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Sample records for ssz1 restores endoplasmic

  1. Neuroprotective effect of Salvia sahendica is mediated by restoration of mitochondrial function and inhibition of endoplasmic reticulum stress.

    PubMed

    Shaerzadeh, Fatemeh; Alamdary, Shabnam Zeighamy; Esmaeili, Mohammad Ali; Sarvestani, Nazanin Namazi; Khodagholi, Fariba

    2011-12-01

    Herein, we investigated the protective effect of Salvia sahendica against H(2)O(2)-induced cell death in rat pheochromocytoma (PC12) cells. Our data show that S. sahendica blocks apoptosis pathway by inhibition of cytochrome c release from mitochondria and leakage of calcium from endoplasmic reticulum. It also activates/inactivates two members of Bcl-2 family, Bax and Bcl-2. Bax inhibition and Bcl-2 activation suppress release of cytochrome c from mitochondria that prevents cleavage of caspase-3. Besides S. sahendica suppresses ER stress via attenuation of intracellular levels of calcium. Suppression of ER stress decreased calpain activation and subsequently cleavage of caspase-12. Altogether, these results indicate that S. sahendica protects PC12 cells treated with H(2)O(2) via suppression of upstream factors of apoptosis pathway. While oxidative stress is an early event in Alzheimer disease, it seems that S. sahendica prevents deleterious effects of reactive oxygen species by stabilizing mitochondrial membranes and inhibiting ER stress. PMID:21769643

  2. Endoplasmic motility spectral characteristics in plasmodium of Physarum polycephalum

    NASA Astrophysics Data System (ADS)

    Avsievich, T. I.; Ghaleb, K. E. S.; Frolov, S. V.; Proskurin, S. G.

    2015-03-01

    Spectral Fourier analysis of experimentally acquired velocity time dependencies, V(t), of shuttle endoplasmic motility in an isolated strand of plasmodium of slime mold Physarum Polycephalum has been realized. V(t) registration was performed in normal conditions and after the treatment by respiration inhibitors, which lead to a complete cessation of endoplasmic motion in the strand. Spectral analysis of the velocity time dependences of the endoplasm allows obtaining two distinct harmonic components in the spectra. Their ratio appeared to be constant in all cases, ν2/ν1=1.97±0.17. After the inhibitors are washed out respiratory system becomes normal, gradually restoring the activity of both harmonic oscillatory sources with time. Simulated velocity time dependences correspond to experimental data with good accuracy.

  3. Endoplasmic Reticulum Stress and Type 2 Diabetes

    PubMed Central

    Back, Sung Hoon; Kaufman, Randal J.

    2013-01-01

    Given the functional importance of the endoplasmic reticulum (ER), an organelle that performs folding, modification, and trafficking of secretory and membrane proteins to the Golgi compartment, the maintenance of ER homeostasis in insulin-secreting β-cells is very important. When ER homeostasis is disrupted, the ER generates adaptive signaling pathways, called the unfolded protein response (UPR), to maintain homeostasis of this organelle. However, if homeostasis fails to be restored, the ER initiates death signaling pathways. New observations suggest that both chronic hyperglycemia and hyperlipidemia, known as important causative factors of type 2 diabetes (T2D), disrupt ER homeostasis to induce unresolvable UPR activation and β-cell death. This review examines how the UPR pathways, induced by high glucose and free fatty acids (FFAs), interact to disrupt ER function and cause β-cell dysfunction and death. PMID:22443930

  4. BIOGENESIS OF ENDOPLASMIC RETICULUM MEMBRANES

    PubMed Central

    Dallner, Gustav; Siekevitz, Philip; Palade, George E.

    1966-01-01

    The development of the endoplasmic reticulum of rat hepatocytes was studied during a period of rapid cell differentiation, i.e., from 3 days before to 8 days after birth. Before birth, the ER increases in volume, remaining predominantly rough surfaced; after birth, the increase continues but affects mainly the smooth-surfaced part of the system. These changes are reflected in variations of the RNA/protein and PLP/protein ratios of microsomal fractions: the first decreases, while the second increases, with age. The analysis of microsomal membranes and of microsomal lipids indicates that the PLP/protein ratio, the distribution of phospholipids, and the rate of P32 incorporation into these phospholipids show little variation over the period examined and are comparable to values found in adult liver. Fatty acid composition of total phosphatides undergoes, however, drastic changes after birth. During the period of rapid ER development in vivo incorporation of leucine-C14 and glycerol-C14 into the proteins and lipids of microsomal membranes is higher in the rough-than in the smooth-surfaced microsomes, for the first hours after the injection of the label; later on (∼10 hr) the situation is reversed. These results strongly suggest that new membrane is synthesized in the rough ER and subsequently transferred to the smooth ER. PMID:5966178

  5. An adaptable standard for protein export from the endoplasmic reticulum.

    PubMed

    Wiseman, R Luke; Powers, Evan T; Buxbaum, Joel N; Kelly, Jeffery W; Balch, William E

    2007-11-16

    To provide an integrated view of endoplasmic reticulum (ER) function in protein export, we have described the interdependence of protein folding energetics and the adaptable biology of cellular protein folding and transport through the exocytic pathway. A simplified treatment of the protein homeostasis network and a formalism for how this network of competing pathways interprets protein folding kinetics and thermodynamics provides a framework for understanding cellular protein trafficking. We illustrate how folding and misfolding energetics, in concert with the adjustable biological capacities of the folding, degradation, and export pathways, collectively dictate an adaptable standard for protein export from the ER. A model of folding for export (FoldEx) establishes that no single feature dictates folding and transport efficiency. Instead, a network view provides insight into the basis for cellular diversity, disease origins, and protein homeostasis, and predicts strategies for restoring protein homeostasis in protein-misfolding diseases.

  6. River restoration

    NASA Astrophysics Data System (ADS)

    Wohl, Ellen; Angermeier, Paul L.; Bledsoe, Brian; Kondolf, G. Mathias; Macdonnell, Larry; Merritt, David M.; Palmer, Margaret A.; Poff, N. Leroy; Tarboton, David

    2005-10-01

    River restoration is at the forefront of applied hydrologic science. However, many river restoration projects are conducted with minimal scientific context. We propose two themes around which a research agenda to advance the scientific basis for river restoration can be built. First, because natural variability is an inherent feature of all river systems, we hypothesize that restoration of process is more likely to succeed than restoration aimed at a fixed end point. Second, because physical, chemical, and biological processes are interconnected in complex ways across watersheds and across timescales, we hypothesize that restoration projects are more likely to be successful in achieving goals if undertaken in the context of entire watersheds. To achieve restoration objectives, the science of river restoration must include (1) an explicit recognition of the known complexities and uncertainties, (2) continued development of a theoretical framework that enables us to identify generalities among river systems and to ask relevant questions, (3) enhancing the science and use of restoration monitoring by measuring the most effective set of variables at the correct scales of measurement, (4) linking science and implementation, and (5) developing methods of restoration that are effective within existing constraints. Key limitations to river restoration include a lack of scientific knowledge of watershed-scale process dynamics, institutional structures that are poorly suited to large-scale adaptive management, and a lack of political support to reestablish delivery of the ecosystem amenities lost through river degradation. This paper outlines an approach for addressing these shortcomings.

  7. Endoplasmic reticulum stress in liver disease.

    PubMed

    Malhi, Harmeet; Kaufman, Randal J

    2011-04-01

    The unfolded protein response (UPR) is activated upon the accumulation of misfolded proteins in the endoplasmic reticulum (ER) that are sensed by the binding immunoglobulin protein (BiP)/glucose-regulated protein 78 (GRP78). The accumulation of unfolded proteins sequesters BiP so it dissociates from three ER-transmembrane transducers leading to their activation. These transducers are inositol requiring (IRE) 1α, PKR-like ER kinase (PERK), and activating transcription factor (ATF) 6α. PERK phosphorylates eukaryotic initiation factor 2 alpha (eIF2α) resulting in global mRNA translation attenuation, and concurrently selectively increases the translation of several mRNAs, including the transcription factor ATF4, and its downstream target CHOP. IRE1α has kinase and endoribonuclease (RNase) activities. IRE1α autophosphorylation activates the RNase activity to splice XBP1 mRNA, to produce the active transcription factor sXBP1. IRE1α activation also recruits and activates the stress kinase JNK. ATF6α transits to the Golgi compartment where it is cleaved by intramembrane proteolysis to generate a soluble active transcription factor. These UPR pathways act in concert to increase ER content, expand the ER protein folding capacity, degrade misfolded proteins, and reduce the load of new proteins entering the ER. All of these are geared toward adaptation to resolve the protein folding defect. Faced with persistent ER stress, adaptation starts to fail and apoptosis occurs, possibly mediated through calcium perturbations, reactive oxygen species, and the proapoptotic transcription factor CHOP. The UPR is activated in several liver diseases; including obesity associated fatty liver disease, viral hepatitis, and alcohol-induced liver injury, all of which are associated with steatosis, raising the possibility that ER stress-dependent alteration in lipid homeostasis is the mechanism that underlies the steatosis. Hepatocyte apoptosis is a pathogenic event in several liver

  8. Studies on the Endoplasmic Reticulum

    PubMed Central

    Porter, Keith R.; Machado, Raul D.

    1960-01-01

    Cells of onion and garlic root tips were examined under the electron and phase contrast microscopes after fixation in KMnO4. Special attention was focused on the distribution and behavior of the endoplasmic reticulum (ER) during the several phases of mitosis. Slender profiles, recognized as sections through thin lamellar units of the ER (most prominent in KMnO4-fixed material), are distributed more or less uniformly in the cytoplasm of interphase cells and show occasional continuity with the nuclear envelope. In late prophase the nuclear envelope breaks down and its remnants plus cytoplasmic elements of the ER, which are morphologically identical, surround the spindle in a zone from which mitochondria, etc., are excluded. During metaphase these ER elements persist and concentrate as two separate systems in the polar caps or zones of the spindle. At about this same time they begin to proliferate and to invade the ends of the spindle. The invading lamellar units form drape-like partitions between the anaphase chromosomes. In late anaphase, their advancing margins reach the middle zone of the spindle and begin to fray out. Finally, in telophase, while elements of the ER in the poles of the spindle coalesce around the chromosomes to form the new envelope, the advancing edges of those in the middle zone reticulate at the level of the equator to form a close lattice of tubular elements. Within this, which is identified as the phragmoplast, the earliest signs of the cell plate appear in the form of small vesicles. These subsequently grow and fuse to complete the separation of the two protoplasts. Other morphological units apparently participating in mitosis are described. Speculation is provided on the equal division or not of the nuclear envelope and the contribution the envelope fragments make to the ER of the new cell. PMID:14434278

  9. Potassium fluxes across the endoplasmic reticulum and their role in endoplasmic reticulum calcium homeostasis.

    PubMed

    Kuum, Malle; Veksler, Vladimir; Kaasik, Allen

    2015-07-01

    There are a number of known and suspected channels and exchangers in the endoplasmic reticulum that may participate in potassium flux across its membrane. They include trimeric intracellular cation channels permeable for potassium, ATP-sensitive potassium channels, calcium-activated potassium channels and the potassium-hydrogen exchanger. Apart from trimeric intracellular cation channels, which are specific to the endoplasmic reticulum, other potassium channels are also expressed in the plasma membrane and/or mitochondria, and their specific role in the endoplasmic reticulum has not yet been fully established. In addition to these potassium-selective channels, the ryanodine receptor and, potentially, the inositol 1,4,5-trisphosphate receptor are permeable to potassium ions. Also, the role of potassium fluxes across the endoplasmic reticulum membrane has remained elusive. It has been proposed that their main role is to balance the charge movement that occurs during calcium release and uptake from or to the endoplasmic reticulum. This review aims to summarize current knowledge on endoplasmic reticulum potassium channels and fluxes and their potential role in endoplasmic reticulum calcium uptake and release.

  10. Endoplasmic reticulum aminopeptidases: biochemistry, physiology and pathology.

    PubMed

    Hattori, Akira; Tsujimoto, Masafumi

    2013-09-01

    The human endoplasmic reticulum aminopeptidase (ERAP) 1 and 2 proteins were initially identified as homologues of human placental leucine aminopeptidase/insulin-regulated aminopeptidase. They are categorized as a unique class of proteases based on their subcellular localization on the luminal side of the endoplasmic reticulum. ERAPs play an important role in the N-terminal processing of the antigenic precursors that are presented on the major histocompatibility complex (MHC) class I molecules. ERAPs are also implicated in the regulation of a wide variety of physiological phenomena and pathogenic conditions. In this review, the current knowledge on ERAPs is summarized.

  11. Preservation & Restoration.

    ERIC Educational Resources Information Center

    Online-Offline, 2000

    2000-01-01

    This theme issue on preservation and restoration presents selected resources for elementary and secondary education that include Web sites, CD-ROM and software, videos, books, magazines, and professional resources as well as classroom activities. Age levels are specified for most materials. I Sidebars discuss restoring a masterpiece, a bug's life,…

  12. Endoplasmic Reticulum Stress and Associated ROS

    PubMed Central

    Zeeshan, Hafiz Maher Ali; Lee, Geum Hwa; Kim, Hyung-Ryong; Chae, Han-Jung

    2016-01-01

    The endoplasmic reticulum (ER) is a fascinating network of tubules through which secretory and transmembrane proteins enter unfolded and exit as either folded or misfolded proteins, after which they are directed either toward other organelles or to degradation, respectively. The ER redox environment dictates the fate of entering proteins, and the level of redox signaling mediators modulates the level of reactive oxygen species (ROS). Accumulating evidence suggests the interrelation of ER stress and ROS with redox signaling mediators such as protein disulfide isomerase (PDI)-endoplasmic reticulum oxidoreductin (ERO)-1, glutathione (GSH)/glutathione disuphide (GSSG), NADPH oxidase 4 (Nox4), NADPH-P450 reductase (NPR), and calcium. Here, we reviewed persistent ER stress and protein misfolding-initiated ROS cascades and their significant roles in the pathogenesis of multiple human disorders, including neurodegenerative diseases, diabetes mellitus, atherosclerosis, inflammation, ischemia, and kidney and liver diseases. PMID:26950115

  13. Endoplasmic reticulum stress: a novel mechanism and therapeutic target for cardiovascular diseases

    PubMed Central

    Liu, Mei-qing; Chen, Zhe; Chen, Lin-xi

    2016-01-01

    Endoplasmic reticulum is a principal organelle responsible for folding, post-translational modifications and transport of secretory, luminal and membrane proteins, thus palys an important rale in maintaining cellular homeostasis. Endoplasmic reticulum stress (ERS) is a condition that is accelerated by accumulation of unfolded/misfolded proteins after endoplasmic reticulum environment disturbance, triggered by a variety of physiological and pathological factors, such as nutrient deprivation, altered glycosylation, calcium depletion, oxidative stress, DNA damage and energy disturbance, etc. ERS may initiate the unfolded protein response (UPR) to restore cellular homeostasis or lead to apoptosis. Numerous studies have clarified the link between ERS and cardiovascular diseases. This review focuses on ERS-associated molecular mechanisms that participate in physiological and pathophysiological processes of heart and blood vessels. In addition, a number of drugs that regulate ERS was introduced, which may be used to treat cardiovascular diseases. This review may open new avenues for studying the pathogenesis of cardiovascular diseases and discovering novel drugs targeting ERS. PMID:26838072

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

    PubMed

    Huang, Liu; Xie, Hong; Liu, Hao

    2014-01-01

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

  15. 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.

  16. Diverse roles of endoplasmic reticulum stress sensors in bacterial infection.

    PubMed

    Pillich, Helena; Loose, Maria; Zimmer, Klaus-Peter; Chakraborty, Trinad

    2016-12-01

    Bacterial infection often leads to cellular damage, primarily marked by loss of cellular integrity and cell death. However, in recent years, it is being increasingly recognized that, in individual cells, there are graded responses collectively termed cell-autonomous defense mechanisms that induce cellular processes designed to limit cell damage, enable repair, and eliminate bacteria. Many of these responses are triggered not by detection of a particular bacterial effector or ligand but rather by their effects on key cellular processes and changes in homeostasis induced by microbial effectors when recognized. These in turn lead to a decrease in essential cellular functions such as protein translation or mitochondrial respiration and the induction of innate immune responses that may be specific to the cellular deficit induced. These processes are often associated with specific cell compartments, e.g., the endoplasmic reticulum (ER). Under non-infection conditions, these systems are generally involved in sensing cellular stress and in inducing and orchestrating the subsequent cellular response. Thus, perturbations of ER homeostasis result in accumulation of unfolded proteins which are detected by ER stress sensors in order to restore the normal condition. The ER is also important during bacterial infection, and bacterial effectors that activate the ER stress sensors have been discovered. Increasing evidence now indicate that bacteria have evolved strategies to differentially activate different arms of ER stress sensors resulting in specific host cell response. In this review, we will describe the mechanisms used by bacteria to activate the ER stress sensors and discuss their role during infection.

  17. Endoplasmic reticulum stress response in yeast and humans

    PubMed Central

    Wu, Haoxi; Ng, Benjamin S. H.; Thibault, Guillaume

    2014-01-01

    Stress pathways monitor intracellular systems and deploy a range of regulatory mechanisms in response to stress. One of the best-characterized pathways, the UPR (unfolded protein response), is an intracellular signal transduction pathway that monitors ER (endoplasmic reticulum) homoeostasis. Its activation is required to alleviate the effects of ER stress and is highly conserved from yeast to human. Although metazoans have three UPR outputs, yeast cells rely exclusively on the Ire1 (inositol-requiring enzyme-1) pathway, which is conserved in all Eukaryotes. In general, the UPR program activates hundreds of genes to alleviate ER stress but it can lead to apoptosis if the system fails to restore homoeostasis. In this review, we summarize the major advances in understanding the response to ER stress in Sc (Saccharomyces cerevisiae), Sp (Schizosaccharomyces pombe) and humans. The contribution of solved protein structures to a better understanding of the UPR pathway is discussed. Finally, we cover the interplay of ER stress in the development of diseases. PMID:24909749

  18. Endoplasmic Reticulum Stress Interacts With Inflammation in Human Diseases

    PubMed Central

    Cao, Stewart Siyan; Luo, Katherine L.; Shi, Lynn

    2015-01-01

    The endoplasmic reticulum is a critical organelle for normal cell function and homeostasis. Disturbed protein folding process in the ER, termed ER stress, leads to the activation of unfolded protein response (UPR) that encompasses a complex network of intracellular signaling pathways. The UPR can either restore ER homeostasis or activate pro-apoptotic pathways depending on specific insults, intensity and duration of the stress, and cell types. ER stress and the UPR have recently been linked to inflammation in a variety of human pathologies including autoimmune diseases, infection, neurodegenerative disease, and metabolic disorders. In the cell, ER stress and inflammatory signaling share extensive regulators and effectors in a broad spectrum of biological processes. In spite of different etiologies, the two signaling pathways were shown to form a vicious cycle in exacerbating cellular dysfunction and causing apoptosis in many cells and tissues. However, the interaction between ER stress and inflammation in many of these diseases remains elusive. Further understanding of those issues may enable the development of novel therapies that spontaneously target these pathogenic pathways. PMID:26201832

  19. Natural restoration

    SciTech Connect

    Kamlet, K.S.

    1993-02-01

    After a company pays millions of dollars to clean up contaminated site, its liability may not be over. It may have to spend tens of millions more to restore damaged natural resources under an oft-overlooked Superfund program. Examples of liability are cited in this report from the Exxon Valdez oil spill and a pcb leak which contaminated a harbor.

  20. Restoring Ancestral Language, Restoring Identity.

    ERIC Educational Resources Information Center

    Bannon, Kay T.

    1999-01-01

    Describes the Cherokee Language Renewal Program that was designed to help Cherokee elementary school children learn to function in the dominant culture without sacrificing their own cultural heritage. Explains how the program got started, and reports on how it helps restore a cultural identify to a people who are at risk of losing their identity.…

  1. Restoration Process

    NASA Technical Reports Server (NTRS)

    1979-01-01

    In the accompanying photos, a laboratory technician is restoring the once-obliterated serial number of a revolver. The four-photo sequence shows the gradual progression from total invisibility to clear readability. The technician is using a new process developed in an applications engineering project conducted by NASA's Lewis Research Center in conjunction with Chicago State University. Serial numbers and other markings are frequently eliminated from metal objects to prevent tracing ownership of guns, motor vehicles, bicycles, cameras, appliances and jewelry. To restore obliterated numbers, crime laboratory investigators most often employ a chemical etching technique. It is effective, but it may cause metal corrosion and it requires extensive preparatory grinding and polishing. The NASA-Chicago State process is advantageous because it can be applied without variation to any kind of metal, it needs no preparatory work and number recovery can be accomplished without corrosive chemicals; the liquid used is water.

  2. 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

  3. Protein Translocation across the Rough Endoplasmic Reticulum

    PubMed Central

    Mandon, Elisabet C.; Trueman, Steven F.; Gilmore, Reid

    2013-01-01

    The rough endoplasmic reticulum is a major site of protein biosynthesis in all eukaryotic cells, serving as the entry point for the secretory pathway and as the initial integration site for the majority of cellular integral membrane proteins. The core components of the protein translocation machinery have been identified, and high-resolution structures of the targeting components and the transport channel have been obtained. Research in this area is now focused on obtaining a better understanding of the molecular mechanism of protein translocation and membrane protein integration. PMID:23251026

  4. [Endoplasmic reticulum stress response in osteogenesis].

    PubMed

    Saito, Atsushi; Imaizumi, Kazunori

    2013-11-01

    Various cellular conditions such as synthesis of abundant proteins, expressions of mutant proteins and oxidative stress lead to accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) lumen. This type of stress is called ER stress. The excessive ER stress causes cellular damages followed by apoptosis. When ER stress occurs, cells are activated ER stress response (unfolded protein response) to avoid cellular damages. Recently, it has been clear that ER stress response plays crucial roles not only in cell survival after ER stress but also in regulating various cellular functions and tissue formations. In particular, ER stress and ER stress response regulate protein quality control, secretory protein production, and smooth secretion of proteins in the cells such as osteoblasts which synthesize and secrete enormous matrix proteins.

  5. Membrane Protein Insertion at the Endoplasmic Reticulum

    PubMed Central

    Shao, Sichen; Hegde, Ramanujan S.

    2014-01-01

    Integral membrane proteins of the cell surface and most intracellular compartments of eukaryotic cells are assembled at the endoplasmic reticulum. Two highly conserved and parallel pathways mediate membrane protein targeting to and insertion into this organelle. The classical cotranslational pathway, utilized by most membrane proteins, involves targeting by the signal recognition particle followed by insertion via the Sec61 translocon. A more specialized posttranslational pathway, employed by many tail-anchored membrane proteins, is composed of entirely different factors centered around a cytosolic ATPase termed TRC40 or Get3. Both of these pathways overcome the same biophysical challenges of ferrying hydrophobic cargo through an aqueous milieu, selectively delivering it to one among several intracellular membranes and asymmetrically integrating its transmembrane domain(s) into the lipid bilayer. Here, we review the conceptual and mechanistic themes underlying these core membrane protein insertion pathways, the complexities that challenge our understanding, and future directions to over-come these obstacles. PMID:21801011

  6. Endoplasmic-Reticulum Calcium Depletion and Disease

    PubMed Central

    Mekahli, Djalila; Bultynck, Geert; Parys, Jan B.; De Smedt, Humbert; Missiaen, Ludwig

    2011-01-01

    The endoplasmic reticulum (ER) as an intracellular Ca2+ store not only sets up cytosolic Ca2+ signals, but, among other functions, also assembles and folds newly synthesized proteins. Alterations in ER homeostasis, including severe Ca2+ depletion, are an upstream event in the pathophysiology of many diseases. On the one hand, insufficient release of activator Ca2+ may no longer sustain essential cell functions. On the other hand, loss of luminal Ca2+ causes ER stress and activates an unfolded protein response, which, depending on the duration and severity of the stress, can reestablish normal ER function or lead to cell death. We will review these various diseases by mainly focusing on the mechanisms that cause ER Ca2+ depletion. PMID:21441595

  7. Endoplasmic reticulum stress responses in plants.

    PubMed

    Howell, Stephen H

    2013-01-01

    Endoplasmic reticulum (ER) stress is of considerable interest to plant biologists because it occurs in plants subjected to adverse environmental conditions. ER stress responses mitigate the damage caused by stress and confer levels of stress tolerance to plants. ER stress is activated by misfolded proteins that accumulate in the ER under adverse environmental conditions. Under these conditions, the demand for protein folding exceeds the capacity of the system, which sets off the unfolded protein response (UPR). Two arms of the UPR signaling pathway have been described in plants: one that involves two ER membrane-associated transcription factors (bZIP17 and bZIP28) and another that involves a dual protein kinase (RNA-splicing factor IRE1) and its target RNA (bZIP60). Under mild or short-term stress conditions, signaling from IRE1 activates autophagy, a cell survival response. But under severe or chronic stress conditions, ER stress can lead to cell death.

  8. Endoplasmic reticulum: ER stress regulates mitochondrial bioenergetics.

    PubMed

    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

    2012-01-01

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

  9. Nonvesicular Lipid Transfer from the Endoplasmic Reticulum

    PubMed Central

    Lev, Sima

    2012-01-01

    The transport of lipids from their synthesis site at the endoplasmic reticulum (ER) to different target membranes could be mediated by both vesicular and nonvesicular transport mechanisms. Nonvesicular lipid transport appears to be the major transport route of certain lipid species, and could be mediated by either spontaneous lipid transport or by lipid-transfer proteins (LTPs). Although nonvesicular lipid transport has been extensively studied for more than four decades, its underlying mechanism, advantage and regulation, have not been fully explored. In particular, the function of LTPs and their involvement in intracellular lipid movement remain largely controversial. In this article, we describe the pathways by which lipids are synthesized at the ER and delivered to different cellular membranes, and discuss the role of LTPs in lipid transport both in vitro and in intact cells. PMID:23028121

  10. Endoplasmic Reticulum Stress and Ethanol Neurotoxicity.

    PubMed

    Yang, Fanmuyi; Luo, Jia

    2015-10-14

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

  11. Endoplasmic Reticulum Stress and Ethanol Neurotoxicity

    PubMed Central

    Yang, Fanmuyi; Luo, Jia

    2015-01-01

    Ethanol abuse affects virtually all organ systems and the central nervous system (CNS) is particularly vulnerable to excessive ethanol exposure. Ethanol exposure causes profound damages to both the adult and developing brain. Prenatal ethanol exposure induces fetal alcohol spectrum disorders (FASD) which is associated with mental retardation and other behavioral deficits. A number of potential mechanisms have been proposed for ethanol-induced brain damage; these include the promotion of neuroinflammation, interference with signaling by neurotrophic factors, induction of oxidative stress, modulation of retinoid acid signaling, and thiamine deficiency. The endoplasmic reticulum (ER) regulates posttranslational protein processing and transport. The accumulation of unfolded or misfolded proteins in the ER lumen triggers ER stress and induces unfolded protein response (UPR) which are mediated by three transmembrane ER signaling proteins: pancreatic endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1 (IRE1), and activating transcription factor 6 (ATF6). UPR is initiated to protect cells from overwhelming ER protein loading. However, sustained ER stress may result in cell death. ER stress has been implied in various CNS injuries, including brain ischemia, traumatic brain injury, and aging-associated neurodegeneration, such as Alzheimer’s disease (AD), Huntington’s disease (HD), Amyotrophic lateral sclerosis (ALS), and Parkinson’s disease (PD). However, effects of ethanol on ER stress in the CNS receive less attention. In this review, we discuss recent progress in the study of ER stress in ethanol-induced neurotoxicity. We also examine the potential mechanisms underlying ethanol-mediated ER stress and the interaction among ER stress, oxidative stress and autophagy in the context of ethanol neurotoxicity. PMID:26473940

  12. Activation of autophagy by unfolded proteins during endoplasmic reticulum stress.

    PubMed

    Yang, Xiaochen; Srivastava, Renu; Howell, Stephen H; Bassham, Diane C

    2016-01-01

    Endoplasmic reticulum stress is defined as the accumulation of unfolded proteins in the endoplasmic reticulum, and is caused by conditions such as heat or agents that cause endoplasmic reticulum stress, including tunicamycin and dithiothreitol. Autophagy, a major pathway for degradation of macromolecules in the vacuole, is activated by these stress agents in a manner dependent on inositol-requiring enzyme 1b (IRE1b), and delivers endoplasmic reticulum fragments to the vacuole for degradation. In this study, we examined the mechanism for activation of autophagy during endoplasmic reticulum stress in Arabidopsis thaliana. The chemical chaperones sodium 4-phenylbutyrate and tauroursodeoxycholic acid were found to reduce tunicamycin- or dithiothreitol-induced autophagy, but not autophagy caused by unrelated stresses. Similarly, over-expression of BINDING IMMUNOGLOBULIN PROTEIN (BIP), encoding a heat shock protein 70 (HSP70) molecular chaperone, reduced autophagy. Autophagy activated by heat stress was also found to be partially dependent on IRE1b and to be inhibited by sodium 4-phenylbutyrate, suggesting that heat-induced autophagy is due to accumulation of unfolded proteins in the endoplasmic reticulum. Expression in Arabidopsis of the misfolded protein mimics zeolin or a mutated form of carboxypeptidase Y (CPY*) also induced autophagy in an IRE1b-dependent manner. Moreover, zeolin and CPY* partially co-localized with the autophagic body marker GFP-ATG8e, indicating delivery to the vacuole by autophagy. We conclude that accumulation of unfolded proteins in the endoplasmic reticulum is a trigger for autophagy under conditions that cause endoplasmic reticulum stress. PMID:26616142

  13. Endoplasmic Reticulum Stress in Endometrial Cancer

    PubMed Central

    Ulianich, Luca; Insabato, Luigi

    2014-01-01

    Endometrial cancer (EC) is a common gynecologic malignancy often diagnosed at early stage. In spite of a huge advance in our understanding of EC biology, therapeutic modalities do not have significantly changed over the past 40 years. A restricted number of genes have been reported to be mutated in EC, mediating cell proliferation and invasiveness. However, besides these alterations, few other groups and ourselves recently identified the activation of the unfolded protein response (UPR) and GRP78 increase following endoplasmic reticulum (ER) stress as mechanisms favoring growth and invasion of EC cells. Here, a concise update on currently available data in the field is presented, analyzing the crosstalk between the UPR and the main signaling pathways regulating EC cell proliferation and survival. It is evident that this is a rapidly expanding and promising issue. However, more data are very likely to yield a better understanding on the mechanisms through which EC cells can survive the low oxygen and glucose tumor microenvironment. In this perspective, the UPR and, particularly, GRP78 might constitute a novel target for the treatment of EC in combination with traditional adjuvant therapy. PMID:25593927

  14. Endoplasmic reticulum stress in periimplantation embryos.

    PubMed

    Michalak, Marek; Gye, Myung Chan

    2015-03-01

    Stress coping mechanisms are critical to minimize or overcome damage caused by ever changing environmental conditions. They are designed to promote cell survival. The unfolded protein response (UPR) pathway is mobilized in response to the accumulation of unfolded proteins, ultimately in order to regain endoplasmic reticulum (ER) homeostasis. Various elements of coping responses to ER stress including Perk, Ask1, Bip, Chop, Gadd34, Ire1, Atf4, Atf6, and Xbp1 have been identified and were found to be inducible in oocytes and preimplantation embryos, suggesting that, as a normal part of the cellular adaptive mechanism, these coping responses, including the UPR, play a pivotal role in the development of preimplantation embryos. As such, the UPR-associated molecules and pathways may become useful markers for the potential diagnosis of stress conditions for preimplantation embryos. After implantation, ER stress-induced coping responses become physiologically important for a normal decidual response, placentation, and early organogenesis. Attenuation of ER stress coping responses by tauroursodeoxycholate and salubrinal was effective for prevention of cell death of cultured embryos. Further elucidation of new and relevant ER stress coping responses in periimplantation embryos might contribute to a comprehensive understanding of the regulation of normal development of embryonic development and potentiation of embryonic development in vitro. PMID:25874167

  15. Shaping the endoplasmic reticulum in vitro.

    PubMed

    Ferencz, Csilla-Maria; Guigas, Gernot; Veres, Andreas; Neumann, Brigitte; Stemmann, Olaf; Weiss, Matthias

    2016-09-01

    Organelles in eukaryotic cells often have complex shapes that deviate significantly from simple spheres. A prime example is the endoplasmic reticulum (ER) that forms an extensive network of membrane tubules in many mammalian cell types and in reconstitution assays in vitro. Despite the successful hunt for molecular determinants of ER shape we are still far from having a comprehensive understanding of ER network morphogenesis. Here, we have studied the hitherto neglected influence of the host substrate when reconstituting ER networks in vitro as compared to ER networks in vivo. In culture cells we observed cytoplasm-spanning ER networks with tubules being connected almost exclusively by three-way junctions and segment lengths being narrowly distributed around a mean length of about 1μm. In contrast, networks reconstituted from purified ER microsomes on flat glass or gel substrates of varying stiffness showed significantly broader length distributions with an up to fourfold larger mean length. Self-assembly of ER microsomes on small oil droplets, however, yielded networks that resembled more closely the native ER network of mammalian cells. We conclude from these observations that the ER microsomes' inherent self-assembly capacity is sufficient to support network formation with a native geometry if the influence of the host substrate's surface chemistry becomes negligible. We hypothesize that under these conditions the networks' preference for three-way junctions follows from creating 'starfish-shaped' vesicles when ER microsomes with a protein-induced spontaneous curvature undergo fusion. PMID:27287725

  16. Endoplasmic Reticulum Stress, Genome Damage, and Cancer

    PubMed Central

    Dicks, Naomi; Gutierrez, Karina; Michalak, Marek; Bordignon, Vilceu; Agellon, Luis B.

    2015-01-01

    Endoplasmic reticulum (ER) stress has been linked to many diseases, including cancer. A large body of work has focused on the activation of the ER stress response in cancer cells to facilitate their survival and tumor growth; however, there are some studies suggesting that the ER stress response can also mitigate cancer progression. Despite these contradictions, it is clear that the ER stress response is closely associated with cancer biology. The ER stress response classically encompasses activation of three separate pathways, which are collectively categorized the unfolded protein response (UPR). The UPR has been extensively studied in various cancers and appears to confer a selective advantage to tumor cells to facilitate their enhanced growth and resistance to anti-cancer agents. It has also been shown that ER stress induces chromatin changes, which can also facilitate cell survival. Chromatin remodeling has been linked with many cancers through repression of tumor suppressor and apoptosis genes. Interplay between the classic UPR and genome damage repair mechanisms may have important implications in the transformation process of normal cells into cancer cells. PMID:25692096

  17. Conditions of endoplasmic reticulum stress stimulate lipid droplet formation in Saccharomyces cerevisiae.

    PubMed

    Fei, Weihua; Wang, Han; Fu, Xin; Bielby, Christopher; Yang, Hongyuan

    2009-11-15

    LDs (lipid droplets) are cellular organelles which can be found in nearly all eukaryotic cells. Despite their importance in cell biology, the mechanism underlying LD biogenesis remains largely unknown. In the present study we report that conditions of ER (endoplasmic reticulum) stress stimulate LD formation in Saccharomyces cerevisiae. We found that LDs accumulated in yeast mutants with compromised protein glycosylation or ER-associated protein degradation. Moreover, tunicamycin and Brefeldin A, agents which induce ER stress, were found to stimulate LD formation. In contrast, the restoration of protein glycosylation reduced LD accumulation. Interestingly, enhanced neutral lipids synthesis and LD formation under conditions of ER stress was not dependent on Ire1p. Lastly, we demonstrated that the absence of LDs did not compromise cell viability under ER stress. Our results suggest that although more LDs are produced, LDs are not essential to cell survival under ER stress. PMID:19708857

  18. A flavoprotein oxidase defines a new endoplasmic reticulum pathway for biosynthetic disulphide bond formation.

    PubMed

    Sevier, C S; Cuozzo, J W; Vala, A; Aslund, F; Kaiser, C A

    2001-10-01

    Ero1 and Pdi1 are essential elements of the pathway for the formation of disulphide bonds within the endoplasmic reticulum (ER). By screening for alternative oxidation pathways in Saccharomyces cerevisiae, we identified ERV2 as a gene that when overexpressed can restore viability and disulphide bond formation to an ero1-1 mutant strain. ERV2 encodes a luminal ER protein of relative molecular mass 22,000. Purified recombinant Erv2p is a flavoenzyme that can catalyse O2-dependent formation of disulphide bonds. Erv2p transfers oxidizing equivalents to Pdi1p by a dithiol-disulphide exchange reaction, indicating that the Erv2p-dependent pathway for disulphide bond formation closely parallels that of the previously identified Ero1p-dependent pathway. PMID:11584268

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

    PubMed

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

    2016-01-15

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

  20. ERdj4 and ERdj5 are required for endoplasmic reticulum-associated protein degradation of misfolded surfactant protein C.

    PubMed

    Dong, Mei; Bridges, James P; Apsley, Karen; Xu, Yan; Weaver, Timothy E

    2008-06-01

    Mutations in the SFTPC gene associated with interstitial lung disease in human patients result in misfolding, endoplasmic reticulum (ER) retention, and degradation of the encoded surfactant protein C (SP-C) proprotein. In this study, genes specifically induced in response to transient expression of two disease-associated mutations were identified by microarray analyses. Immunoglobulin heavy chain binding protein (BiP) and two heat shock protein 40 family members, endoplasmic reticulum-localized DnaJ homologues ERdj4 and ERdj5, were significantly elevated and exhibited prolonged and specific association with the misfolded proprotein; in contrast, ERdj3 interacted with BiP, but it did not associate with either wild-type or mutant SP-C. Misfolded SP-C, ERdj4, and ERdj5 coprecipitated with p97/VCP indicating that the cochaperones remain associated with the misfolded proprotein until it is dislocated to the cytosol. Knockdown of ERdj4 and ERdj5 expression increased ER retention and inhibited degradation of misfolded SP-C, but it had little effect on the wild-type protein. Transient expression of ERdj4 and ERdj5 in X-box binding protein 1(-/-) mouse embryonic fibroblasts substantially restored rapid degradation of mutant SP-C proprotein, whereas transfection of HPD mutants failed to rescue SP-C endoplasmic reticulum-associated protein degradation. ERdj4 and ERdj5 promote turnover of misfolded SP-C and this activity is dependent on their ability to stimulate BiP ATPase activity. PMID:18400946

  1. Dysfunction in endoplasmic reticulum-mitochondria crosstalk underlies SIGMAR1 loss of function mediated motor neuron degeneration.

    PubMed

    Bernard-Marissal, Nathalie; Médard, Jean-Jacques; Azzedine, Hamid; Chrast, Roman

    2015-04-01

    Mutations in Sigma 1 receptor (SIGMAR1) have been previously identified in patients with amyotrophic lateral sclerosis and disruption of Sigmar1 in mouse leads to locomotor deficits. However, cellular mechanisms underlying motor phenotypes in human and mouse with disturbed SIGMAR1 function have not been described so far. Here we used a combination of in vivo and in vitro approaches to investigate the role of SIGMAR1 in motor neuron biology. Characterization of Sigmar1(-/-) mice revealed that affected animals display locomotor deficits associated with muscle weakness, axonal degeneration and motor neuron loss. Using primary motor neuron cultures, we observed that pharmacological or genetic inactivation of SIGMAR1 led to motor neuron axonal degeneration followed by cell death. Disruption of SIGMAR1 function in motor neurons disturbed endoplasmic reticulum-mitochondria contacts, affected intracellular calcium signalling and was accompanied by activation of endoplasmic reticulum stress and defects in mitochondrial dynamics and transport. These defects were not observed in cultured sensory neurons, highlighting the exacerbated sensitivity of motor neurons to SIGMAR1 function. Interestingly, the inhibition of mitochondrial fission was sufficient to induce mitochondria axonal transport defects as well as axonal degeneration similar to the changes observed after SIGMAR1 inactivation or loss. Intracellular calcium scavenging and endoplasmic reticulum stress inhibition were able to restore mitochondrial function and consequently prevent motor neuron degeneration. These results uncover the cellular mechanisms underlying motor neuron degeneration mediated by loss of SIGMAR1 function and provide therapeutically relevant insight into motor neuronal diseases.

  2. Nox NADPH Oxidases and the Endoplasmic Reticulum

    PubMed Central

    Araujo, Thaís L.S.; Abrahão, Thalita B.

    2014-01-01

    Abstract Significance: Understanding isoform- and context-specific subcellular Nox reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase compartmentalization allows relevant functional inferences. This review addresses the interplay between Nox NADPH oxidases and the endoplasmic reticulum (ER), an increasingly evident player in redox pathophysiology given its role in redox protein folding and stress responses. Recent Advances: Catalytic/regulatory transmembrane subunits are synthesized in the ER and their processing includes folding, N-glycosylation, heme insertion, p22phox heterodimerization, as shown for phagocyte Nox2. Dual oxidase (Duox) maturation also involves the regulation by ER-resident Duoxa2. The ER is the activation site for some isoforms, typically Nox4, but potentially other isoforms. Such location influences redox/Nox-mediated calcium signaling regulation via ER targets, such as sarcoendoplasmic reticulum calcium ATPase (SERCA). Growing evidence suggests that Noxes are integral signaling elements of the unfolded protein response during ER stress, with Nox4 playing a dual prosurvival/proapoptotic role in this setting, whereas Nox2 enhances proapoptotic signaling. ER chaperones such as protein disulfide isomerase (PDI) closely interact with Noxes. PDI supports growth factor-dependent Nox1 activation and mRNA expression, as well as migration in smooth muscle cells, and PDI overexpression induces acute spontaneous Nox activation. Critical Issues: Mechanisms of PDI effects include possible support of complex formation and RhoGTPase activation. In phagocytes, PDI supports phagocytosis, Nox activation, and redox-dependent interactions with p47phox. Together, the results implicate PDI as possible Nox organizer. Future Directions: We propose that convergence between Noxes and ER may have evolutive roots given ER-related functional contexts, which paved Nox evolution, namely calcium signaling and pathogen killing. Overall, the interplay between

  3. Endoplasmic Reticulum-Associated Degradation and Lipid Homeostasis.

    PubMed

    Stevenson, Julian; Huang, Edmond Y; Olzmann, James A

    2016-07-17

    The endoplasmic reticulum is the port of entry for proteins into the secretory pathway and the site of synthesis for several important lipids, including cholesterol, triacylglycerol, and phospholipids. Protein production within the endoplasmic reticulum is tightly regulated by a cohort of resident machinery that coordinates the folding, modification, and deployment of secreted and integral membrane proteins. Proteins failing to attain their native conformation are degraded through the endoplasmic reticulum-associated degradation (ERAD) pathway via a series of tightly coupled steps: substrate recognition, dislocation, and ubiquitin-dependent proteasomal destruction. The same ERAD machinery also controls the flux through various metabolic pathways by coupling the turnover of metabolic enzymes to the levels of key metabolites. We review the current understanding and biological significance of ERAD-mediated regulation of lipid metabolism in mammalian cells. PMID:27296502

  4. The protein translocation machinery of the endoplasmic reticulum.

    PubMed

    Walter, P; Gilmore, R; Müller, M; Blobel, G

    1982-12-24

    The rough endoplasmic reticulum (r.e.r.) has been postulated to possess a single translation-coupled translocation system (in multiple copies) that effects signal sequence-mediated translocation of all secretory and lysosomal proteins and integration of all integral membrane proteins whose port of entry is the rough endoplasmic reticulum (G. Blobel 1980 Proc. natn. Acad. Sci. U.S.A. 77, 1496-1500). Two proteins have been isolated that are components of the r.e.r. translocation system. Their properties and function in protein translocation across and integration into membranes are discussed. PMID:6131460

  5. Hepatic Xbp1 Gene Deletion Promotes Endoplasmic Reticulum Stress-induced Liver Injury and Apoptosis.

    PubMed

    Olivares, Shantel; Henkel, Anne S

    2015-12-11

    Endoplasmic reticulum (ER) stress activates the unfolded protein response (UPR), a highly conserved signaling cascade that functions to alleviate stress and promote cell survival. If, however, the cell is unable to adapt and restore homeostasis, then the UPR activates pathways that promote apoptotic cell death. The molecular mechanisms governing the critical transition from adaptation and survival to initiation of apoptosis remain poorly understood. We aim to determine the role of hepatic Xbp1, a key mediator of the UPR, in controlling the adaptive response to ER stress in the liver. Liver-specific Xbp1 knockout mice (Xbp1(LKO)) and Xbp1(fl/fl) control mice were subjected to varying levels and durations of pharmacologic ER stress. Xbp1(LKO) and Xbp1(fl/fl) mice showed robust and equal activation of the UPR acutely after induction of ER stress. By 24 h, Xbp1(fl/fl) controls showed complete resolution of UPR activation and no liver injury, indicating successful adaptation to the stress. Conversely, Xbp1(LKO) mice showed ongoing UPR activation associated with progressive liver injury, apoptosis, and, ultimately, fibrosis by day 7 after induction of ER stress. These data indicate that hepatic XBP1 controls the adaptive response of the UPR and is critical to restoring homeostasis in the liver in response to ER stress. PMID:26504083

  6. Restoration technology branch

    USGS Publications Warehouse

    ,

    2007-01-01

    The mission of Leetown Science Center (LSC), Restoration Technology Branch (RTB) is to conduct research needed to restore or protect the chemical, physical and biological integrity of desirable aquatic systems.

  7. Linking restoration ecology with coastal dune restoration

    NASA Astrophysics Data System (ADS)

    Lithgow, D.; Martínez, M. L.; Gallego-Fernández, J. B.; Hesp, P. A.; Flores, P.; Gachuz, S.; Rodríguez-Revelo, N.; Jiménez-Orocio, O.; Mendoza-González, G.; Álvarez-Molina, L. L.

    2013-10-01

    Restoration and preservation of coastal dunes is urgently needed because of the increasingly rapid loss and degradation of these ecosystems because of many human activities. These activities alter natural processes and coastal dynamics, eliminate topographic variability, fragment, degrade or eliminate habitats, reduce diversity and threaten endemic species. The actions of coastal dune restoration that are already taking place span contrasting activities that range from revegetating and stabilizing the mobile substrate, to removing plant cover and increasing substrate mobility. Our goal was to review how the relative progress of the actions of coastal dune restoration has been assessed, according to the ecosystem attributes outlined by the Society of Ecological Restoration: namely, integrity, health and sustainability and that are derived from the ecological theory of succession. We reviewed the peer reviewed literature published since 1988 that is listed in the ISI Web of Science journals as well as additional references, such as key books. We exclusively focused on large coastal dune systems (such as transgressive and parabolic dunefields) located on natural or seminatural coasts. We found 150 articles that included "coastal dune", "restoration" and "revegetation" in areas such as title, keywords and abstract. From these, 67 dealt specifically with coastal dune restoration. Most of the studies were performed in the USA, The Netherlands and South Africa, during the last two decades. Restoration success has been assessed directly and indirectly by measuring one or a few ecosystem variables. Some ecosystem attributes have been monitored more frequently (ecosystem integrity) than others (ecosystem health and sustainability). Finally, it is important to consider that ecological succession is a desirable approach in restoration actions. Natural dynamics and disturbances should be considered as part of the restored system, to improve ecosystem integrity, health and

  8. Isolation of Endoplasmic Reticulum Fractions from Mammary Epithelial Tissue.

    PubMed

    Chanat, Eric; Le Parc, Annabelle; Lahouassa, Hichem; Badaoui, Bouabid

    2016-06-01

    In the mammary glands of lactating animals, the mammary epithelial cells that surround the lumen of the acini produce and secrete copious amounts of milk. Functional differentiation of these mammary epithelial cells depends on the development of high-efficiency secretory pathways, notably for protein and lipid secretion. Protein secretion is a fundamental process common to all animal cells that involves a subset of cellular organelles, including the endoplasmic reticulum and the Golgi apparatus. In contrast, en masse secretion of triglycerides and cholesterol esters in the form of milk fat globules is a unique feature of the mammary epithelial cell. Cytoplasmic lipid droplets, the intracellular precursors of milk fat globules, originate from the endoplasmic reticulum, as do most milk-specific proteins. This organelle is therefore pivotal in the biogenesis of milk components. Fractionation of the cell into its subcellular parts is an approach that has proven very powerful for understanding organelle function and for studying the specific role of an organelle in a given cell activity. Here we describe a method for the purification of both smooth and rough microsomes, the membrane-bound endoplasmic reticulum fragments that form from endoplasmic reticulum domains when cells are broken up, from mammary gland tissue at lactation.

  9. Endoplasmic reticulum stress and proteasomal system in amyotrophic lateral sclerosis.

    PubMed

    Karademir, Betul; Corek, Ceyda; Ozer, Nesrin Kartal

    2015-11-01

    Protein processing including folding, unfolding and degradation is involved in the mechanisms of many diseases. Unfolded protein response and/or endoplasmic reticulum stress are accepted to be the first steps which should be completed via protein degradation. In this direction, proteasomal system and autophagy play important role as the degradation pathways and controlled via complex mechanisms. Amyotrophic lateral sclerosis is a multifactorial neurodegenerative disease which is also known as the most catastrophic one. Mutation of many different genes are involved in the pathogenesis such as superoxide dismutase 1, chromosome 9 open reading frame 72 and ubiquilin 2. These genes are mainly related to the antioxidant defense systems, endoplasmic reticulum stress related proteins and also protein aggregation, degradation pathways and therefore mutation of these genes cause related disorders.This review focused on the role of protein processing via endoplasmic reticulum and proteasomal system in amyotrophic lateral sclerosis which are the main players in the pathology. In this direction, dysfunction of endoplasmic reticulum associated degradation and related cell death mechanisms that are autophagy/apoptosis have been detailed.

  10. Rheological properties of living cytoplasm: endoplasm of Physarum plasmodium.

    PubMed

    Sato, M; Wong, T Z; Allen, R D

    1983-10-01

    Magnetic sphere viscoelastometry, video microscopy, and the Kamiya double chamber method (Kamiya, N., 1940, Science [Wash. DC], 92:462-463.) have been combined in an optical and rheological investigation of the living endoplasm of Physarum polycephalum. The rheological properties examined were yield stress, viscosity (as a function of shear), and elasticity. These parameters were evaluated in directions perpendicular; (X) and parallel (Y) to the plasmodial vein. Known magnetic forces were used for measurements in the X direction, while the falling ball technique was used in the Y direction (Cygan, D.A., and B. Caswell, 1971, Trans. Soc. Rheol. 15:663-683; MacLean-Fletcher, S.D., and T.D. Pollard, 1980, J. Cell Biol., 85:414-428). Approximate yield stresses were calculated in the X and Y directions of 0.58 and 1.05 dyn/cm2, respectively. Apparent viscosities measured in the two directions (eta x and eta y) were found to fluctuate with time. The fluctuations in eta x and eta y were shown, statistically, to occur independently of each other. Frequency correlation with dynamoplasmograms indicated that these fluctuations probably occur independently of the streaming cycle. Viscosity was found to be a complex function of shear, indicating that the endoplasm is non-Newtonian. Plots of shear stress vs. rate of shear both parallel and perpendicular to the vein, showed that endoplasm is not a shear thinning material. These experiments have shown that living endoplasm of Physarum is an anisotropic viscoelastic fluid with a yield stress. The endoplasm appears not to be a homogeneous material, but to be composed of heterogeneous domains. PMID:6619187

  11. Watershed Restoration Project

    SciTech Connect

    Julie Thompson; Betsy Macfarlan

    2007-09-27

    In 2003, the U.S. Department of Energy issued the Eastern Nevada Landscape Coalition (ENLC) funding to implement ecological restoration in Gleason Creek and Smith Valley Watersheds. This project was made possible by congressionally directed funding that was provided through the US Department of Energy, Energy Efficiency and Renewable Energy, Office of the Biomass Program. The Ely District Bureau of Land Management (Ely BLM) manages these watersheds and considers them priority areas within the Ely BLM district. These three entities collaborated to address the issues and concerns of Gleason Creek and Smith Valley and prepared a restoration plan to improve the watersheds’ ecological health and resiliency. The restoration process began with watershed-scale vegetation assessments and state and transition models to focus on restoration sites. Design and implementation of restoration treatments ensued and were completed in January 2007. This report describes the restoration process ENLC undertook from planning to implementation of two watersheds in semi-arid Eastern Nevada.

  12. Restoring the worn dentition.

    PubMed

    Ibsen, R L; Ouellet, D F

    1992-01-01

    Strong dental materials and dental porcelains are providing dentists with restorative opportunities that are more conservative because they require less destruction of healthy tooth structure and yield a more esthetic result. In cases of severe wear due to attrition, abrasion, and erosion, this process can be stopped, restoring the esthetics and function by using proper techniques and materials. The case report described in this article demonstrates the conservative restoration of severe wear due to attrition and erosion. Teeth were lengthened, wear was restored, and further wear was ceased by using a combination of bonded porcelain, a heat, light, and self-cure resin system, and a new glass-ionomer restorative material. The result was a strong, durable restoration (that required no anesthesia) with high esthetics.

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

    PubMed Central

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

    2015-01-01

    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. PMID:26225772

  14. Endoplasmic reticulum quality control in cancer: friend or foe

    PubMed Central

    Kim, Hana; Bhattacharya, Asmita; Qi, Ling

    2015-01-01

    Quality control systems in the endoplasmic reticulum (ER) mediated by unfolded protein response (UPR) and endoplasmic reticulum associated degradation (ERAD) ensure cellular function and organismal survival. Recent studies have suggested that ER quality-control systems in cancer cells may serve as a double-edged sword that aids progression as well as prevention of tumor growth in a context-dependent manner. Here we review recent advances in our understanding of the complex relationship between ER proteostasis and cancer pathology, with a focus on the two most conserved ER quality-control mechanisms – the IRE1α-XBP1 pathway of the UPR and SEL1L-HRD1 complex of the ERAD. PMID:25794824

  15. From endoplasmic-reticulum stress to the inflammatory response

    PubMed Central

    Zhang, Kezhong; Kaufman, Randal J.

    2009-01-01

    The endoplasmic reticulum is responsible for much of a cell’s protein synthesis and folding, but it also has an important role in sensing cellular stress. Recently, it has been shown that the endoplasmic reticulum mediates a specific set of intracellular signalling pathways in response to the accumulation of unfolded or misfolded proteins, and these pathways are collectively known as the unfolded-protein response. New observations suggest that the unfolded-protein response can initiate inflammation, and the coupling of these responses in specialized cells and tissues is now thought to be fundamental in the pathogenesis of inflammatory diseases. The knowledge gained from this emerging field will aid in the development of therapies for modulating cellular stress and inflammation. PMID:18650916

  16. Endoplasmic reticulum stress in mouse decidua during early pregnancy.

    PubMed

    Gu, Xiao-Wei; Yan, Jia-Qi; Dou, Hai-Ting; Liu, Jie; Liu, Li; Zhao, Meng-Long; Liang, Xiao-Huan; Yang, Zeng-Ming

    2016-10-15

    Unfolded or misfolded protein accumulation in the endoplasmic reticulum lumen leads to endoplasmic reticulum stress (ER stress). Although it is known that ER stress is crucial for mammalian reproduction, little is known about its physiological significance and underlying mechanism during decidualization. Here we show that Ire-Xbp1 signal transduction pathway of unfolded protein response (UPR) is activated in decidual cells. The process of decidualization is compromised by ER stress inhibitor tauroursodeoxycholic acid sodium (TUDCA) and Ire specific inhibitor STF-083010 both in vivo and in vitro. A high concentration of ER stress inducer tunicamycin (TM) suppresses stromal cells proliferation and decidualization, while a lower concentration is beneficial. We further show that ER stress induces DNA damage and polyploidization in stromal cells. In conclusion, our data suggest that the GRP78/Ire1/Xbp1 signaling pathway of ER stress-UPR is activated and involved in mouse decidualization.

  17. Restoring the smile: Inexpensive biologic restorations

    PubMed Central

    Mittal, Neeti P.

    2014-01-01

    Extensive breakdown of primary teeth to the cervical level and their loss in very young children is not uncommon. Owing to increasing concerns over self-appearance, due considerations to esthetic aspects in addition to restoring function are necessary aspects of rehabilitation of mutilated teeth to help children grow into a psychologically balanced personality. The present article describes rehabilitation of grossly decayed teeth with biologic restorations such as dentine posts, dentine post and core and biologic shell crown. This treatment modality provided a cost-effective esthetic solution. PMID:25097656

  18. Utah Paiute Tribal Restoration.

    ERIC Educational Resources Information Center

    Turner, Allen C.

    The Paiute Indian Tribe of Utah Restoration Act (1980) restored federal recognition of the tribe after a quarter century of ambiguous political status, and resulted in significant improvements of educational status of tribal members and intensification of the political presence of Southern Paiutes. Following the Paiute Indian Termination Act…

  19. Power system restoration issues

    SciTech Connect

    Adibi, M.M. ); Kafka, R.J. )

    1991-04-01

    This article describes some of the problems encountered in the three phases of power system restoration (PSR). The three phases of PSR are: Planning for restart and reintegration of the bulk power supply; Actions during system degradation for saving and retaining critical sources of power; Restoration when the power system has stabilized at some degraded level.

  20. Gill's 'History' restored

    NASA Astrophysics Data System (ADS)

    Hurn, Mark

    2009-06-01

    Note about the restoration of the copy of Sir David Gill's 'A History and Description of the Royal Observatory, Cape of Good Hope' in the Library of the Institute of Astronomy, Cambridge. The book was restored with funds provided by the SHA in thanks for facilities for meetings provided to the Institute.

  1. Retributive and restorative justice.

    PubMed

    Wenzel, Michael; Okimoto, Tyler G; Feather, Norman T; Platow, Michael J

    2008-10-01

    The emergence of restorative justice as an alternative model to Western, court-based criminal justice may have important implications for the psychology of justice. It is proposed that two different notions of justice affect responses to rule-breaking: restorative and retributive justice. Retributive justice essentially refers to the repair of justice through unilateral imposition of punishment, whereas restorative justice means the repair of justice through reaffirming a shared value-consensus in a bilateral process. Among the symbolic implications of transgressions, concerns about status and power are primarily related to retributive justice and concerns about shared values are primarily related to restorative justice. At the core of these processes, however, lies the parties' construal of their identity relation, specifically whether or not respondents perceive to share an identity with the offender. The specific case of intergroup transgressions is discussed, as are implications for future research on restoring a sense of justice after rule-breaking.

  2. Humanin Protects RPE Cells from Endoplasmic Reticulum Stress-Induced Apoptosis by Upregulation of Mitochondrial Glutathione

    PubMed Central

    Matsunaga, Douglas; Sreekumar, Parameswaran G.; Ishikawa, Keijiro; Terasaki, Hiroto; Barron, Ernesto; Cohen, Pinchas

    2016-01-01

    Humanin (HN) is a small mitochondrial-encoded peptide with neuroprotective properties. We have recently shown protection of retinal pigmented epithelium (RPE) cells by HN in oxidative stress; however, the effect of HN on endoplasmic reticulum (ER) stress has not been evaluated in any cell type. Our aim here was to study the effect of HN on ER stress-induced apoptosis in RPE cells with a specific focus on ER-mitochondrial cross-talk. Dose dependent effects of ER stressors (tunicamycin (TM), brefeldin A, and thapsigargin) were studied after 12 hr of treatment in confluent primary human RPE cells with or without 12 hr of HN pretreatment (1–20 μg/mL). All three ER stressors induced RPE cell apoptosis in a dose dependent manner. HN pretreatment significantly decreased the number of apoptotic cells with all three ER stressors in a dose dependent manner. HN pretreatment similarly protected U-251 glioma cells from TM-induced apoptosis in a dose dependent manner. HN pretreatment significantly attenuated activation of caspase 3 and ER stress-specific caspase 4 induced by TM. TM treatment increased mitochondrial superoxide production, and HN co-treatment resulted in a decrease in mitochondrial superoxide compared to TM treatment alone. We further showed that depleted mitochondrial glutathione (GSH) levels induced by TM were restored with HN co-treatment. No significant changes were found for the expression of several antioxidant enzymes between TM and TM plus HN groups except for the expression of glutamylcysteine ligase catalytic subunit (GCLC), the rate limiting enzyme required for GSH biosynthesis, which is upregulated with TM and TM+HN treatment. These results demonstrate that ER stress promotes mitochondrial alterations in RPE that lead to apoptosis. We further show that HN has a protective effect against ER stress-induced apoptosis by restoring mitochondrial GSH. Thus, HN should be further evaluated for its therapeutic potential in disorders linked to ER stress. PMID

  3. HCV Causes Chronic Endoplasmic Reticulum Stress Leading to Adaptation and Interference with the Unfolded Protein Response

    PubMed Central

    Merquiol, Emmanuelle; Uzi, Dotan; Mueller, Tobias; Goldenberg, Daniel; Nahmias, Yaakov; Xavier, Ramnik J.

    2011-01-01

    Background The endoplasmic reticulum (ER) is the cellular site for protein folding. ER stress occurs when protein folding capacity is exceeded. This stress induces a cyto-protective signaling cascades termed the unfolded protein response (UPR) aimed at restoring homeostasis. While acute ER stress is lethal, chronic sub-lethal ER stress causes cells to adapt by attenuation of UPR activation. Hepatitis C virus (HCV), a major human pathogen, was shown to cause ER stress, however it is unclear whether HCV induces chronic ER stress, and if so whether adaptation mechanisms are initiated. We wanted to characterize the kinetics of HCV-induced ER stress during infection and assess adaptation mechanisms and their significance. Methods and Findings The HuH7.5.1 cellular system and HCV-transgenic (HCV-Tg) mice were used to characterize HCV-induced ER stress/UPR pathway activation and adaptation. HCV induced a wave of acute ER stress peaking 2–5 days post-infection, which rapidly subsided thereafter. UPR pathways were activated including IRE1 and EIF2α phosphorylation, ATF6 cleavage and XBP-1 splicing. Downstream target genes including GADD34, ERdj4, p58ipk, ATF3 and ATF4 were upregulated. CHOP, a UPR regulated protein was activated and translocated to the nucleus. Remarkably, UPR activity did not return to baseline but remained elevated for up to 14 days post infection suggesting that chronic ER stress is induced. At this time, cells adapted to ER stress and were less responsive to further drug-induced ER stress. Similar results were obtained in HCV-Tg mice. Suppression of HCV by Interferon-α 2a treatment, restored UPR responsiveness to ER stress tolerant cells. Conclusions Our study shows, for the first time, that HCV induces adaptation to chronic ER stress which was reversed upon viral suppression. These finding represent a novel viral mechanism to manipulate cellular response pathways. PMID:21949742

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

    PubMed

    Ruberti, Cristina; Brandizzi, Federica

    2014-01-01

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

  5. Endoplasmic Reticulum Stress and Autophagy in Homocystinuria Patients with Remethylation Defects

    PubMed Central

    Martínez-Pizarro, Ainhoa; Desviat, Lourdes R.; Ugarte, Magdalena; Pérez, Belén; Richard, Eva

    2016-01-01

    Proper function of endoplasmic reticulum (ER) and mitochondria is crucial for cellular homeostasis, and dysfunction at either site as well as perturbation of mitochondria-associated ER membranes (MAMs) have been linked to neurodegenerative and metabolic diseases. Previously, we have observed an increase in ROS and apoptosis levels in patient-derived fibroblasts with remethylation disorders causing homocystinuria. Here we show increased mRNA and protein levels of Herp, Grp78, IP3R1, pPERK, ATF4, CHOP, asparagine synthase and GADD45 in patient-derived fibroblasts suggesting ER stress and calcium perturbations in homocystinuria. In addition, overexpressed MAM-associated proteins (Grp75, σ-1R and Mfn2) were found in these cells that could result in mitochondrial calcium overload and oxidative stress increase. Our results also show an activation of autophagy process and a substantial degradation of altered mitochondria by mitophagy in patient-derived fibroblasts. Moreover, we have observed that autophagy was partially abolished by antioxidants suggesting that ROS participate in this process that may have a protective role. Our findings argue that alterations in Ca2+ homeostasis and autophagy may contribute to the development of this metabolic disorder and suggest a therapeutic potential in homocystinuria for agents that stabilize calcium homeostasis and/or restore the proper function of ER-mitochondria communications. PMID:26959487

  6. Proline biosynthesis is required for endoplasmic reticulum stress tolerance in Saccharomyces cerevisiae.

    PubMed

    Liang, Xinwen; Dickman, Martin B; Becker, Donald F

    2014-10-01

    The amino acid proline is uniquely involved in cellular processes that underlie stress response in a variety of organisms. Proline is known to minimize protein aggregation, but a detailed study of how proline impacts cell survival during accumulation of misfolded proteins in the endoplasmic reticulum (ER) has not been performed. To address this we examined in Saccharomyces cerevisiae the effect of knocking out the PRO1, PRO2, and PRO3 genes responsible for proline biosynthesis. The null mutants pro1, pro2, and pro3 were shown to have increased sensitivity to ER stress relative to wild-type cells, which could be restored by proline or the corresponding genetic complementation. Of these mutants, pro3 was the most sensitive to tunicamycin and was rescued by anaerobic growth conditions or reduced thiol reagents. The pro3 mutant cells have higher intracellular reactive oxygen species, total glutathione, and a NADP(+)/NADPH ratio than wild-type cells under limiting proline conditions. Depletion of proline biosynthesis also inhibits the unfolded protein response (UPR) indicating proline protection involves the UPR. To more broadly test the role of proline in ER stress, increased proline biosynthesis was shown to partially rescue the ER stress sensitivity of a hog1 null mutant in which the high osmolality pathway is disrupted.

