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Sample records for organized smooth endoplasmic

  1. Direct observation of molecular arrays in the organized smooth endoplasmic reticulum.

    PubMed

    Korkhov, Vladimir M; Zuber, Benoît

    2009-08-24

    Tubules and sheets of endoplasmic reticulum perform different functions and undergo inter-conversion during different stages of the cell cycle. Tubules are stabilized by curvature inducing resident proteins, but little is known about the mechanisms of endoplasmic reticulum sheet stabilization. Tethering of endoplasmic reticulum membranes to the cytoskeleton or to each other has been proposed as a plausible way of sheet stabilization. Here, using fluorescence microscopy we show that the previously proposed mechanisms, such as membrane tethering via GFP-dimerization or coiled coil protein aggregation do not explain the formation of the calnexin-induced organized smooth endoplasmic reticulum membrane stacks. We also show that the LINC complex proteins known to serve a tethering function in the nuclear envelope are excluded from endoplasmic reticulum stacks. Finally, using cryo-electron microscopy of vitreous sections methodology that preserves cellular architecture in a hydrated, native-like state, we show that the sheet stacks are highly regular and may contain ordered arrays of macromolecular complexes. Some of these complexes decorate the cytosolic surface of the membranes, whereas others appear to span the width of the cytosolic or luminal space between the stacked sheets. Our results provide evidence in favour of the hypothesis of endoplasmic reticulum sheet stabilization by intermembrane tethering.

  2. 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

  3. A VAPB mutant linked to amyotrophic lateral sclerosis generates a novel form of organized smooth endoplasmic reticulum.

    PubMed

    Fasana, Elisa; Fossati, Matteo; Ruggiano, Annamaria; Brambillasca, Silvia; Hoogenraad, Casper C; Navone, Francesca; Francolini, Maura; Borgese, Nica

    2010-05-01

    VAPB (vesicle-associated membrane protein-associated protein B) is an endoplasmic reticulum (ER)-resident tail-anchored adaptor protein involved in lipid transport. A dominantly inherited mutant, P56S-VAPB, causes a familial form of amyotrophic lateral sclerosis (ALS) and forms poorly characterized inclusion bodies in cultured cells. To provide a cell biological basis for the understanding of mutant VAPB pathogenicity, we investigated its biogenesis and the inclusions that it generates. Translocation assays in cell-free systems and in cultured mammalian cells were used to investigate P56S-VAPB membrane insertion, and the inclusions were characterized by confocal imaging and electron microscopy. We found that mutant VAPB inserts post-translationally into ER membranes in a manner indistinguishable from the wild-type protein but that it rapidly clusters to form inclusions that remain continuous with the rest of the ER. Inclusions were induced by the mutant also when it was expressed at levels comparable to the endogenous wild-type protein. Ultrastructural analysis revealed that the inclusions represent a novel form of organized smooth ER (OSER) consisting in a limited number of parallel cisternae (usually 2 or 3) interleaved by a approximately 30 nm-thick electron-dense cytosolic layer. Our results demonstrate that the ALS-linked VAPB mutant causes dramatic ER restructuring that may underlie its pathogenicity in motoneurons.

  4. Birbeck Granule-Like “Organized Smooth Endoplasmic Reticulum” Resulting from the Expression of a Cytoplasmic YFP-Tagged Langerin

    PubMed Central

    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

  5. Crystalloid smooth endoplasmic reticulum in the quail uropygial gland.

    PubMed

    Fringes, B; Gorgas, K

    1993-06-01

    The occurrence, localization and organization of crystalloid smooth endoplasmic reticulum (SER) membrane aggregates in the male quail uropygial gland was investigated by electron microscopy. The lattice-like structures exhibiting a hexagonal honeycomb pattern are regularly found in the perinuclear region of the fully developed intermediate cell (type II) which is most effective in lipid biosynthesis and constitutes the middle layers of the stratified glandular epithelium undergoing sebaceous transformation. The crystalloids frequently exhibit a rectangular shape and tend to cluster, the latter exceeding 5 microns in length. They are composed of sets of highly ordered and densely packed tubular SER profiles. Diaminobenzidine (DAB) stained peroxisomes exhibit a close spatial relationship to the borders of crystalloids, but the organelles do not participate in the formation of these grid-like structures. The functional significance of the conformational change of the SER organization is not known. Local accumulation of specific lipogenic enzymes within this functional SER domain is discussed.

  6. 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.

  7. 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.

  8. Structural organization of the endoplasmic reticulum

    PubMed Central

    Voeltz, Gia K.; Rolls, Melissa M.; Rapoport, Tom A.

    2002-01-01

    The endoplasmic reticulum (ER) is a continuous membrane system but consists of various domains that perform different functions. Structurally distinct domains of this organelle include the nuclear envelope (NE), the rough and smooth ER, and the regions that contact other organelles. The establishment of these domains and the targeting of proteins to them are understood to varying degrees. Despite its complexity, the ER is a dynamic structure. In mitosis it must be divided between daughter cells and domains must be re-established, and even in interphase it is constantly rearranged as tubules extend along the cytoskeleton. Throughout these rearrangements the ER maintains its basic structure. How this is accomplished remains mysterious, but some insight has been gained from in vitro systems. PMID:12370207

  9. 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.

  10. Oocytes affected by smooth endoplasmic reticulum aggregates: to discard or not to discard?

    PubMed

    Shaw-Jackson, Chloë; Thomas, Anne-Laure; Van Beirs, Nina; Ameye, Lieveke; Colin, Jérôme; Bertrand, Evelyne; Becker, Bénédicte; Rozenberg, Serge; Autin, Candice

    2016-07-01

    Oocytes containing smooth endoplasmic reticulum aggregates (SERa) have been associated with reduced fertilization and clinical pregnancy rates as well as compromised neonatal outcomes. It was therefore recommended by an Alpha-ESHRE Consensus to discard oocytes presenting this dysmorphism. The data in the literature are nevertheless conflicting and healthy babies have recently been obtained from affected oocytes. The objectives of this study were to compare clinical outcomes between ICSI cycles with and without oocytes affected by smooth endoplasmic reticulum aggregates and to confirm whether affected oocytes can produce healthy babies. A prospective observational study was performed comparing 714 SERa- ICSI cycles to 112 SERa+ cycles. Among the SERa+ cycles, 518 SERa- oocytes and 213 SERa+ oocytes were analyzed. Fertilization, embryo quality, and pregnancy rates as well as neonatal outcomes were compared between SERa+ and SERa- cycles as well as between SERa+ and SERa- oocytes. The presence of SERa was not associated with an adverse effect on embryological, clinical or neonatal data for SERa+ cycles and oocytes. Seven healthy babies were born from embryos originating from SERa+ oocytes. These results are encouraging and might contribute in the future to a revision of the Alpha-ESHRE Consensus. Larger studies, including a correlation between frequency and size of SERa, clinical outcomes and malformation rates, as well as the follow-up of babies born are nevertheless necessary. In the meantime, the currently conflicting data requires caution when considering transfers of embryos affected by SERa.

  11. 4-Phenylbutyric Acid Reveals Good Beneficial Effects on Vital Organ Function via Anti-Endoplasmic Reticulum Stress in Septic Rats.

    PubMed

    Liu, Liangming; Wu, Huiling; Zang, JiaTao; Yang, Guangming; Zhu, Yu; Wu, Yue; Chen, Xiangyun; Lan, Dan; Li, Tao

    2016-08-01

    Sepsis and septic shock are the common complications in ICUs. Vital organ function disorder contributes a critical role in high mortality after severe sepsis or septic shock, in which endoplasmic reticulum stress plays an important role. Whether anti-endoplasmic reticulum stress with 4-phenylbutyric acid is beneficial to sepsis and the underlying mechanisms are not known. Laboratory investigation. State Key Laboratory of Trauma, Burns and Combined Injury. Sprague-Dawley rats. Using cecal ligation and puncture-induced septic shock rats, lipopolysaccharide-treated vascular smooth muscle cells, and cardiomyocytes, effects of 4-phenylbutyric acid on vital organ function and the relationship with endoplasmic reticulum stress and endoplasmic reticulum stress-mediated inflammation, apoptosis, and oxidative stress were observed. Conventional treatment, including fluid resuscitation, vasopressin, and antibiotic, only slightly improved the hemodynamic variable, such as mean arterial blood pressure and cardiac output, and slightly improved the vital organ function and the animal survival of septic shock rats. Supplementation of 4-phenylbutyric acid (5 mg/kg; anti-endoplasmic reticulum stress), especially administered at early stage, significantly improved the hemodynamic variables, vital organ function, such as liver, renal, and intestinal barrier function, and animal survival in septic shock rats. 4-Phenylbutyric acid application inhibited the endoplasmic reticulum stress and endoplasmic reticulum stress-related proteins, such as CCAAT/enhancer-binding protein homologous protein in vital organs, such as heart and superior mesenteric artery after severe sepsis. Further studies showed that 4-phenylbutyric acid inhibited endoplasmic reticulum stress-mediated cytokine release, apoptosis, and oxidative stress via inhibition of nuclear factor-κB, caspase-3 and caspase-9, and increasing glutathione peroxidase and superoxide dismutase expression, respectively. Anti-endoplasmic

  12. Endoplasmic reticulum stress in arterial smooth muscle cells: A novel regulator of vascular disease.

    PubMed

    Furmanik, Malgorzata; Shanahan, Catherine M

    2016-10-13

    Cardiovascular disease continues to be the leading cause of death in industrialised societies. The idea that the arterial smooth muscle cell (ASMC) plays a key role in regulating many vascular pathologies has been gaining importance, as has the realisation that not enough is known about the pathological cellular mechanisms regulating ASMC function in vascular remodelling. In the past decade endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) have been recognised as a stress response underlying many physiological and pathological processes in various vascular cell types. Here we summarize what is known about how ER stress signalling regulates phenotypic switching, trans/dedifferentiation and apoptosis of ASMCs and contributes to atherosclerosis, hypertension, aneurysms and vascular calcification.

  13. Deliveries of babies with normal health derived from oocytes with smooth endoplasmic reticulum clusters.

    PubMed

    Hattori, Hiromitsu; Nakamura, Yusuke; Nakajo, Yukiko; Araki, Yasuhisa; Kyono, Koichi

    2014-11-01

    To examine the impact on development of derived embryos from smooth endoplasmic reticulum clusters (SERC) in human metaphase II (MII) oocytes. Retrospective analysis at Kyono ART Clinic. Comparison of embryological development, pregnancy, live birth and fetal malformation between oocytes with SERC (the SERC(+) group) and those without (the SERC(-) group) in 2,158 patients (3,758 cycles) after ICSI. Fertilization and implantation rate were significantly lower in SERC(+) MII oocytes than in SERC(-) MII oocytes. After the transfer of fresh and vitrified embryos derived from SERC(+) oocytes, 14 pregnancies resulted in 14 healthy babies, including 2 from fresh embryo transfer (ET) and 12 from vitrified-warmed ET, with no malformations. The presence of SERC in MII oocytes was associated with significantly lower fertilization rates and implantation rates than seen in SERC(-) MII oocytes within SERC (+) cycles. However, SERC had no impact on post-implantation development as well as neonatal outcome.

  14. Smooth endoplasmic reticulum aggregations in all retrieved oocytes causing recurrent multiple anomalies: case report.

    PubMed

    Akarsu, Cem; Cağlar, Gamze; Vicdan, Kubilay; Sözen, Eran; Biberoğlu, Kutay

    2009-10-01

    To document the relationship between smooth endoplasmic reticulum (SER) aggregations and recurrent fetal anomalies. Case report. Private IVF center. A 28-year-old woman with an 11-year history of primary infertility. Three consecutive cycles of intracytoplasmic sperm injection (ICSI) in the same patient. Clinical pregnancy, live birth, fetal anomaly. In three consecutive ICSI cycles, a total of 59 MII oocytes were retreived in the same patient, all displaying SER aggregations. The fertilization rate per cycle was 80%, 50%, and 42%, respectively. A total of 12 embryos were transferred in three ICSI cycles, of which 11 were grade 1 embryos. Two of the three cycles ended up with clinical ongoing pregnancies but with multiple fetal anomalies. This is the first case reported with SER aggregations in all retrieved oocytes in three consecutive ICSI cycles. The repetetive multiple fetal anomalies possibly related to oocyte dysmorphism are of concern.

  15. Endoplasmic Reticulum Stress in Arterial Smooth Muscle Cells: A Novel Regulator of Vascular Disease

    PubMed Central

    Furmanik, Malgorzata; Shanahan, Catherine M.

    2017-01-01

    Cardiovascular disease continues to be the leading cause of death in industrialised societies. The idea that the arterial smooth muscle cell (ASMC) plays a key role in regulating many vascular pathologies has been gaining importance, as has the realisation that not enough is known about the pathological cellular mechanisms regulating ASMC function in vascular remodelling. In the past decade endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) have been recognised as a stress response underlying many physiological and pathological processes in various vascular cell types. Here we summarise what is known about how ER stress signalling regulates phenotypic switching, trans/dedifferentiation and apoptosis of ASMCs and contributes to atherosclerosis, hypertension, aneurysms and vascular calcification.

  16. Can healthy babies originate from oocytes with smooth endoplasmic reticulum aggregates? A systematic mini-review.

    PubMed

    Shaw-Jackson, Chloë; Van Beirs, Nina; Thomas, Anne-Laure; Rozenberg, Serge; Autin, Candice

    2014-07-01

    Is it time to reconsider whether oocytes affected by smooth endoplasmic reticulum aggregates (SERa) should still be destroyed? At the time of writing, the literature shows that 171 apparently healthy babies have been born from SERa+ cycles amongst which 22 were from SERa+ oocytes. The SER dysmorphism has been associated with negative embryological, clinical and neonatal outcomes, which led to a recommendation in 2011 to avoid inseminating affected oocytes. The data in the literature are nevertheless conflicting and some centres have continued using SERa+ oocytes. A systematic mini-review of the literature to 7 November 2013 was performed with the keywords 'Smooth Endoplasmic Reticulum' and 'oocyte', limited to humans and written in English. Articles (Pubmed) and major abstracts where the effect of the SER dysmorphism was studied as an individual feature on embryological, clinical or neonatal outcomes were included in this review. From a total of 297 publications identified, 13 were selected as being relevant to this review. One hundred eighty-three babies have been reported to be born from SERa+ cycles, 171 were healthy, 8 live births presented malformations, 3 were neonatal deaths, 1 was a stillborn and additionally 4 terminations of pregnancy occurred. Data concerning SERa+ oocytes in the literature are scarce, the studies are small, heterogeneous and results are conflicting. The malformations observed could be due to over-reporting of scattered alarming results. Alternatively, an under-reporting of complications cannot be excluded. Centres that have or that are including transfers of SERa+ embryos in their IVF procedures should publish their clinical and neonatal outcomes as well as the follow-up of children. The birth of healthy babies from SERa+ embryos is encouraging and might lead in the future to a revision of the current consensus on the SER dysmorphism. Further research is needed to understand the origin of this dysmorphism and help avoid its occurrence

  17. Distinct mechanisms controlling rough and smooth endoplasmic reticulum contacts with mitochondria.

    PubMed

    Wang, Peter T C; Garcin, Pierre O; Fu, Min; Masoudi, Matthew; St-Pierre, Pascal; Panté, Nelly; Nabi, Ivan R

    2015-08-01

    Gp78 (also known as AMFR), an endoplasmic-reticulum (ER)-associated protein degradation (ERAD) E3 ubiquitin ligase, localizes to mitochondria-associated ER and targets the mitofusin (Mfn1 and Mfn2) mitochondrial fusion proteins for degradation. Gp78 is also the cell surface receptor for autocrine motility factor (AMF), which prevents Gp78-dependent mitofusin degradation. Gp78 ubiquitin ligase activity promotes ER-mitochondria association and ER-mitochondria Ca(2+) coupling, processes that are reversed by AMF. Electron microscopy of HT-1080 fibrosarcoma cancer cells identified both smooth ER (SER; ∼8 nm) and wider (∼50-60 nm) rough ER (RER)-mitochondria contacts. Both short hairpin RNA (shRNA)-mediated knockdown of Gp78 (shGp78) and AMF treatment selectively reduced the extent of RER-mitochondria contacts without impacting on SER--mitochondria contacts. Concomitant small interfering RNA (siRNA)-mediated knockdown of Mfn1 increased SER-mitochondria contacts in both control and shGp78 cells, whereas knockdown of Mfn2 increased RER-mitochondria contacts selectively in shGp78 HT-1080 cells. The mitofusins therefore inhibit ER-mitochondria interaction. Regulation of close SER-mitochondria contacts by Mfn1 and of RER-mitochondria contacts by AMF-sensitive Gp78-mediated degradation of Mfn2 define new mechanisms that regulate ER-mitochondria interactions.

  18. Ultrastructure of tubular smooth endoplasmic reticulum aggregates in human metaphase II oocytes and clinical implications.

    PubMed

    Sá, Rosália; Cunha, Mariana; Silva, Joaquina; Luís, Ana; Oliveira, Cristiano; Teixeira da Silva, José; Barros, Alberto; Sousa, Mário

    2011-07-01

    To compare demographic, embryologic, pregnancy, and newborn outcomes after intracytoplasmic sperm injection (ICSI) cycles with or without mature oocytes (metaphase II [MII]) showing visible aggregates of tubular smooth endoplasmic reticulum (aSERT) and to describe the ultrastructure of this dysmorphism. Retrospective study. Private fertility center and university cell biology and genetics departments. There were 721 ICSI cycles, 520 carrying morphologically normal MII (control group) and 60 containing aSERT-MII (study group). None. Embryologic and clinical and live birth outcomes, including malformations and ultrastructural characterization of aSERT-MII. Compared with the control group there was a significant decrease in the fertilization, embryo cleavage, and blastocyst rates in the study group. The only child born after transfer of embryos derived from aSERT-MII presented a major cardiovascular malformation. Ultrastructurally, large aSERT were surrounded by abnormal-shaped mitochondria and clusters of small dense bodies formed by very small vesicles, and they had curvilinear dense tubules in the interior. The same pathology was observed in small peripheral aSERT. The presence of large aSERT, showing attainment of the periphery, demonstrated that the cytoplasm is pathologic. The compromised embryo development and implantation was associated with decreased clinical outcomes and newborn malformations. Therefore, oocytes with large aSERT should not be used for embryo transfer. Copyright © 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  19. Policy of IVF centres towards oocytes affected by Smooth Endoplasmic Reticulum aggregates: a multicentre survey study.

    PubMed

    Van Beirs, Nina; Shaw-Jackson, Chloë; Rozenberg, Serge; Autin, Candice

    2015-06-01

    The presence of Smooth Endoplasmic Reticulum aggregates (SERa) has been reported to be associated with adverse outcomes. An Alpha-ESHRE Consensus was published in 2011, strongly recommending to not inseminating affected oocytes. On the other hand, healthy babies have been born from oocytes presenting this dysmorphism. We surveyed several European IVF centres, to assess their attitudes concerning affected oocytes. This survey is based on a computer format and includes questions regarding the fate of affected oocytes. About 14 % of centres who answered our survey discard SERa+ oocytes. 43 % of centres that do not discard the oocytes, register and follow up neonatal data. About a quarter of centres inform their patients about this dysmorphism. Half of them require an informed consent prior to transferring affected embryos. Twenty-one centres reported having SERa+ births, with one reporting a malformation. 48 % of centres declared having been influenced by the Alpha-ESHRE Consensus, in their management policy of SERa+ oocytes. Few centres scrupulously respect the recommendations of the Alpha-ESHRE Consensus and discard affected oocytes. Since it is essential to determine if there truly is an impact of this dysmorphism and whether the guidelines are still valid, transfer of affected embryos should only be done when accompanied with data recording and monitoring of all foetal malformations from IVF. Clarifying the situation will allow IVF centres to correctly inform patients about the risk of birth malformations as well as whether a decreased chance of pregnancy exists.

  20. Cortistatin inhibits calcification of vascular smooth muscle cells by depressing osteoblastic differentiation and endoplasmic reticulum stress.

    PubMed

    Liu, Yue; Lin, Fang; Fu, Yu; Chen, Wenjia; Liu, Wenxiu; Chi, Jinyu; Zhang, Xiaohui; Yin, Xinhua

    2016-11-01

    Accumulating evidence has indicated that vascular smooth muscular cells (VSMCs) play an important role in the development of vascular calcification (VC). Cortistatin (CST), a novel bio-active peptide, has been shown to exert multiple protective effects on the cardiovascular system. However, the role and possible mechanism of CST in VC remain unclear. Therefore, we used β-glycerophosphoric acid (β-GP) to induce calcification in rat and human VSMCs to determine the effects of CST on osteoblastic differentiation and VSMC mineralization in vitro. Compared with the control, β-GP significantly increased alkaline phosphatase (ALP) activity and calcium content in cultured rat and human VSMCs, as well as multicellular node formation and calcium deposition, as confirmed by von Kossa and Alizarin Red S staining assays. After incubating rat and human VSMCs with β-GP in the presence of different doses of CST (10(-8) or 10(-7) mol/L), CST clearly reversed the β-GP-induced increases in ALP activity and calcium content and formation of pathological calcified nodes of VSMCs in a dose-independent manner. Moreover, 10(-8) and 10(-7) mol/L CST inhibited the phenotypic transformation of VSMCs into osteoblastic cells by decreasing the osteocalcin protein levels, increasing the SM-α-actin protein levels, and reducing endoplasmic reticulum stress by decreasing the protein expression of glucose-regulated protein 94 and CCAAT/enhancer-binding protein homologous protein. In conclusion, CST directly inhibited β-GP-induced calcification of VSMCs in vitro, probably by suppressing ERS and phenotypic transformation of VSMCs into osteoblastic cells. These results indicate that CST represents a potential target for the prevention and treatment of VC.

  1. GFP-LC3 labels organised smooth endoplasmic reticulum membranes independently of autophagy.

    PubMed

    Korkhov, Vladimir M

    2009-05-01

    Disruption of autophagy leads to accumulation of intracellular multilamellar inclusions morphologically similar to organised smooth endoplasmic reticulum (OSER) membranes. However, the relation of these membranous compartments to autophagy is unknown. The purpose of this study was to test whether OSER plays a role in the autophagic protein degradation pathway. Here, GFP-LC3 is shown to localise to the OSER membranes induced by calnexin expression both in transiently transfected HEK293 cells and in mouse embryo fibroblasts. In contrast to GFP-LC3, endogenous LC3 is excluded from these membranes under normal conditions as well as after cell starvation. Furthermore, YFP-Atg5, a protein essential for autophagy and known to reside on autophagic membranes, is excluded from the calnexin-positive inclusion structures. In cells devoid of Atg5, a protein essential for autophagy and known to reside on autophagic membranes, colocalisation of calnexin with GFP-LC3 within the multilamellar bodies is preserved. I show that calnexin, a protein enriched in the OSER, is not subject to autophagic or lysosomal degradation. Finally, GFP-LC3 targeting to these membranes is independent of its processing and insensitive to drugs modulating autophagic and lysosomal protein degradation. These observations are inconsistent with a role of autophagic/lysosomal degradation in clearance of multilamellar bodies comprising OSER. Furthermore, GFP-LC3, a fusion protein widely used as a marker for autophagic vesicles and pre-autophagic compartments, may be trapped in this compartment and this artefact must be taken into account if the construct is used to visualise autophagic membranes.

  2. Oocytes with smooth endoplasmic reticulum clusters originate blastocysts with impaired implantation potential.

    PubMed

    Setti, Amanda Souza; Figueira, Rita Cássia Sávio; de Almeida Ferreira Braga, Daniela Paes; Azevedo, Matheus de Castro; Iaconelli, Assumpto; Borges, Edson

    2016-12-01

    To study whether embryos derived from oocytes presenting a smooth endoplasmic reticulum cluster (SERC) are less likely to develop into blastocysts and implant. Transversal study. Private university-affiliated in vitro fertilization (IVF) center. Total of 7,609 oocytes obtained from 743 intracytoplasmic sperm injection (ICSI) cycles. Oocytes split between the SERC-positive cycles (with at least one SERC-positive oocyte) and the SERC-negative cycles (only oocytes free of SERC). Embryo implantation. A statistically significantly higher mean number of follicles (24.0 ± 10.5 vs. 19.6 ± 10.5), retrieved oocytes (17.8 ± 8.3 vs. 14.3 ± 8.0), and mature oocytes (13.5 ± 6.2 vs. 10.6 ± 5.9) were observed in the SERC-positive cycles as compared with SERC-negative cycles. The implantation rate was statistically significantly lower in SERC-positive cycles as compared with SERC-negative cycles (14.8% vs. 25.6%; odds ratio 0.61; 95% confidence interval, 0.44-0.86). When only cycles with in which none (0) or all the blastocysts transferred had implanted (100%) were analyzed, the mean implantation rate per transferred blastocyst in the SERC-negative group was 20.5%; no blastocysts derived from SERC-positive oocytes implanted. The occurrence of SERC impairs embryo implantation. Careful oocyte observation that takes into account the presence of SERC should be part of embryo selection strategy before transfer. Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  3. [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.

  4. Peroxynitrite resistance of sarco/endoplasmic reticulum Ca2+ pump in pig coronary artery endothelium and smooth muscle.

    PubMed

    Schmidt, Tracey; Zaib, Farhah; Samson, Sue E; Kwan, Chiu-Yin; Grover, Ashok K

    2004-07-01

    We examined the effects of peroxynitrite pre-treatment on sarco/endoplasmic reticulum Ca(2+) (SERCA) pump in pig coronary artery smooth muscle and endothelium. In saponin-permeabilized cells, smooth muscle showed much greater rates of the SERCA Ca(2+) pump-dependent (45)Ca(2+) uptake/mg protein than did the endothelial cells. Peroxynitrite treatment of cells inhibited the SERCA pump more severely in smooth muscle cells than in endothelial cells. To determine implications of this observation, we next examined the effect of the SERCA pump inhibitor cyclopiazonic acid (CPA) on intracellular Ca(2+) concentration of intact cultured cells. CPA produced cytosolic Ca(2+) transients in cultured endothelial and smooth muscle cells. Pre-treatment with peroxynitrite (200 microM) inhibited the Ca(2+) transients in the smooth muscle but not in the endothelial cells. CPA contracts de-endothelialized artery rings and relaxes precontracted arteries with intact endothelium. Peroxynitrite (250 microM) pre-treatment inhibited contraction in the de-endothelialized artery rings, but not the endothelium-dependent relaxation. Thus, endothelial cells appear to be more resistant than smooth muscle to the effects of peroxynitrite at the levels of SERCA pump activity, CPA-induced Ca(2+) transients in cultured cells, and the effects of CPA on contractility. The greater resistance of endothelium to peroxynitrite may play a protective role in pathological conditions such as ischemia-reperfusion when excess free radicals are produced.

  5. Bone morphogenetic protein-2 activates NADPH oxidase to increase endoplasmic reticulum stress and human coronary artery smooth muscle cell calcification.

    PubMed

    Liberman, Marcel; Johnson, Rebecca C; Handy, Diane E; Loscalzo, Joseph; Leopold, Jane A

    2011-09-30

    Bone morphogenetic protein-2 (BMP-2) increases oxidant stress and endoplasmic reticulum (ER) stress to stimulate differentiation of osteoblasts; however, the role of these signaling pathways in the transition of smooth muscle cells to a calcifying osteoblast-like phenotype remains incompletely characterized. We, therefore, treated human coronary artery smooth muscle cells (HCSMC) with BMP-2 (100ng/mL) and found an increase in NADPH oxidase activity and oxidant stress that occurred via activation of the bone morphogenetic protein receptor 2 and Smad 1 signaling. BMP-2-mediated oxidant stress also increased endoplasmic reticulum (ER) stress demonstrated by increased expression of GRP78, phospho-IRE1α, and the transcription factor XBP1. Analysis of a 1kb segment of the Runx2 promoter revealed an XBP1 binding site; electrophoretic mobility shift and chromatin immunoprecipitation assays demonstrated that XBP1 bound to the Runx2 promoter at this site in BMP-2-treated HCSMC. Inhibition of oxidant stress or ER stress decreased Runx2 expression, intracellular calcium deposition, and mineralization of BMP-2-treated HCSMC. Thus, in HCSMC, BMP-2 increases oxidant stress and ER stress to increase Runx2 expression and promote vascular smooth muscle cell calcification. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Role of syntaxin 18 in the organization of endoplasmic reticulum subdomains.

    PubMed

    Iinuma, Takayuki; Aoki, Takehiro; Arasaki, Kohei; Hirose, Hidenori; Yamamoto, Akitsugu; Samata, Rie; Hauri, Hans-Peter; Arimitsu, Nagisa; Tagaya, Mitsuo; Tani, Katsuko

    2009-05-15

    The presence of subdomains in the endoplasmic reticulum (ER) enables this organelle to perform a variety of functions, yet the mechanisms underlying their organization are poorly understood. In the present study, we show that syntaxin 18, a SNAP (soluble NSF attachment protein) receptor localized in the ER, is important for the organization of two ER subdomains, smooth/rough ER membranes and ER exit sites. Knockdown of syntaxin 18 caused a global change in ER membrane architecture, leading to the segregation of the smooth and rough ER. Furthermore, the organization of ER exit sites was markedly changed concomitantly with dispersion of the ER-Golgi intermediate compartment and the Golgi complex. These morphological changes in the ER were substantially recovered by treatment of syntaxin-18-depleted cells with brefeldin A, a reagent that stimulates retrograde membrane flow to the ER. These results suggest that syntaxin 18 has an important role in ER subdomain organization by mediating the fusion of retrograde membrane carriers with the ER membrane.

  7. Synergistic role of protein phosphatase inhibitor 1 and sarco/endoplasmic reticulum Ca2+ -ATPase in the acquisition of the contractile phenotype of arterial smooth muscle cells.

    PubMed

    Lipskaia, Larissa; Bobe, Regis; Chen, Jiqiu; Turnbull, Irene C; Lopez, Jose J; Merlet, Elise; Jeong, Dongtaq; Karakikes, Ioannis; Ross, Alexandra S; Liang, Lifan; Mougenot, Nathalie; Atassi, Fabrice; Lompré, Anne-Marie; Tarzami, Sima T; Kovacic, Jason C; Kranias, Evangelia; Hajjar, Roger J; Hadri, Lahouaria

    2014-02-18

    Phenotypic modulation or switching of vascular smooth muscle cells from a contractile/quiescent to a proliferative/synthetic phenotype plays a key role in vascular proliferative disorders such as atherosclerosis and restenosis. Although several calcium handling proteins that control differentiation of smooth muscle cells have been identified, the role of protein phosphatase inhibitor 1 (I-1) in the acquisition or maintenance of the contractile phenotype modulation remains unknown. In human coronary arteries, I-1 and sarco/endoplasmic reticulum Ca2+ -ATPase expression is specific to contractile vascular smooth muscle cells. In synthetic cultured human coronary artery smooth muscle cells, protein phosphatase inhibitor 1 (I-1 target) is highly expressed, leading to a decrease in phospholamban phosphorylation, sarco/endoplasmic reticulum Ca2+ -ATPase, and cAMP-responsive element binding activity. I-1 knockout mice lack phospholamban phosphorylation and exhibit vascular smooth muscle cell arrest in the synthetic state with excessive neointimal proliferation after carotid injury, as well as significant modifications of contractile properties and relaxant response to acetylcholine of femoral artery in vivo. Constitutively active I-1 gene transfer decreased neointimal formation in an angioplasty rat model by preventing vascular smooth muscle cell contractile to synthetic phenotype change. I-1 and sarco/endoplasmic reticulum Ca2+ -ATPase synergistically induce the vascular smooth muscle cell contractile phenotype. Gene transfer of constitutively active I-1 is a promising therapeutic strategy for preventing vascular proliferative disorders.

  8. [Mechanisms of smooth endoplasmic reticulum aggregates creation in oocyte's cytoplasm in IVF cycles and its clinical relevance (literature review)].

    PubMed

    Kovalskaya, E V; Makarova, N P; Syrkasheva, A G; Dolgushina, N V; Kurilo, L F

    2015-01-01

    A large proportion of human oocytes received from exogenous gonadotropin-stimulated cycles have different morphological attributes, or dysmorphisms. The presence of dysmorphism can affect the fertilization rate, the embryo quality and subsequently the frequency of occurrence of implantation and pregnancy. Special attention is paid to oocytes with cytoplasmic attributes such as alteration of cytoplasmic granularity, the appearance of vacuoles, lipofuscin bodies and visible (large) aggregates of smooth endoplasmic reticulum. Endoplasmic reticulum (ER) is a type of the organelle forming an interconnected network of flattened, membrane-enclosed sacs or tubes. One of the main functions of ER in the oocyte is storage and redistribution of calcium, which provides cell activation during fertilization. Furthermore, complex of ER and mitochondria is necessary for accumulation of energy, synthesis of lipids and triglycerides, as well as synthesis of cytosolic and nuclear membranes during the early stages of cleavage. The appearance of anomalously large aggregates of ER in oocytes correlates with a low fertilization rate, low embryo quality, and pregnancy rate. The aim of the manuscript is to summarize current understanding of the mechanism of formation of such pathology of oocytes, together with special aspects of their fertilization and embryo quality.

  9. Reversible interactions between smooth domains of the endoplasmic reticulum and mitochondria are regulated by physiological cytosolic Ca2+ levels.

    PubMed

    Goetz, Jacky G; Genty, Hélène; St-Pierre, Pascal; Dang, Thao; Joshi, Bharat; Sauvé, Rémy; Vogl, Wayne; Nabi, Ivan R

    2007-10-15

    The 3F3A monoclonal antibody to autocrine motility factor receptor (AMFR) labels mitochondria-associated smooth endoplasmic reticulum (ER) tubules. siRNA down-regulation of AMFR expression reduces mitochondria-associated 3F3A labelling. The 3F3A-labelled ER domain does not overlap with reticulon-labelled ER tubules, the nuclear membrane or perinuclear ER markers and only partially overlaps with the translocon component Sec61alpha. Upon overexpression of FLAG-tagged AMFR, 3F3A labelling is mitochondria associated, excluded from the perinuclear ER and co-distributes with reticulon. 3F3A labelling therefore defines a distinct mitochondria-associated ER domain. Elevation of free cytosolic Ca(2+) levels with ionomycin promotes dissociation of 3F3A-labelled tubules from mitochondria and, judged by electron microscopy, disrupts close contacts (<50 nm) between smooth ER tubules and mitochondria. The ER tubule-mitochondria association is similarly disrupted upon thapsigargin-induced release of ER Ca(2+) stores or purinergic receptor stimulation by ATP. The inositol (1,4,5)-trisphosphate [Ins(1,4,5)P(3)] receptor (IP3R) colocalises to 3F3A-labelled mitochondria-associated ER tubules, and conditions that induce ER tubule-mitochondria dissociation disrupt continuity between 3F3A- and IP3R-labelled ER domains. RAS-transformed NIH-3T3 cells have increased basal cytosolic Ca(2+) levels and show dissociation of the 3F3A-labelled, but not IP3R-labelled, ER from mitochondria. Our data indicate that regulation of the ER-mitochondria association by free cytosolic Ca(2+) is a characteristic of smooth ER domains and that multiple mechanisms regulate the interaction between these organelles.

  10. GLP-1 promotes mitochondrial metabolism in vascular smooth muscle cells by enhancing endoplasmic reticulum-mitochondria coupling.

    PubMed

    Morales, Pablo E; Torres, Gloria; Sotomayor-Flores, Cristian; Peña-Oyarzún, Daniel; Rivera-Mejías, Pablo; Paredes, Felipe; Chiong, Mario

    2014-03-28

    Incretin GLP-1 has important metabolic effects on several tissues, mainly through the regulation of glucose uptake and usage. One mechanism for increasing cell metabolism is modulating endoplasmic reticulum (ER)-mitochondria communication, as it allows for a more efficient transfer of Ca(2+) into the mitochondria, thereby increasing activity. Control of glucose metabolism is essential for proper vascular smooth muscle cell (VSMC) function. GLP-1 has been shown to produce varied metabolic actions, but whether it regulates glucose metabolism in VSMC remains unknown. In this report, we show that GLP-1 increases mitochondrial activity in the aortic cell line A7r5 by increasing ER-mitochondria coupling. GLP-1 increases intracellular glucose and diminishes glucose uptake without altering glycogen content. ATP, mitochondrial potential and oxygen consumption increase at 3h of GLP-1 treatment, paralleled by increased Ca(2+) transfer from the ER to the mitochondria. Furthermore, GLP-1 increases levels of Mitofusin-2 (Mfn2), an ER-mitochondria tethering protein, via a PKA-dependent mechanism. Accordingly, PKA inhibition and Mfn2 down-regulation prevented mitochondrial Ca(2+) increases in GLP-1 treated cells. Inhibiting both Ca(2+) release from the ER and Ca(2+) entry into mitochondria as well as diminishing Mfn2 levels blunted the increase in mitochondrial activity in response to GLP-1. Altogether, these results strongly suggest that GLP-1 increases ER-mitochondria communication in VSMC, resulting in higher mitochondrial activity. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Lipocalin-2 Promotes Endoplasmic Reticulum Stress and Proliferation by Augmenting Intracellular Iron in Human Pulmonary Arterial Smooth Muscle Cells

    PubMed Central

    Wang, Guoliang; Liu, Shenghua; Wang, Li; Meng, Liukun; Cui, Chuanjue; Zhang, Hao; Hu, Shengshou; Ma, Ning; Wei, Yingjie

    2017-01-01

    Endoplasmic reticulum (ER) stress, a feature of many conditions associated with pulmonary hypertension (PH), is increasingly recognized as a common response to promote proliferation in the walls of pulmonary arteries. Increased expression of Lipocalin-2 in PH led us to test the hypothesis that Lipocalin-2, a protein known to sequester iron and regulate it intracellularly, might facilitate the ER stress and proliferation in pulmonary arterial smooth muscle cells (PASMCs). In this study, we observed greatly increased Lcn2 expression accompanied with increased ATF6 cleavage in a standard rat model of pulmonary hypertension induced by monocrotaline. In cultured human PASMCs, Lcn2 significantly promoted ER stress (determined by augmented cleavage and nuclear localization of ATF6, up-regulated transcription of GRP78 and NOGO, increased expression of SOD2, and mild augmented mitochondrial membrane potential) and proliferation (assessed by Ki67 staining and BrdU incorporation). Lcn2 promoted ER stress accompanied with augmented intracellular iron levels in human PASMCs. Treatment human PASMCs with FeSO4 induced the similar ER stress and proliferation response and iron chelator (deferoxamine) abrogated the ER stress and proliferation induced by Lcn2 in cultured human PASMCs. In conclusion, Lcn2 significantly promoted human PASMC ER stress and proliferation by augmenting intracellular iron. The up-regulation of Lcn2 probably involved in the pathogenesis and progression of PH. PMID:28255266

  12. Embryological outcomes in cycles with human oocytes containing large tubular smooth endoplasmic reticulum clusters after conventional in vitro fertilization.

    PubMed

    Itoi, Fumiaki; Asano, Yukiko; Shimizu, Masashi; Honnma, Hiroyuki; Murata, Yasutaka

    2016-01-01

    There have been no studies analyzing the effect of large aggregates of tubular smooth endoplasmic reticulum (aSERT) after conventional in vitro fertilization (cIVF). The aim of this study was to investigate whether aSERT can be identified after cIVF and the association between the embryological outcomes of oocytes in cycles with aSERT. This is a retrospective study examining embryological data from cIVF cycles showing the presence of aSERT in oocytes 5-6 h after cIVF. To evaluate embryo quality, cIVF cycles with at least one aSERT-metaphase II (MII) oocyte observed (cycles with aSERT) were compared to cycles with normal-MII oocytes (control cycles). Among the 4098 MII oocytes observed in 579 cycles, aSERT was detected in 100 MII oocytes in 51 cycles (8.8%). The fertilization rate, the rate of embryo development on day 3 and day 5-6 did not significantly differ between cycles with aSERT and control group. However, aSERT-MII oocytes had lower rates for both blastocysts and good quality blastocysts (p < 0.05). aSERT can be detected in the cytoplasm by removing the cumulus cell 5 h after cIVF. However, aSERT-MII oocytes do not affect other normal-MII oocytes in cycles with aSERT.

  13. Lipocalin-2 Promotes Endoplasmic Reticulum Stress and Proliferation by Augmenting Intracellular Iron in Human Pulmonary Arterial Smooth Muscle Cells.

    PubMed

    Wang, Guoliang; Liu, Shenghua; Wang, Li; Meng, Liukun; Cui, Chuanjue; Zhang, Hao; Hu, Shengshou; Ma, Ning; Wei, Yingjie

    2017-01-01

    Endoplasmic reticulum (ER) stress, a feature of many conditions associated with pulmonary hypertension (PH), is increasingly recognized as a common response to promote proliferation in the walls of pulmonary arteries. Increased expression of Lipocalin-2 in PH led us to test the hypothesis that Lipocalin-2, a protein known to sequester iron and regulate it intracellularly, might facilitate the ER stress and proliferation in pulmonary arterial smooth muscle cells (PASMCs). In this study, we observed greatly increased Lcn2 expression accompanied with increased ATF6 cleavage in a standard rat model of pulmonary hypertension induced by monocrotaline. In cultured human PASMCs, Lcn2 significantly promoted ER stress (determined by augmented cleavage and nuclear localization of ATF6, up-regulated transcription of GRP78 and NOGO, increased expression of SOD2, and mild augmented mitochondrial membrane potential) and proliferation (assessed by Ki67 staining and BrdU incorporation). Lcn2 promoted ER stress accompanied with augmented intracellular iron levels in human PASMCs. Treatment human PASMCs with FeSO4 induced the similar ER stress and proliferation response and iron chelator (deferoxamine) abrogated the ER stress and proliferation induced by Lcn2 in cultured human PASMCs. In conclusion, Lcn2 significantly promoted human PASMC ER stress and proliferation by augmenting intracellular iron. The up-regulation of Lcn2 probably involved in the pathogenesis and progression of PH.

  14. Endoplasmic reticulum is a key organella in bradykinin-triggered ATP release from cultured smooth muscle cells.

    PubMed

    Zhao, Yumei; Migita, Keisuke; Sato, Chiemi; Usune, Sadaharu; Iwamoto, Takahiro; Katsuragi, Takeshi

    2007-09-01

    ATP has broad functions as an autocrine/paracrine molecule. The mode of ATP release and its intracellular source, however, are little understood. Here we show that bradykinin via B(2)-receptor stimulation induces the extracellular release of ATP via the inositol 1,4,5-trisphosphate [Ins(1,4,5)P(3)]-signaling pathway in cultured taenia coli smooth muscle cells. It was found that bradykinin also increased the production of Ins(1,4,5)P(3) and 2-APB-inhibitable [Ca(2+)](i). The evoked release of ATP was suppressed by the Ca(2+)-channel blockers, nifedipine, and verapamil. Moreover, the extracellular release of ATP was elicited by photoliberation of Ins(1,4,5)P(3). Bradykinin caused a quick and transient accumulation of intracellular ATP from cells treated with 1% perchloric acid solution (PCA), but not with the cell lysis buffer. Peak accumulation was prevented by 2-APB and thapsigargin, but not by nifedipine or verapamil, inhibitors of extracellular release of ATP. These findings suggest that bradykinin elicits the extracellular release of ATP that is mediated by the Ins(1,4,5)P(3)-induced Ca(2+) signaling and, finally, leads to a Ca(2+)-dependent export of ATP from the cells. Furthermore, the bradykinin-induced transient accumulation of ATP in the cells treated with PCA may imply a possible release of ATP from the endoplasmic reticulum.

  15. Differential modulation of immunostimulant-triggered NO production by endoplasmic reticulum stress inducers in vascular smooth muscle cells.

    PubMed

    Ohta, Satoshi; Hattori, Yoshiyuki; Nakanishi, Nobuo; Sugimoto, Hiroyuki; Kasai, Kikuo

    2011-04-01

    We investigated the effects of endoplasmic reticulum (ER) stress inducers thapsigargin (TG) and tunicamycin (Tm) on immunostimulant lipopolysaccharide/interferon (LPS/IFN)-induced expression of isoform of nitric oxide synthase (iNOS) and nitric oxide (NO) production in vascular smooth muscle cells. LPS/IFN-induced iNOS mRNA expression was markedly enhanced by TG, whereas iNOS mRNA expression was strongly attenuated by Tm. Similarly, production of iNOS protein was markedly upregulated by TG but virtually eliminated by Tm. LPS/IFN-induced guanosine triphosphate cyclohydrolase I mRNA expression was slightly reduced by TG and markedly inhibited by Tm. Similarly, LPS/IFN-mediated induction of cellular biopterin was modestly reduced by TG and markedly inhibited by Tm. TG modestly enhanced LPS/IFN-induced activation of NF-κB, whereas Tm had no effect on it. Cellular respiration was reduced by TG and Tm in a concentration-dependent manner, which was confirmed by apoptosis assay. Thus, TG and Tm-induced ER stress and differently modulated NO production through alterations in iNOS expression and activity independently of NF-κB activation and caused a similar degree of ER stress-induced apoptosis.

  16. Interferon-induced, antiviral human MxA protein localizes to a distinct subcompartment of the smooth endoplasmic reticulum.

    PubMed

    Stertz, Silke; Reichelt, Mike; Krijnse-Locker, Jacomine; Mackenzie, Jason; Simpson, Jeremy C; Haller, Otto; Kochs, Georg

    2006-09-01

    Human MxA protein belongs to the superfamily of dynamin-like large GTPases that are involved in intracellular membrane trafficking. MxA is induced by interferons-alpha/beta (IFN-alpha/beta) and is a key component of the antiviral response against RNA viruses. Here, we show that MxA localizes to membranes that are positive for specific markers of the smooth endoplasmic reticulum, such as Syntaxin17, but is excluded from other membrane compartments. Overexpression of MxA leads to a characteristic reorganization of the associated membranes. Interestingly, Hook3, mannose-6-phosphate receptor, and Lamp-1, which normally accumulate in cis- Golgi, endosomes, and lysosomes, respectively, also colocalized with MxA, indicating that these markers were redistributed to the MxA-positive compartment. Functional assays, however, did not show any effect of MxA on endocytosis or the secretory pathway. The present results demonstrate that MxA is an IFN-induced antiviral effector protein that resembles the constitutively expressed large GTPase family members in its capacity to localize to and reorganize intracellular membranes.

  17. Endoplasmic Reticulum Stress-Mediated Apoptosis Contributing to High Glucose-Induced Vascular Smooth Muscle Cell Calcification.

    PubMed

    Zhu, Qiang; Guo, Runmin; Liu, Chang; Fu, Duguan; Liu, Fuyuan; Hu, Jiefen; Jiang, Hong

    2015-01-01

    Vascular calcification (VC) is a common feature in patients with type 2 diabetes mellitus, a metabolic disorder that is characterized by hyperglycemia (high blood glucose) in the context of insulin resistance and a relative lack of insulin. Recently, a few studies have indicated that a high concentration of glucose amplifies the osteogenesis of vascular smooth muscle cells (VSMCs). Some previous reports state that endoplasmic reticulum (ER) stress-mediated apoptosis was activated in and contributed to VC. However, whether or not high glucose could induce ER stress-mediated apoptosis and then involve the pathogenesis of VC remains unclear. The purpose of the present study was to investigate whether high blood glucose-induced VC in diabetes mellitus is caused by the ER response and subsequent apoptosis. We examined the effects of high glucose on the ER stress response of VSMCs. High glucose treatment drastically increased the ER stress response in VSMCs. The high glucose-induced osteoblastic differentiation of VSMCs was significantly attenuated by pretreatment with 500 μM of 4-PBA (an ER stress inhibitor) prior to the exposure to high glucose, as evidenced by decreases in the expression of Runx2 and activity of alkaline phosphatase, as well as calcium nodules. These results suggest that high glucose induces the ER stress response and apoptosis, leading to high glucose-elicited VC. © 2016 S. Karger AG, Basel.

  18. Clinical outcomes after IVF or ICSI using human blastocysts derived from oocytes containing aggregates of smooth endoplasmic reticulum.

    PubMed

    Itoi, Fumiaki; Asano, Yukiko; Shimizu, Masashi; Nagai, Rika; Saitou, Kanako; Honnma, Hiroyuki; Murata, Yasutaka

    2017-01-25

    In this study the clinical and neo-natal outcomes after transfer of blastocysts derived from oocytes containing aggregates of smooth endoplasmic reticulum (SER) were compared between IVF and intracytoplasmic sperm injection (ICSI) cycles. Clinical and neo-natal outcomes of blastocysts in cycles with at least one SER metaphase II oocyte (SER + MII; SER + cycles) did not significantly differ between the two insemination methods. When SER + MII were cultured to day 5/6, fertilization, embryo cleavage and blastocyst rates were not significantly different between IVF and ICSI cycles. In vitrified-warmed blastocyst transfer cycles, the clinical pregnancy rates from SER + MII in IVF and ICSI did not significantly differ. In this study, 52 blastocysts (27 IVF and 25 ICSI) derived from SER + MII were transferred, yielding 15 newborns (5 IVF and 10 ICSI) and no malformations. Moreover, 300 blastocysts (175 IVF and 125 ICSI) derived from SER-MII were transferred, yielding 55 newborns (24 IVF and 31 ICSI cycles). Thus, blastocysts derived from SER + cycles exhibited an acceptable ongoing pregnancy rate after IVF (n = 125) or ICSI (n = 117) cycles. In conclusion, blastocysts from SER + MII in both IVF and ICSI cycles yield adequate ongoing pregnancy rates with neo-natal outcomes that do not differ from SER-MII.

  19. Acetylation in vitro of constituent polypeptides by smooth endoplasmic reticulum (SER) and Golgi membrane fractions

    SciTech Connect

    Sambasivam, H.; Murray, R.K.

    1986-05-01

    Many polypeptides of the membranes of the ER are phosphorylated. To determine if any such polypeptides are acetylated, microsomal and other classical subcellular fractions were incubated with (/sup 3/H) acetyl-CoA; the specific activity of the microsomal fraction (MF) was the greatest. SDS-PAGE revealed that some 20 polypeptides of the MF were acetylated; 2-D electrophoretograms extended this number to approximately 60. Separation of the MF into smooth (S) and rough (R) fractions showed that the great majority of the labelled polypeptides belonged to the former. Isolation of a Golgi fraction revealed that its acetylation activity was approximately 3-fold greater than the SER fraction. Extensive proteolytic digestion of the MF followed by radiochromatography disclosed some 9 components whose precise nature (acetylated amino acids and/or sialic acids, etc.) is under study. Assuming that the majority of the radioactivity is in the former components and that a similar process occurs in vivo, the authors suggest that the Golgi apparatus may be a major site of acetylation of membrane and possibly other proteins.

  20. Endoplasmic reticulum stress: an unrecognized actor in solid organ transplantation.

    PubMed

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

    2009-09-15

    Endoplasmic reticulum (ER) stress is an adaptive response to the accumulation of misfolded proteins within the ER, which can trigger cell dedifferentiation and cell suicide. Increasing evidences suggest its implication in mediating allograft injury. Herein, we summarize the mechanisms of ER stress and discuss its implication in allograft injury. Increasing our 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.

  1. Smooth endoplasmic reticulum dilation and degeneration in Purkinje neuron dendrites of aging ethanol-fed female rats.

    PubMed

    Dlugos, Cynthia A

    2006-01-01

    The effects of chronic ethanol consumption on the extensive Purkinje neuron (PN) dendritic arbor of male rats include dilation of the smooth endoplasmic reticulum (SER) and dendritic regression. The purpose of the present study was to examine the molecular layer of female rats for the presence of ethanol-related SER dilation and evidence of degeneration within the PN dendritic arbor. Twenty-one 12-month-old Fischer 344 female rats (n = 7/treatment group) received a liquid ethanol, liquid control, or rat chow diet for a period of 40 weeks. Ethanol-fed rats received 35% of their dietary calories as ethanol. Pair-fed rats received a liquid control diet that was isocaloric to the ethanol diet. Chow-fed rats received standard laboratory rat chow ad libitum. At the end of treatment, tissues from the anterior and posterior lobes of the cerebellar vermis were viewed and photographed with the electron microscope. The diameters of SER profiles were measured and the density of degenerating bodies within the PN dendritic arbor was quantitated. In the posterior lobe, ethanol-related SER dilation was apparent. In the anterior lobe, the density of degenerating bodies within PN dendritic shafts was significantly increased but SER dilation in PN dendritic shafts was absent. These results confirm that SER dilation and dendritic degeneration in PN dendrites may precede and contribute to ethanol-related regression in female rats. In addition, comparison of these results with data obtained in male rats from a previous study suggests that PN dendrites in females may be more sensitive to the effects of ethanol.

  2. Endoplasmic reticulum stress stimulates heme oxygenase-1 gene expression in vascular smooth muscle. Role in cell survival.

    PubMed

    Liu, Xiao-ming; Peyton, Kelly J; Ensenat, Diana; Wang, Hong; Schafer, Andrew I; Alam, Jawed; Durante, William

    2005-01-14

    Heme oxygenase-1 (HO-1) is a cytoprotective protein that catalyzes the degradation of heme to biliverdin, iron, and carbon monoxide (CO). In the present study, we found that endoplasmic reticulum (ER) stress induced by a variety of experimental agents stimulated a time- and concentration-dependent increase in HO-1 mRNA and protein in vascular smooth muscle cells (SMC). The induction of HO-1 by ER stress was blocked by actinomycin D or cycloheximide and was independent of any changes in HO-1 mRNA stability. Luciferase reporter assays indicated that ER stress stimulated HO-1 promoter activity via the antioxidant response element. Moreover, ER stress induced the nuclear import of Nrf2 and the binding of Nrf2 to the HO-1 antioxidant response element. Interestingly, ER stress stimulated SMC apoptosis, as demonstrated by annexin V binding, caspase-3 activation, and DNA laddering. The induction of apoptosis by ER stress was potentiated by HO inhibition, whereas it was prevented by addition of HO substrate. In addition, exposure of SMC to exogenously administered CO inhibited ER stress-mediated apoptosis, and this was associated with a decrease in the expression of the proapoptotic protein, GADD153. In contrast, the other HO-1 products failed to block apoptosis or GADD153 expression during ER stress. These results demonstrated that ER stress is an inducer of HO-1 gene expression in vascular SMC and that HO-1-derived CO acts in an autocrine fashion to inhibit SMC apoptosis. The capacity of ER stress to stimulate the HO-1/CO system provides a novel mechanism by which this organelle regulates cell survival.

  3. Subcellular calcium localization and AT0-dependent Ca2+-uptake by smooth endoplasmic reticulum in an invertebrate photoreceptor cell. An ultrastrucutral, cytochemical and X-ray microanalytical study.

    PubMed

    Walz, B

    1979-10-01

    In Hirudo medicinalis an extensive and highly elaborate three dimensional network of smooth endoplasmic reticulum cisternae is found in very close structural relationship to the receptive (microvillar) membrane, as reported for many other invertebrates. A variant of the potassium pyroantimonate technique showed that these submicrovillar endoplasmic reticulum cisternae (SMC) and mitochondria are major intracellular calcium stores. Furthermore, using saponine-skinned photoreceptors for an in situ accumulation experiment, calcium oxalate precipitates in SMC demonstrate that this organelle is able to accumulate Ca2+ from a concentration of 2 x 10(-5) M, when ATP, Mg2+, and oxalate ions are present in the accumulation medium. This result provides direct evidence for the hypothesis that SMC may play a particularly important role in the regulation of intracellular ionized calcium in invertebrate photoreceptor cells. Morphological evidence supports this view.

  4. Comparative toxicology of tetrachlorobiphenyls in mink and rats. I. Changes in hepatic enzyme activity and smooth endoplasmic reticulum volume

    SciTech Connect

    Gillette, D.M.; Corey, R.D.; Helferich, W.G.; McFarland, J.M.; Lowenstine, L.J.; Moody, D.E.; Hammock, B.D.; Shull, L.R.

    1987-01-01

    Mink have been shown previously to be extraordinarily sensitive to polychlorinated biphenyls (PCBs) and related classes of halogenated hydrocarbons. This study explored several aspects of the acute response of mink to two purified tetrachlorobiphenyl (TCB) congeners and compared their response with that of the rat, a less sensitive and more thoroughly studied species. Young female pastel mink and young female Sprague-Dawley rats received three daily intraperitoneal injections with equimolar doses of either 2,4,2',4'-TCB or 3,4,3',4'-TCB, and were sacrificed after 7 days. Two control groups were used for each species; one was allowed free access to food and the other was pair-fed to the 3,4,3',4'-TCB treatment group. Rats remained clinically normal, while mink treated with 3,4,3',4'-TCB developed severe anorexia, diarrhea, and melena. Both species had significant increases in hepatic cytochrome P-450 content and the characteristic shift in the spectral maxima from 450 to 448 nm in the 3,4,3',4'-TCB- but not in the 2,4,2',4'-TCB-treated animals. Rats but not mink had increased activities of several hepatic monooxygenases in response to both congeners while microsomal epoxide hydrolase was increased in rats after 2,4,2',4'-TCB and in mink after 3,4,3',4'-TCB. Significant increases in the relative volume of smooth endoplasmic reticulum within hepatocytes of 2,4,2',4'-TCB-treated rats but not mink were confirmed by ultrastructural morphometry. Accumulation of both congeners was greater in adipose tissue than in the liver of either species. In both species, concentrations in adipose tissue were much greater for 2,4,2',4'-TCB than for 3,4,3',4'-TCB. PCB toxicosis in mink, as in other species, appeared to be dependent on isomeric arrangement of chlorine substituents. However, unlike other species, the toxicosis was not associated with biochemical or morphological evidence of hepatic enzyme induction.

  5. Functional linkage of Na+-Ca2+-exchanger to sarco/endoplasmic reticulum Ca2+ pump in coronary artery: comparison of smooth muscle and endothelial cells.

    PubMed

    Davis, Kim A; Samson, Sue E; Hammel, Kaitlin E; Kiss, Lorand; Fulop, Ferenc; Grover, Ashok K

    2009-08-01

    An increase in cytosolic Ca(2+) concentration in coronary artery smooth muscle causes a contraction but in endothelium it causes relaxation. Na(+)-Ca(2+)-exchanger (NCX) may play a role in Ca(2+) dynamics in both the cell types. Here, the NCX-mediated (45)Ca(2+) uptake was compared in Na(+)-loaded pig coronary artery smooth muscle and endothelial cells. In both the cell types, this uptake was inhibited by KB-R7943, SEA 0400 and by monensin, but not by cariporide. Prior loading of the cells with the Ca(2+) chelator BAPTA increased the NCX-mediated (45)Ca(2+) uptake in smooth muscle but not in endothelial cells. In the presence or absence of BAPTA loading, the Na(+)-mediated (45)Ca(2+) uptake was greater in endothelial than in smooth muscle cells. In smooth muscle cells without BAPTA loading, thapsigargin diminished the NCX-mediated (45)Ca(2+) entry. This effect was not observed in endothelial cells or in either cell type after BAPTA loading. The results in the smooth muscle cells are consistent with a limited diffusional space model in which the NCX-mediated (45)Ca(2+) uptake was enhanced by chelation of cytosolic Ca(2+) or by its sequestration by the sarco/endoplasmic reticulum Ca(2+) pump (SERCA). They suggest a functional linkage between NCX and SERCA in the smooth muscle but not in the endothelial cells. The concept of a linkage between NCX and SERCA in smooth muscle was also confirmed by similar distribution of NCX and SERCA2 proteins when detergent-treated microsomes were fractionated by flotation on sucrose density gradients. Thus, the coronary artery smooth muscle and endothelial cells differ not only in the relative activities of NCX but also in its functional linkage to SERCA.

  6. Neuroeffector apparatus in gastrointestinal smooth muscle organs.

    PubMed

    Sanders, Kenton M; Hwang, Sung Jin; Ward, Sean M

    2010-12-01

    Control of gastrointestinal (GI) movements by enteric motoneurons is critical for orderly processing of food, absorption of nutrients and elimination of wastes. Work over the past several years has suggested that motor neurotransmission is more complicated than simple release of transmitter from nerve terminals and binding of receptors on smooth muscle cells. In fact the 'neuro-effector' junction in the tunica muscularis might consist of synaptic-like connectivity with specialized cells, and contributions from multiple cell types in integrated post-junctional responses. Interstitial cells of Cajal (ICC) were proposed as potential mediators in motor neurotransmission based on reduced post-junctional responses observed in W mutants that have reduced populations of ICC. More recent studies on W mutants have contradicted the original findings, and suggested that ICC may not be significant players in motor neurotransmission. This review examines the evidence for and against the role of ICC in motor neurotransmission and outlines areas for additional investigation that would help further resolve this controversy.

  7. Deliveries of normal healthy babies from embryos originating from oocytes showing the presence of smooth endoplasmic reticulum aggregates.

    PubMed

    Mateizel, I; Van Landuyt, L; Tournaye, H; Verheyen, G

    2013-08-01

    Should oocytes showing the presence of smooth endoplasmic reticulum aggregates (SER) be considered for embryo transfer? The present study shows that embryos derived from metaphase II oocyte with visible SER (SER+MII) have the capacity to develop normally and may lead to newborns with no major malformations. It has been reported that the presence of SER in the cytoplasm of oocytes has a negative impact on embryo development, and is associated with a decreased clinical outcome and an increased risk of congenital anomalies. Therefore, it has been recommended that embryos derived from SER-positive oocytes should not be transferred. Consecutive ICSI cycles with at least one SER+MII oocyte were retrospectively analyzed regarding embryological and pregnancy outcome and compared with ICSI cycles showing only oocytes without SER (SER-MII). In total, 394 SER-positive (SER+) cycles and 6845 SER-negative (SER-) cycles were analyzed. The Student's t-test, one-way analysis of variance test and χ(2) test were used for statistical analysis. P value of <0.05 was considered statistically significant. Comparable fertilization rates were observed in SER+ (76.2%) and SER- (73.5%) cycles. In case of blastocyst culture, the cycle efficiency was lower in SER+ than in SER- cycles (mean 42.2 versus 62.8%, P < 0.001). The pregnancy and clinical pregnancy (CP) rates per embryo transfer (ET) were comparable for SER+ and SER- cycles (37.6 versus 37.8% and 33.0 versus 32.4%, respectively). In the SER+ cycles, the fertilization rates of SER+MII and SER-MII (72.9 versus 77.0%), as well as the capacity to develop into good-quality embryos on Days 3 (62.3 versus 63.7%) and 5 (45.4 versus 47.4%), were similar. In the 364 SER+ cycles, the ETs were subdivided in: ET with only SER+MII (n = 31; 8.5%), ET with only SER-MII (n = 235; 64.5%) and ET with mixed SER+ and SER-MII (n = 98; 26.9%). The pregnancy (25.8, 37.4 and 41.8%, respectively) and CP rates (22.6, 32.4 and 37.9%, respectively) were not

  8. Hepatic glycogen synthesis in the fetal mouse: An ultrastructural, morphometric, and autoradiographic investigation of the relationship between the smooth endoplasmic reticulum and glycogen

    SciTech Connect

    Breslin, J.S.

    1989-01-01

    Fetal rodent hepatocytes undergo a rapid and significant accumulation of glycogen prior to birth. The distinct association of the smooth endoplasmic reticulum (SER) with glycogen during glycogen synthesis documented in the adult hepatocyte has not been clearly demonstrated in the fetus. The experiments described in this dissertation tested the hypothesis that SER is present and functions in the synthesis of fetal hepatic glycogen. Biochemical analysis, light microscopic (LM) histochemistry and electron microscope (EM) morphometry demonstrated that fetal hepatic glycogen synthesis began on day 15, with maximum accumulation occurring between days 17-19. Glycogen accumulation began in a small population of cells. Both the number of cells containing glycogen and the quantity of glycogen per cell increased as glycogen accumulated. Smooth endoplasmic reticulum (SER) was observed on day 14 of gestation and throughout fetal hepatic glycogen synthesis, primarily as dilated ribosome-free terminal extensions of rough endoplasmic reticulum (RER), frequently associated with glycogen. SER was in close proximity to isolated particles of glycogen and at the periphery of large compact glycogen deposits. Morphometry demonstrated that the membrane surface of SER in the average fetal hepatocyte increased as glycogen accumulated through day 18 and dropped significantly as glycogen levels peaked on day 19. Parallel alterations in RER membrane surface, indicated overall increases in ER membrane surface. Autoradiography following administration of {sup 3}H-galactose demonstrated that newly synthesized glycogen was deposited near profiles of SER at day 16 and at day 18; however, at day 18 the majority of label was uniformly distributed over glycogen remote from profiles of SER.

