Signaling dynamics of palmitate-induced ER stress responses mediated by ATF4 in HepG2 cells

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Cho Hyunju

2013-01-01

Full Text Available Abstract Background Palmitic acid, the most common saturated free fatty acid, has been implicated in ER (endoplasmic reticulum stress-mediated apoptosis. This lipoapotosis is dependent, in part, on the upregulation of the activating transcription factor-4 (ATF4. To better understand the mechanisms by which palmitate upregulates the expression level of ATF4, we integrated literature information on palmitate-induced ER stress signaling into a discrete dynamic model. The model provides an in silico framework that enables simulations and predictions. The model predictions were confirmed through further experiments in human hepatocellular carcinoma (HepG2 cells and the results were used to update the model and our current understanding of the signaling induced by palmitate. Results The three key things from the in silico simulation and experimental results are: 1 palmitate induces different signaling pathways (PKR (double-stranded RNA-activated protein kinase, PERK (PKR-like ER kinase, PKA (cyclic AMP (cAMP-dependent protein kinase A in a time dependent-manner, 2 both ATF4 and CREB1 (cAMP-responsive element-binding protein 1 interact with the Atf4 promoter to contribute to a prolonged accumulation of ATF4, and 3 CREB1 is involved in ER-stress induced apoptosis upon palmitate treatment, by regulating ATF4 expression and possibly Ca2+ dependent-CaM (calmodulin signaling pathway. Conclusion The in silico model helped to delineate the essential signaling pathways in palmitate-mediated apoptosis.

GPBAR1/TGR5 mediates bile acid-induced cytokine expression in murine Kupffer cells.

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Guiyu Lou

Full Text Available GPBAR1/TGR5 is a novel plasma membrane-bound G protein-coupled bile acid (BA receptor. BAs are known to induce the expression of inflammatory cytokines in the liver with unknown mechanism. Here we show that without other external stimuli, TGR5 activation alone induced the expression of interleukin 1β (IL-1β and tumor necrosis factor-α (TNF-α in murine macrophage cell line RAW264.7 or murine Kupffer cells. The TGR5-mediated increase of pro-inflammatory cytokine expression was suppressed by JNK inhibition. Moreover, the induced pro-inflammatory cytokine expression in mouse liver by 1% cholic acid (CA diet was blunted in JNK-/- mice. TGR5 activation by its ligands enhanced the phosphorylation levels, DNA-binding and trans-activities of c-Jun and ATF2 transcription factors. Finally, the induced pro-inflammatory cytokine expression in Kupffer cells by TGR5 activation correlated with the suppression of Cholesterol 7α-hydroxylase (Cyp7a1 expression in murine hepatocytes. These results suggest that TGR5 mediates the BA-induced pro-inflammatory cytokine production in murine Kupffer cells through JNK-dependent pathway. This novel role of TGR5 may correlate to the suppression of Cyp7a1 expression in hepatocytes and contribute to the delicate BA feedback regulation.

A pivotal role of the jasmonic acid signal pathway in mediating radiation-induced bystander effects in Arabidopsis thaliana.

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Wang, Ting; Xu, Wei; Deng, Chenguang; Xu, Shaoxin; Li, Fanghua; Wu, Yuejin; Wu, Lijun; Bian, Po

Although radiation-induced bystander effects (RIBE) in Arabidopsis thaliana have been well demonstrated in vivo, little is known about their underlying mechanisms, particularly with regard to the participating signaling molecules and signaling pathways. In higher plants, jasmonic acid (JA) and its bioactive derivatives are well accepted as systemic signal transducers that are produced in response to various environmental stresses. It is therefore speculated that the JA signal pathway might play a potential role in mediating radiation-induced bystander signaling of root-to-shoot. In the present study, pretreatment of seedlings with Salicylhydroxamic acid, an inhibitor of lipoxigenase (LOX) in JA biosynthesis, significantly suppressed RIBE-mediated expression of the AtRAD54 gene. After root irradiation, the aerial parts of A. thaliana mutants deficient in JA biosynthesis (aos) and signaling cascades (jar1-1) showed suppressed induction of the AtRAD54 and AtRAD51 genes and TSI and 180-bp repeats, which have been extensively used as endpoints of bystander genetic and epigenetic effects in plants. These results suggest an involvement of the JA signal pathway in the RIBE of plants. Using the root micro-grafting technique, the JA signal pathway was shown to participate in both the generation of bystander signals in irradiated root cells and radiation responses in the bystander aerial parts of plants. The over-accumulation of endogenous JA in mutant fatty acid oxygenation up-regulated 2 (fou2), in which mutation of the Two Pore Channel 1 (TPC1) gene up-regulates expression of the LOX and allene oxide synthase (AOS) genes, inhibited RIBE-mediated expression of the AtRAD54 gene, but up-regulated expression of the AtKU70 and AtLIG4 genes in the non-homologous end joining (NHEJ) pathway. Considering that NHEJ is employed by plants with increased DNA damage, the switch from HR to NHEJ suggests that over-accumulation of endogenous JA might enhance the radiosensitivity of plants

Lack of TXNIP protects against mitochondria-mediated apoptosis but not against fatty acid-induced ER stress-mediated beta-cell death.

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Chen, Junqin; Fontes, Ghislaine; Saxena, Geetu; Poitout, Vincent; Shalev, Anath

2010-02-01

We have previously shown that lack of thioredoxin-interacting protein (TXNIP) protects against diabetes and glucotoxicity-induced beta-cell apoptosis. Because the role of TXNIP in lipotoxicity is unknown, the goal of the present study was to determine whether TXNIP expression is regulated by fatty acids and whether TXNIP deficiency also protects beta-cells against lipoapoptosis. RESARCH DESIGN AND METHODS: To determine the effects of fatty acids on beta-cell TXNIP expression, INS-1 cells and isolated islets were incubated with/without palmitate and rats underwent cyclic infusions of glucose and/or Intralipid prior to islet isolation and analysis by quantitative real-time RT-PCR and immunoblotting. Using primary wild-type and TXNIP-deficient islets, we then assessed the effects of palmitate on apoptosis (transferase-mediated dUTP nick-end labeling [TUNEL]), mitochondrial death pathway (cytochrome c release), and endoplasmic reticulum (ER) stress (binding protein [BiP], C/EBP homologous protein [CHOP]). Effects of TXNIP deficiency were also tested in the context of staurosporine (mitochondrial damage) or thapsigargin (ER stress). Glucose elicited a dramatic increase in islet TXNIP expression both in vitro and in vivo, whereas fatty acids had no such effect and, when combined with glucose, even abolished the glucose effect. We also found that TXNIP deficiency does not effectively protect against palmitate or thapsigargin-induced beta-cell apoptosis, but specifically prevents staurosporine- or glucose-induced toxicity. Our results demonstrate that unlike glucose, fatty acids do not induce beta-cell expression of proapoptotic TXNIP. They further reveal that TXNIP deficiency specifically inhibits the mitochondrial death pathway underlying beta-cell glucotoxicity, whereas it has very few protective effects against ER stress-mediated lipoapoptosis.

Mechanisms of bile acid mediated inflammation in the liver.

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Li, Man; Cai, Shi-Ying; Boyer, James L

2017-08-01

Bile acids are synthesized in the liver and are the major component in bile. Impaired bile flow leads to cholestasis that is characterized by elevated levels of bile acid in the liver and serum, followed by hepatocyte and biliary injury. Although the causes of cholestasis have been extensively studied, the molecular mechanisms as to how bile acids initiate liver injury remain controversial. In this chapter, we summarize recent advances in the pathogenesis of bile acid induced liver injury. These include bile acid signaling pathways in hepatocytes as well as the response of cholangiocytes and innate immune cells in the liver in both patients with cholestasis and cholestatic animal models. We focus on how bile acids trigger the production of molecular mediators of neutrophil recruitment and the role of the inflammatory response in this pathological process. These advances point to a number of novel targets where drugs might be judged to be effective therapies for cholestatic liver injury. Copyright © 2017 Elsevier Ltd. All rights reserved.

PAMP-induced defense responses in potato require both salicylic acid and jasmonic acid.

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Halim, Vincentius A; Altmann, Simone; Ellinger, Dorothea; Eschen-Lippold, Lennart; Miersch, Otto; Scheel, Dierk; Rosahl, Sabine

2009-01-01

To elucidate the molecular mechanisms underlying pathogen-associated molecular pattern (PAMP)-induced defense responses in potato (Solanum tuberosum), the role of the signaling compounds salicylic acid (SA) and jasmonic acid (JA) was analyzed. Pep-13, a PAMP from Phytophthora, induces the accumulation of SA, JA and hydrogen peroxide, as well as the activation of defense genes and hypersensitive-like cell death. We have previously shown that SA is required for Pep-13-induced defense responses. To assess the importance of JA, RNA interference constructs targeted at the JA biosynthetic genes, allene oxide cyclase and 12-oxophytodienoic acid reductase, were expressed in transgenic potato plants. In addition, expression of the F-box protein COI1 was reduced by RNA interference. Plants expressing the RNA interference constructs failed to accumulate the respective transcripts in response to wounding or Pep-13 treatment, neither did they contain significant amounts of JA after elicitation. In response to infiltration of Pep-13, the transgenic plants exhibited a highly reduced accumulation of reactive oxygen species as well as reduced hypersensitive cell death. The ability of the JA-deficient plants to accumulate SA suggests that SA accumulation is independent or upstream of JA accumulation. These data show that PAMP responses in potato require both SA and JA and that, in contrast to Arabidopsis, these compounds act in the same signal transduction pathway. Despite their inability to fully respond to PAMP treatment, the transgenic RNA interference plants are not altered in their basal defense against Phytophthora infestans.

Rpi-blb2-Mediated Hypersensitive Cell Death Caused by Phytophthora infestans AVRblb2 Requires SGT1, but not EDS1, NDR1, Salicylic Acid-, Jasmonic Acid-, or Ethylene-Mediated Signaling

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Sang-Keun Oh

2014-09-01

Full Text Available Potato Rpi-blb2 encodes a protein with a coiled-coil-nucleotide binding site and leucine-rich repeat (CC-NBS-LRR motif that recognizes the Phytophthora infestans AVRblb2 effector and triggers hypersensitive cell death (HCD. To better understand the components required for Rpi-blb2-mediated HCD in plants, we used virus-induced gene silencing to repress candidate genes in Rpi-blb2-transgenic Nicotiana benthamiana plants and assayed the plants for AVRblb2 effector. Rpi-blb2 triggers HCD through NbSGT1-mediated pathways, but not NbEDS1- or NbNDR1-mediated pathways. In addition, the role of salicylic acid (SA, jasmonic acid (JA, and ethylene (ET in Rpi-blb2-mediated HCD were analyzed by monitoring of the responses of NbICS1-, NbCOI1-, or NbEIN2-silenced or Rpi-blb2::NahG-transgenic plants. Rpi-blb2-mediated HCD in response to AVRblb2 was not associated with SA accumulation. Thus, SA affects Rpi-blb2-mediated resistance against P. infestans, but not Rpi-blb2-mediated HCD in response to AVRblb2. Additionally, JA and ET signaling were not required for Rpi-blb2-mediated HCD in N. benthamiana. Taken together, these findings suggest that NbSGT1 is a unique positive regulator of Rpi-blb2-mediated HCD in response to AVRblb2, but EDS1, NDR1, SA, JA, and ET are not required.

The sesquiterpene botrydial produced by Botrytis cinerea induces the hypersensitive response on plant tissues and its action is modulated by salicylic acid and jasmonic acid signaling.

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Rossi, Franco Rubén; Gárriz, Andrés; Marina, María; Romero, Fernando Matías; Gonzalez, María Elisa; Collado, Isidro González; Pieckenstain, Fernando Luis

2011-08-01

Botrytis cinerea, as a necrotrophic fungus, kills host tissues and feeds on the remains. This fungus is able to induce the hypersensitive response (HR) on its hosts, thus taking advantage on the host's defense machinery for generating necrotic tissues. However, the identity of HR effectors produced by B. cinerea is not clear. The aim of this work was to determine whether botrydial, a phytotoxic sesquiterpene produced by B. cinerea, is able to induce the HR on plant hosts, using Arabidopsis thaliana as a model. Botrydial induced the expression of the HR marker HSR3, callose deposition, and the accumulation of reactive oxygen species and phenolic compounds. Botrydial also induced the expression of PR1 and PDF1.2, two pathogenesis-related proteins involved in defense responses regulated by salicylic acid (SA) and jasmonic acid (JA), respectively. A. thaliana and tobacco plants defective in SA signaling were more resistant to botrydial than wild-type plants, as opposed to A. thaliana plants defective in JA signaling, which were more sensitive. It can be concluded that botrydial induces the HR on its hosts and its effects are modulated by host signaling pathways mediated by SA and JA.

Cyclic ADP-ribose and IP3 mediate abscisic acid-induced isoflavone accumulation in soybean sprouts

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Jiao, Caifeng; Yang, Runqiang; Gu, Zhenxin

2016-01-01

In this study, the roles of ABA-cADPR-Ca 2+ and ABA-IP3-Ca 2+ signaling pathways in UV-B-induced isoflavone accumulation in soybean sprouts were investigated. Results showed that abscisic acid (ABA) up regulated cyclic ADP-ribose (cADPR) and inositol 1,4,5-trisphosphate (IP3) levels in soybean sprouts under UV-B radiation. Furthermore, cADPR and IP3, as second messengers of UV-B-triggered ABA, induced isoflavone accumulation by up-regulating proteins and genes expression and activity of isoflavone biosynthetic-enzymes (chalcone synthase, CHS; isoflavone synthase, IFS). After Ca 2+ was chelated by EGTA, isoflavone content decreased. Overall, ABA-induced cADPR and IP3 up regulated isoflavone accumulation which was mediated by Ca 2+ signaling via enhancing the expression of proteins and genes participating in isoflavone biosynthesis in soybean sprouts under UV-B radiation. - Highlights: • UV-B-induced cADPR and IP3 synthesis was mediated by ABA. • cADPR and IP3 were involved in UV-B-ABA-induced isoflavone accumulation. • cADPR and IP3-induced isoflavone accumulation may be mediated by Ca 2+ . • ABA, cADPR, IP3 and Ca 2+ could activate proteins expression of CHS and IFS.

Chronically Elevated Levels of Short-Chain Fatty Acids Induce T Cell-Mediated Ureteritis and Hydronephrosis.

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Park, Jeongho; Goergen, Craig J; HogenEsch, Harm; Kim, Chang H

2016-03-01

Short-chain fatty acids (SCFAs) are major products of gut microbial fermentation and profoundly affect host health and disease. SCFAs generate IL-10(+) regulatory T cells, which may promote immune tolerance. However, SCFAs can also induce Th1 and Th17 cells upon immunological challenges and, therefore, also have the potential to induce inflammatory responses. Because of the seemingly paradoxical SCFA activities in regulating T cells, we investigated, in depth, the impact of elevated SCFA levels on T cells and tissue inflammation in mice. Orally administered SCFAs induced effector (Th1 and Th17) and regulatory T cells in ureter and kidney tissues, and they induced T cell-mediated ureteritis, leading to kidney hydronephrosis (hereafter called acetate-induced renal disease, or C2RD). Kidney hydronephrosis in C2RD was caused by ureteral obstruction, which was, in turn, induced by SCFA-induced inflammation in the ureteropelvic junction and proximal ureter. Oral administration of all major SCFAs, such as acetate, propionate, and butyrate, induced the disease. We found that C2RD development is dependent on mammalian target of rapamycin activation, T cell-derived inflammatory cytokines such as IFN-γ and IL-17, and gut microbiota. Young or male animals were more susceptible than old or female animals, respectively. However, SCFA receptor (GPR41 or GPR43) deficiency did not affect C2RD development. Thus, SCFAs, when systemically administered at levels higher than physiological levels, cause dysregulated T cell responses and tissue inflammation in the renal system. The results provide insights into the immunological and pathological effects of chronically elevated SCFAs. Copyright © 2016 by The American Association of Immunologists, Inc.

Maternal immunity enhances Mycoplasma hyopneumoniae vaccination induced cell-mediated immune responses in piglets.

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Bandrick, Meggan; Theis, Kara; Molitor, Thomas W

2014-06-05

Passively acquired maternal derived immunity (MDI) is a double-edged sword. Maternal derived antibody-mediated immunity (AMI) and cell-mediated immunity (CMI) are critical immediate defenses for the neonate; however, MDI may interfere with the induction of active immunity in the neonate, i.e. passive interference. The effect of antigen-specific MDI on vaccine-induced AMI and CMI responses to Mycoplasma hyopneumoniae (M. hyopneumoniae) was assessed in neonatal piglets. To determine whether CMI and AMI responses could be induced in piglets with MDI, piglets with high and low levels of maternal M. hyopneumoniae-specific immunity were vaccinated against M. hyopneumoniae at 7 d of age. Piglet M. hyopneumoniae-specific antibody, lymphoproliferation, and delayed type hypersensitivity (DTH) responses were measured 7 d and 14 d post vaccination. Piglets with M. hyopneumoniae-specific MDI failed to show vaccine-induced AMI responses; there was no rise in M. hyopneumoniae antibody levels following vaccination of piglets in the presence of M. hyopneumoniae-specific MDI. However, piglets with M. hyopneumoniae-specific MDI had primary (antigen-specific lymphoproliferation) and secondary (DTH) M. hyopneumoniae-specific CMI responses following vaccination. In this study neonatal M. hyopneumoniae-specific CMI was not subject to passive interference by MDI. Further, it appears that both maternal derived and endogenous CMI contribute to M. hyopneumoniae-specific CMI responses in piglets vaccinated in the face of MDI.

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

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Nozomi Kawazoe

2017-06-01

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

Epidermal growth factor receptor signaling mediates aldosterone-induced profibrotic responses in kidney

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Sheng, Lili; Yang, Min; Ding, Wei [Department of Nephrology, Shanghai Fifth People' s Hospital, Fudan University, Shanghai 200240 (China); Zhang, Minmin [Department of Nephrology, Shanghai Huashan Hospital, Fudan University, Shanghai 200240 (China); Niu, Jianying [Department of Nephrology, Shanghai Fifth People' s Hospital, Fudan University, Shanghai 200240 (China); Qiao, Zhongdong [School of Life Science and Biotechnology, Shanghai Jiaotong University, Shanghai 200240 (China); Gu, Yong, E-mail: yonggu@vip.163.com [Department of Nephrology, Shanghai Fifth People' s Hospital, Fudan University, Shanghai 200240 (China); Department of Nephrology, Shanghai Huashan Hospital, Fudan University, Shanghai 200240 (China)

2016-08-01

Aldosterone has been recognized as a risk factor for the development of chronic kidney disease (CKD). Studies have indicated that enhanced activation of epidermal growth factor receptor (EGFR) is associated with the development and progression of renal fibrosis. But if EGFR is involved in aldosterone-induced renal fibrosis is less investigated. In the present study, we examined the effect of erlotinib, an inhibitor of EGFR tyrosine kinase activity, on the progression of aldosterone-induced renal profibrotic responses in a murine model underwent uninephrectomy. Erlotinib-treated rats exhibited relieved structural lesion comparing with rats treated with aldosterone alone, as characterized by glomerular hypertrophy, mesangial cell proliferation and expansion. Also, erlotinib inhibited the expression of TGF-β, α-SMA and mesangial matrix proteins such as collagen Ⅳ and fibronectin. In cultured mesangial cells, inhibition of EGFR also abrogated aldosterone-induced expression of extracellular matrix proteins, cell proliferation and migration. We also demonstrated that aldosterone induced the phosphorylation of EGFR through generation of ROS. And the activation of EGFR resulted in the phosphorylation of ERK1/2, leading to the activation of profibrotic pathways. Taken together, we concluded that aldosterone-mediated tissue fibrosis relies on ROS induced EGFR/ERK activation, highlighting EGFR as a potential therapeutic target for modulating renal fibrosis. - Highlights: • EGFR was involved in aldosterone-induced renal profibrotic responses. • Aldosterone-induced EGFR activation was mediated by MR-dependent ROS generation. • EGFR activated the MAPK/ERK1/2 signaling to promote renal fibrosis.

Antagonism between salicylic and abscisic acid reflects early host-pathogen conflict and moulds plant defence responses.

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de Torres Zabala, Marta; Bennett, Mark H; Truman, William H; Grant, Murray R

2009-08-01

The importance of phytohormone balance is increasingly recognized as central to the outcome of plant-pathogen interactions. Recently it has been demonstrated that abscisic acid signalling pathways are utilized by the bacterial phytopathogen Pseudomonas syringae to promote pathogenesis. In this study, we examined the dynamics, inter-relationship and impact of three key acidic phytohormones, salicylic acid, abscisic acid and jasmonic acid, and the bacterial virulence factor, coronatine, during progression of P. syringae infection of Arabidopsis thaliana. We show that levels of SA and ABA, but not JA, appear to play important early roles in determining the outcome of the infection process. SA is required in order to mount a full innate immune responses, while bacterial effectors act rapidly to activate ABA biosynthesis. ABA suppresses inducible innate immune responses by down-regulating SA biosynthesis and SA-mediated defences. Mutant analyses indicated that endogenous ABA levels represent an important reservoir that is necessary for effector suppression of plant-inducible innate defence responses and SA synthesis prior to subsequent pathogen-induced increases in ABA. Enhanced susceptibility due to loss of SA-mediated basal resistance is epistatically dominant over acquired resistance due to ABA deficiency, although ABA also contributes to symptom development. We conclude that pathogen-modulated ABA signalling rapidly antagonizes SA-mediated defences. We predict that hormonal perturbations, either induced or as a result of environmental stress, have a marked impact on pathological outcomes, and we provide a mechanistic basis for understanding priming events in plant defence.

Biphasic Fluence-Response Curves for Phytochrome-Mediated Kalanchoë Seed Germination 1

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Rethy, Roger; Dedonder, Andrée; De Petter, Edwin; Van Wiemeersch, Luc; Fredericq, Henri; De Greef, Jan; Steyaert, Herman; Stevens, Hilde

1987-01-01

The fluence-response curves for the effect of two red pulses separated by 24 hours on the germination of Kalanchoe blossfeldiana Poelln. cv Vesuv seeds, incubated on gibberellic acid (GA3) are biphasic for suboptimal concentrations. The response in the low fluence range corresponds with a classical red/far-red reversible phytochrome mediated reaction. GA3 induces an additional response in the very low fluence range, which is also phytochrome mediated. The sensitivity to phytochrome-far-red absorbing form (Pfr), however, is increased about 20,000-fold, so that even far-red fluences become saturating. Both in the very low and low fluence response range, the maximal responses induced by saturating fluences are modulated by the GA3 concentration. GA3 having no direct influence on the phytochrome phototransformations, alters the Pfr requirement and determines the responding seed population fraction in the very low and low fluence range. The effet of GA3 appears to be on the transduction chain of the phytochrome signal. PMID:16665187

Glucocorticoids mediate stress-induced impairment of retrieval of stimulus-response memory.

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Atsak, Piray; Guenzel, Friederike M; Kantar-Gok, Deniz; Zalachoras, Ioannis; Yargicoglu, Piraye; Meijer, Onno C; Quirarte, Gina L; Wolf, Oliver T; Schwabe, Lars; Roozendaal, Benno

2016-05-01

Acute stress and elevated glucocorticoid hormone levels are well known to impair the retrieval of hippocampus-dependent 'declarative' memory. Recent findings suggest that stress might also impair the retrieval of non-hippocampal memories. In particular, stress shortly before retention testing was shown to impair the retrieval of striatal stimulus-response associations in humans. However, the mechanism underlying this stress-induced retrieval impairment of non-hippocampal stimulus-response memory remains elusive. In the present study, we investigated whether an acute elevation in glucocorticoid levels mediates the impairing effects of stress on retrieval of stimulus-response memory. Male Sprague-Dawley rats were trained on a stimulus-response task in an eight-arm radial maze until they learned to associate a stimulus, i.e., cue, with a food reward in one of the arms. Twenty-four hours after successful acquisition, they received a systemic injection of vehicle, corticosterone (1mg/kg), the corticosterone-synthesis inhibitor metyrapone (35mg/kg) or were left untreated 1h before retention testing. We found that the corticosterone injection impaired the retrieval of stimulus-response memory. We further found that the systemic injection procedure per se was stressful as the vehicle administration also increased plasma corticosterone levels and impaired the retrieval of stimulus-response memory. However, memory retrieval was not impaired when rats were tested 2min after the systemic vehicle injection, before any stress-induced elevation in corticosterone levels had occurred. Moreover, metyrapone treatment blocked the effect of injection stress on both plasma corticosterone levels and memory retrieval impairment, indicating that the endogenous corticosterone response mediates the stress-induced memory retrieval impairment. None of the treatments affected rats' locomotor activity or motivation to search for the food reward within the maze. These findings show that stress

p18(Hamlet) mediates different p53-dependent responses to DNA-damage inducing agents.

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Lafarga, Vanesa; Cuadrado, Ana; Nebreda, Angel R

2007-10-01

Cells organize appropriate responses to environmental cues by activating specific signaling networks. Two proteins that play key roles in coordinating stress responses are the kinase p38alpha (MAPK14) and the transcription factor p53 (TP53). Depending on the nature and the extent of the stress-induced damage, cells may respond by arresting the cell cycle or by undergoing cell death, and these responses are usually associated with the phosphorylation of particular substrates by p38alpha as well as the activation of specific target genes by p53. We recently characterized a new p38alpha substrate, named p18(Hamlet) (ZNHIT1), which mediates p53-dependent responses to different genotoxic stresses. Thus, cisplatin or UV light induce stabilization of the p18(Hamlet) protein, which then enhances the ability of p53 to bind to and activate the promoters of pro-apoptotic genes such as NOXA and PUMA leading to apoptosis induction. In a similar way, we report here that p18(Hamlet) can also mediate the cell cycle arrest induced in response to gamma-irradiation, by participating in the p53-dependent upregulation of the cell cycle inhibitor p21(Cip1) (CDKN1A).

Pretreatment of Sialic Acid Efficiently Prevents Lipopolysaccharide-Induced Acute Renal Failure and Suppresses TLR4/gp91-Mediated Apoptotic Signaling

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Shih-Ping Hsu

2016-05-01

Full Text Available Background/Aims: Lipopolysaccharides (LPS binding to Toll-like receptor 4 (TLR4 activate NADPH oxidase gp91 subunit-mediated inflammation and oxidative damage. Recognizing the high binding affinity of sialic acid (SA with LPS, we further explored the preventive potential of SA pretreatment on LPS-evoked acute renal failure (ARF. Methods: We determined the effect of intravenous SA 30 min before LPS-induced injury in urethane-anesthetized female Wistar rats by evaluating kidney reactive oxygen species (ROS responses, renal and systemic hemodynamics, renal function, histopathology, and molecular mechanisms. Results: LPS time-dependently reduced arterial blood pressure, renal microcirculation, and increased blood urea nitrogen and creatinine in the rats. LPS enhanced monocyte/macrophage infiltration and ROS production, and subsequently impaired kidneys with the enhancement of TLR4/NADPH oxidase gp91/Caspase 3/poly-(ADP-ribose-polymerase (PARP-mediated apoptosis in the kidneys. SA pretreatment effectively alleviated LPS-induced ARF. The levels of LPS-increased ED-1 infiltration and ROS production in the kidney were significantly depressed by SA pretreatment. Furthermore, SA pretreatment significantly depressed TLR4 activation, gp91 expression, and Caspase 3/PARP induced apoptosis in the kidneys. Conclusion: We suggest that pretreatment of SA significantly and preventively attenuated LPS-induced detrimental effects on systemic and renal hemodynamics, renal ROS production and renal function, as well as, LPS-activated TLR4/gp91/Caspase3 mediated apoptosis signaling.

Dose-dependent transitions in Nrf2-mediated adaptive response and related stress responses to hypochlorous acid in mouse macrophages

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Woods, Courtney G.; Fu Jingqi; Xue Peng; Hou Yongyong; Pluta, Linda J.; Yang Longlong; Zhang Qiang; Thomas, Russell S.; Andersen, Melvin E.; Pi Jingbo

2009-01-01

Hypochlorous acid (HOCl) is potentially an important source of cellular oxidative stress. Human HOCl exposure can occur from chlorine gas inhalation or from endogenous sources of HOCl, such as respiratory burst by phagocytes. Transcription factor Nrf2 is a key regulator of cellular redox status and serves as a primary source of defense against oxidative stress. We recently demonstrated that HOCl activates Nrf2-mediated antioxidant response in cultured mouse macrophages in a biphasic manner. In an effort to determine whether Nrf2 pathways overlap with other stress pathways, gene expression profiling was performed in RAW 264.7 macrophages exposed to HOCl using whole genome mouse microarrays. Benchmark dose (BMD) analysis on gene expression data revealed that Nrf2-mediated antioxidant response and protein ubiquitination were the most sensitive biological pathways that were activated in response to low concentrations of HOCl (< 0.35 mM). Genes involved in chromatin architecture maintenance and DNA-dependent transcription were also sensitive to very low doses. Moderate concentrations of HOCl (0.35 to 1.4 mM) caused maximal activation of the Nrf2 pathway and innate immune response genes, such as IL-1β, IL-6, IL-10 and chemokines. At even higher concentrations of HOCl (2.8 to 3.5 mM) there was a loss of Nrf2-target gene expression with increased expression of numerous heat shock and histone cluster genes, AP-1-family genes, cFos and Fra1 and DNA damage-inducible Gadd45 genes. These findings confirm an Nrf2-centric mechanism of action of HOCl in mouse macrophages and provide evidence of interactions between Nrf2, inflammatory, and other stress pathways.

Sporothrix schenckii Immunization, but Not Infection, Induces Protective Th17 Responses Mediated by Circulating Memory CD4+ T Cells

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Alberto García-Lozano

2018-06-01

Full Text Available Sporotrichosis is a chronic subcutaneous mycosis caused by the Sporothrix schenckii species complex and it is considered an emerging opportunistic infection in countries with tropical and subtropical climates. The host’s immune response has a main role in the development of this disease. However, it is unknown the features of the memory cellular immune response that could protect against the infection. Our results show that i.d. immunization in the ears of mice with inactivated S. schenckii conidia (iC combined with the cholera toxin (CT induces a cellular immune response mediated by circulating memory CD4+ T cells, which mainly produce interleukin 17 (IL-17. These cells mediate a strong delayed-type hypersensitivity (DTH reaction. Systemic and local protection against S. schenckii was mediated by circulating CD4+ T cells. In contrast, the infection induces a potent immune response in the skin mediated by CD4+ T cells, which have an effector phenotype that preferentially produce interferon gamma (IFN-γ and mediate a transitory DTH reaction. Our findings prove the potential value of the CT as a potent skin adjuvant when combined with fungal antigens, and they also have important implications for our better understanding of the differences between the memory immune response induced by the skin immunization and those induced by the infection; this knowledge enhances our understanding of how a protective immune response against a S. schenckii infection is developed.

[Ursodeoxycholic acid induced apoptosis of human hepatoma cells HepG2 and SMMC-7721 bymitochondrial-mediated pathway].

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Wu, Duan; Zhou, Jianyin; Yin, Zhenyu; Liu, Pingguo; Zhao, Yilin; Liu, Jianming; Wang, Xiaomin

2014-12-02

To explore the effects and underlying mechanisms of ursodeoxycholic acid on human hepatoma cells. HepG2 and SMMC-7721 HCC cell lines were respectively treated with ursodeoxycholic acid. And cell proliferation, apoptosis and the expression of Bax/Bcl-2 gene were detected by methyl thiazolyl tetrazolium (MTT), inverted microscopy, fluorescent microscopy, flow cytometry and Western blot. Ursodeoxycholic acid significantly inhibited the proliferation of human hepatoma cells in a concentration- and time-dependent manner. The half maximal inhibitory concentrations (IC50) of HepG2 and SMMC-7721 were 397.3 and 387.7 µg/ml respectively after a 48-hour treatment of 400 µg /ml ursodeoxycholic acid. And it also induced the apoptosis of HepG2 and SMMC-7721 cells, up-regulated Bax gene and down-regulated Bcl-2 gene. Ursodeoxycholic acid inhibits the proliferation of hepatoma cells and induce apoptosis by mitochondrial-mediated pathway.

Caffeic acid phenethyl ester inhibits 3-MC-induced CYP1A1 expression through induction of hypoxia-inducible factor-1α

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Kim, Hyung Gyun [Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon (Korea, Republic of); Han, Eun Hee [Division of Life Science, Korea Basic Science Institute, Daejeon (Korea, Republic of); Im, Ji Hye; Lee, Eun Ji; Jin, Sun Woo [Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon (Korea, Republic of); Jeong, Hye Gwang, E-mail: hgjeong@cnu.ac.kr [Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon (Korea, Republic of)

2015-09-25

Caffeic acid phenethyl ester (CAPE), a natural component of propolis, is reported to have anticarcinogenic properties, although its precise chemopreventive mechanism remains unclear. In this study, we examined the effects of CAPE on 3-methylcholanthrene (3-MC)-induced CYP1A1 expression and activities. CAPE reduced the formation of the benzo[a]pyrene-DNA adduct. Moreover, CAPE inhibited 3-MC-induced CYP1A1 activity, mRNA expression, protein level, and promoter activity. CAPE treatment also decreased 3-MC-inducible xenobiotic-response element (XRE)-linked luciferase, aryl hydrocarbons receptor (AhR) transactivation and nuclear localization. CAPE induced hypoxia inducible factor-1α (HIF-1α) protein level and HIF-1α responsible element (HRE) transcriptional activity. CAPE-mediated HIF-1α reduced 3-MC-inducible CYP1A1 protein expression. Taken together, CAPE decreases 3-MC-mediated CYP1A1 expression, and this inhibitory response is associated with inhibition of AhR and HIF-1α induction. - Highlights: • CAPE reduced the formation of the benzo[a]pyrene-DNA adduct. • CAPE inhibited 3-MC-induced CYP1A1 expression. • CAPE induced HIF-1α induction. • CAPE-mediated HIF-1α reduced 3-MC-inducible CYP1A1 expression.

Ethylene Responses in Rice Roots and Coleoptiles Are Differentially Regulated by a Carotenoid Isomerase-Mediated Abscisic Acid Pathway[OPEN

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Yin, Cui-Cui; Ma, Biao; Collinge, Derek Phillip; Pogson, Barry James; He, Si-Jie; Xiong, Qing; Duan, Kai-Xuan; Chen, Hui; Yang, Chao; Lu, Xiang; Wang, Yi-Qin; Zhang, Wan-Ke; Chu, Cheng-Cai; Sun, Xiao-Hong; Fang, Shuang; Chu, Jin-Fang; Lu, Tie-Gang; Chen, Shou-Yi; Zhang, Jin-Song

2015-01-01

Ethylene and abscisic acid (ABA) act synergistically or antagonistically to regulate plant growth and development. ABA is derived from the carotenoid biosynthesis pathway. Here, we analyzed the interplay among ethylene, carotenoid biogenesis, and ABA in rice (Oryza sativa) using the rice ethylene response mutant mhz5, which displays a reduced ethylene response in roots but an enhanced ethylene response in coleoptiles. We found that MHZ5 encodes a carotenoid isomerase and that the mutation in mhz5 blocks carotenoid biosynthesis, reduces ABA accumulation, and promotes ethylene production in etiolated seedlings. ABA can largely rescue the ethylene response of the mhz5 mutant. Ethylene induces MHZ5 expression, the production of neoxanthin, an ABA biosynthesis precursor, and ABA accumulation in roots. MHZ5 overexpression results in enhanced ethylene sensitivity in roots and reduced ethylene sensitivity in coleoptiles. Mutation or overexpression of MHZ5 also alters the expression of ethylene-responsive genes. Genetic studies revealed that the MHZ5-mediated ABA pathway acts downstream of ethylene signaling to inhibit root growth. The MHZ5-mediated ABA pathway likely acts upstream but negatively regulates ethylene signaling to control coleoptile growth. Our study reveals novel interactions among ethylene, carotenogenesis, and ABA and provides insight into improvements in agronomic traits and adaptive growth through the manipulation of these pathways in rice. PMID:25841037

Wnt/β-catenin signalling pathway mediated aberrant hippocampal neurogenesis in kainic acid-induced epilepsy.

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Qu, Zhengyi; Su, Fang; Qi, Xueting; Sun, Jianbo; Wang, Hongcai; Qiao, Zhenkui; Zhao, Hong; Zhu, Yulan

2017-10-01

Temporal lobe epilepsy is a chronic disorder of nerve system, mainly characterized by hippocampal sclerosis with massive neuronal loss and severe gliosis. Aberrant neurogenesis has been shown in the epileptogenesis process of temporal lobe epilepsy. However, the molecular mechanisms underlying aberrant neurogenesis remain unclear. The roles of Wnt signalling cascade have been well established in neurogenesis during multiple aspects. Here, we used kainic acid-induced rat epilepsy model to investigate whether Wnt/β-catenin signalling pathway is involved in the aberrant neurogenesis in temporal lobe epilepsy. Immunostaining and western blotting results showed that the expression levels of β-catenin, Wnt3a, and cyclin D1, the key regulators in Wnt signalling pathway, were up-regulated during acute epilepsy induced by the injection of kainic acids, indicating that Wnt signalling pathway was activated in kainic acid-induced temporal lobe epilepsy. Moreover, BrdU labelling results showed that blockade of the Wnt signalling by knocking down β-catenin attenuated aberrant neurogenesis induced by kainic acids injection. Altogether, Wnt/β-catenin signalling pathway mediated hippocampal neurogenesis during epilepsy, which might provide new strategies for clinical treatment of temporal lobe epilepsy. Temporal lobe epilepsy is a chronic disorder of nerve system, mainly characterized by hippocampal sclerosis. Aberrant neurogenesis has been shown to involve in the epileptogenesis process of temporal lobe epilepsy. In the present study, we discovered that Wnt3a/β-catenin signalling pathway serves as a link between aberrant neurogenesis and underlying remodelling in the hippocampus, leading to temporal lobe epilepsy, which might provide new strategies for clinical treatment of temporal lobe epilepsy. Copyright © 2017 John Wiley & Sons, Ltd.

Hepcidin mediates transcriptional changes that modulate acute cytokine-induced inflammatory responses in mice.

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De Domenico, Ivana; Zhang, Tian Y; Koening, Curry L; Branch, Ryan W; London, Nyall; Lo, Eric; Daynes, Raymond A; Kushner, James P; Li, Dean; Ward, Diane M; Kaplan, Jerry

2010-07-01

Hepcidin is a peptide hormone that regulates iron homeostasis and acts as an antimicrobial peptide. It is expressed and secreted by a variety of cell types in response to iron loading and inflammation. Hepcidin mediates iron homeostasis by binding to the iron exporter ferroportin, inducing its internalization and degradation via activation of the protein kinase Jak2 and the subsequent phosphorylation of ferroportin. Here we have shown that hepcidin-activated Jak2 also phosphorylates the transcription factor Stat3, resulting in a transcriptional response. Hepcidin treatment of ferroportin-expressing mouse macrophages showed changes in mRNA expression levels of a wide variety of genes. The changes in transcript levels for half of these genes were a direct effect of hepcidin, as shown by cycloheximide insensitivity, and dependent on the presence of Stat3. Hepcidin-mediated transcriptional changes modulated LPS-induced transcription in both cultured macrophages and in vivo mouse models, as demonstrated by suppression of IL-6 and TNF-alpha transcript and secreted protein. Hepcidin-mediated transcription in mice also suppressed toxicity and morbidity due to single doses of LPS, poly(I:C), and turpentine, which is used to model chronic inflammatory disease. Most notably, we demonstrated that hepcidin pretreatment protected mice from a lethal dose of LPS and that hepcidin-knockout mice could be rescued from LPS toxicity by injection of hepcidin. The results of our study suggest a new function for hepcidin in modulating acute inflammatory responses.

The possible mechanisms of protocatechuic acid-induced central analgesia

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Rana Arslan

2018-05-01

Full Text Available It is aimed to investigate the central antinociceptive effect of protocatechuic acid and the involvement of stimulation of opioidergic, serotonin 5-HT2A/2C, α2-adrenergic and muscarinic receptors in protocatechuic acid-induced central analgesia in mice. Time-dependent antinociceptive effects of protocatechuic acid at the oral doses of 75, 150 and 300 mg/kg were tested in hot-plate (integrated supraspinal response and tail-immersion (spinal reflex tests in mice. To investigate the mechanisms of action; the mice administered 300 mg/kg protocatechuic acid (p.o. were pre-treated with non-specific opioid antagonist naloxone (5 mg/kg, i.p., serotonin 5-HT2A/2C receptor antagonist ketanserin (1 mg/kg, i.p., α2-adrenoceptor antagonist yohimbine (1 mg/kg, i.p. and non-specific muscarinic antagonist atropine (5 mg/kg, i.p., respectively. The antinociceptive effect of protocatechuic acid was observed at the doses of 75, 150 and 300 mg/kg in tail-immersion test, at the doses of 150 and 300 mg/kg in hot-plate test at different time interval. The enhancement in the latency of protocatechuic acid-induced response to thermal stimuli was antagonized by yohimbine, naloxone and atropine in tail-immersion test, while it was antagonized only by yohimbine and naloxone pretreatments in hot-plate test. These results indicated that protocatechuic acid has the central antinociceptive action that is probably organized by spinal mediated cholinergic and opiodiergic, also spinal and supraspinal mediated noradrenergic modulation. However, further studies are required to understand how protocatechuic acid organizes the interactions of these modulatory systems. As a whole, these findings reinforce that protocatechuic acid is a potential agent that might be used for pain relief. Additionally, the clarification of the effect and mechanisms of action of protocatechuic acid will contribute to new therapeutic approaches and provide guidance for new drug

Circumvention of camptothecin-induced resistance during the adaptive cellular stress response.

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Tiligada, Ekaterini; Papamichael, Konstantinos; Vovou, Ioanna; Delitheos, Andreas

2006-01-01

Camptothecin-11 (CPT-11) induces the adaptive stress response in yeast, conferring resistance via not fully characterized mechanisms. This study aimed at exploring, pharmacologically, the mechanisms underlying the CPT-11-induced resistance in yeast. Post-logarithmic yeast cultures were submitted to heat shock following preconditioning with suramin and with CPT-11, either alone or in combination with suramin, cycloheximide, sodium molybdate, okadaic acid, or verapamil. The stress response was evaluated by determining cell viability after heat shock. Preconditioning with CPT-11 or suramin conferred thermotolerance to yeast cells. Co-administration of CPT-11 with suramin, cycloheximide or okadaic acid reversed the CPT-11-induced thermotolerant phenotype, while sodium molybdate and verapamil had no effect on CPT-11-induced resistance. The antagonistic effect of the thermotolerance-inducers and the possible contribution of topoisomerase II activity and post-translational modifications mediated by the phosphatases PP1/2A in CPT-11-induced resistance may have important implications on the acquisition of resistance to stress in eukaryotic cells.

Hepatitis C Virus Frameshift/Alternate Reading Frame Protein Suppresses Interferon Responses Mediated by Pattern Recognition Receptor Retinoic-Acid-Inducible Gene-I.

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Seung Bum Park

Full Text Available Hepatitis C virus (HCV actively evades host interferon (IFN responses but the mechanisms of how it does so are not completely understood. In this study, we present evidence for an HCV factor that contributes to the suppression of retinoic-acid-inducible gene-I (RIG-I-mediated IFN induction. Expression of frameshift/alternate reading frame protein (F/ARFP from HCV -2/+1 frame in Huh7 hepatoma cells suppressed type I IFN responses stimulated by HCV RNA pathogen-associated molecular pattern (PAMP and poly(IC. The suppression occurred independently of other HCV factors; and activation of interferon stimulated genes, TNFα, IFN-λ1, and IFN-λ2/3 was likewise suppressed by HCV F/ARFP. Point mutations in the full-length HCV sequence (JFH1 genotype 2a strain were made to introduce premature termination codons in the -2/+1 reading frame coding for F/ARFP while preserving the original reading frame, which enhanced IFNα and IFNβ induction by HCV. The potentiation of IFN response by the F/ARFP mutations was diminished in Huh7.5 cells, which already have a defective RIG-I, and by decreasing RIG-I expression in Huh7 cells. Furthermore, adding F/ARFP back via trans-complementation suppressed IFN induction in the F/ARFP mutant. The F/ARFP mutants, on the other hand, were not resistant to exogenous IFNα. Finally, HCV-infected human liver samples showed significant F/ARFP antibody reactivity, compared to HCV-uninfected control livers. Therefore, HCV F/ARFP likely cooperates with other viral factors to suppress type I and III IFN induction occurring through the RIG-I signaling pathway. This study identifies a novel mechanism of pattern recognition receptor modulation by HCV and suggests a biological function of the HCV alternate reading frame in the modulation of host innate immunity.

The promoter of the pepper pathogen-induced membrane protein gene CaPIMP1 mediates environmental stress responses in plants.

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Hong, Jeum Kyu; Hwang, Byung Kook

2009-01-01

The promoter of the pepper pathogen-induced membrane protein gene CaPIMP1 was analyzed by an Agrobacterium-mediated transient expression assay in tobacco leaves. Several stress-related cis-acting elements (GT-1, W-box and ABRE) are located within the CaPIMP1 promoter. In tobacco leaf tissues transiently transformed with a CaPIMP1 promoter-beta-glucuronidase (GUS) gene fusion, serially 5'-deleted CaPIMP1 promoters were differentially activated by Pseudomonas syringae pv. tabaci, ethylene, methyl jasmonate, abscisic acid, and nitric oxide. The -1,193 bp region of the CaPIMP1 gene promoter sequence exhibited full promoter activity. The -417- and -593 bp promoter regions were sufficient for GUS gene activation by ethylene and methyl jasmonate treatments, respectively. However, CaPIMP1 promoter sequences longer than -793 bp were required for promoter activation by abscisic acid and sodium nitroprusside treatments. CaPIMP1 expression was activated in pepper leaves by treatment with ethylene, methyl jasmonate, abscisic acid, beta-amino-n-butyric acid, NaCl, mechanical wounding, and low temperature, but not with salicylic acid. Overexpression of CaPIMP1 in Arabidopsis conferred hypersensitivity to mannitol, NaCl, and ABA during seed germination but not during seedling development. In contrast, transgenic plants overexpressing CaPIMP1 exhibited enhanced tolerance to oxidative stress induced by methyl viologen during germination and early seedling stages. These results suggest that CaPIMP1 expression may alter responsiveness to environmental stress, as well as to pathogen infection.

Folic acid and pantothenic acid protection against valproic acid-induced neural tube defects in CD-1 mice

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Dawson, Jennifer E [Department of Pharmacology and Toxicology and School of Environmental Studies, Queen' s University, Kingston, Ontario, K7L 3N6 (Canada); Raymond, Angela M [Department of Pharmacology and Toxicology and School of Environmental Studies, Queen' s University, Kingston, Ontario, K7L 3N6 (Canada); Winn, Louise M [Department of Pharmacology and Toxicology and School of Environmental Studies, Queen' s University, Kingston, Ontario, K7L 3N6 (Canada)

2006-03-01

In utero exposure to valproic acid (VPA) during pregnancy is associated with an increased risk of neural tube defects (NTDs). Although the mechanism by which VPA mediates these effects is unknown, VPA-initiated changes in embryonic protein levels have been implicated. The objectives of this study were to investigate the effect of in utero VPA exposure on embryonic protein levels of p53, NF-{kappa}B, Pim-1, c-Myb, Bax, and Bcl-2 in the CD-1 mouse. We also evaluated the protective effects of folic acid and pantothenic acid on VPA-induced NTDs and VPA-induced embryonic protein changes in this model. Pregnant CD-1 mice were administered a teratogenic dose of VPA prior to neural tube closure and embryonic protein levels were analyzed. In our study, VPA (400 mg/kg)-induced NTDs (24%) and VPA-exposed embryos with an NTD showed a 2-fold increase in p53, and 4-fold decreases in NF-{kappa}B, Pim-1, and c-Myb protein levels compared to their phenotypically normal littermates (P < 0.05). Additionally, VPA increased the ratio of embryonic Bax/Bcl-2 protein levels (P < 0.05). Pretreatment of pregnant dams with either folic acid or pantothenic acid prior to VPA significantly protected against VPA-induced NTDs (P < 0.05). Folic acid also reduced VPA-induced alterations in p53, NF-{kappa}B, Pim-1, c-Myb, and Bax/Bcl-2 protein levels, while pantothenic acid prevented VPA-induced alterations in NF-{kappa}B, Pim-1, and c-Myb. We hypothesize that folic acid and pantothenic acid protect CD-1 embryos from VPA-induced NTDs by independent, but not mutually exclusive mechanisms, both of which may be mediated by the prevention of VPA-induced alterations in proteins involved in neurulation.

A retinoic acid response element that overlaps an estrogen response element mediates multihormonal sensitivity in transcriptional activation of the lactoferrin gene.

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Lee, M O; Liu, Y; Zhang, X K

1995-08-01

The lactoferrin gene is highly expressed in many different tissues, and its expression is controlled by different regulators. In this report, we have defined a retinoic acid response element (RARE) in the 5'-flanking region of the lactoferrin gene promoter. The lactoferrin-RARE is composed of two AGGTCA-like motifs arranged as a direct repeat with 1-bp spacing (DR-1). A gel retardation assay demonstrated that it bound strongly with retinoid X receptor (RXR) homodimers and RXR-retinoic acid receptor (RAR) heterodimers as well as chicken ovalbumin upstream promoter transcription factor (COUP-TF) orphan receptor. In CV-1 cells, the lactoferrin-RARE linked with a heterologous thymidine kinase promoter was strongly activated by RXR homodimers in response to 9-cis-retinoic acid (9-cis-RA) but not to all-trans-RA. When the COUP-TF orphan receptor was cotransfected, the 9-cis-RA-induced RXR homodimer activity was strongly repressed. A unique feature of the lactoferrin-RARE is that it has an AGGTCA-like motif in common with an estrogen-responsive element (ERE). The composite RARE/ERE contributes to the functional interaction between retinoid receptors and the estrogen receptor (ER) and their ligands. In CV-1 cells, cotransfection of the retinoid and estrogen receptors led to mutual inhibition of the other's activity, while an RA-dependent inhibition of ER activity was observed in breast cancer cells. Furthermore, the lactoferrin-RARE/ERE showed differential transactivation activity in different cell types. RAs could activate the lactoferrin-RARE/ERE in human leukemia HL-60 cells and U937 cells but not in human breast cancer cells. By gel retardation analyses, we demonstrated that strong binding of the endogenous COUP-TF in breast cancer cells to the composite element contributed to diminished RA response in these cells. Thus, the lactoferrin-RARE/ERE functions as a signaling switch module that mediates multihormonal responsiveness in the regulation of lactoferrin gene

In Silico Identification of Mimicking Molecules as Defense Inducers Triggering Jasmonic Acid Mediated Immunity against Alternaria Blight Disease in Brassica Species

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Dinesh Pandey

2017-04-01

Full Text Available Alternaria brassicae and Alternaria brassicicola are two major phytopathogenic fungi which cause Alternaria blight, a recalcitrant disease on Brassica crops throughout the world, which is highly destructive and responsible for significant yield losses. Since no resistant source is available against Alternaria blight, therefore, efforts have been made in the present study to identify defense inducer molecules which can induce jasmonic acid (JA mediated defense against the disease. It is believed that JA triggered defense response will prevent necrotrophic mode of colonization of Alternaria brassicae fungus. The JA receptor, COI1 is one of the potential targets for triggering JA mediated immunity through interaction with JA signal. In the present study, few mimicking compounds more efficient than naturally occurring JA in terms of interaction with COI1 were identified through virtual screening and molecular dynamics simulation studies. A high quality structural model of COI1 was developed using the protein sequence of Brassica rapa. This was followed by virtual screening of 767 analogs of JA from ZINC database for interaction with COI1. Two analogs viz. ZINC27640214 and ZINC43772052 showed more binding affinity with COI1 as compared to naturally occurring JA. Molecular dynamics simulation of COI1 and COI1-JA complex, as well as best screened interacting structural analogs of JA with COI1 was done for 50 ns to validate the stability of system. It was found that ZINC27640214 possesses efficient, stable, and good cell permeability properties. Based on the obtained results and its physicochemical properties, it is capable of mimicking JA signaling and may be used as defense inducers for triggering JA mediated resistance against Alternaria blight, only after further validation through field trials.

Antagonizing Effects of Aspartic Acid against Ultraviolet A-Induced Downregulation of the Stemness of Human Adipose Tissue-Derived Mesenchymal Stem Cells.

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Kwangseon Jung

Full Text Available Ultraviolet A (UVA irradiation is responsible for a variety of changes in cell biology. The purpose of this study was to investigate effects of aspartic acid on UVA irradiation-induced damages in the stemness properties of human adipose tissue-derived mesenchymal stem cells (hAMSCs. Furthermore, we elucidated the UVA-antagonizing mechanisms of aspartic acid. The results of this study showed that aspartic acid attenuated the UVA-induced reduction of the proliferative potential and stemness of hAMSCs, as evidenced by increased proliferative activity in the 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay and upregulation of stemness-related genes OCT4, NANOG, and SOX2 in response to the aspartic acid treatment. UVA-induced reduction in the mRNA level of hypoxia-inducible factor (HIF-1α was also significantly recovered by aspartic acid. In addition, the antagonizing effects of aspartic acid against the UVA effects were found to be mediated by reduced production of PGE2 through the inhibition of JNK and p42/44 MAPK. Taken together, these findings show that aspartic acid improves reduced stemness of hAMSCs induced by UVA and its effects are mediated by upregulation of HIF-1α via the inhibition of PGE2-cAMP signaling. In addition, aspartic acid may be used as an antagonizing agent to mitigate the effects of UVA.

Antagonizing Effects of Aspartic Acid against Ultraviolet A-Induced Downregulation of the Stemness of Human Adipose Tissue-Derived Mesenchymal Stem Cells.

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Jung, Kwangseon; Cho, Jae Youl; Soh, Young-Jin; Lee, Jienny; Shin, Seoung Woo; Jang, Sunghee; Jung, Eunsun; Kim, Min Hee; Lee, Jongsung

2015-01-01

Ultraviolet A (UVA) irradiation is responsible for a variety of changes in cell biology. The purpose of this study was to investigate effects of aspartic acid on UVA irradiation-induced damages in the stemness properties of human adipose tissue-derived mesenchymal stem cells (hAMSCs). Furthermore, we elucidated the UVA-antagonizing mechanisms of aspartic acid. The results of this study showed that aspartic acid attenuated the UVA-induced reduction of the proliferative potential and stemness of hAMSCs, as evidenced by increased proliferative activity in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and upregulation of stemness-related genes OCT4, NANOG, and SOX2 in response to the aspartic acid treatment. UVA-induced reduction in the mRNA level of hypoxia-inducible factor (HIF)-1α was also significantly recovered by aspartic acid. In addition, the antagonizing effects of aspartic acid against the UVA effects were found to be mediated by reduced production of PGE2 through the inhibition of JNK and p42/44 MAPK. Taken together, these findings show that aspartic acid improves reduced stemness of hAMSCs induced by UVA and its effects are mediated by upregulation of HIF-1α via the inhibition of PGE2-cAMP signaling. In addition, aspartic acid may be used as an antagonizing agent to mitigate the effects of UVA.

Effect of amiloride on experimental acid-induced heartburn in non-erosive reflux disease.

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Bulsiewicz, William J; Shaheen, Nicholas J; Hansen, Mark B; Pruitt, Amy; Orlando, Roy C

2013-07-01

Acid-sensing ion channels (ASICs) are esophageal nociceptors that are candidates to mediate heartburn in non-erosive reflux disease (NERD). Amiloride, a diuretic, is known to inhibit ASICs. For this reason, we sought a role for ASICs in mediating heartburn by determining whether amiloride could block heartburn in NERD induced by esophageal acid perfusion. In a randomized double-blind crossover study, we perfused the esophagus with amiloride or (saline) placebo prior to eliciting acid-induced heartburn in patients with a history of proton pump inhibitor-responsive NERD. Those with NERD and positive modified Bernstein test were randomized to perfusion with amiloride, 1 mmol/l, or placebo for 5 min, followed by repeat acid-perfusion. Heartburn severity and time to onset was measured and the process repeated following crossover to the alternative agent. 14 subjects completed the study. Amiloride did not reduce the frequency (100 vs. 100 %) or severity of acid-induced heartburn (Mean 2.50 ± SEM 0.33 vs. 2.64 ± 0.45), respectively. There was a trend towards longer time to onset of heartburn for amiloride versus placebo (Mean 2.93 ± SEM 0.3 vs. 2.36 ± 0.29 min, respectively), though these differences did not reach statistical significance (p > 0.05). Amiloride had no significant effect on acid-induced heartburn frequency or severity in NERD, although there was a trend towards prolonged time to onset of symptoms.

Deer Bone Oil Extract Suppresses Lipopolysaccharide-Induced Inflammatory Responses in RAW264.7 Cells.

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Choi, Hyeon-Son; Im, Suji; Park, Yooheon; Hong, Ki-Bae; Suh, Hyung Joo

2016-01-01

The aim of this study was to investigate the effect of deer bone oil extract (DBOE) on lipopolysaccharide (LPS)-induced inflammatory responses in RAW264.7 cells. DBOE was fractionated by liquid-liquid extraction to obtain two fractions: methanol fraction (DBO-M) and hexane fraction (DBO-H). TLC showed that DBO-M had relatively more hydrophilic lipid complexes, including unsaturated fatty acids, than DBOE and DBO-H. The relative compositions of tetradecenoyl carnitine, α-linoleic acid, and palmitoleic acid increased in the DBO-M fraction by 61, 38, and 32%, respectively, compared with DBOE. The concentration of sugar moieties was 3-fold higher in the DBO-M fraction than DBOE and DBO-H. DBO-M significantly decreased LPS-induced nitric oxide (NO) production in RAW264.7 cells in a dose-dependent manner. This DBO-M-mediated decrease in NO production was due to downregulation of mRNA and protein levels of inducible nitric oxide synthase (iNOS). In addition, mRNA expression of pro-inflammatory mediators, such as cyclooxygenase (COX-2), interleukin (IL)-1β, and IL-12β, was suppressed by DBO-M. Our data showed that DBO-M, which has relatively higher sugar content than DBOE and DBO-H, could play an important role in suppressing inflammatory responses by controlling pro-inflammatory cytokines and mediators.

Rho Kinase ROCK2 Mediates Acid-Induced NADPH Oxidase NOX5-S Expression in Human Esophageal Adenocarcinoma Cells.

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Jie Hong

Full Text Available Mechanisms of the progression from Barrett's esophagus (BE to esophageal adenocarcinoma (EA are not fully understood. We have shown that NOX5-S may be involved in this progression. However, how acid upregulates NOX5-S is not well known. We found that acid-induced increase in NOX5-S expression was significantly decreased by the Rho kinase (ROCK inhibitor Y27632 in BE mucosal biopsies and FLO-1 EA cells. In addition, acid treatment significantly increased the Rho kinase activity in FLO-1 cells. The acid-induced increase in NOX5-S expression and H2O2 production was significantly decreased by knockdown of Rho kinase ROCK2, but not by knockdown of ROCK1. Conversely, the overexpression of the constitutively active ROCK2, but not the constitutively active ROCK1, significantly enhanced the NOX5-S expression and H2O2 production. Moreover, the acid-induced increase in Rho kinase activity and in NOX5-S mRNA expression was blocked by the removal of calcium in both FLO-1 and OE33 cells. The calcium ionophore A23187 significantly increased the Rho kinase activity and NOX5-S mRNA expression. We conclude that acid-induced increase in NOX5-S expression and H2O2 production may depend on the activation of ROCK2, but not ROCK1, in EA cells. The acid-induced activation of Rho kinase may be mediated by the intracellular calcium increase. It is possible that persistent acid reflux present in BE patients may increase the intracellular calcium, activate ROCK2 and thereby upregulate NOX5-S. High levels of reactive oxygen species derived from NOX5-S may cause DNA damage and thereby contribute to the progression from BE to EA.

Disruption of Ethylene Responses by Turnip mosaic virus Mediates Suppression of Plant Defense against the Green Peach Aphid Vector.

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Casteel, Clare L; De Alwis, Manori; Bak, Aurélie; Dong, Haili; Whitham, Steven A; Jander, Georg

2015-09-01

Plants employ diverse responses mediated by phytohormones to defend themselves against pathogens and herbivores. Adapted pathogens and herbivores often manipulate these responses to their benefit. Previously, we demonstrated that Turnip mosaic virus (TuMV) infection suppresses callose deposition, an important plant defense induced in response to feeding by its aphid vector, the green peach aphid (Myzus persicae), and increases aphid fecundity compared with uninfected control plants. Further, we determined that production of a single TuMV protein, Nuclear Inclusion a-Protease (NIa-Pro) domain, was responsible for changes in host plant physiology and increased green peach aphid reproduction. To characterize the underlying molecular mechanisms of this phenomenon, we examined the role of three phytohormone signaling pathways, jasmonic acid, salicylic acid, and ethylene (ET), in TuMV-infected Arabidopsis (Arabidopsis thaliana), with or without aphid herbivory. Experiments with Arabidopsis mutants ethylene insensitive2 and ethylene response1, and chemical inhibitors of ET synthesis and perception (aminoethoxyvinyl-glycine and 1-methylcyclopropene, respectively), show that the ET signaling pathway is required for TuMV-mediated suppression of Arabidopsis resistance to the green peach aphid. Additionally, transgenic expression of NIa-Pro in Arabidopsis alters ET responses and suppresses aphid-induced callose formation in an ET-dependent manner. Thus, disruption of ET responses in plants is an additional function of NIa-Pro, a highly conserved potyvirus protein. Virus-induced changes in ET responses may mediate vector-plant interactions more broadly and thus represent a conserved mechanism for increasing transmission by insect vectors across generations. © 2015 American Society of Plant Biologists. All Rights Reserved.

Allergen-Induced Dermatitis Causes Alterations in Cutaneous Retinoid-Mediated Signaling in Mice

Science.gov (United States)

Gericke, Janine; Ittensohn, Jan; Mihály, Johanna; Dubrac, Sandrine; Rühl, Ralph

2013-01-01

Nuclear receptor-mediated signaling via RARs and PPARδ is involved in the regulation of skin homeostasis. Moreover, activation of both RAR and PPARδ was shown to alter skin inflammation. Endogenous all-trans retinoic acid (ATRA) can activate both receptors depending on specific transport proteins: Fabp5 initiates PPARδ signaling whereas Crabp2 promotes RAR signaling. Repetitive topical applications of ovalbumin (OVA) in combination with intraperitoneal injections of OVA or only intraperitoneal OVA applications were used to induce allergic dermatitis. In our mouse model, expression of IL-4, and Hbegf increased whereas expression of involucrin, Abca12 and Spink5 decreased in inflamed skin, demonstrating altered immune response and epidermal barrier homeostasis. Comprehensive gene expression analysis showed alterations of the cutaneous retinoid metabolism and retinoid-mediated signaling in allergic skin immune response. Notably, ATRA synthesis was increased as indicated by the elevated expression of retinaldehyde dehydrogenases and increased levels of ATRA. Consequently, the expression pattern of genes downstream to RAR was altered. Furthermore, the increased ratio of Fabp5 vs. Crabp2 may indicate an up-regulation of the PPARδ pathway in allergen-induced dermatitis in addition to the altered RAR signaling. Thus, our findings suggest that ATRA levels, RAR-mediated signaling and signaling involved in PPARδ pathways are mainly increased in allergen-induced dermatitis and may contribute to the development and/or maintenance of allergic skin diseases. PMID:23977003

Gallic acid abolishes the EGFR/Src/Akt/Erk-mediated expression of matrix metalloproteinase-9 in MCF-7 breast cancer cells.

