular depletion of nanoparticles is irreversible. Once reaching the maximum achievable intracellular dose, a steady depletion is observed, while no cell death is observed at any stage of this overall process. This depletion is important for reducing the ER stress. To our knowledge, this is the first report suggesting active regulation of nanoparticle uptake by cells and the impact of long-term exposure to nanoparticles in vitro.

  15. ATF6 as a Transcription Activator of the Endoplasmic Reticulum Stress Element: Thapsigargin Stress-Induced Changes and Synergistic Interactions with NF-Y and YY1

    OpenAIRE

    Li, Mingqing; Baumeister, Peter; Roy, Binayak; Phan, Trevor; Foti, Dolly; Luo, Shengzhan; Lee, Amy S.

    2000-01-01

    ATF6, a member of the leucine zipper protein family, can constitutively induce the promoter of glucose-regulated protein (grp) genes through activation of the endoplasmic reticulum (ER) stress element (ERSE). To understand the mechanism of grp78 induction by ATF6 in cells subjected to ER calcium depletion stress mediated by thapsigargin (Tg) treatment, we discovered that ATF6 itself undergoes Tg stress-induced changes. In nonstressed cells, ATF6, which contains a putative short transmembrane ...

  16. Selective modulation of endoplasmic reticulum stress markers in prostate cancer cells by a standardized mangosteen fruit extract.

    Science.gov (United States)

    Li, Gongbo; Petiwala, Sakina M; Pierce, Dana R; Nonn, Larisa; Johnson, Jeremy J

    2013-01-01

    The increased proliferation of cancer cells is directly dependent on the increased activity of the endoplasmic reticulum (ER) machinery which is responsible for protein folding, assembly, and transport. In fact, it is so critical that perturbations in the endoplasmic reticulum can lead to apoptosis. This carefully regulated organelle represents a unique target of cancer cells while sparing healthy cells. In this study, a standardized mangosteen fruit extract (MFE) was evaluated for modulating ER stress proteins in prostate cancer. Two human prostate cancer cell lines, 22Rv1 and LNCaP, and prostate epithelial cells (PrECs) procured from two patients undergoing radical prostatectomy were treated with MFE. Flow cytometry, MTT, BrdU and Western blot were used to evaluate cell apoptosis, viability, proliferation and ER stress. Next, we evaluated MFE for microsomal stability and anti-cancer activity in nude mice. MFE induced apoptosis, decreased viability and proliferation in prostate cancer cells. MFE increased the expression of ER stress proteins. Interestingly, MFE selectively promotes ER stress in prostate cancer cells while sparing PrECs. MFE suppressed tumor growth in a xenograft tumor model without obvious toxicity. Mangosteen fruit extract selectively promotes endoplasmic reticulum stress in cancer cells while sparing non-tumorigenic prostate epithelial cells. Furthermore, in an in vivo setting mangosteen fruit extract significantly reduces xenograft tumor formation.

  17. Selective modulation of endoplasmic reticulum stress markers in prostate cancer cells by a standardized mangosteen fruit extract.

    Directory of Open Access Journals (Sweden)

    Gongbo Li

    Full Text Available The increased proliferation of cancer cells is directly dependent on the increased activity of the endoplasmic reticulum (ER machinery which is responsible for protein folding, assembly, and transport. In fact, it is so critical that perturbations in the endoplasmic reticulum can lead to apoptosis. This carefully regulated organelle represents a unique target of cancer cells while sparing healthy cells. In this study, a standardized mangosteen fruit extract (MFE was evaluated for modulating ER stress proteins in prostate cancer. Two human prostate cancer cell lines, 22Rv1 and LNCaP, and prostate epithelial cells (PrECs procured from two patients undergoing radical prostatectomy were treated with MFE. Flow cytometry, MTT, BrdU and Western blot were used to evaluate cell apoptosis, viability, proliferation and ER stress. Next, we evaluated MFE for microsomal stability and anti-cancer activity in nude mice. MFE induced apoptosis, decreased viability and proliferation in prostate cancer cells. MFE increased the expression of ER stress proteins. Interestingly, MFE selectively promotes ER stress in prostate cancer cells while sparing PrECs. MFE suppressed tumor growth in a xenograft tumor model without obvious toxicity. Mangosteen fruit extract selectively promotes endoplasmic reticulum stress in cancer cells while sparing non-tumorigenic prostate epithelial cells. Furthermore, in an in vivo setting mangosteen fruit extract significantly reduces xenograft tumor formation.

  18. Prolonged endoplasmic reticulum stress alters placental morphology and causes low birth weight

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami, Takashige, E-mail: tkawakami@ph.bunri-u.ac.jp; Yoshimi, Masaki; Kadota, Yoshito; Inoue, Masahisa; Sato, Masao; Suzuki, Shinya

    2014-03-01

    The role of endoplasmic reticulum (ER) stress in pregnancy remains largely unknown. Pregnant mice were subcutaneously administered tunicamycin (Tun), an ER stressor, as a single dose [0, 50, and 100 μg Tun/kg/body weight (BW)] on gestation days (GDs) 8.5, 12.5, and 15.5. A high incidence (75%) of preterm delivery was observed only in the group treated with Tun 100 μg/kg BW at GD 15.5, indicating that pregnant mice during late gestation are more susceptible to ER stress on preterm delivery. We further examined whether prolonged in utero exposure to ER stress affects fetal development. Pregnant mice were subcutaneously administered a dose of 0, 20, 40, and 60 μg Tun/kg from GD 12.5 to 16.5. Tun treatment decreased the placental and fetal weights in a dose-dependent manner. Histological evaluation showed the formation of a cluster of spongiotrophoblast cells in the labyrinth zone of the placenta of Tun-treated mice. The glycogen content of the fetal liver and placenta from Tun-treated mice was lower than that from control mice. Tun treatment decreased mRNA expression of Slc2a1/glucose transporter 1 (GLUT1), which is a major transporter for glucose, but increased placental mRNA levels of Slc2a3/GLUT3. Moreover, maternal exposure to Tun resulted in a decrease in vascular endothelial growth factor receptor-1 (VEGFR-1), VEGFR-2, and placental growth factor. These results suggest that excessive and exogenous ER stress may induce functional abnormalities in the placenta, at least in part, with altered GLUT and vascular-related gene expression, resulting in low infant birth weight. - Highlights: • Maternal exposure to excessive ER stress induced preterm birth and IUGR. • Prolonged excessive ER stress altered the formation of the placental labyrinth. • ER stress decreased GLUT1 mRNA expression in the placenta, but increased GLUT3. • ER stress-induced IUGR causes decreased glycogen and altered glucose transport.

  19. A transgenic zebrafish model for monitoring xbp1 splicing and endoplasmic reticulum stress in vivo.

    Science.gov (United States)

    Li, Junling; Chen, Zhiliang; Gao, Lian-Yong; Colorni, Angelo; Ucko, Michal; Fang, Shengyun; Du, Shao Jun

    2015-08-01

    Accumulation of misfolded or unfolded proteins in the endoplasmic reticulum (ER) triggers ER stress that initiates unfolded protein response (UPR). XBP1 is a transcription factor that mediates one of the key signaling pathways of UPR to cope with ER stress through regulating gene expression. Activation of XBP1 involves an unconventional mRNA splicing catalyzed by IRE1 endonuclease that removes an internal 26 nucleotides from xbp1 mRNA transcripts in the cytoplasm. Researchers have taken advantage of this unique activation mechanism to monitor XBP1 activation, thereby UPR, in cell culture and transgenic models. Here we report a Tg(ef1α:xbp1δ-gfp) transgenic zebrafish line to monitor XBP1 activation using GFP as a reporter especially in zebrafish oocytes and developing embryos. The Tg(ef1α:xbp1δ-gfp) transgene was constructed using part of the zebrafish xbp1 cDNA containing the splicing element. ER stress induced splicing results in the cDNA encoding a GFP-tagged partial XBP1 without the transactivation activation domain (XBP1Δ-GFP). The results showed that xbp1 transcripts mainly exist as the spliced active isoform in unfertilized oocytes and zebrafish embryos prior to zygotic gene activation at 3 hours post fertilization. A strong GFP expression was observed in unfertilized oocytes, eyes, brain and skeletal muscle in addition to a weak expression in the hatching gland. Incubation of transgenic zebrafish embryos with (dithiothreitol) DTT significantly induced XBP1Δ-GFP expression. Collectively, these studies unveil the presence of maternal xbp1 splicing in zebrafish oocytes, fertilized eggs and early stage embryos. The Tg(ef1α:xbp1δ-gfp) transgenic zebrafish provides a useful model for in vivo monitoring xbp1 splicing during development and under ER stress conditions.

  20. Endoplasmic reticulum stress in the proapoptotic action of edelfosine in solid tumor cells.

    Science.gov (United States)

    Nieto-Miguel, Teresa; Fonteriz, Rosalba I; Vay, Laura; Gajate, Consuelo; López-Hernández, Silvia; Mollinedo, Faustino

    2007-11-01

    The endoplasmic reticulum (ER) has been posited as a potential anticancer target. The synthetic antitumor alkyl-lysophospholipid analogue edelfosine accumulates in the ER of solid tumor cells. This ER accumulation of the drug leads to the inhibition of phosphatidylcholine and protein synthesis, G(2)-M arrest, depletion of ER-stored Ca(2+), Bax up-regulation and activation, transcriptional factor growth arrest and DNA damage-inducible gene 153 up-regulation, caspase-4 and caspase-8 activation, and eventually to apoptosis. Edelfosine prompted ER stress apoptotic signaling, but not the survival unfolded protein response. Edelfosine also induced persistent c-Jun NH(2)-terminal kinase (JNK) activation. Gene transfer-mediated overexpression of apoptosis signal-regulating kinase 1, which plays a crucial role in ER stress, enhanced edelfosine-induced JNK activation and apoptosis. Inhibition of JNK, caspase-4, or caspase-8 activation diminished edelfosine-induced apoptosis. Edelfosine treatment led to the generation of the p20 caspase-8 cleavage fragment of BAP31, directing proapoptotic signals between the ER and the mitochondria. bax(-/-)bak(-/-) double-knockout cells fail to undergo edelfosine-induced ER-stored Ca(2+) release and apoptosis. Wild-type and bax(-/-)bak(-/-) cells showed similar patterns of phosphatidylcholine and protein synthesis inhibition, despite their differences in drug sensitivity. Thus, edelfosine-induced apoptosis is dependent on Bax/Bak-mediated ER-stored Ca(2+) release, but phosphatidylcholine and protein synthesis inhibition is not critical. Transfection-enforced expression of Bcl-X(L), which localizes specifically in mitochondria, prevented apoptosis without inhibiting ER-stored Ca(2+) release. These data reveal that edelfosine induces an ER stress response in solid tumor cells, providing novel insights into the edelfosine-mediated antitumor activity. Our data also indicate that mitochondria are indispensable for this edelfosine-induced cell

  1. Involvement of endoplasmic reticulum stress in formalin-induced pain is attenuated by 4-phenylbutyric acid

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    Zhou, Fan; Zhang, Wei; Zhou, Jianmei; Li, Meirong; Zhong, Feng; Zhang, Yun; Liu, Yuezhu; Wang, Yaping

    2017-01-01

    Background Endoplasmic reticulum (ER) stress is involved in many neurological and inflammatory responses. Peripheral inflammatory responses can induce central sensitization and trigger inflammatory pain. However, there is little research on the relationship between ER stress and inflammatory pain. In this study, we examined whether the ER stress response is involved in peripheral inflammatory pain using a formalin-induced rat pain model. Methods Rats were divided into the following five groups: control, formalin, formalin + vehicle, formalin + 4-phenylbutyric acid (4-PBA) (40 mg/kg) and formalin + 4-PBA (100 mg/kg). Formalin-induced pain was assessed behaviorally by recording licking activity. The expression levels of immunoglobulin-binding protein (BIP), activating transcription factor-6 (ATF6), phosphorylated inositol-requiring enzyme-1 (p-IRE1), phosphorylated protein kinase RNA-like ER kinase (p-PERK) and c-fos were quantitatively assessed by Western blot, and the distribution of BIP, ATF6 and c-fos in the lumbar enlargement of spinal cord were identified by immunohistochemistry in spinal dorsal horn slices. In addition, the concentrations of nitric oxide (NO) and prostaglandin E2 (PGE2) in the spinal cord were tested by biochemical measurement and enzyme-linked immunosorbent assay (ELISA), respectively. Results Intraperitoneal injection of 4-PBA at the dose of 100 mg/kg before formalin injection significantly decreased nociceptive behavior in the second phase compared with control, formalin, formalin + vehicle and formalin + 4-PBA (40 mg/kg) (Ppain and that inhibition of ER stress may attenuate central sensitization induced by peripheral inflammatory stimulation. PMID:28360534

  2. Exogenous taurine attenuates mitochondrial oxidative stress and endoplasmic reticulum stress in rat cardiomyocytes

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    Yujie Yang; Yue Zhang; Xiaoyu Liu; Ji Zuo; Keqiang Wang; Wen Liu; Junbo Ge

    2013-01-01

    Taurine,a conditionally essential amino acid,plays a critical role in cardiovascular function.Here we examined the effect of taurine on mitochondria and endoplasmic reticulum in rat cardiomyocytes during glucose deprivation (GD).Data showed that cell viability,intracellular taurine contents,and taurine transporter expression were decreased during GD.In contrast,an increase in reactive oxygen species and intracellular Ca2+ contents was observed.GD also caused disrupted mitochondrial membrane potential,apoptotic cell death,and dissociation of unfolded protein response (UPR)-relative proteins in cardiomyocytes.Signal transduction analysis showed that Bcl-2 family protein balance was disturbed,caspase-12 was activated and UPR-relative protein levels were up-regulated.Moreover,pre-treatment with 80 mM exogenous taurine attenuated GD effect in cardiomyocytes.Our results suggest that taurine have beneficial effects on inhibiting mitochondria-dependent cell apoptosis and UPR-associated cell apoptosis and might have clinical impfications on acute myocardial infarction in future.

  3. Glutamine treatment attenuates endoplasmic reticulum stress and apoptosis in TNBS-induced colitis.

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    Crespo, Irene; San-Miguel, Beatriz; Prause, Carolina; Marroni, Norma; Cuevas, María J; González-Gallego, Javier; Tuñón, María J

    2012-01-01

    Endoplasmic reticulum (ER) stress and apoptotic cell death play an important role in the pathogenesis and perpetuation of inflammatory bowel disease (IBD). We aimed to explore the potential of glutamine to reduce ER stress and apoptosis in a rat model of experimental IBD. Colitis was induced in male Wistar rats by intracolonic administration of 30 mg of 2,4,6-trinitrobenzene sulfonic acid (TNBS). Glutamine (25 mg/dL) was given by rectal route daily for 2 d or 7 d. Both oxidative stress (TBARS concentration and oxidised/reduced glutathione ratio) and ER stress markers (CHOP, BiP, calpain-1 and caspase-12 expression) increased significantly within 48 h of TNBS instillation, and glutamine attenuated the extent of the changes. Glutamine also inhibited the significant increases of ATF6, ATF4 and spliced XBP-1 mRNA levels induced by TNBS instillation. TNBS-colitis resulted in a significant increase in p53 and cytochrome c expression, and a reduced Bcl-xL expression and Bax/Bcl-2 ratio. These effects were significantly inhibited by glutamine. Treatment with the amino acid also resulted in significant decreases of caspase-9, caspase-8 and caspase-3 activities. Double immunofluorescence staining showed co-localization of CHOP and cleaved caspase-3 in colon sections. Phospho-JNK and PARP-1 expression was also significantly higher in TNBS-treated rats, and treatment with glutamine significantly decreased JNK phosphorylation and PARP-1 proteolysis. To directly address the effect of glutamine on ER stress and apoptosis in epithelial cells, the ER stress inducers brefeldin A and tunicamycin were added to Caco-2 cells that were treated with glutamine (5 mM and 10 mM). The significant enhancement in PERK, ATF6 phosphorylated IRE1, BiP and cleaved caspase-3 expression induced by brefeldin A and tunicamycin was partly prevented by glutamine. Data obtained indicated that modulation of ER stress signalling and anti-apoptotic effects contribute to protection by glutamine against damage

  4. Glutamine treatment attenuates endoplasmic reticulum stress and apoptosis in TNBS-induced colitis.

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    Irene Crespo

    Full Text Available Endoplasmic reticulum (ER stress and apoptotic cell death play an important role in the pathogenesis and perpetuation of inflammatory bowel disease (IBD. We aimed to explore the potential of glutamine to reduce ER stress and apoptosis in a rat model of experimental IBD. Colitis was induced in male Wistar rats by intracolonic administration of 30 mg of 2,4,6-trinitrobenzene sulfonic acid (TNBS. Glutamine (25 mg/dL was given by rectal route daily for 2 d or 7 d. Both oxidative stress (TBARS concentration and oxidised/reduced glutathione ratio and ER stress markers (CHOP, BiP, calpain-1 and caspase-12 expression increased significantly within 48 h of TNBS instillation, and glutamine attenuated the extent of the changes. Glutamine also inhibited the significant increases of ATF6, ATF4 and spliced XBP-1 mRNA levels induced by TNBS instillation. TNBS-colitis resulted in a significant increase in p53 and cytochrome c expression, and a reduced Bcl-xL expression and Bax/Bcl-2 ratio. These effects were significantly inhibited by glutamine. Treatment with the amino acid also resulted in significant decreases of caspase-9, caspase-8 and caspase-3 activities. Double immunofluorescence staining showed co-localization of CHOP and cleaved caspase-3 in colon sections. Phospho-JNK and PARP-1 expression was also significantly higher in TNBS-treated rats, and treatment with glutamine significantly decreased JNK phosphorylation and PARP-1 proteolysis. To directly address the effect of glutamine on ER stress and apoptosis in epithelial cells, the ER stress inducers brefeldin A and tunicamycin were added to Caco-2 cells that were treated with glutamine (5 mM and 10 mM. The significant enhancement in PERK, ATF6 phosphorylated IRE1, BiP and cleaved caspase-3 expression induced by brefeldin A and tunicamycin was partly prevented by glutamine. Data obtained indicated that modulation of ER stress signalling and anti-apoptotic effects contribute to protection by glutamine

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

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    Wang, Zhen; Wang, Hua; Xu, Zhong Mei; Ji, Yan-Li; Chen, Yuan-Hua; Zhang, Zhi-Hui; Zhang, Cheng; Meng, Xiu-Hong; Zhao, Mei; Xu, De-Xiang, E-mail: xudex@126.com

    2012-03-01

    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 blood 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-mediated ER

  6. Fucoidan induces cancer cell apoptosis by modulating the endoplasmic reticulum stress cascades.

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    Shaohua Chen

    Full Text Available Cancer metastasis is the main cause leading to disease recurrence and high mortality in cancer patients. Therefore, inhibiting metastasis process or killing metastatic cancer cells by inducing apoptosis is of clinical importance in improving cancer patient survival. Previous studies revealed that fucoidan, a fucose-rich polysaccharide isolated from marine brown alga, is a promising natural product with significant anti-cancer activity. However, little is known about the role of endoplasmic reticulum (ER stress in fucoidan-induced cell apoptosis.We reported that fucoidan treatment inhibits cell growth and induces apoptosis in cancer cells. Fucoidan treatments resulted in down-regulation of the glucose regulated protein 78 (GRP78 in the metastatic MDA-MB-231 breast cancer cells, and of the ER protein 29 (ERp29 in the metastatic HCT116 colon cancer cells. However, fucoidan treatment promoted ER Ca2+-dependent calmodulin-dependent kinase II (CaMKII phosphorylation, Bcl-associated X protein (Bax and caspase 12 expression in MDA-MB-231 cells, but not in HCT116 cells. In both types of cancer cells, fucoidan activated the phosphorylation of eukaryotic initiation factor 2 alpha (p-eIF2α\\CCAAT/enhancer binding protein homologous protein (CHOP pro-apoptotic cascade and inhibited the phosphorylation of inositol-requiring kinase 1 (p-IRE-1\\X-box binding proteins 1 splicing (XBP-1s pro-survival cascade. Furthermore, CHOP knockdown prevented DNA damage and cell death induced by fucoidan.Fucoidan exerts its anti-tumor function by modulating ER stress cascades. Contribution of ER stress to the fucoidan-induced cell apoptosis augments our understanding of the molecular mechanisms underlying its anti-tumour activity and provides evidence for the therapeutic application of fucoidan in cancer.

  7. Vertical sleeve gastrectomy reduces blood pressure and hypothalamic endoplasmic reticulum stress in mice

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    Anne K. McGavigan

    2017-03-01

    Full Text Available Bariatric surgery, such as vertical sleeve gastrectomy (VSG, causes remarkable improvements in cardiometabolic health, including hypertension remission. However, the mechanisms responsible remain undefined and poorly studied. Therefore, we developed and validated the first murine model of VSG that recapitulates the blood pressure-lowering effect of VSG using gold-standard radiotelemetry technology. We used this model to investigate several potential mechanisms, including body mass, brain endoplasmic reticulum (ER stress signaling and brain inflammatory signaling, which are all critical contributors to the pathogenesis of obesity-associated hypertension. Mice fed on a high-fat diet underwent sham or VSG surgery and radiotelemeter implantation. Sham mice were fed ad libitum or were food restricted to match their body mass to VSG-operated mice to determine the role of body mass in the ability of VSG to lower blood pressure. Blood pressure was then measured in freely moving unstressed mice by radiotelemetry. VSG decreased energy intake, body mass and fat mass. Mean arterial blood pressure (MAP was reduced in VSG-operated mice compared with both sham-operated groups. VSG-induced reductions in MAP were accompanied by a body mass-independent decrease in hypothalamic ER stress, hypothalamic inflammation and sympathetic nervous system tone. Assessment of gut microbial populations revealed VSG-induced increases in the relative abundance of Gammaproteobacteria and Enterococcus, and decreases in Adlercreutzia. These results suggest that VSG reduces blood pressure, but this is only partly due to the reduction in body weight. VSG-induced reductions in blood pressure may be driven by a decrease in hypothalamic ER stress and inflammatory signaling, and shifts in gut microbial populations.

  8. Cis-hydroxyproline-induced inhibition of pancreatic cancer cell growth is mediated by endoplasmic reticulum stress

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    Christoph Mueller; Joerg Emmrich; Robert Jaster; Dagmar Braun; Stefan Liebe; Gisela Sparmann

    2006-01-01

    AIM: To investigate the biological effects of cishydroxyproline (CHP) on the rat pancreatic carcinoma cell line DSL6A, and to examine the underlying molecular mechanisms.METHODS: The effect of CHP on DSL6A cell proliferation was assessed by using BrdU incorporation. The expression of focal adhesion kinase (FAK) was characterized by Western blotting and immunofluorescence.Induction of endoplasmic reticulum (ER) stress was investigated by using RT-PCR and Western blotting for the glucose-related protein-78 (GRP78) and growth arrest and DNA inducible gene (GADD153). Cell viability was determined through measuring the metabolic activity based on the reduction potential of DSL6A cells. Apoptosis was analyzed by detection of caspase-3 activation and cleavage of poly(ADP-ribose) polymerase (PARP) as well as DNA laddering.RESULTS: In addition to inhibition of proliferation,incubation with CHP induced proteolytic cleavage of FAK and a delocalisation of the enzyme from focal adhesions,followed by a loss of cell adherence. Simultaneously,we could show an increased expression of GRP78 and GADD153, indicating a CHP-mediated activation of the ER stress cascade in the DSL6A cell line. Prolonged incubation of DSL6A cells with CHP finally resulted in apoptotic cell death. Beside L-proline, the inhibition of intracellular proteolysis by addition of a broad spectrum protease inhibitor could abolish the effects of CHP on cellular functions and the molecular processes. In contrast, impeding the activity of apoptosis-executing caspases had no influence on CHP-mediated cell damage.CONCLUSION: Our data suggest that the initiation of ER stress machinery by CHP leads to an activation of intracellular proteolytic processes, including caspaseindependent FAK degradation, resulting in damaging pancreatic carcinoma cells.

  9. Endoplasmic reticulum stress responses differ in meninges and associated vasculature, striatum, and parietal cortex after a neurotoxic amphetamine exposure.

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    Thomas, Monzy; George, Nysia I; Saini, Upasana T; Patterson, Tucker A; Hanig, Joseph P; Bowyer, John F

    2010-08-01

    Amphetamine (AMPH) is used to treat attention deficit and hyperactivity disorders, but it can produce neurotoxicity and adverse vascular effects at high doses. The endoplasmic reticulum (ER) stress response (ERSR) entails the unfolded protein response, which helps to avoid or minimize ER dysfunction. ERSR is often associated with toxicities resulting from the accumulation of unfolded or misfolded proteins and has been associated with methamphetamine toxicity in the striatum. The present study evaluates the effect of AMPH on several ERSR elements in meninges and associated vasculature (MAV), parietal cortex, and striatum. Adult, male Sprague-Dawley rats were exposed to saline, environmentally induced hyperthermia (EIH) or four consecutive doses of AMPH that produce hyperthermia. Expression changes (mRNA and protein levels) of key ERSR-related genes in MAV, striatum, and parietal cortex at 3 h or 1 day postdosing were monitored. AMPH increased the expression of some ERSR-related genes in all tissues. Atf4 (activating transcription factor 4, an indicator of Perk pathway activation), Hspa5/Grp78 (Glucose regulated protein 78, master regulator of ERSR), Pdia4 (protein disulfide isomerase, protein-folding enzyme), and Nfkb1 (nuclear factor of kappa b, ERSR sensor) mRNA increased significantly in MAV and parietal cortex 3 h after AMPH. In striatum, Atf4 and Hspa5/Grp78 mRNA significantly increased 3 h after AMPH, but Pdia4 and Nfkb11 did not. Thus, AMPH caused a robust activation of the Perk pathway in all tissues, but significant Ire1 pathway activation occurred only after AMPH treatment in the parietal cortex and striatum. Ddit3/Chop, a downstream effector of the ERSR pathway related to the neurotoxicity, was only increased in striatum and parietal cortex. Conversely, Pdia4, an enzyme protective in the ERSR, was only increased in MAV. The overall ERSR manifestation varied significantly between MAV, striatum, and parietal cortex after a neurotoxic exposure to AMPH.

  10. Activation of AMP-activated protein kinase inhibits oxidized LDL-triggered endoplasmic reticulum stress in vivo.

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    Dong, Yunzhou; Zhang, Miao; Wang, Shuangxi; Liang, Bin; Zhao, Zhengxing; Liu, Chao; Wu, Mingyuan; Choi, Hyoung Chul; Lyons, Timothy J; Zou, Ming-Hui

    2010-06-01

    The oxidation of LDLs is considered a key step in the development of atherosclerosis. How LDL oxidation contributes to atherosclerosis remains poorly defined. Here we report that oxidized and glycated LDL (HOG-LDL) causes aberrant endoplasmic reticulum (ER) stress and that the AMP-activated protein kinase (AMPK) suppressed HOG-LDL-triggered ER stress in vivo. ER stress markers, sarcoplasmic/endoplasmic reticulum Ca(2+) ATPase (SERCA) activity and oxidation, and AMPK activity were monitored in cultured bovine aortic endothelial cells (BAECs) exposed to HOG-LDL or in isolated aortae from mice fed an atherogenic diet. Exposure of BAECs to clinically relevant concentrations of HOG-LDL induced prolonged ER stress and reduced SERCA activity but increased SERCA oxidation. Chronic administration of Tempol (a potent antioxidant) attenuated both SERCA oxidation and aberrant ER stress in mice fed a high-fat diet in vivo. Likewise, AMPK activation by pharmacological (5'-aminoimidazole-4-carboxymide-1-beta-d-ribofuranoside, metformin, and statin) or genetic means (adenoviral overexpression of constitutively active AMPK mutants) significantly mitigated ER stress and SERCA oxidation and improved the endothelium-dependent relaxation in isolated mouse aortae. Finally, Tempol administration markedly attenuated impaired endothelium-dependent vasorelaxation, SERCA oxidation, ER stress, and atherosclerosis in ApoE(-/-) and ApoE(-/-)/AMPKalpha2(-/-) fed a high-fat diet. We conclude that HOG-LDL, via enhanced SERCA oxidation, causes aberrant ER stress, endothelial dysfunction, and atherosclerosis in vivo, all of which are inhibited by AMPK activation.

  11. Endoplasmic reticulum stress participates in the progress of senescence and apoptosis of osteoarthritis chondrocytes.

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    Liu, Yake; Zhu, Hai; Yan, Xin; Gu, Haoye; Gu, Zhifeng; Liu, Fan

    2017-09-16

    Endoplasmic reticulum stress (ERS) has been shown to participate in many disease pathologies. Recent reports have reported that ERS exists in human osteoarthritis (OA) chondrocytes. During OA, chondrocytes exhibit increased level of some senescence marker, such as senescence-associated β-galactosidase (SA β-gal) activity. However, the persistence and accumulation of senescent cells in various tissues can also impair function and have been involved in the pathogenesis of many age-related diseases, including OA. In this present study, we used IL-1β (10 ng/ml) to mimic OA chondrocytes and we found that IL-1β stimulated chondrocytes caused the increasing expression of ADAMTS5 and MMP13, decreasing COL2A1 expression, which were in accord with OA chondrocytes changes. Our data also showed that ERS is involved in the OA chondrocytes, SA β-gal activity significantly increases and inhibition of ERS can decrease the SA β-gal activity, apoptosis of OA chondrocytes and increase cell viability. These results help us to open new perspectives for the development of molecular-targeted treatment approaches and thus present an effective novel therapeutic approach for OA. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Effects of endoplasmic reticulum stress and related apoptosis on selective death of dopaminergic neurons

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    Lan Wang; Shenggang Sun; Xuebing Cao; Zhentao Zhang; Li Xu

    2006-01-01

    Objective: To explore the mechanism of endoplasmic reticulum stress (ERS) response and related apoptosis in dopaminergic neurons death. Methods: Nerve growth factor (NGF)-treatedPC12 cells were treated with 6-OHDA, MPP+ and rotenone. MTr assay and flow cytometry were used to measure the cell viability and the rate of celluar apoptosis induced by those neurotoxins. The expression of ERS-related gene XBP1, Grp78, CHOP, caspase-12 in drug-treated group and reserpine preincubation group was determined with RT-polymerase chain reaction (RT-PCR) and immunohistochemistry. Results: After the exposure to different toxins, the viability of PC12 cells were decreased by 52%, 44%, 40% at 100μM6-OHDA, 75 μM MPP+, 20 nM rotenone for 24 h respectively. FCM assay confirmed time-dependent cell apoptosis (P < 0.01 ). The gene and protein expression of XBP1, Grp78 in drug-treated group were significantly increased and reached their peaks 8 h after the treatment(P < 0.05).The expression levels of CHOP and caspase-12 gene were increased 16-24 h after the treatment(P < 0.01 ), but the expression level of caspase-12 was inhibited by reserpine preincubayion (P < 0.05). Conclusion: The excessive ERS and relative activated cell apoptosis pathway may be associated with selective death of dopaminergic neurons.

  13. Ursolic acid inhibits the development of nonalcoholic fatty liver disease by attenuating endoplasmic reticulum stress.

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    Li, Jian-Shuang; Wang, Wen-Jun; Sun, Yu; Zhang, Yu-Hao; Zheng, Ling

    2015-05-01

    Ursolic acid (UA) is a natural pentacyclic triterpenoid compound, which is enriched with many herbs and plants, such as apple, cranberry and olive. UA performs multiple biological activities including anti-oxidation, anti-inflammation, anti-cancer and hepatoprotection. However, the exact mechanism underlying the hepatoprotective activity of UA remains unclear. In this study, the effects of UA on the development of nonalcoholic fatty liver disease (NAFLD) were investigated. In vivo, UA treatment (0.14%, w/w) significantly decreased the liver weight, serum levels of ALT/AST and hepatic steatosis in db/db mice (a type 2 diabetic mouse model). In vitro, UA treatment (10-30 μg ml(-1)) significantly decreased palmitic acid induced intracellular lipid accumulation in L02 cells. Our results suggested that the beneficial effects of UA on NAFLD may be due to its ability to increase lipid β-oxidation and to inhibit the hepatic endoplasmic reticulum (ER) stress. Together, UA may be further considered as a natural compound for NAFLD treatment.

  14. Guanxinkang Decoction Exerts Its Antiatherosclerotic Effect Partly through Inhibiting the Endoplasmic Reticulum Stress

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    Hao Wang

    2014-01-01

    Full Text Available Purpose. To investigate the antiatherosclerotic effect of Guanxinkang (GXK decoction on the apoptosis, mitochondrial membrane potential (MMP, and endoplasmic reticulum stress (ERS of human umbilical vein endothelial cells (HUVEC pretreated with homocysteinemia (HCY. Materials and Methods. HUVEC were randomly divided into 5 groups: (1 blank control group (control, (2 model control group (model, (3 GXK low dose group, (4 GXK medium dose group, and (5 GXK high dose group. For the three GXK groups, HCY was given to reach the concentration of 3.0 mmol/L after HUVEC had been incubated with rabbit serum containing GXK for two hours. At 3, 6, 12, and 24 h after HCY had been incubated with the cells, the HUVEC were collected for test of the apoptosis rate, MMP, and GRP78 protein (reflecting ERS. Results. In the model control group, the apoptosis rate and GRP 78 protein expression of HUVEC significantly increased (P<0.05, while MMP significantly decreased (P<0.05 compared with the blank control group. After GXK treatment of medium and high doses, the apoptosis rate and the GRP 78 protein expression significantly (P<0.05 decreased, while MMP significantly increased (P<0.05 in a time-dependent manner compared with the model control group. Conclusion. GXK can antagonize the injury of HUVEC caused by HCY and the antagonism effect increases with the concentration and treatment duration of GXK, with the possible mechanism of GXK antagonism being through inhibiting ERS caused by HCY.

  15. Spermine inhibits Endoplasmic Reticulum Stress - induced Apoptosis: a New Strategy to Prevent Cardiomyocyte Apoptosis

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    Can Wei

    2016-02-01

    Full Text Available Background/Aims: Endoplasmic reticulum stress (ERS plays an important role in the progression of acute myocardial infarction (AMI, in part by mediating apoptosis. Polyamines, including putrescine, spermidine, and spermine, are polycations with anti-oxidative, anti-aging, and cell growth-promoting activities. This study aimed to determine the mechanisms by which spermine protects against ERS-induced apoptosis in rats following AMI. Methods and Results: AMI was established by ligation of the left anterior descending coronary artery (LAD in rats, and exogenous spermine was administered by intraperitoneal injection (2.5 mg/ml daily for 7 days pre-AMI. Spermine treatment limited infarct size, attenuated cardiac troponin I and creatinine kinase-MB release, improved cardiac function, and decreased ERS and apoptosis related protein expression. Isolated cardiomyocytes subjected to hypoxia showed significant increase in reactive oxygen species (ROS and the expression of apoptosis and ERS related proteins; these effects occurred through PERK and eIF2α phosphorylation. The addition of spermine attenuated cardiomyocyte apoptosis, suppressed the production of ROS, and inhibited ERS related pathways. Conclusions: Spermine was an effective pre-treatment strategy to attenuate cardiac ERS injury in rats, and the cardioprotective mechanism occurring through inhibition of ROS production and down regulation of the PERK-eIF2α pathway. These findings provide a novel target for the prevention of apoptosis in the setting of AMI.

  16. Involvement of Endoplasmic Reticulum Stress in Uremic Cardiomyopathy: Protective Effects of Tauroursodeoxycholic Acid

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    Wei Ding

    2016-01-01

    Full Text Available Background/Aims: Uremic cardiomyopathy (UCM is a complication in chronic kidney disease. We investigated if endoplasmic reticulum stress (ERS is involved in UCM, and determined the efficacy of tauroursodeoxycholic acid (TUDCA in UCM prevention. Methods: Mice were divided randomly into three groups: sham (saline, i.p, 5/6 nephrectomized (Nx (saline, i.p and Nx+TUDCA (250 mg/kg/day, i.p.. Renal function was assessed by measuring serum creatinine, blood urea nitrogen and by periodic acid-Schiff reagent staining. Histologic examination of cardiac fibrosis and apoptosis was determined by Masson's trichrome and TUNEL assay. Cardiac function was evaluated by echocardiography. Fibrotic factors (transforming growth factor-β, fibronectin, collagen I/IV were evaluated by real-time PCR. ERS-related proteins were measured by western blotting. Results: Impaired renal function and cardiac dysfunction were shown in 5/6 nephrectomy mice but were improved significantly by TUDCA. 5/6 nephrectomy mice exhibited marked cardiomyocyte apoptosis, cardiac fibrosis and elevated pro-fibrotic factors. ERS markers (GRP78, GRP94, P-PERK, P-eIF2a and ERS-induced apoptosis pathways (activation of CHOP and caspase-12 were increased significantly in 5/6 nephrectomy mice, and TUDCA treatment blunted these changes. Conclusions: ERS has a key role in UCM, and the cardioprotective role of TUDCA is related to inhibition of ERS-induced apoptosis by inhibition of CHOP and caspase-12 pathways.

  17. Overexpressed PLTP in macrophage may promote cholesterol accumulation by prolonged endoplasmic reticulum stress.

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    Yang, Xinquan; Yu, Yang; Wang, Daxin; Qin, Shucun

    2017-01-01

    It is well known that phospholipid transfer protein (PLTP) is involved in the lipid metabolism and development of atherosclerosis (AS). Abundant PLTP is considered to be expressed on the foam cells derived from monocyte/macrophages in atherosclerotic plaques, suggesting that high level of active PLTP may promote the formation of foam cells. However, the exact role of PLTP on the process of macrophage derived foam cell formation remains unclear. The accumulation of free cholesterol (FC) in the cytoplasm may lead to the prolonged endoplasmic reticulum stress (ERs) and the imbalance of intracellular cholesterol homeostasis. Different PLTP level definitely alternates the phospholipids (PL) and cholesterol level in plasma, strongly suggesting that active PLTP may change the level of FC and PL intracellularly, which subsequently induced the ERs in macrophage. Thus, we hypothesize that high level of PLTP may promote the accumulation of cholesterol in macrophage via the alteration ratio of FC to PL. Therefore, validating this hypothesis may clarify the role of PLTP in macrophage ERs in AS and also raise a novel strategy in the regression of AS plaques via restoring intracellular membrane lipid homeostasis and attenuating ERs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Chronic Intermittent Hypobaric Hypoxia Improves Cardiac Function through Inhibition of Endoplasmic Reticulum Stress.

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    Yuan, Fang; Zhang, Li; Li, Yan-Qing; Teng, Xu; Tian, Si-Yu; Wang, Xiao-Ran; Zhang, Yi

    2017-08-11

    We investigated the role of endoplasmic reticulum stress (ERS) in chronic intermittent hypobaric hypoxia (CIHH)-induced cardiac protection. Adult male Sprague-Dawley rats were exposed to CIHH treatment simulating 5000 m altitude for 28 days, 6 hours per day. The heart was isolated and perfused with Langendorff apparatus and subjected to 30-min ischemia followed by 60-min reperfusion. Cardiac function, infarct size, and lactate dehydrogenase (LDH) activity were assessed. Expression of ERS molecular chaperones (GRP78, CHOP and caspase-12) was assayed by western blot analysis. CIHH treatment improved the recovery of left ventricular function and decreased cardiac infarct size and activity of LDH after I/R compared to control rats. Furthermore, CIHH treatment inhibited over-expression of ERS-related factors including GRP78, CHOP and caspase-12. CIHH-induced cardioprotection and inhibition of ERS were eliminated by application of dithiothreitol, an ERS inducer, and chelerythrine, a protein kinase C (PKC) inhibitor. In conclusion CIHH treatment exerts cardiac protection against I/R injury through inhibition of ERS via PKC signaling pathway.

  19. Salinomycin induces cell death with autophagy through activation of endoplasmic reticulum stress in human cancer cells.

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    Li, Tianliang; Su, Ling; Zhong, Ning; Hao, Xuexi; Zhong, Diansheng; Singhal, Sunil; Liu, Xiangguo

    2013-07-01

    Salinomycin is perhaps the first promising compound that was discovered through high throughput screening in cancer stem cells. This novel agent can selectively eliminate breast and other cancer stem cells, though the mechanism of action remains unclear. In this study, we found that salinomycin induced autophagy in human non-small cell lung cancer (NSCLC) cells. Furthermore, we demonstrated that salinomycin stimulated endoplasmic reticulum stress and mediated autophagy via the ATF4-DDIT3/CHOP-TRIB3-AKT1-MTOR axis. Moreover, we found that the autophagy induced by salinomycin played a prosurvival role in human NSCLC cells and attenuated the apoptotic cascade. We also showed that salinomycin triggered more apoptosis and less autophagy in A549 cells in which CDH1 expression was inhibited, suggesting that the inhibition of autophagy might represent a promising strategy to target cancer stem cells. In conclusion, these findings provide evidence that combination treatment with salinomycin and pharmacological autophagy inhibitors will be an effective therapeutic strategy for eliminating cancer cells as well as cancer stem cells.

  20. Involvement of Endoplasmic Reticulum Stress in TULP1 Induced Retinal Degeneration.

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    Glenn P Lobo

    Full Text Available Inherited retinal disorders (IRDs result in severe visual impairments in children and adults. A challenge in the field of retinal degenerations is identifying mechanisms of photoreceptor cell death related to specific genetic mutations. Mutations in the gene TULP1 have been associated with two forms of IRDs, early-onset retinitis pigmentosa (RP and Leber congenital amaurosis (LCA. TULP1 is a cytoplasmic, membrane-associated protein shown to be involved in transportation of newly synthesized proteins destined for the outer segment compartment of photoreceptor cells; however, how mutant TULP1 causes cell death is not understood. In this study, we provide evidence that common missense mutations in TULP1 express as misfolded protein products that accumulate within the endoplasmic reticulum (ER causing prolonged ER stress. In an effort to maintain protein homeostasis, photoreceptor cells then activate the unfolded protein response (UPR complex. Our results indicate that the two major apoptotic arms of the UPR pathway, PERK and IRE1, are activated. Additionally, we show that retinas expressing mutant TULP1 significantly upregulate the expression of CHOP, a UPR signaling protein promoting apoptosis, and undergo photoreceptor cell death. Our study demonstrates that the ER-UPR, a known mechanism of apoptosis secondary to an overwhelming accumulation of misfolded protein, is involved in photoreceptor degeneration caused by missense mutations in TULP1. These observations suggest that modulating the UPR pathways might be a strategy for therapeutic intervention.

  1. Endoplasmic reticulum stress induced by Thapsigargin in vascular smooth muscle cells of rat coronary artery

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao-yan; DENG Chun-yu; JIANG Li

    2016-01-01

    AIM:To establish the endoplasmic reticulum stress ( ERS) cell model in vascular smooth muscle cells ( VSMCs) of Sprague-Dawley (SD) rats.METHODS:Under sterile condition, the coronary arteries were isolated from SD rats .The primary VSMCs were cultured by tissue-sticking method , and observed the basic morphological characteristics under optical microscope .The marker proteins of VSMCs including α-smooth muscle actin (α-SMA) and smooth muscle myosin heavy chain ( SM-MHC) were identified by immuno-fluorescence technique .VSMCs were treated with thapsigargin (0.5, 1 and 2 μmol/L) for 24 h, and the expression levels of binding immunoglobulin protein (BiP) and C/EBP homologus protein (CHOP), the marker molecules of ERS, were detected using Western blotting.RESULTS:VSMCs climbed out from coronary artery tissues after about six days , and the cells had a nice state and formed the VSMC-like typical "peak valley".The results of immunofluorescence technique show that the marker proteins of VSMCs ,α-SMA and SM-MHC were expressed significantly .The results of Western blotting show that the protein expression levels of BiP and CHOP were increased by thapsigargin in a dose-dependent manner .CONCLUSION:VSMCs can be successfully cultured by tissue-sticking method and built the ERS model induced by thapsigargin .

  2. Effect of inositol requiring enzyme 1-mediated endoplasmic reticulum stress in liver cell apoptosis of experimental fulminant hepatic failure and its significance

    Institute of Scientific and Technical Information of China (English)

    甄真

    2013-01-01

    Objective To study the role of inositol requiring enzyme 1(IRE1)-mediated endoplasmic reticulum stress on hepatocyte apoptosis of experimental fulminant hepatic failure(FHF). Methods Thirty male depuratory Wistar

  3. Glucosamine-induced endoplasmic reticulum stress affects GLUT4 expression via activating transcription factor 6 in rat and human skeletal muscle cells

    DEFF Research Database (Denmark)

    Raciti, G A; Iadicicco, C; Ulianich, L

    2010-01-01

    Glucosamine, generated during hyperglycaemia, causes insulin resistance in different cells. Here we sought to evaluate the possible role of endoplasmic reticulum (ER) stress in the induction of insulin resistance by glucosamine in skeletal muscle cells....

  4. Disturbance of hippocampal H2S generation contributes to CUMS-induced depression-like behavior: involvement in endoplasmic reticulum stress of hippocampus

    National Research Council Canada - National Science Library

    Huiying Tan Wei Zou Jiamei Jiang Ying Tian Zhifang Xiao Lili Bi Haiying Zeng Xiaoqing Tang

    2015-01-01

    .... Excessive and prolonged endoplasmic reticulum (ER) stress triggers cell death. Hydrogen sulfide (H2S), the third endogenous signaling gasotransmitter, plays an import- ant role in brain functions as a neuromodulator and a neuroprotectant...

  5. Picosecond pulsed electric fields induce apoptosis in HeLa cells via the endoplasmic reticulum stress and caspase-dependent signaling pathways.

    Science.gov (United States)

    Chen, Wen-Juan; Xiong, Zheng-Ai; Zhang, Min; Yao, Chen-Guo; Zhao, Zhong-Yong; Hua, Yuan-Yuan; Zhou, Wei

    2013-03-01

    The non-invasive treatment of tumors with preserved fertility holds great promise. The application of pulsed electric field (PEF) is a new biomedical engineering technique for tumor therapy. Picosecond pulsed electric fields (psPEF) can be transferred to target deep tissue non-invasively and precisely; however, research of the biological effects of psPEF on cells is limited. Electric theory predicts that when the pulse duration decreases to nanoseconds and picoseconds, it will mainly affect organelles and lead to intracellular electromanipulations. Previous studies have shown that psPEF targets the mitochondria and induces apoptosis through a mitochondrial-mediated pathway in HeLa cells. The endoplasmic reticulum is also involved in the intrinsic pathways of apoptosis. In the present study, HeLa cells were exposed to psPEF to investigate the underlying mechanisms of apoptosis. MTT assay demonstrated that psPEF displayed strong growth inhibitory effects on HeLa cells. Treatment with psPEF led to marked cell apoptosis and cell cycle arrest at the G2/M phase. In addition, psPEF affected the phosphorylation levels of endoplasmic reticulum sensors and upregulated the expression of glucose-regulated protein 78 (GRP78), glucose-regulated protein 94 (GRP94) and CCAAT enhancer-binding protein (C/EBP) homologous protein (CHOP). These changes were accompanied by the elevation of intracellular Ca2+ concentrations. Furthermore, the activation of caspase-12, -9 and -3, led to the release of cytochrome c, as well as the upregulation of Bax and the downregulation of Bcl-2, as observed in the HeLa cells. Taken together, these data suggest that psPEF is an efficient apoptosis-inducing agent for HeLa cells, which exerts its effects, at least partially, via the endoplasmic reticulum stress and caspase-dependent signaling pathways.

