Controlling frustrated magnetism on the kagome lattice by uniaxial-strain tuning

It is predicted that strongly interacting spins on a frustrated lattice may lead to a quantum disordered ground state or even form a quantum spin liquid with exotic low-energy excitations. However, a thorough tuning of the frustration strength, separating its effects from those of disorder and other factors, is pending. Here we break the symmetry of a kagome-lattice compound in a controlled manner by applying $in$ $situ$ uniaxial stress. The transition temperature of $\rm Y_3Cu_9(OH)_{18}OCl_8$ is linearly enhanced with strain, $\Delta T_{\rm N}/T_{\rm N} \approx 10\%$ upon in-plane compression of order $1\%$, providing clear evidence for a release of frustration and its pivotal role for magnetic order. Our comprehensive $^1$H NMR results suggest a $\overrightarrow{Q}=(1/3\times 1/3)$ state under unstrained conditions and further reveal an incomplete antiferromagnetic transition with fluctuating moments in this strongly frustrated system.Comment: 7 pages total, 4 pages main text, 5 figure

Optical properties, electron-phonon coupling, and Raman scattering of vanadium ladder compounds

The electronic structure of two V-based ladder compounds, the quarter-filled NaV$_2$O$_5$ in the symmetric phase and the iso-structural half-filled CaV$_2$O$_5$ is investigated by ab initio calculations. Based on the bandstructure we determine the dielectric tensor $\epsilon(\omega)$ of these systems in a wide energy range. The frequencies and eigenvectors of the fully symmetric A$_{g}$ phonon modes and the corresponding electron-phonon and spin-phonon coupling parameters are also calculated from first-principles. We determine the Raman scattering intensities of the A$_g$ phonon modes as a function of polarization and frequency of the exciting light. All results, i.e. shape and magnitude of the dielectric function, phonon frequencies and Raman intensities show very good agreement with available experimental data.Comment: 11 pages, 10 figure

Modeling of Diffusion and Incorporation of Interstitial Oxygen Ions at the TiN/SiO2 Interface

Silica-based resistive random access memory devices have become an active research area due to complementary metal-oxide-semiconductor compatibility and recent dramatic increases in their performance and endurance. In spite of both experimental and theoretical insights gained into the electroforming process, many atomistic aspects of the set and reset operation of these devices are still poorly understood. Recently a mechanism of electroforming process based on the formation of neutral oxygen vacancies (VO0) and interstitial O ions (Oi2-) facilitated by electron injection into the oxide has been proposed. In this work, we extend the description of the bulk (Oi2-) migration to the interface of amorphous SiO2 with the polycrystaline TiN electrode, using density functional theory simulations. The results demonstrate a strong kinetic and thermodynamic drive for the movement of Oi2- to the interface, with dramatically reduced incorporation energies and migration barriers close to the interface. The arrival of Oi2- at the interface is accompanied by preferential oxidation of undercoordinated Ti sites at the interface, forming a Ti-O layer. We investigate how O ions incorporate into a perfect and defective ∑5(012)[100] grain boundary (GB) in TiN oriented perpendicular to the interface. Our simulations demonstrate the preferential incorporation of Oi at defects within the TiN GB and their fast diffusion along a passivated grain boundary. They explain how, as a result of electroforming, the system undergoes very significant structural changes with the oxide being significantly reduced, interface being oxidized, and part of the oxygen leaving the system

