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Sample records for er stress-chop pathway

  1. High-density lipoprotein inhibits ox-LDL-induced adipokine secretion by upregulating SR-BI expression and suppressing ER Stress pathway.

    PubMed

    Song, Guohua; Wu, Xia; Zhang, Pu; Yu, Yang; Yang, Mingfeng; Jiao, Peng; Wang, Ni; Song, Haiming; Wu, You; Zhang, Xiangjian; Liu, Huaxia; Qin, Shucun

    2016-07-29

    Endoplasmic reticulum stress (ERS) in adipocytes can modulate adipokines secretion. The aim of this study was to explore the protective effect of high-density lipoprotein (HDL) on oxidized low-density lipoprotein (ox-LDL)-induced ERS-C/EBP homologous protein (CHOP) pathway-mediated adipokine secretion. Our results showed that serum adipokines, including visfatin, resistin and TNF-α, correlated inversely with serum HDL cholesterol level in patients with abdominal obesity. In vitro, like ERS inhibitor 4-phenylbutyric acid (PBA), HDL inhibited ox-LDL- or tunicamycin (TM, an ERS inducer)-induced increase in visfatin and resistin secretion. Moreover, HDL inhibited ox-LDL-induced free cholesterol (FC) accumulation in whole cell lysate and in the endoplasmic reticulum. Additionally, like PBA, HDL inhibited ox-LDL- or TM-induced activation of ERS response as assessed by the decreased phosphorylation of protein kinase-like ER kinase and eukaryotic translation initiation factor 2α and reduced nuclear translocation of activating transcription factor 6 as well as the downregulation of Bip and CHOP. Furthermore, HDL increased scavenger receptor class B type I (SR-BI) expression and SR-BI siRNA treatment abolished the inhibitory effects of HDL on ox-LDL-induced FC accumulation and CHOP upregulation. These data indicate that HDL may suppress ox-LDL-induced FC accumulation in adipocytes through upregulation of SR-BI, subsequently preventing ox-LDL-induced ER stress-CHOP pathway-mediated adipocyte inflammation.

  2. High-density lipoprotein inhibits ox-LDL-induced adipokine secretion by upregulating SR-BI expression and suppressing ER Stress pathway

    PubMed Central

    Song, Guohua; Wu, Xia; Zhang, Pu; Yu, Yang; Yang, Mingfeng; Jiao, Peng; Wang, Ni; Song, Haiming; Wu, You; Zhang, Xiangjian; Liu, Huaxia; Qin, Shucun

    2016-01-01

    Endoplasmic reticulum stress (ERS) in adipocytes can modulate adipokines secretion. The aim of this study was to explore the protective effect of high-density lipoprotein (HDL) on oxidized low-density lipoprotein (ox-LDL)-induced ERS-C/EBP homologous protein (CHOP) pathway-mediated adipokine secretion. Our results showed that serum adipokines, including visfatin, resistin and TNF-α, correlated inversely with serum HDL cholesterol level in patients with abdominal obesity. In vitro, like ERS inhibitor 4-phenylbutyric acid (PBA), HDL inhibited ox-LDL- or tunicamycin (TM, an ERS inducer)-induced increase in visfatin and resistin secretion. Moreover, HDL inhibited ox-LDL-induced free cholesterol (FC) accumulation in whole cell lysate and in the endoplasmic reticulum. Additionally, like PBA, HDL inhibited ox-LDL- or TM-induced activation of ERS response as assessed by the decreased phosphorylation of protein kinase-like ER kinase and eukaryotic translation initiation factor 2α and reduced nuclear translocation of activating transcription factor 6 as well as the downregulation of Bip and CHOP. Furthermore, HDL increased scavenger receptor class B type I (SR-BI) expression and SR-BI siRNA treatment abolished the inhibitory effects of HDL on ox-LDL-induced FC accumulation and CHOP upregulation. These data indicate that HDL may suppress ox-LDL-induced FC accumulation in adipocytes through upregulation of SR-BI, subsequently preventing ox-LDL-induced ER stress-CHOP pathway-mediated adipocyte inflammation. PMID:27468698

  3. The ER Stress Surveillance (ERSU) pathway regulates daughter cell ER protein aggregate inheritance.

    PubMed

    Piña, Francisco J; Niwa, Maho

    2015-09-01

    Stress induced by cytoplasmic protein aggregates can have deleterious consequences for the cell, contributing to neurodegeneration and other diseases. Protein aggregates are also formed within the endoplasmic reticulum (ER), although the fate of ER protein aggregates, specifically during cell division, is not well understood. By simultaneous visualization of both the ER itself and ER protein aggregates, we found that ER protein aggregates that induce ER stress are retained in the mother cell by activation of the ER Stress Surveillance (ERSU) pathway, which prevents inheritance of stressed ER. In contrast, under conditions of normal ER inheritance, ER protein aggregates can enter the daughter cell. Thus, whereas cytoplasmic protein aggregates are retained in the mother cell to protect the functional capacity of daughter cells, the fate of ER protein aggregates is determined by whether or not they activate the ERSU pathway to impede transmission of the cortical ER during the cell cycle.

  4. The ER Stress Surveillance (ERSU) pathway regulates daughter cell ER protein aggregate inheritance

    PubMed Central

    Piña, Francisco J; Niwa, Maho

    2015-01-01

    Stress induced by cytoplasmic protein aggregates can have deleterious consequences for the cell, contributing to neurodegeneration and other diseases. Protein aggregates are also formed within the endoplasmic reticulum (ER), although the fate of ER protein aggregates, specifically during cell division, is not well understood. By simultaneous visualization of both the ER itself and ER protein aggregates, we found that ER protein aggregates that induce ER stress are retained in the mother cell by activation of the ER Stress Surveillance (ERSU) pathway, which prevents inheritance of stressed ER. In contrast, under conditions of normal ER inheritance, ER protein aggregates can enter the daughter cell. Thus, whereas cytoplasmic protein aggregates are retained in the mother cell to protect the functional capacity of daughter cells, the fate of ER protein aggregates is determined by whether or not they activate the ERSU pathway to impede transmission of the cortical ER during the cell cycle. DOI: http://dx.doi.org/10.7554/eLife.06970.001 PMID:26327697

  5. Emerging Roles of ER Stress and Unfolded Protein Response Pathways in Skeletal Muscle Health and Disease.

    PubMed

    Bohnert, Kyle R; McMillan, Joseph D; Kumar, Ashok

    2017-02-08

    Skeletal muscle is the most abundant tissue in the human body and can adapt its mass as a consequence of physical activity, metabolism, growth factors, and disease conditions. Skeletal muscle contains an extensive network of endoplasmic reticulum (ER), called sarcoplasmic reticulum, which plays an important role in the regulation of proteostasis and calcium homeostasis. In many cell types, environmental and genetic factors that disrupt ER function cause an accumulation of misfolded and unfolded proteins in the ER lumen that ultimately leads to ER stress. To alleviate the stress and restore homeostasis, the ER activates a signaling network called the unfolded protein response (UPR). The UPR has three arms, which regulate protein synthesis and expression of many ER chaperone and regulatory proteins. However, the role of individual UPR pathways in skeletal muscle has just begun to be investigated. Recent studies suggest that UPR pathways play pivotal roles in muscle stem cell homeostasis, myogenic differentiation, and regeneration of injured skeletal muscle. Moreover, markers of ER stress and the UPR are activated in skeletal muscle in diverse conditions such as exercise, denervation, starvation, high fat diet, cancer cachexia, and aging. Accumulating evidence also suggests that ER stress may have important roles in the pathogenesis of inflammatory myopathies and genetic muscle disorders. The purpose of this review article is to discuss the role and potential mechanisms by which ER stress and the individual arms of the UPR regulate skeletal muscle formation, plasticity, and function in various physiological and pathophysiological conditions. This article is protected by copyright. All rights reserved.

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

    PubMed

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

    2016-09-01

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

  7. Regulation of ER stress-induced autophagy by GSK3β-TIP60-ULK1 pathway

    PubMed Central

    Nie, Tiejian; Yang, Shaosong; Ma, Hongwei; Zhang, Lei; Lu, Fangfang; Tao, Kai; Wang, Ronglin; Yang, Ruixin; Huang, Lu; Mao, Zixu; Yang, Qian

    2016-01-01

    Endoplasmic reticulum (ER) stress is involved in many cellular processes. Emerging evidence suggests that ER stress can trigger autophagy; however, the mechanisms by which ER stress regulates autophagy and its role in this condition are not fully understood. HIV Tat-interactive protein, 60 kDa (TIP60) is a newly discovered acetyltransferase that can modulate autophagy flux by activating ULK1 upon growth factor deprivation. In this study, we investigated the mechanisms by which ER stress induces autophagy. We showed that ER stress activates glycogen synthase kinase-3β (GSK3β). This led to a GSK3β-dependent phosphorylation of TIP60, triggering a TIP60-mediated acetylation of ULK1 and activation of autophagy. Inhibition of either GSK3β or TIP60 acetylation activities significantly attenuated ER stress-induced autophagy. Moreover, enhancing the level of TIP60 attenuated the level of CHOP after ER stress, and reduced the ER stress-induced cell death. In contrast, expression of TIP60 mutant that could not be phosphorylated by GSK3β exacerbated the generation of CHOP and increased the ER stress-induced cell death. These findings reveal that ER stress engages the GSK3β-TIP60-ULK1 pathway to increase autophagy. Attenuation of this pathway renders cells more sensitive to and increases the toxicity of ER stress. PMID:28032867

  8. Cytolethal distending toxins require components of the ER-associated degradation pathway for host cell entry.

    PubMed

    Eshraghi, Aria; Dixon, Shandee D; Tamilselvam, Batcha; Kim, Emily Jin-Kyung; Gargi, Amandeep; Kulik, Julia C; Damoiseaux, Robert; Blanke, Steven R; Bradley, Kenneth A

    2014-07-01

    Intracellular acting protein exotoxins produced by bacteria and plants are important molecular determinants that drive numerous human diseases. A subset of these toxins, the cytolethal distending toxins (CDTs), are encoded by several Gram-negative pathogens and have been proposed to enhance virulence by allowing evasion of the immune system. CDTs are trafficked in a retrograde manner from the cell surface through the Golgi apparatus and into the endoplasmic reticulum (ER) before ultimately reaching the host cell nucleus. However, the mechanism by which CDTs exit the ER is not known. Here we show that three central components of the host ER associated degradation (ERAD) machinery, Derlin-2 (Derl2), the E3 ubiquitin-protein ligase Hrd1, and the AAA ATPase p97, are required for intoxication by some CDTs. Complementation of Derl2-deficient cells with Derl2:Derl1 chimeras identified two previously uncharacterized functional domains in Derl2, the N-terminal 88 amino acids and the second ER-luminal loop, as required for intoxication by the CDT encoded by Haemophilus ducreyi (Hd-CDT). In contrast, two motifs required for Derlin-dependent retrotranslocation of ERAD substrates, a conserved WR motif and an SHP box that mediates interaction with the AAA ATPase p97, were found to be dispensable for Hd-CDT intoxication. Interestingly, this previously undescribed mechanism is shared with the plant toxin ricin. These data reveal a requirement for multiple components of the ERAD pathway for CDT intoxication and provide insight into a Derl2-dependent pathway exploited by retrograde trafficking toxins.

  9. Sodium fluoride (NaF) induces the splenic apoptosis via endoplasmic reticulum (ER) stress pathway in vivo and in vitro

    PubMed Central

    Cui, Hengmin; Chen, Lian; Luo, Qin; Fang, Jing; Zuo, Zhicai; Deng, Junliang; Wang, Xun; Zhao, Ling

    2016-01-01

    At present, there are no reports on the relationship between fluoride-induced apoptosis and endoplasmic reticulum (ER) stress (ER stress) in the spleen of human and animals in vivo and in vitro. Therefore, the aim of this study was to define sodium fluoride (NaF)-induced apoptosis mediated by ER stress in the spleen of mice in vivo and in vitro. Apoptosis and expression levels of the ER stress-related proteins were detected by flow cytometry and western blot, respectively. The results showed that NaF treatment increased lymphocytes apoptosis, which was consistent with NaF-caused ER Stress. NaF-caused ER stress was characterized by up-regulating protein expression levels of glucose-regulated protein 78 (BiP) and glucose-regulated protein 94 (GRP94), and by activating unfolded protein response (UPR). The signaling pathway of ER stress-associated apoptosis was activated by up-regulating protein expression levels of cleaved cysteine aspartate specific protease-12 (cleaved caspase-12), growth arrest and DNA damage-inducible gene 153 (Gadd153/CHOP) and phosphorylation of JUN N-terminal kinase (p-JNK). Additionally, our in vitro study found that apoptotic rate was decreased with remarkable down-regulation of the cleaved caspase-12, CHOP, p-JNK after ER stress was inhibited by 4-Phenylbutyric acid (4-PBA) treatment. In conclusion, NaF-induced apoptosis may mediated by ER stress in the spleen. PMID:28039491

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

    PubMed

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

    2014-12-01

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

  11. A bacterial toxin and a non-enveloped virus hijack ER-to-cytosol membrane translocation pathways to cause disease

    PubMed Central

    He, Kaiyu; Ravindran, Madhu Sudhan; Tsai, Billy

    2016-01-01

    A dedicated network of cellular factors ensures that proteins translocated into the endoplasmic reticulum (ER) are folded correctly before they exit this compartment en route to other cellular destinations or for secretion. When proteins misfold, selective ER-resident enzymes and chaperones are recruited to rectify the protein-misfolding problem in order to maintain cellular proteostasis. However, when a protein becomes terminally misfolded, it is ejected into the cytosol and degraded by the proteasome via a pathway called ER-associated degradation (ERAD). Strikingly, toxins and viruses can hijack elements of the ERAD pathway to access the host cytosol and cause infection. This review focuses on emerging data illuminating the molecular mechanisms by which these toxic agents co-opt the ER-to-cytosol translocation process to cause disease. PMID:26362261

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

    PubMed

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

    2015-03-01

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

  13. Estradiol inhibits osteoblast apoptosis via promotion of autophagy through the ER-ERK-mTOR pathway.

    PubMed

    Yang, Yue-Hua; Chen, Ke; Li, Bo; Chen, Jiang-Wei; Zheng, Xin-Feng; Wang, Yu-Ren; Jiang, Sheng-Dan; Jiang, Lei-Sheng

    2013-11-01

    Estradiol could protect osteoblast against apoptosis, and apoptosis and autophagy were extensively and intimately connected. The aim of the present study was to test the hypothesis that autophagy was present in osteoblasts under serum deprivation and estrogen protected against osteoblast apoptosis via promotion of autophagy. MC3T3-E1 osteoblastic cells were cultured in a serum-free and phenol red-free minimal essential medium (α-MEM). Ultrastructural analysis, lysosomal activity assessment and monodansycadaverine (MDC) staining were employed to determine the presence of autophagy, and real time PCR was used to evaluate the expression of autophagic markers. Meanwhile, the osteoblasts were transferred in a serum-free and phenol red-free α-MEM containing either vehicle or estradiol. Apoptosis and autophagy was assessed by using the techniques of real-time PCR, Western blot, immunofluorescence assay, and flow cytometry. The possible pathway through which estrogen promoted autophagy in the serum-deprived osteoblasts was also investigated. Real-time PCR demonstrated the expression of LC3, beclin1 and ULK1 genes in osteoblasts under serum deprivation, and immunofluorescence assay verified high expression of proteins of these three autophagic bio-markers. Lysosomes and autolysosomes accumulated in the cytoplasm of osteoblasts were also detected under transmission electron microscopy, MDC staining and lysosomal activity assessment. Meanwhile, estradiol significantly decreased the expression of proteins of the bio-markers of apoptosis, and at the same time increased the expression of proteins of the bio-markers of autophagy in the serum-deprived osteoblasts. Furthermore, the estradiol-promoted autophagy in serum-deprived osteoblasts could be blocked by estrogen receptor (ER) antagonist (ICI 182780), and estradiol failed to rescue the cells pretreated with an inhibitor of vacuolar ATPase (bafilomycin A) from apoptosis. Serum deprivation resulted in apoptosis through

  14. Endoplasmic Reticulum (ER) Stress Induces Sirtuin 1 (SIRT1) Expression via the PI3K-Akt-GSK3β Signaling Pathway and Promotes Hepatocellular Injury.

    PubMed

    Koga, Tomoaki; Suico, Mary Ann; Shimasaki, Shogo; Watanabe, Eriko; Kai, Yukari; Koyama, Kosuke; Omachi, Kohei; Morino-Koga, Saori; Sato, Takashi; Shuto, Tsuyoshi; Mori, Kazutoshi; Hino, Shinjiro; Nakao, Mitsuyoshi; Kai, Hirofumi

    2015-12-18

    Sirtuin 1 (SIRT1), an NAD(+)-dependent histone deacetylase, plays crucial roles in various biological processes including longevity, stress response, and cell survival. Endoplasmic reticulum (ER) stress is caused by dysfunction of ER homeostasis and exacerbates various diseases including diabetes, fatty liver, and chronic obstructive pulmonary disease. Although several reports have shown that SIRT1 negatively regulates ER stress and ER stress-induced responses in vitro and in vivo, the effect of ER stress on SIRT1 is less explored. In this study, we showed that ER stress induced SIRT1 expression in vitro and in vivo. We further determined the molecular mechanisms of how ER stress induces SIRT1 expression. Surprisingly, the conventional ER stress-activated transcription factors XBP1, ATF4, and ATF6 seem to be dispensable for SIRT1 induction. Based on inhibitor screening experiments with SIRT1 promoter, we found that the PI3K-Akt-GSK3β signaling pathway is required for SIRT1 induction by ER stress. Moreover, we showed that pharmacological inhibition of SIRT1 by EX527 inhibited the ER stress-induced cellular death in vitro and severe hepatocellular injury in vivo, indicating a detrimental role of SIRT1 in ER stress-induced damage responses. Collectively, these data suggest that SIRT1 expression is up-regulated by ER stress and contributes to ER stress-induced cellular damage.

  15. Endoplasmic Reticulum (ER) Stress Induces Sirtuin 1 (SIRT1) Expression via the PI3K-Akt-GSK3β Signaling Pathway and Promotes Hepatocellular Injury*

    PubMed Central

    Koga, Tomoaki; Suico, Mary Ann; Shimasaki, Shogo; Watanabe, Eriko; Kai, Yukari; Koyama, Kosuke; Omachi, Kohei; Morino-Koga, Saori; Sato, Takashi; Shuto, Tsuyoshi; Mori, Kazutoshi; Hino, Shinjiro; Nakao, Mitsuyoshi; Kai, Hirofumi

    2015-01-01

    Sirtuin 1 (SIRT1), an NAD+-dependent histone deacetylase, plays crucial roles in various biological processes including longevity, stress response, and cell survival. Endoplasmic reticulum (ER) stress is caused by dysfunction of ER homeostasis and exacerbates various diseases including diabetes, fatty liver, and chronic obstructive pulmonary disease. Although several reports have shown that SIRT1 negatively regulates ER stress and ER stress-induced responses in vitro and in vivo, the effect of ER stress on SIRT1 is less explored. In this study, we showed that ER stress induced SIRT1 expression in vitro and in vivo. We further determined the molecular mechanisms of how ER stress induces SIRT1 expression. Surprisingly, the conventional ER stress-activated transcription factors XBP1, ATF4, and ATF6 seem to be dispensable for SIRT1 induction. Based on inhibitor screening experiments with SIRT1 promoter, we found that the PI3K-Akt-GSK3β signaling pathway is required for SIRT1 induction by ER stress. Moreover, we showed that pharmacological inhibition of SIRT1 by EX527 inhibited the ER stress-induced cellular death in vitro and severe hepatocellular injury in vivo, indicating a detrimental role of SIRT1 in ER stress-induced damage responses. Collectively, these data suggest that SIRT1 expression is up-regulated by ER stress and contributes to ER stress-induced cellular damage. PMID:26499802

  16. TRAM1 protects AR42J cells from caerulein-induced acute pancreatitis through ER stress-apoptosis pathway.

    PubMed

    Cai, Yongxia; Shen, Yanbo; Xu, Guangling; Tao, Ran; Yuan, Weiyan; Huang, Zhongwei; Zhang, Dongmei

    2016-05-01

    Chronic endoplasmic reticulum (ER) stress in pancreatic acinar cells has emerged as a major contributor to the recovery of acute pancreatitis (AP). However, the molecular mechanisms linking AP and ER stress remain not fully understood. In this study, we employed caerulein to induce AP-like inflammation in the AR42J rat pancreatic acinar cells to mimic the AP-like acinar cell injury. Caerulein can activate ER stress in AR42J cells, but the molecular link between AP and ER stress remains to be identified. We here reported that translocating chain-associated membrane protein 1 (TRAM1), an ER-resident multispanning membrane protein, was involved in the onset of AP-like injury on AR42J cells. TRAM1 was significantly elevated in caerulein-treated AR42J cells. Furthermore, we showed that knockdown of TRAM1 led to hyperactivation of 78 kDa glucose-regulated protein precursor (GRP78) and C/EBP homologous protein (CHOP) and the activation of downstream apoptosis pathway. Given the fact that the activation of ER stress played a protection role in AP, the pro-inflammatory mediators TNF-α and IL-6 and the marker of cell injury LDH were also analyzed. We found that depletion of TRAM1 markedly increased the secretion of TNF-α, IL-6, and LDH in the cells. Moreover, flow cytometry indicated that treatment with caerulein induced a significant decrease of apoptotic index and increase of necrosis index in TRAM1-siRNA cells, compared with control groups, as indicated by downregulated expression of cleaved caspase-3, caspase-8, and caspase-9 mRNA expression activity in TRAM1-siRNA cells. These data implicated that TRAM1 might protect AR42J cells against caerulein-induced AP in AR42J cells through alleviating ER stress.

  17. A thrombospondin-dependent pathway for a protective ER stress response

    PubMed Central

    Lynch, Jeffrey M.; Maillet, Marjorie; Vanhoutte, Davy; Schloemer, Aryn; Sargent, Michelle A.; Blair, N. Scott; Lynch, Kaari A.; Okada, Tetsuya; Aronow, Bruce J.; Osinska, Hanna; Prywes, Ron; Lorenz, John N.; Mori, Kazutoshi; Lawler, Jack; Robbins, Jeffrey; Molkentin, Jeffery D.

    2012-01-01

    SUMMARY Thrombospondin (Thbs) proteins are induced in sites of tissue damage or active remodeling. The endoplasmic reticulum (ER) stress response is also prominently induced with disease where it regulates protein production and resolution of misfolded proteins. Here we describe a novel function for Thbs’ as ER resident effectors of an adaptive ER stress response. Thbs4 cardiac-specific transgenic mice were protected from myocardial injury while Thbs4−/− mice were sensitized to cardiac maladaptation. Thbs induction produced a unique profile of adaptive ER stress response factors and expansion of the ER and downstream vesicles. The type-3 repeat domain in Thbs’ bind the ER luminal domain of activating transcription factor 6α (Atf6α) to promote its nuclear shuttling. Thbs4−/−mice failed to show activation of Atf6α and other ER stress response factors with injury, and Thbs4-mediated protection was lost when Atf6α was deleted. Hence, Thbs’ can function inside the cell during disease/remodeling to augment ER function and protect through a mechanism involving regulation of Atf6α. PMID:22682248

  18. Dietary Fish Oil Inhibits Pro-Inflammatory and ER Stress Signalling Pathways in the Liver of Sows during Lactation

    PubMed Central

    Gessner, Denise K.; Gröne, Birthe; Couturier, Aline; Rosenbaum, Susann; Hillen, Sonja; Becker, Sabrina; Erhardt, Georg; Reiner, Gerald; Ringseis, Robert; Eder, Klaus

    2015-01-01

    Lactating sows have been shown to develop typical signs of an inflammatory condition in the liver during the transition from pregnancy to lactation. Hepatic inflammation is considered critical due to the induction of an acute phase response and the activation of stress signaling pathways like the endoplasmic reticulum (ER) stress-induced unfolded protein response (UPR), both of which impair animal´s health and performance. Whether ER stress-induced UPR is also activated in the liver of lactating sows and whether dietary fish oil as a source of anti-inflammatory effects n-3 PUFA is able to attenuate hepatic inflammation and ER stress-induced UPR in the liver of sows is currently unknown. Based on this, two experiments with lactating sows were performed. The first experiment revealed that ER stress-induced UPR occurs also in the liver of sows during lactation. This was evident from the up-regulation of a set of genes regulated by the UPR and numerically increased phosphorylation of the ER stress-transducer PERK and PERK-mediated phosphorylation of eIF2α and IκB. The second experiment showed that fish oil inhibits ER stress-induced UPR in the liver of lactating sows. This was demonstrated by decreased mRNA levels of a number of UPR-regulated genes and reduced phosphorylation of PERK and PERK-mediated phosphorylation of eIF2α and IκB in the liver of the fish oil group. The mRNA levels of various nuclear factor-κB-regulated genes encoding inflammatory mediators and acute phase proteins in the liver of lactating sows were also reduced in the fish oil group. In line with this, the plasma levels of acute phase proteins were reduced in the fish oil group, although differences to the control group were not significant. In conclusion, ER stress-induced UPR is present in the liver of lactating sows and fish oil is able to inhibit inflammatory signaling pathways and ER stress-induced UPR in the liver. PMID:26351857

  19. V H+-ATPase along the yeast secretory pathway: energization of the ER and Golgi membranes.

    PubMed

    Samarão, Solange S; Teodoro, Carlos E S; Silva, Flavia E; Ribeiro, Camila C; Granato, Thais M; Bernardes, Natalia R; Retamal, Cláudio A; Façanha, Arnoldo R; Okorokova-Façanha, Anna L; Okorokov, Lev A

    2009-02-01

    H+ transport driven by V H+-ATPase was found in membrane fractions enriched with ER/PM and Golgi/Golgi-like membranes of Saccharomyces cerevisiae efficiently purified in sucrose density gradient from the vacuolar membranes according to the determination of the respective markers including vacuolar Ca2+-ATPase, Pmc1::HA. Purification of ER from PM by a removal of PM modified with concanavalin A reduced H+ transport activity of P H+-ATPase by more than 75% while that of V H+-ATPase remained unchanged. ER H+ ATPase exhibits higher resistance to bafilomycin (I50=38.4 nM) than Golgi and vacuole pumps (I50=0.18 nM). The ratio between a coupling efficiency of the pumps in ER, membranes heavier than ER, vacuoles and Golgi is 1.0, 2.1, 8.5 and 14 with the highest coupling in the Golgi. The comparative analysis of the initial velocities of H+ transport mediated by V H+-ATPases in the ER, Golgi and vacuole membrane vesicles, and immunoreactivity of the catalytic subunit A and regulatory subunit B further supported the conclusion that V H+-ATPase is the intrinsic enzyme of the yeast ER and Golgi and likely presented by distinct forms and/or selectively regulated.

  20. Spatholobus suberectus Column Extract Inhibits Estrogen Receptor Positive Breast Cancer via Suppressing ER MAPK PI3K/AKT Pathway

    PubMed Central

    Sun, Jia-Qi; Zhang, Gan-Lin; Zhang, Yi; Nan, Nan; Sun, Xu; Yu, Ming-Wei; Wang, Hong

    2016-01-01

    Although Chinese herbal compounds have long been alternatively applied for cancer treatment in China, their treatment effects have not been sufficiently investigated. The Chinese herb Spatholobus suberectus is commonly prescribed to cancer patients. HPLC analysis has shown that the main components of Spatholobus suberectus are flavonoids that can be classified as phytoestrogens, having a structure similar to estrogen. This study was designed to investigate the effects of Spatholobus suberectus column extract (SSCE) on the estrogen receptor-positive (ER+) breast cancer cell line MCF-7 and its possible molecular mechanism. In our study, MTT assay was performed to evaluate cell viability. The results show that SSCE (80, 160, and 320 μg/ml) significantly decreased the viability of MCF-7 cells. SSCE also triggered apoptosis, arrested the cell cycle at the G0/G1 phase, and inhibited cell migration. A dual-luciferase reporter system showed that SSCE suppressed intranuclear p-ER activity; Western blot analysis confirmed the repressed expression of phosphorylated-ER alpha (p-ERα), ERK1/2, p-ERK1/2, AKT, p-AKT, p-mTOR, PI3K, and p-PI3K, indicating that SSCE suppressed the MAPK PI3K/AKT signaling pathway. Collectively, our results suggest that SSCE causes apoptosis, an arrest in the G0/G1 phase, and a decrease in migration in ER+ MCF-7 cells via hypoactivity of the ER and suppression of the MAPK PI3K/AKT pathway. PMID:28096885

  1. TRAM1 protect HepG2 cells from palmitate induced insulin resistance through ER stress-JNK pathway.

    PubMed

    Tang, Zhuqi; Zhang, Wanlu; Wan, Chunhua; Xu, Guangfei; Nie, Xiaoke; Zhu, Xiaohui; Xia, Nana; Zhao, Yun; Wang, Suxin; Cui, Shiwei; Wang, Cuifang

    2015-02-20

    Excess serum free fatty acids (FFAs) are fundamental to the pathogenesis of insulin resistance. Chronic endoplasmic reticulum (ER) stress is a major contributor to obesity-induced insulin resistance in the liver. With high-fat feeding (HFD), FFAs can activate chronic endoplasmic reticulum (ER) stress in target tissues, initiating negative crosstalk between FFAs and insulin signaling. However, the molecular link between insulin resistance and ER stress remains to be identified. We here reported that translocating chain-associated membrane protein 1 (TRAM1), an ER-resident membrane protein, was involved in the onset of insulin resistance in hepatocytes. TRAM1 was significantly up-regulated in insulin-resistant liver tissues and palmitate (PA)-treated HepG2 cells. In addition, we showed that depletion of TRAM1 led to hyperactivation of CHOP and GRP78, and the activation of downstream JNK pathway. Given the fact that the activation of ER stress played a facilitating role in insulin resistance, the phosphorylation of Akt and GSK-3β was also analyzed. We found that depletion of TRAM1 markedly attenuated the phosphorylation of Akt and GSK-3β in the cells. Moreover, application with JNK inhibitor SP600125 reversed the effect of TRAM1 interference on Akt phosphorylation. The accumulation of lipid droplets and expression of two key gluconeogenic enzymes, PEPCK and G6Pase, were also determined and found to display a similar tendency with the phosphorylation of Akt. Glucose uptake assay indicated that knocking down TRAM1 augmented PA-induced down-regulation of glucose uptake, and inhibition of JNK using SP600125 could block the effect of TRAM1 on glucose uptake. These data implicated that TRAM1 might protect HepG2 cells against PA-induced insulin resistance through alleviating ER stress.

  2. Cholesterol and ORP1L-mediated ER contact sites control autophagosome transport and fusion with the endocytic pathway

    PubMed Central

    Wijdeven, Ruud H.; Janssen, Hans; Nahidiazar, Leila; Janssen, Lennert; Jalink, Kees; Berlin, Ilana; Neefjes, Jacques

    2016-01-01

    Autophagy is the main homeostatic pathway guiding cytosolic materials for degradation by the lysosome. Maturation of autophagosomes requires their transport towards the perinuclear region of the cell, with key factors underlying both processes still poorly understood. Here we show that transport and positioning of late autophagosomes depends on cholesterol by way of the cholesterol-sensing Rab7 effector ORP1L. ORP1L localizes to late autophagosomes and—under low-cholesterol conditions—contacts the ER protein VAP-A, forming ER-autophagosome contact sites, which prevent minus-end transport by the Rab7–RILP–dynein complex. ORP1L-mediated contact sites also inhibit localization of PLEKHM1 to Rab7. PLEKHM1, together with RILP, then recruits the homotypic fusion and vacuole protein-sorting (HOPS) complex for fusion of autophagosomes with late endosomes and lysosomes. Thus, ORP1L, via its liganding by lipids and the formation of contacts between autophagic vacuoles and the ER, governs the last steps in autophagy that lead to the lysosomal degradation of cytosolic material. PMID:27283760

  3. Diacylglycerol Is Required for the Formation of COPI Vesicles in the Golgi-to-ER Transport Pathway

    PubMed Central

    Fernández-Ulibarri, Inés; Vilella, Montserrat; Lázaro-Diéguez, Francisco; Sarri, Elisabet; Martínez, Susana E.; Jiménez, Nuria; Claro, Enrique; Mérida, Isabel; Burger, Koert N.J.

    2007-01-01

    Diacylglycerol is necessary for trans-Golgi network (TGN) to cell surface transport, but its functional relevance in the early secretory pathway is unclear. Although depletion of diacylglycerol did not affect ER-to-Golgi transport, it led to a redistribution of the KDEL receptor to the Golgi, indicating that Golgi-to-ER transport was perturbed. Electron microscopy revealed an accumulation of COPI-coated membrane profiles close to the Golgi cisternae. Electron tomography showed that the majority of these membrane profiles originate from coated buds, indicating a block in membrane fission. Under these conditions the Golgi-associated pool of ARFGAP1 was reduced, but there was no effect on the binding of coatomer or the membrane fission protein CtBP3/BARS to the Golgi. The addition of 1,2-dioctanoyl-sn-glycerol or the diacylglycerol analogue phorbol 12,13-dibutyrate reversed the effects of endogenous diacylglycerol depletion. Our findings implicate diacylglycerol in the retrograde transport of proteins from Golgi to the ER and suggest that it plays a critical role at a late stage of COPI vesicle formation. PMID:17567948

  4. α-Synuclein is involved in manganese-induced ER stress via PERK signal pathway in organotypic brain slice cultures.

    PubMed

    Xu, Bin; Wang, Fei; Wu, Sheng-Wen; Deng, Yu; Liu, Wei; Feng, Shu; Yang, Tian-Yao; Xu, Zhao-Fa

    2014-02-01

    Overexposure to manganese (Mn) has been known to induce neuronal damage involving endoplasmic reticulum (ER) stress. However, the exact mechanism of Mn-induced ER stress is unclear. Increasing evidence suggested that the overexpression of alpha-synuclein played a critical role in Mn-induced neurotoxicity. To explore whether the occurrence of ER stress was associated with alpha-synuclein overexpression, we made the rat brain slices model of silencing alpha-synuclein using short-interference RNA. After non-silencing alpha-synuclein slices were treated with Mn (0-400 μM) for 24 h, there was a dose-dependent increase in apoptotic rates of cells and levels of lactate dehydrogenase in the culture medium. Moreover, there was a dose-dependent increase in the protein expression of 78, 94-kDa glucose-regulated protein (GRP78/94), C/EBP homologous protein (CHOP), and caspase-12. Moreover, PKR-like ER kinase (PERK) phosphorylation, PERK-mediated phosphorylation of eIF2a, and ATF4 expression also increased. Inositol-requiring enzyme 1 (IRE1) activation and X-box-binding protein-1 (Xbp1) mRNA splicing increased. Activating transcription factor 6 p90 levels did not change. However, after silencing alpha-synuclein slices were treated with 400 μM Mn for 24 h, there was a significant decrease in the expression of GRP78/94, CHOP, and caspase-12 compared with 400 μM Mn-treated non-silencing alpha-synuclein slices. Furthermore, PERK phosphorylation, PERK-mediated phosphorylation of eIF2a, and ATF4 mRNA expression also decreased. However, IRE1 phosphorylation and Xbp1 mRNA splicing did not change. The findings revealed that Mn induced ER stress via activation of PERK and IRE1 signaling pathways and subsequent apoptosis in cultured slices. Moreover, alpha-synuclein protein was associated with Mn-induced activation of PERK signaling pathway.

  5. The PERK pathway independently triggers apoptosis and a Rac1/Slpr/JNK/Dilp8 signaling favoring tissue homeostasis in a chronic ER stress Drosophila model

    PubMed Central

    Demay, Y; Perochon, J; Szuplewski, S; Mignotte, B; Gaumer, S

    2014-01-01

    The endoplasmic reticulum (ER) has a major role in protein folding. The accumulation of unfolded proteins in the ER induces a stress, which can be resolved by the unfolded protein response (UPR). Chronicity of ER stress leads to UPR-induced apoptosis and in turn to an unbalance of tissue homeostasis. Although ER stress-dependent apoptosis is observed in a great number of devastating human diseases, how cells activate apoptosis and promote tissue homeostasis after chronic ER stress remains poorly understood. Here, using the Drosophila wing imaginal disc as a model system, we validated that Presenilin overexpression induces chronic ER stress in vivo. We observed, in this novel model of chronic ER-stress, a PERK/ATF4-dependent apoptosis requiring downregulation of the antiapoptotic diap1 gene. PERK/ATF4 also activated the JNK pathway through Rac1 and Slpr activation in apoptotic cells, leading to the expression of Dilp8. This insulin-like peptide caused a developmental delay, which partially allowed the replacement of apoptotic cells. Thanks to a novel chronic ER stress model, these results establish a new pathway that both participates in tissue homeostasis and triggers apoptosis through an original regulation. PMID:25299777

  6. Nicotinamide ameliorates palmitate-induced ER stress in hepatocytes via cAMP/PKA/CREB pathway-dependent Sirt1 upregulation.

    PubMed

    Li, Jiaxin; Dou, Xiaobing; Li, Songtao; Zhang, Ximei; Zeng, Yong; Song, Zhenyuan

    2015-11-01

    Nicotinamide (NAM) is the amide of nicotinic acid and a predominant precursor for NAD(+) biosynthesis via the salvage pathway. Sirt1 is a NAD(+)-dependent deacetylase, playing an important role in regulating cellular functions. Although hepatoprotective effect of NAM has been reported, the underlying mechanism remains elusive. ER stress, induced by saturated fatty acids, in specific palmitate, plays a pathological role in the development of nonalcoholic fatty liver disease. This study aims to determine the effect of NAM on palmitate-induced ER stress in hepatocytes and to elucidate molecular mechanisms behind. Both HepG2 cells and primary mouse hepatocytes were exposed to palmitate (conjugated to BSA at a 2:1 M ratio), NAM, or their combination for different durations. Cellular NAD(+) level, Sirt1 expression/activity, ER stress, as well as cAMP/PKA/CREB pathway activation were determined. NAM increased Sirt1 expression and enzymatic activity, which contributes to the ameliorative effect of NAM on palmitate-triggered ER stress. NAM increased intracellular NAD(+) level in hepatocytes, however, blocking the salvage pathway, a pathway for NAD(+) synthesis from NAM, only partially prevented NAM-induced Sirt1 upregulation while completely prevented NAD+ increase in response to NAM. Further mechanistic investigations revealed that NAM elevated intracellular cAMP level via suppressing PDE activity, leading to downstream PKA and CREB activation. Importantly, cAMP/PKA/CREB pathway blockade abolished not only NAM-induced Sirt1 upregulation, but also its protective effect against ER stress. Our results demonstrate that NAM protects hepatocytes against palmitate-induced ER stress in hepatocytes via upregulating Sirt1. Activation of the cAMP/PKA/CREB pathway plays a key role in NAM-induced Sirt1 upregulation.

  7. Betaine prevented fructose-induced NAFLD by regulating LXRα/PPARα pathway and alleviating ER stress in rats.

    PubMed

    Ge, Chen-Xu; Yu, Rong; Xu, Min-Xuan; Li, Pei-Qin; Fan, Chen-Yu; Li, Jian-Mei; Kong, Ling-Dong

    2016-01-05

    Betaine has been proven effective in treating nonalcoholic fatty liver disease (NAFLD) in animal models, however, its molecular mechanisms remain elusive. The aims of this study were to explore the mechanisms mediating the anti-inflammatory and anti-lipogenic actions of betaine in fructose-fed rats. In this study, betaine improved insulin resistance, reduced body weight gain and serum lipid levels, and prevented hepatic lipid accumulation in fructose-fed rats. It up-regulated hepatic expression of liver X receptor-alpha (LXRα) and peroxisome proliferator-activated receptor-alpha (PPARα), with the attenuation of the changes of their target genes, including hepatic carnitine palmitoyl transferase (CPT) 1α, glycosylphosphatidylinositol anchored high density lipoprotein binding protein 1, apolipoprotein B, sterol regulatory element-binding protein 1c and adipocyte differentiation-related protein, involved in fatty acid oxidation and lipid storage in these model rats. Furthermore, betaine alleviated ER stress and inhibited acetyl-CoA carboxylase α, CPT II, stearoyl-CoA desaturase 1 and fatty acid synthase expression involved in fatty acid synthesis in the liver of fructose-fed rats. Betaine suppressed hepatic gluconeogenesis in fructose-fed rats by moderating protein kinase B -forkhead box protein O1 pathway, as well as p38 mitogen-activated protein kinase and mammalian target of rapamycin activity. Moreover, betaine inhibited hepatic nuclear factor kappa B /nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 inflammasome activation-mediated inflammation in this animal model. These results demonstrated that betaine ameliorated hepatic lipid accumulation, gluconeogenesis, and inflammation through restoring LXRα and PPARα expression and alleviating ER stress in fructose-fed rats. This study provides the potential mechanisms of betaine involved in the treatment of NAFLD.

  8. Nickel chloride (NiCl2) induces endoplasmic reticulum (ER) stress by activating UPR pathways in the kidney of broiler chickens

    PubMed Central

    Guo, Hongrui; Cui, Hengmin; Peng, Xi; Fang, Jing; Zuo, Zhicai; Deng, Junliang; Wang, Xun; Wu, Bangyuan; Chen, Kejie; Deng, Jie

    2016-01-01

    It has been known that overexposure to Ni can induce nephrotoxicity. However, the mechanisms of underlying Ni nephrotoxicity are still elusive, and also Ni- and Ni compound-induced ER stress has been not reported in vivo at present. Our aim was to use broiler chickens as animal model to test whether the ER stress was induced and UPR was activated by NiCl2 in the kidney using histopathology, immunohistochemistry and qRT-PCR. Two hundred and eighty one-day-old broiler chickens were divided into 4 groups and fed on a control diet and the same basal diet supplemented with 300 mg/kg, 600mg/kg and 900mg/kg of NiCl2 for 42 days. We found that dietary NiCl2 in excess of 300 mg/kg induced ER stress, which was characterized by increasing protein and mRNA expression of ER stress markers, e.g., GRP78 and GRP94. Concurrently, all the three UPR pathways were activated by dietary NiCl2. Firstly, the PERK pathway was activated by increasing eIF2a and ATF4 mRNA expression. Secondly, the IRE1 pathway was activated duo to increase in IRE1 and XBP1 mRNA expression. And thirdly, the increase of ATF6 mRNA expression suggested that ATF6 pathway was activated. The findings clearly demonstrate that NiCl2 induces the ER stress through activating PERK, IRE1 and ATF6 UPR pathways, which is proved to be a kind of molecular mechanism of Ni- or/and Ni compound-induced nephrotoxicity. PMID:26956054

  9. Quercetin alleviates cell apoptosis and inflammation via the ER stress pathway in vascular endothelial cells cultured in high concentrations of glucosamine.

    PubMed

    Cai, Xiaxia; Bao, Lei; Ding, Ye; Dai, Xiaoqian; Zhang, Zhaofeng; Li, Yong

    2017-02-01

    Glucosamine is a possible cause of vascular endothelial injury in the initial stages of atherosclerosis, through endoplasmic reticulum (ER) stress resulting in fatty streaks in the vascular wall. Quercetin is an anti‑diabetic and cardiovascular protective agent that has previously been demonstrated to reduce ER stress in human umbilical vein endothelial cells (HUVECs). The present study aimed to investigate whether quercetin prevents glucosamine‑induced apoptosis and inflammation via ER stress pathway in HUVECs. The effect of quercetin on cell viability, apoptosis, and protein expression levels of inflammatory cytokines and ER stress markers was investigated in glucosamine‑supplemented HUVECs. Quercetin was demonstrated to protect against glucosamine‑induced apoptosis, improved cell viability, and inhibited expression of pro‑inflammatory factors and endothelin‑1. Quercetin treatment also reduced the expression levels of glucose‑regulated protein 78, phosphorylated protein kinase‑like ER kinase, phosphorylated c‑Jun N‑terminal kinase and C/EBP homologous protein. In conclusion, quercetin may have auxiliary therapeutic potential against glucosamine‑induced cell apoptosis and inflammation, which may be partially due to alleviation of ER stress.

  10. Molecular pathway of near-infrared laser phototoxicity involves ATF-4 orchestrated ER stress

    PubMed Central

    Khan, Imran; Tang, Elieza; Arany, Praveen

    2015-01-01

    High power lasers are used extensively in medicine while lower power applications are popular for optical imaging, optogenetics, skin rejuvenation and a therapeutic modality termed photobiomodulation (PBM). This study addresses the therapeutic dose limits, biological safety and molecular pathway of near-infrared (NIR) laser phototoxicity. Increased erythema and tissue damage were noted in mice skin and cytotoxicity in cell cultures at phototoxic laser doses involving generation of reactive oxygen species (ROS) coupled with a rise in surface temperature (>45 °C). NIR laser phototoxicity results from Activating Transcription Factor-4 (ATF-4) mediated endoplasmic reticulum stress and autophagy. Neutralizations of heat or ROS and overexpressing ATF-4 were noted to rescue NIR laser phototoxicity. Further, NIR laser mediated phototoxicity was noted to be non-genotoxic and non-mutagenic. This study outlines the mechanism of NIR laser phototoxicity and the utility of monitoring surface temperature and ATF4 expression as potential biomarkers to develop safe and effective clinical applications. PMID:26030745

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

    PubMed

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

    2015-03-01

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

  12. Glycycoumarin inhibits hepatocyte lipoapoptosis through activation of autophagy and inhibition of ER stress/GSK-3-mediated mitochondrial pathway

    PubMed Central

    Zhang, Enxiang; Yin, Shutao; Song, Xinhua; Fan, Lihong; Hu, Hongbo

    2016-01-01

    Herbal medicine as an alternative approach in the treatment of disease has drawn growing attention. Identification of the active ingredient is needed for effective utilization of the herbal medicine. Licorice is a popular herbal plant that is widely used to treat various diseases including liver diseases. Glycycoumarin (GCM) is a representative of courmarin compounds isolated from licorice. In the present study, the protective effect of GCM on hepatocyte lipoapoptosis has been evaluated using both cell culture model of palmitate-induced lipoapoptosis and animal model of non-alcoholic steatohepatitis (NASH). The results demonstrated for the first time that GCM was highly effective in suppressing hepatocyte lipoapoptosis in both in vitro and in vivo. Mechanistically, GCM was able to re-activate the impaired autophagy by lipid metabolic disorders. In line with the activation of autophagy, ER stress-mediated JNK and mitochondrial apoptotic pathway activation was inhibited by GCM both in vitro and in vivo. In addition, inactivation of GSK-3 might also contribute to the protective effect of GCM on hepatocyte lipoapoptosis. Our findings supported GCM as a novel active component of licorice against non-alcoholic fatty liver disease (NAFLD). PMID:27901086

  13. Spectral evidence for multi-pathway contribution to the upconversion pathway in NaYF4:Yb(3+),Er(3+) phosphors.

    PubMed

    Cho, Youngho; Song, Si Won; Lim, Soo Yeong; Kim, Jae Hun; Park, Chan Ryang; Kim, Hyung Min

    2017-03-08

    Although upconversion phosphors have been widely used in nanomedicine, laser engineering, bioimaging, and solar cell technology, the upconversion luminescence mechanism of the phosphors has been fiercely debated. A comprehensive understanding of upconversion photophysics has been significantly impeded because the number of photons incorporated in the process in different competitive pathways could not be resolved. Few convincing results to estimate the contribution of each of the two-, three-, and four-photon channels of near-infrared (NIR) energy have been reported in yielding upconverted visible luminescence. In this study, we present the energy upconversion process occurring in NaYF4:Yb(3+),Er(3+) phosphors as a function of excitation frequency and power density. We investigated the upconversion mechanism of lanthanide phosphors by comparing UV/VIS one-photon excitation spectra and NIR multi-photon spectra. A detailed analysis of minor transitions in one-photon spectra and luminescence decay enables us to assign electronic origins of individual bands in multi-photon upconversion luminescence and provides characteristic transitions representing the corresponding upconversion channel. Furthermore, we estimated the quantitative contribution of multiple channels with respect to irradiation power and excitation energy.

  14. ApoER2 and VLDLr Are Required for Mediating Reelin Signalling Pathway for Normal Migration and Positioning of Mesencephalic Dopaminergic Neurons

    PubMed Central

    Sharaf, Ahmed; Bock, Hans H.; Spittau, Björn; Bouché, Elisabeth; Krieglstein, Kerstin

    2013-01-01

    The migration of mesencephalic dopaminergic (mDA) neurons from the subventricular zone to their final positions in the substantia nigra compacta (SNc), ventral tegmental area (VTA), and retrorubral field (RRF) is controlled by signalling from neurotrophic factors, cell adhesion molecules (CAMs) and extracellular matrix molecules (ECM). Reelin and the cytoplasmic adaptor protein Disabled-1 (Dab1) have been shown to play important roles in the migration and positioning of mDA neurons. Mice lacking Reelin and Dab1 both display phenotypes characterised by the failure of nigral mDA neurons to migrate properly. ApoER2 and VLDLr are receptors for Reelin signalling and are therefore part of the same signal transduction pathway as Dab1. Here we describe the roles of ApoER2 and VLDLr in the proper migration and positioning of mDA neurons in mice. Our results demonstrate that VLDLr- and ApoER2-mutant mice have both a reduction in and abnormal positioning of mDA neurons. This phenotype was more pronounced in VLDLr-mutant mice. Moreover, we provide evidence that ApoER2/VLDLr double-knockout mice show a phenotype comparable with the phenotypes observed for Reelin- and Dab1- mutant mice. Taken together, our results demonstrate that the Reelin receptors ApoER2 and VLDLr play essential roles in Reelin-mediated migration and positioning of mDA neurons. PMID:23976984

  15. Effects of 4-nitrophenol on expression of the ER-α and AhR signaling pathway-associated genes in the small intestine of rats.

    PubMed

    Tang, Juan; Song, Meiyan; Watanabe, Gen; Nagaoka, Kentaro; Rui, Xiaoli; Li, ChunMei

    2016-09-01

    4-Nitrophenol (PNP) is a persistent organic pollutant that was proven to be an environmental endocrine disruptor. The aim of this study was to evaluate the role of the estrogen receptor-α (ER-α) and aryl hydrocarbon receptor (AhR) signaling pathway in regulating the damage response to PNP in the small intestine of rats. Wistar-Imamichi male rats (21 d) were randomly divided into two groups: the control group and PNP group. Each group had three processes that were gavaged with PNP or vehicle daily: single dose (1 d), repeated dose (3 consecutive days) (3 d), and repeated dose with recovery (3 consecutive days and 3 recovery days) (6 d). The weight of the body, the related viscera, and small intestine were examined. Histological parameters of the small intestine and the quantity of mucus proteins secreted by small goblet cells were determined using HE staining and PAS staining. The mRNA expression of AhR, ER-α, CYP1A1, and GST was measured by real-time qPCR. In addition, we also analyzed the AhR, ER-α, and CYP1A1 expression in the small intestine by immunohistochemical staining. The small intestines histologically changed in the PNP-treated rat and the expression of AhR, CYP1A1, and GST was increased. While ER-α was significantly decreased in the small intestine, simultaneously, when rats were exposed to a longer PNP treatment, the damages disappeared. Our results demonstrate that PNP has an effect on the expression of AhR signaling pathway genes, AhR, CYP1A1, and GST, and ER-α in the rat small intestine.

  16. Resolvin D1 reduces ER stress-induced apoptosis and triglyceride accumulation through JNK pathway in HepG2 cells.

    PubMed

    Jung, Tae Woo; Hwang, Hwan-Jin; Hong, Ho Cheol; Choi, Hae Yoon; Yoo, Hye Jin; Baik, Sei Hyun; Choi, Kyung Mook

    2014-06-25

    Research has indicated that stress on the endoplasmic reticulum (ER) of a cell affects the pathogenesis of metabolic disorders such as obesity, type 2 diabetes mellitus, and non-alcoholic fatty liver disease (NAFLD). Resolvins, a novel family derived from ω-3 polyunsaturated fatty acids, have anti-inflammatory and insulin sensitizing properties, and it has been suggested that they play a role in the amelioration of obesity-related metabolic dysfunctions. This study showed that pretreatment with resolvin D1 (RvD1) attenuated ER stress-induced apoptosis and also decreased caspase 3 activity in HepG2 cells. Furthermore, RvD1 significantly decreased tunicamycin-induced triglycerides accumulation as well as SREBP-1 expression. However, tunicamycin-induced ER stress markers were not significantly affected by RvD1 treatment. Moreover, RvD1 treatment did not affect the tunicamycin-induced expression of chaperones that assist protein folding in the ER. These results suggest that RvD1-conferred cellular protection may occur downstream of the ER stress. This was supported by the finding that RvD1 significantly inhibited tunicamycin-induced c-Jun N-terminal kinase (JNK) expression, although P38 and ERK1/2 phosphorylation were not affected. In addition, anisomycin, a JNK activator, increased caspase 3 activity and apoptosis as well as triglycerides accumulation and SREBP1 expression, and RvD1 treatment reversed these changes. In conclusion, RvD1 attenuated ER stress-induced hepatic steatosis and apoptosis via the JNK-mediated pathway. This study may provide insight into a novel underlying mechanism and a strategy for treating NAFLD.

  17. The response of trypanosomes and other eukaryotes to ER stress and the spliced leader RNA silencing (SLS) pathway in Trypanosoma brucei.

    PubMed

    Michaeli, Shulamit

    2015-01-01

    The unfolded protein response (UPR) is induced when the quality control machinery of the cell is overloaded with unfolded proteins or when one of the functions of the endoplasmic reticulum (ER) is perturbed. Here, I describe UPR in yeast and mammals, and compare it to what we know about pathogenic fungi and the parasitic protozoans from the order kinetoplastida, focusing on the novel pathway the spliced leader silencing (SLS) in Trypanosoma brucei. Trypanosomes lack conventional transcription regulation, and thus, lack most of the UPR machinery present in other eukaryotes. Trypanosome genes are transcribed in polycistronic units that are processed by trans-splicing and polyadenylation. In trans-splicing, which is essential for processing of each mRNA, an exon known as the spliced leader (SL) is added to all mRNAs from a small RNA, the SL RNA. Under severe ER stress, T. brucei elicits the SLS pathway. In SLS, the transcription of the SL RNA gene is extinguished, and the entire transcription complex dissociates from the SL RNA promoter. Induction of SLS is mediated by an ER-associated kinase (PK3) that migrates to the nucleus, where it phosphorylates the TATA-binding protein (TRF4), leading shut-off of SL RNA transcription. As a result, trans-splicing is inhibited and the parasites activate a programmed cell death (PCD) pathway. Despite the ability to sense the ER stress, the different eukaryotes, especially unicellular parasites and pathogenic fungi, developed a variety of unique and different ways to sense and adjust to this stress in a manner different from their host.

  18. An uncleaved signal peptide directs the Malus xiaojinensis iron transporter protein Mx IRT1 into the ER for the PM secretory pathway.

    PubMed

    Zhang, Peng; Tan, Song; Berry, James O; Li, Peng; Ren, Na; Li, Shuang; Yang, Guang; Wang, Wei-Bing; Qi, Xiao-Ting; Yin, Li-Ping

    2014-11-07

    Malus xiaojinensis iron-regulated transporter 1 (Mx IRT1) is a highly effective inducible iron transporter in the iron efficient plant Malus xiaojinensis. As a multi-pass integral plasma membrane (PM) protein, Mx IRT1 is predicted to consist of eight transmembrane domains, with a putative N-terminal signal peptide (SP) of 1-29 amino acids. To explore the role of the putative SP, constructs expressing Mx IRT1 (with an intact SP) and Mx DsIRT1 (with a deleted SP) were prepared for expression in Arabidopsis and in yeast. Mx IRT1 could rescue the iron-deficiency phenotype of an Arabidopsis irt1 mutant, and complement the iron-limited growth defect of the yeast mutant DEY 1453 (fet3fet4). Furthermore, fluorescence analysis indicated that a chimeric Mx IRT1-eGFP (enhanced Green Fluorescent Protein) construct was translocated into the ER (Endoplasmic reticulum) for the PM sorting pathway. In contrast, the SP-deleted Mx DsIRT1 could not rescue either of the mutant phenotypes, nor direct transport of the GFP signal into the ER. Interestingly, immunoblot analysis indicated that the SP was not cleaved from the mature protein following transport into the ER. Taken together, data presented here provides strong evidence that an uncleaved SP determines ER-targeting of Mx IRT1 during the initial sorting stage, thereby enabling the subsequent transport and integration of this protein into the PM for its crucial role in iron uptake.

  19. An Uncleaved Signal Peptide Directs the Malus xiaojinensis Iron Transporter Protein Mx IRT1 into the ER for the PM Secretory Pathway

    PubMed Central

    Zhang, Peng; Tan, Song; Berry, James O.; Li, Peng; Ren, Na; Li, Shuang; Yang, Guang; Wang, Wei-Bing; Qi, Xiao-Ting; Yin, Li-Ping

    2014-01-01

    Malus xiaojinensis iron-regulated transporter 1 (Mx IRT1) is a highly effective inducible iron transporter in the iron efficient plant Malus xiaojinensis. As a multi-pass integral plasma membrane (PM) protein, Mx IRT1 is predicted to consist of eight transmembrane domains, with a putative N-terminal signal peptide (SP) of 1–29 amino acids. To explore the role of the putative SP, constructs expressing Mx IRT1 (with an intact SP) and Mx DsIRT1 (with a deleted SP) were prepared for expression in Arabidopsis and in yeast. Mx IRT1 could rescue the iron-deficiency phenotype of an Arabidopsis irt1 mutant, and complement the iron-limited growth defect of the yeast mutant DEY 1453 (fet3fet4). Furthermore, fluorescence analysis indicated that a chimeric Mx IRT1-eGFP (enhanced Green Fluorescent Protein) construct was translocated into the ER (Endoplasmic reticulum) for the PM sorting pathway. In contrast, the SP-deleted Mx DsIRT1 could not rescue either of the mutant phenotypes, nor direct transport of the GFP signal into the ER. Interestingly, immunoblot analysis indicated that the SP was not cleaved from the mature protein following transport into the ER. Taken together, data presented here provides strong evidence that an uncleaved SP determines ER-targeting of Mx IRT1 during the initial sorting stage, thereby enabling the subsequent transport and integration of this protein into the PM for its crucial role in iron uptake. PMID:25387073

  20. Wolfberry Water Soluble Phytochemicals Down-Regulate ER Stress Biomarkers and Modulate Multiple Signaling Pathways Leading To Inhibition of Proliferation and Induction of Apoptosis in Jurkat Cells

    PubMed Central

    Jiang, Yu; Zhang, Yunong; Wark, Logan; Ortiz, Edlin; Lim, Soyoung; He, Hui; Wang, Weiqun; Medeiros, Denis; Lin, Dingbo

    2012-01-01

    Phytochemicals have received much recent attention in cancer prevention through simultaneous targeting multiple pathways in the disease progression. Here we determined that wolfberry phytochemicals was chemopreventive on the leukemic Jurkat cell. The water soluble wolfberry fractions (i.e., wolfberry phytochemicals) were enriched in carbohydrates (73.4 ± 4.5 % (w/w)), polyphenolics (1555 ± 112 mg quercetin equivalent/100 g freeze dry powder, including 213 mg rutin/100 g freeze dry powder), and had enhanced antioxidant activity (7771 ± 207 μM Trolox equivalent/100 g freeze dry powder). Wolfberry phytochemicals, but not purified wolfberry polysaccharide fractions, inhibited Jurkat cell proliferation, induced cycle arrest at the G2/M phase in a dose dependent manner starting at 1 mg/ml for 48 h. Wolfberry phytochemicals eliminated cellular reactive oxygen species, declined expression of endoplasmic reticulum (ER) stress biomarkers, including glucose regulated protein 78, inositol-requiring protein 1(IRE1), activating transcription factor 6 (ATF6), protein kinase RNA-like ER kinase (PERK), and c/EBP-homologous protein, and induced activation of AMP activated protein kinase, stabilization of β-catenin, and inhibition of NFκB, and AKT activity. Simultaneous siRNA knockdown of ATF6, IRE1 and PERK caused inhibition of cell proliferation and induction of apoptosis. Data suggested that ER stress and multiple survival/apoptosis signaling pathways were modulated by wolfberry phytochemicals during the apoptotic progression. Consumption of wolfberry could be an efficacious dietary strategy for preventing leukemia. PMID:22685690

  1. Antiapoptotic roles of ceramide-synthase-6-generated C16-ceramide via selective regulation of the ATF6/CHOP arm of ER-stress-response pathways.

    PubMed

    Senkal, Can E; Ponnusamy, Suriyan; Bielawski, Jacek; Hannun, Yusuf A; Ogretmen, Besim

    2010-01-01

    Emerging results suggest that ceramides with different fatty acid chain lengths might play distinct functions in the regulation of tumor growth and therapy. Here we report that de novo-generated C(18)- and C(16)-ceramides by ceramide synthases 1 and 6 (CerS1 and CerS6) play opposing proapoptotic and prosurvival roles, respectively, in human head and neck squamous cell carcinomas (HNSCCs). Unexpectedly, knockdown of CerS6/C(16)-ceramide using small interfering RNA induced endoplasmic reticulum (ER)-stress-mediated apoptosis. Reconstitution of C(16)-ceramide generation by induced expression of wild-type CerS6, but not its catalytically inactive mutant, protected cells from cell death induced by knockdown of CerS6. Moreover, using molecular tools coupled with analysis of sphingolipid metabolism showed that generation of C(16)-ceramide, and not dihydro-C(16)-ceramide, by induced expression of CerS6 rescued cells from ER stress and apoptosis. Mechanistically, regulation of ER-stress-induced apoptosis by CerS6/C(16)-ceramide was linked to the activation of a specific arm, ATF6/CHOP, of the unfolded protein response pathway. Notably, while expression of CerS1/C(18)-ceramide inhibited HNSCC xenograft growth, CerS6/C(16)-ceramide significantly protected ER stress, leading to enhanced tumor development and growth in vivo, consistent with their pro- and antiapoptotic roles, respectively. Thus, these data reveal an unexpected and novel prosurvival role of CerS6/C(16)-ceramide involved in the protection against ER-stress-induced apoptosis and induction of HNSCC tumor growth.

  2. Apoptosis-linked gene-2 (ALG-2)/Sec31 interactions regulate endoplasmic reticulum (ER)-to-Golgi transport: a potential effector pathway for luminal calcium.

    PubMed

    Helm, Jared R; Bentley, Marvin; Thorsen, Kevin D; Wang, Ting; Foltz, Lauren; Oorschot, Viola; Klumperman, Judith; Hay, Jesse C

    2014-08-22

    Luminal calcium released from secretory organelles has been suggested to play a regulatory role in vesicle transport at several steps in the secretory pathway; however, its functional roles and effector pathways have not been elucidated. Here we demonstrate for the first time that specific luminal calcium depletion leads to a significant decrease in endoplasmic reticulum (ER)-to-Golgi transport rates in intact cells. Ultrastructural analysis revealed that luminal calcium depletion is accompanied by increased accumulation of intermediate compartment proteins in COPII buds and clusters of unfused COPII vesicles at ER exit sites. Furthermore, we present several lines of evidence suggesting that luminal calcium affected transport at least in part through calcium-dependent interactions between apoptosis-linked gene-2 (ALG-2) and the Sec31A proline-rich region: 1) targeted disruption of ALG-2/Sec31A interactions caused severe defects in ER-to-Golgi transport in intact cells; 2) effects of luminal calcium and ALG-2/Sec31A interactions on transport mutually required each other; and 3) Sec31A function in transport required luminal calcium. Morphological phenotypes of disrupted ALG-2/Sec31A interactions were characterized. We found that ALG-2/Sec31A interactions were not required for the localization of Sec31A to ER exit sites per se but appeared to acutely regulate the stability and trafficking of the cargo receptor p24 and the distribution of the vesicle tether protein p115. These results represent the first outline of a mechanism that connects luminal calcium to specific protein interactions regulating vesicle trafficking machinery.

  3. Induction of ER stress in response to oxygen-glucose deprivation of cortical cultures involves the activation of the PERK and IRE-1 pathways and of caspase-12

    PubMed Central

    Badiola, N; Penas, C; Miñano-Molina, A; Barneda-Zahonero, B; Fadó, R; Sánchez-Opazo, G; Comella, J X; Sabriá, J; Zhu, C; Blomgren, K; Casas, C; Rodríguez-Alvarez, J

    2011-01-01

    Disturbance of calcium homeostasis and accumulation of misfolded proteins in the endoplasmic reticulum (ER) are considered contributory components of cell death after ischemia. However, the signal-transducing events that are activated by ER stress after cerebral ischemia are incompletely understood. In this study, we show that caspase-12 and the PERK and IRE pathways are activated following oxygen-glucose deprivation (OGD) of mixed cortical cultures or neonatal hypoxia–ischemia (HI). Activation of PERK led to a transient phosphorylation of eIF2α, an increase in ATF4 levels and the induction of gadd34 (a subunit of an eIF2α-directed phosphatase). Interestingly, the upregulation of ATF4 did not lead to an increase in the levels of CHOP. Additionally, IRE1 activation was mediated by the increase in the processed form of xbp1, which would be responsible for the observed expression of edem2 and the increased levels of the chaperones GRP78 and GRP94. We were also able to detect caspase-12 proteolysis after HI or OGD. Processing of procaspase-12 was mediated by NMDA receptor and calpain activation. Moreover, our data suggest that caspase-12 activation is independent of the unfolded protein response activated by ER stress. PMID:21525936

  4. ATG14 facilitated lipophagy in cancer cells induce ER stress mediated mitoptosis through a ROS dependent pathway.

    PubMed

    Mukhopadhyay, Subhadip; Schlaepfer, Isabel R; Bergman, Bryan C; Panda, Prashanta Kumar; Praharaj, Prakash Priyadarshi; Naik, Prajna Paramita; Agarwal, Rajesh; Bhutia, Sujit Kumar

    2017-03-01

    Understanding the dynamics of autophagy and apoptosis crosstalk in cancer progression remains a challenging task. Here, we reported how the autophagy protein ATG14 induces lipophagy-mediated mitochondrial apoptosis. The overexpression of ATG14 in HeLa cells inhibited cell viability and increased mitochondrial apoptosis and endoplasmic reticulum (ER) stress. Furthermore, inhibition of this ATG14-induced autophagy promoted apoptosis. ATG14 overexpression resulted in the accumulation of free fatty acids (FFA), with a concomitant decrease in the number of lipid droplets. Our data showed that ER stress induced by ATG14 was due to the lipophagy-mediated FFA accumulation, which resulted in ROS-dependent mitochondrial stress leading to apoptosis. Inhibition of lipophagy in HeLa-ATG14 cells enhanced the cellular viability and rescued them from lipotoxicity. Mechanistically, we found that ATG14 interacted with Ulk1 and LC3, and knock down of Ulk1 prevented the lipidation of LC3 and autophagy in HeLa-ATG14 cells. We also identified a phosphatidylethanolamine (PE) binding region in ATG14, and the addition of Ulk1 to Hela-ATG14 cells decreased the ATG14-PE interaction. Lastly, confocal microscopy studies showed that the decrease in ATG14-PE binding was concomitant with the increase in LC3 lipidation over time, confirming the importance of Ulk1 to sort PE to LC3 during ATG14 mediated lipophagy induction. In conclusion, ATG14 and Ulk1 interact to induce lipophagy resulting in FFA accumulation leading to ER stress-mediated apoptosis.

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

    PubMed

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

    2015-08-27

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

  6. Paeoniflorin protects cells from GalN/TNF-α-induced apoptosis via ER stress and mitochondria-dependent pathways in human L02 hepatocytes.

    PubMed

    Jiang, Zequn; Chen, Weiping; Yan, Xiaojing; Bi, Lei; Guo, Sheng; Zhan, Zhen

    2014-05-01

    Paeoniflorin (PF) is one of the main effective components extracted from the root of Paeonia lactiflora, which has been used clinically to treat hepatitis in traditional Chinese medicine, but the details of the underlying mechanism remain unknown. The present study was designed to investigate the mechanism of protective effect of PF on d-galactosamine (GalN) and tumor necrosis factor-α (TNF-α)-induced cell apoptosis using human L02 hepatocytes. Our results confirmed that PF could attenuate GalN/TNF-α-induced apoptotic cell death in a dose-dependent manner. The disruption of mitochondrial membrane potential and the disturbance of intracellular Ca(2+) concentration were also recovered by PF. Western blot analysis revealed that GalN/TNF-α induced the activation of a number of signature endoplasmic reticulum (ER) stress and mitochondrial markers, while PF pre-treatment had a marked dose-dependent suppression on them. Additionally, the anti-apoptotic effect of PF was further evidenced by the inhibition of caspase-3/9 activities in L02 cells. These findings suggest that PF can effectively inhibit hepatocyte apoptosis and the underlying mechanism is related to the regulating mediators in ER stress and mitochondria-dependent pathways.

  7. ROS generation mediates the anti-cancer effects of WZ35 via activating JNK and ER stress apoptotic pathways in gastric cancer

    PubMed Central

    Zou, Peng; Zhang, Junru; Xia, Yiqun; Kanchana, Karvannan; Guo, Guilong; Chen, Wenbo; Huang, Yi; Wang, Zhe; Yang, Shulin; Liang, Guang

    2015-01-01

    Gastric cancer is one of the leading causes of cancer mortality in the world, and finding novel agents and strategies for the treatment of advanced gastric cancer is of urgent need. Curcumin is a well-known natural product with anti-cancer ability, but is limited by its poor chemical stability. In this study, an analog of curcumin with high chemical stability, WZ35, was designed and evaluated for its anti-cancer effects and underlying mechanisms against human gastric cancer. WZ35 showed much stronger anti-proliferative effects than curcumin, accompanied by dose-dependent induction of cell cycle arrest and apoptosis in gastric cancer cells. Mechanistically, our data showed that WZ35 induced reactive oxygen species (ROS) production, resulting in the activation of both JNK-mitochondrial and ER stress apoptotic pathways and eventually cell apoptosis in SGC-7901 cells. Blockage of ROS production totally reversed WZ35-induced JNK and ER stress activation as well as cancer cell apoptosis. In vivo, WZ35 showed a significant reduction in SGC-7901 xenograft tumor size in a dose-dependent manner. Taken together, this work provides a novel anticancer candidate for the treatment of gastric cancer, and importantly, reveals that increased ROS generation might be an effective strategy in human gastric cancer treatment. PMID:25714022

  8. Carbon monoxide offers neuroprotection from hippocampal cell damage induced by recurrent febrile seizures through the PERK-activated ER stress pathway.

    PubMed

    Han, Ying; Yi, Wenxia; Qin, Jiong; Zhao, Yang; Zhang, Jing; Chang, Xingzhi

    2015-01-12

    Carbon monoxide (CO) is neuroprotective in various models of brain injury, but the precise mechanisms for this are yet to be established. In the present study, using a rat model of recurrent febrile seizures (FSs), we found an increase in plasma CO, evidence of neuronal damage and apoptosis, an increase in the expression of the endoplasmic reticulum stress (ERS) marker glucose-regulated protein 78 (GRP78) and C/EBP homologous binding protein (CHOP), and an increase in phosphorylated protein kinase RNA-like endoplasmic reticulum kinase (p-PERK)/eukaryotic translation initiation factor 2 alpha (p-eIF2α) in the hippocampus after 10 FSs. Administration of Hemin (a CO donor) in FS rats alleviated the neuronal damage, reduced neuronal apoptosis, upregulated GRP78 expression, decreased CHOP, and increased p-PERK and p-eIF2α expression in the hippocampus, compared to FS control rats. In contrast, treating FS rats with ZnPP-IX (a CO synthase inhibitor) aggravated the neuronal damage, enhanced neuronal apoptosis, downregulated GRP78 expression, increased CHOP, and decreased p-PERK and p-eIF2α expression, compared to FS control rats. These results suggest that endogenous CO limits the neuronal damage induced by recurrent FSs, through the PERK-activated ERS pathway.

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

    PubMed Central

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

    2016-01-01

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

  10. Role of the ER/NO/cGMP Signaling Pathway in the Promotion of Osteogenic Differentiation of Rat Bone Marrow Mesenchymal Stem Cells by Actaea racemosa Extract

    PubMed Central

    Yang, Shenlan; Zhou, Yanping; Zhu, Rui; Xu, Wei; Wu, Yanran; Deng, Danfang; Luo, Yingying

    2016-01-01

    Purpose/Objective. To investigate the effect of Actaea racemosa (AR) extract on in vitro osteogenic differentiation of rat bone marrow mesenchymal stem cells (BMSCs) via the ER/NO/cGMP signaling pathway. Methods/Materials. Rat BMSCs were treated with osteogenic differentiation-inducing medium containing AR; estrogen receptor antagonist, ICI 182,780 (10−6 mol/L); and nitric oxide synthase inhibitor, L-nitro arginine methyl ester (L-NAME, 6 × 10−3 mol/L). Markers of osteogenic differentiation (alkaline phosphatase [ALP] activity, osteocalcin secretion, and calcium ion deposit levels) and the levels of key signaling molecules (nitric oxide synthase [NOS], nitric oxide [NO], and cyclic guanosine monophosphate [cGMP]) were assessed. Results. AR (10−1–10−6 g/L) increased ALP activity in a dose-dependent manner, and the highest ALP, osteocalcin, and osteoprotegerin activities were achieved at an AR concentration of 10−4 g/L. Therefore, the concentration of 10−4 g/L was used for promoting osteogenic differentiation of BMSCs in subsequent analyses. At this concentration, AR increased the levels of NO and cGMP, and such effects could be blocked by the estrogen receptor antagonist (ICI 182,780) and nitric oxide synthase inhibitor (L-NAME). Conclusion. AR induced osteogenic differentiation of rat BMSCs through the ER/NO/cGMP signaling pathway. This finding provides the theoretical foundation for the mechanism of AR in the treatment of postmenopausal osteoporosis. PMID:27974901

  11. Hepatitis B Virus Middle Protein Enhances IL-6 Production via p38 MAPK/NF-κB Pathways in an ER Stress-Dependent Manner

    PubMed Central

    Li, Yang-Xia; Ren, Yan-Li; Fu, Hai-Jing; Zou, Ling; Yang, Ying; Chen, Zhi

    2016-01-01

    During hepatitis B virus (HBV) infection, three viral envelope proteins of HBV are overexpressed in the endoplasmic reticulum (ER). The large S protein (LHBs) and truncated middle S protein (MHBst) have been documented to play roles in regulating host gene expression and contribute to hepatic disease development. As a predominant protein at the ultrastructural level in biopsy samples taken from viremic patients, the role of the middle S protein (MHBs) remains to be understood despite its high immunogenicity. When we transfected hepatocytes with an enhanced green fluorescent protein (EGFP)-tagged MHBs expressing plasmid, the results showed that expression of MHBs cause an upregulation of IL-6 at the message RNA and protein levels through activating the p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor-kappa B (NF-κB) pathways. The use of specific inhibitors of the signaling pathways can diminish this upregulation. The use of BAPTA-AM attenuated the stimulation caused by MHBs. We further found that MHBs accumulated in the endoplasmic reticulum and increased the amount of glucose regulated protein 78 (GRP78/BiP). Our results provide a possibility that MHBs could be involved in liver disease progression. PMID:27434097

  12. Effects of Er-Zhi-Wan on microarchitecture and regulation of Wnt/β-catenin signaling pathway in alveolar bone of ovariectomized rats.

