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Sample records for acid signaling molecules

  1. Pharmacology of bile acid receptors: Evolution of bile acids from simple detergents to complex signaling molecules.

    PubMed

    Copple, Bryan L; Li, Tiangang

    2016-02-01

    For many years, bile acids were thought to only function as detergents which solubilize fats and facilitate the uptake of fat-soluble vitamins in the intestine. Many early observations; however, demonstrated that bile acids regulate more complex processes, such as bile acids synthesis and immune cell function through activation of signal transduction pathways. These studies were the first to suggest that receptors may exist for bile acids. Ultimately, seminal studies by many investigators led to the discovery of several bile acid-activated receptors including the farnesoid X receptor, the vitamin D receptor, the pregnane X receptor, TGR5, α5 β1 integrin, and sphingosine-1-phosphate receptor 2. Several of these receptors are expressed outside of the gastrointestinal system, indicating that bile acids may have diverse functions throughout the body. Characterization of the functions of these receptors over the last two decades has identified many important roles for these receptors in regulation of bile acid synthesis, transport, and detoxification; regulation of glucose utilization; regulation of fatty acid synthesis and oxidation; regulation of immune cell function; regulation of energy expenditure; and regulation of neural processes such as gastric motility. Through these many functions, bile acids regulate many aspects of digestion ranging from uptake of essential vitamins to proper utilization of nutrients. Accordingly, within a short time period, bile acids moved beyond simple detergents and into the realm of complex signaling molecules. Because of the important processes that bile acids regulate through activation of receptors, drugs that target these receptors are under development for the treatment of several diseases, including cholestatic liver disease and metabolic syndrome. In this review, we will describe the various bile acid receptors, the signal transduction pathways activated by these receptors, and briefly discuss the physiological processes that

  2. Control of Biofilms with the Fatty Acid Signaling Molecule cis-2-Decenoic Acid

    PubMed Central

    Marques, Cláudia N. H.; Davies, David G.; Sauer, Karin

    2015-01-01

    Biofilms are complex communities of microorganisms in organized structures attached to surfaces. Importantly, biofilms are a major cause of bacterial infections in humans, and remain one of the most significant challenges to modern medical practice. Unfortunately, conventional therapies have shown to be inadequate in the treatment of most chronic biofilm infections based on the extraordinary innate tolerance of biofilms to antibiotics. Antagonists of quorum sensing signaling molecules have been used as means to control biofilms. QS and other cell-cell communication molecules are able to revert biofilm tolerance, prevent biofilm formation and disrupt fully developed biofilms, albeit with restricted effectiveness. Recently however, it has been demonstrated that Pseudomonas aeruginosa produces a small messenger molecule cis-2-decenoic acid (cis-DA) that shows significant promise as an effective adjunctive to antimicrobial treatment of biofilms. This molecule is responsible for induction of the native biofilm dispersion response in a range of Gram-negative and Gram-positive bacteria and in yeast, and has been shown to reverse persistence, increase microbial metabolic activity and significantly enhance the cidal effects of conventional antimicrobial agents. In this manuscript, the use of cis-2-decenoic acid as a novel agent for biofilm control is discussed. Stimulating the biofilm dispersion response as a novel antimicrobial strategy holds significant promise for enhanced treatment of infections and in the prevention of biofilm formation. PMID:26610524

  3. Oxalic acid: a signal molecule for fungus-feeding bacteria of the genus Collimonas?

    PubMed

    Rudnick, M B; van Veen, J A; de Boer, W

    2015-10-01

    Mycophagous (=fungus feeding) soil bacteria of the genus Collimonas have been shown to colonize and grow on hyphae of different fungal hosts as the only source of energy and carbon. The ability to exploit fungal nutrient resources might require a strategy for collimonads to sense fungi in the soil matrix. Oxalic acid is ubiquitously secreted by soil fungi, serving different purposes. In this study, we investigated the possibility that collimonads might use oxalic acid secretion to localize a fungal host and move towards it. We first confirmed earlier indications that collimonads have a very limited ability to use oxalic acid as growth substrate. In a second step, with using different assays, we show that oxalic acid triggers bacterial movement in such a way that accumulation of cells can be expected at micro-sites with high free oxalic acid concentrations. Based on these observations we propose that oxalic acid functions as a signal molecule to guide collimonads to hyphal tips, the mycelial zones that are most sensitive for mycophagous bacterial attack. PMID:25858310

  4. Microfluidic study of the chemotactic response of Escherichia coli to amino acids, signaling molecules and secondary metabolites.

    PubMed

    Nagy, Krisztina; Sipos, Orsolya; Valkai, Sándor; Gombai, Éva; Hodula, Orsolya; Kerényi, Ádám; Ormos, Pál; Galajda, Péter

    2015-07-01

    Quorum sensing and chemotaxis both affect bacterial behavior on the population level. Chemotaxis shapes the spatial distribution of cells, while quorum sensing realizes a cell-density dependent gene regulation. An interesting question is if these mechanisms interact on some level: Does quorum sensing, a density dependent process, affect cell density itself via chemotaxis? Since quorum sensing often spans across species, such a feedback mechanism may also exist between multiple species. We constructed a microfluidic platform to study these questions. A flow-free, stable linear chemical gradient is formed in our device within a few minutes that makes it suitable for sensitive testing of chemoeffectors: we showed that the amino acid lysine is a weak chemoattractant for Escherichia coli, while arginine is neutral. We studied the effect of quorum sensing signal molecules of Pseudomonas aeruginosa on E. coli chemotaxis. Our results show that N-(3-oxododecanoyl)-homoserine lactone (oxo-C12-HSL) and N-(butryl)-homoserine lactone (C4-HSL) are attractants. Furthermore, we tested the chemoeffector potential of pyocyanin and pyoverdine, secondary metabolites under a quorum sensing control. Pyocyanin is proved to be a weak attractant while pyoverdine are repellent. We demonstrated the usability of the device in co-culturing experiments, where we showed that various factors released by P. aeruginosa affect the dynamic spatial rearrangement of a neighboring E. coli population, while surface adhesion of the cells is also modulated. PMID:26339306

  5. The Fatty Acid Signaling Molecule cis-2-Decenoic Acid Increases Metabolic Activity and Reverts Persister Cells to an Antimicrobial-Susceptible State

    PubMed Central

    Morozov, Aleksey; Planzos, Penny; Zelaya, Hector M.

    2014-01-01

    Persister cells, which are tolerant to antimicrobials, contribute to biofilm recalcitrance to therapeutic agents. In turn, the ability to kill persister cells is believed to significantly improve efforts in eradicating biofilm-related, chronic infections. While much research has focused on elucidating the mechanism(s) by which persister cells form, little is known about the mechanism or factors that enable persister cells to revert to an active and susceptible state. Here, we demonstrate that cis-2-decenoic acid (cis-DA), a fatty acid signaling molecule, is able to change the status of Pseudomonas aeruginosa and Escherichia coli persister cells from a dormant to a metabolically active state without an increase in cell number. This cell awakening is supported by an increase of the persister cells' respiratory activity together with changes in protein abundance and increases of the transcript expression levels of several metabolic markers, including acpP, 16S rRNA, atpH, and ppx. Given that most antimicrobials target actively growing cells, we also explored the effect of cis-DA on enhancing antibiotic efficacy in killing persister cells due to their inability to keep a persister cell state. Compared to antimicrobial treatment alone, combinational treatments of persister cell subpopulations with antimicrobials and cis-DA resulted in a significantly greater decrease in cell viability. In addition, the presence of cis-DA led to a decrease in the number of persister cells isolated. We thus demonstrate the ability of a fatty acid signaling molecule to revert bacterial cells from a tolerant phenotype to a metabolically active, antimicrobial-sensitive state. PMID:25192989

  6. Dialkylresorcinols as bacterial signaling molecules

    PubMed Central

    Brameyer, Sophie; Kresovic, Darko; Bode, Helge B.; Heermann, Ralf

    2015-01-01

    It is well recognized that bacteria communicate via small diffusible molecules, a process termed quorum sensing. The best understood quorum sensing systems are those that use acylated homoserine lactones (AHLs) for communication. The prototype of those systems consists of a LuxI-like AHL synthase and a cognate LuxR receptor that detects the signal. However, many proteobacteria possess LuxR receptors, yet lack any LuxI-type synthase, and thus these receptors are referred to as LuxR orphans or solos. In addition to the well-known AHLs, little is known about the signaling molecules that are sensed by LuxR solos. Here, we describe a novel cell–cell communication system in the insect and human pathogen Photorhabdus asymbiotica. We identified the LuxR homolog PauR to sense dialkylresorcinols (DARs) and cyclohexanediones (CHDs) instead of AHLs as signals. The DarABC synthesis pathway produces the molecules, and the entire system emerged as important for virulence. Moreover, we have analyzed more than 90 different Photorhabdus strains by HPLC/MS and showed that these DARs and CHDs are specific to the human pathogen P. asymbiotica. On the basis of genomic evidence, 116 other bacterial species are putative DAR producers, among them many human pathogens. Therefore, we discuss the possibility of DARs as novel and widespread bacterial signaling molecules and show that bacterial cell–cell communication goes far beyond AHL signaling in nature. PMID:25550519

  7. Signaling Molecules: Hydrogen Sulfide and Polysulfide

    PubMed Central

    2015-01-01

    Abstract Significance: Hydrogen sulfide (H2S) has been recognized as a signaling molecule as well as a cytoprotectant. It modulates neurotransmission, regulates vascular tone, and protects various tissues and organs, including neurons, the heart, and kidneys, from oxidative stress and ischemia-reperfusion injury. H2S is produced from l-cysteine by cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3MST) along with cysteine aminotransferase. Recent Advances: In addition to these enzymes, we recently identified a novel pathway to produce H2S from d-cysteine, which involves d-amino acid oxidase (DAO) along with 3MST. These enzymes are localized in the cytoplasm, mitochondria, and peroxisomes. However, some enzymes translocate to organelles under specific conditions. Moreover, H2S-derived potential signaling molecules such as polysulfides and HSNO have been identified. Critical Issues: The physiological stimulations, which trigger the production of H2S and its derivatives and maintain their local levels, remain unclear. Future Directions: Understanding the regulation of the H2S production and H2S-derived signaling molecules and the specific stimuli that induce their release will provide new insights into the biology of H2S and therapeutic development in diseases involving these substances. Antioxid. Redox Signal. 22, 362–376. PMID:24800864

  8. Hydrogen sulfide acts as a downstream signal molecule in salicylic acid-induced heat tolerance in maize (Zea mays L.) seedlings.

    PubMed

    Li, Zhong-Guang; Xie, Lin-Run; Li, Xiao-Juan

    2015-04-01

    Salicylic acid (SA), 2-hydroxy benzoic acid, is a small phenolic compound with multifunction that is involved in plant growth, development, and the acquisition of stress tolerance. In recent years, hydrogen sulfide (H2S) has been found to have similar functions, but cross talk between SA and H2S in the acquisition of heat tolerance is not clear. In this study, pretreatment of maize seedlings with SA improved the survival percentage of seedlings under heat stress, indicating that SA pretreatment could improve the heat tolerance of maize seedlings. In addition, treatment with SA enhanced the activity of L-cysteine desulfhydrase (L-DES), a key enzyme in H2S biosynthesis, which in turn induced accumulation of endogenous H2S. Interestingly, SA-induced heat tolerance was enhanced by addition of NaHS, a H2S donor, but weakened by specific inhibitors of H2S biosynthesis DL-propargylglycine (PAG) and its scavenger hydroxylamine (HT). Furthermore, pretreatment with paclobutrazol (PAC) and 2-aminoindan-2-phosphonic acid (AIP), inhibitors of SA biosynthesis, had no significant effect on NaHS-induced heat tolerance of maize seedlings. Similarly, significant change in the activities of phenylalanine ammonia lyase (PAL) and benzoic-acid-2-hydroxylase (BA2H), the key enzymes in SA biosynthesis, and the content of endogenous SA, was not observed in maize seedlings by NaHS treatment. All of the above-mentioned results suggest that SA pretreatment could improve the heat tolerance of maize seedlings, and H2S might be a novel downstream signal molecule in SA-induced heat tolerance. PMID:25727780

  9. Geranyl diphosphate synthase molecules, and nucleic acid molecules encoding same

    SciTech Connect

    Croteau, Rodney Bruce; Burke, Charles Cullen

    2008-06-24

    In one aspect, the present invention provides isolated nucleic acid molecules that each encode a geranyl diphosphate synthase protein, wherein each isolated nucleic acid molecule hybridizes to a nucleic acid molecule consisting of the sequence set forth in SEQ ID NO:1 under conditions of 5.times.SSC at 45.degree. C. for one hour. The present invention also provides isolated geranyl diphosphate synthase proteins, and methods for altering the level of expression of geranyl diphosphate synthase protein in a host cell.

  10. Glutathione as a signaling molecule: another challenge to pathogens.

    PubMed

    Ghanta, Srijani; Chattopadhyay, Sharmila

    2011-06-01

    Plants harbor a variety of signaling molecules which are members of a vast array of signaling networks in maintaining their physiological balance. The well known members up till now are salicylic acid (SA), jasmonic acid (JA), ethylene (ET), abscissic acid (ABA) and reactive oxygen species (ROS) which are employed by plants for their adaptation to various environmental stresses in order to survive. GSH is gradually gaining importance and becoming a molecule of interest to a number of researchers especially in relation to plant defense to pathogens. Although the role of GSH in plant defense has long been known, a dearth of information still exists regarding the mechanism underlying this defense response. This review highlights on the progress made in the cross-communication of GSH with other established signaling molecules through which GSH acts in abating biotic stress PMID:21969955

  11. Polypetide signaling molecules in plant development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Intercellular communication mediated by small signaling molecules is a key mechanism for coordinating plant growth and development. In the past few years, polypeptide signals have been shown to play prominent roles in processes as diverse as shoot and root meristem maintenance, vascular differentiat...

  12. Single-Molecule Imaging of Cellular Signaling

    NASA Astrophysics Data System (ADS)

    De Keijzer, Sandra; Snaar-Jagalska, B. Ewa; Spaink, Herman P.; Schmidt, Thomas

    Single-molecule microscopy is an emerging technique to understand the function of a protein in the context of its natural environment. In our laboratory this technique has been used to study the dynamics of signal transduction in vivo. A multitude of signal transduction cascades are initiated by interactions between proteins in the plasma membrane. These cascades start by binding a ligand to its receptor, thereby activating downstream signaling pathways which finally result in complex cellular responses. To fully understand these processes it is important to study the initial steps of the signaling cascades. Standard biological assays mostly call for overexpression of the proteins and high concentrations of ligand. This sets severe limits to the interpretation of, for instance, the time-course of the observations, given the large temporal spread caused by the diffusion-limited binding processes. Methods and limitations of single-molecule microscopy for the study of cell signaling are discussed on the example of the chemotactic signaling of the slime-mold Dictyostelium discoideum. Single-molecule studies, as reviewed in this chapter, appear to be one of the essential methodologies for the full spatiotemporal clarification of cellular signaling, one of the ultimate goals in cell biology.

  13. Hydrogen sulfide and polysulfides as signaling molecules.

    PubMed

    Kimura, Hideo

    2015-01-01

    Hydrogen sulfide (H2S) is a familiar toxic gas that smells of rotten eggs. After the identification of endogenous H2S in the mammalian brain two decades ago, studies of this molecule uncovered physiological roles in processes such as neuromodulation, vascular tone regulation, cytoprotection against oxidative stress, angiogenesis, anti-inflammation, and oxygen sensing. Enzymes that produce H2S, such as cystathionine β-synthase, cystathionine γ-lyase, and 3-mercaptopyruvate sulfurtransferase have been studied intensively and well characterized. Polysulfides, which have a higher number of inner sulfur atoms than that in H2S, were recently identified as potential signaling molecules that can activate ion channels, transcription factors, and tumor suppressors with greater potency than that of H2S. This article focuses on our contribution to the discovery of these molecules and their metabolic pathways and mechanisms of action. PMID:25864468

  14. Hydrogen sulfide and polysulfides as signaling molecules

    PubMed Central

    KIMURA, Hideo

    2015-01-01

    Hydrogen sulfide (H2S) is a familiar toxic gas that smells of rotten eggs. After the identification of endogenous H2S in the mammalian brain two decades ago, studies of this molecule uncovered physiological roles in processes such as neuromodulation, vascular tone regulation, cytoprotection against oxidative stress, angiogenesis, anti-inflammation, and oxygen sensing. Enzymes that produce H2S, such as cystathionine β-synthase, cystathionine γ-lyase, and 3-mercaptopyruvate sulfurtransferase have been studied intensively and well characterized. Polysulfides, which have a higher number of inner sulfur atoms than that in H2S, were recently identified as potential signaling molecules that can activate ion channels, transcription factors, and tumor suppressors with greater potency than that of H2S. This article focuses on our contribution to the discovery of these molecules and their metabolic pathways and mechanisms of action. PMID:25864468

  15. Method for sequencing nucleic acid molecules

    DOEpatents

    Korlach, Jonas; Webb, Watt W.; Levene, Michael; Turner, Stephen; Craighead, Harold G.; Foquet, Mathieu

    2006-05-30

    The present invention is directed to a method of sequencing a target nucleic acid molecule having a plurality of bases. In its principle, the temporal order of base additions during the polymerization reaction is measured on a molecule of nucleic acid, i.e. the activity of a nucleic acid polymerizing enzyme on the template nucleic acid molecule to be sequenced is followed in real time. The sequence is deduced by identifying which base is being incorporated into the growing complementary strand of the target nucleic acid by the catalytic activity of the nucleic acid polymerizing enzyme at each step in the sequence of base additions. A polymerase on the target nucleic acid molecule complex is provided in a position suitable to move along the target nucleic acid molecule and extend the oligonucleotide primer at an active site. A plurality of labelled types of nucleotide analogs are provided proximate to the active site, with each distinguishable type of nucleotide analog being complementary to a different nucleotide in the target nucleic acid sequence. The growing nucleic acid strand is extended by using the polymerase to add a nucleotide analog to the nucleic acid strand at the active site, where the nucleotide analog being added is complementary to the nucleotide of the target nucleic acid at the active site. The nucleotide analog added to the oligonucleotide primer as a result of the polymerizing step is identified. The steps of providing labelled nucleotide analogs, polymerizing the growing nucleic acid strand, and identifying the added nucleotide analog are repeated so that the nucleic acid strand is further extended and the sequence of the target nucleic acid is determined.

  16. Method for sequencing nucleic acid molecules

    DOEpatents

    Korlach, Jonas; Webb, Watt W.; Levene, Michael; Turner, Stephen; Craighead, Harold G.; Foquet, Mathieu

    2006-06-06

    The present invention is directed to a method of sequencing a target nucleic acid molecule having a plurality of bases. In its principle, the temporal order of base additions during the polymerization reaction is measured on a molecule of nucleic acid, i.e. the activity of a nucleic acid polymerizing enzyme on the template nucleic acid molecule to be sequenced is followed in real time. The sequence is deduced by identifying which base is being incorporated into the growing complementary strand of the target nucleic acid by the catalytic activity of the nucleic acid polymerizing enzyme at each step in the sequence of base additions. A polymerase on the target nucleic acid molecule complex is provided in a position suitable to move along the target nucleic acid molecule and extend the oligonucleotide primer at an active site. A plurality of labelled types of nucleotide analogs are provided proximate to the active site, with each distinguishable type of nucleotide analog being complementary to a different nucleotide in the target nucleic acid sequence. The growing nucleic acid strand is extended by using the polymerase to add a nucleotide analog to the nucleic acid strand at the active site, where the nucleotide analog being added is complementary to the nucleotide of the target nucleic acid at the active site. The nucleotide analog added to the oligonucleotide primer as a result of the polymerizing step is identified. The steps of providing labelled nucleotide analogs, polymerizing the growing nucleic acid strand, and identifying the added nucleotide analog are repeated so that the nucleic acid strand is further extended and the sequence of the target nucleic acid is determined.

  17. Nucleic Acids as Information Molecules.

    ERIC Educational Resources Information Center

    McInerney, Joseph D.

    1996-01-01

    Presents an activity that aims at enabling students to recognize that DNA and RNA are information molecules whose function is to store, copy, and make available the information in biological systems, without feeling overwhelmed by the specialized vocabulary and the minutia of the central dogma. (JRH)

  18. Sulfide as a signaling molecule in autophagy

    PubMed Central

    Gotor, Cecilia; García, Irene; Crespo, José L.; Romero, Luis C.

    2013-01-01

    Hydrogen sulfide is already recognized as an important signaling molecule in mammalian systems, and emerging data suggest that H2S is a signaling molecule just as important as nitric oxide (NO) and H2O2 in plants. Although sulfide is generated in chloroplasts and mitochondria, it is present predominantly in the charged HS- form due to the basic pH inside both organelles, thus requiring an active transporter, which is yet to be identified, to be released. In Arabidopsis, we found that the cytosolic L-cysteine desulfhydrase DES1 is involved in the degradation of cysteine, and therefore responsible for the generation of H2S in this cellular compartment. DES1 deficiency leads to the induction of autophagy. Moreover, we have demonstrated that sulfide in particular exerts a general effect on autophagy through negative regulation, in a way unrelated to nutrient deficiency. The mechanisms of H2S action and its molecular targets are largely unknown, although in animal systems, protein S-sulfhydration has been proposed as a mechanism for sulfide-mediated signaling. PMID:23328265

  19. Alpha2,6-sialic acid on platelet endothelial cell adhesion molecule (PECAM) regulates its homophilic interactions and downstream antiapoptotic signaling.

    PubMed

    Kitazume, Shinobu; Imamaki, Rie; Ogawa, Kazuko; Komi, Yusuke; Futakawa, Satoshi; Kojima, Soichi; Hashimoto, Yasuhiro; Marth, Jamey D; Paulson, James C; Taniguchi, Naoyuki

    2010-02-26

    Antiangiogenesis therapies are now part of the standard repertoire of cancer therapies, but the mechanisms for the proliferation and survival of endothelial cells are not fully understood. Although endothelial cells are covered with a glycocalyx, little is known about how endothelial glycosylation regulates endothelial functions. Here, we show that alpha2,6-sialic acid is necessary for the cell-surface residency of platelet endothelial cell adhesion molecule (PECAM), a member of the immunoglobulin superfamily that plays multiple roles in cell adhesion, mechanical stress sensing, antiapoptosis, and angiogenesis. As a possible underlying mechanism, we found that the homophilic interactions of PECAM in endothelial cells were dependent on alpha2,6-sialic acid. We also found that the absence of alpha2,6-sialic acid down-regulated the tyrosine phosphorylation of PECAM and recruitment of Src homology 2 domain-containing protein-tyrosine phosphatase 2 and rendered the cells more prone to mitochondrion-dependent apoptosis, as evaluated using PECAM- deficient endothelial cells. The present findings open up a new possibility that modulation of glycosylation could be one of the promising strategies for regulating angiogenesis. PMID:20048157

  20. Salicylic acid signaling inhibits apoplastic reactive oxygen species signaling

    PubMed Central

    2014-01-01

    Background Reactive oxygen species (ROS) are used by plants as signaling molecules during stress and development. Given the amount of possible challenges a plant face from their environment, plants need to activate and prioritize between potentially conflicting defense signaling pathways. Until recently, most studies on signal interactions have focused on phytohormone interaction, such as the antagonistic relationship between salicylic acid (SA)-jasmonic acid and cytokinin-auxin. Results In this study, we report an antagonistic interaction between SA signaling and apoplastic ROS signaling. Treatment with ozone (O3) leads to a ROS burst in the apoplast and induces extensive changes in gene expression and elevation of defense hormones. However, Arabidopsis thaliana dnd1 (defense no death1) exhibited an attenuated response to O3. In addition, the dnd1 mutant displayed constitutive expression of defense genes and spontaneous cell death. To determine the exact process which blocks the apoplastic ROS signaling, double and triple mutants involved in various signaling pathway were generated in dnd1 background. Simultaneous elimination of SA-dependent and SA-independent signaling components from dnd1 restored its responsiveness to O3. Conversely, pre-treatment of plants with SA or using mutants that constitutively activate SA signaling led to an attenuation of changes in gene expression elicited by O3. Conclusions Based upon these findings, we conclude that plants are able to prioritize the response between ROS and SA via an antagonistic action of SA and SA signaling on apoplastic ROS signaling. PMID:24898702

  1. Identification of cell density signal molecule

    DOEpatents

    Schwarz, R.I.

    1998-04-21

    Disclosed herein is a novel proteinaceous cell density signal molecule (CDS) between 25 and 35 kD, which is secreted by fibroblastic primary avian tendon cells in culture, and causes the cells to self-regulate their proliferation and the expression of differentiated function. It effects an increase of procollagen production in avian tendon cell cultures of ten fold while proliferation rates are decreased. CDS, and the antibodies which recognize them, are important for the development of diagnostics and treatments for injuries and diseases involving connective tissues, particularly tendon. Also disclosed are methods of production and use. 2 figs.

  2. Identification of cell density signal molecule

    DOEpatents

    Schwarz, Richard I.

    1998-01-01

    Disclosed herein is a novel proteinaceous cell density signal molecule (CDS) between 25 and 35 kD, which is secreted by fibroblastic primary avian tendon cells in culture, and causes the cells to self-regulate their proliferation and the expression of differentiated function. It effects an increase of procollagen production in avian tendon cell cultures of ten fold while proliferation rates are decreased. CDS, and the antibodies which recognize them, are important for the development of diagnostics and treatments for injuries and diseases involving connective tissues, particularly tendon. Also disclosed are methods of production and use.

  3. Carotenoids as signaling molecules in cardiovascular biology

    PubMed Central

    Barzegari, Abolfazl; Pavon-Djavid, Graciela

    2014-01-01

    Oxidative stress and inflammation play important roles in the etiology of cardiovascular disease (CVD). Thus, natural antioxidant carotenoids existing in fruits and vegetables could have a significant role in the prevention of CVD. Nevertheless, clinical data are conflicting about the positive effect of some antioxidant carotenoids in reducing cardiovascular morbidity and mortality. Many biological actions of carotenoids have been attributed to their antioxidant effect; however, the precise mechanism by which carotenoids produce their beneficial effects is still under discussion. They might modulate molecular pathways involved in cell proliferation, acting at Akt, tyrosine kinases, mitogen activated protein kinase (MAP kinase) and growth factor signaling cascades. Screening for a promising cardiovascular protective carotenoids therefore might be performed in vitro and in vivo with caution in cross-interaction with other molecules involved in signaling pathways especially those affecting microRNAs, performing a role in molecular modulation of cardiovascular cells. PMID:25337462

  4. Plant peroxisomes as a source of signalling molecules.

    PubMed

    Nyathi, Yvonne; Baker, Alison

    2006-12-01

    Peroxisomes are pleiomorphic, metabolically plastic organelles. Their essentially oxidative function led to the adoption of the name 'peroxisome'. The dynamic and diverse nature of peroxisome metabolism has led to the realisation that peroxisomes are an important source of signalling molecules that can function to integrate cellular activity and multicellular development. In plants defence against predators and a hostile environment is of necessity a metabolic and developmental response--a plant has no place to hide. Mutant screens are implicating peroxisomes in disease resistance and signalling in response to light. Characterisation of mutants disrupted in peroxisomal beta-oxidation has led to a growing appreciation of the importance of this pathway in the production of jasmonic acid, conversion of indole butyric acid to indole acetic acid and possibly in the production of other signalling molecules. Likewise the role of peroxisomes in the production and detoxification of reactive oxygen, and possibly reactive nitrogen species and changes in redox status, suggests considerable scope for peroxisomes to contribute to perception and response to a wide range of biotic and abiotic stresses. Whereas the peroxisome is the sole site of beta-oxidation in plants, the production and detoxification of ROS in many cell compartments makes the specific contribution of the peroxisome much more difficult to establish. However progress in identifying peroxisome specific isoforms of enzymes associated with ROS metabolism should allow a more definitive assessment of these contributions in the future. PMID:17030442

  5. Carbon Monoxide: An Essential Signalling Molecule

    NASA Astrophysics Data System (ADS)

    Mann, Brian E.

    Carbon monoxide (CO), like nitric oxide (NO), is an essential signalling molecule in humans. It is active in the cardiovascular system as a vasodilator. In addition, CO possesses anti-inflammatory, anti-apoptotic and anti-proliferative properties and protects tissues from hypoxia and reperfusion injury. Some of its applications in animal models include suppression of organ graft rejection and safeguarding the heart during reperfusion after cardiopulmonary bypass surgery. CO also suppresses arteriosclerotic lesions following angioplasty, reverses established pulmonary hypertension and mitigates the development of post-operative ileus in the murine small intestine and the development of cerebral malaria in mice as well as graft-induced intimal hyperplasia in pigs. There have been several clinical trials using air-CO mixtures for the treatment of lung-, heart-, kidney- and abdominal-related diseases. This review examines the research involving the development of classes of compounds (with particular emphasis on metal carbonyls) that release CO, which could be used in clinically relevant conditions. The review is drawn not only from published papers in the chemical literature but also from the extensive biological literature and patents on CO-releasing molecules (CO-RMs).