MDR1 causes resistance to the antitumour drug miltefosine

Miltefosine (hexadecylphosphocholine) is used for topical treatment of breast cancers. It has been shown previously that a high percentage of breast carcinomas express MDR1 or MRP. We investigated the sensitivity of MDR1 -expressing cells to treatment with miltefosine. We show that cells overexpressing MDR1 (NCI/ADR-RES, KB-8-5, KB-C1, CCRF/VCR1000, CCRF/ADR5000) were less sensitive to miltefosine treatment when compared to the sensitive parental cell lines. HeLa cells transfected with MDR1 exhibited resistance to the compound, indicating that expression of this gene is sufficient to reduce the sensitivity to miltefosine. The resistance of MDR1 -expressing cells to miltefosine was less pronounced than that to adriamycin or vinblastine. Expression of MDR2 did not correlate with the resistance to miltefosine. As shown by a fluorescence quenching assay using MIANS-labelled P-glycoprotein (PGP), miltefosine bound to PGP with a K d of approximately 7 μM and inhibited PGP-ATPase activity with an IC 50 of approximately 35 μM. Verapamil was not able to reverse the resistance to miltefosine. Concentrations of miltefosine up to approximately 60 μM stimulated, whereas higher concentrations inhibited the transport of [3H]-colchicine with an IC 50 of approximately 297 μM. Binding studies indicated that miltefosine seems to interact with the transmembrane domain and not the cytosolic nucleotide-binding domain of PGP. These data indicate that expression of MDR1 may reduce the response to miltefosine in patients and that this compound interacts with PGP in a manner different from a number of other substrates. © 2001 Cancer Research Campaign www.bjcancer.co

Quantitative phosphoproteomics of cytotoxic T cells to reveal Protein Kinase D 2 regulated networks

The focus of the present study was to characterize the phosphoproteome of cytotoxic T cells and to explore the role of the serine threonine kinase PKD2 (Protein Kinase D2) in the phosphorylation networks of this key lymphocyte population. We used Stable Isotope Labeling of Amino acids in Culture (SILAC) combined with phosphopeptide enrichment and quantitative mass-spectrometry to determine the impact of PKD2 loss on the cytotoxic T cells phosphoproteome. We identified 15,871 phosphorylations on 3505 proteins in cytotoxic T cells. 450 phosphosites on 281 proteins were down-regulated and 300 phosphosites on 196 proteins were up-regulated in PKD2 null cytotoxic T cells. These data give valuable new insights about the protein phosphorylation networks operational in effector T cells and reveal that PKD2 regulates directly and indirectly about 5% of the cytotoxic T-cell phosphoproteome. PKD2 candidate substrates identified in this study include proteins involved in two distinct biological functions: regulation of protein sorting and intracellular vesicle trafficking, and control of chromatin structure, transcription, and translation. In other cell types, PKD substrates include class II histone deacetylases such as HDAC7 and actin regulatory proteins such as Slingshot. The current data show these are not PKD substrates in primary T cells revealing that the functional role of PKD isoforms is different in different cell lineages

Insect chemical ecology: chemically mediated interactions and novel applications in agriculture

Forum PaperInsect chemical ecology (ICE) evolved as a discipline concerned with plant–insect interactions, and also with a strong focus on intraspecific pheromone-mediated communication. Progress in this field has rendered a more complete picture of how insects exploit chemical information in their surroundings in order to survive and navigate their world successfully. Simultaneously, this progress has prompted new research questions about the evolution of insect chemosensation and related ecological adaptations, molecular mechanisms that mediate commonly observed behaviors, and the consequences of chemically mediated interactions in different ecosystems. Themed meetings, workshops, and summer schools are ideal platforms for discussing scientific advancements as well as identifying gaps and challenges within the discipline. From the 11th to the 22nd of June 2018, the 11th annual PhD course in ICE was held at the Swedish University of Agricultural Sciences (SLU) Alnarp, Sweden. The course was made up of 35 student participants from 22 nationalities (Fig. 1a) as well as 32 lecturers. Lectures and laboratory demonstrations were supported by literature seminars, and four broad research areas were covered: (1) multitrophic interactions and plant defenses, (2) chemical communication focusing on odor sensing, processing, and behavior, (3) disease vectors, and (4) applied aspects of basic ICE research in agriculture. This particular article contains a summary and brief synthesis of these main emergent themes and discussions from the ICE 2018 course. In addition, we also provide suggestions on teaching the next generation of ICE scientists, especially during unprecedented global situationsinfo:eu-repo/semantics/publishedVersio