Science.gov (United States)

Chen, Ying-Jung; Lin, Ku-Nan; Jhang, Li-Mei; Huang, Chia-Hui; Lee, Yuan-Chin; Chang, Long-Sen

2016-05-25

Several studies have revealed that natural compounds are valuable resources to develop novel agents against dysregulation of the EGF/EGFR-mediated matrix metalloproteinase-9 (MMP-9) expression in cancer cells. In view of the findings that EGF/EGFR-mediated MMP-9 expression is closely related to invasion and metastasis of breast cancer. To determine the beneficial effects of gallic acid on the suppression of breast cancer metastasis, we explored the effect of gallic acid on MMP-9 expression in EGF-treated MCF-7 breast cancer cells. Treatment with EGF up-regulated MMP-9 mRNA and protein levels in MCF-7 cells. EGF treatment induced phosphorylation of EGFR and elicited Src activation, subsequently promoting Akt/NFκB (p65) and ERK/c-Jun phosphorylation in MCF-7 cells. Activation of Akt/p65 and ERK/c-Jun was responsible for the MMP-9 up-regulation in EGF-treated cells. Gallic acid repressed the EGF-induced activation of EGFR and Src; furthermore, inactivation of Akt/p65 and ERK/c-Jun was a result of the inhibitory effect of gallic acid on the EGF-induced MMP-9 up-regulation. Over-expression of constitutively active Akt and MEK1 or over-expression of constitutively active Src eradicated the inhibitory effect of gallic acid on the EGF-induced MMP-9 up-regulation. A chromosome conformation capture assay showed that EGF induced a chromosomal loop formation in the MMP-9 promoter via NFκB/p65 and AP-1/c-Jun activation. Treatment with gallic acid, EGFR inhibitor, or Src inhibitor reduced DNA looping. Taken together, our data suggest that gallic acid inhibits the activation of EGFR/Src-mediated Akt and ERK, leading to reduced levels of p65/c-Jun-mediated DNA looping and thus inhibiting MMP-9 expression in EGF-treated MCF-7 cells. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Nitro-fatty acids in plant signaling: New key mediators of nitric oxide metabolism

Directory of Open Access Journals (Sweden)

Capilla Mata-Pérez

2017-04-01

Full Text Available Recent studies in animal systems have shown that NO can interact with fatty acids to generate nitro-fatty acids (NO2-FAs. They are the product of the reaction between reactive nitrogen species and unsaturated fatty acids, and are considered novel mediators of cell signaling based mainly on a proven anti-inflammatory response. Although these signaling mediators have been described widely in animal systems, NO2-FAs have scarcely been studied in plants. Preliminary data have revealed the endogenous presence of free and protein-adducted NO2-FAs in extra-virgin olive oil (EVOO, which appear to be contributing to the cardiovascular benefits associated with the Mediterranean diet. Importantly, new findings have displayed the endogenous occurrence of nitro-linolenic acid (NO2-Ln in the model plant Arabidopsis thaliana and the modulation of NO2-Ln levels throughout this plant's development. Furthermore, a transcriptomic analysis by RNA-seq technology established a clear signaling role for this molecule, demonstrating that NO2-Ln was involved in plant-defense response against different abiotic-stress conditions, mainly by inducing the chaperone network and supporting a conserved mechanism of action in both animal and plant defense processes. Thus, NO2-Ln levels significantly rose under several abiotic-stress conditions, highlighting the strong signaling role of these molecules in the plant-protection mechanism. Finally, the potential of NO2-Ln as a NO donor has recently been described both in vitro and in vivo. Jointly, this ability gives NO2-Ln the potential to act as a signaling molecule by the direct release of NO, due to its capacity to induce different changes mediated by NO or NO-related molecules such as nitration and S-nitrosylation, or by the electrophilic capacity of these molecules through a nitroalkylation mechanism. Here, we describe the current state of the art regarding the advances performed in the field of NO2-FAs in plants and their

[Tranexamic acid as first-line emergency treatment for episodes of bradykinin-mediated angioedema induced by ACE inhibitors].

Science.gov (United States)

Beauchêne, C; Martins-Héricher, J; Denis, D; Martin, L; Maillard, H

2018-05-04

Episodes of acquired bradykinin-mediated angioedema due to angiotensin-converting enzyme (ACE) inhibitors may result in fatal outcomes. There is no consensus regarding emergency pharmacological management of these episodes. Treatment options include icatibant and C1INH concentrate. Tranexamic acid is administered for moderate episodes. Its efficacy in the treatment of ACE inhibitor-induced episodes of angioedema is not established. The aim of this retrospective study is to assess the benefits of emergency tranexamic acid administration in the management of ACE inhibitor-induced episodes of angioedema. Retrospective analysis of the medical files of patients who consulted between 2010 and 2016 in two French tertiary care hospitals for a bradykinic angioedema attributed to an ACE treatment. All of them had received tranexamic acid as a first line treatment. Thirty three patients who had experienced severe episode of angioedema were included. Twenty seven patients showed significant improvement when treated with tranexamic acid alone. The six remaining patients were treated with icatibant (5/33) or C1INH concentrate (1/33), due to partial improvement after tranexamic acid therapy. None of the patients were intubated, no fatalities were recorded and no side effects were reported. Tranexamic acid is an easily accessible and affordable therapy that may provide effective treatment for ACE inhibitor-induced episodes of angioedema. It may help while waiting for a more specific treatment (icatibant and C1INH concentrate) that is at times unavailable in emergency departments. Copyright © 2018 Société Nationale Française de Médecine Interne (SNFMI). Published by Elsevier SAS. All rights reserved.

Acetylsalicylic acid inhibits IL-18-induced cardiac fibroblast migration through the induction of RECK.

Science.gov (United States)

Siddesha, Jalahalli M; Valente, Anthony J; Sakamuri, Siva S V P; Gardner, Jason D; Delafontaine, Patrice; Noda, Makoto; Chandrasekar, Bysani

2014-07-01

The pathogenesis of cardiac fibrosis and adverse remodeling is thought to involve the ROS-dependent induction of inflammatory cytokines and matrix metalloproteinases (MMPs), and the activation and migration of cardiac fibroblasts (CF). Here we investigated the role of RECK (reversion-inducing-cysteine-rich protein with Kazal motifs), a unique membrane-anchored MMP regulator, on IL-18-induced CF migration, and the effect of acetylsalicylic acid (ASA) on this response. In a Matrigel invasion assay, IL-18-induced migration of primary mouse CF was dependent on both IKK/NF-κB- and JNK/AP-1-mediated MMP9 induction and Sp1-mediated RECK suppression, mechanisms that required Nox4-dependent H(2)O(2) generation. Notably, forced expression of RECK attenuated IL-18-induced MMP9 activation and CF migration. Further, therapeutic concentrations of ASA inhibited IL-18-induced H(2)O(2) generation, MMP9 activation, RECK suppression, and CF migration. The salicylic acid moiety of ASA similarly attenuated IL-18-induced CF migration. Thus, ASA may exert potential beneficial effect in cardiac fibrosis through multiple protective mechanisms. © 2013 Wiley Periodicals, Inc.

Valproate induced hepatic steatosis by enhanced fatty acid uptake and triglyceride synthesis

International Nuclear Information System (INIS)

Bai, Xupeng; Hong, Weipeng; Cai, Peiheng; Chen, Yibei; Xu, Chuncao; Cao, Di; Yu, Weibang; Zhao, Zhongxiang; Huang, Min; Jin, Jing

2017-01-01

Steatosis is the characteristic type of VPA-induced hepatotoxicity and may result in life-threatening hepatic lesion. Approximately 61% of patients treated with VPA have been diagnosed with hepatic steatosis through ultrasound examination. However, the mechanisms underlying VPA-induced intracellular fat accumulation are not yet fully understood. Here we demonstrated the involvement of fatty acid uptake and lipogenesis in VPA-induced hepatic steatosis in vitro and in vivo by using quantitative real-time PCR (qRT-PCR) analysis, western blotting analysis, fatty acid uptake assays, Nile Red staining assays, and Oil Red O staining assays. Specifically, we found that the expression of cluster of differentiation 36 (CD36), an important fatty acid transport, and diacylglycerol acyltransferase 2 (DGAT2) were significantly up-regulated in HepG2 cells and livers of C57B/6J mice after treatment with VPA. Furthermore, VPA treatment remarkably enhanced the efficiency of fatty acid uptake mediated by CD36, while this effect was abolished by the interference with CD36-specific siRNA. Also, VPA treatment significantly increased DGAT2 expression as a result of the inhibition of mitogen-activated protein kinase kinase (MEK) – extracellular regulated kinase (ERK) pathway; however, DGAT2 knockdown significantly alleviated VPA-induced intracellular lipid accumulation. Additionally, we also found that sterol regulatory element binding protein-1c (SREBP-1c)-mediated fatty acid synthesis may be not involved in VPA-induced hepatic steatosis. Overall, VPA-triggered over-regulation of CD36 and DGAT2 could be helpful for a better understanding of the mechanisms underlying VPA-induced hepatic steatosis and may offer novel therapeutic strategies to combat VPA-induced hepatotoxicity. - Highlights: • VPA induced hepatic steatosis and modulated genes associated with lipid metabolism. • CD36-mediated fatty acid uptake contributed to VPA-induced lipid accumulation. • PA increased the hepatic

Valproate induced hepatic steatosis by enhanced fatty acid uptake and triglyceride synthesis

Energy Technology Data Exchange (ETDEWEB)

Bai, Xupeng; Hong, Weipeng; Cai, Peiheng; Chen, Yibei; Xu, Chuncao [School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou (China); Cao, Di [School of Chinese Materia Medica, Guangzhou University of Chinese Medicine, Guangzhou (China); Yu, Weibang [School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou (China); Zhao, Zhongxiang [School of Chinese Materia Medica, Guangzhou University of Chinese Medicine, Guangzhou (China); Huang, Min [School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou (China); Jin, Jing, E-mail: jinjing@mail.sysu.edu.cn [School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou (China)

2017-06-01

Steatosis is the characteristic type of VPA-induced hepatotoxicity and may result in life-threatening hepatic lesion. Approximately 61% of patients treated with VPA have been diagnosed with hepatic steatosis through ultrasound examination. However, the mechanisms underlying VPA-induced intracellular fat accumulation are not yet fully understood. Here we demonstrated the involvement of fatty acid uptake and lipogenesis in VPA-induced hepatic steatosis in vitro and in vivo by using quantitative real-time PCR (qRT-PCR) analysis, western blotting analysis, fatty acid uptake assays, Nile Red staining assays, and Oil Red O staining assays. Specifically, we found that the expression of cluster of differentiation 36 (CD36), an important fatty acid transport, and diacylglycerol acyltransferase 2 (DGAT2) were significantly up-regulated in HepG2 cells and livers of C57B/6J mice after treatment with VPA. Furthermore, VPA treatment remarkably enhanced the efficiency of fatty acid uptake mediated by CD36, while this effect was abolished by the interference with CD36-specific siRNA. Also, VPA treatment significantly increased DGAT2 expression as a result of the inhibition of mitogen-activated protein kinase kinase (MEK) – extracellular regulated kinase (ERK) pathway; however, DGAT2 knockdown significantly alleviated VPA-induced intracellular lipid accumulation. Additionally, we also found that sterol regulatory element binding protein-1c (SREBP-1c)-mediated fatty acid synthesis may be not involved in VPA-induced hepatic steatosis. Overall, VPA-triggered over-regulation of CD36 and DGAT2 could be helpful for a better understanding of the mechanisms underlying VPA-induced hepatic steatosis and may offer novel therapeutic strategies to combat VPA-induced hepatotoxicity. - Highlights: • VPA induced hepatic steatosis and modulated genes associated with lipid metabolism. • CD36-mediated fatty acid uptake contributed to VPA-induced lipid accumulation. • PA increased the hepatic

Human inflammatory and resolving lipid mediator responses to resistance exercise and ibuprofen treatment

Science.gov (United States)

Markworth, James F.; Vella, Luke; Lingard, Benjamin S.; Tull, Dedreia L.; Rupasinghe, Thusitha W.; Sinclair, Andrew J.; Maddipati, Krishna Rao

2013-01-01

Classical proinflammatory eicosanoids, and more recently discovered lipid mediators with anti-inflammatory and proresolving bioactivity, exert a complex role in the initiation, control, and resolution of inflammation. Using a targeted lipidomics approach, we investigated circulating lipid mediator responses to resistance exercise and treatment with the NSAID ibuprofen. Human subjects undertook a single bout of unaccustomed resistance exercise (80% of one repetition maximum) following oral ingestion of ibuprofen (400 mg) or placebo control. Venous blood was collected during early recovery (0–3 h and 24 h postexercise), and serum lipid mediator composition was analyzed by LC-MS-based targeted lipidomics. Postexercise recovery was characterized by elevated levels of cyclooxygenase (COX)-1 and 2-derived prostanoids (TXB2, PGE2, PGD2, PGF2α, and PGI2), lipooxygenase (5-LOX, 12-LOX, and 15-LOX)-derived hydroxyeicosatetraenoic acids (HETEs), and leukotrienes (e.g., LTB4), and epoxygenase (CYP)-derived epoxy/dihydroxy eicosatrienoic acids (EpETrEs/DiHETrEs). Additionally, we detected elevated levels of bioactive lipid mediators with anti-inflammatory and proresolving properties, including arachidonic acid-derived lipoxins (LXA4 and LXB4), and the EPA (E-series) and DHA (D-series)-derived resolvins (RvD1 and RvE1), and protectins (PD1 isomer 10S, 17S-diHDoHE). Ibuprofen treatment blocked exercise-induced increases in COX-1 and COX-2-derived prostanoids but also resulted in off-target reductions in leukotriene biosynthesis, and a diminished proresolving lipid mediator response. CYP pathway product metabolism was also altered by ibuprofen treatment, as indicated by elevated postexercise serum 5,6-DiHETrE and 8,9-DiHETrE only in those receiving ibuprofen. These findings characterize the blood inflammatory lipid mediator response to unaccustomed resistance exercise in humans and show that acute proinflammatory signals are mechanistically linked to the induction of a

Acidic environment augments FcεRI-mediated production of IL-6 and IL-13 in mast cells

Energy Technology Data Exchange (ETDEWEB)

Kamide, Yosuke, E-mail: m08702012@gunma-u.ac.jp [Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi (Japan); Clinical Research Center for Allergy and Rheumatology, Sagamihara National Hospital, Sagamihara (Japan); Ishizuka, Tamotsu [Third Department of Internal Medicine, Faculty of Medical Sciences, University of Fukui, Fukui (Japan); Tobo, Masayuki [Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi (Japan); Tsurumaki, Hiroaki [Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi (Japan); Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi (Japan); Aoki, Haruka; Mogi, Chihiro [Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi (Japan); Nakakura, Takashi [Department of Anatomy, Graduate School of Medicine, Teikyo University, Tokyo (Japan); Yatomi, Masakiyo; Ono, Akihiro; Koga, Yasuhiko [Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi (Japan); Sato, Koichi [Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi (Japan); Hisada, Takeshi [Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi (Japan); Dobashi, Kunio [Gunma University Graduate School of Health Sciences, Maebashi (Japan); Yamada, Masanobu [Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi (Japan); Okajima, Fumikazu [Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi (Japan)

2015-08-28

Although blood pH is maintained in a narrow range of around pH 7.4 in living organisms, inflammatory loci are characterized by acidic conditions. Mast cells tend to reside close to the surface of the body in areas such as the mucosa and skin where they may be exposed to exogenous acids, and they play an important role in immune responses. However, little is known about the effects of extracellular acidification on the functions of mast cell. Here, we found that extracellular acidification increased the dinitrophenyl-conjugated human serum albumin (DNP-HSA)-induced production of interleukin (IL)-6 and IL-13 in MC/9 cells or bone marrow-derived mouse mast cells sensitized with anti-DNP IgE. Extracellular acidification also inhibited migration of MC/9 cells toward DNP-HSA. In addition, acidic pH stimulated antigen-induced activation of p38 mitogen-activated protein kinase (MAPK) and protein kinase B (Akt). These findings suggest that extracellular acidification augmented antigen/IgE-induced and FcεRI-mediated production of IL-6 and IL-13 in mast cells, and that this was associated with the enhancement of p38 MAPK and Akt activation. - Highlights: • Antigen-induced IL-6 and IL-13 production was augmented by acidic pH in mast cells. • Acidic pH-induced actions were associated with activation of p38 MAPK and Akt. • Inhibition of p38 MAPK and Akt attenuated cytokine responses to acidic pH. • Acidic pH effects are not attributable to actions of known proton-sensing GPCRs.

Ethylene signaling renders the jasmonate response of Arabidopsis insensitive to future suppression by salicylic acid

OpenAIRE

Leon Reyes, H.A.; Du, Y.; Koornneef, A.; Proietti, S.; Körbes, A.P.; Memelink, J.; Pieterse, C.M.J.; Ritsema, T.

2010-01-01

Cross-talk between jasmonate (JA), ethylene (ET), and Salicylic acid (SA) signaling is thought to operate as a mechanism to fine-tune induced defenses that are activated in response to multiple attackers. Here, 43 Arabidopsis genotypes impaired in hormone signaling or defense-related processes were screened for their ability to express SA-mediated suppression of JA-responsive gene expression. Mutant cev1, which displays constitutive expression of JA and ET responses, appeared to be insensitiv...

CD14 is a key mediator of both lysophosphatidic acid and lipopolysaccharide induction of foam cell formation.

Science.gov (United States)

An, Dong; Hao, Feng; Zhang, Fuqiang; Kong, Wei; Chun, Jerold; Xu, Xuemin; Cui, Mei-Zhen

2017-09-01

Macrophage uptake of oxidized low-density lipoprotein (oxLDL) plays an important role in foam cell formation and the pathogenesis of atherosclerosis. We report here that lysophosphatidic acid (LPA) enhances lipopolysaccharide (LPS)-induced oxLDL uptake in macrophages. Our data revealed that both LPA and LPS highly induce the CD14 expression at messenger RNA and protein levels in macrophages. The role of CD14, one component of the LPS receptor cluster, in LPA-induced biological functions has been unknown. We took several steps to examine the role of CD14 in LPA signaling pathways. Knockdown of CD14 expression nearly completely blocked LPA/LPS-induced oxLDL uptake in macrophages, demonstrating for the first time that CD14 is a key mediator responsible for both LPA- and LPS-induced oxLDL uptake/foam cell formation. To determine the molecular mechanism mediating CD14 function, we demonstrated that both LPA and LPS significantly induce the expression of scavenger receptor class A type I (SR-AI), which has been implicated in lipid uptake process, and depletion of CD14 levels blocked LPA/LPS-induced SR-AI expression. We further showed that the SR-AI-specific antibody, which quenches SR-AI function, blocked LPA- and LPS-induced foam cell formation. Thus, SR-AI is the downstream mediator of CD14 in regulating LPA-, LPS-, and LPA/LPS-induced foam cell formation. Taken together, our results provide the first experimental evidence that CD14 is a novel connecting molecule linking both LPA and LPS pathways and is a key mediator responsible for LPA/LPS-induced foam cell formation. The LPA/LPS-CD14-SR-AI nexus might be the new convergent pathway, contributing to the worsening of atherosclerosis. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Gallic Acid Induces Apoptosis in Human Gastric Adenocarcinoma Cells.

Science.gov (United States)

Tsai, Chung-Lin; Chiu, Ying-Ming; Ho, Tin-Yun; Hsieh, Chin-Tung; Shieh, Dong-Chen; Lee, Yi-Ju; Tsay, Gregory J; Wu, Yi-Ying

2018-04-01

Gastric cancer is one of the most common malignant cancers with a poor prognosis and high mortality rate worldwide. Current treatment of gastric cancer includes surgery and chemotherapy as the main modalities, but the potentially severe side-effects of chemotherapy present a considerable challenge. Gallic acid is a trihydroxybenzoic acid found to exert an anticancer effect against a variety of cancer cells. The purpose of this study was to determine the anti-cancer activity of Galla chinensis and its main component gallic acid on human gastric adenocarcinoma cells. MTT assay and cell death ELISA were used to determine the apoptotic effect of Gallic Chinensis and gallic acid on human gastric adenocarcinoma cells. To determine the pathway and relevant components by which gallic acid-induced apoptosis is mediated through, cells were transfected with siRNA (Fas, FasL, DR5, p53) using Lipofectamine 2000. Reults: Gallic Chinensis and gallic acid induced apoptosis of human gastric adenocarcinoma cells. Gallic acid induced up-regulation of Fas, FasL, and DR5 expression in AGS cells. Transfection of cells with Fas, FasL, or DR5 siRNA reduced gallic acid-induced cell death. In addition, p53 was shown to be involved in gallic acid-mediated Fas, FasL, and DR5 expression as well as cell apoptosis in AGS cells. These results suggest that gallic acid has a potential role in the treatment of gastric cancer. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Jasmonic acid-mediated defense suppresses brassinosteroid-mediated susceptibility to Rice black streaked dwarf virus infection in rice.

Science.gov (United States)

He, Yuqing; Zhang, Hehong; Sun, Zongtao; Li, Junmin; Hong, Gaojie; Zhu, Qisong; Zhou, Xuebiao; MacFarlane, Stuart; Yan, Fei; Chen, Jianping

2017-04-01

Plant hormones play a vital role in plant immune responses. However, in contrast to the relative wealth of information on hormone-mediated immunity in dicot plants, little information is available on monocot-virus defense systems. We used a high-throughput-sequencing approach to compare the global gene expression of Rice black-streaked dwarf virus (RBSDV)-infected rice plants with that of healthy plants. Exogenous hormone applications and transgenic rice were used to test RBSDV infectivity and pathogenicity. Our results revealed that the jasmonic acid (JA) pathway was induced while the brassinosteroid (BR) pathway was suppressed in infected plants. Foliar application of methyl jasmonate (MeJA) or brassinazole (BRZ) resulted in a significant reduction in RBSDV incidence, while epibrassinolide (BL) treatment increased RBSDV infection. Infection studies using coi1-13 and Go mutants demonstrated JA-mediated resistance and BR-mediated susceptibility to RBSDV infection. A mixture of MeJA and BL treatment resulted in a significant reduction in RBSDV infection compared with a single BL treatment. MeJA application efficiently suppressed the expression of BR pathway genes, and this inhibition depended on the JA coreceptor OsCOI1. Collectively, our results reveal that JA-mediated defense can suppress the BR-mediated susceptibility to RBSDV infection. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Fed levels of amino acids are required for the somatotropin-induced increase in muscle protein synthesis.

Science.gov (United States)

Wilson, Fiona A; Suryawan, Agus; Orellana, Renán A; Nguyen, Hanh V; Jeyapalan, Asumthia S; Gazzaneo, Maria C; Davis, Teresa A

2008-10-01

Chronic somatotropin (pST) treatment in pigs increases muscle protein synthesis and circulating insulin, a known promoter of protein synthesis. Previously, we showed that the pST-mediated rise in insulin could not account for the pST-induced increase in muscle protein synthesis when amino acids were maintained at fasting levels. This study aimed to determine whether the pST-induced increase in insulin promotes skeletal muscle protein synthesis when amino acids are provided at fed levels and whether the response is associated with enhanced translation initiation factor activation. Growing pigs were treated with pST (0 or 180 microg x kg(-1) x day(-1)) for 7 days, and then pancreatic-glucose-amino acid clamps were performed. Amino acids were raised to fed levels in the presence of either fasted or fed insulin concentrations; glucose was maintained at fasting throughout. Muscle protein synthesis was increased by pST treatment and by amino acids (with or without insulin) (P<0.001). In pST-treated pigs, fed, but not fasting, amino acid concentrations further increased muscle protein synthesis rates irrespective of insulin level (P<0.02). Fed amino acids, with or without raised insulin concentrations, increased the phosphorylation of S6 kinase (S6K1) and eukaryotic initiation factor (eIF) 4E-binding protein 1 (4EBP1), decreased inactive 4EBP1.eIF4E complex association, and increased active eIF4E.eIF4G complex formation (P<0.02). pST treatment did not alter translation initiation factor activation. We conclude that the pST-induced stimulation of muscle protein synthesis requires fed amino acid levels, but not fed insulin levels. However, under the current conditions, the response to amino acids is not mediated by the activation of translation initiation factors that regulate mRNA binding to the ribosomal complex.

Valproic acid potentiates curcumin-mediated neuroprotection in Lipopolysaccharide induced rats

Directory of Open Access Journals (Sweden)

Amira eZaky

2014-10-01

Full Text Available The etiology of neuroinflammation is complex and comprises multifactorial, involving both genetic and environmental factors during which diverse genetic and epigenetic modulations are implicated. Curcumin (Cur, and valproic acid (VPA, histone deacetylase 1 inhibitor, have neuroprotective effects. The present study was designed with an aim to investigate the ability of co-treatment of both compounds (Cur or VPA (200mg/kg for four weeks to augment neuroprotection and enhance brain recovery from intra-peritoneal (IP injection of (250 µg/kg lipopolysaccharide (LPS-stimulated neuroinflammatory condition on rat brain cortex. Cortex activation and the effects of combined treatment and production of proinflammatory mediators, COX-2, APE1 and nitric oxide/iNOS were investigated. Neuroinflammation development was assessed by histological analyses and by investigating associated indices (BACE1, APP, PSEN-1 and PSEN-2. Furthermore we measured the expression profile of let-7 miRNAs members a, b, c, e and f in all groups, a highly abundant regulator of gene expression in the CNS. Protein and mRNA levels of neuroinflammation markers COX-2, BACE1, APP and iNOS were also attenuated by combined therapy. On the other hand, assessment of the indicated five let-7 members, showed distinct expression profile pattern in the different groups. Let-7 a, b and c disappeared in the induced group, an effect that was partially suppressed by co-addition of either Cur or VPA. These data suggest that the combined treatment induced significantly the expression of the five members when compared to rats treated with Cur or VPA only as well as to self-recovery group, which indicates a possible benefit from the synergistic effect of Cur-VPA combination as therapeutic agents for neuroinflammation and its associated disorders. The mechanism elucidated here highlights the particular drug-induced expression profile of let-7 family as new targets for future pharmacological development.

Albumin-bound fatty acids but not albumin itself alter redox balance in tubular epithelial cells and induce a peroxide-mediated redox-sensitive apoptosis

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Ruggiero, Christine; Elks, Carrie M.; Kruger, Claudia; Cleland, Ellen; Addison, Kaity; Noland, Robert C.

2014-01-01

Albuminuria is associated with metabolic syndrome and diabetes. It correlates with the progression of chronic kidney disease, particularly with tubular atrophy. The fatty acid load on albumin significantly increases in obesity, presenting a proinflammatory environment to the proximal tubules. However, little is known about changes in the redox milieu during fatty acid overload and how redox-sensitive mechanisms mediate cell death. Here, we show that albumin with fatty acid impurities or conjugated with palmitate but not albumin itself compromised mitochondrial and cell viability, membrane potential and respiration. Fatty acid overload led to a redox imbalance which deactivated the antioxidant protein peroxiredoxin 2 and caused a peroxide-mediated apoptosis through the redox-sensitive pJNK/caspase-3 pathway. Transfection of tubular cells with peroxiredoxin 2 was protective and mitigated apoptosis. Mitochondrial fatty acid entry and ceramide synthesis modulators suggested that mitochondrial β oxidation but not ceramide synthesis may modulate lipotoxic effects on tubular cell survival. These results suggest that albumin overloaded with fatty acids but not albumin itself changes the redox environment in the tubules, inducing a peroxide-mediated redox-sensitive apoptosis. Thus, mitigating circulating fatty acid levels may be an important factor in both preserving redox balance and preventing tubular cell damage in proteinuric diseases. PMID:24500687

Maslinic acid ameliorates NMDA receptor blockade-induced schizophrenia-like behaviors in mice.

Science.gov (United States)

Jeon, Se Jin; Kim, Eunji; Lee, Jin Su; Oh, Hee Kyong; Zhang, Jiabao; Kwon, Yubeen; Jang, Dae Sik; Ryu, Jong Hoon

2017-11-01

Schizophrenia is a chronic psychotic disorder characterized by positive, negative, and cognitive symptoms. Primary treatments for schizophrenia relieve the positive symptoms but are less effective against the negative and cognitive symptoms. In the present study, we investigated whether maslinic acid, isolated from Syzygium aromaticum (clove), can ameliorate schizophrenia-like behaviors in mice induced by MK-801, an N-methyl-d-aspartate (NMDA) receptor antagonist. After maslinic acid treatment in the MK-801 model, we examined the behavioral alteration and signaling pathways in the prefrontal cortex. Mice were treated with maslinic acid (30 mg/kg), and their behaviors were evaluated through an array of behavioral tests. The effects of maslinic acid were also examined in the signaling pathways in the prefrontal cortex. A single administration of maslinic acid blocked the MK-801-induced hyperlocomotion and reversed the MK-801-induced sensorimotor gating deficit in the acoustic startle response test. In the social novelty preference test, maslinic acid ameliorated the social behavior deficits induced by MK-801. The MK-801-induced attention and recognition memory impairments were also alleviated by a single administration of maslinic acid. Furthermore, maslinic acid normalized the phosphorylation levels of Akt-GSK-3β and ERK-CREB in the prefrontal cortex. Overall, maslinic acid ameliorated the schizophrenia-like symptoms induced by MK-801, and these effects may be partly mediated through Akt-GSK-3β and ERK-CREB activation. These findings suggest that maslinic acid could be a candidate for the treatment of several symptoms of schizophrenia, including positive symptoms, sensorimotor gating disruption, social interaction deficits, and cognitive impairments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Priming by Hexanoic acid induce activation of mevalonic and linolenic pathways and promotes the emission of plant volatiles.

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Eugenio eLlorens

2016-04-01

Full Text Available Hexanoic acid is a short natural monocarboxylic acid present in some fruits and plants. Previous studies reported that soil drench application of this acid induces effective resistance in tomato plants against Botrytis cinerea and Pseudomonas syringae and in citrus against Alternaria alternata and Xanthomonas citri. In this work, we performed an in deep study of the metabolic changes produced in citrus by the application of hexanoic acid in response to the challenge pathogen Alternaria alternata, focusing on the response of the plant. Moreover, we used 13C labeled hexanoic to analyze its behavior inside the plants. Finally, we studied the volatile emission of the treated plants after the challenge inoculation. Drench application of 13C labeled hexanoic demonstrated that this molecule stays in the roots and is not mobilized to the leaves, suggesting long distance induction of resistance. Moreover, the study of the metabolic profile showed an alteration of more than two hundred molecules differentially induced by the application of the compound and the inoculation with the fungus. Bioinformatics analysis of data showed that most of these altered molecules could be related with the mevalonic and linolenic pathways suggesting the implication of these pathways in the induced resistance mediated by hexanoic acid. Finally, the application of this compound showed an enhancement of the emission of 17 volatile metabolites. Taken together, this study indicates that after the application of hexanoic acid this compound remains in the roots, provoking molecular changes that may trigger the defensive response in the rest of the plant mediated by changes in the mevalonic and linolenic pathways and enhancing the emission of volatile compounds, suggesting for the first time the implication of mevalonic pathway in response to hexanoic application.

Nitric oxide-mediated bystander signal transduction induced by heavy-ion microbeam irradiation

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Tomita, Masanori; Matsumoto, Hideki; Funayama, Tomoo; Yokota, Yuichiro; Otsuka, Kensuke; Maeda, Munetoshi; Kobayashi, Yasuhiko

2015-07-01

In general, a radiation-induced bystander response is known to be a cellular response induced in non-irradiated cells after receiving bystander signaling factors released from directly irradiated cells within a cell population. Bystander responses induced by high-linear energy transfer (LET) heavy ions at low fluence are an important health problem for astronauts in space. Bystander responses are mediated via physical cell-cell contact, such as gap-junction intercellular communication (GJIC) and/or diffusive factors released into the medium in cell culture conditions. Nitric oxide (NO) is a well-known major initiator/mediator of intercellular signaling within culture medium during bystander responses. In this study, we investigated the NO-mediated bystander signal transduction induced by high-LET argon (Ar)-ion microbeam irradiation of normal human fibroblasts. Foci formation by DNA double-strand break repair proteins was induced in non-irradiated cells, which were co-cultured with those irradiated by high-LET Ar-ion microbeams in the same culture plate. Foci formation was suppressed significantly by pretreatment with an NO scavenger. Furthermore, NO-mediated reproductive cell death was also induced in bystander cells. Phosphorylation of NF-κB and Akt were induced during NO-mediated bystander signaling in the irradiated and bystander cells. However, the activation of these proteins depended on the incubation time after irradiation. The accumulation of cyclooxygenase-2 (COX-2), a downstream target of NO and NF-κB, was observed in the bystander cells 6 h after irradiation but not in the directly irradiated cells. Our findings suggest that Akt- and NF-κB-dependent signaling pathways involving COX-2 play important roles in NO-mediated high-LET heavy-ion-induced bystander responses. In addition, COX-2 may be used as a molecular marker of high-LET heavy-ion-induced bystander cells to distinguish them from directly irradiated cells, although this may depend on the time

Asiatic acid attenuates methamphetamine-induced neuroinflammation and neurotoxicity through blocking of NF-kB/STAT3/ERK and mitochondria-mediated apoptosis pathway

OpenAIRE

Park, Ji-Hyun; Seo, Young Ho; Jang, Jung-Hee; Jeong, Chul-Ho; Lee, Sooyeun; Park, Byoungduck

2017-01-01

Background Methamphetamine (METH) is a commonly abused drug that may result in neurotoxic effects. Recent studies have suggested that involvement of neuroinflammatory processes in brain dysfunction is induced by misuse of this drug. However, the mechanism underlying METH-induced inflammation and neurotoxicity in neurons is still unclear. In this study, we investigated whether asiatic acid (AA) effected METH-mediated neuroinflammation and neurotoxicity in dopaminergic neuronal cells. And we fu...

Inflammatory mediator profiles in tears accompanying keratoconjunctival responses induced by nasal allergy.

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Pelikan, Zdenek

2013-07-01

The allergic reaction taking place in the nasal mucosa can induce a secondary ocular (keratoconjunctival) response of an immediate (SIOR), late (SLOR) or delayed (SDYOR) type in some patients with keratoconjunctivitis (KC). To investigate the concentration changes of histamine, tryptase, eosinophil-derived neurotoxin (EDN), eosinophil cationic protein (ECP), eosinophilic peroxidase (EPO), leucotrienes (LTB₄, LTC₄, LTE₄), prostaglandins (PGD₂, PGE₂ and PGF₂α), thromboxane B₂ (TXB₂), myeloperoxidase (MPO), interferon-γ (IFN-γ) and interleukins (IL-2, IL-4 and IL-5) in tears during the SIOR, SLOR and SDYOR. 19 SIORs (ptears. The ocular response types were associated with significant changes (ptears as follows: (1) SIORs: histamine, tryptase, ECP, LTC₄, PGD₂, PGF₂α, IL-4 and IL-5; (2) SLORs: histamine, ECP, EDN, LTB₄, LTC₄, PGE₂, MPO, IL-4 and IL-5; (3) SDYORs: LTB4, TXB₂, MPO, IFN-γ and IL-2. No significant changes of these factors were measured in tears during the 57 PBS controls (p>0.1). These results demonstrate a causal involvement of nasal allergy in some KC patients, inducing a secondary keratoconjunctival response of an immediate (SIOR), late (SLOR) or delayed (SDYOR) type, associated with different inflammatory mediator profiles in the tears, suggesting participation of different hypersensitivity mechanisms. These results also emphasise the diagnostic value of nasal challenge with allergen combined with monitoring of ocular response in KC patients, responding insufficiently to the usual ophthalmologic therapy.

Jasmonic Acid Enhances Al-Induced Root Growth Inhibition.

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Yang, Zhong-Bao; He, Chunmei; Ma, Yanqi; Herde, Marco; Ding, Zhaojun

2017-02-01

Phytohormones such as ethylene and auxin are involved in the regulation of the aluminum (Al)-induced root growth inhibition. Although jasmonate (JA) has been reported to play a crucial role in the regulation of root growth and development in response to environmental stresses through interplay with ethylene and auxin, its role in the regulation of root growth response to Al stress is not yet known. In an attempt to elucidate the role of JA, we found that exogenous application of JA enhanced the Al-induced root growth inhibition. Furthermore, phenotype analysis with mutants defective in either JA biosynthesis or signaling suggests that JA is involved in the regulation of Al-induced root growth inhibition. The expression of the JA receptor CORONATINE INSENSITIVE1 (COI1) and the key JA signaling regulator MYC2 was up-regulated in response to Al stress in the root tips. This process together with COI1-mediated Al-induced root growth inhibition under Al stress was controlled by ethylene but not auxin. Transcriptomic analysis revealed that many responsive genes under Al stress were regulated by JA signaling. The differential responsive of microtubule organization-related genes between the wild-type and coi1-2 mutant is consistent with the changed depolymerization of cortical microtubules in coi1 under Al stress. In addition, ALMT-mediated malate exudation and thus Al exclusion from roots in response to Al stress was also regulated by COI1-mediated JA signaling. Together, this study suggests that root growth inhibition is regulated by COI1-mediated JA signaling independent from auxin signaling and provides novel insights into the phytohormone-mediated root growth inhibition in response to Al stress. © 2017 American Society of Plant Biologists. All Rights Reserved.

Preventive effects of omega-3 and omega-6 Fatty acids on peroxide mediated oxidative stress responses in primary human trabecular meshwork cells.

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Theofilos Tourtas

Full Text Available Pathologic processes in glaucoma include increased apoptosis, accumulation of extracellular material in the trabecular meshwork and optic nerve, condensations of the cytoskeleton and precocious cellular senescence. Oxidative stress was shown to generate these alterations in primary ocular cells. Fatty acids omega-3 and -6 are alleged to constitute a prophylaxis against these deleterious effects. Here, we tested actual preventive effects omega-3 and -6 against peroxide induced stress responses in primary human trabecular meshwork cells. Changes of mitochondrial activity, proliferation, heat shock proteins, extracellular matrix components, and inflammatory markers were evaluated. Alterations of the cytoskeleton were evaluated by phalloidin labeling. Here we report a repressive effect of omega-6 on metabolic activity and proliferation, which was not detected for omega-3. Both agents were able to prevent the anti-proliferative effect of H₂O₂, but only omega-3 prevented metabolic repression. Expression of heat shock protein 27 was unaltered by both fatty acids, whereas heat shock protein 90 was significantly induced by both. Omega-6 increased fibronectin and connective tissue growth factor synthesis, as well as the amount of secreted fibronectin. Omega-3, instead, induced plasminogen activator inhibitor 1 synthesis. H₂O₂ further increased fibronectin production in omega-6 supplemented cells, which was not the case in omega-3 treated cells. H₂O₂ stimulation of plasminogen activator inhibitor 1 and connective tissue growth factor was repressed by both fatty acids. Both fatty acids appeared to abolish H₂O₂ mediated stimulation of nuclear factor κB and IL-6, but not IL-1α and IL-8. H₂O₂ induced formation of cross-linked actin networks and stress fibers, which was reduced by preemptive application of omega-3. Omega-6, in contrast, had no protective effect on that, and even seemed to promote condensation. Based on the observed side

Sensing and adaptation to low pH mediated by inducible amino acid decarboxylases in Salmonella.

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Viala, Julie P M; Méresse, Stéphane; Pocachard, Bérengère; Guilhon, Aude-Agnès; Aussel, Laurent; Barras, Frédéric

2011-01-01

During the course of infection, Salmonella enterica serovar Typhimurium must successively survive the harsh acid stress of the stomach and multiply into a mild acidic compartment within macrophages. Inducible amino acid decarboxylases are known to promote adaptation to acidic environments. Three low pH inducible amino acid decarboxylases were annotated in the genome of S. Typhimurium, AdiA, CadA and SpeF, which are specific for arginine, lysine and ornithine, respectively. In this study, we characterized and compared the contributions of those enzymes in response to acidic challenges. Individual mutants as well as a strain deleted for the three genes were tested for their ability (i) to survive an extreme acid shock, (ii) to grow at mild acidic pH and (iii) to infect the mouse animal model. We showed that the lysine decarboxylase CadA had the broadest range of activity since it both had the capacity to promote survival at pH 2.3 and growth at pH 4.5. The arginine decarboxylase AdiA was the most performant in protecting S. Typhimurium from a shock at pH 2.3 and the ornithine decarboxylase SpeF conferred the best growth advantage under anaerobiosis conditions at pH 4.5. We developed a GFP-based gene reporter to monitor the pH of the environment as perceived by S. Typhimurium. Results showed that activities of the lysine and ornithine decarboxylases at mild acidic pH did modify the local surrounding of S. Typhimurium both in culture medium and in macrophages. Finally, we tested the contribution of decarboxylases to virulence and found that these enzymes were dispensable for S. Typhimurium virulence during systemic infection. In the light of this result, we examined the genomes of Salmonella spp. normally responsible of systemic infection and observed that the genes encoding these enzymes were not well conserved, supporting the idea that these enzymes may be not required during systemic infection.

Sensing and adaptation to low pH mediated by inducible amino acid decarboxylases in Salmonella.

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Julie P M Viala

Full Text Available During the course of infection, Salmonella enterica serovar Typhimurium must successively survive the harsh acid stress of the stomach and multiply into a mild acidic compartment within macrophages. Inducible amino acid decarboxylases are known to promote adaptation to acidic environments. Three low pH inducible amino acid decarboxylases were annotated in the genome of S. Typhimurium, AdiA, CadA and SpeF, which are specific for arginine, lysine and ornithine, respectively. In this study, we characterized and compared the contributions of those enzymes in response to acidic challenges. Individual mutants as well as a strain deleted for the three genes were tested for their ability (i to survive an extreme acid shock, (ii to grow at mild acidic pH and (iii to infect the mouse animal model. We showed that the lysine decarboxylase CadA had the broadest range of activity since it both had the capacity to promote survival at pH 2.3 and growth at pH 4.5. The arginine decarboxylase AdiA was the most performant in protecting S. Typhimurium from a shock at pH 2.3 and the ornithine decarboxylase SpeF conferred the best growth advantage under anaerobiosis conditions at pH 4.5. We developed a GFP-based gene reporter to monitor the pH of the environment as perceived by S. Typhimurium. Results showed that activities of the lysine and ornithine decarboxylases at mild acidic pH did modify the local surrounding of S. Typhimurium both in culture medium and in macrophages. Finally, we tested the contribution of decarboxylases to virulence and found that these enzymes were dispensable for S. Typhimurium virulence during systemic infection. In the light of this result, we examined the genomes of Salmonella spp. normally responsible of systemic infection and observed that the genes encoding these enzymes were not well conserved, supporting the idea that these enzymes may be not required during systemic infection.

Abscisic Acid and Gibberellins Antagonistically Mediate Plant Development and Abiotic Stress Responses

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Kai Shu

2018-03-01

Full Text Available Phytohormones regulate numerous important biological processes in plant development and biotic/abiotic stress response cascades. More than 50 and 100 years have passed since the initial discoveries of the phytohormones abscisic acid (ABA and gibberellins (GA, respectively. Over the past several decades, numerous elegant studies have demonstrated that ABA and GA antagonistically regulate many plant developmental processes, including seed maturation, seed dormancy and germination, root initiation, hypocotyl and stem elongation, and floral transition. Furthermore, as a well-established stress hormone, ABA plays a key role in plant responses to abiotic stresses, such as drought, flooding, salinity and low temperature. Interestingly, recent evidence revealed that GA are also involved in plant response to adverse environmental conditions. Consequently, the complex crosstalk networks between ABA and GA, mediated by diverse key regulators, have been extensively investigated and documented. In this updated mini-review, we summarize the most recent advances in our understanding of the antagonistically regulatory roles of ABA and GA in different stages of plant development and in various plant–environment interactions, focusing on the crosstalk between ABA and GA at the levels of phytohormone metabolism and signal transduction.

Nicotinic acid-induced flushing is mediated by activation of epidermal langerhans cells

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Benyó, Zoltán; Gille, Andreas; Bennett, Clare L.; Clausen, Björn E.; Offermanns, Stefan

2006-01-01

The antidyslipidemic drug nicotinic acid (niacin) has been used for decades. One of the major problems of the therapeutical use of nicotinic acid is a strong cutaneous vasodilation called flushing, which develops in almost every patient taking nicotinic acid. Nicotinic acid-induced flushing has been

Shanxi Aged Vinegar Protects against Alcohol-Induced Liver Injury via Activating Nrf2-Mediated Antioxidant and Inhibiting TLR4-Induced Inflammatory Response

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Ting Xia

2018-06-01

Full Text Available Shanxi aged vinegar (SAV is a typical fermented and antioxidant food, which has various health-promoting effects. This work aimed to explore the effects of SAV on alcohol-induced liver injury. A mice model of alcoholic liver injury was established to illuminate its potential mechanisms. All mice pretreated with SAV and then received an ethanol solution (50% w/v, 4.8 g/kg b.w.. The results showed that SAV ameliorated alcohol-induced histological changes and elevation of liver enzymes. SAV attenuated alcohol-induced oxidative stress by declining levels of hepatic oxidants, and restoring depletion of antioxidant enzyme activities in mice livers. Moreover, SAV alleviated alcohol-induced oxidative damage by activating nuclear factor erythroid-2-related factor 2 (Nrf2-mediated signal pathway. In addition, SAV prevented alcohol-induced inflammation by suppressing lipopolysaccharide (LPS level and activities of pro-inflammatory enzymes, and regulating inflammatory cytokines. SAV inhibited alcohol-induced inflammation through down-regulating the expression of Toll-like receptor 4 (TLR4-mediated inflammatory response. The findings provide crucial evidence for elucidating the hepatoprotective mechanisms of SAV and encourage the future application of SAV as a functional food for liver protection.

Arginine- and Polyamine-Induced Lactic Acid Resistance in Neisseria gonorrhoeae.

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Zheng Gong

Full Text Available Microbe-derived lactic acid protects women from pathogens in their genital tract. The purpose of this study was to determine lactic acid susceptibility of Neisseria gonorrhoeae, and identify potential acid resistance mechanisms present in this pathogen. Tested in vitro, lactic acid killed all 10 gonococcal strains analyzed in a low pH-dependent manner. Full inactivation occurred at pH 4.5. At low pH, lactic acid treatment resulted in the entry of the DNA-binding fluorochrome propidium iodide into the microbial cells, suggesting that hydrogen ions from lactic acid compromise the integrity of the bacterial cell wall/membrane. Most likely, hydrogen ions also inactivate intracellular proteins since arginine rendered significant protection against lactic acid presumably through action of the gonococcal arginine decarboxylase, an enzyme located in the bacterial cytoplasm. Surprisingly, arginine also lessened lactic acid-mediated cell wall/membrane disruption. This effect is probably mediated by agmatine, a triamine product of arginine decarboxylase, since agmatine demonstrated a stronger protective effect on GC than arginine at equal molar concentration. In addition to agmatine, diamines cadaverine and putrescine, which are generated by bacterial vaginosis-associated microbes, also induced significant resistance to lactic acid-mediated GC killing and cell wall/membrane disruption. These findings suggest that the arginine-rich semen protects gonococci through both neutralization-dependent and independent mechanisms, whereas polyamine-induced acid resistance contributes to the increased risk of gonorrhea in women with bacterial vaginosis.

Ebselen abrogates TNFα induced pro‐inflammatory response in glioblastoma

OpenAIRE

Tewari, Richa; Sharma, Vivek; Koul, Nitin; Ghosh, Abhishek; Joseph, Christy; Hossain Sk, Ugir; Sen, Ellora

2008-01-01

We investigated the pro‐inflammatory response mediated by TNFα in glioblastoma and whether treatment with organoselenium Ebselen (2‐phenyl‐1,2‐benzisoselenazol‐3[2H]one) can affect TNFα induced inflammatory response. Exposure to TNFα increased the expression of pro‐inflammatory mediator interleukin IL‐6, IL‐8, monocyte chemoattractant protein‐1 (MCP‐1) and cyclooxygenase (COX‐2). Treatment with Ebselen abrogated TNFα induced increase in pro‐inflammatory mediators. Ebselen not only abrogated T...

Transcriptomic analysis of rice aleurone cells identified a novel abscisic acid response element.

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Watanabe, Kenneth A; Homayouni, Arielle; Gu, Lingkun; Huang, Kuan-Ying; Ho, Tuan-Hua David; Shen, Qingxi J

2017-09-01

Seeds serve as a great model to study plant responses to drought stress, which is largely mediated by abscisic acid (ABA). The ABA responsive element (ABRE) is a key cis-regulatory element in ABA signalling. However, its consensus sequence (ACGTG(G/T)C) is present in the promoters of only about 40% of ABA-induced genes in rice aleurone cells, suggesting other ABREs may exist. To identify novel ABREs, RNA sequencing was performed on aleurone cells of rice seeds treated with 20 μM ABA. Gibbs sampling was used to identify enriched elements, and particle bombardment-mediated transient expression studies were performed to verify the function. Gene ontology analysis was performed to predict the roles of genes containing the novel ABREs. This study revealed 2443 ABA-inducible genes and a novel ABRE, designated as ABREN, which was experimentally verified to mediate ABA signalling in rice aleurone cells. Many of the ABREN-containing genes are predicted to be involved in stress responses and transcription. Analysis of other species suggests that the ABREN may be monocot specific. This study also revealed interesting expression patterns of genes involved in ABA metabolism and signalling. Collectively, this study advanced our understanding of diverse cis-regulatory sequences and the transcriptomes underlying ABA responses in rice aleurone cells. © 2017 John Wiley & Sons Ltd.

Treating cutaneous squamous cell carcinoma using 5-aminolevulinic acid polylactic-co-glycolic acid nanoparticle-mediated photodynamic therapy in a mouse model

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Wang X

2015-01-01

Full Text Available Xiaojie Wang,1,2,* Lei Shi,2,* Qingfeng Tu,2 Hongwei Wang,3 Haiyan Zhang,2 Peiru Wang,2 Linglin Zhang,2 Zheng Huang,4 Feng Zhao,5 Hansen Luan,5 Xiuli Wang2 1Shanghai Skin Diseases Clinical College of Anhui Medical University, 2Shanghai Skin Disease Hospital, 3Huadong Hospital, Fudan University, Shanghai, 4MOE Key Laboratory of OptoElectronic Science and Technology for Medicine, Fujian Normal University, Fuzhou, 5National Pharmaceutical Engineering Research Center, China State Institute of Pharmaceutical Industry, Shanghai, People’s Republic of China *These authors contributed equally to this study Background: Squamous cell carcinoma (SCC is a common skin cancer, and its treatment is still difficult. The aim of this study was to evaluate the effectiveness of nanoparticle (NP-assisted 5-aminolevulinic acid (ALA delivery for topical photodynamic therapy (PDT of cutaneous SCC.Materials and methods: Ultraviolet-induced cutaneous SCCs were established in hairless mice. ALA-loaded polylactic-co-glycolic acid (PLGA NPs were prepared and characterized. The kinetics of ALA PLGA NP-induced protoporphyrin IX fluorescence in SCCs, therapeutic efficacy of ALA NP-mediated PDT, and immune responses were examined.Results: PLGA NPs enhanced protoporphyrin IX production in SCC. ALA PLGA NP-mediated topical PDT was more effective than free ALA of the same concentration in treating cutaneous SCC.Conclusion: PLGA NPs provide a promising strategy for delivering ALA in topical PDT of cutaneous SCC. Keywords: 5-aminolevulinic acid (ALA, polylactic-co-glycolic acid (PLGA, nanoparticles (NPs, cutaneous squamous cell carcinoma (SCC, photodynamic therapy (PDT, microneedling

PTH1 receptor is involved in mediating cellular response to long-chain polyunsaturated fatty acids.

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Jose Candelario

Full Text Available The molecular pathways by which long chain polyunsaturated fatty acids (LCPUFA influence skeletal health remain elusive. Both LCPUFA and parathyroid hormone type 1 receptor (PTH1R are known to be involved in bone metabolism while any direct link between the two is yet to be established. Here we report that LCPUFA are capable of direct, PTH1R dependent activation of extracellular ligand-regulated kinases (ERK. From a wide range of fatty acids studied, varying in chain length, saturation, and position of double bonds, eicosapentaenoic (EPA and docosahexaenoic fatty acids (DHA caused the highest ERK phosphorylation. Moreover, EPA potentiated the effect of parathyroid hormone (PTH(1-34 in a superagonistic manner. EPA or DHA dependent ERK phosphorylation was inhibited by the PTH1R antagonist and by knockdown of PTH1R. Inhibition of PTH1R downstream signaling molecules, protein kinases A (PKA and C (PKC, reduced EPA and DHA dependent ERK phosphorylation indicating that fatty acids predominantly activate G-protein pathway and not the β-arrestin pathway. Using picosecond time-resolved fluorescence microscopy and a genetically engineered PTH1R sensor (PTH-CC, we detected conformational responses to EPA similar to those caused by PTH(1-34. PTH1R antagonist blocked the EPA induced conformational response of the PTH-CC. Competitive binding studies using fluorescence anisotropy technique showed that EPA and DHA competitively bind to and alter the affinity of PTH1 receptor to PTH(1-34 leading to a superagonistic response. Finally, we showed that EPA stimulates protein kinase B (Akt phosphorylation in a PTH1R-dependent manner and affects the osteoblast survival pathway, by inhibiting glucocorticoid-induced cell death. Our findings demonstrate for the first time that LCPUFAs, EPA and DHA, can activate PTH1R receptor at nanomolar concentrations and consequently provide a putative molecular mechanism for the action of fatty acids in bone.

2-Chlorohexadecanoic acid induces ER stress and mitochondrial dysfunction in brain microvascular endothelial cells

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Eva Bernhart

2018-05-01

Full Text Available Peripheral leukocytes induce blood-brain barrier (BBB dysfunction through the release of cytotoxic mediators. These include hypochlorous acid (HOCl that is formed via the myeloperoxidase-H2O2-chloride system of activated phagocytes. HOCl targets the endogenous pool of ether phospholipids (plasmalogens generating chlorinated inflammatory mediators like e.g. 2-chlorohexadecanal and its conversion product 2-chlorohexadecanoic acid (2-ClHA. In the cerebrovasculature these compounds inflict damage to brain microvascular endothelial cells (BMVEC that form the morphological basis of the BBB. To follow subcellular trafficking of 2-ClHA we synthesized a ‘clickable’ alkyne derivative (2-ClHyA that phenocopied the biological activity of the parent compound. Confocal and superresolution structured illumination microscopy revealed accumulation of 2-ClHyA in the endoplasmic reticulum (ER and mitochondria of human BMVEC (hCMEC/D3 cell line. 2-ClHA and its alkyne analogue interfered with protein palmitoylation, induced ER-stress markers, reduced the ER ATP content, and activated transcription and secretion of interleukin (IL−6 as well as IL-8. 2-ClHA disrupted the mitochondrial membrane potential and induced procaspase-3 and PARP cleavage. The protein kinase R-like ER kinase (PERK inhibitor GSK2606414 suppressed 2-ClHA-mediated activating transcription factor 4 synthesis and IL-6/8 secretion, but showed no effect on endothelial barrier dysfunction and cleavage of procaspase-3. Our data indicate that 2-ClHA induces potent lipotoxic responses in brain endothelial cells and could have implications in inflammation-induced BBB dysfunction.

Purple sweet potato color attenuates domoic acid-induced cognitive deficits by promoting estrogen receptor-α-mediated mitochondrial biogenesis signaling in mice.

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Lu, Jun; Wu, Dong-Mei; Zheng, Yuan-Lin; Hu, Bin; Cheng, Wei; Zhang, Zi-Feng

2012-02-01

Recent findings suggest that endoplasmic reticulum stress may be involved in the pathogenesis of domoic acid-induced neurodegeneration. Purple sweet potato color, a class of naturally occurring anthocyanins, has beneficial health and biological effects. Recent studies have also shown that anthocyanins have estrogenic activity and can enhance estrogen receptor-α expression. In this study, we evaluated the effect of purple sweet potato color on cognitive deficits induced by hippocampal mitochondrial dysfunction in domoic acid-treated mice and explored the potential mechanisms underlying this effect. Our results showed that the oral administration of purple sweet potato color to domoic acid-treated mice significantly improved their behavioral performance in a step-through passive avoidance task and a Morris water maze task. These improvements were mediated, at least in part, by a stimulation of estrogen receptor-α-mediated mitochondrial biogenesis signaling and by decreases in the expression of p47phox and gp91phox. Decreases in reactive oxygen species and protein carbonylation were also observed, along with a blockade of the endoplasmic reticulum stress pathway. Furthermore, purple sweet potato color significantly suppressed endoplasmic reticulum stress-induced apoptosis, which prevented neuron loss and restored the expression of memory-related proteins. However, knockdown of estrogen receptor-α using short hairpin RNA only partially blocked the neuroprotective effects of purple sweet potato color in the hippocampus of mice cotreated with purple sweet potato color and domoic acid, indicating that purple sweet potato color acts through multiple pathways. These results suggest that purple sweet potato color could be a possible candidate for the prevention and treatment of cognitive deficits in excitotoxic and other brain disorders. Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.

Salicylic acid improves salinity tolerance in Arabidopsis by restoring membrane potential and preventing salt-induced K+ loss via a GORK channel

OpenAIRE

Jayakannan, Maheswari; Bose, Jayakumar; Babourina, Olga; Rengel, Zed; Shabala, Sergey

2013-01-01

Despite numerous reports implicating salicylic acid (SA) in plant salinity responses, the specific ionic mechanisms of SA-mediated adaptation to salt stress remain elusive. To address this issue, a non-invasive microelectrode ion flux estimation technique was used to study kinetics of NaCl-induced net ion fluxes in Arabidopsis thaliana in response to various SA concentrations and incubation times. NaCl-induced K+ efflux and H+ influx from the mature root zone were both significantly decreased...

Anti-Inflammatory Effects of Benfotiamine are Mediated Through the Regulation of Arachidonic Acid Pathway in Macrophages

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Shoeb, Mohammad; Ramana, Kota V

2011-01-01

Benfotiamine, a lipid-soluble analogue of vitamin B1, is a potent anti-oxidant that is used as a food supplement for the treatment of diabetic complications. Our recent study indicates a novel role of benfotiamine in the prevention of bacterial endotoxin, lipopolysaccharide (LPS)-induced cytotoxicity and inflammatory response in murine macrophages. Nevertheless, it remains unclear how benfotiamine mediates anti-inflammatory effects. In this study, we investigated the anti-inflammatory role of benfotiamine in regulating the arachidonic acid (AA) pathway generated inflammatory lipid mediators in RAW 264.7 macrophages. Benfotiamine prevented the LPS-induced activation of cPLA2 and release of AA metabolites such as leukotrienes (LTB4), prostaglandin E2 (PGE2), thromboxanes 2 (TXB2) and prostacyclin (PGI2) in macrophages. Further, LPS-induced expressions of AA metabolizing enzymes such as COX-2, LOX-5, TXB synthase and PGI2 synthase were significantly blocked by benfotiamine. Furthermore, benfotiamine prevented the LPS-induced phosphorylation of ERK1/2 and expression of transcription factors NF-kB, and Egr-1. Benfotiamine also prevented the LPS-induced oxidative stress and protein-HNE adducts formation. Most importantly, as compared to specific COX-2 and LOX-5 inhibitors, benfotiamine significantly prevented the LPS-induced macrophage death and monocytes adhesion to endothelial cells. Thus, our studies indicate that the dual regulation of COX and LOX pathways in AA metabolism could be a novel mechanism by which benfotiamine exhibits its potential anti-inflammatory response. PMID:22067901

Salicylic acid induces vanillin synthesis through the phospholipid signaling pathway in Capsicum chinense cell cultures.

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Rodas-Junco, Beatriz A; Cab-Guillén, Yahaira; Muñoz-Sánchez, J Armando; Vázquez-Flota, Felipe; Monforte-González, Miriam; Hernández-Sotomayor, S M Teresa

2013-10-01

Signal transduction via phospholipids is mediated by phospholipases such as phospholipase C (PLC) and D (PLD), which catalyze hydrolysis of plasma membrane structural phospholipids. Phospholipid signaling is also involved in plant responses to phytohormones such as salicylic acid (SA). The relationships between phospholipid signaling, SA, and secondary metabolism are not fully understood. Using a Capsicum chinense cell suspension as a model, we evaluated whether phospholipid signaling modulates SA-induced vanillin production through the activation of phenylalanine ammonia lyase (PAL), a key enzyme in the biosynthetic pathway. Salicylic acid was found to elicit PAL activity and consequently vanillin production, which was diminished or reversed upon exposure to the phosphoinositide-phospholipase C (PI-PLC) signaling inhibitors neomycin and U73122. Exposure to the phosphatidic acid inhibitor 1-butanol altered PLD activity and prevented SA-induced vanillin production. Our results suggest that PLC and PLD-generated secondary messengers may be modulating SA-induced vanillin production through the activation of key biosynthetic pathway enzymes.

Adenovirus Vector-Derived VA-RNA-Mediated Innate Immune Responses

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Hiroyuki Mizuguchi

2011-07-01

Full Text Available The major limitation of the clinical use of replication-incompetent adenovirus (Ad vectors is the interference by innate immune responses, including induction of inflammatory cytokines and interferons (IFN, following in vivo application of Ad vectors. Ad vector-induced production of inflammatory cytokines and IFNs also results in severe organ damage and efficient induction of acquired immune responses against Ad proteins and transgene products. Ad vector-induced innate immune responses are triggered by the recognition of Ad components by pattern recognition receptors (PRRs. In order to reduce the side effects by Ad vector-induced innate immune responses and to develop safer Ad vectors, it is crucial to clarify which PRRs and which Ad components are involved in Ad vector-induced innate immune responses. Our group previously demonstrated that myeloid differentiating factor 88 (MyD88 and toll-like receptor 9 (TLR9 play crucial roles in the Ad vector-induced inflammatory cytokine production in mouse bone marrow-derived dendritic cells. Furthermore, our group recently found that virus associated-RNAs (VA-RNAs, which are about 160 nucleotide-long non-coding small RNAs encoded in the Ad genome, are involved in IFN production through the IFN-β promoter stimulator-1 (IPS-1-mediated signaling pathway following Ad vector transduction. The aim of this review is to highlight the Ad vector-induced innate immune responses following transduction, especially VA-RNA-mediated innate immune responses. Our findings on the mechanism of Ad vector-induced innate immune responses should make an important contribution to the development of safer Ad vectors, such as an Ad vector lacking expression of VA-RNAs.

A systems approach for discovering linoleic acid derivatives that potentially mediate pain and itch

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Ramsden, Christopher E.; Domenichiello, Anthony F.; Yuan, Zhi-Xin; Sapio, Matthew R.; Keyes, Gregory S.; Mishra, Santosh K.; Gross, Jacklyn R.; Majchrzak-Hong, Sharon; Zamora, Daisy; Horowitz, Mark S.; Davis, John M.; Sorokin, Alexander V.; Dey, Amit; LaPaglia, Danielle M.; Wheeler, Joshua J.; Vasko, Michael R.; Mehta, Nehal N.; Mannes, Andrew J.; Iadarola, Michael J.

2018-01-01

Chronic pain and itch are common hypersensitivity syndromes that are affected by endogenous mediators. We applied a systems-based, translational approach to predict, discover, and characterize mediators of pain and itch that are regulated by diet and inflammation. Profiling of tissue-specific precursor abundance and biosynthetic gene expression predicted that inflamed skin would be abundant in four previously unknown 11-hydroxy-epoxy-or 11-keto-epoxy-octadecenoate linoleic acid derivatives and four previously identified 9- or 13-hydroxy-epoxy- or 9- or 13-keto-epoxy-octadecenoate linoleic acid derivatives. All of these mediators were confirmed to be abundant in rat and human skin by mass spectrometry. However, only the two 11-hydroxy-epoxy-octadecenoates sensitized rat dorsal root ganglion neurons to release more calcitonin gene–related peptide (CGRP), which is involved in pain transmission, in response to low pH (which mimics an inflammatory state) or capsaicin (which activates ion channels involved in nociception). The two 11-hydroxy-epoxy-octadecenoates share a 3-hydroxy-Z-pentenyl-E-epoxide moiety, thus suggesting that this substructure could mediate nociceptor sensitization. In rats, intradermal hind paw injection of 11-hydroxy-12,13-trans-epoxy-(9Z)-octadecenoate elicited C-fiber–mediated sensitivity to thermal pain. In a randomized trial testing adjunctive strategies to manage refractory chronic headaches, reducing the dietary intake of linoleic acid was associated with decreases in plasma 11-hydroxy-12,13-trans-epoxy-(9Z)-octadecenoate, which correlated with clinical pain reduction. Human psoriatic skin had 30-fold higher 9-keto-12,13-trans-epoxy-(10E)-octadecenoate compared to control skin, and intradermal injection of this compound induced itch-related scratching behavior in mice. Collectively, these findings define a family of endogenous mediators with potential roles in pain and itch. PMID:28831021

Ursolic acid-mediated changes in glycolytic pathway promote cytotoxic autophagy and apoptosis in phenotypically different breast cancer cells.