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

    PubMed

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

    2014-05-01

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

  8. Calcium Efflux From the Endoplasmic Reticulum Leads to β-Cell Death

    PubMed Central

    Hara, Takashi; Mahadevan, Jana; Kanekura, Kohsuke; Hara, Mariko; Lu, Simin

    2014-01-01

    It has been established that intracellular calcium homeostasis is critical for survival and function of pancreatic β-cells. However, the role of endoplasmic reticulum (ER) calcium homeostasis in β-cell survival and death is not clear. Here we show that ER calcium depletion plays a critical role in β-cell death. Various pathological conditions associated with β-cell death, including ER stress, oxidative stress, palmitate, and chronic high glucose, decreased ER calcium levels and sarcoendoplasmic reticulum Ca2+-ATPase 2b expression, leading to β-cell death. Ectopic expression of mutant insulin and genetic ablation of WFS1, a causative gene for Wolfram syndrome, also decreased ER calcium levels and induced β-cell death. Hyperactivation of calpain-2, a calcium-dependent proapoptotic protease, was detected in β-cells undergoing ER calcium depletion. Ectopic expression of sarcoendoplasmic reticulum Ca2+-ATPase 2b, as well as pioglitazone and rapamycin treatment, could prevent calcium efflux from the ER and mitigate β-cell death under various stress conditions. Our results reveal a critical role of ER calcium depletion in β-cell death and indicate that identification of pathways and chemical compounds restoring ER calcium levels will lead to novel therapeutic modalities and pharmacological interventions for type 1 and type 2 diabetes and other ER-related diseases including Wolfram syndrome. PMID:24424032

  9. Analysis of the endoplasmic reticular Ca2+ requirement for alpha1-antitrypsin processing and transport competence.

    PubMed Central

    Cooper, G R; Brostrom, C O; Brostrom, M A

    1997-01-01

    Depletion of Ca2+ sequestered within the endoplasmic reticulum (ER) of HepG2 hepatoma cells results in the luminal accumulation of immature alpha1-antitrypsin possessing Man8-9 GlcNAc2 oligosaccharide side chains. This study explores the basis for this arrest and describes consequent alterations in the size and rate of secretion of the complex endoglycosidase H-resistant form of the protein. Inhibition of glucosidase I and II with castanospermine or alpha-1,2-mannosidase with 1-deoxymannojirimycin produced altered ER processing intermediates that were rapidly secreted. Subsequent mobilization of ER Ca2+ stores resulted in the appearance and retention of slightly larger related forms of these intermediates. Retention of glycosylated intermediates was not ascribable to an association with alpha1,2-mannosidase or lectin-like chaperones, the intermediates were not degraded and all evidence of ER retention or size alterations produced by Ca2+ depletion was quickly reversed by Ca2+ restoration. Cells that were Ca2+ depleted for 2 h slowly secreted an abnormal slightly smaller complex oligosaccharide form of alpha1-antitrypsin at approximately the same rate as the non-glycosylated protein generated by treatment with tunicamycin. The hypothesis that Ca2+ affects the folding and ER transport competence of glycosylated forms of alpha1-antitrypsin is discussed. PMID:9271078

  10. Bearing restoration by grinding

    NASA Technical Reports Server (NTRS)

    Hanau, H.; Parker, R. J.; Zaretsky, E. V.; Chen, S. M.; Bull, H. L.

    1976-01-01

    A joint program was undertaken by the NASA Lewis Research Center and the Army Aviation Systems Command to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. No bearing failures occurred related to the restoration by grinding process. The risk and cost of a bearing restoration by grinding programs was analyzed. A microeconomic impact analysis was performed.

  11. Fracture resistance of posterior teeth restored with modern restorative materials

    PubMed Central

    Hamouda, Ibrahim M.; Shehata, Salah H.

    2011-01-01

    We studied the fracture resistance of maxillary premolars restored with recent restorative materials. Fifty maxillary premolars were divided into five groups: Group 1 were unprepared teeth; Group 2 were teeth prepared without restoration; Group 3 were teeth restored with tetric ceram HB; Group 4 were teeth restored with InTen S; and Group 5 were teeth restored with Admira. The samples were tested using a universal testing machine. Peak loads at fracture were recorded. The teeth restored with Admira had the highest fracture resistance followed by those restored with InTen-S and tetric ceram HB. Prepared, unrestored teeth were the weakest group. There was a significant difference between the fracture resistance of intact teeth and the prepared, unrestored teeth. There was also a significant difference among the tested restorative materials. Teeth restored with Admira showed no significant difference when compared with the unprepared teeth. It was concluded that the teeth restored with Admira exhibited the highest fracture resistance. PMID:23554719

  12. Ecosystem restoration: Chapter 4

    USGS Publications Warehouse

    Cullinane Thomas, Catherine M.; Skrabis, K. E.; Gascoigne, William

    2012-01-01

    The Department of the Interior extensively supports―through its mission, policy, programs, and funding― the study, planning, implementation, and monitoring of ecosystem restoration. This commitment is reflected in the Department's FY2011-2016 Strategic Plan.

  13. Restoration of Ailing Wetlands

    PubMed Central

    Schmitz, Oswald J.

    2012-01-01

    It is widely held that humankind's destructive tendencies when exploiting natural resources leads to irreparable harm to the environment. Yet, this thinking runs counter to evidence that many ecological systems damaged by severe natural environmental disturbances (e.g., hurricanes) can restore themselves via processes of natural recovery. The emerging field of restoration ecology is capitalizing on the natural restorative tendencies of ecological systems to build a science of repairing the harm inflicted by humans on natural environment. Evidence for this, for example, comes from a new meta-analysis of 124 studies that synthesizes recovery of impacted wetlands worldwide. While it may take up to two human generations to see full recovery, there is promise, given human will, to restore many damaged wetlands worldwide. PMID:22291573

  14. ESTUARINE HABITAT RESTORATION

    SciTech Connect

    Thom, Ronald M.; Borde, Amy B.

    2015-09-01

    Restoring estuarine habitats generally means repairing damages caused by humans and natural forces. Because of the extensive human occupation, development, and use of coastal areas for centuries, the extensive estuarine habitats have been either destroyed or significantly impaired.

  15. Restoration of ailing wetlands.

    PubMed

    Schmitz, Oswald J

    2012-01-01

    It is widely held that humankind's destructive tendencies when exploiting natural resources leads to irreparable harm to the environment. Yet, this thinking runs counter to evidence that many ecological systems damaged by severe natural environmental disturbances (e.g., hurricanes) can restore themselves via processes of natural recovery. The emerging field of restoration ecology is capitalizing on the natural restorative tendencies of ecological systems to build a science of repairing the harm inflicted by humans on natural environment. Evidence for this, for example, comes from a new meta-analysis of 124 studies that synthesizes recovery of impacted wetlands worldwide. While it may take up to two human generations to see full recovery, there is promise, given human will, to restore many damaged wetlands worldwide.

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

    SciTech Connect

    Pan, Mu-Yun; Shen, Yuh-Chiang; Lu, Chien-Hsing; Yang, Shu-Yi; Ho, Tsing-Fen; Peng, Yu-Ta; Chang, Chia-Che

    2012-12-15

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

  17. One step at a time: endoplasmic reticulum-associated degradation

    PubMed Central

    Vembar, Shruthi S.; Brodsky, Jeffrey L.

    2009-01-01

    Protein folding in the endoplasmic reticulum (ER) is monitored by ER quality control (ERQC) mechanisms. Proteins that pass ERQC criteria traffic to their final destinations through the secretory pathway, whereas non-native and unassembled subunits of multimeric proteins are degraded by the ER-associated degradation (ERAD) pathway. During ERAD, molecular chaperones and associated factors recognize and target substrates for retrotranslocation to the cytoplasm, where they are degraded by the ubiquitin–proteasome machinery. The discovery of diseases that are associated with ERAD substrates highlights the importance of this pathway. Here, we summarize our current understanding of each step during ERAD, with emphasis on the factors that catalyse distinct activities. PMID:19002207

  18. Endoplasmic Reticulum Stress and the Inflammatory Basis of Metabolic Disease

    PubMed Central

    Hotamisligil, Gökhan S.

    2010-01-01

    The endoplasmic reticulum (ER) is the major site in the cell for protein folding and trafficking and is central to many cellular functions. Failure of the ER's adaptive capacity results in activation of the unfolded protein response (UPR), which intersects with many different inflammatory and stress signaling pathways. These pathways are also critical in chronic metabolic diseases such as obesity, insulin resistance, and type 2 diabetes. The ER and related signaling networks are emerging as a potential site for the intersection of inflammation and metabolic disease. PMID:20303879

  19. Restoring primary anterior teeth.

    PubMed

    Waggoner, William F

    2002-01-01

    A variety of esthetic restorative materials are available for restoring primary incisors. Knowledge of the specific strengths, weakness, and properties of each material will enhance the clinician's ability to make the best choice of selection for each individual situation. Intracoronal restorations of primary teeth may utilize resin composites, glass ionomer cements, resin-modified ionomers, or polyacid-modified resins. Each has distinct advantages and disadvantages and the clinical conditions of placement may be a strong determining factor as to which material is utilized. Full coronal restoration of primary incisors may be indicated for a number of reasons. Crowns available for restoration of primary incisors include those that are directly bonded onto the tooth, which generally are a resin material, and those crowns that are luted onto the tooth and are some type of stainless steel crown. However, due to lack of supporting clinical data, none of the crowns can be said to be superior to the others under all circumstances. Though caries in the mandibular region is rare, restorative solutions for mandibular incisors are needed. Neither stainless steel crowns nor celluloid crown forms are made specifically for mandibular incisors. Many options exist to repair carious primary incisors, but there is insufficient controlled, clinical data to suggest that one type of restoration is superior to another. This does not discount the fact that dentists have been using many of these crowns for years with much success. Operator preferences, esthetic demands by parents, the child's behavior, and moisture and hemorrhage control are all variables which affect the decision and ultimate outcome of whatever restorative treatment is chosen.

  20. Restoring primary anterior teeth.

    PubMed

    Waggoner, William F

    2002-01-01

    A variety of esthetic restorative materials are available for restoring primary incisors. Knowledge of the specific strengths, weakness, and properties of each material will enhance the clinician's ability to make the best choice of selection for each individual situation. Intracoronal restorations of primary teeth may utilize resin composites, glass ionomer cements, resin-modified ionomers, or polyacid-modified resins. Each has distinct advantages and disadvantages and the clinical conditions of placement may be a strong determining factor as to which material is utilized. Full coronal restoration of primary incisors may be indicated for a number of reasons. Crowns available for restoration of primary incisors include those that are directly bonded onto the tooth, which generally are a resin material, and those crowns that are luted onto the tooth and are some type of stainless steel crown. However, due to lack of supporting clinical data, none of the crowns can be said to be superior to the others under all circumstances. Though caries in the mandibular region is rare, restorative solutions for mandibular incisors are needed. Neither stainless steel crowns nor celluloid crown forms are made specifically for mandibular incisors. Many options exist to repair carious primary incisors, but there is insufficient controlled, clinical data to suggest that one type of restoration is superior to another. This does not discount the fact that dentists have been using many of these crowns for years with much success. Operator preferences, esthetic demands by parents, the child's behavior, and moisture and hemorrhage control are all variables which affect the decision and ultimate outcome of whatever restorative treatment is chosen. PMID:12412967

  1. The Cdc48 machine in endoplasmic reticulum associated protein degradation.

    PubMed

    Wolf, Dieter H; Stolz, Alexandra

    2012-01-01

    The AAA-type ATPase Cdc48 (named p97/VCP in mammals) is a molecular machine in all eukaryotic cells that transforms ATP hydrolysis into mechanic power to unfold and pull proteins against physical forces, which make up a protein's structure and hold it in place. From the many cellular processes, Cdc48 is involved in, its function in endoplasmic reticulum associated protein degradation (ERAD) is understood best. This quality control process for proteins of the secretory pathway scans protein folding and discovers misfolded proteins in the endoplasmic reticulum (ER), the organelle, destined for folding of these proteins and their further delivery to their site of action. Misfolded lumenal and membrane proteins of the ER are detected by chaperones and lectins and retro-translocated out of the ER for degradation. Here the Cdc48 machinery, recruited to the ER membrane, takes over. After polyubiquitylation of the protein substrate, Cdc48 together with its dimeric co-factor complex Ufd1-Npl4 pulls the misfolded protein out and away from the ER membrane and delivers it to down-stream components for degradation by a cytosolic proteinase machine, the proteasome. The known details of the Cdc48-Ufd1-Npl4 motor complex triggered process are subject of this review article. PMID:21945179

  2. Ricin A chain reaches the endoplasmic reticulum after endocytosis

    SciTech Connect

    Liu Qiong; Zhan Jinbiao . E-mail: jzhan2k@zju.edu.cn; Chen Xinhong; Zheng Shu

    2006-05-12

    Ricin is a potent ribosome inactivating protein and now has been widely used for synthesis of immunotoxins. To target ribosome in the mammalian cytosol, ricin must firstly retrograde transport from the endomembrane system to reach the endoplasmic reticulum (ER) where the ricin A chain (RTA) is recognized by ER components that facilitate its membrane translocation to the cytosol. In the study, the fusion gene of enhanced green fluorescent protein (EGFP)-RTA was expressed with the pET-28a (+) system in Escherichia coli under the control of a T7 promoter. The fusion protein showed a green fluorescence. The recombinant protein can be purified by metal chelated affinity chromatography on a column of NTA. The rabbit anti-GFP antibody can recognize the fusion protein of EGFP-RTA just like the EGFP protein. The cytotoxicity of EGFP-RTA and RTA was evaluated by the MTT assay in HeLa and HEP-G2 cells following fluid-phase endocytosis. The fusion protein had a similar cytotoxicity of RTA. After endocytosis, the subcellular location of the fusion protein can be observed with the laser scanning confocal microscopy and the immuno-gold labeling Electro Microscopy. This study provided important evidence by a visualized way to prove that RTA does reach the endoplasmic reticulum.

  3. Endoplasmic reticulum calcium pumps and cancer cell differentiation.

    PubMed

    Papp, Béla; Brouland, Jean-Philippe; Arbabian, Atousa; Gélébart, Pascal; Kovács, Tünde; Bobe, Régis; Enouf, Jocelyne; Varin-Blank, Nadine; Apáti, Agota

    2012-03-05

    The endoplasmic reticulum (ER) is a major intracellular calcium storage pool and a multifunctional organelle that accomplishes several calcium-dependent functions involved in many homeostatic and signaling mechanisms. Calcium is accumulated in the ER by Sarco/Endoplasmic Reticulum Calcium ATPase (SERCA)-type calcium pumps. SERCA activity can determine ER calcium content available for intra-ER functions and for calcium release into the cytosol, and can shape the spatiotemporal characteristics of calcium signals. SERCA function therefore constitutes an important nodal point in the regulation of cellular calcium homeostasis and signaling, and can exert important effects on cell growth, differentiation and survival. In several cell types such as cells of hematopoietic origin, mammary, gastric and colonic epithelium, SERCA2 and SERCA3-type calcium pumps are simultaneously expressed, and SERCA3 expression levels undergo significant changes during cell differentiation, activation or immortalization. In addition, SERCA3 expression is decreased or lost in several tumor types when compared to the corresponding normal tissue. These observations indicate that ER calcium homeostasis is remodeled during cell differentiation, and may present defects due to decreased SERCA3 expression in tumors. Modulation of the state of differentiation of the ER reflected by SERCA3 expression constitutes an interesting new aspect of cell differentiation and tumor biology.

  4. Mitochondria and endoplasmic reticulum crosstalk in amyotrophic lateral sclerosis.

    PubMed

    Manfredi, Giovanni; Kawamata, Hibiki

    2016-06-01

    Physical and functional interactions between mitochondria and the endoplasmic reticulum (ER) are crucial for cell life. These two organelles are intimately connected and collaborate to essential processes, such as calcium homeostasis and phospholipid biosynthesis. The connections between mitochondria and endoplasmic reticulum occur through structures named mitochondria associated membranes (MAMs), which contain lipid rafts and a large number of proteins, many of which serve multiple functions at different cellular sites. Growing evidence strongly suggests that alterations of ER-mitochondria interactions are involved in neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS), a devastating and rapidly fatal motor neuron disease. Mutations in proteins that participate in ER-mitochondria interactions and MAM functions are increasingly being associated with genetic forms of ALS and other neurodegenerative diseases. This evidence strongly suggests that, rather than considering the two organelles separately, a better understanding of the disease process can derive from studying the alterations in their crosstalk. In this review we discuss normal and pathological ER-mitochondria interactions and the evidence that link them to ALS.

  5. Molecular Characterization of Endoplasmic Reticulum Oxidoreductin 1 from Bombyx mori.

    PubMed

    Seo, Minchul; Ryou, Hee-Joo; Yun, Eun-Young; Goo, Tae-Won

    2015-01-01

    We isolated a complementary DNA (cDNA) clone encoding endoplasmic reticulum oxidoreductin 1 (bERO1, a specific oxidant of protein disulfide isomerase (PDI)) from Bombyx mori. This protein has a putative open reading frame (ORF) of 489 amino acids and a predicted size of 57.4 kDa. Although bERO1 protein shares less than 57% amino acid sequence homology with other reported ERO1s, it contains two conserved redox active motifs, a Cys-X-X-X-X-Cys motif of N-terminal and Cys-X-X-Cys-X-X-Cys motif of C-terminal. Both motifs are typically present in ERO1 protein family members. The bEro1 mRNA expression was highest in posterior silk gland on the sixth day of the 5th instar larvae. Expression of bEro1 mRNA also markedly increased during endoplasmic reticulum (ER) stress induced by stimulation with antimycin, calcium ionophore A23187, dithiothreitol, H₂O₂, monencin, and tunicamycin. In addition, expression levels of bEro1 exactly coincided with that of bPdi. This is the first result suggesting that bERO1 plays an essential role in ER quality control through the combined activities of bERO1 and bPDI as a catalyst of protein folding in the ER and sustaining cellular redox homeostasis. PMID:26556347

  6. [Involvement of endoplasmic reticulum stress in solid organ transplantation].

    PubMed

    Pallet, Nicolas; Bouvier, Nicolas; Beaune, Philippe; Legendre, Christophe; Anglicheau, Dany; Thervet, Eric

    2010-04-01

    Endoplasmic reticulum (ER) stress is a situation caused by the accumulation of unfolded proteins in the endoplasmic reticulum, triggering an evolutionary conserved adaptive response termed the unfolded protein response. When adaptation fails, excessive and prolonged ER stress triggers cell suicide. Important roles for ER-initiated cell death pathways have been recognized for several diseases, including diabetes, hypoxia, ischemia/reperfusion injury, neurodegenerative and heart diseases. The implication of the ER stress is not well recognized in solid organ transplantation, but increasing evidence suggests its implication in mediating allograft injury. The purpose of this review is to summarize the mechanisms of ER stress and to discuss its implication during tissue injury in solid organ transplantation. The possible implications of the ER stress in the modifications of cell functional properties and phenotypic changes are also discussed beyond the scope of adaptation and cell death. Increasing the understanding of the cellular and molecular mechanisms of acute and chronic allograft damages could lead to the development of new biomarkers and to the discovery of new therapeutic strategies to prevent the initiation of graft dysfunction or to promote the tissue regeneration after injury. PMID:20412745

  7. Effect of praseodymium on drug metabolism in rat liver smooth and rough endoplasmic reticulum.

    PubMed

    Arvela, P; von Lehmann, B; Grajewski, O; Oberdisse, E

    1980-07-15

    A small i.v. dose (3 mg/kg) of a light lanthanon, praseodymium, impairs the drug metabolizing capacity of both the smooth and rough fractions of rat liver endoplasmic reticulum. This decrease in the activity of drug metabolizing enzymes and in the amount of cytochromes P-450 and b5 is more pronounced in the rough endoplasmic reticulum fraction.

  8. [Cyclic structural changes in endoplasmic reticulum and Golgi apparatus in the hippocampal neurons of ground squirrels during hibernation].

    PubMed

    Bocharova, L S; Gordon, R Ia; Rogachevskiĭ, V V; Ignat'ev, D A; Khutsian, S S

    2011-01-01

    Repetitive remodeling and renewal of the cytoplasmic structures realizing synthesis of proteins accompanies the cycling of ground squirrels between torpor and arousal states during hibernation season. Earlier we have shown partial loss of ribosomes and nucleolus inactivation in CA3 hippocampal pyramidal neurons in each bout of torpor with rapid and full recovery after warming up. Here we describe reversible structural changes in endoplasmic reticulum (ER) and Golgi complex (G) in these neurons. Transformation of ER from mainly cysternal to tubular form and from mainly granular to smooth type occurs at every entrance in torpor, while the opposite change occurs at arousal. Torpor state is also associated with G fragmentation and loss of its flattened cisternae. Appearance in torpor of the autophagosomal vacuoles containing fragments of membrane structures and ribosomes is a sign of their partial destruction. Granular ER restoration, perhaps through assembly from the multilamellar membrane structures, whorls or bags, begins as early as in the middle of the torpor bout, while G flattened cisternae reappear only at warming. ER and G completely restore their structure 2-3 hours after the provoked arousal. Thus, hibernation represents and example of nerve cell structural adaptation to alterations in functional and metabolic activity through both active destruction and renewal of ribosomes, ER, and G. Perhaps, it is the incomplete ER autophagosomal degradation at torpor provides its rapid renewal at arousal by reassembly from the preserved fragments. PMID:21598689

  9. Cell death and survival through the endoplasmic reticulum-mitochondrial axis.

    PubMed

    Bravo-Sagua, R; Rodriguez, A E; Kuzmicic, J; Gutierrez, T; Lopez-Crisosto, C; Quiroga, C; Díaz-Elizondo, J; Chiong, M; Gillette, T G; Rothermel, B A; Lavandero, S

    2013-02-01

    The endoplasmic reticulum has a central role in biosynthesis of a variety of proteins and lipids. Mitochondria generate ATP, synthesize and process numerous metabolites, and are key regulators of cell death. The architectures of endoplasmic reticulum and mitochondria change continually via the process of membrane fusion, fission, elongation, degradation, and renewal. These structural changes correlate with important changes in organellar function. Both organelles are capable of moving along the cytoskeleton, thus changing their cellular distribution. Numerous studies have demonstrated coordination and communication between mitochondria and endoplasmic reticulum. A focal point for these interactions is a zone of close contact between them known as the mitochondrial-associated endoplasmic reticulum membrane (MAM), which serves as a signaling juncture that facilitates calcium and lipid transfer between organelles. Here we review the emerging data on how communication between endoplasmic reticulum and mitochondria can modulate organelle function and determine cellular fate.

  10. Cell Death and Survival Through the Endoplasmic Reticulum-Mitochondrial Axis

    PubMed Central

    Bravo-Sagua, R.; Rodriguez, A.E.; Kuzmicic, J.; Gutierrez, T.; Lopez-Crisosto, C.; Quiroga, C.; Díaz-Elizondo, J.; Chiong, M.; Gillette, T.G.; Rothermel, B.A.; Lavandero, S.

    2014-01-01

    The endoplasmic reticulum has a central role in biosynthesis of a variety of proteins and lipids. Mitochondria generate ATP, synthesize and process numerous metabolites, and are key regulators of cell death. The architectures of endoplasmic reticulum and mitochondria change continually via the process of membrane fusion, fission, elongation, degradation, and renewal. These structural changes correlate with important changes in organellar function. Both organelles are capable of moving along the cytoskeleton, thus changing their cellular distribution. Numerous studies have demonstrated coordination and communication between mitochondria and endoplasmic reticulum. A focal point for these interactions is a zone of close contact between them known as the mitochondrial–associated endoplasmic reticulum membrane (MAM), which serves as a signaling juncture that facilitates calcium and lipid transfer between organelles. Here we review the emerging data on how communication between endoplasmic reticulum and mitochondria can modulate organelle function and determine cellular fate. PMID:23228132

  11. Cell death and survival through the endoplasmic reticulum-mitochondrial axis.

    PubMed

    Bravo-Sagua, R; Rodriguez, A E; Kuzmicic, J; Gutierrez, T; Lopez-Crisosto, C; Quiroga, C; Díaz-Elizondo, J; Chiong, M; Gillette, T G; Rothermel, B A; Lavandero, S

    2013-02-01

    The endoplasmic reticulum has a central role in biosynthesis of a variety of proteins and lipids. Mitochondria generate ATP, synthesize and process numerous metabolites, and are key regulators of cell death. The architectures of endoplasmic reticulum and mitochondria change continually via the process of membrane fusion, fission, elongation, degradation, and renewal. These structural changes correlate with important changes in organellar function. Both organelles are capable of moving along the cytoskeleton, thus changing their cellular distribution. Numerous studies have demonstrated coordination and communication between mitochondria and endoplasmic reticulum. A focal point for these interactions is a zone of close contact between them known as the mitochondrial-associated endoplasmic reticulum membrane (MAM), which serves as a signaling juncture that facilitates calcium and lipid transfer between organelles. Here we review the emerging data on how communication between endoplasmic reticulum and mitochondria can modulate organelle function and determine cellular fate. PMID:23228132

  12. Pancreatic and duodenal homeobox protein 1 (Pdx-1) maintains endoplasmic reticulum calcium levels through transcriptional regulation of sarco-endoplasmic reticulum calcium ATPase 2b (SERCA2b) in the islet β cell.

    PubMed

    Johnson, Justin S; Kono, Tatsuyoshi; Tong, Xin; Yamamoto, Wataru R; Zarain-Herzberg, Angel; Merrins, Matthew J; Satin, Leslie S; Gilon, Patrick; Evans-Molina, Carmella

    2014-11-21

    Although the pancreatic duodenal homeobox 1 (Pdx-1) transcription factor is known to play an indispensable role in β cell development and secretory function, recent data also implicate Pdx-1 in the maintenance of endoplasmic reticulum (ER) health. The sarco-endoplasmic reticulum Ca(2+) ATPase 2b (SERCA2b) pump maintains a steep Ca(2+) gradient between the cytosol and ER lumen. In models of diabetes, our data demonstrated loss of β cell Pdx-1 that occurs in parallel with altered SERCA2b expression, whereas in silico analysis of the SERCA2b promoter revealed multiple putative Pdx-1 binding sites. We hypothesized that Pdx-1 loss under inflammatory and diabetic conditions leads to decreased SERCA2b levels and activity with concomitant alterations in ER health. To test this, siRNA-mediated knockdown of Pdx-1 was performed in INS-1 cells. The results revealed reduced SERCA2b expression and decreased ER Ca(2+), which was measured using fluorescence lifetime imaging microscopy. Cotransfection of human Pdx-1 with a reporter fused to the human SERCA2 promoter increased luciferase activity 3- to 4-fold relative to an empty vector control, and direct binding of Pdx-1 to the proximal SERCA2 promoter was confirmed by chromatin immunoprecipitation. To determine whether restoration of SERCA2b could rescue ER stress induced by Pdx-1 loss, Pdx1(+/-) mice were fed a high-fat diet. Isolated islets demonstrated an increased spliced-to-total Xbp1 ratio, whereas SERCA2b overexpression reduced the Xbp1 ratio to that of wild-type controls. Together, these results identify SERCA2b as a novel transcriptional target of Pdx-1 and define a role for altered ER Ca(2+) regulation in Pdx-1-deficient states.

  13. Creating esthetic composite restorations.

    PubMed

    Grin, D

    2000-05-01

    The purpose of this article is to describe a fabrication technique to assist dental technicians creating esthetic indirect composite restorations. After the teeth have been prepared and the models completed, the technician can begin the fabrication process. Translucent dentin is selected to reduce opacity and enhance the blend with the remaining dentition. High chroma modifiers can then be placed into the fossa area to replicate dentin seen in natural dentition. Different incisal materials can then be layered into the build-up to regulate the value of the restoration. Special effects such as hypocalcification are placed internally to mimic naturally occurring esthetics. Realistic anatomy is created using a small-tipped instrument directly into the final layer of uncured enamel material. Fissure characterization is placed in the restoration to match existing dentition. Fit and margins are verified on separate dies to minimize discrepancies. Path of insertion and proximal contacts are established on a solid model to minimize chairside adjustments.

  14. Restoring the prairie

    SciTech Connect

    Mlot, C.

    1990-12-01

    The US DOE at the Fermi National Accelerator Laboratory in Batavia, Illinois, prairie restoration is taking place in order to conserve the rich topsoil. This is the largest of many prairie restoration experiments. Big bluestem grass (Andropogon gerardi), blue grama (Bouteloua gracilis), and buffalo grass (Buchloe dactyloides) are the main initial grasses grown. After their growth reaches enough biomass to sustain a fire, other prairie plants such as purple prairie clover and dropseed grass appear. The goal of this is to provide a generous refuge for disappearing native plants and animals, a site for scientific research, and a storehouse of genes adapted to a region that produces much of the worlds food. Plans for restoring the marsh and oak savanna, also native to the Fermilab site are also in the works.

  15. Restoration of Shoulder Function.

    PubMed

    Boe, Chelsea C; Elhassan, Bassem T

    2016-08-01

    Restoration of shoulder function in patients with brachial plexus injury can be challenging. Initial reported efforts were focused on stabilizing the shoulder, improving inferior subluxation and restoring abduction and flexion of the joint. Recent advancements and improved understanding of coordinated shoulder motion and the biomechanical properties of the muscles around the shoulder applicable to tendon transfer have expanded available surgical options to improve shoulder function, specifically external rotation. Despite the advances in reconstructive options, brachial plexus injury remains a serious problem that requires complex surgical solutions, prolonged recovery, and acceptance of functional loss. PMID:27387074

  16. Birbeck granule-like "organized smooth endoplasmic reticulum" resulting from the expression of a cytoplasmic YFP-tagged langerin.

    PubMed

    Lenormand, Cédric; Spiegelhalter, Coralie; Cinquin, Bertrand; Bardin, Sabine; Bausinger, Huguette; Angénieux, Catherine; Eckly, Anita; Proamer, Fabienne; Wall, David; Lich, Ben; Tourne, Sylvie; Hanau, Daniel; Schwab, Yannick; Salamero, Jean; de la Salle, Henri

    2013-01-01

    Langerin is required for the biogenesis of Birbeck granules (BGs), the characteristic organelles of Langerhans cells. We previously used a Langerin-YFP fusion protein having a C-terminal luminal YFP tag to dynamically decipher the molecular and cellular processes which accompany the traffic of Langerin. In order to elucidate the interactions of Langerin with its trafficking effectors and their structural impact on the biogenesis of BGs, we generated a YFP-Langerin chimera with an N-terminal, cytosolic YFP tag. This latter fusion protein induced the formation of YFP-positive large puncta. Live cell imaging coupled to a fluorescence recovery after photobleaching approach showed that this coalescence of proteins in newly formed compartments was static. In contrast, the YFP-positive structures present in the pericentriolar region of cells expressing Langerin-YFP chimera, displayed fluorescent recovery characteristics compatible with active membrane exchanges. Using correlative light-electron microscopy we showed that the coalescent structures represented highly organized stacks of membranes with a pentalaminar architecture typical of BGs. Continuities between these organelles and the rough endoplasmic reticulum allowed us to identify the stacks of membranes as a form of "Organized Smooth Endoplasmic Reticulum" (OSER), with distinct molecular and physiological properties. The involvement of homotypic interactions between cytoplasmic YFP molecules was demonstrated using an A206K variant of YFP, which restored most of the Langerin traffic and BG characteristics observed in Langerhans cells. Mutation of the carbohydrate recognition domain also blocked the formation of OSER. Hence, a "double-lock" mechanism governs the behavior of YFP-Langerin, where asymmetric homodimerization of the YFP tag and homotypic interactions between the lectin domains of Langerin molecules participate in its retention and the subsequent formation of BG-like OSER. These observations confirm that

  17. The Unfolded Protein Response, Degradation from the Endoplasmic Reticulum, and Cancer

    PubMed Central

    Tsai, Yien Che; Weissman, Allan M.

    2010-01-01

    The endoplasmic reticulum (ER) is an essential organelle involved in many cellular functions including protein folding and secretion, lipid biosynthesis, and calcium homeostasis. Proteins destined for the cell surface or for secretion are made in the ER, where they are folded and assembled into multi-subunit complexes. The ER plays a vital role in cellular protein quality control by extracting and degrading proteins that are not correctly folded or assembled into native complexes. This process, known as ER-associated degradation (ERAD), ensures that only properly folded and assembled proteins are transported to their final destinations. Besides its role in protein folding and transport in the secretory pathway, the ER regulates the biosynthesis of cholesterol and other membrane lipids. ERAD is an important means to ensure that levels of the responsible enzymes are appropriately maintained. The ER is also a major organelle for oxygen and nutrient sensing as cells adapt to their microenvironment. Stresses that disrupt ER function lead to accumulation of unfolded proteins in the ER, a condition known as ER stress. Cells adapt to ER stress by activating an integrated signal transduction pathway called the unfolded protein response (UPR). The UPR represents a survival response by the cells to restore ER homeostasis. If ER stress persists, cells activate mechanisms that result in cell death. Chronic ER stress is increasingly being recognized as a factor in many human diseases such as diabetes, neurodegenerative disorders, and cancer. In this review, we discuss the roles of the UPR and ERAD in cancer and suggest directions for future research. PMID:21331300

  18. Ursodeoxycholic acid and 4-phenylbutyrate prevent endoplasmic reticulum stress-induced podocyte apoptosis in diabetic nephropathy.

    PubMed

    Cao, Ai-Li; Wang, Li; Chen, Xia; Wang, Yun-Man; Guo, Heng-Jiang; Chu, Shuang; Liu, Cheng; Zhang, Xue-Mei; Peng, Wen

    2016-06-01

    Endoplasmic reticulum (ER) stress, resulting from the accumulation of misfolded and/or unfolded proteins in ER membranes, is involved in the pathogenesis of diabetic nephropathy (DN). The aim of this study was to investigate the role of ER stress inhibitors ursodeoxycholic acid (UDCA) and 4-phenylbutyrate (4-PBA) in the treatment of DN in db/db mice. Findings have revealed that diabetic db/db mice were more hyperglycemic than their non-diabetic controls, and exhibited a marked increase in body weight, water intake, urine volume, fasting plasma glucose, systolic blood pressure, glucose and insulin tolerance. UDCA (40 mg/kg/day) or 4-PBA (100 mg/kg/day) treatment for 12 weeks resulted in an improvement in these biochemical and physical parameters. Moreover, UDCA or 4-PBA intervention markedly decreased urinary albuminuria and attenuated mesangial expansion in diabetic db/db mice, compared with db/db mice treated with vehicle. These beneficial effects of UDCA or 4-PBA on DN were associated with the inhibition of ER stress, as evidenced by the decreased expression of BiP, phospho-IRE1α, phospho-eIF2α, CHOP, ATF-6 and spliced X-box binding protein-1 in vitro and in vivo. UDCA or 4-PBA prevented hyperglycemia-induced or high glucose (HG)-induced apoptosis in podocytes in vivo and in vitro via the inhibition of caspase-3 and caspase-12 activation. Autophagy deficiency was also seen in glomeruli in diabetic mice and HG-incubated podocytes, exhibiting decreased expression of LC3B and Beclin-1, which could be restored by UDCA or 4-PBA treatment. Taken together, our results have revealed an important role of ER stress in the development of DN, and UDCA or 4-PBA treatment may be a potential novel therapeutic approach for the treatment of DN. PMID:26999661

  19. The Monoterpene Carvacrol Generates Endoplasmic Reticulum Stress in the Pathogenic Fungus Candida albicans

    PubMed Central

    Chaillot, Julien; Tebbji, Faiza; Remmal, Adnane; Boone, Charlie; Brown, Grant W.

    2015-01-01

    The monoterpene carvacrol, the major component of oregano and thyme oils, is known to exert potent antifungal activity against the pathogenic yeast Candida albicans. This monoterpene has been the subject of a considerable number of investigations that uncovered extensive pharmacological properties, including antifungal and antibacterial effects. However, its mechanism of action remains elusive. Here, we used integrative chemogenomic approaches, including genome-scale chemical-genetic and transcriptional profiling, to uncover the mechanism of action of carvacrol associated with its antifungal property. Our results clearly demonstrated that fungal cells require the unfolded protein response (UPR) signaling pathway to resist carvacrol. The mutants most sensitive to carvacrol in our genome-wide competitive fitness assay in the yeast Saccharomyces cerevisiae expressed mutations of the transcription factor Hac1 and the endonuclease Ire1, which is required for Hac1 activation by removing a nonconventional intron from the 3′ region of HAC1 mRNA. Confocal fluorescence live-cell imaging revealed that carvacrol affects the morphology and the integrity of the endoplasmic reticulum (ER). Transcriptional profiling of pathogenic yeast C. albicans cells treated with carvacrol demonstrated a bona fide UPR transcriptional signature. Ire1 activity detected by the splicing of HAC1 mRNA in C. albicans was activated by carvacrol. Furthermore, carvacrol was found to potentiate antifungal activity of the echinocandin antifungal caspofungin and UPR inducers dithiothreitol and tunicamycin against C. albicans. This comprehensive chemogenomic investigation demonstrated that carvacrol exerts its antifungal activity by altering ER integrity, leading to ER stress and the activation of the UPR to restore protein-folding homeostasis. PMID:26014932

  20. Calcium transport in tonoplast and endoplasmic reticulum vesicles isolated from cultured carrot cells. [Daucus carota Danvers

    SciTech Connect

    Bush, D.R.; Sze, H.

    1986-02-01

    Two active calcium (Ca/sup 2 +/) transport systems have been identified and partially characterized in membrane vesicles isolated from cultured carrot cells (Daucus carota Danvers). Both transport systems required MgATP for activity and were enhanced by 10 millimolar oxalate. Ca/sup 2 +/ transport in membrane vesicles derived from isolated vacuoles equilibrated at 1.10 grams per cubic centimeter and comigrated with Cl/sup -/-stimulated, NO/sub 3//sup -/-inhibited ATPase activity on sucrose density gradients. Ca/sup 2 +/ transport in this system was insensitive to vanadate, but was inhibited by nitrate, carbonyl cyanide-m-chlorophenylhydrazone (CCCP), N,N'-dicyclohexylcarbodiimide (DCCD), and 4,4-diisothiocyano-2,2'-stilbene disulfonic acid (DIDS). The K/sub m/ for MgATP and Ca/sup 2 +/ were 0.1 mM and 21 micromolar, respectively. The predominant Ca/sup 2 +/ transport system detectable in microsomal membrane preparations equilibrated at a density of 1.13 grams per cubic centimeter and comigrated with the endoplasmic reticulum (ER) marker, antimycin A-insensitive NADH-dependent cytochrome c reductase. Ca/sup 2 +/ transport activity and the ER marker also shifted in parallel in ER shifting experiments. This transport system was inhibited by vanadate (I/sub 50/ = 12 micromolar) and was insensitive to nitrate, CCCP, DCCD, and DIDS. Transport exhibited cooperative MgATP dependent kinetics. Ca/sup 2 +/ dependent kinetics were complex with an apparent K/sub m/ ranging from 0.7 to 2 micromolar. We conclude that the vacuolar-derived system is a Ca/sup 2 +//H/sup +/ antiport located on the tonoplast and that the microsomal transport system is a Ca,Mg-ATPase enriched on the ER. These two Ca/sup 2 +/ transport systems are proposed to restore and maintain cytoplasmic Ca/sup 2 +/ homeostasis under changing cellular and environmental conditions.

  1. The Monoterpene Carvacrol Generates Endoplasmic Reticulum Stress in the Pathogenic Fungus Candida albicans.

    PubMed

    Chaillot, Julien; Tebbji, Faiza; Remmal, Adnane; Boone, Charlie; Brown, Grant W; Bellaoui, Mohammed; Sellam, Adnane

    2015-08-01

    The monoterpene carvacrol, the major component of oregano and thyme oils, is known to exert potent antifungal activity against the pathogenic yeast Candida albicans. This monoterpene has been the subject of a considerable number of investigations that uncovered extensive pharmacological properties, including antifungal and antibacterial effects. However, its mechanism of action remains elusive. Here, we used integrative chemogenomic approaches, including genome-scale chemical-genetic and transcriptional profiling, to uncover the mechanism of action of carvacrol associated with its antifungal property. Our results clearly demonstrated that fungal cells require the unfolded protein response (UPR) signaling pathway to resist carvacrol. The mutants most sensitive to carvacrol in our genome-wide competitive fitness assay in the yeast Saccharomyces cerevisiae expressed mutations of the transcription factor Hac1 and the endonuclease Ire1, which is required for Hac1 activation by removing a nonconventional intron from the 3' region of HAC1 mRNA. Confocal fluorescence live-cell imaging revealed that carvacrol affects the morphology and the integrity of the endoplasmic reticulum (ER). Transcriptional profiling of pathogenic yeast C. albicans cells treated with carvacrol demonstrated a bona fide UPR transcriptional signature. Ire1 activity detected by the splicing of HAC1 mRNA in C. albicans was activated by carvacrol. Furthermore, carvacrol was found to potentiate antifungal activity of the echinocandin antifungal caspofungin and UPR inducers dithiothreitol and tunicamycin against C. albicans. This comprehensive chemogenomic investigation demonstrated that carvacrol exerts its antifungal activity by altering ER integrity, leading to ER stress and the activation of the UPR to restore protein-folding homeostasis. PMID:26014932

  2. High-Density Lipoprotein Prevents Endoplasmic Reticulum Stress-Induced Downregulation of Liver LOX-1 Expression

    PubMed Central

    Hong, Dan; Li, Ling-Fang; Gao, Hai-Chao; Wang, Xiang; Li, Chuan-Chang; Luo, Ying; Bai, Yong-Ping; Zhang, Guo-Gang

    2015-01-01

    Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a specific cell-surface receptor for oxidized-low-density lipoprotein (ox-LDL). The impact of high-density lipoprotein (HDL) on endoplasmic reticulum (ER) stress-mediated alteration of the LOX-1 level in hepatocytes remains unclear. We aimed to investigate the impact on LOX-1 expression by tunicamycin (TM)-induced ER stress and to determine the effect of HDL on TM-affected LOX-1 expression in hepatic L02 cells. Overexpression or silencing of related cellular genes was conducted in TM-treated cells. mRNA expression was evaluated using real-time polymerase chain reaction (PCR). Protein expression was analyzed by western blot and immunocytochemistry. Lipid uptake was examined by DiI-ox-LDL, followed by flow cytometric analysis. The results showed that TM induced the upregulation of ER chaperone GRP78, downregulation of LOX-1 expression, and lipid uptake. Knock down of IRE1 or XBP-1 effectively restored LOX-1 expression and improved lipid uptake in TM-treated cells. HDL treatment prevented the negative impact on LOX-1 expression and lipid uptake induced by TM. Additionally, 1–10 μg/mL HDL significantly reduced the GRP78, IRE1, and XBP-1 expression levels in TM-treated cells. Our findings reveal that HDL could prevent the TM-induced reduction of LOX-1 expression via inhibiting the IRE1/XBP-1 pathway, suggesting a new mechanism for beneficial roles of HDL in improving lipid metabolism. PMID:25923692

  3. High-Density Lipoprotein Prevents Endoplasmic Reticulum Stress-Induced Downregulation of Liver LOX-1 Expression.

    PubMed

    Hong, Dan; Li, Ling-Fang; Gao, Hai-Chao; Wang, Xiang; Li, Chuan-Chang; Luo, Ying; Bai, Yong-Ping; Zhang, Guo-Gang

    2015-01-01

    Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a specific cell-surface receptor for oxidized-low-density lipoprotein (ox-LDL). The impact of high-density lipoprotein (HDL) on endoplasmic reticulum (ER) stress-mediated alteration of the LOX-1 level in hepatocytes remains unclear. We aimed to investigate the impact on LOX-1 expression by tunicamycin (TM)-induced ER stress and to determine the effect of HDL on TM-affected LOX-1 expression in hepatic L02 cells. Overexpression or silencing of related cellular genes was conducted in TM-treated cells. mRNA expression was evaluated using real-time polymerase chain reaction (PCR). Protein expression was analyzed by western blot and immunocytochemistry. Lipid uptake was examined by DiI-ox-LDL, followed by flow cytometric analysis. The results showed that TM induced the upregulation of ER chaperone GRP78, downregulation of LOX-1 expression, and lipid uptake. Knock down of IRE1 or XBP-1 effectively restored LOX-1 expression and improved lipid uptake in TM-treated cells. HDL treatment prevented the negative impact on LOX-1 expression and lipid uptake induced by TM. Additionally, 1-10 μg/mL HDL significantly reduced the GRP78, IRE1, and XBP-1 expression levels in TM-treated cells. Our findings reveal that HDL could prevent the TM-induced reduction of LOX-1 expression via inhibiting the IRE1/XBP-1 pathway, suggesting a new mechanism for beneficial roles of HDL in improving lipid metabolism. PMID:25923692

  4. Overexpression of BiP in tobacco alleviates endoplasmic reticulum stress.

    PubMed Central

    Leborgne-Castel, N; Jelitto-Van Dooren, E P; Crofts, A J; Denecke, J

    1999-01-01

    To study the role of the lumenal binding protein (BiP) in the transport and secretion of proteins, we have produced plants with altered BiP levels. Transgenic plants overexpressing BiP showed dramatically increased BiP mRNA levels but only a modest increase in BiP protein levels. The presence of degradation products in BiP overproducers suggests a regulatory mechanism that increases protein turnover when BiP is abundant. Antisense inhibition of BiP synthesis was not successful, demonstrating that even a minor reduction in the basal BiP level is deleterious to cell viability. Overexpression of BiP leads to downregulation of the basal transcript levels of endogenous BiP genes and greatly reduces the unfolded protein response. The data confirm that BiP transcription is regulated via a feedback mechanism that involves monitoring of BiP protein levels. To test BiP activity in vivo, we designed a functional assay, using the secretory protein alpha-amylase and a cytosolic enzyme as a control for cell viability. During tunicamycin treatment, an overall reduction of alpha-amylase synthesis was observed when compared with the cytosolic marker. We show that the tunicamycin effect is due to the depletion of BiP in the endoplasmic reticulum because coexpressed BiP alone is able to restore efficient alpha-amylase synthesis. This is a novel assay to monitor BiP activity in promoting secretory protein synthesis in vivo. PMID:10072404

  5. Endoplasmic reticulum stress and unfolded protein response in inflammatory bowel disease.

    PubMed

    Cao, Stewart S

    2015-03-01

    In eukaryotic cells, protein folding and modification in the endoplasmic reticulum (ER) is highly sensitive to disturbances of homeostasis. The accumulation of unfolded and misfolded proteins in the ER lumen, termed ER stress, activates intracellular signaling pathways to resolve the protein-folding defect. This unfolded protein response (UPR) increases the capacity of ER protein folding, reduces global protein synthesis, and activates ER-associated protein degradation. If ER stress is too severe or chronic, or the UPR is compromised and not able to restore ER protein-folding homeostasis, numerous apoptotic signaling pathways are activated. Preclinical and clinical studies in the past decade indicate that ER stress and the UPR have a significant impact on the pathogenesis of inflammatory bowel disease. Paneth and goblet cells, 2 epithelial cell populations in the gut, rely on a robust ER function for protein folding and secretion. Several immune cells are orchestrated by ER stress and the UPR for differentiation, activation, migration, and survival. In addition, a variety of exogenous and endogenous molecules in the intestinal lumen affect ER function, making ER stress and the UPR relevant cellular signals in intestinal homeostasis. Recent studies demonstrated that unresolved ER stress and/or dysregulated UPR may cause inflammatory bowel disease by inducing epithelial cell death, impairing mucosal barrier function, and activating proinflammatory response in the gut. With our increased understanding of ER stress in inflammatory bowel disease pathogenesis, it is now possible to develop novel therapies to improve ER protein-folding homeostasis and target-specific UPR pathways in cells residing in the intestinal mucosa.

  6. Paeonol protects against endoplasmic reticulum stress-induced endothelial dysfunction via AMPK/PPARδ signaling pathway.

    PubMed

    Choy, Ker-Woon; Mustafa, Mohd Rais; Lau, Yeh Siang; Liu, Jian; Murugan, Dharmani; Lau, Chi Wai; Wang, Li; Zhao, Lei; Huang, Yu

    2016-09-15

    Endoplasmic reticulum (ER) stress in endothelial cells often leads to endothelial dysfunction which underlies the pathogenesis of cardiovascular diseases. Paeonol, a major phenolic component extracted from Moutan Cortex, possesses various medicinal benefits which have been used extensively in traditional Chinese medicine. The present study investigated the protective mechanism of paeonol against tunicamycin-induced ER stress in isolated mouse aortas and human umbilical vein endothelial cells (HUVECs). Vascular reactivity in aorta was measured using a wire myograph. The effects of paeonol on protein expression of ER stress markers, reactive oxygen species (ROS) production, nitric oxide (NO) bioavailability and peroxisome proliferator-activated receptor δ (PPARδ) activity in the vascular wall were assessed by Western blot, dihydroethidium fluorescence (DHE) or lucigenin enhanced-chemiluminescence, 4-amino-5-methylamino-2',7'-difluorofluorescein (DAF-FM DA) and dual luciferase reporter assay, respectively. Ex vivo treatment with paeonol (0.1μM) for 16h reversed the impaired endothelium-dependent relaxations in C57BJ/6J and PPARδ wild type (WT) mouse aortas following incubation with tunicamycin (0.5μg/mL). Elevated ER stress markers, oxidative stress and reduction of NO bioavailability induced by tunicamycin in HUVECs, C57BJ/6J and PPARδ WT mouse aortas were reversed by paeonol treatment. These beneficial effects of paeonol were diminished in PPARδ knockout (KO) mouse aortas. Paeonol increased the expression of 5' adenosine monophosphate-activated protein kinase (AMPK) and PPARδ expression and activity while restoring the decreased phosphorylation of eNOS. The present study delineates that paeonol protects against tunicamycin-induced vascular endothelial dysfunction by inhibition of ER stress and oxidative stress, thus elevating NO bioavailability via the AMPK/PPARδ signaling pathway.

  7. The Dichotomy of Endoplasmic Reticulum Stress Response in Liver Ischemia-Reperfusion Injury.

    PubMed

    Zhou, Haomming; Zhu, Jianjun; Yue, Shi; Lu, Ling; Busuttil, Ronald W; Kupiec-Weglinski, Jerzy W; Wang, Xuehao; Zhai, Yuan

    2016-02-01

    Endoplasmic reticulum (ER) stress plays critical roles in the pathogenesis of liver ischemia-reperfusion injury (IRI). As ER stress triggers an adaptive cellular response, the question of what determines its functional outcome in liver IRI remains to be defined. In a murine liver partial warm ischemia model, we studied how transient (30 minutes) or prolonged (90 minutes) liver ischemia regulated local ER stress response and autophagy activities and their relationship with liver IRI. Effects of chemical chaperon 4-phenylbutyrate (4-PBA) or autophagy inhibitor 3-methyladenine (3-MA) were evaluated. Our results showed that although the activating transcription factor 6 branch of ER stress response was induced in livers by both types of ischemia, liver autophagy was activated by transient, but inhibited by prolonged, ischemia. Although 3-MA had no effects on liver IRI after prolonged ischemia, it significantly increased liver IRI after transient ischemia. The 4-PBA treatment protected livers from IRI after prolonged ischemia by restoring autophagy flux, and the adjunctive 3-MA treatment abrogated its liver protective effect. The same 4-PBA treatment, however, increased liver IRI and disrupted autophagy flux after transient ischemia. Although both types of ischemia activated 5' adenosine monophosphate-activated protein kinase and inactivated protein kinase B (Akt), prolonged ischemia also resulted in downregulations of autophagy-related gene 3 and autophagy-related gene 5 in ischemic livers. These results indicate a functional dichotomy of ER stress response in liver IRI via its regulation of autophagy. Transient ischemia activates autophagy to protect livers from IRI, whereas prolonged ischemia inhibits autophagy to promote the development of liver IRI.

  8. Endoplasmic reticulum stress signal impairs erythropoietin production: a role for ATF4.

    PubMed

    Chiang, Chih-Kang; Nangaku, Masaomi; Tanaka, Tetsuhiro; Iwawaki, Takao; Inagi, Reiko

    2013-02-15

    Hypoxia upregulates the hypoxia-inducible factor (HIF) pathway and the endoplasmic reticulum (ER) stress signal, unfolded protein response (UPR). The cross talk of both signals affects the pathogenic alteration by hypoxia. Here we showed that ER stress induced by tunicamycin or thapsigargin suppressed inducible (CoCl(2) or hypoxia) transcription of erythropoietin (EPO), a representative HIF target gene, in HepG2. This suppression was inversely correlated with UPR activation, as estimated by expression of the UPR regulator glucose-regulated protein 78, and restored by an ER stress inhibitor, salubrinal, in association with normalization of the UPR state. Importantly, the decreased EPO expression was also observed in HepG2 overexpressing UPR activating transcription factor (ATF)4. Overexpression of mutated ATF4 that lacks the transcriptional activity did not alter EPO transcriptional regulation. Transcriptional activity of the EPO 3'-enhancer, which is mainly regulated by HIF, was abolished by both ER stressors and ATF4 overexpression, while nuclear HIF accumulation or expression of other HIF target genes was not suppressed by ER stress. Chromatin immunoprecipitation analysis identified a novel ATF4 binding site (TGACCTCT) within the EPO 3'-enhancer region, suggesting a distinct role for ATF4 in UPR-dependent suppression of the enhancer. Induction of ER stress in rat liver and kidney by tunicamycin decreased the hepatic and renal mRNA and plasma level of EPO. Collectively, ER stress selectively impairs the transcriptional activity of EPO but not of other HIF target genes. This effect is mediated by suppression of EPO 3'-enhancer activity via ATF4 without any direct effect on HIF, indicating that UPR contributes to oxygen-sensing regulation of EPO. PMID:23242184

  9. Paeonol protects against endoplasmic reticulum stress-induced endothelial dysfunction via AMPK/PPARδ signaling pathway.

    PubMed

    Choy, Ker-Woon; Mustafa, Mohd Rais; Lau, Yeh Siang; Liu, Jian; Murugan, Dharmani; Lau, Chi Wai; Wang, Li; Zhao, Lei; Huang, Yu

    2016-09-15

    Endoplasmic reticulum (ER) stress in endothelial cells often leads to endothelial dysfunction which underlies the pathogenesis of cardiovascular diseases. Paeonol, a major phenolic component extracted from Moutan Cortex, possesses various medicinal benefits which have been used extensively in traditional Chinese medicine. The present study investigated the protective mechanism of paeonol against tunicamycin-induced ER stress in isolated mouse aortas and human umbilical vein endothelial cells (HUVECs). Vascular reactivity in aorta was measured using a wire myograph. The effects of paeonol on protein expression of ER stress markers, reactive oxygen species (ROS) production, nitric oxide (NO) bioavailability and peroxisome proliferator-activated receptor δ (PPARδ) activity in the vascular wall were assessed by Western blot, dihydroethidium fluorescence (DHE) or lucigenin enhanced-chemiluminescence, 4-amino-5-methylamino-2',7'-difluorofluorescein (DAF-FM DA) and dual luciferase reporter assay, respectively. Ex vivo treatment with paeonol (0.1μM) for 16h reversed the impaired endothelium-dependent relaxations in C57BJ/6J and PPARδ wild type (WT) mouse aortas following incubation with tunicamycin (0.5μg/mL). Elevated ER stress markers, oxidative stress and reduction of NO bioavailability induced by tunicamycin in HUVECs, C57BJ/6J and PPARδ WT mouse aortas were reversed by paeonol treatment. These beneficial effects of paeonol were diminished in PPARδ knockout (KO) mouse aortas. Paeonol increased the expression of 5' adenosine monophosphate-activated protein kinase (AMPK) and PPARδ expression and activity while restoring the decreased phosphorylation of eNOS. The present study delineates that paeonol protects against tunicamycin-induced vascular endothelial dysfunction by inhibition of ER stress and oxidative stress, thus elevating NO bioavailability via the AMPK/PPARδ signaling pathway. PMID:27449753

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

    PubMed

    Pan, Mu-Yun; Shen, Yuh-Chiang; Lu, Chien-Hsing; Yang, Shu-Yi; Ho, Tsing-Fen; Peng, Yu-Ta; Chang, Chia-Che

    2012-12-15

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

  11. Endothelin-1-induced endoplasmic reticulum stress in disease.

    PubMed

    Jain, Arjun

    2013-08-01

    The accumulation of unfolded proteins in the endoplasmic reticulum (ER) represents a cellular stress induced by multiple stimuli and pathologic conditions. Recent evidence implicates endothelin-1 (ET-1) in the induction of placental ER stress in pregnancy disorders. ER stress has previously also been implicated in various other disease states, including neurodegenerative disorders, diabetes, and cardiovascular diseases, as has ET-1 in the pathophysiology of these conditions. However, to date, there has been no investigation of the link between ET-1 and the induction of ER stress in these disease states. Based on recent evidence and mechanistic insight into the role of ET-1 in the induction of placental ER stress, the following review attempts to outline the broader implications of ET-1-induced ER stress, as well as strategies for therapeutic intervention based around ET-1. PMID:23740603

  12. Terasaki Spiral Ramps in the Rough Endoplasmic Reticulum

    NASA Astrophysics Data System (ADS)

    Guven, Jemal; Huber, Greg; Valencia, Dulce María

    2014-10-01

    We present a model describing the morphology as well as the assembly of "Terasaki ramps," the recently discovered helicoidal connections linking adjacent sheets of the rough endoplasmic reticulum (ER). The fundamental unit is a localized symmetric double-ramped "parking garage" formed by two separated gently pitched, approximately helicoidal, ramps of opposite chiralities. This geometry is stabilized by a short-range repulsive interaction between ramps associated with bending energy which opposes the long-range attraction associated with tension. The ramp inner boundaries are themselves stabilized by the condensation of membrane-shaping proteins along their length. A mechanism for parking garage self-assembly is proposed involving the nucleation of dipoles at the center of tubular three-way junctions within the smooth ER. Our predictions are compared with the experimental data.

  13. Terasaki spiral ramps in the rough endoplasmic reticulum.

    PubMed

    Guven, Jemal; Huber, Greg; Valencia, Dulce María

    2014-10-31

    We present a model describing the morphology as well as the assembly of "Terasaki ramps," the recently discovered helicoidal connections linking adjacent sheets of the rough endoplasmic reticulum (ER). The fundamental unit is a localized symmetric double-ramped "parking garage" formed by two separated gently pitched, approximately helicoidal, ramps of opposite chiralities. This geometry is stabilized by a short-range repulsive interaction between ramps associated with bending energy which opposes the long-range attraction associated with tension. The ramp inner boundaries are themselves stabilized by the condensation of membrane-shaping proteins along their length. A mechanism for parking garage self-assembly is proposed involving the nucleation of dipoles at the center of tubular three-way junctions within the smooth ER. Our predictions are compared with the experimental data.

  14. The Gp78 ubiquitin ligase: probing endoplasmic reticulum complexity.

    PubMed

    St Pierre, Pascal; Nabi, Ivan R

    2012-02-01

    The endoplasmic reticulum (ER) has been classically divided, based on electron microscopy analysis, into parallel ribosome-studded rough ER sheets and a tubular smooth ER network. Recent studies have identified molecular constituents of the ER, the reticulons and DP1, that drive ER tubule formation and whose expression determines expression of ER sheets and tubules and thereby rough and smooth ER. However, segregation of the ER into only two domains remains simplistic and multiple functionally distinct ER domains necessarily exist. In this review, we will discuss the sub-organization of the ER in different domains focusing on the localization and role of the gp78 ubiquitin ligase in the mitochondria-associated smooth ER and on the evidence for a quality control ERAD domain.

  15. Interaction of the smooth endoplasmic reticulum and mitochondria.

    PubMed

    Goetz, J G; Nabi, I R

    2006-06-01

    The ER (endoplasmic reticulum) is composed of multiple domains including the nuclear envelope, ribosome-studded rough ER and the SER (smooth ER). The SER can also be functionally segregated into domains that regulate ER-Golgi traffic (transitional ER), ERAD (ER-associated degradation), sterol and lipid biosynthesis and calcium sequestration. The last two, as well as apoptosis, are critically regulated by the close association of the SER with mitochondria. Studies with AMFR (autocrine motility factor receptor) have defined an SER domain whose integrity and mitochondrial association can be modulated by ilimaquinone as well as by free cytosolic calcium levels in the normal physiological range. AMFR is an E3 ubiquitin ligase that targets its ligand directly to the SER via a caveolae/raft-dependent pathway. In the present review, we will address the relationship between the calcium-dependent morphology and mitochondrial association of the SER and its various functional roles in the cell.

  16. Endoplasmic reticulum aminopeptidases in the pathogenesis of ankylosing spondylitis.

    PubMed

    Kenna, Tony J; Robinson, Philip C; Haroon, Nigil

    2015-09-01

    There has been significant progress in our understanding of the pathogenesis of AS. The advent of genome-wide association studies has increased the known loci associated with AS to more than 40. The endoplasmic reticulum resident aminopeptidases (ERAP) 1 and 2 were identified in this manner and are of particular interest. There appears to be a genetic as well as a functional interaction of ERAP1 and 2 with HLA-B27 based on the known functions of these molecules. Recent studies on the structure, immunological effects and the peptide-trimming properties of ERAP 1 and 2 have helped to provide insight into their pathogenic potential in AS. In this review, we explore the role of ERAP 1 and 2 in the pathogenesis of AS.

  17. Endoplasmic Reticulum Stress in Skeletal Muscle Homeostasis and Disease

    PubMed Central

    Rayavarapu, Sree; Coley, William

    2013-01-01

    Our appreciation of the role of endoplasmic reticulum(ER) stress pathways in both skeletal muscle homeostasis and the progression of muscle diseases is gaining momentum. This review provides insight into ER stress mechanisms during physiologic and pathological disturbances in skeletal muscle. The role of ER stress in the response to dietary alterations and acute stressors, including its role in autoimmune and genetic muscle disorders, has been described. Recent studies identifying ER stress markers in diseased skeletal muscle are noted. The emerging evidence for ER–mitochondrial interplay in skeletal muscle and its importance during chronic ER stress in activation of both inflammatory and cell death pathways (autophagy, necrosis, and apoptosis) have been discussed. Thus, understanding the ER stress–related molecular pathways underlying physiologic and pathological phenotypes in healthy and diseased skeletal muscle should lead to novel therapeutic targets for muscle disease. PMID:22410828

  18. Sphingolipid Homeostasis in the Endoplasmic Reticulum and Beyond

    PubMed Central

    Breslow, David K.

    2013-01-01

    Sphingolipids are a diverse group of lipids that have essential cellular roles as structural components of membranes and as potent signaling molecules. In recent years, a detailed picture has emerged of the basic biochemistry of sphingolipids—from their initial synthesis in the endoplasmic reticulum (ER), to their elaboration into complex glycosphingolipids, to their turnover and degradation. However, our understanding of how sphingolipid metabolism is regulated in response to metabolic demand and physiologic cues remains incomplete. Here I discuss new insights into the mechanisms that ensure sphingolipid homeostasis, with an emphasis on the ER as a critical regulatory site in sphingolipid metabolism. In particular, Orm family proteins have recently emerged as key ER-localized mediators of sphingolipid homeostasis. A detailed understanding of how cells sense and control sphingolipid production promises to provide key insights into membrane function in health and disease. PMID:23545423

  19. Stacked endoplasmic reticulum sheets are connected by helicoidal membrane motifs

    PubMed Central

    Terasaki, Mark; Shemesh, Tom; Kasthuri, Narayanan; Klemm, Robin W.; Schalek, Richard; Hayworth, Kenneth J.; Hand, Arthur R.; Yankova, Maya; Huber, Greg; Lichtman, Jeff W.; Rapoport, Tom A.; Kozlov, Michael M.