    PubMed

    Sun, Wei; Wang, Yuan-qin; Yan, Qi; Lu, Rui; Shi, Bin

    2014-02-01

    Recent studies have shown that Er-Zhi-Wan (EZW), a traditional Chinese medicine consisting of Herba Ecliptae (HE) and Fructus Ligustri Lucidi (FLL), had a definite antiosteoporotic effect on osteoporotic femur, but its effect on osteoporosis of alveolar bone remains unknown. In the present study, we investigated the effects of Er-Zhi-Wan (EZW) on the microarchitecture and the regulation of Wnt/β-catenin signaling pathway in the alveolar bone of ovariectomized rats. Thirty Sprague-Dawley rats were randomly divided into three groups: sham operation group (sham, n=10), ovariectomy (OVX) group (n=10), and OVX with EZW treatment group (EZW group, n=10). From one week after ovariectomy, EZW (100 mg/mL) or vehicle (distilled water) was fed (1 mL/100 g) once per day for 12 weeks until the sacrifice of the rats. The body weights were measured weekly. After sacrifice, the sera and mandible were collected and routinely prepared for the measurement of alveolar trabecular microarchitecture, serum levels of E2, bone-specific alkaline phosphatase (BALP) and tartrate-resistant acid phosphatase 5b (TRAP5b), as well as mandibular mRNA expression of Wnt/β-catenin signaling pathway molecules wnt3a, low-density lipoprotein receptor-related protein 5 (LRP5), β-catenin and dickkopf homolog 1 (DKK1). The results showed that EZW treatment significantly prevented the body weight gain, degradation of alveolar trabecular microarchitecture and alveolar bone loss in the OVX rats. Furthermore, we observed that EZW could increase the serum levels of E2 and BALP, and decrease levels of serum TRAP5b in EZW group compared with vehicle group. In addition, RT-PCR results revealed that EZW upregulated the expression levels of wnt3a, LRP5 and β-catenin, and reduced the expression of DKK1 in OVX rats. Taken together, our results suggested that EZW may have potential anti-osteoporotic effects on osteoporotic alveolar bone by stimulating Wnt/LRP5/β-catenin signaling pathway.

  13. CHOP-independent apoptosis and pathway-selective induction of the UPR in developing plasma cells

    PubMed Central

    Masciarelli, Silvia; Fra, Anna M.; Pengo, Niccoló; Bertolotti, Milena; Cenci, Simone; Fagioli, Claudio; Ron, David; Hendershot, Linda M; Sitia, Roberto

    2010-01-01

    Upon antigen stimulation, B lymphocytes differentiate into antibody secreting cells (ASC), most of which undergo apoptosis after a few days of intense Ig production. Differentiation entails expansion of the endoplasmic reticulum (ER) and requires XBP1 but not other elements of the unfolded protein response, like Perk. Moreover, normal and malignant ASC are exquisitely sensitive to proteasome inhibitors, but the underlying mechanisms are poorly understood. Here we analyze the role of CHOP, a transcription factor mediating apoptosis in many cell types that experience high levels of ER stress. CHOP is transiently induced early upon B cell stimulation: covalent IgM aggregates form more readily and IgM secretion is slower in chop-/- cells. Despite these subtle changes, ASC differentiation and lifespan are normal in chop-/- mice. Unlike fibroblasts and other cell types, chop-/- ASC are equally or slightly more sensitive to proteasome inhibitors and ER stressors, implying tissue-specific roles for CHOP in differentiation and stress. PMID:20044139

  14. Molybdenum induces pancreatic β-cell dysfunction and apoptosis via interdependent of JNK and AMPK activation-regulated mitochondria-dependent and ER stress-triggered pathways.

    PubMed

    Yang, Tsung-Yuan; Yen, Cheng-Chieh; Lee, Kuan-I; Su, Chin-Chuan; Yang, Ching-Yao; Wu, Chin-Ching; Hsieh, Shang-Shu; Ueng, Kwo-Chang; Huang, Chun-Fa

    2016-03-01

    Molybdenum (Mo), a well-known toxic environmental and industrial pollutant, causes adverse health effects and diseases in humans and has received attention as a potential risk factor for DM. However, the roles of Mo in the mechanisms of the toxicological effects in pancreatic β-cells are mostly unclear. In this study, the results revealed dysfunction of insulin secretion and apoptosis in the pancreatic β-cell-derived RIN-m5F cells and the isolated mouse islets in response to Mo. These effects were accompanied by a mitochondria-dependent apoptotic signals including a decreased in the MMP, an increase in cytochrome c release, and the activation of caspase cascades and PARP. In addition, ER stress was triggered as indicated by several key molecules of the UPR. Furthermore, exposure to Mo induced the activation of ERK1/2, JNK, AMPKα, and GSK3-α/β. Pretreatment with specific pharmacological inhibitors (in RIN-m5F cells and isolated mouse islets) of JNK (SP600125) and AMPK (Compound C) or transfection with si-RNAs (in RIN-m5F cells) specific to JNK and AMPKα effectively prevented the Mo-induced apoptosis and related signals, but inhibitors of ERK1/2 and GSK3-α/β (PD98059 and LiCl, respectively) did not reverse the Mo-induced effects. Additionally, both the inhibitors and specific si-RNAs could suppress the Mo-induced phosphorylation of JNK and AMPKα each other. Taken together, these results suggest that Mo exerts its cytotoxicity on pancreatic β-cells by inducing dysfunction and apoptosis via interdependent JNK and AMPK activation downstream-regulated mitochondrial-dependent and ER stress-triggered apoptosis pathways.

  15. PACAP Protects Adult Neural Stem Cells from the Neurotoxic Effect of Ketamine Associated with Decreased Apoptosis, ER Stress and mTOR Pathway Activation

    PubMed Central

    Mansouri, Shiva; Agartz, Ingrid; Ögren, Sven-Ove; Patrone, Cesare; Lundberg, Mathias

    2017-01-01

    Ketamine administration is a well-established approach to mimic experimentally some aspects of schizophrenia. Adult neurogenesis dysregulation is associated with psychiatric disorders, including schizophrenia. The potential role of neurogenesis in the ketamine-induced phenotype is largely unknown. Recent results from human genetic studies have shown the pituitary adenylate cyclase-activating polypeptide (PACAP) gene is a risk factor for schizophrenia. Its potential role on the regulation of neurogenesis in experimental model of schizophrenia remains to be investigated. We aimed to determine whether ketamine affects the viability of adult neural stem cells (NSC). We also investigated whether the detrimental effect mediated by ketamine could be counteracted by PACAP. NSCs were isolated from the subventricular zone of the mouse and exposed to ketamine with/without PACAP. After 24 hours, cell viability, potential involvement of apoptosis, endoplasmic reticulum (ER) stress, mTOR and AMPA pathway activation were assessed by quantitative RT-PCR and Western blot analysis. We show that ketamine impairs NSC viability in correlation with increased apoptosis, ER stress and mTOR activation. The results also suggest that the effect of ketamine occurs via AMPA receptor activation. Finally, we show that PACAP counteracted the decreased NSC viability induced by ketamine via the specific activation of the PAC-1 receptor subtype. Our study shows that the NSC viability may be negatively affected by ketamine with putative importance for the development of a schizophrenia phenotype in the ketamine induced animal model of schizophrenia. The neuroprotective effect via PAC-1 activation suggests a potentially novel pharmacological target for the treatment of schizophrenia, via neurogenesis normalization. PMID:28125634

  16. Curcumin induces apoptosis in human non-small cell lung cancer NCI-H460 cells through ER stress and caspase cascade- and mitochondria-dependent pathways.

    PubMed

    Wu, Shin-Hwar; Hang, Liang-Wen; Yang, Jai-Sing; Chen, Hung-Yi; Lin, Hui-Yi; Chiang, Jo-Hua; Lu, Chi-Cheng; Yang, Jiun-Long; Lai, Tung-Yuan; Ko, Yang-Ching; Chung, Jing-Gung

    2010-06-01

    It has been reported that curcumin inhibited various types of cancer cells in vitro and in vivo. However, mechanisms of curcumin-inhibited cell growth and -induced apoptosis in human non-small cell lung cancer cells (NCI-H460) still remain unclear. In this study, NCI-H460 cells were treated with curcumin to determine its anticancer activity. Different concentrations of curcumin were used for different durations in NCI-H460 cells and the subsequent changes in the cell morphology, viability, cell cycle, mRNA and protein expressions were determined. Curcumin induced apoptotic morphologic changes in NCI-H460 cells in a dose-dependent manner. After curcumin treatment, BAX and BAD were up-regulated, BCL-2, BCL-X(L) and XIAP were down-regulated. In addition, reactive oxygen species (ROS), intracellular Ca(2+) and endoplasmic reticulum (ER) stress were increased in NCI-H460 cells after exposure to curcumin. These signals led to a loss of mitochondrial membrane potential (Delta Psi(m)) and culminated in caspase-3 activation. Curcumin-induced apoptosis was also stimulated through the FAS/caspase-8 (extrinsic) pathway and ER stress proteins, growth arrest- and DNA damage-inducible gene 153 (GADD153) and glucose-regulated protein 78 (GRP78) were activated in the NCI-H460 cells. Apoptotic cell death induced by curcumin was significantly reversed by pretreatment with ROS scavenger or caspase-8 inhibitor. Furthermore, the NCI-H460 cells tended to be arrested at the G(2)/M cell cycle stage after curcumin treatment and down-regulation of cyclin-dependent kinase 1 (CDK1) may be involved. In summary, curcumin exerts its anticancer effects on lung cancer NCI-H460 cells through apoptosis or cell cycle arrest.

  17. ESCRT components regulate the expression of the ER/Golgi calcium pump gene PMR1 through the Rim101/Nrg1 pathway in budding yeast.

    PubMed

    Zhao, Yunying; Du, Jingcai; Xiong, Bing; Xu, Huihui; Jiang, Linghuo

    2013-10-01

    The endosomal sorting complex required for transport (ESCRT) complexes function to form multivesicular bodies for sorting of proteins destined for the yeast vacuole or the mammalian lysosome. ESCRT components are well conserved in eukaryotes, and their mutations cause neurodegenerative diseases and other cellular pathologies in humans. PMR1 is the orthologous gene of two human genes for calcium pumps secretory pathway Ca(2+)-ATPase (SPCA1, ATP2C1) and sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA, ATP2A2), which are mutated in Hailey-Hailey and Darier genetic diseases, respectively. Here we show that deletion mutation of ESCRT components Snf7, Snf8, Stp22, Vps20, Vps25, Vps28, or Vps36 activates the calcium/calcineurin signaling in yeast cells, but surprisingly leads to a nearly 50% reduction in expression of the ER/Golgi calcium pump gene PMR1 independent of calcium stress. These ESCRT mutants are known to have a defect in Rim101 activation. Ectopic expression of a constitutively active form of Rim101 or further deletion of NRG1 in these mutants partially suppresses their calcium hypersensitivity. Deletion of NRG1 also completely rescues the expression of PMR1 in these mutants to the level of the wild type. Promoter mutagenesis, gel electrophoretic mobility shift assay, and chromatin immunoprecipitation analysis demonstrate that Nrg1 binds to two motifs in the PMR1 promoter. In addition, expression of PMR1 under the control of its promoters with mutated Nrg1-binding motifs suppresses the calcium hypersensitivity of these ESCRT mutants. Collectively, these data have uncovered a function of ESCRT components in regulating PMR1 expression through the Nrg1/Rim101 pathway. Our findings provide important clues for understanding human diseases related to calcium homeostasis.

  18. Diosgenin and 5-Methoxypsoralen Ameliorate Insulin Resistance through ER-α/PI3K/Akt-Signaling Pathways in HepG2 Cells

    PubMed Central

    Dong, Hui; Jiang, Shujun; Li, Fen; Wang, Dingkun; Yang, Desen; Gong, Jing; Huang, Wenya

    2016-01-01

    To determine the effects and the underlying mechanism of diosgenin (DSG) and 5-methoxypsoralen (5-MOP), two main active components in the classical Chinese prescription Hu-Lu-Ba-Wan (HLBW), on insulin resistance, HepG2 cells were incubated in medium containing insulin. Treatments with DSG, 5-MOP, and their combination were performed, respectively. The result showed that the incubation of HepG2 cells with high concentration insulin markedly decreased glucose consumption and glycogen synthesis. However, treatment with DSG, 5-MOP, or their combination significantly reversed the condition and increased the phosphorylated expression of estrogen receptor-α (ERα), sarcoma (Src), Akt/protein kinase B, glycogen synthase kinase-3β (GSK-3β), and the p85 regulatory subunit of phosphatidylinositol 3-kinase p85 (PI3Kp85). At the transcriptional level, expression of the genes mentioned above also increased except for the negative regulation of GSK-3β mRNA. The increased expression of glucose transport-4 (GLUT-4) was meanwhile observed through immunofluorescence. Nevertheless, the synergistic effect of DSG and 5-MOP on improving glycometabolism was not obvious in the present study. These results suggested that DSG and 5-MOP may improve insulin resistance through an ER-mediated PI3K/Akt activation pathway which may be a new strategy for type 2 diabetes mellitus, especially for women in an estrogen-deficient condition. PMID:27656241

  19. ER Stress and Angiogenesis.

    PubMed

    Binet, François; Sapieha, Przemyslaw

    2015-10-06

    Proper tissue vascularization is vital for cellular function as it delivers oxygen, nutrients, hormones, and immune cells and helps to clear cellular debris and metabolic waste products. Tissue angiogenesis occurs to satisfy energy requirements and cellular sensors of metabolic imbalance coordinate vessel growth. In this regard, the classical pathways of the unfolded protein response activated under conditions of ER stress have recently been described to generate angiomodulatory or angiostatic signals. This review elaborates on the link between angiogenesis and ER stress and discusses the implications for diseases characterized by altered vascular homeostasis, such as cancer, retinopathies, and atherosclerosis.

  20. The NAC domain-containing protein, GmNAC6, is a downstream component of the ER stress- and osmotic stress-induced NRP-mediated cell-death signaling pathway

    PubMed Central

    2011-01-01

    Background The endoplasmic reticulum (ER) is a major signaling organelle, which integrates a variety of responses against physiological stresses. In plants, one such stress-integrating response is the N-rich protein (NRP)-mediated cell death signaling pathway, which is synergistically activated by combined ER stress and osmotic stress signals. Despite the potential of this integrated signaling to protect plant cells against different stress conditions, mechanistic knowledge of the pathway is lacking, and downstream components have yet to be identified. Results In the present investigation, we discovered an NAC domain-containing protein from soybean, GmNAC6 (Glycine max NAC6), to be a downstream component of the integrated pathway. Similar to NRP-A and NRP-B, GmNAC6 is induced by ER stress and osmotic stress individually, but requires both signals for full activation. Transient expression of GmNAC6 promoted cell death and hypersensitive-like responses in planta. GmNAC6 and NRPs also share overlapping responses to biotic signals, but the induction of NRPs peaked before the increased accumulation of GmNAC6 transcripts. Consistent with the delayed kinetics of GmNAC6 induction, increased levels of NRP-A and NRP-B transcripts induced promoter activation and the expression of the GmNAC6 gene. Conclusions Collectively, our results biochemically link GmNAC6 to the ER stress- and osmotic stress-integrating cell death response and show that GmNAC6 may act downstream of the NRPs. PMID:21943253

  1. ER-Dependent Ca++-mediated Cytosolic ROS as an Effector for Induction of Mitochondrial Apoptotic and ATM-JNK Signal Pathways in Gallic Acid-treated Human Oral Cancer Cells.

    PubMed

    Lu, Yao-Cheng; Lin, Meng-Liang; Su, Hong-Lin; Chen, Shih-Shun

    2016-02-01

    Release of calcium (Ca(++)) from the endoplasmic reticulum (ER) has been proposed to be involved in induction of apoptosis by oxidative stress. Using inhibitor of ER Ca(++) release dantrolene and inhibitor of mitochondrial Ca(++) uptake Ru-360, we demonstrated that Ca(++) release from the ER was associated with generation of reactive oxygen species (ROS), loss of mitochondrial membrane potential, and apoptosis of human oral cancer (OC) cells induced by gallic acid (GA). Small interfering RNA-mediated suppression of protein kinase RNA-like endoplasmic reticulum kinase inhibited tunicamycin-induced induction of 78 kDa glucose-regulated protein, C/EBP homologous protein, pro-caspase-12 cleavage, cytosolic Ca(++) increase and apoptosis, but did not attenuate the increase in cytosolic Ca(++) level and apoptosis induced by GA. Ataxia telangiectasia mutated (ATM)-mediated c-Jun N-terminal kinase (JNK) phosphorylation and apoptosis by GA was blocked by dantrolene. The specificity of ROS-mediated ATM-JNK activation was confirmed by treatment with N-acetylcysteine, a ROS scavenger. Blockade of ATM activation by specific inhibitor KU55933, short hairpin RNA, or kinase-dead ATM overexpression suppressed JNK phosphorylation but did not completely inhibit cytosolic ROS production, mitochondrial cytochrome c release, pro-caspase-3 cleavage, and apoptosis induced by GA. Taken together, these results indicate that GA induces OC cell apoptosis by inducing the activation of mitochondrial apoptotic and ATM-JNK signal pathways, likely through ER Ca(++)-mediated ROS production.

  2. The research on lapatinib in autophagy, cell cycle arrest and epithelial to mesenchymal transition via Wnt/ErK/PI3K-AKT signaling pathway in human cutaneous squamous cell carcinoma

    PubMed Central

    Yao, Ming; Shang, Yuan-Yuan; Zhou, Zhi-Wei; Yang, Yin-Xue; Wu, Yin-Sheng; Guan, Li-Feng; Wang, Xin-Yu; Zhou, Shu-Feng; Wei, Xi

    2017-01-01

    Cutaneous squamous cell carcinoma (cSCC) contributes to one of most common types of skin cancer. Epidermal growth factor receptor (EGFR) activation has been investigated to be associated with the development of cSCC. Lapatinib is an inhibitor targeting HER2/neu and EGFR pathway. We found that lapatinib can inhibit proliferation by enhancing apoptosis of human cSCC cell lines. The cSCC cell cycle distribution could be arrested in G2/M phase after lapatinib treatment. In the in vitro experiment, we found that lapatinib interrupted PI3K/AKT/mTOR signaling pathway in human cSCC cells. Furthermore, lapatinib could suppress epithelial to mesenchymal transition (EMT) via Wnt/ErK/PI3K-AKT signaling pathway to represent a promising anticancer drug for cSCC treatment. PMID:28243326

  3. TEMPERATURE-SENSITIVE, POST-TRANSLATIONAL REGULATION OF PLANT OMEGA-3 FATTY ACID DESATURASES IS MEDIATED BY THE ER-ASSOCIATED DEGRADATION PATHWAY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In plants, the endoplasmic reticulum (ER)-localized omega-3 fatty acid desaturases (Fad3s) increase the production of polyunsaturated fatty acids at cooler temperatures, but the FAD3 genes themselves are typically not upregulated during this adaptive response. Here, we expressed two closely related ...

  4. ER stress-induced cell death mechanisms

    PubMed Central

    Sano, Renata; Reed, John C.

    2013-01-01

    The endoplasmic-reticulum (ER) stress response constitutes a cellular process that is triggered by a variety of conditions that disturb folding of proteins in the ER. Eukaryotic cells have developed an evolutionarily conserved adaptive mechanism, the unfolded protein response (UPR), which aims to clear unfolded proteins and restore ER homeostasis. In cases where ER stress cannot be reversed, cellular functions deteriorate, often leading to cell death. Accumulating evidence implicates ER stress-induced cellular dysfunction and cell death as major contributors to many diseases, making modulators of ER stress pathways potentially attractive targets for therapeutics discovery. Here, we summarize recent advances in understanding the diversity of molecular mechanisms that govern ER stress signaling in health and disease. PMID:23850759

  5. Down-regulation of 14-3-3β exerts anti-cancer effects through inducing ER stress in human glioma U87 cells: Involvement of CHOP–Wnt pathway

    SciTech Connect

    Cao, Lei; Lei, Hui; Chang, Ming-Ze; Liu, Zhi-Qin; Bie, Xiao-Hua

    2015-07-10

    We previously identified 14-3-3β as a tumor-specific isoform of 14-3-3 protein in astrocytoma, but its functional role in glioma cells and underlying mechanisms are poorly understood. In the present study, we investigated the effects of 14-3-3β inhibition in human glioma U87 cells using specific targeted small interfering RNA (siRNA). The results showed that 14-3-3β is highly expressed in U87 cells but not in normal astrocyte SVGp12 cells. Knockdown of 14-3-3β by Si-14-3-3β transfection significantly decreased the cell viability but increased the LDH release in a time-dependent fashion in U87 cells, and these effects were accompanied with G0/G1 cell cycle arrest and apoptosis. In addition, 14-3-3β knockdown induced ER stress in U87 cells, as evidenced by ER calcium release, increased expression of XBP1S mRNA and induction of ER related pro-apoptotic factors. Down-regulation of 14-3-3β significantly decreased the nuclear localization of β-catenin and inhibited Topflash activity, which was shown to be reversely correlated with CHOP. Furthermore, Si-CHOP and sFRP were used to inhibit CHOP and Wnt, respectively. The results showed that the anti-cancer effects of 14-3-3β knockdown in U87 cells were mediated by increased expression of CHOP and followed inhibition of Wnt/β-catenin pathway. In summary, the remarkable efficiency of 14-3-3β knockdown to induce apoptotic cell death in U87 cells may find therapeutic application for the treatment of glioma patients. - Highlights: • Knockdown of 14-3-3β leads to cytotoxicity in human glioma U87 cells. • Knockdown of 14-3-3β induces cell cycle arrest and apoptosis in U87 cells. • Knockdown of 14-3-3β results in ER stress in U87 cells. • Knockdown of 14-3-3β inhibits Wnt/β-catenin pathway via CHOP activation.

  6. The changing role of ER in endocrine resistance.

    PubMed

    Nardone, Agostina; De Angelis, Carmine; Trivedi, Meghana V; Osborne, C Kent; Schiff, Rachel

    2015-11-01

    Estrogen receptor (ER) is expressed in approximately 70% of newly diagnosed breast tumors. Although endocrine therapy targeting ER is highly effective, intrinsic or acquired resistance is common, significantly jeopardizing treatment outcomes and minimizing overall survival. Even in the presence of endocrine resistance, a continued role of ER signaling is suggested by several lines of clinical and preclinical evidence. Indeed, inhibition or down-regulation of ER reduces tumor growth in preclinical models of acquired endocrine resistance, and many patients with recurrent ER+ breast tumors progressing on one type of ER-targeted treatment still benefit from sequential endocrine treatments that target ER by a different mechanism. New insights into the nature and biology of ER have revealed several mechanisms sustaining altered ER signaling in endocrine-resistant tumors, including deregulated growth factor receptor signaling that results in ligand-independent ER activation, unbalanced ER co-regulator activity, and genomic alterations involving the ER gene ESR1. Therefore, biopsies of recurrent lesions are needed to assess the changes in epi/genomics and signaling landscape of ER and associated pathways in order to tailor therapies to effectively overcome endocrine resistance. In addition, more completely abolishing the levels and activity of ER and its co-activators, in combination with selected signal transduction inhibitors or agents blocking the upstream or downstream targets of the ER pathway, may provide a better therapeutic strategy in combating endocrine resistance.

  7. 5-Hydroxymethylfurfural protects against ER stress-induced apoptosis in GalN/TNF-α-injured L02 hepatocytes through regulating the PERK-eIF2α signaling pathway.

    PubMed

    Jiang, Ze-Qun; Ma, Yan-Xia; Li, Mu-Han; Zhan, Xiu-Qin; Zhang, Xu; Wang, Ming-Yan

    2015-12-01

    5-Hydroxymethylfurfural (5-HMF), a water-soluble compound extracted from wine-processed Fructus corni, is a novel hepatic protectant for treating acute liver injury. The present study was designed to investigate the protective effect of 5-HMF in human L02 hepatocytes injured by D-galactosamine (GalN) and tumor necrosis factor-α (TNF-α) in vitro and to explore the underlying mechanisms of action. Our results showed that 5-HMF caused significant increase in the viability of L02 cells injured by GalN/TNF-α, in accordance with a dose-dependent decrease in apoptotic cell death confirmed by morphological and flow cytometric analyses. Based on immunofluorescence and Western blot assays, we found that GalN/TNF-α induced ER stress in the cells, as indicated by the disturbance of intracellular Ca(2+) concentration, the activation of protein kinase RNA (PKR)-like ER kinase (PERK), phosphorylation of eukaryotic initiation factor 2 alpha (eIF2α), and expression of ATF4 and CHOP proteins, which was reversed by 5-HMF pre-treatment in a dose-dependent manner. The anti-apoptotic effect of 5-HMF was further evidenced by balancing the expression of Bcl-2 family members. In addition, the knockdown of PERK suppressed the expression of phospho-PERK, phospho-eIF2α, ATF4, and CHOP, resulting in a significant decrease in cell apoptosis after the treatment with GalN/TNF-α. 5-HMF could enhance the effects of PERK knockdown, protecting the cells against the GalN/TNF-α insult. In conclusion, these findings demonstrate that 5-HMF can effectively protect GalN/TNF-α-injured L02 hepatocytes against ER stress-induced apoptosis through the regulation of the PERK-eIF2α signaling pathway, suggesting that it is a possible candidate for liver disease therapy.

  8. A Role for Macro-ER-Phagy in ER Quality Control.

    PubMed

    Lipatova, Zhanna; Segev, Nava

    2015-07-01

    The endoplasmic-reticulum quality-control (ERQC) system shuttles misfolded proteins for degradation by the proteasome through the well-defined ER-associated degradation (ERAD) pathway. In contrast, very little is known about the role of autophagy in ERQC. Macro-autophagy, a collection of pathways that deliver proteins through autophagosomes (APs) for degradation in the lysosome (vacuole in yeast), is mediated by autophagy-specific proteins, Atgs, and regulated by Ypt/Rab GTPases. Until recently, the term ER-phagy was used to describe degradation of ER membrane and proteins in the lysosome under stress: either ER stress induced by drugs or whole-cell stress induced by starvation. These two types of stresses induce micro-ER-phagy, which does not use autophagic organelles and machinery, and non-selective autophagy. Here, we characterize the macro-ER-phagy pathway and uncover its role in ERQC. This pathway delivers 20-50% of certain ER-resident membrane proteins to the vacuole and is further induced to >90% by overexpression of a single integral-membrane protein. Even though such overexpression in cells defective in macro-ER-phagy induces the unfolded-protein response (UPR), UPR is not needed for macro-ER-phagy. We show that macro-ER-phagy is dependent on Atgs and Ypt GTPases and its cargo passes through APs. Moreover, for the first time the role of Atg9, the only integral-membrane core Atg, is uncoupled from that of other core Atgs. Finally, three sequential steps of this pathway are delineated: Atg9-dependent exit from the ER en route to autophagy, Ypt1- and core Atgs-mediated pre-autophagsomal-structure organization, and Ypt51-mediated delivery of APs to the vacuole.

  9. Ozone (O{sub 3}) elicits neurotoxicity in spinal cord neurons (SCNs) by inducing ER Ca{sup 2+} release and activating the CaMKII/MAPK signaling pathway

    SciTech Connect

    Li, Yun; Lin, Xiaowen; Zhao, XueJun; Xie, Juntian; JunNan, Wang; Sun, Tao; Fu, Zhijian

    2014-11-01

    Ozone (O{sub 3}) is widely used in the treatment of spinal cord related diseases. Excess or accumulation of this photochemical air can however be neurotoxic. In this study, in vitro cultured Wister rat spinal cord neurons (SCNs) were used to investigate the detrimental effects and underlying mechanisms of O{sub 3}. Ozone in a dose-dependent manner inhibited cell viability at a range of 20 to 500 μg/ml, with the dose at 40 μg/ml resulting in a decrease of cell viability to 75%. The cell death after O{sub 3} exposure was related to endoplasmic reticulum (ER) calcium (Ca{sup 2+}) release. Intracellular Ca{sup 2+} chelator, ER stabilizer (inositol 1,4,5-trisphosphate receptor (IP3R) antagonist and ryanodine receptor (RyR) antagonist) and calcium/calmodulin-dependent protein kinase II (CaMKII) antagonist could effectively block Ca{sup 2+} mobilization and inhibit cell death following 40 μg/ml O{sub 3} exposure. In addition, ER Ca{sup 2+} release due to O{sub 3} exposure enhanced phospho-p38 and phospho-JNK levels and apoptosis of SCNs through activating CaMKII. Based on these results, we confirm that ozone elicits neurotoxicity in SCNs via inducing ER Ca{sup 2+} release and activating CaMKII/MAPK signaling pathway. Therefore, physicians should get attention to the selection of treatment concentrations of oxygen/ozone. And, approaches, such as chelating intracellular Ca{sup 2+} and stabilizing neuronal Ca{sup 2+} homeostasis could effectively ameliorate the neurotoxicity of O{sub 3}. - Highlights: • Exposure to O{sub 3} can reduce the viability of SCNs and cause the cell death. • Exposure to O{sub 3} can trigger RyR and IP3R dependent intracellular Ca{sup 2+} release. • Exposure to O{sub 3} can enhance the phospho-CaMKII, phospho-JNK and phospho-p38 levels.

  10. MicroRNAs Meet Calcium: Joint Venture in ER Proteostasis

    PubMed Central

    Finger, Fabian; Hoppe, Thorsten

    2017-01-01

    The endoplasmic reticulum (ER) is a cellular compartment that possesses a key function in protein translation and folding. Maintaining its integrity is of fundamental importance for organism’s physiology and viability. The dynamic regulation of intraluminal ER Ca2+ concentration directly influences the activity of ER-resident chaperones and stress response pathways that balance protein load and folding capacity. Here, we review the emerging evidence that microRNAs play important roles in adjusting these processes to frequently changing intracellular and environmental conditions to modify ER Ca2+ handling and storage and maintain ER homeostasis. PMID:25372053

  11. MicroRNAs meet calcium: joint venture in ER proteostasis.

    PubMed

    Finger, Fabian; Hoppe, Thorsten

    2014-11-04

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

  12. Reticulons Regulate the ER Inheritance Block during ER Stress.

    PubMed

    Piña, Francisco Javier; Fleming, Tinya; Pogliano, Kit; Niwa, Maho

    2016-05-09

    Segregation of functional organelles during the cell cycle is crucial to generate healthy daughter cells. In Saccharomyces cerevisiae, ER stress causes an ER inheritance block to ensure cells inherit a functional ER. Here, we report that formation of tubular ER in the mother cell, the first step in ER inheritance, depends on functional symmetry between the cortical ER (cER) and perinuclear ER (pnER). ER stress induces functional asymmetry, blocking tubular ER formation and ER inheritance. Using fluorescence recovery after photobleaching, we show that the ER chaperone Kar2/BiP fused to GFP and an ER membrane reporter, Hmg1-GFP, behave differently in the cER and pnER. The functional asymmetry and tubular ER formation depend on Reticulons/Yop1, which maintain ER structure. LUNAPARK1 deletion in rtn1Δrtn2Δyop1Δ cells restores the pnER/cER functional asymmetry, tubular ER generation, and ER inheritance blocks. Thus, Reticulon/Yop1-dependent changes in ER structure are linked to ER inheritance during the yeast cell cycle.

  13. The Aspergillus nidulans peripheral ER: disorganization by ER stress and persistence during mitosis.

    PubMed

    Markina-Iñarrairaegui, Ane; Pantazopoulou, Areti; Espeso, Eduardo A; Peñalva, Miguel A

    2013-01-01

    The genetically amenable fungus Aspergillus nidulans is well suited for cell biology studies involving the secretory pathway and its relationship with hyphal tip growth by apical extension. We exploited live-cell epifluorescence microscopy of the ER labeled with the translocon component Sec63, endogenously tagged with GFP, to study the organization of 'secretory' ER domains. The Sec63 A. nidulans ER network includes brightly fluorescent peripheral strands and more faintly labeled nuclear envelopes. In hyphae, the most abundant peripheral ER structures correspond to plasma membrane-associated strands that are polarized, but do not invade the hyphal tip dome, at least in part because the subapical collar of endocytic actin patches constrict the cortical strands in this region. Thus the subapical endocytic ring might provide an attachment for ER strands, thereby ensuring that the growing tip remains 'loaded' with secretory ER. Acute disruption of secretory ER function by reductive stress-mediated induction of the unfolded protein response results in the reversible aggregation of ER strands, cessation of exocytosis and swelling of the hyphal tips. The secretory ER is insensitive to brefeldin A treatment and does not undergo changes during mitosis, in agreement with the reports that apical extension continues at normal rates during this period.

  14. Tamoxifen Action in ER-Negative Breast Cancer.

    PubMed

    Manna, Subrata; Holz, Marina K

    2016-02-10

    Breast cancer is a highly heterogeneous disease. Tamoxifen is a selective estrogen receptor (ER) modulator and is mainly indicated for the treatment of breast cancer in postmenopausal women and postsurgery neoadjuvant therapy in ER-positive breast cancers. Interestingly, 5-10% of the ER-negative breast cancers have also shown sensitivity to tamoxifen treatment. The involvement of molecular markers and/or signaling pathways independent of ER signaling has been implicated in tamoxifen sensitivity in the ER-negative subgroup. Studies reveal that variation in the expression of estrogen-related receptor alpha, ER subtype beta, tumor microenvironment, and epigenetics affects tamoxifen sensitivity. This review discusses the background of the research on the action of tamoxifen that may inspire future studies to explore effective therapeutic strategies for the treatment of ER-negative and triple-negative breast cancers, the latter being an aggressive disease with worse clinical outcome.

  15. Tamoxifen Action in ER-Negative Breast Cancer

    PubMed Central

    Manna, Subrata; Holz, Marina K.

    2016-01-01

    Breast cancer is a highly heterogeneous disease. Tamoxifen is a selective estrogen receptor (ER) modulator and is mainly indicated for the treatment of breast cancer in postmenopausal women and postsurgery neoadjuvant therapy in ER-positive breast cancers. Interestingly, 5–10% of the ER-negative breast cancers have also shown sensitivity to tamoxifen treatment. The involvement of molecular markers and/or signaling pathways independent of ER signaling has been implicated in tamoxifen sensitivity in the ER-negative subgroup. Studies reveal that variation in the expression of estrogen-related receptor alpha, ER subtype beta, tumor microenvironment, and epigenetics affects tamoxifen sensitivity. This review discusses the background of the research on the action of tamoxifen that may inspire future studies to explore effective therapeutic strategies for the treatment of ER-negative and triple-negative breast cancers, the latter being an aggressive disease with worse clinical outcome. PMID:26989346

  16. Links between ER stress and autophagy in plants.

    PubMed

    Pu, Yunting; Bassham, Diane C

    2013-06-01

    Autophagy is a major pathway for the delivery of proteins or organelles to be degraded in the vacuole and recycled. It can be induced by abiotic stresses, senescence, and pathogen infection. Recent research has shown that autophagy is activated by ER stress. Here we review the major progress that has been made in the study of autophagy and ER stress in plants, and describe the links between ER stress and autophagy to guide further study on how autophagy is regulated in response to ER stress.

  17. ER chaperones in neurodegenerative disease: Folding and beyond.

    PubMed

    Garcia-Huerta, Paula; Bargsted, Leslie; Rivas, Alexis; Matus, Soledad; Vidal, Rene L

    2016-10-01

    Proteins along the secretory pathway are co-translationally translocated into the lumen of the endoplasmic reticulum (ER) as unfolded polypeptide chains. Afterwards, they are usually modified with N-linked glycans, correctly folded and stabilized by disulfide bonds. ER chaperones and folding enzymes control these processes. The accumulation of unfolded proteins in the ER activates a signaling response, termed the unfolded protein response (UPR). The hallmark of this response is the coordinated transcriptional up-regulation of ER chaperones and folding enzymes. In order to discuss the importance of the proper folding of certain substrates we will address the role of ER chaperones in normal physiological conditions and examine different aspects of its contribution in neurodegenerative disease. This article is part of a Special Issue entitled SI:ER stress.

  18. Role of SERCA1 Truncated Isoform in the Proapoptotic Calcium Transfer from ER to Mitochondria during ER Stress

    PubMed Central

    Chami, Mounia; Oulès, Bénédicte; Szabadkai, György; Tacine, Rachida; Rizzuto, Rosario; Paterlini-Bréchot, Patrizia

    2009-01-01

    SUMMARY Among the new players at the endoplasmic reticulum (ER)-mitochondria interface regulating interorganelle calcium signaling, those specifically involved during ER stress are not known at present. We report here that the truncated variant of the sarcoendoplasmic reticulum Ca2+-ATPase 1 (S1T) amplifies ER stress through the PERK-eIF2α-ATF4-CHOP pathway. S1T, which is localized in the ER-mitochondria microdomains, determines ER Ca2+ depletion due to increased Ca2+ leak, an increased number of ER-mitochondria contact sites, and inhibition of mitochondria movements. This leads to increased Ca2+ transfer to mitochondria in both resting and stimulated conditions and activation of the mitochondrial apoptotic pathway. Interestingly, S1T knockdown was shown to prevent ER stress, mitochondrial Ca2+ overload, and subsequent apoptosis. Thus, by bridging ER stress to apoptosis through increased ER-mitochondria Ca2+ transfer, S1T acts as an essential determinant of cellular fate. PMID:19061639

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

    PubMed

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

    2015-08-01

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

  20. ER-2 in flight

    NASA Technical Reports Server (NTRS)

    1996-01-01

    In this film clip, we see an ER-2 on its take off roll and climb as it departs from runway 22 at Edwards AFB, California. In 1981, NASA acquired its first ER-2 aircraft. The agency obtained a second ER-2 in 1989. These airplanes replaced two Lockheed U-2 aircraft, which NASA had used to collect scientific data since 1971. The U-2, and later the ER-2, were based at the Ames Research Center, Moffett Field, California, until 1997. In 1997, the ER-2 aircraft and their operations moved to NASA Dryden Flight Research Center, Edwards, California. Since the inaugural flight for this program, August 31, 1971, NASA U-2 and ER-2 aircraft have flown more than 4,000 data missions and test flights in support of scientific research conducted by scientists from NASA, other federal agencies, states, universities, and the private sector. NASA is currently using two ER-2 Airborne Science aircraft as flying laboratories. The aircraft, based at NASA Dryden, collect information about our surroundings, including Earth resources, celestial observations, atmospheric chemistry and dynamics, and oceanic processes. The aircraft also are used for electronic sensor research and development, satellite calibration, and satellite data validation. The ER-2 is a versatile aircraft well-suited to perform multiple mission tasks. It is 30 percent larger than the U-2 with a 20 feet longer wingspan and a considerably increased payload over the older airframe. The aircraft has four large pressurized experiment compartments and a high-capacity AC/DC electrical system, permitting it to carry a variety of payloads on a single mission. The modular design of the aircraft permits rapid installation or removal of payloads to meet changing mission requirements. The ER-2 has a range beyond 3,000 miles (4800 kilometers); is capable of long flight duration and can operate at altitudes up to 70,000 feet (21.3 kilometers) if required. Operating at an altitude of 65,000 feet (19.8 kilometers) the ER-2 acquires data

  1. Ire1 supports normal ER differentiation in developing Drosophila photoreceptors

    PubMed Central

    Xu, Zuyuan; Chikka, Madhusudana Rao; Xia, Hongai; Ready, Donald F.

    2016-01-01

    ABSTRACT The endoplasmic reticulum (ER) serves virtually all aspects of cell physiology and, by pathways that are incompletely understood, is dynamically remodeled to meet changing cell needs. Inositol-requiring enzyme 1 (Ire1), a conserved core protein of the unfolded protein response (UPR), participates in ER remodeling and is particularly required during the differentiation of cells devoted to intense secretory activity, so-called ‘professional’ secretory cells. Here, we characterize the role of Ire1 in ER differentiation in the developing Drosophila compound eye photoreceptors (R cells). As part of normal development, R cells take a turn as professional secretory cells with a massive secretory effort that builds the photosensitive membrane organelle, the rhabdomere. We find rough ER sheets proliferate as rhabdomere biogenesis culminates, and Ire1 is required for normal ER differentiation. Ire1 is active early in R cell development and is required in anticipation of peak biosynthesis. Without Ire1, the amount of rough ER sheets is strongly reduced and the extensive cortical ER network at the rhabdomere base, the subrhabdomere cisterna (SRC), fails. Instead, ER proliferates in persistent and ribosome-poor tubular tangles. A phase of Ire1 activity early in R cell development thus shapes dynamic ER. PMID:26787744

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

    SciTech Connect

    Mera, Kentaro; Kawahara, Ko-ichi; Tada, Ko-ichi; Kawai, Kazuhiro; Hashiguchi, Teruto; Maruyama, Ikuro; Kanekura, Takuro

    2010-06-25

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

  3. ER stress, autophagy, and RNA viruses

    PubMed Central

    Jheng, Jia-Rong; Ho, Jin-Yuan; Horng, Jim-Tong

    2014-01-01

    Endoplasmic reticulum (ER) stress is a general term for representing the pathway by which various stimuli affect ER functions. ER stress induces the evolutionarily conserved signaling pathways, called the unfolded protein response (UPR), which compromises the stimulus and then determines whether the cell survives or dies. In recent years, ongoing research has suggested that these pathways may be linked to the autophagic response, which plays a key role in the cell's response to various stressors. Autophagy performs a self-digestion function, and its activation protects cells against certain pathogens. However, the link between the UPR and autophagy may be more complicated. These two systems may act dependently, or the induction of one system may interfere with the other. Experimental studies have found that different viruses modulate these mechanisms to allow them to escape the host immune response or, worse, to exploit the host's defense to their advantage; thus, this topic is a critical area in antiviral research. In this review, we summarize the current knowledge about how RNA viruses, including influenza virus, poliovirus, coxsackievirus, enterovirus 71, Japanese encephalitis virus, hepatitis C virus, and dengue virus, regulate these processes. We also discuss recent discoveries and how these will produce novel strategies for antiviral treatment. PMID:25140166

  4. Characterization of an ICII82, 780-Induced, Estrogen Receptor (ER)-beta Mediated Apoptotic Pathway in Prostate Cancer Cells and Establishment of (ER)-beta-Regulated Electrophile-Processing Phase II Enzyme Downregulation as a Promotional Factor in Human Prostatic Carcinogenesis

    DTIC Science & Technology

    2001-05-01

    sore (preCe animls 38-1).Pardoxcaly, DS, AMandothr etroens in a PrEC preparation purchased from a commercial source (PrEC;animals (38-41...however, its cells derived from carcinoma and hyperplasia of the prostate in monolayer cell culture. A possible in vitro model for clinical chemotherapy. J...Makela S, Santti R: Animal models for thd preeoplsi~cthe spread of cells with either ER isoform from the primary lesions of the prostate. Eur Urol

  5. Trip to ER

    PubMed Central

    Ma, Xuan; Cao, Xiaofeng; Mo, Beixin; Chen, Xuemei

    2013-01-01

    miRNAs elicit gene silencing at the post-transcriptional level by several modes of action: translational repression, mRNA decay, and mRNA cleavage. Studies in animals have suggested that translational repression occurs at early steps of translation initiation, which can be followed by deadenylation and mRNA decay. Plant miRNAs were originally thought to solely participate in mRNA cleavage, but increasing evidence has indicated that they are also commonly involved in translational inhibition. Here we discuss recent findings on miRNA-mediated translational repression in plants. The identification of AMP1 in Arabidopsis as a protein required for the translational repression but not the mRNA cleavage activity of miRNAs links miRNA-based translational repression to the endoplasmic reticulum (ER). Future work is required to further elucidate the miRNA machinery on the ER. PMID:24100209

  6. Bap31 is an itinerant protein that moves between the peripheral endoplasmic reticulum (ER) and a juxtanuclear compartment related to ER-associated Degradation.

    PubMed

    Wakana, Yuichi; Takai, Sawako; Nakajima, Ken-Ichi; Tani, Katsuko; Yamamoto, Akitsugu; Watson, Peter; Stephens, David J; Hauri, Hans-Peter; Tagaya, Mitsuo

    2008-05-01

    Certain endoplasmic reticulum (ER)-associated degradation (ERAD) substrates with transmembrane domains are segregated from other ER proteins and sorted into a juxtanuclear subcompartment, known as the ER quality control compartment. Bap31 is an ER protein with three transmembrane domains, and it is assumed to be a cargo receptor for ER export of some transmembrane proteins, especially those prone to ERAD. Here, we show that Bap31 is a component of the ER quality control compartment and that it moves between the peripheral ER and a juxtanuclear ER or ER-related compartment distinct from the conventional ER-Golgi intermediate compartment. The third and second transmembrane domains of Bap31 are principally responsible for the movement to and recycling from the juxtanuclear region, respectively. This cycling was blocked by depolymerization of microtubules and disruption of dynein-dynactin function. Overexpression of Sar1p and Arf1 mutants affected Bap31 cycling, suggesting that this cycling pathway is related to the conventional vesicular transport pathways.

  7. Naltrexone ER/Bupropion ER: A Review in Obesity Management.

    PubMed

    Greig, Sarah L; Keating, Gillian M

    2015-07-01

    Oral naltrexone extended-release/bupropion extended-release (naltrexone ER/bupropion ER; Contrave(®), Mysimba(™)) is available as an adjunct to a reduced-calorie diet and increased physical activity in adults with an initial body mass index (BMI) of ≥ 30 kg/m(2) (i.e. obese) or a BMI of ≥ 27 kg/m(2) (i.e. overweight) in the presence of at least one bodyweight-related comorbidity, such as type 2 diabetes mellitus, hypertension or dyslipidaemia. In 56-week phase III trials in these patient populations, oral naltrexone ER/bupropion ER 32/360 mg/day was significantly more effective than placebo with regard to percentage bodyweight reductions from baseline and the proportion of patients who achieved bodyweight reductions of ≥ 5 and ≥ 10%. Significantly greater improvements in several cardiometabolic risk factors were also observed with naltrexone ER/bupropion ER versus placebo, as well as greater improvements in glycated haemoglobin levels in obese or overweight adults with type 2 diabetes. Naltrexone ER/bupropion ER was generally well tolerated in phase III trials, with nausea being the most common adverse event. Thus, naltrexone ER/bupropion ER 32/360 mg/day as an adjunct to a reduced-calorie diet and increased physical activity, is an effective and well tolerated option for chronic bodyweight management in obese adults or overweight adults with at least one bodyweight-related comorbidity.

  8. Molecular mechanism aspect of ER stress in Alzheimer's disease: current approaches and future strategies.

    PubMed

    Ansari, Niloufar; Khodagholi, Fariba

    2013-01-01

    Alzheimer's disease (AD) is a progressive neurodegenerative disorder that is characterized by progressive loss of memory and cognitive impairment. Aggregation of amyloid-β (Aβ) peptides is the crucial factor in the onset of AD. The toxic Aβ peptides Aβ40 and Aβ42 are produced from the Aβ precursor protein (APP), a transmembrane protein which is folded and modified in endoplasmic reticulum (ER). ER is the main organelle for the synthesis and processing of nearly all proteins as well as the main cellular source of Ca2+. Under stress conditions, three main ER pathways including inositol-requiring enzyme 1, protein kinase RNA-like ER kinase, and activating transcription factor 6 become activated causing the accumulation of unfolded or misfolded proteins within ER lumen. These pathways manage the stress by regulating the expression of chaperones and enzymes involved in protein folding. Several studies have reported the dysfunction of these stress-sensing pathways in pathological conditions, including neurodegenerative diseases. Recent studies have proposed that neuronal death in AD arises from dysfunction of the ER. Here, we will review recent research findings on the interaction between ER and mitochondria, and its effect on apoptotic pathways. We further provide insights into studies which suggest the role of ER in animal and/or cellular models of AD. Therapeutic strategies that modulate ER could represent a promising approach for prevention or treatment of AD.

  9. Enhance the Er3+ Upconversion Luminescence by Constructing NaGdF4:Er3+@NaGdF4:Er3+ Active-Core/Active-Shell Nanocrystals

    NASA Astrophysics Data System (ADS)

    Du, Xiaoyu; Wang, Xiangfu; Meng, Lan; Bu, Yanyan; Yan, Xiaohong

    2017-03-01

    NaGdF4:12%Er3+@NaGdF4: x%Er3+ ( x = 0, 6, 8, 10, and 12) active-core/active-shell nanoparticles (NPs) were peculiarly synthesized via a delayed nucleation pathway with procedures. The phase, shape, and size of the resulting core-shell NPs are confirmed by transmission electron microscopy and X-ray diffraction. Coated with a NaGdF4:10%Er3+ active shell around the NaGdF4:12%Er3+ core NPs, a maximum luminescent enhancement of about 336 times higher than the NaGdF4:12%Er3+ core-only NPs was observed under the 1540 nm excitation. The intensity ratio of green to red was adjusted through the construction of the core-shell structure and the change of Er3+ concentration in the shell. By analyzing the lifetimes of emission bands and exploring the energy transition mechanism, the giant luminescence enhancement is mainly attributed to the significant increase in the near-infrared absorption at 1540 nm and efficient energy migration from the shell to core.

  10. Enhance the Er(3+) Upconversion Luminescence by Constructing NaGdF4:Er(3+)@NaGdF4:Er(3+) Active-Core/Active-Shell Nanocrystals.

    PubMed

    Du, Xiaoyu; Wang, Xiangfu; Meng, Lan; Bu, Yanyan; Yan, Xiaohong

    2017-12-01

    NaGdF4:12%Er(3+)@NaGdF4:x%Er(3+) (x = 0, 6, 8, 10, and 12) active-core/active-shell nanoparticles (NPs) were peculiarly synthesized via a delayed nucleation pathway with procedures. The phase, shape, and size of the resulting core-shell NPs are confirmed by transmission electron microscopy and X-ray diffraction. Coated with a NaGdF4:10%Er(3+) active shell around the NaGdF4:12%Er(3+) core NPs, a maximum luminescent enhancement of about 336 times higher than the NaGdF4:12%Er(3+) core-only NPs was observed under the 1540 nm excitation. The intensity ratio of green to red was adjusted through the construction of the core-shell structure and the change of Er(3+) concentration in the shell. By analyzing the lifetimes of emission bands and exploring the energy transition mechanism, the giant luminescence enhancement is mainly attributed to the significant increase in the near-infrared absorption at 1540 nm and efficient energy migration from the shell to core.

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

    PubMed

    Yang, Ping; Fu, Shilong; Cao, Zhifei; Liao, Huaidong; Huo, Zihe; Pan, Yanyan; Zhang, Gaochuan; Gao, Aidi; Zhou, Quansheng

    2015-10-15

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

  12. When supply does not meet demand-ER stress and plant programmed cell death

    PubMed Central

    Williams, Brett; Verchot, Jeanmarie; Dickman, Martin B.

    2014-01-01

    The endoplasmic reticulum (ER) is the central organelle in the eukaryotic secretory pathway. The ER functions in protein synthesis and maturation and is crucial for proper maintenance of cellular homeostasis and adaptation to adverse environments. Acting as a cellular sentinel, the ER is exquisitely sensitive to changing environments principally via the ER quality control machinery. When perturbed, ER-stress triggers a tightly regulated and highly conserved, signal transduction pathway known as the unfolded protein response (UPR) that prevents the dangerous accumulation of unfolded/misfolded proteins. In situations where excessive UPR activity surpasses threshold levels, cells deteriorate and eventually trigger programmed cell death (PCD) as a way for the organism to cope with dysfunctional or toxic signals. The programmed cell death that results from excessive ER stress in mammalian systems contributes to several important diseases including hypoxia, neurodegeneration, and diabetes. Importantly, hallmark features and markers of cell death that are associated with ER stress in mammals are also found in plants. In particular, there is a common, conserved set of chaperones that modulate ER cell death signaling. Here we review the elements of plant cell death responses to ER stress and note that an increasing number of plant-pathogen interactions are being identified in which the host ER is targeted by plant pathogens to establish compatibility. PMID:24926295

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

    PubMed

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

    2009-11-30

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

  14. ER stress induces NLRP3 inflammasome activation and hepatocyte death

    PubMed Central

    Lebeaupin, C; Proics, E; de Bieville, C H D; Rousseau, D; Bonnafous, S; Patouraux, S; Adam, G; Lavallard, V J; Rovere, C; Le Thuc, O; Saint-Paul, M C; Anty, R; Schneck, A S; Iannelli, A; Gugenheim, J; Tran, A; Gual, P; Bailly-Maitre, B

    2015-01-01

    inflammation-mediated liver injury in chronic liver diseases. Inhibition of ER-dependent inflammasome activation and cell death pathways may represent a potential therapeutic approach in chronic liver diseases. PMID:26355342

  15. [Optical parameters of Er3+ in Er3+ : YVO4].

    PubMed

    Chen, Ying; Chen, Xiao-bo; Chen, Luan; Liu, Da-he; Song, Zeng-fu; Li, Yong-liang; Li, Song; Zeng, Yong-zhi; Wu, Zheng-long; Zhang, Chun-lin; Wang, Ya-fei; Guo, Jing-hua

    2010-07-01

    In the present paper the authors firstly measured the absorption spectra of Er3+ in the sample Er3+ : YVO4 (0.5%), then calculated the intensity parameters are calculated by using the Judd-Ofelt theory. After that the authors dealed with some predicted spectroscopic parameters, such as the oscillator strength, spontaneous radiative transition rate, branching ratio and integrated emission cross section. And Er : YVO4 crystal application value has been analyzed with the optical parameters. Especially there are large oscillator strengths and large integrated emission cross sections in the transitions of 4 I1/2 --> 4 I15/2, 2 H11/2 --> 4I15/2, 4S3/2 --> 4 I15/2, and 4F9/2 --> 4 I15/2. So, they are more worth of attention. Moreover, by comparing the Er-doped yttrium vanadate crystal and other Er-doped crystal optical properties, the authors can see the advantages of YVO4 as laser crystal. Finally, the authors discussed the splitting of the energy levels of Er3+ in the crystal YVO4 based on the group theory.

  16. Transitions of protein traffic from cardiac ER to junctional SR.

    PubMed

    Sleiman, Naama H; McFarland, Timothy P; Jones, Larry R; Cala, Steven E

    2015-04-01

    The junctional sarcoplasmic reticulum (jSR) is an important and unique ER subdomain in the adult myocyte that concentrates resident proteins to regulate Ca(2+) release. To investigate cellular mechanisms for sorting and trafficking proteins to jSR, we overexpressed canine forms of junctin (JCT) or triadin (TRD) in adult rat cardiomyocytes. Protein accumulation over time was visualized by confocal fluorescence microscopy using species-specific antibodies. Newly synthesized JCTdog and TRDdog appeared by 12-24h as bright fluorescent puncta close to the nuclear surface, decreasing in intensity with increasing radial distance. With increasing time (24-48h), fluorescent puncta appeared at further radial distances from the nuclear surface, eventually populating jSR similar to steady-state patterns. CSQ2-DsRed, a form of CSQ that polymerizes ectopically in rough ER, prevented anterograde traffic of newly made TRDdog and JCTdog, demonstrating common pathways of intracellular trafficking as well as in situ binding to CSQ2 in juxtanuclear rough ER. Reversal of CSQ-DsRed interactions occurred when a form of TRDdog was used in which CSQ2-binding sites are removed ((del)TRD). With increasing levels of expression, CSQ2-DsRed revealed a novel smooth ER network that surrounds nuclei and connects the nuclear axis. TRDdog was retained in smooth ER by binding to CSQ2-DsRed, but escaped to populate jSR puncta. TRDdog and (del)TRD were therefore able to elucidate areas of ER-SR transition. High levels of CSQ2-DsRed in the ER led to loss of jSR puncta labeling, suggesting a plasticity of ER-SR transition sites. We propose a model of ER and SR protein traffic along microtubules, with prominent transverse/radial ER trafficking of JCT and TRD along Z-lines to populate jSR, and an abundant longitudinal/axial smooth ER between and encircling myonuclei, from which jSR proteins traffic.

  17. Membrane-bound fatty acid desaturases are inserted co-translationally into the ER and contain different ER retrieval motifs at their carboxy termini.

    PubMed

    McCartney, Andrew W; Dyer, John M; Dhanoa, Preetinder K; Kim, Peter K; Andrews, David W; McNew, James A; Mullen, Robert T

    2004-01-01

    Fatty acid desaturases (FADs) play a prominent role in plant lipid metabolism and are located in various subcellular compartments, including the endoplasmic reticulum (ER). To investigate the biogenesis of ER-localized membrane-bound FADs, we characterized the mechanisms responsible for insertion of Arabidopsis FAD2 and Brassica FAD3 into ER membranes and determined the molecular signals that maintain their ER residency. Using in vitro transcription/translation reactions with ER-derived microsomes, we show that both FAD2 and FAD3 are efficiently integrated into membranes by a co-translational, translocon-mediated pathway. We also demonstrate that while the C-terminus of FAD3 (-KSKIN) contains a functional prototypic dilysine ER retrieval motif, FAD2 contains a novel C-terminal aromatic amino acid-containing sequence (-YNNKL) that is both necessary and sufficient for maintaining localization in the ER. Co-expression of a membrane-bound reporter protein containing the FAD2 C-terminus with a dominant-negative mutant of ADP-ribosylation factor (Arf)1 abolished transient localization of the reporter protein in the Golgi, indicating that the FAD2 peptide signal acts as an ER retrieval motif. Mutational analysis of the FAD2 ER retrieval signal revealed a sequence-specific motif consisting of Phi-X-X-K/R/D/E-Phi-COOH, where -Phi- are large hydrophobic amino acid residues. Interestingly, this aromatic motif was present in a variety of other known and putative ER membrane proteins, including cytochrome P450 and the peroxisomal biogenesis factor Pex10p. Taken together, these data describe the insertion and retrieval mechanisms of FADs and define a new ER localization signal in plants that is responsible for the retrieval of escaped membrane proteins back to the ER.

  18. Loss of Clcc1 Results in ER Stress, Misfolded Protein Accumulation, and Neurodegeneration

    PubMed Central

    Jia, Yichang; Jucius, Thomas J.; Cook, Susan A.

    2015-01-01

    Folding of transmembrane and secretory proteins occurs in the lumen of the endoplasmic reticulum (ER) before transportation to the cell surface and is monitored by the unfolded protein response (UPR) signaling pathway. The accumulation of unfolded proteins in the ER activates the UPR that restores ER homeostasis by regulating gene expression that leads to an increase in the protein-folding capacity of the ER and a decrease in the ER protein-folding load. However, prolonged UPR activity has been associated with cell death in multiple pathological conditions, including neurodegeneration. Here, we report a spontaneous recessive mouse mutation that causes progressive cerebellar granule cell death and peripheral motor axon degeneration. By positional cloning, we identify the mutation in this strain as a retrotransposon insertion in the Clcc1 gene, which encodes a putative chloride channel localized to the ER. Furthermore, we demonstrate that the C3H/HeSnJ inbred strain has late onset cerebellar degeneration due to this mutation. Interestingly, acute knockdown of Clcc1 expression in cultured cells increases sensitivity to ER stress. In agreement, GRP78, the major HSP70 family chaperone in the ER, is upregulated in Clcc1-deficient granule cells in vivo, and ubiquitinated proteins accumulate in these neurons before their degeneration. These data suggest that disruption of chloride homeostasis in the ER disrupts the protein-folding capacity of the ER, leading to eventual neuron death. PMID:25698737

  19. The endogenous caspase-8 inhibitor c-FLIPL regulates ER morphology and crosstalk with mitochondria

    PubMed Central

    Marini, E S; Giampietri, C; Petrungaro, S; Conti, S; Filippini, A; Scorrano, L; Ziparo, E

    2015-01-01

    Components of the death receptor-mediated pathways like caspase-8 have been identified in complexes at intracellular membranes to spatially restrict the processing of local targets. In this study, we report that the long isoform of the cellular FLICE-inhibitory protein (c-FLIPL), a well-known inhibitor of the extrinsic cell death initiator caspase-8, localizes at the endoplasmic reticulum (ER) and mitochondria-associated membranes (MAMs). ER morphology was disrupted and ER Ca2+-release as well as ER-mitochondria tethering was decreased in c-FLIP−/− mouse embryonic fibroblasts (MEFs). Mechanistically, c-FLIP ablation resulted in enhanced basal caspase-8 activation and in caspase-mediated processing of the ER-shaping protein reticulon-4 (RTN4) that was corrected by re-introduction of c-FLIPL and caspase inhibition, resulting in the recovery of a normal ER morphology and ER-mitochondria juxtaposition. Thus, the caspase-8 inhibitor c-FLIPL emerges as a component of the MAMs signaling platforms, where caspases appear to regulate ER morphology and ER-mitochondria crosstalk by impinging on ER-shaping proteins like the RTN4. PMID:25501600

  20. Genome-wide association studies identify four ER negative–specific breast cancer risk loci

    PubMed Central

    Garcia-Closas, Montserrat; Couch, Fergus J; Lindstrom, Sara; Michailidou, Kyriaki; Schmidt, Marjanka K; Brook, Mark N; orr, Nick; Rhie, Suhn Kyong; Riboli, Elio; Feigelson, Heather s; Le Marchand, Loic; Buring, Julie E; Eccles, Diana; Miron, Penelope; Fasching, Peter A; Brauch, Hiltrud; Chang-Claude, Jenny; Carpenter, Jane; Godwin, Andrew K; Nevanlinna, Heli; Giles, Graham G; Cox, Angela; Hopper, John L; Bolla, Manjeet K; Wang, Qin; Dennis, Joe; Dicks, Ed; Howat, Will J; Schoof, Nils; Bojesen, Stig E; Lambrechts, Diether; Broeks, Annegien; Andrulis, Irene L; Guénel, Pascal; Burwinkel, Barbara; Sawyer, Elinor J; Hollestelle, Antoinette; Fletcher, Olivia; Winqvist, Robert; Brenner, Hermann; Mannermaa, Arto; Hamann, Ute; Meindl, Alfons; Lindblom, Annika; Zheng, Wei; Devillee, Peter; Goldberg, Mark S; Lubinski, Jan; Kristensen, Vessela; Swerdlow, Anthony; Anton-Culver, Hoda; Dörk, Thilo; Muir, Kenneth; Matsuo, Keitaro; Wu, Anna H; Radice, Paolo; Teo, Soo Hwang; Shu, Xiao-Ou; Blot, William; Kang, Daehee; Hartman, Mikael; Sangrajrang, Suleeporn; Shen, Chen-Yang; Southey, Melissa C; Park, Daniel J; Hammet, Fleur; Stone, Jennifer; Veer, Laura J Van’t; Rutgers, Emiel J; Lophatananon, Artitaya; Stewart-Brown, Sarah; Siriwanarangsan, Pornthep; Peto, Julian; Schrauder, Michael G; Ekici, Arif B; Beckmann, Matthias W; Silva, Isabel dos Santos; Johnson, Nichola; Warren, Helen; Tomlinson, Ian; Kerin, Michael J; Miller, Nicola; Marme, Federick; Schneeweiss, Andreas; Sohn, Christof; Truong, Therese; Laurent-Puig, Pierre; Kerbrat, Pierre; Nordestgaard, Børge G; Nielsen, Sune F; Flyger, Henrik; Milne, Roger L; Perez, Jose Ignacio Arias; Menéndez, Primitiva; Müller, Heiko; Arndt, Volker; Stegmaier, Christa; Lichtner, Peter; Lochmann, Magdalena; Justenhoven, Christina; Ko, Yon-Dschun; Muranen, Taru A; Aittomäki, Kristiina; Blomqvist, Carl; Greco, Dario; Heikkinen, Tuomas; Ito, Hidemi; Iwata, Hiroji; Yatabe, Yasushi; Antonenkova, Natalia N; Margolin, Sara; Kataja, Vesa; Kosma, Veli-Matti; Hartikainen, Jaana M; Balleine, Rosemary; Tseng, Chiu-Chen; Van Den Berg, David; Stram, Daniel O; Neven, Patrick; Dieudonné, Anne-Sophie; Leunen, Karin; Rudolph, Anja; Nickels, Stefan; Flesch-Janys, Dieter; Peterlongo, Paolo; Peissel, Bernard; Bernard, Loris; Olson, Janet E; Wang, Xianshu; Stevens, Kristen; Severi, Gianluca; Baglietto, Laura; Mclean, Catriona; Coetzee, Gerhard A; Feng, Ye; Henderson, Brian E; Schumacher, Fredrick; Bogdanova, Natalia V; Labrèche, France; Dumont, Martine; Yip, Cheng Har; Taib, Nur Aishah Mohd; Cheng, Ching-Yu; Shrubsole, Martha; Long, Jirong; Pylkäs, Katri; Jukkola-Vuorinen, Arja; Kauppila, Saila; knight, Julia A; Glendon, Gord; Mulligan, Anna Marie; Tollenaar, Robertus A E M; Seynaeve, Caroline M; Kriege, Mieke; Hooning, Maartje J; Van den Ouweland, Ans M W; Van Deurzen, Carolien H M; Lu, Wei; Gao, Yu-Tang; Cai, Hui; Balasubramanian, Sabapathy P; Cross, Simon S; Reed, Malcolm W R; Signorello, Lisa; Cai, Qiuyin; Shah, Mitul; Miao, Hui; Chan, Ching Wan; Chia, Kee Seng; Jakubowska, Anna; Jaworska, Katarzyna; Durda, Katarzyna; Hsiung, Chia-Ni; Wu, Pei-Ei; Yu, Jyh-Cherng; Ashworth, Alan; Jones, Michael; Tessier, Daniel C; González-Neira, Anna; Pita, Guillermo; Alonso, M Rosario; Vincent, Daniel; Bacot, Francois; Ambrosone, Christine B; Bandera, Elisa V; John, Esther M; Chen, Gary K; Hu, Jennifer J; Rodriguez-gil, Jorge L; Bernstein, Leslie; Press, Michael F; Ziegler, Regina G; Millikan, Robert M; Deming-Halverson, Sandra L; Nyante, Sarah; Ingles, Sue A; Waisfisz, Quinten; Tsimiklis, Helen; Makalic, Enes; Schmidt, Daniel; Bui, Minh; Gibson, Lorna; Müller-Myhsok, Bertram; Schmutzler, Rita K; Hein, Rebecca; Dahmen, Norbert; Beckmann, Lars; Aaltonen, Kirsimari; Czene, Kamila; Irwanto, Astrid; Liu, Jianjun; Turnbull, Clare; Rahman, Nazneen; Meijers-Heijboer, Hanne; Uitterlinden, Andre G; Rivadeneira, Fernando; Olswold, Curtis; Slager, Susan; Pilarski, Robert; Ademuyiwa, Foluso; Konstantopoulou, Irene; Martin, Nicholas G; Montgomery, Grant W; Slamon, Dennis J; Rauh, Claudia; Lux, Michael P; Jud, Sebastian M; Bruning, Thomas; Weaver, Joellen; Sharma, Priyanka; Pathak, Harsh; Tapper, Will; Gerty, Sue; Durcan, Lorraine; Trichopoulos, Dimitrios; Tumino, Rosario; Peeters, Petra H; Kaaks, Rudolf; Campa, Daniele; Canzian, Federico; Weiderpass, Elisabete; Johansson, Mattias; Khaw, Kay-Tee; Travis, Ruth; Clavel-Chapelon, Françoise; Kolonel, Laurence N; Chen, Constance; Beck, Andy; Hankinson, Susan E; Berg, Christine D; Hoover, Robert N; Lissowska, Jolanta; Figueroa, Jonine D; Chasman, Daniel I; Gaudet, Mia M; Diver, W Ryan; Willett, Walter C; Hunter, David J; Simard, Jacques; Benitez, Javier; Dunning, Alison M; Sherman, Mark E; Chenevix-Trench, Georgia; Chanock, Stephen J; Hall, Per; Pharoah, Paul D P; Vachon, Celine; Easton, Douglas F; Haiman, Christopher A; Kraft, Peter

    2013-01-01

    Estrogen receptor (ER)-negative tumors represent 20–30% of all breast cancers, with a higher proportion occurring in younger women and women of African ancestry1. The etiology2 and clinical behavior3 of ER-negative tumors are different from those of tumors expressing ER (ER positive), including differences in genetic predisposition4. To identify susceptibility loci specific to ER-negative disease, we combined in a meta-analysis 3 genome-wide association studies of 4,193 ER-negative breast cancer cases and 35,194 controls with a series of 40 follow-up studies (6,514 cases and 41,455 controls), genotyped using a custom Illumina array, iCOGS, developed by the Collaborative Oncological Gene-environment Study (COGS). SNPs at four loci, 1q32.1 (MDM4, P = 2.1 × 10−12 and LGR6, P = 1.4 × 10−8), 2p24.1 (P = 4.6 × 10−8) and 16q12.2 (FTO, P = 4.0 × 10−8), were associated with ER-negative but not ER-positive breast cancer (P > 0.05). These findings provide further evidence for distinct etiological pathways associated with invasive ER-positive and ER-negative breast cancers. PMID:23535733

  1. Genome-wide association studies identify four ER negative-specific breast cancer risk loci.

    PubMed

    Garcia-Closas, Montserrat; Couch, Fergus J; Lindstrom, Sara; Michailidou, Kyriaki; Schmidt, Marjanka K; Brook, Mark N; Orr, Nick; Rhie, Suhn Kyong; Riboli, Elio; Feigelson, Heather S; Le Marchand, Loic; Buring, Julie E; Eccles, Diana; Miron, Penelope; Fasching, Peter A; Brauch, Hiltrud; Chang-Claude, Jenny; Carpenter, Jane; Godwin, Andrew K; Nevanlinna, Heli; Giles, Graham G; Cox, Angela; Hopper, John L; Bolla, Manjeet K; Wang, Qin; Dennis, Joe; Dicks, Ed; Howat, Will J; Schoof, Nils; Bojesen, Stig E; Lambrechts, Diether; Broeks, Annegien; Andrulis, Irene L; Guénel, Pascal; Burwinkel, Barbara; Sawyer, Elinor J; Hollestelle, Antoinette; Fletcher, Olivia; Winqvist, Robert; Brenner, Hermann; Mannermaa, Arto; Hamann, Ute; Meindl, Alfons; Lindblom, Annika; Zheng, Wei; Devillee, Peter; Goldberg, Mark S; Lubinski, Jan; Kristensen, Vessela; Swerdlow, Anthony; Anton-Culver, Hoda; Dörk, Thilo; Muir, Kenneth; Matsuo, Keitaro; Wu, Anna H; Radice, Paolo; Teo, Soo Hwang; Shu, Xiao-Ou; Blot, William; Kang, Daehee; Hartman, Mikael; Sangrajrang, Suleeporn; Shen, Chen-Yang; Southey, Melissa C; Park, Daniel J; Hammet, Fleur; Stone, Jennifer; Veer, Laura J Van't; Rutgers, Emiel J; Lophatananon, Artitaya; Stewart-Brown, Sarah; Siriwanarangsan, Pornthep; Peto, Julian; Schrauder, Michael G; Ekici, Arif B; Beckmann, Matthias W; Dos Santos Silva, Isabel; Johnson, Nichola; Warren, Helen; Tomlinson, Ian; Kerin, Michael J; Miller, Nicola; Marme, Federick; Schneeweiss, Andreas; Sohn, Christof; Truong, Therese; Laurent-Puig, Pierre; Kerbrat, Pierre; Nordestgaard, Børge G; Nielsen, Sune F; Flyger, Henrik; Milne, Roger L; Perez, Jose Ignacio Arias; Menéndez, Primitiva; Müller, Heiko; Arndt, Volker; Stegmaier, Christa; Lichtner, Peter; Lochmann, Magdalena; Justenhoven, Christina; Ko, Yon-Dschun; Muranen, Taru A; Aittomäki, Kristiina; Blomqvist, Carl; Greco, Dario; Heikkinen, Tuomas; Ito, Hidemi; Iwata, Hiroji; Yatabe, Yasushi; Antonenkova, Natalia N; Margolin, Sara; Kataja, Vesa; Kosma, Veli-Matti; Hartikainen, Jaana M; Balleine, Rosemary; Tseng, Chiu-Chen; Berg, David Van Den; Stram, Daniel O; Neven, Patrick; Dieudonné, Anne-Sophie; Leunen, Karin; Rudolph, Anja; Nickels, Stefan; Flesch-Janys, Dieter; Peterlongo, Paolo; Peissel, Bernard; Bernard, Loris; Olson, Janet E; Wang, Xianshu; Stevens, Kristen; Severi, Gianluca; Baglietto, Laura; McLean, Catriona; Coetzee, Gerhard A; Feng, Ye; Henderson, Brian E; Schumacher, Fredrick; Bogdanova, Natalia V; Labrèche, France; Dumont, Martine; Yip, Cheng Har; Taib, Nur Aishah Mohd; Cheng, Ching-Yu; Shrubsole, Martha; Long, Jirong; Pylkäs, Katri; Jukkola-Vuorinen, Arja; Kauppila, Saila; Knight, Julia A; Glendon, Gord; Mulligan, Anna Marie; Tollenaar, Robertus A E M; Seynaeve, Caroline M; Kriege, Mieke; Hooning, Maartje J; van den Ouweland, Ans M W; van Deurzen, Carolien H M; Lu, Wei; Gao, Yu-Tang; Cai, Hui; Balasubramanian, Sabapathy P; Cross, Simon S; Reed, Malcolm W R; Signorello, Lisa; Cai, Qiuyin; Shah, Mitul; Miao, Hui; Chan, Ching Wan; Chia, Kee Seng; Jakubowska, Anna; Jaworska, Katarzyna; Durda, Katarzyna; Hsiung, Chia-Ni; Wu, Pei-Ei; Yu, Jyh-Cherng; Ashworth, Alan; Jones, Michael; Tessier, Daniel C; González-Neira, Anna; Pita, Guillermo; Alonso, M Rosario; Vincent, Daniel; Bacot, Francois; Ambrosone, Christine B; Bandera, Elisa V; John, Esther M; Chen, Gary K; Hu, Jennifer J; Rodriguez-Gil, Jorge L; Bernstein, Leslie; Press, Michael F; Ziegler, Regina G; Millikan, Robert M; Deming-Halverson, Sandra L; Nyante, Sarah; Ingles, Sue A; Waisfisz, Quinten; Tsimiklis, Helen; Makalic, Enes; Schmidt, Daniel; Bui, Minh; Gibson, Lorna; Müller-Myhsok, Bertram; Schmutzler, Rita K; Hein, Rebecca; Dahmen, Norbert; Beckmann, Lars; Aaltonen, Kirsimari; Czene, Kamila; Irwanto, Astrid; Liu, Jianjun; Turnbull, Clare; Rahman, Nazneen; Meijers-Heijboer, Hanne; Uitterlinden, Andre G; Rivadeneira, Fernando; Olswold, Curtis; Slager, Susan; Pilarski, Robert; Ademuyiwa, Foluso; Konstantopoulou, Irene; Martin, Nicholas G; Montgomery, Grant W; Slamon, Dennis J; Rauh, Claudia; Lux, Michael P; Jud, Sebastian M; Bruning, Thomas; Weaver, Joellen; Sharma, Priyanka; Pathak, Harsh; Tapper, Will; Gerty, Sue; Durcan, Lorraine; Trichopoulos, Dimitrios; Tumino, Rosario; Peeters, Petra H; Kaaks, Rudolf; Campa, Daniele; Canzian, Federico; Weiderpass, Elisabete; Johansson, Mattias; Khaw, Kay-Tee; Travis, Ruth; Clavel-Chapelon, Françoise; Kolonel, Laurence N; Chen, Constance; Beck, Andy; Hankinson, Susan E; Berg, Christine D; Hoover, Robert N; Lissowska, Jolanta; Figueroa, Jonine D; Chasman, Daniel I; Gaudet, Mia M; Diver, W Ryan; Willett, Walter C; Hunter, David J; Simard, Jacques; Benitez, Javier; Dunning, Alison M; Sherman, Mark E; Chenevix-Trench, Georgia; Chanock, Stephen J; Hall, Per; Pharoah, Paul D P; Vachon, Celine; Easton, Douglas F; Haiman, Christopher A; Kraft, Peter

    2013-04-01

    Estrogen receptor (ER)-negative tumors represent 20-30% of all breast cancers, with a higher proportion occurring in younger women and women of African ancestry. The etiology and clinical behavior of ER-negative tumors are different from those of tumors expressing ER (ER positive), including differences in genetic predisposition. To identify susceptibility loci specific to ER-negative disease, we combined in a meta-analysis 3 genome-wide association studies of 4,193 ER-negative breast cancer cases and 35,194 controls with a series of 40 follow-up studies (6,514 cases and 41,455 controls), genotyped using a custom Illumina array, iCOGS, developed by the Collaborative Oncological Gene-environment Study (COGS). SNPs at four loci, 1q32.1 (MDM4, P = 2.1 × 10(-12) and LGR6, P = 1.4 × 10(-8)), 2p24.1 (P = 4.6 × 10(-8)) and 16q12.2 (FTO, P = 4.0 × 10(-8)), were associated with ER-negative but not ER-positive breast cancer (P > 0.05). These findings provide further evidence for distinct etiological pathways associated with invasive ER-positive and ER-negative breast cancers.