  9. Bladder smooth muscle organ culture preparation maintains the contractile phenotype

    PubMed Central

    Wang, Tanchun; Kendig, Derek M.; Chang, Shaohua; Trappanese, Danielle M.; Chacko, Samuel

    2012-01-01

    Smooth muscle cells, when subjected to culture, modulate from a contractile to a secretory phenotype. This has hampered the use of cell culture for molecular techniques to study the regulation of smooth muscle biology. The goal of this study was to develop a new organ culture model of bladder smooth muscle (BSM) that would maintain the contractile phenotype and aid in the study of BSM biology. Our results showed that strips of BSM subjected to up to 9 days of organ culture maintained their contractile phenotype, including the ability to achieve near-control levels of force with a temporal profile similar to that of noncultured tissues. The technical aspects of our organ culture preparation that were responsible, in part, for the maintenance of the contractile phenotype were a slight longitudinal stretch during culture and subjection of the strips to daily contraction-relaxation. The tissues contained viable cells throughout the cross section of the strips. There was an increase in extracellular collagenous matrix, resulting in a leftward shift in the passive length-tension relationship. There were no significant changes in the content of smooth muscle-specific α-actin, calponin, h-caldesmon, total myosin heavy chain, protein kinase G, Rho kinase-I, or the ratio of SM1 to SM2 myosin isoforms. Moreover the organ cultured tissues maintained functional voltage-gated calcium channels and large-conductance calcium-activated potassium channels. Therefore, we propose that this novel BSM organ culture model maintains the contractile phenotype and will be a valuable tool for the use in cellular/molecular biology studies of bladder myocytes. PMID:22896042

  10. An intimate liaison: spatial organization of the endoplasmic reticulum–mitochondria relationship

    PubMed Central

    de Brito, Olga Martins; Scorrano, Luca

    2010-01-01

    Organelle localization is often crucial to properly modulate cellular functions and signalling cascades. For example, the distribution of organelles in axons is crucial for their function and is dysregulated in several diseases. Similarly, relative positioning of two or more organelles is also important to perform certain specialized processes. Perhaps, the best-known form of interorganellar organization is that between endoplasmic reticulum (ER) and mitochondria. Close communication between these two compartments has been observed for a long time. Recent evidence suggests that this is the basis for a bidirectional communication regulating a number of physiological processes ranging from mitochondrial energy and lipid metabolism to Ca2+ signalling and cell death. The recent discovery of some of the molecular mediators of the tethering already allowed to extend the function of this paradigmatic spatial organization to previously unexpected functions, and will foster future research to explore it in cellular signalling cascades as well as in disease. PMID:20717141

  11. Aberrant Endoplasmic Reticulum Stress in Vascular Smooth Muscle Increases Vascular Contractility and Blood Pressure in Mice Deficient of AMP-Activated Protein Kinase-α2 In Vivo

    PubMed Central

    Liang, Bin; Wang, Shuangxi; Wang, Qilong; Zhang, Wencheng; Viollet, Benoit; Zhu, Yi; Zou, Ming-Hui

    2013-01-01

    Objective The endoplasmic reticulum (ER) plays a critical role in ensuring proper folding of newly synthesized proteins. Aberrant ER stress is reported to play a causal role in cardiovascular diseases. However, the effects of ER stress on vascular smooth muscle contractility and blood pressure remain unknown. The aim of this study was to investigate whether aberrant ER stress causes abnormal vasoconstriction and consequent high blood pressure in mice. Methods and Results ER stress markers, vascular smooth muscle contractility, and blood pressure were monitored in mice. Incubation of isolated aortic rings with tunicamycin or MG132, 2 structurally unrelated ER stress inducers, significantly increased both phenylephrine-induced vasoconstriction and the phosphorylation of myosin light chain (Thr18/Ser19), both of which were abrogated by pretreatment with chemical chaperones or 5-Aminoimidazole-4-carboxamide ribonucleotide and metformin, 2 potent activators for the AMP-activated protein kinase. Consistently, administration of tauroursodeoxycholic acid or 4-phenyl butyric acid, 2 structurally unrelated chemical chaperones, in AMP-activated protein kinase-α2 knockout mice lowered blood pressure and abolished abnormal vasoconstrictor response of AMP-activated protein kinase-α2 knockout mice to phenylephrine. Consistently, tunicamycin (0.01 μ/g per day) infusion markedly increased both systolic and diastolic blood pressure, both of which were ablated by coadministration of 4-phenyl butyric acid. Furthermore, 4-phenyl butyric acid or tauroursodeoxycholic acid, which suppressed angiotensin II infusion–induced ER stress markers in vivo, markedly lowered blood pressure in angiotensin II–infused mice in vivo. Conclusion We conclude that ER stress increases vascular smooth muscle contractility resulting in high blood pressure, and AMP-activated protein kinase activation mitigates high blood pressure through the suppression of ER stress in vivo. PMID:23288166

  12. Aberrant endoplasmic reticulum stress in vascular smooth muscle increases vascular contractility and blood pressure in mice deficient of AMP-activated protein kinase-α2 in vivo.

    PubMed

    Liang, Bin; Wang, Shuangxi; Wang, Qilong; Zhang, Wencheng; Viollet, Benoit; Zhu, Yi; Zou, Ming-Hui

    2013-03-01

    The endoplasmic reticulum (ER) plays a critical role in ensuring proper folding of newly synthesized proteins. Aberrant ER stress is reported to play a causal role in cardiovascular diseases. However, the effects of ER stress on vascular smooth muscle contractility and blood pressure remain unknown. The aim of this study was to investigate whether aberrant ER stress causes abnormal vasoconstriction and consequent high blood pressure in mice. ER stress markers, vascular smooth muscle contractility, and blood pressure were monitored in mice. Incubation of isolated aortic rings with tunicamycin or MG132, 2 structurally unrelated ER stress inducers, significantly increased both phenylephrine-induced vasoconstriction and the phosphorylation of myosin light chain (Thr18/Ser19), both of which were abrogated by pretreatment with chemical chaperones or 5-Aminoimidazole-4-carboxamide ribonucleotide and metformin, 2 potent activators for the AMP-activated protein kinase. Consistently, administration of tauroursodeoxycholic acid or 4-phenyl butyric acid, 2 structurally unrelated chemical chaperones, in AMP-activated protein kinase-α2 knockout mice lowered blood pressure and abolished abnormal vasoconstrictor response of AMP-activated protein kinase-α2 knockout mice to phenylephrine. Consistently, tunicamycin (0.01 μg/g per day) infusion markedly increased both systolic and diastolic blood pressure, both of which were ablated by coadministration of 4-phenyl butyric acid. Furthermore, 4-phenyl butyric acid or tauroursodeoxycholic acid, which suppressed angiotensin II infusion-induced ER stress markers in vivo, markedly lowered blood pressure in angiotensin II-infused mice in vivo. We conclude that ER stress increases vascular smooth muscle contractility resulting in high blood pressure, and AMP-activated protein kinase activation mitigates high blood pressure through the suppression of ER stress in vivo.

  13. Cytochrome P450 Organization and Function Are Modulated by Endoplasmic Reticulum Phospholipid Heterogeneity.

    PubMed

    Brignac-Huber, Lauren M; Park, Ji Won; Reed, James R; Backes, Wayne L

    2016-12-01

    Cytochrome P450s (P450s) comprise a superfamily of proteins that catalyze numerous monooxygenase reactions in animals, plants, and bacteria. In eukaryotic organisms, these proteins not only carry out reactions necessary for the metabolism of endogenous compounds, but they are also important in the oxidation of exogenous drugs and other foreign compounds. Eukaryotic P450 system proteins generally reside in membranes, primarily the endoplasmic reticulum or the mitochondrial membrane. These membranes provide a scaffold for the P450 system proteins that facilitate interactions with their redox partners as well as other P450s. This review focuses on the ability of specific lipid components to influence P450 activities, as well as the role of the membrane in P450 function. These studies have shown that P450s and NADPH-cytochrome P450 reductase appear to selectively associate with specific phospholipids and that these lipid-protein interactions influence P450 activities. Finally, because of the heterogeneous nature of the endoplasmic reticulum as well as other biologic membranes, the phospholipids are not arranged randomly but associate to generate lipid microdomains. Together, these characteristics can affect P450 function by 1) altering the conformation of the proteins, 2) influencing the P450 interactions with their redox partners, and 3) affecting the localization of the proteins into specific membrane microdomains. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

  14. Mechanisms of alcohol-induced endoplasmic reticulum stress and organ injuries.

    PubMed

    Ji, Cheng

    2012-01-01

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

  15. Ca2+-sequestering smooth endoplasmic reticulum in an invertebrate photoreceptor. I. Intracellular topography as revealed by OsFeCN staining and in situ Ca accumulation

    PubMed Central

    1982-01-01

    Two ultrastructural approaches were used in photoreceptor cells of the leech, Hirudo medicinalis, to (a) investigate the intracellular topography of the smooth endoplasmic reticulum (SER) and (b) identify among the various subregions of the SER those which might function as Ca-sequestering sites. When the cells are prefixed with CaCl2- containing glutaraldehyde and postfixed with osmium tetroxide- ferricyanide (OsFeCN), only a part of the total SER is specifically stained. The stained SER cisternae include the submicrovillar cisternae (SMC), subsurface cisternae (SSC), the nuclear envelope, Golgi- associated SER, paracrystalline SER, and SER associated with glycogen areas. An extensive tubular SER cisternal system always remains unstained. When the cells are permeabilized by saponin and subsequently incubated with Ca2+, MgATP, and oxalate, the SMC (Walz, 1979, Eur. J. Cell Biol. 20:83-91), the SSC and the nuclear envelope contain electron- opaque Ca-oxalate precipitates indicating their ability to function as an effective Ca2+ sink. The results show that the very elaborate SER in this photoreceptor cell includes many functionally heterogeneous subregions. Of special physiological significance are those components (SMC and SSC) which are effective in Ca2+-buffering in the immediate vicinity of the plasma membrane. PMID:6181073

  16. Mitofusin-2-mediated tethering of mitochondria and endoplasmic reticulum promotes cell cycle arrest of vascular smooth muscle cells in G0/G1 phase.

    PubMed

    Li, Dan; Li, Xiaolan; Guan, Yang; Guo, Xiaomei

    2015-06-01

    Mitofusin-2 (Mfn-2) is a hyperplasia suppressor. Changes in Mfn-2 expression are thought to reflect mitochondrial remodeling during cell proliferation. However, it is unclear how the participation of Mfn-2 in mitochondrial remodeling prevents cellular proliferation. Here we show that arresting vascular smooth muscle cells (VSMCs) in the G0/G1 phase by serum starvation up-regulates Mfn-2 expression and causes mitochondria to assemble into a tubular network and to attach to the endoplasmic reticulum (ER). In the S phase, short rod-shaped mitochondrial structures that were dissociated from the ER were observed. Levels of glucose, ATP, l-amino acid, and NADP(+) did not vary throughout the cell cycle. However, NAD(+) level was lower and NADH level was higher in the G0/G1 phase than in the S phase. Mitochondrial membrane potential was lower in the S phase than in the G0/G1 phase. Infecting VSMCs with an adenovirus encoding full-length Mfn-2 increased NADH level and reduced NAD(+) level, while infecting the cells with an adenovirus that silences the p21(ras) signature motif produced opposite effects. These results suggest that Mfn-2 up-regulation causes mitochondrial fusion into tubular networks and attachment to the ER, which in turn halts proliferation of VSMCs. © The Author 2015. Published by ABBS Editorial Office in association with Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences.

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

    PubMed

    Delmotte, Philippe; Sieck, Gary C

    2015-02-01

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

  18. Male Sprague-Dawley rats exposed to in utero di(n-butyl) phthalate: dose dependent and age-related morphological changes in Leydig cell smooth endoplasmic reticulum.

    PubMed

    Shirai, Masaru; Wakui, Shin; Wempe, Michael F; Mutou, Tomoko; Oyama, Noriko; Motohashi, Masaya; Takahashi, Hiroyuki; Kansaku, Norio; Asari, Masao; Hano, Hiroshi; Endou, Hitoshi

    2013-01-01

    When 100 mg/kg/day of di(n-butyl) phthalate (DBP) was intragastrically administered to pregnant Sprague-Dawley rats throughout gestation days 12 to 21, the male pups had similar body weights with no apparent physical differences (e.g., litter size, sex ratio) compared to that of the vehicle group. However, prominent age-related morphological alterations in the smooth endoplasmic reticulum (sER) of testicular Leydig cells (LCs) were observed once these animals reached puberty. At weeks 5 to 7, the abundant sER with non-dilated cisternae was distributed in LCs. Subsequently, although the number of LCs significantly increased, the amount of sER was significantly decreased at 9 to 14 weeks of age and had disappeared at 17 weeks. In contrast, the number of LCs and the amount of sER in LCs of the lower dose groups (10, 30, and 50 mg/kg/day) were similar to those of the vehicle group. Further, serum testosterone levels in the 100 mg/kg dose group were significantly lower during 5 to 17 weeks of age. While their luteinizing hormone (LH) level was significantly lower at 5 to 7 weeks of age, it became significantly higher during 9 to 17 weeks. The amount of sER in LCs decreased with age with the increase in LCs proliferation and serum LH levels in rat exposed in utero to DBP in a dose-dependent manner.

  19. The impact of Alpha/ESHRE consensus regarding oocytes with aggregates of smooth endoplasmic reticulum (SERa) on in vitro fertilization outcome.

    PubMed

    Restelli, Liliana; Delle Noci, Silvia; Mangiarini, Alice; Ferrari, Stefania; Somigliana, Edgardo; Paffoni, Alessio

    2015-11-01

    The present study aimed to gather information on the impact of Alpha/European Society of Human Reproduction and Embryology (ESHRE) consensus regarding oocytes with aggregates of smooth endoplasmic reticulum (SERa) on in vitro fertilization outcome. In particular, we investigated if patients undergoing intracytoplasmic sperm injection (ICSI) and whose oocytes are discarded due to SERa have a higher chance of embryo transfer cancellation compared to patients without SERa oocytes. This is a nested case-control study drawn from the cohort of women referring for in vitro fertilization with ICSI. Cases were patients showing at least one oocyte with SERa at the time of injection. Controls were subsequent patients showing no SERa oocytes and matched ratio 1:1 for age, clinical indication to in vitro fertilization (IVF), and body mass index. The main outcome was the rate of embryo transfer cancellation. The percentage of women experiencing a transfer cancellation (absence of suitable oocytes or viable embryos) in their ICSI cycle were significantly higher in cases (18 %) compared to controls (8 %) (p = 0.02); however, adjusted odds ratio for FSH and number of SERa oocytes, of follicles, of retrieved oocytes, and of inseminated oocytes were not statistically significant. We have shown that the exclusion of SERa oocytes from ICSI cycles causes an increased frequency of transfer cancellation. This effect is mostly due to the reduced number of available oocytes after exclusion of SERa oocytes.

  20. New endoplasmic reticulum stress regulator, Gipie, regulates the survival of vascular smooth muscle cells and the neointima formation after vascular injury.

    PubMed

    Noda, Tomonori; Maeda, Kengo; Hayano, Shinji; Asai, Naoya; Enomoto, Atsushi; Takahashi, Masahide; Murohara, Toyoaki

    2015-05-01

    The accumulation of unfolded protein in the endoplasmic reticulum (ER) initiates an adaptive stress response, termed the unfolded protein response. Previous studies suggested that ER stress might be involved in the formation of neointima after vascular injury. We recently discovered a novel regulator of ER stress, 78-kDa glucose-regulated protein-interacting protein induced by ER stress (Gipie). The objective of this study was to elucidate the role of Gipie using models of vascular disease. We investigated the functions of Gipie in cultured vascular smooth muscle cells (VSMCs) and in a vascular injury model of a rat carotid artery. The expression of Gipie was predominantly detected in synthetic VSMCs and to a much lesser extent in contractile VSMCs, which was augmented by treatment with thapsigargin. Gipie knockdown increased the phosphorylation levels of c-Jun N-terminal kinase and the number of apoptotic cells under ER stress. Moreover, Gipie knockdown decreased the mature form of collagen I in synthetic VSMCs. The expression of Gipie was rarely detected in the medial VSMCs of the intact carotid artery, whereas it was detected in most of the neointimal cells and some of the medial VSMCs after balloon injury. Depletion of Gipie in the rat carotid artery attenuated the neointimal thickening, which was accompanied by increased cell death in the neointima. Conversely, overexpression of Gipie augmented the neointimal thickening. Gipie participates in the ER stress response in VSMCs and plays an important role in neointima formation after vascular injury. © 2015 American Heart Association, Inc.

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

    PubMed Central

    Delmotte, Philippe; Sieck, Gary C.

    2015-01-01

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

  2. Proximity of Na+ -Ca2+ -exchanger and sarco/endoplasmic reticulum Ca2+ pump in pig coronary artery smooth muscle: fluorescence microscopy.

    PubMed

    Kuszczak, Iwona; Kuner, Rajneet; Samson, Sue E; Grover, Ashok K

    2010-06-01

    Pig coronary artery smooth muscle expresses the Na(+)-Ca(2+)-exchanger NCX1 and the sarco/endoplasmic reticulum (SER) Ca(2+) pump SERCA2. NCX has been proposed to play a role in refilling the SER Ca(2+) pool. Caveolae may also direct Ca(2+) traffic during cell signaling. Here, we use immunofluorescence microscopy to determine if there is proximity between NCX1, SERCA2, and the caveolar protein caveolin-1. Stacks of images of cell surface domains were analyzed. Image stacks for one protein were analyzed for overlap with another protein, with and without randomization or image shifting. Within the resolution of light microscopy, there is significant overlap in the distributions of NCX1, SERCA2, and caveolin-1 but the three proteins are not always co-localized. The proximity between NCX1, SERCA2 is consistent with the assertion that NCX may supply Ca(2+) for refilling the SER but this relationship is only partial. Similarly, caveolae may direct traffic in some Ca(2+) signaling pathways but not others.

  3. A model for the self-organization of exit sites in the endoplasmic reticulum.

    PubMed

    Heinzer, Stephan; Wörz, Stefan; Kalla, Claudia; Rohr, Karl; Weiss, Matthias

    2008-01-01

    Exit sites (ES) are specialized domains of the endoplasmic reticulum (ER) at which cargo proteins of the secretory pathway are packaged into COPII-coated vesicles. Although the essential COPII proteins (Sar1p, Sec23p-Sec24p, Sec13p-Sec31p) have been characterized in detail and their sequential binding kinetics at ER membranes have been quantified, the basic processes that govern the self-assembly and spatial organization of ERES have remained elusive. Here, we have formulated a generic computational model that describes the process of formation of ERES on a mesoscopic scale. The model predicts that ERES are arranged in a quasi-crystalline pattern, while their size strongly depends on the cargo-modulated kinetics of COPII turnover - that is, a lack of cargo leads to smaller and more mobile ERES. These predictions are in favorable agreement with experimental data obtained by fluorescence microscopy. The model further suggests that cooperative binding of COPII components, for example mediated by regulatory proteins, is a key factor for the experimentally observed organism-specific ERES pattern. Moreover, the anterograde secretory flux is predicted to grow when the average size of ERES is increased, whereas an increase in the number of (small) ERES only slightly alters the flux.

  4. Downregulation of the miR-30 family microRNAs contributes to endoplasmic reticulum stress in cardiac muscle and vascular smooth muscle cells.

    PubMed

    Chen, Ming; Ma, Guiling; Yue, Yin; Wei, Yu; Li, Qiang; Tong, Zichuan; Zhang, Lin; Miao, Guobin; Zhang, Jianjun

    2014-04-15

    Endoplasmic reticulum (ER) stress is a common subcellular response to stresses and central to ER stress is increased expression of glucose-regulated protein 78 (GRP78). However, the mechanisms for GRP78 upregulation remained poorly understood. Our study goal was to shed light on this issue. H2O2 was used to create cellular models of ER stress in neonatal rat ventricular cells (NRVCs) and rat aorta vascular smooth muscle cells (RAVSMCs). Molecular Biology techniques were used to quantify protein and mRNA levels. Luciferase reporter gene assay was employed to investigate miRNA targeting. MTT assay and ELISA were used to detect cell death. MiRNAs belonging to the miR-30 family including miR-30a, b, c, d and e were all downregulated in ER stress induced by H2O2 in cardiovascular cells NRVCs and RAVSMCs, along with the upregulation of GRP78, cleaved ATF6, CHOP, and cleaved caspase-12. GRP78 was confirmed to be a target gene for miR-30. Artificial knockdown of miR-30 by antimiR-30 triggered the phenotypic ER stress with significant GRP78/ATF6/CHOP/caspase-12 upregulations and cell death, while miR-30 replacement mitigated ER stress. Knockdown of CHOP by siRNA regulated all members of the miR-30 family whereas sequestration of C/EBP transcription factor by its decoy downregulated miR-30 miRNAs. Collectively, downregulation of the miR-30 family miRNAs contributes to the ER stress and the associated upregulation of GRP78 in the cardiovascular system. The participation of miR-30 creates a positive feedback loop in the ER stress signaling pathway. MiR-30 replacement may be a viable approach for alleviating disorders associated with ER stress. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  5. 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.

  6. iRAGE as a novel carboxymethylated peptide that prevents advanced glycation end product-induced apoptosis and endoplasmic reticulum stress in vascular smooth muscle cells.

    PubMed

    Maltais, Jean-Sébastien; Simard, Elie; Froehlich, Ulrike; Denault, Jean-Bernard; Gendron, Louis; Grandbois, Michel

    2016-02-01

    Advanced glycation end-products (AGE) and the receptor for AGE (RAGE) have been linked to numerous diabetic vascular complications. RAGE activation promotes a self-sustaining state of chronic inflammation and has been shown to induce apoptosis in various cell types. Although previous studies in vascular smooth muscle cells (VSMC) showed that RAGE activation increases vascular calcification and interferes with their contractile phenotype, little is known on the potential of RAGE to induce apoptosis in VSMC. Using a combination of apoptotic assays, we showed that RAGE stimulation with its ligand CML-HSA promotes apoptosis of VSMC. The formation of stress granules and the increase in the level of the associated protein HuR point toward RAGE-dependent endoplasmic reticulum (ER) stress, which is proposed as a key contributor of RAGE-induced apoptosis in VSMC as it has been shown to promote cell death via numerous mechanisms, including up-regulation of caspase-9. Chronic NF-κB activation and modulation of Bcl-2 homologs are also suspected to contribute to RAGE-dependent apoptosis in VSMC. With the goal of reducing RAGE signaling and its detrimental impact on VSMC, we designed a RAGE antagonist (iRAGE) derived from the primary amino acid sequence of HSA. The resulting CML peptide was selected for the high glycation frequency of the primary sequence in the native protein in vivo. Pretreatment with iRAGE blocked 69.6% of the increase in NF-κB signaling caused by RAGE activation with CML-HSA after 48h. Preincubation with iRAGE was successful in reducing RAGE-induced apoptosis, as seen through enhanced cell survival by SPR and reduced PARP cleavage. Activation of executioner caspases was 63.5% lower in cells treated with iRAGE before stimulation with CML-HSA. To our knowledge, iRAGE is the first antagonist shown to block AGE-RAGE interaction and we propose the molecule as an initial candidate for drug discovery. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Mitochondrial and endoplasmic reticulum dysfunction and related defense mechanisms in critical illness-induced multiple organ failure.

    PubMed

    Thiessen, Steven E; Van den Berghe, Greet; Vanhorebeek, Ilse

    2017-02-17

    Patients with critical illness-induced multiple organ failure suffer from a very high morbidity and mortality, despite major progress in intensive care. The pathogenesis of this condition is complex and incompletely understood. Inadequate tissue perfusion and an overwhelming inflammatory response with pronounced cellular damage have been suggested to play an important role, but interventions targeting these disturbances largely failed to improve patient outcome. Hence, new therapeutic perspectives are urgently needed. Cellular dysfunction, hallmarked by mitochondrial dysfunction and endoplasmic reticulum stress, is increasingly recognized as an important contributor to the development of organ failure in critical illness. Several cellular defense mechanisms are normally activated when the cell is in distress, but may fail or respond insufficiently to critical illness. This insight may open new therapeutic options by stimulating these cellular defense mechanisms. This review summarizes the current understanding of the role of mitochondrial dysfunction and endoplasmic reticulum stress in critical illness-induced multiple organ failure and gives an overview of the corresponding cellular defense mechanisms. Therapeutic perspectives based on these cellular defense mechanisms are discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Endoplasmic reticulum proteins quality control and the unfolded protein response: the regulative mechanism of organisms against stress injuries.

    PubMed

    Fu, Xi Ling; Gao, Dong Sheng

    2014-01-01

    The endoplasmic reticulum is the cellular compartment in which secretory proteins are synthesized and folded. Perturbations of endoplasmic reticulum homeostasis lead to the accumulation of unfolded proteins. The activation of the unfolded protein response during endoplasmic reticulum stress transmits information about the status of protein folding to the cytosol and nucleus. The unfolded protein response leads to the upregulation of genes encoding endoplasmic reticulum chaperones, attenuation of translation, and initiation of the endoplasmic reticulum quality control system to restore endoplasmic reticulum homeostasis. When the unfolded protein response is insufficient to rebuild the steady state in endoplasmic reticulum, the programmed cell death or apoptosis would be initiated, by triggering cell injuries, even to cell death through apoptosis signals. In this review, we briefly outline research on the chaperones and foldases conserved in eukaryotes and plants, and describe the general principles and mechanisms of the endoplasmic reticulum quality control and the unfolded protein response. We describe the current models for the molecular mechanism of the unfolded protein response in plants, and emphasize the role of inositol requiring enzyme-1-dependent network in the unfolded protein response. Finally, we give a general overview of the directions for future research on the unfolded protein response in plants and its role in the response to environmental stresses. © 2014 International Union of Biochemistry and Molecular Biology.

  9. Male rats exposed in utero to di(n-butyl) phthalate: Age-related changes in Leydig cell smooth endoplasmic reticulum and testicular testosterone-biosynthesis enzymes/proteins.

    PubMed

    Motohashi, Masaya; Wempe, Michael F; Mutou, Tomoko; Takahashi, Hiroyuki; Kansaku, Norio; Ikegami, Masahiro; Inomata, Tomo; Asari, Masao; Wakui, Shin

    2016-01-01

    This study investigated the age-related (i.e., weeks 5, 7, 9, 14 and 17) morphological changes of Leydig cell smooth endoplasmic reticulum (LCs-ER) and testicular testosterone biosynthesis/protein expression in rats in utero exposed to di(n-butyl) phthalate (DBP) (intragastrically; 100mg/kg/day) on days 12-21 post-conception. Ultrastructural observations revealed the LCs-ER of the DBP group were non-dilated until peri-puberty, and thereafter decreased and disappeared. RT-PCR and Western blotting analyses revealed that StAR and P450scc levels in the DBP group were significantly lower at 5 and 7 weeks compared with the vehicle group but became similar during weeks 9-17. Although 3β-HSD, P450c17, and 17β-HSD levels of mRNA and protein in the DBP group were similar to the vehicle control group at 5 and 7 weeks of age, they were significantly lower during weeks 9-17. In utero DBP exposure results in age-related LCs-ER changes corresponding to reduction of testicular testosterone biosynthesis enzymes/associated proteins. Copyright © 2016. Published by Elsevier Inc.

  10. Autonomic nerves terminating on smooth muscle cells of vessels in the pineal organ of various mammals.

    PubMed

    Frank, C L; Dávid, C; Czirok, S; Vincze, C; Manzano, M J; Vígh, B

    2003-01-01

    The significance of autonomic nerves reaching the pincal organ was already investigated in connection to the innervation of pinealocytes and mediating light information from the retina for periodic melatonin secretion. In earlier works we found that some autonomic nerve fibers are not secretomotor but terminate on arteriolar smooth muscle cells in the pineal organ of the mink (Mustela vison). Studying in serial sections the pineal organ of the mink and 15 other mammalian species in the present work, we investigated whether similar axons of vasomotor-type are generally present in the wall of pineal vessels, further, whether they reach the organ via the conarian nerves or via periarterial plexuses. In all species investigated, axons of perivasal nerve bundles were found to form terminal enlargements on the smooth muscle layer of pineal arterioles. The neuromuscular endings contain several synaptic and some granular vesicles. Axon terminals are also present around pineal veins. In serial sections, we found that the so-called conarian autonomic nerves reach the pineal organ alongside pineal veins draining into the great internal cerebral vein. Similar nerves present near arteries of the arachnoid enter the pineal meningeal capsule and septa by arterioles, both perivenous and periarterial nerves form terminals of vasomotor-type. The arteriomotor and venomotor regulation of the tone of the vessels of the pineal organ may serve the vascular support for circadian and circannual periodic changes in metabolic activity of the pineal tissue.

  11. Endoplasmic reticulum and oxidant stress mediate nuclear factor-κB activation in the subfornical organ during angiotensin II hypertension.

    PubMed

    Young, Colin N; Li, Anfei; Dong, Frederick N; Horwath, Julie A; Clark, Catharine G; Davisson, Robin L

    2015-05-15

    Endoplasmic reticulum (ER) stress and reactive oxygen species (ROS) generation in the brain circumventricular subfornical organ (SFO) mediate the central hypertensive actions of Angiotensin II (ANG II). However, the downstream signaling events remain unclear. Here we tested the hypothesis that angiotensin type 1a receptors (AT1aR), ER stress, and ROS induce activation of the transcription factor nuclear factor-κB (NF-κB) during ANG II-dependent hypertension. To spatiotemporally track NF-κB activity in the SFO throughout the development of ANG II-dependent hypertension, we used SFO-targeted adenoviral delivery and longitudinal bioluminescence imaging in mice. During low-dose infusion of ANG II, bioluminescence imaging revealed a prehypertensive surge in NF-κB activity in the SFO at a time point prior to a significant rise in arterial blood pressure. SFO-targeted ablation of AT1aR, inhibition of ER stress, or adenoviral scavenging of ROS in the SFO prevented the ANG II-induced increase in SFO NF-κB. These findings highlight the utility of bioluminescence imaging to longitudinally track transcription factor activation during the development of ANG II-dependent hypertension and reveal an AT1aR-, ER stress-, and ROS-dependent prehypertensive surge in NF-κB activity in the SFO. Furthermore, the increase in NF-κB activity before a rise in arterial blood pressure suggests a causal role for SFO NF-κB in the development of ANG II-dependent hypertension. Copyright © 2015 the American Physiological Society.

  12. Endoplasmic reticulum and oxidant stress mediate nuclear factor-κB activation in the subfornical organ during angiotensin II hypertension

    PubMed Central

    Young, Colin N.; Li, Anfei; Dong, Frederick N.; Horwath, Julie A.; Clark, Catharine G.

    2015-01-01

    Endoplasmic reticulum (ER) stress and reactive oxygen species (ROS) generation in the brain circumventricular subfornical organ (SFO) mediate the central hypertensive actions of Angiotensin II (ANG II). However, the downstream signaling events remain unclear. Here we tested the hypothesis that angiotensin type 1a receptors (AT1aR), ER stress, and ROS induce activation of the transcription factor nuclear factor-κB (NF-κB) during ANG II-dependent hypertension. To spatiotemporally track NF-κB activity in the SFO throughout the development of ANG II-dependent hypertension, we used SFO-targeted adenoviral delivery and longitudinal bioluminescence imaging in mice. During low-dose infusion of ANG II, bioluminescence imaging revealed a prehypertensive surge in NF-κB activity in the SFO at a time point prior to a significant rise in arterial blood pressure. SFO-targeted ablation of AT1aR, inhibition of ER stress, or adenoviral scavenging of ROS in the SFO prevented the ANG II-induced increase in SFO NF-κB. These findings highlight the utility of bioluminescence imaging to longitudinally track transcription factor activation during the development of ANG II-dependent hypertension and reveal an AT1aR-, ER stress-, and ROS-dependent prehypertensive surge in NF-κB activity in the SFO. Furthermore, the increase in NF-κB activity before a rise in arterial blood pressure suggests a causal role for SFO NF-κB in the development of ANG II-dependent hypertension. PMID:25980014

  13. 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.

  14. Ultra-Smooth, Fully Solution-Processed Large-Area Transparent Conducting Electrodes for Organic Devices.

    PubMed

    Jin, Won-Yong; Ginting, Riski Titian; Ko, Keum-Jin; Kang, Jae-Wook

    2016-11-03

    A novel approach for the fabrication of ultra-smooth and highly bendable substrates consisting of metal grid-conducting polymers that are fully embedded into transparent substrates (ME-TCEs) was successfully demonstrated. The fully printed ME-TCEs exhibited ultra-smooth surfaces (surface roughness ~1.0 nm), were highly transparent (~90% transmittance at a wavelength of 550 nm), highly conductive (sheet resistance ~4 Ω ◻(-1)), and relatively stable under ambient air (retaining ~96% initial resistance up to 30 days). The ME-TCE substrates were used to fabricate flexible organic solar cells and organic light-emitting diodes exhibiting devices efficiencies comparable to devices fabricated on ITO/glass substrates. Additionally, the flexibility of the organic devices did not degrade their performance even after being bent to a bending radius of ~1 mm. Our findings suggest that ME-TCEs are a promising alternative to indium tin oxide and show potential for application toward large-area optoelectronic devices via fully printing processes.

  15. Ultra-Smooth, Fully Solution-Processed Large-Area Transparent Conducting Electrodes for Organic Devices

    NASA Astrophysics Data System (ADS)

    Jin, Won-Yong; Ginting, Riski Titian; Ko, Keum-Jin; Kang, Jae-Wook

    2016-11-01

    A novel approach for the fabrication of ultra-smooth and highly bendable substrates consisting of metal grid-conducting polymers that are fully embedded into transparent substrates (ME-TCEs) was successfully demonstrated. The fully printed ME-TCEs exhibited ultra-smooth surfaces (surface roughness ~1.0 nm), were highly transparent (~90% transmittance at a wavelength of 550 nm), highly conductive (sheet resistance ~4 Ω ◻‑1), and relatively stable under ambient air (retaining ~96% initial resistance up to 30 days). The ME-TCE substrates were used to fabricate flexible organic solar cells and organic light-emitting diodes exhibiting devices efficiencies comparable to devices fabricated on ITO/glass substrates. Additionally, the flexibility of the organic devices did not degrade their performance even after being bent to a bending radius of ~1 mm. Our findings suggest that ME-TCEs are a promising alternative to indium tin oxide and show potential for application toward large-area optoelectronic devices via fully printing processes.

  16. Ultra-Smooth, Fully Solution-Processed Large-Area Transparent Conducting Electrodes for Organic Devices

    PubMed Central

    Jin, Won-Yong; Ginting, Riski Titian; Ko, Keum-Jin; Kang, Jae-Wook

    2016-01-01

    A novel approach for the fabrication of ultra-smooth and highly bendable substrates consisting of metal grid-conducting polymers that are fully embedded into transparent substrates (ME-TCEs) was successfully demonstrated. The fully printed ME-TCEs exhibited ultra-smooth surfaces (surface roughness ~1.0 nm), were highly transparent (~90% transmittance at a wavelength of 550 nm), highly conductive (sheet resistance ~4 Ω ◻−1), and relatively stable under ambient air (retaining ~96% initial resistance up to 30 days). The ME-TCE substrates were used to fabricate flexible organic solar cells and organic light-emitting diodes exhibiting devices efficiencies comparable to devices fabricated on ITO/glass substrates. Additionally, the flexibility of the organic devices did not degrade their performance even after being bent to a bending radius of ~1 mm. Our findings suggest that ME-TCEs are a promising alternative to indium tin oxide and show potential for application toward large-area optoelectronic devices via fully printing processes. PMID:27808221

  17. Remeshed smoothed particle hydrodynamics simulation of the mechanical behavior of human organs.

    PubMed

    Hieber, Simone E; Walther, Jens H; Koumoutsakos, Petros

    2004-01-01

    In computer aided surgery the accurate simulation of the mechanical behavior of human organs is essential for the development of surgical simulators. In this paper we introduce particle based simulations of two different human organ materials modeled as linear viscoelastic solids. The constitutive equations for the material behavior are discretized using a particle approach based on the Smoothed Particle Hydrodynamics (SPH) method while the body surface is tracked using level sets. A key aspect of this approach is its flexibility which allows the simulation of complex time varying topologies with large deformations. The accuracy of the original formulation is significantly enhanced by using a particle reinitialization technique resulting in remeshed Smoothed Particle Hydrodynamics (rSPH). The mechanical parameters of the systems used in the simulations are derived from experimental measurements on human cadaver organs. We compare the mechanical behavior of liver- and kidney-like materials based on the dynamic simulations of a tensile test case. Moreover, we present a particle based reconstruction of the liver topology and its strain distribution under a small local load. Finally, we demonstrate a unified formulation of fluid structure interaction based on particle methods.

  18. Dense-cored vesicles, smooth endoplasmic reticulum, and mitochondria are closely associated with non-specialized parts of plasma membrane of nerve terminals: implications for exocytosis and calcium buffering by intraterminal organelles.

    PubMed

    Lysakowski, A; Figueras, H; Price, S D; Peng, Y Y

    1999-01-18

    To determine whether there are anatomical correlates for intraterminal Ca2+ stores to regulate exocytosis of dense-cored vesicles (DCVs) and whether these stores can modulate exocytosis of synaptic vesicles, we studied the spatial distributions of DCVs, smooth endoplasmic reticulum (SER), and mitochondria in 19 serially reconstructed nerve terminals in bullfrog sympathetic ganglia. On average, each bouton had three active zones, 214 DCVs, 26 SER fragments (SERFs), and eight mitochondria. DCVs, SERFs and mitochondria were located, on average, 690, 624, and 526 nm, respectively, away from active zones. Virtually no DCVs were within "docking" (i.e., < or = 50 nm) distances of the active zones. Thus, it is unlikely that DCV exocytosis occurs at active zones via mechanisms similar to those for exocytosis of synaptic vesicles. Because there were virtually no SERFs or mitochondria within 50 nm of any active zone, Ca2+ modulation by these organelles is unlikely to affect ACh release evoked by a single action potential. In contrast, 30% of DCVs and 40% of SERFs were located within 50 nm of the nonspecialized regions of the plasma membrane. Because each bouton had at least one SERF within 50 nm of the plasma membrane and most of these SERFs had DCVs, but not mitochondria, near them, it is possible for Ca2+ release from the SER to provide the Ca2+ necessary for DCV exocytosis. The fact that 60% of the mitochondria had some part within 50 nm of the plasma membrane means that it is possible for mitochondrial Ca2+ buffering to affect DCV exocytosis.

  19. Selenium suppresses oxidative-stress-enhanced vascular smooth muscle cell calcification by inhibiting the activation of the PI3K/AKT and ERK signaling pathways and endoplasmic reticulum stress.

    PubMed

    Liu, Hongmei; Li, Xiaoming; Qin, Fei; Huang, Kaixun

    2014-03-01

    Vascular calcification is a prominent feature of many diseases, including atherosclerosis, and it has emerged as a powerful predictor of cardiovascular morbidity and mortality. A number of studies have examined the association between selenium and risk of cardiovascular diseases, but little is known about the role of selenium in vascular calcification. To determine the role of selenium in regulating vascular calcification, we assessed the effect of sodium selenite on oxidative-stress-enhanced vascular smooth muscle cell (VSMC) calcification and the underlying mechanism. Oxidative stress induced by xanthine/xanthine oxidase increased apoptosis, as determined by Hoechst 33342 staining and annexin V/propidium iodide staining, and it enhanced osteoblastic differentiation and calcification of VSMCs, on the basis of alkaline phosphatase activity, the expression of Runx2 and type I collagen, and calcium deposition. These effects of oxidative stress were significantly inhibited by selenite. The following processes may explain the inhibitory effects of selenite: (1) selenite significantly suppressed oxidative stress, as evidenced by the decrease of the oxidative status of the cell and lipid peroxidation levels, as well as by the increase of the total protein thiol content and the activity of the antioxidant selenoenzyme glutathione peroxidase; (2) selenite significantly attenuated oxidative-stress-induced activation of the phosphatidylinositol 3-kinase/AKT and extracellular-signal-regulated kinase signaling pathways, resulting in decreased osteoblastic differentiation of VSMCs; (3) selenite significantly inhibited oxidative-stress-activated endoplasmic reticulum stress, thereby leading to decreased apoptosis. Our results suggest a potential role of selenium in the prevention of vascular calcification, which may provide more mechanistic insights into the relationship between selenium and cardiovascular diseases.

  20. The effect of spatial smoothing on fMRI decoding of columnar-level organization with linear support vector machine

    PubMed Central

    Misaki, Masaya; Luh, Wen-Ming; Bandettini, Peter A.

    2012-01-01

    We examined how spatial smoothing affects the result of multivariate classification analysis using the linear support vector machine (SVM) for decoding columnar-level organization. It has been suggested that the effect of spatial smoothing on decoding performance is minor because smoothing operation is an invertible data transformation and such invertible transformation does not remove information in multivariate pattern. Our theoretical consideration, however, revealed that generalization score (performance for test samples unused during classifier training) was susceptible to non-uniform scaling of input data; SVM classifier became less sensitive to variability in shrunk dimension. This result indicates that spatial smoothing reduces sensitivity of SVM classifier to high spatial frequency pattern so that the effect of smoothing implies the amount of information distributed in spatial frequencies. We also examined the effect of smoothing in an fMRI experiment of decoding ocular dominance responses. The results of group statistic showed that large smoothing reduced decoding accuracies while the smoothing effect at individual subject were not the same for all subjects. These results suggest that spatial smoothing can have major effect on decoding performance and the informative pattern for columnar level decoding resides in higher frequencies on average across subjects while it may distribute multiple frequencies at individual subject level. PMID:23174092

  1. Smooth ZnO:Al-AgNWs Composite Electrode for Flexible Organic Light-Emitting Device

    NASA Astrophysics Data System (ADS)

    Wang, Hu; Li, Kun; Tao, Ye; Li, Jun; Li, Ye; Gao, Lan-Lan; Jin, Guang-Yong; Duan, Yu

    2017-01-01

    The high interest in organic light-emitting device (OLED) technology is largely due to their flexibility. Up to now, indium tin oxide (ITO) films have been widely used as transparent conductive electrodes (TCE) in organic opto-electronic devices. However, ITO films, typically deposited on glass are brittle and they make it difficult to produce flexible devices, restricting their use for flexible devices. In this study, we report on a nano-composite TCE, which is made of a silver nanowire (AgNW) network, combined with aluminum-doped zinc oxide (ZnO:Al, AZO) by atomic layer deposition. The AgNWs/AZO composite electrode on photopolymer substrate shows a low sheet resistance of only 8.6 Ω/sq and a high optical transmittance of about 83% at 550 nm. These values are even comparable to conventional ITO on glass. In addition, the electrodes also have a very smooth surface (0.31 nm root-mean-square roughness), which is flat enough to contact the OLED stack. Flexible OLED were built with AgNWs/AZO electrodes, which suggests that this approach can replace conventional ITO TCEs in organic electronic devices in the future.

  2. Smooth ZnO:Al-AgNWs Composite Electrode for Flexible Organic Light-Emitting Device.

    PubMed

    Wang, Hu; Li, Kun; Tao, Ye; Li, Jun; Li, Ye; Gao, Lan-Lan; Jin, Guang-Yong; Duan, Yu

    2017-12-01

    The high interest in organic light-emitting device (OLED) technology is largely due to their flexibility. Up to now, indium tin oxide (ITO) films have been widely used as transparent conductive electrodes (TCE) in organic opto-electronic devices. However, ITO films, typically deposited on glass are brittle and they make it difficult to produce flexible devices, restricting their use for flexible devices. In this study, we report on a nano-composite TCE, which is made of a silver nanowire (AgNW) network, combined with aluminum-doped zinc oxide (ZnO:Al, AZO) by atomic layer deposition. The AgNWs/AZO composite electrode on photopolymer substrate shows a low sheet resistance of only 8.6 Ω/sq and a high optical transmittance of about 83% at 550 nm. These values are even comparable to conventional ITO on glass. In addition, the electrodes also have a very smooth surface (0.31 nm root-mean-square roughness), which is flat enough to contact the OLED stack. Flexible OLED were built with AgNWs/AZO electrodes, which suggests that this approach can replace conventional ITO TCEs in organic electronic devices in the future.

  3. Rehabilitation of the cavernous smooth muscle in patients with organic erectile dysfunction.

    PubMed

    Salem, H; Mostafa, T

    2012-04-01

    This study aimed at assessing the effect of regular use of intracorporeal injection (ICI), sildenafil citrate and vacuum constriction device (VCD) on cavernous smooth muscle and erectile activity. One hundred and sixty-five patients with organic erectile dysfunction were investigated for 3 months. The patient and his partner were classified prospectively after proper counselling: group I (n = 56) received ICI twice per week; group II (n = 55) received sildenafil 100 mg twice per week; and group III (n = 54) used VCD twice per week. Duplex ultrasound was carried out before and after treatment, and then, the patients were followed up for a month to assess the resumption of unaided erection. The results showed that there was significant improvement in mean peak systolic velocity (PSV) and mean cavernosal artery diameter (CAD) at the end of the treatment in all groups, being higher in the ICI group than in the other two groups. Also, the percentage of patients who resumed unaided intercourse were higher in the ICI group compared with the other two groups (17.9%, 9.1% and 3.7% respectively). It is concluded that repeated regular use of ICI, sildenafil or VCD by patients with organic erectile dysfunction has a positive impact on their cavernous blood flow and erectile activity.

  4. Nucleolar organizing regions and alpha-smooth muscle actin expression in a case of ameloblastic carcinoma.

    PubMed

    Kamath, Kavitha P; Vidya, M; Shetty, Nandaprasad; Karkera, Bhavana V; Jogi, Hemanth

    2010-06-01

    Ameloblastic carcinoma is a rare lesion of odontogenic origin. It is defined as a malignant epithelial odontogenic tumor that histologically has retained the features of ameloblastic differentiation and also exhibits cytologic features of malignancy, like atypia and mitotic activity. Although this lesion represents a separate entity, differentiating it from ameloblastoma has been often challenging to pathologists. In this case study reporting a case of ameloblastic carcinoma, we have attempted to verify the previous findings on the use of Argyrophilic nucleolar organizing regions (AgNORs) and immunohistochemical staining for the alpha-smooth muscle actin (alpha-SMA) in differentiating ameloblastic carcinoma from ameloblastoma. It was observed that AgNORs was found to be almost twice in ameloblastic carcinoma as it was in ameloblastoma. A difference between the two lesions in the pattern of expression of alpha-SMA was also observed, with alpha-SMA being expressed in the odontogenic epithelium and the stroma of ameloblastic carcinoma whereas, in the case of ameloblastoma, it was found only in the stromal part. These findings suggest that AgNORs and alpha-SMA expression may be used as adjuncts to the routine histopathologic examination to differentiate ameloblastic carcinoma and ameloblastoma.

  5. Nucleolar Organizing Regions and α-Smooth Muscle Actin Expression in a Case of Ameloblastic Carcinoma

    PubMed Central

    Vidya, M.; Shetty, Nandaprasad; Karkera, Bhavana V.; Jogi, Hemanth

    2010-01-01

    Ameloblastic carcinoma is a rare lesion of odontogenic origin. It is defined as a malignant epithelial odontogenic tumor that histologically has retained the features of ameloblastic differentiation and also exhibits cytologic features of malignancy, like atypia and mitotic activity. Although this lesion represents a separate entity, differentiating it from ameloblastoma has been often challenging to pathologists. In this case study reporting a case of ameloblastic carcinoma, we have attempted to verify the previous findings on the use of Argyrophilic nucleolar organizing regions (AgNORs) and immunohistochemical staining for the alpha-smooth muscle actin (alpha-SMA) in differentiating ameloblastic carcinoma from ameloblastoma. It was observed that AgNORs was found to be almost twice in ameloblastic carcinoma as it was in ameloblastoma. A difference between the two lesions in the pattern of expression of alpha-SMA was also observed, with alpha-SMA being expressed in the odontogenic epithelium and the stroma of ameloblastic carcinoma whereas, in the case of ameloblastoma, it was found only in the stromal part. These findings suggest that AgNORs and alpha-SMA expression may be used as adjuncts to the routine histopathologic examination to differentiate ameloblastic carcinoma and ameloblastoma. PMID:20333560

  6. Monocytes, endoplasmic reticulum stress and metabolomics in dogs with multiple organ dysfunction syndrome treated by continuous venovenous hemodiafiltration

    PubMed Central

    Xu, Yun-Peng; Sui, Xiao-Lu; Zhang, Ai-Sha; Ye, Lei; Gu, Feng-Juan; Chen, Ji-Hong

    2017-01-01

    Objectives We tried to investigate the mechanism of continuous venovenous hemodiafiltration (CVVHDF) treatment in monocytes function, endoplasmic reticulum (ER) stress signaling pathways, metabolomics and histopathological changes of MODS dogs, and aimed to enhance the understanding of pathogenesis and provide novel avenues to potential therapies. Methods 12 male Beagle dogs were used to develop the stable models of MODS by using hemorrhagic shock plus resuscitation and endotoxemia, and assigned randomly to CVVHDF group (n=6) and MODS group (n=6). The dogs in CVVHDF group were given the typical CVVHDF treatment for 24h after the completion of endotoxin intravenous infusion, while those in MODS group were offered the i.v heparin instead only. Serum sample were collected at five time points, i.e. before anesthesia, 0h, 6h, 12h and 24h after the endotoxin injection (T1˜T5, respectively), and meanwhile, the changes of mRNA, protein and human umbilical vein endothelial cells (HUVECs) apoptosis rates in JNK, CHOP and Caspase-12 were observed before and after interfered by RNA interference technology. Results The levels of DLA-DR, IL-1β and IL-4 were higher than those in MODS group after the CVVHDF treatment, and the early and late apoptosis rates showed downward trend compared with MODS group. In vitro and prior to RNA interference (RNAi), the levels of mRNA and protein expression and HUVECs apoptosis rates of JNK, CHOP and Caspase-12 in CVVHDF group were significantly lower compared to T1 and MODS group respectively. However, the levels of mRNA and protein expression and HUVECs apoptosis rates were significantly lower than those before interfered by RNAi in both two groups. The serum levels of LPCs, ornithine, proline, methionine, etc. were down-regulated while carnitines, FFAs, PC, etc. were increased significantly in MODS (T4), and the serum levels of methionine, proline, arginine and lysine were increased while carnitine, LPCs, PCs, SMs and orthophosporic acid were

  7. Smooth muscle myosin light chain kinase, supramolecular organization, modulation of activity, and related conformational changes.

    PubMed Central

    Filenko, A M; Danilova, V M; Sobieszek, A

    1997-01-01

    It has recently been suggested that activation of smooth muscle myosin light chain kinase (MLCK) can be modulated by formation of supramolecular structures (Sobieszek, A. 1991. Regulation of smooth muscle myosin light chain kinase. Allosteric effects and co-operative activation by CaM. J. Mol. Biol. 220:947-957). The present light scattering data demonstrate that the inactive (calmodulin-free) MLCK apoenzyme exists in solution as a mixture of oligomeric (2% by weight), dimeric (53%), and monomeric (45%) species at physiological ionic strength (160 mM salt). These long-living assemblies, the lifetime of which was measured by minutes, were in equilibrium with each other. The most likely form of the oligomer was a spiral-like hexamer, the dimensions of which fit very well the helical structure of self-assembled myosin filaments (Sobieszek, A. 1972. Cross-bridges on self-assembled smooth muscle myosin filaments. J. Mol. Biol. 70:741-744). After activation of the kinase by calmodulin (CaM) we could not detect any appreciable changes in the distribution of the kinase species either when the kinase was saturated with CaM or when its molar concentration exceeded that of CaM. Our fluorescent measurements suggest that the earlier observed inhibition of kinase at substoichiometric amounts of CaM (Sobieszek, A., A. Strobl, B. Ortner, and E. Babiychuk. 1993. Ca2+-calmodulin-dependent modification of smooth-muscle myosin light chain kinase leading to its co-operative activation by calmodulin. Biochem. J. 295:405-411) is associated with slow conformational change(s) of the activated (CaM-bound) kinase molecules. Such conformational rearrangements also took place with equimolar kinase to CaM; however, in this case there was no decrease in MLCK activity. The nature of these conformational changes, which are accompanied by reduction of the kinase for CaM affinity, is discussed. PMID:9284326

  8. STUDIES ON THE ENDOPLASMIC RETICULUM

    PubMed Central

    Porter, Keith R.; Yamada, Eichi

    1960-01-01

    Pigment epithelial cells of the frog's retina have been examined by methods of electron microscopy with special attention focused on the fine structure of the endoplasmic reticulum and the myeloid bodies. These cells, as reported previously, send apical prolongations into the spaces between the rod outer segments, and within these extensions, pigment migrates in response to light stimulation. The cytoplasm of these cells is filled with a compact lattice of membrane-limited tubules, the surfaces of which are smooth or particle-free. In this respect, the endoplasmic reticulum here resembles that encountered in cells which produce lipid-rich secretions. The myeloid bodies comprise paired membranes arranged in stacks shaped like biconvex lenses. At their margins the membranes are continuous with elements of the ER and in consequence of this the myeloid body is referred to as a differentiation of the reticulum. The paired membranes resemble in their thickness and spacings those which make up the outer segments; they are therefore regarded as intracellular photoreceptors of possible significance in the activation of pigment migration and other physiologic functions of these cells. The fuscin granules are enclosed in membranes which are also continuous with those of the ER. The granules seem to move independently of the prolongations in which they are contained. The report also describes the fine structure of the terminal bar apparatus, the fibrous layer intervening between the epithelium and the choroid blood vessels, and comments on the functions of the organelles depicted. PMID:13737277

  9. Periodic organization of the contractile apparatus in smooth muscle revealed by the motion of dense bodies in single cells

    PubMed Central

    1989-01-01

    To study the organization of the contractile apparatus in smooth muscle and its behavior during shortening, the movement of dense bodies in contracting saponin skinned, isolated cells was analyzed from digital images collected at fixed time intervals. These cells were optically lucent so that punctate structures, identified immunocytochemically as dense bodies, were visible in them with the phase contrast microscope. Methods were adapted and developed to track the bodies and to study their relative motion. Analysis of their tracks or trajectories indicated that the bodies did not move passively as cells shortened and that nearby bodies often had similar patterns of motion. Analysis of the relative motion of the bodies indicated that some bodies were structurally linked to one another or constrained so that the distance between them remained relatively constant during contraction. Such bodies tended to fall into laterally oriented, semirigid groups found at approximately 6-microns intervals along the cell axis. Other dense bodies moved rapidly toward one another axially during contraction. Such bodies were often members of separate semirigid groups. This suggests that the semirigid groups of dense bodies in smooth muscle cells may provide a framework for the attachment of the contractile structures to the cytoskeleton and the cell surface and indicates that smooth muscle may be more well-ordered than previously thought. The methods described here for the analysis of the motion of intracellular structures should be directly applicable to the study of motion in other cell types. PMID:2494193

  10. Vagal intramuscular array afferents form complexes with interstitial cells of Cajal in gastrointestinal smooth muscle: Analogues of muscle spindle organs?

    PubMed Central

    Powley, Terry L.; Phillips, Robert J.

    2011-01-01

    Intramuscular arrays (IMAs), vagal mechanoreceptors that innervate gastrointestinal smooth muscle, have not been completely described structurally or functionally. To delineate more fully the architecture of IMAs and to consider the structure-function implications of the observations, the present experiment examined the organization of the IMA terminal arbors and the accessory tissue elements of those arbors. IMA terminal fields, labeled by injection of biotinylated dextran into the nodose ganglia, were examined in whole mounts of rat gastric smooth muscle double-labeled with immunohistochemistry for interstitial cells of Cajal (ICCs; c-Kit) and/or inputs of different neuronal efferent transmitter (markers: TH, VChAT, and NOS) or afferent neuropeptidergic (CGRP) phenotypes. IMAs make extensive varicose and lamellar contacts with ICCs. In addition, axons of the multiple efferent and afferent phenotypes examined converge and articulate with IMA terminal arbors innervating ICCs. This architecture is consistent with the hypothesis that IMAs, or the multiply innervated IMA-ICC complexes they form, can function as stretch receptors. The tissue organization is also consonant with the proposal that those units can operate as functional analogues of muscle spindle organs. For electrophysiological assessments of IMA functions, experiments will need protocols that preserve both the complex architecture and the dynamic operations of IMA-ICC complexes. PMID:21530617

  11. Vagal intramuscular array afferents form complexes with interstitial cells of Cajal in gastrointestinal smooth muscle: analogues of muscle spindle organs?

    PubMed

    Powley, T L; Phillips, R J

    2011-07-14

    Intramuscular arrays (IMAs), vagal mechanoreceptors that innervate gastrointestinal smooth muscle, have not been completely described structurally or functionally. To delineate more fully the architecture of IMAs and to consider the structure-function implications of the observations, the present experiment examined the organization of the IMA terminal arbors and the accessory tissue elements of those arbors. IMA terminal fields, labeled by injection of biotinylated dextran into the nodose ganglia, were examined in whole mounts of rat gastric smooth muscle double-labeled with immunohistochemistry for interstitial cells of Cajal (ICCs; c-Kit) and/or inputs of different neuronal efferent transmitter (markers: tyrosine hydroxylase (TH), vesicular acetylcholine transporter (VAChT), and nitric oxide synthase (NOS)) or afferent neuropeptidergic (calcitonin gene-related peptide (CGRP)) phenotypes. IMAs make extensive varicose and lamellar contacts with ICCs. In addition, axons of the multiple efferent and afferent phenotypes examined converge and articulate with IMA terminal arbors innervating ICCs. This architecture is consistent with the hypothesis that IMAs, or the multiply innervated IMA-ICC complexes they form, can function as stretch receptors. The tissue organization is also consonant with the proposal that those units can operate as functional analogues of muscle spindle organs. For electrophysiological assessments of IMA functions, experiments will need protocols that preserve both the complex architecture and the dynamic operations of IMA-ICC complexes.

  12. Obesity-induced hepatic steatosis is mediated by endoplasmic reticulum stress in the subfornical organ of the brain

    PubMed Central

    Horwath, Julie A.; Hurr, Chansol; Butler, Scott D.; Guruju, Mallikarjun; Cassell, Martin D.; Mark, Allyn L.; Davisson, Robin L.; Young, Colin N.

    2017-01-01

    Nonalcoholic fatty liver disease (NAFLD), characterized by an excess accumulation of hepatic triglycerides, is a growing health epidemic. While ER stress in the liver has been implicated in the development of NAFLD, the role of brain ER stress — which is emerging as a key contributor to a number of chronic diseases including obesity — in NAFLD remains unclear. These studies reveal that chemical induction of ER stress in the brain caused hepatomegaly and hepatic steatosis in mice. Conversely, pharmacological reductions in brain ER stress in diet-induced obese mice rescued NAFLD independent of body weight, food intake, and adiposity. Evaluation of brain regions involved revealed robust activation of ER stress biomarkers and ER ultrastructural abnormalities in the circumventricular subfornical organ (SFO), a nucleus situated outside of the blood-brain-barrier, in response to high-fat diet. Targeted reductions in SFO-ER stress in obese mice via SFO-specific supplementation of the ER chaperone 78-kDa glucose–regulated protein ameliorated hepatomegaly and hepatic steatosis without altering body weight, food intake, adiposity, or obesity-induced hypertension. Overall, these findings indicate a novel role for brain ER stress, notably within the SFO, in the pathogenesis of NAFLD. PMID:28422749

  13. Ultra-thin and smooth transparent electrode for flexible and leakage-free organic light-emitting diodes

    PubMed Central

    Ok, Ki-Hun; Kim, Jiwan; Park, So-Ra; Kim, Youngmin; Lee, Chan-Jae; Hong, Sung-Jei; Kwak, Min-Gi; Kim, Namsu; Han, Chul Jong; Kim, Jong-Woong

    2015-01-01

    A smooth, ultra-flexible, and transparent electrode was developed from silver nanowires (AgNWs) embedded in a colorless polyimide (cPI) by utilizing an inverted film-processing method. The resulting AgNW-cPI composite electrode had a transparency of >80%, a low sheet resistance of 8 Ω/□, and ultra-smooth surfaces comparable to glass. Leveraging the robust mechanical properties and flexibility of cPI, the thickness of the composite film was reduced to less than 10 μm, which is conducive to extreme flexibility. This film exhibited mechanical durability, for both outward and inward bending tests, up to a bending radius of 30 μm, while maintaining its electrical performance under cyclic bending (bending radius: 500 μm) for 100,000 iterations. Phosphorescent, blue organic light-emitting diodes (OLEDs) were fabricated using these composites as bottom electrodes (anodes). Hole-injection was poor, because AgNWs were largely buried beneath the composite's surface. Thus, we used a simple plasma treatment to remove the thin cPI layer overlaying the nanowires without introducing other conductive materials. As a result, we were able to finely control the flexible OLEDs' electroluminescent properties using the enlarged conductive pathways. The fabricated flexible devices showed only slight performance reductions of <3% even after repeated foldings with a 30 μm bending radius. PMID:25824143

  14. CADASIL mutations and shRNA silencing of NOTCH3 affect actin organization in cultured vascular smooth muscle cells.

    PubMed

    Tikka, Saara; Ng, Yan Peng; Di Maio, Giuseppe; Mykkänen, Kati; Siitonen, Maija; Lepikhova, Tatiana; Pöyhönen, Minna; Viitanen, Matti; Virtanen, Ismo; Kalimo, Hannu; Baumann, Marc

    2012-12-01

    Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common hereditary vascular dementia caused by mutations in NOTCH3 gene. Pathology is manifested in small- and middle-sized arteries throughout the body, though primarily in cerebral white matter. Hemodynamics is altered in CADASIL and NOTCH3 is suggested to regulate actin filament polymerization and thereby vascular tone. We analyzed NOTCH3 expression and morphology of actin cytoskeleton in genetically genuine cultured human CADASIL vascular smooth muscle cells (VSMCs) (including a cell line homozygous for p.Arg133Cys mutation) derived from different organs, and in control VSMCs with short hairpin RNA (shRNA)-silenced NOTCH3. NOTCH3 protein level was higher in VSMCs derived from adult than newborn arteries in both CADASIL and control VSMCs. CADASIL VSMCs showed altered actin cytoskeleton including increased branching and node formation, and more numerous and smaller adhesion sites than control VSMCs. Alterations in actin cytoskeleton in shRNA-silenced VSMCs were similar as in CADASIL VSMCs. Severity of the alterations in actin filaments corresponded to NOTCH3 expression level being most severe in VSMCs derived from adult cerebral arteries. These observations suggest that hypomorphic NOTCH3 activity causes alterations in actin organization in CADASIL. Furthermore, arteries from different organs have specific characteristics, which modify the effects of the NOTCH3 mutation and which is one explanation for the exceptional susceptibility of cerebral white matter arteries.

  15. Artery Tertiary Lymphoid Organs Control Aorta Immunity and Protect against Atherosclerosis via Vascular Smooth Muscle Cell Lymphotoxin β Receptors

    PubMed Central

    Hu, Desheng; Mohanta, Sarajo K.; Yin, Changjun; Peng, Li; Ma, Zhe; Srikakulapu, Prasad; Grassia, Gianluca; MacRitchie, Neil; Dever, Gary; Gordon, Peter; Burton, Francis L.; Ialenti, Armando; Sabir, Suleman R.; McInnes, Iain B.; Brewer, James M.; Garside, Paul; Weber, Christian; Lehmann, Thomas; Teupser, Daniel; Habenicht, Livia; Beer, Michael; Grabner, Rolf; Maffia, Pasquale; Weih, Falk; Habenicht, Andreas J.R.

    2015-01-01

    Summary Tertiary lymphoid organs (TLOs) emerge during nonresolving peripheral inflammation, but their impact on disease progression remains unknown. We have found in aged Apoe−/− mice that artery TLOs (ATLOs) controlled highly territorialized aorta T cell responses. ATLOs promoted T cell recruitment, primed CD4+ T cells, generated CD4+, CD8+, T regulatory (Treg) effector and central memory cells, converted naive CD4+ T cells into induced Treg cells, and presented antigen by an unusual set of dendritic cells and B cells. Meanwhile, vascular smooth muscle cell lymphotoxin β receptors (VSMC-LTβRs) protected against atherosclerosis by maintaining structure, cellularity, and size of ATLOs though VSMC-LTβRs did not affect secondary lymphoid organs: Atherosclerosis was markedly exacerbated in Apoe−/−Ltbr−/− and to a similar extent in aged Apoe−/−Ltbrfl/flTagln-cre mice. These data support the conclusion that the immune system employs ATLOs to organize aorta T cell homeostasis during aging and that VSMC-LTβRs participate in atherosclerosis protection via ATLOs. PMID:26084025

  16. 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

  17. Nox NADPH oxidases and the endoplasmic reticulum.

    PubMed

    Laurindo, Francisco R M; Araujo, Thaís L S; Abrahão, Thalita B

    2014-06-10

    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. 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. 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. 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 Noxes and the ER may provide relevant insights in Nox-related (patho)physiology.

  18. Three-dimensional organization of the endoplasmic reticulum membrane around the mitochondrial constriction site in mammalian cells revealed by using focused-ion beam tomography.

