Science.gov

Sample records for elements mediate protection

  1. Essential Elements of Child Protection Mediation.

    ERIC Educational Resources Information Center

    Barsky, Allan Edward

    This study investigated the effectiveness of the process of mediation in child protection (CP) and the essential aspects which may contribute to developing more effective working relationships with child welfare families. The study focused on neutrality, one of the primary aspects of CP mediation. Interviews were conducted with 17 adult family…

  2. Lightning protection for shuttle propulsion elements

    NASA Technical Reports Server (NTRS)

    Goodloe, Carolyn C.; Giudici, Robert J.

    1991-01-01

    The results of lightning protection analyses and tests are weighed against the present set of waivers to the NASA lightning protection specification. The significant analyses and tests are contrasted with the release of a new and more realistic lightning protection specification, in September 1990, that resulted in an inordinate number of waivers. A variety of lightning protection analyses and tests of the Shuttle propulsion elements, the Solid Rocket Booster, the External Tank, and the Space Shuttle Main Engine, were conducted. These tests range from the sensitivity of solid propellant during shipping to penetration of cryogenic tanks during flight. The Shuttle propulsion elements have the capability to survive certain levels of lightning strikes at certain times during transportation, launch site operations, and flight. Changes are being evaluated that may improve the odds of withstanding a major lightning strike. The Solid Rocket Booster is the most likely propulsion element to survive if systems tunnel bond straps are improved. Wiring improvements were already incorporated and major protection tests were conducted. The External Tank remains vulnerable to burn-through penetration of its skin. Proposed design improvements include the use of a composite nose cone and conductive or laminated thermal protection system coatings.

  3. Adenovirus-mediated brain-derived neurotrophic factor expression regulated by hypoxia response element protects brain from injury of transient middle cerebral artery occlusion in mice.

    PubMed

    Shi, Qindong; Zhang, Pengbo; Zhang, Junfeng; Chen, Xinlin; Lu, Haixia; Tian, Yumei; Parker, T L; Liu, Yong

    2009-11-20

    Some gene expression may be regulated by hypoxia-responsive element (HRE) that is bound by hypoxia-inducible factor-1 (HIF-1) which is up-regulated during cerebral ischemia. To explore ischemia/hypoxia-controlled expression and the neuroprotective effects of brain-derived neurotrophic factor (BDNF) after ischemic brain injury, an adenoviral vector using five copies of hypoxia response element (HRE) in the vascular endothelial growth factor gene to regulate the expression of BDNF gene (Ad5HRE:BDNF) was constructed, and its efficacy was verified for driving BDNF expression in cultured Hela cells under hypoxic condition by ELISA. We found that the concentration of BDNF in the Ad5HRE:BDNF-transfected culture media was 28-fold greater in a hypoxic condition than under normoxia. To examine the effect of Ad5HRE:BDNF on ischemic brain injury in vivo, Ad5HRE:BDNF was injected into right caudate putamen of adult mice 7 days prior to 60 min transient middle cerebral artery occlusion (MCAO). It was found that exogenous BDNF expression was increased in the Ad5HRE-BDNF-treated group and infarct volume of the Ad5HRE:BDNF-treated group at 3 days after MCAO was significantly smaller than that of vehicle- or AdNull-treated groups. Moreover, Ad5HRE:BDNF injection resulted in significantly improved sensorimotor scores 7 days after MCAO and induced a reduction in the number of Fluoro-Jade B-positive neurons and TUNEL-positive cells, compared with vehicle- or AdNull-injection. Our findings suggest that BDNF expression could be regulated in hypoxia/ischemia condition with five copies of HRE and ameliorates ischemic brain injury in a mouse focal cerebral ischemia model.

  4. RNAi-mediated plant protection against aphids.

    PubMed

    Yu, Xiu-Dao; Liu, Zong-Cai; Huang, Si-Liang; Chen, Zhi-Qin; Sun, Yong-Wei; Duan, Peng-Fei; Ma, You-Zhi; Xia, Lan-Qin

    2016-06-01

    Aphids (Aphididae) are major agricultural pests that cause significant yield losses of crop plants each year by inflicting damage both through the direct effects of feeding and by vectoring harmful plant viruses. Expression of double-stranded RNA (dsRNA) directed against suitable insect target genes in transgenic plants has been shown to give protection against pests through plant-mediated RNA interference (RNAi). Thus, as a potential alternative and effective strategy for insect pest management in agricultural practice, plant-mediated RNAi for aphid control has received close attention in recent years. In this review, the mechanism of RNAi in insects and the so far explored effective RNAi target genes in aphids, their potential applications in the development of transgenic plants for aphid control and the major challenges in this regard are reviewed, and the future prospects of using plant-mediated RNAi for aphid control are discussed. This review is intended to be a helpful insight into the generation of aphid-resistant plants through plant-mediated RNAi strategy. © 2016 Society of Chemical Industry.

  5. Electrostatic dust protection for optical elements

    NASA Astrophysics Data System (ADS)

    Hoenig, S. A.

    1982-02-01

    The application of electrostatic technology to the protection of optical components in earth-mounted and satellite orbital systems has been investigated. Theory and experiment indicate it is quite practical to prevent dust deposition in an earth environment. A mathematical analysis indicates even better results should be obtained in an orbital vehicle.

  6. Planetary protection: elements for cost minimization

    NASA Astrophysics Data System (ADS)

    Debus, Andre

    2003-11-01

    In line with the UN Outer Space Treaty (article IX of the Outer Space Treaty - London/Washington January 27., 1967 -) and with COSPAR recommendations, for ethical, safety and scientific reasons, exploration of the solar system needs to comply with planetary protection constraints in order to avoid extraterrestrial bodies contamination, particularly biological contamination by terrestrial microorganisms. It is also required to protect Earth from an eventual contamination carried by return systems or samples. The search for life in extraterrestrial samples, in situ or in the frame of sample return missions, must be conducted in order to state with the maximum possible confidence, because the discovery or the non-discovery of life in sample has a direct impact on updatations of planetary protection specifications for future missions. This last requirement imposes consequently also for implementation in order to preserve extra terrestrial samples properties, protecting also indirectly exobiological science. These constraints impose to set up unusual requirements for project teams involved in such solar system exploration missions, requirements based on hardware sterilization, sterile integration, organic cleanliness, microbiological and cleanliness control, the use of high reliability system in order to avoid crashs, the definition of specific trajectories and their control, recontamination prevention .... etc. Implementation of such requirements induces costs, difficult to estimate, but which can be important depending on the solar system target and the mission definition (fly-by, orbiter or lander). The cost impact of a planetary protection program could be important if some basic rules are not taken into account enough early and consequently, upon past experience, some recommendations can be proposed here in order to manage properly such programs and to minimize their cost.

  7. [Art-therapy in anorexia: the mediative elements?].

    PubMed

    Jarrige, Maïtè; Calestrémé, Marie; Sudres, Jean-Luc

    2015-01-01

    Art does not have any inherent curative property; it is used as a therapeutic medium. Three mediative elements, depending on their specificities, have a role to play in the intrapsychic and interpersonal transformation of the patient: the creation the art-therapist and the group of participants. This article looks at the different components of art-therapy used in the treatment of anorexia.

  8. Development of boundary element analysis system for corrosion protection design

    SciTech Connect

    Miyasaka, M.; Takayama, H.; Amaya, K.; Aoki, S.

    1997-12-01

    In order to make a practical application of boundary element method (BEM) for quantitative predictions of cathodic protection and macro-cell corrosion, a BEM analysis system based on the 2D, 3D and axi-symmetric programs was developed. The system consists of a polarization curve database and programs to perform element discretization, input file set-up, boundary element analysis and graphic display of input and output data. Even an engineer with no knowledge of corrosion will be able to operate this system easily and perform effective analyses. The usefulness of the system was demonstrated by an application example for the cathodic protection design of a seawater pump. In this system, the effects of flow-rate and time on the polarization curve can be taken into account for defining the boundary conditions.

  9. Nuclease escape elements protect messenger RNA against cleavage by multiple viral endonucleases

    PubMed Central

    Muller, Mandy

    2017-01-01

    During lytic Kaposi’s sarcoma-associated herpesvirus (KSHV) infection, the viral endonu- clease SOX promotes widespread degradation of cytoplasmic messenger RNA (mRNA). However, select mRNAs, including the transcript encoding interleukin-6 (IL-6), escape SOX-induced cleavage. IL-6 escape is mediated through a 3’ UTR RNA regulatory element that overrides the SOX targeting mechanism. Here, we reveal that this protective RNA element functions to broadly restrict cleavage by a range of homologous and non-homologous viral endonucleases. However, it does not impede cleavage by cellular endonucleases. The IL-6 protective sequence may be representative of a larger class of nuclease escape elements, as we identified a similar protective element in the GADD45B mRNA. The IL-6 and GADD45B-derived elements display similarities in their sequence, putative structure, and several associated RNA binding proteins. However, the overall composition of their ribonucleoprotein complexes appears distinct, leading to differences in the breadth of nucleases restricted. These findings highlight how RNA elements can selectively control transcript abundance in the background of widespread virus-induced mRNA degradation. PMID:28841715

  10. RNAi-mediated crop protection against insects.

    PubMed

    Price, Daniel R G; Gatehouse, John A

    2008-07-01

    Downregulation of the expression of specific genes through RNA interference (RNAi), has been widely used for genetic research in insects. The method has relied on the injection of double-stranded RNA (dsRNA), which is not possible for practical applications in crop protection. By contrast, specific suppression of gene expression in nematodes is possible through feeding with dsRNA. This approach was thought to be unfeasible in insects, but recent results have shown that dsRNA fed as a diet component can be effective in downregulating targeted genes. More significantly, expression of dsRNA directed against suitable insect target genes in transgenic plants has been shown to give protection against pests, opening the way for a new generation of insect-resistant crops.

  11. Nitric oxide protects endothelium from cadmium mediated leakiness.

    PubMed

    Nagarajan, Shunmugam; Rajendran, Saranya; Saran, Uttara; Priya, M Krishna; Swaminathan, Akila; Siamwala, Jamila H; Sinha, Swaraj; Veeriah, Vimal; Sonar, Punam; Jadhav, Vivek; Jaffar Ali, B M; Chatterjee, Suvro

    2013-05-01

    Cadmium targets the vascular endothelium causing endothelial dysfunction and leakiness of endothelial barrier. Nitric oxide plays a major role in mediating endothelial functions including angiogenesis, migration and permeability. The present study investigates the nitric oxide effects on cadmium induced endothelial leakiness. Results of ex vivo and in vitro permeability assays showed that even a sub-lethal dose of cadmium chloride (1 µM) was sufficient to induce leakiness of endothelial cells. Cadmium drastically altered the actin polymerisation pattern and membrane tension of these cells compared to controls. Addition of nitric oxide donor Spermine NONOate (SP) significantly blunted cadmium-mediated effects and recover endothelial cells integrity. Cadmium-induced cytoskeletal rearrangements and membrane leakiness are associated with the low nitric oxide availability and high reactive oxygen species generation. In brief, we show the protective role of nitric oxide against cadmium-mediated endothelial leakiness. © 2013 International Federation for Cell Biology.

  12. A possible mechanism in DHEA-mediated protection against osteoarthritis.

    PubMed

    Li, Wei-Jun; Tang, Lu-Ping; Xiong, Yan; Chen, Wei-Ping; Zhou, Xin-Die; Ding, Qian-Hai; Wu, Li-Dong

    2014-11-01

    Dehydroepiandrosterone (DHEA) and its ester form, DHEA-S, are the most abundant steroids in human plasma. Our previous studies showed that DHEA protects against osteoarthritis (OA). The aim of this paper was to explore the possible mechanisms that underlie DHEA-mediated protection against OA. We tested the expression of β-catenin, it was increased significantly in OA. Rabbit cartilage was treated with various concentrations of DHEA in both IL-1β-induced rabbit chondrocytes and in rabbit cartilage from the anterior cruciate ligament transaction-induced OA model. We found DHEA decreased the expression of β-catenin. Then we further activated Wnt/β-catenin signaling by β-catenin transfection and inactivated it by the inhibitor Dickkopf1 in chondrocytes to reveal its role in the pathogenesis of OA. It turns out the protective effect of DHEA was significantly decreased when Wnt/β-catenin signaling was activated, while inactivating Wnt/β-catenin signaling enhanced the effects of DHEA. Therefore, we hypothesize that DHEA probably exerted its chondroprotective effect by regulating Wnt/β-catenin signaling. Our findings demonstrate the critical role of Wnt/β-catenin signaling in DHEA-mediated protection against OA. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. ABC-F Proteins Mediate Antibiotic Resistance through Ribosomal Protection.

    PubMed

    Sharkey, Liam K R; Edwards, Thomas A; O'Neill, Alex J

    2016-03-22

    Members of the ABC-F subfamily of ATP-binding cassette proteins mediate resistance to a broad array of clinically important antibiotic classes that target the ribosome of Gram-positive pathogens. The mechanism by which these proteins act has been a subject of long-standing controversy, with two competing hypotheses each having gained considerable support: antibiotic efflux versus ribosomal protection. Here, we report on studies employing a combination of bacteriological and biochemical techniques to unravel the mechanism of resistance of these proteins, and provide several lines of evidence that together offer clear support to the ribosomal protection hypothesis. Of particular note, we show that addition of purified ABC-F proteins to anin vitrotranslation assay prompts dose-dependent rescue of translation, and demonstrate that such proteins are capable of displacing antibiotic from the ribosomein vitro To our knowledge, these experiments constitute the first direct evidence that ABC-F proteins mediate antibiotic resistance through ribosomal protection.IMPORTANCEAntimicrobial resistance ranks among the greatest threats currently facing human health. Elucidation of the mechanisms by which microorganisms resist the effect of antibiotics is central to understanding the biology of this phenomenon and has the potential to inform the development of new drugs capable of blocking or circumventing resistance. Members of the ABC-F family, which includelsa(A),msr(A),optr(A), andvga(A), collectively yield resistance to a broader range of clinically significant antibiotic classes than any other family of resistance determinants, although their mechanism of action has been controversial since their discovery 25 years ago. Here we present the first direct evidence that proteins of the ABC-F family act to protect the bacterial ribosome from antibiotic-mediated inhibition. Copyright © 2016 Sharkey et al.

  14. 30 CFR 75.601-3 - Short circuit protection; dual element fuses; current ratings; maximum values.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Short circuit protection; dual element fuses... Trailing Cables § 75.601-3 Short circuit protection; dual element fuses; current ratings; maximum values. Dual element fuses having adequate current-interrupting capacity shall meet the requirements for short...

  15. 30 CFR 75.601-3 - Short circuit protection; dual element fuses; current ratings; maximum values.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Short circuit protection; dual element fuses... Trailing Cables § 75.601-3 Short circuit protection; dual element fuses; current ratings; maximum values. Dual element fuses having adequate current-interrupting capacity shall meet the requirements for short...

  16. 30 CFR 75.601-3 - Short circuit protection; dual element fuses; current ratings; maximum values.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Short circuit protection; dual element fuses... Trailing Cables § 75.601-3 Short circuit protection; dual element fuses; current ratings; maximum values. Dual element fuses having adequate current-interrupting capacity shall meet the requirements for...

  17. ABC-F Proteins Mediate Antibiotic Resistance through Ribosomal Protection

    PubMed Central

    Sharkey, Liam K. R.; Edwards, Thomas A.

    2016-01-01

    ABSTRACT Members of the ABC-F subfamily of ATP-binding cassette proteins mediate resistance to a broad array of clinically important antibiotic classes that target the ribosome of Gram-positive pathogens. The mechanism by which these proteins act has been a subject of long-standing controversy, with two competing hypotheses each having gained considerable support: antibiotic efflux versus ribosomal protection. Here, we report on studies employing a combination of bacteriological and biochemical techniques to unravel the mechanism of resistance of these proteins, and provide several lines of evidence that together offer clear support to the ribosomal protection hypothesis. Of particular note, we show that addition of purified ABC-F proteins to an in vitro translation assay prompts dose-dependent rescue of translation, and demonstrate that such proteins are capable of displacing antibiotic from the ribosome in vitro. To our knowledge, these experiments constitute the first direct evidence that ABC-F proteins mediate antibiotic resistance through ribosomal protection. PMID:27006457

  18. Protection from mitochondrial complex II inhibition in vitro and in vivo by Nrf2-mediated transcription.

    PubMed

    Calkins, Marcus J; Jakel, Rebekah J; Johnson, Delinda A; Chan, Kaimin; Kan, Yuet Wai; Johnson, Jeffrey A

    2005-01-04

    Complex II inhibitors 3-nitropropionic acid (3NP) and malonate cause striatal damage reminiscent of Huntington's disease and have been shown to involve oxidative stress in their pathogenesis. Because nuclear factor erythroid 2-related factor 2 (Nrf2)-dependent transcriptional activation by means of the antioxidant response element is known to coordinate the up-regulation of cytoprotective genes involved in combating oxidative stress, we investigated the significance of Nrf2 in complex II-induced toxicity. We found that Nrf2-deficient cells and Nrf2 knockout mice are significantly more vulnerable to malonate and 3NP and demonstrate increased antioxidant response element (ARE)-regulated transcription mediated by astrocytes. Furthermore, ARE preactivation by means of intrastriatal transplantation of Nrf2-overexpressing astrocytes before lesioning conferred dramatic protection against complex II inhibition. These observations implicate Nrf2 as an essential inducible factor in the protection against complex II inhibitor-mediated neurotoxicity. These data also introduce Nrf2-mediated ARE transcription as a potential target of preventative therapy in neurodegenerative disorders such as Huntington's disease.

  19. Refractory coating protects intricate graphite elements from high-temperature hydrogen

    NASA Technical Reports Server (NTRS)

    Ferris, J. R.; Patterson, R. L.; Steffen, R. J.; Vogel, C. E.

    1966-01-01

    Refractory coating protects graphite heater elements operating at high temperature in a hydrogen atmosphere. The coating is formed by painting the graphite elements with a composition containing powdered tungsten, and heat-treating it.

  20. Specific and nonspecific mediation of protective immunity to Toxoplasma gondii.

    PubMed Central

    Reyes, L; Frenkel, J K

    1987-01-01

    We studied the specificity of protection conferred by Toxoplasma gondii immune lymphocytes and their supernatants on infected hamster kidney cells, using Besnoitia jellisoni immune lymphocytes as a nonspecific control. The intracellular growth of the organisms was measured by [3H]uracil incorporation, and inhibition of multiplication was used as a measurement of immunity. Although the immune lymphocytes restricted principally the multiplication of homologous organisms, partial protection, expressed against the heterologous organism, was found. This was true for either parasite with intact lymphocytes or their supernatants. Exposure of immune lymphocytes to antigen for 18 to 24 h and treatment of kidney cells with supernatant fluids for 18 to 24 h were required for maximal protection. The specific protective mediator in supernatants of immune lymphocytes was characterized by dialysis as having a molecular weight between 3,000 and 12,000 and was found in the 3,000 to 5,000 peak after Sephadex G-50 chromatography. Nonspecific protective activity was greater than 12,000 by dialysis; it chromatographed in the excluded peak, measuring over 43,000, and was destroyed by exposure to pH 2. In vitro production of lymphokines from toxoplasma immune lymphocytes was first detected 7 to 10 days after vaccination of hamsters. At about the same time, hamsters began to resist challenge infection with the pathogenic RH strain of T. gondii and were able to prevent its multiplication in lungs, liver, spleen, and the subcutaneous infection site. The expression of tissue immunity and the production of toxoplasma-immune lymphokines appear to be time-related events. PMID:3557619

  1. Comments: Using Design Elements for Increasing the Severity of Causal Mediation Tests

    ERIC Educational Resources Information Center

    Steiner, Peter M.

    2012-01-01

    In this commentary, the author focuses on the use of design elements for increasing the severity of causal mediation tests. The estimation of causal mediation effects from observational data rests on rather stringent assumptions. In introducing and exemplifying ratio-of-mediator-probability weighting (RMPW), Hong and Nomi (henceforth HN) make…

  2. Comments: Using Design Elements for Increasing the Severity of Causal Mediation Tests

    ERIC Educational Resources Information Center

    Steiner, Peter M.

    2012-01-01

    In this commentary, the author focuses on the use of design elements for increasing the severity of causal mediation tests. The estimation of causal mediation effects from observational data rests on rather stringent assumptions. In introducing and exemplifying ratio-of-mediator-probability weighting (RMPW), Hong and Nomi (henceforth HN) make…

  3. The protective effects of trace elements against side effects induced by ionizing radiation

    PubMed Central

    2015-01-01

    Trace elements play crucial role in the maintenance of genome stability in the cells. Many endogenous defense enzymes are containing trace elements such as superoxide dismutase and metalloproteins. These enzymes are contributing in the detoxification of reactive oxidative species (ROS) induced by ionizing radiation in the cells. Zinc, copper, manganese, and selenium are main trace elements that have protective roles against radiation-induced DNA damages. Trace elements in the free salt forms have protective effect against cell toxicity induced by oxidative stress, metal-complex are more active in the attenuation of ROS particularly through superoxide dismutase mimetic activity. Manganese-complexes in protection of normal cell against radiation without any protective effect on cancer cells are more interesting compounds in this topic. The aim of this paper to review the role of trace elements in protection cells against genotoxicity and side effects induced by ionizing radiation. PMID:26157675

  4. Frequency Modulated Translocational Oscillations of Nrf2 Mediate the Antioxidant Response Element Cytoprotective Transcriptional Response

    PubMed Central

    Xue, Mingzhan; Momiji, Hiroshi; Rabbani, Naila; Barker, Guy; Bretschneider, Till; Shmygol, Anatoly; Rand, David A.

    2015-01-01

    Abstract Aims: Stress responsive signaling coordinated by nuclear factor erythroid 2-related factor 2 (Nrf2) provides an adaptive response for protection of cells against toxic insults, oxidative stress and metabolic dysfunction. Nrf2 regulates a battery of protective genes by binding to regulatory antioxidant response elements (AREs). The aim of this study was to examine how Nrf2 signals cell stress status and regulates transcription to maintain homeostasis. Results: In live cell microscopy we observed that Nrf2 undergoes autonomous translocational frequency-modulated oscillations between cytoplasm and nucleus. Oscillations occurred in quiescence and when cells were stimulated at physiological levels of activators, they decrease in period and amplitude and then evoke a cytoprotective transcriptional response. We propose a mechanism whereby oscillations are produced by negative feedback involving successive de-phosphorylation and phosphorylation steps. Nrf2 was inactivated in the nucleus and reactivated on return to the cytoplasm. Increased frequency of Nrf2 on return to the cytoplasm with increased reactivation or refresh-rate under stress conditions activated the transcriptional response mediating cytoprotective effects. The serine/threonine-protein phosphatase PGAM5, member of the Nrf2 interactome, was a key regulatory component. Innovation: We found that Nrf2 is activated in cells without change in total cellular Nrf2 protein concentration. Regulation of ARE-linked protective gene transcription occurs rather through translocational oscillations of Nrf2. We discovered cytoplasmic refresh rate of Nrf2 is important in maintaining and regulating the transcriptional response and links stress challenge to increased cytoplasmic surveillance. We found silencing and inhibition of PGAM5 provides potent activation of Nrf2. Conclusion: Frequency modulated translocational oscillations of Nrf2 mediate the ARE-linked cytoprotective transcriptional response. Antioxid. Redox

  5. CXCR5+ T helper cells mediate protective immunity against tuberculosis

    PubMed Central

    Slight, Samantha R.; Rangel-Moreno, Javier; Gopal, Radha; Lin, Yinyao; Fallert Junecko, Beth A.; Mehra, Smriti; Selman, Moises; Becerril-Villanueva, Enrique; Baquera-Heredia, Javier; Pavon, Lenin; Kaushal, Deepak; Reinhart, Todd A.; Randall, Troy D.; Khader, Shabaana A.

    2013-01-01

    One third of the world’s population is infected with Mycobacterium tuberculosis (Mtb). Although most infected people remain asymptomatic, they have a 10% lifetime risk of developing active tuberculosis (TB). Thus, the current challenge is to identify immune parameters that distinguish individuals with latent TB from those with active TB. Using human and experimental models of Mtb infection, we demonstrated that organized ectopic lymphoid structures containing CXCR5+ T cells were present in Mtb-infected lungs. In addition, we found that in experimental Mtb infection models, the presence of CXCR5+ T cells within ectopic lymphoid structures was associated with immune control. Furthermore, in a mouse model of Mtb infection, we showed that activated CD4+CXCR5+ T cells accumulated in Mtb-infected lungs and produced proinflammatory cytokines. Mice deficient in Cxcr5 had increased susceptibility to TB due to defective T cell localization within the lung parenchyma. We demonstrated that CXCR5 expression in T cells mediated correct T cell localization within TB granulomas, promoted efficient macrophage activation, protected against Mtb infection, and facilitated lymphoid follicle formation. These data demonstrate that CD4+CXCR5+ T cells play a protective role in the immune response against TB and highlight their potential use for future TB vaccine design and therapy. PMID:23281399

  6. Mast Cell Proteases as Protective and Inflammatory Mediators

    PubMed Central

    Caughey, George H.

    2014-01-01

    Proteases are the most abundant class of proteins produced by mast cells. Many of these are stored in membrane-enclosed intracellular granules until liberated by degranulating stimuli, which include cross-linking of high affinity IgE receptor FcεRI by IgE bound to multivalent allergen. Understanding and separating the functions of the proteases is important because expression differs among mast cells in different tissue locations. Differences between laboratory animals and humans in protease expression also influence the degree of confidence with which results obtained in animal models of mast cell function can be extrapolated to humans. The inflammatory potential of mast cell proteases was the first aspect of their biology to be explored and has received the most attention, in part because some of them—notably tryptases and chymases—are biomarkers of local and systemic mast cell degranulation and anaphylaxis. Although some of the proteases indeed augment allergic inflammation and are potential targets for inhibition to treat asthma and related allergic disorders, they are protective and even anti-inflammatory in some settings. For example, mast cell tryptases may protect from serious bacterial lung infections and may limit the “rubor” component of inflammation caused by vasodilating neuropeptides in the skin. Chymases help to maintain intestinal barrier function and to expel parasitic worms, and may support blood pressure during anaphylaxis by generating angiotensin II. In other life-or-death examples, carboxypeptidase A3 and other mast cell peptidases limit systemic toxicity of endogenous peptides like endothelin and neurotensin during septic peritonitis, and inactivate venom-associated peptides. On the other hand, mast cell peptidase-mediated destruction of protective cytokines, like IL-6, can enhance mortality from sepsis. Peptidases released from mast cells also influence non-mast cell proteases, such as by activating matrix metalloproteinase cascades

  7. L-carnitine protects against carboplatin-mediated renal injury: AMPK- and PPARα-dependent inactivation of NFAT3.

    PubMed

    Sue, Yuh-Mou; Chou, Hsiu-Chu; Chang, Chih-Cheng; Yang, Nian-Jie; Chou, Ying; Juan, Shu-Hui

    2014-01-01

    We have previously shown that carboplatin induces inflammation and apoptosis in renal tubular cells (RTCs) through the activation of the nuclear factor of activated T cells-3 (NFAT3) protein by reactive oxygen species (ROS), and that the ROS-mediated activation of NFAT3 is prevented by N-acetyl cysteine and heme oxygenase-1 treatment. In the current study, we investigated the underlying molecular mechanisms of the protective effect of L-carnitine on carboplatin-mediated renal injury. Balb/c mice and RTCs were used as model systems. Carboplatin-induced apoptosis in RTCs was examined using terminal-deoxynucleotidyl-transferase-mediated dUTP nick end labeling. We evaluated the effects of the overexpression of the peroxisome-proliferator-activated receptor alpha (PPARα) protein, the knockdown of PPARα gene, and the blockade of AMPK activation and PPARα to investigate the underlying mechanisms of the protective effect of L-carnitine on carboplatin-mediated renal injury. Carboplatin reduced the nuclear translocation, phosphorylation, and peroxisome proliferator responsive element transactivational activity of PPARα. These carboplatin-mediated effects were prevented by L-carnitine through a mechanism dependent on AMPK phosphorylation and subsequent PPARα activation. The activation of PPARα induced cyclooxygenase 2 (COX-2) and prostacyclin (PGI2) synthase expression that formed a positive feedback loop to further activate PPARα. The coimmunoprecipitation of the nuclear factor (NF) κB proteins increased following the induction of PPARα by L-carnitine, which reduced NFκB transactivational activity and cytokine expression. The in vivo study showed that the inactivation of AMPK suppressed the protective effect of L-carnitine in carboplatin-treated mice, indicating that AMPK phosphorylation is required for PPARα activation in the L-carnitine-mediated protection of RTC apoptosis caused by carboplatin. The results of our study provide molecular evidence that L

  8. DEMONSTRATION OF THE ANALYTIC ELEMENT METHOD FOR WELLHEAD PROTECTION

    EPA Science Inventory

    A new computer program has been developed to determine time-of-travel capture zones in relatively simple geohydrological settings. The WhAEM package contains an analytic element model that uses superposition of (many) closed form analytical solutions to generate a ground-water fl...

  9. DEMONSTRATION OF THE ANALYTIC ELEMENT METHOD FOR WELLHEAD PROTECTION

    EPA Science Inventory

    A new computer program has been developed to determine time-of-travel capture zones in relatively simple geohydrological settings. The WhAEM package contains an analytic element model that uses superposition of (many) closed form analytical solutions to generate a ground-water fl...

  10. Braving the Elements: Protecting Schools against Weather-Related Disasters.

    ERIC Educational Resources Information Center

    Breighner, Mary

    1997-01-01

    Discusses common weather-related hazards (floods, windstorms, and winter storms) and provides some steps administrators can take to protect their schools. Suggests administrators periodically assess their school's commitment to loss control, housekeeping, suitable building construction and reinforcement, sprinkler systems, water supply,…

  11. Braving the Elements: Protecting Schools against Weather-Related Disasters.

    ERIC Educational Resources Information Center

    Breighner, Mary

    1997-01-01

    Discusses common weather-related hazards (floods, windstorms, and winter storms) and provides some steps administrators can take to protect their schools. Suggests administrators periodically assess their school's commitment to loss control, housekeeping, suitable building construction and reinforcement, sprinkler systems, water supply,…

  12. Protective matching polymer powder coating of piezoelectric element

    NASA Astrophysics Data System (ADS)

    Gavrilova, V. A.; Fazlyyyakhmatov, M. G.; Kashapov, N. F.

    2013-12-01

    Objects of research are coatings and technology of their applying to the piezoelectric elements for ultrasound. Acoustic impedance and thicknesses of matching layers for medical ultrasound transducers have been defined. In this paper performance characteristics of coating systems with predetermined properties have been selected. The conditions for selection of polymer powder paint for quarter wave matching layer have been determined. Conditions of forming polymer powder coatings have been proposed.

  13. Finite Element Modeling and Exploration of Double Hearing Protection Systems

    DTIC Science & Technology

    2006-02-10

    broad frequency range were determined from this method. The elastomeric rubber material was cut into small wafers of 2 to 5mm thickness. A mass was... material (being 0.1 for soft elastomeric foams), G and E are the shear and elastic moduli of the material , respectively, D is the diameter of the...and to investigate the behavior of the modeled system. The foam earplug material properties for the finite element model are required in the same shear

  14. Mathematical simulation of hydrocarbon fuel conversion in heat-protection elements of hypersonic aircrafts

    NASA Astrophysics Data System (ADS)

    Kuranov, A. L.; Korabel'nikov, A. V.; Mikhailov, A. M.

    2017-01-01

    We consider a mathematical model of hydrocarbon fuel conversion in a thermochemical reactor as an element of heat protection of a hypersonic aircraft. The application of this model has made it possible to enrich information obtained in experimental studies.

  15. Early eradication of persistent Salmonella infection primes antibody-mediated protective immunity to recurrent infection.

    PubMed

    Johanns, Tanner M; Law, Calvin Y; Kalekar, Lokeshchandra A; O'Donnell, Hope; Ertelt, James M; Rowe, Jared H; Way, Sing Sing

    2011-04-01

    Typhoid fever is a systemic, persistent infection caused by host-specific strains of Salmonella. Although the use of antibiotics has reduced the complications associated with primary infection, recurrent infection remains an important cause of ongoing human morbidity and mortality. Herein, we investigated the impacts of antibiotic eradication of primary infection on protection against secondary recurrent infection. Using a murine model of persistent Salmonella infection, we demonstrate protection against recurrent infection is sustained despite early eradication of primary infection. In this model, protection is not mediated by CD4(+) or CD8(+) T cells because depletion of these cells either alone or in combination prior to rechallenge does not abrogate protection. Instead, infection followed by antibiotic-mediated clearance primes robust levels of Salmonella-specific antibody that can adoptively transfer protection to naïve mice. Thus, eradication of persistent Salmonella infection primes antibody-mediated protective immunity to recurrent infection.

  16. MICROBIALLY MEDIATED LEACHING OF RARE EARTH ELEMENTS FROM RECYCLABLE MATERIALS

    SciTech Connect

    Reed, D. W.; Fujita, Y.; Daubaras, D. L.; Bruhn, D. F.; Reiss, J. H.; Thompson, V. S.; Jiao, Y.

    2016-09-01

    Bioleaching offers a potential approach for recovery of rare earth elements (REE) from recyclable materials, such as fluorescent lamp phosphors or degraded industrial catalysts. Microorganisms were enriched from REE-containing ores and recyclable materials with the goal of identifying strains capable of extracting REE from solid materials. Over 100 heterotrophic microorganisms were isolated and screened for their ability to produce organic acids capable of leaching REE. The ten most promising isolates were most closely related to Pseudomonas, Acinetobacter and Talaromyces. Of the acids produced, gluconic acid appeared to be the most effective at leaching REE (yttrium, lanthanum, cerium, europium, and terbium) from retorted phosphor powders (RPP), fluidized cracking catalyst (FCC), and europium-doped yttrium oxide (YOEu). We found that an Acinetobacter isolates, BH1, was the most capable strain and able to leach 33% of the total REE content from the FCC material. These results support the continuing evaluation of gluconic acid-producing microbes for large-scale REE recovery from recyclable materials.

  17. Exercise mediated protection of diabetic heart through modulation of microRNA mediated molecular pathways.

    PubMed

    Lew, Jason Kar Sheng; Pearson, James T; Schwenke, Daryl O; Katare, Rajesh

    2017-01-13

    Hyperglycaemia, hypertension, dyslipidemia and insulin resistance collectively impact on the myocardium of people with diabetes, triggering molecular, structural and myocardial abnormalities. These have been suggested to aggravate oxidative stress, systemic inflammation, myocardial lipotoxicity and impaired myocardial substrate utilization. As a consequence, this leads to the development of a spectrum of cardiovascular diseases, which may include but not limited to coronary endothelial dysfunction, and left ventricular remodelling and dysfunction. Diabetic heart disease (DHD) is the term used to describe the presence of heart disease specifically in diabetic patients. Despite significant advances in medical research and long clinical history of anti-diabetic medications, the risk of heart failure in people with diabetes never declines. Interestingly, sustainable and long-term exercise regimen has emerged as an effective synergistic therapy to combat the cardiovascular complications in people with diabetes, although the precise molecular mechanism(s) underlying this protection remain unclear. This review provides an overview of the underlying mechanisms of hyperglycaemia- and insulin resistance-mediated DHD with a detailed discussion on the role of different intensities of exercise in mitigating these molecular alterations in diabetic heart. In particular, we provide the possible role of exercise on microRNAs, the key molecular regulators of several pathophysiological processes.

  18. Insulin Regulation of the Glucagon Gene is Mediated by an Insulin- Responsive DNA Element

    NASA Astrophysics Data System (ADS)

    Philippe, Jacques

    1991-08-01

    Diabetes mellitus is characterized by insulin deficiency and high plasma glucagon levels, which can be normalized by insulin replacement. It has previously been reported that glucagon gene expression is negatively regulated by insulin at the transcriptional level. By transfection studies, I have now localized a DNA control element that mediates insulin effects on glucagon gene transcription. This element also confers insulin responsiveness to a heterologous promoter. DNA-binding proteins that specifically interact with this insulin-responsive element are found in both glucagon- and non-glucagon-producing cells; and the pattern of binding, as assessed by the gel retardation assay, is not modified by prior insulin treatment.

  19. Modeling the ecology of symbiont-mediated protection against parasites.

    PubMed

    Kwiatkowski, Marek; Vorburger, Christoph

    2012-05-01

    There is increasing evidence that many maternally transmitted symbionts protect their hosts against parasites, thus ensuring their own persistence. Despite the protection they provide, such symbionts are typically found in only a fraction of the host population. This suggests that symbiont-conferred resistance is costly or that the maternal inheritance of symbionts is not perfect. To investigate these hypotheses and other properties of this complex ecological system, we develop a mathematical model based on the example of bacterial endosymbionts that protect aphids against parasitoid wasps. Simulations show that in the absence of more complex effects, a very fine balance between the costs of harboring symbionts and the strength of protection they provide is required to maintain coexistence of protected and unprotected hosts. These constraints are significantly relaxed and coexistence becomes a common outcome if deployment of symbiont-provided defenses upon a parasite attack entails an additional (induced) cost. Transmission rates of symbionts also affect coexistence, which is more frequently observed under high (but not perfect) fidelity of vertical transfer and low rates of horizontal transfer. Finally, we show that the prevalence of defensive symbionts has a strong influence on the population dynamics of hosts and parasites: population sizes are stable if and only if protected hosts dominate.

  20. The plant-unique cis-element that mediates signaling from multiple endoplasmic reticulum stress sensors

    PubMed Central

    Hayashi, Shimpei; Takaiwa, Fumio

    2013-01-01

    The accumulation of unfolded proteins in the ER lumen induces intracellular signaling mediated by the ER stress sensor protein IRE1. Our recent study identified a new common cis-element of ER stress-responsive genes (such as rice BiP paralogs and WRKY45) that were regulated via an IRE1-dependent pathway. ER stress-responsive cis-elements had been expected to be conserved between plants and mammals. However, contrary to expectations, sequences of the plant cis-element, pUPRE-II, were not identical to those of its mammalian counterpart. Additionally, pUPRE-II also interacted with another ER stress sensor protein and mediated multiple signaling pathways. Here, we provide a summary of the results that suggest the complicated mechanism underlying the regulation of ER stress-responsive gene expression in plants. PMID:23518586

  1. The plant-unique cis-element that mediates signaling from multiple endoplasmic reticulum stress sensors.

    PubMed

    Hayashi, Shimpei; Takaiwa, Fumio

    2013-06-01

    The accumulation of unfolded proteins in the ER lumen induces intracellular signaling mediated by the ER stress sensor protein IRE1. Our recent study identified a new common cis-element of ER stress-responsive genes (such as rice BiP paralogs and WRKY45) that were regulated via an IRE1-dependent pathway. ER stress-responsive cis-elements had been expected to be conserved between plants and mammals. However, contrary to expectations, sequences of the plant cis-element, pUPRE-II, were not identical to those of its mammalian counterpart. Additionally, pUPRE-II also interacted with another ER stress sensor protein and mediated multiple signaling pathways. Here, we provide a summary of the results that suggest the complicated mechanism underlying the regulation of ER stress-responsive gene expression in plants.

  2. Protective effect of Pterostilbene against free radical mediated oxidative damage

    PubMed Central

    2013-01-01

    Background Pterostilbene, a methoxylated analog of Resveratrol, is gradually gaining more importance as a therapeutic drug owing to its higher lipophilicity, bioavailability and biological activity than Resveratrol. This study was undertaken to characterize its ability to scavenge free radicals such as superoxide, hydroxyl and hydrogen peroxide and to protect bio-molecules within a cell against oxidative insult. Methods Anti-oxidant activity of Pterostilbene was evaluated extensively by employing several in vitro radical scavenging/inhibiting assays and pulse radiolysis study. In addition, its ability to protect rat liver mitochondria against tertiary-butyl hydroperoxide (TBHP) and hydroxyl radical generated oxidative damage was determined by measuring the damage markers such as protein carbonyls, protein sulphydryls, lipid hydroperoxides, lipid peroxides and 8-hydroxy-2'-deoxyguanosine. Pterostilbene was also evaluated for its ability to inhibit •OH radical induced single strand breaks in pBR322 DNA. Result Pterostilbene exhibited strong anti-oxidant activity against various free radicals such as DPPH, ABTS, hydroxyl, superoxide and hydrogen peroxide in a concentration dependent manner. Pterostilbene conferred protection to proteins, lipids and DNA in isolated mitochondrial fractions against TBHP and hydroxyl radical induced oxidative damage. It also protected pBR322 DNA against oxidative assault. Conclusions Thus, present study provides an evidence for the strong anti-oxidant property of Pterostilbene, methoxylated analog of Resveratrol, thereby potentiating its role as an anti-oxidant. PMID:24070177

  3. The DAL7 promoter consists of multiple elements that cooperatively mediate regulation of the gene's expression.

    PubMed Central

    Yoo, H S; Cooper, T G

    1989-01-01

    Expression of the allantoin system genes in Saccharomyces cerevisiae is induced by allophanate or its analog, oxalurate. This work provides evidence for the involvement of distinct types of cis-acting elements in the induction process. The first element was found to have the properties of an upstream activation sequence (UAS). This element was localized to a 16-base-pair (bp) DNA fragment containing a short 5-bp sequence that occurred repeatedly in the upstream region of DAL7. When present in two or more copies, the 16-bp fragment supported high-level beta-galactosidase production in a CYC1-lacZ expression vector; there was, however, no response to the allantoin pathway inducer. The second element had the properties of a negatively acting element or upstream repression sequence (URS). This element was localized to a 16-bp DNA fragment containing an 8-bp sequence that was repeated four times in the upstream region of DAL7. A fragment containing the 8-bp repeated sequence placed adjacent to the UAS-containing fragment mediated inhibition of the ability of the UAS to support lacZ expression regardless of whether inducer was present. A third element, designated an upstream induction sequence (UIS), was required for response to inducer. The UIS was localized to a small DNA fragment containing an approximately 10-bp sequence that was repeated twice in the upstream region of DAL7. When a fragment containing the 10-bp repeated sequence was placed adjacent to these UAS and URS elements, the construction (UIS-UAS-URS) supported normal oxalurate-mediated induction of beta-galactosidase synthesis. These data are consistent with the suggestion that multiple, cis-acting elements participate in the induction process. Images PMID:2552287

  4. Protective pathways against colitis mediated by appendicitis and appendectomy

    PubMed Central

    Cheluvappa, R; Luo, A S; Palmer, C; Grimm, M C

    2011-01-01

    Appendicitis followed by appendectomy (AA) at a young age protects against inflammatory bowel disease (IBD). Using a novel murine appendicitis model, we showed that AA protected against subsequent experimental colitis. To delineate genes/pathways involved in this protection, AA was performed and samples harvested from the most distal colon. RNA was extracted from four individual colonic samples per group (AA group and double-laparotomy control group) and each sample microarray analysed followed by gene-set enrichment analysis (GSEA). The gene-expression study was validated by quantitative reverse transcription–polymerase chain reaction (RT–PCR) of 14 selected genes across the immunological spectrum. Distal colonic expression of 266 gene-sets was up-regulated significantly in AA group samples (false discovery rates < 1%; P-value < 0·001). Time–course RT–PCR experiments involving the 14 genes displayed down-regulation over 28 days. The IBD-associated genes tnfsf10, SLC22A5, C3, ccr5, irgm, ptger4 and ccl20 were modulated in AA mice 3 days after surgery. Many key immunological and cellular function-associated gene-sets involved in the protective effect of AA in experimental colitis were identified. The down-regulation of 14 selected genes over 28 days after surgery indicates activation, repression or de-repression of these genes leading to downstream AA-conferred anti-colitis protection. Further analysis of these genes, profiles and biological pathways may assist in developing better therapeutic strategies in the management of intractable IBD. PMID:21707591

  5. Vaccination against endogenous retrotransposable element consensus sequences does not protect rhesus macaques from SIVsmE660 infection and replication.

    PubMed

    Sheppard, Neil C; Jones, R Brad; Burwitz, Benjamin J; Nimityongskul, Francesca A; Newman, Laura P; Buechler, Matthew B; Reed, Jason S; Piaskowski, Shari M; Weisgrau, Kim L; Castrovinci, Philip A; Wilson, Nancy A; Ostrowski, Mario A; Park, Byung; Nixon, Douglas F; Rakasz, Eva G; Sacha, Jonah B

    2014-01-01

    The enormous sequence diversity of HIV remains a major roadblock to the development of a prophylactic vaccine and new approaches to induce protective immunity are needed. Endogenous retrotransposable elements (ERE) such as endogenous retrovirus K (ERV)-K and long interspersed nuclear element-1 (LINE-1) are activated during HIV-1-infection and could represent stable, surrogate targets to eliminate HIV-1-infected cells. Here, we explored the hypothesis that vaccination against ERE would protect macaques from acquisition and replication of simian immunodeficiency virus (SIV). Following vaccination with antigens derived from LINE-1 and ERV-K consensus sequences, animals mounted immune responses that failed to delay acquisition of SIVsmE660. We observed no differences in acute or set point viral loads between ERE-vaccinated and control animals suggesting that ERE-specific responses were not protective. Indeed, ERE-specific T cells failed to expand anamnestically in vivo following infection with SIVsmE660 and did not recognize SIV-infected targets in vitro, in agreement with no significant induction of targeted ERE mRNA by SIV in macaque CD4+ T cells. Instead, lower infection rates and viral loads correlated significantly to protective TRIM5α alleles. Cumulatively, these data demonstrate that vaccination against the selected ERE consensus sequences in macaques did not lead to immune-mediated recognition and killing of SIV-infected cells, as has been shown for HIV-infected human cells using patient-derived HERV-K-specific T cells. Thus, further research is required to identify the specific nonhuman primate EREs and retroviruses that recapitulate the activity of HIV-1 in human cells. These results also highlight the complexity in translating observations of the interplay between HIV-1 and human EREs to animal models.

  6. Vaccination against Endogenous Retrotransposable Element Consensus Sequences Does Not Protect Rhesus Macaques from SIVsmE660 Infection and Replication

    PubMed Central

    Sheppard, Neil C.; Jones, R. Brad; Burwitz, Benjamin J.; Nimityongskul, Francesca A.; Newman, Laura P.; Buechler, Matthew B.; Reed, Jason S.; Piaskowski, Shari M.; Weisgrau, Kim L.; Castrovinci, Philip A.; Wilson, Nancy A.; Ostrowski, Mario A.; Park, Byung; Nixon, Douglas F.; Rakasz, Eva G.; Sacha, Jonah B.

    2014-01-01

    The enormous sequence diversity of HIV remains a major roadblock to the development of a prophylactic vaccine and new approaches to induce protective immunity are needed. Endogenous retrotransposable elements (ERE) such as endogenous retrovirus K (ERV)-K and long interspersed nuclear element-1 (LINE-1) are activated during HIV-1-infection and could represent stable, surrogate targets to eliminate HIV-1-infected cells. Here, we explored the hypothesis that vaccination against ERE would protect macaques from acquisition and replication of simian immunodeficiency virus (SIV). Following vaccination with antigens derived from LINE-1 and ERV-K consensus sequences, animals mounted immune responses that failed to delay acquisition of SIVsmE660. We observed no differences in acute or set point viral loads between ERE-vaccinated and control animals suggesting that ERE-specific responses were not protective. Indeed, ERE-specific T cells failed to expand anamnestically in vivo following infection with SIVsmE660 and did not recognize SIV-infected targets in vitro, in agreement with no significant induction of targeted ERE mRNA by SIV in macaque CD4+ T cells. Instead, lower infection rates and viral loads correlated significantly to protective TRIM5α alleles. Cumulatively, these data demonstrate that vaccination against the selected ERE consensus sequences in macaques did not lead to immune-mediated recognition and killing of SIV-infected cells, as has been shown for HIV-infected human cells using patient-derived HERV-K-specific T cells. Thus, further research is required to identify the specific nonhuman primate EREs and retroviruses that recapitulate the activity of HIV-1 in human cells. These results also highlight the complexity in translating observations of the interplay between HIV-1 and human EREs to animal models. PMID:24651676

  7. Critical role of transcription factor cyclic AMP response element modulator in beta1-adrenoceptor-mediated cardiac dysfunction.

    PubMed

    Lewin, Geertje; Matus, Marek; Basu, Abhijit; Frebel, Karin; Rohsbach, Sebastian Pius; Safronenko, Andrej; Seidl, Matthias Dodo; Stümpel, Frank; Buchwalow, Igor; König, Simone; Engelhardt, Stefan; Lohse, Martin J; Schmitz, Wilhelm; Müller, Frank Ulrich

    2009-01-06

    Chronic stimulation of the beta(1)-adrenoceptor (beta(1)AR) plays a crucial role in the pathogenesis of heart failure; however, underlying mechanisms remain to be elucidated. The regulation by transcription factors cAMP response element-binding protein (CREB) and cyclic AMP response element modulator (CREM) represents a fundamental mechanism of cyclic AMP-dependent gene control possibly implicated in beta(1)AR-mediated cardiac deterioration. We studied the role of CREM in beta(1)AR-mediated cardiac effects, comparing transgenic mice with heart-directed expression of beta(1)AR in the absence and presence of functional CREM. CREM inactivation protected from cardiomyocyte hypertrophy, fibrosis, and left ventricular dysfunction in beta(1)AR-overexpressing mice. Transcriptome and proteome analysis revealed a set of predicted CREB/CREM target genes including the cardiac ryanodine receptor, tropomyosin 1alpha, and cardiac alpha-actin as altered on the mRNA or protein level along with the improved phenotype in CREM-deficient beta(1)AR-transgenic hearts. The results imply the regulation of genes by CREM as an important mechanism of beta(1)AR-induced cardiac damage in mice.

  8. The Role of Lipid Competition for Endosymbiont-Mediated Protection against Parasitoid Wasps in Drosophila

    PubMed Central

    Schüpfer, Fanny

    2016-01-01

    ABSTRACT Insects commonly harbor facultative bacterial endosymbionts, such as Wolbachia and Spiroplasma species, that are vertically transmitted from mothers to their offspring. These endosymbiontic bacteria increase their propagation by manipulating host reproduction or by protecting their hosts against natural enemies. While an increasing number of studies have reported endosymbiont-mediated protection, little is known about the mechanisms underlying this protection. Here, we analyze the mechanisms underlying protection from parasitoid wasps in Drosophila melanogaster mediated by its facultative endosymbiont Spiroplasma poulsonii. Our results indicate that S. poulsonii exerts protection against two distantly related wasp species, Leptopilina boulardi and Asobara tabida. S. poulsonii-mediated protection against parasitoid wasps takes place at the pupal stage and is not associated with an increased cellular immune response. In this work, we provide three important observations that support the notion that S. poulsonii bacteria and wasp larvae compete for host lipids and that this competition underlies symbiont-mediated protection. First, lipid quantification shows that both S. poulsonii and parasitoid wasps deplete D. melanogaster hemolymph lipids. Second, the depletion of hemolymphatic lipids using the Lpp RNA interference (Lpp RNAi) construct reduces wasp success in larvae that are not infected with S. poulsonii and blocks S. poulsonii growth. Third, we show that the growth of S. poulsonii bacteria is not affected by the presence of the wasps, indicating that when S. poulsonii is present, larval wasps will develop in a lipid-depleted environment. We propose that competition for host lipids may be relevant to endosymbiont-mediated protection in other systems and could explain the broad spectrum of protection provided. PMID:27406568

  9. Vaccine Mediated Protection Against Zika Virus-Induced Congenital Disease.

    PubMed

    Richner, Justin M; Jagger, Brett W; Shan, Chao; Fontes, Camila R; Dowd, Kimberly A; Cao, Bin; Himansu, Sunny; Caine, Elizabeth A; Nunes, Bruno T D; Medeiros, Daniele B A; Muruato, Antonio E; Foreman, Bryant M; Luo, Huanle; Wang, Tian; Barrett, Alan D; Weaver, Scott C; Vasconcelos, Pedro F C; Rossi, Shannan L; Ciaramella, Giuseppe; Mysorekar, Indira U; Pierson, Theodore C; Shi, Pei-Yong; Diamond, Michael S

    2017-07-13

    The emergence of Zika virus (ZIKV) and its association with congenital malformations has prompted the rapid development of vaccines. Although efficacy with multiple viral vaccine platforms has been established in animals, no study has addressed protection during pregnancy. We tested in mice two vaccine platforms, a lipid nanoparticle-encapsulated modified mRNA vaccine encoding ZIKV prM and E genes and a live-attenuated ZIKV strain encoding an NS1 protein without glycosylation, for their ability to protect against transmission to the fetus. Vaccinated dams challenged with a heterologous ZIKV strain at embryo day 6 (E6) and evaluated at E13 showed markedly diminished levels of viral RNA in maternal, placental, and fetal tissues, which resulted in protection against placental damage and fetal demise. As modified mRNA and live-attenuated vaccine platforms can restrict in utero transmission of ZIKV in mice, their further development in humans to prevent congenital ZIKV syndrome is warranted. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Somatostatin protects human retinal pericytes from inflammation mediated by microglia.

    PubMed

    Mazzeo, Aurora; Arroba, Ana I; Beltramo, Elena; Valverde, Angela M; Porta, Massimo

    2017-11-01

    Diabetic retinopathy (DR) is usually considered a microvascular disease. However, involvement of the neuroretina in the early stages of DR has recently gained major credit. Inflammatory processes, leading to glial activation and neuronal apoptosis, develop early in the retina of diabetic subjects. Pericytes constitute a link between the vascular and the neural retina, play a central role in blood-retinal barrier maintenance, and may influence neuroinflammation. Somatostatin (SST) is a potent neuroprotective factor, which is down-regulated during early DR. In this paper, we have investigated the effects of the inflammatory signals triggered by the activation of microglia on inflammation and apoptosis/survival pathways in pericytes. Microglia cells (Bv-2) were stimulated with lipopolysaccharide (LPS) and/or SST. Human retinal pericytes (HRP) were exposed to conditioned media (CM) collected from Bv-2 cells in physiological conditions and in the settings described above. A panel of inflammation, apoptosis and survival mediators was analyzed. HRP treated with LPS-CM showed a significant increase of pro-inflammatory (iNos and TNFα) and pro-apoptotic mediators (FasL, active caspase-8, tBid and Bax), and a concomitant decrease in pro-survival factors (BclxL and pAkt). SST added to LPS was able to counteract these effects in all conditions. In conclusion, SST is able to modulate apoptosis/survival pathways in HRP during microglia-mediated inflammation. These results demonstrate a crosstalk between microglia and retinal pericytes, evidencing a possible defensive role of microglia in the early phases of DR. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Microbial Herd Protection Mediated by Antagonistic Interaction in Polymicrobial Communities

    PubMed Central

    Wong, Megan J. Q.; Liang, Xiaoye; Smart, Matt; Tang, Le; Moore, Richard; Ingalls, Brian

    2016-01-01

    ABSTRACT In host and natural environments, microbes often exist in complex multispecies communities. The molecular mechanisms through which such communities develop and persist, despite significant antagonistic interactions between species, are not well understood. The type VI secretion system (T6SS) is a lethal weapon commonly employed by Gram-negative bacteria to inhibit neighboring species through the delivery of toxic effectors. It is well established that intraspecies protection is conferred by immunity proteins that neutralize effector toxicities. In contrast, the mechanisms for interspecies protection are not clear. Here we use two T6SS-active antagonistic bacterial species, Aeromonas hydrophila and Vibrio cholerae, to demonstrate that interspecies protection is dependent on effectors. A. hydrophila and V. cholerae do not share conserved immunity genes but could coexist equally in a mixture. However, mutants lacking the T6SS or effectors were effectively eliminated by the competing wild-type strain. Time-lapse microscopic analyses showed that mutually lethal interactions drive the segregation of mixed species into distinct single-species clusters by eliminating interspersed single cells. Cluster formation provides herd protection by abolishing lethal interactions inside each cluster and restricting the interactions to the boundary. Using an agent-based modeling approach, we simulated the antagonistic interactions of two hypothetical species. The resulting simulations recapitulated our experimental observations. These results provide mechanistic insights regarding the general role of microbial weapons in determining the structures of complex multispecies communities. IMPORTANCE Investigating the warfare of microbes allows us to better understand the ecological relationships in complex microbial communities such as the human microbiota. Here we use the T6SS, a deadly bacterial weapon, as a model to demonstrate the importance of lethal interactions in

  12. Tissue-Protective Effects of NKG2A in Immune-Mediated Clearance of Virus Infection

    PubMed Central

    DeBerge, Matthew P.; Ruby, Jessica A.; Liu, Jun; Schneider, Mark J.; Wang, Yan; Hahn, Young S.; Enelow, Richard I.

    2014-01-01

    Virus infection triggers a CD8+ T cell response that aids in virus clearance, but also expresses effector functions that may result in tissue injury. CD8+ T cells express a variety of activating and inhibiting ligands, though regulation of the expression of inhibitory receptors is not well understood. The ligand for the inhibitory receptor, NKG2A, is the non-classical MHC-I molecule Qa1b, which may also serve as a putative restricting element for the T cell receptors of purported regulatory CD8+ T cells. We have previously shown that Qa1b-null mice suffer considerably enhanced immunopathologic lung injury in the context of CD8+ T cell-mediated clearance of influenza infection, as well as evidence in a non-viral system that failure to ligate NKG2A on CD8+ effector T cells may represent an important component of this process. In this report, we examine the requirements for induction of NKG2A expression, and show that NKG2A expression by CD8+ T cells occurs as a result of migration from the MLN to the inflammatory lung environment, irrespective of peripheral antigen recognition. Further, we confirmed that NKG2A is a mediator in limiting immunopathology in virus infection using mice with a targeted deletion of NKG2A, and infecting the mutants with two different viruses, influenza and adenovirus. In neither infection is virus clearance altered. In influenza infection, the enhanced lung injury was associated with increased chemoattractant production, increased infiltration of inflammatory cells, and significantly enhanced alveolar hemorrhage. The primary mechanism of enhanced injury was the loss of negative regulation of CD8+ T cell effector function. A similar effect was observed in the livers of mutant mice infected intravenously with adenovirus. These results demonstrate the immunoregulatory role of CD8+ NKG2A expression in virus infection, which negatively regulates T cell effector functions and contributes to protection of tissue integrity during virus clearance

  13. Tissue-protective effects of NKG2A in immune-mediated clearance of virus infection.

    PubMed

    Ely, Kenneth H; Matsuoka, Mitsuo; DeBerge, Matthew P; Ruby, Jessica A; Liu, Jun; Schneider, Mark J; Wang, Yan; Hahn, Young S; Enelow, Richard I

    2014-01-01

    Virus infection triggers a CD8(+) T cell response that aids in virus clearance, but also expresses effector functions that may result in tissue injury. CD8(+) T cells express a variety of activating and inhibiting ligands, though regulation of the expression of inhibitory receptors is not well understood. The ligand for the inhibitory receptor, NKG2A, is the non-classical MHC-I molecule Qa1(b), which may also serve as a putative restricting element for the T cell receptors of purported regulatory CD8(+) T cells. We have previously shown that Qa1(b)-null mice suffer considerably enhanced immunopathologic lung injury in the context of CD8(+) T cell-mediated clearance of influenza infection, as well as evidence in a non-viral system that failure to ligate NKG2A on CD8(+) effector T cells may represent an important component of this process. In this report, we examine the requirements for induction of NKG2A expression, and show that NKG2A expression by CD8(+) T cells occurs as a result of migration from the MLN to the inflammatory lung environment, irrespective of peripheral antigen recognition. Further, we confirmed that NKG2A is a mediator in limiting immunopathology in virus infection using mice with a targeted deletion of NKG2A, and infecting the mutants with two different viruses, influenza and adenovirus. In neither infection is virus clearance altered. In influenza infection, the enhanced lung injury was associated with increased chemoattractant production, increased infiltration of inflammatory cells, and significantly enhanced alveolar hemorrhage. The primary mechanism of enhanced injury was the loss of negative regulation of CD8(+) T cell effector function. A similar effect was observed in the livers of mutant mice infected intravenously with adenovirus. These results demonstrate the immunoregulatory role of CD8(+) NKG2A expression in virus infection, which negatively regulates T cell effector functions and contributes to protection of tissue integrity during

  14. Social Differentiation of Sun-Protection Behaviors: The Mediating Role of Cognitive Factors.

    PubMed

    Bocquier, Aurélie; Fressard, Lisa; Legleye, Stéphane; Verger, Pierre; Peretti-Watel, Patrick

    2016-03-01

    Adherence to sun-protection guidelines in developed countries is low, especially among people of low SES. Mechanisms underlying this social differentiation are poorly understood. This study aimed to examine the social differentiation of sun-protection behaviors and of two cognitive factors (knowledge about both sun health and behavioral risk factors for cancer) and to determine if these cognitive factors mediate the association between SES and sun-protection behaviors. Data came from the 2010 Baromètre Cancer survey (analyzed in 2014), a random cross-sectional telephone survey conducted among the French general population (n=3,359 individuals aged 15-75 years). First, bivariate associations between a composite individual SES indicator (based on education level, occupation, and income) and both sun-protection behaviors and cognitive factors were tested with chi-square tests and ANOVA. Then, confirmatory factor analysis and structural equation modeling were used to test the mediating role of cognitive factors with a multiple mediation model including four latent variables. In bivariate analyses, the individual SES indicator was positively associated with sun-protection behaviors and both cognitive factors. Multiple mediation analyses showed that both cognitive factors partially mediated the effect of individual SES on sun-protection behaviors. The overall proportion of mediated effects was 48%. The direct effect of SES remained significant. These results suggest that interventions aimed at modifying the knowledge and perceptions of people of low SES might help to reduce social differentiation of sun-protection behaviors. Further qualitative research is needed to better understand these cognitive factors and develop suitable prevention messages. Copyright © 2016 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  15. Stress-Mediated cis-Element Transcription Factor Interactions Interconnecting Primary and Specialized Metabolism in planta

    PubMed Central

    Sheshadri, S. A.; Nishanth, M. J.; Simon, Bindu

    2016-01-01

    Plant specialized metabolites are being used worldwide as therapeutic agents against several diseases. Since the precursors for specialized metabolites come through primary metabolism, extensive investigations have been carried out to understand the detailed connection between primary and specialized metabolism at various levels. Stress regulates the expression of primary and specialized metabolism genes at the transcriptional level via transcription factors binding to specific cis-elements. The presence of varied cis-element signatures upstream to different stress-responsive genes and their transcription factor binding patterns provide a prospective molecular link among diverse metabolic pathways. The pattern of occurrence of these cis-elements (overrepresentation/common) decipher the mechanism of stress-responsive upregulation of downstream genes, simultaneously forming a molecular bridge between primary and specialized metabolisms. Though many studies have been conducted on the transcriptional regulation of stress-mediated primary or specialized metabolism genes, but not much data is available with regard to cis-element signatures and transcription factors that simultaneously modulate both pathway genes. Hence, our major focus would be to present a comprehensive analysis of the stress-mediated interconnection between primary and specialized metabolism genes via the interaction between different transcription factors and their corresponding cis-elements. In future, this study could be further utilized for the overexpression of the specific transcription factors that upregulate both primary and specialized metabolism, thereby simultaneously improving the yield and therapeutic content of plants. PMID:27933071

  16. Role of Fc-mediated antibody function in protective immunity against HIV-1.

    PubMed

    Lewis, George K

    2014-05-01

    The importance of Fc-mediated effector function in protective immunity to HIV-1 (hereafter referred to simply as HIV) is becoming increasingly apparent. A large of number of studies in natural infection cohorts, spanning the last 26 years, have associated Fc-mediated effector function, particularly antibody-dependent cellular cytotoxicity, with a favourable clinical course. These studies strongly suggest a role for Fc-mediated effector function in the post-infection control of viraemia. More recently, studies in both humans and non-human primates (NHPs) also implicate Fc-mediated effector function in blocking HIV acquisition. Accordingly, this review will discuss the results supporting a role of Fc-mediated effector function in both blocking acquisition and post-infection control of viraemia. Parallel studies in NHPs and humans will be compared for common themes. Context for this discussion will be provided by summarizing the temporal emergence of key host and virological events over the course of an untreated HIV infection framing where, when and how Fc-mediated effector function might be protective. A hypothesis that Fc-mediated effector function protects primarily in the early stages of both acquisition and post-infection control of viraemia will be developed.

  17. Resveratrol inhibits estrogen-induced breast carcinogenesis through induction of NRF2-mediated protective pathways

    PubMed Central

    Singh, Bhupendra; Shoulson, Rivka; Chatterjee, Anwesha; Ronghe, Amruta; Bhat, Nimee K.; Dim, Daniel C.; Bhat, Hari K.

    2014-01-01

    The importance of estrogens in the etiology of breast cancer is widely recognized. Estrogen-induced oxidative stress has been implicated in this carcinogenic process. Resveratrol (Res), a natural antioxidant phytoestrogen has chemopreventive effects against a variety of illnesses including cancer. The objective of the present study was to characterize the mechanism(s) of Res-mediated protection against estrogen-induced breast carcinogenesis. Female August Copenhagen Irish rats were treated with 17β-estradiol (E2), Res and Res + E2 for 8 months. Cotreatment of rats with Res and E2 inhibited E2-mediated proliferative changes in mammary tissues and significantly increased tumor latency and reduced E2-induced breast tumor development. Resveratrol treatment alone or in combination with E2 significantly upregulated expression of nuclear factor erythroid 2-related factor 2 (NRF2) in mammary tissues. Expression of NRF2-regulated antioxidant genes NQO1, SOD3 and OGG1 that are involved in protection against oxidative DNA damage was increased in Res- and Res + E2-treated mammary tissues. Resveratrol also prevented E2-mediated inhibition of detoxification genes AOX1 and FMO1. Inhibition of E2-mediated alterations in NRF2 promoter methylation and expression of NRF2 targeting miR-93 after Res treatment indicated Res-mediated epigenetic regulation of NRF2 during E2-induced breast carcinogenesis. Resveratrol treatment also induced apoptosis and inhibited E2-mediated increase in DNA damage in mammary tissues. Increased apoptosis and decreased DNA damage, cell migration, colony and mammosphere formation in Res- and Res + E2-treated MCF-10A cells suggested a protective role of Res against E2-induced mammary carcinogenesis. Small-interfering RNA-mediated silencing of NRF2 inhibited Res-mediated preventive effects on the colony and mammosphere formation. Taken together, these results suggest that Res inhibits E2-induced breast carcinogenesis via induction of NRF2-mediated protective

  18. Infection-Mediated Priming of Phagocytes Protects against Lethal Secondary Aspergillus fumigatus Challenge

    PubMed Central

    Savers, Amélie; Rasid, Orhan; Parlato, Marianna; Brock, Matthias; Jouvion, Gregory; Ryffel, Bernhard; Cavaillon, Jean-Marc; Eberl, Gerard; Ibrahim-Granet, Oumaïma

    2016-01-01

    Phagocytes restrict the germination of Aspergillus fumigatus conidia and prevent the establishment of invasive pulmonary aspergillosis in immunecompetent mice. Here we report that immunecompetent mice recovering from a primary A. fumigatus challenge are protected against a secondary lethal challenge. Using RAGγc knock-out mice we show that this protection is independent of T, B and NK cells. In protected mice, lung phagocytes are recruited more rapidly and are more efficient in conidial phagocytosis and killing. Protection was also associated with an enhanced expression of CXCR2 and Dectin-1 on bone marrow phagocytes. We also show that protective lung cytokine and chemokine responses are induced more rapidly and with enhanced dynamics in protected mice. Our findings support the hypothesis that following a first encounter with a non-lethal dose of A. fumigatus conidia, the innate immune system is primed and can mediate protection against a secondary lethal infection. PMID:27078879

  19. Moderate-Intensity Physical Exercise Protects Against Experimental 6-Hydroxydopamine-Induced Hemiparkinsonism Through Nrf2-Antioxidant Response Element Pathway.

    PubMed

    Aguiar, Aderbal Silva; Duzzioni, Marcelo; Remor, Aline Pertile; Tristão, Fabrine Sales Massafera; Matheus, Filipe C; Raisman-Vozari, Rita; Latini, Alexandra; Prediger, Rui Daniel

    2016-02-01

    Exercise improves the motor symptoms of patients with Parkinson disease in a palliative manner. Existing evidence demonstrates that exercise induces neuroprotection based on the neurotrophic properties. We investigated the effect of exercise on mitochondrial physiology and oxidative stress in an animal model of hemiparkinsonism. C57BL/6 mice completed a 6-week exercise program on a treadmill. We injected 6-hydroxydopamine (6-OHDA; 4 μg/2 μl) into the midstriatum. The animals progressively developed bradykinesia and R(-)-apomorphine-induced rotations that were attenuated by exercise. Transcriptional activation of protective genes is mediated by the antioxidant response element (ARE). Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) binds to ARE. We investigated the Nrf2-ARE pathway in the striatum of animals. Exercise protected 6-OHDA-induced loss of tyrosine hydroxylase immunolabeling and activated the Nrf2-ARE pathway in the nigrostriatal pathway. Exercise stimulated mitochondrial biogenesis in the striatum of animals that was more resistant to oxidant 6-OHDA and nitric oxide donor (±)-S-nitroso-N-acetylpenicillamine. In mice, exercise activated Nrf2-ARE signaling in the nigrostriatal pathway that was protective against the development of hemiparkinsonism.

  20. Enhanced stability of tristetraprolin mRNA protects mice against immune-mediated inflammatory pathologies

    PubMed Central

    Patial, Sonika; Curtis, Alan D.; Lai, Wi S.; Stumpo, Deborah J.; Hill, Georgette D.; Flake, Gordon P.; Mannie, Mark D.; Blackshear, Perry J.

    2016-01-01

    Tristetraprolin (TTP) is an inducible, tandem zinc-finger mRNA binding protein that binds to adenylate-uridylate–rich elements (AREs) in the 3′-untranslated regions (3′UTRs) of specific mRNAs, such as that encoding TNF, and increases their rates of deadenylation and turnover. Stabilization of Tnf mRNA and other cytokine transcripts in TTP-deficient mice results in the development of a profound, chronic inflammatory syndrome characterized by polyarticular arthritis, dermatitis, myeloid hyperplasia, and autoimmunity. To address the hypothesis that increasing endogenous levels of TTP in an intact animal might be beneficial in the treatment of inflammatory diseases, we generated a mouse model (TTPΔARE) in which a 136-base instability motif in the 3′UTR of TTP mRNA was deleted in the endogenous genetic locus. These mice appeared normal, but cultured fibroblasts and macrophages derived from them exhibited increased stability of the otherwise highly labile TTP mRNA. This resulted in increased TTP protein expression in LPS-stimulated macrophages and increased levels of TTP protein in mouse tissues. TTPΔARE mice were protected from collagen antibody-induced arthritis, exhibited significantly reduced inflammation in imiquimod-induced dermatitis, and were resistant to induction of experimental autoimmune encephalomyelitis, presumably by dampening the excessive production of proinflammatory mediators in all cases. These data suggest that increased systemic levels of TTP, secondary to increased stability of its mRNA throughout the body, can be protective against inflammatory disease in certain models and might be viewed as an attractive therapeutic target for the treatment of human inflammatory diseases. PMID:26831084

  1. Eosinophils mediate protective immunity against secondary nematode infection.

    PubMed

    Huang, Lu; Gebreselassie, Nebiat G; Gagliardo, Lucille F; Ruyechan, Maura C; Luber, Kierstin L; Lee, Nancy A; Lee, James J; Appleton, Judith A

    2015-01-01

    Eosinophils are versatile cells that regulate innate and adaptive immunity, influence metabolism and tissue repair, and contribute to allergic lung disease. Within the context of immunity to parasitic worm infections, eosinophils are prominent yet highly varied in function. We have shown previously that when mice undergo primary infection with the parasitic nematode Trichinella spiralis, eosinophils play an important immune regulatory role that promotes larval growth and survival in skeletal muscle. In this study, we aimed to address the function of eosinophils in secondary infection with T. spiralis. By infecting eosinophil-ablated mice, we found that eosinophils are dispensable for immunity that clears adult worms or controls fecundity in secondary infection. In contrast, eosinophil ablation had a pronounced effect on secondary infection of skeletal muscle by migratory newborn larvae. Restoring eosinophils to previously infected, ablated mice caused them to limit muscle larvae burdens. Passive immunization of naive, ablated mice with sera or Ig from infected donors, together with transfer of eosinophils, served to limit the number of newborn larvae that migrated in tissue and colonized skeletal muscle. Results from these in vivo studies are consistent with earlier findings that eosinophils bind to larvae in the presence of Abs in vitro. Although our previous findings showed that eosinophils protect the parasite in primary infection, these new data show that eosinophils protect the host in secondary infection.

  2. Eosinophils mediate protective immunity against secondary nematode infection1

    PubMed Central

    Huang, Lu; Gebreselassie, Nebiat G.; Gagliardo, Lucille F.; Ruyechan, Maura C.; Luber, Kierstin L.; Lee, Nancy A.; Lee, James J.; Appleton, Judith A.

    2014-01-01

    Eosinophils are versatile cells that regulate innate and adaptive immunity, influence metabolism and tissue repair, and contribute to allergic lung disease. Within the context of immunity to parasitic worm infections, eosinophils are prominent yet highly varied in function. We have shown previously that when mice undergo primary infection with the parasitic nematode, Trichinella spiralis, eosinophils play an important, immune regulatory role that promotes larval growth and survival in skeletal muscle. In this study, we aimed to address the function of eosinophils in secondary infection with T. spiralis. By infecting eosinophil-ablated mice, we found that eosinophils are dispensable for immunity that clears adult worms or controls fecundity in secondary infection. In contrast, eosinophil ablation had a pronounced effect on secondary infection of skeletal muscle by migratory newborn larvae. Restoring eosinophils to previously infected, ablated mice caused them to limit muscle larvae burdens. Passive immunization of naïve, ablated mice with sera or immunoglobulin from infected donors, together with transfer of eosinophils, served to limit the number of newborn larvae that migrated in tissue and colonized skeletal muscle. Results from these in vivo studies are consistent with earlier findings that eosinophils bind to larvae in the presences of antibodies in vitro. Although our previous findings showed that eosinophils protect the parasite in primary infection, these new data show that eosinophils protect the host in secondary infection. PMID:25429065

  3. Oxidative stress correlates with Wolbachia-mediated antiviral protection in Wolbachia-Drosophila associations.

    PubMed

    Wong, Zhee Sheen; Brownlie, Jeremy C; Johnson, Karyn N

    2015-05-01

    Wolbachia mediates antiviral protection in insect hosts and is being developed as a potential biocontrol agent to reduce the spread of insect-vectored viruses. Definition of the molecular mechanism that generates protection is important for understanding the tripartite interaction between host insect, Wolbachia, and virus. Elevated oxidative stress was previously reported for a mosquito line experimentally infected with Wolbachia, suggesting that oxidative stress is important for Wolbachia-mediated antiviral protection. However, Wolbachia experimentally introduced into mosquitoes impacts a range of host fitness traits, some of which are unrelated to antiviral protection. To explore whether elevated oxidative stress is associated with antiviral protection in Wolbachia-infected insects, we analyzed oxidative stress of five Wolbachia-infected Drosophila lines. In flies infected with protective Wolbachia strains, hydrogen peroxide concentrations were 1.25- to 2-fold higher than those in paired fly lines cured of Wolbachia infection. In contrast, there was no difference in the hydrogen peroxide concentrations in flies infected with nonprotective Wolbachia strains compared to flies cured of Wolbachia infection. Using a Drosophila mutant that produces increased levels of hydrogen peroxide, we investigated whether flies with high levels of endogenous reactive oxygen species had altered responses to virus infection and found that flies with high levels of endogenous hydrogen peroxide were less susceptible to virus-induced mortality. Taken together, these results suggest that elevated oxidative stress correlates with Wolbachia-mediated antiviral protection in natural Drosophila hosts.

  4. Stability of efferent-mediated protection against acoustic overexposure with long maintenance under barbiturate anaesthesia.

    PubMed

    Rajan, R

    1996-01-01

    When anaesthetized animals are maintained over a long period, crossed-cochlear suppressive and enhancement-in-noise effects mediated by the olivocochlear bundle (OCB), as well as some OCB neuronal responses, show time-dependent variations. The present study determined if there were any such changes in OCB-mediated crossed-cochlear protection against compound action potential (CAP) threshold losses caused by a standard loud sound exposure at 11 kHz, presented under conditions either not evoking OCB-mediated protection (i.e. monaural exposure) or evoking protection (binaural exposure). Maintaining animals for periods up to approximately 30 h from initial anaesthetization resulted in non-significant changes in pre-exposure CAP thresholds. There were also only small changes over select frequency ranges in threshold losses caused by the monaural or binaural loud sound, after a single exposure as well as when the testing of OCB function was extended to examine effects after dual successive exposures, the latter result being determined by application of a previously described additivity model. The features of OCB-mediated protection also showed good stability over the long maintenance. These results are discussed as providing further circumstantial evidence that protection is mediated by a different OCB subcomponent to that/those responsible for other OCB-mediated crossed-cochlear effects. In general, the results show that the barbiturate anaesthetic used here does not significantly modulate the crossed-cochlear OCB effect of protection, even though it has been shown elsewhere to significantly depress other crossed-cochlear OCB effects.

  5. IL-17A-Mediated Protection against Acanthamoeba Keratitis

    PubMed Central

    Suryawanshi, Amol; Cao, Zhiyi; Sampson, James F.

    2014-01-01

    Acanthamoeba keratitis (AK) is a very painful and vision impairing infection of the cornea that is difficult to treat. Although past studies have indicated a critical role of neutrophils and macrophages in AK, the relative contribution of the proinflammatory cytokine, IL-17A, that is essential for migration, activation and function of these cells into the cornea is poorly defined. Moreover, the role of the adaptive immune response, particularly the contribution of CD4+ T cell subsets, Th17 and Treg cells, in AK is yet to be understood. In this report, using a mouse corneal intrastromal injection-induced AK model, we show that Acanthamoeba infection induces a strong CD4+ T effector and regulatory T cell response in the cornea as well as local draining lymph nodes (dLN). We also demonstrate that corneal Acanthamoeba infection induces IL-17A expression and that IL-17A is critical for host protection against severe AK pathology. Accordingly, IL-17A neutralization in Acanthamoeba-infected wild-type mice or Acanthamoeba infection of mice lacking IL-17A resulted in a significantly increased corneal AK pathology, increased migration of inflammatory cells at the site of inflammation and a significant increase in the effector CD4+ T cell response in dLN. Thus, in sharp contrast to other corneal infections such as herpes and P. aeruginosa keratitis where IL-17A exacerbates corneal pathology and inflammation, findings presented in this manuscript suggest that IL-17A production after Acanthamoeba infection plays an important role in host protection against invading parasites. PMID:25505284

  6. IL-17A-mediated protection against Acanthamoeba keratitis.

    PubMed

    Suryawanshi, Amol; Cao, Zhiyi; Sampson, James F; Panjwani, Noorjahan

    2015-01-15

    Acanthamoeba keratitis (AK) is a very painful and vision-impairing infection of the cornea that is difficult to treat. Although past studies have indicated a critical role of neutrophils and macrophages in AK, the relative contribution of the proinflammatory cytokine, IL-17A, that is essential for migration, activation, and function of these cells into the cornea is poorly defined. Moreover, the role of the adaptive immune response, particularly the contribution of CD4(+) T cell subsets, Th17 and regulatory T cells , in AK is yet to be understood. In this report, using a mouse corneal intrastromal injection-induced AK model, we show that Acanthamoeba infection induces a strong CD4(+) T effector and regulatory T cell response in the cornea and local draining lymph nodes. We also demonstrate that corneal Acanthamoeba infection induces IL-17A expression and that IL-17A is critical for host protection against severe AK pathology. Accordingly, IL-17A neutralization in Acanthamoeba-infected wild-type mice or Acanthamoeba infection of mice lacking IL-17A resulted in a significantly increased corneal AK pathology, increased migration of inflammatory cells at the site of inflammation, and a significant increase in the effector CD4(+) T cell response in draining lymph nodes. Thus, in sharp contrast with other corneal infections such as herpes and Pseudomonas aeruginosa keratitis where IL-17A exacerbates corneal pathology and inflammation, the findings presented in this article suggest that IL-17A production after Acanthamoeba infection plays an important role in host protection against invading parasites.

  7. Antibody-Mediated Protection Against SHIV Challenge Includes Systemic Clearance of Distal Virus

    PubMed Central

    Liu, Jinyan; Ghneim, Khader; Sok, Devin; Bosche, William J.; Li, Yuan; Chipriano, Elizabeth; Berkemeier, Brian; Oswald, Kelli; Borducchi, Erica; Cabral, Crystal; Peter, Lauren; Brinkman, Amanda; Shetty, Mayuri; Jimenez, Jessica; Mondesir, Jade; Lee, Benjamin; Giglio, Patricia; Chandrashekar, Abishek; Abbink, Peter; Colantonio, Arnaud; Gittens, Courtney; Baker, Chantelle; Wagner, Wendeline; Lewis, Mark G.; Li, Wenjun; Sekaly, Rafick-Pierre; Lifson, Jeffrey D.; Burton, Dennis R.; Barouch, Dan H.