A Dual Receptor Crosstalk Model of G-Protein-Coupled Signal Transduction

Macrophage cells that are stimulated by two different ligands that bind to G-protein-coupled receptors (GPCRs) usually respond as if the stimulus effects are additive, but for a minority of ligand combinations the response is synergistic. The G-protein-coupled receptor system integrates signaling cues from the environment to actuate cell morphology, gene expression, ion homeostasis, and other physiological states. We analyze the effects of the two signaling molecules complement factors 5a (C5a) and uridine diphosphate (UDP) on the intracellular second messenger calcium to elucidate the principles that govern the processing of multiple signals by GPCRs. We have developed a formal hypothesis, in the form of a kinetic model, for the mechanism of action of this GPCR signal transduction system using data obtained from RAW264.7 macrophage cells. Bayesian statistical methods are employed to represent uncertainty in both data and model parameters and formally tie the model to experimental data. When the model is also used as a tool in the design of experiments, it predicts a synergistic region in the calcium peak height dose response that results when cells are simultaneously stimulated by C5a and UDP. An analysis of the model reveals a potential mechanism for crosstalk between the Gαi-coupled C5a receptor and the Gαq-coupled UDP receptor signaling systems that results in synergistic calcium release

Environmentally induced changes in antioxidant phenolic compounds levels in wild plants