  2. Photothermal treatment of liver cancer with albumin-conjugated gold nanoparticles initiates Golgi Apparatus-ER dysfunction and caspase-3 apoptotic pathway activation by selective targeting of Gp60 receptor.

    PubMed

    Mocan, Lucian; Matea, Cristian; Tabaran, Flaviu A; Mosteanu, Ofelia; Pop, Teodora; Mocan, Teodora; Iancu, Cornel

    2015-01-01

    We present a method of enhanced laser thermal ablation of HepG2 cells based on a simple gold nanoparticle (GNP) carrier system such as serum albumin (Alb), and demonstrate its selective therapeutic efficacy compared with normal hepatocyte cells. HepG2 or hepatocytes were treated with Alb-GNPs at various concentrations and various incubation times, and further irradiated using a 2 W, 808 nm laser. Darkfield microscopy and immunochemical staining was used to demonstrate the selective internalization of Alb-GNPs inside the HepG2 cells via Gp60 receptors targeting. The postirradiation apoptotic rate of HepG2 cells treated with Alb-GNPs ranged from 25.8% (for 5 μg/mL) to 48.2% (for 50 μg/mL) at 60 seconds, while at 30 minutes the necrotic rate increased from 35.7% (5 μg/mL) to 52.3% (50 μg/mL), P-value <0.001. Significantly lower necrotic rates were obtained when human hepatocytes were treated with Alb-GNPs in a similar manner. We also showed by means of immunocytochemistry that photothermal treatment of Alb-conjugated GNPs in liver cancer initiates Golgi apparatus-endoplasmic reticulum dysfunction with consequent caspase-3 apoptotic pathway activation and cellular apoptosis. The presented results may become a new method of treating cancer cells by selective therapeutic vectors using nanolocalized thermal ablation by laser heating.

  3. Rafting with cholera toxin: endocytosis and trafficking from plasma membrane to ER.

    PubMed

    Chinnapen, Daniel J-F; Chinnapen, Himani; Saslowsky, David; Lencer, Wayne I

    2007-01-01

    Cholera toxin (CT), and members of the AB(5) family of toxins enter host cells and hijack the cell's endogenous pathways to induce toxicity. CT binds to a lipid receptor on the plasma membrane (PM), ganglioside GM1, which has the ability to associate with lipid rafts. The toxin can then enter the cell by various modes of receptor-mediated endocytosis and traffic in a retrograde manner from the PM to the Golgi and the endoplasmic reticulum (ER). Once in the ER, a portion of the toxin is unfolded and retro-translocated to the cytosol so as to induce disease. GM1 is the vehicle that carries CT from PM to ER. Thus, the toxin pathway from PM to ER is a lipid-based sorting pathway, which is potentially meditated by the determinants of the GM1 ganglioside structure itself.

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

    PubMed

    Binet, François; Chiasson, Sonia; Girard, Denis

    2010-01-01

    Apoptosis can result from activation of three major pathways: the extrinsic, the intrinsic, and the most recently identified endoplasmic reticulum (ER) stress-mediated pathway. While the two former pathways are known to be operational in human polymorphonuclear neutrophils (PMNs), the existence of the ER stress-mediated pathway, generally involving caspase-4, has never been reported in these cells. Recently, we have documented that arsenic trioxide (ATO) induced apoptosis in human PMNs by a mechanism that needs to be further investigated. In this study, using immunofluorescence and electron microscopy, we present evidence of ER alterations in PMNs activated by the ER stress inducer arsenic trioxide (ATO). Several key players of the unfolded protein response, including GRP78, GADD153, ATF6, XBP1 and eIF2alpha are expressed and activated in PMNs treated with ATO or other ER stress inducers. Although caspase-4 is expressed and activated in neutrophils, treatment with a caspase-4 inhibitor did not attenuate the pro-apoptotic effect of ATO at a concentration that reverses caspase-4 processing and activation. Our results demonstrate for the first time that the ER stress-mediated apoptotic pathway operates in human neutrophils.

  5. ER Ca2+ depletion triggers apoptotic signals for endoplasmic reticulum (ER) overload response induced by overexpressed reticulon 3 (RTN3/HAP).

    PubMed

    Kuang, Ersheng; Wan, Qingwen; Li, Xiaojuan; Xu, Hua; Liu, Qingzhen; Qi, Yipeng

    2005-08-01

    Perturbance of endoplasmic reticulum (ER) function, either by the mutant proteins not folding correctly, or by an excessive accumulation of proteins in the organelle, will lead to the unfolded protein response (UPR) or ER overload response (EOR). The signal-transducing pathways for UPR have been identified, whereas the pathway for EOR remains to be elucidated. Our previous study demonstrated that the overexpression of reticulon 3 (RTN3, also named HAP, homologue of ASY protein) caused apoptosis with the depletion of ER Ca(2+) stores. In present research, we characterized RTN3 as a novel EOR-induced protein, triggering the apoptotic signals through the release of ER Ca(2+) and the elevation of cytosolic Ca(2+). Our studies showed that overexpressed RTN3 induced EOR, eliciting ER-specific apoptosis with activation of caspase-12 and mitochondrial dysfunction through ER Ca(2+) depletion and the sustained elevation of cytosolic Ca(2+). Furthermore, we demonstrated that overexpressed RTN3 and stimuli that activate both EOR and UPR, not UPR only, were able to induce up-regulation of inducible nitric oxide synthase (iNOS) in HeLa cells through ER Ca(2+) release and reactive oxygen intermediates (ROIs), resulting in endogenous calcium-dependent nitric oxide protecting cells against ER specific apoptosis, which suggested that the nitric oxide and iNOS represented a likely protective response to EOR, not the UPR. These results supported that the release of ER Ca(2+) stores triggered the initial signal-transducing pathways for EOR induced by overexpressed RTN3.

  6. The Effectiveness of Core ER Principles

    ERIC Educational Resources Information Center

    Jeon, Eun-Young; Day, Richard R.

    2015-01-01

    This discussion piece continues the discussion forum on extensive reading (ER) from the April 2015 issue of "Reading in a Foreign Language." In that forum, a number of the discussions were concerned with the principles of ER (Day & Bamford, 2002) in implementing ER. Our discussion also concerns the principles; we examine ER programs…

  7. Coordination of Endoplasmic Reticulum (ER) Signaling During Maize Seed Development

    SciTech Connect

    Boston, Rebecca S.

    2010-11-20

    Seed storage reserves represent one of the most important sources of renewable fixed carbon and nitrogen found in nature. Seeds are well-adapted for diverting metabolic resources to synthesize storage proteins as well as enzymes and structural proteins needed for their transport and packaging into membrane bound storage protein bodies. Our underlying hypothesis is that the endoplasmic reticulum (ER) stress response provides the critical cellular control of metabolic flux required for optimal accumulation of storage reserves in seeds. This highly conserved response is a cellular mechanism to monitor the protein folding environment of the ER and restore homeostasis in the presence of unfolded or misfolded proteins. In seeds, deposition of storage proteins in protein bodies is a highly specialized process that takes place even in the presence of mutant proteins that no longer fold and package properly. The capacity of the ER to deposit these aberrant proteins in protein bodies during a period that extends several weeks provides an excellent model for deconvoluting the ER stress response of plants. We have focused in this project on the means by which the ER senses and responds to functional perturbations and the underlying intracellular communication that occurs among biosynthetic, trafficking and degradative pathways for proteins during seed development.

  8. Apoptosis/Necrosis Induction by Ultraviolet, in ER Positive and ER Negative Breast Cancer Cell Lines

    PubMed Central

    Shokrollahi Barough, Mahdieh; Hasanzadeh, Hadi; Barati, Mehdi; Pak, Fatemeh; Kokhaei, Parviz; Rezaei-Tavirani, Mostafa

    2015-01-01

    Background: Ultraviolet (UV) light exposure has been one of the major inducers of apoptosis. UV exposure has caused pyrimidine dimers and DNA fragmentation which might lead to cell cycle arrest and apoptosis signals activation. UV induced apoptosis has investigated in MDA-MB 468 as an ER negative breast adenocarcinoma and MCF-7 as an ER positive breast cancer cell line. Apoptosis induction rate by UV might be different in these two types of cells due to different biological characteristics of the cell. Objectives: In this paper we have evaluated serial dose of UV-B exposure on ER positive and ER negative breast cancer cell lines and its effect on apoptosis or necrosis induction in these cells. Materials and Methods: MDA-MB468 and MCF-7 cell lines have cultured for 24 hours and UV exposure has carried out at 290 nm at dose of 154 J/m2 to 18 KJ/m2 using UV lamp. UV exposed cells have incubated in cell culture condition for 24 or 48 hours following UV exposure and the cells have stained and analyzed by flow cytometry for apoptosis evaluation by Annexin V/PI method. Results: Apoptosis rate (PI and Annexin V double positive cells) after 24 hours incubation was higher in 24 hours in comparison with 48 hours incubation in both cell lines. The frequency of PI positive MDA-MB 468 cells was higher than PI and Annexin V double positive cells after 48 hours. PI positive MDA-MB 468 cells were significantly higher than MCF-7 cells in 24 hours incubation time. Conclusions: The results have shown that MDA-MB 468 cells were more sensitive to UV exposure and DNA fragmentation and necrosis pathway was dominant in these cells. PMID:26855725

  9. Ames ER-2 ozone measurements

    NASA Technical Reports Server (NTRS)

    Pearson, R., Jr.; Vedder, James F.; Starr, W. L.

    1990-01-01

    The objective of this research is to study ozone (O3) in the stratosphere. Measurements of the ozone mixing ratio at 1 s intervals are obtained with an ultraviolet photometer which flies on the ER-2 aircraft. The photometer determines the amount of ozone in air by measuring the transmission of ultraviolet light through a fixed path with and without ambient O3 present.

  10. ERS-1 SAR data processing

    NASA Technical Reports Server (NTRS)

    Leung, K.; Bicknell, T.; Vines, K.

    1986-01-01

    To take full advantage of the synthetic aperature radar (SAR) to be flown on board the European Space Agency's Remote Sensing Satellite (ERS-1) (1989) and the Canadian Radarsat (1990), the implementation of a receiving station in Alaska is being studied to gather and process SAR data pertaining in particular to regions within the station's range of reception. The current SAR data processing requirement is estimated to be on the order of 5 minutes per day. The Interim Digital Sar Processor (IDP) which was under continual development through Seasat (1978) and SIR-B (1984) can process slightly more than 2 minutes of ERS-1 data per day. On the other hand, the Advanced Digital SAR Processore (ADSP), currently under development for the Shuttle Imaging Radar C (SIR-C, 1988) and the Venus Radar Mapper, (VMR, 1988), is capable of processing ERS-1 SAR data at a real time rate. To better suit the anticipated ERS-1 SAR data processing requirement, both a modified IDP and an ADSP derivative are being examined. For the modified IDP, a pipelined architecture is proposed for the mini-computer plus array processor arrangement to improve throughout. For the ADSP derivative, a simplified version is proposed to enhance ease of implementation and maintainability while maintaing real time throughput rates. These processing systems are discussed and evaluated.

  11. Nonmuscle Myosin IIB Links Cytoskeleton to IRE1α Signaling during ER Stress

    PubMed Central

    He, Yin; Beatty, Alexander; Han, Xuemei; Ji, Yewei; Ma, Xuefei; Adelstein, Robert S.; Yates, John R.; Kemphues, Kenneth; Qi, Ling

    2013-01-01

    SUMMARY Here we identify and characterize a cytoskeletal myosin protein required for IRE1α oligomerization, activation, and signaling. Proteomic screening identified nonmuscle myosin heavy chain IIB (NMHCIIB), a subunit of nonmuscle myosin IIB (NMIIB), as an ER stress-dependent interacting protein specific to IRE1α. Loss of NMIIB compromises XBP1s and UPR target gene expression with no effect on the PERK pathway. Mechanistically, NMIIB is required for IRE1α aggregation and foci formation under ER stress. The NMIIB-mediated effect on IRE1α signaling is in part dependent on the phosphorylation of myosin regulatory light chain and the actomyosin contractility of NMIIB. Biologically, the function of NMIIB in ER stress response is conserved as both mammalian cells and C. elegans lacking NMIIB exhibit hypersensitivity to ER stress. Thus, optimal IRE1α activation and signaling require concerted coordination between the ER and cytoskeleton. PMID:23237951

  12. Atlastin GTPases are required for Golgi apparatus and ER morphogenesis.

    PubMed

    Rismanchi, Neggy; Soderblom, Cynthia; Stadler, Julia; Zhu, Peng-Peng; Blackstone, Craig

    2008-06-01

    The hereditary spastic paraplegias (SPG1-33) comprise a cluster of inherited neurological disorders characterized principally by lower extremity spasticity and weakness due to a length-dependent, retrograde axonopathy of corticospinal motor neurons. Mutations in the gene encoding the large oligomeric GTPase atlastin-1 are responsible for SPG3A, a common autosomal dominant hereditary spastic paraplegia. Here we describe a family of human GTPases, atlastin-2 and -3 that are closely related to atlastin-1. Interestingly, while atlastin-1 is predominantly localized to vesicular tubular complexes and cis-Golgi cisternae, mostly in brain, atlastin-2 and -3 are localized to the endoplasmic reticulum (ER) and are most enriched in other tissues. Knockdown of atlastin-2 and -3 levels in HeLa cells using siRNA (small interfering RNA) causes disruption of Golgi morphology, and these Golgi structures remain sensitive to brefeldin A treatment. Interestingly, expression of SPG3A mutant or dominant-negative atlastin proteins lacking GTPase activity causes prominent inhibition of ER reticularization, suggesting a role for atlastin GTPases in the formation of three-way junctions in the ER. However, secretory pathway trafficking as assessed using vesicular stomatitis virus G protein fused to green fluorescent protein (VSVG-GFP) as a reporter was essentially normal in both knockdown and dominant-negative overexpression conditions for all atlastins. Thus, the atlastin family of GTPases functions prominently in both ER and Golgi morphogenesis, but they do not appear to be required generally for anterograde ER-to-Golgi trafficking. Abnormal morphogenesis of the ER and Golgi resulting from mutations in atlastin-1 may ultimately underlie SPG3A by interfering with proper membrane distribution or polarity of the long corticospinal motor neurons.

  13. Endoplasmic Reticulum (ER) Stress and Endocrine Disorders

    PubMed Central

    Ariyasu, Daisuke; Yoshida, Hiderou; Hasegawa, Yukihiro

    2017-01-01

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

  14. Completion report for Well Cluster ER-20-6

    SciTech Connect

    1998-02-01

    The Well Cluster ER-20-6 drilling and completion project was conducted during February, March, and April of 1996 in support of the Nevada Environmental Restoration Project at the Nevada Test Site (NTS), Nye County, Nevada. This project is part of the DOE`s Underground Test Area (UGTA) subproject at the NTS. The primary UGTA tasks include collecting geological, geophysical, and hydrological data from new and existing wells to define groundwater quality as well as pathways and rates of groundwater migration at the NTS. A program of drilling wells near the sites of selected underground nuclear tests (near-field drilling) was implemented as part of the UGTA subproject to obtain site-specific data on the nature and extent of migration of radionuclides produced by an underground nuclear explosion. The ER-20-6 near-field drilling project was originally planned to be very similar to that recently conducted at Well Cluster ER-20-5, which was designed to obtain data on the existing hydrologic regime near the site of an underground nuclear explosion (IT, 1995; IT, 1996a). However, after further consideration of the goals of the near-field drilling program and the characteristics of the BULLION site, the TWG recommended that the ER-20-6 project be redesigned to accommodate a forced-gradient experiment. This proposed experiment is expected to yield more realistic estimates of transport parameters than can be deduced from sampling and testing natural groundwater flow systems.

  15. Tank 241-ER-311, grab samples, ER311-98-1, ER311-98-2, ER311-98-3 analytical results for the final report

    SciTech Connect

    FULLER, R.K.

    1999-02-24

    This document is the final report for catch tank 241-ER-311 grab samples. Three grab samples ER311-98-1, ER311-98-2 and ER311-98-3 were taken from East riser of tank 241-ER-311 on August 4, 1998 and received by the 222-S Laboratory on August 4, 1998. Analyses were performed in accordance with the Compatibility Grab Sampling and Analysis Plan (TSAP) (Sasaki, 1998)and the Data Quality Objectives for Tank Farms Waste Compatibility Program (DQO) (Mulkey and Miller, 1997). The analytical results are presented in the data summary report (Table 1). No notification limits were exceeded.

  16. NASA ER-2: Flying Laboratory for Earth Science Studies

    NASA Technical Reports Server (NTRS)

    Navarro, Robert

    2007-01-01

    This viewgraph presentation gives an overview of the NASA ER-2 aircraft. The contents include: 1) ER-2 Specifications; 2) ER-2 Basic Configuration; 3) ER-2 Payload Areas: Nose Area; 4) ER-2 Payload Areas: SuperPod Fore and Aftbody; 5) ER-2 Payload Areas: SuperPod Midbody; 6) ER-2 Payload Areas: Q-Bay; 7) ER-2 Payload Areas: Q-Bay Hatch Designs; 8) ER-2 Payload Areas: External Pods; 9) ER-2 Electrical/Control Interface; 10) ER-2 Typical Flight Profile; 11) Tropical Composition, Cloud and Climate Coupling TC-4; 12) TC-4 Timeline; 13) TC4 Area of Interest; 14) ER-2 TC4 Payload; 15) A/C ready for fuel; 16) ER-2 Pilot being suited; 17) ER-2 Taxing; 18) ER-2 Pilot post flight debrief; and 19) NASA ER-2: Flying Laboratory for Earth Science Studies and Remote Sensing.

  17. Mitochondria-Associated Membranes and ER Stress.

    PubMed

    van Vliet, Alexander R; Agostinis, Patrizia

    2017-03-28

    The endoplasmic reticulum (ER) is a crucial organelle for coordinating cellular Ca(2+) signaling and protein synthesis and folding. Moreover, the dynamic and complex membranous structures constituting the ER allow the formation of contact sites with other organelles and structures, including among others the mitochondria and the plasma membrane (PM). The contact sites that the ER form with mitochondria is a hot topic in research, and the nature of the so-called mitochondria-associated membranes (MAMs) is continuously evolving. The MAMs consist of a proteinaceous tether that physically connects the ER with mitochondria. The MAMs harness the main functions of both organelles to form a specialized subcompartment at the interface of the ER and mitochondria. Under homeostatic conditions, MAMs are crucial for the efficient transfer of Ca(2+) from the ER to mitochondria, and for proper mitochondria bioenergetics and lipid synthesis. MAMs are also believed to be the master regulators of mitochondrial shape and motility, and to form a crucial site for autophagosome assembly. Not surprisingly, MAMs have been shown to be a hot spot for the transfer of stress signals from the ER to mitochondria, most notably under the conditions of loss of ER proteostasis, by engaging the unfolded protein response (UPR). In this chapter after an introduction on ER biology and ER stress, we will review the emerging and key signaling roles of the MAMs, which have a root in cellular processes and signaling cascades coordinated by the ER.

  18. Estrogen Receptor (ER)-α36 Is Involved in Estrogen- and Tamoxifen-Induced Neuroprotective Effects in Ischemic Stroke Models

    PubMed Central

    Fang, Chen; Ji, Xiaofei; Liang, Xiaofeng; Liu, Yang; Han, Chao; Huang, Liang; Zhang, Qiqi; Li, Hongyan; Zhang, Yejun; Liu, Jinqiu

    2015-01-01

    The neuroprotection by estrogen (E2) and tamoxifen is well documented in experimental stroke models; however, the exact mechanism is unclear. A membrane-based estrogen receptor, ER-α36, has been identified. Postmenopausal-levels of E2 act through ER-α36 to induce osteoclast apoptosis due to a prolonged activation of the mitogen-activated protein kinase (MAPK)/extracellular signal-related kinase (ERK) signaling. We hypothesized that ER-α36 may play a role in the neuroprotective activities of estrogen and tamoxifen. Here, we studied ER-α36 expression in the brain, as well as its neuroprotective effects against oxygen and glucose deprivation (OGD) in PC12 cells. We found that ER-α36 was expressed in both rat and human brain. In addition, OGD-induced cell death was prevented by l nmol/L 17β-estradiol (E2β). E2β activates the MAPK/ERK signaling pathway in PC12 cells under basal and OGD conditions by interacting with ER-α36 and also induces ER-α36 expression. Low-dose of tamoxifen up-regulated ER-α36 expression and enhanced neuronal survival in an ovariectomized ischemic stroke model. Furthermore, low-dose of tamoxifen enhanced neuroprotective effects by modulating activates or suppress ER-α36. Our results thus demonstrated that ER-α36 is involved in neuroprotective activities mediated by both estrogen and tamoxifen. PMID:26484775

  19. PUMA mediates ER stress-induced apoptosis in portal hypertensive gastropathy.

    PubMed

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

    2014-03-13

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

  20. The Aggregation-Prone Intracellular Serpin SRP-2 Fails to Transit the ER in Caenorhabditis elegans

    PubMed Central

    Silverman, Richard M.; Cummings, Erin E.; O’Reilly, Linda P.; Miedel, Mark T.; Silverman, Gary A.; Luke, Cliff J.; Perlmutter, David H.; Pak, Stephen C.

    2015-01-01

    Familial encephalopathy with neuroserpin inclusions bodies (FENIB) is a serpinopathy that induces a rare form of presenile dementia. Neuroserpin contains a classical signal peptide and like all extracellular serine proteinase inhibitors (serpins) is secreted via the endoplasmic reticulum (ER)–Golgi pathway. The disease phenotype is due to gain-of-function missense mutations that cause neuroserpin to misfold and aggregate within the ER. In a previous study, nematodes expressing a homologous mutation in the endogenous Caenorhabditis elegans serpin, srp-2, were reported to model the ER proteotoxicity induced by an allele of mutant neuroserpin. Our results suggest that SRP-2 lacks a classical N-terminal signal peptide and is a member of the intracellular serpin family. Using confocal imaging and an ER colocalization marker, we confirmed that GFP-tagged wild-type SRP-2 localized to the cytosol and not the ER. Similarly, the aggregation-prone SRP-2 mutant formed intracellular inclusions that localized to the cytosol. Interestingly, wild-type SRP-2, targeted to the ER by fusion to a cleavable N-terminal signal peptide, failed to be secreted and accumulated within the ER lumen. This ER retention phenotype is typical of other obligate intracellular serpins forced to translocate across the ER membrane. Neuroserpin is a secreted protein that inhibits trypsin-like proteinase. SRP-2 is a cytosolic serpin that inhibits lysosomal cysteine peptidases. We concluded that SRP-2 is neither an ortholog nor a functional homolog of neuroserpin. Furthermore, animals expressing an aggregation-prone mutation in SRP-2 do not model the ER proteotoxicity associated with FENIB. PMID:25786854

  1. Stress Signal Network between Hypoxia and ER Stress in Chronic Kidney Disease

    PubMed Central

    Maekawa, Hiroshi; Inagi, Reiko

    2017-01-01

    Chronic kidney disease (CKD) is characterized by an irreversible decrease in kidney function and induction of various metabolic dysfunctions. Accumulated findings reveal that chronic hypoxic stress and endoplasmic reticulum (ER) stress are involved in a range of pathogenic conditions, including the progression of CKD. Because of the presence of an arteriovenous oxygen shunt, the kidney is thought to be susceptible to hypoxia. Chronic kidney hypoxia is induced by a number of pathogenic conditions, including renal ischemia, reduced peritubular capillary, and tubulointerstitial fibrosis. The ER is an organelle which helps maintain the quality of proteins through the unfolded protein response (UPR) pathway, and ER dysfunction associated with maladaptive UPR activation is named ER stress. ER stress is reported to be related to some of the effects of pathogenesis in kidney, particularly in the podocyte slit diaphragm and tubulointerstitium. Furthermore, chronic hypoxia mediates ER stress in blood vessel endothelial cells and tubulointerstitium via several mechanisms, including oxidative stress, epigenetic alteration, lipid metabolism, and the AKT pathway. In summary, a growing consensus considers that these stresses interact via complicated stress signal networks, which leads to the exacerbation of CKD (Figure 1). This stress signal network might be a target for interventions aimed at ameliorating CKD. PMID:28228736

  2. Stress Signal Network between Hypoxia and ER Stress in Chronic Kidney Disease.

    PubMed

    Maekawa, Hiroshi; Inagi, Reiko

    2017-01-01

    Chronic kidney disease (CKD) is characterized by an irreversible decrease in kidney function and induction of various metabolic dysfunctions. Accumulated findings reveal that chronic hypoxic stress and endoplasmic reticulum (ER) stress are involved in a range of pathogenic conditions, including the progression of CKD. Because of the presence of an arteriovenous oxygen shunt, the kidney is thought to be susceptible to hypoxia. Chronic kidney hypoxia is induced by a number of pathogenic conditions, including renal ischemia, reduced peritubular capillary, and tubulointerstitial fibrosis. The ER is an organelle which helps maintain the quality of proteins through the unfolded protein response (UPR) pathway, and ER dysfunction associated with maladaptive UPR activation is named ER stress. ER stress is reported to be related to some of the effects of pathogenesis in kidney, particularly in the podocyte slit diaphragm and tubulointerstitium. Furthermore, chronic hypoxia mediates ER stress in blood vessel endothelial cells and tubulointerstitium via several mechanisms, including oxidative stress, epigenetic alteration, lipid metabolism, and the AKT pathway. In summary, a growing consensus considers that these stresses interact via complicated stress signal networks, which leads to the exacerbation of CKD (Figure 1). This stress signal network might be a target for interventions aimed at ameliorating CKD.

  3. Electronic state of Er in sputtered AlN:Er films determined by magnetic measurements

    SciTech Connect

    Narang, V.; Seehra, M. S.; Korakakis, D.

    2014-12-07

    The optoelectronic and piezoelectric properties of AlN:Er thin films have been of great recent interest for potential device applications. In this work, the focus is on the electronic state of Er in AlN:Er thin films prepared by reactive magnetron sputtering on (001) p-type Si substrate. X-ray diffraction shows that Er doping expands the lattice and the AlN:Er film has preferential c-plane orientation. To determine whether Er in AlN:Er is present as Er metal, Er{sub 2}O{sub 3}, or Er{sup 3+} substituting for Al{sup 3+}, detailed measurements and analysis of the temperature dependence (2 K–300 K) of the magnetization M at a fixed magnetic field H along with the M vs. H data at 2 K up to H = 90 kOe are presented. The presence of Er{sub 2}O{sub 3} and Er metal is ruled out since their characteristic magnetic transitions are not observed in the AlN:Er sample. Instead, the observed M vs. T and M vs. H variations are consistent with Er present as Er{sup 3+} substituting for Al{sup 3+} in AlN:Er at a concentration x = 1.08% in agreement with x = 0.94% ± 0.20% determined using x-ray photoelectron spectroscopy (XPS). The larger size of Er{sup 3+} vs. Al{sup 3+}explains the observed lattice expansion of AlN:Er.

  4. An endoplasmic reticulum (ER) membrane complex composed of SPFH1 and SPFH2 mediates the ER-associated degradation of inositol 1,4,5-trisphosphate receptors.

    PubMed

    Pearce, Margaret M P; Wormer, Duncan B; Wilkens, Stephan; Wojcikiewicz, Richard J H

    2009-04-17

    How endoplasmic reticulum (ER) proteins that are substrates for the ER-associated degradation (ERAD) pathway are recognized for polyubiquitination and proteasomal degradation is largely unresolved. Inositol 1,4,5-trisphosphate receptors (IP(3)Rs) form tetrameric calcium channels in ER membranes, whose primary role is to control the release of ER calcium stores, but whose levels are also regulated, in an activation-dependent manner, by the ERAD pathway. Here we report that the ER membrane protein SPFH1 and its homolog SPFH2 form a heteromeric approximately 2 MDa complex that binds to IP(3)R tetramers immediately after their activation and is required for their processing. The complex is ring-shaped (diameter approximately 250A(),) and RNA interference-mediated depletion of SPFH1 and SPFH2 blocks IP(3)R polyubiquitination and degradation. We propose that this novel SPFH1/2 complex is a recognition factor that targets IP(3)Rs and perhaps other substrates for ERAD.

  5. Human Peroxin PEX3 Is Co-translationally Integrated into the ER and Exits the ER in Budding Vesicles.

    PubMed

    Mayerhofer, Peter U; Bañó-Polo, Manuel; Mingarro, Ismael; Johnson, Arthur E

    2016-02-01

    The long-standing paradigm that all peroxisomal proteins are imported post-translationally into pre-existing peroxisomes has been challenged by the detection of peroxisomal membrane proteins (PMPs) inside the endoplasmic reticulum (ER). In mammals, the mechanisms of ER entry and exit of PMPs are completely unknown. We show that the human PMP PEX3 inserts co-translationally into the mammalian ER via the Sec61 translocon. Photocrosslinking and fluorescence spectroscopy studies demonstrate that the N-terminal transmembrane segment (TMS) of ribosome-bound PEX3 is recognized by the signal recognition particle (SRP). Binding to SRP is a prerequisite for targeting of the PEX3-containing ribosome•nascent chain complex (RNC) to the translocon, where an ordered multistep pathway integrates the nascent chain into the membrane adjacent to translocon proteins Sec61α and TRAM. This insertion of PEX3 into the ER is physiologically relevant because PEX3 then exits the ER via budding vesicles in an ATP-dependent process. This study identifies early steps in human peroxisomal biogenesis by demonstrating sequential stages of PMP passage through the mammalian ER.

  6. Tauroursodeoxycholic acid reduces ER stress by regulating of Akt-dependent cellular prion protein

    PubMed Central

    Yoon, Yeo Min; Lee, Jun Hee; Yun, Seung Pil; Han, Yong-Seok; Yun, Chul Won; Lee, Hyun Jik; Noh, Hyunjin; Lee, Sei-Jung; Han, Ho Jae; Lee, Sang Hun

    2016-01-01

    Although mesenchymal stem cells (MSCs) are a promising cell source for regenerative medicine, ischemia-induced endoplasmic reticulum (ER) stress induces low MSC engraftment and limits their therapeutic efficacy. To overcome this, we investigated the protective effect of tauroursodeoxycholic acid (TUDCA), a bile acid, on ER stress in MSCs in vitro and in vivo. In ER stress conditions, TUDCA treatment of MSCs reduced the activation of ER stress-associated proteins, including GRP78, PERK, eIF2α, ATF4, IRE1α, JNK, p38, and CHOP. In particular, TUDCA inhibited the dissociation between GRP78 and PERK, resulting in reduced ER stress-mediated cell death. Next, to explore the ER stress protective mechanism induced by TUDCA treatment, TUDCA-mediated cellular prion protein (PrPC) activation was assessed. TUDCA treatment increased PrPC expression, which was regulated by Akt phosphorylation. Manganese-dependent superoxide dismutase (MnSOD) expression also increased significantly in response to signaling through the TUDCA-Akt axis. In a murine hindlimb ischemia model, TUDCA-treated MSC transplantation augmented the blood perfusion ratio, vessel formation, and transplanted cell survival more than untreated MSC transplantation did. Augmented functional recovery following MSC transplantation was blocked by PrPC downregulation. This study is the first to demonstrate that TUDCA protects MSCs against ER stress via Akt-dependent PrPC and Akt-MnSOD pathway. PMID:28004805

  7. Unfolded protein response-induced ERdj3 secretion links ER stress to extracellular proteostasis

    PubMed Central

    Genereux, Joseph C; Qu, Song; Zhou, Minghai; Ryno, Lisa M; Wang, Shiyu; Shoulders, Matthew D; Kaufman, Randal J; Lasmézas, Corinne I; Kelly, Jeffery W; Wiseman, R Luke

    2015-01-01

    The Unfolded Protein Response (UPR) indirectly regulates extracellular proteostasis through transcriptional remodeling of endoplasmic reticulum (ER) proteostasis pathways. This remodeling attenuates secretion of misfolded, aggregation-prone proteins during ER stress. Through these activities, the UPR has a critical role in preventing the extracellular protein aggregation associated with numerous human diseases. Here, we demonstrate that UPR activation also directly influences extracellular proteostasis through the upregulation and secretion of the ER HSP40 ERdj3/DNAJB11. Secreted ERdj3 binds misfolded proteins in the extracellular space, substoichiometrically inhibits protein aggregation, and attenuates proteotoxicity of disease-associated toxic prion protein. Moreover, ERdj3 can co-secrete with destabilized, aggregation-prone proteins in a stable complex under conditions where ER chaperoning capacity is overwhelmed, preemptively providing extracellular chaperoning of proteotoxic misfolded proteins that evade ER quality control. This regulated co-secretion of ERdj3 with misfolded clients directly links ER and extracellular proteostasis during conditions of ER stress. ERdj3 is, to our knowledge, the first metazoan chaperone whose secretion into the extracellular space is regulated by the UPR, revealing a new mechanism by which UPR activation regulates extracellular proteostasis. PMID:25361606

  8. Tula hantavirus triggers pro-apoptotic signals of ER stress in Vero E6 cells.

    PubMed

    Li, Xiao-Dong; Lankinen, Hilkka; Putkuri, Niina; Vapalahti, Olli; Vaheri, Antti

    2005-03-01

    Tula virus is a member of the Hantavirus genus of the family Bunyaviridae. Viruses of this family have an unusual pattern of intracellular maturation at the ER-Golgi compartment. We recently found that Tula virus, similar to several other hantaviruses, is able to induce apoptosis in cultured cells [Li, X.D., Kukkonen, S., Vapalahti, O., Plyusnin, A., Lankinen, H., Vaheri, A., 2004. Tula hantavirus infection of Vero E6 cells induces apoptosis involving caspase 8 activation. J. Gen. Virol. 85, 3261-3268.]. However, the cellular mechanisms remain to be clarified. In this study, we demonstrate that the progressive replication of Tula virus in Vero E6 cells initiates several death programs that are intimately associated with ER stress: (1) early activation of ER-resident caspase-12; (2) phosphorylation of Jun NH2-terminal kinase (JNK) and its downstream target transcriptional factor, c-jun; (3) induction of the pro-apoptotic transcriptional factor, growth arrest- and DNA damage-inducible gene 153, or C/EBP homologous protein (Gadd153/chop); and (4) changes in the ER-membrane protein BAP31 implying cross-talk with the mitochondrial apoptosis pathway. Furthermore, we confirmed that a sustained ER stress was induced marked by an increased expression of an ER chaperone Grp78/BiP. Taken together, we have identified involvement of ER stress-mediated death program in Tula virus-infected Vero E6 cells which provides a new approach to understand the mechanisms in hantavirus-induced apoptosis.

  9. Raloxifene upregulated mesangial cell MMP-2 activity via ER-β through transcriptional regulation.

    PubMed

    Fang, Ming; Wu, Xin-Chi; Huang, Wenlong

    2013-11-01

    Raloxifene, a second-generation selective estrogen receptor modulator, exerts estrogen-like effects in specific tissues. In this present study, we examined the effect of raloxifene on mesangial cell matrix metalloproteinase-2 (MMP-2) activity in streptozotocin-induced diabetic mice. Raloxifene increased the MMP-2 level in a dose-dependent and receptor-mediated manner. An antibody against estrogen receptor-β (ER-β) blocked the effect of raloxifene on MMP-2 expression, suggesting that the effect of raloxifene on MMP-2 activity was mediated by ER-β. In addition, the transcription factor AP-2, that plays an important role in MMP-2 gene transcription, was overexpressed under raloxifene simulation. The effect of MMP-2 was blocked by a selective inhibitor of the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) pathway, PD98059. Our results suggested that raloxifene-induced MMP-2 activity increases function through ERK/MAPK signaling via AP-2. In addition, we also found that the effect of raloxifene on MMP-2 expression was mediated via its binding to ER-β. However, at this stage of our investigation, (i) we could only show that both the binding to ER-β and the activation of the ERK/MAPK pathway impacted MMP-2 expression and (ii) we were unable to establish a relationship between ER-β binding and ERK/MAPK pathway activation.

  10. Endoplasmic reticulum: ER stress regulates mitochondrial bioenergetics

    PubMed Central

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

    2014-01-01

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

  11. Growth and characterization of ErAs:GaBix As1-x

    NASA Astrophysics Data System (ADS)

    Bomberger, Cory C.; Nieto-Pescador, Jesus; Lewis, Matthew R.; Tew, Bo E.; Wang, Yuejing; Chase, D. Bruce; Gundlach, Lars; Zide, Joshua M. O.

    2016-10-01

    We explore the growth and characterization of ErAs:GaBiAs as a candidate material for terahertz generation and detection via photoconductive switches. Spectrophotometry shows that the incorporation of small amounts of bismuth causes a reduction in the band gap, making these materials compatible with fiber-coupled lasers. ErAs pins the Fermi level within the band gap, causing high dark resistance while maintaining high mobility, shown by Hall effect measurements. Finally, transient absorption (optical pump, optical probe) measurements show that the ErAs provides a carrier recombination pathway, causing short carrier lifetimes. These material properties make ErAs:GaBiAs an interesting choice for fiber-coupled photoconductive switches.

  12. Rint1 inactivation triggers genomic instability, ER stress and autophagy inhibition in the brain

    PubMed Central

    Grigaravicius, P; Kaminska, E; Hübner, C A; McKinnon, P J; von Deimling, A; Frappart, P-O

    2016-01-01

    Endoplasmic reticulum (ER) stress, defective autophagy and genomic instability in the central nervous system are often associated with severe developmental defects and neurodegeneration. Here, we reveal the role played by Rint1 in these different biological pathways to ensure normal development of the central nervous system and to prevent neurodegeneration. We found that inactivation of Rint1 in neuroprogenitors led to death at birth. Depletion of Rint1 caused genomic instability due to chromosome fusion in dividing cells. Furthermore, Rint1 deletion in developing brain promotes the disruption of ER and Cis/Trans Golgi homeostasis in neurons, followed by ER-stress increase. Interestingly, Rint1 deficiency was also associated with the inhibition of the autophagosome clearance. Altogether, our findings highlight the crucial roles of Rint1 in vivo in genomic stability maintenance, as well as in prevention of ER stress and autophagy. PMID:26383973

  13. Adiponectin reduces ER stress-induced apoptosis through PPARα transcriptional regulation of ATF2 in mouse adipose

    PubMed Central

    Liu, Zhenjiang; Gan, Lu; Wu, Tianjiao; Feng, Fei; Luo, Dan; Gu, Huihui; Liu, Shimin; Sun, Chao

    2016-01-01

    Adiponectin is a cytokine produced predominantly by adipose tissue and correlates with glucose and lipid homeostasis. However, the effects of adiponectin on endoplasmic reticulum (ER) stress and apoptosis of adipose tissue remain elusive. In this study, we found that tunicamycin-induced ER stress increased serum free fatty acid (FFA) and impaired glucose tolerance, elevated the mRNA levels of GRP78, Chop, ATF2 and caspase 3, but reduced adiponectin mRNA level in white adipose tissue. Moreover, ER stress-triggered adipocyte apoptosis by increasing cellular FFA level and Ca2+ level. Further analysis revealed that adiponectin alleviated ER stress-induced adipocyte apoptosis by elevating peroxisome proliferator-activated receptor alpha (PPARα) mRNA level. Our data also confirmed that adiponectin reduced early apoptotic cells and blocked the mitochondrial apoptosis pathway by activating the AdipoR1/AMP-activated protein kinase (AMPK) signal pathway. In addition, PPARα bound to ATF2 promoter region and inhibited transcription of ATF2. The inhibition of adipocyte apoptosis by adiponectin was correlated with transcriptional suppression of ATF2. Furthermore, adiponectin inhibited ER stress-induced apoptosis by activating the AMPK/PKC pathway. In summary, our data demonstrate adiponectin inhibited ER stress and apoptosis of adipocyte in vivo and in vitro by activating the AMPK/PPARα/ATF2 pathway. Our study establishes that adiponectin is an important adipocytokine for preventing and treating obesity. PMID:27882945

  14. Inhibition of nonsense-mediated RNA decay by ER stress.

    PubMed

    Li, Zhelin; Vuong, John K; Zhang, Min; Stork, Cheryl; Zheng, Sika

    2017-03-01

    Nonsense-mediated RNA decay (NMD) selectively degrades mutated and aberrantly processed transcripts that contain premature termination codons (PTC). Cellular NMD activity is typically assessed using exogenous PTC-containing reporters. We overcame some inherently problematic aspects of assaying endogenous targets and developed a broadly applicable strategy to reliably and easily monitor changes in cellular NMD activity. Our new method was genetically validated for distinguishing NMD regulation from transcriptional control and alternative splicing regulation, and unexpectedly disclosed a different sensitivity of NMD targets to NMD inhibition. Applying this robust method for screening, we identified NMD-inhibiting stressors but also found that NMD inactivation was not universal to cellular stresses. The high sensitivity and broad dynamic range of our method revealed a strong correlation between NMD inhibition, endoplasmic reticulum (ER) stress, and polysome disassembly upon thapsigargin treatment in a temporal and dose-dependent manner. We found little evidence of calcium signaling mediating thapsigargin-induced NMD inhibition. Instead, we discovered that of the three unfolded protein response (UPR) pathways activated by thapsigargin, mainly protein kinase RNA-like endoplasmic reticulum kinase (PERK) was required for NMD inhibition. Finally, we showed that ER stress compounded TDP-43 depletion in the up-regulation of NMD isoforms that had been implicated in the pathogenic mechanisms of amyotrophic lateral sclerosis and frontotemporal dementia, and that the additive effect of ER stress was completely blocked by PERK deficiency.

  15. Completion report for Well Cluster ER-20-5

    SciTech Connect

    1997-03-01

    The Well Cluster ER-20-5 drilling and completion project was conducted for the US Department of Energy, Nevada Operations Office (DOE/NV), in support of the Nevada Environmental Restoration Project at the Nevada Test Site (NTS) in Nye County, Nevada. Its primary tasks include collecting geological, geophysical, hydrological, and water chemistry data from new and existing wells to define groundwater quality in addition to pathways and rates of groundwater migration. A program of drilling wells near the sites of selected underground nuclear tests (near-field drilling) was implemented to obtain site-specific data about the nature and extent of migration of radionuclides that might have been produced by an underground nuclear explosion. Well Cluster ER-20-5 is the first near-field drilling project initiated at the NTS. This document presents construction data and summarizes the scientific data gathered during the drilling and well-installation phases for all three holes drilled at Well Cluster ER-20-5. Some of this information is preliminary and unprocessed, but was released so that drilling, geotechnical, well design, and completion data could be rapidly disseminated. Additional information about water levels, aquifer testing, and groundwater sampling will be reported after any of this work is performed. Any additional geologic and/or geophysical investigations conducted for this project is described in one or more analysis and interpretation reports. The lithologic and stratigraphic logs, however, are provided in final form.

  16. Completion report for Well ER-19-1

    SciTech Connect

    1995-12-01

    Well ER-19-1 was drilled for the U.S. Department of Energy (DOE), Nevada Operations Office (DOE/NV), in support of the Nevada Environmental Restoration Project at the Nevada Test Site (NTS), Nye County, Nevada. IT Corporation (IT) was the principal environmental contractor for the project. The roles and responsibilities of IT and other contractors involved in the project are described in the Raytheon Services Nevada (RSN) Drilling and Completion Programs. The Well ER-19-1 investigation is part of the DOE`s Underground Test Area (UGTA) project at the NTS. The goals of the UGTA project include collecting geological, geophysical, hydrological, and water chemistry data from new and existing wells to define groundwater migration pathways, migration rates, and quality at the NTS. An additional major objective of drilling Well ER-19-1 was to develop dual-wall, reverse-circulation drilling technology for use on small-diameter wells at the NTS. The well will become part of the UGTA monitoring well network.

  17. Effective combination therapies in preclinical endocrine resistant breast cancer models harboring ER mutations

    PubMed Central

    Ladd, Brendon; Mazzola, Anne Marie; Bihani, Teeru; Lai, Zhongwu; Bradford, James; Collins, Michael; Barry, Evan; Goeppert, Anne U.; Weir, Hazel M.; Hearne, Kelly; Renshaw, Jonathan G.; Mohseni, Morvarid; Hurt, Elaine; Jalla, Sanjoo; Bao, Haifeng; Hollingsworth, Robert; Reimer, Corinne; Zinda, Michael; Fawell, Stephen; D'Cruz, Celina M.

    2016-01-01

    Although endocrine therapy is successfully used to treat patients with estrogen receptor (ER) positive breast cancer, a substantial proportion of this population will relapse. Several mechanisms of acquired resistance have been described including activation of the mTOR pathway, increased activity of CDK4 and activating mutations in ER. Using a patient derived xenograft model harboring a common activating ER ligand binding domain mutation (D538G), we evaluated several combinatorial strategies using the selective estrogen receptor degrader (SERD) fulvestrant in combination with chromatin modifying agents, and CDK4/6 and mTOR inhibitors. In this model, fulvestrant binds WT and MT ER, reduces ER protein levels, and downregulated ER target gene expression. Addition of JQ1 or vorinostat to fulvestrant resulted in tumor regression (41% and 22% regression, respectively) though no efficacy was seen when either agent was given alone. Interestingly, although the CDK4/6 inhibitor palbociclib and mTOR inhibitor everolimus were efficacious as monotherapies, long-term delayed tumor growth was only observed when co-administered with fulvestrant. This observation was consistent with a greater inhibition of compensatory signaling when palbociclib and everolimus were co-dosed with fulvestrant. The addition of fulvestrant to JQ1, vorinostat, everolimus and palbociclib also significantly reduced lung metastatic burden as compared to monotherapy. The combination potential of fulvestrant with palbociclib or everolimus were confirmed in an MCF7 CRISPR model harboring the Y537S ER activating mutation. Taken together, these data suggest that fulvestrant may have an important role in the treatment of ER positive breast cancer with acquired ER mutations. PMID:27472462

  18. BOREAS Level-0 ER-2 Aerial Photography

    NASA Technical Reports Server (NTRS)

    Newcomer, Jeffrey A.; Dominquez, Roseanne; Hall, Forrest G. (Editor)

    2000-01-01

    For BOReal Ecosystem-Atmosphere Study (BOREAS), the ER-2 and other aerial photography was collected to provide finely detailed and spatially extensive documentation of the condition of the primary study sites. The ER-2 aerial photography consists of color-IR transparencies collected during flights in 1994 and 1996 over the study areas.

  19. Ternary Dy-Er-Al magnetic refrigerants

    DOEpatents

    Gschneidner, Jr., Karl A.; Takeya, Hiroyuki

    1995-07-25

    A ternary magnetic refrigerant material comprising (Dy.sub.1-x Er.sub.x)Al.sub.2 for a magnetic refrigerator using the Joule-Brayton thermodynamic cycle spanning a temperature range from about 60K to about 10K, which can be adjusted by changing the Dy to Er ratio of the refrigerant.

  20. Ternary Dy-Er-Al magnetic refrigerants

    DOEpatents

    Gschneidner, K.A. Jr.; Takeya, Hiroyuki

    1995-07-25

    A ternary magnetic refrigerant material comprising (Dy{sub 1{minus}x}Er{sub x})Al{sub 2} for a magnetic refrigerator using the Joule-Brayton thermodynamic cycle spanning a temperature range from about 60K to about 10K, which can be adjusted by changing the Dy to Er ratio of the refrigerant. 29 figs.

  1. Estrogen receptors regulate innate immune cells and signaling pathways.

    PubMed

    Kovats, Susan

    2015-04-01

    Humans show strong sex differences in immunity to infection and autoimmunity, suggesting sex hormones modulate immune responses. Indeed, receptors for estrogens (ERs) regulate cells and pathways in the innate and adaptive immune system, as well as immune cell development. ERs are ligand-dependent transcription factors that mediate long-range chromatin interactions and form complexes at gene regulatory elements, thus promoting epigenetic changes and transcription. ERs also participate in membrane-initiated steroid signaling to generate rapid responses. Estradiol and ER activity show profound dose- and context-dependent effects on innate immune signaling pathways and myeloid cell development. While estradiol most often promotes the production of type I interferon, innate pathways leading to pro-inflammatory cytokine production may be enhanced or dampened by ER activity. Regulation of innate immune cells and signaling by ERs may contribute to the reported sex differences in innate immune pathways. Here we review the recent literature and highlight several molecular mechanisms by which ERs regulate the development or functional responses of innate immune cells.

  2. The TRC8 E3 ligase ubiquitinates MHC class I molecules before dislocation from the ER

    PubMed Central

    Stagg, Helen R.; Thomas, Mair; van den Boomen, Dick; Wiertz, Emmanuel J.H.J.; Drabkin, Harry A.; Gemmill, Robert M.

    2009-01-01

    The US2 and US11 gene products of human cytomegalovirus promote viral evasion by hijacking the endoplasmic reticulum (ER)–associated degradation (ERAD) pathway. US2 and US11 initiate dislocation of newly translocated major histocompatibility complex class I (MHC I) from the ER to the cytosol for proteasome-mediated degradation, thereby decreasing cell surface MHC I. Despite being instrumental in elucidating the mammalian ERAD pathway, the responsible E3 ligase or ligases remain unknown. Using a functional small interfering RNA library screen, we now identify TRC8 (translocation in renal carcinoma, chromosome 8 gene), an ER-resident E3 ligase previously implicated as a hereditary kidney cancer gene, as required for US2-mediated MHC I ubiquitination. Depletion of TRC8 prevents MHC I ubiquitination and dislocation by US2 and restores cell surface MHC I. TRC8 forms an integral part of a novel multiprotein ER complex that contains MHC I, US2, and signal peptide peptidase. Our data show that the TRC8 E3 ligase is required for MHC I dislocation from the ER and identify a new complex associated with mammalian ERAD. PMID:19720873

  3. Armet, a UPR-upregulated protein, inhibits cell proliferation and ER stress-induced cell death

    SciTech Connect

    Apostolou, Andria; Shen Yuxian; Liang Yan; Luo Jun; Fang Shengyun

    2008-08-01

    The accumulation of misfolded proteins in the endoplasmic reticulum (ER) causes ER stress that initiates the unfolded protein response (UPR). UPR activates both adaptive and apoptotic pathways, which contribute differently to disease pathogenesis. To further understand the functional mechanisms of UPR, we identified 12 commonly UPR-upregulated genes by expression microarray analysis. Here, we describe characterization of Armet/MANF, one of the 12 genes whose function was not clear. We demonstrated that the Armet/MANF protein was upregulated by various forms of ER stress in several cell lines as well as by cerebral ischemia of rat. Armet/MANF was localized in the ER and Golgi and was also a secreted protein. Silencing Armet/MANF by siRNA oligos in HeLa cells rendered cells more susceptible to ER stress-induced death, but surprisingly increased cell proliferation and reduced cell size. Overexpression of Armet/MANF inhibited cell proliferation and improved cell viability under glucose-free conditions and tunicamycin treatment. Based on its inhibitory properties for both proliferation and cell death we have demonstrated, Armet is, thus, a novel secreted mediator of the adaptive pathway of UPR.

  4. Facilitative plasma membrane transporters function during ER transit

    PubMed Central

    Takanaga, Hitomi; Frommer, Wolf B.

    2010-01-01

    Although biochemical studies suggested a high permeability of the endoplasmic reticulum (ER) membrane for small molecules, proteomics identified few specialized ER transporters. To test functionality of transporters during ER passage, we tested whether glucose transporters (GLUTs, SGLTs) destined for the plasma membrane are active during ER transit. HepG2 cells were characterized by low-affinity ER transport activity, suggesting that ER uptake is protein mediated. The much-reduced capacity of HEK293T cells to take up glucose across the plasma membrane correlated with low ER transport. Ectopic expression of GLUT1, -2, -4, or -9 induced GLUT isoform-specific ER transport activity in HEK293T cells. In contrast, the Na+-glucose cotransporter SGLT1 mediated efficient plasma membrane glucose transport but no detectable ER uptake, probably because of lack of a sufficient sodium gradient across the ER membrane. In conclusion, we demonstrate that GLUTs are sufficient for mediating ER glucose transport en route to the plasma membrane. Because of the low volume of the ER, trace amounts of these uniporters contribute to ER solute import during ER transit, while uniporters and cation-coupled transporters carry out export from the ER, together potentially explaining the low selectivity of ER transport. Expression levels and residence time of transporters in the ER, as well as their coupling mechanisms, could be key determinants of ER permeability.—Takanaga, H., Frommer, W. B. Facilitative plasma membrane transporters function during ER transit. PMID:20354141

  5. Peroxin-Dependent Targeting of a Lipid Droplet-Destined Membrane Protein to ER-subdomains

    PubMed Central

    Schrul, Bianca; Kopito, Ron R.

    2016-01-01

    SUMMARY Lipid droplets (LDs) are endoplasmic reticulum (ER)-derived lipid storage organelles uniquely encapsulated by phospholipid monolayers. LD membrane proteins are embedded into the monolayer in a monotopic hairpin-topology and therefore likely have requirements for their biogenesis distinct from those inserting as bitopic and polytopic proteins into phospholipid bilayers. UBXD8 belongs to a subfamily of hairpin-proteins that localize to both the ER and LDs, and are initially inserted into the cytoplasmic leaflet of the ER bilayer before partitioning to the LD monolayer. The molecular machinery responsible for inserting hairpin-proteins into membranes, however, is unknown. Here, we report that newly synthesized UBXD8 is posttranslationally inserted into discrete ER-subdomains by a mechanism requiring cytosolic PEX19 and membrane-integrated PEX3, proteins hitherto exclusively implicated in peroxisome biogenesis. Farnesylation of PEX19 uncouples ER/LD- and peroxisome targeting, expanding the function of this peroxin to an ER targeting pathway and suggesting a coordinated biogenesis of LDs and peroxisomes. PMID:27295553

  6. Optical excitation of Er centers in GaN epilayers grown by MOCVD

    NASA Astrophysics Data System (ADS)

    George, D. K.; Hawkins, M. D.; Jiang, H. X.; Lin, J. Y.; Zavada, J. M.; Vinh, N. Q.

    2016-02-01

    In this paper we present results of photoluminescence (PL), photoluminescence excitation (PLE), and time resolved PL spectroscopy of the 4I13/2 → 4I15/2 transition in Er optical centers in GaN epilayers grown by metal-organic chemical vapor deposition. Under resonance excitation via the higher-lying inner 4f shell transitions and band-to-band excitation of the semiconductor host, the PL and PLE spectra reveal an existence of two types of Er optical centers from isolated and the defect-related Er centers in GaN epilayers. These centers have different PL spectra, local defect environments, decay dynamics, and excitation cross-sections. The isolated Er optical center, which can be excited by either excitation mechanism, has the same decay dynamics, but possesses a much higher cross-section under band-to-band excitation. In contrast, the defect-related Er center can only be observed through band-to-band excitation but has the largest crosssection. Our results indicate pathways for efficient optical excitation of Er-doped GaN semiconductors.

  7. Modulation of endothelial cell migration by ER stress and insulin resistance: a role during maternal obesity?

    PubMed

    Sáez, Pablo J; Villalobos-Labra, Roberto; Westermeier, Francisco; Sobrevia, Luis; Farías-Jofré, Marcelo

    2014-01-01

    Adverse microenvironmental stimuli can trigger the endoplasmic reticulum (ER) stress pathway, which initiates the unfolded protein response (UPR), to restore protein-folding homeostasis. Several studies show induction of ER stress during obesity. Chronic UPR has been linked to different mechanisms of disease in obese and diabetic individuals, including insulin resistance (IR) and impaired angiogenesis. Endothelial cell (EC) migration is an initial step for angiogenesis, which is associated with remodeling of existing blood vessels. EC migration occurs according to the leader-follower model, involving coordinated processes of chemotaxis, haptotaxis, and mechanotaxis. Thus, a fine-tuning of EC migration is necessary to provide the right timing to form the required vessels during angiogenesis. ER stress modulates EC migration at different levels, usually impairing migration and angiogenesis, although different effects may be observed depending on the tissue and/or microenvironment. In the context of pregnancy, maternal obesity (MO) induces IR in the offspring. Interestingly, several proteins associated with obesity-induced IR are also involved in EC migration, providing a potential link with the ER stress-dependent alterations observed in obese individuals. Different signaling cascades that converge on cytoskeleton regulation directly impact EC migration, including the Akt and/or RhoA pathways. In addition, ER is the main intracellular reservoir for Ca(2+), which plays a pivotal role during EC migration. Therefore, ER stress-related alterations in Ca(2+) signaling or Ca(2+) levels might also produce distorted EC migration. However, the above findings have been studied in the context of adult obesity, and no information has been reported regarding the effect of MO on fetal EC migration. Here we summarize the state of knowledge about the possible mechanisms by which ER stress and IR might impact EC migration and angiogenesis in fetal endothelium exposed to MO during

  8. Electroreduction of Er 3+ in nonaqueous solvents

    DOE PAGES

    Small, Leo J.; Sears, Jeremiah M.; Lambert, Timothy N.; ...

    2016-09-15

    Here, the electroreduction of Er3+ in propylene carbonate, N,N-dimethylformamide, or a variety of quaternary ammonium ionic liquids (ILs) was investigated using [Er(OTf)3] and [Er(NTf2)3]. Systematic variation of the ILs' cation and anion, Er3+ salt, and electrode material revealed a disparity in electrochemical interactions not previously seen. For most ILs at a platinum electrode, cyclic voltammetry exhibits irreversible interactions between Er3+ salts and the electrode at potentials significantly less than the theoretical reduction potential for Er3+. Throughout all solvent–salt systems tested, a deposit could be formed on the electrode, though obtaining a high purity, crystalline Er0 deposit is challenging due tomore » the extreme reactivity of the deposit and resulting chemical interactions, often resulting in the formation of a complex, amorphous solid–electrolyte interface that slowed deposition rates. Comparison of platinum, gold, nickel, and glassy carbon (GC) working electrodes revealed oxidation processes unique to the platinum surface. While no appreciable reduction current was observed on GC at the potentials investigated, deposits were seen on platinum, gold, and nickel electrodes.« less

  9. Activation of transcription factor NF-kappaB by the adenovirus E3/19K protein requires its ER retention

    PubMed Central

    1996-01-01

    We have recently shown that the accumulation of diverse viral and cellular membrane proteins in the ER activates the higher eukaryotic transcription factor NF-kappaB. This defined a novel ER-nuclear signal transduction pathway, which is distinct from the previously described unfolded protein response (UPR). The well characterized UPR pathway is activated by the presence of un- or malfolded proteins in the ER. In contrast, the ER stress signal which activates the NF-kappaB pathway is not known. Here we used the adenovirus early region protein E3/19K as a model to investigate the nature of the NF-kappaB-activating signal emitted by the ER. E3/19K resides in the endoplasmic reticulum where it binds to MHC class I molecules, thereby preventing their transport to the cell surface. It is maintained in the ER by a retention signal sequence in its carboxy terminus, which causes the protein to be continuously retrieved to the ER from post-ER compartments. Mutation of this sequence allows E3/19K to reach the cell surface. We show here that expression of E3/19K potently activates a functional NF-kappaB transcription factor. The activated NF-kappaB complexes contained p50/p65 and p50/c-rel heterodimers. E3/19K interaction with MHC class I was not important for NF-kappaB activation since mutant proteins which no longer bind MHC molecules remained fully capable of inducing NF- kappaB. However, activation of both NF-kappaB DNA binding and kappaB- dependent transactivation relied on E3/19K ER retention: mutants, which were expressed on the cell surface, could no longer activate the transcription factor. This identifies the NF-kappaB-activating signal as the accumulation of proteins in the ER membrane, a condition we have termed "ER overload." We show that ER overload-mediated NF-kappaB activation but not TNF-stimulated NF-kappaB induction can be inhibited by the intracellular Ca2+ chelator TMB-8. Moreover, treatment of cells with two inhibitors of the ER-resident Ca(2+) -dependent

  10. Protein kinase R-like ER kinase and its role in endoplasmic reticulum stress-decided cell fate.

    PubMed

    Liu, Z; Lv, Y; Zhao, N; Guan, G; Wang, J

    2015-07-30

    Over the past few decades, understandings and evidences concerning the role of endoplasmic reticulum (ER) stress in deciding the cell fate have been constantly growing. Generally, during ER stress, the signal transductions are mainly conducted by three ER stress transducers: protein kinase R-like endoplasmic reticulum kinase (PERK), inositol-requiring kinase 1 (IRE1) and activating transcription factor 6 (ATF6). Consequently, the harmful stimuli from the ER stress transducers induce apoptosis and autophagy, which share several crosstalks and eventually decide the cell fate. The dominance of apoptosis or autophagy induced by ER stress depends on the type and degree of the stimuli. When ER stress is too severe and prolonged, apoptosis is induced to eliminate the damaged cells; however, when stimuli are mild, cell survival is promoted to maintain normal physiological functions by inducing autophagy. Although all the three pathways participate in ER stress-induced apoptosis and autophagy, PERK shows several unique characteristics by interacting with some specific downstream effectors. Notably, there are some preliminary findings on PERK-dependent mechanisms switching autophagy and apoptosis. In this review, we particularly focused on the novel, intriguing and complicated role of PERK in ER stress-decided cell fate, and also discussed more roles of PERK in restoring cellular homeostasis. However, more in-depth knowledge of PERK in the future would facilitate our understanding about many human diseases and benefit in searching for new molecular therapeutic targets.

  11. High Performance Calcium Titanate Nanoparticle ER Fluids

    NASA Astrophysics Data System (ADS)

    Wang, Xuezhao; Shen, Rong; Wen, Weijia; Lu, Kunquan

    A type of calcium titanate (CTO) nanoparticles was synthesized by means of wet chemical method [1] without coating on the particles. The CTO/silicone oil ER fluid exhibits excellent electrorheological properties: high shear stress (~50-100 kPa) under dc electric field, a low current density (less than 2μA/cm2 at 5kV/mm), and long term stability against sedimentation. Although there are not special additives in the ER fluids, it is found from the chemical analysis that a trace of alkyl group, hydroxyl group, carbonyl group and some ions is remained in the particles which may dominate the ER response.

  12. Targeting the ER-Autophagy System in the Trabecular Meshwork to Treat Glaucoma

    PubMed Central

    Stothert, Andrew R.; Fontaine, Sarah N.; Sabbagh, Jonathan J.; Dickey, Chad A.

    2015-01-01

    A major drainage network involved in aqueous humor dynamics is the conventional outflow pathway, which is gated by the trabecular meshwork (TM). The TM acts as a molecular sieve, providing resistance to aqueous outflow, which is responsible for regulating intraocular pressure (IOP). If the TM is damaged, aqueous outflow is impaired, IOP increases and glaucoma can manifest. Mutations in the MYOC gene cause hereditary primary open-angle glaucoma (POAG) by promoting the abnormal amyloidosis of the myocilin protein in the endoplasmic reticulum (ER), leading to ER stress-induced TM cell death. Myocilin accumulation is observed in approximately 70–80% of all glaucoma cases suggesting that environmental or other genetic factors may also promote myocilin toxicity. For example, simply preventing myocilin glycosylation is sufficient to promote its abnormal accretion. These myocilin amyloids are unique as there are no other known pathogenic proteins that accumulate within the ER of TM cells and cause toxicity. Moreover, this pathogenic accumulation only kills TM cells, despite expression of this protein in other cell types, suggesting that another modifier exclusive to the TM participates in the proteotoxicity of myocilin. ER autophagy (reticulophagy) is one of the pathways essential for myocilin clearance that can be impacted dramatically by aging and other environmental factors such as nutrition. This review will discuss the link between myocilin and autophagy, evaluating the role of this degradation pathway in glaucoma as well as its potential as a therapeutic target. PMID:26302411

  13. Bridges between mitochondrial oxidative stress, ER stress and mTOR signaling in pancreatic β cells.

    PubMed

    Wang, Jing; Yang, Xin; Zhang, Jingjing

    2016-08-01

    Pancreatic β cell dysfunction, i.e., failure to provide insulin in concentrations sufficient to control blood sugar, is central to the etiology of all types of diabetes. Current evidence implicates mitochondrial oxidative stress and endoplasmic reticulum (ER) stress in pancreatic β cell loss and impaired insulin secretion. Oxidative and ER stress are interconnected so that misfolded proteins induce reactive oxygen species (ROS) production; likewise, oxidative stress disturbs the ER redox state thereby disrupting correct disulfide bond formation and proper protein folding. mTOR signaling regulates many metabolic processes including protein synthesis, cell growth, survival and proliferation. Oxidative stress inhibits mTORC1, which is considered an important suppressor of mitochondrial oxidative stress in β cells, and ultimately, controls cell survival. The interplay between ER stress and mTORC1 is complicated, since the unfolded protein response (UPR) activation can occur upstream or downstream of mTORC1. Persistent activation of mTORC1 initiates protein synthesis and UPR activation, while in the later phase induces ER stress. Chronic activation of ER stress inhibits Akt/mTORC1 pathway, while under particular settings, acute activation of UPR activates Akt-mTOR signaling. Thus, modulating mitochondrial oxidative stress and ER stress via mTOR signaling may be an approach that will effectively suppress obesity- or glucolipotoxicity-induced metabolic disorders such as insulin resistance and type 2 diabetes mellitus (T2DM). In this review, we focus on the regulations between mTOR signaling and mitochondrial oxidative or ER stress in pancreatic β cells.

  14. [From endoplasmic reticulum to Golgi apparatus: a secretory pathway controlled by signal molecules].

    PubMed

    Wang, Jiasheng; Luo, Jianhong; Zhang, Xiaomin

    2013-07-01

    Protein transport from endoplasmic reticulum (ER) to Golgi apparatus has long been known to be a central process for protein quality control and sorting. Recent studies have revealed that a large number of signal molecules are involved in regulation of membrane trafficking through ER, ER-Golgi intermediate compartment and Golgi apparatus. These molecules can significantly change the transport rate of proteins by regulating vesicle budding and fusion. Protein transport from ER to Golgi apparatus is not only controlled by signal pathways triggered from outside the cell, it is also regulated by feedback signals from the transport pathway.

  15. Environmental release summary (ERS) database CY 1997

    SciTech Connect

    Gleckler, B.P.

    1998-07-01

    This report discusses the Environmental Release Summary (ERS) database. The current needs of the Effluent and Environmental database is continually modified to fulfill monitoring (EEM) program (managed by Waste Management Federal Services of Hanford, Incorporated, Air and Water Services Organization). Changes are made to accurately calculate current releases, to affect how past releases are calculated. This document serves as a snap-shot of the database and software for the CY-1997 data and releases. This document contains all of the relevant data for calculating radioactive-airborne and liquid effluent. The ERS database is the official repository for the CY-1997 ERS release reports and the settings used to generate those reports. As part of the Tri-Party Agreement, FDH is committed to provide a hard copy of the ERS database for Washington State Department of Ecology, upon request. This document also serves as that hard copy for the last complete calendar year.

  16. ER Consolidated Quarterly Report October 2014

    SciTech Connect

    Cochran, John R.

    2014-10-01

    This Environmental Restoration Operations (ER) Consolidated Quarterly Report (ER Quarterly Report) provides the status of ongoing corrective actions and related Long- Term Stewardship (LTS) activities being implemented by Sandia National Laboratories, New Mexico (SNL/NM) ER for the April, May, and June 2014 quarterly reporting period. Section 2.0 provides the status of ER Operations activities including closure activities for the Mixed Waste Landfill (MWL), project management and site closure, and hydrogeologic characterizations. Section 3.0 provides the status of LTS activities that relate to the Chemical Waste Landfill (CWL) and the associated Corrective Action Management Unit (CAMU). Section 4.0 provides the references noted in Section I of this report.

  17. FIRE_ACE_ER2_MAS

    Atmospheric Science Data Center

    2015-10-28

    ... First ISCCP Regional Experiment (FIRE) Arctic Cloud Experiment (ACE) NASA ER-2 Moderate Resolution Imaging ... SSFR Location:  Northern Alaska Arctic Ocean Spatial Coverage:  Fairbanks, Alaska and the surrounding ...

  18. Topography over South America from ERS altimetry

    NASA Technical Reports Server (NTRS)

    Brenner, Anita; Frey, Herb; DiMarzio, John; Tsaoussi, Lucia

    1997-01-01

    The results of the surface topography mapping of South America during the ERS-1 geodetic mission are presented. The altimeter waveforms, the range measurement, and the internal and Doppler range corrections were obtained. The atmospheric corrections and solid tides were calculated. Comparisons between Shuttle laser altimetry and ERS-1 altimetry grid showed good agreement. Satellite radar altimetry data can be used to improve the topographic knowledge of regions for which only poor elevation data currently exist.

  19. Apolipoprotein E receptor-2 (ApoER2) mediates selenium uptake from selenoprotein P by the mouse testis.

    PubMed

    Olson, Gary E; Winfrey, Virginia P; Nagdas, Subir K; Hill, Kristina E; Burk, Raymond F

    2007-04-20

    Selenium is a micronutrient that is essential for the production of normal spermatozoa. The selenium-rich plasma protein selenoprotein P (Sepp1) is required for maintenance of testis selenium and for fertility of the male mouse. Sepp1 trafficking in the seminiferous epithelium was studied using conventional methods and mice with gene deletions. Immunocytochemistry demonstrated that Sepp1 is present in vesicle-like structures in the basal region of Sertoli cells, suggesting that the protein is taken up intact. Sepp1 affinity chromatography of a testicular extract followed by mass spectrometry-based identification of bound proteins identified apolipoprotein E receptor 2 (ApoER2) as a candidate testis Sepp1 receptor. In situ hybridization analysis identified Sertoli cells as the only cell type in the seminiferous epithelium with detectable ApoER2 expression. Testis selenium levels in apoER2(-/-) males were sharply reduced from those in apoER2(+/+) males and were comparable with the depressed levels found in Sepp1(-/-) males. However, liver selenium levels were unchanged by deletion of apoER2. Immunocytochemistry did not detect Sepp1 in the Sertoli cells of apoER2(-/-) males, consistent with a defect in the receptor-mediated Sepp1 uptake pathway. Phase contrast microscopy revealed identical sperm defects in apoER2(-/-) and Sepp1(-/-) mice. Co-immunoprecipitation analysis demonstrated an interaction of testis ApoER2 with Sepp1. These data demonstrate that Sertoli cell ApoER2 is a Sepp1 receptor and a component of the selenium delivery pathway to spermatogenic cells.

  20. Amyotrophic lateral sclerosis (ALS)-associated VAPB-P56S inclusions represent an ER quality control compartment

    PubMed Central

    2013-01-01

    Background Protein aggregation and the formation of intracellular inclusions are a central feature of many neurodegenerative disorders, but precise knowledge about their pathogenic role is lacking in most instances. Here we have characterized inclusions formed in transgenic mice carrying the P56S mutant form of VAPB that causes various motor neuron syndromes including ALS8. Results Inclusions in motor neurons of VAPB-P56S transgenic mice are characterized by the presence of smooth ER-like tubular profiles, and are immunoreactive for factors that operate in the ER associated degradation (ERAD) pathway, including p97/VCP, Derlin-1, and the ER membrane chaperone BAP31. The presence of these inclusions does not correlate with signs of axonal and neuronal degeneration, and axotomy leads to their gradual disappearance, indicating that they represent reversible structures. Inhibition of the proteasome and knockdown of the ER membrane chaperone BAP31 increased the size of mutant VAPB inclusions in primary neuron cultures, while knockdown of TEB4, an ERAD ubiquitin-protein ligase, reduced their size. Mutant VAPB did not codistribute with mutant forms of seipin that are associated with an autosomal dominant motor neuron disease, and accumulate in a protective ER derived compartment termed ERPO (ER protective organelle) in neurons. Conclusions The data indicate that the VAPB-P56S inclusions represent a novel reversible ER quality control compartment that is formed when the amount of mutant VAPB exceeds the capacity of the ERAD pathway and that isolates misfolded and aggregated VAPB from the rest of the ER. The presence of this quality control compartment reveals an additional level of flexibility of neurons to cope with misfolded protein stress in the ER. PMID:24252306

  1. Characterization of the ER-Targeted Low Affinity Ca2+ Probe D4ER

    PubMed Central

    Greotti, Elisa; Wong, Andrea; Pozzan, Tullio; Pendin, Diana; Pizzo, Paola

    2016-01-01

    Calcium ion (Ca2+) is a ubiquitous intracellular messenger and changes in its concentration impact on nearly every aspect of cell life. Endoplasmic reticulum (ER) represents the major intracellular Ca2+ store and the free Ca2+ concentration ([Ca2+]) within its lumen ([Ca2+]ER) can reach levels higher than 1 mM. Several genetically-encoded ER-targeted Ca2+ sensors have been developed over the last years. However, most of them are non-ratiometric and, thus, their signal is difficult to calibrate in live cells and is affected by shifts in the focal plane and artifactual movements of the sample. On the other hand, existing ratiometric Ca2+ probes are plagued by different drawbacks, such as a double dissociation constant (Kd) for Ca2+, low dynamic range, and an affinity for the cation that is too high for the levels of [Ca2+] in the ER lumen. Here, we report the characterization of a recently generated ER-targeted, Förster resonance energy transfer (FRET)-based, Cameleon probe, named D4ER, characterized by suitable Ca2+ affinity and dynamic range for monitoring [Ca2+] variations within the ER. As an example, resting [Ca2+]ER have been evaluated in a known paradigm of altered ER Ca2+ homeostasis, i.e., in cells expressing a mutated form of the familial Alzheimer’s Disease-linked protein Presenilin 2 (PS2). The lower Ca2+ affinity of the D4ER probe, compared to that of the previously generated D1ER, allowed the detection of a conspicuous, more clear-cut, reduction in ER Ca2+ content in cells expressing mutated PS2, compared to controls. PMID:27598166

  2. Enhanced recovery pathway for thoracic surgery in the UK

    PubMed Central

    Solli, Piergiorgio

    2016-01-01

    Background Enhanced recovery (ER) refers to a combination of perioperative interventions designed to minimise the impact of surgery on patients’ recovery in order to reduce postoperative complications and to allow an early discharge reducing hospital costs. Methods An ER protocol was established at our institution following a review of the best evidence available. We introduced a multi-disciplinary integrated perioperative pathway by engaging with every person involved, including the patients themselves. The programme was monitored using specifically-designed patients related outcome measures (PROMs). Results One-hundred and fifty-four ER patients were compared with 171 controls from the year before ER was introduced. There was an 80% increase in same-day admissions, with a net gain of more than 300 patient bed-days. The ER group had a significantly higher number of procedures performed by video assisted thoracoscopic surgery (VATS) (ER, 32.9% vs. 9.4%, P=0.0001) and a lower rate of admission to the intensive care unit (ER, 5.8% versus 12.9%, P=0.04). Patients on the ER programme had a significantly reduced postoperative length of stay (mean ER, 5.2 vs. 11.7 days, P<0.0001). Patient satisfaction was higher in the ER group after a patient survey. The project resulted in a net saving of £214,000 for the Trust for the 2013/2014 financial year. We were also able to increase the number of patients who underwent thoracic surgery in 2013/2014 by 30% (159 patients) compared with 2012/2013. Conclusions The ER pathway has proven to be a safe perioperative management strategy to improve patient satisfaction and to reduce the length of hospital stay and cost after major thoracic surgery, without increasing morbidity or mortality. PMID:26941974

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

    PubMed

    Häcker, Georg

    2014-10-01

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

  4. There's Something Wrong with my MAM; the ER-Mitochondria Axis and Neurodegenerative Diseases.

    PubMed

    Paillusson, Sebastien; Stoica, Radu; Gomez-Suaga, Patricia; Lau, Dawn H W; Mueller, Sarah; Miller, Tanya; Miller, Christopher C J

    2016-03-01

    Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis with associated frontotemporal dementia (ALS/FTD) are major neurodegenerative diseases for which there are no cures. All are characterised by damage to several seemingly disparate cellular processes. The broad nature of this damage makes understanding pathogenic mechanisms and devising new treatments difficult. Can the different damaged functions be linked together in a common disease pathway and which damaged function should be targeted for therapy? Many functions damaged in neurodegenerative diseases are regulated by communications that mitochondria make with a specialised region of the endoplasmic reticulum (ER; mitochondria-associated ER membranes or 'MAM'). Moreover, several recent studies have shown that disturbances to ER-mitochondria contacts occur in neurodegenerative diseases. Here, we review these findings.