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Lewinska, Anna; Adamczyk-Grochala, Jagoda; Kwasniewicz, Ewa; Deregowska, Anna; Wnuk, Maciej

2017-06-01

Plant-derived pentacyclic triterpenotids with multiple biological activities are considered as promising candidates for cancer therapy and prevention. However, their mechanisms of action are not fully understood. In the present study, we have analyzed the effects of low dose treatment (5-20 µM) of ursolic acid (UA) and betulinic acid (BA) on breast cancer cells of different receptor status, namely MCF-7 (ER + , PR +/- , HER2 - ), MDA-MB-231 (ER - , PR - , HER2 - ) and SK-BR-3 (ER - , PR - , HER2 + ). UA-mediated response was more potent than BA-mediated response. Triterpenotids (5-10 µM) caused G0/G1 cell cycle arrest, an increase in p21 levels and SA-beta-galactosidase staining that was accompanied by oxidative stress and DNA damage. UA (20 µM) also diminished AKT signaling that affected glycolysis as judged by decreased levels of HK2, PKM2, ATP and lactate. UA-induced energy stress activated AMPK that resulted in cytotoxic autophagy and apoptosis. UA-mediated elevation in nitric oxide levels and ATM activation may also account for AMPK activation-mediated cytotoxic response. Moreover, UA-promoted apoptosis was associated with decreased pERK1/2 signals and the depolarization of mitochondrial membrane potential. Taken together, we have shown for the first time that UA at low micromolar range may promote its anticancer action by targeting glycolysis in phenotypically distinct breast cancer cells.

Uric Acid, Hyperuricemia and Vascular Diseases

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Jin, Ming; Yang, Fan; Yang, Irene; Yin, Ying; Luo, Jin Jun; Wang, Hong; Yang, Xiao-Feng

2011-01-01

Uric acid is the product of purine metabolism. It is known that hyperuricemia, defined as high levels of blood uric acid, is the major etiological factor of gout. A number of epidemiological reports have increasingly linked hyperuricemia with cardiovascular and neurological diseases. Studies highlighting the pathogenic mechanisms of uric acid point to an inflammatory response as the primary mechanism for inducing gout and possibly contributing to uric acid's vascular effects. Monosodium urate (MSU) crystals induce an inflammatory reaction, which are recognized by Toll-like receptors (TLRs). These TLRs then activate NALP3 inflammasome. MSU also triggers neutrophil activation and further produces immune mediators, which lead to a proinflammatory response. In addition, soluble uric acid can also mediate the generation of free radicals and function as a pro-oxidant. This review summarizes the epidemiological studies of hyperuricemia and cardiovascular disease, takes a brief look at hyperuricemia and its role in neurological diseases, and highlights the studies of the advanced pathological mechanisms of uric acid and inflammation. PMID:22201767

Duox2-induced innate immune responses in the respiratory epithelium and intranasal delivery of Duox2 DNA using polymer that mediates immunization.

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Jeon, Yung Jin; Kim, Hyun Jik

2018-05-01

Respiratory mucosa especially nasal epithelium is well known as the first-line barrier of air-borne pathogens. High levels of reactive oxygen species (ROS) are detected in in vitro cultured human epithelial cells and in vivo lung. With identification of NADPH oxidase (Nox) system of respiratory epithelium, the antimicrobial role of ROS has been studied. Duox2 is the most abundant Nox isoform and produces the regulated amount of ROS in respiratory epithelium. Duox2-derived ROS are involved in antiviral innate immune responses but more studies are needed to verify the mechanism. In respiratory epithelium, Duox2-derived ROS is critical for recognition of virus through families retinoic acid-inducible gene-I (RIG-I) and melanoma differentiation-associated protein 5 (MDA5) at the early stage of antiviral innate immune responses. Various secreted interferons (IFNs) play essential roles for antiviral host defense by downstream cell signaling, and transcription of IFN-stimulated genes is started to suppress viral replication. Type I and type III IFNs are verified more responsible for influenza A virus (IAV) infection in respiratory epithelium and Duox2 is required to regulate IFN-related immune responses. Transient overexpression of Duox2 using cationic polymer polyethylenimine (PEI) induces secretion of type I and type III IFNs and significantly attenuated IAV replication in respiratory epithelium. Here, we discuss Duox2-mediated antiviral innate immune responses and the role of Duox2 as a mucosal vaccine to resist respiratory viral infection.

Ursodeoxycholic Acid Induces Death Receptor-mediated Apoptosis in Prostate Cancer Cells

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Lee, Won Sup; Jung, Ji Hyun; Panchanathan, Radha; Yun, Jeong Won; Kim, Dong Hoon; Kim, Hye Jung; Kim, Gon Sup; Ryu, Chung Ho; Shin, Sung Chul; Hong, Soon Chan; Choi, Yung Hyun; Jung, Jin-Myung

2017-01-01

Background Bile acids have anti-cancer properties in a certain types of cancers. We determined anticancer activity and its underlying molecular mechanism of ursodeoxycholic acid (UDCA) in human DU145 prostate cancer cells. Methods Cell viability was measured with an MTT assay. UDCA-induced apoptosis was determined with flow cytometric analysis. The expression levels of apoptosis-related signaling proteins were examined with Western blotting. Results UDCA treatment significantly inhibited cell growth of DU145 in a dose-dependent manner. It induced cellular shrinkage and cytoplasmic blebs and accumulated the cells with sub-G1 DNA contents. Moreover, UDCA activated caspase 8, suggesting that UDCA-induced apoptosis is associated with extrinsic pathway. Consistent to this finding, UDCA increased the expressions of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor, death receptor 4 (DR4) and death receptor 5 (DR5), and TRAIL augmented the UDCA-induced cell death in DU145 cells. In addition, UDCA also increased the expressions of Bax and cytochrome c and decreased the expression of Bcl-xL in DU145 cells. This finding suggests that UDCA-induced apoptosis may be involved in intrinsic pathway. Conclusions UDCA induces apoptosis via extrinsic pathway as well as intrinsic pathway in DU145 prostate cancer cells. UDCA may be a promising anti-cancer agent against prostate cancer. PMID:28382282

ATL9, a RING zinc finger protein with E3 ubiquitin ligase activity implicated in chitin- and NADPH oxidase-mediated defense responses.

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Marta Berrocal-Lobo

2010-12-01

Full Text Available Pathogen associated molecular patterns (PAMPs are signals detected by plants that activate basal defenses. One of these PAMPs is chitin, a carbohydrate present in the cell walls of fungi and in insect exoskeletons. Previous work has shown that chitin treatment of Arabidopsis thaliana induced defense-related genes in the absence of a pathogen and that the response was independent of the salicylic acid (SA, jasmonic acid (JA and ethylene (ET signaling pathways. One of these genes is ATL9 ( = ATL2G, which encodes a RING zinc-finger like protein. In the current work we demonstrate that ATL9 has E3 ubiquitin ligase activity and is localized to the endoplasmic reticulum. The expression pattern of ATL9 is positively correlated with basal defense responses against Golovinomyces cichoracearum, a biotrophic fungal pathogen. The basal levels of expression and the induction of ATL9 by chitin, in wild type plants, depends on the activity of NADPH oxidases suggesting that chitin-mediated defense response is NADPH oxidase dependent. Although ATL9 expression is not induced by treatment with known defense hormones (SA, JA or ET, full expression in response to chitin is compromised slightly in mutants where ET- or SA-dependent signaling is suppressed. Microarray analysis of the atl9 mutant revealed candidate genes that appear to act downstream of ATL9 in chitin-mediated defenses. These results hint at the complexity of chitin-mediated signaling and the potential interplay between elicitor-mediated signaling, signaling via known defense pathways and the oxidative burst.

Synergism in the effect of prior jasmonic acid application on herbivore-induced volatile emission by Lima bean plants: transcription of a monoterpene synthase gene and volatile emission

NARCIS (Netherlands)

Menzel, T.R.; Weldegergis, B.T.; David, A.; Boland, W.; Gols, R.; Loon, van J.J.A.; Dicke, M.

2014-01-01

Jasmonic acid (JA) plays a central role in induced plant defence e.g. by regulating the biosynthesis of herbivore-induced plant volatiles that mediate the attraction of natural enemies of herbivores. Moreover, exogenous application of JA can be used to elicit plant defence responses similar to those

Induced ER-chaperones regulate a novel receptor-like kinase to mediate a viral innate immune response

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Caplan, Jeffrey L.; Zhu, Xiaohong; Mamillapalli, Padmavathi; Marathe, Rajendra; Anandalakshmi, Radhamani; Dinesh-Kumar, S. P.

2009-01-01

Summary The plant innate immune response requires a rapid, global reprogramming of cellular processes. Here we employed two complementary proteomic methods, two-dimensional differential in-gel electrophoresis (2D-DIGE) and iTRAQ, to identify differentially regulated proteins early during a defense response. Besides defense-related proteins, the constituents of the largest category of up-regulated proteins were cytoplasmic- and endoplasmic reticulum (ER)-residing molecular chaperones. Silencing of ER-resident protein disulfide isomerases, NbERp57 and NbP5, and the calreticulins, NbCRT2 and NbCRT3, lead to a partial loss of N immune receptor-mediated defense against Tobacco mosaic virus (TMV). Furthermore, NbCRT2 and NbCRT3 are required for the expression of a novel induced receptor-like kinase (IRK). IRK is a plasma membrane-localized protein required for the N-mediated hypersensitive response programmed cell death (HR-PCD) and resistance to TMV. These data support a model in which ER-resident chaperones are required for the accumulation of membrane bound or secreted proteins that are necessary for innate immunity. PMID:19917500

Distinct gut-derived lactic acid bacteria elicit divergent dendritic cell-mediated NK cell responses

DEFF Research Database (Denmark)

Fink, Lisbeth Nielsen; Zeuthen, Louise Hjerrild; Christensen, Hanne

2007-01-01

Lactic acid bacteria (LAB) are abundant in the gastrointestinal tract where they continuously regulate the immune system. NK cells are potently activated by dendritic cells (DCs) matured by inflammatory stimuli, and NK cells are present in the gut epithelium and in mesenteric lymph nodes......, but it is not known how NK-DC interactions are affected by the predominantly non-pathogenic LAB. We demonstrate that human DCs exposed to different strains of gut-derived LAB consistently induce proliferation, cytotoxicity and activation markers in autologous NK cells. On the contrary, strains of LAB differ greatly...... in their ability to induce DC-dependent IFN-gamma production by NK cells. This suggests that DCs stimulated by gut LAB may expand the pool of NK cells and increase their cytotoxic potential. Specific LAB, inducing high levels of IL-12 in DCs, may promote amplification of a type-1 response via potent stimulation...

Unfolded protein response (UPR) signaling regulates arsenic trioxide-mediated macrophage innate immune function disruption

International Nuclear Information System (INIS)

Srivastava, Ritesh K.; Li, Changzhao; Chaudhary, Sandeep C.; Ballestas, Mary E.; Elmets, Craig A.; Robbins, David J.; Matalon, Sadis; Deshane, Jessy S.; Afaq, Farrukh; Bickers, David R.; Athar, Mohammad

2013-01-01

Arsenic exposure is known to disrupt innate immune functions in humans and in experimental animals. In this study, we provide a mechanism by which arsenic trioxide (ATO) disrupts macrophage functions. ATO treatment of murine macrophage cells diminished internalization of FITC-labeled latex beads, impaired clearance of phagocytosed fluorescent bacteria and reduced secretion of pro-inflammatory cytokines. These impairments in macrophage functions are associated with ATO-induced unfolded protein response (UPR) signaling pathway characterized by the enhancement in proteins such as GRP78, p-PERK, p-eIF2α, ATF4 and CHOP. The expression of these proteins is altered both at transcriptional and translational levels. Pretreatment with chemical chaperon, 4-phenylbutyric acid (PBA) attenuated the ATO-induced activation in UPR signaling and afforded protection against ATO-induced disruption of macrophage functions. This treatment also reduced ATO-mediated reactive oxygen species (ROS) generation. Interestingly, treatment with antioxidant N-acetylcysteine (NAC) prior to ATO exposure, not only reduced ROS production and UPR signaling but also improved macrophage functions. These data demonstrate that UPR signaling and ROS generation are interdependent and are involved in the arsenic-induced pathobiology of macrophage. These data also provide a novel strategy to block the ATO-dependent impairment in innate immune responses. - Highlights: • Inorganic arsenic to humans and experimental animals disrupt innate immune responses. • The mechanism underlying arsenic impaired macrophage functions involves UPR signaling. • Chemical chaperon attenuates arsenic-mediated macrophage function impairment. • Antioxidant, NAC blocks impairment in arsenic-treated macrophage functions

Unfolded protein response (UPR) signaling regulates arsenic trioxide-mediated macrophage innate immune function disruption

Energy Technology Data Exchange (ETDEWEB)

Srivastava, Ritesh K.; Li, Changzhao; Chaudhary, Sandeep C. [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States); Ballestas, Mary E. [Department of Pediatrics Infectious Disease, Children' s of Alabama, School of Medicine, University of Alabama at Birmingham, AL (United States); Elmets, Craig A. [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States); Robbins, David J. [Department of Surgery, Molecular Oncology Program, Miller School of Medicine, University of Miami, Miami (United States); Matalon, Sadis [Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL (United States); Deshane, Jessy S. [Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, AL (United States); Afaq, Farrukh [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States); Bickers, David R. [Department of Dermatology, Columbia University Medical Center, New York (United States); Athar, Mohammad, E-mail: mathar@uab.edu [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States)

2013-11-01

Arsenic exposure is known to disrupt innate immune functions in humans and in experimental animals. In this study, we provide a mechanism by which arsenic trioxide (ATO) disrupts macrophage functions. ATO treatment of murine macrophage cells diminished internalization of FITC-labeled latex beads, impaired clearance of phagocytosed fluorescent bacteria and reduced secretion of pro-inflammatory cytokines. These impairments in macrophage functions are associated with ATO-induced unfolded protein response (UPR) signaling pathway characterized by the enhancement in proteins such as GRP78, p-PERK, p-eIF2α, ATF4 and CHOP. The expression of these proteins is altered both at transcriptional and translational levels. Pretreatment with chemical chaperon, 4-phenylbutyric acid (PBA) attenuated the ATO-induced activation in UPR signaling and afforded protection against ATO-induced disruption of macrophage functions. This treatment also reduced ATO-mediated reactive oxygen species (ROS) generation. Interestingly, treatment with antioxidant N-acetylcysteine (NAC) prior to ATO exposure, not only reduced ROS production and UPR signaling but also improved macrophage functions. These data demonstrate that UPR signaling and ROS generation are interdependent and are involved in the arsenic-induced pathobiology of macrophage. These data also provide a novel strategy to block the ATO-dependent impairment in innate immune responses. - Highlights: • Inorganic arsenic to humans and experimental animals disrupt innate immune responses. • The mechanism underlying arsenic impaired macrophage functions involves UPR signaling. • Chemical chaperon attenuates arsenic-mediated macrophage function impairment. • Antioxidant, NAC blocks impairment in arsenic-treated macrophage functions.

Ethylene signaling renders the jasmonate response of Arabidopsis insensitive to future suppression by salicylic Acid.

Science.gov (United States)

Leon-Reyes, Antonio; Du, Yujuan; Koornneef, Annemart; Proietti, Silvia; Körbes, Ana P; Memelink, Johan; Pieterse, Corné M J; Ritsema, Tita

2010-02-01

Cross-talk between jasmonate (JA), ethylene (ET), and Salicylic acid (SA) signaling is thought to operate as a mechanism to fine-tune induced defenses that are activated in response to multiple attackers. Here, 43 Arabidopsis genotypes impaired in hormone signaling or defense-related processes were screened for their ability to express SA-mediated suppression of JA-responsive gene expression. Mutant cev1, which displays constitutive expression of JA and ET responses, appeared to be insensitive to SA-mediated suppression of the JA-responsive marker genes PDF1.2 and VSP2. Accordingly, strong activation of JA and ET responses by the necrotrophic pathogens Botrytis cinerea and Alternaria brassicicola prior to SA treatment counteracted the ability of SA to suppress the JA response. Pharmacological assays, mutant analysis, and studies with the ET-signaling inhibitor 1-methylcyclopropene revealed that ET signaling renders the JA response insensitive to subsequent suppression by SA. The APETALA2/ETHYLENE RESPONSE FACTOR transcription factor ORA59, which regulates JA/ET-responsive genes such as PDF1.2, emerged as a potential mediator in this process. Collectively, our results point to a model in which simultaneous induction of the JA and ET pathway renders the plant insensitive to future SA-mediated suppression of JA-dependent defenses, which may prioritize the JA/ET pathway over the SA pathway during multi-attacker interactions.

An accessory to the 'Trinity': SR-As are essential pathogen sensors of extracellular dsRNA, mediating entry and leading to subsequent type I IFN responses.

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Stephanie J DeWitte-Orr

2010-03-01

Full Text Available Extracellular RNA is becoming increasingly recognized as a signaling molecule. Virally derived double stranded (dsRNA released into the extracellular space during virus induced cell lysis acts as a powerful inducer of classical type I interferon (IFN responses; however, the receptor that mediates this response has not been identified. Class A scavenger receptors (SR-As are likely candidates due to their cell surface expression and ability to bind nucleic acids. In this study, we investigated a possible role for SR-As in mediating type I IFN responses induced by extracellular dsRNA in fibroblasts, a predominant producer of IFNbeta. Fibroblasts were found to express functional SR-As, even SR-A species thought to be macrophage specific. SR-A specific competitive ligands significantly blocked extracellular dsRNA binding, entry and subsequent interferon stimulated gene (ISG induction. Candidate SR-As were systematically investigated using RNAi and the most dramatic inhibition in responses was observed when all candidate SR-As were knocked down in unison. Partial inhibition of dsRNA induced antiviral responses was observed in vivo in SR-AI/II(-/- mice compared with WT controls. The role of SR-As in mediating extracellular dsRNA entry and subsequent induced antiviral responses was observed in both murine and human fibroblasts. SR-As appear to function as 'carriers', facilitating dsRNA entry and delivery to the established dsRNA sensing receptors, specifically TLR3, RIGI and MDA-5. Identifying SR-As as gatekeepers of the cell, mediating innate antiviral responses, represents a novel function for this receptor family and provides insight into how cells recognize danger signals associated with lytic virus infections. Furthermore, the implications of a cell surface receptor capable of recognizing extracellular RNA may exceed beyond viral immunity to mediating other important innate immune functions.

The Arabidopsis mediator complex subunits MED16, MED14, and MED2 regulate mediator and RNA polymerase II recruitment to CBF-responsive cold-regulated genes.

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Hemsley, Piers A; Hurst, Charlotte H; Kaliyadasa, Ewon; Lamb, Rebecca; Knight, Marc R; De Cothi, Elizabeth A; Steele, John F; Knight, Heather

2014-01-01

The Mediator16 (MED16; formerly termed SENSITIVE TO FREEZING6 [SFR6]) subunit of the plant Mediator transcriptional coactivator complex regulates cold-responsive gene expression in Arabidopsis thaliana, acting downstream of the C-repeat binding factor (CBF) transcription factors to recruit the core Mediator complex to cold-regulated genes. Here, we use loss-of-function mutants to show that RNA polymerase II recruitment to CBF-responsive cold-regulated genes requires MED16, MED2, and MED14 subunits. Transcription of genes known to be regulated via CBFs binding to the C-repeat motif/drought-responsive element promoter motif requires all three Mediator subunits, as does cold acclimation-induced freezing tolerance. In addition, these three subunits are required for low temperature-induced expression of some other, but not all, cold-responsive genes, including genes that are not known targets of CBFs. Genes inducible by darkness also required MED16 but required a different combination of Mediator subunits for their expression than the genes induced by cold. Together, our data illustrate that plants control transcription of specific genes through the action of subsets of Mediator subunits; the specific combination defined by the nature of the stimulus but also by the identity of the gene induced.

Antagonist effects of veratric acid against UVB-induced cell damages.

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Shin, Seoung Woo; Jung, Eunsun; Kim, Seungbeom; Lee, Kyung-Eun; Youm, Jong-Kyung; Park, Deokhoon

2013-05-10

Ultraviolet (UV) radiation induces DNA damage, oxidative stress, and inflammatory processes in human epidermis, resulting in inflammation, photoaging, and photocarcinogenesis. Adequate protection of skin against the harmful effect of UV irradiation is essential. In recent years naturally occurring herbal compounds such as phenolic acids, flavonoids, and high molecular weight polyphenols have gained considerable attention as beneficial protective agents. The simple phenolic veratric acid (VA, 3,4-dimethoxybenzoic acid) is one of the major benzoic acid derivatives from vegetables and fruits and it also occurs naturally in medicinal mushrooms which have been reported to have anti-inflammatory and anti-oxidant activities. However, it has rarely been applied in skin care. This study, therefore, aimed to explore the possible roles of veratric acid in protection against UVB-induced damage in HaCaT cells. Results showed that veratric acid can attenuate cyclobutane pyrimidine dimers (CPDs) formation, glutathione (GSH) depletion and apoptosis induced by UVB. Furthermore, veratric acid had inhibitory effects on the UVB-induced release of the inflammatory mediators such as IL-6 and prostaglandin-E2. We also confirmed the safety and clinical efficacy of veratric acid on human skin. Overall, results demonstrated significant benefits of veratric acid on the protection of keratinocyte against UVB-induced injuries and suggested its potential use in skin photoprotection.

IL-27 induces a pro-inflammatory response in human fetal membranes mediating preterm birth.

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Yin, Nanlin; Wang, Hanbing; Zhang, Hua; Ge, Huisheng; Tan, Bing; Yuan, Yu; Luo, Xiaofang; Olson, David M; Baker, Philip N; Qi, Hongbo

2017-09-01

Inflammation at the maternal-fetal interface has been shown to be involved in the pathogenesis of preterm birth. Interleukin 27 (IL-27), a heterodimeric cytokine, is known to mediate an inflammatory response in some pregnancy complications. In this study, we aimed to determine whether IL-27 could induce an inflammatory reaction at the maternal-fetal interface that would mediate the onset of preterm birth. We found elevated expression of IL-27 in human peripheral serum and elevated expression of its specific receptor (wsx-1) on fetal membranes in cases of preterm birth. Moreover, the release of inflammatory markers (CXCL10, IFN-γ, MCP-1, IL-6, IL-1β and TNF-α), especially CXCL10, was markedly augmented upon stimulation of IL-27 in the fetal membranes. Additionally, IL-27 and IFN-γ cooperated to amplify the expression of CXCL10 in the fetal membranes. Moreover, the production of CXCL10 was increased in IL-27-treated fetal membrane through JNK, PI3K or Erk signaling pathways. Finally, MMP2 and MMP9 were activated by IL-27 in human fetal membranes, which may be related to the onset of preterm premature rupture of membranes (pPROM). In conclusion, for the first time, we reported that the aberrant expression of IL-27 could mediate an excessive inflammatory response in fetal membranes through the JNK, PI3K or Erk signaling pathways, which contributes to preterm birth. Copyright © 2017 Elsevier B.V. All rights reserved.

Abscisic acid promotes proteasome-mediated degradation of the transcription coactivator NPR1 in Arabidopsis thaliana.

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Ding, Yezhang; Dommel, Matthew; Mou, Zhonglin

2016-04-01

Proteasome-mediated turnover of the transcription coactivator NPR1 is pivotal for efficient activation of the broad-spectrum plant immune responses known as localized acquired resistance (LAR) and systemic acquired resistance (SAR) in adjacent and systemic tissues, respectively, and requires the CUL3-based E3 ligase and its adaptor proteins, NPR3 and NPR4, which are receptors for the signaling molecule salicylic acid (SA). It has been shown that SA prevents NPR1 turnover under non-inducing and LAR/SAR-inducing conditions, but how cellular NPR1 homeostasis is maintained remains unclear. Here, we show that the phytohormone abscisic acid (ABA) and SA antagonistically influence cellular NPR1 protein levels. ABA promotes NPR1 degradation via the CUL3(NPR) (3/) (NPR) (4) complex-mediated proteasome pathway, whereas SA may protect NPR1 from ABA-promoted degradation through phosphorylation. Furthermore, we demonstrate that the timing and strength of SA and ABA signaling are critical in modulating NPR1 accumulation and target gene expression. Perturbing ABA or SA signaling in adjacent tissues alters the temporal dynamic pattern of NPR1 accumulation and target gene transcription. Finally, we show that sequential SA and ABA treatment leads to dynamic changes in NPR1 protein levels and target gene expression. Our results revealed a tight correlation between sequential SA and ABA signaling and dynamic changes in NPR1 protein levels and NPR1-dependent transcription in plant immune responses. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

Proteomic investigation into betulinic acid-induced apoptosis of human cervical cancer HeLa cells.

Science.gov (United States)

Xu, Tao; Pang, Qiuying; Zhou, Dong; Zhang, Aiqin; Luo, Shaman; Wang, Yang; Yan, Xiufeng

2014-01-01

Betulinic acid is a pentacyclic triterpenoid that exhibits anticancer functions in human cancer cells. This study provides evidence that betulinic acid is highly effective against the human cervical cancer cell line HeLa by inducing dose- and time-dependent apoptosis. The apoptotic process was further investigated using a proteomics approach to reveal protein expression changes in HeLa cells following betulinic acid treatment. Proteomic analysis revealed that there were six up- and thirty down-regulated proteins in betulinic acid-induced HeLa cells, and these proteins were then subjected to functional pathway analysis using multiple analysis software. UDP-glucose 6-dehydrogenase, 6-phosphogluconate dehydrogenase decarboxylating, chain A Horf6-a novel human peroxidase enzyme that involved in redox process, was found to be down-regulated during the apoptosis process of the oxidative stress response pathway. Consistent with our results at the protein level, an increase in intracellular reactive oxygen species was observed in betulinic acid-treated cells. The proteins glucose-regulated protein and cargo-selection protein TIP47, which are involved in the endoplasmic reticulum pathway, were up-regulated by betulinic acid treatment. Meanwhile, 14-3-3 family proteins, including 14-3-3β and 14-3-3ε, were down-regulated in response to betulinic acid treatment, which is consistent with the decrease in expression of the target genes 14-3-3β and 14-3-3ε. Furthermore, it was found that the antiapoptotic bcl-2 gene was down-regulated while the proapoptotic bax gene was up-regulated after betulinic acid treatment in HeLa cells. These results suggest that betulinic acid induces apoptosis of HeLa cells by triggering both the endoplasmic reticulum pathway and the ROS-mediated mitochondrial pathway.

Ursodeoxycholic acid protects cardiomyocytes against cobalt chloride induced hypoxia by regulating transcriptional mediator of cells stress hypoxia inducible factor 1α and p53 protein.

Science.gov (United States)

Mohamed, Anis Syamimi; Hanafi, Noorul Izzati; Sheikh Abdul Kadir, Siti Hamimah; Md Noor, Julina; Abdul Hamid Hasani, Narimah; Ab Rahim, Sharaniza; Siran, Rosfaiizah

2017-10-01

In hepatocytes, ursodeoxycholic acid (UDCA) activates cell signalling pathways such as p53, intracellular calcium ([Ca 2+ ] i ), and sphingosine-1-phosphate (S1P)-receptor via Gα i -coupled-receptor. Recently, UDCA has been shown to protect the heart against hypoxia-reoxygenation injury. However, it is not clear whether UDCA cardioprotection against hypoxia acts through a transcriptional mediator of cells stress, HIF-1α and p53. Therefore, in here, we aimed to investigate whether UDCA could protect cardiomyocytes (CMs) against hypoxia by regulating expression of HIF-1α, p53, [Ca 2+ ] i , and S1P-Gα i -coupled-receptor. Cardiomyocytes were isolated from newborn rats (0-2 days), and hypoxia was induced by using cobalt chloride (CoCl 2 ). Cardiomyocytes were treated with UDCA and cotreated with either FTY720 (S1P-receptor agonist) or pertussis toxin (PTX; Gα i inhibitor). Cells were subjected for proliferation assay, beating frequency, QuantiGene Plex assay, western blot, immunofluorescence, and calcium imaging. Our findings showed that UDCA counteracted the effects of CoCl 2 on cell viability, beating frequency, HIF-1α, and p53 protein expression. We found that these cardioprotection effects of UDCA were similar to FTY720, S1P agonist. Furthermore, we observed that UDCA protects CMs against CoCl 2 -induced [Ca 2+ ] i dynamic alteration. Pharmacological inhibition of the Gα i -sensitive receptor did not abolish the cardioprotection of UDCA against CoCl 2 detrimental effects, except for cell viability and [Ca 2+ ] i . Pertussis toxin is partially effective in inhibiting UDCA protection against CoCl 2 effects on CM cell viability. Interestingly, PTX fully inhibits UDCA cardioprotection on CoCl 2 -induced [Ca 2+ ] i dynamic changes. We conclude that UDCA cardioprotection against CoCl 2 -induced hypoxia is similar to FTY720, and its actions are not fully mediated by the Gα i -coupled protein sensitive pathways. Ursodeoxycholic acid is the most hydrophilic bile

Effect of glucocorticosteroid treatment on ovalbumin-induced IgE-mediated immediate and late allergic response in guinea pig.

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Andersson, P; Brange, C; von Kogerer, B; Sonmark, B; Stahre, G

1988-01-01

The effect of glucocorticosteroid (GCS) treatment on ovalbumine-induced IgE-mediated immediate and late allergic response was studied in sensitized guinea pigs. The results show that the GCS budesonide (BUD) inhibits the allergen-induced IgE-mediated immediate and late bronchial obstruction. The effect on the early reaction is correlated to the inhibition of leukotrienes and histamine release. The importance of mediator release inhibition for the antianaphylactic effect of GCS is discussed. In examining the effect on the late reaction, it was found that BUD had to be present during the early reaction but did not inhibit the early reaction. Furthermore, the effect on the late reaction was correlated to the inhibition of vascular leakage but not to the infiltration of inflammatory cells as examined in bronchoalveolar lavage. The results indicate that some triggering factors important for the development of the late reaction are released during the early reaction. Inhibition of the release of that factor or the activation of inflammatory cells by that factor might be the mechanism behind the antiinflammatory activities of GCS.

Suppressive effects of lysozyme on polyphosphate-mediated vascular inflammatory responses

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Chung, Jiwoo [College of Pharmacy, CMRI, Research Institute of Pharmaceutical Sciences, BK21 Plus KNU Multi-Omics Based Creative Drug Research Team, Kyungpook National University, Daegu 41566 (Korea, Republic of); Ku, Sae-Kwang [Department of Anatomy and Histology, College of Korean Medicine, Daegu Haany University, Gyeongsan 38610 (Korea, Republic of); Lee, Suyeon [College of Pharmacy, CMRI, Research Institute of Pharmaceutical Sciences, BK21 Plus KNU Multi-Omics Based Creative Drug Research Team, Kyungpook National University, Daegu 41566 (Korea, Republic of); Bae, Jong-Sup, E-mail: baejs@knu.ac.kr [College of Pharmacy, CMRI, Research Institute of Pharmaceutical Sciences, BK21 Plus KNU Multi-Omics Based Creative Drug Research Team, Kyungpook National University, Daegu 41566 (Korea, Republic of)

2016-06-10

Lysozyme, found in relatively high concentration in blood, saliva, tears, and milk, protects us from the ever-present danger of bacterial infection. Previous studies have reported proinflammatory responses of endothelial cells to the release of polyphosphate(PolyP). In this study, we examined the anti-inflammatory responses and mechanisms of lysozyme and its effects on PolyP-induced septic activities in human umbilical vein endothelial cells (HUVECs) and mice. The survival rates, septic biomarker levels, behavior of human neutrophils, and vascular permeability were determined in PolyP-activated HUVECs and mice. Lysozyme suppressed the PolyP-mediated vascular barrier permeability, upregulation of inflammatory biomarkers, adhesion/migration of leukocytes, and activation and/or production of nuclear factor-κB, tumor necrosis factor-α, and interleukin-6. Furthermore, lysozyme demonstrated protective effects on PolyP-mediated lethal death and the levels of the related septic biomarkers. Therefore, these results indicated the therapeutic potential of lysozyme on various systemic inflammatory diseases, such as sepsis or septic shock. -- Highlights: •PolyP is shown to be an important mediator of vascular inflammation. •Lysozyme inhibited PolyP-mediated hyperpermeability. •Lysozyme inhibited PolyP-mediated septic response. •Lysozyme reduced PolyP-induced septic mortality.

Suppressive effects of lysozyme on polyphosphate-mediated vascular inflammatory responses

International Nuclear Information System (INIS)

Chung, Jiwoo; Ku, Sae-Kwang; Lee, Suyeon; Bae, Jong-Sup

2016-01-01

Lysozyme, found in relatively high concentration in blood, saliva, tears, and milk, protects us from the ever-present danger of bacterial infection. Previous studies have reported proinflammatory responses of endothelial cells to the release of polyphosphate(PolyP). In this study, we examined the anti-inflammatory responses and mechanisms of lysozyme and its effects on PolyP-induced septic activities in human umbilical vein endothelial cells (HUVECs) and mice. The survival rates, septic biomarker levels, behavior of human neutrophils, and vascular permeability were determined in PolyP-activated HUVECs and mice. Lysozyme suppressed the PolyP-mediated vascular barrier permeability, upregulation of inflammatory biomarkers, adhesion/migration of leukocytes, and activation and/or production of nuclear factor-κB, tumor necrosis factor-α, and interleukin-6. Furthermore, lysozyme demonstrated protective effects on PolyP-mediated lethal death and the levels of the related septic biomarkers. Therefore, these results indicated the therapeutic potential of lysozyme on various systemic inflammatory diseases, such as sepsis or septic shock. -- Highlights: •PolyP is shown to be an important mediator of vascular inflammation. •Lysozyme inhibited PolyP-mediated hyperpermeability. •Lysozyme inhibited PolyP-mediated septic response. •Lysozyme reduced PolyP-induced septic mortality.

Rhamnolipids elicit defense responses and induce disease resistance against biotrophic, hemibiotrophic, and necrotrophic pathogens that require different signaling pathways in Arabidopsis and highlight a central role for salicylic acid.

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Sanchez, Lisa; Courteaux, Barbara; Hubert, Jane; Kauffmann, Serge; Renault, Jean-Hugues; Clément, Christophe; Baillieul, Fabienne; Dorey, Stéphan

2012-11-01

Plant resistance to phytopathogenic microorganisms mainly relies on the activation of an innate immune response usually launched after recognition by the plant cells of microbe-associated molecular patterns. The plant hormones, salicylic acid (SA), jasmonic acid, and ethylene have emerged as key players in the signaling networks involved in plant immunity. Rhamnolipids (RLs) are glycolipids produced by bacteria and are involved in surface motility and biofilm development. Here we report that RLs trigger an immune response in Arabidopsis (Arabidopsis thaliana) characterized by signaling molecules accumulation and defense gene activation. This immune response participates to resistance against the hemibiotrophic bacterium Pseudomonas syringae pv tomato, the biotrophic oomycete Hyaloperonospora arabidopsidis, and the necrotrophic fungus Botrytis cinerea. We show that RL-mediated resistance involves different signaling pathways that depend on the type of pathogen. Ethylene is involved in RL-induced resistance to H. arabidopsidis and to P. syringae pv tomato whereas jasmonic acid is essential for the resistance to B. cinerea. SA participates to the restriction of all pathogens. We also show evidence that SA-dependent plant defenses are potentiated by RLs following challenge by B. cinerea or P. syringae pv tomato. These results highlight a central role for SA in RL-mediated resistance. In addition to the activation of plant defense responses, antimicrobial properties of RLs are thought to participate in the protection against the fungus and the oomycete. Our data highlight the intricate mechanisms involved in plant protection triggered by a new type of molecule that can be perceived by plant cells and that can also act directly onto pathogens.

Inhibitory effects of omega-3 fatty acids on injury-induced epidermal growth factor receptor transactivation contribute to delayed wound healing.

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Turk, Harmony F; Monk, Jennifer M; Fan, Yang-Yi; Callaway, Evelyn S; Weeks, Brad; Chapkin, Robert S

2013-05-01

Epidermal growth factor receptor (EGFR)-mediated signaling is required for optimal intestinal wound healing. Since n-3 polyunsaturated fatty acids (PUFA), specifically docosahexaenoic acid (DHA), alter EGFR signaling and suppress downstream activation of key signaling pathways, we hypothesized that DHA would be detrimental to the process of intestinal wound healing. Using a mouse immortalized colonocyte model, DHA uniquely reduced EGFR ligand-induced receptor activation, whereas DHA and its metabolic precursor eicosapentaenoic acid (EPA) reduced wound-induced EGFR transactivation compared with control (no fatty acid or linoleic acid). Under wounding conditions, the suppression of EGFR activation was associated with a reduction in downstream activation of cytoskeletal remodeling proteins (PLCγ1, Rac1, and Cdc42). Subsequently, DHA and EPA reduced cell migration in response to wounding. Mice were fed a corn oil-, DHA-, or EPA-enriched diet prior to intestinal wounding (2.5% dextran sodium sulfate for 5 days followed by termination after 0, 3, or 6 days of recovery). Mortality was increased in EPA-fed mice and colonic histological injury scores were increased in EPA- and DHA-fed mice compared with corn oil-fed (control) mice. Although kinetics of colonic EGFR activation and downstream signaling (PLCγ1, Rac1, and Cdc42) were delayed by both n-3 PUFA, colonic repair was increased in EPA- relative to DHA-fed mice. These results indicate that, during the early response to intestinal wounding, DHA and EPA uniquely delay the activation of key wound-healing processes in the colon. This effect is mediated, at least in part, via suppression of EGFR-mediated signaling and downstream cytoskeletal remodeling.

Omega-3 polyunsaturated fatty acid attenuates the inflammatory response by modulating microglia polarization through SIRT1-mediated deacetylation of the HMGB1/NF-κB pathway following experimental traumatic brain injury.

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Chen, Xiangrong; Chen, Chunnuan; Fan, Sining; Wu, Shukai; Yang, Fuxing; Fang, Zhongning; Fu, Huangde; Li, Yasong

2018-04-20

Microglial polarization and the subsequent neuroinflammatory response are contributing factors for traumatic brain injury (TBI)-induced secondary injury. High mobile group box 1 (HMGB1) mediates the activation of the NF-κB pathway, and it is considered to be pivotal in the late neuroinflammatory response. Activation of the HMGB1/NF-κB pathway is closely related to HMGB1 acetylation, which is regulated by the sirtuin (SIRT) family of proteins. Omega-3 polyunsaturated fatty acids (ω-3 PUFA) are known to have antioxidative and anti-inflammatory effects. We previously demonstrated that ω-3 PUFA inhibited TBI-induced microglial activation and the subsequent neuroinflammatory response by regulating the HMGB1/NF-κB signaling pathway. However, no studies have elucidated if ω-3 PUFA affects the HMGB1/NF-κB pathway in a HMGB1 deacetylation of dependent SIRT1 manner, thus regulating microglial polarization and the subsequent neuroinflammatory response. The Feeney DM TBI model was adopted to induce brain injury in rats. Modified neurological severity scores, rotarod test, brain water content, and Nissl staining were employed to determine the neuroprotective effects of ω-3 PUFA supplementation. Assessment of microglia polarization and pro-inflammatory markers, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and HMGB1, were used to evaluate the neuroinflammatory responses and the anti-inflammatory effects of ω-3 PUFA supplementation. Immunofluorescent staining and western blot analysis were used to detect HMGB1 nuclear translocation, secretion, and HMGB1/NF-κB signaling pathway activation to evaluate the effects of ω-3 PUFA supplementation. The impact of SIRT1 deacetylase activity on HMGB1 acetylation and the interaction between HMGB1 and SIRT1 were assessed to evaluate anti-inflammation effects of ω-3 PUFAs, and also, whether these effects were dependent on a SIRT1-HMGB1/NF-κB axis to gain further insight into the mechanisms underlying the

Antagonist Effects of Veratric Acid against UVB-Induced Cell Damages

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Deokhoon Park

2013-05-01

Full Text Available Ultraviolet (UV radiation induces DNA damage, oxidative stress, and inflammatory processes in human epidermis, resulting in inflammation, photoaging, and photocarcinogenesis. Adequate protection of skin against the harmful effect of UV irradiation is essential. In recent years naturally occurring herbal compounds such as phenolic acids, flavonoids, and high molecular weight polyphenols have gained considerable attention as beneficial protective agents. The simple phenolic veratric acid (VA, 3,4-dimethoxybenzoic acid is one of the major benzoic acid derivatives from vegetables and fruits and it also occurs naturally in medicinal mushrooms which have been reported to have anti-inflammatory and anti-oxidant activities. However, it has rarely been applied in skin care. This study, therefore, aimed to explore the possible roles of veratric acid in protection against UVB-induced damage in HaCaT cells. Results showed that veratric acid can attenuate cyclobutane pyrimidine dimers (CPDs formation, glutathione (GSH depletion and apoptosis induced by UVB. Furthermore, veratric acid had inhibitory effects on the UVB-induced release of the inflammatory mediators such as IL-6 and prostaglandin-E2. We also confirmed the safety and clinical efficacy of veratric acid on human skin. Overall, results demonstrated significant benefits of veratric acid on the protection of keratinocyte against UVB-induced injuries and suggested its potential use in skin photoprotection.

Mediator profiles in tears during the conjunctival response induced by allergic reaction in the nasal mucosa.

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Pelikan, Zdenek

2013-01-01

The allergic reaction occurring primarily in the nasal mucosa can induce a secondary conjunctival response of an immediate (SICR), late (SLCR), or delayed (SDYCR) type in some patients with allergic conjunctivitis (AC). To investigate the concentration changes of histamine, tryptase, eosinophil cationic protein (ECP), eosinophil-derived neurotoxin (EDN), leukotrienes (LTB 4, LTC4, LTE4), myeloperoxidase (MPO), interferon-γ (IFN-γ), and interleukins (IL-2, IL-4, IL-5) in tears during the SICR, SLCR, and SDYCR. In 32 patients with AC, 11 SICR (ptears. The SICRs were associated with significant concentration changes in tears (ptears (ptears during the 32 PBS controls (p>0.1) or in the ten control patients (p>0.1). These results provide evidence for causal involvement of nasal allergy in some patients with AC, inducing secondary conjunctival response of immediate (SICR), late SLCR, or delayed SDYCR type, associated with different mediator, cytokine, and cellular profiles in the tears, suggesting involvement of different hypersensitivity mechanisms. These results also emphasize the diagnostic value of nasal allergen challenge combined with monitoring of the conjunctival response in some patients with AC.

Dietary phenolic acids reverse insulin resistance, hyperglycaemia, dyslipidaemia, inflammation and oxidative stress in high-fructose diet-induced metabolic syndrome rats.

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Ibitoye, Oluwayemisi B; Ajiboye, Taofeek O

2017-12-20

This study investigated the influence of caffeic, ferulic, gallic and protocatechuic acids on high-fructose diet-induced metabolic syndrome in rats. Oral administration of the phenolic acids significantly reversed high-fructose diet-mediated increase in body mass index and blood glucose. Furthermore, phenolic acids restored high-fructose diet-mediated alterations in metabolic hormones (insulin, leptin and adiponectin). Similarly, elevated tumour necrosis factor-α, interleukin-6 and -8 were significantly lowered. Administration of phenolic acids restored High-fructose diet-mediated increase in the levels of lipid parameters and indices of atherosclerosis, cardiac and cardiovascular diseases. High-fructose diet-mediated decrease in activities of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glucose 6-phosphate dehydrogenase) and increase in oxidative stress biomarkers (reduced glutathione, lipid peroxidation products, protein oxidation and fragmented DNA) were significantly restored by the phenolic acids. The result of this study shows protective influence of caffeic acid, ferulic acid, gallic acid and protocatechuic acid in high-fructose diet-induced metabolic syndrome.

Natural resistance to ascorbic acid induced oxidative stress is mainly mediated by catalase activity in human cancer cells and catalase-silencing sensitizes to oxidative stress

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Klingelhoeffer Christoph

2012-05-01

Full Text Available Abstract Background Ascorbic acid demonstrates a cytotoxic effect by generating hydrogen peroxide, a reactive oxygen species (ROS involved in oxidative cell stress. A panel of eleven human cancer cell lines, glioblastoma and carcinoma, were exposed to serial dilutions of ascorbic acid (5-100 mmol/L. The purpose of this study was to analyse the impact of catalase, an important hydrogen peroxide-detoxifying enzyme, on the resistance of cancer cells to ascorbic acid mediated oxidative stress. Methods Effective concentration (EC50 values, which indicate the concentration of ascorbic acid that reduced the number of viable cells by 50%, were detected with the crystal violet assay. The level of intracellular catalase protein and enzyme activity was determined. Expression of catalase was silenced by catalase-specific short hairpin RNA (sh-RNA in BT-20 breast carcinoma cells. Oxidative cell stress induced apoptosis was measured by a caspase luminescent assay. Results The tested human cancer cell lines demonstrated obvious differences in their resistance to ascorbic acid mediated oxidative cell stress. Forty-five percent of the cell lines had an EC50 > 20 mmol/L and fifty-five percent had an EC50 50 of 2.6–5.5 mmol/L, glioblastoma cells were the most susceptible cancer cell lines analysed in this study. A correlation between catalase activity and the susceptibility to ascorbic acid was observed. To study the possible protective role of catalase on the resistance of cancer cells to oxidative cell stress, the expression of catalase in the breast carcinoma cell line BT-20, which cells were highly resistant to the exposure to ascorbic acid (EC50: 94,9 mmol/L, was silenced with specific sh-RNA. The effect was that catalase-silenced BT-20 cells (BT-20 KD-CAT became more susceptible to high concentrations of ascorbic acid (50 and 100 mmol/L. Conclusions Fifty-five percent of the human cancer cell lines tested were unable to protect themselves

Anti-inflammatory effects of benfotiamine are mediated through the regulation of the arachidonic acid pathway in macrophages.

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Shoeb, Mohammad; Ramana, Kota V

2012-01-01

Benfotiamine, a lipid-soluble analogue of vitamin B1, is a potent antioxidant that is used as a food supplement for the treatment of diabetic complications. Our recent study (U.C. Yadav et al., Free Radic. Biol. Med. 48:1423-1434, 2010) indicates a novel role for benfotiamine in the prevention of bacterial endotoxin, lipopolysaccharide (LPS)-induced cytotoxicity and inflammatory response in murine macrophages. Nevertheless, it remains unclear how benfotiamine mediates anti-inflammatory effects. In this study, we investigated the anti-inflammatory role of benfotiamine in regulating arachidonic acid (AA) pathway-generated inflammatory lipid mediators in RAW264.7 macrophages. Benfotiamine prevented the LPS-induced activation of cPLA2 and release of AA metabolites such as leukotrienes, prostaglandin E2, thromboxane 2 (TXB2), and prostacyclin (PGI2) in macrophages. Further, LPS-induced expression of AA-metabolizing enzymes such as COX-2, LOX-5, TXB synthase, and PGI2 synthase was significantly blocked by benfotiamine. Furthermore, benfotiamine prevented the LPS-induced phosphorylation of ERK1/2 and expression of transcription factors NF-κB and Egr-1. Benfotiamine also prevented the LPS-induced oxidative stress and protein-HNE adduct formation. Most importantly, compared to specific COX-2 and LOX-5 inhibitors, benfotiamine significantly prevented LPS-induced macrophage death and monocyte adhesion to endothelial cells. Thus, our studies indicate that the dual regulation of the COX and LOX pathways in AA metabolism could be a novel mechanism by which benfotiamine exhibits its potential anti-inflammatory response. Copyright © 2011 Elsevier Inc. All rights reserved.

Involvement of yeast HSP90 isoforms in response to stress and cell death induced by acetic acid.

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Alexandra Silva

Full Text Available Acetic acid-induced apoptosis in yeast is accompanied by an impairment of the general protein synthesis machinery, yet paradoxically also by the up-regulation of the two isoforms of the heat shock protein 90 (HSP90 chaperone family, Hsc82p and Hsp82p. Herein, we show that impairment of cap-dependent translation initiation induced by acetic acid is caused by the phosphorylation and inactivation of eIF2α by Gcn2p kinase. A microarray analysis of polysome-associated mRNAs engaged in translation in acetic acid challenged cells further revealed that HSP90 mRNAs are over-represented in this polysome fraction suggesting preferential translation of HSP90 upon acetic acid treatment. The relevance of HSP90 isoform translation during programmed cell death (PCD was unveiled using genetic and pharmacological abrogation of HSP90, which suggests opposing roles for HSP90 isoforms in cell survival and death. Hsc82p appears to promote survival and its deletion leads to necrotic cell death, while Hsp82p is a pro-death molecule involved in acetic acid-induced apoptosis. Therefore, HSP90 isoforms have distinct roles in the control of cell fate during PCD and their selective translation regulates cellular response to acetic acid stress.

Palmitic acid mediates hypothalamic insulin resistance by altering PKC-θ subcellular localization in rodents

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Benoit, Stephen C.; Kemp, Christopher J.; Elias, Carol F.; Abplanalp, William; Herman, James P.; Migrenne, Stephanie; Lefevre, Anne-Laure; Cruciani-Guglielmacci, Céline; Magnan, Christophe; Yu, Fang; Niswender, Kevin; Irani, Boman G.; Holland, William L.; Clegg, Deborah J.

2009-01-01

Insulin signaling can be modulated by several isoforms of PKC in peripheral tissues. Here, we assessed whether one specific isoform, PKC-θ, was expressed in critical CNS regions that regulate energy balance and whether it mediated the deleterious effects of diets high in fat, specifically palmitic acid, on hypothalamic insulin activity in rats and mice. Using a combination of in situ hybridization and immunohistochemistry, we found that PKC-θ was expressed in discrete neuronal populations of the arcuate nucleus, specifically the neuropeptide Y/agouti-related protein neurons and the dorsal medial nucleus in the hypothalamus. CNS exposure to palmitic acid via direct infusion or by oral gavage increased the localization of PKC-θ to cell membranes in the hypothalamus, which was associated with impaired hypothalamic insulin and leptin signaling. This finding was specific for palmitic acid, as the monounsaturated fatty acid, oleic acid, neither increased membrane localization of PKC-θ nor induced insulin resistance. Finally, arcuate-specific knockdown of PKC-θ attenuated diet-induced obesity and improved insulin signaling. These results suggest that many of the deleterious effects of high-fat diets, specifically those enriched with palmitic acid, are CNS mediated via PKC-θ activation, resulting in reduced insulin activity. PMID:19726875

Palmitic acid mediates hypothalamic insulin resistance by altering PKC-theta subcellular localization in rodents.

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Benoit, Stephen C; Kemp, Christopher J; Elias, Carol F; Abplanalp, William; Herman, James P; Migrenne, Stephanie; Lefevre, Anne-Laure; Cruciani-Guglielmacci, Céline; Magnan, Christophe; Yu, Fang; Niswender, Kevin; Irani, Boman G; Holland, William L; Clegg, Deborah J

2009-09-01

Insulin signaling can be modulated by several isoforms of PKC in peripheral tissues. Here, we assessed whether one specific isoform, PKC-theta, was expressed in critical CNS regions that regulate energy balance and whether it mediated the deleterious effects of diets high in fat, specifically palmitic acid, on hypothalamic insulin activity in rats and mice. Using a combination of in situ hybridization and immunohistochemistry, we found that PKC-theta was expressed in discrete neuronal populations of the arcuate nucleus, specifically the neuropeptide Y/agouti-related protein neurons and the dorsal medial nucleus in the hypothalamus. CNS exposure to palmitic acid via direct infusion or by oral gavage increased the localization of PKC-theta to cell membranes in the hypothalamus, which was associated with impaired hypothalamic insulin and leptin signaling. This finding was specific for palmitic acid, as the monounsaturated fatty acid, oleic acid, neither increased membrane localization of PKC-theta nor induced insulin resistance. Finally, arcuate-specific knockdown of PKC-theta attenuated diet-induced obesity and improved insulin signaling. These results suggest that many of the deleterious effects of high-fat diets, specifically those enriched with palmitic acid, are CNS mediated via PKC-theta activation, resulting in reduced insulin activity.

Nucleic acid-induced antiviral immunity in invertebrates: an evolutionary perspective.

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Wang, Pei-Hui; Weng, Shao-Ping; He, Jian-Guo

2015-02-01

Nucleic acids derived from viral pathogens are typical pathogen associated molecular patterns (PAMPs). In mammals, the recognition of viral nucleic acids by pattern recognition receptors (PRRs), which include Toll-like receptors (TLRs) and retinoic acid-inducible gene (RIG)-I-like receptors (RLRs), induces the release of inflammatory cytokines and type I interferons (IFNs) through the activation of nuclear factor κB (NF-κB) and interferon regulatory factor (IRF) 3/7 pathways, triggering the host antiviral state. However, whether nucleic acids can induce similar antiviral immunity in invertebrates remains ambiguous. Several studies have reported that nucleic acid mimics, especially dsRNA mimic poly(I:C), can strongly induce non-specific antiviral immune responses in insects, shrimp, and oyster. This behavior shows multiple similarities to the hallmarks of mammalian IFN responses. In this review, we highlight the current understanding of nucleic acid-induced antiviral immunity in invertebrates. We also discuss the potential recognition and regulatory mechanisms that confer non-specific antiviral immunity on invertebrate hosts. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of caffeic acid phenethyl ester on Prevotella intermedia lipopolysaccharide-induced production of proinflammatory mediators in murine macrophages.

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Choi, E-Y; Choe, S-H; Hyeon, J-Y; Choi, J-I; Choi, I S; Kim, S-J

2015-12-01

Caffeic acid phenethyl ester (CAPE) has numerous potentially beneficial properties, including antioxidant, immunomodulatory and anti-inflammatory activities. However, the effect of CAPE on periodontal disease has not been studied before. This study was designed to investigate the efficacy of CAPE in ameliorating the production of proinflammatory mediators in macrophages activated by lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen implicated in periodontal disease. LPS from P. intermedia ATCC 25611 was isolated by using the standard hot phenol-water method. Culture supernatants were assayed for nitric oxide (NO), interleukin (IL)-1β and IL-6. We used real-time polymerase chain reaction to quantify inducible NO synthase, IL-1β, IL-6, heme oxygenase (HO)-1 and suppressors of cytokine signaling (SOCS) 1 mRNA expression. HO-1 protein expression and levels of signaling proteins were assessed by immunoblot analysis. DNA-binding activities of NF-κB subunits were analyzed by using the enzyme-linked immunosorbent assay-based kits. CAPE exerted significant inhibitory effects on P. intermedia LPS-induced production of NO, IL-1β and IL-6 as well as their mRNA expression in RAW264.7 cells. CAPE-induced HO-1 expression in cells activated with P. intermedia LPS, and selective inhibition of HO-1 activity by tin protoporphyrin IX attenuated the inhibitory effect of CAPE on LPS-induced NO production. CAPE did not interfere with IκB-α degradation induced by P. intermedia LPS. Instead, CAPE decreased nuclear translocation of NF-κB p65 and p50 subunits induced with LPS, and lessened LPS-induced p50 binding activity. Further, CAPE showed strong inhibitory effects on LPS-induced signal transducer and activator of transcription 1 and 3 phosphorylation. Besides, CAPE significantly elevated SOCS1 mRNA expression in P. intermedia LPS-stimulated cells. Modulation of host response by CAPE may represent an attractive strategy towards the treatment of periodontal disease

Ferulic Acid, But Not All Hydroxycinnamic Acids, Is a Novel T3SS Inducer of Ralstonia solanacearum and Promotes Its Infection Process in Host Plants under Hydroponic Condition

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Yong Zhang

2017-09-01

Full Text Available Hydroxycinnamic acids (HCAs are typical monocyclic phenylpropanoids, including cinnamic acid (Cin, coumaric acid (Cou, caffeic acid (Caf, ferulic acid (FA and their isomers, and involved in the interactions between pathogens and host plants. Here, we focused on the impact of HCAs on expression of type III secretion system (T3SS in Ralstonia solanacearum. FA significantly induced the expression of the T3SS and some type III effectors (T3Es genes in hrp-inducing medium, while did not the other HCAs. However, exogenously supplemented FA did not affect the T3SS expression in planta and the elicitation of the hypersensitive response (HR in tobacco leaves. Consistent with its central roles in pathogenicity, the FA-induced expression of the T3SS led to significant promotion on infection process of R. solanacearum in tomato plants under hydroponics cultivation. Moreover, the FA-induced expression of the T3SS was specifically mediated by the well-characterized signaling cascade PrhA-prhI/R-PrhJ-HrpG-HrpB, independent of the other known regulatory pathways. In summary, our results demonstrated that FA, a novel inducer of the T3SS in R. solanacearum, was able to promote its infection process in host plants under hydroponics condition.

Castor oil induces laxation and uterus contraction via ricinoleic acid activating prostaglandin EP3 receptors.

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Tunaru, Sorin; Althoff, Till F; Nüsing, Rolf M; Diener, Martin; Offermanns, Stefan

2012-06-05

Castor oil is one of the oldest drugs. When given orally, it has a laxative effect and induces labor in pregnant females. The effects of castor oil are mediated by ricinoleic acid, a hydroxylated fatty acid released from castor oil by intestinal lipases. Despite the wide-spread use of castor oil in conventional and folk medicine, the molecular mechanism by which ricinoleic acid acts remains unknown. Here we show that the EP(3) prostanoid receptor is specifically activated by ricinoleic acid and that it mediates the pharmacological effects of castor oil. In mice lacking EP(3) receptors, the laxative effect and the uterus contraction induced via ricinoleic acid are absent. Although a conditional deletion of the EP(3) receptor gene in intestinal epithelial cells did not affect castor oil-induced diarrhea, mice lacking EP(3) receptors only in smooth-muscle cells were unresponsive to this drug. Thus, the castor oil metabolite ricinoleic acid activates intestinal and uterine smooth-muscle cells via EP(3) prostanoid receptors. These findings identify the cellular and molecular mechanism underlying the pharmacological effects of castor oil and indicate a role of the EP(3) receptor as a target to induce laxative effects.

Gallic acid prevents nonsteroidal anti-inflammatory drug-induced gastropathy in rat by blocking oxidative stress and apoptosis.

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Pal, Chinmay; Bindu, Samik; Dey, Sumanta; Alam, Athar; Goyal, Manish; Iqbal, Mohd Shameel; Maity, Pallab; Adhikari, Susanta S; Bandyopadhyay, Uday

2010-07-15

Nonsteroidal anti-inflammatory drug (NSAID)-induced oxidative stress plays a critical role in gastric mucosal cell apoptosis and gastropathy. NSAIDs induce the generation of hydroxyl radical ((*)OH) through the release of free iron, which plays an important role in developing gastropathy. Thus, molecules having both iron-chelating and antiapoptotic properties will be beneficial in preventing NSAID-induced gastropathy. Gallic acid (GA), a polyphenolic natural product, has the capacity to chelate free iron. Here, we report that GA significantly prevents, as well as heals, NSAID-induced gastropathy. In vivo, GA blocks NSAID-mediated mitochondrial oxidative stress by preventing mitochondrial protein carbonyl formation, lipid peroxidation, and thiol depletion. In vitro, GA scavenges free radicals and blocks (*)OH-mediated oxidative damage. GA also attenuates gastric mucosal cell apoptosis in vivo as well as in vitro in cultured gastric mucosal cells as evident from the TUNEL assay. GA prevents NSAID-induced activation of caspase-9, a marker for the mitochondrial pathway of apoptosis, and restores NSAID-mediated collapse of the mitochondrial transmembrane potential and dehydrogenase activity. Thus, the inhibition of mitochondrial oxidative stress by GA is associated with the inhibition of NSAID-induced mitochondrial dysfunction and activation of apoptosis in gastric mucosal cells, which are responsible for gastric injury or gastropathy. Copyright 2010 Elsevier Inc. All rights reserved.

Capsular Polysaccharide is a Main Component of Mycoplasma ovipneumoniae in the Pathogen-Induced Toll-Like Receptor-Mediated Inflammatory Responses in Sheep Airway Epithelial Cells

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Zhongjia Jiang

2017-01-01

Full Text Available Mycoplasma ovipneumoniae (M. ovipneumoniae is characterized as an etiological agent of primary atypical pneumonia that specifically infects sheep and goat. In an attempt to better understand the pathogen-host interaction between the invading M. ovipneumoniae and airway epithelial cells, we investigated the host inflammatory responses against capsular polysaccharide (designated as CPS of M. ovipneumoniae using sheep bronchial epithelial cells cultured in an air-liquid interface (ALI model. Results showed that CPS derived from M. ovipneumoniae could activate toll-like receptor- (TLR- mediated inflammatory responses, along with an elevated expression of nuclear factor kappa B (NF-κB, activator protein-1 (AP-1, and interferon regulatory factor 3 (IRF3 as well as various inflammatory-associated mediators, representatively including proinflammatory cytokines, such as IL1β, TNFα, and IL8, and anti-inflammatory cytokines such as IL10 and TGFβ of TLR signaling cascade. Mechanistically, the CPS-induced inflammation was TLR initiated and was mediated by activations of both MyD88-dependent and MyD88-independent signaling pathways. Of importance, a blockage of CPS with specific antibody led a significant reduction of M. ovipneumoniae-induced inflammatory responses in sheep bronchial epithelial cells. These results suggested that CPS is a key virulent component of M. ovipneumoniae, which may play a crucial role in the inflammatory response induced by M. ovipneumoniae infections.

Capsular Polysaccharide is a Main Component of Mycoplasma ovipneumoniae in the Pathogen-Induced Toll-Like Receptor-Mediated Inflammatory Responses in Sheep Airway Epithelial Cells.

Science.gov (United States)

Jiang, Zhongjia; Song, Fuyang; Li, Yanan; Xue, Di; Deng, Guangcun; Li, Min; Liu, Xiaoming; Wang, Yujiong

2017-01-01

Mycoplasma ovipneumoniae ( M. ovipneumoniae ) is characterized as an etiological agent of primary atypical pneumonia that specifically infects sheep and goat. In an attempt to better understand the pathogen-host interaction between the invading M. ovipneumoniae and airway epithelial cells, we investigated the host inflammatory responses against capsular polysaccharide (designated as CPS) of M. ovipneumoniae using sheep bronchial epithelial cells cultured in an air-liquid interface (ALI) model. Results showed that CPS derived from M. ovipneumoniae could activate toll-like receptor- (TLR-) mediated inflammatory responses, along with an elevated expression of nuclear factor kappa B (NF- κ B), activator protein-1 (AP-1), and interferon regulatory factor 3 (IRF3) as well as various inflammatory-associated mediators, representatively including proinflammatory cytokines, such as IL1 β , TNF α , and IL8, and anti-inflammatory cytokines such as IL10 and TGF β of TLR signaling cascade. Mechanistically, the CPS-induced inflammation was TLR initiated and was mediated by activations of both MyD88-dependent and MyD88-independent signaling pathways. Of importance, a blockage of CPS with specific antibody led a significant reduction of M. ovipneumoniae -induced inflammatory responses in sheep bronchial epithelial cells. These results suggested that CPS is a key virulent component of M. ovipneumoniae , which may play a crucial role in the inflammatory response induced by M. ovipneumoniae infections.

Neonicotinoid insecticides induce salicylate-associated plant defense responses

Science.gov (United States)

Ford, Kevin A.; Casida, John E.; Chandran, Divya; Gulevich, Alexander G.; Okrent, Rachel A.; Durkin, Kathleen A.; Sarpong, Richmond; Bunnelle, Eric M.; Wildermuth, Mary C.