    PubMed

    Ohta, Keisuke; Okayama, Satoko; Togo, Akinobu; Nakamura, Kei-Ichiro

    2014-11-01

    The endoplasmic reticulum (ER) and mitochondria associate at multiple contact sites to form specific domains known as mitochondria-ER associated membranes (MAMs) that play a role in the regulation of various cellular processes such as Ca2+ transfer, autophagy, and inflammation. Recently, it has been suggested that MAMs are also involved in mitochondrial dynamics, especially fission events. Cytological analysis showed that ER tubules were frequently located close to each other in mitochondrial fission sites that accumulate fission-related proteins. Three-dimensional (3D) imaging of ER-mitochondrial contacts in yeast mitochondria by using cryo-electron tomography also showed that ER tubules were attached near the constriction site, which is considered to be a fission site1). MAMs have been suggested to play a role in the initiation of mitochondrial fission, although the molecular relationships between MAMs and the mitochondrial fission process have not been established. Although an ER-mitochondrial membrane association has also been observed at the fission site in mammalian mitochondria, the detailed organization of MAMs around mammalian mitochondria remains to be established. To visualize the 3D distribution of the ER-mitochondrial contacts around the mitochondria, especially around the constriction site in mammalian cells, we attempted 3D structural analysis of the mammalian cytoplasm using high-resolution focused ion-beam scanning electron microscopy (FIB-SEM) tomography, and observed the distribution pattern of ER contacts around the mammalian mitochondrial constriction site.Rat hepatocytes and HeLa cells were used. Liver tissue was obtained from male rats (Wistar, 6W) fixed by transcardial perfusion of 2% paraformaldehyde and 2.5% glutaraldehyde in 0.1 M cacodylate buffer (pH 7.4) under deep anesthesia. HeLa cells were fixed with the same fixative. The specimens were then stained en bloc to enhance membrane contrast and embedded in epoxy resin2). The surface of

  19. 4-Phenylbutyrate Benefits Traumatic Hemorrhagic Shock in Rats by Attenuating Oxidative Stress, Not by Attenuating Endoplasmic Reticulum Stress.

    PubMed

    Yang, Guangming; Peng, Xiaoyong; Hu, Yi; Lan, Dan; Wu, Yue; Li, Tao; Liu, Liangming

    2016-07-01

    Vascular dysfunction such as vascular hyporeactivity following severe trauma and shock is a major cause of death in injured patients. Oxidative stress and endoplasmic reticulum stress play an important role in vascular dysfunction. The objective of the present study was to determine whether or not 4-phenylbutyrate can improve vascular dysfunction and elicit antishock effects by inhibiting oxidative and endoplasmic reticulum stress. Prospective, randomized, controlled laboratory experiment. State key laboratory of trauma, burns, and combined injury. Five hundred and fifty-two Sprague-Dawley rats. Rats were anesthetized, and a model of traumatic hemorrhagic shock was established by left femur fracture and hemorrhage. The effects of 4-phenylbutyrate (5, 20, 50, 100, 200, and 300 mg/kg) on vascular reactivity, animal survival, hemodynamics, and vital organ function in traumatic hemorrhagic shock rats and cultured vascular smooth muscle cells, and the relationship to oxidative stress and endoplasmic reticulum stress was observed. Lower doses of 4-phenylbutyrate significantly improved the vascular function, stabilized the hemodynamics, and increased the tissue blood flow and vital organ function in traumatic hemorrhagic shock rats, and markedly improved the survival outcomes. Among all dosages observed in the present study, 20 mg/kg of 4-phenylbutyrate had the best effect. Further results indicated that 4-phenylbutyrate significantly inhibited the oxidative stress, decreased shock-induced oxidative stress index such as the production of reactive oxygen species, increased the antioxidant enzyme levels such as superoxide dismutase, catalase, and glutathione, and improved the mitochondrial function by inhibiting the opening of the mitochondrial permeability transition pore in rat artery and vascular smooth muscle cells. In contrast, 4-phenylbutyrate did not affect the changes of endoplasmic reticulum stress markers following traumatic hemorrhagic shock. Furthermore, 4

  20. An ultrathin, smooth, and low-loss Al-doped Ag film and its application as a transparent electrode in organic photovoltaics.

    PubMed

    Zhang, Cheng; Zhao, Dewei; Gu, Deen; Kim, Hyunsoo; Ling, Tao; Wu, Yi-Kuei Ryan; Guo, L Jay

    2014-08-27

    An ultrathin, smooth, and low-loss Ag film without a wetting layer is achieved by co-depositing a small amount of Al into Ag. The film can be as thin as 6 nm, with a roughness below 1 nm and excellent mechanical flexibility. Organic photovoltaics that use these thin films as transparent electrode show superior efficiency to their indium tin oxide (ITO) counterparts because of improved photon management.

  1. Structural reorganization of the fungal endoplasmic reticulum upon induction of mycotoxin biosynthesis

    PubMed Central

    Boenisch, Marike Johanne; Broz, Karen Lisa; Purvine, Samuel Owen; Chrisler, William Byron; Nicora, Carrie Diana; Connolly, Lanelle Reine; Freitag, Michael; Baker, Scott Edward; Kistler, Harold Corby

    2017-01-01

    Compartmentalization of metabolic pathways to particular organelles is a hallmark of eukaryotic cells. Knowledge of the development of organelles and attendant pathways under different metabolic states has been advanced by live cell imaging and organelle specific analysis. Nevertheless, relatively few studies have addressed the cellular localization of pathways for synthesis of fungal secondary metabolites, despite their importance as bioactive compounds with significance to medicine and agriculture. When triggered to produce sesquiterpene (trichothecene) mycotoxins, the endoplasmic reticulum (ER) of the phytopathogenic fungus Fusarium graminearum is reorganized both in vitro and in planta. Trichothecene biosynthetic enzymes accumulate in organized smooth ER with pronounced expansion at perinuclear- and peripheral positions. Fluorescence tagged trichothecene biosynthetic proteins co-localize with the modified ER as confirmed by co-fluorescence and co-purification with known ER proteins. We hypothesize that changes to the fungal ER represent a conserved process in specialized eukaryotic cells such as in mammalian hepatocytes and B-cells. PMID:28287158

  2. STUDIES ON THE ENDOPLASMIC RETICULUM

    PubMed Central

    Palade, George E.

    1955-01-01

    A survey of a large number of different cell types has indicated the presence of a network of membrane-bound cavities (the endoplasmic reticulum) in the cytoplasm of all cell types examined, with the exception of the mature erythrocyte. In its simplest form, encountered in seminal epithelia and in leucocytes, the reticulum consists mainly of interconnected strings of vesicles and appears to be randomly disposed in three dimensions. Local differentiations occur within the endoplasmic reticulum of all the cell types studied. The membrane limiting the cavities of the endoplasmic reticulum appears to be continuous with the cell membrane and the nuclear membranes. PMID:13278367

  3. [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.

  4. Smooth Sailing.

    ERIC Educational Resources Information Center

    Price, Beverley; Pincott, Maxine; Rebman, Ashley; Northcutt, Jen; Barsanti, Amy; Silkunas, Betty; Brighton, Susan K.; Reitz, David; Winkler, Maureen

    1999-01-01

    Presents discipline tips from several teachers to keep classrooms running smoothly all year. Some of the suggestions include the following: a bear-cave warning system, peer mediation, a motivational mystery, problem students acting as the teacher's assistant, a positive-behavior-reward chain, a hallway scavenger hunt (to ensure quiet passage…

  5. Smooth Sailing.

    ERIC Educational Resources Information Center

    Price, Beverley; Pincott, Maxine; Rebman, Ashley; Northcutt, Jen; Barsanti, Amy; Silkunas, Betty; Brighton, Susan K.; Reitz, David; Winkler, Maureen

    1999-01-01

    Presents discipline tips from several teachers to keep classrooms running smoothly all year. Some of the suggestions include the following: a bear-cave warning system, peer mediation, a motivational mystery, problem students acting as the teacher's assistant, a positive-behavior-reward chain, a hallway scavenger hunt (to ensure quiet passage…

  6. 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.

  7. The susceptibility of IMRT dose distributions to intrafraction organ motion: An investigation into smoothing filters derived from four dimensional computed tomography data

    SciTech Connect

    Coolens, Catherine; Evans, Phil M.; Seco, Joao; Webb, Steve; Blackall, Jane M.; Rietzel, Eike; Chen, George T. Y.

    2006-08-15

    This study investigated the sensitivity of static planning of intensity-modulated beams (IMBs) to intrafraction deformable organ motion and assessed whether smoothing of the IMBs at the treatment-planning stage can reduce this sensitivity. The study was performed with a 4D computed tomography (CT) data set for an IMRT treatment of a patient with liver cancer. Fluence profiles obtained from inverse-planning calculations on a standard reference CT scan were redelivered on a CT scan from the 4D data set at a different part of the breathing cycle. The use of a nonrigid registration model on the 4D data set additionally enabled detailed analysis of the overall intrafraction motion effects on the IMRT delivery during free breathing. Smoothing filters were then applied to the beam profiles within the optimization process to investigate whether this could reduce the sensitivity of IMBs to intrafraction organ motion. In addition, optimal fluence profiles from calculations on each individual phase of the breathing cycle were averaged to mimic the convolution of a static dose distribution with a motion probability kernel and assess its usefulness. Results from nonrigid registrations of the CT scan data showed a maximum liver motion of 7 mm in superior-inferior direction for this patient. Dose-volume histogram (DVH) comparison indicated a systematic shift when planning treatment on a motion-frozen, standard CT scan but delivering over a full breathing cycle. The ratio of the dose to 50% of the normal liver to 50% of the planning target volume (PTV) changed up to 28% between different phases. Smoothing beam profiles with a median-window filter did not overcome the substantial shift in dose due to a difference in breathing phase between planning and delivery of treatment. Averaging of optimal beam profiles at different phases of the breathing cycle mainly resulted in an increase in dose to the organs at risk (OAR) and did not seem beneficial to compensate for organ motion

  8. 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

  9. Endoplasmic Reticulum as a Site of Phenylpropanoid and Flavonoid Metabolism in Hippeastrum1

    PubMed Central

    Wagner, George J.; Hrazdina, Geza

    1984-01-01

    The nature of bound forms of enzymes of phenylpropanoid and flavonoid metabolism have been investigated in Hippeastrum CV Dutch Red Hybrid. Particulate components of petal homogenates were fractionated on sucrose gradients and the EDTA shift method was employed to characterize membranes of the endoplasmic reticulum. In magnesiumcontaining gradients, a portion of phenylalanine ammonia lyase, chalcone synthase, glucosyl transferase, and all of the trans-cinnamate 4-monooxygenase and NADH Cytochrome c reductase (the last an endoplasmic reticulum marker) were associated with membranes equilibrating at 1.18 specific gravity. In gradients lacking magnesium and containing EDTA, the above activities—except chalcone synthase, which was lost—and protein were diminished at 1.18 specific gravity and enhanced at lower densities characteristic of membranes of the smooth endoplasmic reticulum. These results are consistent with the contention that endoplasmic reticulum is a site of phenylpropanoid and flavonoid metabolism in Hippeastrum. PMID:16663530

  10. Spectrin alpha is important for rear polarization of the microtubule organizing center during migration and spindle pole assembly during division of neointimal smooth muscle cells.

    PubMed

    Silverman-Gavrila, Rosalind V; Silverman-Gavrila, Lorelei B; Bilal, Khawaja Hasan; Bendeck, Michelle P

    2015-04-01

    Directed migration of smooth muscle cells (SMCs) from the media to the intima and their subsequent proliferation are key events in atherosclerosis as these cells contribute to the bulk and stability of atheromatous plaques. We showed previously that two cytoskeleton-associated proteins, RHAMM and ARPC5, play important roles in rear polarization of the microtubule organizing centre (MTOC), directed migration, and in maintaining cell division fidelity. These proteins were analyzed to predict additional potential interacting partners using the bioinformatics programs BLAST, ClustalW, and PPI Spider. We identified spectrin alpha, a protein with a known role in actin polymerization as part of the pathway. We show that in migrating SMCs spectrin alpha localizes at the nodes of the actin net, and it partially colocalizes with RHAMM in the perinuclear region. In dividing SMCs spectrin alpha is present at spindle poles and midbody. Moreover, we show that spectrin alpha and RHAMM interact in a complex. Using siRNA to knockdown spectrin disrupted SMC migration, MTOC polarization, and the assembly of a polygonal actin net dorsolateral of the nucleus. Spectrin alpha knockdown also disrupted the organization of the bipolar spindle, chromosome division, and cytokinesis during cell division. The identification of interacting partners such as spectrin alpha and the decoding of pathways involved in polarity regulation during the migration of smooth muscle cells in atherosclerosis is important for identifying atherosclerosis biomarkers and developing therapeutic agents to block atherosclerotic plaque formation.

  11. Disruption of actin cytoskeleton mediates loss of tensile stress induced early phenotypic modulation of vascular smooth muscle cells in organ culture.

    PubMed

    Zheng, Jian-Pu; Ju, Donghong; Shen, Jianbin; Yang, Maozhou; Li, Li

    2010-02-01

    Aorta organ culture has been widely used as an ex vivo model for studying vessel pathophysiology. Recent studies show that the vascular smooth muscle cells (VSMCs) in organ culture undergo drastic dedifferentiation within the first few hours (termed early phenotypic modulation). Loss of tensile stress to which aorta is subject in vivo is the cause of this early phenotypic modulation. However, no underlying molecular mechanism has been discovered thus far. The purpose of the present study is to identify intracellular signals involved in the early phenotypic modulation of VSMC in organ culture. We find that the drastic VSMC dedifferentiation is accompanied by accelerated actin cytoskeleton dynamics and downregulation of SRF and myocardin. Among the variety of signal pathways examined, increasing actin polymerization by jasplakinolide is the only one hindering VSMC dedifferentiation in organ culture. Moreover, jasplakinolide reverses actin dynamics during organ culture. Latrunculin B (disrupting actin cytoskeleton) and jasplakinolide respectively suppressed and enhanced the expression of VSMC markers, SRF, myocardin, and CArG-box-mediated SMC promoters in PAC1, a VSMC line. These results identify actin cytoskeleton degradation as a major intracellular signal for loss of tensile stress-induced early phenotypic modulation of VSMC in organ culture. This study suggests that disrupting actin cytoskeleton integrity may contribute to the pathogenesis of vascular diseases. Published by Elsevier Inc.

  12. Effects of endothelial removal and regeneration on smooth muscle glycosaminoglycan synthesis and growth in rat carotid artery in organ culture

    SciTech Connect

    Merrilees, M.J.; Scott, L.J.

    1985-04-01

    Segments of rat carotid artery were maintained in serum-free and serum-supplemented media with endothelium both present and substantially removed by air drying. At intervals of 3, 7, and 14 days the synthesis of glycosaminoglycan across the vessel walls was determined by autoradiographic detection of incorporated (/sup 3/H)glucosamine. In control carotids the typical pattern of incorporation was 40% of label in the intima, consisting of endothelium and subendothelial matrix, 23, 13, and 15% in the three medial layers (M1, M2, M3, respectively), and 9% in the adventitia. During the first week in culture the proportion, and often the amount, of label in M1 increased significantly. Following air drying labeling decreased markedly in M1 but often increased in M2 and M3. By 14 days residual endothelial cells had regenerated, and the pattern of incorporation in the medial layers beneath this new endothelium was the same as for the controls with a high level of labeling in M1. In areas free of endothelium incorporation in M1 remained at a low level. Digestion with chondroitinase ABC and Streptomyces hyaluronidase showed that the changes in M1-labeling levels were due to changes in the amounts of both hyaluronic acid and sulfated glycosaminoglycan, whereas pulse and continuous labeling studies showed that the different labeling levels for the various layers and conditions were due to different rates of synthesis and not degradation. Carotids were also labeled with (/sup 3/H)thymidine. Control and regenerating endothelia were active in serum- free and serum-supplemented media and had similar mitotic indices. Indices for smooth muscle cells in M1, however, were generally very low and were not affected by the presence or absence of endothelium.

  13. Determination of the Young's modulus of the epicuticle of the smooth adhesive organs of Carausius morosus using tensile testing.

    PubMed

    Bennemann, Michael; Backhaus, Stefan; Scholz, Ingo; Park, Daesung; Mayer, Joachim; Baumgartner, Werner

    2014-10-15

    Adhesive organs like arolia of insects allow these animals to climb on different substrates by creating high adhesion forces. According to the Dahlquist criterion, adhesive organs must be very soft, exhibiting an effective Young's modulus of below 100 kPa to adhere well to substrates. Such a low effective Young's modulus allows the adhesive organs to make almost direct contact with the substrate and results in van der Waals forces along with capillary forces. In previous studies, the effective Young's moduli of adhesive organs were determined using indentation tests, revealing their structure to be very soft. However, adhesive organs show a layered structure, thus the measured values comprise the effective Young's moduli of several layers of the adhesive organs. In this study, a new approach is illustrated to measure the Young's modulus of the outermost layer of the arolium, i.e. of the epicuticle, of the stick insect Carausius morosus. As a result of the epicuticle being supported by upright fibres, tensile tests allow the determination of the Young's modulus of the epicuticle with hardly influence from subjacent layers. In our tensile tests, arolia of stick insects adhering on a latex membrane were stretched by stretching the membrane while the elongation of the contact area between an arolium and the membrane was recorded. For analysis, mathematical models of the mechanical system were developed. When fed with the observed elongations, these models yield estimates for the Young's modulus of the epicuticle of approximately 100 MPa. Thus, in arolia, a very thin layer (~225 nm) of a rather stiff material, which is less susceptible to abrasion, makes contact with the substrates, whereas the inner fibrous structure of arolia is responsible for their softness.

  14. Relationship of the Topological Distances and Activities between mPGES-1 and COX-2 versus COX-1: Implications of the Different Post-Translational Endoplasmic Reticulum Organizations of COX-1 and COX-2.

    PubMed

    Akasaka, Hironari; So, Shui-Ping; Ruan, Ke-He

    2015-06-16

    In vascular inflammation, prostaglandin E2 (PGE₂) is largely biosynthesized by microsomal PGE₂ synthase-1 (mPGES-1), competing with other downstream eicosanoid-synthesizing enzymes, such as PGIS, a synthase of a vascular protector prostacyclin (PGI₂), to isomerize the cyclooxygenase (COX)-2-derived prostaglandin H2 (PGH₂). In this study, we found that a majority of the product from the cells co-expressing human COX-2, mPGES-1, and PGIS was PGE₂. We hypothesize that the molecular and cellular mechanisms are related to the post-translational endoplasmic reticulum (ER) arrangement of those enzymes. A set of fusion enzymes, COX-2-linker [10 amino acids (aa)]-PGIS and COX-2-linker (22 amino acids)-PGIS, were created as "The Bioruler", in which the 10 and 22 amino acids are defined linkers with known helical structures and distances (14.4 and 30.8 Å, respectively). Our experiments have shown that the efficiency of PGI₂ biosynthesis was reduced when the separation distance increased from 10 to 22 amino acids. When COX-2-10aa-PGIS (with a 14.4 Å separation) was co-expressed with mPGES-1 on the ER membrane, a major product was PGE₂, but not PGI₂. However, expression of COX-2-10aa-PGIS and mPGES-1 on a separated ER with a distance of ≫30.8 Å reduced the level of PGE₂ production. These data indicated that the mPGES-1 is "complex-likely" colocalized with COX-2 within a distance of 14.4 Å. In addition, the cells co-expressing COX-1-10aa-PGIS and mPGES-1 produced PGI₂ mainly, but not PGE₂. This indicates that mPGES-1 is expressed much farther from COX-1. These findings have led to proposed models showing the different post-translational ER organization between COX-2 and COX-1 with respect to the topological arrangement of the mPGES-1 during vascular inflammation.

  15. Photoelectrochemical water splitting and simultaneous photoelectrocatalytic degradation of organic pollutant on highly smooth and ordered TiO{sub 2} nanotube arrays

    SciTech Connect

    Wu Hongjun; Zhang Zhonghai

    2011-12-15

    The photoelectrochemical water splitting and simultaneous photoelectrocatalytic degradation of organic pollutant were achieved on TiO{sub 2} nanotube electrodes with double purposes of environmental protection and renewable energy production under illumination of simulated solar light. The TiO{sub 2} nanotube arrays (TiO{sub 2} NTs) were fabricated by a two-step anodization method. The TiO{sub 2} NTs prepared in two-step anodization process (2-step TiO{sub 2} NTs) showed much better surface smoothness and tube orderliness than TiO{sub 2} NTs prepared in one-step anodization process (1-step TiO{sub 2} NTs). In the photoelectrochemical water splitting and simultaneous photoelectrocatalytic decomposition process, the 2-step TiO{sub 2} NTs electrode showed both highest photo-conversion efficiency of 1.25% and effective photodecomposition efficiency with existing of methylene blue (MB) as sacrificial agent and as pollutant target. Those results implied that the highly ordered nanostructures provided direct pathway and uniform electric field distribution for effective charges transfer, as well as superior capabilities of light harvesting. - Graphical Abstract: The photoelectrochemical water splitting for hydrogen generation and simultaneous photoelectrocatalytic degradation of organic pollutant (methylene blue) were achieved on TiO{sub 2} nanotube electrodes with double purposes of environmental protection and renewable energy production under illumination of simulated solar light. Highlights: Black-Right-Pointing-Pointer TiO{sub 2} nanotube arrays were fabricated by a two-step anodization method. Black-Right-Pointing-Pointer Hydrogen generation and organic pollutant degradation were achieved on TiO{sub 2} NTs. Black-Right-Pointing-Pointer Highest photoconversion efficiency of 1.25% was achieved. Black-Right-Pointing-Pointer Increasing orderliness will increase photocatalytic activity of TiO{sub 2} NTs.

  16. 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.

  17. Endoplasmic Reticulum Stress and Obesity.

    PubMed

    Yilmaz, Erkan

    2017-01-01

    In recent years, the world has seen an alarming increase in obesity and closely associated with insulin resistance which is a state of low-grade inflammation, the latter characterized by elevated levels of proinflammatory cytokines in blood and tissues. A shift in energy balance alters systemic metabolic regulation and the important role that chronic inflammation, endoplasmic reticulum (ER) dysfunction, and activation of the unfolded protein response (UPR) play in this process.Why obesity is so closely associated with insulin resistance and inflammation is not understood well. This suggests that there are probably other causes for obesity-related insulin resistance and inflammation. One of these appears to be endoplasmic reticulum (ER) stress.The ER is a vast membranous network responsible for the trafficking of a wide range of proteins and plays a central role in integrating multiple metabolic signals critical in cellular homeostasis. Conditions that may trigger unfolded protein response activation include increased protein synthesis, the presence of mutant or misfolded proteins, inhibition of protein glycosylation, imbalance of ER calcium levels, glucose and energy deprivation, hypoxia, pathogens or pathogen-associated components and toxins. Thus, characterizing the mechanisms contributing to obesity and identifying potential targets for its prevention and treatment will have a great impact on the control of associated conditions, particularly T2D.

  18. Brain Endoplasmic Reticulum Stress Mechanistically Distinguishes the Saline-Intake and Hypertensive Response to DOCA-Salt

    PubMed Central

    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.

    2015-01-01

    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 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 CHOP, 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 CHOP-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 CHOP-deficient mice, but these mice exhibited a normal hypertensive response. We conclude: 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 SFO which when attenuated by GRP78 blunts saline intake, and 3) CHOP 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 mediating effects of DOCA-salt on saline intake and blood pressure. PMID:25895586

  19. 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.

  20. Modeling of axonal endoplasmic reticulum network by spastic paraplegia proteins.

    PubMed

    Yalçın, Belgin; Zhao, Lu; Stofanko, Martin; O'Sullivan, Niamh C; Kang, Zi Han; Roost, Annika; Thomas, Matthew R; Zaessinger, Sophie; Blard, Olivier; Patto, Alex L; Sohail, Anood; Baena, Valentina; Terasaki, Mark; O'Kane, Cahir J

    2017-07-25

    Axons contain a smooth tubular endoplasmic reticulum (ER) network that is thought to be continuous with ER throughout the neuron; the mechanisms that form this axonal network are unknown. Mutations affecting reticulon or REEP proteins, with intramembrane hairpin domains that model ER membranes, cause an axon degenerative disease, hereditary spastic paraplegia (HSP). We show that Drosophila axons have a dynamic axonal ER network, which these proteins help to model. Loss of HSP hairpin proteins causes ER sheet expansion, partial loss of ER from distal motor axons, and occasional discontinuities in axonal ER. Ultrastructural analysis reveals an extensive ER network in axons, which shows larger and fewer tubules in larvae that lack reticulon and REEP proteins, consistent with loss of membrane curvature. Therefore HSP hairpin-containing proteins are required for shaping and continuity of axonal ER, thus suggesting roles for ER modeling in axon maintenance and function.

  1. 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.

  2. Isolation and characterization of the Neurospora crassa endoplasmic reticulum.

    PubMed Central

    Borgeson, C E; Bowman, B J

    1983-01-01

    The endoplasmic reticulum from Neurospora crassa was identified by monitoring the activity of the putative enzyme marker phosphatidylcholine glyceride transferase. After differential centrifugation of a cell homogenate, phosphatidylcholine glyceride transferase activity initially copurified with plasma membrane H+-ATPase. However, isopycnic centrifugation of the whole-cell homogenate on a linear sucrose gradient separated the two enzyme activities into different fractions. The lighter membrane fraction exhibited characteristics that have been associated with the endoplasmic reticulum in other organisms: (i) the inclusion of magnesium caused this light membrane fraction to shift to a higher density on the gradient; (ii) it was highly enriched in cytochrome c reductase, an endoplasmic reticulum marker in other systems; and (iii) the morphology of the light fraction with and without added magnesium was clearly distinguishable from that of the plasma membrane fraction by electron microscopy. A reinvestigation of the location of chitin synthetase confirmed its association with the plasma membrane fraction even after separation of the lighter fractions. Images PMID:6311800

  3. 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

  4. [Pharmacological studies of antispasmodics. III. Antispasmodic activity of 3-(di-2-thienylmethylene)-5-methyl-trans-quino-lizidinium bromide (HRS-902) on smooth muscle organs and its organ selectivity (author's transl)].

    PubMed

    Kubo, S; Morikawa, K; Matsubara, I; Yamazaki, M; Kato, H

    1981-01-01

    Pharmacological activities of HSR-902, a new antispasmodic agent, in gastrointestinal tract, biliary and urinary systems were compared with those of atropine, butylscopolamine bromide, timepidium bromide, prifinium bromide and diphemanil methylsulfate. In isolated smooth muscle organs (stomach, duodenum, ileum, colon, gall bladder and urinary bladder), anti-acetylcholine activities of HSR-902 were the most potent among these agents but its activity in urinary bladder, similar to findings in the cases of atropine and diphemanil methylsulfate, was relatively less potent than that of prifinium bromide, timepidium bromide and butylscopolamine bromide. Regarding the contractions of stomach, jejunum and ileum, which were induced by vagus nerve stimulation or acetylcholine, and on the ileum spontaneous motility, antispasmodic activities of HSR-902 were almost equal to or somewhat more potent than those of atropine, and its activities were more potent than those of prifinium bromide, timepidium bromide, diphemanil methylsulfate and butylscopolamine bromide. On the gall bladder pressure and the counts of perfusion through Oddi's Sphincter, these agents exhibited a similar inhibition and enhancement, respectively. In the case of urinary bladder contractions induced by pelvic nerve stimulation, these agents exhibited a weak inhibition. The inhibitory effect of HSR-902 was relatively less potent than that of other agents except atropine, which had little effect. HSR-902 was similar to atropine in this so-called "atropine-resistance".

  5. Endoplasmic reticulum–mitochondria contacts: function of the junction

    PubMed Central

    Rowland, Ashley A.; Voeltz, Gia K.

    2016-01-01

    The most well-characterized organelle contact sites are those between the endoplasmic reticulum (ER) and mitochondria. Increased understanding is being gained of how ER–mitochondria contact sites are organized and which factors converge at this interface, some of which may provide a tethering function. The role of the ER–mitochondria junction in coordinating the functions of these two organelles is also becoming clearer, and it has been shown to be involved in the regulation of lipid synthesis, Ca2+ signalling and the control of mitochondrial biogenesis and intracellular trafficking. PMID:22992592

  6. ARCHITECTURE AND NERVE SUPPLY OF MAMMALIAN SMOOTH MUSCLE TISSUE

    PubMed Central

    Caesar, Rudolf; Edwards, George A.; Ruska, Helmut

    1957-01-01

    Smooth muscle tissue from mouse urinary bladder, uterus, and gall bladder has been studied by means of the electron microscope. The smooth muscle cells are distinctly and completely separated from each other by a cytolemma comparable to the sarcolemma of striated muscle. The tissue is thus cellular and not syncytial. With this evidence, supported by electron microscopy of other tissues, we question the existence of true syncytia in animal tissues. Individual cell membranes necessary for the electrophysiologic events exist in smooth muscle, and its nerve and conduction in a tissue such as uterus or bladder can occur at the cellular level as well as at the tissue area level. The smooth muscle cell contains myofilaments, nucleus, endoplasmic reticulum, mitochondria, Golgi complex, centrosome, and pinocytotic vesicles. These structures are described in some detail, and their probable interrelations and functions are discussed. The autonomic nerves innervating smooth muscle cells are composed of axons and lemnoblasts. The axon is suspended by the mesaxon formed by the infolded plasma membrane of the lemnoblast. The respective plasma membranes separate axon and lemnoblast from each other and from surrounding muscle cells. The axons of autonomic nerves never penetrate the plasma membrane of the muscle cell, but pass or intrude into muscle cell pockets, forming a contact between axonal plasma membrane and smooth muscle plasma membrane. The lemnoblast shows well developed endoplasmic reticulum with Palade granules, mitochondria, and a long, elliptical nucleus. The axon contains neurofilaments, mitochondria, and synaptic vesicles; the quantity of the latter two being significantly greater in the periphery of lemnoblasts and near axon-muscle contact regions. We regard the contact regions as the synapses between the autonomic nerves and the smooth muscle cells. PMID:13481021

  7. Smoothed square well potential

    NASA Astrophysics Data System (ADS)

    Salamon, P.; Vertse, T.

    2017-07-01

    The classical square well potential is smoothed with a finite range smoothing function in order to get a new simple strictly finite range form for the phenomenological nuclear potential. The smoothed square well form becomes exactly zero smoothly at a finite distance, in contrast to the Woods-Saxon form. If the smoothing range is four times the diffuseness of the Woods-Saxon shape both the central and the spin-orbit terms of the Woods-Saxon shape are reproduced reasonably well. The bound single-particle energies in a Woods-Saxon potential can be well reproduced with those in the smoothed square well potential. The same is true for the complex energies of the narrow resonances.

  8. 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.

  9. Smoothing error pitfalls

    NASA Astrophysics Data System (ADS)

    von Clarmann, T.

    2014-04-01

    The difference due to the content of a priori information between a constrained retrieval and the true atmospheric state is usually represented by the so-called smoothing error. In this paper it is shown that the concept of the smoothing error is questionable because it is not compliant with Gaussian error propagation. The reason for this is that the smoothing error does not represent the expected deviation of the retrieval from the true state but the expected deviation of the retrieval from the atmospheric state sampled on an arbitrary grid, which is itself a smoothed representation of the true state. The idea of a sufficiently fine sampling of this reference atmospheric state is untenable because atmospheric variability occurs on all scales, implying that there is no limit beyond which the sampling is fine enough. Even the idealization of infinitesimally fine sampling of the reference state does not help because the smoothing error is applied to quantities which are only defined in a statistical sense, which implies that a finite volume of sufficient spatial extent is needed to meaningfully talk about temperature or concentration. Smoothing differences, however, which play a role when measurements are compared, are still a useful quantity if the involved a priori covariance matrix has been evaluated on the comparison grid rather than resulting from interpolation. This is, because the undefined component of the smoothing error, which is the effect of smoothing implied by the finite grid on which the measurements are compared, cancels out when the difference is calculated.

  10. Stopping smooth pursuit.

    PubMed

    Missal, Marcus; Heinen, Stephen J

    2017-04-19

    If a visual object of interest suddenly starts to move, we will try to follow it with a smooth movement of the eyes. This smooth pursuit response aims to reduce image motion on the retina that could blur visual perception. In recent years, our knowledge of the neural control of smooth pursuit initiation has sharply increased. However, stopping smooth pursuit eye movements is less well understood and will be discussed in this paper. The most straightforward way to study smooth pursuit stopping is by interrupting image motion on the retina. This causes eye velocity to decay exponentially towards zero. However, smooth pursuit stopping is not a passive response, as shown by behavioural and electrophysiological evidence. Moreover, smooth pursuit stopping is particularly influenced by active prediction of the upcoming end of the target. Here, we suggest that a particular class of inhibitory neurons of the brainstem, the omnipause neurons, could play a central role in pursuit stopping. Furthermore, the role of supplementary eye fields of the frontal cortex in smooth pursuit stopping is also discussed.This article is part of the themed issue 'Movement suppression: brain mechanisms for stopping and stillness'. © 2017 The Author(s).

  11. Quantum State Smoothing

    NASA Astrophysics Data System (ADS)

    Guevara, Ivonne; Wiseman, Howard

    2015-10-01

    Smoothing is an estimation method whereby a classical state (probability distribution for classical variables) at a given time is conditioned on all-time (both earlier and later) observations. Here we define a smoothed quantum state for a partially monitored open quantum system, conditioned on an all-time monitoring-derived record. We calculate the smoothed distribution for a hypothetical unobserved record which, when added to the real record, would complete the monitoring, yielding a pure-state "quantum trajectory." Averaging the pure state over this smoothed distribution yields the (mixed) smoothed quantum state. We study how the choice of actual unraveling affects the purity increase over that of the conventional (filtered) state conditioned only on the past record.

  12. Quantum State Smoothing.

    PubMed

    Guevara, Ivonne; Wiseman, Howard

    2015-10-30

    Smoothing is an estimation method whereby a classical state (probability distribution for classical variables) at a given time is conditioned on all-time (both earlier and later) observations. Here we define a smoothed quantum state for a partially monitored open quantum system, conditioned on an all-time monitoring-derived record. We calculate the smoothed distribution for a hypothetical unobserved record which, when added to the real record, would complete the monitoring, yielding a pure-state "quantum trajectory." Averaging the pure state over this smoothed distribution yields the (mixed) smoothed quantum state. We study how the choice of actual unraveling affects the purity increase over that of the conventional (filtered) state conditioned only on the past record.

  13. Diamond Smoothing Tools

    NASA Technical Reports Server (NTRS)

    Voronov, Oleg

    2007-01-01

    Diamond smoothing tools have been proposed for use in conjunction with diamond cutting tools that are used in many finish-machining operations. Diamond machining (including finishing) is often used, for example, in fabrication of precise metal mirrors. A diamond smoothing tool according to the proposal would have a smooth spherical surface. For a given finish machining operation, the smoothing tool would be mounted next to the cutting tool. The smoothing tool would slide on the machined surface left behind by the cutting tool, plastically deforming the surface material and thereby reducing the roughness of the surface, closing microcracks and otherwise generally reducing or eliminating microscopic surface and subsurface defects, and increasing the microhardness of the surface layer. It has been estimated that if smoothing tools of this type were used in conjunction with cutting tools on sufficiently precise lathes, it would be possible to reduce the roughness of machined surfaces to as little as 3 nm. A tool according to the proposal would consist of a smoothing insert in a metal holder. The smoothing insert would be made from a diamond/metal functionally graded composite rod preform, which, in turn, would be made by sintering together a bulk single-crystal or polycrystalline diamond, a diamond powder, and a metallic alloy at high pressure. To form the spherical smoothing tip, the diamond end of the preform would be subjected to flat grinding, conical grinding, spherical grinding using diamond wheels, and finally spherical polishing and/or buffing using diamond powders. If the diamond were a single crystal, then it would be crystallographically oriented, relative to the machining motion, to minimize its wear and maximize its hardness. Spherically polished diamonds could also be useful for purposes other than smoothing in finish machining: They would likely also be suitable for use as heat-resistant, wear-resistant, unlubricated sliding-fit bearing inserts.

  14. Targeting of OSBP-related protein 3 (ORP3) to endoplasmic reticulum and plasma membrane is controlled by multiple determinants

    SciTech Connect

    Lehto, Markku; Hynynen, Riikka; Karjalainen, Katja; Kuismanen, Esa; Hyvaerinen, Kati; Olkkonen, Vesa M. . E-mail: vesa.olkkonen@ktl.fi

    2005-11-01

    The intracellular targeting determinants of oxysterol binding protein (OSBP)-related protein 3 (ORP3) were studied using a series of truncated and point mutated constructs. The pleckstrin homology (PH) domain of ORP3 binds the phosphoinositide-3-kinase (PI3K) products, PI(3,4)P{sub 2} and PI(3,4,5)P{sub 3}. A functional PH domain and flanking sequences are crucial for the plasma membrane (PM) targeting of ORP3. The endoplasmic reticulum (ER) targeting of ORP3 is regulated the by a FFAT motif (EFFDAxE), which mediates interaction with VAMP-associated protein (VAP)-A. The targeting function of the FFAT motif dominates over that of the PH domain. In addition, the exon 10/11 region modulates interaction of ORP3 with the ER and the nuclear membrane. Analysis of a chimeric ORP3:OSBP protein suggests that ligand binding by the C-terminal domain of OSBP induces allosteric changes that activate the N-terminal targeting modules of ORP3. Notably, over-expression of ORP3 together with VAP-A induces stacked ER membrane structures also known as organized smooth ER (OSER). Moreover, lipid starvation promotes formation of dilated peripheral ER (DPER) structures dependent on the ORP3 protein. Based on the present data, we introduce a model for the inter-relationships of the functional domains of ORP3 in the membrane targeting of the protein.

  15. Discrete square root smoothing.

    NASA Technical Reports Server (NTRS)

    Kaminski, P. G.; Bryson, A. E., Jr.

    1972-01-01

    The basic techniques applied in the square root least squares and square root filtering solutions are applied to the smoothing problem. Both conventional and square root solutions are obtained by computing the filtered solutions, then modifying the results to include the effect of all measurements. A comparison of computation requirements indicates that the square root information smoother (SRIS) is more efficient than conventional solutions in a large class of fixed interval smoothing problems.

  16. Smoothing error pitfalls

    NASA Astrophysics Data System (ADS)

    von Clarmann, T.

    2014-09-01

    The difference due to the content of a priori information between a constrained retrieval and the true atmospheric state is usually represented by a diagnostic quantity called smoothing error. In this paper it is shown that, regardless of the usefulness of the smoothing error as a diagnostic tool in its own right, the concept of the smoothing error as a component of the retrieval error budget is questionable because it is not compliant with Gaussian error propagation. The reason for this is that the smoothing error does not represent the expected deviation of the retrieval from the true state but the expected deviation of the retrieval from the atmospheric state sampled on an arbitrary grid, which is itself a smoothed representation of the true state; in other words, to characterize the full loss of information with respect to the true atmosphere, the effect of the representation of the atmospheric state on a finite grid also needs to be considered. The idea of a sufficiently fine sampling of this reference atmospheric state is problematic because atmospheric variability occurs on all scales, implying that there is no limit beyond which the sampling is fine enough. Even the idealization of infinitesimally fine sampling of the reference state does not help, because the smoothing error is applied to quantities which are only defined in a statistical sense, which implies that a finite volume of sufficient spatial extent is needed to meaningfully discuss temperature or concentration. Smoothing differences, however, which play a role when measurements are compared, are still a useful quantity if the covariance matrix involved has been evaluated on the comparison grid rather than resulting from interpolation and if the averaging kernel matrices have been evaluated on a grid fine enough to capture all atmospheric variations that the instruments are sensitive to. This is, under the assumptions stated, because the undefined component of the smoothing error, which is the

  17. Modeling of axonal endoplasmic reticulum network by spastic paraplegia proteins

    PubMed Central

    Yalçın, Belgin; Zhao, Lu; Stofanko, Martin; O'Sullivan, Niamh C; Kang, Zi Han; Roost, Annika; Thomas, Matthew R; Zaessinger, Sophie; Blard, Olivier; Patto, Alex L; Sohail, Anood; Baena, Valentina; Terasaki, Mark; O'Kane, Cahir J

    2017-01-01

    Axons contain a smooth tubular endoplasmic reticulum (ER) network that is thought to be continuous with ER throughout the neuron; the mechanisms that form this axonal network are unknown. Mutations affecting reticulon or REEP proteins, with intramembrane hairpin domains that model ER membranes, cause an axon degenerative disease, hereditary spastic paraplegia (HSP). We show that Drosophila axons have a dynamic axonal ER network, which these proteins help to model. Loss of HSP hairpin proteins causes ER sheet expansion, partial loss of ER from distal motor axons, and occasional discontinuities in axonal ER. Ultrastructural analysis reveals an extensive ER network in axons, which shows larger and fewer tubules in larvae that lack reticulon and REEP proteins, consistent with loss of membrane curvature. Therefore HSP hairpin-containing proteins are required for shaping and continuity of axonal ER, thus suggesting roles for ER modeling in axon maintenance and function. DOI: http://dx.doi.org/10.7554/eLife.23882.001 PMID:28742022

  18. 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

    2010-03-05

    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.

  19. Transport and transporters in the endoplasmic reticulum.

    PubMed

    Csala, Miklós; Marcolongo, Paola; Lizák, Beáta; Senesi, Silvia; Margittai, Eva; Fulceri, Rosella; Magyar, Judit E; Benedetti, Angelo; Bánhegyi, Gábor

    2007-06-01

    Enzyme activities localized in the luminal compartment of the endoplasmic reticulum are integrated into the cellular metabolism by transmembrane fluxes of their substrates, products and/or cofactors. Most compounds involved are bulky, polar or even charged; hence, they cannot be expected to diffuse through lipid bilayers. Accordingly, transport processes investigated so far have been found protein-mediated. The selective and often rate-limiting transport processes greatly influence the activity, kinetic features and substrate specificity of the corresponding luminal enzymes. Therefore, the phenomenological characterization of endoplasmic reticulum transport contributes largely to the understanding of the metabolic functions of this organelle. Attempts to identify the transporter proteins have only been successful in a few cases, but recent development in molecular biology promises a better progress in this field.

  20. 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

  1. Endoplasmic reticulum stress: The cause and solution to Huntington's disease?

    PubMed

    Jiang, Yuwei; Chadwick, Sarah R; Lajoie, Patrick

    2016-10-01

    Accumulation of misfolded proteins is a hallmark of many human diseases, including several incurable neurological disorders, such as Huntington's disease (HD). In HD, expansion of a polyglutamine stretch within the first exon of the Huntingtin protein (Htt) leads to Htt misfolding, aberrant protein aggregation, and progressive appearance of disease symptoms. Several studies in various organisms (from yeast to humans) have identified the accumulation of misfolded secretory proteins in the endoplasmic reticulum (ER stress) as a crucial determinant of cellular toxicity in HD. In this review, we highlight the recent research linking HD to ER stress. We also discuss how the modulation of signaling pathways responsible for coping with misfolded protein accumulation in the ER may constitute attractive methods to reduce toxicity and identify new therapeutic targets for treatment of HD. This article is part of a Special Issue entitled SI:ER stress.

  2. Plant Endoplasmic Reticulum-Plasma Membrane Contact Sites.

    PubMed

    Wang, Pengwei; Hawes, Chris; Hussey, Patrick J

    2017-04-01

    The endoplasmic reticulum (ER) acts as a superhighway with multiple sideroads that connects the different membrane compartments including the ER to the plasma membrane (PM). ER-PM contact sites (EPCSs) are a common feature in eukaryotic organisms, but have not been studied well in plants owing to the lack of molecular markers and to the difficulty in resolving the EPCS structure using conventional microscopy. Recently, however, plant protein complexes required for linking the ER and PM have been identified. This is a further step towards understanding the structure and function of plant EPCSs. We highlight some recent studies in this field and suggest several hypotheses that relate to the possible function of EPCSs in plants.

  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. Smoothly deformed light

    NASA Technical Reports Server (NTRS)

    Stenholm, Stig

    1993-01-01

    A single mode cavity is deformed smoothly to change its electromagnetic eigenfrequency. The system is modeled as a simple harmonic oscillator with a varying period. The Wigner function of the problem is obtained exactly by starting with a squeezed initial state. The result is evaluated for a linear change of the cavity length. The approach to the adiabatic limit is investigated. The maximum squeezing is found to occur for smooth change lasting only a fraction of the oscillational period. However, only a factor of two improvement over the adiabatic result proves to be possible. The sudden limit cannot be investigated meaningfully within the model.

  5. Proliferation and Morphogenesis of the Endoplasmic Reticulum Driven by the Membrane Domain of 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase in Plant Cells1[OPEN

    PubMed Central

    Ferrero, Sergi; Grados-Torrez, Ricardo Enrique; Antolín-Llovera, Meritxell; López-Iglesias, Carmen; Cortadellas, Nuria; Ferrer, Joan Carles

    2015-01-01

    The enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) has a key regulatory role in the mevalonate pathway for isoprenoid biosynthesis and is composed of an endoplasmic reticulum (ER)-anchoring membrane domain with low sequence similarity among eukaryotic kingdoms and a conserved cytosolic catalytic domain. Organized smooth endoplasmic reticulum (OSER) structures are common formations of hypertrophied tightly packed ER membranes devoted to specific biosynthetic and secretory functions, the biogenesis of which remains largely unexplored. We show that the membrane domain of plant HMGR suffices to trigger ER proliferation and OSER biogenesis. The proliferating membranes become highly enriched in HMGR protein, but they do not accumulate sterols, indicating a morphogenetic rather than a metabolic role for HMGR. The N-terminal MDVRRRPP motif present in most plant HMGR isoforms is not required for retention in the ER, which was previously proposed, but functions as an ER morphogenic signal. Plant OSER structures are morphologically similar to those of animal cells, emerge from tripartite ER junctions, and mainly build up beside the nuclear envelope, indicating conserved OSER biogenesis in high eukaryotes. Factors other than the OSER-inducing HMGR construct mediate the tight apposition of the proliferating membranes, implying separate ER proliferation and membrane association steps. Overexpression of the membrane domain of Arabidopsis (Arabidopsis thaliana) HMGR leads to ER hypertrophy in every tested cell type and plant species, whereas the knockout of the HMG1 gene from Arabidopsis, encoding its major HMGR isoform, causes ER aggregation at the nuclear envelope. Our results show that the membrane domain of HMGR contributes to ER morphogenesis in plant cells. PMID:26015445

  6. Proliferation and Morphogenesis of the Endoplasmic Reticulum Driven by the Membrane Domain of 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase in Plant Cells.

    PubMed

    Ferrero, Sergi; Grados-Torrez, Ricardo Enrique; Leivar, Pablo; Antolín-Llovera, Meritxell; López-Iglesias, Carmen; Cortadellas, Nuria; Ferrer, Joan Carles; Campos, Narciso

    2015-07-01

    The enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) has a key regulatory role in the mevalonate pathway for isoprenoid biosynthesis and is composed of an endoplasmic reticulum (ER)-anchoring membrane domain with low sequence similarity among eukaryotic kingdoms and a conserved cytosolic catalytic domain. Organized smooth endoplasmic reticulum (OSER) structures are common formations of hypertrophied tightly packed ER membranes devoted to specific biosynthetic and secretory functions, the biogenesis of which remains largely unexplored. We show that the membrane domain of plant HMGR suffices to trigger ER proliferation and OSER biogenesis. The proliferating membranes become highly enriched in HMGR protein, but they do not accumulate sterols, indicating a morphogenetic rather than a metabolic role for HMGR. The N-terminal MDVRRRPP motif present in most plant HMGR isoforms is not required for retention in the ER, which was previously proposed, but functions as an ER morphogenic signal. Plant OSER structures are morphologically similar to those of animal cells, emerge from tripartite ER junctions, and mainly build up beside the nuclear envelope, indicating conserved OSER biogenesis in high eukaryotes. Factors other than the OSER-inducing HMGR construct mediate the tight apposition of the proliferating membranes, implying separate ER proliferation and membrane association steps. Overexpression of the membrane domain of Arabidopsis (Arabidopsis thaliana) HMGR leads to ER hypertrophy in every tested cell type and plant species, whereas the knockout of the HMG1 gene from Arabidopsis, encoding its major HMGR isoform, causes ER aggregation at the nuclear envelope. Our results show that the membrane domain of HMGR contributes to ER morphogenesis in plant cells. © 2015 American Society of Plant Biologists. All Rights Reserved.

  7. Cyclosporine triggers endoplasmic reticulum stress in endothelial cells: a role for endothelial phenotypic changes and death.

    PubMed

    Bouvier, Nicolas; Flinois, Jean Pierre; Gilleron, Jerome; Sauvage, François-Ludovic; Legendre, Christophe; Beaune, Philippe; Thervet, Eric; Anglicheau, Dany; Pallet, Nicolas

    2009-01-01

    Calcineurin inhibitors cyclosporine and tacrolimus are effective immunosuppressants, but both substances have the same intrinsic nephrotoxic potential that adversely affects allograft survival in renal transplant patients and causes end-stage renal disease in other solid organ or bone marrow transplant recipients. Endothelial cells are the first biological interface between drugs and the kidney, and calcineurin inhibitors may influence endothelial function and viability in a number of ways. Notably, endothelial cells have recently been shown to contribute to the accumulation of interstitial fibroblasts in nonrenal models, through endothelial-to-mesenchymal transition. Here we demonstrate that cyclosporine, but not tacrolimus or its metabolites, induces morphological and phenotypic endothelial changes suggestive of a partial endothelial-to-mesenchymal transition in human umbilical arterial endothelial cells. We identify for the first time a contingent of interstitial myofibroblasts that coexpress endothelial markers in rat kidneys treated with cyclosporine, suggesting that endothelial-to-mesenchymal transition could occur in vivo. Finally, our findings suggest that endoplasmic reticulum stress triggered by cyclosporine induces endothelial cells to undergo endothelial phenotypic changes suggestive of a partial endothelial-to-mesenchymal transition, whereas salubrinal partially preserves the endothelial phenotype. Inversely, tacrolimus does not induce endothelial-to-mesenchymal transition or endoplasmic reticulum stress. In conclusion, this study demonstrates for the first time that cyclosporine, and not tacrolimus, induces endoplasmic reticulum stress in endothelial cells. Our findings also suggest that endoplasmic reticulum stress contributes to endothelial cell death and phenotypic changes similar to a partial endothelial-to-mesenchymal transition.

  8. Smoothed Particle Hydrodynamic Simulator

    SciTech Connect

    2016-10-05

    This code is a highly modular framework for developing smoothed particle hydrodynamic (SPH) simulations running on parallel platforms. The compartmentalization of the code allows for rapid development of new SPH applications and modifications of existing algorithms. The compartmentalization also allows changes in one part of the code used by many applications to instantly be made available to all applications.

  9. Hummocky and Smooth Plains

    NASA Image and Video Library

    2000-01-15

    This image, from NASA Mariner 10 spacecraft which launched in 1974, is located about 500 km east of the Caloris basin and shows hummocky plains interpreted as Caloris ejecta in the upper half of the picture and smooth plains in the lower half.

  10. Smoothing non-smooth systems with low-pass filters

    NASA Astrophysics Data System (ADS)

    Hook, James

    2014-02-01

    Low pass filters, which are used to remove high frequency noise from time series data, smooth the signals they are applied to. In this paper we examine the action of low pass filters on discontinuous or non-differentiable signals from non-smooth dynamical systems. We show that the application of such a filter is equivalent to a change of variables, which transforms the non-smooth system into a smooth one. We examine this smoothing action on a variety of examples and demonstrate how it is useful in the calculation of a non-smooth system's Lyapunov spectrum.

  11. 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

  12. Improvement of device performance of polymer organic light-emitting diodes on smooth transparent sheet with graphene films synthesized by plasma treatment

    NASA Astrophysics Data System (ADS)

    Okigawa, Yuki; Mizutani, Wataru; Suzuki, Kenkichi; Ishihara, Masatou; Yamada, Takatoshi; Hasegawa, Masataka

    2015-09-01

    Because graphene films have one-atom thickness, the morphology of the transparent sheets could have a greater effect on the performance of organic light-emitting diode (OLED) devices with graphene films than on that with indium tin oxide (ITO). In this study, we have evaluated the polymer OLED devices with graphene films synthesized by plasma treatment on poly(ethylene terephthalate) (PET) and poly(ethylene naphthalate) (PEN) sheets having high flatness. The results imply that the surface roughness of the transparent sheets predominantly affects the luminescence of polymer OLED devices with graphene films. The suppression of leakage current and a luminescence higher than 8000 cd/m2 at 15 V were attained for the devices on the transparent sheet with higher flatness in spite of the presence of large sharp spikes.

  13. Review of Theoretical Prediction Models for Organic Extract Metabolites, Effect of Drying Temperature on Smooth Muscle Relaxing Activity Induced by Organic Extracts Specially Cecropia Obtusifolia Portal and Web Server Predictors of Drug-Protein Interaction.

    PubMed

    Aguirre-Crespo, Francisco; García-Mera, Xerardo; Guillén-Poot, Mónica Anahi; May-Díaz, Héctor Fernado; Tun-Suárez, Adrián; Aguirre-Crespo, A; Hernández-Rodríguez, J; Vergara-Galicia, Jorge; Rodríguez-López, V; Prado-Prado, Francisco J

    2015-02-19

    Cecropia obtusifolia bertol is medicinal specie used in the treatment of diabetes mellitus and hypertension and it has scientific studies that support the traditional use. However, it is required to understand the influence of drying temperature on the yield and pharmacological activity. Drying rate, extraction efficiency, changes in the UV-Vis spectrum and estimating chlorophylls were stimulated with the increasing temperature. Finally, relaxant activity of vascular smooth muscle is increased by 70ºC and reducing ability by the method of CARF increases with temperature. Analytical studies are required to identify changes in the metabolic content and those that ensure the safety and efficacy for human consumption. In this sense, bioinformatic studies may be helpful. Studies such as QSAR can help us to study these metabolites derived from natural products. MIND-BETS model and NL MIND-BETS model to predict DPIs was introduced using MARCH-INSIDE (MI) software to calculate structural parameters for drugs and enzymes respectively. We firstly revised the state-of-art on the design with review of previous works with hypertension activity based on theoretical studies. A study, evaluating the effect of drying temperature of leaves of C. obtusifolia on the relaxing of vascular smooth muscle, antioxidant activity and the presence of chlorophylls, with a focus on Cecropia metabolites. Last, we carried out QSAR studies using MIND-BEST and NL MIND-BEST web servers in order to understand the essential metabolites structural requirement for binding with receptors for FDA proteins.

  14. Influence of surface smoothing on spin Seebeck effect of Ce1Y2Fe5O12 deposited by metal organic decomposition

    NASA Astrophysics Data System (ADS)

    Hirata, Satoshi; Ono, Tatsuyoshi; Amemiya, Yoshiteru; Tabei, Tetsuo; Yokoyama, Shin

    2017-04-01

    Thus far, Bi1Y2Fe5O12 (Bi:YIG) films deposited by metal organic decomposition (MOD) are mainly used for magnetic insulation film of spin Seebeck devices. In order to increase the power conversion efficiency of these devices, we focused on Ce1Y2Fe5O12 (Ce:YIG), which has a larger Faraday rotation than Bi:YIG. Since there has been no report, except for the patent document, concerning the deposition of Ce:YIG films by MOD, we investigated the appropriate annealing temperatures, and we found that Ce:YIG films are crystallized when the annealing temperature is over 800 °C. However, since no electromotive force has been observed, we checked the surface roughness of Ce:YIG films by atomic force microscopy (AFM). Since their surfaces of Ce:YIG films were very rough, it was mechanically polished (MP). Then, an electromotive force of, at most, 11.3 µV was generated. This is the first report concerning the spin Seebeck effect of Ce:YIG deposited by MOD.

  15. Globular adiponectin reduces vascular calcification via inhibition of ER-stress-mediated smooth muscle cell apoptosis.

    PubMed

    Lu, Yan; Bian, Yunfei; Wang, Yueru; Bai, Rui; Wang, Jiapu; Xiao, Chuanshi

    2015-01-01

    This study aims to explore the mechanism of globular adiponectin inhibiting vascular calcification. We established drug-induced rat vascular calcification model, globular adiponectin was given to observe the effect of globular Adiponectin on the degree of calcification. The markers of vascular calcification and apoptosis were also investigated. Meanwhile, the in vitro effect of globular Adiponectin on vascular calcification was also evaluated using primary cultured rat vascular smooth muscle cells. We found that globular adiponectin could inhibit drug-induced rat vascular calcification significantly in vivo. The apoptosis of vascular smooth muscle cells was also reduced. The possible mechanism could be the down-regulation of endoplasmic reticulum stress by globular adiponectin. Experiments in primary cultured vascular smooth muscle cells also confirmed that globular adiponectin could reduce cell apoptosis to suppress vascular calcification via inhibition of endoplasmic reticulum stress. This study confirmed that globular adiponectin could suppress vascular calcification; one of the mechanisms could be inhibition of endoplasmic reticulum stress to reduce cell apoptosis. It could provide an effective method in the therapy of vascular calcification-associated diseases.

  16. Globular adiponectin reduces vascular calcification via inhibition of ER-stress-mediated smooth muscle cell apoptosis

    PubMed Central

    Lu, Yan; Bian, Yunfei; Wang, Yueru; Bai, Rui; Wang, Jiapu; Xiao, Chuanshi

    2015-01-01

    Objective: This study aims to explore the mechanism of globular adiponectin inhibiting vascular calcification. Methods: We established drug-induced rat vascular calcification model, globular adiponectin was given to observe the effect of globular Adiponectin on the degree of calcification. The markers of vascular calcification and apoptosis were also investigated. Meanwhile, the in vitro effect of globular Adiponectin on vascular calcification was also evaluated using primary cultured rat vascular smooth muscle cells. Results: We found that globular adiponectin could inhibit drug-induced rat vascular calcification significantly in vivo. The apoptosis of vascular smooth muscle cells was also reduced. The possible mechanism could be the down-regulation of endoplasmic reticulum stress by globular adiponectin. Experiments in primary cultured vascular smooth muscle cells also confirmed that globular adiponectin could reduce cell apoptosis to suppress vascular calcification via inhibition of endoplasmic reticulum stress. Conclusions: This study confirmed that globular adiponectin could suppress vascular calcification; one of the mechanisms could be inhibition of endoplasmic reticulum stress to reduce cell apoptosis. It could provide an effective method in the therapy of vascular calcification-associated diseases. PMID:26045760

  17. The Mammalian Endoplasmic Reticulum-Associated Degradation System

    PubMed Central

    Olzmann, James A.; Kopito, Ron R.; Christianson, John C.

    2013-01-01

    The endoplasmic reticulum (ER) is the site of synthesis for nearly one-third of the eukaryotic proteome and is accordingly endowed with specialized machinery to ensure that proteins deployed to the distal secretory pathway are correctly folded and assembled into native oligomeric complexes. Proteins failing to meet this conformational standard are degraded by ER-associated degradation (ERAD), a complex process through which folding-defective proteins are selected and ultimately degraded by the ubiquitin-proteasome system. ERAD proceeds through four tightly coupled steps involving substrate selection, dislocation across the ER membrane, covalent conjugation with polyubiquitin, and proteasomal degradation. The ERAD machinery shows a modular organization with central ER membrane-embedded ubiquitin ligases linking components responsible for recognition in the ER lumen to the ubiquitin-proteasome system in the cytoplasm. The core ERAD machinery is highly conserved among eukaryotes and much of our basic understanding of ERAD organization has been derived from genetic and biochemical studies of yeast. In this article we discuss how the core ERAD machinery is organized in mammalian cells. PMID:23232094

  18. Anti-smooth muscle antibody

    MedlinePlus

    ... medlineplus.gov/ency/article/003531.htm Anti-smooth muscle antibody To use the sharing features on this page, please enable JavaScript. Anti-smooth muscle antibody is a blood test that detects the ...

  19. Smooth Phase Interpolated Keying

    NASA Technical Reports Server (NTRS)

    Borah, Deva K.

    2007-01-01

    Smooth phase interpolated keying (SPIK) is an improved method of computing smooth phase-modulation waveforms for radio communication systems that convey digital information. SPIK is applicable to a variety of phase-shift-keying (PSK) modulation schemes, including quaternary PSK (QPSK), octonary PSK (8PSK), and 16PSK. In comparison with a related prior method, SPIK offers advantages of better performance and less complexity of implementation. In a PSK scheme, the underlying information waveform that one seeks to convey consists of discrete rectangular steps, but the spectral width of such a waveform is excessive for practical radio communication. Therefore, the problem is to smooth the step phase waveform in such a manner as to maintain power and bandwidth efficiency without incurring an unacceptably large error rate and without introducing undesired variations in the amplitude of the affected radio signal. Although the ideal constellation of PSK phasor points does not cause amplitude variations, filtering of the modulation waveform (in which, typically, a rectangular pulse is converted to a square-root raised cosine pulse) causes amplitude fluctuations. If a power-efficient nonlinear amplifier is used in the radio communication system, the fluctuating-amplitude signal can undergo significant spectral regrowth, thus compromising the bandwidth efficiency of the system. In the related prior method, one seeks to solve the problem in a procedure that comprises two major steps: phase-value generation and phase interpolation. SPIK follows the two-step approach of the related prior method, but the details of the steps are different. In the phase-value-generation step, the phase values of symbols in the PSK constellation are determined by a phase function that is said to be maximally smooth and that is chosen to minimize the spectral spread of the modulated signal. In this step, the constellation is divided into two groups by assigning, to information symbols, phase values

  20. Effects of hydrogen sulphide in smooth muscle.

    PubMed

    Dunn, William R; Alexander, Stephen P H; Ralevic, Vera; Roberts, Richard E

    2016-02-01

    In recent years, it has become apparent that the gaseous pollutant, hydrogen sulphide (H2S) can be synthesised in the body and has a multitude of biological actions. This review summarizes some of the actions of this 'gasotransmitter' in influencing the smooth muscle that is responsible for controlling muscular activity of hollow organs. In the vasculature, while H2S can cause vasoconstriction by complex interactions with other biologically important gases, such as nitric oxide, the prevailing response is vasorelaxation. While most vasorelaxation responses occur by a direct action of H2S on smooth muscle cells, it has recently been proposed to be an endothelium-derived hyperpolarizing factor. H2S also promotes relaxation in other smooth muscle preparations including bronchioles, the bladder, gastrointestinal tract and myometrium, opening up the opportunity of exploiting the pharmacology of H2S in the treatment of conditions where smooth muscle tone is excessive. The original concept, that H2S caused smooth muscle relaxation by activating ATP-sensitive K(+) channels, has been supplemented with observations that H2S can also modify the activity of other potassium channels, intracellular pH, phosphodiesterase activity and transient receptor potential channels on sensory nerves. While the enzymes responsible for generating endogenous H2S are widely expressed in smooth muscle preparations, it is much less clear what the physiological role of H2S is in determining smooth muscle contractility. Clarification of this requires the development of potent and selective inhibitors of H2S-generating enzymes. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Mechanics of Vascular Smooth Muscle.

    PubMed

    Ratz, Paul H

    2015-12-15

    Vascular smooth muscle (VSM; see Table 1 for a list of abbreviations) is a heterogeneous biomaterial comprised of cells and extracellular matrix. By surrounding tubes of endothelial cells, VSM forms a regulated network, the vasculature, through which oxygenated blood supplies specialized organs, permitting the development of large multicellular organisms. VSM cells, the engine of the vasculature, house a set of regulated nanomotors that permit rapid stress-development, sustained stress-maintenance and vessel constriction. Viscoelastic materials within, surrounding and attached to VSM cells, comprised largely of polymeric proteins with complex mechanical characteristics, assist the engine with countering loads imposed by the heart pump, and with control of relengthening after constriction. The complexity of this smart material can be reduced by classical mechanical studies combined with circuit modeling using spring and dashpot elements. Evaluation of the mechanical characteristics of VSM requires a more complete understanding of the mechanics and regulation of its biochemical parts, and ultimately, an understanding of how these parts work together to form the machinery of the vascular tree. Current molecular studies provide detailed mechanical data about single polymeric molecules, revealing viscoelasticity and plasticity at the protein domain level, the unique biological slip-catch bond, and a regulated two-step actomyosin power stroke. At the tissue level, new insight into acutely dynamic stress-strain behavior reveals smooth muscle to exhibit adaptive plasticity. At its core, physiology aims to describe the complex interactions of molecular systems, clarifying structure-function relationships and regulation of biological machines. The intent of this review is to provide a comprehensive presentation of one biomachine, VSM.