  5. Drug Synergism of Proteasome Inhibitors and Mitotane by Complementary Activation of ER Stress in Adrenocortical Carcinoma Cells.

    PubMed

    Kroiss, Matthias; Sbiera, Silviu; Kendl, Sabine; Kurlbaum, Max; Fassnacht, Martin

    2016-12-01

    Mitotane is the only drug approved for treatment of the orphan disease adrenocortical carcinoma (ACC) and was recently shown to be the first clinically used drug acting through endoplasmic reticulum (ER)-stress induced by toxic lipids. Since mitotane has limited clinical activity as monotherapy, we here study the potential of activating ER-stress through alternative pathways. The single reliable NCI-H295 cell culture model for ACC was used to study the impact MG132, bortezomib (BTZ) and carfilzomib (CFZ) on mRNA and protein expression of ER-stress markers, cell viability and steroid hormone secretion. We found all proteasome inhibitors alone to trigger expression of mRNA (spliced X-box protein 1, XBP1) and protein markers indicative of the inositol-requiring enzyme 1 (IRE1) dependent pathway of ER-stress but not phosphorylation of eukaryotic initiation factor 2α (eIF2α), a marker of the PRKR-like endoplasmic reticulum kinase (PERK)-dependent pathway. Whereas mitotane alone activated both pathways, combination of BTZ and CFZ with low-dose mitotane blocked mitotane-induced eIF2α phosphorylation but increased XBP1-mRNA splicing indicating that proteasome inhibitors can commit signalling towards a single ER-stress pathway in ACC cells. By applying the median effect model of drug combinations using cell viability as a read out, we determined significant drug synergism between mitotane and both BTZ and CFZ. In conclusion, combination of mitotane with activators of ER-stress through the unfolded protein response is synergistic in an ACC cell culture model. Since proteasome inhibitors are readily available clinically, they are attractive candidates to study for ACC treatment in clinical trials in combination with mitotane.

  6. Coordination of stress, Ca2+, and immunogenic signaling pathways by PERK at the endoplasmic reticulum.

    PubMed

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

    2016-07-01

    The endoplasmic reticulum (ER) is the main coordinator of intracellular Ca2+ signaling, protein synthesis, and folding. The ER is also implicated in the formation of contact sites with other organelles and structures, including mitochondria, plasma membrane (PM), and endosomes, thereby orchestrating through interorganelle signaling pathways, a variety of cellular responses including Ca2+ homeostasis, metabolism, and cell death signaling. Upon loss of its folding capacity, incited by a number of stress signals including those elicited by various anticancer therapies, the unfolded protein response (UPR) is launched to restore ER homeostasis. The ER stress sensor protein kinase RNA-like ER kinase (PERK) is a key mediator of the UPR and its role during ER stress has been largely recognized. However, growing evidence suggests that PERK may govern signaling pathways through UPR-independent functions. Here, we discuss emerging noncanonical roles of PERK with particular relevance for the induction of danger or immunogenic signaling and interorganelle communication.

  7. The ER stress regulator Bip mediates cadmium-induced autophagy and neuronal senescence

    PubMed Central

    Wang, Tao; Yuan, Yan; Zou, Hui; Yang, Jinlong; Zhao, Shiwen; Ma, Yonggang; Wang, Yi; Bian, Jianchun; Liu, Xuezhong; Gu, Jianhong; Liu, Zongping; Zhu, Jiaqiao

    2016-01-01

    Autophagy is protective in cadmium (Cd)-induced oxidative damage. Endoplasmic reticulum (ER) stress has been shown to induce autophagy in a process requiring the unfolded protein response signalling pathways. Cd treatment significantly increased senescence in neuronal cells, which was aggravated by 3-MA or silencing of Atg5 and abolished by rapamycin. Cd increased expression of ER stress regulators Bip, chop, eIf2α, and ATF4, and activated autophagy as evidenced by upregulated LC3. Moreover, the ER stress inhibitor mithramycin inhibited the expression of ER stress protein chaperone Bip and blocked autophagic flux. Downregulating Bip significantly blocked the conversion of LC3-I to LC3-II, decreased LC3 puncta formation, and prevented the increase of senescence in PC12 cells. Interestingly, knocking down Bip regulated the expression of p-AMPK, p-AKT and p-s6k induced by Cd. BAPTA, a Bip inhibitor, decreased the expression of p-AMPK and LC3-II, but enhanced neuronal senescence. In addition, we found that siRNA for Bip enhanced GATA4 expression after 6 h Cd exposure in PC12 cells, while rapamycin treatment decreased GATA4 levels induced by 24 h Cd exposure. These results indicate that autophagy degraded GATA4 in a Bip-dependent way. Our findings suggest that autophagy regulated by Bip expression after ER stress suppressed Cd-induced neuronal senescence. PMID:27905509

  8. Transcription regulator TRIP-Br2 mediates ER stress-induced brown adipocytes dysfunction

    PubMed Central

    Qiang, Guifen; Whang Kong, Hyerim; Gil, Victoria; Liew, Chong Wee

    2017-01-01

    In contrast to white adipose tissue, brown adipose tissue (BAT) is known to play critical roles for both basal and inducible energy expenditure. Obesity is associated with reduction of BAT function; however, it is not well understood how obesity promotes BAT dysfunction, especially at the molecular level. Here we show that the transcription regulator TRIP-Br2 mediates ER stress-induced inhibition of lipolysis and thermogenesis in BAT. Using in vitro, ex vivo, and in vivo approaches, we demonstrate that obesity-induced inflammation upregulates brown adipocytes TRIP-Br2 expression via the ER stress pathway and amelioration of ER stress in mice completely abolishes high fat diet-induced upregulation of TRIP-Br2 in BAT. We find that increased TRIP-Br2 significantly inhibits brown adipocytes thermogenesis. Finally, we show that ablation of TRIP-Br2 ameliorates ER stress-induced inhibition on lipolysis, fatty acid oxidation, oxidative metabolism, and thermogenesis in brown adipocytes. Taken together, our current study demonstrates a role for TRIP-Br2 in ER stress-induced BAT dysfunction, and inhibiting TRIP-Br2 could be a potential approach for counteracting obesity-induced BAT dysfunction. PMID:28067333

  9. JNK interaction with Sab mediates ER stress induced inhibition of mitochondrial respiration and cell death

    PubMed Central

    Win, S; Than, T A; Fernandez-Checa, J C; Kaplowitz, N

    2014-01-01

    Our aim was to better understand the mechanism and importance of sustained c-Jun N-terminal kinase (JNK) activation in endoplasmic reticulum (ER) stress and effects of ER stress on mitochondria by determining the role of mitochondrial JNK binding protein, Sab. Tunicamycin or brefeldin A induced a rapid and marked decline in basal mitochondrial respiration and reserve-capacity followed by delayed mitochondrial-mediated apoptosis. Knockdown of mitochondrial Sab prevented ER stress-induced sustained JNK activation, impaired respiration, and apoptosis, but did not alter the magnitude or time course of activation of ER stress pathways. P-JNK plus adenosine 5′-triphosphate (ATP) added to isolated liver mitochondria promoted superoxide production, which was amplified by addition of calcium and inhibited by a blocking peptide corresponding to the JNK binding site on Sab (KIM1). This peptide also blocked tunicamycin-induced inhibition of cellular respiration. In conclusion, ER stress triggers an interaction of JNK with mitochondrial Sab, which leads to impaired respiration and increased mitochondrial reactive oxygen species, sustaining JNK activation culminating in apoptosis. PMID:24407242

  10. JNK interaction with Sab mediates ER stress induced inhibition of mitochondrial respiration and cell death.

    PubMed

    Win, S; Than, T A; Fernandez-Checa, J C; Kaplowitz, N

    2014-01-09

    Our aim was to better understand the mechanism and importance of sustained c-Jun N-terminal kinase (JNK) activation in endoplasmic reticulum (ER) stress and effects of ER stress on mitochondria by determining the role of mitochondrial JNK binding protein, Sab. Tunicamycin or brefeldin A induced a rapid and marked decline in basal mitochondrial respiration and reserve-capacity followed by delayed mitochondrial-mediated apoptosis. Knockdown of mitochondrial Sab prevented ER stress-induced sustained JNK activation, impaired respiration, and apoptosis, but did not alter the magnitude or time course of activation of ER stress pathways. P-JNK plus adenosine 5'-triphosphate (ATP) added to isolated liver mitochondria promoted superoxide production, which was amplified by addition of calcium and inhibited by a blocking peptide corresponding to the JNK binding site on Sab (KIM1). This peptide also blocked tunicamycin-induced inhibition of cellular respiration. In conclusion, ER stress triggers an interaction of JNK with mitochondrial Sab, which leads to impaired respiration and increased mitochondrial reactive oxygen species, sustaining JNK activation culminating in apoptosis.

  11. 20 CFR 216.68 - Disability period for widow(er), surviving divorced spouse, or remarried widow(er).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Disability period for widow(er), surviving divorced spouse, or remarried widow(er). 216.68 Section 216.68 Employees' Benefits RAILROAD RETIREMENT... Divorced Spouse, and Remarried Widow(er) Annuities § 216.68 Disability period for widow(er),...

  12. Mechanisms of oestrogen receptor (ER) gene regulation in breast cancer

    PubMed Central

    2016-01-01

    Most breast cancers are driven by a transcription factor called oestrogen receptor (ER). Understanding the mechanisms of ER activity in breast cancer has been a major research interest and recent genomic advances have revealed extraordinary insights into how ER mediates gene transcription and what occurs during endocrine resistance. This review discusses our current understanding on ER activity, with an emphasis on several evolving, but important areas of ER biology. PMID:26884552

  13. Involvement of TR3/Nur77 translocation to the endoplasmic reticulum in ER stress-induced apoptosis

    SciTech Connect

    Liang Bin; Song Xuhong; Liu Gefei; Li Rui; Xie Jianping; Xiao Lifeng; Du Mudan; Zhang Qiaoxia; Xu Xiaoyuan; Gan Xueqiong; Huang Dongyang . E-mail: huangdy@stu.edu.cn

    2007-08-01

    Nuclear orphan receptor TR3/Nur77/NGFI-B is a novel apoptotic effector protein that initiates apoptosis largely by translocating from the nucleus to the mitochondria, causing the release of cytochrome c. However, it is possible that TR3 translocates to other organelles. The present study was designed to determine the intracellular localization of TR3 following CD437-induced nucleocytoplasmic translocation and the mechanisms involved in TR3-induced apoptosis. In human neuroblastoma SK-N-SH cells and human esophageal squamous carcinoma EC109 and EC9706 cells, 5 {mu}M CD437 induced translocation of TR3 to the endoplasmic reticulum (ER). This distribution was confirmed by immunofluorescence analysis, subcellular fractionation analysis and coimmunoprecipitation analysis. The translocated TR3 interacted with ER-targeting Bcl-2; initiated an early release of Ca{sup 2+} from ER; resulted in ER stress and induced apoptosis through ER-specific caspase-4 activation, together with induction of mitochondrial stress and subsequent activation of caspase-9. Our results identified a novel distribution of TR3 in the ER and defined two parallel mitochondrial- and ER-based pathways that ultimately result in apoptotic cell death.

  14. Melatonin Mediates Protective Effects against Kainic Acid-Induced Neuronal Death through Safeguarding ER Stress and Mitochondrial Disturbance

    PubMed Central

    Xue, Feixiao; Shi, Cai; Chen, Qingjie; Hang, Weijian; Xia, Liangtao; Wu, Yue; Tao, Sophia Z.; Zhou, Jie; Shi, Anbing; Chen, Juan

    2017-01-01

    Kainic acid (KA)-induced neuronal death is linked to mitochondrial dysfunction and ER stress. Melatonin is known to protect hippocampal neurons from KA-induced apoptosis, but the exact mechanisms underlying melatonin protective effects against neuronal mitochondria disorder and ER stress remain uncertain. In this study, we investigated the sheltering roles of melatonin during KA-induced apoptosis by focusing on mitochondrial dysfunction and ER stress mediated signal pathways. KA causes mitochondrial dynamic disorder and dysfunction through calpain activation, leading to neuronal apoptosis. Ca2+ chelator BAPTA-AM and calpain inhibitor calpeptin can significantly restore mitochondrial morphology and function. ER stress can also be induced by KA treatment. ER stress inhibitor 4-phenylbutyric acid (PBA) attenuates ER stress-mediated apoptosis and mitochondrial disorder. It is worth noting that calpain activation was also inhibited under PBA administration. Thus, we concluded that melatonin effectively inhibits KA-induced calpain upregulation/activation and mitochondrial deterioration by alleviating Ca2+ overload and ER stress. PMID:28293167

  15. ER-associated SNAREs and Sey1p mediate nuclear fusion at two distinct steps during yeast mating.

    PubMed

    Rogers, Jason V; Arlow, Tim; Inkellis, Elizabeth R; Koo, Timothy S; Rose, Mark D

    2013-12-01

    During yeast mating, two haploid nuclei fuse membranes to form a single diploid nucleus. However, the known proteins required for nuclear fusion are unlikely to function as direct fusogens (i.e., they are unlikely to directly catalyze lipid bilayer fusion) based on their predicted structure and localization. Therefore we screened known fusogens from vesicle trafficking (soluble N-ethylmaleimide-sensitive factor attachment protein receptors [SNAREs]) and homotypic endoplasmic reticulum (ER) fusion (Sey1p) for additional roles in nuclear fusion. Here we demonstrate that the ER-localized SNAREs Sec20p, Ufe1p, Use1p, and Bos1p are required for efficient nuclear fusion. In contrast, Sey1p is required indirectly for nuclear fusion; sey1Δ zygotes accumulate ER at the zone of cell fusion, causing a block in nuclear congression. However, double mutants of Sey1p and Sec20p, Ufe1p, or Use1p, but not Bos1p, display extreme ER morphology defects, worse than either single mutant, suggesting that retrograde SNAREs fuse ER in the absence of Sey1p. Together these data demonstrate that SNAREs mediate nuclear fusion, ER fusion after cell fusion is necessary to complete nuclear congression, and there exists a SNARE-mediated, Sey1p-independent ER fusion pathway.

  16. Mobile ER-to-Golgi but not post-Golgi membrane transport carriers disappear during the terminal myogenic differentiation.

    PubMed

    Nevalainen, Mika; Kaisto, Tuula; Metsikkö, Kalervo

    2010-10-01

    The organelles of the exocytic pathway undergo a profound reorganization during the myogenic differentiation. Here, we have investigated the dynamics of the membrane trafficking at various stages of the differentiation process by using the green fluorescent protein-tagged, temperature-sensitive vesicular stomatitis virus G protein (tsG-GFP) as a marker. At the restrictive temperature of 39°C, the tsG-GFP located to the endoplasmic reticulum (ER) at each stage of differentiation. Mobile membrane containers moving from the ER to the Golgi elements were seen in myoblasts and myotubes upon shifting the temperature to 20°C. In adult myofibers, in contrast, such containers were not seen although the tsG-GFP rapidly shifted from the ER to the Golgi elements. The mobility of tsG-GFP in the myofiber ER was restricted, suggesting localization in an ER sub-compartment. Contrasting with the ER-to-Golgi trafficking, transport from the Golgi elements to the plasma membrane involved mobile transport containers in all differentiation stages. These findings indicate that ER-to-Golgi trafficking in adult skeletal myofibers does not involve long-distance moving membrane carriers as occurs in other mammalian cell types.

  17. ARM CLASIC ER2 CRS/EDOP

    SciTech Connect

    Gerald Heymsfield

    2010-12-20

    Data was taken with the NASA ER-2 aircraft with the Cloud Radar System and other instruments in conjunction with the DOE ARM CLASIC field campaign. The flights were near the SGP site in north Central Oklahoma and targeted small developing convection. The CRS is a 94 GHz nadir pointing Doppler radar. Also on board the ER-2 was the Cloud Physics Lidar (CPL). Seven science flights were conducted but the weather conditions did not cooperate in that there was neither developing convection, or there was heavy rain.

  18. Structural Determination of Certain Novel ER Complexes

    DTIC Science & Technology

    2005-09-01

    and Parker, T. M. (1992). Hydrophobicity-induced pK shifts in elastin protein-based polymers . Biopolymers 32, 373-379. Webb, P., Nguyen, P., and...between the aligned H12 from different complex struc- Chemicals, Materials, and Plasmids tures (OHT-ER and GW-ER) were calculated using a python script...buffer consisting of 1.5%-2% ethylene were used. 100 nM of GW7604 were added to the cells 18-24 hr imine polymer , 100 mM trisodium citrate (pH 5.6-5.7

  19. Caries inhibition potential of Er:YAG and Er:YSGG laser radiation

    NASA Astrophysics Data System (ADS)

    Fried, Daniel; Featherstone, John D. B.; Visuri, Steven R.; Seka, Wolf D.; Walsh, Joseph T., Jr.

    1996-04-01

    Dental hard tissues can be ablated efficiency by (lambda) equals 3 micrometers laser irradiation with minimal subsurface thermal damage. However, the potential of lasers operating in the region of the infrared for caries preventive treatments has not been investigated. In this study, the caries inhibition potential of Er:YAG ((lambda) equals 2.94 micrometers ) and Er:YSGG ((lambda) equals 2.79 micrometers ) laser radiation on dental enamel was evaluated at various irradiation intensities. Pulsed IR radiometry and scanning electron microscopy (SEM) were used to measure the time-resolved surface temperatures during laser irradiation and to detect changes in the surface morphology. The magnitude and temporal evolution of the surface temperature during multiple pulse irradiation of the tissue was dependent on the wavelength, irradiation intensity, and the number of laser pulses. Radiometry and SEM micrographs indicated that ablation was initiated at temperatures of approximately 300 degree(s)C for Er:YAG and 800 degree(s)C for Er:YSGG laser irradiation, well below the melting and vaporization temperatures of the carbonated hydroxyapatite mineral component (m.p. equals 1200 degree(s)C). Nevertheless, there was marked caries inhibition for irradiation intensities below those temperature thresholds, notably 60% and 40% inhibition was achieved after Er:YSGG and Er:YAG laser irradiation, respectively. These results indicate that the Er:YSGG laser can be used effectively for both preventive dental treatments and for hard tissue removal.

  20. Transcriptional Profiling of Chondrodysplasia Growth Plate Cartilage Reveals Adaptive ER-Stress Networks That Allow Survival but Disrupt Hypertrophy

    PubMed Central

    Cameron, Trevor L.; Bell, Katrina M.; Tatarczuch, Liliana; Mackie, Eleanor J.; Rajpar, M. Helen; McDermott, Ben T.; Boot-Handford, Raymond P.; Bateman, John F.

    2011-01-01

    Metaphyseal chondrodysplasia, Schmid type (MCDS) is characterized by mild short stature and growth plate hypertrophic zone expansion, and caused by collagen X mutations. We recently demonstrated the central importance of ER stress in the pathology of MCDS by recapitulating the disease phenotype by expressing misfolding forms of collagen X (Schmid) or thyroglobulin (Cog) in the hypertrophic zone. Here we characterize the Schmid and Cog ER stress signaling networks by transcriptional profiling of microdissected mutant and wildtype hypertrophic zones. Both models displayed similar unfolded protein responses (UPRs), involving activation of canonical ER stress sensors and upregulation of their downstream targets, including molecular chaperones, foldases, and ER-associated degradation machinery. Also upregulated were the emerging UPR regulators Wfs1 and Syvn1, recently identified UPR components including Armet and Creld2, and genes not previously implicated in ER stress such as Steap1 and Fgf21. Despite upregulation of the Chop/Cebpb pathway, apoptosis was not increased in mutant hypertrophic zones. Ultrastructural analysis of mutant growth plates revealed ER stress and disrupted chondrocyte maturation throughout mutant hypertrophic zones. This disruption was defined by profiling the expression of wildtype growth plate zone gene signatures in the mutant hypertrophic zones. Hypertrophic zone gene upregulation and proliferative zone gene downregulation were both inhibited in Schmid hypertrophic zones, resulting in the persistence of a proliferative chondrocyte-like expression profile in ER-stressed Schmid chondrocytes. Our findings provide a transcriptional map of two chondrocyte UPR gene networks in vivo, and define the consequences of UPR activation for the adaptation, differentiation, and survival of chondrocytes experiencing ER stress during hypertrophy. Thus they provide important insights into ER stress signaling and its impact on cartilage pathophysiology. PMID

  1. Transcriptional profiling of chondrodysplasia growth plate cartilage reveals adaptive ER-stress networks that allow survival but disrupt hypertrophy.

    PubMed

    Cameron, Trevor L; Bell, Katrina M; Tatarczuch, Liliana; Mackie, Eleanor J; Rajpar, M Helen; McDermott, Ben T; Boot-Handford, Raymond P; Bateman, John F

    2011-01-01

    Metaphyseal chondrodysplasia, Schmid type (MCDS) is characterized by mild short stature and growth plate hypertrophic zone expansion, and caused by collagen X mutations. We recently demonstrated the central importance of ER stress in the pathology of MCDS by recapitulating the disease phenotype by expressing misfolding forms of collagen X (Schmid) or thyroglobulin (Cog) in the hypertrophic zone. Here we characterize the Schmid and Cog ER stress signaling networks by transcriptional profiling of microdissected mutant and wildtype hypertrophic zones. Both models displayed similar unfolded protein responses (UPRs), involving activation of canonical ER stress sensors and upregulation of their downstream targets, including molecular chaperones, foldases, and ER-associated degradation machinery. Also upregulated were the emerging UPR regulators Wfs1 and Syvn1, recently identified UPR components including Armet and Creld2, and genes not previously implicated in ER stress such as Steap1 and Fgf21. Despite upregulation of the Chop/Cebpb pathway, apoptosis was not increased in mutant hypertrophic zones. Ultrastructural analysis of mutant growth plates revealed ER stress and disrupted chondrocyte maturation throughout mutant hypertrophic zones. This disruption was defined by profiling the expression of wildtype growth plate zone gene signatures in the mutant hypertrophic zones. Hypertrophic zone gene upregulation and proliferative zone gene downregulation were both inhibited in Schmid hypertrophic zones, resulting in the persistence of a proliferative chondrocyte-like expression profile in ER-stressed Schmid chondrocytes. Our findings provide a transcriptional map of two chondrocyte UPR gene networks in vivo, and define the consequences of UPR activation for the adaptation, differentiation, and survival of chondrocytes experiencing ER stress during hypertrophy. Thus they provide important insights into ER stress signaling and its impact on cartilage pathophysiology.

  2. GSK-3β-dependent downregulation of γ-taxilin and αNAC merge to regulate ER stress responses

    PubMed Central

    Hotokezaka, Y; Katayama, I; van Leyen, K; Nakamura, T

    2015-01-01

    The signaling pathway leading to the endoplasmic reticulum (ER) stress responses has not been fully elucidated. Here we showed that glycogen synthase kinase-3β (GSK-3β)-dependent downregulation of γ-taxilin and nascent polypeptide-associated complex α-subunit (αNAC) mediates hypoxia-induced unfolded protein responses (UPRs) and the subsequent apoptotic and autophagic pathways. The degradation of γ-taxilin or αNAC was sufficient to initiate UPRs in normoxic cells. However, the ER stress signaling pathways initiated by γ-taxilin or αNAC were distinct, triggering different ER stress sensors and activating different downstream pathways. Hypoxia caused GSK-3β-dependent tau hyperphosphorylation and cleavage in neuronal cells, but γ-taxilin ablation induced tau hyperphosphorylation alone and αNAC ablation induced neither changes. Notably, downregulation of γ-taxilin and αNAC occurs in the brain of patients with Alzheimer's disease. These results suggest that GSK-3β-dependent downregulation of γ-taxilin and αNAC, which differently activate the UPRs, merge to regulate hypoxia-induced ER stress responses and provide a new insight into the pathogenesis of neurodegenerative diseases. PMID:25880086

  3. The ER-Membrane Transport System Is Critical for Intercellular Trafficking of the NSm Movement Protein and Tomato Spotted Wilt Tospovirus

    PubMed Central

    Feng, Zhike; Xue, Fan; Xu, Min; Chen, Xiaojiao; Zhao, Wenyang; Garcia-Murria, Maria J.; Mingarro, Ismael; Liu, Yong; Huang, Ying; Jiang, Lei; Zhu, Min; Tao, Xiaorong

    2016-01-01

    Plant viruses move through plasmodesmata to infect new cells. The plant endoplasmic reticulum (ER) is interconnected among cells via the ER desmotubule in the plasmodesma across the cell wall, forming a continuous ER network throughout the entire plant. This ER continuity is unique to plants and has been postulated to serve as a platform for the intercellular trafficking of macromolecules. In the present study, the contribution of the plant ER membrane transport system to the intercellular trafficking of the NSm movement protein and Tomato spotted wilt tospovirus (TSWV) is investigated. We showed that TSWV NSm is physically associated with the ER membrane in Nicotiana benthamiana plants. An NSm-GFP fusion protein transiently expressed in single leaf cells was trafficked into neighboring cells. Mutations in NSm that impaired its association with the ER or caused its mis-localization to other subcellular sites inhibited cell-to-cell trafficking. Pharmacological disruption of the ER network severely inhibited NSm-GFP trafficking but not GFP diffusion. In the Arabidopsis thaliana mutant rhd3 with an impaired ER network, NSm-GFP trafficking was significantly reduced, whereas GFP diffusion was not affected. We also showed that the ER-to-Golgi secretion pathway and the cytoskeleton transport systems were not involved in the intercellular trafficking of TSWV NSm. Importantly, TSWV cell-to-cell spread was delayed in the ER-defective rhd3 mutant, and this reduced viral infection was not due to reduced replication. On the basis of robust biochemical, cellular and genetic analysis, we established that the ER membrane transport system serves as an important direct route for intercellular trafficking of NSm and TSWV. PMID:26863622

  4. Low temperature properties of some Er-rich intermetallic compounds

    SciTech Connect

    K.A. Gshneidner,jr; A.O. Pecharsky; L.Hale; V.K. Pecharsky

    2004-09-30

    The low temperature volumetric heat capacity ({approx}3.5 to 350 K) and magnetic susceptibility ({approx}4 to 320 K) of Er{sub 3}Rh, Er{sub 3}Ir, Er{sub 3}Pt, Er{sub 2}Al, and Er{sub 2}Sn have been measured. All of the compounds order antiferromagnetically (or ferrimagnetically), and most exhibit more than one magnetic ordering transition. The volumetric heat capacities in general are smaller than those of the prototype magnetic regenerator materials, except for Er{sub 3}Ir in the 12 to 14 K temperature range.

  5. Creating Smart-er Cities: An Overview

    ERIC Educational Resources Information Center

    Allwinkle, Sam; Cruickshank, Peter

    2011-01-01

    The following offers an overview of what it means for cities to be "smart." It draws the supporting definitions and critical insights into smart cities from a series of papers presented at the 2009 Trans-national Conference on Creating Smart(er) Cities. What the papers all have in common is their desire to overcome the all too often…

  6. The QuEChERS revolution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The technique of QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) is only 7 years old, yet it is revolutionizing the manner in which multiresidue, multiclass pesticide analysis (and perhaps beyond) is performed. Columnist Ron Majors sits down with inventors Steve Lehotay and Michelangelo An...

  7. Cytosolic N-terminal arginine-based signals together with a luminal signal target a type II membrane protein to the plant ER

    PubMed Central

    2009-01-01

    Background In eukaryotic cells, the membrane compartments that constitute the exocytic pathway are traversed by a constant flow of lipids and proteins. This is particularly true for the endoplasmic reticulum (ER), the main "gateway of the secretory pathway", where biosynthesis of sterols, lipids, membrane-bound and soluble proteins, and glycoproteins occurs. Maintenance of the resident proteins in this compartment implies they have to be distinguished from the secretory cargo. To this end, they must possess specific ER localization determinants to prevent their exit from the ER, and/or to interact with receptors responsible for their retrieval from the Golgi apparatus. Very few information is available about the signal(s) involved in the retention of membrane type II protein in the ER but it is generally accepted that sorting of ER type II cargo membrane proteins depends on motifs mainly located in their cytosolic tails. Results Here, using Arabidopsis glucosidase I as a model, we have identified two types of signals sufficient for the location of a type II membrane protein in the ER. A first signal is located in the luminal domain, while a second signal corresponds to a short amino acid sequence located in the cytosolic tail of the membrane protein. The cytosolic tail contains at its N-terminal end four arginine residues constitutive of three di-arginine motifs (RR, RXR or RXXR) independently sufficient to confer ER localization. Interestingly, when only one di-arginine motif is present, fusion proteins are located both in the ER and in mobile punctate structures, distinct but close to Golgi bodies. Soluble and membrane ER protein markers are excluded from these punctate structures, which also do not colocalize with an ER-exit-site marker. It is hypothesized they correspond to sites involved in Golgi to ER retrotransport. Conclusion Altogether, these results clearly show that cytosolic and luminal signals responsible for ER retention could coexist in a same type

  8. Iron depletion increases manganese uptake and potentiates apoptosis through ER stress

    PubMed Central

    Seo, Young Ah; Li, Yuan; Wessling-Resnick, Marianne

    2013-01-01

    Iron deficiency is a risk factor for manganese (Mn) accumulation. Excess Mn promotes neurotoxicity but the mechanisms involved and whether iron depletion might affect these pathways is unknown. To study Mn intoxication in vivo, iron deficient and control rats were intranasally instilled with 60 mg MnCl2/kg over 3 weeks. TUNEL staining of olfactory tissue revealed that Mn exposure induced apoptosis and that iron deficiency potentiated this effect. In vitro studies using the dopaminergic SH-SY5Y cell line confirmed that Mn-induced apoptosis was enhanced by iron depletion using the iron chelator desferrioxamine. Mn has been reported to induce apoptosis through endoplasmic reticulum stress. In SH-SY5Y cells, Mn exposure induced the ER stress genes glucose regulated protein 94 (GRP94) and C/EBP homologous protein (CHOP). Increased phosphorylation of the eukaryotic translation initiation factor 2α (phospho-eIF2α) was also observed. These effects were accompanied by the activation of ER resident enzyme caspase-12, and the downstream apoptotic effector caspase-3 was also activated. All of the Mn-induced responses were enhanced by DFO treatment. Inhibitors of ER stress and caspases significantly blocked Mn-induced apoptosis and its potentiation by DFO, indicating that ER stress and subsequent caspase activation underlie cell death. Taken together, these data reveal that Mn induces neuronal cell death through ER stress and the UPR response pathway and that this apoptotic effect is potentiated by iron deficiency most likely through upregulation of DMT1. PMID:23764342

  9. Dissection of local Ca(2+) signals inside cytosol by ER-targeted Ca(2+) indicator.

    PubMed

    Niwa, Fumihiro; Sakuragi, Shigeo; Kobayashi, Ayana; Takagi, Shin; Oda, Yoichi; Bannai, Hiroko; Mikoshiba, Katsuhiko

    2016-10-07

    Calcium (Ca(2+)) is a versatile intracellular second messenger that operates in various signaling pathways leading to multiple biological outputs. The diversity of spatiotemporal patterns of Ca(2+) signals, generated by the coordination of Ca(2+) influx from the extracellular space and Ca(2+) release from the intracellular Ca(2+) store the endoplasmic reticulum (ER), is considered to underlie the diversity of biological outputs caused by a single signaling molecule. However, such Ca(2+) signaling diversity has not been well described because of technical limitations. Here, we describe a new method to report Ca(2+) signals at subcellular resolution. We report that OER-GCaMP6f, a genetically encoded Ca(2+) indicator (GECI) targeted to the outer ER membrane, can monitor Ca(2+) release from the ER at higher spatiotemporal resolution than conventional GCaMP6f. OER-GCaMP6f was used for in vivo Ca(2+) imaging of C. elegans. We also found that the spontaneous Ca(2+) elevation in cultured astrocytes reported by OER-GCaMP6f showed a distinct spatiotemporal pattern from that monitored by plasma membrane-targeted GCaMP6f (Lck-GCaMP6f); less frequent Ca(2+) signal was detected by OER-GCaMP6f, in spite of the fact that Ca(2+) release from the ER plays important roles in astrocytes. These findings suggest that targeting of GECIs to the ER outer membrane enables sensitive detection of Ca(2+) release from the ER at subcellular resolution, avoiding the diffusion of GECI and Ca(2+). Our results indicate that Ca(2+) imaging with OER-GCaMP6f in combination with Lck-GCaMP6f can contribute to describing the diversity of Ca(2+) signals, by enabling dissection of Ca(2+) signals at subcellular resolution.

  10. E platinum, a newly synthesized platinum compound, induces apoptosis through ROS-triggered ER stress in gastric carcinoma cells.

    PubMed

    Wang, Xiaoping; Guo, Qinglong; Tao, Lei; Zhao, Li; Chen, Yan; An, Teng; Chen, Zhen; Fu, Rong

    2017-01-01

    Gastric cancer (GC) is still one of the leading causes of death in cancer-related diseases. In this study, we aimed to investigate the antitumor effect of E Platinum, a newly platinum-based chemotherapeutic agent bearing the basic structure of Oxaliplatin, in a variety of gastric carcinoma cells and the underlying mechanisms. We demonstrated that E Platinum significantly induced apoptosis in gastric cancer cells via mitochondrial apoptotic pathway as a result of increased reactive oxygen species (ROS). We also found that E Platinum enhanced Ca(2+) flux out from the endoplasmic reticulum by increasing the protein expression of IP3R type 1 (IP3R1) and decreasing the expression of ERp44. Dysfunction of Ca(2+) homeostasis in endoplasmic reticulum (ER) leads to accumulation of unfolded proteins and ER stress. Mechanically, E Platinum increased ER stress associated protein expression such as GRP78, p-PERK, p-eIF2α, ATF4, and CHOP. However, knocking down CHOP reversed E Platinum-induced apoptosis by blocking mitochondrial apoptotic pathway. Furthermore, 10 mg/kg of E Platinum significantly suppressed BGC-823 tumor growth in vivo without toxicity, which correlated with induction of apoptosis and expression of ER stress related proteins in tumor tissues. Taken together, E Platinum inhibited tumor growth and induced apoptosis by ROS-mediated ER stress activation both in vitro and in vivo. Our study indicated that E Platinum may be a potential and effective treatment for gastric cancer in clinical. © 2016 Wiley Periodicals, Inc.

  11. Interaction of Er{sup 3+} ions in Er-doped calcium - niobium - gallium garnet crystals

    SciTech Connect

    Malov, A V; Popov, A V; Ryabochkina, P A; Bol'shakov, E V

    2010-08-03

    The processes of nonradiative energy transfer in calcium - niobium - gallium garnet (CNGG) crystals doped with Er{sup 3+} ions are studied. It is found that the energy of erbium ions in the Er:CNGG crystal with the erbium atomic concentrations C{sub Er}=6% and 11% is transferred via the nonradiative co-operative processes {sup 4}I{sub 11/2{yields}} {sup 4}I{sub 15/2}, {sup 4}I{sub 11/2{yields}} {sup 4}F{sub 7/2}, {sup 4}I{sub 11/2{yields}} {sup 4}I{sub 15/2}, {sup 4}I{sub 13/2{yields}} {sup 4}F{sub 9/2}; and {sup 4}I{sub 13/2{yields}} {sup 4}I{sub 15/2}, {sup 4}I{sub 13/2{yields}} {sup 4}I{sub 9/2}, whose efficiency increases with increasing intensity of exciting radiation. It is shown that the cross-relaxation processes {sup 4}S{sub 3/2{yields}}{sup 4}I{sub 9/2}, {sup 4}I{sub 15/2{yields}}{sup 4}I{sub 13/2}, whose intensity depends on the concentration of Er{sup 3+} ions, are characteristic for Er:CNGG crystals with the Er atomic concentration above 1%. (active media)

  12. Spectroscopic properties of Er3+, Yb3 + and Er3 + /Yb3+ doped metaphosphate glasses.

    PubMed

    Speghini, A; Francini, R; Martinez, A; Tavernese, M; Bettinell, M

    2001-09-01

    The absorption and emission spectroscopies of Er3+ doped and Er3+/Yb3+ codoped Ca(PO3)2, Sr(PO3)2 and Ba(PO3)2 glasses have been studied. From the Judd-Ofelt intensity parameters, the spontaneous emission probabilities of some relevant transitions and the radiative lifetimes of several excited states of Er3+ have been calculated. The decay curves of the Er3+ emission at 1.5 microm have been measured at different temperatures. The data have been fitted using a stretched exponential function and the obtained experimental lifetimes have been compared with the calculated radiative lifetimes. The difference between the experimental and calculated lifetimes is attributed to the presence of traces of OH groups in the host glasses. The absolute OH content in some glasses has been determined from the infrared spectra. The emission spectra at 1.5 microm of the Er3+ ion in the codoped glasses have been measured at different temperatures. The integrated emission intensities decrease significantly on passing from room temperature to 13 K, suggesting a temperature dependence of the rate of the energy transfer process between Yb3+ and Er3+.

  13. Varicella-Zoster Virus Infectious Cycle: ER Stress, Autophagic Flux, and Amphisome-Mediated Trafficking

    PubMed Central

    Grose, Charles; Buckingham, Erin M.; Carpenter, John E.; Kunkel, Jeremy P.

    2016-01-01

    Varicella-zoster virus (VZV) induces abundant autophagy. Of the nine human herpesviruses, the VZV genome is the smallest (~124 kbp), lacking any known inhibitors of autophagy, such as the herpes simplex virus ICP34.5 neurovirulence gene. Therefore, this review assesses the evidence for VZV-induced cellular stress, endoplasmic-reticulum-associated degradation (ERAD), and autophagic flux during the VZV infectious cycle. Even though VZV is difficult to propagate in cell culture, the biosynthesis of the both N- and O-linked viral glycoproteins was found to be abundant. In turn, this biosynthesis provided evidence of endoplasmic reticulum (ER) stress, including a greatly enlarged ER and a greatly diminished production of cellular glycoproteins. Other signs of ER stress following VZV infection included detection of the alternatively spliced higher-molecular-weight form of XBP1 as well as CHOP. VZV infection in cultured cells leads to abundant autophagosome production, as was visualized by the detection of the microtubule-associated protein 1 light chain 3-II (LC3-II). The degree of autophagy induced by VZV infection is comparable to that induced in uninfected cells by serum starvation. The inhibition of autophagic flux by chemicals such as 3-methyladenine or ATG5 siRNA, followed by diminished virus spread and titers, has been observed. Since the latter observation pointed to the virus assembly/trafficking compartments, we purified VZ virions by ultracentrifugation and examined the virion fraction for components of the autophagy pathway. We detected LC3-II protein (an autophagy marker) as well as Rab11 protein, a component of the endosomal pathway. We also observed that the virion-containing vesicles were single-walled; thus, they are not autophagosomes. These results suggested that some VZ virions after secondary envelopment were transported to the outer cell membrane in a vesicle derived from both the autophagy and endosomal pathways, such as an amphisome. Thus, these

  14. 155. Credit ER. Hand cleaning and trimming of Coleman canal ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    155. Credit ER. Hand cleaning and trimming of Coleman canal after excavation by steam shovel. (ER, v. 64 1911 p. 701). - Battle Creek Hydroelectric System, Battle Creek & Tributaries, Red Bluff, Tehama County, CA

  15. ER Consolidated Qtrly Rpt_April-June 2016_October 2016

    SciTech Connect

    Cochran, John R.

    2016-10-01

    This Environmental Restoration Operations (ER) Consolidated Quarterly Report (ER Quarterly Report) provides the status of ongoing corrective action activities being implemented by Sandia National Laboratories, New Mexico (SNL/NM) for the April, May, and June 2016 quarterly reporting period.

  16. 150. Credit ER. Building reinforced concrete portion of Coleman Canal ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    150. Credit ER. Building reinforced concrete portion of Coleman Canal inverted siphon #2. Longitudinal steel reinforcing rods are visible at bottom. (ER, v. 64 1911 p. 702). - Battle Creek Hydroelectric System, Battle Creek & Tributaries, Red Bluff, Tehama County, CA

  17. PERK is required at the ER-mitochondrial contact sites to convey apoptosis after ROS-based ER stress.

    PubMed

    Verfaillie, T; Rubio, N; Garg, A D; Bultynck, G; Rizzuto, R; Decuypere, J-P; Piette, J; Linehan, C; Gupta, S; Samali, A; Agostinis, P

    2012-11-01

    Endoplasmic reticulum stress is emerging as an important modulator of different pathologies and as a mechanism contributing to cancer cell death in response to therapeutic agents. In several instances, oxidative stress and the onset of endoplasmic reticulum (ER) stress occur together; yet, the molecular events linking reactive oxygen species (ROS) to ER stress-mediated apoptosis are currently unknown. Here, we show that PERK (RNA-dependent protein kinase (PKR)-like ER kinase), a key ER stress sensor of the unfolded protein response, is uniquely enriched at the mitochondria-associated ER membranes (MAMs). PERK(-/-) cells display disturbed ER morphology and Ca(2+) signaling as well as significantly weaker ER-mitochondria contact sites. Re-expression of a kinase-dead PERK mutant but not the cytoplasmic deletion mutant of PERK in PERK(-/-) cells re-establishes ER-mitochondria juxtapositions and mitochondrial sensitization to ROS-mediated stress. In contrast to the canonical ER stressor thapsigargin, during ROS-mediated ER stress, PERK contributes to apoptosis twofold by sustaining the levels of pro-apoptotic C/EBP homologous protein (CHOP) and by facilitating the propagation of ROS signals between the ER and mitochondria through its tethering function. Hence, this study reveals an unprecedented role of PERK as a MAMs component required to maintain the ER-mitochondria juxtapositions and propel ROS-mediated mitochondrial apoptosis. Furthermore, it suggests that loss of PERK may cause defects in cell death sensitivity in pathological conditions linked to ROS-mediated ER stress.

  18. Vesicular transport of progeny parvovirus particles through ER and Golgi regulates maturation and cytolysis.

    PubMed

    Bär, Séverine; Rommelaere, Jean; Nüesch, Jürg P F

    2013-09-01

    Progeny particles of non-enveloped lytic parvoviruses were previously shown to be actively transported to the cell periphery through vesicles in a gelsolin-dependent manner. This process involves rearrangement and destruction of actin filaments, while microtubules become protected throughout the infection. Here the focus is on the intracellular egress pathway, as well as its impact on the properties and release of progeny virions. By colocalization with cellular marker proteins and specific modulation of the pathways through over-expression of variant effector genes transduced by recombinant adeno-associated virus vectors, we show that progeny PV particles become engulfed into COPII-vesicles in the endoplasmic reticulum (ER) and are transported through the Golgi to the plasma membrane. Besides known factors like sar1, sec24, rab1, the ERM family proteins, radixin and moesin play (an) essential role(s) in the formation/loading and targeting of virus-containing COPII-vesicles. These proteins also contribute to the transport through ER and Golgi of the well described analogue of cellular proteins, the secreted Gaussia luciferase in absence of virus infection. It is therefore likely that radixin and moesin also serve for a more general function in cellular exocytosis. Finally, parvovirus egress via ER and Golgi appears to be necessary for virions to gain full infectivity through post-assembly modifications (e.g. phosphorylation). While not being absolutely required for cytolysis and progeny virus release, vesicular transport of parvoviruses through ER and Golgi significantly accelerates these processes pointing to a regulatory role of this transport pathway.

  19. Restoration of autophagy alleviates hepatic ER stress and impaired insulin signalling transduction in high fructose-fed male mice.

    PubMed

    Wang, Hao; Sun, Ruo-Qiong; Zeng, Xiao-Yi; Zhou, Xiu; Li, Songpei; Jo, Eunjung; Molero, Juan C; Ye, Ji-Ming

    2015-01-01

    High-carbohydrate (mainly fructose) consumption is a major dietary factor for hepatic insulin resistance, involving endoplasmic reticulum (ER) stress and lipid accumulation. Because autophagy has been implicated in ER stress, the present study investigated the role of autophagy in high-fructose (HFru) diet-induced hepatic ER stress and insulin resistance in male C57BL/6J mice. The results show that chronic HFru feeding induced glucose intolerance and impaired insulin signaling transduction in the liver, associated with ER stress and the accumulation of lipids. Intriguingly, hepatic autophagy was suppressed as a result of activation of mammalian target of rapamycin. The suppressed autophagy was detected within 6 hours after HFru feeding along with activation of both inositol-requiring enzyme 1 and protein kinase RNA-like endoplasmic reticulum kinase pathways. These events occurred prior to lipid accumulation or lipogenesis and were sufficient to blunt insulin signaling transduction with activation of c-Jun N-terminal kinase/inhibitory-κB kinase and serine phosphorylation of insulin receptor substrate 1. The stimulation of autophagy attenuated ER stress- and c-Jun N-terminal kinase/inhibitory-κB kinase-associated impairment in insulin signaling transduction in a mammalian target of rapamycin -independent manner. Taken together, our data suggest that restoration of autophagy functions disrupted by fructose is able to alleviate ER stress and improve insulin signaling transduction.

  20. Fis1 and Bap31 bridge the mitochondria-ER interface to establish a platform for apoptosis induction.

    PubMed

    Iwasawa, Ryota; Mahul-Mellier, Anne-Laure; Datler, Christoph; Pazarentzos, Evangelos; Grimm, Stefan

    2011-02-02

    The mitochondria and the endoplasmic reticulum (ER) are two organelles that critically contribute to apoptosis induction. While it is established that they communicate, how cell death signals are transmitted from the mitochondria to the ER is unknown. Here, we show that the mitochondrial fission protein Fission 1 homologue (Fis1) conveys an apoptosis signal from the mitochondria to the ER by interacting with Bap31 at the ER and facilitating its cleavage into the pro-apoptotic p20Bap31. Exogenous apoptosis inducers likewise use this signalling route and induce the procession of Bap31. Moreover, we show that the recruitment of procaspase-8 to the Fis1-Bap31 platform is an early event during apoptosis induction. The association of procaspase-8 with the Fis1-Bap31 complex is dependent on the variant of death effector domain (vDED) in Bap31 and is required for the activation of procaspase-8. This signalling pathway establishes a feedback loop by releasing Ca(2+) from the ER that activates the mitochondria for apoptosis. Hence, the Fis1-Bap31 complex (ARCosome) that spans the mitochondria-ER interface serves as a platform to activate the initiator procaspase-8, and thereby bridges two critical organelles for apoptosis signalling.

  1. Synthesis, characterization, and photoluminescence of Er2O3-Er2SO2 nanoparticles on reduced graphene oxide.

    PubMed

    Kalugin, Nikolai G; Roy, Aaron; Artyushkova, Kateryna; Serov, Alexey

    2017-03-30

    Thermal reduction of erbium nitrate and S-doped reduced graphene oxide (rGO) mixture resulted in the formation of small (~3-18 nm-sized) Er2O3-Er2SO2 nanoparticles with a high degree of surface coverage on the reduced graphene oxide support. The morphology, structure, and the chemical composition of the synthesized nanoparticles have been studied by scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and by optical spectroscopies. The rGO-supported Er2O3-Er2SO2 nanoparticles (Er2O3-Er2SO2 /rGO) demonstrate sufficiently strong light emission (luminescence and upconversion) in the visible and near-infrared range via intra-4f Er3+ optical transitions. The reported synthetic approach demonstrates a novel method for synthesizing Er-containing nanoparticles for sensor applications.

  2. Targeting autophagy enhances sorafenib lethality for hepatocellular carcinoma via ER stress-related apoptosis.

    PubMed

    Shi, Ying-Hong; Ding, Zhen-Bin; Zhou, Jian; Hui, Bo; Shi, Guo-Ming; Ke, Ai-Wu; Wang, Xiao-Ying; Dai, Zhi; Peng, Yuan-Fei; Gu, Cheng-Yu; Qiu, Shuang-Jian; Fan, Jia

    2011-10-01

    Sorafenib, a potent multikinase inhibitor, has been recognized as the standard systemic treatment for patients with advanced hepatocellular carcinoma (HCC). However, the direct functional mechanism of tumor lethality mediated by sorafenib remains to be fully characterized, and the precise mechanisms of drug resistance are largely unknown. Here, we showed sorafenib induced both apoptosis and autophagy in human HCC cells through a mechanism that involved endoplasmic reticulum (ER) stress and was independent of the MEK1/2-ERK1/2 pathway. Upregulation of IRE1 signals from sorafenib-induced ER stress was critical for the induction of autophagy. Moreover, autophagy activation alleviated the ER stress-induced cell death. Inhibition of autophagy using either pharmacological inhibitors or essential autophagy gene knockdown enhanced cell death in sorafenib treated HCC cell lines. Critically, the combination of sorafenib with the autophagy inhibitor chloroquine produced more pronounced tumor suppression in HCC both in vivo and in vitro. These findings indicated that both ER stress and autophagy were involved in the cell death evoked by sorafenib in HCC cells. The combination of autophagy modulation and molecular targeted therapy is a promising therapeutic strategy in treatment of HCC.

  3. IRS1 deficiency protects β-cells against ER stress-induced apoptosis by modulating sXBP-1 stability and protein translation

    PubMed Central

    Takatani, Tomozumi; Shirakawa, Jun; Roe, Michael W.; Leech, Colin A.; Maier, Bernhard F.; Mirmira, Raghavendra G.; Kulkarni, Rohit N.

    2016-01-01

    Endoplasmic reticulum (ER) stress is among several pathological features that underlie β-cell failure in the development of type 1 and type 2 diabetes. Adaptor proteins in the insulin/insulin-like-growth factor-1 signaling pathways, such as insulin receptor substrate-1 (IRS1) and IRS2, differentially impact β-cell survival but the underlying mechanisms remain unclear. Here we report that β-cells deficient in IRS1 (IRS1KO) are resistant, while IRS2 deficiency (IRS2KO) makes them susceptible to ER stress-mediated apoptosis. IRS1KOs exhibited low nuclear accumulation of spliced XBP-1 due to its poor stability, in contrast to elevated accumulation in IRS2KO. The reduced nuclear accumulation in IRS1KO was due to protein instability of Xbp1 secondary to proteasomal degradation. IRS1KO also demonstrated an attenuation in their general translation status in response to ER stress revealed by polyribosomal profiling. Phosphorylation of eEF2 was dramatically increased in IRS1KO enabling the β-cells to adapt to ER stress by blocking translation. Furthermore, significantly high ER calcium (Ca2+) was detected in IRS1KO β-cells even upon induction of ER stress. These observations suggest that IRS1 could be a therapeutic target for β-cell protection against ER stress-mediated cell death by modulating XBP-1 stability, protein synthesis, and Ca2+ storage in the ER. PMID:27378176

  4. SYP73 Anchors the ER to the Actin Cytoskeleton for Maintenance of ER Integrity and Streaming in Arabidopsis.

    PubMed

    Cao, Pengfei; Renna, Luciana; Stefano, Giovanni; Brandizzi, Federica

    2016-12-05

    The endoplasmic reticulum (ER) is an essential organelle that spreads throughout the cytoplasm as one interconnected network of narrow tubules and dilated cisternae that enclose a single lumen. The ER network undergoes extensive remodeling, which critically depends on membrane-cytoskeleton interactions [1]. In plants, the ER is also highly mobile, and its streaming contributes significantly to the movement of other organelles [2, 3]. The remodeling and motility of the plant ER rely mainly on actin [4] and to a minor extent on microtubules [5]. Although a three-way interaction between the ER, cytosolic myosin-XI, and F-actin mediates the plant ER streaming [6], the mechanisms underlying stable interaction of the ER membrane with actin are unknown. Early electron microscopy studies suggested a direct attachment of the plant ER with actin filaments [7, 8], but it is plausible that yet-unknown proteins facilitate anchoring of the ER membrane with the cytoskeleton. We demonstrate here that SYP73, a member of the plant Syp7 subgroup of SNARE proteins [9] containing actin-binding domains, is a novel ER membrane-associated actin-binding protein. We show that overexpression of SYP73 causes a striking rearrangement of the ER over actin and that, similar to mutations of myosin-XI [4, 10, 11], loss of SYP73 reduces ER streaming and affects overall ER network morphology and plant growth. We propose a model for plant ER remodeling whereby the dynamic rearrangement and streaming of the ER network depend on the propelling action of myosin-XI over actin coupled with a SYP73-mediated bridging, which dynamically anchors the ER membrane with actin filaments.

  5. ER-12-1 completion report

    SciTech Connect

    Russell, C.E.; Gillespie, D.; Cole, J.C.; Drellack, S.L.

    1996-12-01

    The objective of drillhole ER-12-1 was to determine the hydrogeology of paleozoic carbonate rocks and of the Eleana Formation, a regional aquitard, in an area potentially downgradient from underground nuclear testing conducted in nearby Rainier Mesa. This objective was addressed through the drilling of well ER-12-1 at N886,640.26 E640,538.85 Nevada Central Coordinates. Drilling of the 1094 m (3588 ft) well began on July 19, 1991 and was completed on October 17, 1991. Drilling problems included hole deviation and hole instability that prevented the timely completion of this borehole. Drilling methods used include rotary tri-cone and rotary hammer drilling with conventional and reverse circulation using air/water, air/foam (Davis mix), and bentonite mud. Geologic cuttings and geophysical logs were obtained from the well. The rocks penetrated by the ER-12-1 drillhole are a complex assemblage of Silurian, Devonian, and Mississippian sedimentary rocks that are bounded by numerous faults that show substantial stratigraphic offset. The final 7.3 m (24 ft) of this hole penetrated an unusual intrusive rock of Cretaceous age. The geology of this borehole was substantially different from that expected, with the Tongue Wash Fault encountered at a much shallower depth, paleozoic rocks shuffled out of stratigraphic sequence, and the presence of an altered biotite-rich microporphyritic igneous rock at the bottom of the borehole. Conodont CAI analyses and rock pyrolysis analyses indicate that the carbonate rocks in ER-12-1, as well as the intervening sheets of Eleana siltstone, have been thermally overprinted following movement on the faults that separate them. The probable source of heat for this thermal disturbance is the microporphyritic intrusion encountered at the bottom of the hole, and its age establishes that the major fault activity must have occurred prior to 102.3+0.5 Ma (middle Cretaceous).

  6. Electrorheological (ER) Fluids: A Research Needs Assessment

    DTIC Science & Technology

    1993-05-01

    control of their dynamic response to earthquakes and windstorms. The potential exists here to render nuclear power plants more resistant to earthquakes...of stress vs. strain as illustrated in Figure 2 (Gamota and Filisko 1991a). 5.9-9 T 4000 volts SHEAR 31 3000 vot STRESS or...from the National Technical Information Service, U.S. Department of Commerce. 5285 Port Royal Rd., Springfield, VA 22161, DOE’/ER/30O1 7)-. T UC-330,400

  7. ER contact sites direct late endosome transport.

    PubMed

    Wijdeven, Ruud H; Jongsma, Marlieke L M; Neefjes, Jacques; Berlin, Ilana

    2015-12-01

    Endosomes shuttle select cargoes between cellular compartments and, in doing so, maintain intracellular homeostasis and enable interactions with the extracellular space. Directionality of endosomal transport critically impinges on cargo fate, as retrograde (microtubule minus-end directed) traffic delivers vesicle contents to the lysosome for proteolysis, while the opposing anterograde (plus-end directed) movement promotes recycling and secretion. Intriguingly, the endoplasmic reticulum (ER) is emerging as a key player in spatiotemporal control of late endosome and lysosome transport, through the establishment of physical contacts with these organelles. Earlier studies have described how minus-end-directed motor proteins become discharged from vesicles engaged at such contact sites. Now, Raiborg et al. implicate ER-mediated interactions, induced by protrudin, in loading plus-end-directed motor kinesin-1 onto endosomes, thereby stimulating their transport toward the cell's periphery. In this review, we recast the prevailing concepts on bidirectional late endosome transport and discuss the emerging paradigm of inter-compartmental regulation from the ER-endosome interface viewpoint.

  8. Present statue of Japanese ERS-1 Project

    NASA Technical Reports Server (NTRS)

    Ishiwada, Yasufumi; Nemoto, Yoshiaki

    1986-01-01

    Earth Resources Satellite 1 (ERS-1) will be launched in the FY 1990 with the H-1 rocket from Tanegashima Space Center. ERS-1 will seek to firmly establish remote sensing technologies from space by using synthetic aperture radar and optical sensors, as well as primarily exploring for non-renewable resources and also monitoring for land use, agriculture, forestry, fishery, conservation of environment, prevention of disasters, and surveillance of coastal regions. ERS-1 is a joint project in which the main responsibility for the development of the mission equipment is assumed by the Agency of Industrial Science and Technology, MITI, and the Technology Research Association of Resources Remote Sensing System, while that for the satellite itself and launching rocket is assumed by the Science and Technology Agency (STA) and the National Space Development Agency (NASDA). In relation to this project, users have maintained a close working relationship with the manufacturers after submitting their requirements in 1984 on the specifications of the mission equipments. This missions parameters are outlined.

  9. Ultrastructural features of the early secretory pathway in Trichoderma reesei.

    PubMed

    Nykänen, Marko; Birch, Debra; Peterson, Robyn; Yu, Hong; Kautto, Liisa; Gryshyna, Anna; Te'o, Junior; Nevalainen, Helena

    2016-05-01

    We have systematically analysed the ultrastructure of the early secretory pathway in the Trichoderma reesei hyphae in the wild-type QM6a, cellulase-overexpressing Rut-C30 strain and a Rut-C30 transformant BV47 overexpressing a recombinant BiP1-VenusYFP fusion protein with an endoplasmic reticulum (ER) retention signal. The hyphae were studied after 24 h of growth using transmission electron microscopy, confocal microscopy and quantitative stereological techniques. All three strains exhibited different spatial organisation of the ER at 24 h in both a cellulase-inducing medium and a minimal medium containing glycerol as a carbon source (non-cellulase-inducing medium). The wild-type displayed a number of ER subdomains including parallel tubular/cisternal ER, ER whorls, ER-isolation membrane complexes with abundant autophagy vacuoles and dense bodies. Rut-C30 and its transformant BV47 overexpressing the BiP1-VenusYFP fusion protein also contained parallel tubular/cisternal ER, but no ER whorls; also, there were very few autophagy vacuoles and an increasing amount of punctate bodies where particularly the recombinant BiP1-VenusYFP fusion protein was localised. The early presence of distinct strain-specific features such as the dominance of ER whorls in the wild type and tub/cis ER in Rut-C30 suggests that these are inherent traits and not solely a result of cellular response mechanisms by the high secreting mutant to protein overload.

  10. The unfolded protein response (UPR) pathway in Cryptococcus

    PubMed Central

    Cheon, Seon Ah; Jung, Kwang-Woo; Bahn, Yong-Sun; Kang, Hyun Ah

    2014-01-01

    Unique and evolutionarily conserved signaling pathways allow an organism to sense, respond to, and adapt to internal and external environmental cues at its biological niche. In eukaryotic cells, the unfolded protein response (UPR) pathway regulates endoplasmic reticulum (ER) homeostasis upon exposure to environmental changes causing ER stress. The UPR pathway of Cryptococcus neoformans, an opportunistic fungal pathogen, which causes life-threatening meningoencephalitis in immunocompromised individuals, consists of the evolutionarily conserved Ire1 kinase, a unique bZIP transcription factor, Hxl1, and the ER-resident molecular chaperone Kar2/BiP. Although the Cryptococcus UPR pathway regulates ER stress, antifungal drug resistance, and virulence in an Ire1/Hxl1-dependent manner, Ire1 has Hxl1-independent roles in capsule biosynthesis and thermotolerance. In this review, we highlight the conserved and unique features of the Cryptococcus UPR pathway compared with other fungal UPR systems and its importance in the pathogenesis of cryptococcosis and discuss future challenges in this field. PMID:24504058

  11. Optical properties of Er3 +-doped oxyfluoride glasses

    NASA Astrophysics Data System (ADS)

    Feng, Li; Wu, Yinsu

    2016-02-01

    Er3 +-singly doped and Er3 +/Yb3 +-codoped 50SiO2-(50 - x)BaF2-xZnF2(SBZx) oxyfluoride glasses are prepared and the optical properties of Er3 +-singly doped glasses are investigated by using the Judd-Ofelt theory. Bright green and red upconversion luminescence of Er3 +/Yb3 +-codoped glasses is obtained under 980 nm excitation. Furthermore, factors affecting this phenomenon such as glass composition, doping concentration of Er3 + and Yb3 + ions, and pump power are discussed in details.

  12. Reactive oxygen species-mediated unfolded protein response pathways in preimplantation embryos

    PubMed Central

    Ali, Ihsan; Shah, Syed Zahid Ali; Jin, Yi; Li, Zhong-Shu; Ullah, Obaid

    2017-01-01

    Excessive production of reactive oxygen species (ROS) and endoplasmic reticulum (ER) stress-mediated responses are critical to embryonic development in the challenging in vitro environment. ROS production increases during early embryonic development with the increase in protein requirements for cell survival and growth. The ER is a multifunctional cellular organelle responsible for protein folding, modification, and cellular homeostasis. ER stress is activated by a variety of factors including ROS. Such stress leads to activation of the adaptive unfolded protein response (UPR), which restores homeostasis. However, chronic stress can exceed the toleration level of the ER, resulting in cellular apoptosis. In this review, we briefly describe the generation and impact of ROS in preimplantation embryo development, the ROS-mediated activation mechanism of the UPR via the ER, and the subsequent activation of signaling pathways following ER stress in preimplantation embryos. PMID:28057903

  13. Ternary system Er-Ni-In at T=870 K

    SciTech Connect

    Dzevenko, M.; Tyvanchuk, Yu.; Bratash, L.; Zaremba, V.; Havela, L.; Kalychak, Ya.

    2011-10-15

    Isothermal section of the Er-Ni-In system at T=870 K was constructed by means of X-ray powder diffraction and EDX-analyses. Nine ternary compounds, namely ErNi{sub 9}In{sub 2} (YNi{sub 9}In{sub 2}-type), Er{sub 1-1.22}Ni{sub 4}In{sub 1-0.78} (MgCu{sub 4}Sn-type), Er{sub 10}Ni{sub 9.07}In{sub 20} (Ho{sub 10}Ni{sub 9}In{sub 20}-type), ErNi{sub 1-0.60}In{sub 1-1.40} (ZrNiAl-type), Er{sub 2}Ni{sub 2}In (Mn{sub 2}AlB{sub 2}-type), Er{sub 2}Ni{sub 1.78}In (Mo{sub 2}FeB{sub 2}-type), Er{sub 5}Ni{sub 2}In{sub 4} (Lu{sub 5}Ni{sub 2}In{sub 4}-type), Er{sub 5}Ni{sub 2}In (Mo{sub 5}SiB{sub 2}-type), and Er{sub 13.53}Ni{sub 3.14}In{sub 3.33} (Lu{sub 14}Co{sub 2}In{sub 3}-type), exist in the Er-Ni-In system at this temperature. The substitution of Ni for In was observed for ErNi{sub 1-0.60}In{sub 1-1.40} and In for Er in the case of related compounds ErNi{sub 2} and ErNi{sub 4}In. Er can enter NiIn (CoSn-type) leading to including-substitution type of compound Er{sub 0-0.12}NiIn{sub 1-0.89}. Basic magnetic properties of the Er{sub 0.04}NiIn{sub 0.97}, ErNi{sub 2}, Er{sub 0.9}Ni{sub 2}In{sub 0.1}, and ErNi{sub 4}In phases were inspected. Electrical-resistivity studies were performed on the ErNiIn, ErNi{sub 0.9}In{sub 1.1}, and ErNi{sub 4}In phases. - Graphical Abstract: Phase relations in the ternary system Er-Ni-In have been established for the isothermal section at T=870 K based on X-ray phase and EDX-analyses. Nine ternary compounds were observed. Highlights: > Isothermal section of Er-Ni-In system at T=870 K was constructed. > Nine ternary compounds were detected. > Basic magnetic properties of Er{sub 0.04}NiIn{sub 0.97} and ErNi{sub 4}In phases were inspected.

  14. HSP72 protects cells from ER stress-induced apoptosis via enhancement of IRE1alpha-XBP1 signaling through a physical interaction.

    PubMed

    Gupta, Sanjeev; Deepti, Ayswaria; Deegan, Shane; Lisbona, Fernanda; Hetz, Claudio; Samali, Afshin

    2010-07-06

    Endoplasmic reticulum (ER) stress is a feature of secretory cells and of many diseases including cancer, neurodegeneration, and diabetes. Adaptation to ER stress depends on the activation of a signal transduction pathway known as the unfolded protein response (UPR). Enhanced expression of Hsp72 has been shown to reduce tissue injury in response to stress stimuli and improve cell survival in experimental models of stroke, sepsis, renal failure, and myocardial ischemia. Hsp72 inhibits several features of the intrinsic apoptotic pathway. However, the molecular mechanisms by which Hsp72 expression inhibits ER stress-induced apoptosis are not clearly understood. Here we show that Hsp72 enhances cell survival under ER stress conditions. The UPR signals through the sensor IRE1alpha, which controls the splicing of the mRNA encoding the transcription factor XBP1. We show that Hsp72 enhances XBP1 mRNA splicing and expression of its target genes, associated with attenuated apoptosis under ER stress conditions. Inhibition of XBP1 mRNA splicing either by dominant negative IRE1alpha or by knocking down XBP1 specifically abrogated the inhibition of ER stress-induced apoptosis by Hsp72. Regulation of the UPR was associated with the formation of a stable protein complex between Hsp72 and the cytosolic domain of IRE1alpha. Finally, Hsp72 enhanced the RNase activity of recombinant IRE1alpha in vitro, suggesting a direct regulation. Our data show that binding of Hsp72 to IRE1alpha enhances IRE1alpha/XBP1 signaling at the ER and inhibits ER stress-induced apoptosis. These results provide a physical connection between cytosolic chaperones and the ER stress response.

  15. ER Adaptor SCAP Translocates and Recruits IRF3 to Perinuclear Microsome Induced by Cytosolic Microbial DNAs

    PubMed Central

    Yu, Huansha; Liu, Xing; Huang, Lulu; Wang, Qiang; Liu, Heng; Cui, Ye; Tang, Yijun; Zhang, Peng; Wang, Chen

    2016-01-01

    Stimulator of interferon genes (STING, also known as MITA, ERIS or MPYS) induces the activation of TBK1 kinase and IRF3 transcription factor, upon sensing of microbial DNAs. How IRF3 is recruited onto the STING signalosome remains unknown. We report here that silencing of the ER adaptor SCAP markedly impairs the IRF3-responsive gene expression induced by STING. Scap knockdown mice are more susceptible to HSV-1 infection. Interestingly, SCAP translocates from ER, via Golgi, to perinuclear microsome in a STING-dependent manner. Mechanistically, the N-terminal transmembrane domain of SCAP interacts with STING, and the C-terminal cytosolic domain of SCAP binds to IRF3, thus recruiting IRF3 onto STING signalosome. Mis-localization of SCAP abolishes its antiviral function. Collectively, this study characterizes SCAP as an essential adaptor in the STING signaling pathway, uncovering a critical missing link in DNAs-triggered host antiviral responses. PMID:26900919

  16. Lindane may modulate the female reproductive development through the interaction with ER-beta: an in vivo-in vitro approach.

    PubMed

    Maranghi, Francesca; Rescia, Michele; Macrì, Caterina; Di Consiglio, Emma; De Angelis, Giovanna; Testai, Emanuela; Farini, Donatella; De Felici, Massimo; Lorenzetti, Stefano; Mantovani, Alberto

    2007-08-15

    Lindane (gamma-HCH) is a persistent environmental pollutant that may act as endocrine disrupter, affecting the nervous, immune and reproductive system, possibly through endocrine-mediated mechanisms. Since both estrogen receptors (ER-alpha and -beta) have shown to be target for endocrine disruption, we investigated the role of gamma-HCH on the development of female reproductive system. For an in vivo evaluation of gamma-HCH effects during prenatal period, pregnant CD1 mice were treated p.o. on gestational days 9-16 with 15 mg/kg bw/day of gamma-HCH and vehicle. The in vivo findings in treated F1 pups - in the absence of signs of systemic toxicity - included increase in the absolute and relative and absolute uterus weight revealed on post-natal day 22, earlier vaginal patency and reduced diameters of primary oocytes at fully sexual maturity. No effects on steroid hormone metabolism (aromatase, testosterone catabolism) were observed. Thus, gamma-HCH elicited subtle effects on female reproductive development likely mediated by ER-beta-mediated pathway(s), without a concurrent impairment of steroid hormone metabolism. Furthermore, to verify whether the endocrine interference of gamma-HCH is attributable to stimulation of ER-beta-mediated pathway(s), its effect has been evaluated in vitro on a cell line, LNCaP, expressing only functional ER-beta. In vitro treatments revealed a concentration-related effect on LNCaP cell viability and proliferation. Significantly, the contemporary addition of a pure anti-estrogen, the ER antagonist ICI 182,780, completely reversed gamma-HCH effects indicating an ER-beta-mediated action. Our findings indicate that gamma-HCH may act as endocrine disruptor during the female reproductive system development and ER-beta as a potential target for this compound and other endocrine disrupting chemicals as well.

  17. Relationship between RUNX1 and AXIN1 in ER-negative versus ER-positive Breast Cancer.

    PubMed

    Chimge, Nyam-Osor; Ahmed-Alnassar, Sara; Frenkel, Baruch

    2017-02-16

    RUNX1 plays opposing roles in breast cancer: a tumor suppressor in estrogen receptor-positive (ER(+)) disease and an oncogenic role in ER-negative (ER(-)) tumors. Potentially mediating the former, we have recently reported that RUNX1 prevents estrogen-driven suppression of the mRNA encoding the tumor suppressor AXIN1. Accordingly, AXIN1 protein expression was diminished upon RUNX1 silencing in ER(+) breast cancer cells and was positively correlated with AXIN1 protein expression across tumors with high levels of ER. Here we report the surprising observation that RUNX1 and AXIN1 proteins are strongly correlated in ER(-) tumors as well. However, this correlation is not attributable to regulation of AXIN1 by RUNX1 or vice versa. The unexpected correlation between RUNX1, playing an oncogenic role in ER(-) breast cancer, and AXIN1, a well-established tumor suppressor hub, may be related to a high ratio between the expression of variant 2 and variant 1 (v2/v1) of AXIN1 in ER(-) compared with ER(+) breast cancer. Although both isoforms are similarly regulated by RUNX1 in estrogen-stimulated ER(+) breast cancer cells, the higher v2/v1 ratio in ER(-) disease is expected to weaken the tumor suppressor activity of AXIN1 in these tumors.

  18. Penta-EF-Hand Protein Peflin Is a Negative Regulator of ER-To-Golgi Transport

    PubMed Central

    Held, Aaron; Sargeant, John; Thorsen, Kevin; Hay, Jesse C.

    2016-01-01

    Luminal calcium regulates vesicle transport early in the secretory pathway. In ER-to-Golgi transport, depletion of luminal calcium leads to significantly reduced transport and a buildup of budding and newly budded COPII vesicles and vesicle proteins. Effects of luminal calcium on transport may be mediated by cytoplasmic calcium sensors near ER exits sites (ERES). The penta-EF-hand (PEF) protein apoptosis-linked gene 2 (ALG-2) stabilizes sec31A at ER exit sites (ERES) and promotes the assembly of inner and outer shell COPII components. However, in vitro and intact cell approaches have not determined whether ALG-2 is a negative or positive regulator, or a regulator at all, under basal physiological conditions. ALG-2 interacts with another PEF protein, peflin, to form cytosolic heterodimers that dissociate in response to calcium. However, a biological function for peflin has not been demonstrated and whether peflin and the ALG-2/peflin interaction modulates transport has not been investigated. Using an intact, single cell, morphological assay for ER-to-Golgi transport in normal rat kidney (NRK) cells, we found that depletion of peflin using siRNA resulted in significantly faster transport of the membrane cargo VSV-G. Double depletion of peflin and ALG-2 blocked the increased transport resulting from peflin depletion, demonstrating a role for ALG-2 in the increased transport. Furthermore, peflin depletion caused increased targeting of ALG-2 to ERES and increased ALG-2/sec31A interactions, suggesting that peflin may normally inhibit transport by preventing ALG-2/sec31A interactions. This work identifies for the first time a clear steady state role for a PEF protein in ER-to-Golgi transport—peflin is a negative regulator of transport. PMID:27276012

  19. Tamoxifen inhibits ER-negative breast cancer cell invasion and metastasis by accelerating Twist1 degradation.

    PubMed

    Ma, Gang; He, Jianjun; Yu, Yang; Xu, Yixiang; Yu, Xiaobin; Martinez, Jarrod; Lonard, David M; Xu, Jianming

    2015-01-01

    Twist1 is a transcription factor driving epithelial-mesenchymal transition, invasion and metastasis of breast cancer cells. Mice with germ-line Twist1 knockout are embryonic lethal, while adult mice with inducible Twist1 knockout have no obvious health problems, suggesting that Twist1 is a viable therapeutic target for the inhibition of invasion and metastasis of breast cancer in adult patients. In this study, we expressed a luciferase protein or a Twist1-luciferase fusion protein in HeLa cells as part of a high throughput system to screen 1280 compounds in the Library of Pharmacologically Active Compounds (LOPAC) from Sigma-Aldrich for their effects on Twist1 protein expression. One of the most interesting compounds identified is tamoxifen, a selective estrogen receptor (ER) modulator used to treat ER-positive breast cancer. Tamoxifen treatment significantly accelerated Twist1 degradation in multiple cell lines including HEK293 human kidney cells, 4T1 and 168FARN mouse mammary tumor cells with either ectopically or endogenously expressed Twist1. Tamoxifen-induced Twist1 degradation could be blocked by the MG132 proteasome inhibitor, suggesting that tamoxifen induces Twist1 degradation through the ubiquitination-proteasome pathway. However, tamoxifen-induced Twist1 degradation was independent of Twist1 mRNA expression, estrogen signaling and MAPK-mediated Twist1 phosphorylation in these cells. Importantly, tamoxifen also significantly inhibited invasive behavior in Matrigel and lung metastasis in SCID-bg mice of ER-negative 4T1 mammary tumor cells, which depend on endogenous Twist1 to invade and metastasize. These results indicate that tamoxifen can significantly accelerate Twist1 degradation to suppress cancer cell invasion and metastasis, suggesting that tamoxifen can be used not only to treat ER-positive breast cancers but also to reduce Twist1-mediated invasion and metastasis in ER-negative breast cancers.