2010-01-01

Neonicotinoid insecticides control crop pests based on their action as agonists at the insect nicotinic acetylcholine receptor, which accepts chloropyridinyl- and chlorothiazolyl-analogs almost equally well. In some cases, these compounds have also been reported to enhance plant vigor and (a)biotic stress tolerance, independent of their insecticidal function. However, this mode of action has not been defined. Using Arabidopsis thaliana, we show that the neonicotinoid compounds, imidacloprid (IMI) and clothianidin (CLO), via their 6-chloropyridinyl-3-carboxylic acid and 2-chlorothiazolyl-5-carboxylic acid metabolites, respectively, induce salicylic acid (SA)-associated plant responses. SA is a phytohormone best known for its role in plant defense against pathogens and as an inducer of systemic acquired resistance; however, it can also modulate abiotic stress responses. These neonicotinoids effect a similar global transcriptional response to that of SA, including genes involved in (a)biotic stress response. Furthermore, similar to SA, IMI and CLO induce systemic acquired resistance, resulting in reduced growth of a powdery mildew pathogen. The action of CLO induces the endogenous synthesis of SA via the SA biosynthetic enzyme ICS1, with ICS1 required for CLO-induced accumulation of SA, expression of the SA marker PR1, and fully enhanced resistance to powdery mildew. In contrast, the action of IMI does not induce endogenous synthesis of SA. Instead, IMI is further bioactivated to 6-chloro-2-hydroxypyridinyl-3-carboxylic acid, which is shown here to be a potent inducer of PR1 and inhibitor of SA-sensitive enzymes. Thus, via different mechanisms, these chloropyridinyl- and chlorothiazolyl-neonicotinoids induce SA responses associated with enhanced stress tolerance. PMID:20876120

PI3K/AKT and ERK regulate retinoic acid-induced neuroblastoma cellular differentiation

Energy Technology Data Exchange (ETDEWEB)

Qiao, Jingbo [Department of Pediatric Surgery, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Paul, Pritha; Lee, Sora [Department of Pediatric Surgery, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Qiao, Lan; Josifi, Erlena; Tiao, Joshua R. [Department of Pediatric Surgery, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Chung, Dai H., E-mail: dai.chung@vanderbilt.edu [Department of Pediatric Surgery, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN 37232 (United States)

2012-08-03

Highlights: Black-Right-Pointing-Pointer Retinoic acid (RA) induces neuroblastoma cells differentiation, which is accompanied by G0/G1 cell cycle arrest. Black-Right-Pointing-Pointer RA resulted in neuroblastoma cell survival and inhibition of DNA fragmentation; this is regulated by PI3K pathway. Black-Right-Pointing-Pointer RA activates PI3K and ERK1/2 pathway; PI3K pathway mediates RA-induced neuroblastoma cell differentiation. Black-Right-Pointing-Pointer Upregulation of p21 is necessary for RA-induced neuroblastoma cell differentiation. -- Abstract: Neuroblastoma, the most common extra-cranial solid tumor in infants and children, is characterized by a high rate of spontaneous remissions in infancy. Retinoic acid (RA) has been known to induce neuroblastoma differentiation; however, the molecular mechanisms and signaling pathways that are responsible for RA-mediated neuroblastoma cell differentiation remain unclear. Here, we sought to determine the cell signaling processes involved in RA-induced cellular differentiation. Upon RA administration, human neuroblastoma cell lines, SK-N-SH and BE(2)-C, demonstrated neurite extensions, which is an indicator of neuronal cell differentiation. Moreover, cell cycle arrest occurred in G1/G0 phase. The protein levels of cyclin-dependent kinase inhibitors, p21 and p27{sup Kip}, which inhibit cell proliferation by blocking cell cycle progression at G1/S phase, increased after RA treatment. Interestingly, RA promoted cell survival during the differentiation process, hence suggesting a potential mechanism for neuroblastoma resistance to RA therapy. Importantly, we found that the PI3K/AKT pathway is required for RA-induced neuroblastoma cell differentiation. Our results elucidated the molecular mechanism of RA-induced neuroblastoma cellular differentiation, which may be important for developing novel therapeutic strategy against poorly differentiated neuroblastoma.

Concerted action of p62 and Nrf2 protects cells from palmitic acid-induced lipotoxicity

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Park, Jeong Su [Severance Biomedical Science Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Kang, Dong Hoon [Department of Life Science and Ewha Research Center for Systems Biology (Korea, Republic of); The Research Center for Cell Homeostasis, Ewha Womans University, Seoul 127-750 (Korea, Republic of); Lee, Da Hyun [Severance Biomedical Science Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Bae, Soo Han, E-mail: soohanbae@yuhs.ac [Severance Biomedical Science Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of)

2015-10-09

Nonalcoholic fatty liver disease (NAFLD), frequently associated with obesity and diabetes mellitus, is caused by the accumulation of excess fatty acids within liver cells. Palmitic acid (PA), a common saturated fatty acid found in mammals, induces the generation of reactive oxygen species (ROS) and elicits apoptotic cell death, known as lipotoxicity. However, protective mechanisms against PA-induced lipotoxicity have not been elucidated. In this study, we aimed to clarify the role of p62, an adapter protein in the autophagic process, as well as the nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway, in protecting cells from PA-induced lipotoxicity. The Nrf2-Keap1 pathway is essential for the protection of cells from oxidative stress. p62 enhances its binding to Keap1 and leads to Nrf2 activation. Here, we show that PA potentiates Keap1 degradation and thereby activates the transcription of Nrf2 target genes partially through autophagy. Furthermore, this PA-mediated Keap1 degradation depends on p62. Correspondingly, a lack of p62 attenuates the PA-mediated Nrf2 activation and increases the susceptibility of cells to oxidative stress. These results indicate that p62 plays an important role in protecting cells against lipotoxicity through Keap1 degradation-mediated Nrf2 activation. - Highlights: • PA induces Keap1 downregulation and activates Nrf2 target gene transcription. • PA-induced Keap1 degradation is partly mediated by the autophagic pathway. • PA-induced Keap1 degradation depends on p62. • Ablation of p62 exacerbates PA-mediated apoptotic cell death.

Concerted action of p62 and Nrf2 protects cells from palmitic acid-induced lipotoxicity

International Nuclear Information System (INIS)

Park, Jeong Su; Kang, Dong Hoon; Lee, Da Hyun; Bae, Soo Han

2015-01-01

Nonalcoholic fatty liver disease (NAFLD), frequently associated with obesity and diabetes mellitus, is caused by the accumulation of excess fatty acids within liver cells. Palmitic acid (PA), a common saturated fatty acid found in mammals, induces the generation of reactive oxygen species (ROS) and elicits apoptotic cell death, known as lipotoxicity. However, protective mechanisms against PA-induced lipotoxicity have not been elucidated. In this study, we aimed to clarify the role of p62, an adapter protein in the autophagic process, as well as the nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway, in protecting cells from PA-induced lipotoxicity. The Nrf2-Keap1 pathway is essential for the protection of cells from oxidative stress. p62 enhances its binding to Keap1 and leads to Nrf2 activation. Here, we show that PA potentiates Keap1 degradation and thereby activates the transcription of Nrf2 target genes partially through autophagy. Furthermore, this PA-mediated Keap1 degradation depends on p62. Correspondingly, a lack of p62 attenuates the PA-mediated Nrf2 activation and increases the susceptibility of cells to oxidative stress. These results indicate that p62 plays an important role in protecting cells against lipotoxicity through Keap1 degradation-mediated Nrf2 activation. - Highlights: • PA induces Keap1 downregulation and activates Nrf2 target gene transcription. • PA-induced Keap1 degradation is partly mediated by the autophagic pathway. • PA-induced Keap1 degradation depends on p62. • Ablation of p62 exacerbates PA-mediated apoptotic cell death.

Pseudomonas putida response in membrane bioreactors under salicylic acid-induced stress conditions

Energy Technology Data Exchange (ETDEWEB)

Collado, Sergio; Rosas, Irene; González, Elena; Gutierrez-Lavin, Antonio; Diaz, Mario, E-mail: mariodiaz@uniovi.es

2014-02-01

Highlights: • MBR under feed-induced stress conditions: starvation and changing feeding conditions. • High capacity of MBR to withstand high variations in feed loads. • Slow biofilm formation under starvation conditions during the first days. • Observed growth of P. putida for substrate to microorganism ratio higher than 0.6 g/g. • Maximum specific growth rate and growth yield values of around 37.5 h{sup −1} and 0.5 g/g. - Abstract: Starvation and changing feeding conditions are frequently characteristics of wastewater treatment plants. They are typical causes of unsteady-state operation of biological systems and provoke cellular stress. The response of a membrane bioreactor functioning under feed-induced stress conditions is studied here. In order to simplify and considerably amplify the response to stress and to obtain a reference model, a pure culture of Pseudomonas putida was selected instead of an activated sludge and a sole substrate (salicylic acid) was employed. The system degraded salicylic acid at 100–1100 mg/L with a high level of efficiency, showed rapid acclimation without substrate or product inhibition phenomena and good stability in response to unsteady states caused by feed variations. Under starvation conditions, specific degradation rates of around 15 mg/g h were achieved during the adaptation of the biomass to the new conditions and no biofilm formation was observed during the first days of experimentation using an initial substrate to microorganisms ratio lower than 0.1. When substrate was added to the reactor as pulses resulting in rapidly changing concentrations, P. putida growth was observed only for substrate to microorganism ratios higher than 0.6, with a maximum Y{sub X/S} of 0.5 g/g. Biofilm development under changing feeding conditions was fast, biomass detachment only being significant for biomass concentrations on the membrane surface that were higher than 16 g/m{sup 2}.

Pseudomonas putida response in membrane bioreactors under salicylic acid-induced stress conditions

International Nuclear Information System (INIS)

Collado, Sergio; Rosas, Irene; González, Elena; Gutierrez-Lavin, Antonio; Diaz, Mario

2014-01-01

Highlights: • MBR under feed-induced stress conditions: starvation and changing feeding conditions. • High capacity of MBR to withstand high variations in feed loads. • Slow biofilm formation under starvation conditions during the first days. • Observed growth of P. putida for substrate to microorganism ratio higher than 0.6 g/g. • Maximum specific growth rate and growth yield values of around 37.5 h −1 and 0.5 g/g. - Abstract: Starvation and changing feeding conditions are frequently characteristics of wastewater treatment plants. They are typical causes of unsteady-state operation of biological systems and provoke cellular stress. The response of a membrane bioreactor functioning under feed-induced stress conditions is studied here. In order to simplify and considerably amplify the response to stress and to obtain a reference model, a pure culture of Pseudomonas putida was selected instead of an activated sludge and a sole substrate (salicylic acid) was employed. The system degraded salicylic acid at 100–1100 mg/L with a high level of efficiency, showed rapid acclimation without substrate or product inhibition phenomena and good stability in response to unsteady states caused by feed variations. Under starvation conditions, specific degradation rates of around 15 mg/g h were achieved during the adaptation of the biomass to the new conditions and no biofilm formation was observed during the first days of experimentation using an initial substrate to microorganisms ratio lower than 0.1. When substrate was added to the reactor as pulses resulting in rapidly changing concentrations, P. putida growth was observed only for substrate to microorganism ratios higher than 0.6, with a maximum Y X/S of 0.5 g/g. Biofilm development under changing feeding conditions was fast, biomass detachment only being significant for biomass concentrations on the membrane surface that were higher than 16 g/m 2

Alterations in cellular metabolism modulate CD1d-mediated NKT-cell responses.

Science.gov (United States)

Webb, Tonya J; Carey, Gregory B; East, James E; Sun, Wenji; Bollino, Dominique R; Kimball, Amy S; Brutkiewicz, Randy R

2016-08-01

Natural killer T (NKT) cells play a critical role in the host's innate immune response. CD1d-mediated presentation of glycolipid antigens to NKT cells has been established; however, the mechanisms by which NKT cells recognize infected or cancerous cells remain unclear. 5(')-AMP activated protein kinase (AMPK) is a master regulator of lipogenic pathways. We hypothesized that activation of AMPK during infection and malignancy could alter the repertoire of antigens presented by CD1d and serve as a danger signal to NKT cells. In this study, we examined the effect of alterations in metabolism on CD1d-mediated antigen presentation to NKT cells and found that an infection with lymphocytic choriomeningitis virus rapidly increased CD1d-mediated antigen presentation. Hypoxia inducible factors (HIF) enhance T-cell effector functions during infection, therefore antigen presenting cells pretreated with pharmacological agents that inhibit glycolysis, induce HIF and activate AMPK were assessed for their ability to induce NKT-cell responses. Pretreatment with 2-deoxyglucose, cobalt chloride, AICAR and metformin significantly enhanced CD1d-mediated NKT-cell activation. In addition, NKT cells preferentially respond to malignant B cells and B-cell lymphomas express HIF-1α. These data suggest that targeting cellular metabolism may serve as a novel means of inducing innate immune responses. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Silibinin induces mitochondrial NOX4-mediated endoplasmic reticulum stress response and its subsequent apoptosis

International Nuclear Information System (INIS)

Kim, Sang-Hun; Kim, Kwang-Youn; Yu, Sun-Nyoung; Seo, Young-Kyo; Chun, Sung-Sik; Yu, Hak-Sun; Ahn, Soon-Cheol

2016-01-01

Silibinin, a biologically active compound of milk thistle, has chemopreventive effects on cancer cell lines. Recently it was reported that silibinin inhibited tumor growth through activation of the apoptotic signaling pathway. Although various evidences showed multiple signaling pathways of silibinin in apoptosis, there were no reports to address the clear mechanism of ROS-mediated pathway in prostate cancer PC-3 cells. Several studies suggested that reactive oxygen species (ROS) play an important role in various signaling cascades, but the primary source of ROS was currently unclear. The effect of silibinin was investigated on cell growth of prostate cell lines by MTT assay. We examined whether silibinin induced apoptosis through production of ROS using flow cytometry. Expression of apoptosis-, endoplasmic reticulum (ER)-related protein and gene were determined by western blotting and RT-PCR, respectively. Results showed that silibinin triggered mitochondrial ROS production through NOX4 expression and finally led to induce apoptosis. In addition, mitochondrial ROS caused ER stress through disruption of Ca 2+ homeostasis. Co-treatment of ROS inhibitor reduced the silibinin-induced apoptosis through the inhibition of NOX4 expression, resulting in reduction of both Ca 2+ level and ER stress response. Taken together, silibinin induced mitochondrial ROS-dependent apoptosis through NOX4, which is associated with disruption of Ca 2+ homeostasis and ER stress response. Therefore, the regulation of NOX4, mitochondrial ROS producer, could be a potential target for the treatment of prostate cancer. The online version of this article (doi:10.1186/s12885-016-2516-6) contains supplementary material, which is available to authorized users

Chk2 mediates RITA-induced apoptosis.

Science.gov (United States)

de Lange, J; Verlaan-de Vries, M; Teunisse, A F A S; Jochemsen, A G

2012-06-01

Reactivation of the p53 tumor-suppressor protein by small molecules like Nutlin-3 and RITA (reactivation of p53 and induction of tumor cell apoptosis) is a promising strategy for cancer therapy. The molecular mechanisms involved in the responses to RITA remain enigmatic. Several groups reported the induction of a p53-dependent DNA damage response. Furthermore, the existence of a p53-dependent S-phase checkpoint has been suggested, involving the checkpoint kinase Chk1. We have recently shown synergistic induction of apoptosis by RITA in combination with Nutlin-3, and we observed concomitant Chk2 phosphorylation. Therefore, we investigated whether Chk2 contributes to the cellular responses to RITA. Strikingly, the induction of apoptosis seemed entirely Chk2 dependent. Transcriptional activity of p53 in response to RITA required the presence of Chk2. A partial rescue of apoptosis observed in Noxa knockdown cells emphasized the relevance of p53 transcriptional activity for RITA-induced apoptosis. In addition, we observed an early p53- and Chk2-dependent block of DNA replication upon RITA treatment. Replicating cells seemed more prone to entering RITA-induced apoptosis. Furthermore, the RITA-induced DNA damage response, which was not a secondary effect of apoptosis induction, was strongly attenuated in cells lacking p53 or Chk2. In conclusion, we identified Chk2 as an essential mediator of the cellular responses to RITA.

Botulinum neurotoxin type A induces TLR2-mediated inflammatory responses in macrophages.

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Yun Jeong Kim

Full Text Available Botulinum neurotoxin type A (BoNT/A is the most potent protein toxin and causes fatal flaccid muscle paralysis by blocking neurotransmission. Application of BoNT/A has been extended to the fields of therapeutics and biodefense. Nevertheless, the global response of host immune cells to authentic BoNT/A has not been reported. Employing microarray analysis, we performed global transcriptional profiling of RAW264.7 cells, a murine alveolar macrophage cell line. We identified 70 genes that were modulated following 1 nM BoNT/A treatment. The altered genes were mainly involved in signal transduction, immunity and defense, protein metabolism and modification, neuronal activities, intracellular protein trafficking, and muscle contraction. Microarray data were validated with real-time RT-PCR for seven selected genes including tlr2, tnf, inos, ccl4, slpi, stx11, and irg1. Proinflammatory mediators such as nitric oxide (NO and tumor necrosis factor alpha (TNFα were induced in a dose-dependent manner in BoNT/A-stimulated RAW264.7 cells. Increased expression of these factors was inhibited by monoclonal anti-Toll-like receptor 2 (TLR2 and inhibitors specific to intracellular proteins such as c-Jun N-terminal kinase (JNK, extracellular signal-regulated kinase (ERK, and p38 mitogen-activated protein kinase (MAPK. BoNT/A also suppressed lipopolysaccharide-induced NO and TNFα production from RAW264.7 macrophages at the transcription level by blocking activation of JNK, ERK, and p38 MAPK. As confirmed by TLR2-/- knock out experiments, these results suggest that BoNT/A induces global gene expression changes in host immune cells and that host responses to BoNT/A proceed through a TLR2-dependent pathway, which is modulated by JNK, ERK, and p38 MAPK.

The Arabidopsis Mediator Complex Subunits MED16, MED14, and MED2 Regulate Mediator and RNA Polymerase II Recruitment to CBF-Responsive Cold-Regulated Genes[C][W][OPEN

Science.gov (United States)

Hemsley, Piers A.; Hurst, Charlotte H.; Kaliyadasa, Ewon; Lamb, Rebecca; Knight, Marc R.; De Cothi, Elizabeth A.; Steele, John F.; Knight, Heather

2014-01-01

The Mediator16 (MED16; formerly termed SENSITIVE TO FREEZING6 [SFR6]) subunit of the plant Mediator transcriptional coactivator complex regulates cold-responsive gene expression in Arabidopsis thaliana, acting downstream of the C-repeat binding factor (CBF) transcription factors to recruit the core Mediator complex to cold-regulated genes. Here, we use loss-of-function mutants to show that RNA polymerase II recruitment to CBF-responsive cold-regulated genes requires MED16, MED2, and MED14 subunits. Transcription of genes known to be regulated via CBFs binding to the C-repeat motif/drought-responsive element promoter motif requires all three Mediator subunits, as does cold acclimation–induced freezing tolerance. In addition, these three subunits are required for low temperature–induced expression of some other, but not all, cold-responsive genes, including genes that are not known targets of CBFs. Genes inducible by darkness also required MED16 but required a different combination of Mediator subunits for their expression than the genes induced by cold. Together, our data illustrate that plants control transcription of specific genes through the action of subsets of Mediator subunits; the specific combination defined by the nature of the stimulus but also by the identity of the gene induced. PMID:24415770

Ferulic Acid Induces Th1 Responses by Modulating the Function of Dendritic Cells and Ameliorates Th2-Mediated Allergic Airway Inflammation in Mice

Directory of Open Access Journals (Sweden)

Chen-Chen Lee

2015-01-01

Full Text Available This study investigated the immunomodulatory effects of ferulic acid (FA on antigen-presenting dendritic cells (DCs in vitro and its antiallergic effects against ovalbumin- (OVA- induced Th2-mediated allergic asthma in mice. The activation of FA-treated bone marrow-derived DCs by lipopolysaccharide (LPS stimulation induced a high level of interleukin- (IL- 12 but reduced the expression levels of the proinflammatory cytokines IL-1β, IL-6, and tumor necrosis factor- (TNF- α. Compared to control-treated DCs, FA significantly enhanced the expressions of Notch ligand Delta-like 4 (Dll4, MHC class II, and CD40 molecules by these DCs. Furthermore, these FA-treated DCs enhanced T-cell proliferation and Th1 cell polarization. In animal experiments, oral administration of FA reduced the levels of OVA-specific immunoglobulin E (IgE and IgG1 and enhanced IgG2a antibody production in serum. It also ameliorated airway hyperresponsiveness and attenuated eosinophilic pulmonary infiltration in dose-dependent manners. In addition, FA treatment inhibited the production of eotaxin, Th2 cytokines (IL-4, IL-5, and IL-13, and proinflammatory cytokines but promoted the Th1 cytokine interferon- (IFN- γ production in bronchoalveolar lavage fluid (BALF and the culture supernatant of spleen cells. These findings suggest that FA exhibits an antiallergic effect via restoring Th1/Th2 imbalance by modulating DCs function in an asthmatic mouse model.

Fatty Acids, Lipid Mediators, and T-Cell Function

Science.gov (United States)

de Jong, Anja J.; Kloppenburg, Margreet; Toes, René E. M.; Ioan-Facsinay, Andreea

2014-01-01

Research toward the mechanisms underlying obesity-linked complications has intensified during the last years. As a consequence, it has become clear that metabolism and immunity are intimately linked. Free fatty acids and other lipids acquired in excess by current feeding patterns have been proposed to mediate this link due to their immune modulatory capacity. The functional differences between saturated and unsaturated fatty acids, in combination with their dietary intake are believed to modulate the outcome of immune responses. Moreover, unsaturated fatty acids can be oxidized in a tightly regulated and specific manner to generate either potent pro-inflammatory or pro-resolving lipid mediators. These oxidative derivatives of fatty acids have received detailed attention during the last years, as they have proven to have strong immune modulatory capacity, even in pM ranges. Both fatty acids and oxidized fatty acids have been studied especially in relation to macrophage and T-cells functions. In this review, we propose to focus on the effect of fatty acids and their oxidative derivatives on T-cells, as it is an active area of research during the past 5 years. The effect of fatty acids and their derivatives on activation and proliferation of T-cells, as well as the delicate balance between stimulation and lipotoxicity will be discussed. Moreover, the receptors involved in the interaction between free fatty acids and their derivatives with T-cells will be summarized. Finally, the mechanisms involved in modulation of T-cells by fatty acids will be addressed, including cellular signaling and metabolism of T-cells. The in vitro results will be placed in context of in vivo studies both in humans and mice. In this review, we summarize the latest findings on the immune modulatory function of lipids on T-cells and will point out novel directions for future research. PMID:25352844

Transcriptional profile of sweet orange in response to chitosan and salicylic acid.

Science.gov (United States)

Coqueiro, Danila Souza Oliveira; de Souza, Alessandra Alves; Takita, Marco Aurélio; Rodrigues, Carolina Munari; Kishi, Luciano Takeshi; Machado, Marcos Antonio

2015-04-12

Resistance inducers have been used in annual crops as an alternative for disease control. Wood perennial fruit trees, such as those of the citrus species, are candidates for treatment with resistance inducers, such as salicylic acid (SA) and chitosan (CHI). However, the involved mechanisms in resistance induced by elicitors in citrus are currently few known. In the present manuscript, we report information regarding the transcriptional changes observed in sweet orange in response to exogenous applications of SA and CHI using RNA-seq technology. More genes were induced by SA treatment than by CHI treatment. In total, 1,425 differentially expressed genes (DEGs) were identified following treatment with SA, including the important genes WRKY50, PR2, and PR9, which are known to participate in the salicylic acid signaling pathway, and genes involved in ethylene/Jasmonic acid biosynthesis (ACS12, AP2 domain-containing transcription factor, and OPR3). In addition, SA treatment promoted the induction of a subset of genes involved in several metabolic processes, such as redox states and secondary metabolism, which are associated with biotic stress. For CHI treatment, there were 640 DEGs, many of them involved in secondary metabolism. For both SA and CHI treatments, the auxin pathway genes were repressed, but SA treatment promoted induction in the ethylene and jasmonate acid pathway genes, in addition to repressing the abscisic acid pathway genes. Chitosan treatment altered some hormone metabolism pathways. The DEGs were validated by quantitative Real-Time PCR (qRT-PCR), and the results were consistent with the RNA-seq data, with a high correlation between the two analyses. We expanded the available information regarding induced defense by elicitors in a species of Citrus that is susceptible to various diseases and identified the molecular mechanisms by which this defense might be mediated.

Ghrelin mediates stress-induced food-reward behavior in mice.

Science.gov (United States)

Chuang, Jen-Chieh; Perello, Mario; Sakata, Ichiro; Osborne-Lawrence, Sherri; Savitt, Joseph M; Lutter, Michael; Zigman, Jeffrey M

2011-07-01

The popular media and personal anecdotes are rich with examples of stress-induced eating of calorically dense "comfort foods." Such behavioral reactions likely contribute to the increased prevalence of obesity in humans experiencing chronic stress or atypical depression. However, the molecular substrates and neurocircuits controlling the complex behaviors responsible for stress-based eating remain mostly unknown, and few animal models have been described for probing the mechanisms orchestrating this response. Here, we describe a system in which food-reward behavior, assessed using a conditioned place preference (CPP) task, is monitored in mice after exposure to chronic social defeat stress (CSDS), a model of prolonged psychosocial stress, featuring aspects of major depression and posttraumatic stress disorder. Under this regime, CSDS increased both CPP for and intake of high-fat diet, and stress-induced food-reward behavior was dependent on signaling by the peptide hormone ghrelin. Also, signaling specifically in catecholaminergic neurons mediated not only ghrelin's orexigenic, antidepressant-like, and food-reward behavioral effects, but also was sufficient to mediate stress-induced food-reward behavior. Thus, this mouse model has allowed us to ascribe a role for ghrelin-engaged catecholaminergic neurons in stress-induced eating.

Global protein phosphorylation dynamics during deoxynivalenol-induced ribotoxic stress response in the macrophage

Energy Technology Data Exchange (ETDEWEB)

Pan, Xiao [Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824 (United States); Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824 (United States); Whitten, Douglas A. [Research Technology Support Facility, Proteomics Core, Michigan State University, East Lansing, MI 48824 (United States); Wu, Ming [Department of Computer Science and Engineering, Michigan State University, East Lansing, MI 48824 (United States); Chan, Christina [Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824 (United States); Department of Computer Science and Engineering, Michigan State University, East Lansing, MI 48824 (United States); Wilkerson, Curtis G. [Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824 (United States); Research Technology Support Facility, Proteomics Core, Michigan State University, East Lansing, MI 48824 (United States); Pestka, James J., E-mail: pestka@msu.edu [Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824 (United States); Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824 (United States); Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824 (United States)

2013-04-15

Deoxynivalenol (DON), a trichothecene mycotoxin produced by Fusarium that commonly contaminates food, is capable of activating mononuclear phagocytes of the innate immune system via a process termed the ribotoxic stress response (RSR). To encapture global signaling events mediating RSR, we quantified the early temporal (≤ 30 min) phosphoproteome changes that occurred in RAW 264.7 murine macrophage during exposure to a toxicologically relevant concentration of DON (250 ng/mL). Large-scale phosphoproteomic analysis employing stable isotope labeling of amino acids in cell culture (SILAC) in conjunction with titanium dioxide chromatography revealed that DON significantly upregulated or downregulated phosphorylation of 188 proteins at both known and yet-to-be functionally characterized phosphosites. DON-induced RSR is extremely complex and goes far beyond its prior known capacity to inhibit translation and activate MAPKs. Transcriptional regulation was the main target during early DON-induced RSR, covering over 20% of the altered phosphoproteins as indicated by Gene Ontology annotation and including transcription factors/cofactors and epigenetic modulators. Other biological processes impacted included cell cycle, RNA processing, translation, ribosome biogenesis, monocyte differentiation and cytoskeleton organization. Some of these processes could be mediated by signaling networks involving MAPK-, NFκB-, AKT- and AMPK-linked pathways. Fuzzy c-means clustering revealed that DON-regulated phosphosites could be discretely classified with regard to the kinetics of phosphorylation/dephosphorylation. The cellular response networks identified provide a template for further exploration of the mechanisms of trichothecenemycotoxins and other ribotoxins, and ultimately, could contribute to improved mechanism-based human health risk assessment. - Highlights: ► Mycotoxin deoxynivalenol (DON) induces immunotoxicity via ribotoxic stress response. ► SILAC phosphoproteomics using

Global protein phosphorylation dynamics during deoxynivalenol-induced ribotoxic stress response in the macrophage

International Nuclear Information System (INIS)

Pan, Xiao; Whitten, Douglas A.; Wu, Ming; Chan, Christina; Wilkerson, Curtis G.; Pestka, James J.

2013-01-01

Deoxynivalenol (DON), a trichothecene mycotoxin produced by Fusarium that commonly contaminates food, is capable of activating mononuclear phagocytes of the innate immune system via a process termed the ribotoxic stress response (RSR). To encapture global signaling events mediating RSR, we quantified the early temporal (≤ 30 min) phosphoproteome changes that occurred in RAW 264.7 murine macrophage during exposure to a toxicologically relevant concentration of DON (250 ng/mL). Large-scale phosphoproteomic analysis employing stable isotope labeling of amino acids in cell culture (SILAC) in conjunction with titanium dioxide chromatography revealed that DON significantly upregulated or downregulated phosphorylation of 188 proteins at both known and yet-to-be functionally characterized phosphosites. DON-induced RSR is extremely complex and goes far beyond its prior known capacity to inhibit translation and activate MAPKs. Transcriptional regulation was the main target during early DON-induced RSR, covering over 20% of the altered phosphoproteins as indicated by Gene Ontology annotation and including transcription factors/cofactors and epigenetic modulators. Other biological processes impacted included cell cycle, RNA processing, translation, ribosome biogenesis, monocyte differentiation and cytoskeleton organization. Some of these processes could be mediated by signaling networks involving MAPK-, NFκB-, AKT- and AMPK-linked pathways. Fuzzy c-means clustering revealed that DON-regulated phosphosites could be discretely classified with regard to the kinetics of phosphorylation/dephosphorylation. The cellular response networks identified provide a template for further exploration of the mechanisms of trichothecenemycotoxins and other ribotoxins, and ultimately, could contribute to improved mechanism-based human health risk assessment. - Highlights: ► Mycotoxin deoxynivalenol (DON) induces immunotoxicity via ribotoxic stress response. ► SILAC phosphoproteomics using

Cultured hypothalamic neurons are resistant to inflammation and insulin resistance induced by saturated fatty acids.

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Choi, Sun Ju; Kim, Francis; Schwartz, Michael W; Wisse, Brent E

2010-06-01

Hypothalamic inflammation induced by high-fat feeding causes insulin and leptin resistance and contributes to the pathogenesis of obesity. Since in vitro exposure to saturated fatty acids causes inflammation and insulin resistance in many cultured cell types, we determined how cultured hypothalamic neurons respond to this stimulus. Two murine hypothalamic neuronal cell cultures, N43/5 and GT1-7, were exposed to escalating concentrations of saturated fatty acids for up to 24 h. Harvested cells were evaluated for activation of inflammation by gene expression and protein content. Insulin-treated cells were evaluated for induction of markers of insulin receptor signaling (p-IRS, p-Akt). In both hypothalamic cell lines, inflammation was induced by prototypical inflammatory mediators LPS and TNFalpha, as judged by induction of IkappaBalpha (3- to 5-fold) and IL-6 (3- to 7-fold) mRNA and p-IkappaBalpha protein, and TNFalpha pretreatment reduced insulin-mediated p-Akt activation by 30% (P fatty acid (100, 250, or 500 microM for neurons, whereas they did in control muscle and endothelial cell lines. Despite the lack of evidence of inflammatory signaling, saturated fatty acid exposure in cultured hypothalamic neurons causes endoplasmic reticulum stress, induces mitogen-activated protein kinase, and causes apoptotic cell death with prolonged exposure. We conclude that saturated fatty acid exposure does not induce inflammatory signaling or insulin resistance in cultured hypothalamic neurons. Therefore, hypothalamic neuronal inflammation in the setting of DIO may involve an indirect mechanism mediated by saturated fatty acids on nonneuronal cells.

Palmitic Acid Induces Osteoblastic Differentiation in Vascular Smooth Muscle Cells through ACSL3 and NF-κB, Novel Targets of Eicosapentaenoic Acid

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Kageyama, Aiko; Matsui, Hiroki; Ohta, Masahiko; Sambuichi, Keisuke; Kawano, Hiroyuki; Notsu, Tatsuto; Imada, Kazunori; Yokoyama, Tomoyuki; Kurabayashi, Masahiko

2013-01-01

Free fatty acids (FFAs), elevated in metabolic syndrome and diabetes, play a crucial role in the development of atherosclerotic cardiovascular disease, and eicosapentaenoic acid (EPA) counteracts many aspects of FFA-induced vascular pathology. Although vascular calcification is invariably associated with atherosclerosis, the mechanisms involved are not completely elucidated. In this study, we tested the hypothesis that EPA prevents the osteoblastic differentiation and mineralization of vascular smooth muscle cells (VSMC) induced by palmitic acid (PA), the most abundant long-chain saturated fatty acid in plasma. PA increased and EPA abolished the expression of the genes for bone-related proteins, including bone morphogenetic protein (BMP)-2, Msx2 and osteopontin in human aortic smooth muscle cells (HASMC). Among the long-chain acyl-CoA synthetase (ACSL) subfamily, ACSL3 expression was predominant in HASMC, and PA robustly increased and EPA efficiently inhibited ACSL3 expression. Importantly, PA-induced osteoblastic differentiation was mediated, at least in part, by ACSL3 activation because acyl-CoA synthetase (ACS) inhibitor or siRNA targeted to ACSL3 completely prevented the PA induction of both BMP-2 and Msx2. Conversely, adenovirus-mediated ACSL3 overexpression enhanced PA-induced BMP-2 and Msx2 expression. In addition, EPA, ACSL3 siRNA and ACS inhibitor attenuated calcium deposition and caspase activation induced by PA. Notably, PA induced activation of NF-κB, and NF-κB inhibitor prevented PA-induction of osteoblastic gene expression and calcium deposition. Immunohistochemistry revealed the prominent expression of ACSL3 in VSMC and macrophages in human non-calcifying and calcifying atherosclerotic plaques from the carotid arteries. These results identify ACSL3 and NF-κB as mediators of PA-induced osteoblastic differentiation and calcium deposition in VSMC and suggest that EPA prevents vascular calcification by inhibiting such a new molecular pathway elicited

Valproate induced hepatic steatosis by enhanced fatty acid uptake and triglyceride synthesis.

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Bai, Xupeng; Hong, Weipeng; Cai, Peiheng; Chen, Yibei; Xu, Chuncao; Cao, Di; Yu, Weibang; Zhao, Zhongxiang; Huang, Min; Jin, Jing

2017-06-01

Steatosis is the characteristic type of VPA-induced hepatotoxicity and may result in life-threatening hepatic lesion. Approximately 61% of patients treated with VPA have been diagnosed with hepatic steatosis through ultrasound examination. However, the mechanisms underlying VPA-induced intracellular fat accumulation are not yet fully understood. Here we demonstrated the involvement of fatty acid uptake and lipogenesis in VPA-induced hepatic steatosis in vitro and in vivo by using quantitative real-time PCR (qRT-PCR) analysis, western blotting analysis, fatty acid uptake assays, Nile Red staining assays, and Oil Red O staining assays. Specifically, we found that the expression of cluster of differentiation 36 (CD36), an important fatty acid transport, and diacylglycerol acyltransferase 2 (DGAT2) were significantly up-regulated in HepG2 cells and livers of C57B/6J mice after treatment with VPA. Furthermore, VPA treatment remarkably enhanced the efficiency of fatty acid uptake mediated by CD36, while this effect was abolished by the interference with CD36-specific siRNA. Also, VPA treatment significantly increased DGAT2 expression as a result of the inhibition of mitogen-activated protein kinase kinase (MEK) - extracellular regulated kinase (ERK) pathway; however, DGAT2 knockdown significantly alleviated VPA-induced intracellular lipid accumulation. Additionally, we also found that sterol regulatory element binding protein-1c (SREBP-1c)-mediated fatty acid synthesis may be not involved in VPA-induced hepatic steatosis. Overall, VPA-triggered over-regulation of CD36 and DGAT2 could be helpful for a better understanding of the mechanisms underlying VPA-induced hepatic steatosis and may offer novel therapeutic strategies to combat VPA-induced hepatotoxicity. Copyright © 2017 Elsevier Inc. All rights reserved.

Role of abscisic acid in strigolactone-induced salt stress tolerance in arbuscular mycorrhizal Sesbania cannabina seedlings.

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Ren, Cheng-Gang; Kong, Cun-Cui; Xie, Zhi-Hong

2018-05-03

Strigolactones (SLs) are considered to be a novel class of phytohormone involved in plant defense responses. Currently, their relationships with other plant hormones, such as abscisic acid (ABA), during responses to salinity stress are largely unknown. In this study, the relationship between SL and ABA during the induction of H 2 O 2 - mediated tolerance to salt stress were studied in arbuscular mycorrhizal (AM) Sesbania cannabina seedlings. The SL levels increased after ABA treatments and decreased when ABA biosynthesis was inhibited in AM plants. Additionally, the expression levels of SL-biosynthesis genes in AM plants increased following treatments with exogenous ABA and H 2 O 2 . Furthermore, ABA-induced SL production was blocked by a pre-treatment with dimethylthiourea, which scavenges H 2 O 2 . In contrast, ABA production was unaffected by dimethylthiourea. Abscisic acid induced only partial and transient increases in the salt tolerance of TIS108 (a SL synthesis inhibitor) treated AM plants, whereas SL induced considerable and prolonged increases in salt tolerance after a pre-treatment with tungstate. These results strongly suggest that ABA is regulating the induction of salt tolerance by SL in AM S. cannabina seedlings.

A fluorescence-coupled assay for gamma aminobutyric acid (GABA reveals metabolic stress-induced modulation of GABA content in neuroendocrine cancer.

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Joseph E Ippolito

Full Text Available Pathways involved in the synthesis of the neurotransmitter gamma-aminobutyric acid (GABA have been implicated in the pathogenesis of high grade neuroendocrine (NE neoplasms as well as neoplasms from a non-NE lineage. Using The Cancer Genome Atlas, overexpression of the GABA synthetic enzyme, glutamate decarboxylase 1 (GAD1, was found to be associated with decreased disease free-survival in prostate adenocarcinoma and decreased overall survival in clear cell renal cell carcinomas. Furthermore, GAD1 was found to be expressed in castrate-resistant prostate cancer cell lines, but not androgen-responsive cell lines. Using a novel fluorescence-coupled enzymatic microplate assay for GABA mediated through reduction of resazurin in a prostate neuroendocrine carcinoma (PNEC cell line, acid microenvironment-induced stress increased GABA levels while alkaline microenvironment-induced stress decreased GABA through modulation of GAD1 and glutamine synthetase (GLUL activities. Moreover, glutamine but not glucose deprivation decreased GABA through modulation of GLUL. Consistent with evidence in prokaryotic and eukaryotic organisms that GABA synthesis mediated through GAD1 may play a crucial role in surviving stress, GABA may be an important mediator of stress survival in neoplasms. These findings identify GABA synthesis and metabolism as a potentially important pathway for regulating cancer cell stress response as well as a potential target for therapeutic strategies.

Fiber-Mediated Nourishment of Gut Microbiota Protects against Diet-Induced Obesity by Restoring IL-22-Mediated Colonic Health.

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Zou, Jun; Chassaing, Benoit; Singh, Vishal; Pellizzon, Michael; Ricci, Matthew; Fythe, Michael D; Kumar, Matam Vijay; Gewirtz, Andrew T

2018-01-10

Dietary supplementation with fermentable fiber suppresses adiposity and the associated parameters of metabolic syndrome. Microbiota-generated fiber-derived short-chain fatty acids (SCFAs) and free fatty acid receptors including GPR43 are thought to mediate these effects. We find that while fermentable (inulin), but not insoluble (cellulose), fiber markedly protected mice against high-fat diet (HFD)-induced metabolic syndrome, the effect was not significantly impaired by either inhibiting SCFA production or genetic ablation of GPR43. Rather, HFD decimates gut microbiota, resulting in loss of enterocyte proliferation, leading to microbiota encroachment, low-grade inflammation (LGI), and metabolic syndrome. Enriching HFD with inulin restored microbiota loads, interleukin-22 (IL-22) production, enterocyte proliferation, and antimicrobial gene expression in a microbiota-dependent manner, as assessed by antibiotic and germ-free approaches. Inulin-induced IL-22 expression, which required innate lymphoid cells, prevented microbiota encroachment and protected against LGI and metabolic syndrome. Thus, fermentable fiber protects against metabolic syndrome by nourishing microbiota to restore IL-22-mediated enterocyte function. Copyright © 2017 Elsevier Inc. All rights reserved.

Maresin 1, a Proresolving Lipid Mediator, Mitigates Carbon Tetrachloride-Induced Liver Injury in Mice

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Ruidong Li

2016-01-01

Full Text Available Maresin 1 (MaR 1 was recently reported to have protective properties in several different animal models of acute inflammation by inhibiting inflammatory response. However, its function in acute liver injury is still unknown. To address this question, we induced liver injury in BALB/c mice with intraperitoneal injection of carbon tetrachloride with or without treatment of MaR 1. Our data showed that MaR 1 attenuated hepatic injury, oxidative stress, and lipid peroxidation induced by carbon tetrachloride, as evidenced by increased thiobarbituric acid reactive substances and reactive oxygen species levels were inhibited by treatment of MaR 1. Furthermore, MaR 1 increased activities of antioxidative mediators in carbon tetrachloride-treated mice liver. MaR 1 decreased indices of inflammatory mediators such as tumor necrosis factor-α, interleukin-6, interleukin-1β, monocyte chemotactic protein 1, myeloperoxidase, cyclooxygenase-2, and inducible nitric oxide synthase. Administration of MaR 1 inhibited activation of nuclear factor kappa B (NF-κb and mitogen-activated protein kinases (MAPKs in the liver of CCl4 treated mice. In conclusion, these results suggested the antioxidative, anti-inflammatory properties of MaR 1 in CCl4 induced liver injury. The possible mechanism is partly implicated in its abilities to inhibit ROS generation and activation of NF-κb and MAPK pathway.

Paeoniflorin protects against ischemia-induced brain damages in rats via inhibiting MAPKs/NF-κB-mediated inflammatory responses.

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Ruo-Bing Guo

Full Text Available Paeoniflorin (PF, the principal component of Paeoniae Radix prescribed in traditional Chinese medicine, has been reported to exhibit many pharmacological effects including protection against ischemic injury. However, the mechanisms underlying the protective effects of PF on cerebral ischemia are still under investigation. The present study showed that PF treatment for 14 days could significantly inhibit transient middle cerebral artery occlusion (MCAO-induced over-activation of astrocytes and microglia, and prevented up-regulations of pro-inflamamtory mediators (TNFα, IL-1β, iNOS, COX(2 and 5-LOX in plasma and brain. Further study demonstrated that chronic treatment with PF suppressed the activations of JNK and p38 MAPK, but enhanced ERK activation. And PF could reverse ischemia-induced activation of NF-κB signaling pathway. Moreover, our in vitro study revealed that PF treatment protected against TNFα-induced cell apoptosis and neuronal loss. Taken together, the present study demonstrates that PF produces a delayed protection in the ischemia-injured rats via inhibiting MAPKs/NF-κB mediated peripheral and cerebral inflammatory response. Our study reveals that PF might be a potential neuroprotective agent for stroke.

Paeoniflorin protects against ischemia-induced brain damages in rats via inhibiting MAPKs/NF-κB-mediated inflammatory responses.

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Guo, Ruo-Bing; Wang, Guo-Feng; Zhao, An-Peng; Gu, Jun; Sun, Xiu-Lan; Hu, Gang

2012-01-01

Paeoniflorin (PF), the principal component of Paeoniae Radix prescribed in traditional Chinese medicine, has been reported to exhibit many pharmacological effects including protection against ischemic injury. However, the mechanisms underlying the protective effects of PF on cerebral ischemia are still under investigation. The present study showed that PF treatment for 14 days could significantly inhibit transient middle cerebral artery occlusion (MCAO)-induced over-activation of astrocytes and microglia, and prevented up-regulations of pro-inflamamtory mediators (TNFα, IL-1β, iNOS, COX(2) and 5-LOX) in plasma and brain. Further study demonstrated that chronic treatment with PF suppressed the activations of JNK and p38 MAPK, but enhanced ERK activation. And PF could reverse ischemia-induced activation of NF-κB signaling pathway. Moreover, our in vitro study revealed that PF treatment protected against TNFα-induced cell apoptosis and neuronal loss. Taken together, the present study demonstrates that PF produces a delayed protection in the ischemia-injured rats via inhibiting MAPKs/NF-κB mediated peripheral and cerebral inflammatory response. Our study reveals that PF might be a potential neuroprotective agent for stroke.

Induction of intestinal pro-inflammatory immune responses by lipoteichoic acid

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Zadeh Mojgan

2012-03-01

Full Text Available Abstract Background The cellular and molecular mechanisms of inflammatory bowel disease are not fully understood; however, data indicate that uncontrolled chronic inflammation induced by bacterial gene products, including lipoteichoic acid (LTA, may trigger colonic inflammation resulting in disease pathogenesis. LTA is a constituent glycolipid of Gram-positive bacteria that shares many inflammatory properties with lipopolysaccharide and plays a critical role in the pathogenesis of severe inflammatory responses via Toll-like receptor 2. Accordingly, we elucidate the role of LTA in immune stimulation and induced colitis in vivo. Methods To better understand the molecular mechanisms utilized by the intestinal microbiota and their gene products to induce or subvert inflammation, specifically the effect(s of altered surface layer protein expression on the LTA-mediated pro-inflammatory response, the Lactobacillus acidophilus surface layer protein (Slp genes encoding SlpB and SlpX were deleted resulting in a SlpB- and SlpX- mutant that continued to express SlpA (assigned as NCK2031. Results Our data show profound activation of dendritic cells by NCK2031, wild-type L. acidophilus (NCK56, and purified Staphylococcus aureus-LTA. In contrary to the LTA-deficient strain NCK2025, the LTA-expressing strains NCK2031 and NCK56, as well as S. aureus-LTA, induce pro-inflammatory innate and T cell immune responses in vivo. Additionally, neither NCK2031 nor S. aureus-LTA supplemented in drinking water protected mice from DSS-colitis, but instead, induced significant intestinal inflammation resulting in severe colitis and tissue destruction. Conclusions These findings suggest that directed alteration of two of the L. acidophilus NCFM-Slps did not ameliorate LTA-induced pro-inflammatory signals and subsequent colitis.

Muscle-derived expression of the chemokine CXCL1 attenuates diet-induced obesity and improves fatty acid oxidation in the muscle

DEFF Research Database (Denmark)

Pedersen, Line; Holkmann Olsen, Caroline; Pedersen, Bente Klarlund

2012-01-01

Serum levels and muscle expression of the chemokine CXCL1 increase markedly in response to exercise in mice. Because several studies have established muscle-derived factors as important contributors of metabolic effects of exercise, this study aimed at investigating the effect of increased expres...... in muscle angiogenesis. In conclusion, our data show that overexpression of CXCL1 within a physiological range attenuates diet-induced obesity, likely mediated through a CXCL1-induced improvement of fatty acid oxidation and oxidative capacity in skeletal muscle tissue....

Roles of oxygen radicals and elastase in citric acid-induced airway constriction of guinea-pigs

OpenAIRE

Lai, Y -L; Chiou, W -Y; Lu, F J; Chiang, L Y

1999-01-01

Antioxidants attenuate noncholinergic airway constriction. To further investigate the relationship between tachykinin-mediated airway constriction and oxygen radicals, we explored citric acid-induced bronchial constriction in 48 young Hartley strain guinea-pigs, divided into six groups: control; citric acid; hexa(sulphobutyl)fullerenes+citric acid; hexa(sulphobutyl)fullerenes+phosphoramidon+citric acid; dimethylthiourea (DMTU)+citric acid; and DMTU+phosphoramidon+citric acid. Hexa(sulphobutyl...

Alisol B 23-acetate protects against ANIT-induced hepatotoxity and cholestasis, due to FXR-mediated regulation of transporters and enzymes involved in bile acid homeostasis

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Meng, Qiang; Chen, Xin-li; Wang, Chang-yuan; Liu, Qi; Sun, Hui-jun; Sun, Peng-yuan; Huo, Xiao-kui; Liu, Zhi-hao; Yao, Ji-hong; Liu, Ke-xin, E-mail: kexinliu@dlmedu.edu.cn

2015-03-15

Intrahepatic cholestasis is a clinical syndrome with systemic and intrahepatic accumulation of excessive toxic bile acids that ultimately cause hepatobiliary injury. Appropriate regulation of bile acids in hepatocytes is critically important for protection against liver injury. In the present study, we characterized the protective effect of alisol B 23-acetate (AB23A), a natural triterpenoid, on alpha-naphthylisothiocyanate (ANIT)-induced liver injury and intrahepatic cholestasis in mice and further elucidated the mechanisms in vivo and in vitro. AB23A treatment dose-dependently protected against liver injury induced by ANIT through reducing hepatic uptake and increasing efflux of bile acid via down-regulation of hepatic uptake transporters (Ntcp) and up-regulation of efflux transporter (Bsep, Mrp2 and Mdr2) expression. Furthermore, AB23A reduced bile acid synthesis through repressing Cyp7a1 and Cyp8b1, increased bile acid conjugation through inducing Bal, Baat and bile acid metabolism through an induction in gene expression of Sult2a1. We further demonstrate the involvement of farnesoid X receptor (FXR) in the hepatoprotective effect of AB23A. The changes in transporters and enzymes, as well as ameliorative liver histology in AB23A-treated mice were abrogated by FXR antagonist guggulsterone in vivo. In vitro evidences also directly demonstrated the effect of AB23A on FXR activation in a dose-dependent manner using luciferase reporter assay in HepG2 cells. In conclusion, AB23A produces protective effect against ANIT-induced hepatotoxity and cholestasis, due to FXR-mediated regulation of transporters and enzymes. - Highlights: • AB23A has at least three roles in protection against ANIT-induced liver injury. • AB23A decreases Ntcp, and increases Bsep, Mrp2 and Mdr2 expression. • AB23A represses Cyp7a1 and Cyp8b1 through inducing Shp and Fgf15 expression. • AB23A increases bile acid metabolism through inducing Sult2a1 expression. • FXR activation is involved

Alisol B 23-acetate protects against ANIT-induced hepatotoxity and cholestasis, due to FXR-mediated regulation of transporters and enzymes involved in bile acid homeostasis

International Nuclear Information System (INIS)

Meng, Qiang; Chen, Xin-li; Wang, Chang-yuan; Liu, Qi; Sun, Hui-jun; Sun, Peng-yuan; Huo, Xiao-kui; Liu, Zhi-hao; Yao, Ji-hong; Liu, Ke-xin

2015-01-01

Intrahepatic cholestasis is a clinical syndrome with systemic and intrahepatic accumulation of excessive toxic bile acids that ultimately cause hepatobiliary injury. Appropriate regulation of bile acids in hepatocytes is critically important for protection against liver injury. In the present study, we characterized the protective effect of alisol B 23-acetate (AB23A), a natural triterpenoid, on alpha-naphthylisothiocyanate (ANIT)-induced liver injury and intrahepatic cholestasis in mice and further elucidated the mechanisms in vivo and in vitro. AB23A treatment dose-dependently protected against liver injury induced by ANIT through reducing hepatic uptake and increasing efflux of bile acid via down-regulation of hepatic uptake transporters (Ntcp) and up-regulation of efflux transporter (Bsep, Mrp2 and Mdr2) expression. Furthermore, AB23A reduced bile acid synthesis through repressing Cyp7a1 and Cyp8b1, increased bile acid conjugation through inducing Bal, Baat and bile acid metabolism through an induction in gene expression of Sult2a1. We further demonstrate the involvement of farnesoid X receptor (FXR) in the hepatoprotective effect of AB23A. The changes in transporters and enzymes, as well as ameliorative liver histology in AB23A-treated mice were abrogated by FXR antagonist guggulsterone in vivo. In vitro evidences also directly demonstrated the effect of AB23A on FXR activation in a dose-dependent manner using luciferase reporter assay in HepG2 cells. In conclusion, AB23A produces protective effect against ANIT-induced hepatotoxity and cholestasis, due to FXR-mediated regulation of transporters and enzymes. - Highlights: • AB23A has at least three roles in protection against ANIT-induced liver injury. • AB23A decreases Ntcp, and increases Bsep, Mrp2 and Mdr2 expression. • AB23A represses Cyp7a1 and Cyp8b1 through inducing Shp and Fgf15 expression. • AB23A increases bile acid metabolism through inducing Sult2a1 expression. • FXR activation is involved

Jasmonic acid signaling modulates ozone-induced hypersensitive cell death.

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Rao, M V; Lee, H; Creelman, R A; Mullet, J E; Davis, K R

2000-09-01

Recent studies suggest that cross-talk between salicylic acid (SA)-, jasmonic acid (JA)-, and ethylene-dependent signaling pathways regulates plant responses to both abiotic and biotic stress factors. Earlier studies demonstrated that ozone (O(3)) exposure activates a hypersensitive response (HR)-like cell death pathway in the Arabidopsis ecotype Cvi-0. We now have confirmed the role of SA and JA signaling in influencing O(3)-induced cell death. Expression of salicylate hydroxylase (NahG) in Cvi-0 reduced O(3)-induced cell death. Methyl jasmonate (Me-JA) pretreatment of Cvi-0 decreased O(3)-induced H(2)O(2) content and SA concentrations and completely abolished O(3)-induced cell death. Cvi-0 synthesized as much JA as did Col-0 in response to O(3) exposure but exhibited much less sensitivity to exogenous Me-JA. Analyses of the responses to O(3) of the JA-signaling mutants jar1 and fad3/7/8 also demonstrated an antagonistic relationship between JA- and SA-signaling pathways in controlling the magnitude of O(3)-induced HR-like cell death.

Auxin Response Factors (ARFs are potential mediators of auxin action in tomato response to biotic and abiotic stress (Solanum lycopersicum.

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Sarah Bouzroud

Full Text Available Survival biomass production and crop yield are heavily constrained by a wide range of environmental stresses. Several phytohormones among which abscisic acid (ABA, ethylene and salicylic acid (SA are known to mediate plant responses to these stresses. By contrast, the role of the plant hormone auxin in stress responses remains so far poorly studied. Auxin controls many aspects of plant growth and development, and Auxin Response Factors play a key role in the transcriptional activation or repression of auxin-responsive genes through direct binding to their promoters. As a mean to gain more insight on auxin involvement in a set of biotic and abiotic stress responses in tomato, the present study uncovers the expression pattern of SlARF genes in tomato plants subjected to biotic and abiotic stresses. In silico mining of the RNAseq data available through the public TomExpress web platform, identified several SlARFs as responsive to various pathogen infections induced by bacteria and viruses. Accordingly, sequence analysis revealed that 5' regulatory regions of these SlARFs are enriched in biotic and abiotic stress-responsive cis-elements. Moreover, quantitative qPCR expression analysis revealed that many SlARFs were differentially expressed in tomato leaves and roots under salt, drought and flooding stress conditions. Further pointing to the putative role of SlARFs in stress responses, quantitative qPCR expression studies identified some miRNA precursors as potentially involved in the regulation of their SlARF target genes in roots exposed to salt and drought stresses. These data suggest an active regulation of SlARFs at the post-transcriptional level under stress conditions. Based on the substantial change in the transcript accumulation of several SlARF genes, the data presented in this work strongly support the involvement of auxin in stress responses thus enabling to identify a set of candidate SlARFs as potential mediators of biotic and abiotic

Heterotrimeric G proteins-mediated resistance to necrotrophic pathogens includes mechanisms independent of salicylic acid-, jasmonic acid/ethylene- and abscisic acid-mediated defense signaling.

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Trusov, Yuri; Sewelam, Nasser; Rookes, James Edward; Kunkel, Matt; Nowak, Ekaterina; Schenk, Peer Martin; Botella, José Ramón

2009-04-01

Heterotrimeric G proteins are involved in the defense response against necrotrophic fungi in Arabidopsis. In order to elucidate the resistance mechanisms involving heterotrimeric G proteins, we analyzed the effects of the Gβ (subunit deficiency in the mutant agb1-2 on pathogenesis-related gene expression, as well as the genetic interaction between agb1-2 and a number of mutants of established defense pathways. Gβ-mediated signaling suppresses the induction of salicylic acid (SA)-, jasmonic acid (JA)-, ethylene (ET)- and abscisic acid (ABA)-dependent genes during the initial phase of the infection with Fusarium oxysporum (up to 48 h after inoculation). However, at a later phase it enhances JA/ET-dependent genes such as PDF1.2 and PR4. Quantification of the Fusarium wilt symptoms revealed that Gβ- and SA-deficient mutants were more susceptible than wild-type plants, whereas JA- and ET-insensitive and ABA-deficient mutants demonstrated various levels of resistance. Analysis of the double mutants showed that the Gβ-mediated resistance to F. oxysporum and Alternaria brassicicola was mostly independent of all of the previously mentioned pathways. However, the progressive decay of agb1-2 mutants was compensated by coi1-21 and jin1-9 mutations, suggesting that at this stage of F. oxysporum infection Gβ acts upstream of COI1 and ATMYC2 in JA signaling. © 2008 The Authors. Journal compilation © 2008 Blackwell Publishing Ltd.

Vitamin A active metabolite, all-trans retinoic acid, induces spinal cord sensitization. II. Effects after intrathecal administration

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Alique, M; Lucio, F J; Herrero, J F

2006-01-01

Background and purpose: In our previous study (see accompanying paper) we observed that all-trans retinoic acid (ATRA) p.o. induces changes in spinal cord neuronal responses similar to those observed in inflammation-induced sensitization. In the present study we assessed the it. effects of ATRA, and its mechanisms of action. Experimental approach: The effects of all drugs were studied after it. administration in nociceptive withdrawal reflexes using behavioural tests in awake male Wistar rats. Key results: The administration of ATRA in normal rats induced a dose-dependent enhancement of nociceptive responses to noxious mechanical and thermal stimulation, as well as responses to innocuous stimulation. The intensity of the responses was similar to that observed in non-treated animals after carrageenan-induced inflammation. The effect induced by ATRA was fully prevented by the previous administration of the retinoic acid receptor (RAR) pan-antagonist LE540 but not by the retinoid X receptor (RXR) pan-antagonist HX531, suggesting a selective action on spinal cord RARs. The COX inhibitor dexketoprofen and the interleukin-1 receptor antagonist IL-1ra inhibited ATRA effect. The results indicate that COX and interleukin-1 are involved in the effects of ATRA in the spinal cord, similar to that seen in inflammation. Conclusions and implications: In conclusion, ATRA induces changes in the spinal cord similar to those observed in inflammation. The sensitization-like effect induced by ATRA was mediated by RARs and associated with a modulation of COX-2 and interleukin-1 activities. ATRA might be involved in the mechanisms underlying the initiation and/or maintenance of sensitization in the spinal cord. PMID:16847438

Ezrin dephosphorylation/downregulation contributes to ursolic acid-mediated cell death in human leukemia cells

International Nuclear Information System (INIS)

Li, G; Zhou, T; Liu, L; Chen, J; Zhao, Z; Peng, Y; Li, P; Gao, N

2013-01-01

Ezrin links the actin filaments with the cell membrane and has a functional role in the apoptotic process. It appears clear that ezrin is directly associated with Fas, leading to activation of caspase cascade and cell death. However, the exact role of ezrin in ursolic acid (UA)-induced apoptosis remains unclear. In this study, we show for the first time that UA induces apoptosis in both transformed and primary leukemia cells through dephosphorylation/downregulation of ezrin, association and polarized colocalization of Fas and ezrin, as well as formation of death-inducing signaling complex. These events are dependent on Rho-ROCK1 signaling pathway. Knockdown of ezrin enhanced cell death mediated by UA, whereas overexpression of ezrin attenuated UA-induced apoptosis. Our in vivo study also showed that UA-mediated inhibition of tumor growth of mouse leukemia xenograft model is in association with the dephosphorylation/downregulation of ezrin. Such findings suggest that the cytoskeletal protein ezrin may represent an attractive target for UA-mediated lethality in human leukemia cells

Salicylic acid is an indispensable component of the Ny-1 resistance-gene-mediated response against Potato virus Y infection in potato.

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Baebler, Š; Witek, K; Petek, M; Stare, K; Tušek-Žnidarič, M; Pompe-Novak, M; Renaut, J; Szajko, K; Strzelczyk-Żyta, D; Marczewski, W; Morgiewicz, K; Gruden, K; Hennig, J

2014-03-01

The purpose of the study was to investigate the role of salicylic acid (SA) signalling in Ny-1-mediated hypersensitive resistance (HR) of potato (Solanum tuberosum L.) to Potato virus Y (PVY). The responses of the Ny-1 allele in the Rywal potato cultivar and transgenic NahG-Rywal potato plants that do not accumulate SA were characterized at the cytological, biochemical, transcriptome, and proteome levels. Analysis of noninoculated and inoculated leaves revealed that HR lesions started to develop from 3 d post inoculation and completely restricted the virus spread. At the cytological level, features of programmed cell death in combination with reactive oxygen species burst were observed. In response to PVY infection, SA was synthesized de novo. The lack of SA accumulation in the NahG plants led to the disease phenotype due to unrestricted viral spreading. Grafting experiments show that SA has a critical role in the inhibition of PVY spreading in parenchymal tissue, but not in vascular veins. The whole transcriptome analysis confirmed the central role of SA in orchestrating Ny-1-mediated responses and showed that the absence of SA leads to significant changes at the transcriptome level, including a delay in activation of expression of genes known to participate in defence responses. Moreover, perturbations in the expression of hormonal signalling genes were detected, shown as a switch from SA to jasmonic acid/ethylene signalling. Viral multiplication in the NahG plants was accompanied by downregulation of photosynthesis genes and activation of multiple energy-producing pathways.

The Na+/H+ exchanger controls deoxycholic acid-induced apoptosis by a H+-activated, Na+-dependent ionic shift in esophageal cells.

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Aaron Goldman

Full Text Available Apoptosis resistance is a hallmark of cancer cells. Typically, bile acids induce apoptosis. However during gastrointestinal (GI tumorigenesis the cancer cells develop resistance to bile acid-induced cell death. To understand how bile acids induce apoptosis resistance we first need to identify the molecular pathways that initiate apoptosis in response to bile acid exposure. In this study we examined the mechanism of deoxycholic acid (DCA-induced apoptosis, specifically the role of Na(+/H(+ exchanger (NHE and Na(+ influx in esophageal cells. In vitro studies revealed that the exposure of esophageal cells (JH-EsoAd1, CP-A to DCA (0.2 mM-0.5 mM caused lysosomal membrane perturbation and transient cytoplasmic acidification. Fluorescence microscopy in conjunction with atomic absorption spectrophotometry demonstrated that this effect on lysosomes correlated with influx of Na(+, subsequent loss of intracellular K(+, an increase of Ca(2+ and apoptosis. However, ethylisopropyl-amiloride (EIPA, a selective inhibitor of NHE, prevented Na(+, K(+ and Ca(2+ changes and caspase 3/7 activation induced by DCA. Ouabain and amphotericin B, two drugs that increase intracellular Na(+ levels, induced similar changes as DCA (ion imbalance, caspase3/7 activation. On the contrary, DCA-induced cell death was inhibited by medium with low a Na(+ concentrations. In the same experiments, we exposed rat ileum ex-vivo to DCA with or without EIPA. Severe tissue damage and caspase-3 activation was observed after DCA treatment, but EIPA almost fully prevented this response. In summary, NHE-mediated Na(+ influx is a critical step leading to DCA-induced apoptosis. Cells tolerate acidification but evade DCA-induced apoptosis if NHE is inhibited. Our data suggests that suppression of NHE by endogenous or exogenous inhibitors may lead to apoptosis resistance during GI tumorigenesis.

Blood ketone response to norepinephrine-induced free fatty acid in diabetes

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Blackard, W G; Omori, Yoshiaki

1963-04-18

During 90-minute norepinephrine infusions, blood free fatty acid and ketone responses of Japanese nondiabetic and diabetic subjects were determined. Nonobese diabetic subjects with and without fasting hyperglycemia demonstrated significantly greater blood ketone elevations than nondiabetics. An inverse correlation between obesity and blood ketone response to nonrepinephrine was observed in diabetics. This correlation could not be attributed to varying degrees of fasting hyperglycemia or free fatty acid elevation. Nonobese diabetics with mild fasting hyperglycemia (90 to 150 mg%) exhibited an unexpected greater increase in blood ketones than nonobese diabetics with moderate fasting hyperglycemia (150 to 250 mg%). Differences in free fatty acid elevations were not responsible for this apparent paradox. The magnitude of the hyperketonemic response, though dependent on free fatty elevation, seemed more sensitive to the degree of obesity and the fasting blood glucose level. Fractional ketone body measurements attributed the blood ketone elevations predominantly to ..beta..-hydroxybutyric acid increases. 43 references, 6 figures, 1 table.

Acid resistance and response to pH-induced stress in two Lactobacillus plantarum strains with probiotic potential.

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Šeme, H; Gjuračić, K; Kos, B; Fujs, Š; Štempelj, M; Petković, H; Šušković, J; Bogovič Matijašić, B; Kosec, G

2015-01-01

Two new Lactobacillus plantarum strains, KR6-DSM 28780 and M5 isolated from sour turnip and traditional dried fresh cheese, respectively, were evaluated for species identity, antibiotic susceptibility, resistance to gastrointestinal conditions and adaptive response to low pH. Resistance mechanisms involved in the adaptation to acid-induced stress in these two strains were investigated by quantitative PCR of the atpA, cfa1, mleS and hisD genes. In addition to absence of antibiotic resistance, the two L. plantarum strains showed excellent survival rates at pH values as low as 2.4. Adaptive response to low pH was clearly observed in both strains; strain KR6 was superior to M5, as demonstrated by its ability to survive during 3 h incubation at pH 2.0 upon adaptation to moderately acidic conditions. In contrast, acid adaptation did not significantly affect the survival rate during simulated passage through the gastrointestinal tract. In both strains, induction of histidine biosynthesis (hisD) was upregulated during the acid adaptation response. In addition, significant upregulation of the cfa1 gene, involved in modulation of membrane fatty acid composition, was observed during the adaptation phase in strain KR6 but not in strain M5. Cells adapted to moderately acidic conditions also showed a significantly increased viability after the lyophilisation procedure, a cross-protection phenomenon providing additional advantage in probiotic application.