  6. Sugar amino acids in designing new molecules.

    PubMed

    Chakraborty, Tushar Kanti; Srinivasu, Pothukanuri; Tapadar, Subhasish; Mohan, Bajjuri Krishna

    2005-03-01

    Emulating the basic principles followed by nature to build its vast repertoire of biomolecules, organic chemists are developing many novel multifunctional building blocks and using them to create 'nature-like' and yet unnatural organic molecules. Sugar amino acids constitute an important class of such polyfunctional scaffolds where the carboxyl, amino and hydroxyl termini provide an excellent opportunity to organic chemists to create structural diversities akin to Nature's molecular arsenal. This article describes some of our works on various sugar amino acids and many other related building blocks, like furan amino acids, pyrrole amino acids etc. used in wide-ranging peptidomimetic studies. PMID:16133829

  7. Featured Molecules: Ascorbic Acid and Methylene Blue

    NASA Astrophysics Data System (ADS)

    Coleman, William F.; Wildman, Randall J.

    2003-05-01

    The WebWare molecules of the month for May are featured in several articles in this issue. "Arsenic: Not So Evil After All?" discusses the pharmaceutical uses of methylene blue and its development as the first synthetic drug used against a specific disease. The JCE Classroom Activity "Out of the Blue" and the article "Greening the Blue Bottle" feature methylene blue and ascorbic acid as two key ingredients in the formulation of the blue bottle. You can also see a colorful example of these two molecules in action on the cover. "Sailing on the 'C': A Vitamin Titration with a Twist" describes an experiment to determine the vitamin C (ascorbic acid) content of citrus fruits and challenges students, as eighteenth-century sea captains, to decide the best fruit to take on a long voyage. Fully manipulable (Chime) versions of these and other molecules are available at Only@JCE Online.

  8. Conserved nematode signalling molecules elicit plant defenses and pathogen resistance

    PubMed Central

    Manosalva, Patricia; Manohar, Murli; von Reuss, Stephan H.; Chen, Shiyan; Koch, Aline; Kaplan, Fatma; Choe, Andrea; Micikas, Robert J.; Wang, Xiaohong; Kogel, Karl-Heinz; Sternberg, Paul W.; Williamson, Valerie M.; Schroeder, Frank C.; Klessig, Daniel F.

    2015-01-01

    Plant-defense responses are triggered by perception of conserved microbe-associated molecular patterns (MAMPs), for example, flagellin or peptidoglycan. However, it remained unknown whether plants can detect conserved molecular patterns derived from plant-parasitic animals, including nematodes. Here we show that several genera of plant-parasitic nematodes produce small molecules called ascarosides, an evolutionarily conserved family of nematode pheromones. Picomolar to micromolar concentrations of ascr#18, the major ascaroside in plant-parasitic nematodes, induce hallmark defense responses including the expression of genes associated with MAMP-triggered immunity, activation of mitogen-activated protein kinases, as well as salicylic acid- and jasmonic acid-mediated defense signalling pathways. Ascr#18 perception increases resistance in Arabidopsis, tomato, potato and barley to viral, bacterial, oomycete, fungal and nematode infections. These results indicate that plants recognize ascarosides as a conserved molecular signature of nematodes. Using small-molecule signals such as ascarosides to activate plant immune responses has potential utility to improve economic and environmental sustainability of agriculture. PMID:26203561

  9. Conserved nematode signalling molecules elicit plant defenses and pathogen resistance.

    PubMed

    Manosalva, Patricia; Manohar, Murli; von Reuss, Stephan H; Chen, Shiyan; Koch, Aline; Kaplan, Fatma; Choe, Andrea; Micikas, Robert J; Wang, Xiaohong; Kogel, Karl-Heinz; Sternberg, Paul W; Williamson, Valerie M; Schroeder, Frank C; Klessig, Daniel F

    2015-01-01

    Plant-defense responses are triggered by perception of conserved microbe-associated molecular patterns (MAMPs), for example, flagellin or peptidoglycan. However, it remained unknown whether plants can detect conserved molecular patterns derived from plant-parasitic animals, including nematodes. Here we show that several genera of plant-parasitic nematodes produce small molecules called ascarosides, an evolutionarily conserved family of nematode pheromones. Picomolar to micromolar concentrations of ascr#18, the major ascaroside in plant-parasitic nematodes, induce hallmark defense responses including the expression of genes associated with MAMP-triggered immunity, activation of mitogen-activated protein kinases, as well as salicylic acid- and jasmonic acid-mediated defense signalling pathways. Ascr#18 perception increases resistance in Arabidopsis, tomato, potato and barley to viral, bacterial, oomycete, fungal and nematode infections. These results indicate that plants recognize ascarosides as a conserved molecular signature of nematodes. Using small-molecule signals such as ascarosides to activate plant immune responses has potential utility to improve economic and environmental sustainability of agriculture. PMID:26203561

  10. Lysophosphatidic acid signalling in development.

    PubMed

    Sheng, Xiaoyan; Yung, Yun C; Chen, Allison; Chun, Jerold

    2015-04-15

    Lysophosphatidic acid (LPA) is a bioactive phospholipid that is present in all tissues examined to date. LPA signals extracellularly via cognate G protein-coupled receptors to mediate cellular processes such as survival, proliferation, differentiation, migration, adhesion and morphology. These LPA-influenced processes impact many aspects of organismal development. In particular, LPA signalling has been shown to affect fertility and reproduction, formation of the nervous system, and development of the vasculature. Here and in the accompanying poster, we review the developmentally related features of LPA signalling. PMID:25852197

  11. Lysophosphatidic Acid signaling in the nervous system.

    PubMed

    Yung, Yun C; Stoddard, Nicole C; Mirendil, Hope; Chun, Jerold

    2015-02-18

    The brain is composed of many lipids with varied forms that serve not only as structural components but also as essential signaling molecules. Lysophosphatidic acid (LPA) is an important bioactive lipid species that is part of the lysophospholipid (LP) family. LPA is primarily derived from membrane phospholipids and signals through six cognate G protein-coupled receptors (GPCRs), LPA1-6. These receptors are expressed on most cell types within central and peripheral nervous tissues and have been functionally linked to many neural processes and pathways. This Review covers a current understanding of LPA signaling in the nervous system, with particular focus on the relevance of LPA to both physiological and diseased states. PMID:25695267

  12. Nanoconstructions Based on Spatially Ordered Nucleic Acid Molecules

    NASA Astrophysics Data System (ADS)

    Yevdokimov, Yu. M.

    Different strategies for the design of nanoconstructions whose building blocks are both linear molecules of double-stranded nucleic acids and nucleic acid molecules fixed in the spatial structure of particles of liquid-crystalline dispersions are described.

  13. Piperazic acid derivatives inhibit Gli1 in Hedgehog signaling pathway.

    PubMed

    Khatra, Harleen; Kundu, Jayanta; Khan, Pragya Paramita; Duttagupta, Indranil; Pattanayak, Sankha; Sinha, Surajit

    2016-09-15

    Piperazic acid, a non-proteinogenic amino acid, found in complex secondary metabolites and peptide natural substances, has shown down regulation of Gli1 expression in Hedgehog signaling pathway in cell based assays. Further structure activity relationship study indicated that amide derivatives of piperazic acid are more potent than piperazic acid itself, with little to no toxicity. However, other cellular components involved in the pathway were not affected. To the best of our knowledge, this is the first report on the inhibitory property of piperazic acid in this pathway. Hence, this molecule could serve as a useful tool for studying Hedgehog signaling. PMID:27528433

  14. Hydrogen Sulfide Is a Signaling Molecule and a Cytoprotectant

    PubMed Central

    Shibuya, Norihiro; Kimura, Yuka

    2012-01-01

    Abstract Significance: Accumulating evidence shows that hydrogen sulfide may function as a signaling molecule in processes such as neuromodulation in the brain and smooth muscle relaxation in the vascular system. It also has a cytoprotective effect, since it can protect neurons and cardiac muscle from oxidative stress and ischemia-reperfusion injury, respectively. Hydrogen sulfide can also modulate inflammation, insulin release, and angiogenesis. Recent Advances: The regulation of the activity of 3-mercaptopyruvate sulfur transferase (3MST) along with cysteine aminotransferase (CAT), one of the H2S producing pathways, has been demonstrated. The production of H2S by the pathway, which is regulated by Ca2+ and facilitated by thioredoxin and dihydrolipoic acid, is also involved in H2S signaling as well as cytoprotection. Sulfur hydration of proteins by H2S has been proposed to modulate protein functions. H2S-sensitive fluorescent probes, which enable us to measure the localization of H2S in real time, have been developed. Critical Issues: The basal concentrations of H2S have recently been measured and found to be much lower than those initially reported. However, the concentration of H2S reached in stimulated cells, as well as the regulation of H2S producing enzymes is not well understood. It has been proposed that some of the effects of H2S on the regulation of enzymes and receptors might be explained through the properties of sulfane sulfur (S0), another form of active sulfur. Future Directions: The determination of H2S concentrations in activated cells using new methods including H2S-sensitive fluorescent probes, as well as the investigation of the effects of H2S using specific inhibitors, may provide better understanding of the physiological function of this molecule. Clarifying mechanisms of H2S activity may also facilitate the development of new therapeutic compounds. Antioxid. Redox Signal. 17, 45–57. PMID:22229673

  15. Lysophosphatidic acid and signaling in sensory neurons.

    PubMed

    Oude Elferink, Ronald P J; Bolier, Ruth; Beuers, Ulrich H

    2015-01-01

    Lysophosphatidic acid is a potent signaling lipid molecule that has initially been characterized as a growth factor. However, later studies have revealed many more functions such as modulation of cell shape, cell migration, prevention of apoptosis, platelet aggregation, wound healing, osteoclast differentiation, vasopressor activity, embryo implantation, angiogenesis, lung fibrosis, hair growth and more. The molecule mainly acts through the activation of a set of at least 6 G-protein-coupled receptors (LPA1-6), but intracellular LPA was also shown to signal through the activation of the nuclear receptor PPARγ. In this short review we discuss the recent observations which suggest that in pathological conditions LPA also modulates signaling in sensory neurons. Thus, LPA has been shown to play a role in the initiation of neuropathic pain and, more recently, a relation was observed between increased LPA levels in the circulation and cholestatic itch. The mechanism by which this occurs remains to be elucidated. This article is part of a Special Issue entitled Linking transcription to physiology in lipodomics. PMID:25218302

  16. Carbon Monoxide as a Signaling Molecule in Plants.

    PubMed

    Wang, Meng; Liao, Weibiao

    2016-01-01

    Carbon monoxide (CO), a gaseous molecule, has emerged as a signaling molecule in plants, due to its ability to trigger a series of physiological reactions. This article provides a brief update on the synthesis of CO, its physiological functions in plant growth and development, as well as its roles in abiotic stress tolerance such as drought, salt, ultraviolet radiation, and heavy metal stress. CO has positive effects on seed germination, root development, and stomatal closure. Also, CO can enhance plant abiotic stress resistance commonly through the enhancement of antioxidant defense system. Moreover, CO shows cross talk with other signaling molecules including NO, phytohormones (IAA, ABA, and GA) and other gas signaling molecules (H2S, H2, CH4). PMID:27200045

  17. Carbon Monoxide as a Signaling Molecule in Plants

    PubMed Central

    Wang, Meng; Liao, Weibiao

    2016-01-01

    Carbon monoxide (CO), a gaseous molecule, has emerged as a signaling molecule in plants, due to its ability to trigger a series of physiological reactions. This article provides a brief update on the synthesis of CO, its physiological functions in plant growth and development, as well as its roles in abiotic stress tolerance such as drought, salt, ultraviolet radiation, and heavy metal stress. CO has positive effects on seed germination, root development, and stomatal closure. Also, CO can enhance plant abiotic stress resistance commonly through the enhancement of antioxidant defense system. Moreover, CO shows cross talk with other signaling molecules including NO, phytohormones (IAA, ABA, and GA) and other gas signaling molecules (H2S, H2, CH4). PMID:27200045

  18. Recent Advances in Developing Small Molecules Targeting Nucleic Acid

    PubMed Central

    Wang, Maolin; Yu, Yuanyuan; Liang, Chao; Lu, Aiping; Zhang, Ge

    2016-01-01

    Nucleic acids participate in a large number of biological processes. However, current approaches for small molecules targeting protein are incompatible with nucleic acids. On the other hand, the lack of crystallization of nucleic acid is the limiting factor for nucleic acid drug design. Because of the improvements in crystallization in recent years, a great many structures of nucleic acids have been reported, providing basic information for nucleic acid drug discovery. This review focuses on the discovery and development of small molecules targeting nucleic acids. PMID:27248995

  19. Docosahexaenoic acid in neural signaling systems.

    PubMed

    Crawford, Michael A

    2006-01-01

    Docosahexaenoic acid has been conserved in neural signalling systems in the cephalopods, fish, amphibian, reptiles, birds, mammals, primates and humans. This extreme conservation, despite wide genomic changes over 500 million years, testifies to a uniqueness of this molecule in the brain. The brain selectively incorporates docosahexaenoic acid and its rate of incorporation into the developing brain has been shown to be greater than ten times more efficient than its synthesis from the omega 3 fatty acids of land plant origin. Data has now been published demonstrating a significant influence of dietary omega 3 fatty acids on neural gene expression. As docosahexaenoic acid is the only omega 3 fatty acid in the brain, it is likely that it is the ligand involved. The selective uptake, requirement for function and stimulation of gene expression would have conferred an advantage to a primate which separated from the chimpanzees in the forests and woodlands and sought a different ecological niche. In view of the paucity of docosahexaenoic acid in the land food chain it is likely that the advantage would have been gained from a lacustrine or marine coastal habitat with access to food rich in docosahexaenoic acid and the accessory micronutrients, such as iodine, zinc, copper, manganese and selenium, of importance in brain development and protection against peroxidation. Land agricultural development has, in recent time, come to dominate the human food chain. The decline in use and availability of aquatic resources is not considered important by Langdon (2006) as he considers the resource was not needed for human evolution and can be replaced from the terrestrial food chain. This notion is not supported by the biochemistry nor the molecular biology. He misses the point that the shoreline hypothesis is not just dependent on docosahexaenoic acid but also on the other accessory nutrients specifically required by the brain. Moreover he neglects the basic principle of Darwinian

  20. Editorial of the Special Issue: Signaling Molecules and Signal Transduction in Cells

    PubMed Central

    Schlossmann, Jens

    2013-01-01

    In the special issue “Signaling Molecules and Signal Transduction in Cells” authors were invited to submit papers regarding important and novel aspects of extra- and intracellular signaling which have implications on physiological and pathophysiological processes. These aspects included compounds which are involved in these processes, elucidation of signaling pathways, as well as novel techniques for the analysis of signaling pathways. In response, various novel and important topics are elucidated in this special issue. PMID:23759992

  1. Unraveling plant hormone signaling through the use of small molecules

    PubMed Central

    Rigal, Adeline; Ma, Qian; Robert, Stéphanie

    2014-01-01

    Plants have acquired the capacity to grow continuously and adjust their morphology in response to endogenous and external signals, leading to a high architectural plasticity. The dynamic and differential distribution of phytohormones is an essential factor in these developmental changes. Phytohormone perception is a fast but complex process modulating specific developmental reprogramming. In recent years, chemical genomics or the use of small molecules to modulate target protein function has emerged as a powerful strategy to study complex biological processes in plants such as hormone signaling. Small molecules can be applied in a conditional, dose-dependent and reversible manner, with the advantage of circumventing the limitations of lethality and functional redundancy inherent to traditional mutant screens. High-throughput screening of diverse chemical libraries has led to the identification of bioactive molecules able to induce plant hormone-related phenotypes. Characterization of the cognate targets and pathways of those molecules has allowed the identification of novel regulatory components, providing new insights into the molecular mechanisms of plant hormone signaling. An extensive structure-activity relationship (SAR) analysis of the natural phytohormones, their designed synthetic analogs and newly identified bioactive molecules has led to the determination of the structural requirements essential for their bioactivity. In this review, we will summarize the so far identified small molecules and their structural variants targeting specific phytohormone signaling pathways. We will highlight how the SAR analyses have enabled better interrogation of the molecular mechanisms of phytohormone responses. Finally, we will discuss how labeled/tagged hormone analogs can be exploited, as compelling tools to better understand hormone signaling and transport mechanisms. PMID:25126092

  2. Multi-State Transition Kinetics of Intracellular Signaling Molecules by Single-Molecule Imaging Analysis.

    PubMed

    Matsuoka, Satomi; Miyanaga, Yukihiro; Ueda, Masahiro

    2016-01-01

    The chemotactic signaling of eukaryotic cells is based on a chain of interactions between signaling molecules diffusing on the cell membrane and those shuttling between the membrane and cytoplasm. In this chapter, we describe methods to quantify lateral diffusion and reaction kinetics on the cell membrane. By the direct visualization and statistic analyses of molecular Brownian movement achieved by single-molecule imaging techniques, multiple states of membrane-bound molecules are successfully revealed with state transition kinetics. Using PTEN, a phosphatidylinositol-3,4,5-trisphosphate (PI(3,4,5)P3) 3'-phosphatase, in Dictyostelium discoideum undergoing chemotaxis as a model, each process of the analysis is described in detail. The identified multiple state kinetics provides an essential clue to elucidating the molecular mechanism of chemoattractant-induced dynamic redistribution of the signaling molecule asymmetrically on the cell membrane. Quantitative parameters for molecular reactions and diffusion complement a conventional view of the chemotactic signaling system, where changing a static network of molecules connected by causal relationships into a spatiotemporally dynamic one permits a mathematical description of stochastic migration of the cell along a shallow chemoattractant gradient. PMID:27271914

  3. Agrobacterium tumefaciens responses to plant-derived signaling molecules

    PubMed Central

    Subramoni, Sujatha; Nathoo, Naeem; Klimov, Eugene; Yuan, Ze-Chun

    2014-01-01

    As a special phytopathogen, Agrobacterium tumefaciens infects a wide range of plant hosts and causes plant tumors also known as crown galls. The complexity of Agrobacterium–plant interaction has been studied for several decades. Agrobacterium pathogenicity is largely attributed to its evolved capabilities of precise recognition and response to plant-derived chemical signals. Agrobacterium perceives plant-derived signals to activate its virulence genes, which are responsible for transferring and integrating its Transferred DNA (T-DNA) from its Tumor-inducing (Ti) plasmid into the plant nucleus. The expression of T-DNA in plant hosts leads to the production of a large amount of indole-3-acetic acid (IAA), cytokinin (CK), and opines. IAA and CK stimulate plant growth, resulting in tumor formation. Agrobacterium utilizes opines as nutrient sources as well as signals in order to activate its quorum sensing (QS) to further promote virulence and opine metabolism. Intriguingly, Agrobacterium also recognizes plant-derived signals including γ-amino butyric acid and salicylic acid (SA) to activate quorum quenching that reduces the level of QS signals, thereby avoiding the elicitation of plant defense and preserving energy. In addition, Agrobacterium hijacks plant-derived signals including SA, IAA, and ethylene to down-regulate its virulence genes located on the Ti plasmid. Moreover, certain metabolites from corn (Zea mays) also inhibit the expression of Agrobacterium virulence genes. Here we outline the responses of Agrobacterium to major plant-derived signals that impact Agrobacterium–plant interactions. PMID:25071805

  4. Role of chrysin on expression of insulin signaling molecules

    PubMed Central

    Satyanarayana, Kottireddy; Sravanthi, Koora; Shaker, Ivvala Anand; Ponnulakshmi, Rajagopal; Selvaraj, Jayaraman

    2015-01-01

    Background: Currently available drugs are unsuccessful for the treatment of tye-2 diabetes due to their adverseside-effects. Hence, a search for novel drugs, especially ofplant origin, continues. Chrysin (5,7-dihydroxyflavone) is a flavonoid, natural component of traditional medicinal herbs, present in honey, propolis and many plant extracts that hasbeen used in traditional medicine around the world to treat numerous ailments. Objective: The present study was aimed to identify the protective role of chrysin on the expression of insulin-signaling molecules in the skeletal muscle of high fat and sucrose-induced type-2 diabetic adult male rats. Materials and Methods: The oral effective dose of chrysin (100 mg/kg body weight) was given once a day until the end of the study (30 days post-induction of diabetes) to high fat diet-induced diabetic rats. At the end of the experimental period, fasting blood glucose, oral glucose tolerance, serum lipid profile, lipid peroxidation (LPO) and free radical generation, as well as the levels of insulin signaling molecules and tissue glycogen in the gastrocnemius muscle were assessed. Results: Diabetic rats showed impaired glucose tolerance and impairment in insulin signaling molecules (IR, IRS-1, p-IRS-1Tyr632, p- AktThr308), glucose transporter subtype 4 [GLUT4] proteins and glycogen concentration. Serum insulin, lipid profile, LPO and free radical generation were found to be increased in diabetic control rats. The treatment with chrysin normalized the altered levels of blood glucose, serum insulin, lipid profile, LPO and insulin signaling molecules as well as GLUT4 proteins. Conclusion: Our present findings indicate that chrysin improves glycemic control through activation of insulin signal transduction in the gastrocnemius muscle of high fat and sucrose-induced type-2 diabetic male rats. PMID:26834424

  5. Tackling the bottleneck in bacterial signal transduction research: high-throughput identification of signal molecules.

    PubMed

    Krell, Tino

    2015-05-01

    Signal transduction processes are typically initiated by the interaction of signal molecules with sensor domains. The current lack of information on the signal molecules that feed into regulatory circuits forms a major bottleneck that hampers the understanding of regulatory processes. McKellar et al. report a high-throughput approach for the identification of signal molecules, which is based on thermal shift assays of recombinant sensor domains in the absence and presence of compounds from commercially available ligand collections. Initial binding studies with the sensor domain of the PctA chemoreceptor of Pseudomonas aeruginosa showed a close match between thermal shift assay results and microcalorimetric studies reported previously. Using thermal shift assays the authors then identify signals that bind to three chemoreceptors of the kiwifruit pathogen P. syringae pv. Actinidiae NZ-V13. Microcalorimetric binding studies and chemotaxis assays have validated the relevance of these ligands. The power of this technique lies in the combination of a high-throughput analytical tool with commercially available compound collections. The approach reported is universal since it can be employed to identify signal molecules to any type of sensor domain. There is no doubt that this technique will facilitate the identification of many signal molecules in future years. PMID:25708679

  6. Composition for detection of cell density signal molecule

    DOEpatents

    Schwarz, Richard I.

    2001-01-01

    Disclosed herein is a novel proteinaceous cell density signal molecule (CDS), which is secreted by fibroblastic cells in culture, preferably tendon cells, and which provides a means by which the cells self-regulate their proliferation and the expression of differentiated function. CDS, and the antibodies which recognize them, are important for the development of diagnostics and treatments for injuries and diseases involving connective tissues, particularly tendon. Also disclosed are methods of production and use.

  7. Gram-Negative Bacterial Sensors for Eukaryotic Signal Molecules

    PubMed Central

    Lesouhaitier, Olivier; Veron, Wilfried; Chapalain, Annelise; Madi, Amar; Blier, Anne-Sophie; Dagorn, Audrey; Connil, Nathalie; Chevalier, Sylvie; Orange, Nicole; Feuilloley, Marc

    2009-01-01

    Ample evidence exists showing that eukaryotic signal molecules synthesized and released by the host can activate the virulence of opportunistic pathogens. The sensitivity of prokaryotes to host signal molecules requires the presence of bacterial sensors. These prokaryotic sensors, or receptors, have a double function: stereospecific recognition in a complex environment and transduction of the message in order to initiate bacterial physiological modifications. As messengers are generally unable to freely cross the bacterial membrane, they require either the presence of sensors anchored in the membrane or transporters allowing direct recognition inside the bacterial cytoplasm. Since the discovery of quorum sensing, it was established that the production of virulence factors by bacteria is tightly growth-phase regulated. It is now obvious that expression of bacterial virulence is also controlled by detection of the eukaryotic messengers released in the micro-environment as endocrine or neuro-endocrine modulators. In the presence of host physiological stress many eukaryotic factors are released and detected by Gram-negative bacteria which in return rapidly adapt their physiology. For instance, Pseudomonas aeruginosa can bind elements of the host immune system such as interferon-γ and dynorphin and then through quorum sensing circuitry enhance its virulence. Escherichia coli sensitivity to the neurohormones of the catecholamines family appears relayed by a recently identified bacterial adrenergic receptor. In the present review, we will describe the mechanisms by which various eukaryotic signal molecules produced by host may activate Gram-negative bacteria virulence. Particular attention will be paid to Pseudomonas, a genus whose representative species, P. aeruginosa, is a common opportunistic pathogen. The discussion will be particularly focused on the pivotal role played by these new types of pathogen sensors from the sensing to the transduction mechanism involved in

  8. Observation of an electrical signal from a single molecule

    NASA Astrophysics Data System (ADS)

    Aslan, Arooj; Shaheen, Noor; Dobiszewski, Kyle; Kanwal, Alokik; Farrow, Reginald; Thomas, Gordon

    We have attached a folded protein molecule to the tip of a carbon nanotube using electrophoresis. We have then measured the electrons produced when the protein catalyzes a series of reactions. As an initial example of the reactions, we have used the catalysis by glucose-oxidase of glucose. We can show that the characteristic dynamic signals from the molecule scale with the glucose concentration. The molecule on the carbon nanotube tip is stable with respect to time under controlled conditions. The signals also indicate the glucose diffusion as its concentration is locally depleted at the nanotube by the catalysis. We use a second carbon nanotube with a laccase molecule on its tip to complete the circuit with an oxygen reaction. In a previous stage of this process, the other end of the nanotube is attached with a low-impedance electrical connection to a Ti thin film and the measuring circuitry. This work is an early step toward investigating the feasibility of an implantable glucose monitor to help treat diabetes.

  9. Decreased Gene Expressions of Insulin Signal Molecules in Canine Hyperadrenocorticism

    PubMed Central

    NOZAWA, Satoshi; ODA, Hitomi; AKIYAMA, Ran; UEDA, Kaori; SAEKI, Kaori; SHONO, Saori; MARUYAMA, Natsuki; MURATA, Atsuki; TAZAKI, Hiroyuki; MORI, Akihiro; MOMOTA, Yutaka; AZAKAMI, Daigo; SAKO, Toshinori; ISHIOKA, Katsumi

    2014-01-01

    ABSTRACT Hyperadrenocorticism (HAC) is a common endocrine disorder in dogs, in which excess glucocorticoid causes insulin resistance. Disturbance of insulin action may be caused by multiple factors, including transcriptional modulation of insulin signal molecules which lie downstream of insulin binding to insulin receptors. In this study, gene expressions of insulin signal molecules were examined using neutrophils of the HAC dogs (the untreated dogs and the dogs which had been treated with trilostane). Insulin receptor substrate (IRS)-1, IRS-2, phosphatidylinositol 3-kinase (PI3-K), protein kinase B/Akt kinase (Akt)-2 and protein kinase C (PKC)-lambda were analyzed in the HAC dogs and compared with those from normal dogs. The IRS-1 gene expressions decreased by 37% and 35% of the control dogs in the untreated and treated groups, respectively. The IRS-2 gene expressions decreased by 61% and 72%, the PI3-K gene expressions decreased by 47% and 55%, and the Akt-2 gene expressions decreased by 45% and 56% of the control dogs, similarly. Collectively, gene expressions of insulin signal molecules are suppressed in the HAC dogs, which may partially contribute to the induction of insulin resistance. PMID:24829079

  10. Isolated menthone reductase and nucleic acid molecules encoding same

    DOEpatents

    Croteau, Rodney B; Davis, Edward M; Ringer, Kerry L

    2013-04-23

    The present invention provides isolated menthone reductase proteins, isolated nucleic acid molecules encoding menthone reductase proteins, methods for expressing and isolating menthone reductase proteins, and transgenic plants expressing elevated levels of menthone reductase protein.

  11. Dissecting single-molecule signal transduction in carbon nanotube circuits with protein engineering

    PubMed Central

    Choi, Yongki; Olsen, Tivoli J.; Sims, Patrick C.; Moody, Issa S.; Corso, Brad L.; Dang, Mytrang N.; Weiss, Gregory A.; Collins, Philip G.