  6. Silica nanoparticles induce endoplasmic reticulum stress response and activate mitogen activated kinase (MAPK signalling

    Directory of Open Access Journals (Sweden)

    Verena Christen

    2016-01-01

    Full Text Available Humans may be exposed to engineered silica nanoparticles (SiO2-NPs but potential adverse effects are poorly understood, in particular in relation to cellular effects and modes of action. Here we studied effects of SiO2-NPs on cellular function in human hepatoma cells (Huh7. Exposure for 24 h to 10 and 50 μg/ml SiO2-NPs led to induction of endoplasmic reticulum (ER stress as demonstrated by transcriptional induction of DNAJB9, GADD34, CHOP, as well as CHOP target genes BIM, CHAC-1, NOXA and PUMA. In addition, CHOP protein was induced. In addition, SiO2-NPs induced an inflammatory response as demonstrated by induction of TNF-α and IL-8. Activation of MAPK signalling was investigated employing a PCR array upon exposure of Huh7 cells to SiO2-NPs. Five of 84 analysed genes, including P21, P19, CFOS, CJUN and KSR1 exhibited significant transcriptional up-regulation, and 18 genes a significant down-regulation. Strongest down-regulation occurred for the proto-oncogene BRAF, MAPK11, one of the four p38 MAPK genes, and for NFATC4. Strong induction of CFOS, CJUN, FRA1 and CMYC was found after exposure to 50 μg/ml SiO2-NPs for 24 h. To analyse for effects derived from up-regulation of TNF-α, Huh7 cells were exposed to SiO2-NPs in the presence of the TNF-α inhibitor sauchinone, which reduced the induction of the TNF-α transcript by about 50%. These data demonstrate that SiO2-NPs induce ER stress, MAPK pathway and lead to inflammatory reaction in human hepatoma cells. Health implications of SiO2-NPs exposure should further be investigated for a risk assessment of these frequently used nanoparticles.

  7. Melatonin Activates Endoplasmic Reticulum Stress and Apoptosis in Rats with Diethylnitrosamine-Induced Hepatocarcinogenesis.

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    Andrea Janz Moreira

    Full Text Available Hepatocellular carcinoma (HCC is one of the most lethal human cancers worldwide because of its high incidence, its metastatic potential and the low efficacy of conventional treatment. Inactivation of apoptosis is implicated in tumour progression and chemotherapy resistance, and has been linked to the presence of endoplasmic reticulum stress. Melatonin, the main product of the pineal gland, exerts anti-proliferative, pro-apoptotic and anti-angiogenic effects in HCC cells, but these effects still need to be confirmed in animal models. Male Wistar rats in treatment groups received diethylnitrosamine (DEN 50 mg/kg intraperitoneally twice/once a week for 18 weeks. Melatonin was given in drinking water at 1 mg/kg/d, beginning 5 or 12 weeks after the start of DEN administration. Melatonin improved survival rates and successfully attenuated liver injury, as shown by histopathology, decreased levels of serum transaminases and reduced expression of placental glutathione S-transferase. Furthermore, melatonin treatment resulted in a significant increase of caspase 3, 8 and 9 activities, polyadenosine diphosphate (ADP ribose polymerase (PARP cleavage, and Bcl-associated X protein (Bax/Bcl-2 ratio. Cytochrome c, p53 and Fas-L protein concentration were also significantly enhanced by melatonin. Melatonin induced an increased expression of activating transcription factor 6 (ATF6, C/EBP-homologous protein (CHOP and immunoglobulin heavy chain-binding protein (BiP, while cyclooxygenase (COX-2 expression decreased. Data obtained suggest that induction of apoptosis and ER stress contribute to the beneficial effects of melatonin in rats with DEN-induced HCC.

  8. Calreticulin Translocation Aggravates Endoplasmic Reticulum Stress-associated Apoptosis during Cardiomyocyte Hypoxia/Reoxygenation

    Institute of Scientific and Technical Information of China (English)

    Fei-Fei Xu; Xiu-Hua Liu

    2015-01-01

    Background:Calreticulin (CRT) is major Ca2+-binding chaperone mainly resident in the endoplasmic reticulum (ER) lumen.Recently,it has been shown that non-ER CRT regulates a wide array of cellular responses.We previously found that CRT was up-regulated during hypoxia/reoxygenation (H/R) and this study was aimed to investigate whether CRT nuclear translocation aggravates ER stress (ERS)-associated apoptosis during H/R injury in neonatal rat cardiomyocytes.Methods:Apoptosis rate and lactate dehydrogenase (LDH) leakage in culture medium were measured as indices of cell injury.Immunofluorescence staining showed the morphological changes of ER and intracellular translocation of CRT.Western blotting or reverse transcription polymerase chain reaction was used to detect the expression of target molecules.Results:Compared with control,H/R increased apoptosis rate and LDH activity.The ER became condensed and bubbled,and CRT translocated to the nucleus.Western blotting showed up-regulation of CRT,Nrf2,activating transcription factor 4 (ATF4),CHOP and caspase-12 expression after H/R.Exogenous CRT overexpression induced by plasmid transfection before H/R increased cell apoptosis,LDH leakage,ER disorder,CRT nuclear translocation and the expression of ERS-associated molecules.However,administration of the ERS inhibitor,taurine,or CRT siRNA alleviated cell injury,ER disorder,and inhibited ERS-associated apoptosis.Conclusions:Our results indicated that during H/R stress,CRT translocation increases cell apoptosis and LDH leakage,aggravates ER disorder,up-regulates expression of nuclear transcription factors,Nrf2 and ATF4,and activates ERS-associated apoptosis.

  9. Effects of lead exposure on placental cellular apoptosis and endoplasmic reticulum stress in rats

    Institute of Scientific and Technical Information of China (English)

    Wang Yunying; Hu Haiyan; Li Hong; Ma Haiyan; Xu Fengsen; Qu Baoming

    2014-01-01

    Background Lead exposure during pregnancy contributes to fetal abortion and/or teratogenesis.Endoplasmic reticulum (ER) apoptosis can be induced by various pathological conditions when ER function is disturbed.However,it is unclear whether ER stress and apoptosis play a role in the etiology of lead-exposed disease status.We aimed to investigate whether lead induced placental apoptosis and subsequent toxicity is initiated by ER apoptosis via caspase-12.Methods Sixty-three female Wistar rats were exposed to lead in drinking water during various gestational periods.Blood lead level was determined by atomic absorption spectrophotometry.Placental cytoplasmic organelles were examined by electronic microscopy.Placental caspase-12 mRNA expression was evaluated by qRT-PCR.TUNEL assay was used to determine the placental apoptosis.Results Lead exposure significant induced ER apoptosis compared to that of the controls (P <0.05),accompanied with increased caspase-12 mRNA expression.Significant differences of caspase-12 mRNA expression levels were observed among the four groups (F=13.78,P <0.05).Apoptotic index (AI) was significantly increased in experimental groups compared to that of the controls (F=96.15,P <0.05).In lead-exposed groups,trophoblast cells underwent degeneration and fibrin deposition; Mitochondria were swollen and decreased in number; ER swelling,expansion,and vacuolization were observed.Conclusion Lead exposure contributes to placental apoptosis,as well as increased caspase-12 mRNA expression,which in turn promoted ER stress.

  10. Stress Sensors and Signal Transducers in Cyanobacteria

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    Sergey Kryazhov

    2010-03-01

    Full Text Available In living cells, the perception of environmental stress and the subsequent transduction of stress signals are primary events in the acclimation to changes in the environment. Some molecular sensors and transducers of environmental stress cannot be identified by traditional and conventional methods. Based on genomic information, a systematic approach has been applied to the solution of this problem in cyanobacteria, involving mutagenesis of potential sensors and signal transducers in combination with DNA microarray analyses for the genome-wide expression of genes. Forty-five genes for the histidine kinases (Hiks, 12 genes for serine-threonine protein kinases (Spks, 42 genes for response regulators (Rres, seven genes for RNA polymerase sigma factors, and nearly 70 genes for transcription factors have been successfully inactivated by targeted mutagenesis in the unicellular cyanobacterium Synechocystis sp. PCC 6803. Screening of mutant libraries by genome-wide DNA microarray analysis under various stress and non-stress conditions has allowed identification of proteins that perceive and transduce signals of environmental stress. Here we summarize recent progress in the identification of sensory and regulatory systems, including Hiks, Rres, Spks, sigma factors, transcription factors, and the role of genomic DNA supercoiling in the regulation of the responses of cyanobacterial cells to various types of stress.

  11. 内质网应激在心理应激中的作用%The role of endoplasmic reticulum stress in psychological stress

    Institute of Scientific and Technical Information of China (English)

    钟静玫; 白洁

    2012-01-01

    The psychological stress could result in psychological diseases and physiological diseases. And the psychological stress could cause endoplasmic reticulum stress by a series of reactions. The endoplasmic reticulum stress play roles in psychophysiological disorders, mental illnesses and neural degeneration diseases by mediating inflammation, apoptosis and the other processes of pathophysiology. This work reviewed some molecular mechanisms on the endoplasmic reticulum stress playing roles in the diseases related with the psychological stress.%心理应激可以造成心理疾病与生理疾病.心理应激通过一系列反应导致内质网应激.内质网应激通过炎症、凋亡等过程导致心身疾病、心理疾病、神经退行性疾病.本文将对内质网应激在心理应激相关疾病中的作用的分子机理做一综述.

  12. Endoplasmic reticulum stress is involved in podocyte apoptosis induced by saturated fatty acid palmitate

    Institute of Scientific and Technical Information of China (English)

    TAO Jian-ling; WEN Yu-bing; SHI Bing-yang; ZHANG Hong; RUAN Xiong-zhong; LI Hang; LI Xue-mei; DONG Wen-ji; LI Xue-wang

    2012-01-01

    Background Podocyte apoptosis is recently indicated as an early phenomenon of diabetic nephropathy.Pancreatic β-cells exposed to saturated free fatty acid palmitate undergo irreversible endoplasmic reticulum (ER) stress and consequent apoptosis,contributing to the onset of diabetes.We hypothesized that palmitate could induce podocyte apoptosis via ER stress,which initiates or aggravates proteinuria in diabetic nephropathy.Methods Podocyte apoptosis was detected by 4',6-diamidio-2-phenylindole (DAPI) stained apoptotic cell count and Annexin V-PI stain.The expressions of ER molecule chaperone glucose-regulated protein 78 (GRP78),indicators of ER-associated apoptosis C/EBP homologous protein (CHOP),and Bcl-2 were assayed by Western blotting and real-time PCR.GRP78 and synaptopodin were co-localized by immunofluorescence stain.Results Palmitate significantly increased the percentage of cultured apoptotic murine podocytes time-dependently when loading 0.75 mmol/L (10 hours,13 hours,and 15 hours compared with 0 hour,P <0.001) and dose-dependently when loading palmitate ranging from 0.25 to 1.00 mmol/L for 15 hours (compared to control,P <0.001).Palmitate time-dependently and dose-dependently increased the protein expression of GRP78 and CHOP,and decreased that of Bcl-2.Palmitate loading ranging from 0.5 to 1.0 mmol/L for 12 hours significantly increased mRNA of GRP78 and CHOP,and decreased that of Bcl-2 compared to control (P <0.001),with the maximum concentration being 0.75 mmol/L.Palmitate 0.5 mmol/L loading for 3 hours,8 hours,and 12 hours significantly increased mRNA of GRP78 and CHOP,and decreased that of Bcl-2 compared to 0 hour (P <0.001),with the maximum effect at 3 hours.Confocal microscopy demonstrated that GRP78 expression was significantly increased when exposed to 0.5 mmol/L of palmitate for 8 hours compared to control.Conclusion Palmitate could induce podocyte apoptosis via ER stress,suggesting podocyte apoptosis and consequent proteinuria caused

  13. Mechanical strain downregulates C/EBPβ in MSC and decreases endoplasmic reticulum stress.

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    Maya Styner

    Full Text Available Exercise prevents marrow mesenchymal stem cell (MSC adipogenesis, reversing trends that accompany aging and osteoporosis. Mechanical input, the in-vitro analogue to exercise, limits PPARγ expression and adipogenesis in MSC. We considered whether C/EBPβ might be mechanoresponsive as it is upstream to PPARγ, and also is known to upregulate endoplasmic reticulum (ER stress. MSC (C3H10T1/2 pluripotent cells as well as mouse marrow-derived MSC were cultured in adipogenic media and a daily mechanical strain regimen was applied. We demonstrate herein that mechanical strain represses C/EBPβ mRNA (0.6-fold ±0.07, p<0.05 and protein (0.4-fold ±0.1, p<0.01 in MSC. SiRNA silencing of β-catenin prevented mechanical repression of C/EBPβ. C/EBPβ overexpression did not override strain's inhibition of adipogenesis, which suggests that mechanical control of C/EBPβ is not the primary site at which adipogenesis is regulated. Mechanical inhibition of C/EBPβ, however, might be critical for further processes that regulate MSC health. Indeed, overexpression of C/EBPβ in MSC induced ER stress evidenced by a dose-dependent increase in the pro-apoptotic CHOP (protein 4-fold ±0.5, p<0.05 and a threshold reduction in the chaperone BiP (protein 0.6-fold ±0.1, p = 0.2; mRNA 0.3-fold ±0.1, p<0.01. ChIP-seq demonstrated a significant association between C/EBPβ and both CHOP and BiP genes. The strain regimen, in addition to decreasing C/EBPβ mRNA (0.5-fold ±0.09, p<0.05, expanded ER capacity as measured by an increase in BiP mRNA (2-fold ±0.2, p<0.05 and protein. Finally, ER stress induced by tunicamycin was ameliorated by mechanical strain as demonstrated by decreased C/EBPβ, increased BiP and decreased CHOP protein expression. Thus, C/EBPβ is a mechanically responsive transcription factor and its repression should counter increases in marrow fat as well as improve skeletal resistance to ER stress.

  14. RU486 Reverses Emotional Disorders by Influencing Astrocytes and Endoplasmic Reticulum Stress in Chronic Restraint Stress Challenged Rats

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    Liru Dong

    2017-06-01

    Full Text Available Aims: To investigate the effect of RU486 (mifepristone on emotional disorders in chronic restraint stress-induced rats and to explore the mechanisms of that phenomenon. Methods: For this purpose, 80 healthy male Sprague Dawley rats were randomly divided into four groups: the normal group (Con group, The Con group members received no treatment, eating and drinking freely, the chronic restraint stress group (CRS group, normal Sprague Dawley rats treated with chronic restraint stress, 6 h/day for 21days, the propylene glycol group (CRS+propylene glycol and the RU486 group (CRS+RU486. RU486 or propylene glycol was administered 30 mins before each CRS procedure. Twenty-four hours after CRS exposure, we investigated the effects of CRS on the anxiety-like behavior using an elevated plus-maze (EPM. To explore the mechanisms of RU486 on anxiety, we measured the expression of glial fibrillary acid protein (GFAP and β-subunit of S100 (S100β via immunohistochemistry and western blot analysis. Apoptosis was demonstrated by flow cytometry. In addition, endoplasmic reticulum (ER stress markers, glucose regulated protein 78 (GRP78, C/EBP homologous protein (CHOP and Cysteine aspartic acid specific protease-12 (Caspase-12, were detected by western blot analysis. Results: Compared to the control group, rats in the CRS and propylene glycol group showed decreased exploratory behavior on the open arms during EPM testing, and these reductions were accompanied by significantly reduced GFAP and S100β expression, increased apoptosis and GRP78, CHOP, and caspase-12 expression in the amygdala. However, RU486 increases the exploratory behavior and reverses the changes of GFAP, S100β, GRP78, CHOP, and caspase-12 and protects cells against apoptosis. Conclusions: Taken together, these data suggest that exposure to chronic restraint stress decreases the number of astrocytes and induces apoptosis and ER stress in the amygdala, which are possible causes for psychiatric

  15. Influence of resveratrol on endoplasmic reticulum stress and expression of adipokines in adipose tissues/adipocytes induced by high-calorie diet or palmitic acid.

    Science.gov (United States)

    Chen, Li; Wang, Ting; Chen, Guanjun; Wang, Nuojin; Gui, Li; Dai, Fang; Fang, Zhaohui; Zhang, Qiu; Lu, Yunxia

    2017-03-01

    This study aimed to determine whether resveratrol treatment alleviates endoplasmic reticulum stress and changes the expression of adipokines in adipose tissues and cells. 8-week-old male C57BL/6 mice were fed a high-calorie diet (HCD group) or high-calorie diet supplemented with resveratrol (high-calorie diet  + resveratrol group) for 3 months. Insulin resistance, serum lipids and proinflammatory indices, the size and inflammatory cell infiltration in subcutaneous and visceral adipose tissues were analyzed. The gene expressions of endoplasmic reticulum stress, adipokines, and inflammatory cytokines were determined. The induced mature 3T3-L1 cells were pretreated with resveratrol and then palmitic acid, and the gene expressions of endoplasmic reticulum stress, adipokines, and inflammatory cytokines were determined. Subcutaneous and visceral adipose tissues in the high-calorie diet-fed mice exhibited adipocyte hypertrophy, inflammatory activation, and endoplasmic reticulum stress. Resveratrol alleviated high-calorie diet-induced insulin resistance and endoplasmic reticulum stress, increased expression of SIRT1, and reversed expression of adipokines in varying degrees in both subcutaneous and visceral adipose tissues. The effects of resveratrol on palmitic acid-treated adipocytes were similar to those shown in the tissues. Resveratrol treatment obviously reversed adipocyte hypertrophy and insulin resistance by attenuating endoplasmic reticulum stress and inflammation, thus increasing the expression of SIRT1 and inverting the expression of adipokines in vivo and in vitro.

  16. The Hypothermic Influence on CHOP and Ero1-α in an Endoplasmic Reticulum Stress Model of Cerebral Ischemia

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    Gagandip K. Poone

    2015-05-01

    Full Text Available Hypoxia induced endoplasmic reticulum stress causes accumulation of unfolded proteins in the endoplasmic reticulum and activates the unfolded protein response, resulting in apoptosis through CCAAT-enhancer-binding protein homologous protein (CHOP activation. In an in vitro and in vivo model of ischemic stroke, we investigated whether hypothermia regulates the unfolded protein response of CHOP and Endoplasmic reticulum oxidoreductin-α (Ero1-α, because Ero1-α is suggested to be a downstream CHOP target. The gene expression of CHOP and Ero1-α was measured using Quantitative-PCR (Q-PCR in rat hippocampi following global cerebral ischemia, and in hypoxic pheochromocytoma cells during normothermic (37 °C and hypothermic (31 °C conditions. As a result of ischemia, a significant increase in expression of CHOP and Ero1-α was observed after three, six and twelve hours of reperfusion following global ischemia. A stable increase in CHOP expression was observed throughout the time course (p < 0.01, p < 0.0001, whereas Ero1-α expression peaked at three to six hours (p < 0.0001. Induced hypothermia in hypoxia stressed PC12 cells resulted in a decreased expression of CHOP after three, six and twelve hours (p < 0.0001. On the contrary, the gene expression of Ero1-α increased as a result of hypothermia and peaked at twelve hours (p < 0.0001. Hypothermia attenuated the expression of CHOP, supporting that hypothermia suppress endoplasmic reticulum stress induced apoptosis in stroke. As hypothermia further induced up-regulation of Ero1-α, and since CHOP and Ero1-α showed differential regulation as a consequence of both disease (hypoxia and treatment (hypothermia, we conclude that they are regulated independently.

  17. Interaction between endoplasmic reticulum stress and caspase 8 activation in retrovirus MoMuLV-ts1-infected astrocytes.

    Science.gov (United States)

    Liu, Na; Scofield, Virginia L; Qiang, Wenan; Yan, Mingshan; Kuang, Xianghong; Wong, Paul K Y

    2006-05-10

    The murine retrovirus, MoMuLV-ts1, induces progressive paralysis and immune deficiency in FVB/N mice. We have reported previously that ts1 infection causes apoptosis in astrocytes via endoplasmic reticulum (ER) and mitochondrial stress (Liu, N., Kuang, X., Kim, H.T., Stoica, G., Qiang, W., Scofield, V.L., Wong, P.K.Y. Wong. 2004. Possible involvement of both endoplasmic reticulum- and mitochondria-dependent pathways in MoMuLV-ts1-induced apoptosis in astrocytes. J. NeuroVirol. 10, 189-198). In the present study, we show that caspase 8 activation in these cells is mediated through ER stress-associated elevation of death receptor DR5 and the C/EBP homologous protein (GADD153/CHOP), an ER stress-initiated transcription factor, rather than through TNFalpha and TNF-R1 interactions on the cell surface. Treatment with Z-IETD-FMK, a specific inhibitor of caspase 8 enzymatic activity, reduced ER stress by two mechanisms: by inhibiting caspase 8 activation, and by preventing cleavage of the ER-associated membrane protein BAP31 into BAP20, which exacerbates the ER stress response. These findings suggest that caspase 8- and ER stress-associated apoptotic pathways are linked in ts1-infected astrocytes.

  18. MEMS shear stress sensors for cardiovascular diagnostics.

    Science.gov (United States)

    Soundararajan, Gopikrishnan; Hsiai, Tzung K; DeMaio, Lucas; Chang, Michael; Chang, Stanley

    2004-01-01

    Coronary artery disease is the leading cause of morbidity and mortality in the industrialized nations. Both biochemical and biomechanical stimuli modulate the pathogenesis of coronary artery diseases. Shear stress acting on the lumen of blood vessels intimately modulates the biological activities of vascular endothelial cells (ECs). We hereby develop microelectro mechanical system (MEMS)-based sensors at the dimension comparable to a single EC to monitor realtime shear stress in fluidic channel. Our goal is to fabricate sensors for ex vivo or in vivo shear stress measurement at Reynolds number commonly encountered in human circulation. The MEMS sensors were designed based on the previously described heat transfer principles. The polysilicon was doped with phosphorous to render the sensing element a high resistivity at 2.5 KOmega. The development of backside wire bonding enabled the application for the vascular geometry. The small dimension (80x2 mum) and the gain amplitude at 71 KHz offered an entry point to measure shear stress with high spatial and temporal resolution.

  19. Cyclin-dependent kinase 5 contributes to endoplasmic reticulum stress induced podocyte apoptosis via promoting MEKK1 phosphorylation at Ser280 in diabetic nephropathy.

    Science.gov (United States)

    Zhang, Yue; Gao, Xiang; Chen, Shuanggang; Zhao, Min; Chen, Jing; Liu, Rui; Cheng, Shengyang; Qi, Mengyuan; Wang, Shuo; Liu, Wei

    2017-02-01

    Endoplasmic reticulum (ER) stress has been reported to be associated with podocyte apoptosis in diabetic nephropathy, but the mechanism of ER signaling in podocyte apoptosis hasn't been fully understood. Our previous studies have demonstrated that Cyclin-dependent kinase 5 (Cdk5) was associated with podocyte apoptosis in diabetic nephropathy. The present study was designed to examine whether and how Cdk5 activity plays a role in ER stress induced podocyte apoptosis in diabetic nephropathy. The results showed that along with induction of Cdk5 and apoptosis, GRP78 and its two sensors as well as CHOP and cleaved caspase-12 were induced in high glucose treated podocytes. These responses were attenuated by treated salubrinal. The ER stress inducer, tunicamycin, also up-regulated the kinase activity and protein expression of Cdk5 in podocytes accompanied with the increasing of GRP78. On the other hand, Cdk5 phosphorylates MEKK1 at Ser280 in tunicamycin treated podocytes, and together, they increase the JNK phosphorylation. Moreover, disruption of this pathway can decrease the podocyte apoptosis induced by tunicamycin. Therefore, our study proved that Cdk5 may play an important role in ER stress induced podocyte apoptosis through MEKK1/JNK pathway in diabetic nephropathy.

  20. Protective effects of endoplasmic reticulum stress preconditioning on hippocampal neurons in rats with status epilepticus

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    Yi ZHANG

    2014-12-01

    Full Text Available Objective To evaluate the protective effects of endoplasmic reticulum stress preconditioning induced by 2-deoxyglucose (2-DG on hippocampal neurons of rats with status epilepticus (SE and the possible mechanism.  Methods Ninety Sprague-Dawley (SD rats were randomly enrolled into preconditioning group (N = 30, SE group (N = 30 and control group (N = 30. Each group was divided into 6 subsets (N = 5 according to six time points (before seizure, 6 h, 12 h, 1 d, 2 d and 7 d after seizure. The preconditioning group was administered 2-DG intraperitoneally with a dose of 150 mg/kg for 7 days, and the lithium-pilocarpine induced SE rat model was established on both preconditioning group and SE group. The rats were sacrificed at the above six time points, and the brains were removed to make paraffin sections. Nissl staining was performed by toluidine blue to evaluate the hippocampal neuronal damage after seizure, and the number of survival neurons in hippocampal CA1 and CA3 regions of the rats were counted. Immunohistochemical staining was performed to detect the expressions of glucose regulated protein 78 (GRP78 and X-box binding protein 1 (XBP-1 in hippocampal CA3 region of the rats.  Results The number of survival neurons in preconditioning group was much more than that in SE group at 7 d after seizure (t = 5.353, P = 0.000, and was more obvious in CA1 region. There was no significant hippocampal neuronal damage in control group. The expressions of GRP78 and XBP-1 in CA3 region of hippocampus in SE group at 6 h after seizure were significantly higher than that in control group (P = 0.000, and then kept increasing until reaching the peak at 2 d (P = 0.000, for all. The expressions of GRP78 and XBP-1 in hippocampal CA3 region in preconditioning group were significantly higher than that in control group before seizure (P = 0.000, for all. The level of GRP78 maintained the highest at 24 h and 2 d after seizure (P = 0.000, for all, while the XBP-1 level

  1. 6-Shogaol induces apoptosis in human hepatocellular carcinoma cells and exhibits anti-tumor activity in vivo through endoplasmic reticulum stress.

    Directory of Open Access Journals (Sweden)

    Rong Hu

    Full Text Available 6-Shogaol is an active compound isolated from Ginger (Zingiber officinale Rosc. In this work, we demonstrated that 6-shogaol induces apoptosis in human hepatocellular carcinoma cells in relation to caspase activation and endoplasmic reticulum (ER stress signaling. Proteomic analysis revealed that ER stress was accompanied by 6-shogaol-induced apoptosis in hepatocellular carcinoma cells. 6-shogaol affected the ER stress signaling by regulating unfolded protein response (UPR sensor PERK and its downstream target eIF2α. However, the effect on the other two UPR sensors IRE1 and ATF6 was not obvious. In prolonged ER stress, 6-shogaol inhibited the phosphorylation of eIF2α and triggered apoptosis in SMMC-7721 cells. Salubrinal, an activator of the PERK/eIF2α pathway, strikingly enhanced the phosphorylation of eIF2α in SMMC-7721 cells with no toxicity. However, combined treatment with 6-shogaol and salubrinal resulted in significantly increase of apoptosis and dephosphorylation of eIF2α. Overexpression of eIF2α prevented 6-shogaol-mediated apoptosis in SMMC-7721 cells, whereas inhibition of eIF2α by small interfering RNA markedly enhanced 6-shogaol-mediated cell death. Furthermore, 6-shogaol-mediated inhibition of tumor growth of mouse SMMC-7721 xenograft was associated with induction of apoptosis, activation of caspase-3, and inactivation of eIF2α. Altogether our results indicate that the PERK/eIF2α pathway plays an important role in 6-shogaol-mediated ER stress and apoptosis in SMMC-7721 cells in vitro and in vivo.

  2. Hyperactivity of the Ero1α Oxidase Elicits Endoplasmic Reticulum Stress but No Broad Antioxidant Response

    Science.gov (United States)

    Hansen, Henning Gram; Schmidt, Jonas Damgård; Søltoft, Cecilie Lützen; Ramming, Thomas; Geertz-Hansen, Henrik Marcus; Christensen, Brian; Sørensen, Esben Skipper; Juncker, Agnieszka Sierakowska; Appenzeller-Herzog, Christian; Ellgaard, Lars

    2012-01-01

    Oxidizing equivalents for the process of oxidative protein folding in the endoplasmic reticulum (ER) of mammalian cells are mainly provided by the Ero1α oxidase. The molecular mechanisms that regulate Ero1α activity in order to harness its oxidative power are quite well understood. However, the overall cellular response to oxidative stress generated by Ero1α in the lumen of the mammalian ER is poorly characterized. Here we investigate the effects of overexpressing a hyperactive mutant (C104A/C131A) of Ero1α. We show that Ero1α hyperactivity leads to hyperoxidation of the ER oxidoreductase ERp57 and induces expression of two established unfolded protein response (UPR) targets, BiP (immunoglobulin-binding protein) and HERP (homocysteine-induced ER protein). These effects could be reverted or aggravated by N-acetylcysteine and buthionine sulfoximine, respectively. Because both agents manipulate the cellular glutathione redox buffer, we conclude that the observed effects of Ero1α-C104A/C131A overexpression are likely caused by an oxidative perturbation of the ER glutathione redox buffer. In accordance, we show that Ero1α hyperactivity affects cell viability when cellular glutathione levels are compromised. Using microarray analysis, we demonstrate that the cell reacts to the oxidative challenge caused by Ero1α hyperactivity by turning on the UPR. Moreover, this analysis allowed the identification of two new targets of the mammalian UPR, CRELD1 and c18orf45. Interestingly, a broad antioxidant response was not induced. Our findings suggest that the hyperoxidation generated by Ero1α-C104A/C131A is addressed in the ER lumen and is unlikely to exert oxidative injury throughout the cell. PMID:23027870

  3. Polyamine Depletion Attenuates Isoproterenol-Induced Hypertrophy and Endoplasmic Reticulum Stress in Cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Yan Lin

    2014-10-01

    Full Text Available Background/Aim: Polyamines (putrescine, spermidine and spermine play an essential role in cell growth, differentiation and apoptosis. Hypertrophy is accompanied by an increase in polyamine synthesis and endoplasmic reticulum stress (ERS in cardiomyocytes. The present study was undertaken to elucidate the molecular interactions between polyamines, ERS and cardiac hypertrophy. Methods: Myocardial hypertrophy was simulated by incubating cultured neonatal rat cardiomyocytes in 100 nM isoproterenol (ISO. Polyamine deletion was achieved using 0.5 mM difluoromethylornithine (DFMO. Hypertrophy was estimated using cell surface area measurements, total protein concentrations and atrial natriuretic peptide (ANP gene expression. Apoptosis was measured using flow cytometry and transmission electron microscopy. Expression of ornithine decarboxylase (ODC and spermidine/spermine N1-acetyltransferase (SSAT were analyzed via real-time PCR and Western blotting. Protein expression of ERS and apoptosis factors were analyzed using Western blotting. Results: DFMO (0.5 mM and 2 mM treatments significantly attenuated hypertrophy and apoptosis induced by ISO in cardiomyocytes. DFMO also decreased lactate dehydrogenase (LDH and malondialdehyde (MDA level in the culture medium. In addition, DFMO (0.5 mM down regulated the expression of ODC, glucose-regulated protein 78 (GRP78, C/EBP homologous protein (CHOP, cleaved caspase-12, and Bax and up regulated the expression of SSAT and Bcl-2. Finally, these changes were partly reversed by the addition of exogenous putrescine (0.5 mM. Conclusion: The data presented here suggest that polyamine depletion could inhibit cardiac hypertrophy and apoptosis, which is closely related to the ERS pathway.

  4. Expression levels of urotensin II are associated with endoplasmic reticulum stress in patients with severe preeclampsia.

    Science.gov (United States)

    He, W-Y; Chen, G-J; Lai, X; Wu, F; Tang, C-S; Zhang, A-H

    2016-02-01

    Hypertensive disorders in pregnancy remain a leading cause of maternal and perinatal mortality and morbidity. We aim to study urotensin II (UII) and its association with the markers of endoplasmic reticulum stress (ERS) in placentas of patients with severe preeclampsia (SPE). Thirty-three patients with hypertensive disorders in pregnancy and twenty-two healthy pregnant women designated as healthy controls were recruited. Expression levels of UII, UII receptor (GPR14) and the markers of ERS in placenta specimens of patients were performed. Plasma and urinary UII levels were measured by radioimmunoassay method. Our study showed that the plasma levels of UII in patients with hypertensive disorders during pregnancy were significantly higher than that of the healthy control group. However, the urinary levels of UII had no difference in two groups. The expression level of mRNA and protein of UII, CCAAT/enhancer-binding protein homologous protein (CHOP) and glucose regulation protein 78 in placentas of SPE was significantly increased. Immunohistochemical analyses show that the expression levels of UII and ERS markers were mainly located in the cytoplasm of placental trophoblastic cells. Moreover, expression level of UII mRNA and protein was positively correlated with that of the markers of ERS. The positive correlation between UII and ERS markers expression level also corresponded with the level of patient's systolic blood pressure and proteinuria. In conclusion, we first verify that expression of UII is associated with ERS in patients with SPE. Our results indicate that UII may trigger ERS in placental trophoblastic cells in patients with preeclampsia.

  5. Endoplasmic reticulum stress mediates the anti-inflammatory effect of ethyl pyruvate in endothelial cells.

    Directory of Open Access Journals (Sweden)

    Ge Wang

    Full Text Available Ethyl pyruvate (EP is a simple aliphatic ester of the metabolic intermediate pyruvate that has been demonstrated to be a potent anti-inflammatory agent in a variety of in vivo and in vitro model systems. However, the protective effects and mechanisms underlying the actions of EP against endothelial cell (EC inflammatory injury are not fully understood. Previous studies have confirmed that endoplasmic reticulum stress (ERS plays an important role in regulating the pathological process of EC inflammation. In this study, our aim was to explore the effects of EP on tumor necrosis factor-α (TNF-α-induced inflammatory injury in human umbilical vein endothelial cells (HUVECs and to explore the role of ERS in this process. TNF-α treatment not only significantly increased the adhesion of monocytes to HUVECs and inflammatory cytokine (sICAM1, sE-selectin, MCP-1 and IL-8 production in cell culture supernatants but it also increased ICAM and MMP9 protein expression in HUVECs. TNF-α also effectively increased the ERS-related molecules in HUVECs (GRP78, ATF4, caspase12 and p-PERK. EP treatment effectively reversed the effects of the TNF-α-induced adhesion of monocytes on HUVECs, inflammatory cytokines and ERS-related molecules. Furthermore, thapsigargin (THA, an ERS inducer attenuated the protective effects of EP against TNF-α-induced inflammatory injury and ERS. The PERK siRNA treatment not only inhibited ERS-related molecules but also mimicked the protective effects of EP to decrease TNF-α-induced inflammatory injury. In summary, we have demonstrated for the first time that EP can effectively reduce vascular endothelial inflammation and that this effect at least in part depends on the attenuation of ERS.

  6. Melatonin inhibits tunicamycin-induced endoplasmic reticulum stress and insulin resistance in skeletal muscle cells.

    Science.gov (United States)

    Quan, Xiaojuan; Wang, Juyan; Liang, Chunlian; Zheng, Huadong; Zhang, Lin

    2015-08-07

    The prevalence of type 2 diabetes mellitus (T2D) is increasing worldwide. Melatonin possesses various beneficial metabolic actions, decreased levels of which may accelerate T2D. Endoplasmic reticulum stress (ERS) has been linked to insulin resistance in multiple tissues, but the role of melatonin on ERS and insulin resistance in skeletal muscle has not yet been investigated. In this study, the results showed that tunicamycin decreased insulin-stimulated Akt phosphorylation, but promoted the phosphorylation of protein kinase R-like ER protein kinase (PERK) time-dependently in C2C12 cells. Consistently, ERS gene markers, including binding immunoglobulin protein (BIP)/glucose regulated protein 78 (GRP78) expression and the splicing of X box binding protein 1 (XBP-1), were activated by tunicamycin time-dependently. Interestingly, melatonin pretreatment reversed the elevated PERK phosphorylation, as well as the activation of Bip expression and XBP-1 splicing, and prevented the inhibitory effect of tunicamycin on Akt phosphorylation. In addition, the insulin-provoked glucose transport was reduced by tunicamycin, and then promoted by melatonin pretreatment. A strong phosphorylation of inositol-requiring enzyme 1 (IRE-1), c-JUN NH2-terminal kinase (JNK), and insulin receptor substrate 1 (IRS-1) serine, and simultaneously, a dramatic decrease of IRS-1 tyrosine phosphorylation were observed in the presence of tunicamycin, leading to a blockade of insulin signaling, which was reversed by melatonin pretreatment. Furthermore, luzindole pretreatment acted inversely with melatonin action on glucose uptake and insulin signaling. Therefore, these results demonstrated that melatonin pretreatment inhibited the activated role of tunicamycin on ERS and insulin resistance through melatonin receptor-mediated IRE-1/JNK/IRS-1 insulin signaling in skeletal muscle cells.

  7. Endoplasmic reticulum stress and membranous nephropathy%内质网应激与膜性肾病

    Institute of Scientific and Technical Information of China (English)

    李静

    2011-01-01

    Endoplasmic reticulum ( ER) is an intracellular compartment that plays a critical role in the processing, folding and assembling of newly synthesized proteins. A scress-induced impairment of ER membrane integrity can be injurious by causing leakage of calcium ions and other ER luminal components and interfering with protein transport to Golgi apparatus. This in tum initiates the unfolded protein response ( UPR) . an integrated intracellular signaling pathway that responds to ER stress. As a defense mechanism,UPR can protect the cells from being impaired by ER stress. Also, UPR can activate pathways of cell death in response to prolonged or severe ER stress. This review highlights the current knowledge of ER stress in membranous nephropathy.%内质网(endoplasmic reticulum,ER)是调节蛋白质合成、折叠及组装的重要场所.各种原因如ER中Ca2+缺乏均可引起ER功能紊乱,使蛋白质从ER向高尔基体的转运受阻[1],最终引发内质网应激(endoplasmic reticulum stress,ERS).细胞通过激活未折叠蛋白反应(the unfolded protein response,UPR)保护ERS引起损伤的细胞,强烈或持久的ERS又可启动UPR的促凋亡信号.肾病尤其是膜性肾病(membranous nephropathy,MN)的发生发展与ERS密切相关,文中主要阐述ERS在MN发病机制中的作用.

  8. Endurance exercise training ameliorates insulin resistance and reticulum stress in adipose and hepatic tissue in obese rats.

    Science.gov (United States)

    da Luz, Gabrielle; Frederico, Marisa J S; da Silva, Sabrina; Vitto, Marcelo F; Cesconetto, Patricia A; de Pinho, Ricardo A; Pauli, José R; Silva, Adelino S R; Cintra, Dennys E; Ropelle, Eduardo R; De Souza, Cláudio T

    2011-09-01

    Obesity-induced endoplasmatic reticulum (ER) stress has been demonstrated to underlie the induction of obesity-induced JNK and NF-κB activation inflammatory responses, and generation of peripheral insulin resistance. On the other hand, exercise has been used as a crucial tool in obese and diabetic patients, and may reduce inflammatory pathway stimulation. However, the ability of exercise training to reverse endoplasmatic reticulum stress in adipose and hepatic tissue in obesity has not been investigated in the literature. Here, we demonstrate that exercise training ameliorates ER stress and insulin resistance in DIO-induced rats. Rats were fed with standard rodent chow (3,948 kcal kg(-1)) or high-fat diet (5,358 kcal kg(-1)) for 2 months. After that rats were submitted to swimming training (1 h per day, 5 days for week with 5% overload of the body weight for 8 weeks). Samples from epididymal fat and liver were obtained and western blot analysis was performed. Our results showed that swimming protocol reduces pro-inflammatory molecules (JNK, IκB and NF-κB) in adipose and hepatic tissues. In addition, exercise leads to reduction in ER stress, by reducing PERK and eIF2α phosphorylation in these tissues. In parallel, an increase in insulin pathway signaling was observed, as confirmed by increases in IR, IRSs and Akt phosphorylation following exercise training in DIO rats. Thus, results suggest that exercise can reduce ER stress, improving insulin resistance in adipose and hepatic tissue.

  9. Stress-transfer characteristics of embedded fiber Bragg grating sensors

    Institute of Scientific and Technical Information of China (English)

    BAO Ji-long; CHEN Ying; ZHAO Hong-xia

    2005-01-01

    The shear lag theory is used to analyze the stress transfer from concrete matrix to FBG sensors based on that the FBG sensor and the concrete matrix are composite. The stress transfer formula and the coefficient are obtained. The experiments prove that the theoretical results of the stress transfer by the stress transfer formula are in well agreement with the experimental data.

  10. Progress in the unraveling of the endoplasmic reticulum stress/autophagy pathway and cancer: implications for future therapeutic approaches.

    Science.gov (United States)

    Schleicher, Stephen M; Moretti, Luigi; Varki, Vinod; Lu, Bo

    2010-06-01

    Given the inherent resistance to apoptosis that characterizes cancer, the targeting of alternative pathways is an attractive strategy to improve anti-tumor therapy. Endoplasmic reticulum (ER) stress, which is basally activated in many cancers, and the subsequent activation of autophagy represent novel cancer treatment targets. While these associated pathways are often protective and promote cell survival, when excessive, ER stress results in autophagic cell death. Therefore, depending on the circumstances, either inhibition or activation of ER stress and autophagy can improve cancer therapy. This review provides an update on how ER stress relates to autophagy, and how these associated pathways can serve dual functions to promote survival or cell death in cancer. Furthermore, it lays out a spectrum of potential pharmacological agents and combinatorial approaches that target these pathways to enhance tumor cell kill.

  11. Endoplasmic reticulum stress-induced resistance to doxorubicin is reversed by paeonol treatment in human hepatocellular carcinoma cells.

    Directory of Open Access Journals (Sweden)

    Lulu Fan

    Full Text Available BACKGROUND: Endoplasmic reticulum stress (ER stress is generally activated in solid tumors and results in tumor cell anti-apoptosis and drug resistance. Paeonol (Pae, 2-hydroxy-4-methoxyacetophenone, is a natural product extracted from the root of Paeonia Suffruticosa Andrew. Although Pae displays anti-neoplastic activity and increases the efficacy of chemotherapeutic drugs in various cell lines and in animal models, studies related to the effect of Pae on ER stress-induced resistance to chemotherapeutic agents in hepatocellular carcinoma (HCC are poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we investigated the effect of the endoplasmic reticulum (ER stress response during resistance of human hepatocellular carcinoma cells to doxorubicin. Treatment with the ER stress-inducer tunicamycin (TM before the addition of doxorubicin reduced the rate of apoptosis induced by doxorubicin. Interestingly, co-pretreatment with tunicamycin and Pae significantly increased apoptosis induced by doxorubicin. Furthermore, induction of ER stress resulted in increasing expression of COX-2 concomitant with inactivation of Akt and up-regulation of the pro-apoptotic transcription factor CHOP (GADD153 in HepG2 cells. These cellular changes in gene expression and Akt activation may be an important resistance mechanism against doxorubicin in hepatocellular carcinoma cells undergoing ER stress. However, co-pretreatment with tunicamycin and Pae decreased the expression of COX-2 and levels of activation of Akt as well as increasing the levels of CHOP in HCC cells. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that Pae reverses ER stress-induced resistance to doxorubicin in human hepatocellular carcinoma cells by targeting COX-2 mediated inactivation of PI3K/AKT/CHOP.

  12. Lipocalin 2, a new GADD153 target gene, as an apoptosis inducer of endoplasmic reticulum stress in lung cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Hsin, I-Lun; Hsiao, Yueh-Chieh [Institute of Medical and Molecular Toxicology, Chung Shan Medical University, Taichung 40201, Taiwan (China); Institute of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan (China); Wu, Ming-Fang [Division of Chest Medicine, Department of Internal Medicine, Chung Shan Medical University Hospital, Taichung 40201, Taiwan (China); School of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan (China); Jan, Ming-Shiou [Institute of Microbiology and Immunology, Chung Shan Medical University, Taichung 40201, Taiwan (China); Tang, Sheau-Chung; Lin, Yu-Wen [Institute of Medical and Molecular Toxicology, Chung Shan Medical University, Taichung 40201, Taiwan (China); Institute of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan (China); Hsu, Chung-Ping, E-mail: cliff@vghtc.com.tw [Department of Thoracic Surgery, Veterans General Hospital—Taichung, Taichung 40705, Taiwan (China); Department of Surgery, National Yang-Ming University School of Medicine and Taipei Veterans General Hospital, Taipei 11221, Taiwan (China); Ko, Jiunn-Liang, E-mail: jlko@csmu.edu.tw [Institute of Medical and Molecular Toxicology, Chung Shan Medical University, Taichung 40201, Taiwan (China); Institute of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan (China); Division of Chest Medicine, Department of Internal Medicine, Chung Shan Medical University Hospital, Taichung 40201, Taiwan (China)

    2012-09-15

    Endoplasmic reticulum (ER) stress is activated under severe cellular conditions. GADD153, a member of the C/EBP family, is an unfolded protein response (UPR) responsive transcription factor. Increased levels of lipocalin 2, an acute phase protein, have been found in several epithelial cancers. The aim of this study is to investigate the function of lipocalin 2 in lung cancer cells under ER stress. Treatment with thapsigargin, an ER stress activator, led to increases in cytotoxicity, ER stress, apoptosis, and lipocalin 2 expression in A549 cells. GADD153 silencing decreased lipocalin 2 expression in A549 cells. On chromatin immunoprecipitation assay, ER stress increased GADD153 DNA binding to lipocalin 2 promoter. Furthermore, silencing of lipocalin 2 mitigated ER stress-mediated apoptosis in A549 cells. Our findings demonstrated that lipocalin 2 is a new GADD153 target gene that mediates ER stress-induced apoptosis. Highlights: ► We demonstrate that Lipocalin 2 is a new GADD153 target gene. ► Lipocalin 2 mediates ER stress-induced apoptosis. ► ER stress-induced lipocalin 2 expression is calcium-independent in A549 cells. ► Lipocalin 2 dose not play a major role in ER stress-induced autophagy.

  13. TRAIL-Induced Caspase Activation Is a Prerequisite for Activation of the Endoplasmic Reticulum Stress-Induced Signal Transduction Pathways.

    Science.gov (United States)

    Lee, Dae-Hee; Sung, Ki Sa; Guo, Zong Sheng; Kwon, William Taehyung; Bartlett, David L; Oh, Sang Cheul; Kwon, Yong Tae; Lee, Yong J

    2016-05-01

    It is well known that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis can be initially triggered by surface death receptors (the extrinsic pathway) and subsequently amplified through mitochondrial dysfunction (the intrinsic pathway). However, little is known about signaling pathways activated by the TRAIL-induced endoplasmic reticulum (ER) stress response. In this study, we report that TRAIL-induced apoptosis is associated with the endoplasmic reticulum (ER) stress response. Human colorectal carcinoma HCT116 cells were treated with TRAIL and the ER stress-induced signal transduction pathway was investigated. During TRAIL treatment, expression of ER stress marker genes, in particular the BiP (binding immunoglobulin protein) gene, was increased and activation of the PERK (PKR-like ER kinase)-eIF2α (eukaryotic initiation factor 2α)-ATF4 (activating transcription factor 4)-CHOP (CCAAT-enhancer-binding protein homologous protein) apoptotic signal transduction pathway occurred. Experimental data from use of a siRNA (small interfering RNA) technique, caspase inhibitor, and caspase-3-deficient cell line revealed that TRAIL-induced caspase activation is a prerequisite for the TRAIL-induced ER stress response. TRAIL-induced ER stress was triggered by caspase-8-mediated cleavage of BAP31 (B cell receptor-associated protein 31). The involvement of the proapoptotic PERK-CHOP pathway in TRAIL-induced apoptosis was verified by using a PERK knockout (PERK(-/-)) mouse embryo fibroblast (MEF) cell line and a CHOP(-/-) MEF cell line. These results suggest that TRAIL-induced the activation of ER stress response plays a role in TRAIL-induced apoptotic death.