[EN] Different adverse environmental conditions cause oxidative stress in plants by generation of reactive oxygen species (ROS). Accordingly, a general response to abiotic stress is the activation of enzymatic and non-enzymatic antioxidant systems. Many phenolic compounds, especially flavonoids, are known antioxidants and efficient ROS scavengers in vitro, but their exact role in plant stress responses in nature is still under debate. The aim of our work is to investigate this role by correlating the degree of environmental stress with phenolic and flavonoid levels in stress-tolerant plants. Total phenolic and antioxidant flavonoid contents were determined in 19 wild species. Meteorological data and plant and soil samples were collected in three successive seasons from four Mediterranean ecosystems: salt marsh, dune, semiarid and gypsum habitats. Changes in phenolic and flavonoid levels were correlated with the environmental conditions of the plants and were found to depend on both the taxonomy and ecology of the investigated species. Despite species-specific differences, principal component analyses of the results established a positive correlation between plant phenolics and several environmental parameters, such as altitude, and those related to water stress: temperature, evapotranspiration, and soil water deficit. The correlation with salt stress was, however, very weak. The joint analysis of all the species showed the lowest phenolic and flavonoid levels in the halophytes from the salt marsh. This finding supports previous data indicating that the halophytes analysed here do not undergo oxidative stress in their natural habitat and therefore do not need to activate antioxidant systems as a defence against salinity.This work has been funded by the Spanish Ministry of Science and Innovation (Project CGL2008-00438/BOS), with contribution from the European Regional Development Fund. Thanks to Dr. Rafael Herrera for critical reading of the manuscript.Bautista, I.; Boscaiu, M.; Lidón, A.; Llinares Palacios, JV.; Lull, C.; Donat-Torres, MP.; Mayoral García-Berlanga, O.... (2016). Environmentally induced changes in antioxidant phenolic compounds levels in wild plants. Acta Physiologiae Plantarum. 38(1):1-15. https://doi.org/10.1007/s11738-015-2025-2S115381Agati G, Biricolti S, Guidi L, Ferrini F, Fini A, Tattini M (2011) The biosynthesis of flavonoids is enhanced similarly by UV radiation and root zone salinity in L. vulgare leaves. J Plant Physiol 168:204–212Agati G, Brunetti C, Di Ferdinando M, Ferrini F, Pollastri S, Tattini M (2013) Functional roles of flavonoids in photoprotection: new evidence, lessons from the past. Plant Physiol Biochem 72:35–45Albert A, Sareedenchai V, Heller W, Seidlitz HK, Zidorn C (2009) Temperature is the key to altitudinal variation of phenolics in Arnica montana L. cv. ARBO. Oecologia 160:1–8Appel K, Hirt H (2004) Reactive oxygen species: metabolism, oxidative stress, and signal transduction. Annu Rev Plant Biol 55:373–399Bachereau F, Marigo G, Asta J (1998) Effect of solar radiation (UV and visible) at high altitude on CAM-cycling and phenolic compounds biosynthesis in Sedum album. Physiol Plant 104:203–210Ballizany WL, Hofmann RV, Jahufer MZZ, Barrett BB (2012) Multivariate associations of flavonoid and biomass accumulation in white clover (Trifolium repens) under drought. Funct Plant Biol 39:167–177Bieza K, Lois R (2001) An Arabidopsis mutant tolerant to lethal ultraviolet-B levels shows constitutively elevated accumulation of flavonoids and other phenolics. Plant Physiol 126:1105–1115Bilger W, Rolland M, Nybakken L (2007) UV screening in higher plants induced by low temperature in the absence of UV-B radiation. Photochem Photobiol Sci 6:190–195Blumthaler M, Ambach M, Ellinger R (1997) Increase in solar UV radiation with altitude. J Photochem Photobiol B 39:130–134Boscaiu M, Lull C, Llinares J, Vicente O, Boira H (2013) Proline as a biochemical marker in relation to the ecology of two halophytic Juncus species. J Plant Ecol 6:177–186Bose J, Rodrigo-Moreno A, Shabala S (2013) ROS homeostasis in halophytes in the context of salinity stress tolerance. J Exp Bot 65:1241–1257Brown DE, Rashotte AM, Murphy AS, Normanly J, Tague BW, Peer WA, Taiz L, Muday GK (2001) Flavonoids act as a negative regulators of auxin transport in vivo in Arabidopsis. Plant Physiol 126:524–535Burchard P, Bilger W, Weissenböck G (2000) Contribution of hydroxycinnamates and flavonoids to epidermal shielding of UV-A and UV-B radiation in developing rye primary leaves as assessed by ultraviolet-induced chlorophyll fluorescence measurements. Plant Cell Environ 23:1373–1380Burriel F, Hernando V (1947) Nuevo método para determinar el fósforo asimilable en los suelos. Anales de Edafología Fisiología Vegetal 9:611–622Cheynier V, Comte G, Davies KM, Lattanzio V, Martens S (2013) Plant phenolics: recent advances on their biosynthesis, genetics, and ecophysiology. Plant Physiol Biochem 72:1–20Coman C, Rugina OD, Socaciu C (2012) Plants and natural compounds with antidiabetic action. Not Bot Horti Agrobo 40:314–325Di Ferdinando M, Brunetti C, Fini A, Tattini M (2012) Flavonoids as antioxidants in plants under abiotic stresses. In: Ahmad P, Prasad MNV (eds) Abiotic stress responses in plants: metabolism, productivity