    2013-01-01

    Single molecule experimental methods have provided new insights into biomolecular function, dynamic disorder, and transient states that are all invisible to conventional measurements. A novel, non-fluorescent single molecule technique involves attaching single molecules to single-walled carbon nanotube field-effective transistors (SWNT FETs). These ultrasensitive electronic devices provide long-duration, label-free monitoring of biomolecules and their dynamic motions. However, generalization of the SWNT FET technique first requires design rules that can predict the success and applicability of these devices. Here, we report on the transduction mechanism linking enzymatic processivity to electrical signal generation by a SWNT FET. The interaction between SWNT FETs and the enzyme lysozyme was systematically dissected using eight different lysozyme variants synthesized by protein engineering. The data prove that effective signal generation can be accomplished using a single charged amino acid, when appropriately located, providing a foundation to widely apply SWNT FET sensitivity to other biomolecular systems. PMID:23323846

  12. Intermediates of Metabolism: From Bystanders to Signalling Molecules.

    PubMed

    Haas, Robert; Cucchi, Danilo; Smith, Joanne; Pucino, Valentina; Macdougall, Claire Elizabeth; Mauro, Claudio

    2016-05-01

    The integration of biochemistry into immune cell biology has contributed immensely to our understanding of immune cell function and the associated pathologies. So far, most studies have focused on the regulation of metabolic pathways during an immune response and their contribution to its success. More recently, novel signalling functions of metabolic intermediates are being discovered that might play important roles in the regulation of immunity. Here we describe the three long-known small metabolites lactate, acetyl-CoA, and succinate in the context of immunometabolic signalling. Functions of these ubiquitous molecules are largely dependent on their intra- and extracellular concentrations as well as their subcompartmental localisation. Importantly, the signalling functions of these metabolic intermediates extend beyond self-regulatory roles and include cell-to-cell communication and sensing of microenvironmental conditions to elicit stress responses and cellular adaptation. PMID:26935843

  13. Hydrogen peroxide and nitric oxide as signalling molecules in plants.

    PubMed

    Neill, Steven J; Desikan, Radhika; Clarke, Andrew; Hurst, Roger D; Hancock, John T

    2002-05-01

    It is now clear that hydrogen peroxide (H(2)O(2)) and nitric oxide (NO) function as signalling molecules in plants. A wide range of abiotic and biotic stresses results in H(2)O(2) generation, from a variety of sources. H(2)O(2) is removed from cells via a number of antioxidant mechanisms, both enzymatic and non-enzymatic. Both biotic and abiotic stresses can induce NO synthesis, but the biosynthetic origins of NO in plants have not yet been resolved. Cellular responses to H(2)O(2) and NO are complex, with considerable cross-talk between responses to several stimuli. In this review the potential roles of H(2)O(2) and NO during various stresses and the signalling pathways they activate are discussed. Key signalling components that might provide targets for enhancing crop production are also identified. PMID:11997372

  14. Targeting signaling pathways with small molecules to treat autoimmune disorders.

    PubMed

    Kaminska, Bozena; Swiatek-Machado, Karolina

    2008-01-01

    Chronic activation of immune responses, mediated by inflammatory mediators and involving different effector cells of the innate and acquired immune system characterizes autoimmune disorders, such as rheumatoid arthritis, inflammatory bowel disease, psoriasis and septic shock syndrome. MAPKs are crucial intracellular mediators of inflammation. MAPK inhibitors are attractive anti-inflammatory drugs, because they are capable of reducing the synthesis of inflammation mediators at multiple levels and are effective in blocking proinflammatory cytokine signaling. Janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway converts cytokine signals into genomic responses regulating proliferation and differentiation of the immune cells. JAK inhibitors are a new class of immunomodulatory agents with immunosuppressive, anti-inflammatory and antiallergic properties. This review discusses the rationale behind current strategies of targeting MAPK and JAK/STAT signaling pathways, and the overall effects of signal transduction inhibitors in animal models of inflammatory disorders. Signal transduction inhibitors are small molecules that can be administered orally, and initial results of clinical trials have shown clinical benefits in patients with chronic inflammatory disorders. PMID:20477590

  15. Nutritional Signaling via Free Fatty Acid Receptors.

    PubMed

    Miyamoto, Junki; Hasegawa, Sae; Kasubuchi, Mayu; Ichimura, Atsuhiko; Nakajima, Akira; Kimura, Ikuo

    2016-01-01

    Excess energy is stored primarily as triglycerides, which are mobilized when demand for energy arises. Dysfunction of energy balance by excess food intake leads to metabolic diseases, such as obesity and diabetes. Free fatty acids (FFAs) provided by dietary fat are not only important nutrients, but also contribute key physiological functions via FFA receptor (FFAR)-mediated signaling molecules, which depend on FFAs' carbon chain length and the ligand specificity of the receptors. Functional analyses have revealed that FFARs are critical for metabolic functions, such as peptide hormone secretion and inflammation, and contribute to energy homeostasis. In particular, recent studies have shown that the administration of selective agonists of G protein-coupled receptor (GPR) 40 and GPR120 improved glucose metabolism and systemic metabolic disorders. Furthermore, the anti-inflammation and energy metabolism effects of short chain FAs have been linked to the activation of GPR41 and GPR43. In this review, we summarize recent progress in research on FFAs and their physiological roles in the regulation of energy metabolism. PMID:27023530

  16. Nutritional Signaling via Free Fatty Acid Receptors

    PubMed Central

    Miyamoto, Junki; Hasegawa, Sae; Kasubuchi, Mayu; Ichimura, Atsuhiko; Nakajima, Akira; Kimura, Ikuo

    2016-01-01

    Excess energy is stored primarily as triglycerides, which are mobilized when demand for energy arises. Dysfunction of energy balance by excess food intake leads to metabolic diseases, such as obesity and diabetes. Free fatty acids (FFAs) provided by dietary fat are not only important nutrients, but also contribute key physiological functions via FFA receptor (FFAR)-mediated signaling molecules, which depend on FFAs’ carbon chain length and the ligand specificity of the receptors. Functional analyses have revealed that FFARs are critical for metabolic functions, such as peptide hormone secretion and inflammation, and contribute to energy homeostasis. In particular, recent studies have shown that the administration of selective agonists of G protein-coupled receptor (GPR) 40 and GPR120 improved glucose metabolism and systemic metabolic disorders. Furthermore, the anti-inflammation and energy metabolism effects of short chain FAs have been linked to the activation of GPR41 and GPR43. In this review, we summarize recent progress in research on FFAs and their physiological roles in the regulation of energy metabolism. PMID:27023530

  17. Bile acid signaling and biliary functions

    PubMed Central

    Jones, Hannah; Alpini, Gianfranco; Francis, Heather

    2015-01-01

    This review focuses on various components of bile acid signaling in relation to cholangiocytes. Their roles as targets for potential therapies for cholangiopathies are also explored. While many factors are involved in these complex signaling pathways, this review emphasizes the roles of transmembrane G protein coupled receptor (TGR5), farnesoid X receptor (FXR), ursodeoxycholic acid (UDCA) and the bicarbonate umbrella. Following a general background on cholangiocytes and bile acids, we will expand the review and include sections that are most recently known (within 5–7 years) regarding the field of bile acid signaling and cholangiocyte function. These findings all demonstrate that bile acids influence biliary functions which can, in turn, regulate the cholangiocyte response during pathological events. PMID:26579437

  18. Bile acid metabolism and signaling in cholestasis, inflammation and cancer

    PubMed Central

    Apte, Udayan

    2015-01-01

    Bile acids are synthesized from cholesterol in the liver. Some cytochrome P450 (CYP) enzymes play key roles in bile acid synthesis. Bile acids are physiological detergent molecules, so are highly cytotoxic. They undergo enterohepatic circulation and play important roles in generating bile flow and facilitating biliary secretion of endogenous metabolites and xenobiotics and intestinal absorption of dietary fats and lipid soluble vitamins. Bile acid synthesis, transport and pool size are therefore tightly regulated under physiological conditions. In cholestasis, impaired bile flow leads to accumulation of bile acids in the liver, causing hepatocyte and biliary injury and inflammation. Chronic cholestasis is associated with fibrosis, cirrhosis and eventually liver failure. Chronic cholestasis also increases the risk of developing hepatocellular or cholangiocellular carcinomas. Extensive research in the last two decades has shown that bile acids act as signaling molecules that regulate various cellular processes. The bile acid-activated nuclear receptors are ligand-activated transcriptional factors that play critical roles in the regulation of bile acid, drug and xenobiotic metabolism. In cholestasis, these bile acid-activated receptors regulate a network of genes involved in bile acid synthesis, conjugation, transport and metabolism to alleviate bile acid-induced inflammation and injury. Additionally, bile acids are known to regulate cell growth and proliferation, and altered bile acid levels in diseased conditions have been implicated in liver injury/regeneration and tumorigenesis. We will cover the mechanisms that regulate bile acid homeostasis and detoxification during cholestasis, and the roles of bile acids in the initiation and regulation of hepatic inflammation, regeneration and carcinogenesis. PMID:26233910

  19. Methods And Devices For Characterizing Duplex Nucleic Acid Molecules

    DOEpatents

    Akeson, Mark; Vercoutere, Wenonah; Haussler, David; Winters-Hilt, Stephen

    2005-08-30

    Methods and devices are provided for characterizing a duplex nucleic acid, e.g., a duplex DNA molecule. In the subject methods, a fluid conducting medium that includes a duplex nucleic acid molecule is contacted with a nanopore under the influence of an applied electric field and the resulting changes in current through the nanopore caused by the duplex nucleic acid molecule are monitored. The observed changes in current through the nanopore are then employed as a set of data values to characterize the duplex nucleic acid, where the set of data values may be employed in raw form or manipulated, e.g., into a current blockade profile. Also provided are nanopore devices for practicing the subject methods, where the subject nanopore devices are characterized by the presence of an algorithm which directs a processing means to employ monitored changes in current through a nanopore to characterize a duplex nucleic acid molecule responsible for the current changes. The subject methods and devices find use in a variety of applications, including, among other applications, the identification of an analyte duplex DNA molecule in a sample, the specific base sequence at a single nulceotide polymorphism (SNP), and the sequencing of duplex DNA molecules.

  20. Progress in Small Molecule and Biologic Therapeutics Targeting Ghrelin Signaling.

    PubMed

    McGovern, Kayleigh R; Darling, Joseph E; Hougland, James L

    2016-01-01

    Ghrelin is a circulating peptide hormone involved in regulation of a wide array of physiological processes. As an endogenous ligand for growth hormone secretagogue receptor (GHSR1a), ghrelin is responsible for signaling involved in energy homeostasis, including appetite stimulation, glucose metabolism, insulin signaling, and adiposity. Ghrelin has also been implicated in modulation of several neurological processes. Dysregulation of ghrelin signaling is implicated in diseases related to these pathways, including obesity, type II diabetes, and regulation of appetite and body weight in patients with Prader-Willi syndrome. Multiple steps in the ghrelin signaling pathway are available for targeting in the development of therapeutics for these diseases. Agonists and antagonists of GHS-R1a have been widely studied and have shown varying levels of effectiveness within ghrelin-related physiological pathways. Agents targeting ghrelin directly, either through depletion of ghrelin levels in circulation or inhibitors of ghrelin O-acyltransferase whose action is required for ghrelin to become biologically active, are receiving increasing attention as potential therapeutic options. We discuss the approaches utilized to target ghrelin signaling and highlight the current challenges toward developing small-molecule agents as potential therapeutics for ghrelin-related diseases. PMID:26202202

  1. TRAF molecules in cell signaling and in human diseases

    PubMed Central

    2013-01-01

    The tumor necrosis factor receptor (TNF-R)-associated factor (TRAF) family of intracellular proteins were originally identified as signaling adaptors that bind directly to the cytoplasmic regions of receptors of the TNF-R superfamily. The past decade has witnessed rapid expansion of receptor families identified to employ TRAFs for signaling. These include Toll-like receptors (TLRs), NOD-like receptors (NLRs), RIG-I-like receptors (RLRs), T cell receptor, IL-1 receptor family, IL-17 receptors, IFN receptors and TGFβ receptors. In addition to their role as adaptor proteins, most TRAFs also act as E3 ubiquitin ligases to activate downstream signaling events. TRAF-dependent signaling pathways typically lead to the activation of nuclear factor-κBs (NF-κBs), mitogen-activated protein kinases (MAPKs), or interferon-regulatory factors (IRFs). Compelling evidence obtained from germ-line and cell-specific TRAF-deficient mice demonstrates that each TRAF plays indispensable and non-redundant physiological roles, regulating innate and adaptive immunity, embryonic development, tissue homeostasis, stress response, and bone metabolism. Notably, mounting evidence implicates TRAFs in the pathogenesis of human diseases such as cancers and autoimmune diseases, which has sparked new appreciation and interest in TRAF research. This review presents an overview of the current knowledge of TRAFs, with an emphasis on recent findings concerning TRAF molecules in signaling and in human diseases. PMID:23758787

  2. Wnt/beta-Catenin Signaling and Small Molecule Inhibitors

    PubMed Central

    Voronkov, Andrey; Krauss, Stefan

    2012-01-01

    Wnt/β-catenin signaling is a branch of a functional network that dates back to the first metazoans and it is involved in a broad range of biological systems including stem cells, embryonic development and adult organs. Deregulation of components involved in Wnt/β-catenin signaling has been implicated in a wide spectrum of diseases including a number of cancers and degenerative diseases. The key mediator of Wnt signaling, β-catenin, serves several cellular functions. It functions in a dynamic mode at multiple cellular locations, including the plasma membrane, where β-catenin contributes to the stabilization of intercellular adhesive complexes, the cytoplasm where β-catenin levels are regulated and the nucleus where β-catenin is involved in transcriptional regulation and chromatin interactions. Central effectors of β-catenin levels are a family of cysteine-rich secreted glycoproteins, known as Wnt morphogens. Through the LRP5/6-Frizzled receptor complex, Wnts regulate the location and activity of the destruction complex and consequently intracellular β- catenin levels. However, β-catenin levels and their effects on transcriptional programs are also influenced by multiple other factors including hypoxia, inflammation, hepatocyte growth factor-mediated signaling, and the cell adhesion molecule E-cadherin. The broad implications of Wnt/β-catenin signaling in development, in the adult body and in disease render the pathway a prime target for pharmacological research and development. The intricate regulation of β-catenin at its various locations provides alternative points for therapeutic interventions. PMID:23016862

  3. Glycation Reactivity of a Quorum-Sensing Signaling Molecule.

    PubMed

    Tsuchikama, Kyoji; Gooyit, Major; Harris, Tyler L; Zhu, Jie; Globisch, Daniel; Kaufmann, Gunnar F; Janda, Kim D

    2016-03-14

    Reported herein is that (4S)-4,5-dihydroxy-2,3-pentanedione (DPD) can undergo a previously undocumented non-enzymatic glycation reaction. Incubation of DPD with viral DNA or the antibiotic gramicidin S resulted in significant biochemical alterations. A protein-labeling method was consequently developed that facilitated the identification of unrecognized glycation targets of DPD in a prokaryotic system. These results open new avenues toward tracking and understanding the fate and function of the elusive quorum-sensing signaling molecule. PMID:26890076

  4. Signal Transduction Molecules as Targets for Cancer Prevention

    PubMed Central

    Bode, Ann M.; Dong, Zigang

    2010-01-01

    Environmental and life-style aspects are major contributors to human carcinogenesis and, therefore, many human cancers may be preventable. Cancer is the end result of defects in cellular signaling processes that play a key role in the control of cell growth, survival, division, and differentiation. Therefore, identifying molecular and cellular targets critical in cancer development and prevention is an area of intensive research, driving the development of highly specific small-molecule inhibitors. A major idea today is that cancer may be prevented or treated by targeting the products of specific cancer-related genes, frequently encoding signaling proteins or transcription factors. Participants in these joint conferences discussed their latest findings in the identification of promising molecular targets and the development of agents directed against these targets with the goal of effectively transitioning these into the clinical setting. PMID:19244209

  5. Aging. Lysosomal signaling molecules regulate longevity in Caenorhabditis elegans.

    PubMed

    Folick, Andrew; Oakley, Holly D; Yu, Yong; Armstrong, Eric H; Kumari, Manju; Sanor, Lucas; Moore, David D; Ortlund, Eric A; Zechner, Rudolf; Wang, Meng C

    2015-01-01

    Lysosomes are crucial cellular organelles for human health that function in digestion and recycling of extracellular and intracellular macromolecules. We describe a signaling role for lysosomes that affects aging. In the worm Caenorhabditis elegans, the lysosomal acid lipase LIPL-4 triggered nuclear translocalization of a lysosomal lipid chaperone LBP-8, which promoted longevity by activating the nuclear hormone receptors NHR-49 and NHR-80. We used high-throughput metabolomic analysis to identify several lipids in which abundance was increased in worms constitutively overexpressing LIPL-4. Among them, oleoylethanolamide directly bound to LBP-8 and NHR-80 proteins, activated transcription of target genes of NHR-49 and NHR-80, and promoted longevity in C. elegans. These findings reveal a lysosome-to-nucleus signaling pathway that promotes longevity and suggest a function of lysosomes as signaling organelles in metazoans. PMID:25554789

  6. Abscisic acid signaling through cyclic ADP-ribose in plants

    SciTech Connect

    Wu, Yan; Kuzma, J.; Marechal, E.

    1997-12-19

    Abscisic acid (ABA) is the primary hormone that mediates plant responses to stresses such as cold, drought, and salinity. Single-cell microinjection experiments in tomato were used to identify possible intermediates involved in ABA signal transduction. Cyclic ADP-ribose (cADPR) was identified as a signaling molecule in the ABA response and was shown to exert its effects by way of calcium. Bioassay experiments showed that the amounts of cADPR in Arabidopsis thaliana plants increased in response to ABA treatment and before ABA-induced gene expression.

  7. Cross-talk in abscisic acid signaling

    NASA Technical Reports Server (NTRS)

    Fedoroff, Nina V.

    2002-01-01

    "Cross-talk" in hormone signaling reflects an organism's ability to integrate different inputs and respond appropriately, a crucial function at the heart of signaling network operation. Abscisic acid (ABA) is a plant hormone involved in bud and seed dormancy, growth regulation, leaf senescence and abscission, stomatal opening, and a variety of plant stress responses. This review summarizes what is known about ABA signaling in the control of stomatal opening and seed dormancy and provides an overview of emerging knowledge about connections between ABA, ethylene, sugar, and auxin synthesis and signaling.

  8. Phase separation of signaling molecules promotes T cell receptor signal transduction.

    PubMed

    Su, Xiaolei; Ditlev, Jonathon A; Hui, Enfu; Xing, Wenmin; Banjade, Sudeep; Okrut, Julia; King, David S; Taunton, Jack; Rosen, Michael K; Vale, Ronald D

    2016-04-29

    Activation of various cell surface receptors triggers the reorganization of downstream signaling molecules into micrometer- or submicrometer-sized clusters. However, the functional consequences of such clustering have been unclear. We biochemically reconstituted a 12-component signaling pathway on model membranes, beginning with T cell receptor (TCR) activation and ending with actin assembly. When TCR phosphorylation was triggered, downstream signaling proteins spontaneously separated into liquid-like clusters that promoted signaling outputs both in vitro and in human Jurkat T cells. Reconstituted clusters were enriched in kinases but excluded phosphatases and enhanced actin filament assembly by recruiting and organizing actin regulators. These results demonstrate that protein phase separation can create a distinct physical and biochemical compartment that facilitates signaling. PMID:27056844

  9. Bile acids are nutrient signaling hormones.

    PubMed

    Zhou, Huiping; Hylemon, Phillip B

    2014-08-01

    Bile salts play crucial roles in allowing the gastrointestinal system to digest, transport and metabolize nutrients. They function as nutrient signaling hormones by activating specific nuclear receptors (FXR, PXR, Vitamin D) and G-protein coupled receptors [TGR5, sphingosine-1 phosphate receptor 2 (S1PR2), muscarinic receptors]. Bile acids and insulin appear to collaborate in regulating the metabolism of nutrients in the liver. They both activate the AKT and ERK1/2 signaling pathways. Bile acid induction of the FXR-α target gene, small heterodimer partner (SHP), is highly dependent on the activation PKCζ, a branch of the insulin signaling pathway. SHP is an important regulator of glucose and lipid metabolism in the liver. One might hypothesize that chronic low grade inflammation which is associated with insulin resistance, may inhibit bile acid signaling and disrupt lipid metabolism. The disruption of these signaling pathways may increase the risk of fatty liver and non-alcoholic fatty liver disease (NAFLD). Finally, conjugated bile acids appear to promote cholangiocarcinoma growth via the activation of S1PR2. PMID:24819989

  10. Bile Acid Signaling in Metabolic Disease and Drug Therapy

    PubMed Central

    Li, Tiangang

    2014-01-01

    Bile acids are the end products of cholesterol catabolism. Hepatic bile acid synthesis accounts for a major fraction of daily cholesterol turnover in humans. Biliary secretion of bile acids generates bile flow and facilitates hepatobiliary secretion of lipids, lipophilic metabolites, and xenobiotics. In the intestine, bile acids are essential for the absorption, transport, and metabolism of dietary fats and lipid-soluble vitamins. Extensive research in the last 2 decades has unveiled new functions of bile acids as signaling molecules and metabolic integrators. The bile acid–activated nuclear receptors farnesoid X receptor, pregnane X receptor, constitutive androstane receptor, vitamin D receptor, and G protein–coupled bile acid receptor play critical roles in the regulation of lipid, glucose, and energy metabolism, inflammation, and drug metabolism and detoxification. Bile acid synthesis exhibits a strong diurnal rhythm, which is entrained by fasting and refeeding as well as nutrient status and plays an important role for maintaining metabolic homeostasis. Recent research revealed an interaction of liver bile acids and gut microbiota in the regulation of liver metabolism. Circadian disturbance and altered gut microbiota contribute to the pathogenesis of liver diseases, inflammatory bowel diseases, nonalcoholic fatty liver disease, diabetes, and obesity. Bile acids and their derivatives are potential therapeutic agents for treating metabolic diseases of the liver. PMID:25073467

  11. Integrating Retinoic Acid Signaling with Brain Function

    ERIC Educational Resources Information Center

    Luo, Tuanlian; Wagner, Elisabeth; Drager, Ursula C.

    2009-01-01

    The vitamin A derivative retinoic acid (RA) regulates the transcription of about a 6th of the human genome. Compelling evidence indicates a role of RA in cognitive activities, but its integration with the molecular mechanisms of higher brain functions is not known. Here we describe the properties of RA signaling in the mouse, which point to…

  12. Nuclear bile acid signaling through the farnesoid X receptor.

    PubMed

    Mazuy, Claire; Helleboid, Audrey; Staels, Bart; Lefebvre, Philippe

    2015-05-01

    Bile acids (BAs) are amphipathic molecules produced from cholesterol by the liver. Expelled from the gallbladder upon meal ingestion, BAs serve as fat solubilizers in the intestine. BAs are reabsorbed in the ileum and return via the portal vein to the liver where, together with nutrients, they provide signals to coordinate metabolic responses. BAs act on energy and metabolic homeostasis through the activation of membrane and nuclear receptors, among which the nuclear receptor farnesoid X receptor (FXR) is an important regulator of several metabolic pathways. Highly expressed in the liver and the small intestine, FXR contributes to BA effects on metabolism, inflammation and cell cycle control. The pharmacological modulation of its activity has emerged as a potential therapeutic strategy for liver and metabolic diseases. This review highlights recent advances regarding the mechanisms by which the BA sensor FXR contributes to global signaling effects of BAs, and how FXR activity may be regulated by nutrient-sensitive signaling pathways. PMID:25511198

  13. Lysophosphatidic Acid (LPA) Signaling in Vertebrate Reproduction

    PubMed Central

    Ye, Xiaoqin; Chun, Jerold

    2009-01-01

    Lysophosphatidic acid (LPA) is a cell membrane phospholipid metabolite that can act as an extracellular signal. Its effects are mediated through at least five G protein-coupled receptors (GPCRs), LPA1-5, and likely others as well. Studies in multiple species including LPA receptor-deficient mice and humans have identified or implicated important roles for receptor-mediated LPA signaling in multiple aspects of vertebrate reproduction. These include ovarian function, spermatogenesis, fertilization, early embryo development, embryo implantation, embryo spacing, decidualization, pregnancy maintenance, and parturition. LPA signaling may also have pathological consequences, influencing aspects of endometriosis and ovarian cancer. Here we review recent progress in LPA signaling research relevant to female and male reproduction. PMID:19836970

  14. Rag GTPase in amino acid signaling.

    PubMed

    Kim, Joungmok; Kim, Eunjung

    2016-04-01

    Rag small GTPases were identified as the sixth subfamily of Ras-related GTPases. Compelling evidence suggests that Rag heterodimer (RagA/B and RagC/D) plays an important role in amino acid signaling toward mechanistic target of rapamycin complex 1 (mTORC1), which is a central player in the control of cell growth in response to a variety of environmental cues, including growth factors, cellular energy/oxygen status, and amino acids. Upon amino acid stimulation, active Rag heterodimer (RagA/B(GTP)-RagC/D(GDP)) recruits mTORC1 to the lysosomal membrane where Rheb resides. In this review, we provide a current understanding on the amino acid-regulated cell growth control via Rag-mTORC1 with recently identified key players, including Ragulator, v-ATPase, and GATOR complexes. Moreover, the functions of Rag in physiological systems and in autophagy are discussed. PMID:26781224

  15. Evolution of retinoic acid receptors and retinoic acid signaling.

    PubMed

    Gutierrez-Mazariegos, Juliana; Schubert, Michael; Laudet, Vincent

    2014-01-01

    Retinoic acid (RA) is a vitamin A-derived morphogen controlling important developmental processes in vertebrates, and more generally in chordates, including axial patterning and tissue formation and differentiation. In the embryo, endogenous RA levels are controlled by RA synthesizing and degrading enzymes and the RA signal is transduced by two retinoid receptors: the retinoic acid receptor (RAR) and the retinoid X receptor (RXR). Both RAR and RXR are members of the nuclear receptor superfamily of ligand-activated transcription factors and mainly act as heterodimers to activate the transcription of target genes in the presence of their ligand, all-trans RA. This signaling pathway was long thought to be a chordate innovation, however, recent findings of gene homologs involved in RA signaling in the genomes of a wide variety of non-chordate animals, including ambulacrarians (sea urchins and acorn worms) and lophotrochozoans (annelids and mollusks), challenged this traditional view and suggested that the RA signaling pathway might have a more ancient evolutionary origin than previously thought. In this chapter, we discuss the evolutionary history of the RA signaling pathway, and more particularly of the RARs, which might have experienced independent gene losses and duplications in different animal lineages. In sum, the available data reveal novel insights into the origin of the RA signaling pathway as well as into the evolutionary history of the RARs. PMID:24962881

  16. Cotton Rat (Sigmodon hispidus) Signaling Lymphocyte Activation Molecule (CD150) Is an Entry Receptor for Measles Virus

    PubMed Central

    Carsillo, Thomas; Huey, Devra; Levinsky, Amy; Obojes, Karola; Schneider-Schaulies, Jürgen; Niewiesk, Stefan

    2014-01-01

    Cotton rats (Sigmodon hispidus) replicate measles virus (MV) after intranasal infection in the respiratory tract and lymphoid tissue. We have cloned the cotton rat signaling lymphocytic activation molecule (CD150, SLAM) in order to investigate its role as a potential receptor for MV. Cotton rat CD150 displays 58% and 78% amino acid homology with human and mouse CD150, respectively. By staining with a newly generated cotton rat CD150 specific monoclonal antibody expression of CD150 was confirmed in cotton rat lymphoid cells and in tissues with a pattern of expression similar to mouse and humans. Previously, binding of MV hemagglutinin has been shown to be dependent on amino acids 60, 61 and 63 in the V region of CD150. The human molecule contains isoleucine, histidine and valine at these positions and binds to MV-H whereas the mouse molecule contains valine, arginine and leucine and does not function as a receptor for MV. In the cotton rat molecule, amino acids 61 and 63 are identical with the mouse molecule and amino acid 60 with the human molecule. After transfection with cotton rat CD150 HEK 293 T cells became susceptible to infection with single cycle VSV pseudotype virus expressing wild type MV glycoproteins and with a MV wildtype virus. After infection, cells expressing cotton rat CD150 replicated virus to lower levels than cells expressing the human molecule and formed smaller plaques. These data might explain why the cotton rat is a semipermissive model for measles virus infection. PMID:25295727

  17. History of gymnemic acid, a molecule that does not exist. .

    PubMed

    Zarrelli, Armando; Romanucci, Valeria; Gravante, Raffaele; Di Marino, Cinzia; Di Fabio, Giovanni

    2014-10-01

    In the literature there are hundreds of articles, the first dating back to 1866 and the last to 2014, on gymnemic acid, isolated from Gymnnema sylvestre, from its isolation to the determination of its biological activities. Gymnemic acid has a CAS number but its structure is not specified. Studies during the second half of the 1970s clearly demonstrated that what was being referred to as gymnemic acid is actually a very complex mixture of dozens of substances, belonging to different classes of natural compounds. This plant, whose infusions or complex mixtures of its metabolites are the basis for many formulas sold in pharmacies and by herbalists, has anti-diabetic and slimming effects. It is certainly misleading to talk about gymnemic acid as a specific molecule. There may be doubts about the exact composition of the products, and consequently about their origin and the claimed effects. PMID:25522530

  18. Sugar amino acids and their uses in designing bioactive molecules.

    PubMed

    Chakraborty, Tushar K; Ghosh, Subhash; Jayaprakash, Sarva

    2002-02-01

    In search of new molecular entities for discovering new drugs and materials, organic chemists are looking for innovative approaches that try to imitate nature in assembling quickly large number of distinct and diverse molecular structures from 'nature-like' and yet unnatural designer building blocks using combinatorial approach. The main objective in developing such libraries is to mimic the diversities displayed in structures and properties of natural products. The unnatural building blocks used in these assemblies are carefully designed to manifest the structural diversities of the monomeric units used by nature like amino acids, carbohydrates and nucleosides to build its arsenal. Compounds made of such unnatural building blocks are also expected to be more stable toward proteolytic cleavage in physiological systems than their natural counterparts. Sugar amino acids constitute an important class of such polyfunctional scaffolds where the carboxyl, amino and hydroxyl termini provide an excellent opportunity to organic chemists to create structural diversities akin to nature's molecular arsenal. Recent advances in the area of combinatorial chemistry give an unprecedented technological support for rapid compilations of sugar amino acid-based libraries exploiting the diversities of carbohydrate molecules and well-developed solid-phase peptide synthesis methods. This review describes the development of sugar amino acids as a novel class of peptidomimetic building blocks and their applications in creating large number of structurally diverse peptide-based molecules many of which display interesting three-dimensional structures as well as useful biological properties. PMID:11945118

  19. Visual Map Development: Bidirectional Signaling, Bifunctional Guidance Molecules, and Competition

    PubMed Central

    Feldheim, David A.; O’Leary, Dennis D. M.