  14. Respiratory metabolism and calorie restriction relieve persistent endoplasmic reticulum stress induced by calcium shortage in yeast

    DEFF Research Database (Denmark)

    Busti, Stefano; Mapelli, Valeria; Tripodi, Farida

    2016-01-01

    Calcium homeostasis is crucial to eukaryotic cell survival. By acting as an enzyme cofactor and a second messenger in several signal transduction pathways, the calcium ion controls many essential biological processes. Inside the endoplasmic reticulum (ER) calcium concentration is carefully regula...

  15. Hypothyroidism minimizes the effects of acute hepatic failure caused by endoplasmic reticulum stress and redox environment alterations in rats.

    Science.gov (United States)

    Blas-Valdivia, Vanessa; Cano-Europa, Edgar; Martinez-Perez, Yoalli; Lezama-Palacios, Ruth; Franco-Colin, Margarita; Ortiz-Butron, Rocio

    2015-10-01

    The aim of this study was to investigate if a protective effect from hypothyroidism in acute liver failure resulted from reduced endoplasmic reticulum stress and changes to the redox environment. Twenty male Sprague-Dawley rats were divided in four groups: (1) euthyroid (sham surgery), (2) hypothyroid, (3) euthyroid (sham surgery)+thioacetamide and (4) hypothyroid+thioacetamide. Hypothyroidism was confirmed two weeks after thyroidectomy, and thioacetamide (TAA) (400mg/kg, ip) was administrated to the appropriate groups for three days with supportive therapy. Grades of encephalopathy in all animals were determined using behavioral tests. Animals were decapitated and their blood was obtained to assess liver function. The liver was dissected: the left lobe was used for histology and the right lobe was frozen for biochemical assays. Body weight, rectal temperature and T4 concentration were lower in hypothyroid groups. When measurements of oxidative stress markers, redox environment, γ-glutamylcysteine synthetase and glutathione-S-transferase were determined, we observed that hypothyroid animals with TAA compensated better with oxidative damage than euthyroid animals treated with TAA. Furthermore, we measured reduced expressions of GADD34, caspase-12 and GRP78 and subsequently less hypothyroidism-induced cellular damage in hypothyroid animals. We conclude that hypothyroidism protects against hepatic damage caused by TAA because it reduces endoplasmic reticulum stress and changes to the redox environment.

  16. Caspase-4 directly activates caspase-9 in endoplasmic reticulum stress-induced apoptosis in SH-SY5Y cells.

    Science.gov (United States)

    Yamamuro, Akiko; Kishino, Takashi; Ohshima, Yu; Yoshioka, Yasuhiro; Kimura, Tomoki; Kasai, Atsushi; Maeda, Sadaaki

    2011-01-01

    The present study investigated the function of caspase-4 in endoplasmic reticulum (ER) stress-induced apoptosis in human neuronal cell line SH-SY5Y. Tunicamycin, which is known to induce ER stress, activated both caspase-9 and caspase-4, and the activation of caspase-4 preceded that of caspase-9. The caspase-4 inhibitor LEVD-CHO suppressed both the apoptosis and caspase-9 activation. In addition, human recombinant active caspase-4 cleaved wild type and D330A mutant substituted Asp-330 for alanine of human recombinant procaspase-9, but did not cleave D315A mutant substituted Asp-315 for alanine. These results suggest that caspase-4 directly activates caspase-9 by the processing of procaspase-9 at Asp-315 in ER stress-induced neuronal apoptosis.

  17. Ethanol extract of Brazilian red propolis induces apoptosis in human breast cancer MCF-7 cells through endoplasmic reticulum stress.

    Science.gov (United States)

    Kamiya, Tetsuro; Nishihara, Hiroko; Hara, Hirokazu; Adachi, Tetsuo

    2012-11-07

    Propolis, a natural product collected from plants by honey bees, is commonly used in folk medicines. Endoplasmic reticulum (ER) stress is known to induce apoptosis through the induction of CCAAT/enhancer-binding protein homologous protein (CHOP). Here, we investigated whether ethanol extracts of propolis and caffeic acid phenethyl ester (CAPE) induce apoptosis, mitochondrial dysfunction, and ER stress in human breast cancer MCF-7 cells and human fibroblasts. Among several ethanol extracts of propolis and CAPE, Brazilian red propolis (BRP) significantly reduced MCF-7 cell viability through the induction of mitochondrial dysfunction, caspase-3 activity, and DNA fragmentation but did not affect those of fibroblasts. Moreover, treatment with BRP significantly induced CHOP expression in MCF-7 cells compared to fibroblasts. Further, pretreatment with a chemical chaperone, 4-phenylbutyric acid, suppressed BRP-triggered MCF-7 cell death. Overall, we revealed that an ethanol extract of BRP induces MCF-7 cell apoptosis through, at least in part, ER stress-related signaling.

  18. 内质网应激与缺血后处理的心肌保护%Endoplasmic reticulum stress and the cardioprotection of ischemic postconditioning

    Institute of Scientific and Technical Information of China (English)

    杨海燕; 刘新伟

    2010-01-01

    Endoplasmic reticulum stress is the cell adaptation reaction for a variety of noxious stimulation. But excessive endoplasmic reticulum stress can induce apoptosis and further lead to myocardium injury in the process of ischemia-reperfusion. Ischemic postconditioning is a phenomenon of endogenous protection which attenuates reperfusion injury by several signal transduction pathways, and regulation of endoplasmic reticulum stress is an important aspect. This review will discuss the cardioprotection mechanisms of ischemic postconditioning from endoplasmic reticulum stress.%内质网应激(endoplasmic reticulum stress,ERS)是细胞对各种伤害性刺激的适应性反应.在心肌缺血/再灌注(ischemia/reperfusion,I/R)过程中,过度的ERS引起心肌细胞凋亡导致心肌损伤.缺血后处理(ischemic postconditioning,I-postC)是心肌对抗I/R损伤的内源性保护现象,可通过多条信号转导途径发挥心肌保护作用,对ERS的调节是其重要方面.现将从ERS的角度探讨I-postC的心肌保护机制.

  19. The specialized pro-resolving lipid mediator maresin 1 protects hepatocytes from lipotoxic and hypoxia-induced endoplasmic reticulum stress.

    Science.gov (United States)

    Rius, Bibiana; Duran-Güell, Marta; Flores-Costa, Roger; López-Vicario, Cristina; Lopategi, Aritz; Alcaraz-Quiles, José; Casulleras, Mireia; Lozano, Juan José; Titos, Esther; Clària, Joan

    2017-08-02

    Endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR) are hallmarks of nonalcoholic fatty liver disease (NAFLD), which is the hepatic manifestation of the metabolic syndrome associated with obesity. The specialized pro-resolving lipid mediator maresin 1 (MaR1) preserves tissue homeostasis by exerting cytoprotective actions, dampening inflammation, and expediting its timely resolution. Here, we explored whether MaR1 protects liver cells from lipotoxic and hypoxia-induced ER stress. Mice were rendered obese by high-fat diet feeding, and experiments were performed in primary hepatocytes, Kupffer cells, and precision-cut liver slices (PCLSs). Palmitate-induced lipotoxicity increased ER stress and altered autophagy in hepatocytes, effects that were prevented by MaR1. MaR1 protected hepatocytes against lipotoxicity-induced apoptosis by activating the UPR prosurvival mechanisms and preventing the excessive up-regulation of proapoptotic pathways. Protective MaR1 effects were also seen in hepatocytes challenged with hypoxia and TNF-α-induced cell death. High-throughput microRNA (miRNA) sequencing revealed that MaR1 actions were associated with specific miRNA signatures targeting both protein folding and apoptosis. MaR1 also prevented lipotoxic-triggered ER stress and hypoxia-induced inflammation in PCLSs and enhanced Kupffer cell phagocytic capacity. Together, these findings describe the ability of MaR1 to oppose ER stress in liver cells under conditions frequently encountered in NAFLD.-Rius, B., Duran-Güell, M., Flores-Costa, R., López-Vicario, C., Lopategi, A., Alcaraz-Quiles, J., Casulleras, M., Lozano, J. J., Titos, E., Clària, J. The specialized pro-resolving lipid mediator maresin 1 protects hepatocytes from lipotoxic and hypoxia-induced endoplasmic reticulum stress. © FASEB.

  20. Copper induces hepatocyte injury due to the endoplasmic reticulum stress in cultured cells and patients with Wilson disease.

    Science.gov (United States)

    Oe, Shinji; Miyagawa, Koichiro; Honma, Yuichi; Harada, Masaru

    2016-09-10

    Copper is an essential trace element, however, excess copper is harmful to human health. Excess copper-derived oxidants contribute to the progression of Wilson disease, and oxidative stress induces accumulation of abnormal proteins. It is known that the endoplasmic reticulum (ER) plays an important role in proper protein folding, and that accumulation of misfolded proteins disturbs ER homeostasis resulting in ER stress. However, copper-induced ER homeostasis disturbance has not been fully clarified. We treated human hepatoma cell line (Huh7) and immortalized-human hepatocyte cell line (OUMS29) with copper and chemical chaperones, including 4-phenylbutyrate and ursodeoxycholic acid. We examined copper-induced oxidative stress, ER stress and apoptosis by immunofluorescence microscopy and immunoblot analyses. Furthermore, we examined the effects of copper on carcinogenesis. Excess copper induced not only oxidative stress but also ER stress. Furthermore, excess copper induced DNA damage and reduced cell proliferation. Chemical chaperones reduced this copper-induced hepatotoxicity. Excess copper induced hepatotoxicity via ER stress. We also confirmed the abnormality of ultra-structure of the ER of hepatocytes in patients with Wilson disease. These findings show that ER stress plays a pivotal role in Wilson disease, and suggests that chemical chaperones may have beneficial effects in the treatment of Wilson disease.

  1. Involvement of Endoplasmic Reticulum Stress, Autophagy, and Apoptosis in Advanced Glycation End Products-Induced Glomerular Mesangial Cell Injury

    Science.gov (United States)

    Chiang, Chih-Kang; Wang, Ching-Chia; Lu, Tien-Fong; Huang, Kuo-How; Sheu, Meei-Ling; Liu, Shing-Hwa; Hung, Kuan-Yu

    2016-01-01

    Advanced glycation end-products (AGEs)-induced mesangial cell death is one of major causes of glomerulus dysfunction in diabetic nephropathy. Both endoplasmic reticulum (ER) stress and autophagy are adaptive responses in cells under environmental stress and participate in the renal diseases. The role of ER stress and autophagy in AGEs-induced mesangial cell death is still unclear. Here, we investigated the effect and mechanism of AGEs on glomerular mesangial cells. AGEs dose-dependently decreased mesangial cell viability and induced cell apoptosis. AGEs also induced ER stress signals in a time- and dose-dependent manner. Inhibition of ER stress with 4-phenylbutyric acid effectively inhibited the activation of eIF2α and CHOP signals and reversed AGEs-induced cell apoptosis. AGEs also activated LC-3 cleavage, increased Atg5 expression, and decreased p62 expression, which indicated the autophagy induction in mesangial cells. Inhibition of autophagy by Atg5 siRNAs transfection aggravated AGEs-induced mesangial cell apoptosis. Moreover, ER stress inhibition by 4-phenylbutyric acid significantly reversed AGEs-induced autophagy, but autophagy inhibition did not influence the AGEs-induced ER stress-related signals activation. These results suggest that AGEs induce mesangial cell apoptosis via an ER stress-triggered signaling pathway. Atg5-dependent autophagy plays a protective role. These findings may offer a new strategy against AGEs toxicity in the kidney. PMID:27665710

  2. Airborne particulate matter selectively activates endoplasmic reticulum stress response in the lung and liver tissues.

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    Laing, Suzette; Wang, Guohui; Briazova, Tamara; Zhang, Chunbin; Wang, Aixia; Zheng, Ze; Gow, Alexander; Chen, Alex F; Rajagopalan, Sanjay; Chen, Lung Chi; Sun, Qinghua; Zhang, Kezhong

    2010-10-01

    Recent studies have suggested a link between inhaled particulate matter (PM) exposure and increased mortality and morbidity associated with pulmonary and cardiovascular diseases. However, a precise understanding of the biological mechanism underlying PM-associated toxicity and pathogenesis remains elusive. Here, we investigated the impact of PM exposure in intracellular stress signaling pathways with animal models and cultured cells. Inhalation exposure of the mice to environmentally relevant fine particulate matter (aerodynamic diameter liver tissues as well as in the mouse macrophage cell line RAW264.7. Ambient PM(2.5) exposure activates double-strand RNA-activated protein kinase-like ER kinase (PERK), leading to phosphorylation of translation initiation factor eIF2α and induction of C/EBP homologous transcription factor CHOP/GADD153. Activation of PERK-mediated UPR pathway relies on the production of reactive oxygen species (ROS) and is critical for PM(2.5)-induced apoptosis. Furthermore, PM(2.5) exposure can activate ER stress sensor IRE1α, but it decreases the activity of IRE1α in splicing the mRNA encoding the UPR trans-activator X-box binding protein 1 (XBP1). Together, our study suggests that PM(2.5) exposure differentially activates the UPR branches, leading to ER stress-induced apoptosis through the PERK-eIF2α-CHOP UPR branch. This work provides novel insights into the cellular and molecular basis by which ambient PM(2.5) exposure elicits its cytotoxic effects that may be related to air pollution-associated pathogenesis.

  3. Metformin prevents endoplasmic reticulum stress-induced apoptosis through AMPK-PI3K-c-Jun NH2 pathway

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    Jung, T.W.; Lee, M.W.; Lee, Y.-J.; Kim, S.M.

    2012-01-01

    Type 2 diabetes mellitus is thought to be partially associated with endoplasmic reticulum (ER) stress toxicity on pancreatic beta cells and the result of decreased insulin synthesis and secretion. In this study, we showed that a well-known insulin sensitizer, metformin, directly protects against dysfunction and death of ER stress-induced NIT-1 cells (a mouse pancreatic beta cell line) via AMP-activated protein kinase (AMPK) and phosphatidylinositol-3 (PI3) kinase activation. We also showed that exposure of NIT-1 cells to metformin (5mM) increases cellular resistance against ER stress-induced NIT-1 cell dysfunction and death. AMPK and PI3 kinase inhibitors abolished the effect of metformin on cell function and death. Metformin-mediated protective effects on ER stress-induced apoptosis were not a result of an unfolded protein response or the induced inhibitors of apoptotic proteins. In addition, we showed that exposure of ER stressed-induced NIT-1 cells to metformin decreases the phosphorylation of c-Jun NH(2) terminal kinase (JNK). These data suggest that metformin is an important determinant of ER stress-induced apoptosis in NIT-1 cells and may have implications for ER stress-mediated pancreatic beta cell destruction via regulation of the AMPK-PI3 kinase-JNK pathway.

  4. Upregulation of the SERCA-type Ca2+ pump activity in response to endoplasmic reticulum stress in PC12 cells

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    Frandsen Aase

    2001-04-01

    Full Text Available Abstract Background Ca2+-ATPases of endoplasmic reticulum (SERCAs are responsible for maintenance of the micro- to millimolar Ca2+ ion concentrations within the endoplasmic reticulum (ER of eukaryotic cells. This intralumenal Ca2+ storage is important for the generation of Ca2+ signals as well as for the correct folding and posttranslational processing of proteins entering ER after synthesis. ER perturbations such as depletion of Ca2+ or abolishing the oxidative potential, inhibition of glycosylation, or block of secretory pathway, activate the Unfolded Protein Response, consisting of an upregulation of a number of ER-resident chaperones/stress proteins in an effort to boost the impaired folding capacity. Results We show here that in PC12 cells, depletion of ER Ca2+ by EGTA, as well as inhibition of disulphide bridge formation within the ER by dithiotreitol or inhibition of N-glycosylation by tunicamycin, led to a 2- to 3-fold increase of the SERCA-mediated 45Ca2+ transport to microsomes isolated from cells exposed to these stress agents. The time course of this response corresponded to that for transcriptional upregulation of ER stress proteins, as well as to the increase in the SERCA2b mRNA, as we recently observed in an independent study. Conclusions These findings provide the first functional evidence for the increase of SERCA pumping capacity in cells subjected to the ER stress. Since at least three different and unrelated mechanisms of eliciting the ER stress response were found to cause this functional upregulation of Ca2+ transport into the ER, these results support the existence of a coupling between the induction of the UPR pathway in general, and the regulation of expression of at least one of the SERCA pump isoforms.

  5. Endoplasmic Reticulum Stress and Bipolar Disorder - Almost Forgotten Therapeutic Drug Targets in the Unfolded Protein Response Pathway Revisited.

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    Bengesser, Susanne A; Fuchs, Robert; Lackner, Nina; Birner, Armin; Reininghaus, Bernd; Meier-Allard, Nathalie; Stracke, Anika; Kapfhammer, Hans-Peter; Reininghaus, Eva Z; Wallner-Liebmann, Sandra

    2016-01-01

    Bipolar Disorder (BD) is characterized by recurring mood swings, which are not completely understood yet. So far, it is an accepted theory that multiple factors contribute to pathogenesis of BD according to the vulnerability-stressmodel. This model combines on the one hand biological predisposing vulnerability, and on the other hand several chronic and acute stressful negative events as underlying mechanisms of BD. Recently, ER (Endoplasmic Reticulum) stress reached the spotlight of BD research again. The expression of the chaperone BiP (syn. GRP78/glucose-regulated protein, 78kDa), which is highly expressed in the Endoplasmic Reticulum (ER), is upregulated by different kinds of mood stabilizers. These results implied that the ER, an organelle which is prone towards different kinds of cellular stress, might be involved in the pathophysiology of BD. This hypothesis was further strengthened by hypothesis driven genetic association studies, which showed significant association of BiP promotor polymorphisms with BD. Also other ER-stress associated genes like XBP1 (X-box binding protein 1) or GRP94 (glucose-regulated protein, 94kDa, synonym for heat shock protein HSP90B1) were recently linked to BD in hypothesis driven gene association studies. In addition to the proteins mentioned before, our review focuses on further UPR (Unfolded Protein Response) related proteins associated with BD and raises the hypothesis that ER-stress may represent a common interface between BD and obesity which is overrepresented in BD patients. Finally, members of the UPR pathway are discussed as putative targets for mood stabilizers.

  6. A Phytophthora sojae effector suppresses endoplasmic reticulum stress-mediated immunity by stabilizing plant Binding immunoglobulin Proteins

    Science.gov (United States)

    Jing, Maofeng; Guo, Baodian; Li, Haiyang; Yang, Bo; Wang, Haonan; Kong, Guanghui; Zhao, Yao; Xu, Huawei; Wang, Yan; Ye, Wenwu; Dong, Suomeng; Qiao, Yongli; Tyler, Brett M.; Ma, Wenbo; Wang, Yuanchao

    2016-01-01

    Phytophthora pathogens secrete an array of specific effector proteins to manipulate host innate immunity to promote pathogen colonization. However, little is known about the host targets of effectors and the specific mechanisms by which effectors increase susceptibility. Here we report that the soybean pathogen Phytophthora sojae uses an essential effector PsAvh262 to stabilize endoplasmic reticulum (ER)-luminal binding immunoglobulin proteins (BiPs), which act as negative regulators of plant resistance to Phytophthora. By stabilizing BiPs, PsAvh262 suppresses ER stress-triggered cell death and facilitates Phytophthora infection. The direct targeting of ER stress regulators may represent a common mechanism of host manipulation by microbes. PMID:27256489

  7. Hydrogen sulfide regulates vascular endoplasmic reticulum stress in apolipoprotein E knockout mice

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhi-fang; ZHAO Bin; TANG Xiu-ying; LI Wei; ZHU Lu-lu; TANG Chao-shu; DU Jun-bao; JIN Hong-fang

    2011-01-01

    Background Atherosclerosis is an important cardiovascular disease,becoming a major and increasing health problem in developed countries.However,the possible underlying mechanisms were not completely clear.In 2009,our research group first discovered that hydrogen sulfide (H2S) as a novel gastrotransmitter played an important anti-atherosclerotic role.The study was designed to examine the regulatory effect of hydrogen sulfide (H2S) on endoplasmic reticulum stress (ERS) in apolipoprotein E knockout (apoE(-/-)) mice fed a Western type diet.Methods C57BL/6 mice and homozygous apoE(-/-) mice were fed a Western type diet.C57BL/6 mice were injected intraperitoneally with normal saline (5 ml/kg per day) as control group.The apoE+ mice were treated with the same dose of normal saline as the apoE(-/-) group,injected intraperitoneally with sodium hydrosulfide (NaHS,an H2S donor,56μmol/kg per day) as the apoE(-/-)+NaHS group and injected intraperitoneally with DL-propargylglycine (PPG,a cystathionine-y-lyase inhibitor,50 mg/kg,per day) as the apoE/ +PPG group.After 10 weeks,the mice were sacrificed and the plasma lipids were detected.Sections of aortic root from these animals were examined for atherosclerotic lesions by HE and oil red O staining.The aortic ultrastructure and microstructure were analyzed with the help of light and electronic microscope.Glucose-regulated protein 78 (GRP78),caspase-12,copper-andzinc-containing superoxide dismutase (Cu/ZnSOD) and Mn-containing superoxide dismutase (MnSOD) protein expression in aortic tissues were detected with immunohistochemistry.The level of intracellular reactive oxygen species (ROS) were measured by using a commercial assay kit.Results Compared with control mice,apoE(-/-) mice showed increased plasma levels of total cholesterol (TC),triglyceride (TG) and low density lipoprotein (LDL),decreased high density lipoprotein (HDL),increased aortic plaque size,destroyed ultra-structure of aortic tissue,and increased expression of GRP

  8. Fibroblast growth factor 21 reverses suppression of adiponectin expression via inhibiting endoplasmic reticulum stress in adipose tissue of obese mice.

    Science.gov (United States)

    Guo, Qinyue; Xu, Lin; Liu, Jiali; Li, Huixia; Sun, Hongzhi; Wu, Shufang; Zhou, Bo

    2017-02-01

    Fibroblast growth factor 21 (FGF21) has recently emerged as a novel endocrine hormone involved in the regulation of glucose and lipid metabolism. However, the exact mechanisms whereby FGF21 mediates insulin sensitivity remain not fully understood. In the present study, FGF21was administrated in high-fat diet-induced obese mice and tunicamycin-induced 3T3-L1 adipocytes, and metabolic parameters, endoplasmic reticulum (ER) stress indicators, and insulin signaling molecular were assessed by Western blotting. The administration of FGF21 in obese mice reduced body weight, blood glucose and serum insulin, and increased insulin sensitivity, resulting in alleviation of insulin resistance. Meanwhile, FGF21 treatment reversed suppression of adiponectin expression and restored insulin signaling via inhibiting ER stress in adipose tissue of obese mice. Additionally, suppression of ER stress via the ER stress inhibitor tauroursodeoxycholic acid increased adiponectin expression and improved insulin resistance in obese mice and in tunicamycin-induced adipocytes. In conclusion, our results showed that the administration of FGF21 reversed suppression of adiponectin expression and restored insulin signaling via inhibiting ER stress under the condition of insulin resistance, demonstrating the causative role of ER stress in downregulating adiponectin levels.

  9. Inhibition of soluble epoxide hydrolase attenuates hepatic fibrosis and endoplasmic reticulum stress induced by carbon tetrachloride in mice

    Science.gov (United States)

    Harris, Todd R.; Bettaieb, Ahmed; Kodani, Sean; Dong, Hua; Myers, Richard; Chiamvimonvat, Nipavan; Haj, Fawaz G.; Hammock, Bruce D.

    2015-01-01

    Liver fibrosis is a pathological condition in which chronic inflammation and changes to the extracellular matrix lead to alterations in hepatic tissue architecture and functional degradation of the liver. Inhibitors of the enzyme soluble epoxide hydrolase (sEH) reduce fibrosis in the heart, pancreas and kidney in several disease models. In this study, we assess the effect of sEH inhibition on the development of fibrosis in a carbon tetrachloride (CCl4)-induced mouse model by monitoring changes in the inflammatory response, matrix remolding and endoplasmic reticulum stress. The sEH inhibitor 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU) was administered in drinking water. Collagen deposition in the liver was increased five-fold in the CCl4-treated group, and this was returned to control levels by TPPU treatment. Hepatic expression of Col1a2 and 3a1 mRNA was increased over fifteen-fold in the CCl4-treated group relative to the control group, and this increase was reduced by 50% by TPPU treatment. Endoplasmic reticulum (ER) stress observed in the livers of CCl4-treated animals was attenuated by TPPU treatment. In order to support the hypothesis that TPPU is acting to reduce the hepatic fibrosis and ER stress through its action as a sEH inhibitor we used a second sEH inhibitor, trans-4-{4-[3-(4-trifluoromethoxy-phenyl)-ureido]-cyclohexyloxy}-benzoic acid (t-TUCB), and sEH null mice. Taken together, these data indicate that the sEH may play an important role in the development of hepatic fibrosis induced by CCl4, presumably by reducing endogenous fatty acid epoxide chemical mediators acting to reduce ER stress. PMID:25827057

  10. Apoptosis and necrosis induced by novel realgar quantum dots in human endometrial cancer cells via endoplasmic reticulum stress signaling pathway

    Directory of Open Access Journals (Sweden)

    Wang H

    2015-08-01

    Full Text Available Huan Wang,1–3 Zhengyun Liu,4 Ying Gou,3 Yu Qin,4 Yaze Xu,5 Jie Liu,4 Jin-Zhu Wu6 1Research Center for Medicine and Biology, 2Guizhou Provincial College-based Key Lab for Tumor Prevention and Treatment with Distinctive Medicines, 3Department of Microbiology, 4Key Lab for Basic Pharmacology of Ministry of Education, 5Pharmacy School, Zunyi Medical College, Zunyi, 6Department of Chemistry, School of Science, Harbin Institute of Technology, Harbin, People’s Republic of China Abstract: Realgar (AS4S4 has been used in traditional medicines for malignancy, but the poor water solubility is still a major hindrance to its clinical use. Realgar quantum dots (RQDs were therefore synthesized with improved water solubility and bioavailability. Human endometrial cancer JEC cells were exposed to various concentrations of RQDs to evaluate their anticancer effects and to explore mechanisms by the MTT assay, transmission electron microscopy (TEM, flow cytometry, real-time reverse transcriptase polymerase chain reaction (RT-PCR and Western blot analysis. Results revealed that the highest photoluminescence quantum yield of the prepared RQDs was up to approximately 70%, with the average size of 5.48 nm. RQDs induced antiproliferative activity against JEC cells in a concentration-dependent manner. In light microscopy and TEM examinations, RQDs induced vacuolization and endoplasmic reticulum (ER dilation in JEC cells in a concentration-dependent manner. ER stress by RQDs were further confirmed by increased expression of GADD153 and GRP78 at both mRNA and protein levels. ER stress further led to JEC cell apoptosis and necrosis, as evidenced by flow cytometry and mitochondrial membrane potential detection. Our findings demonstrated that the newly synthesized RQDs were effective against human endometrial cancer cells. The underlying mechanism appears to be, at least partly, due to ER stress leading to apoptotic cell death and necrosis. Keywords: realgar, quantum dots

  11. RAGE deficiency alleviates aortic valve calcification in ApoE(-/-) mice via the inhibition of endoplasmic reticulum stress.

    Science.gov (United States)

    Wang, Bo; Cai, Zhejun; Liu, Baoqing; Liu, Zongtao; Zhou, Xianming; Dong, Nianguo; Li, Fei

    2017-03-01

    Receptor for advanced glycation end products (RAGE) and endoplasmic reticulum (ER) stress have been shown to be involved in calcific aortic valve disease (CAVD). However, the association between RAGE and ER stress remains unknown in the pathogenesis of CAVD. The current study aims to test the hypothesis that RAGE deficiency alleviates aortic valve calcification via the inhibition of ER stress. Up-regulation of RAGE and ER stress markers in calcified human aortic valves were confirmed by immunoblotting. Aortic valve calcification was evaluated in atherosclerotic prone ApoE(-/-) mice or in mice with dual deficiencies of ApoE and RAGE (ApoE(-/-)RAGE(-/-)) fed with high cholesterol diet for 24weeks. Echocardiography and histological examination show that genetic deficiency of RAGE attenuates aortic valve calcification in ApoE(-/-) mice. Meanwhile, RAGE deficiency inhibited the osteogenic signaling and ER stress activation as well as suppressed macrophage infiltration in vivo. Cultured human aortic valve interstitial cells (AVICs) were treated with high molecular group box 1 protein (HMGB1) as in vitro model. We found that HMGB1 induced osteoblastic differentiation and calcification through RAGE/ER stress. Furthermore, Sox9 up-regulation and intranuclear translocation mediated the pro-osteogenic effect of HMGB1 on AVICs. RAGE or ER stress knockdown reduced the up-regulation of monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-α (TNF-α) in human AVICs exposed to HMGB1.These novel findings demonstrate that RAGE deficiency protects against aortic valve calcification in high cholesterol diet-fed ApoE(-/-) mice via inhibition of ER stress. HMGB1 induces AVIC osteoblastic differentiation and calcification through RAGE/ER stress/Sox9 pathway. Copyright © 2016. Published by Elsevier B.V.

  12. Role of miR-181a-5p and endoplasmic reticulum stress in the regulation of myogenic differentiation.

    Science.gov (United States)

    Wei, Yingying; Tao, Xuelian; Xu, Huaming; Chen, Yan; Zhu, Li; Tang, Guoqing; Li, Mingzhou; Jiang, Anan; Shuai, Surong; Ma, Jideng; Jin, Long; Wen, Anxiang; Wang, Qin; Zhu, Guangxiang; Xie, Meng; Wu, Jiayun; He, Tao; Jiang, Yanzhi; Li, Xuewei

    2016-10-30

    Accumulating evidence has indicated that microRNAs (miRNAs) and endoplasmic reticulum (ER) stress play critical roles in myoblast differentiation. However, the regulation roles of miRNAs and ER stress in myogenic differentiation have not been fully revealed and need to be further studied. Here, we discovered that the expression levels of miR-181a-5p were strongly upregulated during C2C12 cell differentiation. miR-181a-5p overexpression promoted ER stress and differentiation of C2C12 cells, which was accompanied by increasing expression levels of marker genes related to ER stress-mediated apoptosis and myogenic differentiation. Opposite results were observed after inhibition of the miR-181a-5p expression. The gain- and loss-of-function experiments on C2C12 cells showed that miR-181a-5p affected the development of muscle fiber type, but had no significant influence on C2C12 cell proliferation. In the ER-stressed C2C12 cells induced by thapsigargin (Tg), the expression levels of both miR-181a-5p and marker genes related to ER stress and myogenesis were upregulated. In the ER-stressed C2C12 cells and porcine muscle fibroblast (PMF) cells pretreated with Tg, we found that miR-181a-5p targeted glucose-regulated protein, 78kDa/binding immunoglobulin protein (GRP78/BIP), and influenced cell apoptosis. In conclusion, these results indicate that miR-181a-5p and ER stress have positive synergistic effects on myogenic differentiation by increasing the expression levels of myogenic differentiation key genes and activating the ER stress-mediated apoptosis signaling pathway.

  13. Thymoquinone prevents endoplasmic reticulum stress and mitochondria-induced apoptosis in a rat model of partial hepatic warm ischemia reperfusion.

    Science.gov (United States)

    Bouhlel, Ahlem; Ben Mosbah, Ismail; Hadj Abdallah, Najet; Ribault, Catherine; Viel, Roselyne; Mannaï, Saber; Corlu, Anne; Ben Abdennebi, Hassen

    2017-10-01

    This study was undertaken to evaluate the protective effect of thymoquinone (TQ), the bioactive compound of Nigella sativa seeds, against warm ischemia-reperfusion (I/R) injury in liver. Rats were given an oral administration of a vehicle solution (sham group) or TQ at the appropriate dose (10, 20, 30 and 40mg/kg) for ten days consecutively. Following, they were subjected to 60min of partial hepatic ischemia followed by 24h of reperfusion. .Transaminase activities, histopathological changes, TNFα and antioxidant parameters were evaluated. Also, endoplasmic reticulum (ER) stress, mitochondrial damage and apoptosis were studied. In addition, ERK and P38 phosphorylation was determined by Western blot technique. We found that TQ at 30mg/kg is the effective dose to protect rat liver against I/R injury. Moreover, 30mg/kg of TQ prevented histological damages, inflammation and oxidative stress. Interestingly, it decreased the expression of ER stress parameters including GRP78, CHOP and caspase-12. In parallel, it improved mitochondrial function and attenuated the expression of apoptotic parameters. Furthermore, TQ significantly enhanced ERK and P38 phosphorylation. In conclusion, we demonstrated the potential of TQ to protect the rat liver against I/R injury through the prevention of ER stress and mitochondrial dysfunction. These effects implicate the prevention of oxidative stress. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  14. Crocin and Quercetin protect HCT116 and HEK293 cells from Zearalenone-induced apoptosis by reducing endoplasmic reticulum stress.

    Science.gov (United States)

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

    2015-11-01

    Mycotoxins are considered to be significant contaminants of food and animal feed. Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium in cereals and agricultural products. ZEN has been shown to be cytotoxic, genotoxic, and mutagenic in different cell types. In the present study, we investigated the involvement of endoplasmic reticulum (ER) stress in ZEN-mediated toxicity in human intestine (HCT116) and kidney (HEK293) cells and evaluated the effects of the two common dietary compounds Quercetin (QUER) and Crocin (CRO). We show that ZEN treatment induces ER stress and activates the unfolded protein response (UPR) as evidenced by XBP1 mRNA splicing and upregulation of GRP78, ATF4, GADD34, PDIA6, and CHOP. Activation of the ER stress response is associated with activation of the mitochondrial pathway of apoptosis. This apoptotic process is characterized by an increase in ROS generation and lipid peroxidation, a loss of mitochondrial transmembrane potential (ΔΨm), and an activation of caspases and DNA damages. We also demonstrate that the antioxidant properties of QUER and CRO help to prevent ER stress and reduce ZEN-induced apoptosis in HCT116 and HEK293 cells. Our results suggest that antioxidant molecule might be helpful to prevent ZEN-induced ER stress and toxicity.

  15. Oxalicumone A, a new dihydrothiophene-condensed sulfur chromone induces apoptosis in leukemia cells through endoplasmic reticulum stress pathway.

    Science.gov (United States)

    Wang, Jie; Wang, Qiao-Li; Nong, Xu-Hua; Zhang, Xiao-Yong; Xu, Xin-Ya; Qi, Shu-Hua; Wang, Yi-Fei

    2016-07-15

    Oxalicumone A (POA1), a novel dihydrothiophene-condensed sulfur chromone isolated from the marine fungus Penicillium oxalicum SCSGAF 0023, showed cytotoxicity against several cancer cells previously. In this study, its anti-cancer activity and underlying mechanism of this action were investigated in leukemia cells like KG-1a, HL60, U937, and K562. The results showed that POA1 inhibited dose-/time-dependently cell growth and induced apoptosis in leukemia cells. Also, POA1 caused cleavages of caspase-3, 8, 9 and PARP1, loss of mitochondrial membrane potential, up-regulations of phosphorylated p38 and JNK, and activation of endoplasmic reticulum stress (ER stress). Furthermore, 4-PBA (an ER stress inhibitor) but not SP600125 and SB203580 (JNK and p38 inhibitor, respectively) could largely inhibit POA1-induced growth suppression. Additionally, 4-PBA obstructed mitochondrial depolarization and cleavage of PARP1. These data suggested that ER stress pathway might be an important mediator in POA1-induced apoptosis. In conclusion, POA1 may have antitumor effects in leukemia cells through the induction of ER stress pathway. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Saturated lipids decrease mitofusin 2 leading to endoplasmic reticulum stress activation and insulin resistance in hypothalamic cells.

    Science.gov (United States)

    Diaz, Brenda; Fuentes-Mera, Lizeth; Tovar, Armando; Montiel, Teresa; Massieu, Lourdes; Martínez-Rodríguez, Herminia Guadalupe; Camacho, Alberto

    2015-11-19

    Endoplasmic reticulum (ER) and mitochondria dysfunction contribute to insulin resistance generation during obesity and diabetes. ER and mitochondria interact through Mitofusin 2 (MTF2), which anchors in the outer mitochondrial and ER membranes regulating energy metabolism. Ablation of MTF2 leads to ER stress activation and insulin resistance. Here we determine whether lipotoxic insult induced by saturated lipids decreases MTF2 expression leading to ER stress response in hypothalamus and its effects on insulin sensitivity using in vitro and in vivo models. We found that lipotoxic stimulation induced by palmitic acid, but not the monounsaturated palmitoleic acid, decreases MTF2 protein levels in hypothalamic mHypoA-CLU192 cells. Also, palmitic acid incubation activates ER stress response evidenced by increase in the protein levels of GRP78/BIP marker at later stage than MTF2 downregulation. Additionally, we found that MTF2 alterations induced by palmitic, but not palmitoleic, stimulation exacerbate insulin resistance in hypothalamic cells. Insulin resistance induced by palmitic acid is prevented by pre-incubation of the anti-inflammatory and the ER stress release reagents, sodium salicylate and 4 phenylbutirate, respectively. Finally, we demonstrated that lipotoxic insult induced by high fat feeding to mice decreases MTF2 proteins levels in arcuate nucleus of hypothalamus. Our data indicate that saturated lipids modulate MTF2 expression in hypothalamus coordinating the ER stress response and the susceptibility to insulin resistance.

  17. Hepatic overexpression of SIRT1 in mice attenuates endoplasmic reticulum stress and insulin resistance in the liver

    Science.gov (United States)

    Li, Yu; Xu, Shanqin; Giles, Amber; Nakamura, Kazuto; Lee, Jong Woo; Hou, Xiuyun; Donmez, Gizem; Li, Ji; Luo, Zhijun; Walsh, Kenneth; Guarente, Leonard; Zang, Mengwei

    2011-01-01

    Endoplasmic reticulum (ER) stress has been implicated in the pathophysiology of human type 2 diabetes (T2DM). Although SIRT1 has a therapeutic effect on metabolic deterioration in T2DM, the precise mechanisms by which SIRT1 improves insulin resistance remain unclear. Here, we demonstrate that adenovirus-mediated overexpression of SIRT1 in the liver of diet-induced insulin-resistant low-density lipoprotein receptor-deficient mice and of genetically obese ob/ob mice attenuates hepatic steatosis and ameliorates systemic insulin resistance. These beneficial effects were associated with decreased mammalian target of rapamycin complex 1 (mTORC1) activity, inhibited the unfolded protein response (UPR), and enhanced insulin receptor signaling in the liver, leading to decreased hepatic gluconeogenesis and improved glucose tolerance. The tunicamycin-induced splicing of X-box binding protein-1 and expression of GRP78 and CHOP were reduced by resveratrol in cultured cells in a SIRT1-dependent manner. Conversely, SIRT1-deficient mouse embryonic fibroblasts challenged with tunicamycin exhibited markedly increased mTORC1 activity and impaired ER homeostasi and insulin signaling. These effects were abolished by mTORC1 inhibition by rapamycin in human HepG2 cells. These studies indicate that SIRT1 serves as a negative regulator of UPR signaling in T2DM and that SIRT1 attenuates hepatic steatosis, ameliorates insulin resistance, and restores glucose homeostasis, largely through the inhibition of mTORC1 and ER stress.—Li, Y., Xu, S., Giles, A., Nakamura, K., Lee, J. W., Hou, X., Donmez, G., Li, J., Luo, Z., Walsh, K., Guarente, L., Zang, M. Hepatic overexpression of SIRT1 in mice attenuates endoplasmic reticulum stress and insulin resistance in the liver. PMID:21321189

  18. Towards Mental Stress Detection Using Wearable Physiological Sensors

    NARCIS (Netherlands)

    Wijsman, J.L.P; Grundlehner, Bernard; Liu, Hao; Liu, H.; Hermens, Hermanus J.; Penders, Julien

    2011-01-01

    Early mental stress detection can prevent many stress related health problems. This study aimed at using a wearable sensor system to measure physiological signals and detect mental stress. Three different stress conditions were presented to a healthy subject group. During the procedure, ECG,

  19. Towards Mental Stress Detection Using Wearable Physiological Sensors

    NARCIS (Netherlands)

    Wijsman, Jacqueline; Grundlehner, Bernard; Liu, Hao; Hermens, Hermie; Penders, Julien

    2011-01-01

    Early mental stress detection can prevent many stress related health problems. This study aimed at using a wearable sensor system to measure physiological signals and detect mental stress. Three different stress conditions were presented to a healthy subject group. During the procedure, ECG, respira

  20. Polymer-based stress sensor with integrated readout

    DEFF Research Database (Denmark)

    Thaysen, Jacob; Yalcinkaya, Arda Deniz; Vettiger, P.

    2002-01-01

    We present a polymer-based mechanical sensor with an integrated strain sensor element. Conventionally, silicon has been used as a piezoresistive material due to its high gauge factor and thereby high sensitivity to strain changes in the sensor. By using the fact that the polymer SU-8 [1] is much...... softer than silicon and that a gold resistor is easily incorporated in SU-8, we have proven that a SU-8-based cantilever sensor is almost as sensitive to stress changes as the silicon piezoresistive cantilever. First, the surface stress sensing principle is discussed, from which it can be shown...... that the SU-8-based sensor is nearly as sensitive as the silicon based mechanical sensor. We hereafter demonstrate the chip fabrication technology of such a sensor, which includes multiple SU-8 and gold layer deposition. The SU-8-based mechanical sensor is finally characterized with respect to sensitivity...

  1. Hydrogen sulfide inhibits formaldehyde-induced endoplasmic reticulum stress in PC12 cells by upregulation of SIRT-1.

    Directory of Open Access Journals (Sweden)

    Xiang Li

    Full Text Available BACKGROUND: Formaldehyde (FA, a well-known environmental pollutant, has been classified as a neurotoxic molecule. Our recent data demonstrate that hydrogen sulfide (H2S, the third gaseous transmitter, has a protective effect on the neurotoxicity of FA. However, the exact mechanisms underlying this protection remain largely unknown. Endoplasmic reticulum (ER stress has been implicated in the neurotoxicity of FA. Silent mating type information regulator 2 homolog 1 (SIRT-1, a histone deacetylases, has various biological activities, including the extension of lifespan, the modulation of ER stress, and the neuroprotective action. OBJECTIVE: We hypothesize that the protection of H2S against FA-induced neurotoxicity involves in inhibiting ER stress by upregulation of SIRT-1. The present study attempted to investigate the protective effect of H2S on FA-induced ER stress in PC12 cells and the contribution of SIRT-1 to the protection of H2S against FA-induced injuries, including ER stress, cytotoxicity and apoptosis. PRINCIPAL FINDINGS: We found that exogenous application of sodium hydrosulfide (NaHS; an H2S donor significantly attenuated FA-induced ER stress responses, including the upregulated levels of glucose-regulated protein 78, C/EBP homologous protein, and cleaved caspase-12 expression. We showed that NaHS upregulates the expression of SIRT-1 in PC12 cells. Moreover, the protective effects of H2S on FA-elicited ER stress, cytotoxicity and apoptosis were reversed by Sirtinol, a specific inhibitor of SIRT-1. CONCLUSION/SIGNIFICANCE: These data indicate that H2S exerts its protection against the neurotoxicity of FA through overcoming ER stress via upregulation of SIRT-1. Our findings provide novel insights into the protective mechanisms of H2S against FA-induced neurotoxicity.

  2. The effect of chronic ozone exposure on the activation of endoplasmic reticulum stress and apoptosis in rat hippocampus

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    Erika Rodríguez-Martínez

    2016-10-01

    Full Text Available The chronic exposure to low doses of ozone, like in environmental pollution, leads to a state of oxidative stress, which has been proposed to contribute to neurodegenerative disorders, including Alzheimer's disease. It induces an increase of calcium in the endoplasmic reticulum (ER, which produces ER stress. On the other hand, different studies show that, in diseases such as Alzheimer’s, there exist disturbances in protein folding where ER plays an important role. The objective of this study was to evaluate the state of chronic oxidative stress on ER stress and its relationship with apoptotic death in the hippocampus of rats exposed to low doses of ozone. We used 108 male Wistar rats randomly divided into five groups. The groups received one of the following treatments: 1 Control (air, 2 Ozone (O3 7 days, 3 O3 15 days, 4 O3 30 days, 5 O3 60 days, and 6 O3 90 days. Two hours after each treatment, the animals were sacrificed and the hippocampus was extracted. Afterwards, the tissue was processed for western blot and immunohistochemistry using the following antibodies: ATF6, GRP8 and caspase 12. It was also performed TUNEL assay and electronic microscopy. Our results show an increase in ATF6, GRP78 and caspase 12 as well as ER ultrastructural alterations and an increase of TUNEL positive cells after 60 and 90 days of exposure to ozone. With the obtained results, we can conclude that oxidative stress induced by chronic exposure to low doses of ozone leads to ER stress. ER stress activates ATF6 inducing the increase of GRP78 in the cytoplasm, which leads to the increase in the nuclear translocation of ATF6. Finally, the translocation creates a vicious cycle that, together with the activation of the cascade for apoptotic cell death, contributes to the maintenance of ER stress. These events potentially contribute in the neurodegeneration processes in diseases like Alzheimer’s Disease.

  3. Endothelin-1 induces endoplasmic reticulum stress by activating the PLC-IP(3) pathway: implications for placental pathophysiology in preeclampsia.

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    Jain, Arjun; Olovsson, Matts; Burton, Graham J; Yung, Hong-wa

    2012-06-01

    Recent evidence implicates placental endoplasmic reticulum (ER) stress in the pathophysiological characteristics of preeclampsia. Herein, we investigate whether endothelin (ET)-1, which induces Ca(2+) release from the ER, can induce placental ER stress. Loss of ER Ca(2+) homeostasis impairs post-translational modification of proteins, triggering ER stress-response pathways. IHC confirmed the presence of both ET-1 and its receptors in the syncytiotrophoblast. Protein levels and immunoreactivity of ET-1 and the endothelin B receptor (ETBR) were increased in preeclamptic samples compared with normotensive controls. JEG-3 and BeWo choriocarcinoma cells treated with ET-1 displayed an increase in ER stress markers. ET-1 induced phospho-activation of the ETBR. Treating cells with BQ788, an ETBR antagonist, or small-interfering RNA knockdown of the receptor inhibited induction of ER stress. ET-1 also stimulated p-phospholipase C (PLC)γ1 levels. By using inhibitors of PLC activation, U73122, and the inositol 1,4,5-triphosphate (IP(3)) receptor, xestospongin-C, we demonstrated that ET-1 induces ER stress via the PLC-IP(3) pathway. Furthermore, ET-1 levels increased in the syncytiotrophoblast of explants from normal placentas after hypoxia-reoxygenation in vitro. Conditioned medium from hypoxia-reoxygenation explants also contained higher ET-1 levels, which induced ER stress in JEG-3 cells that was abolished by an ET-1-neutralizing antibody. Collectively, the data show that ET-1 induced ER stress in trophoblasts via the ETBR and initiation of signaling through the PLC-IP(3) pathway, with the potential for autocrine stimulation.