Acid-induced autophagy protects human lung cancer cells from apoptosis by activating ER stress.

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Xie, Wen-Yue; Zhou, Xiang-Dong; Li, Qi; Chen, Ling-Xiu; Ran, Dan-Hua

2015-12-10

An acidic tumor microenvironment exists widely in solid tumors. However, the detailed mechanism of cell survival under acidic stress remains unclear. The aim of this study is to clarify whether acid-induced autophagy exists and to determine the function and mechanism of autophagy in lung cancer cells. We have found that acute low pH stimulated autophagy by increasing LC3-positive punctate vesicles, increasing LC3 II expression levels and reducing p62 protein levels. Additionally, autophagy was inhibited by the addition of Baf or knockdown of Beclin 1, and cell apoptosis was increased markedly. In mouse tumors, the expression of cleaved caspase3 and p62 was enhanced by oral treatment with sodium bicarbonate, which can raise the intratumoral pH. Furthermore, the protein levels of ER stress markers, including p-PERK, p-eIF2α, CHOP, XBP-1s and GRP78, were also increased in response to acidic pH. The antioxidant NAC, which reduces ROS accumulation, alleviated acid-mediated ER stress and autophagy, and knocking down GRP78 reduced autophagy activation under acidic conditions, which suggests that autophagy was induced by acidic pH through ER stress. Taken together, these results indicate that the acidic microenvironment in non-small cell lung cancer cells promotes autophagy by increasing ROS-ER stress, which serves as a survival adaption in this setting. Copyright © 2015 Elsevier Inc. All rights reserved.

Calcium-mediated signaling and calmodulin-dependent kinase regulate hepatocyte-inducible nitric oxide synthase expression.

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Zhang, Baochun; Crankshaw, Will; Nesemeier, Ryan; Patel, Jay; Nweze, Ikenna; Lakshmanan, Jaganathan; Harbrecht, Brian G

2015-02-01

Induced nitric oxide synthase (iNOS) is induced in hepatocytes by shock and inflammatory stimuli. Excessive NO from iNOS mediates shock-induced hepatic injury and death, so understanding the regulation of iNOS will help elucidate the pathophysiology of septic shock. In vitro, cytokines induce iNOS expression through activation of signaling pathways including mitogen-activated protein kinases and nuclear factor κB. Cytokines also induce calcium (Ca(2+)) mobilization and activate calcium-mediated intracellular signaling pathways, typically through activation of calmodulin-dependent kinases (CaMK). Calcium regulates NO production in macrophages but the role of calcium and calcium-mediated signaling in hepatocyte iNOS expression has not been defined. Primary rat hepatocytes were isolated, cultured, and induced to produce NO with proinflammatory cytokines. Calcium mobilization and Ca(2+)-mediated signaling were altered with ionophore, Ca(2+) channel blockers, and inhibitors of CaMK. The Ca(2+) ionophore A23187 suppressed cytokine-stimulated NO production, whereas Ethylene glycol tetraacetic acid and nifedipine increased NO production, iNOS messenger RNA, and iNOS protein expression. Inhibition of CaMK with KN93 and CBD increased NO production but the calcineurin inhibitor FK 506 decreased iNOS expression. These data demonstrate that calcium-mediated signaling regulates hepatocyte iNOS expression and does so through a mechanism independent of calcineurin. Changes in intracellular calcium levels may regulate iNOS expression during hepatic inflammation induced by proinflammatory cytokines. Copyright © 2015 Elsevier Inc. All rights reserved.

Bile Acid-Mediated Sphingosine-1-Phosphate Receptor 2 Signaling Promotes Neuroinflammation during Hepatic Encephalopathy in Mice

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Matthew McMillin

2017-07-01

Full Text Available Hepatic encephalopathy (HE is a neuropsychiatric complication that occurs due to deteriorating hepatic function and this syndrome influences patient quality of life, clinical management strategies and survival. During acute liver failure, circulating bile acids increase due to a disruption of the enterohepatic circulation. We previously identified that bile acid-mediated signaling occurs in the brain during HE and contributes to cognitive impairment. However, the influences of bile acids and their downstream signaling pathways on HE-induced neuroinflammation have not been assessed. Conjugated bile acids, such as taurocholic acid (TCA, can activate sphingosine-1-phosphate receptor 2 (S1PR2, which has been shown to promote immune cell infiltration and inflammation in other models. The current study aimed to assess the role of bile-acid mediated S1PR2 signaling in neuroinflammation and disease progression during azoxymethane (AOM-induced HE in mice. Our findings demonstrate a temporal increase of bile acids in the cortex during AOM-induced HE and identified that cortical bile acids were elevated as an early event in this model. In order to classify the specific bile acids that were elevated during HE, a metabolic screen was performed and this assay identified that TCA was increased in the serum and cortex during AOM-induced HE. To reduce bile acid concentrations in the brain, mice were fed a diet supplemented with cholestyramine, which alleviated neuroinflammation by reducing proinflammatory cytokine expression in the cortex compared to the control diet-fed AOM-treated mice. S1PR2 was expressed primarily in neurons and TCA treatment increased chemokine ligand 2 mRNA expression in these cells. The infusion of JTE-013, a S1PR2 antagonist, into the lateral ventricle prior to AOM injection protected against neurological decline and reduced neuroinflammation compared to DMSO-infused AOM-treated mice. Together, this identifies that reducing bile acid

Stress- and glucocorticoid-induced priming of neuroinflammatory responses: potential mechanisms of stress-induced vulnerability to drugs of abuse.

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Frank, Matthew G; Watkins, Linda R; Maier, Steven F

2011-06-01

Stress and stress-induced glucocorticoids (GCs) sensitize drug abuse behavior as well as the neuroinflammatory response to a subsequent pro-inflammatory challenge. Stress also predisposes or sensitizes individuals to develop substance abuse. There is an emerging evidence that glia and glia-derived neuroinflammatory mediators play key roles in the development of drug abuse. Drugs of abuse such as opioids, psychostimulants, and alcohol induce neuroinflammatory mediators such as pro-inflammatory cytokines (e.g. interleukin (IL)-1β), which modulate drug reward, dependence, and tolerance as well as analgesic properties. Drugs of abuse may directly activate microglial and astroglial cells via ligation of Toll-like receptors (TLRs), which mediate the innate immune response to pathogens as well as xenobiotic agents (e.g. drugs of abuse). The present review focuses on understanding the immunologic mechanism(s) whereby stress primes or sensitizes the neuroinflammatory response to drugs of abuse and explores whether stress- and GC-induced sensitization of neuroimmune processes predisposes individuals to drug abuse liability and the role of neuroinflammatory mediators in the development of drug addiction. Copyright © 2011 Elsevier Inc. All rights reserved.

Abscisic acid-regulated protein degradation causes osmotic stress-induced accumulation of branched-chain amino acids in Arabidopsis thaliana.

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Huang, Tengfang; Jander, Georg

2017-10-01

Whereas proline accumulates through de novo biosynthesis in plants subjected to osmotic stress, leucine, isoleucine, and valine accumulation in drought-stressed Arabidopsis thaliana is caused by abscisic acid-regulated protein degradation. In response to several kinds of abiotic stress, plants greatly increase their accumulation of free amino acids. Although stress-induced proline increases have been studied the most extensively, the fold-increase of other amino acids, in particular branched-chain amino acids (BCAAs; leucine, isoleucine, and valine), is often higher than that of proline. In Arabidopsis thaliana (Arabidopsis), BCAAs accumulate in response to drought, salt, mannitol, polyethylene glycol, herbicide treatment, and nitrogen starvation. Plants that are deficient in abscisic acid signaling accumulate lower amounts of BCAAs, but not proline and most other amino acids. Previous bioinformatic studies had suggested that amino acid synthesis, rather than protein degradation, is responsible for the observed BCAA increase in osmotically stressed Arabidopsis. However, whereas treatment with the protease inhibitor MG132 decreased drought-induced BCAA accumulation, inhibition of BCAA biosynthesis with the acetolactate synthase inhibitors chlorsulfuron and imazapyr did not. Additionally, overexpression of BRANCHED-CHAIN AMINO ACID TRANSFERASE2 (BCAT2), which is upregulated in response to osmotic stress and functions in BCAA degradation, decreased drought-induced BCAA accumulation. Together, these results demonstrate that BCAA accumulation in osmotically stressed Arabidopsis is primarily the result of protein degradation. After relief of the osmotic stress, BCAA homeostasis is restored over time by amino acid degradation involving BCAT2. Thus, drought-induced BCAA accumulation is different from that of proline, which is accumulated due to de novo synthesis in an abscisic acid-independent manner and remains elevated for a more prolonged period of time after removal of

Myostatin induces insulin resistance via Casitas B-lineage lymphoma b (Cblb)-mediated degradation of insulin receptor substrate 1 (IRS1) protein in response to high calorie diet intake.

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Bonala, Sabeera; Lokireddy, Sudarsanareddy; McFarlane, Craig; Patnam, Sreekanth; Sharma, Mridula; Kambadur, Ravi

2014-03-14

To date a plethora of evidence has clearly demonstrated that continued high calorie intake leads to insulin resistance and type-2 diabetes with or without obesity. However, the necessary signals that initiate insulin resistance during high calorie intake remain largely unknown. Our results here show that in response to a regimen of high fat or high glucose diets, Mstn levels were induced in muscle and liver of mice. High glucose- or fat-mediated induction of Mstn was controlled at the level of transcription, as highly conserved carbohydrate response and sterol-responsive (E-box) elements were present in the Mstn promoter and were revealed to be critical for ChREBP (carbohydrate-responsive element-binding protein) or SREBP1c (sterol regulatory element-binding protein 1c) regulation of Mstn expression. Further molecular analysis suggested that the increased Mstn levels (due to high glucose or fatty acid loading) resulted in increased expression of Cblb in a Smad3-dependent manner. Casitas B-lineage lymphoma b (Cblb) is an ubiquitin E3 ligase that has been shown to specifically degrade insulin receptor substrate 1 (IRS1) protein. Consistent with this, our results revealed that elevated Mstn levels specifically up-regulated Cblb, resulting in enhanced ubiquitin proteasome-mediated degradation of IRS1. In addition, over expression or knock down of Cblb had a major impact on IRS1 and pAkt levels in the presence or absence of insulin. Collectively, these observations strongly suggest that increased glucose levels and high fat diet, both, result in increased circulatory Mstn levels. The increased Mstn in turn is a potent inducer of insulin resistance by degrading IRS1 protein via the E3 ligase, Cblb, in a Smad3-dependent manner.

FOXO3-mediated up-regulation of Bim contributes to rhein-induced cancer cell apoptosis.

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Wang, Jiao; Liu, Shu; Yin, Yancun; Li, Mingjin; Wang, Bo; Yang, Li; Jiang, Yangfu

2015-03-01

The anthraquinone compound rhein is a natural agent in the traditional Chinese medicine rhubarb. Preclinical studies demonstrate that rhein has anticancer activity. Treatment of a variety of cancer cells with rhein may induce apoptosis. Here, we report that rhein induces atypical unfolded protein response in breast cancer MCF-7 cells and hepatoma HepG2 cells. Rhein induces CHOP expression, eIF2α phosphorylation and caspase cleavage, while it does not induce glucose-regulated protein 78 (GRP78) expression in both MCF-7 and HepG2 cells. Meanwhile, rhein inhibits thapsigargin-induced GRP78 expression and X box-binding protein 1 splicing. In addition, rhein inhibits Akt phosphorylation and stimulates FOXO transactivation activity. Rhein induces Bim expression in MCF-7 and HepG2 cells, which can be abrogated by FOXO3a knockdown. Knockdown of FOXO3a or Bim abrogates rhein-induced caspase cleavage and apoptosis. The chemical chaperone 4-phenylbutyrate acid antagonizes the induction of FOXO activation, Bim expression and caspase cleavage by rhein, indicating that protein misfolding may be involved in triggering these deleterious effects. We conclude that FOXO3a-mediated up-regulation of Bim is a key mechanism underlying rhein-induced cancer cells apoptosis.

The plastidial retrograde signal methyl erythritol cyclopyrophosphate is a regulator of salicylic acid and jasmonic acid crosstalk

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Lemos, Mark; Xiao, Yanmei; Bjornson, Marta; Wang, Jin-zheng; Hicks, Derrick; de Souza, Amancio; Wang, Chang-Quan; Yang, Panyu; Ma, Shisong; Dinesh-Kumar, Savithramma; Dehesh, Katayoon

2016-01-01

The exquisite harmony between hormones and their corresponding signaling pathways is central to prioritizing plant responses to simultaneous and/or successive environmental trepidations. The crosstalk between jasmonic acid (JA) and salicylic acid (SA) is an established effective mechanism that optimizes and tailors plant adaptive responses. However, the underlying regulatory modules of this crosstalk are largely unknown. Global transcriptomic analyses of mutant plants (ceh1) with elevated levels of the stress-induced plastidial retrograde signaling metabolite 2-C-methyl-D-erythritol cyclopyrophosphate (MEcPP) revealed robustly induced JA marker genes, expected to be suppressed by the presence of constitutively high SA levels in the mutant background. Analyses of a range of genotypes with varying SA and MEcPP levels established the selective role of MEcPP-mediated signal(s) in induction of JA-responsive genes in the presence of elevated SA. Metabolic profiling revealed the presence of high levels of the JA precursor 12-oxo-phytodienoic acid (OPDA), but near wild type levels of JA in the ceh1 mutant plants. Analyses of coronatine-insensitive 1 (coi1)/ceh1 double mutant plants confirmed that the MEcPP-mediated induction is JA receptor COI1 dependent, potentially through elevated OPDA. These findings identify MEcPP as a previously unrecognized central regulatory module that induces JA-responsive genes in the presence of high SA, thereby staging a multifaceted plant response within the environmental context. PMID:26733689

Hormesis in Cholestatic Liver Disease; Preconditioning with Low Bile Acid Concentrations Protects against Bile Acid-Induced Toxicity.

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Esther M Verhaag

Full Text Available Cholestasis is characterized by accumulation of bile acids and inflammation, causing hepatocellular damage. Still, liver damage markers are highest in acute cholestasis and drop when this condition becomes chronic, indicating that hepatocytes adapt towards the hostile environment. This may be explained by a hormetic response in hepatocytes that limits cell death during cholestasis.To investigate the mechanisms that underlie the hormetic response that protect hepatocytes against experimental cholestatic conditions.HepG2.rNtcp cells were preconditioned (24 h with sub-apoptotic concentrations (0.1-50 μM of various bile acids, the superoxide donor menadione, TNF-α or the Farsenoid X Receptor agonist GW4064, followed by a challenge with the apoptosis-inducing bile acid glycochenodeoxycholic acid (GCDCA; 200 μM for 4 h, menadione (50 μM, 6 h or cytokine mixture (CM; 6 h. Levels of apoptotic and necrotic cell death, mRNA expression of the bile salt export pump (ABCB11 and bile acid sensors, as well as intracellular GCDCA levels were analyzed.Preconditioning with the pro-apoptotic bile acids GCDCA, taurocholic acid, or the protective bile acids (tauroursodeoxycholic acid reduced GCDCA-induced caspase-3/7 activity in HepG2.rNtcp cells. Bile acid preconditioning did not induce significant levels of necrosis in GCDCA-challenged HepG2.rNtcp cells. In contrast, preconditioning with cholic acid, menadione or TNF-α potentiated GCDCA-induced apoptosis. GCDCA preconditioning specifically reduced GCDCA-induced cell death and not CM- or menadione-induced apoptosis. The hormetic effect of GCDCA preconditioning was concentration- and time-dependent. GCDCA-, CDCA- and GW4064- preconditioning enhanced ABCB11 mRNA levels, but in contrast to the bile acids, GW4064 did not significantly reduce GCDCA-induced caspase-3/7 activity. The GCDCA challenge strongly increased intracellular levels of this bile acid, which was not lowered by GCDCA

Triphenyl phosphate-induced developmental toxicity in zebrafish: Potential role of the retinoic acid receptor

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Isales, Gregory M.; Hipszer, Rachel A.; Raftery, Tara D. [Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC (United States); Chen, Albert; Stapleton, Heather M. [Division of Environmental Sciences and Policy, Nicholas School of the Environment, Duke University, Durham, NC (United States); Volz, David C., E-mail: volz@mailbox.sc.edu [Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC (United States)

2015-04-15

Highlights: • Triphenyl phosphate-induced toxicity in zebrafish embryos is enhanced in the presence of a retinoic acid receptor antagonist. • Triphenyl phosphate uptake or metabolism within zebrafish embryos is not altered in the presence of a retinoic acid receptor antagonist. • Triphenyl phosphate decreases expression of cytochrome P450 26a1 in zebrafish embryos. • Triphenyl phosphate inhibits retinoic acid-induced activation of human retinoic acid receptors. - Abstract: Using zebrafish as a model, we previously reported that developmental exposure to triphenyl phosphate (TPP) – a high-production volume organophosphate-based flame retardant – results in dioxin-like cardiac looping impairments that are independent of the aryl hydrocarbon receptor. Using a pharmacologic approach, the objective of this study was to investigate the potential role of retinoic acid receptor (RAR) – a nuclear receptor that regulates vertebrate heart morphogenesis – in mediating TPP-induced developmental toxicity in zebrafish. We first revealed that static exposure of zebrafish from 5–72 h post-fertilization (hpf) to TPP in the presence of non-toxic concentrations of an RAR antagonist (BMS493) significantly enhanced TPP-induced toxicity (relative to TPP alone), even though identical non-toxic BMS493 concentrations mitigated retinoic acid (RA)-induced toxicity. BMS493-mediated enhancement of TPP toxicity was not a result of differential TPP uptake or metabolism, as internal embryonic doses of TPP and diphenyl phosphate (DPP) – a primary TPP metabolite – were not different in the presence or absence of BMS493. Using real-time PCR, we then quantified the relative change in expression of cytochrome P450 26a1 (cyp26a1) – a major target gene for RA-induced RAR activation in zebrafish – and found that RA and TPP exposure resulted in a ∼5-fold increase and decrease in cyp26a1 expression, respectively, relative to vehicle-exposed embryos. To address whether TPP may

Chemotaxis to cyclic AMP and folic acid is mediated by different G proteins in Dictyostelium discoideum

NARCIS (Netherlands)

Kesbeke, Fanja; Haastert, Peter J.M. van; Wit, René J.W. de; Snaar-Jagalska, B. Ewa

1990-01-01

Mutant Frigid A (fgdA) of Dictyostelium discoideum is defective in a functional Gα2 subunit of a G protein and is characterized by a complete blockade of the cyclic AMP-mediated sensory transduction steps, including cyclic AMP relay, chemotaxis and the cyclic GMP response. Folic acid-mediated

Nrp2 is sufficient to instruct circuit formation of mitral-cells to mediate odour-induced attractive social responses.

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Inokuchi, Kasumi; Imamura, Fumiaki; Takeuchi, Haruki; Kim, Ryang; Okuno, Hiroyuki; Nishizumi, Hirofumi; Bito, Haruhiko; Kikusui, Takefumi; Sakano, Hitoshi

2017-07-21

Odour information induces various innate responses that are critical to the survival of the individual and for the species. An axon guidance molecule, Neuropilin 2 (Nrp2), is known to mediate targeting of olfactory sensory neurons (primary neurons), to the posteroventral main olfactory bulb (PV MOB) in mice. Here we report that Nrp2-positive (Nrp2 + ) mitral cells (MCs, second-order neurons) play crucial roles in transmitting attractive social signals from the PV MOB to the anterior part of medial amygdala (MeA). Semaphorin 3F, a repulsive ligand to Nrp2, regulates both migration of Nrp2 + MCs to the PV MOB and their axonal projection to the anterior MeA. In the MC-specific Nrp2 knockout mice, circuit formation of Nrp2 + MCs and odour-induced attractive social responses are impaired. In utero, electroporation demonstrates that activation of the Nrp2 gene in MCs is sufficient to instruct their circuit formation from the PV MOB to the anterior MeA.

A critical role for very long-chain fatty acid elongases in oleic acid-mediated Saccharomyces cerevisiae cytotoxicity.

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Wang, Qiao; Du, Xiuxiu; Ma, Ke; Shi, Ping; Liu, Wenbin; Sun, Jing; Peng, Min; Huang, Zhiwei

2018-03-01

Elongases FEN1/ELO2 and SUR4/ELO3 are important enzymes involved in the elongation of long-chain fatty acids (LCFAs) to very long-chain fatty acids (VLCFAs) in Saccharomyces cerevisiae. The molecular mechanism of the involvement of these elongases in lipotoxicity is unclear. In the present study, we investigated the role of VLCFA elongases in oleic acid-mediated yeast cytotoxicity. The spot test showed that yeast strains with the deletion of ELO2 or ELO3 were strikingly sensitive to oleic acid, while there was no change on the growth of strain with deleted ELO1 which was involved in the elongation of C 14 fatty acid (FA) to C 16 FA. By using GC-MS, the unsaturation index was increased in elo2△ and elo3△ mutants after treatment with oleic acid (OLA). However, the proportion of VLCFAs was increased in response to OLA in the wild-type strain. The growth inhibition of elo2△ and elo3△ could be partially rescued by two commonly used antioxidant agents N-acetyl cysteine (NAC) and Ascorbic acid (VC). The further study showed that exposure to excess OLA led to an increase in the levels of reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS), and a decline in the quantity of reduced glutathione (GSH) in both the wild type and mutant strains. However, the antioxidant enzyme activities of superoxide dismutase (SOD) and catalase (CAT) were increased in the wild type and elo1△ strains, while they were significantly decreased in the mutants of elo2△ and elo3△ after treated with excess OLA. Thus, oxidative damage mainly contributed to the cell death induced by OLA in ole2△ and ole3△. Taken together, although disruption of ELO2 or ELO3 did not affect the cellular lipid unsaturation, they altered the distribution and propotion of cellular VLCFAs, leading to the cell membrane impairment, which augmented the ability of OLA to permeabilize the plasma membrane. The data suggest that the very long-chain fatty acids elongases ELO2 and ELO3

Acoustic stimulation can induce a selective neural network response mediated by piezoelectric nanoparticles

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Rojas, Camilo; Tedesco, Mariateresa; Massobrio, Paolo; Marino, Attilio; Ciofani, Gianni; Martinoia, Sergio; Raiteri, Roberto

2018-06-01

Objective. We aim to develop a novel non-invasive or minimally invasive method for neural stimulation to be applied in the study and treatment of brain (dys)functions and neurological disorders. Approach. We investigate the electrophysiological response of in vitro neuronal networks when subjected to low-intensity pulsed acoustic stimulation, mediated by piezoelectric nanoparticles adsorbed on the neuronal membrane. Main results. We show that the presence of piezoelectric barium titanate nanoparticles induces, in a reproducible way, an increase in network activity when excited by stationary ultrasound waves in the MHz regime. Such a response can be fully recovered when switching the ultrasound pulse off, depending on the generated pressure field amplitude, whilst it is insensitive to the duration of the ultrasound pulse in the range 0.5 s–1.5 s. We demonstrate that the presence of piezoelectric nanoparticles is necessary, and when applying the same acoustic stimulation to neuronal cultures without nanoparticles or with non-piezoelectric nanoparticles with the same size distribution, no network response is observed. Significance. We believe that our results open up an extremely interesting approach when coupled with suitable functionalization strategies of the nanoparticles in order to address specific neurons and/or brain areas and applied in vivo, thus enabling remote, non-invasive, and highly selective modulation of the activity of neuronal subpopulations of the central nervous system of mammalians.

Evidence for a role of Collapsin response mediator protein-2 in signaling pathways that regulate the proliferation of non-neuronal cells

International Nuclear Information System (INIS)

Tahimic, Candice Ginn T.; Tomimatsu, Nozomi; Nishigaki, Ryuichi; Fukuhara, Akiko; Toda, Tosifusa; Kaibuchi, Kozo; Shiota, Goshi; Oshimura, Mitsuo; Kurimasa, Akihiro

2006-01-01

Collapsin response mediator protein-2 or Crmp-2 plays a critical role in the establishment of neuronal polarity. In this study, we present evidence that apart from its functions in neurodevelopment, Crmp-2 is also involved in pathways that regulate the proliferation of non-neuronal cells through its phosphorylation by regulatory proteins. We show that Crmp-2 undergoes dynamic phosphorylation changes in response to contact inhibition-induced quiescence and that hyperphosphorylation of Crmp-2 occurs in a tumor. We further suggest that de-regulation of Crmp-2 phosphorylation levels at certain amino acid residues may lead to aberrant cell proliferation and consequently, tumorigenesis

Cobaltous chloride and hypoxia inhibit aryl hydrocarbon receptor-mediated responses in breast cancer cells

International Nuclear Information System (INIS)

Khan, Shaheen; Liu Shengxi; Stoner, Matthew; Safe, Stephen

2007-01-01

The aryl hydrocarbon receptor (AhR) is expressed in estrogen receptor (ER)-positive ZR-75 breast cancer cells. Treatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces CYP1A1 protein and mRNA levels and also activates inhibitory AhR-ERα crosstalk associated with hormone-induced reporter gene expression. In ZR-75 cells grown under hypoxia, induction of these AhR-mediated responses by TCDD was significantly inhibited. This was not accompanied by decreased nuclear AhR levels or decreased interaction of the AhR complex with the CYP1A1 gene promoter as determined in a chromatin immunoprecipitation assay. Hypoxia-induced loss of Ah-responsiveness was not associated with induction of hypoxia-inducible factor-1α or other factors that sequester the AhR nuclear translocation (Arnt) protein, and overexpression of Arnt under hypoxia did not restore Ah-responsiveness. The p65 subunit of NFκB which inhibits AhR-mediated transactivation was not induced by hypoxia and was primarily cytosolic in ZR-75 cells grown under hypoxic and normoxic conditions. In ZR-75 cells maintained under hypoxic conditions for 24 h, BRCA1 (an enhancer of AhR-mediated transactivation in breast cancer cells) was significantly decreased and this contributed to loss of Ah-responsiveness. In cells grown under hypoxia for 6 h, BRCA1 was not decreased, but induction of CYP1A1 by TCDD was significantly decreased. Cotreatment of ZR-75 cells with TCDD plus the protein synthesis inhibitor cycloheximide for 6 h enhanced CYP1A1 expression in cells grown under hypoxia and normoxia. These results suggest that hypoxia rapidly induces protein(s) that inhibit Ah-responsiveness and these may be similar to constitutively expressed inhibitors of Ah-responsiveness (under normoxia) that are also inhibited by cycloheximide

Effective amino acid composition of seaweeds inducing food preference behaviors in Aplysia kurodai.

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Nagahama, Tatsumi; Fujimoto, Kiyo; Takami, Shigemi; Kinugawa, Aiko; Narusuye, Kenji

2009-07-01

Aplysia kurodai feeds on Ulva but rejects Gelidium and Pachydictyon with distinct patterned jaw movements. We previously demonstrated that these movements are induced by taste alone. Thus some chemicals may contribute to induction of these responses. We explored the amino acids composition of Ulva, Gelidium and Pachydictyon extracts used during our taste-induced physiological experiments. These solutions contained many constituents. The concentrations of six amino acids (Asp, Asn, Glu, Gln, Phe, Tau) were obviously different in the three extract solutions. We explored patterned jaw movements following application of solutions containing a pure amino acid. We statistically compared the occurrence numbers of ingestion-like and rejection-like patterned jaw movements (positive and negative values, respectively) for each amino acid. Our results suggested that L-Asn tends to induce ingestion-like responses, likely resulting in a preference of Ulva. In contrast, L-Asp tends to induce rejection-like responses, likely resulting in aversion towards Pachydictyon. In addition, we demonstrated that L-Asn and L-Asp solutions were sufficient to induce muscle activity associated with ingestion-like or rejection-like responses in the jaw muscles of a semi-intact preparation.

Bacteria-triggered systemic immunity in barley is associated with WRKY and ETHYLENE RESPONSIVE FACTORs but not with salicylic acid.

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Dey, Sanjukta; Wenig, Marion; Langen, Gregor; Sharma, Sapna; Kugler, Karl G; Knappe, Claudia; Hause, Bettina; Bichlmeier, Marlies; Babaeizad, Valiollah; Imani, Jafargholi; Janzik, Ingar; Stempfl, Thomas; Hückelhoven, Ralph; Kogel, Karl-Heinz; Mayer, Klaus F X; Vlot, A Corina

2014-12-01

Leaf-to-leaf systemic immune signaling known as systemic acquired resistance is poorly understood in monocotyledonous plants. Here, we characterize systemic immunity in barley (Hordeum vulgare) triggered after primary leaf infection with either Pseudomonas syringae pathovar japonica (Psj) or Xanthomonas translucens pathovar cerealis (Xtc). Both pathogens induced resistance in systemic, uninfected leaves against a subsequent challenge infection with Xtc. In contrast to systemic acquired resistance in Arabidopsis (Arabidopsis thaliana), systemic immunity in barley was not associated with NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 or the local or systemic accumulation of salicylic acid. Instead, we documented a moderate local but not systemic induction of abscisic acid after infection of leaves with Psj. In contrast to salicylic acid or its functional analog benzothiadiazole, local applications of the jasmonic acid methyl ester or abscisic acid triggered systemic immunity to Xtc. RNA sequencing analysis of local and systemic transcript accumulation revealed unique gene expression changes in response to both Psj and Xtc and a clear separation of local from systemic responses. The systemic response appeared relatively modest, and quantitative reverse transcription-polymerase chain reaction associated systemic immunity with the local and systemic induction of two WRKY and two ETHYLENE RESPONSIVE FACTOR (ERF)-like transcription factors. Systemic immunity against Xtc was further associated with transcriptional changes after a secondary/systemic Xtc challenge infection; these changes were dependent on the primary treatment. Taken together, bacteria-induced systemic immunity in barley may be mediated in part by WRKY and ERF-like transcription factors, possibly facilitating transcriptional reprogramming to potentiate immunity. © 2014 American Society of Plant Biologists. All Rights Reserved.

The OXI1 kinase pathway mediates Piriformospora indica-induced growth promotion in Arabidopsis.

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Iris Camehl

2011-05-01

Full Text Available Piriformospora indica is an endophytic fungus that colonizes roots of many plant species and promotes growth and resistance to certain plant pathogens. Despite its potential use in agriculture, little is known on the molecular basis of this beneficial plant-fungal interaction. In a genetic screen for plants, which do not show a P. indica- induced growth response, we isolated an Arabidopsis mutant in the OXI1 (Oxidative Signal Inducible1 gene. OXI1 has been characterized as a protein kinase which plays a role in pathogen response and is regulated by H₂O₂ and PDK1 (3-PHOSPHOINOSITIDE-DEPENDENT PROTEIN KINASE1. A genetic analysis showed that double mutants of the two closely related PDK1.1 and PDK1.2 genes are defective in the growth response to P. indica. While OXI1 and PDK1 gene expression is upregulated in P. indica-colonized roots, defense genes are downregulated, indicating that the fungus suppresses plant defense reactions. PDK1 is activated by phosphatidic acid (PA and P. indica triggers PA synthesis in Arabidopsis plants. Under beneficial co-cultivation conditions, H₂O₂ formation is even reduced by the fungus. Importantly, phospholipase D (PLDα1 or PLDδ mutants, which are impaired in PA synthesis do not show growth promotion in response to fungal infection. These data establish that the P. indica-stimulated growth response is mediated by a pathway consisting of the PLD-PDK1-OXI1 cascade.

Abscisic acid induces biosynthesis of bisbibenzyls and tolerance to UV-C in the liverwort Marchantia polymorpha.

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Kageyama, Akito; Ishizaki, Kimitsune; Kohchi, Takayuki; Matsuura, Hideyuki; Takahashi, Kosaku

2015-09-01

Environmental stresses are effective triggers for the biosynthesis of various secondary metabolites in plants, and phytohormones such as jasmonic acid and abscisic acid are known to mediate such responses in flowering plants. However, the detailed mechanism underlying the regulation of secondary metabolism in bryophytes remains unclear. In this study, the induction mechanism of secondary metabolites in the model liverwort Marchantia polymorpha was investigated. Abscisic acid (ABA) and ultraviolet irradiation (UV-C) were found to induce the biosynthesis of isoriccardin C, marchantin C, and riccardin F, which are categorized as bisbibenzyls, characteristic metabolites of liverworts. UV-C led to the significant accumulation of ABA. Overexpression of MpABI1, which encodes protein phosphatase 2C (PP2C) as a negative regulator of ABA signaling, suppressed accumulation of bisbibenzyls in response to ABA and UV-C irradiation and conferred susceptibility to UV-C irradiation. These data show that ABA plays a significant role in the induction of bisbibenzyl biosynthesis, which might confer tolerance against UV-C irradiation in M. polymorpha. Copyright © 2015 Elsevier Ltd. All rights reserved.

Polyethylene glycol-functionalized poly (Lactic Acid-co-Glycolic Acid and graphene oxide nanoparticles induce pro-inflammatory and apoptotic responses in Candida albicans-infected vaginal epithelial cells.

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R Doug Wagner

Full Text Available Mucous-penetrating nanoparticles consisting of poly lactic acid-co-glycolic acid (PLGA-polyethylene glycol (PEG could improve targeting of microbicidal drugs for sexually transmitted diseases by intravaginal inoculation. Nanoparticles can induce inflammatory responses, which may exacerbate the inflammation that occurs in the vaginal tracts of women with yeast infections. This study evaluated the effects of these drug-delivery nanoparticles on VK2(E6/E7 vaginal epithelial cell proinflammatory responses to Candida albicans yeast infections. Vaginal epithelial cell monolayers were infected with C. albicans and exposed to 100 μg/ml 49.5 nm PLGA-PEG nanospheres or 20 μg/ml 1.1 x 500 nm PEG-functionalized graphene oxide (GO-PEG sheets. The cells were assessed for changes in mRNA and protein expression of inflammation-related genes by RT-qPCR and physiological markers of cell stress using high content analysis and flow cytometry. C. albicans exposure suppressed apoptotic gene expression, but induced oxidative stress in the cells. The nanomaterials induced cytotoxicity and programmed cell death responses alone and with C. albicans. PLGA-PEG nanoparticles induced mRNA expression of apoptosis-related genes and induced poly (ADP-ribose polymerase (PARP cleavage, increased BAX/BCL2 ratios, and chromatin condensation indicative of apoptosis. They also induced autophagy, endoplasmic reticulum stress, and DNA damage. They caused the cells to excrete inflammatory recruitment molecules chemokine (C-X-C motif ligand 1 (CXCL1, interleukin-1α (IL1A, interleukin-1β (IL1B, calprotectin (S100A8, and tumor necrosis factor α (TNF. GO-PEG nanoparticles induced expression of necrosis-related genes and cytotoxicity. They reduced autophagy and endoplasmic reticulum stress, and apoptotic gene expression responses. The results show that stealth nanoparticle drug-delivery vehicles may cause intracellular damage to vaginal epithelial cells by several mechanisms and that

Salicylic acid-mediated establishment of the compatibility between Alternaria brassicicola and Brassica juncea is mitigated by abscisic acid in Sinapis alba.

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Mazumder, Mrinmoy; Das, Srirupa; Saha, Upala; Chatterjee, Madhuvanti; Bannerjee, Kaushik; Basu, Debabrata

2013-09-01

This work addresses the changes in the phytohormonal signature in the recognition of the necrotrophic fungal pathogen Alternaria brassicicola by susceptible Brassica juncea and resistant Sinapis alba. Although B. juncea, S. alba and Arabidopsis all belong to the same family, Brassicaceae, the phytohormonal response of susceptible B. juncea towards this pathogen is unique because the latter two species express non-host resistance. The differential expression of the PR1 gene and the increased level of salicylic acid (SA) indicated that an SA-mediated biotrophic mode of defence response was triggered in B. juncea upon challenge with the pathogen. Compared to B. juncea, resistant S. alba initiated enhanced abscisic acid (ABA) and jasmonic acid (JA) responses following challenge with this pathogen, as revealed by monitoring the expression of ABA-related genes along with the concentration of ABA and JA. Furthermore, these results were verified by the exogenous application of ABA on B. juncea leaves prior to challenge with A. brassicicola, which resulted in a delayed disease progression, followed by the inhibition of the pathogen-mediated increase in SA response and enhanced JA levels. Therefore, it seems that A. brassicicola is steering the defence response towards a biotrophic mode by mounting an SA response in susceptible B. juncea, whereas the enhanced ABA response of S. alba not only counteracts the SA response but also restores the necrotrophic mode of resistance by enhancing JA biosynthesis. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Saturated fatty acid palmitate induces extracellular release of histone H3: A possible mechanistic basis for high-fat diet-induced inflammation and thrombosis

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Shrestha, Chandan [Department of Systems Biology in Thromboregulation, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima (Japan); Department of Laboratory and Vascular Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima (Japan); Ito, Takashi [Department of Systems Biology in Thromboregulation, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima (Japan); Kawahara, Ko-ichi [Department of Biomedical Engineering, Osaka Institute of Technology, Osaka (Japan); Shrestha, Binita; Yamakuchi, Munekazu; Hashiguchi, Teruto [Department of Laboratory and Vascular Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima (Japan); Maruyama, Ikuro, E-mail: rinken@m3.kufm.kagoshima-u.ac.jp [Department of Systems Biology in Thromboregulation, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima (Japan)

2013-08-09

Highlights: •High-fat diet feeding and palmitate induces the release of nuclear protein histone H3. •ROS production and JNK signaling mediates the release of histone H3. •Extracellular histones induces proinflammatory and procoagulant response. -- Abstract: Chronic low-grade inflammation is a key contributor to high-fat diet (HFD)-related diseases, such as type 2 diabetes, non-alcoholic steatohepatitis, and atherosclerosis. The inflammation is characterized by infiltration of inflammatory cells, particularly macrophages, into obese adipose tissue. However, the molecular mechanisms by which a HFD induces low-grade inflammation are poorly understood. Here, we show that histone H3, a major protein component of chromatin, is released into the extracellular space when mice are fed a HFD or macrophages are stimulated with the saturated fatty acid palmitate. In a murine macrophage cell line, RAW 264.7, palmitate activated reactive oxygen species (ROS) production and JNK signaling. Inhibitors of these pathways dampened palmitate-induced histone H3 release, suggesting that the extracellular release of histone H3 was mediated, in part, through ROS and JNK signaling. Extracellular histone activated endothelial cells toexpress the adhesion molecules ICAM-1 and VCAM-1 and the procoagulant molecule tissue factor, which are known to contribute to inflammatory cell recruitment and thrombosis. These results suggest the possible contribution of extracellular histone to the pathogenesis of HFD-induced inflammation and thrombosis.

Saturated fatty acid palmitate induces extracellular release of histone H3: A possible mechanistic basis for high-fat diet-induced inflammation and thrombosis

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Shrestha, Chandan; Ito, Takashi; Kawahara, Ko-ichi; Shrestha, Binita; Yamakuchi, Munekazu; Hashiguchi, Teruto; Maruyama, Ikuro

2013-01-01

Highlights: •High-fat diet feeding and palmitate induces the release of nuclear protein histone H3. •ROS production and JNK signaling mediates the release of histone H3. •Extracellular histones induces proinflammatory and procoagulant response. -- Abstract: Chronic low-grade inflammation is a key contributor to high-fat diet (HFD)-related diseases, such as type 2 diabetes, non-alcoholic steatohepatitis, and atherosclerosis. The inflammation is characterized by infiltration of inflammatory cells, particularly macrophages, into obese adipose tissue. However, the molecular mechanisms by which a HFD induces low-grade inflammation are poorly understood. Here, we show that histone H3, a major protein component of chromatin, is released into the extracellular space when mice are fed a HFD or macrophages are stimulated with the saturated fatty acid palmitate. In a murine macrophage cell line, RAW 264.7, palmitate activated reactive oxygen species (ROS) production and JNK signaling. Inhibitors of these pathways dampened palmitate-induced histone H3 release, suggesting that the extracellular release of histone H3 was mediated, in part, through ROS and JNK signaling. Extracellular histone activated endothelial cells toexpress the adhesion molecules ICAM-1 and VCAM-1 and the procoagulant molecule tissue factor, which are known to contribute to inflammatory cell recruitment and thrombosis. These results suggest the possible contribution of extracellular histone to the pathogenesis of HFD-induced inflammation and thrombosis

Effect of α-linolenic acid on endoplasmic reticulum stress-mediated apoptosis of palmitic acid lipotoxicity in primary rat hepatocytes

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Dong Lei

2011-07-01

Full Text Available Abstract Background Hepatic inflammation and degeneration induced by lipid depositions may be the major cause of nonalcoholic fatty liver disease (NAFLD. In this study, we investigated the effects of saturated and unsaturated fatty acids (FA on apoptosis in primary rat hepatocytes. Methods The primary rat hepatocytes were treated with palmitic acid and/or α-linolenic acid in vitro. The expression of proteins associated with endoplasmic reticulum (ER stress, apoptosis, caspase-3 levels were detected after the treatment. Results The treatment with palmitic acid produced a significant increase in cell death. The unfolded protein response (UPR-associated genes CHOP, GRP78, and GRP94 were induced to higher expression levels by palmitic acid. Co-treatment with α-linolenic acid reversed the apoptotic effect and levels of all three indicators of ER stress exerted by palmitic acid. Tunicamycin, which induces ER stress produced similar effects to those obtained using palmitic acid; its effects were also reversed by α-linolenic acid. Conclusions α-Linolenic acid may provide a useful strategy to avoid the lipotoxicity of dietary palmitic acid and nutrient overload accompanied with obesity and NAFLD.

Do induced responses mediate the ecological interactions between the specialist herbivores and phytopathogens of an alpine plant?

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Röder, Gregory; Rahier, Martine; Naisbit, Russell E

2011-05-04

Plants are not passive victims of the myriad attackers that rely on them for nutrition. They have a suite of physical and chemical defences, and are even able to take advantage of the enemies of their enemies. These strategies are often only deployed upon attack, so may lead to indirect interactions between herbivores and phytopathogens. In this study we test for induced responses in wild populations of an alpine plant (Adenostyles alliariae) that possesses constitutive chemical defence (pyrrolizidine alkaloids) and specialist natural enemies (two species of leaf beetle, Oreina elongata and Oreina cacaliae, and the phytopathogenic rust Uromyces cacaliae). Plants were induced in the field using chemical elicitors of the jasmonic acid (JA) and salicylic acid (SA) pathways and monitored for one month under natural conditions. There was evidence for induced resistance, with lower probability and later incidence of attack by beetles in JA-induced plants and of rust infection in SA-induced plants. We also demonstrate ecological cross-effects, with reduced fungal attack following JA-induction, and a cost of SA-induction arising from increased beetle attack. As a result, there is the potential for negative indirect effects of the beetles on the rust, while in the field the positive indirect effect of the rust on the beetles appears to be over-ridden by direct effects on plant nutritional quality. Such interactions resulting from induced susceptibility and resistance must be considered if we are to exploit plant defences for crop protection using hormone elicitors or constitutive expression. More generally, the fact that induced defences are even found in species that possess constitutively-expressed chemical defence suggests that they may be ubiquitous in higher plants.

Do induced responses mediate the ecological interactions between the specialist herbivores and phytopathogens of an alpine plant?

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Gregory Röder

2011-05-01

Full Text Available Plants are not passive victims of the myriad attackers that rely on them for nutrition. They have a suite of physical and chemical defences, and are even able to take advantage of the enemies of their enemies. These strategies are often only deployed upon attack, so may lead to indirect interactions between herbivores and phytopathogens. In this study we test for induced responses in wild populations of an alpine plant (Adenostyles alliariae that possesses constitutive chemical defence (pyrrolizidine alkaloids and specialist natural enemies (two species of leaf beetle, Oreina elongata and Oreina cacaliae, and the phytopathogenic rust Uromyces cacaliae. Plants were induced in the field using chemical elicitors of the jasmonic acid (JA and salicylic acid (SA pathways and monitored for one month under natural conditions. There was evidence for induced resistance, with lower probability and later incidence of attack by beetles in JA-induced plants and of rust infection in SA-induced plants. We also demonstrate ecological cross-effects, with reduced fungal attack following JA-induction, and a cost of SA-induction arising from increased beetle attack. As a result, there is the potential for negative indirect effects of the beetles on the rust, while in the field the positive indirect effect of the rust on the beetles appears to be over-ridden by direct effects on plant nutritional quality. Such interactions resulting from induced susceptibility and resistance must be considered if we are to exploit plant defences for crop protection using hormone elicitors or constitutive expression. More generally, the fact that induced defences are even found in species that possess constitutively-expressed chemical defence suggests that they may be ubiquitous in higher plants.

The octadecanoid signalling pathway in plants mediates a response to ultraviolet radiation

International Nuclear Information System (INIS)

Conconi, A.; Smerdon, M.J.; Howe, G.A.; Ryan, C.A.

1996-01-01

Many plant genes that respond to environmental and developmental changes are regulated by jasmonic acid, which is derived from linolenic acid via the octadecanoid pathway. Linolenic acid is an important fatty-acid constituent of membranes in most plant species and its intracellular levels increase in response to certain signals. Here we report that irradiation of tomato leaves with ultraviolet light induces the expression of several plant defensive genes that are normally activated through the octadecanoid pathway after wounding. The response to ultraviolet light is blocked by an inhibitor of the octadecanoid pathway and it does not occur in a tomato mutant defective in this pathway. The ultraviolet irradiation maximally induces the defence genes at levels where cyclobutane pyrimidine dimer formation, an indicator of DNA damage, is less than 0.2 dimers per gene. Our evidence indicates that this plant defence response to certain wavelengths of ultraviolet radiation requires the activation of the octadecanoid defence signalling pathway. (author)

Mitochondrial proteomics of the acetic acid – induced programmed cell death response in a highly tolerant Zygosaccharomyces bailii – derived hybrid strain

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Joana F Guerreiro

2016-01-01

Full Text Available Very high concentrations of acetic acid at low pH induce programmed cell death (PCD in both the experimental model Saccharomyces cerevisiae and in Zygosaccharomyces bailii, the latter being considered the most problematic acidic food spoilage yeast due to its remarkable intrinsic resistance to this food preservative. However, while the mechanisms underlying S. cerevisiae PCD induced by acetic acid have been previously examined, the corresponding molecular players remain largely unknown in Z. bailii. Also, the reason why acetic acid concentrations known to be necrotic for S. cerevisiae induce PCD with an apoptotic phenotype in Z. bailii remains to be elucidated. In this study, a 2-DE-based expression mitochondrial proteomic analysis was explored to obtain new insights into the mechanisms involved in PCD in the Z. bailii derived hybrid strain ISA1307. This allowed the quantitative assessment of expression of protein species derived from each of the parental strains, with special emphasis on the processes taking place in the mitochondria known to play a key role in acetic acid – induced PCD. A marked decrease in the content of proteins involved in mitochondrial metabolism, in particular, in respiratory metabolism (Cor1, Rip1, Lpd1, Lat1 and Pdb1, with a concomitant increase in the abundance of proteins involved in fermentation (Pdc1, Ald4, Dld3 was registered. Other differentially expressed identified proteins also suggest the involvement of the oxidative stress response, protein translation, amino acid and nucleotide metabolism, among other processes, in the PCD response. Overall, the results strengthen the emerging concept of the importance of metabolic regulation of yeast PCD.

Genome Wide Transcriptome Analysis reveals ABA mediated response in Arabidopsis during Gold (AuCl4- treatment

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Devesh eShukla

2014-11-01

Full Text Available The unique physico-chemical properties of gold nanoparticles (AuNPs find manifold applications in diagnostics, medicine and catalysis. Chemical synthesis produces reactive AuNPs and generates hazardous by-products. Alternatively, plants can be utilized to produce AuNPs in an eco-friendly manner. To better control the biosynthesis of AuNPs, we need to first understand the detailed molecular response induced by AuCl4- In this study, we carried out global transcriptome analysis in root tissue of Arabidopsis grown for 12- hours in presence of gold solution (HAuCl4 using the novel unbiased Affymetrix exon array. Transcriptomics analysis revealed differential regulation of a total of 704 genes and 4900 exons. Of these, 492 and 212 genes were up- and downregulated, respectively. The validation of the expressed key genes, such as glutathione-S-transferases, auxin responsive genes, cytochrome P450 82C2, methyl transferases, transducin (G protein beta subunit, ERF transcription factor, ABC, and MATE transporters, was carried out through quantitative RT-PCR. These key genes demonstrated specific induction under AuCl4- treatment relative to other heavy metals, suggesting a unique plant-gold interaction. GO enrichment analysis reveals the upregulation of processes like oxidative stress, glutathione binding, metal binding, transport, and plant hormonal responses. Changes predicted in biochemical pathways indicated major modulation in glutathione mediated detoxification, flavones and derivatives, and plant hormone biosynthesis. Motif search analysis identified a highly significant enriched motif, ACGT, which is an abscisic acid responsive core element (ABRE, suggesting the possibility of ABA- mediated signaling. Identification of abscisic acid response element (ABRE points to the operation of a predominant signaling mechanism in response to AuCl4- exposure. Overall, this study presents a useful picture of plant-gold interaction with an identification of

Auxin-dependent compositional change in Mediator in ARF7- and ARF19-mediated transcription.

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Ito, Jun; Fukaki, Hidehiro; Onoda, Makoto; Li, Lin; Li, Chuanyou; Tasaka, Masao; Furutani, Masahiko

2016-06-07

Mediator is a multiprotein complex that integrates the signals from transcription factors binding to the promoter and transmits them to achieve gene transcription. The subunits of Mediator complex reside in four modules: the head, middle, tail, and dissociable CDK8 kinase module (CKM). The head, middle, and tail modules form the core Mediator complex, and the association of CKM can modify the function of Mediator in transcription. Here, we show genetic and biochemical evidence that CKM-associated Mediator transmits auxin-dependent transcriptional repression in lateral root (LR) formation. The AUXIN/INDOLE 3-ACETIC ACID 14 (Aux/IAA14) transcriptional repressor inhibits the transcriptional activity of its binding partners AUXIN RESPONSE FACTOR 7 (ARF7) and ARF19 by making a complex with the CKM-associated Mediator. In addition, TOPLESS (TPL), a transcriptional corepressor, forms a bridge between IAA14 and the CKM component MED13 through the physical interaction. ChIP assays show that auxin induces the dissociation of MED13 but not the tail module component MED25 from the ARF7 binding region upstream of its target gene. These findings indicate that auxin-induced degradation of IAA14 changes the module composition of Mediator interacting with ARF7 and ARF19 in the upstream region of their target genes involved in LR formation. We suggest that this regulation leads to a quick switch of signal transmission from ARFs to target gene expression in response to auxin.

Non-pathogenic rhizobacteria interfere with the attraction of parasitoids to aphid-induced plant volatiles via jasmonic acid signalling.

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Pineda, Ana; Soler, Roxina; Weldegergis, Berhane T; Shimwela, Mpoki M; VAN Loon, Joop J A; Dicke, Marcel

2013-02-01

Beneficial soil-borne microbes, such as mycorrhizal fungi or rhizobacteria, can affect the interactions of plants with aboveground insects at several trophic levels. While the mechanisms of interactions with herbivorous insects, that is, the second trophic level, are starting to be understood, it remains unknown how plants mediate the interactions between soil microbes and carnivorous insects, that is, the third trophic level. Using Arabidopsis thaliana Col-0 and the aphid Myzus persicae, we evaluate here the underlying mechanisms involved in the plant-mediated interaction between the non-pathogenic rhizobacterium Pseudomonas fluorescens and the parasitoid Diaeretiella rapae, by combining ecological, chemical and molecular approaches. Rhizobacterial colonization modifies the composition of the blend of herbivore-induced plant volatiles. The volatile blend from rhizobacteria-treated aphid-infested plants is less attractive to an aphid parasitoid, in terms of both olfactory preference behaviour and oviposition, than the volatile blend from aphid-infested plants without rhizobacteria. Importantly, the effect of rhizobacteria on both the emission of herbivore-induced volatiles and parasitoid response to aphid-infested plants is lost in an Arabidopsis mutant (aos/dde2-2) that is impaired in jasmonic acid production. By modifying the blend of herbivore-induced plant volatiles that depend on the jasmonic acid-signalling pathway, root-colonizing microbes interfere with the attraction of parasitoids of leaf herbivores. © 2012 Blackwell Publishing Ltd.

Role of Reactive Oxygen Species and Nitric Oxide in Mediating Chemotherapeutic Drug Induced Bystander Response in Human Cancer Cells Exposed In-Vitro

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Chinnadurai, Mani; Rao, Bhavna S; Deepika, Ramasamy; Paul, Solomon F.D.; Venkatachalam, Perumal

2012-01-01

Background The intention of cancer chemotherapy is to control the growth of cancer cells using chemical agents. However, the occurrence of second malignancies has raised concerns, leading to re-evaluation of the current strategy in use for chemotherapeutic agents. Although the mechanisms involved in second malignancy remain ambiguous, therapeutic-agent-induced non-DNA targeted effects like bystander response and genomic instability cannot be eliminated completely. Hence, Bleomycin (BLM) and Neocarzinostatin (NCS), chemotherapeutic drugs with a mode of action similar to ionizing radiation, were used to study the mechanism of bystander response in human cancer cells (A549, CCRF-CEM and HL-60) by employing co-culture methodology. Methods Bystander effect was quantified using micronucleus (MN) assay and in-situ immunofluorescence(γH2AX assay).The role of reactive oxygen species (ROS) and nitric oxide (NO) in mediating the bystander response was explored by pre-treating bystander cells with dimethylsulphoxide (DMSO) and C-PTIO respectively. Results Bystander response was observed only in CCRF-CEM and A549 cells (P bystander response on treatment with DMSO, suggests that ROS has a more significant role in mediating the bystander response.Since the possibility of the ROS and NO in mediating these bystander effect was confirmed, mechanistic control of these signaling molecules could either reduce radiation damage and potential carcinogenicity of normal tissues (by reducing bystander signaling) or maximize cell sterilization during chemotherapy (by amplifying bystander responses in tumors). PMID:29147282

The plastidial retrograde signal methyl erythritol cyclopyrophosphate is a regulator of salicylic acid and jasmonic acid crosstalk.

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Lemos, Mark; Xiao, Yanmei; Bjornson, Marta; Wang, Jin-Zheng; Hicks, Derrick; Souza, Amancio de; Wang, Chang-Quan; Yang, Panyu; Ma, Shisong; Dinesh-Kumar, Savithramma; Dehesh, Katayoon

2016-03-01

The exquisite harmony between hormones and their corresponding signaling pathways is central to prioritizing plant responses to simultaneous and/or successive environmental trepidations. The crosstalk between jasmonic acid (JA) and salicylic acid (SA) is an established effective mechanism that optimizes and tailors plant adaptive responses. However, the underlying regulatory modules of this crosstalk are largely unknown. Global transcriptomic analyses of mutant plants (ceh1) with elevated levels of the stress-induced plastidial retrograde signaling metabolite 2-C-methyl-D-erythritol cyclopyrophosphate (MEcPP) revealed robustly induced JA marker genes, expected to be suppressed by the presence of constitutively high SA levels in the mutant background. Analyses of a range of genotypes with varying SA and MEcPP levels established the selective role of MEcPP-mediated signal(s) in induction of JA-responsive genes in the presence of elevated SA. Metabolic profiling revealed the presence of high levels of the JA precursor 12-oxo-phytodienoic acid (OPDA), but near wild type levels of JA in the ceh1 mutant plants. Analyses of coronatine-insensitive 1 (coi1)/ceh1 double mutant plants confirmed that the MEcPP-mediated induction is JA receptor COI1 dependent, potentially through elevated OPDA. These findings identify MEcPP as a previously unrecognized central regulatory module that induces JA-responsive genes in the presence of high SA, thereby staging a multifaceted plant response within the environmental context. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Critical role of RanBP2-mediated SUMOylation of Small Heterodimer Partner in maintaining bile acid homeostasis

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Kim, Dong-Hyun; Kwon, Sanghoon; Byun, Sangwon; Xiao, Zhen; Park, Sean; Wu, Shwu-Yuan; Chiang, Cheng-Ming; Kemper, Byron; Kemper, Jongsook Kim

2016-01-01

Bile acids (BAs) are recently recognized signalling molecules that profoundly affect metabolism. Because of detergent-like toxicity, BA levels must be tightly regulated. An orphan nuclear receptor, Small Heterodimer Partner (SHP), plays a key role in this regulation, but how SHP senses the BA signal for feedback transcriptional responses is not clearly understood. We show an unexpected function of a nucleoporin, RanBP2, in maintaining BA homoeostasis through SUMOylation of SHP. Upon BA signalling, RanBP2 co-localizes with SHP at the nuclear envelope region and mediates SUMO2 modification at K68, which facilitates nuclear transport of SHP and its interaction with repressive histone modifiers to inhibit BA synthetic genes. Mice expressing a SUMO-defective K68R SHP mutant have increased liver BA levels, and upon BA- or drug-induced biliary insults, these mice exhibit exacerbated cholestatic pathologies. These results demonstrate a function of RanBP2-mediated SUMOylation of SHP in maintaining BA homoeostasis and protecting from the BA hepatotoxicity. PMID:27412403

Oral 2-hydroxyoleic acid inhibits reflex hypersensitivity and open-field-induced anxiety after spared nerve injury.

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Avila-Martin, G; Galan-Arriero, I; Ferrer-Donato, A; Busquets, X; Gomez-Soriano, J; Escribá, P V; Taylor, J

2015-01-01

Recently, fatty acids have been shown to modulate sensory function in animal models of neuropathic pain. In this study, the antinociceptive effect of 2-hydroxyoleic acid (2-OHOA) was assessed following spared nerve injury (SNI) with reflex and cerebrally mediated behavioural responses. Initial antinociceptive behavioural screening of daily administration of 2-OHOA (400 mg/kg, p.o.) was assessed in Wistar rats by measuring hindlimb reflex hypersensitivity to von Frey and thermal plate stimulation up to 7 days after SNI, while its modulatory effect on lumbar spinal dorsal horn microglia reactivity was assessed with OX-42 immunohistochemistry. In vitro the effect of 2-OHOA (120 μM) on cyclooxygenase protein expression (COX-2/COX-1 ratio) in lipopolysaccharide-activated macrophage cells was tested with Western blot analysis. Finally, the effects of 2-OHOA treatment on the place escape aversion paradigm (PEAP) and the open-field-induced anxiety test were tested at 21 days following nerve injury compared with vehicle-treated sham and pregabalin-SNI (30 mg/kg, p.o.) control groups. Oral 2-OHOA significantly reduced ipsilateral mechanical and thermal hypersensitivity up to 7 days after SNI. Additionally 2-OHOA decreased the COX-2/COX-1 ratio in lipopolysaccharide-activated macrophage cells and OX-42 expression within the ipsilateral lumbar spinal dorsal horn 7 days after SNI. 2-OHOA significantly restored inner-zone exploration in the open-field test compared with the vehicle-treated sham group at 21 days after SNI. Oral administration of the modified omega 9 fatty acid, 2-OHOA, mediates antinociception and prevents open-field-induced anxiety in the SNI model in Wistar rats, which is mediated by an inhibition of spinal dorsal horn microglia activation. © 2014 European Pain Federation - EFIC®

The key role of miR-21-regulated SOD2 in the medium-mediated bystander responses in human fibroblasts induced by α-irradiated keratinocytes

International Nuclear Information System (INIS)

Tian, Wenqian; Yin, Xiaoming; Wang, Longxiao; Wang, Jingdong; Zhu, Wei; Cao, Jianping; Yang, Hongying

2015-01-01

Highlights: • After co-culture with α-irradiated HaCaT cells, WS1 cells displayed oxidative stress and DNA damage. • Increased miR-21 expression in bystander cells was critical to the occurrence of RIBEs. • SOD2 of bystander cells played an important role in bystander responses. • miR-21 mediated bystander effects through its regulation on SOD2. - Abstract: Radiation-induced bystander effect (RIBE) is well accepted in the radiation research field by now, but the underlying molecular mechanisms for better understanding this phenomenon caused by intercellular communication and intracellular signal transduction are still incomplete. Although our previous study has demonstrated an important role of miR-21 of unirradiated bystander cells in RIBEs, the direct evidence for the hypothesis that RIBE is epigenetically regulated is still limited and how miR-21 mediates RIBEs is unknown. Reactive oxygen species (ROS) have been demonstrated to be involved in RIBEs, however, the roles of anti-oxidative stress system of cells in RIBEs are unclear. Using transwell insert co-culture system, we investigated medium-mediated bystander responses in WS1 human fibroblasts after co-culture with HaCaT keratinocytes traversed by α-particles. Results showed that the ROS levels in unirradiated bystander WS1 cells were significantly elevated after 30 min of co-culture, and 53BP1 foci, a surrogate marker of DNA damage, were obviously induced after 3 h of co-culture. This indicates the occurrence of oxidative stress and DNA damage in bystander WS1 cells after co-culture with irradiated keratinocytes. Furthermore, the expression of miR-21 was increased in bystander WS1 cells, downregulation of miR-21 eliminated the bystander responses, overexpression of miR-21 alone could induce bystander-like oxidative stress and DNA damage in WS1 cells. These data indicate an important mediating role of miR-21 in RIBEs. In addition, MnSOD or SOD2 in WS1 cells was involved in the bystander effects

The key role of miR-21-regulated SOD2 in the medium-mediated bystander responses in human fibroblasts induced by α-irradiated keratinocytes

Energy Technology Data Exchange (ETDEWEB)

Tian, Wenqian; Yin, Xiaoming; Wang, Longxiao; Wang, Jingdong; Zhu, Wei; Cao, Jianping [School of Radiation Medicine and Protection, Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 199 Renai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123 (China); Yang, Hongying, E-mail: yanghongying@suda.edu.cn [School of Radiation Medicine and Protection, Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 199 Renai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123 (China); Institute of Radiotherapy & Oncology, Soochow University (China)

2015-10-15

Highlights: • After co-culture with α-irradiated HaCaT cells, WS1 cells displayed oxidative stress and DNA damage. • Increased miR-21 expression in bystander cells was critical to the occurrence of RIBEs. • SOD2 of bystander cells played an important role in bystander responses. • miR-21 mediated bystander effects through its regulation on SOD2. - Abstract: Radiation-induced bystander effect (RIBE) is well accepted in the radiation research field by now, but the underlying molecular mechanisms for better understanding this phenomenon caused by intercellular communication and intracellular signal transduction are still incomplete. Although our previous study has demonstrated an important role of miR-21 of unirradiated bystander cells in RIBEs, the direct evidence for the hypothesis that RIBE is epigenetically regulated is still limited and how miR-21 mediates RIBEs is unknown. Reactive oxygen species (ROS) have been demonstrated to be involved in RIBEs, however, the roles of anti-oxidative stress system of cells in RIBEs are unclear. Using transwell insert co-culture system, we investigated medium-mediated bystander responses in WS1 human fibroblasts after co-culture with HaCaT keratinocytes traversed by α-particles. Results showed that the ROS levels in unirradiated bystander WS1 cells were significantly elevated after 30 min of co-culture, and 53BP1 foci, a surrogate marker of DNA damage, were obviously induced after 3 h of co-culture. This indicates the occurrence of oxidative stress and DNA damage in bystander WS1 cells after co-culture with irradiated keratinocytes. Furthermore, the expression of miR-21 was increased in bystander WS1 cells, downregulation of miR-21 eliminated the bystander responses, overexpression of miR-21 alone could induce bystander-like oxidative stress and DNA damage in WS1 cells. These data indicate an important mediating role of miR-21 in RIBEs. In addition, MnSOD or SOD2 in WS1 cells was involved in the bystander effects

Jasmonic acid carboxyl methyltransferase regulates development and herbivory-induced defense response in rice.

Science.gov (United States)

Qi, Jinfeng; Li, Jiancai; Han, Xiu; Li, Ran; Wu, Jianqiang; Yu, Haixin; Hu, Lingfei; Xiao, Yutao; Lu, Jing; Lou, Yonggen

2016-06-01

Jasmonic acid (JA) and related metabolites play a key role in plant defense and growth. JA carboxyl methyltransferase (JMT) may be involved in plant defense and development by methylating JA to methyl jasmonate (MeJA) and thus influencing the concentrations of JA and related metabolites. However, no JMT gene has been well characterized in monocotyledon defense and development at the molecular level. After we cloned a rice JMT gene, OsJMT1, whose encoding protein was localized in the cytosol, we found that the recombinant OsJMT1 protein catalyzed JA to MeJA. OsJMT1 is up-regulated in response to infestation with the brown planthopper (BPH; Nilaparvata lugens). Plants in which OsJMT1 had been overexpressed (oe-JMT plants) showed reduced height and yield. These oe-JMT plants also exhibited increased MeJA levels but reduced levels of herbivore-induced JA and jasmonoyl-isoleucine (JA-Ile). The oe-JMT plants were more attractive to BPH female adults but showed increased resistance to BPH nymphs, probably owing to the different responses of BPH female adults and nymphs to the changes in levels of H2 O2 and MeJA in oe-JMT plants. These results indicate that OsJMT1, by altering levels of JA and related metabolites, plays a role in regulating plant development and herbivore-induced defense responses in rice. © 2015 Institute of Botany, Chinese Academy of Sciences.