    2010-01-01

    Topographic maps are a two-dimensional representation of one neural structure within another and serve as the main strategy to organize sensory information. The retina’s projection via axons of retinal ganglion cells to midbrain visual centers, the optic tectum/superior colliculus, is the leading model to elucidate mechanisms of topographic map formation. Each axis of the retina is mapped independently using different mechanisms and sets of axon guidance molecules expressed in gradients to achieve the goal of representing a point in the retina onto a point within the target. An axon’s termination along the temporal-nasal mapping axis is determined by opposing gradients of EphAs and ephrin-As that act through their forward and reverse signaling, respectively, within the projecting axons, each of which inhibits interstitial branching, cooperating with a branch-promoting activity, to generate topographic specific branching along the shaft of the parent axons that overshoot their correct termination zone along the anterior-posterior axis of the target. The dorsal-ventral termination position is then determined using a gradient of ephrin-B that can act as a repellent or attractant depending on the ephrin-B concentration relative to EphB levels on the interstitial branches to guide them along the medial-lateral axis of the target to their correct termination zone, where they arborize. In both cases, axon-axon competition results in axon mapping based on relative rather than absolute levels of repellent or attractant activity. The map is subsequently refined through large-scale pruning driven in large part by patterned retinal activity. PMID:20880989

  20. Signal transduction molecules in gliomas of all grades

    PubMed Central

    Ermoian, Ralph P.; Kaprealian, Tania; Lamborn, Kathleen R.; Yang, Xiaodong; Jelluma, Nannette; Arvold, Nils D.; Zeidman, Ruth; Berger, Mitchel S.; Stokoe, David

    2010-01-01

    Purpose To interrogate grade II, III, and IV gliomas and characterize the critical effectors within the PI3-kinase pathway upstream and downstream of mTOR. Experimental design Tissues from 87 patients who were treated at UCSF between 1990 and 2004 were analyzed. Twenty-eight grade II, 17 grade III glioma, 26 grade IV gliomas, and 16 non-tumor brain specimens were analyzed. Protein levels were assessed by immunoblots; RNA levels were determined by polymerase chain reaction amplification. To address the multiple comparisons, first an overall analysis was done comparing the four groups using Spearman’s Correlation Coefficient. Only if this analysis was statistically significant were individual pairwise comparisons done. Results Multiple comparison analyses revealed a significant correlation with grade for all variables examined, except phosphorylated-S6. Expression of phosphorylated-4E-BP1, phosphorylated-PKB/Akt, PTEN, TSC1, and TSC2 correlated with grade (P < 0.01 for all). We extended our analyses to ask whether decreases in TSC proteins levels were due to changes in mRNA levels, or due to changes in post-transcriptional alterations. We found significantly lower levels of TSC1 and TSC2 mRNA in GBMs than in grade II gliomas or non-tumor brain (P < 0.01). Conclusions Expression levels of critical signaling molecules upstream and downstream of mTOR differ between non-tumor brain and gliomas of any grade. The single variable whose expression did not differ between non-tumor brain and gliomas was phosphorylated-S6, suggesting that other protein kinases, in addition to mTOR, contribute significantly to S6 phosphorylation. mTOR provides a rational therapeutic target in gliomas of all grades, and clinical benefit may emerge as mTOR inhibitors are combined with additional agents. PMID:18759130

  1. Biotic inactivation of the Pseudomonas aeruginosa quinolone signal molecule.

    PubMed

    Soh, Eliza Ye-Chen; Chhabra, Siri R; Halliday, Nigel; Heeb, Stephan; Müller, Christine; Birmes, Franziska S; Fetzner, Susanne; Cámara, Miguel; Chan, Kok-Gan; Williams, Paul

    2015-11-01

    In Pseudomonas aeruginosa, quorum sensing (QS) regulates the production of secondary metabolites, many of which are antimicrobials that impact on polymicrobial community composition. Consequently, quenching QS modulates the environmental impact of P. aeruginosa. To identify bacteria capable of inactivating the QS signal molecule 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS), a minimal medium containing PQS as the sole carbon source was used to enrich a Malaysian rainforest soil sample. This yielded an Achromobacter xylosoxidans strain (Q19) that inactivated PQS, yielding a new fluorescent compound (I-PQS) confirmed as PQS-derived using deuterated PQS. The I-PQS structure was elucidated using mass spectrometry and nuclear magnetic resonance spectroscopy as 2-heptyl-2-hydroxy-1,2-dihydroquinoline-3,4-dione (HHQD). Achromobacter xylosoxidans Q19 oxidized PQS congeners with alkyl chains ranging from C1 to C5 and also N-methyl PQS, yielding the corresponding 2-hydroxy-1,2-dihydroquinoline-3,4-diones, but was unable to inactivate the PQS precursor HHQ. This indicates that the hydroxyl group at position 3 in PQS is essential and that A. xylosoxidans inactivates PQS via a pathway involving the incorporation of oxygen at C2 of the heterocyclic ring. The conversion of PQS to HHQD also occurred on incubation with 12/17 A. xylosoxidans strains recovered from cystic fibrosis patients, with P. aeruginosa and with Arthrobacter, suggesting that formation of hydroxylated PQS may be a common mechanism of inactivation. PMID:25809238

  2. Fatty Acid Signaling: The New Function of Intracellular Lipases

    PubMed Central

    Papackova, Zuzana; Cahova, Monika

    2015-01-01

    Until recently, intracellular triacylglycerols (TAG) stored in the form of cytoplasmic lipid droplets have been considered to be only passive “energy conserves”. Nevertheless, degradation of TAG gives rise to a pleiotropic spectrum of bioactive intermediates, which may function as potent co-factors of transcription factors or enzymes and contribute to the regulation of numerous cellular processes. From this point of view, the process of lipolysis not only provides energy-rich equivalents but also acquires a new regulatory function. In this review, we will concentrate on the role that fatty acids liberated from intracellular TAG stores play as signaling molecules. The first part provides an overview of the transcription factors, which are regulated by fatty acids derived from intracellular stores. The second part is devoted to the role of fatty acid signaling in different organs/tissues. The specific contribution of free fatty acids released by particular lipases, hormone-sensitive lipase, adipose triacylglycerol lipase and lysosomal lipase will also be discussed. PMID:25674855

  3. Deciphering the link between salicylic acid signaling and sphingolipid metabolism

    PubMed Central

    Sánchez-Rangel, Diana; Rivas-San Vicente, Mariana; de la Torre-Hernández, M. Eugenia; Nájera-Martínez, Manuela; Plasencia, Javier

    2015-01-01

    The field of plant sphingolipid biology has evolved in recent years. Sphingolipids are abundant in cell membranes, and genetic analyses revealed essential roles for these lipids in plant growth, development, and responses to abiotic and biotic stress. Salicylic acid (SA) is a key signaling molecule that is required for induction of defense-related genes and rapid and localized cell death at the site of pathogen infection (hypersensitive response) during incompatible host–pathogen interactions. Conceivably, while levels of SA rapidly increase upon pathogen infection for defense activation, they must be tightly regulated during plant growth and development in the absence of pathogens. Genetic and biochemical evidence suggest that the sphingolipid intermediates, long-chain sphingoid bases, and ceramides, play a role in regulating SA accumulation in plant cells. However, how signals generated from the perturbation of these key sphingolipid intermediates are transduced into the activation of the SA pathway has long remained to be an interesting open question. At least four types of molecules – MAP kinase 6, reactive oxygen species, free calcium, and nitric oxide – could constitute a mechanistic link between sphingolipid metabolism and SA accumulation and signaling. PMID:25806037

  4. L-Ascorbic Acid: A Multifunctional Molecule Supporting Plant Growth and Development

    PubMed Central

    Gallie, Daniel R.

    2013-01-01

    L-Ascorbic acid (vitamin C) is as essential to plants as it is to animals. Ascorbic acid functions as a major redox buffer and as a cofactor for enzymes involved in regulating photosynthesis, hormone biosynthesis, and regenerating other antioxidants. Ascorbic acid regulates cell division and growth and is involved in signal transduction. In contrast to the single pathway responsible for ascorbic acid biosynthesis in animals, plants use multiple pathways to synthesize ascorbic acid, perhaps reflecting the importance of this molecule to plant health. Given the importance of ascorbic acid to human nutrition, several technologies have been developed to increase the ascorbic acid content of plants through the manipulation of biosynthetic or recycling pathways. This paper provides an overview of these approaches as well as the consequences that changes in ascorbic acid content have on plant growth and function. Discussed is the capacity of plants to tolerate changes in ascorbic acid content. The many functions that ascorbic acid serves in plants, however, will require highly targeted approaches to improve their nutritional quality without compromising their health. PMID:24278786

  5. Signaling Lymphocytic Activation Molecule Family Receptor Homologs in New World Monkey Cytomegaloviruses

    PubMed Central

    Pérez-Carmona, Natàlia; Farré, Domènec; Martínez-Vicente, Pablo; Terhorst, Cox; Engel, Pablo

    2015-01-01

    ABSTRACT Throughout evolution, large DNA viruses have been usurping genes from their hosts to equip themselves with proteins that restrain host immune defenses. Signaling lymphocytic activation molecule (SLAM) family (SLAMF) receptors are involved in the regulation of both innate and adaptive immunity, which occurs upon engagement with their ligands via homotypic or heterotypic interactions. Here we report a total of seven SLAMF genes encoded by the genomes of two cytomegalovirus (CMV) species, squirrel monkey CMV (SMCMV) and owl monkey CMV (OMCMV), that infect New World monkeys. Our results indicate that host genes were captured by retrotranscription at different stages of the CMV-host coevolution. The most recent acquisition led to S1 in SMCMV. S1 is a SLAMF6 homolog with an amino acid sequence identity of 97% to SLAMF6 in its ligand-binding N-terminal Ig domain. We demonstrate that S1 is a cell surface glycoprotein capable of binding to host SLAMF6. Furthermore, the OMCMV genome encodes A33, an LY9 (SLAMF3) homolog, and A43, a CD48 (SLAMF2) homolog, two soluble glycoproteins which recognize their respective cellular counterreceptors and thus are likely to be viral SLAMF decoy receptors. In addition, distinct copies of further divergent CD48 homologs were found to be encoded by both CMV genomes. Remarkably, all these molecules display a number of unique features, including cytoplasmic tails lacking characteristic SLAMF signaling motifs. Taken together, our findings indicate a novel immune evasion mechanism in which incorporation of host SLAMF receptors that retain their ligand-binding properties enables viruses to interfere with SLAMF functions and to supply themselves with convenient structural molds for expanding their immunomodulatory repertoires. IMPORTANCE The way in which viruses shape their genomes under the continual selective pressure exerted by the host immune system is central for their survival. Here, we report that New World monkey cytomegaloviruses

  6. Anion photoelectron spectroscopy of acid-base systems, solvated molecules and MALDI matrix molecules

    NASA Astrophysics Data System (ADS)

    Eustis, Soren Newman

    Gas phase, mass-selected, anion photoelectron spectroscopic studies were performed on a variety of molecular systems. These studies can be grouped into three main themes: acid-base interactions, solvation, and ions of analytical interest. Acid-base interactions represent some of the most fundamental processes in chemistry. The study of these processes elucidates elementary principles such as inner and outer sphere complexes, hard and soft ions, and salt formation---to name a few. Apart from their appeal from a pedagogical standpoint, the ubiquity of chemical reactions which involve acids, bases or the resulting salts makes the study of their fundamental interactions both necessary and fruitful. With this in mind, the neutral and anionic series (NH3···HX) (X= F, Cl, Br, I) were examined experimentally and theoretically. The relatively small size of these systems, combined with the advances in computational methods, allowed our experimental results to be compared with very high level ab initio theoretical results. The synergy between theory and experiment yielded an understanding of the nature of the complexes that could not be achieved with either method in isolation. The second theme present in this body or work is molecular solvation. Solvation is a phenomenon which is present in biology, chemistry and physics. Many biological molecules do not become 'active' until they are solvated by water. Thus, the study of biologically relevant species solvated by water is one step in a bottom up approach to studying the biochemical interactions in living organisms. Furthermore, the hydration of acidic molecules in the atmosphere is what drives the formation of 'free' protons or hydronium ions which are the key players in acid driven chemistry. Here are presented two unique solvation studies, Adenine(H2O)-n and C6F6(H2O)-n, these systems are very distinct, but show somewhat similar responses to hydration. The last theme presented in this work is the electronic properties

  7. Ultrasensitive nucleic acid sequence detection by single-molecule electrophoresis

    SciTech Connect

    Castro, A; Shera, E.B.

    1996-09-01

    This is the final report of a one-year laboratory-directed research and development project at Los Alamos National Laboratory. There has been considerable interest in the development of very sensitive clinical diagnostic techniques over the last few years. Many pathogenic agents are often present in extremely small concentrations in clinical samples, especially at the initial stages of infection, making their detection very difficult. This project sought to develop a new technique for the detection and accurate quantification of specific bacterial and viral nucleic acid sequences in clinical samples. The scheme involved the use of novel hybridization probes for the detection of nucleic acids combined with our recently developed technique of single-molecule electrophoresis. This project is directly relevant to the DOE`s Defense Programs strategic directions in the area of biological warfare counter-proliferation.

  8. The multifaceted roles of the interspecies signalling molecule indole in Agrobacterium tumefaciens.

    PubMed

    Lee, Jin-Hyung; Kim, Yong-Guy; Baek, Kwang-Hyun; Cho, Moo Hwan; Lee, Jintae

    2015-04-01

    Bacteria utilize signal molecules to ensure their survival in environmental niches, and indole is an interspecies and interkingdom signalling molecule, which is widespread in the natural environment. In this study, we sought to identify novel roles of indole in soil-borne bacterium Agrobacterium tumefaciens. Agrobacterium tumefaciens was found not to synthesize indole and to degrade it rapidly. The addition of exogenous indole dose-dependently inhibited A. tumefaciens growth and decreased its motility. Surprisingly, indole markedly increased A. tumefaciens biofilm formation on polystyrene, glass and nylon membrane surfaces and enhanced its antibiotic tolerance. Transcriptional analysis showed that indole markedly up-regulated several biofilm-related (celA, cheA, exoR, phoB, flgE, fliR and motA), stress-related genes (clpB, dnaK, gsp, gyrB, marR and soxR) and efflux genes (emrA, norM, and Atu2551) in A. tumefaciens, which partially explained the increased biofilm formation and antibiotic tolerance. In contrast, the plant auxin indole-3-acetic acid did not affect biofilm formation, antibiotic tolerance or gene expression. Interestingly, indole was found to exhibit several similarities with antibiotics, as it inhibited the growth of non-indole-producing bacteria, whereas these bacteria countered its effects by rapidly degrading indole, and by enhancing biofilm formation and antibiotic tolerance. PMID:25040348

  9. [Signaling molecules in the brain and epigenetic factors in neurodegenerative and mental disorders].

    PubMed

    Gomazkov, O A

    2015-01-01

    The literature on a role of signaling molecules in the organization of memory and cognitive functions is analyzed basing on mechanisms of memory physiology determined by a complex of biochemical processes initiated by the transmission of the signal to the synapse and completed by the synthesis of functionally significant molecules in the neuronal genetic apparatus. The center of these processes is a coordinated system of signal transduction, transcription, epigenetic and neurotrophic molecules. The dissonance of signal mechanisms is a prime cause of memory impairment and cognitive dysfunction as social maladaptation factors. The results of experimental and clinical studies of a role of the multilevel signaling system in age-related, neurodegenerative (Alzheimer’s disease) and mental (depression) disorders are discussed. At the same time, signaling molecules may be considered as particular targets for new therapeutic approaches. PMID:26649375

  10. Altered retinoic acid signalling underpins dentition evolution.

    PubMed

    Gibert, Yann; Samarut, Eric; Pasco-Viel, Emmanuel; Bernard, Laure; Borday-Birraux, Véronique; Sadier, Alexa; Labbé, Catherine; Viriot, Laurent; Laudet, Vincent

    2015-03-01

    Small variations in signalling pathways have been linked to phenotypic diversity and speciation. In vertebrates, teeth represent a reservoir of adaptive morphological structures that are prone to evolutionary change. Cyprinid fish display an impressive diversity in tooth number, but the signals that generate such diversity are unknown. Here, we show that retinoic acid (RA) availability influences tooth number size in Cyprinids. Heterozygous adult zebrafish heterozygous for the cyp26b1 mutant that encodes an enzyme able to degrade RA possess an extra tooth in the ventral row. Expression analysis of pharyngeal mesenchyme markers such as dlx2a and lhx6 shows lateral, anterior and dorsal expansion of these markers in RA-treated embryos, whereas the expression of the dental epithelium markers dlx2b and dlx3b is unchanged. Our analysis suggests that changes in RA signalling play an important role in the diversification of teeth in Cyprinids. Our work illustrates that through subtle changes in the expression of rate-limiting enzymes, the RA pathway is an active player of tooth evolution in fish. PMID:25652838

  11. Altered retinoic acid signalling underpins dentition evolution

    PubMed Central

    Gibert, Yann; Samarut, Eric; Pasco-Viel, Emmanuel; Bernard, Laure; Borday-Birraux, Véronique; Sadier, Alexa; Labbé, Catherine; Viriot, Laurent; Laudet, Vincent

    2015-01-01

    Small variations in signalling pathways have been linked to phenotypic diversity and speciation. In vertebrates, teeth represent a reservoir of adaptive morphological structures that are prone to evolutionary change. Cyprinid fish display an impressive diversity in tooth number, but the signals that generate such diversity are unknown. Here, we show that retinoic acid (RA) availability influences tooth number size in Cyprinids. Heterozygous adult zebrafish heterozygous for the cyp26b1 mutant that encodes an enzyme able to degrade RA possess an extra tooth in the ventral row. Expression analysis of pharyngeal mesenchyme markers such as dlx2a and lhx6 shows lateral, anterior and dorsal expansion of these markers in RA-treated embryos, whereas the expression of the dental epithelium markers dlx2b and dlx3b is unchanged. Our analysis suggests that changes in RA signalling play an important role in the diversification of teeth in Cyprinids. Our work illustrates that through subtle changes in the expression of rate-limiting enzymes, the RA pathway is an active player of tooth evolution in fish. PMID:25652838

  12. Integrated magnetic tweezers and single-molecule FRET for investigating the mechanical properties of nucleic acid.

    PubMed

    Long, Xi; Parks, Joseph W; Stone, Michael D

    2016-08-01

    Many enzymes promote structural changes in their nucleic acid substrates via application of piconewton forces over nanometer length scales. Magnetic tweezers (MT) is a single molecule force spectroscopy method widely used for studying the energetics of such mechanical processes. MT permits stable application of a wide range of forces and torques over long time scales with nanometer spatial resolution. However, in any force spectroscopy experiment, the ability to monitor structural changes in nucleic acids with nanometer sensitivity requires the system of interest to be held under high degrees of tension to improve signal to noise. This limitation prohibits measurement of structural changes within nucleic acids under physiologically relevant conditions of low stretching forces. To overcome this challenge, researchers have integrated a spatially sensitive fluorescence spectroscopy method, single molecule-FRET, with MT to allow simultaneous observation and manipulation of nanoscale structural transitions over a wide range of forces. Here, we describe a method for using this hybrid instrument to analyze the mechanical properties of nucleic acids. We expect that this method for analysis of nucleic acid structure will be easily adapted for experiments aiming to interrogate the mechanical responses of other biological macromolecules. PMID:27320203

  13. Conserved nematode signaling molecules elicit plant defenses and pathogen resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nematodes, which are ubiquitous in soil and are estimated to cause $100 B of agricultural damage annually, produce novel, highly conserved small sugar-based molecules call ascarosides. Ascarosides play critical roles in nematode development and behavior. We report here that plants recognize these un...

  14. Difficulties in Laboratory Studies and Astronomical Observations of Organic Molecules: Hydroxyacetone and Lactic Acid

    NASA Technical Reports Server (NTRS)

    Apponi, A. J.; Brewster, M. A.; Hoy, J.; Ziurys, L. M.

    2006-01-01

    For the past 35 years, radio astronomy has revealed a rich organic chemistry in the interstellar gas, which is exceptionally complex towards active star-forming regions. New solar systems condense out of this gas and may influence the evolution of life on newly formed planets. Much of the biologically important functionality is present among the some 130 gas-phase molecules found to date, including alcohols, aldehydes, ketones, acids, amines, amides and even the simplest sugar - glycolaldehyde. Still, many unidentified interstellar radio signals remain, and their identification relies on further laboratory study. The molecules hydroxyacetone and lactic acid are relatively small organic molecules, but possess rather complex rotational spectra owing to their high asymmetry. Hydroxyacetone is particularly problematic because it possess a very low barrier to internal rotation, and exhibits strong coupling of the free-rotor states with the overall rotation of the molecule. As in the case of acetamide, a full decomposition method was employed to order the resultant eigenstates onto normal asymmetric top eigenvectors.

  15. Nitric oxide and salicylic acid signaling in plant defense

    PubMed Central

    Klessig, Daniel F.; Durner, Jörg; Noad, Robert; Navarre, Duroy A.; Wendehenne, David; Kumar, Dhirendra; Zhou, Jun Ma; Shah, Jyoti; Zhang, Shuqun; Kachroo, Pradeep; Trifa, Youssef; Pontier, Dominique; Lam, Eric; Silva, Herman

    2000-01-01

    Salicylic acid (SA) plays a critical signaling role in the activation of plant defense responses after pathogen attack. We have identified several potential components of the SA signaling pathway, including (i) the H2O2-scavenging enzymes catalase and ascorbate peroxidase, (ii) a high affinity SA-binding protein (SABP2), (iii) a SA-inducible protein kinase (SIPK), (iv) NPR1, an ankyrin repeat-containing protein that exhibits limited homology to IκBα and is required for SA signaling, and (v) members of the TGA/OBF family of bZIP transcription factors. These bZIP factors physically interact with NPR1 and bind the SA-responsive element in promoters of several defense genes, such as the pathogenesis-related 1 gene (PR-1). Recent studies have demonstrated that nitric oxide (NO) is another signal that activates defense responses after pathogen attack. NO has been shown to play a critical role in the activation of innate immune and inflammatory responses in animals. Increases in NO synthase (NOS)-like activity occurred in resistant but not susceptible tobacco after infection with tobacco mosaic virus. Here we demonstrate that this increase in activity participates in PR-1 gene induction. Two signaling molecules, cGMP and cyclic ADP ribose (cADPR), which function downstream of NO in animals, also appear to mediate plant defense gene activation (e.g., PR-1). Additionally, NO may activate PR-1 expression via an NO-dependent, cADPR-independent pathway. Several targets of NO in animals, including guanylate cyclase, aconitase, and mitogen-activated protein kinases (e.g., SIPK), are also modulated by NO in plants. Thus, at least portions of NO signaling pathways appear to be shared between plants and animals. PMID:10922045

  16. Structure of Replicating Simian Virus 40 Deoxyribonucleic Acid Molecules 1

    PubMed Central

    Sebring, E. D.; Kelly, T. J.; Thoren, M. M.; Salzman, N. P.

    1971-01-01

    Properties of replicating simian virus 40 (SV40) deoxyribonucleic acid (DNA) have been examined by sedimentation analysis and by direct observation during a lytic cycle of infection of African green monkey kidney cells. Two types of replicating DNA molecules were observed in the electron microscope. One was an open structure containing two branch points, three branches, and no free ends whose length measurements were consistent with those expected for replicating SV40 DNA molecules. A second species had the same features as the open structure, but in addition it contained a superhelix in the unreplicated portion of the molecule. Eighty to ninety per cent of the replicative intermediates (RI) were in this latter configuration, and length measurements of these molecules also were consistent with replicating SV40 DNA. Replicating DNA molecules with this configuration have not been described previously. RI, when examined in ethidium bromide-cesium chloride (EB-CsCl) isopycnic gradients, banded in a heterogeneous manner. A fraction of the RI banded at the same density as circular SV40 DNA containing one or more single-strand nicks (component II). The remaining radioactive RI banded at densities higher than that of component II, and material was present at all densities between that of supercoiled double-stranded DNA (component I) and component II. When RI that banded at different densities in EB-CsCl were examined in alkaline gradients, cosedimentation of parental DNA and newly replicated DNA did not occur. All newly replicated DNA sedimented more slowly than did intact single-stranded SV40 DNA, a finding that is inconsistent with the rolling circle model of DNA replication. An inverse correlation exists between the extent of replication of the SV40 DNA and the banding density in EB-CsCl. Under alkaline conditions, the parental DNA strands that were contained in the RI sedimented as covalently closed structures. The sedimentation rates in alkali of the covalently closed

  17. Molecular Rotation Signals: Molecule Chemistry and Particle Physics

    NASA Astrophysics Data System (ADS)

    Grabow, Jens-Uwe

    2015-06-01

    Molecules - large or small - are attractive academic resources, with numerous questions on their chemical behaviour as well as problems in fundamental physics now (or still) waiting to be answered: Targeted by high-resolution spectroscopy, a rotating molecular top can turn into a laboratory for molecule chemistry or a laboratory for particle physics. Once successfully entrained (many species - depending on size and chemical composition - have insufficient vapour pressures or are of transient nature, such that specifically designed pulsed-jet sources are required for their transfer into the gas phase or in-situ generation) into the collision-free environment of a supersonic-jet expansion, each molecular top comes with its own set of challenges, theoretically and experimentally: Multiple internal interactions are causing complicated energy level schemes and the resulting spectra will be rather difficult to predict theoretically. Experimentally, these spectra are difficult to assess and assign. With today's broad-banded chirp microwave techniques, finding and identifying such spectral features have lost their major drawback of being very time consuming for many molecules. For other molecules, the unrivalled resolution and sensitivity of the narrow-banded impulse microwave techniques provide a window to tackle - at the highest precision available to date - fundamental questions in physics, even particle physics - potentially beyond the standard model. Molecular charge distribution, properties of the chemical bond, details on internal dynamics and intermolecular interaction, the (stereo-chemical) molecular structure (including the possibility of their spatial separation) as well as potential evidence for tiny yet significant interactions encode their signature in pure molecular rotation subjected to time-domain microwave spectroscopic techniques. Ongoing exciting technical developments promise rapid progress. We present recent examples from Hannover, new directions, and

  18. Hyaluronic acid: A key molecule in skin aging

    PubMed Central

    Papakonstantinou, Eleni; Roth, Michael; Karakiulakis, George

    2012-01-01

    Skin aging is a multifactorial process consisting of two distinct and independent mechanisms: intrinsic and extrinsic aging. Youthful skin retains its turgor, resilience and pliability, among others, due to its high content of water. Daily external injury, in addition to the normal process of aging, causes loss of moisture. The key molecule involved in skin moisture is hyaluronic acid (HA) that has unique capacity in retaining water. There are multiple sites for the control of HA synthesis, deposition, cell and protein association and degradation, reflecting the complexity of HA metabolism. The enzymes that synthesize or catabolize HA and HA receptors responsible for many of the functions of HA are all multigene families with distinct patterns of tissue expression. Understanding the metabolism of HA in the different layers of the skin and the interactions of HA with other skin components will facilitate the ability to modulate skin moisture in a rational manner. PMID:23467280

  19. Xanthomonas campestris cell–cell signalling molecule DSF (diffusible signal factor) elicits innate immunity in plants and is suppressed by the exopolysaccharide xanthan

    PubMed Central

    Kakkar, Akanksha; Nizampatnam, Narasimha Rao; Kondreddy, Anil; Pradhan, Binod Bihari; Chatterjee, Subhadeep

    2015-01-01

    Several secreted and surface-associated conserved microbial molecules are recognized by the host to mount the defence response. One such evolutionarily well-conserved bacterial process is the production of cell–cell signalling molecules which regulate production of multiple virulence functions by a process known as quorum sensing. Here it is shown that a bacterial fatty acid cell–cell signalling molecule, DSF (diffusible signal factor), elicits innate immunity in plants. The DSF family of signalling molecules are highly conserved among many phytopathogenic bacteria belonging to the genus Xanthomonas as well as in opportunistic animal pathogens. Using Arabidopsis, Nicotiana benthamiana, and rice as model systems, it is shown that DSF induces a hypersensitivity reaction (HR)-like response, programmed cell death, the accumulation of autofluorescent compounds, hydrogen peroxide production, and the expression of the PATHOGENESIS-RELATED1 (PR-1) gene. Furthermore, production of the DSF signalling molecule in Pseudomonas syringae, a non-DSF-producing plant pathogen, induces the innate immune response in the N. benthamiana host plant and also affects pathogen growth. By pre- and co-inoculation of DSF, it was demonstrated that the DSF-induced plant defence reduces disease severity and pathogen growth in the host plant. In this study, it was further demonstrated that wild-type Xanthomonas campestris suppresses the DSF-induced innate immunity by secreting xanthan, the main component of extracellular polysaccharide. The results indicate that plants have evolved to recognize a widely conserved bacterial communication system and may have played a role in the co-evolution of host recognition of the pathogen and the communication machinery. PMID:26248667

  20. Xanthomonas campestris cell-cell signalling molecule DSF (diffusible signal factor) elicits innate immunity in plants and is suppressed by the exopolysaccharide xanthan.