and sustainability. Springer, New York, pp 159–179Di Ferdinando M, Brunetti C, Agati G, Tattini M (2014) Multiple functions of polyphenols in plants inhabiting unfavourable Mediterranean areas. Environ Exper Bot 103:107–116FAO (1990) Management of gypsiferous soils. FAO Soils Bull, p 62Fini A, Brunetti C, Di Ferdinando M, Ferrini F, Tattini M (2011) Stress-induced flavonoid biosynthesis and the antioxidant machinery of plants. Plant Signal Behav 6:709–711Gil R, Lull C, Boscaiu M, Bautista I, Lidón A, Vicente O (2011) Soluble carbohydrates as osmolytes in several halophytes from a Mediterranean salt marsh. Not Bot Horti Agrobo 39:9–17Gil R, Bautista I, Boscaiu M, Lidón A, Wankhade S, Sánchez H, Llinares J, Vicente O (2014) Responses of five Mediterranean halophytes to seasonal changes in environmental conditions. AoB Plants 6: plu049Gould KS, Lister C (2006) Flavonoid function in plants. In: Andersen ØM, Marham KR (eds) Flavonoids, chemistry, biochemistry and application. CRC Press, Boca Raton, pp 397–442Hajimahmoodi M, Moghaddam G, Ranjbar AM, Khazani H, Sadeghi N, Oveisi MR, Jannat B (2013) Total phenolic, flavonoids, tannin content and antioxidant power of some Iranian pomegranate flower cultivars (Punica granatum L.). Am J Plant Sci 4:1815–1820Halliwell B (2006) Reactive species and antioxidants. Redox biology is a fundamental theme of aerobic life. Plant Physiol 141:312–322Harborne JB, Williams C (2000) Advances in flavonoid research since 1992. Phytochemistry 55:481–504Hernández I, Alegre L, Munné-Bosch S (2004) Drought-induced changes in flavonoids and other low molecular weight antioxidants in Cistus clusii grown under Mediterranean field conditions. Tree Physiol 24:1303–1311Hernández I, Alegre L, Van Breusegem F, Munné-Bosch S (2008) How relevant are flavonoids as antioxidants in plants? Trends Plant Sci 14:125–132Iwashina T (2000) The structure and distribution of the flavonoids in plants. J Plant Res 113:287–299Jaakola L, Määttä-Riihinen K, Kärenlampi S, Hohtola A (2004) Activation of flavonoid biosynthesis by solar radiation in bilberry (Vaccinium myrtillus L.) leaves. Planta 218:721–728Jenkins GI (2009) Signal transduction in responses to UB-B radiation. Annu Rev Plant Biol 60:407–431Jenkins GI, Long JC, Wade HK, Shenton MR, Bibikova TN (2001) UV and blue light signalling: pathways regulating chalcone synthase gene expression in Arabidopsis. New Phytol 151:121–131Kaulen H, Schell J, Kreuzaler F (1986) Light-induced expression of the chimeric chalcone synthase-NPTII gene in tobacco cells. EMBO J 5:1–8Kim DO, Jeong SW, Lee CY (2003) Antioxidant capacity of phenolic phytochemicals from various cultivars of plums. Food Chem 81:321–326Kirakosyan A, Seymour E, Kaufman PB, Warber S, Bolling S, Chang SC (2003) Antioxidant capacity of polyphenolic extracts from leaves of Crataegus laevigata and Crataegus monogyna (Hawthorn) subjected to drought and cold stress. J Agr Food Chem 51:3973–3976Knudssen D, Peterson GA, Pratt PF (1982) Lithium, Sodium and Potassium. In: Page AL et al (eds) Methods of soil analysis, chemical and microbiological properties. American Society of Agronomy, Madison, pp 225–246Koes RE, Spelt CE, Mol JNM (1989) The chalcone synthase multigene family of Petunia hybrida (V30): differential, light-regulated expression during flower development and UV light induction. Plant Mol Biol 12:213–225Körner C (1999) Alpine plant life. Functional plant ecology of high mountain ecosytems, BerlinKumar S, Pandey AK (2013) Chemistry and biological activities of flavonoids: an overview. Sci World J 2013:1–16Kuo S (1996) Phosphorus. In: Spark D (ed) Methods of soil analysis: chemical methods, part 3. American Society of Agronomy, Madison, pp 869–919Lavola A (1998) Accumulation of flavonoids and related compounds in birch induced by UV-B irradiance. Tree Physiol 18:53–58Li J, Ou-Lee TM, Raba R, Amundson RG, Last RL (1993) Arabidopsis flavonoid mutants are hypersensitive to UV-B radiation. Plant Cell 5:171–179Llinares JV, Bautista I, Donat MP, Lidón A, Lull C, Mayoral O, Wankhade S, Boscaiu M, Vicente O (2015) Responses to environmental stress in plants adapted to Mediterranean gypsum habitats. Not Sci Biol 7:34–44Marinova D, Ribarova F, Atanassova M (2005) Total phenolics and total flavonoids in Bulgarian fruits and vegetables. J Univ Chem Technol Metall 40:255–260Martens H, Naes T (1989) Multivariate calibration. Wiley, New YorkMurai Y, Takemura S, Takeda K, Kitajima K, Iwashina T (2009) Altitudinal variation of UV-absorbing compounds in Plantago asiatica. Biochem Syst Ecol 37:78–384Nakabayashi R, Yonekura-Sakakibara K, Urano K, Suzuki M, Yamada Y, Nishizawa T, Matsuda F, Kojima M, Sakakibara H, Shinozaki K, Michael AJ, Tohge T, Yamazaki M, Saito K (2014) Enhancement of oxidative and drought tolerance in Arabidopsis by overaccumulation of antioxidant flavonoids. Plant J 77:367–379Napoli CA, Fahy D, Wang HY, Taylor LP (1999) white anther: a petunia mutant that abolishes pollen flavonoid accumulation, induces male sterility, and is complemented by a chalcone synthase transgene. Plant Physiol 120:615–622Nechita A, Cotea VV, Nechita CB, Pincu RR, Mihai CT, Colibaba CL (2012) Study of cytostatic and cytotoxic activity of several polyphenolic extracts obtained from Vitis vinifera. Not Bot Horti Agrobo 