    2017-01-01

    HIV-1-specific broadly neutralizing antibodies (bNAbs) can protect rhesus monkeys against simian-human immunodeficiency virus (SHIV) challenge. However, the site of antibody interception of virus and the mechanism of antibody-mediated protection remain unclear. We administered a fully protective dose of the bNAb PGT121 to rhesus monkeys and challenged them intravaginally with SHIV-SF162P3. In PGT121 treated animals, we detected low levels of viral RNA and viral DNA in distal tissues for several days following challenge. Viral RNA positive tissues showed transcriptomic changes indicative of innate immune activation, and cells from these tissues initiated infection following adoptive transfer into naïve hosts. These data demonstrate that bNAb mediated protection against a mucosal virus challenge can involve clearance of infectious virus in distal tissues. PMID:27540005

  8. Activation of glutathione peroxidase via Nrf1 mediates genistein's protection against oxidative endothelial cell injury

    SciTech Connect

    Hernandez-Montes, Eva; Pollard, Susan E.; Vauzour, David; Jofre-Montseny, Laia; Rota, Cristina; Rimbach, Gerald; Weinberg, Peter D.; Spencer, Jeremy P.E. . E-mail: j.p.e.spencer@reading.ac.uk

    2006-08-04

    Cellular actions of isoflavones may mediate the beneficial health effects associated with high soy consumption. We have investigated protection by genistein and daidzein against oxidative stress-induced endothelial injury. Genistein but not daidzein protected endothelial cells from damage induced by oxidative stress. This protection was accompanied by decreases in intracellular glutathione levels that could be explained by the generation of glutathionyl conjugates of the oxidised genistein metabolite, 5,7,3',4'-tetrahydroxyisoflavone. Both isoflavones evoked increased protein expression of {gamma}-glutamylcysteine synthetase-heavy subunit ({gamma}-GCS-HS) and increased cytosolic accumulation and nuclear translocation of Nrf2. However, only genistein led to increases in the cytosolic accumulation and nuclear translocation of Nrf1 and the increased expression of and activity of glutathione peroxidase. These results suggest that genistein-induced protective effects depend primarily on the activation of glutathione peroxidase mediated by Nrf1 activation, and not on Nrf2 activation or increases in glutathione synthesis.

  9. Protective capacities of certain spices against peroxynitrite-mediated biomolecular damage.

    PubMed

    Ho, Su-Chen; Tsai, Tzung-Hsun; Tsai, Po-Jung; Lin, Chih-Cheng

    2008-03-01

    Peroxynitrite, a potent cytotoxic agent, can damage a variety of biomolecules such as proteins, lipids, and DNA, and is considered as one of the major pathological causes of several diseases. Therefore, it would appear likely that interception of peroxynitrite by certain dietary compounds may represent one mechanism by which such foods may exert their beneficial action in vivo. A number of researchers have speculated that certain spices, rich in phenolics, may, conceivably, act as potential protectors against the actions of peroxynitrite. Eight culinary spices including cardamom, cinnamon, cloves, cumin, nutmeg, paprika, rosemary and turmeric were selected for study purposes. Further, the protective effects of methanol extracts of such spices against peroxynitrite-mediated damage to proteins, lipids and DNA were evaluated as determined by these extracts' ability to attenuate the formation of, respectively, nitrotyrosine in albumin, thiobarbiturate acid-reactive substances (TBARS) in liposome and strand breakages for plasmid DNA. All of the tested spices exerted some level of protective ability against peroxynitrite-mediated biomolecular damage. Amongst them, cloves deserve special attention due to their outstanding protective abilities against two of three forms of peroxynitrite-mediated biomolecular damage. Additionally, the phenolic content of certain spices appears to correlate well with such spices' protective effect against peroxynitrite-mediated tyrosine nitration and lipid peroxidation. Such an observation indicates that phenolics present in the spices contributed to such spice-elicited protection against peroxynitrite toxicity.

  10. Amygdala FAAH and anandamide: mediating protection and recovery from stress.

    PubMed

    Gunduz-Cinar, Ozge; Hill, Matthew N; McEwen, Bruce S; Holmes, Andrew

    2013-11-01

    A long-standing literature linking endocannabinoids (ECBs) to stress, fear, and anxiety has led to growing interest in developing novel anxiolytics targeting the ECB system. Following rapid on-demand biosynthesis and degradation upon neuronal activation, the ECB N-arachidonoylethanolamide (anandamide, AEA) is actively degraded by the serine hydrolase enzyme, fatty acid amide hydrolase (FAAH). Exposure to stress rapidly mobilizes FAAH to deplete the signaling pool of AEA and increase neuronal excitability in a key anxiety-mediating region--the basolateral amygdala (BLA). Gene deletion or pharmacological inhibition of FAAH prevents stress-induced reductions in AEA and associated increases in BLA dendritic hypertrophy and anxiety-like behavior. Additionally, inhibition of FAAH facilitates long-term fear extinction and rescues deficient fear extinction in rodent models by enhancing AEA-CB1 (cannabinoid type 1) receptor signaling and synaptic plasticity in the BLA. These preclinical findings propose restoring deficient BLA AEA levels by pharmacologically inhibiting FAAH as a mechanism to therapeutically mitigate the effects of traumatic stress.

  11. Distinct regulatory elements mediate similar expression patterns in the excretory cell of Caenorhabditis elegans.

    PubMed

    Zhao, Zhongying; Fang, Li; Chen, Nansheng; Johnsen, Robert C; Stein, Lincoln; Baillie, David L

    2005-11-18

    Identification of cis-regulatory elements and their binding proteins constitutes an important part of understanding gene function and regulation. It is well accepted that co-expressed genes tend to share transcriptional elements. However, recent findings indicate that co-expression data show poor correlation with co-regulation data even in unicellular yeast. This motivates us to experimentally explore whether it is possible that co-expressed genes are subject to differential regulatory control using the excretory cell of Caenorhabditis elegans as an example. Excretory cell is a functional equivalent of human kidney. Transcriptional regulation of gene expression in the cell is largely unknown. We isolated a 10-bp excretory cell-specific cis-element, Ex-1, from a pgp-12 promoter. The significance of the element has been demonstrated by its capacity of converting an intestine-specific promoter into an excretory cell-specific one. We also isolated a cDNA encoding an Ex-1 binding transcription factor, DCP-66, using a yeast one-hybrid screen. Role of the factor in regulation of pgp-12 expression has been demonstrated both in vitro and in vivo. Search for occurrence of Ex-1 reveals that only a small portion of excretory cell-specific promoters contain Ex-1. Two other distinct cis-elements isolated from two different promoters can also dictate the excretory cell-specific expression but are independent of regulation by DCP-66. The results indicate that distinct regulatory elements are able to mediate the similar expression patterns.

  12. UVR8 mediated plant protective responses under low UV-B radiation leading to photosynthetic acclimation.

    PubMed

    Singh, Suruchi; Agrawal, S B; Agrawal, Madhoolika

    2014-08-01

    The UV-B photoreceptor UVR8 regulates the expression of several genes leading to acclimation responses in plants. Direct role of UVR8 in maintaining the photosynthesis is not defined but it is known to increase the expression of some chloroplastic proteins like SIG5 and ELIP. It provides indirect protection to photosynthesis by regulating the synthesis of secondary metabolites and photomorphogenesis. Signaling cascades controlled by UVR8 mediate many protective responses thus promotes plant acclimation against stress and secures its survival.

  13. Nrf2 Protects Against TWEAK-mediated Skeletal Muscle Wasting

    NASA Astrophysics Data System (ADS)

    Al-Sawaf, Othman; Fragoulis, Athanassios; Rosen, Christian; Kan, Yuet Wai; Sönmez, Tolga Taha; Pufe, Thomas; Wruck, Christoph Jan

    2014-01-01

    Skeletal muscle (SM) regeneration after injury is impaired by excessive inflammation. Particularly, the inflammatory cytokine tumour necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) is a potent inducer of skeletal muscle wasting and fibrosis. In this study we investigated the role of Nrf2, a major regulator of oxidative stress defence, in SM ischemia/reperfusion (I/R) injury and TWEAK induced atrophy. We explored the time-dependent expression of TWEAK after I/R in SM of Nrf2-wildtype (WT) and knockout (KO) mice. Nrf2-KO mice expressed significant higher levels of TWEAK as compared to WT mice. Consequently, Nrf2-KO mice present an insufficient regeneration as compared to Nrf2-WT mice. Moreover, TWEAK stimulation activates Nrf2 in the mouse myoblast cell line C2C12. This Nrf2 activation inhibits TWEAK induced atrophy in C2C12 differentiated myotubes. In summary, we show that Nrf2 protects SM from TWEAK-induced cell death in vitro and that Nrf2-deficient mice therefore have poorer muscle regeneration.

  14. Gut Microbiota Mediates Protection Against Enteropathy Induced by Indomethacin

    PubMed Central

    Xiao, Xue; Nakatsu, Geicho; Jin, Ye; Wong, Sunny; Yu, Jun; Lau, James Y. W.

    2017-01-01

    Non-steroidal anti-inflammatory drugs (NSAIDs) can cause significant small bowel injuries. The role of gut microbiota in this NSAID-induced enteropathy is poorly understood. We studied the dynamic changes in gut microbiota following indomethacin administration in mice, and investigated the effects of these adaptive changes on subsequent NSAID-induced enteropathy. The changes in gut microbiota were studied using 16S rRNA sequencing, and the effects of such changes were investigated using antibiotics and a faecal transplantation model. After indomethacin treatment, significant adaptive changes in gut microbiota were observed, including increased abundance of Firmicutes and decreased abundance in that of Bacteroidetes. Depletion of gut microbiota with antibiotics led to a higher mortality (P = 0.0021) in mice compared to controls. Mice pre-transplanted with adaptively changed microbiota showed less small bowel injury and lower levels of pro-inflammatory cytokines when exposed to indomethacin. In summary, this study identifies adaptive changes in the gut microbiota upon indomethacin administration, which can in turn ameliorate further NSAID-induced injury. The heightened mortality with antibiotic depletion of the adaptively changed microbiota suggests its important role in protecting against such injury. This study provides insight for future efforts to target the microbiota as a therapeutic strategy. PMID:28067296

  15. Review of Rover fuel element protective coating development at Los Alamos

    NASA Technical Reports Server (NTRS)

    Wallace, Terry C.

    1991-01-01

    The Los Alamos Scientific Laboratory (LASL) entered the nuclear propulsion field in 1955 and began work on all aspects of a nuclear propulsion program with a target exhaust temperature of about 2750 K. A very extensive chemical vapor deposition coating technology for preventing catastrophic corrosion of reactor core components by the high temperature, high pressure hydrogen propellant gas was developed. Over the 17-year term of the program, more than 50,000 fuel elements were coated and evaluated. Advances in performance were achieved only through closely coupled interaction between the developing fuel element fabrication and protective coating technologies. The endurance of fuel elements in high temperature, high pressure hydrogen environment increased from several minutes at 2000 K exit gas temperature to 2 hours at 2440 K exit gas temperature in a reactor test and 10 hours at 2350 K exit gas temperature in a hot gas test. The purpose of this paper is to highlight the rationale for selection of coating materials used (NbC and ZrC), identify critical fuel element-coat interactions that had to be modified to increase system performance, and review the evolution of protective coating technology.

  16. Modification of radiobiological effects of 171 MeV protons by elements of physical protection

    NASA Astrophysics Data System (ADS)

    Bulinina, Taisia; Shurshakov, Vyacheslav; Ivanov, Alexander; Molokanov, Alexander

    2016-07-01

    Space radiation includes protons of various energies. Physical protection is effective in the case of low energy protons (50-100 MeV) and becomes insufficient for radiation with a high part of high-energy protons. In the experiment performed on outbred mice, the purpose of the study was to evaluate the radiobiological effect of 171 MeV protons and protons modified by elements of physical protection of the spacecraft, on a complex of indicators of the functional condition of the system hematopoiesis and the central nervous system in 24 hours after irradiation at 20 cGy dose. The spacecraft radiation protection elements used in the experiment were a construction of wet hygiene wipes called a «protective curtain», and a glass plate imitating an ISS window. Mass thickness of the " protective curtain" in terms of water equivalent was ̴ 6,2 g/cm2. Physical shielding along the path of 171 MeV protons increases their linear energy transfer leading to the absorbed dose elevation and strengthening of the radiobiological effect. In the experiment, the two types of shielding together raised the absorbed dose from 20 to 23.2 cGy. Chemically different materials (glass and water in the wipes) were found to exert unequal modifying effects on physical and biological parameters of the proton-irradiated mice. There was a distinct dose-dependent reduction of bone marrow cellularity within the dose range from 20 cGy to 23.2 cGy in 24 hours after exposure. No modifying effect of the radiation protection elements on spontaneous motor activity was discovered when compared with entrance protons. The group of animals protected by the glass plate exhibited normal orientative-trying reactions and weakened grip with the forelimbs. The effects observed in the experiment indicate the necessity to carry out comprehensive radiobiological researches (physical, biological and mathematical) in assessing the effects of physical protection, that are actual for ensuring radiation safety of crews in

  17. Nerve growth factor protects against aluminum-mediated cell death.

    PubMed

    Ohyashiki, Takao; Satoh, Eiko; Okada, Morihiro; Takadera, Tsuneo; Sahara, Masako

    2002-07-15

    In the present study, we examined the effect of two salts of aluminum (Al), aluminum maltolate (Almal) and aluminum chloride (AlCl(3)), on the cell viability of PC12 cells in the absence and presence of nerve growth factor (NGF). A 72-h exposure of PC12 cells to Almal (300 microM) resulted in a marked increase of lactic dehydrogenase (LDH) release from the cells and a decrease of 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) activity. These results indicate that Almal induces a decrease in the cell viability. Under the same conditions, Almal also caused DNA ladder formation and chromatin condensation. In contrast, AlCl(3) did not showed an increased LDH release and a decreased MTT activity in the concentration range of the salt tested (0.1-1 mM). The extent of LDH release and MTT activity decrease induced by Almal treatment closely depended on the amount of Almal incorporated into the cells. An increase in the fluorescence intensity of 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate, di(acetoxymethyl ester) (C-DCDHF-DA) which was loaded into the cell by Almal treatment and its prevention by pyrrolodine dithiocarbamate, a potent antioxidant, suggested that Almal-induced cell death partly proceeds via reactive oxygen species (ROS) production. NGF effectively inhibited the increase of LDH release and the decrease of MTT activity, as well as DNA fragmentation and chromatin condensation. However, NGF did not inhibit the increase of C-DCDHF-DA fluorescence in the cells induced by Almal treatment. From these results, it is suggested that ROS production associated with accumulation of Al is one possible important factor in the onset of Al neurotoxicity via apoptotic cell death and that NGF protects against cell degeneration associated with Al accumulation, but independently of ROS production.

  18. Resveratrol protects adult cardiomyocytes against oxidative stress mediated cell injury.

    PubMed

    Movahed, A; Yu, L; Thandapilly, S J; Louis, X L; Netticadan, T

    2012-11-15

    Recent studies from our laboratory have showed that resveratrol, a polyphenol found predominantly in grapes rendered strong cardioprotection in animal models of heart disease. The cardioprotection which was observed was primarily associated with the ability of resveratrol to reduce oxidative stress in these models. The aim of the current study was to corroborate the role of resveratrol as an inhibitor of oxidative stress and explore the underlying mechanisms of its action in heart disease. For this purpose, we used a cell model of oxidative stress, the hydrogen peroxide (H(2)O(2)) exposed adult rat cardiomyocytes, which was treated with and without resveratrol (30 μM); cardiomyocytes which were not exposed to resveratrol served as controls. Cell injury, cell death and oxidative stress measurements as well as the activities of the major endogenous antioxidants superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were carried out in control and H(2)O(2) exposed cardiomyocytes, treated with and without resveratrol. Pharmacological blockade using specific blockers of the antioxidant enzymes were used to confirm their role in mediating resveratrol action in H(2)O(2) exposed cardiomyocytes. The status of H(2)O(2) and antioxidant enzymes in serum samples from spontaneously hypertensive rats (SHR) treated with and without resveratrol (2.5 mg/kg body weight) was also examined. Our results showed significant cell injury and death in H(2)O(2) exposed cardiomyocytes which was prevented upon resveratrol treatment. SOD and CAT activities were decreased in H(2)O(2) exposed adult rat cardiomyocytes; treatment with resveratrol significantly prevented this reduction. However, GPx activity was not altered in the H(2)O(2) exposed cardiomyocytes in comparison to controls. Pharmacological blockade of SOD and/or CAT prevented the beneficial effect of resveratrol. In SHR, H(2)O(2) levels were increased, but CAT activity was decreased, while SOD remained unchanged

  19. Mediation in Child Protection Cases: An Alternative to the Adversary System.

    ERIC Educational Resources Information Center

    Palmer, Sally E.

    1989-01-01

    Discusses two concerns regarding adverse effects of increased litigation in child protection cases: (1) fallout from the adversarial process on agencies' work with families; and (2) dissonance between the approaches of social workers and lawyers to decision-making about families. Recommends mediation to prevent less serious cases from going to…

  20. Attitudes Toward Wildlife Species Protection: Assessing Moderating and Mediating Effects in the Value-Attitude Relationship

    Treesearch

    Michael A. Tarrant; Alan D. Bright; H. Ken Cordell

    1997-01-01

    Framed in the cognitive hierarchy approach, we examine (1) the mediating effect of general environmental atritudes and (2) the moderating effect of factual wildlife knowledge on the relationship berween values and specific wildlife attitudes (wildlife species protection). These relationships are assessed across four wildlife constituent groups: (I) consumptive users...

  1. Flexible Foam Protection Materials for Constellation Space Suit Element Portable Life Support Subsystem Packaging Study

    NASA Technical Reports Server (NTRS)

    Tang, Henry H.; Orndoff, Evelyne S.; Thomas, Gretchen A.

    2009-01-01

    This paper discusses the effort in evaluating and selecting a light weight impact protection material for the Constellation Space Suit Element (CSSE) Portable Life Support Subsystem (PLSS) conceptual packaging study. A light weight material capable of holding and protecting the components inside the PLSS is required to demonstrate the viability of the flexible PLSS packaging concept. The material needs to distribute, dissipate, and absorb the impact energy of the PLSS falling on the lunar surface. It must also be very robust and function in the extreme lunar thermal vacuum environment for up to one hundred Extravehicular Activity (EVA) missions. This paper documents the performance requirements for selecting a foam protection material, and the methodologies for evaluating commercial off-the-shelf (COTS) foam protection materials. It also presents the materials properties test results and impact drop test results of the various foam materials evaluated in the study. The findings from this study suggest that a foam based flexible protection system is a viable solution for PLSS packaging. However, additional works are needed to optimize COTS foam properties or to develop a composite foam system that will meet all the performance requirements for the CSSE PLSS flexible packaging.

  2. Flexible Foam Protection Materials for Constellation Space Suit Element Portable Life Support Subsystem Packaging Study

    NASA Technical Reports Server (NTRS)

    Tang, Henry H.; Orndoff, Evelyne S.; Thomas, Gretchen A.

    2009-01-01

    This paper discusses the effort in evaluating and selecting a light weight impact protection material for the Constellation Space Suit Element (CSSE) Portable Life Support Subsystem (PLSS) conceptual packaging study. A light weight material capable of holding and protecting the components inside the PLSS is required to demonstrate the viability of the flexible PLSS packaging concept. The material needs to distribute, dissipate, and absorb the impact energy of the PLSS falling on the lunar surface. It must also be very robust and function in the extreme lunar thermal vacuum environment for up to one hundred Extravehicular Activity (EVA) missions. This paper documents the performance requirements for selecting a foam protection material, and the methodologies for evaluating commercial off-the-shelf (COTS) foam protection materials. It also presents the materials properties test results and impact drop test results of the various foam materials evaluated in the study. The findings from this study suggest that a foam based flexible protection system is a viable solution for PLSS packaging. However, additional works are needed to optimize COTS foam properties or to develop a composite foam system that will meet all the performance requirements for the CSSE PLSS flexible packaging.

  3. Parental Mediation Regarding Children's Smartphone Use: Role of Protection Motivation and Parenting Style.

    PubMed

    Hwang, Yoori; Choi, Inho; Yum, Jung-Yoon; Jeong, Se-Hoon

    2017-06-01

    Parental mediation is a type of behavior that could protect children against the negative uses and effects of smartphones. Based on protection motivation theory, this research (a) predicted parental mediation based on parents' threat and efficacy perceptions and (b) predicted threat and efficacy perceptions based on parenting styles and parents' addiction to smartphone use. An online survey of 448 parents of fourth to sixth graders was conducted. Results showed that both restrictive and active parental mediation were predicted by perceived severity, response efficacy, and self-efficacy. With regard to parenting styles, (a) authoritative parenting was positively related to perceived severity as well as response- and self-efficacy, whereas (b) permissive parenting was negatively related to self-efficacy. In addition, parents' addiction was a negative predictor of perceived severity, but a positive predictor of perceived susceptibility.

  4. Toll-like receptor 2-mediated alternative activation of microglia is protective after spinal cord injury.

    PubMed

    Stirling, David P; Cummins, Karen; Mishra, Manoj; Teo, Wulin; Yong, V Wee; Stys, Peter

    2014-03-01

    Improving neurological outcome after spinal cord injury is a major clinical challenge because axons, once severed, do not regenerate but 'dieback' from the lesion site. Although microglia, the immunocompetent cells of the brain and spinal cord respond rapidly to spinal cord injury, their role in subsequent injury or repair remains unclear. To assess the role of microglia in spinal cord white matter injury we used time-lapse two-photon and spectral confocal imaging of green fluorescent protein-labelled microglia, yellow fluorescent protein-labelled axons, and Nile Red-labelled myelin of living murine spinal cord and revealed dynamic changes in white matter elements after laser-induced spinal cord injury in real time. Importantly, our model of acute axonal injury closely mimics the axonopathy described in well-characterized clinically relevant models of spinal cord injury including contusive-, compressive- and transection-based models. Time-lapse recordings revealed that microglia were associated with some acute pathophysiological changes in axons and myelin acutely after laser-induced spinal cord injury. These pathophysiological changes included myelin and axonal spheroid formation, spectral shifts in Nile Red emission spectra in axonal endbulbs detected with spectral microscopy, and 'bystander' degeneration of axons that survived the initial injury, but then succumbed to secondary degeneration. Surprisingly, modulation of microglial-mediated release of neurotoxic molecules failed to protect axons and myelin. In contrast, sterile stimulation of microglia with the specific toll-like receptor 2 agonist Pam2CSK4 robustly increased the microglial response to ablation, reduced secondary degeneration of central myelinated fibres, and induced an alternative (mixed M1:M2) microglial activation profile. Conversely, Tlr2 knock out: Thy1 yellow fluorescent protein double transgenic mice experienced greater axonal dieback than littermate controls. Thus, promoting an alternative

  5. Altering genomic integrity: heavy metal exposure promotes trans-posable element-mediated damage

    PubMed Central

    Morales, Maria E.; Servant, Geraldine; Ade, Catherine; Roy-Enge, Astrid M.

    2015-01-01

    Maintenance of genomic integrity is critical for cellular homeostasis and survival. The active transposable elements (TEs) composed primarily of three mobile element lineages LINE-1, Alu, and SVA comprise approximately 30% of the mass of the human genome. For the past two decades, studies have shown that TEs significantly contribute to genetic instability and that TE-caused damages are associated with genetic diseases and cancer. Different environmental exposures, including several heavy metals, influence how TEs interact with its host genome increasing their negative impact. This mini-review provides some basic knowledge on TEs, their contribution to disease and an overview of the current knowledge on how heavy metals influence TE-mediated damage. PMID:25774044

  6. Three-Dimensional Finite Element Ablative Thermal Response and Thermostructural Design of Thermal Protection Systems

    NASA Technical Reports Server (NTRS)

    Dec, John A.; Braun, Robert D.

    2011-01-01

    A finite element ablation and thermal response program is presented for simulation of three-dimensional transient thermostructural analysis. The three-dimensional governing differential equations and finite element formulation are summarized. A novel probabilistic design methodology for thermal protection systems is presented. The design methodology is an eight step process beginning with a parameter sensitivity study and is followed by a deterministic analysis whereby an optimum design can determined. The design process concludes with a Monte Carlo simulation where the probabilities of exceeding design specifications are estimated. The design methodology is demonstrated by applying the methodology to the carbon phenolic compression pads of the Crew Exploration Vehicle. The maximum allowed values of bondline temperature and tensile stress are used as the design specifications in this study.

  7. Wnt-mediated activation of NeuroD1 and retro-elements during adult neurogenesis.

    PubMed

    Kuwabara, Tomoko; Hsieh, Jenny; Muotri, Alysson; Yeo, Gene; Warashina, Masaki; Lie, Dieter Chichung; Moore, Lynne; Nakashima, Kinichi; Asashima, Makoto; Gage, Fred H

    2009-09-01

    In adult hippocampus, new neurons are continuously generated from neural stem cells (NSCs), but the molecular mechanisms regulating adult neurogenesis remain elusive. We found that Wnt signaling, together with the removal of Sox2, triggered the expression of NeuroD1 in mice. This transcriptional regulatory mechanism was dependent on a DNA element containing overlapping Sox2 and T-cell factor/lymphoid enhancer factor (TCF/LEF)-binding sites (Sox/LEF) in the promoter. Notably, Sox/LEF sites were also found in long interspersed nuclear element 1 (LINE-1) elements, consistent with their critical roles in the transition of NSCs to proliferating neuronal progenitors. Our results describe a previously unknown Wnt-mediated regulatory mechanism that simultaneously coordinates activation of NeuroD1 and LINE-1, which is important for adult neurogenesis and survival of neuronal progenitors. Moreover, the discovery that LINE-1 retro-elements embedded in the mammalian genome can function as bi-directional promoters suggests that Sox/LEF regulatory sites may represent a general mechanism, at least in part, for relaying environmental signals to other nearby loci to promote adult hippocampal neurogenesis.

  8. Using analytic element models to delineate drinking water source protection areas.

    PubMed

    Raymond, Heather A; Bondoc, Michael; McGinnis, John; Metropulos, Kathy; Heider, Pat; Reed, Allison; Saines, Steve

    2006-01-01

    Since 1999, Ohio EPA hydrogeologists have used two analytic element models (AEMs), the proprietary software GFLOW and U.S. EPA's WhAEM, to delineate protection areas for 535 public water systems. Both models now use the GFLOW2001 solution engine, integrate well with Geographic Information System (GIS) technology, have a user-friendly graphical interface, are capable of simulating a variety of complex hydrogeologic settings, and do not rely upon a model grid. These features simplify the modeling process and enable AEMs to bridge the gap between existing simplistic delineation methods and more complex numerical models. Ohio EPA hydrogeologists demonstrated that WhAEM2000 and GFLOW2000 were capable of producing capture zones similar to more widely accepted models by applying the AEMs to eight sites that had been previously delineated using other methods. After the Ohio EPA delineated protection areas using AEMs, more simplistic delineation methods used by other states (volumetric equation and arbitrary fixed radii) were applied to the same water systems to compare the differences between various methods. GIS software and two-tailed paired t-tests were used to quantify the differences in protection areas and analyze the data. The results of this analysis demonstrate that AEMs typically produce significantly different protection areas than the most simplistic delineation methods, in terms of total area and shape. If the volumetric equation had been used instead of AEMs, Ohio would not have protected 265 km2 of critical upgradient area and would have overprotected 269 km2 of primarily downgradient land. Since an increasing number of land-use restrictions are being tied to drinking water protection areas, this analysis has broad policy implications.

  9. A New Element of National Security: Military Forces in Environmental Protection

    DTIC Science & Technology

    1993-04-01

    sort of scenario. If Brazil continues to cut all the rain forests and if the predictions are true, would we deploy military forces to physically stop...U.S.D.A., Forest Service o T I C FI-ECTE ;,’. MAR 14 1994 Faculty Research Advisor,"’ D Mr. J. Dawson Ahalt S The Industrial College of the Armed...Executive Research Project A105 A New Element of National Security: Military Forces in Environmental Protection Harry D. Croft U.S.D.A., Forest Service

  10. Hispidin produced from Phellinus linteus protects against peroxynitrite-mediated DNA damage and hydroxyl radical generation.

    PubMed

    Chen, Wei; Feng, Lina; Huang, Zhaoyi; Su, Hongming

    2012-09-30

    Oxidative stress plays an important role in the progression of many chronic diseases including cardiovascular diseases, diabetes, cancer and neurodegenerative disorders. One such mediator of oxidative stress is peroxynitrite, which is highly toxic to cultured neurons and astrocytes, and has been reported to be involved in the pathogenesis of various types of neuronal diseases. Therefore, searching for natural compounds with peroxynitrite-scavenging activity might be an effective therapy for peroxynitrite-mediated cytotoxicity. Hispidin, a phenolic compound from Phellinus linteus (a medicinal mushroom), has been shown to possess strong antioxidant, anticancer, and antidiabetic properties. However, the astrocyte protective efficacy of hispidin has been not examined. This study was undertaken to investigate whether the astrocyte protective effect of hispidin is associated with inhibition of peroxynitrite-induced DNA damage, a critical event leading to peroxynitrite-mediated cytotoxicity. Our results showed that peroxynitrite can cause DNA damage in φX-174 plasmid DNA and rat primary astrocytes. The presence of hispidin (10-20 μg/ml) was found to significantly inhibit peroxynitrite-induced DNA damage and cytotoxicity. EPR spectroscopy demonstrated that the formation of DMPO-hydroxyl radical adduct (DMPO-OH) from peroxynitrite, and that hispidin potently diminished the adduct signal in a concentration-dependent manner. Taken together, these results demonstrate for the first time that hispidin can protect against peroxynitrite-mediated cytotoxicity, DNA damage and hydroxyl radical formation. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  11. Reconceptualizing Decisional Balance In an Adolescent Sun Protection Intervention: Mediating Effects and Theoretical Interpretations

    PubMed Central

    Adams, Marc A.; Norman, Gregory J.; Hovell, Melbourne F.; Sallis, James F.; Patrick, Kevin

    2008-01-01

    The Transtheoretical model (TTM) integrates principles of operant learning, such as stimulus control and reinforcement, and psychological factors, such as decisional balance. Understanding interrelationships between decisions, behavior, and consequences from multiple theoretical perspectives can advance theory and inform development of more effective interventions. This analysis examined the mediating effects of a special case of the decisional balance construct where the pros of competing behaviors (i.e. sun protection vs. exposure) were measured rather than the pros and cons of the same behavior. Participants included 819 adolescents (10-16 yrs old, 53.5% girls, 58.4% Caucasian) randomized to a 24-month expert system intervention (Sunsmart) or a physical activity and nutrition comparison group. Self-report measures included sun protection behaviors, pros for protection, and pros for exposure. Mediation analysis using latent growth curve models found both the treatment-to-mediator and mediator-to-behavior paths significant for decisional balance, producing an indirect effect of .323 (p < .01) and good model fit (CFI=.973, RMSEA=.055). Multiple strategies for conceptualizing and measuring decisional balance appear to be valid. Results are interpreted from the TTM and operant perspectives. PMID:19290714

  12. Rapid evolution of microbe-mediated protection against pathogens in a worm host

    PubMed Central

    King, Kayla C; Brockhurst, Michael A; Vasieva, Olga; Paterson, Steve; Betts, Alex; Ford, Suzanne A; Frost, Crystal L; Horsburgh, Malcolm J; Haldenby, Sam; Hurst, Gregory DD

    2016-01-01

    Microbes can defend their host against virulent infections, but direct evidence for the adaptive origin of microbe-mediated protection is lacking. Using experimental evolution of a novel, tripartite interaction, we demonstrate that mildly pathogenic bacteria (Enterococcus faecalis) living in worms (Caenorhabditis elegans) rapidly evolved to defend their animal hosts against infection by a more virulent pathogen (Staphylococcus aureus), crossing the parasitism–mutualism continuum. Host protection evolved in all six, independently selected populations in response to within-host bacterial interactions and without direct selection for host health. Microbe-mediated protection was also effective against a broad spectrum of pathogenic S. aureus isolates. Genomic analysis implied that the mechanistic basis for E. faecalis-mediated protection was through increased production of antimicrobial superoxide, which was confirmed by biochemical assays. Our results indicate that microbes living within a host may make the evolutionary transition to mutualism in response to pathogen attack, and that microbiome evolution warrants consideration as a driver of infection outcome. PMID:26978164

  13. Rapid evolution of microbe-mediated protection against pathogens in a worm host.

    PubMed

    King, Kayla C; Brockhurst, Michael A; Vasieva, Olga; Paterson, Steve; Betts, Alex; Ford, Suzanne A; Frost, Crystal L; Horsburgh, Malcolm J; Haldenby, Sam; Hurst, Gregory Dd

    2016-08-01

    Microbes can defend their host against virulent infections, but direct evidence for the adaptive origin of microbe-mediated protection is lacking. Using experimental evolution of a novel, tripartite interaction, we demonstrate that mildly pathogenic bacteria (Enterococcus faecalis) living in worms (Caenorhabditis elegans) rapidly evolved to defend their animal hosts against infection by a more virulent pathogen (Staphylococcus aureus), crossing the parasitism-mutualism continuum. Host protection evolved in all six, independently selected populations in response to within-host bacterial interactions and without direct selection for host health. Microbe-mediated protection was also effective against a broad spectrum of pathogenic S. aureus isolates. Genomic analysis implied that the mechanistic basis for E. faecalis-mediated protection was through increased production of antimicrobial superoxide, which was confirmed by biochemical assays. Our results indicate that microbes living within a host may make the evolutionary transition to mutualism in response to pathogen attack, and that microbiome evolution warrants consideration as a driver of infection outcome.

  14. Insulin Protects Cardiac Myocytes from Doxorubicin Toxicity by Sp1-Mediated Transactivation of Survivin

    PubMed Central

    Lee, Beom Seob; Oh, Jaewon; Kang, Sung Ku; Park, Sungha; Lee, Sang-Hak; Choi, Donghoon; Chung, Ji Hyung; Chung, Youn Wook; Kang, Seok-Min

    2015-01-01

    Insulin inhibits ischemia/reperfusion-induced myocardial apoptosis through the PI3K/Akt/mTOR pathway. Survivin is a key regulator of anti-apoptosis against doxorubicin-induced cardiotoxicity. Insulin increases survivin expression in cardiac myocytes to mediate cytoprotection. However, the mechanism by which survivin mediates the protective effect of insulin against doxorubicin-associated injury remains to be determined. In this study, we demonstrated that pretreatment of H9c2 cardiac myocytes with insulin resulted in a significant decrease in doxorubicin-induced apoptotic cell death by reducing cytochrome c release and caspase-3 activation. Doxorubicin-induced reduction of survivin mRNA and protein levels was also significantly perturbed by insulin pretreatment. Reducing survivin expression with survivin siRNA abrogated insulin-mediated inhibition of caspase-3 activation, suggesting that insulin signals to survivin inhibited caspase-3 activation. Interestingly, pretreatment of H9c2 cells with insulin or MG132, a proteasome inhibitor, inhibited doxorubicin-induced degradation of the transcription factor Sp1. ChIP assay showed that pretreatment with insulin inhibited doxorubicin-stimulated Sp1 dissociation from the survivin promoter. Finally using pharmacological inhibitors of the PI3K pathway, we showed that insulin-mediated activation of the PI3K/Akt/mTORC1 pathway prevented doxorubicin-induced proteasome-mediated degradation of Sp1. Taken together, insulin pretreatment confers a protective effect against doxorubicin-induced cardiotoxicity by promoting Sp1-mediated transactivation of survivin to inhibit apoptosis. Our study is the first to define a role for survivin in cellular protection by insulin against doxorubicin-associated injury and show that Sp1 is a critical factor in the transcriptional regulation of survivin. PMID:26271039

  15. Dimethyl Sulfoxide Protects Escherichia coli from Rapid Antimicrobial-Mediated Killing

    PubMed Central

    Mi, Hongfei; Wang, Dai; Xue, Yunxin; Zhang, Zhi; Hong, Yuzhi; Drlica, Karl

    2016-01-01

    The contribution of reactive oxygen species (ROS) to antimicrobial lethality was examined by treating Escherichia coli with dimethyl sulfoxide (DMSO), an antioxidant solvent frequently used in antimicrobial studies. DMSO inhibited killing by ampicillin, kanamycin, and two quinolones and had little effect on MICs. DMSO-mediated protection correlated with decreased ROS accumulation and provided evidence for ROS-mediated programmed cell death. These data support the contribution of ROS to antimicrobial lethality and suggest caution when using DMSO-dissolved antimicrobials for short-time killing assays. PMID:27246776

  16. Spatio-temporal requirements for transposable element piRNA-mediated silencing during Drosophila oogenesis

    PubMed Central

    Dufourt, Jérémy; Dennis, Cynthia; Boivin, Antoine; Gueguen, Nathalie; Théron, Emmanuelle; Goriaux, Coline; Pouchin, Pierre; Ronsseray, Stéphane; Brasset, Emilie; Vaury, Chantal

    2014-01-01

    During Drosophila oogenesis, transposable element (TE) repression involves the Piwi-interacting RNA (piRNA) pathway which ensures genome integrity for the next generation. We developed a transgenic model to study repression of the Idefix retrotransposon in the germline. Using a candidate gene KD-approach, we identified differences in the spatio-temporal requirements of the piRNA pathway components for piRNA-mediated silencing. Some of them (Aub, Vasa, Spn-E) are necessary in very early stages of oogenesis within the germarium and appear to be less important for efficient TE silencing thereafter. Others (Piwi, Ago3, Mael) are required at all stages of oogenesis. Moreover, during early oogenesis, in the dividing cysts within the germarium, Idefix anti-sense transgenes escape host control, and this is associated with very low piwi expression. Silencing of P-element-based transgenes is also strongly weakened in these cysts. This region, termed the ‘Piwiless pocket’ or Pilp, may ensure that new TE insertions occur and are transmitted to the next generation, thereby contributing to genome dynamics. In contrast, piRNA-mediated silencing is strong in germline stem cells in which TE mobilization is tightly repressed ensuring the continued production of viable germline cysts. PMID:24288375

  17. Spatio-temporal requirements for transposable element piRNA-mediated silencing during Drosophila oogenesis.

    PubMed

    Dufourt, Jérémy; Dennis, Cynthia; Boivin, Antoine; Gueguen, Nathalie; Théron, Emmanuelle; Goriaux, Coline; Pouchin, Pierre; Ronsseray, Stéphane; Brasset, Emilie; Vaury, Chantal

    2014-02-01

    During Drosophila oogenesis, transposable element (TE) repression involves the Piwi-interacting RNA (piRNA) pathway which ensures genome integrity for the next generation. We developed a transgenic model to study repression of the Idefix retrotransposon in the germline. Using a candidate gene KD-approach, we identified differences in the spatio-temporal requirements of the piRNA pathway components for piRNA-mediated silencing. Some of them (Aub, Vasa, Spn-E) are necessary in very early stages of oogenesis within the germarium and appear to be less important for efficient TE silencing thereafter. Others (Piwi, Ago3, Mael) are required at all stages of oogenesis. Moreover, during early oogenesis, in the dividing cysts within the germarium, Idefix anti-sense transgenes escape host control, and this is associated with very low piwi expression. Silencing of P-element-based transgenes is also strongly weakened in these cysts. This region, termed the 'Piwiless pocket' or Pilp, may ensure that new TE insertions occur and are transmitted to the next generation, thereby contributing to genome dynamics. In contrast, piRNA-mediated silencing is strong in germline stem cells in which TE mobilization is tightly repressed ensuring the continued production of viable germline cysts.

  18. Erythropoietin-mediated tissue protection: reducing collateral damage from the primary injury response.

    PubMed

    Brines, M; Cerami, A

    2008-11-01

    In its classic hormonal role, erythropoietin (EPO) is produced by the kidney and regulates the number of erythrocytes within the circulation to provide adequate tissue oxygenation. EPO also mediates other effects directed towards optimizing oxygen delivery to tissues, e.g. modulating regional blood flow and reducing blood loss by promoting thrombosis within damaged vessels. Over the past 15 years, many unexpected nonhaematopoietic functions of EPO have been identified. In these more recently appreciated nonhormonal roles, locally-produced EPO signals through a different receptor isoform and is a major molecular component of the injury response, in which it counteracts the effects of pro-inflammatory cytokines. Acutely, EPO prevents programmed cell death and reduces the development of secondary, pro-inflammatory cytokine-induced injury. Within a longer time frame, EPO provides trophic support to enable regeneration and healing. As the region immediately surrounding damage is typically relatively deficient in endogenous EPO, administration of recombinant EPO can provide increased tissue protection. However, effective use of EPO as therapy for tissue injury requires higher doses than for haematopoiesis, potentially triggering serious adverse effects. The identification of a tissue-protective receptor isoform has facilitated the engineering of nonhaematopoietic, tissue-protective EPO derivatives, e.g. carbamyl EPO, that avoid these complications. Recently, regions within the EPO molecule mediating tissue protection have been identified and this has enabled the development of potent tissue-protective peptides, including some mimicking EPO's tertiary structure but unrelated in primary sequence.

  19. Sulforaphane protects Microcystin-LR-induced toxicity through activation of the Nrf2-mediated defensive response

    SciTech Connect

    Gan Nanqin; Mi Lixin; Sun Xiaoyun; Dai Guofei; Chung Funglung; Song Lirong

    2010-09-01

    Microcystins (MCs), a cyclic heptapeptide hepatotoxins, are mainly produced by the bloom-forming cyanobacerium Microcystis, which has become an environmental hazard worldwide. Long term consumption of MC-contaminated water may induce liver damage, liver cancer, and even human death. Therefore, in addition to removal of MCs in drinking water, novel strategies that prevent health damages are urgently needed. Sulforaphane (SFN), a natural-occurring isothiocyanate from cruciferous vegetables, has been reported to reduce and eliminate toxicities from xenobiotics and carcinogens. The purpose of the present study was to provide mechanistic insights into the SFN-induced antioxidative defense system against MC-LR-induced cytotoxicity. We performed cell viability assays, including MTS assay, colony formation assay and apoptotic cell sorting, to study MC-LR-induced cellular damage and the protective effects by SFN. The results showed that SFN protected MC-LR-induced damages at a nontoxic and physiological relevant dose in HepG2, BRL-3A and NIH 3 T3 cells. The protection was Nrf2-mediated as evident by transactivation of Nrf2 and activation of its downstream genes, including NQO1 and HO-1, and elevated intracellular GSH level. Results of our studies indicate that pretreatment of cells with 10 {mu}M SFN for 12 h significantly protected cells from MC-LR-induced damage. SFN-induced protective response was mediated through Nrf2 pathway.

  20. Transposase-Mediated Excision, Conjugative Transfer, and Diversity of ICE6013 Elements in Staphylococcus aureus.

    PubMed

    Sansevere, Emily A; Luo, Xiao; Park, Joo Youn; Yoon, Sunghyun; Seo, Keun Seok; Robinson, D Ashley

    2017-04-15

    ICE6013 represents one of two families of integrative conjugative elements (ICEs) identified in the pan-genome of the human and animal pathogen Staphylococcus aureus Here we investigated the excision and conjugation functions of ICE6013 and further characterized the diversity of this element. ICE6013 excision was not significantly affected by growth, temperature, pH, or UV exposure and did not depend on recA The IS30-like DDE transposase (Tpase; encoded by orf1 and orf2) of ICE6013 must be uninterrupted for excision to occur, whereas disrupting three of the other open reading frames (ORFs) on the element significantly affects the level of excision. We demonstrate that ICE6013 conjugatively transfers to different S. aureus backgrounds at frequencies approaching that of the conjugative plasmid pGO1. We found that excision is required for conjugation, that not all S. aureus backgrounds are successful recipients, and that transconjugants acquire the ability to transfer ICE6013 Sequencing of chromosomal integration sites in serially passaged transconjugants revealed a significant integration site preference for a 15-bp AT-rich palindromic consensus sequence, which surrounds the 3-bp target site that is duplicated upon integration. A sequence analysis of ICE6013 from different host strains of S. aureus and from eight other species of staphylococci identified seven divergent subfamilies of ICE6013 that include sequences previously classified as a transposon, a plasmid, and various ICEs. In summary, these results indicate that the IS30-like Tpase functions as the ICE6013 recombinase and that ICE6013 represents a diverse family of mobile genetic elements that mediate conjugation in staphylococci.IMPORTANCE Integrative conjugative elements (ICEs) encode the abilities to integrate into and excise from bacterial chromosomes and plasmids and mediate conjugation between bacteria. As agents of horizontal gene transfer, ICEs may affect bacterial evolution. ICE6013 represents one

  1. Protective effect of vitamin C against the ethanol mediated toxic effects on human brain glial cells.

    PubMed

    Sánchez-Moreno, Concepción; Paniagua, Manuel; Madrid, Antonio; Martín, Antonio

    2003-10-01

    It is now known that chronic consumption of excessive amounts of alcohol is a major source of social and medical problems. Ethanol-mediated glial cell activation may lead to neuron damage in many ways, including the formation of free radicals and production of pro-inflammatory molecules. Vitamin C (vit-C) is an essential dietary nutrient required as a co-factor for many enzymes and a very efficient antioxidant, protecting cells against free radical-mediated damage. The objective of this study was to evaluate the protective effects of vit-C on glial cell activation and viability against ethanol-mediated toxicity. Human brain astrocyte cells (HA) were exposed to ethanol (0, 50, and 350 mmol/L) for 24 h. We found that glial cells incubated with different concentrations of vit-C increase their vit-C in a dose-dependent manner. HA incubated with 0, 50 or 350 mmol/L of ethanol for up to 24 h showed toxic effects that were proportional to the levels of ethanol in the medium, HA showed increased levels of heat shock protein (Hsp70). However, cells enriched with vit-C before being exposed to ethanol, were better protected against the alcohol-mediated toxicity than non-supplemented cells, and showed significantly lower concentrations of Hsp70. Ethanol also caused increased expression of cyclooxygenase-2 (COX-2) and synthesis of prostaglandin E2 (PGE2), which were reduced by vit-C. In summary, HA supplemented with vit-C were significantly more resistant to the ethanol-mediated toxic effects.

  2. The protective effect of a helmet in three bicycle accidents--A finite element study.

    PubMed

    Fahlstedt, Madelen; Halldin, Peter; Kleiven, Svein

    2016-06-01

    There is some controversy regarding the effectiveness of helmets in preventing head injuries among cyclists. Epidemiological, experimental and computer simulation studies have suggested that helmets do indeed have a protective effect, whereas other studies based on epidemiological data have argued that there is no evidence that the helmet protects the brain. The objective of this study was to evaluate the protective effect of a helmet in single bicycle accident reconstructions using detailed finite element simulations. Strain in the brain tissue, which is associated with brain injuries, was reduced by up to 43% for the accident cases studied when a helmet was included. This resulted in a reduction of the risk of concussion of up to 54%. The stress to the skull bone went from fracture level of 80 MPa down to 13-16 MPa when a helmet was included and the skull fracture risk was reduced by up to 98% based on linear acceleration. Even with a 10% increased riding velocity for the helmeted impacts, to take into account possible increased risk taking, the risk of concussion was still reduced by up to 46% when compared with the unhelmeted impacts with original velocity. The results of this study show that the brain injury risk and risk of skull fracture could have been reduced in these three cases if a helmet had been worn. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Elemental conservation units: communicating extinction risk without dictating targets for protection.

    PubMed

    Wood, Chris C; Gross, Mart R

    2008-02-01

    Conservation biologists mostly agree on the need to identify and protect biodiversity below the species level but have not yet resolved the best approach. We addressed 2 issues relevant to this debate. First, we distinguished between the abstract goal of preserving the maximum amount of unique biodiversity and the pragmatic goal of minimizing the loss of ecological goods and services given that further loss of biodiversity seems inevitable. Second, we distinguished between the scientific task of assessing extinction risk and the normative task of choosing targets for protection. We propose that scientific advice on extinction risk be given at the smallest meaningful scale: the elemental conservation unit (ECU). An ECU is a demographically isolated population whose probability of extinction over the time scale of interest (say 100 years) is not substantially affected by natural immigration from other populations. Within this time frame, the loss of an ECU would be irreversible without human intervention. Society's decision to protect an ECU ought to reflect human values that have social, economic, and political dimensions. Scientists can best inform this decision by providing advice about the probability that an ECU will be lost and the ecological and evolutionary consequences of that loss in a form that can be integrated into landscape planning. The ECU approach provides maximum flexibility to decision makers and ensures that the scientific task of assessing extinction risk informs, but remains distinct from, the normative social challenge of setting conservation targets.

  4. The Effect of Preventive, Therapeutic and Protective Exercises on Hippocampal Memory Mediators in Stressed Rats

    PubMed Central

    Radahmadi, Maryam; Hosseini, Nasrin; Alaei, Hojjatallah; Sharifi, Mohammad Reza

    2016-01-01

    Background Exercise plays a significant role in learning and memory. The present study focuses on the hippocampal corticosterone (CORT), interleukin-1 beta (IL-1β), glucose, and brain-derived neurotrophic factor (BDNF) levels in preventive, therapeutic, and protective exercises in stressful conditions. Methods Forty male rats were randomly divided into four groups: the control group and the preventive, therapeutic, and protective exercise groups. The treadmill running was applied at a speed of 20–21m/min and a chronic stress of 6 hours/day for 21 days. Subsequently, the variables were measured in the hippocampus. Results The findings revealed that the hippocampal CORT levels in the preventive exercise group had a significant enhancement compared to the control group. In the protective and particularly the therapeutic exercise groups, the hippocampal CORT levels declined. Furthermore, the hippocampal BDNF levels in the preventive and the therapeutic exercise groups indicated significantly decreased and increased, respectively, in comparison with the control group. In the preventive exercise group, however, the hippocampal glucose level turned out to be substantially higher than that in the control group. Conclusion It appears that the therapeutic exercise group had the best exercise protocols for improving the hippocampal memory mediators in the stress conditions. By contrast, the preventive exercise group could not improve these mediators that had been altered by stress. It is suggested that exercise time, compared to stress, can be considered as a crucial factor in the responsiveness of memory mediators. PMID:27904422

  5. Free radical scavenging, DNA protection, and inhibition of lipid peroxidation mediated by uric acid.

    PubMed

    Stinefelt, Beth; Leonard, Stephen S; Blemings, Kenneth P; Shi, Xianglin; Klandorf, Hillar

    2005-01-01

    Uric acid (UA) has been proposed to be the dominant antioxidant in birds. The objective of this study was to investigate the quenching effect of varying concentrations of UA, including those found in avian plasma, on specific reactive oxygen species (ROS) and to determine the ability of UA to protect DNA and cellular membranes from ROS-mediated damage. Hydroxyl (OH) and superoxide (O2-) radicals were detected by electron spin resonance (ESR) and their presence was reduced following addition of UA (p <0.05) in a concentration-dependent manner. UA inhibited hydroxyl-mediated DNA damage, indicated by the presence of more precise, dense bands of lambda Hind III DNA after agarose gel electrophoresis and ethidium bromide staining (p <0.05). Lipid peroxidation of silica-exposed RAW 264.7 cell membranes was diminished (p <0.02) after addition of UA to the cell incubation mixture. These studies demonstrate that UA scavenges hydroxyl and superoxide radicals and protects against DNA damage and lipid peroxidation. These results indicate specific antioxidant protection that UA may afford birds against ROS-mediated damage.

  6. Abdominal adiposity is not a mediator of the protective effect of Mediterranean diet on colorectal cancer.

    PubMed

    Fasanelli, Francesca; Zugna, Daniela; Giraudo, Maria Teresa; Krogh, Vittorio; Grioni, Sara; Panico, Salvatore; Mattiello, Amalia; Masala, Giovanna; Caini, Saverio; Tumino, Rosario; Frasca, Graziella; Sciannameo, Veronica; Ricceri, Fulvio; Sacerdote, Carlotta

    2017-05-15

    Adherence to the Mediterranean diet (MD) has a preventive effect on colorectal cancer (CRC). Several biological mechanisms have been hypothesized to explain this effect, but the involvement of clinical mediators has not been experimentally proven. We examined the role of abdominal adiposity (i.e., waist-to-hip ratio, WHR) as a potential mediator of the relationship between the MD and CRC in the Italian centres of the European Prospective Investigation into Cancer and Nutrition. We evaluated the effect of the Italian Mediterranean Index (IMI) on WHR and of WHR on CRC risk. We then estimated the natural indirect effect (NIE, mediated by WHR) and the pure direct effect (PDE, unmediated) of IMI on CRC risk using mediation analyses, considering age, sex, education, physical activity, smoking and EPIC centre as confounders. Increased IMI was associated with significantly decreased odds of high WHR (odds ratio [OR] for an IMI of 6-11 vs. 0-1: 0.88, 95% confidence interval [CI]: 0.81-0.97). There was a positive relationship between WHR and CRC (hazard ratio [HR] for high vs. low WHR: 1.34, 95%CI: 1.09-1.66). The total effect of IMI was protective on CRC risk and was mainly explained by the PDE (HR for an IMI of 6-11 vs. 0-1: 0.51, 95%CI: 0.31-0.83), whereas the NIE was 1.00 (95%CI: 0.94-1.10). In this Mediterranean cohort, the protective effect of the MD on the development of CRC was not mediated by abdominal adiposity. Since this is the first study to investigate the mediating effect of abdominal obesity, other studies are needed to replicate this result. © 2017 UICC.

  7. HLA-A11-mediated protection from NK cell-mediated lysis: role of HLA-A11-presented peptides.

    PubMed

    Gavioli, R; Zhang, Q J; Masucci, M G

    1996-08-01

    The capacity of MHC class I to protect target cells from NK is well established, but the mechanism by which these molecules influence NK recognition and the physical properties associated with this function remain poorly defined. We have examined this issue using as a model the HLA-A11 allele. HLA-A11 expression correlated with reduced susceptibility to NK and interferon-activated cytotoxicity in transfected sublines of the A11-defective Burkitt's lymphoma WW2-BL and the HLA class I A,B-null C1R cell line. Protection was also achieved by transfection of HLA-A11 in the peptide processing mutant T2 cells line (T2/A11), despite a very low expression of the transfected product at the cell surface. Induction of surface HLA-A11 by culture of T2/A11 cells at 26 degrees C or in the presence of beta 2m did not affect lysis, whereas NK sensitivity was restored by culture in the presence of HLA-All-binding synthetic peptides derived from viral or cellular proteins. Acid treatment rendered T2/A11 and C1R/A11 cells sensitive to lysis, but protection was restored after preincubation with peptide preparations derived from surface stripping of T2/A11 cells. Similar peptide preparations from T2 cells had no effect. The results suggest that NK protection is mediated by HLA-A11 molecules carrying a particular set of peptides that are translocated to the site of MHC class I assembly in the ER in a TAP-independent fashion.

  8. Adolescent pain catastrophizing mediates the relationship between protective parental responses to pain and disability over time.

    PubMed

    Welkom, Josie S; Hwang, Wei-Ting; Guite, Jessica W

    2013-06-01

    Examine whether the relation between protective parenting responses to pain and functional disability is mediated by pain catastrophizing in adolescents with chronic musculoskeletal pain and their parents over time. Adolescents aged 11-18 years and their parents reported on parental protective responses to pain (PPRP), pain catastrophizing scale (PCS), and Functional Disability Inventory (FDI) before Time 1 (T1) and 2 months after Time 2 (T2) an initial interdisciplinary pain clinic evaluation. PCS was a significant mediator of the PPRP-FDI relationship at T1 and T2 for the adolescents and T2 for their parents. A decrease in PPRP over time was associated with T2 PCS, which in turn was associated with T2 FDI for adolescents and their parents. Parental protectiveness is associated with disability indirectly through pain catastrophizing at the initial visit and follow-up. Decreases in parent protectiveness, potentially initiated through the initial evaluation, were related to lower levels of disability at follow-up through pain catastrophizing.

  9. Apical Organelle Secretion by Toxoplasma Controls Innate and Adaptive Immunity and Mediates Long-Term Protection.

    PubMed

    Sloves, Pierre-Julien; Mouveaux, Thomas; Ait-Yahia, Saliha; Vorng, Han; Everaere, Laetitia; Sangare, Lamba Omar; Tsicopoulos, Anne; Tomavo, Stanislas

    2015-11-01

    Apicomplexan parasites have unique apical rhoptry and microneme secretory organelles that are crucial for host infection, although their role in protection against Toxoplasma gondii infection is not thoroughly understood. Here, we report a novel function of the endolysosomal T. gondii sortilin-like receptor (TgSORTLR), which mediates trafficking to functional apical organelles and their subsequent secretion of virulence factors that are critical to the induction of sterile immunity against parasite reinfection. We further demonstrate that the T. gondii armadillo repeats-only protein (TgARO) mutant, which is deficient only in apical secretion of rhoptries, is also critical in mounting protective immunity. The lack of TgSORTLR and TgARO proteins completely inhibited T-helper 1-dependent adaptive immunity and compromised the function of natural killer T-cell-mediated innate immunity. Our findings reveal an essential role for apical secretion in promoting sterile protection against T. gondii and provide strong evidence for rhoptry-regulated discharge of antigens as a key effector for inducing protective immunity.

  10. Prominent role of exopeptidase DPP III in estrogen-mediated protection against hyperoxia in vivo

    PubMed Central

    Sobočanec, Sandra; Filić, Vedrana; Matovina, Mihaela; Majhen, Dragomira; Šafranko, Željka Mačak; Hadžija, Marijana Popović; Krsnik, Željka; Kurilj, Andrea Gudan; Šarić, Ana; Abramić, Marija; Balog, Tihomir

    2016-01-01

    A number of age-related diseases have a low incidence in females, which is attributed to a protective effect of sex hormones. For instance, the female sex hormone estrogen (E2) has a well established cytoprotective effect against oxidative stress, which strongly contributes to ageing. However, the mechanism by which E2 exerts its protective activity remains elusive. In this study we address the question whether the E2-induced protective effect against hyperoxia is mediated by the Nrf-2/Keap-1 signaling pathway. In particular, we investigate the E2-induced expression and cellular distribution of DPP III monozinc exopeptidase, a member of the Nrf-2/Keap-1 pathway, upon hyperoxia treatment. We find that DPP III accumulates in the nucleus in response to hyperoxia. Further, we show that combined induction of hyperoxia and E2 administration have an additive effect on the nuclear accumulation of DPP III. The level of nuclear accumulation of DPP III is comparable to nuclear accumulation of Nrf-2 in healthy female mice exposed to hyperoxia. In ovariectomized females exposed to hyperoxia, supplementation of E2 induced upregulation of DPP III, Ho-1, Sirt-1 and downregulation of Ppar-γ. While other cytoprotective mechanisms cannot be excluded, these findings demonstrate a prominent role of DPP III, along with Sirt-1, in the E2-mediated protection against hyperoxia. PMID:26774752

  11. Host Nonresponsiveness Does not Interfere With Vaccine-Mediated Protection Against Gastric Helicobacter Infection.

    PubMed

    Harbour, Stacey N; Mitchell, Hazel M; Sutton, Philip

    2015-06-01

    Helicobacter pylori pathogenesis results from the inflammation induced by chronic infection. CBA mice are nonresponsive to gastric Helicobacter infection, providing a useful model for examining host regulation of Helicobacter-induced gastritis. We examined whether gastric Helicobacter nonresponsiveness impacts upon vaccine efficacy and whether immune-mediated protection could occur in the absence of inflammation. Mice were vaccinated prior to challenge with Helicobacter felis or H. pylori. Gastritis and H. felis colonization was evaluated histologically. H. pylori colonization was quantified by colony-forming assay. Immunizations protected CBA mice against challenge with either H. felis or H. pylori. Protection against H. felis was marked by a loss of nonresponsiveness and development of an atrophic gastritis with mucus metaplasia. However, vaccine-induced protection against H. pylori was only associated with cell infiltration into the gastric mucosa. Nonresponsiveness to gastric Helicobacter infection did not interfere with vaccination-induced protection. Vaccine-induced protective immunity against H. pylori was linked with the induction of cellular infiltration, but importantly not atrophic gastritis. © 2015 John Wiley & Sons Ltd.

  12. Role of the hypothalamus in mediating protective effects of dietary restriction during aging

    PubMed Central

    Dacks, Penny A.; Moreno, Cesar L.; Kim, Esther S.; Marcellino, Bridget K.; Mobbs, Charles V.

    2013-01-01

    Dietary restriction (DR) can extend lifespan and reduce disease burden across a wide range of animals and yeast but the mechanisms mediating these remarkably protective effects remain to be elucidated despite extensive efforts. Although it has generally been assumed that protective effects of DR are cell-autonomous, there is considerable evidence that many whole-body responses to nutritional state, including DR, are regulated by nutrient-sensing neurons. In this review, we explore the hypothesis that nutrient sensing neurons in the ventromedial hypothalamus hierarchically regulate the protective responses of dietary restriction. We describe multiple peripheral responses that are hierarchically regulated by the hypothalamus and we present evidence for non-cell autonomous signaling of dietary restriction gathered from a diverse range of models including invertebrates, mammalian cell culture, and rodent studies. PMID:23262258

  13. Identification of the heart as the critical site of adenosine mediated embryo protection

    PubMed Central

    2010-01-01

    Background Our understanding of the mechanisms that protect the developing embryo from intrauterine stress is limited. Recently, adenosine has been demonstrated to play a critical role in protecting the embryo against hypoxia via adenosine A1 receptors (A1ARs), which are expressed in the heart, nervous system, and other sites during development. However, the sites of A1AR action that mediate embryo protection are not known. To determine if the heart is a key site of adenosine-mediated embryo protection, A1ARs were selectively deleted in the embryonic heart using a Cre-LoxP system in which the alpha-myosin heavy chain promoter drives Cre-recombinase expression and excision of the A1AR gene from cardiomyocytes. Results With increasing exposure of maternal hypoxia (10% O2) from 48-96 hours beginning at embryonic day (E) 8.5, embryo viability decreased in the cardiac-A1AR deleted embryos. 48 hours of hypoxia reduced embryonic viability by 49% in embryos exposed from E10.5-12.5 but no effect on viability was observed in younger embryos exposed to hypoxia from E8.5-10.5. After 72 hours of hypoxia, 57.8% of the cardiac-A1AR deleted embryos were either dead or re-absorbed compared to 13.7% of control littermates and after 96 hours 81.6% of cardiac-A1AR deleted embryos were dead or re-absorbed. After 72 hours of hypoxia, cardiac size was reduced significantly more in the cardiac-A1AR deleted hearts compared to controls. Gene expression analysis revealed clusters of genes that are regulated by both hypoxia and A1AR expression. Conclusions These data identify the embryonic heart as the critical site where adenosine acts to protect the embryo against hypoxia. As such these studies identify a previously unrecognized mechanism of embryo protection. PMID:20509906

  14. Asef mediates HGF protective effects against LPS-induced lung injury and endothelial barrier dysfunction.

    PubMed

    Meng, Fanyong; Meliton, Angelo; Moldobaeva, Nurgul; Mutlu, Gokhan; Kawasaki, Yoshihiro; Akiyama, Tetsu; Birukova, Anna A

    2015-03-01

    Increased vascular endothelial permeability and inflammation are major pathological mechanisms of pulmonary edema and its life-threatening complication, the acute respiratory distress syndrome (ARDS). We have previously described potent protective effects of hepatocyte growth factor (HGF) against thrombin-induced hyperpermeability and identified the Rac pathway as a key mechanism of HGF-mediated endothelial barrier protection. However, anti-inflammatory effects of HGF are less understood. This study examined effects of HGF on the pulmonary endothelial cell (EC) inflammatory activation and barrier dysfunction caused by the gram-negative bacterial pathogen lipopolysaccharide (LPS). We tested involvement of the novel Rac-specific guanine nucleotide exchange factor Asef in the HGF anti-inflammatory effects. HGF protected the pulmonary EC monolayer against LPS-induced hyperpermeability, disruption of monolayer integrity, activation of NF-kB signaling, expression of adhesion molecules intercellular adhesion molecule-1 and vascular cell adhesion molecule-1, and production of IL-8. These effects were critically dependent on Asef. Small-interfering RNA-induced downregulation of Asef attenuated HGF protective effects against LPS-induced EC barrier failure. Protective effects of HGF against LPS-induced lung inflammation and vascular leak were also diminished in Asef knockout mice. Taken together, these results demonstrate potent anti-inflammatory effects by HGF and delineate a key role of Asef in the mediation of the HGF barrier protective and anti-inflammatory effects. Modulation of Asef activity may have important implications in therapeutic strategies aimed at the treatment of sepsis and acute lung injury/ARDS-induced gram-negative bacterial pathogens.

  15. Finite element analysis for the evaluation of protective functions of helmets against ballistic impact.

    PubMed

    Lee, H P; Gong, S W

    2010-10-01

    The ballistic impact of a human head model protected by a Personnel Armor System Ground Troops Kevlar® helmet is analysed using the finite element method. The emphasis is to examine the effect of the interior cushioning system as a shock absorber in mitigating ballistic impact to the head. The simulations of the frontal and side impacts of the full metal jacket (FMJ) and fragment-simulating projectile (FSP) were carried out using LS-DYNA. It was found that the Kevlar® helmet with its interior nylon and leather strap was able to defeat both the FMJ and FSP without the projectiles penetrating the helmet. However, the head injuries caused by the FMJ impact can be fatal due to the high stiffness of the interior strap. The bulge section at the side of the Kevlar® helmet had more room for deformation that resulted in less serious head injuries.

  16. Molecular Mechanisms Responsible for Neuron-Derived Conditioned Medium (NCM)-Mediated Protection of Ischemic Brain

    PubMed Central

    Lin, Chi-Hsin; Wang, Chen-Hsuan; Hsu, Shih-Lan; Liao, Li-Ya; Lin, Ting-An; Hsueh, Chi-Mei

    2016-01-01

    The protective value of neuron-derived conditioned medium (NCM) in cerebral ischemia and the underlying mechanism(s) responsible for NCM-mediated brain protection against cerebral ischemia were investigated in the study. NCM was first collected from the neuronal culture growing under the in vitro ischemic condition (glucose-, oxygen- and serum-deprivation or GOSD) for 2, 4 or 6 h. Through the focal cerebral ischemia (bilateral CCAO/unilateral MCAO) animal model, we discovered that ischemia/reperfusion (I/R)-induced brain infarction was significantly reduced by NCM, given directly into the cistern magna at the end of 90 min of CCAO/MCAO. Immunoblocking and chemical blocking strategies were applied in the in vitro ischemic studies to show that NCM supplement could protect microglia, astrocytes and neurons from GOSD-induced cell death, in a growth factor (TGFβ1, NT-3 and GDNF) and p-ERK dependent manner. Brain injection with TGFβ1, NT3, GDNF and ERK agonist (DADS) alone or in combination, therefore also significantly decreased the infarct volume of ischemic brain. Moreover, NCM could inhibit ROS but stimulate IL-1β release from GOSD-treated microglia and limit the infiltration of IL-β-positive microglia into the core area of ischemic brain, revealing the anti-oxidant and anti-inflammatory activities of NCM. In overall, NCM-mediated brain protection against cerebral ischemia has been demonstrated for the first time in S.D. rats, due to its anti-apoptotic, anti-oxidant and potentially anti-glutamate activities (NCM-induced IL-1β can inhibit the glutamate-mediated neurotoxicity) and restriction upon the infiltration of inflammatory microglia into the core area of ischemic brain. The therapeutic potentials of NCM, TGFβ1, GDNF, NT-3 and DADS in the control of cerebral ischemia in human therefore have been suggested and require further investigation. PMID:26745377

  17. Molecular Mechanisms Responsible for Neuron-Derived Conditioned Medium (NCM)-Mediated Protection of Ischemic Brain.

    PubMed

    Lin, Chi-Hsin; Wang, Chen-Hsuan; Hsu, Shih-Lan; Liao, Li-Ya; Lin, Ting-An; Hsueh, Chi-Mei

    2016-01-01

    The protective value of neuron-derived conditioned medium (NCM) in cerebral ischemia and the underlying mechanism(s) responsible for NCM-mediated brain protection against cerebral ischemia were investigated in the study. NCM was first collected from the neuronal culture growing under the in vitro ischemic condition (glucose-, oxygen- and serum-deprivation or GOSD) for 2, 4 or 6 h. Through the focal cerebral ischemia (bilateral CCAO/unilateral MCAO) animal model, we discovered that ischemia/reperfusion (I/R)-induced brain infarction was significantly reduced by NCM, given directly into the cistern magna at the end of 90 min of CCAO/MCAO. Immunoblocking and chemical blocking strategies were applied in the in vitro ischemic studies to show that NCM supplement could protect microglia, astrocytes and neurons from GOSD-induced cell death, in a growth factor (TGFβ1, NT-3 and GDNF) and p-ERK dependent manner. Brain injection with TGFβ1, NT3, GDNF and ERK agonist (DADS) alone or in combination, therefore also significantly decreased the infarct volume of ischemic brain. Moreover, NCM could inhibit ROS but stimulate IL-1β release from GOSD-treated microglia and limit the infiltration of IL-β-positive microglia into the core area of ischemic brain, revealing the anti-oxidant and anti-inflammatory activities of NCM. In overall, NCM-mediated brain protection against cerebral ischemia has been demonstrated for the first time in S.D. rats, due to its anti-apoptotic, anti-oxidant and potentially anti-glutamate activities (NCM-induced IL-1β can inhibit the glutamate-mediated neurotoxicity) and restriction upon the infiltration of inflammatory microglia into the core area of ischemic brain. The therapeutic potentials of NCM, TGFβ1, GDNF, NT-3 and DADS in the control of cerebral ischemia in human therefore have been suggested and require further investigation.

  18. Repetitive Element-Mediated Recombination as a Mechanism for New Gene Origination in Drosophila

    PubMed Central

    Li, Xin; Ding, Yun; Zhou, Qi; Chen, Ying; Zhang, Yue; Zhao, Ruoping; Brunet, Frédéric; Peng, Lixin; Long, Manyuan; Wang, Wen

    2008-01-01

    Previous studies of repetitive elements (REs) have implicated a mechanistic role in generating new chimerical genes. Such examples are consistent with the classic model for exon shuffling, which relies on non-homologous recombination. However, recent data for chromosomal aberrations in model organisms suggest that ectopic homology-dependent recombination may also be important. Lack of a dataset comprising experimentally verified young duplicates has hampered an effective examination of these models as well as an investigation of sequence features that mediate the rearrangements. Here we use ∼7,000 cDNA probes (∼112,000 primary images) to screen eight species within the Drosophila melanogaster subgroup and identify 17 duplicates that were generated through ectopic recombination within the last 12 mys. Most of these are functional and have evolved divergent expression patterns and novel chimeric structures. Examination of their flanking sequences revealed an excess of repetitive sequences, with the majority belonging to the transposable element DNAREP1 family, associated with the new genes. Our dataset strongly suggests an important role for REs in the generation of chimeric genes within these species. PMID:18208328

  19. Cytoplasmic polyadenylation elements mediate masking and unmasking of cyclin B1 mRNA.

    PubMed Central

    de Moor, C H; Richter, J D

    1999-01-01

    During oocyte maturation, cyclin B1 mRNA is translationally activated by cytoplasmic polyadenylation. This process is dependent on cytoplasmic polyadenylation elements (CPEs) in the 3' untranslated region (UTR) of the mRNA. To determine whether a titratable factor might be involved in the initial translational repression (masking) of this mRNA, high levels of cyclin B1 3' UTR were injected into oocytes. While this treatment had no effect on the poly(A) tail length of endogenous cyclin B1 mRNA, it induced cyclin B1 synthesis. A mutational analysis revealed that the most efficient unmasking element in the cyclin 3' UTR was the CPE. However, other U-rich sequences that resemble the CPE in structure, but which do not bind the CPE-binding polyadenylation factor CPEB, failed to induce unmasking. When fused to the chloramphenical acetyl transferase (CAT) coding region, the cyclin B1 3' UTR inhibited CAT translation in injected oocytes. In addition, a synthetic 3' UTR containing multiple copies of the CPE also inhibited translation, and did so in a dose-dependent manner. Furthermore, efficient CPE-mediated masking required cap-dependent translation. During the normal course of progesterone-induced maturation, cytoplasmic polyadenylation was necessary for mRNA unmasking. A model to explain how cyclin B1 mRNA masking and unmasking could be regulated by the CPE is presented. PMID:10205182

  20. Protective effect of magnesium acetyltaurate against NMDA-induced retinal damage involves restoration of minerals and trace elements homeostasis.

    PubMed

    Jafri, Azliana Jusnida Ahmad; Arfuzir, Natasha Najwa Nor; Lambuk, Lidawani; Iezhitsa, Igor; Agarwal, Renu; Agarwal, Puneet; Razali, Norhafiza; Krasilnikova, Anna; Kharitonova, Maria; Demidov, Vasily; Serebryansky, Evgeny; Skalny, Anatoly; Spasov, Alexander; Yusof, Ahmad Pauzi Md; Ismail, Nafeeza Mohd

    2017-01-01

    Glutamate-mediated excitotoxicity involving N-methyl-d-aspartate (NMDA) receptors has been recognized as a final common outcome in pathological conditions involving death of retinal ganglion cells (RGCs). Overstimulation of NMDA receptors results in influx of calcium (Ca) and sodium (Na) ions and efflux of potassium (K). NMDA receptors are blocked by magnesium (Mg). Such changes due to NMDA overstimulation are also associated with not only the altered levels of minerals but also that of trace elements and redox status. Both the decreased and elevated levels of trace elements such as iron (Fe), zinc (Zn), copper (Cu) affect NMDA receptor excitability and redox status. Manganese (Mn), and selenium (Se) are also part of antioxidant defense mechanisms in retina. Additionally endogenous substances such as taurine also affect NMDA receptor activity and retinal redox status. Therefore, the aim of this study was to evaluate the effect of Mg acetyltaurate (MgAT) on the retinal mineral and trace element concentration, oxidative stress, retinal morphology and retinal cell apoptosis in rats after-NMDA exposure. One group of Sprague Dawley rats received intravitreal injection of vehicle while 4 other groups similarly received NMDA (160nmolL(-1)). Among the NMDA injected groups, 3 groups also received MgAT (320nmolL(-1)) as pre-treatment, co-treatment or post-treatment. Seven days after intravitreal injection, rats were sacrificed, eyes were enucleated and retinae were isolated for estimation of mineral (Ca, Na, K, Mg) and trace element (Mn, Cu, Fe, Se, Zn) concentration using Inductively Coupled Plasma (DRC ICP-MS) techniques (NexION 300D), retinal oxidative stress using Elisa, retinal morphology using H&E staining and retinal cell apoptosis using terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL). Intravitreal NMDA injection resulted in increased concentration of Ca (4.6 times, p<0.0001), Mg (1.5 times, p<0.01), Na (3 times, p<0.0001) and K (2.3 times, p<0

  1. Transposable Element-Mediated Balancing Selection at Hsp90 Underlies Embryo Developmental Variation.

    PubMed

    Chen, Bing; Zhang, Bo; Xu, Lingling; Li, Qing; Jiang, Feng; Yang, Pengcheng; Xu, Yanan; Kang, Le

    2017-05-01

    Understanding the roles of transposable elements (TEs) in the evolution of genome and adaptation is a long-sought goal. Here, we present a new model of TE co-option, in which a TE is harnessed by an essential gene and confers local adaptation through heterozygote advantage. We characterized a human Alu-like TE family, the Lm1 elements, in the genome of the migratory locust Locusta migratoria that harbors 0.7 million copies of the elements. Scanning Lm1 insertions in the natural locust populations revealed the widespread high polymorphism of Lm1. An Lm1 was recruited into the coding region of Heat-shock protein 90 (Hsp90), an important molecular chaperone for diverse signal transduction and developmental pathways. Only heterozygotes of the allele are present in natural populations. Allele frequency increases with decreased latitudes in east coastal China, even increasing up to 76% in southern populations. Regions flanking the Lm1 insertion display clear signatures of a selective sweep linked to Lm1. The Lm1-mediated Hsp90 mutation is consequential for the embryonic development of locust. Heterozygous embryos develop faster than the wild type, particularly when cued by long-day parental photoperiod. The heterozygotes also present a reduced within-population variation in embryonic development, i.e., high developmental synchrony of embryos. The naturally occurring Hsp90 mutation could facilitate multivoltinism and developmental synchronization of the locust in southern tropical region. These results revealed a genetic mechanism behind microevolutionary changes in which balancing selection may have acted to maintain the heterozygote advantage through TE co-option in essential genes. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Gross Deletions Involving IGHM, BTK, or Artemis: A Model for Genomic Lesions Mediated by Transposable Elements

    PubMed Central

    van Zelm, Menno C.; Geertsema, Corinne; Nieuwenhuis, Nicole; de Ridder, Dick; Conley, Mary Ellen; Schiff, Claudine; Tezcan, Ilhan; Bernatowska, Ewa; Hartwig, Nico G.; Sanders, Elisabeth A.M.; Litzman, Jiri; Kondratenko, Irina; van Dongen, Jacques J.M.; van der Burg, Mirjam

    2008-01-01

    Most genetic disruptions underlying human disease are microlesions, whereas gross lesions are rare with gross deletions being most frequently found (6%). Similar observations have been made in primary immunodeficiency genes, such as BTK, but for unknown reasons the IGHM and DCLRE1C (Artemis) gene defects frequently represent gross deletions (∼60%). We characterized the gross deletion breakpoints in IGHM-, BTK-, and Artemis-deficient patients. The IGHM deletion breakpoints did not show involvement of recombination signal sequences or immunoglobulin switch regions. Instead, five IGHM, eight BTK, and five unique Artemis breakpoints were located in or near sequences derived from transposable elements (TE). The breakpoints of four out of five disrupted Artemis alleles were located in highly homologous regions, similar to Ig subclass deficiencies and Vh deletion polymorphisms. Nevertheless, these observations suggest a role for TEs in mediating gross deletions. The identified gross deletion breakpoints were mostly located in TE subclasses that were specifically overrepresented in the involved gene as compared to the average in the human genome. This concerned both long (LINE1) and short (Alu, MIR) interspersed elements, as well as LTR retrotransposons (ERV). Furthermore, a high total TE content (>40%) was associated with an increased frequency of gross deletions. Both findings were further investigated and confirmed in a total set of 20 genes disrupted in human disease. Thus, to our knowledge for the first time, we provide evidence that a high TE content, irrespective of the type of element, results in the increased incidence of gross deletions as gene disruption underlying human disease. PMID:18252213

  3. c-FLIP Protects Eosinophils from TNF-α-Mediated Cell Death In Vivo

    PubMed Central

    Gordy, Claire; Liang, Jie; Pua, Heather; He, You-Wen

    2014-01-01

    Understanding the signals that regulate eosinophil survival and death is critical to developing new treatments for asthma, atopy, and gastrointestinal disease. Previous studies suggest that TNF-α stimulation protects eosinophils from apoptosis, and this TNF-α-mediated protection is mediated by the upregulation of an unknown protein by NF-κB. Here, we show for the first time that eosinophils express the caspase 8-inhibitory protein c-FLIP, and c-FLIP expression is upregulated upon TNF-α stimulation. Considering that c-FLIP expression is regulated by NF-κB, we hypothesized that c-FLIP might serve as the “molecular switch” that converts TNFRI activation to a pro-survival signal in eosinophils. Indeed, we found that one c-FLIP isoform, c-FLIPL, is required for mouse eosinophil survival in the presence of TNF-α both in vitro and in vivo. Importantly, our results suggest c-FLIP as a potential therapeutic target for the treatment of eosinophil-mediated disease. PMID:25333625

  4. Regulatory T cells participate in CD39-mediated protection from renal injury.

    PubMed

    Wang, Yuan Min; McRae, Jennifer L; Robson, Simon C; Cowan, Peter J; Zhang, Geoff Yu; Hu, Min; Polhill, Tania; Wang, Yiping; Zheng, Guoping; Wang, Ya; Lee, Vincent W S; Unwin, Robert J; Harris, David C H; Dwyer, Karen M; Alexander, Stephen I

    2012-09-01

    CD39 is an ecto-enzyme that degrades extracellular nucleotides, such as ATP, and is highly expressed on by the vasculature and circulating cells including Foxp3+ regulatory T (Treg) cells. To study the role of purinergic regulation in renal disease, we used the adriamycin nephropathy (AN) mouse model of chronic renal injury, using human CD39-transgenic (hCD39Tg) and wild-type (WT) BALB/c mice. Effects of CD39 expression by Treg cells were assessed in AN by adoptive transfer of CD4(+) CD25(+) and CD4(+) CD25(-) T cells isolated from hCD39Tg and WT mice. hCD39Tg mice were protected from renal injury in AN with decreased urinary protein and serum creatinine, and significantly less renal injury compared with WT mice. While WT CD25(+) and hCD39Tg CD25(-) T cells conferred some protection against AN, hCD39Tg CD25(+) Treg cells offered greater protection. In vitro studies showed direct pro-apoptotic effects of ATP on renal tubular cells. In conclusion, hCD39 expressed by circulating leukocytes and intrinsic renal cells limits innate AN injury. Specifically, CD39 expression by Treg cells contributes to its protective role in renal injury. These findings suggest that extracellular nucleotides mediate AN kidney injury and that CD39, expressed by Treg cells and other cells, is protective in this model.