    2013-01-01

    The endoplasmic reticulum (ER) often forms stacked membrane sheets, an arrangement that is likely required to accommodate a maximum of membrane-bound polysomes for secretory protein synthesis. How sheets are stacked is unknown. Here, we used novel staining and automated ultra-thin sectioning electron microscopy methods to analyze stacked ER sheets in neuronal cells and secretory salivary gland cells of mice. Our results show that stacked ER sheets form a continuous membrane system in which the sheets are connected by twisted membrane surfaces with helical edges of left- or right-handedness. The three-dimensional structure of tightly stacked ER sheets resembles a parking garage, in which the different levels are connected by helicoidal ramps. A theoretical model explains the experimental observations and indicates that the structure corresponds to a minimum of elastic energy of sheet edges and surfaces. The structure allows the dense packing of ER sheets in the restricted space of a cell. PMID:23870120

  20. The endoplasmic reticulum: structure, function and response to cellular signaling.

    PubMed

    Schwarz, Dianne S; Blower, Michael D

    2016-01-01

    The endoplasmic reticulum (ER) is a large, dynamic structure that serves many roles in the cell including calcium storage, protein synthesis and lipid metabolism. The diverse functions of the ER are performed by distinct domains; consisting of tubules, sheets and the nuclear envelope. Several proteins that contribute to the overall architecture and dynamics of the ER have been identified, but many questions remain as to how the ER changes shape in response to cellular cues, cell type, cell cycle state and during development of the organism. Here we discuss what is known about the dynamics of the ER, what questions remain, and how coordinated responses add to the layers of regulation in this dynamic organelle. PMID:26433683

  1. The Gp78 ubiquitin ligase: probing endoplasmic reticulum complexity.

    PubMed

    St Pierre, Pascal; Nabi, Ivan R

    2012-02-01

    The endoplasmic reticulum (ER) has been classically divided, based on electron microscopy analysis, into parallel ribosome-studded rough ER sheets and a tubular smooth ER network. Recent studies have identified molecular constituents of the ER, the reticulons and DP1, that drive ER tubule formation and whose expression determines expression of ER sheets and tubules and thereby rough and smooth ER. However, segregation of the ER into only two domains remains simplistic and multiple functionally distinct ER domains necessarily exist. In this review, we will discuss the sub-organization of the ER in different domains focusing on the localization and role of the gp78 ubiquitin ligase in the mitochondria-associated smooth ER and on the evidence for a quality control ERAD domain. PMID:22045301

  2. Interaction of the smooth endoplasmic reticulum and mitochondria.

    PubMed

    Goetz, J G; Nabi, I R

    2006-06-01

    The ER (endoplasmic reticulum) is composed of multiple domains including the nuclear envelope, ribosome-studded rough ER and the SER (smooth ER). The SER can also be functionally segregated into domains that regulate ER-Golgi traffic (transitional ER), ERAD (ER-associated degradation), sterol and lipid biosynthesis and calcium sequestration. The last two, as well as apoptosis, are critically regulated by the close association of the SER with mitochondria. Studies with AMFR (autocrine motility factor receptor) have defined an SER domain whose integrity and mitochondrial association can be modulated by ilimaquinone as well as by free cytosolic calcium levels in the normal physiological range. AMFR is an E3 ubiquitin ligase that targets its ligand directly to the SER via a caveolae/raft-dependent pathway. In the present review, we will address the relationship between the calcium-dependent morphology and mitochondrial association of the SER and its various functional roles in the cell. PMID:16709164

  3. Pharmacological Modulators of Endoplasmic Reticulum Stress in Metabolic Diseases

    PubMed Central

    Jung, Tae Woo; Choi, Kyung Mook

    2016-01-01

    The endoplasmic reticulum (ER) is the principal organelle responsible for correct protein folding, a step in protein synthesis that is critical for the functional conformation of proteins. ER stress is a primary feature of secretory cells and is involved in the pathogenesis of numerous human diseases, such as certain neurodegenerative and cardiometabolic disorders. The unfolded protein response (UPR) is a defense mechanism to attenuate ER stress and maintain the homeostasis of the organism. Two major degradation systems, including the proteasome and autophagy, are involved in this defense system. If ER stress overwhelms the capacity of the cell’s defense mechanisms, apoptotic death may result. This review is focused on the various pharmacological modulators that can protect cells from damage induced by ER stress. The possible mechanisms for cytoprotection are also discussed. PMID:26840310

  4. The plant endoplasmic reticulum: a cell-wide web.

    PubMed

    Sparkes, Imogen A; Frigerio, Lorenzo; Tolley, Nicholas; Hawes, Chris

    2009-10-15

    The ER (endoplasmic reticulum) in higher plants forms a pleomorphic web of membrane tubules and small cisternae that pervade the cytoplasm, but in particular form a polygonal network at the cortex of the cell which may be anchored to the plasma membrane. The network is associated with the actin cytoskeleton and demonstrates extensive mobility, which is most likely to be dependent on myosin motors. The ER is characterized by a number of domains which may be associated with specific functions such as protein storage, or with direct interaction with other organelles such as the Golgi apparatus, peroxisomes and plastids. In the present review we discuss the nature of the network, the role of shape-forming molecules such as the recently described reticulon family of proteins and the function of some of the major domains within the ER network.

  5. Restoring Fossil Creek

    ERIC Educational Resources Information Center

    Flaccus, Kathleen; Vlieg, Julie; Marks, Jane C.; LeRoy, Carri J.

    2004-01-01

    Fossil Creek had been dammed for the past 90 years, and plans were underway to restore the stream. The creek runs through Central Arizona and flows from the high plateaus to the desert, cutting through the same formations that form the Grand Canyon. This article discusses the Fossil Creek monitoring project. In this project, students and teachers…

  6. Model for Coastal Restoration

    SciTech Connect

    Thom, Ronald M.; Judd, Chaeli

    2007-07-27

    Successful restoration of wetland habitats depends on both our understanding of our system and our ability to characterize it. By developing a conceptual model, looking at different spatial scales and integrating diverse data streams: GIS datasets and NASA products, we were able to develop a dynamic model for site prioritization based on both qualitative and quantitative relationships found in the coastal environment.

  7. 14. EAST ELEVATION, COTTAGE. EXTERIOR NEARLY RESTORED. INTERIOR UNDERGOING RESTORATION. ...

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

    14. EAST ELEVATION, COTTAGE. EXTERIOR NEARLY RESTORED. INTERIOR UNDERGOING RESTORATION. EUCALYPTUS TREE PLANTED BY GERTRUDE KEIL PLANNED FOR REMOVAL. - Gold Ridge Farm, 7777 Bodega Avenue, Sebastopol, Sonoma County, CA

  8. [Influence of implant restoration on traditional restoration idea].

    PubMed

    Liu, H C

    2016-01-01

    Implant restoration affected the traditional restoration idea. Artificial implant restoration has a profound influence on the design of dental restoration. Implant supported prostheses have not only changed the method of oral rehabilitation, but also integrated revolutionary concept with the traditional treatment protocol. By using implants, posterior missing molars can be effectively restored and thus eliminating the disadvantages of traditional removable partial denture for Kennedy classification Ⅰ, Ⅱ partically edentulous dentition. Full edentulous arch can also be restored with implant fixed denture which provide much better oral health related quality of life compared with the traditional complete denture. It is useful to master the theory and skills of artificial implant restoration, and to provide a reference for the restoration of oral physiological function.

  9. Autophagy modulates endoplasmic reticulum stress-induced cell death in podocytes: a protective role.

    PubMed

    Cheng, Yu-Chi; Chang, Jer-Ming; Chen, Chien-An; Chen, Hung-Chun

    2015-04-01

    Endoplasmic reticulum stress occurs in a variety of patho-physiological mechanisms and there has been great interest in managing this pathway for the treatment of clinical diseases. Autophagy is closely interconnected with endoplasmic reticulum stress to counteract the possible injurious effects related with the impairment of protein folding. Studies have shown that glomerular podocytes exhibit high rate of autophagy to maintain as terminally differentiated cells. In this study, podocytes were exposed to tunicamycin and thapsigargin to induce endoplasmic reticulum stress. Thapsigargin/tunicamycin treatment induced a significant increase in endoplasmic reticulum stress and of cell death, represented by higher GADD153 and GRP78 expression and propidium iodide flow cytometry, respectively. However, thapsigargin/tunicamycin stimulation also enhanced autophagy development, demonstrated by monodansylcadaverine assay and LC3 conversion. To evaluate the regulatory effects of autophagy on endoplasmic reticulum stress-induced cell death, rapamycin (Rap) or 3-methyladenine (3-MA) was added to enhance or inhibit autophagosome formation. Endoplasmic reticulum stress-induced cell death was decreased at 6 h, but was not reduced at 24 h after Rap+TG or Rap+TM treatment. In contrast, endoplasmic reticulum stress-induced cell death increased at 6 and 24 h after 3-MA+TG or 3-MA+TM treatment. Our study demonstrated that thapsigargin/tunicamycin treatment induced endoplasmic reticulum stress which resulted in podocytes death. Autophagy, which counteracted the induced endoplasmic reticulum stress, was simultaneously enhanced. The salvational role of autophagy was supported by adding Rap/3-MA to mechanistically regulate the expression of autophagy and autophagosome formation. In summary, autophagy helps the podocytes from cell death and may contribute to sustain the longevity as a highly differentiated cell lineage.

  10. Autophagy modulates endoplasmic reticulum stress-induced cell death in podocytes: A protective role

    PubMed Central

    Cheng, Yu-Chi; Chang, Jer-Ming; Chen, Chien-An

    2015-01-01

    Endoplasmic reticulum stress occurs in a variety of patho-physiological mechanisms and there has been great interest in managing this pathway for the treatment of clinical diseases. Autophagy is closely interconnected with endoplasmic reticulum stress to counteract the possible injurious effects related with the impairment of protein folding. Studies have shown that glomerular podocytes exhibit high rate of autophagy to maintain as terminally differentiated cells. In this study, podocytes were exposed to tunicamycin and thapsigargin to induce endoplasmic reticulum stress. Thapsigargin/tunicamycin treatment induced a significant increase in endoplasmic reticulum stress and of cell death, represented by higher GADD153 and GRP78 expression and propidium iodide flow cytometry, respectively. However, thapsigargin/tunicamycin stimulation also enhanced autophagy development, demonstrated by monodansylcadaverine assay and LC3 conversion. To evaluate the regulatory effects of autophagy on endoplasmic reticulum stress-induced cell death, rapamycin (Rap) or 3-methyladenine (3-MA) was added to enhance or inhibit autophagosome formation. Endoplasmic reticulum stress-induced cell death was decreased at 6 h, but was not reduced at 24 h after Rap+TG or Rap+TM treatment. In contrast, endoplasmic reticulum stress-induced cell death increased at 6 and 24 h after 3-MA+TG or 3-MA+TM treatment. Our study demonstrated that thapsigargin/tunicamycin treatment induced endoplasmic reticulum stress which resulted in podocytes death. Autophagy, which counteracted the induced endoplasmic reticulum stress, was simultaneously enhanced. The salvational role of autophagy was supported by adding Rap/3-MA to mechanistically regulate the expression of autophagy and autophagosome formation. In summary, autophagy helps the podocytes from cell death and may contribute to sustain the longevity as a highly differentiated cell lineage. PMID:25322957

  11. Spectral characteristics of sign-alternating self-oscillatory endoplasm mobility in a myxomycete plasmodium

    NASA Astrophysics Data System (ADS)

    Avsievich, T. I.; Frolov, S. V.; Proskurin, S. G.

    2016-01-01

    The results of a short time Fourier transform of the time dependences of the self-oscillatory endoplasm velocity in an isolated strand of the Physarum polycephalum plasmodium recorded using a sign-sensitive laser Doppler microscope are described. Unlike the mode recording an absolute velocity, a sign-sensitive mode makes it possible to detect the pairs of equidistant harmonic components in the time dependence spectra of endoplasm movement. The resulting frequency and amplitude values are used to construct a model adequately describing the alternating endoplasm mobility.

  12. Ecosystem Restoration Research at GWERD

    EPA Science Inventory

    Ground Water and Ecosystems Restoration Division, Ada, OK Mission: Conduct research and technical assistance to provide the scientific basis to support the development of strategies and technologies to protect and restore ground water, surface water, and ecosystems impacted b...

  13. Comparison of aesthetic posterior restorations.

    PubMed

    Trushkowsky, R D

    1991-09-01

    In the past decade there has been an increased desire by the profession and the public for an aesthetic restoration that will restore a posterior tooth to its original form and function. The currently available aesthetic posterior restoration materials and techniques are porcelain, cast ceramic, direct composite, direct-indirect composite, indirect composite, and CAD-CAM fabrications. The indications and contraindications of these restorative materials and proper diagnosis and case selection are described.

  14. Combined amalgam and composite restorations.

    PubMed

    Abu-Hanna, Amer A; Mjör, Ivar A

    2004-01-01

    All indirect restorative techniques involving cast metals, ceramics or resin-based materials are expensive compared to directly placed restorations. A restorative technique is presented that combines the esthetic properties of directly bonded resin-based composite material and the wide range of indications for dental amalgam in stress-bearing areas.

  15. Volume restoration and facial aesthetics.

    PubMed

    Glasgold, Mark J; Glasgold, Robert A; Lam, Samuel M

    2008-11-01

    This article discusses the rationale for the use of volume restoration to restore natural, youthful contours to an aging face. Topics discussed include the discrepancy that can exist between patients' stated wishes and optimal results and the concepts of framing the eye, creating highlights, and restoring facial shape and volume.

  16. Engineering approaches to ecosystem restoration

    SciTech Connect

    Hayes, D.F.

    1998-07-01

    This proceedings CD ROM contains 127 papers on developing and evaluating engineering approaches to wetlands and river restoration. The latest engineering developments are discussed, providing valuable insights to successful approaches for river restoration, wetlands restoration, watershed management, and constructed wetlands for stormwater and wastewater treatment. Potential solutions to a wide variety of ecosystem concerns in urban, suburban, and coastal environments are presented.

  17. Prairie Restoration for Wisconsin Schools.

    ERIC Educational Resources Information Center

    Murray, Molly Fifield; Greenler, Robin McC.

    This packet is composed of several resources for teachers interested in prairie ecology and restoration. "A Guide to Restoration from Site Analysis to Management" focuses on the Prairie/Oak Savanna communities of Wisconsin and takes teachers through the planning and design process for a restoration project on school grounds including site…

  18. Adaptive wiener image restoration kernel

    DOEpatents

    Yuan, Ding

    2007-06-05

    A method and device for restoration of electro-optical image data using an adaptive Wiener filter begins with constructing imaging system Optical Transfer Function, and the Fourier Transformations of the noise and the image. A spatial representation of the imaged object is restored by spatial convolution of the image using a Wiener restoration kernel.

  19. Relativistic Linear Restoring Force

    ERIC Educational Resources Information Center

    Clark, D.; Franklin, J.; Mann, N.

    2012-01-01

    We consider two different forms for a relativistic version of a linear restoring force. The pair comes from taking Hooke's law to be the force appearing on the right-hand side of the relativistic expressions: d"p"/d"t" or d"p"/d["tau"]. Either formulation recovers Hooke's law in the non-relativistic limit. In addition to these two forces, we…

  20. Restoration of Elbow Flexion.

    PubMed

    Loeffler, Bryan J; Lewis, Daniel R

    2016-08-01

    Active elbow flexion is required to position the hand in space, and loss of this function is debilitating. Nerve transfers or nerve grafts to restore elbow flexion may be options when the target muscle is viable, but in delayed reconstruction when the biceps and brachialis are atrophied or damaged, muscle transfer options should be considered. Muscle transfer options are discussed with attention to the advantages and disadvantages of each transfer option. PMID:27387075

  1. PHASE CONTRAST OBSERVATIONS OF THE ENDOPLASMIC RETICULUM IN LIVING TISSUE CULTURES

    PubMed Central

    Rose, George G.; Pomerat, C. M.

    1960-01-01

    Cells from three human sources (two malignant and one fetal) were observed through phase contrast microscopy to contain unusual cytoplasmic images. These were photographed and are discussed as representing the endoplasmic reticulum in the living cell. PMID:13743266

  2. Toll-like receptor 4-induced endoplasmic reticulum stress contributes to endothelial dysfunction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Impairment of vasodilator action of insulin is associated with endothelial dysfunction and insulin resistance. Endoplasmic reticulum (ER) stress is implicated as one of the mechanisms for pathophysiology of various cardiometabolic syndromes, including insulin resistance and endothelial dysfunction. ...

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

    PubMed

    Jawerbaum, Alicia

    2016-10-01

    In this issue, Yung and colleagues (doi: 10.1007/s00125-016-4040-2 ) report endoplasmic reticulum stress in the placenta of patients with gestational diabetes mellitus. With the use of a trophoblast-like cell line, these authors identify putative mechanisms involved in, and treatments to prevent the induction of endoplasmic reticulum stress. Here, the relevance and possible implications of these findings and areas for further research are discussed. PMID:27379669

  4. Membrane protein insertion into the endoplasmic reticulum--another channel tunnel?

    PubMed

    High, S

    1992-08-01

    The synthesis of biological membranes requires the insertion of proteins into a lipid bilayer. The rough endoplasmic reticulum of eukaryotic cells is a principal site of membrane biogenesis. The insertion of proteins into the membrane of the endoplasmic reticulum is mediated by a resident proteinaceous machinery. Over the last five years several different experimental approaches have provided information about the components of the machinery and how it may function.

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

    PubMed

    Jawerbaum, Alicia

    2016-10-01

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

  6. Determinant for endoplasmic reticulum retention in the luminal domain of the human cytomegalovirus US3 glycoprotein.

    PubMed

    Lee, Sungwook; Park, Boyoun; Ahn, Kwangseog

    2003-02-01

    US3 of human cytomegalovirus is an endoplasmic reticulum resident transmembrane glycoprotein that binds to major histocompatibility complex class I molecules and prevents their departure. The endoplasmic reticulum retention signal of the US3 protein is contained in the luminal domain of the protein. To define the endoplasmic reticulum retention sequence in more detail, we have generated a series of deletion and point mutants of the US3 protein. By analyzing the rate of intracellular transport and immunolocalization of the mutants, we have identified Ser58, Glu63, and Lys64 as crucial for retention, suggesting that the retention signal of the US3 protein has a complex spatial arrangement and does not comprise a contiguous sequence of amino acids. We also show that a modified US3 protein with a mutation in any of these amino acids maintains its ability to bind class I molecules; however, such mutated proteins are no longer retained in the endoplasmic reticulum and are not able to block the cell surface expression of class I molecules. These findings indicate that the properties that allow the US3 glycoprotein to be localized in the endoplasmic reticulum and bind major histocompatibility complex class I molecules are located in different parts of the molecule and that the ability of US3 to block antigen presentation is due solely to its ability to retain class I molecules in the endoplasmic reticulum. PMID:12525649

  7. Role of endoplasmic reticulum stress in drug-induced toxicity.

    PubMed

    Foufelle, Fabienne; Fromenty, Bernard

    2016-02-01

    Drug-induced toxicity is a key issue for public health because some side effects can be severe and life-threatening. These adverse effects can also be a major concern for the pharmaceutical companies since significant toxicity can lead to the interruption of clinical trials, or the withdrawal of the incriminated drugs from the market. Recent studies suggested that endoplasmic reticulum (ER) stress could be an important event involved in drug liability, in addition to other key mechanisms such as mitochondrial dysfunction and oxidative stress. Indeed, drug-induced ER stress could lead to several deleterious effects within cells and tissues including accumulation of lipids, cell death, cytolysis, and inflammation. After recalling important information regarding drug-induced adverse reactions and ER stress in diverse pathophysiological situations, this review summarizes the main data pertaining to drug-induced ER stress and its potential involvement in different adverse effects. Drugs presented in this review are for instance acetaminophen (APAP), arsenic trioxide and other anticancer drugs, diclofenac, and different antiretroviral compounds. We also included data on tunicamycin (an antibiotic not used in human medicine because of its toxicity) and thapsigargin (a toxic compound of the Mediterranean plant Thapsia garganica) since both molecules are commonly used as prototypical toxins to induce ER stress in cellular and animal models. PMID:26977301

  8. Proper symmetric and asymmetric endoplasmic reticulum partitioning requires astral microtubules

    PubMed Central

    Smyth, Jeremy T.; Schoborg, Todd A.; Bergman, Zane J.; Riggs, Blake; Rusan, Nasser M.

    2015-01-01

    Mechanisms that regulate partitioning of the endoplasmic reticulum (ER) during cell division are largely unknown. Previous studies have mostly addressed ER partitioning in cultured cells, which may not recapitulate physiological processes that are critical in developing, intact tissues. We have addressed this by analysing ER partitioning in asymmetrically dividing stem cells, in which precise segregation of cellular components is essential for proper development and tissue architecture. We show that in Drosophila neural stem cells, called neuroblasts, the ER asymmetrically partitioned to centrosomes early in mitosis. This correlated closely with the asymmetric nucleation of astral microtubules (MTs) by centrosomes, suggesting that astral MT association may be required for ER partitioning by centrosomes. Consistent with this, the ER also associated with astral MTs in meiotic Drosophila spermatocytes and during syncytial embryonic divisions. Disruption of centrosomes in each of these cell types led to improper ER partitioning, demonstrating the critical role for centrosomes and associated astral MTs in this process. Importantly, we show that the ER also associated with astral MTs in cultured human cells, suggesting that this centrosome/astral MT-based partitioning mechanism is conserved across animal species. PMID:26289801

  9. Protein Bodies in Leaves Exchange Contents through the Endoplasmic Reticulum.

    PubMed

    Saberianfar, Reza; Sattarzadeh, Amirali; Joensuu, Jussi J; Kohalmi, Susanne E; Menassa, Rima

    2016-01-01

    Protein bodies (PBs) are organelles found in seeds whose main function is the storage of proteins that are used during germination for sustaining growth. PBs can also be induced to form in leaves when foreign proteins are produced at high levels in the endoplasmic reticulum (ER) and when fused to one of three tags: Zera®, elastin-like polypeptides (ELP), or hydrophobin-I (HFBI). In this study, we investigate the differences between ELP, HFBI and Zera PB formation, packing, and communication. Our results confirm the ER origin of all three fusion-tag-induced PBs. We show that secretory pathway proteins can be sequestered into all types of PBs but with different patterns, and that different fusion tags can target a specific protein to different PBs. Zera PBs are mobile and dependent on actomyosin motility similar to ELP and HFBI PBs. We show in vivo trafficking of proteins between PBs using GFP photoconversion. We also show that protein trafficking between ELP or HFBI PBs is faster and proteins travel further when compared to Zera PBs. Our results indicate that fusion-tag-induced PBs do not represent terminally stored cytosolic organelles, but that they form in, and remain part of the ER, and dynamically communicate with each other via the ER. We hypothesize that the previously documented PB mobility along the actin cytoskeleton is associated with ER movement rather than independent streaming of detached organelles. PMID:27242885

  10. Prognosis of oocytes showing aggregation of smooth endoplasmic reticulum.

    PubMed

    Ebner, Thomas; Moser, Marianne; Shebl, Omar; Sommerguber, Michael; Tews, Gernot

    2008-01-01

    Few cytoplasmic dysmorphisms of oocytes have been reported to negatively influence the further fate of the ova. One such anomaly, namely the central aggregation of the smooth endoplasmic reticulum (SER), has recently been associated with suboptimal outcome in a limited number of patients. In order to increase prognostic value, it was decided to prospectively screen all intracytoplasmic sperm injection patients within 1 year for eggs showing aggregations of SER. In addition, all deliveries (obstetric and neonatal data) were analysed. Occurrence of SER cluster was related to duration (P < 0.001) and dosage (P < 0.01) of the stimulation. Fertilization (58.9%) and blastulation rate (44.0%) were lower (P < 0.01) in affected ova compared with unaffected counterparts (77.4 and 87.8%, respectively). Pregnancies in women with affected gametes were accompanied by a higher incidence of obstetric problems (P < 0.01) leading to a non-significant trend towards earlier delivery and significantly reduced birthweight (P < 0.05). It is strongly recommended to avoid transfer of embryos/blastocysts derived from SER cluster-positive gametes. Patients have to be informed that even transfer of sibling oocytes without this anomaly involves a higher risk of detrimental outcome.

  11. Quantitative proteomic survey of endoplasmic reticulum in mouse liver.

    PubMed

    Song, Yanping; Jiang, Ying; Ying, Wantao; Gong, Yan; Yan, Yujuan; Yang, Dong; Ma, Jie; Xue, Xiaofang; Zhong, Fan; Wu, Songfeng; Hao, Yunwei; Sun, Aihua; Li, Tao; Sun, Wei; Wei, Handong; Zhu, Yunping; Qian, Xiaohong; He, Fuchu

    2010-03-01

    To gain a better understanding of the critical function of the endoplasmic reticulum (ER) in liver, we carried out a proteomic survey of mouse liver ER. The ER proteome was profiled with a new three-dimensional, gel-based strategy. From 6152 and 6935 MS spectra, 903 and 1042 proteins were identified with at least two peptides matches at 95% confidence in the rough (r) and smooth (s) ER, respectively. Comparison of the rER and sER proteomes showed that calcium-binding proteins are significantly enriched in the sER suggesting that the ion-binding function of the ER is compartmentalized. Comparison of the rat and mouse ER proteomes showed that 662 proteins were common to both, comprising 53.5% and 49.3% of those proteomes, respectively. We proposed that these proteins were stably expressed proteins that were essential for the maintenance of ER function. GO annotation with a hypergeometric model proved this hypothesis. Unexpectedly, 210 unknown proteins and some proteins previously reported to occur in the cytosol were highly enriched in the ER. This study provides a reference map for the ER proteome of liver. Identification of new ER proteins will enhance our current understanding of the ER and also suggest new functions for this organelle.

  12. Naltrexone attenuates endoplasmic reticulum stress induced hepatic injury in mice.

    PubMed

    Moslehi, A; Nabavizadeh, F; Nabavizadeh, Fatemeh; Dehpour, A R; Dehpou, A R; Tavanga, S M; Hassanzadeh, G; Zekri, A; Nahrevanian, H; Sohanaki, H

    2014-09-01

    Endoplasmic reticulum (ER) stress provides abnormalities in insulin action, inflammatory responses, lipoprotein B100 degradation and hepatic lipogenesis. Excess accumulation of triglyceride in hepatocytes may also lead to disorders such as non-alcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Opioid peptides are involved in triglyceride and cholesterol dysregulation, inflammation and cell death. In this study, we evaluated Naltrexone effects on ER stress induced liver injury. To do so, C57/BL6 mice received saline, DMSO and Naltrexone, as control groups. ER stress was induced by tunicamycin (TM) injection. Naltrexone was given before TM administration. Liver blood flow and biochemical serum analysis were measured. Histopathological evaluations, TNF-α measurement and Real-time RT-PCR were also performed. TM challenge provokes steatosis, cellular ballooning and lobular inflammation which significantly reduced in Naltrexone treated animals. ALT, AST and TNF-α increased in the TM group and improved in the Naltrexone plus TM group. Triglyceride and cholesterol levels decreased in TM treated mice with no increase in Naltrexone treated animals. In the Naltrexone plus TM group, gene expression of Bax/Bcl-2 ratio and caspase3 significantly lowered compared with the TM group. In this study, we found that Naltrexone had a notable alleviating role in ER stress induced steatosis and liver injury.

  13. Improvement of chemotherapeutic drug efficacy by endoplasmic reticulum stress.

    PubMed

    Mihailidou, Chrysovalantou; Chatzistamou, Ioulia; Papavassiliou, Athanasios G; Kiaris, Hippokratis

    2015-04-01

    Tunicamycin (TUN), an inhibitor of protein glycosylation and therefore a potent stimulator of endoplasmic reticulum (ER) stress, has been used to improve anticancer drug efficacy, but the underlying mechanism remains obscure. In this study, we show that acute administration of TUN in mice induces the unfolded protein response and suppresses the levels of P21, a cell cycle regulator with anti-apoptotic activity. The inhibition of P21 after ER stress appears to be C/EBP homologous protein (CHOP)-dependent because in CHOP-deficient mice, TUN not only failed to suppress, but rather induced the expression of P21. Results of promoter-activity reporter assays using human cancer cells and mouse fibroblasts indicated that the regulation of P21 by CHOP operates at the level of transcription and involves direct binding of CHOP transcription factor to the P21 promoter. The results of cell viability and clonogenic assays indicate that ER-stress-related suppression of P21 expression potentiates caspase activation and sensitizes cells to doxorubicin treatment, while administration of TUN to mice increases the therapeutic efficacy of anticancer therapy for HepG2 liver and A549 lung cancers.

  14. Heme oxygenase-1 comes back to endoplasmic reticulum

    SciTech Connect

    Kim, Hong Pyo; Pae, Hyun-Ock; Back, Sung Hun; Chung, Su Wol; Woo, Je Moon; Son, Yong; Chung, Hun-Taeg

    2011-01-07

    Research highlights: {yields} Although multiple compartmentalization of HO-1 has been documented, the functional implication of this enzyme at these subcellular organelles is only partially elucidated. {yields} HO-1 expression at ER is induced by a diverse set of conditions that cause ER stressors. {yields} CO may induce HO-1 expression in human ECs by activating Nrf2 through PERK phosphorylation in a positive-feedback manner. {yields} ER-residing HO-1 and its cytoprotective activity against ER stress is discussed. -- Abstract: Originally identified as a rate-limiting enzyme for heme catabolism, heme oxygenase-1 (HO-1) has expanded its roles in anti-inflammation, anti-apoptosis and anti-proliferation for the last decade. Regulation of protein activity by location is well appreciated. Even though multiple compartmentalization of HO-1 has been documented, the functional implication of this enzyme at these subcellular organelles is only partially elucidated. In this review we discuss the endoplasmic reticulum (ER)-residing HO-1 and its cytoprotective activity against ER stress.

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

    PubMed Central

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

    2014-01-01

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

  16. Paclitaxel inhibits selenoprotein S expression and attenuates endoplasmic reticulum stress.

    PubMed

    Qin, Hong-Shuang; Yu, Pei-Pei; Sun, Ying; Wang, Dan-Feng; Deng, Xiao-Fen; Bao, Yong-Li; Song, Jun; Sun, Lu-Guo; Song, Zhen-Bo; Li, Yu-Xin

    2016-06-01

    The primary effect of the endoplasmic reticulum (ER) stress response or unfolded protein response (UPR) is to reduce the load of unfolded protein and promote survival. However, prolonged and severe ER stress leads to tissue injury and serious diseases. Thus, it is important to identify drugs that can attenuate ER stress for the treatment of diseases. Natural products continue to provide lead compounds for drug discovery and front‑line pharmacotherapy for people worldwide. Previous studies have indicated that selenoprotein S (SelS) is a sensitive and ideal maker of ER stress. In the present study, a firefly luciferase reporter driven by the SelS gene promoter was used to screen for natural compounds capable of attenuating ER stress. From this, paclitaxel (PTX) was identified to efficiently inhibit the promoter activity of the SelS gene, and further results revealed that PTX significantly inhibited the tunicamycin‑induced upregulation of SelS at the mRNA and protein levels in HepG2 and HEK293T cells. In addition, PTX was able to efficiently inhibit the expression of the ER stress marker, glucose‑regulated protein 78, in ER stress, indicating that PTX may reverse ER stress. Taken together, these results suggest that PTX is able to inhibit SelS expression during ER stress and attenuate ER stress. PMID:27109260

  17. Involvement of endoplasmic reticulum stress response in orofacial inflammatory pain.

    PubMed

    Yang, Eun Sun; Bae, Jin Young; Kim, Tae Heon; Kim, Yun Sook; Suk, Kyoungho; Bae, Yong Chul

    2014-12-01

    Endoplasmic reticulum (ER) stress is involved in many neurological diseases and inflammatory responses. Inflammatory mediators induce neuronal damage and trigger the neuropathic or inflammatory pain. But there is very little data on the role of the ER stress response in pain mechanisms. In this study, we explored whether the ER stress response is involved in orofacial inflammatory pain by using a complete Freund's adjuvant (CFA)-injected rat model. The thermal pain hypersensitivity increased significantly after CFA injection. We found that the protein and mRNA levels of ER stress response genes, GRP78/Bip and p-eIF2α, increased significantly in trigeminal ganglion (TG) of CFA-injected rats compared to control animals. In immunofluorescence analysis, a significant increase of GRP78 and p-eIF2α immunopositive neurons was observed in CFA-injected TG compared to control TG. When we administered an ER stress modulator, salubrinal, CFA-induced thermal pain hypersensitivity was temporally reduced. Thus, our study suggests that ER stress responses in TG neurons contribute to CFA-induced inflammatory pain, and may comprise an important molecular mechanism underlying the orofacial inflammatory pain pathway. PMID:25548537

  18. Endoplasmic reticulum stress in adipose tissue augments lipolysis.

    PubMed

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

    2015-01-01

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

  19. The Endoplasmic Reticulum and the Unfolded Protein Response

    PubMed Central

    Malhotra, Jyoti D.; Kaufman, Randal J.

    2009-01-01

    The endoplasmic reticulum (ER) is the site where proteins enter the secretory pathway. Proteins are translocated into the ER lumen in an unfolded state and require protein chaperones and catalysts of protein folding to attain their final appropriate conformation. A sensitive surveillance mechanism exists to prevent misfolded proteins from transiting the secretory pathway and ensures that persistently misfolded proteins are directed towards a degradative pathway. In addition, those processes that prevent accumulation of unfolded proteins in the ER lumen are highly regulated by an intracellular signaling pathway known as the unfolded protein response (UPR). The UPR provides a mechanism by which cells can rapidly adapt to alterations in client protein-folding load in the ER lumen by expanding the capacity for protein folding. In addition, a variety of insults that disrupt protein folding in the ER lumen also activate the UPR. These include changes in intralumenal calcium, altered glycosylation, nutrient deprivation, pathogen infection, expression of folding-defective proteins, and changes in redox status. Persistent protein misfolding initiates apoptotic cascades that are now known to play fundamental roles in the pathogenesis of multiple human diseases including diabetes, atherosclerosis and neurodegenerative diseases. PMID:18023214

  20. Chlamydiae interaction with the endoplasmic reticulum: contact, function and consequences.

    PubMed

    Derré, Isabelle

    2015-07-01

    Chlamydiae and chlamydiae-related organisms are obligate intracellular bacterial pathogens. They reside in a membrane-bound compartment termed the inclusion and have evolved sophisticated mechanisms to interact with cellular organelles. This review focuses on the nature, the function(s) and the consequences of chlamydiae-inclusion interaction with the endoplasmic reticulum (ER). The inclusion membrane establishes very close contact with the ER at specific sites termed ER-inclusion membrane contact sites (MCSs). These MCSs are constituted of a specific set of factors, including the C. trachomatis effector protein IncD and the host cell proteins CERT and VAPA/B. Because CERT and VAPA/B have a demonstrated role in the non-vesicular trafficking of lipids between the ER and the Golgi, it was proposed that Chlamydia establish MCSs with the ER to acquire host lipids. However, the recruitment of additional factors to ER-inclusion MCSs, such as the ER calcium sensor STIM1, may suggest additional functions unrelated to lipid acquisition. Finally, chlamydiae interaction with the ER appears to induce the ER stress response, but this response is quickly dampened by chlamydiae to promote host cell survival. PMID:25930206

  1. Endoplasmic reticulum localization and activity of maize auxin biosynthetic enzymes.

    PubMed

    Kriechbaumer, Verena; Seo, Hyesu; Park, Woong June; Hawes, Chris

    2015-09-01

    Auxin is a major growth hormone in plants and the first plant hormone to be discovered and studied. Active research over >60 years has shed light on many of the molecular mechanisms of its action including transport, perception, signal transduction, and a variety of biosynthetic pathways in various species, tissues, and developmental stages. The complexity and redundancy of the auxin biosynthetic network and enzymes involved raises the question of how such a system, producing such a potent agent as auxin, can be appropriately controlled at all. Here it is shown that maize auxin biosynthesis takes place in microsomal as well as cytosolic cellular fractions from maize seedlings. Most interestingly, a set of enzymes shown to be involved in auxin biosynthesis via their activity and/or mutant phenotypes and catalysing adjacent steps in YUCCA-dependent biosynthesis are localized to the endoplasmic reticulum (ER). Positioning of auxin biosynthetic enzymes at the ER could be necessary to bring auxin biosynthesis in closer proximity to ER-localized factors for transport, conjugation, and signalling, and allow for an additional level of regulation by subcellular compartmentation of auxin action. Furthermore, it might provide a link to ethylene action and be a factor in hormonal cross-talk as all five ethylene receptors are ER localized.

  2. Regulation of endoplasmic reticulum turnover by selective autophagy.

    PubMed

    Khaminets, Aliaksandr; Heinrich, Theresa; Mari, Muriel; Grumati, Paolo; Huebner, Antje K; Akutsu, Masato; Liebmann, Lutz; Stolz, Alexandra; Nietzsche, Sandor; Koch, Nicole; Mauthe, Mario; Katona, Istvan; Qualmann, Britta; Weis, Joachim; Reggiori, Fulvio; Kurth, Ingo; Hübner, Christian A; Dikic, Ivan

    2015-06-18

    The endoplasmic reticulum (ER) is the largest intracellular endomembrane system, enabling protein and lipid synthesis, ion homeostasis, quality control of newly synthesized proteins and organelle communication. Constant ER turnover and modulation is needed to meet different cellular requirements and autophagy has an important role in this process. However, its underlying regulatory mechanisms remain unexplained. Here we show that members of the FAM134 reticulon protein family are ER-resident receptors that bind to autophagy modifiers LC3 and GABARAP, and facilitate ER degradation by autophagy ('ER-phagy'). Downregulation of FAM134B protein in human cells causes an expansion of the ER, while FAM134B overexpression results in ER fragmentation and lysosomal degradation. Mutant FAM134B proteins that cause sensory neuropathy in humans are unable to act as ER-phagy receptors. Consistently, disruption of Fam134b in mice causes expansion of the ER, inhibits ER turnover, sensitizes cells to stress-induced apoptotic cell death and leads to degeneration of sensory neurons. Therefore, selective ER-phagy via FAM134 proteins is indispensable for mammalian cell homeostasis and controls ER morphology and turnover in mice and humans.

  3. LDL–cholesterol transport to the endoplasmic reticulum: current concepts

    PubMed Central

    Pfisterer, Simon G.; Peränen, Johan; Ikonen, Elina

    2016-01-01

    Purpose of review In this article, we summarize the present information related to the export of LDL-derived cholesterol from late endosomes, with a focus on Nieman-Pick disease, type C1 (NPC1) cholesterol delivery toward the endoplasmic reticulum (ER). We review data suggesting that several pathways may operate in parallel, including membrane transport routes and membrane contact sites (MCSs). Recent findings There is increasing appreciation that MCSs provide an important mechanism for intermembrane lipid transfer. In late endosome–ER contacts, three protein bridges involving oxysterol binding protein related protein (ORP)1L-vesicle associated membrane protein-associated protein (VAP), steroidogenic acute regulatory protein (StAR)D3-VAP and ORP5-NPC1 proteins have been reported. How much they contribute to the flux of LDL–cholesterol to the ER is currently open. Studies for lipid transfer via MCSs have been most advanced in Saccharomyces cerevisiae. Recently, a new sterol-binding protein family conserved between yeast and man was identified. Its members localize at MCSs and were named lipid transfer protein anchored at membrane contact sites (Lam) proteins. In yeast, sterol transfer between the ER and the yeast lysosome may be facilitated by a Lam protein. Summary Increasing insights into the role of MCSs in directional sterol delivery between membranes propose that they might provide routes for LDL–cholesterol transfer to the ER. Future work should reveal which specific contacts may operate for this, and how they are controlled by cholesterol homeostatic machineries. PMID:27054443

  4. Endoplasmic Reticulum Stress in Beta Cells and Development of Diabetes

    PubMed Central

    Fonseca, Sonya G.; Burcin, Mark; Gromada, Jesper; Urano, Fumihiko

    2009-01-01

    The endoplasmic reticulum (ER) is a cellular compartment responsible for multiple important cellular functions including the biosynthesis and folding of newly synthesized proteins destined for secretion, such as insulin. A myriad of pathological and physiological factors perturb ER function and cause dysregulation of ER homeostasis, leading to ER stress. ER stress elicits a signaling cascade to mitigate stress, the Unfolded Protein Response (UPR). As long as the UPR can relieve stress, cells can produce the proper amount of proteins and maintain ER homeostasis. If the UPR, however, fails to maintain ER homeostasis, cells will undergo apoptosis. Activation of the UPR is critical to the survival of insulin-producing pancreatic β-cells with high secretory protein production. Any disruption of ER homeostasis in β-cells can lead to cell death and contribute to the pathogenesis of diabetes. There are several models of ER stress-mediated diabetes. In this review, we outline the underlying molecular mechanisms of ER stress-mediated β-cell dysfunction and death during the progression of diabetes. PMID:19665428

  5. Endoplasmic reticulum stress regulation in hematopoietic stem cells.

    PubMed

    Miharada, Kenichi

    2016-08-01

    Adult hematopoietic stem cells (HSCs) reside in bone marrow and are maintained in a dormant state within a special microenvironment, their so-called "niche". Detaching from the niche induces cell cycle progression, resulting in a reduction of the reconstitution capacity of HSCs. In contrast, fetal liver HSCs actively divide without losing their stem cell potentials. Thus, it has been unclear what types of cellular responses and metabolic changes occur in growing HSCs. We previously discovered that HSCs express relatively low levels of endoplasmic reticulum (ER) chaperone proteins governing protein folding, making HSCs vulnerable to an elevation of stress signals caused by accumulation of un-/misfolded proteins (ER stress) upon in vitro culture. Interestingly, fetal liver HSCs do not show ER stress elevation despite unchanged levels of chaperone proteins. Our latest studies utilizing multiple mouse models revealed that in the fetal liver bile acids as chemical chaperones play a key role supporting the protein folding which results in the suppression of ER stress induction. These findings highlight the importance of ER stress regulations in hematopoiesis. PMID:27599423

  6. Protein Bodies in Leaves Exchange Contents through the Endoplasmic Reticulum

    PubMed Central

    Saberianfar, Reza; Sattarzadeh, Amirali; Joensuu, Jussi J.; Kohalmi, Susanne E.; Menassa, Rima

    2016-01-01

    Protein bodies (PBs) are organelles found in seeds whose main function is the storage of proteins that are used during germination for sustaining growth. PBs can also be induced to form in leaves when foreign proteins are produced at high levels in the endoplasmic reticulum (ER) and when fused to one of three tags: Zera®, elastin-like polypeptides (ELP), or hydrophobin-I (HFBI). In this study, we investigate the differences between ELP, HFBI and Zera PB formation, packing, and communication. Our results confirm the ER origin of all three fusion-tag-induced PBs. We show that secretory pathway proteins can be sequestered into all types of PBs but with different patterns, and that different fusion tags can target a specific protein to different PBs. Zera PBs are mobile and dependent on actomyosin motility similar to ELP and HFBI PBs. We show in vivo trafficking of proteins between PBs using GFP photoconversion. We also show that protein trafficking between ELP or HFBI PBs is faster and proteins travel further when compared to Zera PBs. Our results indicate that fusion-tag-induced PBs do not represent terminally stored cytosolic organelles, but that they form in, and remain part of the ER, and dynamically communicate with each other via the ER. We hypothesize that the previously documented PB mobility along the actin cytoskeleton is associated with ER movement rather than independent streaming of detached organelles. PMID:27242885

  7. Calreticulin: non-endoplasmic reticulum functions in physiology and disease

    PubMed Central

    Gold, Leslie I.; Eggleton, Paul; Sweetwyne, Mariya T.; Van Duyn, Lauren B.; Greives, Matthew R.; Naylor, Sara-Megumi; Michalak, Marek; Murphy-Ullrich, Joanne E.

    2010-01-01

    Calreticulin (CRT), when localized to the endoplasmic reticulum (ER), has important functions in directing proper conformation of proteins and glycoproteins, as well as in homeostatic control of cytosolic and ER calcium levels. There is also steadily accumulating evidence for diverse roles for CRT localized outside the ER, including data suggesting important roles for CRT localized to the outer cell surface of a variety of cell types, in the cytosol, and in the extracellular matrix (ECM). Furthermore, the addition of exogenous CRT rescues numerous CRT-driven functions, such as adhesion, migration, phagocytosis, and immunoregulatory functions of CRT-null cells. Recent studies show that topically applied CRT has diverse and profound biological effects that enhance cutaneous wound healing in animal models. This evidence for extracellular bioactivities of CRT has provided new insights into this classically ER-resident protein, despite a lack of knowledge of how CRT exits from the ER to the cell surface or how it is released into the extracellular milieu. Nonetheless, it has become clear that CRT is a multicompartmental protein that regulates a wide array of cellular responses important in physiological and pathological processes, such as wound healing, the immune response, fibrosis, and cancer.—Gold, L. I., Eggleton, P., Sweetwyne, M. T., Van Duyn, L. B., Greives, M. R., Naylor, S.-M., Michalak, M., Murphy-Ullrich, J. E. Calreticulin: non-endoplamic reticulum functions in physiology and disease. PMID:19940256

  8. Proper symmetric and asymmetric endoplasmic reticulum partitioning requires astral microtubules.

    PubMed

    Smyth, Jeremy T; Schoborg, Todd A; Bergman, Zane J; Riggs, Blake; Rusan, Nasser M

    2015-08-01

    Mechanisms that regulate partitioning of the endoplasmic reticulum (ER) during cell division are largely unknown. Previous studies have mostly addressed ER partitioning in cultured cells, which may not recapitulate physiological processes that are critical in developing, intact tissues. We have addressed this by analysing ER partitioning in asymmetrically dividing stem cells, in which precise segregation of cellular components is essential for proper development and tissue architecture. We show that in Drosophila neural stem cells, called neuroblasts, the ER asymmetrically partitioned to centrosomes early in mitosis. This correlated closely with the asymmetric nucleation of astral microtubules (MTs) by centrosomes, suggesting that astral MT association may be required for ER partitioning by centrosomes. Consistent with this, the ER also associated with astral MTs in meiotic Drosophila spermatocytes and during syncytial embryonic divisions. Disruption of centrosomes in each of these cell types led to improper ER partitioning, demonstrating the critical role for centrosomes and associated astral MTs in this process. Importantly, we show that the ER also associated with astral MTs in cultured human cells, suggesting that this centrosome/astral MT-based partitioning mechanism is conserved across animal species. PMID:26289801

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

    PubMed

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

    2014-05-01

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

  10. Terasaki Ramps in the Endoplasmic Reticulum: Structure, Function and Formation

    NASA Astrophysics Data System (ADS)

    Huber, Greg; Guven, Jemal; Valencia, Dulce-Maria

    2015-03-01

    The endoplasmic reticulum (ER) has long been considered an exceedingly important and complex cellular organelle in eukaryotes (like you). It is a membrane structure, part folded lamellae, part tubular network, that both envelopes the nucleus and threads its way outward, all the way to the cell's periphery. Despite the elegant mechanics of bilayer membranes offered by the work of Helfrich and Canham, as far as the ER is concerned, theory has mostly sat on the sidelines. However, refined imaging of the ER has recently revealed beautiful and subtle geometrical forms - simple geometries, from the mathematical point of view - which some have called a ``parking garage for ribosomes.'' I'll review the discovery and physics of Terasaki ramps and discuss their relation to cell-biological questions, such as ER and nuclear-membrane re-organization during mitosis. Rather than being a footnote in a textbook on differential geometry, these structures suggest answers to a number of the ER's structure-function problems.

  11. Low molecular weight Abeta induces collapse of endoplasmic reticulum.

    PubMed

    Lai, Cora Sau-Wan; Preisler, Julie; Baum, Larry; Lee, Daniel Hong-Seng; Ng, Ho-Keung; Hugon, Jacques; So, Kwok-Fai; Chang, Raymond Chuen-Chung

    2009-05-01

    The endoplasmic reticulum (ER) is a dynamic multifunction organelle that is responsible for Ca(2+) homeostasis, protein folding, post-translational modification, protein degradation, and transportation of nascent proteins. Disruption of ER architecture might affect the normal physiology of the cell. In yeast, expansion of the ER is observed under unfolded protein response (UPR) and subsequently induces autophagy initiated from the ER. Here, we found that soluble low molecular weight of Abeta disrupted the anchoring between ER and microtubules (MT) and induced collapse of ER. In addition, it decreased the stability of MT. Subsequently, low molecular weight Abeta triggered autophagy and enhanced lysosomal degradation, as shown by electron microscopy and live-cell imaging. Dysfunction of ER can be further proved in postmortem AD brain and transgenic mice bearing APP Swedish mutation by immunohistochemical analysis of calreticulin. Treatment with Taxol, a MT-stabilizing agent, could partially inhibit collapse of the ER and induction of autophagy. The results show that Abeta-induced disruption of MT can affect the architecture of the ER. Collapse/aggregation of the ER may play an important role in Abeta peptide-triggered neurodegenerative processes.

  12. Involvement of Endoplasmic Reticulum Stress Response in Orofacial Inflammatory Pain

    PubMed Central

    Yang, Eun Sun; Bae, Jin Young; Kim, Tae Heon; Kim, Yun Sook; Suk, Kyoungho

    2014-01-01

    Endoplasmic reticulum (ER) stress is involved in many neurological diseases and inflammatory responses. Inflammatory mediators induce neuronal damage and trigger the neuropathic or inflammatory pain. But there is very little data on the role of the ER stress response in pain mechanisms. In this study, we explored whether the ER stress response is involved in orofacial inflammatory pain by using a complete Freund's adjuvant (CFA)-injected rat model. The thermal pain hypersensitivity increased significantly after CFA injection. We found that the protein and mRNA levels of ER stress response genes, GRP78/Bip and p-eIF2α, increased significantly in trigeminal ganglion (TG) of CFA-injected rats compared to control animals. In immunofluorescence analysis, a significant increase of GRP78 and p-eIF2α immunopositive neurons was observed in CFA-injected TG compared to control TG. When we administered an ER stress modulator, salubrinal, CFA-induced thermal pain hypersensitivity was temporally reduced. Thus, our study suggests that ER stress responses in TG neurons contribute to CFA-induced inflammatory pain, and may comprise an important molecular mechanism underlying the orofacial inflammatory pain pathway. PMID:25548537

  13. Endoplasmic Reticulum Calcium Regulates Epidermal Barrier Response and Desmosomal Structure

    PubMed Central

    Celli, Anna; Crumrine, Debra; Meyer, Jason M.; Mauro, Theodora M.

    2016-01-01

    Ca2+ fluxes direct keratinocyte differentiation, cell-to-cell adhesion, migration, and epidermal barrier homeostasis. We previously showed that intracellular Ca2+ stores constitute a major portion of the calcium gradient especially in the stratum granulosum. Loss of the calcium gradient triggers epidermal barrier homeostatic responses. In this report, using unfixed ex vivo epidermis and human epidermal equivalents we show that endoplasmic reticulum (ER) Ca2+ is released in response to barrier perturbation, and that this release constitutes the major shift in epidermal Ca2+ seen after barrier perturbation. We find that ER Ca2+ release correlates with a transient increase in extracellular Ca2+. Lastly, we show that ER calcium release resulting from barrier perturbation triggers transient desmosomal remodeling, seen as an increase in extracellular space and a loss of the desmosomal intercellular midline. Topical application of thapsigargin, which inhibits the ER Ca2+ ATPase activity without compromising barrier integrity, also leads to desmosomal remodeling and loss of the midline structure. These experiments establish the ER Ca2+ store as a master regulator of the Ca2+ gradient response to epidermal barrier perturbation, and suggest that ER Ca2+ homeostasis also modulates normal desmosomal reorganization, both at rest and after acute barrier perturbation. PMID:27255610

  14. The endoplasmic reticulum: a social network in plant cells.

    PubMed

    Chen, Jun; Doyle, Caitlin; Qi, Xingyun; Zheng, Huanquan

    2012-11-01

    The endoplasmic reticulum (ER) is an interconnected network comprised of ribosome-studded sheets and smooth tubules. The ER plays crucial roles in the biosynthesis and transport of proteins and lipids, and in calcium (Ca(2+) ) regulation in compartmentalized eukaryotic cells including plant cells. To support its well-segregated functions, the shape of the ER undergoes notable changes in response to both developmental cues and outside influences. In this review, we will discuss recent findings on molecular mechanisms underlying the unique morphology and dynamics of the ER, and the importance of the interconnected ER network in cell polarity. In animal and yeast cells, two family proteins, the reticulons and DP1/Yop1, are required for shaping high-curvature ER tubules, while members of the atlastin family of dynamin-like GTPases are involved in the fusion of ER tubules to make an interconnected ER network. In plant cells, recent data also indicate that the reticulons are involved in shaping ER tubules, while RHD3, a plant member of the atlastin GTPases, is required for the generation of an interconnected ER network. We will also summarize the current knowledge on how the ER interacts with other membrane-bound organelles, with a focus on how the ER and Golgi interplay in plant cells. PMID:23046093

  15. The Role of the Endoplasmic Reticulum in Peroxisome Biogenesis

    PubMed Central

    Dimitrov, Lazar; Lam, Sheung Kwan; Schekman, Randy

    2013-01-01

    Peroxisomes are essential cellular organelles involved in lipid metabolism. Patients affected by severe peroxisome biogenesis disorders rarely survive their first year. Genetic screens in several model organisms have identified more than 30 PEX genes that are required for the formation of functional peroxisomes. Despite significant work on the PEX genes, the biogenic origin of peroxisomes remains controversial. For at least two decades, the prevailing model postulated that peroxisomes propagate by growth and fission of preexisting peroxisomes. In this review, we focus on the recent evidence supporting a new, semiautonomous model of peroxisomal biogenesis. According to this model, peroxisomal membrane proteins (PMPs) traffic from the endoplasmic reticulum (ER) to the peroxisome by a vesicular budding, targeting, and fusion process while peroxisomal matrix proteins are imported into the organelle by an autonomous, posttranslational mechanism. We highlight the contradictory conclusions reached to answer the question of how PMPs are inserted into the ER. We then review what we know and what still remains to be elucidated about the mechanism of PMP exit from the ER and the contribution of preperoxisomal vesicles to mature peroxisomes. Finally, we discuss discrepancies in our understanding of de novo peroxisome biogenesis in wild-type cells. We anticipate that resolving these key issues will lead to a more complete picture of peroxisome biogenesis. PMID:23637287

  16. Endoplasmic reticulum localization and activity of maize auxin biosynthetic enzymes.

    PubMed

    Kriechbaumer, Verena; Seo, Hyesu; Park, Woong June; Hawes, Chris

    2015-09-01

    Auxin is a major growth hormone in plants and the first plant hormone to be discovered and studied. Active research over >60 years has shed light on many of the molecular mechanisms of its action including transport, perception, signal transduction, and a variety of biosynthetic pathways in various species, tissues, and developmental stages. The complexity and redundancy of the auxin biosynthetic network and enzymes involved raises the question of how such a system, producing such a potent agent as auxin, can be appropriately controlled at all. Here it is shown that maize auxin biosynthesis takes place in microsomal as well as cytosolic cellular fractions from maize seedlings. Most interestingly, a set of enzymes shown to be involved in auxin biosynthesis via their activity and/or mutant phenotypes and catalysing adjacent steps in YUCCA-dependent biosynthesis are localized to the endoplasmic reticulum (ER). Positioning of auxin biosynthetic enzymes at the ER could be necessary to bring auxin biosynthesis in closer proximity to ER-localized factors for transport, conjugation, and signalling, and allow for an additional level of regulation by subcellular compartmentation of auxin action. Furthermore, it might provide a link to ethylene action and be a factor in hormonal cross-talk as all five ethylene receptors are ER localized. PMID:26139824

  17. Probing Endoplasmic Reticulum Dynamics using Fluorescence Imaging and Photobleaching Techniques

    PubMed Central

    Costantini, Lindsey; Snapp, Erik

    2013-01-01

    This UNIT describes approaches and tools for studying the dynamics and organization of endoplasmic reticulum (ER) membranes and proteins in living cells using commercially available widefield and confocal laser scanning microscopes (CLSM). It has been long appreciated that the ER plays a number of key roles in secretory protein biogenesis, calcium regulation, and lipid synthesis. However, study of these processes has been often restricted to biochemical assays that average the behaviors of millions of lysed cells or to imaging static fixed cells. Now, with new fluorescent protein reporter tools, highly sensitive commercial microscopes, and photobleaching techniques, it is possible to interrogate the behaviors of ER proteins, membranes, and stress pathways in single cells with exquisite spatial and temporal resolution. The ER presents a unique set of imaging challenges including the high mobility of ER membranes, a diverse range of dynamic ER structures, and the influence of post-translational modifications on fluorescent protein reporters. Solutions to these challenges are described and considerations for performing photobleaching assays, especially Fluorescence Recovery after Photobleaching (FRAP) and Fluorescence Loss in Photobleaching (FLIP) for ER proteins will be discussed. In addition, ER reporters and ER-specific pharmacologic compounds are presented with a focus on misfolded secretory protein stress and the Unfolded Protein Response (UPR). PMID:24510787

  18. Percutaneous left ventricular restoration.

    PubMed

    Ige, Mobolaji; Al-Kindi, Sadeer G; Attizzani, Guilherme; Costa, Marco; Oliveira, Guilherme H

    2015-04-01

    The ventricular partitioning device known as Parachute is the first and only percutaneously implantable device aimed at restoration of normal left ventricular geometry in humans. Since its conception, this technology has undergone extensive animal and human testing, with proved feasibility and safety, and is currently being studied in a pivotal randomized clinical trial. This article discusses ventricular remodeling and therapies attempted in the past, details the components of the ventricular partitioning device, describes the implanting technique, and reviews the most current experience of this device in humans.

  19. Percutaneous left ventricular restoration.

    PubMed

    Ige, Mobolaji; Al-Kindi, Sadeer G; Attizzani, Guilherme; Costa, Marco; Oliveira, Guilherme H

    2015-04-01

    The ventricular partitioning device known as Parachute is the first and only percutaneously implantable device aimed at restoration of normal left ventricular geometry in humans. Since its conception, this technology has undergone extensive animal and human testing, with proved feasibility and safety, and is currently being studied in a pivotal randomized clinical trial. This article discusses ventricular remodeling and therapies attempted in the past, details the components of the ventricular partitioning device, describes the implanting technique, and reviews the most current experience of this device in humans. PMID:25834974

  20. Robotic hair restoration.

    PubMed

    Rose, Paul T; Nusbaum, Bernard

    2014-01-01

    The latest innovation to hair restoration surgery has been the introduction of a robotic system for harvesting grafts. This system uses the follicular unit extraction/follicular isolation technique method for harvesting follicular units, which is particularly well suited to the abilities of a robotic technology. The ARTAS system analyzes images of the donor area and then a dual-chamber needle and blunt dissecting punch are used to harvest the follicular units. The robotic technology is now being used in various locations around the world. This article discusses the use of the robotic system, its capabilities, and the advantages and disadvantages of the system. PMID:24267426

  1. Actin-dependent deposition of putative endosomes and endoplasmic reticulum during early stages of wound healing in characean internodal cells.

    PubMed

    Klima, A; Foissner, I

    2011-07-01

    We investigated the behaviour of organelles stained with FM1-43 (putative endosomes) and/or LysoTracker Red (LTred; acidic compartments) and of the endoplasmic reticulum (ER) during healing of puncture and UV-induced wounds in internodal cells of Nitella flexilis and Chara corallina. Immediately after puncture, wounds were passively sealed with a plug of solid vacuolar inclusions, onto which a bipartite wound wall was actively deposited. The outer, callose-containing amorphous layer consisted of remnants of FM1-43- and LTred-labelled organelles, ER cisternae and polysaccharide-containing secretory vesicles, which became deposited in the absence of membrane retrieval (compound exocytosis). During formation of the inner cellulosic layer, exocytosis of secretory vesicles with the newly formed plasma membrane is coupled to endocytosis via coated vesicles. Migration of FM1-43- and LTred-stained organelles, ER and secretory vesicles towards the cell cortex and deposition of a bipartite wound wall could also be induced by spot-like irradiation with ultraviolet light. Cytochalasin D reversibly inhibited the accumulation and deposition of organelles. Our study indicates that active actin-dependent deposition of putative recycling endosomes is required for wound healing (plasma membrane repair) and supports the hypothesis that deposition of ER cisternae helps to restore wounding-disturbed Ca(2+) metabolism.

  2. Chemical chaperon 4-phenylbutyrate protects against the endoplasmic reticulum stress-mediated renal fibrosis in vivo and in vitro.

    PubMed

    Liu, Shing-Hwa; Yang, Ching-Chin; Chan, Ding-Cheng; Wu, Cheng-Tien; Chen, Li-Ping; Huang, Jenq-Wen; Hung, Kuan-Yu; Chiang, Chih-Kang

    2016-04-19

    Renal tubulointerstitial fibrosis is the common and final pathologic change of kidney in end-stage renal disease. Interesting, endoplasmic reticulum (ER) stress is known to contribute to the pathophysiological mechanisms during the development of renal fibrosis. Here, we investigated the effects of chemical chaperon sodium 4-phenylbutyrate (4-PBA) on renal fibrosis in vivo and in vitro. In a rat unilateral ureteral obstruction (UUO) model, 4-PBA mimicked endogenous ER chaperon in the kidneys and significantly reduced glucose regulated protein 78 (GRP78), CCAAT/enhancer binding protein (C/EBP) homologous protein (CHOP), activating transcription factor 4 (ATF4), and phosphorylated JNK protein expressions as well as restored spliced X-box-binding protein 1 (XBP1) expressions in the kidneys of UUO rats. 4-PBA also attenuated the increases of α-smooth muscle actin (α-SMA), connective tissue growth factor (CTGF) protein expressions, tubulointerstitial fibrosis, and apoptosis in the kidneys of UUO rats. Moreover, transforming growth factor (TGF)-β markedly increased ER stress-associated molecules, profibrotic factors, and apoptotic markers in the renal tubular cells (NRK-52E), all of which could be significantly counteracted by 4-PBA treatment. 4-PBA also diminished TGF-β-increased CTGF promoter activity and CTGF mRNA expression in NRK-52E cells. Taken together, our results indicated that 4-PBA acts as an ER chaperone to ameliorate ER stress-induced renal tubular cell apoptosis and renal fibrosis.

  3. Isolation and functional characterization of Sporothrix schenckii ROT2, the encoding gene for the endoplasmic reticulum glucosidase II.

    PubMed

    Robledo-Ortiz, Claudia I; Flores-Carreón, Arturo; Hernández-Cervantes, Arturo; Álvarez-Vargas, Aurelio; Lee, Keunsook K; Díaz-Jiménez, Diana F; Munro, Carol A; Cano-Canchola, Carmen; Mora-Montes, Héctor M

    2012-08-01

    The N-linked glycosylation is a ubiquitous protein modification in eukaryotic cells. During the N-linked glycan synthesis, the precursor Glc(3)Man(9)GlcNAc(2) is processed by endoplasmic reticulum (ER) glucosidases I, II and α1,2-mannosidase, before transporting to the Golgi complex for further structure modifications. In fungi of medical relevance, as Candida albicans and Aspergillus, it is well known that ER glycosidases are important for cell fitness, cell wall organization, virulence, and interaction with the immune system. Despite this, little is known about these enzymes in Sporothrix schenckii, the causative agent of human sporotrichosis. This limited knowledge is due in part to the lack of a genome sequence of this organism. In this work we used degenerate primers and inverse PCR approaches to isolate the open reading frame of S. schenckii ROT2, the encoding gene for α subunit of ER glucosidase II. This S. schenckii gene complemented a Saccharomyces cerevisiae rot2Δ mutant; however, when expressed in a C. albicans rot2Δ mutant, S. schenckii Rot2 partially increased the levels of α-glucosidase activity, but failed to restore the N-linked glycosylation defect associated to the mutation. To our knowledge, this is the first report where a gene involved in protein N-linked glycosylation is isolated from S. schenckii.

  4. Chemical chaperon 4-phenylbutyrate protects against the endoplasmic reticulum stress-mediated renal fibrosis in vivo and in vitro.