  2. Interstitial Cells: Regulators of Smooth Muscle Function

    PubMed Central

    Sanders, Kenton M.; Ward, Sean M.; Koh, Sang Don

    2014-01-01

    Smooth muscles are complex tissues containing a variety of cells in addition to muscle cells. Interstitial cells of mesenchymal origin interact with and form electrical connectivity with smooth muscle cells in many organs, and these cells provide important regulatory functions. For example, in the gastrointestinal tract, interstitial cells of Cajal (ICC) and PDGFRα+ cells have been described, in detail, and represent distinct classes of cells with unique ultrastructure, molecular phenotypes, and functions. Smooth muscle cells are electrically coupled to ICC and PDGFRα+ cells, forming an integrated unit called the SIP syncytium. SIP cells express a variety of receptors and ion channels, and conductance changes in any type of SIP cell affect the excitability and responses of the syncytium. SIP cells are known to provide pacemaker activity, propagation pathways for slow waves, transduction of inputs from motor neurons, and mechanosensitivity. Loss of interstitial cells has been associated with motor disorders of the gut. Interstitial cells are also found in a variety of other smooth muscles; however, in most cases, the physiological and pathophysiological roles for these cells have not been clearly defined. This review describes structural, functional, and molecular features of interstitial cells and discusses their contributions in determining the behaviors of smooth muscle tissues. PMID:24987007

  3. Interstitial cells: regulators of smooth muscle function.

    PubMed

    Sanders, Kenton M; Ward, Sean M; Koh, Sang Don

    2014-07-01

    Smooth muscles are complex tissues containing a variety of cells in addition to muscle cells. Interstitial cells of mesenchymal origin interact with and form electrical connectivity with smooth muscle cells in many organs, and these cells provide important regulatory functions. For example, in the gastrointestinal tract, interstitial cells of Cajal (ICC) and PDGFRα(+) cells have been described, in detail, and represent distinct classes of cells with unique ultrastructure, molecular phenotypes, and functions. Smooth muscle cells are electrically coupled to ICC and PDGFRα(+) cells, forming an integrated unit called the SIP syncytium. SIP cells express a variety of receptors and ion channels, and conductance changes in any type of SIP cell affect the excitability and responses of the syncytium. SIP cells are known to provide pacemaker activity, propagation pathways for slow waves, transduction of inputs from motor neurons, and mechanosensitivity. Loss of interstitial cells has been associated with motor disorders of the gut. Interstitial cells are also found in a variety of other smooth muscles; however, in most cases, the physiological and pathophysiological roles for these cells have not been clearly defined. This review describes structural, functional, and molecular features of interstitial cells and discusses their contributions in determining the behaviors of smooth muscle tissues.

  4. The Pathogen-Occupied Vacuoles of Anaplasma phagocytophilum and Anaplasma marginale Interact with the Endoplasmic Reticulum.

    PubMed

    Truchan, Hilary K; Cockburn, Chelsea L; Hebert, Kathryn S; Magunda, Forgivemore; Noh, Susan M; Carlyon, Jason A

    2016-01-01

    The genus Anaplasma consists of tick-transmitted obligate intracellular bacteria that invade white or red blood cells to cause debilitating and potentially fatal infections. A. phagocytophilum, a human and veterinary pathogen, infects neutrophils to cause granulocytic anaplasmosis. A. marginale invades bovine erythrocytes. Evidence suggests that both species may also infect endothelial cells in vivo. In mammalian and arthropod host cells, A. phagocytophilum and A. marginale reside in host cell derived pathogen-occupied vacuoles (POVs). While it was recently demonstrated that the A. phagocytophilum-occupied vacuole (ApV) intercepts membrane traffic from the trans-Golgi network, it is unclear if it or the A. marginale-occupied vacuole (AmV) interacts with other secretory organelles. Here, we demonstrate that the ApV and AmV extensively interact with the host endoplasmic reticulum (ER) in endothelial, myeloid, and/or tick cells. ER lumen markers, calreticulin, and protein disulfide isomerase, and the ER membrane marker, derlin-1, were pronouncedly recruited to the peripheries of both POVs. ApV association with the ER initiated early and continued throughout the infection cycle. Both the ApV and AmV interacted with the rough ER and smooth ER. However, only derlin-1-positive rough ER derived vesicles were delivered into the ApV lumen where they localized with intravacuolar bacteria. Transmission electron microscopy identified multiple ER-POV membrane contact sites on the cytosolic faces of both species' vacuoles that corresponded to areas on the vacuoles' lumenal faces where intravacuolar Anaplasma organisms closely associated. A. phagocytophilum is known to hijack Rab10, a GTPase that regulates ER dynamics and morphology. Yet, ApV-ER interactions were unhindered in cells in which Rab10 had been knocked down, demonstrating that the GTPase is dispensable for the bacterium to parasitize the ER. These data establish the ApV and AmV as pathogen-host interfaces that directly

  5. Incompressible smoothed particle hydrodynamics

    SciTech Connect

    Ellero, Marco Serrano, Mar; Espanol, Pep

    2007-10-01

    We present a smoothed particle hydrodynamic model for incompressible fluids. As opposed to solving a pressure Poisson equation in order to get a divergence-free velocity field, here incompressibility is achieved by requiring as a kinematic constraint that the volume of the fluid particles is constant. We use Lagrangian multipliers to enforce this restriction. These Lagrange multipliers play the role of non-thermodynamic pressures whose actual values are fixed through the kinematic restriction. We use the SHAKE methodology familiar in constrained molecular dynamics as an efficient method for finding the non-thermodynamic pressure satisfying the constraints. The model is tested for several flow configurations.

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

    PubMed

    Ariyasu, Daisuke; Yoshida, Hiderou; Hasegawa, Yukihiro

    2017-02-11

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

  7. Endoplasmic reticulum: ER stress regulates mitochondrial bioenergetics

    PubMed Central

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

    2014-01-01

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

  8. Protein quality control at the endoplasmic reticulum.

    PubMed

    McCaffrey, Kathleen; Braakman, Ineke

    2016-10-15

    The ER (endoplasmic reticulum) is the protein folding 'factory' of the secretory pathway. Virtually all proteins destined for the plasma membrane, the extracellular space or other secretory compartments undergo folding and maturation within the ER. The ER hosts a unique PQC (protein quality control) system that allows specialized modifications such as glycosylation and disulfide bond formation essential for the correct folding and function of many secretory proteins. It is also the major checkpoint for misfolded or aggregation-prone proteins that may be toxic to the cell or extracellular environment. A failure of this system, due to aging or other factors, has therefore been implicated in a number of serious human diseases. In this article, we discuss several key features of ER PQC that maintain the health of the cellular secretome. © 2016 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  9. Endoplasmic Reticulum (ER) Stress and Endocrine Disorders

    PubMed Central

    Ariyasu, Daisuke; Yoshida, Hiderou; Hasegawa, Yukihiro

    2017-01-01

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

  10. 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

  11. 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

  12. An endoplasmic reticulum-specific cyclophilin.

    PubMed Central

    Hasel, K W; Glass, J R; Godbout, M; Sutcliffe, J G

    1991-01-01

    Cyclophilin is a ubiquitously expressed cytosolic peptidyl-prolyl cis-trans isomerase that is inhibited by the immunosuppressive drug cyclosporin A. A degenerate oligonucleotide based on a conserved cyclophilin sequence was used to isolate cDNA clones representing a ubiquitously expressed mRNA from mice and humans. This mRNA encodes a novel 20-kDa protein, CPH2, that shares 64% sequence identity with cyclophilin. Bacterially expressed CPH2 binds cyclosporin A and is a cyclosporin A-inhibitable peptidyl-prolyl cis-trans isomerase. Cell fractionation of rat liver followed by Western blot (immunoblot) analysis indicated that CPH2 is not cytosolic but rather is located exclusively in the endoplasmic reticulum. These results suggest that cyclosporin A mediates its effect on cells through more than one cyclophilin and that cyclosporin A-induced misfolding of T-cell membrane proteins normally mediated by CPH2 plays a role in immunosuppression. Images PMID:1710767

  13. Endoplasmic Reticulum Stress Response in Arabidopsis Roots

    PubMed Central

    Cho, Yueh; Kanehara, Kazue

    2017-01-01

    Roots are the frontier of plant body to perceive underground environmental change. Endoplasmic reticulum (ER) stress response represents circumvention of cellular stress caused by various environmental changes; however, a limited number of studies are available on the ER stress responses in roots. Here, we report the tunicamycin (TM) -induced ER stress response in Arabidopsis roots by monitoring expression patterns of immunoglobulin-binding protein 3 (BiP3), a representative marker for the response. Roots promptly responded to the TM-induced ER stress through the induction of similar sets of ER stress-responsive genes. However, not all cells responded uniformly to the TM-induced ER stress in roots, as BiP3 was highly expressed in root tips, an outer layer in elongation zone, and an inner layer in mature zone of roots. We suggest that ER stress response in roots has tissue specificity. PMID:28298914

  14. Endoplasmic Reticulum-Plasma Membrane Contact Sites.

    PubMed

    Saheki, Yasunori; De Camilli, Pietro

    2017-06-20

    The endoplasmic reticulum (ER) has a broad localization throughout the cell and forms direct physical contacts with all other classes of membranous organelles, including the plasma membrane (PM). A number of protein tethers that mediate these contacts have been identified, and study of these protein tethers has revealed a multiplicity of roles in cell physiology, including regulation of intracellular Ca(2+) dynamics and signaling as well as control of lipid traffic and homeostasis. In this review, we discuss the cross talk between the ER and the PM mediated by direct contacts. We review factors that tether the two membranes, their properties, and their dynamics in response to the functional state of the cell. We focus in particular on the role of ER-PM contacts in nonvesicular lipid transport between the two bilayers mediated by lipid transfer proteins.

  15. Endoplasmic reticulum stress and intestinal inflammation.

    PubMed

    Kaser, A; Blumberg, R S

    2010-01-01

    The intestinal epithelial cell (IEC) is increasingly recognized to play a prominent role as an important intermediary between the commensal microbiota and the intestinal immune system. Moreover, it is now recognized that intestinal inflammation in inflammatory bowel disease (IBD) may arise primarily from IEC dysfunction due to unresolved endoplasmic reticulum (ER) stress as a consequence of genetic disruption of X box binding protein-1 function. In addition to primary (genetic) abnormalities of the unfolded protein response, a variety of secondary (inflammation and environmental) factors are also likely to be important regulators of ER stress. ER stress pathways are also well known to regulate (and be regulated by) autophagy pathways. Therefore, the host's ability to manage ER stress is likely to be a major pathway in the pathogenesis of intestinal inflammation that arises primarily from the IEC. Herein we discuss ER stress in the IEC as both an originator and perpetuator of intestinal inflammation in IBD.

  16. Role of epidermal growth factor receptor and endoplasmic reticulum stress in vascular remodeling induced by angiotensin II.

    PubMed

    Takayanagi, Takehiko; Kawai, Tatsuo; Forrester, Steven J; Obama, Takashi; Tsuji, Toshiyuki; Fukuda, Yamato; Elliott, Katherine J; Tilley, Douglas G; Davisson, Robin L; Park, Joon-Young; Eguchi, Satoru

    2015-06-01

    The mechanisms by which angiotensin II (AngII) elevates blood pressure and enhances end-organ damage seem to be distinct. However, the signal transduction cascade by which AngII specifically mediates vascular remodeling such as medial hypertrophy and perivascular fibrosis remains incomplete. We have previously shown that AngII-induced epidermal growth factor receptor (EGFR) transactivation is mediated by disintegrin and metalloproteinase domain 17 (ADAM17), and that this signaling is required for vascular smooth muscle cell hypertrophy but not for contractile signaling in response to AngII. Recent studies have implicated endoplasmic reticulum (ER) stress in hypertension. Interestingly, EGFR is capable of inducing ER stress. The aim of this study was to test the hypothesis that activation of EGFR and ER stress are critical components required for vascular remodeling but not hypertension induced by AngII. Mice were infused with AngII for 2 weeks with or without treatment of EGFR inhibitor, erlotinib, or ER chaperone, 4-phenylbutyrate. AngII infusion induced vascular medial hypertrophy in the heart, kidney and aorta, and perivascular fibrosis in heart and kidney, cardiac hypertrophy, and hypertension. Treatment with erlotinib as well as 4-phenylbutyrate attenuated vascular remodeling and cardiac hypertrophy but not hypertension. In addition, AngII infusion enhanced ADAM17 expression, EGFR activation, and ER/oxidative stress in the vasculature, which were diminished in both erlotinib-treated and 4-phenylbutyrate-treated mice. ADAM17 induction and EGFR activation by AngII in vascular cells were also prevented by inhibition of EGFR or ER stress. In conclusion, AngII induces vascular remodeling by EGFR activation and ER stress via a signaling mechanism involving ADAM17 induction independent of hypertension. © 2015 American Heart Association, Inc.

  17. Endoplasmic reticulum-derived multilamellar bodies in oocytes of mouse follicle cultures under oxidized low-density lipoprotein treatment.

    PubMed

    Spanel-Borowski, Katharina; Nowicki, Marcin; Borlak, Juergen; Trapphoff, Tom; Eichenlaub-Ritter, Ursula

    2013-01-01

    Multilamellar bodies associated with an organized endoplasmic reticulum (ER) arise in various somatic cell types, and a subtype called multivesicular bodies is described in oocytes. Both entities, so far undetermined in significance, may occur in oocytes of follicles under oxidative stress. In preovulatory follicles, oxidative stress appears to be caused by oxidized low-density lipoprotein (ox-LDL). Cultures of preantral mouse follicles were treated with 100 µg/ml ox-LDL or normal LDL (n-LDL) for 12-48 h or for 12 days during antral follicle growth followed by in vitro ovulation and harvest of cumulus oophorus complexes (COCs) with metaphase II (MII) oocytes on day 13. Preantral follicles, COCs, or MII oocytes were immunostained with anti-tubulin antibody or stained with actin-binding phalloidin for confocal microscopy. Ultrathin sections were prepared for electron microscopy. Preantral follicles exposed to n-LDL or ox-LDL developed normally, and MII oocytes in COCs possessed normal spindles with well-aligned chromosomes. In contrast, treated cumulus cells underwent apoptosis. Only the ox-LDL-treated preantral follicle oocytes showed ER-derived multilamellar bodies (EMBs) of type I, consisting of rough ER membranes for the envelope. The MII oocytes of COCs showed type II EMBs consisting of smooth/vesicular ER and were more prominent after ox-LDL than after n-LDL exposure. Degenerating mitochondria were prominent in oocytes of the ox-LDL group and judged as a sign of oxidative stress. Oxidative stress presumably induces damage of proteins and organelles in the oocytes. The EMBs might sequester the damaged structures for oocyte survival. Thus, EMBs could represent a novel form of autophagy. Copyright © 2012 S. Karger AG, Basel.

  18. Endoplasmic Reticulum Stress Regulates Adipocyte Resistin Expression

    PubMed Central

    Lefterova, Martina I.; Mullican, Shannon E.; Tomaru, Takuya; Qatanani, Mohammed; Schupp, Michael; Lazar, Mitchell A.

    2009-01-01

    OBJECTIVE Resistin is a secreted polypeptide that impairs glucose metabolism and, in rodents, is derived exclusively from adipocytes. In murine obesity, resistin circulates at elevated levels but its gene expression in adipose tissue is paradoxically reduced. The mechanism behind the downregulation of resistin mRNA is poorly understood. We investigated whether endoplasmic reticulum (ER) stress, which is characteristic of obese adipose tissue, regulates resistin expression in cultured mouse adipocytes. RESEARCH DESIGN AND METHODS The effects of endoplasmic stress inducers on resistin mRNA and secreted protein levels were examined in differentiated 3T3-L1 adipocytes, focusing on the expression and genomic binding of transcriptional regulators of resistin. The association between downregulated resistin mRNA and induction of ER stress was also investigated in the adipose tissue of mice fed a high-fat diet. RESULTS ER stress reduced resistin mRNA in 3T3-L1 adipocytes in a time- and dose-dependent manner. The effects of ER stress were transcriptional because of downregulation of CAAT/enhancer binding protein-α and peroxisome proliferator–activated receptor-γ transcriptional activators and upregulation of the transcriptional repressor CAAT/enhancer binding protein homologous protein-10 (CHOP10). Resistin protein was also substantially downregulated, showing a close correspondence with mRNA levels in 3T3-L1 adipocytes as well as in the fat pads of obese mice. CONCLUSIONS ER stress is a potent regulator of resistin, suggesting that ER stress may underlie the local downregulation of resistin mRNA and protein in fat in murine obesity. The paradoxical increase in plasma may be because of various systemic abnormalities associated with obesity and insulin resistance. PMID:19491212

  19. Effect of Da-Cheng-Qi Decoction on the Repair of the Injured Enteric Nerve-Interstitial Cells of Cajal-Smooth Muscle Cells Network in Multiple Organ Dysfunction Syndrome

    PubMed Central

    Liu, Mu-Cang; Xie, Ming-Zheng; Ma, Bin; Qi, Qing-Hui

    2014-01-01

    Wistar rats were randomly divided into control group, multiple organ dysfunction syndrome (MODS) group, and Da-Cheng-Qi decoction (DCQD) group. The network of enteric nerves-interstitial cells of Cajal- (ICC-) smooth muscle cells (SMC) in small intestine was observed using confocal laser scanning microscopy and transmission electron microscopy. The results showed that the numbers of cholinergic/nitriergic nerves, and the deep muscular plexus of ICC (ICC-DMP) and connexin43 (Cx43) in small intestine with MODS were significantly decreased. The network integrity of enteric nerves-ICC-SMC was disrupted. The ultrastructures of ICC-DMP, enteric nerves, and SMC were severely damaged. After treatment with DCQD, the damages were repaired and the network integrity of enteric nerves ICC-SMC was significantly recovered. In conclusion, the pathogenesis of gastrointestinal motility dysfunction in MODS in part may be due to the damages to enteric nerves-ICC-SMC network and gap junctions. The therapeutic mechanism of DCQD in part may be that it could repair the damages and maintain the integrity of enteric nerves ICC-SMC network. PMID:25477993

  20. Proteostasis: bad news and good news from the endoplasmic reticulum.

    PubMed

    Noack, Julia; Brambilla Pisoni, Giorgia; Molinari, Maurizio

    2014-01-01

    The endoplasmic reticulum (ER) is an intracellular compartment dedicated to the synthesis and maturation of secretory and membrane proteins, totalling about 30% of the total eukaryotic cells proteome. The capacity to produce correctly folded polypeptides and to transport them to their correct intra- or extracellular destinations relies on proteostasis networks that regulate and balance the activity of protein folding, quality control, transport and degradation machineries. Nutrient and environmental changes, pathogen infection aging and, more relevant for the topics discussed in this review, mutations that impair attainment of the correct 3D structure of nascent polypeptide chains may compromise the activity of the proteostasis networks with devastating consequences on cells, organs and organisms' homeostasis. Here we present a review of mechanisms regulating folding and quality control of proteins expressed in the ER, and we describe the protein degradation and the ER stress pathways activated by the expression of misfolded proteins in the ER lumen. Finally, we highlight select examples of proteopathies (also known as conformational disorders or protein misfolding diseases) caused by protein misfolding in the ER and/or affecting cellular proteostasis and therapeutic interventions that might alleviate or cure the disease symptoms.

  1. INTERMEDIATE FILAMENTS IN SMOOTH MUSCLE

    PubMed Central

    Tang, Dale D.

    2008-01-01

    The intermediate filament (IF) network is one of the three cytoskeletal systems in smooth muscle. The type III IF proteins vimentin and desmin are major constituents of the network in smooth muscle cells and tissues. Lack of vimentin or desmin impairs contractile ability of various smooth muscle preparations, implying their important role for smooth muscle force development. The IF framework has long been viewed as a fixed cytostructure that solely provides mechanical integrity for the cell. However, recent studies suggest that the IF cytoskeleton is dynamic in mammalian cells in response to various external stimulation. In this review, the structure and biological properties of IF proteins in smooth muscle are summarized. The role of IF proteins in the modulation of smooth muscle force development and redistribution/translocation of signaling partners (such as p130 Crk-associated substrate, CAS) is depicted. This review also summarizes our latest understanding on how the IF network may be regulated in smooth muscle. PMID:18256275

  2. [Effect of safflower injection on endoplasmic reticulum stress-induced apoptosts in rats with hypoxic pulmonary hypertension].

    PubMed

    Fan, Xiao-Fang; Wang, Xue-Rui; Yuan, Gong-Sheng; Wu, Dong-Hong; Hu, Liang-Gang; Xue, Feng; Gong, Yong-Sheng

    2012-11-01

    To explore the effects of safflower injection on prevention and treatment of hypoxic pulmonary hypertension and clarify the function of the endoplasmic reticulum stress apoptosis pathway during the process. Thirty male SD rats were randomly grouped as normal control group, hypoxia-hypercapnia group and hypoxia+safflower group. The latter two groups were put in the cabin with oxygen concentration ranged from 9% to 11% and carbon dioxide concentration from 5% to 6%. The pulmonary artery pressure and the index of right ventricular hypertrophy were determined after hypoxia exposure (8 h/dx28 d). Changes in morphology of lung tissue were observed by electron microscopy. To explore the possible mechanisms, we also detected apoptosis and apoptosis-related genes/proteins in lung tissue by TUNEL reactivity and PCR and Western blot. Compared with the normal control group, pulmonary artery pressure and the index of right ventricular hypertrophy in hypoxia group were 45% and 33.4% higher, respectively. Tiny blood vessel wall of lungs was thickened and edema, and proliferation of collagen fibers was obvious under the electron microscope. TUNEL staining of apoptotic cells in lung tissues showed more high brightness green fluorescence (+-++), but less green fluorescence showed in the pulmonary vascular smooth muscle cell layer, and apoptosis index (AI) value was 150% higher; gene and protein expression levels of endoplasmic reticulum stress pathway were increased. Compared with hypoxia-hypercapnia group, pulmonary artery pressure and the index of right ventricular hypertrophy in the hypoxia+safflower group were 18% and 15.6% lower, respectively; collagen fibers were decreased, and smooth muscle cells and epithelial cells were got apoptotic-like changes under the electron microscope. TUNEL staining of apoptotic cells in lung tissues showed brighter green fluorescence (++-+++); the high brightness green fluorescence showed in pulmonary vascular smooth muscle cell layer, and

  3. Valosin-containing protein-interacting membrane protein (VIMP) links the endoplasmic reticulum with microtubules in concert with cytoskeleton-linking membrane protein (CLIMP)-63.

    PubMed

    Noda, Chikano; Kimura, Hana; Arasaki, Kohei; Matsushita, Mitsuru; Yamamoto, Akitsugu; Wakana, Yuichi; Inoue, Hiroki; Tagaya, Mitsuo

    2014-08-29

    The distribution and morphology of the endoplasmic reticulum (ER) in mammalian cells depend on both dynamic and static interactions of ER membrane proteins with microtubules (MTs). Cytoskeleton-linking membrane protein (CLIMP)-63 is exclusively localized in sheet-like ER membranes, typical structures of the rough ER, and plays a pivotal role in the static interaction with MTs. Our previous study showed that the 42-kDa ER-residing form of syntaxin 5 (Syn5L) regulates ER structure through the interactions with both CLIMP-63 and MTs. Here, we extend our previous study and show that the valosin-containing protein/p97-interacting membrane protein (VIMP)/SelS is also a member of the family of proteins that shape the ER by interacting with MTs. Depletion of VIMP causes the spreading of the ER to the cell periphery and affects an MT-dependent process on the ER. Although VIMP can interact with CLIMP-63 and Syn5L, it does not interact with MT-binding ER proteins (such as Reep1) that shape the tubular smooth ER, suggesting that different sets of MT-binding ER proteins are used to organize different ER subdomains. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  4. Valosin-containing Protein-interacting Membrane Protein (VIMP) Links the Endoplasmic Reticulum with Microtubules in Concert with Cytoskeleton-linking Membrane Protein (CLIMP)-63*

    PubMed Central

    Noda, Chikano; Kimura, Hana; Arasaki, Kohei; Matsushita, Mitsuru; Yamamoto, Akitsugu; Wakana, Yuichi; Inoue, Hiroki; Tagaya, Mitsuo

    2014-01-01

    The distribution and morphology of the endoplasmic reticulum (ER) in mammalian cells depend on both dynamic and static interactions of ER membrane proteins with microtubules (MTs). Cytoskeleton-linking membrane protein (CLIMP)-63 is exclusively localized in sheet-like ER membranes, typical structures of the rough ER, and plays a pivotal role in the static interaction with MTs. Our previous study showed that the 42-kDa ER-residing form of syntaxin 5 (Syn5L) regulates ER structure through the interactions with both CLIMP-63 and MTs. Here, we extend our previous study and show that the valosin-containing protein/p97-interacting membrane protein (VIMP)/SelS is also a member of the family of proteins that shape the ER by interacting with MTs. Depletion of VIMP causes the spreading of the ER to the cell periphery and affects an MT-dependent process on the ER. Although VIMP can interact with CLIMP-63 and Syn5L, it does not interact with MT-binding ER proteins (such as Reep1) that shape the tubular smooth ER, suggesting that different sets of MT-binding ER proteins are used to organize different ER subdomains. PMID:25008318

  5. Mouse Aorta Smooth Muscle Cells Differentiate Into Lymphoid Tissue Organizer-Like Cells on Combined Tumor Necrosis Factor Receptor-1/Lymphotoxin β-Receptor NF-κB Signaling

    PubMed Central

    Lötzer, Katharina; Döpping, Sandra; Connert, Sabine; Gräbner, Rolf; Spanbroek, Rainer; Lemser, Birgit; Beer, Michael; Hildner, Markus; Hehlgans, Thomas; van der Wall, Michael; Mebius, Reina E.; Lovas, Agnes; Randolph, Gwendalyn J.; Weih, Falk; Habenicht, Andreas J.R.

    2010-01-01

    Objective Mouse aorta smooth muscle cells (SMC) express tumor necrosis factor receptor superfamily member 1A (TNFR-1) and lymphotoxin β-receptor (LTβR). Circumstantial evidence has linked the SMC LTβR to tertiary lymphoid organogenesis in hyperlipidemic mice. Here, we explored TNFR-1 and LTβR signaling in cultured SMC. Methods and Results TNFR-1 signaling activated the classical RelA NF-κB pathway, whereas LTβR signaling activated the classical RelA and alternative RelB NF-κB pathways, and both signaling pathways synergized to enhance p100 inhibitor processing to the p52 subunit of NF-κB. Microarrays showed that simultaneous TNFR-1/LTβR activation resulted in elevated mRNA encoding leukocyte homeostatic chemokines CCL2, CCL5, CXCL1, and CX3CL1. Importantly, SMC acquired features of lymphoid tissue organizers, which control tertiary lymphoid organogenesis in autoimmune diseases through hyperinduction of CCL7, CCL9, CXCL13, CCL19, CXCL16, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1. TNFR-1/LTβR cross-talk resulted in augmented secretion of lymphorganogenic chemokine proteins. Supernatants of TNFR-1/LTβR–activated SMC markedly supported migration of splenic T cells, B cells, and macrophages/dendritic cells. Experiments with ltbr−/− SMC indicated that LTβR-RelB activation was obligatory to generate the lymphoid tissue organizer phenotype. Conclusion SMC may participate in the formation of tertiary lymphoid tissue in atherosclerosis by upregulation of lymphorganogenic chemokines involved in T-lymphocyte, B-lymphocyte, and macrophage/dendritic cell attraction. PMID:20139367

  6. 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.

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

    PubMed

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

    2016-01-01

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

  8. 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

  9. Restriction of docking protein to the rough endoplasmic reticulum: immunocytochemical localization in rat liver.

    PubMed

    Hortsch, M; Griffiths, G; Meyer, D I

    1985-09-01

    Docking protein (or SRP receptor) is an integral membrane protein essential for translocation of nascent polypeptides across the membrane of the endoplasmic reticulum (ER). Anti-docking protein antibodies were used to localize this protein in situ in thin frozen sections using protein A-gold detection methods. The majority of gold particles was restricted to ribosome-studded membranes, whereas particles were rarely seen in areas rich in smooth ER. Quantitative evaluation of labeling suggests that there is one molecule of docking protein for roughly 10 to 20 bound ribosomes. On the basis of these results we conclude that docking protein is the first functionally-characterized integral marker protein specific for the rough membranes of ER.

  10. Isolation of intracellular membranes by means of sodium carbonate treatment: application to endoplasmic reticulum

    PubMed Central

    1982-01-01

    A rapid and simple method for the isolation of membranes from subcellular organelles is described. The procedure consists of diluting the organelles in ice-cold 100 mM Na2CO3 followed by centrifugation to pellet the membranes. Closed vesicles are converted to open membrane sheets, and content proteins and peripheral membrane proteins are released in soluble form. Here we document the method by applying it to various subfractions of a rat liver microsomal fraction, prepared by continuous density gradient centrifugation according to Beaufay et al. (1974, J. Cell Biol. 61:213-231). The results confirm and extend those of previous investigators on the distribution of enzymes and proteins among the membranes of the smooth and rough endoplasmic reticulum. In the accompanying paper (1982, J. Cell Biol. 93:103-110) the procedure is applied to peroxisomes and mitochondria. PMID:7068762

  11. Hydrogen Sulfide Improves Vascular Calcification in Rats by Inhibiting Endoplasmic Reticulum Stress.

    PubMed

    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.

  12. 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. Copyright © 2011 Elsevier GmbH. All rights reserved.

  13. Diabetes: Targeting endoplasmic reticulum to combat juvenile diabetes.

    PubMed

    Urano, Fumihiko

    2014-03-01

    Limited options for clinical management of patients with juvenile-onset diabetes mellitus call for a novel therapeutic paradigm. Two innovative studies support endoplasmic reticulum as an emerging target for combating both autoimmune and heritable forms of this disease.

  14. Hydrogen sulfide, endoplasmic reticulum stress and alcohol mediated neurotoxicity.

    PubMed

    George, Akash K; Behera, Jyotirmaya; Kelly, Kimberly E; Zhai, Yuankun; Tyagi, Neetu

    2017-02-14

    Alcohol is one of the most socially accepted addictive drugs in modern society. Its abuse affects virtually all organ systems with the central nervous system (CNS) being particularly vulnerable to excessive alcohol exposure. Alcohol exposure also causes profound damage to both the adult and developing brain. Excessive alcohol consumption induces numerous pathophysiological stress responses, one of which is the endoplasmic reticulum (ER) stress response. Potential mechanisms that trigger the alcohol induced ER stress response are either directly or indirectly related to alcohol metabolism, which include toxic levels of acetaldehyde and homocysteine, oxidative stress and abnormal epigenetic modifications. Growing evidence suggests that H2S is the most recently recognized gasotransmitter with tremendous physiological protective functions against oxidative stress induced neurotoxicity. In this review we address the alcohol induced oxidative stress mediated ER stress and the role of H2S in its mitigation in the context of alcohol neurotoxicity. Interruption of ER stress triggers is anticipated to have therapeutic benefits for alcohol mediated diseases and disorders.

  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. The role of the endoplasmic reticulum in peroxisome biogenesis.

    PubMed

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

    2013-05-01

    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.

  17. Endoplasmic-reticulum-mediated microtubule alignment governs cytoplasmic streaming.

    PubMed

    Kimura, Kenji; Mamane, Alexandre; Sasaki, Tohru; Sato, Kohta; Takagi, Jun; Niwayama, Ritsuya; Hufnagel, Lars; Shimamoto, Yuta; Joanny, Jean-François; Uchida, Seiichi; Kimura, Akatsuki

    2017-04-01

    Cytoplasmic streaming refers to a collective movement of cytoplasm observed in many cell types. The mechanism of meiotic cytoplasmic streaming (MeiCS) in Caenorhabditis elegans zygotes is puzzling as the direction of the flow is not predefined by cell polarity and occasionally reverses. Here, we demonstrate that the endoplasmic reticulum (ER) network structure is required for the collective flow. Using a combination of RNAi, microscopy and image processing of C. elegans zygotes, we devise a theoretical model, which reproduces and predicts the emergence and reversal of the flow. We propose a positive-feedback mechanism, where a local flow generated along a microtubule is transmitted to neighbouring regions through the ER. This, in turn, aligns microtubules over a broader area to self-organize the collective flow. The proposed model could be applicable to various cytoplasmic streaming phenomena in the absence of predefined polarity. The increased mobility of cortical granules by MeiCS correlates with the efficient exocytosis of the granules to protect the zygotes from osmotic and mechanical stresses.

  18. 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.

  19. Autonomic modification of intestinal smooth muscle contractility.

    PubMed

    Montgomery, Laura E A; Tansey, Etain A; Johnson, Chris D; Roe, Sean M; Quinn, Joe G

    2016-03-01

    Intestinal smooth muscle contracts rhythmically in the absence of nerve and hormonal stimulation because of the activity of pacemaker cells between and within the muscle layers. This means that the autonomic nervous system modifies rather than initiates intestinal contractions. The practical described here gives students an opportunity to observe this spontaneous activity and its modification by agents associated with parasympathetic and sympathetic nerve activity. A section of the rabbit small intestine is suspended in an organ bath, and the use of a pressure transducer and data-acquisition software allows the measurement of tension generated by the smooth muscle of intestinal walls. The application of the parasympathetic neurotransmitter ACh at varying concentrations allows students to observe an increase in intestinal smooth muscle tone with increasing concentrations of this muscarinic receptor agonist. Construction of a concentration-effect curve allows students to calculate an EC50 value for ACh and consider some basic concepts surrounding receptor occupancy and activation. Application of the hormone epinephrine to the precontracted intestine allows students to observe the inhibitory effects associated with sympathetic nerve activation. Introduction of the drug atropine to the preparation before a maximal concentration of ACh is applied allows students to observe the inhibitory effect of a competitive antagonist on the physiological response to a receptor agonist. The final experiment involves the observation of the depolarizing effect of K(+) on smooth muscle. Students are also invited to consider why the drugs atropine, codeine, loperamide, and botulinum toxin have medicinal uses in the management of gastrointestinal problems.

  20. 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.

  1. Cancer: Untethering Mitochondria from the Endoplasmic Reticulum?

    PubMed Central

    Herrera-Cruz, Maria Sol; Simmen, Thomas

    2017-01-01

    Following the discovery of the mitochondria-associated membrane (MAM) as a hub for lipid metabolism in 1990 and its description as one of the first examples for membrane contact sites at the turn of the century, the past decade has seen the emergence of this structure as a potential regulator of cancer growth and metabolism. The mechanistic basis for this hypothesis is that the MAM accommodates flux of Ca2+ from the endoplasmic reticulum (ER) to mitochondria. This flux then determines mitochondrial ATP production, known to be low in many tumors as part of the Warburg effect. However, low mitochondrial Ca2+ flux also reduces the propensity of tumor cells to undergo apoptosis, another cancer hallmark. Numerous regulators of this flux have been recently identified as MAM proteins. Not surprisingly, many fall into the groups of tumor suppressors and oncogenes. Given the important role that the MAM could play in cancer, it is expected that proteins mediating its formation are particularly implicated in tumorigenesis. Examples for such proteins are mitofusin-2 and phosphofurin acidic cluster sorting protein 2 that likely act as tumor suppressors. This review discusses how these proteins that mediate or regulate ER–mitochondria tethering are (or are not) promoting or inhibiting tumorigenesis. The emerging picture of MAMs in cancer seems to indicate that in addition to the downregulation of mitochondrial Ca2+ import, MAM defects are but one way how cancer cells control mitochondria metabolism and apoptosis. PMID:28603693

  2. Endoplasmic reticulum stress causes EBV lytic replication

    PubMed Central

    Taylor, Gwen Marie; Raghuwanshi, Sandeep K.; Rowe, David T.; Wadowsky, Robert M.

    2011-01-01

    Endoplasmic reticulum (ER) stress triggers a homeostatic cellular response in mammalian cells to ensure efficient folding, sorting, and processing of client proteins. In lytic-permissive lymphoblastoid cell lines (LCLs), pulse exposure to the chemical ER-stress inducer thapsigargin (TG) followed by recovery resulted in the activation of the EBV immediate-early (BRLF1, BZLF1), early (BMRF1), and late (gp350) genes, gp350 surface expression, and virus release. The protein phosphatase 1 a (PP1a)–specific phosphatase inhibitor Salubrinal (SAL) synergized with TG to induce EBV lytic genes; however, TG treatment alone was sufficient to activate EBV lytic replication. SAL showed ER-stress–dependent and –independent antiviral effects, preventing virus release in human LCLs and abrogating gp350 expression in 12-O-tetradecanoylphorbol-13-acetate (TPA)–treated B95-8 cells. TG resulted in sustained BCL6 but not BLIMP1 or CD138 expression, which is consistent with maintenance of a germinal center B-cell, rather than plasma-cell, phenotype. Microarray analysis identified candidate genes governing lytic replication in LCLs undergoing ER stress. PMID:21849482

  3. Endoplasmic reticulum stress effector CCAAT/enhancer-binding protein homologous protein (CHOP) regulates chronic kidney disease-induced vascular calcification.

    PubMed

    Miyazaki-Anzai, Shinobu; Masuda, Masashi; Demos-Davies, Kimberly M; Keenan, Audrey L; Saunders, Sommer J; Masuda, Rumiko; Jablonski, Kristen; Cavasin, Maria A; Kendrick, Jessica; Chonchol, Michel; McKinsey, Timothy A; Levi, Moshe; Miyazaki, Makoto

    2014-06-24

    Cardiovascular diseases such as atherosclerosis and vascular calcification are a major cause of death in patients with chronic kidney disease (CKD). Recently, the long-awaited results of the Study of Heart and Renal Protection trial were reported. This large randomized clinical trial found that an extensive cholesterol-lowering therapy through the combination of simvastatin and ezetimibe significantly reduced cardiovascular diseases in a wide range of patients with CKD. However, the mechanism by which this cholesterol-lowering therapy reduces CKD-dependent vascular diseases remains elusive. The objective of the present study was to determine the contribution of the oxysterol-induced pro-apoptotic transcription factor CCAAT/enhancer-binding protein homologous protein (CHOP) on the pathogenesis of CKD-dependent cardiovascular diseases through endoplasmic reticulum stress signaling. CKD increased levels of serum oxysterols such as 7-ketocholesterol in human patients and ApoE(-/-) mice. Treatment with simvastatin plus ezetimibe strongly reduced levels of serum oxysterols and attenuated CKD-dependent atherosclerosis, vascular cell death, vascular calcification, and cardiac dysfunction. This therapy also reduced aortic endoplasmic reticulum stress induced by CKD. The short hairpin RNA-mediated knockdown of CHOP and activating transcription factor-4 in vascular smooth muscle cells attenuated oxysterol-induced mineralization, osteogenic differentiation, and endoplasmic reticulum stress. In addition, CHOP deficiency protected ApoE(-/-) mice from CKD-dependent vascular calcification, cardiac dysfunction, and vascular cell death. These data reveal that the cholesterol-lowering therapy of simvastatin plus ezetimibe attenuates CKD-dependent vascular diseases through a reduction of oxysterol-mediated endoplasmic reticulum stress. CHOP plays a crucial role in the pathogenesis of CKD-dependent vascular calcification. © 2014 The Authors. Published on behalf of the American Heart

  4. Smooth eigenvalue correction

    NASA Astrophysics Data System (ADS)

    Hendrikse, Anne; Veldhuis, Raymond; Spreeuwers, Luuk

    2013-12-01

    Second-order statistics play an important role in data modeling. Nowadays, there is a tendency toward measuring more signals with higher resolution (e.g., high-resolution video), causing a rapid increase of dimensionality of the measured samples, while the number of samples remains more or less the same. As a result the eigenvalue estimates are significantly biased as described by the Marčenko Pastur equation for the limit of both the number of samples and their dimensionality going to infinity. By introducing a smoothness factor, we show that the Marčenko Pastur equation can be used in practical situations where both the number of samples and their dimensionality remain finite. Based on this result we derive methods, one already known and one new to our knowledge, to estimate the sample eigenvalues when the population eigenvalues are known. However, usually the sample eigenvalues are known and the population eigenvalues are required. We therefore applied one of the these methods in a feedback loop, resulting in an eigenvalue bias correction method. We compare this eigenvalue correction method with the state-of-the-art methods and show that our method outperforms other methods particularly in real-life situations often encountered in biometrics: underdetermined configurations, high-dimensional configurations, and configurations where the eigenvalues are exponentially distributed.

  5. Astrophysical smooth particle hydrodynamics

    NASA Astrophysics Data System (ADS)

    Rosswog, Stephan

    2009-04-01

    The paper presents a detailed review of the smooth particle hydrodynamics (SPH) method with particular focus on its astrophysical applications. We start by introducing the basic ideas and concepts and thereby outline all ingredients that are necessary for a practical implementation of the method in a working SPH code. Much of SPH's success relies on its excellent conservation properties and therefore the numerical conservation of physical invariants receives much attention throughout this review. The self-consistent derivation of the SPH equations from the Lagrangian of an ideal fluid is the common theme of the remainder of the text. We derive a modern, Newtonian SPH formulation from the Lagrangian of an ideal fluid. It accounts for changes of the local resolution lengths which result in corrective, so-called "grad-h-terms". We extend this strategy to special relativity for which we derive the corresponding grad-h equation set. The variational approach is further applied to a general-relativistic fluid evolving in a fixed, curved background space-time. Particular care is taken to explicitly derive all relevant equations in a coherent way.

  6. New smooth hybrid inflation

    SciTech Connect

    Lazarides, George; Vamvasakis, Achilleas

    2007-10-15

    We consider the extension of the supersymmetric Pati-Salam model which solves the b-quark mass problem of supersymmetric grand unified models with exact Yukawa unification and universal boundary conditions and leads to the so-called new shifted hybrid inflationary scenario. We show that this model can also lead to a new version of smooth hybrid inflation based only on renormalizable interactions provided that a particular parameter of its superpotential is somewhat small. The potential possesses valleys of minima with classical inclination, which can be used as inflationary paths. The model is consistent with the fitting of the three-year Wilkinson microwave anisotropy probe data by the standard power-law cosmological model with cold dark matter and a cosmological constant. In particular, the spectral index turns out to be adequately small so that it is compatible with the data. Moreover, the Pati-Salam gauge group is broken to the standard model gauge group during inflation and, thus, no monopoles are formed at the end of inflation. Supergravity corrections based on a nonminimal Kaehler potential with a convenient choice of a sign keep the spectral index comfortably within the allowed range without generating maxima and minima of the potential on the inflationary path. So, unnatural restrictions on the initial conditions for inflation can be avoided.

  7. Ceramic coatings on smooth surfaces

    NASA Technical Reports Server (NTRS)

    Miller, R. A. (Inventor); Brindley, W. J. (Inventor); Rouge, C. J. (Inventor)

    1991-01-01

    A metallic coating is plasma sprayed onto a smooth surface of a metal alloy substitute or on a bond coating. An initial thin ceramic layer is low pressure sprayed onto the smooth surface of the substrate or bond coating. Another ceramic layer is atmospheric plasma sprayed onto the initial ceramic layer.

  8. Ryanodine receptors in smooth muscle.

    PubMed

    Guerrero-Hernández, Agustín; Gómez-Viquez, Leticia; Guerrero-Serna, Guadalupe; Rueda, Angélica

    2002-07-01

    The sarcoplasmic reticulum (SR) of smooth muscle is endowed with two different types of Ca2+ release channels, i.e. inositol 1,4,5-trisphosphate receptors (IP3Rs) and ryanodine receptors (RyRs). In general, both release channels mobilize Ca2+ from the same internal store in smooth muscle. While the importance of IP3Rs in agonist-induced contraction is well established, the role of RyRs in excitation-contraction coupling of smooth muscle is not clear. The participation of smooth muscle RyRs in the amplification of Ca2+ transients induced by either opening of Ca2+-permeable channels or IP3-triggered Ca2+ release has been studied. The efficacy of both processes to activate RyRs by calcium-induced calcium release (CICR) is highly variable and not widely present in smooth muscle. Although RyRs in smooth muscle generate Ca2+ sparks that are similar to those observed in striated muscles, the contribution of these local Ca2+ events to depolarization-induced global rise in [Ca2+]i is rather limited. Recent data suggest that RyRs are involved in regulating the luminal [Ca2+] of SR and also in smooth muscle relaxation. This review summarizes studies that were carried out mainly in muscle strips or in freshly isolated myocytes, and that were aimed to determine the physiological role of RyRs in smooth muscle.

  9. Conservative smoothing versus artificial viscosity

    SciTech Connect

    Guenther, C.; Hicks, D.L.; Swegle, J.W.

    1994-08-01

    This report was stimulated by some recent investigations of S.P.H. (Smoothed Particle Hydrodynamics method). Solid dynamics computations with S.P.H. show symptoms of instabilities which are not eliminated by artificial viscosities. Both analysis and experiment indicate that conservative smoothing eliminates the instabilities in S.P.H. computations which artificial viscosities cannot. Questions were raised as to whether conservative smoothing might smear solutions more than artificial viscosity. Conservative smoothing, properly used, can produce more accurate solutions than the von Neumann-Richtmyer-Landshoff artificial viscosity which has been the standard for many years. The authors illustrate this using the vNR scheme on a test problem with known exact solution involving a shock collision in an ideal gas. They show that the norms of the errors with conservative smoothing are significantly smaller than the norms of the errors with artificial viscosity.

  10. Calcium Sensitization Mechanisms in Gastrointestinal Smooth Muscles.

    PubMed

    Perrino, Brian A

    2016-04-30

    An increase in intracellular Ca(2+) is the primary trigger of contraction of gastrointestinal (GI) smooth muscles. However, increasing the Ca(2+) sensitivity of the myofilaments by elevating myosin light chain phosphorylation also plays an essential role. Inhibiting myosin light chain phosphatase activity with protein kinase C-potentiated phosphatase inhibitor protein-17 kDa (CPI-17) and myosin phosphatase targeting subunit 1 (MYPT1) phosphorylation is considered to be the primary mechanism underlying myofilament Ca(2+) sensitization. The relative importance of Ca(2+) sensitization mechanisms to the diverse patterns of GI motility is likely related to the varied functional roles of GI smooth muscles. Increases in CPI-17 and MYPT1 phosphorylation in response to agonist stimulation regulate myosin light chain phosphatase activity in phasic, tonic, and sphincteric GI smooth muscles. Recent evidence suggests that MYPT1 phosphorylation may also contribute to force generation by reorganization of the actin cytoskeleton. The mechanisms responsible for maintaining constitutive CPI-17 and MYPT1 phosphorylation in GI smooth muscles are still largely unknown. The characteristics of the cell-types comprising the neuroeffector junction lead to fundamental differences between the effects of exogenous agonists and endogenous neurotransmitters on Ca(2+) sensitization mechanisms. The contribution of various cell-types within the tunica muscularis to the motor responses of GI organs to neurotransmission must be considered when determining the mechanisms by which Ca(2+) sensitization pathways are activated. The signaling pathways regulating Ca(2+) sensitization may provide novel therapeutic strategies for controlling GI motility. This article will provide an overview of the current understanding of the biochemical basis for the regulation of Ca(2+) sensitization, while also discussing the functional importance to different smooth muscles of the GI tract.

  11. Calcium Sensitization Mechanisms in Gastrointestinal Smooth Muscles

    PubMed Central

    Perrino, Brian A

    2016-01-01

    An increase in intracellular Ca2+ is the primary trigger of contraction of gastrointestinal (GI) smooth muscles. However, increasing the Ca2+ sensitivity of the myofilaments by elevating myosin light chain phosphorylation also plays an essential role. Inhibiting myosin light chain phosphatase activity with protein kinase C-potentiated phosphatase inhibitor protein-17 kDa (CPI-17) and myosin phosphatase targeting subunit 1 (MYPT1) phosphorylation is considered to be the primary mechanism underlying myofilament Ca2+ sensitization. The relative importance of Ca2+ sensitization mechanisms to the diverse patterns of GI motility is likely related to the varied functional roles of GI smooth muscles. Increases in CPI-17 and MYPT1 phosphorylation in response to agonist stimulation regulate myosin light chain phosphatase activity in phasic, tonic, and sphincteric GI smooth muscles. Recent evidence suggests that MYPT1 phosphorylation may also contribute to force generation by reorganization of the actin cytoskeleton. The mechanisms responsible for maintaining constitutive CPI-17 and MYPT1 phosphorylation in GI smooth muscles are still largely unknown. The characteristics of the cell-types comprising the neuroeffector junction lead to fundamental differences between the effects of exogenous agonists and endogenous neurotransmitters on Ca2+ sensitization mechanisms. The contribution of various cell-types within the tunica muscularis to the motor responses of GI organs to neurotransmission must be considered when determining the mechanisms by which Ca2+ sensitization pathways are activated. The signaling pathways regulating Ca2+ sensitization may provide novel therapeutic strategies for controlling GI motility. This article will provide an overview of the current understanding of the biochemical basis for the regulation of Ca2+ sensitization, while also discussing the functional importance to different smooth muscles of the GI tract. PMID:26701920

  12. Regeneration and Maintenance of Intestinal Smooth Muscle Phenotypes

    NASA Astrophysics Data System (ADS)

    Walthers, Christopher M.

    Tissue engineering is an emerging field of biomedical engineering that involves growing artificial organs to replace those lost to disease or injury. Within tissue engineering, there is a demand for artificial smooth muscle to repair tissues of the digestive tract, bladder, and vascular systems. Attempts to develop engineered smooth muscle tissues capable of contracting with sufficient strength to be clinically relevant have so far proven unsatisfactory. The goal of this research was to develop and sustain mature, contractile smooth muscle. Survival of implanted SMCs is critical to sustain the benefits of engineered smooth muscle. Survival of implanted smooth muscle cells was studied with layered, electrospun polycaprolactone implants with lasercut holes ranging from 0--25% porosity. It was found that greater angiogenesis was associated with increased survival of implanted cells, with a large increase at a threshold between 20% and 25% porosity. Heparan sulfate coatings improved the speed of blood vessel infiltration after 14 days of implantation. With these considerations, thicker engineered tissues may be possible. An improved smooth muscle tissue culture technique was utilized. Contracting smooth muscle was produced in culture by maintaining the native smooth muscle tissue organization, specifically by sustaining intact smooth muscle strips rather than dissociating tissue in to isolated smooth muscle cells. Isolated cells showed a decrease in maturity and contained fewer enteric neural and glial cells. Muscle strips also exhibited periodic contraction and regular fluctuation of intracellular calclium. The muscle strip maturity persisted after implantation in omentum for 14 days on polycaprolactone scaffolds. A low-cost, disposable bioreactor was developed to further improve maturity of cultured smooth muscle cells in an environment of controlled cyclical stress.The bioreactor consistently applied repeated mechanical strain with controllable inputs for strain

  13. Endoplasmic reticulum stress implicated in chronic traumatic encephalopathy.

    PubMed

    Lucke-Wold, Brandon P; Turner, Ryan C; Logsdon, Aric F; Nguyen, Linda; Bailes, Julian E; Lee, John M; Robson, Matthew J; Omalu, Bennet I; Huber, Jason D; Rosen, Charles L

    2016-03-01

    Chronic traumatic encephalopathy is a progressive neurodegenerative disease characterized by neurofibrillary tau tangles following repetitive neurotrauma. The underlying mechanism linking traumatic brain injury to chronic traumatic encephalopathy has not been elucidated. The authors investigate the role of endoplasmic reticulum stress as a link between acute neurotrauma and chronic neurodegeneration. The authors used pharmacological, biochemical, and behavioral tools to assess the role of endoplasmic reticulum stress in linking acute repetitive traumatic brain injury to the development of chronic neurodegeneration. Data from the authors' clinically relevant and validated rodent blast model were compared with those obtained from postmortem human chronic traumatic encephalopathy specimens from a National Football League player and World Wrestling Entertainment wrestler. The results demonstrated strong correlation of endoplasmic reticulum stress activation with subsequent tau hyperphosphorylation. Various endoplasmic reticulum stress markers were increased in human chronic traumatic encephalopathy specimens, and the endoplasmic reticulum stress response was associated with an increase in the tau kinase, glycogen synthase kinase-3β. Docosahexaenoic acid, an endoplasmic reticulum stress inhibitor, improved cognitive performance in the rat model 3 weeks after repetitive blast exposure. The data showed that docosahexaenoic acid administration substantially reduced tau hyperphosphorylation (t = 4.111, p < 0.05), improved cognition (t = 6.532, p < 0.001), and inhibited C/EBP homology protein activation (t = 5.631, p < 0.01). Additionally the data showed, for the first time, that endoplasmic reticulum stress is involved in the pathophysiology of chronic traumatic encephalopathy. Docosahexaenoic acid therefore warrants further investigation as a potential therapeutic agent for the prevention of chronic traumatic encephalopathy.

  14. Smooth and Scrambled

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 19 June 2003

    A flat-floored crater in central Arabia hosts an interior crater with interesting ejecta. The scrambled patterns in the ejecta suggest fluidized flow during emplacement. This contrasts with the much smoother terrain on the left side of the image. Although there is some ambiguity, it appears that the smooth material has lapped up onto the ejecta, which raises the question of where the source is for this more recent flow of material.

    Image information: VIS instrument. Latitude 2.8, Longitude 37 East (323 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  15. The PI-PLC inhibitor U-73122 is a potent inhibitor of the SERCA pump in smooth muscle.

    PubMed

    Hollywood, M A; Sergeant, G P; Thornbury, K D; McHale, N G

    2010-07-01

    In this issue MacMillan and McCarron in 2010 demonstrated that the phospholipase C (PLC) inhibitor U-73122 can potently inhibit Ca(2+) release from isolated smooth muscle cells independent of its effect on PLC. Their data suggest that the PLC inhibitor can block the sarcoplasmic/endoplasmic reticulum calcium ATPase pump in smooth muscle and cast doubt on the reliability of U-73122 as the main pharmacological tool to assess the role of the phosphotidyl inositol-PLC pathway in cellular signalling.

  16. 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.

  17. 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.

  18. Smooth Compliant Antifoulant Coatings.

    DTIC Science & Technology

    1982-09-30

    mercury * Organic arsenic compounds such as oxybisphenoxarsine e Variations on the tri-organo tin salts * Napthenic acids and their heavy metal salts...potential. Likewise, the new azelaic anhydride shows promise as an alter- native blend in the three-dimensional composites. The acoustic behavior of these

  19. Altered Endoplasmic Reticulum Calcium Pump Expression during Breast Tumorigenesis

    PubMed Central

    Papp, Béla; Brouland, Jean-Philippe

    2011-01-01

    Endoplasmic reticulum calcium homeostasis is involved in several essential cell functions including cell proliferation, protein synthesis, stress responses or secretion. Calcium uptake into the endoplasmic reticulum is performed by Sarco/Endoplasmic Reticulum Calcium ATPases (SERCA enzymes). In order to study endoplasmic reticulum calcium homeostasis in situ in mammary tissue, in this work SERCA3 expression was investigated in normal breast and in its benign and malignant lesions in function of the cell type, degree of malignancy, and histological and molecular parameters of the tumors. Our data indicate, that although normal breast acinar epithelial cells express SERCA3 abundantly, its expression is strongly decreased already in very early non-malignant epithelial lesions such as adenosis, and remains low in lobular carcinomas. Whereas normal duct epithelium expresses significant amounts of SERCA3, its expression is decreased in several benign ductal lesions, as well as in ductal adenocarcinoma. The loss of SERCA3 expression is correlated with Elston-Ellis grade, negative hormone receptor expression or triple negative status in ductal carcinomas. The concordance between decreased SERCA3 expression and several histological, as well as molecular markers of ductal carcinogenesis indicates that endoplasmic reticulum calcium homeostasis is remodeled during tumorigenesis in the breast epithelium. PMID:21863130

  20. Embedding smooth diffeomorphisms in flows

    NASA Astrophysics Data System (ADS)

    Zhang, Xiang

    In this paper we study the problem on embedding germs of smooth diffeomorphisms in flows in higher dimensional spaces. First we prove the existence of embedding vector fields for a local diffeomorphism with its nonlinear term a resonant polynomial. Then using this result and the normal form theory, we obtain a class of local C diffeomorphisms for k∈N∪{∞,ω} which admit embedding vector fields with some smoothness. Finally we prove that for any k∈N∪{∞} under the coefficient topology the subset of local C diffeomorphisms having an embedding vector field with some smoothness is dense in the set of all local C diffeomorphisms.

  1. Simple Robust Fixed Lag Smoothing

    DTIC Science & Technology

    1988-12-02

    SIMPLE ROBUST FIXED LAG SMOOTHING by ~N. D. Le R.D. Martin 4 TECHNICAL RlEPORT No. 149 December 1988 Department of Statistics, GN-22 Accesion For...frLsD1ist Special A- Z Simple Robust Fixed Lag Smoothing With Application To Radar Glint Noise * N. D. Le R. D. Martin Department of Statistics, GN...smoothers. The emphasis here is on fixed-lag smoothing , as opposed to the use of existing robust fixed interval smoothers (e.g., as in Martin, 1979

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

    PubMed Central

    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

  3. 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.

  4. Young Craters on Smooth Plains

    NASA Image and Video Library

    2000-01-15

    This image, from NASA Mariner 10 spacecraft which launched in 1974, shows young craters superposed on smooth plains. Larger young craters have central peaks, flat floors, terraced walls, and radial ejecta deposits.

  5. Impact Crater with Smoothed Rim

    NASA Image and Video Library

    2012-03-01

    This image from NASA Dawn spacecraft of asteroid Vesta shows hows a large impact crater whose rim is rather smoothed and degraded. There are many smaller, younger craters surrounding and inside of this crater and these have sharper, fresher rims.

  6. 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.

  7. Smooth electrode and method of fabricating same

    SciTech Connect

    Weaver, Stanton Earl; Kennerly, Stacey Joy; Aimi, Marco Francesco

    2012-08-14

    A smooth electrode is provided. The smooth electrode includes at least one metal layer having thickness greater than about 1 micron; wherein an average surface roughness of the smooth electrode is less than about 10 nm.

  8. 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.

  9. Lipid Transport between the Endoplasmic Reticulum and Mitochondria

    PubMed Central

    Flis, Vid V.

    2013-01-01

    Mitochondria are partially autonomous organelles that depend on the import of certain proteins and lipids to maintain cell survival and membrane formation. Although phosphatidylglycerol, cardiolipin, and phosphatidylethanolamine are synthesized by mitochondrial enzymes, phosphatidylcholine, phosphatidylinositol, phosphatidylserine, and sterols need to be imported from other organelles. The origin of most lipids imported into mitochondria is the endoplasmic reticulum, which requires interaction of these two subcellular compartments. Recently, protein complexes that are involved in membrane contact between endoplasmic reticulum and mitochondria were identified, but their role in lipid transport is still unclear. In the present review, we describe components involved in lipid translocation between the endoplasmic reticulum and mitochondria and discuss functional as well as regulatory aspects that are important for lipid homeostasis. PMID:23732475

  10. Radar data smoothing filter study

    NASA Technical Reports Server (NTRS)

    White, J. V.

    1984-01-01

    The accuracy of the current Wallops Flight Facility (WFF) data smoothing techniques for a variety of radars and payloads is examined. Alternative data reduction techniques are given and recommendations are made for improving radar data processing at WFF. A data adaptive algorithm, based on Kalman filtering and smoothing techniques, is also developed for estimating payload trajectories above the atmosphere from noisy time varying radar data. This algorithm is tested and verified using radar tracking data from WFF.

  11. Active controls for ride smoothing

    NASA Technical Reports Server (NTRS)

    Conner, D. W.; Thompson, G. O.

    1976-01-01

    Active controls technology offers great promise for significantly smoothing the ride, and thus improving public and air carrier acceptance, of certain types of transport aircraft. Recent findings which support this promise are presented in the following three pertinent areas: (1) Ride quality versus degree of traveler satisfaction; (2) significant findings from a feasibility study of a ride smoothing system; and (3) potential ride problems identified for several advanced transport concepts.

  12. Endoplasmic reticulum stress is involved in apoptosis of detrusor muscle in streptozocin-induced diabetic rats.

    PubMed

    Wang, Dongwen; Yuan, Xiaobin; Hu, Caoyang; Zhang, Bin; Gao, Hongfei; Wang, Dong; Chi, Junjie; Jing, Qiang; Wu, Shulin; Wu, Chin-Lee

    2017-01-01

    Endoplasmic reticulum stress (ERS) has been proven to be associated with apoptosis and plays a critical role in the development of many diabetic complications. In the pathogenesis of diabetic cystopathy (DCP), the role of ERS is still unclear. Our study is aimed at the investigation of the involvement of ERS-associated detrusor muscle apoptosis in streptozocin (STZ)-induced diabetic rats. At different timepoints (4, 8, 12, and 16 weeks after induction of type 1 diabetic rat models), hematoxylin & eosin (H&E) staining was performed to assess the histological changes of the diabetic detrusor; the sub-cellular ultrastructure, especially the zone of endoplasmic reticulum (ER), was observed by transmission electron microscopy (TEM), and the terminal deoxynucleotidyl transferase-mediated DNA nick-end labeling (TUNEL) staining was used to identify the enhanced apoptosis. Moreover, the expression of three hallmarks of ERS-associated apoptosis, including glucose-regulated protein 78 (GRP78), CCAAT/enhancer-binding protein homologous protein (CHOP), and caspase12, was detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. Light microscopic impairments of histology, including progressive loosely packed muscle bundles and increased fibrous tissue, can be seen; the ultrastructural changes featuring the swollen and fused cisternaes in ER zone and deformed nucleus were also observed in the detrusor smooth muscle (DSM). Increased apoptosis and elevated expression of GRP78, CHOP, and caspase12 at both protein and mRNA levels in a time-dependent fashion were detected. The occurrence of ERS-associated apoptosis may be involved in the development of DCP and may contribute to the diabetic detrusor impairment. Neurourol. Urodynam. 36:65-72, 2017. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  13. Smooth Tubercle Bacilli: Neglected Opportunistic Tropical Pathogens

    PubMed Central

    Aboubaker Osman, Djaltou; Bouzid, Feriel; Canaan, Stéphane; Drancourt, Michel

    2016-01-01

    Smooth tubercle bacilli (STB) including “Mycobacterium canettii” are members of the Mycobacterium tuberculosis complex (MTBC), which cause non-contagious tuberculosis in human. This group comprises <100 isolates characterized by smooth colonies and cordless organisms. Most STB isolates have been obtained from patients exposed to the Republic of Djibouti but seven isolates, including the three seminal ones obtained by Georges Canetti between 1968 and 1970, were recovered from patients in France, Madagascar, Sub-Sahara East Africa, and French Polynesia. STB form a genetically heterogeneous group of MTBC organisms with large 4.48 ± 0.05 Mb genomes, which may link Mycobacterium kansasii to MTBC organisms. Lack of inter-human transmission suggested a yet unknown environmental reservoir. Clinical data indicate a respiratory tract route of contamination and the digestive tract as an alternative route of contamination. Further epidemiological and clinical studies are warranted to elucidate areas of uncertainty regarding these unusual mycobacteria and the tuberculosis they cause. PMID:26793699

  14. Temperature-sensitive, Post-translational Regulation of Plant Omega-3 Fatty-acid Desaturases is Mediated by the Endoplasmic Reticulum-associated Degradation Pathway

    USDA-ARS?s Scientific Manuscript database

    Changes in ambient temperature represent a major physiological challenge to poikilothermic organisms that requires rapid adjustments in the composition of cellular membranes in order to preserve overall membrane dynamics and integrity. In plants, the endoplasmic reticulum-localized omega-3 fatty ac...

  15. Continuous network of endoplasmic reticulum in cerebellar Purkinje neurons.

    PubMed Central

    Terasaki, M; Slater, N T; Fein, A; Schmidek, A; Reese, T S

    1994-01-01

    Purkinje neurons in rat cerebellar slices injected with an oil drop saturated with 1,1'-dihexadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate [DiIC16(3) or DiI] to label the endoplasmic reticulum were observed by confocal microscopy. DiI spread throughout the cell body and dendrites and into the axon. DiI spreading is due to diffusion in a continuous bilayer and is not due to membrane trafficking because it also spreads in fixed neurons. DiI stained such features of the endoplasmic reticulum as densities at branch points, reticular networks in the cell body and dendrites, nuclear envelope, spines, and aggregates formed during anoxia nuclear envelope, spines, and aggregates formed during anoxia in low extracellular Ca2+. In cultured rat hippocampal neurons, where optical conditions provide more detail, DiI labeled a clearly delineated network of endoplasmic reticulum in the cell body. We conclude that there is a continuous compartment of endoplasmic reticulum extending from the cell body throughout the dendrites. This compartment may coordinate and integrate neuronal functions. Images PMID:7519781

  16. 7 CFR 51.1159 - Smooth texture.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Smooth texture. 51.1159 Section 51.1159 Agriculture... Standards for Grades of Florida Oranges and Tangelos Definitions § 51.1159 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size of the fruit. ...

  17. 7 CFR 51.1159 - Smooth texture.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Smooth texture. 51.1159 Section 51.1159 Agriculture... Standards for Grades of Florida Oranges and Tangelos Definitions § 51.1159 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size of the fruit. ...