40:216–221Nelson DW, Sommers LE (1982) Total carbon, organic carbon, and organic matter. In: Page AL et al (eds) Methods of soil analysis, chemical and microbiological properties. Soil Science Society of America, Madison, pp 539–577Nelson RE, Klameth LC, Nettleton WD (1978) Determining soil gypsum content and expressing properties of gypsiferous soils. Soil Sci Soc Am J 42:659–661Nile SH, Khobragade CN (2010) Antioxidant activity and flavonoid derivatives of Plumbago zeylanica. J Nat Prod 3:130–133Park HL, Lee SW, Jung KH, Hahn TR, Cho MH (2013) Transcriptomic analysis of UV-treated rice leaves reveals UV-induced phytoalexin biosynthetic pathways and their regulatory networks in rice. Phytochemistry 96:57–71Pękal A, Pyrzynska K (2014) Evaluation of aluminium complexation reaction for flavonoid content assay. Food Anal Method 7:1776–1782Pollastri S, Tattini M (2011) Flavonols: old compounds for old roles. Ann Bot 108:1225–1233Ravishankar D, Rajora AK, Greco F, Osborn HM (2013) Flavonoids as prospective compounds for anti-cancer therapy. Int J Biochem Cell B 45:2821–2831Rice-Evans CA, Miller NJ, Paganga G (1996) Structure-antioxidant activity relationships of flavonoids and phenolic acids. Free Radical Bio Med 20:933–956Rieger G, Müller M, Guttenberger H, Bucar F (2008) Influence of altitudinal variation on the content of phenolic compounds in wild populations of Calluna vulgaris, Sambucus nigra, and Vaccinium myrtillus. J Agric Food Chem 58:9080–9086Rivas-Martínez S, Rivas-Saenz S (1996–2009) Worldwide bioclimatic classification system. Phytosociological Research Center, Spain. http://www.globalbioclimatics.org . Accessed 1 July 2013Rohman A, Riyanto S, Yuniarti N, Saputra WR, Utami R, Mulatsih W (2010) Antioxidant activity, total phenolic, and total flavonoid of extracts and fractions of red fruit (Pandanus conoideus Lam). Int Food Res J 17:97–106Romano B, Pagano E, Montanaro V, Fortunato AL, Milic N, Borrelli F (2013) Novel insights into the pharmacology of flavonoids. Phytother Res 27:1588–1596Rozema J, van de Staaij J, Björn LO, Caldwell MM (1997) UV-B as an environmental factor in plant life: stress and regulation. Trends Ecol Evol 12:22–28Rozema J, Bjorn LO, Bornman JF, Gaberščik A, Häder DP, Trošt T, Germ M, Klisch M, Gröniger A, Sinha RP, Lebert M, He YY, Buffoni-Hall R, de Bakker NVJ, van de Staaij J, Meijkamp BB (2002) The role of UV-B radiation in aquatic and terrestrial ecosystems—an experimental and functional analysis of the evolution of UV-absorbing compounds. Photochem Photobiol B Biol 66:2–12Schulze-Lefert P, Dangl JL, Becker-André M, Hahlbrock K, Schulz W (1989) Inducible in vivo DNA footprints define sequences necessary for UV light activation of the parsley chalcone synthase gene. EMBO J 8:651–656Sena MM, Frighetto RTS, Valarini PJ, Tokeshi H, Poppi RJ (2002) Discrimination of management effects on soil parameters by using principal component analysis: a multivariate analysis case study. Soil Till Res 67:171–181Shulaev V, Oliver DJ (2006) Metabolic and proteomic markers for oxidative stress. New tools for reactive oxygen species research. Plant Physiol 141:367–372Singleton VL, Rossi JA Jr (1965) Colorimetry of total phenolics with phosphomolybdic phosphotungstic acid reagents. Am J EnolVitic 16:144–158Spitaler R, Winkler A, Lins I, Yanar S, Stuppner H, Zidorn C (2008) Altitudinal variation of phenolic contents in flowering heads of Arnica montana cv. ARBO: a 3-year comparison. J Chem Ecol 34:369–375Stapleton AE, Walbot V (1994) Flavonoids can protect maize DNA from the induction of UV radiation damage. Plant Physiol 105:881–889Takahashi M, Asada K (1988) Superoxide production in aprotic interior of chloroplast thylakoids. Arch Biochem Biophys 267:714–722Tattini M, Gravano E, Pinelli P, Mulinacci N, Romani A (2000) Flavonoids accumulate in leaves and glandular trichomes of Phillyrea latifolia exposed to excess solar radiation. New Phytol 148:69–77Tattini M, Galardi C, Pinelli P, Massai R, Remorini D, Agati G (2004) Differential accumulation of flavonoids and hydroxycinnamates in leaves of Ligustrum vulgare under excess light and drought stress. New Phytol 163:547–561Treutter D (2005) Significance of flavonoids in plant resistance and enhancement of their biosynthesis. Plant Biol 7:581–591Treutter D (2006) Significance of flavonoids in plant resistance: a review. Environ Chem Lett 4:147–157Van Breusegem F, Dat JF (2006) Reactive oxygen species in plant cell death. Plant Physiol 141:384–390Williams CA, Grayer RJ (2004) Anthocyanins and other flavonoids. Nat Prod Rep 21:539–573Winkel-Shirley B (2002) Biosynthesis of flavonoids and effect of stress. Curr Opin Plant Biol 5:218–223Ylstra B, Touraev A, Benito Moreno RM, Stöger E, van Tunen AA, Vicente O, Mol JNM, Heberle-Bors E (1992) Flavonols stimulate development, germination and tube growth of tobacco pollen. Plant Physiol 100:902–907Zhishen J, Mengcheng T, Jianming W (1999) The determination of flavonoid contents in mulberry and their scavenging effects on superoxide radicals. Food Chem 64:555–559Zidorn C, Schubert B, Stuppner H (2005) Altitudinal differences in the contents of phenolics in flowering heads of three members of the tribe Lactuceae (Asteraceae) occurring as introduced species in New Zealand. Biochem Syst Ecol 33:855–87