    PubMed

    Liu, Shing-Hwa; Yang, Ching-Chin; Chan, Ding-Cheng; Wu, Cheng-Tien; Chen, Li-Ping; Huang, Jenq-Wen; Hung, Kuan-Yu; Chiang, Chih-Kang

    2016-04-19

    Renal tubulointerstitial fibrosis is the common and final pathologic change of kidney in end-stage renal disease. Interesting, endoplasmic reticulum (ER) stress is known to contribute to the pathophysiological mechanisms during the development of renal fibrosis. Here, we investigated the effects of chemical chaperon sodium 4-phenylbutyrate (4-PBA) on renal fibrosis in vivo and in vitro. In a rat unilateral ureteral obstruction (UUO) model, 4-PBA mimicked endogenous ER chaperon in the kidneys and significantly reduced glucose regulated protein 78 (GRP78), CCAAT/enhancer binding protein (C/EBP) homologous protein (CHOP), activating transcription factor 4 (ATF4), and phosphorylated JNK protein expressions as well as restored spliced X-box-binding protein 1 (XBP1) expressions in the kidneys of UUO rats. 4-PBA also attenuated the increases of α-smooth muscle actin (α-SMA), connective tissue growth factor (CTGF) protein expressions, tubulointerstitial fibrosis, and apoptosis in the kidneys of UUO rats. Moreover, transforming growth factor (TGF)-β markedly increased ER stress-associated molecules, profibrotic factors, and apoptotic markers in the renal tubular cells (NRK-52E), all of which could be significantly counteracted by 4-PBA treatment. 4-PBA also diminished TGF-β-increased CTGF promoter activity and CTGF mRNA expression in NRK-52E cells. Taken together, our results indicated that 4-PBA acts as an ER chaperone to ameliorate ER stress-induced renal tubular cell apoptosis and renal fibrosis. PMID:26959118

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

    PubMed

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

    2013-11-01

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

  6. Serine palmitoyltransferase subunit 1 is present in the endoplasmic reticulum, nucleus and focal adhesions, and functions in cell morphology.

    PubMed

    Wei, Jia; Yerokun, Tokunbo; Leipelt, Martina; Haynes, Chris A; Radhakrishna, Harish; Momin, Amin; Kelly, Samuel; Park, Hyejung; Wang, Elaine; Carton, Jill M; Uhlinger, David J; Merrill, Alfred H

    2009-08-01

    Serine palmitoyltransferase (SPT) has been localized to the endoplasmic reticulum (ER) by subcellular fractionation and enzymatic assays, and fluorescence microscopy of epitope-tagged SPT; however, our studies have suggested that SPT subunit 1 might be present also in focal adhesions and the nucleus. These additional locations have been confirmed by confocal microscopy using HEK293 and HeLa cells, and for focal adhesions by the demonstration that SPT1 co-immunoprecipitates with vinculin, a focal adhesion marker protein. The focal adhesion localization of SPT1 is associated with cell morphology, and possibly cell migration, because it is seen in most cells before they reach confluence but disappears when they become confluent, and is restored by a standard scratch-wound healing assay. Conversely, elimination of SPT1 using SPTLC1 siRNA causes cell rounding. Thus, in addition to its "traditional" localization in the ER for de novo sphingolipid biosynthesis, SPT1 is present in other cellular compartments, including focal adhesions where it is associated with cell morphology. PMID:19362163

  7. Intracellular potassium stabilizes human ether-à-go-go-related gene channels for export from endoplasmic reticulum.

    PubMed

    Wang, Lu; Dennis, Adrienne T; Trieu, Phan; Charron, Francois; Ethier, Natalie; Hebert, Terence E; Wan, Xiaoping; Ficker, Eckhard

    2009-04-01

    Several therapeutic compounds have been identified that prolong the QT interval on the electrocardiogram and cause torsade de pointes arrhythmias not by direct block of the cardiac potassium channel human ether-à-go-go-related gene (hERG) but via disruption of hERG trafficking to the cell surface membrane. One example of a clinically important compound class that potently inhibits hERG trafficking are cardiac glycosides. We have shown previously that inhibition of hERG trafficking by cardiac glycosides is initiated via direct block of Na(+)/K(+) pumps and not via off-target interactions with hERG or any other protein. However, it was not known how pump inhibition at the cell surface is coupled to hERG processing in the endoplasmic reticulum. Here, we show that depletion of intracellular K(+)-either indirectly after long-term exposure to cardiac glycosides or directly after exposure to gramicidin in low sodium media-is sufficient to disrupt hERG trafficking. In K(+)-depleted cells, hERG trafficking can be restored by permeating K(+) or Rb(+) ions, incubation at low temperature, exposure to the pharmacological chaperone astemizole, or specific mutations in the selectivity filter of hERG. Our data suggest a novel mechanism for drug-induced trafficking inhibition in which cardiac glycosides produce a [K(+)](i)-mediated conformational defect directly in the hERG channel protein. PMID:19139152

  8. Host endoplasmic reticulum COPII proteins control cell-to-cell spread of the bacterial pathogen Listeria monocytogenes

    PubMed Central

    Gianfelice, Antonella; Le, Phuong H.B.; Rigano, Luciano A.; Saila, Susan; Dowd, Georgina C.; McDivitt, Tina; Bhattacharya, Nilakshee; Hong, Wanjin; Stagg, Scott M.; Ireton, Keith

    2015-01-01

    SUMMARY Listeria monocytogenes is a food-borne pathogen that uses actin–dependent motility to spread between human cells. Cell-to-cell spread involves the formation by motile bacteria of plasma membrane-derived structures termed ‘protrusions’. In cultured enterocytes, the secreted Listeria protein InlC promotes protrusion formation by binding and inhibiting the human scaffolding protein Tuba. Here we demonstrate that protrusions are controlled by human COPII components that direct trafficking from the endoplasmic reticulum. Co-precipitation experiments indicated that the COPII proteins Sec31A and Sec13 interact directly with a Src Homology 3 domain in Tuba. This interaction was antagonized by InlC. Depletion of Sec31A or Sec13 restored normal protrusion formation to a Listeria mutant lacking inlC, without affecting spread of wild-type bacteria. Genetic impairment of the COPII component Sar1 or treatment of cells with brefeldin A affected protrusions similarly to Sec31A or Sec13 depletion. These findings indicated that InlC relieves a host-mediated restriction of Listeria spread otherwise imposed by COPII. Inhibition of Sec31A, Sec13, or Sar1 or brefeldin A treatment also perturbed the structure of cell-cell junctions. Collectively, these findings demonstrate an important role for COPII in controlling Listeria spread. We propose that COPII may act by delivering host proteins that generate tension at cell junctions. PMID:25529574

  9. Chemical chaperon 4-phenylbutyrate protects against the endoplasmic reticulum stress-mediated renal fibrosis in vivo and in vitro

    PubMed Central

    Wu, Cheng-Tien; Chen, Li-Ping; Huang, Jenq-Wen; Hung, Kuan-Yu; Chiang, Chih-Kang

    2016-01-01

    Renal tubulointerstitial fibrosis is the common and final pathologic change of kidney in end-stage renal disease. Interesting, endoplasmic reticulum (ER) stress is known to contribute to the pathophysiological mechanisms during the development of renal fibrosis. Here, we investigated the effects of chemical chaperon sodium 4-phenylbutyrate (4-PBA) on renal fibrosis in vivo and in vitro. In a rat unilateral ureteral obstruction (UUO) model, 4-PBA mimicked endogenous ER chaperon in the kidneys and significantly reduced glucose regulated protein 78 (GRP78), CCAAT/enhancer binding protein (C/EBP) homologous protein (CHOP), activating transcription factor 4 (ATF4), and phosphorylated JNK protein expressions as well as restored spliced X-box-binding protein 1 (XBP1) expressions in the kidneys of UUO rats. 4-PBA also attenuated the increases of α-smooth muscle actin (α-SMA), connective tissue growth factor (CTGF) protein expressions, tubulointerstitial fibrosis, and apoptosis in the kidneys of UUO rats. Moreover, transforming growth factor (TGF)-β markedly increased ER stress-associated molecules, profibrotic factors, and apoptotic markers in the renal tubular cells (NRK-52E), all of which could be significantly counteracted by 4-PBA treatment. 4-PBA also diminished TGF-β-increased CTGF promoter activity and CTGF mRNA expression in NRK-52E cells. Taken together, our results indicated that 4-PBA acts as an ER chaperone to ameliorate ER stress-induced renal tubular cell apoptosis and renal fibrosis. PMID:26959118

  10. Endoplasmic Reticulum Stress-Activated Transcription Factor ATF6α Requires the Disulfide Isomerase PDIA5 To Modulate Chemoresistance

    PubMed Central

    Higa, Arisa; Taouji, Said; Lhomond, Stéphanie; Jensen, Devon; Fernandez-Zapico, Martin E.; Simpson, Jeremy C.; Pasquet, Jean-Max; Schekman, Randy

    2014-01-01

    ATF6α, a membrane-anchored transcription factor from the endoplasmic reticulum (ER) that modulates the cellular response to stress as an effector of the unfolded-protein response (UPR), is a key player in the development of tumors of different origin. ATF6α activation has been linked to oncogenic transformation and tumor maintenance; however, the mechanism(s) underlying this phenomenon remains elusive. Here, using a phenotypic small interfering RNA (siRNA) screening, we identified a novel role for ATF6α in chemoresistance and defined the protein disulfide isomerase A5 (PDIA5) as necessary for ATF6α activation upon ER stress. PDIA5 contributed to disulfide bond rearrangement in ATF6α under stress conditions, thereby leading to ATF6α export from the ER and activation of its target genes. Further analysis of the mechanism demonstrated that PDIA5 promotes ATF6α packaging into coat protein complex II (COPII) vesicles and that the PDIA5/ATF6α activation loop is essential to confer chemoresistance on cancer cells. Genetic and pharmacological inhibition of the PDIA5/ATF6α axis restored sensitivity to the drug treatment. This work defines the mechanisms underlying the role of ATF6α activation in carcinogenesis and chemoresistance; furthermore, it identifies PDIA5 as a key regulator ATF6α-mediated cellular functions in cancer. PMID:24636989

  11. Sel1L is indispensable for mammalian endoplasmic reticulum-associated degradation, endoplasmic reticulum homeostasis, and survival

    PubMed Central

    Sun, Shengyi; Shi, Guojun; Han, Xuemei; Francisco, Adam B.; Ji, Yewei; Mendonça, Nuno; Liu, Xiaojing; Locasale, Jason W.; Simpson, Kenneth W.; Duhamel, Gerald E.; Kersten, Sander; Yates, John R.; Long, Qiaoming; Qi, Ling

    2014-01-01

    Suppressor/Enhancer of Lin-12-like (Sel1L) is an adaptor protein for the E3 ligase hydroxymethylglutaryl reductase degradation protein 1 (Hrd1) involved in endoplasmic reticulum-associated degradation (ERAD). Sel1L’s physiological importance in mammalian ERAD, however, remains to be established. Here, using the inducible Sel1L knockout mouse and cell models, we show that Sel1L is indispensable for Hrd1 stability, ER homeostasis, and survival. Acute loss of Sel1L leads to premature death in adult mice within 3 wk with profound pancreatic atrophy. Contrary to current belief, our data show that mammalian Sel1L is required for Hrd1 stability and ERAD function both in vitro and in vivo. Sel1L deficiency disturbs ER homeostasis, activates ER stress, attenuates translation, and promotes cell death. Serendipitously, using a biochemical approach coupled with mass spectrometry, we found that Sel1L deficiency causes the aggregation of both small and large ribosomal subunits. Thus, Sel1L is an indispensable component of the mammalian Hrd1 ERAD complex and ER homeostasis, which is essential for protein translation, pancreatic function, and cellular and organismal survival. PMID:24453213

  12. Reduced Endoplasmic Reticulum Luminal Calcium Links Saturated Fatty Acid-Mediated Endoplasmic Reticulum Stress and Cell Death in Liver Cells

    PubMed Central

    Wei, Yuren; Wang, Dong; Gentile, Christopher L.; Pagliassotti, Michael J.

    2010-01-01

    Chronic exposure to elevated free fatty acids, in particular long chain saturated fatty acids, provokes endoplasmic reticulum (ER) stress and cell death in a number of cell types. The perturbations to the ER that instigate ER stress and activation of the unfolded protein in response to fatty acids in hepatocytes have not been identified. The present study employed H4IIE liver cells and primary rat hepatocytes to examine the hypothesis that saturated fatty acids induce ER stress via effects on ER luminal calcium stores. Exposure of H4IIE liver cells and primary hepatocytes to palmitate and stearate reduced thapsigargin-sensitive calcium stores and biochemical markers of ER stress over similar time courses (6h). These changes preceded cell death, which was only observed at later time points (16h). Co-incubation with oleate prevented the reduction in calcium stores, induction of ER stress markers and cell death observed in response to palmitate. Inclusion of calcium chelators, BAPTA-AM or EGTA, reduced palmitate- and stearate-mediated enrichment of cytochrome c in post-mitochondrial supernatant fractions and cell death. These data suggest that redistribution of ER luminal calcium contributes to long chain saturated fatty acid-mediated ER stress and cell death. PMID:19444596

  13. Overlapping left ventricular restoration.

    PubMed

    Matsui, Yoshiro

    2009-06-01

    Cardiac transplantation, a final option of treatment for refractory heart failure, has not been a standard procedure in Japan especially, mainly because of the shortage of donors. However, surgical methods to restore native heart function, such as surgical ventricular restoration (SVR), are often effective for these cases. The Dor procedure has been used for ischemic cardiomyopathy cases presenting with broad akinetic segments. This is a fine method to exclude the scarred septum and to reduce the intraventricular cavity by encircling purse-string suture, but it may produce a postoperative spherical ventricular shape as a result of endoventricular patch repair. Also, partial left ventriculectomy is not recommended for non-ischemic dilated cardiomyopathy cases for now. A modification of these SVR and surgical approaches to functional mitral regurgitation has been named "overlapping ventriculoplasty" without endoventricular patch and resection of viable cardiac muscle, and "mitral complex reconstruction", which consists of mitral annuloplasty, papillary muscle approximation, and suspension. Although the long-term prognosis of these procedures is undetermined, they could be an important option, at least as an alternative bridge to transplantation. This review will describe the concepts and some technical aspects of these procedures for the end-stage heart. PMID:19474505

  14. Reparative dentistry or restorative dentistry?

    PubMed

    Small, Bruce W

    2008-01-01

    The real definition of restorative dentistry is found in the heart and hands of each individual restorative dentist. His or her training, continuing dental education, mentors, needs (financial and emotional), and style of practice all help to develop a philosophy of dental practice that affects daily restorative decisions. Depending on the factors described above, the decision to repair a tooth or change the environment and restore the tooth to a different shape, size, or color also may change. In recent years, patients' esthetic desires have become more of a factor than they were in previous decades. There are no exact written-tn-stone definitions of restorative dentistry, since the answers are operator-dependent and can vary. This column is meant to be food for thought and perhaps inspire discussion when dentists assemble for meetings or study clubs with the goal of delivering longer-lasting dentistry through a restorative dental practice. PMID:18348367

  15. Polychlorinated biphenyl quinone induces endoplasmic reticulum stress, unfolded protein response, and calcium release.

    PubMed

    Xu, Demei; Su, Chuanyang; Song, Xiufang; Shi, Qiong; Fu, Juanli; Hu, Lihua; Xia, Xiaomin; Song, Erqun; Song, Yang

    2015-06-15

    Organisms are able to respond to environmental insult to maintain cellular homeostasis, which include the activation of a wide range of cellular adaptive responses with tightly controlled mechanisms. The endoplasmic reticulum (ER) is an organelle responsible for protein folding and calcium storage. ER stress leads to the accumulation of unfolded proteins in the ER lumen. To be against or respond to this effect, cells have a comprehensive signaling system, called unfolded protein response (UPR), to restore homeostasis and normal ER function or activate the cell death program. Therefore, it is critical to understand how environmental insult regulates the ingredients of ER stress and UPR signalings. Previously, we have demonstrated that polychlorinated biphenyl (PCB) quinone caused oxidative stress, cytotoxicity, genotoxicity, and apoptosis in HepG2 cells. Here, we investigated the role of a PCB quinone, PCB29-pQ on ER stress, UPR, and calcium release. PCB29-pQ markedly increased the hallmark genes of ER stress, namely, glucose-regulated protein 78 (GRP78), GRP94, and C/EBP homologous protein (CHOP) on both protein and mRNA levels in HepG2 cells. We also confirmed PCB29-pQ induced ER morphological defects by using transmission electron microscopy. Moreover, PCB29-pQ induced intracellular calcium accumulation and calpain activity, which were significantly inhibited by the pretreatment of BAPTA-AM (Ca(2+) chelator). These results were correlated with the outcome that PCB29-pQ induces ER stress-related apoptosis through caspase family gene 12, while salubrinal and Z-ATAD-FMK (a specific inhibitor of caspase 12) partially ameliorated this effect, respectively. N-Acetyl-l-cysteine (NAC) scavenged ROS formation and consequently alleviated PCB29-pQ-induced expression of ER stress-related genes. In conclusion, our result demonstrated for the first time that PCB quinone leads to ROS-dependent induction of ER stress, and UPR and calcium release in HepG2 cells, and the

  16. Restoration of rivers and streams

    SciTech Connect

    Gore, J.A.

    1985-01-01

    All of the major topics which must be addressed when considering reclamation of a river ecosystem are detailed. Specific chapters deal with hydrologic considerations, including the estimation of meander patterns as well as geomorphic considerations of runoff patterns. Also covered are the preservation and restoration of water quality, as well as biological techniques for restoration of riparian vegetation, habitat enhancement for benthic invertebrates and fisheries, and methods for determining successful biotic restoration.

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

    PubMed

    Melnik, Bodo C

    2014-12-01

    Recent scientific interest in the pathogenesis of rosacea focuses on abnormally high facial skin levels of cathelicidin and the trypsin-like serine protease kallikrein 5 (KLK5) that cleaves the cathelicidin precursor protein into the bioactive fragment LL-37, which exerts crucial proinflammatory, angiogenic and antimicrobial activities. Furthermore, increased expression of toll-like receptor 2 (TLR2) has been identified in rosacea skin supporting the participation of the innate immune system. Notably, TLRs are expressed on sensory neurons and increase neuronal excitability linking TLR signalling to the transmission of neuroinflammatory responses. It is the intention of this viewpoint to present a unifying concept that links all known clinical trigger factors of rosacea such as UV irradiation, heat, skin irritants and special foods to one converging point: enhanced endoplasmic reticulum (ER) stress that activates the unfolded protein response (UPR). ER stress via upregulation of transcription factor ATF4 increases TLR2 expression, resulting in enhanced production of cathelicidin and KLK5 mediating downstream proinflammatory, angiogenic and antimicrobial signalling. The presented concept identifies rosacea trigger factors as environmental stressors that enhance the skin's ER stress response. Exaggerated cutaneous ER stress that stimulates the TLR2-driven inflammatory response may involve sebocytes, keratinocytes, monocyte-macrophages and sensory cutaneous neurons. Finally, all antirosacea drugs are proposed to attenuate the ER stress signalling cascade at some point. Overstimulated ER stress signalling may have evolutionarily evolved as a compensatory mechanism to balance impaired vitamin D-driven LL-37-mediated antimicrobial defenses due to lower exposure of UV-B irradiation of the northern Celtic population. PMID:25047092

  18. Inhibition of Endoplasmic Reticulum Stress Improves Mouse Embryo Development

    PubMed Central

    Zhang, Jin Yu; Diao, Yun Fei; Kim, Hong Rye; Jin, Dong Il

    2012-01-01

    X-box binding protein-1 (XBP-1) is an important regulator of a subset of genes during endoplasmic reticulum (ER) stress. In the current study, we analyzed endogenous XBP-1 expression and localization, with a view to determining the effects of ER stress on the developmental competency of preimplantation embryos in mice. Fluorescence staining revealed that functional XBP-1 is localized on mature oocyte spindles and abundant in the nucleus at the germinal vesicle (GV) stage. However, in preimplantation embryos, XBP-1 was solely detected in the cytoplasm at the one-cell stage. The density of XBP-1 was higher in the nucleus than the cytoplasm at the two-cell, four-cell, eight-cell, morula, and blastocyst stages. Furthermore, RT-PCR analysis confirmed active XBP-1 mRNA splicing at all preimplantation embryo stages, except the one-cell stage. Tunicamycin (TM), an ER stress inducer used as a positive control, promoted an increase in the density of nuclear XBP-1 at the one-cell and two-cell stages. Similarly, culture medium supplemented with 25 mM sorbitol displayed a remarkable increase active XBP-1 expression in the nuclei of 1-cell and 2-cell embryos. Conversely, high concentrations of TM or sorbitol led to reduced nuclear XBP-1 density and significant ER stress-induced apoptosis. Tauroursodeoxycholic acid (TUDCA), a known inhibitor of ER stress, improved the rate of two-cell embryo development to blastocysts by attenuating the expression of active XBP-1 protein in the nucleus at the two-cell stage. Our data collectively suggest that endogenous XBP-1 plays a role in normal preimplantation embryonic development. Moreover, XBP-1 splicing is activated to generate a functional form in mouse preimplantation embryos during culture stress. TUDCA inhibits hyperosmolar-induced ER stress as well as ER stress-induced apoptosis during mouse preimplantation embryo development. PMID:22808162

  19. Mitofusin 2 ablation increases endoplasmic reticulum-mitochondria coupling.

    PubMed

    Filadi, Riccardo; Greotti, Elisa; Turacchio, Gabriele; Luini, Alberto; Pozzan, Tullio; Pizzo, Paola

    2015-04-28

    The organization and mutual interactions between endoplasmic reticulum (ER) and mitochondria modulate key aspects of cell pathophysiology. Several proteins have been suggested to be involved in keeping ER and mitochondria at a correct distance. Among them, in mammalian cells, mitofusin 2 (Mfn2), located on both the outer mitochondrial membrane and the ER surface, has been proposed to be a physical tether between the two organelles, forming homotypic interactions and heterocomplexes with its homolog Mfn1. Recently, this widely accepted model has been challenged using quantitative EM analysis. Using a multiplicity of morphological, biochemical, functional, and genetic approaches, we demonstrate that Mfn2 ablation increases the structural and functional ER-mitochondria coupling. In particular, we show that in different cell types Mfn2 ablation or silencing increases the close contacts between the two organelles and strengthens the efficacy of inositol trisphosphate (IP3)-induced Ca(2+) transfer from the ER to mitochondria, sensitizing cells to a mitochondrial Ca(2+) overload-dependent death. We also show that the previously reported discrepancy between electron and fluorescence microscopy data on ER-mitochondria proximity in Mfn2-ablated cells is only apparent. By using a different type of morphological analysis of fluorescent images that takes into account (and corrects for) the gross modifications in mitochondrial shape resulting from Mfn2 ablation, we demonstrate that an increased proximity between the organelles is also observed by confocal microscopy when Mfn2 levels are reduced. Based on these results, we propose a new model for ER-mitochondria juxtaposition in which Mfn2 works as a tethering antagonist preventing an excessive, potentially toxic, proximity between the two organelles.

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

    PubMed

    Melnik, Bodo C

    2014-12-01

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

  1. Endoplasmic Reticulum Membrane Reorganization Is Regulated by Ionic Homeostasis

    PubMed Central

    Varadarajan, Shankar; Bampton, Edward T. W.; Pellecchia, Maurizio; Dinsdale, David; Willars, Gary B.; Cohen, Gerald M.

    2013-01-01

    Recently we described a new, evolutionarily conserved cellular stress response characterized by a reversible reorganization of endoplasmic reticulum (ER) membranes that is distinct from canonical ER stress and the unfolded protein response (UPR). Apogossypol, a putative broad spectrum BCL-2 family antagonist, was the prototype compound used to induce this ER membrane reorganization. Following microarray analysis of cells treated with apogossypol, we used connectivity mapping to identify a wide range of structurally diverse chemicals from different pharmacological classes and established their ability to induce ER membrane reorganization. Such structural diversity suggests that the mechanisms initiating ER membrane reorganization are also diverse and a major objective of the present study was to identify potentially common features of these mechanisms. In order to explore this, we used hierarchical clustering of transcription profiles for a number of chemicals that induce membrane reorganization and discovered two distinct clusters. One cluster contained chemicals with known effects on Ca2+ homeostasis. Support for this was provided by the findings that ER membrane reorganization was induced by agents that either deplete ER Ca2+ (thapsigargin) or cause an alteration in cellular Ca2+ handling (calmodulin antagonists). Furthermore, overexpression of the ER luminal Ca2+ sensor, STIM1, also evoked ER membrane reorganization. Although perturbation of Ca2+ homeostasis was clearly one mechanism by which some agents induced ER membrane reorganization, influx of extracellular Na+ but not Ca2+ was required for ER membrane reorganization induced by apogossypol and the related BCL-2 family antagonist, TW37, in both human and yeast cells. Not only is this novel, non-canonical ER stress response evolutionary conserved but so also are aspects of the mechanism of formation of ER membrane aggregates. Thus perturbation of ionic homeostasis is important in the regulation of ER

  2. Melatonin and endoplasmic reticulum stress: relation to autophagy and apoptosis.

    PubMed

    Fernández, Anna; Ordóñez, Raquel; Reiter, Russel J; González-Gallego, Javier; Mauriz, José L

    2015-10-01

    Endoplasmic reticulum (ER) is a dynamic organelle that participates in a number of cellular functions by controlling lipid metabolism, calcium stores, and proteostasis. Under stressful situations, the ER environment is compromised, and protein maturation is impaired; this causes misfolded proteins to accumulate and a characteristic stress response named unfolded protein response (UPR). UPR protects cells from stress and contributes to cellular homeostasis re-establishment; however, during prolonged ER stress, UPR activation promotes cell death. ER stressors can modulate autophagy which in turn, depending of the situation, induces cell survival or death. Interactions of different autophagy- and apoptosis-related proteins and also common signaling pathways have been found, suggesting an interplay between these cellular processes, although their dynamic features are still unknown. A number of pathologies including metabolic, neurodegenerative and cardiovascular diseases, cancer, inflammation, and viral infections are associated with ER stress, leading to a growing interest in targeting components of the UPR as a therapeutic strategy. Melatonin has a variety of antioxidant, anti-inflammatory, and antitumor effects. As such, it modulates apoptosis and autophagy in cancer cells, neurodegeneration and the development of liver diseases as well as other pathologies. Here, we review the effects of melatonin on the main ER stress mechanisms, focusing on its ability to regulate the autophagic and apoptotic processes. As the number of studies that have analyzed ER stress modulation by this indole remains limited, further research is necessary for a better understanding of the crosstalk between ER stress, autophagy, and apoptosis and to clearly delineate the mechanisms by which melatonin modulates these responses.

  3. Cortisol promotes endoplasmic glucose production via pyridine nucleotide redox.

    PubMed

    Wang, Zengmin; Mick, Gail J; Xie, Rongrong; Wang, Xudong; Xie, Xuemei; Li, Guimei; McCormick, Kenneth L

    2016-04-01

    Both increased adrenal and peripheral cortisol production, the latter governed by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), contribute to the maintenance of fasting blood glucose. In the endoplasmic reticulum (ER), the pyridine nucleotide redox state (NADP/NADPH) is dictated by the concentration of glucose-6-phosphate (G6P) and the coordinated activities of two enzymes, hexose-6-phosphate dehydrogenase (H6PDH) and 11β-HSD1. However, luminal G6P may similarly serve as a substrate for hepatic glucose-6-phophatase (G6Pase). A tacit belief is that the G6P pool in the ER is equally accessible to both H6PDH and G6Pase. Based on our inhibition studies and kinetic analysis in isolated rat liver microsomes, these two aforesaid luminal enzymes do share the G6P pool in the ER, but not equally. Based on the kinetic modeling of G6P flux, the ER transporter for G6P (T1) preferentially delivers this substrate to G6Pase; hence, the luminal enzymes do not share G6P equally. Moreover, cortisol, acting through 11β-HSD1, begets a more reduced pyridine redox ratio. By altering this luminal redox ratio, G6P flux through H6PDH is restrained, allowing more G6P for the competing enzyme G6Pase. And, at low G6P concentrations in the ER lumen, which occur during fasting, this acute cortisol-induced redox adjustment promotes glucose production. This reproducible cortisol-driven mechanism has been heretofore unrecognized. PMID:26860459

  4. Longevity of Posterior Composite Restorations

    PubMed Central

    Opdam, N.J.M.; van de Sande, F.H.; Bronkhorst, E.; Cenci, M.S.; Bottenberg, P.; Pallesen, U.; Gaengler, P.; Lindberg, A.; Huysmans, M.C.D.N.J.M.; van Dijken, J.W.

    2014-01-01

    The aim of this meta-analysis, based on individual participant data from several studies, was to investigate the influence of patient-, materials-, and tooth-related variables on the survival of posterior resin composite restorations. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a search resulting in 12 longitudinal studies of direct posterior resin composite restorations with at least 5 years’ follow-up. Original datasets were still available, including placement/failure/censoring of restorations, restored surfaces, materials used, reasons for clinical failure, and caries-risk status. A database including all restorations was constructed, and a multivariate Cox regression method was used to analyze variables of interest [patient (age; gender; caries-risk status), jaw (upper; lower), number of restored surfaces, resin composite and adhesive materials, and use of glass-ionomer cement as base/liner (present or absent)]. The hazard ratios with respective 95% confidence intervals were determined, and annual failure rates were calculated for subgroups. Of all restorations, 2,816 (2,585 Class II and 231 Class I) were included in the analysis, of which 569 failed during the observation period. Main reasons for failure were caries and fracture. The regression analyses showed a significantly higher risk of failure for restorations in high-caries-risk individuals and those with a higher number of restored surfaces. PMID:25048250

  5. Endoplasmic filaments generate the motive force for rotational streaming in Nitella.

    PubMed

    Allen, N S

    1974-10-01

    The streaming endoplasm of characean cells has been shown to contain previously unreported endoplasmic filaments along which bending waves are observed under the light microscope using special techniques. The bending waves are similar to those propagated along sperm tails causing propulsion of sperm. In Nitella there is reason to believe that nearly all of the filaments are anchored in the cortex and that their beating propels the endoplasm in which they are suspended. This hypothesis is supported by calculations in which typical and average wave parameters have been inserted into the classical hydrodynamic equations derived for sperm tail bending waves. These calculations come within an order of magnitude of predicting the velocity of streaming and they show that waves of the character described, propagated along an estimated 52 m of endoplasmic filaments per cell, must generate a total motive force per cell within less than an order of magnitude of the forces measured experimentally by others. If we assume that undulating filaments produce the force driving the endoplasm, then the method described for measuring the motive force could lead to a lower than actual value for the motive force, since both centrifugation and vacuolar perfusion would reverse the orientation of some filaments. Observations of the initiation of particle translation in association with the filaments suggest that particle transport and wave propagation, which occur at the same velocity, may both be dependent on the same process. The possibility that some form of contractility provides the motive force for filament flection and particle transport is discussed.

  6. ENDOPLASMIC FILAMENTS GENERATE THE MOTIVE FORCE FOR ROTATIONAL STREAMING IN NITELLA

    PubMed Central

    Allen, Nina Strömgren

    1974-01-01

    The streaming endoplasm of characean cells has been shown to contain previously unreported endoplasmic filaments along which bending waves are observed under the light microscope using special techniques. The bending waves are similar to those propagated along sperm tails causing propulsion of sperm. In Nitella there is reason to believe that nearly all of the filaments are anchored in the cortex and that their beating propels the endoplasm in which they are suspended. This hypothesis is supported by calculations in which typical and average wave parameters have been inserted into the classical hydrodynamic equations derived for sperm tail bending waves. These calculations come within an order of magnitude of predicting the velocity of streaming and they show that waves of the character described, propagated along an estimated 52 m of endoplasmic filaments per cell, must generate a total motive force per cell within less than an order of magnitude of the forces measured experimentally by others. If we assume that undulating filaments produce the force driving the endoplasm, then the method described for measuring the motive force could lead to a lower than actual value for the motive force, since both centrifugation and vacuolar perfusion would reverse the orientation of some filaments. Observations of the initiation of particle translation in association with the filaments suggest that particle transport and wave propagation, which occur at the same velocity, may both be dependent on the same process. The possibility that some form of contractility provides the motive force for filament flection and particle transport is discussed. PMID:4608919

  7. The deadly connection between endoplasmic reticulum, Ca2+, protein synthesis, and the endoplasmic reticulum stress response in malignant glioma cells

    PubMed Central

    Johnson, Guyla G.; White, Misti C.; Wu, Jian-He; Vallejo, Matthew; Grimaldi, Maurizio

    2014-01-01

    Background The endoplasmic reticulum (ER) is involved in Ca2+ signaling and protein processing. Accumulation of unfolded proteins following ER Ca2+ depletion triggers the ER stress response (ERSR), which facilitates protein folding and removal of damaged proteins and can induce cell death. Unfolded proteins bind to chaperones, such as the glucose-regulated protein (GRP)78 and cause the release of GRP78-repressed proteins executing ERSR. Methods Several glioma cell lines and primary astrocytes were used to analyze ERSR using standard western blots, reverse transcription–PCR, viability assays, and single cell Ca2+ imaging. Results ERSR induction with thapsigargin results in a more intense ERSR associated with a larger loss of ER Ca2+, activation of ER-associated caspases (4/12) and caspase 3, and a higher rate of malignant glioma cell death than in normal glial cells. Malignant glioma cells have higher levels of protein synthesis and expression of the translocon (a component of the ribosomal complex, guiding protein entry in the ER), the activity of which is associated with the loss of ER Ca2+. Our experiments confirm increased expression of the translocon in malignant glioma cells. In addition, blockade of the ribosome-translocon complex with agents differently affecting translocon Ca2+ permeability causes opposite effects on ERSR deployment and death of malignant glioma cells. Conclusions Excessive ER Ca2+ loss due to translocon activity appears to be responsible for the enhancement of ERSR, leading to the death of glioma cells. The results reveal a characteristic of malignant glioma cells that could be exploited to develop new therapeutic strategies to treat incurable glial malignancies. PMID:24569545

  8. Nodal endoplasmic reticulum, a specialized form of endoplasmic reticulum found in gravity-sensing root tip columella cells

    NASA Technical Reports Server (NTRS)

    Zheng, H. Q.; Staehelin, L. A.

    2001-01-01

    The endoplasmic reticulum (ER) of columella root cap cells has been postulated to play a role in gravity sensing. We have re-examined the ultrastructure of columella cells in tobacco (Nicotiana tabacum) root tips preserved by high-pressure freezing/freeze-substitution techniques to gain more precise information about the organization of the ER in such cells. The most notable findings are: the identification of a specialized form of ER, termed "nodal ER," which is found exclusively in columella cells; the demonstration that the bulk of the ER is organized in the form of a tubular network that is confined to a peripheral layer under the plasma membrane; and the discovery that this ER-rich peripheral region excludes Golgi stacks, vacuoles, and amyloplasts but not mitochondria. Nodal ER domains consist of an approximately 100-nm-diameter central rod composed of oblong subunits to which usually seven sheets of rough ER are attached along their margins. These domains form patches at the interface between the peripheral ER network and the ER-free central region of the cells, and they occupy defined positions within central and flanking columella cells. Over one-half of the nodal ER domains are located along the outer tangential walls of the flanking cells. Cytochalasin D and latrunculin A cause an increase in size and a decrease in numbers of nodal ER domains. We postulate that the nodal ER membranes locally modulate the gravisensing signals produced by the sedimenting amyloplasts, and that the confinement of all ER membranes to the cell periphery serves to enhance the sedimentability of the amyloplasts in the central region of columella cells.

  9. 15 CFR 990.56 - Restoration selection-use of a Regional Restoration Plan or existing restoration project.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 3 2013-01-01 2013-01-01 false Restoration selection-use of a..., DEPARTMENT OF COMMERCE OIL POLLUTION ACT REGULATIONS NATURAL RESOURCE DAMAGE ASSESSMENTS Restoration Planning Phase § 990.56 Restoration selection—use of a Regional Restoration Plan or existing restoration...

  10. 15 CFR 990.56 - Restoration selection-use of a Regional Restoration Plan or existing restoration project.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 3 2012-01-01 2012-01-01 false Restoration selection-use of a..., DEPARTMENT OF COMMERCE OIL POLLUTION ACT REGULATIONS NATURAL RESOURCE DAMAGE ASSESSMENTS Restoration Planning Phase § 990.56 Restoration selection—use of a Regional Restoration Plan or existing restoration...

  11. 15 CFR 990.56 - Restoration selection-use of a Regional Restoration Plan or existing restoration project.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 3 2014-01-01 2014-01-01 false Restoration selection-use of a..., DEPARTMENT OF COMMERCE OIL POLLUTION ACT REGULATIONS NATURAL RESOURCE DAMAGE ASSESSMENTS Restoration Planning Phase § 990.56 Restoration selection—use of a Regional Restoration Plan or existing restoration...

  12. Restorative Nurse Assistant. Instructor Guide.

    ERIC Educational Resources Information Center

    Missouri Univ., Columbia. Instructional Materials Lab.

    This curriculum material covers the basic orientation and necessary skills which would enable the practicing Certified Nurse Assistant to be trained as a Restorative Nurse Assistant. The shift in emphasis from maintenance care to restorative care in the long-term care setting has created a need for trained paraprofessionals who are competent in…

  13. Restorative Justice in School Communities.

    ERIC Educational Resources Information Center

    Karp, David R.; Breslin, Beau

    2001-01-01

    Explores the recent implementation of restorative justice practices in Minnesota, Colorado, and Pennsylvania school communities, examining how their approaches can address substance abuse problems and offer alternatives to zero-tolerance policies. The three programs are committed to the idea that restoration is a more appropriate educational tool…

  14. Restorative biological processes and health

    PubMed Central

    Robles, Theodore F.; Carroll, Judith E.

    2011-01-01

    Research on psychological influences on physiology primarily focuses on biological responses during stressful challenges, and how those responses can become dysregulated with prolonged or repeated exposure to stressful circumstances. At the same time, humans spend considerable time recovering from those challenges, and a host of biological processes involved in restoration and repair take place during normal, non-stressed activities. We review restorative biological processes and evidence for links between psychosocial factors and several restorative processes including sleep, wound healing, antioxidant production, DNA repair, and telomerase function. Across these biological processes, a growing body of evidence suggests that experiencing negative emotional states, including acute and chronic stress, depressive symptoms, and individual differences in negative affectivity and hostility, can influence these restorative processes. This review calls attention to restorative processes as fruitful mechanisms and outcomes for future biobehavioral research. PMID:21927619

  15. The Role of Endoplasmic Reticulum Stress and Unfolded Protein Response in Atherosclerosis.

    PubMed

    Ivanova, Ekaterina A; Orekhov, Alexander N

    2016-02-01

    Pathogenesis of atherosclerosis is a complex process involving several metabolic and signalling pathways. Accumulating evidence demonstrates that endoplasmic reticulum stress and associated apoptosis can be induced in the pathological conditions of atherosclerotic lesions and contribute to the disease progression. Notably, they may play a role in the development of vulnerable plaques that induce thrombosis and are therefore especially dangerous. Endoplasmic reticulum stress response is regulated by several signaling mechanisms that involve protein kinases and transcription factors. Some of these molecules can be regarded as potential therapeutic targets to improve treatment of atherosclerosis. In this review we will discuss the role of endoplasmic reticulum stress and apoptosis in atherosclerosis development in different cell types and summarize the current knowledge on potential therapeutic agents targeting molecules regulating these pathways and their possible use for anti-atherosclerotic therapy.

  16. Deubiquitination, a new player in Golgi to endoplasmic reticulum retrograde transport.

    PubMed

    Cohen, Mickaël; Stutz, Françoise; Dargemont, Catherine

    2003-12-26

    Modification by ubiquitin plays a major role in a broad array of cellular functions. Although reversal of this process, deubiquitination, likely represents an important regulatory step contributing to cellular homeostasis, functions of deubiquitination enzymes still remain poorly characterized. We have previously shown that the ubiquitin protease Ubp3p requires a co-factor, Bre5p, to specifically deubiquitinate the coat protein complex II (COPII) subunit Sec23p, which is involved in anterograde transport between endoplasmic reticulum and Golgi compartments. In the present report, we show that disruption of BRE5 gene also led to a defect in the retrograde transport from the Golgi to the endoplasmic reticulum. Further analysis indicate that the COPI subunit beta'-COP represents another substrate of the Ubp3p.Bre5p complex. All together, our results indicate that the Ubp3p.Bre5p deubiquitination complex co-regulates anterograde and retrograde transports between endoplasmic reticulum and Golgi compartments.

  17. [Role of endoplasmic reticulum-plasma membrane junctions in intracellular calcium homeostasis and cardiovascular disease].

    PubMed

    Zhao, Ming; Jia, Hang-Huan; Xu, Man; Yu, Xiao-Jiang; Liu, Long-Zhu; Zang, Wei-Jin

    2016-08-25

    Calcium overload is one of the important mechanisms of cardiovascular disease. Endoplasmic reticulum is an important organelle which regulates intracellular calcium homeostasis by uptake, storage and mobilization of calcium. So it plays a critical role in regulation of intracellular calcium homeostasis. Endoplasmic reticulum, which is widely distributed in cytoplasm, has a large number of membrane junction sites. Recent studies have reported that these junction sites are distributed on plasma membrane and organelle membranes (mitochondria, lysosomes, Golgi apparatus, etc.), separately. They could form complexes to regulate calcium transport. In this review, we briefly outlined the recent research progresses of endoplasmic reticulum-plasma membrane junctions in intracellular calcium homeostasis and cardiovascular disease, which may offer a new strategy for prevention and treatment of cardiovascular disease. PMID:27546511

  18. The Role of Endoplasmic Reticulum Stress and Unfolded Protein Response in Atherosclerosis

    PubMed Central

    Ivanova, Ekaterina A.; Orekhov, Alexander N.

    2016-01-01

    Pathogenesis of atherosclerosis is a complex process involving several metabolic and signalling pathways. Accumulating evidence demonstrates that endoplasmic reticulum stress and associated apoptosis can be induced in the pathological conditions of atherosclerotic lesions and contribute to the disease progression. Notably, they may play a role in the development of vulnerable plaques that induce thrombosis and are therefore especially dangerous. Endoplasmic reticulum stress response is regulated by several signaling mechanisms that involve protein kinases and transcription factors. Some of these molecules can be regarded as potential therapeutic targets to improve treatment of atherosclerosis. In this review we will discuss the role of endoplasmic reticulum stress and apoptosis in atherosclerosis development in different cell types and summarize the current knowledge on potential therapeutic agents targeting molecules regulating these pathways and their possible use for anti-atherosclerotic therapy. PMID:26840309

  19. Sequential NO production by mitochondria and endoplasmic reticulum during induced apoptosis.

    PubMed

    Bustamante, Juanita; Bersier, Geraldine; Badin, Romina Aron; Cymeryng, Cora; Parodi, Armando; Boveris, Alberto

    2002-05-01

    Early stages of rat thymocyte apoptosis measured as annexin-V positive events and induced by methylprednisolone (MPS), etoposide, and thapsigargin, showed a sequential increase in nitric oxide (NO) production by mitochondrial and endoplasmic reticulum membranes. Thapsigargin induced the highest NO production, a sevenfold increase as compared with untreated thymocytes, in mitochondrial and microsomal membranes. MPS and etoposide were equally effective in increasing NO production by mitochondrial membranes by a factor of 4-5, with only a slight increase in NO production by endoplasmic reticulum membranes. Western blot analysis of both types of membrane indicated that a nitric oxide synthase (NOS) isoenzyme is present in mitochondrial membranes and reacts with antibodies to i-NOS (type II), while reactivity to antibodies to e-NOS (type III) was restricted to endoplasmic reticulum. The participation of endoplasmic reticulum during apoptosis was further determined by alterations in UDP-Glucosyltransferase (UDP-GT) and NADPH cytochrome P450 reductase. Increased UDP-GT activity was observed after thapsigargin treatment, and no changes were found after treatment with etoposide or MPS. NADPH cytochrome P450 reductase activity markedly decreased during apoptosis, being stronger after thapsigargin treatment. The latest stage of the apoptotic process was measured by caspase activities. Caspase 3 activity was markedly increased by the three apoptosis inducers; caspase 6 was only activated by MPS and etoposide, while caspase 8 was not activated by any of these inducers. It is clear that mitochondria and endoplasmic reticulum are involved in thapsigargin induced thymocyte apoptosis. Meanwhile, other thymocyte apoptotic pathways, such as those induced by MPS or etoposide, seem to centrally involve mitochondria but not endoplasmic reticulum. PMID:12009851

  20. Sequential NO production by mitochondria and endoplasmic reticulum during induced apoptosis.

    PubMed

    Bustamante, Juanita; Bersier, Geraldine; Badin, Romina Aron; Cymeryng, Cora; Parodi, Armando; Boveris, Alberto

    2002-05-01

    Early stages of rat thymocyte apoptosis measured as annexin-V positive events and induced by methylprednisolone (MPS), etoposide, and thapsigargin, showed a sequential increase in nitric oxide (NO) production by mitochondrial and endoplasmic reticulum membranes. Thapsigargin induced the highest NO production, a sevenfold increase as compared with untreated thymocytes, in mitochondrial and microsomal membranes. MPS and etoposide were equally effective in increasing NO production by mitochondrial membranes by a factor of 4-5, with only a slight increase in NO production by endoplasmic reticulum membranes. Western blot analysis of both types of membrane indicated that a nitric oxide synthase (NOS) isoenzyme is present in mitochondrial membranes and reacts with antibodies to i-NOS (type II), while reactivity to antibodies to e-NOS (type III) was restricted to endoplasmic reticulum. The participation of endoplasmic reticulum during apoptosis was further determined by alterations in UDP-Glucosyltransferase (UDP-GT) and NADPH cytochrome P450 reductase. Increased UDP-GT activity was observed after thapsigargin treatment, and no changes were found after treatment with etoposide or MPS. NADPH cytochrome P450 reductase activity markedly decreased during apoptosis, being stronger after thapsigargin treatment. The latest stage of the apoptotic process was measured by caspase activities. Caspase 3 activity was markedly increased by the three apoptosis inducers; caspase 6 was only activated by MPS and etoposide, while caspase 8 was not activated by any of these inducers. It is clear that mitochondria and endoplasmic reticulum are involved in thapsigargin induced thymocyte apoptosis. Meanwhile, other thymocyte apoptotic pathways, such as those induced by MPS or etoposide, seem to centrally involve mitochondria but not endoplasmic reticulum.

  1. "I Was Dead Restorative Today": From Restorative Justice to Restorative Approaches in School

    ERIC Educational Resources Information Center

    McCluskey, G.; Lloyd, G.; Stead, J.; Kane, J.; Riddell, S.; Weedon, E.

    2008-01-01

    This paper explores definitions and understandings of restorative practices in education. It offers a critique of current theoretical models of restorative justice originally derived from the criminal justice system and now becoming popular in educational settings. It questions the appropriateness of these concepts as they are being introduced to…

  2. The density of the cell sap and endoplasm of Nitellopsis and Chara

    NASA Technical Reports Server (NTRS)

    Wayne, R.; Staves, M. P.

    1991-01-01

    We measured the densities of the cell sap, endoplasm and cell wall of Nitellopsis obtusa and Chara corallina using interference microscopy, refractometry, immersion refractometry, equilibrium sedimentation and chemical microanalysis techniques. These values are important for the determination of many rheological properties of the cytoplasm as well as for understanding buoyancy regulation, dispersal mechanisms and how cells respond to gravity. The average densities of the cell sap, endoplasm and cell wall are 1,006.9, 1,016.7 and 1,371 kg m-3 for Nitellopsis and 1,005.0, 1,013.9, and 1,355.3 kg m-3 for Chara.

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

    PubMed

    Yang, Jian-Wen; Hu, Zhi-Ping

    2015-08-01

    Cerebral ischemia triggers secondary ischemia/reperfusion injury and endoplasmic reticulum stress initiates cell apoptosis. However, the regulatory mechanism of the signaling pathway remains unclear. We hypothesize that the regulatory mechanisms are mediated by the protein kinase-like endoplasmic reticulum kinase/eukaryotic initiation factor 2α in the endoplasmic reticulum stress signaling pathway. To verify this hypothesis, we occluded the middle cerebral artery in rats to establish focal cerebral ischemia/reperfusion model. Results showed that the expression levels of protein kinase-like endoplasmic reticulum kinase and caspase-3, as well as the phosphorylation of eukaryotic initiation factor 2α, were increased after ischemia/reperfusion. Administration of atorvastatin decreased the expression of protein kinase-like endoplasmic reticulum kinase, caspase-3 and phosphorylated eukaryotic initiation factor 2α, reduced the infarct volume and improved ultrastructure in the rat brain. After salubrinal, the specific inhibitor of phosphorylated eukaryotic initiation factor 2α was given into the rats intragastrically, the expression levels of caspase-3 and phosphorylated eukaryotic initiation factor 2α in the were decreased, a reduction of the infarct volume and less ultrastructural damage were observed than the untreated, ischemic brain. However, salubrinal had no impact on the expression of protein kinase-like endoplasmic reticulum kinase. Experimental findings indicate that atorvastatin inhibits endoplasmic reticulum stress and exerts neuroprotective effects. The underlying mechanisms of attenuating ischemia/reperfusion injury are associated with the protein kinase-like endoplasmic reticulum kinase/eukaryotic initiation factor 2α/caspase-3 pathway. PMID:26487850

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

    PubMed Central

    Yang, Jian-wen; Hu, Zhi-ping

    2015-01-01

    Cerebral ischemia triggers secondary ischemia/reperfusion injury and endoplasmic reticulum stress initiates cell apoptosis. However, the regulatory mechanism of the signaling pathway remains unclear. We hypothesize that the regulatory mechanisms are mediated by the protein kinase-like endoplasmic reticulum kinase/eukaryotic initiation factor 2α in the endoplasmic reticulum stress signaling pathway. To verify this hypothesis, we occluded the middle cerebral artery in rats to establish focal cerebral ischemia/reperfusion model. Results showed that the expression levels of protein kinase-like endoplasmic reticulum kinase and caspase-3, as well as the phosphorylation of eukaryotic initiation factor 2α, were increased after ischemia/reperfusion. Administration of atorvastatin decreased the expression of protein kinase-like endoplasmic reticulum kinase, caspase-3 and phosphorylated eukaryotic initiation factor 2α, reduced the infarct volume and improved ultrastructure in the rat brain. After salubrinal, the specific inhibitor of phosphorylated eukaryotic initiation factor 2α was given into the rats intragastrically, the expression levels of caspase-3 and phosphorylated eukaryotic initiation factor 2α in the were decreased, a reduction of the infarct volume and less ultrastructural damage were observed than the untreated, ischemic brain. However, salubrinal had no impact on the expression of protein kinase-like endoplasmic reticulum kinase. Experimental findings indicate that atorvastatin inhibits endoplasmic reticulum stress and exerts neuroprotective effects. The underlying mechanisms of attenuating ischemia/reperfusion injury are associated with the protein kinase-like endoplasmic reticulum kinase/eukaryotic initiation factor 2α/caspase-3 pathway. PMID:26487850

  5. CRITERIA FOR PRIORITIZATION OF ECOSYSTEM RESTORATION

    EPA Science Inventory

    Prioritization of ecosystem restoration measures is important for state and federal agencies, watershed coalitions, science advisory boards and other groups responsible for decision-making regarding restoration activities. Although widely utilized, the term "restoration prioriti...

  6. Fernald restoration: ecologists and engineers integrate restoration and cleanup

    SciTech Connect

    Woods, Eric; Homer, John

    2002-07-15

    As cleanup workers excavate pits and tear down buildings at the Fernald site in southwest Ohio, site ecologists are working side-by-side to create thriving wetlands and develop the early stages of forest, prairie, and savanna ecosystems to restore natural resources that were impacted by years of site operations. In 1998, the U.S. Department of Energy-Fernald Office (DOE-FN) and its cleanup contractor, Fluor Fernald, Inc., initiated several ecological restoration projects in perimeter areas of the site (e.g., areas not used for or impacted by uranium processing or waste management). The projects are part of Fernald's final land use plan to restore natural resources over 904 acres of the 1,050-acre site. Pete Yerace, the DOE-FN Natural Resource Trustee representative is working with the Fernald Natural Resource Trustees in an oversight role to resolve the state of Ohio's 1986 claim against DOE for injuries to natural resources. Fluor Fernald, Inc., and DOE-FN developed the ''Natural Resource Restoration Plan'', which outlines 15 major restoration projects for the site and will restore injured natural resources at the site. In general, Fernald's plan includes grading to maximize the formation of wetlands or expanded floodplain, amending soil where topsoil has been removed during excavation, and establishing native vegetation throughout the site. Today, with cleanup over 35 percent complete and site closure targeted for 2006, Fernald is entering a new phase of restoration that involves heavily remediated areas. By working closely with engineers and cleanup crews, site ecologists can take advantage of remediation fieldwork (e.g., convert an excavated depression into a wetland) and avoid unnecessary costs and duplication. This collaboration has also created opportunities for relatively simple and inexpensive restoration of areas that were discovered during ongoing remediation. To ensure the survival of the plant material in heavily disturbed soils, Fernald will use

  7. Endoplasmic reticulum stress sensor protein kinase R-like endoplasmic reticulum kinase (PERK) protects against pressure overload-induced heart failure and lung remodeling.

    PubMed

    Liu, Xiaoyu; Kwak, Dongmin; Lu, Zhongbing; Xu, Xin; Fassett, John; Wang, Huan; Wei, Yidong; Cavener, Douglas R; Hu, Xinli; Hall, Jennifer; Bache, Robert J; Chen, Yingjie

    2014-10-01

    Studies have reported that development of congestive heart failure is associated with increased endoplasmic reticulum stress. Double stranded RNA-activated protein kinase R-like endoplasmic reticulum kinase (PERK) is a major transducer of the endoplasmic reticulum stress response and directly phosphorylates eukaryotic initiation factor 2α, resulting in translational attenuation. However, the physiological effect of PERK on congestive heart failure development is unknown. To study the effect of PERK on ventricular structure and function, we generated inducible cardiac-specific PERK knockout mice. Under unstressed conditions, cardiac PERK knockout had no effect on left ventricular mass, or its ratio to body weight, cardiomyocyte size, fibrosis, or left ventricular function. However, in response to chronic transverse aortic constriction, PERK knockout mice exhibited decreased ejection fraction, increased left ventricular fibrosis, enhanced cardiomyocyte apoptosis, and exacerbated lung remodeling in comparison with wild-type mice. PERK knockout also dramatically attenuated cardiac sarcoplasmic reticulum Ca(2+)-ATPase expression in response to aortic constriction. Our findings suggest that PERK is required to protect the heart from pressure overload-induced congestive heart failure.

  8. Biological restorations using tooth fragments.

    PubMed

    Busato, A L; Loguercio, A D; Barbosa, A N; Sanseverino, M do C; Macedo, R P; Baldissera, R A

    1998-02-01

    A "biological" restoration technique using dental fragments and adhesive materials is described. These fragments were obtained from extracted human teeth which had been previously sterilized and stored in a tooth bank. The advantages are: the use of extracted teeth as restorative material, esthetics, and treatment cost. The positive sensation of having back the missing tooth was the most mentioned comment among patients. The disadvantages are: the difficulty of obtaining teeth with the needed characteristics, problems of making an indirect restoration, matching the original color, and the non-acceptance by some patients who consider it strange to have other people's teeth placed in their mouths.

  9. Brain endoplasmic reticulum stress mechanistically distinguishes the saline-intake and hypertensive response to deoxycorticosterone acetate-salt.

    PubMed

    Jo, Fusakazu; Jo, Hiromi; Hilzendeger, Aline M; Thompson, Anthony P; Cassell, Martin D; Rutkowski, D Thomas; Davisson, Robin L; Grobe, Justin L; Sigmund, Curt D

    2015-06-01

    Endoplasmic reticulum stress has become an important mechanism in hypertension. We examined the role of endoplasmic reticulum stress in mediating the increased saline-intake and hypertensive effects in response to deoxycorticosterone acetate (DOCA)-salt. Intracerebroventricular delivery of the endoplasmic reticulum stress-reducing chemical chaperone tauroursodeoxycholic acid did not affect the magnitude of hypertension, but markedly decreased saline-intake in response to DOCA-salt. Increased saline-intake returned after tauroursodeoxycholic acid was terminated. Decreased saline-intake was also observed after intracerebroventricular infusion of 4-phenylbutyrate, another chemical chaperone. Immunoreactivity to CCAAT homologous binding protein, a marker of irremediable endoplasmic reticulum stress, was increased in the subfornical organ and supraoptic nucleus of DOCA-salt mice, but the signal was absent in control and CCAAT homologous binding protein-deficient mice. Electron microscopy revealed abnormalities in endoplasmic reticulum structure (decrease in membrane length, swollen membranes, and decreased ribosome numbers) in the subfornical organ consistent with endoplasmic reticulum stress. Subfornical organ-targeted adenoviral delivery of GRP78, a resident endoplasmic reticulum chaperone, decreased DOCA-salt-induced saline-intake. The increase in saline-intake in response to DOCA-salt was blunted in CCAAT homologous binding protein-deficient mice, but these mice exhibited a normal hypertensive response. We conclude that (1) brain endoplasmic reticulum stress mediates the saline-intake, but not blood pressure response to DOCA-salt, (2) DOCA-salt causes endoplasmic reticulum stress in the subfornical organ, which when attenuated by GRP78 blunts saline-intake, and (3) CCAAT homologous binding protein may play a functional role in DOCA-salt-induced saline-intake. The results suggest a mechanistic distinction between the importance of endoplasmic reticulum stress in

  10. Optimum constrained image restoration filters

    NASA Technical Reports Server (NTRS)

    Riemer, T. E.; Mcgillem, C. D.

    1974-01-01

    The filter was developed in Hilbert space by minimizing the radius of gyration of the overall or composite system point-spread function subject to constraints on the radius of gyration of the restoration filter point-spread function, the total noise power in the restored image, and the shape of the composite system frequency spectrum. An iterative technique is introduced which alters the shape of the optimum composite system point-spread function, producing a suboptimal restoration filter which suppresses undesirable secondary oscillations. Finally this technique is applied to multispectral scanner data obtained from the Earth Resources Technology Satellite to provide resolution enhancement. An experimental approach to the problems involving estimation of the effective scanner aperture and matching the ERTS data to available restoration functions is presented.

  11. Kondolf Diagram for River Restoration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rehabilitation, protection, and management of riverine backwaters (floodplain aquatic habitats that are seasonally or periodically connected to the main channel) are becoming increasingly common. General criteria for selecting restoration goals and evaluating alternative designs are lacking. An app...

  12. Esthetic restoration of primary incisors.

    PubMed

    Carranza, F; García-Godoy, F

    1999-04-01

    A simple and esthetic technique for restoring cariously involved primary maxillary incisors is described. The technique includes mini-pins, a preformed celluloid crown and resin-based composite. PMID:10477982

  13. [Combined orthodontic and restorative treatment].

    PubMed

    Kuijpers, M A R; Loomans, B

    2015-11-01

    In patients with agenesis or enamel anomalies in anterior teeth combined orthodontic and restorative treatment is often necessary to achieve an optimal aesthetic result. How both can best be achieved, but also how to maintain the result, requires communication between the dentist and the orthodontist. The orthodontic treatment plan needs to be established in cooperation with the dentist who will carry out the restorative treatment while the patient is at a young age. Since with these young patients, who are still growing craniofacially and whose teeth are still developing, possible future restorative and/or orthodontic treatment, as well as the means of orthodontic retention, need to be included in the treatment plan. In cleft palate patients, it is also important that methods of orthodontic retention of maxillary arch width are given timely attention in the restorative treatment plan because it is especially vulnerable to relapse. PMID:26568998

  14. Basic research for environmental restoration

    SciTech Connect

    Not Available

    1990-12-01

    The Department of Energy (DOE) is in the midst of a major environmental restoration effort to reduce the health and environmental risks resulting from past waste management and disposal practices at DOE sites. This report describes research needs in environmental restoration and complements a previously published document, DOE/ER-0419, Evaluation of Mid-to-Long Term Basic Research for Environmental Restoration. Basic research needs have been grouped into five major categories patterned after those identified in DOE/ER-0419: (1) environmental transport and transformations; (2) advanced sampling, characterization, and monitoring methods; (3) new remediation technologies; (4) performance assessment; and (5) health and environmental effects. In addition to basic research, this document deals with education and training needs for environmental restoration. 2 figs., 6 tabs.

  15. Temperature-compensating dc restorer

    NASA Technical Reports Server (NTRS)

    Thomas, H. M.

    1980-01-01

    Circuit provides stable references restoration in addition to temperature compensation. Possible TV monitor applications include traffic and security surveillance systems, where cameras are subject to environmental extremes, as in unheated warehouses or outdoors.

  16. Chlorhexidine-induced apoptosis or necrosis in L929 fibroblasts: A role for endoplasmic reticulum stress

    SciTech Connect

    Faria, Gisele; Cardoso, Cristina R.B.; Larson, Roy E.; Silva, Joao S.; Rossi, Marcos A.

    2009-01-15

    Chlorhexidine (CHX), widely used as antiseptic and therapeutic agent in medicine and dentistry, has a toxic effect both in vivo and in vitro. The intrinsic mechanism underlying CHX-induced cytotoxicity in eukaryotic cells is, however, still unknown. A recent study from our laboratory has suggested that CHX may induce death in cultured L929 fibroblasts via endoplasmic reticulum (ER) stress. This hypothesis was further tested by means of light and electron microscopy, quantification of apoptosis and necrosis by flow cytometry, fluorescence visualization of the cytoskeleton and endoplasmic reticulum, and evaluation of the expression of 78-kDa glucose-regulated protein 78 (Grp78), a marker of activation of the unfolded protein response (UPR) in cultured L929 fibroblasts. Our finding showing increased Grp 78 expression in CHX-treated cells and the results of flow cytometry, cytoskeleton and endoplasmic reticulum fluorescence visualization, and scanning and transmission electron microscopy allowed us to suggest that CHX elicits accumulation of proteins in the endoplasmic reticulum, which causes ER overload, resulting in ER stress and cell death either by necrosis or apoptosis. It must be pointed out, however, that this does not necessarily mean that ER stress is the only way that CHX kills L929 fibroblasts, but rather that ER stress is an important target or indicator of cell death induced by this drug.

  17. The unit membrane, the endoplasmic reticulum, and the nuclear pores are artefacts.

    PubMed

    Hillman, H; Sartory, P

    1977-01-01

    It is shown on the basis of solid geometry that the trilaminar appearance of membranes described by Robertson must be an artefact, although the membranes themselves are not. However, considerations of solid geometry as well as observations on living cells indicate that the endoplasmic reticulum and nuclear pores are artefacts resulting from preparation for electron microscopy. Suggestions for their genesis are proposed.

  18. Organization of the cortical endoplasmic reticulum in the squid giant axon.

    PubMed

    Metuzals, J; Chang, D; Hammar, K; Reese, T S

    1997-08-01

    The organization of the cortical endoplasmic reticulum in the squid giant axon was investigated by rapid freeze and freeze-substitution electron microscopy, thereby eliminating the effects of fixatives on this potentially labile structure. Juvenile squid, which have thinner Schwann sheaths, were used in order to achieve freezing deep enough to include the entire axonal cortex. The smooth endoplasmic reticulum is composed of subaxolemmal and deeper cisternae, tubules, tethers and vesicles. The subaxolemmal cisternae make junctional contacts with the axolemma which are characterized by filamentous-granular bridging structures approximately 3 nm in diameter. The subaxolemmal junctions with the axolemma resemble the coupling junctions between the sarcoplasmic reticulum and the T-tubules in muscle. Reconstruction of short series of sections showed that a number of the elements of the endoplasmic reticulum were continuous but numerous separate vesicles were present as well. The morphology of endoplasmic reticulum as described here suggests that it is a highly dynamic entity as well as a Ca2+ sequestering organelle.

  19. Modulation of active Ca2+ uptake by the islet-cell endoplasmic reticulum.

    PubMed Central

    Colca, J R; Kotagal, N; Lacy, P E; McDaniel, M L

    1983-01-01

    The possible effects of calmodulin and cyclic AMP on active Ca2+ uptake by the islet-cell endoplasmic reticulum were investigated. Neither calmodulin nor cyclic AMP affected the rate of active Ca2+ uptake, or the steady-state filling capacity of the endoplasmic reticulum when measured in the absence of oxalate. Consistent with these results, calmodulin did not activate the Ca2+-stimulated ATPase activity associated with this cell fraction. During the course of these experiments., it was unexpectedly discovered that the rate of Ca2+ uptake, as well as the steady-state Ca2+ filling capacity of the endoplasmic reticulum, were markedly increased by unidentified factor(s) in the cytosol. This effect could be demonstrated by reconstitution of the membranes in cytosol, or by direct addition of fresh or dialysed cytosol to the Ca2+ uptake assays. The degree of activation by the cytosol indicates that the endoplasmic reticulum may play a prominent role in controlling beta-cell Ca2+ concentrations and that the unidentified activator(s) present in the cytosol may be involved in regulation of this function. PMID:6307286

  20. Sls1p Stimulates Sec63p-Mediated Activation of Kar2p in a Conformation-Dependent Manner in the Yeast Endoplasmic Reticulum

    PubMed Central

    Kabani, Mehdi; Beckerich, Jean-Marie; Gaillardin, Claude

    2000-01-01

    We previously characterized the SLS1 gene in the yeast Yarrowia lipolytica and showed that it interacts physically with YlKar2p to promote translocation across the endoplasmic-reticulum membrane (A. Boisramé, M. Kabani, J. M. Beckerich, E. Hartmann, and C. Gaillardin, J. Biol. Chem. 273:30903–30908, 1998). A Y. lipolytica Kar2p mutant was isolated that restored interaction with an Sls1p mutant, suggesting that the interaction with Sls1p could be nucleotide and/or conformation dependent. This result was used as a working hypothesis for more accurate investigations in Saccharomyces cerevisiae. We show by two-hybrid an in vitro assays that the S. cerevisiae homologue of Sls1p interacts with ScKar2p. Using dominant lethal mutants of ScKar2p, we were able to show that ScSls1p preferentially interacts with the ADP-bound conformation of the molecular chaperone. Synthetic lethality was observed between ΔScsls1 and translocation-deficient kar2 or sec63-1 mutants, providing in vivo evidence for a role of ScSls1p in protein translocation. Synthetic lethality was also observed with ER-associated degradation and folding-deficient kar2 mutants, strongly suggesting that Sls1p functions are not restricted to the translocation process. We show that Sls1p stimulates in a dose-dependent manner the binding of ScKar2p on the lumenal J domain of Sec63p fused to glutathione S-transferase. Moreover, Sls1p is shown to promote the Sec63p-mediated activation of Kar2p's ATPase activity. Our data strongly suggest that Sls1p could be the first GrpE-like protein described in the endoplasmic reticulum. PMID:10958688

  1. Mitochondrial dysfunction in oocytes of obese mothers: transmission to offspring and reversal by pharmacological endoplasmic reticulum stress inhibitors.