  5. Role of Fc in Antibody-Mediated Protection from Ricin Toxin

    PubMed Central

    Pincus, Seth. H.; Das, Anushka; Song, Kejing; Maresh, Grace A.; Corti, Miriam; Berry, Jody

    2014-01-01

    We have studied the role of the antibody (Ab) Fc region in mediating protection from ricin toxicity. We compared the in vitro and in vivo effects of intact Ig and of Fab fragments derived from two different neutralizing Ab preparations, one monoclonal, the other polyclonal. Consistent results were obtained from each, showing little difference between Ig and Fab in terms of antigen binding and in vitro neutralization, but with relatively large differences in protection of animals. We also studied whether importing Ab into the cell by Fc receptors enhanced the intracellular neutralization of ricin toxin. We found that the imported Ab was found in the ER and Golgi, a compartment traversed by ricin, as it traffics through the cell, but intracellular Ab did not contribute to the neutralization of ricin. These results indicate that the Fc region of antibody is important for in vivo protection, although the mechanism of enhanced protection by intact Ig does not appear to operate at the single cell level. When using xenogeneic antibodies, the diminished immunogenicity of Fab/F(ab’)2 preparations should be balanced against possible loss of protective efficacy. PMID:24811206

  6. Role of Fc in antibody-mediated protection from ricin toxin.

    PubMed

    Pincus, Seth H; Das, Anushka; Song, Kejing; Maresh, Grace A; Corti, Miriam; Berry, Jody

    2014-05-07

    We have studied the role of the antibody (Ab) Fc region in mediating protection from ricin toxicity. We compared the in vitro and in vivo effects of intact Ig and of Fab fragments derived from two different neutralizing Ab preparations, one monoclonal, the other polyclonal. Consistent results were obtained from each, showing little difference between Ig and Fab in terms of antigen binding and in vitro neutralization, but with relatively large differences in protection of animals. We also studied whether importing Ab into the cell by Fc receptors enhanced the intracellular neutralization of ricin toxin. We found that the imported Ab was found in the ER and Golgi, a compartment traversed by ricin, as it traffics through the cell, but intracellular Ab did not contribute to the neutralization of ricin. These results indicate that the Fc region of antibody is important for in vivo protection, although the mechanism of enhanced protection by intact Ig does not appear to operate at the single cell level. When using xenogeneic antibodies, the diminished immunogenicity of Fab/F(ab')2 preparations should be balanced against possible loss of protective efficacy.

  7. IL-11 Is Required for A1 Adenosine Receptor–Mediated Protection against Ischemic AKI

    PubMed Central

    Kim, Joo Yun; Kim, Mihwa; Ham, Ahrom; Brown, Kevin M.; Greene, Robert W.; D’Agati, Vivette D.

    2013-01-01

    A1 adenosine receptor activation ameliorates ischemic AKI through the induction of renal proximal tubular sphingosine kinase-1. However, systemic adverse effects may limit A1 adenosine receptor–based therapy for ischemic AKI, indicating a need to identify alternative therapeutic targets within this pathway. Here, we evaluated the function of renal proximal tubular IL-11, a clinically approved hematopoietic cytokine, in A1 adenosine receptor–mediated induction of sphingosine kinase-1 and renal protection. Treatment of human proximal tubule epithelial (HK-2) cells with a selective A1 adenosine receptor agonist, chloro-N(6)-cyclopentyladenosine (CCPA), induced the expression of IL-11 mRNA and protein in an extracellular signal–regulated kinase–dependent manner, and administration of CCPA in mice induced renal synthesis of IL-11. Pretreatment with CCPA protected against renal ischemia-reperfusion injury in wild-type mice, but not in IL-11 receptor–deficient mice. Administration of an IL-11–neutralizing antibody abolished the renal protection provided by CCPA. Similarly, CCPA did not induce renal IL-11 expression or protect against renal ischemia-reperfusion injury in mice lacking the renal proximal tubular A1 adenosine receptor. Finally, treatment with CCPA induced sphingosine kinase-1 in HK-2 cells and wild-type mice, but not in IL-11 receptor–deficient or renal proximal tubule A1 adenosine receptor–deficient mice. Taken together, these results suggest that induction of renal proximal tubule IL-11 is a critical intermediary in A1 adenosine receptor–mediated renal protection that warrants investigation as a novel therapeutic target for the treatment of ischemic AKI. PMID:23813214

  8. Troxerutin protects the mouse liver against oxidative stress-mediated injury induced by D-galactose.

    PubMed

    Zhang, Zi-feng; Fan, Shao-hua; Zheng, Yuan-lin; Lu, Jun; Wu, Dong-mei; Shan, Qun; Hu, Bin

    2009-09-09

    Troxerutin, a trihydroxyethylated derivative of rutin, has been well-demonstrated to exert hepatoprotective properties. In the present study, we attempted to explore whether the antioxidant and anti-inflammatory mechanisms were involved in troxerutin-mediated protection from D-gal-induced liver injury. The effects of troxerutin on liver lipid peroxidation, antioxidant enzymatic activities, and the expression of inflammatory mediator were investigated in D-gal-treated mice. The results showed that troxerutin largely attenuated the D-gal-induced TBARS content increase and also markedly renewed the activities of Cu, Zn-SOD, CAT, and GPx in the livers of D-gal-treated mice. Furthermore, troxerutin inhibited the upregulation of the expression of NF-kappaB p65, iNOS, and COX-2 induced by D-gal. D-Gal-induced tissue architecture changes and serum ALT and AST increases were effectively suppressed by troxerutin. In conclusion, these results suggested that troxerutin could protect the mouse liver from D-gal-induced injury by attenuating lipid peroxidation, renewing the activities of antioxidant enzymes and suppressing inflammatory response. This study provided novel insights into the mechanisms of troxerutin in the protection of the liver.

  9. Protective effects of phyllanthus emblica leaf extract on sodium arsenite-mediated adverse effects in mice.

    PubMed

    Sayed, Sadia; Ahsan, Nazmul; Kato, Masashi; Ohgami, Nobutaka; Rashid, Abdur; Akhand, Anwarul Azim

    2015-02-01

    Groundwater contamination of arsenic is the major cause of a serious health hazard in Bangladesh. No specific treatment is yet available to manage the large number of individuals exposed to arsenic. In this study, we evaluated the protective effects of Phyllanthus emblica (Indian gooseberry or Amla) leaf extract (PLE) on arsenic-mediated toxicity in experimental mice. Male Swiss albino mice were divided into three different groups (n=6/group). 'Control' mice received arsenic free water together with normal feed. Mice in the remaining two groups designated 'SA' and 'SA+PLE' were exposed to sodium arsenite (SA, 10 µg/g body weight/day) through drinking water in addition to receiving normal feed and PLE-supplemented feed, respectively. The weight gain of SA-exposed mice was decreased compared with the controls; however, this decrease in body weight gain was prevented when the feed was supplemented with PLE. A secondary effect of arsenic was enlargement of the liver, kidney and spleen of SA-group mice. Deposition of arsenic in those organs was demonstrated by ICP-MS. When PLE was supplemented in the feed the enlargement of the organs was minimized; however, the deposition of arsenic was not significantly reduced. These results indicated that PLE may not block arsenic deposition in tissue directly but rather may play a protective role to reduce arsenic-induced toxicity. Therefore, co-administration of PLE in arsenic-exposed animals might have a future therapeutic application for protecting against arsenic-mediated toxicity.

  10. Next-Generation Insect-Resistant Plants: RNAi-Mediated Crop Protection.

    PubMed

    Zhang, Jiang; Khan, Sher Afzal; Heckel, David G; Bock, Ralph

    2017-09-01

    Plant-mediated RNA interference (RNAi) shows great potential in crop protection. It relies on plants stably expressing double-stranded RNAs (dsRNAs) that target essential genes in pest insects. Practical application of this strategy is challenging because producing sufficient amounts of stable dsRNA in plants has proven to be difficult to achieve with conventional transgenesis. In addition, many insects do not respond to exogenously applied dsRNAs, either degrading them or failing to import them into the cytoplasm. We summarize recent progress in RNAi-mediated insect pest control and discuss factors determining its efficacy. Expressing dsRNA in chloroplasts overcomes many of the difficulties previously encountered. We also highlight remaining challenges and discuss the environmental and biosafety issues involved in the use of this technology in agriculture. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. The protective effect of salicylic acid on lysozyme against riboflavin-mediated photooxidation

    NASA Astrophysics Data System (ADS)

    Li, Kun; Wang, Hongbao; Cheng, Lingli; Zhu, Hui; Wang, Mei; Wang, Shi-Long

    2011-06-01

    As a metabolite of aspirin in vivo, salicylic acid was proved to protect lysozyme from riboflavin-mediated photooxidation in this study. The antioxidative properties of salicylic acid were further studied by using time-resolved laser flash photolysis of 355 nm. It can quench the triplet state of riboflavin via electron transfer from salicylic acid to the triplet state of riboflavin with a reaction constant of 2.25 × 10 9 M -1 s -1. Mechanism of antioxidant activities of salicylic acid on lysozyme oxidation was discussed. Salicylic acid can serve as a potential antioxidant to quench the triplet state of riboflavin and reduce oxidative pressure.

  12. Tumour necrosis factor (TNF alpha) in leishmaniasis. I. TNF alpha mediates host protection against cutaneous leishmaniasis.

    PubMed Central

    Liew, F Y; Parkinson, C; Millott, S; Severn, A; Carrier, M

    1990-01-01

    Genetically resistant CBA mice developed significantly larger lesions to Leishmania major infection when they were injected with rabbit anti-tumour necrosis factor (TNF)-specific antibodies compared to control mice injected with normal rabbit immunoglobulin. BALB/c mice recovered from a previous infection following prophylactic sublethal irradiation also developed exacerbated lesions when treated with the anti-TNF antibody. Injection of TNF into the lesion of infected CBA mice significantly reduced the lesion development. Furthermore, TNF activates macrophages to kill Leishmania in vitro. These data demonstrate that TNF plays an important role in mediating host-protection against cutaneous leishmaniasis. PMID:2335376

  13. Role of Eosinophils and Tumor Necrosis Factor Alpha in Interleukin-25-Mediated Protection from Amebic Colitis

    PubMed Central

    Noor, Zannatun; Watanabe, Koji; Abhyankar, Mayuresh M.; Burgess, Stacey L.; Buonomo, Erica L.

    2017-01-01

    ABSTRACT The parasite Entamoeba histolytica is a cause of diarrhea in infants in low-income countries. Previously, it was shown that tumor necrosis factor alpha (TNF-α) production was associated with increased risk of E. histolytica diarrhea in children. Interleukin-25 (IL-25) is a cytokine that is produced by intestinal epithelial cells that has a role in maintenance of gut barrier function and inhibition of TNF-α production. IL-25 expression was decreased in humans and in the mouse model of amebic colitis. Repletion of IL-25 blocked E. histolytica infection and barrier disruption in mice, increased gut eosinophils, and suppressed colonic TNF-α. Depletion of eosinophils with anti-Siglec-F antibody prevented IL-25-mediated protection. In contrast, depletion of TNF-α resulted in resistance to amebic infection. We concluded that IL-25 provides protection from amebiasis, which is dependent upon intestinal eosinophils and suppression of TNF-α. PMID:28246365

  14. Direct palladium-mediated on-resin disulfide formation from Allocam protected peptides.

    PubMed

    Kondasinghe, Thilini D; Saraha, Hasina Y; Odeesho, Samantha B; Stockdill, Jennifer L

    2017-04-05

    The synthesis of disulfide-containing polypeptides represents a long-standing challenge in peptide chemistry, and broadly applicable methods for the construction of disulfides are in constant demand. Few strategies exist for on-resin formation of disulfides directly from their protected counterparts. We present herein a novel strategy for the on-resin construction of disulfides directly from Allocam-protected cysteines. Our palladium-mediated approach is mild and uses readily available reagents, requiring no special equipment. No reduced peptide intermediates or S-allylated products are observed, and no residual palladium can be detected in the final products. The utility of this method is demonstrated through the synthesis of the C-carboxy analog of oxytocin.

  15. Bacopa monnieri-Induced Protective Autophagy Inhibits Benzo[a]pyrene-Mediated Apoptosis.

    PubMed

    Das, Durgesh Nandini; Naik, Prajna Paramita; Nayak, Aditi; Panda, Prashanta Kumar; Mukhopadhyay, Subhadip; Sinha, Niharika; Bhutia, Sujit K

    2016-11-01

    Benzo[a]pyrene (B[a]P) is capable of inducing oxidative stress and cellular injuries leading to cell death and associates with a significant risk of cancer development. Prevention of B[a]P-induced cellular toxicity with herbal compound through regulation of mitochondrial oxidative stress might protect cell death and have therapeutic benefit to human health. In this study, we demonstrated the cytoprotective role of Bacopa monnieri (BM) against B[a]P-induced apoptosis through autophagy induction. Pretreatment with BM rescued the reduction in cell viability in B[a]P-treated human keratinocytes (HaCaT) cells indicating the cytoprotective potential of BM against B[a]P. Moreover, BM was found to inhibit B[a]P-mediated reactive oxygen species (ROS)-induced apoptosis activation in HaCaT cells. Furthermore, BM was found to preserve mitochondrial membrane potential and inhibited release of cytochrome c in B[a]P-treated HaCaT cells. Bacopa monnieri induced protective autophagy; we knocked down Beclin-1, and data showed that BM was unable to protect from B[a]P-induced mitochondrial ROS-mediated apoptosis in Beclin-1-deficient HaCaT cells. Moreover, we established that B[a]P-induced damaged mitochondria were found to colocalize and degraded within autolysosomes in order to protect HaCaT cells from mitochondrial injury. In conclusion, B[a]P-induced apoptosis was rescued by BM treatment and provided cytoprotection through Beclin-1-dependent autophagy activation. Copyright © 2016 John Wiley & Sons, Ltd.

  16. Toxin-Mediated Paracellular Transport of Antitoxin Antibodies Facilitates Protection against Clostridium difficile Infection

    PubMed Central

    Zhang, Z.; Chen, X.; Hernandez, L. D.; Lipari, P.; Flattery, A.; Chen, S.-C.; Kramer, S.; Polishook, J. D.; Racine, F.; Cape, H.; Kelly, C. P.

    2014-01-01

    The exotoxins TcdA and TcdB are the major virulence factors of Clostridium difficile. Circulating neutralizing antitoxin antibodies are protective in C. difficile infection (CDI), as demonstrated, in part, by the protective effects of actoxumab and bezlotoxumab, which bind to and neutralize TcdA and TcdB, respectively. The question of how systemic IgG antibodies neutralize toxins in the gut lumen remains unresolved, although it has been suggested that the Fc receptor FcRn may be involved in active antibody transport across the gut epithelium. In this study, we demonstrated that genetic ablation of FcRn and excess irrelevant human IgG have no impact on actoxumab-bezlotoxumab-mediated protection in murine and hamster models of CDI, suggesting that Fc-dependent transport of antibodies across the gut wall is not required for efficacy. Tissue distribution studies in hamsters suggest, rather, that the transport of antibodies depends on toxin-induced damage to the gut lining. In an in vitro two-dimensional culture system that mimics the architecture of the intestinal mucosal epithelium, toxins on the apical side of epithelial cell monolayers are neutralized by basolateral antibodies, and antibody transport across the cell layer is dramatically increased upon addition of toxin to the apical side. Similar data were obtained with F(ab′)2 fragments, which lack an Fc domain, consistent with FcRn-independent paracellular, rather than transcellular, transport of antibodies. Kinetic studies show that initial damage caused by apical toxin is required for efficient neutralization by basolateral antibodies. These data may represent a general mechanism of humoral response-mediated protection against enteric pathogens. PMID:25385797

  17. An endothelial TLR4-VEGFR2 pathway mediates lung protection against oxidant-induced injury

    PubMed Central

    Takyar, Seyedtaghi; Zhang, Yi; Haslip, Maria; Jin, Lei; Shan, Peiying; Zhang, Xuchen; Lee, Patty J.

    2015-01-01

    TLR4 deficiency causes hypersusceptibility to oxidant-induced injury. We investigated the role of TLR4 in lung protection, using used bone marrow chimeras; cell-specific transgenic modeling; and lentiviral delivery in vivo to knock down or express TLR4 in various lung compartments; and lung-specific VEGF transgenic mice to investigate the effect of TLR4 on VEGF-mediated protection. C57/BL6 mice were exposed to 100% oxygen in an enclosed chamber and assessed for survival and lung injury. Primary endothelial cells were stimulated with recombinant VEGF and exposed to hyperoxia or hydrogen peroxide. Endothelium-specific expression of human TLR4 (as opposed to its expression in epithelium or immune cells) increased the survival of TLR4-deficent mice in hyperoxia by 24 h and decreased LDH release and lung cell apoptosis after 72 h of exposure by 30%. TLR4 expression was necessary and sufficient for the protective effect of VEGF in the lungs and in primary endothelial cells in culture. TLR4 knockdown inhibited VEGF signaling through VEGF receptor 2 (VEGFR2), Akt, and ERK pathways in lungs and primary endothelial cells and decreased the availability of VEGFR2 at the cell surface. These findings demonstrate a novel mechanism through which TLR4, an innate pattern receptor, interacts with an endothelial survival pathway.—Takyar, S., Zhang, Y., Haslip, M., Jin L., Shan P., Zhang, X., Lee, P. J. An endothelial TLR4-VEGFR2 pathway mediates lung protection against oxidant-induced injury. PMID:26655705

  18. Deciphering Cis-Regulatory Element Mediated Combinatorial Regulation in Rice under Blast Infected Condition

    PubMed Central

    Deb, Arindam; Kundu, Sudip

    2015-01-01

    Combinations of cis-regulatory elements (CREs) present at the promoters facilitate the binding of several transcription factors (TFs), thereby altering the consequent gene expressions. Due to the eminent complexity of the regulatory mechanism, the combinatorics of CRE-mediated transcriptional regulation has been elusive. In this work, we have developed a new methodology that quantifies the co-occurrence tendencies of CREs present in a set of promoter sequences; these co-occurrence scores are filtered in three consecutive steps to test their statistical significance; and the significantly co-occurring CRE pairs are presented as networks. These networks of co-occurring CREs are further transformed to derive higher order of regulatory combinatorics. We have further applied this methodology on the differentially up-regulated gene-sets of rice tissues under fungal (Magnaporthe) infected conditions to demonstrate how it helps to understand the CRE-mediated combinatorial gene regulation. Our analysis includes a wide spectrum of biologically important results. The CRE pairs having a strong tendency to co-occur often exhibit very similar joint distribution patterns at the promoters of rice. We couple the network approach with experimental results of plant gene regulation and defense mechanisms and find evidences of auto and cross regulation among TF families, cross-talk among multiple hormone signaling pathways, similarities and dissimilarities in regulatory combinatorics between different tissues, etc. Our analyses have pointed a highly distributed nature of the combinatorial gene regulation facilitating an efficient alteration in response to fungal attack. All together, our proposed methodology could be an important approach in understanding the combinatorial gene regulation. It can be further applied to unravel the tissue and/or condition specific combinatorial gene regulation in other eukaryotic systems with the availability of annotated genomic sequences and suitable

  19. Wolbachia-Mediated Antiviral Protection in Drosophila Larvae and Adults following Oral Infection

    PubMed Central

    Stevanovic, Aleksej L.; Arnold, Pieter A.

    2015-01-01

    Understanding viral dynamics in arthropods is of great importance when designing models to describe how viral spread can influence arthropod populations. The endosymbiotic bacterium Wolbachia spp., which is present in up to 40% of all insect species, has the ability to alter viral dynamics in both Drosophila spp. and mosquitoes, a feature that in mosquitoes may be utilized to limit spread of important arboviruses. To understand the potential effect of Wolbachia on viral dynamics in nature, it is important to consider the impact of natural routes of virus infection on Wolbachia antiviral effects. Using adult Drosophila strains, we show here that Drosophila-Wolbachia associations that have previously been shown to confer antiviral protection following systemic viral infection also confer protection against virus-induced mortality following oral exposure to Drosophila C virus in adults. Interestingly, a different pattern was observed when the same fly lines were challenged with the virus when still larvae. Analysis of the four Drosophila-Wolbachia associations that were protective in adults indicated that only the w1118-wMelPop association conferred protection in larvae following oral delivery of the virus. Analysis of Wolbachia density using quantitative PCR (qPCR) showed that a high Wolbachia density was congruent with antiviral protection in both adults and larvae. This study indicates that Wolbachia-mediated protection may vary between larval and adult stages of a given Wolbachia-host combination and that the variations in susceptibility by life stage correspond with Wolbachia density. The differences in the outcome of virus infection are likely to influence viral dynamics in Wolbachia-infected insect populations in nature and could also have important implications for the transmission of arboviruses in mosquito populations. PMID:26407882

  20. Wolbachia-mediated antiviral protection in Drosophila larvae and adults following oral infection.

    PubMed

    Stevanovic, Aleksej L; Arnold, Pieter A; Johnson, Karyn N

    2015-12-01

    Understanding viral dynamics in arthropods is of great importance when designing models to describe how viral spread can influence arthropod populations. The endosymbiotic bacterium Wolbachia spp., which is present in up to 40% of all insect species, has the ability to alter viral dynamics in both Drosophila spp. and mosquitoes, a feature that in mosquitoes may be utilized to limit spread of important arboviruses. To understand the potential effect of Wolbachia on viral dynamics in nature, it is important to consider the impact of natural routes of virus infection on Wolbachia antiviral effects. Using adult Drosophila strains, we show here that Drosophila-Wolbachia associations that have previously been shown to confer antiviral protection following systemic viral infection also confer protection against virus-induced mortality following oral exposure to Drosophila C virus in adults. Interestingly, a different pattern was observed when the same fly lines were challenged with the virus when still larvae. Analysis of the four Drosophila-Wolbachia associations that were protective in adults indicated that only the w1118-wMelPop association conferred protection in larvae following oral delivery of the virus. Analysis of Wolbachia density using quantitative PCR (qPCR) showed that a high Wolbachia density was congruent with antiviral protection in both adults and larvae. This study indicates that Wolbachia-mediated protection may vary between larval and adult stages of a given Wolbachia-host combination and that the variations in susceptibility by life stage correspond with Wolbachia density. The differences in the outcome of virus infection are likely to influence viral dynamics in Wolbachia-infected insect populations in nature and could also have important implications for the transmission of arboviruses in mosquito populations. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  1. Selenium-mediated protection in reversing the sensitivity of bacterium to the bactericidal antibiotics.

    PubMed

    Li, Zhonglei; Tan, Jun; Shao, Lei; Dong, Xiaojing; Ye, Richard D; Chen, Daijie

    2017-05-01

    Inducing production of damaging reactive oxygen species (ROS) is an important criterion to distinguish the bactericidal antibiotics from bacteriostatic antibiotics. Selenoenzymes were generally recognized to be a powerful antioxidant capable of scavenging free radicals, protecting the cells from the harmful effects of ROS. Therefore, the present study was carried out to investigate the selenium (Se)-mediated protection in reversing antibiotic sensitivity and the role of selenoenzymes in alleviating the negative effects of oxidative stress. The cellular antioxidant activity of Se-enriched bacteria was analyzed, as well as intracellular ROS production and elimination when Se-enriched bacteria in the presence of various antibiotics. Compared to complete inhibition of the parental strain by bactericidal antibiotics, it only exhibited slight and reversible inhibition of Se-enriched Escherichia coli ATCC25922 and Staphylococcus aureus ATCC25923 at the same conditions, which indicated that intracellular selenium provided substantial protection against antibiotics. ROS generation caused by bactericidal antibiotics was confirmed by fluorescence spectrophotometry using 2', 7'-dichloro- uorescein diacetate (DCFH-DA) as substrate. The time course experiments of pretreatment with selenium showed significant decrease of ROS level at 2h. In summary, the present study provides experimental evidence supporting selenoenzymes has good scavenging effect to ROS and can protect bacteria from oxidative stress injury induced by bactericidal antibiotics. Copyright © 2017 Elsevier GmbH. All rights reserved.

  2. Role of Eosinophils and Tumor Necrosis Factor Alpha in Interleukin-25-Mediated Protection from Amebic Colitis.

    PubMed

    Noor, Zannatun; Watanabe, Koji; Abhyankar, Mayuresh M; Burgess, Stacey L; Buonomo, Erica L; Cowardin, Carrie A; Petri, William A

    2017-02-28

    The parasite Entamoeba histolytica is a cause of diarrhea in infants in low-income countries. Previously, it was shown that tumor necrosis factor alpha (TNF-α) production was associated with increased risk of E. histolytica diarrhea in children. Interleukin-25 (IL-25) is a cytokine that is produced by intestinal epithelial cells that has a role in maintenance of gut barrier function and inhibition of TNF-α production. IL-25 expression was decreased in humans and in the mouse model of amebic colitis. Repletion of IL-25 blocked E. histolytica infection and barrier disruption in mice, increased gut eosinophils, and suppressed colonic TNF-α. Depletion of eosinophils with anti-Siglec-F antibody prevented IL-25-mediated protection. In contrast, depletion of TNF-α resulted in resistance to amebic infection. We concluded that IL-25 provides protection from amebiasis, which is dependent upon intestinal eosinophils and suppression of TNF-α.IMPORTANCE The intestinal epithelial barrier is important for protection from intestinal amebiasis. We discovered that the intestinal epithelial cytokine IL-25 was suppressed during amebic colitis in humans and that protection could be restored in the mouse model by IL-25 administration. IL-25 acted via eosinophils and suppressed TNF-α. This work illustrates a previously unrecognized pathway of innate mucosal immune response. Copyright © 2017 Noor et al.

  3. Mediation Analysis of Decisional Balance, Sun Avoidance, and Sunscreen Use in the Precontemplation and Preparation Stages for Sun Protection

    PubMed Central

    Velicer, Wayne F.; Redding, Colleen

    2015-01-01

    Objective Mediation analyses of sun protection were conducted testing structural equation models using longitudinal data with three waves. An effect was said to be mediated if the standardized path between processes of change, decisional balance, and sun protection outcomes were significant. Design Longitudinal models of sun protection using data from individuals in the precontemplation (N=964) and preparation (N =463) stages who participated of an expert system intervention. Main Outcome Measures Nine processes of change for sun protection, decisional balance constructs of sun protection (pros and cons), sun avoidance behavior, and sunscreen use. Results With the exception of two processes in the preparation stage, processes of change predicted the pros (r= .126 to .614), and the pros predicted the outcomes (r= .181 to .272). Three models with the cons as mediator in the preparation stage, and none in the precontemplation stage, showed a mediated relationship between processes and outcomes. Conclusion In general, mediation analyses found both the process of change-to-pros and pros-to-behavior paths significant for both precontemplation and preparation stages, and for both sun avoidance and sunscreen use outcomes. Findings provide support for the importance of assessing the role of underlying risk cognitions in improving sun protection adherence. PMID:26040293

  4. Mediation analysis of decisional balance, sun avoidance and sunscreen use in the precontemplation and preparation stages for sun protection.

    PubMed

    Santiago-Rivas, Marimer; Velicer, Wayne F; Redding, Colleen

    2015-01-01

    Mediation analyses of sun protection were conducted testing structural equation models using longitudinal data with three waves. An effect was said to be mediated if the standardised path between processes of change, decisional balance and sun protection outcomes was significant. Longitudinal models of sun protection using data from individuals in the precontemplation (N = 964) and preparation (N = 463) stages who participated of an expert system intervention. Nine processes of change for sun protection, decisional balance constructs of sun protection (pros and cons), sun avoidance behaviour and sunscreen use. With the exception of two processes in the preparation stage, processes of change predicted the pros (r = .126-.614), and the pros predicted the outcomes (r = .181-.272). Three models with the cons as mediator in the preparation stage, and none in the precontemplation stage, showed a mediated relationship between processes and outcomes. In general, mediation analyses found both the process of change-to-pros and pros-to-behaviour paths significant for both precontemplation and preparation stages, and for both sun avoidance and sunscreen use outcomes. Findings provide support for the importance of assessing the role of underlying risk cognitions in improving sun protection adherence.

  5. Neonatal Fc receptor expression in dendritic cells mediates protective immunity against colorectal cancer.

    PubMed

    Baker, Kristi; Rath, Timo; Flak, Magdalena B; Arthur, Janelle C; Chen, Zhangguo; Glickman, Jonathan N; Zlobec, Inti; Karamitopoulou, Eva; Stachler, Matthew D; Odze, Robert D; Lencer, Wayne I; Jobin, Christian; Blumberg, Richard S

    2013-12-12

    Cancers arising in mucosal tissues account for a disproportionately large fraction of malignancies. Immunoglobulin G (IgG) and the neonatal Fc receptor for IgG (FcRn) have an important function in the mucosal immune system that we have now shown extends to the induction of CD8(+) T cell-mediated antitumor immunity. We demonstrate that FcRn within dendritic cells (DCs) was critical for homeostatic activation of mucosal CD8(+) T cells that drove protection against the development of colorectal cancers and lung metastases. FcRn-mediated tumor protection was driven by DCs activation of endogenous tumor-reactive CD8(+) T cells via the cross-presentation of IgG complexed antigens (IgG IC), as well as the induction of cytotoxicity-promoting cytokine secretion, particularly interleukin-12, both of which were independently triggered by the FcRn-IgG IC interaction in murine and human DCs. FcRn thus has a primary role within mucosal tissues in activating local immune responses that are critical for priming efficient anti-tumor immunosurveillance.

  6. Protective effect of diphenyl diselenide against peroxynitrite-mediated endothelial cell death: a comparison with ebselen.

    PubMed

    de Bem, Andreza Fabro; Fiuza, Bianca; Calcerrada, Pablo; Brito, Paula M; Peluffo, Gonzalo; Dinis, Teresa C P; Trujillo, Madia; Rocha, João B T; Radi, Rafael; Almeida, Leonor M

    2013-05-31

    Excess production of superoxide (O₂(-)) and nitric oxide (NO) in blood vessel walls may occur early in atherogenesis leading to the formation of peroxynitrite, a strong oxidant and nitrating agent. This study was designed to determine the effect of diphenyl diselenide (PhSe)₂, a synthetic organoselenium compound, in comparison with ebselen, on peroxynitrite-mediated endothelial damage. Experimental results showed that pre-incubation of BAEC (24 h) with low concentrations of (PhSe)₂ (0.5 and 1 μM) protected the cells from peroxynitrite-dependent apoptosis and protein tyrosine nitration. The intracellular levels of GSH were almost completely depleted by peroxynitrite and, although the compounds did not restore its normal levels, (PhSe)₂ per se significantly increased GSH in a concentration-dependent manner. Moreover, (PhSe)₂, which was about two times more active as a GPx mimic than ebselen, induced a significantly higher increase in both cellular GPx expression and activity. Taking into account the kinetics of the reaction between peroxynitrite and (PhSe)₂, our data indicate that (PhSe)₂ protects BAEC against peroxynitrite-mediated cell damage not by a direct reaction, but rather by increasing cellular GPx expression as a consequence of enhanced nuclear translocation of Nrf-2, which together with the increase in intracellular GSH, may work catalytically to reduce peroxynitrite to nitrite. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Organ-Protective Effects of Red Wine Extract, Resveratrol, in Oxidative Stress-Mediated Reperfusion Injury

    PubMed Central

    Liu, Fu-Chao; Tsai, Hsin-I; Yu, Huang-Ping

    2015-01-01

    Resveratrol, a polyphenol extracted from red wine, possesses potential antioxidative and anti-inflammatory effects, including the reduction of free radicals and proinflammatory mediators overproduction, the alteration of the expression of adhesion molecules, and the inhibition of neutrophil function. A growing body of evidence indicates that resveratrol plays an important role in reducing organ damage following ischemia- and hemorrhage-induced reperfusion injury. Such protective phenomenon is reported to be implicated in decreasing the formation and reaction of reactive oxygen species and pro-nflammatory cytokines, as well as the mediation of a variety of intracellular signaling pathways, including the nitric oxide synthase, nicotinamide adenine dinucleotide phosphate oxidase, deacetylase sirtuin 1, mitogen-activated protein kinase, peroxisome proliferator-activated receptor-gamma coactivator 1 alpha, hemeoxygenase-1, and estrogen receptor-related pathways. Reperfusion injury is a complex pathophysiological process that involves multiple factors and pathways. The resveratrol is an effective reactive oxygen species scavenger that exhibits an antioxidative property. In this review, the organ-protective effects of resveratrol in oxidative stress-related reperfusion injury will be discussed. PMID:26161238

  8. Graphite-mediated reduction of 2,4-dinitrotoluene with elemental iron.

    PubMed

    Oh, Seok-Young; Cha, Daniel K; Chiu, Pei C

    2002-05-15

    The mechanism and pathway through which 2,4-dinitrotoluene (DNT) is reduced with elemental iron were investigated through batch experiments performed utilizing the same iron surface area, with high-purity iron powder and Master Builders scrap iron. In addition to different kinetics and adsorption patterns, the distribution of two intermediates, 4-amino-2-nitrotoluene (4A2NT) and 2-amino-4-nitrotoluene (2A4NT), contrasted sharply. This suggests that different mechanisms are involved in DNT reduction with pure iron and scrap iron. We hypothesized that exposed graphite in scrap iron transferred reductants from iron to adsorbed nitroaromatic molecules. This hypothesis was supported by an experiment conducted using two-compartment dialysis cells in which ONT and pure iron powder were separated by a graphite sheet. Results indicate that graphite-mediated, indirect reduction of DNT occurred primarily through reduction of the ortho nitro group to form 2A4NT, whereas DNT reduction at the iron (hydr/oxide) surface occurred via para nitro reduction to give 4A2NT. Based on pH and product analysis, atomic hydrogen probably accounted for most of the reducing equivalents that passed through the graphite, reacting with adsorbed DNT mainly through ortho nitro reduction. In contrast, electron was a minor fraction of the reducing equivalents, reducing DNT mainly through para nitro reduction. The implications of graphite as a reaction site and conductor of electron and atomic hydrogen are discussed with respect to treatment processes involving iron.

  9. Composite response elements mediate hormonal and developmental regulation of milk protein gene expression.

    PubMed

    Rosen, J M; Zahnow, C; Kazansky, A; Raught, B

    1998-01-01

    Our laboratory has been studying the mechanisms by which hormones regulate the expression of differentiated function in the normal mammary gland and how these regulatory mechanisms have deviated in breast cancer. Two rat milk protein genes, encoding beta-casein and whey acidic protein, have been employed as molecular markers of mammary epithelial cell differentiation. Composite response elements containing multiple binding sites for several transcription factors mediate the hormonal and developmental regulation of milk protein gene expression. In the whey protein gene promoters, these include binding sites for nuclear factor (NF)-I, as well as the glucocorticoid receptor (GR) and signal transducers and activators of transcription (Stat5). In the casein promoters, these include binding sites for Stat5, Yin Yang 1 (YY1), GR and the CCAAT/enhancer binding protein (C/EBP). The C/EBP family of DNA binding proteins may play a pivotal role in maintaining the balance between cell proliferation and terminal differentiation in mammary epithelial cells. During normal mammary gland development, expression of LIP (liver-enriched inhibitory protein, a dominant-negative isoform of C/EBP beta) is hormonally regulated and correlates with cell proliferation during pregnancy. LIP can form heterodimers with other C/EBP family members and suppress their transcriptional activity. In contrast, C/EBP alpha is predominantly expressed during lactation following terminal differentiation. Elevated LIP levels have been detected in mouse, rat and human breast tumours of different aetiologies. This provides a mechanism, therefore, to block terminal differentiation and facilitate continued proliferation.

  10. CTCF Binding Elements Mediate Control of V(D)J Recombination

    PubMed Central

    Guo, Chunguang; Yoon, Hye Suk; Franklin, Andrew; Jain, Suvi; Ebert, Anja; Cheng, Hwei-Ling; Hansen, Erica; Despo, Orion; Bossen, Claudia; Vettermann, Christian; Bates, Jamie G.; Richards, Nicholas; Myers, Darienne; Patel, Harin; Gallagher, Michael; Schlissel, Mark S.; Murre, Cornelis; Busslinger, Meinrad; Giallourakis, Cosmas C.; Alt, Frederick W.

    2012-01-01

    Immunoglobulin heavy chain (IgH) variable region exons are assembled from VH, D and JH gene segments in developing B lymphocytes. Within the 2.7 megabase (Mb) mouse IgH locus (IgH), V(D)J recombination is regulated to ensure specific and diverse antibody repertoires. Herein, we report a key IgH V(D)J recombination regulatory region, termed InterGenic Control Region-1 (IGCR1), that lies between the VH and D clusters. Functionally, IGCR1 employs CTCF looping/insulator factor binding elements and, correspondingly, mediates IgH loops containing distant enhancers. IGCR1 promotes normal B cell development and balances antibody repertoires by inhibiting transcription and rearrangement of DH-proximal VHs and promoting rearrangement of distal VHs. IGCR1 maintains ordered and lineage-specific VH(D)JH recombination, respectively, by suppressing VH joining to Ds not joined to JHs and VH to DJH joins in thymocytes. IGCR1 also is required to allow feedback regulation and allelic exclusion of proximal VH to DJH recombination. Our studies elucidate a long-sought IgH V(D)J recombination control region and implicate a new role for the generally expressed CTCF protein. PMID:21909113

  11. Widespread negative response elements mediate direct repression by agonist-liganded glucocorticoid receptor.

    PubMed

    Surjit, Milan; Ganti, Krishna Priya; Mukherji, Atish; Ye, Tao; Hua, Guoqiang; Metzger, Daniel; Li, Mei; Chambon, Pierre

    2011-04-15

    The glucocorticoid (GC) receptor (GR), when liganded to GC, activates transcription through direct binding to simple (+)GRE DNA binding sequences (DBS). GC-induced direct repression via GR binding to complex "negative" GREs (nGREs) has been reported. However, GR-mediated transrepression was generally ascribed to indirect "tethered" interaction with other DNA-bound factors. We report that GC-induces direct transrepression via the binding of GR to simple DBS (IR nGREs) unrelated to (+)GRE. These DBS act on agonist-liganded GR, promoting the assembly of cis-acting GR-SMRT/NCoR repressing complexes. IR nGREs are present in over 1000 mouse/human ortholog genes, which are repressed by GC in vivo. Thus variations in the levels of a single ligand can coordinately turn genes on or off depending in their response element DBS, allowing an additional level of regulation in GR signaling. This mechanism suits GR signaling remarkably well, given that adrenal secretion of GC fluctuates in a circadian and stress-related fashion.

  12. VIP1 response elements mediate mitogen-activated protein kinase 3-induced stress gene expression

    PubMed Central

    Pitzschke, Andrea; Djamei, Armin; Teige, Markus; Hirt, Heribert

    2009-01-01

    The plant pathogen Agrobacterium tumefaciens transforms plant cells by delivering its T-DNA into the plant cell nucleus where it integrates into the plant genome and causes tumor formation. A key role of VirE2-interacting protein 1 (VIP1) in the nuclear import of T-DNA during Agrobacterium-mediated plant transformation has been unravelled and VIP1 was shown to undergo nuclear localization upon phosphorylation by the mitogen-activated protein kinase MPK3. Here, we provide evidence that VIP1 encodes a functional bZIP transcription factor that stimulates stress-dependent gene expression by binding to VIP1 response elements (VREs), a DNA hexamer motif. VREs are overrepresented in promoters responding to activation of the MPK3 pathway such as Trxh8 and MYB44. Accordingly, plants overexpressing VIP1 accumulate high levels of Trxh8 and MYB44 transcripts, whereas stress-induced expression of these genes is impaired in mpk3 mutants. Trxh8 and MYB44 promoters are activated by VIP1 in a VRE-dependent manner. VIP1 strongly enhances expression from a synthetic promoter harboring multiple VRE copies and directly interacts with VREs in vitro and in vivo. Chromatin immunoprecipitation assays of the MYB44 promoter confirm that VIP1 binding to VREs is enhanced under conditions of MPK3 pathway stimulation. These results provide molecular insight into the cellular mechanism of target gene regulation by the MPK3 pathway. PMID:19820165

  13. Analysis of trace elements responsible for antioxidant protection by SRXFA method

    NASA Astrophysics Data System (ADS)

    Gonchar, A.; Kolmogorov, Yu; Dikalova, A.; Yelinova, V.; Kondratev, V.

    2001-09-01

    The possibilities of using the energy dispersion synchrotron radiation X-ray fluorescence analysis (SRXFA) for control of blood plasma and liver trace element (TE) content in rats with hyperproduction of oxygen radicals and hair TE content in women with mammary hyperplasia and cancer are demonstrated. Our data show that activity of antioxidant enzymes superoxide dismutase (SOD) and catalase in the blood and liver depends on the amount of TE incorporated into the structure of the active center of these enzymes, which are responsible for antioxidant protection. A decrease of activity of these enzymes is accompanied by an increase of production of free OH radicals in the tissues. Clinical data demonstrated that scalp hair of patients with oncological mammary pathology was characterized by a significant decrease of concentrations of selenium (Se) and zinc (Zn) and by an increase of chromium (Cr). The Se deficit was more pronounced in patients with cancer than in those with mammary hyperplasia ( p<0.05). The SRXFA method permits one to carry out a controllable correction of TE imbalance in many diseases whose development is caused by oxygen radical injury.

  14. Using Finite Element Simulation to Optimize the Heat Treatment of Tire Protection Chains

    NASA Astrophysics Data System (ADS)

    Eck, S.; Prevedel, P.; Marsoner, S.; Ecker, W.; Illmeier, M.

    2014-04-01

    The heat treatment of tire protection chains has a major influence on the final product because the high local stresses that arise during quenching may lead to material failure, i.e., quench cracks. The investigations presented in this paper aim at the identification of critical areas in the design of a tire chain link made of 50CrV4 (DIN 1.8159) steel. Parametric studies were conducted by means of finite element (FE) simulation. The FE model enables the calculation of the stress evolution in the chain link during heat treatment. The position of the cracks produced in laboratory quench experiments coincided with the position where the FE simulation model predicted the maximum tensile stress at the end of the quench. Hence, geometry optimization of the chain links is now possible by means of parametric FE studies aiming to minimize these tensile stresses. To identify the influence of the various input parameters on the calculated stress evolution during the quenching, a sensitivity analysis was performed. The influence of the mesh size, the heat transfer at the surface, and the thermo-mechanical properties of the material phases on the stress calculation was evaluated and trends were identified. Temperature measurements during quenching experiments were used to determine the heat transfer parameters. X-ray residual stress measurements on pre-defined positions after an instrumented laboratory quenching were used to validate the simulation results.

  15. Decay-accelerating factor protects human tumor cells from complement-mediated cytotoxicity in vitro.

    PubMed Central

    Cheung, N K; Walter, E I; Smith-Mensah, W H; Ratnoff, W D; Tykocinski, M L; Medof, M E

    1988-01-01

    The disialoganglioside GD2 is expressed on a wide spectrum of human tumor types, including neuroblastomas and melanomas. Upon binding of 3F8, a murine monoclonal antibody (MAb) specific for GD2, neuroblastomas and some melanomas are sensitive to killing by human complement, whereas some melanomas are not. To investigate the mechanism underlying these differences in complement mediated cytotoxicity, complement-insensitive melanoma cell lines were compared with respect to expression of the decay-accelerating factor (DAF), a membrane regulatory protein that protects blood cells from autologous complement attack. While DAF was undetectable among neuroblastomas, it was present in complement-insensitive melanomas. When the function of DAF was blocked by anti-DAF MAb, C3 uptake and complement-mediated lysis of the insensitive melanoma lines were markedly enhanced. F(ab')2 fragments were as effective in enhancing lysis as intact anti-DAF MAb. The DAF-negative and DAF-positive melanoma cell lines were comparably resistant to passive lysis by cobra venom factor-treated serum. The data suggest that in some tumors, DAF activity accounts for their resistance to complement-mediated killing. The ability to render these cells complement-sensitive by blocking DAF function may have implications for immunotherapy. PMID:2450893

  16. Hepcidin-mediated iron sequestration protects against bacterial dissemination during pneumonia

    PubMed Central

    Michels, Kathryn R.; Zhang, Zhimin; Bettina, Alexandra M.; Cagnina, R. Elaine; Stefanova, Debora; Burdick, Marie D.; Vaulont, Sophie; Nemeth, Elizabeta

    2017-01-01

    Gram-negative pneumonia is a dangerous illness, and bacterial dissemination to the bloodstream during the infection is strongly associated with death. Antibiotic resistance among the causative pathogens has resulted in diminishing treatment options against this infection. Hepcidin is the master regulator of extracellular iron availability in vertebrates, but its role in the context of host defense is undefined. We hypothesized that hepcidin-mediated depletion of extracellular iron during Gram-negative pneumonia protects the host by limiting dissemination of bacteria to the bloodstream. During experimental pneumonia, hepcidin was induced in the liver in an IL-6–dependent manner and mediated a rapid decline in plasma iron. In contrast, hepcidin-deficient mice developed a paradoxical increase in plasma iron during infection associated with profound susceptibility to bacteremia. Incubation of bacteria with iron-supplemented plasma enhanced bacterial growth in vitro, and systemic administration of iron to WT mice similarly promoted increased susceptibility to bloodstream infection. Finally, treatment with a hepcidin analogue restored hypoferremia in hepcidin-deficient hosts, mediated bacterial control, and improved outcomes. These data show hepcidin induction during pneumonia to be essential to preventing bacterial dissemination by limiting extracellular iron availability. Hepcidin agonists may represent an effective therapy for Gram-negative infections in patients with impaired hepcidin production or signaling. PMID:28352667

  17. Astrocyte Mediated Protection of Fetal Cerebral Cortical Neurons from Rotenone and Paraquat

    PubMed Central

    Rathinam, Mary Latha; Watts, Lora Talley; Narasimhan, Madhusudhanan; Riar, Amanjot Kaur; Mahimainathan, Lenin; Henderson, George.I.

    2012-01-01

    Primary cultures of fetal rat cortical neurons and astrocytes were used to test the hypothesis that astrocyte-mediated control of neuronal glutathione (GSH) is a potent factor in neuroprotection against rotenone and paraquat. In neurons, rotenone (0.025 to 1μM) for 4 and 24 h decreased viability as did paraquat (2 to 100μM). Rotenone (30nM) decreased neuronal viability and GSH by 24% and 30%, while ROS were increased by 56%. Paraquat (30μM) decreased neuronal viability and GSH by 36% and 70%, while ROS were increased by 23%. When neurons were co-cultured with astrocytes, their GSH increased 1.5 fold and 5 fold at 12 and 24 h. Co-culturing with astrocytes blocked neuronal death and damage by rotenone and paraquat. Astrocyte-mediated neuroprotection was dependent on the activity of components of the γ-glutamyl cycle. These studies illustrate the importance of astrocyte-mediated glutathione homeostasis for protection of neurons from rotenone and paraquat and the role of the γ-glutamyl cycle in this neuroprotection PMID:22301167

  18. Growth Hormone Mediates Its Protective Effect in Hepatic Apoptosis through Hnf6

    PubMed Central

    Wang, Kewei; Wang, Minhua; Gannon, Maureen

    2016-01-01

    Background and Aims Growth hormone (GH) not only supports hepatic metabolism but also protects against hepatocyte cell death. Hnf6 (or Oc1) belonging to the Onecut family of hepatocyte transcription factors known to regulate differentiated hepatic function, is a GH-responsive gene. We evaluate if GH mediates Hnf6 activity to attenuate hepatic apoptotic injury. Methods We used an animal model of hepatic apoptosis by bile duct ligation (BDL) with Hnf6 -/- (KO) mice in which hepatic Hnf6 was conditionally inactivated. GH was administered to adult wild type WT and KO mice for the 7 days of BDL to enhance Hnf6 expression. In vitro, primary hepatocytes derived from KO and WT liver were treated with LPS and hepatocyte apoptosis was assessed with and without GH treatment. Results In WT mice, GH treatment enhanced Hnf6 expression during BDL, inhibited Caspase -3, -8 and -9 responses and diminished hepatic apoptotic and fibrotic injury. GH-mediated upregulation of Hnf6 expression and parallel suppression of apoptosis and fibrosis in WT BDL liver were abrogated in KO mice. LPS activated apoptosis and suppressed Hnf6 expression in primary hepatocytes. GH/LPS co-treatment enhanced Hnf6 expression with corresponding attenuation of apoptosis in WT-derived hepatocytes, but not in KO hepatocytes. ChiP-on-ChiP and electromobility shift assays of KO and WT liver nuclear extracts identified Ciap1 (or Birc2) as an Hnf6-bound target gene. Ciap1 expression patterns closely follow Hnf6 expression in the liver and in hepatocytes. Conclusion GH broad protective actions on hepatocytes during liver injury are effected through Hnf6, with Hnf6 transcriptional activation of Ciap1 as an underlying molecular mediator. PMID:27936029

  19. Berberine Protects against Neuronal Damage via Suppression of Glia-Mediated Inflammation in Traumatic Brain Injury

    PubMed Central

    Lee, Chao Yu; Wang, Liang-Fei; Wu, Chun-Hu; Ke, Chia-Hua; Chen, Szu-Fu

    2014-01-01

    Traumatic brain injury (TBI) triggers a series of neuroinflammatory processes that contribute to evolution of neuronal injury. The present study investigated the neuroprotective effects and anti-inflammatory actions of berberine, an isoquinoline alkaloid, in both in vitro and in vivo TBI models. Mice subjected to controlled cortical impact injury were injected with berberine (10 mg·kg−1) or vehicle 10 min after injury. In addition to behavioral studies and histology analysis, blood-brain barrier (BBB) permeability and brain water content were determined. Expression of PI3K/Akt and Erk signaling and inflammatory mediators were also analyzed. The protective effect of berberine was also investigated in cultured neurons either subjected to stretch injury or exposed to conditioned media with activated microglia. Berberine significantly attenuated functional deficits and brain damage associated with TBI up to day 28 post-injury. Berberine also reduced neuronal death, apoptosis, BBB permeability, and brain edema at day 1 post-injury. These changes coincided with a marked reduction in leukocyte infiltration, microglial activation, matrix metalloproteinase-9 activity, and expression of inflammatory mediators. Berberine had no effect on Akt or Erk 1/2 phosphorylation. In mixed glial cultures, berberine reduced TLR4/MyD88/NF-κB signaling. Berberine also attenuated neuronal death induced by microglial conditioned media; however, it did not directly protect cultured neurons subjected to stretch injury. Moreover, administration of berberine at 3 h post-injury also reduced TBI-induced neuronal damage, apoptosis and inflammation in vivo. Berberine reduces TBI-induced brain damage by limiting the production of inflammatory mediators by glial cells, rather than by a direct neuroprotective effect. PMID:25546475

  20. C-reactive protein mediates protection from lipopolysaccharide through interactions with Fc gamma R.

    PubMed

    Mold, Carolyn; Rodriguez, Wilfredo; Rodic-Polic, Bojana; Du Clos, Terry W

    2002-12-15

    C-reactive protein (CRP) is a component of the acute phase response to infection, inflammation, and trauma. A major activity of acute phase proteins is to limit the inflammatory response. It has been demonstrated that CRP protects mice from lethal doses of LPS. In the mouse, CRP binds to the regulatory receptor, FcgammaRIIb, and to the gamma-chain-associated receptor, FcgammaRI. The goal ofthis study was to determine whether FcgammaRs are necessary for the protective effect of CRP. The ability of CRP to protect mice from a lethal dose of LPS was confirmed using injections of 500 and 250 micro g of CRP at 0 and 12 h. CRP treatment of FcgammaRIIb-deficient mice increased mortality after LPS challenge and increased serum levels of TNF and IL-12 in response to LPS. CRP did not protect FcR gamma-chain-deficient mice from LPS-induced mortality. Treatment of normal mice, but not gamma-chain-deficient mice, with CRP increased IL-10 levels following LPS injection. In vitro, in the presence of LPS, CRP enhanced IL-10 synthesis and inhibited IL-12 synthesis by bone marrow macrophages from normal, but not gamma-chain-deficient mice. The protective effect of CRP appears to be mediated by binding to FcgammaRI and FcgammaRII resulting in enhanced secretion of the anti-inflammatory cytokine IL-10 and the down-regulation of IL-12. These results suggest that CRP can alter the cytokine profile of mouse macrophages by acting through FcgammaR leading to a down-regulation of the inflammatory response.

  1. PROTECTIVE EFFECTS OF PHYLLANTHUS EMBLICA LEAF EXTRACT ON SODIUM ARSENITE-MEDIATED ADVERSE EFFECTS IN MICE

    PubMed Central

    SAYED, SADIA; AHSAN, NAZMUL; KATO, MASASHI; OHGAMI, NOBUTAKA; RASHID, ABDUR; AKHAND, ANWARUL AZIM

    2015-01-01

    ABSTRACT Groundwater contamination of arsenic is the major cause of a serious health hazard in Bangladesh. No specific treatment is yet available to manage the large number of individuals exposed to arsenic. In this study, we evaluated the protective effects of Phyllanthus emblica (Indian gooseberry or Amla) leaf extract (PLE) on arsenic-mediated toxicity in experimental mice. Male Swiss albino mice were divided into three different groups (n=6/group). ‘Control’ mice received arsenic free water together with normal feed. Mice in the remaining two groups designated ‘SA’ and ‘SA+PLE’ were exposed to sodium arsenite (SA, 10 µg/g body weight/day) through drinking water in addition to receiving normal feed and PLE-supplemented feed, respectively. The weight gain of SA-exposed mice was decreased compared with the controls; however, this decrease in body weight gain was prevented when the feed was supplemented with PLE. A secondary effect of arsenic was enlargement of the liver, kidney and spleen of SA-group mice. Deposition of arsenic in those organs was demonstrated by ICP-MS. When PLE was supplemented in the feed the enlargement of the organs was minimized; however, the deposition of arsenic was not significantly reduced. These results indicated that PLE may not block arsenic deposition in tissue directly but rather may play a protective role to reduce arsenic-induced toxicity. Therefore, co-administration of PLE in arsenic-exposed animals might have a future therapeutic application for protecting against arsenic-mediated toxicity. PMID:25797979

  2. Thrombomodulin Contributes to Gamma Tocotrienol-Mediated Lethality Protection and Hematopoietic Cell Recovery in Irradiated Mice

    PubMed Central

    Pathak, Rupak; Shao, Lijian; Ghosh, Sanchita P.; Zhou, Daohong; Boerma, Marjan; Weiler, Hartmut; Hauer-Jensen, Martin

    2015-01-01

    Systemic administration of recombinant thrombomodulin (TM) confers radiation protection partly by accelerating hematopoietic recovery. The uniquely potent radioprotector gamma tocotrienol (GT3), in addition to being a strong antioxidant, inhibits the enzyme hydroxy-methyl-glutaryl-coenzyme A reductase (HMGCR) and thereby likely modulates the expression of TM. We hypothesized that the mechanism underlying the exceptional radioprotective properties of GT3 partly depends on the presence of endothelial TM. In vitro studies confirmed that ionizing radiation suppresses endothelial TM (about 40% at 4 hr after 5 Gy γ-irradiation) and that GT3 induces TM expression (about 2 fold at the mRNA level after 5 μM GT3 treatment for 4 hr). In vivo survival studies showed that GT3 was significantly more effective as a radioprotector in TM wild type (TM+/+) mice than in mice with low TM function (TMPro/-). After exposure to 9 Gy TBI, GT3 pre-treatment conferred 85% survival in TM+/+ mice compared to only 50% in TMPro/-. Thus, GT3-mediated radiation lethality protection is partly dependent on endothelial TM. Significant post-TBI recovery of hematopoietic cells, particularly leukocytes, was observed in TM+/+ mice (p = 0.003), but not in TMPro/- mice, despite the fact that GT3 induced higher levels of granulocyte colony stimulating factor (G-CSF) in TMPro/- mice (p = 0.0001). These data demonstrate a critical, G-CSF-independent, role for endothelial TM in GT3-mediated lethality protection and hematopoietic recovery after exposure to TBI and may point to new strategies to enhance the efficacy of current medical countermeasures in radiological/nuclear emergencies. PMID:25860286

  3. Drug Transporter-Mediated Protection of Cancer Stem Cells From Ionophore Antibiotics.

    PubMed

    Boesch, Maximilian; Zeimet, Alain G; Rumpold, Holger; Gastl, Guenther; Sopper, Sieghart; Wolf, Dominik

    2015-09-01

    Ionophore antibiotics were reported to selectively kill cancer stem cells and to overcome multidrug resistance, but mechanistic studies of the significance of drug transporters for treatment with these compounds are lacking. We applied chemosensitivity testing of well-characterized human cancer cell lines to elaborate on whether drug transporters are involved in protection from the cytotoxic effects of the ionophore antibiotics salinomycin and nigericin. Our experiments demonstrated that ionophore antibiotics were ineffective against both stem-like ovarian cancer side population cells (expressing either ABCB1 or ABCG2) and K562/Dox-H1 cells, which constitute a genetically defined model system for ABCB1 expression. Considering that cancer stem cells often express high levels of drug transporters, we deduced from our results that ionophore antibiotics are less suited to cancer stem cell-targeted treatment than previously thought. Ionophore antibiotics such as salinomycin have repeatedly been shown to target cancer stem and progenitor cells from various tumor entities. Meanwhile, cancer stem cell (CSC)-selective toxicity of ionophore antibiotics seems to be a commonly accepted concept that is about to encourage their clinical testing. This study provides data that challenge the concept of targeted elimination of CSC by ionophore antibiotics. Stem-like ovarian cancer side population (SP) cells expressing high levels of ABC drug transporters are shown to largely resist the cytotoxic effects of salinomycin and nigericin. Furthermore, using a small interfering RNA-based knockdown model specific for ABCB1, this study demonstrates that ABC drug transporters are indeed causally involved in mediating protection from ionophore antibiotics. Considering that it is a hallmark of CSCs to exhibit drug resistance conferred by ABC drug transporters, it must be deduced from these results that CSCs may also be protected from ionophore antibiotics by means of drug-transporter mediated

  4. Drug Transporter-Mediated Protection of Cancer Stem Cells From Ionophore Antibiotics

    PubMed Central

    Zeimet, Alain G.; Rumpold, Holger; Gastl, Guenther; Sopper, Sieghart; Wolf, Dominik

    2015-01-01

    Ionophore antibiotics were reported to selectively kill cancer stem cells and to overcome multidrug resistance, but mechanistic studies of the significance of drug transporters for treatment with these compounds are lacking. We applied chemosensitivity testing of well-characterized human cancer cell lines to elaborate on whether drug transporters are involved in protection from the cytotoxic effects of the ionophore antibiotics salinomycin and nigericin. Our experiments demonstrated that ionophore antibiotics were ineffective against both stem-like ovarian cancer side population cells (expressing either ABCB1 or ABCG2) and K562/Dox-H1 cells, which constitute a genetically defined model system for ABCB1 expression. Considering that cancer stem cells often express high levels of drug transporters, we deduced from our results that ionophore antibiotics are less suited to cancer stem cell-targeted treatment than previously thought. Significance Ionophore antibiotics such as salinomycin have repeatedly been shown to target cancer stem and progenitor cells from various tumor entities. Meanwhile, cancer stem cell (CSC)-selective toxicity of ionophore antibiotics seems to be a commonly accepted concept that is about to encourage their clinical testing. This study provides data that challenge the concept of targeted elimination of CSC by ionophore antibiotics. Stem-like ovarian cancer side population (SP) cells expressing high levels of ABC drug transporters are shown to largely resist the cytotoxic effects of salinomycin and nigericin. Furthermore, using a small interfering RNA-based knockdown model specific for ABCB1, this study demonstrates that ABC drug transporters are indeed causally involved in mediating protection from ionophore antibiotics. Considering that it is a hallmark of CSCs to exhibit drug resistance conferred by ABC drug transporters, it must be deduced from these results that CSCs may also be protected from ionophore antibiotics by means of drug

  5. Basophil-mediated protection against gastrointestinal helminths requires IgE-induced cytokine secretion

    PubMed Central

    Schwartz, Christian; Turqueti-Neves, Adriana; Hartmann, Susanne; Yu, Philipp; Nimmerjahn, Falk; Voehringer, David

    2014-01-01

    Basophils orchestrate protection against reinfections with gastrointestinal helminths and ticks, but the underlying mechanisms remain elusive. We investigated the role of Fc receptors on basophils, the antibody isotypes IgG1 and IgE, and basophil-derived IL-4/IL-13 during challenge infections with Heligmosomoides polygyrus and Nippostrongylus brasiliensis. Using mixed bone marrow chimeras, we found that activating Fc receptors on basophils were required for protective immunity but not for regulation of basophil homeostasis. Furthermore, rapid worm expulsion was impaired in IgE-deficient but not in IgG1-deficient mice. Basophils promoted the recruitment of other effector cells into the small intestine and induced expression of the antihelminthic proteins resistin-like molecule β and mucin 5ac. Selective deletion of IL-4/IL-13 in basophils resulted in impaired worm expulsion. Collectively, our results indicate that IgE-mediated activation of basophils and the release of basophil-derived IL-4/IL-13 are critical steps in protective immunity against helminths. Therefore, development of effective vaccines against helminths should consider boosting the IL-4/IgE/basophil axis of the immune system. PMID:25404305

  6. Anti-pathogen protection versus survival costs mediated by an ectosymbiont in an ant host

    PubMed Central

    Konrad, Matthias; Grasse, Anna V.; Tragust, Simon; Cremer, Sylvia

    2015-01-01

    The fitness effects of symbionts on their hosts can be context-dependent, with usually benign symbionts causing detrimental effects when their hosts are stressed, or typically parasitic symbionts providing protection towards their hosts (e.g. against pathogen infection). Here, we studied the novel association between the invasive garden ant Lasius neglectus and its fungal ectosymbiont Laboulbenia formicarum for potential costs and benefits. We tested ants with different Laboulbenia levels for their survival and immunity under resource limitation and exposure to the obligate killing entomopathogen Metarhizium brunneum. While survival of L. neglectus workers under starvation was significantly decreased with increasing Laboulbenia levels, host survival under Metarhizium exposure increased with higher levels of the ectosymbiont, suggesting a symbiont-mediated anti-pathogen protection, which seems to be driven mechanistically by both improved sanitary behaviours and an upregulated immune system. Ants with high Laboulbenia levels showed significantly longer self-grooming and elevated expression of immune genes relevant for wound repair and antifungal responses (β-1,3-glucan binding protein, Prophenoloxidase), compared with ants carrying low Laboulbenia levels. This suggests that the ectosymbiont Laboulbenia formicarum weakens its ant host by either direct resource exploitation or the costs of an upregulated behavioural and immunological response, which, however, provides a prophylactic protection upon later exposure to pathogens. PMID:25473011

  7. An endothelial TLR4-VEGFR2 pathway mediates lung protection against oxidant-induced injury.

    PubMed

    Takyar, Seyedtaghi; Zhang, Yi; Haslip, Maria; Jin, Lei; Shan, Peiying; Zhang, Xuchen; Lee, Patty J

    2016-03-01

    TLR4 deficiency causes hypersusceptibility to oxidant-induced injury. We investigated the role of TLR4 in lung protection, using used bone marrow chimeras; cell-specific transgenic modeling; and lentiviral delivery in vivo to knock down or express TLR4 in various lung compartments; and lung-specific VEGF transgenic mice to investigate the effect of TLR4 on VEGF-mediated protection. C57/BL6 mice were exposed to 100% oxygen in an enclosed chamber and assessed for survival and lung injury. Primary endothelial cells were stimulated with recombinant VEGF and exposed to hyperoxia or hydrogen peroxide. Endothelium-specific expression of human TLR4 (as opposed to its expression in epithelium or immune cells) increased the survival of TLR4-deficent mice in hyperoxia by 24 h and decreased LDH release and lung cell apoptosis after 72 h of exposure by 30%. TLR4 expression was necessary and sufficient for the protective effect of VEGF in the lungs and in primary endothelial cells in culture. TLR4 knockdown inhibited VEGF signaling through VEGF receptor 2 (VEGFR2), Akt, and ERK pathways in lungs and primary endothelial cells and decreased the availability of VEGFR2 at the cell surface. These findings demonstrate a novel mechanism through which TLR4, an innate pattern receptor, interacts with an endothelial survival pathway.

  8. SOD2 Mediates Amifostine-Induced Protection against Glutamate in PC12 Cells

    PubMed Central

    Jia, Ji; Zhang, Lei; Shi, Xiaolei; Wu, Mingchun; Zhou, Xiang; Liu, Xiaonan; Huo, Tingting

    2016-01-01

    Background. Cytoprotectant amifostine attenuates radiation-induced oxidative injury by increasing intracellular manganese superoxide dismutase (SOD2) in peripheral tissue. However, whether amifostine could protect neuronal cells against oxidative injury has not been reported. The purpose of this study is to explore the protection of amifostine in PC12 cells. Methods. PC12 cells exposed to glutamate were used to mimic neuronal oxidative injury. SOD assay kit was taken to evaluate intracellular Cu/Zn SOD (SOD1) and SOD2 activities; western blot analysis and immunofluorescence staining were performed to investigate SOD2 protein expression; MTT, lactate dehydrogenase (LDH), release and cell morphology were used to evaluate cell injury degree, and apoptotic rate and cleaved caspase-3 expression were taken to assess apoptosis; mitochondrial superoxide production, intracellular reactive oxygen species (ROS), and glutathione (GSH) and catalase (CAT) levels were evaluated by reagent kits. Results. Amifostine increased SOD2 activity and expression, decreased cell injury and apoptosis, reduced mitochondrial superoxide production and intracellular ROS generation, and restored intracellular GSH and CAT levels in PC12 cells exposed to glutamate. SOD2-siRNA, however, significantly reversed the amifostine-induced cytoprotective and antioxidative actions. Conclusion. SOD2 mediates amifostine-induced protection in PC12 cells exposed to glutamate. PMID:26770652

  9. Immunization with heat-killed Francisella tularensis LVS elicits protective antibody-mediated immunity.

    PubMed

    Lavine, Christy L; Clinton, Shawn R; Angelova-Fischer, Irena; Marion, Tony N; Bina, Xiaowen R; Bina, James E; Whitt, Michael A; Miller, Mark A

    2007-11-01

    Francisella tularensis (FT) has been classified by the CDC as a category A pathogen because of its high virulence and the high mortality rate associated with infection via the aerosol route. Because there is no licensed vaccine available for FT, development of prophylactic and therapeutic regimens for the prevention/treatment of infection is a high priority. In this report, heat-killed FT live vaccine strain (HKLVS) was employed as a vaccine immunogen, either alone or in combination with an adjuvant, and was found to elicit protective immunity against high-dose FT live vaccine strain (FTLVS) challenge. FT-specific antibodies produced in response to immunization with HKLVS alone were subsequently found to completely protect naive mice against high-dose FT challenge in both infection-interference and passive immunization experiments. Additional passive immunization trials employing serum collected from mice immunized with a heat-killed preparation of an O-antigen-deficient transposon mutant of FTLVS (HKLVS-OAg(neg)) yielded similar results. These findings demonstrated that FT-specific antibodies alone can confer immunity against high-dose FTLVS challenge, and they reveal that antibody-mediated protection is not dependent upon production of LPS-specific antibodies.

  10. Non-additive interactions involving two distinct elements mediate sloppy-paired regulation by pair-rule transcription factors

    PubMed Central

    Prazak, Lisa; Fujioka, Miki; Gergen, J. Peter

    2010-01-01

    The relatively simple combinatorial rules responsible for establishing the initial metameric expression of sloppy-paired-1 (slp1) in the Drosophila blastoderm embryo make this system an attractive model for investigating the mechanism of regulation by pair rule transcription factors. This investigation of slp1 cis-regulatory architecture identifies two distinct elements, a proximal early stripe element (PESE) and a distal early stripe element (DESE) located from −3.1 kb to −2.5 kb and from −8.1 kb to −7.1 kb upstream of the slp1 promoter, respectively, that mediate this early regulation. The proximal element expresses only even-numbered stripes and mediates repression by Even-skipped (Eve) as well as by the combination of Runt and Fushi-tarazu (Ftz). A 272 basepair sub-element of PESE retains Eve-dependent repression, but is expressed throughout the even-numbered parasegments due to the loss of repression by Runt and Ftz. In contrast, the distal element expresses both odd and even-numbered stripes and also drives inappropriate expression in the anterior half of the odd-numbered parasegments due to an inability to respond to repression by Eve. Importantly, a composite reporter gene containing both early stripe elements recapitulates pair-rule gene-dependent regulation in a manner beyond what is expected from combining their individual patterns. These results indicate interactions involving distinct cis-elements contribute to the proper integration of pair-rule regulatory information. A model fully accounting for these results proposes that metameric slp1 expression is achieved through the Runt-dependent regulation of interactions between these two pair-rule response elements and the slp1 promoter. PMID:20435028

  11. Protective effect of tert-butylhydroquinone on the quinolinic-acid-induced toxicity in rat striatal slices: role of the Nrf2-antioxidant response element pathway.

    PubMed

    Tasset, Inmaculada; Pérez-De La Cruz, Verónica; Elinos-Calderón, Diana; Carrillo-Mora, Paul; González-Herrera, Irma Gabriela; Luna-López, Armando; Konigsberg, Mina; Pedraza-Chaverrí, José; Maldonado, Perla D; Ali, Syed F; Túnez, Isaac; Santamaría, Abel

    2010-01-01

    Tert-butylhydroquinone (tBHQ) is a xenobiotic with reported antioxidant properties. tBHQ has been shown to induce nuclear translocation of the transcription factor NF-E2-related factor 2 (Nrf2) to further activate the antioxidant response element (ARE). In turn, the Nrf2/ARE pathway is responsible for the induction of phase 2 antioxidant enzymes that detoxify oxidant promoters from different toxic insults. In this work, the antioxidant and protective actions of tBHQ were explored for the first time on different biomarkers of the neurotoxic model produced by the excitotoxic and pro-oxidant molecule quinolinic acid (QUIN) in rat striatal slices. For comparison purposes, 3-nitropropionic acid was used as reference model. Our results show that tBHQ (25 μM) prevented the QUIN-induced lipid peroxidation and mitochondrial dysfunction. In addition, tBHQ enhanced glutathione-S-transferase activity, partially recovering its depletion induced by QUIN treatment. Our results also demonstrated that tBHQ was able to induce nuclear accumulation of Nrf2 and further antioxidant protection: while QUIN alone decreased the nuclear Nrf2, a treatment with tBHQ preserved the nuclear levels Nrf2 in the presence of QUIN. Therefore, the tBHQ-mediated Nrf2/ARE induction constitutes a signaling-mediated antioxidant strategy and therapeutic tool to be tested in different neurotoxic models. Copyright © 2009 S. Karger AG, Basel.

  12. Zinc-Dependent Protection of Tobacco and Rice Cells From Aluminum-Induced Superoxide-Mediated Cytotoxicity.

    PubMed

    Lin, Cun; Hara, Ayaka; Comparini, Diego; Bouteau, François; Kawano, Tomonori

    2015-01-01

    Al(3+) toxicity in growing plants is considered as one of the major factors limiting the production of crops on acidic soils worldwide. In the last 15 years, it has been proposed that Al(3+) toxicity are mediated with distortion of the cellular signaling mechanisms such as calcium signaling pathways, and production of cytotoxic reactive oxygen species (ROS) causing oxidative damages. On the other hand, zinc is normally present in plants at high concentrations and its deficiency is one of the most widespread micronutrient deficiencies in plants. Earlier studies suggested that lack of zinc often results in ROS-mediated oxidative damage to plant cells. Previously, inhibitory action of Zn(2+) against lanthanide-induced superoxide generation in tobacco cells have been reported, suggesting that Zn(2+) interferes with the cation-induced ROS production via stimulation of NADPH oxidase. In the present study, the effect of Zn(2+) on Al(3+)-induced superoxide generation in the cell suspension cultures of tobacco (Nicotiana tabacum L., cell-line, BY-2) and rice (Oryza sativa L., cv. Nipponbare), was examined. The Zn(2+)-dependent inhibition of the Al(3+)-induced oxidative burst was observed in both model cells selected from the monocots and dicots (rice and tobacco), suggesting that this phenomenon (Al(3+)/Zn(2+) interaction) can be preserved in higher plants. Subsequently induced cell death in tobacco cells was analyzed by lethal cell staining with Evans blue. Obtained results indicated that presence of Zn(2+) at physiological concentrations can protect the cells by preventing the Al(3+)-induced superoxide generation and cell death. Furthermore, the regulation of the Ca(2+) signaling, i.e., change in the cytosolic Ca(2+) ion concentration, and the cross-talks among the elements which participate in the pathway were further explored.

  13. Reduction of AUF1-mediated follistatin mRNA decay during glucose starvation protects cells from apoptosis.

    PubMed

    Gao, Xiangwei; Dong, Haojie; Lin, Chen; Sheng, Jinghao; Zhang, Fan; Su, Jinfeng; Xu, Zhengping

    2014-01-01

    Follistatin (FST) performs several vital functions in the cells, including protection from apoptosis during stress. The expression of FST is up-regulated in response to glucose deprivation by an unknown mechanism. We herein showed that the induction of FST by glucose deprivation was due to an increase in the half-life of its mRNA. We further identified an AU-rich element (ARE) in the 3'UTR of FST mRNA that mediated its decay. The expression of FST was elevated after knocking down AUF1 and reduced when AUF1 was further expressed. In vitro binding assays and RNA pull-down assays revealed that AUF1 interacted with FST mRNA directly via its ARE. During glucose deprivation, a majority of AUF1 shuttled from cytoplasm to nucleus, resulting in dissociation of AUF1 from FST mRNA and thus stabilization of FST mRNA. Finally, knockdown of AUF1 decreased whereas overexpression of AUF1 increased glucose deprivation-induced apoptosis. The apoptosis promoting effect of AUF1 was eliminated in FST expressing cells. Collectively, this study provided evidence that AUF1 is a negative regulator of FST expression and participates in the regulation of cell survival under glucose deprivation.

  14. Reduction of AUF1-mediated follistatin mRNA decay during glucose starvation protects cells from apoptosis

    PubMed Central

    Gao, Xiangwei; Dong, Haojie; Lin, Chen; Sheng, Jinghao; Zhang, Fan; Su, Jinfeng; Xu, Zhengping

    2014-01-01

    Follistatin (FST) performs several vital functions in the cells, including protection from apoptosis during stress. The expression of FST is up-regulated in response to glucose deprivation by an unknown mechanism. We herein showed that the induction of FST by glucose deprivation was due to an increase in the half-life of its mRNA. We further identified an AU-rich element (ARE) in the 3′UTR of FST mRNA that mediated its decay. The expression of FST was elevated after knocking down AUF1 and reduced when AUF1 was further expressed. In vitro binding assays and RNA pull-down assays revealed that AUF1 interacted with FST mRNA directly via its ARE. During glucose deprivation, a majority of AUF1 shuttled from cytoplasm to nucleus, resulting in dissociation of AUF1 from FST mRNA and thus stabilization of FST mRNA. Finally, knockdown of AUF1 decreased whereas overexpression of AUF1 increased glucose deprivation-induced apoptosis. The apoptosis promoting effect of AUF1 was eliminated in FST expressing cells. Collectively, this study provided evidence that AUF1 is a negative regulator of FST expression and participates in the regulation of cell survival under glucose deprivation. PMID:25159612

  15. Carnitine supplementation has protective and detrimental effects in Saccharomyces cerevisiae that are genetically mediated.

    PubMed

    Franken, Jaco; Bauer, Florian F

    2010-05-01

    l-Carnitine plays a well-documented role in eukaryotic energy homeostasis by acting as a shuttling molecule for activated acyl residues across intracellular membranes. This activity, supported by carnitine acyl-transferases and transporters, is referred to as the carnitine shuttle. However, several pleiotropic and often beneficial effects of carnitine in humans have been reported that appear to be unrelated to shuttling activity, but little conclusive evidence regarding molecular mechanisms exists. We have recently demonstrated a role of carnitine, independent of the carnitine shuttle, in yeast stress protection. Here, we show that carnitine specifically protects against oxidative stress caused by H(2)O(2) and the superoxide-generating agent menadione. Surprisingly, carnitine has a detrimental effect on survival when combined with thiol-modifying agents. Central elements of the oxidative stress response, specifically the transcription factors Yap1p and Skn7p, are shown to be required for carnitine's protective effect, but several downstream effectors are dispensable. A DNA microarray-based analysis identifies Cyc3p, a cytochrome c heme lyase, as being important for carnitine's impact during oxidative stress. These findings establish a direct genetic link to a carnitine-related phenotype that is independent of the shuttle system and suggests that Saccharomyces cerevisiae should provide a useful model for further elucidation of carnitine's physiological roles.

  16. Similar cation channels mediate protection from cerebellar exitotoxicity by exercise and inheritance.

    PubMed

    Ben-Ari, Shani; Ofek, Keren; Barbash, Shahar; Meiri, Hanoch; Kovalev, Eugenia; Greenberg, David Samuel; Soreq, Hermona; Shoham, Shai

    2012-03-01

    Exercise and inherited factors both affect recovery from stroke and head injury, but the underlying mechanisms and interconnections between them are yet unknown. Here, we report that similar cation channels mediate the protective effect of exercise and specific genetic background in a kainate injection model of cerebellar stroke. Microinjection to the cerebellum of the glutamatergic agonist, kainate, creates glutamatergic excito\\xE2\\x80\\x90toxicity characteristic of focal stroke, head injury or alcoholism. Inherited protection and prior exercise were both accompanied by higher cerebellar expression levels of the Kir6.1 ATP-dependent potassium channel in adjacent Bergmann glia, and voltage-gated KVbeta2 and cyclic nucleotide-gated cation HCN1 channels in basket cells. Sedentary FVB/N and exercised C57BL/6 mice both expressed higher levels of these cation channels compared to sedentary C57BL/6 mice, and were both found to be less sensitive to glutamate toxicity. Moreover, blocking ATP-dependent potassium channels with Glibenclamide enhanced kainate-induced cell death in cerebellar slices from the resilient sedentary FVB/N mice. Furthermore, exercise increased the number of acetylcholinesterase-positive fibres in the molecular layer, reduced cerebellar cytokine levels and suppressed serum acetylcholinesterase activity, suggesting anti-inflammatory protection by enhanced cholinergic signalling. Our findings demonstrate for the first time that routine exercise and specific genetic backgrounds confer protection from cerebellar glutamatergic damages by similar molecular mechanisms, including elevated expression of cation channels. In addition, our findings highlight the involvement of the cholinergic anti-inflammatory pathway in insult-inducible cerebellar processes. These mechanisms are likely to play similar roles in other brain regions and injuries as well, opening new venues for targeted research efforts.

  17. Experimental Studies on Cholera Immunization II. Evidence for Protective Antitoxic Immunity Mediated by Serum Antibodies as Well as Local Antibodies

    PubMed Central

    Holmgren, J.; Andersson, Å.; Wallerstrom, G.; Ouchterlony, Ö.