  20. Multiple GTP-binding proteins regulate vesicular transport from the ER to Golgi membranes

    PubMed Central

    1992-01-01

    Using indirect immunofluorescence we have examined the effects of reagents which inhibit the function of ras-related rab small GTP- binding proteins and heterotrimeric G alpha beta gamma proteins in ER to Golgi transport. Export from the ER was inhibited by an antibody towards rab1B and an NH2-terminal peptide which inhibits ARF function (Balch, W. E., R. A. Kahn, and R. Schwaninger. 1992. J. Biol. Chem. 267:13053-13061), suggesting that both of these small GTP-binding proteins are essential for the transport vesicle formation. Export from the ER was also potently inhibited by mastoparan, a peptide which mimics G protein binding regions of seven transmembrane spanning receptors activating and uncoupling heterotrimeric G proteins from their cognate receptors. Consistent with this result, purified beta gamma subunits inhibited the export of VSV-G from the ER suggesting an initial event in transport vesicle assembly was regulated by a heterotrimeric G protein. In contrast, incubation in the presence of GTP gamma S or AIF(3-5) resulted in the accumulation of transported protein in different populations of punctate pre-Golgi intermediates distributed throughout the cytoplasm of the cell. Finally, a peptide which is believed to antagonize the interaction of rab proteins with putative downstream effector molecules inhibited transport at a later step preceding delivery to the cis Golgi compartment, similar to the site of accumulation of transported protein in the absence of NSF or calcium (Plutner, H., H. W. Davidson, J. Saraste, and W. E. Balch. 1992. J. Cell Biol. 119:1097-1116). These results are consistent with the hypothesis that multiple GTP-binding proteins including a heterotrimeric G protein(s), ARF and rab1 differentially regulate steps in the transport of protein between early compartments of the secretory pathway. The concept that G protein-coupled receptors gate the export of protein from the ER is discussed. PMID:1447289

  1. Effects of Ergosterol on COPD in Mice via JAK3/STAT3/NF-κB Pathway.

    PubMed

    Huan, Wang; Tianzhu, Zhang; Yu, Li; Shumin, Wang

    2017-03-01

    The present study was to evaluate the effect of ergosterol (ER) on CS (cigarette smoke)-induced chronic obstructive pulmonary disease (COPD) in mice. Fifty male ICR mice were randomly assigned to five groups: control group, CS group, CS + dexamethasone (Dex, 2 mg/kg) group, CS + ER (ER, 25 mg/kg) group, CS + ER (ER, 50 mg/kg). H&E staining demonstrated that ER inhibited CS-induced pathological injury in lung tissue. Besides, ER could restore the activities of superoxide dismutase (SOD) in serum and in the lung, catalase (CAT) in serum and reduce the content of malondialdehyde (MDA) in serum and in the lung. ER also inhibited pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) in serum and the lung. Furthermore, ER significantly inhibited the protein expression of JAK3/STAT3/NF-κB pathway in CS-induced mice. Our findings suggested that ER might effectively ameliorate the progression of COPD via JAK3/STAT3/NF-κB pathway in mice.

  2. On the Use of an ER-213 Detonator to Establish a Baseline for the ER-486

    SciTech Connect

    Thomas, Keith A.; Liechty, Gary H.; Jaramillo, Dennis C.; Munger, Alan C.; McHugh, Douglas C.; Kennedy, James E.

    2014-08-19

    This report documents a series of tests using a TSD-115 fireset coupled with an ER-213, a gold exploding bridgewire (EBW) detonator. These tests were designed to fire this EBW with a smaller fireset to obtain current and voltage data as well as timing information at voltage levels below, above, and throughout the threshold firing region. This study could then create a database for comparison to our current ER-486 EBW development, which is designed to be a lower voltage (<500V) device.

  3. Global Assessment of Reprocessed ERS-1 and ERS-2 Altimetry (REAPER) Wind and Wave Products

    NASA Astrophysics Data System (ADS)

    Abdalla, Saleh; Bidlot, Jean-Raymond; Janssen, Peter A. E. M.

    2016-08-01

    ESA has been committed to reprocess its Earth Observation Missions of ERS and ENVISAT to produce long and homogeneous time series suitable for climate studies. The full-mission reprocessing of the ERS Altimetry Level 2 REAPER was completed sometime ago. The REAPER wind and wave products are assessed mainly against ERA-Interim which is a rather consistent model run. Several numerical experiments were carried out in order to assess the impact of assimilating the reprocessed significant wave height data in the ECMWF wave model for potential use in the most recent ECMWF atmospheric reanalysis ERA-5. The results show positive impact.

  4. Bulk Er:YAP and Er:Yb:YAP optical emission studies for eyesafe laser applications

    NASA Astrophysics Data System (ADS)

    Georgiou, Efstratios; Boquillon, Jean-Pierre; Musset, Olivier

    2012-06-01

    Emission and excitation spectra of Er-doped YAP crystals reveal a broad emission band in the eyesafe region with peaks around 1545-nm and 1608-nm and pump-bands suitable for common 800-nm and 970-nm diode lasers, suggesting YAP as a candidate crystalline host for diode-pumped laser in the 1.5-μm eyesafe regime. Erbium-doped YAP-crystal results are comparable with analogous measurements on Er:Yb:YAG, which has already demostrated efficient lasing action in the eyesafe region.

  5. Estrogen Signaling Multiple Pathways to Impact Gene Transcription

    PubMed Central

    Marino, Maria; Galluzzo, Paola; Ascenzi, Paolo

    2006-01-01

    Steroid hormones exert profound effects on cell growth, development, differentiation, and homeostasis. Their effects are mediated through specific intracellular steroid receptors that act via multiple mechanisms. Among others, the action mechanism starting upon 17β-estradiol (E2) binds to its receptors (ER) is considered a paradigmatic example of how steroid hormones function. Ligand-activated ER dimerizes and translocates in the nucleus where it recognizes specific hormone response elements located in or near promoter DNA regions of target genes. Behind the classical genomic mechanism shared with other steroid hormones, E2 also modulates gene expression by a second indirect mechanism that involves the interaction of ER with other transcription factors which, in turn, bind their cognate DNA elements. In this case, ER modulates the activities of transcription factors such as the activator protein (AP)-1, nuclear factor-κB (NF-κB) and stimulating protein-1 (Sp-1), by stabilizing DNA-protein complexes and/or recruiting co-activators. In addition, E2 binding to ER may also exert rapid actions that start with the activation of a variety of signal transduction pathways (e.g. ERK/MAPK, p38/MAPK, PI3K/AKT, PLC/PKC). The debate about the contribution of different ER-mediated signaling pathways to coordinate the expression of specific sets of genes is still open. This review will focus on the recent knowledge about the mechanism by which ERs regulate the expression of target genes and the emerging field of integration of membrane and nuclear receptor signaling, giving examples of the ways by which the genomic and non-genomic actions of ERs on target genes converge. PMID:18369406

  6. Recombinant Newcastle disease virus (rL-RVG) triggers autophagy and apoptosis in gastric carcinoma cells by inducing ER stress

    PubMed Central

    Bu, Xuefeng; Zhao, Yinghai; Zhang, Zhijian; Wang, Mubin; Li, Mi; Yan, Yulan

    2016-01-01

    We have reported that the recombinant avirulent Newcastle disease virus (NDV) LaSota strain expressing the rabies virus glycoprotein (rL-RVG) could induce autophagy and apoptosis in gastric carcinoma cells. In the present study, we explored the upstream regulators, endoplasmic reticulum (ER) stress that induce autophagy and apoptosis and the relationships among them. For this purpose, SGC-7901 and HGC cells were infected with rL-RVG. NDV LaSota strain and phosphate-buffered saline (PBS) were treated as the control groups. Western blotting and immunofluorescence microscopy were used to detect the expression of the ER stress-related proteins glucose-regulated protein 78 (GRP78) and the transcription factor GADD153 (CHOP), among others. The expression of beclin-1 and the conversion of light chain (LC) 3-I were used to determine the occurrence of autophagy, and flow cytometry (FCM) and western blotting were used to examine apoptosis-related protein expression. Transmission electron microscopy was also performed to monitor the ultrastructure of the cells. Moreover, small interfering (si) RNA was used to knock down CHOP expression. rL-RVG treatment increased the expression of ER stress-related proteins, such as GRP78, CHOP, activating transcriptional factor 6 (ATF6), X-box-binding protein 1 (XBP-1), and phosphorylated eukaryotic initiation factor 2 (p-eIF2α), in a time- and concentration-dependent manner, and knockdown of CHOP reduced LC3-II conversion and beclin-1 expression. When ER stress was inhibited with 4-PBA, the expression of both autophagy-related proteins and apoptosis-related proteins markedly decreased. Interestingly, inhibition of autophagy with 3-methyladenine (3MA) decreased not only apoptosis-related protein expression but also ER stress-related protein expression. Moreover, we found that downregulation of the c-Jun N-terminal kinase (JNK) pathway by SP600125 reduced LC3-II conversion, beclin-1 expression and caspase-3 activation. Collectively, the

  7. A Novel Carboxyl-Terminal Heptapeptide Initiates the Regulated Secretion of LH from Unique Sub-Domains of the ER

    PubMed Central

    Jablonka-Shariff, Albina; Boime, Irving

    2013-01-01

    The coordinated secretion of LH and FSH are critical for reproductive functions. After translocation into the endoplasmic reticulum (ER), their biosynthetic routes diverge at a determinative step prior to sorting in the regulated (LH) and constitutive (FSH) secretion pathways. Recently, we identified a C-terminal heptapeptide sequence, present only in the LHβ subunit, as a critical signal for entry of the LH dimer into the regulated pathway. We showed that an LHβ mutant lacking the heptapeptide (LHβΔT) assembled more efficiently with the α subunit than wild-type LHβ subunit, and this LHΔT dimer was secreted constitutively. Thus, an association exists between the presence of the C-terminal heptapeptide and sorting of the LH heterodimer to the regulated pathway. To study how this delayed LHβ subunit assembly is related to the trafficking of LH, we exploited the single subunit transfection model in rat somatotrope-derived GH3 cells with the use of immunofluorescence confocal microscopy. The LHβ subunit showed a distinct immunofluorescent localization as compared to the FSHβ subunit and LHβ mutants. The wild-type LHβ subunit exhibited a perinuclear staining corresponding to the ER/nuclear envelope region. In contrast, the wild-type FSHβ subunit and the mutants LHβΔT and LHβL119A displayed no detectable perinuclear staining; only peripheral ER puncta were observed. Also, no perinuclear fluorescence was detected in cells expressing the LH heterodimer. We propose that the C-terminal heptapeptide is responsible for delayed heterodimer assembly within an ER sub-domain of the nuclear envelope, as an early partitioning event necessary for the entrance of LH into the regulated secretory pathway, whereas FSHβ does not traverse the nuclear envelope region. These data suggest that, at least for LH, the molecular decision to enter the regulated secretory pathway is a pre-Golgi event controlled by the novel C-terminal heptapeptide. PMID:23734233

  8. BOREAS Level-0 ER-2 Navigation Data

    NASA Technical Reports Server (NTRS)

    Strub, Richard; Dominguez, Roseanne; Newcomer, Jeffrey A.; Hall, Forrest G. (Editor)

    2000-01-01

    The BOREAS Staff Science effort covered those activities that were BOREAS community-level activities or required uniform data collection procedures across sites and time. These activities included the acquisition, processing, and archiving of aircraft navigation/attitude data to complement the digital image data. The level-0 ER-2 navigation data files contain aircraft attitude and position information acquired during the digital image and photographic data collection missions. Temporally, the data were acquired from April to September 1994. Data were recorded at intervals of 5 seconds. The data are stored in tabular ASCII files.

  9. Atomic transition probabilities of Er i

    NASA Astrophysics Data System (ADS)

    Lawler, J. E.; Wyart, J.-F.; Den Hartog, E. A.

    2010-12-01

    Atomic transition probabilities for 562 lines of the first spectrum of erbium (Er i) are reported. These data are from new branching fraction measurements on Fourier transform spectra normalized with previously reported radiative lifetimes from time-resolved laser-induced fluorescence measurements (Den Hartog et al 2010 J. Phys. B: At. Mol. Opt. Phys. 43 155004). The wavelength range of the data set is from 298 to 1981 nm. In this work we explore the utility of parametric fits based on the Cowan code in assessing branching fraction errors due to lines connecting to unobserved lower levels.

  10. Obesity and endoplasmic reticulum (ER) stresses

    PubMed Central

    Tripathi, Yamini B.; Pandey, Vivek

    2012-01-01

    In obesity, the adipose cells behave as inflammatory source and result to low grade inflammation. This systemic inflammation along with oxidative stress is a silent killer and damages other vital organs also. High metabolic process, induced due to high nutritional intake, results to endoplasmic reticulum (ER) stress and mitochondrial stress. This review describes the triggering factor and basic mechanism behind the obesity mediated these stresses in relation to inflammation. Efforts have been made to describe the effect-response cycle between adipocytes and non-adipocyte cells with reference to metabolic syndrome (MS). PMID:22891067

  11. Caffeine attenuated ER stress-induced leptin resistance in neurons.

    PubMed

    Hosoi, Toru; Toyoda, Keisuke; Nakatsu, Kanako; Ozawa, Koichiro

    2014-05-21

    Exposing the endoplasmic reticulum (ER) to stress causes the accumulation of unfolded proteins, and subsequently results in ER stress. ER stress may be involved in various disorders such as obesity, diabetes, and neurodegenerative diseases. Leptin is an important circulating hormone, that inhibits food intake and accelerates energy consumption, which suppresses body weight gain. Recent studies demonstrated that leptin resistance is one of the main factors involved in the development of obesity. We and other groups recently reported the role of ER stress in the development of leptin resistance. Therefore, identifying drugs that target ER stress may be a promising fundamental strategy for the treatment of obesity. In the present study, we investigated whether caffeine could affect ER stress and the subsequent development of leptin resistance. We showed that caffeine exhibited chaperone activity, which attenuated protein aggregation. Caffeine also inhibited the ER stress-induced activation of IRE1 and PERK, which suggested the attenuation of ER stress. Moreover, caffeine markedly improved ER stress-induced impairments in the leptin-induced phosphorylation of STAT3. Therefore, these results suggest caffeine may have pharmacological properties that ameliorate leptin resistance by reducing ER stress.

  12. Quercetin induces protective autophagy and apoptosis through ER stress via the p-STAT3/Bcl-2 axis in ovarian cancer.

    PubMed

    Liu, Y; Gong, W; Yang, Z Y; Zhou, X S; Gong, C; Zhang, T R; Wei, X; Ma, D; Ye, F; Gao, Q L

    2017-04-01

    Quercetin (3,3',4',5,7-pentahydroxyflavone, Qu) is a promising cancer chemo-preventive agent for various cancers because it inhibits disease progression and promotes apoptotic cell death. In our previous study, we demonstrated that Qu could evoke ER stress to enhance drug cytotoxicity in ovarian cancer (OC). However, Qu-induced ER stress in OC is still poorly understood. Here, we demonstrated that Qu evoked ER stress to involve in mitochondria apoptosis pathway via the p-STAT3/Bcl-2 axis in OC cell lines and in primary OC cells. Unexpectedly, inhibition of ER stress did not reverse Qu-induced cell death. Further functional studies revealed that Qu-induced ER stress could activate protective autophagy concomitantly by activating the p-STAT3/Bcl-2 axis in this process. Moreover, the autophagy scavenger 3-MA was shown to enhance Qu's anticancer effects in an ovarian cancer mice xenograft model. These findings revealed a novel role of ER stress as a "double edge sword" participating in Qu-induced apoptosis of OC and might provide a new angle to consider in clinical studies of biological modifiers that may circumvent drug resistance in patients by targeting protective autophagy pathways.

  13. Bcl2 at the endoplasmic reticulum protects against a Bax/Bak-independent paraptosis-like cell death pathway initiated via p20Bap31.

    PubMed

    Heath-Engel, Hannah M; Wang, Bing; Shore, Gordon C

    2012-02-01

    Bap31 is an integral ER membrane protein which functions as an escort factor in the sorting of newly synthesized membrane proteins within the endoplasmic reticulum (ER). During apoptosis signaling, Bap31 is subject to early cleavage by initiator caspase-8. The resulting p20Bap31 (p20) fragment has been shown to initiate proapoptotic ER-mitochondria Ca2+ transmission, and to exert dominant negative (DN) effects on ER protein trafficking. We now report that ectopic expression of p20 in E1A/DNp53-transformed baby mouse kidney epithelial cells initiates a non-apoptotic form of cell death with paraptosis-like morphology. This pathway was characterized by an early rise in ER Ca2+ stores and massive dilation of the ER/nuclear envelope, dependent on intact ER Ca2+ stores. Ablation of the Bax/Bak genes had no effect on these ER/nuclear envelope transformations, and delayed but did not prevent cell death. ER-restricted expression of Bcl2 in the absence of Bax/Bak, however, delayed both ER/nuclear envelope dilation and cell death. This prosurvival role of Bcl2 at the ER thus extended beyond inhibition of Bax/Bak, and correlated with its ability to lower ER Ca2+ stores. Furthermore, these results indicate that ER restricted Bcl2 is capable of antagonizing not only apoptosis, but also a non-apoptotic, Bax/Bak independent, paraptosis-like form of cell death.

  14. Rab1-dependent ER-Golgi transport dysfunction is a common pathogenic mechanism in SOD1, TDP-43 and FUS-associated ALS.

    PubMed

    Soo, Kai Y; Halloran, Mark; Sundaramoorthy, Vinod; Parakh, Sonam; Toth, Reka P; Southam, Katherine A; McLean, Catriona A; Lock, Peter; King, Anna; Farg, Manal A; Atkin, Julie D

    2015-11-01

    Several diverse proteins are linked genetically/pathologically to neurodegeneration in amyotrophic lateral sclerosis (ALS) including SOD1, TDP-43 and FUS. Using a variety of cellular and biochemical techniques, we demonstrate that ALS-associated mutant TDP-43, FUS and SOD1 inhibit protein transport between the endoplasmic reticulum (ER) and Golgi apparatus in neuronal cells. ER-Golgi transport was also inhibited in embryonic cortical and motor neurons obtained from a widely used animal model (SOD1(G93A) mice), validating this mechanism as an early event in disease. Each protein inhibited transport by distinct mechanisms, but each process was dependent on Rab1. Mutant TDP-43 and mutant FUS both inhibited the incorporation of secretory protein cargo into COPII vesicles as they bud from the ER, and inhibited transport from ER to the ER-Golgi intermediate (ERGIC) compartment. TDP-43 was detected on the cytoplasmic face of the ER membrane, whereas FUS was present within the ER, suggesting that transport is inhibited from the cytoplasm by mutant TDP-43, and from the ER by mutant FUS. In contrast, mutant SOD1 destabilised microtubules and inhibited transport from the ERGIC compartment to Golgi, but not from ER to ERGIC. Rab1 performs multiple roles in ER-Golgi transport, and over-expression of Rab1 restored ER-Golgi transport, and prevented ER stress, mSOD1 inclusion formation and induction of apoptosis, in cells expressing mutant TDP-43, FUS or SOD1. Rab1 also co-localised extensively with mutant TDP-43, FUS and SOD1 in neuronal cells, and Rab1 formed inclusions in motor neurons of spinal cords from sporadic ALS patients, which were positive for ubiquitinated TDP-43, implying that Rab1 is misfolded and dysfunctional in sporadic disease. These results demonstrate that ALS-mutant forms of TDP-43, FUS, and SOD1 all perturb protein transport in the early secretory pathway, between ER and Golgi compartments. These data also imply that restoring Rab1-mediated ER

  15. A conserved, lipid-mediated sorting mechanism of yeast Ist2 and mammalian STIM proteins to the peripheral ER.

    PubMed

    Ercan, Ebru; Momburg, Frank; Engel, Ulrike; Temmerman, Koen; Nickel, Walter; Seedorf, Matthias

    2009-12-01

    Sorting of yeast Ist2 to the plasma membrane (PM) or the cortical endoplasmic reticulum (ER) requires a cortical sorting signal (CSS(Ist2)) that interacts with lipids including phosphatidylinositol-4,5-bisphosphate (PI(4,5)P(2)) at the PM. Here, we show that the expression of Ist2 in mammalian cells resulted in a peripheral patch-like localization without any detection of Ist2 at the cell surface. Attached to C-termini of mammalian integral membrane proteins, the CSS(Ist2) targeted these proteins to PM-associated domains of the ER and abolished trafficking via the classical secretory pathway. The interaction of integral membrane proteins with PI(4,5)P(2) at the PM created ER-PM contacts. This process is similar to the regulated coupling of ER domains to the PM via stromal interaction molecule (STIM) proteins during store-operated Ca(2+) entry (SOCE). The CSS(Ist2) and the C-terminus of the ER-located Ca(2+) sensor STIM2 were sufficient to bind PI(4,5)P(2) and PI(3,4,5)P(3) at the PM, showing that an evolutionarily conserved mechanism is involved in the sorting of integral membrane proteins to PM-associated domains of the ER. Yeast Ist2 and STIM2 share a common basic and amphipathic signal at their extreme C-termini. STIM1 showed binding preference for liposomes containing PI(4,5)P(2), suggesting a specific contribution of lipids to the recruitment of ER domains to the PM during SOCE.

  16. Infrared radiometry of dental enamel during Er:YAG and Er:YSGG laser irradiation

    NASA Astrophysics Data System (ADS)

    Fried, Daniel; Visuri, Steven R.; Featherstone, John D.; Walsh, Joseph T.; Seka, Wolf D.; Glena, Richard E.; McCormack, Sandra M.; Wigdor, Harvey A.

    1996-10-01

    Time-resolved infrared radiometry was used to measure surface temperatures during pulsed Er:YSGG and Er:YAG laser irradiation of dental enamel. Scanning electron microscopy (SEM) was used to determine the melting and vaporization thresholds and to characterize other changes in the surface morphology. The magnitude and temporal evolution of the surface temperature during multiple-pulse irradiation of the tissue was dependant on the wavelength, fluence, and pre- exposure to laser pulses. Radiometry and SEM micrographs indicate that ablation is initiated at temperatures well below the melting and vaporization temperatures of the carbonated hydroxyapatite mineral component. Ablation occurred at lower surface temperatures and at a lower fluences for Er:YAG than for Er:YSGG laser irradiation: 400 degrees C versus 800 degrees C and above 7 J/cm2 versus 18/Jcm2, respectively. However, the measured surface temperatures were higher at (lambda) equals 2.79 (Mu) m than at (lambda) equals 2.94 during low fluence irradiation. Spatially dependent absorption in the enamel matrix is proposed to explain this apparent contradiction.

  17. ER/PR Status of the Originating Cell of ER-Negative Breast Cancer

    DTIC Science & Technology

    2009-04-01

    levels. Therefore, the best ER BAC clon available at this time cannot express an However, while we were in the process of starting to make TVA...knock-in, we found the following surprise result that provides an alternati We have also created a transgenic line expressing tva from the whey acidic

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

    PubMed Central

    Gomez, Javier A; Rutkowski, D Thomas

    2016-01-01

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

  19. Role of Sec61p in the ER-associated degradation of short-lived transmembrane proteins

    PubMed Central

    Scott, Daniel C.; Schekman, Randy

    2008-01-01

    Misfolded proteins in the endoplasmic reticulum (ER) are identified and degraded by the ER-associated degradation pathway (ERAD), a component of ER quality control. In ERAD, misfolded proteins are removed from the ER by retrotranslocation into the cytosol where they are degraded by the ubiquitin–proteasome system. The identity of the specific protein components responsible for retrotranslocation remains controversial, with the potential candidates being Sec61p, Der1p, and Doa10. We show that the cytoplasmic N-terminal domain of a short-lived transmembrane ERAD substrate is exposed to the lumen of the ER during the degradation process. The addition of N-linked glycan to the N terminus of the substrate is prevented by mutation of a specific cysteine residue of Sec61p, as well as a specific cysteine residue of the substrate protein. We show that the substrate protein forms a disulfide-linked complex to Sec61p, suggesting that at least part of the retrotranslocation process involves Sec61p. PMID:18573918

  20. Crystal Lattice Defects in MBE Grown Si Layers Heavily Doped with Er

    NASA Astrophysics Data System (ADS)

    Zakharov, N. D.; Werner, P.; Vdovin, V. I.; Denisov, D. V.; Sobolev, N. A.; Gösele, U.

    The main types of crystal structure defects in [Er]>2×1019 doped layers are: (i) spherical Er and (ii) ellipsoidal ErSi precipitates, as well as (iii) ErSi2 platelets on {111} planes. In the sample with [Er]=4x1019, small complexes consisting of tiny Er precipitates and four petals of ErSi2 platelets have been found additionally. The layer with [Er]= 8×1018 cm-3 was defect free. The formation of silicides from a supersaturated solid solution and Er precipitates is accompanied by the emission of vacancies V resulting in the formation of pores, V-V and V-Er complexes.

  1. Dysfunction of Wntless triggers the retrograde Golgi-to-ER transport of Wingless and induces ER stress.

    PubMed

    Zhang, Peng; Zhou, Lujun; Pei, Chunli; Lin, Xinhua; Yuan, Zengqiang

    2016-02-18

    Secreted Wnts play diverse roles in a non-cell-autonomous fashion. However, the cell-autonomous effect of unsecreted Wnts remains unknown. Endoplasmic reticulum (ER) stress is observed in specialized secretory cells and participates in pathophysiological processes. The correlation between Wnt secretion and ER stress remains poorly understood. Here, we demonstrated that Drosophila miR-307a initiates ER stress specifically in wingless (wg)-expressing cells through targeting wntless (wls/evi). This phenotype could be mimicked by retromer loss-of-function or porcupine (porc) depletion, and rescued by wg knockdown, arguing that unsecreted Wg triggers ER stress. Consistently, we found that disrupting the secretion of human Wnt5a also induced ER stress in mammalian cells. Furthermore, we showed that a C-terminal KKVY-motif of Wg is required for its retrograde Golgi-to-ER transport, thus inducing ER stress. Next, we investigated if COPI, the regulator of retrograde transport, is responsible for unsecreted Wg to induce ER stress. To our surprise, we found that COPI acts as a novel regulator of Wg secretion. Taken together, this study reveals a previously unknown Golgi-to-ER retrograde route of Wg, and elucidates a correlation between Wnt secretion and ER stress during development.

  2. Dysfunction of Wntless triggers the retrograde Golgi-to-ER transport of Wingless and induces ER stress

    PubMed Central

    Zhang, Peng; Zhou, Lujun; Pei, Chunli; Lin, Xinhua; Yuan, Zengqiang

    2016-01-01

    Secreted Wnts play diverse roles in a non-cell-autonomous fashion. However, the cell-autonomous effect of unsecreted Wnts remains unknown. Endoplasmic reticulum (ER) stress is observed in specialized secretory cells and participates in pathophysiological processes. The correlation between Wnt secretion and ER stress remains poorly understood. Here, we demonstrated that Drosophila miR-307a initiates ER stress specifically in wingless (wg)-expressing cells through targeting wntless (wls/evi). This phenotype could be mimicked by retromer loss-of-function or porcupine (porc) depletion, and rescued by wg knockdown, arguing that unsecreted Wg triggers ER stress. Consistently, we found that disrupting the secretion of human Wnt5a also induced ER stress in mammalian cells. Furthermore, we showed that a C-terminal KKVY-motif of Wg is required for its retrograde Golgi-to-ER transport, thus inducing ER stress. Next, we investigated if COPI, the regulator of retrograde transport, is responsible for unsecreted Wg to induce ER stress. To our surprise, we found that COPI acts as a novel regulator of Wg secretion. Taken together, this study reveals a previously unknown Golgi-to-ER retrograde route of Wg, and elucidates a correlation between Wnt secretion and ER stress during development. PMID:26887613

  3. Magnetic properties of ErN films

    NASA Astrophysics Data System (ADS)

    Meyer, C.; Ruck, B. J.; Preston, A. R. H.; Granville, S.; Williams, G. V. M.; Trodahl, H. J.

    2010-07-01

    We report a magnetization study of stoichiometric ErN nanocrystalline films grown on Si and protected by a GaN passivating layer. According to the temperature dependence of the resistivity the films are heavily doped semiconductors. Above 100 K the magnetization data fit well to a Curie-Weiss behavior with a moment expected within the free-ion ErJ={15}/{2} multiplet. Below 50 K the Curie-Weiss plot steepens to an effective moment corresponding to that in the crystal-field determined quartet ground state, and develops a clear paramagnetic Curie-Weiss temperature of about 4.5 K. Zero-field- and field-cooled magnetization curves and the AC susceptibility firmly establish a ferromagnetic ground state within that multiplet below a Curie temperature of 6.3±0.7 K. Due to the (1 1 1) texture of the film the comparison between the magnetization behavior, when the field is applied parallel and perpendicular to the film plane, gives new information about the magnetic structure. An arrangement of the moments according to the model derived from neutron diffraction for bulk HoN is strongly suggested.

  4. Binding of plasma membrane lipids recruits the yeast integral membrane protein Ist2 to the cortical ER.

    PubMed

    Fischer, Marcel André; Temmerman, Koen; Ercan, Ebru; Nickel, Walter; Seedorf, Matthias

    2009-08-01

    Recruitment of cytosolic proteins to individual membranes is governed by a combination of protein-protein and protein-membrane interactions. Many proteins recognize phosphatidylinositol 4,5-bisphosphate [PI(4,5)P(2)] at the cytosolic surface of the plasma membrane (PM). Here, we show that a protein-lipid interaction can also serve as a dominant signal for the sorting of integral membrane proteins. Interaction with phosphatidly-inositolphosphates (PIPs) at the PM is involved in the targeting of the polytopic yeast protein Ist2 to PM-associated domains of the cortical endoplasmic reticulum (ER). Moreover, binding of PI(4,5)P(2) at the PM functions as a dominant mechanism that targets other integral membrane proteins to PM-associated domains of the cortical ER. This sorting to a subdomain of the ER abolishes proteasomal degradation and trafficking along the classical secretory (sec) pathway. In combination with the localization of IST2 mRNA to the bud tip and other redundant signals in Ist2, binding of PIPs leads to efficient accumulation of Ist2 at domains of the cortical ER from where the protein may reach the PM independently of the function of the sec-pathway.

  5. Crimean-Congo Hemorrhagic Fever Virus-Infected Hepatocytes Induce ER-Stress and Apoptosis Crosstalk

    PubMed Central

    Rodrigues, Raquel; Paranhos-Baccalà, Gláucia; Vernet, Guy; Peyrefitte, Christophe N.

    2012-01-01

    Crimean-Congo hemorrhagic fever virus (CCHFV) is a widely distributed tick-borne member of the Nairovirus genus (Bunyaviridae) with a high mortality rate in humans. CCHFV induces a severe disease in infected patients that includes, among other symptoms, massive liver necrosis and failure. The interaction between liver cells and CCHFV is therefore important for understanding the pathogenesis of this disease. Here, we described the in vitro CCHFV-infection and -replication in the hepatocyte cell line, Huh7, and the induced cellular and molecular response modulation. We found that CCHFV was able to infect and replicate to high titres and to induce a cytopathic effect (CPE). We also observed by flow cytometry and real time quantitative RT-PCR evidence of apoptosis, with the participation of the mitochondrial pathway. On the other hand, we showed that the replication of CCHFV in hepatocytes was able to interfere with the death receptor pathway of apoptosis. Furthermore, we found in CCHFV-infected cells the over-expression of PUMA, Noxa and CHOP suggesting the crosstalk between the ER-stress and mitochondrial apoptosis. By ELISA, we observed an increase of IL-8 in response to viral replication; however apoptosis was shown to be independent from IL-8 secretion. When we compared the induced cellular response between CCHFV and DUGV, a mild or non-pathogenic Nairovirus for humans, we found that the most striking difference was the absence of CPE and apoptosis. Despite the XBP1 splicing and PERK gene expression induced by DUGV, no ER-stress and apoptosis crosstalk was observed. Overall, these results suggest that CCHFV is able to induce ER-stress, activate inflammatory mediators and modulate both mitochondrial and death receptor pathways of apoptosis in hepatocyte cells, which may, in part, explain the role of the liver in the pathogenesis of CCHFV. PMID:22238639

  6. Fluorescence of Er3+:AlN Polycrystalline Ceramic

    DTIC Science & Technology

    2012-01-01

    using heating techniques and sintering aids such as hot pressing with Ca(NO3)2•4H2O [19], spark plasma sintering with CaF2 [20], and pressureless...Cleveland, OH, U.S.A.) to determine the levels of Er before and after sintering . The starting powders (measured using Inductively Coupled Plasma ...optical spectroscopy of Er3+ doped into bulk AlN ceramic. The material was prepared via hot press sintering of AlN with Er2O3 and [NH4][ErF4], which

  7. Lanthanum Titanate Nanoparticles ER Fluids with High Performance

    NASA Astrophysics Data System (ADS)

    Wang, De; Shen, Rong; Wei, Shiqiang; Lu, Kunquan

    A new type of electrorheological (ER) fluid consisting of lanthanum titanate (LTO) nanoparticles is developed. The ER fluids were prepared by suspending LTO powder in silicone oil and the particles were fabricated by wet chemical method. This ER fluid shows excellent ER properties: The static yield stress reaches over 150 kPa under 5 kV/mm with linear dependence on the applied DC electric field, and the current density is below 10 μA/cm2. In order to investigate the affect factor on the ER behavior, the LTO powder were heated under different temperatures. The ER performances of two particles treated under different temperatures were compared and the composition changes for those particles were analyzed with TG-FTIR technique. It was found that the static yield stress of the suspensions fell from over 150 kPa to about 40 kPa and the current densities decreased prominently as the rise of the heating temperature. TG-FTIR analysis indicated that polar groups remained in the particles such as alkyl group, hydroxyl group and carbonyl group etc., contribute to the ER effect significantly. The experimental results are helpful to understand the mechanism of the high ER effect and to synthesize better ER materials.

  8. Cooperative Dynamics of AR and ER Activity in Breast Cancer.

    PubMed

    D'Amato, Nicholas C; Gordon, Michael A; Babbs, Beatrice; Spoelstra, Nicole S; Carson Butterfield, Kiel T; Torkko, Kathleen C; Phan, Vernon T; Barton, Valerie N; Rogers, Thomas J; Sartorius, Carol A; Elias, Anthony; Gertz, Jason; Jacobsen, Britta M; Richer, Jennifer K

    2016-11-01

    Androgen receptor (AR) is expressed in 90% of estrogen receptor alpha-positive (ER(+)) breast tumors, but its role in tumor growth and progression remains controversial. Use of two anti-androgens that inhibit AR nuclear localization, enzalutamide and MJC13, revealed that AR is required for maximum ER genomic binding. Here, a novel global examination of AR chromatin binding found that estradiol induced AR binding at unique sites compared with dihydrotestosterone (DHT). Estradiol-induced AR-binding sites were enriched for estrogen response elements and had significant overlap with ER-binding sites. Furthermore, AR inhibition reduced baseline and estradiol-mediated proliferation in multiple ER(+)/AR(+) breast cancer cell lines, and synergized with tamoxifen and fulvestrant. In vivo, enzalutamide significantly reduced viability of tamoxifen-resistant MCF7 xenograft tumors and an ER(+)/AR(+) patient-derived model. Enzalutamide also reduced metastatic burden following cardiac injection. Finally, in a comparison of ER(+)/AR(+) primary tumors versus patient-matched local recurrences or distant metastases, AR expression was often maintained even when ER was reduced or absent. These data provide preclinical evidence that anti-androgens that inhibit AR nuclear localization affect both AR and ER, and are effective in combination with current breast cancer therapies. In addition, single-agent efficacy may be possible in tumors resistant to traditional endocrine therapy, as clinical specimens of recurrent disease demonstrate AR expression in tumors with absent or refractory ER.

  9. Methods of analysis for chemicals that disrupt cellular signaling pathways: risk assessment for potential endocrine disruptors.

    PubMed

    Umezawa, Yoshio; Ozawa, Takeaki; Sato, Moritoshi; Inadera, Hidekuni; Kaneko, Shuichi; Kunimoto, Manabu; Hashimoto, Shin-ichi

    2005-01-01

    Here we present a basic concept and several examples of methods of analysis for chemicals that disrupt cellular signaling pathways, in view of risk assessment for potential endocrine disrupting chemicals (EDCs). The key cellular signaling pathways include 1) ER/coactivator interaction, 2) AR translocation into the nucleus, 3) ER/NO/sGC/cGMP, 4) ER/Akt, 5) ER/Src, 6)ER/Src/Grb2, and 7) ER/Ca2+/CaM/CaMK pathways. These were visualized in relevant live cells using newly developed fluorescent and bioluminescent probes. Changes in cellular signals were thereby observed in nongenomic pathways of steroid hormones upon treatment of the target cells with steroid hormones and related chemicals. This method of analysis appears to be a rational approach to high-throughput prescreening (HTPS) of biohazardous chemicals, EDCs, in particular. Also described was the screening of gene expression by serial analysis of gene expression and gene chips upon applying EDCs to breast cancer cells, mouse livers, and human neuroblastoma NB-1 cells.

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

    PubMed Central

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

    2017-01-01

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

  11. Defect structures and optical characteristics of Er3+ ion in Er:LiNbO3 crystals

    NASA Astrophysics Data System (ADS)

    Qian, Yannan; Wang, Rui; Wang, Biao; Xu, Chao; Xing, Lili; Xu, Yanling

    2013-03-01

    Congruent Er:LiNbO3 crystals were grown by Czochraski method. The OH- absorption and UV-vis-near infrared absorption spectra indicated that Er3+ cluster sites were formed in LiNbO3 crystal doped with 3 mol% Er3+ ions. Studies on the stokes and anti-stokes spectra showed that the formation of Er3+ cluster sites could increase the rate of cross relaxation processes. Judd-Ofelt theory was carried out to discuss the spectral characteristics of Er3+ ions in Er:LiNbO3 crystals. Based on Füchtbauer-Ladenburg and McCumber theory, the emission cross section of the 4I13/2 → 4I15/2 transition of Er3+ ion was calculated, and the potential laser performance was evaluated by the gain cross section spectra. Er:LiNbO3 crystal codoped with Zn2+ ions was also grown to discuss the relation between the defect structure and optical characteristics of Er3+ ion.

  12. Efficient 1645-nm Er:YAG laser

    NASA Astrophysics Data System (ADS)

    Young, York E.; Setzler, Scott D.; Snell, Kevin J.; Budni, Peter A.; Pollak, Thomas M.; Chicklis, E. P.

    2004-05-01

    We report a resonantly fiber-laser-pumped Er:YAG laser operating at the eye-safe wavelength of 1645 nm, exhibiting 43% optical efficiency and 54% incident slope efficiency and emitting 7-W average power when repetitively Q switched at 10 kHz. To our knowledge, this is the best performance (conversion efficiency and average power) obtained from a bulk solid-state Q-switched erbium laser. At a 1.1-kHz pulse repetition frequency the laser produces 3.4-mJ pulses with a corresponding peak power of 162 kW. Frequency doubling to produce 822.5-nm, 4.7-kW pulses at 10 kHz was performed to demonstrate the laser's utility.

  13. ER@CEBAF: Modeling code developments

    SciTech Connect

    Meot, F.; Roblin, Y.

    2016-04-13

    A proposal for a multiple-pass, high energy, energy-recovery experiment using CEBAF is under preparation in the frame of a JLab-BNL collaboration. In view of beam dynamics investigations regarding this project, in addition to the existing model in use in Elegant a version of CEBAF is developed in the stepwise ray-tracing code Zgoubi, Beyond the ER experiment, it is also planned to use the latter for the study of polarization transport in the presence of synchrotron radiation, down to Hall D line where a 12 GeV polarized beam can be delivered. This Note briefly reports on the preliminary steps, and preliminary outcomes, based on an Elegant to Zgoubi translation.

  14. Final Technical Report for Award # ER64999

    SciTech Connect

    Metcalf, William W.

    2014-10-08

    This report provides a summary of activities for Award # ER64999, a Genomes to Life Project funded by the Office of Science, Basic Energy Research. The project was entitled "Methanogenic archaea and the global carbon cycle: a systems biology approach to the study of Methanosarcina species". The long-term goal of this multi-investigator project was the creation of integrated, multiscale models that accurately and quantitatively predict the role of Methanosarcina species in the global carbon cycle under dynamic environmental conditions. To achieve these goals we pursed four specific aims: (1) genome sequencing of numerous members of the Order Methanosarcinales, (2) identification of genomic sources of phenotypic variation through in silico comparative genomics, (3) elucidation of the transcriptional networks of two Methanosarcina species, and (4) development of comprehensive metabolic network models for characterized strains to address the question of how metabolic models scale with genetic distance.

  15. Spectroscopy of the Er-doped lithium tetraborate glasses

    NASA Astrophysics Data System (ADS)

    Padlyak, B. V.; Lisiecki, R.; Ryba-Romanowski, W.

    2016-04-01

    The electron paramagnetic resonance (EPR), optical absorption, and luminescence (emission and excitation) spectra as well as luminescence kinetics of the Er-doped glasses with Li2B4O7 composition were investigated and analysed. The high optical quality glasses with Li2B4O7:Er composition containing 0.5 and 1.0 mol.% Er2O3 were obtained from corresponding polycrystalline compound by standard glass synthesis. The EPR spectroscopy in the 4.2-300 K temperature range and optical spectroscopy at 300 K show that the Er impurity is incorporated into the network of Li2B4O7 glass as Er3+ (4f11, 4I15/2) ions, exclusively. The local structure of the Er3+ luminescence centres in Li sites of the glass network is proposed. Based on the standard Judd-Ofelt theory the oscillator strength (Pcal) and experimental oscillator strength (Pexp) for observed absorption transitions as well as phenomenological intensity parameters (Ω2, Ω4, Ω6) for Er3+ centres in the Li2B4O7:Er glass containing 1.0 mol.% Er2O3 were calculated. Spectroscopic parameters of relevance for laser applications, including emission probabilities of transitions (Wr), branching ratios (β), and radiative lifetime (τrad) have been calculated for main observed emission transitions of the Er3+ centres in Li2B4O7:Er glasses. Experimental and calculated lifetimes were compared and quantum efficiency (η) for green (4S3/2 → 4I15/2 transition) and infrared (4I13/2 → 4I15/2 transition) emission bands has been estimated.

  16. Loss of a Clueless-dGRASP complex results in ER stress and blocks Integrin exit from the perinuclear endoplasmic reticulum in Drosophila larval muscle

    PubMed Central

    Wang, Zong-Heng; Rabouille, Catherine; Geisbrecht, Erika R.

    2015-01-01

    Drosophila Clueless (Clu) and its conserved orthologs are known for their role in the prevention of mitochondrial clustering. Here, we uncover a new role for Clu in the delivery of integrin subunits in muscle tissue. In clu mutants, αPS2 integrin, but not βPS integrin, abnormally accumulates in a perinuclear endoplasmic reticulum (ER) subdomain, a site that mirrors the endogenous localization of Clu. Loss of components essential for mitochondrial distribution do not phenocopy the clu mutant αPS2 phenotype. Conversely, RNAi knockdown of the Drosophila Golgi reassembly and stacking protein GRASP55/65 (dGRASP) recapitulates clu defects, including the abnormal accumulation of αPS2 and larval locomotor activity. Both Clu and dGRASP proteins physically interact and loss of Clu displaces dGRASP from ER exit sites, suggesting that Clu cooperates with dGRASP for the exit of αPS2 from a perinuclear subdomain in the ER. We also found that Clu and dGRASP loss of function leads to ER stress and that the stability of the ER exit site protein Sec16 is severely compromised in the clu mutants, thus explaining the ER accumulation of αPS2. Remarkably, exposure of clu RNAi larvae to chemical chaperones restores both αPS2 delivery and functional ER exit sites. We propose that Clu together with dGRASP prevents ER stress and therefore maintains Sec16 stability essential for the functional organization of perinuclear early secretory pathway. This, in turn, is essential for integrin subunit αPS2 ER exit in Drosophila larval myofibers. PMID:25862246

  17. Characterizing heterogeneous coastal groundwater pathways using multi-scale onshore-to-offshore electrical resistivity surveys

    NASA Astrophysics Data System (ADS)

    Befus, K. M.; Cardenas, M.; Tait, D. R.; Erler, D.

    2013-12-01

    Electrical resistivity (ER) imaging techniques are useful for investigating porewater salinity distributions and dynamics within coastal environments. However, complex coastal geology can obscure the hydrologic target of ER surveys. We investigated the geologic controls on groundwater pathways in Rarotonga, a high volcanic island with a carbonate fringe. We used three ER survey configurations to explore this hydrogeologic setting: 1) waterborne, continuous resistivity profiling in the lagoon, 2) submerged cable surveys across the terrestrial-marine interface, and 3) traditional surveys on land. We designed overlapping portions of these surveys to reveal differences in how the deployment methods image subsurface ER structure. Using both the field data and forward modeling, we quantified the resolvability of ER features imaged by overlapping configurations, where the sensitivity changed both as a function of electrode spacing and boundary conditions (i.e. influence of seawater). Waterborne ER results revealed large scale variations in the ER structure of the lagoon geology. These heterogeneities are products of Rarotonga's volcanic history and reef diagenesis that change both the electrical signature and hydrogeologic properties of the subsurface. Time-lapse, submersed ER surveys imaged groundwater salinity dynamics and resolved select ER features more effectively than the waterborne surveys. Terrestrial ER surveys traced the extent of the freshwater lens and the transition from the unsaturated-saturated conditions, i.e., the water table. The ER responses of the three field configurations were concordant but imaged different scales hydrogeologic variability. The unique spatial signatures of both methodology and the geologic setting must be incorporated into future coastal ER applications.

  18. Selective disruption of ER{alpha} DNA-binding activity alters uterine responsiveness to estradiol.

    PubMed

    Hewitt, Sylvia C; O'Brien, Jeanne E; Jameson, J Larry; Kissling, Grace E; Korach, Kenneth S

    2009-12-01

    In vitro models have been used to demonstrate that estrogen receptors (ERs) can regulate estrogen-responsive genes either by directly interacting with estrogen-responsive element (ERE) DNA motifs or by interacting with other transcription factors such as AP1. In this study, we evaluated estrogen (E(2))-dependent uterine gene profiles by microarray in the KIKO mouse, an in vivo knock-in mouse model that lacks the DNA-binding function of ERalpha and is consequently restricted to non-ERE-mediated responses. The 2- or 24-h E(2)-mediated uterine gene responses were distinct in wild-type (WT), KIKO, and alphaERKO genotypes, indicating that unique sets of genes are regulated by ERE and non-ERE pathways. After 2 h E(2) treatment, 38% of the WT transcripts were also regulated in the KIKO, demonstrating that the tethered mechanism does operate in this in vivo model. Surprisingly, 1438 E(2)-regulated transcripts were unique in the KIKO mouse and were not seen in either WT or alphaERKO. Pathway analyses revealed that some canonical pathways, such as the Jak/Stat pathway, were affected in a similar manner by E(2) in WT and KIKO. In other cases, however, the WT and KIKO differed. One example is the Wnt/beta-catenin pathway; this pathway was impacted, but different members of the pathway were regulated by E(2) or were regulated in a different manner, consistent with differences in biological responses. In summary, this study provides a comprehensive analysis of uterine genes regulated by E(2) via ERE and non-ERE pathways.

  19. The Electrocardiogram of an ER Patient With Chest Pain

    PubMed Central

    Panneerselvam, Arunkumar; Ananthakrishna, Rajiv; Bhat, Prabhavathi; Nanjappa, Manjunath C

    2011-01-01

    The electrocardiogram (ECG) is an essential investigation in the evaluation of chest pain in the emergency room (ER). Correct interpretation of the ECG findings, determines the diagnosis and management strategy. This ECG spot diagnosis will improve the skills of the residents and physicians working in ER.

  20. CW YVO4:Er Laser with Resonant Pumping

    NASA Astrophysics Data System (ADS)

    Gorbachenya, K. N.; Kisel, V. E.; Yasukevich, A. S.; Matrosov, V. N.; Tolstik, N. A.; Kuleshov, N. V.

    2015-05-01

    The lasing characteristics of a YVO4:Er laser with resonant pumping in the 1.5-1.6 μm range are studied. Lasing is obtained at λ = 1603 nm with a differential efficiency of up to 61%. YVO4:Er crystals are found to offer promise for use in efficient resonantly (in-band) pumped lasers.

  1. Reaction Diffusion Modeling of Calcium Dynamics with Realistic ER Geometry

    PubMed Central

    Means, Shawn; Smith, Alexander J.; Shepherd, Jason; Shadid, John; Fowler, John; Wojcikiewicz, Richard J. H.; Mazel, Tomas; Smith, Gregory D.; Wilson, Bridget S.

    2006-01-01

    We describe a finite-element model of mast cell calcium dynamics that incorporates the endoplasmic reticulum's complex geometry. The model is built upon a three-dimensional reconstruction of the endoplasmic reticulum (ER) from an electron tomographic tilt series. Tetrahedral meshes provide volumetric representations of the ER lumen, ER membrane, cytoplasm, and plasma membrane. The reaction-diffusion model simultaneously tracks changes in cytoplasmic and ER intraluminal calcium concentrations and includes luminal and cytoplasmic protein buffers. Transport fluxes via PMCA, SERCA, ER leakage, and Type II IP3 receptors are also represented. Unique features of the model include stochastic behavior of IP3 receptor calcium channels and comparisons of channel open times when diffusely distributed or aggregated in clusters on the ER surface. Simulations show that IP3R channels in close proximity modulate activity of their neighbors through local Ca2+ feedback effects. Cytoplasmic calcium levels rise higher, and ER luminal calcium concentrations drop lower, after IP3-mediated release from receptors in the diffuse configuration. Simulation results also suggest that the buffering capacity of the ER, and not restricted diffusion, is the predominant factor influencing average luminal calcium concentrations. PMID:16617072

  2. ER-stress in Alzheimer’s disease: turning the scale?

    PubMed Central

    Endres, Kristina; Reinhardt, Sven

    2013-01-01

    Pathogenic mechanisms of Alzheimer’s disease (AD) are intensely investigated as it is the most common form of dementia and burdens society by its costs and social demands. While key molecules such as A-beta peptides and tau have been identified decades ago, it is still enigmatic what drives the disease in its sporadic manifestation. Synthesis of A-beta peptides as well as phosphorylation of tau proteins comprise normal cellular functions and occur in principle in the healthy as well as in dementia-affected persons. Dyshomeostasis of Amyloid Precursor Protein (APP) cleavage, energy metabolism or kinase/phosphatase activity due to stressors has been suggested as a trigger of the disease. One way for cells to escape stress based on dysfunction of ER is the unfolded protein response - the UPR. This pathway is composed out of three different routes that differ in proteins involved, targets and consequences for cell fate: activation of transmembrane ER resident kinases IRE1-alpha and PERK or monomerization of membrane-anchored activating transcription factor 6 (ATF6) induce activation of versatile transcription factors (XBP-1, eIF2-alpha/ATF4 and ATF6 P50). These bind to specific DNA sequences on target gene promoters and on one hand attenuate general ER-prone protein synthesis and on the other equip the cell with tools to de-stress. If cells fail in stress compensation, this signaling also is able to evoke apoptosis. In this review we summarized knowledge on how APP processing and phosphorylation of tau might be influenced by ER-stress signaling. In addition, we depicted the effects UPR itself seems to have on molecules closely related to AD and describe what is known about UPR in AD animal models as well as in human patients. PMID:24319643

  3. Smart structures for shock wave attenuation using ER inserts

    NASA Astrophysics Data System (ADS)

    Kim, Jaehwan; Kim, Jung-Yup; Choi, Seung-Bok; Kim, Kyung-Su

    2001-08-01

    This Paper demonstrates the possibility of shock wave attenuation propagating through a smart structure that incorporates ER insert. The wave transmission of ER inserted beam is theoretically derived using Mead & Markus model and the theoretical results are compared with the finite element analysis results. To experimentally verify the shock wave attenuation, ER insert in an aluminum plate is made and two piezoceramic disks are used as transmitter and receiver of the wave. The transmitter sends a sine pulse signal such that a component of shock wave travels through the plate structure and the receiver gets the transmitted wave signal. Wave propagation of the ER insert can be adjusted by changing the applied electric field on the ER insert. Details of the experiment are addressed and the possibility of shock wave attenuation is experimentally verified. This kind of smart structure can be used for warship and submarine hull structures to protect fragile and important equipment.

  4. Ce(IV) -Gd(III) Mixed Oxides as Hosts for Er(III) -Based Upconversion Phosphors.

    PubMed

    Sorbello, Cecilia; Gross, Petra; Strassert, Cristian A; Jobbágy, Matías; Barja, Beatriz C

    2017-03-23

    A family of Er(III) and Er(III) -Yb(III) based nanophosphors, hosted in monophasic oxidic Ce(IV) -Gd(III) binary solid solutions, was prepared. The samples were formulated with a constant Er(III) content as the activator, with the eventual addition of Yb(III) as a sensitizer. The amorphous Ce0.94-x Gdx Er0.06 (OH)CO3 ⋅H2 O and Ce0.94-x Gdx Er0.05 Yb0.01 (OH)CO3 ⋅H2 O precursors were prepared by following the urea method to obtain monodispersed spheres of tunable size ranging from 30 to 450 nm. After being decomposed at 1273 K under an atmosphere of air, the precursors of 200 nm in diameter evolved into monophasic polycrystalline particles preserving the parent shape and size. The role of the composition of the binary matrices in the emission properties was evaluated for two different excitation wavelengths (976 nm and 780 nm) based on the upconversion (UC) emission spectra and their dependence on the incident power. The yield of the UC process is discussed in the framework of established and novel alternative mechanisms. The number of vacancies and mainly the symmetry of the Er(III) environment play major roles in the deactivation pathways of the UC emission mechanisms. However, the colours obtained by employing bare Ce(IV) or Gd(III) hosts are preserved in the related monophasic Ce(IV) -rich or Gd(III) -rich binary hosts.

  5. Clerkship pathway

    PubMed Central

    MacLellan, Anne-Marie; Brailovsky, Carlos; Miller, François; Leboeuf, Sylvie

    2012-01-01

    Abstract Objective To identify factors that help predict success for international medical graduates (IMGs) who train in Canadian residency programs and pass the Canadian certification examinations. Design A retrospective analysis of 58 variables in the files of IMGs who applied to the Collège des médecins du Québec between 2000 and 2008. Setting Quebec. Participants Eight hundred ten IMGs who applied to the Collège des médecins du Québec through either the “equivalency pathway” (ie, starting training at a residency level) or the “clerkship pathway” (ie, relearning at the level of a medical student in the last 2 years of the MD diploma). Main outcome measures Success factors in achieving certification. Data were analyzed using descriptive statistics and ANOVA (analysis of variance). Results International medical graduates who chose the “clerkship pathway” had greater success on certification examinations than those who started at the residency level did. Conclusion There are several factors that influence IMGs’ success on certification examinations, including integration issues, the acquisition of clinical decision-making skills, and the varied educational backgrounds. These factors perhaps can be better addressed by a regular clerkship pathway, in which IMGs benefit from learner-centred teaching and have more time for reflection on and understanding of the North American approach to medical education. The clerkship pathway is a useful strategy for assuring the integration of IMGs in the North American health care system. A 2-year relearning period in medical school at a clinical clerkship level deserves careful consideration. PMID:22859630

  6. LIS Validation at The KSC-ER

    NASA Technical Reports Server (NTRS)

    Koshak, William J.; Krider, E. P.; Arnold, James E. (Technical Monitor)

    2000-01-01

    Each year, thousands of lightning electric field disturbances are recorded and archived by the ground-based field mill (FM) network at the NASA Kennedy Space Center (KSC) and USAF Eastern Range (ER). The FM network has a range of several tens of kilometers, and a digital accuracy of 4 V/m. It has provided years of continuous lightning warning surveillance to KSC-ER space vehicle launch operations, and has undergone one major hardware upgrade since its inception in the early 1970s. Additional KSC lightning warning data is derived from a multistation radio time-of-arrival system called Lightning Detection and Ranging (LDAR). This system provides the location and space-time mapping of individual lightning channels (for both cloud and ground flashes). Additional lightning information for the KSC region is available from the National Lightning Detection Network (NLDN) and a 5-station local magnetic direction finder network. In this study, all of the above mentioned data are used to ground-validate data derived from the Lightning Imaging Sensor (LIS) onboard the Tropical Rainfall Measuring Mission (TRMM). The FM network can be used to retrieve the charges deposited in a lightning flash, provided the flash is within a few kilometers of the FM Network. Although it is rare to obtain a TRMM overpass of thunderstorms hat occur this close to the FM network, seven such storms have been found and examined in this study. We compare the times and locations of LIS optical pulses with the spatial-temporal character of the FM, LDAR, and magnetic direction finder data. We also inter-compare LIS optical pulse amplitude data with FM-derived charge magnitudes, number of LDAR radio sources, and peak current values from magnetic direction finder data. Generally speaking, LIS lightning locations and times agree favorably with the KSC ground-based systems for most cases, but little correlation appears to exist between optical pulse amplitude and any of charge, # LDAR sources, peak current

  7. Dielectronic recombination of Er-like tungsten

    NASA Astrophysics Data System (ADS)

    Safronova, U. I.; Safronova, A. S.

    2012-03-01

    Theoretical studies of dielectronic recombination, a very important process for both atomic and plasma physics, are carried out for low-ionized Er-like W. The dielectronic recombination (DR) of the Er-like ion W6+ proceeds via electron capture into the intermediate autoionizing states of the Tm-like ion W5+ followed by the radiative decay to singly-excited bound states. In particular, energy levels, radiative transition probabilities, and autoionization rates for [Cd]4f145p55l'nl, [Cd]4f145p56l''nl, [Cd]4f135p65l'nl, and [Cd]4f135p66l''nl (l'=d,f,g, l''=s,p,d,f,g, n=5-7) states in Tm-like tungsten (W5+) are calculated using the relativistic many-body perturbation theory and relativistic all-order single-double method as well as the Hartree-Fock-relativistic method (cowan code). Branching ratios relative to the first threshold and intensity factors are calculated for satellite lines. DR rate coefficients are determined for the singly-excited [Cd]4f145p6nl (n=5-7) and nonautoionizing doubly-excited [Cd]4f145p55d2, [Cd]4f135p65d2, [Cd]4f135p66s2, [Cd]4f135p65d6s, and [Cd]4f135p65d6p states. Also, contributions from the autoionizing doubly-excited [Cd]4f145p55l'nl, [Cd]4f145p56l''nl, [Cd]4f135p65l'nl, and [Cd]4f135p66l''nl states (with n up to 100), which are very important for calculating total DR rates, are estimated. Synthetic dielectronic satellite spectra from Tm-like W are simulated in a broad spectral range from 140 to 1200 Å. These relativistic calculations provide recommended values critically evaluated for their accuracy for a number of W5+ ion properties useful for a variety of applications, including for fusion applications.

  8. Ultraviolet upconversion fluorescence of Er3+ in Yb3+/Er3+-codoped Gd2O3 nanotubes.

    PubMed

    Zheng, Kezhi; Zhao, Dan; Zhang, Daisheng; Liu, Zhenyu; Qin, Weiping

    2011-11-01

    Under 980 nm excitation, room-temperature ultraviolet (UV) upconversion (UC) emissions of Er3+ from the 4G(9/2), 2K(13/2), and 2P(3/2) states were observed in Gd2O3:Yb3+/Er3+ nanotubes, which were synthesized via a simple wet-chemical route at low temperature and ambient pressure followed by a subsequent heat treatment at 800 degrees C. The experimental results exhibited that these UV emissions came from four-photon UC processes. In the Gd2O3:Yb3+/Er3+ nanocrystals, the energy transfers (ETs) from Yb3+ to Er3+ played important roles in populating the high-energy states of Er3+ ions. This material provides a possible candidate for building UV compact solid-state lasers or fiber lasers.

  9. Effects of silicon nanostructure evolution on Er{sup 3+} luminescence in silicon-rich silicon oxide/Er-doped silica multilayers

    SciTech Connect

    Chang, Jee Soo; Jhe, Ji-Hong; Yang, Moon-Seung; Shin, Jung H.; Kim, Kyung Joong; Moon, Dae Won

    2006-10-30

    The effect of silicon nanostructure evolution on Er{sup 3+} luminescence is investigated by using multilayers of 2.5 nm thin SiO{sub x} (x<2) and 10 nm thin Er-doped silica (SiO{sub 2}:Er). By separating excess Si and Er atoms into separate, nanometer-thin layers, the effect of silicon nanostructure evolution on np-Si sensitized Er{sup 3+} luminescence could be investigated while keeping the microscopic Er{sup 3+} environment the same. The authors find that while the presence of np-Si is necessary for efficient sensitization, the overall quality of np-Si layer has little effect on the Er{sup 3+} luminescence. On the other hand, intrusion of np-Si into Er-doped silica layers leads to deactivation of np-Si/Er{sup 3+} interaction, suggesting that there is a limit to excess Si and Er contents that can be used.

  10. Reducing Smad3/ATF4 was essential for Sirt1 inhibiting ER stress-induced apoptosis in mice brown adipose tissue.

    PubMed

    Liu, Zhenjiang; Gu, Huihui; Gan, Lu; Xu, Yatao; Feng, Fei; Saeed, Muhammad; Sun, Chao

    2017-02-07

    Sirtuin 1 (Sirt1) promotes adaptive thermogenesis by controlling the acetylation status of enzymes and transcriptional factors in interscapular brown adipose tissue (iBAT). However, the effects of Sirt1 on endoplasmic reticulum (ER) stress and apoptosis of iBAT remain elusive. In this study, the mRNA levels of Sirt1 and thermogenesis genes were reduced but the genes related with ER stress were elevated in iBAT of high-fat diet (HFD)-induced obese mice. Moreover, ER stress further inhibited mRNA level of Sirt1 and triggered brown adipocyte apoptosis in vitro and in vivo. Further analysis revealed that Sirt1 overexpression alleviated ER stress-induced brown adipocyte apoptosis by inhibiting Smad3 and ATF4. In addition, Smad3 bound to ATF4 promoter region and positively transcriptional regulation of ATF4. Our data also confirmed that Sirt1 reduced early apoptotic cells and blocked the mitochondrial apoptosis pathway by directly interacting with ATF4. Furthermore, Sirt1 attenuated tunicamycin-induced cold intolerance and elevating thermogenesis by inhibiting ER stress and apoptosis in iBAT. In summary, our data collectively revealed Sirt1 reduced ER stress and apoptosis of brown adipocyte in vivo and in vitro by inhibiting Smad3/ATF4 signal. These data reveal a novel mechanism that links Sirt1 to brown adipocyte apoptosis.

  11. Targeted siRNA Screens Identify ER-to-Mitochondrial Calcium Exchange in Autophagy and Mitophagy Responses in RPE1 Cells.

    PubMed

    MacVicar, Thomas D B; Mannack, Lilith V J C; Lees, Robert M; Lane, Jon D

    2015-06-11

    Autophagy is an important stress response pathway responsible for the removal and recycling of damaged or redundant cytosolic constituents. Mitochondrial damage triggers selective mitochondrial autophagy (mitophagy), mediated by a variety of response factors including the Pink1/Parkin system. Using human retinal pigment epithelial cells stably expressing autophagy and mitophagy reporters, we have conducted parallel screens of regulators of endoplasmic reticulum (ER) and mitochondrial morphology and function contributing to starvation-induced autophagy and damage-induced mitophagy. These screens identified the ER chaperone and Ca2+ flux modulator, sigma non-opioid intracellular receptor 1 (SIGMAR1), as a regulator of autophagosome expansion during starvation. Screens also identified phosphatidyl ethanolamine methyl transferase (PEMT) and the IP3-receptors (IP3Rs) as mediators of Parkin-induced mitophagy. Further experiments suggested that IP3R-mediated transfer of Ca2+ from the ER lumen to the mitochondrial matrix via the mitochondrial Ca2+ uniporter (MCU) primes mitochondria for mitophagy. Importantly, recruitment of Parkin to damaged mitochondria did not require IP3R-mediated ER-to-mitochondrial Ca2+ transfer, but mitochondrial clustering downstream of Parkin recruitment was impaired, suggesting involvement of regulators of mitochondrial dynamics and/or transport. Our data suggest that Ca2+ flux between ER and mitochondria at presumed ER/mitochondrial contact sites is needed both for starvation-induced autophagy and for Parkin-mediated mitophagy, further highlighting the importance of inter-organellar communication for effective cellular homeostasis.

  12. Targeted siRNA Screens Identify ER-to-Mitochondrial Calcium Exchange in Autophagy and Mitophagy Responses in RPE1 Cells

    PubMed Central

    MacVicar, Thomas D. B.; Mannack, Lilith V. J. C.; Lees, Robert M.; Lane, Jon D.

    2015-01-01

    Autophagy is an important stress response pathway responsible for the removal and recycling of damaged or redundant cytosolic constituents. Mitochondrial damage triggers selective mitochondrial autophagy (mitophagy), mediated by a variety of response factors including the Pink1/Parkin system. Using human retinal pigment epithelial cells stably expressing autophagy and mitophagy reporters, we have conducted parallel screens of regulators of endoplasmic reticulum (ER) and mitochondrial morphology and function contributing to starvation-induced autophagy and damage-induced mitophagy. These screens identified the ER chaperone and Ca2+ flux modulator, sigma non-opioid intracellular receptor 1 (SIGMAR1), as a regulator of autophagosome expansion during starvation. Screens also identified phosphatidyl ethanolamine methyl transferase (PEMT) and the IP3-receptors (IP3Rs) as mediators of Parkin-induced mitophagy. Further experiments suggested that IP3R-mediated transfer of Ca2+ from the ER lumen to the mitochondrial matrix via the mitochondrial Ca2+ uniporter (MCU) primes mitochondria for mitophagy. Importantly, recruitment of Parkin to damaged mitochondria did not require IP3R-mediated ER-to-mitochondrial Ca2+ transfer, but mitochondrial clustering downstream of Parkin recruitment was impaired, suggesting involvement of regulators of mitochondrial dynamics and/or transport. Our data suggest that Ca2+ flux between ER and mitochondria at presumed ER/mitochondrial contact sites is needed both for starvation-induced autophagy and for Parkin-mediated mitophagy, further highlighting the importance of inter-organellar communication for effective cellular homeostasis. PMID:26110381

  13. The anti-metastatic effects of the phytoestrogen arctigenin on human breast cancer cell lines regardless of the status of ER expression.

    PubMed

    Maxwell, Thressi; Chun, So-Young; Lee, Kyu-Shik; Kim, Soyoung; Nam, Kyung-Soo

    2017-02-01

    Arctigenin is a plant lignan extracted from Arctium lappa that has been shown to have estrogenic properties. In spite of the health benefits of phytoestrogens reducing the risk of osteoporosis, heart disease, and menopausal symptoms, its benefits against the risk of breast cancer have not been fully elucidated. Thus, we investigated the effects of arctigenin on metastasis of breast cancer using both estrogen receptor (ER)-positive MCF-7 and ER-negative MDA-MB-231 human breast cancer cell lines to see if the effects are dependent on the status of ER expression. In ER-positive MCF-7 cells, arctigenin efficiently inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced cell migration and invasion. The activity of crucial metastatic protease matrix metalloprotease (MMP)-9 in gelatin zymography was also efficiently decreased by arctigenin, as well as its mRNA expression. Notably, arctigenin exhibited similar anti-metastatic effects even in ER-negative MDA-MB-231 cells, suggesting that the anti-metastatic effects of arctigenin were not exerted via the ER. The upstream signaling pathways involved in the regulation of MMP-9 and urokinase plasminogen activator (uPA) were analyzed using western blotting. The activation of Akt, NF-κB and MAPK (ERK 1/2 and JNK 1/2) was found to be inhibited. Taken together, these data suggest that arctigenin confers anti-metastatic effects by inhibiting MMP-9 and uPA via the Akt, NF-κB and MAPK signaling pathways on breast cancer, regardless of ER expression. Therefore, we propose that the intake of arctigenin could be an effective supplement for breast cancer patients.

  14. Up Conversion Measurements in Er:YAG; Comparison with 1.6 Micrometer Laser Performance

    NASA Technical Reports Server (NTRS)

    Barnes, Norman P.; Walsh, Brian M.; Amzajerdian, Farzin; Reichle, Donald J.; Busch, George E.; Carrion, William A.

    2011-01-01

    Up conversion significantly affects Er:YAG lasers. Measurements performed here for low Er concentration are significantly different than reported high Er concentration. The results obtained here are used to predict laser performance and are compared with experimental results.

  15. ICF Program: LDRD-ER Final Report

    SciTech Connect

    Glenzer, S H

    2004-02-05

    In the 01-ERD-107 LDRD-ER project, we have performed novel Thomson scattering experiments at the Trident and Omega laser facilities and provided high quality spectral data. These results have led to the development of the first quantitative understanding of laser-plasma interactions for NIF plasmas. For this purpose an green/ultraviolet probe laser, built for Nova in 1998 [1] and successfully used to measure both temperature and plasma wave amplitudes [2], has been deployed on Omega. The Thomson scattering diagnostics has been used twofold: (1) it provided independent measurements of the plasma electron and ion temperature, the plasma flow velocity, or the electron distribution function; (2) it provided measurements of the primary plasma wave and their secondary non-linear decay wave products. These experiments at Omega provide definitive quantitative results on the nonlinear saturation of stimulated Raman scattering for green (2{omega}) beams. In addition, the experiments on the Trident laser have led to a quantitative understanding of the stimulated Brillouin scattering in low-Z plasmas. A nonlinear frequency detuning model has successfully explained all the experimental observable including the SBS reflectivity. This model has been implemented into the laser-plasma interaction code pF3D as a tool to design and optimize NIF target experiments with SBS and SRS losses included. The development of quantitative models for SBS and SRS for various regimes has now been adopted as part of the WBS1 project within the ICF program.

  16. Genetic variations in vitamin D-related pathways and breast cancer risk in African American women in the AMBER consortium.

    PubMed

    Yao, Song; Haddad, Stephen A; Hu, Qiang; Liu, Song; Lunetta, Kathryn L; Ruiz-Narvaez, Edward A; Hong, Chi-Chen; Zhu, Qianqian; Sucheston-Campbell, Lara; Cheng, Ting-Yuan David; Bensen, Jeannette T; Johnson, Candace S; Trump, Donald L; Haiman, Christopher A; Olshan, Andrew F; Palmer, Julie R; Ambrosone, Christine B

    2016-05-01

    Studies of genetic variations in vitamin D-related pathways and breast cancer risk have been conducted mostly in populations of European ancestry, and only sparsely in African Americans (AA), who are known for a high prevalence of vitamin D deficiency. We analyzed 24,445 germline variants in 63 genes from vitamin D-related pathways in the African American Breast Cancer Epidemiology and Risk (AMBER) consortium, including 3,663 breast cancer cases and 4,687 controls. Odds ratios (OR) were derived from logistic regression models for overall breast cancer, by estrogen receptor (ER) status (1,983 ER positive and 1,098 ER negative), and for case-only analyses of ER status. None of the three vitamin D-related pathways were associated with breast cancer risk overall or by ER status. Gene-level analyses identified associations with risk for several genes at a nominal p ≤ 0.05, particularly for ER- breast cancer, including rs4647707 in DDB2. In case-only analyses, vitamin D metabolism and signaling pathways were associated with ER- cancer (pathway-level p = 0.02), driven by a single gene CASR (gene-level p = 0.001). The top SNP in CASR was rs112594756 (p = 7 × 10(-5), gene-wide corrected p = 0.01), followed by a second signal from a nearby SNP rs6799828 (p = 1 × 10(-4), corrected p = 0.03). In summary, several variants in vitamin D pathways were associated with breast cancer risk in AA women. In addition, CASR may be related to tumor ER status, supporting a role of vitamin D or calcium in modifying breast cancer phenotypes.

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

    PubMed

    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.

  18. Electroreduction of Er 3+ in nonaqueous solvents

    SciTech Connect

    Small, Leo J.; Sears, Jeremiah M.; Lambert, Timothy N.; Boyle, Timothy J.; Hess, Ryan F.

    2016-09-15

    Here, the electroreduction of Er3+ in propylene carbonate, N,N-dimethylformamide, or a variety of quaternary ammonium ionic liquids (ILs) was investigated using [Er(OTf)3] and [Er(NTf2)3]. Systematic variation of the ILs' cation and anion, Er3+ salt, and electrode material revealed a disparity in electrochemical interactions not previously seen. For most ILs at a platinum electrode, cyclic voltammetry exhibits irreversible interactions between Er3+ salts and the electrode at potentials significantly less than the theoretical reduction potential for Er3+. Throughout all solvent–salt systems tested, a deposit could be formed on the electrode, though obtaining a high purity, crystalline Er0 deposit is challenging due to the extreme reactivity of the deposit and resulting chemical interactions, often resulting in the formation of a complex, amorphous solid–electrolyte interface that slowed deposition rates. Comparison of platinum, gold, nickel, and glassy carbon (GC) working electrodes revealed oxidation processes unique to the platinum surface. While no appreciable reduction current was observed on GC at the potentials investigated, deposits were seen on platinum, gold, and nickel electrodes.

  19. Ammonia synthesis and ER-MCFC-technology - a profitable combination?

    SciTech Connect

    Dijkema, G.P.J.; Vervoort, J.; Daniels, R.J.E.; Luteijn, C.P.

    1996-12-31

    Similar to stand-alone ER-MCFC power systems industrial ammonia production facilities include hydrogen-rich synthesis-gas production. Therefore, integration of ER-MCFC stacks in a conventional industrial ammonia plant was investigated. By preliminary process design calculations three promising process structures were evaluated: (1) ER-MCFC is fed by the ammonia plant`s steam-reformer; anode off-gas to firing (2) similar to structure 1; in this case the anode off-gas is redirected to the ammonia process (3) ER-MCFC is fed by ammonia-synthesis purge gas The results indicate that for options 1 and 3 a return-on-investment for the ER-MCFC of around 8% is achievable at a stack cost of $250/kW and a revenue of 7c/kWh. Option 2 is not profitable, because of the associated reduction in ammonia production. The degree of hydrogen-utilization in the ER-MCFC to be selected for maximum profit varies with the process structure and indicates that there is scope for ER-MCFC stacks which operate at low hydrogen-utilization.