    PubMed

    Wu, Linda L; Russell, Darryl L; Wong, Siew L; Chen, Miaoxin; Tsai, Te-Sha; St John, Justin C; Norman, Robert J; Febbraio, Mark A; Carroll, John; Robker, Rebecca L

    2015-02-15

    Over-nutrition in females causes altered fetal growth during pregnancy and permanently programs the metabolism of offspring; however, the temporal and mechanistic origins of these changes, and whether they are reversible, are unknown. We now show that, in obese female mice, cumulus-oocyte complexes exhibit endoplasmic reticulum (ER) stress, high levels of intracellular lipid, spindle abnormalities and reduced PTX3 extracellular matrix protein production. Ovulated oocytes from obese mice contain normal levels of mitochondrial (mt) DNA but have reduced mitochondrial membrane potential and high levels of autophagy compared with oocytes from lean mice. After in vitro fertilization, the oocytes of obese female mice demonstrate reduced developmental potential and form blastocysts with reduced levels of mtDNA. Blastocysts transferred to normal weight surrogates that were then analyzed at E14.5 showed that oocytes from obese mice gave rise to fetuses that were heavier than controls and had reduced liver and kidney mtDNA content per cell, indicating that maternal obesity before conception had altered the transmission of mitochondria to offspring. Treatment of the obese females with the ER stress inhibitor salubrinal or the chaperone inducer BGP-15 before ovulation increased the amount of the mitochondrial replication factors TFAM and DRP1, and mtDNA content in oocytes. Salubrinal and BGP-15 also completely restored oocyte quality, embryo development and the mtDNA content of fetal tissue to levels equivalent to those derived from lean mice. These results demonstrate that obesity before conception imparts a legacy of mitochondrial loss in offspring that is caused by ER stress and is reversible during the final stages of oocyte development and maturation. PMID:25670793

  2. EBS7 is a plant-specific component of a highly conserved endoplasmic reticulum-associated degradation system in Arabidopsis

    PubMed Central

    Liu, Yidan; Zhang, Congcong; Wang, Dinghe; Su, Wei; Liu, Linchuan; Wang, Muyang; Li, Jianming

    2015-01-01

    Endoplasmic reticulum (ER)-associated degradation (ERAD) is an essential part of an ER-localized protein quality-control system for eliminating terminally misfolded proteins. Recent studies have demonstrated that the ERAD machinery is conserved among yeast, animals, and plants; however, it remains unknown if the plant ERAD system involves plant-specific components. Here we report that the Arabidopsis ethyl methanesulfonate-mutagenized brassinosteroid-insensitive 1 suppressor 7 (EBS7) gene encodes an ER membrane-localized ERAD component that is highly conserved in land plants. Loss-of-function ebs7 mutations prevent ERAD of brassinosteroid insensitive 1-9 (bri1-9) and bri1-5, two ER-retained mutant variants of the cell-surface receptor for brassinosteroids (BRs). As a result, the two mutant receptors accumulate in the ER and consequently leak to the plasma membrane, resulting in the restoration of BR sensitivity and phenotypic suppression of the bri1-9 and bri1-5 mutants. EBS7 accumulates under ER stress, and its mutations lead to hypersensitivity to ER and salt stresses. EBS7 interacts with the ER membrane-anchored ubiquitin ligase Arabidopsis thaliana HMG-CoA reductase degradation 1a (AtHrd1a), one of the central components of the Arabidopsis ERAD machinery, and an ebs7 mutation destabilizes AtHrd1a to reduce polyubiquitination of bri1-9. Taken together, our results uncover a plant-specific component of a plant ERAD pathway and also suggest its likely biochemical function. PMID:26371323

  3. Mitochondrial dysfunction in oocytes of obese mothers: transmission to offspring and reversal by pharmacological endoplasmic reticulum stress inhibitors.

    PubMed

    Wu, Linda L; Russell, Darryl L; Wong, Siew L; Chen, Miaoxin; Tsai, Te-Sha; St John, Justin C; Norman, Robert J; Febbraio, Mark A; Carroll, John; Robker, Rebecca L

    2015-02-15

    Over-nutrition in females causes altered fetal growth during pregnancy and permanently programs the metabolism of offspring; however, the temporal and mechanistic origins of these changes, and whether they are reversible, are unknown. We now show that, in obese female mice, cumulus-oocyte complexes exhibit endoplasmic reticulum (ER) stress, high levels of intracellular lipid, spindle abnormalities and reduced PTX3 extracellular matrix protein production. Ovulated oocytes from obese mice contain normal levels of mitochondrial (mt) DNA but have reduced mitochondrial membrane potential and high levels of autophagy compared with oocytes from lean mice. After in vitro fertilization, the oocytes of obese female mice demonstrate reduced developmental potential and form blastocysts with reduced levels of mtDNA. Blastocysts transferred to normal weight surrogates that were then analyzed at E14.5 showed that oocytes from obese mice gave rise to fetuses that were heavier than controls and had reduced liver and kidney mtDNA content per cell, indicating that maternal obesity before conception had altered the transmission of mitochondria to offspring. Treatment of the obese females with the ER stress inhibitor salubrinal or the chaperone inducer BGP-15 before ovulation increased the amount of the mitochondrial replication factors TFAM and DRP1, and mtDNA content in oocytes. Salubrinal and BGP-15 also completely restored oocyte quality, embryo development and the mtDNA content of fetal tissue to levels equivalent to those derived from lean mice. These results demonstrate that obesity before conception imparts a legacy of mitochondrial loss in offspring that is caused by ER stress and is reversible during the final stages of oocyte development and maturation.

  4. 15 CFR 990.56 - Restoration selection-use of a Regional Restoration Plan or existing restoration project.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Restoration selection-use of a Regional Restoration Plan or existing restoration project. 990.56 Section 990.56 Commerce and Foreign Trade..., DEPARTMENT OF COMMERCE OIL POLLUTION ACT REGULATIONS NATURAL RESOURCE DAMAGE ASSESSMENTS Restoration...

  5. 15 CFR 990.56 - Restoration selection-use of a Regional Restoration Plan or existing restoration project.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Restoration selection-use of a Regional Restoration Plan or existing restoration project. 990.56 Section 990.56 Commerce and Foreign Trade..., DEPARTMENT OF COMMERCE OIL POLLUTION ACT REGULATIONS NATURAL RESOURCE DAMAGE ASSESSMENTS Restoration...

  6. Environmental Restoration Quality Program Plan. Environmental Restoration Program

    SciTech Connect

    Colley, J.S.

    1992-08-01

    The Martin Marietta Energy Systems, Inc., Environmental Restoration (ER) Program was initially chartered on October 1, 1989, as a ``entral Environmental Restoration Division`` to manage the investigation and remediation of inactive sites and facilities that have been declared surplus and have no further programmatic use. The Energy Systems ER Division was established to support the DOE Oak Ridge Field Office (DOE-OR) consolidated ER Program. The DOE-OR Assistant Manager for Environmental Restoration and Waste Management provides program and budget direction to the Energy Systems ER Program for environmental restoration activities at the sites operated by Energy Systems (Oak Ridge K-25 Site, Oak Ridge National Laboratory, Oak Ridge Y-12 Plant, Paducah Gaseous Diffusion Plant, Portsmouth Gaseous Diffusion Plant) and at the off-site locations. The Energy Systems ER Division is specifically charged with assessing these sites for potential contamination and managing the cleanup processes. The Energy Systems Environmental Restoration Division was chartered on October 1, 1989, as a central organization to manage the Remedial Action (RA) Program. The purpose of this document is to ensure that: senior ER management provides planning, organization, direction, control, and support to achieve the organization`s objectives; the line organization achieves quality; and overall performance is reviewed and evaluated using a rigorous assessment process.

  7. [Restoring the occlusion by direct techniques].

    PubMed

    Roeters, F J; Opdam, N M; Stel, M

    2003-06-01

    Today, extensive and generalized tooth wear is often a reason for restoring the occlusion. Adhesive techniques and direct composite restorations can reduce the need for more expensive indirect restorations. In this article the advantages and disadvantages of the direct and indirect techniques are discussed. Furthermore, the treatment sequence for direct restorations is described and illustrated by some case-reports.

  8. 7 CFR 1415.11 - Restoration agreements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Restoration agreements. 1415.11 Section 1415.11... Restoration agreements. (a) Restoration agreements are only authorized to be used in conjunction with... a restoration agreement is needed. Such a determination is also subject to the availability...

  9. 7 CFR 1415.11 - Restoration agreements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Restoration agreements. 1415.11 Section 1415.11... Restoration agreements. (a) Restoration agreements are only authorized to be used in conjunction with... a restoration agreement is needed. Such a determination is also subject to the availability...

  10. A comparison of intrinsic endoplasmic reticulum membrane proteins in maturing seeds and germinated seedlings of castor bean.

    PubMed

    Goldberg, D B; Al-Marayati, S; González, E

    1982-01-01

    The intrinsic membrane proteins of the endoplasmic reticulum from endosperm of maturing and germinated seedlings of castor bean (Ricinus communis) were studied. Preparations were simultaneously subjected to two-dimensional polyacrylamide gel electrophoresis. At least 30 separate proteins were distinguished by staining the gels with Coomassie R-250. The characteristic protein profiles obtained from 0.2 m KCl-washed membranes of each endoplasmic reticulum source are highly reproducible. Of these proteins, three to six that were present in maturing seed were found also in germinating seedlings. In general, the majority of membrane proteins from the endoplasmic reticulum of maturing seed were of a higher molecular weight than those from germinated seedlings.

  11. Environmental Restoration Quality Program Plan

    SciTech Connect

    Colley, J.S.

    1992-08-01

    The Martin Marietta Energy Systems, Inc., Environmental Restoration (ER) Program was initially chartered on October 1, 1989, as a entral Environmental Restoration Division'' to manage the investigation and remediation of inactive sites and facilities that have been declared surplus and have no further programmatic use. The Energy Systems ER Division was established to support the DOE Oak Ridge Field Office (DOE-OR) consolidated ER Program. The DOE-OR Assistant Manager for Environmental Restoration and Waste Management provides program and budget direction to the Energy Systems ER Program for environmental restoration activities at the sites operated by Energy Systems (Oak Ridge K-25 Site, Oak Ridge National Laboratory, Oak Ridge Y-12 Plant, Paducah Gaseous Diffusion Plant, Portsmouth Gaseous Diffusion Plant) and at the off-site locations. The Energy Systems ER Division is specifically charged with assessing these sites for potential contamination and managing the cleanup processes. The Energy Systems Environmental Restoration Division was chartered on October 1, 1989, as a central organization to manage the Remedial Action (RA) Program. The purpose of this document is to ensure that: senior ER management provides planning, organization, direction, control, and support to achieve the organization's objectives; the line organization achieves quality; and overall performance is reviewed and evaluated using a rigorous assessment process.

  12. Sound Strategies for Hearing Restoration

    PubMed Central

    Géléoc, Gwenaëlle S.G.; Holt, Jeffrey R.

    2014-01-01

    Hearing loss is the most common sensory deficit in humans with some estimates suggesting up to 300 million affected individuals worldwide. Both environmental and genetic factors contribute to hearing loss and can cause death of sensory cells and neurons. Since these cells do not regenerate, the damage tends to accumulate leading to profound deafness. Several biological strategies to restore auditory function are currently under investigation. Due to the success of cochlear implants, which offer partial recovery of auditory function for some profoundly deaf patients, potential biological therapies must extend hearing restoration to include greater auditory acuity and larger patient populations. Here we review the latest gene, stem-cell, and molecular strategies for restoring auditory function in animal models and the prospects for translating these approaches into viable clinical therapies. PMID:24812404

  13. Sound strategies for hearing restoration.

    PubMed

    Géléoc, Gwenaëlle S G; Holt, Jeffrey R

    2014-05-01

    Hearing loss is the most common sensory deficit in humans, with some estimates suggesting up to 300 million affected individuals worldwide. Both environmental and genetic factors contribute to hearing loss and can cause death of sensory cells and neurons. Because these cells do not regenerate, the damage tends to accumulate, leading to profound deafness. Several biological strategies to restore auditory function are currently under investigation. Owing to the success of cochlear implants, which offer partial recovery of auditory function for some profoundly deaf patients, potential biological therapies must extend hearing restoration to include greater auditory acuity and larger patient populations. Here, we review the latest gene, stem-cell, and molecular strategies for restoring auditory function in animal models and the prospects for translating these approaches into viable clinical therapies. PMID:24812404

  14. Conservative preparations for cast restorations.

    PubMed

    Shillingburg, H T

    1976-04-01

    Partial veneer crowns still play a role in modern restorative dentistry. They must be used in the right situation with thoughtful treatment planning, and they must be done well in accordance with certain principles. Three-quarter crowns are less retentive than full crowns, but they can be used successfully as single unit restorations and retainers for short span bridges. Retention can be enhanced by the use of proximal boxes. The M.O.D. onlay, a modified inlay with occlusal coverage, minimizes the damaging effects of stress generated by occlusal forces. There is little indication for the use of M.O.D. inlays or large two surface inlays.

  15. Treatment planning for restorative implantology.

    PubMed

    Boyce, Ricardo A; Klemons, Gary

    2015-04-01

    In this article, current literature on fixed and removable prosthodontics is reviewed along with evidence-based systematic reviews, including advice from those in the dental profession with years of experience, which help restorative dentists manage and treat their cases successfully. Treatment planning for restorative implantology should be looked at in 4 sections: (1) review of past medical history, (2) oral examination and occlusion, (3) dental imaging (ie, cone-beam computed tomography), and (4) fixed versus removable prosthodontics. These 4 concepts of treatment planning, along with proper surgical placements of the implant(s), result in successful cases. PMID:25835794

  16. Call to Restore Mesopotamian Marshlands

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    Call to restore Mesopotamian marshlands When the current military conflict in Iraq has concluded, a rehabilitation of that country should include a full assessment and action plan for restoring the marshlands of Mesopotamia, the United Nations Environment Programme said on 22 March. The marshlands, also known as the Fertile Crescent, could disappear within three to five years, according to UNEP. UNEP Executive Director Klaus Toepfer said the loss of the marshlands ``is an environmental catastrophe for this region and underscores the huge pressures facing wetlands and freshwater ecosystems across the world.''

  17. Tongue piercing: a restorative perspective.

    PubMed

    Bassiouny, M A; Deem, L P; Deem, T E

    2001-06-01

    The implication of a traumatic injury to a permanent molar tooth as a complication by tongue piercing with ornamental jewelry is reported. An appropriate restorative management of the fractured tooth is described. The dentist's role in prevention and treatment of unfavorable complications is outlined. The rationales for selection of specific treatment modalities, in view of the degree of damage to hard dental tissues, are discussed. The range of hard tissue injuries resulting from tongue jewelry varies from a simple crack propagating into the enamel to a fractured tooth. A variety of factors must be considered before employing the available restorative methods. PMID:11491628

  18. Restoring Detroit's Street Lighting System

    SciTech Connect

    Kinzey, Bruce R.

    2015-10-21

    The City of Detroit is undertaking a comprehensive restoration of its street lighting system that includes transitioning the existing high-pressure sodium (HPS) sources to light-emitting diode (LED). Detroit’s well-publicized financial troubles over the last several years have added many hurdles and constraints to this process. Strategies to overcome these issues have largely been successful, but have also brought some mixed results. This document provides an objective review of the circumstances surrounding the system restoration, the processes undertaken and decisions made, and the results so far.

  19. Treatment planning for restorative implantology.

    PubMed

    Boyce, Ricardo A; Klemons, Gary

    2015-04-01

    In this article, current literature on fixed and removable prosthodontics is reviewed along with evidence-based systematic reviews, including advice from those in the dental profession with years of experience, which help restorative dentists manage and treat their cases successfully. Treatment planning for restorative implantology should be looked at in 4 sections: (1) review of past medical history, (2) oral examination and occlusion, (3) dental imaging (ie, cone-beam computed tomography), and (4) fixed versus removable prosthodontics. These 4 concepts of treatment planning, along with proper surgical placements of the implant(s), result in successful cases.

  20. Modeling of toxin-antibody interaction and toxin transport toward the endoplasmic reticulum.

    PubMed

    Skakauskas, Vladas; Katauskis, Pranas

    2016-01-01

    A model for toxin-antibody interaction and toxin trafficking towards the endoplasmic-reticulum is presented. Antibody and toxin (ricin) initially are delivered outside the cell. The model involves: the pinocytotic (cellular drinking) and receptor-mediated toxin internalization modes from the extracellular into the intracellular domain, its exocytotic excretion from the cytosol back to the extracellular medium, the intact toxin retrograde transport to the endoplasmic reticulum, the anterograde toxin movement outward from the cell across the plasma membrane, the lysosomal toxin degradation, and the toxin clearance (removal from the system) flux. The model consists of a set of coupled PDEs. Using an averaging procedure, the model is reduced to a system of coupled ODEs. Both PDEs and ODEs systems are solved numerically. Numerical results are illustrated by figures and discussed.

  1. Protein accumulation in the endoplasmic reticulum as a non-equilibrium phase transition.

    PubMed

    Budrikis, Zoe; Costantini, Giulio; La Porta, Caterina A M; Zapperi, Stefano

    2014-01-01

    Several neurological disorders are associated with the aggregation of aberrant proteins, often localized in intracellular organelles such as the endoplasmic reticulum. Here we study protein aggregation kinetics by mean-field reactions and three dimensional Monte carlo simulations of diffusion-limited aggregation of linear polymers in a confined space, representing the endoplasmic reticulum. By tuning the rates of protein production and degradation, we show that the system undergoes a non-equilibrium phase transition from a physiological phase with little or no polymer accumulation to a pathological phase characterized by persistent polymerization. A combination of external factors accumulating during the lifetime of a patient can thus slightly modify the phase transition control parameters, tipping the balance from a long symptomless lag phase to an accelerated pathological development. The model can be successfully used to interpret experimental data on amyloid-β clearance from the central nervous system. PMID:24722051

  2. Protein accumulation in the endoplasmic reticulum as a non-equilibrium phase transition

    PubMed Central

    Budrikis, Zoe; Costantini, Giulio; La Porta, Caterina A. M.; Zapperi, Stefano

    2014-01-01

    Several neurological disorders are associated with the aggregation of aberrant proteins, often localized in intracellular organelles such as the endoplasmic reticulum. Here we study protein aggregation kinetics by mean-field reactions and three dimensional Monte carlo simulations of diffusion-limited aggregation of linear polymers in a confined space, representing the endoplasmic reticulum. By tuning the rates of protein production and degradation, we show that the system undergoes a non-equilibrium phase transition from a physiological phase with little or no polymer accumulation to a pathological phase characterized by persistent polymerization. A combination of external factors accumulating during the lifetime of a patient can thus slightly modify the phase transition control parameters, tipping the balance from a long symptomless lag phase to an accelerated pathological development. The model can be successfully used to interpret experimental data on amyloid-β clearance from the central nervous system. PMID:24722051

  3. Transport of cholesterol from the endoplasmic reticulum to the plasma membrane

    PubMed Central

    1985-01-01

    We have studied the transport of newly synthesized cholesterol from the endoplasmic reticulum to the plasma membrane in Chinese hamster ovary cells using a cell fractionation assay. We found that transport is dependent on metabolic energy, but that the maintenance of the high differential concentration of cholesterol in the plasma membrane is not an energy-requiring process. We have tested a variety of inhibitors for their effect on cholesterol transport and found that cytochalasin B, colchicine, monensin, cycloheximide, and NH4Cl did not have any effect. The cholesterol transport process shows a sharp temperature dependence; it ceases at 15 degrees C, whereas cholesterol synthesis continues. When synthesis occurs at 15 degrees C, the newly synthesized cholesterol accumulates in the endoplasmic reticulum and in a low density, lipid-rich vesicle fraction. These results suggest that cholesterol is transported via a vesicular system. PMID:4040520

  4. Titanium Dioxide Nanoparticles Induce Endoplasmic Reticulum Stress-Mediated Autophagic Cell Death via Mitochondria-Associated Endoplasmic Reticulum Membrane Disruption in Normal Lung Cells.

    PubMed

    Yu, Kyeong-Nam; Chang, Seung-Hee; Park, Soo Jin; Lim, Joohyun; Lee, Jinkyu; Yoon, Tae-Jong; Kim, Jun-Sung; Cho, Myung-Haing

    2015-01-01

    Nanomaterials are used in diverse fields including food, cosmetic, and medical industries. Titanium dioxide nanoparticles (TiO2-NP) are widely used, but their effects on biological systems and mechanism of toxicity have not been elucidated fully. Here, we report the toxicological mechanism of TiO2-NP in cell organelles. Human bronchial epithelial cells (16HBE14o-) were exposed to 50 and 100 μg/mL TiO2-NP for 24 and 48 h. Our results showed that TiO2-NP induced endoplasmic reticulum (ER) stress in the cells and disrupted the mitochondria-associated endoplasmic reticulum membranes (MAMs) and calcium ion balance, thereby increasing autophagy. In contrast, an inhibitor of ER stress, tauroursodeoxycholic acid (TUDCA), mitigated the cellular toxic response, suggesting that TiO2-NP promoted toxicity via ER stress. This novel mechanism of TiO2-NP toxicity in human bronchial epithelial cells suggests that further exhaustive research on the harmful effects of these nanoparticles in relevant organisms is needed for their safe application. PMID:26121477

  5. Service Lives Of Restored Bearings

    NASA Technical Reports Server (NTRS)

    Zaretsky, Erwin V.

    1988-01-01

    Rebuilt units last almost as long as new ones. Report describes theoretical and experiemental studies of lifetimes of restored ball and cylindrical-roller bearings. Results of this and related studies have implications of economy and safety in modern high-speed machinery, especially in aircraft industry, where inspection and rejection or replacing of bearings are new standard practice.

  6. Weed biocontrol in landscape restoration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed biological control programs in natural areas are often undertaken with the goal of restoring native plant communities and/or ecosystem services to a pre-invasion level. These objectives may be achieved in some areas with biological control alone; however, in other sites integration of biologica...

  7. Speech Restoration: An Interactive Process

    ERIC Educational Resources Information Center

    Grataloup, Claire; Hoen, Michael; Veuillet, Evelyne; Collet, Lionel; Pellegrino, Francois; Meunier, Fanny

    2009-01-01

    Purpose: This study investigates the ability to understand degraded speech signals and explores the correlation between this capacity and the functional characteristics of the peripheral auditory system. Method: The authors evaluated the capability of 50 normal-hearing native French speakers to restore time-reversed speech. The task required them…

  8. Natural look in volume restoration.

    PubMed

    Lupo, Mary P

    2008-09-01

    Filling and volumizing injection procedures are currently widely used for facial augmentation and re-establishing a youthful appearance. Aesthetic physicians have advanced from the practice of treating single lines and wrinkles towards filling large facial areas to globally restore natural facial contours and meet patient demand for nonsurgical rejuvenation. This review describes the different categories of fillers and volumizers based on their duration of action and ability to create a natural looking effect; they can be broadly classified as temporary or long-lasting biodegradable agents, or permanent nonbiodegradable agents. Temporary fillers are effective to correct lines and wrinkles, but may not adequately meet the need for global facial rejuvenation and volume replacement in a long-term, cost-efficient manner. Permanent fillers for global restoration pose the issue of long-term safety, and may not be compatible with changes in facial architecture with continued aging. Longer lasting volumizers provide patients with a durable, effective option for the restoration of facial volume and the re-establishment of youthful facial contours. Temporary fillers and volumizers may also be used in combination to provide a wide source of options for the global restoration and rejuvenation of the face.

  9. Origins of the Restoration Playhouse.

    ERIC Educational Resources Information Center

    Wilson, Dennis D.

    Contrary to the popular theory that the proscenium type of playhouse was imported from France by the Court of Charles II in 1660, the Restoration playhouse in fact developed from Elizabethan theatres and court masques. These Elizabethan theatres were the private theatres, and were generally small, rectangular, roofed structures where aristocratic…

  10. The restorative management of microdontia.

    PubMed

    Laverty, D P; Thomas, M B M

    2016-08-26

    Microdontia is a dental abnormality that will often present to the dental practitioner due to the aesthetic concerns of the patient. Treatment is therefore aimed at addressing the aesthetics issue of the patient and this can present a number of challenges which may require a multidisciplinary approach in its management. This article presents the restorative management of localised and generalised microdontia. PMID:27561572

  11. Recent advances in hearing restoration.

    PubMed

    Kulkarni, Kunal; Hartley, Douglas Eh

    2008-03-01

    This review is based on Pubmed, Medline and Internet literature searches, supplemented by knowledge from textbooks, conference presentations, and personal communications with experts in the field of hearing restoration and patients. We have not specifically selected a time limit for our literature searches; however, the majority are articles from the past 5 years. PMID:18344468

  12. Restored Behavior and Oral Traditions.

    ERIC Educational Resources Information Center

    Miranda, Kathleen Bindert

    Interest in oral traditions has benefitted the field of interpretation in two ways: a new emphasis on the social and cultural contexts of performance, and an expanded perspective on performance manifestations. In Richard Schechner's concept of "restored behavior," the interpreter engages in a reconstruction of living behavior independent of its…

  13. Conceptualizing and Communicating River Restoration

    NASA Astrophysics Data System (ADS)

    Jacobosn, R. B.

    2007-12-01

    River restoration increasingly involves collaboration with stakeholders having diverse values and varying technical understanding. In cases where river restoration proceeds through collaborative processes, scientists are required to communicate complex understanding about riverine ecosystem processes to broad audiences. Of particular importance is communication of uncertainties in predictions of ecosystem responses to restoration actions, and how those uncertainties affect monitoring and evaluation strategies. I present a relatively simple conceptual model of how riverine ecosystems operate. The model, which has been used to conceptualize and communicate various river-restoration and management processes in the Lower Missouri River, emphasizes a) the interdependencies of driving regimes (for example, flow, sediment, and water quality), b) the filtering effect of management history, c) the typical hierarchical nature of information about how ecosystems operate, and d) how scientific understanding interacts with decision making. I provide an example of how the conceptual model has been used to illustrate the effects of extensive channel re-engineering of the Lower Missouri River which is intended to mitigate the effects of channelization and flow regulation on aquatic and flood-plain ecosystems. The conceptual model illustrates the logic for prioritizing investments in monitoring and evaluation, interactions among ecosystem components, tradeoffs between ecological and social-commercial benefits, and the feedback loop necessary for successful adaptive management.

  14. The endoplasmic reticulum as a potential therapeutic target in nonalcoholic fatty liver disease

    PubMed Central

    Gentile, Christopher L; Pagliassotti, Michael J

    2008-01-01

    The endoplasmic reticulum (ER) has emerged as a key to understanding the development and consequences of hepatic fat accumulation in nonalcoholic fatty liver disease (NAFLD). An essential function of this organelle is the proper assembly of proteins that are destined for intracellular organelles and the cell surface. Recent evidence suggests that chemical chaperones that enhance the functional capacity of the ER improve liver function in obesity and NAFLD. These chaperones may therefore provide a novel potential therapeutic strategy in NAFLD. PMID:18821470

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

    PubMed Central

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

    2016-01-01

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

  16. Cholesterol and steroid synthesizing smooth endoplasmic reticulum of adrenocortical cells contains high levels of proteins associated with the translocation channel.

    PubMed

    Black, Virginia H; Sanjay, Archana; van Leyen, Klaus; Lauring, Brett; Kreibich, Gert

    2005-10-01

    Steroid-secreting cells are characterized by abundant smooth endoplasmic reticulum whose membranes contain many enzymes involved in sterol and steroid synthesis. Yet they have relatively little morphologically identifiable rough endoplasmic reticulum, presumably required for synthesis and maintenance of the smooth membranes. In this study, we demonstrate that adrenal smooth microsomal subfractions enriched in smooth endoplasmic reticulum membranes contain high levels of translocation apparatus and oligosaccharyltransferase complex proteins, previously thought confined to rough endoplasmic reticulum. We further demonstrate that these smooth microsomal subfractions are capable of effecting cotranslational translocation, signal peptide cleavage, and N-glycosylation of newly synthesized polypeptides. This shifts the paradigm for distinction between smooth and rough endoplasmic reticulum. Confocal microscopy revealed the proteins to be distributed throughout the abundant tubular endoplasmic reticulum in these cells, which is predominantly smooth surfaced. We hypothesize that the broadly distributed translocon and oligosaccharyltransferase proteins participate in local synthesis and/or quality control of membrane proteins involved in cholesterol and steroid metabolism in a sterol-dependent and hormonally regulated manner.

  17. Cytoplasmic nucleation and atypical branching nucleation generate endoplasmic microtubules in Physcomitrella patens.

    PubMed

    Nakaoka, Yuki; Kimura, Akatsuki; Tani, Tomomi; Goshima, Gohta

    2015-01-01

    The mechanism underlying microtubule (MT) generation in plants has been primarily studied using the cortical MT array, in which fixed-angled branching nucleation and katanin-dependent MT severing predominate. However, little is known about MT generation in the endoplasm. Here, we explored the mechanism of endoplasmic MT generation in protonemal cells of Physcomitrella patens. We developed an assay that utilizes flow cell and oblique illumination fluorescence microscopy, which allowed visualization and quantification of individual MT dynamics. MT severing was infrequently observed, and disruption of katanin did not severely affect MT generation. Branching nucleation was observed, but it showed markedly variable branch angles and was occasionally accompanied by the transport of nucleated MTs. Cytoplasmic nucleation at seemingly random locations was most frequently observed and predominated when depolymerized MTs were regrown. The MT nucleator γ-tubulin was detected at the majority of the nucleation sites, at which a single MT was generated in random directions. When γ-tubulin was knocked down, MT generation was significantly delayed in the regrowth assay. However, nucleation occurred at a normal frequency in steady state, suggesting the presence of a γ-tubulin-independent backup mechanism. Thus, endoplasmic MTs in this cell type are generated in a less ordered manner, showing a broader spectrum of nucleation mechanisms in plants.

  18. Technology needs for environmental restoration remedial action. Environmental Restoration Program

    SciTech Connect

    Watson, J.S.

    1992-11-01

    This report summarizes the current view of the most important technology needs for the US Department of Energy (DOE) facilities operated by Martin Marietta Energy Systems, Inc. These facilities are the Oak Ridge National Laboratory, the Oak Ridge K-25 Site, the Oak Ridge Y-12 Plant, the Paducah Gaseous Diffusion Plant, and the Portsmouth Gaseous Diffusion Plant. The sources of information used in this assessment were a survey of selected representatives of the Environmental Restoration (ER) programs at each facility, results from a questionnaire distributed by Geotech CWM, Inc., for DOE, and associated discussions with individuals from each facility. This is not a final assessment, but a brief look at an ongoing assessment; the needs will change as the plans for restoration change and, it is hoped, as some technical problems are solved through successful development programs.

  19. A LAPF/phafin1-like protein regulates TORC1 and lysosomal membrane permeabilization in response to endoplasmic reticulum membrane stress

    PubMed Central

    Kim, Adam; Cunningham, Kyle W.

    2015-01-01

    Lysosomal membrane permeabilization (LMP) is a poorly understood regulator of programmed cell death that involves leakage of luminal lysosomal or vacuolar hydrolases into the cytoplasm. In Saccharomyces cerevisiae, LMP can be induced by antifungals and endoplasmic reticulum stressors when calcineurin also has been inactivated. A genome-wide screen revealed Pib2, a relative of LAPF/phafin1 that regulates LMP in mammals, as a pro-LMP protein in yeast. Pib2 associated with vacuolar and endosomal limiting membranes in unstressed cells in a manner that depended on its FYVE domain and on phosphatidylinositol 3-phosphate (PI(3)P) biosynthesis. Genetic experiments suggest that Pib2 stimulates the activity of TORC1, a vacuole-associated protein kinase that is sensitive to rapamycin, in a pathway parallel to the Ragulator/EGO complex containing the GTPases Gtr1 and Gtr2. A hyperactivating mutation in the catalytic subunit of TORC1 restored LMP to the gtr1∆ and pib2∆ mutants and also prevented the synthetic lethality of the double mutants. These findings show novel roles of PI(3)P and Pib2 in the regulation of TORC1, which in turn promoted LMP and nonapoptotic death of stressed cells. Rapamycin prevented the death of the pathogenic yeast Candida albicans during exposure to fluconazole plus a calcineurin inhibitor, suggesting that TORC1 broadly promotes sensitivity to fungistats in yeasts. PMID:26510498

  20. Alpha-lipoic acid attenuates endoplasmic reticulum stress-induced insulin resistance by improving mitochondrial function in HepG2 cells.

    PubMed

    Lei, Lin; Zhu, Yiwei; Gao, Wenwen; Du, Xiliang; Zhang, Min; Peng, Zhicheng; Fu, Shoupeng; Li, Xiaobing; Zhe, Wang; Li, Xinwei; Liu, Guowen

    2016-10-01

    Alpha-lipoic acid (ALA) has been reported to have beneficial effects for improving insulin sensitivity. However, the underlying molecular mechanism of the beneficial effects remains poorly understood. Endoplasmic reticulum (ER) stress and mitochondrial dysfunction are considered causal factors that induce insulin resistance. In this study, we investigated the effect of ALA on the modulation of insulin resistance in ER-stressed HepG2 cells, and we explored the potential mechanism of this effect. HepG2 cells were incubated with tunicamycin (Tun) for 6h to establish an ER stress cell model. Tun treatment induced ER stress, mitochondrial dysfunction and insulin resistance. Interestingly, ALA had no significant effect on ER stress signals. Pretreatment of the ER stress cell model with ALA for 24h improved insulin sensitivity, restored the expression levels of mitochondrial oxidative phosphorylation (OXPHOS) complexes and increased intracellular ATP production. Moreover, ALA augmented the β-oxidation capacity of the mitochondria. Importantly, ALA treatment could decrease oligomycin-induced mitochondrial dysfunction and then improved insulin resistance. Taken together, our data suggest that ALA prevents ER stress-induced insulin resistance by enhancing mitochondrial function.

  1. A novel role for epidermal growth factor receptor tyrosine kinase and its downstream endoplasmic reticulum stress in cardiac damage and microvascular dysfunction in type 1 diabetes mellitus.

    PubMed

    Galán, Maria; Kassan, Modar; Choi, Soo-Kyoung; Partyka, Megan; Trebak, Mohamed; Henrion, Daniel; Matrougui, Khalid

    2012-07-01

    Epidermal growth factor receptor tyrosine kinase (EGFRtk) and endoplasmic reticulum (ER) stress are important factors in cardiovascular complications. Understanding whether enhanced EGFRtk activity and ER stress induction are involved in cardiac damage, and microvascular dysfunction in type 1 diabetes mellitus is an important question that has remained unanswered. Cardiac fibrosis and microvascular function were determined in C57BL/6J mice injected with streptozotocin only or in combination with EGFRtk inhibitor (AG1478), ER stress inhibitor (Tudca), or insulin for 2 weeks. In diabetic mice, we observed an increase in EGFRtk phosphorylation and ER stress marker expression (CHOP, ATF4, ATF6, and phosphorylated-eIF2α) in heart and mesenteric resistance arteries, which were reduced with AG1478, Tudca, and insulin. Cardiac fibrosis, enhanced collagen type I, and plasminogen activator inhibitor 1 were decreased with AG1478, Tudca, and insulin treatments. The impaired endothelium-dependent relaxation and -independent relaxation responses were also restored after treatments. The inhibition of NO synthesis reduced endothelium-dependent relaxation in control and treated streptozotocin mice, whereas the inhibition of NADPH oxidase improved endothelium-dependent relaxation only in streptozotocin mice. Moreover, in mesenteric resistance arteries, the mRNA levels of Nox2 and Nox4 and the NADPH oxidase activity were augmented in streptozotocin mice and reduced with treatments. This study unveiled novel roles for enhanced EGFRtk phosphorylation and its downstream ER stress in cardiac fibrosis and microvascular endothelial dysfunction in type 1 diabetes mellitus.

  2. Role of ERO1-alpha-mediated stimulation of inositol 1,4,5-triphosphate receptor activity in endoplasmic reticulum stress-induced apoptosis.

    PubMed

    Li, Gang; Mongillo, Marco; Chin, King-Tung; Harding, Heather; Ron, David; Marks, Andrew R; Tabas, Ira

    2009-09-21

    Endoplasmic reticulum (ER) stress-induced apoptosis is involved in many diseases, but the mechanisms linking ER stress to apoptosis are incompletely understood. Based on roles for C/EPB homologous protein (CHOP) and ER calcium release in apoptosis, we hypothesized that apoptosis involves the activation of inositol 1,4,5-triphosphate (IP3) receptor (IP3R) via CHOP-induced ERO1-alpha (ER oxidase 1 alpha). In ER-stressed cells, ERO1-alpha is induced by CHOP, and small interfering RNA (siRNA) knockdown of ERO1-alpha suppresses apoptosis. IP3-induced calcium release (IICR) is increased during ER stress, and this response is blocked by siRNA-mediated silencing of ERO1-alpha or IP3R1 and by loss-of-function mutations in Ero1a or Chop. Reconstitution of ERO1-alpha in Chop(-/-) macrophages restores ER stress-induced IICR and apoptosis. In vivo, macrophages from wild-type mice but not Chop(-/-) mice have elevated IICR when the animals are challenged with the ER stressor tunicamycin. Macrophages from insulin-resistant ob/ob mice, another model of ER stress, also have elevated IICR. These data shed new light on how the CHOP pathway of apoptosis triggers calcium-dependent apoptosis through an ERO1-alpha-IP3R pathway.

  3. Endoplasmic reticulum stress and the unfolded protein response are linked to synergistic IFN-beta induction via X-box binding protein 1.

    PubMed

    Smith, Judith A; Turner, Matthew J; DeLay, Monica L; Klenk, Erin I; Sowders, Dawn P; Colbert, Robert A

    2008-05-01

    Type I IFN are strongly induced upon engagement of certain pattern recognition receptors by microbial products, and play key roles in regulating innate and adaptive immunity. It has become apparent that the endoplasmic reticulum (ER) stress-induced unfolded protein response (UPR), in addition to restoring ER homeostasis, also influences the expression of certain inflammatory cytokines. However, the extent to which UPR signaling regulates type I IFN remains unclear. Here we show that cells undergoing a UPR respond to TLR4 and TLR3 ligands, and intracellular dsRNA, with log-fold greater IFN-beta induction. This synergy is not dependent on autocrine type I IFN signaling, but unexpectedly requires the UPR transcription factor X-box binding protein 1 (XBP-1). Synergistic IFN-beta induction also occurs in HLA-B27/human beta(2)m-transgenic rat macrophages exhibiting a UPR as a consequence of HLA-B27 up-regulation, where it correlates with activation of XBP-1 splicing. Together these findings indicate that the cellular response to endogenous 'danger' that disrupts ER homeostasis is coupled to IFN-beta induction by XBP-1, which has implications for the immune response and the pathogenesis of diseases involving the UPR.

  4. Cross-talk between endoplasmic reticulum (ER) stress and the MEK/ERK pathway potentiates apoptosis in human triple negative breast carcinoma cells: role of a dihydropyrimidone, nifetepimine.

    PubMed

    Ghosh, Swatilekha; Adhikary, Arghya; Chakraborty, Supriya; Bhattacharjee, Pushpak; Mazumder, Minakshi; Putatunda, Salil; Gorain, Mahadeo; Chakraborty, Arijit; Kundu, Gopal C; Das, Tanya; Sen, Parimal C

    2015-02-13

    Triple negative breast cancers (TNBC) are among the most aggressive and therapy-resistant breast tumors and currently possess almost no molecular targets for therapeutic options in this horizon. In the present study we discerned the molecular mechanisms of potential interaction between the endoplasmic reticulum (ER) stress response and the MEK/ERK pathway in inducing apoptosis in TNBC cells. Here we observed that induction of ER stress alone was not sufficient to trigger significant apoptosis but simultaneous inhibition of the MEK/ERK pathway enhanced ER stress-induced apoptosis via a caspase-dependent mechanism. Our study also demonstrated nifetepimine, a dihydropyrimidone derivative as a potent anti-cancer agent in TNBC cells. Nifetepimine down-regulated the MEK/ERK pathway in MDAMB-231 and MDAMB-468 cells and resulted in blockage of ER stress-mediated GRP78 up-regulation. Detailed mechanistic studies also revealed that nifetepimine by down-regulating pERK expression also declined the promoter binding activity of TFII-I to the GRP78 promoter and in turn regulated GRP78 transcription. Studies further extended to in vivo Swiss albino and SCID mice models also revalidated the anti-carcinogenic property of nifetepimine. Thus our findings cumulatively suggest that nifetepimine couples two distinct signaling pathways to induce the apoptotic death cascade in TNBC cells and raises the possibility for the use of nifetepimine as a potent anti-cancer agent with strong immune-restoring properties for therapeutic intervention for this group of cancer bearers.

  5. Exxon Valdez oil spill restoration plan

    SciTech Connect

    1994-11-01

    In 1989, the Exxon Valdez oil spill contaminated about 1,500 miles of Alaska`s coastline. It killed birds, mammals, and fish, and disrupted the ecosystem in the path of the oil. The Exxon Valdez Restoration Plan provides long-term guidance for restoring the resources and services injured by the oil spill. It contains policies for making restoration decisions and describes how restoration activities will be implemented.

  6. 7 CFR 3201.77 - Asphalt restorers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Asphalt restorers. 3201.77 Section 3201.77... Designated Items § 3201.77 Asphalt restorers. (a) Definition. Products designed to seal, protect, or restore poured asphalt and concrete surfaces. (b) Minimum biobased content. The Federal preferred...

  7. 7 CFR 3201.77 - Asphalt restorers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Asphalt restorers. 3201.77 Section 3201.77... Designated Items § 3201.77 Asphalt restorers. (a) Definition. Products designed to seal, protect, or restore poured asphalt and concrete surfaces. (b) Minimum biobased content. The Federal preferred...

  8. 20 CFR 228.52 - Restored amount.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Restored amount. 228.52 Section 228.52... SURVIVOR ANNUITIES The Tier II Annuity Component § 228.52 Restored amount. (a) General. A restored amount...(er) had ten years of creditable railroad service prior to January 1, 1975. (b) Amount. The amount...

  9. 20 CFR 228.52 - Restored amount.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Restored amount. 228.52 Section 228.52... SURVIVOR ANNUITIES The Tier II Annuity Component § 228.52 Restored amount. (a) General. A restored amount...(er) had ten years of creditable railroad service prior to January 1, 1975. (b) Amount. The amount...

  10. 36 CFR 910.65 - Restoration.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... DEVELOPMENT AREA Glossary of Terms § 910.65 Restoration. Restoration means the process of accurately... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Restoration. 910.65 Section 910.65 Parks, Forests, and Public Property PENNSYLVANIA AVENUE DEVELOPMENT CORPORATION...

  11. RESEARCH NEEDS IN RIPARIAN BUFFER RESTORATION

    EPA Science Inventory

    Riparian buffer restorations are used as management tools to produce favorable water quality impacts; moreover, the basis for riparian buffers as an instrument of water quality restoration rests on a relatively firm foundation. However, the extent to which buffers can restore rip...

  12. 15 CFR 990.26 - Emergency restoration.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Emergency restoration. 990.26 Section... NATURAL RESOURCE DAMAGE ASSESSMENTS Authorities § 990.26 Emergency restoration. (a) Trustees may take emergency restoration action before completing the process established under this part, provided that:...

  13. 5 CFR 353.301 - Restoration rights.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Restoration rights. 353.301 Section 353.301 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS RESTORATION TO DUTY FROM UNIFORMED SERVICE OR COMPENSABLE INJURY Compensable Injury § 353.301 Restoration rights....

  14. 43 CFR 11.21 - Emergency restorations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Emergency restorations. 11.21 Section 11... Preassessment Phase § 11.21 Emergency restorations. (a) Reporting requirements and definition. (1) In the event... limited off-site restoration action consistent with its existing authority to the extent necessary...

  15. 36 CFR 910.65 - Restoration.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Restoration. 910.65 Section 910.65 Parks, Forests, and Public Property PENNSYLVANIA AVENUE DEVELOPMENT CORPORATION GENERAL... DEVELOPMENT AREA Glossary of Terms § 910.65 Restoration. Restoration means the process of...

  16. 5 CFR 353.301 - Restoration rights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Restoration rights. 353.301 Section 353.301 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS RESTORATION TO DUTY FROM UNIFORMED SERVICE OR COMPENSABLE INJURY Compensable Injury § 353.301 Restoration rights....

  17. 43 CFR 11.21 - Emergency restorations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Emergency restorations. 11.21 Section 11... Preassessment Phase § 11.21 Emergency restorations. (a) Reporting requirements and definition. (1) In the event... limited off-site restoration action consistent with its existing authority to the extent necessary...

  18. 15 CFR 990.26 - Emergency restoration.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Emergency restoration. 990.26 Section... NATURAL RESOURCE DAMAGE ASSESSMENTS Authorities § 990.26 Emergency restoration. (a) Trustees may take emergency restoration action before completing the process established under this part, provided that:...

  19. 36 CFR 910.65 - Restoration.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Restoration. 910.65 Section 910.65 Parks, Forests, and Public Property PENNSYLVANIA AVENUE DEVELOPMENT CORPORATION GENERAL... DEVELOPMENT AREA Glossary of Terms § 910.65 Restoration. Restoration means the process of...

  20. Optimum constrained image restoration filters

    NASA Technical Reports Server (NTRS)

    Riemer, T. E.; Mcgillem, C. D.

    1977-01-01

    The research described centered on development of an optimum image restoration filter (IRF) minimizing the radius of gyration of the corrected or composite system point-spread function (P-SF) subject to contraints, and reducing 2-dimensional spatial smearing or blurring of an image. The constraints are imposed on the radius of gyration of the IRF P-SF, the total restored image noise power, and the shape of the composite system frequency spectrum. The image degradation corresponds to mapping many points from the original image into a single resolution element. The P-SF is obtained as solution to a set of simultaneous differential equations obeying nonlinear integral constraints. Truncation errors due to edge effects are controlled by constraining the radius of gyration of the IRF P-SF. An iterative technique suppresses sidelobes of the composite system P-SF.

  1. Optimal focal-plane restoration

    NASA Technical Reports Server (NTRS)

    Reichenbach, Stephen E.; Park, Stephen K.

    1989-01-01

    Image restoration can be implemented efficiently by calculating the convolution of the digital image and a small kernel during image acquisition. Processing the image in the focal-plane in this way requires less computation than traditional Fourier-transform-based techniques such as the Wiener filter and constrained least-squares filter. Here, the values of the convolution kernel that yield the restoration with minimum expected mean-square error are determined using a frequency analysis of the end-to-end imaging system. This development accounts for constraints on the size and shape of the spatial kernel and all the components of the imaging system. Simulation results indicate the technique is effective and efficient.

  2. Natural restoration basics for wetlands

    USGS Publications Warehouse

    Middleton, Beth A.

    2004-01-01

    Around the world, dams, diversions, and drainage systems reengineer rivers for navigation, farming, and urban development, and this has caused vast changes in the environmental conditions of the flood plains adjacent to these rivers (Middleton, 2002). Even though “flood pulses,” the periodic overflow of these rivers, were once the most important hydrological factor regulating all functions of the flood plain (Junk and others, 1986), now they have been reduced or eliminated along many of the world’s waterways (Sparks and others, 1998). These changes in river channels have created a hydrologic setting on flood plains that has not been conducive to restoration and nature conservation (Middleton, 2002). Consequently, USGS scientists are studying the long-term effects of hydrologic changes on flood plains, such as how the restoration of baldcypress (Taxodium distichum) swamps has been hindered because seeds cannot disperse or germinate without the seasonally driven high and low water levels associated with the flood pulse.

  3. Lake restoration technology transfer assessment

    SciTech Connect

    Daschbach, M.H.; Roe, E.M.; Sharpe, W.E.

    1982-06-01

    Based upon a review of the eutrophication problem and its impact on lake restoration (LR) programs, treatment of the relatively new problem of acid deposition and its impact on LR activities, consideration of the LR programs of the Environmental Protection Agency and several states, and a review of individual LR technology transfer publications, it is recommended that new LR technology transfer programs be given a low priority until more new information is available on the restoration of acidified lakes. Both primary and secondary users of LR research, technology transfer documents, and public awareness documents were considered in this assessment. Primary users included the general public and recreationists, lakeshore property owners, lake/homeowner associations, lake/sanitary districts, and research and environmental organizations; secondary users included state/county/local officials who administer/manage water-related regulations/activities. 4 tables.

  4. The bionic man: restoring mobility.

    PubMed

    Craelius, William

    2002-02-01

    Bionics engineers are making increasingly bold and successful use of their tools to restore mobility to persons with missing or nonfunctional limbs. These tools include the latest materials, minielectronics and megacomputers, advanced robotic mechanisms, and algorithms. With crucial help from their pioneering users, they are learning how and where the residual sensorimotor system can be tapped in order to transmit its intents to replacement or reactivated body parts.

  5. 15 CFR 990.55 - Restoration selection-developing restoration plans.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 3 2013-01-01 2013-01-01 false Restoration selection-developing... POLLUTION ACT REGULATIONS NATURAL RESOURCE DAMAGE ASSESSMENTS Restoration Planning Phase § 990.55 Restoration selection—developing restoration plans. (a) General. OPA requires that damages be based upon...

  6. 15 CFR 990.55 - Restoration selection-developing restoration plans.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 3 2014-01-01 2014-01-01 false Restoration selection-developing... POLLUTION ACT REGULATIONS NATURAL RESOURCE DAMAGE ASSESSMENTS Restoration Planning Phase § 990.55 Restoration selection—developing restoration plans. (a) General. OPA requires that damages be based upon...

  7. 15 CFR 990.55 - Restoration selection-developing restoration plans.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 3 2012-01-01 2012-01-01 false Restoration selection-developing... POLLUTION ACT REGULATIONS NATURAL RESOURCE DAMAGE ASSESSMENTS Restoration Planning Phase § 990.55 Restoration selection—developing restoration plans. (a) General. OPA requires that damages be based upon...

  8. 15 CFR 990.53 - Restoration selection-developing restoration alternatives.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 3 2014-01-01 2014-01-01 false Restoration selection-developing... OIL POLLUTION ACT REGULATIONS NATURAL RESOURCE DAMAGE ASSESSMENTS Restoration Planning Phase § 990.53 Restoration selection—developing restoration alternatives. (a) General. (1) If the information on...

  9. 32 CFR 644.452 - Minor restoration cases-determining extent of restoration required.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 4 2011-07-01 2011-07-01 false Minor restoration cases-determining extent of restoration required. 644.452 Section 644.452 National Defense Department of Defense (Continued) DEPARTMENT OF... Improvements § 644.452 Minor restoration cases—determining extent of restoration required. (a) In...

  10. 32 CFR 644.461 - Payment for restoration or settlement in lieu of restoration.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 4 2011-07-01 2011-07-01 false Payment for restoration or settlement in lieu of restoration. 644.461 Section 644.461 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY... § 644.461 Payment for restoration or settlement in lieu of restoration. Voucher forms, appropriate...

  11. 32 CFR 644.452 - Minor restoration cases-determining extent of restoration required.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Minor restoration cases-determining extent of restoration required. 644.452 Section 644.452 National Defense Department of Defense (Continued) DEPARTMENT OF... Improvements § 644.452 Minor restoration cases—determining extent of restoration required. (a) In...

  12. 32 CFR 644.461 - Payment for restoration or settlement in lieu of restoration.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Payment for restoration or settlement in lieu of restoration. 644.461 Section 644.461 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY... § 644.461 Payment for restoration or settlement in lieu of restoration. Voucher forms, appropriate...

  13. 32 CFR 644.453 - Major restoration cases-determining extent of restoration required.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 4 2011-07-01 2011-07-01 false Major restoration cases-determining extent of restoration required. 644.453 Section 644.453 National Defense Department of Defense (Continued) DEPARTMENT OF... Improvements § 644.453 Major restoration cases—determining extent of restoration required. (a)...

  14. 32 CFR 644.453 - Major restoration cases-determining extent of restoration required.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Major restoration cases-determining extent of restoration required. 644.453 Section 644.453 National Defense Department of Defense (Continued) DEPARTMENT OF... Improvements § 644.453 Major restoration cases—determining extent of restoration required. (a)...

  15. A highly conserved motif at the COOH terminus dictates endoplasmic reticulum exit and cell surface expression of NKCC2.

    PubMed

    Zaarour, Nancy; Demaretz, Sylvie; Defontaine, Nadia; Mordasini, David; Laghmani, Kamel

    2009-08-01

    Mutations in the apically located Na(+)-K(+)-2Cl(-) co-transporter, NKCC2, lead to type I Bartter syndrome, a life-threatening kidney disorder, yet the mechanisms underlying the regulation of mutated NKCC2 proteins in renal cells have not been investigated. Here, we identified a trihydrophobic motif in the distal COOH terminus of NKCC2 that was required for endoplasmic reticulum (ER) exit and surface expression of the co-transporter. Indeed, microscopic confocal imaging showed that a naturally occurring mutation depriving NKCC2 of its distal COOH-terminal region results in the absence of cell surface expression. Biotinylation assays revealed that lack of cell surface expression was associated with abolition of mature complex-glycosylated NKCC2. Pulse-chase analysis demonstrated that the absence of mature protein was not caused by reduced synthesis or increased rates of degradation of mutant co-transporters. Co-immunolocalization experiments revealed that these mutants co-localized with the ER marker protein-disulfide isomerase, demonstrating that they are retained in the ER. Cell treatment with proteasome or lysosome inhibitors failed to restore the loss of complex-glycosylated NKCC2, further eliminating the possibility that mutant co-transporters were processed by the Golgi apparatus. Serial truncation of the NKCC2 COOH terminus, followed by site-directed mutagenesis, identified hydrophobic residues (1081)LLV(1083) as an ER exit signal necessary for maturation of NKCC2. Mutation of (1081)LLV(1083) to AAA within the context of the full-length protein prevented NKCC2 ER exit independently of the expression system. This trihydrophobic motif is highly conserved in the COOH-terminal tails of all members of the cation-chloride co-transporter family, and thus may function as a common motif mediating their transport from the ER to the cell surface. Taken together, these data are consistent with a model whereby naturally occurring premature terminations that interfere with

  16. [Multiple agenesis and prosthetic restoration].

    PubMed

    Renault, P

    1990-03-01

    Cases of multiple agenesia present some difficulties in the treatment planing. Three situations may be encountered: limited agenesia, restored by a fixed, bonded or cemented prosthesis, multiple uni- or bimaxillary agenesia without remaining of deciduous teeth, restored by a fixed, bonded or cemented prosthesis or the partial adjacent prosthesis, multiple uni- or bimaxillary agenesia with remaining of deciduous teeth, restored by means of a supra-dental prosthesis. The first two situations have been described in dental literature and are relatively easy to treat. The same is not true for the third situation, where the decision to keep the temporary teeth considerably increases the difficulty of prosthetic restoration. This subject will be illustrated by the presentation of a clinical case of multiple bi-maxillary agenesia. The patient has: on the maxilla: an absence of 9 permanent teeth (18, 15, 14, 12, 22, 23, 24, 25, 28) and the presence of 4 deciduous teeth (62, 63, 64, 65), on the mandible: an absence of all permanent teeth, with the exception of 36 and 46, and the remaining of 4 deciduous teeth (75, 73, 83, 84). The remaining of deciduous teeth and the presence of a very high inter-arch space led to opting for dental coverage so as to keep the deciduous teeth and a proper vertical dimension. The patient wished to solve his "problem" in the maxilla first, and is not wanting to undergo the extraction of his deciduous teeth. The following therapeutic proposal was adapted: On the maxilla, a three-step procedure: first step: building of metal copings on 13, 16 and 26 and metal-ceramic crowns on 11 and 21, second step: building of telescop crowns on 16 and 26 and clasps on 13, 11 and 21, third step: casting of the removable partial denture framework and soldering to the telescop crowns and clasps. On the mandible, a provisional restoration using a supra-dental resin removable partial denture with ceramic occlusal surfaces was adopted. The aesthetic and functional

  17. Class II Resin Composites: Restorative Options.

    PubMed

    Patel, Minesh; Mehta, Shamir B; Banerji, Subir

    2015-10-01

    Tooth-coloured, resin composite restorations are amongst the most frequently prescribed forms of dental restoration to manage defects in posterior teeth. The attainment of a desirable outcome when placing posterior resin composite restorations requires the clinician to have a good understanding of the benefits (as well as the limitations) posed by this material, together with a sound knowledge of placement technique. Numerous protocols and materials have evolved to assist the dental operator with this type of demanding posterior restoration. With the use of case examples, four techniques available are reported here. CPD/Clinical Relevance: This article explores varying techniques for the restoration of Class II cavities using resin composite.

  18. The science and practice of river restoration

    NASA Astrophysics Data System (ADS)

    Wohl, Ellen; Lane, Stuart N.; Wilcox, Andrew C.

    2015-08-01

    River restoration is one of the most prominent areas of applied water-resources science. From an initial focus on enhancing fish habitat or river appearance, primarily through structural modification of channel form, restoration has expanded to incorporate a wide variety of management activities designed to enhance river process and form. Restoration is conducted on headwater streams, large lowland rivers, and entire river networks in urban, agricultural, and less intensively human-altered environments. We critically examine how contemporary practitioners approach river restoration and challenges for implementing restoration, which include clearly identified objectives, holistic understanding of rivers as ecosystems, and the role of restoration as a social process. We also examine challenges for scientific understanding in river restoration. These include: how physical complexity supports biogeochemical function, stream metabolism, and stream ecosystem productivity; characterizing response curves of different river components; understanding sediment dynamics; and increasing appreciation of the importance of incorporating climate change considerations and resiliency into restoration planning. Finally, we examine changes in river restoration within the past decade, such as increasing use of stream mitigation banking; development of new tools and technologies; different types of process-based restoration; growing recognition of the importance of biological-physical feedbacks in rivers; increasing expectations of water quality improvements from restoration; and more effective communication between practitioners and river scientists.

  19. Endoplasmic reticulum stress-induced apoptosis in the penumbra aggravates secondary damage in rats with traumatic brain injury

    PubMed Central

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

    2016-01-01

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

  20. Endoplasmic reticulum stress-induced apoptosis in the penumbra aggravates secondary damage in rats with traumatic brain injury.

    PubMed

    Sun, Guo-Zhu; Gao, Fen-Fei; Zhao, Zong-Mao; Sun, Hai; Xu, Wei; Wu, Li-Wei; He, Yong-Chang

    2016-08-01

    Neuronal apoptosis is mediated by intrinsic and extrinsic signaling pathways such as the membrane-mediated, mitochondrial, and endoplasmic reticulum stress pathways. Few studies have examined the endoplasmic reticulum-mediated apoptosis pathway in the penumbra after traumatic brain injury, and it remains unclear whether endoplasmic reticulum stress can activate the caspase-12-dependent apoptotic pathway in the traumatic penumbra. Here, we established rat models of fluid percussion-induced traumatic brain injury and found that protein expression of caspase-12, caspase-3 and the endoplasmic reticulum stress marker 78 kDa glucose-regulated protein increased in the traumatic penumbra 6 hours after injury and peaked at 24 hours. Furthermore, numbers of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-positive cells in the traumatic penumbra also reached peak levels 24 hours after injury. These findings suggest that caspase-12-mediated endoplasmic reticulum-related apoptosis is activated in the traumatic penumbra, and may play an important role in the pathophysiology of secondary brain injury. PMID:27651773

  1. Endoplasmic reticulum stress-induced apoptosis in the penumbra aggravates secondary damage in rats with traumatic brain injury

    PubMed Central

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

    2016-01-01

    Neuronal apoptosis is mediated by intrinsic and extrinsic signaling pathways such as the membrane-mediated, mitochondrial, and endoplasmic reticulum stress pathways. Few studies have examined the endoplasmic reticulum-mediated apoptosis pathway in the penumbra after traumatic brain injury, and it remains unclear whether endoplasmic reticulum stress can activate the caspase-12-dependent apoptotic pathway in the traumatic penumbra. Here, we established rat models of fluid percussion-induced traumatic brain injury and found that protein expression of caspase-12, caspase-3 and the endoplasmic reticulum stress marker 78 kDa glucose-regulated protein increased in the traumatic penumbra 6 hours after injury and peaked at 24 hours. Furthermore, numbers of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-positive cells in the traumatic penumbra also reached peak levels 24 hours after injury. These findings suggest that caspase-12-mediated endoplasmic reticulum-related apoptosis is activated in the traumatic penumbra, and may play an important role in the pathophysiology of secondary brain injury. PMID:27651773

  2. The Involvement of SMILE/TMTC3 in Endoplasmic Reticulum Stress Response

    PubMed Central

    Racapé, Maud; Duong Van Huyen, Jean-Paul; Danger, Richard; Giral, Magali; Bleicher, Françoise; Foucher, Yohann; Pallier, Annaïck; Pilet, Paul; Tafelmeyer, Petra; Ashton-Chess, Joanna; Dugast, Emilie; Pettré, Ségolène; Charreau, Béatrice; Soulillou, Jean-Paul; Brouard, Sophie

    2011-01-01

    Background Thestate of operational tolerance has been detected sporadically in some renal transplanted patients that stopped immunosuppressive drugs, demonstrating that allograft tolerance might exist in humans. Several years ago, a study by Brouard et al. identified a molecular signature of several genes that were significantly differentially expressed in the blood of such patients compared with patients with other clinical situations. The aim of the present study is to analyze the role of one of these molecules over-expressed in the blood of operationally tolerant patients, SMILE or TMTC3, a protein whose function is still unknown. Methodology/Principal Findings We first confirmed that SMILE mRNA is differentially expressed in the blood of operationally tolerant patients with drug-free long term graft function compared to stable and rejecting patients. Using a yeast two-hybrid approach and a colocalization study by confocal microscopy we furthermore report an interaction of SMILE with PDIA3, a molecule resident in the endoplasmic reticulum (ER). In accordance with this observation, SMILE silencing in HeLa cells correlated with the modulation of several transcripts involved in proteolysis and a decrease in proteasome activity. Finally, SMILE silencing increased HeLa cell sensitivity to the proteasome inhibitor Bortezomib, a drug that induces ER stress via protein overload, and increased transcript expression of a stress response protein, XBP-1, in HeLa cells and keratinocytes. Conclusion/Significance In this study we showed that SMILE is involved in the endoplasmic reticulum stress response, by modulating proteasome activity and XBP-1 transcript expression. This function of SMILE may influence immune cell behavior in the context of transplantation, and the analysis of endoplasmic reticulum stress in transplantation may reveal new pathways of regulation in long-term graft acceptance thereby increasing our understanding of tolerance. PMID:21603654

  3. N-Myristoyltransferase 1 interacts with calnexin at the endoplasmic reticulum.

    PubMed

    Dudek, Elzbieta; Millott, Robyn; Liu, Wen-Xin; Beauchamp, Erwan; Berthiaume, Luc G; Michalak, Marek

    2015-12-25

    Calnexin is a type 1 integral endoplasmic reticulum (ER) membrane molecular chaperone with a highly conserved C-terminal domain oriented to the cytoplasm. Protein N-myristoylation plays an important role in a wide variety of cellular signal transduction pathways and it is catalyzed by N-myristoyltransferase (NMT), a cytoplasmic and ER associated enzyme. Here using yeast two-hybrid screen, Western blot analysis, immunoprecipitation, immunolocalization and cellular fractionation we discovered that N-myristoyltransferase 1 interacts with calnexin at the ER. These observations point at a previously unrecognized contribution of calnexin to the retention of NMT1 at the ER membrane. PMID:26603938

  4. Radiosensitization of tumor cells through endoplasmic reticulum stress induced by PEGylated nanogel containing gold nanoparticles.