  18. 7 CFR 51.698 - Smooth texture.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Smooth texture. 51.698 Section 51.698 Agriculture..., California, and Arizona) Definitions § 51.698 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size of the fruit. ...

  19. 7 CFR 51.1159 - Smooth texture.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Smooth texture. 51.1159 Section 51.1159 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... § 51.1159 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and...

  20. 7 CFR 51.636 - Smooth texture.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Smooth texture. 51.636 Section 51.636 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing...) Definitions § 51.636 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and...

  1. 7 CFR 51.768 - Smooth texture.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Smooth texture. 51.768 Section 51.768 Agriculture... Standards for Grades of Florida Grapefruit Definitions § 51.768 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size of the fruit. “Thin” means that the skin...

  2. 7 CFR 51.1159 - Smooth texture.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Smooth texture. 51.1159 Section 51.1159 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... § 51.1159 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and...

  3. 7 CFR 51.768 - Smooth texture.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Smooth texture. 51.768 Section 51.768 Agriculture... Standards for Grades of Florida Grapefruit Definitions § 51.768 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size of the fruit. “Thin” means that the skin...

  4. 7 CFR 51.636 - Smooth texture.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Smooth texture. 51.636 Section 51.636 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing...) Definitions § 51.636 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and...

  5. 7 CFR 51.1159 - Smooth texture.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Smooth texture. 51.1159 Section 51.1159 Agriculture... Standards for Grades of Florida Oranges and Tangelos Definitions § 51.1159 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size of the fruit. ...

  6. 7 CFR 51.636 - Smooth texture.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Smooth texture. 51.636 Section 51.636 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing...) Definitions § 51.636 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and...

  7. 7 CFR 51.768 - Smooth texture.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Smooth texture. 51.768 Section 51.768 Agriculture... Standards for Grades of Florida Grapefruit Definitions § 51.768 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size of the fruit. “Thin” means that the skin...

  8. 7 CFR 51.636 - Smooth texture.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Smooth texture. 51.636 Section 51.636 Agriculture... Florida, California, and Arizona) Definitions § 51.636 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size of the fruit. ...

  9. 7 CFR 51.698 - Smooth texture.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Smooth texture. 51.698 Section 51.698 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... § 51.698 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size...

  10. 7 CFR 51.698 - Smooth texture.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Smooth texture. 51.698 Section 51.698 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... § 51.698 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size...

  11. 7 CFR 51.698 - Smooth texture.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Smooth texture. 51.698 Section 51.698 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... § 51.698 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size...

  12. 7 CFR 51.636 - Smooth texture.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Smooth texture. 51.636 Section 51.636 Agriculture... Florida, California, and Arizona) Definitions § 51.636 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size of the fruit. ...

  13. 7 CFR 51.698 - Smooth texture.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Smooth texture. 51.698 Section 51.698 Agriculture..., California, and Arizona) Definitions § 51.698 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size of the fruit. ...

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

    PubMed Central

    1983-01-01

    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

  15. Sulfatase modifying factor 1 trafficking through the cells: from endoplasmic reticulum to the endoplasmic reticulum.

    PubMed

    Zito, Ester; Buono, Mario; Pepe, Stefano; Settembre, Carmine; Annunziata, Ida; Surace, Enrico Maria; Dierks, Thomas; Monti, Maria; Cozzolino, Marianna; Pucci, Piero; Ballabio, Andrea; Cosma, Maria Pia

    2007-05-16

    Sulfatase modifying factor 1 (SUMF1) is the gene mutated in multiple sulfatase deficiency (MSD) that encodes the formylglycine-generating enzyme, an essential activator of all the sulfatases. SUMF1 is a glycosylated enzyme that is resident in the endoplasmic reticulum (ER), although it is also secreted. Here, we demonstrate that upon secretion, SUMF1 can be taken up from the medium by several cell lines. Furthermore, the in vivo engineering of mice liver to produce SUMF1 shows its secretion into the blood serum and its uptake into different tissues. Additionally, we show that non-glycosylated forms of SUMF1 can still be secreted, while only the glycosylated SUMF1 enters cells, via a receptor-mediated mechanism. Surprisingly, following its uptake, SUMF1 shuttles from the plasma membrane to the ER, a route that has to date only been well characterized for some of the toxins. Remarkably, once taken up and relocalized into the ER, SUMF1 is still active, enhancing the sulfatase activities in both cultured cells and mice tissues.

  16. Income Smoothing: Methodology and Models.

    DTIC Science & Technology

    1986-05-01

    that managers desire a pattern % of income that has low variability relative to a linear time trend. 2. Industry Trend. Target 2 assumes that firms...R167 55? INCOME SMOOTHING: METHODOLOGY ND NODELS(U) UMVL in1POSTGRADUATE SCHOOL MONTEREY CA 0 D HOSES "AY S6 UNCLASSIFIED NP5-604FO53 E * I* vu...California oCiD ELEC fl MAY 12 986 INCOME SMOOTHING - METHODOLOGY AND MODELS by 0. Douglas Moses May 1986 *Approved frpublic release; ditibto uniie

  17. Se Enhances MLCK Activation by Regulating Selenoprotein T (SelT) in the Gastric Smooth Muscle of Rats.

    PubMed

    Li, Jia-Ping; Zhou, Jing-Xuan; Wang, Qi; Gu, Gao-Qin; Yang, Shi-Jin; Li, Cheng-Ye; Qiu, Chang-Wei; Deng, Gan-Zhen; Guo, Meng-Yao

    2016-09-01

    Selenium (Se), a nutritionally essential trace element, is associated with health and disease. Selenoprotein T (SelT) was identified as a redoxin protein with a selenocystein, localizing in the endoplasmic reticulum. The myosin light chain kinase (MLCK) and myosin light chain (MLC) play key roles in the contraction process of smooth muscle. The present study was to detect the effect and mechanism of SelT on the contraction process of gastric smooth muscle. The WT rats were fed with different Se concentration diets, and Se and Ca(2+) concentrations were detected in the gastric smooth muscle. Western blot and qPCR were performed to determine SelT, CaM, MLCK, and MLC expressions. MLCK activity was measured by identifying the rates of [γ-32P]ATP incorporated into the MLC. The results showed Se and Ca(2+) concentrations were enhanced with Se intake in gastric smooth muscle tissues. With increasing Se, SelT, CaM, MLCK and MLC expressions increased, and MLCK and MLC activation improved in gastric smooth muscle tissue. The SelT RNA interference experiments showed that Ca(2+) release, MLCK activation, and MLC phosphorylation were regulated by SelT. Se affected the gastric smooth muscle constriction by regulating Ca(2+) release, MLCK activation, and MLC phosphorylation through SelT. Se plays a major role in regulating the contraction processes of gastric smooth muscle with the SelT.

  18. Protein disulfide isomerase-endoplasmic reticulum resident protein 57 regulates allergen-induced airways inflammation, fibrosis, and hyperresponsiveness.

    PubMed

    Hoffman, Sidra M; Chapman, David G; Lahue, Karolyn G; Cahoon, Jonathon M; Rattu, Gurkiranjit K; Daphtary, Nirav; Aliyeva, Minara; Fortner, Karen A; Erzurum, Serpil C; Comhair, Suzy A A; Woodruff, Prescott G; Bhakta, Nirav; Dixon, Anne E; Irvin, Charles G; Janssen-Heininger, Yvonne M W; Poynter, Matthew E; Anathy, Vikas

    2016-03-01

    Evidence for association between asthma and the unfolded protein response is emerging. Endoplasmic reticulum resident protein 57 (ERp57) is an endoplasmic reticulum-localized redox chaperone involved in folding and secretion of glycoproteins. We have previously demonstrated that ERp57 is upregulated in allergen-challenged human and murine lung epithelial cells. However, the role of ERp57 in asthma pathophysiology is unknown. Here we sought to examine the contribution of airway epithelium-specific ERp57 in the pathogenesis of allergic asthma. We examined the expression of ERp57 in human asthmatic airway epithelium and used murine models of allergic asthma to evaluate the relevance of epithelium-specific ERp57. Lung biopsy specimens from asthmatic and nonasthmatic patients revealed a predominant increase in ERp57 levels in epithelium of asthmatic patients. Deletion of ERp57 resulted in a significant decrease in inflammatory cell counts and airways resistance in a murine model of allergic asthma. Furthermore, we observed that disulfide bridges in eotaxin, epidermal growth factor, and periostin were also decreased in the lungs of house dust mite-challenged ERp57-deleted mice. Fibrotic markers, such as collagen and α smooth muscle actin, were also significantly decreased in the lungs of ERp57-deleted mice. Furthermore, adaptive immune responses were dispensable for house dust mite-induced endoplasmic reticulum stress and airways fibrosis. Here we show that ERp57 levels are increased in the airway epithelium of asthmatic patients and in mice with allergic airways disease. The ERp57 level increase is associated with redox modification of proinflammatory, apoptotic, and fibrotic mediators and contributes to airways hyperresponsiveness. The strategies to inhibit ERp57 specifically within the airways epithelium might provide an opportunity to alleviate the allergic asthma phenotype. Copyright © 2015 American Academy of Allergy, Asthma & Immunology. Published by Elsevier

  19. Caveolae in smooth muscles: nanocontacts

    PubMed Central

    Popescu, LM; Gherghiceanu, Mihaela; Mandache, E; Cretoiu, D

    2006-01-01

    Smooth muscle cell (SMC) caveolae have been investigated by quantitative and qualitative analysis of transmission electron microscopy (TEM) images of rat stomach, bladder and myometrium, guinea pig taenia coli, human ileum, and rat aortic SMCs. Ultrathin (below 30 nm) serial sections were used for examination of caveolar morphology and their connections with SMC organelles. Average caveolar diameter was smaller in vascular SMCs (70 nm, n=50) than in visceral SMCs (77 nm, n=100), but with the same morphology. Most of the caveolae, featured as flask-shaped plasma membrane (PM) invaginations, opened to the extracellular space through a 20 nm stoma (21, 3nm) having a 7 nm thick diaphragm. A small percentage of caveolae (3%), gathered as grape-like clusters, did not open directly to the extracellular space, but to irregular PM pockets having a 20-30 nm opening to the extracellular space. In visceral SMCs, caveolae were disposed in 4 - 6 rows, parallel to myofilaments, whilst aortic SMCs caveolae were arranged as clusters. This caveolar organization in rows or clusters minimizes the occupied volume, providing more space for the contractile machinery. The morphometric analysis of relative volumes (% of cell volume) showed that caveolae were more conspicuous in visceral than in vascular SMCs (myometrium - 2.40%; bladder - 3.66%, stomach - 2.61%, aorta - 1.43%). We also observed a higher number of caveolae per length unit of cell membrane in most visceral SMCs compared to vascular SMCs (myometrium - 1.06/μm, bladder - 0.74/μm, aorta - 0.57/μm, stomach - 0.48/μm). Caveolae increase the cellular perimeter up to 15% and enlarge the surface area of the plasma membrane about 80% in SMCs. Three-dimensional reconstructions (15μ3) showed that most caveolae, in both visceral and vascular SMCs, have nanocontacts with SR (87%), or with mitochondria (10%), and only 3%, apparently, have no contact with these organelles. Usually, 15 nm wide junctional spaces exist between caveolae

  20. Uncoupled redox systems in the lumen of the endoplasmic reticulum. Pyridine nucleotides stay reduced in an oxidative environment.

    PubMed

    Piccirella, Simona; Czegle, Ibolya; Lizák, Beáta; Margittai, Eva; Senesi, Silvia; Papp, Eszter; Csala, Miklós; Fulceri, Rosella; Csermely, Péter; Mandl, József; Benedetti, Angelo; Bánhegyi, Gábor

    2006-02-24

    The redox state of the intraluminal pyridine nucleotide pool was investigated in rat liver microsomal vesicles. The vesicles showed cortisone reductase activity in the absence of added reductants, which was dependent on the integrity of the membrane. The intraluminal pyridine nucleotide pool could be oxidized by the addition of cortisone or metyrapone but not of glutathione. On the other hand, intraluminal pyridine nucleotides were slightly reduced by cortisol or glucose 6-phosphate, although glutathione was completely ineffective. Redox state of microsomal protein thiols/disulfides was not altered either by manipulations affecting the redox state of pyridine nucleotides or by the addition of NAD(P)+ or NAD(P)H. The uncoupling of the thiol/disulfide and NAD(P)+/NAD(P)H redox couples was not because of their subcompartmentation, because enzymes responsible for the intraluminal oxidoreduction of pyridine nucleotides were distributed equally in smooth and rough microsomal subfractions. Instead, the phenomenon can be explained by the negligible representation of glutathione reductase in the endoplasmic reticulum lumen. The results demonstrated the separate existence of two redox systems in the endoplasmic reticulum lumen, which explains the contemporary functioning of oxidative folding and of powerful reductive reactions.

  1. Registration of 'Newell' Smooth Bromegrass

    USDA-ARS?s Scientific Manuscript database

    ‘Newell’ (Reg. No. CV-xxxx, PI 671851) smooth bromegrass (Bromus inermis Leyss.) is a steppe or southern type cultivar that is primarily adapted in the USA to areas north of 40o N lat. and east of 100o W long. that have 500 mm or more annual precipitation or in areas that have similar climate cond...

  2. Regulation of gastrointestinal motility--insights from smooth muscle biology.

    PubMed

    Sanders, Kenton M; Koh, Sang Don; Ro, Seungil; Ward, Sean M

    2012-11-01

    Gastrointestinal motility results from coordinated contractions of the tunica muscularis, the muscular layers of the alimentary canal. Throughout most of the gastrointestinal tract, smooth muscles are organized into two layers of circularly or longitudinally oriented muscle bundles. Smooth muscle cells form electrical and mechanical junctions between cells that facilitate coordination of contractions. Excitation-contraction coupling occurs by Ca(2+) entry via ion channels in the plasma membrane, leading to a rise in intracellular Ca(2+). Ca(2+) binding to calmodulin activates myosin light chain kinase; subsequent phosphorylation of myosin initiates cross-bridge cycling. Myosin phosphatase dephosphorylates myosin to relax muscles, and a process known as Ca(2+) sensitization regulates the activity of the phosphatase. Gastrointestinal smooth muscles are 'autonomous' and generate spontaneous electrical activity (slow waves) that does not depend upon input from nerves. Intrinsic pacemaker activity comes from interstitial cells of Cajal, which are electrically coupled to smooth muscle cells. Patterns of contractile activity in gastrointestinal muscles are determined by inputs from enteric motor neurons that innervate smooth muscle cells and interstitial cells. Here we provide an overview of the cells and mechanisms that generate smooth muscle contractile behaviour and gastrointestinal motility.

  3. Regulation of gastrointestinal motility—insights from smooth muscle biology

    PubMed Central

    Sanders, Kenton M.; Koh, Sang Don; Ro, Seungil; Ward, Sean M.

    2014-01-01

    Gastrointestinal motility results from coordinated contractions of the tunica muscularis, the muscular layers of the alimentary canal. Throughout most of the gastrointestinal tract, smooth muscles are organized into two layers of circularly or longitudinally oriented muscle bundles. Smooth muscle cells form electrical and mechanical junctions between cells that facilitate coordination of contractions. Excitation–contraction coupling occurs by Ca2+ entry via ion channels in the plasma membrane, leading to a rise in intracellular Ca2+. Ca2+ binding to calmodulin activates myosin light chain kinase; subsequent phosphorylation of myosin initiates cross-bridge cycling. Myosin phosphatase dephosphorylates myosin to relax muscles, and a process known as Ca2+ sensitization regulates the activity of the phosphatase. Gastrointestinal smooth muscles are ‘autonomous’ and generate spontaneous electrical activity (slow waves) that does not depend upon input from nerves. Intrinsic pacemaker activity comes from interstitial cells of Cajal, which are electrically coupled to smooth muscle cells. Patterns of contractile activity in gastrointestinal muscles are determined by inputs from enteric motor neurons that innervate smooth muscle cells and interstitial cells. Here we provide an overview of the cells and mechanisms that generate smooth muscle contractile behaviour and gastrointestinal motility. PMID:22965426

  4. The Endoplasmic Reticulum Coat Protein II Transport Machinery Coordinates Cellular Lipid Secretion and Cholesterol Biosynthesis*

    PubMed Central

    Fryer, Lee G. D.; Jones, Bethan; Duncan, Emma J.; Hutchison, Claire E.; Ozkan, Tozen; Williams, Paul A.; Alder, Olivia; Nieuwdorp, Max; Townley, Anna K.; Mensenkamp, Arjen R.; Stephens, David J.; Dallinga-Thie, Geesje M.; Shoulders, Carol C.

    2014-01-01

    Triglycerides and cholesterol are essential for life in most organisms. Triglycerides serve as the principal energy storage depot and, where vascular systems exist, as a means of energy transport. Cholesterol is essential for the functional integrity of all cellular membrane systems. The endoplasmic reticulum is the site of secretory lipoprotein production and de novo cholesterol synthesis, yet little is known about how these activities are coordinated with each other or with the activity of the COPII machinery, which transports endoplasmic reticulum cargo to the Golgi. The Sar1B component of this machinery is mutated in chylomicron retention disorder, indicating that this Sar1 isoform secures delivery of dietary lipids into the circulation. However, it is not known why some patients with chylomicron retention disorder develop hepatic steatosis, despite impaired intestinal fat malabsorption, and why very severe hypocholesterolemia develops in this condition. Here, we show that Sar1B also promotes hepatic apolipoprotein (apo) B lipoprotein secretion and that this promoting activity is coordinated with the processes regulating apoB expression and the transfer of triglycerides/cholesterol moieties onto this large lipid transport protein. We also show that although Sar1A antagonizes the lipoprotein secretion-promoting activity of Sar1B, both isoforms modulate the expression of genes encoding cholesterol biosynthetic enzymes and the synthesis of cholesterol de novo. These results not only establish that Sar1B promotes the secretion of hepatic lipids but also adds regulation of cholesterol synthesis to Sar1B's repertoire of transport functions. PMID:24338480

  5. 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

  6. 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

  7. Role of Transient Receptor Potential Vanilloid 1 (TRPV1) in the Modulation of Airway Smooth Muscle Tone and Calcium Handling.

    PubMed

    Yocum, Gene T; Chen, Jun; Choi, Christine H; Townsend, Elizabeth A; Zhang, Yi; Xu, Dingbang; Fu, Xiao Wen; Sanderson, Michael J; Emala, Charles W

    2017-03-23

    Asthma is a common disorder characterized, in part, by airway smooth muscle (ASM) hyperresponsiveness. Transient receptor potential vanilloid 1 (TRPV1) is a non-selective cation channel expressed on airway nerve fibers that modulates afferent signals resulting in cough, and potentially bronchoconstriction. In the present study, the TRPV1 transcript was detected by RT-PCR in primary cultured human ASM cells, and the TRPV1 protein was detected in ASM of human trachea by immunohistochemistry. Proximity ligation assays suggest that TRPV1 is expressed in the sarcoplasmic reticulum membrane of human ASM cells in close association with sarco/endoplasmic reticulum Ca2+ ATPase 2. In guinea pig tracheal ring organ bath experiments, the TRPV1 agonist capsaicin led to ASM contraction, but this contraction was significantly attenuated by the sodium-channel inhibitor bupivicaine (N=4, p<0.05) and the NK-2 receptor antagonist GR 159897 (N=4, p<0.05), suggesting that this contraction is neurally-mediated. However, pretreatment of guinea pig and human ASM in organ bath experiments with the TRPV1 antagonist capsazepine inhibited the maintenance phase of an acetylcholine-induced contraction (N=4, p<0.01 for both species). Similarly, capsazepine inhibited methacholine-induced contraction of peripheral airways in mouse precision-cut lung slice (PCLS) experiments (N=4-5, p<0.05). Although capsazepine did not inhibit store-operated calicum entry in mouse ASM cells in PCLS (N=4-7, p=NS), it did inhibit calcium oscillations (N=3, p<0.001). These studies suggest that TRPV1 is expressed on ASM, including the SR, but that ASM TRPV1 activation does not play a significant role in initiation of ASM contraction. However, capsazepine does inhibit maintenance of contraction, likely by inhibiting calcium oscillation.

  8. ER reorganization is remarkably induced in COS-7 cells accumulating transmembrane protein receptors not competent for export from the endoplasmic reticulum.

    PubMed

    D'Agostino, Massimo; Crespi, Arianna; Polishchuk, Elena; Generoso, Serena; Martire, Gianluca; Colombo, Sara Francesca; Bonatti, Stefano

    2014-11-01

    The newly synthesized mutant L501fsX533 Frizzled-4 form and the alpha3beta4 nicotinic acetylcholine receptor expressed in the absence of nicotine accumulate in the endoplasmic reticulum of COS-7 cells and induce the formation of large areas of smooth and highly convoluted cisternae. This results in a generalized block of the transport to the Golgi complex of newly synthesized proteins. Intriguingly, both effects happen peculiarly in COS-7 cells; HeLa, Huh-7, and HEK293 cells expressing the two receptors at similar level than COS-7 cells show normal ER and normal transport toward the plasma membrane. These results question the conclusion that a dominant-negative mechanism would explain the dominance of the mutant L501fsX533 Fz4 allele in the transmission of a form of Familial exudative vitreoretinopathy. Moreover, they indicate that the coordination of endoplasmic reticulum homeostasis in COS-7 cells is particularly error prone. This finding suggests that COS-7 cells may be extremely useful to study the molecular mechanisms regulating endoplasmic reticulum size and architecture.

  9. Cubic membranes: a legend beyond the Flatland* of cell membrane organization

    PubMed Central

    Almsherqi, Zakaria A.; Kohlwein, Sepp D.; Deng, Yuru

    2006-01-01

    Cubic membranes represent highly curved, three-dimensional nanoperiodic structures that correspond to mathematically well defined triply periodic minimal surfaces. Although they have been observed in numerous cell types and under different conditions, particularly in stressed, diseased, or virally infected cells, knowledge about the formation and function of nonlamellar, cubic structures in biological systems is scarce, and research so far is restricted to the descriptive level. We show that the “organized smooth endoplasmic reticulum” (OSER; Snapp, E.L., R.S. Hegde, M. Francolini, F. Lombardo, S. Colombo, E. Pedrazzini, N. Borgese, and J. Lippincott-Schwartz. 2003. J. Cell Biol. 163:257–269), which is formed in response to elevated levels of specific membrane-resident proteins, is actually the two-dimensional representation of two subtypes of cubic membrane morphology. Controlled OSER induction may thus provide, for the first time, a valuable tool to study cubic membrane formation and function at the molecular level. PMID:16785319

  10. Translocon pores in the endoplasmic reticulum are permeable to small anions.

    PubMed

    Lizák, Beáta; Czegle, Ibolya; Csala, Miklós; Benedetti, Angelo; Mandl, József; Bánhegyi, Gábor

    2006-09-01

    Contribution of translocon peptide channels to the permeation of low molecular mass anions was investigated in rat liver microsomes. Puromycin, which purges translocon pores of nascent polypeptides, creating additional empty pores, raised the microsomal uptake of radiolabeled UDP-glucuronic acid, while it did not increase the uptake of glucose-6-phosphate or glutathione. The role of translocon pores in the transport of small anions was also investigated by measuring the effect of puromycin on the activity of microsomal enzymes with intraluminal active sites. The mannose-6-phosphatase activity of glucose-6-phosphatase and the activity of UDP-glucuronosyltransferase were elevated upon addition of puromycin, but glucose-6-phosphatase and beta-glucuronidase activities were not changed. The increase in enzyme activities was due to a better access of the substrates to the luminal compartment rather than to activation of the enzymes. Antibody against Sec61 translocon component decreased the activity of UDP-glucuronosyltransferase and antagonized the effect of puromycin. Similarly, the addition of the puromycin antagonist anisomycin or treatments of microsomes, resulting in the release of attached ribosomes, prevented the puromycin-dependent increase in the activity. Mannose-6-phosphatase and UDP-glucuronosyltransferase activities of smooth microsomal vesicles showed higher basal latencies that were not affected by puromycin. In conclusion, translationally inactive, ribosome-bound translocons allow small anions to cross the endoplasmic reticulum membrane. This pathway can contribute to the nonspecific substrate supply of enzymes with intraluminal active centers.

  11. Homocysteine-induced endoplasmic reticulum stress causes dysregulation of the cholesterol and triglyceride biosynthetic pathways

    PubMed Central

    Werstuck, Geoff H.; Lentz, Steven R.; Dayal, Sanjana; Hossain, Gazi S.; Sood, Sudesh K.; Shi, Yuan Y.; Zhou, Ji; Maeda, Nobuyo; Krisans, Skaidrite K.; Malinow, M. Rene; Austin, Richard C.

    2001-01-01

    Hepatic steatosis is common in patients having severe hyperhomocysteinemia due to deficiency for cystathionine β-synthase. However, the mechanism by which homocysteine promotes the development and progression of hepatic steatosis is unknown. We report here that homocysteine-induced endoplasmic reticulum (ER) stress activates both the unfolded protein response and the sterol regulatory element–binding proteins (SREBPs) in cultured human hepatocytes as well as vascular endothelial and aortic smooth muscle cells. Activation of the SREBPs is associated with increased expression of genes responsible for cholesterol/triglyceride biosynthesis and uptake and with intracellular accumulation of cholesterol. Homocysteine-induced gene expression was inhibited by overexpression of the ER chaperone, GRP78/BiP, thus demonstrating a direct role of ER stress in the activation of cholesterol/triglyceride biosynthesis. Consistent with these in vitro findings, cholesterol and triglycerides were significantly elevated in the livers, but not plasmas, of mice having diet-induced hyperhomocysteinemia. This effect was not due to impaired hepatic export of lipids because secretion of VLDL-triglyceride was increased in hyperhomocysteinemic mice. These findings suggest a mechanism by which homocysteine-induced ER stress causes dysregulation of the endogenous sterol response pathway, leading to increased hepatic biosynthesis and uptake of cholesterol and triglycerides. Furthermore, this mechanism likely explains the development and progression of hepatic steatosis and possibly atherosclerotic lesions observed in hyperhomocysteinemia. PMID:11375416

  12. Reduction of endoplasmic reticulum stress inhibits neointima formation after vascular injury.

    PubMed

    Ishimura, Shutaro; Furuhashi, Masato; Mita, Tomohiro; Fuseya, Takahiro; Watanabe, Yuki; Hoshina, Kyoko; Kokubu, Nobuaki; Inoue, Katsumi; Yoshida, Hideaki; Miura, Tetsuji

    2014-11-06

    Endoplasmic reticulum (ER) stress and inappropriate adaptation through the unfolded protein response (UPR) are predominant features of pathological processes. However, little is known about the link between ER stress and endovascular injury. We investigated the involvement of ER stress in neointima hyperplasia after vascular injury. The femoral arteries of 7-8-week-old male mice were subjected to wire-induced vascular injury. After 4 weeks, immunohistological analysis showed that ER stress markers were upregulated in the hyperplastic neointima. Neointima formation was increased by 54.8% in X-box binding protein-1 (XBP1) heterozygous mice, a model of compromised UPR. Knockdown of Xbp1 in human coronary artery smooth muscle cells (CASMC) in vitro promoted cell proliferation and migration. Furthermore, treatment with ER stress reducers, 4-phenylbutyrate (4-PBA) and tauroursodeoxycholic acid (TUDCA), decreased the intima-to-media ratio after wire injury by 50.0% and 72.8%, respectively. Chronic stimulation of CASMC with PDGF-BB activated the UPR, and treatment with 4-PBA and TUDCA significantly suppressed the PDGF-BB-induced ER stress markers in CASMC and the proliferation and migration of CASMC. In conclusion, increased ER stress contributes to neointima formation after vascular injury, while UPR signaling downstream of XBP1 plays a suppressive role. Suppression of ER stress would be a novel strategy against post-angioplasty vascular restenosis.

  13. Quantitative Proteomics and Lipidomics Analysis of Endoplasmic Reticulum of Macrophage Infected with Mycobacterium tuberculosis

    PubMed Central

    Saquib, Najmuddin Mohd; Jamwal, Shilpa; Midha, Mukul Kumar; Verma, Hirdya Narain; Manivel, Venkatasamy

    2015-01-01

    Even though endoplasmic reticulum (ER) stress associated with mycobacterial infection has been well studied, the molecular basis of ER as a crucial organelle to determine the fate of Mtb is yet to be established. Here, we have studied the ability of Mtb to manipulate the ultrastructural architecture of macrophage ER and found that the ER-phenotypes associated with virulent (H37Rv) and avirulent (H37Ra) strains were different: a rough ER (RER) with the former against a smooth ER (SER) with the later. Further, the functional attributes of these changes were probed by MS-based quantitative proteomics (133 ER proteins) and lipidomics (8 phospholipids). Our omics approaches not only revealed the host pathogen cross-talk but also emphasized how precisely Mtb uses proteins and lipids in combination to give rise to characteristic ER-phenotypes. H37Ra-infected macrophages increased the cytosolic Ca2+ levels by attenuating the ATP2A2 protein and simultaneous induction of PC/PE expression to facilitate apoptosis. However, H37Rv inhibited apoptosis and further controlled the expression of EST-1 and AMRP proteins to disturb cholesterol homeostasis resulting in sustained infection. This approach offers the potential to decipher the specific roles of ER in understanding the cell biology of mycobacterial infection with special reference to the impact of host response. PMID:25785198

  14. The endoplasmic reticulum stress response: A link with tuberculosis?

    PubMed

    Cui, Yongyong; Zhao, Deming; Barrow, Paul Andrew; Zhou, Xiangmei

    2016-03-01

    Tuberculosis (TB) remains a major cause of mortality and morbidity in the worldwide. The endoplasmic-reticulum stress (ERS) response constitutes a cellular process that is triggered by mycobacterial infection that disturbs the folding of proteins in the endoplasmic reticulum (ER). The unfolded protein response (UPR) is induced to suspend the synthesis of early proteins and reduce the accumulation of unfolded- or misfolded proteins in the ER restoring normal physiological cell function. Prolonged or uncontrolled ERS leads to the activation of three signaling pathways (IRE1, PERK and ATF6) which directs the cell towards apoptosis. The absence of this process facilitates spread of the mycobacteria within the body. We summarize here recent advances in understanding the signaling pathway diversity governing ERS in relation to TB.

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

    PubMed

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

    2016-09-01

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

  16. [Collagen abnormalities and endoplasmic reticulum stress in bone and cartilage].

    PubMed

    Furuichi, Tatsuya; Nishimura, Gen; Ikegawa, Shiro

    2013-11-01

    There are many steps in the post-translational modification of collagen molecules. When abnormality occurs in some step, the unfolded collagen molecules are accumulated in the endoplasmic reticulum (ER) , leading to ER stress. ER stress also occurs downstream of the defective modification of collagen in bone and cartilage. ER stress-induced apoptosis or ER stress response without inducing apoptosis may be associated with the pathogenesis of genetic collagen disorders in bone and cartilage.

  17. Endoplasmic reticulum stress: implications for inflammatory bowel disease pathogenesis

    PubMed Central

    Kaser, Arthur; Martínez-Naves, Eduardo; Blumberg, Richard S.

    2015-01-01

    Purpose of review To provide an overview of the emerging role of cellular stress responses in inflammatory bowel disease (IBD). Recent findings The unfolded protein response (UPR) is a primitive cellular pathway that is engaged when responding to endoplasmic reticulum stress and regulates autophagy. Highly secretory cells such as Paneth cells and goblet cells in the intestines are particularly susceptible to endoplasmic reticulum stress and are exceedingly dependent upon a properly functioning UPR to maintain cellular viability and homeostasis. Primary genetic abnormalities within the components of the UPR (e.g. XBP1, ARG2, ORMDL3), genes that encode proteins reliant upon a robust secretory pathway (e.g. MUC2, HLAB27) and environmental factors that create disturbances in the UPR (e.g. microbial products and inflammatory cytokines) are important factors in the primary development and/or perpetuation of intestinal inflammation. Summary Endoplasmic reticulum stress is an important new pathway involved in the development of intestinal inflammation associated with IBD and likely other intestinal inflammatory disorders. PMID:20495455

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

    PubMed Central

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

    2014-01-01

    Spinal and bulbar muscular atrophy is an X-linked degenerative motor neuron disease caused by an abnormal expansion in the polyglutamine encoding CAG repeat of the androgen receptor gene. There is evidence implicating endoplasmic reticulum stress in the development and progression of neurodegenerative disease, including polyglutamine disorders such as Huntington’s disease and in motor neuron disease, where cellular stress disrupts functioning of the endoplasmic reticulum, leading to induction of the unfolded protein response. We examined whether endoplasmic reticulum stress is also involved in the pathogenesis of spinal and bulbar muscular atrophy. Spinal and bulbar muscular atrophy mice that carry 100 pathogenic polyglutamine repeats in the androgen receptor, and develop a late-onset neuromuscular phenotype with motor neuron degeneration, were studied. We observed a disturbance in endoplasmic reticulum-associated calcium homeostasis in cultured embryonic motor neurons from spinal and bulbar muscular atrophy mice, which was accompanied by increased endoplasmic reticulum stress. Furthermore, pharmacological inhibition of endoplasmic reticulum stress reduced the endoplasmic reticulum-associated cell death pathway. Examination of spinal cord motor neurons of pathogenic mice at different disease stages revealed elevated expression of markers for endoplasmic reticulum stress, confirming an increase in this stress response in vivo. Importantly, the most significant increase was detected presymptomatically, suggesting that endoplasmic reticulum stress may play an early and possibly causal role in disease pathogenesis. Our results therefore indicate that the endoplasmic reticulum stress pathway could potentially be a therapeutic target for spinal and bulbar muscular atrophy and related polyglutamine diseases. PMID:24898351

  19. Analytic elements of smooth shapes

    NASA Astrophysics Data System (ADS)

    Strack, Otto D. L.; Nevison, Patrick R.

    2015-10-01

    We present a method for producing analytic elements of a smooth shape, obtained using conformal mapping. Applications are presented for a case of impermeable analytic elements as well as for head-specified ones. The mathematical operations necessary to use the elements in practical problems can be carried out before modeling of flow problems begins. A catalog of shapes, along with pre-determined coefficients could be established on the basis of the approach presented here, making applications in the field straight forward.

  20. Orai channel-mediated Ca2+ signals in vascular and airway smooth muscle

    PubMed Central

    Spinelli, Amy M.

    2016-01-01

    Orai (Orai1, Orai2, and Orai3) proteins form a family of highly Ca2+-selective plasma membrane channels that are regulated by stromal-interacting molecules (STIM1 and STIM2); STIM proteins are Ca2+ sensors located in the membrane of the endoplasmic reticulum. STIM and Orai proteins are expressed in vascular and airway smooth muscle and constitute the molecular components of the ubiquitous store-operated Ca2+ entry pathway that mediate the Ca2+ release-activated Ca2+ current. STIM/Orai proteins also encode store-independent Ca2+ entry pathways in smooth muscle. Altered expression and function of STIM/Orai proteins have been linked to vascular and airway pathologies, including restenosis, hypertension, and atopic asthma. In this review we discuss our current understanding of Orai proteins and the store-dependent and -independent signaling pathways mediated by these proteins in vascular and airway smooth muscle. We also discuss the current studies linking altered expression and function of Orai proteins with smooth muscle-related pathologies. PMID:26718630

  1. Organics.

    ERIC Educational Resources Information Center

    Chian, Edward S. K.; DeWalle, Foppe B.

    1978-01-01

    Presents water analysis literature for 1978. This review is concerned with organics, and it covers: (1) detergents and surfactants; (2) aliphatic and aromatic hydrocarbons; (3) pesticides and chlorinated hydrocarbons; and (4) naturally occurring organics. A list of 208 references is also presented. (HM)

  2. Organizers.

    ERIC Educational Resources Information Center

    Callison, Daniel

    2000-01-01

    Focuses on "organizers," tools or techniques that provide identification and classification along with possible relationships or connections among ideas, concepts, and issues. Discusses David Ausubel's research and ideas concerning advance organizers; the implications of Ausubel's theory to curriculum and teaching; "webbing," a…

  3. Organics.

    ERIC Educational Resources Information Center

    Chian, Edward S. K.; DeWalle, Foppe B.

    1978-01-01

    Presents water analysis literature for 1978. This review is concerned with organics, and it covers: (1) detergents and surfactants; (2) aliphatic and aromatic hydrocarbons; (3) pesticides and chlorinated hydrocarbons; and (4) naturally occurring organics. A list of 208 references is also presented. (HM)

  4. Organizers.

    ERIC Educational Resources Information Center

    Callison, Daniel

    2000-01-01

    Focuses on "organizers," tools or techniques that provide identification and classification along with possible relationships or connections among ideas, concepts, and issues. Discusses David Ausubel's research and ideas concerning advance organizers; the implications of Ausubel's theory to curriculum and teaching; "webbing," a…

  5. Inhibitory action of relaxin on human cervical smooth muscle.

    PubMed

    Norström, A; Bryman, I; Wiqvist, N; Sahni, S; Lindblom, B

    1984-09-01

    The influence of purified porcine relaxin on contractility of human cervical smooth muscle was investigated in vitro. Strips of cervical tissue were obtained by needle biopsy from pregnant and nonpregnant women and were mounted in a superfused organ chamber for isometric measurement of contractile activity. Relaxin (0.005-25 micrograms/ml) inhibited the spontaneous contractions in cervical strips from 18% of nonpregnant, 68% of early pregnant, and in 100% of term pregnant women. These results indicate that relaxin has an inhibitory action on cervical smooth muscle and that this effect is more constantly detected as pregnancy proceeds.

  6. Tape-Smoothing Tool For Adhesion Tests

    NASA Technical Reports Server (NTRS)

    Allen, Peter B.

    1992-01-01

    Small tool smoothes adhesive tape uniformly to ensure consistency and repeatability of tape-peel tests of adhesion of paint to substrate. Includes resilient pad covered with tough, smooth fabric. Internal spring regulates force applied to tape.

  7. Segregation of the polypeptide translocation apparatus to regions of the endoplasmic reticulum containing ribophorins and ribosomes. I. Functional tests on rat liver microsomal subfractions

    PubMed Central

    1984-01-01

    A preparation of rat liver microsomes containing 70% of the total cellular endoplasmic reticulum (ER) membranes was subfractionated by isopycnic density centrifugation. Twelve subfractions of different ribosome content ranging in density from 1.06 to 1.29 were obtained and analyzed with respect to marker enzymes, RNA, and protein content, as well as the capacity of these membranes to bind 80S ribosomes in vitro. After removal of native polysomes from these microsomal subfractions by puromycin in a buffer of high ionic strength their capacity to rebind 80S ribosomes approached levels found in the corresponding native membranes before ribosome stripping. This indicates that in vitro rebinding of ribosomes occurs to the same sites occupied in the cell by membrane-bound polysomes. Microsomes in the microsomal subfractions were also tested for their capacity to effect the translocation of nascent secretory proteins into the microsomal lumen utilizing a rabbit reticulocyte translation system programmed with mRNA coding for the precursor of human placental lactogen. Membranes from microsomes with the higher isopycnic density and a high ribosome content showed the highest translocation activity, whereas membranes derived from smooth microsomes had only a very low translocation activity. These results indicate the membranes of the rough and smooth portions of the endoplasmic reticulum are functionally differentiated so that sites for ribosome binding and the translocation of nascent polypeptides are segregated to the rough domain of the organelle. PMID:6501423

  8. Plasma membrane domains enriched in cortical endoplasmic reticulum function as membrane protein trafficking hubs.

    PubMed

    Fox, Philip D; Haberkorn, Christopher J; Weigel, Aubrey V; Higgins, Jenny L; Akin, Elizabeth J; Kennedy, Matthew J; Krapf, Diego; Tamkun, Michael M

    2013-09-01

    In mammalian cells, the cortical endoplasmic reticulum (cER) is a network of tubules and cisterns that lie in close apposition to the plasma membrane (PM). We provide evidence that PM domains enriched in underlying cER function as trafficking hubs for insertion and removal of PM proteins in HEK 293 cells. By simultaneously visualizing cER and various transmembrane protein cargoes with total internal reflectance fluorescence microscopy, we demonstrate that the majority of exocytotic delivery events for a recycled membrane protein or for a membrane protein being delivered to the PM for the first time occur at regions enriched in cER. Likewise, we observed recurring clathrin clusters and functional endocytosis of PM proteins preferentially at the cER-enriched regions. Thus the cER network serves to organize the molecular machinery for both insertion and removal of cell surface proteins, highlighting a novel role for these unique cellular microdomains in membrane trafficking.

  9. 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

  10. A SAS IML Macro for Loglinear Smoothing

    ERIC Educational Resources Information Center

    Moses, Tim; von Davier, Alina

    2011-01-01

    Polynomial loglinear models for one-, two-, and higher-way contingency tables have important applications to measurement and assessment. They are essentially regarded as a smoothing technique, which is commonly referred to as loglinear smoothing. A SAS IML (SAS Institute, 2002a) macro was created to implement loglinear smoothing according to…

  11. 7 CFR 51.768 - Smooth texture.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size of the fruit. “Thin” means that the skin thickness does not average more than 3/8 inch (9.5 mm), on a...

  12. 7 CFR 51.768 - Smooth texture.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size of the fruit. “Thin” means that the skin thickness does not average more than 3/8 inch (9.5 mm), on a...

  13. Beamline smoothing of the Advanced Photon Source

    SciTech Connect

    Friedsam, H.; Penicka, M.; Zhao, S.

    1995-06-01

    This paper outlines a general beamline smoothing concept based on the use of First Principle Component analysis. Bean-dine smoothing is commonly used for the detection of blunders in the positioning of beam elements and to provide a smooth particle beam path with the fewest adjustments to individual beam components. It also provides the data for assessment of the achieved positioning quality.

  14. Effectiveness of Analytic Smoothing in Equipercentile Equating.

    ERIC Educational Resources Information Center

    Kolen, Michael J.

    1984-01-01

    An analytic procedure for smoothing in equipercentile equating using cubic smoothing splines is described and illustrated. The effectiveness of the procedure is judged by comparing the results from smoothed equipercentile equating with those from other equating methods using multiple cross-validations for a variety of sample sizes. (Author/JKS)

  15. A SAS IML Macro for Loglinear Smoothing

    ERIC Educational Resources Information Center

    Moses, Tim; von Davier, Alina

    2011-01-01

    Polynomial loglinear models for one-, two-, and higher-way contingency tables have important applications to measurement and assessment. They are essentially regarded as a smoothing technique, which is commonly referred to as loglinear smoothing. A SAS IML (SAS Institute, 2002a) macro was created to implement loglinear smoothing according to…

  16. 7 CFR 51.1910 - Fairly smooth.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Fairly smooth. 51.1910 Section 51.1910 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... smooth. Fairly smooth means that the tomato is not conspicuously ridged or rough. ...

  17. 7 CFR 51.1910 - Fairly smooth.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Fairly smooth. 51.1910 Section 51.1910 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Consumer Standards for Fresh Tomatoes Definitions § 51.1910 Fairly smooth. Fairly smooth means that the...

  18. 7 CFR 51.1870 - Fairly smooth.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Fairly smooth. 51.1870 Section 51.1870 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Fresh Tomatoes 1 Definitions § 51.1870 Fairly smooth. Fairly smooth means that the tomato is...

  19. 7 CFR 51.1910 - Fairly smooth.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Fairly smooth. 51.1910 Section 51.1910 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Consumer Standards for Fresh Tomatoes Definitions § 51.1910 Fairly smooth. Fairly smooth means that the...

  20. 7 CFR 51.1910 - Fairly smooth.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Fairly smooth. 51.1910 Section 51.1910 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... smooth. Fairly smooth means that the tomato is not conspicuously ridged or rough. ...

  1. 7 CFR 51.1870 - Fairly smooth.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Fairly smooth. 51.1870 Section 51.1870 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Fresh Tomatoes 1 Definitions § 51.1870 Fairly smooth. Fairly smooth means that the tomato is...

  2. 7 CFR 51.1910 - Fairly smooth.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Fairly smooth. 51.1910 Section 51.1910 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Consumer Standards for Fresh Tomatoes Definitions § 51.1910 Fairly smooth. Fairly smooth means that the...

  3. 7 CFR 51.1870 - Fairly smooth.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Fairly smooth. 51.1870 Section 51.1870 Agriculture..., CERTIFICATION, AND STANDARDS) United States Standards for Fresh Tomatoes 1 Definitions § 51.1870 Fairly smooth. Fairly smooth means that the tomato is not conspicuously ridged or rough. ...

  4. 7 CFR 51.1870 - Fairly smooth.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Fairly smooth. 51.1870 Section 51.1870 Agriculture..., CERTIFICATION, AND STANDARDS) United States Standards for Fresh Tomatoes 1 Definitions § 51.1870 Fairly smooth. Fairly smooth means that the tomato is not conspicuously ridged or rough. ...

  5. Effectiveness of Analytic Smoothing in Equipercentile Equating.

    ERIC Educational Resources Information Center

    Kolen, Michael J.

    1984-01-01

    An analytic procedure for smoothing in equipercentile equating using cubic smoothing splines is described and illustrated. The effectiveness of the procedure is judged by comparing the results from smoothed equipercentile equating with those from other equating methods using multiple cross-validations for a variety of sample sizes. (Author/JKS)

  6. Distribution of alpha-vascular smooth muscle actin in the smooth muscle cells of the gastrointestinal tract of the chicken.

    PubMed Central

    Yamamoto, Y; Kubota, T; Atoji, Y; Suzuki, Y

    1996-01-01

    Immunoreactivity specific for alpha-vascular smooth muscle actin (ASMA) was examined in the enteric smooth muscle cells along the entire length of the gastrointestinal tract of the chicken. Specificity for gamma-smooth muscle actin (GSMA) and desmin was also examined. All smooth muscle layers, i.e. the muscularis mucosae, and the circular and longitudinal muscle layers, showed immunoreactivity specific for GSMA and desmin throughout the gastrointestinal tract whereas immunoreactivity for ASMA differed between regions and muscle layers. In the oesophagus and crop, immunoreactivity for ASMA was observed in the muscularis mucosae and the inner and outer muscle layers, together with staining for GSMA and desmin. In the proventriculus, immunoreactivity for ASMA was observed in all smooth muscle cells in the inner layer of the muscularis mucosae and the longitudinal muscle layer. In the outer layer of the muscularis mucosae, immunoreactivity for ASMA on smooth muscle cells was observed on the luminal side and decreased in the serosal direction. In the intermediate muscles, immunoreactivity for ASMA was observed in the luminal portion, the intensity of staining decreasing gradually in the serosal direction. In contrast to the intermediate muscles, the latter muscles were negative for ASMA. In the pyloric region, the outer part was weakly immunopositive, while the inner part was intensely positive. In the small and large intestines, the muscularis mucosae and the longitudinal muscle layer were positive for ASMA. The outer part of the circular muscle layer was immunonegative for ASMA whereas the inner part was positive. The complex structure and contractile functions of each organ and muscle layers may be related to the difference patterns of expression of ASMA molecules in the smooth muscle cells. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:8982838

  7. Boundary smoothness of analytic functions

    NASA Astrophysics Data System (ADS)

    O'Farrell, Anthony G.

    2014-06-01

    We consider the behaviour of holomorphic functions on a bounded open subset of the plane, satisfying a Lipschitz condition with exponent , with , in the vicinity of an exceptional boundary point where all such functions exhibit some kind of smoothness. Specifically, we consider the relation between the abstract idea of a bounded point derivation on the algebra of such functions and the classical complex derivative evaluated as a limit of difference quotients. We obtain a result which applies, for example, when the open set admits an interior cone at the special boundary point.

  8. Fibronectin matrix polymerization regulates smooth muscle cell phenotype through a Rac1 dependent mechanism.

    PubMed

    Shi, Feng; Long, Xiaochun; Hendershot, Allison; Miano, Joseph M; Sottile, Jane

    2014-01-01

    Smooth muscle cells are maintained in a differentiated state in the vessel wall, but can be modulated to a synthetic phenotype following injury. Smooth muscle phenotypic modulation is thought to play an important role in the pathology of vascular occlusive diseases. Phenotypically modulated smooth muscle cells exhibit increased proliferative and migratory properties that accompany the downregulation of smooth muscle cell marker proteins. Extracellular matrix proteins, including fibronectin, can regulate the smooth muscle phenotype when used as adhesive substrates. However, cells produce and organize a 3-dimensional fibrillar extracellular matrix, which can affect cell behavior in distinct ways from the protomeric 2-dimensional matrix proteins that are used as adhesive substrates. We previously showed that the deposition/polymerization of fibronectin into the extracellular matrix can regulate the deposition and organization of other extracellular matrix molecules in vitro. Further, our published data show that the presence of a fibronectin polymerization inhibitor results in increased expression of smooth muscle cell differentiation proteins and inhibits vascular remodeling in vivo. In this manuscript, we used an in vitro cell culture system to determine the mechanism by which fibronectin polymerization affects smooth muscle phenotypic modulation. Our data show that fibronectin polymerization decreases the mRNA levels of multiple smooth muscle differentiation genes, and downregulates the levels of smooth muscle α-actin and calponin proteins by a Rac1-dependent mechanism. The expression of smooth muscle genes is transcriptionally regulated by fibronectin polymerization, as evidenced by the increased activity of luciferase reporter constructs in the presence of a fibronectin polymerization inhibitor. Fibronectin polymerization also promotes smooth muscle cell growth, and decreases the levels of actin stress fibers. These data define a Rac1-dependent pathway wherein

  9. Protein misfolding in the endoplasmic reticulum as a conduit to human disease.

    PubMed

    Wang, Miao; Kaufman, Randal J

    2016-01-21

    In eukaryotic cells, the endoplasmic reticulum is essential for the folding and trafficking of proteins that enter the secretory pathway. Environmental insults or increased protein synthesis often lead to protein misfolding in the organelle, the accumulation of misfolded or unfolded proteins - known as endoplasmic reticulum stress - and the activation of the adaptive unfolded protein response to restore homeostasis. If protein misfolding is not resolved, cells die. Endoplasmic reticulum stress and activation of the unfolded protein response help to determine cell fate and function. Furthermore, endoplasmic reticulum stress contributes to the aetiology of many human diseases.

  10. Improving smoothing efficiency of rigid conformal polishing tool using time-dependent smoothing evaluation model

    NASA Astrophysics Data System (ADS)

    Song, Chi; Zhang, Xuejun; Zhang, Xin; Hu, Haifei; Zeng, Xuefeng

    2017-06-01

    A rigid conformal (RC) lap can smooth mid-spatial-frequency (MSF) errors, which are naturally smaller than the tool size, while still removing large-scale errors in a short time. However, the RC-lap smoothing efficiency performance is poorer than expected, and existing smoothing models cannot explicitly specify the methods to improve this efficiency. We presented an explicit time-dependent smoothing evaluation model that contained specific smoothing parameters directly derived from the parametric smoothing model and the Preston equation. Based on the time-dependent model, we proposed a strategy to improve the RC-lap smoothing efficiency, which incorporated the theoretical model, tool optimization, and efficiency limit determination. Two sets of smoothing experiments were performed to demonstrate the smoothing efficiency achieved using the time-dependent smoothing model. A high, theory-like tool influence function and a limiting tool speed of 300 RPM were o

  11. Improving smoothing efficiency of rigid conformal polishing tool using time-dependent smoothing evaluation model

    NASA Astrophysics Data System (ADS)

    Song, Chi; Zhang, Xuejun; Zhang, Xin; Hu, Haifei; Zeng, Xuefeng

    2017-01-01

    A rigid conformal (RC) lap can smooth mid-spatial-frequency (MSF) errors, which are naturally smaller than the tool size, while still removing large-scale errors in a short time. However, the RC-lap smoothing efficiency performance is poorer than expected, and existing smoothing models cannot explicitly specify the methods to improve this efficiency. We presented an explicit time-dependent smoothing evaluation model that contained specific smoothing parameters directly derived from the parametric smoothing model and the Preston equation. Based on the time-dependent model, we proposed a strategy to improve the RC-lap smoothing efficiency, which incorporated the theoretical model, tool optimization, and efficiency limit determination. Two sets of smoothing experiments were performed to demonstrate the smoothing efficiency achieved using the time-dependent smoothing model. A high, theory-like tool influence function and a limiting tool speed of 300 RPM were o

  12. Smooth halos in the cosmic web

    NASA Astrophysics Data System (ADS)

    Gaite, José

    2015-04-01

    Dark matter halos can be defined as smooth distributions of dark matter placed in a non-smooth cosmic web structure. This definition of halos demands a precise definition of smoothness and a characterization of the manner in which the transition from smooth halos to the cosmic web takes place. We introduce entropic measures of smoothness, related to measures of inequality previously used in economy and with the advantage of being connected with standard methods of multifractal analysis already used for characterizing the cosmic web structure in cold dark matter N-body simulations. These entropic measures provide us with a quantitative description of the transition from the small scales portrayed as a distribution of halos to the larger scales portrayed as a cosmic web and, therefore, allow us to assign definite sizes to halos. However, these ``smoothness sizes'' have no direct relation to the virial radii. Finally, we discuss the influence of N-body discreteness parameters on smoothness.

  13. Smooth halos in the cosmic web

    SciTech Connect

    Gaite, José

    2015-04-01

    Dark matter halos can be defined as smooth distributions of dark matter placed in a non-smooth cosmic web structure. This definition of halos demands a precise definition of smoothness and a characterization of the manner in which the transition from smooth halos to the cosmic web takes place. We introduce entropic measures of smoothness, related to measures of inequality previously used in economy and with the advantage of being connected with standard methods of multifractal analysis already used for characterizing the cosmic web structure in cold dark matter N-body simulations. These entropic measures provide us with a quantitative description of the transition from the small scales portrayed as a distribution of halos to the larger scales portrayed as a cosmic web and, therefore, allow us to assign definite sizes to halos. However, these ''smoothness sizes'' have no direct relation to the virial radii. Finally, we discuss the influence of N-body discreteness parameters on smoothness.

  14. s-SMOOTH: Sparsity and Smoothness Enhanced EEG Brain Tomography

    PubMed Central

    Li, Ying; Qin, Jing; Hsin, Yue-Loong; Osher, Stanley; Liu, Wentai

    2016-01-01

    EEG source imaging enables us to reconstruct current density in the brain from the electrical measurements with excellent temporal resolution (~ ms). The corresponding EEG inverse problem is an ill-posed one that has infinitely many solutions. This is due to the fact that the number of EEG sensors is usually much smaller than that of the potential dipole locations, as well as noise contamination in the recorded signals. To obtain a unique solution, regularizations can be incorporated to impose additional constraints on the solution. An appropriate choice of regularization is critically important for the reconstruction accuracy of a brain image. In this paper, we propose a novel Sparsity and SMOOthness enhanced brain TomograpHy (s-SMOOTH) method to improve the reconstruction accuracy by integrating two recently proposed regularization techniques: Total Generalized Variation (TGV) regularization and ℓ1−2 regularization. TGV is able to preserve the source edge and recover the spatial distribution of the source intensity with high accuracy. Compared to the relevant total variation (TV) regularization, TGV enhances the smoothness of the image and reduces staircasing artifacts. The traditional TGV defined on a 2D image has been widely used in the image processing field. In order to handle 3D EEG source images, we propose a voxel-based Total Generalized Variation (vTGV) regularization that extends the definition of second-order TGV from 2D planar images to 3D irregular surfaces such as cortex surface. In addition, the ℓ1−2 regularization is utilized to promote sparsity on the current density itself. We demonstrate that ℓ1−2 regularization is able to enhance sparsity and accelerate computations than ℓ1 regularization. The proposed model is solved by an efficient and robust algorithm based on the difference of convex functions algorithm (DCA) and the alternating direction method of multipliers (ADMM). Numerical experiments using synthetic data demonstrate the

  15. s-SMOOTH: Sparsity and Smoothness Enhanced EEG Brain Tomography.

    PubMed

    Li, Ying; Qin, Jing; Hsin, Yue-Loong; Osher, Stanley; Liu, Wentai

    2016-01-01

    EEG source imaging enables us to reconstruct current density in the brain from the electrical measurements with excellent temporal resolution (~ ms). The corresponding EEG inverse problem is an ill-posed one that has infinitely many solutions. This is due to the fact that the number of EEG sensors is usually much smaller than that of the potential dipole locations, as well as noise contamination in the recorded signals. To obtain a unique solution, regularizations can be incorporated to impose additional constraints on the solution. An appropriate choice of regularization is critically important for the reconstruction accuracy of a brain image. In this paper, we propose a novel Sparsity and SMOOthness enhanced brain TomograpHy (s-SMOOTH) method to improve the reconstruction accuracy by integrating two recently proposed regularization techniques: Total Generalized Variation (TGV) regularization and ℓ1-2 regularization. TGV is able to preserve the source edge and recover the spatial distribution of the source intensity with high accuracy. Compared to the relevant total variation (TV) regularization, TGV enhances the smoothness of the image and reduces staircasing artifacts. The traditional TGV defined on a 2D image has been widely used in the image processing field. In order to handle 3D EEG source images, we propose a voxel-based Total Generalized Variation (vTGV) regularization that extends the definition of second-order TGV from 2D planar images to 3D irregular surfaces such as cortex surface. In addition, the ℓ1-2 regularization is utilized to promote sparsity on the current density itself. We demonstrate that ℓ1-2 regularization is able to enhance sparsity and accelerate computations than ℓ1 regularization. The proposed model is solved by an efficient and robust algorithm based on the difference of convex functions algorithm (DCA) and the alternating direction method of multipliers (ADMM). Numerical experiments using synthetic data demonstrate the

  16. Rhythmicity in arterial smooth muscle

    PubMed Central

    Haddock, Rebecca E; Hill, Caryl E

    2005-01-01

    Many arteries and arterioles exhibit rhythmical contractions which are synchronous over considerable distances. This vasomotion is likely to assist in tissue perfusion especially during periods of altered metabolism or perfusion pressure. While the mechanism underlying vascular rhythmicity has been investigated for many years, it has only been recently, with the advent of imaging techniques for visualizing intracellular calcium release, that significant advances have been made. These methods, when combined with mechanical and electrophysiological recordings, have demonstrated that the rhythm depends critically on calcium released from intracellular stores within the smooth muscle cells and on cell coupling via gap junctions to synchronize oscillations in calcium release amongst adjacent cells. While these factors are common to all vessels studied to date, the contribution of voltage-dependent channels and the endothelium varies amongst different vessels. The basic mechanism for rhythmical activity in arteries thus differs from its counterpart in non-vascular smooth muscle, where specific networks of pacemaker cells generate electrical potentials which drive activity within the otherwise quiescent muscle cells. PMID:15905215

  17. Standard-smooth hybrid inflation

    SciTech Connect

    Lazarides, George; Vamvasakis, Achilleas

    2007-12-15

    We consider the extended supersymmetric Pati-Salam model which, for {mu}>0 and universal boundary conditions, succeeds to yield experimentally acceptable b-quark masses by moderately violating Yukawa unification. It is known that this model can lead to new shifted or new smooth hybrid inflation. We show that a successful two-stage inflationary scenario can be realized within this model based only on renormalizable superpotential interactions. The cosmological scales exit the horizon during the first stage of inflation, which is of the standard hybrid type and takes place along the trivial flat direction with the inflaton driven by radiative corrections. Spectral indices compatible with the recent data can be achieved in global supersymmetry or minimal supergravity by restricting the number of e-foldings of our present horizon during the first inflationary stage. The additional e-foldings needed for solving the horizon and flatness problems are naturally provided by a second stage of inflation, which occurs mainly along the built-in new smooth hybrid inflationary path appearing right after the destabilization of the trivial flat direction at its critical point. Monopoles are formed at the end of the first stage of inflation and are, subsequently, diluted by the second stage of inflation to become utterly negligible in the present universe for almost all (for all) the allowed values of the parameters in the case of global supersymmetry (minimal supergravity)

  18. Why Are Galaxies So Smooth?

    NASA Image and Video Library

    2009-04-30

    This image from NASA's Spitzer Space Telescope shows the spiral galaxy NGC 2841, located about 46 million light-years from Earth in the constellation Ursa Major. The galaxy is helping astronomers solve one of the oldest puzzles in astronomy: Why do galaxies look so smooth, with stars sprinkled evenly throughout? An international team of astronomers has discovered that rivers of young stars flow from their hot, dense stellar nurseries, dispersing out to form large, smooth distributions. This image is a composite of three different wavelengths from Spitzer's infrared array camera. The shortest wavelengths are displayed inblue, and mostly show the older stars in NGC 2841, as well as foreground stars in our own Milky Way galaxy. The cooler areas are highlighted in red, and show the dusty, gaseous regions of the galaxy. Blue shows infrared light of 3.6 microns, green represents 4.5-micron light and red, 8.0-micron light. The contribution from starlight measured at 3.6 microns has been subtracted from the 8.0-micron data to enhance the visibility of the dust features.The shortest wavelengths are displayed inblue, and mostly show the older stars in NGC 2841, as well as foreground stars in our own Milky Way galaxy. http://photojournal.jpl.nasa.gov/catalog/PIA12001

  19. Lipid trafficking at endoplasmic reticulum-chloroplast membrane contact sites.

    PubMed

    Block, Maryse A; Jouhet, Juliette

    2015-08-01

    Glycerolipid synthesis in plant cells is characterized by an intense trafficking of lipids between the endoplasmic reticulum (ER) and chloroplasts. Initially, fatty acids are synthesized within chloroplasts and are exported to the ER where they are used to build up phospholipids and triacylglycerol. Ultimately, derivatives of these phospholipids return to chloroplasts to form galactolipids, monogalactosyldiacylglycerol and digalactosyldiacylglycerol, the main and essential lipids of photosynthetic membranes. Lipid trafficking was proposed to transit through membrane contact sites (MCSs) connecting both organelles. Here, we review recent insights into ER-chloroplast MCSs and lipid trafficking between chloroplasts and the ER.

  20. Mitochondria-endoplasmic reticulum choreography: structure and signaling dynamics.

    PubMed

    Pizzo, Paola; Pozzan, Tullio

    2007-10-01

    Mitochondria and endoplasmic reticulum (ER) have different roles in living cells but they interact both physically and functionally. A key aspect of the mitochondria-ER relationship is the modulation of Ca(2+) signaling during cell activation, which thus affects a variety of physiological processes. We focus here on the molecular aspects that control the dynamics of the organelle-organelle interaction and their relationship with Ca(2+) signals, also discussing the consequences that these phenomena have, not only for cell physiology but also in the control of cell death.

  1. Physiological functions of endoplasmic reticulum stress transducer OASIS in central nervous system.

    PubMed

    Saito, Atsushi

    2014-01-01

    Eukaryotic cells can adapt to endoplasmic reticulum (ER) dysfunction by producing diverse signals from the ER to the cytosol or nucleus. These signaling pathways are collectively known as the unfolded protein response (UPR). The canonical branches of the UPR are mediated by three ER membrane-bound proteins: double-stranded RNA-dependent protein kinase (PKR)-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme-1 (IRE1) and activating transcription factor 6 (ATF6). These ER stress transducers basically play important roles in cell survival after ER stress. Recently, novel types of ER stress transducers that share a region of high sequence similarity with ATF6 have been identified. They have a transmembrane domain, which allows them to associate with the ER, and possess a transcription-activation domain and a basic leucine zipper (bZIP) domain. These membrane-bound bZIP transcription factors include OASIS, BBF2H7 CREBH, CREB4 and Luman, and are collectively referred to as OASIS family members. Despite their structural similarities with ATF6, differences in activating stimuli and tissue distribution indicate specialized functions of each member on regulating UPR signaling in specific organs and tissues. One of them, OASIS, is expressed preferentially in astrocytes in the central nervous system (CNS). OASIS temporally regulates the differentiation from neural precursor cells into astrocytes to promote the expression of Glial Cell Missing 1 through dynamic interactions among OASIS family members followed by accelerating demethylation of the Gfap promoter. This review is a summary of our current understanding of the physiological functions of OASIS in the CNS.

  2. Smoothing and the second law

    NASA Technical Reports Server (NTRS)

    Merriam, Marshal L.

    1986-01-01

    The technique of obtaining second order, oscillation free, total variation diminishing (TVD), scalar difference schemes by adding a limited diffusion flux (smoothing) to a second order centered scheme is explored. It is shown that such schemes do not always converge to the correct physical answer. The approach presented here is to construct schemes that numerically satisfy the second law of thermodynamics on a cell by cell basis. Such schemes can only converge to the correct physical solution and in some cases can be shown to be TVD. An explicit scheme with this property and second order spatial accuracy was found to have an extremely restrictive time step limitation (Delta t less than Delta x squared). Switching to an implicit scheme removed the time step limitation.

  3. Smoothing and the second law

    NASA Technical Reports Server (NTRS)

    Merriam, Marshal L.