    PubMed

    Kakkar, Akanksha; Nizampatnam, Narasimha Rao; Kondreddy, Anil; Pradhan, Binod Bihari; Chatterjee, Subhadeep

    2015-11-01

    Several secreted and surface-associated conserved microbial molecules are recognized by the host to mount the defence response. One such evolutionarily well-conserved bacterial process is the production of cell-cell signalling molecules which regulate production of multiple virulence functions by a process known as quorum sensing. Here it is shown that a bacterial fatty acid cell-cell signalling molecule, DSF (diffusible signal factor), elicits innate immunity in plants. The DSF family of signalling molecules are highly conserved among many phytopathogenic bacteria belonging to the genus Xanthomonas as well as in opportunistic animal pathogens. Using Arabidopsis, Nicotiana benthamiana, and rice as model systems, it is shown that DSF induces a hypersensitivity reaction (HR)-like response, programmed cell death, the accumulation of autofluorescent compounds, hydrogen peroxide production, and the expression of the PATHOGENESIS-RELATED1 (PR-1) gene. Furthermore, production of the DSF signalling molecule in Pseudomonas syringae, a non-DSF-producing plant pathogen, induces the innate immune response in the N. benthamiana host plant and also affects pathogen growth. By pre- and co-inoculation of DSF, it was demonstrated that the DSF-induced plant defence reduces disease severity and pathogen growth in the host plant. In this study, it was further demonstrated that wild-type Xanthomonas campestris suppresses the DSF-induced innate immunity by secreting xanthan, the main component of extracellular polysaccharide. The results indicate that plants have evolved to recognize a widely conserved bacterial communication system and may have played a role in the co-evolution of host recognition of the pathogen and the communication machinery. PMID:26248667

  1. Modulation of Host Biology by Pseudomonas aeruginosa Quorum Sensing Signal Molecules: Messengers or Traitors

    PubMed Central

    Liu, Yi-Chia; Chan, Kok-Gan; Chang, Chien-Yi

    2015-01-01

    Bacterial cells sense their population density and respond accordingly by producing various signal molecules to the surrounding environments thereby trigger a plethora of gene expression. This regulatory pathway is termed quorum sensing (QS). Plenty of bacterial virulence factors are controlled by QS or QS-mediated regulatory systems and QS signal molecules (QSSMs) play crucial roles in bacterial signaling transduction. Moreover, bacterial QSSMs were shown to interfere with host cell signaling and modulate host immune responses. QSSMs not only regulate the expression of bacterial virulence factors but themselves act in the modulation of host biology that can be potential therapeutic targets. PMID:26617576

  2. Photoelectron circular dichroism of the randomly oriented chiral molecules glyceraldehyde and lactic acid

    NASA Astrophysics Data System (ADS)

    Powis, Ivan

    2000-01-01

    The differing interaction of left and right circularly polarized light with chiral molecules is shown to lead to different angular distributions of the photoelectrons created by photoionization of a given enantiomer, even when the target molecules are randomly oriented. Numerical calculations are presented to demonstrate the magnitude of this effect for the C3H6O3 structural isomers lactic acid and glyceraldehyde, including two different conformations of the latter. Circular dichroism in the angular distributions (CDAD) of the valence electrons of these biomolecules is most pronounced close to threshold, but tends to vanish as the electron kinetic energy approaches 20 eV and above. CDAD signals are predicted to range, typically, from 10% to 40% and sometimes to more than 60% of the differential cross section.

  3. Ferulic acid attenuates adhesion molecule expression in gamma-radiated human umbilical vascular endothelial cells.

    PubMed

    Ma, Zeng-Chun; Hong, Qian; Wang, Yu-Guang; Tan, Hong-Ling; Xiao, Cheng-Rong; Liang, Qian-De; Cai, Shao-Hua; Gao, Yue

    2010-01-01

    Radiation induces an important inflammatory response in the irradiated organs, characterized by leukocyte infiltration and vascular changes. Since adhesion molecules play an important role in facilitating the immune response at the inflammation sites, interfering with the expression of these molecules may be an important therapeutic target of radiation induced inflammation. Many adhesion molecules such as intercellular cell adhesion molecule 1 (ICAM-1), and vascular cell adhesion molecule 1 (VCAM-1) have been identified in radiation. Ferulic acid (FA), an effective radioprotector during radiotherapy, is widely used in endothelium protection. The present study examined the effect of FA on the induction of adhesion molecules by gamma-radiation and the mechanisms of its effect in gamma-irradiated human umbilical vein endothelial cells (HUVECs). HUVECs were pretreated for 18 h with FA and then exposed to 10 Gy radiation. The result of cell adhesion assay showed FA inhibited radiation-induced U937 adhesion to HUVECs. FA prevented induction of ICAM-1 and VCAM-1 expression in a concentration-dependent manner after stimulation with radiation at the level of mRNA and protein. Inhibitors of the extracellular signal regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) pathways were used to determine which pathway was involved in FA action; the result showed that the inhibitory effect of FA on adhesion molecule expression was mediated by the blockade of JNK. FA appears to be a potential therapeutic agent for treating various inflammatory disorders including radiation induced inflammation. PMID:20460750

  4. Small molecule activation of NOTCH signaling inhibits acute myeloid leukemia

    PubMed Central

    Ye, Qi; Jiang, Jue; Zhan, Guanqun; Yan, Wanyao; Huang, Liang; Hu, Yufeng; Su, Hexiu; Tong, Qingyi; Yue, Ming; Li, Hua; Yao, Guangmin; Zhang, Yonghui; Liu, Hudan

    2016-01-01

    Aberrant activation of the NOTCH signaling pathway is crucial for the onset and progression of T cell leukemia. Yet recent studies also suggest a tumor suppressive role of NOTCH signaling in acute myeloid leukemia (AML) and reactivation of this pathway offers an attractive opportunity for anti-AML therapies. N-methylhemeanthidine chloride (NMHC) is a novel Amaryllidaceae alkaloid that we previously isolated from Zephyranthes candida, exhibiting inhibitory activities in a variety of cancer cells, particularly those from AML. Here, we report NMHC not only selectively inhibits AML cell proliferation in vitro but also hampers tumor development in a human AML xenograft model. Genome-wide gene expression profiling reveals that NMHC activates the NOTCH signaling. Combination of NMHC and recombinant human NOTCH ligand DLL4 achieves a remarkable synergistic effect on NOTCH activation. Moreover, pre-inhibition of NOTCH by overexpression of dominant negative MAML alleviates NMHC-mediated cytotoxicity in AML. Further mechanistic analysis using structure-based molecular modeling as well as biochemical assays demonstrates that NMHC docks in the hydrophobic cavity within the NOTCH1 negative regulatory region (NRR), thus promoting NOTCH1 proteolytic cleavage. Our findings thus establish NMHC as a potential NOTCH agonist that holds great promises for future development as a novel agent beneficial to patients with AML. PMID:27211848

  5. Small molecule activation of NOTCH signaling inhibits acute myeloid leukemia.

    PubMed

    Ye, Qi; Jiang, Jue; Zhan, Guanqun; Yan, Wanyao; Huang, Liang; Hu, Yufeng; Su, Hexiu; Tong, Qingyi; Yue, Ming; Li, Hua; Yao, Guangmin; Zhang, Yonghui; Liu, Hudan

    2016-01-01

    Aberrant activation of the NOTCH signaling pathway is crucial for the onset and progression of T cell leukemia. Yet recent studies also suggest a tumor suppressive role of NOTCH signaling in acute myeloid leukemia (AML) and reactivation of this pathway offers an attractive opportunity for anti-AML therapies. N-methylhemeanthidine chloride (NMHC) is a novel Amaryllidaceae alkaloid that we previously isolated from Zephyranthes candida, exhibiting inhibitory activities in a variety of cancer cells, particularly those from AML. Here, we report NMHC not only selectively inhibits AML cell proliferation in vitro but also hampers tumor development in a human AML xenograft model. Genome-wide gene expression profiling reveals that NMHC activates the NOTCH signaling. Combination of NMHC and recombinant human NOTCH ligand DLL4 achieves a remarkable synergistic effect on NOTCH activation. Moreover, pre-inhibition of NOTCH by overexpression of dominant negative MAML alleviates NMHC-mediated cytotoxicity in AML. Further mechanistic analysis using structure-based molecular modeling as well as biochemical assays demonstrates that NMHC docks in the hydrophobic cavity within the NOTCH1 negative regulatory region (NRR), thus promoting NOTCH1 proteolytic cleavage. Our findings thus establish NMHC as a potential NOTCH agonist that holds great promises for future development as a novel agent beneficial to patients with AML. PMID:27211848

  6. Modulation of BKCa channel gating by endogenous signaling molecules

    PubMed Central

    Hou, Shangwei; Heinemann, Stefan H.; Hoshi, Toshinori

    2010-01-01

    Large-conductance Ca2+- and voltage-activated K+ (BKCa, MaxiK or Slo1) channels are expressed in almost every tissue in our body and participate in many critical functions such as neuronal excitability, vascular tone regulation and neurotransmitter release. The functional versatility of BKCa channels owes in part to the availability of a spectacularly wide array of biological modulators of the channel function. In this review, we focus on modulation of BKCa channels by small endogenous molecules, emphasizing their molecular mechanisms. The mechanistic information available from studies on the small naturally occurring modulators is expected to contribute to our understanding of the physiological and pathophysiological roles of BKCa channels. PMID:19196649

  7. D-aspartate acts as a signaling molecule in nervous and neuroendocrine systems

    PubMed Central

    Ota, Nobutoshi; Shi, Ting; Sweedler, Jonathan V.

    2013-01-01

    D-Aspartate (D-Asp) is an endogenous amino acid in the central nervous and reproductive systems of vertebrates and invertebrates. High concentrations of D-Asp are found in distinct anatomical locations, suggesting that it has specific physiological roles in animals. Many of the characteristics of D-Asp have been documented, including its tissue and cellular distribution, formation and degradation, as well as the responses elicited by D-Asp application. D-Asp performs important roles related to nervous system development and hormone regulation; in addition, it appears to act as a cell-to-cell signaling molecule. Recent studies have shown that D-Asp fulfills many, if not all, of the definitions of a classical neurotransmitter—that the molecule’s biosynthesis, degradation, uptake, and release take place within the presynaptic neuron, and that it triggers a response in the postsynaptic neuron after its release. Accumulating evidence suggests that these criteria are met by a heterogeneous distribution of enzymes for D-Asp’s biosynthesis and degradation, an appropriate uptake mechanism, localization within synaptic vesicles, and a postsynaptic response via an ionotropic receptor. Although D-Asp receptors remain to be characterized, the postsynaptic response of D-Asp has been studied and several L-glutamate receptors are known to respond to D-Asp. In this review we discuss the current status of research on D-Asp in neuronal and neuroendocrine systems, and highlight results that support D-Asp’s role as a signaling molecule. PMID:22872108

  8. Determining molecule diffusion coefficients on surfaces from a locally fixed probe: Analysis of signal fluctuations

    NASA Astrophysics Data System (ADS)

    Hahne, Susanne; Ikonomov, Julian; Sokolowski, Moritz; Maass, Philipp

    2013-02-01

    Methods of determining surface diffusion coefficients of molecules from signal fluctuations of a locally fixed probe are revisited and refined. Particular emphasis is put on the influence of the molecule's extent. In addition to the formerly introduced autocorrelation method and residence time method, we develop a further method based on the distribution of intervals between successive peaks in the signal. The theoretical findings are applied to scanning tunneling microscopy measurements of copper phthalocyanine (CuPc) molecules on the Ag(100) surface. We discuss advantages and disadvantages of each method and suggest a combination to obtain accurate results for diffusion coefficients.

  9. Small molecule aptamer assays based on fluorescence anisotropy signal-enhancer oligonucleotides.

    PubMed

    Perrier, Sandrine; Bouilloud, Prisca; De Oliveira Coelho, Gisella; Henry, Mickael; Peyrin, Eric

    2016-08-15

    Herein, we design novel fluorescence anisotropy (FA) aptamer sensing platforms dedicated to small molecule detection. The assay strategy relied on enhanced fluctuations of segmental motion dynamics of the aptamer tracer mediated by an unlabelled, partially complementary oligonucleotide. The signal-enhancer oligonucleotide (SEO) essentially served as a free probe fraction revealer. By targeting specific regions of the signalling functional nucleic acid, the SEO binding to the unbound aptamer triggered perturbations of both the internal DNA flexibility and the localized dye environment upon the free probe to duplex structure transition. This potentiating effect determined increased FA variations between the duplex and target bound states of the aptameric probe. FA assay responses were obtained with both pre-structured (adenosine) and unstructured (tyrosinamide) aptamers and with dyes of different photochemical properties (fluorescein and texas red). The multiplexed analysis ability was further demonstrated through the simultaneous multicolour detection of the two small targets. The FA method appears to be especially simple, sensitive and widely applicable. PMID:27085946

  10. All-optical signal processing at 10 GHz using a photonic crystal molecule

    SciTech Connect

    Combrié, Sylvain; Lehoucq, Gaëlle; Junay, Alexandra; De Rossi, Alfredo; Malaguti, Stefania; Bellanca, Gaetano; Trillo, Stefano; Ménager, Loic; Peter Reithmaier, Johann

    2013-11-04

    We report on 10 GHz operation of an all-optical gate based on an Indium Phosphide Photonic Crystal Molecule. Wavelength conversion and all-optical mixing of microwave signals are demonstrated using the 2 mW output of a mode locked diode laser. The spectral separation of the optical pump and signal is crucial in suppressing optical cross-talk.

  11. Hydrogen sulphide in cardiovascular system: A cascade from interaction between sulphur atoms and signalling molecules.

    PubMed

    Wang, Ming-Jie; Cai, Wen-Jie; Zhu, Yi-Chun

    2016-05-15

    As a gasotransmitter, hydrogen sulphide exerts its extensive physiological and pathophysiological effects in mammals. The interaction between sulphur atoms and signalling molecules forms a cascade that modulates cellular functions and homeostasis. In this review, we focus on the signalling mechanism underlying the effect of hydrogen sulphide in the cardiovascular system and metabolism as well as the biological relevance to human diseases. PMID:27071836

  12. Coherent (photon) vs incoherent (current) detection of multidimensional optical signals from single molecules in open junctions

    SciTech Connect

    Agarwalla, Bijay Kumar; Hua, Weijie; Zhang, Yu; Mukamel, Shaul; Harbola, Upendra

    2015-06-07

    The nonlinear optical response of a current-carrying single molecule coupled to two metal leads and driven by a sequence of impulsive optical pulses with controllable phases and time delays is calculated. Coherent (stimulated, heterodyne) detection of photons and incoherent detection of the optically induced current are compared. Using a diagrammatic Liouville space superoperator formalism, the signals are recast in terms of molecular correlation functions which are then expanded in the many-body molecular states. Two dimensional signals in benzene-1,4-dithiol molecule show cross peaks involving charged states. The correlation between optical and charge current signal is also observed.

  13. NALDB: nucleic acid ligand database for small molecules targeting nucleic acid

    PubMed Central

    Kumar Mishra, Subodh; Kumar, Amit

    2016-01-01

    Nucleic acid ligand database (NALDB) is a unique database that provides detailed information about the experimental data of small molecules that were reported to target several types of nucleic acid structures. NALDB is the first ligand database that contains ligand information for all type of nucleic acid. NALDB contains more than 3500 ligand entries with detailed pharmacokinetic and pharmacodynamic information such as target name, target sequence, ligand 2D/3D structure, SMILES, molecular formula, molecular weight, net-formal charge, AlogP, number of rings, number of hydrogen bond donor and acceptor, potential energy along with their Ki, Kd, IC50 values. All these details at single platform would be helpful for the development and betterment of novel ligands targeting nucleic acids that could serve as a potential target in different diseases including cancers and neurological disorders. With maximum 255 conformers for each ligand entry, our database is a multi-conformer database and can facilitate the virtual screening process. NALDB provides powerful web-based search tools that make database searching efficient and simplified using option for text as well as for structure query. NALDB also provides multi-dimensional advanced search tool which can screen the database molecules on the basis of molecular properties of ligand provided by database users. A 3D structure visualization tool has also been included for 3D structure representation of ligands. NALDB offers an inclusive pharmacological information and the structurally flexible set of small molecules with their three-dimensional conformers that can accelerate the virtual screening and other modeling processes and eventually complement the nucleic acid-based drug discovery research. NALDB can be routinely updated and freely available on bsbe.iiti.ac.in/bsbe/naldb/HOME.php. Database URL: http://bsbe.iiti.ac.in/bsbe/naldb/HOME.php PMID:26896846

  14. NALDB: nucleic acid ligand database for small molecules targeting nucleic acid.

    PubMed

    Kumar Mishra, Subodh; Kumar, Amit

    2016-01-01

    Nucleic acid ligand database (NALDB) is a unique database that provides detailed information about the experimental data of small molecules that were reported to target several types of nucleic acid structures. NALDB is the first ligand database that contains ligand information for all type of nucleic acid. NALDB contains more than 3500 ligand entries with detailed pharmacokinetic and pharmacodynamic information such as target name, target sequence, ligand 2D/3D structure, SMILES, molecular formula, molecular weight, net-formal charge, AlogP, number of rings, number of hydrogen bond donor and acceptor, potential energy along with their Ki, Kd, IC50 values. All these details at single platform would be helpful for the development and betterment of novel ligands targeting nucleic acids that could serve as a potential target in different diseases including cancers and neurological disorders. With maximum 255 conformers for each ligand entry, our database is a multi-conformer database and can facilitate the virtual screening process. NALDB provides powerful web-based search tools that make database searching efficient and simplified using option for text as well as for structure query. NALDB also provides multi-dimensional advanced search tool which can screen the database molecules on the basis of molecular properties of ligand provided by database users. A 3D structure visualization tool has also been included for 3D structure representation of ligands. NALDB offers an inclusive pharmacological information and the structurally flexible set of small molecules with their three-dimensional conformers that can accelerate the virtual screening and other modeling processes and eventually complement the nucleic acid-based drug discovery research. NALDB can be routinely updated and freely available on bsbe.iiti.ac.in/bsbe/naldb/HOME.php. Database URL: http://bsbe.iiti.ac.in/bsbe/naldb/HOME.php. PMID:26896846

  15. Root-Shoot Signaling crosstalk involved in the shoot growth promoting action of rhizospheric humic acids

    PubMed Central

    Olaetxea, Maite; Mora, Verónica; García, Andrés Calderin; Santos, Leandro Azevedo; Baigorri, Roberto; Fuentes, Marta; Garnica, María; Berbara, Ricardo Luis Louro; Zamarreño, Angel Maria; Garcia-Mina, Jose M.

    2016-01-01

    ABSTRACT Numerous studies have shown the ability of humic substances to improve plant development. This action is normally reflected in an enhancement of crop yields and quality. However, the mechanisms responsible for this action of humic substances remain rather unknown. Our studies have shown that the shoot promoting action of sedimentary humic acids is dependent of its ability to increase root hydraulic conductivity through signaling pathways related to ABA, which in turn is affected in roots by humic acids in an IAA-NO dependent way. Furthermore, these studies also indicate that the primary action of humic acids in roots might also be physical, resulting from a transient mild stress caused by humic acids associated with a fouling-cleaning cycle of wall cell pores. Finally the role of alternative signal molecules, such as ROS, and corresponding signaling pathways are also discussed and modeled in the context of the above-mentioned framework. PMID:26966789

  16. The effect of CD4 receptor downregulation and its downstream signaling molecules on HIV-1 latency

    SciTech Connect

    Kim, Kyung-Chang; Kim, Hyeon Guk; Roh, Tae-Young; Park, Jihwan; Jung, Kyung-Min; Lee, Joo-Shil; Choi, Sang-Yun; Kim, Sung Soon; Choi, Byeong-Sun

    2011-01-14

    Research highlights: {yields} CD4 receptors were downregulated on the surface of HIV-1 latently infected cells. {yields} CD4 downstream signaling molecules were suppressed in HIV-1 latently infected cells. {yields} HIV-1 progeny can be reactivated by induction of T-cell activation signal molecules. {yields} H3K4me3 and H3K9ac were highly enriched in CD4 downstream signaling molecules. {yields} HIV-1 latency can be maintained by the reduction of downstream signaling molecules. -- Abstract: HIV-1 can establish a latent infection in memory CD4 + T cells to evade the host immune response. CD4 molecules can act not only as the HIV-1 receptor for entry but also as the trigger in an intracellular signaling cascade for T-cell activation and proliferation via protein tyrosine kinases. Novel chronic HIV-1-infected A3.01-derived (NCHA) cells were used to examine the involvement of CD4 downstream signaling in HIV-1 latency. CD4 receptors in NCHA cells were dramatically downregulated on its surface but were slightly decreased in whole-cell lysates. The expression levels of CD4 downstream signaling molecules, including P56{sup Lck}, ZAP-70, LAT, and c-Jun, were sharply decreased in NCHA cells. The lowered histone modifications of H3K4me3 and H3K9ac correlated with the downregulation of P56{sup Lck}, ZAP-70, and LAT in NCHA cells. AP-1 binding activity was also reduced in NCHA cells. LAT and c-Jun suppressed in NCHA cells were highly induced after PMA treatment. In epigenetic analysis, other signal transduction molecules which are associated with active and/or latent HIV-1 infection showed normal states in HIV-1 latently infected cells compared to A3.01 cells. In conclusion, we demonstrated that the HIV-1 latent state is sustained by the reduction of downstream signaling molecules via the downregulation of CD4 and the attenuated activity of transcription factor as AP-1. The HIV-1 latency model via T-cell deactivation may provide some clues for the development of the new

  17. A pathway to bone: signaling molecules and transcription factors involved in chondrocyte development and maturation

    PubMed Central

    Kozhemyakina, Elena; Lassar, Andrew B.; Zelzer, Elazar

    2015-01-01

    Decades of work have identified the signaling pathways that regulate the differentiation of chondrocytes during bone formation, from their initial induction from mesenchymal progenitor cells to their terminal maturation into hypertrophic chondrocytes. Here, we review how multiple signaling molecules, mechanical signals and morphological cell features are integrated to activate a set of key transcription factors that determine and regulate the genetic program that induces chondrogenesis and chondrocyte differentiation. Moreover, we describe recent findings regarding the roles of several signaling pathways in modulating the proliferation and maturation of chondrocytes in the growth plate, which is the ‘engine’ of bone elongation. PMID:25715393

  18. Quorum Sensing Signaling Molecules Produced by Reference and Emerging Soft-Rot Bacteria (Dickeya and Pectobacterium spp.)