TRAIL promotes caspase-dependent pro-inflammatory responses via PKCδ activation by vascular smooth muscle cells

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is best known for its selective cytotoxicity against transformed tumor cells. Most non-transformed primary cells and several cancer cell lines are not only resistant to death receptor-induced apoptosis, but also subject to inflammatory responses in a nuclear factor-κB (NF-κB)-dependent manner. Although the involvement of TRAIL in a variety of vascular disorders has been proposed, the exact molecular mechanisms are unclear. Here, we aimed to delineate the role of TRAIL in inflammatory vascular response. We also sought possible molecular mechanisms to identify potential targets for the prevention and treatment of post-angioplastic restenosis and atherosclerosis. Treatment with TRAIL increased the expression of intercellular adhesion molecule-1 by primary human vascular smooth muscle cells via protein kinase C (PKC)δ and NF-κB activation. Following detailed analysis using various PKCδ mutants, we determined that PKCδ activation was mediated by caspase-dependent proteolysis. The protective role of PKCδ was further confirmed in post-traumatic vascular remodeling in vivo. We propose that the TRAIL/TRAIL receptor system has a critical role in the pathogenesis of inflammatory vascular disorders by transducing pro-inflammatory signals via caspase-mediated PKCδ cleavage and subsequent NF-κB activation