  4. Chemical chaperones reduce ionizing radiation-induced endoplasmic reticulum stress and cell death in IEC-6 cells

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    Lee, Eun Sang; Lee, Hae-June; Lee, Yoon-Jin [Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Jeong, Jae-Hoon [Division of Radiotherapy, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Kang, Seongman [Division of Life Sciences, Korea University, Seoul 136-701 (Korea, Republic of); Lim, Young-Bin, E-mail: yblim@kirams.re.kr [Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of)

    2014-07-25

    Highlights: • UPR activation precedes caspase activation in irradiated IEC-6 cells. • Chemical ER stress inducers radiosensitize IEC-6 cells. • siRNAs that targeted ER stress responses ameliorate IR-induced cell death. • Chemical chaperons prevent cell death in irradiated IEC-6 cells. - Abstract: Radiotherapy, which is one of the most effective approaches to the treatment of various cancers, plays an important role in malignant cell eradication in the pelvic area and abdomen. However, it also generates some degree of intestinal injury. Apoptosis in the intestinal epithelium is the primary pathological factor that initiates radiation-induced intestinal injury, but the mechanism by which ionizing radiation (IR) induces apoptosis in the intestinal epithelium is not clearly understood. Recently, IR has been shown to induce endoplasmic reticulum (ER) stress, thereby activating the unfolded protein response (UPR) signaling pathway in intestinal epithelial cells. However, the consequences of the IR-induced activation of the UPR signaling pathway on radiosensitivity in intestinal epithelial cells remain to be determined. In this study, we investigated the role of ER stress responses in IR-induced intestinal epithelial cell death. We show that chemical ER stress inducers, such as tunicamycin or thapsigargin, enhanced IR-induced caspase 3 activation and DNA fragmentation in intestinal epithelial cells. Knockdown of Xbp1 or Atf6 with small interfering RNA inhibited IR-induced caspase 3 activation. Treatment with chemical chaperones prevented ER stress and subsequent apoptosis in IR-exposed intestinal epithelial cells. Our results suggest a pro-apoptotic role of ER stress in IR-exposed intestinal epithelial cells. Furthermore, inhibiting ER stress may be an effective strategy to prevent IR-induced intestinal injury.

  5. Anandamide-induced endoplasmic reticulum stress and apoptosis are mediated by oxidative stress in non-melanoma skin cancer: Receptor-independent endocannabinoid signaling.

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    Soliman, Eman; Van Dross, Rukiyah

    2016-11-01

    Endocannabinoids are neuromodulatory lipids that regulate central and peripheral physiological functions. Endocannabinoids have emerged as effective antitumor drugs due to their ability to induce apoptosis in various cancer studies. The G-protein coupled cannabinoid receptors (CB1 and CB2) and the TRPV1 ion channel were reported to mediate the antiproliferative activity of endocannabinoids. However, receptor-independent effects also account for their activity. Our previous studies showed that the antiproliferative activity of anandamide (AEA) was regulated by cyclooxygenase-2 (COX-2) via induction of endoplasmic reticulum (ER) stress. We also determined that AEA induced oxidative stress. However, the role of oxidative stress, the cannabinoid receptors, and TRPV1 in AEA-induced ER stress-apoptosis was unclear. Therefore, the current study examines the role of oxidative stress in ER stress-apoptosis and investigates whether this effect is modulated by CB1, CB2, or TRPV1. In non-melanoma skin cancer (NMSC) cells, AEA reduced the total intracellular level of glutathione and induced oxidative stress. To evaluate the importance of oxidative stress in AEA-induced cell death, the antioxidants, N-acetylcysteine (NAC) and Trolox, were utilized. Each antioxidant ameliorated the antiproliferative effect of AEA. Furthermore, Trolox inhibited AEA-induced CHOP10 expression and caspase 3 activity, indicating that oxidative stress was required for AEA-induced ER stress-apoptosis. On the other hand, selective blockade of CB1, CB2, and TRPV1 did not inhibit AEA-induced oxidative stress or ER stress-apoptosis. These findings suggest that AEA-induced ER stress-apoptosis in NMSC cells is mediated by oxidative stress through a receptor-independent mechanism. Hence, receptor-independent AEA signaling pathways may be targeted to eliminate NMSC. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  6. Licochalcone A-Induced Human Bladder Cancer T24 Cells Apoptosis Triggered by Mitochondria Dysfunction and Endoplasmic Reticulum Stress

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    Xuan Yuan

    2013-01-01

    Full Text Available Licochalcone A (LCA, a licorice chalconoid, is considered to be a bioactive agent with chemopreventive potential. This study investigated the mechanisms involved in LCA-induced apoptosis in human bladder cancer T24 cells. LCA significantly inhibited cells proliferation, increased reactive oxygen species (ROS levels, and caused T24 cells apoptosis. Moreover, LCA induced mitochondrial dysfunction, caspase-3 activation, and poly-ADP-ribose polymerase (PARP cleavage, which displayed features of mitochondria-dependent apoptotic signals. Besides, exposure of T24 cells to LCA triggered endoplasmic reticulum (ER stress; as indicated by the enhancement in 78 kDa glucose-regulated protein (GRP 78, growth arrest and DNA damage-inducible gene 153/C/EBP homology protein (GADD153/CHOP expression, ER stress-dependent apoptosis is caused by the activation of ER-specific caspase-12. All the findings from our study suggest that LCA initiates mitochondrial ROS generation and induces oxidative stress that consequently causes T24 cell apoptosis via the mitochondria-dependent and the ER stress-triggered signaling pathways.

  7. Inhibition of homocysteine-induced endoplasmic reticulum stress and endothelial cell damage by l-serine and glycine.

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    Sim, Woo-Cheol; Han, Inhoi; Lee, Wonseok; Choi, You-Jin; Lee, Kang-Yo; Kim, Dong Gwang; Jung, Seung-Hwan; Oh, Seon-Hee; Lee, Byung-Hoon

    2016-08-01

    Hyperhomocysteinemia is an independent risk factor for several cardiovascular diseases. The use of vitamins to modulate homocysteine metabolism substantially lowers the risk by reducing plasma homocysteine levels. In this study, we evaluated the effects of l-serine and related amino acids on homocysteine-induced endoplasmic reticulum (ER) stress and endothelial cell damage using EA.hy926 human endothelial cells. Homocysteine treatment decreased cell viability and increased apoptosis, which were reversed by cotreatment with l-serine. l-Serine inhibited homocysteine-induced ER stress as verified by decreased glucose-regulated protein 78kDa (GRP78) and C/EBP homologous protein (CHOP) expression as well as X-box binding protein 1 (xbp1) mRNA splicing. The effects of l-serine on homocysteine-induced ER stress are not attributed to intracellular homocysteine metabolism, but instead to decreased homocysteine uptake. Glycine exerted effects on homocysteine-induced ER stress, apoptosis, and cell viability that were comparable to those of l-serine. Although glycine did not affect homocysteine uptake or export, coincubation of homocysteine with glycine for 24h reduced the intracellular concentration of homocysteine. Taken together, l-serine and glycine cause homocysteine-induced endothelial cell damage by reducing the level of intracellular homocysteine. l-Serine acts by competitively inhibiting homocysteine uptake in the cells. However, the mechanism(s) by which glycine lowers homocysteine levels are unclear.

  8. Loss of Oca2 disrupts the unfolded protein response and increases resistance to endoplasmic reticulum stress in melanocytes.

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    Cheng, Tsing; Orlow, Seth J; Manga, Prashiela

    2013-11-01

    Accumulation of proteins in the endoplasmic reticulum (ER) typically induces stress and initiates the unfolded protein response (UPR) to facilitate recovery. If homeostasis is not restored, apoptosis is induced. However, adaptation to chronic UPR activation can increase resistance to subsequent acute ER stress. We therefore investigated adaptive mechanisms in Oculocutaneous albinism type 2 (Oca2)-null melanocytes where UPR signaling is arrested despite continued tyrosinase accumulation leading to resistance to the chemical ER stressor thapsigargin. Although thapsigargin triggers UPR activation, instead of Perk-mediated phosphorylation of eIF2α, in Oca2-null melanocytes, eIF2α was rapidly dephosphorylated upon treatment. Dephosphorylation was mediated by the Gadd34-PP1α phosphatase complex. Gadd34-complex inhibition blocked eIF2α dephosphorylation and significantly increased Oca2-null melanocyte sensitivity to thapsigargin. Thus, Oca2-null melanocytes adapt to acute ER stress by disruption of pro-apoptotic Perk signaling, which promotes cell survival. This is the first study to demonstrate rapid eIF2α dephosphorylation as an adaptive mechanism to ER stress.

  9. Yiqi Huoxue Recipe Improves Heart Function through Inhibiting Apoptosis Related to Endoplasmic Reticulum Stress in Myocardial Infarction Model of Rats

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    Li-Xia Lou

    2014-01-01

    Full Text Available Objective. To explore the mechanism of cardioprotective effects of Chinese medicine, Yiqi Huoxue recipe, in rats with myocardial infarction- (MI- induced heart failure. Methods. Male Sprague-Dawley rats underwent left anterior descending artery (LAD ligation or sham operation. The surviving MI rats were divided randomly into three groups: MI (5 mL/kg/d NS by gavage, MI + Metoprolol Tartrate (MT (12 mg/kg/d MT by gavage, and MI + Yiqi Huoxue (5 mL/kg recipe by gavage. And the sham operation rats were given 5 mL/kg/d normal saline. Treatments were given on the day following surgery for 4 weeks. Then rats were detected for heart structure and function by transthoracic echocardiography. Apoptosis in heart tissues was detected by TUNEL staining. To determine whether the endoplasmic reticulum (ER stress response pathway is included in the cardioprotective function of the recipe, ER stress related proteins such as GRP78 and caspase-12 were examined. Results. Yiqi Huoxue recipe attenuated heart function injury, reversed histopathological damage, alleviated myocardial apoptosis and inhibited ER stress in MI rats. Conclusion. All the results suggest that Yiqi Huoxue recipe improves the injured heart function maybe through inhibition of ER stress response pathway, which is a promising target in therapy for heart failure.

  10. Endoplasmic Reticulum Stress and Unfolded Protein Response in Atm-Deficient Thymocytes and Thymic Lymphoma Cells Are Attributable to Oxidative Stress

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    Mingshan Yan

    2008-02-01

    Full Text Available Both oxidative stress and endoplasmic reticulum (ER stress have been implicated in carcinogenesis. It is well documented that cells deficient in the ataxia-telangiectasia mutated (ATM gene undergo oxidative stress, which is critically involved in thymic lymphomagenesis in Atm-/- mice. Here we demonstrate that undifferentiated Atm-/- thymocytes show signs of ER stress and of the unfolded protein response (UPR. Using two-dimensional (2-D gel electrophoresis and mass spectrometry (MS analysis, we identified 22 differentially expressed proteins, including the ER stress marker glucose-regulated protein 78 (GRP78, in Atm-/- thymocytes and in Atm-/- thymic lymphoma cells relative to Atm+/+ thymocytes. The phosphorylated α subunit of eukaryotic translation initiation factor 2 (p-eIF2α, a UPR marker, was also increased in Atm-/- thymocytes. Cells of the ATL-1 line, which were derived from an Atm-/- mouse thymic lymphoma, were more sensitive to the ER stress inducer tunicamycin than were Atm+/+ thymic leukemia ASL-1 cells. Notably, treatment with hydrogen peroxide duplicated the effects of ATM deficiency in cultured thymocytes, and treatment with the novel cell-permeable thiol antioxidant N-acetylcysteine amide (AD4 reduced elevated p-eIF2α levels in thymocytes of Atm-/- mice. Thus, we propose that ER stress and the UPR are secondary to oxidative stress in Atm-/- thymocytes.

  11. TBHQ Alleviated Endoplasmic Reticulum Stress-Apoptosis and Oxidative Stress by PERK-Nrf2 Crosstalk in Methamphetamine-Induced Chronic Pulmonary Toxicity

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    Gu, Yu-Han; Liu, Ming; Bai, Yang; Liang, Li-Ye; Wang, Huai-Liang

    2017-01-01

    Methamphetamine (MA) leads to cardiac and pulmonary toxicity expressed as increases in inflammatory responses and oxidative stress. However, some interactions may exist between oxidative stress and endoplasmic reticulum stress (ERS). The current study is designed to investigate if both oxidative stress and ERS are involved in MA-induced chronic pulmonary toxicity and if antioxidant tertiary butylhydroquinone (TBHQ) alleviated ERS-apoptosis and oxidative stress by PERK-Nrf2 crosstalk. In this study, the rats were randomly divided into control group, MA-treated group (MA), and MA plus TBHQ-treated group (MA + TBHQ). Chronic exposure to MA resulted in slower growth of weight and pulmonary toxicity of the rats by increasing the pulmonary arterial pressure, promoting the hypertrophy of right ventricle and the remodeling of pulmonary arteries. MA inhibited the Nrf2-mediated antioxidative stress by downregulation of Nrf2, GCS, and HO-1 and upregulation of SOD2. MA increased GRP78 to induce ERS. Overexpression and phosphorylation of PERK rapidly phosphorylated eIF2α, increased ATF4, CHOP, bax, caspase 3, and caspase 12, and decreased bcl-2. These changes can be reversed by antioxidant TBHQ through upregulating expression of Nrf2. The above results indicated that TBHQ can alleviate MA-induced oxidative stress which can accelerate ERS to initiate PERK-dependent apoptosis and that PERK/Nrf2 is likely to be the key crosstalk between oxidative stress and ERS in MA-induced chronic pulmonary toxicity. PMID:28303170

  12. TBHQ Alleviated Endoplasmic Reticulum Stress-Apoptosis and Oxidative Stress by PERK-Nrf2 Crosstalk in Methamphetamine-Induced Chronic Pulmonary Toxicity

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    Yun Wang

    2017-01-01

    Full Text Available Methamphetamine (MA leads to cardiac and pulmonary toxicity expressed as increases in inflammatory responses and oxidative stress. However, some interactions may exist between oxidative stress and endoplasmic reticulum stress (ERS. The current study is designed to investigate if both oxidative stress and ERS are involved in MA-induced chronic pulmonary toxicity and if antioxidant tertiary butylhydroquinone (TBHQ alleviated ERS-apoptosis and oxidative stress by PERK-Nrf2 crosstalk. In this study, the rats were randomly divided into control group, MA-treated group (MA, and MA plus TBHQ-treated group (MA + TBHQ. Chronic exposure to MA resulted in slower growth of weight and pulmonary toxicity of the rats by increasing the pulmonary arterial pressure, promoting the hypertrophy of right ventricle and the remodeling of pulmonary arteries. MA inhibited the Nrf2-mediated antioxidative stress by downregulation of Nrf2, GCS, and HO-1 and upregulation of SOD2. MA increased GRP78 to induce ERS. Overexpression and phosphorylation of PERK rapidly phosphorylated eIF2α, increased ATF4, CHOP, bax, caspase 3, and caspase 12, and decreased bcl-2. These changes can be reversed by antioxidant TBHQ through upregulating expression of Nrf2. The above results indicated that TBHQ can alleviate MA-induced oxidative stress which can accelerate ERS to initiate PERK-dependent apoptosis and that PERK/Nrf2 is likely to be the key crosstalk between oxidative stress and ERS in MA-induced chronic pulmonary toxicity.

  13. A novel transcription factor, ERD15 (Early Responsive to Dehydration 15), connects endoplasmic reticulum stress with an osmotic stress-induced cell death signal.

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    Alves, Murilo S; Reis, Pedro A B; Dadalto, Silvana P; Faria, Jerusa A Q A; Fontes, Elizabeth P B; Fietto, Luciano G

    2011-06-03

    As in all other eukaryotic organisms, endoplasmic reticulum (ER) stress triggers the evolutionarily conserved unfolded protein response in soybean, but it also communicates with other adaptive signaling responses, such as osmotic stress-induced and ER stress-induced programmed cell death. These two signaling pathways converge at the level of gene transcription to activate an integrated cascade that is mediated by N-rich proteins (NRPs). Here, we describe a novel transcription factor, GmERD15 (Glycine max Early Responsive to Dehydration 15), which is induced by ER stress and osmotic stress to activate the expression of NRP genes. GmERD15 was isolated because of its capacity to stably associate with the NRP-B promoter in yeast. It specifically binds to a 187-bp fragment of the NRP-B promoter in vitro and activates the transcription of a reporter gene in yeast. Furthermore, GmERD15 was found in both the cytoplasm and the nucleus, and a ChIP assay revealed that it binds to the NRP-B promoter in vivo. Expression of GmERD15 in soybean protoplasts activated the NRP-B promoter and induced expression of the NRP-B gene. Collectively, these results support the interpretation that GmERD15 functions as an upstream component of stress-induced NRP-B-mediated signaling to connect stress in the ER to an osmotic stress-induced cell death signal.

  14. Involvement of increased endogenous asymmetric dimethylarginine in the hepatic endoplasmic reticulum stress of type 2 diabetic rats.

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    Yi-Ping Leng

    Full Text Available OBJECTIVE: Increasing evidence suggested that endoplasmic reticulum (ER stress contributes to insulin resistance, which plays an important role in the development of type 2 diabetes mellitus (T2DM. Accumulation of endogenous nitric oxide synthase (NOS inhibitor, asymmetric dimethylarginine (ADMA, is associated with insulin resistance, T2DM, and diabetic cardiovascular complications, although the mechanisms have not been elucidated. This study was to determine whether elevated endogenous ADMA is involved in hepatic ER stress of type 2 diabetic rats, verify their causal relationship, and elucidate the potential mechanism underlying ADMA induced ER stress in rat hepatocytes. METHODS: Immunoglobulin binding protein (Bip transcription, eukaryotic initiation factor 2α kinase (eIF2α phosphorylation, X box-binding protein-1 (XBP-1 mRNA splicing and C/EBP homologues protein (CHOP expression were measured to reflect ER stress. Contents of ADMA and nitrite/nitrate as well as activities or expression of NOS and dimethylarginine dimethylaminohydrolase (DDAH were detected to show the changes in DDAH/ADMA/NOS/NO pathway. The lipid peroxidation product malondialdehyde content and antioxidant enzyme superoxide dismutase activity were analyzed to evaluate oxidative stress. RESULTS: ER stress was provoked in the liver of type 2 diabetic rats, as expressed by increases of Bip transcription, eIF2α phosphorylation, XBP-1 splicing and CHOP expression, all of which were in parallel with the elevation of serum ADMA, suppression of NO generation, NOS and DDAH activities in the liver. Exposure of hepatocytes to ADMA or hydrogen peroxide also induced ER stress, which was associated with the inhibition of NO production and increase of oxidative stress. Treatment of hepatocytes with antioxidant pyrrolidine dithiocarbamate not only decreased ADMA-induced oxidative stress and inhibition of NO production but also reduced ADMA-triggered ER stress. CONCLUSIONS: These results

  15. Downregulation of miR-205 modulates cell susceptibility to oxidative and endoplasmic reticulum stresses in renal tubular cells.

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    Shiyo Muratsu-Ikeda

    Full Text Available BACKGROUND: Oxidative stress and endoplasmic reticulum (ER stress play a crucial role in tubular damage in both acute kidney injury (AKI and chronic kidney disease (CKD. While the pathophysiological contribution of microRNAs (miRNA to renal damage has also been highlighted, the effect of miRNA on renal damage under oxidative and ER stresses conditions remains elusive. METHODS: We assessed changes in miRNA expression in the cultured renal tubular cell line HK-2 under hypoxia-reoxygenation-induced oxidative stress or ER stress using miRNA microarray assay and real-time RT-PCR. The pathophysiological effect of miRNA was evaluated by cell survival rate, intracellular reactive oxygen species (ROS level, and anti-oxidant enzyme expression in miRNA-inhibited HK-2 or miRNA-overexpressed HK-2 under these stress conditions. The target gene of miRNA was identified by 3'-UTR-luciferase assay. RESULTS: We identified 8 and 10 miRNAs whose expression was significantly altered by oxidative and ER stresses, respectively. Among these, expression of miR-205 was markedly decreased in both stress conditions. Functional analysis revealed that decreased miR-205 led to an increase in cell susceptibility to oxidative and ER stresses, and that this increase was associated with the induction of intracellular ROS and suppression of anti-oxidant enzymes. While increased miR-205 by itself made no change in cell growth or morphology, cell viability under oxidative or ER stress conditions was partially restored. Further, miR-205 bound to the 3'-UTR of the prolyl hydroxylase 1 (PHD1/EGLN2 gene and suppressed the transcription level of EGLN2, which modulates both intracellular ROS level and ER stress state. CONCLUSIONS: miR-205 serves a protective role against both oxidative and ER stresses via the suppression of EGLN2 and subsequent decrease in intracellular ROS. miR-205 may represent a novel therapeutic target in AKI and CKD associated with oxidative or ER stress in tubules.

  16. Induction of Endoplasmic Reticulum Stress and Unfolded Protein Response Constitutes a Pathogenic Strategy of group A Streptococcus

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    Emanuel eHanski

    2014-08-01

    Full Text Available The connection between bacterial pathogens and unfolded protein response (UPR is poorly explored. In this review we highlight the evidence showing that group A streptococcus (GAS induces endoplasmic reticulum (ER stress and UPR through which it captures the amino acid asparagine (ASN from the host. GAS acts extracellularly and during adherence to host cells it delivers the hemolysin toxins; streptolysin O (SLO and streptolysin S (SLS. By poorly understood pathways, these toxins trigger UPR leading to the induction of the transcriptional regulator ATF4 and consequently to the upregulation of asparagine synthetase (ASNS transcription leading to production and release of ASN. GAS senses ASN and alters gene expression profile accordingly, and increases the rate of multiplication. We suggest that induction of UPR by GAS and by other bacterial pathogens represent means through which bacterial pathogens gain nutrients from the host, obviating the need to become internalized or inflict irreversible cell damage.

  17. Exogenous hepatitis B virus envelope proteins induce endoplasmic reticulum stress: involvement of cannabinoid axis in liver cancer cells

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    Montalbano, Roberta; Honrath, Birgit; Wissniowski, Thaddeus Till; Elxnat, Moritz; Roth, Silvia; Ocker, Matthias; Quint, Karl; Churin, Yuri; Roederfeld, Martin; Schroeder, Dirk; Glebe, Dieter; Roeb, Elke; Fazio, Pietro Di

    2016-01-01

    HBV represents the most common chronic viral infection and major cause of hepatocellular carcinoma (HCC), although its exact role in liver tumorigenesis is unclear. Massive storage of the small (SHBs), middle (MHBs) and large surface (LHBs) HBV envelope proteins leads to cell stress and sustained inflammatory responses. Cannabinoid (CB) system is involved in the pathogenesis of liver diseases, stimulating acute and chronic inflammation, liver damage and fibrogenesis; it triggers endoplasmic reticulum (ER) stress response. The aim of our work was to investigate the activation of ER stress pathway after ectopic HBV envelope proteins expression, in liver cancer cells, and the role exerted by CB receptors. PCR, immunofluorescence and western blotting showed that exogenous LHBs and MHBs induce a clear ER stress response in Huh-7 cells expressing CB1 receptor. Up-regulation of the chaperone BiP/GRP78 (Binding Immunoglobulin Protein/Glucose-Regulated Protein 78) and of the transcription factor CHOP/GADD153 (C/EBP Homologous Protein/Growth Arrest and DNA Damage inducible gene 153), phosphorylation of PERK (PKR-like ER Kinase) and eIF2α (Eukaryotic Initiation Factor 2α) and splicing of XBP1 (X-box binding protein 1) was observed. CB1−/− HepG2 cells did not show any ER stress activation. Inhibition of CB1 receptor counteracted BiP expression in transfected Huh-7 and in HBV+ PLC/PRF/5 cells; whereas no effect was observed in HBV− HLF cells. These results suggest that HBV envelope proteins are able to induce the ER stress pathway. CB1 expression is directly correlated with ER stress function. Further investigations are needed to clarify the involvement of cannabinoid in HCC progression after HBV infection. PMID:26967385

  18. mTOR inhibition increases cell viability via autophagy induction during endoplasmic reticulum stress - An experimental and modeling study.

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    Kapuy, Orsolya; Vinod, P K; Bánhegyi, Gábor

    2014-01-01

    Unfolded or misfolded proteins in the endoplasmic reticulum (ER) trigger an adaptive ER stress response known as unfolded protein response (UPR). Depending on the severity of ER stress, either autophagy-controlled survival or apoptotic cell death can be induced. The molecular mechanisms by which UPR controls multiple fate decisions have started to emerge. One such molecular mechanism involves a master regulator of cell growth, mammalian target of rapamycin (mTOR), which paradoxically is shown to have pro-apoptotic role by mutually interacting with ER stress response. How the interconnections between UPR and mTOR influence the dynamics of autophagy and apoptosis activation is still unclear. Here we make an attempt to explore this problem by using experiments and mathematical modeling. The effect of perturbed mTOR activity in ER stressed cells was studied on autophagy and cell viability by using agents causing mTOR pathway inhibition (such as rapamycin or metyrapone). We observed that mTOR inhibition led to an increase in cell viability and was accompanied by an increase in autophagic activity. It was also shown that autophagy was activated under conditions of severe ER stress but that in the latter phase of stress it was inhibited at the time of apoptosis activation. Our mathematical model shows that both the activation threshold and temporal dynamics of autophagy and apoptosis inducers are sensitive to variation in mTOR activity. These results confirm that autophagy has cytoprotective role and is activated in mutually exclusive manner with respect to ER stress levels.

  19. Involvement of dopamine receptors in binge methamphetamine-induced activation of endoplasmic reticulum and mitochondrial stress pathways.

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    Genevieve Beauvais

    Full Text Available Single large doses of methamphetamine (METH cause endoplasmic reticulum (ER stress and mitochondrial dysfunctions in rodent striata. The dopamine D(1 receptor appears to be involved in these METH-mediated stresses. The purpose of this study was to investigate if dopamine D(1 and D(2 receptors are involved in ER and mitochondrial stresses caused by single-day METH binges in the rat striatum. Male Sprague-Dawley rats received 4 injections of 10 mg/kg of METH alone or in combination with a putative D(1 or D(2 receptor antagonist, SCH23390 or raclopride, respectively, given 30 min prior to each METH injection. Rats were euthanized at various timepoints afterwards. Striatal tissues were used in quantitative RT-PCR and western blot analyses. We found that binge METH injections caused increased expression of the pro-survival genes, BiP/GRP-78 and P58(IPK, in a SCH23390-sensitive manner. METH also caused up-regulation of ER-stress genes, Atf2, Atf3, Atf4, CHOP/Gadd153 and Gadd34. The expression of heat shock proteins (HSPs was increased after METH injections. SCH23390 completely blocked induction in all analyzed ER stress-related proteins that included ATF3, ATF4, CHOP/Gadd153, HSPs and caspase-12. The dopamine D(2-like antagonist, raclopride, exerted small to moderate inhibitory influence on some METH-induced changes in ER stress proteins. Importantly, METH caused decreases in the mitochondrial anti-apoptotic protein, Bcl-2, but increases in the pro-apoptotic proteins, Bax, Bad and cytochrome c, in a SCH23390-sensitive fashion. In contrast, raclopride provided only small inhibition of METH-induced changes in mitochondrial proteins. These findings indicate that METH-induced activation of striatal ER and mitochondrial stress pathways might be more related to activation of SCH23390-sensitive receptors.

  20. Involvement of dopamine receptors in binge methamphetamine-induced activation of endoplasmic reticulum and mitochondrial stress pathways.

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    Beauvais, Genevieve; Atwell, Kenisha; Jayanthi, Subramaniam; Ladenheim, Bruce; Cadet, Jean Lud

    2011-01-01

    Single large doses of methamphetamine (METH) cause endoplasmic reticulum (ER) stress and mitochondrial dysfunctions in rodent striata. The dopamine D(1) receptor appears to be involved in these METH-mediated stresses. The purpose of this study was to investigate if dopamine D(1) and D(2) receptors are involved in ER and mitochondrial stresses caused by single-day METH binges in the rat striatum. Male Sprague-Dawley rats received 4 injections of 10 mg/kg of METH alone or in combination with a putative D(1) or D(2) receptor antagonist, SCH23390 or raclopride, respectively, given 30 min prior to each METH injection. Rats were euthanized at various timepoints afterwards. Striatal tissues were used in quantitative RT-PCR and western blot analyses. We found that binge METH injections caused increased expression of the pro-survival genes, BiP/GRP-78 and P58(IPK), in a SCH23390-sensitive manner. METH also caused up-regulation of ER-stress genes, Atf2, Atf3, Atf4, CHOP/Gadd153 and Gadd34. The expression of heat shock proteins (HSPs) was increased after METH injections. SCH23390 completely blocked induction in all analyzed ER stress-related proteins that included ATF3, ATF4, CHOP/Gadd153, HSPs and caspase-12. The dopamine D(2)-like antagonist, raclopride, exerted small to moderate inhibitory influence on some METH-induced changes in ER stress proteins. Importantly, METH caused decreases in the mitochondrial anti-apoptotic protein, Bcl-2, but increases in the pro-apoptotic proteins, Bax, Bad and cytochrome c, in a SCH23390-sensitive fashion. In contrast, raclopride provided only small inhibition of METH-induced changes in mitochondrial proteins. These findings indicate that METH-induced activation of striatal ER and mitochondrial stress pathways might be more related to activation of SCH23390-sensitive receptors.

  1. alpha-Linolenic acid protects renal cells against palmitic acid lipotoxicity via inhibition of endoplasmic reticulum stress.

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    Katsoulieris, Elias; Mabley, Jon G; Samai, Mohamed; Green, Irene C; Chatterjee, Prabal K

    2009-11-25

    Unsaturated fatty acids may counteract the lipotoxicity associated with saturated fatty acids. Palmitic acid induced endoplasmic reticulum (ER) stress and caused apoptotic and necrotic cell death in the renal proximal tubular cell line, NRK-52E. We investigated whether alpha-linolenic acid, an unsaturated fatty acid, protected against ER stress and cell death induced by palmitic acid or by other non-nutrient ER stress generators. Incubation of NRK-52E cells for 24h with palmitic acid produced a significant increase in apoptosis and necrosis. Palmitic acid also increased levels of three indicators of ER stress - the phosphorylated form of the eukaryotic initiation factor 2alpha (eIF2alpha), C/EBP homologous protein (CHOP), and glucose regulated protein 78 (GRP78). alpha-Linolenic acid dramatically reduced cell death and levels of all three indicators of ER stress brought about by palmitic acid. Tunicamycin, which induces ER stress by glycosylation of proteins, produced similar effects to those obtained using palmitic acid; its effects were partially reversed by alpha-linolenic acid. Salubrinal (a phosphatase inhibitor) causes increased levels of the phosphorylated form of eIF2alpha - this effect was partially reversed by alpha-linolenic acid. Palmitoleate, a monosaturated fatty acid, had similar effects to those of alpha-linolenic acid. These results suggest that part of the mechanism of protection of the kidney by unsaturated fatty acids is through inhibition of ER stress, eIF2alpha phosphorylation and consequential reduction of CHOP protein expression and apoptotic renal cell death.

  2. Increased classical endoplasmic reticulum stress is sufficient to reduce chondrocyte proliferation rate in the growth plate and decrease bone growth.

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    Louise H W Kung

    Full Text Available Mutations in genes encoding cartilage oligomeric matrix protein and matrilin-3 cause a spectrum of chondrodysplasias called multiple epiphyseal dysplasia (MED and pseudoachondroplasia (PSACH. The majority of these diseases feature classical endoplasmic reticulum (ER stress and activation of the unfolded protein response (UPR as a result of misfolding of the mutant protein. However, the importance and the pathological contribution of ER stress in the disease pathogenesis are unknown. The aim of this study was to investigate the generic role of ER stress and the UPR in the pathogenesis of these diseases. A transgenic mouse line (ColIITgcog was generated using the collagen II promoter to drive expression of an ER stress-inducing protein (Tgcog in chondrocytes. The skeletal and histological phenotypes of these ColIITgcog mice were characterised. The expression and intracellular retention of Tgcog induced ER stress and activated the UPR as characterised by increased BiP expression, phosphorylation of eIF2α and spliced Xbp1. ColIITgcog mice exhibited decreased long bone growth and decreased chondrocyte proliferation rate. However, there was no disruption of chondrocyte morphology or growth plate architecture and perturbations in apoptosis were not apparent. Our data demonstrate that the targeted induction of ER stress in chondrocytes was sufficient to reduce the rate of bone growth, a key clinical feature associated with MED and PSACH, in the absence of any growth plate dysplasia. This study establishes that classical ER stress is a pathogenic factor that contributes to the disease mechanism of MED and PSACH. However, not all the pathological features of MED and PSACH were recapitulated, suggesting that a combination of intra- and extra-cellular factors are likely to be responsible for the disease pathology as a whole.

  3. HIV protease inhibitors disrupt lipid metabolism by activating endoplasmic reticulum stress and inhibiting autophagy activity in adipocytes.

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    Beth S Zha

    Full Text Available BACKGROUND: HIV protease inhibitors (PI are core components of Highly Active Antiretroviral Therapy (HAART, the most effective treatment for HIV infection currently available. However, HIV PIs have now been linked to lipodystrophy and dyslipidemia, which are major risk factors for cardiovascular disease and metabolic syndrome. Our previous studies have shown that HIV PIs activate endoplasmic reticulum (ER stress and disrupt lipid metabolism in hepatocytes and macrophages. Yet, little is known on how HIV PIs disrupt lipid metabolism in adipocytes, a major cell type involved in the pathogenesis of metabolic syndrome. METHODOLOGY AND PRINCIPAL FINDINGS: Cultured and primary mouse adipocytes and human adipocytes were used to examine the effect of frequently used HIV PIs in the clinic, lopinavir/ritonavir, on adipocyte differentiation and further identify the underlying molecular mechanism of HIV PI-induced dysregulation of lipid metabolism in adipocytes. The results indicated that lopinavir alone or in combination with ritonavir, significantly activated the ER stress response, inhibited cell differentiation, and induced cell apoptosis in adipocytes. In addition, HIV PI-induced ER stress was closely linked to inhibition of autophagy activity. We also identified through the use of primary adipocytes of CHOP(-/- mice that CHOP, the major transcriptional factor of the ER stress signaling pathway, is involved in lopinavir/ritonavir-induced inhibition of cell differentiation in adipocytes. In addition, lopinavir/ritonavir-induced ER stress appears to be associated with inhibition of autophagy activity in adipocytes. CONCLUSION AND SIGNIFICANCE: Activation of ER stress and impairment of autophagy activity are involved in HIV PI-induced dysregulation of lipid metabolism in adipocytes. The key components of ER stress and autophagy signaling pathways are potential therapeutic targets for HIV PI-induced metabolic side effects in HIV patients.

  4. Endoplasmic reticulum stress mediates sulforaphane-induced apoptosis of HepG2 human hepatocellular carcinoma cells.

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    Zou, Xiang; Qu, Zhongyuan; Fang, Yueni; Shi, Xin; Ji, Yubin

    2017-01-01

    Sulforaphane (SFN) is a naturally occurring chemopreventive agent, which effectively inhibits proliferation of HepG2 human hepatocellular carcinoma cells via mitochondria‑mediated apoptosis. Endoplasmic reticulum stress is considered the most important cause of cell apoptosis; therefore, the present study aimed to determine whether the endoplasmic reticulum pathway was involved in SFN-induced apoptosis of HepG2 cells. An MTT assay was used to detect the inhibitory effects of SFN on HepG2 cells. Fluorescence microscopy was used to observe the morphological changes in apoptotic cells, and western blot analysis was conducted to detect the expression of binding immunoglobulin protein (Bip)/glucose-regulated protein 78 (GRP78), X‑box binding protein‑1 (XBP‑1) and BH3 interacting domain death agonist (Bid). Furthermore, flow cytometry was used to determine the apoptotic rate of HepG2 cells, and the protein expression of C/EBP homologous protein (CHOP)/growth arrest‑ and DNA damage‑inducible gene 153 (GADD153) and caspase-12 in HepG2 cells. The results indicated that SFN significantly inhibited the proliferation of HepG2 cells; the half maximal inhibitory concentration values were 32.03±0.96, 20.90±1.96 and 13.87±0.44 µmol/l, following treatment with SFN for 24, 48 and 72 h, respectively. Following 48 h of SFN treatment (10, 20 and 40 µmol/l), the apoptotic rates of HepG2 cells were 31.8, 61.3 and 77.1%, respectively. Furthermore, after 48 h of exposure to SFN, the cells presented typical morphological alterations of apoptosis, as detected under fluorescence microscopy. Treatment with SFN for 48 h also significantly upregulated the protein expression levels of Bip/GRP78, XBP‑1, caspase‑12, CHOP/GADD153 and Bid in HepG2 cells. In conclusion, endoplasmic reticulum stress may be considered the most important mechanism underlying SFN-induced apoptosis in HepG2 cells.

  5. Effect of berberine on endoplasmic reticulum stress PERK apoptosis pathway in HK-2 cells by high fructose

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    Yong ZHANG

    2017-02-01

    Full Text Available Objective To investigate the effect of berberine on endoplasmic reticulum stress PERK apoptosis pathway in HK-2 cells by high fructose. Methods HK-2 cells were grown in DMEM/F12, containing 10% fetal bovine serum (FBS and divided randomly into four groups: normal control group (Group C; Fructose group (Group F: it contains 25mmol/L fructose culture; Berberine group (Group B: 25mmol/L fructose + 10μmol/L berberine treatment group; TUDCA group (Group T: 25mmol/L fructose +2μmol/L TUDCA culture group; Cells were collected after culturing 24h. The expression of glucose-regulated protein 78 (GRP78, CHOP protein and the phosphorylation levels of PERK, eIF2α were tested by Western blotting. The cell cycles were detected by flow cytometry and the apoptosis of cells were detected by TUNEL staining. Results Western blotting showed that the expression of GRP78 and CHOP protein in group F was significantly higher than that in group C, and the levels of p-PERK and p-eIF2α in group F were significantly higher than those in group F. Compared with group F, GRP78, CHOP, p-PERK and p-eIF2α in group B and T were significantly lower (P0.05. Conclusion Persistent high fructose can activate the intracellular PERK pathway in HK-2 cells, causing endoplasmic reticulum stress. Berberine can inhibit the fructose-induced PERK and eIF2α phosphorylation, down-regulated the expression of GRP78, CHOP protein, thus by regulating PERK Pathways to alleviate cell cycle arrest and reduce cell apoptosis. DOI: 10.11855/j.issn.0577-7402.2017.01.02

  6. The SGK1 inhibitor SI113 induces autophagy, apoptosis, and endoplasmic reticulum stress in endometrial cancer cells.

    Science.gov (United States)

    Conza, Domenico; Mirra, Paola; Calì, Gaetano; Tortora, Teresa; Insabato, Luigi; Fiory, Francesca; Schenone, Silvia; Amato, Rosario; Beguinot, Francesco; Perrotti, Nicola; Ulianich, Luca

    2017-12-01

    Endometrial cancer is often characterized by PI3K/AKT pathway deregulation. Recently it has been suggested that SGK1, a serine/threonine protein kinase that shares structural and functional similarities with the AKT family, might play a role in cancer, since its expression and/or activity has been found to be deregulated in different human tumors. However, the role of SGK1 in endometrial cancer has been poorly investigated. Here, we show that SGK1 expression is increased in tissue specimens from neoplastic endometrium. The SGK1 inhibitor SI113 induced a significant reduction of endometrial cancer cells viability, measured by the (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. This effect was associated to the increase of autophagy, as revealed by the increase of the markers LC3B-II and beclin I, detected by both immunofluorescence and western blot analysis. SI113 treatment caused also apoptosis of endometrial cancer cells, evidenced by the cleavage of the apoptotic markers PARP and Caspase-9. Intriguingly, these effects were associated to the induction of endoplasmic reticulum stress markers GRP78 and CHOP evaluated by both Real-Time RT-PCR and Western Blot analysis. Increased expression of SGK1 in endometrial cancer tissues suggest a role for SGK1 in this type of cancer, as reported for other malignancies. Moreover, the efficacy of SI113 in affecting endometrial cancer cells viability, possibly via endoplasmic reticulum stress activation, identifies SGK1 as an attractive molecular target for new tailored therapeutic intervention for the treatment of endometrial cancer. © 2017 Wiley Periodicals, Inc.

  7. Stress-resolved and cockroach-friendly piezoelectric sensors

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    Cooper, R.; Lee, H.; Butler, J.; Gonzalez, J.; Yi, J.; Vinson, B.; Liang, H.

    2008-04-01

    We investigate effects of bending stress on piezoelectric properties of polyvinylidene fluoride (PVDF) as a polymer sensor. The sensor was designed and fabricated into a special size and shape so that it can be attached to small insects, such as the American cockroach (Periplaneta Americana) to measure the insects' locomotion. The performance of the sensor is studied using a controlled linear stage to buckle the sensor mimicking the bending of the sensor due to the leg movements of cockroaches. For comparison, a roach robot was used for multi-leg study. Results indicate that buckling motion of the sensor produce an output that is different from regular stretching effect. The sensor-generated charge depends on the localized stress distribution and dipole alignment. This paper discusses the methods of characterization of piezoelectricity useful for insect applications.

  8. Mechanisms of Neuronal Protection against Excitotoxicity, Endoplasmic Reticulum Stress, and Mitochondrial Dysfunction in Stroke and Neurodegenerative Diseases

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    Howard Prentice

    2015-01-01

    Full Text Available In stroke and neurodegenerative disease, neuronal excitotoxicity, caused by increased extracellular glutamate levels, is known to result in calcium overload and mitochondrial dysfunction. Mitochondrial deficits may involve a deficiency in energy supply as well as generation of high levels of oxidants which are key contributors to neuronal cell death through necrotic and apoptotic mechanisms. Excessive glutamate receptor stimulation also results in increased nitric oxide generation which can be detrimental to cells as nitric oxide interacts with superoxide to form the toxic molecule peroxynitrite. High level oxidant production elicits neuronal apoptosis through the actions of proapoptotic Bcl-2 family members resulting in mitochondrial permeability transition pore opening. In addition to apoptotic responses to severe stress, accumulation of misfolded proteins and high levels of oxidants can elicit endoplasmic reticulum (ER stress pathways which may also contribute to induction of apoptosis. Two categories of therapeutics are discussed that impact major pro-death events that include induction of oxidants, calcium overload, and ER stress. The first category of therapeutic agent includes the amino acid taurine which prevents calcium overload and is also capable of preventing ER stress by inhibiting specific ER stress pathways. The second category involves N-methyl-D-aspartate receptor (NMDA receptor partial antagonists illustrated by S-Methyl-N, N-diethyldithiocarbamate sulfoxide (DETC-MeSO, and memantine. DETC-MeSO is protective through preventing excitotoxicity and calcium overload and by blocking specific ER stress pathways. Another NMDA receptor partial antagonist is memantine which prevents excessive glutamate excitation but also remarkably allows maintenance of physiological neurotransmission. Targeting of these major sites of neuronal damage using pharmacological agents is discussed in terms of potential therapeutic approaches for

  9. Mechanisms of Neuronal Protection against Excitotoxicity, Endoplasmic Reticulum Stress, and Mitochondrial Dysfunction in Stroke and Neurodegenerative Diseases.

    Science.gov (United States)

    Prentice, Howard; Modi, Jigar Pravinchandra; Wu, Jang-Yen

    2015-01-01

    In stroke and neurodegenerative disease, neuronal excitotoxicity, caused by increased extracellular glutamate levels, is known to result in calcium overload and mitochondrial dysfunction. Mitochondrial deficits may involve a deficiency in energy supply as well as generation of high levels of oxidants which are key contributors to neuronal cell death through necrotic and apoptotic mechanisms. Excessive glutamate receptor stimulation also results in increased nitric oxide generation which can be detrimental to cells as nitric oxide interacts with superoxide to form the toxic molecule peroxynitrite. High level oxidant production elicits neuronal apoptosis through the actions of proapoptotic Bcl-2 family members resulting in mitochondrial permeability transition pore opening. In addition to apoptotic responses to severe stress, accumulation of misfolded proteins and high levels of oxidants can elicit endoplasmic reticulum (ER) stress pathways which may also contribute to induction of apoptosis. Two categories of therapeutics are discussed that impact major pro-death events that include induction of oxidants, calcium overload, and ER stress. The first category of therapeutic agent includes the amino acid taurine which prevents calcium overload and is also capable of preventing ER stress by inhibiting specific ER stress pathways. The second category involves N-methyl-D-aspartate receptor (NMDA receptor) partial antagonists illustrated by S-Methyl-N, N-diethyldithiocarbamate sulfoxide (DETC-MeSO), and memantine. DETC-MeSO is protective through preventing excitotoxicity and calcium overload and by blocking specific ER stress pathways. Another NMDA receptor partial antagonist is memantine which prevents excessive glutamate excitation but also remarkably allows maintenance of physiological neurotransmission. Targeting of these major sites of neuronal damage using pharmacological agents is discussed in terms of potential therapeutic approaches for neurological disorders.

  10. Synergistic Interaction of Hypertension and Diabetes in Promoting Kidney Injury and the Role of Endoplasmic Reticulum Stress.

    Science.gov (United States)

    Wang, Zhen; do Carmo, Jussara M; Aberdein, Nicola; Zhou, Xinchun; Williams, Jan M; da Silva, Alexandre A; Hall, John E

    2017-05-01

    Diabetes mellitus and hypertension are major risk factors for chronic kidney injury, together accounting for >70% of end-stage renal disease. In this study, we assessed interactions of hypertension and diabetes mellitus in causing kidney dysfunction and injury and the role of endoplasmic reticulum (ER) stress. Hypertension was induced by aorta constriction (AC) between the renal arteries in 6-month-old male Goto-Kakizaki (GK) type 2 diabetic and control Wistar rats. Fasting plasma glucose averaged 162±11 and 87±2 mg/dL in GK and Wistar rats, respectively. AC produced hypertension in the right kidney (above AC) and near normal blood pressure in the left kidney (below AC), with both kidneys exposed to the same levels of glucose, circulating hormones, and neural influences. After 8 weeks of AC, blood pressure above the AC (and in the right kidney) increased from 109±1 to 152±5 mm Hg in GK rats and from 106±4 to 141±5 mm Hg in Wistar rats. The diabetic-hypertensive right kidneys in GK-AC rats had much greater increases in albumin excretion and histological injury compared with left kidneys (diabetes mellitus only) of GK rats or right kidneys (hypertension only) of Wistar-AC rats. Marked increases in ER stress and oxidative stress indicators were observed in diabetic-hypertensive kidneys of GK-AC rats. Inhibition of ER stress with tauroursodeoxycholic acid for 6 weeks reduced blood pressure (135±4 versus 151±4 mm Hg), albumin excretion, ER and oxidative stress, and glomerular injury, while increasing glomerular filtration rate in hypertensive-diabetic kidneys. These results suggest that diabetes mellitus and hypertension interact synergistically to promote kidney dysfunction and injury via ER stress. © 2017 American Heart Association, Inc.