    PubMed Central

    Crépin, Alexandre; Barbey, Corinne; Beury-Cirou, Amélie; Hélias, Valérie; Taupin, Laure; Reverchon, Sylvie; Nasser, William; Faure, Denis; Dufour, Alain; Orange, Nicole; Feuilloley, Marc; Heurlier, Karin; Burini, Jean-François; Latour, Xavier

    2012-01-01

    Background Several small diffusible molecules are involved in bacterial quorum sensing and virulence. The production of autoinducers-1 and -2, quinolone, indole and γ-amino butyrate signaling molecules was investigated in a set of soft-rot bacteria belonging to six Dickeya or Pectobacterium species including recent or emerging potato isolates. Methodology/Principal Findings Using bacterial biosensors, immunoassay, and chromatographic analysis, we showed that soft-rot bacteria have the common ability to produce transiently during their exponential phase of growth the N-3-oxo-hexanoyl- or the N-3-oxo-octanoyl-l-homoserine lactones and a molecule of the autoinducer-2 family. Dickeya spp. produced in addition the indole-3-acetic acid in tryptophan-rich conditions. All these signaling molecules have been identified for the first time in the novel Dickeya solani species. In contrast, quinolone and γ-amino butyrate signals were not identified and the corresponding synthases are not present in the available genomes of soft-rot bacteria. To determine if the variations of signal production according to growth phase could result from expression modifications of the corresponding synthase gene, the respective mRNA levels were estimated by reverse transcriptase-PCR. While the N-acyl-homoserine lactone production is systematically correlated to the synthase expression, that of the autoinducer-2 follows the expression of an enzyme upstream in the activated methyl cycle and providing its precursor, rather than the expression of its own synthase. Conclusions/Significance Despite sharing the S-adenosylmethionine precursor, no strong link was detected between the production kinetics or metabolic pathways of autoinducers-1 and -2. In contrast, the signaling pathway of autoinducer-2 seems to be switched off by the indole-3-acetic acid pathway under tryptophan control. It therefore appears that the two genera of soft-rot bacteria have similarities but also differences in the

  19. Signal Molecules Mediate the Impact of the Earthworm Aporrectodea caliginosa on Growth, Development and Defence of the Plant Arabidopsis thaliana

    PubMed Central

    Puga-Freitas, Ruben; Barot, Sébastien; Taconnat, Ludivine; Renou, Jean-Pierre; Blouin, Manuel

    2012-01-01

    Earthworms have generally a positive impact on plant growth, which is often attributed to a trophic mechanism: namely, earthworms increase the release of mineral nutrients from soil litter and organic matter. An alternative hypothesis has been proposed since the discovery of a signal molecule (Indole Acetic Acid) in earthworm faeces. In this study, we used methodologies developed in plant science to gain information on ecological mechanisms involved in plant-earthworm interaction, by looking at plant response to earthworm presence at a molecular level. First, we looked at plant overall response to earthworm faeces in an in vitro device where only signal molecules could have an effect on plant growth; we observed that earthworms were inducing positive or negative effects on different plant species. Then, using an Arabidopsis thaliana mutant with an impaired auxin transport, we demonstrated the potential of earthworms to stimulate root growth and to revert the dwarf mutant phenotype. Finally, we performed a comparative transcriptomic analysis of Arabidopsis thaliana in the presence and absence of earthworms; we found that genes modulated in the presence of earthworms are known to respond to biotic and abiotic stresses, or to the application of exogenous hormones. A comparison of our results with other studies found in databases revealed strong analogies with systemic resistance, induced by signal molecules emitted by Plant Growth Promoting Rhizobacteria and/or elicitors emitted by non-virulent pathogens. Signal molecules such as auxin and ethylene, which are considered as major in plant-microorganisms interactions, can also be of prior importance to explain plant-macroinvertebrates interactions. This could imply revisiting ecological theories which generally stress on the role of trophic relationships. PMID:23226498

  20. Role of mTOR Downstream Effector Signaling Molecules in Francisella Tularensis Internalization by Murine Macrophages

    PubMed Central

    Edwards, Michael W.; Aultman, James A.; Harber, Gregory; Bhatt, Jay M.; Sztul, Elizabeth; Xu, Qingan; Zhang, Ping; Michalek, Suzanne M.; Katz, Jannet

    2013-01-01

    Francisella tularensis is an infectious, gram-negative, intracellular microorganism, and the cause of tularemia. Invasion of host cells by intracellular pathogens like Francisella is initiated by their interaction with different host cell membrane receptors and the rapid phosphorylation of different downstream signaling molecules. PI3K and Syk have been shown to be involved in F. tularensis host cell entry, and both of these signaling molecules are associated with the master regulator serine/threonine kinase mTOR; yet the involvement of mTOR in F. tularensis invasion of host cells has not been assessed. Here, we report that infection of macrophages with F. tularensis triggers the phosphorylation of mTOR downstream effector molecules, and that signaling via TLR2 is necessary for these events. Inhibition of mTOR or of PI3K, ERK, or p38, but not Akt signaling, downregulates the levels of phosphorylation of mTOR downstream targets, and significantly reduces the number of F. tularensis cells invading macrophages. Moreover, while phosphorylation of mTOR downstream effectors occurs via the PI3K pathway, it also involves PLCγ1 and Ca2+ signaling. Furthermore, abrogation of PLC or Ca2+ signaling revealed their important role in the ability of F. tularensis to invade host cells. Together, these findings suggest that F. tularensis invasion of primary macrophages utilize a myriad of host signaling pathways to ensure effective cell entry. PMID:24312679

  1. Effects of an EGFR-binding affibody molecule on intracellular signaling pathways.

    PubMed

    Nordberg, E; Ekerljung, L; Sahlberg, S H; Carlsson, J; Lennartsson, J; Glimelius, B

    2010-04-01

    Effects on intracellular signaling were studied in cells treated with the affibody molecule (ZEGFR:955)2 that targets the epithelial growth factor receptor (EGFR). EGFR is overexpressed in many types of cancers and plays a fundamental role in cell signaling and it is of interest to find targeting agents capable of blocking the receptor. The clinically approved antibody cetuximab (Erbitux) and the natural ligand EGF were included as reference molecules. Two EGFR-rich cell lines, A-431 and U-343, were exposed to the three targeting agents and lysed. The cell lysates were immunoprecipitated with the receptors, or directly separated by SDS-Page. Autophosphorylation of the receptors and phosphorylation of the downstream signaling proteins Erk and Akt, were evaluated by Western blotting. Although the three different agents compete for the same binding site on EGFR, they influenced the signaling differently. The affibody molecule did not induce autophosphorylation of EGFR or any other receptor in the EGFR-family but, in spite of this, induced phosphorylation of Erk in both cell lines and Akt in the A-431 cells. Thus, the results suggest that the signaling pattern induced by (ZEGFR:955)2 is only partly similar to that induced by cetuximab. This makes the affibody molecule a potentially interesting alternative to cetuximab for EGFR-targeted therapy since it might give different therapy-related effects on tumor cells and different side effects on normal tissues. PMID:20198342

  2. SigMol: repertoire of quorum sensing signaling molecules in prokaryotes

    PubMed Central

    Rajput, Akanksha; Kaur, Karambir; Kumar, Manoj

    2016-01-01

    Quorum sensing is a widespread phenomenon in prokaryotes that helps them to communicate among themselves and with eukaryotes. It is driven through quorum sensing signaling molecules (QSSMs) in a density dependent manner that assists in numerous biological functions like biofilm formation, virulence factors secretion, swarming motility, bioluminescence, etc. Despite immense implications, dedicated resources of QSSMs are lacking. Therefore, we have developed SigMol (http://bioinfo.imtech.res.in/manojk/sigmol), a specialized repository of these molecules in prokaryotes. SigMol harbors information on QSSMs pertaining to different quorum sensing signaling systems namely acylated homoserine lactones (AHLs), diketopiperazines (DKPs), 4-hydroxy-2-alkylquinolines (HAQs), diffusible signal factors (DSFs), autoinducer-2 (AI-2) and others. Database contains 1382 entries of 182 unique signaling molecules from 215 organisms. It encompasses biological as well as chemical aspects of signaling molecules. Biological information includes genes, preliminary bioassays, identification assays and applications, while chemical detail comprises of IUPAC name, SMILES and structure. We have provided user-friendly browsing and searching facilities for easy data retrieval and comparison. We have gleaned information of diverse QSSMs reported in literature at a single platform ‘SigMol’. This comprehensive resource will assist the scientific community in understanding intraspecies, interspecies or interkingdom networking and further help to unfold different facets of quorum sensing and related therapeutics. PMID:26490957

  3. SigMol: repertoire of quorum sensing signaling molecules in prokaryotes.

    PubMed

    Rajput, Akanksha; Kaur, Karambir; Kumar, Manoj

    2016-01-01

    Quorum sensing is a widespread phenomenon in prokaryotes that helps them to communicate among themselves and with eukaryotes. It is driven through quorum sensing signaling molecules (QSSMs) in a density dependent manner that assists in numerous biological functions like biofilm formation, virulence factors secretion, swarming motility, bioluminescence, etc. Despite immense implications, dedicated resources of QSSMs are lacking. Therefore, we have developed SigMol (http://bioinfo.imtech.res.in/manojk/sigmol), a specialized repository of these molecules in prokaryotes. SigMol harbors information on QSSMs pertaining to different quorum sensing signaling systems namely acylated homoserine lactones (AHLs), diketopiperazines (DKPs), 4-hydroxy-2-alkylquinolines (HAQs), diffusible signal factors (DSFs), autoinducer-2 (AI-2) and others. Database contains 1382: entries of 182: unique signaling molecules from 215: organisms. It encompasses biological as well as chemical aspects of signaling molecules. Biological information includes genes, preliminary bioassays, identification assays and applications, while chemical detail comprises of IUPAC name, SMILES and structure. We have provided user-friendly browsing and searching facilities for easy data retrieval and comparison. We have gleaned information of diverse QSSMs reported in literature at a single platform 'SigMol'. This comprehensive resource will assist the scientific community in understanding intraspecies, interspecies or interkingdom networking and further help to unfold different facets of quorum sensing and related therapeutics. PMID:26490957

  4. Very long chain fatty acid and lipid signaling in the response of plants to pathogens

    PubMed Central

    Raffaele, Sylvain; Leger, Amandine

    2009-01-01

    Recent findings indicate that lipid signaling is essential for plant resistance to pathogens. Besides oxylipins and unsaturated fatty acids known to play important signaling functions during plant-pathogen interactions, the very long chain fatty acid (VLCFA) biosynthesis pathway has been recently associated to plant defense through different aspects. VLCFAs are indeed required for the biosynthesis of the plant cuticle and the generation of sphingolipids. Elucidation of the roles of these lipids in biotic stress responses is the result of the use of genetic approaches together with the identification of the genes/proteins involved in their biosynthesis. This review focuses on recent observations which revealed the complex function of the cuticle and cuticle-derived signals, and the key role of sphingolipids as bioactive molecules involved in signal transduction and cell death regulation during plant-pathogen interactions. PMID:19649180

  5. Basic roles of key molecules connected with NMDAR signaling pathway on regulating learning and memory and synaptic plasticity.

    PubMed

    Wang, Hui; Peng, Rui-Yun

    2016-01-01

    With key roles in essential brain functions ranging from the long-term potentiation (LTP) to synaptic plasticity, the N-methyl-D-aspartic acid receptor (NMDAR) can be considered as one of the fundamental glutamate receptors in the central nervous system. The role of NMDA R was first identified in synaptic plasticity and has been extensively studied. Some molecules, such as Ca(2+), postsynaptic density 95 (PSD-95), calcium/calmodulin-dependent protein kinase II (CaMK II), protein kinase A (PKA), mitogen-activated protein kinase (MAPK) and cyclic adenosine monophosphate (cAMP) responsive element binding protein (CREB), are of special importance in learning and memory. This review mainly focused on the new research of key molecules connected with learning and memory, which played important roles in the NMDAR signaling pathway. PMID:27583167

  6. Amino acid transporters: roles in amino acid sensing and signalling in animal cells.

    PubMed Central

    Hyde, Russell; Taylor, Peter M; Hundal, Harinder S

    2003-01-01

    Amino acid availability regulates cellular physiology by modulating gene expression and signal transduction pathways. However, although the signalling intermediates between nutrient availability and altered gene expression have become increasingly well documented, how eukaryotic cells sense the presence of either a nutritionally rich or deprived medium is still uncertain. From recent studies it appears that the intracellular amino acid pool size is particularly important in regulating translational effectors, thus, regulated transport of amino acids across the plasma membrane represents a means by which the cellular response to amino acids could be controlled. Furthermore, evidence from studies with transportable amino acid analogues has demonstrated that flux through amino acid transporters may act as an initiator of nutritional signalling. This evidence, coupled with the substrate selectivity and sensitivity to nutrient availability classically associated with amino acid transporters, plus the recent discovery of transporter-associated signalling proteins, demonstrates a potential role for nutrient transporters as initiators of cellular nutrient signalling. Here, we review the evidence supporting the idea that distinct amino acid "receptors" function to detect and transmit certain nutrient stimuli in higher eukaryotes. In particular, we focus on the role that amino acid transporters may play in the sensing of amino acid levels, both directly as initiators of nutrient signalling and indirectly as regulators of external amino acid access to intracellular receptor/signalling mechanisms. PMID:12879880

  7. Signaling molecules and pathways regulating the fate of spermatogonial stem cells

    PubMed Central

    He, Zuping; Kokkinaki, Maria; Dym, Martin

    2009-01-01

    Spermatogenesis is the process that involves the division and differentiation of spermatogonial stem cells (SSCs) into mature spermatozoa. SSCs are a subpopulation of type A spermatogonia resting on the basement membrane in the mammalian testis. Self-renewal and differentiation of SSCs are the foundation of normal spermatogenesis, and thus a better understanding of molecular mechanisms and signaling pathways in the SSCs is of paramount importance for the regulation of spermatogenesis and may eventually lead to novel targets for male contraception as well as for gene therapy of male infertility and testicular cancer. Uncovering the molecular mechanisms is also of great interest to a better understanding of SSC aging and for developing novel therapeutic strategies for degenerative diseases in view of the recent work demonstrating the pluripotent potential of the SSC. Progress has recently been made in elucidating the signaling molecules and pathways that determine cell fate decisions of SSCs. In this review, we first address the morphological features, phenotypic characteristics, and the potential of SSCs. And then we focus on the recent advances in defining the key signaling molecules and crucial signaling pathways regulating self-renewal and differentiation of SSCs. The association of aberrant expression of signaling molecules and cascades with abnormal spermatogenesis and testicular cancer are also discussed. Finally we point out potential future directions to pursue in research on signaling pathways of SSCs. PMID:19263492

  8. Activation of cell signaling via optical manipulation of gold-coated liposomes encapsulating signaling molecules

    NASA Astrophysics Data System (ADS)

    Orsinger, Gabriel V.; Leung, Sarah J.; Romanowski, Marek

    2013-02-01

    Many diseases involve changes in cell signaling cascades, as seen commonly in drug resistant cancers. To better understand these intricate signaling events in diseased cells and tissues, experimental methods of probing cellular communication at a single to multi-cell level are required. We recently introduced a general platform for activation of selected signaling pathways by optically controlled delivery and release of water soluble factors using gold-coated liposomes. In the example presented here, we encapsulated inositol trisphosphate (IP3), a ubiquitous intracellular secondary messenger involved in GPCR and Akt signaling cascades, within 100 nm gold-coated liposomes. The high polarizability of the liposome's unique gold pseudo-shell allows stable optical trapping for subcellular manipulation in the presence of cells. We take this optical manipulation further by optically injecting IP3-containing liposomes into the cytosol of a single cell to initiate localized cell signaling. Upon optical injection of liposomal IP3 into a single ovarian carcinoma cell, we observed localized activation as reported by changes in Indo-1 fluorescence intensity. With established gap junctions between the injected cell and neighboring cells, we monitored propagation of this signaling to and through nearby cells.

  9. Enhancement of Raman scattering signal of a few molecules using photonic nanojet mediated SERS technique

    NASA Astrophysics Data System (ADS)

    Das, G. M.; Parit, M. K.; Laha, R.; Dantham, V. R.

    2016-05-01

    Now a days, single molecule surface enhanced Raman spectroscopy (SMSERS) has become a fascinating tool for studying the structural properties, static and dynamic events of single molecules (instead of ensemble average), with the help of efficient plasmonic nanostructures. This is extremely useful in the field of proteomics because the structural properties of protein molecules are heterogeneous. Even though, SMSERS provides wealthy information about single molecules, it demands high quality surface enhanced Raman scattering (SERS) substrates. So far, a very few researchers succeeded in demonstrating the single molecule Raman scattering using conventional SERS technique. However, the experimental S/N of the Raman signal has been found to be very poor. Recently, with the help of photonic nanojet of an optical microsphere, we were able to enhance the SERS signal of a few molecules adsorbed on the SERS substrates (gold symmetric and asymmetric nanodimers and trimers dispersed on a glass slide). Herein, we report a few details about photonic nanojet mediated SERS technique, a few experimental results and a detailed theoretical study on symmetric and asymmetric nanosphere dimers to understand the dependence of localised surface plasmon resonance (LSPR) wavelength of a nanodimer on the nanogap size and polarization of the excitation light.

  10. Effects of bile acids on hepatocellular signaling and secretion.

    PubMed Central

    Beuers, U.

    1997-01-01

    Bile acids modulate hepatocellular signaling pathways in vitro at physiological concentrations. The present paper provides a brief overview of the effects of bile acids on three key messengers in liver cells: cytosolic free calcium, protein kinase A and protein kinase C. PMID:9626754

  11. The roles of bile acids and sphingosine-1-phosphate signaling in the hepatobiliary diseases.

    PubMed

    Nagahashi, Masayuki; Yuza, Kizuki; Hirose, Yuki; Nakajima, Masato; Ramanathan, Rajesh; Hait, Nitai C; Hylemon, Phillip B; Zhou, Huiping; Takabe, Kazuaki; Wakai, Toshifumi

    2016-09-01

    Based on research carried out over the last decade, it has become increasingly evident that bile acids act not only as detergents, but also as important signaling molecules that exert various biological effects via activation of specific nuclear receptors and cell signaling pathways. Bile acids also regulate the expression of numerous genes encoding enzymes and proteins involved in the synthesis and metabolism of bile acids, glucose, fatty acids, and lipoproteins, as well as energy metabolism. Receptors activated by bile acids include, farnesoid X receptor α, pregnane X receptor, vitamin D receptor, and G protein-coupled receptors, TGR5, muscarinic receptor 2, and sphingosine-1-phosphate receptor (S1PR)2. The ligand of S1PR2, sphingosine-1-phosphate (S1P), is a bioactive lipid mediator that regulates various physiological and pathophysiological cellular processes. We have recently reported that conjugated bile acids, via S1PR2, activate and upregulate nuclear sphingosine kinase 2, increase nuclear S1P, and induce genes encoding enzymes and transporters involved in lipid and sterol metabolism in the liver. Here, we discuss the role of bile acids and S1P signaling in the regulation of hepatic lipid metabolism and in hepatobiliary diseases. PMID:27459945

  12. Two 2[5H]-Furanones as Possible Signaling Molecules in Lactobacillus helveticus

    PubMed Central

    Ndagijimana, Maurice; Vallicelli, Melania; Cocconcelli, P. Sandro; Cappa, Fabrizio; Patrignani, Francesca; Lanciotti, Rosalba; Guerzoni, M. Elisabetta

    2006-01-01

    Two 2[5H]-furanones, in association with medium-chain fatty acids, were released in whey by Lactobacillus helveticus exposed to oxidative and heat stresses. This species plays an important role in cheese technology, particularly for Swiss-type cheeses and Grana cheese. Moreover, it significantly contributes to cheese ripening by means of an early autolysis and the release of enzymes during processing. Experimental evidence of the involvement of the two 2[5H]-furanones, detected by a gas chromatography-mass spectrometry/solid-phase microextraction technique, in the autolysis phenomenon has been obtained. Zymograms performed by using renaturing sodium dodecyl sulfate-polyacrylamide gels were used to detect the bioactivity of the supernatants containing the two furanones on fresh cells of the same strain. In addition to bands corresponding to known autolysins, new autolysins were detected concomitant with the exposure of Lactobacillus helveticus to the supernatants, which can be regarded as conditioned media (CM), and to a commercial furanone, 5-ethyl-3-hydroxy-4-methyl-2[5H]-furanone (HEMFi), having spectral data similar to those of the newly described 2[5H]-furanones. Morphological changes were observed when fresh cells were exposed to CM containing the two 2[5H]-furanones and HEMFi. The two furanones produced by Lactobacillus helveticus, which met a number of criteria to be included in cell-cell signaling molecules, have a presumptive molecular mass lower than those of already known 3[2H]-furanones having an autolytic activity and being produced by gram-negative bacteria. Moreover, they present a different chemical structure with respect to the furanones already identified as products of Lactococcus lactis subsp. cremoris or to those identified in some cheeses with Lactobacillus helveticus as a starter culture. PMID:16957229

  13. Kidney injury molecule-1 (KIM-1) mediates renal epithelial cell repair via ERK MAPK signaling pathway

    PubMed Central

    Zhang, Zhiwei; Cai, Cindy X

    2016-01-01

    The expression of kidney injury molecule-1 (KIM-1), a very promising sensitive and specific urinary biomarker for acute renal injury, is markedly upregulated in injured and regenerating renal proximal tubular epithelial cells following ischemic or toxic insults, suggesting a possible role for this molecule in renal repair process. In the present study we report that expression of KIM-1 facilitates renal tubular epithelial cell repair by promoting cell migration and proliferation. KIM-1 expression also enhances ERK MAPK activation, and the modulatory effect of KIM-1 on cellular repair process is likely mediated via ERK MAPK signaling pathway. PMID:27084535

  14. Kidney injury molecule-1 (KIM-1) mediates renal epithelial cell repair via ERK MAPK signaling pathway.

    PubMed

    Zhang, Zhiwei; Cai, Cindy X

    2016-05-01

    The expression of kidney injury molecule-1 (KIM-1), a very promising sensitive and specific urinary biomarker for acute renal injury, is markedly upregulated in injured and regenerating renal proximal tubular epithelial cells following ischemic or toxic insults, suggesting a possible role for this molecule in renal repair process. In the present study, we report that expression of KIM-1 facilitates renal tubular epithelial cell repair by promoting cell migration and proliferation. KIM-1 expression also enhances ERK MAPK activation, and the modulatory effect of KIM-1 on cellular repair process is likely mediated via ERK MAPK signaling pathway. PMID:27084535

  15. Nitro-Fatty Acids in Plant Signaling: Nitro-Linolenic Acid Induces the Molecular Chaperone Network in Arabidopsis.

    PubMed

    Mata-Pérez, Capilla; Sánchez-Calvo, Beatriz; Padilla, María N; Begara-Morales, Juan C; Luque, Francisco; Melguizo, Manuel; Jiménez-Ruiz, Jaime; Fierro-Risco, Jesús; Peñas-Sanjuán, Antonio; Valderrama, Raquel; Corpas, Francisco J; Barroso, Juan B

    2016-02-01

    Nitro-fatty acids (NO2-FAs) are the product of the reaction between reactive nitrogen species derived of nitric oxide (NO) and unsaturated fatty acids. In animal systems, NO2-FAs are considered novel signaling mediators of cell function based on a proven antiinflammatory response. Nevertheless, the interaction of NO with fatty acids in plant systems has scarcely been studied. Here, we examine the endogenous occurrence of nitro-linolenic acid (NO2-Ln) in Arabidopsis and the modulation of NO2-Ln levels throughout this plant's development by mass spectrometry. The observed levels of this NO2-FA at picomolar concentrations suggested its role as a signaling effector of cell function. In fact, 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 heat shock proteins and supporting a conserved mechanism of action in both animal and plant defense processes. Bioinformatics analysis revealed that NO2-Ln was also involved in the response to oxidative stress conditions, mainly depicted by H2O2, reactive oxygen species, and oxygen-containing compound responses, with a high induction of ascorbate peroxidase expression. Closely related to these results, NO2-Ln levels significantly rose under several abiotic-stress conditions such as wounding or exposure to salinity, cadmium, and low temperature, thus validating the outcomes found by RNA-seq technology. Jointly, to our knowledge, these are the first results showing the endogenous presence of NO2-Ln in Arabidopsis (Arabidopsis thaliana) and supporting the strong signaling role of these molecules in the defense mechanism against different abiotic-stress situations. PMID:26628746

  16. Nitro-Fatty Acids in Plant Signaling: Nitro-Linolenic Acid Induces the Molecular Chaperone Network in Arabidopsis1[OPEN

    PubMed Central

    Padilla, María N.; Begara-Morales, Juan C.; Luque, Francisco; Melguizo, Manuel; Fierro-Risco, Jesús; Peñas-Sanjuán, Antonio; Valderrama, Raquel

    2016-01-01

    Nitro-fatty acids (NO2-FAs) are the product of the reaction between reactive nitrogen species derived of nitric oxide (NO) and unsaturated fatty acids. In animal systems, NO2-FAs are considered novel signaling mediators of cell function based on a proven antiinflammatory response. Nevertheless, the interaction of NO with fatty acids in plant systems has scarcely been studied. Here, we examine the endogenous occurrence of nitro-linolenic acid (NO2-Ln) in Arabidopsis and the modulation of NO2-Ln levels throughout this plant’s development by mass spectrometry. The observed levels of this NO2-FA at picomolar concentrations suggested its role as a signaling effector of cell function. In fact, 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 heat shock proteins and supporting a conserved mechanism of action in both animal and plant defense processes. Bioinformatics analysis revealed that NO2-Ln was also involved in the response to oxidative stress conditions, mainly depicted by H2O2, reactive oxygen species, and oxygen-containing compound responses, with a high induction of ascorbate peroxidase expression. Closely related to these results, NO2-Ln levels significantly rose under several abiotic-stress conditions such as wounding or exposure to salinity, cadmium, and low temperature, thus validating the outcomes found by RNA-seq technology. Jointly, to our knowledge, these are the first results showing the endogenous presence of NO2-Ln in Arabidopsis (Arabidopsis thaliana) and supporting the strong signaling role of these molecules in the defense mechanism against different abiotic-stress situations. PMID:26628746

  17. Rhizosphere ecology of lumichrome and riboflavin, two bacterial signal molecules eliciting developmental changes in plants.

    PubMed

    Dakora, Felix D; Matiru, Viviene N; Kanu, Alfred S

    2015-01-01

    Lumichrome and riboflavin are novel molecules from rhizobial exudates that stimulate plant growth. Reported studies have revealed major developmental changes elicited by lumichrome at very low nanomolar concentrations (5 nM) in plants, which include early initiation of trifoliate leaves, expansion of unifoliate and trifoliate leaves, increased stem elongation and leaf area, and consequently greater biomass accumulation in monocots and dicots. But higher lumichrome concentration (50 nM) depressed root development and reduced growth of unifoliate and second trifoliate leaves. While the mechanisms remain unknown, it is possible that lumichrome released by rhizobia induced the biosynthesis of classical phytohormones that caused the observed developmental changes in plants. We also showed in earlier studies that applying either 10 nM lumichrome, 10 nM ABA, or 10 ml of infective rhizobial cells (0.2 OD600) to roots of monocots and dicots for 44 h produced identical effects, which included decreased stomatal conductance and leaf transpiration in Bambara groundnut, soybean, and maize, increased stomatal conductance and transpiration in cowpea and lupin, and elevated root respiration in maize (19% by rhizobia and 20% by lumichrome). Greater extracellular exudation of lumichrome, riboflavin and indole acetic acid by N2-fixing rhizobia over non-fixing bacteria is perceived to be an indication of their role as symbiotic signals. This is evidenced by the increased concentration of lumichrome and riboflavin in the xylem sap of cowpea and soybean plants inoculated with infective rhizobia. In fact, greater xylem concentration of lumichrome in soybean and its correspondingly increased accumulation in leaves was found to result in dramatic developmental changes than in cowpea. Furthermore, lumichrome and riboflavin secreted by soil rhizobia are also known to function as (i) ecological cues for sensing environmental stress, (ii) growth factors for microbes, plants, and humans, (iii

  18. Rhizosphere ecology of lumichrome and riboflavin, two bacterial signal molecules eliciting developmental changes in plants

    PubMed Central

    Dakora, Felix D.; Matiru, Viviene N.; Kanu, Alfred S.

    2015-01-01

    Lumichrome and riboflavin are novel molecules from rhizobial exudates that stimulate plant growth. Reported studies have revealed major developmental changes elicited by lumichrome at very low nanomolar concentrations (5 nM) in plants, which include early initiation of trifoliate leaves, expansion of unifoliate and trifoliate leaves, increased stem elongation and leaf area, and consequently greater biomass accumulation in monocots and dicots. But higher lumichrome concentration (50 nM) depressed root development and reduced growth of unifoliate and second trifoliate leaves. While the mechanisms remain unknown, it is possible that lumichrome released by rhizobia induced the biosynthesis of classical phytohormones that caused the observed developmental changes in plants. We also showed in earlier studies that applying either 10 nM lumichrome, 10 nM ABA, or 10 ml of infective rhizobial cells (0.2 OD600) to roots of monocots and dicots for 44 h produced identical effects, which included decreased stomatal conductance and leaf transpiration in Bambara groundnut, soybean, and maize, increased stomatal conductance and transpiration in cowpea and lupin, and elevated root respiration in maize (19% by rhizobia and 20% by lumichrome). Greater extracellular exudation of lumichrome, riboflavin and indole acetic acid by N2-fixing rhizobia over non-fixing bacteria is perceived to be an indication of their role as symbiotic signals. This is evidenced by the increased concentration of lumichrome and riboflavin in the xylem sap of cowpea and soybean plants inoculated with infective rhizobia. In fact, greater xylem concentration of lumichrome in soybean and its correspondingly increased accumulation in leaves was found to result in dramatic developmental changes than in cowpea. Furthermore, lumichrome and riboflavin secreted by soil rhizobia are also known to function as (i) ecological cues for sensing environmental stress, (ii) growth factors for microbes, plants, and humans, (iii

  19. Paradoxical signaling by a secreted molecule leads to homeostasis of cell levels.

    PubMed

    Hart, Yuval; Reich-Zeliger, Shlomit; Antebi, Yaron E; Zaretsky, Irina; Mayo, Avraham E; Alon, Uri; Friedman, Nir

    2014-08-28

    A widespread feature of extracellular signaling in cell circuits is paradoxical pleiotropy: the same secreted signaling molecule can induce opposite effects in the responding cells. For example, the cytokine IL-2 can promote proliferation and death of T cells. The role of such paradoxical signaling remains unclear. To address this, we studied CD4(+) T cell expansion in culture. We found that cells with a 30-fold difference in initial concentrations reached a homeostatic concentration nearly independent of initial cell levels. Below an initial threshold, cell density decayed to extinction (OFF-state). We show that these dynamics relate to the paradoxical effect of IL-2, which increases the proliferation rate cooperatively and the death rate linearly. Mathematical modeling explained the observed cell and cytokine dynamics and predicted conditions that shifted cell fate from homeostasis to the OFF-state. We suggest that paradoxical signaling provides cell circuits with specific dynamical features that are robust to environmental perturbations. PMID:25171404

  20. Inhibition of Protein-Protein Interactions and Signaling by Small Molecules

    NASA Astrophysics Data System (ADS)

    Freire, Ernesto

    2010-03-01

    Protein-protein interactions are at the core of cell signaling pathways as well as many bacterial and viral infection processes. As such, they define critical targets for drug development against diseases such as cancer, arthritis, obesity, AIDS and many others. Until now, the clinical inhibition of protein-protein interactions and signaling has been accomplished with the use of antibodies or soluble versions of receptor molecules. Small molecule replacements of these therapeutic agents have been extremely difficult to develop; either the necessary potency has been hard to achieve or the expected biological effect has not been obtained. In this presentation, we show that a rigorous thermodynamic approach that combines differential scanning calorimetry (DSC) and isothermal titration calorimetry (ITC) provides a unique platform for the identification and optimization of small molecular weight inhibitors of protein-protein interactions. Recent advances in the development of cell entry inhibitors of HIV-1 using this approach will be discussed.