    1972-01-01

    By use of the ileal loop technique, the resistance to challenge with cholera enterotoxin was compared between unimmunized rabbits and rabbits immunized with toxin or toxoids. It was shown that subcutaneous as well as intraintestinal immunization induced protective immunity, the toxin being a better immunogen than Formalin-induced toxoid and much better than heat-induced toxoid. The relation between protection and serum antitoxin titer was poor, e.g., protection was seen in the absence of demonstrable serum antibodies. However, intravenous administration of antitoxic antiserum conferred some protection, suggesting that local as well as serum-mediated antitoxic immunity is operating in the host defence against cholera. PMID:4637602

  18. CDK4-mediated MnSOD activation and mitochondrial homeostasis in radioadaptive protection

    PubMed Central

    Jin, Cuihong; Qin, Lili; Shi, Yan; Candas, Demet; Fan, Ming; Lu, Chung-Ling; Vaughan, Andrew T. M.; Shen, Rulong; Wu, Larry S.; Liu, Rui; Li, Robert F.; Murley, Jeffrey S.; Gayle, Woloschak; Grdina, David J.; Li, Jian Jian

    2015-01-01

    Mammalian cells are able to sense environmental oxidative and genotoxic conditions such as the environmental low dose ionizing radiation (LDIR) present naturally on earth surface. The stressed cells then can induce a so-called radioadaptive response with an enhanced cellular homeostasis and repair capacity against subsequent similar genotoxic conditions such as a high dose radiation. MnSOD, a primary mitochondrial antioxidant in mammals, has long been known to play a crucial role in the radioadaptive protection through detoxifying O2·- generated by mitochondrial oxidative phosphorylation. Contrasted to the well-studied mechanisms of SOD2 gene regulation, the mechanisms underlying post-translational regulation of MnSOD for radioprotection remain to be defined. Herein, we demonstrate that Cyclin D1-cyclin-dependent kinase 4 (CDK4) serves as the messenger to deliver the stress signal to mitochondria to boost mitochondrial homeostasis in human skin keratinocytes under LDIR adaptive radioprotection. Cyclin D1/CDK4 is found to relocate to mitochondria at the same time as MnSOD enzymatic activation peaks without significant changes of total MnSOD protein level. The mitochondrial-localized CDK4 directly phosphorylates MnSOD at Serine 106 (S106), causing enhanced MnSOD enzymatic activity and mitochondrial respiration. Expression of mitochondria-targeted dominant negative CDK4 or the MnSOD-S106A mutant reverses LDIR-induced mitochondrial enhancement and adaptive protection. The CDK4-mediated MnSOD activation and mitochondrial metabolism boost are also detected in skin tissues of mice receiving in vivo whole body LDIR. These results demonstrate a unique CDK4-mediated mitochondrial communication that allows cells to sense environmental genotoxic stress and boost mitochondrial homeostasis via enhancing phosphorylation and activation of MnSOD. PMID:25578653

  19. Protection by Salidroside against Bone Loss via Inhibition of Oxidative Stress and Bone-Resorbing Mediators

    PubMed Central

    Yuan, Zhi; Fan, Jing; Li, Dan; Chen, Jian-Zong; Shi, Tian-Yao; Hu, Hui-Min; Wei, Bo-Yuan; Luo, Zhuo-Jing; Liu, Jian

    2013-01-01

    Oxidative stress is a pivotal pathogenic factor for bone loss in mouse model. Salidroside, a phenylpropanoid glycoside extracted from Rhodiola rosea L, exhibits potent antioxidative effects. In the present study, we used an in vitro oxidative stress model induced by hydrogen peroxide (H2O2) in MC3T3-E1 cells and a murine ovariectomized (OVX) osteoporosis model to investigate the protective effects of salidroside on bone loss and the related mechanisms. We demonstrated that salidroside caused a significant (P<0.05) elevation of cell survival, alkaline phosphatase (ALP) staining and activity, calcium deposition, and the transcriptional expression of Alp, Col1a1 and Osteocalcin (Ocn) in the presence of H2O2. Moreover, salidroside decreased the production of intracellular reactive oxygen species (ROS), and osteoclast differentiation inducing factors such as receptor activator of nuclear factor-kB ligand (RANKL) and IL-6 induced by H2O2. In vivo studies further demonstrated that salidroside supplementation for 3 months caused a decrease in malondialdehyde (MDA) and an increase in reduced glutathione (GSH) concentration in blood of ovariectomized mouse (P<0.05), it also improved trabecular bone microarchitecture and bone mineral density in the fourth lumbar vertebra and distal femur. Our study indicated that the protection provided by salidroside in alleviating bone loss was mediated, at least in part, via inhibition of the release of bone-resorbing mediators and oxidative damage to bone-forming cells, suggesting that salidroside can be used as an effective remedy in the treatment or prevention of osteoporosis. PMID:23437352

  20. Protection by salidroside against bone loss via inhibition of oxidative stress and bone-resorbing mediators.

    PubMed

    Zhang, Jin-Kang; Yang, Liu; Meng, Guo-Lin; Yuan, Zhi; Fan, Jing; Li, Dan; Chen, Jian-Zong; Shi, Tian-Yao; Hu, Hui-Min; Wei, Bo-Yuan; Luo, Zhuo-Jing; Liu, Jian

    2013-01-01

    Oxidative stress is a pivotal pathogenic factor for bone loss in mouse model. Salidroside, a phenylpropanoid glycoside extracted from Rhodiola rosea L, exhibits potent antioxidative effects. In the present study, we used an in vitro oxidative stress model induced by hydrogen peroxide (H(2)O(2)) in MC3T3-E1 cells and a murine ovariectomized (OVX) osteoporosis model to investigate the protective effects of salidroside on bone loss and the related mechanisms. We demonstrated that salidroside caused a significant (P<0.05) elevation of cell survival, alkaline phosphatase (ALP) staining and activity, calcium deposition, and the transcriptional expression of Alp, Col1a1 and Osteocalcin (Ocn) in the presence of H(2)O(2). Moreover, salidroside decreased the production of intracellular reactive oxygen species (ROS), and osteoclast differentiation inducing factors such as receptor activator of nuclear factor-kB ligand (RANKL) and IL-6 induced by H(2)O(2). In vivo studies further demonstrated that salidroside supplementation for 3 months caused a decrease in malondialdehyde (MDA) and an increase in reduced glutathione (GSH) concentration in blood of ovariectomized mouse (P<0.05), it also improved trabecular bone microarchitecture and bone mineral density in the fourth lumbar vertebra and distal femur. Our study indicated that the protection provided by salidroside in alleviating bone loss was mediated, at least in part, via inhibition of the release of bone-resorbing mediators and oxidative damage to bone-forming cells, suggesting that salidroside can be used as an effective remedy in the treatment or prevention of osteoporosis.

  1. CDK4-mediated MnSOD activation and mitochondrial homeostasis in radioadaptive protection.

    PubMed

    Jin, Cuihong; Qin, Lili; Shi, Yan; Candas, Demet; Fan, Ming; Lu, Chung-Ling; Vaughan, Andrew T M; Shen, Rulong; Wu, Larry S; Liu, Rui; Li, Robert F; Murley, Jeffrey S; Woloschak, Gayle; Grdina, David J; Li, Jian Jian

    2015-04-01

    Mammalian cells are able to sense environmental oxidative and genotoxic conditions such as the environmental low-dose ionizing radiation (LDIR) present naturally on the earth's surface. The stressed cells then can induce a so-called radioadaptive response with an enhanced cellular homeostasis and repair capacity against subsequent similar genotoxic conditions such as a high dose radiation. Manganese superoxide dismutase (MnSOD), a primary mitochondrial antioxidant in mammals, has long been known to play a crucial role in radioadaptive protection by detoxifying O2(•-) generated by mitochondrial oxidative phosphorylation. In contrast to the well-studied mechanisms of SOD2 gene regulation, the mechanisms underlying posttranslational regulation of MnSOD for radioprotection remain to be defined. Herein, we demonstrate that cyclin D1/cyclin-dependent kinase 4 (CDK4) serves as the messenger to deliver the stress signal to mitochondria to boost mitochondrial homeostasis in human skin keratinocytes under LDIR-adaptive radioprotection. Cyclin D1/CDK4 relocates to mitochondria at the same time as MnSOD enzymatic activation peaks without significant changes in total MnSOD protein level. The mitochondrial-localized CDK4 directly phosphorylates MnSOD at serine-106 (S106), causing enhanced MnSOD enzymatic activity and mitochondrial respiration. Expression of mitochondria-targeted dominant negative CDK4 or the MnSOD-S106 mutant reverses LDIR-induced mitochondrial enhancement and adaptive protection. The CDK4-mediated MnSOD activation and mitochondrial metabolism boost are also detected in skin tissues of mice receiving in vivo whole-body LDIR. These results demonstrate a unique CDK4-mediated mitochondrial communication that allows cells to sense environmental genotoxic stress and boost mitochondrial homeostasis by enhancing phosphorylation and activation of MnSOD.

  2. Mechanism of H2S-mediated protection against oxidative stress in Escherichia coli.

    PubMed

    Mironov, Alexander; Seregina, Tatyana; Nagornykh, Maxim; Luhachack, Lyly G; Korolkova, Natalya; Lopes, Liubov Errais; Kotova, Vera; Zavilgelsky, Gennady; Shakulov, Rustem; Shatalin, Konstantin; Nudler, Evgeny

    2017-06-06

    Endogenous hydrogen sulfide (H2S) renders bacteria highly resistant to oxidative stress, but its mechanism remains poorly understood. Here, we report that 3-mercaptopyruvate sulfurtransferase (3MST) is the major source of endogenous H2S in Escherichia coli Cellular resistance to H2O2 strongly depends on the activity of mstA, a gene that encodes 3MST. Deletion of the ferric uptake regulator (Fur) renders ∆mstA cells hypersensitive to H2O2 Conversely, induction of chromosomal mstA from a strong pLtetO-1 promoter (P tet -mstA) renders ∆fur cells fully resistant to H2O2 Furthermore, the endogenous level of H2S is reduced in ∆fur or ∆sodA ∆sodB cells but restored after the addition of an iron chelator dipyridyl. Using a highly sensitive reporter of the global response to DNA damage (SOS) and the TUNEL assay, we show that 3MST-derived H2S protects chromosomal DNA from oxidative damage. We also show that the induction of the CysB regulon in response to oxidative stress depends on 3MST, whereas the CysB-regulated l-cystine transporter, TcyP, plays the principle role in the 3MST-mediated generation of H2S. These findings led us to propose a model to explain the interplay between l-cysteine metabolism, H2S production, and oxidative stress, in which 3MST protects E. coli against oxidative stress via l-cysteine utilization and H2S-mediated sequestration of free iron necessary for the genotoxic Fenton reaction.

  3. B cells are not essential for Lactobacillus-mediated protection against lethal pneumovirus infection*

    PubMed Central

    Percopo, Caroline M.; Dyer, Kimberly D.; Garcia-Crespo, Katia E.; Gabryszewski, Stanislaw J.; Shaffer, Arthur L.; Domachowske, Joseph B.; Rosenberg, Helene F.

    2014-01-01

    We have shown previously that priming of respiratory mucosa with live Lactobacillus species promotes robust and prolonged survival from an otherwise lethal infection with pneumonia virus of mice (PVM), a property known as heterologous immunity. Lactobacillus-priming results in a moderate reduction in virus recovery and a dramatic reduction in virus-induced proinflammatory cytokine production; the precise mechanisms underlying these findings remain to be elucidated. As B cells have been shown to promote heterologous immunity against respiratory virus pathogens under similar conditions, here we explore the role of B cells in Lactobacillus-mediated protection against acute pneumovirus infection. We found that Lactobacillus-primed mice feature elevated levels of airway immunoglobulins IgG, IgA and IgM and lung tissues with dense, B cell (B220+) enriched peribronchial and perivascular infiltrates with germinal centers consistent with descriptions of bronchus-associated lymphoid tissue. No B cells were detected in lung tissue of Lactobacillus-primed B-cell deficient μMT mice or Jh mice, and Lactobacillus-primed μMT mice had no characteristic infiltrates or airway immunoglobulins. Nonetheless, we observed diminished virus recovery and profound suppression of virus-induced proinflammatory cytokines CCL2, IFN-gamma, and CXCL10 in both wild-type and Lactobacillus-primed μMT mice. Furthermore, L. plantarum-primed, B-cell deficient μMT and Jh mice were fully protected from an otherwise lethal PVM infection, as were their respective wild-types. We conclude that B cells are dispensable for Lactobacillus-mediated heterologous immunity and were not crucial for promoting survival in response to an otherwise lethal pneumovirus infection. PMID:24748495

  4. Myeloid HIF-1 is protective in Helicobacter pylori-mediated gastritis.

    PubMed

    Matak, Pavle; Heinis, Mylène; Mathieu, Jacques R R; Corriden, Ross; Cuvellier, Sylvain; Delga, Stéphanie; Mounier, Rémi; Rouquette, Alexandre; Raymond, Josette; Lamarque, Dominique; Emile, Jean-François; Nizet, Victor; Touati, Eliette; Peyssonnaux, Carole

    2015-04-01

    Helicobacter pylori infection triggers chronic inflammation of the gastric mucosa that may progress to gastric cancer. The hypoxia-inducible factors (HIFs) are the central mediators of cellular adaptation to low oxygen levels (hypoxia), but they have emerged recently as major transcriptional regulators of immunity and inflammation. No studies have investigated whether H. pylori affects HIF signaling in immune cells and a potential role for HIF in H. pylori-mediated gastritis. HIF-1 and HIF-2 expression was examined in human H. pylori-positive gastritis biopsies. Subsequent experiments were performed in naive and polarized bone marrow-derived macrophages from wild-type (WT) and myeloid HIF-1α-null mice (HIF-1(Δmyel)). WT and HIF-1(Δmyel) mice were inoculated with H. pylori by oral gavage and sacrificed 6 mo postinfection. HIF-1 was specifically expressed in macrophages of human H. pylori-positive gastritis biopsies. Macrophage HIF-1 strongly contributed to the induction of proinflammatory genes (IL-6, IL-1β) and inducible NO synthase in response to H. pylori. HIF-2 expression and markers of M2 macrophage differentiation were decreased in response to H. pylori. HIF-1(Δmyel) mice inoculated with H. pylori for 6 mo presented with a similar bacterial colonization than WT mice but, surprisingly, a global increase of inflammation, leading to a worsening of the gastritis, measured by an increased epithelial cell proliferation. In conclusion, myeloid HIF-1 is protective in H. pylori-mediated gastritis, pointing to the complex counterbalancing roles of innate immune and inflammatory phenotypes in driving this pathology.

  5. Unmasking of a Protective TNFR1 Mediated Signal in the Collagen Arthritis Model

    PubMed Central

    Williams-Skipp, Cheryll; Raman, Thiagarajan; Valuck, Robert J.; Watkins, Herschel; Palmer, Brent E.; Scheinman, Robert I.

    2009-01-01

    OBJECTIVE: TNFR1 plays a major role in rheumatoid arthritis (RA). Here we explore the relative importance of TNFR1 signaling in the hematopoietic tissue compartment for disease progression. METHODS: DBA/1 mice were lethally irradiated and rescued with bone marrow derived from either DBA/1 or TNFR1−/− animals. The mice were then input into the collagen induced arthritis (CIA) model and disease progression characterized. RESULTS: Surprisingly, TNFR1−/− transplant mice input into the CIA model develop increased disease as compared to controls. This could not be attributed to either an increased primary response to collagen or to the contribution of a non-DBA genetic background. Histological markers of advanced disease were evident in TNFR1−/− transplant mice shortly after initiation of the immune response to collagen and long before clinical evidence of disease. Serum TNFα was undetectable while serum IL-12p40 levels were increased in TNFR1−/− transplant mice at the end point of the study. CONCLUSION: These data raise the intriguing possibility of the existence of an anti-inflammatory TNFR1 mediated circuit in the hematopoietic compartment. This circuit bears a resemblance to emerging data delineating a switch in TNFα function observed in the resolution of bacterial infections. These data suggest that TNFR1 mediated signals in the radio-resistant tissues contributes to disease progression while TNFR1 mediated signals in the radio-sensitive tissues can contribute to protection from disease. We thus put forward the hypothesis that the degree of responce to TNFα blockade in RA is dependent, in part, on the relative genetic strengths of these two pathways. PMID:19180511

  6. Notch protection against apoptosis in T-ALL cells mediated by GIMAP5.

    PubMed

    Chadwick, Nicholas; Zeef, Leo; Portillo, Virginia; Boros, Joanna; Hoyle, Sarah; van Doesburg, Jaap C L; Buckle, Anne-Marie

    2010-10-15

    Recent studies have highlighted the role of Notch signalling in the development of T cell acute lymphoblasic leukaemia (T-ALL). Over-expression of Notch3 and gain of function mutations in the Notch1 gene have been reported. The aims of this study were to determine the effect of Notch signalling on apoptosis in human T-ALL cell lines and to identify targets of Notch signalling that may mediate this effect. Functional studies showed that inhibition of Notch signalling using gamma secretase inhibitors promoted glucocorticoid-induced apoptosis in cells carrying gain of function mutations in Notch1. Moreover, ectopic expression of constitutively activated Notch provided protection against glucocorticoid-induced apoptosis, indicating that signalling via Notch may also contribute to the development of T-ALL by conferring resistance to apoptosis. Microarray analysis revealed that GIMAP5, a gene coding for an anti-apoptotic intracellular protein, is upregulated by Notch in T-ALL cell lines. Knockdown of GIMAP5 expression using siRNA promoted glucocorticoid-induced apoptosis in T-ALL cells carrying gain of function mutations in Notch1 and in T-ALL cells engineered to express ectopic constitutively activated Notch indicating that Notch signalling protects T-ALL cells from apoptosis by upregulating the expression of GIMAP5.

  7. Protective effect of Cissus quadrangularis on neutrophil mediated tissue injury induced by aspirin in rats.

    PubMed

    Jainu, Mallika; Mohan, K Vijai; Devi, C S Shyamala

    2006-04-06

    Cissus quadrangularis (family: Vitaceae) is well known for the treatment of gastric disorders in traditional medicine, owing to its rich source of carotenoids, triterpenoids and ascorbic acid, and has received considerable attention regarding its role in human nutrition. In the search of new potential antiulcer agents, the present study evaluated the ethanol extract of Cissus quadrangularis (CQE) against the gastric toxicity induced by aspirin in rats. The optimum protective dose of 500 mg/kg of extract was selected by the pretreatment of gastric ulcers with different doses of CQE (250, 500 and 750 mg/kg) for 7 days which showed ulcer protection by 40, 71.2 and 72.6%, respectively, as compared to ranitidine (RTD) (30 mg/kg) by 71.9% in the aspirin model. In addition, results have shown that administration of aspirin increases lipid peroxidation status, xanthine oxidase (XO), myeloperoxidase and decrease in selenium-glutathione peroxidase activities in the gastric mucosa, resulting in mucosal damage at both cellular and subcellular level. Pretreatment with CQE ameliorated the observed effect significantly in the gastric mucosa of ulcerated rats. These findings suggest that the gastroprotective activity of CQE could be mediated possibly through its antioxidant effect as well as by the attenuation of the oxidative mechanism and neutrophil infiltration.

  8. MRG15-mediated tethering of PALB2 to unperturbed chromatin protects active genes from genotoxic stress

    PubMed Central

    Bleuyard, Jean-Yves; Fournier, Marjorie; Nakato, Ryuichiro; Couturier, Anthony M.; Katou, Yuki; Ralf, Christine; Hester, Svenja S.; Dominguez, Daniel; Rhodes, Daniela; Humphrey, Timothy C.; Shirahige, Katsuhiko

    2017-01-01

    The partner and localiser of BRCA2 (PALB2) plays important roles in the maintenance of genome integrity and protection against cancer. Although PALB2 is commonly described as a repair factor recruited to sites of DNA breaks, recent studies provide evidence that PALB2 also associates with unperturbed chromatin. Here, we investigated the previously poorly described role of chromatin-associated PALB2 in undamaged cells. We found that PALB2 associates with active genes through its major binding partner, MRG15, which recognizes histone H3 trimethylated at lysine 36 (H3K36me3) by the SETD2 methyltransferase. Missense mutations that ablate PALB2 binding to MRG15 confer elevated sensitivity to the topoisomerase inhibitor camptothecin (CPT) and increased levels of aberrant metaphase chromosomes and DNA stress in gene bodies, which were suppressed by preventing DNA replication. Remarkably, the level of PALB2 at genic regions was frequently decreased, rather than increased, upon CPT treatment. We propose that the steady-state presence of PALB2 at active genes, mediated through the SETD2/H3K36me3/MRG15 axis, ensures an immediate response to DNA stress and therefore effective protection of these regions during DNA replication. This study provides a conceptual advance in demonstrating that the constitutive chromatin association of repair factors plays a key role in the maintenance of genome stability and furthers our understanding of why PALB2 defects lead to human genome instability syndromes. PMID:28673974

  9. CXCR5⁺ T helper cells mediate protective immunity against tuberculosis.

    PubMed

    Slight, Samantha R; Rangel-Moreno, Javier; Gopal, Radha; Lin, Yinyao; Fallert Junecko, Beth A; Mehra, Smriti; Selman, Moises; Becerril-Villanueva, Enrique; Baquera-Heredia, Javier; Pavon, Lenin; Kaushal, Deepak; Reinhart, Todd A; Randall, Troy D; Khader, Shabaana A

    2013-02-01

    One third of the world's population is infected with Mycobacterium tuberculosis (Mtb). Although most infected people remain asymptomatic, they have a 10% lifetime risk of developing active tuberculosis (TB). Thus, the current challenge is to identify immune parameters that distinguish individuals with latent TB from those with active TB. Using human and experimental models of Mtb infection, we demonstrated that organized ectopic lymphoid structures containing CXCR5+ T cells were present in Mtb-infected lungs. In addition, we found that in experimental Mtb infection models, the presence of CXCR5+ T cells within ectopic lymphoid structures was associated with immune control. Furthermore, in a mouse model of Mtb infection, we showed that activated CD4+CXCR5+ T cells accumulated in Mtb-infected lungs and produced proinflammatory cytokines. Mice deficient in Cxcr5 had increased susceptibility to TB due to defective T cell localization within the lung parenchyma. We demonstrated that CXCR5 expression in T cells mediated correct T cell localization within TB granulomas, promoted efficient macrophage activation, protected against Mtb infection, and facilitated lymphoid follicle formation. These data demonstrate that CD4+CXCR5+ T cells play a protective role in the immune response against TB and highlight their potential use for future TB vaccine design and therapy.

  10. Tie-mediated signal from apoptotic cells protects stem cells in Drosophila melanogaster

    PubMed Central

    Xing, Yalan; Su, Tin Tin; Ruohola-Baker, Hannele

    2015-01-01

    Many types of normal and cancer stem cells are resistant to killing by genotoxins, but the mechanism for this resistance is poorly understood. Here we show that adult stem cells in Drosophila melanogaster germline and midgut are resistant to ionizing radiation (IR) or chemically induced apoptosis and dissect the mechanism for this protection. We find that upon IR the receptor tyrosine kinase Tie/Tie-2 is activated, leading to the upregulation of microRNA bantam that represses FOXO-mediated transcription of pro-apoptotic Smac/DIA-BLO orthologue, Hid in germline stem cells. Knockdown of the IR-induced putative Tie ligand, Pvf1, a functional homologue of human Angiopoietin, in differentiating daughter cells renders germline stem cells sensitive to IR, suggesting that the dying daughters send a survival signal to protect their stem cells for future repopulation of the tissue. If conserved in cancer stem cells, this mechanism may provide therapeutic options for the eradication of cancer. PMID:25959206

  11. Oxygen radical-mediated injury of myocytes-protection by propranolol.

    PubMed

    Mak, I T; Kramer, J H; Freedman, A M; Tse, S Y; Weglicki, W B

    1990-06-01

    UIe effects of propranolol and atenolol on free radical mediated injury in myocytes were examined. Freshly isolated adult canine myocytes were incubated with a superoxide generating (from dihydroxyfumarate) and Fe-catalyzed free radical system. Exposure of the myocytes to free radicals for 20 min resulted in more than a 5-fold increase in thiobarbituric acid reactant (peroxide) formation and elevated levels of lactate dehydrogenase (LDH) activity released into the media compared to controls. Ultrastructurally, severe sarcolemmal damage, mitochondrial and myofibril derangements were evident. At 40 min, cellular viability (trypan blue exclusion) in the samples exposed to free radicals decreased to about one-third of controls; concomitantly, major losses in total cellular phospholipids occurred. When the cells were pretreated with 200 microM propranolol before the addition of free radicals, both peroxide formation and increased LDH release were inhibited; in agreement, complete ultrastructural preservation was observed. In addition, the subsequent losses in cellular viability and phospholipids were prevented. For comparison, the more water soluble beta-blocker, atenolol at 200 microM was shown ineffective in providing significant protection against the induced injury. The results suggest that propranolol may provide antiperoxidative protection to myocytes when elevated levels of free radicals are present.

  12. The transrepression arm of glucocorticoid receptor signaling is protective in mutant huntingtin-mediated neurodegeneration

    PubMed Central

    Varadarajan, S; Breda, C; Smalley, J L; Butterworth, M; Farrow, S N; Giorgini, F; Cohen, G M

    2015-01-01

    The unfolded protein response (UPR) occurs following the accumulation of unfolded proteins in the endoplasmic reticulum (ER) and orchestrates an intricate balance between its prosurvival and apoptotic arms to restore cellular homeostasis and integrity. However, in certain neurodegenerative diseases, the apoptotic arm of the UPR is enhanced, resulting in excessive neuronal cell death and disease progression, both of which can be overcome by modulating the UPR. Here, we describe a novel crosstalk between glucocorticoid receptor signaling and the apoptotic arm of the UPR, thus highlighting the potential of glucocorticoid therapy in treating neurodegenerative diseases. Several glucocorticoids, but not mineralocorticoids, selectively antagonize ER stress-induced apoptosis in a manner that is downstream of and/or independent of the conventional UPR pathways. Using GRT10, a novel selective pharmacological modulator of glucocorticoid signaling, we describe the importance of the transrepression arm of the glucocorticoid signaling pathway in protection against ER stress-induced apoptosis. Furthermore, we also observe the protective effects of glucocorticoids in vivo in a Drosophila model of Huntington's disease (HD), wherein treatment with different glucocorticoids diminished rhabdomere loss and conferred neuroprotection. Finally, we find that growth differentiation factor 15 has an important role downstream of glucocorticoid signaling in antagonizing ER stress-induced apoptosis in cells, as well as in preventing HD-mediated neurodegeneration in flies. Thus, our studies demonstrate that this novel crosstalk has the potential to be effectively exploited in alleviating several neurodegenerative disorders. PMID:25656655

  13. Resveratrol Protects Against Pathological Preterm Birth by Suppression of Macrophage-Mediated Inflammation.

    PubMed

    Furuya, Hitomi; Taguchi, Ayumi; Kawana, Kei; Yamashita, Aki; Inoue, Eri; Yoshida, Mitsuyo; Nakamura, Hiroe; Fujimoto, Asaha; Inoue, Tomoko; Sato, Masakazu; Nishida, Haruka; Nagasaka, Kazunori; Adachi, Katsuyuki; Hoya, Mari; Nagamatsu, Takeshi; Wada-Hiraike, Osamu; Yamashita, Takahiro; Osuga, Yutaka; Fujii, Tomoyuki

    2015-12-01

    Inflammatory cytokines play a major role in spontaneous preterm birth. Resveratrol has strong anti-inflammatory effects, but its effect on preterm birth in vivo is unknown. We investigated whether resveratrol protects against preterm birth in the lipopolysaccharide (LPS)-induced preterm mouse model. Twelve-day-old pregnant mice were fed 20 to 40 mg/kg resveratrol daily. On day 15, 10 μg of LPS was injected into uterine cervices. Resveratrol administration significantly decreased the rate of preterm birth. Resveratrol administration abolished LPS-induced elevation of tumor necrosis factor α (TNF-α) and interleukin (IL) 1β but not IL-6 levels. The TNF-α messenger RNA levels were decreased in the cervices of resveratrol-administered mice compared with controls. Resveratrol treatment suppressed the elevation in TNF-α and IL-1β levels in LPS-exposed peritoneal macrophages. Further resveratrol treatment eradicated the proinflammatory cytokine-mediated elevation in cyclooxygenase 2 (COX-2) in peritoneal macrophages. Resveratrol may protect against pathological preterm birth by suppression of elevated proinflammatory cytokines and consequent elevation of COX-2 in macrophages.

  14. Erythropoietin-mediated protection in kidney transplantation: nonerythropoietic EPO derivatives improve function without increasing risk of cardiovascular events.

    PubMed

    van Rijt, Willem G; van Goor, Harry; Ploeg, Rutger J; Leuvenink, Henri G D

    2014-03-01

    The protective, nonerythropoietic effects of erythropoietin (EPO) have become evident in preclinical models in renal ischaemia/reperfusion injury and kidney transplantation. However, four recently published clinical trials using high-dose EPO treatment following renal transplantation did not reveal any protective effect for short-term renal function and even reported an increased risk of thrombosis. This review focusses on the current status of protective pathways mediated by EPO, the safety concerns using high EPO dosage and discusses the discrepancies between pre-clinical and clinical studies. The protective effects are mediated by binding of EPO to a heteromeric receptor complex consisting of two β-common receptors and two EPO receptors. An important role for the activation of endothelial nitric oxide synthase is proposed. EPO-mediated cytoprotection still has enormous potential. However, only nonerythropoietic EPO derivatives may induce protection without increasing the risk of cardiovascular events. In preclinical models, nonerythropoietic EPO derivatives, such as carbamoylated EPO and ARA290, have been tested. These EPO derivatives improve renal function and do not affect erythropoiesis. Therefore, nonerythropoietic EPO derivatives may be able to render EPO-mediated cytoprotection useful and beneficial for clinical transplantation.

  15. Interferon Control of the Sterol Metabolic Network: Bidirectional Molecular Circuitry-Mediating Host Protection

    PubMed Central

    Robertson, Kevin A.; Ghazal, Peter

    2016-01-01

    The sterol metabolic network is emerging center stage in inflammation and immunity. Historically, observational clinical studies show that hypocholesterolemia is a common side effect of interferon (IFN) treatment. More recently, comprehensive systems-wide investigations of the macrophage IFN response reveal a direct molecular link between cholesterol metabolism and infection. Upon infection, flux through the sterol metabolic network is acutely moderated by the IFN response at multiple regulatory levels. The precise mechanisms by which IFN regulates the mevalonate-sterol pathway—the spine of the network—are beginning to be unraveled. In this review, we discuss our current understanding of the multifactorial mechanisms by which IFN regulates the sterol pathway. We also consider bidirectional communications resulting in sterol metabolism regulation of immunity. Finally, we deliberate on how this fundamental interaction functions as an integral element of host protective responses to infection and harmful inflammation. PMID:28066443

  16. Interferon Control of the Sterol Metabolic Network: Bidirectional Molecular Circuitry-Mediating Host Protection.

    PubMed

    Robertson, Kevin A; Ghazal, Peter

    2016-01-01

    The sterol metabolic network is emerging center stage in inflammation and immunity. Historically, observational clinical studies show that hypocholesterolemia is a common side effect of interferon (IFN) treatment. More recently, comprehensive systems-wide investigations of the macrophage IFN response reveal a direct molecular link between cholesterol metabolism and infection. Upon infection, flux through the sterol metabolic network is acutely moderated by the IFN response at multiple regulatory levels. The precise mechanisms by which IFN regulates the mevalonate-sterol pathway-the spine of the network-are beginning to be unraveled. In this review, we discuss our current understanding of the multifactorial mechanisms by which IFN regulates the sterol pathway. We also consider bidirectional communications resulting in sterol metabolism regulation of immunity. Finally, we deliberate on how this fundamental interaction functions as an integral element of host protective responses to infection and harmful inflammation.

  17. Digoxin-Mediated Upregulation of RGS2 Protein Protects against Cardiac Injury.

    PubMed

    Sjögren, Benita; Parra, Sergio; Atkins, Kevin B; Karaj, Behirda; Neubig, Richard R

    2016-05-01

    Regulator of G protein signaling (RGS) proteins have emerged as novel drug targets since their discovery almost two decades ago. RGS2 has received particular interest in cardiovascular research due to its role in regulating Gqsignaling in the heart and vascular smooth muscle. RGS2(-/-)mice are hypertensive, prone to heart failure, and display accelerated kidney fibrosis. RGS2 is rapidly degraded through the proteasome, and human mutations leading to accelerated RGS2 protein degradation correlate with hypertension. Hence, stabilizing RGS2 protein expression could be a novel route in treating cardiovascular disease. We previously identified cardiotonic steroids, including digoxin, as selective stabilizers of RGS2 protein in vitro. In the current study we investigated the functional effects of digoxin-mediated RGS2 protein stabilization in vivo. Using freshly isolated myocytes from wild-type and RGS2(-/-)mice treated with vehicle or low-dose digoxin (2µg/kg/day for 7 days) we demonstrated that agonist-induced cAMP levels and cardiomyocyte contractility was inhibited by digoxin in wild-type but not in RGS2(-/-)mice. This inhibition was accompanied by an increase in RGS2 protein levels in cardiomyocytes as well as in whole heart tissue. Furthermore, digoxin had protective effects in a model of cardiac injury in wild-type mice and this protection was lost in RGS2(-/-)mice. Digoxin is the oldest known therapy for heart failure; however, beyond its activity at the Na(+)/K(+)-ATPase, the exact mechanism of action is not known. The current study adds a novel mechanism, whereby through stabilizing RGS2 protein levels digoxin could exert its protective effects in the failing heart.

  18. Immune cell-mediated protection of the mammary gland and the infant during breastfeeding.

    PubMed

    Hassiotou, Foteini; Geddes, Donna T

    2015-05-01

    Breastfeeding has been regarded first and foremost as a means of nutrition for infants, providing essential components for their unique growth and developmental requirements. However, breast milk is also rich in immunologic factors, highlighting its importance as a mediator of protection. In accordance with its evolutionary origin, the mammary gland offers via the breastfeeding route continuation of the maternal to infant immunologic support established in utero. At birth, the infant's immune system is immature, and although it was exposed to the maternal microbial flora during pregnancy, it experiences an abrupt change in its microbial environment during and after birth, which is challenging and renders the infant highly susceptible to infection. Active and passive immunity protects the infant via breast milk, which is rich in immunoglobulins, lactoferrin, lysozyme, cytokines, and numerous other immunologic factors, including maternal leukocytes. Breast milk leukocytes provide active immunity and promote development of immunocompetence in the infant. Additionally, it has been speculated that they play a role in the protection of the mammary gland from infection. Leukocytes are thought to exert these functions via phagocytosis, secretion of antimicrobial factors and/or antigen presentation in both the mammary gland and the gastrointestinal tract of the infant, and also in other infant tissues, where they are transported via the systemic circulation. Recently, it has been demonstrated that breast milk leukocytes respond dynamically to maternal as well as infant infections, and are fewer in nonexclusively compared with exclusively breastfeeding dyads, further emphasizing their importance for both the mother and infant. This review summarizes the current knowledge of human milk leukocytes and factors influencing them, and presents recent novel findings supporting their potential as a diagnostic marker for infections of the lactating breast and of the breastfed infant.

  19. Zeaxanthin induces Nrf2-mediated phase II enzymes in protection of cell death

    PubMed Central

    Zou, X; Gao, J; Zheng, Y; Wang, X; Chen, C; Cao, K; Xu, J; Li, Y; Lu, W; Liu, J; Feng, Z

    2014-01-01

    Zeaxanthin (Zea) is a major carotenoid pigment contained in human retina, and its daily supplementation associated with lower risk of age-related macular degeneration. Despite known property of Zea as an antioxidant, its underlying molecular mechanisms of action remain poorly understood. In this study, we aim to study the regulation mechanism of Zea on phase II detoxification enzymes. In normal human retinal pigment epithelium cells, Zea promoted the nuclear translocation of NF-E2-related factor 2 (Nrf2) and induced mRNA and protein expression of phase II enzymes, the induction was suppressed by specific knockdown of Nrf2. Zea also effectively protected against tert-butyl hydroperoxide-induced mitochondrial dysfunction and apoptosis. Glutathione (GSH) as the most important antioxidant was also induced by Zea through Nrf2 activation in a time- and dose-dependent manner, whereas the protective effects of Zea were decimated by inhibition of GSH synthesis. Finally, Zea activated the PI3K/Akt and MAPK/ERK pathway, whereas only PI3K/Akt activation correlated with phase II enzymes induction and Zea protection. In further in vivo analyses, Zea showed effects of inducing phase II enzymes and increased GSH content, which contributed to the reduced lipid and protein peroxidation in the retina as well as the liver, heart, and serum of the Sprague–Dawley rats. For the first time, Zea is presented as a phase II enzymes inducer instead of being an antioxidant. By activating Nrf2-mediated phase II enzymes, Zea could enhance anti-oxidative capacity and prevent cell death both in vivo and in vitro. PMID:24810054

  20. Immune Cell–Mediated Protection of the Mammary Gland and the Infant during Breastfeeding1234

    PubMed Central

    Hassiotou, Foteini; Geddes, Donna T

    2015-01-01

    Breastfeeding has been regarded first and foremost as a means of nutrition for infants, providing essential components for their unique growth and developmental requirements. However, breast milk is also rich in immunologic factors, highlighting its importance as a mediator of protection. In accordance with its evolutionary origin, the mammary gland offers via the breastfeeding route continuation of the maternal to infant immunologic support established in utero. At birth, the infant’s immune system is immature, and although it was exposed to the maternal microbial flora during pregnancy, it experiences an abrupt change in its microbial environment during and after birth, which is challenging and renders the infant highly susceptible to infection. Active and passive immunity protects the infant via breast milk, which is rich in immunoglobulins, lactoferrin, lysozyme, cytokines, and numerous other immunologic factors, including maternal leukocytes. Breast milk leukocytes provide active immunity and promote development of immunocompetence in the infant. Additionally, it has been speculated that they play a role in the protection of the mammary gland from infection. Leukocytes are thought to exert these functions via phagocytosis, secretion of antimicrobial factors and/or antigen presentation in both the mammary gland and the gastrointestinal tract of the infant, and also in other infant tissues, where they are transported via the systemic circulation. Recently, it has been demonstrated that breast milk leukocytes respond dynamically to maternal as well as infant infections, and are fewer in nonexclusively compared with exclusively breastfeeding dyads, further emphasizing their importance for both the mother and infant. This review summarizes the current knowledge of human milk leukocytes and factors influencing them, and presents recent novel findings supporting their potential as a diagnostic marker for infections of the lactating breast and of the breastfed

  1. Digoxin-Mediated Upregulation of RGS2 Protein Protects against Cardiac Injury

    PubMed Central

    Parra, Sergio; Atkins, Kevin B.; Karaj, Behirda; Neubig, Richard R.

    2016-01-01

    Regulator of G protein signaling (RGS) proteins have emerged as novel drug targets since their discovery almost two decades ago. RGS2 has received particular interest in cardiovascular research due to its role in regulating Gq signaling in the heart and vascular smooth muscle. RGS2−/− mice are hypertensive, prone to heart failure, and display accelerated kidney fibrosis. RGS2 is rapidly degraded through the proteasome, and human mutations leading to accelerated RGS2 protein degradation correlate with hypertension. Hence, stabilizing RGS2 protein expression could be a novel route in treating cardiovascular disease. We previously identified cardiotonic steroids, including digoxin, as selective stabilizers of RGS2 protein in vitro. In the current study we investigated the functional effects of digoxin-mediated RGS2 protein stabilization in vivo. Using freshly isolated myocytes from wild-type and RGS2−/− mice treated with vehicle or low-dose digoxin (2 µg/kg/day for 7 days) we demonstrated that agonist-induced cAMP levels and cardiomyocyte contractility was inhibited by digoxin in wild-type but not in RGS2−/− mice. This inhibition was accompanied by an increase in RGS2 protein levels in cardiomyocytes as well as in whole heart tissue. Furthermore, digoxin had protective effects in a model of cardiac injury in wild-type mice and this protection was lost in RGS2−/− mice. Digoxin is the oldest known therapy for heart failure; however, beyond its activity at the Na+/K+-ATPase, the exact mechanism of action is not known. The current study adds a novel mechanism, whereby through stabilizing RGS2 protein levels digoxin could exert its protective effects in the failing heart. PMID:26941169

  2. The exopolysaccharide alginate protects Pseudomonas aeruginosa biofilm bacteria from IFN-gamma-mediated macrophage killing.

    PubMed

    Leid, Jeff G; Willson, Carey J; Shirtliff, Mark E; Hassett, Daniel J; Parsek, Matthew R; Jeffers, Alyssa K

    2005-12-01

    The ability of Pseudomonas aeruginosa to form biofilms and cause chronic infections in the lungs of cystic fibrosis patients is well documented. Numerous studies have revealed that P. aeruginosa biofilms are highly refractory to antibiotics. However, dramatically fewer studies have addressed P. aeruginosa biofilm resistance to the host's immune system. In planktonic, unattached (nonbiofilm) P. aeruginosa, the exopolysaccharide alginate provides protection against a variety of host factors yet the role of alginate in protection of biofilm bacteria is unclear. To address this issue, we tested wild-type strains PAO1, PA14, the mucoid cystic fibrosis isolate, FRD1 (mucA22+), and the respective isogenic mutants which lacked the ability to produce alginate, for their susceptibility to human leukocytes in the presence and absence of IFN-gamma. Human leukocytes, in the presence of recombinant human IFN-gamma, killed biofilm bacteria lacking alginate after a 4-h challenge at 37 degrees C. Bacterial killing was dependent on the presence of IFN-gamma. Killing of the alginate-negative biofilm bacteria was mediated through mononuclear cell phagocytosis since treatment with cytochalasin B, which prevents actin polymerization, inhibited leukocyte-specific bacterial killing. By direct microscopic observation, phagocytosis of alginate-negative biofilm bacteria was significantly increased in the presence of IFN-gamma vs all other treatments. Addition of exogenous, purified alginate to the alginate-negative biofilms restored resistance to human leukocyte killing. Our results suggest that although alginate may not play a significant role in bacterial attachment, biofilm development, and formation, it may play an important role in protecting mucoid P. aeruginosa biofilm bacteria from the human immune system.

  3. Using hierarchical linear growth models to evaluate protective mechanisms that mediate science achievement

    NASA Astrophysics Data System (ADS)

    von Secker, Clare Elaine

    The study of students at risk is a major topic of science education policy and discussion. Much research has focused on describing conditions and problems associated with the statistical risk of low science achievement among individuals who are members of groups characterized by problems such as poverty and social disadvantage. But outcomes attributed to these factors do not explain the nature and extent of mechanisms that account for differences in performance among individuals at risk. There is ample theoretical and empirical evidence that demographic differences should be conceptualized as social contexts, or collections of variables, that alter the psychological significance and social demands of life events, and affect subsequent relationships between risk and resilience. The hierarchical linear growth models used in this dissertation provide greater specification of the role of social context and the protective effects of attitude, expectations, parenting practices, peer influences, and learning opportunities on science achievement. While the individual influences of these protective factors on science achievement were small, their cumulative effect was substantial. Meta-analysis conducted on the effects associated with psychological and environmental processes that mediate risk mechanisms in sixteen social contexts revealed twenty-two significant differences between groups of students. Positive attitudes, high expectations, and more intense science course-taking had positive effects on achievement of all students, although these factors were not equally protective in all social contexts. In general, effects associated with authoritative parenting and peer influences were negative, regardless of social context. An evaluation comparing the performance and stability of hierarchical linear growth models with traditional repeated measures models is included as well.

  4. Protection of orbital station optics against high-speed damaging elements

    NASA Astrophysics Data System (ADS)

    Merkulov, Yu. Yu.; Solk, S. V.; Lebedev, O. A.

    2017-06-01

    Various protection of optical devices, arranged in the orbital stations against "space debris" and probable terrorist acts in space are examined in the paper. The materials, transparent in visible spectrum and applied for development of transparent armor, are given. Variants and prospects for creation of new materials intended to protect optical devices in space are considered.

  5. Gang Membership, School Violence, and the Mediating Effects of Risk and Protective Behaviors in California High Schools

    ERIC Educational Resources Information Center

    Estrada, Joey Nuñez, Jr.; Gilreath, Tamika D.; Astor, Ron Avi; Benbenishty, Rami

    2014-01-01

    There is insufficient empirical evidence exploring associations between gang membership and school violence behaviors. Using a sample of 272,863 high school students, this study employs a structural equation model to examine how school risk and protective behaviors and attitudes mediate effects of gang members' involvement with school violence…

  6. Gang Membership, School Violence, and the Mediating Effects of Risk and Protective Behaviors in California High Schools

    ERIC Educational Resources Information Center

    Estrada, Joey Nuñez, Jr.; Gilreath, Tamika D.; Astor, Ron Avi; Benbenishty, Rami

    2014-01-01

    There is insufficient empirical evidence exploring associations between gang membership and school violence behaviors. Using a sample of 272,863 high school students, this study employs a structural equation model to examine how school risk and protective behaviors and attitudes mediate effects of gang members' involvement with school violence…

  7. Mediation of improvements in sun protective and skin self-examination behaviours: results from the healthy text study.

    PubMed

    Baker, Jannah; Finch, Linda; Soyer, H Peter; Marshall, Alison L; Baade, Peter; Youl, Philippa; Janda, Monika

    2016-01-01

    Melanoma is on the rise, especially in Caucasian populations exposed to high ultraviolet radiation such as in Australia. This paper examined the psychological components facilitating change in skin cancer prevention or early detection behaviours following a text message intervention. The Queensland-based participants were 18 to 42 years old, from the Healthy Text study (N = 546). Overall, 512 (94%) participants completed the 12-month follow-up questionnaires. Following the social cognitive model, potential mediators of skin self-examination (SSE) and sun protection behaviour change were examined using stepwise logistic regression models. At 12-month follow-up, odds of performing an SSE in the past 12 months were mediated by baseline confidence in finding time to check skin (an outcome expectation), with a change in odds ratio of 11.9% in the SSE group versus the control group when including the mediator. Odds of greater than average sun protective habits index at 12-month follow-up were mediated by (a) an attempt to get a suntan at baseline (an outcome expectation) and (b) baseline sun protective habits index, with a change in odds ratio of 10.0% and 11.8%, respectively in the SSE group versus the control group. Few of the suspected mediation pathways were confirmed with the exception of outcome expectations and past behaviours. Future intervention programmes could use alternative theoretical models to elucidate how improvements in health behaviours can optimally be facilitated. Copyright © 2015 John Wiley & Sons, Ltd.

  8. The Effect of Selected Cinemagraphic Elements on Audience Perception of Mediated Concepts.

    ERIC Educational Resources Information Center

    Orr, Quinn

    This study is to explore cinemagraphic and visual elements and their inter-relations through the reinterpretation of previous research and literature. The cinemagraphic elements of visual images (camera angle, camera motion, subject motion, color, and lighting) work as a language requiring a proper grammar for the messages to be conveyed in their…

  9. Inhibition of Cx43 mediates protective effects on hypoxic/reoxygenated human neuroblastoma cells.

    PubMed

    Vicario, Nunzio; Calabrese, Giovanna; Zappalà, Agata; Parenti, Carmela; Forte, Stefano; Graziano, Adriana Carol Eleonora; Vanella, Luca; Pellitteri, Rosalia; Cardile, Venera; Parenti, Rosalba

    2017-10-01

    Olfactory ensheathing cells (OECs), a special population of glial cells, are able to synthesise several trophic factors exerting a neuroprotective action and promoting growth and functional recovery in both in vitro and in vivo models. In the present work, we investigated the neuroprotective effects of OEC-conditioned medium (OEC-CM) on two different human neuron-like cell lines, SH-SY5Y and SK-N-SH (neuroblastoma cell lines), under normoxic and hypoxic conditions. In addition, we also focused our attention on the role of connexins (Cxs) in the neuroprotective processes. Our results confirmed OEC-CM mediated neuroprotection as shown by cell adherence, proliferation and cellular viability analyses. Reduced connexin 43 (Cx43) levels in OEC-CM compared to unconditioned cells in hypoxic conditions prompted us to investigate the role of Cx43-Gap junctions (GJs) and Cx43-hemichannels (HCs) in hypoxic/reoxygenation injury using carbenoxolone (non-selective GJ inhibitor), ioxynil octanoato (selective Cx43-GJ inhibitor) and Gap19 (selective Cx43-HC inhibitor). We found that Cx43-GJ and Cx43-HC inhibitors are able to protect SH-SY5Y and allow to these cultures to overcome the injury. Our findings support the hypothesis that both OEC-CM and the inhibition of Cx43-GJs and Cx43-HCs offer a neuroprotective effect by reducing Cx43-mediated cell-to-cell and cell-to-extracellular environment communications. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  10. Antiviral Protection via RdRP-Mediated Stable Activation of Innate Immunity

    PubMed Central

    Painter, Meghan M.; Morrison, James H.; Zoecklein, Laurie J.; Rinkoski, Tommy A.; Watzlawik, Jens O.; Papke, Louisa M.; Warrington, Arthur E.; Bieber, Allan J.; Matchett, William E.; Turkowski, Kari L.; Poeschla, Eric M.; Rodriguez, Moses

    2015-01-01

    For many emerging and re-emerging infectious diseases, definitive solutions via sterilizing adaptive immunity may require years or decades to develop, if they are even possible. The innate immune system offers alternative mechanisms that do not require antigen-specific recognition or a priori knowledge of the causative agent. However, it is unclear whether effective stable innate immune system activation can be achieved without triggering harmful autoimmunity or other chronic inflammatory sequelae. Here, we show that transgenic expression of a picornavirus RNA-dependent RNA polymerase (RdRP), in the absence of other viral proteins, can profoundly reconfigure mammalian innate antiviral immunity by exposing the normally membrane-sequestered RdRP activity to sustained innate immune detection. RdRP-transgenic mice have life-long, quantitatively dramatic upregulation of 80 interferon-stimulated genes (ISGs) and show profound resistance to normally lethal viral challenge. Multiple crosses with defined knockout mice (Rag1, Mda5, Mavs, Ifnar1, Ifngr1, and Tlr3) established that the mechanism operates via MDA5 and MAVS and is fully independent of the adaptive immune system. Human cell models recapitulated the key features with striking fidelity, with the RdRP inducing an analogous ISG network and a strict block to HIV-1 infection. This RdRP-mediated antiviral mechanism does not depend on secondary structure within the RdRP mRNA but operates at the protein level and requires RdRP catalysis. Importantly, despite lifelong massive ISG elevations, RdRP mice are entirely healthy, with normal longevity. Our data reveal that a powerfully augmented MDA5-mediated activation state can be a well-tolerated mammalian innate immune system configuration. These results provide a foundation for augmenting innate immunity to achieve broad-spectrum antiviral protection. PMID:26633895

  11. C1 inhibitor-mediated myocardial protection from chronic intermittent hypoxia-induced injury

    PubMed Central

    Fu, Jinrong; Guo, Furong; Chen, Cheng; Yu, Xiaoman; Hu, Ke; Li, Mingjiang

    2016-01-01

    The optimal treatment for chronic intermittent hypoxia (CIH)-induced cardiovascular injuries has yet to be determined. The aim of the current study was to explore the potential protective effect and mechanism of a C1 inhibitor in CIH in the myocardium. The present study used a rat model of CIH in which complement regulatory protein, known as C1 inhibitor (C1INH), was administered to the rats in the intervention groups. Cardiomyocyte apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling. The expression of proteins associated with the apoptotic pathway, such as B-cell lymphoma 2 (Bcl-2), Bax and caspase-3 were detected by western blot analysis. The expression of complement C3 protein and RNA were also analyzed. C1INH was observed to improve the cardiac function in rats with CIH. Myocardial myeloperoxidase activity, a marker of neutrophil infiltration, was significantly decreased in the C1INH intervention group compared with the CIH control group, and cardiomyocyte apoptosis was significantly attenuated (P<0.05). Western blotting and reverse transcription-polymerase chain reaction analysis indicated that the protein expression levels of Bcl-2 were decreased and those of Bax were increased in the CIH group compared with the normal control group, but the protein expression levels of Bcl-2 were increased and those of Bax were decreased in the C1INH intervention group, as compared with the CIH group. Furthermore, the CIH-induced expression and synthesis of complement C3 in the myocardium were also reduced in the C1INH intervention group. C1INH, in addition to inhibiting complement activation and inflammation, preserved cardiac function in CIH-mediated myocardial cell injury through an anti-apoptotic mechanism. PMID:27698713

  12. Antiviral Protection via RdRP-Mediated Stable Activation of Innate Immunity.

    PubMed

    Painter, Meghan M; Morrison, James H; Zoecklein, Laurie J; Rinkoski, Tommy A; Watzlawik, Jens O; Papke, Louisa M; Warrington, Arthur E; Bieber, Allan J; Matchett, William E; Turkowski, Kari L; Poeschla, Eric M; Rodriguez, Moses

    2015-12-01

    For many emerging and re-emerging infectious diseases, definitive solutions via sterilizing adaptive immunity may require years or decades to develop, if they are even possible. The innate immune system offers alternative mechanisms that do not require antigen-specific recognition or a priori knowledge of the causative agent. However, it is unclear whether effective stable innate immune system activation can be achieved without triggering harmful autoimmunity or other chronic inflammatory sequelae. Here, we show that transgenic expression of a picornavirus RNA-dependent RNA polymerase (RdRP), in the absence of other viral proteins, can profoundly reconfigure mammalian innate antiviral immunity by exposing the normally membrane-sequestered RdRP activity to sustained innate immune detection. RdRP-transgenic mice have life-long, quantitatively dramatic upregulation of 80 interferon-stimulated genes (ISGs) and show profound resistance to normally lethal viral challenge. Multiple crosses with defined knockout mice (Rag1, Mda5, Mavs, Ifnar1, Ifngr1, and Tlr3) established that the mechanism operates via MDA5 and MAVS and is fully independent of the adaptive immune system. Human cell models recapitulated the key features with striking fidelity, with the RdRP inducing an analogous ISG network and a strict block to HIV-1 infection. This RdRP-mediated antiviral mechanism does not depend on secondary structure within the RdRP mRNA but operates at the protein level and requires RdRP catalysis. Importantly, despite lifelong massive ISG elevations, RdRP mice are entirely healthy, with normal longevity. Our data reveal that a powerfully augmented MDA5-mediated activation state can be a well-tolerated mammalian innate immune system configuration. These results provide a foundation for augmenting innate immunity to achieve broad-spectrum antiviral protection.

  13. A reappraisal of humoral immunity based on mechanisms of antibody-mediated protection against intracellular pathogens.

    PubMed

    Casadevall, Arturo; Pirofski, Liise-anne

    2006-01-01

    Sometime in the mid to late twentieth century the study of antibody-mediated immunity (AMI) entered the doldrums, as many immunologists believed that the function of AMI was well understood, and was no longer deserving of intensive investigation. However, beginning in the 1990s studies using monoclonal antibodies (mAbs) revealed new functions for antibodies, including direct antimicrobial effects and their ability to modify host inflammatory and cellular responses. Furthermore, the demonstration that mAbs to several intracellular bacterial and fungal pathogens were protective issued a serious challenge to the paradigm that host defense against such microbes was strictly governed by cell-mediated immunity (CMI). Hence, a new view of AMI is emerging. This view is based on the concept that a major function of antibody (Ab) is to amplify or subdue the inflammatory response to a microbe. In this regard, the "damage-response framework" of microbial pathogenesis provides a new conceptual viewpoint for understanding mechanisms of AMI. According to this view, the ability of an Ab to affect the outcome of a host-microbe interaction is a function of its capacity to modify the damage ensuing from such an interaction. In fact, it is increasingly apparent that the efficacy of an Ab cannot be defined either by immunoglobulin or epitope characteristics alone, but rather by a complex function of Ab variables, such as specificity, isotype, and amount, host variables, such as genetic background and immune status, and microbial variables, such as inoculum, mechanisms of avoiding host immune surveillance and pathogenic strategy. Consequently, far from being understood, recent findings in AMI imply a system with unfathomable complexity and the field is poised for a long overdue renaissance.

  14. Cyclic adenosine monophosphate-mediated protection against bile acid-induced apoptosis in cultured rat hepatocytes.

    PubMed

    Webster, C R; Anwer, M S

    1998-05-01

    Cyclic adenosine monophosphate (cAMP) has been shown to modulate apoptosis. To evaluate the role of cAMP in bile acid-induced hepatocyte apoptosis, we studied the effect of agents that increase cAMP on the induction of apoptosis by glycochenodeoxycholate (GCDC) in cultured rat hepatocytes. GCDC induced apoptosis in 26.5%+/-1.1% of hepatocytes within 2 hours. Twenty-minute pretreatment of hepatocytes with 100 micromol/L 8-(4-chlorothiophenyl) cAMP (CP-cAMP) resulted in a reduction in the amount of apoptosis to 35.2%+/-3.8% of that seen in hepatocytes treated with GCDC alone. Other agents that increase intracellular cAMP, including dibutyryl cAMP (100 micromol/L), glucagon (200 nmol/L), and a combination of forskolin (20 micromol/L) and 3-isobutyl-1-methylxanthine (20 micromol/L), also inhibited GCDC-induced apoptosis to a similar extent. Pretreatment with the protein kinase A (PKA) inhibitor, KT5720, prevented the protective effect of CP-cAMP and inhibited CP-cAMP-induced activation of PKA activity. Inhibitors of phosphatidylinositol 3-kinase (PI3K), wortmannin (50 nmol/L), or Ly 294002 (20 micromol/L) also prevented the cytoprotective effect of cAMP. PI3K assays confirmed that wortmannin (50 nmol/L) inhibited PI3K activity, while CP-cAMP had no effect on the activity of this lipid kinase. GCDC increased mitogen-activated protein kinase (MAPK) activity, but had no effect on stress-activated protein kinase (SAPK) activity in hepatocytes. cAMP decreased basal and GCDC-induced MAPK activity and increased SAPK activity. The MAPK kinase inhibitor, PD 98059, inhibited both GCDC-mediated MAPK activation and GCDC-induced apoptosis. 1) agents that increase intracellular cAMP protect against hepatocyte apoptosis induced by hydrophobic bile acids; 2) activation of MAPK by GCDC may be involved in bile acid-induced apoptosis; and 3) cAMP-mediated cytoprotection against bile acid-induced apoptosis appears to involve PKA, MAPK, and PI3K.

  15. DJ-1 Protects Pancreatic Beta Cells from Cytokine- and Streptozotocin-Mediated Cell Death.

    PubMed

    Jain, Deepak; Weber, Gesine; Eberhard, Daniel; Mehana, Amir E; Eglinger, Jan; Welters, Alena; Bartosinska, Barbara; Jeruschke, Kay; Weiss, Jürgen; Päth, Günter; Ariga, Hiroyoshi; Seufert, Jochen; Lammert, Eckhard

    2015-01-01

    A hallmark feature of type 1 and type 2 diabetes mellitus is the progressive dysfunction and loss of insulin-producing pancreatic beta cells, and inflammatory cytokines are known to trigger beta cell death. Here we asked whether the anti-oxidant protein DJ-1 encoded by the Parkinson's disease gene PARK7 protects islet cells from cytokine- and streptozotocin-mediated cell death. Wild type and DJ-1 knockout mice (KO) were treated with multiple low doses of streptozotocin (MLDS) to induce inflammatory beta cell stress and cell death. Subsequently, glucose tolerance tests were performed, and plasma insulin as well as fasting and random blood glucose concentrations were monitored. Mitochondrial morphology and number of insulin granules were quantified in beta cells. Moreover, islet cell damage was determined in vitro after streptozotocin and cytokine treatment of isolated wild type and DJ-1 KO islets using calcein AM/ethidium homodimer-1 staining and TUNEL staining. Compared to wild type mice, DJ-1 KO mice became diabetic following MLDS treatment. Insulin concentrations were substantially reduced, and fasting blood glucose concentrations were significantly higher in MLDS-treated DJ-1 KO mice compared to equally treated wild type mice. Rates of beta cell apoptosis upon MLDS treatment were twofold higher in DJ-1 KO mice compared to wild type mice, and in vitro inflammatory cytokines led to twice as much beta cell death in pancreatic islets from DJ-1 KO mice versus those of wild type mice. In conclusion, this study identified the anti-oxidant protein DJ-1 as being capable of protecting pancreatic islet cells from cell death induced by an inflammatory and cytotoxic setting.

  16. Identification of resolvin D2 receptor mediating resolution of infections and organ protection

    PubMed Central

    Chiang, Nan; Dalli, Jesmond; Colas, Romain A.

    2015-01-01

    Endogenous mechanisms that orchestrate resolution of acute inflammation are essential in host defense and the return to homeostasis. Resolvin (Rv)D2 is a potent immunoresolvent biosynthesized during active resolution that stereoselectively stimulates resolution of acute inflammation. Here, using an unbiased G protein–coupled receptor-β-arrestin–based screening and functional sensing systems, we identified a receptor for RvD2, namely GPR18, that is expressed on human leukocytes, including polymorphonuclear neutrophils (PMN), monocytes, and macrophages (MΦ). In human MΦ, RvD2-stimulated intracellular cyclic AMP was dependent on GPR18. RvD2-stimulated phagocytosis of Escherichia coli and apoptotic PMN (efferocytosis) were enhanced with GPR18 overexpression and significantly reduced by shRNA knockdown. Specific binding of RvD2 to recombinant GPR18 was confirmed using a synthetic 3H-labeled-RvD2. Scatchard analysis gave a Kd of ∼10 nM consistent with RvD2 bioactive concentration range. In both E. coli and Staphylococcus aureus infections, RvD2 limited PMN infiltration, enhanced phagocyte clearance of bacteria, and accelerated resolution. These actions were lost in GPR18-deficient mice. During PMN-mediated second organ injury, RvD2’s protective actions were also significantly diminished in GPR18-deficient mice. Together, these results provide evidence for a novel RvD2–GPR18 resolution axis that stimulates human and mouse phagocyte functions to control bacterial infections and promote organ protection. PMID:26195725

  17. Prostaglandin receptor EP2 protects dopaminergic neurons against 6-OHDA-mediated low oxidative stress

    PubMed Central

    Carrasco, Emilce; Werner, Peter; Casper, Diana

    2008-01-01

    Dopaminergic neurons in the substantia nigra (SN) selectively die in Parkinson’s disease (PD), but it is unclear how and why this occurs. Recent findings implicate prostaglandin E2 (PGE2) and two of its four receptors, namely EP1 and EP2, as mediators of degenerative and protective events in situations of acute and chronic neuronal death. EP1 activation can exacerbate excitotoxic damage in stroke models and our recent study showed that EP1 activation may explain the selective sensitivity of dopaminergic neurons to oxidative stress. Conversely, EP2 activation may be neuroprotective, although toxic effects have also been demonstrated. Here we investigated if and how EP2 activation might alter the survival of dopaminergic neurons following selective low-level oxidative injury evoked by the neurotoxin 6-hydroxydopamine (6-OHDA) in primary neuronal cultures prepared from embryonic rat midbrain. We found that cultured dopaminergic neurons displayed EP2 receptors. Butaprost, a selective EP2 agonist, significantly reduced 6-OHDA neurotoxicity. EP2 receptors are coupled to stimulatory G-proteins (Gs), which activate adenylate cyclase, increasing cAMP synthesis, which then activates protein kinase A (PKA). Both dibutyryl cAMP and forskolin reduced dopaminergic cell loss after 6-OHDA exposure. Conversely, KT5720 and H-89, two structurally distinct high-affinity PKA inhibitors, abolished the protective effect of butaprost, implicating cAMP-dependent PKA activity in the neuroprotection by EP2 activation. Finally, we show that melanized dopaminergic neurons in the human SN express EP2. This pathway warrants consideration as a neuroprotective strategy for PD. PMID:18597941

  18. Prostaglandin receptor EP2 protects dopaminergic neurons against 6-OHDA-mediated low oxidative stress.

    PubMed

    Carrasco, Emilce; Werner, Peter; Casper, Diana

    2008-08-15

    Dopaminergic neurons in the substantia nigra (SN) selectively die in Parkinson's disease (PD), but it is unclear how and why this occurs. Recent findings implicate prostaglandin E(2) (PGE(2)) and two of its four receptors, namely EP1 and EP2, as mediators of degenerative and protective events in situations of acute and chronic neuronal death. EP1 activation can exacerbate excitotoxic damage in stroke models and our recent study showed that EP1 activation may explain the selective sensitivity of dopaminergic neurons to oxidative stress. Conversely, EP2 activation may be neuroprotective, although toxic effects have also been demonstrated. Here we investigated if and how EP2 activation might alter the survival of dopaminergic neurons following selective low-level oxidative injury evoked by the neurotoxin 6-hydroxydopamine (6-OHDA) in primary neuronal cultures prepared from embryonic rat midbrain. We found that cultured dopaminergic neurons displayed EP2 receptors. Butaprost, a selective EP2 agonist, significantly reduced 6-OHDA neurotoxicity. EP2 receptors are coupled to stimulatory G-proteins (Gs), which activate adenylate cyclase, increasing cAMP synthesis, which then activates protein kinase A (PKA). Both dibutyryl cAMP and forskolin reduced dopaminergic cell loss after 6-OHDA exposure. Conversely, KT5720 and H-89, two structurally distinct high-affinity PKA inhibitors, abolished the protective effect of butaprost, implicating cAMP-dependent PKA activity in the neuroprotection by EP2 activation. Finally, we show that melanized dopaminergic neurons in the human SN express EP2. This pathway warrants consideration as a neuroprotective strategy for PD.

  19. Sphingosine kinase 2 mediates cerebral preconditioning and protects mouse brain against ischemic injury

    PubMed Central

    Yung, Lai Ming; Wei, Ying; Qin, Tao; Wang, Yumei; Smith, Charles; Waeber, Christian

    2011-01-01

    Background and purpose Cerebral preconditioning provides insights into endogenous mechanisms that protect the brain from ischemic injury. Hypoxia and the anesthetic isoflurane are powerful preconditioning agents. Recent data show that sphingosine 1-phosphate (S1P) receptor stimulation improves outcome in rodent models of stroke. Endogenous S1P levels are controlled by the expression and activity of sphingosine kinases (SPK). We hypothesize that SPK up-regulation mediates preconditioning induced by isoflurane and hypoxia and reduces ischemic injury. Methods Male wild-type C57BL/J, SPK1−/− and SPK2−/− mice were exposed to isoflurane (IsoPC) or hypoxia preconditioning (HPC) before transient middle cerebral artery occlusion. Infarct volume and neurological outcome were measured 24 hours later. SPK inhibitors (SKI-II and ABC294640) were used to test the involvement of SPK2. Expressions of SPK1, SPK2 and HIF1α were determined. Primary cultures of mouse cortical neurons were exposed to isoflurane before glutamate- or hydrogen peroxide-induced cell death. Results IsoPC and HPC significantly reduced infarct volume and improved neurological outcome in wild-type and SPK1−/− mice, but not in SPK2−/− mice. Pretreatment with SKI-II or ABC294640 abolished the IsoPC-induced tolerance. Western blot showed a rapid and sustained increase in SPK2 level, whereas SPK1 level was similar between preconditioned mice and controls. HIF1α was up-regulated in wild-type IsoPC mice, but not in SPK2−/−. IsoPC protected primary neurons against cell death, which was abolished in ABC294640-treated cells. Conclusions Applying genetic and pharmacological approaches, we demonstrate that neuronal SPK2 isoform plays an important role in cerebral preconditioning. PMID:21980199

  20. RBM3 mediates structural plasticity and protective effects of cooling in neurodegeneration

    PubMed Central

    Peretti, Diego; Bastide, Amandine; Radford, Helois; Verity, Nicholas; Molloy, Colin; Martin, Maria Guerra; Moreno, Julie A.; Steinert, Joern R; Smith, Tim; Dinsdale, David; Willis, Anne E.; Mallucci, Giovanna R.

    2014-01-01

    In the healthy adult brain synapses are continuously remodelled through a process of elimination and formation known as structural plasticity1. Reduction in synapse number is a consistent early feature of neurodegenerative diseases2, 3, suggesting deficient compensatory mechanisms. While much is known about toxic processes leading to synaptic dysfunction and loss in these disorders2,3, how synaptic regeneration is affected is unknown. In hibernating mammals, cooling induces loss of synaptic contacts, which are reformed on rewarming, a form of structural plasticity4, 5. We have found that similar changes occur in artificially cooled laboratory rodents. Cooling and hibernation also induce a number cold-shock proteins in the brain, including the RNA binding protein, RBM36. The relationship of such proteins to structural plasticity is unknown. Here we show that synapse regeneration is impaired in mouse models of neurodegenerative disease, in association with the failure to induce RBM3. In both prion-infected and 5×FAD (Alzheimer-type) mice7, the capacity to regenerate synapses after cooling declined in parallel with the loss of induction of RBM3. Enhanced expression of RBM3 in the hippocampus prevented this deficit and restored the capacity for synapse reassembly after cooling. Further, RBM3 over-expression, achieved either by boosting endogenous levels through hypothermia prior to the loss of the RBM3 response, or by lentiviral delivery, resulted in sustained synaptic protection in 5×FAD mice and throughout the course of prion disease, preventing behavioural deficits and neuronal loss and significantly prolonging survival. In contrast, knockdown of RBM3 exacerbated synapse loss in both models and accelerated disease and prevented the neuroprotective effects of cooling. Thus, deficient synapse regeneration, mediated at least in part by failure of the RBM3 stress response, contributes to synapse loss throughout the course of neurodegenerative disease. The data support

  1. INHIBITION OF SOLUBLE EPOXIDE HYDROLASE DOES NOT PROTECT AGAINST ENDOTOXIN-MEDIATED HEPATIC INFLAMMATION

    PubMed Central

    Fife, Kimberly L.; Liu, YingMei; Schmelzer, Kara R.; Tsai, Hsing-Ju; Kim, In-Hae; Morisseau, Christophe; Hammock, Bruce D.; Kroetz, Deanna L.

    2009-01-01

    Epoxyeicosatrienoic acids (EETs) are derived from cytochrome P450 (CYP)-catalyzed epoxygenation of arachidonic acid and have emerged as important mediators of numerous biological effects. The major elimination pathway for EETs is through soluble epoxide hydrolase (sEH) catalyzed metabolism to dihydroxyeicosatrienoic acids (DHETs). Based on previous studies showing that EETs have anti-inflammatory effects, we hypothesized that chronic inhibition of sEH would attenuate a lipopolysaccharide (LPS)-induced inflammatory response in vivo. Continuous dosing of the sEH inhibitors 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA), a polyethylene glycol ester of AUDA (AUDA-PEG), and 1-adamantan-1-yl-3-(5-(2-(2-ethoxyethoxy)ethoxy)pentyl)urea (AEPU) resulted in robust exposure to the inhibitor and target engagement, as evidenced by significant increases in plasma EET/DHET ratios following six days of inhibitor treatment. However, sEH inhibitor treatment was not associated with an attenuation of LPS-induced inflammatory gene expression in the liver and AUDA did not protect from LPS-induced neutrophil infiltration. Furthermore, Ephx2 −/− mice that lack sEH expression and have significantly increased plasma EET/DHET ratios were not protected from LPS-induced inflammatory gene expression or neutrophil accumulation in the liver. LPS did have an effect on sEH expression and function, as evident from a significant downregulation of Ephx2 mRNA and a significant shift in plasma EET/DHET ratios four hours after LPS treatment. In conclusion, there was no evidence that increasing EET levels in vivo could modulate an LPS-induced inflammatory response in the liver. However, LPS did have significant effects on plasma eicosanoid levels and hepatic Ephx2 expression, suggesting that in vivo EET levels are modulated in response to an inflammatory signal. PMID:18815352

  2. Common and unique cis-acting elements mediate xanthotoxin and flavone induction of the generalist P450 CYP321A1.

    PubMed

    Zhang, Chunni; Wong, Andrew; Zhang, Yalin; Ni, Xinzhi; Li, Xianchun

    2014-09-29

    How polyphagous herbivores up-regulate their counterdefense genes in response to a broad range of structurally different allelochemicals remains largely unknown. To test whether this is accomplished by having more allelochemical-response elements or the similar number of functionally more diverse elements, we mapped out the cis-acting elements mediating the induction of the allelochemical-metabolizing CYP321A1 from the generalist Helicoverpa zea by xanthotoxin and flavone, two structurally distinct allelochemicals with very different encounter rate by this species. Seven xanthotoxin-responsive elements were localized by analyzing promoter activities of varying length of CYP321A1 promoter in H. zea fatbody cells. Compared with the 5 flavone-responsive elements mapped out previously, there are four common elements (1 essential element, 2 enhancers, and 1 negative element) mediating induction of CYP321A1 by both of the two allelochemicals. The remaining four elements (3 enhancers and 1 negative element), however, only regulate induction of CYP321A1 by either of the two allelochemicals. Co-administration of the two allelochemicals resulted in an induction fold that is significantly lower than the expected additive value of the two allelochemicals. These results indicate that xanthotoxin- and flavone-induced expressions of CYP321A1 are mediated mainly by the functionally more diverse common elements although the allelochemical-unique elements also play a role.

  3. Hypoxia-induced endothelial NO synthase gene transcriptional activation is mediated through the tax-responsive element in endothelial cells.

    PubMed

    Min, Jiho; Jin, Yoon-Mi; Moon, Je-Sung; Sung, Min-Sun; Jo, Sangmee Ahn; Jo, Inho

    2006-06-01

    Although hypoxia is known to induce upregulation of endothelial NO synthase (eNOS) gene expression, the underlying mechanism is largely unclear. In this study, we show that hypoxia increases eNOS gene expression through the binding of phosphorylated cAMP-responsive element binding (CREB) protein (pCREB) to the eNOS gene promoter. Hypoxia (1% O2) increased both eNOS expression and NO production, peaking at 24 hours, in bovine aortic endothelial cells, and these increases were accompanied by increases in pCREB. Treatment with the protein kinase A inhibitor H-89 or transfection with dominant-negative inhibitor of CREB reversed the hypoxia-induced increases in eNOS expression and NO production, with concomitant inhibition of the phosphorylation of CREB induced by hypoxia, suggesting an involvement of protein kinase A/pCREB-mediated pathway. To map the regulatory elements of the eNOS gene responsible for pCREB binding under hypoxia, we constructed an eNOS gene promoter (-1600 to +22 nucleotides) fused with a luciferase reporter gene [pGL2-eNOS(-1600)]. Hypoxia (for 24-hour incubation) increased the promoter activity by 2.36+/-0.18-fold in the bovine aortic endothelial cells transfected with pGL2-eNOS(-1600). However, progressive 5'-deletion from -1600 to -873 completely attenuated the hypoxia-induced increase in promoter activity. Electrophoretic mobility shift, anti-pCREB antibody supershift, and site-specific mutation analyses showed that pCREB is bound to the Tax-responsive element (TRE) site, a cAMP-responsive element-like site, located at -924 to -921 of the eNOS promoter. Our data demonstrate that the interaction between pCREB and the Tax-responsive element site within the eNOS promoter may represent a novel mechanism for the mediation of hypoxia-stimulated eNOS gene expression.

  4. Refined live attenuated Salmonella enterica serovar Typhimurium and Enteritidis vaccines mediate homologous and heterologous serogroup protection in mice.

    PubMed

    Tennant, Sharon M; Schmidlein, Patrick; Simon, Raphael; Pasetti, Marcela F; Galen, James E; Levine, Myron M

    2015-12-01

    Invasive nontyphoidal Salmonella (NTS) infections constitute a major health problem among infants and toddlers in sub-Saharan Africa; these infections also occur in infants and the elderly in developed countries. We genetically engineered a Salmonella enterica serovar Typhimurium strain of multilocus sequence type 313, the predominant genotype circulating in sub-Saharan Africa. We evaluated the capacities of S. Typhimurium and Salmonella enterica serovar Enteritidis ΔguaBA ΔclpX live oral vaccines to protect mice against a highly lethal challenge dose of the homologous serovar and determined protection against other group B and D serovars circulating in sub-Saharan Africa. The vaccines S. Typhimurium CVD 1931 and S. Enteritidis CVD 1944 were immunogenic and protected BALB/c mice against 10,000 50% lethal doses (LD50) of S. Typhimurium or S. Enteritidis, respectively. S. Typhimurium CVD 1931 protected mice against the group B serovar Salmonella enterica serovar Stanleyville (91% vaccine efficacy), and S. Enteritidis CVD 1944 protected mice against the group D serovar Salmonella enterica serovar Dublin (85% vaccine efficacy). High rates of survival were observed when mice were infected 12 weeks postimmunization, indicating that the vaccines elicited long-lived protective immunity. Whereas CVD 1931 did not protect against S. Enteritidis R11, CVD 1944 did mediate protection against S. Typhimurium D65 (81% efficacy). These findings suggest that a bivalent (S. Typhimurium and S. Enteritidis) vaccine would provide broad protection against the majority of invasive NTS infections in sub-Saharan Africa.

  5. Refined Live Attenuated Salmonella enterica Serovar Typhimurium and Enteritidis Vaccines Mediate Homologous and Heterologous Serogroup Protection in Mice

    PubMed Central

    Schmidlein, Patrick; Simon, Raphael; Pasetti, Marcela F.; Galen, James E.; Levine, Myron M.

    2015-01-01

    Invasive nontyphoidal Salmonella (NTS) infections constitute a major health problem among infants and toddlers in sub-Saharan Africa; these infections also occur in infants and the elderly in developed countries. We genetically engineered a Salmonella enterica serovar Typhimurium strain of multilocus sequence type 313, the predominant genotype circulating in sub-Saharan Africa. We evaluated the capacities of S. Typhimurium and Salmonella enterica serovar Enteritidis ΔguaBA ΔclpX live oral vaccines to protect mice against a highly lethal challenge dose of the homologous serovar and determined protection against other group B and D serovars circulating in sub-Saharan Africa. The vaccines S. Typhimurium CVD 1931 and S. Enteritidis CVD 1944 were immunogenic and protected BALB/c mice against 10,000 50% lethal doses (LD50) of S. Typhimurium or S. Enteritidis, respectively. S. Typhimurium CVD 1931 protected mice against the group B serovar Salmonella enterica serovar Stanleyville (91% vaccine efficacy), and S. Enteritidis CVD 1944 protected mice against the group D serovar Salmonella enterica serovar Dublin (85% vaccine efficacy). High rates of survival were observed when mice were infected 12 weeks postimmunization, indicating that the vaccines elicited long-lived protective immunity. Whereas CVD 1931 did not protect against S. Enteritidis R11, CVD 1944 did mediate protection against S. Typhimurium D65 (81% efficacy). These findings suggest that a bivalent (S. Typhimurium and S. Enteritidis) vaccine would provide broad protection against the majority of invasive NTS infections in sub-Saharan Africa. PMID:26351285

  6. The protective role of prosocial behaviors on antisocial behaviors: the mediating effects of deviant peer affiliation.

    PubMed

    Carlo, Gustavo; Mestre, Maria Vicenta; McGinley, Meredith M; Tur-Porcar, Ana; Samper, Paula; Opal, Deanna

    2014-06-01

    Prosocial behaviors, actions intended to help others, may serve a protective function against association with deviant peers and subsequent delinquent and antisocial behaviors. The present study examined the relations among specific types of prosocial behaviors, deviant peer affiliation, and delinquent and aggressive behaviors. Six hundred and sixty-six adolescents (46% girls; M age = 15.33, SD = .47) from Valencia, Spain completed questionnaires of prosocial behaviors, affiliation with deviant peers, antisocial behaviors, and aggression. Results showed that antisocial behaviors were negatively related only to specific forms of prosocial behaviors. Further analyses showed that deviant peer affiliation mediated the relations between compliant prosocial behavior and delinquency and aggression. Although altruism was not directly related to delinquency and aggression, it was indirectly linked to the behaviors via deviant peer affiliation. Discussion focuses on the relevance of specific forms of prosocial behaviors to antisocial behaviors and the risk of deviant peers for prosocial youth. Copyright © 2014 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

  7. IFN-γ signaling to astrocytes protects from autoimmune mediated neurological disability.

    PubMed

    Hindinger, Claudia; Bergmann, Cornelia C; Hinton, David R; Phares, Timothy W; Parra, Gabriel I; Hussain, Shabbir; Savarin, Carine; Atkinson, Roscoe D; Stohlman, Stephen A

    2012-01-01

    Demyelination and axonal degeneration are determinants of progressive neurological disability in patients with multiple sclerosis (MS). Cells resident within the central nervous system (CNS) are active participants in development, progression and subsequent control of autoimmune disease; however, their individual contributions are not well understood. Astrocytes, the most abundant CNS cell type, are highly sensitive to environmental cues and are implicated in both detrimental and protective outcomes during autoimmune demyelination. Experimental autoimmune encephalomyelitis (EAE) was induced in transgenic mice expressing signaling defective dominant-negative interferon gamma (IFN-γ) receptors on astrocytes to determine the influence of inflammation on astrocyte activity. Inhibition of IFN-γ signaling to astrocytes did not influence disease incidence, onset, initial progression of symptoms, blood brain barrier (BBB) integrity or the composition of the acute CNS inflammatory response. Nevertheless, increased demyelination at peak acute disease in the absence of IFN-γ signaling to astrocytes correlated with sustained clinical symptoms. Following peak disease, diminished clinical remission, increased mortality and sustained astrocyte activation within the gray matter demonstrate a critical role of IFN-γ signaling to astrocytes in neuroprotection. Diminished disease remission was associated with escalating demyelination, axonal degeneration and sustained inflammation. The CNS infiltrating leukocyte composition was not altered; however, decreased IL-10 and IL-27 correlated with sustained disease. These data indicate that astrocytes play a critical role in limiting CNS autoimmune disease dependent upon a neuroprotective signaling pathway mediated by engagement of IFN-γ receptors.

  8. IFN-γ Signaling to Astrocytes Protects from Autoimmune Mediated Neurological Disability

    PubMed Central

    Hindinger, Claudia; Bergmann, Cornelia C.; Hinton, David R.; Phares, Timothy W.; Parra, Gabriel I.; Hussain, Shabbir; Savarin, Carine; Atkinson, Roscoe D.; Stohlman, Stephen A.