    1987-01-01

    The technique of obtaining second-order oscillation-free total -variation-diminishing (TVD), scalar difference schemes by adding a limited diffusive flux ('smoothing') to a second-order centered scheme is explored. It is shown that such schemes do not always converge to the correct physical answer. The approach presented here is to construct schemes that numerically satisfy the second law of thermodynamics on a cell-by-cell basis. Such schemes can only converge to the correct physical solution and in some cases can be shown to be TVD. An explicit scheme with this property and second-order spatial accuracy was found to have extremely restrictive time-step limitation. Switching to an implicit scheme removed the time-step limitation.

  4. Autoregressive smoothing of GOMOS transmittances

    NASA Astrophysics Data System (ADS)

    Fussen, D.; Vanhellemont, F.; Bingen, C.; Kyrölä, B.; Tamminen, J.; Sofieva, V.; Hassinen, S.; Seppälä, A.; Verronen, P. T.; Bertaux, J. L.; Hauchecorne, A.; Dalaudier, F.; d'Andon, O. Fanton; Barrot, G.; Mangin, A.; Theodore, B.; Guirlet, M.; Renard, J. B.; Fraisse, R.; Snoeij, P.; Koopman, R.; Saavedra, L.

    GOMOS is a stellar occultation instrument onboard ENVISAT. It has already measured several hundreds of thousands occultations since March 2002. In some circumstances, the obliqueness of the star setting causes the remote sounding of possible horizontal turbulence that cannot be adequately corrected by using the fast photometer signals, leading to the presence of residual scintillation in the atmospheric transmittance. We investigate the mechanism that produces this spurious signal that may cause the retrieval of wavy constituent profiles. A special algorithm of vertical autoregressive smoothing (VAS) is proposed that takes into account the physical correlation between adjacent measurements at different tangent altitudes. A regularization parameter of the method may be optimized on basis of the minimal correlation between the residuals as prescribed by the Durbin-Watson statistics. The improvements obtained in the retrieval of both O 3 and NO 2 number density profiles is presented and discussed with respect to the results of the official data processing model.

  5. Wall-crossing made smooth

    NASA Astrophysics Data System (ADS)

    Pioline, Boris

    2015-04-01

    In D = 4 , theories on , the index receives contributions not only from single-particle BPS states, counted by the BPS indices, but also from multi-particle states made of BPS constituents. In a recent work [1], a general formula expressing the index in terms of the BPS indices was proposed, which is smooth across walls of marginal stability and reproduces the expected single-particle contributions. In this note, I analyze the two-particle contributions predicted by this formula, and show agreement with the spectral asymmetry of the continuum of scattering states in the supersymmetric quantum mechanics of two non-relativistic, mutually non-local dyons. This may provide a physical justification for the error function profile used in the mathematics literature on indefinite theta series, and in the physics literature on black hole partition functions.

  6. Lensing smoothing of BAO wiggles

    NASA Astrophysics Data System (ADS)

    Di Dio, Enea

    2017-03-01

    We study non-perturbatively the effect of the deflection angle on the BAO wiggles of the matter power spectrum in real space. We show that from redshift z~2 this introduces a dispersion of roughly 1 Mpc at BAO scale, which corresponds approximately to a 1% effect. The lensing effect induced by the deflection angle, which is completely geometrical and survey independent, smears out the BAO wiggles. The effect on the power spectrum amplitude at BAO scale is about 0.1 % for z~2 and 0.2 % for z~4. We compare the smoothing effects induced by the lensing potential and non-linear structure formation, showing that the two effects become comparable at z ~ 4, while the lensing effect dominates for sources at higher redshifts. We note that this effect is not accounted through BAO reconstruction techniques.

  7. Endoplasmic Reticulum Calcium Pumps and Cancer Cell Differentiation

    PubMed Central

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

    2012-01-01

    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. PMID:24970132

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

    PubMed

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

    2015-11-05

    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.

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

    PubMed Central

    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

  10. 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.

  11. Endoplasmic Reticulum Protein Quality Control Failure in Myelin Disorders

    PubMed Central

    Volpi, Vera G.; Touvier, Thierry; D'Antonio, Maurizio

    2017-01-01

    Reaching the correct three-dimensional structure is crucial for the proper function of a protein. The endoplasmic reticulum (ER) is the organelle where secreted and transmembrane proteins are synthesized and folded. To guarantee high fidelity of protein synthesis and maturation in the ER, cells have evolved ER-protein quality control (ERQC) systems, which assist protein folding and promptly degrade aberrant gene products. Only correctly folded proteins that pass ERQC checkpoints are allowed to exit the ER and reach their final destination. Misfolded glycoproteins are detected and targeted for degradation by the proteasome in a process known as endoplasmic reticulum-associated degradation (ERAD). The excess of unstructured proteins in the ER triggers an adaptive signal transduction pathway, called unfolded protein response (UPR), which in turn potentiates ERQC activities in order to reduce the levels of aberrant molecules. When the situation cannot be restored, the UPR drives cells to apoptosis. Myelin-forming cells of the central and peripheral nervous system (oligodendrocytes and Schwann cells) synthesize a large amount of myelin proteins and lipids and therefore are particularly susceptible to ERQC failure. Indeed, deficits in ERQC and activation of ER stress/UPR have been implicated in several myelin disorders, such as Pelizaeus-Merzbacher and Krabbe leucodystrophies, vanishing white matter disease and Charcot-Marie-Tooth neuropathies. Here we discuss recent evidence underlying the importance of proper ERQC functions in genetic disorders of myelinating glia. PMID:28101003

  12. 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.

  13. An adaptive data-smoothing routine

    NASA Technical Reports Server (NTRS)

    Taylor, Clayborne D.; Nicolas, David P.

    1989-01-01

    An adaptive noise reduction algorithm that can be implemented on a microcomputer is developed. Smoothing polynomials are used where the polynomial coefficients are chosen such that the mean-square-error between the noisy and smoothed data is minimized. This approach is equivalent to the implementation of a low-pass finite impulse response filter. The noise reduction depends on the order of the smoothing polynomial. A whiteness test on the error sequence is incorporated to search for the optimal smoothing. Expansion coefficients may be computed via the fast Fourier transform, and the resulting smoothing process is the equivalent of the implementation of an adaptive ideal low-pass filter. Results are obtained for an analytical signal with added white Gaussian noise. The routine may be applied to any smooth signal with additive random noise.

  14. Capacitative Ca2+ entry and the regulation of smooth muscle tone.

    PubMed

    Gibson, A; McFadzean, I; Wallace, P; Wayman, C P

    1998-07-01

    In many non-excitable cells, activation of phospholipase C-linked receptors results in a biphasic increase in the cytosolic Ca2+ concentration; an initial transient increase, owing to the release of Ca2+ from the endoplasmic/sarcoplasmic reticulum (ER/SR), is followed by a much smaller but sustained elevation, which often involves capacitative Ca2+ entry, where depletion of Ca2+ within the ER signals the opening of store-operated Ca2+ channels in the plasma membrane. However, in excitable cells such as smooth muscle, the role of capacitative Ca2+ entry is less clear and the main Ca2+ entry mechanisms responsible for sustained cellular activation have been considered to be either voltage-operated or receptor-operated Ca2+ channels. Although store-regulated Ca2+ entry was known to occur following agonist activation of smooth muscle, it was believed to be important only for the re-filling of the depleted SR and not as a source of activator Ca2+ for the contractile mechanisms. Here, Alan Gibson, Ian McFadzean, Pat Wallace and Christopher Wayman review recent evidence that capacitative Ca2+ entry might indeed be important for the regulation of smooth muscle tone, and that it might provide an important for pharmacological intervention.

  15. Gating Behavior of Endoplasmic Reticulum Potassium Channels of Rat Hepatocytes in Diabetes

    PubMed Central

    Ghasemi, Maedeh; Khodaei, Naser; Salari, Sajjad; Eliassi, Afsaneh; Saghiri, Reza

    2014-01-01

    Background: Defects in endoplasmic reticulum homeostasis are common occurrences in different diseases, such as diabetes, in which the function of endoplasmic reticulum is disrupted. It is now well established that ion channels of endoplasmic reticulum membrane have a critical role in endoplasmic reticulum luminal homeostasis. Our previous studies showed the presence of an ATP-sensitive cationic channel in endoplasmic reticulum. Therefore, in this study, we examined and compared the activities of this channel in control and diabetic rats using single-channel recording techniques. Method: Male Wistar rats were made diabetic for 2 weeks with a single dose injection of streptozotocin (45 mg/kg). Ion channel incorporation of rough endoplasmic reticulum of diabetic hepatocytes into the bilayer lipid membrane allowed the characterization of K+ channel. Results: Ion channel incorporation of rough endoplasmic reticulum vesicles into the bilayer lipid revealed that the channel current-voltage (I-V) relation with a mean slope conductance of 520 ± 19 pS was unaffected in diabetes. Interestingly, the channel Po-voltage relation was significantly lower in diabetic rats at voltages above +30 mV. Conclusion: We concluded that the endoplasmic reticulum cationic channel is involved in diabetes. Also, this finding could be considered as a goal for further therapeutic plans. PMID:24842143

  16. Unique matrix structure in the rough endoplasmic reticulum cisternae of pseudoachondroplasia chondrocytes.

    PubMed

    Merritt, Thomas M; Bick, Roger; Poindexter, Brian J; Alcorn, Joseph L; Hecht, Jacqueline T

    2007-01-01

    Mutations in cartilage oligomeric matrix protein (COMP) cause two skeletal dysplasias, pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED/EDM1). Because COMP exists as a homopentamer, only one mutant COMP subunit may result in an abnormal complex that is accumulated in expanded rough endoplasmic reticulum (rER) cisternae, a hallmark of PSACH. Type IX collagen and matrilin-3 (MATN3), also accumulate in the rER cisternae of PSACH chondrocytes, but it is unknown how mutant COMP interacts with these proteins. The studies herein focus on defining the organization of these intracellularly retained proteins using fluorescence deconvolution microscopy. A unique matrix organization was identified in which type II procollagen formed a central core surrounded by a protein network of mutant COMP, type IX collagen, and MATN3. This pattern of matrix organization was found in multiple cisternae from single chondrocytes and in chondrocytes with different COMP mutations, indicating a common pattern of interaction. This suggests that stalling of mutant COMP and an interaction between mutant COMP and type II procollagen are initiating events in the assembly of matrix in the rER, possibly explaining why the material is not readily cleared from the rER. Altogether, these data suggest that mutant COMP initiates and perhaps catalyzes premature intracellular matrix assembly.

  17. Unique Matrix Structure in the Rough Endoplasmic Reticulum Cisternae of Pseudoachondroplasia Chondrocytes

    PubMed Central

    Merritt, Thomas M.; Bick, Roger; Poindexter, Brian J.; Alcorn, Joseph L.; Hecht, Jacqueline T.

    2007-01-01

    Mutations in cartilage oligomeric matrix protein (COMP) cause two skeletal dysplasias, pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED/EDM1). Because COMP exists as a homopentamer, only one mutant COMP subunit may result in an abnormal complex that is accumulated in expanded rough endoplasmic reticulum (rER) cisternae, a hallmark of PSACH. Type IX collagen and matrilin-3 (MATN3), also accumulate in the rER cisternae of PSACH chondrocytes, but it is unknown how mutant COMP interacts with these proteins. The studies herein focus on defining the organization of these intracellularly retained proteins using fluorescence deconvolution microscopy. A unique matrix organization was identified in which type II procollagen formed a central core surrounded by a protein network of mutant COMP, type IX collagen, and MATN3. This pattern of matrix organization was found in multiple cisternae from single chondrocytes and in chondrocytes with different COMP mutations, indicating a common pattern of interaction. This suggests that stalling of mutant COMP and an interaction between mutant COMP and type II procollagen are initiating events in the assembly of matrix in the rER, possibly explaining why the material is not readily cleared from the rER. Altogether, these data suggest that mutant COMP initiates and perhaps catalyzes premature intracellular matrix assembly. PMID:17200202

  18. Sigma-1 receptors (sigma(1) binding sites) form raft-like microdomains and target lipid droplets on the endoplasmic reticulum: roles in endoplasmic reticulum lipid compartmentalization and export.

    PubMed

    Hayashi, Teruo; Su, Tsung-Ping

    2003-08-01

    The brain sigma-1 receptors can bind neurosteroids and psychotropic drugs, including neuroleptics and cocaine and are implicated in schizophrenia, depression, and drug dependence. In this study, we found that sigma-1 receptors specifically target lipid storage sites (lipid droplets) on the endoplasmic reticulum by forming a distinct class of lipid microdomains. Both endogenously expressing sigma-1 receptors and transfected C-terminally enhanced yellow fluorescent protein (EYFP)-tagged sigma-1 receptors (Sig-1R-EYFP) target unique "ring-like" structures associated with endoplasmic reticulum reticular networks in NG108-15 cells. The ring-like structures contain neutral lipids and are enlarged by the oleate treatment, indicating that they are endoplasmic reticulum-associated lipid droplets (ER-LDs). sigma-1 receptors colocalize with caveolin-2, a cholesterol-binding protein in lipid rafts on the ER-LDs, but not with adipocyte differentiation-related protein (ADRP), a cytosolic lipid droplet (c-LD)-specific protein. When the double-arginine ER retention signal on the N terminus of sigma-1 receptors is truncated, sigma-1 receptors no longer exist on ER-LDs, but predominantly target c-LDs, which contain ADRP. sigma-1 receptors on ER-LDs form detergent-resistant raft-like lipid microdomains, the buoyancy of which is different from that of plasma membrane lipid rafts. (+)-Pentazocine causes sigma-1 receptors to disappear from the microdomains. N-Terminally EYFP-tagged sigma-1 receptors (EYFP-Sig-1R) failed to target ER-LDs. EYFP-Sig-1R-transfected cells showed an unrestricted distribution of neutral lipids all over the endoplasmic reticulum network, decreases in c-LDs and cholesterol in plasma membranes, and the bulbous aggregation of endoplasmic reticulum. Thus, sigma-1 receptors are unique endoplasmic reticulum proteins that regulate the compartmentalization of lipids on the endoplasmic reticulum and their export from the endoplasmic reticulum to plasma membrane and c-LDs.

  19. Generating Smooth Motions For Robotic Manipulators

    NASA Technical Reports Server (NTRS)

    Bejczy, Antal K.; Szakaly, Zoltan F.

    1993-01-01

    In improved method for generating trajectory of robotic manipulator, each straight-line segment of trajectory composed of constant-velocity main portion sandwiched between smooth acceleration at start and smooth deceleration at finish. Algorithm implementing method computes velocity in each accelerating portion as sinusoidal function of position along line. This motion chosen for two reasons: closely approximates motion of human hand along straight-line trajectory, and provides very smooth transitions between constant-velocity portion and accelerated and decelerational end portions.

  20. Smooth GERBS, orthogonal systems and energy minimization

    NASA Astrophysics Data System (ADS)

    Dechevsky, Lubomir T.; Zanaty, Peter

    2013-12-01

    New results are obtained in three mutually related directions of the rapidly developing theory of generalized expo-rational B-splines (GERBS) [7, 6]: closed-form computability of C∞-smooth GERBS in terms of elementary and special functions, Hermite interpolation and least-squares best approximation via smooth GERBS, energy minimizing properties of smooth GERBS similar to those of the classical cubic polynomial B-splines.

  1. Smooth GERBS, orthogonal systems and energy minimization

    SciTech Connect

    Dechevsky, Lubomir T. E-mail: pza@hin.no; Zanaty, Peter E-mail: pza@hin.no

    2013-12-18

    New results are obtained in three mutually related directions of the rapidly developing theory of generalized expo-rational B-splines (GERBS) [7, 6]: closed-form computability of C{sup ∞}-smooth GERBS in terms of elementary and special functions, Hermite interpolation and least-squares best approximation via smooth GERBS, energy minimizing properties of smooth GERBS similar to those of the classical cubic polynomial B-splines.

  2. Nongenomic STAT5-dependent effects on Golgi apparatus and endoplasmic reticulum structure and function.

    PubMed

    Lee, Jason E; Yang, Yang-Ming; Liang, Feng-Xia; Gough, Daniel J; Levy, David E; Sehgal, Pravin B

    2012-03-01

    We report unexpected nongenomic functions of signal transducer and activator of transcription (STAT) 5 species in the cytoplasm aimed at preserving the structure and function of the Golgi apparatus and rough endoplasmic reticulum (ER) in vascular cells. Immunoimaging and green fluorescent protein-tagged-STAT5a protein localization studies showed the constitutive association of nonphosphorylated STAT5a, and to a lesser extent STAT5b, with the Golgi apparatus and of STAT5a with centrosomes in human pulmonary arterial endothelial and smooth muscle cells. Acute knockdown of STAT5a/b species using small interfering RNAs (siRNAs), including in the presence of an mRNA synthesis inhibitor (5,6-dichloro-1-β-d-ribofuranosylbenzimidazole), produced a dramatic phenotype within 1 day, consisting of dilatation and fragmentation of Golgi cisternae, a marked tubule-to-cyst change in the ER, increased accumulation of reticulon-4 (RTN4)/Nogo-B and atlastin-3 (ATL3) at cyst-zone boundaries, cystic separation of the outer and inner nuclear membranes, accompanied by scalloped/lunate distortion of the nucleus, with accumulation of RTN4 on convex sides of distorted nuclei. These cells showed inhibition of vesicular stomatitis virus G protein glycoprotein trafficking, mitochondrial fragmentation, and reduced mitochondrial function. STAT5a/b(-/-) mouse embryo fibroblasts also showed altered ER/Golgi dynamics. RTN4 knockdown using siRNA did not affect development of the cystic phenotype; ATL3 siRNA led to effacement of cyst-zone boundaries. In magnetic-bead cross-immunopanning assays, ATL3 bound both STAT5a and STAT5b. Remarkably, this novel cystic ER/lunate nucleus phenotype was characteristic of vascular cells in arterial lesions of idiopathic pulmonary hypertension, an unrelentingly fatal human disease. These data provide evidence of a STAT-family protein regulating the structure of a cytoplasmic organelle and implicate this mechanism in the pathogenesis of a human disease.

  3. Role of Endoplasmic Reticulum Stress in Epithelial–Mesenchymal Transition of Alveolar Epithelial Cells

    PubMed Central

    Zhong, Qian; Zhou, Beiyun; Ann, David K.; Minoo, Parviz; Liu, Yixin; Banfalvi, Agnes; Krishnaveni, Manda S.; Dubourd, Mickael; Demaio, Lucas; Willis, Brigham C.; Kim, Kwang-Jin; duBois, Roland M.; Crandall, Edward D.; Beers, Michael F.

    2011-01-01

    Endoplasmic reticulum (ER) stress has been implicated in alveolar epithelial type II (AT2) cell apoptosis in idiopathic pulmonary fibrosis. We hypothesized that ER stress (either chemically induced or due to accumulation of misfolded proteins) is also associated with epithelial–mesenchymal transition (EMT) in alveolar epithelial cells (AECs). ER stress inducers, thapsigargin (TG) or tunicamycin (TN), increased expression of ER chaperone, Grp78, and spliced X-box binding protein 1, decreased epithelial markers, E-cadherin and zonula occludens–1 (ZO-1), increased the myofibroblast marker, α–smooth muscle actin (α-SMA), and induced fibroblast-like morphology in both primary AECs and the AT2 cell line, RLE-6TN, consistent with EMT. Overexpression of the surfactant protein (SP)–C BRICHOS mutant SP-CΔExon4 in A549 cells increased Grp78 and α-SMA and disrupted ZO-1 distribution, and, in primary AECs, SP-CΔExon4 induced fibroblastic-like morphology, decreased ZO-1 and E-cadherin and increased α-SMA, mechanistically linking ER stress associated with mutant SP to fibrosis through EMT. Whereas EMT was evident at lower concentrations of TG or TN, higher concentrations caused apoptosis. The Src inhibitor, 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4]pyramidine) (PP2), abrogated EMT associated with TN or TG in primary AECs, whereas overexpression of SP-CΔExon4 increased Src phosphorylation, suggesting a common mechanism. Furthermore, increased Grp78 immunoreactivity was observed in AT2 cells of mice after bleomycin injury, supporting a role for ER stress in epithelial abnormalities in fibrosis in vivo. These results demonstrate that ER stress induces EMT in AECs, at least in part through Src-dependent pathways, suggesting a novel role for ER stress in fibroblast accumulation in pulmonary fibrosis. PMID:21169555

  4. Trimeric intracellular cation channels and sarcoplasmic/endoplasmic reticulum calcium homeostasis.

    PubMed

    Zhou, Xinyu; Lin, Peihui; Yamazaki, Daiju; Park, Ki Ho; Komazaki, Shinji; Chen, S R Wayne; Takeshima, Hiroshi; Ma, Jianjie

    2014-02-14

    Trimeric intracellular cation channels (TRIC) represents a novel class of trimeric intracellular cation channels. Two TRIC isoforms have been identified in both the human and the mouse genomes: TRIC-A, a subtype predominantly expressed in the sarcoplasmic reticulum (SR) of muscle cells, and TRIC-B, a ubiquitous subtype expressed in the endoplasmic reticulum (ER) of all tissues. Genetic ablation of either TRIC-A or TRIC-B leads to compromised K(+) permeation and Ca(2+) release across the SR/ER membrane, supporting the hypothesis that TRIC channels provide a counter balancing K(+) flux that reduces SR/ER membrane depolarization for maintenance of the electrochemical gradient that drives SR/ER Ca(2+) release. TRIC-A and TRIC-B seem to have differential functions in Ca(2+) signaling in excitable and nonexcitable cells. Tric-a(-/-) mice display defective Ca(2+) sparks and spontaneous transient outward currents in arterial smooth muscle and develop hypertension, in addition to skeletal muscle dysfunction. Knockout of TRIC-B results in abnormal IP3 receptor-mediated Ca(2+) release in airway epithelial cells, respiratory defects, and neonatal lethality. Double knockout mice lacking both TRIC-A and TRIC-B show embryonic lethality as a result of cardiac arrest. Such an aggravated lethality indicates that TRIC-A and TRIC-B share complementary physiological functions in Ca(2+) signaling in embryonic cardiomyocytes. Tric-a(-/-) and Tric-b(+/-) mice are viable and susceptible to stress-induced heart failure. Recent evidence suggests that TRIC-A directly modulates the function of the cardiac ryanodine receptor 2 Ca(2+) release channel, which in turn controls store-overload-induced Ca(2+) release from the SR. Thus, the TRIC channels, in addition to providing a countercurrent for SR/ER Ca(2+) release, may also function as accessory proteins that directly modulate the ryanodine receptor/IP3 receptor channel functions.

  5. Uric acid-induced endoplasmic reticulum stress triggers phenotypic change in rat glomerular mesangial cells.

    PubMed

    Li, Shasha; Zhao, Fei; Cheng, Shaoli; Wang, Xinyang; Hao, Yaning

    2013-10-01

    The aim of this study was to explore the contribution and the mechanism of uric acid (UA) to phenotypic change in rat glomerular mesangial cells. Rat glomerular mesangial cells (HBZY-1) were exposed to UA (0.05 mmol/L to 0.4 mmol/L) for 24 h to 48 h. Subsequently, 4-phenyl butyric acid (4-PBA) (5 mg/dL) was added and 48 h incubation was performed. HBZY-1 cells exposed to UA (0.4 mmol/L) were incubated for 48 h. After incubation, the cells were examined under an inverted microscope and transmission electron microscope to observe their morphologies and the expressions of α-smooth muscle actin (α-SMA), transforming growth factor-β1 (TGF-β1), fibronectin (FN), glucose regulated protein 78 (GRP78), and the protein disulfide isomerase (PDI) proteins and mRNA in the HBZY-1 cells were measured by Western blot and reversed transcription-polymerase chain reaction. HBZY-1 cultured in UA showed evident morphological changes under transmission electron microscopy. The soluble UA stimulated the upregulation of the α-SMA, TGF-β1 and FN mRNA and proteins in a concentration- and time-dependent manner. UA-induced endoplasmic reticulum (ER) stress, as evidenced by the upregulation of the mRNA and protein expressions of GRP78 and PDI. However, the upregulation was reverted by 4-PBA, an inhibitor of ER stress. Uric acid induces phenotypic change in HBZY-1 cells. ER stress plays a central role in UA-induced phenotypic transformation in vitro. 4-PBA may be beneficial in attenuating UA-induced glomerular injury. © 2013 The Authors. Nephrology © 2013 Asian Pacific Society of Nephrology.

  6. 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.

  7. 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

  8. From endoplasmic reticulum to mitochondria: absence of the Arabidopsis ATP antiporter endoplasmic Reticulum Adenylate Transporter1 perturbs photorespiration.

    PubMed

    Hoffmann, Christiane; Plocharski, Bartolome; Haferkamp, Ilka; Leroch, Michaela; Ewald, Ralph; Bauwe, Hermann; Riemer, Jan; Herrmann, Johannes M; Neuhaus, H Ekkehard

    2013-07-01

    The carrier Endoplasmic Reticulum Adenylate Transporter1 (ER-ANT1) resides in the endoplasmic reticulum (ER) membrane and acts as an ATP/ADP antiporter. Mutant plants lacking ER-ANT1 exhibit a dwarf phenotype and their seeds contain reduced protein and lipid contents. In this study, we describe a further surprising metabolic peculiarity of the er-ant1 mutants. Interestingly, Gly levels in leaves are immensely enhanced (26×) when compared with that of wild-type plants. Gly accumulation is caused by significantly decreased mitochondrial glycine decarboxylase (GDC) activity. Reduced GDC activity in mutant plants was attributed to oxidative posttranslational protein modification induced by elevated levels of reactive oxygen species (ROS). GDC activity is crucial for photorespiration; accordingly, morphological and physiological defects in er-ant1 plants were nearly completely abolished by application of high environmental CO(2) concentrations. The latter observation demonstrates that the absence of ER-ANT1 activity mainly affects photorespiration (maybe solely GDC), whereas basic cellular metabolism remains largely unchanged. Since ER-ANT1 homologs are restricted to higher plants, it is tempting to speculate that this carrier fulfils a plant-specific function directly or indirectly controlling cellular ROS production. The observation that ER-ANT1 activity is associated with cellular ROS levels reveals an unexpected and critical physiological connection between the ER and other organelles in plants.

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

    PubMed

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

    2014-07-01

    Spinal and bulbar muscular atrophy is an X-linked degenerative motor neuron disease caused by an abnormal expansion in the polyglutamine encoding CAG repeat of the androgen receptor gene. There is evidence implicating endoplasmic reticulum stress in the development and progression of neurodegenerative disease, including polyglutamine disorders such as Huntington's disease and in motor neuron disease, where cellular stress disrupts functioning of the endoplasmic reticulum, leading to induction of the unfolded protein response. We examined whether endoplasmic reticulum stress is also involved in the pathogenesis of spinal and bulbar muscular atrophy. Spinal and bulbar muscular atrophy mice that carry 100 pathogenic polyglutamine repeats in the androgen receptor, and develop a late-onset neuromuscular phenotype with motor neuron degeneration, were studied. We observed a disturbance in endoplasmic reticulum-associated calcium homeostasis in cultured embryonic motor neurons from spinal and bulbar muscular atrophy mice, which was accompanied by increased endoplasmic reticulum stress. Furthermore, pharmacological inhibition of endoplasmic reticulum stress reduced the endoplasmic reticulum-associated cell death pathway. Examination of spinal cord motor neurons of pathogenic mice at different disease stages revealed elevated expression of markers for endoplasmic reticulum stress, confirming an increase in this stress response in vivo. Importantly, the most significant increase was detected presymptomatically, suggesting that endoplasmic reticulum stress may play an early and possibly causal role in disease pathogenesis. Our results therefore indicate that the endoplasmic reticulum stress pathway could potentially be a therapeutic target for spinal and bulbar muscular atrophy and related polyglutamine diseases. © The Author (2014). Published by Oxford University Press on behalf of the Guarantors of Brain.

  10. Functional role of stromal interaction molecule 1 (STIM1) in vascular smooth muscle cells

    SciTech Connect

    Takahashi, Yoichiro; Watanabe, Hiroyuki; Murakami, Manabu; Ono, Kyoichi; Munehisa, Yoshiko; Koyama, Takashi; Nobori, Kiyoshi; Iijima, Toshihiko; Ito, Hiroshi

    2007-10-05

    We investigated the functional role of STIM1, a Ca{sup 2+} sensor in the endoplasmic reticulum (ER) that regulates store-operated Ca{sup 2+} entry (SOCE), in vascular smooth muscle cells (VSMCs). STIM1 was mainly localized at the ER and plasma membrane. The knockdown of STIM1 expression by small interfering (si) RNA drastically decreased SOCE. In contrast, an EF-hand mutant of STIM1, STIM1{sup E87A}, produced a marked increase in SOCE, which was abolished by co-transfection with siRNA to transient receptor potential canonical 1 (TRPC1). In addition, transfection with siRNA against STIM1 suppressed phosphorylation of cAMP-responsive element binding protein (CREB) and cell growth. These results suggest that STIM1 is an essential component of SOCE and that it is involved in VSMC proliferation.

  11. Suppression of the endoplasmic reticulum calcium pump during zebrafish gastrulation affects left-right asymmetry of the heart and brain.

    PubMed

    Kreiling, Jill A; Balantac, Zaneta L; Crawford, Andrew R; Ren, Yuexin; Toure, Jamal; Zchut, Sigalit; Kochilas, Lazaros; Creton, Robbert

    2008-01-01

    Vertebrate embryos generate striking Ca(2+) patterns, which are unique regulators of dynamic developmental events. In the present study, we used zebrafish embryos as a model system to examine the developmental roles of Ca(2+) during gastrulation. We found that gastrula stage embryos maintain a distinct pattern of cytosolic Ca(2+) along the dorsal-ventral axis, with higher Ca(2+) concentrations in the ventral margin and lower Ca(2+) concentrations in the dorsal margin and dorsal forerunner cells. Suppression of the endoplasmic reticulum Ca(2+) pump with 0.5 microM thapsigargin elevates cytosolic Ca(2+) in all embryonic regions and induces a randomization of laterality in the heart and brain. Affected hearts, visualized in living embryos by a subtractive imaging technique, displayed either a reversal or loss of left-right asymmetry. Brain defects include a left-right reversal of pitx2 expression in the dorsal diencephalon and a left-right reversal of the prominent habenular nucleus in the brain. Embryos are sensitive to inhibition of the endoplasmic reticulum Ca(2+) pump during early and mid gastrulation and lose their sensitivity during late gastrulation and early segmentation. Suppression of the endoplasmic reticulum Ca(2+) pump during gastrulation inhibits expression of no tail (ntl) and left-right dynein related (lrdr) in the dorsal forerunner cells and affects development of Kupffer's vesicle, a ciliated organ that generates a counter-clockwise flow of fluid. Previous studies have shown that Ca(2+) plays a role in Kupffer's vesicle function, influencing ciliary motility and translating the vesicle's counter-clockwise flow into asymmetric patterns of gene expression. The present results suggest that Ca(2+) plays an additional role in the formation of Kupffer's vesicle.

  12. Spatial moving average risk smoothing.

    PubMed

    Botella-Rocamora, P; López-Quílez, A; Martinez-Beneito, M A

    2013-07-10

    This paper introduces spatial moving average risk smoothing (SMARS) as a new way of carrying out disease mapping. This proposal applies the moving average ideas of time series theory to the spatial domain, making use of a spatial moving average process of unknown order to define dependence on the risk of a disease occurring. Correlation of the risks for different locations will be a function of m values (m being unknown), providing a rich class of correlation functions that may be reproduced by SMARS. Moreover, the distance (in terms of neighborhoods) that should be covered for two units to be found to make the correlation of their risks 0 is a quantity to be fitted by the model. This way, we reproduce patterns that range from spatially independent to long-range spatially dependent. We will also show a theoretical study of the correlation structure induced by SMARS, illustrating the wide variety of correlation functions that this proposal is able to reproduce. We will also present three applications of SMARS to both simulated and real datasets. These applications will show SMARS to be a competitive disease mapping model when compared with alternative proposals that have already appeared in the literature. Finally, the application of SMARS to the study of mortality for 21 causes of death in the Comunitat Valenciana will allow us to identify some qualitative differences in the patterns of those diseases. Copyright © 2012 John Wiley & Sons, Ltd.

  13. Smoothed particle hydrodynamics and magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Price, Daniel J.

    2012-02-01

    This paper presents an overview and introduction to smoothed particle hydrodynamics and magnetohydrodynamics in theory and in practice. Firstly, we give a basic grounding in the fundamentals of SPH, showing how the equations of motion and energy can be self-consistently derived from the density estimate. We then show how to interpret these equations using the basic SPH interpolation formulae and highlight the subtle difference in approach between SPH and other particle methods. In doing so, we also critique several 'urban myths' regarding SPH, in particular the idea that one can simply increase the 'neighbour number' more slowly than the total number of particles in order to obtain convergence. We also discuss the origin of numerical instabilities such as the pairing and tensile instabilities. Finally, we give practical advice on how to resolve three of the main issues with SPMHD: removing the tensile instability, formulating dissipative terms for MHD shocks and enforcing the divergence constraint on the particles, and we give the current status of developments in this area. Accompanying the paper is the first public release of the NDSPMHD SPH code, a 1, 2 and 3 dimensional code designed as a testbed for SPH/SPMHD algorithms that can be used to test many of the ideas and used to run all of the numerical examples contained in the paper.

  14. NDSPMHD Smoothed Particle Magnetohydrodynamics Code

    NASA Astrophysics Data System (ADS)

    Price, Daniel J.

    2011-01-01

    This paper presents an overview and introduction to Smoothed Particle Hydrodynamics and Magnetohydrodynamics in theory and in practice. Firstly, we give a basic grounding in the fundamentals of SPH, showing how the equations of motion and energy can be self-consistently derived from the density estimate. We then show how to interpret these equations using the basic SPH interpolation formulae and highlight the subtle difference in approach between SPH and other particle methods. In doing so, we also critique several 'urban myths' regarding SPH, in particular the idea that one can simply increase the 'neighbour number' more slowly than the total number of particles in order to obtain convergence. We also discuss the origin of numerical instabilities such as the pairing and tensile instabilities. Finally, we give practical advice on how to resolve three of the main issues with SPMHD: removing the tensile instability, formulating dissipative terms for MHD shocks and enforcing the divergence constraint on the particles, and we give the current status of developments in this area. Accompanying the paper is the first public release of the NDSPMHD SPH code, a 1, 2 and 3 dimensional code designed as a testbed for SPH/SPMHD algorithms that can be used to test many of the ideas and used to run all of the numerical examples contained in the paper.

  15. Smooth Side of 'Route 66'

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This image was taken by the microscopic imager onboard NASA's Mars Exploration Rover Spirit on sol 99 (April 13, 2004). It is a close-up look at a portion of the rock called 'Route 66,' which was brushed by the rover's rock abrasion tool.

    This image intrigues scientists because it looks very different from the microscopic images taken of other brushed rocks at the Gusev Crater location. The surface of Route 66 is very shiny and specularly reflective, which may indicate a glassy surface, or perhaps a very smooth, discontinuous coating. The unique coating appears mottled and may be multi-layered.

    Other interesting features in this brushed area of Route 66 are the very thin, arc-shaped lines that are visible in the upper left quadrant of the image. An initial hypothesis suggests that these arcs may have been caused by the rock abrasion tool when the instrument made its initial contact with the surface.

    Scientists will use the combined data from the rover's Moessbauer spectrometer and alpha particle X-ray spectrometer along with color versions of this image to try to reach stronger conclusions about what they are seeing and what processes caused the features.

  16. Smooth Passage For The Jetfoil

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The Flying Princess is a Boeing Jetfoil, one of a family of commercial waterjets built by Boeing Marine Systems, a division of The Boeing Company, Seattle, Washington. The new Jetfoil offers a number of advantages over earlier hydrofoils, a major one being a smooth ride in rough waters. NASA technology contributed to jolt-free passenger comfort. Hydrofoils skim the surface at speeds considerably greater than those of conventional ships because there is little friction between hull and water. Hulls are raised above the water by the lift of the foils, which resemble and function like an airplane wing. The foils are attached to the hull by rigid struts, which ordinarily cause a vessel operating in coastal seas to follow the contour of the waves. In wind-whipped waters, this makes for a rough ride. Seeking to increase passenger acceptance, Boeing Marine System engineers looked for ways to improve rough-water ride quality. Langley Research Center conducts continuing ride quality research. Initially, it was aimed at improving aircraft ride; it was later expanded to include all modes of transportation. Research includes studies of vibration, acceleration, temperature, humidity, passenger seats and posture, and the psychological aspects of passenger reaction to vehicle ride. As part of the program, Langley developed instrumentation, ride quality models and methods of data analysis.

  17. Smooth horizons and quantum ripples

    NASA Astrophysics Data System (ADS)

    Golovnev, Alexey

    2015-05-01

    Black holes are unique objects which allow for meaningful theoretical studies of strong gravity and even quantum gravity effects. An infalling and a distant observer would have very different views on the structure of the world. However, a careful analysis has shown that it entails no genuine contradictions for physics, and the paradigm of observer complementarity has been coined. Recently this picture was put into doubt. In particular, it was argued that in old black holes a firewall must form in order to protect the basic principles of quantum mechanics. This AMPS paradox has already been discussed in a vast number of papers with different attitudes and conclusions. Here we want to argue that a possible source of confusion is the neglect of quantum gravity effects. Contrary to widespread perception, it does not necessarily mean that effective field theory is inapplicable in rather smooth neighbourhoods of large black hole horizons. The real offender might be an attempt to consistently use it over the huge distances from the near-horizon zone of old black holes to the early radiation. We give simple estimates to support this viewpoint and show how the Page time and (somewhat more speculative) scrambling time do appear.

  18. 7 CFR 51.1870 - Fairly smooth.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... Standards for Fresh Tomatoes 1 Definitions § 51.1870 Fairly smooth. Fairly smooth means that the tomato...

  19. Thermal smoothing of rough surfaces in vacuo

    NASA Technical Reports Server (NTRS)

    Wahl, G.

    1986-01-01

    The derivation of equations governing the smoothing of rough surfaces, based on Mullins' (1957, 1960, and 1963) theories of thermal grooving and of capillarity-governed solid surface morphology is presented. As an example, the smoothing of a one-dimensional sine-shaped surface is discussed.

  20. Myosin filament structure in vertebrate smooth muscle

    PubMed Central

    1996-01-01

    The in vivo structure of the myosin filaments in vertebrate smooth muscle is unknown. Evidence from purified smooth muscle myosin and from some studies of intact smooth muscle suggests that they may have a nonhelical, side-polar arrangement of crossbridges. However, the bipolar, helical structure characteristic of myosin filaments in striated muscle has not been disproved for smooth muscle. We have used EM to investigate this question in a functionally diverse group of smooth muscles (from the vascular, gastrointestinal, reproductive, and visual systems) from mammalian, amphibian, and avian species. Intact muscle under physiological conditions, rapidly frozen and then freeze substituted, shows many myosin filaments with a square backbone in transverse profile. Transverse sections of fixed, chemically skinned muscles also show square backbones and, in addition, reveal projections (crossbridges) on only two opposite sides of the square. Filaments gently isolated from skinned smooth muscles and observed by negative staining show crossbridges with a 14.5-nm repeat projecting in opposite directions on opposite sides of the filament. Such filaments subjected to low ionic strength conditions show bare filament ends and an antiparallel arrangement of myosin tails along the length of the filament. All of these observations are consistent with a side-polar structure and argue against a bipolar, helical crossbridge arrangement. We conclude that myosin filaments in all smooth muscles, regardless of function, are likely to be side-polar. Such a structure could be an important factor in the ability of smooth muscles to contract by large amounts. PMID:8698822

  1. Leiomodin and tropomodulin in smooth muscle

    NASA Technical Reports Server (NTRS)

    Conley, C. A.

    2001-01-01

    Evidence is accumulating to suggest that actin filament remodeling is critical for smooth muscle contraction, which implicates actin filament ends as important sites for regulation of contraction. Tropomodulin (Tmod) and smooth muscle leiomodin (SM-Lmod) have been found in many tissues containing smooth muscle by protein immunoblot and immunofluorescence microscopy. Both proteins cofractionate with tropomyosin in the Triton-insoluble cytoskeleton of rabbit stomach smooth muscle and are solubilized by high salt. SM-Lmod binds muscle tropomyosin, a biochemical activity characteristic of Tmod proteins. SM-Lmod staining is present along the length of actin filaments in rat intestinal smooth muscle, while Tmod stains in a punctate pattern distinct from that of actin filaments or the dense body marker alpha-actinin. After smooth muscle is hypercontracted by treatment with 10 mM Ca(2+), both SM-Lmod and Tmod are found near alpha-actinin at the periphery of actin-rich contraction bands. These data suggest that SM-Lmod is a novel component of the smooth muscle actin cytoskeleton and, furthermore, that the pointed ends of actin filaments in smooth muscle may be capped by Tmod in localized clusters.

  2. Leiomodin and tropomodulin in smooth muscle

    NASA Technical Reports Server (NTRS)

    Conley, C. A.

    2001-01-01

    Evidence is accumulating to suggest that actin filament remodeling is critical for smooth muscle contraction, which implicates actin filament ends as important sites for regulation of contraction. Tropomodulin (Tmod) and smooth muscle leiomodin (SM-Lmod) have been found in many tissues containing smooth muscle by protein immunoblot and immunofluorescence microscopy. Both proteins cofractionate with tropomyosin in the Triton-insoluble cytoskeleton of rabbit stomach smooth muscle and are solubilized by high salt. SM-Lmod binds muscle tropomyosin, a biochemical activity characteristic of Tmod proteins. SM-Lmod staining is present along the length of actin filaments in rat intestinal smooth muscle, while Tmod stains in a punctate pattern distinct from that of actin filaments or the dense body marker alpha-actinin. After smooth muscle is hypercontracted by treatment with 10 mM Ca(2+), both SM-Lmod and Tmod are found near alpha-actinin at the periphery of actin-rich contraction bands. These data suggest that SM-Lmod is a novel component of the smooth muscle actin cytoskeleton and, furthermore, that the pointed ends of actin filaments in smooth muscle may be capped by Tmod in localized clusters.

  3. Fourier smoothing of digital photographic spectra

    NASA Astrophysics Data System (ADS)

    Anupama, G. C.

    1990-03-01

    Fourier methods of smoothing one-dimensional data are discussed with particular reference to digital photographic spectra. Data smoothed using lowpass filters with different cut-off frequencies are intercompared. A method to scale densities in order to remove the dependence of grain noise on density is described. Optimal filtering technique which models signal and noise in Fourier domain is also explained.

  4. Smoothing the output from a DAC

    NASA Technical Reports Server (NTRS)

    Wagner, C.

    1980-01-01

    Circuit smooths stepped waveform from analog-to-digital converter without appreciable phase shift between stepped input signal and smoothed output signal and without any effect from stepping rate. Waveform produced is suitable for driving controls used in manufacturing processes, aerospace systems, and automobiles.

  5. Smoothing splines: Regression, derivatives and deconvolution

    NASA Technical Reports Server (NTRS)

    Rice, J.; Rosenblatt, M.

    1982-01-01

    The statistical properties of a cubic smoothing spline and its derivative are analyzed. It is shown that unless unnatural boundary conditions hold, the integrated squared bias is dominated by local effects near the boundary. Similar effects are shown to occur in the regularized solution of a translation-kernel intergral equation. These results are derived by developing a Fourier representation for a smoothing spline.

  6. Endoplasmic Reticulum Stress Sensing in the Unfolded Protein Response

    PubMed Central

    Gardner, Brooke M.; Pincus, David; Gotthardt, Katja; Gallagher, Ciara M.; Walter, Peter

    2013-01-01

    Secretory and transmembrane proteins enter the endoplasmic reticulum (ER) as unfolded proteins and exit as either folded proteins in transit to their target organelles or as misfolded proteins targeted for degradation. The unfolded protein response (UPR) maintains the protein-folding homeostasis within the ER, ensuring that the protein-folding capacity of the ER meets the load of client proteins. Activation of the UPR depends on three ER stress sensor proteins, Ire1, PERK, and ATF6. Although the consequences of activation are well understood, how these sensors detect ER stress remains unclear. Recent evidence suggests that yeast Ire1 directly binds to unfolded proteins, which induces its oligomerization and activation. BiP dissociation from Ire1 regulates this oligomeric equilibrium, ultimately modulating Ire1’s sensitivity and duration of activation. The mechanistic principles of ER stress sensing are the focus of this review. PMID:23388626

  7. Co-chaperones of the mammalian endoplasmic reticulum.

    PubMed

    Melnyk, Armin; Rieger, Heiko; Zimmermann, Richard

    2015-01-01

    In mammalian cells, the rough endoplasmic reticulum or ER plays a central role in the biogenesis of most extracellular plus many organellar proteins and in cellular calcium homeostasis. Therefore, this organelle comprises molecular chaperones that are involved in import, folding/assembly, export, and degradation of polypeptides in millimolar concentrations. In addition, there are calcium channels/pumps and signal transduction components present in the ER membrane that affect and are affected by these processes. The ER lumenal Hsp70, termed immunoglobulin-heavy chain binding protein or BiP, is the central player in all these activities and involves up to seven different co-chaperones, i.e. ER-membrane integrated as well as ER-lumenal Hsp40s, which are termed ERj or ERdj, and two nucleotide exchange factors.

  8. 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

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

    PubMed

    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

    2013-07-18

    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 improved staining and automated ultrathin 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.

  10. Endoplasmic Reticulum Calcium, Stress and Cell-to-Cell Adhesion

    PubMed Central

    Mauro, Theodora

    2014-01-01

    Darier's Disease (DD) is caused by mutations in the endoplasmic reticulum (ER) Ca2+ ATPase ATP2A2 (protein SERCA2). Current treatment modalities are ineffective for many patients. This report shows that impaired SERCA2 function, both in DD keratinocytes and in normal keratinocytes treated with the SERCA2-inhibitor thapsigargin, depletes ER Ca2+ stores, leading to constitutive ER stress and increased sensitivity to ER stressors. ER stress, in turn, leads to abnormal cell-to-cell adhesion via impaired redistribution of desmoplakin, desmoglein 3, desmocollin 3 and E-cadherin to the plasma membrane. This report illustrates how ER Ca2+ depletion and the resulting ER stress are central to the pathogenesis of the disease. Additionally, the authors introduce a possible new therapeutic agent, Miglustat. PMID:24924761

  11. WLS retrograde transport to the endoplasmic reticulum during Wnt secretion.

    PubMed

    Yu, Jia; Chia, Joanne; Canning, Claire Ann; Jones, C Michael; Bard, Frédéric A; Virshup, David M

    2014-05-12

    Wnts are transported to the cell surface by the integral membrane protein WLS (also known as Wntless, Evi, and GPR177). Previous studies of WLS trafficking have emphasized WLS movement from the Golgi to the plasma membrane (PM) and then back to the Golgi via retromer-mediated endocytic recycling. We find that endogenous WLS binds Wnts in the endoplasmic reticulum (ER), cycles to the PM, and then returns to the ER through the Golgi. We identify an ER-targeting sequence at the carboxyl terminus of native WLS that is critical for ER retrograde recycling and contributes to Wnt secretory function. Golgi-to-ER recycling of WLS requires the COPI regulator ARF as well as ERGIC2, an ER-Golgi intermediate compartment protein that is also required for the retrograde trafficking of the KDEL receptor and certain toxins. ERGIC2 is required for efficient Wnt secretion. ER retrieval is an integral part of the WLS transport cycle.

  12. Trichoplein/mitostatin regulates endoplasmic reticulum-mitochondria juxtaposition.

    PubMed

    Cerqua, Cristina; Anesti, Vassiliki; Pyakurel, Aswin; Liu, Dan; Naon, Deborah; Wiche, Gerhard; Baffa, Raffaele; Dimmer, Kai S; Scorrano, Luca

    2010-11-01

    Trichoplein/mitostatin (TpMs) is a keratin-binding protein that partly colocalizes with mitochondria and is often downregulated in epithelial cancers, but its function remains unclear. In this study, we report that TpMs regulates the tethering between mitochondria and endoplasmic reticulum (ER) in a Mitofusin 2 (Mfn2)-dependent manner. Subcellular fractionation and immunostaining show that TpMs is present at the interface between mitochondria and ER. The expression of TpMs leads to mitochondrial fragmentation and loosens tethering with ER, whereas its silencing has opposite effects. Functionally, the reduced tethering by TpMs inhibits apoptosis by Ca(2+)-dependent stimuli that require ER-mitochondria juxtaposition. Biochemical and genetic evidence support a model in which TpMs requires Mfn2 to modulate mitochondrial shape and tethering. Thus, TpMs is a new regulator of mitochondria-ER juxtaposition.

  13. Interplay of endoplasmic reticulum stress and autophagy in neurodegenerative disorders

    PubMed Central

    Cai, Yu; Arikkath, Jyothi; Yang, Lu; Guo, Ming-Lei; Periyasamy, Palsamy; Buch, Shilpa

    2016-01-01

    ABSTRACT The common underlying feature of most neurodegenerative diseases such as Alzheimer disease (AD), prion diseases, Parkinson disease (PD), and amyotrophic lateral sclerosis (ALS) involves accumulation of misfolded proteins leading to initiation of endoplasmic reticulum (ER) stress and stimulation of the unfolded protein response (UPR). Additionally, ER stress more recently has been implicated in the pathogenesis of HIV-associated neurocognitive disorders (HAND). Autophagy plays an essential role in the clearance of aggregated toxic proteins and degradation of the damaged organelles. There is evidence that autophagy ameliorates ER stress by eliminating accumulated misfolded proteins. Both abnormal UPR and impaired autophagy have been implicated as a causative mechanism in the development of various neurodegenerative diseases. This review highlights recent advances in the field on the role of ER stress and autophagy in AD, prion diseases, PD, ALS and HAND with the involvement of key signaling pathways in these processes and implications for future development of therapeutic strategies. PMID:26902584

  14. Endoplasmic reticulum stress, pancreatic β-cell degeneration, and diabetes.

    PubMed

    Papa, Feroz R

    2012-09-01

    Overwhelming of protein folding in the endoplasmic reticulum (ER)--referred to as "ER stress"--activates a set of intracellular signaling pathways termed the unfolded protein response (UPR). Beneficial outputs of the UPR promote adaptation in cells experiencing manageably low levels of ER stress. However, if ER stress reaches critically high levels, the UPR uses destructive outputs to trigger programmed cell death. Genetic mutations in various UPR components cause inherited syndromes of diabetes mellitus in both rodents and humans, implicating the UPR in the proper functioning and survival of pancreatic islet β cells. Markers of chronically elevated ER stress, terminal UPR signaling, and apoptosis are evident in β cells in these rare disorders; these markers are similarly present in islets of human patients with common forms of diabetes. These findings promise to enhance our molecular understanding of human diabetes significantly and may lead to new and effective therapies.

  15. Trichoplein/mitostatin regulates endoplasmic reticulum–mitochondria juxtaposition

    PubMed Central

    Cerqua, Cristina; Anesti, Vassiliki; Pyakurel, Aswin; Liu, Dan; Naon, Deborah; Wiche, Gerhard; Baffa, Raffaele; Dimmer, Kai S; Scorrano, Luca

    2010-01-01

    Trichoplein/mitostatin (TpMs) is a keratin-binding protein that partly colocalizes with mitochondria and is often downregulated in epithelial cancers, but its function remains unclear. In this study, we report that TpMs regulates the tethering between mitochondria and endoplasmic reticulum (ER) in a Mitofusin 2 (Mfn2)-dependent manner. Subcellular fractionation and immunostaining show that TpMs is present at the interface between mitochondria and ER. The expression of TpMs leads to mitochondrial fragmentation and loosens tethering with ER, whereas its silencing has opposite effects. Functionally, the reduced tethering by TpMs inhibits apoptosis by Ca2+-dependent stimuli that require ER–mitochondria juxtaposition. Biochemical and genetic evidence support a model in which TpMs requires Mfn2 to modulate mitochondrial shape and tethering. Thus, TpMs is a new regulator of mitochondria–ER juxtaposition. PMID:20930847

  16. Arresting a Torsin ATPase Reshapes the Endoplasmic Reticulum*

    PubMed Central

    Rose, April E.; Zhao, Chenguang; Turner, Elizabeth M.; Steyer, Anna M.; Schlieker, Christian

    2014-01-01

    Torsins are membrane-tethered AAA+ ATPases residing in the nuclear envelope (NE) and endoplasmic reticulum (ER). Here, we show that the induction of a conditional, dominant-negative TorsinB variant provokes a profound reorganization of the endomembrane system into foci containing double membrane structures that are derived from the ER. These double-membrane sinusoidal structures are formed by compressing the ER lumen to a constant width of 15 nm, and are highly enriched in the ATPase activator LULL1. Further, we define an important role for a highly conserved aromatic motif at the C terminus of Torsins. Mutations in this motif perturb LULL1 binding, reduce ATPase activity, and profoundly limit the induction of sinusoidal structures. PMID:24275647

  17. Novel ubiquitin-dependent quality control in the endoplasmic reticulum.

    PubMed

    Feldman, M; van der Goot, F Gisou

    2009-08-01

    Proteins of the endomembrane system undergo assisted folding in the endoplasmic reticulum (ER), then quality-control and, if misfolded, ER-associated degradation (ERAD). Recent findings on the biogenesis of a type-I membrane protein (an LRP6 mutant) lead us to hypothesize the existence of a novel mechanism promoting folding of membrane proteins from the cytosolic side of the ER. The proposed folding mechanism involves cycles of chaperone binding through mono-ubiquitylation and de-ubiquitylation, followed eventually by poly-ubiquitylation and ERAD. This suggests a novel dual role for ubiquitylation in the ER - dependent on the type of ubiquitin chains involved - in folding and in degradation, and highlights the potential importance of de-ubiquitylating enzymes.

  18. Endoplasmic reticulum stress in diabetes: New insights of clinical relevance.

    PubMed

    Balasubramanyam, Muthuswamy; Lenin, Raji; Monickaraj, Finny

    2010-04-01

    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. Accumulating evidence suggests that ER stress plays a role in the pathogenesis of diabetes, contributing to pancreatic β-cell loss and insulin resistance. ER stress may also link obesity, inflammation and insulin resistance in type 2 diabetes. In this review, we address the transition from physiology to pathology, namely how and why the physiological UPR evolves to a proapoptotic ER stress response in diabetes and its complications. Special attention was given to elucidate how ER stress could explain some of the 'clinical paradoxes' such as secondary sulfonylurea failure, initial worsening of retinopathy during tight glycemic control, insulin resistance induced by protease inhibitors and other clinically relevant observations.

  19. Assembly of MHC class I molecules within the endoplasmic reticulum.

    PubMed

    Zhang, Yinan; Williams, David B

    2006-01-01

    MHC class I molecules bind cytosolically derived peptides within the endoplasmic reticulum (ER) and present them at the cell surface to cytotoxic T cells. A major focus of our laboratory has been to understand the functions of the diverse proteins involved in the intracellular assembly of MHC class I molecules. These include the molecular chaperones calnexin and calreticulin, which enhance the proper folding and subunit assembly of class I molecules and also retain assembly intermediates within the ER; ERp57, a thiol oxidoreductase that promotes heavy chain disulfide formation and proper assembly of the peptide loading complex; tapasin, which recruits class I molecules to the TAP peptide transporter and enhances the loading of high affinity peptide ligands; and Bap31, which is involved in clustering assembled class I molecules at ER exit sites for export along the secretory pathway. This review describes our contributions to elucidating the functions of these proteins; the combined effort of many dedicated students and postdoctoral fellows.

  20. Stress Responses from the Endoplasmic Reticulum in Cancer

    PubMed Central

    Kato, Hironori; Nishitoh, Hideki

    2015-01-01

    The endoplasmic reticulum (ER) is a dynamic organelle that is essential for multiple cellular functions. During cellular stress conditions, including nutrient deprivation and dysregulation of protein synthesis, unfolded/misfolded proteins accumulate in the ER lumen, resulting in activation of the unfolded protein response (UPR). The UPR also contributes to the regulation of various intracellular signaling pathways such as calcium signaling and lipid signaling. More recently, the mitochondria-associated ER membrane (MAM), which is a site of close contact between the ER and mitochondria, has been shown to function as a platform for various intracellular stress responses including apoptotic signaling, inflammatory signaling, the autophagic response, and the UPR. Interestingly, in cancer, these signaling pathways from the ER are often dysregulated, contributing to cancer cell metabolism. Thus, the signaling pathway from the ER may be a novel therapeutic target for various cancers. In this review, we discuss recent research on the roles of stress responses from the ER, including the MAM. PMID:25941664

  1. Auxin deprivation induces a developmental switch in maize somatic embryogenesis involving redistribution of microtubules and actin filaments from endoplasmic to cortical cytoskeletal arrays.

    PubMed

    Samaj, J; Baluska, F; Pretová, A; Volkmann, D

    2003-06-01

    A developmental switch from non-polar pre-embryogenic units to polarized transition units in maize embryogenic callus is caused by auxin deprivation from the culture medium. This switch is accompanied by cytoskeletal rearrangements in embryogenic cells. An immunofluorescence study revealed prominent endoplasmic microtubules and actin filament meshworks radiating from the nuclear surfaces in pre-embryogenic cells growing on medium supplemented with auxin. On the other hand, parallel-organized cortical microtubules and cortical actin filament networks are inherently associated with polarized embryogenic cells of transition units growing on medium without auxin. These results indicate that fine-tuning of the dynamic equilibrium between endoplasmic and cortical cytoskeletal arrays is important for progress in somatic embryogenesis.

  2. Lunar Smooth Plains Identification and Classification

    NASA Astrophysics Data System (ADS)

    Boyd, A. K.; Robinson, M. S.; Mahanti, P.; Lawrence, S. J.; Spudis, P.; Jolliff, B. L.

    2012-12-01

    Smooth plains are widespread on the Moon and have diverse origins. The maria comprise the majority of the smooth plains and are volcanic in origin. Highland smooth plains are patchy, and tend to fill large craters and basins; their origins have eluded unambiguous classification. Prior to the Apollo 16 mission, many workers thought that highland plains were volcanic, possibly more silicic than the maria. However, as the Apollo 16 samples are mostly impact breccias, the highland smooth plains were re-interpreted basin impact ejecta, most likely from the Imbrium and possibly Orientale basins. Conversely, some known non-mare volcanic units, such as the Apennine Bench Formation, contain light plains. These interpretations do not rule out alternate origins for a subset of highland smooth plains, including impact melt or volcanic origins (effusive or pyroclastic). We developed an algorithm to identify smooth plains using topographic parameters from the WAC Global Lunar Digital Terrain Model (DTM) (GLD100), sampled at 333 m/pixel. We classify the smooth plains using the Clementine UVVIS FeO map and photometrically corrected Lunar Reconnaissance Orbiter Camera (LROC) Wide Angle Camera (WAC) images. Terrain with slopes less than 2° (1 km baseline) and standard deviation of slope less than 0.75° (1 km x 1 km box, n=9) are defined as smooth plains. Highland smooth plains are distinguished from basaltic smooth plains using the following criteria: LROC WAC 643 nm normalized reflectance > 0.056, LROC WAC 321 nm / 415 nm ratio < 0.74, and Clementine FeO < 12 wt.% (excluding Clementine non-coverage areas). The remaining smooth plains are classified as maria and are subdivided into two classes: LROC WAC 321 nm / 415 nm ratio > 0.77 is termed blue maria and a ratio ≤ 0.77 is termed red maria. The automatic classification was limited to the 87% of the Moon covered by photometrically normalized WAC data (60°S to 60°N). The differences between the maria and highland smooth plains

  3. The ATPase cycle of the endoplasmic chaperone Grp94.

    PubMed

    Frey, Stephan; Leskovar, Adriane; Reinstein, Jochen; Buchner, Johannes

    2007-12-07

    Grp94, the Hsp90 paralog of the endoplasmic reticulum, plays a crucial role in protein secretion. Like cytoplasmic Hsp90, Grp94 is regulated by nucleotide binding to its N-terminal domain. However, the question of whether Grp94 hydrolyzes ATP was controversial. This sets Grp94 apart from other members of the Hsp90 family where a slow but specific turnover of ATP has been unambiguously established. In this study we aimed at analyzing the nucleotide binding properties and the potential ATPase activity of Grp94. We show here that Grp94 has an ATPase activity comparable with that of yeast Hsp90 with a k(cat) of 0.36 min(-1) at 25 degrees C. Kinetic and equilibrium constants of the partial reactions of the ATPase cycle were determined using transient kinetic methods. Nucleotide binding appears to be tighter compared with other Hsp90s investigated, with dissociation constants (K(D)) of approximately 4 microm for ADP, ATP, and AMP-PCP. Interestingly, all nucleotides and inhibitors (radicicol, 5'-N-ethylcarboxamidoadenosine) studied here bind with similar rate constants for association (0.2-0.3 x 10(6) M(-1) s(-1)). Furthermore, there is a marked difference from cytosolic Hsp90s in that after binding, the ATP molecule does not seem to become trapped by conformational changes in Grp94. Grp94 stays predominantly in the open state concerning the nucleotide-binding pocket as evidenced by kinetic analyses. Thus, Grp94 shows mechanistically important differences in the interaction with adenosine nucleotides, but the basic hydrolysis reaction seems to be conserved between cytosolic and endoplasmic members of the Hsp90 family.

  4. Maternal obesity alters endoplasmic reticulum homeostasis in offspring pancreas.

    PubMed

    Soeda, Jumpei; Mouralidarane, Angelina; Cordero, Paul; Li, Jiawei; Nguyen, Vi; Carter, Rebeca; Kapur, Sabrina R; Pombo, Joaquim; Poston, Lucilla; Taylor, Paul D; Vinciguerra, Manlio; Oben, Jude A

    2016-06-01

    The prevalence of non-alcoholic fatty pancreas disease (NAFPD) is increasing in parallel with obesity rates. Stress-related alterations in endoplasmic reticulum (ER), such as the unfolded protein response (UPR), are associated with obesity. The aim of this study was to investigate ER imbalance in the pancreas of a mice model of adult and perinatal diet-induced obesity. Twenty female C57BL/6J mice were assigned to control (Con) or obesogenic (Ob) diets prior to and during pregnancy and lactation. Their offspring were weaned onto Con or Ob diets up to 6 months post-partum. Then, after sacrifice, plasma biochemical analyses, gene expression, and protein concentrations were measured in pancreata. Offspring of Ob-fed mice had significantly increased body weight (p < 0.001) and plasma leptin (p < 0.001) and decreased insulin (p < 0.01) levels. Maternal obesogenic diet decreased the total and phosphorylated Eif2α and increased spliced X-box binding protein 1 (XBP1). Pancreatic gene expression of downstream regulators of UPR (EDEM, homocysteine-responsive endoplasmic reticulum-resident (HERP), activating transcription factor 4 (ATF4), and C/EBP homologous protein (CHOP)) and autophagy-related proteins (LC3BI/LC3BII) were differently disrupted by obesogenic feeding in both mothers and offspring (from p < 0.1 to p < 0.001). Maternal obesity and Ob feeding in their offspring alter UPR in NAFPD, with involvement of proapoptotic and autophagy-related markers. Upstream and downstream regulators of PERK, IRE1α, and ATF6 pathways were affected differently following the obesogenic insults.