  1. Caffeine and REM sleep deprivation: Effect on basal levels of signaling molecules in area CA1.

    PubMed

    Alkadhi, Karim A; Alhaider, Ibrahim A

    2016-03-01

    We have investigated the neuroprotective effect of chronic caffeine treatment on basal levels of memory-related signaling molecules in area CA1 of sleep-deprived rats. Animals in the caffeine groups were treated with caffeine in drinking water (0.3g/l) for four weeks before they were REM sleep-deprived for 24h in the Modified Multiple Platforms paradigm. Western blot analysis of basal protein levels of plasticity- and memory-related signaling molecules in hippocampal area CA1 showed significant down regulation of the basal levels of phosphorylated- and total-CaMKII, phosphorylated- and total-CREB as well as those of BDNF and CaMKIV in sleep deprived rats. All these changes were completely prevented in rats that chronically consumed caffeine. The present findings suggest an important neuroprotective property of caffeine in sleep deprivation. PMID:26767416

  2. Saturated fatty-acids regulate retinoic acid signaling and suppress tumorigenesis by targeting fatty-acid-binding protein 5

    PubMed Central

    Levi, Liraz; Wang, Zeneng; Doud, Mary Kathryn; Hazen, Stanley L.; Noy, Noa

    2015-01-01

    Long chain fatty acids (LCFA) serve as energy sources, components of cell membranes, and precursors for signalling molecules. Here we show that these biological compounds also regulate gene expression and that they do so by controlling the transcriptional activities of the retinoic acid (RA)-activated nuclear receptors RAR and PPARβ/δ. The data indicate that these activities of LCFA are mediated by FABP5 which delivers ligands from the cytosol to nuclear PPARβ/δ. Both saturated and unsaturated LCFA (SLCFA, ULCFA) bind to FABP5, thereby displacing RA and diverting it to RAR. However, while SLCFA inhibit, ULCFA activate the FABP5/PPARβ/δ pathway. We show further that, by concomitantly promoting activation of RAR and inhibiting the activation of PPARβ/δ, SLCFA suppress the oncogenic properties of FABP5-expressing carcinoma cells in cultured cells and in vivo. The observations suggest that compounds that inhibit FABP5 may constitute a new class of drugs for therapy of certain types of cancer. PMID:26592976

  3. Saturated fatty acids regulate retinoic acid signalling and suppress tumorigenesis by targeting fatty acid-binding protein 5.

    PubMed

    Levi, Liraz; Wang, Zeneng; Doud, Mary Kathryn; Hazen, Stanley L; Noy, Noa

    2015-01-01

    Long chain fatty acids (LCFA) serve as energy sources, components of cell membranes and precursors for signalling molecules. Here we show that these biological compounds also regulate gene expression and that they do so by controlling the transcriptional activities of the retinoic acid (RA)-activated nuclear receptors RAR and PPARβ/δ. The data indicate that these activities of LCFA are mediated by FABP5, which delivers ligands from the cytosol to nuclear PPARβ/δ. Both saturated and unsaturated LCFA (SLCFA, ULCFA) bind to FABP5, thereby displacing RA and diverting it to RAR. However, while SLCFA inhibit, ULCFA activate the FABP5/PPARβ/δ pathway. We show further that, by concomitantly promoting the activation of RAR and inhibiting the activation of PPARβ/δ, SLCFA suppress the oncogenic properties of FABP5-expressing carcinoma cells in cultured cells and in vivo. The observations suggest that compounds that inhibit FABP5 may constitute a new class of drugs for therapy of certain types of cancer. PMID:26592976

  4. Dissociative attachment reactions of electrons with strong acid molecules

    NASA Astrophysics Data System (ADS)

    Adams, Nigel G.; Smith, David; Viggiano, A. A.; Paulson, John F.; Henchman, Michael J.

    1986-06-01

    Using the flowing afterglow/Langmuir probe (FALP) technique, we have determined (at variously 300 and 570 K) the dissociative attachment coefficients β for the reactions of electrons with the common acids HNO3 (producing NO-2) and H2SO4 (HSO-4), the superacids FSO3H (FSO-3), CF3SO3H (CF3SO-3), ClSO3H (ClSO-3,Cl-), the acid anhydride (CF3SO2)2O (CF3SO-3), and the halogen halides HBr (Br-) and HI (I-). The anions formed in the reactions are those given in the parentheses. The reactions with HF and HCl were investigated, but did not occur at a measurable rate since they are very endothermic. Dissociative attachment is rapid for the common acids, the superacids, and the anhydride, the measured β being appreciable fractions of the theoretical maximum β for such reactions, βmax. The HI reaction is very fast ( β˜βmax) but the HBr reaction occurs much more slowly because it is significantly endothermic. The data indicate that the extreme acidity of the (Bronsted-type) superacids has its equivalence in the very efficient gas-phase dissociative attachment which these species undergo when reacting with free electrons. The anions of the superacids generated in these reactions, notably FSO-3 and CF3SO-3, are very stable (unreactive) implying exceptionally large electron affinities for the FSO3 and CF3SO3 radicals.

  5. 2-Fatty acrylic acids: new highly derivatizable lipophilic platform molecules

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper reports the incorporation of an alpha-methylene unit into fatty acid skeletons. Since the new olefin is conjugated with the carboxylate, it is susceptible to 1,4- (Michael) additions. We have used multifunctional thiols and amines for additions at the methylene. The resulting products ...

  6. Presence of quorum sensing signal molecules in minced beef stored under various temperature and packaging conditions.

    PubMed

    Blana, Vasiliki A; Nychas, George-John E

    2014-03-01

    The presence of acylated homoserine lactones (AHLs) and autoinducer-2 (AI-2)-like activity was observed in meat stored under various temperatures (0, 5, 10 and 15°C) and packaging (air, modified atmospheres and modified atmospheres with oregano essential oil) conditions, and correlated with the ephemeral spoilage organisms that comprise the microbial community generally associated with this product. Quorum sensing signal molecules were found to be affected by the packaging conditions e.g. temperature and atmosphere used for meat preservation as a consequence of the development of a distinct microbial community. AHL signal molecules were detected at all incubation temperatures in minced beef samples, both stored aerobically and under modified atmospheres, when both pseudomonads and Enterobacteriaceae populations ranged from 10(7) to 10(9)CFU/g, but no signal molecules were detected in minced beef stored under modified atmospheres in the presence of volatile compounds of oregano essential oil, where both these groups failed to grow in high numbers. Additionally, no significant AI-2 activity was observed in the tested cell-free meat extracts (CFME), regardless of the indigenous bacterial populations. The presence of N-(β-ketocaproyl)-homoserine lactone was confirmed with TLC analysis of CFME. PMID:24380750

  7. Electric Dipole Moments of Nanosolvated Acid Molecules in Water Clusters

    NASA Astrophysics Data System (ADS)

    Guggemos, Nicholas; Slavíček, Petr; Kresin, Vitaly V.

    2015-01-01

    The electric dipole moments of (H2O)nDCl (n =3 - 9 ) clusters have been measured by the beam-deflection method. Reflecting the (dynamical) charge distribution within the system, the dipole moment contributes information about the microscopic structure of nanoscale solvation. The addition of a DCl molecule to a water cluster results in a strongly enhanced susceptibility. There is evidence for a noticeable rise in the dipole moment occurring at n ≈5 - 6 . This size is consistent with predictions for the onset of ionic dissociation. Additionally, a molecular-dynamics model suggests that even with a nominally bound impurity an enhanced dipole moment can arise due to the thermal and zero-point motion of the proton and the water molecules. The experimental measurements and the calculations draw attention to the importance of fluctuations in defining the polarity of water-based nanoclusters and generally to the essential role played by motional effects in determining the response of fluxional nanoscale systems under realistic conditions.

  8. Stardust and the Molecules of Life (Why are the Amino Acids Left-Handed?)

    SciTech Connect

    Boyd, R N; Kajino, T; Onaka, T

    2010-04-02

    A mechanism for creating and selecting amino acid chirality is identified, and subsequent chemical replication and galactic mixing that would populate the galaxy with the predominant species will be described. This involves: (1) the spin of the {sup 14}N in the amino acids, or in precursor molecules from which amino acids might be formed, coupling to the chirality of the molecules; (2) the neutrinos emitted from the supernova, together with magnetic field from the nascent neutron star or black hole from the supernova selectively destroying one orientation of the {sup 14}N, thereby selecting the chirality associated with the other {sup 14}N orientation; (3) amplification by chemical evolution, by which the molecules replicate on a relatively short timescale; and (4) galactic mixing on a longer timescale mixing the selected molecules throughout the galaxy.

  9. Surface functionalization of bioactive glasses with natural molecules of biological significance, Part I: Gallic acid as model molecule

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Ferraris, Sara; Prenesti, Enrico; Verné, Enrica

    2013-12-01

    Gallic acid (3,4,5-trihydroxybenzoic acid, GA) and its derivatives are a group of biomolecules (polyphenols) obtained from plants. They have effects which are potentially beneficial to heath, for example they are antioxidant, anticarcinogenic and antibacterial, as recently investigated in many fields such as medicine, food and plant sciences. The main drawbacks of these molecules are both low stability and bioavailability. In this research work the opportunity to graft GA to bioactive glasses is investigated, in order to deliver the undamaged biological molecule into the body, using the biomaterial surfaces as a localized carrier. GA was considered for functionalization since it is a good model molecule for polyphenols and presents several interesting biological activities, like antibacterial, antioxidant and anticarcinogenic properties. Two different silica based bioactive glasses (SCNA and CEL2), with different reactivity, were employed as substrates. UV photometry combined with the Folin&Ciocalteu reagent was adopted to test the concentration of GA in uptake solution after functionalization. This test verified how much GA consumption occurred with surface modification and it was also used on solid samples to test the presence of GA on functionalized glasses. XPS and SEM-EDS techniques were employed to characterize the modification of material surface properties and functional group composition before and after functionalization.

  10. Discovery of Novel Small Molecule Activators of β-Catenin Signaling

    PubMed Central

    Verkaar, Folkert; van der Stelt, Mario; Blankesteijn, W. Matthijs; van der Doelen, Antoon A.; Zaman, Guido J. R.

    2011-01-01

    Wnt/β-catenin signaling plays a major role in embryonic development and adult stem cell maintenance. Reduced activation of the Wnt/β-catenin pathway underlies neurodegenerative disorders and aberrations in bone formation. Screening of a small molecule compound library with a β-galactosidase fragment complementation assay measuring β-catenin nuclear entry revealed bona fide activators of β-catenin signaling. The compounds stabilized cytoplasmic β-catenin and activated β–catenin-dependent reporter gene activity. Although the mechanism through which the compounds activate β-catenin signaling has yet to be determined, several key regulators of Wnt/β-catenin signaling, including glycogen synthase kinase 3 and Frizzled receptors, were excluded as the molecular target. The compounds displayed remarkable selectivity, as they only induced β-catenin signaling in a human osteosarcoma U2OS cell line and not in a variety of other cell lines examined. Our data indicate that differences in cellular Wnt/β-catenin signaling machinery can be exploited to identify cell type-specific activators of Wnt/β-catenin signaling. PMID:21559429

  11. Dissection of the cis-2-decenoic acid signaling network in Pseudomonas aeruginosa using microarray technique

    PubMed Central

    Rahmani-Badi, Azadeh; Sepehr, Shayesteh; Fallahi, Hossein; Heidari-Keshel, Saeed

    2015-01-01

    Many bacterial pathogens use quorum-sensing (QS) signaling to regulate the expression of factors contributing to virulence and persistence. Bacteria produce signals of different chemical classes. The signal molecule, known as diffusible signal factor (DSF), is a cis-unsaturated fatty acid that was first described in the plant pathogen Xanthomonas campestris. Previous works have shown that human pathogen, Pseudomonas aeruginosa, also synthesizes a structurally related molecule, characterized as cis-2-decenoic acid (C10: Δ2, CDA) that induces biofilm dispersal by multiple types of bacteria. Furthermore, CDA has been shown to be involved in inter-kingdom signaling that modulates fungal behavior. Therefore, an understanding of its signaling mechanism could suggest strategies for interference, with consequences for disease control. To identify the components of CDA signaling pathway in this pathogen, a comparative transcritpome analysis was conducted, in the presence and absence of CDA. A protein-protein interaction (PPI) network for differentially expressed (DE) genes with known function was then constructed by STRING and Cytoscape. In addition, the effects of CDA in combination with antimicrobial agents on the biofilm surface area and bacteria viability were evaluated using fluorescence microscopy and digital image analysis. Microarray analysis identified 666 differentially expressed genes in the presence of CDA and gene ontology (GO) analysis revealed that in P. aeruginosa, CDA mediates dispersion of biofilms through signaling pathways, including enhanced motility, metabolic activity, virulence as well as persistence at different temperatures. PPI data suggested that a cluster of five genes (PA4978, PA4979, PA4980, PA4982, PA4983) is involved in the CDA synthesis and perception. Combined treatments using both CDA and antimicrobial agents showed that following exposure of the biofilms to CDA, remaining cells on the surface were easily removed and killed by

  12. Analysis of single nucleic acid molecules in micro- and nano-fluidics.

    PubMed

    Friedrich, Sarah M; Zec, Helena C; Wang, Tza-Huei

    2016-03-01

    Nucleic acid analysis has enhanced our understanding of biological processes and disease progression, elucidated the association of genetic variants and disease, and led to the design and implementation of new treatment strategies. These diverse applications require analysis of a variety of characteristics of nucleic acid molecules: size or length, detection or quantification of specific sequences, mapping of the general sequence structure, full sequence identification, analysis of epigenetic modifications, and observation of interactions between nucleic acids and other biomolecules. Strategies that can detect rare or transient species, characterize population distributions, and analyze small sample volumes enable the collection of richer data from biosamples. Platforms that integrate micro- and nano-fluidic operations with high sensitivity single molecule detection facilitate manipulation and detection of individual nucleic acid molecules. In this review, we will highlight important milestones and recent advances in single molecule nucleic acid analysis in micro- and nano-fluidic platforms. We focus on assessment modalities for single nucleic acid molecules and highlight the role of micro- and nano-structures and fluidic manipulation. We will also briefly discuss future directions and the current limitations and obstacles impeding even faster progress toward these goals. PMID:26818700

  13. Activation of Carbonyl-Containing Molecules with Solid Lewis Acids in Aqueous Media

    SciTech Connect

    Román-Leshkov, Yuriy; Davis, Mark E.

    2011-09-28

    Current interest in reacting carbonyl-containing molecules in aqueous media is primarily due to the growing emphasis on conversion of biomass to fuels and chemicals. Recently, solid Lewis acids have been shown to perform catalytic reactions with carbonyl-containing molecules such as sugars in aqueous media. Here, catalysis mediated by Lewis acids is briefly discussed, Lewis acid solids that perform catalysis in aqueous media are then described, and the review is concluded with a few comments on the outlook for the future.

  14. Specific spin-labeling of transfer ribonucleic acid molecules.

    PubMed Central

    Caron, M; Dugas, H

    1976-01-01

    The spin labels anhydride (ASL), bromoacetamide (BSL) and carbodiimide (CSL) were used to label selectively tRNAGlu, tRNA fMet and tRNAPhe from E. coli. The preparation and characterization of the sites of labeling of eight new spin-labeled tRNAs are described. The sites of labeling are: s2U using ASL, BSL and CLS and tRNAGlu; s4U using ASL and BSL on tRNAfMet and tRNAPhe; U-37 with CSL on tRNfMet; U-33 with CSL on tRNAPhe. The rare base X at position 47 of tRNAPhe has been acylated with a spin-labeled N-hydroxysuccinimide (HSL). The 3'end of unfractionated tRNA molecules has been chemically modified to a morpholino spin-labeled analogue (MSL). Their respective e.s.r. spectra are reported and discussed. PMID:175353

  15. The function of hydrogen sulphide in iron availability: Sulfur nutrient or signaling molecule?

    PubMed

    Chen, Juan; Shangguan, Zhou-Ping; Zheng, Hai-Lei

    2016-06-01

    Hydrogen sulphide (H2S) has traditionally been considered as a phytotoxin, having deleterious effects on the plant growth and survival. Recently, it was recongnized as a potential signaling molecule involving in physiological regulation similar to nitric oxide (NO) and carbon monoxide (CO) in plants. In a recent study, we mainly focused on the signaling function of H2S in improving adaptation of Zea mays seedlings to iron deficiency. We reported that H2S was closely related to iron uptake, transport, and accumulation, and consequently increased chlorophyll biosynthesis, chloroplast development, and photosynthesis in Z. mays seedlings. Here, we provide more commentary on the signaling roles of H2S in coping with Fe deficiency in plants through increasing sulfur containing metabolites and regulating the expression level of iron homeostasis and sulfur metabolism-related genes in maize seedlings. PMID:26906467

  16. Bile acid promotes liver regeneration via farnesoid X receptor signaling pathways in rats.

    PubMed

    Ding, Long; Yang, Yu; Qu, Yikun; Yang, Ting; Wang, Kaifeng; Liu, Weixin; Xia, Weibin

    2015-06-01

    Bile acids, which are synthesized from cholesterol in the hepatocytes of the liver, are amphipathic molecules with a steroid backbone. Studies have shown that bile acid exhibits important effects on liver regeneration. However, the mechanism underlying these effects remains unclear. The aim of the present study was to investigate the effect of bile acid and the farnesoid X receptor (FXR) on hepatic regeneration and lipid metabolism. Rats were fed with 0.2% bile acid or glucose for 7 days and then subjected to a 50 or 70% hepatectomy. Hepatic regeneration rate, serum and liver levels of bile acid, and expression of FXR and Caveolin‑1, were detected at 24, 48 or 72 h following hepatectomy. The expression of proliferating cell nuclear antigen (PCNA) in the liver was measured using immunohistochemistry at the end of the study. Hepatocytes isolated from rats were treated with bile acid, glucose, FXR agonist and FXR antagonist, separately or in combination. Lipid metabolism, the expression of members of the FXR signaling pathway and energy metabolism‑related factors were measured using ELISA kits or western blotting. Bile acid significantly increased the hepatic regeneration rate and the expression of FXR, Caveolin‑1 and PCNA. Levels of total cholesterol and high density lipoprotein were increased in bile acid‑ or FXR agonist‑treated hepatocytes in vitro. Levels of triglyceride, low density lipoprotein and free fatty acid were decreased. In addition, bile acid and FXR agonists increased the expression of bile salt export pump and small heterodimer partner, and downregulated the expression of apical sodium‑dependent bile acid transporter, Na+/taurocholate cotransporting polypeptide and cholesterol 7α‑hydroxylase. These results suggested that physiological concentrations of bile acid may promote liver regeneration via FXR signaling pathways, and may be associated with energy metabolism. PMID:25634785

  17. Identification and characterization of a small-molecule inhibitor of Wnt signaling in glioblastoma cells.

    PubMed

    De Robertis, Alessandra; Valensin, Silvia; Rossi, Marco; Tunici, Patrizia; Verani, Margherita; De Rosa, Antonella; Giordano, Cinzia; Varrone, Maurizio; Nencini, Arianna; Pratelli, Carmela; Benicchi, Tiziana; Bakker, Annette; Hill, Jeffrey; Sangthongpitag, Kanda; Pendharkar, Vishal; Liu, Boping; Ng, Fui Mee; Then, Siew Wen; Jing Tai, Shi; Cheong, Seong-Moon; He, Xi; Caricasole, Andrea; Salerno, Massimiliano

    2013-07-01

    Glioblastoma multiforme (GBM) is the most common and prognostically unfavorable form of brain tumor. The aggressive and highly invasive phenotype of these tumors makes them among the most anatomically damaging human cancers with a median survival of less than 1 year. Although canonical Wnt pathway activation in cancers has been historically linked to the presence of mutations involving key components of the pathway (APC, β-catenin, or Axin proteins), an increasing number of studies suggest that elevated Wnt signaling in GBM is initiated by several alternative mechanisms that are involved in different steps of the disease. Therefore, inhibition of Wnt signaling may represent a therapeutically relevant approach for GBM treatment. After the selection of a GBM cell model responsive to Wnt inhibition, we set out to develop a screening approach for the identification of compounds capable of modulating canonical Wnt signaling and associated proliferative responses in GBM cells. Here, we show that the small molecule SEN461 inhibits the canonical Wnt signaling pathway in GBM cells, with relevant effects at both molecular and phenotypic levels in vitro and in vivo. These include SEN461-induced Axin stabilization, increased β-catenin phosphorylation/degradation, and inhibition of anchorage-independent growth of human GBM cell lines and patient-derived primary tumor cells in vitro. Moreover, in vivo administration of SEN461 antagonized Wnt signaling in Xenopus embryos and reduced tumor growth in a GBM xenograft model. These data represent the first demonstration that small-molecule-mediated inhibition of Wnt signaling may be a potential approach for GBM therapeutics. PMID:23619303

  18. Identification and characterization of a small molecule inhibitor of WNT signaling in glioblastoma cells

    PubMed Central

    De Robertis, Alessandra; Valensin, Silvia; Rossi, Marco; Tunici, Patrizia; Verani, Margherita; De Rosa, Antonella; Giordano, Cinzia; Varrone, Maurizio; Nencini, Arianna; Pratelli, Carmela; Benicchi, Tiziana; Bakker, Annette; Hill, Jeffrey; Sangthongpitag, Kanda; Pendharkar, Vishal; Boping, Liu; Mee, Ng Fui; Wen, Then Siew; Jing, Tai Shi; Cheong, Seong-Moon; He, Xi; Caricasole, Andrea; Salerno, Massimiliano

    2013-01-01

    Glioblastoma multiforme (GBM) is the most common and prognostically unfavorable form of brain tumor. The aggressive and highly invasive phenotype of these tumors makes them among the most anatomically damaging human cancers with a median survival of less than one year. Although canonical WNT pathway activation in cancers has been historically linked to the presence of mutations involving key components of the pathway (APC, β-CATENIN or AXIN proteins), an increasing number of studies suggest that elevated WNT signaling in GBM is initiated by several alternative mechanisms that are involved in different steps of the disease. Therefore, inhibition of WNT signaling may represent a therapeutically relevant approach for GBM treatment. After the selection of a GBM cell model responsive to WNT inhibition, we set out to develop a screening approach for the identification of compounds capable of modulating canonical WNT signaling and associated proliferative responses in GBM cells. Here we show that the small molecule SEN461 inhibits the canonical WNT signaling pathway in GBM cells, with relevant effects at both molecular and phenotypic levels in vitro and in vivo. These include SEN461-induced AXIN stabilization, increased β-CATENIN phosphorylation/degradation, and inhibition of anchorage-independent growth of human GBM cell lines and patient-derived primary tumor cells in vitro. Moreover, in vivo administration of SEN461 antagonized WNT signaling in Xenopus embryos and reduced tumor growth in a GBM xenograft model. These data represent the first demonstration that small molecule-mediated inhibition of WNT signaling may be a potential approach for GBM therapeutics. PMID:23619303

  19. Optical nanosensor architecture for cell-signaling molecules using DNA aptamer-coated carbon nanotubes.

    PubMed

    Cha, Tae-Gon; Baker, Benjamin A; Sauffer, M Dane; Salgado, Janette; Jaroch, David; Rickus, Jenna L; Porterfield, D Marshall; Choi, Jong Hyun

    2011-05-24

    We report a novel optical biosensor platform using near-infrared fluorescent single-walled carbon nanotubes (SWNTs) functionalized with target-recognizing aptamer DNA for noninvasively detecting cell-signaling molecules in real time. Photoluminescence (PL) emission of aptamer-coated SWNTs is modulated upon selectively binding to target molecules, which is exploited to detect insulin using an insulin-binding aptamer (IBA) as a molecular recognition element. We find that nanotube PL quenches upon insulin recognition via a photoinduced charge transfer mechanism with a quenching rate of k(q) = 5.85 × 10(14) M(-1) s(-1) and a diffusion-reaction rate of k(r) = 0.129 s(-1). Circular dichroism spectra reveal for the first time that IBA strands retain a four-stranded, parallel guanine quadruplex conformation on the nanotubes, ensuring target selectivity. We demonstrate that these IBA-functionalized SWNT sensors incorporated in a collagen extracellular matrix (ECM) can be regenerated by removing bound analytes through enzymatic proteolysis. As proof-of-concept, we show that the SWNT sensors embedded in the ECM promptly detect insulin secreted by cultured pancreatic INS-1 cells stimulated by glucose influx and report a gradient contour of insulin secretion profile. This novel design enables new types of label-free assays and noninvasive, in situ, real-time detection schemes for cell-signaling molecules. PMID:21520951

  20. Label-free electrochemical lead (II) aptasensor using thionine as the signaling molecule and graphene as signal-enhancing platform.

    PubMed

    Gao, Feng; Gao, Cai; He, Suyu; Wang, Qingxiang; Wu, Aiqun

    2016-07-15

    A label-free and highly sensitive electrochemical aptasensor for Pb(2+) was constructed using thionine (TH) as the signaling molecule and graphene (GR) as the signal-enhancing platform. The electrochemical sensing interface was fabricated by stepwise assembly of GR and TH on the lead (II) specific aptamer (LSA) modified electrode. Upon interaction with Pb(2+), the aptamer probe on the sensor underwent conformational switch from a single-stranded DNA form to the G-quadruplex structure, causing the GR with assembled TH released from the electrode surface into solution. As a result, the electrochemical signal of TH on the aptasensor was substantially reduced. Under the optimal experimental conditions, the attenuation of peak currents presented a good linear relationship with the logarithm of Pb(2+) concentrations over the range from 1.6×10(-13) to 1.6×10(-10)M. The detection limit was estimated to be 3.2×10(-14)M. The aptasensor also exhibited good regenerability, excellent selectivity, and acceptable reproducibility, indicating promising application in environment monitoring of lead. PMID:26913503

  1. Jasmonic acid is involved in the signaling pathway for fungal endophyte-induced volatile oil accumulation of Atractylodes lancea plantlets

    PubMed Central

    2012-01-01

    Background Jasmonic acid (JA) is a well-characterized signaling molecule in plant defense responses. However, its relationships with other signal molecules in secondary metabolite production induced by endophytic fungus are largely unknown. Atractylodes lancea (Asteraceae) is a traditional Chinese medicinal plant that produces antimicrobial volatiles oils. We incubated plantlets of A. lancea with the fungus Gilmaniella sp. AL12. to research how JA interacted with other signal molecules in volatile oil production. Results Fungal inoculation increased JA generation and volatile oil accumulation. To investigate whether JA is required for volatile oil production, plantlets were treated with JA inhibitors ibuprofen (IBU) and nordihydroguaiaretic acid. The inhibitors suppressed both JA and volatile oil production, but fungal inoculation could still induce volatile oils. Plantlets were further treated with the nitric oxide (NO)-specific scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt (cPTIO), the H2O2 inhibitors diphenylene iodonium (DPI) and catalase (CAT), and the salicylic acid (SA) biosynthesis inhibitors paclobutrazol and 2-aminoindan-2-phosphonic acid. With fungal inoculation, IBU did not inhibit NO production, and JA generation was significantly suppressed by cPTIO, showing that JA may act as a downstream signal of the NO pathway. Exogenous H2O2 could reverse the inhibitory effects of cPTIO on JA generation, indicating that NO mediates JA induction by the fungus through H2O2-dependent pathways. With fungal inoculation, the H2O2 scavenger DPI/CAT could inhibit JA generation, but IBU could not inhibit H2O2 production, implying that H2O2 directly mediated JA generation. Finally, JA generation was enhanced when SA production was suppressed, and vice versa. Conclusions Jasmonic acid acts as a downstream signaling molecule in NO- and H2O2-mediated volatile oil accumulation induced by endophytic fungus and has a complementary

  2. Single-molecule pull-down for investigating protein-nucleic acid interactions.

    PubMed

    Fareh, Mohamed; Loeff, Luuk; Szczepaniak, Malwina; Haagsma, Anna C; Yeom, Kyu-Hyeon; Joo, Chirlmin

    2016-08-01

    The genome and transcriptome are constantly modified by proteins in the cell. Recent advances in single-molecule techniques allow for high spatial and temporal observations of these interactions between proteins and nucleic acids. However, due to the difficulty of obtaining functional protein complexes, it remains challenging to study the interactions between macromolecular protein complexes and nucleic acids. Here, we combined single-molecule fluorescence with various protein complex pull-down techniques to determine the function and stoichiometry of ribonucleoprotein complexes. Through the use of three examples of protein complexes from eukaryotic cells (Drosha, Dicer, and TUT4 protein complexes), we provide step-by-step guidance for using novel single-molecule techniques. Our single-molecule methods provide sub-second and nanometer resolution and can be applied to other nucleoprotein complexes that are essential for cellular processes. PMID:27017911

  3. Carbon Monoxide, Hydrogen Sulfide, and Nitric Oxide as Signaling Molecules in the Gastrointestinal Tract

    PubMed Central

    Farrugia, Gianrico; Szurszewski, Joseph H.