ABFs, a family of ABA-responsive element binding factors.

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Choi, H; Hong, J; Ha, J; Kang, J; Kim, S Y

2000-01-21

Abscisic acid (ABA) plays an important role in environmental stress responses of higher plants during vegetative growth. One of the ABA-mediated responses is the induced expression of a large number of genes, which is mediated by cis-regulatory elements known as abscisic acid-responsive elements (ABREs). Although a number of ABRE binding transcription factors have been known, they are not specifically from vegetative tissues under induced conditions. Considering the tissue specificity of ABA signaling pathways, factors mediating ABA-dependent stress responses during vegetative growth phase may thus have been unidentified so far. Here, we report a family of ABRE binding factors isolated from young Arabidopsis plants under stress conditions. The factors, isolated by a yeast one-hybrid system using a prototypical ABRE and named as ABFs (ABRE binding factors) belong to a distinct subfamily of bZIP proteins. Binding site selection assay performed with one ABF showed that its preferred binding site is the strong ABRE, CACGTGGC. ABFs can transactivate an ABRE-containing reporter gene in yeast. Expression of ABFs is induced by ABA and various stress treatments, whereas their induction patterns are different from one another. Thus, a new family of ABRE binding factors indeed exists that have the potential to activate a large number of ABA/stress-responsive genes in Arabidopsis.

Blue light potentiates neurogenesis induced by retinoic acid-loaded responsive nanoparticles.

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Santos, Tiago; Ferreira, Raquel; Quartin, Emanuel; Boto, Carlos; Saraiva, Cláudia; Bragança, José; Peça, João; Rodrigues, Cecília; Ferreira, Lino; Bernardino, Liliana

2017-09-01

Neurogenic niches constitute a powerful endogenous source of new neurons that can be used for brain repair strategies. Neuronal differentiation of these cells can be regulated by molecules such as retinoic acid (RA) or by mild levels of reactive oxygen species (ROS) that are also known to upregulate RA receptor alpha (RARα) levels. Data showed that neural stem cells from the subventricular zone (SVZ) exposed to blue light (405nm laser) transiently induced NADPH oxidase-dependent ROS, resulting in β-catenin activation and neuronal differentiation, and increased RARα levels. Additionally, the same blue light stimulation was capable of triggering the release of RA from light-responsive nanoparticles (LR-NP). The synergy between blue light and LR-NP led to amplified neurogenesis both in vitro and in vivo, while offering a temporal and spatial control of RA release. In conclusion, this combinatory treatment offers great advantages to potentiate neuronal differentiation, and provides an innovative and efficient application for brain regenerative therapies. Controlling the differentiation of stem cells would support the development of promising brain regenerative therapies. Blue light transiently increased reactive oxygen species, resulting in neuronal differentiation and increased retinoic acid receptor (RARα) levels. Additionally, the same blue light stimulation was capable of triggering the release of RA from light-responsive nanoparticles (LR-NP). The synergy between blue light and LR-NP led to amplified neurogenesis, while offering a temporal and spatial control of RA release. In this sense, our approach relying on the modulation of endogenous stem cells for the generation of new neurons may support the development of novel clinical therapies. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Pb-induced responses in Zygophyllum fabago plants are organ-dependent and modulated by salicylic acid.

Science.gov (United States)

López-Orenes, Antonio; Martínez-Pérez, Ascensión; Calderón, Antonio A; Ferrer, María A

2014-11-01

Zygophyllum fabago is a promising species for restoring heavy metal (HM) polluted soils, although the mechanisms involved in HM tolerance in this non-model plant remain largely unknown. This paper analyses the extent to which redox-active compounds and enzymatic antioxidants in roots, stems and leaves are responsible for Pb tolerance in a metallicolous ecotype of Z. fabago and the possible influence of salicylic acid (SA) pretreatment (24 h, 0.5 mM SA) in the response to Pb stress. SA pretreatment reduced both the accumulation of Pb in roots and even more so the concentration of Pb in aerial parts of the plants, although a similar drop in the content of chlorophylls and in the maximum quantum yield of photosystem II was observed in both Pb- and SA-Pb-treated plants. Pb increased the endogenous free SA levels in all organs and this response was enhanced in root tissues upon SA pretreatment. Generally, Pb induced a reduction in catalase, ascorbate peroxidase and glutathione reductase specific activities, whereas dehydroascorbate reductase was increased in all organs of control plants. SA pretreatment enhanced the Pb-induced H2O2 accumulation in roots by up-regulating Fe-superoxide dismutase isoenzymes. Under Pb stress, the GSH redox ratio remained highly reduced in all organs while the ascorbic acid redox ratio dropped in leaf tissues where a rise in lipid peroxidation products and electrolyte leakage was observed. Finally, an organ-dependent accumulation of proline and β-carboline alkaloids was found, suggesting these nitrogen-redox-active compounds could play a role in the adaptation strategies of this species to Pb stress. Copyright © 2014. Published by Elsevier Masson SAS.

Protective effect of Bauhinia tomentosa on acetic acid induced ulcerative colitis by regulating antioxidant and inflammatory mediators.

Science.gov (United States)

Kannan, Narayanan; Guruvayoorappan, Chandrasekharan

2013-05-01

Inflammatory bowel diseases (IBD), including Crohn's disease and Ulcerative colitis (UC), are life-long and recurrent disorders of the gastrointestinal tract with unknown etiology. The present study is designed to evaluate the ameliorative effect of Bauhinia tomentosa during ulcerative colitis (UC). Three groups of animals (n=6) were treated with B. tomentosa (5, 10, 20 mg/kg B.wt respectively) for 5 consecutive days before induction of UC. UC was induced by intracolonic injection of 3% acetic acid. The colonic mucosal injury was assessed by macroscopic scoring and histological examination. Furthermore, the mucosal content of lipid peroxidation (LPO), reduced glutathione (GSH), nitric oxide (NO), glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity confirms that B. tomentosa could significantly inhibit colitis in a dose dependent manner. The myeloperoxidase (MPO), tumor necrosis factor (TNF-α), inducible nitric oxide synthase (iNOS) expression studies and lactate dehydrogenase (LDH) assay also supported that B. tomentosa could significantly inhibit experimental colitis. The effect was comparable to the standard drug sulfasalazine. Colonic mucosal injury parallels with the result of histological and biochemical evaluations. The extracts obtained from B. tomentosa possess active substances, which exert marked protective effects in acute experimental colitis, possibly by regulating the antioxidant and inflammatory mediators. Copyright © 2013 Elsevier B.V. All rights reserved.

Ceramide Production Mediates Aldosterone-Induced Human Umbilical Vein Endothelial Cell (HUVEC Damages.

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Yumei Zhang

Full Text Available Here, we studied the underlying mechanism of aldosterone (Aldo-induced vascular endothelial cell damages by focusing on ceramide. We confirmed that Aldo (at nmol/L inhibited human umbilical vein endothelial cells (HUVEC survival, and induced considerable cell apoptosis. We propose that ceramide (mainly C18 production might be responsible for Aldo-mediated damages in HUVECs. Sphingosine-1-phosphate (S1P, an anti-ceramide lipid, attenuated Aldo-induced ceramide production and following HUVEC damages. On the other hand, the glucosylceramide synthase (GCS inhibitor PDMP or the ceramide (C6 potentiated Aldo-induced HUVEC apoptosis. Eplerenone, a mineralocorticoid receptor (MR antagonist, almost completely blocked Aldo-induced C18 ceramide production and HUVEC damages. Molecularly, ceramide synthase 1 (CerS-1 is required for C18 ceramide production by Aldo. Knockdown of CerS-1 by targeted-shRNA inhibited Aldo-induced C18 ceramide production, and protected HUVECs from Aldo. Reversely, CerS-1 overexpression facilitated Aldo-induced C18 ceramide production, and potentiated HUVEC damages. Together, these results suggest that C18 ceramide production mediates Aldo-mediated HUVEC damages. MR and CerS-1 could be the two signaling molecule regulating C18 ceramide production by Aldo.

Hepatic uptake of conjugated bile acids is mediated by both sodium taurocholate cotransporting polypeptide and organic anion transporting polypeptides and modulated by intestinal sensing of plasma bile acid levels in mice.

Science.gov (United States)

Slijepcevic, Davor; Roscam Abbing, Reinout L P; Katafuchi, Takeshi; Blank, Antje; Donkers, Joanne M; van Hoppe, Stéphanie; de Waart, Dirk R; Tolenaars, Dagmar; van der Meer, Jonathan H M; Wildenberg, Manon; Beuers, Ulrich; Oude Elferink, Ronald P J; Schinkel, Alfred H; van de Graaf, Stan F J

2017-11-01

The Na + -taurocholate cotransporting polypeptide (NTCP/SLC10A1) is believed to be pivotal for hepatic uptake of conjugated bile acids. However, plasma bile acid levels are normal in a subset of NTCP knockout mice and in mice treated with myrcludex B, a specific NTCP inhibitor. Here, we elucidated which transport proteins mediate the hepatic uptake of conjugated bile acids and demonstrated intestinal sensing of elevated bile acid levels in plasma in mice. Mice or healthy volunteers were treated with myrcludex B. Hepatic bile acid uptake kinetics were determined in wild-type (WT), organic anion transporting polypeptide (OATP) knockout mice (lacking Slco1a/1b isoforms), and human OATP1B1-transgenic mice. Effects of fibroblast growth factor 19 (FGF19) on hepatic transporter mRNA levels were assessed in rat hepatoma cells and in mice by peptide injection or adeno-associated virus-mediated overexpression. NTCP inhibition using myrcludex B had only moderate effects on bile acid kinetics in WT mice, but completely inhibited active transport of conjugated bile acid species in OATP knockout mice. Cholesterol 7α-hydroxylase Cyp7a1 expression was strongly down-regulated upon prolonged inhibition of hepatic uptake of conjugated bile acids. Fgf15 (mouse counterpart of FGF19) expression was induced in hypercholanemic OATP and NTCP knockout mice, as well as in myrcludex B-treated cholestatic mice, whereas plasma FGF19 was not induced in humans treated with myrcludex B. Fgf15/FGF19 expression was induced in polarized human enterocyte-models and mouse organoids by basolateral incubation with a high concentration (1 mM) of conjugated bile acids. NTCP and OATPs contribute to hepatic uptake of conjugated bile acids in mice, whereas the predominant uptake in humans is NTCP mediated. Enterocytes sense highly elevated levels of (conjugated) bile acids in the systemic circulation to induce FGF15/19, which modulates hepatic bile acid synthesis and uptake. (Hepatology 2017;66:1631-1643). �

The role of the arachidonic acid cascade in the species-specific X-ray-induced inflammation of the rabbit eye

International Nuclear Information System (INIS)

Bito, L.Z.; Klein, E.M.

1982-01-01

To identify the mediator(s) of the apparently species-specific X-ray-induced inflammation of the rabbit eye, inhibitors of the synthesis and/or release of known or putative mediators of ocular inflammation were administered prior to irradiation. The X-ray-induced ocular inflammation, particularly the rise in intraocular pressure, was found to be inhibited by intravenous pretreatment of rabbits with flurbiprofen, indomethacin, or imidazole (1, 10, and 100 mg/kg i.v., respectively), or by combined intravitreal and topical administration of flurbiprofen. Systemic, intravitreal, and/or topical pretreatment with prednisolone or disodium cromoglycate or the retrobulbar injection of ethyl alcohol or capsaicin failed to block the inflammatory response, whereas vitamin E apparently exerted some protective effect. These findings show that the X-ray-induced inflammation of the rabbit eye is mediated, at least in part, by prostaglandins (PGs) and/or related autacoids. In addition, these results suggest that the unique sensitivity of the rabbit eye to X-ray-induced inflammation is due either to the presence in this species of a unique or uniquely effective triggering mechanism for the release of PG precursors or to the greater sensitivity of this species to the ocular inflammatory effects of PGs. Thus the rabbit eye may provide a unique model for studying some aspects of arachidonic acid release or ocular PG effects, but extreme caution must be exercised in generalizing such findings to other species

Soybean Aphid Infestation Induces Changes in Fatty Acid Metabolism in Soybean.

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Charles Kanobe

Full Text Available The soybean aphid (Aphis glycines Matsumura is one of the most important insect pests of soybeans in the North-central region of the US. It has been hypothesized that aphids avoid effective defenses by inhibition of jasmonate-regulated plant responses. Given the role fatty acids play in jasmonate-induced plant defenses, we analyzed the fatty acid profile of soybean leaves and seeds from aphid-infested plants. Aphid infestation reduced levels of polyunsaturated fatty acids in leaves with a concomitant increase in palmitic acid. In seeds, a reduction in polyunsaturated fatty acids was associated with an increase in stearic acid and oleic acid. Soybean plants challenged with the brown stem rot fungus or with soybean cyst nematodes did not present changes in fatty acid levels in leaves or seeds, indicating that the changes induced by aphids are not a general response to pests. One of the polyunsaturated fatty acids, linolenic acid, is the precursor of jasmonate; thus, these changes in fatty acid metabolism may be examples of "metabolic hijacking" by the aphid to avoid the induction of effective defenses. Based on the changes in fatty acid levels observed in seeds and leaves, we hypothesize that aphids potentially induce interference in the fatty acid desaturation pathway, likely reducing FAD2 and FAD6 activity that leads to a reduction in polyunsaturated fatty acids. Our data support the idea that aphids block jasmonate-dependent defenses by reduction of the hormone precursor.

The obesity-induced transcriptional regulator TRIP-Br2 mediates visceral fat endoplasmic reticulum stress-induced inflammation.

Science.gov (United States)

Qiang, Guifen; Kong, Hyerim Whang; Fang, Difeng; McCann, Maximilian; Yang, Xiuying; Du, Guanhua; Blüher, Matthias; Zhu, Jinfang; Liew, Chong Wee

2016-04-25

The intimate link between location of fat accumulation and metabolic disease risk and depot-specific differences is well established, but how these differences between depots are regulated at the molecular level remains largely unclear. Here we show that TRIP-Br2 mediates endoplasmic reticulum (ER) stress-induced inflammatory responses in visceral fat. Using in vitro, ex vivo and in vivo approaches, we demonstrate that obesity-induced circulating factors upregulate TRIP-Br2 specifically in visceral fat via the ER stress pathway. We find that ablation of TRIP-Br2 ameliorates both chemical and physiological ER stress-induced inflammatory and acute phase response in adipocytes, leading to lower circulating levels of inflammatory cytokines. Using promoter assays, as well as molecular and pharmacological experiments, we show that the transcription factor GATA3 is responsible for the ER stress-induced TRIP-Br2 expression in visceral fat. Taken together, our study identifies molecular regulators of inflammatory response in visceral fat that-given that these pathways are conserved in humans-might serve as potential therapeutic targets in obesity.

A novel bZIP gene from Tamarix hispida mediates physiological responses to salt stress in tobacco plants.

Science.gov (United States)

Wang, Yucheng; Gao, Caiqiu; Liang, Yenan; Wang, Chao; Yang, Chuanping; Liu, Guifeng

2010-02-15

Basic leucine zipper proteins (bZIPs) are transcription factors that bind abscisic acid (ABA)-responsive elements (ABREs) and enable plants to withstand adverse environmental conditions. In the present study, a novel bZIP gene, ThbZIP1 was cloned from Tamarix hispida. Expression studies in T. hispida showed differential regulation of ThbZIP1 in response to treatment with NaCl, polyethylene glycol (PEG) 6000, NaHCO(3), and CdCl(2), suggesting that ThbZIP1 is involved in abiotic stress responses. To identify the physiological responses mediated by ThbZIP1, transgenic tobacco plants overexpressing exogenous ThbZIP1 were generated. Various physiological parameters related to salt stress were measured and compared between transgenic and wild type (WT) plants. Our results indicate that overexpression of ThbZIP1 can enhance the activity of both peroxidase (POD) and superoxide dismutase (SOD), and increase the content of soluble sugars and soluble proteins under salt stress conditions. These results suggest that ThbZIP1 contributes to salt tolerance by mediating signaling through multiple physiological pathways. Furthermore, ThbZIP1 confers stress tolerance to plants by enhancing reactive oxygen species (ROS) scavenging, facilitating the accumulation of compatible osmolytes, and inducing and/or enhancing the biosynthesis of soluble proteins. Copyright 2009 Elsevier GmbH. All rights reserved.

The key role of miR-21-regulated SOD2 in the medium-mediated bystander responses in human fibroblasts induced by α-irradiated keratinocytes.

Science.gov (United States)

Tian, Wenqian; Yin, Xiaoming; Wang, Longxiao; Wang, Jingdong; Zhu, Wei; Cao, Jianping; Yang, Hongying

2015-10-01

Radiation-induced bystander effect (RIBE) is well accepted in the radiation research field by now, but the underlying molecular mechanisms for better understanding this phenomenon caused by intercellular communication and intracellular signal transduction are still incomplete. Although our previous study has demonstrated an important role of miR-21 of unirradiated bystander cells in RIBEs, the direct evidence for the hypothesis that RIBE is epigenetically regulated is still limited and how miR-21 mediates RIBEs is unknown. Reactive oxygen species (ROS) have been demonstrated to be involved in RIBEs, however, the roles of anti-oxidative stress system of cells in RIBEs are unclear. Using transwell insert co-culture system, we investigated medium-mediated bystander responses in WS1 human fibroblasts after co-culture with HaCaT keratinocytes traversed by α-particles. Results showed that the ROS levels in unirradiated bystander WS1 cells were significantly elevated after 30min of co-culture, and 53BP1 foci, a surrogate marker of DNA damage, were obviously induced after 3h of co-culture. This indicates the occurrence of oxidative stress and DNA damage in bystander WS1 cells after co-culture with irradiated keratinocytes. Furthermore, the expression of miR-21 was increased in bystander WS1 cells, downregulation of miR-21 eliminated the bystander responses, overexpression of miR-21 alone could induce bystander-like oxidative stress and DNA damage in WS1 cells. These data indicate an important mediating role of miR-21 in RIBEs. In addition, MnSOD or SOD2 in WS1 cells was involved in the bystander effects, overexpression of SOD2 abolished the bystander oxidative stress and DNA damage, indicating that SOD2 was critical to the induction of RIBEs. Moreover, we found that miR-21 regulated SOD2, suggesting that miR-21 might mediate bystander responses through its regulation on SOD2. In conclusion, this study revealed a profound role of miR-21-regulated SOD2 of unirradiated WS1

Radiation-induced gene responses

International Nuclear Information System (INIS)

Woloschak, G.E.; Paunesku, T.; Shearin-Jones, P.; Oryhon, J.

1996-01-01

In the process of identifying genes that are differentially regulated in cells exposed to ultraviolet radiation (UV), we identified a transcript that was repressed following the exposure of cells to a combination of UV and salicylate, a known inhibitor of NF-kappaB. Sequencing this band determined that it has identify to lactate dehydrogenase, and Northern blots confirmed the initial expression pattern. Analysis of the sequence of the LDH 5' region established the presence of NF-kappaB, Sp1, and two Ap-2 elements; two partial AP- 1; one partial RE, and two halves of E-UV elements were also found. Electromobility shift assays were then performed for the AP-1, NF- kappaB, and E-UV elements. These experiments revealed that binding to NF-kappaB was induced by UV but repressed with salicylic acid; UV did not affect AP-1 binding, but salicylic acid inhibited it alone or following UV exposure; and E-UV binding was repressed by UV, and salicylic acid had little effect. Since the binding of no single element correlated with the expression pattern of LDH, it is likely that multiple elements govern UV/salicylate-mediated expression

Hydroxysafflor yellow A suppress oleic acid-induced acute lung injury via protein kinase A

International Nuclear Information System (INIS)

Wang, Chaoyun; Huang, Qingxian; Wang, Chunhua; Zhu, Xiaoxi; Duan, Yunfeng; Yuan, Shuai; Bai, Xianyong

2013-01-01

Inflammation response and oxidative stress play important roles in acute lung injury (ALI). Activation of the cAMP/protein kinase A (PKA) signaling pathway may attenuate ALI by suppressing immune responses and inhibiting the generation of reactive oxygen species (ROS). Hydroxysafflor yellow A (HSYA) is a natural flavonoid compound that reduces oxidative stress and inflammatory cytokine-mediated damage. In this study, we examined whether HSYA could protect the lungs from oleic acid (OA)-induced injury, which was used to mimic ALI, and determined the role of the cAMP/PKA signaling pathway in this process. Arterial oxygen tension (PaO 2 ), carbon dioxide tension, pH, and the PaO 2 /fraction of inspired oxygen ratio in the blood were detected using a blood gas analyzer. We measured wet/dry lung weight ratio and evaluated tissue morphology. The protein and inflammatory cytokine levels in the bronchoalveolar lavage fluid and serum were determined using enzyme-linked immunoassay. The activities of superoxide dismutase, glutathione peroxidase, PKA, and nicotinamide adenine dinucleotide phosphate oxidase, and the concentrations of cAMP and malondialdehyde in the lung tissue were detected using assay kits. Bcl-2, Bax, caspase 3, and p22 phox levels in the lung tissue were analyzed using Western blotting. OA increased the inflammatory cytokine and ROS levels and caused lung dysfunction by decreasing cAMP synthesis, inhibiting PKA activity, stimulating caspase 3, and reducing the Bcl-2/Bax ratio. H-89 increased these effects. HSYA significantly increased the activities of antioxidant enzymes, inhibited the inflammatory response via cAMP/PKA pathway activation, and attenuated OA-induced lung injury. Our results show that the cAMP/PKA signaling pathway is required for the protective effect of HSYA against ALI. - Highlights: • Oleic acid (OA) cause acute lung injury (ALI) via inhibiting cAMP/PKA signal pathway. • Blocking protein kinase A (PKA) activation may enhance Cytokine

A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid

Energy Technology Data Exchange (ETDEWEB)

Arceo, Elena; Ellman, Jonathan; Bergman, Robert

2010-05-03

An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.

Myristoylation of Src kinase mediates Src-induced and high-fat diet-accelerated prostate tumor progression in mice.

Science.gov (United States)

Kim, Sungjin; Yang, Xiangkun; Li, Qianjin; Wu, Meng; Costyn, Leah; Beharry, Zanna; Bartlett, Michael G; Cai, Houjian

2017-11-10

Exogenous fatty acids provide substrates for energy production and biogenesis of the cytoplasmic membrane, but they also enhance cellular signaling during cancer cell proliferation. However, it remains controversial whether dietary fatty acids are correlated with tumor progression. In this study, we demonstrate that increased Src kinase activity is associated with high-fat diet-accelerated progression of prostate tumors and that Src kinases mediate this pathological process. Moreover, in the in vivo prostate regeneration assay, host SCID mice carrying Src(Y529F)-transduced regeneration tissues were fed a low-fat diet or a high-fat diet and treated with vehicle or dasatinib. The high-fat diet not only accelerated Src-induced prostate tumorigenesis in mice but also compromised the inhibitory effect of the anticancer drug dasatinib on Src kinase oncogenic potential in vivo We further show that myristoylation of Src kinase is essential to facilitate Src-induced and high-fat diet-accelerated tumor progression. Mechanistically, metabolism of exogenous myristic acid increased the biosynthesis of myristoyl CoA and myristoylated Src and promoted Src kinase-mediated oncogenic signaling in human cells. Of the fatty acids tested, only exogenous myristic acid contributed to increased intracellular myristoyl CoA levels. Our results suggest that targeting Src kinase myristoylation, which is required for Src kinase association at the cellular membrane, blocks dietary fat-accelerated tumorigenesis in vivo Our findings uncover the molecular basis of how the metabolism of myristic acid stimulates high-fat diet-mediated prostate tumor progression. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Cell-mediated immune responses in the head-associated lymphoid tissues induced to a live attenuated avian coronavirus vaccine.

Science.gov (United States)

Gurjar, Rucha S; Gulley, Stephen L; van Ginkel, Frederik W

2013-12-01

Humoral immunity is important for controlling viral diseases of poultry, but recent studies have indicated that cytotoxic T cells also play an important role in the immune response to infectious bronchitis virus (IBV). To better understand the cell mediated immune responses to IBV in the mucosal and systemic immune compartments chickens were ocularly vaccinated with IBV. This induced a lymphocyte expansion in head-associated lymphoid tissues (HALT) and to a lesser extent in the spleen, followed by a rapid decline, probably due to homing of lymphocytes out of these organs and contraction of the lymphocyte population. This interpretation was supported by observations that changes in mononuclear cells were mirrored by that in CD3(+)CD44(+) T cell abundance, which presumably represent T effector cells. Increased interferon gamma (IFN-γ) expression was observed in the mucosal immune compartment, i.e., HALT, after primary vaccination, but shifted to the systemic immune compartment after boosting. In contrast, the expression of cytotoxicity-associated genes, i.e., granzyme A (GZMA) and perforin mRNA, remained associated with the HALT after boosting. Thus, an Ark-type IBV ocular vaccine induces a central memory IFN-γ response in the spleen while the cytotoxic effector memory response, as measured by GZMA and perforin mRNA expression, remains associated with CALT after boosting. Copyright © 2013. Published by Elsevier Ltd.

Perception of low red:far-red ratio compromises both salicylic acid- and jasmonic acid-dependent pathogen defences in Arabidopsis.

Science.gov (United States)

de Wit, Mieke; Spoel, Steven H; Sanchez-Perez, Gabino F; Gommers, Charlotte M M; Pieterse, Corné M J; Voesenek, Laurentius A C J; Pierik, Ronald

2013-07-01

In dense stands of plants, such as agricultural monocultures, plants are exposed simultaneously to competition for light and other stresses such as pathogen infection. Here, we show that both salicylic acid (SA)-dependent and jasmonic acid (JA)-dependent disease resistance is inhibited by a simultaneously reduced red:far-red light ratio (R:FR), the early warning signal for plant competition. Conversely, SA- and JA-dependent induced defences did not affect shade-avoidance responses to low R:FR. Reduced pathogen resistance by low R:FR was accompanied by a strong reduction in the regulation of JA- and SA-responsive genes. The severe inhibition of SA-responsive transcription in low R:FR appeared to be brought about by the repression of SA-inducible kinases. Phosphorylation of the SA-responsive transcription co-activator NPR1, which is required for full induction of SA-responsive transcription, was indeed reduced and may thus play a role in the suppression of SA-mediated defences by low R:FR-mediated phytochrome inactivation. Our results indicate that foraging for light through the shade-avoidance response is prioritised over plant immune responses when plants are simultaneously challenged with competition and pathogen attack. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

Radiation-induced genomic instability and bystander effects: related inflammatory-type responses to radiation-induced stress and injury? A review.

Science.gov (United States)

Lorimore, S A; Wright, E G

2003-01-01

To review studies of radiation responses in the haemopoietic system in the context of radiation-induced genomic instability, bystander effects and inflammatory-type processes. There is considerable evidence that cells that themselves are not exposed to ionizing radiation but are the progeny of cells irradiated many cell divisions previously may express a high frequency of gene mutations, chromosomal aberrations and cell death. These effects are collectively known as radiation-induced genomic instability. A second untargeted effect results in non-irradiated cells exhibiting responses typically associated with direct radiation exposure but occurs as a consequence of contact with irradiated cells or by receiving soluble signals from irradiated cells. These effects are collectively known as radiation-induced bystander effects. Reported effects include increases or decreases in damage-inducible and stress-related proteins; increases or decreases in reactive oxygen species, cell death or cell proliferation, and induction of mutations and chromosome aberrations. This array of responses is reminiscent of effects mediated by cytokines and other similar regulatory factors that may involve, but do not necessarily require, gap junction-mediated transfer, have multiple inducers and a variety of context-dependent consequences in different cell systems. That chromosomal instability in haemopoietic cells can be induced by an indirect bystander-type mechanism both in vitro and in vivo provides a potential link between these two untargeted effects and there are radiation responses in vivo consistent with the microenvironment contributing secondary cell damage as a consequence of an inflammatory-type response to radiation-induced injury. Intercellular signalling, production of cytokines and free radicals are features of inflammatory responses that have the potential for both bystander-mediated and persisting damage as well as for conferring a predisposition to malignancy. The

β-aminobutyric acid mediated drought stress alleviation in maize (Zea mays L.).

Science.gov (United States)

Shaw, Arun K; Bhardwaj, Pardeep K; Ghosh, Supriya; Roy, Sankhajit; Saha, Suman; Sherpa, Ang R; Saha, Samir K; Hossain, Zahed

2016-02-01

The present study highlights the role of β-aminobutyric acid (BABA) in alleviating drought stress effects in maize (Zea mays L.). Chemical priming was imposed by pretreating 1-week-old plants with 600 μM BABA prior to applying drought stress. Specific activities of key antioxidant enzymes and metabolites (ascorbate and glutathione) levels of ascorbate-glutathione cycle were studied to unravel the priming-induced modulation of plant defense system. Furthermore, changes in endogenous ABA and JA concentrations as well as mRNA expressions of key genes involved in their respective biosynthesis pathways were monitored in BABA-primed (BABA+) and non-primed (BABA-) leaves of drought-challenged plants to better understand the mechanistic insights into the BABA-induced hormonal regulation of plant response to water-deficit stress. Accelerated stomatal closure, high relative water content, and less membrane damage were observed in BABA-primed leaves under water-deficit condition. Elevated APX and SOD activity in non-primed leaves found to be insufficient to scavenge all H2O2 and O2 (·-) resulting in oxidative burst as evident after histochemical staining with NBT and DAB. A higher proline accumulation in non-primed leaves also does not give much protection against drought stress. Increased GR activity supported with the enhanced mRNA and protein expressions might help the BABA-primed plants to maintain a high GSH pool essential for sustaining balanced redox status to counter drought-induced oxidative stress damages. Hormonal analysis suggests that in maize, BABA-potentiated drought tolerance is primarily mediated through JA-dependent pathway by the activation of antioxidant defense systems while ABA biosynthesis pathway also plays an important role in fine-tuning of drought stress response.

Identification of amino acid residues in the ligand-binding domain of the aryl hydrocarbon receptor causing the species-specific response to omeprazole: possible determinants for binding putative endogenous ligands.

Science.gov (United States)

Shiizaki, Kazuhiro; Ohsako, Seiichiroh; Kawanishi, Masanobu; Yagi, Takashi

2014-02-01

Omeprazole (OME) induces the expression of genes encoding drug-metabolizing enzymes, such as CYP1A1, via activation of the aryl hydrocarbon receptor (AhR) both in vivo and in vitro. However, the precise mechanism of OME-mediated AhR activation is still under investigation. While elucidating species-specific susceptibility to dioxin, we found that OME-mediated AhR activation was mammalian species specific. Moreover, we previously reported that OME has inhibitory activity toward CYP1A1 enzymes. From these observations, we speculated that OME-mediated AhR target gene transcription is due to AhR activation by increasing amounts of putative AhR ligands in serum by inhibition of CYP1A1 activity. We compared the amino acid sequences of OME-sensitive rabbit AhR and nonsensitive mouse AhR to identify the residues responsible for the species-specific response. Chimeric AhRs were constructed by exchanging domains between mouse and rabbit AhRs to define the region required for the response to OME. OME-mediated transactivation was observed only with the chimeric AhR that included the ligand-binding domain (LBD) of the rabbit AhR. Site-directed mutagenesis revealed three amino acids (M328, T353, and F367) in the rabbit AhR that were responsible for OME-mediated transactivation. Replacing these residues with those of the mouse AhR abolished the response of the rabbit AhR. In contrast, substitutions of these amino acids with those of the rabbit AhR altered nonsensitive mouse AhR to become sensitive to OME. These results suggest that OME-mediated AhR activation requires a specific structure within LBD that is probably essential for binding with enigmatic endogenous ligands.

Cyclosporine A and palmitic acid treatment synergistically induce cytotoxicity in HepG2 cells

Energy Technology Data Exchange (ETDEWEB)

Luo, Yi, E-mail: yi.luo@pfizer.com; Rana, Payal; Will, Yvonne

2012-06-01

Immunosuppressant cyclosporine A (CsA) treatment can cause severe side effects. Patients taking immunosuppressant after organ transplantation often display hyperlipidemia and obesity. Elevated levels of free fatty acids have been linked to the etiology of metabolic syndromes, nonalcoholic fatty liver and steatohepatitis. The contribution of free fatty acids to CsA-induced toxicity is not known. In this study we explored the effect of palmitic acid on CsA-induced toxicity in HepG2 cells. CsA by itself at therapeutic exposure levels did not induce detectible cytotoxicity in HepG2 cells. Co-treatment of palmitic acid and CsA resulted in a dose dependent increase in cytotoxicity, suggesting that fatty acid could sensitize cells to CsA-induced cytotoxicity at the therapeutic doses of CsA. A synergized induction of caspase-3/7 activity was also observed, indicating that apoptosis may contribute to the cytotoxicity. We demonstrated that CsA reduced cellular oxygen consumption which was further exacerbated by palmitic acid, implicating that impaired mitochondrial respiration might be an underlying mechanism for the enhanced toxicity. Inhibition of c-Jun N-terminal kinase (JNK) attenuated palmitic acid and CsA induced toxicity, suggesting that JNK activation plays an important role in mediating the enhanced palmitic acid/CsA-induced toxicity. Our data suggest that elevated FFA levels, especially saturated FFA such as palmitic acid, may be predisposing factors for CsA toxicity, and patients with underlying diseases that would elevate free fatty acids may be susceptible to CsA-induced toxicity. Furthermore, hyperlipidemia/obesity resulting from immunosuppressive therapy may aggravate CsA-induced toxicity and worsen the outcome in transplant patients. -- Highlights: ► Palmitic acid and cyclosporine (CsA) synergistically increased cytotoxicity. ► The impairment of mitochondrial functions may contribute to the enhanced toxicity. ► Inhibition of JNK activity attenuated

Salvianolic acid A preconditioning confers protection against concanavalin A-induced liver injury through SIRT1-mediated repression of p66shc in mice

Energy Technology Data Exchange (ETDEWEB)

Xu, Xiaomei; Hu, Yan; Zhai, Xiaohan; Lin, Musen [Department of Pharmacology, Dalian Medical University, Dalian 116044 (China); Chen, Zhao; Tian, Xiaofeng; Zhang, Feng [Department of General Surgery, Second Affiliated Hospital of Dalian Medical University, Dalian 116023 (China); Gao, Dongyan; Ma, Xiaochi [Department of Pharmacology, Dalian Medical University, Dalian 116044 (China); Lv, Li, E-mail: lv_li@126.com [Department of Pharmacology, Dalian Medical University, Dalian 116044 (China); Yao, Jihong, E-mail: Yaojihong65@hotmail.com [Department of Pharmacology, Dalian Medical University, Dalian 116044 (China)

2013-11-15

Salvianolic acid A (SalA) is a phenolic carboxylic acid derivative extracted from Salvia miltiorrhiza. It has many biological and pharmaceutical activities. The purpose of this study was to investigate the effect of SalA on concanavalin A (ConA)-induced acute hepatic injury in Kunming mice and to explore the role of SIRT1 in such an effect. The results showed that in vivo pretreatment with SalA significantly reduced ConA-induced elevation in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities and decreased levels of the hepatotoxic cytokines such as interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α). Moreover, the SalA pretreatment ameliorated the increases in NF-κB and in cleaved caspase-3 caused by ConA exposure. Whereas, the pretreatment completely reversed expression of the B-cell lymphoma-extra large (Bcl-xL). More importantly, the SalA pretreatment significantly increased the expression of SIRT1, a NAD{sup +}-dependent deacetylase, which was known to attenuate acute hypoxia damage and metabolic liver diseases. In our study, the increase in SIRT1 was closely associated with down-regulation of the p66 isoform (p66shc) of growth factor adapter Shc at both protein and mRNA levels. In HepG2 cell culture, SalA pretreatment increased SIRT1 expression in a time and dose-dependent manner and such an increase was abrogated by siRNA knockdown of SIRT1. Additionally, inhibition of SIRT1 significantly reversed the decreased expression of p66shc, and attenuated SalA-induced p66shc down-regulation. Collectively, the present study indicated that SalA may be a potent activator of SIRT and that SalA can alleviate ConA-induced hepatitis through SIRT1-mediated repression of the p66shc pathway. - Highlights: • We report for the first time that SalA protects against ConA-induced hepatitis. • We find that SalA is a potential activator of SIRT1. • SalA's protection against hepatitis involves SIRT1-mediated repression of p

Salicylic acid inhibits UV- and Cis-Pt-induced human immunodeficiency virus expression

International Nuclear Information System (INIS)

Woloschak, G.E.; Panozzo, J.; Libertin, C.R.; Schreck, S.; South Carolina Univ., Columbia, SC

1994-01-01

Previous studies have shown that exposure of HeLa cells stably transfected with a human immunodeficiency virus-long terminal repeat-chloramphenicol acetyl transferase (HIV-LTR-CAT) construct to UV light-induced expression from the HIV LTR. By culturing the cells with salicylic acid we demonstrated dose-dependent repression of this induced HIV expression. Repression was evident if salicylic acid was administered 2 h before, at the same time as, or up to 6 h after exposure to the DNA-damaging agent. The kinetics were similar for UV- and for cis-Pt-induced HIV expression, and induction was dependent on the UV dose or cis-Pt concentration added to the culture. These results suggest a role for the prostaglandins or the cyclooxygenase pathway or both in HIV induction mediated by DNA-damaging agents

Generation of TCR-Expressing Innate Lymphoid-like Helper Cells that Induce Cytotoxic T Cell-Mediated Anti-leukemic Cell Response.

Science.gov (United States)

Ueda, Norihiro; Uemura, Yasushi; Zhang, Rong; Kitayama, Shuichi; Iriguchi, Shoichi; Kawai, Yohei; Yasui, Yutaka; Tatsumi, Minako; Ueda, Tatsuki; Liu, Tian-Yi; Mizoro, Yasutaka; Okada, Chihiro; Watanabe, Akira; Nakanishi, Mahito; Senju, Satoru; Nishimura, Yasuharu; Kuzushima, Kiyotaka; Kiyoi, Hitoshi; Naoe, Tomoki; Kaneko, Shin

2018-06-05

CD4 + T helper (Th) cell activation is essential for inducing cytotoxic T lymphocyte (CTL) responses against malignancy. We reprogrammed a Th clone specific for chronic myelogenous leukemia (CML)-derived b3a2 peptide to pluripotency and re-differentiated the cells into original TCR-expressing T-lineage cells (iPS-T cells) with gene expression patterns resembling those of group 1 innate lymphoid cells. CD4 gene transduction into iPS-T cells enhanced b3a2 peptide-specific responses via b3a2 peptide-specific TCR. iPS-T cells upregulated CD40 ligand (CD40L) expression in response to interleukin-2 and interleukin-15. In the presence of Wilms tumor 1 (WT1) peptide, antigen-specific dendritic cells (DCs) conditioned by CD4-modified CD40L high iPS-T cells stimulated WT1-specific CTL priming, which eliminated WT1 peptide-expressing CML cells in vitro and in vivo. Thus, CD4 modification of CD40L high iPS-T cells generates innate lymphoid helper-like cells inducing bcr-abl-specific TCR signaling that mediates effectiveanti-leukemic CTL responses via DC maturation, showing potential for adjuvant immunotherapy against leukemia. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

How salicylic acid takes transcriptional control over jasmonic acid signaling

Directory of Open Access Journals (Sweden)

Lotte eCaarls

2015-03-01

Full Text Available Transcriptional regulation is a central process in plant immunity. The induction or repression of defense genes is orchestrated by signaling networks that are directed by plant hormones of which salicylic acid (SA and jasmonic acid (JA are the major players. Extensive cross-communication between the hormone signaling pathways allows for fine tuning of transcriptional programs, determining resistance to invaders and trade-offs with plant development. Here, we give an overview of how SA can control transcriptional reprogramming of JA-induced genes in Arabidopsis thaliana. SA can influence activity and/or localization of transcriptional regulators by post-translational modifications of transcription factors and co-regulators. SA-induced redox changes, mediated by thioredoxins and glutaredoxins, modify transcriptional regulators that are involved in suppression of JA-dependent genes, such as NPR1 and TGA transcription factors, which affects their localization or DNA binding activity. Furthermore, SA can mediate sequestering of JA-responsive transcription factors away from their target genes by stalling them in the cytosol or in complexes with repressor proteins in the nucleus. SA also affects JA-induced transcription by inducing degradation of transcription factors with an activating role in JA signaling, as was shown for the ERF transcription factor ORA59. Additionally, SA can induce negative regulators, among which WRKY transcription factors, that can directly or indirectly inhibit JA-responsive gene expression. Finally, at the DNA level, modification of histones by SA-dependent factors can result in repression of JA-responsive genes. These diverse and complex regulatory mechanisms affect important signaling hubs in the integration of hormone signaling networks. Some pathogens have evolved effectors that highjack hormone crosstalk mechanisms for their own good, which are described in this review as well.

Gender difference following high cholesterol diet induced renal injury and the protective role of rutin and ascorbic acid combination in Wistar albino rats

OpenAIRE

Al-Rejaie, Salim Salih; Abuohashish, Hatem Mustafa; Alkhamees, Osama Abdelrahman; Aleisa, Abdulaziz Mohammed; Alroujayee, Abdulaziz S

2012-01-01

Abstract Background An increased interest is given to the impact of high fat diet on health worldwide. Abnormalities in lipid metabolism induced by high cholesterol diet (HCD) were reported to exacerbate renal diseases via oxidative stress pathways. Rutin and ascorbic acid showed a protective role against oxidative stress-mediated diseases. Furthermore, both lipid metabolism and tissue response to oxidative stress damage was found to vary according to animal gender. Thus, the objective of thi...

Responsiveness to acidity via metal ion regulators mediates virulence in the gastric pathogen Helicobacter pylori.

Science.gov (United States)

Bury-Moné, Stéphanie; Thiberge, Jean-Michel; Contreras, Monica; Maitournam, Aboubakar; Labigne, Agnès; De Reuse, Hilde

2004-07-01

The virulence of pathogenic bacteria is dependent on their adaptation to and survival in the stressful conditions encountered in their hosts. Helicobacter pylori exclusively colonizes the acid stomach of primates, making it an ideal study model. Little is known about how H. pylori responds to the moderately acidic conditions encountered at its colonization site, the gastric mucus layer. Thus, we compared gene expression profiles of H. pylori 26695 grown at neutral and acidic pH, and validated the data for a selection of genes by real-time polymerase chain reaction, dot-blots or enzymatic assays. During growth in acidic conditions, 56 genes were upregulated and 45 genes downregulated. We found that acidity is a signal modulating the expression of several virulence factors. Regulation of genes related to metal ion homeostasis suggests protective mechanisms involving diminished transport and enhanced storage. Genes encoding subunits of the F0F1 ATPase and of a newly identified Na+/H+ antiporter (NhaC-HP0946) were downregulated, revealing that this bacterium uses original mechanisms to control proton entry. Five of the upregulated genes encoded proteins controlling intracellular ammonia synthesis, including urease, amidase and formamidase, underlining the major role of this buffering compound in the protection against acidity in H. pylori. Regulatory networks and transcriptome analysis as well as enzymatic assays implicated two metal-responsive transcriptional regulators (NikR and Fur) and an essential two-component response regulator (HP0166, OmpR-like) as effectors of the H. pylori acid response. Finally, a nikR-fur mutant is attenuated in the mouse model, emphasizing the link between response to acidity, metal metabolism and virulence in this gastric pathogen.

Profiling Abscisic Acid-Induced Changes in Fatty Acid Composition in Mosses.

Science.gov (United States)

Shinde, Suhas; Devaiah, Shivakumar; Kilaru, Aruna

2017-01-01

In plants, change in lipid composition is a common response to various abiotic stresses. Lipid constituents of bryophytes are of particular interest as they differ from that of flowering plants. Unlike higher plants, mosses have high content of very long-chain polyunsaturated fatty acids. Such lipids are considered to be important for survival of nonvascular plants. Here, using abscisic acid (ABA )-induced changes in lipid composition in Physcomitrella patens as an example, a protocol for total lipid extraction and quantification by gas chromatography (GC) coupled with flame ionization detector (FID) is described.

Apoplastic peroxidases are required for salicylic acid-mediated defense against Pseudomonas syringae.

Science.gov (United States)

Mammarella, Nicole D; Cheng, Zhenyu; Fu, Zheng Qing; Daudi, Arsalan; Bolwell, G Paul; Dong, Xinnian; Ausubel, Frederick M

2015-04-01

Reactive oxygen species (ROS) generated by NADPH oxidases or apoplastic peroxidases play an important role in the plant defense response. Diminished expression of at least two Arabidopsis thaliana peroxidase encoding genes, PRX33 (At3g49110) and PRX34 (At3g49120), as a consequence of anti-sense expression of a heterologous French bean peroxidase gene (asFBP1.1), were previously shown to result in reduced levels of ROS following pathogen attack, enhanced susceptibility to a variety of bacterial and fungal pathogens, and reduced levels of callose production and defense-related gene expression in response to the microbe associated molecular pattern (MAMP) molecules flg22 and elf26. These data demonstrated that the peroxidase-dependent oxidative burst plays an important role in the elicitation of pattern-triggered immunity (PTI). Further work reported in this paper, however, shows that asFBP1.1 antisense plants are not impaired in all PTI-associated responses. For example, some but not all flg22-elicited genes are induced to lower levels by flg22 in asFPB1.1, and callose deposition in asFPB1.1 is similar to wild-type following infiltration with a Pseudomonas syringae hrcC mutant or with non-host P. syringae pathovars. Moreover, asFPB1.1 plants did not exhibit any apparent defect in their ability to mount a hypersensitive response (HR). On the other hand, salicylic acid (SA)-mediated activation of PR1 was dramatically impaired in asFPB1.1 plants. In addition, P. syringae-elicited expression of many genes known to be SA-dependent was significantly reduced in asFBP1.1 plants. Consistent with this latter result, in asFBP1.1 plants the key regulator of SA-mediated responses, NPR1, showed both dramatically decreased total protein abundance and a failure to monomerize, which is required for its translocation into the nucleus. Copyright © 2014 Elsevier Ltd. All rights reserved.

TMEM16A mediates the hypersecretion of mucus induced by Interleukin-13

Energy Technology Data Exchange (ETDEWEB)

Lin, Jiachen; Jiang, Youfan; Li, Li; Liu, Yanan; Tang, Hui; Jiang, Depeng, E-mail: depengjiang@163.com

2015-06-10

Previous studies showed that the Ca{sup 2+}-activated Cl{sup −} channel (CaCC) was involved in the pathogenesis of mucus hypersecretion induced by Interleukin-13 (IL-13). However, the mechanisms underlying the process were unknown. Recently, transmembrane protein 16A (TMEM16A) was identified as the channel underlying the CaCC current. The aim of the current study was to investigate whether the TMEM16A channel is part of the mechanism underlying IL-13-induced mucus hypersecretion. We observed that both TMEM16A mRNA and protein expression were significantly up-regulated after treatment with IL-13 in human bronchial epithelial 16 (HBE 16) cells, which correlated with an increase in mucus production. Additionally, mucus hypersecretion in rat airways was induced by intratracheal instillation of IL-13 and similar increases were observed in the expression of TMEM16A mRNA and protein in the bronchial epithelium. Niflumic acid (NA), a selective antagonist of CaCC, markedly blocked IL-13-induced mucin (MUC) 5AC mRNA and protein production in vivo and in vitro. Further investigation with HBE16 cells revealed that TMEM16A overexpression clearly promoted mucus production, IκBα phosphorylation, and p65 accumulation in the nucleus. The loss of TMEM16A resulted in inhibition of mucus production, and the TMEM16A-mediated production of MUC5AC was significantly blocked by a nuclear factor-kappa B (NF-κB) inhibitor. Therefore, the TMEM16A channel acts upstream of NF-κB in the regulation of mucus production. This is the first demonstration that the TMEM16A-NF-κB pathway is positively involved in IL-13-induced mucus production, which provides novel insight into the molecular mechanism of mucin overproduction. - Highlights: • TMEM16A acts as downstream events of IL-13 signaling pathway. • Established the link between TMEM16A and mucus hypersecretion. • NF-κB activation might be responsible for TMEM16A mediated mucus secretion.

Castor oil induces laxation and uterus contraction via ricinoleic acid activating prostaglandin EP3 receptors

OpenAIRE

Tunaru, Sorin; Althoff, Till F.; Nüsing, Rolf M.; Diener, Martin; Offermanns, Stefan

2012-01-01

Castor oil is one of the oldest drugs. When given orally, it has a laxative effect and induces labor in pregnant females. The effects of castor oil are mediated by ricinoleic acid, a hydroxylated fatty acid released from castor oil by intestinal lipases. Despite the wide-spread use of castor oil in conventional and folk medicine, the molecular mechanism by which ricinoleic acid acts remains unknown. Here we show that the EP3 prostanoid receptor is specifically activated by ricinoleic acid and...

Effect of oral amino acids on counterregulatory responses and cognitive function during insulin-induced hypoglycemia in nondiabetic and type 1 diabetic people.

Science.gov (United States)

Rossetti, Paolo; Porcellati, Francesca; Busciantella Ricci, Natalia; Candeloro, Paola; Cioli, Patrizia; Nair, K Sreekumaran; Santeusanio, Fausto; Bolli, Geremia B; Fanelli, Carmine G

2008-07-01

Amino acids stimulate glucagon responses to hypoglycemia and may be utilized by the brain. The aim of this study was to assess the responses to hypoglycemia in nondiabetic and type 1 diabetic subjects after ingestion of an amino acid mixture. Ten nondiabetic and 10 diabetic type 1 subjects were studied on three different occasions during intravenous insulin (2 mU . kg(-1) . min(-1)) plus variable glucose for 160 min. In two studies, clamped hypoglycemia (47 mg/dl plasma glucose for 40 min) was induced and either oral placebo or an amino acid mixture (42 g) was given at 30 min. In the third study, amino acids were given, but euglycemia was maintained. Plasma glucose and insulin were no different in the hypoglycemia studies with both placebo and amino acids (P > 0.2). After the amino acid mixture, plasma amino acid concentrations increased to levels observed after a mixed meal (2.4 +/- 0.13 vs. placebo study 1.7 +/- 0.1 mmol/l, P = 0.02). During clamped euglycemia, ingestion of amino acids resulted in transient increases in glucagon concentrations, which returned to basal by the end of the study. During clamped hypoglycemia, glucagon response was sustained and increased more in amino acid studies versus placebo in nondiabetic and diabetic subjects (P colored words, and verbal memory tests for nondiabetic subjects; and Trail-Making part B, digit span backward, and Stroop color tests for diabetic subjects. Oral amino acids improve cognitive function in response to hypoglycemia and enhance the response of glucagon in nondiabetic and diabetic subjects.

The pearl millet mitogen-activated protein kinase PgMPK4 is involved in responses to downy mildew infection and in jasmonic- and salicylic acid-mediated defense.

Science.gov (United States)

Melvin, Prasad; Prabhu, S Ashok; Veena, Mariswamy; Shailasree, Sekhar; Petersen, Morten; Mundy, John; Shetty, Shekar H; Kini, K Ramachandra

2015-02-01

Plant mitogen-activated protein kinases (MPKs) transduce signals required for the induction of immunity triggered by host recognition of pathogen-associated molecular patterns. We isolated a full-length cDNA of a group B MPK (PgMPK4) from pearl millet. Autophosphorylation assay of recombinant PgMPK4 produced in Escherichia coli confirmed it as a kinase. Differential accumulation of PgMPK4 mRNA and kinase activity was observed between pearl millet cultivars 852B and IP18292 in response to inoculation with the downy mildew oomycete pathogen Sclerospora graminicola. This increased accumulation of PgMPK4 mRNA, kinase activity as well as nuclear-localization of PgMPK protein(s) was only detected in the S. graminicola resistant cultivar IP18292 with a ~tenfold peak at 9 h post inoculation. In the susceptible cultivar 852B, PgMPK4 mRNA and immuno-detectable nuclear PgMPK could be induced by application of the chemical elicitor β-amino butyric acid, the non-pathogenic bacteria Pseudomonas fluorescens, or by the phytohormones jasmonic acid (JA) or salicylic acid (SA). Furthermore, kinase inhibitor treatments indicated that PgMPK4 is involved in the JA- and SA-mediated expression of three defense genes, lipoxygenase, catalase 3 and polygalacturonase-inhibitor protein. These findings indicate that PgMPK/s contribute to pearl millet defense against the downy mildew pathogen by activating the expression of defense proteins.

Suppression of gastric acid increases the risk of developing immunoglobulin E-mediated drug hypersensitivity: human diclofenac sensitization and a murine sensitization model.

Science.gov (United States)

Riemer, A B; Gruber, S; Pali-Schöll, I; Kinaciyan, T; Untersmayr, E; Jensen-Jarolim, E

2010-03-01

Hypersensitivity reactions towards non-steroidal anti-inflammatory drugs (NSAID) are common, although true allergies are detectable only in a subgroup of patients. The current study was prompted by a case observation, where a patient experienced generalized urticaria following his second course of diclofenac and proton pump inhibitor medication, and was found to have diclofenac-specific IgE. During recent years, our group has been investigating the importance of gastric digestion in the development of food allergies, demonstrating anti-acid medication as a risk factor for sensitization against food proteins. Here, we aimed to investigate whether the mechanism of food allergy induction described can also be causative in NSAID allergy, using diclofenac as a paradigm. We subjected BALB/c mice to several oral immunization regimens modelled after the patient's medication intake. Diclofenac was applied with or without gastric acid suppression, in various doses, alone or covalently coupled to albumin, a protein abundant in gastric juices. Immune responses were assessed on the antibody level, and functionally examined by in vitro and in vivo crosslinking assays. Only mice receiving albumin-coupled diclofenac under gastric acid suppression developed anti-diclofenac IgG1 and IgE, whereas no immune responses were induced by the drug alone or without gastric acid suppression. Antibody induction was dose dependent with the group receiving the higher dose of the drug showing sustained anti-diclofenac titres. The antibodies induced triggered basophil degranulation in vitro and positive skin tests in vivo. Gastric acid suppression was found to be a causative mechanism in the induction of IgE-mediated diclofenac allergy.

Chitosan oligosaccharide induces resistance to Tobacco mosaic virus in Arabidopsis via the salicylic acid-mediated signalling pathway.

Science.gov (United States)

Jia, Xiaochen; Meng, Qingshan; Zeng, Haihong; Wang, Wenxia; Yin, Heng

2016-05-18

Chitosan is one of the most abundant carbohydrate biopolymers in the world, and chitosan oligosaccharide (COS), which is prepared from chitosan, is a plant immunity regulator. The present study aimed to validate the effect of COS on inducing resistance to tobacco mosaic virus (TMV) in Arabidopsis and to investigate the potential defence-related signalling pathways involved. Optimal conditions for the induction of TMV resistance in Arabidopsis were COS pretreatment at 50 mg/L for 1 day prior to inoculation with TMV. Multilevel indices, including phenotype data, and TMV coat protein expression, revealed that COS induced TMV resistance in wild-type and jasmonic acid pathway- deficient (jar1) Arabidopsis plants, but not in salicylic acid pathway deficient (NahG) Arabidopsis plants. Quantitative-PCR and analysis of phytohormone levels confirmed that COS pretreatment enhanced the expression of the defence-related gene PR1, which is a marker of salicylic acid signalling pathway, and increased the amount of salicylic acid in WT and jar1, but not in NahG plants. Taken together, these results confirm that COS induces TMV resistance in Arabidopsis via activation of the salicylic acid signalling pathway.

Barrier protective effects of withaferin A in HMGB1-induced inflammatory responses in both cellular and animal models

International Nuclear Information System (INIS)

Lee, Wonhwa; Kim, Tae Hoon; Ku, Sae-Kwang; Min, Kyoung-jin; Lee, Hyun-Shik; Kwon, Taeg Kyu; Bae, Jong-Sup

2012-01-01

Withaferin A (WFA), an active compound from Withania somnifera, is widely researched for its anti-inflammatory, cardioactive and central nervous system effects. In this study, we first investigated the possible barrier protective effects of WFA against pro-inflammatory responses in human umbilical vein endothelial cells (HUVECs) and in mice induced by high mobility group box 1 protein (HMGB1) and the associated signaling pathways. The barrier protective activities of WFA were determined by measuring permeability, leukocytes adhesion and migration, and activation of pro-inflammatory proteins in HMGB1-activated HUVECs. We found that WFA inhibited lipopolysaccharide (LPS)-induced HMGB1 release and HMGB1-mediated barrier disruption, expression of cell adhesion molecules (CAMs) and adhesion/transendothelial migration of leukocytes to human endothelial cells. WFA also suppressed acetic acid-induced hyperpermeability and carboxymethylcellulose-induced leukocytes migration in vivo. Further studies revealed that WFA suppressed the production of interleukin 6, tumor necrosis factor-α (TNF-α) and activation of nuclear factor-κB (NF-κB) by HMGB1. Collectively, these results suggest that WFA protects vascular barrier integrity by inhibiting hyperpermeability, expression of CAMs, adhesion and migration of leukocytes, thereby endorsing its usefulness as a therapy for vascular inflammatory diseases. -- Highlights: ► Withaferin A inhibited LPS induced HMGB1 release. ► Withaferin A reduced HMGB1-mediated hyperpermeability. ► Withaferin A inhibited HMGB1-mediated adhesion and migration of leukocytes. ► Withaferin A inhibited HMGB1-mediated activation of NF-κB, IL-6 and TNF-α.

Barrier protective effects of withaferin A in HMGB1-induced inflammatory responses in both cellular and animal models

Energy Technology Data Exchange (ETDEWEB)

Lee, Wonhwa [College of Pharmacy, Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University (Korea, Republic of); Kim, Tae Hoon [Department of Herbal Medicinal Pharmacology, Daegu Haany University (Korea, Republic of); Ku, Sae-Kwang [Department of Anatomy and Histology, College of Oriental Medicine, Daegu Haany University, Gyeongsan 712-715 (Korea, Republic of); Min, Kyoung-jin [Department of Immunology, School of Medicine, Keimyung University, Daegu 704-701 (Korea, Republic of); Lee, Hyun-Shik [School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Kwon, Taeg Kyu [Department of Immunology, School of Medicine, Keimyung University, Daegu 704-701 (Korea, Republic of); Bae, Jong-Sup, E-mail: baejs@knu.ac.kr [College of Pharmacy, Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu 702-701 (Korea, Republic of)

2012-07-01

Withaferin A (WFA), an active compound from Withania somnifera, is widely researched for its anti-inflammatory, cardioactive and central nervous system effects. In this study, we first investigated the possible barrier protective effects of WFA against pro-inflammatory responses in human umbilical vein endothelial cells (HUVECs) and in mice induced by high mobility group box 1 protein (HMGB1) and the associated signaling pathways. The barrier protective activities of WFA were determined by measuring permeability, leukocytes adhesion and migration, and activation of pro-inflammatory proteins in HMGB1-activated HUVECs. We found that WFA inhibited lipopolysaccharide (LPS)-induced HMGB1 release and HMGB1-mediated barrier disruption, expression of cell adhesion molecules (CAMs) and adhesion/transendothelial migration of leukocytes to human endothelial cells. WFA also suppressed acetic acid-induced hyperpermeability and carboxymethylcellulose-induced leukocytes migration in vivo. Further studies revealed that WFA suppressed the production of interleukin 6, tumor necrosis factor-α (TNF-α) and activation of nuclear factor-κB (NF-κB) by HMGB1. Collectively, these results suggest that WFA protects vascular barrier integrity by inhibiting hyperpermeability, expression of CAMs, adhesion and migration of leukocytes, thereby endorsing its usefulness as a therapy for vascular inflammatory diseases. -- Highlights: ► Withaferin A inhibited LPS induced HMGB1 release. ► Withaferin A reduced HMGB1-mediated hyperpermeability. ► Withaferin A inhibited HMGB1-mediated adhesion and migration of leukocytes. ► Withaferin A inhibited HMGB1-mediated activation of NF-κB, IL-6 and TNF-α.

Bacteria-Triggered Systemic Immunity in Barley Is Associated with WRKY and ETHYLENE RESPONSIVE FACTORs But Not with Salicylic Acid1[C][W

Science.gov (United States)

Dey, Sanjukta; Wenig, Marion; Langen, Gregor; Sharma, Sapna; Kugler, Karl G.; Knappe, Claudia; Hause, Bettina; Bichlmeier, Marlies; Babaeizad, Valiollah; Imani, Jafargholi; Janzik, Ingar; Stempfl, Thomas; Hückelhoven, Ralph; Kogel, Karl-Heinz; Mayer, Klaus F.X.

2014-01-01

Leaf-to-leaf systemic immune signaling known as systemic acquired resistance is poorly understood in monocotyledonous plants. Here, we characterize systemic immunity in barley (Hordeum vulgare) triggered after primary leaf infection with either Pseudomonas syringae pathovar japonica (Psj) or Xanthomonas translucens pathovar cerealis (Xtc). Both pathogens induced resistance in systemic, uninfected leaves against a subsequent challenge infection with Xtc. In contrast to systemic acquired resistance in Arabidopsis (Arabidopsis thaliana), systemic immunity in barley was not associated with NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 or the local or systemic accumulation of salicylic acid. Instead, we documented a moderate local but not systemic induction of abscisic acid after infection of leaves with Psj. In contrast to salicylic acid or its functional analog benzothiadiazole, local applications of the jasmonic acid methyl ester or abscisic acid triggered systemic immunity to Xtc. RNA sequencing analysis of local and systemic transcript accumulation revealed unique gene expression changes in response to both Psj and Xtc and a clear separation of local from systemic responses. The systemic response appeared relatively modest, and quantitative reverse transcription-polymerase chain reaction associated systemic immunity with the local and systemic induction of two WRKY and two ETHYLENE RESPONSIVE FACTOR (ERF)-like transcription factors. Systemic immunity against Xtc was further associated with transcriptional changes after a secondary/systemic Xtc challenge infection; these changes were dependent on the primary treatment. Taken together, bacteria-induced systemic immunity in barley may be mediated in part by WRKY and ERF-like transcription factors, possibly facilitating transcriptional reprogramming to potentiate immunity. PMID:25332505

Receptor-mediated uptake of low density lipoprotein stimulates bile acid synthesis by cultured rat hepatocytes

International Nuclear Information System (INIS)

Junker, L.H.; Davis, R.A.

1989-01-01

The cellular mechanisms responsible for the lipoprotein-mediated stimulation of bile acid synthesis in cultured rat hepatocytes were investigated. Adding 280 micrograms/ml of cholesterol in the form of human or rat low density lipoprotein (LDL) to the culture medium increased bile acid synthesis by 1.8- and 1.6-fold, respectively. As a result of the uptake of LDL, the synthesis of [14C]cholesterol from [2-14C]acetate was decreased and cellular cholesteryl ester mass was increased. Further studies demonstrated that rat apoE-free LDL and apoE-rich high density lipoprotein (HDL) both stimulated bile acid synthesis 1.5-fold, as well as inhibited the formation of [14C]cholesterol from [2-14C]acetate. Reductive methylation of LDL blocked the inhibition of cholesterol synthesis, as well as the stimulation of bile acid synthesis, suggesting that these processes require receptor-mediated uptake. To identify the receptors responsible, competitive binding studies using 125I-labeled apoE-free LDL and 125I-labeled apoE-rich HDL were performed. Both apoE-free LDL and apoE-rich HDL displayed an equal ability to compete for binding of the other, suggesting that a receptor or a group of receptors that recognizes both apolipoproteins is involved. Additional studies show that hepatocytes from cholestyramine-treated rats displayed 2.2- and 3.4-fold increases in the binding of apoE-free LDL and apoE-rich HDL, respectively. These data show for the first time that receptor-mediated uptake of LDL by the liver is intimately linked to processes activating bile acid synthesis

Ultraviolet B irradiation induces changes in the distribution and release of arachidonic acid, dihomo-gamma-linolenic acid, and eicosapentaenoic acid in human keratinocytes in culture

International Nuclear Information System (INIS)

Punnonen, K.; Puustinen, T.; Jansen, C.T.