    PubMed

    Yasui, Hironobu; Takeuchi, Ryo; Nagane, Masaki; Meike, Shunsuke; Nakamura, Yoshinari; Yamamori, Tohru; Ikenaka, Yoshinori; Kon, Yasuhiro; Murotani, Hiroki; Oishi, Motoi; Nagasaki, Yukio; Inanami, Osamu

    2014-05-28

    High atomic number molecules, such as gold and platinum, are known to enhance the biological effect of X-irradiation. This study was aimed to determine the radiosensitizing potential of PEGylated nanogel containing gold nanoparticles (GNG) and the cellular mechanism involved. GNG pretreatment increased the levels of reproductive cell death and apoptosis induced by X-irradiation. GNG accumulated in cytoplasm and increased the expression of endoplasmic reticulum (ER) stress-related protein. GNG suppressed the repair capacity of DNA after X-irradiation by down-regulating DNA repair-related proteins. Our results suggest that GNG radiosensitized cells by enhancing apoptosis and impairing DNA repair capacity via ER stress induction.

  5. Regulation of Protein Secretion Through Controlled Aggregation in the Endoplasmic Reticulum

    NASA Astrophysics Data System (ADS)

    Rivera, Victor M.; Wang, Xiurong; Wardwell, Scott; Courage, Nancy L.; Volchuk, Allen; Keenan, Terence; Holt, Dennis A.; Gilman, Michael; Orci, Lelio; Cerasoli, Frank; Rothman, James E.; Clackson, Tim

    2000-02-01

    A system for direct pharmacologic control of protein secretion was developed to allow rapid and pulsatile delivery of therapeutic proteins. A protein was engineered so that it accumulated as aggregates in the endoplasmic reticulum. Secretion was then stimulated by a synthetic small-molecule drug that induces protein disaggregation. Rapid and transient secretion of growth hormone and insulin was achieved in vitro and in vivo. A regulated pulse of insulin secretion resulted in a transient correction of serum glucose concentrations in a mouse model of hyperglycemia. This approach may make gene therapy a viable method for delivery of polypeptides that require rapid and regulated delivery.

  6. Regulation of protein secretion through controlled aggregation in the endoplasmic reticulum.

    PubMed

    Rivera, V M; Wang, X; Wardwell, S; Courage, N L; Volchuk, A; Keenan, T; Holt, D A; Gilman, M; Orci, L; Cerasoli, F; Rothman, J E; Clackson, T

    2000-02-01

    A system for direct pharmacologic control of protein secretion was developed to allow rapid and pulsatile delivery of therapeutic proteins. A protein was engineered so that it accumulated as aggregates in the endoplasmic reticulum. Secretion was then stimulated by a synthetic small-molecule drug that induces protein disaggregation. Rapid and transient secretion of growth hormone and insulin was achieved in vitro and in vivo. A regulated pulse of insulin secretion resulted in a transient correction of serum glucose concentrations in a mouse model of hyperglycemia. This approach may make gene therapy a viable method for delivery of polypeptides that require rapid and regulated delivery. PMID:10657290

  7. The Yin-Yang Principle of Endoplasmic Reticulum Stress and oral cancer.

    PubMed

    Sarode, Gargi S; Sarode, Sachin C; Patil, Shankargouda

    2016-01-01

    The endoplasmic reticulum (ER) is an organelle, which performs several cellular functions and is thus an important site for maintaining cellular homeostasis. Sometimes pathways within the ER are disturbed, especially those regulating the protein folding, gene expression, cellular metabolism, and calcium signaling, and is called an "ER stress."(1) The accumulation of unfolded, misfolded, or damaged proteins can irreparably damage cellular functions and can pose a severe threat to the existence of the cell. Under such circumstances, ER functions become overwhelmed triggering the homeostatic "ER stress response" or "unfolded protein response" (UPR).(2). PMID:27595714

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

    PubMed

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

    2009-08-01

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

  9. Analysis of site-specific N-glycan remodeling in the endoplasmic reticulum and the Golgi.

    PubMed

    Hang, Ivan; Lin, Chia-wei; Grant, Oliver C; Fleurkens, Susanna; Villiger, Thomas K; Soos, Miroslav; Morbidelli, Massimo; Woods, Robert J; Gauss, Robert; Aebi, Markus

    2015-12-01

    The hallmark of N-linked protein glycosylation is the generation of diverse glycan structures in the secretory pathway. Dynamic, non-template-driven processes of N-glycan remodeling in the endoplasmic reticulum and the Golgi provide the cellular setting for structural diversity. We applied newly developed mass spectrometry-based analytics to quantify site-specific N-glycan remodeling of the model protein Pdi1p expressed in insect cells. Molecular dynamics simulation, mutational analysis, kinetic studies of in vitro processing events and glycan flux analysis supported the defining role of the protein in N-glycan processing. PMID:26240167

  10. Peptidyl prolyl cis-trans-isomerase activity associated with the lumen of the endoplasmic reticulum.

    PubMed Central

    Bose, S; Freedman, R B

    1994-01-01

    Peptidyl prolyl cis-trans-isomerase (PPI) activity was detected in microsomal fractions from bovine and rat liver. Extensive washing, proteinase and sonication treatments indicated that although some of this activity was due to adsorbed cytosolic enzymes, there was also an active but latent microsomal PPI activity. Density-gradient subfractionation indicated that activity was associated with vesicles derived from both the rough and the smooth endoplasmic reticulum (ER), suggesting that the activity was located within the ER lumen. The luminal PPI activity was inhibited by cyclosporin A and was active towards an unfolded protein substrate as well as towards the standard peptide substrate. PMID:8010971

  11. Isolation and fractionation of the endoplasmic reticulum from castor bean (Ricinus communis) endosperm for proteomic analyses.

    PubMed

    Simon, William J; Maltman, Daniel J; Slabas, Antoni R

    2008-01-01

    This chapter describes the preparation and isolation of highly purified endoplasmic reticulum (ER) from the endosperm of developing and germinating castor bean (Ricinus communis) seeds to provide a purified organelle fraction for differential proteomic analyses. The method uses a two-step ultracentrifugation protocol first described by Coughlan (1) and uses sucrose density gradients and a sucrose flotation step to yield purified ER devoid of other contaminating endomembrane material. Using a combination of one dimensional (1D) and two dimensional (2D) gel electrophoresis the complexity and reproducibility of the protein profile of the purified organelle is evaluated prior to detailed proteomic analyses using mass spectrometry based techniques.

  12. The endoplasmic reticulum exerts control over organelle streaming during cell expansion.

    PubMed

    Stefano, Giovanni; Renna, Luciana; Brandizzi, Federica

    2014-03-01

    Cytoplasmic streaming is crucial for cell homeostasis and expansion but the precise driving forces are largely unknown. In plants, partial loss of cytoplasmic streaming due to chemical and genetic ablation of myosins supports the existence of yet-unknown motors for organelle movement. Here we tested a role of the endoplasmic reticulum (ER) as propelling force for cytoplasmic streaming during cell expansion. Through quantitative live-cell analyses in wild-type Arabidopsis thaliana cells and mutants with compromised ER structure and streaming, we demonstrate that cytoplasmic streaming undergoes profound changes during cell expansion and that it depends on motor forces co-exerted by the ER and the cytoskeleton.

  13. The coupling of plasma membrane calcium entry to calcium uptake by endoplasmic reticulum and mitochondria

    PubMed Central

    García-Sancho, Javier

    2014-01-01

    Abstract Cross-talk between organelles and plasma membrane Ca2+ channels is essential for modulation of the cytosolic Ca2+ ([Ca2+]C) signals, but such modulation may differ among cells. In chromaffin cells Ca2+ entry through voltage-operated channels induces calcium release from the endoplasmic reticulum (ER) that amplifies the signal. [Ca2+]C microdomains as high as 20–50 μm are sensed by subplasmalemmal mitochondria, which accumulate large amounts of Ca2+ through the mitochondrial Ca2+ uniporter (MCU). Mitochondria confine the high-Ca2+ microdomains (HCMDs) to beneath the plasma membrane, where exocytosis of secretory vesicles happens. Cell core [Ca2+]C is much smaller (1–2 μm). By acting as a Ca2+ sink, mitochondria stabilise the HCMD in space and time. In non-excitable HEK293 cells, activation of store-operated Ca2+ entry, triggered by ER Ca2+ emptying, also generated subplasmalemmal HCMDs, but, in this case, most of the Ca2+ was taken up by the ER rather than by mitochondria. The smaller size of the [Ca2+]C peak in this case (about 2 μm) may contribute to this outcome, as the sarco-endoplasmic reticulum Ca2+ ATPase has much higher Ca2+ affinity than MCU. It is also possible that the relative positioning of organelles, channels and effectors, as well as cytoskeleton and accessory proteins plays an important role. Key points Cross-talk between organelles and plasma membrane Ca2+ channels modulates cytosolic Ca2+ signals in different ways. In chromaffin cells Ca2+ entry through voltage-operated channels is amplified by Ca2+ release from the endoplasmic reticulum (ER) and generates subplasmalemmal high Ca2+ microdomains (HCMDs) as high as 20–50 μm, which trigger exocytosis. Subplasmalemmal mitochondria take up Ca2+ from HCMDs and avoid progression of the Ca2+ wave towards the cell core. In non-excitable HEK293 cells activation of store-operated Ca2+ entry triggered by ER Ca2+ emptying also generates subplasmalemmal HCMDs of about 2 μm. In this case

  14. Multiresolution image gathering and restoration

    NASA Technical Reports Server (NTRS)

    Fales, Carl L.; Huck, Friedrich O.; Alter-Gartenberg, Rachel; Rahman, Zia-Ur

    1992-01-01

    In this paper we integrate multiresolution decomposition with image gathering and restoration. This integration leads to a Wiener-matrix filter that accounts for the aliasing, blurring, and noise in image gathering, together with the digital filtering and decimation in signal decomposition. Moreover, as implemented here, the Wiener-matrix filter completely suppresses the blurring and raster effects of the image-display device. We demonstrate that this filter can significantly improve the fidelity and visual quality produced by conventional image reconstruction. The extent of this improvement, in turn, depends on the design of the image-gathering device.

  15. Current status of zirconia restoration.

    PubMed

    Miyazaki, Takashi; Nakamura, Takashi; Matsumura, Hideo; Ban, Seiji; Kobayashi, Taira

    2013-10-01

    During the past decade, zirconia-based ceramics have been successfully introduced into the clinic to fabricate fixed dental prostheses (FDPs), along with a dental computer-aided/computer-aided manufacturing (CAD/CAM) system. In this article (1) development of dental ceramics, (2) the current status of dental CAD/CAM systems, (3) CAD/CAM and zirconia restoration, (4) bond between zirconia and veneering ceramics, (5) bond of zirconia with resin-based luting agents, (6) surface finish of zirconia restoration and antagonist enamel wear, and (7) clinical evaluation of zirconia restoration are reviewed. Yttria partially stabilized tetragonal zirconia polycrystalline (Y-TZP) showed better mechanical properties and superior resistance to fracture than other conventional dental ceramics. Furthermore, ceria-stabilized tetragonal zirconia polycrystalline and alumina nanocomposites (Ce-TZP/A) had the highest fracture toughness and had resistance to low-temperature aging degradation. Both zirconia-based ceramics have been clinically available as an alternative to the metal framework for fixed dental prostheses (FDPs). Marginal adaptation of zirconia-based FDPs is acceptable for clinical application. The most frequent clinical complication with zirconia-based FDPs was chipping of the veneering porcelain that was affected by many factors. The mechanism for the bonding between zirconia and veneering ceramics remains unknown. There was no clear evidence of chemical bonding and the bond strength between zirconia and porcelain was lower than that between metal and porcelain. There were two alternatives proposed that might avoid chipping of veneering porcelains. One was hybrid-structured FDPs comprising CAD/CAM-fabricated porcelain parts adhering to a CAD/CAM fabricated zirconia framework. Another option was full-contour zirconia FDPs using high translucent zirconia. Combined application of silica coating and/or silane coupler, and 10-methacryloyloxydecyl dihydrogen phosphate is

  16. Current status of zirconia restoration.

    PubMed

    Miyazaki, Takashi; Nakamura, Takashi; Matsumura, Hideo; Ban, Seiji; Kobayashi, Taira

    2013-10-01

    During the past decade, zirconia-based ceramics have been successfully introduced into the clinic to fabricate fixed dental prostheses (FDPs), along with a dental computer-aided/computer-aided manufacturing (CAD/CAM) system. In this article (1) development of dental ceramics, (2) the current status of dental CAD/CAM systems, (3) CAD/CAM and zirconia restoration, (4) bond between zirconia and veneering ceramics, (5) bond of zirconia with resin-based luting agents, (6) surface finish of zirconia restoration and antagonist enamel wear, and (7) clinical evaluation of zirconia restoration are reviewed. Yttria partially stabilized tetragonal zirconia polycrystalline (Y-TZP) showed better mechanical properties and superior resistance to fracture than other conventional dental ceramics. Furthermore, ceria-stabilized tetragonal zirconia polycrystalline and alumina nanocomposites (Ce-TZP/A) had the highest fracture toughness and had resistance to low-temperature aging degradation. Both zirconia-based ceramics have been clinically available as an alternative to the metal framework for fixed dental prostheses (FDPs). Marginal adaptation of zirconia-based FDPs is acceptable for clinical application. The most frequent clinical complication with zirconia-based FDPs was chipping of the veneering porcelain that was affected by many factors. The mechanism for the bonding between zirconia and veneering ceramics remains unknown. There was no clear evidence of chemical bonding and the bond strength between zirconia and porcelain was lower than that between metal and porcelain. There were two alternatives proposed that might avoid chipping of veneering porcelains. One was hybrid-structured FDPs comprising CAD/CAM-fabricated porcelain parts adhering to a CAD/CAM fabricated zirconia framework. Another option was full-contour zirconia FDPs using high translucent zirconia. Combined application of silica coating and/or silane coupler, and 10-methacryloyloxydecyl dihydrogen phosphate is

  17. Tensile strength of restorative resins.

    PubMed

    Zidan, O; Asmussen, E; Jørgensen, K D

    1980-06-01

    The purpose of the present work was to measure the tensile strength of restorative resins and to study the effect of the method of measurement on the recorded results. A direct pull method using dumb-bell shaped specimens was used. The tensile strength of the resins was also tested using the diametral compression method suggested by the A.D.A. It was found that the method of testing affects the results. Although the diametral compression method is a simple method, it cannot be considered reliable for all types of material. The tensile strength of the conventional composites was significantly higher than the tensile strength of the microfilled composites.

  18. Call to restore Mesopotamian marshlands

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    When the current military conflict in Iraq has concluded, a rehabilitation of that country should include a full assessment and action plan for restoring the marshlands of Mesopotamia, the United Nations Environment Programme said on 22 March.The marshlands, also known as the Fertile Crescent, could disappear within three to five years, according to UNEP.UNEP Executive Director Klaus Toepfer said the loss of the marshlands “is an environmental catastrophe for this region and underscores the huge pressures facing wetlands and freshwater ecosystems across the world.”

  19. Contribution of genetics to ecological restoration.

    PubMed

    Mijangos, Jose Luis; Pacioni, Carlo; Spencer, Peter B S; Craig, Michael D

    2015-01-01

    Ecological restoration of degraded ecosystems has emerged as a critical tool in the fight to reverse and ameliorate the current loss of biodiversity and ecosystem services. Approaches derived from different genetic disciplines are extending the theoretical and applied frameworks on which ecological restoration is based. We performed a search of scientific articles and identified 160 articles that employed a genetic approach within a restoration context to shed light on the links between genetics and restoration. These articles were then classified on whether they examined association between genetics and fitness or the application of genetics in demographic studies, and on the way the studies informed restoration practice. Although genetic research in restoration is rapidly growing, we found that studies could make better use of the extensive toolbox developed by applied fields in genetics. Overall, 41% of reviewed studies used genetic information to evaluate or monitor restoration, and 59% provided genetic information to guide prerestoration decision-making processes. Reviewed studies suggest that restoration practitioners often overlook the importance of including genetic aspects within their restoration goals. Even though there is a genetic basis influencing the provision of ecosystem services, few studies explored this relationship. We provide a view of research gaps, future directions and challenges in the genetics of restoration.

  20. Predicting restorability of incompetent criminal defendants.

    PubMed

    Mossman, Douglas

    2007-01-01

    U.S. courts frequently require forensic examiners to offer opinions concerning the likelihood that criminal defendants found incompetent to stand trial can have their competence "restored" through treatment. Yet no jurisdiction has established legal guidelines for testimony concerning restorability, and several authors have suggested that mental health professionals cannot accurately predict whether treatment to restore competence will succeed. This study asked whether reliable information that is consistently available at the time of examination might support empirically grounded opinions about the likelihood of restoration. Using records from all 351 inpatient pretrial defendants who underwent competence restoration at a state psychiatric hospital from 1995 through 1999, I evaluated whether several types of information that are reliable and that could consistently be made available to forensic examiners--including evaluees' demographic characteristics, diagnoses, symptom patterns, criminal charges, number of prior public sector hospitalizations, and cumulative prior length of stay (LOS)--would predict outcome of restoration efforts. I modeled the probability of successful restoration using logistic regression equations, and evaluated the equations' predictive accuracy using k-fold cross-validation and receiver operating characteristic (ROC) analysis. Lower probability of restoration was associated with having a misdemeanor charge, longer cumulative LOS, older age, and diagnoses of mental retardation, schizophrenia, and schizoaffective disorder. Although the overall rate of successful restoration for felony defendants was 75 percent, logistic equations allowed selection of subgroups with high predicted probabilities of restoration (>90%) and low probabilities of restoration (<35%). In cross-validation simulations, predictive equations had ROC areas of 0.727 for all defendants, and 0.735 for felony defendants. These findings provide scientific support for testimony

  1. Predicting restorability of incompetent criminal defendants.

    PubMed

    Mossman, Douglas

    2007-01-01

    U.S. courts frequently require forensic examiners to offer opinions concerning the likelihood that criminal defendants found incompetent to stand trial can have their competence "restored" through treatment. Yet no jurisdiction has established legal guidelines for testimony concerning restorability, and several authors have suggested that mental health professionals cannot accurately predict whether treatment to restore competence will succeed. This study asked whether reliable information that is consistently available at the time of examination might support empirically grounded opinions about the likelihood of restoration. Using records from all 351 inpatient pretrial defendants who underwent competence restoration at a state psychiatric hospital from 1995 through 1999, I evaluated whether several types of information that are reliable and that could consistently be made available to forensic examiners--including evaluees' demographic characteristics, diagnoses, symptom patterns, criminal charges, number of prior public sector hospitalizations, and cumulative prior length of stay (LOS)--would predict outcome of restoration efforts. I modeled the probability of successful restoration using logistic regression equations, and evaluated the equations' predictive accuracy using k-fold cross-validation and receiver operating characteristic (ROC) analysis. Lower probability of restoration was associated with having a misdemeanor charge, longer cumulative LOS, older age, and diagnoses of mental retardation, schizophrenia, and schizoaffective disorder. Although the overall rate of successful restoration for felony defendants was 75 percent, logistic equations allowed selection of subgroups with high predicted probabilities of restoration (>90%) and low probabilities of restoration (<35%). In cross-validation simulations, predictive equations had ROC areas of 0.727 for all defendants, and 0.735 for felony defendants. These findings provide scientific support for testimony

  2. Dialogue between endoplasmic reticulum and mitochondria as a key actor of vascular dysfunction associated to metabolic disorders.

    PubMed

    Safiedeen, Zainab; Andriantsitohaina, Ramaroson; Martinez, M Carmen

    2016-08-01

    Metabolic syndrome due to its association with increased risk of cardiovascular diseases and cardiac mortality, comprises a cluster of metabolic abnormalities such as central obesity, hyperglycemia, dyslipidemia, and hypertension. Recent studies have shown that metabolic syndrome patients exhibit impaired nitric oxide-mediated vasodilatation leading to endothelial dysfunction in addition to insulin resistance. Interestingly, development and maintenance of the unfolded protein response of the endoplasmic reticulum stress revealed a surprisingly direct link with metabolic syndrome and endothelial dysfunction. On the other hand, in metabolic disorders, interaction between endoplasmic reticulum and mitochondria is mandatory for the generation of mitochondrial oxidative stress and perturbation of mitochondrial function accounting, at least in part, for vascular dysfunction. Herein, we review the impact of the dialogue between endoplasmic reticulum and mitochondria in modulating the cellular signals governing vascular alterations associated to metabolic disorders.

  3. Mitochondrial DNA, restoring Beethovens music.

    PubMed

    Merheb, Maxime; Vaiedelich, Stéphane; Maniguet, Thiérry; Hänni, Catherine

    2016-01-01

    Great ancient composers have endured many obstacles and constraints which are very difficult to understand unless we perform the restoration process of ancient music. Species identification in leather used during manufacturing is the key step to start such a restoration process in order to produce a facsimile of a museum piano. Our study reveals the species identification in the leather covering the hammer head in a piano created by Erard in 1802. This is the last existing piano similar to the piano that Beethoven used with its leather preserved in its original state. The leather sample was not present in a homogeneous piece, yet combined with glue. Using a DNA extraction method that avoids PCR inhibitors; we discovered that sheep and cattle are the origin of the combination. To identify the species in the leather, we focused on the amounts of mitochondrial DNA in both leather and glue and results have led us to the conclusion that the leather used to cover the hammer head in this piano was made of cattle hide. PMID:24617463

  4. Mitochondrial DNA, restoring Beethovens music.

    PubMed

    Merheb, Maxime; Vaiedelich, Stéphane; Maniguet, Thiérry; Hänni, Catherine

    2016-01-01

    Great ancient composers have endured many obstacles and constraints which are very difficult to understand unless we perform the restoration process of ancient music. Species identification in leather used during manufacturing is the key step to start such a restoration process in order to produce a facsimile of a museum piano. Our study reveals the species identification in the leather covering the hammer head in a piano created by Erard in 1802. This is the last existing piano similar to the piano that Beethoven used with its leather preserved in its original state. The leather sample was not present in a homogeneous piece, yet combined with glue. Using a DNA extraction method that avoids PCR inhibitors; we discovered that sheep and cattle are the origin of the combination. To identify the species in the leather, we focused on the amounts of mitochondrial DNA in both leather and glue and results have led us to the conclusion that the leather used to cover the hammer head in this piano was made of cattle hide.

  5. Microtubule-dependent motility and orientation of the cortical endoplasmic reticulum in elongating characean internodal cells.

    PubMed

    Foissner, Ilse; Menzel, Diedrik; Wasteneys, Geoffrey O

    2009-03-01

    Motility of the endoplasmic reticulum (ER) is predominantly microtubule- dependent in animal cells but thought to be entirely actomyosin-dependent in plant cells. Using live cell imaging and transmission electron microscopy to examine ER motility and structural organization in giant internodal cells of characean algae, we discovered that at the onset of cell elongation, the cortical ER situated near the plasma membrane formed a tight meshwork of predominantly transverse ER tubules that frequently coaligned with microtubules. Microtubule depolymerization increased mesh size and decreased the dynamics of the cortical ER. In contrast, perturbing the cortical actin array with cytochalasins did not affect the transverse orientation but decreased mesh size and increased ER dynamics. Our data suggest that myosin-dependent ER motility is confined to the ER strands in the streaming endoplasm, while the more sedate cortical ER uses microtubule-based mechanisms for organization and motility during early stages of cell elongation. We show further that the ER has an inherent, NEM-sensitive dynamics which can be altered via interaction with the cytoskeleton and that tubule formation and fusion events are cytoskeleton-independent.

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

    PubMed

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

    2016-06-16

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

  7. Intrinsic membrane glycoproteins with cytosol-oriented sugars in the endoplasmic reticulum

    SciTech Connect

    Abeijon, C.; Hirschberg, C.B.

    1988-02-01

    The authors have examined the topography of N-acetylglucosamine-terminating glycoproteins in membranes from rat liver smooth and rough endoplasmic reticulum (SER and RER). It was found that some of these glycoproteins are intrinsic membrane proteins with their sugars facing the cytosolic rather than the luminal side. This conclusion was reached by using vesicles from the SER and RER that were sealed and of the same topographical orientation as in vivo. These vesicles were incubated with UDP-(/sup 14/C)galactose (which does not enter the vesicles) and saturating amounts of soluble galactosyltransferase from milk, an enzyme that does not penetrate the lumen of the vesicles and that specifically adds galactose to terminal N-acetylglucosamine in a ..beta..1-4 linkage. Radioactive galactose was mainly transferred to SER proteins of apparent molecular mass 56 and 110 kDa and to a lesser extent RER and SER proteins of apparent molecular mass 46 and 72 kDa. These proteins are intrinsic membrane proteins, based on the inability of sodium carbonate at pH 11.5 to remove them from the membranes. Studies with peptide N-glycosidase F and chemical ..beta..-elimination showed that the 56-kDa protein of the SER vesicles contained terminal N-acetylglucosamine in an O-linkage to the protein. The above results suggest that some sugars of glycoproteins in the endoplasmic reticulum may attain their final orientation in the membrane by mechanisms yet to be determined.

  8. The Dictyostelium discoideum GPHR Ortholog Is an Endoplasmic Reticulum and Golgi Protein with Roles during Development

    PubMed Central

    Deckstein, Jaqueline; van Appeldorn, Jennifer; Tsangarides, Marios; Yiannakou, Kyriacos; Müller, Rolf; Stumpf, Maria; Sukumaran, Salil K.; Eichinger, Ludwig

    2014-01-01

    Dictyostelium discoideum GPHR (Golgi pH regulator)/Gpr89 is a developmentally regulated transmembrane protein present on the endoplasmic reticulum (ER) and the Golgi apparatus. Transcript levels are low during growth and vary during development, reaching high levels during the aggregation and late developmental stages. The Arabidopsis ortholog was described as a G protein-coupled receptor (GPCR) for abscisic acid present at the plasma membrane, whereas the mammalian ortholog is a Golgi apparatus-associated anion channel functioning as a Golgi apparatus pH regulator. To probe its role in D. discoideum, we generated a strain lacking GPHR. The mutant had different growth characteristics than the AX2 parent strain, exhibited changes during late development, and formed abnormally shaped small slugs and fruiting bodies. An analysis of development-specific markers revealed that their expression was disturbed. The distributions of the endoplasmic reticulum and the Golgi apparatus were unaltered at the immunofluorescence level. Likewise, their functions did not appear to be impaired, since membrane proteins were properly processed and glycosylated. Also, changes in the external pH were sensed by the ER, as indicated by a pH-sensitive ER probe, as in the wild type. PMID:25380752

  9. Lipid homeostasis is involved in plasma membrane and endoplasmic reticulum stress in Pichia pastoris.

    PubMed

    Zhang, Meng; Yu, Qilin; Liang, Chen; Zhang, Biao; Li, Mingchun

    2016-09-16

    Maintaining cellular lipid composition is essential for many cell processes. Our previous study has demonstrated that Spt23 is an important transcription factor within the cell and responsible for the regulation of fatty acid desaturase genes. Disruption of SPT23 results in increased lipid saturation. In the present study, we found that lipid saturation caused by SPT23 deletion exhibited a growth defect under ethanol stress and increased chitin contents. Ergosterol synthesis-related genes were up-regulated to protect cells from plasma membrane damage in the presence of ethanol. The cell wall stress caused by increased chitin contents could not be attenuated by up-regulation of phospholipids synthesis-related genes in spt23Δ. Besides, lipid saturation induced expression of unfolded protein response (UPR) genes and reactive oxygen species (ROS) accumulation followed by activation of the cellular antioxidant system, which is associated with endoplasmic reticulum functions. Taken together, our data suggested that lipid homeostasis has a close connection with cell responses to both plasma membrane stress and endoplasmic reticulum stress. PMID:27524240

  10. Evidence of endoplasmic reticulum-related Ca sup 2+ ATPase in human microvascular endothelial cells

    SciTech Connect

    Bikfalvi, A.; Enouf, J.; Bredoux, R.; Dupuy, E.; Bourdeau, N.; Levy-Toledano, S.; Tobelem, G. ); Lompre, A. )

    1989-09-01

    The authors demonstrated by immunological and molecular methods the presence of a reticulum endoplasmic-related Ca{sup 2+}-ATPase in human omental microvascular endothelial cells (HOME cells). HOME cells reacted positively with a previously characterized sarcoplasmic reticulum Ca{sup 2+}-ATPase antibody as demonstrated by indirect immunofluorescence. Western blotting revealed that the antibody recognized a 95-100 kDa protein. {sup 35}S-Metabolic labeling led to the detection of a similar protein with which the purified sarcoplasmic reticulum Ca{sup 2+}-ATPase compete. Dot-blotting experiments indicated that a substantial amount of Ca{sup 2+}-ATPase was present in HOME cell membranes. In addition, Northern blot analysis using a cDNA probe from cardiac sarcoplasmic reticulum showed the presence of mRNA species of 4 kb. As these experiments were conducted in comparison with cell types with well-defined Ca{sup 2+}-ATPases, the results suggest the presence of a endoplasmic reticulum-related Ca{sup 2+}-ATPase in HOME cells.

  11. Oxidative stress contributes to autophagy induction in response to endoplasmic reticulum stress in Chlamydomonas reinhardtii.

    PubMed

    Pérez-Martín, Marta; Pérez-Pérez, María Esther; Lemaire, Stéphane D; Crespo, José L

    2014-10-01

    The accumulation of unfolded/misfolded proteins in the endoplasmic reticulum (ER) results in the activation of stress responses, such as the unfolded protein response or the catabolic process of autophagy to ultimately recover cellular homeostasis. ER stress also promotes the production of reactive oxygen species, which play an important role in autophagy regulation. However, it remains unknown whether reactive oxygen species are involved in ER stress-induced autophagy. In this study, we provide evidence connecting redox imbalance caused by ER stress and autophagy activation in the model unicellular green alga Chlamydomonas reinhardtii. Treatment of C. reinhardtii cells with the ER stressors tunicamycin or dithiothreitol resulted in up-regulation of the expression of genes encoding ER resident endoplasmic reticulum oxidoreductin1 oxidoreductase and protein disulfide isomerases. ER stress also triggered autophagy in C. reinhardtii based on the protein abundance, lipidation, cellular distribution, and mRNA levels of the autophagy marker ATG8. Moreover, increases in the oxidation of the glutathione pool and the expression of oxidative stress-related genes were detected in tunicamycin-treated cells. Our results revealed that the antioxidant glutathione partially suppressed ER stress-induced autophagy and decreased the toxicity of tunicamycin, suggesting that oxidative stress participates in the control of autophagy in response to ER stress in C. reinhardtii In close agreement, we also found that autophagy activation by tunicamycin was more pronounced in the C. reinhardtii sor1 mutant, which shows increased expression of oxidative stress-related genes.

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

    PubMed Central

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

    2016-01-01

    Calcium homeostasis is crucial to eukaryotic cell survival. By acting as an enzyme cofactor and a second messenger in several signal transduction pathways, the calcium ion controls many essential biological processes. Inside the endoplasmic reticulum (ER) calcium concentration is carefully regulated to safeguard the correct folding and processing of secretory proteins. By using the model organism Saccharomyces cerevisiae we show that calcium shortage leads to a slowdown of cell growth and metabolism. Accumulation of unfolded proteins within the calcium-depleted lumen of the endoplasmic reticulum (ER stress) triggers the unfolded protein response (UPR) and generates a state of oxidative stress that decreases cell viability. These effects are severe during growth on rapidly fermentable carbon sources and can be mitigated by decreasing the protein synthesis rate or by inducing cellular respiration. Calcium homeostasis, protein biosynthesis and the unfolded protein response are tightly intertwined and the consequences of facing calcium starvation are determined by whether cellular energy production is balanced with demands for anabolic functions. Our findings confirm that the connections linking disturbance of ER calcium equilibrium to ER stress and UPR signaling are evolutionary conserved and highlight the crucial role of metabolism in modulating the effects induced by calcium shortage. PMID:27305947

  13. Effects of a Sublethal and Transient Stress of the Endoplasmic Reticulum on the Mitochondrial Population.

    PubMed

    Vannuvel, Kayleen; Van Steenbrugge, Martine; Demazy, Catherine; Ninane, Noëlle; Fattaccioli, Antoine; Fransolet, Maude; Renard, Patricia; Raes, Martine; Arnould, Thierry

    2016-09-01

    Endoplasmic reticulum (ER) and mitochondria are not discrete intracellular organelles but establish close physical and functional interactions involved in several biological processes including mitochondrial bioenergetics, calcium homeostasis, lipid synthesis, and the regulation of apoptotic cell death pathways. As many cell types might face a transient and sublethal ER stress during their lifetime, it is thus likely that the adaptive UPR response might affect the mitochondrial population. The aim of this work was to study the putative effects of a non-lethal and transient endoplasmic reticulum stress on the mitochondrial population in HepG2 cells. The results show that thapsigargin and brefeldin A, used to induce a transient and sublethal ER stress, rapidly lead to the fragmentation of the mitochondrial network associated with a decrease in mitochondrial membrane potential, O2 (•-) production and less efficient respiration. These changes in mitochondrial function are transient and preceded by the phosphorylation of JNK. Inhibition of JNK activation by SP600125 prevents the decrease in O2 (•-) production and the mitochondrial network fragmentation observed in cells exposed to the ER stress but has no impact on the reduction of the mitochondrial membrane potential. In conclusion, our data show that a non-lethal and transient ER stress triggers a rapid activation of JNK without inducing apoptosis, leading to the fragmentation of the mitochondrial network and a reduction of O2 (•-) production. J. Cell. Physiol. 231: 1913-1931, 2016. © 2015 Wiley Periodicals, Inc.

  14. Endoplasmic reticulum stress activation mediates Ginseng Rg3-induced anti-gallbladder cancer cell activity.

    PubMed

    Wu, Keren; Li, Ning; Sun, Huaqin; Xu, Tao; Jin, Fa; Nie, Jifeng

    2015-10-23

    In the current study, we examined the potential effect of Ginsenoside Rg3 against gallbladder cancer cells, the underlying signaling mechanisms were also studied. We demonstrated that Rg3 exerted potent cytotoxic and pro-apoptotic activity against established and primary human gallbladder cancer cells. Yet it was safe to non-cancerous gallbladder epithelial cells. At the molecular level, we showed that Rg3 induced endoplasmic reticulum (ER) stress activation, the latter was evidenced by C/EBP homologous protein (CHOP) upregulation, inositol-requiring enzyme 1 (IRE1)/PKR-like endoplasmic reticulum kinase (PERK) phosphorylations, and caspase-12 activation in gallbladder cancer cells. Reversely, the ER stress inhibitor salubrinal, the caspase-12 inhibitor z-ATAD-fmk as well as CHOP shRNA knockdown significantly attenuated Rg3-induced cytotoxicity against gallbladder cancer cells. In vivo, we showed that Rg3 oral administration significantly inhibited GBC-SD gallbladder cancer xenograft growth in nude mice, its activity was, however, compromised with co-administration of the ER stress inhibitor salubrinal. Thus, we suggest that ER stress activation mediates Ginseng Rg3-induced anti-gallbladder cancer cell activity in vitro and in vivo. PMID:26361144

  15. Bufotalin-induced apoptosis in osteoblastoma cells is associated with endoplasmic reticulum stress activation.

    PubMed

    Zhu, Yun-Rong; Xu, Yong; Fang, Jian-Feng; Zhou, Feng; Deng, Xiong-Wei; Zhang, Yun-Qing

    2014-08-15

    The search for novel and more efficient chemo-agents against malignant osteoblastoma is important. In this study, we examined the potential anti-osteoblastoma function of bufotalin, and studied the underlying mechanisms. Our results showed that bufotalin induced osteoblastoma cell death and apoptosis in dose- and time-dependent manners. Further, bufotalin induced endoplasmic reticulum (ER) stress activation in osteoblastoma cells, the latter was detected by the induction of C/EBP homologous protein (CHOP), phosphorylation of inositol-requiring enzyme 1 (IRE1) and PKR-like endoplasmic reticulum kinase (PERK), as well as caspase-12 activation. Conversely, the ER stress inhibitor salubrinal, the caspase-12 inhibitor z-ATAD-fmk as well as CHOP depletion by shRNA significantly inhibited bufotalin-induced osteoblastoma cell death and apoptosis. Finally, by using a mice xenograft model, we demonstrated that bufotalin inhibited U2OS osteoblastoma cell growth in vivo. In summary, our results suggest that ER stress contributes to bufotalin-induced apoptosis in osteoblastoma cells. Bufotalin might be investigated as a novel anti-osteoblastoma agent. PMID:25068992

  16. Endoplasmic reticulum stress plays critical role in brain damage after chronic intermittent hypoxia in growing rats.

    PubMed

    Cai, Xiao-Hong; Li, Xiu-Cui; Jin, Sheng-Wei; Liang, Dong-Shi; Wen, Zheng-Wang; Cao, Hong-Chao; Mei, Hong-Fang; Wu, Ying; Lin, Zhong-Dong; Wang, Liang-Xing

    2014-07-01

    Obstructive sleep apnea hypopnea syndrome (OSAHS) in children is associated with multiple system morbidities. Cognitive dysfunction as a result of central nervous system complication has been reported in children with OSAHS. However, the underlying mechanisms are poorly understood. Endoplasmic reticulum stress (ERS)-related apoptosis plays an important role in various diseases of the central nervous system, but very little is known about the role of ERS in mediating pathophysiological reactions to cognitive dysfunction in OSAHS. Chronic intermittent hypoxia (CIH) exposures, modeling OSAHS, across 2 and 4weeks in growing rats made more reference memory errors, working memory errors and total memory errors in the 8-Arm radial maze task, increased significantly TUNEL positive cells, upregulated the unfolded protein response in the hippocampus and prefrontal cortex as evidenced by increased phosphorylation of PKR-like endoplasmic reticulum kinase, inositol-requiring enzyme l and some downstream products. A selective inhibitor of eukaryotic initiation factor-2a dephosphorylation, salubrinal, prevented C/EBP-homologous protein activation in the hippocampus and prefrontal cortex throughout hypoxia/reoxygenation exposure. Our findings suggest that ERS mediated cell apoptosis may be one of the underlying mechanisms of cognitive dysfunction in OSAHS children. Further, a specific ERS inhibitor Salubrinal should be tested for neuroprotection against CIH-induced injury. PMID:24810321

  17. The Endoplasmic Reticulum Chaperone Calnexin Is a NADPH Oxidase NOX4 Interacting Protein*

    PubMed Central

    Prior, Kim-Kristin; Wittig, Ilka; Leisegang, Matthias S.; Groenendyk, Jody; Weissmann, Norbert; Michalak, Marek; Jansen-Dürr, Pidder; Shah, Ajay M.; Brandes, Ralf P.

    2016-01-01

    Within the family of NADPH oxidases, NOX4 is unique as it is predominantly localized in the endoplasmic reticulum, has constitutive activity, and generates hydrogen peroxide (H2O2). We hypothesize that these features are consequences of a so far unidentified NOX4-interacting protein. Two-dimensional blue native (BN) electrophorese combined with SDS-PAGE yielded NOX4 to reside in macromolecular complexes. Interacting proteins were screened by quantitative SILAC (stable isotope labeling of amino acids in cell culture) co-immunoprecipitation (Co-IP) in HEK293 cells stably overexpressing NOX4. By this technique, several interacting proteins were identified with calnexin showing the most robust interaction. Calnexin also resided in NOX4-containing complexes as demonstrated by complexome profiling from BN-PAGE. The calnexin NOX4 interaction could be confirmed by reverse Co-IP and proximity ligation assay, whereas NOX1, NOX2, or NOX5 did not interact with calnexin. Calnexin deficiency as studied in mouse embryonic fibroblasts from calnexin−/− mice or in response to calnexin shRNA reduced cellular NOX4 protein expression and reactive oxygen species formation. Our results suggest that endogenous NOX4 forms macromolecular complexes with calnexin, which are needed for the proper maturation, processing, and function of NOX4 in the endoplasmic reticulum. PMID:26861875

  18. Mechanisms for exporting large-sized cargoes from the endoplasmic reticulum.

    PubMed

    Saito, Kota; Katada, Toshiaki

    2015-10-01

    Cargo proteins exported from the endoplasmic reticulum to the Golgi apparatus are typically transported in coat protein complex II (COPII)-coated vesicles of 60-90 nm diameter. Several cargo molecules including collagens and chylomicrons form structures that are too large to be accommodated by these vesicles, but their secretion still requires COPII proteins. Here, we first review recent progress on large cargo secretions derived especially from animal models and human diseases, which indicate the importance of COPII proteins. We then discuss the recent isolation of specialized factors that modulate the process of COPII-dependent cargo formation to facilitate the exit of large-sized cargoes from the endoplasmic reticulum. Based on these findings, we propose a model that describes the importance of the GTPase cycle for secretion of oversized cargoes. Next, we summarize reports that describe the structures of COPII proteins and how these results provide insight into the mechanism of assembly of the large cargo carriers. Finally, we discuss what issues remain to be solved in the future.

  19. THE DELICATE BALANCE BETWEEN SECRETED PROTEIN FOLDING AND ENDOPLASMIC RETICULUM-ASSOCIATED DEGRADATION IN HUMAN PHYSIOLOGY

    PubMed Central

    Guerriero, Christopher J.; Brodsky, Jeffrey L.

    2014-01-01

    Protein folding is a complex, error-prone process that often results in an irreparable protein by-product. These by-products can be recognized by cellular quality control machineries and targeted for proteasome-dependent degradation. The folding of proteins in the secretory pathway adds another layer to the protein folding “problem,” as the endoplasmic reticulum maintains a unique chemical environment within the cell. In fact, a growing number of diseases are attributed to defects in secretory protein folding, and many of these by-products are targeted for a process known as endoplasmic reticulum-associated degradation (ERAD). Since its discovery, research on the mechanisms underlying the ERAD pathway has provided new insights into how ERAD contributes to human health during both normal and diseases states. Links between ERAD and disease are evidenced from the loss of protein function as a result of degradation, chronic cellular stress when ERAD fails to keep up with misfolded protein production, and the ability of some pathogens to coopt the ERAD pathway. The growing number of ERAD substrates has also illuminated the differences in the machineries used to recognize and degrade a vast array of potential clients for this pathway. Despite all that is known about ERAD, many questions remain, and new paradigms will likely emerge. Clearly, the key to successful disease treatment lies within defining the molecular details of the ERAD pathway and in understanding how this conserved pathway selects and degrades an innumerable cast of substrates. PMID:22535891

  20. The protective effect of the earthworm active ingredients on hepatocellular injury induced by endoplasmic reticulum stress.

    PubMed

    Wang, Qi; Duan, Leng-Xin; Xu, Zheng-Shun; Wang, Jian-Gang; Xi, Shou-Min

    2016-08-01

    The earthworm is a widely used Chinese herbal medicine. There are more than 40 prescriptions including earthworms in the "Compendium of Materia Medica". TCM theory holds that earthworms exert antispasmodic and antipyretic effects through the liver meridian to calm the liver. However, the clinical effect of earthworms on liver injury has not been clearly demonstrated. We have previously established a method to extract the active ingredients from earthworms (hereinafter referred to as EWAs) [1]. In the present study, we observed protective effect of the EWAs on tunicamycin-induced ERS (endoplasmic reticulum stress) model in human hepatic L02 cells. The results showed that the EWAs promote proliferation and reduced apoptosis of ERS model in L02 cells (P<0.01). The up-regulation of ERS-related proteins, including PERK (protein kinase RNA-like endoplasmic reticulum kinase), eIF2a (eukaryotic translation initiation factor 2a), ATF4 (activating transcription factor 4) and CHOP (CCAAT/enhancer binding protein homologous protein), in L02 cell under ERS was inhibited by treatment of the EWAs (P<0.01). In summary, our data suggest the EWAs can significant attenuate ERS-induced hepatocyte injury via PERK-eIF2a-ATF4 pathway. PMID:27470367

  1. Unveiling the Role of the Integrated Endoplasmic Reticulum Stress Response in Leishmania Infection – Future Perspectives

    PubMed Central

    Dias-Teixeira, K. L.; Pereira, R. M.; Silva, J. S.; Fasel, N.; Aktas, B. H.; Lopes, U. G.

    2016-01-01

    The integrated endoplasmic reticulum stress response (IERSR) is an evolutionarily conserved adaptive mechanism that ensures endoplasmic reticulum (ER) homeostasis and cellular survival in the presence of stress including nutrient deprivation, hypoxia, and imbalance of Ca+ homeostasis, toxins, and microbial infection. Three transmembrane proteins regulate integrated signaling pathways that comprise the IERSR, namely, IRE-1 that activates XBP-1, the pancreatic ER kinase (PERK) that phosphorylates the eukaryotic translation initiation factor 2 and transcription factor 6 (ATF6). The roles of IRE-1, PERK, and ATF4 in viral and some bacterial infections are well characterized. The role of IERSR in infections by intracellular parasites is still poorly understood, although one could anticipate that IERSR may play an important role on the host’s cell response. Recently, our group reported the important aspects of XBP-1 activation in Leishmania amazonensis infection. It is, however, necessary to address the relevance of the other IERSR branches, together with the possible role of IERSR in infections by other Leishmania species, and furthermore, to pursue the possible implications in the pathogenesis and control of parasite replication in macrophages. PMID:27499755

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

    PubMed Central

    Folch-Puy, Emma; Panisello, Arnau; Oliva, Joan; Lopez, Alexandre; Castro Benítez, Carlos; Adam, René; Roselló-Catafau, Joan

    2016-01-01

    The endoplasmic reticulum (ER) is involved in calcium homeostasis, protein folding and lipid biosynthesis. Perturbations in its normal functions lead to a condition called endoplasmic reticulum stress (ERS). This can be triggered by many physiopathological conditions such as alcoholic steatohepatitis, insulin resistance or ischemia-reperfusion injury. The cell reacts to ERS by initiating a defensive process known as the unfolded protein response (UPR), which comprises cellular mechanisms for adaptation and the safeguarding of cell survival or, in cases of excessively severe stress, for the initiation of the cell death program. Recent experimental data suggest the involvement of ERS in ischemia/reperfusion injury (IRI) of the liver graft, which has been considered as one of major problems influencing outcome after liver transplantation. The purpose of this review is to summarize updated data on the molecular mechanisms of ERS/UPR and the consequences of this pathology, focusing specifically on solid organ preservation and liver transplantation models. We will also discuss the potential role of ERS, beyond the simple adaptive response and the regulation of cell death, in the modification of cell functional properties and phenotypic changes. PMID:27231901

  3. Involvement of endoplasmic reticulum stress in capsaicin-induced apoptosis of human pancreatic cancer cells.

    PubMed

    Lin, Shengzhang; Zhang, Jianhong; Chen, Hui; Chen, Kangjie; Lai, Fuji; Luo, Jiang; Wang, Zhaohong; Bu, Heqi; Zhang, Riyuan; Li, Honghai; Tong, Hongfei

    2013-01-01

    Capsaicin, main pungent ingredient of hot chilli peppers, has been shown to have anticarcinogenic effect on various cancer cells through multiple mechanisms. In this study, we investigated the apoptotic effect of capsaicin on human pancreatic cancer cells in both in vitro and in vivo systems, as well as the possible mechanisms involved. In vitro, treatment of both the pancreatic cancer cells (PANC-1 and SW1990) with capsaicin resulted in cells growth inhibition, G0/G1 phase arrest, and apoptosis in a dose-dependent manner. Knockdown of growth arrest- and DNA damage-inducible gene 153 (GADD153), a marker of the endoplasmic-reticulum-stress- (ERS-) mediated apoptosis pathway, by specific siRNA attenuated capsaicin-induced apoptosis both in PANC-1 and SW1990 cells. Moreover, in vivo studies capsaicin effectively inhibited the growth and metabolism of pancreatic cancer and prolonged the survival time of pancreatic cancer xenograft tumor-induced mice. Furthermore, capsaicin increased the expression of some key ERS markers, including glucose-regulated protein 78 (GRP78), phosphoprotein kinase-like endoplasmic reticulum kinase (phosphoPERK), and phosphoeukaryotic initiation factor-2 α (phospho-eIF2 α ), activating transcription factor 4 (ATF4) and GADD153 in tumor tissues. In conclusion, we for the first time provide important evidence to support the involvement of ERS in the induction of apoptosis in pancreatic cancer cells by capsaicin.

  4. Role of p97 and Syntaxin 5 in the Assembly of Transitional Endoplasmic Reticulum

    PubMed Central

    Roy, Line; Bergeron, John J.M.; Lavoie, Christine; Hendriks, Rob; Gushue, Jennifer; Fazel, Ali; Pelletier, Amélie; Morré, D. James; Subramaniam, V. Nathan; Hong, Wanjin; Paiement, Jacques

    2000-01-01

    Transitional endoplasmic reticulum (tER) consists of confluent rough and smooth endoplasmic reticulum (ER) domains. In a cell-free incubation system, low-density microsomes (1.17 g cc−1) isolated from rat liver homogenates reconstitute tER by Mg2+GTP- and Mg2+ATP-hydrolysis–dependent membrane fusion. The ATPases associated with different cellular activities protein p97 has been identified as the relevant ATPase. The ATP depletion by hexokinase or treatment with either N-ethylmaleimide or anti-p97 prevented assembly of the smooth ER domain of tER. High-salt washing of low-density microsomes inhibited assembly of the smooth ER domain of tER, whereas the readdition of purified p97 with associated p47 promoted reconstitution. The t-SNARE syntaxin 5 was observed within the smooth ER domain of tER, and antisyntaxin 5 abrogated formation of this same membrane compartment. Thus, p97 and syntaxin 5 regulate assembly of the smooth ER domain of tER and hence one of the earliest membrane differentiated components of the secretory pathway. PMID:10930451

  5. The endoplasmic reticulum and casein-containing vesicles contribute to milk fat globule membrane.

    PubMed

    Honvo-Houéto, Edith; Henry, Céline; Chat, Sophie; Layani, Sarah; Truchet, Sandrine

    2016-10-01

    During lactation, mammary epithelial cells secrete huge amounts of milk from their apical side. The current view is that caseins are secreted by exocytosis, whereas milk fat globules are released by budding, enwrapped by the plasma membrane. Owing to the number and large size of milk fat globules, the membrane surface needed for their release might exceed that of the apical plasma membrane. A large-scale proteomics analysis of both cytoplasmic lipid droplets and secreted milk fat globule membranes was used to decipher the cellular origins of the milk fat globule membrane. Surprisingly, differential analysis of protein profiles of these two organelles strongly suggest that, in addition to the plasma membrane, the endoplasmic reticulum and the secretory vesicles contribute to the milk fat globule membrane. Analysis of membrane-associated and raft microdomain proteins reinforces this possibility and also points to a role for lipid rafts in milk product secretion. Our results provide evidence for a significant contribution of the endoplasmic reticulum to the milk fat globule membrane and a role for SNAREs in membrane dynamics during milk secretion. These novel aspects point to a more complex model for milk secretion than currently envisioned.

  6. A few positively charged residues slow movement of a polypeptide chain across the endoplasmic reticulum membrane.

    PubMed

    Yamagishi, Marifu; Onishi, Yukiko; Yoshimura, Shotaro; Fujita, Hidenobu; Imai, Kenta; Kida, Yuichiro; Sakaguchi, Masao

    2014-08-26

    Many polypeptide chains are translocated across and integrated into the endoplasmic reticulum membrane through protein-conducting channels. During the process, amino acid sequences of translocating polypeptide chains are scanned by the channels and classified to be retained in the membrane or translocated into the lumen. We established an experimental system with which the kinetic effect of each amino acid residue on the polypeptide chain movement can be analyzed with a time resolution of tens of seconds. Positive charges greatly slow movement; only two lysine residues caused a remarkable slow down, and their effects were additive. The lysine residue was more effective than arginine. In contrast, clusters comprising three residues of each of the other 18 amino acids had little effect on chain movement. We also demonstrated that a four lysine cluster can exert the effect after being fully exposed from the ribosome. We concluded that as few as two to three residues of positively charged amino acids can slow the movement of the nascent polypeptide chain across the endoplasmic reticulum membrane. This effect provides a fundamental basis of the topogenic function of positively charged amino acids. PMID:25093244

  7. Oxidative stress contributes to autophagy induction in response to endoplasmic reticulum stress in Chlamydomonas reinhardtii.

    PubMed

    Pérez-Martín, Marta; Pérez-Pérez, María Esther; Lemaire, Stéphane D; Crespo, José L

    2014-10-01

    The accumulation of unfolded/misfolded proteins in the endoplasmic reticulum (ER) results in the activation of stress responses, such as the unfolded protein response or the catabolic process of autophagy to ultimately recover cellular homeostasis. ER stress also promotes the production of reactive oxygen species, which play an important role in autophagy regulation. However, it remains unknown whether reactive oxygen species are involved in ER stress-induced autophagy. In this study, we provide evidence connecting redox imbalance caused by ER stress and autophagy activation in the model unicellular green alga Chlamydomonas reinhardtii. Treatment of C. reinhardtii cells with the ER stressors tunicamycin or dithiothreitol resulted in up-regulation of the expression of genes encoding ER resident endoplasmic reticulum oxidoreductin1 oxidoreductase and protein disulfide isomerases. ER stress also triggered autophagy in C. reinhardtii based on the protein abundance, lipidation, cellular distribution, and mRNA levels of the autophagy marker ATG8. Moreover, increases in the oxidation of the glutathione pool and the expression of oxidative stress-related genes were detected in tunicamycin-treated cells. Our results revealed that the antioxidant glutathione partially suppressed ER stress-induced autophagy and decreased the toxicity of tunicamycin, suggesting that oxidative stress participates in the control of autophagy in response to ER stress in C. reinhardtii In close agreement, we also found that autophagy activation by tunicamycin was more pronounced in the C. reinhardtii sor1 mutant, which shows increased expression of oxidative stress-related genes. PMID:25143584

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

    PubMed

    Folch-Puy, Emma; Panisello, Arnau; Oliva, Joan; Lopez, Alexandre; Castro Benítez, Carlos; Adam, René; Roselló-Catafau, Joan

    2016-01-01

    The endoplasmic reticulum (ER) is involved in calcium homeostasis, protein folding and lipid biosynthesis. Perturbations in its normal functions lead to a condition called endoplasmic reticulum stress (ERS). This can be triggered by many physiopathological conditions such as alcoholic steatohepatitis, insulin resistance or ischemia-reperfusion injury. The cell reacts to ERS by initiating a defensive process known as the unfolded protein response (UPR), which comprises cellular mechanisms for adaptation and the safeguarding of cell survival or, in cases of excessively severe stress, for the initiation of the cell death program. Recent experimental data suggest the involvement of ERS in ischemia/reperfusion injury (IRI) of the liver graft, which has been considered as one of major problems influencing outcome after liver transplantation. The purpose of this review is to summarize updated data on the molecular mechanisms of ERS/UPR and the consequences of this pathology, focusing specifically on solid organ preservation and liver transplantation models. We will also discuss the potential role of ERS, beyond the simple adaptive response and the regulation of cell death, in the modification of cell functional properties and phenotypic changes. PMID:27231901

  9. Guidelines for Direct Adhesive Composite Restoration.

    PubMed

    Society Of Cariology And Endodontology, Chinese Stomatological Association Csa

    2015-01-01

    Direct adhesive composite restoration, a technique to restore tooth defects by bonding composite resin materials, has been widely used in the restoration of dental caries or other tooth defects. Retention of composite resin restoration mainly relies on bonding strength between the materials and dental tissue. The clinical outcomes rely greatly on the regulated clinical practice of dentists. In 2011, the Society of Cariology and Endodontology of Chinese Stomatological Association (CSA) published the 'Practices and evaluation criteria of composite resin bonded restoration (Discussion Version)'. Since then, opinions and comments regarding the 'Discussion Version' have been widely circulated within the Society. The final version of the guideline was based on systematic reviews of scientific literature and requirements for the edit of technical guidelines, and through several rounds of discussions, revisions and supplements. The society recommends this guideline for clinicians to use in their practices, when conducting direct composite restorations.

  10. Long-term reinforced fixed provisional restorations.

    PubMed

    Galindo, D; Soltys, J L; Graser, G N

    1998-06-01

    Extensive prosthodontic treatment often requires fabrication of long-term provisional restorations. Numerous materials and techniques have been described for prolonged insertion of interim restorations. This article describes a procedure for fabrication of long-term reinforced heat-processed provisional restorations based on a diagnostic wax-up. Reinforced heat-processed provisional restorations reduced flexure, which minimizes progressive loss of cement and diminished the possibility of recurrent decay. Occlusal stability and vertical dimension were maintained because of greater wear resistance. Occlusion, tooth contours, and pontic design developed in the provisional restoration were duplicated in the definitive restoration. The use of a matrix from a diagnostic wax-up facilitated fabrication of the prosthesis, and made the procedure less time-consuming and more predictable.

  11. [Odontogenic maxillary sinusitis caused by dental restoration].

    PubMed

    Sato, Kiminori

    2014-06-01

    We report herein on 5 patients with odontogenic maxillary sinusitis caused by a dental restoration (caries cutting, cavity preparation, inlay restoration). Odontogenic maxillary sinusitis was noted following dental restoration. Even though the pulp cavity and dental pulp were intact, the odontogenic maxillary sinusitis occurred caused by an apical lesion. Infection by way of the dentinal tubules was suggested to be a cause of the pathophysiology. Endoscopic sinus surgery was indicated in patients with intractable odontogenic maxillary sinusitis caused by the dental restoration. Cone-beam x-ray CT was useful for the accurate diagnosis of odontogenic maxillary sinusitis caused by a dental restoration. Physicians should thus be aware of the possibility that a tooth, which has undergone dental restoration, may cause odontogenic maxillary sinusitis.

  12. Posterior restorations--a clinical view.

    PubMed

    Jedynakiewicz, N M; Martin, N

    2001-01-01

    This paper examines the state-of-the-art in the direct restoration of posterior teeth. The existing paradigms for the management of caries are questioned and some existing methods of cavity preparation are reviewed. Dental restorations need to be durable but able to adapt to a changing environment brought about by wear of the adjacent tooth substance and by fatigue processes within the tooth itself. The wear of restorative materials needs to be matched to that of the tooth, otherwise differential loss of either the restorative material or the enamel may destabilize the occlusion. Esthetic instability due to natural darkening of the tooth with age, punctuated by clinical intervention with bleaching procedures, adds a further dimension to the concept of a permanent restoration. Clinical methods that minimize the disruptive effects of dental restorations upon the remaining tooth structure are a continuing challenge.

  13. Quantitative Proteomic Analyses of Human Cytomegalovirus-Induced Restructuring of Endoplasmic Reticulum-Mitochondrial Contacts at Late Times of Infection*

    PubMed Central

    Zhang, Aiping; Williamson, Chad D.; Wong, Daniel S.; Bullough, Matthew D.; Brown, Kristy J.; Hathout, Yetrib; Colberg-Poley, Anamaris M.

    2011-01-01

    Endoplasmic reticulum-mitochondrial contacts, known as mitochondria-associated membranes, regulate important cellular functions including calcium signaling, bioenergetics, and apoptosis. Human cytomegalovirus is a medically important herpesvirus whose growth increases energy demand and depends upon continued cell survival. To gain insight into how human cytomegalovirus infection affects endoplasmic reticulum-mitochondrial contacts, we undertook quantitative proteomics of mitochondria-associated membranes using differential stable isotope labeling by amino acids in cell culture strategy and liquid chromatography-tandem MS analysis. This is the first reported quantitative proteomic analyses of a suborganelle during permissive human cytomegalovirus infection. Human fibroblasts were uninfected or human cytomegalovirus-infected for 72 h. Heavy mitochondria-associated membranes were isolated from paired unlabeled, uninfected cells and stable isotope labeling by amino acids in cell culture-labeled, infected cells and analyzed by liquid chromatography-tandem MS analysis. The results were verified by a reverse labeling experiment. Human cytomegalovirus infection dramatically altered endoplasmic reticulum-mitochondrial contacts by late times. Notable is the increased abundance of several fundamental networks in the mitochondria-associated membrane fraction of human cytomegalovirus-infected fibroblasts. Chaperones, including HSP60 and BiP, which is required for human cytomegalovirus assembly, were prominently increased at endoplasmic reticulum-mitochondrial contacts after infection. Minimal translational and translocation machineries were also associated with endoplasmic reticulum-mitochondrial contacts and increased after human cytomegalovirus infection as were glucose regulated protein 75 and the voltage dependent anion channel, which can form an endoplasmic reticulum-mitochondrial calcium signaling complex. Surprisingly, mitochondrial metabolic enzymes and cytosolic

  14. Can Viral Videos Help Beaver Restore Streams?

    NASA Astrophysics Data System (ADS)

    Castro, J. M.; Pollock, M. M.; Lewallen, G.; Jordan, C.; Woodruff, K.

    2015-12-01

    Have you watched YouTube lately? Did you notice the plethora of cute animal videos? Researchers, including members of our Beaver Restoration Research team, have been studying the restoration potential of beaver for decades, yet in the past few years, beaver have gained broad acclaim and some much deserved credit for restoration of aquatic systems in North America. Is it because people can now see these charismatic critters in action from the comfort of their laptops? While the newly released Beaver Restoration Guidebook attempts to answer many questions, sadly, this is not one of them. We do, however, address the use of beaver (Castor canadensis) in stream, wetland, and floodplain restoration and discuss the many positive effects of beaver on fluvial ecosystems. Our team, composed of researchers from NOAA National Marine Fisheries Service, US Fish and Wildlife Service, US Forest Service, and Portland State University, has developed a scientifically rigorous, yet accessible, practitioner's guide that provides a synthesis of the best available science for using beaver to improve ecosystem functions. Divided into two broad sections -- Beaver Ecology and Beaver Restoration and Management -- the guidebook focuses on the many ways in which beaver improve habitat, primarily through the construction of dams that impound water and retain sediment. In Beaver Ecology, we open with a discussion of the general effects that beaver dams have on physical and biological processes, and we close with "Frequently Asked Questions" and "Myth Busters". In Restoration and Management, we discuss common emerging restoration techniques and methods for mitigating unwanted beaver effects, followed by case studies from pioneering practitioners who have used many of these beaver restoration techniques in the field. The lessons they have learned will help guide future restoration efforts. We have also included a comprehensive beaver ecology library of over 1400 references from scientific journals

  15. Placement technique for direct posterior composite restorations.

    PubMed

    Javaheri, D S

    2001-04-01

    Due to improved materials, instrumentation, and placement techniques, composite resins have overcome the traditional complications associated with wear resistance, microleakage, sensitivity, and tight anatomical contacts. Composite resins have been utilized with increased frequency for direct posterior restorations capable of satisfying the growing aesthetic expectations of contemporary dental patients. When properly placed, posterior composites can provide successful and predictable restorations. This article presents clinical considerations for the aesthetic conservation of posterior restorations with composite resin materials.

  16. 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.

  17. Fast image restoration without boundary artifacts.

    PubMed

    Reeves, Stanley J

    2005-10-01

    Fast Fourier transform (FFT)-based restorations are fast, but at the expense of assuming that the blurring and deblurring are based on circular convolution. Unfortunately, when the opposite sides of the image do not match up well in intensity, this assumption can create significant artifacts across the image. If the pixels outside the measured image window are modeled as unknown values in the restored image, boundary artifacts are avoided. However, this approach destroys the structure that makes the use of the FFT directly applicable, since the unknown image is no longer the same size as the measured image. Thus, the restoration methods available for this problem no longer have the computational efficiency of the FFT. We propose a new restoration method for the unknown boundary approach that can be implemented in a fast and flexible manner. We decompose the restoration into a sum of two independent restorations. One restoration yields an image that comes directly from a modified FFT-based approach. The other restoration involves a set of unknowns whose number equals that of the unknown boundary values. By summing the two, the artifacts are canceled. Because the second restoration has a significantly reduced set of unknowns, it can be calculated very efficiently even though no circular convolution structure exists. PMID:16238051

  18. Composite veneering of complex amalgam restorations.

    PubMed

    Demarco, Flávio Fernando; Zanchi, César Henrique; Bueno, Márcia; Piva, Evandro

    2007-01-01

    In large posterior cavities, indirect restorations could provide improved performance when compared to direct restorations, but with higher cost and removal of sound tooth structure. Improved mechanical properties have resulted in good clinical performance for amalgam in large cavities but without an esthetic appearance. Resin composites have become popular for posterior restorations, mainly because of good esthetic results. A restorative technique is presented that combines the esthetic properties of directly bonded resin composite and the wide range of indications for amalgam in stress-bearing areas.