    2012-01-01

    Demyelination and axonal degeneration are determinants of progressive neurological disability in patients with multiple sclerosis (MS). Cells resident within the central nervous system (CNS) are active participants in development, progression and subsequent control of autoimmune disease; however, their individual contributions are not well understood. Astrocytes, the most abundant CNS cell type, are highly sensitive to environmental cues and are implicated in both detrimental and protective outcomes during autoimmune demyelination. Experimental autoimmune encephalomyelitis (EAE) was induced in transgenic mice expressing signaling defective dominant-negative interferon gamma (IFN-γ) receptors on astrocytes to determine the influence of inflammation on astrocyte activity. Inhibition of IFN-γ signaling to astrocytes did not influence disease incidence, onset, initial progression of symptoms, blood brain barrier (BBB) integrity or the composition of the acute CNS inflammatory response. Nevertheless, increased demyelination at peak acute disease in the absence of IFN-γ signaling to astrocytes correlated with sustained clinical symptoms. Following peak disease, diminished clinical remission, increased mortality and sustained astrocyte activation within the gray matter demonstrate a critical role of IFN-γ signaling to astrocytes in neuroprotection. Diminished disease remission was associated with escalating demyelination, axonal degeneration and sustained inflammation. The CNS infiltrating leukocyte composition was not altered; however, decreased IL-10 and IL-27 correlated with sustained disease. These data indicate that astrocytes play a critical role in limiting CNS autoimmune disease dependent upon a neuroprotective signaling pathway mediated by engagement of IFN-γ receptors. PMID:22848713

  9. Protection of membrane cholesterol by sphingomyelin against free radical-mediated oxidation

    PubMed Central

    Sargis, Robert M; Subbaiah, Papasani V.

    2006-01-01

    Although the free radical-mediated oxidation of free cholesterol (FC) is critical in the generation of regulatory sterols and in atherogenesis, the physiological regulation of this process is poorly understood. We tested the hypothesis that sphingomyelin (SM), a major phospholipid of cell membranes, which is closely associated with FC, protects FC against oxidation, because of its unique structure, and affinity to the sterol. We employed phosphatidylcholine (PC) liposomes containing varying amounts of SM, and either radioactive FC or a fluorescent analog, dehydroergosterol (DHE), and determined the oxidative decay of the sterol in presence of 2,2′ azo bis(2-amidinopropane hydrochloride) (AAPH). Incorporation of 25 mol% of SM in the liposomes inhibited the oxidation of FC or DHE by up to 50%. This inhibition was specific for SM among phospholipids, and was abolished by sphingomyelinase treatment. SM was not degraded during the oxidation reaction, and its effect was not dependent upon the nature of the oxidizing agent, because it also inhibited sterol oxidation by FeSO4/ascorbate, and by cholesterol oxidase. These studies show that SM plays a physiological role in the regulation of cholesterol oxidation by free radicals. PMID:16785023

  10. Verbascoside isolated from Tectona grandis mediates gastric protection in rats via inhibiting proton pump activity.

    PubMed

    Singh, Neetu; Shukla, Nivedita; Singh, Pratibha; Sharma, Rolee; Rajendran, S M; Maurya, Rakesh; Palit, Gautam

    2010-10-01

    Evidences have suggested that Tectona grandis (TG) attenuates gastric mucosal injury; however its mechanism has not yet been established. The aim of present study was to evaluate the gastroprotective mechanism of ethanolic extract of TG (E-EtOH), butanolic fraction (Fr-Bu) and to identify its active constituents. Anti-ulcer activities were evaluated against cold restraint (CRU) and pyloric ligation (PL) induced gastric ulcer models and further confirmed through H(+) K(+)-ATPase inhibitory activity. Cytoprotective activity was evaluated in alcohol (AL) induced gastric ulcer model and further through PGE(2) level. E-EtOH and Fr-Bu attenuated ulcer formation in CRU. Moreover E-EtOH and Fr-Bu displayed potent anti-secretory activity as evident through reduced free acidity and pepsin activity in PL, confirmed further by in vitro inhibition of H(+) K(+)-ATPase activity. In addition cytoprotective potential of E-EtOH and Fr-Bu were apparent with protection in AL model, increased PGE(2) content and enhanced mucin level in PL. Phytochemical investigations of Fr-Bu yielded terpenoides and a phenolic glycoside, verbascoside. The anti-secretory mechanism of verbascoside mediated apparently through inhibition of H(+) K(+)-ATPase with corresponding decrease in plasma gastrin level, is novel to our finding. Gastroprotection elicited by TG might be through proton pump inhibition and consequent augmentation of the defensive mechanism.

  11. Renal damage mediated by oxidative stress: a hypothesis of protective effects of red wine.

    PubMed

    Rodrigo, Ramón; Rivera, Gonzalo

    2002-08-01

    Over the last decade, oxidative stress has been implicated in the pathogenesis of a wide variety of seemingly unrelated renal diseases. Epidemiological studies have documented an association of moderate wine consumption with a decreased risk of cardiovascular and neurological diseases; however, similar studies in the kidney are still lacking. The kidney is an organ highly vulnerable to damage caused by reactive oxygen species (ROS), likely due to the abundance of polyunsaturated fatty acids in the composition of renal lipids. ROS are involved in the pathogenic mechanism of conditions such as glomerulosclerosis and tubulointerstitial fibrosis. The health benefits of moderate consumption of red wine can be partly attributed to its antioxidant properties. Indeed, the kidney antioxidant defense system is enhanced after chronic exposure to moderate amounts of wine, a response arising from the combined effects of ethanol and the nonalcoholic components, mainly polyphenols. Polyphenols behave as potent ROS scavengers and metal chelators; ethanol, in turn, modulates the activity of antioxidant enzymes. Therefore, a hypothesis that red wine causes a decreased vulnerability of the kidney to the oxidative challenges could be proposed. This view is partly supported by direct evidences indicating that wine and antioxidants isolated from red wine, as well as other antioxidants, significantly attenuate or prevent the oxidative damage to the kidney. The present hypothesis paper provides a collective body of evidence suggesting a protective role of moderate wine consumption against the production and progression of renal diseases, based on the existing concepts on the pathophysiology of kidney injury mediated by oxidative stress.

  12. Renal peroxidative changes mediated by oxalate: the protective role of fucoidan.

    PubMed

    Veena, Coothan Kandaswamy; Josephine, Anthony; Preetha, Sreenivasan P; Varalakshmi, Palaninathan; Sundarapandiyan, Rajaguru

    2006-10-04

    Oxalate, one of the major constituents of renal stones is known to induce free radicals which damage the renal membrane. Damaged epithelia might act as nidi for stone formation aggravating calcium oxalate precipitation during hyperoxaluria. In the present study, the beneficial effects of fucoidan on oxalate-induced free radical injury were investigated. Male Wistar rats were divided into four groups. Hyperoxaluria was induced in two groups by administration of 0.75% ethylene glycol in drinking water for 28 days and one of them was treated with fucoidan from Fucus vesiculosus at a dose of 5 mg/kg b.wt subcutaneously commencing from the 8th day of induction. A control and drug control (fucoidan alone) was also included in the study. The extent of renal injury in hyperoxaluria was evident from the increased activities of alkaline phosphatase, gamma-glutamyl transferase, beta-glucuronidase, N-acetyl-beta-D-glucosaminidase in urine. There was a positive correlation between plasma malondialdehyde levels and renal membrane damage indicating a striking relation between free radical formation and cellular injury. Increased protein carbonyl and decreased thiols further exemplified the oxidative milieu prevailing during hyperoxaluria. Decreased renal membrane ATPases accentuated the renal membrane damage induced by oxalate. Renal microscopic analysis showed abnormal findings in histology as an evidence of oxalate damage. The above biochemical and histopathological discrepancies were abrogated with fucoidan administration, indicating its protective role in oxalate mediated peroxidative injury.

  13. TrkB-mediated protection against circadian sensitivity to noise trauma in the murine cochlea.

    PubMed

    Meltser, Inna; Cederroth, Christopher R; Basinou, Vasiliki; Savelyev, Sergey; Lundkvist, Gabriella S; Canlon, Barbara

    2014-03-17

    Noise-induced hearing loss (NIHL) is a debilitating sensory impairment affecting 10%-15% of the population, caused primarily through damage to the sensory hair cells or to the auditory neurons. Once lost, these never regenerate [1], and no effective drugs are available [2, 3]. Emerging evidence points toward an important contribution of synaptic ribbons in the long-term coupling of the inner hair cell and afferent neuron synapse to maintain hearing [4]. Here we show in nocturnal mice that night noise overexposure triggers permanent hearing loss, whereas mice overexposed during the day recover to normal auditory thresholds. In view of this time-dependent sensitivity, we identified a self-sustained circadian rhythm in the isolated cochlea, as evidenced by circadian expression of clock genes and ample PERIOD2::LUCIFERASE oscillations, originating mainly from the primary auditory neurons and hair cells. The transcripts of the otoprotecting brain-derived neurotrophic factor (BDNF) showed higher levels in response to day noise versus night noise, suggesting that BDNF-mediated signaling regulates noise sensitivity throughout the day. Administration of a selective BDNF receptor, tropomyosin-related kinase type B (TrkB), in the night protected the inner hair cell's synaptic ribbons and subsequent full recovery of hearing thresholds after night noise overexposure. The TrkB agonist shifted the phase and boosted the amplitude of circadian rhythms in the isolated cochlea. These findings highlight the coupling of circadian rhythmicity and the TrkB receptor for the successful prevention and treatment of NIHL.

  14. Hydrogen sulfide mediates the protection of dietary restriction against renal senescence in aged F344 rats

    PubMed Central

    Wang, Wen-juan; Cai, Guang-yan; Ning, Yi-chun; Cui, Jing; Hong, Quan; Bai, Xue-yuan; Xu, Xiao-meng; Bu, Ru; Sun, Xue-feng; Chen, Xiang-mei

    2016-01-01

    Renal aging is always accompanied by increased oxidative stress. Hydrogen sulfide (H2S) can be up-regulated by 50% dietary restriction (DR) for 7-day and can block mitochondrial oxidative stress. H2S production exerts a critical role in yeast, worm, and fruit fly models of DR-mediated longevity. In this study, we found that renal aging could be attenuated by 30% DR for 6-month (DR-6M) and life-long (DR-LL), but not for 6-week (DR-6W). The expressions of cystathionine-γ-lyase (CGL) and cystathionine-β- synthase (CBS) were improved by DR-6M and DR-LL. Endogenous H2S production shared the same trend with CBS and CGL, while glutathione (GSH) didn’t. When comparing efficiencies of DR for different durations, more evident production of H2S was found in DR-6M and DR-LL than in DR-6W. Finally the level of oxidative stress was improved by DR-6M and DR-LL rather than by DR-6W. It concluded that aged rats had the ability to produce enough H2S on 30% DR interventions protecting against renal aging, and the effect of DR for long-term were more significant than that of DR for short-term. PMID:27456368

  15. Protective Effect of Zingiber officinale Against Dalton's Lymphoma Ascites Tumour by Regulating Inflammatory Mediator and Cytokines.

    PubMed

    Rubila, Sundararaj; Ranganathan, Thottiam Vasudevan; Sakthivel, Kunnathur Murugesan

    2016-12-01

    The aim of the present investigation was to evaluate Zingiber officinale paste against Dalton's lymphoma ascites (DLA)-induced tumours in Swiss albino mice. Experimental animals received Z. officinale paste (low dose 100 mg/kg bw and high dose 500 mg/kg bw) orally for eight alternative days. Treatment with Z. officinale paste showed significant increase in haemoglobin level and decrease in aspartate amino transferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and gamma glutamyl transferase (γ-GT) level. Z. officinale paste reduced the inflammatory mediators and cytokine levels, such as inducible nitric oxide (iNOS), tumour necrosis factor level (TNF-α) and interleukin-1β (IL-1β). Treatment with Z. officinale paste also significantly increased the antioxidant enzyme level, such as superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH) and glutathione transferase (GST), and decreased the lipid peroxidation. Treatment also increased the vitamin C and E levels in treated animals compared with the DLA-bearing host. Histopathological studies also confirmed the protective influence of Z. officinale paste against DLA. The present study suggested that Z. officinale paste could be used as natural spice and a potent antitumour agent.

  16. Does placental MDSC-mediated modulation of arginine levels help protect the foetus from auxotrophic pathogens?

    PubMed

    Ismail, Abdul Qader Tahir

    2017-05-02

    Myeloid-derived suppressor cells (MDSCs) are immunosuppressive precursors of dendritic cells, macrophages and granulocytes. MDSCs normally quickly differentiate, but have elevated levels in chronic infection and cancer, where they help tumours evade the immune system through induction of T-cell dysfunction. MDSC levels are also raised in pregnancy, and in the neonate. During pregnancy they may help to prevent maternal rejection of the semiallogenic foetus. In the immediate postnatal period they may aid in allowing tolerance of gut microbiological colonisation and non-pathological environmental antigens. MDSC immunosuppression involves reduction of arginine levels, which leads to downregulation of T-cell receptor (TCR) and cell proliferation. Arginine is also involved in replication, and virulence of a variety of viruses and bacteria, including Hepatitis D, HIV-1, Herpes simplex, Adenovirus, Staphylococci, Neisseria gonorrhoea, Escherichia coli, and Streptococci. Given the above it could be hypothesised that MDSC-mediated reduction in levels during pregnancy and the perinatal period is not just a by-product of T-cell immunosuppression, but potentially a primitive part of the innate immune system. Increased arginase activity would therefore serve a dual purpose, inhibiting the adaptive immune system whilst also providing a degree of protection against infection by arginine auxotrophic pathogens.

  17. Cystatin C protects neuronal cells against mutant copper-zinc superoxide dismutase-mediated toxicity

    PubMed Central

    Watanabe, S; Hayakawa, T; Wakasugi, K; Yamanaka, K

    2014-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the selective and progressive loss of motor neurons. Cystatin C (CysC), an endogenous cysteine protease inhibitor, is a major protein component of Bunina bodies observed in the spinal motor neurons of sporadic ALS and is decreased in the cerebrospinal fluid of ALS patients. Despite prominent deposition of CysC in ALS, the roles of CysC in the central nervous system remain unknown. Here, we identified the neuroprotective activity of CysC against ALS-linked mutant Cu/Zn-superoxide dismutase (SOD1)-mediated toxicity. We found that exogenously added CysC protected neuronal cells including primary cultured motor neurons. Moreover, the neuroprotective property of CysC was dependent on the coordinated activation of two distinct pathways: autophagy induction through AMPK-mTOR pathway and inhibition of cathepsin B. Furthermore, exogenously added CysC was transduced into the cells and aggregated in the cytosol under oxidative stress conditions, implying a relationship between the neuroprotective activity of CysC and Bunina body formation. These data suggest CysC is an endogenous neuroprotective agent and targeting CysC in motor neurons may provide a novel therapeutic strategy for ALS. PMID:25356866

  18. Protective effect of rutin on humoral and cell mediated immunity in rat model.

    PubMed

    Ganeshpurkar, Aditya; Saluja, Ajay K

    2017-08-01

    Diet and dietary intake can persuade the development, safeguard and proper functioning of immune system. Ruin, an important bioflavonoid, is abundantly found in various foodstuffs. Rutin has been acknowledged for its protective and beneficial effects on various aspects of the biological system. The present study was aimed to examine the effect of rutin on the regulation of the immune response in experimental animal models. Effect of rutin of cellular immunity was determined by delayed-type hypersensitivity (DTH) response, carbon clearance assay, leucocyte mobilization test, and cyclophosphamide-induced myelosuppression, whereas humoral immunity was analyzed by the haemagglutinating antibody (HA) titre assay. Rutin (25, 50 and 100 mg/kg, p.o.) evoked a significant increase in antibody titre in the haemagglutination test, increased immunoglobulin levels, and enhanced the delayed type hypersensitivity reaction induced by sheep red blood cells. It also significantly restored the functioning of leucocytes in cyclophosphamide treated rats and augmented phagocytic index in the carbon clearance assay. The outcomes from the present study indicate that rutin possesses sufficient potential for increasing immune activity by cellular and humoral mediated mechanisms. Copyright © 2017. Published by Elsevier B.V.

  19. NF-E2 related factor 2 activation and heme oxygenase-1 induction by tert-butylhydroquinone protect against deltamethrin-mediated oxidative stress in PC12 cells.

    PubMed

    Li, Huang Yuan; Zhong, Yu Fang; Wu, Si Ying; Shi, Nian

    2007-09-01

    Recent findings suggest that oxidative stress caused by pyrethroid pesticides could be closely involved in the neurotoxicity. tert-Butylhydroquinone ( tBHQ) is a known inducer of Nrf2-mediated transcription, and treatment of cells with tBHQ can confer protection against H 2O 2 and 6-hydroxydopamine (6-OHDA). In this study, we investigated the neuroprotective effect of tBHQ against deltamethrin (DM)-induced oxidative stress using rat PC12 adrenal pheochromocytoma cells. The pretreatment of PC12 cells with tBHQ significantly reduced DM-induced generation of reactive oxygen species (ROS) and increased intracellular ionized calcium ([Ca (2+)] i). We also observed that DM or tBHQ induced the expression of NF-E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1), a Nrf2-regulated gene. In addition, the Nrf2 antioxidant responsive element (ARE) pathways activated by tBHQ caused a partial inhibition of the DM-induced Nrf2 and HO-1 expression. Altogether, our data clearly indicate that an activation of Nrf2/ARE pathways in PC12 cells by tBHQ treatment protects cells from DM-induced oxidative stress and regulates DM- mediated adaptive responses in PC12 cells via translocation of Nrf2.

  20. Dust-mediated loading of trace and major elements to Wasatch Mountain snowpack.

    PubMed

    Carling, Gregory T; Fernandez, Diego P; Johnson, William P

    2012-08-15

    Depth-integrated snow columns were collected at 12 sites across the central Wasatch Mountains, Utah, during March and April 2010 to determine concentrations of trace elements, major anions and cations, and pH. Sample collection was conducted at or near maximum snow accumulation prior to the onset of melt, and included spring dust events driven by southerly pre-frontal winds. Snow samples were melted in the laboratory and subsampled for analyses on filtered (0.45 μm) and unfiltered fractions. All measured elements (Al, As, Ba, Ca, Co, Cr, Cu, Fe, Hg, K, Li, Mg, Mn, Na, Ni, Pb, Sb, Sr, Ti, Tl, U, V, and Zn) and major anions (Cl, NO(3), and SO(4)) displayed significant increases in concentration (for example, factor of 2 to 5 increases for As, Cr, Hg, and Pb) between the six sites sampled in March (prior to dust events) and the six sites sampled in April (after dust events). Acid neutralizing capacity and pH were also elevated in April relative to March snowpack. Comparison of elemental concentration in the particulate (>0.45 μm; difference between unfiltered and filtered concentration) and soluble (<0.45 μm; filtered concentration) fractions shows that the concentration increase between March and April snowpack for the trace elements is primarily a result of association with dust particles >0.45 μm. The results suggest that the majority of trace element loading to the Wasatch snowpack occurs via dust deposition. The major elements were primarily loaded in the <0.45 μm fraction, suggesting deposition of soluble dust particles. The overall findings of this paper are similar to other studies regarding the role of dust on nutrient and trace element accumulation in soils and lake sediments, but to our knowledge this is the first study that compares trace element chemistry of seasonal snowpack before and after dust deposition events.

  1. Theoretical Rationale of Heating Block for Testing Bench of Aerospace Crafts Thermal Protection Elements

    NASA Astrophysics Data System (ADS)

    Petrova, Anna A.; Reznik, Sergey V.

    2016-02-01

    The theoretical rationale for the structural layout of a testing bench with zirconium dioxide heating elements on the basis of modelling radiative-conductive heat transfer are presented. The numerical simulation of radiative-conductive heat transfer for the two-dimensional scaled model of the testing segment with the finite-element analysis software package Ansys 15.0 are performed. The simulation results showed that for the selected layout of the heaters the temperature non-uniformity along the length of the sample over time will not exceed 3 % even at a temperature of 2000 K.

  2. Isotope evidence for the microbially mediated formation of elemental sulfur: A case study from Lake Peten Itza, Guatemala

    NASA Astrophysics Data System (ADS)

    Turchyn, A. V.; Bennett, V. A.; Hodell, D. A.

    2013-12-01

    Elemental, or native, sulfur nodules or veins can be formed during aqueous diagenesis and have been found in a range of natural environments, including lake sediments. What governs the formation of elemental sulfur remains enigmatic, although it is widely thought to be microbially-mediated. While most of the literature suggests elemental sulfur is formed by partial re-oxidation of hydrogen sulphide, elemental sulfur can also form during incomplete bacterial sulfate reduction or during aborted sulfur disproportionation. Lake Peten Itza, in Northern Guatemala, which was cored during the International Continental Drilling program in 2006, is one of the few places where elemental sulfur nodules are forming during microbial diagenesis today. Sulfur isotopes are strongly partitioned during bacterial sulfate reduction and the magnitude of the partitioning yields insight into the microbial reactions and environmental conditions. For example, sulfate reduction that terminates at elemental sulfur likely requires the use of the intracellular trithonite pathway, which may drive larger overall sulfur isotope fractionation between the precursor sulfate and the elemental sulfur product. Sulfur isotopes combined with oxygen isotopes in the precursor sulfate may provide even more information about microbial mechanisms. We present coupled pore fluid sulfate concentrations and sulfur and oxygen isotope measurements, as well as co-existing nodule sulfur isotopes from the Lake Peten Itza sediments. The δ34S of the nodules in the lake sediments ranges from +12 to -13‰, often within a single nodule. This suggests formation from an open system where sulfate is replenished by diffusion, as might be expected during pore fluid diagenesis. The δ34S of the pore fluid sulfate at the depth of nodule formation is between 50 and 60‰ (versus the precursor gypsum which is 17 to 18‰) suggesting a large sulfur isotope fractionation between sulfate and elemental sulfur (38 to 73‰). Pyrite was

  3. Chemical mediation as a structuring element in marine gastropod predator-prey interactions.

    PubMed

    Bornancin, L; Bonnard, I; Mills, S C; Banaigs, B

    2017-06-07

    Covering: up to 2017Chemical mediation regulates behavioral interactions between species and thus affects population structure, community organization and ecosystem function. Among marine taxa that have developed chemical mediation strategies, gastropods belong to a diverse group of molluscs found worldwide, including species with a coiled, reduced or absent shell. Most gastropods use natural products to mediate a wide range of behaviors such as defense, prey location or interactions with con- and hetero-geners. Their chemically defended diet, such as cyanobacteria, algae, sponges, bryozoans and tunicates, provides them with a considerable opportunity either as shelter from predators, or as a means to enhance their own chemical defense. In addition to improving their defenses, molluscs also use prey secondary metabolites in complex chemical communication including settlement induction, prey detection and feeding preferences. The assimilation of prey secondary metabolites further provides the opportunity for interactions with conspecifics via diet-derived chemical cues or signals. This review intends to provide an overview on the sequestration, detoxification, and biotransformation of diet-derived natural products, as well as the role of these compounds as chemical mediators in gastropod-prey interactions.

  4. Finite element analysis of various methods for protection of concrete structures against spalling during fire

    NASA Astrophysics Data System (ADS)

    Witek, A.; Gawin, D.; Pesavento, F.; Schrefler, B. A.

    2007-02-01

    A mathematical model of hygro-thermo-mechanical phenomena in heated concrete, treated as multiphase porous material is briefly presented. Some modifications necessary to analyse high-temperature performance of a concrete containing the PP-fibres have been introduced, experimentally validated and applied for analysis of performance of a concrete tunnel lining during a 10-MW fire and the ISO standard fire. Three methods for protecting concrete structures against excessive degradation in fire conditions have been numerically analysed by means of the computer model. The analysed protection methods are based either upon application on a structure surface of a reflective layer, or covering it with a protective layer made of a very porous concrete or an addition of the PP fibres to the concrete mix. Efficiency of these methods has been numerically analysed in thermal conditions corresponding to the ISO-834 standard fire. The results obtained show that even relatively simple methods, like application a protective layer or increasing the surface reflectance, can retard to some extent concrete degradation during a fire.

  5. Critical elements in the development and implementation of Community Wildfire Protection Plans (CWPPs)

    Treesearch

    Pamela Jakes; Sam Burns; Antony Cheng; Emily Saeli; Kristen Nelson Rachel Brummel; Stephanie Grayzeck; Victoria Sturtevant; Daniel Williams

    2007-01-01

    Community wildfire protection plans (CWPPs) are being developed and implemented in communities across the United States. In a series of case studies, researchers found that the process of developing a CWPP can lead to benefits beyond those associated with fuels reduction, including enhancing social networks, developing learning communities, and building community...

  6. Genetic Interactions Between P Elements Involved in piRNA-Mediated Repression of Hybrid Dysgenesis in Drosophila melanogaster

    PubMed Central

    Simmons, Michael J.; Meeks, Marshall W.; Jessen, Erik; Becker, Jordan R.; Buschette, Jared T.; Thorp, Michael W.

    2014-01-01

    Previous studies have shown that telomeric P elements inserted at the left end of the X chromosome are anchors of the P cytotype, the maternally inherited state that regulates P-element activity in the germ line of Drosophila melanogaster. This regulation is mediated by small RNAs that associate with the Piwi family of proteins (piRNAs). We extend the analysis of cytotype regulation by studying new combinations of telomeric and nontelomeric P elements (TPs and non-TPs). TPs interact with each other to enhance cytotype regulation. This synergism involves a strictly maternal effect, called presetting, which is apparently mediated by piRNAs transmitted through the egg. Presetting by a maternal TP can elicit regulation by an inactive paternally inherited TP, possibly by stimulating its production of primary piRNAs. When one TP has come from a stock heterozygous for a mutation in the aubergine, piwi, or Suppressor of variegation 205 genes, the synergism between two TPs is impaired. TPs also interact with non-TPs to enhance cytotype regulation, even though the non-TPs lack regulatory ability on their own. Non-TPs are not susceptible to presetting by a TP, nor is a TP susceptible to presetting by a non-TP. The synergism between TPs and non-TPs is stronger when the TP was inherited maternally. This synergism may be due to the accumulation of secondary piRNAs created by ping-pong cycling between primary piRNAs from the TPs and mRNAs from the non-TPs. Maternal transmission of P-element piRNAs plays an important role in the maintenance of strong cytotype regulation over generations. PMID:24902606

  7. ATP protects, by way of receptor-mediated mechanisms, against hypoxia-induced injury in renal proximal tubules.

    PubMed

    Kribben, Andreas; Feldkamp, Thorsten; Horbelt, Markus; Lange, Bettina; Pietruck, Frank; Herget-Rosenthal, Stefan; Heemann, Uwe; Philipp, Thomas

    2003-01-01

    We examined the effect of ATP on hypoxia-induced injury in freshly isolated rat renal proximal tubules and compared it with the effects of stable ATP analogues and ATP degradation products. Extracellular ATP significantly reduced hypoxia-induced structural cell damage (lactate dehydrogenase release). P(2)-receptor agonistic ATP analogues, including 2'-methylthio-ATP (2-Me-S-ATP), were also protective. In contrast, the P(1)-agonistic degradation products AMP and adenosine were not protective. Hypoxia-induced functional cell damage (loss of cellular potassium) was not changed by ATP or 2-Me-S-ATP. We therefore conclude that the protective property of ATP is not based on an effect of the degradation products or on a direct effect on cellular energy metabolism. The data indicate that the protective effect of ATP is mediated by P(2) receptors.

  8. Levels, spatial variation and compartmentalization of trace elements in brown algae Cystoseira from marine protected areas of Crimea (Black Sea).

    PubMed

    Kravtsova, Alexandra V; Milchakova, Nataliya A; Frontasyeva, Marina V

    2015-08-15

    Levels of Al, Sc, V, Co, Ni, As, Br, Rb, Sr, Ag, Sb, I, Cs, Ba, Th and U that were rarely or never studied, as well as the concentrations of classically investigated Mn, Fe and Zn in brown algae Cystoseira barbata C. Ag. and Cystoseira crinita (Desf.) Bory from the coastal waters of marine protected areas (Crimea, Black Sea), were determined using neutron activation analysis. Spatial variation and compartmentalization were studied for all 19 trace elements (TE). Concentrations of most TE were higher in "branches" than in "stems". Spatial variations of V, Co, Ni and Zn can be related to anthropogenic activities while Al, Sc, Fe, Rb, Cs, Th and U varied depending on chemical peculiarities of the coastal zone rocks. TE concentrations in C. crinita from marine protected areas near Tarkhankut peninsula and Cape Fiolent, identified as the most clean water areas, are submitted as the background concentrations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. On the transfer of protective coating elements on a metal surface from halide gaseous media

    NASA Astrophysics Data System (ADS)

    Abraimov, N. V.

    2016-06-01

    The processes occurring during the formation of multicomponent diffusion coatings on nickel alloys at the stage of delivery of elements on the article surface when chlorine, bromine, and iodine halides are used as activators are considered. Balance equations and calculated values are given for the partial pressures in the composition of a gas phase of components participating in chemical transport reaction; the possible reactions of delivering elements on the article surfaces and the structures of Ni-Al, Ni-Cr, Ni-Cr-Al, Co-Cr-Al coatings deposited on the ZhS26, ZhS6U, ZhS32, and VZhL12U alloys are presented.

  10. Mps1 kinase-dependent Sgo2 centromere localisation mediates cohesin protection in mouse oocyte meiosis I.

    PubMed

    El Yakoubi, Warif; Buffin, Eulalie; Cladière, Damien; Gryaznova, Yulia; Berenguer, Inés; Touati, Sandra A; Gómez, Rocío; Suja, José A; van Deursen, Jan M; Wassmann, Katja

    2017-09-25

    A key feature of meiosis is the step-wise removal of cohesin, the protein complex holding sister chromatids together, first from arms in meiosis I and then from the centromere region in meiosis II. Centromeric cohesin is protected by Sgo2 from Separase-mediated cleavage, in order to maintain sister chromatids together until their separation in meiosis II. Failures in step-wise cohesin removal result in aneuploid gametes, preventing the generation of healthy embryos. Here, we report that kinase activities of Bub1 and Mps1 are required for Sgo2 localisation to the centromere region. Mps1 inhibitor-treated oocytes are defective in centromeric cohesin protection, whereas oocytes devoid of Bub1 kinase activity, which cannot phosphorylate H2A at T121, are not perturbed in cohesin protection as long as Mps1 is functional. Mps1 and Bub1 kinase activities localise Sgo2 in meiosis I preferentially to the centromere and pericentromere respectively, indicating that Sgo2 at the centromere is required for protection.In meiosis I centromeric cohesin is protected by Sgo2 from Separase-mediated cleavage ensuring that sister chromatids are kept together until their separation in meiosis II. Here the authors demonstrate that Bub1 and Mps1 kinase activities are required for Sgo2 localisation to the centromere region.

  11. Human CD8+ T cells mediate protective immunity induced by a human malaria vaccine in human immune system mice.

    PubMed

    Li, Xiangming; Huang, Jing; Zhang, Min; Funakoshi, Ryota; Sheetij, Dutta; Spaccapelo, Roberta; Crisanti, Andrea; Nussenzweig, Victor; Nussenzweig, Ruth S; Tsuji, Moriya

    2016-08-31

    A number of studies have shown that CD8+ T cells mediate protective anti-malaria immunity in a mouse model. However, whether human CD8+ T cells play a role in protection against malaria remains unknown. We recently established human immune system (HIS) mice harboring functional human CD8+ T cells (HIS-CD8 mice) by transduction with HLA-A∗0201 and certain human cytokines using recombinant adeno-associated virus-based gene transfer technologies. These HIS-CD8 mice mount a potent, antigen-specific HLA-A∗0201-restricted human CD8+ T-cell response upon immunization with a recombinant adenovirus expressing a human malaria antigen, the Plasmodium falciparum circumsporozoite protein (PfCSP), termed AdPfCSP. In the present study, we challenged AdPfCSP-immunized HIS-CD8 mice with transgenic Plasmodium berghei sporozoites expressing full-length PfCSP and found that AdPfCSP-immunized (but not naïve) mice were protected against subsequent malaria challenge. The level of the HLA-A∗0201-restricted, PfCSP-specific human CD8+ T-cell response was closely correlated with the level of malaria protection. Furthermore, depletion of human CD8+ T cells from AdPfCSP-immunized HIS-CD8 mice almost completely abolished the anti-malaria immune response. Taken together, our data show that human CD8+ T cells mediate protective anti-malaria immunity in vivo.

  12. Positive and negative regulatory elements mediating transcription from the Drosophila melanogaster actin 5C distal promoter.

    PubMed Central

    Chung, Y T; Keller, E B

    1990-01-01

    The major cytoskeletal actin gene of Drosophila melanogaster, the actin 5C gene, has two promoters, the distal one of which controls synthesis of actin in a tissue- and developmental stage-specific manner. This very strong promoter has widely been used for expression of heterologous genes in cultured cells. To locate functional regulatory elements in this distal promoter, mutants of the promoter were fused to the bacterial chloramphenicol acetyltransferase gene and assayed for transient expression activity in cultured Drosophila embryonic Schneider line 2 cells. The results showed that the upstream end of the promoter extends to 522 bp from the transcription start site. In addition, there are two remote activating regions about 2 kb upstream. Between -522 and -379 are two regions that exert a strong negative effect. Downstream from these negative regions are at least six positive regions and a TATA element. The strongest positive determinant of the promoter was identified at -320 as AAAATGTG by footprinting and by a replacement experiment. When the relevant region was replaced by a synthetic sequence containing this element in a random context, the transient expression activity was restored. The sequence TGTATG located at -355 was also identified as a positive element by a similar replacement approach. Apparently the very high activity of this promoter is the result of the combined activities of multiple factors. Images PMID:2123290

  13. Protection mediated by chemokine CXCL10 in BALB/c mice infected by Leishmania infantum.

    PubMed

    Figueiredo, Webertty Mayk Eufrásio; Viana, Sayonara de Melo; Alves, Dorotheia Teixeira; Guerra, Priscila Valera; Coêlho, Zirlane Castelo Branco; Barbosa, Helene Santos; Teixeira, Maria Jania

    2017-08-01

    Visceral leishmaniasis (VL) caused by Leishmania infantum is characterised by the loss of the ability of the host to generate an effective immune response. Chemokines have a direct involvement in the pathogenesis of leishmaniasis, causing a rapid change in the expression of these molecules during infection by Leishmania. Herein, it was investigated the role of CXCL10 in controlling infection by L. infantum. RAW 264.7 macrophages were infected with L. infantum in vitro and treated or not with CXCL10 (25, 50 and 100 ng/mL). Parasite load, as well as nitric oxide (NO), IL-4 and IL-10 production were assessed at 24 and 48 h after infection. In vivo, BALB/c mice were infected and treated or not with CXCL10 (5 μg/kg) at one, three and seven days of infection. Parasite load, IFN-g, IL-4, TGF-β and IL-10 were evaluated one, seven and 23 days post treatment. In vitro, CXCL10 reduced parasitic load, not dependent on NO, and inhibited IL-10 and IL-4 secretion. In vivo, CXCL10 was able to reduce the parasite load in both liver and spleen, four weeks after infection, representing a higher decrease in the number of parasites in these organs, also induced IFN-γ at day 23 after treatment, correlating with the decrease in parasite load, and reduced IL-10 and TGF-β. This study suggests a partial protective role of CXCL10 against L. infantum, mediated by IFN-g, not dependent on NO, and with suppression of IL-10 and TGF-β. These data may provide information for the development of new approaches for future therapeutic interventions for VL.

  14. TAT-Mediated Delivery of Tousled Protein to Salivary Glands Protects Against Radiation-Induced Hypofunction

    SciTech Connect

    Sunavala-Dossabhoy, Gulshan; Palaniyandi, Senthilnathan; Richardson, Charles; De Benedetti, Arrigo; Schrott, Lisa; Caldito, Gloria

    2012-09-01

    Purpose: Patients treated with radiotherapy for head-and-neck cancer invariably suffer its deleterious side effect, xerostomia. Salivary hypofunction ensuing from the irreversible destruction of glands is the most common and debilitating oral complication affecting patients undergoing regional radiotherapy. Given that the current management of xerostomia is palliative and ineffective, efforts are now directed toward preventive measures to preserve gland function. The human homolog of Tousled protein, TLK1B, facilitates chromatin remodeling at DNA repair sites and improves cell survival against ionizing radiation (IR). Therefore, we wanted to determine whether a direct transfer of TLK1B protein to rat salivary glands could protect against IR-induced salivary hypofunction. Methods: The cell-permeable TAT-TLK1B fusion protein was generated. Rat acinar cell line and rat salivary glands were pretreated with TAT peptide or TAT-TLK1B before IR. The acinar cell survival in vitro and salivary function in vivo were assessed after radiation. Results: We demonstrated that rat acinar cells transduced with TAT-TLK1B were more resistant to radiation (D{sub 0} = 4.13 {+-} 1.0 Gy; {alpha}/{beta} = 0 Gy) compared with cells transduced with the TAT peptide (D{sub 0} = 4.91 {+-} 1.0 Gy; {alpha}/{beta} = 20.2 Gy). Correspondingly, retroductal instillation of TAT-TLK1B in rat submandibular glands better preserved salivary flow after IR (89%) compared with animals pretreated with Opti-MEM or TAT peptide (31% and 39%, respectively; p < 0.01). Conclusions: The results demonstrate that a direct transfer of TLK1B protein to the salivary glands effectively attenuates radiation-mediated gland dysfunction. Prophylactic TLK1B-protein therapy could benefit patients undergoing radiotherapy for head-and-neck cancer.

  15. Protection mediated by chemokine CXCL10 in BALB/c mice infected by Leishmania infantum

    PubMed Central

    Figueiredo, Webertty Mayk Eufrásio; Viana, Sayonara de Melo; Alves, Dorotheia Teixeira; Guerra, Priscila Valera; Coêlho, Zirlane Castelo Branco; Barbosa, Helene Santos; Teixeira, Maria Jania

    2017-01-01

    BACKGROUND Visceral leishmaniasis (VL) caused by Leishmania infantum is characterised by the loss of the ability of the host to generate an effective immune response. Chemokines have a direct involvement in the pathogenesis of leishmaniasis, causing a rapid change in the expression of these molecules during infection by Leishmania. OBJECTIVES Herein, it was investigated the role of CXCL10 in controlling infection by L. infantum. METHODS RAW 264.7 macrophages were infected with L. infantum in vitro and treated or not with CXCL10 (25, 50 and 100 ng/mL). Parasite load, as well as nitric oxide (NO), IL-4 and IL-10 production were assessed at 24 and 48 h after infection. In vivo, BALB/c mice were infected and treated or not with CXCL10 (5 μg/kg) at one, three and seven days of infection. Parasite load, IFN-g, IL-4, TGF-β and IL-10 were evaluated one, seven and 23 days post treatment. FINDINGS In vitro, CXCL10 reduced parasitic load, not dependent on NO, and inhibited IL-10 and IL-4 secretion. In vivo, CXCL10 was able to reduce the parasite load in both liver and spleen, four weeks after infection, representing a higher decrease in the number of parasites in these organs, also induced IFN-γ at day 23 after treatment, correlating with the decrease in parasite load, and reduced IL-10 and TGF-β. MAIN CONCLUSIONS This study suggests a partial protective role of CXCL10 against L. infantum, mediated by IFN-g, not dependent on NO, and with suppression of IL-10 and TGF-β. These data may provide information for the development of new approaches for future therapeutic interventions for VL. PMID:28767981

  16. The Bordetella pertussis Bps Polysaccharide Enhances Lung Colonization by Conferring Protection from Complement-mediated Killing

    PubMed Central

    Ganguly, Tridib; Johnson, John B.; Kock, Nancy D.; Parks, Griffith D.; Deora, Rajendar

    2014-01-01

    Summary Bordetella pertussis is a human-restricted Gram-negative bacterial pathogen that causes whooping cough or pertussis. Pertussis is the leading vaccine preventable disease that is resurging in the USA and other parts of the developed world. There is an incomplete understanding of the mechanisms by which B. pertussis evades killing and clearance by the complement system, a first line of host innate immune defense. The present study examined the role of the Bps polysaccharide to resist complement activity in vitro and in the mouse respiratory tract. The isogenic bps mutant strain containing a large non polar in-frame deletion of the bpsA-D locus was more sensitive to serum and complement mediated killing than the WT strain. As determined by western blotting, flow cytometry and electron microscopic studies, the heightened sensitivity of the mutant strain was due to enhanced deposition of complement proteins and the formation of membrane attack complex, the end product of complement activation. Bps was sufficient to confer complement resistance as evidenced by a Bps-expressing E. coli being protected by serum killing. Additionally, western blotting and flow cytometry assays revealed that Bps inhibited the deposition of complement proteins independent of other B. pertussis factors. The bps mutant strain colonized the lungs of complement-deficient mice at higher levels than that observed in C57Bl/6 mice. These results reveal a previously unknown interaction between Bps and the complement system in controlling B. pertussis colonization of the respiratory tract. These findings also make Bps a potential target for the prevention and therapy of whooping cough. PMID:24438122

  17. Ursolic Acid Mediates Hepatic Protection through Enhancing of anti-aging Biomarkers.

    PubMed

    Gharibi, Shadi; Bakhtiari, Nuredin; Jalalvand, Elham-Moslemee

    2017-05-30

    Age-associated loss of liver function has been recognized for decades. But, the mechanism driving liver regeneration and its decline with age remains elusive. Hence, to support of our previous studies about anti-aging effects of Ursolic Acid (UA), a compound which extensively present in apple peels. The aim of this study is to address whether UA might alter sensors of the cell metabolic state such as SIRT1, SIRT6, PGC-1β and Klotho proteins. To evaluate the effect of UA on hepatic indicated proteins, mice were administrated with UA twice daily for 7 days. The involvements of these proteins in the UA-mediated effect harmony hepatic protection were investigated by immunofluorescence microscopy technique. Our findings clearly illustrated that UA enhanced SIRT1 (~ 5 ± 0.2 folds) and SIRT6 (~ 8 ± 0.5 folds) proteins levels in hepatic, p<0.001. In addition, the data showed that UA increased PGC-1β (~ 7 ± 0.4 folds) protein overexpression, p<0.001. Moreover, we showed that UA up-regulated Klotho (~ 3.5 ± 0.2 folds) protein in order to improve hepatic performance, p<0.01. Our results suggest that UA through increasing of SIRT1 up-regulation ameliorate reverse cholesterol transport, fatty acid use and oxidative stress defense. In addition, it seems that UA by enhancing of SIRT6 expression promotes cholesterol homeostasis through repressing of SREBP1 and SREBP2. Reciprocally, UA might be involved in VLDL synthesis and exportation through PGC-1β up-regulation. Finally, UA might be as key regulators of mineral homeostasis and bile acid/cholesterol metabolism, by inducing of Klotho overexpression. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  18. Rupatadine Protects against Pulmonary Fibrosis by Attenuating PAF-Mediated Senescence in Rodents

    PubMed Central

    Lv, Xiao-xi; Wang, Xiao-xing; Li, Ke; Wang, Zi-yan; Li, Zhe; Lv, Qi; Fu, Xiao-ming; Hu, Zhuo-Wei

    2013-01-01

    A similar immune response is implicated in the pathogenesis of pulmonary fibrosis and allergic disorders. We investigated the potential therapeutic efficacy and mechanism of rupatadine, a dual antagonist of histamine and platelet-activation factor (PAF), in bleomycin- (BLM-) and silica-induced pulmonary fibrosis. The indicated dosages of rupatadine were administered in rodents with bleomycin or silica-induced pulmonary fibrosis. The tissue injury, fibrosis, inflammatory cells and cytokines, and lung function were examined to evaluate the therapeutic efficacy of rupatadine. The anti-fibrosis effect of rupatadine was compared with an H1 or PAF receptor antagonist, and efforts were made to reveal rupatadine’s anti-fibrotic mechanism. Rupatadine promoted the resolution of pulmonary inflammation and fibrosis in a dose-dependent manner, as indicated by the reductions in inflammation score, collagen deposition and epithelial-mesenchymal transformation, and infiltration or expression of inflammatory cells or cytokines in the fibrotic lung tissue. Thus, rupatadine treatment improved the declined lung function and significantly decreased animal death. Moreover, rupatadine was able not only to attenuate silica-induced silicosis but also to produce a superior therapeutic efficacy compared to pirfenidone, histamine H1 antagonist loratadine, or PAF antagonist CV-3988. The anti-fibrotic action of rupatadine might relate to its attenuation of BLM- or PAF-induced premature senescence because rupatadine treatment protected against the in vivo and in vitro activation of the p53/p21-dependent senescence pathway. Our studies indicate that rupatadine promotes the resolution of pulmonary inflammation and fibrosis by attenuating the PAF-mediated senescence response. Rupatadine holds promise as a novel drug to treat the devastating disease of pulmonary fibrosis. PMID:23869224

  19. Nanoparticles modulate surfactant protein A and D mediated protection against influenza A infection in vitro

    PubMed Central

    McKenzie, Zofi; Kendall, Michaela; Mackay, Rose-Marie; Tetley, Teresa D.; Morgan, Cliff; Griffiths, Mark; Clark, Howard W.; Madsen, Jens

    2015-01-01

    Numerous epidemiological and toxicological studies have indicated that respiratory infections are exacerbated following enhanced exposure to airborne particulates. Surfactant protein A (SP-A) and SP-D form an important part of the innate immune response in the lung and can interact with nanoparticles to modulate the cellular uptake of these particles. We hypothesize that this interaction will also affect the ability of these proteins to combat infections. TT1, A549 and differentiated THP-1 cells, representing the predominant cell types found in the alveolus namely alveolar type I (ATI) epithelial cells, ATII cells and macrophages, were used to examine the effect of two model nanoparticles, 100 nm amine modified (A-PS) and unmodified polystyrene (U-PS), on the ability of SP-A and SP-D to neutralize influenza A infections in vitro. Pre-incubation of low concentrations of U-PS with SP-A resulted in a reduction of SP-A anti-influenza activity in A549 cells, whereas at higher concentrations there was an increase in SP-A antiviral activity. This differential pattern of U-PS concentration on surfactant protein mediated protection against IAV was also shown with SP-D in TT1 cells. On the other hand, low concentrations of A-PS particles resulted in a reduction of SP-A activity in TT1 cells and a reduction in SP-D activity in A549 cells. These results indicate that nanoparticles can modulate the ability of SP-A and SP-D to combat viral challenges. Furthermore, the nanoparticle concentration, surface chemistry and cell type under investigation are important factors in determining the extent of these modulations. PMID:25533100

  20. EGFR mediates astragaloside IV-induced Nrf2 activation to protect cortical neurons against in vitro ischemia/reperfusion damages

    SciTech Connect

    Gu, Da-min; Lu, Pei-Hua; Zhang, Ke; Wang, Xiang; Sun, Min; Chen, Guo-Qian; Wang, Qiong

    2015-02-13

    In this study, we tested the potential role of astragaloside IV (AS-IV) against oxygen and glucose deprivation/re-oxygenation (OGD/R)-induced damages in murine cortical neurons, and studied the associated signaling mechanisms. AS-IV exerted significant neuroprotective effects against OGD/R by reducing reactive oxygen species (ROS) accumulation, thereby attenuating oxidative stress and neuronal cell death. We found that AS-IV treatment in cortical neurons resulted in NF-E2-related factor 2 (Nrf2) signaling activation, evidenced by Nrf2 Ser-40 phosphorylation, and its nuclear localization, as well as transcription of antioxidant-responsive element (ARE)-regulated genes: heme oxygenase-1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO-1) and sulphiredoxin 1 (SRXN-1). Knockdown of Nrf2 through lentiviral shRNAs prevented AS-IV-induced ARE genes transcription, and abolished its anti-oxidant and neuroprotective activities. Further, we discovered that AS-IV stimulated heparin-binding-epidermal growth factor (HB-EGF) release to trans-activate epidermal growth factor receptor (EGFR) in cortical neurons. Blockage or silencing EGFR prevented Nrf2 activation by AS-IV, thus inhibiting AS-IV-mediated anti-oxidant and neuroprotective activities against OGD/R. In summary, AS-IV protects cortical neurons against OGD/R damages through activating of EGFR-Nrf2 signaling. - Highlights: • Pre-treatment of astragaloside IV (AS-IV) protects murine cortical neurons from OGD/R. • AS-IV activates Nrf2-ARE signaling in murine cortical neurons. • Nrf2 is required for AS-IV-mediated anti-oxidant and neuroprotective activities. • AS-IV stimulates HB-EGF release to trans-activate EGFR in murine cortical neurons. • EGFR mediates AS-IV-induced Nrf2 activation and neuroprotection against OGD/R.

  1. Ethanol activates cAMP response element-mediated gene expression in select regions of the mouse brain.

    PubMed

    Asyyed, Asma; Storm, Daniel; Diamond, Ivan

    2006-08-23

    The specific brain regions that contribute to behavioral changes produced by ethanol are not clearly understood. We know that cAMP-PKA signaling has been strongly implicated in the CNS effects of ethanol. Ethanol promotes activation and translocation of the PKA catalytic subunit (Calpha) into the nucleus in cell lines and primary neuronal cultures. PKA Calpha translocation to the nucleus is followed by cAMP Response Element protein phosphorylation (pCREB) and cAMP Response Element (CRE)-mediated gene expression. Here, we use X-gal histochemistry to map CRE-mediated gene transcription in the brain of CRE-lacZ transgenic mice following ethanol injection. 3 h after i.p. ethanol injection (3.2 g/kg, 16% wt/vol.), the number of X-gal positive cells was increased in the nucleus accumbens (202 +/- 63 cells/field compared to 71 +/- 47 cells/field in saline injected controls, P < 0.05 by paired t-test, n = 10). Similar increases were found in other mesolimbic areas and brain regions associated with rewarding and addictive responses. These include: prefrontal cortex, lateral and medial septum, basolateral amygdala, paraventricular and anterior hypothalamus, centromedial thalamus, CA1 region of hippocampus and dentate gyrus, substantia nigra pars compacta, ventral tegmental area, geniculate nucleus and the superior colliculus. these results confirm and extend current concepts that ethanol stimulates cAMP-PKA signaling in brain regions involved in CNS responses to ethanol.

  2. The Role of piRNA-Mediated Epigenetic Silencing in the Population Dynamics of Transposable Elements in Drosophila melanogaster

    PubMed Central

    Lee, Yuh Chwen G.

    2015-01-01

    The piwi-interacting RNAs (piRNA) are small RNAs that target selfish transposable elements (TEs) in many animal genomes. Until now, piRNAs’ role in TE population dynamics has only been discussed in the context of their suppression of TE transposition, which alone is not sufficient to account for the skewed frequency spectrum and stable containment of TEs. On the other hand, euchromatic TEs can be epigenetically silenced via piRNA-dependent heterochromatin formation and, similar to the widely known “Position-effect variegation”, heterochromatin induced by TEs can “spread” into nearby genes. We hypothesized that the piRNA-mediated spread of heterochromatin from TEs into adjacent genes has deleterious functional effects and leads to selection against individual TEs. Unlike previously identified deleterious effects of TEs due to the physical disruption of DNA, the functional effect we investigated here is mediated through the epigenetic influences of TEs. We found that the repressive chromatin mark, H3K9me, is elevated in sequences adjacent to euchromatic TEs at multiple developmental stages in Drosophila melanogaster. Furthermore, the heterochromatic states of genes depend not only on the number of and distance from adjacent TEs, but also on the likelihood that their nearest TEs are targeted by piRNAs. These variations in chromatin status probably have functional consequences, causing genes near TEs to have lower expression. Importantly, we found stronger selection against TEs that lead to higher H3K9me enrichment of adjacent genes, demonstrating the pervasive evolutionary consequences of TE-induced epigenetic silencing. Because of the intrinsic biological mechanism of piRNA amplification, spread of TE heterochromatin could result in the theoretically required synergistic deleterious effects of TE insertions for stable containment of TE copy number. The indirect deleterious impact of piRNA-mediated epigenetic silencing of TEs is a previously unexplored, yet

  3. Hearing Protection for High-Noise Environments. Part 2: Finite Element Modeling

    DTIC Science & Technology

    2007-05-31

    elimination is stopped before processing fake ele- ments. Sub-domain internal nodes are eliminated ......... 37 22 Global interface problem can be... fake elements. Sub-domain internal nodes are eliminated. Pi (i) •(i) • / ()•• C5 PbM tinternal X "interface) M i niner)c x in(t)e)rfCe) Pbb :M (niner...AiA’ = Pb (C.9) 37 FN- Figure 22: Global interface problem can be aggregated by summing up local Schur complements. Ai =A - CiA:’ BT (C.10) bi b’ - CiA

  4. Numerical Simulation of a Thermal-Protection Element of a Promising Reusable Capsule-Type Lander

    NASA Astrophysics Data System (ADS)

    Prosuntsov, P. V.; Shulyakovskii, A. V.; Taraskin, N. Yu.

    2017-01-01

    An indestructible multilayer thermal-barrier coating is proposed for a promising reusable capsule-type lander. This coating is based on a porous carbon-ceramic material. The thermal state of the coating proposed was simulated mathematically for different types of its reinforcement and different values of the porosity and the heat-conductivity coefficient of the carbon-ceramic material. Results of a numerical simulation of the temperature state of an element of the multilayer thermal-barrier coating are presented. On the basis of these data, the thickness and the weight efficiency of the coating were estimated.

  5. Hard protective waterproof coating for high-power laser optical elements.

    PubMed

    Murahara, Masataka; Sato, Nobuhiro; Ikadai, Akimitsu

    2005-12-15

    We developed a new method for making a waterproof coating by photooxidation of silicone oil. The silicone oil was spin coated onto the surfaces of optical elements, i.e., a plastic lens, a laser mirror, and a nonlinear optical crystal, and then irradiated with a xenon excimer lamp in air, which transformed the organic silicone oil into an amorphous glass film. This technique has enabled an optical thin film to transmit ultraviolet rays of wavelengths below 200 nm and to exhibit the characteristics of homogeneity, high density, and resistance to environmental effects and to corrosion by water, and a Mohs scale value of 5.

  6. A pineal regulatory element (PIRE) mediates transactivation by the pineal/retina-specific transcription factor CRX.

    PubMed

    Li, X; Chen, S; Wang, Q; Zack, D J; Snyder, S H; Borjigin, J

    1998-02-17

    The circadian hormone melatonin is synthesized predominantly in the pineal gland by the actions of two pineal-specific enzymes: serotonin N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT). Pineal night-specific ATPase (PINA), another pineal- and night-specific protein we recently identified, is produced as a truncated form of the Wilson disease gene (Atp7b) product. To identify the regulatory elements required for pineal-specific gene expression, we isolated sequences upstream of the rat PINA gene and discovered a cis-acting element that is recognized by a novel pineal/retina-specific nuclear factor. This pineal regulatory element (PIRE) has a consensus of TAATC/T and is present in six copies in the 5' regulatory region of the PINA gene, at least three copies in the rat NAT promoter, and at least one copy in each of the putative HIOMT promoters A and B. A recently identified retina-specific protein, cone rod homeobox (CRX), binds to PIRE in vitro and transactivates PIRE-reporter constructs. These data suggest that Crx may play a crucial role in regulating pineal gene expression through interactions with PIRE.

  7. A pineal regulatory element (PIRE) mediates transactivation by the pineal/retina-specific transcription factor CRX

    PubMed Central

    Li, Xiaodong; Chen, Shiming; Wang, Qingliang; Zack, Donald J.; Snyder, Solomon H.; Borjigin, Jimo

    1998-01-01

    The circadian hormone melatonin is synthesized predominantly in the pineal gland by the actions of two pineal-specific enzymes: serotonin N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT). Pineal night-specific ATPase (PINA), another pineal- and night-specific protein we recently identified, is produced as a truncated form of the Wilson disease gene (Atp7b) product. To identify the regulatory elements required for pineal-specific gene expression, we isolated sequences upstream of the rat PINA gene and discovered a cis-acting element that is recognized by a novel pineal/retina-specific nuclear factor. This pineal regulatory element (PIRE) has a consensus of TAATC/T and is present in six copies in the 5′ regulatory region of the PINA gene, at least three copies in the rat NAT promoter, and at least one copy in each of the putative HIOMT promoters A and B. A recently identified retina-specific protein, cone rod homeobox (CRX), binds to PIRE in vitro and transactivates PIRE-reporter constructs. These data suggest that Crx may play a crucial role in regulating pineal gene expression through interactions with PIRE. PMID:9465110

  8. SIRT3 protects cardiomyocytes from oxidative stress-mediated cell death by activating NF-κB.

    PubMed

    Chen, Chun-Juan; Fu, Yu-Cai; Yu, Wei; Wang, Wei

    2013-01-11

    Oxidative stress-mediated cell death in cardiomyocytes reportedly plays an important role in many cardiac pathologies. Our previous report demonstrated that mitochondrial SIRT3 plays an essential role in mediating cell survival in cardiac myocytes, and that resveratrol protects cardiomyocytes from oxidative stress-induced apoptosis by activating SIRT3. However, the exact mechanism by which SIRT3 prevents oxidative stress remains unknown. Here, we show that exposure of H9c2 cells to 50 μM H(2)O(2) for 6h caused a significant increase in cell death and the down-regulation of SIRT3. Reactive oxygen species (ROS)-mediated NF-κB activation was involved in this SIRT3 down-regulation. The SIRT3 activator, resveratrol, which is considered an important antioxidant, protected against H(2)O(2)-induced cell death, whereas the SIRT inhibitor, nicotinamide, enhanced cell death. Moreover, resveratrol negatively regulated H(2)O(2)-induced NF-κB activation, whereas nicotinamide enhanced H(2)O(2)-induced NF-κB activation. We also found that SOD2, Bcl-2 and Bax, the downstream genes of NF-κB, were involved in this pathological process. These results suggest that SIRT3 protects cardiomyocytes exposed to oxidative stress from apoptosis via a mechanism that may involve the NF-κB pathway. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Mouse CD4+ CD25+ T regulatory cells are protected from autologous complement mediated injury by Crry and CD59

    PubMed Central

    Li, Qing; Nacion, Kristine; Bu, Hong; Lin, Feng

    2009-01-01

    Self cells depend on surface complement regulators to protect them from autologous complement-mediated attack. CD4+CD25+foxp3+ T regulatory (Treg) cells are critical in maintaining immune homeostasis, however, which complement regulators are expressed on them and how they are protected from autologous complement attack remains unknown. We report here that mouse Treg cells express virtually no DAF or CR1. Instead, all of them express Crry and approximately half of them express CD59. Both Crry-/- and CD59-/- Treg cells exhibit greater complement mediated injury than WT Treg cells. These results clarify the status of cell surface complement regulators on mouse Treg cells and indicate that both Crry and CD59 are required to protect Treg cells from autologous complement-mediated injury. Additionally, these data also argue that different from previous assumption, at least in mice, CD4+CD25+foxp3+ Treg cells are not homogenous and could be further divided into subgroups based on CD59 expression. PMID:19281793

  10. Mouse CD4+ CD25+ T regulatory cells are protected from autologous complement mediated injury by Crry and CD59.

    PubMed

    Li, Qing; Nacion, Kristine; Bu, Hong; Lin, Feng

    2009-04-24

    Self cells depend on surface complement regulators to protect them from autologous complement mediated attack. CD4(+)CD25(+)foxp3(+) T regulatory (Treg) cells are critical in maintaining immune homeostasis, however, which complement regulators are expressed on them and how they are protected from autologous complement attack remains unknown. We report here that mouse Treg cells express virtually no DAF or CR1. Instead, all of them express Crry and approximately half of them express CD59. Both Crry(-/-) and CD59(-/-) Treg cells exhibit greater complement mediated injury than WT Treg cells. These results clarify the status of cell surface complement regulators on mouse Treg cells and indicate that both Crry and CD59 are required to protect Treg cells from autologous complement mediated injury. Additionally, these data also argue that different from previous assumption, at least in mice, CD4(+)CD25(+)foxp3(+) Treg cells are not homogenous and could be further divided into subgroups based on CD59 expression.

  11. Abscisic acid-induced gene expression in the liverwort Marchantia polymorpha is mediated by evolutionarily conserved promoter elements.

    PubMed

    Ghosh, Totan K; Kaneko, Midori; Akter, Khaleda; Murai, Shuhei; Komatsu, Kenji; Ishizaki, Kimitsune; Yamato, Katsuyuki T; Kohchi, Takayuki; Takezawa, Daisuke

    2016-04-01

    Abscisic acid (ABA) is a phytohormone widely distributed among members of the land plant lineage (Embryophyta), regulating dormancy, stomata closure and tolerance to environmental stresses. In angiosperms (Magnoliophyta), ABA-induced gene expression is mediated by promoter elements such as the G-box-like ACGT-core motifs recognized by bZIP transcription factors. In contrast, the mode of regulation by ABA of gene expression in liverworts (Marchantiophyta), representing one of the earliest diverging land plant groups, has not been elucidated. In this study, we used promoters of the liverwort Marchantia polymorpha dehydrin and the wheat Em genes fused to the β-glucuronidase (GUS) reporter gene to investigate ABA-induced gene expression in liverworts. Transient assays of cultured cells of Marchantia indicated that ACGT-core motifs proximal to the transcription initiation site play a role in the ABA-induced gene expression. The RY sequence recognized by B3 transcriptional regulators was also shown to be responsible for the ABA-induced gene expression. In transgenic Marchantia plants, ABA treatment elicited an increase in GUS expression in young gemmalings, which was abolished by simultaneous disruption of the ACGT-core and RY elements. ABA-induced GUS expression was less obvious in mature thalli than in young gemmalings, associated with reductions in sensitivity to exogenous ABA during gametophyte growth. In contrast, lunularic acid, which had been suggested to function as an ABA-like substance, had no effect on GUS expression. The results demonstrate the presence of ABA-specific response mechanisms mediated by conserved cis-regulatory elements in liverworts, implying that the mechanisms had been acquired in the common ancestors of embryophytes. © 2015 Scandinavian Plant Physiology Society.

  12. Effect of endogenous androgens on 17beta-estradiol-mediated protection after spinal cord injury in male rats.

    PubMed

    Kachadroka, Supatra; Hall, Alicia M; Niedzielko, Tracy L; Chongthammakun, Sukumal; Floyd, Candace L

    2010-03-01

    Several groups have recently shown that 17beta-estradiol is protective in spinal cord injury (SCI). Testosterone can be aromatized to 17beta-estradiol and may increase estrogen-mediated protection. Alternatively, testosterone has been shown to increase excitotoxicity in models of central nervous system (CNS) injury. These experiments test the hypothesis that endogenous testosterone in male rats alters 17beta-estradiol-mediated protection by evaluating a delayed administration over a clinically relevant dose range and manipulating testicular-derived testosterone. Adult male Sprague Dawley rats were either gonadectomized or left gonad-intact prior to SCI. SCI was produced by a midthoracic crush injury. At 30 min post SCI, animals received a subcutaneous pellet of 0.0, 0.05, 0.5, or 5.0 mg of 17beta-estradiol, released over 21 days. Hindlimb locomotion was analyzed weekly in the open field. Spinal cords were collected and analyzed for cell death, expression of Bcl-family proteins, and white-matter sparing. Post-SCI administration of the 0.5- or 5.0-mg pellet improved hindlimb locomotion, reduced urinary bladder size, increased neuronal survival, reduced apoptosis, improved the Bax/Bcl-xL protein ratio, and increased white-matter sparing. In the absence of endogenous testicular-derived androgens, SCI induced greater apoptosis, yet 17beta-estradiol administration reduced apoptosis to the same extent in gonadectomized and gonad-intact male rats. These data suggest that delayed post-SCI administration of a clinically relevant dose of 17beta-estradiol is protective in male rats, and endogenous androgens do not alter estrogen-mediated protection. These data suggest that 17beta-estradiol is an effective therapeutic intervention for reducing secondary damage after SCI in males, which could be readily translated to clinical trials.

  13. Cell mediated immune response after challenge in Omp25 liposome immunized mice contributes to protection against virulent Brucella abortus 544.

    PubMed

    Goel, Divya; Rajendran, Vinoth; Ghosh, Prahlad C; Bhatnagar, Rakesh

    2013-02-06

    Brucellosis is a disease affecting various domestic and wild life species, and is caused by a bacterium Brucella. Keeping in view the serious economic and medical consequences of brucellosis, efforts have been made to prevent the infection through the use of vaccines. Cell-mediated immune responses [CMI] involving interferon gamma and cytotoxic CD4(+) and CD8(+) T cells are required for removal of intracellular Brucella. Omp25 has been reported to be involved in virulence of Brucella melitensis, Brucella abortus and Brucella ovis. In our previous study, we have shown the protective efficacy of recombinant Omp25, when administered intradermally. In this study, the recombinant Omp25 was formulated in PC-PE liposomes and PLGA microparticles, to enhance the protective immunity generated by it. Significant protection was seen with prime and booster liposome immunization in Balb/c mice against virulent B. abortus 544 as it was comparable to B. abortus S-19 vaccine strain. However, microparticle prime and booster immunization failed to give better protection when compared to B. abortus S-19 vaccine strain. This difference can be attributed to the stimulation of cell mediated immune response in PC-PE liposome immunized mice even after challenge which converted to cytotoxicity seen in CD4(+) and CD8(+) enriched lymphocytes. However, in PLGA microparticle immunized mice, cell mediated immunity was not generated after challenge as observed by decreased cytotoxicity of CD4(+) and CD8(+) enriched lymphocytes. Our study emphasizes on the importance of liposome encapsulating Omp25 immunization in conferring protection against B. abortus 544 challenge in Balb/c mice with a single dose immunization regimen.

  14. Stretchy Proteins on Stretchy Substrates: The Important Elements of Integrin-Mediated Rigidity Sensing

    PubMed Central

    Moore, Simon W.; Roca-Cusachs, Pere; Sheetz, Michael P.

    2013-01-01

    Matrix and tissue rigidity guides many cellular processes, including the differentiation of stem cells and the migration of cells in health and disease. Cells actively and transiently test rigidity using mechanisms limited by inherent physical parameters that include the strength of extracellular attachments, the pulling capacity on these attachments, and the sensitivity of the mechanotransduction system. Here we focus on rigidity sensing mediated through the integrin family of extracellular matrix receptors and linked proteins, and discuss the evidence supporting these proteins as mechanosensors. PMID:20708583

  15. Brazed graphite/refractory metal composites for first-wall protection elements

    NASA Astrophysics Data System (ADS)

    Šmid, I.; Croessmann, C. D.; Salmonson, J. C.; Whitley, J. B.; Kny, E.; Reheis, N.; Kneringer, G.; Nickel, H.

    1991-03-01

    The peak surface heat flux deposition on divertor elements of near term fusion devices is expected to exceed 10 MW/m 2. The needed reliability of brazed plasma interactive components, particularly under abnormal operating conditions with peak surface temperatures well beyond 1000°C, makes refractory metallic substrates and brazes with a high melting point very attractive. TZM, a high temperature alloy of molybdenum, and isotropic graphite, materials very closely matched in their thermal expansion, were brazed with four high-temperature brazes. The brazes used were Zr, 90Ni/10Ti, 90Cu/10Ti and 70Ag/27Cu/3Ti (nominal composition prior to brazing, wt%). The resulting composite tiles of 50 × 50 mm2 with a TZM thickness of 5 mm and a graphite thickness of 10 mm have been tested in high heat flux simulation for their thermal fatigue properties. Up to 600 loading cycles were carried out with an average heat flux of 10 MW/m 2 for 0.5 s pulses. The maximum surface temperature was 1100°C. In support of the experiment, the thermal response and temperature gradients of the samples were investigated using a finite element model.

  16. Replacement of Ablators with Phase-Change Material for Thermal Protection of STS Elements

    NASA Technical Reports Server (NTRS)

    Kaul, Raj K.; Stuckey, Irvin; Munafo, Paul M. (Technical Monitor)

    2002-01-01

    As part of the research and development program to develop new Thermal Protection System (TPS) materials for aerospace applications at NASA's Marshall Space Flight Center (MSFC), an experimental study was conducted on a new concept for a non-ablative TPS material. Potential loss of TPS material and ablation by-products from the External Tank (ET) or Solid Rocket Booster (SRB) during Shuttle flight with the related Orbiter tile damage necessitates development of a non-ablative thermal protection system. The new Thermal Management Coating (TMC) consists of phase-change material encapsulated in micro spheres and a two-part resin system to adhere the coating to the structure material. The TMC uses a phase-change material to dissipate the heat produced during supersonic flight rather than an ablative material. This new material absorbs energy as it goes through a phase change during the heating portion of the flight profile and then the energy is slowly released as the phase-change material cools and returns to its solid state inside the micro spheres. The coating was subjected to different test conditions simulating design flight environments at the NASA/MSFC Improved Hot Gas Facility (IHGF) to study its performance.

  17. Radioactive resistance of elements for over-voltage protection of low-voltage systems

    NASA Astrophysics Data System (ADS)

    Osmokrovic, P.; Stojanovic, M.; Loncar, B.; Kartalovic, N.; Krivokapic, I.

    1998-04-01

    Aim of this work is to examine the over-voltage protection under the ionizing radiation influence. The use of modern electronic devices (nuclear, military and space technology) in the conditions of ionizing radiation brings up the question of radioactive resistance of electronic components and over-voltage protection components. The question of reliability of these components under the influence of ionizing radiation is also a relevant one. The entire effects of radiation, which cause the irreversible changes of the material characteristics, are defined as the dosage or integral effects. The resistance of the over-voltage material (the Transient Suppresser Diodes (TSD), Metaloxide Varistors, Gas Filled Surge Arresters (GFSA) and Polycarbon Capacitors) subjected to influence of n +γ radiation caused by californium source was examined in order to determine the radiation effects. It was determined that TSD are highly sensitive to the radiation. The radiation effects on Metaloxide Varistors are similar to the effects on the TSD. GFSA showed the temporary characteristics improvement. It was determined that the Polycarbon Capacitor capacity decreases under the influence of radiation. The obtained results are explained theoretically.

  18. Dietary intakes of seven elements of importance in radiological protection by asian population: comparison with ICRP data.

    PubMed

    Iyengar, G V; Kawamura, H; Dang, H S; Parr, R M; Wang, J; Akhter, Perveen; Cho, S Y; Natera, E; Miah, F K; Dojosubroto, J; Nguyen, M S

    2004-06-01

    Within the framework of a Coordinated Research Project (CRP) organized by the International Atomic Energy Agency, Vienna, the daily dietary intakes of seven elements by adult populations living in nine Asian countries were estimated. The countries that participated in the study were Bangladesh, China, India, Indonesia, Japan, Pakistan, Philippines, South Korea (Republic of Korea, ROK), and Vietnam and together they represented more than half of the world population. The seven elements studied were calcium, cesium, iodine, potassium, strontium, thorium, and uranium. These elements have chemical and biological similarity to some of the radionuclides abundantly encountered during nuclear power production and therefore data on these elements could provide important information on their biokinetic behavior. Analyses of diet samples for these seven elements were carried out using highly sensitive and reliable analytical techniques. One thousand one hundred and sixty analytical determinations were made on two hundred and twenty samples of typical diets consumed in these countries to estimate the daily intakes of these elements by the adult Asian population. The median daily dietary intakes for the adult Asian population were found to be 0.45 g calcium, 7 microg cesium, 90 microg iodine, 1.75 g potassium, 1.65 mg strontium, 1 microg thorium, and 1 microg uranium. When compared with the intakes proposed for ICRP Reference Man by International Commission for Radiological Protection, these intakes were lower by factors of 0.41 for calcium, 0.7 for cesium, 0.45 for iodine, 0.53 for potassium, 0.87 for strontium, 0.33 for thorium, and 0.52 for uranium. The lower daily intakes of calcium, cesium, and iodine by Asian population could be due to significantly lower consumption of milk and milk products, which are rich in these elements. The significantly lower intake of calcium in most of the Asian countries may lead to higher uptake of fission nuclide 90Sr and could result in

  19. Linear amplification mediated PCR--localization of genetic elements and characterization of unknown flanking DNA.

    PubMed

    Gabriel, Richard; Kutschera, Ina; Bartholomae, Cynthia C; von Kalle, Christof; Schmidt, Manfred

    2014-06-25

    Linear-amplification mediated PCR (LAM-PCR) has been developed to study hematopoiesis in gene corrected cells of patients treated by gene therapy with integrating vector systems. Due to the stable integration of retroviral vectors, integration sites can be used to study the clonal fate of individual cells and their progeny. LAM- PCR for the first time provided evidence that leukemia in gene therapy treated patients originated from provirus induced overexpression of a neighboring proto-oncogene. The high sensitivity and specificity of LAM-PCR compared to existing methods like inverse PCR and ligation mediated (LM)-PCR is achieved by an initial preamplification step (linear PCR of 100 cycles) using biotinylated vector specific primers which allow subsequent reaction steps to be carried out on solid phase (magnetic beads). LAM-PCR is currently the most sensitive method available to identify unknown DNA which is located in the proximity of known DNA. Recently, a variant of LAM-PCR has been developed that circumvents restriction digest thus abrogating retrieval bias of integration sites and enables a comprehensive analysis of provirus locations in host genomes. The following protocol explains step-by-step the amplification of both 3'- and 5'- sequences adjacent to the integrated lentiviral vector.

  20. Rostral elements of sympatho-motor circuitry: a virally mediated transsynaptic tracing study.

    PubMed

    Kerman, Ilan A; Akil, Huda; Watson, Stanley J

    2006-03-29

    Numerous physiological and emotionally motivated behaviors, including locomotion, exercise, escape, and attack behaviors as well as passive coping responses, require concomitant activation of motor and sympathetic efferents. Such functional heterogeneity suggests the existence of dual function neurons that can simultaneously coordinate motor and sympathetic output. Because previous physiological investigations have implicated a number of mesencephalic and telencephalic regions in mediating these behaviors, we hypothesized the presence of dual function sympatho-motor neurons in these neural structures. To test this hypothesis, we used recombinant strains of the pseudorabies virus (PRV) for transsynaptic tract-tracing. PRV-152, a strain that expresses enhanced green fluorescent protein, was injected into sympathectomized gastrocnemius muscle, whereas PRV-BaBlu, which expresses beta-galactosidase, was injected into the adrenal gland in the same animals. Although coinfected neurons were detected in a number of mesencephalic and telencephalic regions, >50% of such neurons were located within specific subdivisions of two general areas: the hypothalamus and periaqueductal gray. These subdivisions included the ventrolateral periaqueductal gray, dorsomedial hypothalamus, dorsolateral lateral hypothalamus, and ventral portion of the medial parvocellular subdivision of the paraventricular nucleus of the hypothalamus (PVN). A subset of the sympatho-motor neurons within the PVN also contained either arginine vasopressin or oxytocin. This sympatho-motor circuitry likely plays an important role in mediating different aspects of stress responses and emotionally motivated behaviors.

  1. Predictive Effects of Good Self-Control and Poor Regulation on Alcohol-Related Outcomes: Do Protective Behavioral Strategies Mediate?

    PubMed Central

    Pearson, Matthew R.; Kite, Benjamin A.; Henson, James M.

    2016-01-01

    In the present study, we examined whether use of protective behavioral strategies mediated the relationship between self-control constructs and alcohol-related outcomes. According to the two-mode model of self-control, good self-control (planfulness; measured with Future Time Perspective, Problem Solving, and Self-Reinforcement) and poor regulation (impulsivity; measured with Present Time Perspective, Poor Delay of Gratification, Distractibility) are theorized to be relatively independent constructs rather than opposite ends of a single continuum. The analytic sample consisted of 278 college student drinkers (68% women) who responded to a battery of surveys at a single time point. Using a structural equation model based on the two-mode model of self-control, we found that good self-control predicted increased use of three types of protective behavioral strategies (Manner of Drinking, Limiting/Stopping Drinking, and Serious Harm Reduction). Poor regulation was unrelated to use of protective behavioral strategies, but had direct effects on alcohol use and alcohol problems. Further, protective behavioral strategies mediated the relationship between good self-control and alcohol use. The clinical implications of these findings are discussed. PMID:22663345

  2. Breast cancer prevention: lessons to be learned from mechanisms of early pregnancy-mediated breast cancer protection.

    PubMed

    Meier-Abt, Fabienne; Bentires-Alj, Mohamed; Rochlitz, Christoph

    2015-03-01

    Pregnancy at early, but not late age, has a strong and life-long protective effect against breast cancer. The expected overall increase in breast cancer incidence demands the development of a pharmaceutical mimicry of early-age pregnancy-mediated protection. Recently, converging results from rodent models and women on molecular and cellular mechanisms underlying the protective effect of early-age pregnancy have opened the door for translational studies on pharmacologic prevention against breast cancer. In particular, alterations in Wnt and TGFβ signaling in mammary stem/progenitor cells reveal new potential targets for preventive interventions, and thus might help to significantly reduce the incidence of breast cancer in the future. ©2015 American Association for Cancer Research.

  3. Optimism and the brain: trait optimism mediates the protective role of the orbitofrontal cortex gray matter volume against anxiety

    PubMed Central

    Hu, Yifan; Iordan, Alexandru D.; Moore, Matthew; Dolcos, Florin

    2016-01-01

    Converging evidence identifies trait optimism and the orbitofrontal cortex (OFC) as personality and brain factors influencing anxiety, but the nature of their relationships remains unclear. Here, the mechanisms underlying the protective role of trait optimism and of increased OFC volume against symptoms of anxiety were investigated in 61 healthy subjects, who completed measures of trait optimism and anxiety, and underwent structural scanning using magnetic resonance imaging. First, the OFC gray matter volume (GMV) was associated with increased optimism, which in turn was associated with reduced anxiety. Second, trait optimism mediated the relation between the left OFC volume and anxiety, thus demonstrating that increased GMV in this brain region protects against symptoms of anxiety through increased optimism. These results provide novel evidence about the brain–personality mechanisms protecting against anxiety symptoms in healthy functioning, and identify potential targets for preventive and therapeutic interventions aimed at reducing susceptibility and increasing resilience against emotional disturbances. PMID:26371336

  4. Endothelin-2-Mediated Protection of Mutant Photoreceptors in Inherited Photoreceptor Degeneration

    PubMed Central

    Bramall, Alexa N.; Szego, Michael J.; Pacione, Laura R.; Chang, Inik; Diez, Eduardo; D'Orleans-Juste, Pedro; Stewart, Duncan J.; Hauswirth, William W.; Yanagisawa, Masashi; McInnes, Roderick R.

    2013-01-01

    Expression of the Endothelin-2 (Edn2) mRNA is greatly increased in the photoreceptors (PRs) of mouse models of inherited PR degeneration (IPD). To examine the role of Edn2 in mutant PR survival, we generated Edn2−/− mice carrying homozygous Pde6brd1 alleles or the Tg(RHO P347S) transgene. In the Edn2−/− background, PR survival increased 110% in Pde6brd1/rd1 mice at post-natal (PN) day 15, and 60% in Tg(RHO P347S) mice at PN40. In contrast, PR survival was not increased in retinal explants of Pde6brd1/rd1; Edn2−/− mice. This finding, together with systemic abnormalities in Edn2−/− mice, suggested that the increased survival of mutant PRs in the Edn2−/− background resulted at least partly from the systemic EDN2 loss of function. To examine directly the role of EDN2 in mutant PRs, we used a scAAV5-Edn2 cDNA vector to restore Edn2 expression in Pde6brd1/rd1; Edn2−/− PRs and observed an 18% increase in PR survival at PN14. Importantly, PR survival was also increased after injection of scAAV5-Edn2 into Pde6brd1/rd1 retinas, by 31% at PN15. Together, these findings suggest that increased Edn2 expression is protective to mutant PRs. To begin to elucidate Edn2-mediated mechanisms that contribute to PR survival, we used microarray analysis and identified a cohort of 20 genes with >4-fold increased expression in Tg(RHO P347S) retinas, including Fgf2. Notably, increased expression of the FGF2 protein in Tg(RHO P347S) PRs was ablated in Tg(RHO P347S); Edn2−/− retinas. Our findings indicate that the increased expression of PR Edn2 increases PR survival, and suggest that the Edn2-dependent increase in PR expression of FGF2 may contribute to the augmented survival. PMID:23469133

  5. Protective effect of pomegranate-derived products on UVB-mediated damage in human reconstituted skin.

    PubMed

    Afaq, Farrukh; Zaid, Mohammad Abu; Khan, Naghma; Dreher, Mark; Mukhtar, Hasan

    2009-06-01

    Solar ultraviolet (UV) radiation, particularly its UVB (290-320 nm) component, is the primary cause of many adverse biological effects including photoageing and skin cancer. UVB radiation causes DNA damage, protein oxidation and induces matrix metalloproteinases (MMPs). Photochemoprevention via the use of botanical antioxidants in affording protection to human skin against UVB damage is receiving increasing attention. Pomegranate, from the tree Punica granatum, contains anthocyanins and hydrolysable tannins and possesses strong antioxidant and anti-tumor-promoting properties. In this study, we determined the effect of pomegranate-derived products--POMx juice, POMx extract and pomegranate oil (POMo)--against UVB-mediated damage using reconstituted human skin (EpiDerm(TM) FT-200). EpiDerm was treated with POMx juice (1-2 microl/0.1 ml/well), POMx extract (5-10 microg/0.1 ml/well) and POMo (1-2 microl/0.1 ml/well) for 1 h prior to UVB (60 mJ/cm(2)) irradiation and was harvested 12 h post-UVB to assess protein oxidation, markers of DNA damage and photoageing by Western blot analysis and immunohistochemistry. Pretreatment of Epiderm with pomegranate-derived products resulted in inhibition of UVB-induced (i) cyclobutane pyrimidine dimers (CPD), (ii) 8-dihydro-2'-deoxyguanosine (8-OHdG), (iii) protein oxidation and (iv) proliferating cell nuclear antigen (PCNA) protein expression. We also found that pretreatment of Epiderm with pomegranate-derived products resulted in inhibition of UVB-induced (i) collagenase (MMP-1), (ii) gelatinase (MMP-2, MMP-9), (iii) stromelysin (MMP-3), (iv) marilysin (MMP-7), (v) elastase (MMP-12) and (vi) tropoelastin. Gelatin zymography revealed that pomegranate-derived products inhibited UVB-induced MMP-2 and MMP-9 activities. Pomegranate-derived products also caused a decrease in UVB-induced protein expression of c-Fos and phosphorylation of c-Jun. Collectively, these results suggest that all three pomegranate-derived products may be useful

  6. T cells play an essential role in anti-F1 mediated rapid protection against bubonic plague.

    PubMed

    Levy, Yinon; Flashner, Yehuda; Tidhar, Avital; Zauberman, Ayelet; Aftalion, Moshe; Lazar, Shirley; Gur, David; Shafferman, Avigdor; Mamroud, Emanuelle

    2011-09-16

    Plague, which is initiated by Yersinia pestis infection, is a fatal disease that progresses rapidly and leads to high mortality rates if not treated. Antibiotics are an effective plague therapy, but antibiotic-resistant Y. pestis strains have been reported and therefore alternative countermeasures are needed. In the present study, we assessed the potential of an F1 plus LcrV-based vaccine to provide protection shortly pre- or post-exposure to a lethal Y. pestis infection. Mice vaccinated up to one day before or even several hours after subcutaneous challenge were effectively protected. Mice immunized one or three days pre-challenge were protected even though their anti-F1 and anti-LcrV titers were below detection levels at the day of challenge. Moreover, using B-cell deficient μMT mice, we found that rapidly induced protective immunity requires the integrity of the humoral immune system. Analysis of the individual contributions of vaccine components to protection revealed that rF1 is responsible for the observed rapid antibody-mediated immunity. Applying anti-F1 passive therapy in the mouse model of bubonic plague demonstrated that anti-F1 F(ab')(2) can delay mortality, but it cannot provide long-lasting protection, as do intact anti-F1 molecules. Fc-dependent immune components, such as the complement system and (to a lesser extent) neutrophils, were found to contribute to mouse survival. Interestingly, T cells but not B cells were found to be essential for the recovery of infected animals following passive anti-F1 mediated therapy. These data extend our understanding of the immune mechanisms required for the development of a rapid and effective post-exposure therapy against plague. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Zinc as an essential trace element in the acceleration of matrix vesicles-mediated mineral deposition.