  11. YiQiFuMai Powder Injection Ameliorates Cerebral Ischemia by Inhibiting Endoplasmic Reticulum Stress-Mediated Neuronal Apoptosis

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    Guosheng Cao

    2016-01-01

    Full Text Available YiQiFuMai (YQFM powder injection as a modern preparation derived from Sheng Mai San, a traditional Chinese medicine, has been widely used in the treatment of cardiovascular and cerebrovascular diseases. However, its neuroprotective effect and underlying mechanism in cerebral ischemia remain to be explored. The present study was designed to investigate the neuroprotective effect of YQFM on endoplasmic reticulum (ER stress-mediated neuronal apoptosis in the permanent middle cerebral artery occlusion- (MCAO- injured mice and the oxygen-glucose deprivation- (OGD- induced pheochromocytoma (PC12 cells. The results showed that single administration of YQFM (1.342 g/kg, i.p. could reduce the brain infarction and improve the neurological deficits and the cerebral blood flow (CBF after MCAO for 24 h in mice. Moreover, incubation with YQFM (100, 200, and 400 μg/mL could increase the cell viability, decrease the caspase-3 activity, and inhibit the cell apoptosis in OGD-induced PC12 cells for 12 h. In addition, YQFM treatment could significantly modulate cleaved caspase-3 and Bcl-2 expressions and inhibit the expressions of ER stress-related marker proteins and signaling pathways in vivo and in vitro. In conclusion, our findings provide the first evidence that YQFM ameliorates cerebral ischemic injury linked with modulating ER stress-related signaling pathways, which provided some new insights for its prevention and treatment of cerebral ischemia diseases.

  12. Neuroprotective effects of Activin A on endoplasmic reticulum stress-mediated apoptotic and autophagic PC12 cell death

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    Long-xing Xue

    2017-01-01

    Full Text Available Activin A, a member of the transforming growth factor-beta superfamily, plays a neuroprotective role in multiple neurological diseases. Endoplasmic reticulum (ER stress-mediated apoptotic and autophagic cell death is implicated in a wide range of diseases, including cerebral ischemia and neurodegenerative diseases. Thapsigargin was used to induce PC12 cell death, and Activin A was used for intervention. Our results showed that Activin A significantly inhibited morphological changes in thapsigargin-induced apoptotic cells, and the expression of apoptosis-associated proteins [cleaved-caspase-12, C/EBP homologous protein (CHOP and cleaved-caspase-3] and biomarkers of autophagy (Beclin-1 and light chain 3, and downregulated the expression of thapsigargin-induced ER stress-associated proteins [inositol requiring enzyme-1 (IRE1, tumor necrosis factor receptor-associated factor 2 (TRAF2, apoptosis signal-regulating kinase 1 (ASK1, c-Jun N-terminal kinase (JNK and p38]. The inhibition of thapsigargin-induced cell death was concentration-dependent. These findings suggest that administration of Activin A protects PC12 cells against ER stress-mediated apoptotic and autophagic cell death by inhibiting the activation of the IRE1-TRAF2-ASK1-JNK/p38 cascade.

  13. Size dependent effect of ZnO nanoparticles on endoplasmic reticulum stress signaling pathway in murine liver.

    Science.gov (United States)

    Kuang, Huijuan; Yang, Pengfei; Yang, Lin; Aguilar, Zoraida P; Xu, Hengyi

    2016-11-05

    ZnO nanoparticles (NPs) have been assessed to show adverse effects on the liver, but the molecular mechanisms and the role of nanoparticle properties in these adverse reactions have not been sufficiently studied. In this study, the toxicity of various sizes of ZnO particles (bulk, 90nm, and 30nm) that were ingested orally over a period of 3days were evaluated in mice. The blood biochemistry, hematological analyses, and histopathological evaluation showed that there was apparent toxicity caused by smaller ZnO NPs (30nm) in liver. The smallest ZnO NPs showed highest accumulation in the mice liver. The RT-qPCR data indicated that 30nm ZnO NPs can induce significant endoplasmic reticulum (ER) stress responses. The ER stress marker of PERK, eIF2α, ATF4, Chop, JNK, caspase-12, caspase-9, GRP94, and Bax at the mRNA levels were higher expression in 30nm ZnO NP than that in bulk or 90nm ZnO. These findings implied that the smaller ZnO NPs (30nm) activated ER stress responses that signified severe apoptosis in murine liver.

  14. Interaction between caspase-8 activation and endoplasmic reticulum stress in glycochenodeoxycholic acid-induced apoptotic HepG2 cells.

    Science.gov (United States)

    Iizaka, Toru; Tsuji, Mayumi; Oyamada, Hideto; Morio, Yuri; Oguchi, Katsuji

    2007-11-30

    The accumulation of hydrophobic bile acid, such as glycochenodeoxycholic acid (GCDCA), in the liver has been thought to induce hepatocellular damage in human chronic cholestatic liver diseases. We previously reported that GCDCA-induced apoptosis was promoted by both mitochondria-mediated and endoplasmic reticulum (ER) stress-associated pathways in rat hepatocytes. In this study, we elucidated the relationship between these pathways in GCDCA-induced apoptotic HepG2 cells. HepG2 cells were treated with GCDCA (100-500microM) with or without a caspase-8 inhibitor, Z-IETD-fluoromethyl ketone (Z-IETD-FMK) (30microM) for 3-24h. We demonstrated the presence of both apoptotic pathways in these cells; that is, we showed increases in cleaved caspase-3 proteins, the release of cytochrome c from mitochondria, and the expression of ER resident molecular chaperone Bip mRNA and ER stress response-associated transcription factor Chop mRNA. On the other hand, pretreatment with Z-IETD-FMK significantly reduced the increases, compared with treatment with GCDCA alone. Immunofluorescence microscopic analysis showed that treatment with GCDCA increased the cleavage of BAP31, an integral membrane protein of ER, and pretreatment with Z-IETD-FMK suppressed the increase of caspase-8 and BAP31 cleavage. In conclusion, these results suggest that intact activated caspase-8 may promote and amplify the ER stress response by cleaving BAP31 in GCDCA-induced apoptotic cells.

  15. Regulation of calnexin sub-cellular localization modulates endoplasmic reticulum stress-induced apoptosis in MCF-7 cells.

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    Delom, Frédéric; Fessart, Delphine; Chevet, Eric

    2007-02-01

    The endoplasmic reticulum (ER) is the cellular compartment where proteins enter the secretory pathway, undergo post-translational modifications and acquire a correct conformation. If these functions are chronically altered, specific ER stress signals are triggered to promote cell death through the intrinsic apoptotic pathway. Here, we show that tunicamycin causes significant alteration of calnexin sub-cellular distribution in MCF-7 cells. Interestingly, this correlates with the absence of both tunicamycin-induced calnexin phosphorylation as well as tunicamycin-induced cell death. Under these conditions, calnexin-associated Bap31, an ER integral membrane protein, is subjected to a caspase-8 cleavage pattern within a specific sub-compartment of the ER. These results suggest that MCF-7 resistance to ER stress-induced apoptosis is partially mediated by the expression level of calnexin which in turn controls its sub-cellular localization, and its association with Bap31. These data may delineate a resistance mechanism to the ER stress-induced intrinsic apoptotic pathway.

  16. Transgenic overexpression of 14-3-3 zeta protects hippocampus against endoplasmic reticulum stress and status epilepticus in vivo.

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    Gary P Brennan

    Full Text Available 14-3-3 proteins are ubiquitous molecular chaperones that are abundantly expressed in the brain where they regulate cell functions including metabolism, the cell cycle and apoptosis. Brain levels of several 14-3-3 isoforms are altered in diseases of the nervous system, including epilepsy. The 14-3-3 zeta (ζ isoform has been linked to endoplasmic reticulum (ER function in neurons, with reduced levels provoking ER stress and increasing vulnerability to excitotoxic injury. Here we report that transgenic overexpression of 14-3-3ζ in mice results in selective changes to the unfolded protein response pathway in the hippocampus, including down-regulation of glucose-regulated proteins 78 and 94, activating transcription factors 4 and 6, and Xbp1 splicing. No differences were found between wild-type mice and transgenic mice for levels of other 14-3-3 isoforms or various other 14-3-3 binding proteins. 14-3-3ζ overexpressing mice were potently protected against cell death caused by intracerebroventricular injection of the ER stressor tunicamycin. 14-3-3ζ overexpressing mice were also potently protected against neuronal death caused by prolonged seizures. These studies demonstrate that increased 14-3-3ζ levels protect against ER stress and seizure-damage despite down-regulation of the unfolded protein response. Delivery of 14-3-3ζ may protect against pathologic changes resulting from prolonged or repeated seizures or where injuries provoke ER stress.

  17. Astragalus polysaccharide reduces hepatic endoplasmic reticulum stress and restores glucose homeostasis in a diabetic KKAy mouse model

    Institute of Scientific and Technical Information of China (English)

    Xian-qing MAO; Yong WU; Ke WU; Ming LIU; Jing-fang ZHANG; Feng ZOU; Jing-ping OU-YANG

    2007-01-01

    Aim: To examine the potential effects of Astragalus polysaccharide (APS) on hepatic endoplasmic reticulum (ER) stress in vivo and in vitro and its link with hypoglycemia activity, thus establishing the mechanism underlying the hypogly- cemic action of APS. Methods: The obese and type 2 diabetic KKAy mouse model, which is the yellow offspring of the KK mice expressed Ay2 gene (700 mg·kg-12-d-12, 8 weeks) and a high glucose-induced HepG2 cell model (200 μg/mL, 24 h) were treated with APS. The oral glucose tolerance test was measured to reflex insulin sensitivity with the calculated homeostasis model assessment (HOMA- IR) index. XBP1 (Xho1 site-binding protein 1) transcription and splicing, an indica- tor of ER stress, was analyzed by RT-PCR and real-time PCR. The expression and activation of glycogen synthase kinase 3 beta (GSK3β), an insulin signaling protein, was measured by Western blotting. Results: APS can alleviate ER stress in cul- tured cells in vivo. The hyperglycemia status, systemic insulin sensitivity, fatty liver disease, and insulin action in the liver of diabetic mice were partly normalized or improved in response to APSadministration. Conclusion: Our results indicate that APS enables insulin-sensitizing and hypoglycemic activity at least in part by enhancing the adaptive capacity of the ER, which can further promote insulin signal transduction. Thus, APS has promising application in the treatment of type 2 diabetes.

  18. 内质网应激与心血管疾病%Endoplasmic reticulum stress and cardiovascular diseases

    Institute of Scientific and Technical Information of China (English)

    刘蜜

    2011-01-01

    内质网应激是细胞内一种适应性机制,持续或过强的内质网应激则诱导细胞凋亡,造成组织损伤.多项研究显示内质网应激是多种心血管疾病如动脉粥样硬化、缺血性心脏病、心肌肥大、心力衰竭及糖尿痛心肌病等发生、发展的共同通路,干预内质网应激可能成为心血管疾病治疗的新靶点.%Endoplasmic reticulum (ER) stress is initially aimed at compensating for damage but can eventually trigger cell apoptosis if ER dysfunction is severe or prolonged. Plenty of evidence shows that ER stress-induced apoptosis is involved in the pathogenesis and development of many cardiovascular diseases, such as atherosclerosis, ischemic heart disease, myocardial hypertrophy, heart failure, diabetic cardiomyopathy, and so on. Therefore, intervention of ER stress may provide a potential target for treating cardiovascular diseases.

  19. Ursodeoxycholic Acid Attenuates Endoplasmic Reticulum Stress-Related Retinal Pericyte Loss in Streptozotocin-Induced Diabetic Mice

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    Yoo-Ri Chung

    2017-01-01

    Full Text Available Loss of pericytes, an early hallmark of diabetic retinopathy (DR, results in breakdown of the blood-retinal barrier. Endoplasmic reticulum (ER stress may be involved in this process. The purpose of this study was to examine the effects of ursodeoxycholic acid (UDCA, a known ameliorator of ER stress, on pericyte loss in DR of streptozotocin- (STZ- induced diabetic mice. To assess the extent of DR, the integrity of retinal vessels and density of retinal capillaries in STZ-induced diabetic mice were evaluated. Additionally, induction of ER stress and the unfolded protein response (UPR were assessed in diabetic mice and human retinal pericytes exposed to advanced glycation end products (AGE or modified low-density lipoprotein (mLDL. Fluorescein dye leakage during angiography and retinal capillary density were improved in UDCA-treated diabetic mice, compared to the nontreated diabetic group. Among the UPR markers, those involved in the protein kinase-like ER kinase (PERK pathway were increased, while UDCA attenuated UPR in STZ-induced diabetic mice as well as AGE- or mLDL-exposed retinal pericytes in culture. Consequently, vascular integrity was improved and pericyte loss reduced in the retina of STZ-induced diabetic mice. Our findings suggest that UDCA might be effective in protecting against DR.

  20. Folate Protects Hepatocytes of Hyperhomocysteinemia Mice from Apoptosis via Cystic Fibrosis Transmembrane Conductance Regulator (CFTR)-activated Endoplasmic Reticulum Stress.

    Science.gov (United States)

    Yang, Anning; Sun, Yue; Mao, Caiyan; Yang, Songhao; Huang, Min; Deng, Mei; Ding, Ning; Yang, Xiaoling; Zhang, Minghao; Jin, Shaoju; Jiang, Yideng; Huang, Ying

    2017-02-23

    Folate deficiency is a known risk factor for liver injury; however, the underlying mechanism remains unclear. In this study, we employed a high homocysteine-induced liver injury model of Apolipoprotein E-deficient (ApoE(-/-) ) mice fed high-methionine diet and found that high homocysteine induced endoplasmic reticulum (ER) stress and liver cell apoptosis by downregulation of cystic fibrosis transmembrane conductance regulator (CFTR) expression; observations that were attenuated with supplementation of dietary folate. The regulation on CFTR expression was mediated by CFTR promoter methylation and trimethylation of lysine 27 on histone H3 (H3K27me3). Mechanistically, folate inhibited homocysteine-induced CFTR promoter methylation and H3K27me3, which resulted in upregulation of CFTR expression, and reduced ER stress and liver cell apoptosis. Further study showed that folate inhibited the expression of DNA methyltransferase 1 and enhancer of zeste homolog 2, downregulated the cellular concentrations of S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) and upregulated the SAM/SAH ratio, leading to the inhibition of Hcy-induced DNA hypermethylation and H3K27me3 in CFTR promoter. In conclusion, our results provide insight into the protective role of folate in homocysteine-induced ER stress and liver cell apoptosis through the regulation of CFTR expression. This article is protected by copyright. All rights reserved.

  1. Dysregulated LRRK2 signaling in response to endoplasmic reticulum stress leads to dopaminergic neuron degeneration in C. elegans.

    Directory of Open Access Journals (Sweden)

    Yiyuan Yuan

    Full Text Available Mutation of leucine-rich repeat kinase 2 (LRRK2 is the leading genetic cause of Parkinson's Disease (PD, manifested as age-dependent dopaminergic neurodegeneration, but the underlying molecular mechanisms remain unclear. Multiple roles of LRRK2 may contribute to dopaminergic neurodegeneration. Endoplasmic reticulum (ER stress has also been linked to PD pathogenesis, but its interactive mechanism with PD genetic factors is largely unknown. Here, we used C. elegans, human neuroblastoma cells and murine cortical neurons to determine the role of LRRK2 in maintaining dopaminergic neuron viability. We found that LRRK2 acts to protect neuroblastoma cells and C. elegans dopaminergic neurons from the toxicity of 6-hydroxydopamine and/or human α-synuclein, possibly through the p38 pathway, by supporting upregulation of GRP78, a key cell survival molecule during ER stress. A pathogenic LRRK2 mutant (G2019S, however, caused chronic p38 activation that led to death of murine neurons and age-related dopaminergic-specific neurodegeneration in nematodes. These observations establish a critical functional link between LRRK2 and ER stress.

  2. Dysregulated LRRK2 signaling in response to endoplasmic reticulum stress leads to dopaminergic neuron degeneration in C. elegans.

    Science.gov (United States)

    Yuan, Yiyuan; Cao, Pengxiu; Smith, Mark A; Kramp, Kristopher; Huang, Ying; Hisamoto, Naoki; Matsumoto, Kunihiro; Hatzoglou, Maria; Jin, Hui; Feng, Zhaoyang

    2011-01-01

    Mutation of leucine-rich repeat kinase 2 (LRRK2) is the leading genetic cause of Parkinson's Disease (PD), manifested as age-dependent dopaminergic neurodegeneration, but the underlying molecular mechanisms remain unclear. Multiple roles of LRRK2 may contribute to dopaminergic neurodegeneration. Endoplasmic reticulum (ER) stress has also been linked to PD pathogenesis, but its interactive mechanism with PD genetic factors is largely unknown. Here, we used C. elegans, human neuroblastoma cells and murine cortical neurons to determine the role of LRRK2 in maintaining dopaminergic neuron viability. We found that LRRK2 acts to protect neuroblastoma cells and C. elegans dopaminergic neurons from the toxicity of 6-hydroxydopamine and/or human α-synuclein, possibly through the p38 pathway, by supporting upregulation of GRP78, a key cell survival molecule during ER stress. A pathogenic LRRK2 mutant (G2019S), however, caused chronic p38 activation that led to death of murine neurons and age-related dopaminergic-specific neurodegeneration in nematodes. These observations establish a critical functional link between LRRK2 and ER stress.

  3. Protective effects of quercetin on dieldrin-induced endoplasmic reticulum stress and apoptosis in dopaminergic neuronal cells.

    Science.gov (United States)

    Park, Euteum; Chun, Hong Sung

    2016-10-19

    Dieldrin, an organochlorine pesticide still used in several developing countries, has been proposed as a risk factor for Parkinson's disease. Quercetin is one of the potent bioactive flavonoids present in numerous plants. In this study, we investigated the protective effects of quercetin on neurotoxicity induced by dieldrin in cultured dopaminergic SN4741 cells. Our initial experiments showed that quercetin (10-40 μM) dose dependently prevented dieldrin (20 μM)-induced cytotoxicity in SN4741 cells. Pretreatment for 1 h with quercetin before dieldrin application could significantly suppress dieldrin-induced apoptotic characteristics, including nuclear condensation, DNA fragmentation, and caspase-3/7 activation. Results showed that dieldrin-induced markers of endoplasmic reticulum (ER) stress response such as chaperone GRP78, heme oxygenase-1, and phosphorylation of the α subunit of eukaryotic initiation factor 2. In addition, dieldrin reduced antiapoptotic Bcl-2 expression, but significantly elevated a proapoptotic transcription factor CHOP. Furthermore, RNA interference to CHOP almost completely repressed dieldrin-induced apoptotic cell death. Interestingly, quercetin prevented the changes in dieldrin-induced ER stress markers. These results suggest that quercetin may suppress the ER stress-CHOP pathway and dieldrin-induced apoptosis in dopaminergic neurons.

  4. Alcohol Dehydrogenase Protects against Endoplasmic Reticulum Stress-Induced Myocardial Contractile Dysfunction via Attenuation of Oxidative Stress and Autophagy: Role of PTEN-Akt-mTOR Signaling.

    Directory of Open Access Journals (Sweden)

    Jiaojiao Pang

    Full Text Available The endoplasmic reticulum (ER plays an essential role in ensuring proper folding of the newly synthesized proteins. Aberrant ER homeostasis triggers ER stress and development of cardiovascular diseases. ADH is involved in catalyzing ethanol to acetaldehyde although its role in cardiovascular diseases other than ethanol metabolism still remains elusive. This study was designed to examine the impact of ADH on ER stress-induced cardiac anomalies and underlying mechanisms involved using cardiac-specific overexpression of alcohol dehydrogenase (ADH.ADH and wild-type FVB mice were subjected to the ER stress inducer tunicamycin (1 mg/kg, i.p., for 48 hrs. Myocardial mechanical and intracellular Ca(2+ properties, ER stress, autophagy and associated cell signaling molecules were evaluated.ER stress compromised cardiac contractile function (evidenced as reduced fractional shortening, peak shortening, maximal velocity of shortening/relengthening, prolonged relengthening duration and impaired intracellular Ca(2+ homeostasis, oxidative stress and upregulated autophagy (increased LC3B, Atg5, Atg7 and p62, along with dephosphorylation of PTEN, Akt and mTOR, all of which were attenuated by ADH. In vitro study revealed that ER stress-induced cardiomyocyte anomaly was abrogated by ADH overexpression or autophagy inhibition using 3-MA. Interestingly, the beneficial effect of ADH was obliterated by autophagy induction, inhibition of Akt and mTOR. ER stress also promoted phosphorylation of the stress signaling ERK and JNK, the effect of which was unaffected by ADH transgene.Taken together, these findings suggested that ADH protects against ER stress-induced cardiac anomalies possibly via attenuation of oxidative stress and PTEN/Akt/mTOR pathway-regulated autophagy.

  5. Inhibition of soluble epoxide hydrolase attenuates hepatic fibrosis and endoplasmic reticulum stress induced by carbon tetrachloride in mice

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Todd R. [Department of Entomology and Comprehensive Cancer Center, University of California, Davis, CA 95616 (United States); Bettaieb, Ahmed [Department of Nutrition, University of California, Davis, CA 95616 (United States); Kodani, Sean; Dong, Hua [Department of Entomology and Comprehensive Cancer Center, University of California, Davis, CA 95616 (United States); Myers, Richard; Chiamvimonvat, Nipavan [Department of Internal Medicine: Cardiovascular, University of California, Davis, CA 95616 (United States); Haj, Fawaz G. [Department of Nutrition, University of California, Davis, CA 95616 (United States); Department of Internal Medicine: Endocrinology, Diabetes and Metabolism, University of California, Davis, CA 95616 (United States); Hammock, Bruce D., E-mail: bdhammock@ucdavis.edu [Department of Entomology and Comprehensive Cancer Center, University of California, Davis, CA 95616 (United States)

    2015-07-15

    Liver fibrosis is a pathological condition in which chronic inflammation and changes to the extracellular matrix lead to alterations in hepatic tissue architecture and functional degradation of the liver. Inhibitors of the enzyme soluble epoxide hydrolase (sEH) reduce fibrosis in the heart, pancreas and kidney in several disease models. In this study, we assess the effect of sEH inhibition on the development of fibrosis in a carbon tetrachloride (CCl{sub 4})-induced mouse model by monitoring changes in the inflammatory response, matrix remolding and endoplasmic reticulum stress. The sEH inhibitor 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU) was administered in drinking water. Collagen deposition in the liver was increased five-fold in the CCl{sub 4}-treated group, and this was returned to control levels by TPPU treatment. Hepatic expression of Col1a2 and 3a1 mRNA was increased over fifteen-fold in the CCl{sub 4}-treated group relative to the Control group, and this increase was reduced by 50% by TPPU treatment. Endoplasmic reticulum (ER) stress observed in the livers of CCl{sub 4}-treated animals was attenuated by TPPU treatment. In order to support the hypothesis that TPPU is acting to reduce the hepatic fibrosis and ER stress through its action as a sEH inhibitor we used a second sEH inhibitor, trans-4-(4-[3-(4-trifluoromethoxy-phenyl)-ureido]-cyclohexyloxy)-benzoic acid (t-TUCB), and sEH null mice. Taken together, these data indicate that the sEH may play an important role in the development of hepatic fibrosis induced by CCl{sub 4}, presumably by reducing endogenous fatty acid epoxide chemical mediators acting to reduce ER stress. - Highlights: • We administer an inhibitor of sEH in a CCl4 murine model. • sEH inhibition reduces liver collagen deposition and pro-fibrotic gene expression. • sEH inhibition induces MMP-1a activity.

  6. Ethanol metabolism, oxidative stress, and endoplasmic reticulum stress responses in the lungs of hepatic alcohol dehydrogenase deficient deer mice after chronic ethanol feeding.

    Science.gov (United States)

    Kaphalia, Lata; Boroumand, Nahal; Hyunsu, Ju; Kaphalia, Bhupendra S; Calhoun, William J

    2014-06-01

    Consumption and over-consumption of alcoholic beverages are well-recognized contributors to a variety of pulmonary disorders, even in the absence of intoxication. The mechanisms by which alcohol (ethanol) may produce disease include oxidative stress and prolonged endoplasmic reticulum (ER) stress. Many aspects of these processes remain incompletely understood due to a lack of a suitable animal model. Chronic alcohol over-consumption reduces hepatic alcohol dehydrogenase (ADH), the principal canonical metabolic pathway of ethanol oxidation. We therefore modeled this situation using hepatic ADH-deficient deer mice fed 3.5% ethanol daily for 3 months. Blood ethanol concentration was 180 mg% in ethanol fed mice, compared to alcoholic lung disease. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Brucella suis Vaccine Strain 2 Induces Endoplasmic Reticulum Stress that Affects Intracellular Replication in Goat Trophoblast Cells In vitro.

    Science.gov (United States)

    Wang, Xiangguo; Lin, Pengfei; Li, Yang; Xiang, Caixia; Yin, Yanlong; Chen, Zhi; Du, Yue; Zhou, Dong; Jin, Yaping; Wang, Aihua

    2016-01-01

    Brucella has been reported to impair placental trophoblasts, a cellular target where Brucella efficiently replicates in association with the endoplasmic reticulum (ER), and ultimately trigger abortion in pregnant animals. However, the precise effects of Brucella on trophoblast cells remain unclear. Here, we describe the infection and replication of Brucella suis vaccine strain 2 (B.suis.S2) in goat trophoblast cells (GTCs) and the cellular and molecular responses induced in vitro. Our studies demonstrated that B.suis.S2 was able to infect and proliferate to high titers, hamper the proliferation of GTCs and induce apoptosis due to ER stress. Tunicamycin (Tm), a pharmacological chaperone that strongly mounts ER stress-induced apoptosis, inhibited B.suis.S2 replication in GTCs. In addition, 4 phenyl butyric acid (4-PBA), a pharmacological chaperone that alleviates ER stress-induced apoptosis, significantly enhanced B.suis.S2 replication in GTCs. The Unfolded Protein Response (UPR) chaperone molecule GRP78 also promoted B.suis.S2 proliferation in GTCs by inhibiting ER stress-induced apoptosis. We also discovered that the IRE1 pathway, but not the PERK or ATF6 pathway, was activated in the process. However, decreasing the expression of phosphoIRE1α and IRE1α proteins with Irestatin 9389 (IRE1 antagonist) in GTCs did not affect the proliferation of B.suis.S2. Although GTC implantation was not affected upon B.suis.S2 infection, progesterone secretion was suppressed, and prolactin and estrogen secretion increased; these effects were accompanied by changes in the expression of genes encoding key steroidogenic enzymes. This study systematically explored the mechanisms of abortion in Brucella infection from the viewpoint of pathogen invasion, ER stress and reproductive endocrinology. Our findings may provide new insight for understanding the mechanisms involved in goat abortions caused by Brucella infection.

  8. Brucella suis vaccine strain 2 induces endoplasmic reticulum stress that affects intracellular replication in goat trophoblast cells in vitro

    Directory of Open Access Journals (Sweden)

    Xiangguo eWang

    2016-02-01

    Full Text Available Brucella has been reported to impair placental trophoblasts, a cellular target where Brucella efficiently replicates in association with the endoplasmic reticulum (ER, and ultimately trigger abortion in pregnant animals. However, the precise effects of Brucella on trophoblast cells remain unclear. Here, we describe the infection and replication of Brucella suis vaccine strain 2 (B.suis.S2 in goat trophoblast cells (GTCs and the cellular and molecular responses induced in vitro. Our studies demonstrated that B.suis.S2 was able to infect and proliferate to high titers, hamper the proliferation of GTCs and induce apoptosis due to ER stress. Tunicamycin (Tm, a pharmacological chaperone that strongly mounts ER stress-induced apoptosis, inhibited B.suis.S2 replication in GTCs. In addition, 4 phenyl butyric acid (4-PBA, a pharmacological chaperone that alleviates ER stress-induced apoptosis, significantly enhanced B.suis.S2 replication in GTCs. The Unfolded Protein Response (UPR chaperone molecule GRP78 also promoted B.suis.S2 proliferation in GTCs by inhibiting ER stress-induced apoptosis. We also discovered that the IRE1 pathway, but not the PERK or ATF6 pathway, was activated in the process. However, decreasing the expression of phosphoIRE1α and IRE1α proteins with Irestatin 9389 (IRE1 antagonist in GTCs did not affect the proliferation of B.suis.S2. Although GTC implantation was not affected upon B.suis.S2 infection, progesterone secretion was suppressed, and prolactin and estrogen secretion increased; these effects were accompanied by changes in the expression of genes encoding key steroidogenic enzymes. This study systematically explored the mechanisms of abortion in Brucella infection from the viewpoint of pathogen invasion, ER stress and reproductive endocrinology. Our findings may provide new insight for understanding the mechanisms involved in goat abortions caused by Brucella infection.

  9. The endoplasmic reticulum stress inhibitor salubrinal inhibits the activation of autophagy and neuroprotection induced by brain ischemic preconditioning

    Institute of Scientific and Technical Information of China (English)

    Bo GAO; Xiang-yang ZHANG; Rong HAN; Tong-tong ZHANG; Cheng CHEN; Zheng-hong QIN; Rui SHENG

    2013-01-01

    Aim:To investigate whether endoplasmic reticulum (ER) stress participates in the neuroprotective effects of ischemic preconditioning (IPC)-induced neuroprotection and autophagy activation in rat brains.Methods:The right middle cerebral artery in SD rats was occluded for 10 min to induce focal cerebral IPC,and was occluded permanently 24 h later to induce permanent focal ischemia (PFI).ER stress inhibitor salubrinal (SAL) was injected via intracerebral ventricle infusion 10 min before the onset of IPC.Infarct volume and motor behavior deficits were examined after the ischemic insult.The protein levels of LC3,p62,HSP70,glucose-regulated protein 78 (GRP 78),p-elF2α and caspase-12 in the ipsilateral cortex were analyzed using immunoblotting.LC3 expression pattern in the sections of ipsilateral cortex was observed with immunofluorescence.Results:Pretreatment with SAL (150 pmol) abolished the neuroprotective effects of IPC,as evidenced by the significant increases in mortality,infarct volume and motor deficits after PFI.At the molecular levels,pretreatment with SAL (150 pmol) significantly increased p-elF2α level,and decreased GRP78 level after PFI,suggesting that SAL effectively inhibited ER stress in the cortex.Furthermore,the pretreatment with SAL blocked the IPC-induced upregulation of LC3-Ⅱ and downregulation of p62 in the cortex,thus inhibiting the activation of autophagy.Moreover,SAL blocked the upregulation of HSP70,but significantly increased the cleaved caspase-12 level,thus promoting ER stress-dependent apoptotic signaling in the cortex.Conclusion:ER stress-induced autophagy might contribute to the neuroprotective effect of brain ischemic preconditioning.

  10. Differing endoplasmic reticulum stress response to excess lipogenesis versus lipid oversupply in relation to hepatic steatosis and insulin resistance.

    Directory of Open Access Journals (Sweden)

    Lu-Ping Ren

    Full Text Available Mitochondrial dysfunction and endoplasmic reticulum (ER stress have been implicated in hepatic steatosis and insulin resistance. The present study investigated their roles in the development of hepatic steatosis and insulin resistance during de novo lipogenesis (DNL compared to extrahepatic lipid oversupply. Male C57BL/6J mice were fed either a high fructose (HFru or high fat (HFat diet to induce DNL or lipid oversupply in/to the liver. Both HFru and HFat feeding increased hepatic triglyceride within 3 days (by 3.5 and 2.4 fold and the steatosis remained persistent from 1 week onwards (p<0.01 vs Con. Glucose intolerance (iAUC increased by ∼60% and blunted insulin-stimulated hepatic Akt and GSK3β phosphorylation (∼40-60% were found in both feeding conditions (p<0.01 vs Con, assessed after 1 week. No impairment of mitochondrial function was found (oxidation capacity, expression of PGC1α, CPT1, respiratory complexes, enzymatic activity of citrate synthase & β-HAD. As expected, DNL was increased (∼60% in HFru-fed mice and decreased (32% in HFat-fed mice (all p<0.05. Interestingly, associated with the upregulated lipogenic enzymes (ACC, FAS and SCD1, two (PERK/eIF2α and IRE1/XBP1 of three ER stress pathways were significantly activated in HFru-fed mice. However, no significant ER stress was observed in HFat-fed mice during the development of hepatic steatosis. Our findings indicate that HFru and HFat diets can result in hepatic steatosis and insulin resistance without obvious mitochondrial defects via different lipid metabolic pathways. The fact that ER stress is apparent only with HFru feeding suggests that ER stress is involved in DNL per se rather than resulting from hepatic steatosis or insulin resistance.

  11. Different Eukaryotic Initiation Factor Mutations Lead to Various Degrees of Intolerance to the Stress of Endoplasmic Reticulum in Oligodendrocytes

    Institute of Scientific and Technical Information of China (English)

    Na Chen; Yu-Wu Jiang; Hong-Jun Hao; Ting-Ting Ban; Kai Gao; Zhong-Bin Zhang; Jing-Min Wang

    2015-01-01

    Background:Vanishing white matter disease (VWM),a human autosomal recessive inherited leukoencephalopathy,is due to mutations in eukaryotic initiation factor 2B (eIF2B).eIF2B is responsible for the initiation of protein synthesis by its guanine nucleotide exchange factor (GEF) activity.Mutations ofeIF2B impair GEF activity at different degree.Previous studies implied improperly activated unfolded protein response (UPR) and endoplasmic reticulum stress (ERS) participated in the pathogenesis ofVWM.Autophagy relieves endoplasmic reticulum load by eliminating the unfolded protein.It is still unknown the effects of genotypes on the pathogenesis.In this work,UPR and autophagy flux were analyzed with different mutational types.Methods:ERS tolerance,reflected by apoptosis and cell viability,was detected in human oligodendrocyte cell line transfected with the wild type,or different mutations ofp.Arg 113His,p.Arg269* or p.Ser610-Asp613del in eIF2Bε.A representative UPR-PERK component of activating transcription factor 4 (ATF4) was measured under the basal condition and ERS induction.Autophagy was analyzed the flux in the presence of lysosomal inhibitors.Results:The degree of ERS tolerance varied in different genotypes.The truncated or deletion mutant showed prominent apoptosis cell viability declination afder ERS induction.The most seriously damaged GEF activity ofp.Arg269* group underwent spontaneous apoptosis.The truncated or deletion mutant showed elevated ATF4 under basal as well as ERS condition.Decreased expression of LC3-Ⅰ and LC3-Ⅱ in the mutants reflected an impaired autophagy flux,which was more obvious in the truncated or deletion mutants after ERS induction.Conclusions:GEF activities in different genotypes could influence the cell ERS tolerance as well as compensatory pathways of UPR and autophagy.Oligodendrocytes with truncated or deletion mutants showed less tolerable to ERS.

  12. CDIP1-BAP31 complex transduces apoptotic signals from endoplasmic reticulum to mitochondria under ER stress

    OpenAIRE

    Namba, Takushi; Tian, Fang; Chu, Kiki; Hwang, So-Young; Yoon, Kyoung Wan; Byun, Sanguine; Hiraki, Masatsugu; Mandinova, Anna; Lee, Sam W.

    2013-01-01

    Resolved ER stress response is essential for intracellular homeostatic balance, but unsettled ER stress can lead to apoptosis. Here, we show that a pro-apoptotic p53 target, CDIP1, acts as a key signal transducer of ER stress-mediated apoptosis. We identify BAP31, B-cell receptor-associated protein 31, as an interacting partner of CDIP1. Upon ER stress, CDIP1 is induced and enhances an association with BAP31 at the ER membrane. We also show that CDIP1 binding to BAP31 is required for BAP31 cl...

  13. Inhalation of titanium dioxide induces endoplasmic reticulum stress-mediated autophagy and inflammation in mice.

    Science.gov (United States)

    Yu, Kyeong-Nam; Sung, Jae Hyuck; Lee, Somin; Kim, Ji-Eun; Kim, Sanghwa; Cho, Won-Young; Lee, Ah Young; Park, Soo Jin; Lim, Joohyun; Park, Changhoon; Chae, Chanhee; Lee, Jin Kyu; Lee, Jinkyu; Kim, Jun-Sung; Cho, Myung-Haing

    2015-11-01

    Titanium dioxide (TiO2) nanoparticles are widely used in cosmetics, sunscreen, electronics, drug delivery systems, and diverse bio-application fields. In the workplace, the primary exposure route for TiO2 nanoparticles is inhalation through the respiratory system. Because TiO2 nanoparticles have different physiological properties, in terms of size and bioactivity, their toxic effects in the respiratory system must be determined. In this study, to determine the toxic effect of inhaled TiO2 nanoparticles in the lung and the underlying mechanism, we used a whole-body chamber inhalation system to expose A/J mice to TiO2 nanoparticles for 28 days. During the experiments, the inhaled TiO2 nanoparticles were characterized using a cascade impactor and transmission electron microscopy. After inhalation of the TiO2 nanoparticles, hyperplasia and inflammation were observed in a TiO2 dose-dependent manner. To determine the biological mechanism of the toxic response in the lung, we examined endoplasmic reticulum (ER) and mitochondria in lung. The ER and mitochondria were disrupted and dysfunctional in the TiO2-exposed lung leading to abnormal autophagy. In summary, we assessed the potential risk of TiO2 nanoparticles in the respiratory system, which contributed to our understanding of the mechanism underlining TiO2 nanoparticle toxicity in the lung.

  14. Manganese induces endoplasmic reticulum (ER) stress and activates multiple caspases in nigral dopaminergic neuronal cells, SN4741.

    Science.gov (United States)

    Chun, H S; Lee, H; Son, J H

    2001-12-04

    Chronic exposure to manganese causes Parkinson's disease (PD)-like clinical symptoms (Neurotoxicology 5 (1984) 13; Arch. Neurol. 46 (1989) 1104; Neurology 56 (2001) 4). Occupational exposure to manganese is proposed as a risk factor in specific cases of idiopathic PD (Neurology 56 (2001) 8). We have investigated the mechanism of manganese neurotoxicity in nigral dopaminergic (DA) neurons using the DA cell line, SN4741 (J. Neurosci. 19 (1999) 10). Manganese treatment elicited endoplasmic reticulum (ER) stress responses, such as an increased level of the ER chaperone BiP, and simultaneously activated the ER resident caspase-12. Peak activation of other major initiator caspases-like activities, such as caspase-1, -8 and -9, ensued, resulting in activation of caspase-3-like activity during manganese-induced DA cell death. The neurotoxic cell death induced by manganese was significantly reduced in the Bcl-2-overexpressing DA cell lines. Our findings suggest that manganese-induced neurotoxicity is mediated in part by ER stress and considerably ameliorated by Bcl-2 overexpression in DA cells.

  15. Region-specific vulnerability to endoplasmic reticulum stress-induced neuronal death in rat brain after status epilepticus

    Indian Academy of Sciences (India)

    Jing Chen; Hu Guo; Guo Zheng; Zhong-Nan Shi

    2013-12-01

    We sought to clarify the involvement and the intra-cerebral distribution variability of C/EBP homologous protein (CHOP), a representative molecule related to endoplasmic reticulum (ER) stress-induced cell death signalling pathways, in neuronal death resulting from status epilepticus in rats. The expression patterns of CHOP and glucose-regulated protein (GRP) 78, a good marker of ER stress, were assessed by Western blotting, real-time PCR, Hoechst and immunohistochemistry in the hippocampus, cortex and striatum on a status epilepticus (SE) model. Double-fluorescent staining of CHOP and the terminal deoxynucleotidyl transferase-mediated DNA nick-end labelling (TUNEL) method were performed to clarify the involvement of CHOP in cell death. SE resulted in a time-dependent increase in the expression of GRP78 and CHOP. The expression of GRP78 protein was increased at 3, 6 and 12 h after SE and no brain region variability was found. The expression of CHOP protein was also increased, reached its peak at 24 h and remained high at 48 h. CHOP protein expression, however, showed brain region variability with highest expression noted in the hippocampus followed by the striatum, and lowest in the cortex. The up-regulation of CHOP occurring at the transcriptional level was demonstrated by real-time PCR. Double fluorescence showed that CHOP expression strongly correlated with neurons undergoing apoptosis. The results indicated that SE compromises the function of the ER and that the hippocampus is more vulnerable than the cortex and the striatum.

  16. Genes and Gene Networks Involved in Sodium Fluoride-Elicited Cell Death Accompanying Endoplasmic Reticulum Stress in Oral Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Yoshiaki Tabuchi

    2014-05-01

    Full Text Available Here, to understand the molecular mechanisms underlying cell death induced by sodium fluoride (NaF, we analyzed gene expression patterns in rat oral epithelial ROE2 cells exposed to NaF using global-scale microarrays and bioinformatics tools. A relatively high concentration of NaF (2 mM induced cell death concomitant with decreases in mitochondrial membrane potential, chromatin condensation and caspase-3 activation. Using 980 probe sets, we identified 432 up-regulated and 548 down-regulated genes, that were differentially expressed by >2.5-fold in the cells treated with 2 mM of NaF and categorized them into 4 groups by K-means clustering. Ingenuity® pathway analysis revealed several gene networks from gene clusters. The gene networks Up-I and Up-II included many up-regulated genes that were mainly associated with the biological function of induction or prevention of cell death, respectively, such as Atf3, Ddit3 and Fos (for Up-I and Atf4 and Hspa5 (for Up-II. Interestingly, knockdown of Ddit3 and Hspa5 significantly increased and decreased the number of viable cells, respectively. Moreover, several endoplasmic reticulum (ER stress-related genes including, Ddit3, Atf4 and Hapa5, were observed in these gene networks. These findings will provide further insight into the molecular mechanisms of NaF-induced cell death accompanying ER stress in oral epithelial cells.

  17. Inhibition of autophagy by 3-MA enhances endoplasmic reticulum stress-induced apoptosis in human nasopharyngeal carcinoma cells.

    Science.gov (United States)

    Song, Lele; Liu, Hao; Ma, Linyan; Zhang, Xudng; Jiang, Zhiwen; Jiang, Chenchen

    2013-10-01

    Radiotherapy and adjuvant cisplatin chemotherapy are the mainstream treatments for nasopharyngeal carcinoma (NPC), which effectively improve the outcome and reduce tumor recurrence. However, the resistance mechanism(s) involved in radiotherapy and chemotherapy, which is the main barrier in NPC treatment, remains undefined. Therefore, there is an urgent requirement for the identification of new therapeutic strategies or adjuvant drugs. In the present study, the effects of autophagy inhibitors on endoplasmic reticulum (ER) stress-induced autophagy was investigated. Combining 3-methyladenine (3-MA) with cisplatin (DDP), ionizing radiation (IR), 2-deoxy-D-glucose (2-DG) or tunicamycin (TM) resulted in enhanced cell death, as revealed by MTT and colony formation assays. Flow cytometry results demonstrated that the sensitivity of NPC cells to DDP- and IR-induced apoptosis was not significant. DDP, IR, 2-DG and TM induced ER stress and autophagy. Using fluorescence microscopy, 3-MA was identified to increase the apoptotic cell death induced by DDP, IR, 2-DG or TM. In addition, 3-MA inhibited the increased autophagy induced by DDP, IR, 2-DG or TM, as demonstrated by western blot analysis and immunocytochemistry results. Results of the present study indicate that autophagy acts as a protective mechanism response to the apoptosis induced by DDP, IR, 2-DG or TM.

  18. Involvement of the Nrf2-proteasome pathway in the endoplasmic reticulum stress response in pancreatic β-cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sanghwan; Hur, Eu-gene [Yeungnam University, College of Pharmacy, Gyeongsan-si, Gyeongsangbuk-do 712‐749 (Korea, Republic of); Ryoo, In-geun; Jung, Kyeong-Ah [The Catholic University of Korea, College of Pharmacy, Wonmi-gu, Bucheon, Gyeonggi-do 420‐743 (Korea, Republic of); Kwak, Jiyeon [Inha University, College of Medicine, 253 Yonghyun-dong, Nam-gu, Incheon 402‐751 (Korea, Republic of); Kwak, Mi-Kyoung, E-mail: mkwak@catholic.ac.kr [The Catholic University of Korea, College of Pharmacy, Wonmi-gu, Bucheon, Gyeonggi-do 420‐743 (Korea, Republic of)

    2012-11-01

    The ubiquitin-proteasome system plays a central role in protein quality control through endoplasmic reticulum (ER)-associated degradation (ERAD) of unfolded and misfolded proteins. NF-E2‐related factor 2 (Nrf2) is a transcription factor that controls the expression of an array of phase II detoxification and antioxidant genes. Nrf2 signaling has additionally been shown to upregulate the expression of the proteasome catalytic subunits in several cell types. Here, we investigated the role of Nrf2 in tunicamycin-induced ER stress using a murine insulinoma β-cell line, βTC-6. shRNA-mediated silencing of Nrf2 expression in βTC-6 cells significantly increased tunicamycin-induced cytotoxicity, elevated the expression of the pro-apoptotic ER stress marker Chop10, and inhibited tunicamycin-inducible expression of the proteasomal catalytic subunits Psmb5 and Psmb6. The effects of 3H-1,2-dithiole-3-thione (D3T), a small molecule Nrf2 activator, on ER stress were also examined in βTC-6 cells. D3T pretreatment reduced tunicamycin cytotoxicity and attenuated the tunicamycin-inducible Chop10 and protein kinase RNA-activated‐like ER kinase (Perk). The protective effect of D3T was shown to be associated with increased ERAD. D3T increased the expression of Psmb5 and Psmb6 and elevated chymotrypsin-like peptidase activity; proteasome inhibitor treatment blocked D3T effects on tunicamycin cytotoxicity and ER stress marker changes. Similarly, silencing of Nrf2 abolished the protective effect of D3T against ER stress. These results indicate that the Nrf2 pathway contributes to the ER stress response in pancreatic β-cells by enhancing proteasome-mediated ERAD. -- Highlights: ► Nrf2 silencing in pancreatic β-cells enhanced tunicamycin-mediated ER stress. ► Expression of the proteasome was inducible by Nrf2 signaling. ► Nrf2 activator D3T protected β-cells from tunicamycin-mediated ER stress. ► Protective effect of D3T was associated with Nrf2-dependent proteasome

  19. The Effect of Chronic Ozone Exposure on the Activation of Endoplasmic Reticulum Stress and Apoptosis in Rat Hippocampus

    Science.gov (United States)

    Rodríguez-Martínez, Erika; Nava-Ruiz, Concepcion; Escamilla-Chimal, Elsa; Borgonio-Perez, Gabino; Rivas-Arancibia, Selva

    2016-01-01

    The chronic exposure to low doses of ozone, like in environmental pollution, leads to a state of oxidative stress, which has been proposed to contribute to neurodegenerative disorders, including Alzheimer’s disease (AD). It induces an increase of calcium in the endoplasmic reticulum (ER), which produces ER stress. On the other hand, different studies show that, in diseases such as Alzheimer’s, there exist disturbances in protein folding where ER plays an important role. The objective of this study was to evaluate the state of chronic oxidative stress on ER stress and its relationship with apoptotic death in the hippocampus of rats exposed to low doses of ozone. We used 108 male Wistar rats randomly divided into five groups. The groups received one of the following treatments: (1) Control (air); (2) Ozone (O3) 7 days; (3) O3 15 days; (4) O3 30 days; (5) O3 60 days; and (6) O3 90 days. Two hours after each treatment, the animals were sacrificed and the hippocampus was extracted. Afterwards, the tissue was processed for western blot and immunohistochemistry using the following antibodies: ATF6, 78 kDa glucose-regulated protein (GRP78) and caspase 12. It was also subjected to terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and electronic microscopy. Our results show an increase in ATF6, GRP78 and caspase 12 as well as ER ultrastructural alterations and an increase of TUNEL positive cells after 60 and 90 days of exposure to ozone. With the obtained results, we can conclude that oxidative stress induced by chronic exposure to low doses of ozone leads to ER stress. ER stress activates ATF6 inducing the increase of GRP78 in the cytoplasm, which leads to the increase in the nuclear translocation of ATF6. Finally, the translocation creates a vicious cycle that, together with the activation of the cascade for apoptotic cell death, contributes to the maintenance of ER stress. These events potentially contribute in the neurodegeneration processes

  20. Endoplasmic reticulum stress and Nrf2 repression in circulating cells of type 2 diabetic patients without the recommended glycemic goals.