1987-01-01

There is increasing evidence that derivatives of 20-carbon polyunsaturated fatty acids, the eicosanoids, play an important role in the inflammatory responses of the human skin. To better understand the metabolic fate of fatty acids in the skin, the effect of ultraviolet B (UVB) irradiation (280-320 nm) on the distribution and release of 14 C-labeled arachidonic acid, dihomo-gamma-linolenic acid, and eicosapentaenoic acid in human keratinocytes in culture was investigated. Ultraviolet B irradiation induced the release of all three 14 C-labeled fatty acids from the phospholipids, especially from phosphatidylethanolamine, and this was accompanied by increased labeling of the nonphosphorus lipids. This finding suggests that UVB induces a significant liberation of eicosanoid precursor fatty acids from cellular phospholipids, but the liberated fatty acids are largely reincorporated into the nonphosphorus lipids. In conclusion, the present study suggests that not only arachidonic acid but also dihomo-gamma-linolenic acid, and eicosapentaenoic acid might be involved in the UVB irradiation-induced inflammatory reactions of human skin

Bile acid-induced necrosis in primary human hepatocytes and in patients with obstructive cholestasis

Energy Technology Data Exchange (ETDEWEB)

Woolbright, Benjamin L.; Dorko, Kenneth [Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, KS (United States); Antoine, Daniel J.; Clarke, Joanna I. [MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool (United Kingdom); Gholami, Parviz [Department of Internal Medicine, University of Kansas Medical Center, Kansas City, KS (United States); Li, Feng [Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, KS (United States); Kumer, Sean C.; Schmitt, Timothy M.; Forster, Jameson [Department of Surgery, University of Kansas Medical Center, Kansas City, KS (United States); Fan, Fang [Department of Pathology, University of Kansas Medical Center, Kansas City, KS (United States); Jenkins, Rosalind E.; Park, B. Kevin [MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool (United Kingdom); Hagenbuch, Bruno [Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, KS (United States); Olyaee, Mojtaba [Department of Internal Medicine, University of Kansas Medical Center, Kansas City, KS (United States); Jaeschke, Hartmut, E-mail: hjaeschke@kumc.edu [Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, KS (United States)

2015-03-15

Accumulation of bile acids is a major mediator of cholestatic liver injury. Recent studies indicate bile acid composition between humans and rodents is dramatically different, as humans have a higher percent of glycine conjugated bile acids and increased chenodeoxycholate content, which increases the hydrophobicity index of bile acids. This increase may lead to direct toxicity that kills hepatocytes, and promotes inflammation. To address this issue, this study assessed how pathophysiological concentrations of bile acids measured in cholestatic patients affected primary human hepatocytes. Individual bile acid levels were determined in serum and bile by UPLC/QTOFMS in patients with extrahepatic cholestasis with, or without, concurrent increases in serum transaminases. Bile acid levels increased in serum of patients with liver injury, while biliary levels decreased, implicating infarction of the biliary tracts. To assess bile acid-induced toxicity in man, primary human hepatocytes were treated with relevant concentrations, derived from patient data, of the model bile acid glycochenodeoxycholic acid (GCDC). Treatment with GCDC resulted in necrosis with no increase in apoptotic parameters. This was recapitulated by treatment with biliary bile acid concentrations, but not serum concentrations. Marked elevations in serum full-length cytokeratin-18, high mobility group box 1 protein (HMGB1), and acetylated HMGB1 confirmed inflammatory necrosis in injured patients; only modest elevations in caspase-cleaved cytokeratin-18 were observed. These data suggest human hepatocytes are more resistant to human-relevant bile acids than rodent hepatocytes, and die through necrosis when exposed to bile acids. These mechanisms of cholestasis in humans are fundamentally different to mechanisms observed in rodent models. - Highlights: • Cholestatic liver injury is due to cytoplasmic bile acid accumulation in hepatocytes. • Primary human hepatocytes are resistant to BA-induced injury

Memory responses of jasmonic acid-associated Arabidopsis genes to a repeated dehydration stress.

Science.gov (United States)

Liu, Ning; Staswick, Paul E; Avramova, Zoya

2016-11-01

Dehydration stress activates numerous genes co-regulated by diverse signaling pathways. Upon repeated exposures, however, a subset of these genes does not respond maintaining instead transcription at their initial pre-stressed levels ('revised-response' genes). Most of these genes are involved in jasmonic acid (JA) biosynthesis, JA-signaling and JA-mediated stress responses. How these JA-associated genes are regulated to provide different responses to similar dehydration stresses is an enigma. Here, we investigate molecular mechanisms that contribute to this transcriptional behavior. The memory-mechanism is stress-specific: one exposure to dehydration stress or to abscisic acid (ABA) is required to prevent transcription in the second. Both ABA-mediated and JA-mediated pathways are critical for the activation of these genes, but the two signaling pathways interact differently during a single or multiple encounters with dehydration stress. Synthesis of JA during the first (S1) but not the second dehydration stress (S2) accounts for the altered transcriptional responses. We propose a model for these memory responses, wherein lack of MYC2 and of JA synthesis in S2 is responsible for the lack of expression of downstream genes. The similar length of the memory displayed by different memory-type genes suggests biological relevance for transcriptional memory as a gene-regulating mechanism during recurring bouts of drought. © 2016 John Wiley & Sons Ltd.

TRIM32 promotes retinoic acid receptor α-mediated differentiation in human promyelogenous leukemic cell line HL60

International Nuclear Information System (INIS)

Sato, Tomonobu; Okumura, Fumihiko; Iguchi, Akihiro; Ariga, Tadashi; Hatakeyama, Shigetsugu

2012-01-01

Highlights: ► TRIM32 enhanced RARα-mediated transcriptional activity even in the absence of RA. ► TRIM32 stabilized RARα in the human promyelogenous leukemic cell line HL60. ► Overexpression of TRIM32 in HL60 cells induced granulocytic differentiation. ► TRIM32 may function as a coactivator for RARα-mediated transcription in APL cells. -- Abstract: Ubiquitination, one of the posttranslational modifications, appears to be involved in the transcriptional activity of nuclear receptors including retinoic acid receptor α (RARα). We previously reported that an E3 ubiquitin ligase, TRIM32, interacts with several important proteins including RARα and enhances transcriptional activity of RARα in mouse neuroblastoma cells and embryonal carcinoma cells. Retinoic acid (RA), which acts as a ligand to nuclear receptors including RARα, plays crucial roles in development, differentiation, cell cycles and apoptosis. In this study, we found that TRIM32 enhances RARα-mediated transcriptional activity even in the absence of RA and stabilizes RARα in the human promyelogenous leukemic cell line HL60. Moreover, we found that overexpression of TRIM32 in HL60 cells suppresses cellular proliferation and induces granulocytic differentiation even in the absence of RA. These findings suggest that TRIM32 functions as one of the coactivators for RARα-mediated transcription in acute promyelogenous leukemia (APL) cells, and thus TRIM32 may become a potentially therapeutic target for APL.

Lysosomal ceramide generated by acid sphingomyelinase triggers cytosolic cathepsin B-mediated degradation of X-linked inhibitor of apoptosis protein in natural killer/T lymphoma cell apoptosis

OpenAIRE

Taniguchi, M; Ogiso, H; Takeuchi, T; Kitatani, K; Umehara, H; Okazaki, T

2015-01-01

We previously reported that IL-2 deprivation induced acid sphingomyelinase-mediated (ASM-mediated) ceramide elevation and apoptosis in an NK/T lymphoma cell line KHYG-1. However, the molecular mechanism of ASM?ceramide-mediated apoptosis during IL-2 deprivation is poorly understood. Here, we showed that IL-2 deprivation induces caspase-dependent apoptosis characterized by phosphatidylserine externalization, caspase-8, -9, and -3 cleavage, and degradation of X-linked inhibitor of apoptosis pro...

The role of gamma-aminobutyric acid/glycinergic synaptic transmission in mediating bilirubin-induced hyperexcitation in developing auditory neurons.

Science.gov (United States)

Yin, Xin-Lu; Liang, Min; Shi, Hai-Bo; Wang, Lu-Yang; Li, Chun-Yan; Yin, Shan-Kai

2016-01-05

Hyperbilirubinemia is a common clinical phenomenon observed in human newborns. A high level of bilirubin can result in severe jaundice and bilirubin encephalopathy. However, the cellular mechanisms underlying bilirubin excitotoxicity are unclear. Our previous studies showed the action of gamma-aminobutyric acid (GABA)/glycine switches from excitatory to inhibitory during development in the ventral cochlear nucleus (VCN), one of the most sensitive auditory nuclei to bilirubin toxicity. In the present study, we investigated the roles of GABAA/glycine receptors in the induction of bilirubin hyperexcitation in early developing neurons. Using the patch clamp technique, GABAA/glycine receptor-mediated spontaneous inhibitory synaptic currents (sIPSCs) were recorded from bushy and stellate cells in acute brainstem slices from young mice (postnatal day 2-6). Bilirubin significantly increased the frequency of sIPSCs, and this effect was prevented by pretreatments of slices with either fast or slow Ca(2+) chelators BAPTA-AM and EGTA-AM suggesting that bilirubin can increase the release of GABA/glycine via Ca(2+)-dependent mechanisms. Using cell-attached recording configuration, we found that antagonists of GABAA and glycine receptors strongly attenuated spontaneous spiking firings in P2-6 neurons but produced opposite effect in P15-19 neurons. Furthermore, these antagonists reversed bilirubin-evoked hyperexcitability in P2-6 neurons, indicating that excitatory action of GABA/glycinergic transmission specifically contribute to bilirubin-induced hyperexcitability in the early stage of development. Our results suggest that bilirubin-induced enhancement of presynaptic release GABA/Glycine via Ca(2+)-dependent mechanisms may play a critical role in mediating neuronal hyperexcitation associated with jaundice, implicating potential new strategies for predicting, preventing, and treating bilirubin neurotoxicity. Copyright © 2015. Published by Elsevier Ireland Ltd.

4T1 Murine Mammary Carcinoma Cells Enhance Macrophage-Mediated Innate Inflammatory Responses.

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Laurence Madera

Full Text Available Tumor progression and the immune response are intricately linked. While it is known that cancers alter macrophage inflammatory responses to promote tumor progression, little is known regarding how cancers affect macrophage-dependent innate host defense. In this study, murine bone-marrow-derived macrophages (BMDM were exposed to murine carcinoma-conditioned media prior to assessment of the macrophage inflammatory response. BMDMs exposed to 4T1 mammary carcinoma-conditioned medium demonstrated enhanced production of pro-inflammatory cytokines tumor necrosis factor α, interleukin-6, and CCL2 in response to lipopolysaccharide (LPS while production of interleukin-10 remained unchanged. The increased LPS-induced production of pro-inflammatory cytokines was transient and correlated with enhanced cytokine production in response to other Toll-like receptor agonists, including peptidoglycan and flagellin. In addition, 4T1-conditioned BMDMs exhibited strengthened LPS-induced nitric oxide production and enhanced phagocytosis of Escherichia coli. 4T1-mediated augmentation of macrophage responses to LPS was partially dependent on the NFκB pathway, macrophage-colony stimulating factor, and actin polymerization, as well as the presence of 4T1-secreted extracellular vesicles. Furthermore, peritoneal macrophages obtained from 4T1 tumor-bearing mice displayed enhanced pro-inflammatory cytokine production in response to LPS. These results suggest that uptake of 4T1-secreted factors and actin-mediated ingestion of 4T1-secreted exosomes by macrophages cause a transient enhancement of innate inflammatory responses. Mammary carcinoma-mediated regulation of innate immunity may have significant implications for our understanding of host defense and cancer progression.

Salivary a-amylase protects enamel surface against acid induced softening

DEFF Research Database (Denmark)

Lazovic, Maja Bruvo; Moe, Dennis; Kirkeby, Svend

Objectives: Recently we have demonstrated individual differences in protection against acid-induced enamel softening offered by experimentally developed saliva pellicles. Although ethnicity seemed to be related to protection level, the saliva proteins responsible for the differences were not iden......Objectives: Recently we have demonstrated individual differences in protection against acid-induced enamel softening offered by experimentally developed saliva pellicles. Although ethnicity seemed to be related to protection level, the saliva proteins responsible for the differences were......, and one Chinese. After collection, saliva was dialysed and lyophilised and re-dissolved at 0.5% in Type I water. Next, four polished bovine enamel specimens were immersed into each sample under gentle and constant shaking for 12 hours. Last, specimens were exposed to an erosive challenge of pH 2.3 for 4......-TOF mass fingerprinting following trypsin digestion. Each persistent peak in the HPLC chromatograms was related to the protective effect against acid-induced enamel softening obtained by the corresponding saliva sample by multiple regression analysis. Results: One peak identified as a-amylase had...

Fatty acid synthase as a factor required for exercise-induced cognitive enhancement and dentate gyrus cellular proliferation.

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Nataliya E Chorna

Full Text Available Voluntary running is a robust inducer of adult hippocampal neurogenesis. Given that fatty acid synthase (FASN, the key enzyme for de novo fatty acid biosynthesis, is critically involved in proliferation of embryonic and adult neural stem cells, we hypothesized that FASN could mediate both exercise-induced cell proliferation in the subgranular zone (SGZ of the dentate gyrus (DG and enhancement of spatial learning and memory. In 20 week-old male mice, voluntary running-induced hippocampal-specific upregulation of FASN was accompanied also by hippocampal-specific accumulation of palmitate and stearate saturated fatty acids. In experiments addressing the functional role of FASN in our experimental model, chronic intracerebroventricular (i.c.v. microinfusions of C75, an irreversible FASN inhibitor, and significantly impaired exercise-mediated improvements in spatial learning and memory in the Barnes maze. Unlike the vehicle-injected mice, the C75 group adopted a non-spatial serial escape strategy and displayed delayed escape latencies during acquisition and memory tests. Furthermore, pharmacologic blockade of FASN function with C75 resulted in a significant reduction, compared to vehicle treated controls, of the number of proliferative cells in the DG of running mice as measured by immunoreactive to Ki-67 in the SGZ. Taken together, our data suggest that FASN plays an important role in exercise-mediated cognitive enhancement, which might be associated to its role in modulating exercise-induced stimulation of neurogenesis.

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

International Nuclear Information System (INIS)

Luo, Ying; Li, Shu-Jun; Yang, Jian; Qiu, Yuan-Zhen; Chen, Fang-Ping

2013-01-01

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

Ozone-Induced Hypertussive Responses in Rabbits and Guinea Pigs

Science.gov (United States)

Clay, Emlyn; Patacchini, Riccardo; Trevisani, Marcello; Preti, Delia; Branà, Maria Pia; Spina, Domenico

2016-01-01

Cough remains a major unmet clinical need, and preclinical animal models are not predictive for new antitussive agents. We have investigated the mechanisms and pharmacological sensitivity of ozone-induced hypertussive responses in rabbits and guinea pigs. Ozone induced a significant increase in cough frequency and a decrease in time to first cough to inhaled citric acid in both conscious guinea pigs and rabbits. This response was inhibited by the established antitussive drugs codeine and levodropropizine. In contrast to the guinea pig, hypertussive responses in the rabbit were not inhibited by bronchodilator drugs (β2 agonists or muscarinic receptor antagonists), suggesting that the observed hypertussive state was not secondary to bronchoconstriction in this species. The ozone-induced hypertussive response in the rabbit was inhibited by chronic pretreatment with capsaicin, suggestive of a sensitization of airway sensory nerve fibers. However, we could find no evidence for a role of TRPA1 in this response, suggesting that ozone was not sensitizing airway sensory nerves via activation of this receptor. Whereas the ozone-induced hypertussive response was accompanied by a significant influx of neutrophils into the airway, the hypertussive response was not inhibited by the anti-inflammatory phosphodiesterase 4 inhibitor roflumilast at a dose that clearly exhibited anti-inflammatory activity. In summary, our results suggest that ozone-induced hypertussive responses to citric acid may provide a useful model for the investigation of novel drugs for the treatment of cough, but some important differences were noted between the two species with respect to sensitivity to bronchodilator drugs. PMID:26837703

Fatty Acid Mixtures from Nigella sativa Protects PC12 Cells from Oxidative Stress and Apoptosis Induced by Doxorubicin

Directory of Open Access Journals (Sweden)

Leila Hosseinzadeh

2018-03-01

Full Text Available Background: Fatty acids (FAs, the key structural elements of dietary lipids, are notable in the nutritional value of plants. Black cumin, a popular anti-inflammatory and antioxidant food seasoning, contains nonpolar constituents such as FAs. Methods: Seeds were extracted using hexane and their cytoprotective activity was assessed against doxorubicin (DOX-mediated oxidative stress and apoptosis in PC12 cell line. Results: In spite of the cellular death induced by DOX toward PC12 cells, bioassay-guided purification showed that pretreatment with FAs mixtures (24h attenuated DOX-mediated apoptosis, which could be attributed to the inhibited caspase 3 activity and enhanced mitochondrial membrane potential. Palmitic acid, caprylic acid and oleic acid each 1/3 in the mixture, also suppressed DOX-induced ROS generation. Conclusion: Our observation indicated that the subtoxic concentration of FAs from Nigella sativa could effectively protect the cells against oxidative stress, due to their antioxidant activity, and could be regarded as a dietary supplement.

C-terminal of human histamine H1 receptors regulates their agonist-induced clathrin-mediated internalization and G-protein signaling.

Science.gov (United States)

Hishinuma, Shigeru; Nozawa, Hiroki; Akatsu, Chizuru; Shoji, Masaru

2016-11-01

It has been suggested that the agonist-induced internalization of G-protein-coupled receptors from the cell surface into intracellular compartments regulates cellular responsiveness. We previously reported that G q/11 -protein-coupled human histamine H 1 receptors internalized via clathrin-dependent mechanisms upon stimulation with histamine. However, the molecular determinants of H 1 receptors responsible for agonist-induced internalization remain unclear. In this study, we evaluated the roles of the intracellular C-terminal of human histamine H 1 receptors tagged with hemagglutinin (HA) at the N-terminal in histamine-induced internalization in Chinese hamster ovary cells. The histamine-induced internalization was evaluated by the receptor binding assay with [ 3 H]mepyramine and confocal immunofluorescence microscopy with an anti-HA antibody. We found that histamine-induced internalization was inhibited under hypertonic conditions or by pitstop, a clathrin terminal domain inhibitor, but not by filipin or nystatin, disruptors of the caveolar structure and function. The histamine-induced internalization was also inhibited by truncation of a single amino acid, Ser487, located at the end of the intracellular C-terminal of H 1 receptors, but not by its mutation to alanine. In contrast, the receptor-G-protein coupling, which was evaluated by histamine-induced accumulation of [ 3 H]inositol phosphates, was potentiated by truncation of Ser487, but was lost by its mutation to alanine. These results suggest that the intracellular C-terminal of human H 1 receptors, which only comprises 17 amino acids (Cys471-Ser487), plays crucial roles in both clathrin-dependent internalization of H 1 receptors and G-protein signaling, in which truncation of Ser487 and its mutation to alanine are revealed to result in biased signaling toward activation of G-proteins and clathrin-mediated internalization, respectively. © 2016 International Society for Neurochemistry.

9-cis-retinoic acid represses estrogen-induced expression of the very low density apolipoprotein II gene.

Science.gov (United States)

Schippers, I J; Kloppenburg, M; Snippe, L; Ab, G

1994-11-01

The chicken very low density apolipoprotein II (apoVLDLII) gene is estrogen-inducible and specifically expressed in liver. We examined the possible involvement of the retinoid X receptor (RXR) and its ligand 9-cis-retinoic acid (9-cis-RA) in the activation of the apoVLDLII promoter. We first concentrated on a potential RXR recognition site, which deviates at only one position from a perfect direct A/GGGTCA repeat spaced by one nucleotide (DR-1) and was earlier identified as a common HNF-4/COUP-TF recognition site. However, band shift analysis revealed that this imperfect DR-1 motif does not interact with RXR alpha-homodimers. In accordance with this observation we found that this regulatory element does not mediate transactivation through RXR alpha in the presence of 9-cis-RA. However, our experiments revealed another, unexpected, effect of 9-cis-RA. Instead of stimulating, 9-cis-RA attenuated estrogen-induced expression of transfected estrogen-responsive VLDL-CAT reporter plasmids. This repression appeared to take place through the main estrogen response element (ERE) of the gene. Importantly, 9-cis-RA also strongly repressed the estrogen-induced expression of the endogenous apoVLDLII gene in cultured chicken hepatoma cells.

Determination of proteins induced in response to jasmonic acid and salicylic acid in resistant and susceptible cultivars of tomato.

Science.gov (United States)

Afroz, Amber; Khan, Muhammad Rashid; Komatsu, Setsuko

2010-07-01

Jasmonic acid (JA) and salicylic acid (SA) are signaling molecules that play key roles in the regulation of metabolic processes, reproduction, and defense against pathogens. The proteomics approach was used to identify proteins that are induced by JA and SA in the tomato cultivars Roma and Pant Bahr, which are susceptible and resistant to bacterial wilt, respectively. Threonine deaminase and leucine amino peptidase were upregulated, and ribulose-1,5-bisphosphate carboxylase/oxygenase small chain was downregulated by time-course application of JA. Translationally controlled tumor protein was upregulated by time-course application of SA. Protein disulfide isomerase was upregulated by application of either JA or SA. Proteins related to defense, energy, and protein destination/storage are suspected to be responsible for the susceptibility or resistance of the cultivars. Furthermore, in Roma, iron ABC transporter was upregulated by JA and down-regulated by SA. Iron ABC transporter plays a part in the signal transduction of both JA and SA in cultivars of tomato that are resistant to bacterial wilt.

Fatty acid-amino acid conjugates are essential for systemic activation of salicylic acid-induced protein kinase and accumulation of jasmonic acid in Nicotiana attenuata.

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Hettenhausen, Christian; Heinrich, Maria; Baldwin, Ian T; Wu, Jianqiang

2014-11-28

Herbivory induces the activation of mitogen-activated protein kinases (MAPKs), the accumulation of jasmonates and defensive metabolites in damaged leaves and in distal undamaged leaves. Previous studies mainly focused on individual responses and a limited number of systemic leaves, and more research is needed for a better understanding of how different plant parts respond to herbivory. In the wild tobacco Nicotiana attenuata, FACs (fatty acid-amino acid conjugates) in Manduca sexta oral secretions (OS) are the major elicitors that induce herbivory-specific signaling but their role in systemic signaling is largely unknown. Here, we show that simulated herbivory (adding M. sexta OS to fresh wounds) dramatically increased SIPK (salicylic acid-induced protein kinase) activity and jasmonic acid (JA) levels in damaged leaves and in certain (but not all) undamaged systemic leaves, whereas wounding alone had no detectable systemic effects; importantly, FACs and wounding are both required for activating these systemic responses. In contrast to the activation of SIPK and elevation of JA in specific systemic leaves, increases in the activity of an important anti-herbivore defense, trypsin proteinase inhibitor (TPI), were observed in all systemic leaves after simulated herbivory, suggesting that systemic TPI induction does not require SIPK activation and JA increases. Leaf ablation experiments demonstrated that within 10 minutes after simulated herbivory, a signal (or signals) was produced and transported out of the treated leaves, and subsequently activated systemic responses. Our results reveal that N. attenuata specifically recognizes herbivore-derived FACs in damaged leaves and rapidly send out a long-distance signal to phylotactically connected leaves to activate MAPK and JA signaling, and we propose that FACs that penetrated into wounds rapidly induce the production of another long-distance signal(s) which travels to all systemic leaves and activates TPI defense.

The RAB2B-GARIL5 Complex Promotes Cytosolic DNA-Induced Innate Immune Responses.

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Takahama, Michihiro; Fukuda, Mitsunori; Ohbayashi, Norihiko; Kozaki, Tatsuya; Misawa, Takuma; Okamoto, Toru; Matsuura, Yoshiharu; Akira, Shizuo; Saitoh, Tatsuya

2017-09-19

Cyclic GMP-AMP synthase (cGAS) is a cytosolic DNA sensor that induces the IFN antiviral response. However, the regulatory mechanisms that mediate cGAS-triggered signaling have not been fully explored. Here, we show the involvement of a small GTPase, RAB2B, and its effector protein, Golgi-associated RAB2B interactor-like 5 (GARIL5), in the cGAS-mediated IFN response. RAB2B-deficiency affects the IFN response induced by cytosolic DNA. Consistent with this, RAB2B deficiency enhances replication of vaccinia virus, a DNA virus. After DNA stimulation, RAB2B colocalizes with stimulator of interferon genes (STING), the downstream signal mediator of cGAS, on the Golgi apparatus. The GTP-binding activity of RAB2B is required for its localization on the Golgi apparatus and for recruitment of GARIL5. GARIL5 deficiency also affects the IFN response induced by cytosolic DNA and enhances replication of vaccinia virus. These findings indicate that the RAB2B-GARIL5 complex promotes IFN responses against DNA viruses by regulating the cGAS-STING signaling axis. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

The RAB2B-GARIL5 Complex Promotes Cytosolic DNA-Induced Innate Immune Responses

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Michihiro Takahama

2017-09-01

Full Text Available Cyclic GMP-AMP synthase (cGAS is a cytosolic DNA sensor that induces the IFN antiviral response. However, the regulatory mechanisms that mediate cGAS-triggered signaling have not been fully explored. Here, we show the involvement of a small GTPase, RAB2B, and its effector protein, Golgi-associated RAB2B interactor-like 5 (GARIL5, in the cGAS-mediated IFN response. RAB2B-deficiency affects the IFN response induced by cytosolic DNA. Consistent with this, RAB2B deficiency enhances replication of vaccinia virus, a DNA virus. After DNA stimulation, RAB2B colocalizes with stimulator of interferon genes (STING, the downstream signal mediator of cGAS, on the Golgi apparatus. The GTP-binding activity of RAB2B is required for its localization on the Golgi apparatus and for recruitment of GARIL5. GARIL5 deficiency also affects the IFN response induced by cytosolic DNA and enhances replication of vaccinia virus. These findings indicate that the RAB2B-GARIL5 complex promotes IFN responses against DNA viruses by regulating the cGAS-STING signaling axis.

Intercellular and intracellular signaling pathways mediating ionizing radiation-induced bystander effects

International Nuclear Information System (INIS)

Hamada, Nobuyuki; Hara, Takamitsu; Kobayashi, Yasuhiko; Matsumoto, Hideki

2007-01-01

A rapidly growing body of experimental evidence indicates that ionizing radiation induces biological effects in non-irradiated bystander cells that have received signals from adjacent or distant irradiated cells. This phenomenon, which has been termed the ionizing radiation-induced bystander effect, challenges the long-standing paradigm that radiation traversal through the nucleus of a cell is a prerequisite to elicit genetic damage or a biological response. Bystander effects have been observed in a number of experimental systems, and cells whose nucleus or cytoplasm is irradiated exert bystander responses. Bystander cells manifest a multitude of biological consequences, such as genetic and epigenetic changes, alterations in gene expression, activation of signal transduction pathways, and delayed effects in their progeny. Several mediating mechanisms have been proposed. These involve gap junction-mediated intercellular communication, secreted soluble factors, oxidative metabolism, plasma membrane-bound lipid rafts, and calcium fluxes. This paper reviews briefly the current knowledge of the bystander effect with a focus on proposed mechanisms. The potential benefit of bystander effects to cancer radiotherapy will also be discussed. (author)

Fenspiride inhibits histamine-induced responses in a lung epithelial cell line.

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Quartulli, F; Pinelli, E; Broué-Chabbert, A; Gossart, S; Girard, V; Pipy, B

1998-05-08

Using the human lung epithelial WI26VA4 cell line, we investigated the capacity of fenspiride, an anti-inflammatory drug with anti-bronchoconstrictor properties, to interfere with histamine-induced intracellular Ca2+ increase and eicosanoid formation. Histamine and a histamine H1 receptor agonist elicited a rapid and transient intracellular Ca2+ increase (0-60 s) in fluo 3-loaded WI26VA4 cells. This response was antagonized by the histamine H1 receptor antagonist, diphenhydramine, the histamine H2 receptor antagonist, cimetidine, having no effect. Fenspiride (10(-7)-10(-5) M) inhibited the histamine H1 receptor-induced Ca2+ increase. In addition, histamine induced a biphasic increase in arachidonic acid release. The initial rise (0-30 s), a rapid and transient arachidonic acid release, was responsible for the histamine-induced intracellular Ca2+ increase. In the second phase release (15-60 min), a sustained arachidonic acid release appeared to be associated with the formation of cyclooxygenase and lipoxygenase metabolites. Fenspiride (10(-5) M) abolished both phases of histamine-induced arachidonic acid release. These results suggest that anti-inflammatory and antibronchoconstrictor properties of fenspiride may result from the inhibition of these effects of histamine.

Apigenin reduce lipoteichoic acid-induced inflammatory response in rat cardiomyoblast cells.

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Gutiérrez-Venegas, Gloria; González-Rosas, Zeltzin

2017-02-01

Infective endocarditis is caused by Streptococcus sanguinis present in dental plaque, which can induce inflammatory responses in the endocardium. The present study depicts research on the properties of apigenin in embryonic mouse heart cells (H9c2) treated with lipoteichoic acid (LTA) obtained from S. sanguinis. Interleukin-1β and cyclooxygenase (COX)-2 expression were detected by reverse transcriptase polymerase chain reaction. In addition, western blot assays and immuno-fluorescence staining were used to assess translocation of nuclear factor kappa beta (NF-κB), degradation of IκB, as well as activity of the mitogen activated protein kinases: extracellular signal-regulated kinase (ERK)1/2, p38, and c-Jun N-terminal kinase (JNK). Effect of apigenin on cell viability was equally assessed in other experimental series. Our results showed that apigenin blocked activation of ERK, JNK, and p38 in cardiomyocytes treated with LTA in a dose-dependent fashion. Moreover, apigenin showed no cytotoxic effects; it blocked NF-κB translocation and IκB degradation. Our findings suggested that apigenin possessed potential value in the treatment of infectious endocarditis.

Endomorphins potentiate acid-sensing ion channel currents and enhance the lactic acid-mediated increase in arterial blood pressure: effects amplified in hindlimb ischaemia.

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Farrag, Mohamed; Drobish, Julie K; Puhl, Henry L; Kim, Joyce S; Herold, Paul B; Kaufman, Marc P; Ruiz-Velasco, Victor

2017-12-01

Chronic limb ischaemia, characterized by inflammatory mediator release and a low extracellular pH, leads to acid-sensing ion channel (ASIC) activation and reflexively increases mean arterial pressure; endomorphin release is also increased under inflammatory conditions. We examined the modulation of ASIC currents by endomorphins in sensory neurons from rats with freely perfused and ligated femoral arteries: peripheral artery disease (PAD) model. Endomorphins potentiated sustained ASIC currents in both groups of dorsal root ganglion neurons, independent of mu opioid receptor stimulation or G protein activation. Intra-arterial administration of lactic acid (to simulate exercising muscle and evoke a pressor reflex), endomorphin-2 and naloxone resulted in a significantly greater pressor response than lactic acid alone, while administration of APETx2 inhibited endomorphin's enhancing effect in both groups. These results suggest a novel role for endomorphins in modulating ASIC function to effect lactic acid-mediated reflex increase in arterial pressure in patients with PAD. Chronic muscle ischaemia leads to accumulation of lactic acid and other inflammatory mediators with a subsequent drop in interstitial pH. Acid-sensing ion channels (ASICs), expressed in thin muscle afferents, sense the decrease in pH and evoke a pressor reflex known to increase mean arterial pressure. The naturally occurring endomorphins are also released by primary afferents under ischaemic conditions. We examined whether high affinity mu opioid receptor (MOR) agonists, endomorphin-1 (E-1) and -2 (E-2), modulate ASIC currents and the lactic acid-mediated pressor reflex. In rat dorsal root ganglion (DRG) neurons, exposure to E-2 in acidic solutions significantly potentiated ASIC currents when compared to acidic solutions alone. The potentiation was significantly greater in DRG neurons isolated from rats whose femoral arteries were ligated for 72 h. Sustained ASIC current potentiation was also observed

Virus-induced down-regulation of GmERA1A and GmERA1B genes enhances the stomatal response to abscisic acid and drought resistance in soybean.

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Takuya Ogata

Full Text Available Drought is a major threat to global soybean production. The limited transformation potential and polyploid nature of soybean have hindered functional analysis of soybean genes. Previous research has implicated farnesylation in the plant's response to abscisic acid (ABA and drought tolerance. We therefore used virus-induced gene silencing (VIGS to evaluate farnesyltransferase genes, GmERA1A and GmERA1B (Glycine max Enhanced Response to ABA1-A and -B, as potential targets for increasing drought resistance in soybean. Apple latent spherical virus (ALSV-mediated GmERA1-down-regulated soybean leaves displayed an enhanced stomatal response to ABA and reduced water loss and wilting under dehydration conditions, suggesting that GmERA1A and GmERA1B negatively regulate ABA signaling in soybean guard cells. The findings provide evidence that the ALSV-VIGS system, which bypasses the need to generate transgenic plants, is a useful tool for analyzing gene function using only a single down-regulated leaf. Thus, the ALSV-VIGS system could constitute part of a next-generation molecular breeding pipeline to accelerate drought resistance breeding in soybean.

Selective activation of human heat shock gene transcription by nitrosourea antitumor drugs mediated by isocyanate-induced damage and activation of heat shock transcription factor.

Science.gov (United States)

Kroes, R A; Abravaya, K; Seidenfeld, J; Morimoto, R I

1991-01-01

Treatment of cultured human tumor cells with the chloroethylnitrosourea antitumor drug 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) selectively induces transcription and protein synthesis of a subset of the human heat shock or stress-induced genes (HSP90 and HSP70) with little effect on other stress genes or on expression of the c-fos, c-myc, or beta-actin genes. The active component of BCNU and related compounds appears to be the isocyanate moiety that causes carbamoylation of proteins and nucleic acids. Transcriptional activation of the human HSP70 gene by BCNU is dependent on the heat shock element and correlates with the level of heat shock transcription factor and its binding to the heat shock element in vivo. Unlike activation by heat or heavy metals, BCNU-mediated activation is strongly dependent upon new protein synthesis. This suggests that BCNU-induced, isocyanate-mediated damage to newly synthesized protein(s) may be responsible for activation of the heat shock transcription factor and increased transcription of the HSP90 and HSP70 genes. Images PMID:2052560

Variation in copper effects on kairomone-mediated responses in Daphnia pulicaria.

Science.gov (United States)

DeMille, C M; Arnott, S E; Pyle, G G

2016-04-01

Chemical signals play an integral role in many predator-prey relationships but their effectiveness can be altered by environmental conditions. Prey species can detect predator kairomones, which induce anti-predator defenses. An example of this predator-prey relationship exists between Daphnia spp. and Chaoborus spp.; however, when living in water contaminated with low concentrations of copper (Cu) Daphnia can fail to respond to Chaoborus kairomone and, in turn, become more susceptible to predation. This has implications for Daphnia living in regions with Cu contamination, such as areas where mining activity has resulted in increased levels of metals in the surrounding lakes. We examined kairomone-mediated responses of multiple Daphnia pulicaria clones obtained from 8 lakes in Ontario, Canada, in the absence and presence of environmentally-relevant Cu concentrations. Life history traits and morphological anti-predator defenses were assessed using neonates collected from mothers that were exposed to kairomone and Cu treatments. We found that kairomone-mediated responses and Cu-tolerance varied among D. pulicaria clones. Clones exposed to kairomone, in the absence of Cu additions, had diverse responses, including larger neonates, delayed reproduction, or altered brood size relative to no-kairomone controls. These kairomone-induced responses act as antipredator defense strategies against Chaoborus by preventing predation or stabilizing population growth. When exposed to Cu, two clones were able to respond to kairomone, while four clones no longer induced a response to kairomone. This variation in non-lethal effects of Cu on aquatic organisms suggests that toxicity tests should incorporate multiple genotypes and include predator-prey interactions. Copyright © 2016 Elsevier Inc. All rights reserved.

Phleum pratense pollen starch granules induce humoral and cell-mediated immune responses in a rat model of allergy.

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Motta, A; Peltre, G; Dormans, J A M A; Withagen, C E T; Lacroix, G; Bois, F; Steerenberg, P A

2004-02-01

Timothy grass (Phleum pratense) pollen allergens are an important cause of allergic symptoms. However, pollen grains are too large to penetrate the deeper airways. Grass pollen is known to release allergen-bearing starch granules (SG) upon contact with water. These granules can create an inhalable allergenic aerosol capable of triggering an early asthmatic response and are implicated in thunderstorm-associated asthma. We studied the humoral (IgE) and bronchial lymph node cells reactivities to SG from timothy grass pollen in pollen-sensitized rats. Brown-Norway rats were sensitized (day 0) and challenged (day 21) intratracheally with intact pollen and kept immunized by pollen intranasal instillation by 4 weeks intervals during 3 months. Blood and bronchial lymph nodes were collected 7 days after the last intranasal challenge. SG were purified from fresh timothy grass pollen using 5 microm mesh filters. To determine the humoral response (IgE) to SG, we developed an original ELISA inhibition test, based on competition between pollen allergens and purified SG. The cell-mediated response to SG in the bronchial lymph node cells was determined by measuring the uptake of [3H]thymidine in a proliferation assay. An antibody response to SG was induced, and purified SG were able to inhibit the IgE ELISA absorbance by 45%. Pollen extract and intact pollen gave inhibitions of 55% and 52%, respectively. A cell-mediated response was also found, as pollen extract, intact pollen and SG triggered proliferation of bronchial lymph node cells. It was confirmed that timothy grass pollen contains allergen-loaded SG, which are released upon contact with water. These granules were shown to be recognized by pollen-sensitized rats sera and to trigger lymph node cell proliferation in these rats. These data provide new arguments supporting the implication of grass pollen SG in allergic asthma.

Therapeutic Applicability of Anti-Inflammatory and Proresolving Polyunsaturated Fatty Acid-Derived Lipid Mediators

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Gerard L. Bannenberg

2010-01-01

Full Text Available The enzymatic oxygenation of polyunsaturated fatty acids by lipoxygenases and cyclo-oxygenases is a resourceful mode of formation of specific autacoids that regulate the extent and pace of the inflammatory response. Arachidonate-derived eicosanoids, such as lipoxin A4, prostaglandin (PGD2, PGF2α, PGE2, and PGD2-derived cyclopentenones exert specific roles in counter-regulating inflammation and turning on resolution. Recently recognized classes of autacoids derived from long-chain ω-3 polyunsaturated fatty acids, the E- and D-series resolvins, protectin D1, and maresin 1, act as specialized mediators to dampen inflammation actively, afford tissue protection, stimulate host defense, and activate resolution. It is held that counter-regulatory lipid mediators and the specific molecular pathways activated by such endogenous agonists may be suitable for pharmacological use in the treatment of inflammatory disease. The anti-inflammatory drug aspirin is a striking example of a drug that is able to act in such a manner, namely through triggering the formation of 15-epi-lipoxin A4 and aspirin-triggered resolvins. Different aspects of the therapeutic applicability of lipid mediators have been addressed here, and indicate that the development of innovative pharmacotherapy based on anti-inflammatory and proresolution lipid mediators presents novel prospects for the treatment of inflammatory disease.

Gender difference following high cholesterol diet induced renal injury and the protective role of rutin and ascorbic acid combination in Wistar albino rats

Science.gov (United States)

2012-01-01

Background An increased interest is given to the impact of high fat diet on health worldwide. Abnormalities in lipid metabolism induced by high cholesterol diet (HCD) were reported to exacerbate renal diseases via oxidative stress pathways. Rutin and ascorbic acid showed a protective role against oxidative stress-mediated diseases. Furthermore, both lipid metabolism and tissue response to oxidative stress damage was found to vary according to animal gender. Thus, the objective of this work was to examine possible gender-related differences and the possible protective effects of rutin and ascorbic acid supplementation on high cholesterol diet induced nephrotoxicity. Methods 96 young male and female Wistar albino rats were used. HCD supplemented animals were treated with rutin alone or in combination with ascorbic acid for 6 weeks. Creatinine plasma level was estimated. Furthermore, kidney levels of nucleic acids, total protein, malondialdehyde (MDA), reduced glutathione (GSH), total cholesterol, and triglycerides were determined. Finally, kidney tissues were used for histopathological examination. Results HCD supplementation decreased kidney level of nucleic acids, which was more prominent in female animals. Both vitamin combination significantly attenuated HCD induced decrease in nucleic acids. Moreover, kidney level of MDA was significantly altered by HCD in both genders, which was inhibited by rutin and ascorbic acid alone or in combination in male groups and by both vitamins in female groups. There was a reduction in kidney level of GSH by HCD, especially in male groups, which was attenuated by rutin and ascorbic acid combination. Kidney levels of total cholesterol and triglycerides were significantly increased by HCD supplementation in both genders. Coadministration with rutin and/or ascorbic acid protected from such increase, which was more obvious in both vitamins combination. Histopathological investigation supported vitamins protective effect, which was

Gender difference following high cholesterol diet induced renal injury and the protective role of rutin and ascorbic acid combination in Wistar albino rats.

Science.gov (United States)

Al-Rejaie, Salim Salih; Abuohashish, Hatem Mustafa; Alkhamees, Osama Abdelrahman; Aleisa, Abdulaziz Mohammed; Alroujayee, Abdulaziz S

2012-03-16

An increased interest is given to the impact of high fat diet on health worldwide. Abnormalities in lipid metabolism induced by high cholesterol diet (HCD) were reported to exacerbate renal diseases via oxidative stress pathways. Rutin and ascorbic acid showed a protective role against oxidative stress-mediated diseases. Furthermore, both lipid metabolism and tissue response to oxidative stress damage was found to vary according to animal gender. Thus, the objective of this work was to examine possible gender-related differences and the possible protective effects of rutin and ascorbic acid supplementation on high cholesterol diet induced nephrotoxicity. 96 young male and female Wistar albino rats were used. HCD supplemented animals were treated with rutin alone or in combination with ascorbic acid for 6 weeks. Creatinine plasma level was estimated. Furthermore, kidney levels of nucleic acids, total protein, malondialdehyde (MDA), reduced glutathione (GSH), total cholesterol, and triglycerides were determined. Finally, kidney tissues were used for histopathological examination. HCD supplementation decreased kidney level of nucleic acids, which was more prominent in female animals. Both vitamin combination significantly attenuated HCD induced decrease in nucleic acids. Moreover, kidney level of MDA was significantly altered by HCD in both genders, which was inhibited by rutin and ascorbic acid alone or in combination in male groups and by both vitamins in female groups. There was a reduction in kidney level of GSH by HCD, especially in male groups, which was attenuated by rutin and ascorbic acid combination. Kidney levels of total cholesterol and triglycerides were significantly increased by HCD supplementation in both genders. Coadministration with rutin and/or ascorbic acid protected from such increase, which was more obvious in both vitamins combination. Histopathological investigation supported vitamins protective effect, which was more prominent in male

Gender difference following high cholesterol diet induced renal injury and the protective role of rutin and ascorbic acid combination in Wistar albino rats

Directory of Open Access Journals (Sweden)

Al-Rejaie Salim

2012-03-01

Full Text Available Abstract Background An increased interest is given to the impact of high fat diet on health worldwide. Abnormalities in lipid metabolism induced by high cholesterol diet (HCD were reported to exacerbate renal diseases via oxidative stress pathways. Rutin and ascorbic acid showed a protective role against oxidative stress-mediated diseases. Furthermore, both lipid metabolism and tissue response to oxidative stress damage was found to vary according to animal gender. Thus, the objective of this work was to examine possible gender-related differences and the possible protective effects of rutin and ascorbic acid supplementation on high cholesterol diet induced nephrotoxicity. Methods 96 young male and female Wistar albino rats were used. HCD supplemented animals were treated with rutin alone or in combination with ascorbic acid for 6 weeks. Creatinine plasma level was estimated. Furthermore, kidney levels of nucleic acids, total protein, malondialdehyde (MDA, reduced glutathione (GSH, total cholesterol, and triglycerides were determined. Finally, kidney tissues were used for histopathological examination. Results HCD supplementation decreased kidney level of nucleic acids, which was more prominent in female animals. Both vitamin combination significantly attenuated HCD induced decrease in nucleic acids. Moreover, kidney level of MDA was significantly altered by HCD in both genders, which was inhibited by rutin and ascorbic acid alone or in combination in male groups and by both vitamins in female groups. There was a reduction in kidney level of GSH by HCD, especially in male groups, which was attenuated by rutin and ascorbic acid combination. Kidney levels of total cholesterol and triglycerides were significantly increased by HCD supplementation in both genders. Coadministration with rutin and/or ascorbic acid protected from such increase, which was more obvious in both vitamins combination. Histopathological investigation supported vitamins

Neurogenic mediators contribute to local edema induced by Micrurus lemniscatus venom

Science.gov (United States)

2017-01-01

Background/Aims Micrurus is one of the four snake genera of medical importance in Brazil. Coral snakes have a broad geographic distribution from the southern United States to Argentina. Micrurine envenomation is characterized by neurotoxic symptoms leading to dyspnea and death. Moreover, various local manifestations, including edema formation, have been described in patients bitten by different species of Micrurus. Thus, we investigated the ability of Micrurus lemniscatus venom (MLV) to induce local edema. We also explored mechanisms underlying this effect, focusing on participation of neuropeptides and mast cells. Methodology/Principal findings Intraplantar injection of MLV (1–10 μg/paw) in rats caused dose- and time-dependent edema with a peak between 15 min and 1 h after injection. MLV also induced degranulation of peritoneal mast cells (MCs). MC depletion by compound 48/80 markedly reduced MLV-induced edema. Pre-treatment (30 min) of rats with either promethazine a histamine H1 receptor antagonist or methysergide, a nonselective 5-HT receptor antagonist, reduced MLV-induced edema. However, neither thioperamide, a histamine H3/H4 receptor antagonist, nor co-injection of MLV with HOE-140, a BK2 receptor antagonist, altered the response. Depletion of neuropeptides by capsaicin or treatment of animals with NK1- and NK2-receptor antagonists (SR 140333 and SR 48968, respectively) markedly reduced MLV-induced edema. Conclusions/Significance In conclusion, MLV induces paw edema in rats by mechanisms involving activation of mast cells and substance P-releasing sensory C-fibers. Tachykinins NKA and NKB, histamine, and serotonin are major mediators of the MLV-induced edematogenic response. Targeting mast cell- and sensory C-fiber-derived mediators should be considered as potential therapeutic approaches to interrupt development of local edema induced by Micrurus venoms. PMID:29161255

Neurogenic mediators contribute to local edema induced by Micrurus lemniscatus venom.

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Luciana Lyra Casais-E-Silva

2017-11-01

Full Text Available Micrurus is one of the four snake genera of medical importance in Brazil. Coral snakes have a broad geographic distribution from the southern United States to Argentina. Micrurine envenomation is characterized by neurotoxic symptoms leading to dyspnea and death. Moreover, various local manifestations, including edema formation, have been described in patients bitten by different species of Micrurus. Thus, we investigated the ability of Micrurus lemniscatus venom (MLV to induce local edema. We also explored mechanisms underlying this effect, focusing on participation of neuropeptides and mast cells.Intraplantar injection of MLV (1-10 μg/paw in rats caused dose- and time-dependent edema with a peak between 15 min and 1 h after injection. MLV also induced degranulation of peritoneal mast cells (MCs. MC depletion by compound 48/80 markedly reduced MLV-induced edema. Pre-treatment (30 min of rats with either promethazine a histamine H1 receptor antagonist or methysergide, a nonselective 5-HT receptor antagonist, reduced MLV-induced edema. However, neither thioperamide, a histamine H3/H4 receptor antagonist, nor co-injection of MLV with HOE-140, a BK2 receptor antagonist, altered the response. Depletion of neuropeptides by capsaicin or treatment of animals with NK1- and NK2-receptor antagonists (SR 140333 and SR 48968, respectively markedly reduced MLV-induced edema.In conclusion, MLV induces paw edema in rats by mechanisms involving activation of mast cells and substance P-releasing sensory C-fibers. Tachykinins NKA and NKB, histamine, and serotonin are major mediators of the MLV-induced edematogenic response. Targeting mast cell- and sensory C-fiber-derived mediators should be considered as potential therapeutic approaches to interrupt development of local edema induced by Micrurus venoms.

HMGB1-mediated DNA bending: Distinct roles in increasing p53 binding to DNA and the transactivation of p53-responsive gene promoters.

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Štros, Michal; Kučírek, Martin; Sani, Soodabeh Abbasi; Polanská, Eva

2018-03-01

HMGB1 is a chromatin-associated protein that has been implicated in many important biological processes such as transcription, recombination, DNA repair, and genome stability. These functions include the enhancement of binding of a number of transcription factors, including the tumor suppressor protein p53, to their specific DNA-binding sites. HMGB1 is composed of two highly conserved HMG boxes, linked to an intrinsically disordered acidic C-terminal tail. Previous reports have suggested that the ability of HMGB1 to bend DNA may explain the in vitro HMGB1-mediated increase in sequence-specific DNA binding by p53. The aim of this study was to reinvestigate the importance of HMGB1-induced DNA bending in relationship to the ability of the protein to promote the specific binding of p53 to short DNA duplexes in vitro, and to transactivate two major p53-regulated human genes: Mdm2 and p21/WAF1. Using a number of HMGB1 mutants, we report that the HMGB1-mediated increase in sequence-specific p53 binding to DNA duplexes in vitro depends very little on HMGB1-mediated DNA bending. The presence of the acidic C-terminal tail of HMGB1 and/or the oxidation of the protein can reduce the HMGB1-mediated p53 binding. Interestingly, the induction of transactivation of p53-responsive gene promoters by HMGB1 requires both the ability of the protein to bend DNA and the acidic C-terminal tail, and is promoter-specific. We propose that the efficient transactivation of p53-responsive gene promoters by HMGB1 depends on complex events, rather than solely on the promotion of p53 binding to its DNA cognate sites. Copyright © 2018 Elsevier B.V. All rights reserved.

Neutrophils and the calcium-binding protein MRP-14 mediate carrageenan-induced antinociception in mice

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Rosana L. Pagano

2002-01-01

Full Text Available Background: We have previously shown that the calcium-binding protein MRP-14 secreted by neutrophils mediates the antinociceptive response in an acute inflammatory model induced by the intraperitoneal injection of glycogen in mice.

Involvement of ethylene in gibberellic acid-induced sulfur assimilation, photosynthetic responses, and alleviation of cadmium stress in mustard.

Science.gov (United States)

Masood, Asim; Khan, M Iqbal R; Fatma, Mehar; Asgher, Mohd; Per, Tasir S; Khan, Nafees A

2016-07-01

The role of gibberellic acid (GA) or sulfur (S) in stimulation of photosynthesis is known. However, information on the involvement of ethylene in GA-induced photosynthetic responses and cadmium (Cd) tolerance is lacking. This work shows that ethylene is involved in S-assimilation, photosynthetic responses and alleviation of Cd stress by GA in mustard (Brassica juncea L.). Plants grown with 200 mg Cd kg(-1) soil were less responsive to ethylene despite high ethylene evolution and showed photosynthetic inhibition. Plants receiving 10 μM GA spraying plus 100 mg S kg(-1) soil supplementation exhibited increased S-assimilation and photosynthetic responses under Cd stress. Application of GA plus S decreased oxidative stress of plants grown with Cd and limited stress ethylene formation to the range suitable for promoting sulfur use efficiency (SUE), glutathione (GSH) production and photosynthesis. The role of ethylene in GA-induced S-assimilation and reversal of photosynthetic inhibition by Cd was substantiated by inhibiting ethylene biosynthesis with the use of aminoethoxyvinylglycine (AVG). The suppression of S-assimilation and photosynthetic responses by inhibiting ethylene in GA plus S treated plants under Cd stress indicated the involvement of ethylene in GA-induced S-assimilation and Cd stress alleviation. The outcome of the study is important to unravel the interaction between GA and ethylene and their role in Cd tolerance in plants. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Adrenaline-induced colonic K+ secretion is mediated by KCa1.1 (BK) channels

DEFF Research Database (Denmark)

Sørensen, Mads Vaarby; Sausbier, Matthias; Ruth, Peter

2010-01-01

. However, the secretory K(+) channel responsible for cAMP-induced K(+) secretion remains to be defined. In this study we used the Ussing chamber to identify adrenaline-induced electrogenic K(+) secretion. We found that the adrenaline-induced electrogenic ion secretion is a compound effect dominated...... variants in colonic enterocytes (STREX and ZERO). Importantly, the ZERO variant known to be activated by cAMP is differentially up-regulated in enterocytes from animals on a high K(+) diet. In summary, these results strongly suggest that the adrenaline-induced distal colonic K(+) secretion is mediated...

Akt-dependent NF-κB activation is required for bile acids to rescue colon cancer cells from stress-induced apoptosis

International Nuclear Information System (INIS)

Shant, Jasleen; Cheng, Kunrong; Marasa, Bernard S.; Wang Jianying; Raufman, Jean-Pierre

2009-01-01

Conjugated secondary bile acids promote human colon cancer cell proliferation by activating EGF receptors (EGFR). We hypothesized that bile acid-induced EGFR activation also mediates cell survival by downstream Akt-regulated activation of NF-κB. Deoxycholyltaurine (DCT) treatment attenuated TNF-α-induced colon cancer cell apoptosis, and stimulated rapid and sustained NF-κB nuclear translocation and transcriptional activity (detected by NF-κB binding to an oligonucleotide consensus sequence and by activation of luciferase reporter gene constructs). Both DCT-induced NF-κB nuclear translocation and attenuation of TNF-α-stimulated apoptosis were dependent on EGFR activation. Inhibitors of nuclear translocation, proteosome activity, and IκBα kinase attenuated NF-κB transcriptional activity. Cell transfection with adenoviral vectors encoding a non-degradable IκBα 'super-repressor' blocked the actions of DCT on both NF-κB activation and TNF-α-induced apoptosis. Likewise, transfection with mutant akt and treatment with a chemical inhibitor of Akt attenuated effects of DCT on NF-κB transcriptional activity and TNF-α-induced apoptosis. Chemical inhibitors of Akt and NF-κB activation also attenuated DCT-induced rescue of H508 cells from ultraviolet radiation-induced apoptosis. Collectively, these observations indicate that, downstream of EGFR, bile acid-induced colon cancer cell survival is mediated by Akt-dependent NF-κB activation. These findings provide a mechanism whereby bile acids increase resistance of colon cancer to chemotherapy and radiation

Ursolic acid mediates photosensitization by initiating mitochondrial-dependent apoptosis

Science.gov (United States)

Lee, Yuan-Hao; Wang, Exing; Kumar, Neeru; Glickman, Randolph D.

2013-02-01

The signaling pathways PI3K/Akt and MAPK play key roles in transcription, translation and carcinogenesis, and may be activated by light exposure. These pathways may be modulated or inhibited by naturally-occurring compounds, such as the triterpenoid, ursolic acid (UA). Previously, the transcription factors p53 and NF-kB, which transactivate mitochondrial apoptosis-related genes, were shown to be differentially modulated by UA. Our current work indicates that UA causes these effects via the mTOR and insulin-mediated pathways. UA-modulated apoptosis, following exposure to UV radiation, is observed to correspond to differential levels of oxidative stress in retinal pigment epithelial (RPE) and skin melanoma (SM) cells. Flow cytometry analysis, DHE (dihydroethidium) staining and membrane permeability assay showed that UA pretreatment potentiated cell cycle arrest and radiation-induced apoptosis selectively on SM cells while DNA photo-oxidative damage (i.e. strand breakage) was reduced, presumably by some antioxidant activity of UA in RPE cells. The UA-mediated NF-κB activation in SM cells was reduced by rapamycin pretreatment, which indicates that these agents exert inter-antagonistic effects in the PI3K/Akt/mTOR pathway. In contrast, the antagonistic effect of UA on the PI3K/Akt pathway was reversed by insulin leading to greater NF-κB and p53 activation in RPE cells. MitoTracker, a mitochondrial functional assay, indicated that mitochondria in RPE cells experienced reduced oxidative stress while those in SM cells exhibited increased oxidative stress upon UA pretreatment. When rapamycin administration was followed by UA, mitochondrial oxidative stress was increased in RPE cells but decreased in SM cells. These results indicate that UA modulates p53 and NF-κB, initiating a mitogenic response to radiation that triggers mitochondria-dependent apoptosis.

Ursolic Acid-Regulated Energy Metabolism—Reliever or Propeller of Ultraviolet-Induced Oxidative Stress and DNA Damage?

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Yuan-Hao Lee

2014-08-01

Full Text Available Ultraviolet (UV light is a leading cause of diseases, such as skin cancers and cataracts. A main process mediating UV-induced pathogenesis is the production of reactive oxygen species (ROS. Excessive ROS levels induce the formation of DNA adducts (e.g., pyrimidine dimers and result in stalled DNA replication forks. In addition, ROS promotes phosphorylation of tyrosine kinase-coupled hormone receptors and alters downstream energy metabolism. With respect to the risk of UV-induced photocarcinogenesis and photodamage, the antitumoral and antioxidant functions of natural compounds become important for reducing UV-induced adverse effects. One important question in the field is what determines the differential sensitivity of various types of cells to UV light and how exogenous molecules, such as phytochemicals, protect normal cells from UV-inflicted damage while potentiating tumor cell death, presumably via interaction with intracellular target molecules and signaling pathways. Several endogenous molecules have emerged as possible players mediating UV-triggered DNA damage responses. Specifically, UV activates the PIKK (phosphatidylinositol 3-kinase-related kinase family members, which include DNA-PKcs, ATM (ataxia telangiectasia mutated and mTOR (mammalian target of rapamycin, whose signaling can be affected by energy metabolism; however, it remains unclear to what extent the activation of hormone receptors regulates PIKKs and whether this crosstalk occurs in all types of cells in response to UV. This review focuses on proteomic descriptions of the relationships between cellular photosensitivity and the phenotypic expression of the insulin/insulin-like growth receptor. It covers the cAMP-dependent pathways, which have recently been shown to regulate the DNA repair machinery through interactions with the PIKK family members. Finally, this review provides a strategic illustration of how UV-induced mitogenic activity is modulated by the insulin

Lysophosphatidic acid signaling through its receptor initiates profibrotic epithelial cell fibroblast communication mediated by epithelial cell derived connective tissue growth factor.

Science.gov (United States)

Sakai, Norihiko; Chun, Jerold; Duffield, Jeremy S; Lagares, David; Wada, Takashi; Luster, Andrew D; Tager, Andrew M

2017-03-01

The expansion of the fibroblast pool is a critical step in organ fibrosis, but the mechanisms driving expansion remain to be fully clarified. We previously showed that lysophosphatidic acid (LPA) signaling through its receptor LPA 1 expressed on fibroblasts directly induces the recruitment of these cells. Here we tested whether LPA-LPA 1 signaling drives fibroblast proliferation and activation during the development of renal fibrosis. LPA 1 -deficient (LPA 1 -/- ) or -sufficient (LPA 1 +/+ ) mice were crossed to mice with green fluorescent protein expression (GFP) driven by the type I procollagen promoter (Col-GFP) to identify fibroblasts. Unilateral ureteral obstruction-induced increases in renal collagen were significantly, though not completely, attenuated in LPA 1 -/- Col-GFP mice, as were the accumulations of both fibroblasts and myofibroblasts. Connective tissue growth factor was detected mainly in tubular epithelial cells, and its levels were suppressed in LPA 1 -/- Col-GFP mice. LPA-LPA 1 signaling directly induced connective tissue growth factor expression in primary proximal tubular epithelial cells, through a myocardin-related transcription factor-serum response factor pathway. Proximal tubular epithelial cell-derived connective tissue growth factor mediated renal fibroblast proliferation and myofibroblast differentiation. Administration of an inhibitor of myocardin-related transcription factor/serum response factor suppressed obstruction-induced renal fibrosis. Thus, targeting LPA-LPA 1 signaling and/or myocardin-related transcription factor/serum response factor-induced transcription could be promising therapeutic strategies for renal fibrosis. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

Proteomic Analysis of Responsive Proteins Induced in Japanese Birch Plantlet Treated with Salicylic Acid

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Hiromu Suzuki

2014-07-01

Full Text Available The present study was performed to unravel the mechanisms of systemic acquired resistance (SAR establishment and resistance signaling pathways against the canker-rot fungus (Inonotus obliquus strain IO-U1 infection in Japanese birch plantlet No.8. Modulation of protein-profile induced by salicylic acid (SA-administration was analyzed, and SA-responsive proteins were identified. In total, 5 specifically expressed, 3 significantly increased, and 3 significantly decreased protein spots were identified using liquid chromatography/tandem mass spectrometry (LC/MS/MS and the sequence tag method. These proteins were malate dehydrogenase, succinate dehydrogenase, phosphoglycerate kinase, diaminopimalate decarboxylase, arginase, chorismate mutase, cyclophilin, aminopeptidase, and unknown function proteins. These proteins are considered to be involved in SAR-establishment mechanisms in the Japanese birch plantlet No 8.

Obeticholic acid protects mice against lipopolysaccharide-induced liver injury and inflammation.

Science.gov (United States)

Xiong, Xi; Ren, Yuqian; Cui, Yun; Li, Rui; Wang, Chunxia; Zhang, Yucai

2017-12-01

Cholestasis, as a main manifestation, induces liver injury during sepsis. The farnesoid X receptor (FXR) plays an important role in regulating bile acid homeostasis. Whether FXR activation by its agonist obeticholic acid (OCA) is contributed to improve sepsis-induced liver injury remains unknown. The aim of the present study was to investigate the effect of OCA on lipopolysaccharide (LPS)-induced acute liver injury in mice. 8-week old male C57BL/6J mice were randomly divided into control group, LPS group, oral OCA group and LPS plus oral OCA (LPS + OCA) group. The serum and livers were collected for further analysis. Serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bile acid (TBA) and total bilirubin (TBIL) were measured at indicated time after LPS administration. Liver sections were stained with hematoxylin & eosin (H&E). Orally OCA pretreatment stimulated the expression of FXR and BSEP in livers and protected mice from LPS-induced hepatocyte apoptosis and inflammatory infiltration. Consistently, LPS-induced higher serum levels of ALT, AST, TBA and TBIL were significantly reversed by OCA administration. Meanwhile, the mRNA levels of interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α) and IL-6 were decreased in livers of mice in LPS + OCA group compared with LPS group. Further investigation indicated that the higher expression of ATF4 and LC3II/I were associated with the protective effect of OCA on LPS-induced liver injury. Orally OCA pretreatment protects mice from LPS-induced liver injury possibly contributed by improved bile acid homeostasis, decreased inflammatory factors and ATF4-mediated autophagy activity in hepatocytes. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

A test of genotypic variation in specificity of herbivore-induced responses in Solidago altissima L. (Asteraceae)

NARCIS (Netherlands)

Uesugi, A.; Poelman, E.H.; Kessler, A.

2013-01-01

Plant-induced responses to multiple herbivores can mediate ecological interactions among herbivore species, thereby influencing herbivore community composition in nature. Several studies have indicated high specificity of induced responses to different herbivore species. In addition, there may be

Swimming Motility Mediates the Formation of Neutrophil Extracellular Traps Induced by Flagellated Pseudomonas aeruginosa.

Directory of Open Access Journals (Sweden)

Madison Floyd

2016-11-01

Full Text Available Pseudomonas aeruginosa is an opportunistic pathogen causing severe infections often characterized by robust neutrophilic infiltration. Neutrophils provide the first line of defense against P. aeruginosa. Aside from their defense conferred by phagocytic activity, neutrophils also release neutrophil extracellular traps (NETs to immobilize bacteria. Although NET formation is an important antimicrobial process, the details of its mechanism are largely unknown. The identity of the main components of P. aeruginosa responsible for triggering NET formation is unclear. In this study, our focus was to identify the main bacterial factors mediating NET formation and to gain insight into the underlying mechanism. We found that P. aeruginosa in its exponential growth phase promoted strong NET formation in human neutrophils while its NET-inducing ability dramatically decreased at later stages of bacterial growth. We identified the flagellum as the primary component of P. aeruginosa responsible for inducing NET extrusion as flagellum-deficient bacteria remained seriously impaired in triggering NET formation. Purified P. aeruginosa flagellin, the monomeric component of the flagellum, does not stimulate NET formation in human neutrophils. P. aeruginosa-induced NET formation is independent of the flagellum-sensing receptors TLR5 and NLRC4 in both human and mouse neutrophils. Interestingly, we found that flagellar motility, not flagellum binding to neutrophils per se, mediates NET release induced by flagellated bacteria. Immotile, flagellar motor-deficient bacterial strains producing paralyzed flagella did not induce NET formation. Forced contact between immotile P. aeruginosa and neutrophils restored their NET-inducing ability. Both the motAB and motCD genetic loci encoding flagellar motor genes contribute to maximal NET release; however the motCD genes play a more important role. Phagocytosis of P. aeruginosa and superoxide production by neutrophils were also

Key mediators of intracellular amino acids signaling to mTORC1 activation.