    PubMed

    Kawakubo, Atsushi; Matsunaga, Tsunenori; Ishizaki, Hidetaka; Yamada, Shizuka; Hayashi, Yoshihiko

    2011-12-01

    Zinc (Zn) has a potent stimulatory effect on osteoblastic bone formation and an inhibitory effect on osteoclastic bone resorption. The effect of Zn on the function of matrix vesicles (MVs) remains controversial. The purpose of this study was to investigate the effect of Zn on alkaline phosphatase (ALP) activity of osteoblasts and in the initial biological MVs-mediated mineral deposition. Osteoblasts were treated with varying concentrations of Zn dissolved in culture medium. After three, five, and seven days of culture, ALP activity was assayed. For the detection of a low level of calcium concentration in MVs, X-ray fluorescence (XRF) analyses were applied. The effect of Zn for the transformation of calcium phosphate was analyzed using a scanning electron microscope fitted with an energy dispersive X-ray microanalysis (EDX) system. The ALP activity of osteoblasts in culture medium supplemented with 1 × 10(-5) M of Zn was significantly increased at both five and seven days. XRF data demonstrated higher levels of calcium concentration over time in the Zn-supplemented group. EDX data showed that mineral deposits beginning on day 3 were transformed from whitlockite to calcium phosphate near hydroxyapatite, and that Zn accelerated this transformation. The proper concentration of Zn increased the ALP activity of osteoblasts after five and seven days of incubation. The present XRF and EDX data suggest that the increase of mineral deposition with Zn exposure for one to five days might be mediated by the activation of ALP and calcium-binding proteins. Copyright © 2011 Wiley Periodicals, Inc.

  8. Erythropoietin-mediated protection of insect brain neurons involves JAK and STAT but not PI3K transduction pathways.

    PubMed

    Miljus, N; Heibeck, S; Jarrar, M; Micke, M; Ostrowski, D; Ehrenreich, H; Heinrich, R

    2014-01-31

    The cytokine erythropoietin (Epo) initiates adaptive cellular responses to both moderate environmental challenges and tissue damaging insults in various non-hematopoietic mammalian tissues including the nervous system. Neuroprotective and neuroregenerative functions of Epo in mammals are mediated through receptor-associated Janus kinase 2 and intracellular signaling cascades that modify the transcription of Epo-regulated genes. Signal transducers and activators of transcription (STAT) and phosphoinositol-3-kinase (PI3K) represent key components of two important Epo-induced transduction pathways. Our previous study on insects revealed neuroprotective and regenerative functions of recombinant human Epo (rhEpo) similar to those in mammalian nervous tissues. Here we demonstrate that rhEpo effectively rescues primary cultured locust brain neurons from apoptotic cell death induced by hypoxia or the chemical compound H-7. The Janus kinase inhibitor AG-490 and the STAT inhibitor sc-355797 abolished protective effects of rhEpo on locust brain neurons. In contrast, inhibition of PI3K with LY294002 had no effect on rhEpo-mediated neuroprotection. The results indicate that rhEpo mediates the protection of locust brain neurons through interference with apoptotic pathways by the activation of a Janus kinase-associated receptor and STAT transcription factor(s). The involvement of similar transduction pathways in mammals and insects for the mediation of neuroprotection and support of neural regeneration by Epo indicates that an Epo/Epo receptor-like signaling system with high structural and functional similarity exists in both groups of animals. Epo-like signaling involved in tissue protection appears to be an ancient beneficial function shared by vertebrates and invertebrates.

  9. Fe(III) oxides protect fermenter-methanogen syntrophy against interruption by elemental sulfur via stiffening of Fe(II) sulfides produced by sulfur respiration.

    PubMed

    Igarashi, Kensuke; Kuwabara, Tomohiko

    2014-03-01

    Thermosipho globiformans (rod-shaped thermophilic fermenter) and Methanocaldococcus jannaschii (coccal hyperthermophilic hydrogenotrophic methanogen) established H2-mediated syntrophy at 68 °C, forming exopolysaccharide-based aggregates. Electron microscopy showed that the syntrophic partners connected to each other directly or via intercellular bridges made from flagella, which facilitated transfer of H2. Elemental sulfur (S(0)) interrupted syntrophy; polysulfides abiotically formed from S(0) intercepted electrons that were otherwise transferred to H(+) to produce H2, resulting in the generation of sulfide (sulfur respiration). However, Fe(III) oxides significantly reduced the interruption by S(0), accompanied by stiffening of Fe(II) sulfides produced by the reduction of Fe(III) oxides with the sulfur respiration-generated sulfide. Sea sand replacing Fe(III) oxides failed to generate stiffening or protect the syntrophy. Several experimental results indicated that the stiffening of Fe(II) sulfides shielded the liquid from S(0), resulting in methane production in the liquid. Field-emission scanning electron microscopy showed that the stiffened Fe(II) sulfides formed a network of spiny structures in which the microorganisms were buried. The individual fermenter rods likely produced Fe(II) sulfides on their surface and became local centers of a core of spiny structures, and the connection of these cores formed the network, which was macroscopically recognized as stiffening.

  10. Protection from radiation-induced enteropathy by elemental diet feeding: The role of free radicals

    SciTech Connect

    McArdle, A.H.; Duong, M.N. )

    1991-03-15

    Free radicals have been implicated in intestinal reperfusion injury following ischemia and in epithelial cell damage resulting from ionizing radiation. Elemental diets (ED) have been shown to afford significant prophylaxis to the intestine from these injuries. The purpose of the present study was to investigate whether ED alters the activity of the defense mechanisms necessary for free radical removal. Six female dogs, fed on normal dog chow, had a 30 cm resection of terminal ileum to form Thiry-Vella loops. The main intestine was biopsied and anastomosed. Two weeks later, biopsies were taken from the lips of the loops. Following this, the loops were fed daily with ED another 2 weeks and biopsied again. The dogs were then placed on ED for 3 days before and during 4 days of pelvic irradiation, and the loops also were fed ED daily; after which the animals were again anesthetized, and the loops and main intestine were biopsied. All biopsies were processed for histology, and assayed for xanthine oxidase (XO), superoxide dismutase (SOD), glutathione peroxidase (GSP) and catalase (CAT). The XO and SOD pathway of free oxygen radical generation and scavenging are not affected by radiation. However, ED lowers both XO and SOD activity and may result in a reduced production of peroxides. The significantly increased activity of GSP and CAT when ED is fed improves the scavenging capacity of the free hydroxyl radicals generated by the radiation, and is an important adjunct to an understanding of ED prophylaxis.

  11. Protection against acetaminophen-induced liver injury by allopurinol is dependent on aldehyde oxidase-mediated liver preconditioning

    SciTech Connect

    Williams, C. David; McGill, Mitchell R.; Lebofsky, Margitta; Bajt, Mary Lynn; Jaeschke, Hartmut

    2014-02-01

    Acetaminophen (APAP) overdose causes severe and occasionally fatal liver injury. Numerous drugs that attenuate APAP toxicity have been described. However these compounds frequently protect by cytochrome P450 inhibition, thereby preventing the initiating step of toxicity. We have previously shown that pretreatment with allopurinol can effectively protect against APAP toxicity, but the mechanism remains unclear. In the current study, C3HeB/FeJ mice were administered allopurinol 18 h or 1 h prior to an APAP overdose. Administration of allopurinol 18 h prior to APAP overdose resulted in an 88% reduction in liver injury (serum ALT) 6 h after APAP; however, 1 h pretreatment offered no protection. APAP-cysteine adducts and glutathione depletion kinetics were similar with or without allopurinol pretreatment. The phosphorylation and mitochondrial translocation of c-jun-N-terminal-kinase (JNK) have been implicated in the progression of APAP toxicity. In our study we showed equivalent early JNK activation (2 h) however late JNK activation (6 h) was attenuated in allopurinol treated mice, which suggests that later JNK activation is more critical for the toxicity. Additional mice were administered oxypurinol (primary metabolite of allopurinol) 18 h or 1 h pre-APAP, but neither treatment protected. This finding implicated an aldehyde oxidase (AO)-mediated metabolism of allopurinol, so mice were treated with hydralazine to inhibit AO prior to allopurinol/APAP administration, which eliminated the protective effects of allopurinol. We evaluated potential targets of AO-mediated preconditioning and found increased hepatic metallothionein 18 h post-allopurinol. These data show metabolism of allopurinol occurring independent of P450 isoenzymes preconditions the liver and renders the animal less susceptible to an APAP overdose. - Highlights: • 18 h allopurinol pretreatment protects against acetaminophen-induced liver injury. • 1 h allopurinol pretreatment does not protect from APAP

  12. Utilization of cholera toxin B as a mucosal adjuvant elicits antibody-mediated protection against S. pneumoniae infection in mice

    PubMed Central

    Wiedinger, Kari; Pinho, Daniel; Bitsaktsis, Constantine

    2017-01-01

    Backgound: The introduction of the pneumococcal conjugate and polysaccharide vaccines have been valuable tools for combating invasive pneumococcal infection in children and healthy adults. Despite the available vaccination strategies, pneumococcal pneumonia and associated diseases continue to cause substantial morbidity and mortality, particularly in individuals with chronic disease and ageing populations. Next-generation pneumococcal vaccines will need to be highly immunogenic across patient populations providing both mucosal and systemic protective immunity. Mucosal immunization is an effective strategy for stimulating the immune response at the site of pathogen entry while increasing systemic immunity. In this study we utilized intranasal immunization with pneumococcal surface protein A (PspA), in combination with the mucosal adjuvant cholera toxin B (CTB), to characterize the immune components providing protection against S. pneumoniae challenge. Methods: Mice were immunized intranasally with CTB and PspA individually, and in combination, followed by lethal bacterial challenge with S. pneumoniae, strain A66.1. Animals were monitored for survival and tested for lung bacterial burden, cytokine production as well as S. pneumoniae-specific antibody titer in mouse sera. The primary immunological contributor to the observed protection was confirmed by cytokine neutralization and serum passive transfer. Results: The combination of CTB and PspA provided complete protection against bacterial challenge, which coincided with a significant decrease in lung bacterial burden. Increases in the T-helper (Th) 1 cytokines, interferon (IFN)-γ and interleukin (IL)-2 were observed in the lung 24 h post-challenge while decreases in proinflammatory mediators IL-6 and tumor necrosis factor (TNF)-α were also recorded at the same time point. The adjuvanted PspA immunization induced significant titers of S. pneumoniae-specific antibody in the serum of mice prior to infection. Serum

  13. Finite-element analysis of the optical-texture-mediated photoresponse in a nematic strip

    NASA Astrophysics Data System (ADS)

    Chung, Hayoung; Yun, Jung-Hoon; Choi, Joonmyung; Cho, Maenghyo

    2016-10-01

    In a nematic solid, wherein liquid crystal molecules are incorporated into polymeric chains, the chromophore phase is projected onto the polymer conformation, changing the stress-free configuration metric. Stimulated actuation cannot be separated from the structure itself, since the mesoscopic polymer properties dictate the degree and type of shape change. In this research, we focused on self-deforming device programming, inspired by recent optical techniques, to pattern nontrivial alignment textures and induce exotic strain fields on specimens. A finite-element framework incorporating a light-thermo-order coupled constitutive relation and geometric nonlinearities was utilized to compute mechanical deformations for given external stimuli. The distortion of planar strips into various exotic 3D shapes was simulated, and disclination-defect-like liquid crystal texture topographies with different defect strengths produced various many-poled shapes upon irradiation, as observed experimentally. The effects of the boundary conditions and geometric nonlinearities were also examined, exemplifying the need for a comprehensive finite-element-based framework. The same method was applied to textures naturally emerging due to static distortion, and the effects of the prescribed inhomogeneities on the overall deformations, which is the basis of inverse design, were observed. Furthermore, we analyzed the local Poisson-effect-induced instability resulting from inscribing a hedgehog disclination texture onto a solid; the onset of buckling-like deformations was observed energetically, and the relations between this onset and other physical properties were elucidated to enable microstate design while maintaining structural stability. These results will facilitate the development and comprehension of the mechanisms of remotely light-controlled self-assembly and propulsion systems that may soon be realized.

  14. Involvement of multiple elements in FXR-mediated transcriptional activation of FGF19.

    PubMed

    Miyata, Masaaki; Hata, Tatsuya; Yamakawa, Hiroki; Kagawa, Tatehiro; Yoshinari, Kouichi; Yamazoe, Yasushi

    2012-10-01

    The intestinal endocrine hormone human fibroblast growth factor 19 (FGF19) is involved in the regulation of not only hepatic bile acid metabolism but also carbohydrate and lipid metabolism. In the present study, bile acid/farnesoid X receptor (FXR) responsiveness in the FGF19 promoter region was investigated by a reporter assay using the human colon carcinoma cell line LS174T. The assay revealed the presence of bile acid/FXR-responsive elements in the 5'-flanking region up to 8.8 kb of FGF19. Deletion analysis indicated that regions from -1866 to -1833, from -1427 to -1353, and from -75 to +262 were involved in FXR responsiveness. Four, four, and two consecutive half-sites of nuclear receptors were observed in the three regions, respectively. An electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay revealed FXR/retinoid X receptor α (RXRα) heterodimer binding in these three regions. EMSA and reporter assays using mutated constructs indicated that the nuclear receptor IR1, ER2, and DR8 motifs in the 5'-flanking region were involved in FXR responsiveness of FGF19. Lithocholic acid (LCA) (10 μM), chenodeoxycholic acid (CDCA) (10 μM), or GW4064 (0.1 μM) treatment increased reporter activity in a construct including the three motifs under FXR-expressing conditions whereas LCA and not CDCA or GW4064 treatment increased the reporter activity under pregnane X receptor (PXR)-expressing conditions. These results suggest that FGF19 is transcriptionally activated through multiple FXR-responsive elements in the promoter region.

  15. Intronic hormone response elements mediate regulation of FKBP5 by progestins and glucocorticoids.

    PubMed

    Hubler, Tina R; Scammell, Jonathan G

    2004-01-01

    Expression of FKBP51, a large molecular weight immunophilin, is strongly enhanced by glucocorticoids, progestins, and androgens. However, the activity of a 3.4-kb fragment of the FKBP51 gene (FKBP5) promoter was only weakly increased by progestin and we show here that it is unresponsive to glucocorticoids and androgens. The entire FKBP5 was scanned for consensus hormone response elements (HREs) using MatInspector. We found that 2 regions of intron E, which are conserved in rat and mouse FKBP5, contain HRE-like sequences with high match scores. Deoxyribonucleic acid fragments (approximately 1 kb in length) containing these regions were amplified and tested in reporter gene assays for steroid responsiveness. One region of intron E of FKBP5 (pIE2) conferred both glucocorticoid and progestin responsiveness to 2 heterologous reporter genes, whereas the other, less-conserved region of intron E (pIE1) was responsive only to progestins. The inclusion of pIE1 upstream of pIE2 (pIE1IE2) enhanced progestin but not glucocorticoid responsiveness. None of the constructs containing intronic sequences was responsive to androgens. Mutation of the putative HREs within pIE1 and pIE2 eliminated hormone responsiveness. Electrophoretic mobility shift assays demonstrated that progesterone receptors (PR) bound to the HRE in pIE1, whereas both PR and glucocorticoid receptors interacted with the HRE in pIE2. These data suggest that distal intronic elements significantly contribute to transcriptional regulation of FKBP5 by glucocorticoids and progestins.

  16. Finite-element analysis of the optical-texture-mediated photoresponse in a nematic strip

    NASA Astrophysics Data System (ADS)

    Chung, Hayoung; Yun, Jung-Hoon; Choi, Joonmyung; Cho, Maenghyo

    2017-01-01

    In a nematic solid, wherein liquid crystal molecules are incorporated into polymeric chains, the chromophore phase is projected onto the polymer conformation, changing the stress-free configuration metric. Stimulated actuation cannot be separated from the structure itself, since the mesoscopic polymer properties dictate the degree and type of shape change. In this research, we focused on self-deforming device programming, inspired by recent optical techniques, to pattern nontrivial alignment textures and induce exotic strain fields on specimens. A finite-element framework incorporating a light-thermo-order coupled constitutive relation and geometric nonlinearities was utilized to compute mechanical deformations for given external stimuli. The distortion of planar strips into various exotic 3D shapes was simulated, and disclination-defect-like liquid crystal texture topographies with different defect strengths produced various many-poled shapes upon irradiation, as observed experimentally. The effects of the boundary conditions and geometric nonlinearities were also examined, exemplifying the need for a comprehensive finite-element-based framework. The same method was applied to textures naturally emerging due to static distortion, and the effects of the prescribed inhomogeneities on the overall deformations, which is the basis of inverse design, were observed. Furthermore, we analyzed the local Poisson-effect-induced instability resulting from inscribing a hedgehog disclination texture onto a solid; the onset of buckling-like deformations was observed energetically, and the relations between this onset and other physical properties were elucidated to enable microstate design while maintaining structural stability. These results will facilitate the development and comprehension of the mechanisms of remotely light-controlled self-assembly and propulsion systems that may soon be realized.

  17. Replication termination at eukaryotic chromosomes is mediated by Top2 and occurs at genomic loci containing pausing elements.

    PubMed

    Fachinetti, Daniele; Bermejo, Rodrigo; Cocito, Andrea; Minardi, Simone; Katou, Yuki; Kanoh, Yutaka; Shirahige, Katsuhiko; Azvolinsky, Anna; Zakian, Virginia A; Foiani, Marco

    2010-08-27

    Chromosome replication initiates at multiple replicons and terminates when forks converge. In E. coli, the Tus-TER complex mediates polar fork converging at the terminator region, and aberrant termination events challenge chromosome integrity and segregation. Since in eukaryotes, termination is less characterized, we used budding yeast to identify the factors assisting fork fusion at replicating chromosomes. Using genomic and mechanistic studies, we have identified and characterized 71 chromosomal termination regions (TERs). TERs contain fork pausing elements that influence fork progression and merging. The Rrm3 DNA helicase assists fork progression across TERs, counteracting the accumulation of X-shaped structures. The Top2 DNA topoisomerase associates at TERs in S phase, and G2/M facilitates fork fusion and prevents DNA breaks and genome rearrangements at TERs. We propose that in eukaryotes, replication fork barriers, Rrm3, and Top2 coordinate replication fork progression and fusion at TERs, thus counteracting abnormal genomic transitions.

  18. Hypoxia inducible factor-1 mediates the expression of the immune checkpoint HLA-G in glioma cells through hypoxia response element located in exon 2

    PubMed Central

    Yaghi, Layale; Poras, Isabelle; Simoes, Renata T.; Donadi, Eduardo A.; Tost, Jörg; Daunay, Antoine; de Almeida, Bibiana Sgorla; Carosella, Edgardo D.; Moreau, Philippe

    2016-01-01

    HLA-G is an immune checkpoint molecule with specific relevance in cancer immunotherapy. It was first identified in cytotrophoblasts, protecting the fetus from maternal rejection. HLA-G tissue expression is very restricted but induced in numerous malignant tumors such as glioblastoma, contributing to their immune escape. Hypoxia occurs during placenta and tumor development and was shown to activate HLA-G. We aimed to elucidate the mechanisms of HLA-G activation under conditions combining hypoxia-mimicking treatment and 5-aza-2′deoxycytidine, a DNA demethylating agent used in anti-cancer therapy which also induces HLA-G. Both treatments enhanced the amount of HLA-G mRNA and protein in HLA-G negative U251MG glioma cells. Electrophoretic Mobility Shift Assays and luciferase reporter gene assays revealed that HLA-G upregulation depends on Hypoxia Inducible Factor-1 (HIF-1) and a hypoxia responsive element (HRE) located in exon 2. A polymorphic HRE at −966 bp in the 5′UT region may modulate the magnitude of the response mediated by the exon 2 HRE. We suggest that therapeutic strategies should take into account that HLA-G expression in response to hypoxic tumor environment is dependent on HLA-G gene polymorphism and DNA methylation state at the HLA-G locus. PMID:27577073

  19. Hypoxia inducible factor-1 mediates the expression of the immune checkpoint HLA-G in glioma cells through hypoxia response element located in exon 2.

    PubMed

    Yaghi, Layale; Poras, Isabelle; Simoes, Renata T; Donadi, Eduardo A; Tost, Jörg; Daunay, Antoine; de Almeida, Bibiana Sgorla; Carosella, Edgardo D; Moreau, Philippe

    2016-09-27

    HLA-G is an immune checkpoint molecule with specific relevance in cancer immunotherapy. It was first identified in cytotrophoblasts, protecting the fetus from maternal rejection. HLA-G tissue expression is very restricted but induced in numerous malignant tumors such as glioblastoma, contributing to their immune escape. Hypoxia occurs during placenta and tumor development and was shown to activate HLA-G. We aimed to elucidate the mechanisms of HLA-G activation under conditions combining hypoxia-mimicking treatment and 5-aza-2'deoxycytidine, a DNA demethylating agent used in anti-cancer therapy which also induces HLA-G. Both treatments enhanced the amount of HLA-G mRNA and protein in HLA-G negative U251MG glioma cells. Electrophoretic Mobility Shift Assays and luciferase reporter gene assays revealed that HLA-G upregulation depends on Hypoxia Inducible Factor-1 (HIF-1) and a hypoxia responsive element (HRE) located in exon 2. A polymorphic HRE at -966 bp in the 5'UT region may modulate the magnitude of the response mediated by the exon 2 HRE. We suggest that therapeutic strategies should take into account that HLA-G expression in response to hypoxic tumor environment is dependent on HLA-G gene polymorphism and DNA methylation state at the HLA-G locus.

  20. Two-Component Elements Mediate Interactions between Cytokinin and Salicylic Acid in Plant Immunity

    PubMed Central

    Argueso, Cristiana T.; Ferreira, Fernando J.; Epple, Petra; To, Jennifer P. C.; Hutchison, Claire E.; Schaller, G. Eric; Dangl, Jeffery L.; Kieber, Joseph J.

    2012-01-01

    Recent studies have revealed an important role for hormones in plant immunity. We are now beginning to understand the contribution of crosstalk among different hormone signaling networks to the outcome of plant–pathogen interactions. Cytokinins are plant hormones that regulate development and responses to the environment. Cytokinin signaling involves a phosphorelay circuitry similar to two-component systems used by bacteria and fungi to perceive and react to various environmental stimuli. In this study, we asked whether cytokinin and components of cytokinin signaling contribute to plant immunity. We demonstrate that cytokinin levels in Arabidopsis are important in determining the amplitude of immune responses, ultimately influencing the outcome of plant–pathogen interactions. We show that high concentrations of cytokinin lead to increased defense responses to a virulent oomycete pathogen, through a process that is dependent on salicylic acid (SA) accumulation and activation of defense gene expression. Surprisingly, treatment with lower concentrations of cytokinin results in increased susceptibility. These functions for cytokinin in plant immunity require a host phosphorelay system and are mediated in part by type-A response regulators, which act as negative regulators of basal and pathogen-induced SA–dependent gene expression. Our results support a model in which cytokinin up-regulates plant immunity via an elevation of SA–dependent defense responses and in which SA in turn feedback-inhibits cytokinin signaling. The crosstalk between cytokinin and SA signaling networks may help plants fine-tune defense responses against pathogens. PMID:22291601

  1. Hormone stimulation of androgen receptor mediates dynamic changes in DNA methylation patterns at regulatory elements

    PubMed Central

    Dhiman, Vineet K.; Attwood, Kristopher; Campbell, Moray J.; Smiraglia, Dominic J.

    2015-01-01

    DNA methylation is an epigenetic modification that contributes to stable gene silencing by interfering with the ability of transcriptional regulators to bind to DNA. Recent findings have revealed that hormone stimulation of certain nuclear receptors induces rapid, dynamic changes in DNA methylation patterns alongside transcriptional responses at a subset of target loci, over time. However, the ability of androgen receptor (AR) to dynamically regulate gene transcription is relatively under-studied and its role in the regulation of DNA methylation patterns remains to be elucidated. Here we demonstrate in normal prostate cells that hormone stimulated AR activity results in dynamic changes in the transcription rate and DNA methylation patterns at the AR target genes, TIPARP and SGK1. Time-resolved chromatin immunoprecipitation experiments on the SGK1 locus reveals dynamic recruitment of AR and RNA Polymerase II, as well as the recruitment of proteins involved in the DNA demethylation process, TET1 and TDG. Furthermore, the presence of DNA methylation at dynamic regions inhibits protein binding and transcriptional activity of SGK1. These findings establish AR activity as a contributing factor to the dynamic regulation of DNA methylation patterns at target genes in prostate biology and infer further complexity involved in nuclear receptor mediation of transcriptional regulation. PMID:26646795

  2. USP7 Enforces Heterochromatinization of p53 Target Promoters by Protecting SUV39H1 from MDM2-Mediated Degradation.

    PubMed

    Mungamuri, Sathish Kumar; Qiao, Rui F; Yao, Shen; Manfredi, James J; Gu, Wei; Aaronson, Stuart A

    2016-03-22

    The H3K9me3 repressive histone conformation of p53 target promoters is abrogated in response to p53 activation by MDM2-mediated SUV39H1 degradation. Here, we present evidence that the USP7 deubiquitinase protects SUV39H1 from MDM2-mediated ubiquitination in the absence of p53 stimulus. USP7 occupies p53 target promoters in unstressed conditions, a process that is abrogated with p53 activation associated with loss of the H3K9me3 mark on these same promoters. Mechanistically, USP7 forms a trimeric complex with MDM2 and SUV39H1, independent of DNA, and modulates MDM2-dependent SUV39H1 ubiquitination. Furthermore, we show that this protective function of USP7 on SUV39H1 is independent of p53. Finally, USP7 blocking cooperates with p53 in inducing apoptosis by enhancing p53 promoter occupancy and dependent transactivation of target genes. These results uncover a layer of the p53 transcriptional program mediated by USP7, which restrains relaxation of local chromatin conformation at p53 target promoters. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  3. Physical disruption of skin during poxvirus immunization is critical for the generation of highly protective T cell-mediated immunity

    PubMed Central

    Liu, Luzheng; Zhong, Qiong; Tian, Tian; Dubin, Krista; Athale, Shruti K.; Kupper, Thomas S.

    2010-01-01

    Introductory Paragraph Variola major infection (Smallpox) claimed hundreds of millions lives before it was eradicated by a simple vaccination strategy: epicutaneous application of the related orthopoxvirus Vaccinia virus (VACV) to superficially injured skin (skin scarification, s.s.)1. However, the remarkable success of this strategy was attributed to the immunogenicity of VACV rather than the unique vaccine delivery mode. We now demonstrate that VACV immunization via s.s., but not conventional injection routes, is essential to the generation of superior T cell-mediated immune responses that provide complete protection against subsequent challenges, independent of neutralizing antibodies. Skin-resident effector memory T cells (TEM) provide complete protection against cutaneous challenge, while protection against lethal respiratory challenge requires both respiratory mucosal TEM and central memory T cells (TCM). Vaccination with recombinant VACV (rVACV) expressing a tumor antigen was protective against tumor challenge only if delivered via s.s. route, but not by hypodermic injection. Finally, the clinically safer non-replicative Modified Vaccinia Ankara (MVA) also generated far superior protective immunity when delivered via s.s route compared to intramuscular injection used in MVA clinical trials. Thus, delivering rVACV -based vaccines, including MVA vaccines, through physically disrupted epidermis represents a uniquely powerful strategy with clear-cut advantages over conventional vaccination via hypodermic injection. PMID:20081864

  4. Crucial sequences within the Epstein-Barr virus TP1 promoter for EBNA2-mediated transactivation and interaction of EBNA2 with its responsive element.

    PubMed Central

    Meitinger, C; Strobl, L J; Marschall, G; Bornkamm, G W; Zimber-Strobl, U

    1994-01-01

    EBNA2 is one of the few genes of Epstein-Barr virus which are necessary for immortalization of human primary B lymphocytes. The EBNA2 protein acts as a transcriptional activator of several viral and cellular genes. For the TP1 promoter, we have shown previously that an EBNA2-responsive element (EBNA2RE) between -258 and -177 relative to the TP1 RNA start site is necessary and sufficient for EBNA2-mediated transactivation and that it binds EBNA2 through a cellular factor. To define the critical cis elements within this region, we cloned EBNA2RE mutants in front of the TP1 minimal promoter fused to the reporter gene for luciferase. Transactivation by EBNA2 was tested by transfection of these mutants in the absence and presence of an EBNA2 expression vector into the established B-cell line BL41-P3HR-1. The analysis revealed that two identical 11-bp motifs and the region 3' of the second 11-bp motif are essential for transactivation by EBNA2. Methylation interference experiments indicated that the same cellular factor in the absence of EBNA2 binds either one (complex I) or both (complex III) 11-bp motifs with different affinities, giving rise to two different specific protein-DNA complexes within the left-hand 54 bp of EBNA2RE. A third specific complex was shown previously to be present only in EBNA2-expressing cells and to contain EBNA2. Analysis of this EBNA2-containing complex revealed the same protection pattern as for complex III, indicating that EBNA2 interacts with DNA through binding of the cellular protein to the 11-bp motifs. Mobility shift assays with the different mutants demonstrated that one 11-bp motif is sufficient for binding the cellular factor, whereas for binding of EBNA2 as well as for efficient transactivation by EBNA2, both 11-bp motifs are required. Images PMID:7933133

  5. Protection against acetaminophen-induced liver injury by allopurinol is dependent on aldehyde oxidase-mediated liver preconditioning.

    PubMed

    Williams, C David; McGill, Mitchell R; Lebofsky, Margitta; Bajt, Mary Lynn; Jaeschke, Hartmut

    2014-02-01

    Acetaminophen (APAP) overdose causes severe and occasionally fatal liver injury. Numerous drugs that attenuate APAP toxicity have been described. However these compounds frequently protect by cytochrome P450 inhibition, thereby preventing the initiating step of toxicity. We have previously shown that pretreatment with allopurinol can effectively protect against APAP toxicity, but the mechanism remains unclear. In the current study, C3HeB/FeJ mice were administered allopurinol 18h or 1h prior to an APAP overdose. Administration of allopurinol 18h prior to APAP overdose resulted in an 88% reduction in liver injury (serum ALT) 6h after APAP; however, 1h pretreatment offered no protection. APAP-cysteine adducts and glutathione depletion kinetics were similar with or without allopurinol pretreatment. The phosphorylation and mitochondrial translocation of c-jun-N-terminal-kinase (JNK) have been implicated in the progression of APAP toxicity. In our study we showed equivalent early JNK activation (2h) however late JNK activation (6h) was attenuated in allopurinol treated mice, which suggests that later JNK activation is more critical for the toxicity. Additional mice were administered oxypurinol (primary metabolite of allopurinol) 18h or 1h pre-APAP, but neither treatment protected. This finding implicated an aldehyde oxidase (AO)-mediated metabolism of allopurinol, so mice were treated with hydralazine to inhibit AO prior to allopurinol/APAP administration, which eliminated the protective effects of allopurinol. We evaluated potential targets of AO-mediated preconditioning and found increased hepatic metallothionein 18h post-allopurinol. These data show metabolism of allopurinol occurring independent of P450 isoenzymes preconditions the liver and renders the animal less susceptible to an APAP overdose. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Protective role of p21(Waf1/Cip1) against prostaglandin A2-mediated apoptosis of human colorectal carcinoma cells.

    PubMed Central

    Gorospe, M; Wang, X; Guyton, K Z; Holbrook, N J

    1996-01-01

    Prostaglandin A2 (PGA2) suppresses tumor growth in vivo, is potently antiproliferative in vitro, and is a model drug for the study of the mammalian stress response. Our previous studies using breast carcinoma MCF-7 cells suggested that p21(Waf1/Cip1) induction enabled cells to survive PGA2 exposure. Indeed, the marked sensitivity of human colorectal carcinoma RKO cells to the cytotoxicity of PGA2 is known to be associated with a lack of a PGA2-mediated increase in p21(Waf1/Cip1) expression, inhibition of cyclin-dependent kinase activity, and growth arrest. To determine if cell death following exposure to PGA2 could be prevented by forcing the expression of p21(Waf1/Cip1) in RKO cells, we utilized an adenoviral vector-based expression system. We demonstrate that ectopic expression of p21(Waf1/Cip1) largely rescued RKO cells from PGA2-induced apoptotic cell death, directly implicating p21(Waf1/Cip1) as a determinant of the cellular outcome (survival versus death) following exposure to PGA2. To discern whether p21(Waf1/Cip1)-mediated protection operates through the implementation of cellular growth arrest, other growth-inhibitory treatments were studied for the ability to attenuate PGA2-induced cell death. Neither serum depletion nor suramin (a growth factor receptor antagonist) protected RKO cells against PGA2 cytotoxicity, and neither induced p21(Waf1/Cip1) expression. Mimosine, however, enhanced p21(Waf1/Cip1) expression, completely inhibited RKO cell proliferation, and exerted marked protection against a subsequent PGA2 challenge. Taken together, our results directly demonstrate a protective role for p21(Waf1/Cip1) during PGA2 cellular stress and provide strong evidence that the implementation of cellular growth arrest contributes to this protective influence. PMID:8943319

  7. Role of the Tumor Suppressor PTEN in Antioxidant Responsive Element-mediated Transcription and Associated Histone Modifications

    PubMed Central

    Sakamoto, Kensuke; Iwasaki, Kenta; Sugiyama, Hiroyuki

    2009-01-01

    Coordinated regulation of PI3-kinase (PI3K) and the tumor suppressor phosphatase and tensin homologue deleted on chromosome 10 (PTEN) plays a pivotal role in various cell functions. PTEN is deficient in many cancer cells, including Jurkat human leukemia. Here, we demonstrate that the status of PTEN determines cellular susceptibility to oxidative stress through antioxidant-responsive element (ARE)-mediated transcription of detoxification genes. We found that ferritin H transcription was robustly induced in tert-butylhydroquinone (t-BHQ)-treated Jurkat cells via an ARE, and it was due to PTEN deficiency. Chromatin immunoprecipitation assays revealed that p300/CREB-binding protein (CBP) histone acetyltransferases and Nrf2 recruitment to the ARE and Bach1 release were blocked by the PI3K inhibitor LY294002, along with the partial inhibition of Nrf2 nuclear accumulation. Furthermore, acetylations of histone H3 Lys9 and Lys18, and deacetylation of Lys14 were associated with the PI3K-dependent ARE activation. Consistently, PTEN restoration in Jurkat cells inhibited t-BHQ–mediated expression of ferritin H and another ARE-regulated gene NAD(P)H:quinone oxidoreductase 1. Conversely, PTEN knockdown in K562 cells enhanced the response to t-BHQ. The PTEN status under t-BHQ treatment affected hydrogen peroxide-mediated caspase-3 cleavage. The PI3K-dependent ferritin H induction was observed by treatment with other ARE-activating agents ethoxyquin and hemin. Collectively, the status of PTEN determines chromatin modifications leading to ARE activation. PMID:19158375

  8. Cyclic adenosine monophosphate-response element-binding protein mediates the proangiogenic or proinflammatory activity of gremlin.

    PubMed

    Corsini, Michela; Moroni, Emanuela; Ravelli, Cosetta; Andrés, Germán; Grillo, Elisabetta; Ali, Imran H; Brazil, Derek P; Presta, Marco; Mitola, Stefania

    2014-01-01

    Angiogenesis and inflammation are closely related processes. Gremlin is a novel noncanonical vascular endothelial growth factor receptor-2 (VEGFR2) ligand that induces a proangiogenic response in endothelial cells (ECs). Here, we investigated the role of the cyclic adenosine monophosphate-response element (CRE)-binding protein (CREB) in mediating the proinflammatory and proangiogenic responses of ECs to gremlin. Gremlin induces a proinflammatory response in ECs, leading to reactive oxygen species and cyclic adenosine monophosphate production and the upregulation of proinflammatory molecules involved in leukocyte extravasation, including chemokine (C-C motif) ligand-2 (Ccl2) and Ccl7, chemokine (C-X-C motif) ligand-1 (Cxcl1), vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1). Accordingly, gremlin induces the VEGFR2-dependent phosphorylation, nuclear translocation, and transactivating activity of CREB in ECs. CREB activation mediates the early phases of the angiogenic response to gremlin, including stimulation of EC motility and permeability, and leads to monocyte/macrophage adhesion to ECs and their extravasation. All these effects are inhibited by EC transfection with a dominant-negative CREB mutant or with a CREB-binding protein-CREB interaction inhibitor that competes for CREB/CRE binding. Also, both recombinant gremlin and gremlin-expressing tumor cells induce proinflammatory/proangiogenic responses in vivo that are suppressed by the anti-inflammatory drug hydrocortisone. Similar effects were induced by the canonical VEGFR2 ligand VEGF-A165. Together, the results underline the tight cross-talk between angiogenesis and inflammation and demonstrate a crucial role of CREB activation in the modulation of the VEGFR2-mediated proinflammatory/proangiogenic response of ECs to gremlin.

  9. Ligand binding to the AMP-activated protein kinase active site mediates protection of the activation loop from dephosphorylation.

    PubMed

    Chandrashekarappa, Dakshayini G; McCartney, Rhonda R; Schmidt, Martin C

    2013-01-04

    The AMP-activated protein kinase (AMPK) is a conserved signaling molecule in a pathway that maintains adenosine triphosphate homeostasis. Recent studies have suggested that low energy adenylate ligands bound to one or more sites in the γ subunit of AMPK promote the formation of an active, phosphatase-resistant conformation. We propose an alternative model in which the kinase domain association with the heterotrimer core results in activation of the kinase catalytic activity, whereas low energy adenylate ligands bound in the kinase active site promote phosphatase resistance. Purified Snf1 α subunit with a conservative, single amino acid substitution in the kinase domain is protected from dephosphorylation by adenosine diphosphate in the complete absence of the β and γ subunits. Staurosporine, a compound known to bind to the active site of many protein kinases, mediates strong protection from dephosphorylation to yeast and mammalian AMPK enzymes. The analog-sensitive Snf1-I132G protein but not wild type Snf1 exhibits protection from dephosphorylation when bound by the adenosine analog 2NM-PP1 in vitro and in vivo. These data demonstrate that ligand binding to the Snf1 active site can mediate phosphatase resistance. Finally, Snf1 kinase with an amino acid substitution at the interface of the kinase domain and the heterotrimer core exhibits normal regulation of phosphorylation in vivo but greatly reduced Snf1 kinase activity, supporting a model in which kinase domain association with the heterotrimer core is needed for kinase activation.

  10. Elements involved in S-adenosylmethionine-mediated regulation of the Saccharomyces cerevisiae MET25 gene.

    PubMed Central

    Thomas, D; Cherest, H; Surdin-Kerjan, Y

    1989-01-01

    In Saccharomyces cerevisiae, the MET25 gene encodes O-acetylhomoserine sulfhydrylase. Synthesis of this enzyme is repressed by the presence of S-adenosylmethionine (AdoMet) in the growth medium. We identified cis elements required for MET25 expression by analyzing small deletions in the MET25 promoter region. The results revealed a regulatory region, acting as an upstream activation site, that activated transcription of MET25 in the absence of methionine or AdoMet. We found that, for the most part, repression of MET25 expression was due to a lack of activation at this site, reinforced by an independent repression mechanism. The activation region contained a repeated dyad sequence that is also found in the promoter regions of other unlinked but coordinately regulated genes (MET3, MET2, and SAM2). We show that the presence of the two dyads is necessary for maximal gene expression. Moreover, we demonstrate that in addition to this transcriptional regulation, a posttranscriptional regulation, probably targeted at the 5' region of mRNA, is involved in MET25 expression. Images PMID:2552290

  11. Silencing near tRNA genes is nucleosome-mediated and distinct from boundary element function

    PubMed Central

    Good, Paul D.; Kendall, Ann; Ignatz-Hoover, James; Miller, Erin L.; Pai, Dave A.; Rivera, Sara R.; Carrick, Brian; Engelke, David R.

    2013-01-01

    Transfer RNA (tRNA) genes and other RNA polymerase III transcription units are dispersed in high copy throughout nuclear genomes, and can antagonize RNA polymerase II transcription in their immediate chromosomal locus. Previous work in Saccharomyces cerevisiae found that this local silencing required subnuclear clustering of the tRNA genes near the nucleolus. Here we show that the silencing also requires nucleosome participation, though the nature of the nucleosome interaction appears distinct from other forms of transcriptional silencing. Analysis of an extensive library of histone amino acid substitutions finds a large number of residues that affect the silencing, both in the histone N-terminal tails and on the nucleosome disk surface. The residues on the disk surfaces involved are largely distinct from those affecting other regulatory phenomena. Consistent with the large number of histone residues affecting tgm silencing, survey of chromatin modification mutations shows that several enzymes known to affect nucleosome modification and positioning are also required. The enzymes include an Rpd3 deacetylase complex, Hos1 deacetylase, Glc7 phosphatase, and the RSC nucleosome remodeling activity, but not multiple other activities required for other silencing forms or boundary element function at tRNA gene loci. Models for communication between the tRNA gene transcription complexes and local chromatin are discussed. PMID:23707796

  12. Silencing near tRNA genes is nucleosome-mediated and distinct from boundary element function.

    PubMed

    Good, Paul D; Kendall, Ann; Ignatz-Hoover, James; Miller, Erin L; Pai, Dave A; Rivera, Sara R; Carrick, Brian; Engelke, David R

    2013-08-15

    Transfer RNA (tRNA) genes and other RNA polymerase III transcription units are dispersed in high copy throughout nuclear genomes, and can antagonize RNA polymerase II transcription in their immediate chromosomal locus. Previous work in Saccharomyces cerevisiae found that this local silencing required subnuclear clustering of the tRNA genes near the nucleolus. Here we show that the silencing also requires nucleosome participation, though the nature of the nucleosome interaction appears distinct from other forms of transcriptional silencing. Analysis of an extensive library of histone amino acid substitutions finds a large number of residues that affect the silencing, both in the histone N-terminal tails and on the nucleosome disk surface. The residues on the disk surfaces involved are largely distinct from those affecting other regulatory phenomena. Consistent with the large number of histone residues affecting tgm silencing, survey of chromatin modification mutations shows that several enzymes known to affect nucleosome modification and positioning are also required. The enzymes include an Rpd3 deacetylase complex, Hos1 deacetylase, Glc7 phosphatase, and the RSC nucleosome remodeling activity, but not multiple other activities required for other silencing forms or boundary element function at tRNA gene loci. Models for communication between the tRNA gene transcription complexes and local chromatin are discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Intronic elements in the Na+/I- symporter gene (NIS) interact with retinoic acid receptors and mediate initiation of transcription

    PubMed Central

    Alotaibi, Hani; Yaman, Elif; Salvatore, Domenico; Di Dato, Valeria; Telkoparan, Pelin; Di Lauro, Roberto; Tazebay, Uygar H.

    2010-01-01

    Activity of the sodium/iodide symporter (NIS) in lactating breast is essential for iodide (I–) accumulation in milk. Significant NIS upregulation was also reported in breast cancer, indicating a potential use of radioiodide treatment. All-trans-retinoic acid (tRA) is a potent ligand that enhances NIS expression in a subset of breast cancer cell lines and in experimental breast cancer models. Indirect tRA stimulation of NIS in breast cancer cells is very well documented; however, direct upregulation by tRA-activated nuclear receptors has not been identified yet. Aiming to uncover cis-acting elements directly regulating NIS expression, we screened evolutionary-conserved non-coding genomic sequences for responsiveness to tRA in MCF-7. Here, we report that a potent enhancer in the first intron of NIS mediates direct regulation by tRA-stimulated nuclear receptors. In vitro as well as in vivo DNA–protein interaction assays revealed direct association between retinoic acid receptor-α (RARα) and retinoid-X-receptor (RXR) with this enhancer. Moreover, using chromatin immunoprecipitation (ChIP) we uncovered early events of NIS transcription in response to tRA, which require the interaction of several novel intronic tRA responsive elements. These findings indicate a complex interplay between nuclear receptors, RNA Pol-II and multiple intronic RAREs in NIS gene, and they establish a novel mechanistic model for tRA-induced gene transcription. PMID:20123735

  14. Intronic elements in the Na+/I- symporter gene (NIS) interact with retinoic acid receptors and mediate initiation of transcription.

    PubMed

    Alotaibi, Hani; Yaman, Elif; Salvatore, Domenico; Di Dato, Valeria; Telkoparan, Pelin; Di Lauro, Roberto; Tazebay, Uygar H

    2010-06-01

    Activity of the sodium/iodide symporter (NIS) in lactating breast is essential for iodide (I(-)) accumulation in milk. Significant NIS upregulation was also reported in breast cancer, indicating a potential use of radioiodide treatment. All-trans-retinoic acid (tRA) is a potent ligand that enhances NIS expression in a subset of breast cancer cell lines and in experimental breast cancer models. Indirect tRA stimulation of NIS in breast cancer cells is very well documented; however, direct upregulation by tRA-activated nuclear receptors has not been identified yet. Aiming to uncover cis-acting elements directly regulating NIS expression, we screened evolutionary-conserved non-coding genomic sequences for responsiveness to tRA in MCF-7. Here, we report that a potent enhancer in the first intron of NIS mediates direct regulation by tRA-stimulated nuclear receptors. In vitro as well as in vivo DNA-protein interaction assays revealed direct association between retinoic acid receptor-alpha (RARalpha) and retinoid-X-receptor (RXR) with this enhancer. Moreover, using chromatin immunoprecipitation (ChIP) we uncovered early events of NIS transcription in response to tRA, which require the interaction of several novel intronic tRA responsive elements. These findings indicate a complex interplay between nuclear receptors, RNA Pol-II and multiple intronic RAREs in NIS gene, and they establish a novel mechanistic model for tRA-induced gene transcription.

  15. Far upstream element-binding protein 1 and RNA secondary structure both mediate second-step splicing repression

    PubMed Central

    Li, Huang; Wang, Zhijia; Zhou, Xuexia; Cheng, Yuanming; Xie, Zhiqin; Manley, James L.; Feng, Ying

    2013-01-01

    Splicing of mRNA precursors consists of two steps that are almost invariably tightly coupled to facilitate efficient generation of spliced mRNA. However, we described previously a splicing substrate that is completely blocked after the first step. We have now investigated the basis for this unusual second-step inhibition and unexpectedly elucidated two independent mechanisms. One involves a stem–loop structure located downstream of the 3′splice site, and the other involves an exonic splicing silencer (ESS) situated 3′ to the structure. Both elements contribute to the second-step block in vitro and also cause exon skipping in vivo. Importantly, we identified far upstream element-binding protein 1 (FUBP1), a single-stranded DNA- and RNA-binding protein not previously implicated in splicing, as a strong ESS binding protein, and several assays implicate it in ESS function. We demonstrate using depletion/add-back experiments that FUBP1 acts as a second-step repressor in vitro and show by siRNA-mediated knockdown and overexpression assays that it modulates exon inclusion in vivo. Together, our results provide additional insights into splicing control, and identify FUBP1 as a splicing regulator. PMID:23818605

  16. Far upstream element-binding protein 1 and RNA secondary structure both mediate second-step splicing repression.

    PubMed

    Li, Huang; Wang, Zhijia; Zhou, Xuexia; Cheng, Yuanming; Xie, Zhiqin; Manley, James L; Feng, Ying

    2013-07-16

    Splicing of mRNA precursors consists of two steps that are almost invariably tightly coupled to facilitate efficient generation of spliced mRNA. However, we described previously a splicing substrate that is completely blocked after the first step. We have now investigated the basis for this unusual second-step inhibition and unexpectedly elucidated two independent mechanisms. One involves a stem-loop structure located downstream of the 3'splice site, and the other involves an exonic splicing silencer (ESS) situated 3' to the structure. Both elements contribute to the second-step block in vitro and also cause exon skipping in vivo. Importantly, we identified far upstream element-binding protein 1 (FUBP1), a single-stranded DNA- and RNA-binding protein not previously implicated in splicing, as a strong ESS binding protein, and several assays implicate it in ESS function. We demonstrate using depletion/add-back experiments that FUBP1 acts as a second-step repressor in vitro and show by siRNA-mediated knockdown and overexpression assays that it modulates exon inclusion in vivo. Together, our results provide additional insights into splicing control, and identify FUBP1 as a splicing regulator.

  17. Negative regulation of transcription in vitro by a glucocorticoid response element is mediated by a trans-acting factor.

    PubMed Central

    Langer, S J; Ostrowski, M C

    1988-01-01

    In vitro experiments with cell extracts prepared from a mouse mammary epithelial cell line demonstrated that a cis-acting glucocorticoid response element (GRE) of the mouse mammary tumor virus represses transcription from its homologous promoter. Competition transcription experiments, in which a molar excess of a restriction fragment that contains the GRE is added to the cell-free assay, revealed that a nuclear factor mediates in trans the negative regulation of mammary tumor virus transcription in vitro. Gel retention assays indicated that a factor in the extracts specifically recognizes the GRE. One unusual result of the gel retention studies was that heating the GRE probe to 65 degrees C before addition to a binding assay increases the formation of the specific protein-DNA complex 20-fold. Exonuclease III footprinting demonstrated that the sequences recognized by the factor are identical for either untreated or heat-treated probe. The footprinting also demonstrated that this factor recognizes sequences that are distinct from those recognized by the glucocorticoid receptor. A synthetic oligonucleotide based on the sequences identified by the footprinting experiments repressed the activity of a heterologous enhancer-promoter in vivo, as assayed by transient expression assays. We propose that this negative transcription element may control the basal level of expression of some glucocorticoid-modulated genes and may explain the insensitivity of certain tumor cells to steroid hormone action. Images PMID:2851730

  18. Neuronal development genes are key elements mediating the reinforcing effects of methamphetamine, amphetamine, and methylphenidate.

    PubMed

    Dela Peña, Ike; Jeon, Se Jin; Lee, Eunyoung; Ryu, Jong Hoon; Shin, Chan Young; Noh, Minsoo; Cheong, Jae Hoon

    2013-12-01

    The molecular mechanisms underlying susceptibility to psychostimulant addiction remain unclear. Searching for commonalities in the effects of addictive drugs on brain gene expression is a prolific approach to determine transcriptional signatures influencing drug abuse. We explored the common transcriptional responses to the reinforcing effects of psychostimulants methamphetamine, amphetamine, and methylphenidate. We also aimed to identify transcriptional changes that may subserve abuse of these drugs. Genome-wide transcriptome profiling analyses were performed to identify common prefrontal cortical (PFC) and striatal gene expression profiles in drug-naïve (cohort 1) and stimulant-pretreated (cohort 2) rats, which showed a conditioned place preference to and self-administration of methamphetamine, amphetamine, and methylphenidate. In behavioral studies, stimulant-pretreated rats showed behavioral sensitization characterized by enhanced behavioral response to the rewarding or reinforcing effects of psychostimulants. Inflammation-associated genes (e.g., Alas1, S100a8 and S100a9) were identified as the primary differentially expressed genes (DEGs) in both the PFC and the striatum of cohort 1 rats, while neuronal plasticity (Sgk1)- and brain development (e.g., Bhlhe22, Neurod1, Nr4a2, and Msx1)-associated genes comprised the major upregulated DEGs in the striatum of cohort 2 rats. Furthermore, a meta-analysis of the common striatal DEGs in this study along with morphine-regulated striatal transcriptomes in mice (National Center for Biotechnology Information-Gene Expression Omnibus Database Accession Code GSE7762) suggested similar expression profiles of genes involved in neuronal development (e.g., Bhlhe22, Nr4a2). This study provides evidence that brain development-associated genes mediate the reinforcing effects of methamphetamine, amphetamine, and methylphenidate and that these transcripts may underlie susceptibility to psychostimulant addiction.

  19. Neutralizing IgG at the portal of infection mediates protection against vaginal simian/human immunodeficiency virus challenge.

    PubMed

    Klein, Katja; Veazey, Ronald S; Warrier, Ranjit; Hraber, Peter; Doyle-Meyers, Lara A; Buffa, Viviana; Liao, Hua-Xin; Haynes, Barton F; Shaw, George M; Shattock, Robin J

    2013-11-01

    Neutralizing antibodies may have critical importance in immunity against human immunodeficiency virus type 1 (HIV-1) infection. However, the amount of protective antibody needed at mucosal surfaces has not been fully established. Here, we evaluated systemic and mucosal pharmacokinetics (PK) and pharmacodynamics (PD) of 2F5 IgG and 2F5 Fab fragments with respect to protection against vaginal challenge with simian-human immunodeficiency virus-BaL in macaques. Antibody assessment demonstrated that 2F5 IgG was more potent than polymeric forms (IgM and IgA) across a range of cellular and tissue models. Vaginal challenge studies demonstrated a dose-dependent protection for 2F5 IgG and no protection with 2F5 Fab despite higher vaginal Fab levels at the time of challenge. Animals receiving 50 or 25 mg/kg of body weight 2F5 IgG were completely protected, while 3/5 animals receiving 5 mg/kg were protected. In the control animals, infection was established by a minimum of 1 to 4 transmitted/founder (T/F) variants, similar to natural human infection by this mucosal route; in the two infected animals that had received 5 mg 2F5 IgG, infection was established by a single T/F variant. Serum levels of 2F5 IgG were more predictive of sterilizing protection than measured vaginal levels. Fc-mediated antiviral activity did not appear to influence infection of primary target cells in cervical explants. However, PK studies highlighted the importance of the Fc portion in tissue biodistribution. Data presented in this study may be important in modeling serum levels of neutralizing antibodies that need to be achieved by either vaccination or passive infusion to prevent mucosal acquisition of HIV-1 infection in humans.

  20. Cross Protective Mucosal Immunity Mediated by Memory Th17 Cells against Streptococcus pneumoniae Lung Infection

    PubMed Central

    Wang, Yan; Jiang, Bin; Guo, Yongli; Li, Wenchao; Tian, Ying; Sonnenberg, Gregory F; Weiser, Jeffery N.; Ni, Xin; Shen, Hao

    2016-01-01

    Pneumonia caused by Streptococcus pneumoniae (Sp) remains a leading cause of serious illness and death worldwide. Immunization with conjugated pneumococcal vaccine has lowered the colonization rate and consequently invasive diseases by inducing serotype-specific antibodies. However, many of current pneumonia cases result from infection by serotype strains not included in the vaccine. In this study, we asked if cross-protection against lung infection by heterologous strains can be induced and investigated the underlying immune mechanism. We found that immune mice recovered from a prior infection were protected against heterologous Sp strains in the pneumonia challenge model, as evident by accelerated bacterial clearance, reduced pathology and apoptosis of lung epithelial cells. Sp infection in the lung induced strong Th17 responses at the lung mucosal site. Transfer of CD4+ T cells from immune mice provided heterologous protection against pneumonia, and this protection was abrogated by IL-17A blockade. Transfer of memory CD4+ T cells from IL-17A knockout mice failed to provide protection. These results indicate that memory Th17 cells played a key role in providing protection against pneumonia in a serotype independent manner and suggest the feasibility of developing a broadly protective vaccine against bacterial pneumonia by targeting mucosal Th17 T cells. PMID:27118490

  1. Recombinant vesicular stomatitis virus vector mediates postexposure protection against Sudan Ebola hemorrhagic fever in nonhuman primates.

    PubMed

    Geisbert, Thomas W; Daddario-DiCaprio, Kathleen M; Williams, Kinola J N; Geisbert, Joan B; Leung, Anders; Feldmann, Friederike; Hensley, Lisa E; Feldmann, Heinz; Jones, Steven M

    2008-06-01

    Recombinant vesicular stomatitis virus (VSV) vectors expressing homologous filoviral glycoproteins can completely protect rhesus monkeys against Marburg virus when administered after exposure and can partially protect macaques after challenge with Zaire ebolavirus. Here, we administered a VSV vector expressing the Sudan ebolavirus (SEBOV) glycoprotein to four rhesus macaques shortly after exposure to SEBOV. All four animals survived SEBOV challenge, while a control animal that received a nonspecific vector developed fulminant SEBOV hemorrhagic fever and succumbed. This is the first demonstration of complete postexposure protection against an Ebola virus in nonhuman primates and provides further evidence that postexposure vaccination may have utility in treating exposures to filoviruses.

  2. Sulfur-Oxidizing Bacteria Mediate Microbial Community Succession and Element Cycling in Launched Marine Sediment

    PubMed Central

    Ihara, Hideyuki; Hori, Tomoyuki; Aoyagi, Tomo; Takasaki, Mitsuru; Katayama, Yoko

    2017-01-01

    A large amount of marine sediment was launched on land by the Great East Japan earthquake. Here, we employed both on-site and laboratory studies on the launched marine sediment to investigate the succession of microbial communities and its effects on geochemical properties of the sediment. Twenty-two-month on-site survey showed that microbial communities at the uppermost layer (0–2 mm depth) of the sediment changed significantly with time, whereas those at the deeper layer (20–40 mm depth) remained nearly unchanged and kept anaerobic microbial communities. Nine months after the incidence, various sulfur-oxidizing bacteria (SOB) prevailed in the uppermost layer, in which afterwards diverse chemoorganotrophic bacteria predominated. Geochemical analyses indicated that the concentration of metals other than Fe was lower in the uppermost layer than that in the deeper layer. Laboratory study was carried out by incubating the sediment for 57 days, and clearly indicated the dynamic transition of microbial communities in the uppermost layer exposed to atmosphere. SOB affiliated in the class Epsilonproteobacteria rapidly proliferated and dominated at the uppermost layer during the first 3 days, after that Fe(II)-oxidizing bacteria and chemoorganotrophic bacteria were sequentially dominant. Furthermore, the concentration of sulfate ion increased and the pH decreased. Consequently, SOB may have influenced the mobilization of heavy metals in the sediment by metal-bound sulfide oxidation and/or sediment acidification. These results demonstrate that SOB initiated the dynamic shift from the anaerobic to aerobic microbial communities, thereby playing a critical role in element cycling in the marine sediment. PMID:28217124

  3. Sulfur-Oxidizing Bacteria Mediate Microbial Community Succession and Element Cycling in Launched Marine Sediment.

    PubMed

    Ihara, Hideyuki; Hori, Tomoyuki; Aoyagi, Tomo; Takasaki, Mitsuru; Katayama, Yoko

    2017-01-01

    A large amount of marine sediment was launched on land by the Great East Japan earthquake. Here, we employed both on-site and laboratory studies on the launched marine sediment to investigate the succession of microbial communities and its effects on geochemical properties of the sediment. Twenty-two-month on-site survey showed that microbial communities at the uppermost layer (0-2 mm depth) of the sediment changed significantly with time, whereas those at the deeper layer (20-40 mm depth) remained nearly unchanged and kept anaerobic microbial communities. Nine months after the incidence, various sulfur-oxidizing bacteria (SOB) prevailed in the uppermost layer, in which afterwards diverse chemoorganotrophic bacteria predominated. Geochemical analyses indicated that the concentration of metals other than Fe was lower in the uppermost layer than that in the deeper layer. Laboratory study was carried out by incubating the sediment for 57 days, and clearly indicated the dynamic transition of microbial communities in the uppermost layer exposed to atmosphere. SOB affiliated in the class Epsilonproteobacteria rapidly proliferated and dominated at the uppermost layer during the first 3 days, after that Fe(II)-oxidizing bacteria and chemoorganotrophic bacteria were sequentially dominant. Furthermore, the concentration of sulfate ion increased and the pH decreased. Consequently, SOB may have influenced the mobilization of heavy metals in the sediment by metal-bound sulfide oxidation and/or sediment acidification. These results demonstrate that SOB initiated the dynamic shift from the anaerobic to aerobic microbial communities, thereby playing a critical role in element cycling in the marine sediment.

  4. A modular system of DNA enhancer elements mediates tissue-specific activation of transcription by high dietary zinc in C. elegans

    PubMed Central

    Roh, Hyun Cheol; Dimitrov, Ivan; Deshmukh, Krupa; Zhao, Guoyan; Warnhoff, Kurt; Cabrera, Daniel; Tsai, Wendy; Kornfeld, Kerry

    2015-01-01

    Zinc is essential for biological systems, and aberrant zinc metabolism is implicated in a broad range of human diseases. To maintain homeostasis in response to fluctuating levels of dietary zinc, animals regulate gene expression; however, mechanisms that mediate the transcriptional response to fluctuating levels of zinc have not been fully defined. Here, we identified DNA enhancer elements that mediate intestine-specific transcriptional activation in response to high levels of dietary zinc in C. elegans. Using bioinformatics, we characterized an evolutionarily conserved enhancer element present in multiple zinc-inducible genes, the high zinc activation (HZA) element. The HZA was consistently adjacent to a GATA element that mediates expression in intestinal cells. Functional studies using transgenic animals demonstrated that this modular system of DNA enhancers mediates tissue-specific transcriptional activation in response to high levels of dietary zinc. We used this information to search the genome and successfully identified novel zinc-inducible genes. To characterize the mechanism of enhancer function, we demonstrated that the GATA transcription factor ELT-2 and the mediator subunit MDT-15 are necessary for zinc-responsive transcriptional activation. These findings define new mechanisms of zinc homeostasis and tissue-specific regulation of transcription. PMID:25552416

  5. A modular system of DNA enhancer elements mediates tissue-specific activation of transcription by high dietary zinc in C. elegans.

    PubMed

    Roh, Hyun Cheol; Dimitrov, Ivan; Deshmukh, Krupa; Zhao, Guoyan; Warnhoff, Kurt; Cabrera, Daniel; Tsai, Wendy; Kornfeld, Kerry

    2015-01-01

    Zinc is essential for biological systems, and aberrant zinc metabolism is implicated in a broad range of human diseases. To maintain homeostasis in response to fluctuating levels of dietary zinc, animals regulate gene expression; however, mechanisms that mediate the transcriptional response to fluctuating levels of zinc have not been fully defined. Here, we identified DNA enhancer elements that mediate intestine-specific transcriptional activation in response to high levels of dietary zinc in C. elegans. Using bioinformatics, we characterized an evolutionarily conserved enhancer element present in multiple zinc-inducible genes, the high zinc activation (HZA) element. The HZA was consistently adjacent to a GATA element that mediates expression in intestinal cells. Functional studies using transgenic animals demonstrated that this modular system of DNA enhancers mediates tissue-specific transcriptional activation in response to high levels of dietary zinc. We used this information to search the genome and successfully identified novel zinc-inducible genes. To characterize the mechanism of enhancer function, we demonstrated that the GATA transcription factor ELT-2 and the mediator subunit MDT-15 are necessary for zinc-responsive transcriptional activation. These findings define new mechanisms of zinc homeostasis and tissue-specific regulation of transcription. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  6. Glycyrrhizin Protects against Acetaminophen-Induced Acute Liver Injury via Alleviating Tumor Necrosis Factor α–Mediated Apoptosis

    PubMed Central

    Yan, Tingting; Wang, Hong; Zhao, Min; Yagai, Tomoki; Chai, Yingying; Krausz, Kristopher W.; Xie, Cen; Cheng, Xuefang; Zhang, Jun; Che, Yuan; Li, Feiyan; Wu, Yuzheng; Brocker, Chad N.; Gonzalez, Frank J.

    2016-01-01

    Acetaminophen (APAP) overdose is the leading cause of drug-induced acute liver failure in Western countries. Glycyrrhizin (GL), a potent hepatoprotective constituent extracted from the traditional Chinese medicine liquorice, has potential clinical use in treating APAP-induced liver failure. The present study determined the hepatoprotective effects and underlying mechanisms of action of GL and its active metabolite glycyrrhetinic acid (GA). Various administration routes and pharmacokinetics–pharmacodynamics analyses were used to differentiate the effects of GL and GA on APAP toxicity in mice. Mice deficient in cytochrome P450 2E1 enzyme (CYP2E1) or receptor interacting protein 3 (RIPK3) and their relative wild-type littermates were subjected to histologic and biochemical analyses to determine the potential mechanisms. Hepatocyte death mediated by tumor necrosis factor α (TNFα)/caspase was analyzed by use of human liver-derived LO2 cells. The pharmacokinetics–pharmacodynamics analysis using various administration routes revealed that GL but not GA potently attenuated APAP-induced liver injury. The protective effect of GL was found only with intraperitoneal and intravenous administration and not with gastric administration. CYP2E1-mediated metabolic activation and RIPK3-mediated necroptosis were unrelated to GL’s protective effect. However, GL inhibited hepatocyte apoptosis via interference with TNFα-induced apoptotic hepatocyte death. These results demonstrate that GL rapidly attenuates APAP-induced liver injury by directly inhibiting TNFα-induced hepatocyte apoptosis. The protective effect against APAP-induced liver toxicity by GL in mice suggests the therapeutic potential of GL for the treatment of APAP overdose. PMID:26965985

  7. Interleukin-19 contributes as a protective factor in experimental Th2-mediated colitis.

    PubMed

    Fujimoto, Yasuyuki; Azuma, Yasu-Taka; Matsuo, Yukiko; Kuwamura, Mitsuru; Kuramoto, Nobuyuki; Miki, Mariko; Azuma, Naoki; Teramoto, Midori; Nishiyama, Kazuhiro; Izawa, Takeshi; Nakajima, Hidemitsu; Takeuchi, Tadayoshi

    2017-03-01

    Inflammatory bowel disease results from chronic dysregulation of the mucosal immune system and aberrant activation of both the innate and adaptive immune responses. IL-19 is a member of the IL-10 family, and IL-10 plays an important role in inflammatory bowel disease. We have previously shown that IL-19 knockout mice are more susceptible to innate-mediated colitis. Next, we ask whether IL-19 contributes to T cells-mediated colitis. Here, we investigated the role of IL-19 in a mouse model of Th2 cell-mediated colitis. Inflammatory responses in IL-19-deficient mice were assessed using a Th2-mediated colitis induced by oxazolone. The colitis was evaluated by analyzing the body weight loss and histology of the colon. Lymph node cells were cultured in vitro to determine cytokine production. IL-19 knockout mice exacerbated oxazolone-induced colitis by stimulating the transport of inflammatory cells into the colon, and by increasing IgE production and the number of circulating eosinophil. The exacerbation of oxazolone-induced colonic inflammation following IL-19 knockout mice was accompanied by an increased production of IL-4 and IL-9, but no changes in the expression of IL-5 and IL-13 in lymph node cells. IL-19 plays an anti-inflammatory role in the Th2-mediated colitis model, suggesting that IL-19 may represent a potential therapeutic target for reducing colonic inflammation.

  8. Vaccine Protection against Bacillus cereus-Mediated Respiratory Anthrax-Like Disease in Mice

    PubMed Central

    Oh, So-Young; Maier, Hannah; Schroeder, Jay; Richter, G. Stefan; Elli, Derek; Musser, James M.; Quenee, Lauriane E.; Missiakas, Dominique M.

    2013-01-01

    Bacillus cereus strains harboring a pXO1-like virulence plasmid cause respiratory anthrax-like disease in humans, particularly in welders. We developed mouse models for intraperitoneal as well as aerosol challenge with spores of B. cereus G9241, harboring pBCXO1 and pBC218 virulence plasmids. Compared to wild-type B. cereus G9241, spores with a deletion of the pBCXO1-carried protective antigen gene (pagA1) were severely attenuated, whereas spores with a deletion of the pBC218-carried protective antigen homologue (pagA2) were not. Anthrax vaccine adsorbed (AVA) immunization raised antibodies that bound and neutralized the pagA1-encoded protective antigen (PA1) but not the PA2 orthologue encoded by pagA2. AVA immunization protected mice against a lethal challenge with spores from B. cereus G9241 or B. cereus Elc4, a strain that had been isolated from a fatal case of anthrax-like disease. As the pathogenesis of B. cereus anthrax-like disease in mice is dependent on pagA1 and PA-neutralizing antibodies provide protection, AVA immunization may also protect humans from respiratory anthrax-like death. PMID:23319564

  9. Dihydromyricetin protects against liver ischemia/reperfusion induced apoptosis via activation of FOXO3a-mediated autophagy

    PubMed Central

    Pi, Huifeng; Qin, Weijia; Chen, Jianwei; Guo, Dengfang; Lin, Jianyu; Chi, Xiaobing; Jiang, Zhelong; Yang, Hejun; Jiang, Yi

    2016-01-01

    Liver ischemia and reperfusion (I/R) injury is characterized by defective liver autophagy accompanied by alterations to the endogenous defense system. Dihydromyricetin (DHM) is a natural flavonoid that demonstrates a wide range of physiological functions, and has been implicated as a regulator of autophagy. This study investigates the protective effects of DHM pretreatment on liver injury caused by ischemia/reperfusion (I/R) and elucidates the potential mechanism of DHM-mediated protection. Mice were subjected to 60 minutes of ischemia followed by 5 hours of reperfusion. DHM (100 mg/kg bw/day) or the vehicle was administered daily by gavage 7 days before ischemia and immediately before reperfusion. In this study, DHM markedly decreased serum aminotransferase activity and inhibited liver I/R -stimulated apoptosis. Moreover, DHM exerted hepatoprotective effects by upregulating mRNA levels of various essential autophagy-related genes including ATG5, ATG12, BECN1, and LC3. Autophagy inhibitor chloroquine or Atg5 knockdown blocked DHM -mediated elevation in liver function. Specifically, DHM significantly increased FOXO3a expression, and enhanced FOXO3a nuclear translocation and Ser588 phosphorylation modification. Importantly, the inhibition of FOXO3a with FOXO3a-siRNA in mice decreased DHM-induced autophagy-related genes and diminished the protective effects of DHM against liver I/R injury. In summary, these findings identify DHM as a novel hepatoprotective small molecule by elevating FOXO3a expression and nuclear translocation, stimulating autophagy-related genes and suppressing liver I/R-induced apoptosis, suggesting FOXO3a may have therapeutic value in liver cell protection in liver I/R injury. PMID:27793014

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

    PubMed

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

    2017-08-02

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

  11. Coenzyme Q10 Protects Astrocytes from ROS-Induced Damage through Inhibition of Mitochondria-Mediated Cell Death Pathway

    PubMed Central

    Jing, Li; He, Mao-Tao; Chang, Yue; Mehta, Suresh L.; He, Qing-Ping; Zhang, Jian-Zhong; Li, P. Andy

    2015-01-01

    Coenzyme Q10 (CoQ10) acts by scavenging reactive oxygen species to protect neuronal cells against oxidative stress in neurodegenerative diseases. The present study was designed to examine whether CoQ10 was capable of protecting astrocytes from reactive oxygen species (ROS) mediated damage. For this purpose, ultraviolet B (UVB) irradiation was used as a tool to induce ROS stress to cultured astrocytes. The cells were treated with 10 and 25 μg/ml of CoQ10 for 3 or 24 h prior to the cells being exposed to UVB irradiation and maintained for 24 h post UVB exposure. Cell viability was assessed by MTT conversion assay. Mitochondrial respiration was assessed by respirometer. While superoxide production and mitochondrial membrane potential were measured using fluorescent probes, levels of cytochrome C (cyto-c), cleaved caspase-9, and caspase-8 were detected using Western blotting and/or immunocytochemistry. The results showed that UVB irradiation decreased cell viability and this damaging effect was associated with superoxide accumulation, mitochondrial membrane potential hyperpolarization, mitochondrial respiration suppression, cyto-c release, and the activation of both caspase-9 and -8. Treatment with CoQ10 at two different concentrations started 24 h before UVB exposure significantly increased the cell viability. The protective effect of CoQ10 was associated with reduction in superoxide, normalization of mitochondrial membrane potential, improvement of mitochondrial respiration, inhibition of cyto-c release, suppression of caspase-9. Furthermore, CoQ10 enhanced mitochondrial biogenesis. It is concluded that CoQ10 may protect astrocytes through suppression of oxidative stress, prevention of mitochondrial dysfunction, blockade of mitochondria-mediated cell death pathway, and enhancement of mitochondrial biogenesis. PMID:25552930

  12. Critical role of IFN-gamma in CFA-mediated protection of NOD mice from diabetes development.

    PubMed

    Mori, Yoshiko; Kodaka, Tetsuro; Kato, Takako; Kanagawa, Edith M; Kanagawa, Osami

    2009-11-01

    IFN-gamma signaling-deficient non-obese diabetic (NOD) mice develop diabetes with similar kinetics to those of wild-type NOD mice. However, the immunization of IFN-gamma signaling-deficient NOD mice with CFA failed to induce long-term protection, whereas wild-type NOD mice receiving CFA remained diabetes-free. CFA also failed to protect IFN-gamma receptor-deficient (IFN-gammaR(-/-)) NOD mice from the autoimmune rejection of transplanted islets, as it does in diabetic NOD mice, and from disease transfer by spleen cells from diabetic NOD mice. These data clearly show that the pro-inflammatory cytokine IFN-gamma is necessary for the CFA-mediated protection of NOD mice from diabetes. There is no difference in the T(h)1/T(h)17 balance between IFN-gammaR(-/-) NOD and wild-type NOD mice. There is also no difference in the total numbers and percentages of regulatory T (Treg) cells in the lymph node CD4(+) T-cell populations between IFN-gammaR(-/-) NOD and wild-type NOD mice. However, pathogenic T cells lacking IFN-gammaR are resistant to the suppressive effect of Treg cells, both in vivo and in vitro. Therefore, it is likely that CFA-mediated protection against diabetes development depends on a change in the balance between Treg cells and pathogenic T cells, and IFN-gamma signaling seems to control the susceptibility of pathogenic T cells to the inhibitory activity of Treg cells.

  13. Metformin Protects Kidney Cells From Insulin-Mediated Genotoxicity In Vitro and in Male Zucker Diabetic Fatty Rats.

    PubMed

    Othman, Eman Maher; Oli, R G; Arias-Loza, Paula-Anahi; Kreissl, Michael C; Stopper, Helga

    2016-02-01

    Hyperinsulinemia is thought to enhance cancer risk. A possible mechanism is induction of oxidative stress and DNA damage by insulin, Here, the effect of a combination of metformin with insulin was investigated in vitro and in vivo. The rationales for this were the reported antioxidative properties of metformin and the aim to gain further insights into the mechanisms responsible for protecting the genome from insulin-mediated oxidative stress and damage. The comet assay, a micronucleus frequency test, and a mammalian gene mutation assay were used to evaluate the DNA damage produced by insulin alone or in combination with metformin. For analysis of antioxidant activity, oxidative stress, and mitochondrial disturbances, the cell-free ferric reducing antioxidant power assay, the superoxide-sensitive dye dihydroethidium, and the mitochondrial membrane potential-sensitive dye 5,5',6,6'tetrachloro-1,1',3,3'-tetraethylbenzimidazol-carbocyanine iodide were applied. Accumulation of p53 and pAKT were analyzed. As an in vivo model, hyperinsulinemic Zucker diabetic fatty rats, additionally exposed to insulin during a hyperinsulinemic-euglycemic clamp, were treated with metformin. In the rat kidney samples, dihydroethidium staining, p53 and pAKT analysis, and quantification of the oxidized DNA base 8-oxo-7,8-dihydro-2'-deoxyguanosine were performed. Metformin did not show intrinsic antioxidant activity in the cell-free assay, but protected cultured cells from insulin-mediated oxidative stress, DNA damage, and mutation. Treatment of the rats with metformin protected their kidneys from oxidative stress and genomic damage induced by hyperinsulinemia. Metformin may protect patients from genomic damage induced by elevated insulin levels. This may support efforts to reduce the elevated cancer risk that is associated with hyperinsulinemia.

  14. Activation of Estrogen Response Element-Independent ERα Signaling Protects Female Mice From Diet-Induced Obesity.

    PubMed

    Yasrebi, Ali; Rivera, Janelle A; Krumm, Elizabeth A; Yang, Jennifer A; Roepke, Troy A

    2017-02-01

    17β-estradiol (E2) regulates central and peripheral mechanisms that control energy and glucose homeostasis predominantly through estrogen receptor α (ERα) acting via receptor binding to estrogen response elements (EREs). ERα signaling is also involved in mediating the effects of E2 on diet-induced obesity (DIO), although the roles of ERE-dependent and -independent ERα signaling in reducing the effects of DIO remain largely unknown. We hypothesize that ERE-dependent ERα signaling is necessary to ameliorate the effects of DIO. We addressed this question using ERα knockout (KO) and ERα knockin/knockout (KIKO) female mice, the latter expressing an ERα that lacks a functional ERE binding domain. Female mice were ovariectomized, fed a low-fat diet (LFD) or a high-fat diet (HFD), and orally dosed with vehicle or estradiol benzoate (EB) (300 μg/kg). After 9 weeks, body composition, glucose and insulin tolerance, peptide hormone and inflammatory cytokine levels, and hypothalamic arcuate nucleus and liver gene expression were assessed. EB reduced body weight and body fat in wild-type (WT) female mice, regardless of diet, and in HFD-fed KIKO female mice, in part by reducing energy intake and feeding efficiency. EB reduced fasting glucose levels in KIKO mice fed both diets but augmented glucose tolerance only in HFD-fed KIKO female mice. Plasma insulin and interleukin 6 were elevated in KIKO and KO female mice compared with LFD-fed WT female mice. Expression of arcuate neuropeptide and receptor genes and liver fatty acid biosynthesis genes was altered by HFD and by EB through ERE-dependent and -independent mechanisms. Therefore, ERE-independent signaling mechanisms in both the brain and peripheral organs mediate, in part, the effects of E2 during DIO. Copyright © 2017 by the Endocrine Society.

  15. Protective effect of prion protein via the N-terminal region in mediating a protective effect on paraquat-induced oxidative injury in neuronal cells.

    PubMed

    Dupiereux, Ingrid; Falisse-Poirrier, Nandini; Zorzi, Willy; Watt, Nicole T; Thellin, Olivier; Zorzi, Danièle; Pierard, Olivier; Hooper, Nigel M; Heinen, Ernst; Elmoualij, Benaïssa

    2008-02-15

    Transmissible spongiform encephalopathies are a group of neurodegenerative disorders caused by a posttranslational, conformational change in the cellular isoform of the prion protein (PrP(C)) into an infectious, disease-associated form (PrP(Sc)). Increasing evidence supports a role for PrP(C) in the cellular response to oxidative stress. We investigated the effect of oxidative stress mediated by paraquat exposure on SH-SY5Y neuroblastoma cells. A loss of mitochondrial membrane potential and subsequent reduction in ATP production were demonstrated in untransfected SH-SY5Y cells, an effect that was ameliorated by the expression of PrP(C). Cells expressing either PrP-DeltaOct, which lacks the octapeptide repeats, or PrP-DA, in which the N-terminus is tethered to the membrane, showed increased sensitivity to paraquat compared with cells expressing wild-type PrP(C) as shown by reduced viability, loss of their membrane integrity, and reduced mitochondrial bioenergetic measurements. Exposure of prion-infected mouse SMB15S cells to paraquat resulted in a reduction in viability to levels similar to those seen in the untransfected SH-SY5Y cells. However, "curing" the cells with pentosan sulfate restored the viability to the level observed in the SH-SY5Y cells expressing PrP(C). These data would indicate that the molecular mechanism promoting cellular resistance to oxidative stress had been compromised in the infected SMB15S cells, which could be reinstated upon curing. Our study supports the hypothesis that PrP(C) expression protects cells against paraquat-induced oxidative injury, demonstrates the significance of the N-terminal region of the protein in mediating this protective effect, and also shows that the biochemical consequences of prion infection may be reversed with therapeutic intervention. (c) 2007 Wiley-Liss, Inc.