    Science.gov (United States)

    Mozzini, C; Garbin, U; Stranieri, C; Pasini, A; Solani, E; Tinelli, I A; Cominacini, L; Fratta Pasini, A M

    2015-03-01

    Endoplasmic reticulum (ER) stress plays a role in the pathogenesis of type 2 diabetes mellitus (T2DM), with activation of the unfolded protein response (UPR) and ER apoptosis in β-cells. The aim of the study is investigating the role of the prolonged glycemic, inflammatory, and oxidative impairment as possible UPR and ER apoptosis inductors in triggering the ER stress response and the protective nuclear erythroid-related factor 2 (Nrf2)/antioxidant-related element (ARE) activation in peripheral blood mononuclear cells (PBMC) of T2DM patients without glycemic target. Oxidative stress markers (oxidation product of phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine [oxPAPC], and malondialdehyde [MDA]), the UPR and ER apoptosis, the activation of the pro-inflammatory nuclear factor-kappa B (NF-kB) with its inhibitory protein inhibitor-kBα, and the expression of the protective Nrf2 and heme oxygenase-1 (HO-1) were evaluated in PBMC of 15 T2DM patients and 15 healthy controls (C). OxPAPC concentrations (in PBMC and plasma), MDA levels (in plasma), the expressions of the glucose-regulated protein 78 kDa (or BiP) as representative of UPR, and of the CCAAT/enhancer-binding protein homologous protein as representative of ER apoptosis were significantly higher (p glycemic target achievement, there is an activation of the UPR and of the ER apoptosis, which may be related to the chronic exposure to hyperglycemia, to the augmented inflammation, and to the augmented oxidative stress, without a corresponding Nrf2/ARE defense activation.

  1. Human Melanoma Cells under Endoplasmic Reticulum Stress Are More Susceptible to Apoptosis Induced by the BH3 Mimetic Obatoclax

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    Chen Chen Jiang

    2009-09-01

    Full Text Available Past studies have shown that melanoma cells have largely adapted to endoplasmic reticulum (ER stress, and this is associated with up-regulation of the antiapoptotic proteins Bcl-2 and Mcl-1. In this report, we show that the BH3 mimetic obatoclax potently overcomes resistance of melanoma cells to apoptosis induced by ER stress. Obatoclax, as a single agent at nanomolar concentrations, was relatively ineffective in the induction of apoptosis in melanoma cells, but treatment with obatoclax at these concentrations in combination with the ER stress inducer tunicamycin (TM or thapsigargin markedly enhanced apoptotic cell death. This was primarily because of the inhibition of Mcl-1 by obatoclax, in that cotreatment with TM and another BH3 mimetic ABT737, which does not antagonize Mcl-1, caused only minimal increases in apoptosis. Moreover, overexpression of Mcl-1 inhibited apoptosis to greater degrees than overexpression of Bcl-2. In addition to direct inhibition of Mcl-1 by obatoclax, the combination of obatoclax and TM caused strong up-regulation of the BH3-only protein Noxa. Small RNA interference knockdown of Noxa partially inhibited apoptosis induced by cotreatment with obatoclax and TM. Similarly, knockdown of Bak also blocked induction of apoptosis by the compounds. The Mcl-1/Bak interaction seemed to be disrupted more efficiently in melanoma cells cotreated with obatoclax and TM. Taken together, these results identify obatoclax as a potent agent that overcomes resistance of melanoma cells to ER stress-induced apoptosis and seem to have important implications in the use of BH3 mimetics in the treatment of melanoma.

  2. The Cataract-linked Mutant Connexin50D47A Causes Endoplasmic Reticulum Stress in Mouse Lenses.

    Science.gov (United States)

    Berthoud, Viviana M; Minogue, Peter J; Lambert, Paul A; Snabb, Joseph I; Beyer, Eric C

    2016-08-19

    Mice expressing connexin50D47A (Cx50D47A) exhibit nuclear cataracts and impaired differentiation. Cx50D47A does not traffic properly, and homozygous mutant lenses show increased levels of the stress-responsive αB-crystallins. Therefore, we assessed whether expression of Cx50D47A led to endoplasmic reticulum (ER) stress in the lens in vivo Although pharmacologic induction of ER stress can be transduced by three different pathways, we found no evidence for activation of the IRE1α or ATF6 pathways in Cx50D47A-expressing lenses. In contrast, heterozygous and homozygous Cx50D47A lenses showed an increase in phosphorylated PERK immunoreactivity and in the ratio of phosphorylated to total EIF2α (2.4- and 3.3-fold, respectively) compared with wild type. Levels of ATF4 were similar in wild type and heterozygous lenses but elevated in homozygotes (391%). In both heterozygotes and homozygotes, levels of calreticulin protein were increased (184 and 262%, respectively), as was Chop mRNA (1.9- and 12.4-fold, respectively). CHOP protein was increased in homozygotes (384%). TUNEL staining was increased in Cx50D47A lenses, especially in homozygous mice. Levels of two factors that may be pro-survival, Irs2 and Trib3, were greatly increased in homozygous lenses. These results suggest that expression of Cx50D47A induces ER stress, triggering activation of the PERK-ATF4 pathway, which potentially contributes to the lens pathology and leads to increased expression of anti-apoptotic factors, allowing cell survival.

  3. Silica nanoparticles mediated neuronal cell death in corpus striatum of rat brain: implication of mitochondrial, endoplasmic reticulum and oxidative stress

    Science.gov (United States)

    Parveen, Arshiya; Rizvi, Syed Husain Mustafa; Mahdi, Farzana; Tripathi, Sandeep; Ahmad, Iqbal; Shukla, Rajendra K.; Khanna, Vinay K.; Singh, Ranjana; Patel, Devendra K.; Mahdi, Abbas Ali

    2014-11-01

    Extensive uses of silica nanoparticles (SiNPs) in biomedical and industrial fields have increased the risk of exposure, resulting concerns about their safety. We focussed on some of the safety aspects by studying neurobehavioural impairment, oxidative stress (OS), neurochemical and ultrastructural changes in corpus striatum (CS) of male Wistar rats exposed to 80-nm SiNPs. Moreover, its role in inducing mitochondrial and endoplasmic reticulum (ER) stress-mediated neuronal apoptosis was also investigated. The results demonstrated impairment in neurobehavioural indices, and a significant increase in lipid peroxide levels (LPO), hydrogen peroxide (H2O2), superoxide (O2 -) and protein carbonyl content, whereas there was a significant decrease in the activities of the enzymes, manganese superoxide dismutase (Mn SOD), glutathione peroxidase (GPx), catalase (CAT) and reduced glutathione (GSH) content, suggesting impaired antioxidant defence system. Protein (cytochrome c, Bcl-2, Bax, p53, caspase-3, caspase 12 and CHOP/Gadd153) and mRNA (Bcl-2, Bax, p53 and CHOP/Gadd153, cytochrome c) expression studies of mitochondrial and ER stress-related apoptotic factors suggested that both the cell organelles were involved in OS-mediated apoptosis in treated rat brain CS. Moreover, electron microscopic studies clearly showed mitochondrial and ER dysfunction. In conclusion, the result of the study suggested that subchronic SiNPs' exposure has the potential to alter the behavioural activity and also to bring about changes in biochemical, neurochemical and ultrastructural profiles in CS region of rat brain. Furthermore, we also report SiNPs-induced apoptosis in CS, through mitochondrial and ER stress-mediated signalling.

  4. HERP Binds TBK1 To Activate Innate Immunity and Repress Virus Replication in Response to Endoplasmic Reticulum Stress.

    Science.gov (United States)

    Ge, Maolin; Luo, Zhen; Qiao, Zhi; Zhou, Yao; Cheng, Xin; Geng, Qibin; Cai, Yanyan; Wan, Pin; Xiong, Ying; Liu, Fang; Wu, Kailang; Liu, Yingle; Wu, Jianguo

    2017-09-27

    Host innate immunity is crucial for cellular responses against viral infection sensed by distinct pattern recognition receptors and endoplasmic reticulum (ER) stress. Enterovirus 71 (EV71) is a causative agent of hand, foot, and mouth disease and neurological diseases. However, the exact mechanism underlying the link between ER stress induced by EV71 infection and host innate immunity is largely unknown. In this study, we demonstrated that EV71 infection induces the homocysteine-induced ER protein (HERP), a modulator of the ER stress response which is dependent on the participation of MAVS. Virus-induced HERP subsequently stimulates host innate immunity to repress viral replication by promoting type-I IFNs (IFN-α and IFN-β) and type-III IFN (IFN-λ1) expression. Through interacting with TANK-binding kinase 1, HERP amplifies the MAVS signaling and facilitates the phosphorylation and nuclear translocation of IFN regulatory factor 3 and NF-κB to enhance the expression of IFNs, which leads to a broad inhibition of the replication of RNA viruses, including EV71, Sendai virus, influenza A virus, and vesicular stomatitis virus. Therefore, we demonstrated that HERP plays an important role in the regulation of host innate immunity in response to ER stress during the infection of RNA viruses. These findings provide new insights into the mechanism underlying the replication of RNA viruses and the production of IFNs, and also demonstrate a new role of HERP in the regulation of host innate immunity in response to viral infection. Copyright © 2017 by The American Association of Immunologists, Inc.

  5. Three dimensional stress vector sensor array and method therefor

    Science.gov (United States)

    Pfeifer, Kent Bryant; Rudnick, Thomas Jeffery

    2005-07-05

    A sensor array is configured based upon capacitive sensor techniques to measure stresses at various positions in a sheet simultaneously and allow a stress map to be obtained in near real-time. The device consists of single capacitive elements applied in a one or two dimensional array to measure the distribution of stresses across a mat surface in real-time as a function of position for manufacturing and test applications. In-plane and normal stresses in rolling bodies such as tires may thus be monitored.

  6. Cantilever surface stress sensors with single-crystalline silicon piezoresistors

    DEFF Research Database (Denmark)

    Rasmussen, Peter Andreas; Hansen, Ole; Boisen, Anja

    2005-01-01

    on cantilever sensors with integrated piezoresistive readout, that one finds between typical atomic force microscopy measurements and the surface stress sensors used in, e.g., biochemical measurements. We have simulated the response from piezoresistive cantilevers as a function of resistor type and placement...

  7. Unraveling the cellular response to oxidative stress in the endoplasmic reticulum

    DEFF Research Database (Denmark)

    Hansen, Henning Gram

    disulfide bond formation. In conclusion, the results presented here suggest that Ero1-generated hydrogen peroxide is efficiently detoxified in the ER, and this work therefore provides novel insights into the intimate relationship between oxidative protein folding and oxidative stress....

  8. Endoplasmic reticulum stress is increased in adipose tissue of women with gestational diabetes.

    Directory of Open Access Journals (Sweden)

    Stella Liong

    Full Text Available Maternal obesity and gestational diabetes mellitus (GDM are two increasingly common and important obstetric complications that are associated with severe long-term health risks to mothers and babies. IL-1β, which is increased in obese and GDM pregnancies, plays an important role in the pathophysiology of these two pregnancy complications. In non-pregnant tissues, endoplasmic (ER stress is increased in diabetes and can induce IL-1β via inflammasome activation. The aim of this study was to determine whether ER stress is increased in omental adipose tissue of women with GDM, and if ER stress can also upregulate inflammasome-dependent secretion of IL-1β. ER stress markers IRE1α, GRP78 and XBP-1s were significantly increased in adipose tissue of obese compared to lean pregnant women. ER stress was also increased in adipose tissue of women with GDM compared to BMI-matched normal glucose tolerant (NGT women. Thapsigargin, an ER stress activator, induced upregulated secretion of mature IL-1α and IL-1β in human omental adipose tissue explants primed with bacterial endotoxin LPS, the viral dsRNA analogue poly(I:C or the pro-inflammatory cytokine TNF-α. Inhibition of capase-1 with Ac-YVAD-CHO resulted in decreased IL-1α and IL-1β secretion, whereas inhibition of pannexin-1 with carbenoxolone suppressed IL-1β secretion only. Treatment with anti-diabetic drugs metformin and glibenclamide also reduced IL-1α and IL-1β secretion in infection and cytokine-primed adipose tissue. In conclusion, this study has demonstrated ER stress to activate the inflammasome in pregnant adipose tissue. Therefore, increased ER stress may contribute towards the pathophysiology of obesity in pregnancy and GDM.

  9. Inhibition of endoplasmic reticulum stress signaling pathway: A new mechanism of statins to suppress the development of abdominal aortic aneurysm

    Science.gov (United States)

    Li, Yuanyuan; Lu, Gangsheng; Sun, Dating; Zuo, Houjuan; Wang, Dao Wen; Yan, Jiangtao

    2017-01-01

    Background Abdominal aortic aneurysm (AAA) is a potentially lethal disease with extremely poor survival rates once the aneurysm ruptures. Statins may exert beneficial effects on the progression of AAA. However, the underlying mechanism is still not known. The purpose of the present study is to investigate whether statin could inhibit AAA formation by inhibiting the endoplasmic reticulum (ER) stress signal pathway. Methods A clinically relevant AAA model was induced in Apolipoprotein E-deficient (ApoE−/−) mice, which were infused with angiotensin II (Ang II) for 28 days. These mice were randomly divided into following 4 groups: saline infusion alone; Ang II infusion alone; Ang II infusion plus Atorvastatin (20mg/kg/d); and Ang II infusion plus Atorvastatin (30mg/kg/d). Besides, another AAA model was induced in C57 mice with extraluminal CaCl2, which were divided into 3 groups: sham group, CaCl2-induced AAA group, and CaCl2-induced AAA plus atorvastatin (20mg/kg/d) group. Then, aortic tissue was excised for further examinations, respectively. In vitro studies, Ang II with or without simvastatin treatment were applied to the vascular smooth muscle cells (VSMCS) and Raw 264.7 cells. The ER stress signal pathway, apoptosis and inflammatory response were evaluated by in vivo and in vitro assays. Results We found that higher dose of atorvastatin can effectively suppress the development and progression of AAA induced by Ang II or CaCl2. Mechanistically, the activation of ER stress and inflammatory response were found involved in Ang II-induced AAA formation. The atorvastatin infusion significantly reduced ER stress signaling proteins, the number of apoptotic cells, and the activation of Caspase12 and Bax in the Ang II-induced ApoE−/− mice, compared with mice treated by Ang II alone. Furthermore, proinflammatory cytokines such as IL-6, IL-8, IL-1β were all remarkably inhibited after atorvastatin treatment. In vitro, the inhibitory effect of simvastatin on the ER

  10. Endoplasmic reticulum stress involved in high-fat diet and palmitic acid-induced vascular damages and fenofibrate intervention

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yunxia, E-mail: wwwdluyx@sina.com [Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032 (China); The Comprehensive Laboratory, Anhui Medical University, Hefei, Anhui 230032 (China); Cheng, Jingjing [Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032 (China); Chen, Li [Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032 (China); Department of Medical Laboratory, Anhui Provincial Hospital, Hefei, Anhui 230001 (China); Li, Chaofei; Chen, Guanjun [Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032 (China); Gui, Li [The Comprehensive Laboratory, Anhui Medical University, Hefei, Anhui 230032 (China); Shen, Bing [Department of Physiology, Anhui Medical University, Hefei, Anhui 230032 (China); Zhang, Qiu [Department of Endocrinology, First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022 (China)

    2015-02-27

    Fenofibrate (FF) is widely used to lower blood lipids in clinical practice, but whether its protective effect on endothelium-dependent vasodilatation (EDV) in thoracic aorta is related with endoplasmic reticulum (ER) stress remains unknown. In this study, female Sprauge Dawley rats were divided into standard chow diets (SCD), high-fat diets (HFD) and HFD plus FF treatment group (HFD + FF) randomly. The rats of latter two groups were given HFD feeding for 5 months, then HFD + FF rats were treated with FF (30 mg/kg, once daily) via gavage for another 2 months. The pathological and tensional changes, protein expression of eNOS, and ER stress related genes in thoracic aorta were measured. Then impacts of palmitic acid (PA) and FF on EDV of thoracic aorta from normal female SD rats were observed. Ultimately the expression of ER stress related genes were assessed in primary mouse aortic endothelial cells (MAEC) treated by fenofibric acid (FA) and PA. We found that FF treatment improved serum lipid levels and pathological changes in thoracic aorta, accompanied with decreased ER stress and increased phosphorylation of eNOS. FF pretreatment also improved EDV impaired by different concentrations of PA treatment. The dose- and time-dependent inhibition of cell proliferation by PA were inverted by FA pretreatment. Phosphorylation of eNOS and expression of ER stress related genes were all inverted by FA pretreatment in PA-treated MAEC. Our findings show that fenofibrate recovers damaged EDV by chronic HFD feeding and acute stimulation of PA, this effect is related with decreased ER stress and increased phosphorylation of eNOS. - Highlights: • Fenofibrate treatment improved pathological changes in thoracic aorta by chronic high-fat-diet feeding. • Fenofibrate pretreatment improved endothelium-dependent vasodilation impaired by different concentrations of palmitic acid. • The inhibition of proliferation in endothelial cells by palmitic acid were inverted by fenofibric

  11. Analysis of the role of nerve growth factor in promoting cell survival during endoplasmic reticulum stress in PC12 cells.

    Science.gov (United States)

    Shimoke, Koji; Sasaya, Harue; Ikeuchi, Toshihiko

    2011-01-01

    Nerve growth factor (NGF) was first described by Rita Levi-Montalcini in the early 1960s from her studies of peripheral neurons. It has since been reported that NGF has the potential to elongate neurites or to prevent apoptosis via specific intracellular mechanisms. It has further been reported that as a component of these mechanisms, NGF binds to a specific receptor, TrkA, and thereby contributes to peripheral nerve cell functions or neuronal functions. It is noteworthy in this regard that pheochromocytoma 12 (PC12) cells express TrkA and respond to neurite outgrowth or anti-apoptotic signals by binding to NGF. Hence, PC12 cells have been used as an in vitro model system for the study of neuronal functions. It has been reported that endoplasmic reticulum (ER) stress is involved in neurodegenerative disorders, including Alzheimer's, Parkinson's, and Huntington's disease. The common link with regard to ER stress is that the neuronal cells die in these pathologies via specific intracellular mechanisms. This type of cell death, if it is apoptotic in nature, is termed ER stress-mediated apoptosis. In the process of ER stress-mediated apoptosis, the cleavage of pro-caspase-12 residing on the ER and the expression of glucose-regulated protein 78 (GRP78) can be observed. The expression of GRP78 protein is a characteristic of an unfolded protein response (UPR) via specific signal transduction pathways mediated by the unfolded protein response element (UPRE) in the upstream region of the grp78 gene so on. In ER stress-mediated apoptosis, a caspase cascade is also observed. To further clarify the mechanisms underlying ER stress-mediated apoptosis, a better understanding of the UPR is therefore important. In our current study, we describe a method for detecting gene induction via the UPR, focusing on GRP78 and caspase activities as the measurement end-points. The information generated by our method will accelerate our understanding of the pathophysiological processes leading

  12. Chronic restraint stress promotes learning and memory impairment due to enhanced neuronal endoplasmic reticulum stress in the frontal cortex and hippocampus in male mice.

    Science.gov (United States)

    Huang, Rong-Rong; Hu, Wen; Yin, Yan-Yan; Wang, Yu-Chan; Li, Wei-Ping; Li, Wei-Zu

    2015-02-01

    Chronic stress has been implicated in many types of neurodegenerative diseases, such as Alzheimer's disease (AD). In our previous study, we demonstrated that chronic restraint stress (CRS) induced reactive oxygen species (ROS) overproduction and oxidative damage in the frontal cortex and hippocampus in mice. In the present study, we investigated the effects of CRS (over a period of 8 weeks) on learning and memory impairment and endoplasmic reticulum (ER) stress in the frontal cortex and hippocampus in male mice. The Morris water maze was used to investigate the effects of CRS on learning and memory impairment. Immunohistochemistry and immunoblot analysis were also used to determine the expression levels of protein kinase C α (PKCα), 78 kDa glucose-regulated protein (GRP78), C/EBP-homologous protein (CHOP) and mesencephalic astrocyte-derived neurotrophic factor (MANF). The results revealed that CRS significantly accelerated learning and memory impairment, and induced neuronal damage in the frontal cortex and hippocampus CA1 region. Moreover, CRS significantly increased the expression of PKCα, CHOP and MANF, and decreased that of GRP78 in the frontal cortex and hippocampus. Our data suggest that exposure to CRS (for 8 weeks) significantly accelerates learning and memory impairment, and the mechanisms involved may be related to ER stress in the frontal cortex and hippocampus.

  13. Inhibition of GADD34, the stress-inducible regulatory subunit of the endoplasmic reticulum stress response, does not enhance functional recovery after spinal cord injury.

    Directory of Open Access Journals (Sweden)

    Sujata Saraswat Ohri

    Full Text Available Activation of the endoplasmic reticulum stress response (ERSR is a hallmark of various pathological diseases and/or traumatic injuries. Restoration of ER homeostasis can contribute to improvement in the functional outcome of these diseases. Using genetic and pharmacological inhibition of the PERK-CHOP arm of the ERSR, we recently demonstrated improvements in hindlimb locomotion after spinal cord injury (SCI and implicated oligodendrocyte survival as a potential mechanism. Here, we investigated the contribution of stress-inducible PPP1R15A/GADD34, an ERSR signaling effector downstream of CHOP that dephosphorylates eIF2α, in the pathogenesis of SCI. We show that although genetic ablation of GADD34 protects oligodendrocyte precursor cells (OPCs against ER stress-mediated cell death in vitro and results in differential ERSR attenuation in vivo after SCI, there is no improvement in hindlimb locomotor function. Guanabenz, a FDA approved antihypertensive drug, was recently shown to reduce the burden of misfolded proteins in the ER by directly targeting GADD34. Guanabenz protected OPCs from ER stress-mediated cell death in vitro and attenuated the ERSR in vivo after SCI. However, guanabenz administration failed to rescue the locomotor deficits after SCI. These data suggest that deletion of GADD34 alone is not sufficient to improve functional recovery after SCI.

  14. Calreticulin is a fine tuning molecule in epibrassinolide-induced apoptosis through activating endoplasmic reticulum stress in colon cancer cells.

    Science.gov (United States)

    Obakan-Yerlikaya, Pinar; Arisan, Elif Damla; Coker-Gurkan, Ajda; Adacan, Kaan; Ozbey, Utku; Somuncu, Berna; Baran, Didem; Palavan-Unsal, Narcin

    2017-06-01

    Epibrassinolide (EBR), a member of brassinostreoids plant hormones with cell proliferation promoting role in plants, is a natural polyhydroxysteroid with structural similarity to steroid hormones of vertebrates. EBR has antiproliferative and apoptosis-inducing effect in various cancer cells. Although EBR has been shown to affect survival and mitochondria-mediated apoptosis pathways in a p53-independent manner, the exact molecular targets of EBR are still under investigation. Our recent SILAC (Stable Isotope Labeling by Amino Acids in Cell Culture) data showed that the most significantly altered protein after EBR treatment was calreticulin (CALR). CALR, a chaperone localized in endoplasmic reticulum (ER) lumen, plays role in protein folding and buffering Ca(2+) ions. The alteration of CALR may cause ER stress and unfolded protein response correspondingly the induction of apoptosis. Unfolded proteins are conducted to 26S proteasomal degradation following ubiquitination. Our study revealed that EBR treatment caused ER stress and UPR by altering CALR expression causing caspase-dependent apoptosis in HCT 116, HT29, DLD-1, and SW480 colon cancer cells. Furthermore, 48 h EBR treatment did not caused UPR in Fetal Human Colon cells (FHC) and Mouse Embryonic Fibroblast cells (MEF). In addition our findings showed that HCT 116 colon cancer cells lacking Bax and Puma expression still undergo UPR and related apoptosis. CALR silencing and rapamycin co-treatment prevented EBR-induced UPR and apoptosis, whereas 26S proteasome inhibition further increased the effect of EBR in colon cancer cells. All these findings showed that EBR is an ER stress and apoptotic inducer in colon cancer cells without affecting non-malignant cells. © 2017 Wiley Periodicals, Inc.

  15. Expression of hereditary hemochromatosis C282Y HFE protein in HEK293 cells activates specific endoplasmic reticulum stress responses

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    Norris Suzanne

    2007-07-01

    Full Text Available Abstract Background Hereditary Hemochromatosis (HH is a genetic disease associated with iron overload, in which individuals homozygous for the mutant C282Y HFE associated allele are at risk for the development of a range of disorders particularly liver disease. Conformational diseases are a class of disorders associated with the expression of misfolded protein. HFE C282Y is a mutant protein that does not fold correctly and consequently is retained in the Endoplasmic Reticulum (ER. In this context, we sought to identify ER stress signals associated with mutant C282Y HFE protein expression, which may have a role in the molecular pathogenesis of HH. Results Vector constructs of Wild type HFE and Mutant C282Y HFE were made and transfected into HEK293 cell lines. We have shown that expression of C282Y HFE protein triggers both an unfolded protein response (UPR, as revealed by the increased GRP78, ATF6 and CHOP expression, and an ER overload response (EOR, as indicated by NF-κB activation. Furthermore, C282Y HFE protein induced apoptotic responses associated with activation of ER stress. Inhibition studies demonstrated that tauroursodeoxycholic acid, an endogenous bile acid, downregulates these events. Finally, we found that the co-existence of both C282Y HFE and Z alpha 1-antitrypsin protein (the protein associated with the liver disease of Z alpha 1-antitrypsin deficiency expression on ER stress responses acted as potential disease modifiers with respect to each other. Conclusion Our novel observations suggest that both the ER overload response (EOR and the unfolded protein response (UPR are activated by mutant C282Y HFE protein.

  16. Glucose deprivation induces reticulum stress by the PERK pathway and caspase-7- and calpain-mediated caspase-12 activation.

    Science.gov (United States)

    de la Cadena, Selene García; Hernández-Fonseca, Karla; Camacho-Arroyo, Ignacio; Massieu, Lourdes

    2014-03-01

    Glucose is the main energy source in brain and it is critical for correct brain functioning. Type 1 diabetic patients might suffer from severe hypoglycemia if exceeding insulin administration, which can lead to acute brain injury if not opportunely corrected. The mechanisms leading to hypoglycemic brain damage are not completely understood and the role of endoplasmic reticulum (ER) stress has not been studied. ER stress resulting from the accumulation of unfolded or misfolded proteins in the ER is counteracted by the unfolded protein response (UPR). When the UPR is sustained, apoptotic death might take place. We have examined UPR activation during glucose deprivation (GD) in hippocampal cultured neurons and its role in the induction of apoptosis. Activation of the PERK pathway of the UPR was observed, as increased phosphorylation of eIF2α and elevated levels of the transcription factor ATF4, occurred 30 min after GD and the levels of the chaperone protein, GRP78 and the transcription factor CHOP, increased after 2 h of GD. In addition, we observed an early activation of caspase-7 and 12 during GD, while caspase-3 activity increased only transiently during glucose reintroduction. Inhibition of caspase-3/7 and the calcium-dependent protease, calpain, significantly decreased caspase-12 activity. The ER stress inhibitor, salubrinal prevented neuronal death and caspase-12 activity. Results suggest that the PERK pathway of the UPR is involved in GD-induced apoptotic neuronal death through the activation of caspase-12, rather than the mitochondrial-dependent caspase pathway. In addition, we show that calpain and caspase-7 are soon activated after GD and mediate caspase-12 activation and neuronal death.

  17. Activation of PPARα ameliorates hepatic insulin resistance and steatosis in high fructose-fed mice despite increased endoplasmic reticulum stress.

    Science.gov (United States)

    Chan, Stanley M H; Sun, Ruo-Qiong; Zeng, Xiao-Yi; Choong, Zi-Heng; Wang, Hao; Watt, Matthew J; Ye, Ji-Ming

    2013-06-01

    Endoplasmic reticulum (ER) stress is suggested to cause hepatic insulin resistance by increasing de novo lipogenesis (DNL) and directly interfering with insulin signaling through the activation of the c-Jun N-terminal kinase (JNK) and IκB kinase (IKK) pathway. The current study interrogated these two proposed mechanisms in a mouse model of hepatic insulin resistance induced by a high fructose (HFru) diet with the treatment of fenofibrate (FB) 100 mg/kg/day, a peroxisome proliferator-activated receptor α (PPARα) agonist known to reduce lipid accumulation while maintaining elevated DNL in the liver. FB administration completely corrected HFru-induced glucose intolerance, hepatic steatosis, and the impaired hepatic insulin signaling (pAkt and pGSK3β). Of note, both the IRE1/XBP1 and PERK/eIF2α arms of unfolded protein response (UPR) signaling were activated. While retaining the elevated DNL (indicated by the upregulation of SREBP1c, ACC, FAS, and SCD1 and [3H]H2O incorporation into lipids), FB treatment markedly increased fatty acid oxidation (indicated by induction of ACOX1, p-ACC, β-HAD activity, and [14C]palmitate oxidation) and eliminated the accumulation of diacylglycerols (DAGs), which is known to have an impact on insulin signaling. Despite the marked activation of UPR signaling, neither JNK nor IKK appeared to be activated. These findings suggest that lipid accumulation (mainly DAGs), rather than the activation of JNK or IKK, is pivotal for ER stress to cause hepatic insulin resistance. Therefore, by reducing the accumulation of deleterious lipids, activation of PPARα can ameliorate hepatic insulin resistance against increased ER stress.

  18. Endoplasmic Reticulum Stress in the β-Cell Pathogenesis of Type 2 Diabetes

    Directory of Open Access Journals (Sweden)

    Sung Hoon Back

    2012-01-01

    Full Text Available Type 2 diabetes is a complex metabolic disorder characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency by β-cell failure. Even if the mechanisms underlying the pathogenesis of β-cell failure are still under investigation, recent increasing genetic, experimental, and clinical evidence indicate that hyperactivation of the unfolded protein response (UPR to counteract metabolic stresses is closely related to β-cell dysfunction and apoptosis. Signaling pathways of the UPR are “a double-edged sword” that can promote adaptation or apoptosis depending on the nature of the ER stress condition. In this paper, we summarized our current understanding of the mechanisms and components related to ER stress in the β-cell pathogenesis of type 2 diabetes.

  19. Cigarette smoke induces endoplasmic reticulum stress response and proteasomal dysfunction in human alveolar epithelial cells

    NARCIS (Netherlands)

    Somborac-Bacura, Anita; van der Toorn, Marco; Franciosi, Lorenza; Slebos, Dirk-Jan; Zanic-Grubisic, Tihana; Bischoff, Rainer; van Oosterhout, Antoon J. M.

    2013-01-01

    Cigarette smoking is the major risk factor for chronic obstructive pulmonary disease. Cigarette smoke (CS) causes oxidative stress and severe damage to proteins in the lungs. One of the main systems to protect cells from the accumulation of damaged proteins is the ubiquitin-proteasome pathway. In th

  20. Endoplasmic reticulum proteins are major targets of oxidative stress. Application of a novel fluorescent probe

    NARCIS (Netherlands)

    Vlies, Dennis van der

    2003-01-01

    A target for protein oxidation by reactive oxygen species (ROS) is tyrosine, which may form the age- and/or disease-related biomarkers dityrosine, chlorotyrosine and nitrotyrosine. It was already recognized that immunochemical assays should facilitate studies on the role of oxidative stress in aging

  1. Taurine protects cisplatin induced cardiotoxicity by modulating inflammatory and endoplasmic reticulum stress responses.

    Science.gov (United States)

    Chowdhury, Sayantani; Sinha, Krishnendu; Banerjee, Sharmistha; Sil, Parames C

    2016-11-12

    Oxidative stress, ER stress, inflammation, and apoptosis results in the pathogenesis of cisplatin-induced cardiotoxicity. The present study was designed to investigate the signaling mechanisms involved in the ameliorating effect of taurine, a conditionally essential amino acid, against cisplatin-mediated cardiac ER stress dependent apoptotic death and inflammation. Mice were simultaneously treated with taurine (150 mg kg(-1) body wt, i.p.) and cisplatin (10 mg kg(-1) body wt, i.p.) for a week. Cisplatin exposure significantly altered serum creatine kinase and troponin T levels. In addition, histological studies revealed disintegration in the normal radiation pattern of cardiac muscle fibers. However, taurine administration could abate such adverse effects of cisplatin. Taurine administration significantly mitigated the reactive oxygen species production, alleviated the overexpression of nuclear factor-κB (NF-κB), and inhibited the elevation of proinflammatoy cytokines, adhesion molecules, and chemokines. Cisplatin exposure resulted in the unfolded protein response (UPR)-regulated CCAAT/enhancer binding protein (CHOP) up-regulation, induction of GRP78: a marker of ER stress and eIF2α signaling. Increase in calpain-1 expression level, activation of caspase-12 and caspase-3, cleavage of the PARP protein as well as the inhibition of antiapoptotic protein Bcl-2 were reflected on cisplatin-triggered apoptosis. Taurine could, however, combat against such cisplatin induced cardiac-abnormalities. The above mentioned findings suggest that taurine plays a beneficial role in providing protection against cisplatin-induced cardiac damage by modulating inflammatory responses and ER stress. © 2016 BioFactors, 42(6):647-664, 2016. © 2016 International Union of Biochemistry and Molecular Biology.

  2. Oxidative stress induces monocyte necrosis with enrichment of cell-bound albumin and overexpression of endoplasmic reticulum and mitochondrial chaperones.

    Directory of Open Access Journals (Sweden)

    Haiping Tang

    Full Text Available In the present study, monocytes were treated with 5-azacytidine (azacytidine, gossypol or hydrogen peroxide to induce cell death through oxidative stress. A shift from apoptotic to necrotic cell death occurred when monocytes were treated with 100 µM azacytidine for more than 12 hours. Necrotic monocytes exhibited characteristics, including enrichment of cell-bound albumin and up-regulation of endoplasmic reticulum (ER- and mitochondrial-specific chaperones to protect mitochondrial integrity, which were not observed in other necrotic cells, including HUH-7, A2780, A549 and HOC1a. Our results show that the cell-bound albumin originates in the culture medium rather than from monocyte-derived hepatocytes, and that HSP60 is a potential binding partner of the cell-bound albumin. Proteomic analysis shows that HSP60 and protein disulfide isomerase are the most abundant up-regulated mitochondrial and ER-chaperones, and that both HSP60 and calreticulin are ubiquitinated in necrotic monocytes. In contrast, expression levels of the cytosolic chaperones HSP90 and HSP71 were down-regulated in the azacytidine-treated monocytes, concomitant with an increase in the levels of these chaperones in the cell culture medium. Collectively, our results demonstrates that chaperones from different organelles behave differently in necrotic monocytes, ER- and mitochondrial chaperones being retained and cytosolic and nuclear chaperones being released into the cell culture medium through the ruptured cell membrane. HSP60 may serve as a new target for development of myeloid leukemia treatment.

  3. Nickel sulfate induced apoptosis via activating ROS-dependent mitochondria and endoplasmic reticulum stress pathways in rat Leydig cells.

    Science.gov (United States)

    Zou, Lingyue; Su, Li; Sun, Yifan; Han, Aijie; Chang, Xuhong; Zhu, An; Liu, Fangfang; Li, Jin; Sun, Yingbiao

    2017-07-01

    Nickel can induce apoptosis of testicular Leydig cells in mice, whereas the mechanisms remain unclear. In this study, we investigated the role of nickel-induced reactive oxygen species (ROS) generation in mitochondria and endoplasmic reticulum stress (ERS) mediated apoptosis pathways in rat Leydig cells. Fluorescent DCF and Annexin-V FITC/PI staining were performed to measure the production of ROS and apoptosis in Leydig cells. RT-qPCR and Western blot were conducted to analyze the key genes and proteins involved in mitochondria and ERS apoptotic pathways. The results showed that nickel sulfate induced ROS generation, consequently resulted in nucleolus deformation and apoptosis in testicular Leydig cells, which were then attenuated by ROS inhibitors of N-acetylcysteine (NAC) and 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO). Nickel sulfate-triggered Leydig cells apoptosis via mitochondria and ERS pathways was characterized by the upregulated mRNA and proteins expression of Bak, cytochrome c, caspase 9, caspase 3, GRP78, GADD153, and caspase 12, which were inhibited by NAC and TEMPO respectively. The findings indicated that nickel-induced ROS generation was involved in apoptosis via mitochondria and ERS pathways in rat Leydig cells. © 2017 Wiley Periodicals, Inc.

  4. Activating transcription factor 4 is involved in endoplasmic reticulum stress-mediated apoptosis contributing to vascular calcification.

    Science.gov (United States)

    Duan, Xiao-Hui; Chang, Jin-Rui; Zhang, Jing; Zhang, Bao-Hong; Li, Yu-Lin; Teng, Xu; Zhu, Yi; Du, Jie; Tang, Chao-Shu; Qi, Yong-Fen

    2013-09-01

    Our previous work reported that endoplasmic reticulum stress (ERS)-mediated apoptosis was activated during vascular calcification (VC). Activating transcription factor 4 (ATF4) is a critical transcription factor in osteoblastogenesis and ERS-induced apoptosis. However, whether ATF4 is involved in ERS-mediated apoptosis contributing to VC remains unclear. In the present study, in vivo VC was induced in rats by administering vitamin D3 plus nicotine. Vascular smooth muscle cell (VSMC) calcification in vitro was induced by incubation in calcifying media containing β-glycerophosphate and CaCl2. ERS inhibitors taurine or 4-phenylbutyric acid attenuated ERS and VSMC apoptosis in calcified rat arteries, reduced calcification and retarded the VSMC contractile phenotype transforming into an osteoblast-like phenotype in vivo. Inhibition of ERS retarded the VSMC phenotypic transition into an osteoblast-like cell phenotype and reduced VSMC calcification and apoptosis in vitro. Interestingly, ATF4 was activated in calcified aortas and calcified VSMCs in vitro. ATF4 knockdown attenuated ERS-induced apoptosis in calcified VSMCs. ATF4 deficiency blocked VSMC calcification and negatively regulated the osteoblast phenotypic transition of VSMCs in vitro. Our results demonstrate that ATF4 was involved at least in part in the process of ERS-mediated apoptosis contributing to VC.

  5. Inhibition of Calcium Influx Reduces Dysfunction and Apoptosis in Lipotoxic Pancreatic β-Cells via Regulation of Endoplasmic Reticulum Stress.

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    Yuren Zhou

    Full Text Available Lipotoxicity plays an important role in pancreatic β-cell failure during the development of type 2 diabetes. Prolonged exposure of β-cells to elevated free fatty acids level could cause deterioration of β-cell function and induce cell apoptosis. Therefore, inhibition of fatty acids-induced β-cell dysfunction and apoptosis might provide benefit for the therapy of type 2 diabetes. The present study examined whether regulation of fatty acids-triggered calcium influx could protect pancreatic β-cells from lipotoxicity. Two small molecule compounds, L-type calcium channel blocker nifedipine and potassium channel activator diazoxide were used to inhibit palmitic acid-induced calcium influx. And whether the compounds could reduce palmitic acid-induced β-cell failure and the underlying mechanism were also investigated. It was found that both nifedipine and diazoxide protected MIN6 pancreatic β-cells and primary cultured murine islets from palmitic acid-induced apoptosis. Meanwhile, the impaired insulin secretion was also recovered to varying degrees by these two compounds. Our results verified that nifedipine and diazoxide could reduce palmitic acid-induced endoplasmic reticulum stress to generate protective effects on pancreatic β-cells. More importantly, it suggested that regulation of calcium influx by small molecule compounds might provide benefits for the prevention and therapy of type 2 diabetes.

  6. Monascuspiloin enhances the radiation sensitivity of human prostate cancer cells by stimulating endoplasmic reticulum stress and inducing autophagy.

    Directory of Open Access Journals (Sweden)

    Hui-Wen Chiu

    Full Text Available Prostate cancer is a very common cancer among males. Traditional treatments for prostate cancer have limited efficacy; therefore, new therapeutic strategies and/or new adjuvant drugs must be explored. Red yeast rice (RYR is a traditional food spice made in Asia by fermenting white rice with Monascus purpureus Went yeast. Accumulating evidence indicates that RYR has antitumor activity. In this study, PC-3 cells (human prostate cancer cells were used to investigate the anti-cancer effects of ionizing radiation (IR combined with monascuspiloin (MP, a yellow pigment isolated from Monascus pilosus M93-fermented rice and to determine the underlying mechanisms of these effects in vitro and in vivo. We found that IR combined with MP showed increased therapeutic efficacy when compared with either treatment alone in PC-3 cells. In addition, the combined treatment enhanced DNA damage and endoplasmic reticulum (ER stress. The combined treatment induced primarily autophagy in PC-3 cells, and the cell death that was induced by the combined treatment was chiefly the result of inhibition of the Akt/mTOR signaling pathways. In an in vivo study, the combination treatment showed greater anti-tumor growth effects. These novel findings suggest that the combined treatment could be a potential therapeutic strategy for prostate cancer.

  7. Dieldrin-induced neurotoxicity involves impaired mitochondrial bioenergetics and an endoplasmic reticulum stress response in rat dopaminergic cells.

    Science.gov (United States)

    Schmidt, Jordan T; Rushin, Anna; Boyda, Jonna; Souders, Christopher Laurence; Martyniuk, Christopher J

    2017-08-24

    Mitochondria are sensitive targets of environmental chemicals. Dieldrin (DLD) is an organochlorine pesticide that remains a human health concern due to high lipid bioaccumulation, and it has been epidemiologically associated to an increased risk for Parkinson's disease (PD). As mitochondrial dysfunction is involved in the etiology of PD, this study aimed to determine whether DLD impaired mitochondrial bioenergetics in dopaminergic cells. Rat immortalized dopaminergic N27 cells were treated for 24 or 48h with one dose of either a solvent control, 2.5, 25, or 250μM DLD. Dopaminergic cells treated with 250μM DLD showed increased Casp3/7 activity at 24 and 48h. DLD also caused a dose dependent reduction in cell viability of ∼25-30% over 24h. No significant effects on cell viability, apoptosis, nor cytotoxicity were detected at 24 or 48h with 2.5μM DLD. Following a 24h exposure to 2.5 and 25μM DLD, viable cells were subjected to a mitochondrial stress test using the Seahorse XFe24 Extracellular Flux Analyzer. Following three independent experiments conducted for rigor, dopaminergic cells that were treated with 2.5 and 25μM DLD consistently showed a reduction in maximum respiration and spare capacity compared to the control group. Molecular responses were measured to determine mechanisms of DLD-induced mitochondrial dysfunction. There were no changes in transcripts associated with mitochondrial membrane potential and permeability (e.g. Ant, Hk1, Tspo, Vdac), nor PI3 K/Akt/mTor signaling or mitochondrial-associated apoptotic factors (Bax, Bcl2, Casp3). However, transcript levels for Chop/Gadd153 (DNA Damage Inducible Transcript 3), an apoptotic gene activated following endoplasmic reticulum (ER) stress, were 3-fold higher in N27 cells treated with DLD, suggesting that DLD-induced mitochondrial dysfunction is related to ER stress. Dopamine cells were also assessed for changes in tyrosine hydroxylase (TH) protein, which did not differ among treatments. This study

  8. Methamphetamine induces dopamine D1 receptor-dependent endoplasmic reticulum stress-related molecular events in the rat striatum.

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    Subramaniam Jayanthi

    Full Text Available Methamphetamine (METH is an illicit toxic psychostimulant which is widely abused. Its toxic effects depend on the release of excessive levels of dopamine (DA that activates striatal DA receptors. Inhibition of DA-mediated neurotransmission by the DA D1 receptor antagonist, SCH23390, protects against METH-induced neuronal apoptosis. The initial purpose of the present study was to investigate, using microarray analyses, the influence of SCH23390 on transcriptional responses in the rat striatum caused by a single METH injection at 2 and 4 hours after drug administration. We identified 545 out of a total of 22,227 genes as METH-responsive. These include genes which are involved in apoptotic pathways, endoplasmic reticulum (ER stress, and in transcription regulation, among others. Of these, a total of 172 genes showed SCH23390-induced inhibition of METH-mediated changes. Among these SCH23390-responsive genes were several genes that are regulated during ER stress, namely ATF3, HSP27, Hmox1, HSP40, and CHOP/Gadd153. The secondary goal of the study was to investigate the role of DA D1 receptor stimulation on the expression of genes that participate in ER stress-mediated molecular events. We thus used quantitative PCR to confirm changes in the METH-responsive ER genes identified by the microarray analyses. We also measured the expression of these genes and of ATF4, ATF6, BiP/GRP78, and of GADD34 over a more extended time course. SCH23390 attenuated or blocked METH-induced increases in the expression of the majority of these genes. Western blot analysis revealed METH-induced increases in the expression of the antioxidant protein, Hmox1, which lasted for about 24 hours after the METH injection. Additionally, METH caused DA D1 receptor-dependent transit of the Hmox1 regulator protein, Nrf2, from cytosolic into nuclear fractions where the protein exerts its regulatory functions. When taken together, these findings indicate that SCH23390 can provide

  9. AAV exploits subcellular stress associated with inflammation, endoplasmic reticulum expansion, and misfolded proteins in models of cystic fibrosis.