  19. Clinical guidelines for indirect resin restorations.

    PubMed

    Shannon, A

    1997-06-01

    Ongoing advances in adhesive dentistry have made it possible to successfully and predictably bond tooth-supporting restorations using conservative preparation techniques. Improvements in the durability and esthetic properties of tooth-colored restorative materials have also increased the range of available treatment options. However, dentists have been slow to accept both direct and indirect posterior esthetics. This article provides a step-by-step technique for practitioners who choose to treat their patients with indirect resin esthetic restorations. It will not discuss other posterior restorative treatment techniques or materials (i.e. gold, porcelain, amalgam, bonded amalgam, or direct resin).

  20. Esthetic restoration of discolored primary incisors.

    PubMed

    Margolis, Fred S

    2005-01-01

    Restoring primary teeth can be a strenuous task for many dentists who would like to have an esthetic, easy-to-use and relatively quick restoration for children. But, the restoration of carious, fractured or discolored primary incisors gives the dentist the satisfaction of knowing that he/she has restored the smile and self-confidence of a growing child. This article describes a technique which is relatively easy and produces a beautiful outcome in a relatively short time. The author has used the technique in hundreds of children for over twenty-five years. Modifications in the technique have been made as newer materials and techniques have evolved. PMID:15739584

  1. River Restoration for a Changing Climate

    NASA Astrophysics Data System (ADS)

    Beechie, T. J.; Pollock, M. M.; Pess, G. R.; Roni, P.

    2012-12-01

    Future climate scenarios suggest that riverine habitats will be significantly altered in the next few decades, forcing managers to ask whether and how river restoration activities should be altered to accommodate climate change. Obvious questions include: Will climate change alter river flow and temperature enough to reduce action effectiveness? What types of restoration actions are more likely to remain effective in a climate altered future? To help address these questions, we reviewed literature on habitat restoration actions and river processes to determine the degree to which different restoration actions are likely to either ameliorate a climate effect or increase habitat diversity and resilience. Key findings are that restoring floodplain connectivity and re-aggrading incised channels ameliorate both stream flow and temperature changes and increase lateral connectivity, whereas restoring in-stream flows can ameliorate decreases in low flows as well as stream temperature increases. Other restoration actions (e.g., reducing sediment supply, in-stream rehabilitation) are much less likely to ameliorate climate change effects. In general, actions that restore watershed and ecosystem processes are most likely to be robust to climate change effects because they allow river channels and riverine ecosystems to evolve in response to shifting stream flow and temperature regimes. We offer a decision support process to illustrate how to evaluate whether a project design should be altered to accommodate climate change effects, and show examples of restoration actions that are likely to be resilient to a changing climate.

  2. Expediting environmental restoration at a reduced cost

    SciTech Connect

    Johnson, G.R.; Plack, D.A.

    1994-12-31

    With Congress appropriating approximately $1.0--1.5 Billion each year for Department of Defense (DOD) Environmental Restoration Program (DERP), every effort must be made to find ways to use these funds efficiently and effectively to nations hazardous waste sites. Each federal agency involved in environmental restoration is striving to find smarter, faster ways to accomplish this service. The Omaha District Corps of Engineers, Hazardous and Toxic Waste Branch (Omaha) and the Air Combat Command Installation Restoration Branch (ACC) have teamed up to develop and implement an innovative Accelerated Clean-up Program which with the President`s edict for expedited installation environmental restoration.

  3. Seven-year clinical evaluation of painful cracked teeth restored with a direct composite restoration.

    PubMed

    Opdam, Niek J M; Roeters, Joost J M; Loomans, Bas A C; Bronkhorst, Ewald M

    2008-07-01

    The purpose of this study was to investigate long-term clinical effectiveness of treating painful cracked teeth with a direct bonded composite resin restoration. The hypothesis tested was that cracked teeth treated with or without cuspal coverage showed the same performance. Forty-one patients attended a dental practice with a painful cracked tooth that was restored with a direct composite resin restoration. Twenty teeth were restored without and 21 with cuspal coverage. After 7 years, 40 teeth could be evaluated. Three teeth without cuspal coverage needed an endodontic treatment, of which 2 failed as a result of fracture. No significant differences were found for tooth or pulp survival. Three more repairable restoration failures were recorded. Mean annual failure rate of restorations without cuspal coverage was 6%; no failures in restorations with cuspal coverage occurred (P = .009). A direct bonded composite resin restoration can be a successful treatment for a cracked tooth.

  4. Surgical procedures for voice restoration

    PubMed Central

    Nawka, Tadeus; Hosemann, Werner

    2005-01-01

    Surgical procedures for voice restoration serve to improve oral communication by better vocal function. They comprise of phonomicrosurgery, with direct and indirect access to the larynx; laryngoplasty; laryngeal injections; and surgical laryngeal reinnervation. The basis for modern surgical techniques for voice disorders is the knowledge about the ultrastructure of the vocal folds and the increasing experience of surgeons in voice surgery, while facing high social and professional demands on the voice. Vocal activity limitation and participation restriction has become more important in the artistic and social areas. A number of surgical methods that have been developed worldwide for this reason, are presented in this article. Functional oriented surgery has to meet high standards. The diagnostics of vocal function has to be multi-dimensional in order to determine the indication and the appropriate surgical intervention. PMID:22073062

  5. Quercetin attenuates the effects of H2O2 on endoplasmic reticulum morphology and tyrosinase export from the endoplasmic reticulum in melanocytes.

    PubMed

    Guan, Cuiping; Xu, Wen; Hong, Weisong; Zhou, Miaoni; Lin, Fuquan; Fu, Lifang; Liu, Dongyin; Xu, Aie

    2015-06-01

    Swollen endoplasmic reticulum (ER) is commonly observed in the melanocytes of vitiligo patients; however, the cause and proteins involved in this remain to be elucidated. Oxidative stress has been reported to be involved in the pathogenesis of vitiligo and previous studies have demonstrated that hydrogen peroxide (H2O2) induced melanocyte apoptosis, whereas quercetin exhibited cytoprotective activities against the effects of H2O2. The aim of the present study was to further investigate the role of H2O2 in the ER of melanocytes as well as its role in the export of tyrosinase from ER; in addition, the present study aimed to determine the mechanism by which quercetin protects against the effects of H2O2. The results demonstrated that melanocyte cells treated with H2O2 presented with swollen ER; however, a normal ER configuration was observed in untreated cells as well as quercetin/H2O2‑treated cells. Furthermore, H2O2 inhibited tyrosinase export from the ER and decreased expression levels of tyrosinase; however, quercetin was found to attenuate the effects induced by H2O2. In conclusion, the results of the present study confirmed the hypothesis that H2O2 induced ER dilation and hindered functional tyrosinase export from the ER of melanocytes. It was also found that quercetin significantly weakened these effects mediated by H2O2, therefore it may have the potential for use in the treatment of vitiligo.

  6. ERManI (Endoplasmic Reticulum Class I α-Mannosidase) Is Required for HIV-1 Envelope Glycoprotein Degradation via Endoplasmic Reticulum-associated Protein Degradation Pathway.

    PubMed

    Zhou, Tao; Frabutt, Dylan A; Moremen, Kelley W; Zheng, Yong-Hui

    2015-09-01

    Previously, we reported that the mitochondrial translocator protein (TSPO) induces HIV-1 envelope (Env) degradation via the endoplasmic reticulum (ER)-associated protein degradation (ERAD) pathway, but the mechanism was not clear. Here we investigated how the four ER-associated glycoside hydrolase family 47 (GH47) α-mannosidases, ERManI, and ER-degradation enhancing α-mannosidase-like (EDEM) proteins 1, 2, and 3, are involved in the Env degradation process. Ectopic expression of these four α-mannosidases uncovers that only ERManI inhibits HIV-1 Env expression in a dose-dependent manner. In addition, genetic knock-out of the ERManI gene MAN1B1 using CRISPR/Cas9 technology disrupts the TSPO-mediated Env degradation. Biochemical studies show that HIV-1 Env interacts with ERManI, and between the ERManI cytoplasmic, transmembrane, lumenal stem, and lumenal catalytic domains, the catalytic domain plays a critical role in the Env-ERManI interaction. In addition, functional studies show that inactivation of the catalytic sites by site-directed mutagenesis disrupts the ERManI activity. These studies identify ERManI as a critical GH47 α-mannosidase in the ER-associated protein degradation pathway that initiates the Env degradation and suggests that its catalytic domain and enzymatic activity play an important role in this process.

  7. Differential proteomic analysis of the endoplasmic reticulum from developing and germinating seeds of castor (Ricinus communis) identifies seed protein precursors as significant components of the endoplasmic reticulum.

    PubMed

    Maltman, Daniel J; Gadd, Stephen M; Simon, William J; Slabas, Antoni R

    2007-05-01

    The endoplasmic reticulum is a major compartment of storage protein and lipid biosynthesis. Maximal synthesis of these storage compounds occurs during seed development with breakdown occurring during germination. In this study, we have isolated four independent preparations of ER from both developing and germinating seeds of castor bean (Ricinus communis) and used 2-D DIGE, and a combination of PMF and MS/MS sequencing, to quantify and identify differences in protein complement at both stages. Ninety protein spots in the developing seeds are up-regulated and 19 individual proteins were identified, the majority of these are intermediates of seed storage synthesis and protein folding. The detection of these transitory storage proteins in the ER is discussed in terms of protein trafficking and processing. In germinating seed ER 15 spots are elevated, 5 of which were identified, amongst them was malate synthetase which is a component of the glyoxysome which is believed to originate from the ER. Notably no proteins involved in complex lipid biosynthesis were identified in the urea soluble ER fraction indicating that they are probably all integral membrane proteins.

  8. The Cytosolic Nucleoprotein of the Plant-Infecting Bunyavirus Tomato Spotted Wilt Recruits Endoplasmic Reticulum–Resident Proteins to Endoplasmic Reticulum Export Sites[C][W

    PubMed Central

    Ribeiro, Daniela; Jung, Maartje; Moling, Sjef; Borst, Jan Willem; Goldbach, Rob; Kormelink, Richard

    2013-01-01

    In contrast with animal-infecting viruses, few known plant viruses contain a lipid envelope, and the processes leading to their membrane envelopment remain largely unknown. Plant viruses with lipid envelopes include viruses of the Bunyaviridae, which obtain their envelope from the Golgi complex. The envelopment process is predominantly dictated by two viral glycoproteins (Gn and Gc) and the viral nucleoprotein (N). During maturation of the plant-infecting bunyavirus Tomato spotted wilt, Gc localizes at endoplasmic reticulum (ER) membranes and becomes ER export competent only upon coexpression with Gn. In the presence of cytosolic N, Gc remains arrested in the ER but changes its distribution from reticular into punctate spots. Here, we show that these areas correspond to ER export sites (ERESs), distinct ER domains where glycoprotein cargo concentrates prior to coat protein II vesicle–mediated transport to the Golgi. Gc concentration at ERES is mediated by an interaction between its cytoplasmic tail (CT) and N. Interestingly, an ER-resident calnexin provided with Gc-CT was similarly recruited to ERES when coexpressed with N. Furthermore, disruption of actin filaments caused the appearance of a larger amount of smaller ERES loaded with N-Gc complexes, suggesting that glycoprotein cargo concentration acts as a trigger for de novo synthesis of ERES. PMID:24045023

  9. Effect of pioglitazone treatment on endoplasmic reticulum stress response in human adipose and in palmitate-induced stress in human liver and adipose cell lines.

    PubMed

    Das, Swapan K; Chu, Winston S; Mondal, Ashis K; Sharma, Neeraj K; Kern, Philip A; Rasouli, Neda; Elbein, Steven C

    2008-08-01

    Obesity and elevated cytokine secretion result in a chronic inflammatory state and may cause the insulin resistance observed in type 2 diabetes. Recent studies suggest a key role for endoplasmic reticulum stress in hepatocytes and adipocytes from obese mice, resulting in reduced insulin sensitivity. To address the hypothesis that thiazolidinediones, which improve peripheral insulin sensitivity, act in part by reducing the endoplasmic reticulum stress response, we tested subcutaneous adipose tissue from 20 obese volunteers treated with pioglitazone for 10 wk. We also experimentally induced endoplasmic reticulum stress using palmitate, tunicamycin, and thapsigargin in the human HepG2 liver cell line with or without pioglitazone pretreatment. We quantified endoplasmic reticulum stress response by measuring both gene expression and phosphorylation. Pioglitazone significantly improved insulin sensitivity in human volunteers (P = 0.002) but did not alter markers of endoplasmic reticulum stress. Differences in pre- and posttreatment endoplasmic reticulum stress levels were not correlated with changes in insulin sensitivity or body mass index. In vitro, palmitate, thapsigargin, and tunicamycin but not oleate induced endoplasmic reticulum stress in HepG2 cells, including increased transcripts CHOP, ERN1, GADD34, and PERK, and increased XBP1 splicing along with phosphorylation of eukaryotic initiation factor eIF2alpha, JNK1, and c-jun. Although patterns of endoplasmic reticulum stress response differed among palmitate, tunicamycin, and thapsigargin, pioglitazone pretreatment had no significant effect on any measure of endoplasmic reticulum stress, regardless of the inducer. Together, our data suggest that improved insulin sensitivity with pioglitazone is not mediated by a reduction in endoplasmic reticulum stress.

  10. Optimal load shedding and restoration

    NASA Astrophysics Data System (ADS)

    Xu, Ding

    Load shedding is an emergency control action in power systems that can save systems from a wide-area blackout. Underfrequency load shedding, steady state load shedding, and voltage load shedding are widely used in power systems. These methods utilize either the steady state model or a simplified dynamic model to represent a power systems. In this dissertation, a general optimal load shedding method that considers both the dynamic process and load distribution is proposed. The unfavorable load shedding is then formulated as an optimization problem with the objective function of cost minimization. This objective function is subjected to system, security, and operation constraints. The entire problem becomes a question of optimization with differential and nonlinear equations as constraints. To solve this problem, discretization is used to change the differential equations into algebraic equations. The original problem is thus reformulated as an optimization problem and can be solved by a standard mathematical program. The general idea is then applied to traditional power systems, deregulated power systems, power systems with distributed generation, and load restoration. In the traditional power system, the method shows that governor action, generation dynamic, disturbance location, and economic factors can be taken into consideration. In the deregulated power system, two power market models are developed and incorporated into the load shedding scheme. In power systems with multiple distributed generations, the different cases of disturbances are analyzed and models of different distributed generation developed. The general idea is then applied. Finally, the load restoration problem is studied, and it is proposed that an optimization method be applied to it. This dissertation provides a comprehensive solution for load shedding problem in power systems. The models developed in this research can also be used to study other power system problems.

  11. Photochemical approaches to vision restoration

    PubMed Central

    Van Gelder, Russell N.

    2015-01-01

    Photoswitches are traditional pharmacologic agonists, antagonists, or channel blockers that are covalently modified with an azobenzene derivative. Azobenzene undergoes wavelength-dependent isomerization between cis and trans conformation. For some photoswitches, only one of these configurations is biologically active, resulting in light-dependent activation or inhibition of function. Photoswitches that feature a quaternary ammonium coupled to the azobenzene moiety cause light-dependent neuronal depolarization due to blockage of voltage-gated potassium channels. Two photoswitch strategies have been pursued. In the one-component strategy, the photoswitch is applied to native receptors; in the two-component strategy, the photoswitch is combined with virally-mediated expression of a genetically modified receptor, to which the photoswitch may covalently bind. The former approach is simpler but the latter allows precise anatomic targeting of photoswitch activity. Acrylamide-azobenzene-quaternary ammonium (AAQ) is the prototypical first-generation one-component photoswitch. When applied to retinas with outer retinal degeneration, ganglion cell firing occurs in response to blue light, and is abrogated by green light. In vivo, AAQ restored pupillary light responses and behavioral light responses in blind animals. DENAQ is a prototypical second generation one-component photoswitch. It features spontaneous thermal relaxation so cell firing ceases in dark, and features a red-shifted activation spectrum. Interestingly, DENAQ only photoswitches in retinas with outer retinal degeneration. MAG is a photoswitched glutamate analog which covalently binds to a modified ionotropic glutamate receptor, LiGluR. When applied together, MAG and LiGluR also rescue physiologic and behavioral light responses in blind mice. Together, photoswitch compounds offer a potentially useful approach to restoration of vision in outer retinal degeneration. PMID:25680758

  12. Chemical Chaperones Reduce ER Stress and Restore Glucose Homeostasis in a Mouse Model of Type 2 Diabetes

    NASA Astrophysics Data System (ADS)

    Özcan, Umut; Yilmaz, Erkan; Özcan, Lale; Furuhashi, Masato; Vaillancourt, Eric; Smith, Ross O.; Görgün, Cem Z.; Hotamisligil, Gökhan S.

    2006-08-01

    Endoplasmic reticulum (ER) stress is a key link between obesity, insulin resistance, and type 2 diabetes. Here, we provide evidence that this mechanistic link can be exploited for therapeutic purposes with orally active chemical chaperones. 4-Phenyl butyric acid and taurine-conjugated ursodeoxycholic acid alleviated ER stress in cells and whole animals. Treatment of obese and diabetic mice with these compounds resulted in normalization of hyperglycemia, restoration of systemic insulin sensitivity, resolution of fatty liver disease, and enhancement of insulin action in liver, muscle, and adipose tissues. Our results demonstrate that chemical chaperones enhance the adaptive capacity of the ER and act as potent antidiabetic modalities with potential application in the treatment of type 2 diabetes.

  13. Restorative Mediation: The Application of Restorative Justice Practice and Philosophy to Clergy Sexual Abuse Cases

    ERIC Educational Resources Information Center

    Noll, Douglas E.; Harvey, Linda

    2008-01-01

    This article will present the restorative justice model and examine how the restorative justice philosophy and process can be applied to clergy-perpetrated sexual abuse and religious sexual misconduct to resolve legal claims and allow the process of healing to begin. Restorative justice is a holistic approach to criminal, civil, and church law…

  14. 75 FR 34975 - Notice of Estuary Habitat Restoration Council's Intent to Revise its Estuary Habitat Restoration...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-21

    ... the Final Estuary Habitat Restoration Strategy (67 FR 71942). Section 106(f) of the Act authorizes the... National Oceanic and Atmospheric Administration RIN 0648-XX00 Notice of Estuary Habitat Restoration Council's Intent to Revise its Estuary Habitat Restoration Strategy; Request for Public Comment...

  15. 15 CFR 990.55 - Restoration selection-developing restoration plans.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Restoration selection-developing restoration plans. 990.55 Section 990.55 Commerce and Foreign Trade Regulations Relating to Commerce and... POLLUTION ACT REGULATIONS NATURAL RESOURCE DAMAGE ASSESSMENTS Restoration Planning Phase §...

  16. 15 CFR 990.55 - Restoration selection-developing restoration plans.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Restoration selection-developing restoration plans. 990.55 Section 990.55 Commerce and Foreign Trade Regulations Relating to Commerce and... POLLUTION ACT REGULATIONS NATURAL RESOURCE DAMAGE ASSESSMENTS Restoration Planning Phase §...

  17. 15 CFR 990.53 - Restoration selection-developing restoration alternatives.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Restoration selection-developing restoration alternatives. 990.53 Section 990.53 Commerce and Foreign Trade Regulations Relating to Commerce... OIL POLLUTION ACT REGULATIONS NATURAL RESOURCE DAMAGE ASSESSMENTS Restoration Planning Phase §...

  18. 15 CFR 990.53 - Restoration selection-developing restoration alternatives.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Restoration selection-developing restoration alternatives. 990.53 Section 990.53 Commerce and Foreign Trade Regulations Relating to Commerce... OIL POLLUTION ACT REGULATIONS NATURAL RESOURCE DAMAGE ASSESSMENTS Restoration Planning Phase §...

  19. 15 CFR 990.53 - Restoration selection-developing restoration alternatives.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 3 2012-01-01 2012-01-01 false Restoration selection-developing restoration alternatives. 990.53 Section 990.53 Commerce and Foreign Trade Regulations Relating to Commerce... OIL POLLUTION ACT REGULATIONS NATURAL RESOURCE DAMAGE ASSESSMENTS Restoration Planning Phase §...

  20. 15 CFR 990.53 - Restoration selection-developing restoration alternatives.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 3 2013-01-01 2013-01-01 false Restoration selection-developing restoration alternatives. 990.53 Section 990.53 Commerce and Foreign Trade Regulations Relating to Commerce... OIL POLLUTION ACT REGULATIONS NATURAL RESOURCE DAMAGE ASSESSMENTS Restoration Planning Phase §...

  1. Colistin-Induced Nephrotoxicity in Mice Involves the Mitochondrial, Death Receptor, and Endoplasmic Reticulum Pathways

    PubMed Central

    Dai, Chongshan; Li, Jichang; Tang, Shusheng

    2014-01-01

    Nephrotoxicity is the dose-limiting factor for colistin, but the exact mechanism is unknown. This study aimed to investigate the roles of the mitochondrial, death receptor, and endoplasmic reticulum pathways in colistin-induced nephrotoxicity. Mice were intravenously administered 7.5 or 15 mg of colistin/kg of body weight/day (via a 3-min infusion and divided into two doses) for 7 days. Renal function, oxidative stress, and apoptosis were measured. Representative biomarkers involved in the mitochondrial, death receptor, and endoplasmic reticulum pathways were investigated, and the key markers involved in apoptosis and autophagy were examined. After 7-day colistin treatment, significant increase was observed with blood urea nitrogen, serum creatinine, and malondialdehyde, while activities of superoxide dismutase (SOD) and catalase decreased in the kidneys. Acute tubular necrosis and mitochondrial dysfunction were detected, and colistin-induced apoptosis was characterized by DNA fragmentation, cleavage of poly(ADP-ribose) polymerase (PARP-1), increase of 8-hydroxydeoxyguanosine (8-OHdG), and activation of caspases (caspase-8, -9, and -3). It was evident that colistin-induced apoptosis involved the mitochondrial pathway (downregulation of Bcl-2 and upregulation of cytochrome C [cytC] and Bax), death receptor pathway (upregulation of Fas, FasL, and Fas-associated death domain [FADD]), and endoplasmic reticulum pathway (upregulation of Grp78/Bip, ATF6, GADD153/CHOP, and caspase-12). In the 15-mg/kg/day colistin group, expression of the cyclin-dependent kinase 2 (CDK2) and phosphorylated JNK (p-JNK) significantly increased (P < 0.05), while in the 7.5-mg/kg/day colistin group, a large number of autophagolysosomes and classic autophagy were observed. Western blot results of Beclin-1 and LC3B indicated that autophagy may play a protective role in colistin-induced nephrotoxicity. In conclusion, this is the first study to demonstrate that all three major apoptosis pathways

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

    PubMed

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

    2015-12-16

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

  3. Electro-optical imaging of F-actin and endoplasmic reticulum in living and fixed plant cells.

    PubMed

    Allen, N S; Bennett, M N

    1996-01-01

    Confocal and video micrographs of living and fixed alfalfa roots, onion epithelial and pear pollen cells illustrate the architecture of the cytoskeleton and endoplasmic reticulum in plant cells. Fixation of plant tissues to preserve cytoplasmic structure poses special problems. When possible, emphasis should be placed on the imaging of structures in stained living cells over time. The early events that occur when Nod factors or bacteria elicit nodule formation in alfalfa roots will illustrate several approaches to plant cell fixation, staining and imaging. The first observable events after Nod factor stimulation occur in root hairs and are changes in rates of cytoplasmic streaming, nuclear movements, and changes in the shape of the vacuole. Within ten minutes, the endoplasmic reticulum shifts position towards the tip of the root hair. For comparison, the endoplasmic reticulum localization in pollen tubes and onion epithelial cells will be illustrated. The actin cytoskeleton undergoes a series of changes over a twelve hour period. These changes in the cytoskeleton are spatially and temporally correlated with the observed growth changes of the root hairs. This dynamic change of the actin filament and endoplasmic reticulum and associated secretory vesicles in these root hairs suggests a mechanism for the observed root hair growth changes. PMID:9601538

  4. The Teacher's Guide to Restorative Classroom Discipline

    ERIC Educational Resources Information Center

    Meyer, Luanna H.; Evans, Ian M.

    2012-01-01

    With restorative discipline, schools move beyond punitive approaches to shared expectations for learning and behavior. Used together with "The School Leader's Guide to Restorative Discipline," this teacher's guide shows how to create a welcoming and responsible community within your classroom, contributing to a consistent, schoolwide approach to…

  5. Soil inoculation steers restoration of terrestrial ecosystems.

    PubMed

    Wubs, E R Jasper; van der Putten, Wim H; Bosch, Machiel; Bezemer, T Martijn

    2016-01-01

    Many natural ecosystems have been degraded because of human activities(1,2) and need to be restored so that biodiversity is protected. However, restoration can take decades and restoration activities are often unsuccessful(3) because of abiotic constraints (for example, eutrophication, acidification) and unfavourable biotic conditions (for example, competition or adverse soil community composition). A key question is what manageable factors prevent transition from degraded to restored ecosystems and what interventions are required for successful restoration(2,4). Experiments have shown that the soil community is an important driver of plant community development(5-8), suggesting that manipulation of the soil community is key to successful restoration of terrestrial ecosystems(3,9). Here we examine a large-scale, six-year-old field experiment on ex-arable land and show that application of soil inocula not only promotes ecosystem restoration, but that different origins of soil inocula can steer the plant community development towards different target communities, varying from grassland to heathland vegetation. The impact of soil inoculation on plant and soil community composition was most pronounced when the topsoil layer was removed, whereas effects were less strong, but still significant, when the soil inocula were introduced into intact topsoil. Therefore, soil inoculation is a powerful tool to both restore disturbed terrestrial ecosystems and steer plant community development. PMID:27398907

  6. Restoring primary anterior teeth: updated for 2014.

    PubMed

    Waggoner, William F

    2015-01-01

    The purpose of this paper was to review the current literature associated with the techniques and materials for the restoration of primary anterior teeth and make clinical recommendations based upon the available literature. A variety of esthetic restorative materials are available to utilize for restoring primary incisors. Awareness of the specific strengths, weakness, and properties of each material can enhance the clinician's ability to make the best choice of selection for each individual situation. Intracoronal restorations of primary teeth may utilize resin composites, glass ionomer cements, resin-modified ionomers, or polyacid-modified resins. Full coronal restoration of primary incisors may be indicated for a number of reasons. Crowns available for restoration of primary incisors include those that are directly bonded onto the tooth, which generally are a resin material, and crowns that are luted onto the tooth and are either some type of stainless steel or zirconia crown. There is insufficient controlled, clinical data to suggest that one type of restoration is superior to another. Operator preferences, esthetic demands by parents, the child's behavior, the amount of tooth structure remaining, and moisture and hemorrhage control are all variables that affect the decision and ultimate outcome of whatever restorative solution is chosen. PMID:25905657

  7. WoonyBird Restoration Plant Selector Manual

    EPA Science Inventory

    Modifying greenspaces to enhance habitat value has been proposed as a means towards protecting or restoring biodiversity in urban landscapes. As part of a framework for developing low-cost, low-impact enhancements that can be incorporated during the restoration of greenspaces to ...

  8. Soil inoculation steers restoration of terrestrial ecosystems.

    PubMed

    Wubs, E R Jasper; van der Putten, Wim H; Bosch, Machiel; Bezemer, T Martijn

    2016-07-11

    Many natural ecosystems have been degraded because of human activities(1,2) and need to be restored so that biodiversity is protected. However, restoration can take decades and restoration activities are often unsuccessful(3) because of abiotic constraints (for example, eutrophication, acidification) and unfavourable biotic conditions (for example, competition or adverse soil community composition). A key question is what manageable factors prevent transition from degraded to restored ecosystems and what interventions are required for successful restoration(2,4). Experiments have shown that the soil community is an important driver of plant community development(5-8), suggesting that manipulation of the soil community is key to successful restoration of terrestrial ecosystems(3,9). Here we examine a large-scale, six-year-old field experiment on ex-arable land and show that application of soil inocula not only promotes ecosystem restoration, but that different origins of soil inocula can steer the plant community development towards different target communities, varying from grassland to heathland vegetation. The impact of soil inoculation on plant and soil community composition was most pronounced when the topsoil layer was removed, whereas effects were less strong, but still significant, when the soil inocula were introduced into intact topsoil. Therefore, soil inoculation is a powerful tool to both restore disturbed terrestrial ecosystems and steer plant community development.

  9. Restorative Justice: A Changing Community Response

    ERIC Educational Resources Information Center

    Ryan, Thomas G.; Ruddy, Sean

    2015-01-01

    Our purpose herein is to demonstrate how restorative justice continues to unfold globally and we explain how the use of a restorative justice ideology and intervention leads to a common alternative, not only in criminal justice institutions, but also within social agencies, such as elementary schools, and the related social support systems. We…

  10. 77 FR 56749 - Gulf Coast Ecosystem Restoration

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-13

    ... HOUSE, Washington, September 10, 2012. [FR Doc. 2012-22807 Filed 9-12-12; 11:15 am] Billing code 3295-F2... Documents#0;#0; ] Executive Order 13626 of September 10, 2012 Gulf Coast Ecosystem Restoration By the..., Executive Order 13554 established a Gulf Coast Ecosystem Restoration Task Force (Task Force) to...

  11. Ecological Restoration: Bringing Back the Prairie.

    ERIC Educational Resources Information Center

    Murray, Molly Fifield

    1997-01-01

    Defines ecological restoration and offers a plan for prairie restoration as a schoolyard project. Steps include researching and planning the site, preparation and planting, and continuing management of the site. Ecological concepts in this activity also relate to science, language arts, math, social studies, art, and music for K-12 students. (AIM)

  12. Hearing Restoration in Neurofibromatosis Type II Patients

    PubMed Central

    Lee, Jeon Mi; Chang, Jin Woo; Choi, Jae Young

    2016-01-01

    Patients with neurofibromatosis type II will eventually succumb to bilateral deafness. For patients with hearing loss, modern medical science technology can provide efficient hearing restoration through a number of various methods. In this article, several hearing restoration methods for patients with neurofibromatosis type II are introduced. PMID:27189272

  13. ASSESSING THE EFFECTIVENESS OF RESTORATION TECHNOLOGIES

    EPA Science Inventory

    Numerous stream and riparian restoration projects are being undertaken across the nation at a variety of scales and for disparate reasons. Unfortunately, there are very few studies associated with these restoration efforts which provide a consistent and practical methodology to e...

  14. Changing trends in hair restoration surgery.

    PubMed

    Venkataram, Mysore

    2006-01-01

    Androgenetic alopecia is an important and common cause for baldness. Despite recent advances, the drug therapy of this condition remains unsatisfactory. Surgical hair restoration is the only permanent method of treating this condition. Introduction of recent techniques such as follicular unit transplantation have improved the cosmetic results and patient satisfaction. This article discusses the latest trends in hair restoration surgery. PMID:16707815

  15. The effect of occlusal forces on restorations.

    PubMed

    Larson, Thomas D

    2014-09-01

    This review will focus on the effect occlusal forces, both normal masticatory force and paranormal bruxing and clenching force, have on various restorative materials and their interaction with the teeth through a variety of bonding mechanisms. Salient physical properties of each of the materials will be reviewed, as well as the effect occlusal force has on restoration durability.

  16. Amalgam Restorations: To Bond or Not.

    PubMed

    Larson, Thomas D

    2015-01-01

    This article will review the use of various liners used to eliminate microleakage in amalgam restorations. It will review the literature about whether amalgam restorations are improved by using a bonding process and if so specifically how it improves the patient outcome.

  17. Cell density and growth-dependent down-regulation of both intracellular calcium responses to agonist stimuli and expression of smooth-surfaced endoplasmic reticulum in MC3T3-E1 osteoblast-like cells.

    PubMed

    Koizumi, Toshiyuki; Hikiji, Hisako; Shin, Wee Soo; Takato, Tsuyoshi; Fukuda, Satoru; Abe, Takahiro; Koshikiya, Noboru; Iwasawa, Kuniaki; Toyo-oka, Teruhiko

    2003-02-21

    A two-dimensional intracellular Ca(2+) ([Ca(2+)](i)) imaging system was used to examine the relationship between [Ca(2+)](i) handling and the proliferation of MC3T3-E1 osteoblast-like cells. The resting [Ca(2+)](i) level in densely cultured cells was 1.5 times higher than the [Ca(2+)](i) level in sparsely cultured cells or in other cell types (mouse fibroblasts, rat vascular smooth muscle cells, and bovine endothelial cells). A high resting [Ca(2+)](i) level may be specific for MC3T3-E1 cells. MC3T3-E1 cells were stimulated with ATP (10 microM), caffeine (10 mM), thapsigargin (1 microM), or ionomycin (10 microM), and the effect on the [Ca(2+)](i) level of MC3T3-E1 cells was studied. The percentage of responding cells and the degree of [Ca(2+)](i) elevation were high in the sparsely cultured cells and low in densely cultured cells. The rank order for the percentage of responding cells and magnitude of the Ca(2+) response to the stimuli was ionomycin > thapsigargin = ATP > caffeine and suggests the existence of differences among the various [Ca(2+)](i) channels. All Ca(2+) responses in the sparsely cultured MC3T3-E1 cells, unlike in other cell types, disappeared after the cells reached confluence. Heptanol treatment of densely cultured cells restored the Ca(2+) response, suggesting that cell-cell contact is involved with the confluence-dependent disappearance of the Ca(2+) response. Immunohistological analysis of type 1 inositol trisphosphate receptors and electron microscopy showed distinct expression of inositol trisphosphate receptor proteins and smooth-surfaced endoplasmic reticulum in sparsely cultured cells but reduced levels in densely cultured cells. These results indicate that the underlying basis of confluence-dependent [Ca(2+)](i) regulation is down-regulation of smooth-surfaced endoplasmic reticulum by cell-cell contacts.

  18. Maintaining professional resilience through group restorative supervision.

    PubMed

    Wallbank, Sonya

    2013-08-01

    Restorative clinical supervision has been delivered to over 2,500 professionals and has shown to be highly effective in reducing burnout, stress and increasing compassion satisfaction. Demand for the programme has shown that a sustainable model of implementation is needed for organisations who may not be able to invest in continued individual sessions. Following the initial six sessions, group restorative supervision has been developed and this paper reports on the programme's success in maintaining and continuing to improve compassion satisfaction, stress and burnout through the process of restorative group supervision. This means that organisations can continue to maintain the programme once the initial training has been completed and have confidence within the restorative group supervision to support professionals in managing the emotional demands of their role. The restorative groups have also had inadvertent positive benefits in workplace functioning. The paper outlines how professionals have been able to use this learning to support them in being more effective. PMID:23986988

  19. Hepatoprotective Effect of Quercetin on Endoplasmic Reticulum Stress and Inflammation after Intense Exercise in Mice through Phosphoinositide 3-Kinase and Nuclear Factor-Kappa B.

    PubMed

    Tang, Yuhan; Li, Juan; Gao, Chao; Xu, Yanyan; Li, Yanyan; Yu, Xiao; Wang, Jing; Liu, Liegang; Yao, Ping

    2016-01-01

    The mechanisms underlying intense exercise-induced liver damage and its potential treatments remain unclear. We explored the hepatoprotection and mechanisms of quercetin, a naturally occurring flavonoid, in strenuous exercise-derived endoplasmic reticulum stress (ERS) and inflammation. Intense exercise (28 m/min at a 5° slope for 90 min) resulted in the leakage of aminotransferases in the BALB/C mice. The hepatic ultrastructural malformations and oxidative stress levels were attenuated by quercetin (100 mg/kg·bw). Intense exercise and thapsigargin- (Tg-) induced ERS (glucose-regulated protein 78, GRP78) and inflammatory cytokines levels (IL-6 and TNF-α) were decreased with quercetin. Furthermore, quercetin resulted in phosphoinositide 3-kinase (PI3K) induction, Ca(2+) restoration, and blockade of the activities of Jun N-terminal kinase (JNK), activating transcription factor 6 (ATF6) and especially NF-κB (p65 and p50 nuclear translocation). A PI3K inhibitor abrogated the protection of quercetin on ERS and inflammation of mouse hepatocytes. SP600125 (JNK inhibitor), AEBSF (ATF6 inhibitor), and especially PDTC (NF-κB inhibitor) enhanced the quercetin-induced protection against Tg stimulation. Collectively, intense exercise-induced ERS and inflammation were attenuated by quercetin. PI3K/Akt activation and JNK, ATF6, and especially NF-κB suppression were involved in the protection. Our results highlight a novel preventive strategy for treating ERS and inflammation-mediated liver damage induced by intense exercise using natural phytochemicals. PMID:27504150

  20. Intermedin1-53 attenuates vascular smooth muscle cell calcification by inhibiting endoplasmic reticulum stress via cyclic adenosine monophosphate/protein kinase A pathway.

    PubMed

    Chang, Jin-Rui; Duan, Xiao-Hui; Zhang, Bao-Hong; Teng, Xu; Zhou, Ye-Bo; Liu, Yue; Yu, Yan-Rong; Zhu, Yi; Tang, Chao-Shu; Qi, Yong-Fen

    2013-10-01

    We previously reported that endoplasmic reticulum (ER) stress-mediated apoptosis participated in vascular calcification. Importantly, a novel paracrine/autocrine peptide intermedin1-53 (IMD1-53) in the vasculature inhibited vascular calcification in rats. But the mechanisms needed to be fully elucidated. Vascular smooth muscle cells (VSMCs) calcification was induced by CaCl2 and β-glycerophosphate. Tunicamycin (Tm) or dithiothreitol (DTT) was used to induce ER stress. We found that IMD1-53 (10(-7)mol/L) treatment significantly alleviated the protein expression of ER stress hallmarks activating transcription factor 4 (ATF4), ATF6, glucose-regulated protein 78 (GRP78) and GRP94 induced by Tm or DTT. ER stress occurred in early and late calcification of VSMCs but was inhibited by IMD1-53. These inhibitory effects of IMD1-53 were abolished by treatment with the protein kinase A (PKA) inhibitor H89. Pretreatment with IMD1-53 decreased the number of apoptotic VSMCs and downregulated protein expression of cleaved caspase 12 and C/EBP homologous protein (CHOP) in calcified VSMCs. Concurrently, IMD1-53 restored the loss of VSMC lineage markers and ameliorated calcium deposition and alkaline phosphatase activity in calcified VSMCs as well. The observation was further verified by Alizarin Red S staining, which showed that IMD1-53 reduced positive red nodules among calcified VSMCs. In conclusion, IMD1-53 attenuated VSMC calcification by inhibiting ER stress through cAMP/PKA signalling.

  1. Protective effect of S-allyl-L-cysteine against endoplasmic reticulum stress-induced neuronal death is mediated by inhibition of calpain.

    PubMed

    Imai, Toru; Kosuge, Yasuhiro; Endo-Umeda, Kaori; Miyagishi, Hiroko; Ishige, Kumiko; Makishima, Makoto; Ito, Yoshihisa

    2014-02-01

    Endoplasmic reticulum (ER) stress, implicated in various neurodegenerative processes, increases the level of intracellular Ca(2+) and leads to activation of calpain, a Ca(2+)-dependent cysteine protease. We have shown previously that S-allyl-L-cysteine (SAC) in aged garlic extracts significantly protects cultured rat hippocampal neurons (HPNs) against ER stress-induced neurotoxicity. The neuroprotective effect of SAC was compared with those of the related antioxidant compounds, L-cysteine (CYS) and N-acetylcysteine (NAC), on calpain activity in HPNs and also in vitro. SAC, but not CYS or NAC, reversibly restored the survival of HPNs and increased the degradation of α-spectrin, a substrate for calpain, induced by tunicamycin, a typical ER stress inducer. Activities of μ- and m-calpains in vitro were also concentration dependently suppressed by SAC, but not by CYS or NAC. At submaximal concentration, although ALLN (5 pM), which blocks the active site of calpain, and calpastatin (100 pM), an endogenous calpain-inhibitor protein, additively inhibited μ-calpain activity in vitro in combination with SAC, the effect of PD150606 (25 μM), which prevents interaction of Ca(2+) with the Ca(2+)-binding site of calpain, was unaffected by SAC. In contrast, SAC (1 mM) significantly reversed the effect of PD150606 at a concentration that elicited supramaximal inhibition (100 μM), but did not affect ALLN (1 nM)- and calpastatin (100 nM)-induced inhibition of μ-calpain activity. These results suggest that the protective effects of SAC against ER stress-induced neuronal cell death are not attributable to antioxidant activity, but to suppression of calpain through interaction with its Ca(2+)-binding site. PMID:24287800

  2. Combined NADPH oxidase 1 and interleukin 10 deficiency induces chronic endoplasmic reticulum stress and causes ulcerative colitis-like disease in mice.

    PubMed

    Tréton, Xavier; Pedruzzi, Eric; Guichard, Cécile; Ladeiro, Yannick; Sedghi, Shirin; Vallée, Mélissa; Fernandez, Neike; Bruyère, Emilie; Woerther, Paul-Louis; Ducroc, Robert; Montcuquet, Nicolas; Freund, Jean-Noel; Van Seuningen, Isabelle; Barreau, Frédérick; Marah, Assiya; Hugot, Jean-Pierre; Cazals-Hatem, Dominique; Bouhnik, Yoram; Daniel, Fanny; Ogier-Denis, Eric

    2014-01-01

    Ulcerative colitis (UC) is a chronic inflammatory bowel disease affecting the rectum which progressively extents. Its etiology remains unknown and the number of treatments available is limited. Studies of UC patients have identified an unbalanced endoplasmic reticulum (ER) stress in the non-inflamed colonic mucosa. Animal models with impaired ER stress are sensitive to intestinal inflammation, suggesting that an unbalanced ER stress could cause inflammation. However, there are no ER stress-regulating strategies proposed in the management of UC partly because of the lack of relevant preclinical model mimicking the disease. Here we generated the IL10/Nox1dKO mouse model which combines immune dysfunction (IL-10 deficiency) and abnormal epithelium (NADPH oxidase 1 (Nox1) deficiency) and spontaneously develops a UC-like phenotype with similar complications (colorectal cancer) than UC. Our data identified an unanticipated combined role of IL10 and Nox1 in the fine-tuning of ER stress responses in goblet cells. As in humans, the ER stress was unbalanced in mice with decreased eIF2α phosphorylation preceding inflammation. In IL10/Nox1dKO mice, salubrinal preserved eIF2α phosphorylation through inhibition of the regulatory subunit of the protein phosphatase 1 PP1R15A/GADD34 and prevented colitis. Thus, this new experimental model highlighted the central role of epithelial ER stress abnormalities in the development of colitis and defined the defective eIF2α pathway as a key pathophysiological target for UC. Therefore, specific regulators able to restore the defective eIF2α pathway could lead to the molecular remission needed to treat UC. PMID:25014110

  3. ROS-mediated endoplasmic reticulum stress and mitochondrial dysfunction underlie apoptosis induced by resveratrol and arsenic trioxide in A549 cells.

    PubMed

    Gu, Shiyan; Chen, Chengzhi; Jiang, Xuejun; Zhang, Zunzhen

    2016-02-01

    Although it is well documented that endoplasmic reticulum (ER) stress and mitochondrial dysfunction are associated with apoptosis, little is known about whether they are involved in the apoptotic cell death induced by resveratrol and arsenic trioxide (ATO) combination. In this study, we identified a series of sensitization effects of resveratrol on human lung adenocarcinoma A549 cells to ATO treatment, with the combination index (CI) of resveratrol and ATO less than 1. Then, we demonstrated that ER stress was contributed to this synergistic effect, which was manifested by increased the expression levels of ER stress hallmarks, including 78-kDa glucose-regulated protein (GRP 78), caspase 12 and C/EBP-homologous protein (CHOP), In addition, mitochondrial dysfunction was observed after exposure of A549 cells to resveratrol or/and ATO, which was displayed by some alterations of mitochondria-related events, such as loss of mitochondrial membrane potential, cytochrome c release and changes of Bax and Bcl-2 expressions. Our results further demonstrated that resveratrol and ATO-induced ER stress and mitochondrial dysfunction were mediated by reactive oxygen species (ROS), showing that pre-treatment of N-acetyl-l-cysteine, a potent ROS scavenger, restored the ER stress and mitochondrial dysfunction in cells co-treated with resveratrol and ATO, thereby leading to the reduction of the apoptosis. Collectively, these results clearly suggest that ROS-mediated ER stress and mitochondrial dysfunction were involved in the apoptosis induced by resveratrol and ATO in A549 cells, which provides a novel insight into the molecular mechanisms of resveratrol-mediated ATO-sensitization.

  4. Hepatoprotective Effect of Quercetin on Endoplasmic Reticulum Stress and Inflammation after Intense Exercise in Mice through Phosphoinositide 3-Kinase and Nuclear Factor-Kappa B

    PubMed Central

    Tang, Yuhan; Li, Juan; Gao, Chao; Xu, Yanyan; Li, Yanyan; Yu, Xiao; Wang, Jing; Liu, Liegang

    2016-01-01

    The mechanisms underlying intense exercise-induced liver damage and its potential treatments remain unclear. We explored the hepatoprotection and mechanisms of quercetin, a naturally occurring flavonoid, in strenuous exercise-derived endoplasmic reticulum stress (ERS) and inflammation. Intense exercise (28 m/min at a 5° slope for 90 min) resulted in the leakage of aminotransferases in the BALB/C mice. The hepatic ultrastructural malformations and oxidative stress levels were attenuated by quercetin (100 mg/kg·bw). Intense exercise and thapsigargin- (Tg-) induced ERS (glucose-regulated protein 78, GRP78) and inflammatory cytokines levels (IL-6 and TNF-α) were decreased with quercetin. Furthermore, quercetin resulted in phosphoinositide 3-kinase (PI3K) induction, Ca2+ restoration, and blockade of the activities of Jun N-terminal kinase (JNK), activating transcription factor 6 (ATF6) and especially NF-κB (p65 and p50 nuclear translocation). A PI3K inhibitor abrogated the protection of quercetin on ERS and inflammation of mouse hepatocytes. SP600125 (JNK inhibitor), AEBSF (ATF6 inhibitor), and especially PDTC (NF-κB inhibitor) enhanced the quercetin-induced protection against Tg stimulation. Collectively, intense exercise-induced ERS and inflammation were attenuated by quercetin. PI3K/Akt activation and JNK, ATF6, and especially NF-κB suppression were involved in the protection. Our results highlight a novel preventive strategy for treating ERS and inflammation-mediated liver damage induced by intense exercise using natural phytochemicals. PMID:27504150

  5. The molecular mechanism of endoplasmic reticulum stress-induced apoptosis in PC-12 neuronal cells: the protective effect of insulin-like growth factor I.

    PubMed

    Zou, Cheng-Gang; Cao, Xiu-Zhen; Zhao, Yue-Shui; Gao, Shun-Yu; Li, Shu-De; Liu, Xian-Yong; Zhang, Yan; Zhang, Ke-Qin

    2009-01-01

    Endoplasmic reticulum (ER) stress has been implicated in several neurodegenerative diseases. Although CCAAT/enhancer-binding protein homologous protein (CHOP) has been shown to play a critical role in ER stress, the precise apoptosis cascade downstream of CHOP is unknown. In this report, we investigated the mechanism of ER stress-mediated apoptosis as well as the action of IGF-I in PC-12 neuronal cells. Our results demonstrated that tribbles-related protein 3 (TRB3), which is a target gene of CHOP, was responsible for tunicamycin (an ER stress inducer)-induced apoptosis. TRB3 could promote dephosphorylation of Akt in PC-12 cells. IGF-I inhibited ER stress-induced apoptosis by restoring the phosphorylation level of Akt. Both wortmannin (a phosphatidylinositide 3-kinase inhibitor) and SB 212090 (a p38 MAPK inhibitor) suppressed the protective effect of IGF-I on ER stress-induced apoptosis. Interestingly, IGF-I attenuated ER stress-mediated expression of TRB3 but not CHOP. This action of IGF-I was abolished by SB 212090 but not by wortmannin. Immunoprecipitation analysis revealed that IGF-I promoted the phosphorylation of CHOP by activating p38 MAPK, probably leading to a decrease in the transcriptional activity of CHOP. The dephosphorylation of Akt resulted in increased expression of a proapoptotic protein, p53 up-regulated modulator of apoptosis (PUMA), in a forkhead box O3a-dependent manner. Knockdown of PUMA by short hairpin RNA attenuated ER stress-mediated apoptosis. Thus, our current study indicates that both TRB3 and PUMA are critical molecules in ER stress-induced apoptosis. IGF-I effectively protects PC-12 neuronal cells against ER stress-induced apoptosis through the phosphatidylinositide 3-kinase/Akt and p38 MAPK pathways.

  6. Crown lengthening surgery: a restorative-driven periodontal procedure.

    PubMed

    Levine, D F; Handelsman, M; Ravon, N A

    1999-02-01

    Improper management of the periodontal tissues during restorative procedures is a common, but often overlooked, cause of failure. When a restoration is placed, the preservation of an intact, healthy periodontium is necessary to maintain the tooth or teeth being restored. Predictable long-term restorative success requires a combination of restorative principles with the correct management of the periodontal tissues.

  7. 12 CFR 1229.11 - Capital restoration plans.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... capital restoration plan submitted by a Bank shall set forth a plan to restore its permanent and total... restoration plan, including setting forth a schedule for it to restore its permanent and total capital to... submission. A Bank must submit a proposed capital restoration plan no later than 15 business-days after...

  8. 32 CFR 644.454 - Negotiating restoration settlements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 4 2011-07-01 2011-07-01 false Negotiating restoration settlements. 644.454... Negotiating restoration settlements. Negotiated settlements in lieu of performance of actual restoration work... restoration. In view of the limitations of the Government's restoration obligations to amounts not in...

  9. 32 CFR 644.454 - Negotiating restoration settlements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Negotiating restoration settlements. 644.454... Negotiating restoration settlements. Negotiated settlements in lieu of performance of actual restoration work... restoration. In view of the limitations of the Government's restoration obligations to amounts not in...

  10. The land value impacts of wetland restoration.

    PubMed

    Kaza, Nikhil; BenDor, Todd K

    2013-09-30

    U.S. regulations require offsets for aquatic ecosystems damaged during land development, often through restoration of alternative resources. What effect does large-scale wetland and stream restoration have on surrounding land values? Restoration effects on real estate values have substantial implications for protecting resources, increasing tax base, and improving environmental policies. Our analysis focuses on the three-county Raleigh-Durham-Chapel Hill, North Carolina region, which has experienced rapid development and extensive aquatic ecological restoration (through the state's Ecosystem Enhancement Program [EEP]). Since restoration sites are not randomly distributed across space, we used a genetic algorithm to match parcels near restoration sites with comparable control parcels. Similar to propensity score analysis, this technique facilitates statistical comparison and isolates the effects of restoration sites on surrounding real estate values. Compared to parcels not proximate to any aquatic resources, we find that, 1) natural aquatic systems steadily and significantly increase parcel values up to 0.75 mi away, and 2) parcels <0.5 mi from EEP restoration sites have significantly lower sale prices, while 3) parcels >0.5 mi from EEP sites gain substantial amenity value. When we control for intervening water bodies (e.g. un-restored streams and wetlands), we find a similar inflection point whereby parcels <0.5 mi from EEP sites exhibit lower values, and sites 0.5-0.75 mi away exhibit increased values. Our work points to the need for higher public visibility of aquatic ecosystem restoration programs and increased public information about their value. PMID:23792789

  11. The land value impacts of wetland restoration.

    PubMed

    Kaza, Nikhil; BenDor, Todd K

    2013-09-30

    U.S. regulations require offsets for aquatic ecosystems damaged during land development, often through restoration of alternative resources. What effect does large-scale wetland and stream restoration have on surrounding land values? Restoration effects on real estate values have substantial implications for protecting resources, increasing tax base, and improving environmental policies. Our analysis focuses on the three-county Raleigh-Durham-Chapel Hill, North Carolina region, which has experienced rapid development and extensive aquatic ecological restoration (through the state's Ecosystem Enhancement Program [EEP]). Since restoration sites are not randomly distributed across space, we used a genetic algorithm to match parcels near restoration sites with comparable control parcels. Similar to propensity score analysis, this technique facilitates statistical comparison and isolates the effects of restoration sites on surrounding real estate values. Compared to parcels not proximate to any aquatic resources, we find that, 1) natural aquatic systems steadily and significantly increase parcel values up to 0.75 mi away, and 2) parcels <0.5 mi from EEP restoration sites have significantly lower sale prices, while 3) parcels >0.5 mi from EEP sites gain substantial amenity value. When we control for intervening water bodies (e.g. un-restored streams and wetlands), we find a similar inflection point whereby parcels <0.5 mi from EEP sites exhibit lower values, and sites 0.5-0.75 mi away exhibit increased values. Our work points to the need for higher public visibility of aquatic ecosystem restoration programs and increased public information about their value.

  12. A functional equivalent of endoplasmic reticulum and Golgi in axons for secretion of locally synthesized proteins

    PubMed Central

    Merianda, Tanuja T.; Lin, Andrew C.; Lam, Joyce S.Y.; Vuppalanchi, Deepika; Willis, Dianna E.; Karin, Norman; Holt, Christine E.; Twiss, Jeffery L.

    2013-01-01

    Subcellular localization of protein synthesis provides a means to regulate the protein composition in far reaches of a cell. This localized protein synthesis gives neuronal processes autonomy to rapidly respond to extracellular stimuli. Locally synthesized axonal proteins enable neurons to respond to guidance cues and can help to initiate regeneration after injury. Most studies of axonal mRNA translation have concentrated on cytoplasmic proteins. While ultrastructural studies suggest that axons do not have rough endoplasmic reticulum or Golgi apparatus, mRNAs for transmembrane and secreted proteins localize to axons. Here, we show that growing axons with protein synthetic activity contain ER and Golgi components needed for classical protein synthesis and secretion. Isolated axons have the capacity to traffic locally synthesized proteins into secretory pathways and inhibition of Golgi function attenuates translation-dependent axonal growth responses. Finally, the capacity for secreting locally synthesized proteins in axons appears to be increased by injury. PMID:19022387

  13. Reduction of endoplasmic reticulum stress attenuates the defects caused by Drosophila mitofusin depletion

    PubMed Central

    Debattisti, Valentina; Pendin, Diana; Ziviani, Elena; Daga, Andrea

    2014-01-01

    Ablation of the mitochondrial fusion and endoplasmic reticulum (ER)–tethering protein Mfn2 causes ER stress, but whether this is just an epiphenomenon of mitochondrial dysfunction or a contributor to the phenotypes in mitofusin (Mfn)-depleted Drosophila melanogaster is unclear. In this paper, we show that reduction of ER dysfunction ameliorates the functional and developmental defects of flies lacking the single Mfn mitochondrial assembly regulatory factor (Marf). Ubiquitous or neuron- and muscle-specific Marf ablation was lethal, altering mitochondrial and ER morphology and triggering ER stress that was conversely absent in flies lacking the fusion protein optic atrophy 1. Expression of Mfn2 and ER stress reduction in flies lacking Marf corrected ER shape, attenuating the developmental and motor defects. Thus, ER stress is a targetable pathogenetic component of the phenotypes caused by Drosophila Mfn ablation. PMID:24469638

  14. Electron probe microanalysis of calcium release and magnesium uptake by endoplasmic reticulum in bee photoreceptors.

    PubMed

    Baumann, O; Walz, B; Somlyo, A V; Somlyo, A P

    1991-02-01

    Honey bee photoreceptors contain large sacs of endoplasmic reticulum (ER) that can be located unequivocally in freeze-dried cryosections. The elemental composition of the ER was determined by electron probe x-ray microanalysis and was visualized in high-resolution x-ray maps. In the ER of dark-adapted photoreceptors, the Ca concentration was 47.5 +/- 1.1 mmol/kg (dry weight) (mean +/- SEM). During a 3-sec nonsaturating light stimulus, approximately 50% of the Ca content was released from the ER. Light stimulation also caused a highly significant increase in the Mg content of the ER; the ratio of Mg uptake to Ca released was approximately 0.7. Our results show unambiguously that the ER is the source of Ca2+ release during cell stimulation and suggest that Mg2+ can nearly balance the charge movement of Ca2+. PMID:1992466

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

    PubMed Central

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

    2015-01-01

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

  16. Taking organelles apart, putting them back together and creating new ones: lessons from the endoplasmic reticulum.

    PubMed

    Lavoie, Christine; Roy, Line; Lanoix, Joël; Taheri, Mariam; Young, Robin; Thibault, Geneviève; Farah, Carol Abi; Leclerc, Nicole; Paiement, Jacques

    2011-06-01

    The endoplasmic reticulum (ER) is a highly dynamic organelle. It is composed of four subcompartments including nuclear envelope (NE), rough ER (rER), smooth ER (sER) and transitional ER (tER). The subcompartments are interconnected, can fragment and dissociate and are able to reassemble again. They coordinate with cell function by way of protein regulators in the surrounding cytosol. The activity of the many associated molecular machines of the ER as well as the fluid nature of the limiting membrane of the ER contribute extensively to the dynamics of the ER. This review examines the properties of the ER that permit its isolation and purification and the physiological conditions that permit reconstitution both in vitro and in vivo in normal and in disease conditions.

  17. Soluble forms of polyQ-expanded huntingtin rather than large aggregates cause endoplasmic reticulum stress

    NASA Astrophysics Data System (ADS)

    Leitman, Julia; Ulrich Hartl, F.; Lederkremer, Gerardo Z.

    2013-11-01

    In Huntington’s disease, as in other neurodegenerative diseases, it was initially thought that insoluble protein aggregates are the toxic species. However, growing evidence implicates soluble oligomeric polyglutamine-expanded huntingtin in cytotoxicity. Here we show that pathogenic huntingtin inhibits endoplasmic reticulum (ER)-associated degradation and induces ER stress before its aggregation into visible inclusions. All three branches of the unfolded protein response are activated. ER stress can be compensated by overexpression of p97/VCP, suggesting its sequestration by pathogenic huntingtin as a main cause. Stress correlates with the presence of huntingtin oligomers and is independent of continual huntingtin synthesis. Stress levels, measured in striatal neurons, are stabilized but only slowly subside on huntingtin aggregation into inclusions. Our results can be explained by the constant conversion of huntingtin monomers to toxic oligomers; large aggregates sequester the former, precluding further conversion, whereas pre-existing toxic oligomers are only gradually depleted.

  18. Regulation of calcium and phosphoinositides at endoplasmic reticulum-membrane junctions.

    PubMed

    Dickson, Eamonn J; Jensen, Jill B; Hille, Bertil

    2016-04-15

    Effective cellular function requires both compartmentalization of tasks in space and time, and coordination of those efforts. The endoplasmic reticulum's (ER) expansive and ramifying structure makes it ideally suited to serve as a regulatory platform for organelle-organelle communication through membrane contacts. These contact sites consist of two membranes juxtaposed at a distance less than 30 nm that mediate the exchange of lipids and ions without the need for membrane fission or fusion, a process distinct from classical vesicular transport. Membrane contact sites are positioned by organelle-specific membrane-membrane tethering proteins and contain a growing number of additional proteins that organize information transfer to shape membrane identity. Here we briefly review the role of ER-containing membrane junctions in two important cellular functions: calcium signalling and phosphoinositide processing. PMID:27068956

  19. Role of Endoplasmic Reticulum Stress in Atherosclerosis and Diabetic Macrovascular Complications

    PubMed Central

    Chistiakov, Dmitry A.; Sobenin, Igor A.; Orekhov, Alexander N.; Bobryshev, Yuri V.

    2014-01-01

    Age-related changes in endoplasmic reticulum (ER) are associated with stress of this cell organelle. Unfolded protein response (UPR) is a normal physiological reaction of a cell in order to prevent accumulation of unfolded and misfolded proteins in the ER and improve the normal ER function. However, in pathologic conditions such as atherosclerosis, obesity, and diabetes, ER function becomes impaired, leading to the development of ER stress. In chronic ER stress, defective posttranslational protein folding results in deposits of aberrantly folded proteins in the ER and the induction of cell apoptosis mediated by UPR sensors C/EBPα-homologous protein (CHOP) and inositol requiring protein-1 (IRE1). Since ER stress and ER-induced cell death play a nonredundant role in the pathogenesis of atherosclerosis and diabetic macrovascular complications, pharmaceutical targeting of ER stress components and pathways may be beneficial in the treatment and prevention of cardiovascular pathology. PMID:25061609

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

    PubMed

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

    2016-01-01

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

  1. Electron probe microanalysis of calcium release and magnesium uptake by endoplasmic reticulum in bee photoreceptors

    SciTech Connect

    Baumann, O.; Walz, B. ); Somlyo, A.V.; Somlyo, A.P. )

    1991-02-01

    Honey bee photoreceptors contain large sacs of endoplasmic reticulum (ER) that can be located unequivocally in freeze-dried cryosections. The elemental compositon of the ER was determined by electron probe x-ray microanalysis and was visualized in high-resolution x-ray maps. In the ER of dark-adapted photoreceptors, the Ca concentration was 47.5 {plus minus} 1.1 mmol/kg (dry weight). During a 3-sec nonsaturating light stimulus, {approximately}50% of the Ca content was released from the ER. Light stimulation also caused a highly significant increase in the Mg content of the ER; the ratio of Mg uptake to Ca released was {approximately}0.7. Our results show unambiguously that the ER is the source of Ca{sup 2+} release during cell stimulation and suggest the Mg{sup 2+} can nearly balance the charge movement of Ca{sup 2+}.

  2. Dysfunctional tubular endoplasmic reticulum constitutes a pathological feature of Alzheimer's disease.

    PubMed

    Sharoar, M G; Shi, Q; Ge, Y; He, W; Hu, X; Perry, G; Zhu, X; Yan, R

    2016-09-01

    Pathological features in Alzheimer's brains include mitochondrial dysfunction and dystrophic neurites (DNs) in areas surrounding amyloid plaques. Using a mouse model that overexpresses reticulon 3 (RTN3) and spontaneously develops age-dependent hippocampal DNs, here we report that DNs contain both RTN3 and REEPs, topologically similar proteins that can shape tubular endoplasmic reticulum (ER). Importantly, ultrastructural examinations of such DNs revealed gradual accumulation of tubular ER in axonal termini, and such abnormal tubular ER inclusion is found in areas surrounding amyloid plaques in biopsy samples from Alzheimer's disease (AD) brains. Functionally, abnormally clustered tubular ER induces enhanced mitochondrial fission in the early stages of DN formation and eventual mitochondrial degeneration at later stages. Furthermore, such DNs are abrogated when RTN3 is ablated in aging and AD mouse models. Hence, abnormally clustered tubular ER can be pathogenic in brain regions: disrupting mitochondrial integrity, inducing DNs formation and impairing cognitive function in AD and aging brains.

  3. VCP and ATL1 regulate endoplasmic reticulum and protein synthesis for dendritic spine formation.

    PubMed

    Shih, Yu-Tzu; Hsueh, Yi-Ping

    2016-01-01

    Imbalanced protein homeostasis, such as excessive protein synthesis and protein aggregation, is a pathogenic hallmark of a range of neurological disorders. Here, using expression of mutant proteins, a knockdown approach and disease mutation knockin mice, we show that VCP (valosin-containing protein), together with its cofactor P47 and the endoplasmic reticulum (ER) morphology regulator ATL1 (Atlastin-1), regulates tubular ER formation and influences the efficiency of protein synthesis to control dendritic spine formation in neurons. Strengthening the significance of protein synthesis in dendritic spinogenesis, the translation blocker cyclohexamide and the mTOR inhibitor rapamycin reduce dendritic spine density, while a leucine supplement that increases protein synthesis ameliorates the dendritic spine defects caused by Vcp and Atl1 deficiencies. Because VCP and ATL1 are the causative genes of several neurodegenerative and neurodevelopmental disorders, we suggest that impaired ER formation and inefficient protein synthesis are significant in the pathogenesis of multiple neurological disorders. PMID:26984393

  4. Endoplasmic Reticulum Stress Signaling in Mammalian Oocytes and Embryos: Life in the Balance

    PubMed Central

    Latham, Keith E.