  5. Polo-like Kinase 1 Regulates Vimentin Phosphorylation at Ser-56 and Contraction in Smooth Muscle.

    PubMed

    Li, Jia; Wang, Ruping; Gannon, Olivia J; Rezey, Alyssa C; Jiang, Sixin; Gerlach, Brennan D; Liao, Guoning; Tang, Dale D

    2016-11-04

    Polo-like kinase 1 (Plk1) is a serine/threonine-protein kinase that has been implicated in mitosis, cytokinesis, and smooth muscle cell proliferation. The role of Plk1 in smooth muscle contraction has not been investigated. Here, stimulation with acetylcholine induced Plk1 phosphorylation at Thr-210 (an indication of Plk1 activation) in smooth muscle. Contractile stimulation also activated Plk1 in live smooth muscle cells as evidenced by changes in fluorescence resonance energy transfer signal of a Plk1 sensor. Moreover, knockdown of Plk1 in smooth muscle attenuated force development. Smooth muscle conditional knock-out of Plk1 also diminished contraction of mouse tracheal rings. Plk1 knockdown inhibited acetylcholine-induced vimentin phosphorylation at Ser-56 without affecting myosin light chain phosphorylation. Expression of T210A Plk1 inhibited the agonist-induced vimentin phosphorylation at Ser-56 and contraction in smooth muscle. However, myosin light chain phosphorylation was not affected by T210A Plk1. Ste20-like kinase (SLK) is a serine/threonine-protein kinase that has been implicated in spindle orientation and microtubule organization during mitosis. In this study knockdown of SLK inhibited Plk1 phosphorylation at Thr-210 and activation. Finally, asthma is characterized by airway hyperresponsiveness, which largely stems from airway smooth muscle hyperreactivity. Here, smooth muscle conditional knock-out of Plk1 attenuated airway resistance and airway smooth muscle hyperreactivity in a murine model of asthma. Taken together, these findings suggest that Plk1 regulates smooth muscle contraction by modulating vimentin phosphorylation at Ser-56. Plk1 activation is regulated by SLK during contractile activation. Plk1 contributes to the pathogenesis of asthma. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  6. Excimer Laser Smoothing of Endothelial Keratoplasty Grafts

    PubMed Central

    Cleary, Catherine; Liu, Ying; Tang, Maolong; Li, Yan; Stoeger, Christopher; Huang, David

    2011-01-01

    Purpose To use excimer laser smoothing passes to reshape DSAEK endothelial grafts, and to evaluate the effect on the donor endothelium. Methods The stromal surface of microkeratome-cut DSAEK grafts was smoothed using excimer laser smoothing passes with masking fluid. Excimer laser hyperopic ablation was used to improve the uniformity of graft thickness within the optical zone. Fourier-domain optical coherence tomography (OCT) was used to measure endothelial graft pachymetry, plan ablations, and evaluate donor contour. Vital dye staining was performed to assess endothelial cell damage. Scanning electron microscopy (SEM) images of stromal surfaces were graded on a 5-point scale by masked observers to evaluate surface roughness. Results Four grafts underwent excimer laser smoothing. Vital dye staining showed no endothelial damage. Microkeratome-cut surfaces treated with laser smoothing (mean grade=2.04) were smoother than non-smoothed microkeratome-cut surfaces (mean grade=4.07, p<0.01), surfaces which underwent dry laser ablation (mean grade=3.63, p<0.01), and manually dissected interfaces (mean grade=4.75, p<0.0001). No difference was observed between stromal beds created by peeling Descemet’s membrane (mean grade=1.64) compared to surfaces produced by microkeratome cutting followed by laser smoothing (mean grade=2.04, p=0.14). One graft underwent combined excimer smoothing and peripheral hyperopic ablation. The centre-periphery thickness difference was 15μm prior to ablation and 4μm afterward. Conclusion Laser smoothing passes can be used to improve the contour and smoothness of DSAEK grafts without damaging donor endothelial cells. Clinical trials are needed to determine whether reshaping donors using excimer laser can deliver improved visual outcomes following DSAEK. PMID:22322485

  7. Pyk2 inhibition promotes contractile differentiation in arterial smooth muscle.

    PubMed

    Grossi, Mario; Bhattachariya, Anirban; Nordström, Ina; Turczyńska, Karolina M; Svensson, Daniel; Albinsson, Sebastian; Nilsson, Bengt-Olof; Hellstrand, Per

    2017-11-01

    Modulation from contractile to synthetic phenotype of vascular smooth muscle cells is a central process in disorders involving compromised integrity of the vascular wall. Phenotype modulation has been shown to include transition from voltage-dependent toward voltage-independent regulation of the intracellular calcium level, and inhibition of non-voltage dependent calcium influx contributes to maintenance of the contractile phenotype. One possible mediator of calcium-dependent signaling is the FAK-family non-receptor protein kinase Pyk2, which is activated by a number of stimuli in a calcium-dependent manner. We used the Pyk2 inhibitor PF-4594755 and Pyk2 siRNA to investigate the role of Pyk2 in phenotype modulation in rat carotid artery smooth muscle cells and in cultured intact arteries. Pyk2 inhibition promoted the expression of smooth muscle markers at the mRNA and protein levels under stimulation by FBS or PDGF-BB and counteracted phenotype shift in cultured intact carotid arteries and balloon injury ex vivo. During long-term (24-96 hr) treatment with PF-4594755, smooth muscle markers increased before cell proliferation was inhibited, correlating with decreased KLF4 expression and differing from effects of MEK inhibition. The Pyk2 inhibitor reduced Orai1 and preserved SERCA2a expression in carotid artery segments in organ culture, and eliminated the inhibitory effect of PDGF stimulation on L-type calcium channel and large-conductance calcium-activated potassium channel expression in carotid cells. Basal intracellular calcium level, calcium wave activity, and store-operated calcium influx were reduced after Pyk2 inhibition of growth-stimulated cells. Pyk2 inhibition may provide an interesting approach for preserving vascular smooth muscle differentiation under pathophysiological conditions. © 2016 Wiley Periodicals, Inc.

  8. Endoplasmic reticulum stress regulates rat mandibular cartilage thinning under compressive mechanical stress.

    PubMed

    Li, Huang; Zhang, Xiang-Yu; Wu, Tuo-Jiang; Cheng, Wei; Liu, Xin; Jiang, Ting-Ting; Wen, Juan; Li, Jie; Ma, Qiao-Ling; Hua, Zi-Chun

    2013-06-21

    Compressive mechanical stress-induced cartilage thinning has been characterized as a key step in the progression of temporomandibular joint diseases, such as osteoarthritis. However, the regulatory mechanisms underlying this loss have not been thoroughly studied. Here, we used an established animal model for loading compressive mechanical stress to induce cartilage thinning in vivo. The mechanically stressed mandibular chondrocytes were then isolated to screen potential candidates using a proteomics approach. A total of 28 proteins were identified that were directly or indirectly associated with endoplasmic reticulum stress, including protein disulfide-isomerase, calreticulin, translationally controlled tumor protein, and peptidyl-prolyl cis/trans-isomerase protein. The altered expression of these candidates was validated at both the mRNA and protein levels. The induction of endoplasmic reticulum stress by mechanical stress loading was confirmed by the activation of endoplasmic reticulum stress markers, the elevation of the cytoplasmic Ca(2+) level, and the expansion of endoplasmic reticulum membranes. More importantly, the use of a selective inhibitor to block endoplasmic reticulum stress in vivo reduced the apoptosis observed at the early stages of mechanical stress loading and inhibited the proliferation observed at the later stages of mechanical stress loading. Accordingly, the use of the inhibitor significantly restored cartilage thinning. Taken together, these results demonstrated that endoplasmic reticulum stress is significantly activated in mechanical stress-induced mandibular cartilage thinning and, more importantly, that endoplasmic reticulum stress inhibition alleviates this loss, suggesting a novel pharmaceutical strategy for the treatment of mechanical stress-induced temporomandibular joint diseases.

  9. SMACK - SMOOTHING FOR AIRCRAFT KINEMATICS

    NASA Technical Reports Server (NTRS)

    Bach, R.

    1994-01-01

    The computer program SMACK (SMoothing for AirCraft Kinematics) is designed to provide flightpath reconstruction of aircraft forces and motions from measurements that are noisy or incomplete. Additionally, SMACK provides a check on instrument accuracy and data consistency. The program can be used to analyze data from flight-test experiments prior to their use in performance, stability and control, or aerodynamic modeling calculations. It can also be used in the analysis of aircraft accidents, where the actual forces and motions may have to be determined from a very limited data set. Application of a state-estimation method for flightpath reconstruction is possible because aircraft forces and motions are related by well-known equations of motion. The task of postflight state estimation is known as a nonlinear, fixed-interval smoothing problem. SMACK utilizes a backward-filter, forward-smoother algorithm to solve the problem. The equations of motion are used to produce estimates that are compared with their corresponding measurement time histories. The procedure is iterative, providing improved state estimates until a minimum squared-error measure is achieved. In the SMACK program, the state and measurement models together represent a finite-difference approximation for the six-degree-of-freedom dynamics of a rigid body. The models are used to generate time histories which are likely to be found in a flight-test measurement set. These include onboard variables such as Euler angles, angular rates, and linear accelerations as well as tracking variables such as slant range, bearing, and elevation. Any bias or scale-factor errors associated with the state or measurement models are appended to the state vector and treated as constant but unknown parameters. The SMACK documentation covers the derivation of the solution algorithm, describes the state and measurement models, and presents several application examples that should help the analyst recognize the potential

  10. SMACK - SMOOTHING FOR AIRCRAFT KINEMATICS

    NASA Technical Reports Server (NTRS)

    Bach, R.

    1994-01-01

    The computer program SMACK (SMoothing for AirCraft Kinematics) is designed to provide flightpath reconstruction of aircraft forces and motions from measurements that are noisy or incomplete. Additionally, SMACK provides a check on instrument accuracy and data consistency. The program can be used to analyze data from flight-test experiments prior to their use in performance, stability and control, or aerodynamic modeling calculations. It can also be used in the analysis of aircraft accidents, where the actual forces and motions may have to be determined from a very limited data set. Application of a state-estimation method for flightpath reconstruction is possible because aircraft forces and motions are related by well-known equations of motion. The task of postflight state estimation is known as a nonlinear, fixed-interval smoothing problem. SMACK utilizes a backward-filter, forward-smoother algorithm to solve the problem. The equations of motion are used to produce estimates that are compared with their corresponding measurement time histories. The procedure is iterative, providing improved state estimates until a minimum squared-error measure is achieved. In the SMACK program, the state and measurement models together represent a finite-difference approximation for the six-degree-of-freedom dynamics of a rigid body. The models are used to generate time histories which are likely to be found in a flight-test measurement set. These include onboard variables such as Euler angles, angular rates, and linear accelerations as well as tracking variables such as slant range, bearing, and elevation. Any bias or scale-factor errors associated with the state or measurement models are appended to the state vector and treated as constant but unknown parameters. The SMACK documentation covers the derivation of the solution algorithm, describes the state and measurement models, and presents several application examples that should help the analyst recognize the potential

  11. Experimental model of human corpus cavernosum smooth muscle relaxation.

    PubMed

    Regadas, Rommel P; Moraes, Maria E A; Mesquita, Francisco J C; Cerqueira, Joao B G; Gonzaga-Silva, Lucio F

    2010-01-01

    To describe a technique for en bloc harvesting of the corpus cavernosum, cavernous artery and urethra from transplant organ donors and contraction-relaxation experiments with corpus cavernosum smooth muscle. The corpus cavernosum was dissected to the point of attachment with the crus penis. A 3 cm segment (corpus cavernosum and urethra) was isolated and placed in ice-cold sterile transportation buffer. Under magnification, the cavernous artery was dissected. Thus, 2 cm fragments of cavernous artery and corpus cavernosum were obtained. Strips measuring 3 x 3 x 8 mm(3) were then mounted vertically in an isolated organ bath device. Contractions were measured isometrically with a Narco-Biosystems force displacement transducer (model F-60, Narco-Biosystems, Houston, TX, USA) and recorded on a 4-channel Narco-Biosystems desk model polygraph. Phenylephrine (1 microM) was used to induce tonic contractions in the corpus cavernosum (3-5 g tension) and cavernous artery (0.5-1 g tension) until reaching a plateau. After precontraction, smooth muscle relaxants were used to produce relaxation-response curves (10(-12) M to 10(-4) M). Sodium nitroprusside was used as a relaxation control. The harvesting technique and the smooth muscle contraction-relaxation model described in this study were shown to be useful instruments in the search for new drugs for the treatment of human erectile dysfunction.

  12. Interaction of Vascular Smooth Muscle Cells Under Low Shear Stress

    NASA Technical Reports Server (NTRS)

    Seidel, Charles L.

    1998-01-01

    The blood vessel wall consists of three cellular layers, an outer adventitial, a middle medial and an inner intimal layer. When the blood vessel forms in the embryo it begins as a tube composed of a single cell type called endothelial cells. Over time, other cells are recruited from the surrounding tissue to form additional layers on the outer surface of the endothelial tube. The cells that are recruited are called mesenchymal cells. Mesenchymal cells are responsible for the production of connective tissue that holds the blood vessel together and for developing into vascular smooth muscle cells that are responsible for regulating the diameter of the vessel (1) and therefore, blood flow. In a fully developed blood vessel, the endothelial cells make- up the majority of cells in the intimal layer while the mesenchymal cells make-up the majority of cells in the medial and adventitial layers. Within the medial layer of a mature vessel, cells are organized into multiple circular layers of alternating bands of connective tissue and cells. The cell layer is composed of a mixture of mesenchymal cells that have not developed into smooth muscle cells and fully developed smooth muscle cells (2). The assembly and organization of complex tissues is directed in part by a signaling system composed of proteins on the cell surface called adhesion molecules. Adhesion molecules enable cells to recognize each other as well as the composition of the connective tissue in which they reside (3). It was hypothesized that the different cell types that compose the vascular wall possess different adhesion molecules that enable them to recognize each other and through this recognition system, form the complex layered organization of the vascular wall. In other words, the layered organization is an intrinsic property of the cells. If this hypothesis is correct then the different cells that make up the vessel wall, when mixed together, should organize themselves into a layered structure

  13. Spline-Based Smoothing of Airfoil Curvatures

    NASA Technical Reports Server (NTRS)

    Li, W.; Krist, S.

    2008-01-01

    Constrained fitting for airfoil curvature smoothing (CFACS) is a splinebased method of interpolating airfoil surface coordinates (and, concomitantly, airfoil thicknesses) between specified discrete design points so as to obtain smoothing of surface-curvature profiles in addition to basic smoothing of surfaces. CFACS was developed in recognition of the fact that the performance of a transonic airfoil is directly related to both the curvature profile and the smoothness of the airfoil surface. Older methods of interpolation of airfoil surfaces involve various compromises between smoothing of surfaces and exact fitting of surfaces to specified discrete design points. While some of the older methods take curvature profiles into account, they nevertheless sometimes yield unfavorable results, including curvature oscillations near end points and substantial deviations from desired leading-edge shapes. In CFACS as in most of the older methods, one seeks a compromise between smoothing and exact fitting. Unlike in the older methods, the airfoil surface is modified as little as possible from its original specified form and, instead, is smoothed in such a way that the curvature profile becomes a smooth fit of the curvature profile of the original airfoil specification. CFACS involves a combination of rigorous mathematical modeling and knowledge-based heuristics. Rigorous mathematical formulation provides assurance of removal of undesirable curvature oscillations with minimum modification of the airfoil geometry. Knowledge-based heuristics bridge the gap between theory and designers best practices. In CFACS, one of the measures of the deviation of an airfoil surface from smoothness is the sum of squares of the jumps in the third derivatives of a cubicspline interpolation of the airfoil data. This measure is incorporated into a formulation for minimizing an overall deviation- from-smoothness measure of the airfoil data within a specified fitting error tolerance. CFACS has been

  14. TcGPXII, a glutathione-dependent Trypanosoma cruzi peroxidase with substrate specificity restricted to fatty acid and phospholipid hydroperoxides, is localized to the endoplasmic reticulum.

    PubMed Central

    Wilkinson, Shane R; Taylor, Martin C; Touitha, Said; Mauricio, Isabel L; Meyer, David J; Kelly, John M

    2002-01-01

    Until recently, it had been thought that trypanosomes lack glutathione peroxidase activity. Here we report the subcellular localization and biochemical properties of a second glutathione-dependent peroxidase from Trypanosoma cruzi (TcGPXII). TcGPXII is a single-copy gene which encodes a 16 kDa protein that appears to be specifically dependent on glutathione as the source of reducing equivalents. Recombinant TcGPXII was purified and shown to have peroxidase activity towards a narrow substrate range, restricted to hydroperoxides of fatty acids and phospholipids. Analysis of the pathway revealed that TcGPXII activity could be readily saturated by glutathione and that the peroxidase functioned by a Ping Pong mechanism. Enzyme reduction was shown to be the rate-limiting step in this pathway. Using immunofluorescence, TcGPXII was shown to co-localize with a homologue of immunoglobulin heavy-chain binding protein (BiP), a protein restricted to the endoplasmic reticulum and Golgi. As the smooth endoplasmic reticulum is the site of phospholipid and fatty acid biosynthesis, this suggests that TcGPXII may play a specific role in the T. cruzi oxidative defence system by protecting newly synthesized lipids from peroxidation. PMID:12049643

  15. 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.

  16. Chemical method for producing smooth surfaces on silicon wafers

    DOEpatents

    Yu, Conrad

    2003-01-01

    An improved method for producing optically smooth surfaces in silicon wafers during wet chemical etching involves a pre-treatment rinse of the wafers before etching and a post-etching rinse. The pre-treatment with an organic solvent provides a well-wetted surface that ensures uniform mass transfer during etching, which results in optically smooth surfaces. The post-etching treatment with an acetic acid solution stops the etching instantly, preventing any uneven etching that leads to surface roughness. This method can be used to etch silicon surfaces to a depth of 200 .mu.m or more, while the finished surfaces have a surface roughness of only 15-50 .ANG. (RMS).

  17. The Natural Pesticide Dihydrorotenone Induces Human Plasma Cell Apoptosis by Triggering Endoplasmic Reticulum Stress and Activating p38 Signaling Pathway

    PubMed Central

    Cao, Biyin; Zhang, Zubin; Li, Jie; Schimmer, Aaron D.; He, Sudan; Mao, Xinliang

    2013-01-01

    Dihydrorotenone (DHR) is a natural pesticide widely used in farming industry, such as organic produces. DHR is a potent mitochondrial inhibitor and probably induces Parkinsonian syndrome, however, it is not known whether DHR is toxic to other systems. In the present study, we evaluated the cytotoxicity of DHR on human plasma cells. As predicted, DHR impaired mitochondrial function by decreasing mitochondrial membrane potential in plasma cells. Because mito-dysfunction leads to unfolded protein response (UPR) and endoplasmic reticulum (ER) stress, we examined the signature proteins in ER stress, including GRP78, ATF4, and CHOP. After DHR treatment, these proteins were significantly upregulated. It is reported that activation of the mitogen-activated protein kinases p38 and JNK are involved in endoplasmic reticulum stress. However, in the subsequent study, DHR was found to activate p38 but not the JNK signaling. When pre-treated with p38 inhibitor SB203580, activation of p38 and cell apoptosis induced by DHR was partially blocked. Thus, we found that DHR induced human plasma cell death by activating the p38 but not the JNK signaling pathway. Because plasma cells are very important in the immune system, this study provided a new insight in the safety evaluation of DHR application. PMID:23922854

  18. Approximation of Bivariate Functions via Smooth Extensions

    PubMed Central

    Zhang, Zhihua

    2014-01-01

    For a smooth bivariate function defined on a general domain with arbitrary shape, it is difficult to do Fourier approximation or wavelet approximation. In order to solve these problems, in this paper, we give an extension of the bivariate function on a general domain with arbitrary shape to a smooth, periodic function in the whole space or to a smooth, compactly supported function in the whole space. These smooth extensions have simple and clear representations which are determined by this bivariate function and some polynomials. After that, we expand the smooth, periodic function into a Fourier series or a periodic wavelet series or we expand the smooth, compactly supported function into a wavelet series. Since our extensions are smooth, the obtained Fourier coefficients or wavelet coefficients decay very fast. Since our extension tools are polynomials, the moment theorem shows that a lot of wavelet coefficients vanish. From this, with the help of well-known approximation theorems, using our extension methods, the Fourier approximation and the wavelet approximation of the bivariate function on the general domain with small error are obtained. PMID:24683316

  19. AFSMO/AFSCL- AIRFOIL SMOOTHING AND SCALING

    NASA Technical Reports Server (NTRS)

    Morgan, H. L

    1994-01-01

    Since its early beginnings, NASA has been actively involved in the design and testing of airfoil sections for a wide variety of applications. Recently a set of programs has been developed to smooth and scale arbitrary airfoil coordinates. The smoothing program, AFSMO, utilizes both least-squares polynomial and least-squares cubic-spline techniques to iteratively smooth the second derivatives of the y-axis airfoil coordinates with respect to a transformed x-axis system which unwraps the airfoil and stretches the nose and trailing-edge regions. The corresponding smooth airfoil coordinates are then determined by solving a tridiagonal matrix of simultaneous cubic-spline equations relating the y-axis coordinates and their corresponding second derivatives. The camber and thickness distribution of the smooth airfoil are also computed. The scaling program, AFSCL, may then be used to scale the thickness distribution generated by the smoothing program to a specified maximum thickness. Once the thickness distribution has been scaled, it is combined with the camber distribution to obtain the final scaled airfoil contour. The airfoil smoothing and scaling programs are written in FORTRAN IV for batch execution and have been implemented on a CDC CYBER 170 series computer with a central memory requirement of approximately 70K (octal) of 60 bit words. Both programs generate plotted output via CALCOMP type plotting calls. These programs were developed in 1983.

  20. Numerical Convergence In Smoothed Particle Hydrodynamics

    NASA Astrophysics Data System (ADS)

    Zhu, Qirong; Hernquist, Lars; Li, Yuexing

    2015-02-01

    We study the convergence properties of smoothed particle hydrodynamics (SPH) using numerical tests and simple analytic considerations. Our analysis shows that formal numerical convergence is possible in SPH only in the joint limit N → ∞, h → 0, and Nnb → ∞, where N is the total number of particles, h is the smoothing length, and Nnb is the number of neighbor particles within the smoothing volume used to compute smoothed estimates. Previous work has generally assumed that the conditions N → ∞ and h → 0 are sufficient to achieve convergence, while holding Nnb fixed. We demonstrate that if Nnb is held fixed as the resolution is increased, there will be a residual source of error that does not vanish as N → ∞ and h → 0. Formal numerical convergence in SPH is possible only if Nnb is increased systematically as the resolution is improved. Using analytic arguments, we derive an optimal compromise scaling for Nnb by requiring that this source of error balance that present in the smoothing procedure. For typical choices of the smoothing kernel, we find Nnb vpropN 0.5. This means that if SPH is to be used as a numerically convergent method, the required computational cost does not scale with particle number as O(N), but rather as O(N 1 + δ), where δ ≈ 0.5, with a weak dependence on the form of the smoothing kernel.

  1. AFSMO/AFSCL- AIRFOIL SMOOTHING AND SCALING

    NASA Technical Reports Server (NTRS)

    Morgan, H. L

    1994-01-01

    Since its early beginnings, NASA has been actively involved in the design and testing of airfoil sections for a wide variety of applications. Recently a set of programs has been developed to smooth and scale arbitrary airfoil coordinates. The smoothing program, AFSMO, utilizes both least-squares polynomial and least-squares cubic-spline techniques to iteratively smooth the second derivatives of the y-axis airfoil coordinates with respect to a transformed x-axis system which unwraps the airfoil and stretches the nose and trailing-edge regions. The corresponding smooth airfoil coordinates are then determined by solving a tridiagonal matrix of simultaneous cubic-spline equations relating the y-axis coordinates and their corresponding second derivatives. The camber and thickness distribution of the smooth airfoil are also computed. The scaling program, AFSCL, may then be used to scale the thickness distribution generated by the smoothing program to a specified maximum thickness. Once the thickness distribution has been scaled, it is combined with the camber distribution to obtain the final scaled airfoil contour. The airfoil smoothing and scaling programs are written in FORTRAN IV for batch execution and have been implemented on a CDC CYBER 170 series computer with a central memory requirement of approximately 70K (octal) of 60 bit words. Both programs generate plotted output via CALCOMP type plotting calls. These programs were developed in 1983.

  2. Complimentary endothelial cell/smooth muscle cell co-culture systems with alternate smooth muscle cell phenotypes.

    PubMed

    Rose, Stacey L; Babensee, Julia E

    2007-08-01

    Development of in vitro models of native and injured vasculature is crucial for better understanding altered wound healing in disease, device implantation, or tissue engineering. Conditions were optimized using polyethyleneteraphalate transwell filters for human aortic endothelial cell (HAEC)/smooth muscle cell (HASMC) co-cultures with divergent HASMC phenotypes ('more or less secretory') while maintaining quiescent HAECs. Resulting HASMC phenotype was studied at 48 and 72 h following co-culture initiation, and compared to serum and growth factor starved monocultured 'forced contractile' HASMCs. Forced contractile HASMCs demonstrated organized alpha-smooth muscle actin filaments, minimal interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1) secretion, and low intracellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and tissue factor expression. Organization of alpha-smooth muscle actin was lost in 'more secretory' HASMCs in co-culture with HAECs, and IL-8 and MCP-1 secretion, as well as ICAM-1, VCAM-1, and tissue factor expression were significantly upregulated at both time points. Alternately, 'less secretory' HASMCs in co-culture with HAECs showed similar characteristics to forced contractile HASMCs at the 48 h time point, while by the 72 h time point they behaved similarly to 'more secretory' HASMCs. These co-culture systems could be useful in better understanding vascular healing, however there remain time constraint considerations for maintaining culture integrity/cell phenotype.

  3. Excimer laser smoothing of endothelial keratoplasty grafts.

    PubMed

    Cleary, Catherine; Liu, Ying; Tang, Maolong; Li, Yan; Stoeger, Christopher; Huang, David

    2012-04-01

    To use excimer laser smoothing passes to reshape Descemet-stripping automated endothelial keratoplasty (DSAEK) endothelial grafts and to evaluate the effect on the donor endothelium. The stromal surface of microkeratome-cut DSAEK grafts was smoothed using excimer laser smoothing passes with masking fluid. Excimer laser hyperopic ablation was used to improve the uniformity of graft thickness within the optical zone. Fourier-domain optical coherence tomography was used to measure endothelial graft pachymetry, plan ablations, and evaluate donor contour. Vital dye staining was performed to assess endothelial cell damage. Scanning electron microscopy images of stromal surfaces were graded on a 5-point scale by masked observers to evaluate surface roughness. Four grafts underwent excimer laser smoothing. Vital dye staining showed no endothelial damage. Microkeratome-cut surfaces treated with laser smoothing (mean grade = 2.04) were smoother than nonsmoothed microkeratome-cut surfaces (mean grade = 4.07; P < 0.01), surfaces that underwent dry laser ablation (mean grade = 3.63; P < 0.01) and manually dissected interfaces (mean grade = 4.75; P < 0.0001). No difference was observed between stromal beds created by peeling Descemet membrane (mean grade = 1.64) compared with surfaces produced by microkeratome cutting followed by laser smoothing (mean grade = 2.04; P = 0.14). One graft underwent combined excimer smoothing and peripheral hyperopic ablation. The center-periphery thickness difference was 15 μm before ablation and 4 μm afterward. Laser smoothing passes can be used to improve the contour and smoothness of DSAEK grafts without damaging donor endothelial cells. Clinical trials are needed to determine whether reshaping donors using excimer laser can deliver improved visual outcomes after DSAEK.

  4. Some new function spaces of variable smoothness

    SciTech Connect

    Tyulenev, A I

    2015-06-30

    A new Besov space of variable smoothness is introduced on which the norm is defined in terms of difference relations. This space is shown to be the trace of a weighted Sobolev space with a weight in the corresponding Muckenhoupt class. Methods of nonlinear spline approximation are applied to derive an atomic decomposition theorem for functions in a Besov space of variable smoothness. A complete description of traces on the hyperplane of a Besov space of variable smoothness and of a weighted Besov space with a weight in the corresponding Muckenhoupt class is given. Bibliography: 27 titles.

  5. Nonequilibrium Flows with Smooth Particle Applied Mechanics.

    NASA Astrophysics Data System (ADS)

    Kum, Oyeon

    Smooth particle methods are relatively new methods for simulating solid and fluid flows though they have a 20-year history of solving complex hydrodynamic problems in astrophysics, such as colliding planets and stars, for which correct answers are unknown. The results presented in this thesis evaluate the adaptability or fitness of the method for typical hydrocode production problems. For finite hydrodynamic systems, boundary conditions are important. A reflective boundary condition with image particles is a good way to prevent a density anomaly at the boundary and to keep the fluxes continuous there. Boundary values of temperature and velocity can be separately controlled. The gradient algorithm, based on differentiating the smooth particle expressions for (urho) and (Trho), does not show numerical instabilities for the stress tensor and heat flux vector quantities which require second derivatives in space when Fourier's heat -flow law and Newton's viscous force law are used. Smooth particle methods show an interesting parallel linking them to molecular dynamics. For the inviscid Euler equation, with an isentropic ideal gas equation of state, the smooth particle algorithm generates trajectories isomorphic to those generated by molecular dynamics. The shear moduli were evaluated based on molecular dynamics calculations for the three weighting functions, B spline, Lucy, and Cusp functions. The accuracy and applicability of the methods were estimated by comparing a set of smooth particle Rayleigh -Benard problems, all in the laminar regime, to corresponding highly-accurate grid-based numerical solutions of continuum equations. Both transient and stationary smooth particle solutions reproduce the grid-based data with velocity errors on the order of 5%. The smooth particle method still provides robust solutions at high Rayleigh number where grid-based methods fails. Considerably fewer smooth particles are required than atoms in a corresponding molecular dynamics

  6. Smoothing analysis of HLSII storage ring magnets

    NASA Astrophysics Data System (ADS)

    Wang, Wei; He, Xiao-Ye; Tang, Zheng; Yao, Qiu-Yang

    2016-12-01

    Hefei Light Source (HLS) has been upgraded to improve the quality and stability of the synchrotron light, and the new facility is named HLSII. However, a final accurate adjustment is required to smooth the beam orbit after the initial instalment and alignment of the magnets. We implement a reliable smoothing method for the beam orbit of the HLSII storage ring. In addition to greatly smoothing and stabilizing the beam orbit, this method also doubles the work efficiency and significantly reduces the number of magnets adjusted and the range of the adjustments. Supported by National Natural Science Foundation of China (11275192) and the Upgrade Project of Hefei Light Source

  7. Progress in smooth particle hydrodynamics

    SciTech Connect

    Wingate, C.A.; Dilts, G.A.; Mandell, D.A.; Crotzer, L.A.; Knapp, C.E.

    1998-07-01

    Smooth Particle Hydrodynamics (SPH) is a meshless, Lagrangian numerical method for hydrodynamics calculations where calculational elements are fuzzy particles which move according to the hydrodynamic equations of motion. Each particle carries local values of density, temperature, pressure and other hydrodynamic parameters. A major advantage of SPH is that it is meshless, thus large deformation calculations can be easily done with no connectivity complications. Interface positions are known and there are no problems with advecting quantities through a mesh that typical Eulerian codes have. These underlying SPH features make fracture physics easy and natural and in fact, much of the applications work revolves around simulating fracture. Debris particles from impacts can be easily transported across large voids with SPH. While SPH has considerable promise, there are some problems inherent in the technique that have so far limited its usefulness. The most serious problem is the well known instability in tension leading to particle clumping and numerical fracture. Another problem is that the SPH interpolation is only correct when particles are uniformly spaced a half particle apart leading to incorrect strain rates, accelerations and other quantities for general particle distributions. SPH calculations are also sensitive to particle locations. The standard artificial viscosity treatment in SPH leads to spurious viscosity in shear flows. This paper will demonstrate solutions for these problems that they and others have been developing. The most promising is to replace the SPH interpolant with the moving least squares (MLS) interpolant invented by Lancaster and Salkauskas in 1981. SPH and MLS are closely related with MLS being essentially SPH with corrected particle volumes. When formulated correctly, JLS is conservative, stable in both compression and tension, does not have the SPH boundary problems and is not sensitive to particle placement. The other approach to

  8. Bidder's organ of Bufo ictericus: a light and electron microscopy analysis.

    PubMed

    Farias, C F; Carvalho-e-Silva, S P; de Brito-Gitirana, L

    2002-01-01

    Male toads of the Bufonidae Family have rudimentary ovaries designated Bidder's organs, and if the testes are removed this organ develops into a functional ovary, representing a morphological strategy for the reproduction of the species. The Bidder's organ of Bufo ictericus was examined using routine and histochemical techniques by light microscopy and transmission electron microscopy. Each Bidder's organ presented a typical ovarian morphology, being composed of a cortex and a medulla. Bidderian follicles in different stages of development were visualized in the cortex, where they are better developed. The germ cells exhibit a large oocyte with a round-shaped nucleus. The Bidderian follicles are supported by a loose net of reticular fibers. In the medullar region, collagen fibers were immersed in the matrix rich in blood vessels that also contained a small quantity of neutral glycoproteins rich in hexose and/or sialic acid and carboxylated polymers with a characteristic distribution of glycosaminoglycans. The oocyte and the follicular cells were separated by a narrow space containing microvilli. The oocyte exhibit a well developed smooth endoplasmic reticulum, a poorly developed Golgi apparatus, and occasional lysosomes. Concentric cisternal complexes are often visualized; however, their morphological significance remains unclear. The peroxisomes display a fine granular matrix without a crystalline core, with a weak 3,3'-diaminobenzidine-reaction. Intimate association between peroxisomes, peroxisomes and lipid inclusions was observed in the oocyte, suggesting its participation in yolk metabolism.

  9. Diversity and plasticity in signaling pathways that regulate smooth muscle responsiveness: Paradigms and paradoxes for the myosin phosphatase, the master regulator of smooth muscle contraction

    PubMed Central

    Eto, Masumi; Kitazawa, Toshio

    2017-01-01

    A hallmark of smooth muscle cells is their ability to adapt their functions to meet temporal and chronic fluctuations in their demands. These functions include force development and growth. Understanding the mechanisms underlying the functional plasticity of smooth muscles, the major constituent of organ walls, is fundamental to elucidating pathophysiological rationales of failures of organ functions. Also, the knowledge is expected to facilitate devising innovative strategies that more precisely monitor and normalize organ functions by targeting individual smooth muscles. Evidence has established a current paradigm that the myosin light chain phosphatase (MLCP) is a master regulator of smooth muscle responsiveness to stimuli. Cellular MLCP activity is negatively and positively regulated in response to G-protein activation and cAMP/cGMP production, respectively, through the MYPT1 regulatory subunit and an endogenous inhibitor protein named CPI-17. In this article we review the outcomes from two decade of research on the CPI-17 signaling and discuss emerging paradoxes in the view of signaling pathways regulating smooth muscle functions through MLCP. PMID:28260704

  10. Diversity and plasticity in signaling pathways that regulate smooth muscle responsiveness: Paradigms and paradoxes for the myosin phosphatase, the master regulator of smooth muscle contraction.

    PubMed

    Eto, Masumi; Kitazawa, Toshio

    2017-01-01

    A hallmark of smooth muscle cells is their ability to adapt their functions to meet temporal and chronic fluctuations in their demands. These functions include force development and growth. Understanding the mechanisms underlying the functional plasticity of smooth muscles, the major constituent of organ walls, is fundamental to elucidating pathophysiological rationales of failures of organ functions. Also, the knowledge is expected to facilitate devising innovative strategies that more precisely monitor and normalize organ functions by targeting individual smooth muscles. Evidence has established a current paradigm that the myosin light chain phosphatase (MLCP) is a master regulator of smooth muscle responsiveness to stimuli. Cellular MLCP activity is negatively and positively regulated in response to G-protein activation and cAMP/cGMP production, respectively, through the MYPT1 regulatory subunit and an endogenous inhibitor protein named CPI-17. In this article we review the outcomes from two decade of research on the CPI-17 signaling and discuss emerging paradoxes in the view of signaling pathways regulating smooth muscle functions through MLCP.

  11. Platelet-derived growth factor maintains stored calcium through a nonclustering Orai1 mechanism but evokes clustering if the endoplasmic reticulum is stressed by store depletion.

    PubMed

    McKeown, Lynn; Moss, Nicholas K; Turner, Paul; Li, Jing; Heath, Nikki; Burke, Dermot; O'Regan, David; Gilthorpe, Mark S; Porter, Karen E; Beech, David J

    2012-06-22

    Calcium entry through Orai1 channels drives vascular smooth muscle cell migration and neointimal hyperplasia. The channels are activated by the important growth factor platelet-derived growth factor (PDGF). Channel activation is suggested to depend on store depletion, which redistributes and clusters stromal interaction molecule 1 (STIM1), which then coclusters and activates Orai1. To determine the relevance of STIM1 and Orai1 redistribution in PDGF responses. Vascular smooth muscle cells were cultured from human saphenous vein. STIM1 and Orai1 were tagged with green and red fluorescent proteins to track them in live cells. Under basal conditions, the proteins were mobile but mostly independent of each other. Inhibition of sarco-endoplasmic reticulum calcium ATPase led to store depletion and dramatic redistribution of STIM1 and Orai1 into coclusters. PDGF did not evoke redistribution, even though it caused calcium release and Orai1-mediated calcium entry in the same time period. After chemical blockade of Orai1-mediated calcium entry, however, PDGF caused redistribution. Similarly, mutagenic disruption of calcium flux through Orai1 caused PDGF to evoke redistribution, showing that calcium flux through the wild-type channels had been filling the stores. Acidification of the extracellular medium to pH 6.4 caused inhibition of Orai1-mediated calcium entry and conferred capability for PDGF to evoke complete redistribution and coclustering. The data suggest that PDGF has a nonclustering mechanism by which to activate Orai1 channels and maintain calcium stores replete. Redistribution and clustering become important, however, when the endoplasmic reticulum stress signal of store depletion arises, for example when acidosis inhibits Orai1 channels.

  12. Subcellular distribution of small GTP binding proteins in pancreas: Identification of small GTP binding proteins in the rough endoplasmic reticulum

    SciTech Connect

    Nigam, S.K. )

    1990-02-01

    Subfractionation of a canine pancreatic homogenate was performed by several differential centrifugation steps, which gave rise to fractions with distinct marker profiles. Specific binding of guanosine 5{prime}-({gamma}-({sup 35}S)thio)triphosphate (GTP({gamma}-{sup 35}S)) was assayed in each fraction. Enrichment of GTP({gamma}-{sup 35}S) binding was greatest in the interfacial smooth microsomal fraction, expected to contain Golgi and other smooth vesicles. There was also marked enrichment in the rough microsomal fraction. Electron microscopy and marker protein analysis revealed the rough microsomes (RMs) to be highly purified rough endoplasmic reticulum (RER). The distribution of small (low molecular weight) GTP binding proteins was examined by a ({alpha}-{sup 32}P)GTP blot-overlay assay. Several apparent GTP binding proteins of molecular masses 22-25 kDa were detected in various subcellular fractions. In particular, at least two such proteins were found in the Golgi-enriched and RM fractions, suggesting that these small GTP binding proteins were localized to the Golgi and RER. To more precisely localize these proteins to the RER, native RMs and RMs stripped of ribosomes by puromycin/high salt were subjected to isopycnic centrifugation. The total GTP({gamma}-{sup 35}S) binding, as well as the small GTP binding proteins detected by the ({alpha}-{sup 32}P)GTP blot overlay, distributed into fractions of high sucrose density, as did the RER marker ribophorin I. Consistent with a RER localization, when the RMS were stripped of ribosomes and subjected to isopycnic centrifugation, the total GTP({gamma}-{sup 35}S) binding and the small GTP binding proteins detected in the blot-overlay assay shifted to fractions of lighter sucrose density along with the RER marker.

  13. Reduction of endoplasmic reticulum stress by 4-phenylbutyric acid prevents the development of hypoxia-induced pulmonary arterial hypertension.

    PubMed

    Koyama, Masayuki; Furuhashi, Masato; Ishimura, Shutaro; Mita, Tomohiro; Fuseya, Takahiro; Okazaki, Yusuke; Yoshida, Hideaki; Tsuchihashi, Kazufumi; Miura, Tetsuji

    2014-05-01

    Pulmonary arterial hypertension (PAH) is characterized by vasoconstriction and vascular remodeling of the pulmonary artery (PA). Recently, endoplasmic reticulum (ER) stress and inappropriate adaptation through the unfolded protein response (UPR) have been disclosed in various types of diseases. Here we examined whether ER stress is involved in the pathogenesis of PAH. Four weeks of chronic normobaric hypoxia increased right ventricular (RV) systolic pressure by 63% compared with that in normoxic controls and induced RV hypertrophy and medial thickening of the PA in C57BL/6J mice. Treatment with 4-phenylbutyric acid (4-PBA), a chemical chaperone, significantly reduced RV systolic pressure by 30%, attenuated RV hypertrophy and PA muscularization, and increased total running distance in a treadmill test by 70% in hypoxic mice. The beneficial effects of 4-PBA were associated with suppressed expression of inflammatory cytokines and ER stress markers, including Grp78 and Grp94 in the activating transcription factor-6 branch, sXbp1 and Pdi in the inositol-requiring enzyme-1 branch and Atf4 in the PKR-like ER kinase branch, and reduced phosphorylation of c-Jun NH2-terminal kinase and eukaryotic translation initiation factor-2α in the lung. The pattern of changes in ER stress and inflammatory markers by 4-PBA in the lung of the PAH model was reproduced in PA smooth muscle cells by chronic stimulation of platelet-derived growth factor-BB or hypoxia. Furthermore, knockdown of each UPR branch sensor activated other branches and promoted proliferation of PA smooth muscle cells. The findings indicate that activation of all branches of the UPR and accompanying inflammation play a major role in the pathogenesis of PAH, and that chemical chaperones are potentially therapeutic agents for PAH.

  14. Smooth muscle-like tissue constructs with circumferentially oriented cells formed by the cell fiber technology.

    PubMed

    Hsiao, Amy Y; Okitsu, Teru; Onoe, Hiroaki; Kiyosawa, Mahiro; Teramae, Hiroki; Iwanaga, Shintaroh; Kazama, Tomohiko; Matsumoto, Taro; Takeuchi, Shoji

    2015-01-01

    The proper functioning of many organs and tissues containing smooth muscles greatly depends on the intricate organization of the smooth muscle cells oriented in appropriate directions. Consequently controlling the cellular orientation in three-dimensional (3D) cellular constructs is an important issue in engineering tissues of smooth muscles. However, the ability to precisely control the cellular orientation at the microscale cannot be achieved by various commonly used 3D tissue engineering building blocks such as spheroids. This paper presents the formation of coiled spring-shaped 3D cellular constructs containing circumferentially oriented smooth muscle-like cells differentiated from dedifferentiated fat (DFAT) cells. By using the cell fiber technology, DFAT cells suspended in a mixture of extracellular proteins possessing an optimized stiffness were encapsulated in the core region of alginate shell microfibers and uniformly aligned to the longitudinal direction. Upon differentiation induction to the smooth muscle lineage, DFAT cell fibers self-assembled to coiled spring structures where the cells became circumferentially oriented. By changing the initial core-shell microfiber diameter, we demonstrated that the spring pitch and diameter could be controlled. 21 days after differentiation induction, the cell fibers contained high percentages of ASMA-positive and calponin-positive cells. Our technology to create these smooth muscle-like spring constructs enabled precise control of cellular alignment and orientation in 3D. These constructs can further serve as tissue engineering building blocks for larger organs and cellular implants used in clinical treatments.

  15. Smooth Muscle-Like Tissue Constructs with Circumferentially Oriented Cells Formed by the Cell Fiber Technology

    PubMed Central

    Hsiao, Amy Y.; Okitsu, Teru; Onoe, Hiroaki; Kiyosawa, Mahiro; Teramae, Hiroki; Iwanaga, Shintaroh; Kazama, Tomohiko; Matsumoto, Taro; Takeuchi, Shoji

    2015-01-01

    The proper functioning of many organs and tissues containing smooth muscles greatly depends on the intricate organization of the smooth muscle cells oriented in appropriate directions. Consequently controlling the cellular orientation in three-dimensional (3D) cellular constructs is an important issue in engineering tissues of smooth muscles. However, the ability to precisely control the cellular orientation at the microscale cannot be achieved by various commonly used 3D tissue engineering building blocks such as spheroids. This paper presents the formation of coiled spring-shaped 3D cellular constructs containing circumferentially oriented smooth muscle-like cells differentiated from dedifferentiated fat (DFAT) cells. By using the cell fiber technology, DFAT cells suspended in a mixture of extracellular proteins possessing an optimized stiffness were encapsulated in the core region of alginate shell microfibers and uniformly aligned to the longitudinal direction. Upon differentiation induction to the smooth muscle lineage, DFAT cell fibers self-assembled to coiled spring structures where the cells became circumferentially oriented. By changing the initial core-shell microfiber diameter, we demonstrated that the spring pitch and diameter could be controlled. 21 days after differentiation induction, the cell fibers contained high percentages of ASMA-positive and calponin-positive cells. Our technology to create these smooth muscle-like spring constructs enabled precise control of cellular alignment and orientation in 3D. These constructs can further serve as tissue engineering building blocks for larger organs and cellular implants used in clinical treatments. PMID:25734774

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

    USDA-ARS?s Scientific Manuscript database

    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. ...

  17. Biodistribution of Viscumin after Subcutaneous Injection to Mice and In Vitro Modeling of Endoplasmic Reticulum Stress.

    PubMed

    Maltseva, D V; Krainova, N A; Khaustova, N A; Nikulin, S V; Tonevitskaya, S A; Poloznikov, A A

    2017-08-01

    Viscumin (mistletoe lectin I, MLI) in concentrations of 10(-11)-10(-7) M causes endoplasmic reticulum stress and triggers unfolded protein response, a modulator of antitumor immunity, in target cells.

  18. Activating transcription factor 4 is involved in endoplasmic reticulum stress-mediated apoptosis contributing to vascular calcification.

    PubMed

    Duan, Xiao-Hui; Chang, Jin-Rui; Zhang, Jing; Zhang, Bao-Hong; Li, Yu-Lin; Teng, Xu; Zhu, Yi; Du, Jie; Tang, Chao-Shu; Qi, Yong-Fen

    2013-09-01

    Our previous work reported that endoplasmic reticulum stress (ERS)-mediated apoptosis was activated during vascular calcification (VC). Activating transcription factor 4 (ATF4) is a critical transcription factor in osteoblastogenesis and ERS-induced apoptosis. However, whether ATF4 is involved in ERS-mediated apoptosis contributing to VC remains unclear. In the present study, in vivo VC was induced in rats by administering vitamin D3 plus nicotine. Vascular smooth muscle cell (VSMC) calcification in vitro was induced by incubation in calcifying media containing β-glycerophosphate and CaCl2. ERS inhibitors taurine or 4-phenylbutyric acid attenuated ERS and VSMC apoptosis in calcified rat arteries, reduced calcification and retarded the VSMC contractile phenotype transforming into an osteoblast-like phenotype in vivo. Inhibition of ERS retarded the VSMC phenotypic transition into an osteoblast-like cell phenotype and reduced VSMC calcification and apoptosis in vitro. Interestingly, ATF4 was activated in calcified aortas and calcified VSMCs in vitro. ATF4 knockdown attenuated ERS-induced apoptosis in calcified VSMCs. ATF4 deficiency blocked VSMC calcification and negatively regulated the osteoblast phenotypic transition of VSMCs in vitro. Our results demonstrate that ATF4 was involved at least in part in the process of ERS-mediated apoptosis contributing to VC.

  19. 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

  20. 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.

  1. Endoplasmic reticulum stress in bone marrow-derived cells prevents acute cardiac inflammation and injury in response to angiotensin II.

    PubMed

    Li, T-T; Jia, L-X; Zhang, W-M; Li, X-Y; Zhang, J; Li, Y-L; Li, H-H; Qi, Y-F; Du, J

    2016-06-09

    Inflammation plays an important role in hypertensive cardiac injury. The endoplasmic reticulum (ER) stress pathway is involved in the inflammatory response. However, the role of ER stress in elevated angiotensin II (Ang II)-induced cardiac injury remains unclear. In this study, we investigated the role of ER stress in Ang II-induced hypertensive cardiac injury. Transcriptome analysis and quantitative real-time PCR showed that Ang II infusion in mice increased ER stress-related genes expression in the heart. C/EBP homologous protein (CHOP) deficiency, a key mediator of ER stress, increased infiltration of inflammatory cells, especially neutrophils, the production of inflammatory cytokines, chemokines in Ang II-infused mouse hearts. CHOP deficiency increased Ang II-induced cardiac fibrotic injury: (1) Masson trichrome staining showed increased fibrotic areas, (2) immunohistochemistry staining showed increased expression of α-smooth muscle actin, transforming growth factor β1 and (3) quantitative real-time PCR showed increased expression of collagen in CHOP-deficient mouse heart. Bone marrow transplantation experiments indicated that CHOP deficiency in bone marrow cells was responsible for Ang II-induced cardiac fibrotic injury. Moreover, TUNEL staining and flow cytometry revealed that CHOP deficiency decreased neutrophil apoptosis in response to Ang II. Taken together, our study demonstrated that hypertension induced ER stress after Ang II infusion. ER stress in bone marrow-derived cells protected acute cardiac inflammation and injury in response to Ang II.

  2. Mechanical stretch-induced endoplasmic reticulum stress, apoptosis and inflammation contribute to thoracic aortic aneurysm and dissection.

    PubMed

    Jia, Li-Xin; Zhang, Wen-Mei; Zhang, Hong-Jia; Li, Tao-Tao; Wang, Yue-Li; Qin, Yan-Wen; Gu, Hong; Du, Jie

    2015-07-01

    Thoracic aortic aneurysm/dissection (TAAD) is characterized by excessive smooth muscle cell (SMC) loss, extracellular matrix (ECM) degradation and inflammation. In response to certain stimuli, endoplasmic reticulum (ER) stress is activated and regulates apoptosis and inflammation. Excessive apoptosis promotes aortic inflammation and degeneration, leading to TAAD. Therefore, we studied the role of ER stress in TAAD formation. A lysyl oxidase inhibitor, 3-aminopropionitrile fumarate (BAPN), was administrated to induce TAAD formation in mice, which showed significant SMC loss (α-SMA level). Excessive apoptosis (TUNEL staining) and ER stress (ATF4 and CHOP), along with inflammation, were present in TAAD samples from both mouse and human. Transcriptional profiling of SMCs after mechanical stress demonstrated the expression of genes for ER stress and inflammation. To explore the causal role of ER stress in initiating degenerative signalling events and TAAD, we treated wild-type (CHOP(+/+)) or CHOP(-/-) mice with BAPN and found that CHOP deficiency protected against TAAD formation and rupture, as well as reduction in α-SMA level. Both SMC apoptosis and inflammation were significantly reduced in CHOP(-/-) mice. Moreover, SMCs isolated from CHOP(-/-) mice were resistant to mechanical stress-induced apoptosis. Taken together, our results demonstrated that mechanical stress-induced ER stress promotes SMCs apoptosis, inflammation and degeneration, providing insight into TAAD formation and progression. © 2015 Authors. Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

  3. Oxidized lipids activate autophagy in a JNK-dependent manner by stimulating the endoplasmic reticulum stress response.

    PubMed

    Haberzettl, Petra; Hill, Bradford G

    2013-01-01

    Excessive production of unsaturated aldehydes from oxidized lipoproteins and membrane lipids is a characteristic feature of cardiovascular disease. Our previous studies show that unsaturated lipid peroxidation-derived aldehydes such as 4-hydroxy-trans-2-nonenal (HNE) promote autophagy in rat aortic smooth muscle cells (RASMC). In this study, we examined the mechanism by which HNE induces autophagy. Exposure of RASMC to HNE led to the modification of several proteins, most of which were identified by mass spectrometry and confocal microscopy to be localized to the endoplasmic reticulum (ER). HNE stimulated the phosphorylation of PKR-like ER kinase and eukaryotic initiation factor 2α and increased heme oxygenase-1 (HO-1) abundance. HNE treatment also increased LC3-II formation and the phosphorylation of JNK and p38. Pharmacological inhibition of JNK, but not p38, prevented HNE-induced HO-1 expression and LC3-II formation. Inhibition of JNK increased cell death in HNE-treated cells. Pretreatment with the chemical chaperone phenylbutryic acid prevented LC3-II formation as well as JNK phosphorylation and HO-1 induction. Taken together, these data suggest that autophagic responses triggered by unsaturated aldehydes could be attributed, in part, to ER stress, which stimulates autophagy by a JNK-dependent mechanism and promotes cell survival during oxidative stress.

  4. Polypeptide and phospholipid composition of the membrane of rat liver peroxisomes: comparison with endoplasmic reticulum and mitochondrial membranes

    PubMed Central

    1982-01-01

    Membranes were isolated from highly purified peroxisomes, mitochondria, and rough and smooth microsomes of rat liver by the one-step Na2CO3 procedure described in the accompanying paper (1982, J. Cell Biol. 93:97-102). The polypeptide compositions of these membranes were determined by SDS PAGE and found to be greatly dissimilar. The peroxisomal membrane contains 12% of the peroxisomal protein and consists of three major polypeptides (21,700, 67,700 and 69,700 daltons) as well as some minor polypeptides. The major peroxisomal membrane proteins as well as most of the minor ones are absent from the endoplasmic reticulum (ER). Conversely, most ER proteins are absent from peroxisomes. By electron microscopy, purified peroxisomal membranes are approximately 6.8 nm thick and have a typical trilaminar appearance. The phospholipid/protein ratio of peroxisomal membranes is approximately 200 nmol/mg; the principal phospholipids are phosphatidyl choline and phosphatidyl ethanolamine as in ER and mitochondrial membranes. In contrast to the mitochondria, peroxisomal membranes contain no cardiolipin. All the membranes investigated contain a polypeptide band with a molecular mass of approximately 15,000 daltons. Whether this represents an exceptional common membrane protein or a coincidence is unknown. The implications of these results for the biogenesis of peroxisomes are discussed. PMID:7068748

  5. Smoothing spline primordial power spectrum reconstruction

    SciTech Connect

    Sealfon, Carolyn; Verde, Licia; Jimenez, Raul

    2005-11-15

    We reconstruct the shape of the primordial power spectrum (PPS) using a smoothing spline. Our adapted smoothing spline technique provides a complementary method to existing efforts to search for smooth features in the PPS, such as a running spectral index. With this technique we find no significant indication with Wilkinson Microwave Anisotropy Probe first-year data that the PPS deviates from a Harrison-Zeldovich spectrum and no evidence for loss of power on large scales. We also examine the effect on the cosmological parameters of the additional PPS freedom. Smooth variations in the PPS are not significantly degenerate with other cosmological parameters, but the spline reconstruction greatly increases the errors on the optical depth and baryon fraction.

  6. Smooth Ground on Rosetta Destination Comet

    NASA Image and Video Library

    2014-11-11

    A patch of relatively smooth ground on the nucleus surface of comet 67P/Churyumov-Gerasimenko appears in this image taken by the navigation camera on the European Space Agency Rosetta spacecraft in October 2014.

  7. Refractory thermal insulation for smooth metal surfaces

    NASA Technical Reports Server (NTRS)

    1964-01-01

    To protect rocket metal surfaces from engine exhaust heat, a refractory thermal insulation mixture, which adheres to smooth metals, has been developed. Insulation protection over a wide temperature range can be controlled by thickness of the applied mixture.

  8. Small Craters Engulfed by Smooth Plains

    NASA Image and Video Library

    2000-08-05

    This double ring basin top center of image was photographed during NASA Mariner 10 second encounter and shows two craters about 30 km in diameter which have been engulfed by smooth plains on the floor of the inner ring.

  9. Altered vascular smooth muscle function in the ApoE knockout mouse during the progression of atherosclerosis.

    PubMed

    Ewart, Marie-Ann; Kennedy, Simon; Macmillan, Debbi; Raja, Abhirami L N; Watt, Ian M; Currie, Susan

    2014-05-01

    Relaxation of vascular smooth muscle (VSM) requires re-uptake of cytosolic Ca(2+) into the sarcoplasmic reticulum (SR) via the Sarco/Endoplasmic Reticulum Ca(2+) ATPase (SERCA), or extrusion via the Plasma Membrane Ca(2+) ATPase (PMCA) or sodium Ca(2+) exchanger (NCX). Peroxynitrite, a reactive species formed in vascular inflammatory diseases, upregulates SERCA activity to induce relaxation but, chronically, can contribute to atherogenesis and altered vascular function by escalating endoplasmic reticulum stress. Our objectives were to determine if peroxynitrite-induced relaxation and Ca(2+) handling processes within vascular smooth muscle cells were altered as atherosclerosis develops. Aortae from control and ApoE(-/-) mice were studied histologically, functionally and for protein expression levels of SERCA and PMCA. Ca(2+) responses were assessed in dissociated aortic smooth muscle cells in the presence and absence of extracellular Ca(2+). Relaxation to peroxynitrite was concentration-dependent and endothelium-independent. The abilities of the SERCA blocker thapsigargin and the PMCA inhibitor carboxyeosin to block this relaxation were altered during fat feeding and plaque progression. SERCA levels were progressively reduced, while PMCA expression was upregulated. In ApoE(-/-) VSM cells, increases in cytosolic Ca(2+) [Ca(2+)]c in response to SERCA blockade were reduced, while SERCA-independent Ca(2+) clearance was faster compared to control. As atherosclerosis develops in the ApoE(-/-) mouse, expression and function of Ca(2+) handling proteins are altered. Up-regulation of Ca(2+) removal via PMCA may offer a potential compensatory mechanism to help normalise the dysfunctional relaxation observed during disease progression. Copyright © 2014 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  10. Smoothing Splines: Regression, Derivatives and Deconvolution.

    DTIC Science & Technology

    1981-11-01

    1977 ). Solutions of Ill - posed Problems . V. H. Winston and Sons. Wahba, G. (1975). Smoothing noisy data with spline functions. Num. Math., 24, 309...ds . (1.3) Many examples of this type may be found in Tikhonov and Arsenin ( 1977 ). The method of regularization is used to control the instability... solutions of certain minimax problems , Powell (1981) and Speckman (1981). It appears that flexibility is lost by guarding against worst cases. Smoothing

  11. Mechanotransduction, asthma, and airway smooth muscle

    PubMed Central

    Fabry, Ben; Fredberg, Jeffrey J.

    2008-01-01

    Excessive force generation by airway smooth muscle is the main culprit in excessive airway narrowing during an asthma attack. The maximum force the airway smooth muscle can generate is exquisitely sensitive to muscle length fluctuations during breathing, and is governed by complex mechanotransduction events that can best be studied by a hybrid approach in which the airway wall is modeled in silico so as to set a dynamic muscle load comparable to that experienced in vivo. PMID:18836522

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

    SciTech Connect

    Zhang, Shun; Jiang, Chunyang; Liu, Hongliang; Guan, Zhizhong; Zeng, Qiang; Zhang, Cheng; Lei, Rongrong; Xia, Tao; Gao, Hui; Yang, Lu; Chen, Yihu; Wu, Xue; Zhang, Xiaofei; Cui, Yushan; Yu, Linyu; Wang, Zhenglun; Wang, Aiguo

    2013-09-01

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

  13. The yeast p5 type ATPase, spf1, regulates manganese transport into the endoplasmic reticulum.

    PubMed

    Cohen, Yifat; Megyeri, Márton; Chen, Oscar C W; Condomitti, Giuseppe; Riezman, Isabelle; Loizides-Mangold, Ursula; Abdul-Sada, Alaa; Rimon, Nitzan; Riezman, Howard; Platt, Frances M; Futerman, Anthony H; Schuldiner, Maya

    2013-01-01

    The endoplasmic reticulum (ER) is a large, multifunctional and essential organelle. Despite intense research, the function of more than a third of ER proteins remains unknown even in the well-studied model organism Saccharomyces cerevisiae. One such protein is Spf1, which is a highly conserved, ER localized, putative P-type ATPase. Deletion of SPF1 causes a wide variety of phenotypes including severe ER stress suggesting that this protein is essential for the normal function of the ER. The closest homologue of Spf1 is the vacuolar P-type ATPase Ypk9 that influences Mn(2+) homeostasis. However in vitro reconstitution assays with Spf1 have not yielded insight into its transport specificity. Here we took an in vivo approach to detect the direct and indirect effects of deleting SPF1. We found a specific reduction in the luminal concentration of Mn(2+) in ∆spf1 cells and an increase following it's overexpression. In agreement with the observed loss of luminal Mn(2+) we could observe concurrent reduction in many Mn(2+)-related process in the ER lumen. Conversely, cytosolic Mn(2+)-dependent processes were increased. Together, these data support a role for Spf1p in Mn(2+) transport in the cell. We also demonstrate that the human sequence homologue, ATP13A1, is a functionally conserved orthologue. Since ATP13A1 is highly expressed in developing neuronal tissues and in the brain, this should help in the study of Mn(2+)-dependent neurological disorders.

  14. GOLGI TRANSPORT 1B Regulates Protein Export from the Endoplasmic Reticulum in Rice Endosperm Cells.

    PubMed

    Wang, Yihua; Liu, Feng; Ren, Yulong; Wang, Yunlong; Liu, Xi; Long, Wuhua; Wang, Di; Zhu, Jianping; Zhu, Xiaopin; Jing, Ruonan; Wu, Mingming; Hao, Yuanyuan; Jiang, Ling; Wang, Chunming; Wang, Haiyang; Bao, Yiqun; Wan, Jianmin

    2016-11-01

    Coat protein complex II (COPII) mediates the first step of anterograde transport of newly synthesized proteins from the endoplasmic reticulum (ER) to other endomembrane compartments in eukaryotes. A group of evolutionarily conserved proteins (Sar1, Sec23, Sec24, Sec13, and Sec31) constitutes the basic COPII coat machinery; however, the details of how the COPII coat assembly is regulated remain unclear. Here, we report a protein transport mutant of rice (Oryza sativa), named glutelin precursor accumulation4 (gpa4), which accumulates 57-kD glutelin precursors and forms two types of ER-derived abnormal structures. GPA4 encodes the evolutionarily conserved membrane protein GOT1B (also known as GLUP2), homologous to the Saccharomyces cerevisiae GOT1p. The rice GOT1B protein colocalizes with Arabidopsis thaliana Sar1b at Golgi-associated ER exit sites (ERESs) when they are coexpressed in Nicotiana benthamiana Moreover, GOT1B physically interacts with rice Sec23, and both proteins are present in the same complex(es) with rice Sar1b. The distribution of rice Sar1 in the endomembrane system, its association with rice Sec23c, and the ERES organization pattern are significantly altered in the gpa4 mutant. Taken together, our results suggest that GOT1B plays an important role in mediating COPII vesicle formation at ERESs, thus facilitating anterograde transport of secretory proteins in plant cells. © 2016 American Society of Plant Biologists. All rights reserved.

  15. Endothelin receptor-specific control of endoplasmic reticulum stress and apoptosis in the kidney

    PubMed Central

    De Miguel, Carmen; Hamrick, William C.; Hobbs, Janet L.; Pollock, David M.; Carmines, Pamela K.; Pollock, Jennifer S.

    2017-01-01

    Endothelin-1 (ET-1) promotes renal damage during cardiovascular disease; yet, the molecular mechanisms involved remain unknown. Endoplasmic reticulum (ER) stress, triggered by unfolded protein accumulation in the ER, contributes to apoptosis and organ injury. These studies aimed to determine whether the ET-1 system promotes renal ER stress development in response to tunicamycin. ETB deficient (ETB def) or transgenic control (TG-con) rats were used in the presence or absence of ETA receptor antagonism. Tunicamycin treatment similarly increased cortical ER stress markers in both rat genotypes; however, only ETB def rats showed a 14–24 fold increase from baseline for medullary GRP78, sXBP-1, and CHOP. Pre-treatment of TG-con rats with the ETA blocker ABT-627 for 1 week prior to tunicamycin injection significantly reduced the ER stress response in cortex and medulla, and also inhibited renal apoptosis. Pre-treatment with ABT-627 failed to decrease renal ER stress and apoptosis in ETB def rats. In conclusion, the ET-1 system is important for the development of tunicamycin-induced renal ER stress and apoptosis. ETA receptor activation induces renal ER stress genes and apoptosis, while functional activation of the ETB receptor has protective effects. These results highlight targeting the ETA receptor as a therapeutic approach against ER stress-induced kidney injury. PMID:28230089

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

    PubMed Central

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

    2017-01-01

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

  17. A novel protein involved in heart development in Ambystoma mexicanum is localized in endoplasmic reticulum.

    PubMed

    Jia, P; Zhang, C; Huang, X P; Poda, M; Akbas, F; Lemanski, S L; Erginel-Unaltuna, N; Lemanski, L F

    2008-11-01

    The discovery of the naturally occurring cardiac non-function (c) animal strain in Ambystoma mexicanum (axolotl) provides a valuable animal model to study cardiomyocyte differentiation. In homozygous mutant animals (c/c), rhythmic contractions of the embryonic heart are absent due to a lack of organized myofibrils. We have previously cloned a partial sequence of a peptide cDNA (N1) from an anterior-endoderm-conditioned-medium RNA library that had been shown to be able to rescue the mutant phenotype. In the current studies we have fully cloned the N1 full length cDNA sequence from the library. N1 protein has been detected in both adult heart and skeletal muscle but not in any other adult tissues. GFP-tagged expression of the N1 protein has revealed localization of the N1 protein in the endoplasmic reticulum (ER). Results from in situ hybridization experiments have confirmed the dramatic decrease of expression of N1 mRNA in mutant (c/c) embryos indicating that the N1 gene is involved in heart development.