  20. Structure and Dynamics of ER: Minimal Networks and Biophysical Constraints

    PubMed Central

    Lin, Congping; Zhang, Yiwei; Sparkes, Imogen; Ashwin, Peter

    2014-01-01

    The endoplasmic reticulum (ER) in live cells is a highly mobile network whose structure dynamically changes on a number of timescales. The role of such drastic changes in any system is unclear, although there are correlations with ER function. A better understanding of the fundamental biophysical constraints on the system will allow biologists to determine the effects of molecular factors on ER dynamics. Previous studies have identified potential static elements that the ER may remodel around. Here, we use these structural elements to assess biophysical principles behind the network dynamics. By analyzing imaging data of tobacco leaf epidermal cells under two different conditions, i.e., native state (control) and latrunculin B (treated), we show that the geometric structure and dynamics of ER networks can be understood in terms of minimal networks. Our results show that the ER network is well modeled as a locally minimal-length network between the static elements that potentially anchor the ER to the cell cortex over longer timescales; this network is perturbed by a mixture of random and deterministic forces. The network need not have globally minimum length; we observe cases where the local topology may change dynamically between different Euclidean Steiner network topologies. The networks in the treated cells are easier to quantify, because they are less dynamic (the treatment suppresses actin dynamics), but the same general features are found in control cells. Using a Langevin approach, we model the dynamics of the nonpersistent nodes and use this to show that the images can be used to estimate both local viscoelastic behavior of the cytoplasm and filament tension in the ER network. This means we can explain several aspects of the ER geometry in terms of biophysical principles. PMID:25099815

  1. Neuronal ER stress impedes myeloid-cell-induced vascular regeneration through IRE1α degradation of netrin-1.

    PubMed

    Binet, François; Mawambo, Gaëlle; Sitaras, Nicholas; Tetreault, Nicolas; Lapalme, Eric; Favret, Sandra; Cerani, Agustin; Leboeuf, Dominique; Tremblay, Sophie; Rezende, Flavio; Juan, Aimee M; Stahl, Andreas; Joyal, Jean-Sebastien; Milot, Eric; Kaufman, Randal J; Guimond, Martin; Kennedy, Timothy E; Sapieha, Przemyslaw

    2013-03-05

    In stroke and proliferative retinopathy, despite hypoxia driven angiogenesis, delayed revascularization of ischemic tissue aggravates the loss of neuronal function. What hinders vascular regrowth in the ischemic central nervous system remains largely unknown. Using the ischemic retina as a model of neurovascular interaction in the CNS, we provide evidence that the failure of reparative angiogenesis is temporally and spatially associated with endoplasmic reticulum (ER) stress. The canonical ER stress pathways of protein kinase RNA-like ER kinase (PERK) and inositol-requiring enzyme-1α (IRE1α) are activated within hypoxic/ischemic retinal ganglion neurons, initiating a cascade that results in angiostatic signals. Our findings demonstrate that the endoribonuclease IRE1α degrades the classical guidance cue netrin-1. This neuron-derived cue triggers a critical reparative-angiogenic switch in neural macrophage/microglial cells. Degradation of netrin-1, by persistent neuronal ER stress, thereby hinders vascular regeneration. These data identify a neuronal-immune mechanism that directly regulates reparative angiogenesis.

  2. Arctic geodynamics: Arctic science and ERS-1 satellite altimetry

    NASA Technical Reports Server (NTRS)

    Anderson, Allen Joel; Sandwell, David T.

    1994-01-01

    A detailed gravity field map of the mid Arctic Ocean, spreading ridge system was produced on the basis of ERS-1 satellite altimetry data. Areas of special concern, the Barents and Kara Seas, and areas surrounding the islands of Svalbard, Frans Josef Land and Novoya Zemlya are reviewed. ERS-1 altimetry covers unique Arctic and Antarctic latitudes above 72 degrees. Before ERS-1 it was not possible to study these areas with satellite altimetry. Gravity field solutions for the Barents Sea, portions of the Arctic Ocean and the Norwegian sea are shown. The largest gravity anomalies occur along the Greenland fracture zone as well as along transform faults near Svalbard.

  3. Harvard ER-2 OH laser-induced fluorescence instrument

    NASA Technical Reports Server (NTRS)

    Wennberg, Paul O.; Anderson, James G.

    1994-01-01

    The Harvard ER-2 OH instrument is scheduled to be integrated into the NASA ER-2 high altitude aircraft ozone payload in August 1992. Design and fabrication is presently underway. This experiment is a descendant of a balloon borne instrument designed and built in the mid-1980s. The ER-2 instrument is being designed to measure OH and HO2 as part of the NASA ozone payload for the investigation of processes controlling the concentration of stratospheric ozone. Although not specifically designed to do so, it is hoped that valid measurements of OH and HO2 can be made in the remote free troposphere with this instrument.

  4. ApoER2 and Reelin are expressed in regenerating peripheral nerve and regulate Schwann cell migration by activating the Rac1 GEF protein, Tiam1.

    PubMed

    Pasten, Consuelo; Cerda, Joaquín; Jausoro, Ignacio; Court, Felipe A; Cáceres, Alfredo; Marzolo, Maria-Paz

    2015-11-01

    ApoER2 and its ligand Reelin participate in neuronal migration during development. Upon receptor binding, Reelin induces the proteolytic processing of ApoER2 as well as the activation of signaling pathway, including small Rho GTPases. Besides its presence in the central nervous system (CNS), Reelin is also secreted by Schwann cells (SCs), the glial cells of the peripheral nervous system (PNS). Reelin deficient mice (reeler) show decreased axonal regeneration in the PNS; however neither the presence of ApoER2 nor the role of the Reelin signaling pathway in the PNS have been evaluated. Interestingly SC migration occurs during PNS development and during injury-induced regeneration and involves activation of small Rho GTPases. Thus, Reelin-ApoER2 might regulate SC migration during axon regeneration in the PNS. Here we demonstrate the presence of ApoER2 in PNS. After sciatic nerve injury Reelin was induced and its receptor ApoER2 was proteolytically processed. In vitro, SCs express both Reelin and ApoER2 and Reelin induces SC migration. To elucidate the molecular mechanism underlying Reelin-dependent SC migration, we examined the involvement of Rac1, a conspicuous small GTPase family member. FRET experiments revealed that Reelin activates Rac1 at the leading edge of SCs. In addition, Tiam1, a major Rac1-specific GEF was required for Reelin-induced SC migration. Moreover, Reelin-induced SC migration was decreased after suppression of the polarity protein PAR3, consistent with its association to Tiam1. Even more interesting, we demonstrated that PAR3 binds preferentially to the full-length cytoplasmic tail of ApoER2 corresponding to the splice-variant containing the exon 19 that encodes a proline-rich insert and that ApoER2 was required for SC migration. Our study reveals a novel function for Reelin/ApoER2 in PNS, inducing cell migration of SCs, a process relevant for PNS development and regeneration.

  5. Return of Collective Rotation in {sup 157}Er and {sup 158}Er at Ultrahigh Spin

    SciTech Connect

    Paul, E. S.; Twin, P. J.; Evans, A. O.; Choy, P. T. W.; Nolan, P. J.; Pipidis, A.; Riley, M. A.; Campbell, D. B.; Simpson, J.; Appelbe, D. E.; Joss, D. T.; Clark, R. M.; Cromaz, M.; Fallon, P.; Goergen, A.; Lee, I. Y.; Macchiavelli, A. O.; Ward, D.; Ragnarsson, I.

    2007-01-05

    A new frontier of discrete-line {gamma}-ray spectroscopy at ultrahigh spin has been opened in the rare-earth nuclei {sup 157,158}Er. Four rotational structures, displaying high moments of inertia, have been identified, which extend up to spin {approx}65({Dirac_h}/2{pi}) and bypass the band-terminating states in these nuclei which occur at {approx}45({Dirac_h}/2{pi}). Cranked Nilsson-Strutinsky calculations suggest that these structures arise from well-deformed triaxial configurations that lie in a valley of favored shell energy which also includes the triaxial strongly deformed bands in {sup 161-167}Lu.

  6. Unconventional Pathways of Secretion Contribute to Inflammation

    PubMed Central

    Daniels, Michael J. D.; Brough, David

    2017-01-01

    In the conventional pathway of protein secretion, leader sequence-containing proteins leave the cell following processing through the endoplasmic reticulum (ER) and Golgi body. However, leaderless proteins also enter the extracellular space through mechanisms collectively known as unconventional secretion. Unconventionally secreted proteins often have vital roles in cell and organism function such as inflammation. Amongst the best-studied inflammatory unconventionally secreted proteins are interleukin (IL)-1β, IL-1α, IL-33 and high-mobility group box 1 (HMGB1). In this review we discuss the current understanding of the unconventional secretion of these proteins and highlight future areas of research such as the role of nuclear localisation. PMID:28067797

  7. Calcium homoeostasis modulator 1 (CALHM1) reduces the calcium content of the endoplasmic reticulum (ER) and triggers ER stress.

    PubMed

    Gallego-Sandín, Sonia; Alonso, María Teresa; García-Sancho, Javier

    2011-08-01

    CALHM1 (calcium homoeostasis modulator 1), a membrane protein with similarity to NMDA (N-methyl-D-aspartate) receptor channels that localizes in the plasma membrane and the ER (endoplasmic reticulum) of neurons, has been shown to generate a plasma-membrane Ca(2+) conductance and has been proposed to influence Alzheimer's disease risk. In the present study we have investigated the effects of CALHM1 on intracellular Ca(2+) handling in HEK-293T [HEK (human embryonic kidney)-293 cells expressing the large T-antigen of SV40 (simian virus 40)] cells by using targeted aequorins for selective monitorization of Ca(2+) transport by organelles. We find that CALHM1 increases Ca(2+) leak from the ER and, more importantly, reduces ER Ca(2+) uptake by decreasing both the transport capacity and the Ca(2+) affinity of SERCA (sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase). As a result, the Ca(2+) content of the ER is drastically decreased. This reduction in the Ca(2+) content of the ER triggered the UPR (unfolded protein response) with induction of several ER stress markers, such as CHOP [C/EBP (CCAAT/enhancer-binding protein)-homologous protein], ERdj4, GRP78 (glucose-regulated protein of 78 kDa) and XBP1 (X-box-binding protein 1). Thus CALHM1 might provide a relevant link between Ca(2+) homoeostasis disruption, ER stress and cell damage in the pathogenesis of neurodegenerative diseases.

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

    PubMed

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

    2013-01-01

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

  9. Electron spin resonance study of Er-concentration effect in GaAs;Er,O containing charge carriers

    SciTech Connect

    Elmasry, F.; Okubo, S.; Ohta, H.; Fujiwara, Y.

    2014-05-21

    Er-concentration effect in GaAs;Er,O containing charge carriers (n-type, high resistance, p-type) has been studied by X-band Electron spin resonance (ESR) at low temperature (4.7 K < T < 18 K). Observed A, B, and C types of ESR signals were identical to those observed previously in GaAs:Er,O without carrier. The local structure around Er-2O centers is not affected by carriers because similar angular dependence of g-values was observed in both cases (with/without carrier). For temperature dependence, linewidth and lineshape analysis suggested the existence of Er dimers with antiferromagnetic exchange interaction of about 7 K. Moreover, drastic decrease of ESR intensity for C signal in p-type sample was observed and it correlates with the decrease of photoluminescence (PL) intensity. Possible model for the Er-2O trap level in GaAs:Er,O is discussed from the ESR and PL experimental results.

  10. Absorption and photoluminescence properties of Er-doped and Er/Yb codoped soda-silicate laser glasses

    SciTech Connect

    Li, S.F.; Zhang, Q.Y.; Lee, Y.P.

    2004-11-01

    Er-doped and Er/Yb codoped soda-silicate laser glasses with various concentrations of Er and Yb were fabricated. The absorption and the photoluminescence (PL) spectra were measured and analyzed. For the Er- doped soda-slilicate glasses, the optimum Er concentration for the PL intensity at 1536 nm turns out to be 0.5 at. %, and the full width at half maximum (FWHM) of PL spectrum increases from 18 to 26 nm, with the increase of the concentration from 0.1 to 0.8 at. %. The PL intensity of Er/Yb codoped soda-silicate glasses with an Er concentration of 0.5 at. % is enhanced approximately by four times, and the optimum Yb concentration for the PL intensity at 1536 nm is analyzed to be 3.0 at. %. The PL spectrum becomes broader with increasing the Yb concentration, up to a FWHM of 80 nm at 6.0 at. %. Yb. The relation between the absorption and PL spectra, together with the mechanism of PL broadening, has also been addressed.

  11. Exciting transition metal doped dilute magnetic thin films: MgO:Er and ZnO:Er

    NASA Astrophysics Data System (ADS)

    Ćakıcı, T.; Sarıtaş, S.; Muǧlu, G. Merhan; Yıldırım, M.

    2017-02-01

    Erbium doped MgO and doped ZnO thin films have reasonably important properties applications in spintronic devices. These films were synthesized on glass substrates by Chemical Spray Pyrolysis (CSP) method. In the literature there has been almost no report on preparation of MgO:Er dilute magnetic thin films by means of CSP. Because doped thin films show different magnetic behaviors, depending upon the type of magnetic material ions, concentration of them, synthesis route and experimental conditions, synthesized MgO:Er and ZnO:Er films were compared to thin film properties. Optical analyses of the synthesized thin films were examined spectral absorption and transmittance measurements by UV-Vis double beam spectrophotometer technique. Structural analysis of the thin films was examined by using XRD, Raman Analysis, FE-SEM, EDX and AFM techniques. Also, magnetic properties of the MgO:Er and ZnO:Er films were investigated by vibrating sample magnetometer (VSM) which show that diamagnetic behavior of the MgO:Er thin film and ferromagnetic (FM) behavior of the ZnO:Er film were is formed.

  12. ER stress inhibitor attenuates hearing loss and hair cell death in Cdh23erl/erl mutant mice

    PubMed Central

    Hu, Juan; Li, Bo; Apisa, Luke; Yu, Heping; Entenman, Shami; Xu, Min; Stepanyan, Ruben; Guan, Bo-Jhih; Müller, Ulrich; Hatzoglou, Maria; Zheng, Qing Yin

    2016-01-01

    Hearing loss is one of the most common sensory impairments in humans. Mouse mutant models helped us to better understand the mechanisms of hearing loss. Recently, we have discovered that the erlong (erl) mutation of the cadherin23 (Cdh23) gene leads to hearing loss due to hair cell apoptosis. In this study, we aimed to reveal the molecular pathways upstream to apoptosis in hair cells to exploit more effective therapeutics than an anti-apoptosis strategy. Our results suggest that endoplasmic reticulum (ER) stress is the earliest molecular event leading to the apoptosis of hair cells and hearing loss in erl mice. We also report that the ER stress inhibitor, Salubrinal (Sal), could delay the progression of hearing loss and preserve hair cells. Our results provide evidence that therapies targeting signaling pathways in ER stress development prevent hair cell apoptosis at an early stage and lead to better outcomes than those targeting downstream factors, such as tip-link degeneration and apoptosis. PMID:27882946

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

    PubMed

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

    2017-03-27

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

  14. Depletion of the cereblon gene activates the unfolded protein response and protects cells from ER stress-induced cell death.

    PubMed

    Lee, Kwang Min; Yang, Seung-Joo; Park, Sojung; Choi, Yoo Duk; Shin, Hwa Kyoung; Pak, Jhang Ho; Park, Chul-Seung; Kim, Inki

    2015-02-27

    Previous studies showed that cereblon (CRBN) binds to various cellular target proteins, implying that CRBN regulates a wide range of cell responses. In this study, we found that deletion of the Crbn gene desensitized mouse embryonic fibroblast cells to various cell death-promoting stimuli, including endoplasmic reticulum stress inducers. Mechanistically, deletion of Crbn activates pathways involved in the unfolded protein response prior to ER stress induction. Loss of Crbn activated PKR-like ER kinase (PERK) with enhanced phosphorylation of eIF2α. Following ER stress induction, loss of Crbn delayed dephosphorylation of eIF2α, while reconstitution of Crbn reversed enhanced phosphorylation of PERK and eIF2α. Lastly, we found that activation of the PERK/eIF2α pathway following Crbn deletion is caused by activation of AMP-activated protein kinase (AMPK). We propose that CRBN plays a role in cellular stress signaling, including the unfolded protein response, by controlling the activity of AMPK.

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

    PubMed

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

    2016-02-28

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

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

    PubMed

    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.

  17. Superresolution Imaging Identifies That Conventional Trafficking Pathways Are Not Essential for Endoplasmic Reticulum to Outer Mitochondrial Membrane Protein Transport.

    PubMed

    Salka, Kyle; Bhuvanendran, Shivaprasad; Wilson, Kassandra; Bozidis, Petros; Mehta, Mansi; Rainey, Kristin; Sesaki, Hiromi; Patterson, George H; Jaiswal, Jyoti K; Colberg-Poley, Anamaris M

    2017-12-01

    Most nuclear-encoded mitochondrial proteins traffic from the cytosol to mitochondria. Some of these proteins localize at mitochondria-associated membranes (MAM), where mitochondria are closely apposed with the endoplasmic reticulum (ER). We have previously shown that the human cytomegalovirus signal-anchored protein known as viral mitochondria-localized inhibitor of apoptosis (vMIA) traffics from the ER to mitochondria and clusters at the outer mitochondrial membrane (OMM). Here, we have examined the host pathways by which vMIA traffics from the ER to mitochondria and clusters at the OMM. By disruption of phosphofurin acidic cluster sorting protein 2 (PACS-2), mitofusins (Mfn1/2), and dynamin related protein 1 (Drp1), we find these conventional pathways for ER to the mitochondria trafficking are dispensable for vMIA trafficking to OMM. Instead, mutations in vMIA that change its hydrophobicity alter its trafficking to mitochondria. Superresolution imaging showed that PACS-2- and Mfn-mediated membrane apposition or hydrophobic interactions alter vMIA's ability to organize in nanoscale clusters at the OMM. This shows that signal-anchored MAM proteins can make use of hydrophobic interactions independently of conventional ER-mitochondria pathways to traffic from the ER to mitochondria. Further, vMIA hydrophobic interactions and ER-mitochondria contacts facilitate proper organization of vMIA on the OMM.

  18. Opportunistic intruders: how viruses orchestrate ER functions to infect cells

    PubMed Central

    Cunningham, Corey Nathaniel; Tsai, Billy

    2017-01-01

    Viruses subvert the functions of their host cells to replicate and form new viral progeny. The endoplasmic reticulum (ER) has been identified as a central organelle that governs the intracellular interplay between viruses and hosts. In this Review, we analyse how viruses from vastly different families converge on this unique intracellular organelle during infection, co-opting some of the endogenous functions of the ER to promote distinct steps of the viral life cycle from entry and replication to assembly and egress. The ER can act as the common denominator during infection for diverse virus families, thereby providing a shared principle that underlies the apparent complexity of relationships between viruses and host cells. As a plethora of information illuminating the molecular and cellular basis of virus–ER interactions has become available, these insights may lead to the development of crucial therapeutic agents. PMID:27265768

  19. More Babies in Strollers, Cribs Winding Up in ER

    MedlinePlus

    ... in Strollers, Cribs Winding Up in ER: Study Concussions driving upswing, with only 1 percent of cases ... of the increase in injuries was related to concussions: The rate of concussion diagnoses more than doubled ...

  20. ERS-1 and Almaz ocean wave monitoring experiments

    NASA Technical Reports Server (NTRS)

    Beal, R. C.; Tilley, D. G.

    1992-01-01

    Preliminary results from two ocean wave monitoring experiments conducted in 1991 using the high-altitude ERS-1 synthetic aperture radar (SAR) and the low-altitude ex-USSR Almaz 1 SAR are presented. ERS-1 imagery of the Gulf Stream supports the idea that a future wide-swath scansar will be a valuable tool for monitoring large-scale ocean dynamics at high resolution. A direct comparison of ERS-1 and Almaz 1 ocean wave spectra shows major deficiencies in the ERS-1 high range-to-velocity ratio R/V sensor that are partially resolved with the lower-altitude Almaz platform. Optimum wave imaging from space will require both a low R/V and low off-nadir angle.

  1. Spectroscopic study of Er:Sm doped barium fluorotellurite glass.

    PubMed

    Bahadur, A; Dwivedi, Y; Rai, S B

    2010-09-15

    In this paper, we report the physical and spectroscopic properties of Er(3+), Sm(3+) and Er(3+):Sm(3+) ions codoped barium fluorotellurite (BFT) glasses. Different Stokes and anti-Stokes emissions were observed under 532 nm and 976 nm laser excitations. Energy transfer from Er(3+) ion to Sm(3+) ion was confirmed on the basis of luminescence intensity variation and decay curve analysis in both the cases. Under green (532 nm) excitation emission intensity of Sm(3+) ion bands improves whereas on NIR (976 nm) excitation new emission bands of Sm(3+) ions were observed in Er:Sm codoped samples. Ion interactions and the different energy transfer parameters were also calculated.

  2. ER-2 High Altitude Solar Cell Calibration Flights

    NASA Technical Reports Server (NTRS)

    Myers, Matthew G.; Piszczor, Michael F.

    2015-01-01

    The first flights of the ER-2 solar cell calibration demonstration were conducted during September-October of 2014. Three flights were performed that not only tested out the equipment and operational procedures, but also demonstrated the capability of this unique facility by conducting the first short-circuit measurements on a variety of test solar cells. Very preliminary results of these first flights were presented at the 2014 Space Photovoltaic Research and Technology (SPRAT) Conference in Cleveland, OH shortly following these first flights. At the 2015 Space Power Workshop, a more detailed description of these first ER-2 flights will be presented, along with the final flight data from some of the test cells that were flown and has now been reduced and corrected for ER-2 atmospheric flight conditions. Plans for ER-2 flights during the summer of 2015 will also be discussed.

  3. Balancing ER dynamics: shaping, bending, severing, and mending membranes

    PubMed Central

    Pendin, Diana; McNew, James A.; Daga, Andrea

    2011-01-01

    The endoplasmic reticulum is a multifunctional organelle composed of functionally and morphologically distinct domains. These include the relatively planar nuclear envelope and the peripheral ER, a network of sheet-like cisternae interconnected with tubules that spread throughout the cytoplasm. The ER is highly dynamic and the shape of its domains as well as their relative content are in constant flux. The multiple forces driving these morphological changes depend on the interaction between the ER and microtubules, membrane fusion and fission events and the action of proteins capable of actively shaping membranes. The interplay between these forces is ultimately responsible for the dynamic morphology of the ER, which in turn is crucial for properly executing the varied functions of this organelle. PMID:21641197

  4. A chloroplast pathway for the de novo biosynthesis of triacylglycerol in Chlamydomonas reinhardtii

    SciTech Connect

    Fan, J.; Xu, C.; Andre, C.

    2011-06-23

    Neutral lipid metabolism has been extensively studied in yeast, plants and mammals. In contrast, little information is available regarding the biochemical pathway, enzymes and regulatory factors involved in the biosynthesis of triacylglycerol (TAG) in microalgae. In the conventional TAG biosynthetic pathway widely accepted for yeast, plants and mammals, TAG is assembled in the endoplasmic reticulum (ER) from its immediate precursor diacylglycerol (DAG) made by ER-specific acyltransferases, and is deposited exclusively in lipid droplets in the cytosol. Here, we demonstrated that the unicellular microalga Chlamydomonas reinhardtii employs a distinct pathway that uses DAG derived almost exclusively from the chloroplast to produce TAG. This unique TAG biosynthesis pathway is largely dependent on de novo fatty acid synthesis, and the TAG formed in this pathway is stored in lipid droplets in both the chloroplast and the cytosol. These findings have wide implications for understanding TAG biosynthesis and storage and other areas of lipid metabolism in microalgae and other organisms.

  5. Measuring the Digital Divide with PingER

    SciTech Connect

    Cottrell, L.

    2003-10-01

    We introduce the PingER project/toolkit and show its relevance to monitoring sites in developing countries. We then show results from PingER that illustrate the extent of the Digital Divide in terms of Internet performance between developed and developing regions, which developing regions are catching up, keeping up, or falling behind and the magnitude of the differences in performance between developed regions and developing regions.

  6. Promoter and Cofactor Requirements for SERM-ER Activity

    DTIC Science & Technology

    2006-05-01

    Rett syndrome . Nat. Genet. 37, 31–40. keda, K., Sato, M., Tsutsumi, O., Tsuchiya, F., Tsuneizumi, M., Emi, ., Imoto, I., Inazawa, J., Muramatsu, M., and...already found a number of novel ER associated proteins that appear to be essential for ER-mediated transcription 14. SUBJECT TERMS 15. NUMBER OF...identify long distance cis-regulatory elements, which proved successful in two of the three assessed cases, including TFF-1 and NRIP-1. This for the first

  7. Selective, potent blockade of the IRE1 and ATF6 pathways by 4-phenylbutyric acid analogues

    PubMed Central

    Zhang, Hui; Nakajima, Shotaro; Kato, Hironori; Gu, Liubao; Yoshitomi, Tatsuya; Nagai, Kaoru; Shinmori, Hideyuki; Kokubo, Susumu; Kitamura, Masanori

    2013-01-01

    BACKGROUND AND PURPOSE 4-Phenylbutyric acid (4-PBA) is a chemical chaperone that eliminates the accumulation of unfolded proteins in the endoplasmic reticulum (ER). However, its chaperoning ability is often weak and unable to attenuate the unfolded protein response (UPR) in vitro or in vivo. To develop more potent chemical chaperones, we synthesized six analogues of 4-PBA and evaluated their pharmacological actions on the UPR. EXPERIMENTAL APPROACH NRK-52E cells were treated with ER stress inducers (tunicamycin or thapsigargin) in the presence of each of the 4-PBA analogues; the suppressive effects of these analogues on the UPR were assessed using selective indicators for individual UPR pathways. KEY RESULTS 2-POAA-OMe, 2-POAA-NO2 and 2-NOAA, but not others, suppressed the induction of ER stress markers GRP78 and CHOP. This suppressive effect was more potent than that of 4-PBA. Of the three major UPR branches, the IRE1 and ATF6 pathways were markedly blocked by these compounds, as indicated by suppression of XBP1 splicing, inhibition of UPRE and ERSE activation, and inhibition of JNK phosphorylation. Unexpectedly, however, these agents did not inhibit phosphorylation of PERK and eIF2α triggered by ER stress. These compounds dose-dependently inhibited the early activation of NF-κB in ER stress-exposed cells. 2-POAA-OMe and 2-POAA-NO2 also inhibited ER stress-induced phosphorylation of Akt. CONCLUSION AND IMPLICATIONS The 4-PBA analogues 2-POAA-OMe, 2-POAA-NO2 and 2-NOAA strongly inhibited activation of the IRE1 and ATF6 pathways and downstream pathogenic targets, including NF-κB and Akt, in ER stress-exposed cells. These compounds may be useful for therapeutic intervention in ER stress-related pathological conditions. PMID:23869584

  8. Oceanographic results from analysis of ERS-1 altimetry

    NASA Technical Reports Server (NTRS)

    Tapley, B. D.; Shum, C. K.; Chambers, D. P.; Peterson, G. E.; Ries, J. C.

    1994-01-01

    Large scale dynamic ocean topography and its variations were observed using ERS-1 radar altimeter measurements. The altimeter measurements analyzed are primarily from the ESA ocean product (OPR02) and from the Interim Geophysical Data Records (IGDR) generated by NOAA from the fast delivery (FD) data during the ERS-1 35 day repeat orbit phase. The precise orbits used for the dynamic topography solution are computed using dual satellite crossover measurements from ERS-1 and TOPEX (Topology Ocean Experiment)/Poseidon (T/P) as additional tracking data, and using improved models and constants which are consistent with T/P. Analysis of the ERS-1 dynamic topography solution indicates agreement with the T/P solution at the 5 cm root mean square level, with regional differences as large as 15 cm tide gauges at the 8 to 9 cm level. There are differences between the ERS-1 OPR02 and IGDR determined dynamic topography solutions on the order of 5 cm root mean square. Mesoscale oceanic variability time series obtained using collinear analysis of the ERS-1 altimeter data show good qualitative agreement when compared with the T/P results.

  9. Lockheed ER-2 #806 high altitude research aircraft in flight

    NASA Technical Reports Server (NTRS)

    1998-01-01

    ER-2 tail number 806, is one of two Airborne Science ER-2s used as science platforms by Dryden. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, the ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The aircraft is 63 feet long, with a wingspan of 104 feet. The top of the vertical tail is 16 feet above ground when the aircraft is on the bicycle-type landing gear. Cruising speeds are 410 knots, or 467 miles per hour, at altitude. A single General Electric F-118 turbofan engine rated at 17,000 pounds thrust powers the ER-2.

  10. Lockheed ER-2 high altitude research aircraft in flight

    NASA Technical Reports Server (NTRS)

    1997-01-01

    ER-2 tail number 706, is one of two Airborne Science ER-2s used as science platforms by Dryden. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, the ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The aircraft is 63 feet long, with a wingspan of 104 feet. The top of the vertical tail is 16 feet above ground when the aircraft is on the bicycle-type landing gear. Cruising speeds are 410 knots, or 467 miles per hour, at altitude. A single General Electric F-118 turbofan engine rated at 17,000 pounds thrust powers the ER-2.

  11. Lockheed ER-2 #806 high altitude research aircraft during landing

    NASA Technical Reports Server (NTRS)

    1998-01-01

    ER-2 tail number 806, is one of two Airborne Science ER-2s used as science platforms by Dryden. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, the ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The aircraft is 63 feet long, with a wingspan of 104 feet. The top of the vertical tail is 16 feet above ground when the aircraft is on the bicycle-type landing gear. Cruising speeds are 410 knots, or 467 miles per hour, at altitude. A single General Electric F-118 turbofan engine rated at 17,000 pounds thrust powers the ER-2.

  12. Lockheed ER-2 #809 high altitude research aircraft in flight

    NASA Technical Reports Server (NTRS)

    1999-01-01

    ER-2 tail number 809, is one of two Airborne Science ER-2s used as science platforms by Dryden. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, the ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The aircraft is 63 feet long, with a wingspan of 104 feet. The top of the vertical tail is 16 feet above ground when the aircraft is on the bicycle-type landing gear. Cruising speeds are 410 knots, or 467 miles per hour, at altitude. A single General Electric F118 turbofan engine rated at 17,000 pounds thrust powers the ER-2.

  13. Lockheed ER-2 #809 high altitude research aircraft in flight

    NASA Technical Reports Server (NTRS)

    1998-01-01

    ER-2 tail number 809, is one of two Airborne Science ER-2s used as science platforms by Dryden. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, the ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The aircraft is 63 feet long, with a wingspan of 104 feet. The top of the vertical tail is 16 feet above ground when the aircraft is on the bicycle-type landing gear. Cruising speeds are 410 knots, or 467 miles per hour, at altitude. A single General Electric F-118 turbofan engine rated at 17,000 pounds thrust powers the ER-2.

  14. Memantine ER/Donepezil: A Review in Alzheimer's Disease.

    PubMed

    Greig, Sarah L

    2015-11-01

    A once-daily, fixed-dose combination of memantine extended-release (ER)/donepezil 28/10 mg (Namzaric™) is available in the USA for patients with moderate to severe Alzheimer's disease (AD) on stable memantine and donepezil therapy. The fixed-dose formulation is bioequivalent to coadministration of the individual drugs. In a 24-week, phase III trial in patients with moderate to severe AD, addition of memantine ER 28 mg once daily to stable cholinesterase inhibitor (ChEI) therapy was more effective than add-on placebo on measures of cognition, global clinical status, dementia behaviour and semantic processing ability, although between-group differences on a measure of daily function did not significantly differ. In subgroup analyses in donepezil-treated patients, add-on memantine ER was more effective than add-on placebo on measures of cognition, dementia behaviour and semantic processing, although there were no significant between-group differences on measures of global clinical status and daily function. Memantine ER plus ChEI combination therapy was generally well tolerated in the phase III trial, with diarrhoea, dizziness and influenza occurring at least twice as often with add-on memantine ER as add-on placebo in donepezil-treated patients. Thus, memantine ER plus donepezil combination therapy is an effective and well tolerated treatment option for patients with moderate to severe AD. The fixed-dose combination is potentially more convenient than coadministration of the individual agents.

  15. A model for the generation and interconversion of ER morphologies

    PubMed Central

    Shemesh, Tom; Klemm, Robin W.; Romano, Fabian B.; Wang, Songyu; Vaughan, Joshua; Zhuang, Xiaowei; Tukachinsky, Hanna; Kozlov, Michael M.; Rapoport, Tom A.

    2014-01-01

    The peripheral endoplasmic reticulum (ER) forms different morphologies composed of tubules and sheets. Proteins such as the reticulons shape the ER by stabilizing the high membrane curvature in cross-sections of tubules and sheet edges. Here, we show that membrane curvature along the edge lines is also critical for ER shaping. We describe a theoretical model that explains virtually all observed ER morphologies. The model is based on two types of curvature-stabilizing proteins that generate either straight or negatively curved edge lines (R- and S-type proteins). Dependent on the concentrations of R- and S-type proteins, membrane morphologies can be generated that consist of tubules, sheets, sheet fenestrations, and sheet stacks with helicoidal connections. We propose that reticulons 4a/b are representatives of R-type proteins that favor tubules and outer edges of sheets. Lunapark is an example of S-type proteins that promote junctions between tubules and sheets. In a tubular ER network, lunapark stabilizes three-way junctions, i.e., small triangular sheets with concave edges. The model agrees with experimental observations and explains how curvature-stabilizing proteins determine ER morphology. PMID:25404289

  16. Laser performance of in-band pumped Er : LiYF4 and Er : LiLuF4 crystals

    NASA Astrophysics Data System (ADS)

    Gorbachenya, K. N.; Kurilchik, S. V.; Kisel, V. E.; Yasukevich, A. S.; Kuleshov, N. V.; Nizamutdinov, A. S.; Korableva, S. L.; Semashko, V. V.

    2016-02-01

    Spectroscopic properties of Er : LiLuF4 and Er : LiYF4 crystals in the spectral region near 1.5 μm and the lasing characteristics of these crystals under in-band pumping at a wavelength of 1522 nm are studied. With the Er : LiLuF4 crystal, the maximum slope efficiency with respect to the absorbed pump power was 44% at a wavelength of 1609 nm. Continuous-wave operation of an inband pumped Er : LiYF4 laser is obtained for the first time. The output power at a wavelength of 1606 nm was 58 mW with a slope efficiency of 21%.

  17. Leptin signalling pathways in hypothalamic neurons.

    PubMed

    Kwon, Obin; Kim, Ki Woo; Kim, Min-Seon

    2016-04-01

    Leptin is the most critical hormone in the homeostatic regulation of energy balance among those so far discovered. Leptin primarily acts on the neurons of the mediobasal part of hypothalamus to regulate food intake, thermogenesis, and the blood glucose level. In the hypothalamic neurons, leptin binding to the long form leptin receptors on the plasma membrane initiates multiple signaling cascades. The signaling pathways known to mediate the actions of leptin include JAK-STAT signaling, PI3K-Akt-FoxO1 signaling, SHP2-ERK signaling, AMPK signaling, and mTOR-S6K signaling. Recent evidence suggests that leptin signaling in hypothalamic neurons is also linked to primary cilia function. On the other hand, signaling molecules/pathways mitigating leptin actions in hypothalamic neurons have been extensively investigated in an effort to treat leptin resistance observed in obesity. These include SOCS3, tyrosine phosphatase PTP1B, and inflammatory signaling pathways such as IKK-NFκB and JNK signaling, and ER stress-mitochondrial signaling. In this review, we discuss leptin signaling pathways in the hypothalamus, with a particular focus on the most recently discovered pathways.

  18. TorsinA rescues ER-associated stress and locomotive defects in C. elegans models of ALS.

    PubMed

    Thompson, Michelle L; Chen, Pan; Yan, Xiaohui; Kim, Hanna; Borom, Akeem R; Roberts, Nathan B; Caldwell, Kim A; Caldwell, Guy A

    2014-02-01

    Molecular mechanisms underlying neurodegenerative diseases converge at the interface of pathways impacting cellular stress, protein homeostasis and aging. Targeting the intrinsic capacities of neuroprotective proteins to restore neuronal function and/or attenuate degeneration represents a potential means toward therapeutic intervention. The product of the human DYT1 gene, torsinA, is a member of the functionally diverse AAA+ family of proteins and exhibits robust molecular-chaperone-like activity, both in vitro and in vivo. Although mutations in DYT1 are associated with a rare form of heritable generalized dystonia, the native function of torsinA seems to be cytoprotective in maintaining the cellular threshold to endoplasmic reticulum (ER) stress. Here we explore the potential for torsinA to serve as a buffer to attenuate the cellular consequences of misfolded-protein stress as it pertains to the neurodegenerative disease amyotrophic lateral sclerosis (ALS). The selective vulnerability of motor neurons to degeneration in ALS mouse models harboring mutations in superoxide dismutase (SOD1) has been found to correlate with regional-specific ER stress in brains. Using Caenorhabditis elegans as a system to model ER stress, we generated transgenic nematodes overexpressing either wild-type or mutant human SOD1 to evaluate their relative impact on ER stress induction in vivo. These studies revealed a mutant-SOD1-specific increase in ER stress that was further exacerbated by changes in temperature, all of which was robustly attenuated by co-expression of torsinA. Moreover, through complementary behavioral analysis, torsinA was able to restore normal neuronal function in mutant G85R SOD1 animals. Furthermore, torsinA targeted mutant SOD1 for degradation via the proteasome, representing mechanistic insight on the activity that torsinA has on aggregate-prone proteins. These results expand our understanding of proteostatic mechanisms influencing neuronal dysfunction in ALS

  19. TorsinA rescues ER-associated stress and locomotive defects in C. elegans models of ALS

    PubMed Central

    Thompson, Michelle L.; Chen, Pan; Yan, Xiaohui; Kim, Hanna; Borom, Akeem R.; Roberts, Nathan B.; Caldwell, Kim A.; Caldwell, Guy A.

    2014-01-01

    ABSTRACT Molecular mechanisms underlying neurodegenerative diseases converge at the interface of pathways impacting cellular stress, protein homeostasis and aging. Targeting the intrinsic capacities of neuroprotective proteins to restore neuronal function and/or attenuate degeneration represents a potential means toward therapeutic intervention. The product of the human DYT1 gene, torsinA, is a member of the functionally diverse AAA+ family of proteins and exhibits robust molecular-chaperone-like activity, both in vitro and in vivo. Although mutations in DYT1 are associated with a rare form of heritable generalized dystonia, the native function of torsinA seems to be cytoprotective in maintaining the cellular threshold to endoplasmic reticulum (ER) stress. Here we explore the potential for torsinA to serve as a buffer to attenuate the cellular consequences of misfolded-protein stress as it pertains to the neurodegenerative disease amyotrophic lateral sclerosis (ALS). The selective vulnerability of motor neurons to degeneration in ALS mouse models harboring mutations in superoxide dismutase (SOD1) has been found to correlate with regional-specific ER stress in brains. Using Caenorhabditis elegans as a system to model ER stress, we generated transgenic nematodes overexpressing either wild-type or mutant human SOD1 to evaluate their relative impact on ER stress induction in vivo. These studies revealed a mutant-SOD1-specific increase in ER stress that was further exacerbated by changes in temperature, all of which was robustly attenuated by co-expression of torsinA. Moreover, through complementary behavioral analysis, torsinA was able to restore normal neuronal function in mutant G85R SOD1 animals. Furthermore, torsinA targeted mutant SOD1 for degradation via the proteasome, representing mechanistic insight on the activity that torsinA has on aggregate-prone proteins. These results expand our understanding of proteostatic mechanisms influencing neuronal dysfunction in

  20. NHERF1, a novel GPER associated protein, increases stability and activation of GPER in ER-positive breast cancer

    PubMed Central

    Xiong, Ying; Wang, Yan; Zheng, Junfang; Zhao, Yuan; Tao, Tao; Wang, Qiqi; Liu, Hua; Wang, Songlin; Jiang, Wen G.; He, Junqi

    2016-01-01

    G protein-coupled estrogen receptor (GPER) plays an important role in mediating the effects of estradiol. High levels of GPER have been implicated to associate with the malignant progress of invasive breast cancer (IBC). However, the mechanisms by which GPER protein levels were regulated remain unclear. In this study, PDZ protein Na+/H+ exchanger regulatory factor (NHERF1) was found to interact with GPER in breast cancer cells. This interaction was mediated by the PDZ2 domain of NHERF1 and the carboxyl terminal PDZ binding motif of GPER. NHERF1 was demonstrated to facilitate GPER expression at post-transcriptional level and improve GPER protein stability by inhibiting the receptor degradation via ubiquitin-proteasome pathway in a GPER/NHERF1 interaction-dependent manner. In addition, GPER protein levels are positively associated with NHERF1 protein levels in a panel of estrogen receptor (ER)-positive breast cancer cells. Furthermore, analysis of clinical IBC data from The Cancer Genome Atlas (TCGA) showed no significant difference in GPER mRNA levels between ER-positive IBC and normal breast tissues. However, gene set enrichment analysis (GSEA) showed that GPER signaling is ultra-activated in ER-positive IBC when compared with normal and its activation is positively associated with NHERF1 mRNA levels. Taken together, our findings identify NHERF1 as a new binding partner for GPER and its overexpression promotes protein stability and activation of GPER in ER-positive IBC. Our data indicate that regulation of GPER stability by NHERF1 may contribute to GPER-mediated carcinogenesis in ER-positive IBC. PMID:27448983

  1. Judd-Ofelt analysis of the Er3+ (4f11) absorption intensities in Er3+-doped garnets

    NASA Astrophysics Data System (ADS)

    Sardar, Dhiraj K.; Bradley, William M.; Perez, John J.; Gruber, John B.; Zandi, Bahram; Hutchinson, J. Andrew; Trussell, C. Ward; Kokta, Milan R.

    2003-03-01

    Spectroscopic and laser properties of three different Er3+-doped garnet systems are characterized by employing the Judd-Ofelt (JO) analysis. The three garnet hosts are Y3Al5O12 (YAG), Y3Sc2Ga3O12 (YSGG), and Gd3Ga5O12 (GGG). The JO model has been applied to the room temperature absorption intensities of Er3+ (4f11) transitions to establish the so-called JO intensity parameters: Ω2, Ω4, and Ω6 in the three garnet hosts. The intensity parameters are used to determine the radiative decay rates (emission probabilities of transitions) and branching ratios of the Er3+ transitions from the excited state J manifolds to the lower-lying J' manifolds. The predicted decay rates and branching ratios of these Er3+ transitions in YAG, YSGG, and GGG hosts are compared. From the radiative decay rates, the radiative lifetimes of the Er3+ excited states are determined in the three garnets and are also compared. We also report the spectroscopic quality factors, Ω4/Ω6, obtained for the three garnets. The quantum efficiencies of the 4I13/2→4I15/2 Er3+ transition in YAG, YSGG, and GGG are determined to be ˜79%, 82%, and 85%, respectively.

  2. An ER protein functionally couples neutral lipid metabolism on lipid droplets to membrane lipid synthesis in the ER.

    PubMed

    Markgraf, Daniel F; Klemm, Robin W; Junker, Mirco; Hannibal-Bach, Hans K; Ejsing, Christer S; Rapoport, Tom A

    2014-01-16

    Eukaryotic cells store neutral lipids such as triacylglycerol (TAG) in lipid droplets (LDs). Here, we have addressed how LDs are functionally linked to the endoplasmic reticulum (ER). We show that, in S. cerevisiae, LD growth is sustained by LD-localized enzymes. When LDs grow in early stationary phase, the diacylglycerol acyl-transferase Dga1p moves from the ER to LDs and is responsible for all TAG synthesis from diacylglycerol (DAG). During LD breakdown in early exponential phase, an ER membrane protein (Ice2p) facilitates TAG utilization for membrane-lipid synthesis. Ice2p has a cytosolic domain with affinity for LDs and is required for the efficient utilization of LD-derived DAG in the ER. Ice2p breaks a futile cycle on LDs between TAG degradation and synthesis, promoting the rapid relocalization of Dga1p to the ER. Our results show that Ice2p functionally links LDs with the ER and explain how cells switch neutral lipid metabolism from storage to consumption.

  3. mTORC1 inhibitor rapamycin and ER stressor tunicamycin induce differential patterns of ER-mitochondria coupling

    PubMed Central

    Bravo-Sagua, Roberto; López-Crisosto, Camila; Parra, Valentina; Rodriguez-Peña, Marcelo; Rothermel, Beverly A.; Quest, Andrew F.G.; Lavandero, Sergio

    2016-01-01

    Efficient mitochondrial Ca2+ uptake takes place at contact points between the ER and mitochondria, and represents a key regulator of many cell functions. In a previous study with HeLa cells, we showed that ER-to-mitochondria Ca2+ transfer increases during the early phase of ER stress induced by tunicamycin as an adaptive response to stimulate mitochondrial bioenergetics. It remains unknown whether other types of stress signals trigger similar responses. Here we observed that rapamycin, which inhibits the nutrient-sensing complex mTORC1, increased ER-mitochondria coupling in HeLa cells to a similar extent as did tunicamycin. Interestingly, although global responses to both stressors were comparable, there were notable differences in the spatial distribution of such changes. While tunicamycin increased organelle proximity primarily in the perinuclear region, rapamycin increased organelle contacts throughout the entire cell. These differences were paralleled by dissimilar alterations in the distribution of regulatory proteins of the ER-mitochondria interface, heterogeneities in mitochondrial Ca2+ uptake, and the formation of domains within the mitochondrial network with varying mitochondrial transmembrane potential. Collectively, these data suggest that while increasing ER-mitochondria coupling appears to represent a general response to cell stress, the intracellular distribution of the associated responses needs to be tailored to meet specific cellular requirements. PMID:27808250

  4. Iminosugars Inhibit Dengue Virus Production via Inhibition of ER Alpha-Glucosidases—Not Glycolipid Processing Enzymes

    PubMed Central

    Sayce, Andrew C.; Alonzi, Dominic S.; Killingbeck, Sarah S.; Tyrrell, Beatrice E.; Hill, Michelle L.; Caputo, Alessandro T.; Iwaki, Ren; Kinami, Kyoko; Ide, Daisuke; Kiappes, J. L.; Beatty, P. Robert; Kato, Atsushi; Harris, Eva; Dwek, Raymond A.; Miller, Joanna L.; Zitzmann, Nicole

    2016-01-01

    It has long been thought that iminosugar antiviral activity is a function of inhibition of endoplasmic reticulum-resident α-glucosidases, and on this basis, many iminosugars have been investigated as therapeutic agents for treatment of infection by a diverse spectrum of viruses, including dengue virus (DENV). However, iminosugars are glycomimetics possessing a nitrogen atom in place of the endocyclic oxygen atom, and the ubiquity of glycans in host metabolism suggests that multiple pathways can be targeted via iminosugar treatment. Successful treatment of patients with glycolipid processing defects using iminosugars highlights the clinical exploitation of iminosugar inhibition of enzymes other than ER α-glucosidases. Evidence correlating antiviral activity with successful inhibition of ER glucosidases together with the exclusion of alternative mechanisms of action of iminosugars in the context of DENV infection is limited. Celgosivir, a bicyclic iminosugar evaluated in phase Ib clinical trials as a therapeutic for the treatment of DENV infection, was confirmed to be antiviral in a lethal mouse model of antibody-enhanced DENV infection. In this study we provide the first evidence of the antiviral activity of celgosivir in primary human macrophages in vitro, in which it inhibits DENV secretion with an EC50 of 5 μM. We further demonstrate that monocyclic glucose-mimicking iminosugars inhibit isolated glycoprotein and glycolipid processing enzymes and that this inhibition also occurs in primary cells treated with these drugs. By comparison to bicyclic glucose-mimicking iminosugars which inhibit glycoprotein processing but do not inhibit glycolipid processing and galactose-mimicking iminosugars which do not inhibit glycoprotein processing but do inhibit glycolipid processing, we demonstrate that inhibition of endoplasmic reticulum-resident α-glucosidases, not glycolipid processing, is responsible for iminosugar antiviral activity against DENV. Our data suggest that

  5. Structural Analysis of the QCM Aboard the ER-2

    NASA Technical Reports Server (NTRS)

    Jones, Phyllis D.; Bainum, Peter M.; Xing, Guangqian

    1997-01-01

    As a result of recent supersonic transport (SST) studies on the effect they may have on the atmosphere, several experiments have been proposed to capture and evaluate samples of the stratosphere where SST's travel. One means to achieve this is to utilize the quartz crystal microbalance (QCM) installed aboard the ER-2, formerly the U-2 reconnaissance aircraft. The QCM is a cascade impactor designed to perform in-situ, real-time measurements of aerosols and chemical vapors at an altitude of 60,000 - 70,000 feet. The ER-2 is primarily used by NASA for Earth resources to test new sensor systems before they are placed aboard satellites. One of the main reasons the ER-2 is used for this flight experiment is its capability to fly approximately twelve miles above sea level (can reach an altitude of 78,000 feet). Because the ER-2 operates at such a high altitude, it is of special interest to scientists interested in space exploration or supersonic aircraft. Some of the experiments are designed to extract data from the atmosphere around the ER-2. For the current flight experiment, the QCM is housed in a frame that is connected to an outer pod that is attached to the fuselage of the ER-2. Due to the location of the QCM within the housing frame and the location of the pod on the ER-2, the pod and its contents are subject to structural loads. In addition to structural loads, structural vibrations are also of importance because the QCM is a frequency induced instrument. Therefore, a structural analysis of the instrument within the frame is imperative to determine if resonance and/or undesirable deformations occur.

  6. The widow(er)'s limit provision of Social Security.

    PubMed

    Weaver, D A

    Widow benefits have been a part of the Social Security program since the 1939 amendments to the Social Security Act (widower benefits were added later). For many years, the Social Security law called for paying a widow(er) a fraction of the deceased worker's primary insurance amount (PIA). However, the worker--while alive--may have received the full PIA as his or her retirement benefit. Over time, arguments were made that a widow(er) should be treated as generously as his or her spouse was. The 1972 amendments to the Social Security Act allowed for a widow(er) to receive a full PIA, subject to actuarial reductions if the widow(er) benefit was claimed before the normal retirement age (NRA) and subject to a new provision of the law commonly referred to as the widow(er)'s limit. Generally, the widow(er)'s limit specifies that if a worker received reduced retirement benefits (because the worker claimed benefits before the NRA), then the worker's widow(er) cannot receive a monthly benefit equal to the full PIA. Rather, the widow(er)'s benefit is generally limited to the amount the worker would receive if he or she was still alive. The limit provision appears to be motivated by the overall intent of the 1972 Congress to pay a benefit to a widow(er) that was comparable with what the worker received. A number of changes to the limit provision have been discussed. This article looks at the following options: Abolishing the limit, Raising the limit by requiring that it never be set below the average PIA among all retired-worker beneficiaries. Adjusting the limit for some widow(er)s--that is, only persons who are widowed before the NRA (the ARLA option), Making a simpler adjustment to the limit by abolishing it for persons who are widowed before age 62 (the SARLA option), and A proposal by Robert J. Myers that would make modest adjustments to the limit for cases in which the worker died before the NRA. The most fundamental change--abolishing the limit--would increase benefits

  7. † THE GROUP VIA CALCIUM-INDEPENDENT PHOSPHOLIPASE A2 (iPLA2β)1 PARTICIPATES IN ER STRESS-INDUCED INS-1 INSULINOMA CELL APOPTOSIS BY PROMOTING CERAMIDE GENERATION VIA HYDROLYSIS OF SPHINGOMYELINS BY NEUTRAL SPHINGOMYELINASE

    PubMed Central

    Lei, Xiao-Yong; Zhang, Sheng; Bohrer, Alan; Bao, Shunzhong; Song, Haowei; Ramanadham, Sasanka

    2008-01-01

    ceramide generation or apoptosis in either V or OE INS-1 cells. These findings indicate that iPLA2β activation participates in ER stress-induced INS-1 cell apoptosis by promoting ceramide generation via NSMase-catalyzed hydrolysis of sphingomyelins, raising the possibility that this pathway contributes to β-cell apoptosis due to ER stress. PMID:17685585

  8. Effects of Y3+/Er3+ ratio on the 2.7 μm emission of Er3+ ions in oxyfluoride glass-ceramics

    NASA Astrophysics Data System (ADS)

    Zhao, Zhiyong; Liu, Chao; Xia, Mengling; Wang, Jing; Han, Jianjun; Xie, Jun; Zhao, Xiujian

    2016-04-01

    Y3+/Er3+ ions co-doped oxyfluoride glass-ceramics were investigated to realize efficient 2.7 μm emission. Incorporation of Er3+ ions into the fluoride nanocrystals was confirmed by the X-ray diffraction patterns, absorption spectra, emission spectra and Judd-Ofelt analysis. With an increase in the Y3+/Er3+ ratio, radiative lifetime, quantum efficiency and emission cross section of the 2.7 μm emission from Er3+ ions were greatly improved, due to the reduced effective concentration of Er3+ ions and suppressed cross relaxation processes among Er3+ ions in the fluoride nanocrystals. Compared to other Er3+-doped glasses, Y3+/Er3+ co-doped oxyfluoride glass-ceramics showed a promising potential for gain medium.

  9. Lithium induces ER stress and N-glycan modification in galactose-grown Jurkat cells.

    PubMed

    Nagy, Tamás; Frank, Dorottya; Kátai, Emese; Yahiro, Rikki K K; Poór, Viktor S; Montskó, Gergely; Zrínyi, Zita; Kovács, Gábor L; Miseta, Attila

    2013-01-01

    We previously reported that lithium had a significant impact on Ca(2+) regulation and induced unfolded protein response (UPR) in yeast cells grown on galactose due to inhibition of phosphoglucomutase (PGM), however the exact mechanism has not been established yet. In this study, we analysed lithium's effect in galactose-fed cells to clarify whether these ER-related changes are the result of a relative hypoglycemic state. Furthermore, we investigated whether the alterations in galactose metabolism impact protein post-translational modifications. Thus, Jurkat cells were incubated in glucose or galactose containing media with or without lithium treatment. We found that galactose-fed and lithium treated cells showed better survivability than fasting cells. We also found higher UDP-Hexose and glycogen levels in these cells compared to fasting cells. On the other hand, the UPR (X-box binding protein 1 mRNA levels) of galactose-fed and lithium treated cells was even greater than in fasting cells. We also found increased amount of proteins that contained N-linked N-acetyl-glucosamine, similar to what was reported in fasting cells by a recent study. Our results demonstrate that lithium treatment of galactose-fed cells can induce stress responses similar to hypoglycemia, however cell survival is still secured by alternative pathways. We propose that clarifying this process might be an important addition toward the better understanding of the molecular mechanisms that regulate ER-associated stress response.

  10. COPA mutations impair ER-Golgi transport causing hereditary autoimmune-mediated lung disease and arthritis

    PubMed Central

    Watkin, Levi B.; Jessen, Birthe; Wiszniewski, Wojciech; Vece, Timothy; Jan, Max; Sha, Youbao; Thamsen, Maike; Santos-Cortez, Regie L. P.; Lee, Kwanghyuk; Gambin, Tomasz; Forbes, Lisa; Law, Christopher S.; Stray-Petersen, Asbjørg; Cheng, Mickie H.; Mace, Emily M.; Anderson, Mark S.; Liu, Dongfang; Tang, Ling Fung; Nicholas, Sarah K.; Nahmod, Karen; Makedonas, George; Canter, Debra; Kwok, Pui-Yan; Hicks, John; Jones, Kirk D.; Penney, Samantha; Jhangiani, Shalini N.; Rosenblum, Michael D.; Dell, Sharon D.; Waterfield, Michael R.; Papa, Feroz R.; Muzny, Donna M.; Zaitlen, Noah; Leal, Suzanne M.; Gonzaga-Jauregui, Claudia; Boerwinkle, Eric; Eissa, N. Tony; Gibbs, Richard A.; Lupski, James R.; Orange, Jordan S.; Shum, Anthony K.

    2015-01-01

    Advances in genomics have allowed unbiased genetic studies of human disease with unexpected insights into the molecular mechanisms of cellular immunity and autoimmunity1. We performed whole exome sequencing (WES) and targeted sequencing in patients with an apparent Mendelian syndrome of autoimmune disease characterized by high-titer autoantibodies, inflammatory arthritis and interstitial lung disease (ILD). In five families, we identified four unique deleterious variants in the Coatomer subunit alpha (COPA) gene all located within the same functional domain. We hypothesized that mutant COPA leads to a defect in intracellular transport mediated by coat protein complex I (COPI)2–4. We show that COPA variants impair binding of proteins targeted for retrograde Golgi to ER transport and demonstrate that expression of mutant COPA leads to ER stress and the upregulation of Th17 priming cytokines. Consistent with this pattern of cytokine expression, patients demonstrated a significant skewing of CD4+ T cells toward a T helper 17 (Th17) phenotype, an effector T cell population implicated in autoimmunity5,6. Our findings uncover an unexpected molecular link between a vesicular transport protein and a syndrome of autoimmunity manifested by lung and joint disease. These findings provide a unique opportunity to understand how alterations in cellular homeostasis caused by a defect in the intracellular trafficking pathway leads to the generation of human autoimmune disease. PMID:25894502

  11. Aberrant substrate engagement of the ER translocon triggers degradation by the Hrd1 ubiquitin ligase

    PubMed Central

    Rubenstein, Eric M.; Kreft, Stefan G.; Greenblatt, Wesley; Swanson, Robert

    2012-01-01

    Little is known about quality control of proteins that aberrantly or persistently engage the endoplasmic reticulum (ER)-localized translocon en route to membrane localization or the secretory pathway. Hrd1 and Doa10, the primary ubiquitin ligases that function in ER-associated degradation (ERAD) in yeast, target distinct subsets of misfolded or otherwise abnormal proteins based primarily on degradation signal (degron) location. We report the surprising observation that fusing Deg1, a cytoplasmic degron normally recognized by Doa10, to the Sec62 membrane protein rendered the protein a Hrd1 substrate. Hrd1-dependent degradation occurred when Deg1-Sec62 aberrantly engaged the Sec61 translocon channel and underwent topological rearrangement. Mutations that prevent translocon engagement caused a reversion to Doa10-dependent degradation. Similarly, a variant of apolipoprotein B, a protein known to be cotranslocationally targeted for proteasomal degradation, was also a Hrd1 substrate. Hrd1 therefore likely plays a general role in targeting proteins that persistently associate with and potentially obstruct the translocon. PMID:22689655

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

    PubMed Central

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

    2015-01-01

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

  13. Structural Mechanism of ER Retrieval of MHC Class I by Cowpox

    PubMed Central

    McCoy, William H.; Wang, Xiaoli; Yokoyama, Wayne M.; Hansen, Ted H.; Fremont, Daved H.

    2012-01-01

    One of the hallmarks of viral immune evasion is the capacity to disrupt major histocompatibility complex class I (MHCI) antigen presentation to evade T-cell detection. Cowpox virus encoded protein CPXV203 blocks MHCI surface expression by exploiting the KDEL-receptor recycling pathway, and here we show that CPXV203 directly binds a wide array of fully assembled MHCI proteins, both classical and non-classical. Further, the stability of CPXV203/MHCI complexes is highly pH dependent, with dramatically increased affinities at the lower pH of the Golgi relative to the endoplasmic reticulum (ER). Crystallographic studies reveal that CPXV203 adopts a beta-sandwich fold similar to poxvirus chemokine binding proteins, and binds the same highly conserved MHCI determinants located under the peptide-binding platform that tapasin, CD8, and natural killer (NK)-receptors engage. Mutagenesis of the CPXV203/MHCI interface identified the importance of two CPXV203 His residues that confer low pH stabilization of the complex and are critical to ER retrieval of MHCI. These studies clarify mechanistically how CPXV203 coordinates with other cowpox proteins to thwart antigen presentation. PMID:23209377

  14. Attenuation of PKR-like ER Kinase (PERK) Signaling Selectively Controls Endoplasmic Reticulum Stress-induced Inflammation Without Compromising Immunological Responses.

    PubMed

    Guthrie, Lauren N; Abiraman, Kavitha; Plyler, Emily S; Sprenkle, Neil T; Gibson, Sara A; McFarland, Braden C; Rajbhandari, Rajani; Rowse, Amber L; Benveniste, Etty N; Meares, Gordon P

    2016-07-22

    Inflammation and endoplasmic reticulum (ER) stress are associated with many neurological diseases. ER stress is brought on by the accumulation of misfolded proteins in the ER, which leads to activation of the unfolded protein response (UPR), a conserved pathway that transmits signals to restore homeostasis or eliminate the irreparably damaged cell. We provide evidence that inhibition or genetic haploinsufficiency of protein kinase R-like endoplasmic reticulum kinase (PERK) can selectively control inflammation brought on by ER stress without impinging on UPR-dependent survival and adaptive responses or normal immune responses. Using astrocytes lacking one or both alleles of PERK or the PERK inhibitor GSK2606414, we demonstrate that PERK haploinsufficiency or partial inhibition led to reduced ER stress-induced inflammation (IL-6, CCL2, and CCL20 expression) without compromising prosurvival responses. In contrast, complete loss of PERK blocked canonical PERK-dependent UPR genes and promoted apoptosis. Reversal of eIF2α-mediated translational repression using ISRIB potently suppressed PERK-dependent inflammatory gene expression, indicating that the selective modulation of inflammatory gene expression by PERK inhibition may be linked to attenuation of eIF2α phosphorylation and reveals a previously unknown link between translational repression and transcription of inflammatory genes. Additionally, ER-stressed astrocytes can drive an inflammatory M1-like phenotype in microglia, and this can be attenuated with inhibition of PERK. Importantly, targeting PERK neither disrupted normal cytokine signaling in astrocytes or microglia nor impaired macrophage phagocytosis or T cell polarization. Collectively, this work suggests that targeting PERK may provide a means for selective immunoregulation in the context of ER stress without disrupting normal immune function.

  15. Ubiquitin fold modifier 1 (UFM1) and its target UFBP1 protect pancreatic beta cells from ER stress-induced apoptosis.

    PubMed

    Lemaire, Katleen; Moura, Rodrigo F; Granvik, Mikaela; Igoillo-Esteve, Mariana; Hohmeier, Hans E; Hendrickx, Nico; Newgard, Christopher B; Waelkens, Etienne; Cnop, Miriam; Schuit, Frans

    2011-04-06

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

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

    PubMed Central

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

    2011-01-01

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

  17. The comER Gene Plays an Important Role in Biofilm Formation and Sporulation in both Bacillus subtilis and Bacillus cereus.

    PubMed

    Yan, Fang; Yu, Yiyang; Wang, Luyao; Luo, Yuming; Guo, Jian-Hua; Chai, Yunrong

    2016-01-01

    Bacteria adopt alternative cell fates during development. In Bacillus subtilis, the transition from planktonic growth to biofilm formation and sporulation is controlled by a complex regulatory circuit, in which the most important event is activation of Spo0A, a transcription factor and a master regulator for genes involved in both biofilm formation and sporulation. In B. cereus, the regulatory pathway controlling biofilm formation and cell differentiation is much less clear. In this study, we show that a novel gene, comER, plays a significant role in biofilm formation as well as sporulation in both B. subtilis and B. cereus. Mutations in the comER gene result in defects in biofilm formation and a delay in spore formation in the two Bacillus species. Our evidence supports the idea that comER may be part of the regulatory circuit that controls Spo0A activation. comER likely acts upstream of sda, a gene encoding a small checkpoint protein for both sporulation and biofilm formation, by blocking the phosphor-relay and thereby Spo0A activation. In summary, our studies outlined a conserved, positive role for comER, a gene whose function was previously uncharacterized, in the regulation of biofilm formation and sporulation in the two Bacillus species.

  18. The comER Gene Plays an Important Role in Biofilm Formation and Sporulation in both Bacillus subtilis and Bacillus cereus

    PubMed Central

    Yan, Fang; Yu, Yiyang; Wang, Luyao; Luo, Yuming; Guo, Jian-hua; Chai, Yunrong

    2016-01-01

    Bacteria adopt alternative cell fates during development. In Bacillus subtilis, the transition from planktonic growth to biofilm formation and sporulation is controlled by a complex regulatory circuit, in which the most important event is activation of Spo0A, a transcription factor and a master regulator for genes involved in both biofilm formation and sporulation. In B. cereus, the regulatory pathway controlling biofilm formation and cell differentiation is much less clear. In this study, we show that a novel gene, comER, plays a significant role in biofilm formation as well as sporulation in both B. subtilis and B. cereus. Mutations in the comER gene result in defects in biofilm formation and a delay in spore formation in the two Bacillus species. Our evidence supports the idea that comER may be part of the regulatory circuit that controls Spo0A activation. comER likely acts upstream of sda, a gene encoding a small checkpoint protein for both sporulation and biofilm formation, by blocking the phosphor-relay and thereby Spo0A activation. In summary, our studies outlined a conserved, positive role for comER, a gene whose function was previously uncharacterized, in the regulation of biofilm formation and sporulation in the two Bacillus species. PMID:27446060

  19. The ER/PM microdomain, PI(4,5)P2 and the regulation of STIM1-Orai1 channel function

    PubMed Central

    Cao, Xu; Choi, Seok; Maléth, Jozsef J.; Park, Seonghee; Ahuja, Malini; Muallem, Shmuel

    2015-01-01

    All forms of cell signaling occur in discreet cellular microdomains in which the ER is the main participant and include microdomains formed by the ER with lysosomes, endosomes, the nucleus, mitochondria and the plasma membrane. In the microdomains the two opposing organelles transfer and exchange constituents including lipids and ions. As is the case for other forms of signaling pathways, many components of the receptor-evoked Ca2+ signal are clustered at the ER/PM microdomain, including the Orai1-STIM1 complex. This review discusses recent advances in understanding the molecular components that tether the ER and plasma membrane to form the ER/PM microdomains in which PI(4,5)P2 is enriched, and how dynamic targeting of the Orai1-STIM1 complex to PI(4,5)P2-poor and PI(4,5)P2-rich microdomains controls the activity of Orai1 and its regulation by Ca2+ that is mediated by SARAF. PMID:25843208

  20. Yet1p-Yet3p interacts with Scs2p-Opi1p to regulate ER localization of the Opi1p repressor.

    PubMed

    Wilson, Joshua D; Thompson, Sarah L; Barlowe, Charles

    2011-05-01

    Lipid sensing mechanisms at the endoplasmic reticulum (ER) coordinate an array of biosynthetic pathways. A major phospholipid regulatory circuit in yeast is controlled by Scs2p, an ER membrane protein that binds the transcriptional repressor protein Opi1p. Cells grown in the absence of inositol sequester Scs2p-Opi1p at the ER and derepress target genes including INO1. We recently reported that Yet1p and Yet3p, the yeast homologues of BAP29 and BAP31, are required for normal growth in the absence of inositol. Here we show that the Yet1p-Yet3p complex acts in derepression of INO1 through physical association with Scs2p-Opi1p. Yet complex binding to Scs2p-Opi1p was enhanced by inositol starvation, although the interaction between Scs2p and Opi1p was not influenced by YET1 or YET3 deletion. Interestingly, live-cell imaging analysis indicated that Opi1p does not efficiently relocalize to the ER during inositol starvation in yet3Δ cells. Together our data demonstrate that a physical association between the Yet complex and Scs2p-Opi1p is required for proper localization of the Opi1p repressor to ER membranes and subsequent INO1 derepression.

  1. Er:YAG laser debonding of porcelain veneers

    NASA Astrophysics Data System (ADS)

    Buu, Natalie; Morford, Cynthia; Finzen, Frederick; Sharma, Arun; Rechmann, Peter

    2010-02-01

    The removal of porcelain veneers using Er:YAG lasers has not been previously described in the scientific literature. This study was designed to systematically investigate the efficacy of an Er:YAG laser on veneer debonding without damaging the underlying tooth structure, as well as preserving a new or misplaced veneer. Initially, Fourier Transform Infrared Spectroscopy (FTIR) was used on flat porcelain veneer samples (IPS Empress Esthetic; Ivoclar Vivadent, Amherst, NY) to assess which infrared laser wavelengths are transmitted through the veneer. Additionally, FTIR spectra from a veneer bonding cement (RelyX Veneer Cement A1; 3M ESPE, St. Paul, MN) were obtained. While the veneer material showed no characteristic water absorption bands in the FTIR, the bonding cement has a broad H2O/OH absorption band coinciding with the ER:YAG laser emission wavelength. Consequently Er:YAG laser energy transmission through different veneer thicknesses was measured. The porcelain veneers transmitted 11 - 18 % of the incident Er:YAG laser energy depending on their thicknesses (Er:YAG laser: LiteTouch by Syneron; wavelength 2,940 nm, 10 Hz repetition rate, pulse duration 100 μs at 133 mJ/pulse; straight sapphire tip 1,100 μm diameter; Syneron, Yokneam, Israel). Initial signs of cement ablation occurred at approximately 1.8 - 4.0 J/cm2. This can be achieved by irradiating through the veneer with the fiber tip positioned at a distance of 3-6 mm from the veneer surface, and operating the Er:YAG laser with 133 mJ output energy. All eleven veneers bonded on extracted anterior incisor teeth were easily removed using the Er:YAG laser. The removal occurred without damaging underlying tooth structure as verified by light microscopic investigation (Incident Light Microscope Olympus B 50, Micropublisher RTV 3.3 MP, Image Pro software, Olympus). The debonding mainly occurred at the cement/veneer interface. When the samples were stored in saline solution for 5 days and/or an air-waterspray was

  2. ER bodies in plants of the Brassicales order: biogenesis and association with innate immunity

    PubMed Central

    Nakano, Ryohei T.; Yamada, Kenji; Bednarek, Paweł; Nishimura, Mikio; Hara-Nishimura, Ikuko

    2014-01-01

    The endoplasmic reticulum (ER) forms highly organized network structures composed of tubules and cisternae. Many plant species develop additional ER-derived structures, most of which are specific for certain groups of species. In particular, a rod-shaped structure designated as the ER body is produced by plants of the Brassicales order, which includes Arabidopsis thaliana. Genetic analyses and characterization of A. thaliana mutants possessing a disorganized ER morphology or lacking ER bodies have provided insights into the highly organized mechanisms responsible for the formation of these unique ER structures. The accumulation of proteins specific for the ER body within the ER plays an important role in the formation of ER bodies. However, a mutant that exhibits morphological defects of both the ER and ER bodies has not been identified. This suggests that plants in the Brassicales order have evolved novel mechanisms for the development of this unique organelle, which are distinct from those used to maintain generic ER structures. In A. thaliana, ER bodies are ubiquitous in seedlings and roots, but rare in rosette leaves. Wounding of rosette leaves induces de novo formation of ER bodies, suggesting that these structures are associated with resistance against pathogens and/or herbivores. ER bodies accumulate a large amount of β-glucosidases, which can produce substances that potentially protect against invading pests. Biochemical studies have determined that the enzymatic activities of these β-glucosidases are enhanced during cell collapse. These results suggest that ER bodies are involved in plant immunity, although there is no direct evidence of this. In this review, we provide recent perspectives of ER and ER body formation in A. thaliana, and discuss clues for the functions of ER bodies. We highlight defense strategies against biotic stress that are unique for the Brassicales order, and discuss how ER structures could contribute to these strategies. PMID

  3. GSK-3 mediated phosphorylation couples ER-Golgi transport and nuclear stabilisation of the CREB-H transcription factor to mediate Apolipoprotein secretion.

    PubMed

    Barbosa, Sónia; Carreira, Suzanne; O'Hare, Peter

    2017-04-05

    CREB-H, an ER-anchored transcription factor plays a key role in regulating secretion in metabolic pathways, particularly triglyceride homeostasis. It controls the production both of secretory pathway components and cargoes including apolipoproteins ApoA-IV and ApoC-II, contributing to VLDL/HDL distribution and lipolysis. The key mechanism controlling CREB-H activity involves its ER retention and forward transport to the Golgi, where it is cleaved by Golgi-resident proteases releasing the N-terminal product which traffics to the nucleus to effect transcriptional responses. Here we show that a serine-rich motif, termed the P-motif located in the N-terminus between serines 73 to 90, controls release of the precursor transmembrane form from the ER and its forward transport to the Golgi. This motif is subject to GSK-3 phosphorylation promoting ER-retention while mutation of target serines or drug inhibition of GSK-3 activity, co-ordinately induces both forward transport of the precursor and cleavage, resulting in nuclear import. We previously showed that for the nuclear product, the P-motif is subject to multiple phosphorylations which regulate stability by targeting the protein to the SCF(Fbw1a) E3 ubiquitin ligase. Thus phosphorylation at the P-motif provides integrated control of CREB-H function, coupling intercompartmental transport in the cytoplasm with stabilisation of the active form in the nucleus.

  4. Hippocampal ER stress and learning deficits following repeated pyrethroid exposure.

    PubMed

    Hossain, Muhammad M; DiCicco-Bloom, Emanuel; Richardson, Jason R

    2015-01-01

    Endoplasmic reticulum (ER) stress is implicated as a significant contributor to neurodegeneration and cognitive dysfunction. Previously, we reported that the widely used pyrethroid pesticide deltamethrin causes ER stress-mediated apoptosis in SK-N-AS neuroblastoma cells. Whether or not this occurs in vivo remains unknown. Here, we demonstrate that repeated deltamethrin exposure (3 mg/kg every 3 days for 60 days) causes hippocampal ER stress and learning deficits in adult mice. Repeated exposure to deltamethrin caused ER stress in the hippocampus as indicated by increased levels of C/EBP-homologous protein (131%) and glucose-regulated protein 78 (96%). This was accompanied by increased levels of caspase-12 (110%) and activated caspase-3 (50%). To determine whether these effects resulted in learning deficits, hippocampal-dependent learning was evaluated using the Morris water maze. Deltamethrin-treated animals exhibited profound deficits in the acquisition of learning. We also found that deltamethrin exposure resulted in decreased BrdU-positive cells (37%) in the dentate gyrus of the hippocampus, suggesting potential impairment of hippocampal neurogenesis. Collectively, these results demonstrate that repeated deltamethrin exposure leads to ER stress, apoptotic cell death in the hippocampus, and deficits in hippocampal precursor proliferation, which is associated with learning deficits.

  5. ER Ursae Majoris: A dwarf nova with surprises

    NASA Astrophysics Data System (ADS)

    de Miguel, Enrique; Patterson, Joe; Kemp, Jonathan; Stein, William; Roberts, George; Campbell, T.; Hambsch, Franz-J.; Krajci, Tom; Dvorak, Shawn; Koff, Robert A.; Morelle, Etienne; Potter, Michael; Cejudo, David; Brady, Steve; Menzies, Kenneth

    2012-05-01

    ER Ursae Majoris is a relatively bright member of the SU UMa-type dwarf novae that undergoes frequent eruptions of amplitude ~2 mag every ~4 d. In addition to these ordinary dwarf-nova outbursts, ER UMa shows brighter eruptions (superoutbursts) lasting ~20 d with a recurrence time of ~44 d. As other members of the SU UMa class, ER UMa displays a characteristic periodic modulation (superhumps) in its light curve during the course of a superoutburst, the period being a few percent longer than the orbital period of the underlying binary system. A routine photometric patrol of ER UMa during its January 2011superoutburst became much more interesting after noticing the presence of an additional modulation in its light curve, with a period slightly shorter than the orbital period. Similar photometric waves (known as negative superhumps) have already been observed in other cataclysmic variables, mainly in nova-like systems, but only in a small handful of SU UMa-type stars during quiescence, and never before during a superoutburst. We report in this communication the results of a worldwide photometric campaign that was orchestrated right after the discovery of negative superhumps in ER UMa, and provide a thorough analysis of the data obtained from more than 10 stations of the Center of Backyard Astrophysics (CBA) network, which include more than 1000 hours of photometric data over a 4-month baseline on 2011, and a similar (still in progress) dense coverage in 2012.