    2015-01-01

    Mammalian oocytes and embryos are exquisitely sensitive to a wide range of insults related to physical stress, chemical exposure, and exposures to adverse maternal nutrition or health status. Although cells manifest specific responses to various stressors, many of these stressors intersect at the endoplasmic reticulum, where disruptions in protein folding and production of reactive oxygen species initiate downstream signaling events. These signals modulate mRNA translation and gene transcription, leading to recovery, activation of autophagy, or with severe and prolonged stress, apoptosis. ER stress signaling has recently come to the fore as a major contributor to embryo demise. Accordingly, agents that modulate or inhibit ER stress signaling have yielded beneficial effects on embryo survival and long-term developmental potential. We review here the mechanisms of ER stress signaling, their connections to mammalian oocytes and embryos, and the promising indications that interventions in this pathway may provide new opportunities for improving mammalian reproduction and health. PMID:25805126

  5. Friend or foe: Endoplasmic reticulum protein 29 (ERp29) in epithelial cancer

    PubMed Central

    Chen, Shaohua; Zhang, Daohai

    2015-01-01

    The endoplasmic reticulum (ER) protein 29 (ERp29) is a molecular chaperone that plays a critical role in protein secretion from the ER in eukaryotic cells. Recent studies have also shown that ERp29 plays a role in cancer. It has been demonstrated that ERp29 is inversely associated with primary tumor development and functions as a tumor suppressor by inducing cell growth arrest in breast cancer. However, ERp29 has also been reported to promote epithelial cell morphogenesis, cell survival against genotoxic stress and distant metastasis. In this review, we summarize the current understanding on the biological and pathological functions of ERp29 in cancer and discuss the pivotal aspects of ERp29 as “friend or foe” in epithelial cancer. PMID:25709888

  6. A Molecular Fluorescent Probe for Targeted Visualization of Temperature at the Endoplasmic Reticulum

    NASA Astrophysics Data System (ADS)

    Arai, Satoshi; Lee, Sung-Chan; Zhai, Duanting; Suzuki, Madoka; Chang, Young Tae

    2014-10-01

    The dynamics of cellular heat production and propagation remains elusive at a subcellular level. Here we report the first small molecule fluorescent thermometer selectively targeting the endoplasmic reticulum (ER thermo yellow), with the highest sensitivity reported so far (3.9%/°C). Unlike nanoparticle thermometers, ER thermo yellow stains the target organelle evenly without the commonly encountered problem of aggregation, and successfully demonstrates the ability to monitor intracellular temperature gradients generated by external heat sources in various cell types. We further confirm the ability of ER thermo yellow to monitor heat production by intracellular Ca2+ changes in HeLa cells. Our thermometer anchored at nearly-zero distance from the ER, i.e. the heat source, allowed the detection of the heat as it readily dissipated, and revealed the dynamics of heat production in real time at a subcellular level.

  7. ER-phagy mediates selective degradation of endoplasmic reticulum independently of the core autophagy machinery

    PubMed Central

    Schuck, Sebastian; Gallagher, Ciara M.; Walter, Peter

    2014-01-01

    ABSTRACT Selective autophagy of damaged or redundant organelles is an important mechanism for maintaining cell homeostasis. We found previously that endoplasmic reticulum (ER) stress in the yeast Saccharomyces cerevisiae causes massive ER expansion and triggers the formation of large ER whorls. Here, we show that stress-induced ER whorls are selectively taken up into the vacuole, the yeast lysosome, by a process termed ER-phagy. Import into the vacuole does not involve autophagosomes but occurs through invagination of the vacuolar membrane, indicating that ER-phagy is topologically equivalent to microautophagy. Even so, ER-phagy requires neither the core autophagy machinery nor several other proteins specifically implicated in microautophagy. Thus, autophagy of ER whorls represents a distinct type of organelle-selective autophagy. Finally, we provide evidence that ER-phagy degrades excess ER membrane, suggesting that it contributes to cell homeostasis by controlling organelle size. PMID:25052096

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

    PubMed

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

    2015-01-01

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

  9. Involvement of VAT-1 in Phosphatidylserine Transfer from the Endoplasmic Reticulum to Mitochondria.

    PubMed

    Junker, Mirco; Rapoport, Tom A

    2015-12-01

    Mitochondria receive phosphatidylserine (PS) from the endoplasmic reticulum (ER), but how PS is moved from the ER to mitochondria is unclear. Current models postulate a physical link between the organelles, but no involvement of cytosolic proteins. Here, we have reconstituted PS transport from the ER to mitochondria in vitro using Xenopus egg components. Transport is independent of ER proteins, but is dependent on a cytosolic factor that has a preferential affinity for PS. Crosslinking with a photoactivatable PS analog identified VAT-1 as a candidate for a cytosolic PS transport protein. Recombinant, purified VAT-1 stimulated PS transport into mitochondria and depletion of VAT-1 from Xenopus cytosol with specific antibodies led to a reduction of transport. Our results suggest that cytosolic factors have a role in PS transport from the ER to mitochondria, implicate VAT-1 in the transport process, and indicate that physical contact between the organelles is not essential.

  10. Lidocaine Induces Endoplasmic Reticulum Stress-Associated Apoptosis in Vitro and in Vivo

    PubMed Central

    Hong, Dae Young; Kwon, Kisang; Lee, Kyeong Ryong; Choi, Young Jin; Goo, Tae-Won; Yu, Kweon; Kim, Seung-Whan; Kwon, O-Yu

    2011-01-01

    We demonstrated that upregulation of both gene expression of endoplasmic reticulum (ER) stress chaperones (BiP, calnexin, calreticulin, and PDI) and ER stress sensors (ATF6, IRE1 and PERK) was induced by lidocaine, a local anesthetic, in PC12 cells. In addition to gene regulation, lidocaine also induced typical ER stress phenomena such as ART6 proteolytic cleavage, eIF2 alpha phosphorylation, and XBP1 mRNA splicing. In in vivo experiments, while lidocaine downregulated gene expression of antiapoptotic factors (Bcl-2 and Bcl-xl), pro-apoptotic factor (Bak and Bax) gene expression was upregulated. Furthermore, lidocaine induced apoptosis, as measured histochemically, and upregulated PARP1, a DNA damage repair enzyme. These results are the first to show that lidocaine induces apoptosis through ER stress in vitro and in vivo. PMID:22174623

  11. Endoplasmic Reticulum Stress in Intestinal Epithelial Cell Function and Inflammatory Bowel Disease

    PubMed Central

    Luo, Katherine; Cao, Stewart Siyan

    2015-01-01

    In eukaryotic cells, perturbation of protein folding homeostasis in the endoplasmic reticulum (ER) causes accumulation of unfolded and misfolded proteins in the ER lumen, which activates intracellular signaling pathways termed the unfolded protein response (UPR). Recent studies have linked ER stress and the UPR to inflammatory bowel disease (IBD). The microenvironment of the ER is affected by a myriad of intestinal luminal molecules, implicating ER stress and the UPR in proper maintenance of intestinal homeostasis. Several intestinal cell populations, including Paneth and goblet cells, require robust ER function for protein folding, maturation, and secretion. Prolonged ER stress and impaired UPR signaling may cause IBD through: (1) induction of intestinal epithelial cell apoptosis, (2) disruption of mucosal barrier function, and (3) induction of the proinflammatory response in the gut. Based on our increased understanding of ER stress in IBD, new pharmacological approaches can be developed to improve intestinal homeostasis by targeting ER protein-folding in the intestinal epithelial cells (IECs). PMID:25755668

  12. Compartmentalization of the endoplasmic reticulum in the early C. elegans embryos.

    PubMed

    Lee, Zuo Yen; Prouteau, Manoël; Gotta, Monica; Barral, Yves

    2016-09-12

    The one-cell Caenorhabditis elegans embryo is polarized to partition fate determinants between the cell lineages generated during its first division. Using fluorescence loss in photobleaching, we find that the endoplasmic reticulum (ER) of the C. elegans embryo is physically continuous throughout the cell, but its membrane is compartmentalized shortly before nuclear envelope breakdown into an anterior and a posterior domain, indicating that a diffusion barrier forms in the ER membrane between these two domains. Using mutants with disorganized ER, we show that ER compartmentalization is independent of the morphological transition that the ER undergoes in mitosis. In contrast, compartmentalization takes place at the position of the future cleavage plane in a par-3-dependent manner. Together, our data indicate that the ER membrane is compartmentalized in cells as diverse as budding yeast, mouse neural stem cells, and the early C. elegans embryo. PMID:27597753

  13. Signaling Networks Converge on TORC1-SREBP Activity to Promote Endoplasmic Reticulum Homeostasis

    PubMed Central

    Sanchez-Alvarez, Miguel; Finger, Fabian; Arias-Garcia, Maria del Mar; Bousgouni, Vicky; Pascual-Vargas, Patricia; Bakal, Chris

    2014-01-01

    The function and capacity of the endoplasmic reticulum (ER) is determined by multiple processes ranging from the local regulation of peptide translation, translocation, and folding, to global changes in lipid composition. ER homeostasis thus requires complex interactions amongst numerous cellular components. However, describing the networks that maintain ER function during changes in cell behavior and environmental fluctuations has, to date, proven difficult. Here we perform a systems-level analysis of ER homeostasis, and find that although signaling networks that regulate ER function have a largely modular architecture, the TORC1-SREBP signaling axis is a central node that integrates signals emanating from different sub-networks. TORC1-SREBP promotes ER homeostasis by regulating phospholipid biosynthesis and driving changes in ER morphology. In particular, our network model shows TORC1-SREBP serves to integrate signals promoting growth and G1-S progression in order to maintain ER function during cell proliferation. PMID:25007267

  14. Transit of H2O2 across the endoplasmic reticulum membrane is not sluggish.

    PubMed

    Appenzeller-Herzog, Christian; Bánhegyi, Gabor; Bogeski, Ivan; Davies, Kelvin J A; Delaunay-Moisan, Agnès; Forman, Henry Jay; Görlach, Agnes; Kietzmann, Thomas; Laurindo, Francisco; Margittai, Eva; Meyer, Andreas J; Riemer, Jan; Rützler, Michael; Simmen, Thomas; Sitia, Roberto; Toledano, Michel B; Touw, Ivo P

    2016-05-01

    Cellular metabolism provides various sources of hydrogen peroxide (H2O2) in different organelles and compartments. The suitability of H2O2 as an intracellular signaling molecule therefore also depends on its ability to pass cellular membranes. The propensity of the membranous boundary of the endoplasmic reticulum (ER) to let pass H2O2 has been discussed controversially. In this essay, we challenge the recent proposal that the ER membrane constitutes a simple barrier for H2O2 diffusion and support earlier data showing that (i) ample H2O2 permeability of the ER membrane is a prerequisite for signal transduction, (ii) aquaporin channels are crucially involved in the facilitation of H2O2 permeation, and (iii) a proper experimental framework not prone to artifacts is necessary to further unravel the role of H2O2 permeation in signal transduction and organelle biology.

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

    PubMed

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

    2014-03-01

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

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

    PubMed Central

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

    2014-01-01

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

  17. Facilitation of DNA damage-induced apoptosis by endoplasmic reticulum protein mitsugumin23

    SciTech Connect

    Yamazaki, Tetsuo; Sasaki, Nozomi; Nishi, Miyuki; Takeshima, Hiroshi

    2010-02-05

    The endoplasmic reticulum (ER) emanates context-dependent signals, thereby mediating cellular response to a variety of stresses. However, the underlying molecular mechanisms have been enigmatic. To better understand the signaling capacity of the ER, we focused on roles played by mitsugumin23 (MG23), a protein residing predominantly in this organelle. Overexpression of MG23 in human embryonic kidney 293T cells specifically enhanced apoptosis triggered by etoposide, a DNA-damaging anti-cancer drug. Conversely, genetic deletion of MG23 reduced susceptibility of thymocytes to DNA damage-induced apoptosis, which was demonstrated by whole-body irradiation experiments. In this setting, induction of the tumor-suppressor gene p53 was attenuated in MG23-knockout thymocytes as compared with their wild-type counterparts, consistent with the elevated radioresistance. It is therefore suggested that MG23 is an essential component of ER-generated lethal signals provoked upon DNA damage, specifying cell fate under pathophysiological conditions.

  18. Endoplasmic reticulum stress inhibition is a valid therapeutic strategy in vitrifying oocytes.

    PubMed

    Zhao, Nan; Liu, Xue-Jun; Li, Jun-Tao; Zhang, Ling; Fu, Yang; Zhang, Ya-Jie; Chen, Ru-Xin; Wei, Xiao-Qing; Wang, Rui; Wang, Yu; Zhang, Jian-Min

    2015-02-01

    The aim of this study is to determine the link between oocyte cryopreservation and endoplasmic reticulum (ER) stress; whether ER stress inhibition improves the efficiency of oocyte vitrification is also explored. Oocytes from mice were exposure to tauroursodeoxycholic acid (TUDCA, an ER stress inhibitor) or TM (tunicamycin, an ER stress inducer) with or without vitrification. The expressions of X-box binding protein-1 (XBP-1) protein and caspase-12 protein, viability of vitrified-warmed oocytes, and their subsequent embryo competence were measured. The levels of XBP-1 protein and caspase-12 protein expression in vitrified-warmed oocytes were significantly higher than those of fresh control oocytes. TUDCA improved the viability of vitrified-warmed oocytes and their subsequent embryo competence. Mouse oocyte cryopreservation is associated with ER stress, and ER stress inhibition improves the efficiency of oocyte vitrification.

  19. Yeast Endoplasmic Reticulum Sequestration Screening for the Engineering of Proteases from Libraries Expressed in Yeast.

    PubMed

    Yi, Li; Taft, Joseph M; Li, Qing; Gebhard, Mark C; Georgiou, George; Iverson, Brent L

    2015-01-01

    There is significant interest in engineering proteases with desired proteolytic properties. We describe a high-throughput fluorescence-activated cell sorting (FACS) assay for detecting altered proteolytic activity of protease in yeast, at the single cell level. This assay relies on coupling yeast endoplasmic reticulum (ER) retention, yeast surface display, and FACS analysis. The method described here allows facile screening of large libraries, and of either protease or substrate variants, including the screening of protease libraries against substrate libraries. We demonstrate the application of this technique in the screening of libraries of Tobacco Etch Virus protease (TEV-P) for altered proteolytic activities. In addition, the generality of this method is also validated by other proteases such as human granzyme K and the hepatitis C virus protease, and the human Abelson tyrosine kinase. PMID:26060071

  20. Endoplasmic reticulum stress and the on site function of resident PTP1B.

    PubMed

    Popov, Doina

    2012-06-15

    Growing evidence links the stress at the endoplasmic reticulum (ER) to pathologies such as diabetes mellitus, obesity, liver, heart, renal and neurodegenerative diseases, endothelial dysfunction, atherosclerosis, and cancer. Therefore, identification of molecular pathways beyond ER stress and their appropriate modulation might alleviate the stress, and direct toward novel tools to fight this disturbance. An interesting resident of the ER membrane is protein tyrosine phosphatase 1B (PTP1B), an enzyme that negatively regulates insulin and leptin signaling, contributing to insulin and leptin resistance. Recently, new functions of PTP1B have been established linked to ER stress response. This review evaluates the novel data on ER stressors, discusses the mechanisms beyond PTP1B function in the ER stress response, and emphasizes the potential therapeutic exploitation of PTP1B to relieve ER stress. PMID:22609202

  1. Endoplasmic reticulum stress-mediated induction of SESTRIN 2 potentiates cell survival

    PubMed Central

    Ayo, Abiodun; Pakos-Zebrucka, Karolina; Patterson, John B

    2016-01-01

    Upregulation of SESTRIN 2 (SESN2) has been reported in response to diverse cellular stresses. In this study we demonstrate SESTRIN 2 induction following endoplasmic reticulum (ER) stress. ER stress-induced increases in SESTRIN 2 expression were dependent on both PERK and IRE1/XBP1 arms of the unfolded protein response (UPR). SESTRIN 2 induction, post ER stress, was responsible for mTORC1 inactivation and contributed to autophagy induction. Conversely, knockdown of SESTRIN 2 prolonged mTORC1 signaling, repressed autophagy and increased ER stress-induced cell death. Unexpectedly, the increase in ER stress-induced cell death was not linked to autophagy inhibition. Analysis of UPR pathways identified prolonged eIF2α, ATF4 and CHOP signaling in SESTRIN 2 knockdown cells following ER stress. SESTRIN 2 regulation enables UPR derived signals to indirectly control mTORC1 activity shutting down protein translation thus preventing further exacerbation of ER stress. PMID:26930721

  2. Sc65-Null Mice Provide Evidence for a Novel Endoplasmic Reticulum Complex Regulating Collagen Lysyl Hydroxylation

    PubMed Central

    Weis, MaryAnn; Rai, Jyoti; Hudson, David M.; Dimori, Milena; Zimmerman, Sarah M.; Hogue, William R.; Swain, Frances L.; Burdine, Marie S.; Mackintosh, Samuel G.; Tackett, Alan J.; Suva, Larry J.; Eyre, David R.

    2016-01-01

    Collagen is a major component of the extracellular matrix and its integrity is essential for connective tissue and organ function. The importance of proteins involved in intracellular collagen post-translational modification, folding and transport was recently highlighted from studies on recessive forms of osteogenesis imperfecta (OI). Here we describe the critical role of SC65 (Synaptonemal Complex 65, P3H4), a leprecan-family member, as part of an endoplasmic reticulum (ER) complex with prolyl 3-hydroxylase 3. This complex affects the activity of lysyl-hydroxylase 1 potentially through interactions with the enzyme and/or cyclophilin B. Loss of Sc65 in the mouse results in instability of this complex, altered collagen lysine hydroxylation and cross-linking leading to connective tissue defects that include low bone mass and skin fragility. This is the first indication of a prolyl-hydroxylase complex in the ER controlling lysyl-hydroxylase activity during collagen synthesis. PMID:27119146

  3. Presenilin 2 Modulates Endoplasmic Reticulum-Mitochondria Coupling by Tuning the Antagonistic Effect of Mitofusin 2.

    PubMed

    Filadi, Riccardo; Greotti, Elisa; Turacchio, Gabriele; Luini, Alberto; Pozzan, Tullio; Pizzo, Paola

    2016-06-01

    Communication between organelles plays key roles in cell biology. In particular, physical and functional coupling of the endoplasmic reticulum (ER) and mitochondria is crucial for regulation of various physiological and pathophysiological processes. Here, we demonstrate that Presenilin 2 (PS2), mutations in which underlie familial Alzheimer's disease (FAD), promotes ER-mitochondria coupling only in the presence of mitofusin 2 (Mfn2). PS2 is not necessary for the antagonistic effect of Mfn2 on organelle coupling, although its abundance can tune it. The two proteins physically interact, whereas their homologues Mfn1 and PS1 are dispensable for this interplay. Moreover, PS2 mutants associated with FAD are more effective than the wild-type form in modulating ER-mitochondria tethering because their binding to Mfn2 in mitochondria-associated membranes is favored. We propose a revised model for ER-mitochondria interaction to account for these findings and discuss possible implications for FAD pathogenesis. PMID:27239030

  4. The essential functions of endoplasmic reticulum chaperones in hepatic lipid metabolism.

    PubMed

    Zhang, LiChun; Wang, Hong-Hui

    2016-07-01

    The endoplasmic reticulum (ER) is an essential organelle for protein and lipid synthesis in hepatocytes. ER homeostasis is vital to maintain normal hepatocyte physiology. Perturbed ER functions causes ER stress associated with accumulation of unfolded protein in the ER that activates a series of adaptive signalling pathways, termed unfolded protein response (UPR). The UPR regulates ER chaperone levels to preserve ER protein-folding environment to protect the cell from ER stress. Recent findings reveal an array of ER chaperones that alter the protein-folding environment in the ER of hepatocytes and contribute to dysregulation of hepatocyte lipid metabolism and liver disease. In this review, we will discuss the specific functions of these chaperones in regulation of lipid metabolism, especially de novo lipogenesis and lipid transport and demonstrate their homeostatic role not only for ER-protein synthesis but also for lipid metabolism in hepatocyte. PMID:27133206

  5. Sc65-Null Mice Provide Evidence for a Novel Endoplasmic Reticulum Complex Regulating Collagen Lysyl Hydroxylation.

    PubMed

    Heard, Melissa E; Besio, Roberta; Weis, MaryAnn; Rai, Jyoti; Hudson, David M; Dimori, Milena; Zimmerman, Sarah M; Kamykowski, Jeffrey A; Hogue, William R; Swain, Frances L; Burdine, Marie S; Mackintosh, Samuel G; Tackett, Alan J; Suva, Larry J; Eyre, David R; Morello, Roy

    2016-04-01

    Collagen is a major component of the extracellular matrix and its integrity is essential for connective tissue and organ function. The importance of proteins involved in intracellular collagen post-translational modification, folding and transport was recently highlighted from studies on recessive forms of osteogenesis imperfecta (OI). Here we describe the critical role of SC65 (Synaptonemal Complex 65, P3H4), a leprecan-family member, as part of an endoplasmic reticulum (ER) complex with prolyl 3-hydroxylase 3. This complex affects the activity of lysyl-hydroxylase 1 potentially through interactions with the enzyme and/or cyclophilin B. Loss of Sc65 in the mouse results in instability of this complex, altered collagen lysine hydroxylation and cross-linking leading to connective tissue defects that include low bone mass and skin fragility. This is the first indication of a prolyl-hydroxylase complex in the ER controlling lysyl-hydroxylase activity during collagen synthesis.

  6. Mutations in the SPTLC1 protein cause mitochondrial structural abnormalities and endoplasmic reticulum stress in lymphoblasts.

    PubMed

    Myers, Simon J; Malladi, Chandra S; Hyland, Ryan A; Bautista, Tara; Boadle, Ross; Robinson, Phillip J; Nicholson, Garth A

    2014-07-01

    Mutations in serine palmitoyltransferase long chain subunit 1 (SPTLC1) cause the typical length-dependent axonal degeneration hereditary sensory neuropathy type 1 (HSN1). Transmission electron microscopy studies on SPTLC1 mutant lymphoblasts derived from patients revealed specific structural abnormalities of mitochondria. Swollen mitochondria with abnormal cristae were clustered around the nucleus, with some mitochondria being wrapped in rough endoplasmic reticulum (ER) membranes. Total mitochondrial counts revealed a significant change in mitochondrial numbers between healthy and diseased lymphocytes but did not reveal any change in length to width ratios nor were there any changes to cellular function. However, there was a notable change in ER homeostasis, as assessed using key ER stress markers, BiP and ERO1-Lα, displaying reduced protein expression. The observations suggest that SPTLC1 mutations cause mitochondrial abnormalities and ER stress in HSN1 cells. PMID:24673574

  7. Endoplasmic Reticulum: The Favorite Intracellular Niche for Viral Replication and Assembly

    PubMed Central

    Romero-Brey, Inés; Bartenschlager, Ralf

    2016-01-01

    The endoplasmic reticulum (ER) is the largest intracellular organelle. It forms a complex network of continuous sheets and tubules, extending from the nuclear envelope (NE) to the plasma membrane. This network is frequently perturbed by positive-strand RNA viruses utilizing the ER to create membranous replication factories (RFs), where amplification of their genomes occurs. In addition, many enveloped viruses assemble progeny virions in association with ER membranes, and viruses replicating in the nucleus need to overcome the NE barrier, requiring transient changes of the NE morphology. This review first summarizes some key aspects of ER morphology and then focuses on the exploitation of the ER by viruses for the sake of promoting the different steps of their replication cycles. PMID:27338443

  8. Dysfunctional tubular endoplasmic reticulum constitutes a pathological feature of Alzheimer's disease.

    PubMed

    Sharoar, M G; Shi, Q; Ge, Y; He, W; Hu, X; Perry, G; Zhu, X; Yan, R

    2016-09-01

    Pathological features in Alzheimer's brains include mitochondrial dysfunction and dystrophic neurites (DNs) in areas surrounding amyloid plaques. Using a mouse model that overexpresses reticulon 3 (RTN3) and spontaneously develops age-dependent hippocampal DNs, here we report that DNs contain both RTN3 and REEPs, topologically similar proteins that can shape tubular endoplasmic reticulum (ER). Importantly, ultrastructural examinations of such DNs revealed gradual accumulation of tubular ER in axonal termini, and such abnormal tubular ER inclusion is found in areas surrounding amyloid plaques in biopsy samples from Alzheimer's disease (AD) brains. Functionally, abnormally clustered tubular ER induces enhanced mitochondrial fission in the early stages of DN formation and eventual mitochondrial degeneration at later stages. Furthermore, such DNs are abrogated when RTN3 is ablated in aging and AD mouse models. Hence, abnormally clustered tubular ER can be pathogenic in brain regions: disrupting mitochondrial integrity, inducing DNs formation and impairing cognitive function in AD and aging brains. PMID:26619807

  9. Possible Pharmacological Approach Targeting Endoplasmic Reticulum Stress to Ameliorate Leptin Resistance in Obesity

    PubMed Central

    Hosoi, Toru; Ozawa, Koichiro

    2016-01-01

    Obesity is associated with metabolic syndrome, such as diabetes, hypertension, and hyperlipidemia. Therefore, drug development for the treatment of obesity is needed. Leptin is an anti-obesity hormone that inhibits food intake and increases energy metabolism, and, as such, treatments involving leptin were expected to be beneficial for obesity; however, since most obese patients are in a state of leptin resistance, these treatments may not be useful. Therefore, the amelioration of leptin resistance has recently been attracting interest as a treatment for obesity. The mechanisms underlying the development of leptin resistance need to be elucidated in more detail. Endoplasmic reticulum (ER) stress was recently suggested to be involved in the pathogenesis of leptin resistance. The molecular mechanisms responsible for leptin resistance and possible pharmacological treatments for obesity have been discussed herein, with a focus on ER stress. PMID:27375555

  10. ERp19 and ERp46, new members of the thioredoxin family of endoplasmic reticulum proteins.

    PubMed

    Knoblach, Barbara; Keller, Bernd O; Groenendyk, Jody; Aldred, Sandi; Zheng, Jing; Lemire, Bernard D; Li, Liang; Michalak, Marek

    2003-10-01

    Using a proteomic analysis of the luminal environment of the endoplasmic reticulum (ER), we have identified 141 proteins, of which 6 were previously unknown. Two newly discovered ER luminal proteins, designated ERp19 and ERp46, are related to protein disulphide isomerase. Western and Northern blot analyses revealed that both ERp19 and ERp46 and their respective mRNAs are highly expressed in the liver as compared with other tissues. Both proteins were enriched in purified liver ER vesicles and were localized specifically to the ER in McA-RH7777 hepatocytes. Functional analysis with yeast complementation studies showed that ERp46 but not ERp19 can substitute for protein disulphide isomerase function in vivo.

  11. The roles of endoplasmic reticulum stress response in female mammalian reproduction.

    PubMed

    Yang, Yanzhou; Pei, Xiuying; Jin, Yaping; Wang, Yanrong; Zhang, Cheng

    2016-03-01

    Endoplasmic reticulum stress (ERS) activates a protective pathway, called the unfold protein response, for maintaining cellular homeostasis, but cellular apoptosis is triggered by excessive or persistent ERS. Several recent studies imply that the ERS response might have broader physiological roles in the various reproductive processes of female mammals, including embryo implantation, decidualization, preimplantation embryonic development, follicle atresia, and the development of the placenta. This review summarizes the existing data concerning the molecular and biological roles of the ERS response. The study of the functions of the ERS response in mammalian reproduction might provide novel insights into and an understanding of reproductive cell survival and apoptosis under physiological and pathological conditions. The ERS response is a novel signaling pathway for reproductive cell survival and apoptosis. Infertility might be a result of disturbing the ERS response during the process of female reproduction. PMID:26022337

  12. A Non-enveloped Virus Hijacks Host Disaggregation Machinery to Translocate across the Endoplasmic Reticulum Membrane

    PubMed Central

    Ravindran, Madhu Sudhan; Bagchi, Parikshit; Inoue, Takamasa; Tsai, Billy

    2015-01-01

    Mammalian cytosolic Hsp110 family, in concert with the Hsc70:J-protein complex, functions as a disaggregation machinery to rectify protein misfolding problems. Here we uncover a novel role of this machinery in driving membrane translocation during viral entry. The non-enveloped virus SV40 penetrates the endoplasmic reticulum (ER) membrane to reach the cytosol, a critical infection step. Combining biochemical, cell-based, and imaging approaches, we find that the Hsp110 family member Hsp105 associates with the ER membrane J-protein B14. Here Hsp105 cooperates with Hsc70 and extracts the membrane-penetrating SV40 into the cytosol, potentially by disassembling the membrane-embedded virus. Hence the energy provided by the Hsc70-dependent Hsp105 disaggregation machinery can be harnessed to catalyze a membrane translocation event. PMID:26244546

  13. Ceramide transport from endoplasmic reticulum to Golgi apparatus is not vesicle-mediated.

    PubMed

    Kok, J W; Babia, T; Klappe, K; Egea, G; Hoekstra, D

    1998-08-01

    Ceramide (Cer) transfer from the endoplasmic reticulum (ER) to the Golgi apparatus was measured under conditions that block vesicle-mediated protein transfer. This was done either in intact cells by reducing the incubation temperature to 15 degreesC, or in streptolysin O-permeabilized cells by manipulating the intracellular environment. In both cases, Cer transfer was not inhibited, as demonstrated by the biosynthesis of ceramide monohexosides and sphingomyelin (SM) de novo from metabolically (with [14C]serine) labelled Cer. This assay is based on the knowledge that Cer is synthesized, starting from serine and palmitoyl-CoA, at the ER, whereas glycosphingolipids and SM are synthesized in the (early) Golgi apparatus. Formation of [14C]glycosphingolipids and [14C]SM was observed under conditions that block vesicle-mediated vesicular stomatitis virus glycoprotein transport. These results indicate that [14C]Cer is transferred from ER to Golgi by a non-vesicular mechanism.

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

    PubMed Central

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

    2016-01-01

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

  15. Hydrogen Sulfide Improves Vascular Calcification in Rats by Inhibiting Endoplasmic Reticulum Stress

    PubMed Central

    Yang, Rui; Teng, Xu; Li, Hui; Xue, Hong-Mei; Guo, Qi; Xiao, Lin; Wu, Yu-Ming

    2016-01-01

    In this study, the vitamin D3 plus nicotine (VDN) model of rats was used to prove that H2S alleviates vascular calcification (VC) and phenotype transformation of vascular smooth muscle cells (VSMC). Besides, H2S can also inhibit endoplasmic reticulum stress (ERS) of calcified aortic tissues. The effect of H2S on alleviating VC and phenotype transformation of VSMC can be blocked by TM, while PBA also alleviated VC and phenotype transformation of VSMC that was similar to the effect of H2S. These results suggest that H2S may alleviate rat aorta VC by inhibiting ERS, providing new target and perspective for prevention and treatment of VC. PMID:27022436

  16. Crystal structures reveal transient PERK luminal domain tetramerization in endoplasmic reticulum stress signaling

    PubMed Central

    Carrara, Marta; Prischi, Filippo; Nowak, Piotr R; Ali, Maruf MU

    2015-01-01

    Stress caused by accumulation of misfolded proteins within the endoplasmic reticulum (ER) elicits a cellular unfolded protein response (UPR) aimed at maintaining protein-folding capacity. PERK, a key upstream component, recognizes ER stress via its luminal sensor/transducer domain, but the molecular events that lead to UPR activation remain unclear. Here, we describe the crystal structures of mammalian PERK luminal domains captured in dimeric state as well as in a novel tetrameric state. Small angle X-ray scattering analysis (SAXS) supports the existence of both crystal structures also in solution. The salient feature of the tetramer interface, a helix swapped between dimers, implies transient association. Moreover, interface mutations that disrupt tetramer formation in vitro reduce phosphorylation of PERK and its target eIF2α in cells. These results suggest that transient conversion from dimeric to tetrameric state may be a key regulatory step in UPR activation. PMID:25925385

  17. Protein folding in the endoplasmic reticulum: lessons from the human chorionic gonadotropin beta subunit.

    PubMed Central

    Ruddon, R. W.; Sherman, S. A.; Bedows, E.

    1996-01-01

    There have been few studies of protein folding in the endoplasmic reticulum of intact mammalian cells. In the one case where the in vivo and in vitro folding pathways of a mammalian secretory protein have been compared, the folding of the human chorionic gonadotropin beta subunit (hCG-beta), the order of formation of the detected folding intermediates is the same. The rate and efficiency with which multidomain proteins such as hCG-beta fold to native structure in intact cells is higher than in vitro, although intracellular rates of folding of the beta subunit can be approached in vitro in the presence of an optimal redox potential and protein disulfide isomerase. Understanding how proteins fold in vivo may provide a new way to diagnose and treat human illnesses that occur due to folding defects. PMID:8844836

  18. Endoplasmic reticulum stress-mediated pathways to both apoptosis and autophagy: Significance for melanoma treatment

    PubMed Central

    Hassan, Mohamed; Selimovic, Denis; Hannig, Matthias; Haikel, Youssef; Brodell, Robert T; Megahed, Mossaad

    2015-01-01

    Melanoma is the most aggressive form of skin cancer. Disrupted intracellular signaling pathways are responsible for melanoma's extraordinary resistance to current chemotherapeutic modalities. The pathophysiologic basis for resistance to both chemo- and radiation therapy is rooted in altered genetic and epigenetic mechanisms that, in turn, result in the impairing of cell death machinery and/or excessive activation of cell growth and survival-dependent pathways. Although most current melanoma therapies target mitochondrial dysregulation, there is increasing evidence that endoplasmic reticulum (ER) stress-associated pathways play a role in the potentiation, initiation and maintenance of cell death machinery and autophagy. This review focuses on the reliability of ER-associated pathways as therapeutic targets for melanoma treatment. PMID:26618107

  19. VCP and ATL1 regulate endoplasmic reticulum and protein synthesis for dendritic spine formation

    PubMed Central

    Shih, Yu-Tzu; Hsueh, Yi-Ping

    2016-01-01

    Imbalanced protein homeostasis, such as excessive protein synthesis and protein aggregation, is a pathogenic hallmark of a range of neurological disorders. Here, using expression of mutant proteins, a knockdown approach and disease mutation knockin mice, we show that VCP (valosin-containing protein), together with its cofactor P47 and the endoplasmic reticulum (ER) morphology regulator ATL1 (Atlastin-1), regulates tubular ER formation and influences the efficiency of protein synthesis to control dendritic spine formation in neurons. Strengthening the significance of protein synthesis in dendritic spinogenesis, the translation blocker cyclohexamide and the mTOR inhibitor rapamycin reduce dendritic spine density, while a leucine supplement that increases protein synthesis ameliorates the dendritic spine defects caused by Vcp and Atl1 deficiencies. Because VCP and ATL1 are the causative genes of several neurodegenerative and neurodevelopmental disorders, we suggest that impaired ER formation and inefficient protein synthesis are significant in the pathogenesis of multiple neurological disorders. PMID:26984393

  20. VCP and ATL1 regulate endoplasmic reticulum and protein synthesis for dendritic spine formation.

    PubMed

    Shih, Yu-Tzu; Hsueh, Yi-Ping

    2016-03-17

    Imbalanced protein homeostasis, such as excessive protein synthesis and protein aggregation, is a pathogenic hallmark of a range of neurological disorders. Here, using expression of mutant proteins, a knockdown approach and disease mutation knockin mice, we show that VCP (valosin-containing protein), together with its cofactor P47 and the endoplasmic reticulum (ER) morphology regulator ATL1 (Atlastin-1), regulates tubular ER formation and influences the efficiency of protein synthesis to control dendritic spine formation in neurons. Strengthening the significance of protein synthesis in dendritic spinogenesis, the translation blocker cyclohexamide and the mTOR inhibitor rapamycin reduce dendritic spine density, while a leucine supplement that increases protein synthesis ameliorates the dendritic spine defects caused by Vcp and Atl1 deficiencies. Because VCP and ATL1 are the causative genes of several neurodegenerative and neurodevelopmental disorders, we suggest that impaired ER formation and inefficient protein synthesis are significant in the pathogenesis of multiple neurological disorders.

  1. Endoplasmic reticulum stress: relevance and therapeutics in central nervous system diseases.

    PubMed

    Zhang, Hong-Yu; Wang, Zhou-guang; Lu, Xiang-Hong; Kong, Xiao-Xia; Wu, Fen-Zan; Lin, Li; Tan, Xiaohua; Ye, Li-Bing; Xiao, Jian

    2015-01-01

    Endoplasmic reticulum (ER) stress plays an important role in a range of neurological disorders, such as neurodegenation diseases, cerebral ischemia, spinal cord injury, sclerosis, and diabetic neuropathy. Protein misfolding and accumulation in the ER lumen initiate unfolded protein response in energy-starved neurons which are relevant to toxic effects. In neurological disorders, such as Alzheimer's disease, Parkinson's disease, and Huntington's disease, ER dysfunction is well recognized, but the mechanisms remain unclear. In stroke and ischemia, spinal cord injury, and amyotrophic lateral sclerosis, chronic activation of ER stress is considered as main pathogeny which causes neuronal disorders. By targeting components of these ER signaling responses, to explore clinical treatment strategies or new drugs in CNS neurological diseases might become possible and valuable in the future.

  2. Establishment of a system for monitoring endoplasmic reticulum redox state in mammalian cells

    PubMed Central

    Kanekura, Kohsuke; Ishigaki, Shinsuke; Merksamer, Philip I.; Papa, Feroz R.; Urano, Fumihiko

    2014-01-01

    The endoplasmic reticulum (ER) performs a critical role in the oxidative folding of nascent proteins such that perturbations to ER homeostasis may lead to protein misfolding and subsequent pathological processes. Among the mechanisms for maintaining ER homeostasis is a redox regulation, which is a critical determinant of the fate of ER stressed cells. Here we report the establishment of a system for monitoring ER redox state in mammalian cells. The new ER redox sensing system was developed based on the previously described monitoring system in yeast. Our system could successfully monitor the dynamic ER redox state in mammalian cells. Using this system, we find that manipulation of ER oxidases changes ER redox state. The mammalian ER redox sensing system could be used to study the mechanisms of ER redox regulation and provide a foundation for an approach to develop novel therapeutic modalities for human diseases related to dysregulated ER homeostasis including diabetes, neurodegeneration and Wolfram syndrome. PMID:24042438

  3. Endoplasmic Reticulum: The Favorite Intracellular Niche for Viral Replication and Assembly.

    PubMed

    Romero-Brey, Inés; Bartenschlager, Ralf

    2016-01-01

    The endoplasmic reticulum (ER) is the largest intracellular organelle. It forms a complex network of continuous sheets and tubules, extending from the nuclear envelope (NE) to the plasma membrane. This network is frequently perturbed by positive-strand RNA viruses utilizing the ER to create membranous replication factories (RFs), where amplification of their genomes occurs. In addition, many enveloped viruses assemble progeny virions in association with ER membranes, and viruses replicating in the nucleus need to overcome the NE barrier, requiring transient changes of the NE morphology. This review first summarizes some key aspects of ER morphology and then focuses on the exploitation of the ER by viruses for the sake of promoting the different steps of their replication cycles. PMID:27338443

  4. Membrane expansion alleviates endoplasmic reticulum stress independently of the unfolded protein response

    PubMed Central

    Prinz, William A.; Thorn, Kurt S.; Voss, Christiane; Walter, Peter

    2009-01-01

    Cells constantly adjust the sizes and shapes of their organelles according to need. In this study, we examine endoplasmic reticulum (ER) membrane expansion during the unfolded protein response (UPR) in the yeast Saccharomyces cerevisiae. We find that membrane expansion occurs through the generation of ER sheets, requires UPR signaling, and is driven by lipid biosynthesis. Uncoupling ER size control and the UPR reveals that membrane expansion alleviates ER stress independently of an increase in ER chaperone levels. Converting the sheets of the expanded ER into tubules by reticulon overexpression does not affect the ability of cells to cope with ER stress, showing that ER size rather than shape is the key factor. Thus, increasing ER size through membrane synthesis is an integral yet distinct part of the cellular program to overcome ER stress. PMID:19948500

  5. Alterations in Mitochondrial and Endoplasmic Reticulum Signaling by p53 Mutants

    PubMed Central

    Giorgi, Carlotta; Bonora, Massimo; Missiroli, Sonia; Morganti, Claudia; Morciano, Giampaolo; Wieckowski, Mariusz R.; Pinton, Paolo

    2016-01-01

    The p53 protein is probably the most important tumor suppressor, acting as a nuclear transcription factor primarily through the modulation of cell death. However, currently, it is well accepted that p53 can also exert important transcription-independent pro-cell death actions. Indeed, cytosolic localization of endogenous wild-type or transactivation-deficient p53 is necessary and sufficient for the induction of apoptosis and autophagy. Here, we present the extra-nuclear activities of p53 associated with the mitochondria and the endoplasmic reticulum, highlighting the activities of the p53 mutants on these compartments. These two intracellular organelles play crucial roles in the regulation of cell death, and it is now well established that they also represent sites where p53 can accumulate. PMID:26942128

  6. Inhibin beta E is upregulated by drug-induced endoplasmic reticulum stress as a transcriptional target gene of ATF4

    SciTech Connect

    Brüning, Ansgar Matsingou, Christina; Brem, German Johannes; Rahmeh, Martina; Mylonas, Ioannis

    2012-10-15

    Inhibins and activins are gonadal peptide hormones of the transforming growth factor-β super family with important functions in the reproductive system. By contrast, the recently identified inhibin βE subunit, primarily expressed in liver cells, appears to exert functions unrelated to the reproductive system. Previously shown downregulation of inhibin βE in hepatoma cells and anti-proliferative effects of ectopic inhibin βE overexpression indicated growth-regulatory effects of inhibin βE. We observed a selective re-expression of the inhibin βE subunit in HepG2 hepatoblastoma cells, MCF7 breast cancer cells, and HeLa cervical cancer cells under endoplasmic reticulum stress conditions induced by tunicamycin, thapsigargin, and nelfinavir. Analysis of XPB1 splicing and ATF4 activation revealed that inhibin βE re-expression was associated with induction of the endoplasmic reticulum stress reaction by these drugs. Transfection of an ATF4 expression plasmid specifically induced inhibin βE expression in HeLa cells and indicates inhibin βE as a hitherto unidentified target gene of ATF4, a key transcription factor of the endoplasmic reticulum stress response. Therefore, the inhibin βE subunit defines not only a new player but also a possible new marker for drug-induced endoplasmic reticulum stress. -- Highlights: ► Endoplasmic reticulum stress induces inhibin beta E expression. ► Inhibin beta E is regulated by the transcription factor ATF4. ► Inhibin beta E expression can be used as a marker for drug-induced ER stress.

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

    SciTech Connect

    Luo, Ying; Li, Shu-Jun; Yang, Jian; Qiu, Yuan-Zhen; Chen, Fang-Ping

    2013-09-06

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

  8. ILDR2: an endoplasmic reticulum resident molecule mediating hepatic lipid homeostasis.

    PubMed

    Watanabe, Kazuhisa; Watson, Elizabeth; Cremona, Maria Laura; Millings, Elizabeth J; Lefkowitch, Jay H; Fischer, Stuart G; LeDuc, Charles A; Leibel, Rudolph L

    2013-01-01

    Ildr2, a modifier of diabetes susceptibility in obese mice, is expressed in most organs, including islets and hypothalamus, with reduced levels in livers of diabetes-susceptible B6.DBA mice congenic for a 1.8 Mb interval of Chromosome 1. In hepatoma and neuronal cells, ILDR2 is primarily located in the endoplasmic reticulum membrane. We used adenovirus vectors that express shRNA or are driven by the CMV promoter, respectively, to knockdown or overexpress Ildr2 in livers of wild type and ob/ob mice. Livers in knockdown mice were steatotic, with increased hepatic and circulating triglycerides and total cholesterol. Increased circulating VLDL, without reduction in triglyceride clearance suggests an effect of reduced hepatic ILDR2 on hepatic cholesterol clearance. In animals that overexpress Ildr2, hepatic triglyceride and total cholesterol levels were reduced, and strikingly so in ob/ob mice. There were no significant changes in body weight, energy expenditure or glucose/insulin homeostasis in knockdown or overexpressing mice. Knockdown mice showed reduced expression of genes mediating synthesis and oxidation of hepatic lipids, suggesting secondary suppression in response to increased hepatic lipid content. In Ildr2-overexpressing ob/ob mice, in association with reduced liver fat content, levels of transcripts related to neutral lipid synthesis and cholesterol were increased, suggesting "relief" of the secondary suppression imposed by lipid accumulation. Considering the fixed location of ILDR2 in the endoplasmic reticulum, we investigated the possible participation of ILDR2 in ER stress responses. In general, Ildr2 overexpression was associated with increases, and knockdown with decreases in levels of expression of molecular components of canonical ER stress pathways. We conclude that manipulation of Ildr2 expression in liver affects both lipid homeostasis and ER stress pathways. Given these reciprocal interactions, and the relatively extended time-course over which

  9. Intermittent selective clamping improves rat liver regeneration by attenuating oxidative and endoplasmic reticulum stress.

    PubMed

    Ben Mosbah, I; Duval, H; Mbatchi, S-F; Ribault, C; Grandadam, S; Pajaud, J; Morel, F; Boudjema, K; Compagnon, P; Corlu, A

    2014-03-06

    Intermittent clamping of the portal trial is an effective method to avoid excessive blood loss during hepatic resection, but this procedure may cause ischemic damage to liver. Intermittent selective clamping of the lobes to be resected may represent a good alternative as it exposes the remnant liver only to the reperfusion stress. We compared the effect of intermittent total or selective clamping on hepatocellular injury and liver regeneration. Entire hepatic lobes or only lobes to be resected were subjected twice to 10 min of ischemia followed by 5 min of reperfusion before hepatectomy. We provided evidence that the effect of intermittent clamping can be damaging or beneficial depending to its mode of application. Although transaminase levels were similar in all groups, intermittent total clamping impaired liver regeneration and increased apoptosis. In contrast, intermittent selective clamping improved liver protein secretion and hepatocyte proliferation when compared with standard hepatectomy. This beneficial effect was linked to better adenosine-5'-triphosphate (ATP) recovery, nitric oxide production, antioxidant activities and endoplasmic reticulum adaptation leading to limit mitochondrial damage and apoptosis. Interestingly, transient and early chaperone inductions resulted in a controlled activation of the unfolded protein response concomitantly to endothelial nitric oxide synthase, extracellular signal-regulated kinase-1/2 (ERK1/2) and p38 MAPK activation that favors liver regeneration. Endoplasmic reticulum stress is a central target through which intermittent selective clamping exerts its cytoprotective effect and improves liver regeneration. This procedure could be applied as a powerful protective modality in the field of living donor liver transplantation and liver surgery.

  10. Ebselen alters cellular oxidative status and induces endoplasmic reticulum stress in rat hippocampal astrocytes.

    PubMed

    Santofimia-Castaño, Patricia; Izquierdo-Alvarez, Alicia; de la Casa-Resino, Irene; Martinez-Ruiz, Antonio; Perez-Lopez, Marcos; Portilla, Juan C; Salido, Gines M; Gonzalez, Antonio

    2016-05-16

    Ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one) is an organoselenium radical scavenger compound, which has strong antioxidant and anti-inflammatory effects. Because of its properties, it may be protective against injury to the nervous tissue. However, evidence suggests that its glutathione peroxidase activity could underlie certain deleterious actions on cell physiology. In this study we have analyzed the effect of ebselen on rat hippocampal astrocytes in culture. Cellular oxidative status, cytosolic free-Ca(2+) concentration ([Ca(2+)]c), setting of endoplasmic reticulum stress and phosphorylation of glial fibrillary acidic protein and major mitogen-activated protein kinases were analyzed. Our results show that ebselen induced a concentration-dependent increase in the generation of reactive oxygen species in the mitochondria. We observed a concentration-dependent increase in global cysteine oxidation and in the level of malondialdehyde in the presence of ebselen. We also detected increases in catalase, glutathione S-transferase and glutathione reductase activity. Ebselen also evoked a concentration-dependent increase in [Ca(2+)]c. Moreover, we observed a concentration-dependent increase in the phosphorylation of the unfolded protein response markers, eukaryotic translation initiation factor 2α and X-box binding protein 1. Finally, ebselen also induced an increase in the phosphorylation of glial fibrillary acidic protein, SAPK/JNK, p38 MAPK and p44/42 MAPK. Our results provide strong evidence that implicate endoplasmic reticulum stress and activation of crucial mitogen-activated protein kinases in an oxidative damage of cells in the presence of ebselen. The compound thus might exert deleterious actions on astrocyte physiology that could compromise their function. PMID:27282967

  11. Identification of Two Novel Endoplasmic Reticulum Body-Specific Integral Membrane Proteins1[W][OA

    PubMed Central

    Yamada, Kenji; Nagano, Atsushi J.; Nishina, Momoko; Hara-Nishimura, Ikuko; Nishimura, Mikio

    2013-01-01

    The endoplasmic reticulum (ER) body, a large compartment specific to the Brassicales, accumulates β-glucosidase and possibly plays a role in the defense against pathogens and herbivores. Although the ER body is a subdomain of the ER, it is unclear whether any ER body-specific membrane protein exists. In this study, we identified two integral membrane proteins of the ER body in Arabidopsis (Arabidopsis thaliana) and termed them MEMBRANE PROTEIN OF ENDOPLASMIC RETICULUM BODY1 (MEB1) and MEB2. In Arabidopsis, a basic helix-loop-helix transcription factor, NAI1, and an ER body component, NAI2, regulate ER body formation. The expression profiles of MEB1 and MEB2 are similar to those of NAI1, NAI2, and ER body β-glucosidase PYK10 in Arabidopsis. The expression of MEB1 and MEB2 was reduced in the nai1 mutant, indicating that NAI1 regulates the expression of MEB1 and MEB2 genes. MEB1 and MEB2 proteins localize to the ER body membrane but not to the ER network, suggesting that these proteins are specifically recruited to the ER body membrane. MEB1 and MEB2 physically interacted with ER body component NAI2, and they were diffused throughout the ER network in the nai2 mutant, which has no ER body. Heterologous expression of MEB1 and MEB2 in yeast (Saccharomyces cerevisiae) suppresses iron and manganese toxicity, suggesting that MEB1 and MEB2 are metal transporters. These results indicate that the membrane of ER bodies has specific membrane proteins and suggest that the ER body is involved in defense against metal stress as well as pathogens and herbivores. PMID:23166355

  12. Ca2+-Dependent Endoplasmic Reticulum Stress Regulates Mechanical Stress-Mediated Cartilage Thinning.

    PubMed

    Zhu, M; Zhou, S; Huang, Z; Wen, J; Li, H

    2016-07-01

    Our previous study identified that endoplasmic reticulum stress (ERS) plays a critical role in chondrocyte apoptosis and mandibular cartilage thinning in response to compressive mechanical force, although the underlying mechanisms remain elusive. Because the endoplasmic reticulum (ER) is a primary site of intracellular Ca(2+) storage, we hypothesized that Ca(2+)-dependent ERS might be involved in mechanical stress-mediated mandibular cartilage thinning. In this study, we used in vitro and in vivo models to determine Ca(2+) concentrations, histological changes, subcellular changes, apoptosis, and the expression of ERS markers in mandibular cartilage and chondrocytes. The results showed that in chondrocytes, cytosolic Ca(2+) ([Ca(2+)]i) was dramatically increased by compressive mechanical force. Interestingly, the inhibition of Ca(2+) channels by ryanodine and 2-aminoethoxydiphenyl borate, inhibitors of ryanodine receptors and inositol trisphosphate receptors, respectively, partially rescued mechanical force-mediated mandibular cartilage thinning. Furthermore, chondrocyte apoptosis was also compromised by inhibiting the increase in [Ca(2+)]i that occurred in response to compressive mechanical force. Mechanistically, the ERS induced by compressive mechanical force was also repressed by [Ca(2+)]i inhibition, as demonstrated by a decrease in the expression of the ER stress markers 78 kDa glucose-regulated protein (GRP78) and 94 kDa glucose-regulated protein (GRP94) at both the mRNA and protein levels. Collectively, these data identified [Ca(2+)]i as a critical mediator of the pathological changes that occur in mandibular cartilage under compressive mechanical force and shed light on the treatment of mechanical stress-mediated cartilage degradation.

  13. Endoplasmic Reticulum Stress Instigates the Rotenone Induced Oxidative Apoptotic Neuronal Death: a Study in Rat Brain.

    PubMed

    Goswami, Poonam; Gupta, Sonam; Biswas, Joyshree; Sharma, Sharad; Singh, Sarika

    2016-10-01

    The present study was conducted to evaluate the involvement of endoplasmic reticulum stress in rotenone-induced oxidative neuronal death in rat brain. Rotenone (6 μg/3 μl) was administered intranigrally, unilaterally (right side) in SD rat brain. Neuronal morphology, expression level of tyrosine hydroxylase (TH) and endoplasmic reticulum (ER) stress markers like glucose-regulated protein 78 (GRP78), growth arrest and DNA damage-inducible gene 153 (GADD153), eukaryotic translation initiation factor 2α (p-eIF2α/eIF2α) and cleaved caspase-12 were estimated in the rat brain. Levels of reactive oxygen species (ROS), reduced glutathione (GSH) and enzymatic activities of glutathione peroxidase (GPx) and glutathione reductase (GRd) were estimated to assess the rotenone induced oxidative stress. Apoptotic death of neurons was assessed by estimating the mRNA level of caspase-3. Rotenone administration caused altered neuronal morphology, decreased expression of TH, augmented ROS level, decreased level of GSH and decreased activities of GPx and GRd enzymes which were significantly attenuated with the pretreatment of ER stress inhibitor, salubrinal (1 mg/kg, intraperitoneal). Significantly increased levels of GRP78, GADD, dephosphorylated eIF2α and cleaved caspase-12 was also observed after rotenone administration, which was inhibited with the pretreatment of salubrinal. Rotenone-induced increased mRNA level of caspase-3 was also attenuated by pretreatment of salubrinal. Findings suggested that salubrinal treatment significantly inhibited the rotenone-induced neurotoxicity implicating that ER stress initiates the rotenone-induced oxidative stress and neuronal death. PMID:26446018

  14. Golgi and endoplasmic reticulum functions take place in different subcellular compartments of Entamoeba histolytica.

    PubMed

    Bredeston, Luis M; Caffaro, Carolina E; Samuelson, John; Hirschberg, Carlos B

    2005-09-16

    Entamoeba histolytica is a protozoan parasite that causes dysentery in developing countries of Africa, Asia, and Latin America. The lack of a defined Golgi apparatus in E. histolytica as well as in other protists led to the hypothesis that they had evolved prior to the acquisition of such organelle even though glycoproteins, glycolipids, and antigens have been detected, the latter of which react with antibodies against Golgi apparatus proteins of higher eukaryotes. We here provide direct evidence for Golgi apparatus-like functions in E. histolytica as well as for components of glycoprotein folding quality control. Using a combination of bioinformatic, cell biological, and biochemical approaches we have (a) cloned and expressed the E. histolytica UDP-galactose transporter in Saccharomyces cerevisiae; its K(m) for UDP-galactose is 2.9 microm; (b) characterized vesicles in an extract of the above protist, which transport UDP-galactose into their lumen with a K(m) of 2.7 microm;(c) detected galactosyltransferase activity(ies) in the lumen of the above vesicles with the K(m) for UDP-galactose, using endogenous acceptors, being 93 microm;(d) measured latent apyrase activities in the above vesicles, suggesting they are in the lumen; (e) characterized UDP-glucose transport activities in Golgi apparatus and endoplasmic reticulum-like vesicles with K(m)s for UDP-glucose of approximately 2-4 microm. Although the endoplasmic reticulum-like fraction showed UDP-glucose: glycoprotein glucosyltransferase activity, the Golgi apparatus-like fraction did not. This fraction contained other glucosyltransferases. Together, these studies demonstrate that E. histolytica has different vesicles that play a role in protein glycosylation and folding quality control, analogous to the above organellar functions of higher eukaryotes.

  15. Sequestered endoplasmic reticulum space for sequential metabolism of salicylamide. Coupling of hydroxylation and glucuronidation.

    PubMed

    Tirona, R G; Pang, K S

    1996-08-01

    The metabolic disposition of simultaneously delivered [14C]salicylamide (SAM) (100 microM) and a tracer concentration of its hydroxylated metabolite [3H]gentisamide (GAM) was studied with single-pass followed by recirculating rat liver perfusion (10 ml/min). The use of dual radiolabeling of precursor-product pairs in single-pass and recirculating perfusions allowed for characterization of the differential metabolism of preformed [3H]GAM and formed [14C]GAM, which arose in situ in the liver with [14C]SAM single-pass perfusion, and the behavior of circulating [14C]GAM, which behaved as a preformed species in recirculation. In both modes of perfusion, [14C]SAM was mainly sequentially metabolized to [14C]GAM-5-glucuronide, whereas [3H]GAM predominantly formed [3H]GAM-5-sulfate. The steady-state and time-averaged clearances of SAM were identical and approached the value of flow, yielding a high hepatic extraction ratio (E = 0.98). The apparent extraction ratio of formed GAM [E(mi) = 0.96] was greater than that of the preformed species [E(pmi) approximately 0.7]. Because the coupling of (SAM) oxidation and (GAM) glucuronidation was a plausible explanation for the observation, a novel physiological pharmacokinetic model was developed to interpret the data. In this model, the liver was divided into three zonal units, within which acinar distribution of enzymatic activities was considered, namely periportal sulfation, evenly distributed glucuronidation, and perivenous hydroxylation. Each zonal region was subdivided into extracellular, cytosolic, and endoplasmic reticulum compartments, with cytosolic (sulfotransferases) and microsomal (cytochromes P-450 and UDP-glucuronosyltransferase) enzymes being segregated intracellularly into the cytosolic compartment and endoplasmic reticulum compartment, respectively. The simulations provided a good prediction of the present experimental data as well as previously obtained data with increasing SAM concentration and retrograde flow and

  16. ILDR2: An Endoplasmic Reticulum Resident Molecule Mediating Hepatic Lipid Homeostasis

    PubMed Central

    Watanabe, Kazuhisa; Millings, Elizabeth J.; Lefkowitch, Jay H.; Fischer, Stuart G.; LeDuc, Charles A.; Leibel, Rudolph L.

    2013-01-01

    Ildr2, a modifier of diabetes susceptibility in obese mice, is expressed in most organs, including islets and hypothalamus, with reduced levels in livers of diabetes-susceptible B6.DBA mice congenic for a 1.8 Mb interval of Chromosome 1. In hepatoma and neuronal cells, ILDR2 is primarily located in the endoplasmic reticulum membrane. We used adenovirus vectors that express shRNA or are driven by the CMV promoter, respectively, to knockdown or overexpress Ildr2 in livers of wild type and ob/ob mice. Livers in knockdown mice were steatotic, with increased hepatic and circulating triglycerides and total cholesterol. Increased circulating VLDL, without reduction in triglyceride clearance suggests an effect of reduced hepatic ILDR2 on hepatic cholesterol clearance. In animals that overexpress Ildr2, hepatic triglyceride and total cholesterol levels were reduced, and strikingly so in ob/ob mice. There were no significant changes in body weight, energy expenditure or glucose/insulin homeostasis in knockdown or overexpressing mice. Knockdown mice showed reduced expression of genes mediating synthesis and oxidation of hepatic lipids, suggesting secondary suppression in response to increased hepatic lipid content. In Ildr2-overexpressing ob/ob mice, in association with reduced liver fat content, levels of transcripts related to neutral lipid synthesis and cholesterol were increased, suggesting “relief” of the secondary suppression imposed by lipid accumulation. Considering the fixed location of ILDR2 in the endoplasmic reticulum, we investigated the possible participation of ILDR2 in ER stress responses. In general, Ildr2 overexpression was associated with increases, and knockdown with decreases in levels of expression of molecular components of canonical ER stress pathways. We conclude that manipulation of Ildr2 expression in liver affects both lipid homeostasis and ER stress pathways. Given these reciprocal interactions, and the relatively extended time-course over

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

    SciTech Connect

    Isomura, Midori; Kotake, Yaichiro Masuda, Kyoichi; Miyara, Masatsugu; Okuda, Katsuhiro; Samizo, Shigeyoshi; Sanoh, Seigo; Hosoi, Toru; Ozawa, Koichiro; Ohta, Shigeru

    2013-10-01

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

  18. Intermittent selective clamping improves rat liver regeneration by attenuating oxidative and endoplasmic reticulum stress.

    PubMed

    Ben Mosbah, I; Duval, H; Mbatchi, S-F; Ribault, C; Grandadam, S; Pajaud, J; Morel, F; Boudjema, K; Compagnon, P; Corlu, A

    2014-01-01

    Intermittent clamping of the portal trial is an effective method to avoid excessive blood loss during hepatic resection, but this procedure may cause ischemic damage to liver. Intermittent selective clamping of the lobes to be resected may represent a good alternative as it exposes the remnant liver only to the reperfusion stress. We compared the effect of intermittent total or selective clamping on hepatocellular injury and liver regeneration. Entire hepatic lobes or only lobes to be resected were subjected twice to 10 min of ischemia followed by 5 min of reperfusion before hepatectomy. We provided evidence that the effect of intermittent clamping can be damaging or beneficial depending to its mode of application. Although transaminase levels were similar in all groups, intermittent total clamping impaired liver regeneration and increased apoptosis. In contrast, intermittent selective clamping improved liver protein secretion and hepatocyte proliferation when compared with standard hepatectomy. This beneficial effect was linked to better adenosine-5'-triphosphate (ATP) recovery, nitric oxide production, antioxidant activities and endoplasmic reticulum adaptation leading to limit mitochondrial damage and apoptosis. Interestingly, transient and early chaperone inductions resulted in a controlled activation of the unfolded protein response concomitantly to endothelial nitric oxide synthase, extracellular signal-regulated kinase-1/2 (ERK1/2) and p38 MAPK activation that favors liver regeneration. Endoplasmic reticulum stress is a central target through which intermittent selective clamping exerts its cytoprotective effect and improves liver regeneration. This procedure could be applied as a powerful protective modality in the field of living donor liver transplantation and liver surgery. PMID:24603335

  19. Genome-wide analysis of tunicamycin-induced endoplasmic reticulum stress response and the protective effect of endoplasmic reticulum inhibitors in neonatal rat cardiomyocytes.

    PubMed

    Liu, Chun-Lei; Zhong, Wu; He, Yun-Yun; Li, Xin; Li, Song; He, Kun-Lun

    2016-02-01

    Tunicamycin (TM) is an inducer of endoplasmic reticulum (ER) stress. However, which genes related to ER stress was induced in cardiomyocytes on a genome-wide scale remains poorly understood. Salubrinal and its derivatives are ER stress inhibitors. However, the cellular protection mechanisms remain unresolved. Neonatal rat cardiomyocytes were cultured from ventricles of one-day-old Wistar rats. Cells were exposed to salubrinal, its derivatives (PP1-12, PP1-24) or vehicle followed by TM treatment at different times. Total RNA was isolated from cells for RNA-sequencing analysis. The expressions of 189, 182, 556, 860, and 1314 genes were changed in cells exposed to TM for 1, 3, 6, 12, and 24 h. Five well-known UPR genes (Hspa5, Hsp90b1, Calr, Ddit3, and Atf4) were significantly increased in a time-dependent manner. Six not well-known genes (Hyou1, Herpud1, Manf, Creld2, Sdf2l1, and Slc3a2) were highlighted to be involved in ER stress. Compared with TM-only treated cells, the expressions of 36 genes upregulated by TM and 74 genes downregulated by TM were reversed by salubrinal. In comparison, 121 genes upregulated by TM and 92 genes downregulated by TM were reversed by PP1-12. Most genes altered by salubrinal are in the category of transcription (1 h) and cell cycle (24 h). Most genes altered by PP1-12 are in the category of response to ER stress (3 h) and cell cycle (24 h). Our findings help elucidate the mechanism for TM treatment and may be useful for future drug screens involved in ER stress. PMID:26738490

  20. Outpatient competence restoration: A model and outcomes

    PubMed Central

    Johnson, Nicole R; Candilis, Philip J

    2015-01-01

    AIM: To describe a model outpatient competence restoration program (OCRP) and provide data on time to restoration of adjudicative competence. METHODS: The authors tracked the process by which individuals are referred for outpatient competence restoration (OCR) by courts in the United States capital, describing the unique requirements of American law, and the avenues available for compelling adherence. Competence to stand trial is a critical gate-keeping function of the judicial and forensic communities and assures that defendants understand courtroom procedures. OCR is therefore an effort to assure fairness and protection of important legal rights. Multi-media efforts are described that educate patients and restore competence to stand trial. These include resources such as group training, use of licensed clinicians, visual aids, structured instruments, and cinema. Aggregate data from the OCRP’s previous 4 years of OCR efforts were reviewed for demographic characteristics, restoration rate, and time to restoration. Poisson regression modeling identified the differences in restoration between sequential 45-d periods after entrance into the program. RESULTS: In the past 4 years, the DC OCRP has been successful in restoring 55 of 170 participants (32%), with an average referral rate of 35 persons per year. 76% are restored after the initial 45 d in the program. Demographics of the group indicate a predominance of African-American men with a mean age of 42. Thought disorders predominate and individuals in care face misdemeanor charges 78% of the time. Poisson regression modeling of the number attaining competence during four successive 45-d periods showed a substantial difference among the time periods for the rate of attaining competence (P = 0.0011). The three time periods after 45 d each showed a significant decrease in the restoration rate when compared to the initial 0 to 45 d period - their relative rates were only 22% to 33% as high as the rate for 0-45 d (all