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    Jarrod S Johnson

    2011-05-01

    Full Text Available Barriers to infection act at multiple levels to prevent viruses, bacteria, and parasites from commandeering host cells for their own purposes. An intriguing hypothesis is that if a cell experiences stress, such as that elicited by inflammation, endoplasmic reticulum (ER expansion, or misfolded proteins, then subcellular barriers will be less effective at preventing viral infection. Here we have used models of cystic fibrosis (CF to test whether subcellular stress increases susceptibility to adeno-associated virus (AAV infection. In human airway epithelium cultured at an air/liquid interface, physiological conditions of subcellular stress and ER expansion were mimicked using supernatant from mucopurulent material derived from CF lungs. Using this inflammatory stimulus to recapitulate stress found in diseased airways, we demonstrated that AAV infection was significantly enhanced. Since over 90% of CF cases are associated with a misfolded variant of Cystic Fibrosis Transmembrane Conductance Regulator (ΔF508-CFTR, we then explored whether the presence of misfolded proteins could independently increase susceptibility to AAV infection. In these models, AAV was an order of magnitude more efficient at transducing cells expressing ΔF508-CFTR than in cells expressing wild-type CFTR. Rescue of misfolded ΔF508-CFTR under low temperature conditions restored viral transduction efficiency to that demonstrated in controls, suggesting effects related to protein misfolding were responsible for increasing susceptibility to infection. By testing other CFTR mutants, G551D, D572N, and 1410X, we have shown this phenomenon is common to other misfolded proteins and not related to loss of CFTR activity. The presence of misfolded proteins did not affect cell surface attachment of virus or influence expression levels from promoter transgene cassettes in plasmid transfection studies, indicating exploitation occurs at the level of virion trafficking or processing. Thus

  10. Cigarette smoke induces endoplasmic reticulum stress and the unfolded protein response in normal and malignant human lung cells

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    Yang Jin

    2008-08-01

    Full Text Available Abstract Background Although lung cancer is among the few malignancies for which we know the primary etiological agent (i.e., cigarette smoke, a precise understanding of the temporal sequence of events that drive tumor progression remains elusive. In addition to finding that cigarette smoke (CS impacts the functioning of key pathways with significant roles in redox homeostasis, xenobiotic detoxification, cell cycle control, and endoplasmic reticulum (ER functioning, our data highlighted a defensive role for the unfolded protein response (UPR program. The UPR promotes cell survival by reducing the accumulation of aberrantly folded proteins through translation arrest, production of chaperone proteins, and increased degradation. Importance of the UPR in maintaining tissue health is evidenced by the fact that a chronic increase in defective protein structures plays a pathogenic role in diabetes, cardiovascular disease, Alzheimer's and Parkinson's syndromes, and cancer. Methods Gene and protein expression changes in CS exposed human cell cultures were monitored by high-density microarrays and Western blot analysis. Tissue arrays containing samples from 110 lung cancers were probed with antibodies to proteins of interest using immunohistochemistry. Results We show that: 1 CS induces ER stress and activates components of the UPR; 2 reactive species in CS that promote oxidative stress are primarily responsible for UPR activation; 3 CS exposure results in increased expression of several genes with significant roles in attenuating oxidative stress; and 4 several major UPR regulators are increased either in expression (i.e., BiP and eIF2α or phosphorylation (i.e., phospho-eIF2α in a majority of human lung cancers. Conclusion These data indicate that chronic ER stress and recruitment of one or more UPR effector arms upon exposure to CS may play a pivotal role in the etiology or progression of lung cancers, and that phospho-eIF2α and BiP may have

  11. Olmesartan, an AT1 Antagonist, Attenuates Oxidative Stress, Endoplasmic Reticulum Stress and Cardiac Inflammatory Mediators in Rats with Heart Failure Induced by Experimental Autoimmune Myocarditis

    Science.gov (United States)

    Sukumaran, Vijayakumar; Watanabe, Kenichi; Veeraveedu, Punniyakoti T.; Gurusamy, Narasimman; Ma, Meilei; Thandavarayan, Rajarajan A.; Lakshmanan, Arun Prasath; Yamaguchi, Ken'ichi; Suzuki, Kenji; Kodama, Makoto

    2011-01-01

    Studies have demonstrated that angiotensin II has been involved in immune and inflammatory responses which might contribute to the pathogenesis of immune-mediated diseases. Recent evidence suggests that oxidative stress may play a role in myocarditis. Here, we investigated whether olmesartan, an AT1R antagonist protects against experimental autoimmune myocarditis (EAM) by suppression of oxidative stress, endoplasmic reticulum (ER) stress and inflammatory cytokines. EAM was induced in Lewis rats by immunization with porcine cardiac myosin, were divided into two groups and treated with either olmesartan (10 mg/kg/day) or vehicle for a period of 21 days. Myocardial functional parameters measured by hemodynamic and echocardiographic analyses were significantly improved by the treatment with olmesartan compared with those of vehicle-treated rats. Treatment with olmesartan attenuated the myocardial mRNA expressions of proinflammatory cytokines, [Interleukin (IL)-1β, monocyte chemoattractant protein-1, tumor necrosis factor-α and interferon-γ)] and the protein expression of tumor necrosis factor-α compared with that of vehicle-treated rats. Myocardial protein expressions of AT1R, NADPH oxidase subunits (p47phox, p67phox, gp91phox) and the expression of markers of oxidative stress (3-nitrotyrosine and 4-hydroxy-2-nonenal), and the cardiac apoptosis were also significantly decreased by the treatment with olmesartan compared with those of vehicle-treated rats. Furthermore, olmesartan treatment down-regulated the myocardial expressions of glucose regulated protein-78, growth arrest and DNA damage-inducible gene, caspase-12, phospho-p38 mitogen-activated protein kinase (MAPK) and phospho-JNK. These findings suggest that olmesartan protects against EAM in rats, at least in part via suppression of oxidative stress, ER stress and inflammatory cytokines. PMID:21383952

  12. Nutrient deprivation induces α-synuclein aggregation through endoplasmic reticulum stress response and SREBP2 pathway

    OpenAIRE

    Jiang, Peizhou; Gan, Ming; Lin, Wen-Lang; Yen, Shu-Hui C.

    2014-01-01

    Abnormal accumulation of filamentous α-synuclein (α-syn) in neurons, regarded as Lewy bodies (LBs), are a hallmark of Parkinson disease (PD). Although the exact mechanism(s) underlying LBs formation remains unknown, autophagy and ER stress response have emerged as two important pathways affecting α-syn aggregation. In present study we tested whether cells with the tetracycline-off inducible overexpression of α-syn and accumulating α-syn aggregates can benefit from autophagy activation elicite...

  13. Nutrient deprivation induces α-synuclein aggregation through endoplasmic reticulum stress response and SREBP2 pathway

    OpenAIRE

    Peizhou eJiang; Ming eGan; Wen-Lang eLin; Yen, Shu-Hui C.

    2014-01-01

    Abnormal accumulation of filamentous α-synuclein (α-syn) in neurons, regarded as Lewy bodies(LBs), are a hallmark of Parkinson disease (PD). Although the exact mechanism(s) underlying LBs formation remains unknown, autophagy and ER stress response have emerged as two important pathways affecting α-syn aggregation. In present study we tested whether cells with the tetracycline-off inducible overexpression of α-syn and accumulating α-syn aggregates can benefit from autophagy activation elicited...

  14. Involvement of endoplasmic reticulum stress in albuminuria induced inflammasome activation in renal proximal tubular cells.

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    Li Fang

    Full Text Available Albuminuria contributes to the progression of tubulointerstitial fibrosis. Although it has been demonstrated that ongoing albuminuria leads to tubular injury manifested by the overexpression of numerous proinflammatory cytokines, the mechanism remains largely unknown. In this study, we found that the inflammasome activation which has been recognized as one of the cornerstones of intracellular surveillance system was associated with the severity of albuminuria in the renal biopsies specimens. In vitro, bovine serum albumin (BSA could also induce the activation of NLRP3 inflammasome in the cultured kidney epithelial cells (NRK-52E. Since there was a significant overlap of NLRP3 with the ER marker calreticulin, the ER stress provoked by BSA seemed to play a crucial role in the activation of inflammasome. Here, we demonstrated that the chemical chaperone taurine-conjugated ursodeoxycholic acid (TUDCA which was proved to be an enhancer for the adaptive capacity of ER could attenuate the inflammasome activation induced by albuminuria not only in vitro but also in diabetic nephropathy. Taken together, these data suggested that ER stress seemed to play an important role in albuminuria-induced inflammasome activation, elimination of ER stress via TUDCA might hold promise as a novel avenue for preventing inflammasome activation ameliorating kidney epithelial cells injury induced by albuminuria.

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

    Science.gov (United States)

    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.

  16. FBXO6-Mediated Ubiquitination and Degradation of Ero1L Inhibits Endoplasmic Reticulum Stress-Induced Apoptosis

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    Xi Chen

    2016-11-01

    Full Text Available Background/Aims: FBXO6 is the substrate recognition component of a Skp1-Cullin1-F-box protein (SCF ubiquitin E3 ligase complex, recognizing the chitobiose in unfolded N-glycoprotein to target glycoproteins for polyubiquitination and degradation. Although how FBXO6 recognizes glycoprotein has been fully investigated, the ubiquitination substrates of FBXO6 remain largely unknown. Previously, we have systematically identified the glycoproteins that interact with FBXO6 in an N-glycan dependent manner by LC/MS spectrum and confirmed the interaction between FBXO6 and glycosylated Ero1L, a protein disulfide oxidase in endoplasmic reticulum (ER. Methods: The relationship between endogenous Ero1L and exogenous Flag-FBXO6 were determined by Western blot. In vivo ubiquitination assay was used to detect the direct effect of FBXO6 in the regulation of Ero1L. Both CCK8 and FACS assays were used to determine the apoptosis ratio of cells after treatments. Results: Ero1L is a ubiquitination substrate of FBXO6. FBXO6 mediates the degradation of Ero1L through a ubiquitylation-dependent pathway. Overexpression of FBXO6 increased the polyubiquitination and decreased the stability of Ero1L, whereas inhibition of FBXO6 prolonged the half-life of Ero1L. Functionally, we show that FBXO6 inhibits ER stress-induced apoptosis by modulating the protein level of Ero1L. Conclusion: Collectively, our results demonstrate FBXO6 as a functional E3 ubiquitin ligase for Ero1L that plays a critical role in inhibiting ER stress-induced apoptosis.

  17. Kaempferol induces apoptosis in HepG2 cells via activation of the endoplasmic reticulum stress pathway.

    Science.gov (United States)

    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.

  18. Surfactant protein A2 mutations associated with pulmonary fibrosis lead to protein instability and endoplasmic reticulum stress.

    Science.gov (United States)

    Maitra, Meenakshi; Wang, Yongyu; Gerard, Robert D; Mendelson, Carole R; Garcia, Christine Kim

    2010-07-16

    Rare heterozygous mutations in the gene encoding surfactant protein A2 (SP-A2, SFTPA2) are associated with adult-onset pulmonary fibrosis and adenocarcinoma of the lung. We have previously shown that two recombinant SP-A2 mutant proteins (G231V and F198S) remain within the endoplasmic reticulum (ER) of A549 cells and are not secreted into the culture medium. The pathogenic mechanism of the mutant proteins is unknown. Here we analyze all common and rare variants of the surfactant protein A2, SP-A2, in both A549 cells and in primary type II alveolar epithelial cells. We show that, in contrast with all other SP-A2 variants, the mutant proteins are not secreted into the medium with wild-type SP-A isoforms, form fewer intracellular dimer and trimer oligomers, are partially insoluble in 0.5% Nonidet P-40 lysates of transfected A549 cells, and demonstrate greater protein instability in chymotrypsin proteolytic digestions. Both the G231V and F198S mutant SP-A2 proteins are destroyed via the ER-association degradation pathway. Expression of the mutant proteins increases the transcription of a BiP-reporter construct, expression of BiP protein, and production of an ER stress-induced XBP-1 spliced product. Human bronchoalveolar wash samples from individuals who are heterozygous for the G231V mutation have similar levels of total SP-A as normal family members, which suggests that the mechanism of disease does not involve an overt lack of secreted SP-A but instead involves an increase in ER stress of resident type II alveolar epithelial cells.

  19. Hydrogen sulfide protects against endoplasmic reticulum stress and mitochondrial injury in nucleus pulposus cells and ameliorates intervertebral disc degeneration.

    Science.gov (United States)

    Xu, Daoliang; Jin, Haiming; Wen, Jianxia; Chen, Jiaoxiang; Chen, Deheng; Cai, Ningyu; Wang, Yongli; Wang, Jianle; Chen, Yu; Zhang, Xiaolei; Wang, Xiangyang

    2017-03-01

    It has been suggested that excessive apoptosis in intervertebral disc cells induced by inflammatory cytokines, such as interleukin (IL)-1β, is related to the process of intervertebral disc degeneration (IVDD). Hydrogen sulfide (H2S), a gaseous signaling molecule, has drawn attention for its anti-apoptosis role in various pathophysiological processes in degenerative diseases. To date, there has been no investigation of the correlation of H2S production and IVDD or of the effects of H2S on IL-1β-induced apoptosis in nucleus pulposus (NP) cells. Here, we found that the expression levels of cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE), two key enzymes in the generation of H2S, were significantly decreased in human degenerate NP tissues as well as in IL-1β-treated NP cells. NaHS (H2S donor) administration showed a protective effect by inhibiting the endoplasmic reticulum (ER) stress response and mitochondrial dysfunction induced by IL-1β stimulation in vitro, the effect was related to activation of the PI3K/Akt and ERK1/2 signaling pathways. Suppression of these pathways by specific inhibitors, LY294002 and PD98059, partially reduced the protective effect of NaHS. Moreover, in the percutaneous needle puncture disc degeneration rat tail model, disc degeneration was partially reversed by NaHS administration. Taken together, our results suggest that H2S plays a protective role in IVDD and the underlying mechanism involves PI3K/Akt and ERK1/2 signaling pathways-mediated suppression of ER stress and mitochondrial dysfunction in IL-1β-induced NP cells.

  20. The endoplasmic reticulum stress response is associated with insulin resistance-mediated drug resistance in HepG2 cells.

    Science.gov (United States)

    Li, L; Li, G; Wei, H; Sun, J; Chen, J; Xie, B; Wang, B; Gu, J; Li, C; Tian, B; Wang, F

    2015-01-01

    Insulin resistance has a close relationship with tumorigenesis, tumor progression, and cancer prognosis. Importantly, the liver is the main target tissue of insulin, and the resistance to chemotherapeutic agents has been reported in hepatocarcinoma. However, little is known about the relationship between drug resistance and insulin resistance in hepatocarcinoma. Therefore, we treated HepG2 cells (a human hepatoma cell line) with high concentrations of insulin to establish a cell-based model of insulin resistance (HepG2/IR cells) to define the relationship between insulin resistance and the resistance to chemotherapy. We identified that HepG2/IR cells exhibited stable insulin resistance, with decreased glucose consumption, reduced glycogen synthesis, and decreased expression of the insulin receptor gene. HepG2/IR cells also exhibited endoplasmic reticulum (ER) dilatation and degranulation. Molecular markers of endoplasmic reticulum stress, including glucose-regulated protein78 (GRP78) and phosphorylated protein kinase R-like ER kinase (p-PERK), increased significantly, which was accompanied by increased reactive oxygen metabolism and decreased mitochondrial membrane potential. In addition, HepG2/IR cells were resistant to the chemotherapy agent Adriamycin, which was accompanied by the upregulation of multidrug resistance gene 1/ P-glycoprotein (P-gp; an endoplasmic reticulum chaperone that plays a role in ER stress), and enhanced drug efflux. These data suggest that the endoplasmic reticulum (ER) stress response was active in HepG2/IR cells, and that insulin resistance was related to drug resistance in HepG2 cells. Interestingly, the ER stress and chemotherapy resistance observed in HepG2/IR cells could be reversed by treatment with the insulin sensitizer pioglitazone. Therefore, our study suggests that there is a close relationship between the resistance to chemotherapy and insulin resistance in HepG2 cells, and that the ER stress response play a role in insulin

  1. Modeling perceived stress via HRV and accelerometer sensor streams.

    Science.gov (United States)

    Wu, Min; Cao, Hong; Nguyen, Hai-Long; Surmacz, Karl; Hargrove, Caroline

    2015-08-01

    Discovering and modeling of stress patterns of human beings is a key step towards achieving automatic stress monitoring, stress management and healthy lifestyle. As various wearable sensors become popular, it becomes possible for individuals to acquire their own relevant sensory data and to automatically assess their stress level on the go. Previous studies for stress analysis were conducted in the controlled laboratory and clinic settings. These studies are not suitable for stress monitoring in one's daily life as various physical activities may affect the physiological signals. In this paper, we address such issue by integrating two modalities of sensors, i.e., HRV sensors and accelerometers, to monitor the perceived stress levels in daily life. We gathered both the heart and the motion data from 8 participants continuously for about 2 weeks. We then extracted features from both sensory data and compared the existing machine learning methods for learning personalized models to interpret the perceived stress levels. Experimental results showed that Bagging classifier with feature selection is able to achieve a prediction accuracy 85.7%, indicating our stress monitoring on daily basis is fairly practical.

  2. Waste disposal in the endoplasmic reticulum, ROS production and plant salt stress response

    Institute of Scientific and Technical Information of China (English)

    Aldo Ceriotti

    2011-01-01

    @@ Even under normal conditions, both newly synthesized polypeptides and polypeptides that have already achieved a native conformation can misfold and thus be exposed to the risk of aggregation.Misfolded proteins can be toxic to cells, since they may be prone to spurious interactions or be endowed with undesirable biological activities.The list of possible causes that may lead to the production of a misfolded protein is rather long but includes genetic mutations, error in transcription and translation, and cellular alterations, such asheat shock or oxidative stress.

  3. Ulinastatin suppresses endoplasmic reticulum stress and apoptosis in the hippocampus of rats with acute paraquat poisoning

    Directory of Open Access Journals (Sweden)

    Hai-feng Li

    2015-01-01

    Full Text Available Lung injury is the main manifestation of paraquat poisoning. Few studies have addressed brain damage after paraquat poisoning. Ulinastatin is a protease inhibitor that can effectively stabilize lysosomal membranes, prevent cell damage, and reduce the production of free radicals. This study assumed that ulinastatin would exert these effects on brain tissues that had been poisoned with paraquat. Rat models of paraquat poisoning were intraperitoneally injected with ulinastatin. Simultaneously, rats in the control group were administered normal saline. Hematoxylin-eosin staining showed that most hippocampal cells were contracted and nucleoli had disappeared in the paraquat group. Fewer cells in the hippocampus were concentrated and nucleoli had disappeared in the ulinastatin group. Western blot assay showed that expressions of GRP78 and cleaved-caspase-3 were significantly lower in the ulinastatin group than in the paraquat group. Immunohistochemical findings showed that CHOP immunoreactivity was significantly lower in the ulinastatin group than in the paraquat group. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining showed that the number of apoptotic cells was reduced in the paraquat and ulinastatin groups. These data confirmed that endoplasmic reticular stress can be induced by acute paraquat poisoning. Ulinastatin can effectively inhibit this stress as well as cell apoptosis, thereby exerting a neuroprotective effect.

  4. Ulinastatin suppresses endoplasmic reticulum stress and apoptosis in the hippocampus of rats with acute paraquat poisoning

    Institute of Scientific and Technical Information of China (English)

    Hai-feng Li; Shi-xing Zhao; Bao-peng Xing; Ming-li Sun

    2015-01-01

    Lung injury is the main manifestation of paraquat poisoning. Few studies have addressed brain damage after paraquat poisoning. Ulinastatin is a protease inhibitor that can effectively stabilize lysosomal membranes, prevent cell damage, and reduce the production of free radicals. This study assumed that ulinastatin would exert these effects on brain tissues that had been poisoned with paraquat. Rat models of paraquat poisoning were intraperitoneally injected with ulinastatin. Simultaneously, rats in the control group were administered normal saline. Hematoxylin-eosin staining showed that most hippocampal cells were contracted and nucleoli had disappeared in the paraquat group. Fewer cells in the hippocampus were concentrated and nucleoli had dis-appeared in the ulinastatin group. Western blot assay showed that expressions of GRP78 and cleaved-caspase-3 were signiifcantly lower in the ulinastatin group than in the paraquat group. Immunohistochemical ifndings showed that CHOP immunoreactivity was signiifcantly lower in the ulinastatin group than in the paraquat group. Terminal deoxynucleotidyl transferase-medi-ated dUTP nick end labeling staining showed that the number of apoptotic cells was reduced in the paraquat and ulinastatin groups. These data conifrmed that endoplasmic reticular stress can be induced by acute paraquat poisoning. Ulinastatin can effectively inhibit this stress as well as cell apoptosis, thereby exerting a neuroprotective effect.

  5. Pharmacological inhibition of cystine-glutamate exchange induces endoplasmic reticulum stress and ferroptosis.

    Science.gov (United States)

    Dixon, Scott J; Patel, Darpan N; Welsch, Matthew; Skouta, Rachid; Lee, Eric D; Hayano, Miki; Thomas, Ajit G; Gleason, Caroline E; Tatonetti, Nicholas P; Slusher, Barbara S; Stockwell, Brent R

    2014-05-20

    Exchange of extracellular cystine for intracellular glutamate by the antiporter system xc (-) is implicated in numerous pathologies. Pharmacological agents that inhibit system xc (-) activity with high potency have long been sought, but have remained elusive. In this study, we report that the small molecule erastin is a potent, selective inhibitor of system xc (-). RNA sequencing revealed that inhibition of cystine-glutamate exchange leads to activation of an ER stress response and upregulation of CHAC1, providing a pharmacodynamic marker for system xc (-) inhibition. We also found that the clinically approved anti-cancer drug sorafenib, but not other kinase inhibitors, inhibits system xc (-) function and can trigger ER stress and ferroptosis. In an analysis of hospital records and adverse event reports, we found that patients treated with sorafenib exhibited unique metabolic and phenotypic alterations compared to patients treated with other kinase-inhibiting drugs. Finally, using a genetic approach, we identified new genes dramatically upregulated in cells resistant to ferroptosis.DOI: http://dx.doi.org/10.7554/eLife.02523.001.

  6. Oxidative stress mediated Ca(2+) release manifests endoplasmic reticulum stress leading to unfolded protein response in UV-B irradiated human skin cells.

    Science.gov (United States)

    Farrukh, Mufti R; Nissar, Ul A; Afnan, Quadri; Rafiq, Rather A; Sharma, Love; Amin, Shajrul; Kaiser, Peerzada; Sharma, Parduman R; Tasduq, Sheikh A

    2014-07-01

    Exposure of skin to ultraviolet (UV) radiation, an environmental stressor induces number of adverse biological effects (photodamage), including cancer. The damage induced by UV-irradiation in skin cells is initiated by the photochemical generation of reactive oxygen species (ROS) and induction of endoplasmic reticulum (ER) stress and consequent activation of unfolded protein response (UPR). To decipher cellular and molecular events responsible for UV-B mediated ER stress and UPR activation in skin cells. The study was performed on human skin fibroblast (Hs68) and keratinocyte (HaCaT) cells exposed to UV-B radiations in lab conditions. Different parameters of UVB induced cellular and molecular changes were analyzed using Western-blotting, microscopic studies and flow cytometry. Our results depicted that UV-B induces an immediate ROS generation that resulted in emptying of ER Ca(2+) stores inducing ER stress and activation of PERK-peIF2α-CHOP pathway. Quenching ROS generation by anti-oxidants prevented Ca(2+) release and subsequent induction of ER stress and UPR activation. UV-B irradiation induced PERK dependent G2/M phase cell cycle arrest in Hs68 and G1/S phase cell cycle arrest in HaCaT. Also our study reflects that UV-B exposure leads to loss of mitochondrial membrane potential, activation of apoptotic cascade as evident by AnnexinV/PI staining, decreased expression of Bcl-2 and increased cleavage of PARP-1 protein. UV-B induced Ca(2+) deficit within ER lumen was mediated by immediate ROS generation. Insufficient Ca(2+) concentration within ER lumen developed ER stress leading to UPR activation. These changes were reversed by use of anti-oxidants which quench ROS. Copyright © 2014 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

  7. Shear stress induces human aortic endothelial cell apoptosis via interleukin‑1 receptor‑associated kinase 2‑induced endoplasmic reticulum stress.

    Science.gov (United States)

    Pan, Longfei; Hong, Zhou; Yu, Lei; Gao, Yanxia; Zhang, Rui; Feng, Hui; Su, Lijuan; Wang, Gang

    2017-09-19

    Atherosclerosis is characterized by localized lesions distributed in the arterial tree due to the shear stress produced by blood flow. Endothelial cells are directly affected by alterations in blood flow. Dysfunction and injury to endothelial cells has been hypothesized to initiate the pathological processes of atherosclerosis. The present study aimed to investigate the mechanism of shear stress‑induced endothelial cellular apoptosis. Shear stress was generated using an artificial device to mimic the impact of disturbed blood flow on cultured human aortic endothelial cells (HAECs). Cellular apoptosis was assessed using a terminal deoxynucleotidyl transferase dUTP nick end labeling assay; an ELISA assay was used to detect the produced interleukin (IL)‑1β; specific small interfering (si)RNA was used to knockdown the expression of interleukin‑1 receptor‑associated kinase 2 (IRAK2) in HAECs and the expression levels of 78 kDa glucose‑regulated protein, DNA damage‑inducible transcript 3 protein (CHOP), IRAK2 and IL‑1β were evaluated using western blotting. The results of the present study demonstrated that artificial shear stress induced endoplasmic reticulum (ER) stress, IL‑1β production and apoptosis in HAECs in a time‑dependent manner. The inhibition of ER stress, and treatment with interleukin‑1 receptor antagonist protein and siRNA against IRAK2 attenuated shear stress‑induced CHOP signaling‑mediated cellular apoptosis. Therefore, overproduction of IL‑1β exacerbated shear stress‑induced ER stress‑mediated apoptosis via the IRAK2/CHOP signaling pathway in endothelial cells.

  8. Silica nanoparticles induce endoplasmic reticulum stress response, oxidative stress and activate the mitogen-activated protein kinase (MAPK signaling pathway

    Directory of Open Access Journals (Sweden)

    Verena Christen

    2014-01-01

    Full Text Available Application of silica nanoparticles (SiO2-NPs may result in human exposure. Here we investigate unexplored modes of action by which SiO2-NPs with average size of 225 nm act on human hepatoma cells (Huh7. We focused on the endoplasmic (ER stress response and on mitogen-activated protein kinase (MAPK signaling pathways. Both pathways were induced. ER stress and the associated three unfolded protein response (UPR pathways were activated as demonstrated by significant inductions of BiP and XBP-1s and a moderate but significant induction of ATF-4 at 0.05 and 0.5 mg/ml. In addition to activation of NFкB interferon stimulated genes IP-10, IRF-9, and ISG-15 were up-regulated. As a consequence of ER stress, the pro-inflammatory cytokine TNFα and PP2Ac were induced following exposure to 0.05 mg/ml SiO2-NPs. Additionally, this occurred at 0.005 mg/ml SiO2-NPs for TNFα at 24 h. This in turn led to a strong transcriptional induction of MAP-kinases and its target genes cJun, cMyc and CREB. A strong transcriptional down-regulation of the proapoptotic gene p53 occurred at 0.05 and 0.5 mg/ml SiO2-NP. Exposure of Huh7 cells to the anti-oxidant N-acetyl cysteine reduced transcriptional induction of ER stress markers demonstrating a link between the induction of oxidative stress and ER stress. Our study demonstrates that SiO2-NPs lead to strong ER stress and UPR induction, oxidative stress, activation of MAPK signaling and down-regulation of p53. All of these activated pathways, which are analyzed here for the first time in detail, inhibit apoptosis and induce cell proliferation, which may contribute to a hepatotoxic, inflammatory and tumorigenic action of SiO2-NPs.

  9. Endoplasmic Reticulum Stress Induced Synthesis of a Novel Viral Factor Mediates Efficient Replication of Genotype-1 Hepatitis E Virus.

    Directory of Open Access Journals (Sweden)

    Vidya P Nair

    2016-04-01

    Full Text Available Hepatitis E virus (HEV causes acute hepatitis in many parts of the world including Asia, Africa and Latin America. Though self-limiting in normal individuals, it results in ~30% mortality in infected pregnant women. It has also been reported to cause acute and chronic hepatitis in organ transplant patients. Of the seven viral genotypes, genotype-1 virus infects humans and is a major public health concern in South Asian countries. Sporadic cases of genotype-3 and 4 infection in human and animals such as pigs, deer, mongeese have been reported primarily from industrialized countries. Genotype-5, 6 and 7 viruses are known to infect animals such as wild boar and camel, respectively. Genotype-3 and 4 viruses have been successfully propagated in the laboratory in mammalian cell culture. However, genotype-1 virus replicates poorly in mammalian cell culture and no other efficient model exists to study its life cycle. Here, we report that endoplasmic reticulum (ER stress promotes genotype-1 HEV replication by inducing cap-independent, internal initiation mediated translation of a novel viral protein (named ORF4. Importantly, ORF4 expression and stimulatory effect of ER stress inducers on viral replication is specific to genotype-1. ORF4 protein sequence is mostly conserved among genotype-1 HEV isolates and ORF4 specific antibodies were detected in genotype-1 HEV patient serum. ORF4 interacted with multiple viral and host proteins and assembled a protein complex consisting of viral helicase, RNA dependent RNA polymerase (RdRp, X, host eEF1α1 (eukaryotic elongation factor 1 isoform-1 and tubulinβ. In association with eEF1α1, ORF4 stimulated viral RdRp activity. Furthermore, human hepatoma cells that stably express ORF4 or engineered proteasome resistant ORF4 mutant genome permitted enhanced viral replication. These findings reveal a positive role of ER stress in promoting genotype-1 HEV replication and pave the way towards development of an efficient

  10. The Impact of Intermittent and Repetitive Cold Stress Exposure on Endoplasmic Reticulum Stress and Instability of Atherosclerotic Plaques

    Directory of Open Access Journals (Sweden)

    Ming-Xiang Dai

    2014-07-01

    Full Text Available Background: The incidence of acute coronary syndrome caused by the rupture of atherosclerotic plaque and subsequent arterial thrombosis increases as the weather gets colder. However, the association between cold stress and atherosclerotic plaque rupture is currently unknown. Methods: An atherosclerotic plaque model was established in rabbits by balloon injury and a high-fat diet with or without cold stress (4°C, 1 hour per day, 20 weeks at the onset of modeling. Additionally, oxidized low-density lipoprotein (ox-LDL was applied to induce the formation of macrophage foam cells in vitro. Results: Serum lipid profiles and inflammatory cytokines (ox-LDL, high-sensitivity C-reactive protein, and interleukin-8 were significantly higher in cold stress-exposed rabbits than in controls (PConclusions: Cold stress may enhance the instability of atherosclerotic plaques through activating ERS and enhancing cell apoptosis. Up-regulated CHOP levels mediated by PERK and ATF6 and the activated IRE1-XBP1-JNK pathway contributed to the apoptosis of foam cells.

  11. Ethanol metabolism, oxidative stress, and endoplasmic reticulum stress responses in the lungs of hepatic alcohol dehydrogenase deficient deer mice after chronic ethanol feeding

    Energy Technology Data Exchange (ETDEWEB)

    Kaphalia, Lata [Department of Internal Medicine, The University of Texas Medical Branch, Galveston, TX 775555 (United States); Boroumand, Nahal [Department of Pathology, The University of Texas Medical Branch, Galveston, TX 775555 (United States); Hyunsu, Ju [Department of Preventive Medicine and Community Health, The University of Texas Medical Branch, Galveston, TX 775555 (United States); Kaphalia, Bhupendra S., E-mail: bkaphali@utmb.edu [Department of Pathology, The University of Texas Medical Branch, Galveston, TX 775555 (United States); Calhoun, William J. [Department of Internal Medicine, The University of Texas Medical Branch, Galveston, TX 775555 (United States)

    2014-06-01

    Consumption and over-consumption of alcoholic beverages are well-recognized contributors to a variety of pulmonary disorders, even in the absence of intoxication. The mechanisms by which alcohol (ethanol) may produce disease include oxidative stress and prolonged endoplasmic reticulum (ER) stress. Many aspects of these processes remain incompletely understood due to a lack of a suitable animal model. Chronic alcohol over-consumption reduces hepatic alcohol dehydrogenase (ADH), the principal canonical metabolic pathway of ethanol oxidation. We therefore modeled this situation using hepatic ADH-deficient deer mice fed 3.5% ethanol daily for 3 months. Blood ethanol concentration was 180 mg% in ethanol fed mice, compared to < 1.0% in the controls. Acetaldehyde (oxidative metabolite of ethanol) was minimally, but significantly increased in ethanol-fed vs. pair-fed control mice. Total fatty acid ethyl esters (FAEEs, nonoxidative metabolites of ethanol) were 47.6 μg/g in the lungs of ethanol-fed mice as compared to 1.5 μg/g in pair-fed controls. Histological and immunohistological evaluation showed perivascular and peribronchiolar lymphocytic infiltration, and significant oxidative injury, in the lungs of ethanol-fed mice compared to pair-fed controls. Several fold increases for cytochrome P450 2E1, caspase 8 and caspase 3 found in the lungs of ethanol-fed mice as compared to pair-fed controls suggest role of oxidative stress in ethanol-induced lung injury. ER stress and unfolded protein response signaling were also significantly increased in the lungs of ethanol-fed mice. Surprisingly, no significant activation of inositol-requiring enzyme-1α and spliced XBP1 was observed indicating a lack of activation of corrective mechanisms to reinstate ER homeostasis. The data suggest that oxidative stress and prolonged ER stress, coupled with formation and accumulation of cytotoxic FAEEs may contribute to the pathogenesis of alcoholic lung disease. - Highlights: • Chronic

  12. GmNAC30 and GmNAC81 integrate the endoplasmic reticulum stress- and osmotic stress-induced cell death responses through a vacuolar processing enzyme.

    Science.gov (United States)

    Mendes, Giselle C; Reis, Pedro A B; Calil, Iara P; Carvalho, Humberto H; Aragão, Francisco J L; Fontes, Elizabeth P B

    2013-11-26

    Prolonged endoplasmic reticulum and osmotic stress synergistically activate the stress-induced N-rich protein-mediated signaling that transduces a cell death signal by inducing GmNAC81 (GmNAC6) in soybean. To identify novel regulators of the stress-induced programmed cell death (PCD) response, we screened a two-hybrid library for partners of GmNAC81. We discovered another member of the NAC (NAM-ATAF1,2-CUC2) family, GmNAC30, which binds to GmNAC81 in the nucleus of plant cells to coordinately regulate common target promoters that harbor the core cis-regulatory element TGTG[TGC]. We found that GmNAC81 and GmNAC30 can function either as transcriptional repressors or activators and cooperate to enhance the transcriptional regulation of common target promoters, suggesting that heterodimerization may be required for the full regulation of gene expression. Accordingly, GmNAC81 and GmNAC30 display overlapping expression profiles in response to multiple environmental and developmental stimuli. Consistent with a role in PCD, GmNAC81 and GmNAC30 bind in vivo to and transactivate hydrolytic enzyme promoters in soybean protoplasts. A GmNAC81/GmNAC30 binding site is located in the promoter of the caspase-1-like vacuolar processing enzyme (VPE) gene, which is involved in PCD in plants. We demonstrated that the expression of GmNAC81 and GmNAC30 fully transactivates the VPE gene in soybean protoplasts and that this transactivation was associated with an increase in caspase-1-like activity. Collectively, our results indicate that the stress-induced GmNAC30 cooperates with GmNAC81 to activate PCD through the induction of the cell death executioner VPE.

  13. Quercetin induces endoplasmic reticulum stress to enhance cDDP cytotoxicity in ovarian cancer: involvement of STAT3 signaling.

    Science.gov (United States)

    Yang, Zongyuan; Liu, Yi; Liao, Jing; Gong, Cheng; Sun, Chaoyang; Zhou, Xiaoshui; Wei, Xiao; Zhang, Taoran; Gao, Qinglei; Ma, Ding; Chen, Gang

    2015-03-01

    There is an urgent need to make cisplatin (cDDP) more effective and less toxic in the treatment of ovarian cancer for its systemic side effects and high resistance rate. In this study, we investigated the effect of quercetin (Qu) pretreatment on the potentiation of cDDP in ovarian cancer. We found that Qu pretreatment significantly enhanced cDDP cytotoxicity in an ovarian cancer cell line and primary cancer cells. In addition, we demonstrated that Qu elicited obvious endoplasmic reticulum stress (ERS) and activated all three branches of ERS in ovarian cancer. Specific inhibitors of each ERS pathway, as well as the general ERS stabilizer tauroursodeoxycholic acid, notably diminished such enhancing effects. Furthermore, Qu notably suppressed STAT3 phosphorylation, leading to downregulation of the BCL-2 gene downstream of STAT3. Moreover, blocking ERS restored the protein levels of phosphorylated STAT3 as well as BCL-2 expression, thus abolishing the chemosensitization potency of Qu; these results revealed that Qu affected the STAT3 pathway to enhance cDDP cytotoxicity, and this effect involved ERS signaling. In a xenograft mouse model of ovarian cancer, Qu enhanced the antitumor effect of cDDP. Tumors from mice treated with cDDP in combination with Qu pretreatment had repressed STAT3 phosphorylation, lower BCL-2 and higher apoptosis levels compared with those from the other groups. Meanwhile, Qu markedly reduced the elevation of blood creatinine during cDDP intervention. These data indicate that Qu pretreatment potentiates the antitumor effects of cDDP in ovarian cancer while protecting the kidneys against damage. Therefore the strategy of Qu pretreatment may be beneficial in enhancing the therapeutic efficacy of cDDP against ovarian cancer. © 2015 FEBS.

  14. The protective effect of lycopene on hypoxia/reoxygenation-induced endoplasmic reticulum stress in H9C2 cardiomyocytes.

    Science.gov (United States)

    Gao, Yang; Jia, Pengyu; Shu, WenQi; Jia, Dalin

    2016-03-05

    Nowadays, drugs protecting ischemia/reperfusion (I/R) myocardium become more suitable for clinic. It has been confirmed lycopene has various protections, but lacking the observation of its effect on endoplasmic reticulum stress (ERS)-mediated apoptosis caused by hypoxia/reoxygenation (H/R). This study aims to clarify the protective effect of lycopene on ERS induced by H/R in H9C2 cardiomyocytes. Detect the survival rate, lactic dehydrogenase (LDH) activity, apoptosis ratio, glucose-regulated proteins 78 (GRP78), C/EBP homologous protein (CHOP), c-Jun-N-terminal protein Kinase (JNK) and Caspase-12 mRNA and protein expression and phosphorylation of JNK (p-JNK) protein expression. LDH activity, apoptosis ratio and GRP78 protein expression increase in the H/R group, reduced by lycopene. The survival rate reduces in the H/R and thapsigargin (TG) groups; lycopene and 4-phenyl butyric acid (4-PBA) can improve it caused by H/R, lycopene also can improve it caused by TG. The apoptosis ratio, the expression of GRP78, CHOP and Caspase-12 mRNA and protein and p-JNK protein increase in the H/R and TG groups, weaken in the lycopene+H/R, 4-PBA+H/R and lycopene+TG groups. There is no obvious change in the expression of JNK mRNA or protein. Hence, our results provide the evidence that 10 μM lycopene plays an obviously protective effect on H/R H9C2 cardiomyocytes, realized through reducing ERS and apoptosis. The possible mechanism may be related to CHOP, p-JNK and Caspase-12 pathways.

  15. The expression of Lamin A mutant R321X leads to endoplasmic reticulum stress with aberrant Ca(2+) handling.

    Science.gov (United States)

    Carmosino, Monica; Gerbino, Andrea; Schena, Giorgia; Procino, Giuseppe; Miglionico, Rocchina; Forleo, Cinzia; Favale, Stefano; Svelto, Maria

    2016-11-01

    Mutations in the Lamin A/C gene (LMNA), which encodes A-type nuclear Lamins, represent the most frequent genetic cause of dilated cardiomyopathy (DCM). This study is focused on a LMNA nonsense mutation (R321X) identified in several members of an Italian family that produces a truncated protein isoform, which co-segregates with a severe form of cardiomyopathy with poor prognosis. However, no molecular mechanisms other than nonsense mediated decay of the messenger and possible haploinsufficiency were proposed to explain DCM. Aim of this study was to gain more insights into the disease-causing mechanisms induced by the expression of R321X at cellular level. We detected the expression of R321X by Western blotting from whole lysate of a mutation carrier heart biopsy. When expressed in HEK293 cells, GFP- (or mCherry)-tagged R321X mislocalized in the endoplasmic reticulum (ER) inducing the PERK-CHOP axis of the ER stress response. Of note, confocal microscopy showed phosphorylation of PERK in sections of the mutation carrier heart biopsy. ER mislocalization of mCherry-R321X also induced impaired ER Ca(2+) handling, reduced capacitative Ca(2+) entry at the plasma membrane and abnormal nuclear Ca(2+) dynamics. In addition, expression of R321X by itself increased the apoptosis rate. In conclusion, R321X is the first LMNA mutant identified to date, which mislocalizes into the ER affecting cellular homeostasis mechanisms not strictly related to nuclear functions. © 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  16. Global mass spectrometry and transcriptomics array based drug profiling provides novel insight into glucosamine induced endoplasmic reticulum stress.

    Science.gov (United States)

    Carvalho, Ana Sofia; Ribeiro, Helena; Voabil, Paula; Penque, Deborah; Jensen, Ole N; Molina, Henrik; Matthiesen, Rune

    2014-12-01

    We investigated the molecular effects of glucosamine supplements, a popular and safe alternative to nonsteroidal anti-inflammatory drugs, for decreasing pain, inflammation, and maintaining healthy joints. Numerous studies have reported an array of molecular effects after glucosamine treatment. We questioned whether the differences in the effects observed in previous studies were associated with the focus on a specific subproteome or with the use of specific cell lines or tissues. To address this question, global mass spectrometry- and transcription array-based glucosamine drug profiling was performed on malignant cell lines from different stages of lymphocyte development. We combined global label-free MS-based protein quantitation with an open search for modifications to obtain the best possible proteome coverage. Our data were largely consistent with previous studies in a variety of cellular models. We mainly observed glucosamine induced O-GlcNAcylation/O-GalNAcylation (O-HexNAcylation); however, we also observed global and local changes in acetylation, methylation, and phosphorylation. For example, our data provides two additional examples of "yin-yang" between phosphorylation and O-HexNAcylation. Furthermore, we mapped novel O-HexNAc sites on GLU2B and calnexin. GLU2B and calnexin are known to be located in the endoplasmic reticulum (ER) and involved in protein folding and quality control. The O-HexNAc sites were regulated by glucosamine treatment and correlated with the up-regulation of the ER stress marker GRP78. The occupancy of O-HexNAc on GLU2B and calnexin sites differed between the cytosolic and nuclear fractions with a higher occupancy in the cytosolic fraction. Based on our data we propose the hypothesis that O-HexNAc either inactivates calnexin and/or targets it to the cytosolic fraction. Further, we hypothesize that O-HexNAcylation induced by glucosamine treatment enhances protein trafficking.

  17. The invasion of tobacco mosaic virus RNA induces endoplasmic reticulum stress-related autophagy in HeLa cells.

    Science.gov (United States)

    Li, Li; Wang, Li; Xiao, Ruijing; Zhu, Guoguo; Li, Yan; Liu, Changxuan; Yang, Ru; Tang, Zhiqing; Li, Jie; Huang, Wei; Chen, Lang; Zheng, Xiaoling; He, Yuling; Tan, Jinquan

    2012-04-01

    The ability of human cells to defend against viruses originating from distant species has long been ignored. Owing to the pressure of natural evolution and human exploration, some of these viruses may be able to invade human beings. If their 'fresh' host had no defences, the viruses could cause a serious pandemic, as seen with HIV, SARS (severe acute respiratory syndrome) and avian influenza virus that originated from chimpanzees, the common palm civet and birds, respectively. It is unknown whether the human immune system could tolerate invasion with a plant virus. To model such an alien virus invasion, we chose TMV (tobacco mosaic virus) and used human epithelial carcinoma cells (HeLa cells) as its 'fresh' host. We established a reliable system for transfecting TMV-RNA into HeLa cells and found that TMV-RNA triggered autophagy in HeLa cells as shown by the appearance of autophagic vacuoles, the conversion of LC3-I (light chain protein 3-I) to LC3-II, the up-regulated expression of Beclin1 and the accumulation of TMV protein on autophagosomal membranes. We observed suspected TMV virions in HeLa cells by TEM (transmission electron microscopy). Furthermore, we found that TMV-RNA was translated into CP (coat protein) in the ER (endoplasmic reticulum) and that TMV-positive RNA translocated from the cytoplasm to the nucleolus. Finally, we detected greatly increased expression of GRP78 (78 kDa glucose-regulated protein), a typical marker of ERS (ER stress) and found that the formation of autophagosomes was closely related to the expanded ER membrane. Taken together, our data indicate that HeLa cells used ERS and ERS-related autophagy to defend against TMV-RNA.

  18. Gadolinium chloride elicits apoptosis in human osteosarcoma U-2 OS cells through extrinsic signaling, intrinsic pathway and endoplasmic reticulum stress.

    Science.gov (United States)

    Tsai, Yuh-Feng; Huang, Ching-Wen; Chiang, Jo-Hua; Tsai, Fuu-Jen; Hsu, Yuan-Man; Lu, Chi-Cheng; Hsiao, Chen-Yu; Yang, Jai-Sing

    2016-12-01

    Gadolinium (Gd) compounds are important as magnetic resonance imaging (MRI) contrast agents, and are potential anticancer agents. However, no report has shown the effect of gadolinium chloride (GdCl3) on osteosarcoma in vitro. The present study investigated the apoptotic mechanism of GdCl3 on human osteosarcoma U-2 OS cells. Our results indicated that GdCl3 significantly reduced cell viability of U-2 OS cells in a concentration-dependent manner. GdCl3 led to apoptotic cell shrinkage and DNA fragmentation in U-2 OS cells as revealed by morphologic changes and TUNEL staining. Colorimetric assay analyses also showed that activities of caspase-3, caspase-8, caspase-9 and caspase-4 occurred in GdCl3-treated U-2 OS cells. Pretreatment of cells with pan-caspase inhibitor (Z-VAD-FMK) and specific inhibitors of caspase-3/-8/-9 significantly reduced cell death caused by GdCl3. The increase of cytoplasmic Ca2+ level, ROS production and the decrease of mitochondria membrane potential (ΔΨm) were observed by flow cytometric analysis in U-2 OS cells after GdCl3 exposure. Western blot analyses demonstrated that the levels of Fas, FasL, cytochrome c, Apaf-1, GADD153 and GRP78 were upregulated in GdCl3-treated U-2 OS cells. In conclusion, death receptor, mitochondria-dependent and endoplasmic reticulum (ER) stress pathways contribute to GdCl3-induced apoptosis in U-2 OS cells. GdCl3 might have potential to be used in treatment of osteosarcoma patients.

  19. Mechanism of ghrelin in improving cardiac function by inhibiting endoplasmic reticulum stress in rats with acute myocardial infarctio

    Directory of Open Access Journals (Sweden)

    Min CAI

    2012-11-01

    Full Text Available Objective  To establish the rat model of acute myocardial infarction (AMI, and to explore the mechanism of ghrelin in improving cardiac function through inhibiting endoplasmic reticulum stress (ERS. Methods  AMI model was reproduced in 18 adult male Sprague-Dawley rats (220±20g by ligation of the left anterior descending coronary artery. Four days after the reproduction of the model, 14 survived rats with AMI were randomly divided into two groups (7 each: model group, animals were subcutaneously (sc injected with normal saline only; treatment group, animals were given ghrelin (100μg/kg twice a day (12h interval for two weeks. In addition, a sham-operated group was set up (Sham operation+saline, n=8. Two weeks later, the cardiac function was examined by echocardiography (UCG, the morphological changes in myocardial tissue were observed with hematoxylin-eosin (HE staining, the levels of LDH and CK-MB were determined by ELISA, and the expressions of glucose-regulated protein 78 (GRP-78 and C/EBP homologous protein (CHOP were assessed by Western blotting. Results  AMI model was successfully reproduced in SD rats. Compared with the rats in sham group, those in model group showed poor cardiac function (P < 0.05, HE staining revealed loosening of tissue and edema, ELISA revealed elevation of serum LDH and CK-MB levels (P < 0.05, and up regulation of expressions of GRP-78 and CHOP protein (P < 0.05. While compared with model group, rats in treatment group showed better cardiac function (P < 0.05, tissue loosening and edema were alleviated, the levels of serum LDH and CK-MB lowered (P < 0.05, and inhibition of the expressions of GRP-78 and CHOP protein (P < 0.05. Conclusion  Ghrelin may improve the cardiac function by in hibiting ERS, thus ameliorating the myocardial damage caused by AMI.

  20. Dithiothreitol enhanced arsenic-trioxide-induced cell apoptosis in cultured oral cancer cells via mitochondrial dysfunction and endoplasmic reticulum stress.