  6. ER-2: Flying Laboratory for Earth Science Studies

    NASA Technical Reports Server (NTRS)

    Navarro, Robert

    2007-01-01

    The National Aeronautics and Space Administration (NASA) Dryden Flight Research Center (DFRC), (Edwards, California, USA) has two Lockheed Martin Corporation (Bethesda, Maryland) Earth Research-2 (ER-2) aircraft that serve as high-altitude and long-range flying laboratories. The ER-2 has been utilized to conduct scientific studies of stratospheric and tropospheric chemistry, land-use mapping, disaster assessment, preliminary testing and calibration and validation of satellite sensors. The ER-2 aircraft provides experimenters with a wide array of payload accommodation areas with suitable environment control with required electrical and mechanical interfaces. Missions may be flown out of DFRC or from remote bases worldwide. The NASA ER-2 is utilized by a variety of customers, including U.S. Government agencies, civilian organizations, universities, and state governments. The combination of the ER-2 s range, endurance, altitude, payload power, payload volume and payload weight capabilities complemented by a trained maintenance and operations team provides an excellent and unique platform system to the science community.

  7. Towards Understanding ER Fluids Using Sals/rheometry

    NASA Astrophysics Data System (ADS)

    Crosby, Bryan J.; McLeish, Tom; Block, Harry

    This paper details work in Cranfield and Leeds Universities of making a stock of transparent ER fluids, which could later be utilised in a new optical electro rheometer (OER) to be assembled at Leeds University. Two basic routes were attempted. One was to use glass microspheres and the other was to use polymer spheres. In order to increase the strength of the ER effect, it was necessary to increase the volume loading while still maintaining sufficient transmission (about 75% over 2 mm). It was found to be possible to increase the ER effect quite substantially in some instances, and in others it was possible to get a near perfect refractive index match. It was not possible to combine both requirements in one fluid such that a high static yield stress was apparent in a transparent ER fluid. However one fluid was made which gave acceptable diffraction losses at high volume fractions, remained in suspension for extended periods and provide about 700 Pa yield stress at 4kV/mm and about 30% volume fraction viz: untreated poly(ethylene vinyl acetate) microspheres in Cereclor/bromonaphthalene/polystyrene solution. The OER being assembled at Leeds University is intended to record small angle light scattering (SALS) profiles, electrical and mechanical properties of ER fluids simultaneously. The OER is based around a DSR 500 machine purchased from Rheometric Scientific with quartz tools coated with transparent indium tin oxide(ITO), which is capable of measuring both steady state (DC) and oscillatory (AC) material parameters.

  8. Excitation mechanisms of Er optical centers GaN epilayers

    NASA Astrophysics Data System (ADS)

    Hawkins, Matthew; Jiang, Hongxing; Lin, Jingyu; Zavada, John; Vinh, Nguyen

    We report direct evidence of two mechanisms responsible for the excitation of optically active Er3 + ions in GaN epilayers grown by metal-organic chemical vapor deposition. These mechanisms, resonant excitation via the higher-lying inner 4f shell transitions and band-to-band excitation of the semiconductor host, lead to narrow emission lines from isolated and the defect-related Er optical centers. However, these centers have different photoluminescence spectra, local defect environments, decay dynamics, and excitation cross sections. The photoluminescence at 1.54 micrometer from the isolated Er optical center which can be excited by either mechanism has the same decay dynamics, but possesses a much higher excitation cross-section under band-to-band excitation. In contrast, the photoluminescence at 1.54 micrometer from the defect-related Er optical center can only be observed through band-to-band excitation but has the largest excitation cross-section. These results explain the difficulty in achieving gain in Er doped GaN and indicate approaches for realization of optical amplification, and possibly lasing, at room temperature.

  9. PERK-mediated Autophagy in Osteosarcoma Cells Resists ER Stress-induced Cell Apoptosis

    PubMed Central

    Ji, Guang-rong; Yu, Nai-chun; Xue, Xiang; Li, Zong-guang

    2015-01-01

    Osteosarcoma is a bone cancer that develops commonly in children and adolescents. However, osteosarcoma treatments often fail by the development of chemoresistance to apoptosis, and the molecular mechanisms remain unclear. In this study, we propose that autophagy is responsible for osteosarcomatous resistance to apoptosis. We implicate PERK-mediated autophagy as a significant contributor to apoptosis resistance due to ER stress in osteosarcoma cells. By immunostainings and western blots, we identified that PERK activated osteosarcomatous autophagy via inhibiting mTORC1 pathway, thereby preventing cell apoptosis. While using RNAi, we knocked down PERK and found that autophagy was suppressed, result in osteosarcomatous apoptosis. Our results identify a novel role of PERK-mediated autophagy as a significant mechanism for osteosarcoma cell survival. These results will help to understand the mechanism of chemoresistance in osteosarcoma cells, and indicate a novel target for improving osteosarcoma therapy. PMID:26078722

  10. PERK-mediated Autophagy in Osteosarcoma Cells Resists ER Stress-induced Cell Apoptosis.

    PubMed

    Ji, Guang-rong; Yu, Nai-chun; Xue, Xiang; Li, Zong-guang

    2015-01-01

    Osteosarcoma is a bone cancer that develops commonly in children and adolescents. However, osteosarcoma treatments often fail by the development of chemoresistance to apoptosis, and the molecular mechanisms remain unclear. In this study, we propose that autophagy is responsible for osteosarcomatous resistance to apoptosis. We implicate PERK-mediated autophagy as a significant contributor to apoptosis resistance due to ER stress in osteosarcoma cells. By immunostainings and western blots, we identified that PERK activated osteosarcomatous autophagy via inhibiting mTORC1 pathway, thereby preventing cell apoptosis. While using RNAi, we knocked down PERK and found that autophagy was suppressed, result in osteosarcomatous apoptosis. Our results identify a novel role of PERK-mediated autophagy as a significant mechanism for osteosarcoma cell survival. These results will help to understand the mechanism of chemoresistance in osteosarcoma cells, and indicate a novel target for improving osteosarcoma therapy.

  11. Possible role of the aromatase-independent steroid metabolism pathways in hormone responsive primary breast cancers.

    PubMed

    Hanamura, Toru; Niwa, Toshifumi; Gohno, Tatsuyuki; Kurosumi, Masafumi; Takei, Hiroyuki; Yamaguchi, Yuri; Ito, Ken-ichi; Hayashi, Shin-ichi

    2014-01-01

    Aromatase inhibitors (AIs) exert antiproliferative effects by reducing local estrogen production from androgens in postmenopausal women with hormone-responsive breast cancer. Previous reports have shown that androgen metabolites generated by the aromatase-independent enzymes, 5α-androstane-3β, 17β-diol (3β-diol), androst-5-ene-3β, and 17β-diol (A-diol), also activate estrogen receptor (ER) α. Estradiol (E2) can also reportedly be generated from estrone sulfate (E1S) pooled in the plasma. Estrogenic steroid-producing aromatase-independent pathways have thus been proposed as a mechanism of AI resistance. However, it is unclear whether these pathways are functional in clinical breast cancer. To investigate this issue, we assessed the transcriptional activities of ER in 45 ER-positive human breast cancers using the adenovirus estrogen-response element-green fluorescent protein assay and mRNA expression levels of the ER target gene, progesterone receptor, as indicators of ex vivo and in vivo ER activity, respectively. We also determined mRNA expression levels of 5α-reductase type 1 (SRD5A1) and 3β-hydroxysteroid dehydrogenase type 1 (3β-HSD type 1; HSD3B1), which produce 3β-diol from androgens, and of steroid sulfatase (STS) and 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD type 1; HSD17B1), which produce E2 or A-diol from E1S or dehydroepiandrosterone sulfate. SRD5A1 and HSD3B1 expression levels were positively correlated with ex vivo and in vivo ER activities. STS and HSD17B1 expression levels were positively correlated with in vivo ER activity alone. Elevated expression levels of these steroid-metabolizing enzymes in association with high in vivo ER activity were particularly notable in postmenopausal patients. Analysis of the expression levels of steroid-metabolizing enzymes revealed positive correlations between SRD5A1 and HSD3B1, and STS and HSD17B1. These findings suggest that the SRD5A1-HSD3B1 as well as the STS-HSD17B pathways, could contributes

  12. Optical characterization, luminescence properties of Er3+ and Er3+/Yb3+ co-doped tellurite glasses for broadband amplification

    NASA Astrophysics Data System (ADS)

    Meruva, Seshadri; Carlos, Barbosa Luiz; Alberto Peres, Ferencz Junior Julio

    2014-03-01

    In the present paper, optical absorption and emission spectra and luminescence decay lifetimes of different concentrations, 0.1, 0.3, 0.5, 0.7 and 1.0 mol% of Er3+ and 0.1Er3+/0.5Yb3+ co-doped tellurite glasses (TeO2-Bi2O3-ZnONb2O5) were reported. Judd-Ofelt intensity parameters were determined and used to calculate spontaneous radiative transition probabilities (Arad), radiative lifetimes (τR), branching ratios (β) and stimulated emission cross-sections (σP) for certain emission transitions. NIR emission at 1.5μm and up-conversion spectra of Er3+ and Er3+/Yb3+ co-doped tellurite glasses were measured under excitation wavelength of 980 nm. The absorption, emission and gain cross-sections for 4I13/2→4I15/2 transition of Er3+ are determined. The peak emission cross-section of this transition is found to be higher (9.95×10-21 cm2) for 0.1 mol% of Er3+ and lower (6.81×10-21 cm2) for 1.0 mol% of Er3+ doped tellurite glasses, which is comparable to other oxide glasses. The larger peak emission cross-section for lower concentration of Er3+ is due to the high refractive index of glass matrix (2.1547), relation established from Judd-Ofelt theory. The observed full-widths at half maxima (FWHM) for lower and higher concentrations of Er3+ are 64nm and 96 nm respectively. The larger values of FWHM and peak emission cross-sections are potentially useful for optical amplification processes in the design of Erbium doped fiber amplifiers (EDFs). Under 980 nm excitation three strong up-conversion bands were observed at 530nm, 546nm and 665nm. The pump power dependent intensities and mechanisms involved in the up-conversion process have been studied. The luminescence decay profiles for 4I13/2 level were reported for all glass matrices.

  13. Er-doped and Er, Yb co-doped oxyfluoride glasses and glass-ceramics, structural and optical properties

    NASA Astrophysics Data System (ADS)

    Lisiecki, Radosław; Augustyn, Elżbieta; Ryba-Romanowski, Witold; Żelechower, Michał

    2011-09-01

    The selected glasses and glass-ceramics pertinent to following chemical composition in mol%:48%SiO 2-11%Al 2O 3-7%Na 2O-10%CaO-10%PbO-11%PbF 2-3%ErF 3 and 48%SiO 2-11%Al 2O 3-7%Na 2O-10%CaO-10%PbO-10%PbF 2-1%ErF 3-3%YbF 3 have been manufactured from high purity components (Aldrich) at 1450 °C in normal atmosphere. Glass optical fibers were successfully drawn. Subsequently they were subject to the heat-treatment at 700 °C in various time periods. The preceding differential thermal analysis (DTA) studies allowed estimating both the fiber drawing temperature and the controlled crystallization temperature of glass fibers. It has been observed that the controlled heat-treatment of oxyfluoride glass fibers results in the creation of Pb 5Al 3F 19, Er 4F 2O 11Si 3 and Er 3FO 10Si 3 crystalline phases. The identified phases were characterized by X-ray powder diffraction (XRD) and confirmed by selected area electron diffraction (SAED). The fibers consist of mixed amorphous-crystalline microstructure with nano-crystals of size even below 10 nm distributed in the glassy host. Their morphology was investigated applying high-resolution transmission electron microscopy. Optical properties and excited state relaxation dynamics of optically active ions (Er 3+, Yb 3+) in glass and glass-ceramics have been studied. Based on absorption spectra the Judd-Ofelt analysis was carried out. The main attention was directed to NIR luminescence at. 1.6 μm related to 4I 13/2 → 4I 15/2 Er 3+ and less effective emission associated with 4I 11/2 → 4I 15/2 Er 3+ and 2F 5/2 → 2F 7/2 Yb 3+ transitions. The dissimilar spectroscopic properties have been revealed for glasses and glass-ceramic samples, respectively. The reduction of emission linewidth at 1.6 and 1.0 μm combined with substantial increase of 4I 13/2 lifetimes of erbium in glass-ceramics appear to be evidences that Er 3+ ions are accommodated in crystalline phases. The structural and optical characteristics of oxyfluoride glass

  14. Biological properties of ER 42859, a novel erythromycin derivative.

    PubMed

    Wilson, J M; Hannan, P C; Shillingford, C; Knowles, D J

    1989-03-01

    The antimicrobial activity of a new semi-synthetic oral erythromycin derivative, ER 42859, was evaluated in vitro and in vivo in comparison with erythromycin, spiramycin, josamycin, oleandomycin and the newer semi-synthetic derivatives flurithromycin, roxithromycin and A-56268. MIC values of ER 42859 were superior to those of roxithromycin, oleandomycin, josamycin and spiramycin but generally 2-fold poorer than those of erythromycin. The activity equalled that of erythromycin against Haemophilus influenzae and was superior to that of roxithromycin and A-56268 against this organism. MIC values of the compound were greatly influenced by pH due to the dibasic nature of the molecule. ER 42859 had markedly superior activity to erythromycin, spiramycin, josamycin, oleandomycin and flurithromycin against experimental infections in mice and similar activity to roxithromycin and A-56268. Blood and tissue levels were high and prolonged in rodents. In volunteers, blood levels were prolonged but inferior to those of erythromycin.

  15. Residual vibration suppression of flexible arms using ER adaptive structures

    NASA Astrophysics Data System (ADS)

    Wei, Kexiang; Meng, Guang; Tang, Huanqing; Liu, Yingchun

    2007-07-01

    In the past decades, there have been a number of research activities to control unwanted vibration of flexible robot arms. The electrorheological (ER) adaptive structures, which behave as viscoelastic damping structures with controllable shear modulus, are used to suppress the residual vibrations of the rotating flexible arm in this study. The flexible arm is designed as an ER sandwich structures, in which ER fluids is sandwiched between two elastic surface layers. Experimental tests are conducted. The vibration response performances of the beam subjected to different electric field intensity and motion conditions are demonstrated and evaluated. The experimental results obtained indicate that significant vibration attenuation is achieved at different operating conditions by applying an electric field to the rotating flexible arm.

  16. Er:YAG laser metal and ceramic bracket debonding

    NASA Astrophysics Data System (ADS)

    Dostálová, Tat'jana; Remeš, Marek; Jelínková, Helena; Å ulc, Jan; Němec, Michal; Vyhlídal, David

    2016-02-01

    The goal of the study was investigation of Er:YAG radiation (wavelength 2.94 μm) interaction with various metal and ceramic brackets and adhesive materials. The source of radiation was a free-running Er: YAG laser generating pulses with energy 280 mJ, 250 μs long and repetition rate 6 Hz (mean power 1.7 W). During the treatment lasting 140 s, water cooling was implemented and only the brackets were irradiated. It has been observed that the brackets were removed easily after the Er:YAG laser irradiation, and temperature rise was limited also for metal brackets. SEM investigation has confirmed less damage of enamel in comparison with non-irradiated samples.

  17. Ultra-High Spin Spectroscopy In Er Nuclei

    SciTech Connect

    Simpson, J.

    2008-11-11

    The discoveries observed in the ongoing conflict between collective and single-particle nuclear behaviour with increasing angular momentum have driven the field of nuclear spectroscopy for many decades and have given rise to new nuclear phenomena. Recently a new frontier of {gamma} spectroscopy at ultra-high spin has been opened in the rare-earth region with rotational bands that bypass the classic band-terminating states that appear at spin 45({Dirac_h}/2{pi}) in the N 90 Er nuclei. These weakly populated rotational structures have characteristics of triaxial strongly-deformed bands. Such structures have been observed in {sup 157,158,160}Er, following a series of experiments using the Gammasphere spectrometer. These observations herald a return to collective excitations at spins of about 50 to 65({Dirac_h}/2{pi}). This talk reviews the status of the spectroscopy and understanding of the observed structures in these Er and neighbouring nuclei.

  18. Phosphoinositide kinase signaling controls ER-PM cross-talk

    PubMed Central

    Omnus, Deike J.; Manford, Andrew G.; Bader, Jakob M.; Emr, Scott D.; Stefan, Christopher J.

    2016-01-01

    Membrane lipid dynamics must be precisely regulated for normal cellular function, and disruptions in lipid homeostasis are linked to the progression of several diseases. However, little is known about the sensory mechanisms for detecting membrane composition and how lipid metabolism is regulated in response to membrane stress. We find that phosphoinositide (PI) kinase signaling controls a conserved PDK-TORC2-Akt signaling cascade as part of a homeostasis network that allows the endoplasmic reticulum (ER) to modulate essential responses, including Ca2+-regulated lipid biogenesis, upon plasma membrane (PM) stress. Furthermore, loss of ER-PM junctions impairs this protective response, leading to PM integrity defects upon heat stress. Thus PI kinase–mediated ER-PM cross-talk comprises a regulatory system that ensures cellular integrity under membrane stress conditions. PMID:26864629

  19. Tapentadol-ER for the treatment of diabetic peripheral neuropathy.

    PubMed

    Games, Gina; Hutchison, Amber

    2013-10-01

    With the prevalence of diabetes mellitus (DM) increasing, pathologic complications such as diabetic peripheral neuropathy (DPN) are also becoming more common. Of those diagnosed with DM, 10% to 20% of patients suffer from painful DPN. Until recently, only pregabalin and duloxetine possessed Food and Drug Administration (FDA) approval for this condition. However, FDA recently approved tapentadol-ER [extended release] (Nucynta ER) for painful DPN. Tapentadol-ER is an opioid analgesic commonly used for the treatment of moderate-to-severe chronic pain that contains a unique dual mechanism acting as both a weak mu-opiod receptor agonist and norepinephine-reuptake inhibitor. It is by way of this unique dual mechanism that allows for effective analgesic effects with increased tolerability. This new FDA approval provides an additional therapeutic option to treat DPN in symptomatic patients.

  20. The Role of ER Bodies in Brassicaceae Resistance under Clinorotation

    NASA Astrophysics Data System (ADS)

    Romanchuk, S. M.; Kordyum, E. L.

    2013-02-01

    Results of the electron-microscopic investigation of root apices of Arabidopsis thaliana 3- and 7-day old seedlings grown in the stationary conditions and under clinorotation are presented. It was shown the similarity in the root apex cell ultrastructure in control and under clinorotation. In the same time there were some differences in the ultrustructure of statocytes and the distal elongation zone under clinorotation. For the first time, the sensitivity of ER-bodies, which are derivative of granular endoplasmic reticulum and contain a β-glucosidase enzyme, to the influence of simulated microgravity that was demonstrated by increasing quantity and area of ER-bodies per cell section, as well as by higher variability of their shape under clinorotation. A degree of these changes correlated with the duration of clinorotation. On the basis of obtained data, a protective role of ER-bodies in adaptation of plants to microgravity is discussed.

  1. Bidentate ligands on osmium(VI) nitrido complexes control intracellular targeting and cell death pathways.

    PubMed

    Suntharalingam, Kogularamanan; Johnstone, Timothy C; Bruno, Peter M; Lin, Wei; Hemann, Michael T; Lippard, Stephen J

    2013-09-25

    The cellular response evoked by antiproliferating osmium(VI) nitrido compounds of general formula OsN(N^N)Cl3 (N^N = 2,2'-bipyridine 1, 1,10-phenanthroline 2, 3,4,7,8-tetramethyl-1,10-phenanthroline 3, or 4,7-diphenyl-1,10-phenanthroline 4) can be tuned by subtle ligand modifications. Complex 2 induces DNA damage, resulting in activation of the p53 pathway, cell cycle arrest at the G2/M phase, and caspase-dependent apoptotic cell death. In contrast, 4 evokes endoplasmic reticulum (ER) stress leading to the upregulation of proteins of the unfolded protein response pathway, increase in ER size, and p53-independent apoptotic cell death. To the best of our knowledge, 4 is the first osmium compound to induce ER stress in cancer cells.

  2. Innate Immunity at Mucosal Surfaces: the IRE1-RIDD-RIG-I Pathway

    PubMed Central

    Lencer, Wayne I.; DeLuca, Heidi; Grey, Michael J.; Cho, Jin Ah

    2015-01-01

    Recent studies have linked the ER stress sensor IRE1α with the RIG-I pathway, which triggers an inflammatory response upon detection of viral RNAs. In response to ER dysfunction, IRE1α cleaves mRNA into single-strand fragments that lack markers of self, which activate RIG-I. Certain microbial products from mucosal pathogens activate this pathway by binding IRE1α directly, and the discovery that IRE1 is amplified at mucosal surfaces by gene duplication suggests an important role for IRE1 in mucosal immunity. Here, we review evidence in support of this hypothesis, and propose a model wherein IRE1 surveys the integrity of the ER, acting as a guard receptor and a pattern recognition receptor, capable both of sensing cellular stress caused by microbial infection and of responding to pathogens directly. PMID:26093676

  3. Optical properties of Er3+ ions doped in oxyfluoroborate glass.

    PubMed

    Kumar, Akshaya; Rai, D K; Rai, S B

    2002-12-01

    In this paper the Stark components of 4S(3/2), 2H(11/2) and 4I(15/2) levels of Er3+ ion doped in oxyfluoroborate glass have been resolved using laser excitation and fluorescence measurements. The lifetime of 4S(3/2) level as a function of Er3+ concentration in the glass host has also been measured. Concentration quenching due to interaction among rare earth ions and the mechanism responsible for the same has been elucidated. The Judd-Ofelt analysis of the absorption spectrum has also been carried out.

  4. Orchestration of secretory protein folding by ER chaperones

    PubMed Central

    Gidalevitz, Tali; Stevens, Fred; Argon, Yair

    2013-01-01

    The endoplasmic reticulum is a major compartment of protein biogenesis in the cell, dedicated to production of secretory, membrane and organelle proteins. The secretome has distinct structural and post-translational characteristics, since folding in the ER occurs in an environment that is distinct in terms of its ionic composition, dynamics and requirements for quality contol. The folding machinery in the ER therefore includes chaperones and folding enzymes that introduce, monitor and react to disulfide bonds, glycans, and fluctuations of luminal calcium. We describe the major chaperone networks in the lumen and discuss how they have distinct modes of operation that enable cells to accomplish highly efficient production of the secretome. PMID:23507200

  5. Pilot James Barrilleaux with ER-2 aircraft on ramp

    NASA Technical Reports Server (NTRS)

    1998-01-01

    James Barrilleaux is the assistant chief pilot for ER-2s in the Flight Crew Branch of NASA's Dryden Flight Research Center, Edwards, California. The ER-2s--civilian variants of the military U-2S reconnaissance aircraft--are part of NASA's Airborne Science program. The ER-2s can carry airborne scientific payloads of up to 2,600 pounds to altitudes of about 70,000 feet to investigate such matters as earth resources, celestial phenomena, atmospheric chemistry and dynamics, and oceanic processes. Barrilleaux has held his current position since February 1998. Barrilleaux joined NASA in 1986 as a U-2/ER-2 pilot with NASA's Airborne Science program at Ames Research Center, Moffett Field, California. He flew both the U-2C (until 1989) and the ER-2 on a wide variety of missions both domestic and international. Barrilleaux flew high-altitude operations over Antarctica in which scientific instruments aboard the ER-2 defined the cause of ozone depletion over the continent, known as the ozone hole. He has also flown the ER-2 over the North Pole. Barrilleaux served for 20 years in the U.S. Air Force before he joined NASA. He completed pilot training at Reese Air Force Base, Lubbock, Texas, in 1966. He flew 120 combat missions as a F-4 fighter pilot over Laos and North Vietnam in 1970 and 1971. He joined the U-2 program in 1974, becoming the commander of an overseas U-2 operation in 1982. In 1983, he became commander of the squadron responsible for training all U-2 pilots and SR-71 crews located at Beale Air Force Base, Marysville, California. He retired from the Air Force as a lieutenant colonel in 1986. On active duty, he flew the U-2, F-4 Phantom, the T-38, T-37, and the T-33. His decorations included two Distinguished Flying Crosses, 12 Air Medals, two Meritorious Service Medals, and other Air Force and South Vietnamese awards. Barrilleaux earned a bachelor of science degree in chemical engineering from Texas A&M University, College Station, in 1964 and a master of science

  6. Next generation Er:YAG fractional ablative laser

    NASA Astrophysics Data System (ADS)

    Heinrich, A.; Vizhanyo, A.; Krammer, P.; Summer, S.; Gross, S.; Bragagna, T.; Böhler, C.

    2011-03-01

    Pantec Biosolutions AG presents a portable fractional ablative laser system based on a miniaturized diode pumped Er:YAG laser. The system can operate at repetition rates up to 500 Hz and has an incorporated beam deflection unit. It is smaller, lighter and cost efficient compared to systems based on lamp pumped Er:YAG lasers and incorporates a skin layer detection to guarantee precise control of the microporation process. The pulse parameters enable a variety of applications in dermatology and in general medicine, as demonstrated by first results on transdermal drug delivery of FSH (follicle stimulating hormone).

  7. ADMiER-ing thin but complex fluids

    NASA Astrophysics Data System (ADS)

    McDonnell, Amarin G.; Bhattacharjee, Pradipto K.; Pan, Sharadwata; Hill, David; Danquah, Michael K.; Friend, James R.; Yeo, Leslie Y.; Prabhakar, Ranganathan

    2011-12-01

    The Acoustics Driven Microfluidic Extensional Rheometer (ADMiER) utilises micro litre volumes of liquid, with viscosities as low as that of water, to create valid and observable extensional flows, liquid bridges that pinch off due to capillary forces in this case. ADMiER allows the study fluids that have been beyond conventional methods and also study more subtle fluid properties. We can observe polymeric fluids with solvent viscosities far below those previously testable, accentuating elastic effects. Also, it has enabled the testing of aqueous solutions of living motile particles, which significantly change fluid properties, opening up the potential for diagnostic applications.

  8. Ocean wind field measurement performance of the ERS-1 scatterometer

    NASA Technical Reports Server (NTRS)

    Hans, P.; Schuessler, H.

    1984-01-01

    The Active Microwave Instrumentation (AMI), which will be implemented on the ERS-1, is a 5.3 GHz multipurpose radar for land surface imaging, ocean wave spectrum measurement and wind observations over oceans. The imaging and wave measurements apply Synthetic Aperture Radar (SAR) techniques, while wind field detection is performed by the Scatterometer as part of the AMI. The Scatterometer system design was developed and optimized with the aid of a performance simulator. This paper, aimed at giving an overview, is presented about the: (1) ERS-1 Scatterometer system design; (2) Error budget; and the (3) Overall calibration concept.

  9. Two-phonon excitations in 170Er

    SciTech Connect

    Archer, D E; Becker, J A; Bernstein, L A; Garrett, P E; Johns, G D; Kadi, M; Martin, A; Nelson, R O; Warr, N; Wilburn, W S; Yates, S W; Younes, W

    1998-09-29

    Recent experiments at the GEANIE/WNR facility and the University of Kentucky accelerator have yielded strong evidence for a two-gamma excitation in 170Er. This new case can be added to a handful of previously identified examples of two-gamma vibrations, all of them discovered in this decade. In this paper the experimental evidence for a two-phonon excitation 170Er is presented and the current state of understanding of these structures is reviewed in the context of this and other recent findings.

  10. HDLs protect pancreatic β-cells against ER stress by restoring protein folding and trafficking.

    PubMed

    Pétremand, Jannick; Puyal, Julien; Chatton, Jean-Yves; Duprez, Jessica; Allagnat, Florent; Frias, Miguel; James, Richard W; Waeber, Gérard; Jonas, Jean-Christophe; Widmann, Christian

    2012-05-01

    Endoplasmic reticulum (ER) homeostasis alteration contributes to pancreatic β-cell dysfunction and death and favors the development of diabetes. In this study, we demonstrate that HDLs protect β-cells against ER stress induced by thapsigargin, cyclopiazonic acid, palmitate, insulin overexpression, and high glucose concentrations. ER stress marker induction and ER morphology disruption mediated by these stimuli were inhibited by HDLs. Using a temperature-sensitive viral glycoprotein folding mutant, we show that HDLs correct impaired protein trafficking and folding induced by thapsigargin and palmitate. The ability of HDLs to protect β-cells against ER stress was inhibited by brefeldin A, an ER to Golgi trafficking blocker. These results indicate that HDLs restore ER homeostasis in response to ER stress, which is required for their ability to promote β-cell survival. This study identifies a cellular mechanism mediating the beneficial effect of HDLs on β-cells against ER stress-inducing factors.

  11. HDLs Protect Pancreatic β-Cells Against ER Stress by Restoring Protein Folding and Trafficking

    PubMed Central

    Pétremand, Jannick; Puyal, Julien; Chatton, Jean-Yves; Duprez, Jessica; Allagnat, Florent; Frias, Miguel; James, Richard W.; Waeber, Gérard; Jonas, Jean-Christophe; Widmann, Christian

    2012-01-01

    Endoplasmic reticulum (ER) homeostasis alteration contributes to pancreatic β-cell dysfunction and death and favors the development of diabetes. In this study, we demonstrate that HDLs protect β-cells against ER stress induced by thapsigargin, cyclopiazonic acid, palmitate, insulin overexpression, and high glucose concentrations. ER stress marker induction and ER morphology disruption mediated by these stimuli were inhibited by HDLs. Using a temperature-sensitive viral glycoprotein folding mutant, we show that HDLs correct impaired protein trafficking and folding induced by thapsigargin and palmitate. The ability of HDLs to protect β-cells against ER stress was inhibited by brefeldin A, an ER to Golgi trafficking blocker. These results indicate that HDLs restore ER homeostasis in response to ER stress, which is required for their ability to promote β-cell survival. This study identifies a cellular mechanism mediating the beneficial effect of HDLs on β-cells against ER stress-inducing factors. PMID:22399686

  12. Unraveling the role of ER stress inhibitors in the context of metabolic diseases.

    PubMed

    Sarvani, Chodisetty; Sireesh, Dornadula; Ramkumar, Kunka Mohanram

    2017-02-22

    ER stress is provoked by the accumulation of unfolded and misfolded proteins in the ER lumen leading to perturbations in ER homeostasis. ER stress activates a signaling cascade called the Unfolded Protein Response (UPR) which triggers a set of transcriptional and translational events that restore ER homeostasis, promoting cell survival and adaptation. If this adaptive response fails, a terminal UPR program commits such cells to apoptosis. Existing preclinical and clinical evidence testify that prolonged ER stress escalates the risk of several metabolic disorders including diabetes, obesity and dyslipidemia. There have been considerable efforts to develop small molecules that are capable of ameliorating ER stress. Few naturally occurring and synthetic molecules have already been demonstrated for their efficacy in abrogating ER stress in both in vitro and in vivo models of metabolic disorders. This review provides a broad overview of the molecular mechanisms of inhibition of ER stress and its association with various metabolic diseases.

  13. ER-resident proteins PDR2 and LPR1 mediate the developmental response of root meristems to phosphate availability

    PubMed Central

    Ticconi, Carla A.; Lucero, Rocco D.; Sakhonwasee, Siriwat; Adamson, Aaron W.; Creff, Audrey; Nussaume, Laurent; Desnos, Thierry; Abel, Steffen

    2009-01-01

    Inadequate availability of inorganic phosphate (Pi) in the rhizosphere is a common challenge to plants, which activate metabolic and developmental responses to maximize Pi acquisition. The sensory mechanisms that monitor environmental Pi status and regulate root growth via altered meristem activity are unknown. Here, we show that phosphate deficiency response 2 (PDR2) encodes the single P5-type ATPase of Arabidopsis thaliana. PDR2 functions in the endoplasmic reticulum (ER) and is required for proper expression of scarecrow (SCR), a key regulator of root patterning, and for stem-cell maintenance in Pi-deprived roots. We further show that the multicopper oxidase encoded by low phosphate root 1 (LPR1) is targeted to the ER and that LPR1 and PDR2 interact genetically. Because the expression domains of both genes overlap in the stem-cell niche and distal root meristem, we propose that PDR2 and LPR1 function together in an ER-resident pathway that adjusts root meristem activity to external Pi. Our data indicate that the Pi-conditional root phenotype of pdr2 is not caused by increased Fe availability in low Pi; however, Fe homeostasis modifies the developmental response of root meristems to Pi availability. PMID:19666499

  14. Hormone-Related Pathways and Risk of Breast Cancer Subtypes in African American Women

    PubMed Central

    Haddad, Stephen A.; Lunetta, Kathryn L.; Ruiz-Narváez, Edward A.; Bensen, Jeannette T.; Hong, Chi-Chen; Sucheston-Campbell, Lara E.; Yao, Song; Bandera, Elisa V.; Rosenberg, Lynn; Haiman, Christopher A.; Troester, Melissa A.; Ambrosone, Christine B.; Palmer, Julie R.

    2016-01-01

    Purpose We sought to investigate genetic variation in hormone pathways in relation to risk of overall and subtype-specific breast cancer in women of African ancestry (AA). Methods Genotyping and imputation yielded data on 143,934 SNPs in 308 hormone-related genes for 3663 breast cancer cases (1098 ER-, 1983 ER+, 582 ER unknown) and 4687 controls from the African American Breast Cancer Epidemiology and Risk (AMBER) Consortium. AMBER includes data from four large studies of AA women: the Carolina Breast Cancer Study, the Women's Circle of Health Study, the Black Women's Health Study, and the Multiethnic Cohort Study. Pathway- and gene-based analyses were conducted, and single SNP tests were run for the top genes. Results There were no strong associations at the pathway level. The most significantly associated genes were GHRH, CALM2, CETP, and AKR1C1 for overall breast cancer (gene-based nominal p ≤0.01); NR0B1, IGF2R, CALM2, CYP1B1, and GRB2 for ER+ breast cancer (p ≤0.02); and PGR, MAPK3, MAP3K1, and LHCGR for ER- disease (p ≤0.02). Single-SNP tests for SNPs with pairwise linkage disequilibrium r2 <0.8 in the top genes identified 12 common SNPs (in CALM2, CETP, NR0B1, IGF2R, CYP1B1, PGR, MAPK3, and MAP3K1) associated with overall or subtype-specific breast cancer after gene-level correction for multiple testing. Rs11571215 in PGR (progesterone receptor) was the SNP most strongly associated with ER- disease. Conclusion We identified eight genes in hormone pathways that contain common variants associated with breast cancer in AA women after gene-level correction for multiple testing. PMID:26458823

  15. Hormone-related pathways and risk of breast cancer subtypes in African American women.

    PubMed

    Haddad, Stephen A; Lunetta, Kathryn L; Ruiz-Narváez, Edward A; Bensen, Jeannette T; Hong, Chi-Chen; Sucheston-Campbell, Lara E; Yao, Song; Bandera, Elisa V; Rosenberg, Lynn; Haiman, Christopher A; Troester, Melissa A; Ambrosone, Christine B; Palmer, Julie R

    2015-11-01

    We sought to investigate genetic variation in hormone pathways in relation to risk of overall and subtype-specific breast cancer in women of African ancestry (AA). Genotyping and imputation yielded data on 143,934 SNPs in 308 hormone-related genes for 3663 breast cancer cases (1098 ER-, 1983 ER+, 582 ER unknown) and 4687 controls from the African American Breast Cancer Epidemiology and Risk (AMBER) Consortium. AMBER includes data from four large studies of AA women: the Carolina Breast Cancer Study, the Women's Circle of Health Study, the Black Women's Health Study, and the Multiethnic Cohort Study. Pathway- and gene-based analyses were conducted, and single-SNP tests were run for the top genes. There were no strong associations at the pathway level. The most significantly associated genes were GHRH, CALM2, CETP, and AKR1C1 for overall breast cancer (gene-based nominal p ≤ 0.01); NR0B1, IGF2R, CALM2, CYP1B1, and GRB2 for ER+ breast cancer (p ≤ 0.02); and PGR, MAPK3, MAP3K1, and LHCGR for ER- disease (p ≤ 0.02). Single-SNP tests for SNPs with pairwise linkage disequilibrium r (2) < 0.8 in the top genes identified 12 common SNPs (in CALM2, CETP, NR0B1, IGF2R, CYP1B1, PGR, MAPK3, and MAP3K1) associated with overall or subtype-specific breast cancer after gene-level correction for multiple testing. Rs11571215 in PGR (progesterone receptor) was the SNP most strongly associated with ER- disease. We identified eight genes in hormone pathways that contain common variants associated with breast cancer in AA women after gene-level correction for multiple testing.

  16. Pahute Mesa Well Development and Testing Analyses for Wells ER-20-7, ER-20-8 #2, and ER-EC-11, Revision 1

    SciTech Connect

    Greg Ruskauff

    2011-12-01

    This report analyzes the following data collected from ER-20-7, ER-20-8 No.2, and ER-EC-11 during WDT operations: (1) Chemical indicators of well development (Section 2.0); (2) Static hydraulic head (Section 3.0); (3) Radiochemistry and geochemistry (Section 4.0); (4) Drawdown observed at locations distal to the pumping well (Section 5.0); and (5) Drilling water production, flow logs, and temperature logs (Section 6.0). The new data are further considered with respect to existing data as to how they enhance or change interpretations of groundwater flow and transport, and an interim small-scale conceptual model is also developed and compared to Phase I concepts. The purpose of well development is to remove drilling fluids and drilling-associated fines from the formation adjacent to a well so samples reflecting ambient groundwater water quality can be collected, and to restore hydraulic properties near the well bore. Drilling fluids can contaminate environmental samples from the well, resulting in nonrepresentative measurements. Both drilling fluids and preexisting fines in the formation adjacent to the well can impede the flow of water from the formation to the well, creating artifacts in hydraulic response data measured in the well.

  17. The ER Stress Sensor PERK Coordinates ER-Plasma Membrane Contact Site Formation through Interaction with Filamin-A and F-Actin Remodeling.

    PubMed

    van Vliet, Alexander R; Giordano, Francesca; Gerlo, Sarah; Segura, Inmaculada; Van Eygen, Sofie; Molenberghs, Geert; Rocha, Susana; Houcine, Audrey; Derua, Rita; Verfaillie, Tom; Vangindertael, Jeroen; De Keersmaecker, Herlinde; Waelkens, Etienne; Tavernier, Jan; Hofkens, Johan; Annaert, Wim; Carmeliet, Peter; Samali, Afshin; Mizuno, Hideaki; Agostinis, Patrizia

    2017-03-02

    Loss of ER Ca(2+) homeostasis triggers endoplasmic reticulum (ER) stress and drives ER-PM contact sites formation in order to refill ER-luminal Ca(2+). Recent studies suggest that the ER stress sensor and mediator of the unfolded protein response (UPR) PERK regulates intracellular Ca(2+) fluxes, but the mechanisms remain elusive. Here, using proximity-dependent biotin identification (BioID), we identified the actin-binding protein Filamin A (FLNA) as a key PERK interactor. Cells lacking PERK accumulate F-actin at the cell edges and display reduced ER-PM contacts. Following ER-Ca(2+) store depletion, the PERK-FLNA interaction drives the expansion of ER-PM juxtapositions by regulating F-actin-assisted relocation of the ER-associated tethering proteins Stromal Interaction Molecule 1 (STIM1) and Extended Synaptotagmin-1 (E-Syt1) to the PM. Cytosolic Ca(2+) elevation elicits rapid and UPR-independent PERK dimerization, which enforces PERK-FLNA-mediated ER-PM juxtapositions. Collectively, our data unravel an unprecedented role of PERK in the regulation of ER-PM appositions through the modulation of the actin cytoskeleton.

  18. Design of pathway-preferential estrogens that provide beneficial metabolic and vascular effects without stimulating reproductive tissues

    PubMed Central

    Madak-Erdogan, Zeynep; Kim, Sung-Hoon; Gong, Ping; Zhao, Yiru C.; Zhang, Hui; Chambliss, Ken L.; Carlson, Kathryn E.; Mayne, Christopher G.; Shaul, Philip W.; Korach, Kenneth S.; Katzenellenbogen, John A.; Katzenellenbogen, Benita S.

    2016-01-01

    There is great medical need for estrogens with favorable pharmacological profiles, that support desirable activities for menopausal women such as metabolic and vascular protection but that lack stimulatory activities on the breast and uterus. Here, we report the development of structurally novel estrogens that preferentially activate a subset of estrogen receptor (ER) signaling pathways and result in favorable target tissue-selective activity. Through a process of structural alteration of estrogenic ligands that was designed to preserve their essential chemical and physical features but greatly reduced their binding affinity for ERs, we obtained “Pathway Preferential Estrogens” (PaPEs) which interacted with ERs to activate the extranuclear-initiated signaling pathway preferentially over the nuclear-initiated pathway. PaPEs elicited a pattern of gene regulation and cellular and biological processes that did not stimulate reproductive and mammary tissues or breast cancer cells. However, in ovariectomized mice, PaPEs triggered beneficial responses both in metabolic tissues (adipose tissue and liver) that reduced body weight gain and fat accumulation and in the vasculature that accelerated repair of endothelial damage. This process of designed ligand structure alteration represents a novel approach to develop ligands that shift the balance in ER-mediated extranuclear and nuclear pathways to obtain tissue-selective, non-nuclear pathway-preferential estrogens, which may be beneficial for postmenopausal hormone replacement. The approach may also have broad applicability for other members of the nuclear hormone receptor superfamily. PMID:27221711

  19. FrontiERs: movers and shapers of the higher plant cortical endoplasmic reticulum.

    PubMed

    Sparkes, Imogen; Hawes, Chris; Frigerio, Lorenzo

    2011-12-01

    The endoplasmic reticulum (ER) in higher plants performs many important functions, yet our understanding of how its intricate network shape and dynamics relate to function is very limited. Recent work has begun to unpick key molecular players in the generation of the pleomorphic, highly dynamic ER network structure that pervades the entire cytoplasm. ER movement is acto-myosin dependent. ER shape is dependent on RHD3 (Root Hair Defective 3) and a family of proteins called reticulons. The major challenge that lies ahead is understanding how factors that control ER shape and movement are regulated and how this relates to the numerous functions of the ER.

  20. Flash X-ray testing of ER3400 EAROMS

    NASA Astrophysics Data System (ADS)

    Abare, W. E.; Riley, R. M.; Thygeson, T. L.

    1983-12-01

    Flash X-ray testing of ER3400 MNOS memories demonstrates their memory volatility. Flash X-ray test data is presented for four bias conditions and two write pulse widths. A simple electrical screening technique is described which increases the memory vulnerability threshold. Permanent shifts in access time and memory reference voltage from accumulated doses are discussed.

  1. Control Performance of ER Engine Mount Subjected to Temperature Variations

    NASA Astrophysics Data System (ADS)

    Song, H. J.; Choi, S. B.; Kim, K. S.

    A key function of engine mount of vehicle systems is to support engine mass and isolate noise and vibration from engine disturbance forces. One of attractive candidates to achieve this goal is to utilize a semi-active ER engine mount. By applying this, we can effectively control damping force and hence the noise and vibration by just controlling the intensity of electric field. However, control performance of the engine mount may be very sensitive to temperature variation during engine operation. In this work, we investigate dynamic and control performances of ER engine mount with respect to the temperature variation. In order to undertake this, a flow-mode type of ER engine mount is designed and manufactured. Displacement transmissibility is experimentally evaluated for 1 degree of freedom. The ER engine mount is then incorporated with full-vehicle model in order to investigate vibration control performance. After formulating the governing equation of motion, a semi-active controller is designed. The controller is implemented through a hardware-in-the-loop simulation (HILS), and control responses such as acceleration level at various engine speeds are evaluated in the frequency and time domains.

  2. [Spectroscopic properties of Er3+-doped germanium bismuthate glass].

    PubMed

    Zhang, Yong; Ren, Guo-Zhong; Yang, Qi-Bin; Xu, Chang-Fu; Liu, Yun-Xin; Shang, Zhen-Gang

    2008-05-01

    Er(3+)-Doped Germanium Bismuthate Glass was fabricated and characterized. The absorption spectrum and up-conversion spectrum of glass were studied. The Judd-Oflet intensity parameters omega(t) (t = 2, 4, 6), determined based on Judd-Ofelt theory, were found to be omega2 = 3.35 x 10(-20) cm2, omega4 = 1.34 x 10(-20) cm2, omega6 = 0.67 x 10(-20) cm2. Frequency up-conversion of Er(3+)-doped germanium bismuthate glass has been investigated. The up-conversion mechanisms are discussed under 808 nm and 980 nm excitation. Stimulated emission cross-section of 4I(13/2) --> 4I(15/2) transition was calculated by McCumber theory. Compared to other host glasses, the emission property of Er(3+)-doped germanium bismuthate glasses has advantage over those of silicate, phosphate and germinate glasses. Er(3+)-doped germanium bismuth glasses are promising upconversion optical and optic-communication materials.

  3. OpenER, a Dutch Initiative in Open Educational Resources

    ERIC Educational Resources Information Center

    Schuwer, Robert; Mulder, Fred

    2009-01-01

    Over the period 2006-2008, the Dutch Open Universiteit Nederland conducted an experiment in which Open Educational Resources (OER) were offered in an effort to bridge the gap between informal and formal learning and to establish a new style of entry portal to higher education with no barriers at all. OpenER received considerable attention both in…

  4. Magnetocaloric effect in the metamagnet ErRhSi compound

    NASA Astrophysics Data System (ADS)

    Debnath, J. C.; Nair, Harikrishnan S.; Strydom, André M.; Ramesh Kumar, K.; Wang, Jianli

    2016-12-01

    The magnetocaloric effect is observed in the 1:1:1 compound ErRhSi, which is a metamagnet is reported in this paper. ErRhSi crystallizes in the orthorhombic space group Pnma, adopting the TiNiSi structure type, with lattice parameters a(Å) = 6.7903(5), b(Å) = 4.1881(3), and c(Å) = 7.3847(4). Our magnetic measurements confirm an antiferromagnetic phase transition at TN ≈ 8.5 K, also supported by the specific heat measurement. Crystal field effects of Er3+ are suggested by the inverse magnetic susceptibility data which do not conform to an ideal Curie-Weiss behaviour and also by the total entropy that attains Rln (2) at TN. Although the magnetic hysteresis indicates ErRhSi to be a soft magnet, several clear metamagnetic features are observed at 2 K. Magnetic entropy change ΔSM = - 8.7 J/kg-K is observed at about 9 K with the application of 5 T magnetic field. The corresponding adiabatic temperature change ΔTad is about 4 K. Large magnetocaloric effects suggest that this material is suitable for the low temperature magnetic refrigeration.

  5. Er:YAG laser dentistry in special needs patients

    PubMed Central

    Fornaini, Carlo; Clini, Fabio; Fontana, Matteo; Cella, Luigi; Oppici, Aldo

    2015-01-01

    Objective: Between a quarter and a third of adults with intellectual disability is estimated to have dental anxiety. Unpleasant stimuli, such as the injection of local anaesthesia or the noise and vibration of rotary instruments, may provoke anxiety and subsequent low compliance until the opposition to the treatment. The use of Er:YAG laser in conservative dentistry had a great development in these last years thank to new devices and also to their advantages when compared to the conventional instruments. The aim of this clinical study was to show the advantages of the Er:YAG laser in the conservative treatment of Special Care patients. Methods: Four cases are here described to show the Er:YAG laser use in our Unit on special needs patients. Results and conclusions: Based on the experience gained on conservative laser-assisted treatments performed in a time of 5 years at our Dentistry, Special Needs and Maxillo-Facial Surgery Unit we may affirm that Er:YAG laser may be considered as a good way to improve the cooperation, to reduce anxiety related to rotating instruments and to reach better results with equal or shorter operating times. PMID:26557733

  6. Optimal pumping for eye-safe Er:YAG laser

    NASA Astrophysics Data System (ADS)

    Buchenkov, Vyacheslav A.; Polyakov, Vadim M.; Rodionov, Andrey Y.; Kovalev, Anton V.

    2016-04-01

    We report on theoretical investigation of quasi-three level Er:YAG laser. We propose a numerical model of the laser design with side pump by 1471 nm laser diodes. The model describes the dynamical propagation of the pump in the cavity and the kinetic parameters of the active medium.

  7. Intracellular zinc distribution in mitochondria, ER and the Golgi apparatus.

    PubMed

    Lu, Qiping; Haragopal, Hariprakash; Slepchenko, Kira G; Stork, Christian; Li, Yang V

    2016-01-01

    Zinc (Zn(2+)) is required for numerous cellular functions. As such, the homeostasis and distribution of intracellular zinc can influence cellular metabolism and signaling. However, the exact distribution of free zinc within live cells remains elusive. Previously we showed the release of zinc from thapsigargin/IP3-sensitive endoplasmic reticulum (ER) storage in cortical neurons. In the present study, we investigated if other cellular organelles also contain free chelatable zinc and function as organelle storage for zinc. To identify free zinc within the organelles, live cells were co-stained with Zinpyr-1, a zinc fluorescent dye, and organelle-specific fluorescent dyes (MitoFluor Red 589: mitochondria; ER Tracker Red: endoplasmic reticulum; BODIPY TR ceramide: Golgi apparatus; Syto Red 64: nucleus). We examined organelles that represent potential storing sites for intracellular zinc. We showed that zinc fluorescence staining was co-localized with MitoFluor Red 589, ER Tracker Red, and BODIPY TR ceramide respectively, suggesting the presence of free zinc in mitochondria, endoplasmic reticulum, and the Golgi apparatus. On the other hand, cytosol and nucleus had nearly no detectable zinc fluorescence. It is known that nucleus contains high amount of zinc binding proteins that have high zinc binding affinity. The absence of zinc fluorescence suggests that there is little free zinc in these two regions. It also indicates that the zinc fluorescence detected in mitochondria, ER and Golgi apparatus represents free chelatable zinc. Taken together, our results support that these organelles are potential zinc storing organelles during cellular zinc homeostasis.

  8. L-carnitine attenuates H2O2-induced neuron apoptosis via inhibition of endoplasmic reticulum stress.

    PubMed

    Ye, Junli; Han, Yantao; Chen, Xuehong; Xie, Jing; Liu, Xiaojin; Qiao, Shunhong; Wang, Chunbo

    2014-12-01

    Both oxidative stress and endoplasmic reticulum stress (ER stress) have been linked to pathogenesis of neurodegenerative diseases. Our previous study has shown that L-carnitine may function as an antioxidant to inhibit H2O2-induced oxidative stress in neuroblastoma SH-SY5Y cells. To further explore the neuroprotection of L-carnitine, here we study the effects of L-carnitine on the ER stress response in H2O2-induced SH-SY5Y cell injury. Our results showed that L-carnitine pretreatment could increase cell viability; inhibit apoptosis and ROS accumulation caused by H2O2 or tunicamycin (TM). L-carnitine suppress the endoplasmic reticulum dilation and activation of ER stress-associated proteins including glucose-regulated protein 78 (GRP78), CCAAT/enhancer-binding protein-homologous protein (CHOP), JNK, Bax and Bim induced by H2O2 or TM. In addition, H2O2-induced cell apoptosis and activation of ER stress can also be attenuated by antioxidant N-acetylcysteine (NAC), CHOP siRNA and the inhibitor of ER stress 4-phenylbutyric acid (4-PBA). Taken together, our results demonstrated that H2O2 could trigger both oxidative stress and ER stress in SH-SY5Y cells, and ER stress participated in SH-SY5Y apoptosis mediated by H2O2-induced oxidative stress. CHOP/Bim or JNK/Bim-dependent ER stress signaling pathways maybe related to the neuroprotective effects of L-carnitine against H2O2-induced apoptosis and oxidative injury.

  9. Gene-based analysis of the fibroblast growth factor receptor signaling pathway in relation to breast cancer in African American women: the AMBER consortium.

    PubMed

    Ruiz-Narváez, Edward A; Haddad, Stephen A; Lunetta, Kathryn L; Yao, Song; Bensen, Jeannette T; Sucheston-Campbell, Lara E; Hong, Chi-Chen; Haiman, Christopher A; Olshan, Andrew F; Ambrosone, Christine B; Palmer, Julie R

    2016-01-01

    We conducted gene-based analysis in 26 genes in the FGFR signaling pathway to identify genes carrying genetic variation affecting risk of breast cancer and the specific estrogen receptor (ER) subtypes. Tagging single-nucleotide polymorphisms (SNPs) for each gene were selected and genotyped on a customized Illumina Exome Array. Imputation was carried out using 1000 Genomes haplotypes. The analysis included 3237 SNPs in 3663 breast cancer cases (including 1983 ER-positive, and 1098 ER-negative) and 4687 controls from the African American Breast Cancer Epidemiology and Risk consortium, a collaborative project of four large studies of breast cancer in African American women (Carolina Breast Cancer Study, Black Women's Health Study, Women's Circle of Health Study, and Multiethnic Cohort). We used a multi-locus adaptive joint (AdaJoint) test to determine the association of each gene in the FGFR signaling pathway with overall breast cancer and ER subtypes. The FGF1 gene was significantly associated with risk of ER-negative breast cancer (P = 0.001). The FGFR2 gene was associated with risk of overall breast cancer (P = 0.002) and ER-positive breast cancer (P = 0.002). The FGF1 gene affects risk of ER-negative breast cancer in African American women. We confirmed the association of the FGFR2 gene with risk of overall and ER-positive breast cancer. These results highlight the importance of the FGFR signaling pathway in the pathogenesis of breast cancer, and suggest that different genes in the same pathway may be associated with different ER breast cancer subtypes.

  10. Gene-based analysis of the fibroblast growth factor receptor signaling pathway in relation to breast cancer in African American women: the AMBER consortium

    PubMed Central

    Ruiz-Narváez, Edward A.; Haddad, Stephen A.; Lunetta, Kathryn L.; Yao, Song; Bensen, Jeannette T.; Sucheston-Campbell, Lara E.; Hong, Chi-Chen; Haiman, Christopher A.; Olshan, Andrew F.; Ambrosone, Christine B.; Palmer, Julie R.

    2016-01-01

    Purpose We conducted gene-based analysis in 26 genes in the FGFR signaling pathway to identify genes carrying genetic variation affecting risk of breast cancer and the specific estrogen receptor (ER) subtypes. Methods Tagging single nucleotide polymorphisms (SNPs) for each gene were selected and genotyped on a customized Illumina Exome Array. Imputation was carried out using 1000 Genomes haplotypes. The analysis included 3,237 SNPs in 3,663 breast cancer cases (including 1,983 ER positive, and 1,098 ER-negative and 4,687 controls from the African American Breast Cancer Epidemiology and Risk consortium, a collaborative project of four large studies of breast cancer in African American women (Carolina Breast Cancer Study, Black Women's Health Study, Women's Circle of Health Study, and Multiethnic Cohort). We used a multi-locus adaptive joint (AdaJoint) test to determine the association of each gene in the FGFR signaling pathway with overall breast cancer and ER subtypes. Results The FGF1 gene was significantly associated with risk of ER negative breast cancer (P = 0.001). The FGFR2 gene was associated with risk of overall breast cancer (P = 0.002) and ER positive breast cancer (P = 0.002). Conclusions The FGF1 gene affects risk of ER negative breast cancer in African American women. We confirmed the association of the FGFR2 gene with risk of overall and ER positive breast cancer. These results highlight the importance of the FGFR signaling pathway in the pathogenesis of breast cancer, and suggest that different genes in the same pathway may be associated with different ER breast cancer subtypes. PMID:26743380

  11. Multiple pathways influence mitochondrial inheritance in budding yeast.

    PubMed

    Frederick, Rebecca L; Okamoto, Koji; Shaw, Janet M

    2008-02-01

    Yeast mitochondria form a branched tubular network. Mitochondrial inheritance is tightly coupled with bud emergence, ensuring that daughter cells receive mitochondria from mother cells during division. Proteins reported to influence mitochondrial inheritance include the mitochondrial rho (Miro) GTPase Gem1p, Mmr1p, and Ypt11p. A synthetic genetic array (SGA) screen revealed interactions between gem1Delta and deletions of genes that affect mitochondrial function or inheritance, including mmr1Delta. Synthetic sickness of gem1Delta mmr1Delta double mutants correlated with defective mitochondrial inheritance by large buds. Additional studies demonstrated that GEM1, MMR1, and YPT11 each contribute to mitochondrial inheritance. Mitochondrial accumulation in buds caused by overexpression of either Mmr1p or Ypt11p did not depend on Gem1p, indicating these three proteins function independently. Physical linkage of mitochondria with the endoplasmic reticulum (ER) has led to speculation that distribution of these two organelles is coordinated. We show that yeast mitochondrial inheritance is not required for inheritance or spreading of cortical ER in the bud. Moreover, Ypt11p overexpression, but not Mmr1p overexpression, caused ER accumulation in the bud, revealing a potential role for Ypt11p in ER distribution. This study demonstrates that multiple pathways influence mitochondrial inheritance in yeast and that Miro GTPases have conserved roles in mitochondrial distribution.

  12. The mammalian target of rapamycin complex 1 (mTORC1) in breast cancer: the impact of oestrogen receptor and HER2 pathways.

    PubMed

    Jerjees, Dena A; Negm, Ola H; Alabdullah, M Layth; Mirza, Sameer; Alkaabi, Methaq; Hameed, Mohamed R; Abduljabbar, Rezvan; Muftah, Abir; Nolan, Chris C; Green, Andrew R; Tighe, Patrick J; Band, Vimla; Ellis, Ian O; Rakha, Emad A

    2015-02-01

    The mammalian target of rapamycin complex 1 (mTORC1) is a downstream of the PI3K/Akt pathway which affects cancer development. mTORC1 has many downstream signalling effectors that can enhance different cellular responses. This study aims to investigate the expression of mTORC1 in breast cancer (BC) and correlate it with key clinicopathological and molecular features of BC especially to proteins related to oestrogen receptor (ER) and HER2 pathways in different BC classes. Moreover, mTORC1 expression was assessed in 6 BC cell lines including ER+ and ER- cell lines with and without HER2 transfection. Immunohistochemistry was used to assess the expression of phospho (p) mTORC1 in a large (n = 1300) annotated BC series prepared as tissue microarray. Reverse phase protein array (RPPA) was used to assess its expression in the different BC cell lines. The expression of p-mTORC1 was cytoplasmic with moderate/high expression noted in 44 % of BC. p-mTORC1 expression was associated with clinicopathological variables characteristic of good prognosis. Positive correlation with ER, ER-related proteins AKT, PI3K and luminal differentiation markers were observed in the whole series and in the ER+HER2- subgroup. Association with HER2 was mainly observed in the ER-negative class. RPPA indicated that p-mTORC1 expression was mainly related to ER expression and with better outcome in the Akt positive tumours. p-mTORC1 is associated with good prognostic features. Its expression is related to ER and ER related proteins in addition to AKT and PI3K. Its relation with HER2 expression is mainly seen in the absence of ER expression.

  13. Decreased ER-associated degradation of α-TCR induced by Grp78 depletion with the SubAB cytotoxin

    PubMed Central

    Lass, Agnieszka; Kujawa, Marek; McConnell, Elizabeth; Paton, Adrienne W.; Paton, James C.; Wójcik, Cezary

    2008-01-01

    HeLa cells stably expressing the α chain of T-cell receptor (αTCR), a model substrate of ERAD (ER-associated degradation), were used to analyze the effects of BiP/Grp78 depletion by the SubAB cytotoxin. SubAB induced XBP1 splicing, followed by JNK phosphorylation, eIF2α phosphorylation, upregulation of ATF3/4 and partial ATF6 cleavage. Other markers of ER stress, including elements of ER-associated degradation (ERAD) pathway, as well as markers of cytoplasmic stress, were not induced. SubAB treatment decreased absolute levels of αTCR, which was caused by inhibition of protein synthesis. At the same time, the half-life of αTCR was extended almost fourfold from 70 min to 210 min, suggesting that BiP normally facilitates ERAD. Depletion ofp97/VCP partially rescued SubAB-induced depletion of αTCR, confirming the role of VCP in ERAD of αTCR. It therefore appears that ERAD of αTCR is driven by at least two different ATP-ase systems located at two sides of the ER membrane, BiP located on the lumenal side, while p97/VCP on the cytoplasmic side. While SubAB altered cell morphology by inducing cytoplasm vacuolization and accumulation of lipid droplets, caspase activation was partial and subsided after prolonged incubation. Expression of CHOP/GADD153 occurred only after prolonged incubation and was not associated with apoptosis. PMID:18611445

  14. ER stress related factor ATF6 and caspase-12 trigger apoptosis in neonatal hypoxic-ischemic encephalopathy

    PubMed Central

    Liu, Luran; Liu, Chang; Lu, Yuting; Liu, Lina; Jiang, Yan

    2015-01-01

    The specific and available markers proteins of neonatal hypoxic-ischemic encephalopathy (HIE) injury are correlated with disease severity and the disability in childhood. Exploring the mechanism of HIE is very helpful to the targeted therapeutic approach in clinical. This study aims to explore the cell death-related proteins or biomarkers that plays roles in the HIE injury. In this study, 15 patients were included the 487 autopsies patients performed at the Department of Pathology. The lactate dehydrogenase (LDH) assay was used to detect the cell viability of NGF-differentiated PC12 cell. TUNEL assay was employed to examine the apoptotic cells in embedded slides samples. Three ER stress-related protein, including ATF6, p-Perk and IRE-1 were investigated using Western blot assay for the ER stress examination. The apoptosis associated caspase-12 and CHOP protein were detected by Western blot. The results indicated that LDH activity of living cells during hypoxia was significantly enhanced to 45% and 64% after 8 hours and 24 hours. The TUNEL results showed that plenty of the PC12 cells became the positive staining cells when treated with 0.1% O2 hypoxia. ER stress UPR pathway protein, cleaved ATF6, was increased significantly when treated with 0.1% O2 compared with the cells treated with 20% O2. Furthermore, the caspase 12 activation was triggered when the cells treated with the 0.1% O2. In conclusion, apoptosis is served as an important factor that triggers the HIE brain injury through cleaving the ATF6 and caspase-12 ER stress-related protein. PMID:26261584

  15. 184AA3: A Xenograft Model of ER+ Breast Adenocarcinoma

    PubMed Central

    Hines, William C.; Kuhn, Irene; Thi, Kate; Chu, Berbie; Stanford-Moore, Gaelen; Sampayo, Rocío; Garbe, James C.; Stampfer, Martha; Borowsky, Alexander D.; Bissell, Mina

    2015-01-01

    Purpose Despite the prevalence and significant morbidity resulting from estrogen receptor positive (ER+) breast adenocarcinomas, there are only a few models of this cancer subtype available for drug development, and arguably none for studying etiology. Those models that do exist have questionable clinical relevance. Methods Given our goal of developing luminal models, we focused on six cell lines derived by minimal mutagenesis from normal human breast cells, and asked if any could generate clinically relevant xenografts, which we then extensively characterized. Results Xenografts of one cell line, 184AA3, consistently formed ER+ adenocarcinomas that had a high proliferative rate and other features consistent with “luminal B” intrinsic subtype. Squamous and spindle cell/mesenchymal differentiation was absent, in stark contrast to other cell lines that we examined or others have reported. We explored intratumoral heterogeneity produced by 184AA3 by immunophenotyping xenograft tumors and cultured cells, and characterized marker expression by immunofluorescence and flow cytometry. A CD44High subpopulation was discovered, yet their tumor forming ability was far less than CD44Low cells. Single cell cloning revealed the phenotypic plasticity of 184AA3, consistent with the intratumoral heterogeneity observed in xenografts. Characterization of ER expression in cultures revealed ER protein and signaling is intact, yet when estrogen was depleted in culture, and in vivo, it did not impact cell or tumor growth, analogous to therapeutically resistant ER+ cancers. Conclusions This model is appropriate for studies of the etiology of ovarian hormone independent adenocarcinomas, for identification of therapeutic targets, predictive testing and drug development. PMID:26661596

  16. 17β-Estradiol inhibits ER stress-induced apoptosis through promotion of TFII-I-dependent Grp78 induction in osteoblasts.

    PubMed

    Guo, Yun-Shan; Sun, Zhen; Ma, Jie; Cui, Wei; Gao, Bo; Zhang, Hong-Yang; Han, Yue-Hu; Hu, Hui-Min; Wang, Long; Fan, Jing; Yang, Liu; Tang, Juan; Luo, Zhuo-Jing

    2014-08-01

    Although many studies have suggested that estrogen prevents postmenopausal bone loss partially due to its anti-apoptosis effects in osteoblasts, the underlying mechanism has not been fully elucidated. In the present study, we found that 17β-estradiol (17β-E₂), one of the primary estrogens, inhibited endoplasmic reticulum (ER) stress-induced apoptosis in MC3T3-E1 cells and primary osteoblasts. Interestingly, 17β-E₂-promoted Grp78 induction, but not CHOP induction in response to ER stress. We further confirmed that Grp78-specific siRNA reversed the inhibition of 17β-E₂ on ER stress-induced apoptosis by activating caspase-12 and caspase-3. Moreover, we found that 17β-E₂ markedly increased the phosphorylated TFII-I levels and nuclear localization of TFII-I in ER stress conditions. 17β-E₂ stimulated Grp78 promoter activity in a dose-dependent manner in the presence of TFII-I and enhanced the binding of TFII-I to the Grp78 promoter. In addition, 17β-E₂ notably increased phosphorylated ERK1/2 levels and Ras kinase activity in MC3T3-E1 cells. The ERK1/2 activity-specific inhibitor U0126 remarkably blocked 17β-E₂-induced TFII-I phosphorylation and Grp78 expression in response to ER stress. Together, 17β-E₂ protected MC3T3-E1 cells against ER stress-induced apoptosis by promoting Ras-ERK1/2-TFII-I signaling pathway-dependent Grp78 induction.

  17. Automated identification of pathways from quantitative genetic interaction data

    PubMed Central

    Battle, Alexis; Jonikas, Martin C; Walter, Peter; Weissman, Jonathan S; Koller, Daphne

    2010-01-01

    High-throughput quantitative genetic interaction (GI) measurements provide detailed information regarding the structure of the underlying biological pathways by reporting on functional dependencies between genes. However, the analytical tools for fully exploiting such information lag behind the ability to collect these data. We present a novel Bayesian learning method that uses quantitative phenotypes of double knockout organisms to automatically reconstruct detailed pathway structures. We applied our method to a recent data set that measures GIs for endoplasmic reticulum (ER) genes, using the unfolded protein response as a quantitative phenotype. The results provided reconstructions of known functional pathways including N-linked glycosylation and ER-associated protein degradation. It also contained novel relationships, such as the placement of SGT2 in the tail-anchored biogenesis pathway, a finding that we experimentally validated. Our approach should be readily applicable to the next generation of quantitative GI data sets, as assays become available for additional phenotypes and eventually higher-level organisms. PMID:20531408

  18. Functional characterization of estrogen receptor subtypes, ER{alpha} and ER{beta}, mediating vitellogenin production in the liver of rainbow trout

    SciTech Connect

    Leanos-Castaneda, Olga Kraak, Glen van der

    2007-10-15

    The estrogen-dependent process of vitellogenesis is a key function on oviparous fish reproduction and it has been widely used as an indicator of xenoestrogen exposure. The two estrogen receptor (ER) subtypes, ER{alpha} and ER{beta}, are often co-expressed in the liver of fish. The relative contribution of each ER subtype to modulate vitellogenin production by hepatocytes was studied using selected compounds known to preferentially interact with specific ER subtypes: propyl-pyrazole-triol (PPT) an ER{alpha} selective agonist, methyl-piperidino-pyrazole (MPP) an ER{alpha} selective antagonist, and diarylpropionitrile (DPN) an ER{beta} selective agonist. First, the relative binding affinity of the test compounds to estradiol for rainbow trout hepatic nuclear ER was determined using a competitive ligand binding assay. All the test ligands achieved complete displacement of specific [{sup 3}H]-estradiol binding from the nuclear ER extract. This indicates that the test ligands have the potential to modify the ER function in the rainbow trout liver. Secondly, the ability of the test compounds to induce or inhibit vitellogenin production by primary cultures of rainbow trout hepatocytes was studied. Estradiol and DPN were the only compounds that induced a dose-dependent increase on vitellogenin synthesis. The lack of vitellogenin induction by PPT indicates that ER{alpha} could not have a role on this reproductive process whereas the ability of DPN to induce vitellogenin production supports the participation of ER{beta}. In addition, this hypothesis is reinforced by the results obtained from MPP plus estradiol. On one hand, the absence of suppressive activity of MPP in the estradiol-induced vitellogenin production does not support the participation of ER{alpha}. On the other hand, once blocked ER{alpha} with MPP, the only manifestation of agonist activity of estradiol would be achieved via ER{beta}. In conclusion, the present results indicate that vitellogenin production is

  19. [Spectroscopic analysis of Er3+ in Er3+ /Yb3+ co-doped LiNbO3 crystal].

    PubMed

    Wang, Dun-Chun; Zhang, De-Long; Cui, Yu-Ming; Chen, Cai-He

    2005-12-01

    At room temperature, alpha-polarized absorption spectra of as-grown and annealed Er3+/Yb3+ co-doped, Z-cut LiNbO3 single crystals, grown by using Czochralski method, were measured in the wavelength range of 300-1 650 nm. The spectroscopic properties of Er3+ were analysed by using Judd-Ofelt theory. The experimental values of the electron transition strengths of several major transitions from the ground state to excited-state manifolds were evaluated from the measured integrated absorption coefficients of Er3+. The Judd-Ofelt parameters were determined by using least square method. According to the fitted Judd-Ofelt parameters, the spontaneous emission rates, the fluorescence branch ratios from the excited-state manifolds J to the lower-lying manifolds J', as well as the radiative lifetimes of the excited states were numerically calculated. In addition, Yb3+ co-doping and thermal anneal effects on the spectroscopic properties of Er3+ were also considered in this work.

  20. Comparative life cycle assessment of three biohydrogen pathways.

    PubMed

    Djomo, Sylvestre Njakou; Blumberga, Dagnija

    2011-02-01

    A life cycle assessment was performed to quantify and compare the energetic and environmental performances of hydrogen from wheat straw (WS-H(2)), sweet sorghum stalk (SSS-H(2)), and steam potato peels (SPP-H(2)). Inventory data were derived from a pilot plant. Impacts were assessed using the impact 2002+ method. When co-product was not considered, the greenhouse gas (GHG) emissions were 5.60 kg CO(2eq) kg(-1) H(2) for WS-H(2), 5.32 kg CO(2eq) kg(-1) H(2) for SSS-H(2), and 5.18 kg CO(2eq) kg(-1) H(2) for SPP-H(2). BioH(2) pathways reduced GHG emissions by 52-56% compared to diesel and by 54-57% compared to steam methane reforming production of H(2). The energy ratios (ER) were also comparable: 1.08 for WS-H(2), 1.14 for SSS-H(2) and 1.17 for SPP-H(2). A shift from SPP-H(2) to WS-H(2) would therefore not affect the ER and GHG emissions of these BioH(2) pathways. When co-product was considered, a shift from SPP-H(2) to WS-H(2) or SSS-H(2) decreased the ER, while increasing the GHG emissions significantly. Co-product yield should be considered when selecting BioH(2) feedstocks.

  1. ER-mediated control for abundance, quality, and signaling of transmembrane immune receptors in plants

    PubMed Central

    Tintor, Nico; Saijo, Yusuke

    2014-01-01

    Plants recognize a wide range of microbes with cell-surface and intracellular immune receptors. Transmembrane pattern recognition receptors (PRRs) initiate immune responses upon recognition of cognate ligands characteristic of microbes or aberrant cellular states, designated microbe-associated molecular patterns or danger-associated molecular patterns (DAMPs), respectively.Pattern-triggered immunity provides a first line of defense that restricts the invasion and propagation of both adapted and non-adapted pathogens. Receptor kinases (RKs) and receptor-like proteins (RLPs) with an extracellular leucine-rich repeat or lysine-motif (LysM) domain are extensively used as PRRs. The correct folding of the extracellular domain of these receptors is under quality control (QC) in the endoplasmic reticulum (ER), which thus provides a critical step in plant immunity. Genetic and structural insight suggests that ERQC regulates not only the abundance and quality of transmembrane receptors but also affects signal sorting between multi-branched pathways downstream of the receptor. However, ERQC dysfunction can also positively stimulate plant immunity, possibly through cell death and DAMP signaling pathways. PMID:24616730

  2. The Xbp1s/GalE axis links ER stress to postprandial hepatic metabolism.

    PubMed

    Deng, Yingfeng; Wang, Zhao V; Tao, Caroline; Gao, Ningguo; Holland, William L; Ferdous, Anwarul; Repa, Joyce J; Liang, Guosheng; Ye, Jin; Lehrman, Mark A; Hill, Joseph A; Horton, Jay D; Scherer, Philipp E

    2013-01-01

    Postprandially, the liver experiences an extensive metabolic reprogramming that is required for the switch from glucose production to glucose assimilation. Upon refeeding, the unfolded protein response (UPR) is rapidly, though only transiently, activated. Activation of the UPR results in a cessation of protein translation, increased chaperone expression, and increased ER-mediated protein degradation, but it is not clear how the UPR is involved in the postprandial switch to alternate fuel sources. Activation of the inositol-requiring enzyme 1 (IRE1) branch of the UPR signaling pathway triggers expression of the transcription factor Xbp1s. Using a mouse model with liver-specific inducible Xbp1s expression, we demonstrate that Xbp1s is sufficient to provoke a metabolic switch characteristic of the postprandial state, even in the absence of caloric influx. Mechanistically, we identified UDP-galactose-4-epimerase (GalE) as a direct transcriptional target of Xbp1s and as the key mediator of this effect. Our results provide evidence that the Xbp1s/GalE pathway functions as a novel regulatory nexus connecting the UPR to the characteristic postprandial metabolic changes in hepatocytes.

  3. PTEN insufficiency modulates ER+ breast cancer cell cycle progression and increases cell growth in vitro and in vivo.

    PubMed

    Chiang, Kun-Chun; Chen, Huang-Yang; Hsu, Shu-Yuan; Pang, Jong-Hwei S; Wang, Shang-Yu; Hsu, Jun-Te; Yeh, Ta-Sen; Chen, Li-Wei; Kuo, Sheng-Fong; Sun, Chi-Chin; Lee, Jim-Ming; Yeh, Chun-Nan; Juang, Horng-Heng

    2015-01-01

    Phosphatase and tensin homolog (PTEN), a well-known tumor suppressor gene and frequently mutated or lost in breast cancer, possesses the negative regulation function over the PI3K/Akt/mTOR pathway. PTEN insufficiency has been associated with advanced breast cancer and poor prognosis of breast cancer patients. Recently, target therapies aimed at PI3K/Akt/mTOR pathway to treat breast cancer have got popularity. However, the exact effect of PTEN on breast cancer cells is still not well understood. This study demonstrated that PTEN knockdown in MCF-7 cells strengthened the downstream gene expressions, including p-Akt, p-ERK1/2, p-mTOR, p-p70s6k, and p-GSK3β. PTEN knockdown MCF-7 cells had increased cell growth and Ki-67 expression. Further Western blot demonstrated that p27 was repressed obviously with p21 slightly inhibited and CDK1, 2, 4, 6, cyclin A, and Cdc25C were upregulated in MCF-7 PTEN knockdown cells, leading to the higher growth rate. More importantly, PTEN knockdown MCF-7 cells had higher tumorigenesis and tumor growth in vivo. From our current work, we provided more detailed PTEN-mediated mechanisms to stimulate ER+ breast cancer cell growth. Our result may pave the way for further target therapy development used alone or in combination with other drugs for ER+ breast cancer with PTEN insufficiency.