  16. Distinct Mechanisms Underlying Resveratrol-Mediated Protection from Types of Cellular Stress in C6 Glioma Cells.

    PubMed

    Means, John C; Gerdes, Bryan C; Koulen, Peter

    2017-07-14

    The polyphenolic phytostilbene, trans-resveratrol, is found in high amounts in several types and tissues of plants, including grapes, and has been proposed to have beneficial effects in the central nervous system due to its activity as an antioxidant. The objective of the present study was to identify the mechanisms underlying the protective effects of resveratrol under conditions of oxidative stress or DNA damage, induced by the extracellularly applied oxidant, tert-butyl hydrogen peroxide, or UV-irradiation, respectively. In C6 glioma cells, a model system for glial cell biology and pharmacology, resveratrol was protective against both types of insult. Prevention of tau protein cleavage and of the formation of neurofibrillary tangles were identified as mechanisms of action of resveratrol-mediated protection in both paradigms of cellular damage. However, depending on the type of insult, resveratrol exerted its protective activity differentially: under conditions of chemically induced oxidative stress, inhibition of caspase activity, while with DNA damage, resveratrol regulated tau phosphorylation at Ser(422). Results advance our understanding of resveratrol's complex impact on cellular signaling pathway and contribute to the notion of resveratrol's role as a pleiotropic therapeutic agent.

  17. Protective effects of arachidonic acid against palmitic acid-mediated lipotoxicity in HIT-T15 cells.

    PubMed

    Cho, Young Sik; Kim, Chi Hyun; Kim, Ki Young; Cheon, Hyae Gyeong

    2012-05-01

    Saturated fatty acids have been considered major contributing factors in type 2 diabetes, whereas unsaturated fatty acids have beneficial effects for preventing the development of diabetes. However, the effects of polyunsaturated fatty acids in pancreatic β cells have not been reported. Here, we examined the effects of arachidonic acid (AA) on palmitic acid (PA)-mediated lipotoxicity in clonal HIT-T15 pancreatic β cells. AA prevented the PA-induced lipotoxicity as indicated by cell viability, DNA fragmentation and mitochondrial membrane potential, whereas eicosatetraynoic acid (ETYA), a non-metabolizable AA, had little effect on PA-induced lipotoxicity. In parallel with its protective effects against PA-induced lipotoxicity, AA restored impaired insulin expression and secretion induced by PA. AA but not ETYA increased intracellular triglyceride (TG) in the presence of PA compared with PA alone, and xanthohumol, a diacylglycerol acyltransferase (DGAT) inhibitor, reversed AA-induced protection from PA. Taken together, our results suggest that AA protects against PA-induced lipotoxicity in clonal HIT-T15 pancreatic β cells, and the protective effects may be associated with TG accumulation, possibly through sequestration of lipotoxic PA into TG.

  18. Latent infection of myeloid progenitors by human cytomegalovirus protects cells from FAS-mediated apoptosis through the cellular IL-10/PEA-15 pathway.

    PubMed

    Poole, Emma; Lau, Jonathan C H; Sinclair, John

    2015-08-01

    Latent infection of primary CD34(+) progenitor cells by human cytomegalovirus (HCMV) results in their increased survival in the face of pro-apoptotic signals. For instance, we have shown previously that primary myeloid cells are refractory to FAS-mediated killing and that cellular IL-10 (cIL-10) is an important survival factor for this effect. However, how cIL-10 mediates this protection is unclear. Here, we have shown that cIL-10 signalling leading to upregulation of the cellular factor PEA-15 mediates latency-associated protection of CD34(+) progenitor cells from the extrinsic death pathway.

  19. Ankyrin-mediated self-protection during cell invasion by the bacterial predator Bdellovibrio bacteriovorus

    PubMed Central

    Lambert, Carey; Cadby, Ian T.; Till, Rob; Bui, Nhat Khai; Lerner, Thomas R.; Hughes, William S.; Lee, David J.; Alderwick, Luke J.; Vollmer, Waldemar; Sockett, Elizabeth R.; Lovering, Andrew L.

    2015-01-01

    Predatory Bdellovibrio bacteriovorus are natural antimicrobial organisms, killing other bacteria by whole-cell invasion. Self-protection against prey-metabolizing enzymes is important for the evolution of predation. Initial prey entry involves the predator's peptidoglycan DD-endopeptidases, which decrosslink cell walls and prevent wasteful entry by a second predator. Here we identify and characterize a self-protection protein from B. bacteriovorus, Bd3460, which displays an ankyrin-based fold common to intracellular pathogens of eukaryotes. Co-crystal structures reveal Bd3460 complexation of dual targets, binding a conserved epitope of each of the Bd3459 and Bd0816 endopeptidases. Complexation inhibits endopeptidase activity and cell wall decrosslinking in vitro. Self-protection is vital — ΔBd3460 Bdellovibrio deleteriously decrosslink self-peptidoglycan upon invasion, adopt a round morphology, and lose predatory capacity and cellular integrity. Our analysis provides the first mechanistic examination of self-protection in Bdellovibrio, documents protection-multiplicity for products of two different genomic loci, and reveals an important evolutionary adaptation to an invasive predatory bacterial lifestyle. PMID:26626559

  20. Rap1 mediates protective effects of iloprost against ventilator-induced lung injury

    PubMed Central

    Birukova, Anna A.; Fu, Panfeng; Xing, Junjie

    2009-01-01

    Prostaglandin I2 (PGI2) has been shown to attenuate vascular constriction, hyperpermeability, inflammation, and acute lung injury. However, molecular mechanisms of PGI2 protective effects on pulmonary endothelial cells (EC) are not well understood. We tested a role of cAMP-activated Epac-Rap1 pathway in the barrier protective effects of PGI2 analog iloprost in the murine model of ventilator-induced lung injury. Mice were treated with iloprost (2 μg/kg) after onset of high tidal volume ventilation (30 ml/kg, 4 h). Bronchoalveolar lavage, histological analysis, and measurements of Evans blue accumulation were performed. In vitro, microvascular EC barrier function was assessed by morphological analysis of agonist-induced gap formation and monitoring of Rho pathway activation and EC permeability. Iloprost reduced bronchoalveolar lavage protein content, neutrophil accumulation, capillary filtration coefficient, and Evans blue albumin extravasation caused by high tidal volume ventilation. Small-interfering RNA-based Rap1 knockdown inhibited protective effects of iloprost. In vitro, iloprost increased barrier properties of lung microvascular endothelium and alleviated thrombin-induced EC barrier disruption. In line with in vivo results, Rap1 depletion attenuated protective effects of iloprost in the thrombin model of EC permeability. These data describe for the first time protective effects for Rap1-dependent signaling against ventilator-induced lung injury and pulmonary endothelial barrier dysfunction. PMID:19850733

  1. Ankyrin-mediated self-protection during cell invasion by the bacterial predator Bdellovibrio bacteriovorus.

    PubMed

    Lambert, Carey; Cadby, Ian T; Till, Rob; Bui, Nhat Khai; Lerner, Thomas R; Hughes, William S; Lee, David J; Alderwick, Luke J; Vollmer, Waldemar; Sockett, R Elizabeth; Sockett, Elizabeth R; Lovering, Andrew L

    2015-12-02

    Predatory Bdellovibrio bacteriovorus are natural antimicrobial organisms, killing other bacteria by whole-cell invasion. Self-protection against prey-metabolizing enzymes is important for the evolution of predation. Initial prey entry involves the predator's peptidoglycan DD-endopeptidases, which decrosslink cell walls and prevent wasteful entry by a second predator. Here we identify and characterize a self-protection protein from B. bacteriovorus, Bd3460, which displays an ankyrin-based fold common to intracellular pathogens of eukaryotes. Co-crystal structures reveal Bd3460 complexation of dual targets, binding a conserved epitope of each of the Bd3459 and Bd0816 endopeptidases. Complexation inhibits endopeptidase activity and cell wall decrosslinking in vitro. Self-protection is vital - ΔBd3460 Bdellovibrio deleteriously decrosslink self-peptidoglycan upon invasion, adopt a round morphology, and lose predatory capacity and cellular integrity. Our analysis provides the first mechanistic examination of self-protection in Bdellovibrio, documents protection-multiplicity for products of two different genomic loci, and reveals an important evolutionary adaptation to an invasive predatory bacterial lifestyle.

  2. Reactive oxygen species as mediators of cardiac injury and protection: the relevance to anesthesia practice.

    PubMed

    Kevin, Leo G; Novalija, Enis; Stowe, David F

    2005-11-01

    Reactive oxygen species (ROS) are central to cardiac ischemic and reperfusion injury. They contribute to myocardial stunning, infarction and apoptosis, and possibly to the genesis of arrhythmias. Multiple laboratory studies and clinical trials have evaluated the use of scavengers of ROS to protect the heart from the effects of ischemia and reperfusion. Generally, studies in animal models have shown such effects. Clinical trials have also shown protective effects of scavengers, but whether this protection confers meaningful clinical benefits is uncertain. Several IV anesthetic drugs act as ROS scavengers. In contrast, volatile anesthetics have recently been demonstrated to generate ROS in the heart, most likely because of inhibitory effects on cardiac mitochondria. ROS are involved in the signaling cascade for cardioprotection induced by brief exposure to a volatile anesthetic (termed "anesthetic preconditioning"). ROS, therefore, although injurious in large quantities, can have a paradoxical protective effect within the heart. In this review we provide background information on ROS formation and elimination relevant to anesthetic and adjuvant drugs with particular reference to the heart. The sources of ROS, the means by which they induce cardiac injury or activate protective signaling pathways, the results of clinical studies evaluating ROS scavengers, and the effects of anesthetic drugs on ROS are each discussed.

  3. Characterization of the functional role of nucleotides within the URE2 IRES element and the requirements for eIF2A-mediated repression.

    PubMed

    Reineke, Lucas C; Merrick, William C

    2009-12-01

    Cap-independent initiation of translation is thought to promote protein synthesis on some mRNAs during times when cap-dependent initiation is down-regulated. However, the mechanism of cap-independent initiation is poorly understood. We have previously reported the secondary structure within the yeast minimal URE2 IRES element. In this study, we sought to investigate the mechanism of internal initiation in yeast by assessing the functional role of nucleotides within the minimal URE2 IRES element, and delineating the cis-sequences that modulate levels of internal initiation using a monocistronic reporter vector. Furthermore, we compared the eIF2A sensitivity of the URE2 IRES element with some of the invasive growth IRES elements using DeltaeIF2A yeast. We found that the stability of the stem-loop structure within the minimal URE2 IRES element is not a critical determinant of optimal IRES activity, and the downstream sequences that modulate URE2 IRES-mediated translation can be defined to discrete regions within the URE2 coding region. Repression of internal initiation on the URE2 minimal IRES element by eIF2A is not dependent on the stability of the secondary structure within the URE2 IRES element. Our data also indicate that eIF2A-mediated repression is not specific to the URE2 IRES element, as both the GIC1 and PAB1 IRES elements are repressed by eIF2A. These data provide valuable insights into the mRNA requirements for internal initiation in yeast, and insights into the mechanism of eIF2A-mediated suppression.

  4. AAV-mediated in vivo functional selection of tissue-protective factors against ischaemia

    PubMed Central

    Ruozi, Giulia; Bortolotti, Francesca; Falcione, Antonella; Dal Ferro, Matteo; Ukovich, Laura; Macedo, Antero; Zentilin, Lorena; Filigheddu, Nicoletta; Cappellari, Gianluca Gortan; Baldini, Giovanna; Zweyer, Marina; Barazzoni, Rocco; Graziani, Andrea; Zacchigna, Serena; Giacca, Mauro

    2015-01-01

    Functional screening of expression libraries in vivo would offer the possibility of identifying novel biotherapeutics without a priori knowledge of their biochemical function. Here we describe a procedure for the functional selection of tissue-protective factors based on the in vivo delivery of arrayed cDNA libraries from the mouse secretome using adeno-associated virus (AAV) vectors. Application of this technique, which we call FunSel, in the context of acute ischaemia, revealed that the peptide ghrelin protects skeletal muscle and heart from ischaemic damage. When delivered to the heart using an AAV9 vector, ghrelin markedly reduces infarct size and preserves cardiac function over time. This protective activity associates with the capacity of ghrelin to sustain autophagy and remove dysfunctional mitochondria after myocardial infarction. Our findings describe an innovative tool to identify biological therapeutics and reveal a novel role of ghrelin as an inducer of myoprotective autophagy. PMID:26066847

  5. Heme oxygenase-1 mediated memorial and revivable protective effect of ischemic preconditioning on brain injury.

    PubMed

    Le, Li-Li; Li, Xue-Yi; Meng, Dan; Liang, Qiu-Jun; Wang, Xin-Hong; Li, Ning; Quan, Jing; Xiang, Meng; Jiang, Mei; Sun, Jian; Chen, Si-Feng

    2013-12-01

    Ischemic preconditioning (IPC) has short-term benefits for stroke patients. However, if IPC protective effect is memorial and the role of the intracellular protective protein heme oxygenase-1 (HO-1) is not known. Ischemic preconditioning and the corresponding sham control were achieved by blocking the blood flow of the left internal carotid artery for 20 min and 2 second, respectively, in rats. Both IPC and sham-operated animals were divided into three groups and treated with PBS, the HO-1 inducer hemin, and the HO-1 inhibitor Znpp. Three weeks after IPC, brain ischemia-reperfusion injury was achieved by left middle cerebral artery obstruction for 45 min followed by 24-h reperfusion. 2,3,5-triphenyltetrazolium chloride staining and neurological dysfunction scoring showed IPC significantly reduced brain infarct area and improved neurological function occurred 3 weeks after IPC. Hemin treatment promoted whereas ZnPP blocked the benefits of IPC. Immunohistochemical analysis and Western blotting showed that the expression of HO-1 was higher in the border zone than in the necrotic core zone. The memorial IPC protection is independent of adenosine receptor A1R and A2aR expressions. We found for the first time that the protective effect of IPC can be remembered to protect brain injury occurred after acute response disappear. The results indicate that interventional treatment can achieve protective effect for future cerebral injury not only through interventional treatment itself but also through the memorial and revivable IPC, eliminating the concern that temporary ischemia caused by interventional treatment may leave harmful effect in the brain. © 2013 John Wiley & Sons Ltd.

  6. C-Phycocyanin Confers Protection against Oxalate-Mediated Oxidative Stress and Mitochondrial Dysfunctions in MDCK Cells

    PubMed Central

    Farooq, Shukkur M.; Boppana, Nithin B.; Asokan, Devarajan; Sekaran, Shamala D.; Shankar, Esaki M.; Li, Chunying; Gopal, Kaliappan; Bakar, Sazaly A.; Karthik, Harve S.; Ebrahim, Abdul S.

    2014-01-01

    Oxalate toxicity is mediated through generation of reactive oxygen species (ROS) via a process that is partly dependent on mitochondrial dysfunction. Here, we investigated whether C-phycocyanin (CP) could protect against oxidative stress-mediated intracellular damage triggered by oxalate in MDCK cells. DCFDA, a fluorescence-based probe and hexanoyl-lysine adduct (HEL), an oxidative stress marker were used to investigate the effect of CP on oxalate-induced ROS production and membrane lipid peroxidation (LPO). The role of CP against oxalate-induced oxidative stress was studied by the evaluation of mitochondrial membrane potential by JC1 fluorescein staining, quantification of ATP synthesis and stress-induced MAP kinases (JNK/SAPK and ERK1/2). Our results revealed that oxalate-induced cells show markedly increased ROS levels and HEL protein expression that were significantly decreased following pre-treatment with CP. Further, JC1 staining showed that CP pre-treatment conferred significant protection from mitochondrial membrane permeability and increased ATP production in CP-treated cells than oxalate-alone-treated cells. In addition, CP treated cells significantly decreased the expression of phosphorylated JNK/SAPK and ERK1/2 as compared to oxalate-alone-treated cells. We concluded that CP could be used as a potential free radical-scavenging therapeutic strategy against oxidative stress-associated diseases including urolithiasis. PMID:24691130

  7. Protective effect of HDL on NADPH oxidase-derived super oxide anion mediates hypoxia-induced cardiomyocyte apoptosis.

    PubMed

    Wen, Su-Ying; Tamilselvi, Shanmugam; Shen, Chia-Yao; Day, Cecilia Hsuan; Chun, Li-Chin; Cheng, Li-Yi; Ou, Hsiu-Chung; Chen, Ray-Jade; Viswanadha, Vijaya Padma; Kuo, Wei-Wen; Huang, Chih-Yang

    2017-01-01

    Cardiovascular diseases are the leading cause of death of death in Taiwan. Atherosclerosis can lead to serious problems, including heart attack, stroke, or even death. Coronary heart disease (CHD) occurs when plaque builds up in the coronary arteries to cause the ischemic heart disease which will enhance myocardial remodeling and also induce myocardial hypoxia. High density lipoprotein (HDL) has been proposed to have cardio-protective effects. Under hypoxic conditions (1%O2 for 24hr), in H9c2 cells, reactive oxygen species (ROS) is induced which leads to cardiomyocyte apoptosis and cardiac dysfunction. Therefore, the present study described the protective effect of HDL on hypoxia-induced cardiomyocyte damage. We investigated the NADPH oxidase-produced ROS-related signaling pathways and apoptosis in cardiomyocytes under hypoxia conditions. Results showed that the ROS mediated cardiac damage might occur via AT1 and PKC activation. Furthermore, hypoxia downregulated the survival protein (p-AKTser473) and anti-apoptotic protein (BCL2), whereas pro-apoptotic protein, Bax and caspase 3 were upregulated. These detrimental effects by ROS and apoptosis were prevented by HDL pretreatment. Our findings revealed the underlying molecular mechanism by which HDL suppresses the hypoxia-induced cardiomyocyte dysfunction. Further, we elucidated the role of HDL on preventing hypoxia induced cardiomyocyte apoptosis is mediated through the inhibition of NADPH oxidase-derived ROS.

  8. C-phycocyanin confers protection against oxalate-mediated oxidative stress and mitochondrial dysfunctions in MDCK cells.

    PubMed

    Farooq, Shukkur M; Boppana, Nithin B; Devarajan, Asokan; Asokan, Devarajan; Sekaran, Shamala D; Shankar, Esaki M; Li, Chunying; Gopal, Kaliappan; Bakar, Sazaly A; Karthik, Harve S; Ebrahim, Abdul S

    2014-01-01

    Oxalate toxicity is mediated through generation of reactive oxygen species (ROS) via a process that is partly dependent on mitochondrial dysfunction. Here, we investigated whether C-phycocyanin (CP) could protect against oxidative stress-mediated intracellular damage triggered by oxalate in MDCK cells. DCFDA, a fluorescence-based probe and hexanoyl-lysine adduct (HEL), an oxidative stress marker were used to investigate the effect of CP on oxalate-induced ROS production and membrane lipid peroxidation (LPO). The role of CP against oxalate-induced oxidative stress was studied by the evaluation of mitochondrial membrane potential by JC1 fluorescein staining, quantification of ATP synthesis and stress-induced MAP kinases (JNK/SAPK and ERK1/2). Our results revealed that oxalate-induced cells show markedly increased ROS levels and HEL protein expression that were significantly decreased following pre-treatment with CP. Further, JC1 staining showed that CP pre-treatment conferred significant protection from mitochondrial membrane permeability and increased ATP production in CP-treated cells than oxalate-alone-treated cells. In addition, CP treated cells significantly decreased the expression of phosphorylated JNK/SAPK and ERK1/2 as compared to oxalate-alone-treated cells. We concluded that CP could be used as a potential free radical-scavenging therapeutic strategy against oxidative stress-associated diseases including urolithiasis.

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

    PubMed Central

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

    2017-01-01

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

  10. Folic acid protects against arsenic-mediated embryo toxicity by up-regulating the expression of Dvr1

    PubMed Central

    Ma, Yan; Zhang, Chen; Gao, Xiao-Bo; Luo, Hai-Yan; Chen, Yang; Li, Hui-hua; Ma, Xu; Lu, Cai-Ling

    2015-01-01

    As a nutritional factor, folic acid can prevent cardiac and neural defects during embryo development. Our previous study showed that arsenic impairs embryo development by down-regulating Dvr1/GDF1 expression in zebrafish. Here, we investigated whether folic acid could protect against arsenic-mediated embryo toxicity. We found that folic acid supplementation increases hatching and survival rates, decreases malformation rate and ameliorates abnormal cardiac and neural development of zebrafish embryos exposed to arsenite. Both real-time PCR analysis and whole in-mount hybridization showed that folic acid significantly rescued the decrease in Dvr1 expression caused by arsenite. Subsequently, our data demonstrated that arsenite significantly decreased cell viability and GDF1 mRNA and protein levels in HEK293ET cells, while folic acid reversed these effects. Folic acid attenuated the increase in subcellular reactive oxygen species (ROS) levels and oxidative adaptor p66Shc protein expression in parallel with the changes in GDF1 expression and cell viability. P66Shc knockdown significantly inhibited the production of ROS and the down-regulation of GDF1 induced by arsenite. Our data demonstrated that folic acid supplementation protected against arsenic-mediated embryo toxicity by up-regulating the expression of Dvr1/GDF1, and folic acid enhanced the expression of GDF1 by decreasing p66Shc expression and subcellular ROS levels. PMID:26537450

  11. Blocking by anti-idiotypic antibodies of monoclonal antibody-mediated protection against lethal Semliki Forest virus in mice.

    PubMed

    Oosterlaken, T A; Harmsen, M; Kraaijeveld, C A; Snippe, H

    1990-02-01

    Semliki Forest virus-(SEV) neutralizing monoclonal antibodies (MoAbs), produced after fusion of spleen cells from BALB/c mice and myeloma cell line P3-X63-AG8. 653 or SP2/0, were used for anti-idiotypic immunization of female BALB/c mice. Two intracutaneous immunizations (2 x 40 micrograms per animal), 3 weeks apart, with keyhole limpet haemocyanin-conjugated MoAbs mixed with the saponin Quil A were sufficient to induce high levels of anti-idiotypic antibodies in the circulation of these mice with the capacity to block specifically in vitro MoAb-mediated virus neutralization. Anti-idiotypic antibodies against SFV-neutralizing MoAbs, either passively transferred or actively acquired by immunization, are also able to abrogate (specifically) passive immunity, mediated by critical protective doses of MoAb, in mice against infection with a lethal strain of SFV. Furthermore we confirmed by intervention with anti-idiotypic serum in vivo that an SFV-neutralizing MoAb exerts its greatest protective effect during the first 2 days of infection.

  12. Potential Protective Effects of Ursolic Acid against Gamma Irradiation-Induced Damage Are Mediated through the Modulation of Diverse Inflammatory Mediators

    PubMed Central

    Wang, Hong; Sim, Meng-Kwoon; Loke, Weng Keong; Chinnathambi, Arunachalam; Alharbi, Sulaiman Ali; Tang, Feng Ru; Sethi, Gautam

    2017-01-01

    This study was aimed to evaluate the possible protective effects of ursolic acid (UA) against gamma radiation induced damage both in vitro as well as in vivo. It was observed that the exposure to gamma radiation dose- and time-dependently caused a significant decrease in the cell viability, while the treatment of UA attenuated this cytotoxicity. The production of free radicals including reactive oxygen species (ROS) and NO increased significantly post-irradiation and further induced lipid peroxidation and oxidative DNA damage in cells. These deleterious effects could also be effectively blocked by UA treatment. In addition, UA also reversed gamma irradiation induced inflammatory responses, as indicated by the decreased production of TNF-α, IL-6, and IL-1β. NF-κB signaling pathway has been reported to be a key mediator involved in gamma radiation-induced cellular damage. Our results further demonstrated that gamma radiation dose- and time-dependently enhanced NF-κB DNA binding activity, which was significantly attenuated upon UA treatment. The post-irradiation increase in the expression of both phospho-p65, and phospho-IκBα was also blocked by UA. Moreover, the treatment of UA was found to significantly prolong overall survival in mice exposed to whole body gamma irradiation, and reduce the excessive inflammatory responses. Given its radioprotective efficacy as described here, UA as an antioxidant and NF-κB pathway blocker, may function as an important pharmacological agent in protecting against gamma irradiation-induced injury. PMID:28670276

  13. A Novel Pregnane X Receptor-mediated and Sterol Regulatory Element-binding Protein-independent Lipogenic Pathway*

    PubMed Central

    Zhou, Jie; Zhai, Yonggong; Mu, Ying; Gong, Haibiao; Uppal, Hirdesh; Toma, David; Ren, Songrong; Evans, Ronald M.; Xie, Wen

    2014-01-01

    The pregnane X receptor (PXR) was isolated as a xenosensor regulating xenobiotic responses. In this study, we show that PXR plays an endobiotic role by impacting lipid homeostasis. Expression of an activated PXR in the livers of transgenic mice resulted in an increased hepatic deposit of triglycerides. This PXR-mediated lipid accumulation was independent of the activation of the lipogenic transcriptional factor SREBP-1c (sterol regulatory element-binding protein 1c) and its primary lipogenic target enzymes, including fatty-acid synthase (FAS) and acetyl-CoA carboxylase 1 (ACC-1). Instead, the lipid accumulation in transgenic mice was associated with an increased expression of the free fatty acid transporter CD36 and several accessory lipogenic enzymes, such as stearoyl-CoA desaturase-1 (SCD-1) and long chain free fatty acid elongase. Studies using transgenic and knock-out mice showed that PXR is both necessary and sufficient for Cd36 activation. Promoter analyses revealed a DR-3-type of PXR-response element in the mouse Cd36 promoter, establishing Cd36 as a direct transcriptional target of PXR. The hepatic lipid accumulation and Cd36 induction were also seen in the hPXR “humanized” mice treated with the hPXR agonist rifampicin. The activation of PXR was also associated with an inhibition of pro-β-oxidative genes, such as peroxisome proliferator-activated receptor α (PPARα) and thiolase, and an up-regulation of PPARγ, a positive regulator of CD36. The cross-regulation of CD36 by PXR and PPARγ suggests that this fatty acid transporter may function as a common target of orphan nuclear receptors in their regulation of lipid homeostasis. PMID:16556603

  14. FABP4-Cre mediated expression of constitutively active ChREBP protects against obesity

    USDA-ARS?s Scientific Manuscript database

    Carbohydrate response element binding protein (ChREBP) regulates cellular glucose and lipid homeostasis. Although ChREBP is highly expressed in many key metabolic tissues, the role of ChREBP in most of those tissues and consequent effects on whole-body glucose and lipid metabolism are not well under...

  15. Effect of Positive Psychology Elements on Job Pride and Honor with an Emphasis on Mediating Role of Communication among Faculty Members of Shiraz University of Medical Sciences

    ERIC Educational Resources Information Center

    Hosein Kamani, Seyed Mohammad

    2017-01-01

    Job pride and honor is affected by various causes. Elements of positive psychology can be pointed out as one of them that in recent years has played an important role in organizational development. Hence, this study is to provide a prediction model about the impact of hope and resilience on job pride and honor with an emphasis on mediator role of…

  16. SNMIB/Apollo protects leading-strand telomeres against NHEJ-mediated repair

    PubMed Central

    Lam, Yung C; Akhter, Shamima; Gu, Peili; Ye, Jing; Poulet, Anaïs; Giraud-Panis, Marie-Josèphe; Bailey, Susan M; Gilson, Eric; Legerski, Randy J; Chang, Sandy

    2010-01-01

    Progressive telomere attrition or deficiency of the protective shelterin complex elicits a DNA damage response as a result of a cell's inability to distinguish dysfunctional telomeric ends from DNA double-strand breaks. SNMIB/Apollo is a shelterin-associated protein and a member of the SMN1/PSO2 nuclease family that localizes to telomeres through its interaction with TRF2. Here, we generated SNMIB/Apollo knockout mouse embryo fibroblasts (MEFs) to probe the function of SNMIB/Apollo at mammalian telomeres. SNMIB/Apollo null MEFs exhibit an increased incidence of G2 chromatid-type fusions involving telomeres created by leading-strand DNA synthesis, reflective of a failure to protect these telomeres after DNA replication. Mutations within SNMIB/Apollo's conserved nuclease domain failed to suppress this phenotype, suggesting that its nuclease activity is required to protect leading-strand telomeres. SNMIB/Apollo−/−ATM−/− MEFs display robust telomere fusions when Trf2 is depleted, indicating that ATM is dispensable for repair of uncapped telomeres in this setting. Our data implicate the 5′–3′ exonuclease function of SNM1B/Apollo in the generation of 3′ single-stranded overhangs at newly replicated leading-strand telomeres to protect them from engaging the non-homologous end-joining pathway. PMID:20551906

  17. Mechanism of T-cell mediated protection in newborn mice against a Chlamydia infection.

    PubMed

    Pal, Sukumar; de la Maza, Luis M

    2013-01-01

    To determine the immune components needed for protection of newborn mice against Chlamydia muridarum, animals born to Chlamydia-immunized and to sham-immunized dams were infected intranasally with C. muridarum at 2 post-natal days. T-cells isolated from immunized or sham-immunized adult mice were adoptively transferred to newborn mice at the time of infection. Also, to establish what cytokines are involved in protection, IFN-γ, TNF-α, IL-10, and IL-12 were passively transferred to newborn mice. To assess the Chlamydia burden in the lungs mice were euthanized at 12 post-natal days. When T-cells from immunized adult mice were transferred, mice born to and fed by immunized dams were significantly protected as evidenced by the reduced number of Chlamydia isolated from the lungs compared to mice born to and fed by sham-immunized dams. Transfer of IFN-γ and TNF-α also significantly reduced the number of Chlamydia in the lungs of mice born to immunized dams. Transfer of IL-10 or IL-12 did not result in a significant reduction of Chlamydia. In vitro T-cell proliferation data suggest that neonatal antigen presenting cells can present Chlamydia antigens to adult T-cells. In conclusion, maternal antibodies and Chlamydia specific T-cells or Th1 cytokines are required for protection of neonates against this pathogen.

  18. Heat shock protein 75 (TRAP1) antagonizes reactive oxygen species generation and protects cells from granzyme M-mediated apoptosis.

    PubMed

    Hua, Guoqiang; Zhang, Qixiang; Fan, Zusen

    2007-07-13

    Natural killer (NK) cells play an important role in innate immunity against virally infected or transformed cells as the first defense line. Granzyme M (GzmM) is an orphan granzyme that is constitutively highly expressed in NK cells and is consistent with NK cell-mediated cytolysis. We recently demonstrated that GzmM induces caspase-dependent apoptosis with DNA fragmentation through direct cleavage of inhibitor of caspase-activated DNase (ICAD). However, the molecular mechanisms for GzmM-induced apoptosis are unclear. We found GzmM causes mitochondrial swelling and loss of mitochondrial transmembrane potential. Moreover, GzmM initiates reactive oxygen species (ROS) generation and cytochrome c release. Heat shock protein 75 (HSP75, also known as TRAP1) acts as an antagonist of ROS and protects cells from GzmM-mediated apoptosis. GzmM cleaves TRAP1 and abolishes its antagonistic function to ROS, resulting in ROS accumulation. Silencing TRAP1 through RNA interference increases ROS accumulation, whereas TRAP1 overexpression attenuates ROS production. ROS accumulation is in accordance with the release of cytochrome c from mitochondria and enhances GzmM-mediated apoptosis.

  19. Renal Handling of Circulating and Renal-Synthesized Hepcidin and Its Protective Effects against Hemoglobin-Mediated Kidney Injury.

    PubMed

    van Swelm, Rachel P L; Wetzels, Jack F M; Verweij, Vivienne G M; Laarakkers, Coby M M; Pertijs, Jeanne C L M; van der Wijst, Jenny; Thévenod, Frank; Masereeuw, Rosalinde; Swinkels, Dorine W

    2016-09-01

    Urinary hepcidin may have protective effects against AKI. However, renal handling and the potential protective mechanisms of hepcidin are not fully understood. By measuring hepcidin levels in plasma and urine using mass spectrometry and the kidney using immunohistochemistry after intraperitoneal administration of human hepcidin-25 (hhep25) in C57Bl/6N mice, we showed that circulating hepcidin is filtered by the glomerulus and degraded to smaller isoforms detected in urine but not plasma. Moreover, hepcidin colocalized with the endocytic receptor megalin in proximal tubules, and compared with wild-type mice, megalin-deficient mice showed higher urinary excretion of injected hhep25 and no hepcidin staining in proximal tubules that lack megalin. This indicates that hepcidin is reaborbed in the proximal tubules by megalin dependent endocytosis. Administration of hhep25 concomitant with or 4 hours after a single intravenous dose of hemoglobin abolished hemoglobin-induced upregulation of urinary kidney injury markers (NGAL and KIM-1) and renal Interleukin-6 and Ngal mRNA observed 24 hours after administration but did not affect renal ferroportin expression at this point. Notably, coadministration of hhep25 and hemoglobin but not administration of either alone greatly increased renal mRNA expression of hepcidin-encoding Hamp1 and hepcidin staining in distal tubules. These findings suggest a role for locally synthesized hepcidin in renal protection. Our observations did not support a role for ferroportin in hhep25-mediated protection against hemoglobin-induced early injury, but other mechanisms of cellular iron handling may be involved. In conclusion, our data suggest that both systemically delivered and locally produced hepcidin protect against hemoglobin-induced AKI.

  20. Protected Nuclear Fuel Element

    DOEpatents

    Kittel, J. H.; Schumar, J. F.

    1962-12-01

    A stainless steel-clad actinide metal fuel rod for use in fast reactors is reported. In order to prevert cladding failures due to alloy formation between the actinide metal and the stainless steel, a mesh-like sleeve of expanded metal is interposed between them, the sleeve metal being of niobium, tantalum, molybdenum, tungsten, zirconium, or vanadium. Liquid alkali metal is added as a heat transfer agent. (AEC)

  1. Vaccination with TAT-antigen fusion protein induces protective, CD8(+) T cell-mediated immunity against Leishmania major.

    PubMed

    Kronenberg, Katharina; Brosch, Sven; Butsch, Florian; Tada, Yayoi; Shibagaki, Naotaka; Udey, Mark C; von Stebut, Esther

    2010-11-01

    In murine leishmaniasis, healing is mediated by IFN-γ-producing CD4(+) and CD8(+) T cells. Thus, an efficacious vaccine should induce Th1 and Tc1 cells. Dendritic cells (DCs) pulsed with exogenous proteins primarily induce strong CD4-dependent immunity; induction of CD8 responses has proven to be difficult. We evaluated the immunogenicity of fusion proteins comprising the protein transduction domain of HIV-1 TAT and the Leishmania antigen LACK (Leishmania homolog of receptors for activated C kinase), as TAT-fusion proteins facilitate major histocompatibility complex class I-dependent antigen presentation. In vitro, TAT-LACK-pulsed DCs induced stronger proliferation of Leishmania-specific CD8(+) T cells compared with DCs incubated with LACK alone. Vaccination with TAT-LACK-pulsed DCs or fusion proteins plus adjuvant in vivo significantly improved disease outcome in Leishmania major-infected mice and was superior to vaccination with DCs treated with LACK alone. Vaccination with DC+TAT-LACK resulted in stronger proliferation of CD8(+) T cells when compared with immunization with DC+LACK. Upon depletion of CD4(+) or CD8(+) T cells, TAT-LACK-mediated protection was lost. TAT-LACK-pulsed IL-12p40-deficient DCs did not promote protection in vivo. In summary, these data show that TAT-fusion proteins are superior in activating Leishmania-specific Tc1 cells when compared with antigen alone and suggest that IL-12-dependent preferential induction of antigen-specific CD8(+) cells promotes significant protection against this important human pathogen.

  2. Apelin protects against liver X receptor-mediated steatosis through AMPK and PPARα in human and mouse hepatocytes.

    PubMed

    Huang, Jin; Kang, Saeromi; Park, Soo-Jin; Im, Dong-Soon

    2017-11-01

    Non-alcoholic fatty liver disease is the most commonly occurring chronic liver disease, and hepatic steatosis, a condition defined as extensive lipid accumulation in hepatocytes, is associated with liver dysfunction and metabolic diseases, such as, obesity and type II diabetes. Apelin is an adipokine that acts on a G protein-coupled receptor named APJ, and has been established to play pivotal roles in various physiological conditions. However, the function of apelin in hepatocytes has not been fully investigated. In order to assess the functional roles of apelin and APJ in hepatocytes, we used an in vitro model of liver X receptor (LXR)-mediated hepatocellular steatosis. In Hep3B human hepatoma cells, T0901317 (a specific LXR activator) induced lipid accumulation and this was inhibited by apelin. T0901317 also induced the expression of SREBP-1c, a key transcription factor for lipogenesis. Apelin not only inhibited SREBP-1c induction at the mRNA and protein levels but also induced lipolytic PPARα expression. Furthermore, these protective effects of apelin were inhibited by apelin F13A (a specific APJ antagonist). Furthermore, silencing of APJ by siRNA transfection also inhibited the actions of apelin. Specific inhibitors of cellular signaling components showed inhibition of lipid accumulation by apelin was mediated through Gi/o proteins, AMPK, and SREBP-1c suppression during the early stage and through AMPK, ERKs, and PPARα induction during the late stage. In addition, the protective effect of apelin was confirmed in mouse primary hepatocytes. Our observations suggest apelin-APJ signaling in hepatocytes functions to protect against lipid accumulation in liver through two signaling pathways, that is, via AMPK activation and PPARα induction. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Protection of protease-activated receptor 2 mediated vasodilatation against angiotensin II-induced vascular dysfunction in mice

    PubMed Central

    2011-01-01

    Background Under conditions of cardiovascular dysfunction, protease-activated receptor 2 (PAR2) agonists maintain vasodilatation activity, which has been attributed to increased cyclooxygenase-2, nitric oxide synthase and calcium-activated potassium channel (SK3.1) activities. Protease-activated receptor 2 agonist mediated vasodilatation is unknown under conditions of dysfunction caused by angiotensin II. The main purpose of our study was to determine whether PAR2-induced vasodilatation of resistance arteries was attenuated by prolonged angiotensin II treatment in mice. We compared the vasodilatation of resistance-type arteries (mesenteric) from angiotensin II-treated PAR2 wild-type mice (WT) induced by PAR2 agonist 2-furoyl-LIGRLO-amide (2fly) to the responses obtained in controls (saline treatment). We also investigated arterial vasodilatation in angiotensin II-treated PAR2 deficient (PAR2-/-) mice. Results 2fly-induced relaxations of untreated arteries from angiotensin II-treated WT were not different than saline-treated WT. Treatment of arteries with nitric oxide synthase inhibitor and SK3.1 inhibitor (L-NAME + TRAM-34) blocked 2fly in angiotensin II-treated WT. Protein and mRNA expression of cyclooxygenase-1 and -2 were increased, and cyclooxygenase activity increased the sensitivity of arteries to 2fly in only angiotensin II-treated WT. These protective vasodilatation mechanisms were selective for 2fly compared with acetylcholine- and nitroprusside-induced relaxations which were attenuated by angiotensin II; PAR2-/- were protected against this attenuation of nitroprusside. Conclusions PAR2-mediated vasodilatation of resistance type arteries is protected against the negative effects of angiotensin II-induced vascular dysfunction in mice. In conditions of endothelial dysfunction, angiotensin II induction of cyclooxygenases increases sensitivity to PAR2 agonist and the preserved vasodilatation mechanism involves activation of SK3.1. PMID:21955547

  4. Effect of 2-Hydroxyethyl Methacrylate on Antioxidant Responsive Element-Mediated Transcription: A Possible Indication of Its Cytotoxicity

    PubMed Central

    Orimoto, Ai; Suzuki, Takahiro; Ueno, Atsuko; Kawai, Tatsushi; Nakamura, Hiroshi; Kanamori, Takao

    2013-01-01

    Background The resin monomer 2-hydroxyethyl methacrylate (HEMA) is known to be more cytotoxic than methyl methacrylate (MMA). Using a luciferase reporter assay system, we previously showed that MMA activates the glutathione S-transferase alpha 1 gene (Gsta1) promoter through the anti-oxidant responsive element (ARE). However, it is not known whether HEMA induces ARE-mediated transcription. Methodology/Principal Findings We further developed the reporter system and studied the concentration-dependent effect of HEMA on ARE enhancer activity. The revised system employed HepG2 cells stably transfected with a destabilized luciferase reporter vector carrying 2 copies of the 41-bp ARE region of Gsta1. In this system, MMA increased ARE activity by 244-fold at 30 mM; HEMA augmented ARE activity at 3 mM more intensely than MMA (36-fold versus 11-fold) and was equipotent as MMA at 10 mM (56-fold activation); however, HEMA failed to increase ARE activity at 30 mM. In HepG2 cells, HEMA detectably lowered the cellular glutathione levels at 10 mM and cell viability at 30 mM, but MMA did not. Conclusions These results suggest that the low-concentration effect of HEMA on ARE activity reflects its cytotoxicity. Our reporter system used to examine ARE activity may be useful for evaluating cytotoxicities of resin monomers at concentrations lower than those for which cell viabilities are reduced. PMID:23516576

  5. Ultraconserved elements are associated with homeostatic control of splicing regulators by alternative splicing and nonsense-mediated decay

    PubMed Central

    Ni, Julie Z.; Grate, Leslie; Donohue, John Paul; Preston, Christine; Nobida, Naomi; O’Brien, Georgeann; Shiue, Lily; Clark, Tyson A.; Blume, John E.; Ares, Manuel

    2007-01-01

    Many alternative splicing events create RNAs with premature stop codons, suggesting that alternative splicing coupled with nonsense-mediated decay (AS-NMD) may regulate gene expression post-transcriptionally. We tested this idea in mice by blocking NMD and measuring changes in isoform representation using splicing-sensitive microarrays. We found a striking class of highly conserved stop codon-containing exons whose inclusion renders the transcript sensitive to NMD. A genomic search for additional examples identified >50 such exons in genes with a variety of functions. These exons are unusually frequent in genes that encode splicing activators and are unexpectedly enriched in the so-called “ultraconserved” elements in the mammalian lineage. Further analysis show that NMD of mRNAs for splicing activators such as SR proteins is triggered by splicing activation events, whereas NMD of the mRNAs for negatively acting hnRNP proteins is triggered by splicing repression, a polarity consistent with widespread homeostatic control of splicing regulator gene expression. We suggest that the extreme genomic conservation surrounding these regulatory splicing events within splicing factor genes demonstrates the evolutionary importance of maintaining tightly tuned homeostasis of RNA-binding protein levels in the vertebrate cell. PMID:17369403

  6. Enhanced Protection against Ebola Virus Mediated by an Improved Adenovirus-Based Vaccine

    PubMed Central

    Tran, Kaylie N.; Croyle, Maria A.; Strong, James E.; Feldmann, Heinz; Kobinger, Gary P.

    2009-01-01

    Background The Ebola virus is transmitted by direct contact with bodily fluids of infected individuals, eliciting death rates as high as 90% among infected humans. Currently, replication defective adenovirus-based Ebola vaccine is being studied in a phase I clinical trial. Another Ebola vaccine, based on an attenuated vesicular stomatitis virus has shown efficacy in post-exposure treatment of nonhuman primates to Ebola infection. In this report, we modified the common recombinant adenovirus serotype 5-based Ebola vaccine expressing the wild-type ZEBOV glycoprotein sequence from a CMV promoter (Ad-CMVZGP). The immune response elicited by this improved expression cassette vector (Ad-CAGoptZGP) and its ability to afford protection against lethal ZEBOV challenge in mice was compared to the standard Ad-CMVZGP vector. Methodology/Principal Findings Ad-CMVZGP was previously shown to protect mice, guinea pigs and nonhuman primates from an otherwise lethal challenge of Zaire ebolavirus. The antigenic expression cassette of this vector was improved through codon optimization, inclusion of a consensus Kozak sequence and reconfiguration of a CAG promoter (Ad-CAGoptZGP). Expression of GP from Ad-CAGoptZGP was substantially higher than from Ad-CMVZGP. Ad-CAGoptZGP significantly improved T and B cell responses at doses 10 to 100-fold lower than that needed with Ad-CMVZGP. Additionally, Ad-CAGoptZGP afforded full protections in mice against lethal challenge at a dose 100 times lower than the dose required for Ad-CMVZGP. Finally, Ad-CAGoptZGP induced full protection to mice when given 30 minutes post-challenge. Conclusions/Significance We describe an improved adenovirus-based Ebola vaccine capable of affording post-exposure protection against lethal challenge in mice. The molecular modifications of the new improved vaccine also translated in the induction of significantly enhanced immune responses and complete protection at a dose 100 times lower than with the previous generation

  7. Glycolytic enzymes localize to ribonucleoprotein granules in Drosophila germ cells, bind Tudor and protect from transposable elements.

    PubMed

    Gao, Ming; Thomson, Travis C; Creed, T Michael; Tu, Shikui; Loganathan, Sudan N; Jackson, Christina A; McCluskey, Patrick; Lin, Yanyan; Collier, Scott E; Weng, Zhiping; Lasko, Paul; Ohi, Melanie D; Arkov, Alexey L

    2015-03-01

    Germ cells give rise to all cell lineages in the next-generation and are responsible for the continuity of life. In a variety of organisms, germ cells and stem cells contain large ribonucleoprotein granules. Although these particles were discovered more than 100 years ago, their assembly and functions are not well understood. Here we report that glycolytic enzymes are components of these granules in Drosophila germ cells and both their mRNAs and the enzymes themselves are enriched in germ cells. We show that these enzymes are specifically required for germ cell development and that they protect their genomes from transposable elements, providing the first link between metabolism and transposon silencing. We further demonstrate that in the granules, glycolytic enzymes associate with the evolutionarily conserved Tudor protein. Our biochemical and single-particle EM structural analyses of purified Tudor show a flexible molecule and suggest a mechanism for the recruitment of glycolytic enzymes to the granules. Our data indicate that germ cells, similarly to stem cells and tumor cells, might prefer to produce energy through the glycolytic pathway, thus linking a particular metabolism to pluripotency. © 2015 The Authors.

  8. Arbuscular mycorrhizal fungal inoculation protects Miscanthus × giganteus against trace element toxicity in a highly metal-contaminated site.

    PubMed

    Firmin, Stéphane; Labidi, Sonia; Fontaine, Joël; Laruelle, Frédéric; Tisserant, Benoit; Nsanganwimana, Florian; Pourrut, Bertrand; Dalpé, Yolande; Grandmougin, Anne; Douay, Francis; Shirali, Pirouz; Verdin, Anthony; Lounès-Hadj Sahraoui, Anissa

    2015-09-15

    Arbuscular mycorrhizal fungus (AMF)-assisted phytoremediation could constitute an ecological and economic method in polluted soil rehabilitation programs. The aim of this work was to characterize the trace element (TE) phytoremediation potential of mycorrhizal Miscanthus × giganteus. To understand the mechanisms involved in arbuscular mycorrhizal symbiosis tolerance to TE toxicity, the fatty acid compositions and several stress oxidative biomarkers were compared in the roots and leaves of Miscanthus × giganteus cultivated under field conditions in either TE-contaminated or control soils. TEs were accumulated in greater amounts in roots, but the leaves were the organ most affected by TE contamination and were characterized by a strong decrease in fatty acid contents. TE-induced oxidative stress in leaves was confirmed by an increase in the lipid peroxidation biomarker malondialdehyde (MDA). TE contamination decreased the GSSG/GSH ratio in the leaves of exposed plants, while peroxidase (PO) and superoxide dismutase (SOD) activities were increased in leaves and in whole plants, respectively. AMF inoculation also increased root colonization in the presence of TE contamination. The mycorrhizal colonization determined a decrease in SOD activity in the whole plant and PO activities in leaves and induced a significant increase in the fatty acid content in leaves and a decrease in MDA formation in whole plants. These results suggested that mycorrhization is able to confer protection against oxidative stress induced by soil pollution. Our findings suggest that mycorrhizal inoculation could be used as a bioaugmentation technique, facilitating Miscanthus cultivation on highly TE-contaminated soil.

  9. Vaccination with a recombinant fragment of collagen adhesin provides protection against Staphylococcus aureus-mediated septic death.

    PubMed Central

    Nilsson, I M; Patti, J M; Bremell, T; Höök, M; Tarkowski, A

    1998-01-01

    Staphylococcus aureus is a major cause of nosocomial and community-acquired infections. Morbidity and mortality due to infections such as sepsis, osteomyelitis, septic arthritis, and invasive endocarditis remain high despite the use of antibiotics. The emergence of antibiotic resistant super bugs mandates that alternative strategies for the prevention and treatment of S. aureus infections are developed. We investigated the ability of vaccination with a recombinant fragment of the S. aureus collagen adhesin to protect mice against sepsis-induced death. Actively immunized NMRI mice were intravenously inoculated with the S. aureus clinical isolate strain Phillips. 14 d after inoculation, mortality in the collagen adhesin-vaccinated group was only 13%, compared with 87% in the control antigen immunized group (P < 0.001). To determine if the protective effect was antibody mediated, we passively immunized naive mice with collagen adhesin-specific antibodies. Similar to the active immunization strategy, passive transfer of collagen adhesin-specific antibodies protected mice against sepsis-induced death. In vitro experiments indicated that S. aureus opsonized with sera from collagen adhesin immunized mice promoted phagocytic uptake and enhanced intracellular killing compared with bacteria opsonized with sera from control animals. These results indicate that the collagen adhesin is a viable target in the development of immunotherapeutics against S. aureus. PMID:9637697

  10. Dexamethasone protection of rat intestinal epithelial cells against oxidant injury is mediated by induction of heat shock protein 72.

    PubMed Central

    Urayama, S; Musch, M W; Retsky, J; Madonna, M B; Straus, D; Chang, E B

    1998-01-01

    Although the therapeutic actions of glucocorticoids are largely attributed to their anti-inflammatory and immunosuppressive effects, they have been implicated in enhancing tissue and cellular protection. In this study, we demonstrate that dexamethasone significantly enhances viability of IEC-18 rat small intestinal cells against oxidant-induced stress in a dose-dependent fashion. This protective action is mediated by induction of hsp72, the major inducible heat shock protein in intestinal epithelial cells. Dexamethasone stimulates a time- and dose-dependent response in hsp72 protein expression that parallels its effects on cell viability. Furthermore, the induction of hsp72 is tissue dependent, as nonintestinal epithelioid HeLa cells show differential induction of hsp72 expression in response to the same dexamethasone treatment. Antisense hsp72 cDNA transfection of IEC-18 cells abolishes the dexamethasone-induced hsp72 response, without significantly affecting constitutive expression of its homologue, hsc73. Dexamethasone treatment also significantly induces hsp72 protein expression in rat intestinal mucosal cells in vivo. These data demonstrate that glucocorticoids protect intestinal epithelial cells against oxidant-induced stress by inducing hsp72. PMID:9819372

  11. Gut microbiota in Drosophila melanogaster interacts with Wolbachia but does not contribute to Wolbachia-mediated antiviral protection.

    PubMed

    Ye, Yixin H; Seleznev, Andrei; Flores, Heather A; Woolfit, Megan; McGraw, Elizabeth A

    2017-02-01

    Animals experience near constant infection with microorganisms. A significant proportion of these microbiota reside in the alimentary tract. There is a growing appreciation for the roles gut microbiota play in host biology. The gut microbiota of insects, for example, have been shown to help the host overcome pathogen infection either through direct competition or indirectly by stimulating host immunity. These defenses may also be supplemented by coinfecting maternally inherited microbes such as Wolbachia. The presence of Wolbachia in a host can delay and/or reduce death caused by RNA viruses. Whether the gut microbiota of the host interacts with Wolbachia, or vice versa, the precise role of Wolbachia in antiviral protection is not known. In this study, we used 16S rDNA sequencing to characterise changes in gut microbiota composition in Drosophila melanogaster associated with Wolbachia infection and antibiotic treatment. We subsequently tested whether changes in gut composition via antibiotic treatment altered Wolbachia-mediated antiviral properties. We found that both antibiotics and Wolbachia significantly reduced the biodiversity of the gut microbiota without changing the total microbial load. We also showed that changing the gut microbiota composition with antibiotic treatment enhanced Wolbachia density but did not confer greater antiviral protection against Drosophila C virus to the host. We concluded there are significant interactions between Wolbachia and gut microbiota, but changing gut microbiota composition is not likely to be a means through which Wolbachia conveys antiviral protection to its host.

  12. Optimism and the brain: trait optimism mediates the protective role of the orbitofrontal cortex gray matter volume against anxiety.

    PubMed

    Dolcos, Sanda; Hu, Yifan; Iordan, Alexandru D; Moore, Matthew; Dolcos, Florin

    2016-02-01

    Converging evidence identifies trait optimism and the orbitofrontal cortex (OFC) as personality and brain factors influencing anxiety, but the nature of their relationships remains unclear. Here, the mechanisms underlying the protective role of trait optimism and of increased OFC volume against symptoms of anxiety were investigated in 61 healthy subjects, who completed measures of trait optimism and anxiety, and underwent structural scanning using magnetic resonance imaging. First, the OFC gray matter volume (GMV) was associated with increased optimism, which in turn was associated with reduced anxiety. Second, trait optimism mediated the relation between the left OFC volume and anxiety, thus demonstrating that increased GMV in this brain region protects against symptoms of anxiety through increased optimism. These results provide novel evidence about the brain-personality mechanisms protecting against anxiety symptoms in healthy functioning, and identify potential targets for preventive and therapeutic interventions aimed at reducing susceptibility and increasing resilience against emotional disturbances. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  13. The Evolutionarily Conserved Mediator Subunit MDT-15/MED15 Links Protective Innate Immune Responses and Xenobiotic Detoxification

    PubMed Central

    McEwan, Deborah L.; Conery, Annie L.; Ausubel, Frederick M.

    2014-01-01

    Metazoans protect themselves from environmental toxins and virulent pathogens through detoxification and immune responses. We previously identified a small molecule xenobiotic toxin that extends survival of Caenorhabditis elegans infected with human bacterial pathogens by activating the conserved p38 MAP kinase PMK-1 host defense pathway. Here we investigate the cellular mechanisms that couple activation of a detoxification response to innate immunity. From an RNAi screen of 1,420 genes expressed in the C. elegans intestine, we identified the conserved Mediator subunit MDT-15/MED15 and 28 other gene inactivations that abrogate the induction of PMK-1-dependent immune effectors by this small molecule. We demonstrate that MDT-15/MED15 is required for the xenobiotic-induced expression of p38 MAP kinase PMK-1-dependent immune genes and protection from Pseudomonas aeruginosa infection. We also show that MDT-15 controls the induction of detoxification genes and functions to protect the host from bacteria-derived phenazine toxins. These data define a central role for MDT-15/MED15 in the coordination of xenobiotic detoxification and innate immune responses. PMID:24875643

  14. Vaccine and serum-mediated protection against brucella infection of mouse placenta.

    PubMed Central

    Bosseray, N.

    1983-01-01

    Pregnant mice inoculated i.p. or i.v. with virulent Brucella abortus Strain 544 displayed strong infection, evidenced by brucella enumeration in placentas and dams' spleens. Vaccination 1 month before pregnancy decreased frequency of placental colonization and number of brucella per infected placenta and per spleen. Protein-bound cell wall peptidoglycan (PG) fractions extracted from brucella protected mice as well as H38 killed and B19 attenuated living vaccines. The lipopolysaccharide (LPS) fraction was comparatively less active. Immune serum injected i.v., either 24 h before or just after i.v. challenge of 15-day pregnant mice effectively transferred resistance to placental colonization. Anti LPS, anti PG and anti killed brucella sera protected mice as well as vaccination one month before pregnancy. The immunity transferred persisted for at least 3 days. PMID:6419766

  15. Glucocorticoid receptor in T cells mediates protection from autoimmunity in pregnancy

    PubMed Central

    Engler, Jan Broder; Kursawe, Nina; Solano, María Emilia; Patas, Kostas; Wehrmann, Sabine; Heckmann, Nina; Lühder, Fred; Reichardt, Holger M.; Arck, Petra Clara; Gold, Stefan M.

    2017-01-01

    Pregnancy is one of the strongest inducers of immunological tolerance. Disease activity of many autoimmune diseases including multiple sclerosis (MS) is temporarily suppressed by pregnancy, but little is known about the underlying molecular mechanisms. Here, we investigated the endocrine regulation of conventional and regulatory T cells (Tregs) during reproduction. In vitro, we found the pregnancy hormone progesterone to robustly increase Treg frequencies via promiscuous binding to the glucocorticoid receptor (GR) in T cells. In vivo, T-cell–specific GR deletion in pregnant animals undergoing experimental autoimmune encephalomyelitis (EAE), the animal model of MS, resulted in a reduced Treg increase and a selective loss of pregnancy-induced protection, whereas reproductive success was unaffected. Our data imply that steroid hormones can shift the immunological balance in favor of Tregs via differential engagement of the GR in T cells. This newly defined mechanism confers protection from autoimmunity during pregnancy and represents a potential target for future therapy. PMID:28049829

  16. Immunological mechanisms underlying protection mediated by RTS,S: a review of the available data

    PubMed Central

    2009-01-01

    The RTS,S/AS candidate malaria vaccine has demonstrated efficacy against a variety of endpoints in Phase IIa and Phase IIb trials over more than a decade. A multi-country phase III trial of RTS,S/AS01 is now underway with submission as early as 2012, if vaccine safety and efficacy are confirmed. The immunologic basis for how the vaccine protects against both infection and disease remains uncertain. It is, therefore, timely to review the information currently available about the vaccine with regard to how it impacts the human-Plasmodium falciparum host-pathogen relationship. In this article, what is known about mechanisms involved in partial protection against malaria induced by RTS,S is reviewed. PMID:20042088

  17. NK Cell-Mediated Regulation of Protective Memory Responses against Intracellular Ehrlichial Pathogens

    PubMed Central

    Habib, Samar; El Andaloussi, Abdeljabar; Hisham, Ahmed; Ismail, Nahed

    2016-01-01

    Ehrlichiae are gram-negative obligate intracellular bacteria that cause potentially fatal human monocytic ehrlichiosis. We previously showed that natural killer (NK) cells play a critical role in host defense against Ehrlichia during primary infection. However, the contribution of NK cells to the memory response against Ehrlichia remains elusive. Primary infection of C57BL/6 mice with Ehrlichia muris provides long-term protection against a second challenge with the highly virulent Ixodes ovatus Ehrlichia (IOE), which ordinarily causes fatal disease in naïve mice. Here, we show that the depletion of NK cells in E. muris-primed mice abrogates the protective memory response against IOE. Approximately, 80% of NK cell-depleted E. muris-primed mice succumbed to lethal IOE infection on days 8–10 after IOE infection, similar to naïve mice infected with the same dose of IOE. The lack of a recall response in NK cell-depleted mice correlated with an increased bacterial burden, extensive liver injury, decreased frequency of Ehrlichia-specific IFN-γ-producing memory CD4+ and CD8+ T-cells, and a low titer of Ehrlichia-specific antibodies. Intraperitoneal infection of mice with E. muris resulted in the production of IL-15, IL-12, and IFN-γ as well as an expansion of activated NKG2D+ NK cells. The adoptive transfer of purified E. muris-primed hepatic and splenic NK cells into Rag2-/-Il2rg-/- recipient mice provided protective immunity against challenge with E. muris. Together, these data suggest that E. muris-induced memory-like NK cells, which contribute to the protective, recall response against Ehrlichia. PMID:27092553

  18. Suicidal inactivation of methemoglobin by generation of thiyl radical: insight into NAC mediated protection in RBC.

    PubMed

    Balaji, S N; Trivedi, V

    2013-07-01

    N-acetyl-L-cysteine (NAC) improves antioxidant potentials of RBCs to provide protection against oxidative stress induced hemolysis. The antioxidant mechanism of NAC to reduce oxidative stress in RBC, studied through inactivation of pro-oxidant MetHb. NAC causes irreversible inactivation of the MetHb in an H2O2 dependent manner, and the inactivation follows the pseudo- first- order kinetics. The kinetic constants are ki = 8.5μM, kinact = 0.706 min(-1) and t1/2 = 0.9 min. Spectroscopic studies indicate that MetHb accepts NAC as a substrate and oxidizes through a single electron transfer mechanism to the NACox. The single e- oxidation product of NAC has been identified as the 5, 5'- dimethyl-1- pyrroline N- oxide (DMPO) adduct of the sulfur centered radical (a(N) = 15.2 G and a(H)=16.78 G). Binding studies indicate that NACox interacts at the heme moiety and NAC oxidation through MetHb is essential for NAC binding. Heme-NAC adduct dissociated from MetHb and identified (m/z 1011.19) as 2:1 ratio of NAC/heme in the adduct. TEMPO and PBN treatment reduces NAC binding to MetHb and protects against inactivation confirms the role of thiyl radical in the inactivation process. Furthermore, scavenging thiyl radicals by TEMPO abolish the protective effect of NAC in hemolysis. Current work highlights antioxidant mechanism of NAC through NAC thiyl radical generation, and MetHb inactivation to exhibit protection in RBC against oxidative stress induced hemolysis.

  19. The Mutualistic Side of Wolbachia–Isopod Interactions: Wolbachia Mediated Protection Against Pathogenic Intracellular Bacteria

    PubMed Central

    Braquart-Varnier, Christine; Altinli, Mine; Pigeault, Romain; Chevalier, Frédéric D.; Grève, Pierre; Bouchon, Didier; Sicard, Mathieu

    2015-01-01

    Wolbachia is a vertically transmitted endosymbiont whose radiative success is mainly related to various host reproductive manipulations that led to consider this symbiont as a conflictual reproductive parasite. However, lately, some Wolbachia have been shown to act as beneficial symbionts by protecting hosts against a broad range of parasites. Still, this protection has been mostly demonstrated in artificial Wolbachia-host associations between partners that did not co-evolved together. Here, we tested in two terrestrial isopod species Armadillidium vulgare and Porcellio dilatatus whether resident Wolbachia (native or non-native) could confer protection during infections with Listeria ivanovii and Salmonella typhimurium and also during a transinfection with a Wolbachia strain that kills the recipient host (i.e., wVulC in P. dilatatus). Survival analyses showed that (i) A. vulgare lines hosting their native Wolbachia (wVulC) always exhibited higher survival than asymbiotic ones when infected with pathogenic bacteria (ii) P. dilatatus lines hosting their native wDil Wolbachia strain survived the S. typhimurium infection better, while lines hosting non-native wCon Wolbachia strain survived the L. ivanovii and also the transinfection with wVulC from A. vulgare better. By studying L. ivanovii and S. typhimurium loads in the hemolymph of the different host-Wolbachia systems, we showed that (i) the difference in survival between lines after L. ivanovii infections were not linked to the difference between their pathogenic bacterial loads, and (ii) the difference in survival after S. typhimurium infections corresponds to lower loads of pathogenic bacteria. Overall, our results demonstrate a beneficial effect of Wolbachia on survival of terrestrial isopods when infected with pathogenic intracellular bacteria. This protective effect may rely on different mechanisms depending on the resident symbiont and the invasive bacteria interacting together within the hosts. PMID:26733946

  20. Antioxidant-mediated protective effect of potato peel extract in erythrocytes against oxidative damage.

    PubMed

    Singh, Nandita; Rajini, P S

    2008-05-28

    Potato peels are waste by-product of the potato processing industry. They are reportedly rich in polyphenols. Our earlier studies have shown that extracts derived from potato peel (PPE) possess strong antioxidant activity in chemical and biological model systems in vitro, attributable to its polyphenolic content. The main objective of this study was to investigate the ability of PPE to protect erythrocytes against oxidative damage, in vitro. The protection rendered by PPE in erythrocytes was studied in terms of resistance to oxidative damage, morphological alterations as well as membrane structural alterations. The total polyphenolic content in PPE was found to be 3.93 mg/g powder. The major phenolic acids present in PPE were predominantly: gallic acid, caffeic acid, chlorogenic acid and protocatechuic acid. We chose the experimental prooxidant system: FeSO(4) and ascorbic acid to induce lipid peroxidation in rat RBCs and human RBC membranes. PPE was found to inhibit lipid peroxidation with similar effectiveness in both the systems (about 80-85% inhibition by PPE at 2.5 mg/ml). While PPE per se did not cause any morphological alteration in the erythrocytes, under the experimental conditions, PPE significantly inhibited the H(2)O(2)-induced morphological alterations in rat RBCs as revealed by scanning electron microscopy. Further, PPE was found to offer significant protection to human erythrocyte membrane proteins from oxidative damage induced by ferrous-ascorbate. In conclusion, our results indicate that PPE is capable of protecting erythrocytes against oxidative damage probably by acting as a strong antioxidant.

  1. Antioxidant mediated protective effect of Parthenium hysterophorus against oxidative damage using in vitro models

    PubMed Central

    2013-01-01

    Background Parthenium hysterophorus L. (Asteraceae) is a common weed occurring throughout the globe. In traditional medicine its decoction has been used for treatment of many infectious and degenerative diseases. This work was therefore designed to assess the phytochemical constitution of P. hysterophorus flower and root extracts and to evaluate their reducing power, radical scavenging activity as well as protective efficacy against membrane lipid damage. Methods Dried flower and root samples were sequentially extracted with non-polar and polar solvents using Soxhlet apparatus. The phytochemical screening was done using standard chemical methods and thin layer chromatography. Total phenolic content was determined spectrophotometrically. Reducing power and hydroxyl radical scavenging activity assays were used to measure antioxidant activity. Protection against membrane damage was evaluated by inhibition of lipid peroxidation (TBARS assay) in rat kidney homogenate. Results Flavonoids, terpenoids, alkaloids and cardiac glycosides were present in all the extract. The total phenol contents in flower and root extracts were found to be in the range 86.69-320.17 mg propyl gallate equivalent (PGE)/g and 55.47-253.84 mg PGE/g, respectively. Comparatively better reducing power was observed in hexane fractions of flower (0.405) and root (0.282). Benzene extract of flower and ethyl acetate fraction of root accounted for appreciable hydroxyl radical scavenging activity (75-77%). Maximum protection against membrane lipid peroxidative damage among flower and root extracts was provided by ethanol (55.26%) and ethyl acetate (48.95%) fractions, respectively. Total phenolic content showed positive correlations with reducing power and lipid peroxidation inhibition (LPOI) % in floral extracts as well as with hydroxyl radical scavenging activity and LPOI % in root extracts. Conclusion Study established that phytochemicals present in P. hysterophorus extracts have considerable antioxidant

  2. Phospholipid scramblase 1 mediates type i interferon-induced protection against staphylococcal α-toxin.

    PubMed

    Lizak, Miroslaw; Yarovinsky, Timur O

    2012-01-19

    The opportunistic gram-positive pathogen Staphylococcus aureus is a leading cause of pneumonia and sepsis. Staphylococcal α-toxin, a prototypical pore-forming toxin, is a major virulence factor of S. aureus clinical isolates, and lung epithelial cells are highly sensitive to α-toxin's cytolytic activity. Type I interferon (IFN) signaling activated in response to S. aureus increases pulmonary cell resistance to α-toxin, but the underlying mechanisms are uncharacterized. We show that IFNα protects human lung epithelial cells from α-toxin-induced intracellular ATP depletion and cell death by reducing extracellular ATP leakage. This effect depends on protein palmitoylation and induction of phospholipid scramblase 1 (PLSCR1). IFNα-induced PLSCR1 associates with the cytoskeleton after exposure to α-toxin, and cellular depletion of PLSCR1 negates IFN-induced protection from α-toxin. PLSCR1-deficient mice display enhanced sensitivity to inhaled α-toxin and an α-toxin-producing S. aureus strain. These results uncover PLSCR1 activity as part of an innate protective mechanism to a bacterial pore-forming toxin. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Phospholipid scramblase 1 mediates type I interferon-induced protection against staphylococcal α-toxin

    PubMed Central

    Lizak, Miroslaw; Yarovinsky, Timur O.

    2012-01-01

    Summary The opportunistic gram-positive pathogen Staphylococcus aureus is a leading cause of pneumonia and sepsis. Staphylococcal α-toxin, a prototypical pore-forming toxin, is a major virulence factor of S. aureus clinical isolates and lung epithelial cells are highly sensitive to α-toxin's cytolytic activity. Type I interferon (IFN) signaling activated in response to S. aureus increases pulmonary cell resistance to α-toxin but the underlying mechanisms are uncharacterized. We show that IFNα protects human lung epithelial cells from α-toxin-induced intracellular ATP depletion and cell death by reducing extracellular ATP leakage. This effect depends on protein palmitoylation and induction of phospholipid scramblase 1 (PLSCR1). IFNα-induced PLSCR1 associates with the cytoskeleton after exposure to α-toxin and cellular depletion of PLSCR1 negates IFN-induced protection from α-toxin. PLSCR1-deficient mice display enhanced sensitivity to inhaled α-toxin and an α-toxin-producing S. aureus strain. These results uncover PLSCR1 activity as part of an innate protective mechanism to a bacterial pore-forming toxin. PMID:22264514

  4. Endophytic Fungi Piriformospora indica Mediated Protection of Host from Arsenic Toxicity

    PubMed Central

    Mohd, Shayan; Shukla, Jagriti; Kushwaha, Aparna S.; Mandrah, Kapil; Shankar, Jai; Arjaria, Nidhi; Saxena, Prem N.; Narayan, Ram; Roy, Somendu K.; Kumar, Manoj

    2017-01-01

    Complex intercellular interaction is a common theme in plant-pathogen/symbiont relationship. Cellular physiology of both the partners is affected by abiotic stress. However, little is known about the degree of protection each offers to the other from different types of environmental stress. Our current study focused on the changes in response to toxic arsenic in the presence of an endophytic fungus Piriformospora indica that colonizes the paddy roots. The primary impact of arsenic was observed in the form of hyper-colonization of fungus in the host root and resulted in the recovery of its overall biomass, root damage, and chlorophyll due to arsenic toxicity. Further, fungal colonization leads to balance the redox status of the cell by adjusting the antioxidative enzyme system which in turn protects photosynthetic machinery of the plant from arsenic stress. We observed that fungus has ability to immobilize soluble arsenic and interestingly, it was also observed that fungal colonization restricts most of arsenic in the colonized root while a small fraction of it translocated to shoot of colonized plants. Our study suggests that P. indica protects the paddy (Oryza sativa) from arsenic toxicity by three different mechanisms viz. reducing the availability of free arsenic in the plant environment, bio-transformation of the toxic arsenic salts into insoluble particulate matter and modulating the antioxidative system of the host cell. PMID:28539916

  5. Protective effects of nonionic tri-block copolymers on bile acid-mediated epithelial barrier disruption.

    SciTech Connect

    Edelstein, A.; Fink, D.; Musch, M.; Valuckaite, V.; Zabornia, O.; Grubjesic, S.; Firestone, M. A.; Matthews, J. B.; Alverdy, J. C.

    2011-11-01

    Translocation of bacteria and other luminal factors from the intestine following surgical injury can be a major driver of critical illness. Bile acids have been shown to play a key role in the loss of intestinal epithelial barrier function during states of host stress. Experiments to study the ability of nonionic block copolymers to abrogate barrier failure in response to bile acid exposure are described. In vitro experiments were performed with the bile salt sodium deoxycholate on Caco-2 enterocyte monolayers using transepithelial electrical resistance to assay barrier function. A bisphenol A coupled triblock polyethylene glycol (PEG), PEG 15-20, was shown to prevent sodium deoxycholate-induced barrier failure. Enzyme-linked immunosorbent assay, lactate dehydrogenase, and caspase 3-based cell death detection assays demonstrated that bile acid-induced apoptosis and necrosis were prevented with PEG 15-20. Immunofluorescence microscopic visualization of the tight junctional protein zonula occludens 1 (ZO-1) demonstrated that PEG 15-20 prevented significant changes in tight junction organization induced by bile acid exposure. Preliminary transepithelial electrical resistance-based studies examining structure-function correlates of polymer protection against bile acid damage were performed with a small library of PEG-based copolymers. Polymer properties associated with optimal protection against bile acid-induced barrier disruption were PEG-based compounds with a molecular weight greater than 10 kd and amphiphilicity. The data demonstrate that PEG-based copolymer architecture is an important determinant that confers protection against bile acid injury of intestinal epithelia.

  6. Heat Stress Affects Facultative Symbiont-Mediated Protection from a Parasitoid Wasp

    PubMed Central

    Heyworth, Eleanor R.

    2016-01-01

    Many insects carry facultative bacterial symbionts, which provide benefits including resistance to natural enemies and abiotic stresses. Little is known about how these beneficial phenotypes are affected when biotic or abiotic threats occur simultaneously. The pea aphid (Acyrthosiphon pisum) can host several well-characterized symbiont species. The symbiont known as X-type can protect against both parasitoid wasps and heat stress. Here, we used three pea aphid genotypes that were naturally infected with X-type and the symbiont Spiroplasma sp. We compared aphids coinfected with these two symbionts with those cured from X-type and infected with only Spiroplasma to investigate the ability of X-type to confer benefits to the host when two threats are experienced simultaneously. Our aim is to explore how robust symbiont protection may be outside a benign laboratory environment. Aphids were subjected to heat shock either before or after attack by parasitoid wasps. Under a benign temperature regime, the aphids carrying X-type tended to be better protected from the parasitoid than those cured. When the aphids experienced a heat shock before being parasitized aphids carrying X-type were more susceptible than those cured. Regardless of infection with the symbiont, the aphids benefitted from being heat shocked after parasitization. The results demonstrate how resistance to parasitoid wasps can be strongly environment-dependent and that a beneficial phenotype conferred by a symbiont under controlled conditions in the laboratory does not necessarily equate to a consistently useful effect in natural populations. PMID:27875577

  7. Airway Memory CD4+ T Cells Mediate Protective Immunity against Emerging Respiratory Coronaviruses

    PubMed Central

    Zhao, Jincun; Zhao, Jingxian; Mangalam, Ashutosh K.; Channappanavar, Rudragouda; Fett, Craig; Meyerholz, David K.; Agnihothram, Sudhakar; Baric, Ralph S.; David, Chella S.; Perlman, Stanley

    2016-01-01

    SUMMARY Two zoonotic coronaviruses (CoV), SARS-CoV and MERS-CoV have crossed species to cause severe human respiratory disease. Here, we showed that induction of airway memory CD4+ T cells specific for a conserved epitope shared by SARS-CoV and MERS-CoV is a potential strategy for developing pan-coronavirus vaccines. Airway memory CD4+ T cells differed phenotypically and functionally from lung-derived cells and were crucial for protection against both CoVs in mice. Protection was interferon-γ-dependent and required early induction of robust innate and virus-specific CD8+ T cell responses. The conserved epitope was also recognized in SARS-CoV and MERS-CoV-infected human leukocyte antigen DR2 and DR3 transgenic mice, indicating potential relevance in human populations. Additionally, this epitope was cross-protective between human and bat CoVs, the progenitors for many human CoVs. Vaccine strategies that induce airway memory CD4+ T cells targeting conserved epitopes may have broad applicability in the context of new CoV and other respiratory virus outbreaks. PMID:27287409

  8. Airway Memory CD4(+) T Cells Mediate Protective Immunity against Emerging Respiratory Coronaviruses.

    PubMed

    Zhao, Jincun; Zhao, Jingxian; Mangalam, Ashutosh K; Channappanavar, Rudragouda; Fett, Craig; Meyerholz, David K; Agnihothram, Sudhakar; Baric, Ralph S; David, Chella S; Perlman, Stanley

    2016-06-21

    Two zoonotic coronaviruses (CoVs)-SARS-CoV and MERS-CoV-have crossed species to cause severe human respiratory disease. Here, we showed that induction of airway memory CD4(+) T cells specific for a conserved epitope shared by SARS-CoV and MERS-CoV is a potential strategy for developing pan-coronavirus vaccines. Airway memory CD4(+) T cells differed phenotypically and functionally from lung-derived cells and were crucial for protection against both CoVs in mice. Protection was dependent on interferon-γ and required early induction of robust innate and virus-specific CD8(+) T cell responses. The conserved epitope was also recognized in SARS-CoV- and MERS-CoV-infected human leukocyte antigen DR2 and DR3 transgenic mice, indicating potential relevance in human populations. Additionally, this epitope was cross-protective between human and bat CoVs, the progenitors for many human CoVs. Vaccine strategies that induce airway memory CD4(+) T cells targeting conserved epitopes might have broad applicability in the context of new CoVs and other respiratory virus outbreaks. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. CP12-mediated protection of Calvin-Benson cycle enzymes from oxidative stress.

    PubMed

    Marri, Lucia; Thieulin-Pardo, Gabriel; Lebrun, Régine; Puppo, Rémy; Zaffagnini, Mirko; Trost, Paolo; Gontero, Brigitte; Sparla, Francesca

    2014-02-01

    Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoribulokinase (PRK) are two energy-consuming enzymes of the Calvin-Benson cycle, whose regulation is crucial for the global balance of the photosynthetic process under different environmental conditions. In oxygen phototrophs, GAPDH and PRK regulation involves the redox-sensitive protein CP12. In the dark, oxidized chloroplast thioredoxins trigger the formation of a GAPDH/CP12/PRK complex in which both enzyme activities are down-regulated. In this report, we show that free GAPDH (A4-isoform) and PRK are also inhibited by oxidants like H2O2, GSSG and GSNO. Both in the land plant Arabidopsis thaliana and in the green microalga Chlamydomonas reinhardtii, both enzymes can be glutathionylated as shown by biotinylated-GSSG assay and MALDI-ToF mass spectrometry. CP12 is not glutathionylated but homodisulfides are formed upon oxidant treatments. In Arabidopsis but not in Chlamydomonas, the interaction between oxidized CP12 and GAPDH provides full protection from oxidative damage. In both organisms, preformed GAPDH/CP12/PRK complexes are protected from GSSG or GSNO oxidation, and in Arabidopsis also from H2O2 treatment. Overall, the results suggest that the role of CP12 in oxygen phototrophs needs to be extended beyond light/dark regulation, and include protection of enzymes belonging to Calvin-Benson cycle from oxidative stress. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  10. The materials and elements production practice of counter-erosional and thermal protection system of the SPR-solid-propellant sustainer nozzle

    NASA Astrophysics Data System (ADS)

    Shkurenko, V. M.

    1993-06-01

    This paper presents the production scheme for heat- and erosion-protective carbon plastic materials for heat shield elements of solid-propellant nozzles. Attention is also given the method of manufacturing adhesive joint assemblies, and the production scheme is included.

  11. Major histocompatibility class I gene transcription in thyrocytes: a series of interacting regulatory DNA sequence elements mediate thyrotropin/cyclic adenosine 3',5'-monophosphate repression.

    PubMed

    Kirshner, S; Palmer, L; Bodor, J; Saji, M; Kohn, L D; Singer, D S

    2000-01-01

    In response to TSH, thyroid cells decrease major histocompatibility (MHC) class I expression and transcription, providing an excellent model for studying the dynamic modulation of transcription of MHC class I genes. Here we show that protein kinase A (PKA), a downstream effector of the TSH/cAMP pathway, reproduces the effects of TSH in repressing class I transcription. PKA/cAMP-mediated repression of transcription involves multiple interacting upstream response elements in the class I promoter: an element extending from -127 to -90 bp containing a CRE-like core, and at least two elements within an upstream 30-bp segment (-160 to -130 bp), which overlaps with the interferon regulatory element. ICER (inducible cAMP early response), a transcriptional repressor induced by TSH/cAMP can decrease class I promoter activity when introduced into FRTL-5 thyroid cells in the absence of TSH/cAMP. ICER binds to both the CRE-like element and the upstream 30-bp segment, generating a novel TSH-induced ternary complex. The present studies led to the proposal that TSH-mediated repression of class I transcription is the result of integrating signals from transcription factors through the higher order interactions of multiple regulatory elements.

  12. Experimental immunologically mediated aplastic anemia (AA) in mice: cyclosporin A fails to protect against AA

    SciTech Connect

    Knospe, W.H.; Steinberg, D.; Gratwohl, A.; Speck, B.