  18. Mapping the Interactome of a Major Mammalian Endoplasmic Reticulum Heat Shock Protein 90

    PubMed Central

    Hong, Feng; Mohammad Rachidi, Saleh; Lundgren, Debbie; Han, David; Huang, Xiu; Zhao, Hongyu; Kimura, Yayoi; Hirano, Hisashi; Ohara, Osamu; Udono, Heichiiro; Meng, Songdong; Liu, Bei; Li, Zihai

    2017-01-01

    Up to 10% of cytosolic proteins are dependent on the mammalian heat shock protein 90 (HSP90) for folding. However, the interactors of its endoplasmic reticulum (ER) paralogue (gp96, Grp94 and HSP90b1) has not been systematically identified. By combining genetic and biochemical approaches, we have comprehensively mapped the interactome of gp96 in macrophages and B cells. A total of 511 proteins were reduced in gp96 knockdown cells, compared to levels observed in wild type cells. By immunoprecipitation, we found that 201 proteins associated with gp96. Gene Ontology analysis indicated that these proteins are involved in metabolism, transport, translation, protein folding, development, localization, response to stress and cellular component biogenesis. While known gp96 clients such as integrins, Toll-like receptors (TLRs) and Wnt co-receptor LRP6, were confirmed, cell surface HSP receptor CD91, TLR4 pathway protein CD180, WDR1, GANAB and CAPZB were identified as potentially novel substrates of gp96. Taken together, our study establishes gp96 as a critical chaperone to integrate innate immunity, Wnt signaling and organ development. PMID:28056051

  19. Lack of cortical endoplasmic reticulum protein Ist2 alters sodium accumulation in Saccharomyces cerevisiae cells.

    PubMed

    Papouskova, Klara; Andrsova, Marketa; Sychrova, Hana

    2017-03-01

    The maintenance of intracellular alkali-metal-cation homeostasis is a fundamental property of all living organisms, including the yeast Saccharomyces cerevisiae. Several transport systems are indispensable to ensure proper alkali-metal-cation levels in the yeast cytoplasm and organelles. Ist2 is an endoplasmic reticulum (ER)-resident protein involved, together with other tethering proteins, in the formation of contacts between the plasma and ER membranes. As IST2 gene deletion was shown to influence yeast growth in the presence of sodium, we focused on the roles of Ist2 in the cell response to the presence of various concentrations of alkali metal cations, and its interactions with characterised plasma membrane alkali-metal-cation transporters. Most importantly, we show that, in BY4741 background, the lack of Ist2 results in the accumulation of higher amounts of sodium when the cells are exposed to the presence of this cation, demonstrating the importance of Ist2 for the maintenance of low intracellular levels of toxic sodium. As the function and localisation of alkali-metal-cation exporters is not affected in ist2Δ cells, IST2 deletion results in an increased non-specific uptake of sodium to cells. Moreover, the deletion of IST2 influences relative cell membrane potential, pHin and the growth of cells in the presence of a limiting K+ concentration. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. ATAD3 proteins: brokers of a mitochondria-endoplasmic reticulum connection in mammalian cells.

    PubMed

    Baudier, Jacques

    2017-09-20

    In yeast, a sequence of physical and genetic interactions termed the endoplasmic reticulum (ER)-mitochondria organizing network (ERMIONE) controls mitochondria-ER interactions and mitochondrial biogenesis. Several functions that characterize ERMIONE complexes are conserved in mammalian cells, suggesting that a similar tethering complex must exist in metazoans. Recent studies have identified a new family of nuclear-encoded ATPases associated with diverse cellular activities (AAA+-ATPase) mitochondrial membrane proteins specific to multicellular eukaryotes, called the ATPase family AAA domain-containing protein 3 (ATAD3) proteins (ATAD3A and ATAD3B). These proteins are crucial for normal mitochondrial-ER interactions and lie at the heart of processes underlying mitochondrial biogenesis. ATAD3A orthologues have been studied in flies, worms, and mammals, highlighting the widespread importance of this gene during embryonic development and in adulthood. ATAD3A is a downstream effector of target of rapamycin (TOR) signalling in Drosophila and exhibits typical features of proteins from the ERMIONE-like complex in metazoans. In humans, mutations in the ATAD3A gene represent a new link between altered mitochondrial-ER interaction and recognizable neurological syndromes. The primate-specific ATAD3B protein is a biomarker of pluripotent embryonic stem cells. Through negative regulation of ATAD3A function, ATAD3B supports mitochondrial stemness properties. © 2017 Cambridge Philosophical Society.

  1. Cadmium impairs protein folding in the endoplasmic reticulum and induces the unfolded protein response.

    PubMed

    Le, Quynh Giang; Ishiwata-Kimata, Yuki; Kohno, Kenji; Kimata, Yukio

    2016-08-01

    Cellular exposure to cadmium is known to strongly induce the unfolded protein response (UPR), which suggests that the endoplasmic reticulum (ER) is preferentially damaged by cadmium. According to recent reports, the UPR is induced both dependent on and independently of accumulation of unfolded proteins in the ER. In order to understand the toxic mechanism of cadmium, here we investigated how cadmium exposure leads to Ire1 activation, which triggers the UPR, using yeast Saccharomyces cerevisiae as a model organism. Cadmium poorly induced the UPR when Ire1 carried a mutation that impairs its ability to recognize unfolded proteins. Ire1 activation by cadmium was also attenuated by the chemical chaperone 4-phenylbutyrate. Cadmium caused sedimentation of BiP, the molecular chaperone in the ER, which suggests the ER accumulation of unfolded proteins. A green fluorescent protein-based reporter assay also indicated that cadmium damages the oxidative protein folding in the ER. We also found that an excess concentration of extracellular calcium attenuates the Ire1 activation by cadmium. Taken together, we propose that cadmium exposure leads to the UPR induction through impairment of protein folding in the ER. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Quantitative proteomics reveal proteins enriched in tubular endoplasmic reticulum of Saccharomyces cerevisiae

    PubMed Central

    Wang, Xinbo; Li, Shanshan; Wang, Haicheng; Shui, Wenqing; Hu, Junjie

    2017-01-01

    The tubular network is a critical part of the endoplasmic reticulum (ER). The network is shaped by the reticulons and REEPs/Yop1p that generate tubules by inducing high membrane curvature, and the dynamin-like GTPases atlastin and Sey1p/RHD3 that connect tubules via membrane fusion. However, the specific functions of this ER domain are not clear. Here, we isolated tubule-based microsomes from Saccharomyces cerevisiae via classical cell fractionation and detergent-free immunoprecipitation of Flag-tagged Yop1p, which specifically localizes to ER tubules. In quantitative comparisons of tubule-derived and total microsomes, we identified a total of 79 proteins that were enriched in the ER tubules, including known proteins that organize the tubular ER network. Functional categorization of the list of proteins revealed that the tubular ER network may be involved in membrane trafficking, lipid metabolism, organelle contact, and stress sensing. We propose that affinity isolation coupled with quantitative proteomics is a useful tool for investigating ER functions. DOI: http://dx.doi.org/10.7554/eLife.23816.001 PMID:28287394

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

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

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

  4. The endoplasmic reticulum-associated degradation is necessary for plant salt tolerance

    PubMed Central

    Liu, Lijing; Cui, Feng; Li, Qingliang; Yin, Bojiao; Zhang, Huawei; Lin, Baoying; Wu, Yaorong; Xia, Ran; Tang, Sanyuan; Xie, Qi

    2011-01-01

    Eukaryotic organisms have quality-control mechanisms that allow misfolded or unassembled proteins to be retained in the endoplasmic reticulum (ER) and subsequently degraded by ER-associated degradation (ERAD). The ERAD pathway is well studied in yeast and mammals; however, the biological functions of plant ERAD have not been reported. Through molecular and cellular biological approaches, we found that ERAD is necessary for plants to overcome salt stress. Upon salt treatment ubiquitinated proteins increased in plant cells, especially unfolded proteins that quickly accumulated in the ER and subsequently induced ER stress responses. Defect in HRD3A of the HRD1/HRD3 complex of the ERAD pathway resulted in alteration of the unfolded protein response (UPR), increased plant sensitivity to salt, and retention of ERAD substrates in plant cells. Furthermore, we demonstrated that Ca2+ release from the ER is involved in the elevation of UPR and reactive oxygen species (ROS) participates the ERAD-related plant salt response pathway. PMID:21187857

  5. Patenting the gene-hubs of endoplasmic reticulum stress: the systems biology approach.

    PubMed

    Rangel-Aldao, Rafael

    2007-01-01

    An unprecedented and accelerated process of privatizing biological information is emerging from the new techniques of systems biology as they are used to develop novel treatments to key multigenic ailments that account for a large share of mortality world-wide, including cardiovascular disease, cancer, obesity, and diabetes. The systems approach potentially allows the capture of proprietary knowledge at the cross-roads of the flow of biological information preceding these diseases, namely, from the endoplasmic reticulum stress response downstream to inflammation and disease. Although it still holds true that such pathways cannot be patented, methods and chemical substances discussed here are the subject of patents and applications by major research universities and biopharmaceutical companies to a considerable degree of overlapping information. Because biological information pathways are organized into hierarchical networks, the race seems to be on the regulation of the upstream functional modules, and because these complex networks are dominated by gene-hubs and their translation products, the winner will be the one that can appropriate specific and well described methods and substances to control the upper levels of regulation of the entire system. The road to success, however, lays formidable obstacles ahead due to the long and difficult processes separating applications being filed, from patents already issued and these from those that have survived validity litigation. It will be expected that for the sake of mankind, patents pools will be offered to develop novel therapeutics based on the biological information controlled by gene-hubs.

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

    PubMed

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

    2014-10-03

    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. IGL-1 solution reduces endoplasmic reticulum stress and apoptosis in rat liver transplantation

    PubMed Central

    Mosbah, I B; Zaouali, M A; Martel, C; Bjaoui, M; Abdennebi, H B; Hotter, G; Brenner, C; Roselló-Catafau, J

    2012-01-01

    Injury due to cold ischemia reperfusion (I/R) is a major cause of primary graft non-function following liver transplantation. We postulated that I/R-induced cellular damage during liver transplantation might affect the secretory pathway, particularly at the endoplasmic reticulum (ER). We examined the involvement of ER stress in organ preservation, and compared cold storage in University of Wisconsin (UW) solution and in Institute Georges Lopez-1 (IGL-1) solution. In one group of rats, livers were preserved in UW solution for 8 h at 4 °C, and then orthotopic liver transplantation was performed according to Kamada's cuff technique. In another group, livers were preserved in IGL-1 solution. The effect of each preservation solution on the induction of ER stress, hepatic injury, mitochondrial damage and cell death was evaluated. As expected, we found increased ER stress after liver transplantation. IGL-1 solution significantly attenuated ER damage by reducing the activation of three pathways of unfolded protein response and their effector molecules caspase-12, C/EBP homologous protein-10, X-box-binding protein 1, tumor necrosis factor-associated factor 2 and eukaryotic translation initiation factor 2. This attenuation of ER stress was associated with a reduction in hepatic injury and cell death. Our results show that IGL-1 solution may be a useful means to circumvent excessive ER stress reactions associated with liver transplantation, and may optimize graft quality. PMID:22402603

  8. Characterization of an Endoplasmic Reticulum-associated Silaffin Kinase from the Diatom Thalassiosira pseudonana*

    PubMed Central

    Sheppard, Vonda; Poulsen, Nicole; Kröger, Nils

    2010-01-01

    The formation of SiO2-based cell walls by diatoms (a large group of unicellular microalgae) is a well established model system for the study of molecular mechanisms of biological mineral morphogenesis (biomineralization). Diatom biomineralization involves highly phosphorylated proteins (silaffins and silacidins), analogous to other biomineralization systems, which also depend on diverse sets of phosphoproteins (e.g. mammalian teeth and bone, mollusk shells, and sponge silica). The phosphate moieties on biomineralization proteins play an essential role in mineral formation, yet the kinases catalyzing the phosphorylation of these proteins have remained poorly characterized. Recent functional genomics studies on the diatom Thalassiosira pseudonana have revealed >100 proteins potentially involved in diatom silica formation. Here we have characterized the biochemical properties and biological function of one of these proteins, tpSTK1. Multiple tpSTK1-like proteins are encoded in diatom genomes, all of which exhibit low but significant sequence similarity to kinases from other organisms. We show that tpSTK1 has serine/threonine kinase activity capable of phosphorylating silaffins but not silacidins. Cell biological and biochemical analysis demonstrated that tpSTK1 is an abundant component of the lumen of the endoplasmic reticulum. The present study provides the first molecular structure of a kinase that appears to catalyze phosphorylation of biomineral forming proteins in vivo. PMID:19889629

  9. Nox4-Derived H2O2 Mediates Endoplasmic Reticulum Signaling through Local Ras Activation▿

    PubMed Central

    Wu, Ru-Feng; Ma, Zhenyi; Liu, Zhe; Terada, Lance S.

    2010-01-01

    The unfolded-protein response (UPR) of the endoplasmic reticulum (ER) has been linked to oxidant production, although the molecular details and functional significance of this linkage are poorly understood. Using a ratiometric H2O2 sensor targeted to different subcellular compartments, we demonstrate specific production of H2O2 by the ER in response to the stressors tunicamycin and HIV-1 Tat, but not to thapsigargin or dithiothreitol. Knockdown of the oxidase Nox4, expressed on ER endomembranes, or expression of ER-targeted catalase blocked ER H2O2 production by tunicamycin and Tat and prevented the UPR following exposure to these two agonists, but not to thapsigargin or dithiothreitol. Tat also triggered Nox4-dependent, sustained activation of Ras leading to ERK, but not phosphatidylinositol 3-kinase (PI3K)/mTOR, pathway activation. Cell fractionation studies and green fluorescent protein (GFP) fusions of GTPase effector binding domains confirmed selective activation of endogenous RhoA and Ras on the ER surface, with ER-associated K-Ras acting upstream of the UPR and downstream of Nox4. Notably, the Nox4/Ras/ERK pathway induced autophagy, and suppression of autophagy unmasked cell death and prevented differentiation of endothelial cells in 3-dimensional matrix. We conclude that the ER surface provides a platform to spatially organize agonist-specific Nox4-dependent oxidative signaling events, leading to homeostatic protective mechanisms rather than oxidative stress. PMID:20457808

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

    DTIC Science & Technology

    2015-07-01

    1 AWARD NUMBER: W81XWH-14-1-0203 TITLE: The Endoplasmic Reticulum Stress Protein Calreticulin in Diabetic Chronic Kidney Disease PRINCIPAL...COVERED 07/01/2014-06/30/2015 4. TITLE AND SUBTITLE The Endoplasmic Reticulum Stress Protein Calreticulin in Diabetic Chronic Kidney Disease 5a...NUMBER(S) 13. SUPPLEMENTARY NOTES 14. ABSTRACT We hypothesize that ER stress induced by glucose in diabetes promotes diabetic CKD through CRT stimulation

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

    DTIC Science & Technology

    2016-07-01

    AWARD NUMBER: W81XWH-14-1-0203 TITLE: The Endoplasmic Reticulum Stress Protein Calreticulin in Diabetic Chronic Kidney Disease PRINCIPAL...1 July 2015- 30 June 2016 4. TITLE AND SUBTITLE The Endoplasmic Reticulum Stress Protein Calreticulin in Diabetic Chronic Kidney Disease 5a...We hypothesize that ER stress induced by glucose in diabetes promotes diabetic CKD through CRT stimulation of TGF-beta-dependent calcium/NFAT

  12. Beam-smoothing investigation on Heaven I

    NASA Astrophysics Data System (ADS)

    Xiang, Yi-huai; Gao, Zhi-xing; Tong, Xiao-hui; Dai, Hui; Tang, Xiu-zhang; Shan, Yu-sheng

    2007-01-01

    Directly driven targets for inertial confinement fusion (ICF) require laser beams with extremely smooth irradiance profiles to prevent hydrodynamic instabilities that destroy the spherical symmetry of the target during implosion. Such instabilities can break up and mix together the target's wall and fuel material, preventing it from reaching the density and temperature required for fusion ignition. 1,2 Measurements in the equation of state (EOS) experiments require laser beams with flat-roofed profiles to generate uniform shockwave 3. Some method for beam smooth, is thus needed. A technique called echelon-free induced spatial incoherence (EFISI) is proposed for producing smooth target beam profiles with large KrF lasers. The idea is basically an image projection technique that projects the desired time-averaged spatial profile onto the target via the laser system, using partially coherent broadband lighe. Utilize the technique, we developing beam- smoothing investigation on "Heaven I". At China Institute of Atomic Energy , a new angular multiplexing providing with beam-smoothing function has been developed, the total energy is 158J, the stability of energy is 4%, the pulse duration is 25ns, the effective diameter of focusing spot is 400um, and the ununiformity is about 1.6%, the power density on the target is about 3.7×10 12W/cm2. At present, the system have provided steady and smooth laser irradiation for EOS experiments.

  13. Vascular smooth muscle phenotypic diversity and function

    PubMed Central

    2010-01-01

    The control of force production in vascular smooth muscle is critical to the normal regulation of blood flow and pressure, and altered regulation is common to diseases such as hypertension, heart failure, and ischemia. A great deal has been learned about imbalances in vasoconstrictor and vasodilator signals, e.g., angiotensin, endothelin, norepinephrine, and nitric oxide, that regulate vascular tone in normal and disease contexts. In contrast there has been limited study of how the phenotypic state of the vascular smooth muscle cell may influence the contractile response to these signaling pathways dependent upon the developmental, tissue-specific (vascular bed) or disease context. Smooth, skeletal, and cardiac muscle lineages are traditionally classified into fast or slow sublineages based on rates of contraction and relaxation, recognizing that this simple dichotomy vastly underrepresents muscle phenotypic diversity. A great deal has been learned about developmental specification of the striated muscle sublineages and their phenotypic interconversions in the mature animal under the control of mechanical load, neural input, and hormones. In contrast there has been relatively limited study of smooth muscle contractile phenotypic diversity. This is surprising given the number of diseases in which smooth muscle contractile dysfunction plays a key role. This review focuses on smooth muscle contractile phenotypic diversity in the vascular system, how it is generated, and how it may determine vascular function in developmental and disease contexts. PMID:20736412

  14. A 3D Contact Smoothing Method

    SciTech Connect

    Puso, M A; Laursen, T A

    2002-05-02

    Smoothing of contact surfaces can be used to eliminate the chatter typically seen with node on facet contact and give a better representation of the actual contact surface. The latter affect is well demonstrated for problems with interference fits. In this work we present two methods for the smoothing of contact surfaces for 3D finite element contact. In the first method, we employ Gregory patches to smooth the faceted surface in a node on facet implementation. In the second method, we employ a Bezier interpolation of the faceted surface in a mortar method implementation of contact. As is well known, node on facet approaches can exhibit locking due to the failure of the Babuska-Brezzi condition and in some instances fail the patch test. The mortar method implementation is stable and provides optimal convergence in the energy of error. In the this work we demonstrate the superiority of the smoothed versus the non-smoothed node on facet implementations. We also show where the node on facet method fails and some results from the smoothed mortar method implementation.

  15. Reduction of endoplasmic reticulum Ca2+ levels favors plasma membrane surface exposure of calreticulin.

    PubMed

    Tufi, R; Panaretakis, T; Bianchi, K; Criollo, A; Fazi, B; Di Sano, F; Tesniere, A; Kepp, O; Paterlini-Brechot, P; Zitvogel, L; Piacentini, M; Szabadkai, G; Kroemer, G

    2008-02-01

    Some chemotherapeutic agents can elicit apoptotic cancer cell death, thereby activating an anticancer immune response that influences therapeutic outcome. We previously reported that anthracyclins are particularly efficient in inducing immunogenic cell death, correlating with the pre-apoptotic exposure of calreticulin (CRT) on the plasma membrane surface of anthracyclin-treated tumor cells. Here, we investigated the role of cellular Ca(2+) homeostasis on CRT exposure. A neuroblastoma cell line (SH-SY5Y) failed to expose CRT in response to anthracyclin treatment. This defect in CRT exposure could be overcome by the overexpression of Reticulon-1C, a manipulation that led to a decrease in the Ca(2+) concentration within the endoplasmic reticulum lumen. The combination of Reticulon-1C expression and anthracyclin treatment yielded more pronounced endoplasmic reticulum Ca(2+) depletion than either of the two manipulations alone. Chelation of intracellular (and endoplasmic reticulum) Ca(2+), targeted expression of the ligand-binding domain of the IP(3) receptor and inhibition of the sarco-endoplasmic reticulum Ca(2+)-ATPase pump reduced endoplasmic reticulum Ca(2+) load and promoted pre-apoptotic CRT exposure on the cell surface, in SH-SY5Y and HeLa cells. These results provide evidence that endoplasmic reticulum Ca(2+) levels control the exposure of CRT.

  16. Endoplasmic Reticulum Stress and Oxidative Stress: A Vicious Nexus Implicated in Bowel Disease Pathophysiology

    PubMed Central

    Chong, Wai Chin; Shastri, Madhur D.; Eri, Rajaraman

    2017-01-01

    The endoplasmic reticulum (ER) is a complex protein folding and trafficking organelle. Alteration and discrepancy in the endoplasmic reticulum environment can affect the protein folding process and hence, can result in the production of misfolded proteins. The accumulation of misfolded proteins causes cellular damage and elicits endoplasmic reticulum stress. Under such stress conditions, cells exhibit reduced functional synthesis, and will undergo apoptosis if the stress is prolonged. To resolve the ER stress, cells trigger an intrinsic mechanism called an unfolded protein response (UPR). UPR is an adaptive signaling process that triggers multiple pathways through the endoplasmic reticulum transmembrane transducers, to reduce and remove misfolded proteins and improve the protein folding mechanism, in order to improve and maintain endoplasmic reticulum homeostasis. An increasing number of studies support the view that oxidative stress has a strong connection with ER stress. During the protein folding process, reactive oxygen species are produced as by-products, leading to impaired reduction-oxidation (redox) balance conferring oxidative stress. As the protein folding process is dependent on redox homeostasis, the oxidative stress can disrupt the protein folding mechanism and enhance the production of misfolded proteins, causing further ER stress. It is proposed that endoplasmic reticulum stress and oxidative stress together play significant roles in the pathophysiology of bowel diseases. PMID:28379196

  17. Endoplasmic Reticulum Stress Plays a Key Role in the Pathogenesis of Diabetic Peripheral Neuropathy

    PubMed Central

    Lupachyk, Sergey; Watcho, Pierre; Stavniichuk, Roman; Shevalye, Hanna; Obrosova, Irina G.

    2013-01-01

    Endoplasmic reticulum stress resulting from abnormal folding of newly synthesized proteins impairs metabolism, transcriptional regulation, and gene expression, and it is a key mechanism of cell injury. Endoplasmic reticulum stress plays an important role in cardiovascular and neurodegenerative diseases, cancer, and diabetes. We evaluated the role for this phenomenon in diabetic peripheral neuropathy. Endoplasmic reticulum stress manifest in upregulation of multiple components of unfolded protein response was identified in neural tissues (sciatic nerve, spinal cord) of streptozotocin diabetic rats and mice. A chemical chaperone, trimethylamine oxide, administered for 12 weeks after induction of diabetes (110 mg⋅kg−1⋅d−1, a prevention paradigm) attenuated endoplasmic reticulum stress, peripheral nerve dysfunction, intraepidermal nerve fiber loss, and sciatic nerve and spinal cord oxidative-nitrative stress in streptozotocin diabetic rats. Similar effects on diabetes-induced endoplasmic reticulum stress and peripheral nerve dysfunction were observed with a structurally unrelated chemical chaperone, 4-phenylbutyric acid (100 mg⋅kg−1⋅d−1, intraperitoneal). CCAAT/enhancer-binding protein homologous protein (CHOP)−/− mice made diabetic with streptozotocin displayed less severe sciatic nerve oxidative-nitrative stress and peripheral neuropathy than the wild-type (C57Bl6/J) mice. Neither chemical chaperones nor CHOP gene deficiency reduced diabetic hyperglycemia. Our findings reveal an important role of endoplasmic reticulum stress in the development of diabetic peripheral neuropathy and identify a potential new therapeutic target. PMID:23364451

  18. Retrograde transport of toxins across the endoplasmic reticulum membrane.

    PubMed

    Lord, J M; Deeks, E; Marsden, C J; Moore, K; Pateman, C; Smith, D C; Spooner, R A; Watson, P; Roberts, L M

    2003-12-01

    Several protein toxins, including the A chain of the plant protein ricin (RTA), enter mammalian cells by endocytosis and catalytically modify cellular components to disrupt essential cellular processes. In the case of ricin, the process inhibited is protein synthesis. In order to reach their cytosolic substrates, several toxins undergo retrograde transport to the ER (endoplasmic reticulum) before translocating across the ER membrane. To achieve this export, these toxins exploit the ERAD (ER-associated protein degradation) pathway but must escape, at least in part, the normal degradative fate of ERAD substrates in order to intoxicate the cell. Toxins that translocate from the ER have an unusually low lysine content that reduces the likelihood of ubiquitination and ubiquitin-mediated proteasomal degradation. We have changed the two lysyl residues normally present in RTA to arginyl residues. Their replacement in RTA did not have a significant stabilizing effect on the protein, suggesting that the endogenous lysyl residues are not sites for ubiquitin attachment. However, when four additional lysyl residues were introduced into RTA in a way that did not compromise the activity, structure or stability of the toxin, degradation was significantly enhanced. Enhanced degradation resulted from ubiquitination that predisposed the toxin to proteasomal degradation. Treatment with the proteasomal inhibitor lactacystin increased the cytotoxicity of the lysine-enriched RTA to a level approaching that of wild-type RTA.

  19. Apoptosis, autophagy & endoplasmic reticulum stress in diabetes mellitus

    PubMed Central

    Demirtas, Levent; Guclu, Aydin; Erdur, Fatih Mehmet; Akbas, Emin Murat; Ozcicek, Adalet; Onk, Didem; Turkmen, Kultigin

    2016-01-01

    The prevalence of diabetes mellitus (DM) is increasing secondary to increased consumption of food and decreased physical activity worldwide. Hyperglycaemia, insulin resistance and hypertrophy of pancreatic beta cells occur in the early phase of diabetes. However, with the progression of diabetes, dysfunction and loss of beta cells occur in both types 1 and 2 DM. Programmed cell death also named apoptosis is found to be associated with diabetes, and apoptosis of beta cells might be the main mechanism of relative insulin deficiency in DM. Autophagic cell death and apoptosis are not entirely distinct programmed cell death mechanisms and share many of the regulator proteins. These processes can occur in both physiologic and pathologic conditions including DM. Besides these two important pathways, endoplasmic reticulum (ER) also acts as a cell sensor to monitor and maintain cellular homeostasis. ER stress has been found to be associated with autophagy and apoptosis. This review was aimed to describe the interactions between apoptosis, autophagy and ER stress pathways in DM. PMID:28256459

  20. 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.

  1. Unique defense strategy by the endoplasmic reticulum body in plants.

    PubMed

    Yamada, Kenji; Hara-Nishimura, Ikuko; Nishimura, Mikio

    2011-12-01

    The endoplasmic reticulum (ER) is a site for the production of secretory proteins. Plants have developed ER subdomains for protein storage. The ER body is one such structure, which is observed in Brassicaceae plants. ER bodies accumulate in seedlings and roots or in wounded leaves in Arabidopsis. ER bodies contain high amounts of the β-glucosidases PYK10/BGLU23 in seedlings and roots or BGLU18 in wounded tissues. These results suggest that ER bodies are involved in the metabolism of glycoside molecules, presumably to produce repellents against pests and fungi. When Arabidopsis roots are homogenized, PYK10 formed large protein aggregates that include other β-glucosidases (BGLU21 and BGLU22), GDSL lipase-like proteins (GLL22) and cytosolic jacalin-related lectins (PBP1/JAL30, JAL31, JAL33, JAL34 and JAL35). Glucosidase activity increases by the aggregate formation. NAI1, a basic helix-loop-helix transcription factor, regulates the expression of the ER body proteins PYK10 and NAI2. Reduced expression of NAI2, PYK10 and BGLU21 resulted in abnormal ER body formation, indicating that these components regulate ER body formation. PYK10, BGLU21 and BGLU22 possess hydrolytic activity for scopolin, a coumaroyl glucoside that accumulates in the roots of Arabidopsis, and nai1 and pyk10 mutants are more susceptible to the symbiotic fungus Piriformospora indica. Therefore, it appears that the ER body is a unique organelle of Brassicaceae plants that is important for defense against pests and fungi.

  2. Association of Legionella pneumophila with the macrophage endoplasmic reticulum.

    PubMed Central

    Swanson, M S; Isberg, R R

    1995-01-01

    Legionella pneumophila replicates within a membrane-bounded compartment that is studded with ribosomes. In this study we investigated whether these ribosomes originate from the cytoplasmic pool or are associated with host endoplasmic reticulum (ER). Immunofluorescence and electron microscopic localization studies of ER proteins in macrophages infected with L. pneumophila indicated that the bacteria reside in a compartment surrounded by ER. An L. pneumophila mutant that grows slowly in macrophages was slow to associate with host ER, providing genetic evidence in support of the hypothesis that this specialized vacuole is required for intracellular bacterial growth. Ultrastructural studies, in which the ER luminal protein BiP was labeled by immunoperoxidase cytochemistry, revealed that L. pneumophila replication vacuoles resemble nascent autophagosomes. Furthermore, short-term amino acid starvation of macrophages, which stimulated host autophagosomes. Furthermore, short-term amino acid starvation of macrophages, which stimulated host autophagy, increased association of the bacteria with the ER and enhanced bacterial growth. These results are compatible with the hypothesis that L. pneumophila exploits the autophagy machinery of macrophages to establish an intracellular niche favorable for replication. PMID:7642298

  3. 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.

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

    DOE PAGES

    Saberianfar, Reza; Sattarzadeh, Amirali; Joensuu, Jussi J.; ...

    2016-05-23

    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). Here 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 intomore » 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.« less

  5. 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.

  6. 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.

  7. Microtubules and the endoplasmic reticulum are highly interdependent structures

    PubMed Central

    1986-01-01

    The interrelationships of the endoplasmic reticulum (ER), microtubules, and intermediate filaments were studied in the peripheral regions of thin, spread fibroblasts, epithelial, and vascular endothelial cells in culture. We combined a fluorescent dye staining technique to localize the ER with immunofluorescence to localize microtubules or intermediate filaments in the same cell. Microtubules and the ER are sparse in the lamellipodia, but intermediate filaments are usually completely absent. These relationships indicate that microtubules and the ER advance into the lamellipodia before intermediate filaments. We observed that microtubules and tubules of the ER have nearly identical distributions in lamellipodia, where new extensions of both are taking place. We perturbed microtubules by nocodazole, cold temperature, or hypotonic shock, and observed the effects on the ER distribution. On the basis of our observations in untreated cells and our experiments with microtubule perturbation, we conclude that microtubules and the ER are highly interdependent in two ways: (a) polymerization of individual microtubules and extension of individual ER tubules occur together at the level of resolution of the fluorescence microscope, and (b) depolymerization of microtubules does not disrupt the ER network in the short term (15 min), but prolonged absence of microtubules (2 h) leads to a slow retraction of the ER network towards the cell center, indicating that over longer periods of time, the extended state of the entire ER network requires the microtubule system. PMID:3533956

  8. 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.

  9. Apoptosis, autophagy & endoplasmic reticulum stress in diabetes mellitus.

    PubMed

    Demirtas, Levent; Guclu, Aydin; Erdur, Fatih Mehmet; Akbas, Emin Murat; Ozcicek, Adalet; Onk, Didem; Turkmen, Kultigin

    2016-10-01

    The prevalence of diabetes mellitus (DM) is increasing secondary to increased consumption of food and decreased physical activity worldwide. Hyperglycaemia, insulin resistance and hypertrophy of pancreatic beta cells occur in the early phase of diabetes. However, with the progression of diabetes, dysfunction and loss of beta cells occur in both types 1 and 2 DM. Programmed cell death also named apoptosis is found to be associated with diabetes, and apoptosis of beta cells might be the main mechanism of relative insulin deficiency in DM. Autophagic cell death and apoptosis are not entirely distinct programmed cell death mechanisms and share many of the regulator proteins. These processes can occur in both physiologic and pathologic conditions including DM. Besides these two important pathways, endoplasmic reticulum (ER) also acts as a cell sensor to monitor and maintain cellular homeostasis. ER stress has been found to be associated with autophagy and apoptosis. This review was aimed to describe the interactions between apoptosis, autophagy and ER stress pathways in DM.

  10. Endoplasmic Reticulum Stress Interacts With Inflammation in Human Diseases.

    PubMed

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

    2016-02-01

    The endoplasmic reticulum (ER) is a critical organelle for normal cell function and homeostasis. Disturbance in the 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 the type of 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, infectious, neurodegenerative, 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 have been 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 poorly understood. Further understanding of the biochemistry, cell biology, and physiology may enable the development of novel therapies that spontaneously target these pathogenic pathways.

  11. 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

  12. Methods to Study PTEN in Mitochondria and Endoplasmic Reticulum.

    PubMed

    Missiroli, Sonia; Morganti, Claudia; Giorgi, Carlotta; Pinton, Paolo

    2016-01-01

    Although PTEN has been widely described as a nuclear and cytosolic protein, in the last 2 years, alternative organelles, such as the endoplasmic reticulum (ER), pure mitochondria, and mitochondria-associated membranes (MAMs), have been recognized as pivotal targets of PTEN activity.Here, we describe different methods that have been used to highlight PTEN subcellular localization.First, a protocol to extract nuclear and cytosolic fractions has been described to assess the "canonical" PTEN localization. Moreover, we describe a protocol for mitochondria isolation with proteinase K (PK) to further discriminate whether PTEN associates with the outer mitochondrial membrane (OMM) or resides within the mitochondria. Finally, we focus our attention on a subcellular fractionation protocol of cells that permits the isolation of MAMs containing unique regions of ER membranes attached to the outer mitochondrial membrane (OMM) and mitochondria without contamination from other organelles. In addition to biochemical fractionations, immunostaining can be used to determine the subcellular localization of proteins; thus, a detailed protocol to obtain good immunofluorescence (IF) is described. The employment of these methodological approaches could facilitate the identification of different PTEN localizations in several physiopathological contexts.

  13. Live cell imaging of protein dislocation from the endoplasmic reticulum.

    PubMed

    Zhong, Yongwang; Fang, Shengyun

    2012-08-10

    Misfolded proteins in the endoplasmic reticulum (ER) are dislocated to the cytosol to be degraded by the proteasomes. Various plant and bacterial toxins and certain viruses hijack this dislocation pathway to exert their toxicity or to infect cells. In this study, we report a dislocation-dependent reconstituted GFP (drGFP) assay that allows, for the first time, imaging proteins dislocated from the ER lumen to the cytosol in living cells. Our results indicate that both luminal and membrane-spanning ER proteins can be fully dislocated from the ER to the cytosol. By combining the drGFP assay with RNAi or chemical inhibitors of proteins in the Hrd1 ubiquitin ligase complex, we demonstrate that the Sel1L, Hrd1, p97/VCP, and importin β proteins are required for the dislocation of misfolded luminal α-1 antitrypsin. The strategy described in this work is broadly applicable to the study of other types of transmembrane transport of proteins and likely also of viruses and toxins in living cells.

  14. Small GTPases and Brucella entry into the endoplasmic reticulum.

    PubMed

    de Bolle, Xavier; Letesson, Jean-Jacques; Gorvel, Jean-Pierre

    2012-12-01

    A key determinant for intracellular pathogenic bacteria to ensure their virulence within host cells is their ability to bypass the endocytic pathway and to reach a safe niche of replication. In the case of Brucella, the bacterium targets the ER (endoplasmic reticulum) to create a replicating niche called the BCV (Brucella-containing vacuole). The ER is a suitable strategic place for pathogenic Brucella. Indeed, bacteria can be hidden from host cell defences to persist within the host, and they can take advantage of the membrane reservoir delivered by the ER to replicate. Interaction with the ER leads to the presence on the BCV of the GAPDH (glyceraldehyde-3-phosphate dehydrogenase) and the small GTPase Rab2 known to be located on secretory vesicles that traffic between the ER and the Golgi apparatus. GAPDH and the small GTPase Rab2 controls Brucella replication at late times post-infection. A specific interaction between the human small GTPase Rab2 and a Brucella spp. protein named RicA was identified. Altered kinetics of intracellular trafficking and faster proliferation of the Brucella abortus ΔricA mutant was observed compared with the wild-type strain. RicA is the first reported effector with a proposed function for B. abortus.

  15. Chlorpyrifos induces endoplasmic reticulum stress in JEG-3 cells.

    PubMed

    Reyna, Luciana; Flores-Martín, Jésica; Ridano, Magali E; Panzetta-Dutari, Graciela M; Genti-Raimondi, Susana

    2017-04-01

    Chlorpyrifos (CPF) is an organophosphorous pesticide widely used in agricultural, industrial, and household applications. We have previously shown that JEG-3 cells are able to attenuate the oxidative stress induced by CPF through the adaptive activation of the Nrf2/ARE pathway. Considering that there is a relationship between oxidative stress and endoplasmic reticulum stress (ER), herein we investigated whether CPF also induces ER stress in JEG-3 cells. Cells were exposed to 50μM or 100μM CPF during 24h in conditions where cell viability was not altered. Western blot and PCR assays were used to explore the protein and mRNA levels of ER stress biomarkers, respectively. CPF induced an increase of the typical ER stress-related proteins, such as GRP78/BiP and IRE1α, a sensor for the unfolded protein response, as well as in phospho-eIF2α and XBP1 mRNA splicing. Additionally, CPF led to a decrease in p53 protein expression. The downregulation of p53 levels induced by CPF was partially blocked when cells were exposed to CPF in the presence of the proteasome inhibitor MG132. Altogether, these findings point out that CPF induces ER stress in JEG-3 cells; however these cells are able to attenuate it downregulating the levels of the pro-apoptotic protein p53.

  16. Thiamine Deficiency Induces Endoplasmic Reticulum Stress in Neurons

    PubMed Central

    Wang, Xin; Wang, Bingwei; Fan, Zhiqin; Shi, Xianglin; Ke, Zun-Ji; Luo, Jia

    2007-01-01

    Thiamine (vitamin B1) deficiency (TD) causes region selective neuronal loss in the brain; it has been used to model neurodegeneration that accompanies mild impairment of oxidative metabolism. The mechanisms for TD-induced neurodegeneration remain incompletely elucidated. Inhibition of protein glycosylation, perturbation of calcium homeostasis and reduction of disulfide bonds provoke the accumulation of unfolded proteins in the endoplasmic reticulum (ER), and cause ER stress. Recently, ER stress has been implicated in a number of neurodegenerative models. We demonstrated here that TD up-regulated several markers of ER stress, such as GRP78, GADD153/Chop, phosphorylation of eIF2α and cleavage of caspase-12 in the cerebellum and the thalamus of mice. Furthermore, ultrastructural analysis by electron microscopic study revealed an abnormality in ER structure. To establish an in vitro model of TD in neurons, we treated cultured cerebellar granule neurons (CGNs) with amprolium, a potent inhibitor of thiamine transport. Exposure to amprolium caused apoptosis and the generation of reactive oxygen species in CGNs. Similar to the observation in vivo, TD up-regulated markers for ER stress. Treatment of a selective inhibitor of caspase-12 significantly alleviated amprolium-induced death of CGNs. Thus, ER stress may play a role in TD-induced brain damage. PMID:17137721

  17. Thiamine deficiency induces endoplasmic reticulum stress in neurons.

    PubMed

    Wang, X; Wang, B; Fan, Z; Shi, X; Ke, Z-J; Luo, J

    2007-02-09

    Thiamine (vitamin B1) deficiency (TD) causes region selective neuronal loss in the brain; it has been used to model neurodegeneration that accompanies mild impairment of oxidative metabolism. The mechanisms for TD-induced neurodegeneration remain incompletely elucidated. Inhibition of protein glycosylation, perturbation of calcium homeostasis and reduction of disulfide bonds provoke the accumulation of unfolded proteins in the endoplasmic reticulum (ER), and cause ER stress. Recently, ER stress has been implicated in a number of neurodegenerative models. We demonstrated here that TD up-regulated several markers of ER stress, such as glucose-regulated protein (GRP) 78, growth arrest and DNA-damage inducible protein or C/EBP-homologus protein (GADD153/Chop), phosphorylation of eIF2alpha and cleavage of caspase-12 in the cerebellum and the thalamus of mice. Furthermore, ultrastructural analysis by electron microscopic study revealed an abnormality in ER structure. To establish an in vitro model of TD in neurons, we treated cultured cerebellar granule neurons (CGNs) with amprolium, a potent inhibitor of thiamine transport. Exposure to amprolium caused apoptosis and the generation of reactive oxygen species in CGNs. Similar to the observation in vivo, TD up-regulated markers for ER stress. Treatment of a selective inhibitor of caspase-12 significantly alleviated amprolium-induced death of CGNs. Thus, ER stress may play a role in TD-induced brain damage.

  18. Arachidonoyl-Specific Diacylglycerol Kinase ε and the Endoplasmic Reticulum

    PubMed Central

    Nakano, Tomoyuki; Matsui, Hirooki; Tanaka, Toshiaki; Hozumi, Yasukazu; Iseki, Ken; Kawamae, Kaneyuki; Goto, Kaoru

    2016-01-01

    The endoplasmic reticulum (ER) comprises an interconnected membrane network, which is made up of lipid bilayer and associated proteins. This organelle plays a central role in the protein synthesis and sorting. In addition, it represents the synthetic machinery of phospholipids, the major constituents of the biological membrane. In this process, phosphatidic acid (PA) serves as a precursor of all phospholipids, suggesting that PA synthetic activity is closely associated with the ER function. One enzyme responsible for PA synthesis is diacylglycerol kinase (DGK) that phosphorylates diacylglycerol (DG) to PA. DGK is composed of a family of enzymes with distinct features assigned to each isozyme in terms of structure, enzymology, and subcellular localization. Of DGKs, DGKε uniquely exhibits substrate specificity toward arachidonate-containing DG and is shown to reside in the ER. Arachidonic acid, a precursor of bioactive eicosanoids, is usually acylated at the sn-2 position of phospholipids, being especially enriched in phosphoinositide. In this review, we focus on arachidonoyl-specific DGKε with respect to the historical context, molecular basis of the substrate specificity and ER-targeting, and functional implications in the ER. PMID:27917381

  19. The effect of calcitriol on endoplasmic reticulum stress response.

    PubMed

    Haddur, Ela; Ozkaya, Ali Burak; Ak, Handan; Aydin, Hikmet Hakan

    2015-06-01

    Calcitriol, the active form of vitamin D, is known for its anticancer properties including induction of apoptosis, inhibition of angiogenesis, and metastasis. Calcitriol also increases intracellular calcium triggering apoptosis in a calpain-dependent manner. Since the main storage unit for cellular calcium is endoplasmic reticulum (ER) and a decrease in ER calcium levels might induce ER stress associated cell death, we hypothesized that the cellular actions of calcitriol occur via ER stress. We have evaluated induction of ER stress by assessing BIP expression and XBP-1 splicing in breast cancer cell lines (MCF-7 and MDA-MB-231) and mammary epithelial cell line MCF10A. Our results suggest that cytotoxic concentrations of calcitriol induce an ER stress related response indicated as increased BIP levels and XBP-1 splicing not only in breast cancer cells but also in mammary epithelial cell line. However, vehicle treatment also induced a similar response de-emphasizing the importance of such effect. Calcitriol also failed to activate calpains, further weakening the idea of ER stress as the main mechanism for apoptotic effects of calcitriol. Taken together our results suggest an association between ER stress and vitamin D signaling. However present data indicates that ER stress by itself is not sufficient to explain anticancer properties of calcitriol.

  20. Endoplasmic reticulum-mitochondria calcium signaling in hepatic metabolic diseases.

    PubMed

    Rieusset, Jennifer

    2017-06-01

    The liver plays a central role in glucose homeostasis, and both metabolic inflexibility and insulin resistance predispose to the development of hepatic metabolic diseases. Mitochondria and endoplasmic reticulum (ER), which play a key role in the control of hepatic metabolism, also interact at contact points defined as mitochondria-associated membranes (MAM), in order to exchange metabolites and calcium (Ca(2+)) and regulate cellular homeostasis and signaling. Here, we overview the role of the liver in the control of glucose homeostasis, mainly focusing on the independent involvement of mitochondria, ER and Ca(2+) signaling in both healthy and pathological contexts. Then we focus on recent data highlighting MAM as important hubs for hormone and nutrient signaling in the liver, thus adapting mitochondria physiology and cellular metabolism to energy availability. Lastly, we discuss how chronic ER-mitochondria miscommunication could participate to hepatic metabolic diseases, pointing MAM interface as a potential therapeutic target for metabolic disorders. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Endoplasmic reticulum-mitochondria junction is required for iron homeostasis.

    PubMed

    Xue, Yong; Schmollinger, Stefan; Attar, Narsis; Campos, Oscar A; Vogelauer, Maria; Carey, Michael F; Merchant, Sabeeha S; Kurdistani, Siavash K

    2017-08-11

    The endoplasmic reticulum (ER)-mitochondria encounter structure (ERMES) is a protein complex that physically tethers the two organelles to each other and creates the physical basis for communication between them. ERMES functions in lipid exchange between the ER and mitochondria, protein import into mitochondria, and maintenance of mitochondrial morphology and genome. Here, we report that ERMES is also required for iron homeostasis. Loss of ERMES components activates an Aft1-dependent iron deficiency response even in iron-replete conditions, leading to accumulation of excess iron inside the cell. This function is independent of known ERMES roles in calcium regulation, phospholipid biosynthesis, or effects on mitochondrial morphology. A mutation in the vacuolar protein sorting 13 (VPS13) gene that rescues the glycolytic phenotype of ERMES mutants suppresses the iron deficiency response and iron accumulation. Our findings reveal that proper communication between the ER and mitochondria is required for appropriate maintenance of cellular iron levels. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

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

    PubMed

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

    2006-06-02

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

  3. 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.

  4. Protein misfolding and endoplasmic reticulum stress in chronic lung disease.

    PubMed

    Wei, James; Rahman, Sadaf; Ayaub, Ehab A; Dickhout, Jeffrey G; Ask, Kjetil

    2013-04-01

    The pathogenesis of chronic lung disorders is poorly understood but is often thought to arise because of repeated injuries derived from exposure to exogenous or endogenous stress factors. Protein-misfolding events have been observed in a variety of genetic and nongenetic chronic lung disorders and may contribute to both the initiation and the progression of lung disease through endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR). Evidence indicates that exposure to common lung irritants such as cigarette smoke, environmental pollutants, and infectious viral or bacterial agents can induce ER stress and protein misfolding. Although the UPR is thought to be a molecular mechanism involved in the repair and restoration of protein homeostasis or "proteostasis," prolonged activation of the UPR may lead to compromised cellular functions, cellular transformation, or cell death. Here, we review literature that associates protein-misfolding events with ER stress and UPR activation and discuss how this basic molecular repair mechanism may contribute to the initiation and progression of various genetic and nongenetic chronic lung diseases.

  5. Protein quality control, retention, and degradation at the endoplasmic reticulum.

    PubMed

    Benyair, Ron; Ron, Efrat; Lederkremer, Gerardo Z

    2011-01-01

    In order to maintain proper cellular functions, all living cells, from bacteria to mammalian cells, must carry out a rigorous quality control process in which nascent and newly synthesized proteins are examined. An important role of this process is to protect cells against pathological accumulation of unfolded and misfolded proteins. The endoplasmic reticulum (ER) has evolved as a staging ground for secretory protein synthesis with distinct sites for entry, quality control, and exit. In the ER, most proteins are N-glycosylated, a posttranslational modification that defines the quality control pathway that the protein will undergo. The folding state of glycoproteins is revealed by specific modifications of their N-glycans. Regardless of size and posttranslational modifications, the folding states of all proteins must be identified as unfolded, properly folded, or terminally misfolded and accordingly subjected to ER retention and continued folding attempts, export and maturation, or retrotranslocation to the cytosol for degradation. These processes involve specialized machineries that utilize molecular chaperones, protein- and N-glycan-modifying enzymes, and lectins for protein folding and quality control and ubiquitination and degradation machineries for disposal. All these machineries are regulated by a signaling pathway, the unfolded protein response, which upregulates ER functions when under the stress of high protein load. Here, we describe the molecular mechanisms that are implicated and discuss recent data that underline the importance of compartmentalization in the segregation of the various functions of the ER for their correct function.

  6. Selective export of autotaxin from the endoplasmic reticulum.

    PubMed

    Lyu, Lin; Wang, Baolu; Xiong, Chaoyang; Zhang, Xiaotian; Zhang, Xiaoyan; Zhang, Junjie

    2017-04-28

    Autotaxin (ATX) or ectonucleotide pyrophosphatase/phosphodiesterase 2 (ENPP2) is a secretory glycoprotein and functions as the key enzyme for lysophosphatidic acid generation. The mechanism of ATX protein trafficking is largely unknown. Here, we demonstrated that p23, a member of the p24 protein family, was the protein-sorting receptor required for endoplasmic reticulum (ER) export of ATX. A di-phenylalanine (Phe-838/Phe-839) motif in the human ATX C-terminal region was identified as a transport signal essential for the ATX-p23 interaction. Knockdown of individual Sec24 isoforms by siRNA revealed that ER export of ATX was impaired only if Sec24C was down-regulated. These results suggest that ATX is selectively exported from the ER through a p23, Sec24C-dependent pathway. In addition, it was found that AKT signaling played a role in ATX secretion regulation to facilitate ATX ER export by enhancing the nuclear factor of activated T cell-mediated p23 expression. Furthermore, the di-hydrophobic amino acid motifs (FY) also existed in the C-terminal regions of human ENPP1 and ENPP3. Such a p23, Sec24C-dependent selective ER export mechanism is conserved among these ENPP family members. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Causes and consequences of endoplasmic reticulum stress in rheumatic disease.

    PubMed

    Navid, Fatemeh; Colbert, Robert A

    2017-01-01

    Rheumatic diseases represent a heterogeneous group of inflammatory conditions, many of which involve chronic activation of both innate and adaptive immune responses by multiple genetic and environmental factors. These immune responses involve the secretion of excessive amounts of cytokines and other signalling mediators by activated immune cells. The endoplasmic reticulum (ER) is the cellular organelle that directs the folding, processing and trafficking of membrane-bound and secreted proteins, including many key components of the immune response. Maintaining homeostasis in the ER is critical to cell function and survival. Consequently, elaborate mechanisms have evolved to sense and respond to ER stress through three main signalling pathways that together comprise the unfolded protein response (UPR). Activation of the UPR can rapidly resolve the accumulation of misfolded proteins, direct permanent changes in the size and function of cells during differentiation, and critically influence the immune response and inflammation. Recognition of the importance of ER stress and UPR signalling pathways in normal and dysregulated immune responses has greatly increased in the past few years. This Review discusses several settings in which ER stress contributes to the pathogenesis of rheumatic diseases and considers some of the therapeutic opportunities that these discoveries provide.

  8. Endoplasmic Reticulum Stress, Unfolded Protein Response, and Cancer Cell Fate

    PubMed Central

    Corazzari, Marco; Gagliardi, Mara; Fimia, Gian Maria; Piacentini, Mauro

    2017-01-01

    Perturbation of endoplasmic reticulum (ER) homeostasis results in a stress condition termed “ER stress” determining the activation of a finely regulated program defined as unfolded protein response (UPR) and whose primary aim is to restore this organelle’s physiological activity. Several physiological and pathological stimuli deregulate normal ER activity causing UPR activation, such as hypoxia, glucose shortage, genome instability, and cytotoxic compounds administration. Some of these stimuli are frequently observed during uncontrolled proliferation of transformed cells, resulting in tumor core formation and stage progression. Therefore, it is not surprising that ER stress is usually induced during solid tumor development and stage progression, becoming an hallmark of such malignancies. Several UPR components are in fact deregulated in different tumor types, and accumulating data indicate their active involvement in tumor development/progression. However, although the UPR program is primarily a pro-survival process, sustained and/or prolonged stress may result in cell death induction. Therefore, understanding the mechanism(s) regulating the cell survival/death decision under ER stress condition may be crucial in order to specifically target tumor cells and possibly circumvent or overcome tumor resistance to therapies. In this review, we discuss the role played by the UPR program in tumor initiation, progression and resistance to therapy, highlighting the recent advances that have improved our understanding of the molecular mechanisms that regulate the survival/death switch. PMID:28491820

  9. MITOL regulates endoplasmic reticulum-mitochondria contacts via Mitofusin2.

    PubMed

    Sugiura, Ayumu; Nagashima, Shun; Tokuyama, Takeshi; Amo, Taku; Matsuki, Yohei; Ishido, Satoshi; Kudo, Yoshihisa; McBride, Heidi M; Fukuda, Toshifumi; Matsushita, Nobuko; Inatome, Ryoko; Yanagi, Shigeru

    2013-07-11

    The mitochondrial ubiquitin ligase MITOL regulates mitochondrial dynamics. We report here that MITOL regulates mitochondria-associated endoplasmic reticulum (ER) membrane (MAM) domain formation through mitofusin2 (Mfn2). MITOL interacts with and ubiquitinates mitochondrial Mfn2, but not ER-associated Mfn2. Mutation analysis identified a specific interaction between MITOL C-terminal domain and Mfn2 HR1 domain. MITOL mediated lysine-63-linked polyubiquitin chain addition to Mfn2, but not its proteasomal degradation. MITOL knockdown inhibited Mfn2 complex formation and caused Mfn2 mislocalization and MAM dysfunction. Sucrose-density gradient centrifugation and blue native PAGE retardation assay demonstrated that MITOL is required for GTP-dependent Mfn2 oligomerization. MITOL knockdown reduced Mfn2 GTP binding, resulting in reduced GTP hydrolysis. We identified K192 in the GTPase domain of Mfn2 as a major ubiquitination site for MITOL. A K192R mutation blocked oligomerization even in the presence of GTP. Taken together, these results suggested that MITOL regulates ER tethering to mitochondria by activating Mfn2 via K192 ubiquitination. Copyright © 2013 Elsevier Inc. All rights reserved.

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

    SciTech Connect

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

    2016-05-23

    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). Here 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.

  11. Coping with endoplasmic reticulum stress in the cardiovascular system.

    PubMed

    Groenendyk, Jody; Agellon, Luis B; Michalak, Marek

    2013-01-01

    The endoplasmic reticulum (ER) is a multifunctional intracellular organelle, a component of the cellular reticular network that allows cells to adjust to a wide variety of conditions. The cardiomyocyte reticular network is the ideal location of sensors for both intrinsic and extrinsic factors that disrupt energy and/or nutrient homeostasis and lead to ER stress, a disturbance in ER function. ER stress has been linked to both physiological and pathological states in the cardiovascular system; such states include myocardial infarction, oxygen starvation (hypoxia) and fuel starvation, ischemia, pressure overload, dilated cardiomyopathy, hypertrophy, and heart failure. The ER stress coping response (e.g., the unfolded protein response) is composed of discrete pathways that are controlled by a collection of common regulatory components that may function as a single entity involved in reacting to ER stress. These corrective strategies allow the cardiomyocyte reticular network to restore energy and/or nutrient homeostasis and to avoid cell death. Therefore, the identities of the ER stress corrective strategies are important targets for the development of therapeutic approaches for cardiovascular and other acquired disorders.

  12. 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

  13. 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

  14. Aging induced endoplasmic reticulum stress alters sleep and sleep homeostasis.

    PubMed

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

    2014-06-01

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

  15. PROTEOMICS ANALYSIS OF ROUGH ENDOPLASMIC RETICULUM IN PANCREATIC BETA CELLS

    PubMed Central

    Lee, Jin-sook; Wu, Yanning; Skallos, Patracia; Fang, Jingye; Zhang, Xuebao; Karnovsky, Alla; Woods, James; Stemmer, Paul M.; Liu, Ming; Zhang, Kezhong; Chen, Xuequn

    2015-01-01

    Pancreatic beta cells have well-developed endoplasmic reticulum (ER) to accommodate for the massive production and secretion of insulin. ER homeostasis is vital for normal beta cell function. Perturbation of ER homeostasis contributes to beta cell dysfunction in both type 1 and type 2 diabetes. To systematically identify the molecular machinery responsible for proinsulin biogenesis and maintenance of beta cell ER homeostasis, a widely used mouse pancreatic beta cell line, MIN6 cell was used to purify rough ER. Two different purification schemes were utilized. In each experiment, the ER pellets were solubilized and analyzed by one dimensional SDS-PAGE coupled with HPLC-MS/MS. A total of 1467 proteins were identified in three experiments with ≥95% confidence, among which 1117 proteins were found in at least two separate experiments and 737 proteins found in all three experiments. Gene ontology analysis revealed a comprehensive profile of known and novel players responsible for proinsulin biogenesis and ER homeostasis. Further bioinformatics analysis also identified potential beta cell specific ER proteins as well as ER proteins present in the risk genetic loci of type 2 diabetes. This dataset defines a molecular environment in the ER for proinsulin synthesis, folding and export and laid a solid foundation for further characterizations of altered ER homeostasis under diabetes-causing conditions. PMID:25546123

  16. PERK-opathies: An Endoplasmic Reticulum Stress Mechanism Underlying Neurodegeneration.

    PubMed

    Bell, Michelle C; Meier, Shelby E; Ingram, Alexandria L; Abisambra, Jose F

    2016-01-01

    The unfolded protein response (UPR) plays a vital role in maintaining cell homeostasis as a consequence of endoplasmic reticulum (ER) stress. However, prolonged UPR activity leads to cell death. This time-dependent dual functionality of the UPR represents the adaptive and cytotoxic pathways that result from ER stress. Chronic UPR activation in systemic and neurodegenerative diseases has been identified as an early sign of cellular dyshomeostasis. The Protein Kinase R-like ER Kinase (PERK) pathway is one of three major branches in the UPR, and it is the only one to modulate protein synthesis as an adaptive response. The specific identification of prolonged PERK activity has been correlated with the progression of disorders such as diabetes, Alzheimer's disease, and cancer, suggesting that PERK plays a role in the pathology of these disorders. For the first time, the term "PERK-opathies" is used to group these diseases in which PERK mediates detriment to the cell culminating in chronic disorders. This article reviews the literature documenting links between systemic disorders with the UPR, but with a specific emphasis on the PERK pathway. Then, articles reporting links between the UPR, and more specifically PERK, and neurodegenerative disorders are presented. Finally, a therapeutic perspective is discussed, where PERK interventions could be potential remedies for cellular dysfunction in chronic neurodegenerative disorders.

  17. Melatonin inhibits autophagy and endoplasmic reticulum stress in mice with carbon tetrachloride-induced fibrosis.

    PubMed

    San-Miguel, Beatriz; Crespo, Irene; Sánchez, Diana I; González-Fernández, Bárbara; Ortiz de Urbina, Juan J; Tuñón, María J; González-Gallego, Javier

    2015-09-01

    This study aimed to investigate whether inhibition of autophagy and endoplasmic reticulum (ER stress) associates with the antifibrogenic effect of melatonin in mice treated with carbon tetrachloride (CCl4 ). Mice received CCl4 5 μL/g body wt i.p. twice a week for 4 wk or 6 wk. Melatonin was given at 5 or 10 mg/kg/day i.p, beginning 2 wk after the start of CCl4 administration. Treatment with CCl4 resulted in fibrosis evidenced by the staining of α-smooth muscle actin (α-SMA)-positive cells. CCl4 induced an autophagic response measured as the presence of autophagic vesicles, protein 1 light chain 3 (LC3) staining, conversion of LC3-I to autophagosome-associated LC3-II, changes in expression of beclin-1, UV radiation resistance-associated gene (UVRAG), ubiquitin-like autophagy-related (Atg5), Atg12, Atg16L1, sequestosome 1 (p62/SQSTM1), and lysosome-associated membrane protein (LAMP)-2, and increased phosphorylation of the mammalian target of rapamycin (mTOR). There was an increase in the expression of the ER stress chaperones CCAAT/enhancer-binding protein homologous protein (CHOP), immunoglobulin-heavy-chain-binding protein (BiP/GRP78), and 94-kDa glucose-regulated protein (GRP94), and in the mRNA levels of pancreatic ER kinase (PERK), activating transcription factor 6 (ATF6), ATF4, inositol-requiring enzyme 1 (IRE1), and spliced X-box-binding protein-1 (XBP1). Phospho-IRE1, ATF6, and phospho-PERK protein concentration also increased significantly. Immunohistochemical staining of α-SMA indicated an abrogation of hepatic stellate cells activation by melatonin. Furthermore, treatment with the indole resulted in significant inhibition of the autophagic flux and the unfolded protein response. Findings from this study give new insight into molecular pathways accounting for the protective effect of melatonin in fibrogenesis. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. NUMERICAL CONVERGENCE IN SMOOTHED PARTICLE HYDRODYNAMICS

    SciTech Connect

    Zhu, Qirong; Li, Yuexing; Hernquist, Lars

    2015-02-10

    We study the convergence properties of smoothed particle hydrodynamics (SPH) using numerical tests and simple analytic considerations. Our analysis shows that formal numerical convergence is possible in SPH only in the joint limit N → ∞, h → 0, and N{sub nb} → ∞, where N is the total number of particles, h is the smoothing length, and N{sub nb} is the number of neighbor particles within the smoothing volume used to compute smoothed estimates. Previous work has generally assumed that the conditions N → ∞ and h → 0 are sufficient to achieve convergence, while holding N{sub nb} fixed. We demonstrate that if N{sub nb} is held fixed as the resolution is increased, there will be a residual source of error that does not vanish as N → ∞ and h → 0. Formal numerical convergence in SPH is possible only if N{sub nb} is increased systematically as the resolution is improved. Using analytic arguments, we derive an optimal compromise scaling for N{sub nb} by requiring that this source of error balance that present in the smoothing procedure. For typical choices of the smoothing kernel, we find N{sub nb} ∝N {sup 0.5}. This means that if SPH is to be used as a numerically convergent method, the required computational cost does not scale with particle number as O(N), but rather as O(N {sup 1} {sup +} {sup δ}), where δ ≈ 0.5, with a weak dependence on the form of the smoothing kernel.

  19. Nonequilibrium flows with smooth particle applied mechanics

    SciTech Connect

    Kum, Oyeon

    1995-07-01

    Smooth particle methods are relatively new methods for simulating solid and fluid flows through they have a 20-year history of solving complex hydrodynamic problems in astrophysics, such as colliding planets and stars, for which correct answers are unknown. The results presented in this thesis evaluate the adaptability or fitness of the method for typical hydrocode production problems. For finite hydrodynamic systems, boundary conditions are important. A reflective boundary condition with image particles is a good way to prevent a density anomaly at the boundary and to keep the fluxes continuous there. Boundary values of temperature and velocity can be separately controlled. The gradient algorithm, based on differentiating the smooth particle expression for (uρ) and (Tρ), does not show numerical instabilities for the stress tensor and heat flux vector quantities which require second derivatives in space when Fourier`s heat-flow law and Newton`s viscous force law are used. Smooth particle methods show an interesting parallel linking to them to molecular dynamics. For the inviscid Euler equation, with an isentropic ideal gas equation of state, the smooth particle algorithm generates trajectories isomorphic to those generated by molecular dynamics. The shear moduli were evaluated based on molecular dynamics calculations for the three weighting functions, B spline, Lucy, and Cusp functions. The accuracy and applicability of the methods were estimated by comparing a set of smooth particle Rayleigh-Benard problems, all in the laminar regime, to corresponding highly-accurate grid-based numerical solutions of continuum equations. Both transient and stationary smooth particle solutions reproduce the grid-based data with velocity errors on the order of 5%. The smooth particle method still provides robust solutions at high Rayleigh number where grid-based methods fails.

  20. Endoplasmic reticulum-Golgi intermediate compartment protein 3 knockdown suppresses lung cancer through endoplasmic reticulum stress-induced autophagy.

    PubMed

    Hong, Seong-Ho; Chang, Seung-Hee; Cho, Kyung-Cho; Kim, Sanghwa; Park, Sungjin; Lee, Ah Young; Jiang, Hu-Lin; Kim, Hyeon-Jeong; Lee, Somin; Yu, Kyeong-Nam; Seo, Hwi Won; Chae, Chanhee; Kim, Kwang Pyo; Park, Jongsun; Cho, Myung-Haing

    2016-10-04

    Trafficking from the endoplasmic reticulum (ER) to the Golgi apparatus is elevated in cancer cells. Therefore, proteins of the ER-Golgi intermediate compartment (ERGIC) attract significant attention as targets for cancer treatment. Enhanced cancer cell growth and epithelial-mesenchymal transition by ERGICs correlates with poor-prognosis of lung cancer. This prompted us to assess whether knockdown of ERGIC3 may decrease lung cancer growth. To test the hypothesis, the effects of ERGIC3 short hairpin RNA (shERGIC3) on ER stress-induced cell death and lung tumorigenesis were investigated both in vitro and in vivo. Knockdown of ERGIC3 led to ER stress-induced autophagic cell death and suppression of proliferation in the A549 human lung cancer cell-line. Moreover, non-invasive aerosol-delivery of shERGIC3 using the biocompatible carrier glycerol propoxylate triacrylate and spermine (GPT-SPE) inhibited lung tumorigenesis in the K-rasLA1 murine model of lung cancer. Our data suggest that suppression of ERGIC3 could provide a framework for the development of effective lung cancer therapies.