Science.gov (United States)

Duan, Yehui; Li, Fengna; Tan, Kunrong; Liu, Hongnan; Li, Yinghui; Liu, Yingying; Kong, Xiangfeng; Tang, Yulong; Wu, Guoyao; Yin, Yulong

2015-05-01

Mammalian target of rapamycin complex 1 (mTORC1) is activated by amino acids to promote cell growth via protein synthesis. Specifically, Ras-related guanosine triphosphatases (Rag GTPases) are activated by amino acids, and then translocate mTORC1 to the surface of late endosomes and lysosomes. Ras homolog enriched in brain (Rheb) resides on this surface and directly activates mTORC1. Apart from the presence of intracellular amino acids, Rag GTPases and Rheb, other mediators involved in intracellular amino acid signaling to mTORC1 activation include human vacuolar sorting protein-34 (hVps34) and mitogen-activating protein kinase kinase kinase kinase-3 (MAP4K3). Those molecular links between mTORC1 and its mediators form a complicate signaling network that controls cellular growth, proliferation, and metabolism. Moreover, it is speculated that amino acid signaling to mTORC1 may start from the lysosomal lumen. In this review, we discussed the function of these mediators in mTORC1 pathway and how these mediators are regulated by amino acids in details.

Characterization of Imidazopyridine Compounds as Negative Allosteric Modulators of Proton-Sensing GPR4 in Extracellular Acidification-Induced Responses.

Directory of Open Access Journals (Sweden)

Ayaka Tobo

Full Text Available G protein-coupled receptor 4 (GPR4, previously proposed as the receptor for sphingosylphosphorylcholine, has recently been identified as the proton-sensing G protein-coupled receptor (GPCR coupling to multiple intracellular signaling pathways, including the Gs protein/cAMP and G13 protein/Rho. In the present study, we characterized some imidazopyridine compounds as GPR4 modulators that modify GPR4 receptor function. In the cells that express proton-sensing GPCRs, including GPR4, OGR1, TDAG8, and G2A, extracellular acidification stimulates serum responsive element (SRE-driven transcriptional activity, which has been shown to reflect Rho activity, with different proton sensitivities. Imidazopyridine compounds inhibited the moderately acidic pH-induced SRE activity only in GPR4-expressing cells. Acidic pH-stimulated cAMP accumulation, mRNA expression of inflammatory genes, and GPR4 internalization within GPR4-expressing cells were all inhibited by the GPR4 modulator. We further compared the inhibition property of the imidazopyridine compound with psychosine, which has been shown to selectively inhibit actions induced by proton-sensing GPCRs, including GPR4. In the GPR4 mutant, in which certain histidine residues were mutated to phenylalanine, proton sensitivity was significantly shifted to the right, and psychosine failed to further inhibit acidic pH-induced SRE activation. On the other hand, the imidazopyridine compound almost completely inhibited acidic pH-induced action in mutant GPR4. We conclude that some imidazopyridine compounds show specificity to GPR4 as negative allosteric modulators with a different action mode from psychosine, an antagonist susceptible to histidine residues, and are useful for characterizing GPR4-mediated acidic pH-induced biological actions.

Characterization of Imidazopyridine Compounds as Negative Allosteric Modulators of Proton-Sensing GPR4 in Extracellular Acidification-Induced Responses.

Science.gov (United States)

Tobo, Ayaka; Tobo, Masayuki; Nakakura, Takashi; Ebara, Masashi; Tomura, Hideaki; Mogi, Chihiro; Im, Dong-Soon; Murata, Naoya; Kuwabara, Atsushi; Ito, Saki; Fukuda, Hayato; Arisawa, Mitsuhiro; Shuto, Satoshi; Nakaya, Michio; Kurose, Hitoshi; Sato, Koichi; Okajima, Fumikazu

2015-01-01

G protein-coupled receptor 4 (GPR4), previously proposed as the receptor for sphingosylphosphorylcholine, has recently been identified as the proton-sensing G protein-coupled receptor (GPCR) coupling to multiple intracellular signaling pathways, including the Gs protein/cAMP and G13 protein/Rho. In the present study, we characterized some imidazopyridine compounds as GPR4 modulators that modify GPR4 receptor function. In the cells that express proton-sensing GPCRs, including GPR4, OGR1, TDAG8, and G2A, extracellular acidification stimulates serum responsive element (SRE)-driven transcriptional activity, which has been shown to reflect Rho activity, with different proton sensitivities. Imidazopyridine compounds inhibited the moderately acidic pH-induced SRE activity only in GPR4-expressing cells. Acidic pH-stimulated cAMP accumulation, mRNA expression of inflammatory genes, and GPR4 internalization within GPR4-expressing cells were all inhibited by the GPR4 modulator. We further compared the inhibition property of the imidazopyridine compound with psychosine, which has been shown to selectively inhibit actions induced by proton-sensing GPCRs, including GPR4. In the GPR4 mutant, in which certain histidine residues were mutated to phenylalanine, proton sensitivity was significantly shifted to the right, and psychosine failed to further inhibit acidic pH-induced SRE activation. On the other hand, the imidazopyridine compound almost completely inhibited acidic pH-induced action in mutant GPR4. We conclude that some imidazopyridine compounds show specificity to GPR4 as negative allosteric modulators with a different action mode from psychosine, an antagonist susceptible to histidine residues, and are useful for characterizing GPR4-mediated acidic pH-induced biological actions.

Electroacupuncture preconditioning-induced neuroprotection may be mediated by glutamate transporter type 2

OpenAIRE

Zhu, Xiaoling; Yin, Jinbo; Li, Liaoliao; Ma, Lei; Tan, Hongying; Deng, Jiao; Chen, Shaoyang; Zuo, Zhiyi

2013-01-01

Electroacupuncture has been shown to induce a preconditioning effect in the brain. The mechanisms for this protection are not fully elucidated. We hypothesize that this protection is mediated by excitatory amino acid transporters (EAATs) that have been shown to be neuroprotective. To test this hypothesis, two-month old male Sprague-Dawley rats and EAAT type 3 (EAAT3) knockout mice received or did not receive 30-min electroacupuncture once a day for 5 consecutive days. They were subjected to a...

Magnetic Resonance Imaging of Therapy-Induced Necrosis Using Gadolinium-Chelated Polyglutamic Acids

International Nuclear Information System (INIS)

Jackson, Edward F.; Esparza-Coss, Emilio; Wen Xiaoxia; Ng, Chaan S.; Daniel, Sherita L.; Price, Roger E.; Rivera, Belinda; Charnsangavej, Chusilp; Gelovani, Juri G.; Li Chun

2007-01-01

Purpose: Necrosis is the most common morphologic alteration found in tumors and surrounding normal tissues after radiation therapy or chemotherapy. Accurate measurement of necrosis may provide an early indication of treatment efficacy or associated toxicity. The purpose of this report is to evaluate the selective accumulation of polymeric paramagnetic magnetic resonance (MR) contrast agents-gadolinium p-aminobenzyl-diethylenetriaminepentaacetic acid-poly(glutamic acid) (L-PG-DTPA-Gd and D-PG-DTPA-Gd)-in necrotic tissue. Methods and Materials: Two different solid tumor models, human Colo-205 xenograft and syngeneic murine OCA-1 ovarian tumors, were used in this study. Necrotic response was induced by treatment with poly(L-glutamic acid)-paclitaxel conjugate (PG-TXL). T 1 -weighted spin-echo images were obtained immediately and up to 4 days after contrast injection and compared with corresponding histologic specimens. Two low-molecular-weight contrast agents, DTPA-Gd and oligomeric(L-glutamic acid)-DTPA-Gd, were used as nonspecific controls. Results: Initially, there was minimal tumor enhancement after injection of either L-PG-DTPA-Gd or D-PG-DTPA-Gd, but rapid enhancement after injection of low-molecular-weight agents. However, polymeric contrast agents, but not low-molecular-weight contrast agents, caused sustained enhancement in regions of tumor necrosis in both tumors treated with PG-TXL and untreated tumors. These data indicate that high molecular weight, rather than in vivo biodegradation, is necessary for the specific localization of polymeric MR contrast agents to necrotic tissue. Moreover, biotinylated L-PG-DTPA-Gd colocalized with macrophages in the tumor necrotic areas, suggesting that selective accumulation of L- and D-PG-DTPA-Gd in necrotic tissue was mediated through residing macrophages. Conclusions: Our data suggest that MR imaging with PG-DTPA-Gd may be a useful technique for noninvasive characterization of treatment-induced necrosis

Evidence that shock-induced immune suppression is mediated by adrenal hormones and peripheral beta-adrenergic receptors.

Science.gov (United States)

Cunnick, J E; Lysle, D T; Kucinski, B J; Rabin, B S

1990-07-01

Our previous work has demonstrated that presentations of mild foot-shock to Lewis rats induces a suppression of splenic and peripheral blood lymphocyte responses to nonspecific T-cell mitogens. The present study demonstrated that adrenalectomy prevented the shock-induced suppression of the mitogenic response of peripheral blood T-cells but did not attenuate the suppression of splenic T-cells. Conversely, the beta-adrenergic receptor antagonists, propranolol and nadolol, attenuated the shock-induced suppression of splenic T-cells in a dose-dependent manner but did not attenuate suppression of the blood mitogen response. These data indicate that distinct mechanisms mediate the shock-induced suppression of T-cell responsiveness to mitogens in the spleen and the peripheral blood. The results indicate that the peripheral release of catecholamines is responsible for splenic immune suppression and that adrenal hormones, which do not interact with beta-adrenergic receptors, are responsible for shock-induced suppression of blood mitogenic responses.

Aminocaproic Acid and Tranexamic Acid Fail to Reverse Dabigatran-Induced Coagulopathy.

Science.gov (United States)

Levine, Michael; Huang, Margaret; Henderson, Sean O; Carmelli, Guy; Thomas, Stephen H

In recent years, dabigatran has emerged as a popular alternative to warfarin for treatment of atrial fibrillation. If rapid reversal is required, however, no reversal agent has clearly been established. The primary purpose of this manuscript was to evaluate the efficacy of tranexamic acid and aminocaproic acid as agents to reverse dabigatran-induced coagulopathy. Rats were randomly assigned to 6 groups. Each rat received either dabigatran or oral placebo, followed by saline, tranexamic acid, or aminocaproic acid. An activated clotting test was used to measure the coagulopathy. Neither tranexamic acid nor aminocaproic acid successfully reversed dabigatran-induced coagulopathy. In this rodent model of dabigatran-induced coagulopathy, neither tranexamic acid nor aminocaproic acid were able to reverse the coagulopathy.

Salvianolic acid B protects against paraquat-induced pulmonary injury by mediating Nrf2/Nox4 redox balance and TGF-β1/Smad3 signaling

Energy Technology Data Exchange (ETDEWEB)

Liu, Bin, E-mail: iamicehe@163.com [Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Logistic University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Cao, Bo, E-mail: caobo19814@126.com [Logistics University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Tianjin Key Laboratory of Cardiovascular Remodeling and Target Organ Injury, Tianjin, 300162 (China); Zhang, Di, E-mail: zhangdibad@163.com [Department of Otorhinolaryngology Head and Neck Surgery, Institute of Otorhinolaryngology, Tianjin First Center Hospital, Tianjin 300192 (China); Xiao, Na [Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Logistic University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Chen, Hong [Logistics University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Li, Guo-qiang; Peng, Shou-chun [Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Logistic University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Wei, Lu-qing, E-mail: luqing-wei@163.com [Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Logistic University of Chinese People' s Armed Police Force, Tianjin 300162 (China)

2016-10-15

The present study was aimed at exploring the protective effects of Salvianolic acid B (SalB) against paraquat (PQ)-induced lung injury in mice. Lung fibrotic injuries were induced in mice by a single intragastrical administration of 300 mg/kg PQ, then the mice were administrated with 200 mg/kg, 400 mg/kg SalB, 100 mg/kg vitamin C (Vit C) and dexamethasone (DXM) for 14 days. PQ-triggered structure distortion, collagen overproduction, excessive inflammatory infiltration, pro-inflammatory cytokine release, and oxidative stress damages in lung tissues and mortality of mice were attenuated by SalB in a dose-dependent manner. Furthermore, SalB was noted to enhance the expression and nuclear translocation of nuclear factor erythroid 2–related factor 2 (Nrf2) and reduce expression of the reactive oxygen species-generating enzyme Nox4 [NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) oxidase-4]. SalB also inhibited the increasing expression of transforming growth factor (TGF)-β1 and the phosphorylation of its downstream target Smad3 which were enhanced by PQ. These results suggest that SalB may exert protective effects against PQ-induced lung injury and pulmonary fibrosis. Its mechanisms involve the mediation of Nrf2/Nox4 redox balance and TGF-β1/Smad3 signaling. - Highlights: • Salvianolic acid B (SalB) reduced Paraquat-induced mortality and pulmonary injury in mice. • SalB has anti-oxidation, anti-inflammatory and anti-fibrogenic effects simultaneously. • Its mechanisms were targeting Nrf2-Nox4 redox balance and TGF-β1/Smad3 signaling.

Salvianolic acid B protects against paraquat-induced pulmonary injury by mediating Nrf2/Nox4 redox balance and TGF-β1/Smad3 signaling

International Nuclear Information System (INIS)

Liu, Bin; Cao, Bo; Zhang, Di; Xiao, Na; Chen, Hong; Li, Guo-qiang; Peng, Shou-chun; Wei, Lu-qing

2016-01-01

The present study was aimed at exploring the protective effects of Salvianolic acid B (SalB) against paraquat (PQ)-induced lung injury in mice. Lung fibrotic injuries were induced in mice by a single intragastrical administration of 300 mg/kg PQ, then the mice were administrated with 200 mg/kg, 400 mg/kg SalB, 100 mg/kg vitamin C (Vit C) and dexamethasone (DXM) for 14 days. PQ-triggered structure distortion, collagen overproduction, excessive inflammatory infiltration, pro-inflammatory cytokine release, and oxidative stress damages in lung tissues and mortality of mice were attenuated by SalB in a dose-dependent manner. Furthermore, SalB was noted to enhance the expression and nuclear translocation of nuclear factor erythroid 2–related factor 2 (Nrf2) and reduce expression of the reactive oxygen species-generating enzyme Nox4 [NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) oxidase-4]. SalB also inhibited the increasing expression of transforming growth factor (TGF)-β1 and the phosphorylation of its downstream target Smad3 which were enhanced by PQ. These results suggest that SalB may exert protective effects against PQ-induced lung injury and pulmonary fibrosis. Its mechanisms involve the mediation of Nrf2/Nox4 redox balance and TGF-β1/Smad3 signaling. - Highlights: • Salvianolic acid B (SalB) reduced Paraquat-induced mortality and pulmonary injury in mice. • SalB has anti-oxidation, anti-inflammatory and anti-fibrogenic effects simultaneously. • Its mechanisms were targeting Nrf2-Nox4 redox balance and TGF-β1/Smad3 signaling.

Activation of AMPK by berberine induces hepatic lipid accumulation by upregulation of fatty acid translocase CD36 in mice

International Nuclear Information System (INIS)

Choi, You-Jin; Lee, Kang-Yo; Jung, Seung-Hwan; Kim, Hyung Sik; Shim, Gayong; Kim, Mi-Gyeong; Oh, Yu-Kyoung; Oh, Seon-Hee; Jun, Dae Won; Lee, Byung-Hoon

2017-01-01

Emerging evidence has shown that berberine has a protective effect against metabolic syndrome such as obesity and type II diabetes mellitus by activating AMP-activated protein kinase (AMPK). AMPK induces CD36 trafficking to the sarcolemma for fatty acid uptake and oxidation in contracting muscle. However, little is known about the effects of AMPK on CD36 regulation in the liver. We investigated whether AMPK activation by berberine affects CD36 expression and fatty acid uptake in hepatocytes and whether it is linked to hepatic lipid accumulation. Activation of AMPK by berberine or transduction with adenoviral vectors encoding constitutively active AMPK in HepG2 and mouse primary hepatocytes increased the expression and membrane translocation of CD36, resulting in enhanced fatty acid uptake and lipid accumulation as determined by BODIPY-C16 and Nile red fluorescence, respectively. Activation of AMPK by berberine induced the phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2) and subsequently induced CCAAT/enhancer-binding protein β (C/EBPβ) binding to the C/EBP-response element in the CD36 promoter in hepatocytes. In addition, hepatic CD36 expression and triglyceride levels were increased in normal diet-fed mice treated with berberine, but completely prevented when hepatic CD36 was silenced with adenovirus containing CD36-specific shRNA. Taken together, prolonged activation of AMPK by berberine increased CD36 expression in hepatocytes, resulting in fatty acid uptake via processes linked to hepatocellular lipid accumulation and fatty liver. - Highlights: • Berberine increases the expression and membrane translocation of CD36 in hepatocytes. • The increase of CD36 results in enhanced fatty acid uptake and lipid accumulation. • Berberine-induced fatty liver is mediated by AMPK-ERK-C/EBPβ pathway. • CD36-specific shRNA inhibited berberine-induced lipid accumulation in liver.

Activation of AMPK by berberine induces hepatic lipid accumulation by upregulation of fatty acid translocase CD36 in mice

Energy Technology Data Exchange (ETDEWEB)

Choi, You-Jin; Lee, Kang-Yo; Jung, Seung-Hwan [College of Pharmacy, Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742 (Korea, Republic of); Kim, Hyung Sik [School of Pharmacy, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Shim, Gayong; Kim, Mi-Gyeong; Oh, Yu-Kyoung [College of Pharmacy, Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742 (Korea, Republic of); Oh, Seon-Hee [The Division of Natural Medical Sciences, College of Health Science, Chosun University, Gwangju 501-759 (Korea, Republic of); Jun, Dae Won [Internal Medicine, Hanyang University School of Medicine, Seoul 133-791 (Korea, Republic of); Lee, Byung-Hoon, E-mail: lee@snu.ac.kr [College of Pharmacy, Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742 (Korea, Republic of)

2017-02-01

Emerging evidence has shown that berberine has a protective effect against metabolic syndrome such as obesity and type II diabetes mellitus by activating AMP-activated protein kinase (AMPK). AMPK induces CD36 trafficking to the sarcolemma for fatty acid uptake and oxidation in contracting muscle. However, little is known about the effects of AMPK on CD36 regulation in the liver. We investigated whether AMPK activation by berberine affects CD36 expression and fatty acid uptake in hepatocytes and whether it is linked to hepatic lipid accumulation. Activation of AMPK by berberine or transduction with adenoviral vectors encoding constitutively active AMPK in HepG2 and mouse primary hepatocytes increased the expression and membrane translocation of CD36, resulting in enhanced fatty acid uptake and lipid accumulation as determined by BODIPY-C16 and Nile red fluorescence, respectively. Activation of AMPK by berberine induced the phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2) and subsequently induced CCAAT/enhancer-binding protein β (C/EBPβ) binding to the C/EBP-response element in the CD36 promoter in hepatocytes. In addition, hepatic CD36 expression and triglyceride levels were increased in normal diet-fed mice treated with berberine, but completely prevented when hepatic CD36 was silenced with adenovirus containing CD36-specific shRNA. Taken together, prolonged activation of AMPK by berberine increased CD36 expression in hepatocytes, resulting in fatty acid uptake via processes linked to hepatocellular lipid accumulation and fatty liver. - Highlights: • Berberine increases the expression and membrane translocation of CD36 in hepatocytes. • The increase of CD36 results in enhanced fatty acid uptake and lipid accumulation. • Berberine-induced fatty liver is mediated by AMPK-ERK-C/EBPβ pathway. • CD36-specific shRNA inhibited berberine-induced lipid accumulation in liver.

Tumour–stromal interactions in acid-mediated invasion: A mathematical model

KAUST Repository

Martin, Natasha K.; Gaffney, Eamonn A.; Gatenby, Robert A.; Maini, Philip K.

2010-01-01

constraint. In particular, the production of acid by tumour cells and the subsequent creation of a low extracellular pH environment has been explored in several 'acid-mediated tumour invasion' models where the acidic environment facilitates normal cell death

Streptococcus pneumoniae and Pseudomonas aeruginosa pneumonia induce distinct host responses.

Science.gov (United States)

McConnell, Kevin W; McDunn, Jonathan E; Clark, Andrew T; Dunne, W Michael; Dixon, David J; Turnbull, Isaiah R; Dipasco, Peter J; Osberghaus, William F; Sherman, Benjamin; Martin, James R; Walter, Michael J; Cobb, J Perren; Buchman, Timothy G; Hotchkiss, Richard S; Coopersmith, Craig M

2010-01-01

Pathogens that cause pneumonia may be treated in a targeted fashion by antibiotics, but if this therapy fails, then treatment involves only nonspecific supportive measures, independent of the inciting infection. The purpose of this study was to determine whether host response is similar after disparate infections with similar mortalities. Prospective, randomized controlled study. Animal laboratory in a university medical center. Pneumonia was induced in FVB/N mice by either Streptococcus pneumoniae or two different concentrations of Pseudomonas aeruginosa. Plasma and bronchoalveolar lavage fluid from septic animals was assayed by a microarray immunoassay measuring 18 inflammatory mediators at multiple time points. The host response was dependent on the causative organism as well as kinetics of mortality, but the pro-inflammatory and anti-inflammatory responses were independent of inoculum concentration or degree of bacteremia. Pneumonia caused by different concentrations of the same bacteria, Pseudomonas aeruginosa, also yielded distinct inflammatory responses; however, inflammatory mediator expression did not directly track the severity of infection. For all infections, the host response was compartmentalized, with markedly different concentrations of inflammatory mediators in the systemic circulation and the lungs. Hierarchical clustering analysis resulted in the identification of five distinct clusters of the host response to bacterial infection. Principal components analysis correlated pulmonary macrophage inflammatory peptide-2 and interleukin-10 with progression of infection, whereas elevated plasma tumor necrosis factor sr2 and macrophage chemotactic peptide-1 were indicative of fulminant disease with >90% mortality within 48 hrs. Septic mice have distinct local and systemic responses to Streptococcus pneumoniae and Pseudomonas aeruginosa pneumonia. Targeting specific host inflammatory responses induced by distinct bacterial infections could represent a

Arabidopsis cysteine-rich receptor-like kinase 45 functions in the responses to abscisic acid and abiotic stresses

KAUST Repository

Zhang, Xiujuan; Yang, Guanyu; Shi, Rui; Han, Xiaomin; Qi, Liwang; Wang, Ruigang; Xiong, Liming; Li, Guojing

2013-01-01

The phytohormone abscisic acid (ABA) regulates seed germination, plant growth and development, and response to abiotic stresses such as drought and salt stresses. Receptor-like kinases are well known signaling components that mediate plant responses

Integrating nitric oxide into salicylic acid and jasmonic acid/ethylene plant defense pathways

DEFF Research Database (Denmark)

Mur, Luis A J; Prats, Elena; Pierre, Sandra

2013-01-01

to be tailored to particular biotic stresses. Nitric oxide (NO) has emerged as a major signal influencing resistance mediated by both signalling pathways but no attempt has been made to integrate NO into established SA/JA/ET interactions. NO has been shown to act as an inducer or suppressor of signalling along......Plant defence against pests and pathogens is known to be conferred by either salicylic acid (SA) or jasmonic acid (JA)/ethylene (ET) pathways, depending on infection or herbivore-grazing strategy. It is well attested that SA and JA/ET pathways are mutually antagonistic allowing defence responses...

Quinone-induced protein handling changes: Implications for major protein handling systems in quinone-mediated toxicity

International Nuclear Information System (INIS)

Xiong, Rui; Siegel, David; Ross, David

2014-01-01

Para-quinones such as 1,4-Benzoquinone (BQ) and menadione (MD) and ortho-quinones including the oxidation products of catecholamines, are derived from xenobiotics as well as endogenous molecules. The effects of quinones on major protein handling systems in cells; the 20/26S proteasome, the ER stress response, autophagy, chaperone proteins and aggresome formation, have not been investigated in a systematic manner. Both BQ and aminochrome (AC) inhibited proteasomal activity and activated the ER stress response and autophagy in rat dopaminergic N27 cells. AC also induced aggresome formation while MD had little effect on any protein handling systems in N27 cells. The effect of NQO1 on quinone induced protein handling changes and toxicity was examined using N27 cells stably transfected with NQO1 to generate an isogenic NQO1-overexpressing line. NQO1 protected against BQ–induced apoptosis but led to a potentiation of AC- and MD-induced apoptosis. Modulation of quinone-induced apoptosis in N27 and NQO1-overexpressing cells correlated only with changes in the ER stress response and not with changes in other protein handling systems. These data suggested that NQO1 modulated the ER stress response to potentiate toxicity of AC and MD, but protected against BQ toxicity. We further demonstrated that NQO1 mediated reduction to unstable hydroquinones and subsequent redox cycling was important for the activation of the ER stress response and toxicity for both AC and MD. In summary, our data demonstrate that quinone-specific changes in protein handling are evident in N27 cells and the induction of the ER stress response is associated with quinone-mediated toxicity. - Highlights: • Unstable hydroquinones contributed to quinone-induced ER stress and toxicity

Quinone-induced protein handling changes: Implications for major protein handling systems in quinone-mediated toxicity

Energy Technology Data Exchange (ETDEWEB)

Xiong, Rui; Siegel, David; Ross, David, E-mail: david.ross@ucdenver.edu

2014-10-15

Para-quinones such as 1,4-Benzoquinone (BQ) and menadione (MD) and ortho-quinones including the oxidation products of catecholamines, are derived from xenobiotics as well as endogenous molecules. The effects of quinones on major protein handling systems in cells; the 20/26S proteasome, the ER stress response, autophagy, chaperone proteins and aggresome formation, have not been investigated in a systematic manner. Both BQ and aminochrome (AC) inhibited proteasomal activity and activated the ER stress response and autophagy in rat dopaminergic N27 cells. AC also induced aggresome formation while MD had little effect on any protein handling systems in N27 cells. The effect of NQO1 on quinone induced protein handling changes and toxicity was examined using N27 cells stably transfected with NQO1 to generate an isogenic NQO1-overexpressing line. NQO1 protected against BQ–induced apoptosis but led to a potentiation of AC- and MD-induced apoptosis. Modulation of quinone-induced apoptosis in N27 and NQO1-overexpressing cells correlated only with changes in the ER stress response and not with changes in other protein handling systems. These data suggested that NQO1 modulated the ER stress response to potentiate toxicity of AC and MD, but protected against BQ toxicity. We further demonstrated that NQO1 mediated reduction to unstable hydroquinones and subsequent redox cycling was important for the activation of the ER stress response and toxicity for both AC and MD. In summary, our data demonstrate that quinone-specific changes in protein handling are evident in N27 cells and the induction of the ER stress response is associated with quinone-mediated toxicity. - Highlights: • Unstable hydroquinones contributed to quinone-induced ER stress and toxicity.

Glycyrrhizic acid alleviates bleomycin-induced pulmonary fibrosis in rats

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Lili eGao

2015-10-01

Full Text Available Idiopathic pulmonary fibrosis is a progressive and lethal form of interstitial lung disease that lacks effective therapies at present. Glycyrrhizic acid (GA, a natural compound extracted from a traditional Chinese herbal medicine Glycyrrhiza glabra, was recently reported to benefit lung injury and liver fibrosis in animal models, yet whether GA has a therapeutic effect on pulmonary fibrosis is unknown. In this study, we investigated the potential therapeutic effect of GA on pulmonary fibrosis in a rat model with bleomycin (BLM-induced pulmonary fibrosis. The results indicated that GA treatment remarkably ameliorated BLM-induced pulmonary fibrosis and attenuated BLM-induced inflammation, oxidative stress, epithelial-mesenchymal transition and activation of tansforming growth factor-beta signaling pathway in the lungs. Further, we demonstrated that GA treatment inhibited proliferation of 3T6 fibroblast cells, induced cell cycle arrest and promoted apoptosis in vitro, implying that GA-mediated suppression of fibroproliferation may contribute to the anti-fibrotic effect against BLM-induced pulmonary fibrosis. In summary, our study suggests a therapeutic potential of GA in the treatment of pulmonary fibrosis.

Acid-deposition research program. Volume 2. Effects of acid-forming emissions on soil microorganisms and microbially-mediated processes

Energy Technology Data Exchange (ETDEWEB)

Visser, S.; Danielson, R.M.; Parr, J.F.

1987-02-01

The interactions of soil physical, chemical, and biological processes are ultimately expressed in a soil's fertility and its capacity for plant production. Consequently, much of the research conducted to date regarding the impact of acid-forming pollutants on soil properties has been geared towards possible effects on plant productivity. This trend continues in this paper where the effects of acidic deposition on microbial communities are reviewed in relation to potential impact on plant growth. The objectives of the review are to discuss: (1) The effects of acid-forming emissions (primarily S-containing pollutants) on microbial community structure with emphasis on qualitative and quantitative aspects; (2) The effects of acidic deposition on microbially mediated processes (i.e., community functions); (3) Acidification effects of pollutants on symbiotic and disease-causing microorganisms. The symbionts discussed include ectomycorrhizal fungi, vesicular-arbuscular mycorrhizal fungi, and N/sub 2/-fixing bacteria, particularly Rhizobium, while the disease-causing microorganisms will include those responsible for foliage, stem, and root diseases.

Transient Receptor Potential Vanilloid 1 Expression Mediates Capsaicin-Induced Cell Death

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Ricardo Ramírez-Barrantes

2018-06-01

Full Text Available The transient receptor potential (TRP ion channel family consists of a broad variety of non-selective cation channels that integrate environmental physicochemical signals for dynamic homeostatic control. Involved in a variety of cellular physiological processes, TRP channels are fundamental to the control of the cell life cycle. TRP channels from the vanilloid (TRPV family have been directly implicated in cell death. TRPV1 is activated by pain-inducing stimuli, including inflammatory endovanilloids and pungent exovanilloids, such as capsaicin (CAP. TRPV1 activation by high doses of CAP (>10 μM leads to necrosis, but also exhibits apoptotic characteristics. However, CAP dose–response studies are lacking in order to determine whether CAP-induced cell death occurs preferentially via necrosis or apoptosis. In addition, it is not known whether cytosolic Ca2+ and mitochondrial dysfunction participates in CAP-induced TRPV1-mediated cell death. By using TRPV1-transfected HeLa cells, we investigated the underlying mechanisms involved in CAP-induced TRPV1-mediated cell death, the dependence of CAP dose, and the participation of mitochondrial dysfunction and cytosolic Ca2+ increase. Together, our results contribute to elucidate the pathophysiological steps that follow after TRPV1 stimulation with CAP. Low concentrations of CAP (1 μM induce cell death by a mechanism involving a TRPV1-mediated rapid and transient intracellular Ca2+ increase that stimulates plasma membrane depolarization, thereby compromising plasma membrane integrity and ultimately leading to cell death. Meanwhile, higher doses of CAP induce cell death via a TRPV1-independent mechanism, involving a slow and persistent intracellular Ca2+ increase that induces mitochondrial dysfunction, plasma membrane depolarization, plasma membrane loss of integrity, and ultimately, cell death.

TolC is important for bacterial survival and oxidative stress response in Salmonella enterica serovar Choleraesuis in an acidic environment.

Science.gov (United States)

Lee, Jen-Jie; Wu, Ying-Chen; Kuo, Chih-Jung; Hsuan, Shih-Ling; Chen, Ter-Hsin

2016-09-25

The outer membrane protein TolC, which is one of the key components of several multidrug efflux pumps, is thought to be involved in various independent systems in Enterobacteriaceae. Since the acidic environment of the stomach is an important protection barrier against foodborne pathogen infections in hosts, we evaluated whether TolC played a role in the acid tolerance of Salmonella enterica serovar Choleraesuis. Comparison of the acid tolerance of the tolC mutant and the parental wild-type strain showed that the absence of TolC limits the ability of Salmonella to sustain life under extreme acidic conditions. Additionally, the mutant exhibited morphological changes during growth in an acidic medium, leading to the conflicting results of cell viability measured by spectrophotometry and colony-forming unit counting. Reverse-transcriptional-PCR analysis indicated that acid-related molecules, apparatus, or enzymes and oxidation-induced factors were significantly affected by the acidic environment in the null-tolC mutant. The elongated cellular morphology was restored by adding antioxidants to the culture medium. Furthermore, we found that increased cellular antioxidative activity provides an overlapping protection against acid killing, demonstrating the complexity of the bacterial acid stress response. Our findings reinforce the multifunctional characteristics of TolC in acid tolerance or oxidative stress resistance and support the correlative protection mechanism between oxygen- and acid-mediated stress responses in Salmonella enterica serovar Choleraesuis. Copyright © 2016 Elsevier B.V. All rights reserved.

Muscarinic receptors mediate cold stress-induced detrusor overactivity in type 2 diabetes mellitus rats.

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Imamura, Tetsuya; Ishizuka, Osamu; Ogawa, Teruyuki; Yamagishi, Takahiro; Yokoyama, Hitoshi; Minagawa, Tomonori; Nakazawa, Masaki; Gautam, Sudha Silwal; Nishizawa, Osamu

2014-10-01

This study determined if muscarinic receptors could mediate the cold stress-induced detrusor overactivity induced in type 2 diabetes mellitus rats. Ten-week-old female Goto-Kakizaki diabetic rats (n = 12) and Wister Kyoto non-diabetic rats (n = 12) were maintained on a high-fat diet for 4 weeks. Cystometric investigations of the unanesthetized rats were carried out at room temperature (27 ± 2°C) for 20 min. They were intravenously administered imidafenacin (0.3 mg/kg, n = 6) or vehicle (n = 6). After 5 min, the rats were transferred to a low temperature (4 ± 2°C) for 40 min where the cystometry was continued. The rats were then returned to room temperature for the final cystometric measurements. Afterwards, expressions of bladder muscarinic receptor M3 and M2 messenger ribonucleic acids and proteins were assessed by reverse transcription polymerase chain reaction and immunohistochemistry. In non-diabetic Wister Kyoto rats, imidafenacin did not reduce cold stress-induced detrusor overactivity. In diabetic Goto-Kakizaki rats, just after transfer to a low temperature, the cold stress-induced detrusor overactivity in imidafenacin-treated rats was reduced compared with vehicle-treated rats. Within the urinary bladders, the ratio of M3 to M2 receptor messenger ribonucleic acid in the diabetic Goto-Kakizaki rats was significantly higher than that of the non-diabetic Wister Kyoto rats. The proportion of muscarinic M3 receptor-positive area within the detrusor in diabetic Goto-Kakizaki rats was also significantly higher than that in non-diabetic Wister Kyoto rats. Imidafenacin partially inhibits cold stress-induced detrusor overactivity in diabetic Goto-Kakizaki rats. In this animal model, muscarinic M3 receptors partially mediate cold stress-induced detrusor overactivity. © 2014 The Japanese Urological Association.

Effects of Ursodeoxycholic Acid and Insulin on Palmitate-Induced ROS Production and Down-Regulation of PI3K/Akt Signaling Activity.

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Yokoyama, Kunihiro; Tatsumi, Yasuaki; Hayashi, Kazuhiko; Goto, Hidemi; Ishikawa, Tetsuya; Wakusawa, Shinya

2017-01-01

In obese and diabetic patients, plasma free fatty acid (FFA) levels are often elevated and may play a causal role in insulin resistance and reactive oxygen species (ROS) production. We have previously shown that ursodeoxycholic acid (UDCA) has antioxidative activity through the phosphatidylinositol 3-kinase (PI3K)/Akt signaling-mediated glutathione production. In this study, we investigated the effects of UDCA on insulin response by analyzing intracellular ROS and the activation of the PI3K/Akt signaling pathway in HepG2 cells treated with palmitate. The level of ROS was quantified using 2',7'-dichlorodihydrofluorescein diacetate (H 2 DCFDA), and the activation of the PI3K/Akt signaling pathway was determined by Western blotting assay using appropriate antibodies. The intracellular ROS levels were increased by palmitate but were reduced by treatment with UDCA and insulin. Furthermore, insulin significantly stimulated the phosphorylation of Akt. When the cells were pre-treated with palmitate, insulin-induced Akt-phosphorylation was markedly inhibited. However, when the cells were treated with palmitate and UDCA, the effects of insulin were partially restored. UDCA may have protective effects against palmitate-induced decreases in responsiveness to insulin.

Cadmium induced radioadaptive response via an ATM-independent H2S/cystathionine γ-lyase modulation

International Nuclear Information System (INIS)

Pan Yan; Yuan Dexiao; Zhang Jianghong; Shao Chunlin

2011-01-01

The combined exposure to environmental toxicants such as heavy metals and radiation is an important research area in health protection. Here we explored cadmium induced radioadaptive response (RAR) and investigated the role of hydrogen sulfide (H 2 S) and ATM kinase in this response. Our data showed that the cadmium ions with a sub-lethal concentration could induce RAR in Chang liver cells towards subsequent γ-irradiation and this response could be abrogated by DL-propargylglycine (PPG), the endogenous H 2 S synthetase inhibitor of cystathionine γ-lyase (CSE), but not by aminooxyacetic acid (AOAA), the inhibitor of cystathionine β-synthase (CBS). Moreover, the pretreatment of cells with NaHS also stimulated cellular adaptive response to radiation. Both cadmium treatment and irradiation up-regulated the expression of CSE protein in a time-dependent manner but had no influence on the expression of CBS protein. In the primed cells, the time course of CBS expression showed no significant difference with the cells treated with 2Gy irradiation alone, however, the CSE expression was easier to reach the maximum level, indicating a more efficient H 2 S production by CSE. Moreover, the cadmium-induced RAR was totally suppressed by KU-55933, a specific ATM inhibitor that did not change the CSE expression after radiation. However, exogenous H 2 S decreased the phosphorylation level of radiation-induced ATM. In conclusion, the present results demonstrate firstly that H 2 S is involved in the cadmium induced cross-adaptive response to challenging radiation. CSE, rather than CBS, may mainly responsible for the H 2 S production during this RAR which may also be mediated by ATM pathway. However, the activation of CSE is independent of ATM but could negatively regulate the phosphorylation of ATM.

Essential fatty acids and lipid mediators. Endocannabinoids

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G. Caramia

2012-03-01

Full Text Available In 1929 Burr and Burr discovered the essential fatty acids omega-6 and omega-3. Since then, researchers have shown a growing interest in polyunsaturated fatty acids (PUFA as precursors of “lipid mediator” molecules, often with opposing effects, prostaglandins, prostacyclins, thromboxanes, leukotrienes, lipossines, resolvines, protectines, maresins that regulate immunity, platelet aggregation, inflammation, etc. They showed that the balance between omega-3 and omega-6 acids has a profound influence on all the body’s inflammatory responses and a raised level of PUFA omega-3 in tissue correlate with a reduced incidence of degenerative cardiovascular disease, some mental illnesses such as depression, and neuro-degenerative diseases such as Alzheimer’s. The CYP-catalyzed epoxidation and hydroxylation of arachidonic acid (AA were established recently as the so-called third branch of AGE cascade. Cytochrome P450 (CYP epoxygenases convert AA to four epoxyeicosatrienoic acid (EET regioisomers, that produce vascular relaxation anti-inflammatory effects on blood vessels and in the kidney, promote angiogenesis, and protect ischemic myocardium and brain. Eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA are accessible to CYP enzymes in the same way as AA. Metabolites derived from EPA include epoxyeicosatetraenoic acids (EETR and hydroxyeicosapentaenoic acids (19- and 20-HEPE, whereas DHA include epoxydocosapentaenoic acids (EDPs hydroxydocosahexaenoic acids (21- and 22-HDoHE. For many of the CYP isoforms, the n-3 PUFAs are the preferred substrates and the available data suggest that some of the vasculo- and cardioprotective effects attributed to dietary n-3 PUFAs may be mediated by CYP-dependent metabolites of EPA and DHA. From AA derives also endocannabinoids like anandamide (N-arachidonoylethanolamine and 2-arachidonoylglycerol, capable of mimicking the pharmacological actions of the active principle of Cannabis sativa preparations such as

Transcriptomic profiling of linolenic acid-responsive genes in ROS signalling from RNA-seq data in Arabidopsis

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Capilla eMata-Pérez

2015-03-01

Full Text Available Linolenic acid (Ln released from chloroplast membrane galactolipids is a precursor of the phytohormone jasmonic acid (JA. The involvement of this hormone in different plant biological processes, such as responses to biotic stress conditions, has been extensively studied. However, the role of Ln in the regulation of gene expression during abiotic stress situations mediated by cellular redox changes and/or by oxidative stress processes remains poorly understood. An RNA-seq approach has increased our knowledge of the interplay among Ln, oxidative stress and ROS signalling that mediates abiotic stress conditions. Transcriptome analysis with the aid of RNA-seq in the absence of oxidative stress revealed that the incubation of Arabidopsis thaliana cell suspension cultures (ACSC with Ln resulted in the modulation of 7525 genes, of which 3034 genes had a 2 fold-change, being 533 up- and 2501 down-regulated genes, respectively. Thus, RNA-seq data analysis showed that an important set of these genes were associated with the jasmonic acid biosynthetic pathway including lypoxygenases (LOXs and Allene oxide cyclases (AOCs. In addition, several transcription factor families involved in the response to biotic stress conditions (pathogen attacks or herbivore feeding, such as WRKY, JAZ, MYC and LRR were also modified in response to Ln. However, this study also shows that Ln has the capacity to modulate the expression of genes involved in the response to abiotic stress conditions, particularly those mediated by ROS signalling. In this regard, we were able to identify new targets such as galactinol synthase 1 (GOLS1, methionine sulfoxide reductase (MSR and alkenal reductase in ACSC. It is therefore possible to suggest that, in the absence of any oxidative stress, Ln is capable of modulating new sets of genes involved in the signalling mechanism mediated by additional abiotic stresses (salinity, UV and high light intensity and especially in stresses mediated by ROS.

Synthesis of lipid mediators during UVB-induced inflammatory hyperalgesia in rats and mice.

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Marco Sisignano

Full Text Available Peripheral sensitization during inflammatory pain is mediated by a variety of endogenous proalgesic mediators including a number of oxidized lipids, some of which serve endogenous modulators of sensory TRP-channels. These lipids are eicosanoids of the arachidonic acid and linoleic acid pathway, as well as lysophophatidic acids (LPAs. However, their regulation pattern during inflammatory pain and their contribution to peripheral sensitization is still unclear. Here, we used the UVB-model for inflammatory pain to investigate alterations of lipid concentrations at the site of inflammation, the dorsal root ganglia (DRGs as well as the spinal dorsal horn and quantified 21 lipid species from five different lipid families at the peak of inflammation 48 hours post irradiation. We found that known proinflammatory lipids as well as lipids with unknown roles in inflammatory pain to be strongly increased in the skin, whereas surprisingly little changes of lipid levels were seen in DRGs or the dorsal horn. Importantly, although there are profound differences between the number of cytochrome (CYP genes between mice and rats, CYP-derived lipids were regulated similarly in both species. Since TRPV1 agonists such as LPA 18∶1, 9- and 13-HODE, 5- and 12-HETE were elevated in the skin, they may contribute to thermal hyperalgesia and mechanical allodynia during UVB-induced inflammatory pain. These results may explain why some studies show relatively weak analgesic effects of cyclooxygenase inhibitors in UVB-induced skin inflammation, as they do not inhibit synthesis of other proalgesic lipids such as LPA 18∶1, 9-and 13-HODE and HETEs.

Increased gamma-aminobutyric acid levels in mouse brain induce loss of righting reflex, but not immobility, in response to noxious stimulation.

Science.gov (United States)

Katayama, Sohtaro; Irifune, Masahiro; Kikuchi, Nobuhito; Takarada, Tohru; Shimizu, Yoshitaka; Endo, Chie; Takata, Takashi; Dohi, Toshihiro; Sato, Tomoaki; Kawahara, Michio

2007-06-01

The general anesthetic state comprises behavioral and perceptual components, including amnesia, unconsciousness, and immobility. gamma-Aminobutyric acidergic (GABAergic) inhibitory neurotransmission is an important target for anesthetic action at the in vitro cellular level. In vivo, however, the functional relevance of enhancing GABAergic neurotransmission in mediating essential components of the general anesthetic state is unknown. Gabaculine is a GABA-transaminase inhibitor that inhibits degradation of released GABA, and consequently increases endogenous GABA in the central nervous system. Here, we examined, behaviorally, the ability of increased GABA levels to produce components of the general anesthetic state. All drugs were administered systemically in adult male ddY mice. To assess the general anesthetic components, two end-points were used. One was loss of righting reflex (LORR; as a measure of unconsciousness); the other was loss of movement in response to tail-clamp stimulation (as a measure of immobility). Gabaculine induced LORR in a dose-dependent fashion with a 50% effective dose of 100 (75-134; 95% confidence limits) mg/kg. The behavioral and microdialysis studies revealed that the endogenous GABA-induced LORR occurred in a brain concentration-dependent manner. However, even larger doses of gabaculine (285-400 mg/kg) produced no loss of tail-clamp response. In contrast, all the tested volatile anesthetics concentration-dependently abolished both righting and tail-clamp response, supporting the evidence that volatile anesthetics act on a variety of molecular targets. These findings indicate that LORR is associated with enhanced GABAergic neurotransmission, but that immobility in response to noxious stimulation is not, suggesting that LORR and immobility are mediated through different neuronal pathways and/or regions in the central nervous system.

Involvement of WRKY Transcription Factors in Abscisic-Acid-Induced Cold Tolerance of Banana Fruit.

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Luo, Dong-Lan; Ba, Liang-Jie; Shan, Wei; Kuang, Jian-Fei; Lu, Wang-Jin; Chen, Jian-Ye

2017-05-10

Phytohormone abscisic acid (ABA) and plant-specific WRKY transcription factors (TFs) have been implicated to play important roles in various stress responses. The involvement of WRKY TFs in ABA-mediated cold tolerance of economical fruits, such as banana fruit, however remains largely unknown. Here, we reported that ABA application could induce expressions of ABA biosynthesis-related genes MaNCED1 and MaNCED2, increase endogenous ABA contents, and thereby enhance cold tolerance in banana fruit. Four banana fruit WRKY TFs, designated as MaWRKY31, MaWRKY33, MaWRKY60, and MaWRKY71, were identified and characterized. All four of these MaWRKYs were nuclear-localized and displayed transactivation activities. Their expressions were induced by ABA treatment during cold storage. More importantly, the gel mobility shift assay and transient expression analysis revealed that MaWRKY31, MaWRKY33, MaWRKY60, and MaWRKY71 directly bound to the W-box elements in MaNCED1 and MaNCED2 promoters and activated their expressions. Taken together, our findings demonstrate that banana fruit WRKY TFs are involved in ABA-induced cold tolerance by, at least in part, increasing ABA levels via directly activating NECD expressions.

Combination therapies in adjuvant with topical ALA-mediated photodynamic therapy for DMBA-induced hamster buccal pouch premalignant lesions

Science.gov (United States)

Yang, Deng-Fu; Hsu, Yih-Chih

2012-03-01

In Taiwan, oral cancer has becomes the fastest growth male cancer disease due to the betel nut chewing habit combing with smoking and alcohol-drinking lifestyle of people. In order to eliminate the systemic phototoxic effect of 5-aminolevulinic acid (ALA), this study was designed to use a topical ALA-mediated PDT for treatment of DMBA-induced hamster buccal pouch precancerous lesions. DMBA was applied to one of the buccal pouches of hamsters thrice a week for 10 to 12 weeks. Cancerous lesions were induced and proven by histological examination. These DMBA-induced cancerous lesions were used for testing the efficacy of topical ALA-mediated PDT. Before PDT, fluorescence spectroscopy was used to determine when ALA reached its peak level in the lesional epithelial cells after topical application of ALA gel. We found that ALA reached its peak level in precancerous lesions about 2.5 hrs after topical application of ALA gel. The cancerous lesions in hamsters were then treated with topical ALA -mediated PDT with light exposure dose of 150 J/cm2 using LED 635 nm fiber-guided light device. Visual examination demonstrated that adjuvant topical ALA -mediated PDT group has shown better therapeutic results in compared to those of non-adjuvant topical ALA-mediated PDT group for DMBA-induced hamster buccal pouch precancerous lesions.

Inducible nitric-oxide synthase plays a minimal role in lymphocytic choriomeningitis virus-induced, T cell-mediated protective immunity and immunopathology

DEFF Research Database (Denmark)

Bartholdy, C; Nansen, A; Christensen, Jeanette Erbo

1999-01-01

-mediated immune response was found to be unaltered in iNOS-deficient mice compared with wild-type C57BL/6 mice, and LCMV- induced general immunosuppression was equally pronounced in both strains. In vivo analysis revealed identical kinetics of virus clearance, as well as unaltered clinical severity of systemic......By using mice with a targetted disruption in the gene encoding inducible nitric-oxide synthase (iNOS), we have studied the role of nitric oxide (NO) in lymphocytic choriomeningitis virus (LCMV)-induced, T cell-mediated protective immunity and immunopathology. The afferent phase of the T cell...... LCMV infection in both strains. Concerning the outcome of intracerebral infection, no significant differences were found between iNOS-deficient and wild-type mice in the number or composition of mononuclear cells found in the cerebrospinal fluid on day 6 post-infection. Likewise, NO did not influence...

Agonists for G-protein-coupled receptor 84 (GPR84) alter cellular morphology and motility but do not induce pro-inflammatory responses in microglia.

Science.gov (United States)

Wei, Li; Tokizane, Kyohei; Konishi, Hiroyuki; Yu, Hua-Rong; Kiyama, Hiroshi

2017-10-03

Several G-protein-coupled receptors (GPCRs) have been shown to be important signaling mediators between neurons and glia. In our previous screening for identification of nerve injury-associated GPCRs, G-protein-coupled receptor 84 (GPR84) mRNA showed the highest up-regulation by microglia after nerve injury. GPR84 is a pro-inflammatory receptor of macrophages in a neuropathic pain mouse model, yet its function in resident microglia in the central nervous system is poorly understood. We used endogenous, natural, and surrogate agonists for GPR84 (capric acid, embelin, and 6-OAU, respectively) and examined their effect on mouse primary cultured microglia in vitro. 6-n-Octylaminouracil (6-OAU), embelin, and capric acid rapidly induced membrane ruffling and motility in cultured microglia obtained from C57BL/6 mice, although these agonists failed to promote microglial pro-inflammatory cytokine expression. Concomitantly, 6-OAU suppressed forskolin-induced increase of cAMP in cultured microglia. Pertussis toxin, an inhibitor of Gi-coupled signaling, completely suppressed 6-OAU-induced microglial membrane ruffling and motility. In contrast, no 6-OAU-induced microglial membrane ruffling and motility was observed in microglia from DBA/2 mice, a mouse strain that does not express functional GPR84 protein due to endogenous nonsense mutation of the GPR84 gene. GPR84 mediated signaling causes microglial motility and membrane ruffling but does not promote pro-inflammatory responses. As GPR84 is a known receptor for medium-chain fatty acids, those released from damaged brain cells may be involved in the enhancement of microglial motility through GPR84 after neuronal injury.

Ferulic acid with ascorbic acid synergistically extenuates the mitochondrial dysfunction during beta-adrenergic catecholamine induced cardiotoxicity in rats.

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Yogeeta, Surinder Kumar; Raghavendran, Hanumantha Rao Balaji; Gnanapragasam, Arunachalam; Subhashini, Rajakannu; Devaki, Thiruvengadam

2006-10-27

Disruption of mitochondria and free radical mediated tissue injury have been reported during cardiotoxicity induced by isoproterenol (ISO), a beta-adrenergic catecholamine. The present study was designed to investigate the effect of the combination of ferulic acid (FA) and ascorbic acid (AA) on the mitochondrial damage in ISO induced cardiotoxicity. Induction of rats with ISO (150 mg/kg b.wt., i.p.) for 2 days resulted in a significant decrease in the activities of respiratory chain enzymes (NADH dehydrogenase and cytochrome c-oxidase), tricarboxylic acid cycle enzymes (isocitrate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, alpha-ketoglutarate dehydrogenase), mitochondrial antioxidants (GPx, GST, SOD, CAT, GSH), cytochromes (b, c, c1, aa3) and in the level of mitochondrial phospholipids. A marked elevation in mitochondrial lipid peroxidation, mitochondrial levels of cholesterol, triglycerides and free fatty acids were also observed in ISO intoxicated rats. Pre-co-treatment with the combination of FA (20 mg/kg b.wt.) and AA (80 mg/kg b.wt.) orally for 6 days significantly enhanced the attenuation of these functional abnormalities and restored normal mitochondrial function when compared to individual drug treated groups. Mitigation of ISO induced biochemical and morphological changes in mitochondria were more pronounced with a combination of FA and AA rather than the individual drug treated groups. Transmission electron microscopic observations also correlated with these biochemical parameters. Hence, these findings demonstrate the synergistic ameliorative potential of FA and AA on mitochondrial function during beta-adrenergic catecholamine induced cardiotoxicity and associated oxidative stress in rats.

UV-C-Induced alleviation of transcriptional gene silencing through plant–plant communication: Key roles of jasmonic acid and salicylic acid pathways

Energy Technology Data Exchange (ETDEWEB)

Xu, Wei; Wang, Ting [Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, P.O. Box 1138, Hefei, Anhui, 230031 (China); Xu, Shaoxin [School of physics and materials science, Anhui University, Hefei, Anhui, 230601 (China); Li, Fanghua; Deng, Chenguang; Wu, Lijun; Wu, Yuejin [Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, P.O. Box 1138, Hefei, Anhui, 230031 (China); Bian, Po, E-mail: bianpo@ipp.ac.cn [Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, P.O. Box 1138, Hefei, Anhui, 230031 (China)

2016-08-15

Highlights: • Transcriptional gene silencing (TGS) in plants can be epigenetically alleviated by volatile signals from UV-C- irradiated neighboring plants. • Alleviation of TGS can be induced by UV-C irradiation through plant–plant–plant communication. • JA and SA signals take part in interplant communication for alleviation of TGS. - Abstract: Plant stress responses at the epigenetic level are expected to allow more permanent changes of gene expression and potentially long-term adaptation. While it has been reported that plants subjected to adverse environments initiate various stress responses in their neighboring plants, little is known regarding epigenetic responses to external stresses mediated by plant–plant communication. In this study, we show that DNA repetitive elements of Arabidopsis thaliana, whose expression is inhibited epigenetically by transcriptional gene silencing (TGS) mechanism, are activated by UV-C irradiation through airborne plant–plant and plant–plant–plant communications, accompanied by DNA demethylation at CHH sites. Moreover, the TGS is alleviated by direct treatments with exogenous methyl jasmonate (MeJA) and methyl salicylate (MeSA). Further, the plant–plant and plant–plant–plant communications are blocked by mutations in the biosynthesis or signaling of jasmonic acid (JA) or salicylic acid (SA), indicating that JA and SA pathways are involved in the interplant communication for epigenetic responses. For the plant–plant–plant communication, stress cues are relayed to the last set of receiver plants by promoting the production of JA and SA signals in relaying plants, which exhibit upregulated expression of genes for JA and SA biosynthesis and enhanced emanation of MeJA and MeSA.

UV-C-Induced alleviation of transcriptional gene silencing through plant–plant communication: Key roles of jasmonic acid and salicylic acid pathways

International Nuclear Information System (INIS)

Xu, Wei; Wang, Ting; Xu, Shaoxin; Li, Fanghua; Deng, Chenguang; Wu, Lijun; Wu, Yuejin; Bian, Po

2016-01-01

Highlights: • Transcriptional gene silencing (TGS) in plants can be epigenetically alleviated by volatile signals from UV-C- irradiated neighboring plants. • Alleviation of TGS can be induced by UV-C irradiation through plant–plant–plant communication. • JA and SA signals take part in interplant communication for alleviation of TGS. - Abstract: Plant stress responses at the epigenetic level are expected to allow more permanent changes of gene expression and potentially long-term adaptation. While it has been reported that plants subjected to adverse environments initiate various stress responses in their neighboring plants, little is known regarding epigenetic responses to external stresses mediated by plant–plant communication. In this study, we show that DNA repetitive elements of Arabidopsis thaliana, whose expression is inhibited epigenetically by transcriptional gene silencing (TGS) mechanism, are activated by UV-C irradiation through airborne plant–plant and plant–plant–plant communications, accompanied by DNA demethylation at CHH sites. Moreover, the TGS is alleviated by direct treatments with exogenous methyl jasmonate (MeJA) and methyl salicylate (MeSA). Further, the plant–plant and plant–plant–plant communications are blocked by mutations in the biosynthesis or signaling of jasmonic acid (JA) or salicylic acid (SA), indicating that JA and SA pathways are involved in the interplant communication for epigenetic responses. For the plant–plant–plant communication, stress cues are relayed to the last set of receiver plants by promoting the production of JA and SA signals in relaying plants, which exhibit upregulated expression of genes for JA and SA biosynthesis and enhanced emanation of MeJA and MeSA.

Exosome-mediated microRNA transfer plays a role in radiation-induced bystander effect.

Science.gov (United States)

Xu, Shuai; Wang, Jufang; Ding, Nan; Hu, Wentao; Zhang, Xurui; Wang, Bing; Hua, Junrui; Wei, Wenjun; Zhu, Qiyun

2015-01-01

Bystander effects can be induced through cellular communication between irradiated cells and non-irradiated cells. The signals that mediate this cellular communication, such as cytokines, reactive oxygen species, nitric oxide and even microRNAs, can be transferred between cells via gap junctions or extracellular medium. We have previously reported that miR-21, a well described DDR (DNA damage response) microRNA, is involved in radiation-induced bystander effects through a medium-mediated way. However, the mechanisms of the microRNA transfer have not been elucidated in details. In the present study, it was found that exosomes isolated from irradiated conditioned medium could induce bystander effects. Furthermore, we demonstrated plenty of evidences that miR-21, which is up-regulated as a result of mimic transfection or irradiation, can be transferred from donor or irradiated cells into extracellular medium and subsequently get access to the recipient or bystander cells through exosomes to induce bystander effects. Inhibiting the miR-21 expression in advance can offset the bystander effects to some extent. From all of these results, it can be concluded that the exosome-mediated microRNA transfer plays an important role in the radiation-induced bystander effects. These findings provide new insights into the functions of microRNAs and the cellular communication between the directly irradiated cells and the non-irradiated cells.

Substrate-induced ubiquitylation and endocytosis of yeast amino acid permeases.

Science.gov (United States)

Ghaddar, Kassem; Merhi, Ahmad; Saliba, Elie; Krammer, Eva-Maria; Prévost, Martine; André, Bruno

2014-12-01

Many plasma membrane transporters are downregulated by ubiquitylation, endocytosis, and delivery to the lysosome in response to various stimuli. We report here that two amino acid transporters of Saccharomyces cerevisiae, the general amino acid permease (Gap1) and the arginine-specific permease (Can1), undergo ubiquitin-dependent downregulation in response to their substrates and that this downregulation is not due to intracellular accumulation of the transported amino acids but to transport catalysis itself. Following an approach based on permease structural modeling, mutagenesis, and kinetic parameter analysis, we obtained evidence that substrate-induced endocytosis requires transition of the permease to a conformational state preceding substrate release into the cell. Furthermore, this transient conformation must be stable enough, and thus sufficiently populated, for the permease to undergo efficient downregulation. Additional observations, including the constitutive downregulation of two active Gap1 mutants altered in cytosolic regions, support the model that the substrate-induced conformational transition inducing endocytosis involves remodeling of cytosolic regions of the permeases, thereby promoting their recognition by arrestin-like adaptors of the Rsp5 ubiquitin ligase. Similar mechanisms might control many other plasma membrane transporters according to the external concentrations of their substrates. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Increased Incretin But Not Insulin Response after Oral versus Intravenous Branched Chain Amino Acids.

Science.gov (United States)

Gojda, Jan; Straková, Radka; Plíhalová, Andrea; Tůma, Petr; Potočková, Jana; Polák, Jan; Anděl, Michal

2017-01-01

Branched chain amino acids (BCAAs) are known to exert an insulinotropic effect. Whether this effect is mediated by incretins (glucagon like peptide 1 [GLP-1] or glucose-dependent insulinotropic peptide [GIP]) is not known. The aim of this study was to show whether an equivalent dose of BCAA elicits a greater insulin and incretin response when administered orally than intravenously (IV). Eighteen healthy, male subjects participated in 3 tests: IV application of BCAA solution, oral ingestion of BCAA and placebo in an equivalent dose (30.7 ± 1.1 g). Glucose, insulin, C-peptide, glucagon, GLP-1, GIP, valine, leucine and isoleucine concentrations were measured. Rise in serum BCAA was achieved in both BCAA tests, with incremental areas under the curve (iAUC) being 2.1 times greater for IV BCAA compared with those of the oral BCAA test (p BCAA induced comparable insulin response greater than placebo (240 min insulin iAUC: oral 3,411 ± 577 vs. IV 2,361 ± 384 vs. placebo 961.2 ± 175 pmol/L, p = 0.0006). Oral BCAA induced higher GLP-1 (p BCAA tests with no change in the placebo group. An equivalent dose of BCAA elicited a comparable insulin and greater incretin response when administered orally and not when administered through IV. We conclude that insulinotropic effects of BCAA are partially incretin dependent. © 2017 S. Karger AG, Basel.

Plasmodium falciparum-Derived Uric Acid Precipitates Induce Maturation of Dendritic Cells

Science.gov (United States)

van de Hoef, Diana L.; Coppens, Isabelle; Holowka, Thomas; Ben Mamoun, Choukri; Branch, OraLee; Rodriguez, Ana

2013-01-01

Malaria is characterized by cyclical fevers and high levels of inflammation, and while an early inflammatory response contributes to parasite clearance, excessive and persistent inflammation can lead to severe forms of the disease. Here, we show that Plasmodium falciparum-infected erythrocytes contain uric acid precipitates in the cytoplasm of the parasitophorous vacuole, which are released when erythrocytes rupture. Uric acid precipitates are highly inflammatory molecules that are considered a danger signal for innate immunity and are the causative agent in gout. We determined that P. falciparum-derived uric acid precipitates induce maturation of human dendritic cells, increasing the expression of cell surface co-stimulatory molecules such as CD80 and CD86, while decreasing human leukocyte antigen-DR expression. In accordance with this, uric acid accounts for a significant proportion of the total stimulatory activity induced by parasite-infected erythrocytes. Moreover, the identification of uric acid precipitates in P. falciparum- and P. vivax-infected erythrocytes obtained directly from malaria patients underscores the in vivo and clinical relevance of our findings. Altogether, our data implicate uric acid precipitates as a potentially important contributor to the innate immune response to Plasmodium infection and may provide a novel target for adjunct therapies. PMID:23405174

Arabidopsis MAP kinase 4 regulates salicylic acid- and jasmonic acid/ethylene-dependent responses via EDS1 and PAD4

DEFF Research Database (Denmark)

Brodersen, P; Petersen, M; Nielsen, Henrik Bjørn

2006-01-01

Arabidopsis MPK4 has been implicated in plant defense regulation because mpk4 knockout plants exhibit constitutive activation of salicylic acid (SA)-dependent defenses, but fail to induce jasmonic acid (JA) defense marker genes in response to JA. We show here that mpk4 mutants are also defective...

Lysergic acid diethylamide causes photoreceptor cell damage through inducing inflammatory response and oxidative stress.

Science.gov (United States)

Hu, Qi-Di; Xu, Ling-Li; Gong, Yan; Wu, Guo-Hai; Wang, Yu-Wen; Wu, Shan-Jun; Zhang, Zhe; Mao, Wei; Zhou, Yu-Sheng; Li, Qin-Bo; Yuan, Jian-Shu

2018-01-19

Lysergic acid diethylamide (LSD), a classical hallucinogen, was used as a popular and notorious substance of abuse in various parts of the world. Its abuse could result in long-lasting abnormalities in retina and little is known about the exact mechanism. This study was to investigate the effect of LSD on macrophage activation state at non-toxic concentration and its resultant toxicity to photoreceptor cells. Results showed that cytotoxicity was caused by LSD on 661 W cells after co-culturing with RAW264.7 cells. Treatment with LSD-induced RAW264.7 cells to the M1 phenotype, releasing more pro-inflammatory cytokines, and increasing the M1-related gene expression. Moreover, after co-culturing with RAW264.7 cells, significant oxidative stress in 661 W cells treated with LSD was observed, by increasing the level of malondialdehyde (MDA) and reactive oxygen species (ROS), and decreasing the level of glutathione (GSH) and the activity of superoxide dismutase (SOD). Our study demonstrated that LSD caused photoreceptor cell damage by inducing inflammatory response and resultant oxidative stress, providing the scientific rationale for the toxicity of LSD to retina.