    Science.gov (United States)

    Tsai, Chia-Wen; Yang, Mei-Due; Hsia, Te-Chun; Chang, Wen-Shin; Hsu, Chin-Mu; Hsieh, Yi-Hsien; Chung, Jing-Gung; Bau, Da-Tian

    2017-01-01

    Arsenic is naturally occurring toxic metalloid and drinking As2 O3 containing water are recognized to be related to increased risk of neurotoxicity, liver injury, blackfoot disease, hypertension, and cancer. On the contrary, As2 O3 has been an ancient drug used in traditional Chinese medicine with substantial anticancer activities, especially in the treatment of acute promyelocytic leukemia as well as chronic wound healing. However, the cytotoxicity and detail mechanisms of As2 O3 action in solid cancer cells, such as oral cancer cells, are largely unknown. In this study, we have primarily cultured four pairs of tumor and nontumor cells from the oral cancer patients and treated the cells with As2 O3 alone or combined with dithiothreitol (DTT). The results showed that 0.5 μM As2 O3 plus 20 μM DTT caused a significant cell death of oral cancer cells but not the nontumor cells. Also As2 O3 plus DTT upregulated Bax and Bak, downregulated Bcl-2 and p53, caused a loss of mitochondria membrane potential in oral cancer cells. On the other way, As2 O3 also triggered endoplasmic reticulum stress and increased the levels of glucose-regulated protein 78, calpain 1 and 2. Our results suggest that DTT could synergistically enhance the effects of As2 O3 on killing oral cancer cells while nontoxic to the nontumor cells. The combination is promising for clinical practice in oral cancer therapy and worth further investigations. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 17-27, 2017.

  1. The invasion of tobacco mosaic virus RNA induces endoplasmic reticulum stress-related autophagy in HeLa cells

    Science.gov (United States)

    Li, Li; Wang, Li; Xiao, Ruijing; Zhu, Guoguo; Li, Yan; Liu, Changxuan; Yang, Ru; Tang, Zhiqing; Li, Jie; Huang, Wei; Chen, Lang; Zheng, Xiaoling; He, Yuling; Tan, Jinquan

    2011-01-01

    The ability of human cells to defend against viruses originating from distant species has long been ignored. Owing to the pressure of natural evolution and human exploration, some of these viruses may be able to invade human beings. If their ‘fresh’ host had no defences, the viruses could cause a serious pandemic, as seen with HIV, SARS (severe acute respiratory syndrome) and avian influenza virus that originated from chimpanzees, the common palm civet and birds, respectively. It is unknown whether the human immune system could tolerate invasion with a plant virus. To model such an alien virus invasion, we chose TMV (tobacco mosaic virus) and used human epithelial carcinoma cells (HeLa cells) as its ‘fresh’ host. We established a reliable system for transfecting TMV-RNA into HeLa cells and found that TMV-RNA triggered autophagy in HeLa cells as shown by the appearance of autophagic vacuoles, the conversion of LC3-I (light chain protein 3-I) to LC3-II, the up-regulated expression of Beclin1 and the accumulation of TMV protein on autophagosomal membranes. We observed suspected TMV virions in HeLa cells by TEM (transmission electron microscopy). Furthermore, we found that TMV-RNA was translated into CP (coat protein) in the ER (endoplasmic reticulum) and that TMV-positive RNA translocated from the cytoplasm to the nucleolus. Finally, we detected greatly increased expression of GRP78 (78 kDa glucose-regulated protein), a typical marker of ERS (ER stress) and found that the formation of autophagosomes was closely related to the expanded ER membrane. Taken together, our data indicate that HeLa cells used ERS and ERS-related autophagy to defend against TMV-RNA. PMID:21729006

  2. Aluminium induced endoplasmic reticulum stress mediated cell death in SH-SY5Y neuroblastoma cell line is independent of p53.

    Science.gov (United States)

    Mustafa Rizvi, Syed Husain; Parveen, Arshiya; Verma, Anoop K; Ahmad, Iqbal; Arshad, Md; Mahdi, Abbas Ali

    2014-01-01

    Aluminium (Al) is the third most abundant element in the earth's crust and its compounds are used in the form of house hold utensils, medicines and in antiperspirant etc. Increasing number of evidences suggest the involvement of Al+3 ions in a variety of neurodegenerative disorders including Alzheimer's disease. Here, we have attempted to investigate the role of Al in endoplasmic reticulum stress and the regulation of p53 during neuronal apoptosis using neuroblastoma cell line. We observed that Al caused oxidative stress by increasing ROS production and intracellular calcium levels together with depletion of intracellular GSH levels. We also studied modulation of key pro- and anti-apoptotic proteins and found significant alterations in the levels of Nrf2, NQO1, pAKT, p21, Bax, Bcl2, Aβ1-40 and Cyt c together with increase in endoplasmic reticulum (ER) stress related proteins like CHOP and caspase 12. However, with respect to the role of p53, we observed downregulation of its transcript as well as protein levels while analysis of its ubiquitination status revealed no significant changes. Not only did Al increase the activities of caspase 9, caspase 12 and caspase 3, but, by the use of peptide inhibitors of specific and pan-caspases, we observed significant protection against neuronal cell death upon inhibition of caspase 12, demonstrating the prominent role of endoplasmic reticulum stress generated responses in Al toxicity. Overall our findings suggest that Al induces ER stress and ROS generation which compromises the antioxidant defenses of neuronal cells thereby promoting neuronal apoptosis in p53 independent pathway.

  3. Mitochondrial reticulum network dynamics in relation to oxidative stress, redox regulation, and hypoxia.

    Science.gov (United States)

    Jezek, Petr; Plecitá-Hlavatá, Lydie

    2009-10-01

    A single mitochondrial network in the cell undergoes constant fission and fusion primarily depending on the local GTP gradients and the mitochondrial energetics. Here we overview the main properties and regulation of pro-fusion and pro-fission mitodynamins, i.e. dynamins-related GTPases responsible for mitochondrial shape-forming, such as pro-fusion mitofusins MFN1, MFN2, and the inner membrane-residing long OPA1 isoforms, and pro-fission mitodynamins FIS1, MFF, and DRP1 multimers required for scission. Notably, the OPA1 cleavage into non-functional short isoforms at a diminished ATP level (collapsed membrane potential) and the DRP1 recruitment upon phosphorylation by various kinases are overviewed. Possible responses of mitodynamins to the oxidative stress, hypoxia, and concomitant mtDNA mutations are also discussed. We hypothesize that the increased GTP formation within the Krebs cycle followed by the GTP export via the ADP/ATP carrier shift the balance between fission and fusion towards fusion by activating the GTPase domain of OPA1 located in the peripheral intermembrane space (PIMS). Since the protein milieu of PIMS is kept at the prevailing oxidized redox potential by the TOM, MIA40 and ALR/Erv1 import-redox trapping system, redox regulations shift the protein environment of PIMS to a more reduced state due to the higher substrate load and increased respiration. A higher cytochrome c turnover rate may prevent electron transfer from ALR/Erv1 to cytochrome c. Nevertheless, the putative links between the mitodynamin responses, mitochondrial morphology and the changes in the mitochondrial bioenergetics, superoxide production, and hypoxia are yet to be elucidated, including the precise basis for signaling by the mitochondrion-derived vesicles.

  4. Fructose supplementation impairs rat liver autophagy through mTORC activation without inducing endoplasmic reticulum stress.

    Science.gov (United States)

    Baena, Miguel; Sangüesa, Gemma; Hutter, Natalia; Sánchez, Rosa M; Roglans, Núria; Laguna, Juan C; Alegret, Marta

    2015-02-01

    Supplementation with 10% liquid fructose to female rats for 2weeks caused hepatic steatosis through increased lipogenesis and reduced peroxisome proliferator activated receptor (PPAR) α activity and fatty acid catabolism, together with increased expression of the spliced form of X-binding protein-1 (Rebollo et al., 2014). In the present study, we show that some of these effects are preserved after sub-chronic (8weeks) fructose supplementation, specifically increased hepatic expression of lipid synthesis-related genes (stearoyl-CoA desaturase, ×6.7-fold; acetyl-CoA carboxylase, ×1.6-fold; glycerol-3-phosphate acyltransferase, ×1.65-fold), and reduced fatty acid β-oxidation (×0.77-fold), resulting in increased liver triglyceride content (×1.69-fold) and hepatic steatosis. However, hepatic expression of PPARα and its target genes was not modified and, further, livers of 8-week fructose-supplemented rats showed no sign of unfolded protein response activation, except for an increase in p-IRE1 levels. Hepatic mTOR phosphorylation was enhanced (×1.74-fold), causing an increase in the phosphorylation of UNC-51-like kinase 1 (ULK-1) (×2.8-fold), leading to a decrease in the ratio of LC3B-II/LC3B-I protein expression (×0.39-fold) and an increase in the amount of the autophagic substrate p62, indicative of decreased autophagy activity. A harmful cycle may be established in the liver of 8-week fructose-supplemented rats where lipid accumulation may cause defective autophagy, and reduced autophagy may result in decreased free fatty acid formation from triglyceride depots, thus reducing the substrates for β-oxidation and further increasing hepatic steatosis. In summary, the length of supplementation is a key factor in the metabolic disturbances induced by fructose: in short-term studies, PPARα inhibition and ER stress induction are critical events, whereas after sub-chronic supplementation, mTOR activation and autophagy inhibition are crucial.

  5. Monitoring Pre-Stressed Composites Using Optical Fibre Sensors

    Directory of Open Access Journals (Sweden)

    Sriram Krishnamurthy

    2016-05-01

    Full Text Available Residual stresses in fibre reinforced composites can give rise to a number of undesired effects such as loss of dimensional stability and premature fracture. Hence, there is significant merit in developing processing techniques to mitigate the development of residual stresses. However, tracking and quantifying the development of these fabrication-induced stresses in real-time using conventional non-destructive techniques is not straightforward. This article reports on the design and evaluation of a technique for manufacturing pre-stressed composite panels from unidirectional E-glass/epoxy prepregs. Here, the magnitude of the applied pre-stress was monitored using an integrated load-cell. The pre-stressing rig was based on a flat-bed design which enabled autoclave-based processing. A method was developed to end-tab the laminated prepregs prior to pre-stressing. The development of process-induced residual strain was monitored in-situ using embedded optical fibre sensors. Surface-mounted electrical resistance strain gauges were used to measure the strain when the composite was unloaded from the pre-stressing rig at room temperature. Four pre-stress levels were applied prior to processing the laminated preforms in an autoclave. The results showed that the application of a pre-stress of 108 MPa to a unidirectional [0]16 E-glass/913 epoxy preform, reduced the residual strain in the composite from −600 µε (conventional processing without pre-stress to approximately zero. A good correlation was observed between the data obtained from the surface-mounted electrical resistance strain gauge and the embedded optical fibre sensors. In addition to “neutralising” the residual stresses, superior axial orientation of the reinforcement can be obtained from pre-stressed composites. A subsequent publication will highlight the consequences of pres-stressing on fibre alignment, the tensile, flexural, compressive and fatigue performance of unidirectional E

  6. Experimental Development of a Novel Stress Sensor for in situ Stress Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Polsky, Yarom [ORNL; Lance, Michael J [ORNL; Mattus, Catherine H [ORNL; Daniels, Ryan J [ORNL

    2016-01-01

    This paper will describe ongoing work to adapt a previously demonstrated method for measuring stress in ceramics to develop a borehole deployed in situ stress sensor. The method involves the use of a cementitious material which exhibits a strong piezo-spectroscopic stress response as a downhole stress gage. A description of the conceptual approach will be provided along with preliminary analysis and proof-of-concept laboratory results.

  7. CHIP, a carboxy terminus HSP-70 interacting protein, prevents cell death induced by endoplasmic reticulum stress in the central nervous system.

    Science.gov (United States)

    Cabral Miranda, Felipe; Adão-Novaes, Juliana; Hauswirth, William W; Linden, Rafael; Petrs-Silva, Hilda; Chiarini, Luciana B

    2014-01-01

    Endoplasmic reticulum (ER) stress and protein misfolding are associated with various neurodegenerative diseases. ER stress activates unfolded protein response (UPR), an adaptative response. However, severe ER stress can induce cell death. Here we show that the E3 ubiquitin ligase and co-chaperone Carboxyl Terminus HSP70/90 Interacting Protein (CHIP) prevents neuron death in the hippocampus induced by severe ER stress. Organotypic hippocampal slice cultures (OHSCs) were exposed to Tunicamycin, a pharmacological ER stress inducer, to trigger cell death. Overexpression of CHIP was achieved with a recombinant adeno-associated viral vector (rAAV) and significantly diminished ER stress-induced cell death, as shown by analysis of propidium iodide (PI) uptake, condensed chromatin, TUNEL and cleaved caspase 3 in the CA1 region of OHSCs. In addition, overexpression of CHIP prevented upregulation of both CHOP and p53 both pro-apoptotic pathways induced by ER stress. We also detected an attenuation of eIF2a phosphorylation promoted by ER stress. However, CHIP did not prevent upregulation of BiP/GRP78 induced by UPR. These data indicate that overexpression of CHIP attenuates ER-stress death response while maintain ER stress adaptative response in the central nervous system. These results indicate a neuroprotective role for CHIP upon UPR signaling. CHIP emerge as a candidate for clinical intervention in neurodegenerative diseases associated with ER stress.

  8. Adiponectin protects rat myocardium against chronic intermittent hypoxia-induced injury via inhibition of endoplasmic reticulum stress.

    Directory of Open Access Journals (Sweden)

    Wenxiao Ding

    Full Text Available Obstructive sleep apnea syndrome (OSAS is associated with many cardiovascular disorders such as heart failure, hypertension, atherosclerosis, and arrhythmia and so on. Of the many associated factors, chronic intermittent hypoxia (CIH in particular is the primary player in OSAS. To assess the effects of CIH on cardiac function secondary to OSAS, we established a model to study the effects of CIH on Wistar rats. Specifically, we examined the possible underlying cellular mechanisms of hypoxic tissue damage and the possible protective role of adiponectin against hypoxic insults. In the first treatment group, rats were exposed to CIH conditions (nadir O2, 5-6% for 8 hours/day, for 5 weeks. Subsequent CIH-induced cardiac dysfunction was measured by echocardiograph. Compared with the normal control (NC group, rats in the CIH-exposed group experienced elevated levels of left ventricular end-systolic dimension and left ventricular end-systolic volume and depressed levels of left ventricular ejection fraction and left ventricular fractional shortening (p<0.05. However, when adiponectin (Ad was added in CIH + Ad group, we saw a rescue in the elevations of the aforementioned left ventricular function (p<0.05. To assess critical cardiac injury, we detected myocardial apoptosis by Terminal deoxynucleotidyl transfer-mediated dUTP nick end-labeling (TUNEL analysis. It was showed that the apoptosis percentage in CIH group (2.948% was significantly higher than that in NC group (0.4167% and CIH + Ad group (1.219% (p<0.05. Protein expressions of cleaved caspase-3, cleaved caspase-9, and cleaved-caspase-12 validated our TUNEL results (p<0.05. Mechanistically, our results demonstrated that the proteins expressed with endoplasmic reticulum stress and the expression of reactive oxygen species (ROS were significantly elevated under CIH conditions, whereas Ad supplementation partially decreased them. Overall, our results suggested that Ad augmentation could improve CIH

  9. Ameliorated stress related proteins are associated with improved cardiac function by sarcoplasmic reticulum calcium ATPase gene transfer in heart failure

    Institute of Scientific and Technical Information of China (English)

    Zhi-Qing Fu; Xiao-Ying Li; Xiao-Chun Lu; Ya-Fei Mi; Tao Liu; Wei-Hua Ye

    2012-01-01

    Background Previous studies showed that overexpression of sarco-endoplasmic reticulum calcium ATPase (SERCA2a) in a variety of heart failure (HF) models was associated with greatly enhanced cardiac performance. However, it still undefined the effect of SERCA2a overexpression on the systemic inflammatory response and neuro-hormonal factors. Methods A rapid right ventricular pacing model of experimental HF was used in beagles. Then the animals underwent recombinant adeno-associated virus 1 (rAAV1) mediated gene transfection by direct intra-myocardium injection. HF animals were randomized to receive the SERCA2a gene, enhanced green fluorescent protein (control) gene, or equivalent phosphate buffered saline. Thirty days after gene delivery, the cardiac function was evaluated by echocardiographic testing. The protein level of SERCA2a was measured by western blotting. The proteomic analysis of left ventricular (LV) sample was determined using two-dimensional (2-D) gel electrophoresis and MALDI-TOF-MS. The serum levels of the systemic inflammatory and neuro-hormonal factors were assayed using radioimmunoassay kits. Results The cardiac function improved after SERCA- 2a gene transfer due to the significantly increased SERCA2a protein level. Beagles treated with SERCA2a had significantly decreased serum levels of the inflammatory markers (interleukin-6 and tumor necrosis factor-α) and neuro-hormonal factors (brain natriuretic peptide, endothelin-1 and angiotensin Ⅱ) compared with HF animals. The myocardial proteomic analysis showed that haptoglobin heavy chain, heat shock protein (alpha-crystallin-related, B6) were down-regulated, and galectin-1 was up-regulated in SERCA2a group compared with HF group, companied by up-regulated contractile proteins and NADH dehydrogenase. Conclusions These findings demonstrate that regional intramyocardial injections of rAAV1-SERCA2a vectors may improve global LV function, correlating with reverse activation of the systemic inflammatory

  10. Surface micromachined differential piezoelectric shear-stress sensors

    Science.gov (United States)

    Williams, Randall P.; Kim, Donghwan; Gawalt, David P.; Hall, Neal A.

    2017-01-01

    The ability to measure viscous wall shear stress in high-speed flows is important for verifying simulated results typically obtained from direct numerical simulation in the aerodynamics research community, and robust sensors are required to measure wall shear reliably under such high-speed conditions. This letter summarizes the design, fabrication, and testing of a surface micromachined piezoelectric shear-stress sensor which uses a thin piezoelectric film to generate a voltage proportional to an applied shear stress without additional moving parts. A differential-cell architecture is used to enhance selectivity to shear stress while canceling normal-stress sensitivity. The conceptual design, fabrication details, and experimental measurements of device sensitivity are presented. A finite element model is used to validate the device performance against measurements, and to provide insight into the potential and electric fields underlying the device concept. The potential for understanding device behavior and optimization through modeling is illustrated using finite element analysis results. The minimum detectable shear stress for the sensor is estimated to be 52.9 mPa  √Hz-1 at 1.5 kHz.

  11. Fisetin induces apoptosis and endoplasmic reticulum stress in human non-small cell lung cancer through inhibition of the MAPK signaling pathway.

    Science.gov (United States)

    Kang, Kyoung Ah; Piao, Mei Jing; Madduma Hewage, Susara Ruwan Kumara; Ryu, Yea Seong; Oh, Min Chang; Kwon, Taeg Kyu; Chae, Sungwook; Hyun, Jin Won

    2016-07-01

    Fisetin (3,3',4',7-tetrahydroxyflavone), a dietary flavonoid compound, is currently being investigated for its anticancer effect in various cancer models, including lung cancer. Recent studies show that fisetin induces cell growth inhibition and apoptosis in the human non-small cell lung cancer line NCI-H460. In this study, we investigated whether fisetin can induce endoplasmic reticulum (ER) stress-mediated apoptosis in NCI-H460 cells. Fisetin induced mitochondrial reactive oxygen species (ROS) and characteristic signs of ER stress: ER staining; mitochondrial Ca(2+) overload; expression of ER stress-related proteins; glucose-regulated protein (GRP)-78, phosphorylation of protein kinase RNA (PKR)-like endoplasmic reticulum kinase (PERK) and phosphorylation of eukaryotic initiation factor-2 α subunit; cleavage of activating transcription factor-6; phosphorylation of inositol-requiring kinase-1 and splicing of X-box transcription factor-1; induction of C/EBP homologous protein and cleaved caspase-12. siRNA-mediated knockdown of CHOP and ATF-6 attenuated fisetin-induced apoptotic cell death. In addition, fisetin induced phosphorylation of ERK, JNK, and p38 MAPK. Moreover, silencing of the MAPK signaling pathway prevented apoptotic cell death. In summary, our results indicate that, in NCI-H460 cells, fisetin induces apoptosis and ER stress that is mediated by induction of the MAPK signaling pathway.

  12. Vildagliptin preserves the mass and function of pancreatic β cells via the developmental regulation and suppression of oxidative and endoplasmic reticulum stress in a mouse model of diabetes.

    Science.gov (United States)

    Hamamoto, S; Kanda, Y; Shimoda, M; Tatsumi, F; Kohara, K; Tawaramoto, K; Hashiramoto, M; Kaku, K

    2013-02-01

    We investigated the molecular mechanisms by which vildagliptin preserved pancreatic β cell mass and function. Morphological, biochemical and gene expression profiles of the pancreatic islets were investigated in male KK-A(y) -TaJcl(KK-A(y) ) and C57BL/6JJcl (B6) mice aged 8 weeks which received either vildagliptin or a vehicle for 4 weeks. Body weight, food intake, fasting blood glucose, plasma insulin and active glucagon-like peptide-1 were unchanged with vildagliptin treatment in both mice. In KK-A(y) mice treated with vildagliptin, increased plasma triglyceride (TG) level and islet TG content were decreased, insulin sensitivity significantly improved, and the glucose tolerance ameliorated with increases in plasma insulin levels. Furthermore, vildagliptin increased glucose-stimulated insulin secretion, islet insulin content and pancreatic β cell mass in both strains. By vildagliptin, the expression of genes involved in cell differentiation/proliferation was upregulated in both strains, those related to apoptosis, endoplasmic reticulum stress and lipid synthesis was decreased and those related to anti-apoptosis and anti-oxidative stress was upregulated, in KK-A(y) mice. The morphological results were consistent with the gene expression profiles. Vildagliptin increases β cell mass by not only directly affecting cell kinetics but also by indirectly reducing cell apoptosis, oxidative stress and endoplasmic reticulum stress in diabetic mice. © 2012 Blackwell Publishing Ltd.

  13. Critical Role of Endoplasmic Reticulum Stress in Chronic Intermittent Hypoxia-Induced Deficits in Synaptic Plasticity and Long-Term Memory.

    Science.gov (United States)

    Xu, Lin-Hao; Xie, Hui; Shi, Zhi-Hui; Du, Li-Da; Wing, Yun-Kwok; Li, Albert M; Ke, Ya; Yung, Wing-Ho

    2015-09-20

    This study examined the role of endoplasmic reticulum (ER) stress in mediating chronic intermittent hypoxia (IH)-induced neurocognitive deficits. We designed experiments to demonstrate that ER stress is initiated in the hippocampus under chronic IH and determined its role in apoptotic cell death, impaired synaptic structure and plasticity, and memory deficits. Two weeks of IH disrupted ER fine structure and upregulated ER stress markers, glucose-regulated protein 78, caspase-12, and C/EBP homologous protein, in the hippocampus, which could be suppressed by ER stress inhibitors, tauroursodeoxycholic acid (TUDCA) and 4-phenylbutyric acid. Meanwhile, ER stress induced apoptosis via decreased Bcl-2, promoted reactive oxygen species production, and increased malondialdehyde formation and protein carbonyl, as well as suppressed mitochondrial function. These effects were largely prevented by ER stress inhibitors. On the other hand, suppression of oxidative stress could reduce ER stress. In addition, the length of the synaptic active zone and number of mature spines were reduced by IH. Long-term recognition memory and spatial memory were also impaired, which was accompanied by reduced long-term potentiation in the Schaffer collateral pathway. These effects were prevented by coadministration of the TUDCA. These results show that ER stress plays a critical role in underlying memory deficits in obstructive sleep apnea (OSA)-associated IH. Attenuators of ER stress may serve as novel adjunct therapeutic agents for ameliorating OSA-induced neurocognitive impairment.

  14. A micromachined surface stress sensor with electronic readout

    NARCIS (Netherlands)

    Carlen, E.T.; Weinberg, M.S.; Zapata, A.M.; Borenstein, J.T.

    2008-01-01

    A micromachined surface stress sensor has been fabricated and integrated off chip with a low-noise, differential capacitance, electronic readout circuit. The differential capacitance signal is modulated with a high frequency carrier signal, and the output signal is synchronously demodulated and filt

  15. 内质网应激在青光眼中作用的研究进展%The progress of study about endoplasmic reticulum stress in glaucoma

    Institute of Scientific and Technical Information of China (English)

    胡婕; 江冰

    2016-01-01

    In eukaryotic cells,the most secreted proteins and membrane proteins are compounded,modified and folded into the correct structure in the endoplasmic reticulum.Only correctly folded proteins can be transported to the golgi apparatus for further processing.If the endoplasmic reticulum is insufficient to deal with the accumulation of unfolded or misfolded proteins,balance will be broken,and endoplasmic reticulum stress (ERS) will be started.To eliminate the unfolded proteins,cells will activate unfolded protein response (UPR) immediately for self-protection.If the induced ERS is strong or persistent,the UPR could not maintain the balance of homeostasis in endoplasmic reticulum.Then the ERS will lead to C/EBP homologous protein activation and initiate cell apoptosis.The continuous ERS may participate in the occurrence and development of many diseases,such as neurodegenerative diseases and type 2 diabetes.In this article,the research progress of ERS and its relationship with glaucoma is reviewed.%近年研究发现内质网应激参与了众多疾病的发病.细胞发生内质网应激的最终结局取决于内质网应激程度和未折叠蛋白质反应维持自身稳态能力两者间的动态平衡.本文从小梁网细胞和青光眼神经传导通路两个方面,探讨了内质网应激与青光眼疾病发生、发展的可能作用机制,并针对目前已发现的治疗新靶点进行综述.

  16. Fluoxetine synergizes with temozolomide to induce the CHOP-dependent endoplasmic reticulum stress-related apoptosis pathway in glioma cells.

    Science.gov (United States)

    Ma, Jian; Yang, Yan-Ru; Chen, Wei; Chen, Mei-Hua; Wang, Hao; Wang, Xiao-Dan; Sun, Li-Li; Wang, Feng-Ze; Wang, De-Cai

    2016-08-01

    Although temozolomide (TMZ) is the most effective chemotherapy agent for glioma, chemotherapy resistance has limited its clinical use. Fluoxetine (FLT), which is widely used in cancer-related depression, has exhibited potent anticancer properties in different cancer cell types. The aim of this study was i) to evaluate the antitumor mechanism of FLT, and ii) to further evaluate the effects of a combination of FLT and TMZ on glioma cells. Glioma cell lines were exposed to FLT and/or TMZ. Cell viability and apoptosis were examined by CCK-8 assay, flow cytometry and caspase-3 activity assay, respectively. The expression of endoplasmic reticulum-stress (ERS) apoptosis-related proteins was measured using real-time PCR and western blotting. Synergism between the two drugs was evaluated by the combination index (CI) through CompuSyn software. FLT significantly and dose-dependently inhibited the proliferation of various glioma cell lines, and rat glioma C6 cells had a highly sensitive response to the addition of FLT. FLT treatment increased the early apoptosis rate, induced typical apoptotic morphology in the C6 cells and activated caspase-3 with no change in the mitochondrial membrane potential. Further study showed that FLT activated the ERS marker, CHOP. This induction was associated with activation of the PERK-eIF2α-ATF4 and ATF6 cascade. Concomitantly, GADD34, a downstream molecule of CHOP, was also increased. Combined FLT and TMZ treatment showed a synergistic cytotoxic effect in the C6 glioma cells. Knockdown of CHOP expression abolished the synergistic effect of FLT and TMZ in the C6 cells, which suggests that FLT may sensitize glioma cells to TMZ through activation of the CHOP-dependent apoptosis pathway. These results revealed that FLT induced glioma cell apoptosis and sensitized glioma cells to TMZ through activation of the CHOP‑dependent apoptosis pathway. The present study provides a primary basis for using the combination of these drugs in patients with

  17. Monocytes, endoplasmic reticulum stress and metabolomics in dogs with multiple organ dysfunction syndrome treated by continuous venovenous hemodiafiltration

    Science.gov (United States)

    Xu, Yun-Peng; Sui, Xiao-Lu; Zhang, Ai-Sha; Ye, Lei; Gu, Feng-Juan; Chen, Ji-Hong

    2017-01-01

    Objectives We tried to investigate the mechanism of continuous venovenous hemodiafiltration (CVVHDF) treatment in monocytes function, endoplasmic reticulum (ER) stress signaling pathways, metabolomics and histopathological changes of MODS dogs, and aimed to enhance the understanding of pathogenesis and provide novel avenues to potential therapies. Methods 12 male Beagle dogs were used to develop the stable models of MODS by using hemorrhagic shock plus resuscitation and endotoxemia, and assigned randomly to CVVHDF group (n=6) and MODS group (n=6). The dogs in CVVHDF group were given the typical CVVHDF treatment for 24h after the completion of endotoxin intravenous infusion, while those in MODS group were offered the i.v heparin instead only. Serum sample were collected at five time points, i.e. before anesthesia, 0h, 6h, 12h and 24h after the endotoxin injection (T1˜T5, respectively), and meanwhile, the changes of mRNA, protein and human umbilical vein endothelial cells (HUVECs) apoptosis rates in JNK, CHOP and Caspase-12 were observed before and after interfered by RNA interference technology. Results The levels of DLA-DR, IL-1β and IL-4 were higher than those in MODS group after the CVVHDF treatment, and the early and late apoptosis rates showed downward trend compared with MODS group. In vitro and prior to RNA interference (RNAi), the levels of mRNA and protein expression and HUVECs apoptosis rates of JNK, CHOP and Caspase-12 in CVVHDF group were significantly lower compared to T1 and MODS group respectively. However, the levels of mRNA and protein expression and HUVECs apoptosis rates were significantly lower than those before interfered by RNAi in both two groups. The serum levels of LPCs, ornithine, proline, methionine, etc. were down-regulated while carnitines, FFAs, PC, etc. were increased significantly in MODS (T4), and the serum levels of methionine, proline, arginine and lysine were increased while carnitine, LPCs, PCs, SMs and orthophosporic acid were

  18. Adiponectin protects the genioglossus of rats against chronic intermittent hypoxia-induced injury via inhibition of endoplasmic reticulum stress

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-feng; HUANG Han-peng; DING Wen-xiao; DING Ning; LU Gan; LIU Jian-nan; ZHANG Xi-long

    2013-01-01

    Background Obstructive sleep apnea hypopnea syndrome,characterized by chronic intermittent hypoxia (CIH),is closely correlated with genioglossus dysfunction.CIH has been identified to mediate mitochondrial damage in genioglossus.It has been reported that endoplasmic reticulum stress (ERS) could be induced by mitochondrial dysfunction.This study aimed to investigate the role of ERS in CIH-induced genioglossus injury,as well as the possible intervention effect of adiponectin (Ad) supplement in rats.Methods Forty-five male Wistar rats were randomly divided into three groups and submitted to room air (group A,n=15) as a control or CIH (groups B and C,n=15,respectively).Throughout the exposure period,intravenous Ad was given in group C; while intravenous normal saline was simultaneously given in groups A and B.After 35-day exposure,genioglossus samples were obtained from the pentobarbital-anaesthetized rats via surgical dissection,following blood sampling.Western blotting was applied to detect expressions of ERS signals and associated apoptotic pathways in genioglossus.Serum adiponectin levels were assessed via enzyme-linked immunosorbent assay (ELISA).Results Significant hypoadiponectinemia was revealed in group B only (P <0.05).Compared to those in groups A and C,expressions of markers involved in ERS,such as glucose regulated protein 78 (GRP78),p-PERK,phosphorylated eukaryotic initiation factor 2α (p-elF2α),phosphorylated inositol-requiring transmembrane kinase/endoribonuclease 1α (p-IRE1α),spliced X-Box binding protein 1 (XBP1s) and activating transcription factor 6 (ATF6),were significantly enhanced in group B (all P <0.01); while no significant difference was shown between groups A and C (all P >0.05).ERS-associated apoptotic pathways were remarkably activated in group B.The involved markers detected as the expression of CCAAT/enhancer binding protein homologous protein (CHOP),B-cell lymphoma/leukemia associatied X protein (BAX)and caspase-12 were

  19. A common genetic variation of melanoma inhibitory activity-2 labels a subtype of pancreatic adenocarcinoma with high endoplasmic reticulum stress levels

    OpenAIRE

    Erkan, Murat Mert; Kong, Bo; Wu, Weiwei; Valkovska, Nataliya; Jager, Carsten; Hong, Xin; Nitsche, Ulrich; Friess, Helmut; Esposito, Irene; Kleeff, Joerg; Michalski, Christoph W.

    2015-01-01

    A common genetic variation of melanoma inhibitory activity-2 labels a subtype of pancreatic adenocarcinoma with high endoplasmic reticulum stress levels Bo Kong1, Weiwei Wu1, Nataliya Valkovska1, Carsten Ja¨ger1, Xin Hong1, Ulrich Nitsche1, Helmut Friess1, Irene Esposito2, Mert Erkan3, Jo¨rg Kleeff1* & Christoph W. Michalski4* 1Department of Surgery, Technische Universita¨t Mu¨nchen, Munich, Germany, 2Institute of Pathology, Technische Universita¨t Mu¨nchen, Munich, Ge...

  20. The endoplasmic reticulum stress inducer thapsigargin enhances the toxicity of ZnO nanoparticles to macrophages and macrophage-endothelial co-culture.

    Science.gov (United States)

    Chen, Gui; Shen, Yuexin; Li, Xiyue; Jiang, Qin; Cheng, Shanshan; Gu, Yuxiu; Liu, Liangliang; Cao, Yi

    2017-03-01

    It was recently shown that exposure to ZnO nanoparticles (NPs) could induce endoplasmic reticulum (ER) stress both in vivo and in vitro, but the role of ER stress in ZnO NP induced toxicity remains unclear. Because macrophages are sensitive to ER stress, we hypothesized that stressing macrophages with ER stress inducer could enhance the toxicity of ZnO NPs. In this study, the effects of ER stress inducer thapsigargin (TG) on the toxicity of ZnO NPs to THP-1 macrophages were investigated. The results showed that TG enhanced ZnO NP induced cytotoxicity as revealed by water soluble tetrazolium-1 (WST-1) and neutral red uptake assays, but not lactate dehydrogenase (LDH) assay. ZnO NPs dose-dependently enhanced the accumulation of intracellular Zn ions without the induction of reactive oxygen species (ROS), and the presence of TG did not significantly affect these effects. In the co-culture, exposure of THP-1 macrophages in the upper chamber to ZnO NPs and TG significantly reduced the viability of human umbilical vein endothelial cells (HUVECs) in the lower chamber, but the release of tumor necrosis factor α (TNFα) was not induced. In summary, our data showed that stressing THP-1 macrophages with TG enhanced the cytotoxicity of ZnO NPs to macrophages and macrophage-endothelial co-cultures.

  1. Inhibiting autophagy promotes endoplasmic reticulum stress and the ROS‑induced nod‑like receptor 3‑dependent proinflammatory response in HepG2 cells.

    Science.gov (United States)

    Yin, Jia-Jing; Xie, Guangying; Zhang, Ning; Li, Yanbo

    2016-10-01

    Inflammation and endoplasmic reticulum (ER) stress are key contributors to insulin resistance and metabolic disease, and interleukin (IL)‑1β is involved in insulin resistance. The present study aimed to investigated the role of autophagy in LPS‑induced ER stress and inflammation, which may provide evidence for controlling metabolic disease associated with inflammation. Lipopolysaccharide (LPS) induced the activation of ER stress and the nod‑like receptor 3‑dependent expression of IL‑1β and caspase‑1, as shown by western blotting, which contributed to HepG2 cell death. This also involved the generation of mitochondrial reactive oxygen species and the autophagy signaling response, which are derived from the ER stress pathway. The percentage of apoptotic cells was measured by flow cytometry with fluorescein isothiocyanate/propidium iodide staining. Reactive oxygen species formation was detected by flow cytometry using the peroxide sensitive fluorescent probe 2',7'‑dichlorofluorescin diacetate. Autophagy activation was measured by western blotting and confirmed using transmission electron microscopy. Furthermore, inhibiting autophagy promoted ER stress and the proinflammatory response in addition to cell death. These findings provide insights into the protective role of autophagy in LPS‑induced cell death and ER stress, and further identified the association of autophagy, ER stress and inflammation in HepG2 cells.

  2. Hypoxia-triggered m-calpain activation evokes endoplasmic reticulum stress and neuropathogenesis in a transgenic mouse model of Alzheimer's disease.

    Science.gov (United States)

    Wang, Chun-Yan; Xie, Jing-Wei; Wang, Tao; Xu, Ye; Cai, Jian-Hui; Wang, Xu; Zhao, Bao-Lu; An, Li; Wang, Zhan-You

    2013-10-01

    Previous studies have demonstrated that endoplasmic reticulum (ER) stress is activated in Alzheimer's disease (AD) brains. ER stress-triggered unfolded protein response (UPR) leads to tau phosphorylation and neuronal death. In this study, we tested the hypothesis that hypoxia-induced m-calpain activation is involved in ER stress-mediated AD pathogenesis. We employed a hypoxic exposure in APP/PS1 transgenic mice and SH-SY5Y cells overexpressing human Swedish mutation APP (APPswe). We observed that hypoxia impaired spatial learning and memory in the APP/PS1 mouse. In the transgenic mouse brain, hypoxia increased the UPR, upregulated apoptotic signaling, enhanced the activation of calpain and glycogen synthase kinase-3β (GSK3β), and increased tau hyperphosphorylation and β-amyloid deposition. In APPswe cells, m-calpain silencing reduced hypoxia-induced cellular dysfunction and resulted in suppression of GSK3β activation, ER stress and tau hyperphosphorylation reduction as well as caspase pathway suppression. These findings demonstrate that hypoxia-induced abnormal calpain activation may increase ER stress-induced apoptosis in AD pathogenesis. In contrast, a reduction in the expression of the m-calpain isoform reduces ER stress-linked apoptosis that is triggered by hypoxia. These findings suggest that hypoxia-triggered m-calpain activation is involved in ER stress-mediated AD pathogenesis. m-calpain is a potential target for AD therapeutics. © 2013 John Wiley & Sons Ltd.

  3. Effect of Cudrania tricuspidata and Kaempferol in Endoplasmic Reticulum Stress-Induced Inflammation and Hepatic Insulin Resistance in HepG2 Cells.

    Science.gov (United States)

    Kim, Ok-Kyung; Jun, Woojin; Lee, Jeongmin

    2016-01-21

    In this study, we quantitated kaempferol in water extract from Cudrania tricuspidata leaves (CTL) and investigated its effects on endoplasmic reticulum (ER) stress-induced inflammation and insulin resistance in HepG2 cells. The concentration of kaempferol in the CTL was 5.07 ± 0.08 mg/g. The HepG2 cells were treated with 300 µg/mL of CTL, 500 µg/mL of CTL, 1.5 µg/mL of kaempferol or 2.5 µg/mL of kaempferol, followed immediately by stimulation with 100 nM of thapsigargin for ER stress induction for 24 h. There was a marked increase in the activation of the ER stress and inflammation response in the thapsigargin-stimulated control group. The CTL treatment interrupted the ER stress response and ER stress-induced inflammation. Kaempferol partially inhibited the ER stress response and inflammation. There was a significant increase in serine phosphorylation of insulin receptor substrate (IRS)-1 and the expression of C/EBPα and gluconeogenic genes in the thapsigargin-stimulated control group compared to the normal control. Both CTL and kaempferol suppressed serine phosphorylation of IRS-1, and the treatments did not interrupt the C/EBPα/gluconeogenic gene pathway. These results suggest that kaempferol might be the active compound of CTL and that it might protect against ER stress-induced inflammation and hyperglycemia.

  4. Synoviolin inhibitor LS-102 reduces endoplasmic reticulum stress-induced collagen secretion in an in vitro model of stress-related interstitial pneumonia.

    Science.gov (United States)

    Nakajima, Fukami; Aratani, Satoko; Fujita, Hidetoshi; Yagishita, Naoko; Ichinose, Shizuko; Makita, Koshi; Setoguchi, Yasuhiro; Nakajima, Toshihiro

    2015-01-01

    The deletion mutation of exon 4 in surfactant protein C (SP-C), a lung surfactant protein, has been identified in parent-child cases of familial interstitial pneumonia. It has been shown that this mutation induces endoplasmic reticulum (ER) stress. Synoviolin is an E3 ubiquitin ligase that is localized to the ER and is an important factor in the degradation of ER-related proteins. It has been demonstrated that synoviolin is involved in liver fibrosis. In the present study, we investigated the involvement of synoviolin in the pathogenesis of interstitial pneumonia caused by the exon 4 deletion in the SP-C gene. We transfected wild-type and exon 4-deleted SP-C genes into A549 human lung adenocarcinoma cells and measured the secretion of collagen, which is a representative extracellular matrix protein involved in fibrosis. Secreted collagen levels were increased in the culture medium in SP-C mutants compared to the wild-type cells. Furthermore, the transcription of mRNAs coding for factors associated with fibrosis was increased. Subsequently, to assess the involvement of synoviolin, we constructed plasmids with a luciferase gene under the control of the synoviolin promoter. The A549 cells were transfected with the construct along with the exon 4-deleted SP-C plasmid for use in the luciferase assay. We found a 1.6-fold increase in luciferase activity in the cells carrying exon 4 deleted SP-C, as well as an increase in intrinsic synoviolin expression at the mRNA and protein levels. Collagen secretion was decreased by the addition of LS-102, a synoviolin inhibitor, to the A549 culture medium following transfection with wild-type and exon 4-deleted SP-C. These results demonstrate that synoviolin is involved in the onset of interstitial pneumonia induced by exon 4-deleted SP-C, which suggests that synoviolin inhibitors may be used in the treatment of the disease.

  5. Triggering apoptotic death of human epidermal keratinocytes by malic Acid: involvement of endoplasmic reticulum stress- and mitochondria-dependent signaling pathways.

    Science.gov (United States)

    Hsiao, Yu-Ping; Lai, Wan-Wen; Wu, Shi-Bei; Tsai, Chung-Hung; Tang, Sheau-Chung; Chung, Jing-Gung; Yang, Jen-Hung

    2015-01-09

    Malic acid (MA) has been commonly used in cosmetic products, but the safety reports in skin are sparse. To investigate the biological effects of MA in human skin keratinocytes, we investigated the potential cytotoxicity and apoptotic effects of MA in human keratinocyte cell lines (HaCaT). The data showed that MA induced apoptosis based on the observations of DAPI staining, DNA fragmentation, and sub-G1 phase in HaCaT cells and normal human epidermal keratinocytes (NHEKs). Flow cytometric assays also showed that MA increased the production of mitochondrial superoxide (mito-SOX) but decreased the mitochondrial membrane potential. Analysis of bioenergetics function with the XF 24 analyzer Seahorse extracellular flux analyzer demonstrated that oxygen consumption rate (OCR) was significantly decreased whereas extracellular acidification rate (ECAR) was increased in MA-treated keratinocytes. The occurrence of apoptosis was proved by the increased expressions of FasL, Fas, Bax, Bid, caspases-3, -8, -9, cytochrome c, and the declined expressions of Bcl-2, PARP. MA also induced endoplasmic reticulum stress associated protein expression such as GRP78, GADD153, and ATF6α. We demonstrated that MA had anti-proliferative effect in HaCaT cell through the inhibition of cell cycle progression at G0/G1, and the induction of programmed cell death through endoplasmic reticulum stress- and mitochondria-dependent pathways.

  6. Triggering Apoptotic Death of Human Epidermal Keratinocytes by Malic Acid: Involvement of Endoplasmic Reticulum Stress- and Mitochondria-Dependent Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Yu-Ping Hsiao

    2015-01-01

    Full Text Available Malic acid (MA has been commonly used in cosmetic products, but the safety reports in skin are sparse. To investigate the biological effects of MA in human skin keratinocytes, we investigated the potential cytotoxicity and apoptotic effects of MA in human keratinocyte cell lines (HaCaT. The data showed that MA induced apoptosis based on the observations of DAPI staining, DNA fragmentation, and sub-G1 phase in HaCaT cells and normal human epidermal keratinocytes (NHEKs. Flow cytometric assays also showed that MA increased the production of mitochondrial superoxide (mito-SOX but decreased the mitochondrial membrane potential. Analysis of bioenergetics function with the XF 24 analyzer Seahorse extracellular flux analyzer demonstrated that oxygen consumption rate (OCR was significantly decreased whereas extracellular acidification rate (ECAR was increased in MA-treated keratinocytes. The occurrence of apoptosis was proved by the increased expressions of FasL, Fas, Bax, Bid, caspases-3, -8, -9, cytochrome c, and the declined expressions of Bcl-2, PARP. MA also induced endoplasmic reticulum stress associated protein expression such as GRP78, GADD153, and ATF6α. We demonstrated that MA had anti-proliferative effect in HaCaT cell through the inhibition of cell cycle progression at G0/G1, and the induction of programmed cell death through endoplasmic reticulum stress- and mitochondria-dependent pathways.

  7. C1q/TNF-Related Protein 9 Protects Diabetic Rat Heart against Ischemia Reperfusion Injury: Role of Endoplasmic Reticulum Stress

    Science.gov (United States)

    Bai, Sanxing; Cheng, Liang; Yang, Yang; Fan, Chongxi; Zhao, Dajun; Qin, Zhigang; Feng, Xiao; Zhao, Lin; Ma, Jipeng; Wang, Xiaowu; Yang, Jian; Xu, Xuezeng

    2016-01-01

    As a newly identified adiponectin paralog, C1q/TNF-related protein 9 (CTRP9) reduces myocardial ischemia reperfusion (IR) injury through partially understood mechanisms. In the present study, we sought to identify the role of endoplasmic reticulum stress (ERS) in CTRP9 induced cardioprotection in diabetic heart. Isolated hearts from high-fat-diet (HFD) induced type 2 diabetic Sprague-Dawley rats were subjected to ex vivo IR protocol via a Langendorff apparatus at the presence of globular CTRP9. CTRP9 significantly improved post-IR heart function and reduced cardiac infarction, cardiomyocytes apoptosis, Caspase-3, Caspase-9, Caspase-12, TNF-α expression, and lactate dehydrogenase activity. The cardioprotective effect of CTRP9 was associated with reduced ERS and increased expression of disulfide-bond A oxidoreductase-like protein (DsbA-L) in diabetic heart. CTRP9 reduced ERS in thapsigargin (TG) treated cardiomyocytes and protected endoplasmic reticulum (ER) stressed H9c2 cells against simulated ischemia reperfusion (SIR) injury, concurrent with increased expression of DsbA-L. Knockdown of DsbA-L increased ERS and attenuated CTRP9 induced protection against SIR injury in H9c2 cells. Our findings demonstrated for the first time that CTRP9 exerts cardioprotection by reducing ERS in diabetic heart through increasing DsbA-L.

  8. Endoplasmic Reticulum Stress and NF-[Formula: see text]B Pathway in Salidroside Mediated Neuroprotection: Potential of Salidroside in Neurodegenerative Diseases.

    Science.gov (United States)

    Wang, Chenggui; Lou, Yiting; Xu, Jianxiang; Feng, Zhenhua; Chen, Yu; Tang, Qian; Wang, Qingqing; Jin, Haiming; Wu, Yaosen; Tian, Naifeng; Zhou, Yifei; Xu, Huazi; Zhang, Xiaolei

    2017-09-25

    Microglial activation leads to increased production of proinflammatory enzymes and cytokines, which is considered to play crucial role in neurodegenerative diseases, however there are only a few drugs that target microglia activation. Recent studies have indicated that the Traditional Chinese Medicine, salidroside (Sal), exerted anti-inflammatory effects. According to this evidence, our present study aims to explore the effect of the Sal (a phenylpropanoid glycoside compound which is isolated from rhodiola), on microglia activation in lipopolysaccharide (LPS)-stimulated BV-2 cells. Our results showed that Sal could significantly