    1984-07-01

    Immunologically mediated aplastic anemia (AA) in mice was induced by the i.v. injection of 10(7) lymph node cells (LNC) from H-2k identical but Mls mismatched CBA/J donor mice into previously irradiated (600 rad total body gamma) C3H/HeJ mice. Cyclosporin A (CsA), 25 mg/kg, was administered subcutaneously from day -1 to day 30. Control mice included C3H/HeJ mice which received 600 rad alone, C3H/HeJ mice which received 600 rad plus CsA as above, and C3H/HeJ mice which received 600 rad total body irradiation followed by 10(7) LNC from CBA/J donors. CsA failed to prevent lethal AA. These results suggest that the pathogenetic mechanisms operating in immunologically mediated AA differ from the mechanisms operating in rodents transplanted with allogeneically mismatched marrow or spleen cells which develop graft-versus-host disease. The results are consistent with a non-T cell-dependent mechanism causing the AA.

  13. Macrophage-mediated GDNF Delivery Protects Against Dopaminergic Neurodegeneration: A Therapeutic Strategy for Parkinson's Disease

    PubMed Central

    Biju, KC; Zhou, Qing; Li, Guiming; Imam, Syed Z; Roberts, James L; Morgan, William W; Clark, Robert A; Li, Senlin

    2010-01-01

    Glial cell line–derived neurotrophic factor (GDNF) has emerged as the most potent neuroprotective agent tested in experimental models for the treatment of Parkinson's disease (PD). However, its use is hindered by difficulties in delivery to the brain due to the presence of the blood–brain barrier (BBB). In order to circumvent this problem, we took advantage of the fact that bone marrow stem cell–derived macrophages are able to pass the BBB and home to sites of neuronal degeneration. Here, we report the development of a method for brain delivery of GDNF by genetically modified macrophages. Bone marrow stem cells were transduced ex vivo with lentivirus expressing a GDNF gene driven by a synthetic macrophage-specific promoter and then transplanted into recipient mice. Eight weeks after transplantation, the mice were injected with the neurotoxin, MPTP, for 7 days to induce dopaminergic neurodegeneration. Macrophage-mediated GDNF treatment dramatically ameliorated MPTP-induced degeneration of tyrosine hydroxylase (TH)-positive neurons of the substantia nigra and TH+ terminals in the striatum, stimulated axon regeneration, and reversed hypoactivity in the open field test. These results indicate that macrophage-mediated GDNF delivery is a promising strategy for developing a neuroprotective therapy for PD. PMID:20531393

  14. CD11b is protective in complement-mediated immune complex glomerulonephritis.

    PubMed

    Alexander, Jessy J; Chaves, Lee D; Chang, Anthony; Jacob, Alexander; Ritchie, Maria; Quigg, Richard J

    2015-05-01

    In chronic serum sickness, glomerular immune complexes form, yet C57BL/6 mice do not develop glomerulonephritis unless complement factor H (CfH) is absent, indicating the relevance of complement regulation. Complement receptor 3 (CD11b) and Fcγ receptors on leukocytes, and CfH on platelets, can bind immune complexes. Here we induced immune complex-mediated glomerulonephritis in CfH(-/-) mice chimeric for wild-type, CfH(-/-), CD11b(-/-), or FcRγ(-/-) bone marrow stem cells. Glomerulonephritis was worse in CD11b(-/-) chimeras compared with all others, whereas disease in FcRγ(-/-) and wild-type chimeras was comparable. Disease tracked strongly with humoral immune responses, but not glomerular immune complex deposits. Interstitial inflammation with M1 macrophages strongly correlated with glomerulonephritis scores. CD11b(-/-) chimeras had significantly more M1 macrophages and CD4(+) T cells. The renal dendritic cell populations originating from bone marrow-derived CD11c(+) cells were similar in all experimental groups. CD11b(+) cells bearing colony-stimulating factor 1 receptor were present in kidneys, including CD11b(-/-) chimeras; these cells correlated negatively with glomerulonephritis scores. Thus, experimental immune complex-mediated glomerulonephritis is associated with accumulation of M1 macrophages and CD4(+) T cells in kidneys and functional renal insufficiency. Hence, CD11b on mononuclear cells is instrumental in generating an anti-inflammatory response in the inflamed kidney.

  15. The Potential Protective Effects of Polyphenols in Asbestos-Mediated Inflammation and Carcinogenesis of Mesothelium

    PubMed Central

    Benvenuto, Monica; Mattera, Rosanna; Taffera, Gloria; Giganti, Maria Gabriella; Lido, Paolo; Masuelli, Laura; Modesti, Andrea; Bei, Roberto

    2016-01-01

    Malignant Mesothelioma (MM) is a tumor of the serous membranes linked to exposure to asbestos. A chronic inflammatory response orchestrated by mesothelial cells contributes to the development and progression of MM. The evidence that: (a) multiple signaling pathways are aberrantly activated in MM cells; (b) asbestos mediated-chronic inflammation has a key role in MM carcinogenesis; (c) the deregulation of the immune system might favor the development of MM; and (d) a drug might have a better efficacy when injected into a serous cavity thus bypassing biotransformation and reaching an effective dose has prompted investigations to evaluate the effects of polyphenols for the therapy and prevention of MM. Dietary polyphenols are able to inhibit cancer cell growth by targeting multiple signaling pathways, reducing inflammation, and modulating immune response. The ability of polyphenols to modulate the production of pro-inflammatory molecules by targeting signaling pathways or ROS might represent a key mechanism to prevent and/or to contrast the development of MM. In this review, we will report the current knowledge on the ability of polyphenols to modulate the immune system and production of mediators of inflammation, thus revealing an important tool in preventing and/or counteracting the growth of MM. PMID:27171110

  16. The Potential Protective Effects of Polyphenols in Asbestos-Mediated Inflammation and Carcinogenesis of Mesothelium.

    PubMed

    Benvenuto, Monica; Mattera, Rosanna; Taffera, Gloria; Giganti, Maria Gabriella; Lido, Paolo; Masuelli, Laura; Modesti, Andrea; Bei, Roberto

    2016-05-09

    Malignant Mesothelioma (MM) is a tumor of the serous membranes linked to exposure to asbestos. A chronic inflammatory response orchestrated by mesothelial cells contributes to the development and progression of MM. The evidence that: (a) multiple signaling pathways are aberrantly activated in MM cells; (b) asbestos mediated-chronic inflammation has a key role in MM carcinogenesis; (c) the deregulation of the immune system might favor the development of MM; and (d) a drug might have a better efficacy when injected into a serous cavity thus bypassing biotransformation and reaching an effective dose has prompted investigations to evaluate the effects of polyphenols for the therapy and prevention of MM. Dietary polyphenols are able to inhibit cancer cell growth by targeting multiple signaling pathways, reducing inflammation, and modulating immune response. The ability of polyphenols to modulate the production of pro-inflammatory molecules by targeting signaling pathways or ROS might represent a key mechanism to prevent and/or to contrast the development of MM. In this review, we will report the current knowledge on the ability of polyphenols to modulate the immune system and production of mediators of inflammation, thus revealing an important tool in preventing and/or counteracting the growth of MM.

  17. A Ubiquitous Chromatin Opening Element (UCOE) Confers Resistance to DNA Methylation–mediated Silencing of Lentiviral Vectors

    PubMed Central

    Zhang, Fang; Frost, Amy R; Blundell, Mike P; Bales, Olivia; Antoniou, Michael N; Thrasher, Adrian J

    2010-01-01

    DNA methylation may restrict the activity of gene transfer vectors due to inadvertent silencing. In P19 embryonic carcinoma cells in vitro, we found that transgene expression regulated by the SFFV LTR and EF1α promoter declined rapidly within 16 days, but for A2UCOE derived from the human HNRPA2B1-CBX3 housekeeping gene locus, remained completely stable. Silencing correlated with extensive epigenetic methylation of CpG sites, whereas the A2UCOE was almost completely resistant. Linking of the A2UCOE upstream of the SFFV LTR protected this element from both DNA methylation and silencing. Analysis of engrafted hematopoietic cells in vivo transduced with the same vectors revealed a similar pattern. The A2UCOE displayed little or no methylation in either primary or secondary graft recipients, and gene expression profiles were highly conserved between the two groups. These studies provide convincing evidence that DNA methylation plays a direct role in regulating self-inactivating (SIN) lentiviral transgene expression, and that the stability of expression from the A2UCOE is, at least in part, due to methylation resistance. The A2UCOE therefore has considerable utility for gene therapy applications where reliable and sustained gene expression is desirable. PMID:20588258

  18. Novel plant virus-based vaccine induces protective cytotoxic T-lymphocyte-mediated antiviral immunity through dendritic cell maturation.

    PubMed

    Lacasse, Patrick; Denis, Jérôme; Lapointe, Réjean; Leclerc, Denis; Lamarre, Alain

    2008-01-01

    Currently used vaccines protect mainly through the production of neutralizing antibodies. However, antibodies confer little or no protection for a majority of chronic viral infections that require active involvement of cytotoxic T lymphocytes (CTLs). Virus-like particles (VLPs) have been shown to be efficient inducers of cell-mediated immune responses, but administration of an adjuvant is generally required. We recently reported the generation of a novel VLP system exploiting the self-assembly property of the papaya mosaic virus (PapMV) coat protein. We show here that uptake of PapMV-like particles by murine splenic dendritic cells (DCs) in vivo leads to their maturation, suggesting that they possess intrinsic adjuvant-like properties. DCs pulsed with PapMV-like particles displaying the lymphocytic choriomeningitis virus (LCMV) p33 immunodominant CTL epitope (PapMV-p33) efficiently process and cross-present the viral epitope to p33-specific transgenic T cells. Importantly, the CTL epitope is also properly processed and presented in vivo, since immunization of p33-specific T-cell receptor transgenic mice with PapMV-p33 induces the activation of large numbers of specific CTLs. C57BL/6 mice immunized with PapMV-p33 VLPs in the absence of adjuvant develop p33-specific effector CTLs that rapidly expand following LCMV challenge and protect vaccinated mice against LCMV infection in a dose-dependent manner. These results demonstrate the efficiency of this novel plant virus-based vaccination platform in inducing DC maturation leading to protective CTL responses.

  19. Inactivated Influenza Vaccine That Provides Rapid, Innate-Immune-System-Mediated Protection and Subsequent Long-Term Adaptive Immunity

    PubMed Central

    Wong, Chinn Yi; Mifsud, Edin J.; Edenborough, Kathryn M.; Sekiya, Toshiki; Tan, Amabel C. L.; Mercuri, Francesca; Rockman, Steve; Chen, Weisan; Turner, Stephen J.; Doherty, Peter C.; Kelso, Anne; Brown, Lorena E.; Jackson, David C.

    2015-01-01

    ABSTRACT The continual threat to global health posed by influenza has led to increased efforts to improve the effectiveness of influenza vaccines for use in epidemics and pandemics. We show in this study that formulation of a low dose of inactivated detergent-split influenza vaccine with a Toll-like receptor 2 (TLR2) agonist-based lipopeptide adjuvant (R4Pam2Cys) provides (i) immediate, antigen-independent immunity mediated by the innate immune system and (ii) significant enhancement of antigen-dependent immunity which exhibits an increased breadth of effector function. Intranasal administration of mice with vaccine formulated with R4Pam2Cys but not vaccine alone provides protection against both homologous and serologically distinct (heterologous) viral strains within a day of administration. Vaccination in the presence of R4Pam2Cys subsequently also induces high levels of systemic IgM, IgG1, and IgG2b antibodies and pulmonary IgA antibodies that inhibit hemagglutination (HA) and neuraminidase (NA) activities of homologous but not heterologous virus. Improved primary virus nucleoprotein (NP)-specific CD8+ T cell responses are also induced by the use of R4Pam2Cys and are associated with robust recall responses to provide heterologous protection. These protective effects are demonstrated in wild-type and antibody-deficient animals but not in those depleted of CD8+ T cells. Using a contact-dependent virus transmission model, we also found that heterologous virus transmission from vaccinated mice to naive mice is significantly reduced. These results demonstrate the potential of adding a TLR2 agonist to an existing seasonal influenza vaccine to improve its utility by inducing immediate short-term nonspecific antiviral protection and also antigen-specific responses to provide homologous and heterologous immunity. PMID:26507227

  20. Schisandrol B protects against acetaminophen-induced hepatotoxicity by inhibition of CYP-mediated bioactivation and regulation of liver regeneration.

    PubMed

    Jiang, Yiming; Fan, Xiaomei; Wang, Ying; Chen, Pan; Zeng, Hang; Tan, Huasen; Gonzalez, Frank J; Huang, Min; Bi, Huichang

    2015-01-01

    Acetaminophen (APAP) overdose is the most frequent cause of drug-induced acute liver failure. Schisandra sphenanthera is a traditional hepato-protective Chinese medicine and Schisandrol B (SolB) is one of its major active constituents. In this study, the protective effect of SolB against APAP-induced acute hepatotoxicity in mice and the involved mechanisms were investigated. Morphological and biochemical assessments clearly demonstrated a protective effect of SolB against APAP-induced liver injury. SolB pretreatment significantly attenuated the increases in alanine aminotransferase and aspartate aminotransferase activity, and prevented elevated hepatic malondialdehyde formation and the depletion of mitochondrial glutathione (GSH) in a dose-dependent manner. SolB also dramatically altered APAP metabolic activation by inhibiting the activities of CYP2E1 and CYP3A11, which was evidenced by significant inhibition of the formation of the oxidized APAP metabolite NAPQI-GSH. A molecular docking model also predicted that SolB had potential to interact with the CYP2E1 and CYP3A4 active sites. In addition, SolB abrogated APAP-induced activation of p53 and p21, and increased expression of liver regeneration and antiapoptotic-related proteins such as cyclin D1 (CCND1), PCNA, and BCL-2. This study demonstrated that SolB exhibited a significant protective effect toward APAP-induced liver injury, potentially through inhibition of CYP-mediated APAP bioactivation and regulation of the p53, p21, CCND1, PCNA, and BCL-2 to promote liver regeneration.

  1. Schisandrol B Protects Against Acetaminophen-Induced Hepatotoxicity by Inhibition of CYP-Mediated Bioactivation and Regulation of Liver Regeneration

    PubMed Central

    Jiang, Yiming; Fan, Xiaomei; Wang, Ying; Chen, Pan; Zeng, Hang; Tan, Huasen; Gonzalez, Frank J.; Bi, Huichang

    2015-01-01

    Acetaminophen (APAP) overdose is the most frequent cause of drug-induced acute liver failure. Schisandra sphenanthera is a traditional hepato-protective Chinese medicine and Schisandrol B (SolB) is one of its major active constituents. In this study, the protective effect of SolB against APAP-induced acute hepatotoxicity in mice and the involved mechanisms were investigated. Morphological and biochemical assessments clearly demonstrated a protective effect of SolB against APAP-induced liver injury. SolB pretreatment significantly attenuated the increases in alanine aminotransferase and aspartate aminotransferase activity, and prevented elevated hepatic malondialdehyde formation and the depletion of mitochondrial glutathione (GSH) in a dose-dependent manner. SolB also dramatically altered APAP metabolic activation by inhibiting the activities of CYP2E1 and CYP3A11, which was evidenced by significant inhibition of the formation of the oxidized APAP metabolite NAPQI–GSH. A molecular docking model also predicted that SolB had potential to interact with the CYP2E1 and CYP3A4 active sites. In addition, SolB abrogated APAP-induced activation of p53 and p21, and increased expression of liver regeneration and antiapoptotic-related proteins such as cyclin D1 (CCND1), PCNA, and BCL-2. This study demonstrated that SolB exhibited a significant protective effect toward APAP-induced liver injury, potentially through inhibition of CYP-mediated APAP bioactivation and regulation of the p53, p21, CCND1, PCNA, and BCL-2 to promote liver regeneration. PMID:25319358

  2. B. subtilis GS67 protects C. elegans from Gram-positive pathogens via fengycin-mediated microbial antagonism.

    PubMed

    Iatsenko, Igor; Yim, Joshua J; Schroeder, Frank C; Sommer, Ralf J

    2014-11-17

    Studies on Caenorhabditis elegans have provided detailed insight into host-pathogen interactions. Usually, the E. coli strain OP50 is used as food source for laboratory studies, but recent work has shown that a variety of bacteria have dramatic effects on C. elegans physiology, including immune responses. However, the mechanisms by which different bacteria impact worm resistance to pathogens are poorly understood. Although pathogen-specific immune priming is often discussed as a mechanism underlying such observations, interspecies microbial antagonism might represent an alternative mode of action. Here, we use several natural Bacillus strains to study their effects on nematode survival upon pathogen challenge. We show that B. subtilis GS67 persists in the C. elegans intestine and increases worm resistance to Gram-positive pathogens, suggesting that direct inhibition of pathogens might be the primary protective mechanism. Indeed, chemical and genetic analyses identified the lipopeptide fengycin as the major inhibitory molecule produced by B. subtilis GS67. Specifically, a fengycin-defective mutant of B. subtilis GS67 lost inhibitory activity against pathogens and was unable to protect C. elegans from infections. Furthermore, we found that purified fengycin cures infected worms in a dose-dependent manner, indicating that it acts as an antibiotic. Our results reveal a molecular mechanism for commensal-mediated C. elegans protection and highlight the importance of interspecies microbial antagonism for the outcome of animal-pathogen interactions. Furthermore, our work strengthens C. elegans as an in vivo model to reveal protective mechanisms of commensal bacteria, including those relevant to mammalian hosts. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. A bipartite operator interacts with a heat shock element to mediate early meiotic induction of Saccharomyces cerevisiae HSP82

    SciTech Connect

    Szent-Gyorgyi, C.

    1995-12-01

    This report seeks to characterize the activation of meiotic gene in terms of cis-acting DNA elements and their associated factors in Saccharomyces cerevisiae. It was found that vegetative repression and meiotic induction depend on interactions of the promoter-proximal heat shock element with a nearby bipartite repression element. The experiments described explore how two different regulatory pathways induce transcription by stimulating a single classical activation element, a nonspecific heat shock element. 81 refs., 10 figs., 1 tab.

  4. Plasma-Mediated Gut Protection After Hemorrhagic Shock is Lessened in Syndecan-1-/- Mice.

    PubMed

    Ban, Kechen; Peng, Zhanglong; Pati, Shibani; Witkov, Richard B; Park, Pyong Woo; Kozar, Rosemary A

    2015-11-01

    We have shown in a rodent model of hemorrhagic shock (HS) that fresh frozen plasma (FFP) reduces lung inflammation and injury that are correlated with restitution of syndecan-1. As the gut is believed to contribute to distant organ injury and inflammation after shock, the current study sought to determine if the protective effects of plasma would extend to the gut and to elucidate the contribution of syndecan-1 to this protective effect. We also examined the potential role of TNFα, and a disintegrin and metalloproteinase (ADAM)-17, both intestinal sheddases of syndecan-1. Wild-type (WT) and syndecan-1 (KO) mice were subjected to HS followed by resuscitation with lactated Ringer's (LR) or FFP and compared with shock alone and shams. Small bowel and blood were obtained after 3  h for analysis of mucosal injury and inflammation and TNFα and ADAM-17 protein expression and activity. After HS, gut injury and inflammation were significantly increased compared with shams. Resuscitation with LR decreased both injury and inflammation that were further lessened by FFP. KO mice displayed worsened gut injury and inflammation after HS compared with WT mice, and LR and FFP equivalently inhibited injury and inflammation. Both systemic and intestinal TNFα and ADAM-17 followed similar trends, with increases after HS, reduction by LR, and a further decrease by FFP in WT but not KO mice. In conclusion, FFP decreased gut injury and inflammation after hemorrhagic shock, an effect that was abrogated in syndecan-1 mice. Plasma also decreased TNFα and ADAM-17, representing a potential mechanistic link to its protection via syndecan-1.

  5. Mechanisms of PEDF-mediated protection against reactive oxygen species damage in diabetic retinopathy and neuropathy.

    PubMed

    Elahy, Mina; Baindur-Hudson, Swati; Cruzat, Vinicius F; Newsholme, Philip; Dass, Crispin R

    2014-09-01

    Pigment epithelium-derived factor (PEDF) is a pluripotent glycoprotein belonging to the serpin family. PEDF can stimulate several physiological processes such as angiogenesis, cell proliferation, and survival. Oxidative stress plays an important role in the occurrence of diabetic retinopathy (DR), which is the major cause of blindness in young diabetic adults. PEDF plays a protective role in DR and there is accumulating evidence of the neuroprotective effect of PEDF. In this paper, we review the role of PEDF and the mechanisms involved in its antioxidative, anti-inflammatory, and neuroprotective properties.

  6. Phospholipase A2 inhibitors protect against prion and Aβ mediated synapse degeneration

    PubMed Central

    2010-01-01

    Background An early event in the neuropathology of prion and Alzheimer's diseases is the loss of synapses and a corresponding reduction in the level of synaptophysin, a pre-synaptic membrane protein essential for neurotransmission. The molecular mechanisms involved in synapse degeneration in these diseases are poorly understood. In this study the process of synapse degeneration was investigated by measuring the synaptophysin content of cultured neurones incubated with the prion derived peptide (PrP82-146) or with Aβ1-42, a peptide thought to trigger pathogenesis in Alzheimer's disease. A pharmacological approach was used to screen cell signalling pathways involved in synapse degeneration. Results Pre-treatment with phospholipase A2 inhibitors (AACOCF3, MAFP and aristolochic acids) protected against synapse degeneration in cultured cortical and hippocampal neurones incubated with PrP82-146 or Aβ1-42. Synapse degeneration was also observed following the addition of a specific phospholipase A2 activating peptide (PLAP) and the addition of PrP82-146 or Aβ1-42 activated cytoplasmic phospholipase A2 within synapses. Activation of phospholipase A2 is the first step in the generation of platelet-activating factor (PAF) and PAF receptor antagonists (ginkgolide B, Hexa-PAF and CV6029) protected against synapse degeneration induced by PrP82-146, Aβ1-42 and PLAP. PAF facilitated the production of prostaglandin E2, which also caused synapse degeneration and pre-treatment with the prostanoid E receptor antagonist AH13205 protected against PrP82-146, Aβ1-42 and PAF induced synapse degeneration. Conclusions Our results are consistent with the hypothesis that PrP82-146 and Aβ1-42trigger abnormal activation of cytoplasmic phospholipase A2 resident within synapses, resulting in elevated levels of PAF and prostaglandin E2that cause synapse degeneration. Inhibitors of this pathway that can cross the blood brain barrier may protect against the synapse degeneration seen during

  7. The Protective Role of Antioxidants in the Defence against ROS/RNS-Mediated Environmental Pollution

    PubMed Central

    Poljšak, Borut; Fink, Rok

    2014-01-01

    Overproduction of reactive oxygen and nitrogen species can result from exposure to environmental pollutants, such as ionising and nonionising radiation, ultraviolet radiation, elevated concentrations of ozone, nitrogen oxides, sulphur dioxide, cigarette smoke, asbestos, particulate matter, pesticides, dioxins and furans, polycyclic aromatic hydrocarbons, and many other compounds present in the environment. It appears that increased oxidative/nitrosative stress is often neglected mechanism by which environmental pollutants affect human health. Oxidation of and oxidative damage to cellular components and biomolecules have been suggested to be involved in the aetiology of several chronic diseases, including cancer, cardiovascular disease, cataracts, age-related macular degeneration, and aging. Several studies have demonstrated that the human body can alleviate oxidative stress using exogenous antioxidants. However, not all dietary antioxidant supplements display protective effects, for example, β-carotene for lung cancer prevention in smokers or tocopherols for photooxidative stress. In this review, we explore the increases in oxidative stress caused by exposure to environmental pollutants and the protective effects of antioxidants. PMID:25140198

  8. Wolbachia-mediated protection against viruses in the invasive pest Drosophila suzukii.

    PubMed

    Cattel, J; Martinez, J; Jiggins, F; Mouton, L; Gibert, P

    2016-10-01

    The maternally inherited bacterium Wolbachia is well known for spreading in natural populations by manipulating the reproduction of its arthropod hosts, but can also have mutualist effects that increase host fitness. In mosquitoes and Drosophila some Wolbachia strains can lead to an increase in survival of virus-infected insects, and in most cases this is associated with reduced accumulation of the virus in host tissues. We investigated if the Wolbachia strain wSuz, which naturally infects Drosophila suzukii, is able to confer protection against Drosophila C virus and Flock House virus in different host genetic backgrounds. We found that this strain can increase host survival upon infection with these two viruses. In some cases this effect was associated with lower viral titres, suggesting that it confers resistance to the viruses rather than allowing the flies to tolerate infection. Our results indicate that, in D. suzukii, the antiviral protection provided by Wolbachia is not correlated to its density as found in other Drosophila species. This study demonstrates a phenotypic effect induced by wSuz on its native host which could explain its maintenance in natural populations of D. suzukii. © 2016 The Royal Entomological Society.

  9. The role of lactoferrin binding protein B in mediating protection against human lactoferricin.

    PubMed

    Morgenthau, Ari; Livingstone, Margaret; Adamiak, Paul; Schryvers, Anthony B

    2012-06-01

    Bacteria that inhabit the mucosal surfaces of the respiratory and genitourinary tracts of mammals encounter an iron-deficient environment because of iron sequestration by the host iron-binding proteins transferrin and lactoferrin. Lactoferrin is also present in high concentrations at sites of inflammation where the cationic, antimicrobial peptide lactoferricin is produced by proteolysis of lactoferrin. Several Gram-negative pathogens express a lactoferrin receptor that enables the bacteria to use lactoferrin as an iron source. The receptor is composed of an integral membrane protein, lactoferrin binding protein A (LbpA), and a membrane-bound lipoprotein, lactoferrin binding protein B (LbpB). LbpA is essential for growth with lactoferrin as the sole iron source, whereas the role of LbpB in iron acquisition is not yet known. In this study, we demonstrate that LbpB from 2 different species is capable of providing protection against the killing activity of a human lactoferrin-derived peptide. We investigated the prevalence of lactoferrin receptors in bacteria and examined their sequence diversity. We propose that the protection against the cationic antimicrobial human lactoferrin-derived peptide is associated with clusters of negatively charged amino acids in the C-terminal lobe of LbpB that is a common feature of this protein.

  10. Immunological mechanisms involved in probiotic-mediated protection against Citrobacter rodentium-induced colitis.

    PubMed

    Jiang, Y; Yang, G; Meng, F; Yang, W; Hu, J; Ye, L; Shi, C; Wang, C

    2016-06-01

    Inflammatory bowel disease is a group of chronic, incurable inflammatory disorders of the gastrointestinal tract that cause severe diarrhoea, intestinal inflammation, pain, fatigue and weight loss. In this study, we first developed a model of Citrobacter rodentium-induced colitis and then evaluated the protective effects of selected probiotics on inflammation. The results showed that administration of a combination of probiotics including Lactobacillus rhamnosus ATCC 53103, Lactobacillus acidophilus ATCC 4356 and Lactobacillus plantarum A significantly increased the production of CD11c(+) dendritic cells in the spleen (3.62% vs phosphate buffered saline (PBS)-treated control, P<0.01) and mesenteric lymph nodes (MLNs). In addition, the presence of probiotics significantly up-regulated the development of CD4(+)/CD25(+)/Foxp3(+) regulatory T cells in MLNs by approximately 2.07% compared to the effect observed in the PBS-treated control (P<0.01) and down-regulated the expression of inflammatory cytokines, including interleukin-17, tumour necrosis factor-α and interferon-γ, by 0.11, 0.11 and 0.15%, respectively, compared to the effect observed in the PBS-treated control (P<0.01).These effects conferred protection against colitis, as shown by histopathological analyses.

  11. The biosynthesis of ascorbate protects isolated rat hepatocytes from cumene hydroperoxide-mediated oxidative stress.

    PubMed

    Chan, Tom S; Shangari, Nandita; Wilson, John X; Chan, Helen; Butterworth, Roger F; O'Brien, Peter J

    2005-04-01

    Most animals synthesize ascorbate. It is an essential enzymatic cofactor for the synthesis of a variety of biological molecules and also a powerful antioxidant. There is, however, little direct evidence supporting an antioxidant role for endogenously produced ascorbate. Recently, we demonstrated that incubation of rat hepatocytes with 1-bromoheptane or phorone simultaneously depleted glutathione (GSH) and triggered rapid ascorbate synthesis. The present study investigates the hypothesis that endogenous ascorbate synthesis can confer protection against oxidative stress. Rat and guinea pig hepatocytes were depleted of GSH with 1-bromoheptane and subsequently treated with the oxidative stressor cumene hydroperoxide (CHP) in the presence or absence of the ascorbate synthesis inhibitor sorbinil. In rat hepatocytes, ascorbate content increased linearly (from 15.1 to 35.8 nmol/10(6) cells) over a 105-min incubation. Prior depletion of GSH increased CHP-induced cellular reactive oxygen species (ROS) production, lipid peroxidation, and cell death in rat and guinea pig hepatocytes. Inhibiting ascorbate synthesis, however, further elevated ROS production (2-fold), lipid peroxidation (1.5-fold), and cell death (2-fold) in rat hepatocytes only. This is the first time that endogenous ascorbate synthesis has been shown to decrease cellular susceptibility to oxidative stress. Protection by endogenously produced ascorbate may therefore need to be addressed when extrapolating data to humans from experiments using rodents capable of synthesizing ascorbate.

  12. Selective protection of the cerebellum against intracerebroventricular LPS is mediated by local melatonin synthesis.

    PubMed

    Pinato, Luciana; da Silveira Cruz-Machado, Sanseray; Franco, Daiane G; Campos, Leila M G; Cecon, Erika; Fernandes, Pedro A C M; Bittencourt, Jackson C; Markus, Regina P

    2015-03-01

    Although melatonin is mainly produced by the pineal gland, an increasing number of extra-pineal sites of melatonin synthesis have been described. We previously demonstrated the existence of bidirectional communication between the pineal gland and the immune system that drives a switch in melatonin production from the pineal gland to peripheral organs during the mounting of an innate immune response. In the present study, we show that acute neuroinflammation induced by lipopolysaccharide (LPS) injected directly into the lateral ventricles of adult rats reduces the nocturnal peak of melatonin in the plasma and induces its synthesis in the cerebellum, though not in the cortex or hippocampus. This increase in cerebellar melatonin content requires the activation of nuclear factor kappa B (NF-κB), which positively regulates the expression of the key enzyme for melatonin synthesis, arylalkylamine N-acetyltransferase (AA-NAT). Interestingly, LPS treatment led to neuronal death in the hippocampus and cortex, but not in the cerebellum. This privileged protection of cerebellar cells was abrogated when G-protein-coupled melatonin receptors were blocked by the melatonin antagonist luzindole, suggesting that the local production of melatonin protects cerebellar neurons from LPS toxicity. This is the first demonstration of a switch between pineal and extra-pineal melatonin production in the central nervous system following a neuroinflammatory response. These results have direct implications concerning the differential susceptibility of specific brain areas to neuronal death.

  13. Genotype specificity among hosts, pathogens, and beneficial microbes influences the strength of symbiont‐mediated protection

    PubMed Central

    Parker, Benjamin J.; Hrček, Jan; McLean, Ailsa H. C.; Godfray, H. Charles J.

    2017-01-01

    The microbial symbionts of eukaryotes influence disease resistance in many host‐parasite systems. Symbionts show substantial variation in both genotype and phenotype, but it is unclear how natural selection maintains this variation. It is also unknown whether variable symbiont genotypes show specificity with the genotypes of hosts or parasites in natural populations. Genotype by genotype interactions are a necessary condition for coevolution between interacting species. Uncovering the patterns of genetic specificity among hosts, symbionts, and parasites is therefore critical for determining the role that symbionts play in host‐parasite coevolution. Here, we show that the strength of protection conferred against a fungal pathogen by a vertically transmitted symbiont of an aphid is influenced by both host‐symbiont and symbiont‐pathogen genotype by genotype interactions. Further, we show that certain symbiont phylogenetic clades have evolved to provide stronger protection against particular pathogen genotypes. However, we found no evidence of reciprocal adaptation of co‐occurring host and symbiont lineages. Our results suggest that genetic variation among symbiont strains may be maintained by antagonistic coevolution with their host and/or their host's parasites. PMID:28252804

  14. CD11b is protective in complement-mediated immune complex glomerulonephritis

    PubMed Central

    Alexander, Jessy J; Chaves, Lee D; Chang, Anthony; Jacob, Alexander; Ritchie, Maria; Quigg, Richard J

    2015-01-01

    In chronic serum sickness, glomerular immune complexes form, yet C57BL/6 mice do not develop glomerulonephritis unless complement factor H (CfH) is absent, indicating the relevance of complement regulation. Complement receptor 3 (CD11b) and Fcγ receptors on leukocytes, and CfH on platelets, can bind immune complexes. Here we induced immune complex–mediated glomerulonephritis in CfH−/− mice chimeric for wild-type, CfH−/−, CD11b−/−, or FcRγ−/− bone marrow stem cells. Glomerulonephritis was worse in CD11b−/− chimeras compared with all others, whereas disease in FcRγ−/− and wild-type chimeras was comparable. Disease tracked strongly with humoral immune responses, but not glomerular immune complex deposits. Interstitial inflammation with M1 macrophages strongly correlated with glomerulonephritis scores. CD11b−/− chimeras had significantly more M1 macrophages and CD4+ T cells. The renal dendritic cell populations originating from bone marrow–derived CD11c+ cells were similar in all experimental groups. CD11b+ cells bearing colony-stimulating factor 1 receptor were present in kidneys, including CD11b−/− chimeras; these cells correlated negatively with glomerulonephritis scores. Thus, experimental immune complex–mediated glomerulonephritis is associated with accumulation of M1 macrophages and CD4+ T cells in kidneys and functional renal insufficiency. Hence, CD11b on mononuclear cells is instrumental in generating an anti-inflammatory response in the inflamed kidney. PMID:25565310

  15. SGLT-1-mediated glucose uptake protects human intestinal epithelial cells against Giardia duodenalis-induced apoptosis.

    PubMed

    Yu, Linda C H; Huang, Ching-Ying; Kuo, Wei-Ting; Sayer, Heather; Turner, Jerrold R; Buret, Andre G

    2008-07-01

    Infection with Giardia duodenalis is one of the most common causes of waterborne diarrheal disease worldwide. Mechanisms of pathogenesis and host response in giardiasis remain incompletely understood. Previous studies have shown that exposure to G. duodenalis products induce apoptosis in enterocytes. We recently discovered that sodium-dependent glucose cotransporter (SGLT)-1-mediated glucose uptake modulates enterocytic cell death induced by bacterial lipopolysaccharide. The aim of this study was to examine whether enhanced epithelial SGLT-1 activity may constitute a novel mechanism of host defense against G. duodenalis-induced apoptosis. SGLT-1-transfected Caco-2 cells were exposed to G. duodenalis products in low (5mM) or high (25mM) glucose media. In low glucose environments, G. duodenalis-induced caspase-3 activation and DNA fragmentation in these cells. These apoptotic phenomena were abolished in the presence of high glucose. A soluble proteolytic fraction of G. duodenalis was found to upregulate SGLT-1-mediated glucose uptake in a dose- and time-dependent manner, in association with increased apical SGLT-1 expression on epithelial cells. Kinetic analysis showed that this phenomenon resulted from an increase in the maximal rate of sugar transport (V(max)) by SGLT-1, with no change in the affinity constant (K(m)). The addition of phloridzin (a competitive inhibitor for glucose binding to SGLT-1) abolished the anti-apoptotic effects exerted by high glucose. Together, the findings indicate that SGLT-1-dependent glucose uptake may represent a novel epithelial cell rescue mechanism against G. duodenalis-induced apoptosis.

  16. Ethanol Extract of Cirsium japonicum var. ussuriense Kitamura Exhibits the Activation of Nuclear Factor Erythroid 2-Related Factor 2-dependent Antioxidant Response Element and Protects Human Keratinocyte HaCaT Cells Against Oxidative DNA Damage

    PubMed Central

    Yoo, Ok-Kyung; Choi, Bu Young; Park, Jin-Oh; Lee, Ji-Won; Park, Byoung-Kwon; Joo, Chul Gue; Heo, Hyo-Jung; Keum, Young-Sam

    2016-01-01

    Keratinocytes are constantly exposed to extracellular insults, such as ultraviolet B, toxic chemicals and mechanical stress, all of which can facilitate the aging of keratinocytes via the generation of intracellular reactive oxygen species (ROS). Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that plays a critical role in protecting keratinocytes against oxidants and xenobiotics by binding to the antioxidant response element (ARE), a cis-acting element existing in the promoter of most phase II cytoprotective genes. In the present study, we have attempted to find novel ethanol extract(s) of indigenous plants of Jeju island, Korea that can activate the Nrf2/ARE-dependent gene expression in human keratinocyte HaCaT cells. As a result, we identified that ethanol extract of Cirsium japonicum var. ussuriense Kitamura (ECJUK) elicited strong stimulatory effect on the ARE-dependent gene expression. Supporting this observation, we found that ECJUK induced the expression of Nrf2, hemoxygenase-1, and NAD(P)H:quinone oxidoreductase-1 and this event was correlated with Akt1 phosphorylation. We also found that ECJUK increased the intracellular reduced glutathione level and suppressed 12-O-tetradecanoylphorbol acetate-induced 8-hydroxyguanosine formation without affecting the overall viability. Collectively, our results provide evidence that ECJUK can protect against oxidative stress-mediated damages through the activation of Nrf2/ARE-dependent phase II cytoprotective gene expression. PMID:27051652

  17. Akt1 promotes stimuli-induced endothelial-barrier protection through FoxO-mediated tight-junction protein turnover.

    PubMed

    Gao, Fei; Artham, Sandeep; Sabbineni, Harika; Al-Azayzih, Ahmad; Peng, Xiao-Ding; Hay, Nissim; Adams, Ralf H; Byzova, Tatiana V; Somanath, Payaningal R

    2016-10-01

    Vascular permeability regulated by the vascular endothelial growth factor (VEGF) through endothelial-barrier junctions is essential for inflammation. Mechanisms regulating vascular permeability remain elusive. Although 'Akt' and 'Src' have been implicated in the endothelial-barrier regulation, it is puzzling how both agents that protect and disrupt the endothelial-barrier activate these kinases to reciprocally regulate vascular permeability. To delineate the role of Akt1 in endothelial-barrier regulation, we created endothelial-specific, tamoxifen-inducible Akt1 knockout mice and stable ShRNA-mediated Akt1 knockdown in human microvascular endothelial cells. Akt1 loss leads to decreased basal and angiopoietin1-induced endothelial-barrier resistance, and enhanced VEGF-induced endothelial-barrier breakdown. Endothelial Akt1 deficiency resulted in enhanced VEGF-induced vascular leakage in mice ears, which was rescued upon re-expression with Adeno-myrAkt1. Furthermore, co-treatment with angiopoietin1 reversed VEGF-induced vascular leakage in an Akt1-dependent manner. Mechanistically, our study revealed that while VEGF-induced short-term vascular permeability is independent of Akt1, its recovery is reliant on Akt1 and FoxO-mediated claudin expression. Pharmacological inhibition of FoxO transcription factors rescued the defective endothelial barrier due to Akt1 deficiency. Here we provide novel insights on the endothelial-barrier protective role of VEGF in the long term and the importance of Akt1-FoxO signaling on tight-junction stabilization and prevention of vascular leakage through claudin expression.

  18. Mediating delta-opioid-initiated heart protection via the beta2-adrenergic receptor: role of the intrinsic cardiac adrenergic cell.

    PubMed

    Huang, Ming-He; Wang, Hui-Qun; Roeske, William R; Birnbaum, Yochai; Wu, Yewen; Yang, Ning-Ping; Lin, Yu; Ye, Yumei; McAdoo, David J; Hughes, Michael G; Lick, Scott D; Boor, Paul J; Lui, Charles Y; Uretsky, Barry F

    2007-07-01

    Stimulation of cardiac beta(2)-adrenergic receptor (beta(2)-AR) or delta-opioid receptor (DOR) exerts a similar degree of cardioprotection against myocardial ischemia in experimental models. We hypothesized that delta-opioid-initiated cardioprotection is mediated by the intrinsic cardiac adrenergic (ICA) cell via enhanced epinephrine release. Using immunohistochemical and in situ hybridization methods, we detected in situ tyrosine hydroxylase (TH) mRNA and TH immunoreactivity that was colocalized with DOR immunoreactivity in ICA cells in human and rat hearts. Western blot analysis detected DOR protein in ICA cells isolated from rat ventricular myocytes. The physiology of DOR expression was examined by determining changes of cytosolic Ca(2+) concentration ([Ca(2+)](i)) transients in isolated rat ICA cells using fluorescence spectrophotometry. Exposing the selective delta-opioid agonist D-[Pen(2,5)]enkephalin (DPDPE) to ICA cells increased [Ca(2+)](i) transients in a concentration-dependent manner. Such an effect was abolished by the Ca(2+) channel blocker nifedipine. HPLC-electrochemical detection demonstrated a 2.4-fold increase in epinephrine release from ICA cells following DPDPE application. The significance of the ICA cell and its epinephrine release in delta-opioid-initiated cardioprotection was demonstrated in the rat myocardial infarction model and ICA cell-ventricular myocyte coculture. DPDPE administered before coronary artery occlusion or simulated ischemia-reperfusion reduced left ventricular infarct size by 54 +/- 15% or myocyte death by 26 +/- 4%, respectively. beta(2)-AR blockade markedly attenuated delta-opioid-initiated infarct size-limiting effect and abolished delta-opioid-initiated myocyte survival protection in rat ICA cell-myocyte coculture. Furthermore, delta-opioid agonist exerted no myocyte survival protection in the absence of cocultured ICA cells during ischemia-reperfusion. We conclude that delta-opioid-initiated myocardial infarct size

  19. Protective action of nipradilol mediated through S-nitrosylation of Keap1 and HO-1 induction in retinal ganglion cells.

    PubMed

    Koriyama, Yoshiki; Kamiya, Marie; Takadera, Tsuneo; Arai, Kunizo; Sugitani, Kayo; Ogai, Kazuhiro; Kato, Satoru

    2012-12-01

    Nipradilol (Nip), which has α1- and β-adrenoceptor antagonist and nitric oxide (NO)-donating properties, has clinically been used as an anti-glaucomatous agent in Japan. NO mediates cellular signaling pathways that regulate physiological functions. The major signaling mechanisms mediated by NO are cGMP-dependent signaling and protein S-nitrosylation-dependent signalings. Nip has been described as having neuroprotective effects through cGMP-dependent pathway in retinal ganglion cells (RGCs). However, the effect seems to be partial. On the other hand, whether Nip can prevent cell death through S-nitrosylation is not yet clarified. In this study, we therefore focused on the neuroprotective mechanism of Nip through S-nitrosylation. Nip showed a dramatic neuroprotective effect against oxidative stress-induced death of RGC-5 cells. However, denitro-nipradilol, which does not have NO-donating properties, was not protective against oxidative stress. Furthermore, an NO scavenger significantly reversed the protective action of Nip against oxidative stress. In addition, we demonstrated that α1- or β-adrenoceptor antagonists (prazosin or timolol) did not show any neuroprotective effect against oxidative stress in RGC-5 cells. We also demonstrated that Nip induced the expression of the NO-dependent antioxidant enzyme, heme oxygenase-1 (HO-1). S-nitrosylation of Kelch-like ECH-associated protein by Nip was shown to contribute to the translocation of NF-E2-related factor 2 to the nucleus, and triggered transcriptional activation of HO-1. Furthermore, RGC death and levels of 4-hydroxy-2-nonenal (4HNE) were increased after optic nerve injury in vivo. Pretreatment with Nip significantly suppressed RGC death and accumulation of 4HNE after injury through an HO-1 activity-dependent mechanism. These data demonstrate a novel neuroprotective action of Nip against oxidative stress-induced RGC death in vitro and in vivo.

  20. Epoxypukalide Induces Proliferation and Protects against Cytokine-Mediated Apoptosis in Primary Cultures of Pancreatic β-Cells

    PubMed Central

    López-Acosta, José Francisco; Moreno-Amador, José Luis; Jiménez-Palomares, Margarita; Díaz-Marrero, Ana R.; Cueto, Mercedes; Perdomo, Germán; Cózar-Castellano, Irene

    2013-01-01

    There is an urgency to find new treatments for the devastating epidemic of diabetes. Pancreatic β-cells viability and function are impaired in the two most common forms of diabetes, type 1 and type 2. Regeneration of pancreatic β-cells has been proposed as a potential therapy for diabetes. In a preliminary study, we screened a collection of marine products for β-cell proliferation. One unique compound (epoxypukalide) showed capability to induce β-cell replication in the cell line INS1 832/13 and in primary rat cell cultures. Epoxypukalide was used to study β-cell proliferation by [3H]thymidine incorporation and BrdU incorporation followed by BrdU/insulin staining in primary cultures of rat islets. AKT and ERK1/2 signalling pathways were analyzed. Cell cycle activators, cyclin D2 and cyclin E, were detected by western-blot. Apoptosis was studied by TUNEL and cleaved caspase 3. β-cell function was measured by glucose-stimulated insulin secretion. Epoxypukalide induced 2.5-fold increase in β-cell proliferation; this effect was mediated by activation of ERK1/2 signalling pathway and upregulation of the cell cycle activators, cyclin D2 and cyclin E. Interestingly, epoxypukalide showed protection from basal (40% lower versus control) and cytokine-induced apoptosis (80% lower versus control). Finally, epoxypukalide did not impair β-cell function when measured by glucose-stimulated insulin secretion. In conclusion, epoxypukalide induces β-cell proliferation and protects against basal and cytokine-mediated β-cell death in primary cultures of rat islets. These findings may be translated into new treatments for diabetes. PMID:23300997

  1. Protective effect of an egg yolk-derived immunoglobulin (IgY) against Prevotella intermedia-mediated gingivitis.

    PubMed

    Hou, Y-Y; Zhen, Y-H; Wang, D; Zhu, J; Sun, D-X; Liu, X-T; Wang, H-X; Liu, Y; Long, Y-Y; Shu, X-H

    2014-04-01

    To investigate the effects of an egg yolk-derived immunoglobulin (IgY) specific to Prevotella intermedia in vitro and in vivo. An IgY specific to P. intermedia was produced by immunizing hens with formaldehyde-inactivated P. intermedia and showed high titres when subjected to an ELISA. The obtained IgY inhibited the growth of P. intermedia in a dose-dependent manner at concentrations from 1 to 20 mg ml(-1) in Center for Disease Control and Prevention liquid medium. Forty rats were challenged with P. intermedia on gingivae and then randomly divided into four groups, which were syringed respectively with phosphate-buffered saline, 1 mg ml(-1) of tinidazole, 20 mg ml(-1) of nonspecific IgY and 20 mg ml(-1) of the IgY specific to P. intermedia at a dosage of 300 μl per day. Gingival index (GI), plaque index (PI), bleeding on probing (BOP), counts of white blood cell (WBC) and histopathological slide of the gums were measured after treatment for 15 days. The gingivitis rats treated with the IgY specific to P. intermedia showed significantly decreased GI, PI, BOP and WBC (P < 0·05). Gum histopathology of the treated rats demonstrated a superior protective effect of the specific IgY on P. intermedia-mediated gingivitis. A new immunoglobulin specific to P. intermedia was developed from egg yolk. This specific IgY can dose-dependently inhibit the growth of P. intermedia and protect rats from gingivitis induced by P. intermedia. The new IgY has potential for the treatment of P. intermedia-mediated gingivitis. © 2013 The Society for Applied Microbiology.

  2. Mulberrofuran G Protects Ischemic Injury-induced Cell Death via Inhibition of NOX4-mediated ROS Generation and ER Stress.

    PubMed

    Hong, Sungeun; Kwon, Jaeyoung; Kim, Dong-Woo; Lee, Hak Ju; Lee, Dongho; Mar, Woongchon

    2017-02-01

    The aim of this study was to investigate the neuroprotective effect of mulberrofuran G (MG) in in vitro and in vivo models of cerebral ischemia. MG was isolated from the root bark of Morus bombycis. MG inhibited nicotinamide adenine dinucleotide phosphate oxidase (NOX) enzyme activity and oxygen-glucose deprivation/reoxygenation (OGD/R)-induced NOX4 protein expression in SH-SY5Y cells. MG inhibited the expression of activated caspase-3 and caspase-9 and cleaved poly adenine dinucleotide phosphate-ribose polymerase in OGD/R-induced SH-SY5Y cells. In addition, MG protected OGD/R-induced neuronal cell death and inhibited OGD/R-induced reactive oxygen species generation in SH-SY5Y cells. In in vivo model, MG-treated groups (0.2, 1, and 5 mg/kg) reduced the infarct volume in middle cerebral artery occlusion/reperfusion-induced ischemic rats. The MG-treated groups also reduced NOX4 protein expression in middle cerebral artery occlusion/reperfusion-induced ischemic rats. Furthermore, protein expression of 78-kDa glucose-regulated protein/binding immunoglobulin protein, phosphorylated IRE1α, X-box-binding protein 1, and cytosine enhancer binding protein homologous protein, mediators of endoplasmic reticulum stress, were inhibited in MG-treated groups. Taken together, MG showed protective effect in in vitro and in vivo models of cerebral ischemia through inhibition of NOX4-mediated reactive oxygen species generation and endoplasmic reticulum stress. This finding will give an insight that inhibition of NOX enzyme activity and NOX4 protein expression could be a new potential therapeutic strategy for cerebral ischemia. Copyright © 2016 John Wiley & Sons, Ltd.

  3. Iron-Mediated Lysosomal Membrane Permeabilization in Ethanol-Induced Hepatic Oxidative Damage and Apoptosis: Protective Effects of Quercetin.

    PubMed

    Li, Yanyan; Chen, Man; Xu, Yanyan; Yu, Xiao; Xiong, Ting; Du, Min; Sun, Jian; Liu, Liegang; Tang, Yuhan; Yao, Ping

    2016-01-01

    Iron, in its free ferrous states, can catalyze Fenton reaction to produce OH∙, which is recognized as a crucial role in the pathogenesis of alcoholic liver diseases (ALD). As a result of continuous decomposition of iron-containing compounds, lysosomes contain a pool of redox-active iron. To investigate the important role of intralysosomal iron in alcoholic liver injury and the potential protection of quercetin, male C57BL/6J mice fed by Lieber De Carli diets containing ethanol (30% of total calories) were cotreated by quercetin or deferoxamine (DFO) for 15 weeks and ethanol-incubated mice primary hepatocytes were pretreated with FeCl3, DFO, and bafilomycin A1 at their optimal concentrations and exposure times. Chronic ethanol consumption caused an evident increase in lysosomal redox-active iron accompanying sustained oxidative damage. Iron-mediated ROS could trigger lysosomal membrane permeabilization (LMP) and subsequent mitochondria apoptosis. The hepatotoxicity was attenuated by reducing lysosomal iron while being exacerbated by escalating lysosomal iron. Quercetin substantially alleviated the alcoholic liver oxidative damage and apoptosis by decreasing lysosome iron and ameliorating iron-mediated LMP, which provided a new prospective of the use of quercetin against ALD.

  4. Iron-Mediated Lysosomal Membrane Permeabilization in Ethanol-Induced Hepatic Oxidative Damage and Apoptosis: Protective Effects of Quercetin

    PubMed Central

    Li, Yanyan; Chen, Man; Xu, Yanyan; Yu, Xiao; Xiong, Ting; Du, Min; Sun, Jian; Liu, Liegang; Tang, Yuhan; Yao, Ping

    2016-01-01

    Iron, in its free ferrous states, can catalyze Fenton reaction to produce OH∙, which is recognized as a crucial role in the pathogenesis of alcoholic liver diseases (ALD). As a result of continuous decomposition of iron-containing compounds, lysosomes contain a pool of redox-active iron. To investigate the important role of intralysosomal iron in alcoholic liver injury and the potential protection of quercetin, male C57BL/6J mice fed by Lieber De Carli diets containing ethanol (30% of total calories) were cotreated by quercetin or deferoxamine (DFO) for 15 weeks and ethanol-incubated mice primary hepatocytes were pretreated with FeCl3, DFO, and bafilomycin A1 at their optimal concentrations and exposure times. Chronic ethanol consumption caused an evident increase in lysosomal redox-active iron accompanying sustained oxidative damage. Iron-mediated ROS could trigger lysosomal membrane permeabilization (LMP) and subsequent mitochondria apoptosis. The hepatotoxicity was attenuated by reducing lysosomal iron while being exacerbated by escalating lysosomal iron. Quercetin substantially alleviated the alcoholic liver oxidative damage and apoptosis by decreasing lysosome iron and ameliorating iron-mediated LMP, which provided a new prospective of the use of quercetin against ALD. PMID:27057276

  5. Stearoyl-CoA Desaturase-1 Protects Cells against Lipotoxicity-Mediated Apoptosis in Proximal Tubular Cells

    PubMed Central

    Iwai, Tamaki; Kume, Shinji; Chin-Kanasaki, Masami; Kuwagata, Shogo; Araki, Hisazumi; Takeda, Naoko; Sugaya, Takeshi; Uzu, Takashi; Maegawa, Hiroshi; Araki, Shin-ichi

    2016-01-01

    Saturated fatty acid (SFA)-related lipotoxicity is a pathogenesis of diabetes-related renal proximal tubular epithelial cell (PTEC) damage, closely associated with a progressive decline in renal function. This study was designed to identify a free fatty acid (FFA) metabolism-related enzyme that can protect PTECs from SFA-related lipotoxicity. Among several enzymes involved in FFA metabolism, we identified stearoyl-CoA desaturase-1 (SCD1), whose expression level significantly decreased in the kidneys of high-fat diet (HFD)-induced diabetic mice, compared with non-diabetic mice. SCD1 is an enzyme that desaturates SFAs, converting them to monounsaturated fatty acids (MUFAs), leading to the formation of neutral lipid droplets. In culture, retrovirus-mediated overexpression of SCD1 or MUFA treatment significantly ameliorated SFA-induced apoptosis in PTECs by enhancing intracellular lipid droplet formation. In contrast, siRNA against SCD1 exacerbated the apoptosis. Both overexpression of SCD1 and MUFA treatment reduced SFA-induced apoptosis via reducing endoplasmic reticulum stress in cultured PTECs. Thus, HFD-induced decrease in renal SCD1 expression may play a pathogenic role in lipotoxicity-induced renal injury, and enhancing SCD1-mediated desaturation of SFA and subsequent formation of neutral lipid droplets may become a promising therapeutic target to reduce SFA-induced lipotoxicity. The present study provides a novel insight into lipotoxicity in the pathogenesis of diabetic nephropathy. PMID:27834856

  6. Fixed drug eruption: the dark side of activation of intraepidermal CD8+ T cells uniquely specialized to mediate protective immunity.

    PubMed

    Shiohara, Tetsuo; Mizukawa, Yoshiko

    2012-01-01

    Fixed drug eruption (FDE) is generally regarded as representing the mild end of drug-induced dermatitis, but the clinical importance of recognizing this disease as an abortive, localized variant of toxic epidermal necrolysis has received increasing attention in recent years. FDE often presents with a wide spectrum of clinical manifestations indistinguishable from those of other skin diseases, such as erythema multiforme, Stevens-Johnson syndrome /toxic epidermal necrolysis, cellulitis, paronychia, lichen planus, and parapsoriasis en plaques. These unusual forms of FDE are likely to be overlooked unless the possibility of a drug etiology is routinely considered in the differential diagnosis of any patient with these diseases. Clinical awareness and recognition of these unique forms are essential for avoiding a misdiagnosis. Intraepidermal CD8+ T cells resident in the FDE lesions that have the capacity to rapidly produce large amounts of IFN-γ are likely to have a key role in mediating localized epidermal injury, while they may represent a T cell subset uniquely specialized to mediate protective immunity against various pathogens. Copyright © 2012 S. Karger AG, Basel.

  7. CD98hc (SLC3A2) Loss Protects Against Ras-Driven Tumorigenesis by Modulating Integrin-Mediated Mechanotransduction

    PubMed Central

    Estrach, Soline; Lee, Sin-Ae; Boulter, Etienne; Pisano, Sabrina; Errante, Aurélia; Tissot, Floriane S.; Cailleteau, Laurence; Pons, Catherine; Ginsberg, Mark H.; Féral, Chloé C.

    2016-01-01

    CD98hc (SLC3A2) is the heavy chain component of the dimeric transmembrane glycoprotein CD98, which comprises the large neutral amino acid transporter LAT1 (SLC7A5) in cells. Overexpression of CD98hc occurs widely in cancer cells, and is associated with poor prognosis clinically, but its exact contributions to tumorigenesis are uncertain. In this study, we showed that that genetic deficiency of CD98hc protects against Ras-driven skin carcinogenesis. Deleting CD98hc after tumor induction was also sufficient to cause regression of existing tumors. Investigations into the basis for these effects defined two new functions of CD98hc that contribute to epithelial cancer beyond an intrinsic effect on CD98hc on tumor cell proliferation. First, CD98hc increased the stiffness of the tumor microenvironment. Second, CD98hc amplified the capacity of cells to respond to matrix rigidity, an essential factor in tumor development. Mechanistically, CD98hc mediated this stiffness-sensing by increasing Rho kinase (ROCK) activity, resulting in increased transcription mediated by YAP/TAZ, a nuclear relay for mechanical signals. Our results suggest that CD98hc contributes to carcinogenesis by amplifying a positive feedback loop which increases both extracellular matrix stiffness and resulting cellular responses. This work supports a rationale to explore the use of CD98hc inhibitors as cancer therapeutics, PMID:25267066

  8. Helical apolipoproteins stabilize ATP-binding cassette transporter A1 by protecting it from thiol protease-mediated degradation.

    PubMed

    Arakawa, Reijiro; Yokoyama, Shinji

    2002-06-21

    ATP-binding cassette transporter (ABC) A1 was increased by apolipoprotein A-I without an increase of its message in THP-1 cells. The pulse label study demonstrated that apoA-I retarded degradation of ABCA1. Similar changes were demonstrated by apoA-II, but the effect of high density lipoprotein was almost negligible on the basis of equivalent protein concentration. Thiol protease inhibitors (leupeptin and N-acetyl-Leu-Leu-norleucinal (ALLN)) increased ABCA1 and slowed its decay in the cells, whereas none of the proteosome-specific inhibitor lactacystin, other protease inhibitors, or the lysosomal inhibitor NH(4)Cl showed such effects. The effects of apoA-I and ALLN were additive for the increase of ABCA1, and the apoA-I-mediated cellular lipid release was enhanced by ALLN. The data suggest that ABCA1 is rapidly degraded by a thiol protease(s) in the cells unless helical apolipoproteins in their lipid-free form stabilize ABCA1 by protecting it from protease-mediated degradation.

  9. Overexpression of human kynurenine-3-monooxygenase protects against 3-hydroxykynurenine-mediated apoptosis through bidirectional nonlinear feedback.

    PubMed

    Wilson, K; Auer, M; Binnie, M; Zheng, X; Pham, N T; Iredale, J P; Webster, S P; Mole, D J

    2016-04-14

    Kynurenine 3-monooxygenase (KMO) is a critical regulator of inflammation. The preferred KMO substrate, kynurenine, is converted to 3-hydroxykynurenine (3HK), and this product exhibits cytotoxicity through mechanisms that culminate in apoptosis. Here, we report that overexpression of human KMO with orthotopic localisation to mitochondria creates a metabolic environment during which the cell exhibits increased tolerance for exogenous 3HK-mediated cellular injury. Using the selective KMO inhibitor Ro61-8048, we show that KMO enzyme function is essential for cellular protection. Pan-caspase inhibition with Z-VAD-FMK confirmed apoptosis as the mode of cell death. By defining expression of pathway components upstream and downstream of KMO, we observed alterations in other key kynurenine pathway components, particularly tryptophan-2,3-dioxygenase upregulation, through bidirectional nonlinear feedback. KMO overexpression also increased expression of inducible nitric oxide synthase (iNOS). These changes in gene expression are functionally relevant, because siRNA knockdown of the pathway components kynureninase and quinolinate phosphoribosyl transferase caused cells to revert to a state of susceptibility to 3HK-mediated apoptosis. In summary, KMO overexpression, and importantly KMO activity, have metabolic repercussions that fundamentally affect resistance to cell stress.

  10. Overexpression of human kynurenine-3-monooxygenase protects against 3-hydroxykynurenine-mediated apoptosis through bidirectional nonlinear feedback

    PubMed Central

    Wilson, K; Auer, M; Binnie, M; Zheng, X; Pham, N T; Iredale, J P; Webster, S P; Mole, D J

    2016-01-01

    Kynurenine 3-monooxygenase (KMO) is a critical regulator of inflammation. The preferred KMO substrate, kynurenine, is converted to 3-hydroxykynurenine (3HK), and this product exhibits cytotoxicity through mechanisms that culminate in apoptosis. Here, we report that overexpression of human KMO with orthotopic localisation to mitochondria creates a metabolic environment during which the cell exhibits increased tolerance for exogenous 3HK-mediated cellular injury. Using the selective KMO inhibitor Ro61-8048, we show that KMO enzyme function is essential for cellular protection. Pan-caspase inhibition with Z-VAD-FMK confirmed apoptosis as the mode of cell death. By defining expression of pathway components upstream and downstream of KMO, we observed alterations in other key kynurenine pathway components, particularly tryptophan-2,3-dioxygenase upregulation, through bidirectional nonlinear feedback. KMO overexpression also increased expression of inducible nitric oxide synthase (iNOS). These changes in gene expression are functionally relevant, because siRNA knockdown of the pathway components kynureninase and quinolinate phosphoribosyl transferase caused cells to revert to a state of susceptibility to 3HK-mediated apoptosis. In summary, KMO overexpression, and importantly KMO activity, have metabolic repercussions that fundamentally affect resistance to cell stress. PMID:27077813

  11. Arg354 in the catalytic centre of bovine liver catalase is protected from methylglyoxal-mediated glycation.

    PubMed

    Scheckhuber, Christian Q

    2015-12-30

    In addition to controlled post-translational modifications proteins can be modified with highly reactive compounds. Usually this leads to a compromised functionality of the protein. Methylglyoxal is one of the most common agents that attack arginine residues. Methylglyoxal is also regarded as a pro-oxidant that affects cellular redox homeostasis by contributing to the formation of reactive oxygen species. Antioxidant enzymes like catalase are required to protect the cell from oxidative damage. These enzymes are also targets for methylglyoxal-mediated modification which could severely affect their catalytic activity in breaking down reactive oxygen species to less reactive or inert compounds. Here, bovine liver catalase was incubated with high levels of methylglyoxal to induce its glycation. This treatment did not lead to a pronounced reduction of enzymatic activity. Subsequently methylglyoxal-mediated arginine modifications (hydroimidazolone and dihydroxyimidazolidine) were quantitatively analysed by sensitive nano high performance liquid chromatography/electron spray ionisation/tandem mass spectrometry. Whereas several arginine residues displayed low to moderate levels of glycation (e.g., Arg93, Arg365, Arg444) Arg354 in the active centre of catalase was never found to be modified. Bovine liver catalase is able to tolerate very high levels of the modifying α-oxoaldehyde methylglyoxal so that its essential enzymatic function is not impaired.

  12. Does the How Mediate the Why? A Multiple Replication Examination of Drinking Motives, Alcohol Protective Behavioral Strategies, and Alcohol Outcomes

    PubMed Central

    Bravo, Adrian J.; Prince, Mark A.; Pearson, Matthew R.

    2015-01-01

    Objective: The present study attempted to assess the evidence of use of protective behavioral strategies (PBS) as a mediator in the relationship between drinking motives and alcohol outcomes. Specifically, to understand various statistical approaches in modeling this proposed mediation model (e.g., drinking motives to PBS use to alcohol outcomes), we tried to replicate models based on earlier research. Method: To maximize the robustness of our replication attempts, we conducted each replication attempt across two distinct data sets whenever possible. Participants were recruited from psychology department research pools at a large southeastern U.S. university (Sample 1; n = 774) and a large southwestern U.S. university (Sample 2; n = 594). We matched the original articles’ analytic procedures as closely as possible including overall analysis approach, measurement of variables, and inclusion/exclusion criteria. Results: Consistent with previous studies, we found that PBS use may be a mechanism through which both positively reinforcing (i.e., social and enhancement) motives and coping motives relate to alcohol outcomes (e.g., alcohol-related consequences). Specifically, students who tend to drink for these specific motives appear to use fewer PBS, which may place them at risk for heavier, more problematic drinking. Conclusions: Our results suggest that when drinking motives are examined separately, they demonstrate differential relationships with PBS use and alcohol outcomes. Overall, it is clear that PBS use plays a role in the drinking motives–alcohol outcomes relationship, but this role varies by type of motive. PMID:26562595

  13. Nobiletin Induces Protective Autophagy Accompanied by ER-Stress Mediated Apoptosis in Human Gastric Cancer SNU-16 Cells.

    PubMed

    Moon, Jeong Yong; Cho, Somi Kim

    2016-07-14

    Nobiletin, a major component of citrus fruits, is a polymethoxyflavone derivative that exhibits anticancer activity against several forms of cancer, including SNU-16 human gastric cancer cells. To explore the nobiletin-induced cell death mechanism, we examined the changes in protein expression caused by nobiletin in human gastric cancer SNU-16 cells by means of two-dimensional gel electrophoresis (2-DGE), followed by peptide mass fingerprinting (PMF) analysis. Seventeen of 20 selected protein spots were successfully identified, including nine upregulated and eight downregulated proteins. In nobiletin-treated SNU-16 cells the glucose-regulated protein 78 kDa (GRP78) mRNA level was induced most significantly among six proteins related to cell survival and death. Western blot analysis was used to confirm the expression of GRP78 protein. We detected increases in the levels of the ER-stress related proteins inositol requiring enzyme 1 alpha (IRE1-α), activating transcription factor 4 (ATF-4), and C/EBP homology protein (CHOP), as well as GRP78, in response to nobiletin in SNU-16 cells. Furthermore, the ER stress-mediated apoptotic protein caspase-4 was proteolytically activated by nobiletin. Pretreatment with chloroquine, an autophagy inhibitor, strongly augmented apoptosis in SNU-16 cells, as evidenced by decreased cell viability, an increased number of sub-G1 phase cells and increased levels of cleaved PARP. Our results suggest that nobiletin-induced apoptosis in SNU-16 cells is mediated by pathways involving intracellular ER stress-mediated protective autophagy. Thus, the combination of nobiletin and an autophagy inhibitor could be a promising treatment for gastric cancer patients.

  14. PGC-1α Mediated Peripheral Nerve Protection of Tongxinluo in STZ-Induced Diabetic Rats

    PubMed Central

    Cui, Xiaopei; Feng, Hua; Xu, Xia; Li, Haijun

    2016-01-01

    Aim. To investigate the effect of Tongxinluo (Txl), a Chinese herbal compound, on diabetic peripheral neuropathy (DPN). Methods and Results. Diabetic rat model was established by peritoneal injection of streptozotocin (STZ). Txl ultrafine powder treatment for 16 weeks from the baseline significantly reversed the impairment of motor nerve conductive velocity (MNCV), mechanical hyperalgesia, and nerve structure. We further proved that Tongxinluo upregulates PGC-1α and its downstream factors including COX IV and SOD, which were involved in mitochondrial biogenesis. Conclusion. Our study indicates that the protective effect of Txl in diabetic neuropathy may be attributed to the induction of PGC-1α and its downstream targets. This finding may further illustrate the pleiotropic effect of the medicine. PMID:27504136

  15. IL-22 Restrains Tapeworm-Mediated Protection against Experimental Colitis via Regulation of IL-25 Expression

    PubMed Central

    Reyes, José L.; Fernando, Maria R.; Lopes, Fernando; Leung, Gabriella; Mancini, Nicole L.; Matisz, Chelsea E.; Wang, Arthur; McKay, Derek M.

    2016-01-01

    Interleukin (IL)-22, an immune cell-derived cytokine whose receptor expression is restricted to non-immune cells (e.g. epithelial cells), can be anti-inflammatory and pro-inflammatory. Mice infected with the tapeworm Hymenolepis diminuta are protected from dinitrobenzene sulphonic acid (DNBS)-induced colitis. Here we assessed expulsion of H. diminuta, the concomitant immune response and the outcome of DNBS-induced colitis in wild-type (WT) and IL-22 deficient mice (IL-22-/-) ± infection. Interleukin-22-/- mice had a mildly impaired ability to expel the worm and this correlated with reduced or delayed induction of TH2 immunity as measured by splenic and mesenteric lymph node production of IL-4, IL-5 and IL-13 and intestinal Muc-2 mRNA and goblet cell hyperplasia; in contrast, IL-25 increased in the small intestine of IL-22-/- mice 8 and 12 days post-infection compared to WT mice. In vitro experiments revealed that H. diminuta directly evoked epithelial production of IL-25 that was inhibited by recombinant IL-22. Also, IL-10 and markers of regulatory T cells were increased in IL-22-/- mice that displayed less DNBS (3 mg, ir. 72h)-induced colitis. Wild-type mice infected with H. diminuta were protected from colitis, as were infected IL-22-/- mice and the latter to a degree that they were almost indistinguishable from control, non-DNBS treated mice. Finally, treatment with anti-IL-25 antibodies exaggerated DNBS-induced colitis in IL-22-/- mice and blocked the anti-colitic effect of infection with H. diminuta. Thus, IL-22 is identified as an endogenous brake on helminth-elicited TH2 immunity, reducing the efficacy of expulsion of H. diminuta and limiting the effectiveness of the anti-colitic events mobilized following infection with H. diminuta in a non-permissive host. PMID:27055194

  16. RIPK1 protects from TNF-α-mediated liver damage during hepatitis

    PubMed Central

    Filliol, Aveline; Piquet-Pellorce, Claire; Le Seyec, Jacques; Farooq, Muhammad; Genet, Valentine; Lucas-Clerc, Catherine; Bertin, John; Gough, Peter J; Dimanche-Boitrel, Marie-Thérèse; Vandenabeele, Peter; Bertrand, Mathieu JM; Samson, Michel

    2016-01-01

    Cell death of hepatocytes is a prominent characteristic in the pathogenesis of liver disease, while hepatolysis is a starting point of inflammation in hepatitis and loss of hepatic function. However, the precise molecular mechanisms of hepatocyte cell death, the role of the cytokines of hepatic microenvironment and the involvement of intracellular kinases, remain unclear. Tumor necrosis factor alpha (TNF-α) is a key cytokine involved in cell death or survival pathways and the role of RIPK1 has been associated to the TNF-α-dependent signaling pathway. We took advantage of two different deficient mouse lines, the RIPK1 kinase dead knock-in mice (Ripk1K45A) and the conditional knockout mice lacking RIPK1 only in liver parenchymal cells (Ripk1LPC-KO), to characterize the role of RIPK1 and TNF-α in hepatitis induced by concanavalin A (ConA). Our results show that RIPK1 is dispensable for liver homeostasis under steady-state conditions but in contrast, RIPK1 kinase activity contributes to caspase-independent cell death induction following ConA injection and RIPK1 also serves as a scaffold, protecting hepatocytes from massive apoptotic cell death in this model. In the Ripk1LPC-KO mice challenged with ConA, TNF-α triggers apoptosis, responsible for the observed severe hepatitis. Mechanism potentially involves both TNF-independent canonical NF-κB activation, as well as TNF-dependent, but canonical NF-κB-independent mechanisms. In conclusion, our results suggest that RIPK1 kinase activity is a pertinent therapeutic target to protect liver against excessive cell death in liver diseases. PMID:27831558

  17. Synaptic activity protects neurons against calcium-mediated oxidation and contraction of mitochondria during excitotoxicity.

    PubMed

    Depp, Constanze; Bas-Orth, Carlos; Schroeder, Lisa; Hellwig, Andrea; Bading, Hilmar

    2017-10-07

    Excitotoxicity triggered by extrasynaptic N-methyl-D-aspartate-type glutamate receptors (NMDARs) has been implicated in many neurodegenerative conditions, including Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis, and stroke. Mitochondrial calcium overload leading to mitochondrial dysfunction represents an early event in excitotoxicity. Neurons are rendered resistant to excitotoxicity by previous periods of synaptic activity that activates a nuclear calcium-driven neuroprotective gene program. This process, termed acquired neuroprotection, involves transcriptional repression of the mitochondrial calcium uniporter leading to a reduction in excitotoxcity-associated mitochondrial calcium load. As mitochondrial calcium and the production of reactive oxygen species (ROS) may be linked, we monitored excitotoxicity-associated changes in the mitochondrial redox status using the ratiometric glutathione redox potential indicator, Grx1-roGFP2, targeted to the mitochondrial matrix. Aim of this study was to investigate if suppression of oxidative stress underlies mitoprotection afforded by synaptic activity. We found that synaptic activity protects primary rat hippocampal neurons against acute excitotoxicity-induced mitochondrial oxidative stress and mitochondrial contraction associated with it. Downregulation of the mitochondrial uniporter by genetic means mimics the protective effect of synaptic activity on mitochondrial redox status. These findings indicate that oxidative stress acts downstream of mitochondrial calcium overload in excitotoxicity. Innovation and conclusion: We established mito-Grx1-roGFP2 as a reliable and sensitive tool to monitor rapid redox changes in mitochondria during excitotoxicity. Our results highlight the importance of developing means of blocking mitochondrial calcium overload for therapeutic targeting of oxidative stress and mitochondrial dysfunction in neurodegenerative diseases.

  18. IL-22 Restrains Tapeworm-Mediated Protection against Experimental Colitis via Regulation of IL-25 Expression.

    PubMed

    Reyes, José L; Fernando, Maria R; Lopes, Fernando; Leung, Gabriella; Mancini, Nicole L; Matisz, Chelsea E; Wang, Arthur; McKay, Derek M

    2016-04-01

    Interleukin (IL)-22, an immune cell-derived cytokine whose receptor expression is restricted to non-immune cells (e.g. epithelial cells), can be anti-inflammatory and pro-inflammatory. Mice infected with the tapeworm Hymenolepis diminuta are protected from dinitrobenzene sulphonic acid (DNBS)-induced colitis. Here we assessed expulsion of H. diminuta, the concomitant immune response and the outcome of DNBS-induced colitis in wild-type (WT) and IL-22 deficient mice (IL-22-/-) ± infection. Interleukin-22-/- mice had a mildly impaired ability to expel the worm and this correlated with reduced or delayed induction of TH2 immunity as measured by splenic and mesenteric lymph node production of IL-4, IL-5 and IL-13 and intestinal Muc-2 mRNA and goblet cell hyperplasia; in contrast, IL-25 increased in the small intestine of IL-22-/- mice 8 and 12 days post-infection compared to WT mice. In vitro experiments revealed that H. diminuta directly evoked epithelial production of IL-25 that was inhibited by recombinant IL-22. Also, IL-10 and markers of regulatory T cells were increased in IL-22-/- mice that displayed less DNBS (3 mg, ir. 72h)-induced colitis. Wild-type mice infected with H. diminuta were protected from colitis, as were infected IL-22-/- mice and the latter to a degree that they were almost indistinguishable from control, non-DNBS treated mice. Finally, treatment with anti-IL-25 antibodies exaggerated DNBS-induced colitis in IL-22-/- mice and blocked the anti-colitic effect of infection with H. diminuta. Thus, IL-22 is identified as an endogenous brake on helminth-elicited TH2 immunity, reducing the efficacy of expulsion of H. diminuta and limiting the effectiveness of the anti-colitic events mobilized following infection with H. diminuta in a non-permissive host.

  19. TALEN-Mediated Knockout of CCR5 Confers Protection Against Infection of Human Immunodeficiency Virus.

    PubMed

    Shi, Bingjie; Li, Juan; Shi, Xuanling; Jia, Wenxu; Wen, Yi; Hu, Xiongbing; Zhuang, Fengfeng; Xi, Jianzhong; Zhang, Linqi

    2017-02-01

    Transcription activator-like effector nuclease (TALEN) represents a valuable tool for genomic engineering due to its single-nucleotide precision, high nuclease activity, and low cytotoxicity. We report here systematic design and characterization of 28 novel TALENs targeting multiple regions of CCR5 gene (CCR5-TALEN) which encodes the co-receptor critical for entry of human immunodeficiency virus type I (HIV-1). By systemic characterization of these CCR5-TALENs, we have identified one (CCR5-TALEN-515) with higher nuclease activity, specificity, and lower cytotoxicity compared with zinc-finger nuclease (CCR5-ZFN) currently undergoing clinical trials. Sequence analysis of target cell line GHOST-CCR5-CXCR4 and human primary CD4 T cells showed that the double-strand breaks at the TALEN targeted sites resulted in truncated or nonfunctional CCR5 proteins thereby conferring protection against HIV-1 infection in vitro. None of the CCR5-TALENs had detectable levels of off-target nuclease activity against the homologous region in CCR2 although substantial level was identified for CCR5-ZFN in the primary CD4 T cells. Our results suggest that the CCR5-TALENs identified here are highly functional nucleases that produce protective genetic alterations to human CCR5. Application of these TALENs directly to the primary CD4 T cells and CD34 hematopoietic stem cells (HSCs) of infected individuals could help to create an immune system resistant to HIV-1 infection, recapitulating the success of "Berlin patient" and serving as an essential first step towards a "functional" cure of AIDS.

  20. Polyphenol oxidase-mediated protection against oxidative stress is not associated with enhanced photosynthetic efficiency

    PubMed Central

    Boeckx, Tinne; Webster, Richard; Winters, Ana L.; Webb, K. Judith; Gay, Alan; Kingston-Smith, Alison H.

    2015-01-01

    Background and Aims Polyphenol oxidases (PPOs) catalyse the oxidation of monophenols and/or o-diphenols to highly reactive o-quinones, which in turn interact with oxygen and proteins to form reactive oxygen species (ROS) and typical brown-pigmented complexes. Hence PPOs can affect local levels of oxygen and ROS. Although the currently known substrates are located in the vacuole, the enzyme is targeted to the thylakoid lumen, suggesting a role for PPOs in photosynthesis. The current study was designed to investigate the potential involvement of PPOs in the photosynthetic response to oxidative stress. Methods Photosynthesis (A, Fv/Fm, ΦPSII, qN, qP, NPQ) was measured in leaves of a wild-type and a low-PPO mutant of red clover (Trifolium pratense ‘Milvus’) under control conditions and under a stress treatment designed to induce photooxidative stress: cold/high light (2 °C/580 µmol m2 s–1) or 0–10 µm methyl viologen. Foliar protein content and oxidation state were also determined. Key Results Photosynthetic performance, and chlorophyll and protein content during 4 d of cold/high light stress and 3 d of subsequent recovery under control growth conditions showed similar susceptibility to stress in both lines. However, more extensive oxidative damage to protein in mutants than wild-types was observed after treatment of attached leaves with methyl viologen. In addition, PPO activity could be associated with an increased capacity to dissipate excess energy, but only at relatively low methyl viologen doses. Conclusions The presence of PPO activity in leaves did not correspond to a direct role for the enzyme in the regulation or protection of photosynthesis under cold stress. However, an indication that PPO could be involved in cellular protection against low-level oxidative stress requires further investigation. PMID:26041733

  1. Dynamics of symbiont-mediated antibiotic production reveal efficient long-term protection for beewolf offspring

    PubMed Central

    2013-01-01

    Background Insects have evolved a wide range of mechanisms to defend themselves and their offspring against antagonists. One of these strategies involves the utilization of antimicrobial compounds provided by symbiotic bacteria to protect the host or its nutritional resources from pathogens and parasites. In the symbiosis of the solitary digger wasp, Philanthus triangulum (Hymenoptera, Crabronidae), the bacterial symbiont ‘Candidatus Streptomyces philanthi’ defends the developing larvae against pathogens by producing a mixture of at least nine antimicrobial substances on the cocoon surface. This antibiotic cocktail inhibits the growth of a broad range of detrimental fungi and bacteria, thereby significantly enhancing the offspring’s survival probability. Results Here we show that the production of antimicrobial compounds by the beewolf symbionts is confined to the first two weeks after cocoon spinning, leading to a high concentration of piericidins and streptochlorin on the cocoon surface. Expression profiling of housekeeping, sporulation, and antibiotic biosynthesis genes indicates that antibiotic production coincides with morphological differentiation that enables the symbionts to survive the nutrient-limited conditions on the beewolf cocoon. The antibiotic substances remain stable on the cocoon surface for the entire duration of the beewolf’s hibernation period, demonstrating that the compounds are resistant against environmental influences. Conclusions The antibiotic production by the beewolf symbionts serves as a reliable protection for the wasp offspring against pathogenic microorganisms during the long and unpredictable developmental phase in the subterranean brood cells. Thus, the beewolf-Streptomyces symbiosis provides one of the rare examples of antibiotics serving as an efficient defense in the natural environment and may aid in devising new strategies for the utilization of antibiotic combination therapies in human medicine against increasingly

  2. Vagus nerve stimulation mediates protection from kidney ischemia-reperfusion injury through α7nAChR+ splenocytes

    PubMed Central

    Inoue, Tsuyoshi; Abe, Chikara; Sung, Sun-sang J.; Moscalu, Stefan; Jankowski, Jakub; Huang, Liping; Ye, Hong; Guyenet, Patrice G.

    2016-01-01

    The nervous and immune systems interact in complex ways to maintain homeostasis and respond to stress or injury, and rapid nerve conduction can provide instantaneous