  4. PTEN insufficiency modulates ER+ breast cancer cell cycle progression and increases cell growth in vitro and in vivo

    PubMed Central

    Chiang, Kun-Chun; Chen, Huang-Yang; Hsu, Shu-Yuan; Pang, Jong-Hwei S; Wang, Shang-Yu; Hsu, Jun-Te; Yeh, Ta-Sen; Chen, Li-Wei; Kuo, Sheng-Fong; Sun, Chi-Chin; Lee, Jim-Ming; Yeh, Chun-Nan; Juang, Horng-Heng

    2015-01-01

    Phosphatase and tensin homolog (PTEN), a well-known tumor suppressor gene and frequently mutated or lost in breast cancer, possesses the negative regulation function over the PI3K/Akt/mTOR pathway. PTEN insufficiency has been associated with advanced breast cancer and poor prognosis of breast cancer patients. Recently, target therapies aimed at PI3K/Akt/mTOR pathway to treat breast cancer have got popularity. However, the exact effect of PTEN on breast cancer cells is still not well understood. This study demonstrated that PTEN knockdown in MCF-7 cells strengthened the downstream gene expressions, including p-Akt, p-ERK1/2, p-mTOR, p-p70s6k, and p-GSK3β. PTEN knockdown MCF-7 cells had increased cell growth and Ki-67 expression. Further Western blot demonstrated that p27 was repressed obviously with p21 slightly inhibited and CDK1, 2, 4, 6, cyclin A, and Cdc25C were upregulated in MCF-7 PTEN knockdown cells, leading to the higher growth rate. More importantly, PTEN knockdown MCF-7 cells had higher tumorigenesis and tumor growth in vivo. From our current work, we provided more detailed PTEN-mediated mechanisms to stimulate ER+ breast cancer cell growth. Our result may pave the way for further target therapy development used alone or in combination with other drugs for ER+ breast cancer with PTEN insufficiency. PMID:26316702

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

    SciTech Connect

    Katoh, Hironori; Fujita, Keiko; Takuhara, Yuki; Ogawa, Atsushi; Suzuki, Shunji

    2011-02-18

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

  6. SEAP activity serves for demonstrating ER stress induction by glucolipotoxicity as well as testing ER stress inhibitory potential of therapeutic agents.

    PubMed

    Lenin, Raji; Mohan, Viswanathan; Balasubramanyam, Muthuswamy

    2015-06-01

    Endoplasmic reticulum (ER) stress is emerging as a unifying paradigm and one of the underlying mechanisms in the genesis of diabetes and its complications. While this has prompted the development of ER stress inhibitors, there is a limitation in monitoring of ER stress in vitro and in vivo by reliable methodologies. We validated the secreted alkaline phosphatase (SEAP) activity as a surrogate marker of ER stress in mouse β-TC6 cells exposed to glucolipotoxicity or tunicamycin and studied insulin secretion along with alterations in ER stress markers. SEAP activity assay was measured using the Great EscAPe SEAP kit, insulin levels were determined by Mercodia reagents and mRNA expression of ER stress markers was quantified by real-time PCR. SEAP activity in β-cells was significantly decreased (indicating increased ER stress) on exposure either to glucolipotoxicity or tunicamycin. This was accompanied by an increased mRNA expression of ER stress markers (GRP-78, PERK, IRE1α, ATF6, XBP-1, and CHOP) and decreased insulin secretion. Treating the cells with phenylbutyric acid normalized SEAP activity, decreased mRNA expression of ER stress markers and improved insulin secretion. Interestingly, cells exposed to different classes of anti-diabetes agents or compounds such as resveratrol resisted ER stress. Methylglyoxal also induces ER stress and this was counteracted by aminoguanidine. Out study demonstrates SEAP activity as a novel ER stress monitoring assay to investigate the therapeutic value of agents with ER stress inhibitory potential. Future studies should focus on the exercise of adopting this reporter assay for high-throughput screening mode of drug discovery.

  7. Pathway Analysis Revealed Potential Diverse Health Impacts of Flavonoids that Bind Estrogen Receptors

    PubMed Central

    Ye, Hao; Ng, Hui Wen; Sakkiah, Sugunadevi; Ge, Weigong; Perkins, Roger; Tong, Weida; Hong, Huixiao

    2016-01-01

    Flavonoids are frequently used as dietary supplements in the absence of research evidence regarding health benefits or toxicity. Furthermore, ingested doses could far exceed those received from diet in the course of normal living. Some flavonoids exhibit binding to estrogen receptors (ERs) with consequential vigilance by regulatory authorities at the U.S. EPA and FDA. Regulatory authorities must consider both beneficial claims and potential adverse effects, warranting the increases in research that has spanned almost two decades. Here, we report pathway enrichment of 14 targets from the Comparative Toxicogenomics Database (CTD) and the Herbal Ingredients’ Targets (HIT) database for 22 flavonoids that bind ERs. The selected flavonoids are confirmed ER binders from our earlier studies, and were here found in mainly involved in three types of biological processes, ER regulation, estrogen metabolism and synthesis, and apoptosis. Besides cancers, we conjecture that the flavonoids may affect several diseases via apoptosis pathways. Diseases such as amyotrophic lateral sclerosis, viral myocarditis and non-alcoholic fatty liver disease could be implicated. More generally, apoptosis processes may be importantly evolved biological functions of flavonoids that bind ERs and high dose ingestion of those flavonoids could adversely disrupt the cellular apoptosis process. PMID:27023590

  8. Protein–Protein and Protein–Membrane Associations in the Lignin Pathway[W][OA

    PubMed Central

    Bassard, Jean-Etienne; Richert, Ludovic; Geerinck, Jan; Renault, Hugues; Duval, Frédéric; Ullmann, Pascaline; Schmitt, Martine; Meyer, Etienne; Mutterer, Jerôme; Boerjan, Wout; De Jaeger, Geert; Mely, Yves; Goossens, Alain; Werck-Reichhart, Danièle

    2012-01-01

    Supramolecular organization of enzymes is proposed to orchestrate metabolic complexity and help channel intermediates in different pathways. Phenylpropanoid metabolism has to direct up to 30% of the carbon fixed by plants to the biosynthesis of lignin precursors. Effective coupling of the enzymes in the pathway thus seems to be required. Subcellular localization, mobility, protein–protein, and protein–membrane interactions of four consecutive enzymes around the main branch point leading to lignin precursors was investigated in leaf tissues of Nicotiana benthamiana and cells of Arabidopsis thaliana. CYP73A5 and CYP98A3, the two Arabidopsis cytochrome P450s (P450s) catalyzing para- and meta-hydroxylations of the phenolic ring of monolignols were found to colocalize in the endoplasmic reticulum (ER) and to form homo- and heteromers. They moved along with the fast remodeling plant ER, but their lateral diffusion on the ER surface was restricted, likely due to association with other ER proteins. The connecting soluble enzyme hydroxycinnamoyltransferase (HCT), was found partially associated with the ER. Both HCT and the 4-coumaroyl-CoA ligase relocalized closer to the membrane upon P450 expression. Fluorescence lifetime imaging microscopy supports P450 colocalization and interaction with the soluble proteins, enhanced by the expression of the partner proteins. Protein relocalization was further enhanced in tissues undergoing wound repair. CYP98A3 was the most effective in driving protein association. PMID:23175744

  9. 78 FR 4857 - Agency Information Collection Activities: Petition for Amerasian, Widow(er), or Special Immigrant...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-23

    ... Amerasian, Widow(er), or Special Immigrant, Form I-360; Revision of a Currently Approved Collection ACTION.../Collection: Petition for Amerasian, Widow(er), or Special Immigrant (3) Agency form number, if any, and...

  10. cSrc and Her2 Signaling Pathways Cooperate with Estrogen to Promote ER Phosphorylation, Ubiquitination and Proteolysis in ER Negative Breast Cancers

    DTIC Science & Technology

    2007-03-01

    the estrogen receptor through phosphorylation by mitogen- activated protein kinase. Science 270:1491-1494. 31. Ignar -Trowbridge,D.M., Nelson,K.G...phosphorylation. Hormonal dependence and consequence on specific DNA binding. J Biol Chem 1992;267:7263–8. 54. Ignar -Trowbridge DM, Teng CT, Ross KA

  11. Excitation and De-Excitation Mechanisms of ER - Gallium Arsenide and Aluminum Gallium Arsenide

    NASA Astrophysics Data System (ADS)

    Elsaesser, David William

    Electrical and optical characterization have been performed on GaAs and Al_{rm x}Ga_{rm 1-x} As samples doped with Er either by ion implantation and during Molecular Beam Epitaxial (MBE) growth. The electrical techniques of Deep Level Transient Spectroscopy (DLTS) and Temperature-Dependent Hall Effect (TDH) indicated that Er primarily formed two electrically active centers in both materials. The first center gave rise to a hole trap at E_{rm v} + 35 meV, which was thought to be due to Er substituting for a Ga atom (Er_{rm Ga}) and giving rise to an isoelectronic impurity potential. The second center also gave rise to a hole trap at approximately E_{rm v} + 360 meV, and was attributed to an Er atom occupying an interstitial position (Er_{rm i}). Annealing studies performed on Er-implanted GaAs indicated that the Er_{rm Ga} center preferentially formed at higher annealing temperatures (> 850^circC), with the Er_{rm i} reaching a maximum concentration at an annealing temperature of around 750^circC. Additionally, optical characterization performed by Photoluminescence (PL) measurements showed that the Er_{ rm i} center gave much stronger Er-related emissions due to the transition ^4I _{13/2} to ^4 I_{15/2} in the unfilled Er^{3+}-4f shell than was observed for 4f-emissions associated with the Er_{rm Ga} center. Mechanisms for the excitation and de-excitation of the Er-4f shell in GaAs, consistent with all experimental observations, were proposed. DLTS measurements also detected the presence of a large concentration of Ga-antisite (Ga_ {rm As}) defects as well as As-interstitial (As_{rm i}) defects. Based upon reports of Er^{3+} -4f emissions from four distinct Er-centers, two other likely Er-centers were proposed, Er_{rm Ga}-Ga_{rm As} and Er_{rm Ga} -As_{rm i}. Finally, electrical and optical characterization of Er-doped MBE -grown Al_{0.5}Ga _{rm 0.5}As indicated that the solubility limit of Er in this material was possibly as high as 2 times 10^ {19} cm^{-3}, as

  12. Lifespan Extension Conferred by Endoplasmic Reticulum Secretory Pathway Deficiency Requires Induction of the Unfolded Protein Response

    PubMed Central

    Labunskyy, Vyacheslav M.; Gerashchenko, Maxim V.; Delaney, Joe R.; Kaya, Alaattin; Kennedy, Brian K.; Kaeberlein, Matt; Gladyshev, Vadim N.

    2014-01-01

    Cells respond to accumulation of misfolded proteins in the endoplasmic reticulum (ER) by activating the unfolded protein response (UPR) signaling pathway. The UPR restores ER homeostasis by degrading misfolded proteins, inhibiting translation, and increasing expression of chaperones that enhance ER protein folding capacity. Although ER stress and protein aggregation have been implicated in aging, the role of UPR signaling in regulating lifespan remains unknown. Here we show that deletion of several UPR target genes significantly increases replicative lifespan in yeast. This extended lifespan depends on a functional ER stress sensor protein, Ire1p, and is associated with constitutive activation of upstream UPR signaling. We applied ribosome profiling coupled with next generation sequencing to quantitatively examine translational changes associated with increased UPR activity and identified a set of stress response factors up-regulated in the long-lived mutants. Besides known UPR targets, we uncovered up-regulation of components of the cell wall and genes involved in cell wall biogenesis that confer resistance to multiple stresses. These findings demonstrate that the UPR is an important determinant of lifespan that governs ER stress and identify a signaling network that couples stress resistance to longevity. PMID:24391512

  13. Glucosidase II and MRH-domain containing proteins in the secretory pathway

    PubMed Central

    D’Alessio, Cecilia; Dahms, Nancy M.

    2015-01-01

    N -glycosylation in the endoplasmic reticulum (ER) consists of the transfer of a pre-assembled glycan conserved among species (Glc3Man9GlcNAc2) from a lipid donor to a consensus sequence within a nascent protein that is entering the ER. The protein-linked glycans are then processed by glycosidases and glycosyltransferases in the ER producing specific structures that serve as signalling molecules for the fate of the folding glycoprotein: to stay in the ER during the folding process, to be retrotranslocated to the cytosol for proteasomal degradation if irreversibly misfolded, or to pursue transit through the secretory pathway as a mature glycoprotein. In the ER, each glycan signalling structure is recognized by a specific lectin. A domain similar to that of the mannose 6-phosphate receptors (MPRs) has been identified in several proteins of the secretory pathway. These include the beta subunit of glucosidase II (GII), a key enzyme in the early processing of the transferred glycan that removes middle and innermost glucoses and is involved in quality control of glycoprotein folding in the ER (QC), the lectins OS-9 and XTP3-B, proteins involved in the delivery of ER misfolded proteins to degradation (ERAD), the gamma subunit of the Golgi GlcNAc-1-phosphotransferase, an enzyme involved in generating the mannose 6-phosphate (M6P) signal for sorting acidic hydrolases to lysosomes, and finally the MPRs that deliver those hydrolytic enzymes to the lysosome. Each of the MRH-containing proteins recognizes a different signalling N-glycan structure. Three-dimensional structures of some of the MRH domains have been solved, providing the basis to understand recognition mechanisms. PMID:25692846

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

    PubMed

    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.

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

    PubMed Central

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

    2017-01-01

    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

  16. Structurally similar estradiol analogs uniquely alter the regulation of intracellular signaling pathways.

    PubMed

    Yarger, James G; Babine, Robert E; Bittner, Michael; Shanle, Erin; Xu, Wei; Hershberger, Pamela; Nye, Steven H

    2013-02-01

    Ligand structure can affect the activation of nuclear receptors, such as estrogen receptors (ERs), and their control of signaling pathways for cellular responses including death and differentiation. We hypothesized that distinct biological functions of similar estradiol (E(2)) analogs could be identified by integrating gene expression patterns obtained from human tumor cell lines with receptor binding and functional data for the purpose of developing compounds for treatment of a variety of diseases. We compared the estrogen receptor subtype selectivity and impact on signaling pathways for three distinct, but structurally similar, analogs of E(2). Modifications in the core structure of E(2) led to pronounced changes in subtype selectivity for estrogen receptors, ER-α or ER-β, along with varying degrees of ER dimerization and activation. While all three E(2) analogs are predominantly ER-β agonists, the cell growth inhibitory activity commonly associated with this class of compounds was detected for only two of the analogs and might be explained by a ligand-specific pattern of gene transcription. Microarray studies using three different human tumor cell lines demonstrated that the analogs distinctly affect the transcription of genes in signaling pathways for chromosome replication, cell death, and oligodendrocyte progenitor cell differentiation. That the E(2) analogs could lower tumor cell viability and stimulate neuronal differentiation confirmed that gene expression data could accurately distinguish biological activity of the E(2) analogs. The findings reported here confirm that cellular responses can be regulated by making key structural alterations to the core structure of endogenous ER ligands.

  17. Genes involved in the endoplasmic reticulum N-glycosylation pathway of the red microalga Porphyridium sp.: a bioinformatic study.

    PubMed

    Levy-Ontman, Oshrat; Fisher, Merav; Shotland, Yoram; Weinstein, Yacob; Tekoah, Yoram; Arad, Shoshana Malis

    2014-02-07

    N-glycosylation is one of the most important post-translational modifications that influence protein polymorphism, including protein structures and their functions. Although this important biological process has been extensively studied in mammals, only limited knowledge exists regarding glycosylation in algae. The current research is focused on the red microalga Porphyridium sp., which is a potentially valuable source for various applications, such as skin therapy, food, and pharmaceuticals. The enzymes involved in the biosynthesis and processing of N-glycans remain undefined in this species, and the mechanism(s) of their genetic regulation is completely unknown. In this study, we describe our pioneering attempt to understand the endoplasmic reticulum N-Glycosylation pathway in Porphyridium sp., using a bioinformatic approach. Homology searches, based on sequence similarities with genes encoding proteins involved in the ER N-glycosylation pathway (including their conserved parts) were conducted using the TBLASTN function on the algae DNA scaffold contigs database. This approach led to the identification of 24 encoded-genes implicated with the ER N-glycosylation pathway in Porphyridium sp. Homologs were found for almost all known N-glycosylation protein sequences in the ER pathway of Porphyridium sp.; thus, suggesting that the ER-pathway is conserved; as it is in other organisms (animals, plants, yeasts, etc.).

  18. Genes Involved in the Endoplasmic Reticulum N-Glycosylation Pathway of the Red Microalga Porphyridium sp.: A Bioinformatic Study

    PubMed Central

    Levy-Ontman, Oshrat; Fisher, Merav; Shotland, Yoram; Weinstein, Yacob; Tekoah, Yoram; Arad, Shoshana Malis

    2014-01-01

    N-glycosylation is one of the most important post-translational modifications that influence protein polymorphism, including protein structures and their functions. Although this important biological process has been extensively studied in mammals, only limited knowledge exists regarding glycosylation in algae. The current research is focused on the red microalga Porphyridium sp., which is a potentially valuable source for various applications, such as skin therapy, food, and pharmaceuticals. The enzymes involved in the biosynthesis and processing of N-glycans remain undefined in this species, and the mechanism(s) of their genetic regulation is completely unknown. In this study, we describe our pioneering attempt to understand the endoplasmic reticulum N-Glycosylation pathway in Porphyridium sp., using a bioinformatic approach. Homology searches, based on sequence similarities with genes encoding proteins involved in the ER N-glycosylation pathway (including their conserved parts) were conducted using the TBLASTN function on the algae DNA scaffold contigs database. This approach led to the identification of 24 encoded-genes implicated with the ER N-glycosylation pathway in Porphyridium sp. Homologs were found for almost all known N-glycosylation protein sequences in the ER pathway of Porphyridium sp.; thus, suggesting that the ER-pathway is conserved; as it is in other organisms (animals, plants, yeasts, etc.). PMID:24514561

  19. Er1.33Pt3Ga8: A modulated variant of the Er4Pt9Al24-structure type

    NASA Astrophysics Data System (ADS)

    Oswald, Iain W. H.; Gourdon, Olivier; Bekins, Amy; Evans, Jess; Treadwell, LaRico J.; Chan, Julia Y.; Macaluso, Robin T.

    2016-10-01

    Single crystals of Er1.33Pt3Ga8 were synthesized in a molten Ga flux. Er1.33Pt3Ga8 can be considered to be a modulated variant of the Er4Pt9Al24-structure type, where the partial occupancies are ordered. Indeed, the presence of weak satellite reflections indicates a complex organization and distribution of the Er and Ga atoms within the [ErGa] slabs. The structure has been solved based on single crystal X-ray diffraction data in the monoclinic superspace group X2/m(0β0)00 with a commensurate modulated vector q=1/3b*. Precession images also indicate diffusion in the perpendicular direction indicating a partial disorder of this arrangement from layer to layer. In addition, Er1.33Pt3Ga8 shows antiferromagnetic ordering at TN~5 K.

  20. Glucocorticoids alleviate intestinal ER stress by enhancing protein folding and degradation of misfolded proteins.

    PubMed

    Das, Indrajit; Png, Chin Wen; Oancea, Iulia; Hasnain, Sumaira Z; Lourie, Rohan; Proctor, Martina; Eri, Rajaraman D; Sheng, Yong; Crane, Denis I; Florin, Timothy H; McGuckin, Michael A

    2013-06-03

    Endoplasmic reticulum (ER) stress in intestinal secretory cells has been linked with colitis in mice and inflammatory bowel disease (IBD). Endogenous intestinal glucocorticoids are important for homeostasis and glucocorticoid drugs are efficacious in IBD. In Winnie mice with intestinal ER stress caused by misfolding of the Muc2 mucin, the glucocorticoid dexamethasone (DEX) suppressed ER stress and activation of the unfolded protein response (UPR), substantially restoring goblet cell Muc2 production. In mice lacking inflammation, a glucocorticoid receptor antagonist increased ER stress, and DEX suppressed ER stress induced by the N-glycosylation inhibitor, tunicamycin (Tm). In cultured human intestinal secretory cells, in a glucocorticoid receptor-dependent manner, DEX suppressed ER stress and UPR activation induced by blocking N-glycosylation, reducing ER Ca(2+) or depleting glucose. DEX up-regulated genes encoding chaperones and elements of ER-associated degradation (ERAD), including EDEM1. Silencing EDEM1 partially inhibited DEX's suppression of misfolding-induced ER stress, showing that DEX enhances ERAD. DEX inhibited Tm-induced MUC2 precursor accumulation, promoted production of mature mucin, and restored ER exit and secretion of Winnie mutant recombinant Muc2 domains, consistent with enhanced protein folding. In IBD, glucocorticoids are likely to ameliorate ER stress by promoting correct folding of secreted proteins and enhancing removal of misfolded proteins from the ER.

  1. 20 CFR 218.40 - When a widow(er) annuity ends.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) Entitlement based on age. When a widow(er)'s annuity is based on age, the annuity ends with the earliest of... else as the employee's legal widow(er) if entitlement is based on a deemed valid marriage. (b) Disabled... month in which the widow(er) attains age 60 (the disability annuitant then becomes entitled to...

  2. 20 CFR 218.44 - When a remarried widow(er) annuity ends.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) annuity ends. (a) Entitlement based on age. When the remarried widow(er) annuity is based on age, the...(er)— (1) Dies; (2) Becomes entitled to an old age benefit under the Social Security Act that is equal to or larger than the amount of the full remarried widow(er) annuity before reduction for age or...

  3. 20 CFR 218.44 - When a remarried widow(er) annuity ends.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) annuity ends. (a) Entitlement based on age. When the remarried widow(er) annuity is based on age, the...(er)— (1) Dies; (2) Becomes entitled to an old age benefit under the Social Security Act that is equal to or larger than the amount of the full remarried widow(er) annuity before reduction for age or...

  4. 20 CFR 218.44 - When a remarried widow(er) annuity ends.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) annuity ends. (a) Entitlement based on age. When the remarried widow(er) annuity is based on age, the...(er)— (1) Dies; (2) Becomes entitled to an old age benefit under the Social Security Act that is equal to or larger than the amount of the full remarried widow(er) annuity before reduction for age or...

  5. 20 CFR 218.40 - When a widow(er) annuity ends.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) Entitlement based on age. When a widow(er)'s annuity is based on age, the annuity ends with the earliest of... else as the employee's legal widow(er) if entitlement is based on a deemed valid marriage. (b) Disabled... month in which the widow(er) attains age 60 (the disability annuitant then becomes entitled to...

  6. 20 CFR 218.40 - When a widow(er) annuity ends.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) Entitlement based on age. When a widow(er)'s annuity is based on age, the annuity ends with the earliest of... else as the employee's legal widow(er) if entitlement is based on a deemed valid marriage. (b) Disabled... month in which the widow(er) attains age 60 (the disability annuitant then becomes entitled to...

  7. 20 CFR 234.47 - Election of the RLS by a widow(er) or parent.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true Election of the RLS by a widow(er) or parent... parent. (a) An RLS cannot be paid if it appears that there are immediate or future monthly survivor benefits payable to anyone other than a widow(er) or parent. A widow(er) or parent can elect to have...

  8. 20 CFR 228.50 - Tier II annuity component widow(er), child, or parent.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... parent. 228.50 Section 228.50 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE... annuity component widow(er), child, or parent. (a) General. The tier II annuity component is an additional amount payable to a widow(er), disabled widow(er), child, or parent, but not to a surviving...

  9. 20 CFR 234.47 - Election of the RLS by a widow(er) or parent.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Election of the RLS by a widow(er) or parent... parent. (a) An RLS cannot be paid if it appears that there are immediate or future monthly survivor benefits payable to anyone other than a widow(er) or parent. A widow(er) or parent can elect to have...

  10. 20 CFR 228.50 - Tier II annuity component widow(er), child, or parent.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., or parent. 228.50 Section 228.50 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE... annuity component widow(er), child, or parent. (a) General. The tier II annuity component is an additional amount payable to a widow(er), disabled widow(er), child, or parent, but not to a surviving...

  11. 20 CFR 234.47 - Election of the RLS by a widow(er) or parent.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Election of the RLS by a widow(er) or parent... parent. (a) An RLS cannot be paid if it appears that there are immediate or future monthly survivor benefits payable to anyone other than a widow(er) or parent. A widow(er) or parent can elect to have...

  12. 20 CFR 228.50 - Tier II annuity component widow(er), child, or parent.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... parent. 228.50 Section 228.50 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE... annuity component widow(er), child, or parent. (a) General. The tier II annuity component is an additional amount payable to a widow(er), disabled widow(er), child, or parent, but not to a surviving...

  13. 20 CFR 234.47 - Election of the RLS by a widow(er) or parent.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 1 2012-04-01 2012-04-01 false Election of the RLS by a widow(er) or parent... parent. (a) An RLS cannot be paid if it appears that there are immediate or future monthly survivor benefits payable to anyone other than a widow(er) or parent. A widow(er) or parent can elect to have...

  14. 20 CFR 228.50 - Tier II annuity component widow(er), child, or parent.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., or parent. 228.50 Section 228.50 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE... annuity component widow(er), child, or parent. (a) General. The tier II annuity component is an additional amount payable to a widow(er), disabled widow(er), child, or parent, but not to a surviving...

  15. 20 CFR 234.47 - Election of the RLS by a widow(er) or parent.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 1 2014-04-01 2012-04-01 true Election of the RLS by a widow(er) or parent... parent. (a) An RLS cannot be paid if it appears that there are immediate or future monthly survivor benefits payable to anyone other than a widow(er) or parent. A widow(er) or parent can elect to have...

  16. 20 CFR 228.50 - Tier II annuity component widow(er), child, or parent.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., or parent. 228.50 Section 228.50 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE... annuity component widow(er), child, or parent. (a) General. The tier II annuity component is an additional amount payable to a widow(er), disabled widow(er), child, or parent, but not to a surviving...

  17. When to Go to the ER if Your Child Has Asthma

    MedlinePlus

    ... Your 1- to 2-Year-Old When to Go to the ER if Your Child Has Asthma KidsHealth > For Parents > When to Go to the ER if Your Child Has Asthma ... list specific symptoms that are your cue to go to the ER. If old enough, your child ...

  18. PREDICTING ER BINDING AFFINITY FOR EDC RANKING AND PRIORITIZATION: A COMPARISON OF THREE MODELS

    EPA Science Inventory

    A comparative analysis of how three COREPA models for ER binding affinity performed when used to predict potential estrogen receptor (ER) ligands is presented. Models I and II were developed based on training sets of 232 and 279 rat ER binding affinity measurements, respectively....

  19. The endoplasmic reticulum stress/autophagy pathway is involved in cholesterol-induced pancreatic β-cell injury

    PubMed Central

    Kong, Fei-Juan; Wu, Jia-Hua; Sun, Shui-Ya; Zhou, Jia-Qiang

    2017-01-01

    Lipotoxicity has been implicated in pancreatic β-cell dysfunction in type 2 diabetes, but the exact mechanisms remain unknown. The current study explored the role of the endoplasmic reticulum (ER) stress pathway in cholesterol-induced lipotoxicity. Two different insulinoma cell lines were treated with cholesterol with or without inhibitors. ER stress-associated proteins glucose-regulated protein (GRP) 78, activating transcription factor (ATF) 4 and C/EBP homologous protein (CHOP), as was phosphorylation of eukaryotic initiation factor (EIF) 2α, were all up-regulated by cholesterol. Cholesterol also up-regulated microtubule-associated protein 1 light chain 3 (LC3)-II and stimulated the formation of autophagic vacuoles and LC3-II aggregates. Cholesterol-induced autophagy and cell injuries were suppressed by pretreatment with the ER stress inhibitor 4-phenylbutyrate (4-PBA). Pretreatment with autophagy inhibitors E-64d/pepstatin A increased ER stress-induced cell injuries as indicated by increased cell apoptosis and decreased insulin secretion. These results suggest that cholesterol treatment induces apoptosis and dysfunction of β-cells, and enhances autophagy through activation of the ER stress pathway. More importantly, autophagy induced by cholesterol may protect β-cells against ER stress-associated cell damages. PMID:28294183

  20. The Unfolded Protein Response Element IRE1α Senses Bacterial Proteins Invading the ER to Activate RIG-I and Innate Immune Signaling

    PubMed Central

    Cho, Jin A.; Lee, Ann-Hwee; Platzer, Barbara; Cross, Benedict C.S.; Gardner, Brooke M.; De Luca, Heidi; Luong, Phi; Harding, Heather P.; Glimcher, Laurie H.; Walter, Peter; Fiebiger, Edda; Ron, David; Kagan, Jonathan C.; Lencer, Wayne I.

    2013-01-01

    SUMMARY The plasma membrane and all membrane-bound organelles except for the Golgi and endoplasmic reticulum (ER) are equipped with pattern-recognition molecules to sense microbes or their products and induce innate immunity for host defense. Here, we report that inositol-requiring-1α (IRE1α), an ER protein that signals in the unfolded protein response (UPR), is activated to induce inflammation by binding a portion of cholera toxin as it co-opts the ER to cause disease. Other known UPR transducers, including the IRE1α-dependent transcription factor XBP1, are dispensable for this signaling. The inflammatory response depends instead on the RNase activity of IRE1α to degrade endogenous mRNA, a process termed regulated IRE1α-dependent decay (RIDD) of mRNA. The mRNA fragments produced engage retinoic-acid inducible gene 1 (RIG-I), a cyto-solic sensor of RNA viruses, to activate NF-κB and interferon pathways. We propose IRE1α provides for a generalized mechanism of innate immune surveillance originating within the ER lumen. PMID:23684307

  1. Cocaine-mediated microglial activation involves the ER stress-autophagy axis

    PubMed Central

    Guo, Ming-Lei; Liao, Ke; Periyasamy, Palsamy; Yang, Lu; Cai, Yu; Callen, Shannon E; Buch, Shilpa

    2015-01-01

    Cocaine abuse leads to neuroinflammation, which, in turn, contributes to the pathogenesis of neurodegeneration associated with advanced HIV-1 infection. Autophagy plays important roles in both innate and adaptive immune responses. However, the possible functional link between cocaine and autophagy has not been explored before. Herein, we demonstrate that cocaine exposure induced autophagy in both BV-2 and primary rat microglial cells as demonstrated by a dose- and time-dependent induction of autophagy-signature proteins such as BECN1/Beclin 1, ATG5, and MAP1LC3B. These findings were validated wherein cocaine treatment of BV-2 cells resulted in increased formation of puncta in cells expressing either endogenous MAP1LC3B or overexpressing GFP-MAP1LC3B. Specificity of cocaine-induced autophagy was confirmed by treating cells with inhibitors of autophagy (3-MA and wortmannin). Intriguingly, cocaine-mediated induction of autophagy involved upstream activation of 2 ER stress pathways (EIF2AK3- and ERN1-dependent), as evidenced by the ability of the ER stress inhibitor salubrinal to ameliorate cocaine-induced autophagy. In vivo validation of these findings demonstrated increased expression of BECN1, ATG5, and MAP1LC3B-II proteins in cocaine-treated mouse brains compared to untreated animals. Increased autophagy contributes to cocaine-mediated activation of microglia since pretreatment of cells with wortmannin resulted in decreased expression and release of inflammatory factors (TNF, IL1B, IL6, and CCL2) in microglial cells. Taken together, our findings suggest that cocaine exposure results in induction of autophagy that is closely linked with neuroinflammation. Targeting autophagic proteins could thus be considered as a therapeutic strategy for the treatment of cocaine-related neuroinflammation diseases. PMID:26043790

  2. Cocaine-mediated microglial activation involves the ER stress-autophagy axis.

    PubMed

    Guo, Ming-Lei; Liao, Ke; Periyasamy, Palsamy; Yang, Lu; Cai, Yu; Callen, Shannon E; Buch, Shilpa

    2015-01-01

    Cocaine abuse leads to neuroinflammation, which, in turn, contributes to the pathogenesis of neurodegeneration associated with advanced HIV-1 infection. Autophagy plays important roles in both innate and adaptive immune responses. However, the possible functional link between cocaine and autophagy has not been explored before. Herein, we demonstrate that cocaine exposure induced autophagy in both BV-2 and primary rat microglial cells as demonstrated by a dose- and time-dependent induction of autophagy-signature proteins such as BECN1/Beclin 1, ATG5, and MAP1LC3B. These findings were validated wherein cocaine treatment of BV-2 cells resulted in increased formation of puncta in cells expressing either endogenous MAP1LC3B or overexpressing GFP-MAP1LC3B. Specificity of cocaine-induced autophagy was confirmed by treating cells with inhibitors of autophagy (3-MA and wortmannin). Intriguingly, cocaine-mediated induction of autophagy involved upstream activation of 2 ER stress pathways (EIF2AK3- and ERN1-dependent), as evidenced by the ability of the ER stress inhibitor salubrinal to ameliorate cocaine-induced autophagy. In vivo validation of these findings demonstrated increased expression of BECN1, ATG5, and MAP1LC3B-II proteins in cocaine-treated mouse brains compared to untreated animals. Increased autophagy contributes to cocaine-mediated activation of microglia since pretreatment of cells with wortmannin resulted in decreased expression and release of inflammatory factors (TNF, IL1B, IL6, and CCL2) in microglial cells. Taken together, our findings suggest that cocaine exposure results in induction of autophagy that is closely linked with neuroinflammation. Targeting autophagic proteins could thus be considered as a therapeutic strategy for the treatment of cocaine-related neuroinflammation diseases.

  3. Electro-optic coefficients r13 and r33 of singly Er3+-doped and In3+/Er3+-codoped LiNbO3 crystals

    NASA Astrophysics Data System (ADS)

    Du, Wan-Ying; Zhang, Pei; Zhang, Zi-Bo; Ren, Shuai; Wong, Wing-Han; Yu, Dao-Yin; Pun, Edwin Yue-Bun; Zhang, De-Long

    2017-01-01

    A series of singly Er3+-doped and doubly In3+/Er3+-doped congruent LiNbO3 crystals were grown by Czochralski method. The Er3+-only doped crystals were grown from the growth melts doped with different concentrations of Er2O3 up to 1 mol%, and the In3+/Er3+-codoped crystals from the melts doped with fixed 0.5 mol% Er2O3 while varied In2O3 contents of 0.0, 0.5, 1.0 and 1.5 mol%. The electro-optic coefficients γ13 and γ33 of these doped crystals were measured by Mach-Zehnder interferometry. Both clamped and unclamped coefficients were measured. The results show that both γ13 and γ33 reveal small Er3+ and In3+ doping effects. In the Er3+-only doping case, γ13 almost does not change within the experimental error of 3%, γ33 reveals a degradation tendency with a rise in Er3+ doping level, but the degradation is no more than 5% in the considered Er3+ concentration range 0-3.0 mol% (in crystal). In the In3+/Er3+-codoping case, both γ13 and γ33 can be regarded as unchanged in the studied In3+ concentration range of 0-2.6 mol% (in crystal) within the error. The small Er3+ or In3+ doping effect is desired in light of electro-optic application of these crystals. It is qualitatively explained on the basis of EO coefficient model and doping effect on defect structure of LiNbO3.

  4. Differences between the TERF and the ERS tritium capture systems

    SciTech Connect

    Hedley, W.H.; Lamberger, P.H.; Colvin, C.M.; Gibbs, G.E.; Adams, F.S.; Bowser, R.P.; Kissner, T.J.; Morgan, F.E.; Schmidt, M.J.; Van Patten, J.F.; Wieneke, R.E.

    1991-12-31

    The TERF and the ERS tritium capture systems are alike in that they both use the ``oxidize and dry`` principle to remove tritium from gases, but they differ significantly in engineering details. The newer TERF system benefited in many ways from experience with the ERS. The TERF is expected to: (1) operate at a higher pressure, leading to greater throughput, (2) have redesigned reactors with better efficiency to process tritiated organic compounds, (3) have better energy conservation, (4) use an advanced process control system to provide more versatility in operation of the system, to account for the amount of tritium in the system at all times, and to more completely log operating results, (5) utilize more corrosion resistant materials to minimize maintenance, and (6) provide double containment of all pressurized tritium containing equipment to reduce tritium losses and increase operating safety. 6 refs.

  5. Differences between the TERF and the ERS tritium capture systems

    SciTech Connect

    Hedley, W.H.; Lamberger, P.H.; Colvin, C.M.; Gibbs, G.E.; Adams, F.S.; Bowser, R.P.; Kissner, T.J.; Morgan, F.E.; Schmidt, M.J.; Van Patten, J.F.; Wieneke, R.E.

    1991-01-01

    The TERF and the ERS tritium capture systems are alike in that they both use the oxidize and dry'' principle to remove tritium from gases, but they differ significantly in engineering details. The newer TERF system benefited in many ways from experience with the ERS. The TERF is expected to: (1) operate at a higher pressure, leading to greater throughput, (2) have redesigned reactors with better efficiency to process tritiated organic compounds, (3) have better energy conservation, (4) use an advanced process control system to provide more versatility in operation of the system, to account for the amount of tritium in the system at all times, and to more completely log operating results, (5) utilize more corrosion resistant materials to minimize maintenance, and (6) provide double containment of all pressurized tritium containing equipment to reduce tritium losses and increase operating safety. 6 refs.

  6. Polarization maintaining linear cavity Er-doped fiber femtosecond laser

    NASA Astrophysics Data System (ADS)

    Jang, Heesuk; Jang, Yoon-Soo; Kim, Seungman; Lee, Keunwoo; Han, Seongheum; Kim, Young-Jin; Kim, Seung-Woo

    2015-10-01

    We present a polarization-maintaining (PM) type of Er-doped fiber linear oscillator designed to produce femtosecond laser pulses with high operational stability. Mode locking is activated using a semiconductor saturable absorber mirror (SESAM) attached to one end of the linear PM oscillator. To avoid heat damage, the SESAM is mounted on a copper-silicon-layered heat sink and connected to the linear oscillator through a fiber buffer dissipating the residual pump power. A long-term stability test is performed to prove that the proposed oscillator design maintains a soliton-mode single-pulse operation without breakdown of mode locking over a week period. With addition of an Er-doped fiber amplifier, the output power is raised to 180 mW with 60 fs pulse duration, from which an octave-spanning supercontinuum is produced.

  7. Ice sheet topography from retracked ERS-1 altimetry

    NASA Technical Reports Server (NTRS)

    Zwally, H. Jay; Brenner, Anita C.; Dimarzio, John; Seiss, Timothy

    1994-01-01

    An objective of the ERS-1 radar altimeter is to measure the surface topography of the polar ice sheets to a precision on the order of a meter. ERS-1 Waveform Altimeter Product (WAP) data was corrected for several processing errors. A range correction from the WAP waveforms, using the multiparameter retracking algorithm to account for range tracking limitations inherent to radar altimetry, was derived. From crossover analysis, the resulting precision is shown to be about 2.1 m in ocean mode and 2.2 m in ice mode. A topography map, produced with 23 days of corrected data, shows details of the western part of west Antarctic ice sheet and part of the Ross ice shelf including ice divides, ice stream boundaries, and ice shelf grounding lines.

  8. Atmospheric Ionizing Radiation (AIR) ER-2 Preflight Analysis

    NASA Technical Reports Server (NTRS)

    Tai, Hsiang; Wilson, John W.; Maiden, D. L.

    1998-01-01

    Atmospheric ionizing radiation (AIR) produces chemically active radicals in biological tissues that alter the cell function or result in cell death. The AIR ER-2 flight measurements will enable scientists to study the radiation risk associated with the high-altitude operation of a commercial supersonic transport. The ER-2 radiation measurement flights will follow predetermined, carefully chosen courses to provide an appropriate database matrix which will enable the evaluation of predictive modeling techniques. Explicit scientific results such as dose rate, dose equivalent rate, magnetic cutoff, neutron flux, and air ionization rate associated with those flights are predicted by using the AIR model. Through these flight experiments, we will further increase our knowledge and understanding of the AIR environment and our ability to assess the risk from the associated hazard.

  9. Tunable eye-safe Er:YAG laser

    NASA Astrophysics Data System (ADS)

    Němec, M.; Šulc, J.; Indra, L.; Fibrich, M.; Jelínková, H.

    2015-01-01

    Er:YAG crystal was investigated as the gain medium in a diode (1452 nm) pumped tunable laser. The tunability was reached in an eye-safe region by an intracavity birefringent filter. The four tuning bands were obtained peaking at wavelengths 1616, 1632, 1645, and 1656 nm. The broadest continuous tunability was 6 nm wide peaking at 1616 nm. The laser was operating in a pulsed regime (10 ms pulse length, 10 Hz repetition rate). The maximum mean output power was 26.5 mW at 1645 nm. The constructed system demonstrated the tunability of a resonantly diode-pumped Er:YAG laser which could be useful in the development of compact diode-pumped lasers for spectroscopic applications.

  10. Hypothalamic ER stress: A bridge between leptin resistance and obesity.

    PubMed

    Ramírez, Sara; Claret, Marc

    2015-06-22

    The prevalence of obesity has increased worldwide at an alarming rate. However, non-invasive pharmacological treatments remain elusive. Leptin resistance is a general feature of obesity, thus strategies aimed at enhancing the sensitivity to this hormone may constitute an excellent therapeutical approach to counteract current obesity epidemics. Nevertheless, the etiology and neuronal basis of leptin resistance remains an enigma. A recent hypothesis gaining substantial experimental support is that hypothalamic endoplasmic reticulum (ER) stress plays a causal role in the development of leptin resistance and obesity. The objective of this review article is to provide an updated view on current evidence connecting hypothalamic ER stress with leptin resistance. We discuss the experimental findings supporting this hypothesis, as well as the potential causes and underlying mechanisms leading to this metabolic disorder. Understanding these mechanisms may provide key insights into the development of novel intervention approaches.

  11. Multiple magnetic transitions in Er2Ni2Pb

    NASA Astrophysics Data System (ADS)

    Chinchure, Aravind D.; Muñoz-Sandoval, E.; Mydosh, J. A.

    2001-07-01

    We have fabricated single-phase samples and measured the bulk properties for one (Er) of a series of ternary, heavy rare-earth, 221 ``plumbide'' intermetallic compounds R2Ni2Pb (R=rare earths). These materials form in the orthorhombic (space group Cmmm) structure which is isostructural to Mn2AlB2 compounds. Our results of susceptibility, magnetization, heat capacity, and (magneto) resistivity on Er2Ni2Pb show (sharp) multiple antiferromagnetic transitions and strong field dependences in all bulk properties for the temperature range 2-10 K. We relate this magnetic behavior to the unusual R symmetry (partially frustrated) of the highly anisotropic plumbide crystal structure.

  12. Er:YAG and adhesion in conservative dentistry : clinical overview

    PubMed Central

    Fornaini, Carlo

    2013-01-01

    The notion of utilizing laser technology in conservative dentistry was proposed in 1990 by Hibst and Keller, who introduced the possibility of using an Er:YAG laser as alternative to conventional instruments such as the turbine and micro-motor. In subsequent years a continuing effort has been made by clinicians, researchers and commercial companies to improve the technology. The aim of this clinical study is to demonstrate, by the description of different clinical cases, the possibilities and the advantages of using Er:YAG lasers in conservative dentistry and to show that better results may be achieved in terms of stronger adhesion, less invasiveness, reduced pain as well as greater comfort and satisfaction of patients. PMID:24155547

  13. Immunogenic tumor cell death for optimal anticancer therapy: the calreticulin exposure pathway.

    PubMed

    Zitvogel, Laurence; Kepp, Oliver; Senovilla, Laura; Menger, Laurie; Chaput, Nathalie; Kroemer, Guido

    2010-06-15

    In response to some chemotherapeutic agents such as anthracyclines and oxaliplatin, cancer cells undergo immunogenic apoptosis, meaning that their corpses are engulfed by dendritic cells and that tumor cell antigens are presented to tumor-specific CD8(+) T cells, which then control residual tumor cells. One of the peculiarities of immunogenic apoptosis is the early cell surface exposure of calreticulin (CRT), a protein that usually resides in the lumen of the endoplasmic reticulum (ER). When elicited by anthracyclines or oxaliplatin, the CRT exposure pathway is activated by pre-apoptotic ER stress and the phosphorylation of the eukaryotic translation initiation factor eIF2alpha by the kinase PERK, followed by caspase-8-mediated proteolysis of the ER-sessile protein BAP31, activation of the pro-apoptotic proteins Bax and Bak, anterograde transport of CRT from the ER to the Golgi apparatus and exocytosis of CRT-containing vesicles, finally resulting in CRT translocation onto the plasma membrane surface. Interruption of this complex pathway abolishes CRT exposure, annihilates the immunogenicity of apoptosis, and reduces the immune response elicited by anticancer chemotherapies. We speculate that human cancers that are incapable of activating the CRT exposure pathway are refractory to the immune-mediated component of anticancer therapies.

  14. Final Report DE-FG02-07ER64416

    SciTech Connect

    Seymour, Joseph D.

    2014-02-01

    The document provides the Final Report for DE-FG02-07ER64416 on the use of magnetic resonance (MR) methods to quantify transport in porous media impacted by biological and chemical processes. Products resulting from the research in the form of peer reviewed publications and conference presentations are presented. The research correlated numerical simulations and MR measurements to test simulation methodology. Biofilm and uranium detection by MR was demonstrated.

  15. Impact of COX2 genotype, ER status and body constitution on risk of early events in different treatment groups of breast cancer patients.

    PubMed

    Markkula, Andrea; Simonsson, Maria; Rosendahl, Ann H; Gaber, Alexander; Ingvar, Christian; Rose, Carsten; Jernström, Helena

    2014-10-15

    The COX2 rs5277 (306G>C) polymorphism has been associated with inflammation-associated cancers. In breast cancer, tumor COX-2 expression has been associated with increased estrogen levels in estrogen receptor (ER)-positive and activated Akt-pathway in ER-negative tumors. Our study investigated the impact of COX2 genotypes on early breast cancer events and treatment response in relation to tumor ER status and body constitution. In Sweden, between 2002 and 2008, 634 primary breast cancer patients, aged 25-99 years, were included. Disease-free survival was assessed for 570 rs5277-genotyped patients. Body measurements and questionnaires were obtained preoperatively. Clinical data, patient- and tumor-characteristics were obtained from questionnaires, patients' charts, population registries and pathology reports. Minor allele(C) frequency was 16.1%. Genotype was not linked to COX-2 tumor expression. Median follow-up was 5.1 years. G/G genotype was not associated with early events in patients with ER-positive tumors, adjusted HR 0.77 (0.46-1.29), but conferred an over 4-fold increased risk in patients with ER-negative tumors, adjusted HR 4.41 (1.21-16.02)(p(interaction) = 0.015). Chemotherapy-treated G/G-carriers with a breast volume ≥ 850 ml had an increased risk of early events irrespective of ER status, adjusted HR 8.99 (1.14-70.89). Endocrine-treated C-allele carriers with ER-positive tumors and a breast volume ≥ 850 ml had increased risk of early events, adjusted HR 2.30 (1.12-4.75). COX2 genotype, body constitution and ER status had a combined effect on the risk of early events and treatment response. The high risk for early events in certain subgroups of patients suggests that COX2 genotype in combination with body measurements may identify patients in need of more personalized treatment.

  16. PATHWAYS - ELECTRON TUNNELING PATHWAYS IN PROTEINS

    NASA Technical Reports Server (NTRS)

    Beratan, D. N.

    1994-01-01

    The key to understanding the mechanisms of many important biological processes such as photosynthesis and respiration is a better understanding of the electron transfer processes which take place between metal atoms (and other groups) fixed within large protein molecules. Research is currently focused on the rate of electron transfer and the factors that influence it, such as protein composition and the distance between metal atoms. Current models explain the swift transfer of electrons over considerable distances by postulating bridge-mediated tunneling, or physical tunneling pathways, made up of interacting bonds in the medium around and between donor and acceptor sites. The program PATHWAYS is designed to predict the route along which electrons travel in the transfer processes. The basic strategy of PATHWAYS is to begin by recording each possible path element on a connectivity list, including in each entry which two atoms are connected and what contribution the connection would make to the overall rate if it were included in a pathway. The list begins with the bonded molecular structure (including the backbone sequence and side chain connectivity), and then adds probable hydrogen bond links and through-space contacts. Once this list is completed, the program runs a tree search from the donor to the acceptor site to find the dominant pathways. The speed and efficiency of the computer search offers an improvement over manual techniques. PATHWAYS is written in FORTRAN 77 for execution on DEC VAX series computers running VMS. The program inputs data from four data sets and one structure file. The software was written to input BIOGRAF (old format) structure files based on x-ray crystal structures and outputs ASCII files listing the best pathways and BIOGRAF vector files containing the paths. Relatively minor changes could be made in the input format statements for compatibility with other graphics software. The executable and source code are included with the

  17. Efficient visible upconversion luminescence in Er3+ and Er3+/Yb3+ co-doped Y2O3 phosphors obtained by solution combustion reaction.

    PubMed

    Singh, Vijay; Haritha, P; Venkatramu, V; Kim, S H

    2014-05-21

    Combustion derived Er(3+) -doped Y2O3 and Er(3+)/Yb(3+)co-doped Y2O3 powders have been characterized by X-ray diffraction, energy dispersive X-ray analysis, Fourier transform infrared spectroscopy and laser excited spectroscopy. Formation of Y2O3 phosphor was confirmed by X-ray diffraction and energy dispersive X-ray analysis. The vibrational properties of Y2O3 powder was studied by Fourier transform infrared spectroscopy. The luminescence spectra of Er(3+) -doped and Er(3+)/Yb(3+) co-doped Y2O3 powders were studied under 379nm excitation. The strong up-conversion luminescence for Er(3+) -doped and Er(3+)/Yb(3+) co-doped Y2O3 powders have been observed under 978nm laser excitation. The effect of Yb(3+) addition on optical and luminescence properties of Er(3+):Y2O3 powders were studied. The ratio of red to green intensity has been enhanced when Er(3+) -doped Y2O3 is co-doped with Yb(3+) ions. The effect of co-doping of Yb(3+) ions on the visible luminescence intensity of Er(3+) has been studied and the mechanism responsible for the variation in the green and red intensity is discussed.

  18. Completion Report for Well Cluster ER-5-4

    SciTech Connect

    U.S. Department of Energy, National Nuclear Security Administration, Nevada Site Office; Bechtel Nevada

    2005-02-01

    Well Cluster ER-5-4 was drilled for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, in support of the Nevada Environmental Restoration Project at the Nevada Test Site, Nye County, Nevada. The cluster consists of two wells, positioned about 30 meters apart on the same drill pad, constructed as part of a hydrogeologic investigation program for Frenchman Flat at the Nevada Test Site. Detailed lithologic descriptions with preliminary stratigraphic assignments for the well cluster are included in this report. These are based on composite drill cuttings collected every 3 meters, and 156 sidewall samples taken at various depths below 192 meters in both boreholes, supplemented by geophysical log data. Detailed petrographic, chemical, and mineralogical studies of rock samples were conducted on 122 samples. Well ER-5-4 penetrated approximately 1,120 meters of Quaternary and Tertiary alluvium before reaching total depth in Tertiary volcanic rocks at 1,137.5 meters. The deeper Well ER-5-4 No.2 penetrated 1,120.4 meters of alluvial sediments, and was terminated within Tertiary volcanic rocks at a depth of 2,133.6 meters, indicating that Paleozoic rocks are deeper than expected at this site.

  19. Completion Report for Well Cluster ER-6-1

    SciTech Connect

    Bechtel Nevada

    2004-10-01

    Well Cluster ER-6-1 was constructed for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office in support of the Nevada Environmental Restoration Division at the Nevada Test Site, Nye County, Nevada. This work was initiated as part of the Groundwater Characterization Project, now known as the Underground Test Area Project. The well cluster is located in southeastern Yucca Flat. Detailed lithologic descriptions with stratigraphic assignments for Well Cluster ER-6-1 are included in this report. These are based on composite drill cuttings collected every 3 meters and conventional core samples taken below 639 meters, supplemented by geophysical log data. Detailed petrographic, chemical, and mineralogical studies of rock samples were conducted on 11 samples to resolve complex interrelationships between several of the Tertiary tuff units. Additionally, paleontological analyses by the U.S. Geological Survey confirmed the stratigraphic assignments below 539 meters within the Paleozoic sedimentary section. All three wells in the Well ER-6-1 cluster were drilled within the Quaternary and Tertiary alluvium section, the Tertiary volcanic section, and into the Paleozoic sedimentary section.

  20. An Overview of ER-2 Platform Science during TC4

    NASA Astrophysics Data System (ADS)

    Platnick, S.; Newman, P. A.

    2007-12-01

    The NASA high-altitude ER-2 aircraft flew 11 science flight out of San Jose, Costa Rica during July and August 2007 as part of the NASA-sponsored Tropical Composition, Clouds and Climate Coupling Experiment (TC4). The ER-2 flew a remote sensing payload consisting of passive optical and microwave imagers (MAS/MASTER, CoSSIR, AMPR), a high spectral resolution IR imager (S-HIS), active sensors (CPL lidar, CRS and EDOP radars), spectral solar (SSFR) and IR flux radiometers, a microwave temperature profiler (MTP), and a visible video camera (MVIS). This suite of sensors provided a high spatial resolution simulator for cloud, aerosol, sounding, and trace gas retrieval capabilities from the "A-Train" constellation, in particular, the Aqua, CloudSat, and CALIPSO satellites. In this talk we present an overview of the ER-2 TC4 science and validation objectives, and a summary of the campaign accomplishments. Science goals included observations of convective system development, anvil cirrus property evolution (i.e., microphysics, optical properties, narrow and broadband radiative fluxes), tropical Tropopause Transition Layer (TTL) and subvisual cirrus detection and characterization, marine boundary layer cloud properties, aerosol transport and optical properties, and trace gas and atmospheric state characteristics. Coordination with the DC-8 and/or WB-57 aircrafts allowed for validation of various retrievals from these observations. Morning flights (due to adverse local afternoon weather conditions) included coordination with the Terra spacecraft when feasible.

  1. Tunable, diode side-pumped Er: YAG laser

    DOEpatents

    Hamilton, Charles E.; Furu, Laurence H.

    1997-01-01

    A discrete-element Er:YAG laser, side pumped by a 220 Watt peak-power InGaAs diode array, generates >500 mWatts at 2.94 .mu.m, and is tunable over a 6 nm range near about 2.936 .mu.m. The oscillator is a plano-concave resonator consisting of a concave high reflector, a flat output coupler, a Er:YAG crystal and a YAG intracavity etalon, which serves as the tuning element. The cavity length is variable from 3 cm to 4 cm. The oscillator uses total internal reflection in the Er:YAG crystal to allow efficient coupling of the diode emission into the resonating modes of the oscillator. With the tuning element removed, the oscillator produces up to 1.3 Watts of average power at 2.94 .mu.m. The duty factor of the laser is 6.5% and the repetition rate is variable up to 1 kHz. This laser is useful for tuning to an atmospheric transmission window at 2.935 .mu.m (air wavelength). The laser is also useful as a spectroscopic tool because it can access several infrared water vapor transitions, as well as transitions in organic compounds. Other uses include medical applications (e.g., for tissue ablation and uses with fiber optic laser scalpels) and as part of industrial effluent monitoring systems.

  2. Tunable, diode side-pumped Er:YAG laser

    DOEpatents

    Hamilton, C.E.; Furu, L.H.

    1997-04-22

    A discrete-element Er:YAG laser, side pumped by a 220 Watt peak-power InGaAs diode array, generates >500 mWatts at 2.94 {micro}m, and is tunable over a 6 nm range near about 2.936 {micro}m. The oscillator is a plano-concave resonator consisting of a concave high reflector, a flat output coupler, a Er:YAG crystal and a YAG intracavity etalon, which serves as the tuning element. The cavity length is variable from 3 cm to 4 cm. The oscillator uses total internal reflection in the Er:YAG crystal to allow efficient coupling of the diode emission into the resonating modes of the oscillator. With the tuning element removed, the oscillator produces up to 1.3 Watts of average power at 2.94 {micro}m. The duty factor of the laser is 6.5% and the repetition rate is variable up to 1 kHz. This laser is useful for tuning to an atmospheric transmission window at 2.935 {micro}m (air wavelength). The laser is also useful as a spectroscopic tool because it can access several infrared water vapor transitions, as well as transitions in organic compounds. Other uses include medical applications (e.g., for tissue ablation and uses with fiber optic laser scalpels) and as part of industrial effluent monitoring systems. 4 figs.

  3. Er:YAG clinical results on hard tissue: phase I

    NASA Astrophysics Data System (ADS)

    Cozean, Colette D.; Powell, G. L.

    1998-04-01

    Objective: This study was performed in order to establish that the pulpal and dentinal tissue are safe when exposed to the 2.94 micron pulsed Er:YAG laser radiation for the procedures of caries removal, cavity preparation, and etching prior to acid etching. This presentation discusses the histological results of a double-blind study comparing a pulsed Er:YAG with a standard dental drill. Methods: A double-blind histological evaluation of the pulpal and dentinal tissue changes induced by the Erbium laser and the dental drill was conducted on teeth extracted immediately following the dental procedure and at various intervals up to 1 year post-treatment. A statistical analysis was used to determine if any statistically significant clinical differences in dental tissue response could be observed between the Er:YAG laser and the standard dental drill. Conclusions: Analysis of the results indicated there were no significant differences observed between the laser and control groups in this study.

  4. Spectroscopic properties of Er3+-doped fluorotellurite glasses

    NASA Astrophysics Data System (ADS)

    Miguel, A.; Al-Saleh, M.; Azkargorta, J.; Morea, R.; Gonzalo, J.; Arriandiaga, M. A.; Fernandez, J.; Balda, R.

    2013-09-01

    In this work we report the spectroscopic properties of Er3+-doped fluorotellurite glasses in the 46.6TeO2-18.2ZnO-35.2ZnF2 system for different ErF3 concentrations between 0.5 and 3 wt%. Absorption and emission spectra and lifetimes have been measured in the visible and near infrared regions. Judd-Ofelt analysis has been performed to estimate the radiative transition probabilities. The high content of ZnF2 in this glass decreases the covalency degree in rare-earth site and results in a lower value of Ω2 if compared with zinc tellurite glasses. The infrared emissions at 1532 nm are broader by nearly 30 nm in these glasses if compared to silica glass. This broad emission together with the high values of the stimulated emission cross-section and lifetime of level 4I13/2 make these glasses attractive for broadband amplifiers. The decays from level 4I13/2 are single exponentials for all concentrations which indicates a fast energy diffusion between Er3+ ions. Similar values for the critical radius and energy transfer microparameter are obtained for the different concentrations, which supports the dipole-dipole transfer hypothesis.

  5. Er + medium energy ion implantation into lithium niobate

    NASA Astrophysics Data System (ADS)

    Svecova, B.; Nekvindova, P.; Mackova, A.; Oswald, J.; Vacik, J.; Grötzschel, R.; Spirkova, J.

    2009-05-01

    Erbium-doped lithium niobate (Er:LiNbO3) is a prospective photonics component, operating at 1.5 μm, which could find its use chiefly as an optical amplifier or waveguide laser. In this study, we have focused on the properties of the optically active Er:LiNbO3 layers, which are fabricated by medium energy ion implantation under various experimental conditions. Erbium ions were implanted at energies of 330 and 500 keV with fluences of 1.0 × 1015, 2.5 × 1015 and 1.0 × 1016 cm-2 into LiNbO3 single-crystalline cuts of various orientations. The as-implanted samples were annealed in air at 350 °C for 5 h. The depth distribution and diffusion profiles of the implanted Er were measured by Rutherford Backscattering Spectroscopy (RBS) using 2 MeV He+ ions. The projected range RP and projected range straggling ΔRP were calculated employing the SRIM code. The damage distribution and structural changes were described using the RBS/channelling method. Changes of the lithium concentration depth distribution were studied by Neutron Depth Profiling (NDP). The photoluminescence spectra of the samples were measured to determine whether the emission was in the desired region of 1.5 μm. The obtained data made it possible to reveal the relations between the structural changes of erbium-implanted lithium niobate and its luminescence properties important for photonics applications.

  6. Balanced Ero1 activation and inactivation establishes ER redox homeostasis

    PubMed Central

    Kim, Sunghwan; Sideris, Dionisia P.; Sevier, Carolyn S.

    2012-01-01

    The endoplasmic reticulum (ER) provides an environment optimized for oxidative protein folding through the action of Ero1p, which generates disulfide bonds, and Pdi1p, which receives disulfide bonds from Ero1p and transfers them to substrate proteins. Feedback regulation of Ero1p through reduction and oxidation of regulatory bonds within Ero1p is essential for maintaining the proper redox balance in the ER. In this paper, we show that Pdi1p is the key regulator of Ero1p activity. Reduced Pdi1p resulted in the activation of Ero1p by direct reduction of Ero1p regulatory bonds. Conversely, upon depletion of thiol substrates and accumulation of oxidized Pdi1p, Ero1p was inactivated by both autonomous oxidation and Pdi1p-mediated oxidation of Ero1p regulatory bonds. Pdi1p responded to the availability of free thiols and the relative levels of reduced and oxidized glutathione in the ER to control Ero1p activity and ensure that cells generate the minimum number of disulfide bonds needed for efficient oxidative protein folding. PMID:22412017

  7. Development of a stable ERroGFP variant suitable for monitoring redox dynamics in the ER

    PubMed Central

    Hoseki, Jun; Oishi, Asami; Fujimura, Takaaki; Sakai, Yasuyoshi

    2016-01-01

    The endoplasmic reticulum (ER) is an essential organelle for cellular metabolic homeostasis including folding and maturation of secretory and membrane proteins. Disruption of ER proteostasis has been implicated in the pathogenesis of various diseases such as diabetes and neurodegenerative diseases. The ER redox state, which is an oxidative environment suitable for disulfide-bond formation, is essential for ER protein quality control. Hence, detection of the ER redox state, especially in living cells, is essential to understand the mechanism by which the redox state of the ER is maintained. However, methods to detect the redox state of the ER have not been well-established because of inefficient folding and stability of roGFP variants with oxidative redox potential like roGFP-iL. Here we have improved the folding efficiency of ER-targeted roGFP-iL (ERroGFP-iL) in cells by introducing superfolder GFP (sfGFP) mutations. Four specific amino acid substitutions (S30R, Y39N, T105N and I171V) greatly improved folding efficiency in Escherichia coli and in the ER of HeLa cells, as well as the thermostability of the purified proteins. Introduction of these mutations also enhanced the dynamic range for redox change both in vitro and in the ER of living cells. ER-targeted roGFP-S4 (ERroGFP-S4) possessing these four mutations could detect physiological redox changes within the ER. ERroGFP-S4 is therefore a novel probe suitable for monitoring redox change in the ER. ERroGFP-S4 can be applied to detect aberrant ER redox states associated with various pathological conditions and to identify the mechanisms used to maintain the redox state of the ER. PMID:26934978

  8. Albumin overload down-regulates integrin-β1 through reactive oxygen species-endoplasmic reticulum stress pathway in podocytes.

    PubMed

    Cheng, Yu-Chi; Chen, Chien-An; Chang, Jer-Ming; Chen, Hung-Chun

    2015-08-01

    Proteinuria is a major hallmark of glomerular nephropathy and endoplasmic reticulum (ER) stress plays an important role in glomerular nephropathy. The protein levels of integrin-β1 in podocytes are found to be negative correlation with amount of proteinuria. This study investigated whether urinary protein, particularly albumin, induced ER stress that consequently reduced integrin-β1 expression. All experiments were performed using primary cultured rat podocyte. Protein and mRNA expression were measured by western blotting and semiquantified reverse transcriptase polymerase chain reaction. Albumin uptake was found at 1 h after albumin addition. Albumin reduced precursor and mature forms of integrin-β1, but did not change mRNA levels of integrin-β1. Albumin induced reactive oxygen species (ROS) generation and ER stress. Antioxidant (N-acetylcysteine) suppressed albumin-induced ER stress and decrements in precursor and mature forms of integrin-β1. Then, ER stress inhibitors (4-phenylbutyrate and salubrinal) also inhibited albumin-induced decrements in precursor and mature forms of integrin-β1. The potent ER stress inducers (thapsigargin and tunicamycin) directly decreased precursor and mature forms of integrin-β1 and led appearance of unglycosylated core protein of integrin-β1. Our results show that in proteinuric disease, albumin decreases precursor and mature forms of integrin-β1 through ROS-ER stress pathway in podocytes.

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

    USGS Publications Warehouse

    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.

  10. Profiling of the Tox21 10K compound library for agonists and antagonists of the estrogen receptor alpha signaling pathway

    PubMed Central

    Huang, Ruili; Sakamuru, Srilatha; Martin, Matt T.; Reif, David M.; Judson, Richard S.; Houck, Keith A.; Casey, Warren; Hsieh, Jui-Hua; Shockley, Keith R.; Ceger, Patricia; Fostel, Jennifer; Witt, Kristine L.; Tong, Weida; Rotroff, Daniel M.; Zhao, Tongan; Shinn, Paul; Simeonov, Anton; Dix, David J.; Austin, Christopher P.; Kavlock, Robert J.; Tice, Raymond R.; Xia, Menghang

    2014-01-01

    The U.S. Tox21 program has screened a library of approximately 10,000 (10K) environmental chemicals and drugs in three independent runs for estrogen receptor alpha (ERα) agonist and antagonist activity using two types of ER reporter gene cell lines, one with an endogenous full length ERα (ER-luc; BG1 cell line) and the other with a transfected partial receptor consisting of the ligand binding domain (ER-bla; ERα β-lactamase cell line), in a quantitative high-throughput screening (qHTS) format. The ability of the two assays to correctly identify ERα agonists and antagonists was evaluated using a set of 39 reference compounds with known ERα activity. Although both assays demonstrated adequate (i.e. >80%) predictivity, the ER-luc assay was more sensitive and the ER-bla assay more specific. The qHTS assay results were compared with results from previously published ERα binding assay data and showed >80% consistency. Actives identified from both the ER-bla and ER-luc assays were analyzed for structure-activity relationships (SARs) revealing known and potentially novel ERα active structure classes. The results demonstrate the feasibility of qHTS to identify environmental chemicals with the potential to interact with the ERα signaling pathway and the two different assay formats improve the confidence in correctly identifying these chemicals. PMID:25012808

  11. Endoplasmic reticulum stress-mediated autophagy contributes to bluetongue virus infection via the PERK-eIF2α pathway.

    PubMed

    Lv, Shuang; Sun, En-Cheng; Xu, Qing-Yuan; Zhang, Ji-Kai; Wu, Dong-Lai

    2015-10-23

    Bluetongue virus (BTV) is an important pathogen of wild and domestic ruminants. We have previously reported that BTV1 infection induced autophagy for its own benefit, but how this occurs remains unclear. Here, the classical autophagy features including autophagsomes formation, GFP-LC3 dots and LC3-II conversation were shown in BTV1-infected cells, we also found the endoplasmic reticulum (ER) stress was triggered by BTV1 infection, which was demonstrated by the increased transcription level of the ER stress marker GRP78 and the expanded morphology of ER. During ER stress, PERK and eIF2α phosphorylation increased along with BTV1 infection, consistent with the elevated LC3 level, indicating that the PERK pathway of the unfolded protein response (UPR) was activated. In addition, both the blockage of PERK by GSK2656157 or knockdown of eIF2α by siRNA reduced the level of LC3, which suggested that the PERK-eIF2α pathway contributed to autophagy induced by BTV1. Furthermore, inactivation of PERK or silencing of eIF2α both significantly reduced the expression of VP2 protein and the viral yields in the supernatants. In sum, these data suggest that ER stress mediates autophagy via the PERK-eIF2α pathway and contributes to BTV1 replication, thus offering new insight into the molecular mechanisms of the BTV-host interaction.

  12. The E3 Ubiquitin Ligase IDOL Induces the Degradation of the Low Density Lipoprotein Receptor Family Members VLDLR and ApoER2*

    PubMed Central

    Hong, Cynthia; Duit, Sarah; Jalonen, Pilvi; Out, Ruud; Scheer, Lilith; Sorrentino, Vincenzo; Boyadjian, Rima; Rodenburg, Kees W.; Foley, Edan; Korhonen, Laura; Lindholm, Dan; Nimpf, Johannes; van Berkel, Theo J. C.; Tontonoz, Peter; Zelcer, Noam

    2010-01-01

    We have previously identified the E3 ubiquitin ligase-inducible degrader of the low density lipoprotein receptor (LDLR) (Idol) as a post-translational modulator of LDLR levels. Idol is a direct target for regulation by liver X receptors (LXRs), and its expression is responsive to cellular sterol status independent of the sterol-response element-binding proteins. Here we demonstrate that Idol also targets two closely related LDLR family members, VLDLR and ApoE receptor 2 (ApoER2), proteins implicated in both neuronal development and lipid metabolism. Idol triggers ubiquitination of the VLDLR and ApoER2 on their cytoplasmic tails, leading to their degradation. We further show that the level of endogenous VLDLR is sensitive to cellular sterol content, Idol expression, and activation of the LXR pathway. Pharmacological activation of the LXR pathway in mice leads to increased Idol expression and to decreased Vldlr levels in vivo. Finally, we establish an unexpected functional link between LXR and Reelin signaling. We demonstrate that LXR activation results in decreased Reelin binding to VLDLR and reduced Dab1 phosphorylation. The identification of VLDLR and ApoER2 as Idol targets suggests potential roles for this LXR-inducible E3 ligase in the central nervous system in addition to lipid metabolism. PMID:20427281

  13. Effects of excess silicon on the 1540 nm Er3+ luminescence in silicon rich oxynitride films

    NASA Astrophysics Data System (ADS)

    Xu, Lingbo; Jin, Lu; Li, Dongsheng; Yang, Deren

    2013-08-01

    Indirect excitation of Er3+ ions via energy transfer from silicon nano-clusters (Si-NCs) is demonstrated in silicon rich oxynitride films with different Si excess concentrations. Excess Si shows competitive effects on Er3+ luminescence. It could enhance the Er3+ emission efficiency while it degrades the energy transfer efficiency and density of optically active Er3+ ions at the same time. Furthermore, coalescence of Si-NCs is observed in the samples with high Si excess concentrations, reducing the density of sensitizers and their coupling with Er.

  14. Macroautophagy is regulated by the UPR-mediator CHOP and accentuates the phenotype of SBMA mice.

    PubMed

    Yu, Zhigang; Wang, Adrienne M; Adachi, Hiroaki; Katsuno, Masahisa; Sobue, Gen; Yue, Zhenyu; Robins, Diane M; Lieberman, Andrew P

    2011-10-01

    Altered protein homeostasis underlies degenerative diseases triggered by misfolded proteins, including spinal and bulbar muscular atrophy (SBMA), a neuromuscular disorder caused by a CAG/glutamine expansion in the androgen receptor. Here we show that the unfolded protein response (UPR), an ER protein quality control pathway, is induced in skeletal muscle from SBMA patients, AR113Q knock-in male mice, and surgically denervated wild-type mice. To probe the consequence of UPR induction, we deleted CHOP (C/EBP homologous protein), a transcription factor induced following ER stress. CHOP deficiency accentuated atrophy in both AR113Q and surgically denervated muscle through activation of macroautophagy, a lysosomal protein quality control pathway. Conversely, impaired autophagy due to Beclin-1 haploinsufficiency decreased muscle wasting and extended lifespan of AR113Q males, producing a significant and unexpected amelioration of the disease phenotype. Our findings highlight critical cross-talk between the UPR and macroautophagy, and they indicate that autophagy activation accentuates aspects of the SBMA phenotype.

  15. Analysis of the miRNA-mRNA-lncRNA networks in ER+ and ER- breast cancer cell lines.

    PubMed

    Wu, Qian; Guo, Li; Jiang, Fei; Li, Lei; Li, Zhong; Chen, Feng

    2015-12-01

    Recently, rapid advances in bioinformatics analysis have expanded our understanding of the transcriptome to a genome-wide level. miRNA-mRNA-lncRNA interactions have been shown to play critical regulatory role in cancer biology. In this study, we discussed the use of an integrated systematic approach to explore new facets of the oestrogen receptor (ER)-regulated transcriptome. The identification of RNAs that are related to the expression status of the ER may be useful in clinical therapy and prognosis. We used a network modelling strategy. First, microarray expression profiling of mRNA, lncRNA and miRNA was performed in MCF-7 (ER-positive) and MDA-MB-231 cells (ER- negative). A co-expression network was then built using co-expression relationships of the differentially expressed mRNAs and lncRNAs. Finally, the selected miRNA-mRNA network was added to the network. The key miRNA-mRNA-lncRNA interaction can be inferred from the network. The mRNA and non-coding RNA expression profiles of the cells with different ER phenotypes were distinct. Among the aberrantly expressed miRNAs, the expression levels of miR-19a-3p, miR-19b-3p and miR-130a-3p were much lower in the MCF-7 cells, whereas that of miR-148b-3p was much higher. In a cluster of miR-17-92, the expression levels of six of seven miRNAs were lower in the MCF-7 cells, in addition to miR-20b in the miR-106a-363 cluster. However, the levels of all the miRNAs in the miR-106a-25 cluster were higher in the MCF-7 cells. In the co-expression networking, CD74 and FMNL2 gene which is involved in the immune response and metastasis, respectively, had a stronger correlation with ER. Among the aberrantly expressed lncRNAs, lncRNA-DLEU1 was highly expressed in the MCF-7 cells. A statistical analysis revealed that there was a co-expression relationship between ESR1 and lncRNA-DLEU1. In addition, miR-19a and lncRNA-DLEU1 are both located on the human chromosome 13q. We speculate that miR-19a might be co-expressed with lncRNA-DLEU1

  16. Subverting ER-stress towards apoptosis by nelfinavir and curcumin coexposure augments docetaxel efficacy in castration resistant prostate cancer cells.

    PubMed

    Mathur, Aditi; Abd Elmageed, Zakaria Y; Liu, Xichun; Kostochka, Mikhail L; Zhang, Haitao; Abdel-Mageed, Asim B; Mondal, Debasis

    2014-01-01

    Despite its side-effects, docetaxel (DTX) remains a first-line treatment against castration resistant prostate cancer (CRPC). Therefore, strategies to increase its anti-tumor efficacy and decrease its side effects are critically needed. Targeting of the constitutive endoplasmic reticulum (ER) stress in cancer cells is being investigated as a chemosensitization approach. We hypothesized that the simultaneous induction of ER-stress and suppression of PI3K/AKT survival pathway will be a more effective approach. In a CRPC cell line, C4-2B, we observed significant (p<0.005) enhancement of DTX-induced cy