    2014-01-01

    Carbon monoxide (CO) and hydrogen sulfide (H2S) used to be thought of simply as lethal and (for H2S) smelly gaseous molecules; now they are known to have important signaling functions in the gastrointestinal tract. CO and H2S, which are produced in the gastrointestinal tract by different enzymes, regulate smooth muscle membrane potential and tone, transmit signals from enteric nerves and can regulate the immune system. The pathways that produce nitric oxide (NO) H2S and CO interact—each can inhibit and potentiate the level and activity of the other. However, there are significant differences between these molecules, such as in half-lives; CO is more stable and therefore able to have effects distal to the site of production, whereas NO and H2S are short lived and act only close to sites of production. We review their signaling functions in the luminal gastrointestinal tract and discuss how their pathways interact. We also describe other physiologic functions of CO and H2S and how they might be used as therapeutic agents. PMID:24798417

  4. Characterization of signaling function and expression of HLA class I molecules in medulloblastoma

    PubMed Central

    Smith, Courtney; Santi, Mariarita; Rushing, Elisabeth J.; Cornelison, Robert; MacDonald, Tobey J.

    2011-01-01

    Although known for the important function in the immune system, MHC class I molecules are increasingly ascribed an alternative role in modifying signal transduction. In medulloblastoma, HLA class I molecules are associated with poor prognosis, and can induce ERK1/2 activation upon engagement with ligands that bind to incompletely assembled complexes (so called open conformers). We here demonstrate that ERK1/2 activation in medulloblastoma can occur in the absence of endogenously synthesized β2m, formally excluding involvement of closed HLA class conformation. In addition, several experimental observations suggest that heterogeneity of HLA class I expression may be a reflection of the status of original cells before transformation, rather than a consequence of immune-based selection of HLA-loss mutants. These results contribute to our understanding of an immune system-independent role of HLA class I in the pathology of medulloblastoma, and cancer in general. PMID:20811766

  5. Characterization of signaling function and expression of HLA class I molecules in medulloblastoma.

    PubMed

    Smith, Courtney; Santi, Mariarita; Rushing, Elisabeth J; Cornelison, Robert; MacDonald, Tobey J; Vukmanovic, Stanislav

    2011-06-01

    Although known for the important function in the immune system, MHC class I molecules are increasingly ascribed an alternative role in modifying signal transduction. In medulloblastoma, HLA class I molecules are associated with poor prognosis, and can induce ERK1/2 activation upon engagement with ligands that bind to incompletely assembled complexes (so called open conformers). We here demonstrate that ERK1/2 activation in medulloblastoma can occur in the absence of endogenously synthesized β2m, formally excluding involvement of closed HLA class conformation. In addition, several experimental observations suggest that heterogeneity of HLA class I expression may be a reflection of the status of original cells before transformation, rather than a consequence of immune-based selection of HLA-loss mutants. These results contribute to our understanding of an immune system-independent role of HLA class I in the pathology of medulloblastoma, and cancer in general. PMID:20811766

  6. Increased expression of FGF1-mediated signaling molecules in adipose tissue of obese mice.

    PubMed

    Choi, Youngshim; Jang, Suhyeon; Choi, Myung-Sook; Ryoo, Zae Young; Park, Taesun

    2016-06-01

    Fibroblast growth factors (FGFs) are pleiotropic growth factors that control cell proliferation, migration, and differentiation. Herein, we evaluated whether visceral adiposity of mice is accompanied by the alteration of signaling molecules mediated by fibroblast growth factor receptor 1 (FGFR1) induced by using two different male C57BL/6J mice models of obesity namely high-fat diet (HFD)-induced obesity for 12 weeks or mice with genetic deletion of leptin (ob/ob). Both HFD-fed and ob/ob mice exhibited significantly higher messenger RNA (mRNA) levels of FGF1, cyclin D (cycD), transcription factor E2F1, peroxisome proliferator-activated receptor-gamma 2 (PPAR-γ2), CCAAT-enhancer-binding protein alpha (C/EBPα), and adipocyte protein 2 (aP2) genes in their epididymal adipose tissues compared to those of the normal diet (ND)-fed and lean control mice, respectively. In addition, immunoblot analyses of the epididymal adipose tissues revealed that both mice exposed to HFD and ob/ob mice exhibited elevated phosphorylation of FGFR1, extracellular-signal-regulated kinase (ERK), and retinoblastoma (Rb) proteins. These data support the notion that FGF1-mediated signaling represents an important signaling cascade related to adipogenesis, at least partially, among other known signaling pathways. These new findings regarding the molecular mechanisms controlling adipose tissue plasticity provide a novel insight about the functional network with potential therapeutic application against obesity. PMID:26847131

  7. Focal Activation of Cells by Plasmon Resonance Assisted Optical Injection of Signaling Molecules

    PubMed Central

    2015-01-01

    Experimental methods for single cell intracellular delivery are essential for probing cell signaling dynamics within complex cellular networks, such as those making up the tumor microenvironment. Here, we show a quantitative and general method of interrogation of signaling pathways. We applied highly focused near-infrared laser light to optically inject gold-coated liposomes encapsulating bioactive molecules into single cells for focal activation of cell signaling. For this demonstration, we encapsulated either inositol trisphosphate (IP3), an endogenous cell signaling second messenger, or adenophostin A (AdA), a potent analogue of IP, within 100 nm gold-coated liposomes, and injected these gold-coated liposomes and their contents into the cytosol of single ovarian carcinoma cells to initiate calcium (Ca2+) release from intracellular stores. Upon optical injection of IP3 or AdA at doses above the activation threshold, we observed increases in cytosolic Ca2+ concentration within the injected cell initiating the propagation of a Ca2+ wave throughout nearby cells. As confirmed by octanol-induced inhibition, the intercellular Ca2+ wave traveled via gap junctions. Optical injection of gold-coated liposomes represents a quantitative method of focal activation of signaling cascades of broad interest in biomedical research. PMID:24877558

  8. IL-33 enhances retinoic acid signaling on CD4+ T cells.

    PubMed

    Gajardo, Tania; Pérez, Francisco; Terraza, Claudia; Campos-Mora, Mauricio; Noelle, Randolph J; Pino-Lagos, Karina

    2016-09-01

    Several molecules have been described as CD4+ T cells differentiation modulators and among them retinoic acid (RA) and more recently, IL-33, have been studied. Due to the similarities in T helper cell skewing properties between RA and IL-33, we asked whether IL-33 intersects, directly or indirectly, the RA signaling pathway. Total CD4+ T cells from DR5-luciferase mice were activated in the presence of RA with or without IL-33, and RA signaling was visualized using ex vivo imaging. Our results demonstrate that IL-33 itself is able to trigger RA signaling on CD4+ T cells, which is highly increased when IL-33 is added in conjunction with RA. This study presents IL-33 as a potential player that may synergize with RA in controlling T cell differentiation, and suggests that IL-33 may be an attractive target in controlling T cell differentiation in vivo. PMID:27322964

  9. Comparative Study on Single-Molecule Junctions of Alkane- and Benzene-Based Molecules with Carboxylic Acid/Aldehyde as the Anchoring Groups.

    PubMed

    Chen, Fang; Peng, Lin-Lu; Hong, Ze-Wen; Mao, Jin-Chuan; Zheng, Ju-Fang; Shao, Yong; Niu, Zhen-Jiang; Zhou, Xiao-Shun

    2016-12-01

    We have measured the alkane and benzene-based molecules with aldehyde and carboxylic acid as anchoring groups by using the electrochemical jump-to-contact scanning tunneling microscopy break junction (ECSTM-BJ) approach. The results show that molecule with benzene backbone has better peak shape and intensity than those with alkane backbone. Typically, high junction formation probability for same anchoring group (aldehyde and carboxylic acid) with benzene backbone is found, which contributes to the stronger attractive interaction between Cu and molecules with benzene backbone. The present work shows the import role of backbone in junction, which can guide the design molecule to form effective junction for studying molecular electronics. PMID:27566686

  10. Distribution of proton dissociation constants for model humic and fulvic acid molecules.

    PubMed

    Atalay, Yasemin B; Carbonaro, Richard F; Di Toro, Dominic M

    2009-05-15

    The intrinsic proton binding constants of 10 model humic acid and six model fulvic acid molecules are calculated using SPARC Performs Automated Reasoning in Chemistry (SPARC). The accuracy of the SPARC calculations is examined using estimated microscopic binding constants of various small organic acids. An equimolar mixture of the appropriate hypothetical molecules is used as a representation of soil and aqueous humic acid and fulvic acid. The probability distributions of the mixture microscopic proton binding constants and the intrinsic proton binding constants in the metal speciation models WHAM V and WHAM VI (Windermere humic aqueous models) are compared. The idea is to assess the predictive value of the molecular mixture models as representations of heterogeneous natural organic matter. For aqueous humic and fulvic acids, the results are comparable to the WHAM distribution. For soil humic acid, the WHAM probability distribution is less acidic for the carboxylic sites but similar to that of the phenolic sites. Computations made using the WHAM molecular distributions and WHAM VI are comparable to titration data for Suwannee River fulvic acid. These results suggest that mixture molecular models can be used to investigate and predict the binding of metal cations to humic and fulvic acids. PMID:19544864

  11. Time-dependent study of single-molecule SERS signal from yeast cytochrome c

    NASA Astrophysics Data System (ADS)

    Delfino, Ines; Bizzarri, Anna Rita; Cannistraro, Salvatore

    2006-08-01

    A study of cytochrome c from Saccharomyces cerevisiae adsorbed on silver colloids at very low concentration is carried out by surface-enhanced Raman scattering. Spectra acquired at different times exhibit dramatic fluctuations in both line frequency and intensity indicating that single molecule detection is approached. The intensity fluctuations are investigated by means of a second order time correlation analysis. Such an approach has allowed us to put into evidence the presence of two distinct dynamical phenomena. The results are discussed in connection with diffusion processes to which the protein undergoes with respect to the surface of the Ag nanoclusters and with a modulation of the enhancement of the Raman signal.

  12. The octadecanoic pathway: signal molecules for the regulation of secondary pathways.

    PubMed Central

    Blechert, S; Brodschelm, W; Hölder, S; Kammerer, L; Kutchan, T M; Mueller, M J; Xia, Z Q; Zenk, M H

    1995-01-01

    Plant defense against microbial pathogens and herbivores relies heavily on the induction of defense proteins and low molecular weight antibiotics. The signals between perception of the aggression, gene activation, and the subsequent biosynthesis of secondary compounds are assumed to be pentacylic oxylipin derivatives. The rapid, but transient, synthesis of cis-jasmonic acid was demonstrated after insect attack on a food plant and by microbial elicitor addition to plant suspension cultures. This effect is highly specific and not caused by a number of environmental stresses such as light, heavy metals, or cold or heat shock. Elicitation of Eschscholtzia cell cultures also led to a rapid alkalinization of the growth medium prior to jasmonate formation. Inhibition of this alkalinization process by the protein kinase inhibitor staurosporine also inhibited jasmonate formation. The induction of specific enzymes in the benzo[c]phenanthridine alkaloid pathway leading to the antimicrobial sanguinarine was induced to a qualitatively and quantitatively similar extent by fungal elicitor, methyl jasmonate, and its linolenic acid-derived precursor 12-oxophytodienoic acid. It is herein proposed that a second oxylipid cascade may exist in plants starting from linoleic acid via 15,16-dihydro-12-oxophytodienoic acid to 9,10-dihydrojasmonate. Experiments with synthetic trihomojasmonate demonstrated that beta-oxidation is not a prerequisite for biological activity and that 12-oxophytodienoic acid and derivatives are most likely fully active as signal transducers. Octadecanoic acid-derived compounds are essential elements in modulating the synthesis of antibiotic compounds and are thus integral to plant defense. Images Fig. 4 Fig. 9 PMID:7753776

  13. Reactive oxygen species are involved in gibberellin/abscisic acid signaling in barley aleurone cells.

    PubMed

    Ishibashi, Yushi; Tawaratsumida, Tomoya; Kondo, Koji; Kasa, Shinsuke; Sakamoto, Masatsugu; Aoki, Nozomi; Zheng, Shao-Hui; Yuasa, Takashi; Iwaya-Inoue, Mari

    2012-04-01

    Reactive oxygen species (ROS) act as signal molecules for a variety of processes in plants. However, many questions about the roles of ROS in plants remain to be clarified. Here, we report the role of ROS in gibberellin (GA) and abscisic acid (ABA) signaling in barley (Hordeum vulgare) aleurone cells. The production of hydrogen peroxide (H2O2), a type of ROS, was induced by GA in aleurone cells but suppressed by ABA. Furthermore, exogenous H2O2 appeared to promote the induction of α-amylases by GA. In contrast, antioxidants suppressed the induction of α-amylases. Therefore, H2O2 seems to function in GA and ABA signaling, and in regulation of α-amylase production, in aleurone cells. To identify the target of H2O2 in GA and ABA signaling, we analyzed the interrelationships between H2O2 and DELLA proteins Slender1 (SLN1), GA-regulated Myb transcription factor (GAmyb), and ABA-responsive protein kinase (PKABA) and their roles in GA and ABA signaling in aleurone cells. In the presence of GA, exogenous H2O2 had little effect on the degradation of SLN1, the primary transcriptional repressor mediating GA signaling, but it promoted the production of the mRNA encoding GAMyb, which acts downstream of SLN1 and involves induction of α-amylase mRNA. Additionally, H2O2 suppressed the production of PKABA mRNA, which is induced by ABA:PKABA represses the production of GAMyb mRNA. From these observations, we concluded that H2O2 released the repression of GAMyb mRNA by PKABA and consequently promoted the production of α-amylase mRNA, thus suggesting that the H2O2 generated by GA in aleurone cells is a signal molecule that antagonizes ABA signaling. PMID:22291200

  14. Retinoic acid signaling regulates sonic hedgehog and bone morphogenetic protein signalings during genital tubercle development.

    PubMed

    Liu, Liqing; Suzuki, Kentaro; Nakagata, Naomi; Mihara, Kenichiro; Matsumaru, Daisuke; Ogino, Yukiko; Yashiro, Kenta; Hamada, Hiroshi; Liu, Zhonghua; Evans, Sylvia M; Mendelsohn, Cathy; Yamada, Gen

    2012-02-01

    Retinoic acid (RA) plays pivotal roles in organogenesis, and both excessive and reduced amounts of RA cause developmental abnormalities. Reproductive organs are susceptible to teratogen toxigenicity, and the genital tubercle (GT) is one such representative organ. The physiological function of endogenous RA signaling and the mechanisms of RA-induced teratogenicity are poorly understood during the GT development. The objective of this study is to understand the developmental and teratogenic roles of RA during GT development by analyzing genetically modified mouse models. We found dynamic patterns of gene expression for the RA-synthesizing enzyme, Raldh2, and for the RA-catabolizing enzyme, Cyp26b1, during GT development. Rarb, an indicator gene for RA signaling, starts its expression in the prospective corpus cavernosum penis and in the urethral plate epithelium (UE), which plays central roles during GT development. Excessive RA signaling in Cyp26b1(-/-) mutants leads to abnormal extents of cell proliferation and differentiation during GT development, and also upregulates expression of growth factor signalings. They include Sonic hedgehog (Shh) signaling and Bone morphogenetic protein (Bmp) signaling, which are expressed in the UE and its bilateral mesenchyme. RA signaling positively regulatesShh and Bmp4 expression during GT development as testified also by the experiment of RA administration and analyses of loss-of-function of RA signaling mutants. Thus, RA signaling is involved in the developmental cascade necessary for UE formation and GT development. PMID:22127979

  15. L-Cysteine Desulfhydrase 1 modulates the generation of the signaling molecule sulfide in plant cytosol

    PubMed Central

    Romero, Luis C.; García, Irene; Gotor, Cecilia

    2013-01-01

    Consistent with data in animal systems, experimental evidence highlights sulfide as a signaling molecule of equal importance to NO and H2O2 in plant systems. In mammals, two cytosolic enzymes, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE), have been shown to be responsible for the endogenous production of sulfide. L-cysteine desulfhydrase 1 (DES1) has been recently established as the only enzyme that is involved in the generation of hydrogen sulfide in plant cytosol. Although plants have an available source of sulfide within chloroplasts, the basic stromal pH prevents sulfide release into the cytosol. Therefore, DES1 is essential for the production of sulfide for signaling purposes. PMID:23428891

  16. Structure of the Repulsive Guidance Molecule (RGM)—Neogenin Signaling Hub

    PubMed Central

    Bell, Christian H.; Bishop, Benjamin; Tang, Chenxiang; Gilbert, Robert J.C.; Aricescu, A. Radu; Pasterkamp, R. Jeroen; Siebold, Christian

    2016-01-01

    Repulsive guidance molecule family members (RGMs) control fundamental and diverse cellular processes, including motility and adhesion, immune cell regulation, and systemic iron metabolism. However, it is not known how RGMs initiate signaling through their common cell-surface receptor, neogenin (NEO1). Here, we present crystal structures of the NEO1 RGM-binding region and its complex with human RGMB (also called dragon). The RGMB structure reveals a previously unknown protein fold and a functionally important autocatalytic cleavage mechanism and provides a framework to explain numerous disease-linked mutations in RGMs. In the complex, two RGMB ectodomains conformationally stabilize the juxtamembrane regions of two NEO1 receptors in a pH-dependent manner. We demonstrate that all RGM-NEO1 complexes share this architecture, which therefore represents the core of multiple signaling pathways. PMID:23744777

  17. Differential Targeting of Gβγ-Subunit Signaling with Small Molecules

    NASA Astrophysics Data System (ADS)

    Bonacci, Tabetha M.; Mathews, Jennifer L.; Yuan, Chujun; Lehmann, David M.; Malik, Sundeep; Wu, Dianqing; Font, Jose L.; Bidlack, Jean M.; Smrcka, Alan V.

    2006-04-01

    G protein βγ subunits have potential as a target for therapeutic treatment of a number of diseases. We performed virtual docking of a small-molecule library to a site on Gβγ subunits that mediates protein interactions. We hypothesized that differential targeting of this surface could allow for selective modulation of Gβγ subunit functions. Several compounds bound to Gβγ subunits with affinities from 0.1 to 60 μM and selectively modulated functional Gβγ-protein-protein interactions in vitro, chemotactic peptide signaling pathways in HL-60 leukocytes, and opioid receptor-dependent analgesia in vivo. These data demonstrate an approach for modulation of G protein-coupled receptor signaling that may represent an important therapeutic strategy.

  18. Nonenzymatic catalytic signal amplification for nucleic acid hybridization assays

    NASA Technical Reports Server (NTRS)

    Fan, Wenhong (Inventor); Cassell, Alan M. (Inventor); Han, Jie (Inventor)

    2006-01-01

    Devices, methods, and kits for amplifying the signal from hybridization reactions between nucleic acid probes and their cognate targets are presented. The devices provide partially-duplexed, immobilized probe complexes, spatially separate from and separately addressable from immobilized docking strands. Cognate target acts catalytically to transfer probe from the site of probe complex immobilization to the site of immobilized docking strand, generating a detectable signal. The methods and kits of the present invention may be used to identify the presence of cognate target in a fluid sample.

  19. Retinoic Acid Signaling Affects Cortical Synchrony During Sleep

    NASA Astrophysics Data System (ADS)

    Maret, Stéphanie; Franken, Paul; Dauvilliers, Yves; Ghyselinck, Norbert B.; Chambon, Pierre; Tafti, Mehdi

    2005-10-01

    Delta oscillations, characteristic of the electroencephalogram (EEG) of slow wave sleep, estimate sleep depth and need and are thought to be closely linked to the recovery function of sleep. The cellular mechanisms underlying the generation of delta waves at the cortical and thalamic levels are well documented, but the molecular regulatory mechanisms remain elusive. Here we demonstrate in the mouse that the gene encoding the retinoic acid receptor beta determines the contribution of delta oscillations to the sleep EEG. Thus, retinoic acid signaling, which is involved in the patterning of the brain and dopaminergic pathways, regulates cortical synchrony in the adult.

  20. Vascular Cell Adhesion Molecule-1 Expression and Signaling During Disease: Regulation by Reactive Oxygen Species and Antioxidants

    PubMed Central

    Marchese, Michelle E.; Abdala-Valencia, Hiam

    2011-01-01

    Abstract The endothelium is immunoregulatory in that inhibiting the function of vascular adhesion molecules blocks leukocyte recruitment and thus tissue inflammation. The function of endothelial cells during leukocyte recruitment is regulated by reactive oxygen species (ROS) and antioxidants. In inflammatory sites and lymph nodes, the endothelium is stimulated to express adhesion molecules that mediate leukocyte binding. Upon leukocyte binding, these adhesion molecules activate endothelial cell signal transduction that then alters endothelial cell shape for the opening of passageways through which leukocytes can migrate. If the stimulation of this opening is blocked, inflammation is blocked. In this review, we focus on the endothelial cell adhesion molecule, vascular cell adhesion molecule-1 (VCAM-1). Expression of VCAM-1 is induced on endothelial cells during inflammatory diseases by several mediators, including ROS. Then, VCAM-1 on the endothelium functions as both a scaffold for leukocyte migration and a trigger of endothelial signaling through NADPH oxidase-generated ROS. These ROS induce signals for the opening of intercellular passageways through which leukocytes migrate. In several inflammatory diseases, inflammation is blocked by inhibition of leukocyte binding to VCAM-1 or by inhibition of VCAM-1 signal transduction. VCAM-1 signal transduction and VCAM-1-dependent inflammation are blocked by antioxidants. Thus, VCAM-1 signaling is a target for intervention by pharmacological agents and by antioxidants during inflammatory diseases. This review discusses ROS and antioxidant functions during activation of VCAM-1 expression and VCAM-1 signaling in inflammatory diseases. Antioxid. Redox Signal. 15, 1607–1638. PMID:21050132

  1. Electrochemical detection of nucleic acids, proteins, small molecules and cells using a DNA-nanostructure-based universal biosensing platform.

    PubMed

    Lin, Meihua; Song, Ping; Zhou, Guobao; Zuo, Xiaolei; Aldalbahi, Ali; Lou, Xiaoding; Shi, Jiye; Fan, Chunhai

    2016-07-01

    The occurrence and prognosis of many complex diseases, such as cancers, is associated with the variation of various molecules, including DNA at the genetic level, RNA at the regulatory level, proteins at the functional level and small molecules at the metabolic level (defined collectively as multilevel molecules). Thus it is highly desirable to develop a single platform for detecting multilevel biomarkers for early-stage diagnosis. Here we report a protocol on DNA-nanostructure-based programmable engineering of the biomolecular recognition interface, which provides a universal electrochemical biosensing platform for the ultrasensitive detection of nucleic acids (DNA/RNA), proteins, small molecules and whole cells. The protocol starts with the synthesis of a series of differentially sized, self-assembled tetrahedral DNA nanostructures (TDNs) with site-specifically modified thiol groups that can be readily anchored on the surface of a gold electrode with high reproducibility. By exploiting the rigid structure, nanoscale addressability and versatile functionality of TDNs, one can tailor the type of biomolecular probes appended on individual TDNs for the detection of specific molecules of interest. Target binding occurring on the gold surface patterned with TDNs is quantitatively translated into electrochemical signals via a coupled enzyme-based catalytic process. This uses a sandwich assay strategy in which biotinylated reporter probes recognize TDN-bound target biomolecules, which then allow binding of horseradish-peroxidase-conjugated avidin (avidin-HRP). Hydrogen peroxide (H2O2) is then reduced by avidin-HRP in the presence of TMB (3,3',5,5'-tetramethylbenzidine) to generate a quantitative electrochemical signal. The time range for the entire protocol is ∼1 d, whereas the detection process takes ∼30 min to 3 h. PMID:27310264

  2. Roles of lipids as signaling molecules and mitigators during stress response in plants.

    PubMed

    Okazaki, Yozo; Saito, Kazuki

    2014-08-01

    Lipids are the major constituents of biological membranes that can sense extracellular conditions. Lipid-mediated signaling occurs in response to various environmental stresses, such as temperature change, salinity, drought and pathogen attack. Lysophospholipid, fatty acid, phosphatidic acid, diacylglycerol, inositol phosphate, oxylipins, sphingolipid, and N-acylethanolamine have all been proposed to function as signaling lipids. Studies on these stress-inducible lipid species have demonstrated that each lipid class has specific biological relevance, biosynthetic mechanisms and signaling cascades, which activate defense reactions at the transcriptional level. In addition to their roles in signaling, lipids also function as stress mitigators to reduce the intensity of stressors. To mitigate particular stresses, enhanced syntheses of unique lipids that accumulate in trace quantities under normal growth conditions are often observed under stressed conditions. The accumulation of oligogalactolipids and glucuronosyldiacylglycerol has recently been found to mitigate freezing and nutrition-depletion stresses, respectively, during lipid remodeling. In addition, wax, cutin and suberin, which are not constituents of the lipid bilayer, but are components derived from lipids, contribute to the reduction of drought stress and tissue injury. These features indicate that lipid-mediated defenses against environmental stress contributes to plant survival. PMID:24844563

  3. Comparative analyses of lysophosphatidic acid receptor-mediated signaling.

    PubMed

    Fukushima, Nobuyuki; Ishii, Shoichi; Tsujiuchi, Toshifumi; Kagawa, Nao; Katoh, Kazutaka

    2015-06-01

    Lysophosphatidic acid (LPA) is a bioactive lipid mediator that activates G protein-coupled LPA receptors to exert fundamental cellular functions. Six LPA receptor genes have been identified in vertebrates and are classified into two subfamilies, the endothelial differentiation genes (edg) and the non-edg family. Studies using genetically engineered mice, frogs, and zebrafish have demonstrated that LPA receptor-mediated signaling has biological, developmental, and pathophysiological functions. Computational analyses have also identified several amino acids (aa) critical for LPA recognition by human LPA receptors. This review focuses on the evolutionary aspects of LPA receptor-mediated signaling by comparing the aa sequences of vertebrate LPA receptors and LPA-producing enzymes; it also summarizes the LPA receptor-dependent effects commonly observed in mouse, frog, and fish. PMID:25732591

  4. Control of biofilm-associated infections by signaling molecules and nanoparticles.

    PubMed

    Holban, Alina Maria; Gestal, Monica Cartelle; Grumezescu, Alexandru Mihai

    2016-08-30

    As the severe infections caused by resistant pathogens and biofilm embedded bacteria continue to emerge, alternative antimicrobial strategies could represent a solution. Recent studies support the development of molecular approaches (through signaling molecules) aiming to fight infections by modulating the virulence, behavior and formation of resistance structures such as biofilms. The utilization of such formulations would offer the advantage of reducing the selection of resistant isolates, since most of the proposed molecules do not interfere with the population fitness if utilized in low amounts. Despite the promising results, these therapies are delaying to be applied in the clinical context mainly because of the following: (i) limited knowledge regarding their long and medium term effect, (ii) specific properties that make most of these molecules difficult to be utilized in pharmacological formulations, (iii) low stability, (iv) difficulty to reach a target within the host body, and (v) limited availability. For reducing most of these disadvantages, nanotechnology seem to offer the best option through the development of nanostructured materials and nanoparticles able to improve the efficiency of molecular virulence modulators and novel antimicrobial compounds and to ensure their targeted delivery and controlled release. PMID:26945736

  5. Design and experimental approach to the construction of a human signal-molecule-profiling database.

    PubMed

    Zhao, Xinyan; Dong, Tao

    2013-12-01

    The human signal-molecule-profiling database (HSMPD) is designed as a prospective medical database for translational bioinformatics (TBI). To explore the feasibility of low-cost database construction, we studied the roadmap of HSMPD. A HSMPD-oriented tool, called "signal-molecule-profiling (SMP) chip" was developed for data acquisition, which can be employed in the routine blood tests in hospitals; the results will be stored in the HSMPD system automatically. HSMPD system can provide data services for the TBI community, which generates a stable income to support the data acquisition. The small-scale experimental test was performed in the hospital to verify SMP chips and the demo HSMPD software. One hundred and eighty nine complete SMP records were collected, and the demo HSMPD system was also evaluated in the survey study on patients and doctors. The function of SMP chip was verified, whereas the demo HSMPD software needed to be improved. The survey study showed that patients would only accept free tests of SMP chips when they originally needed blood examinations. The study indicated that the construction of HSMPD relies on the self-motivated cooperation of the TBI community and the traditional healthcare system. The proposed roadmap potentially provides an executable solution to build the HSMPD without high costs. PMID:24351788

  6. Design and Experimental Approach to the Construction of a Human Signal-Molecule-Profiling Database

    PubMed Central

    Zhao, Xinyan; Dong, Tao

    2013-01-01

    The human signal-molecule-profiling database (HSMPD) is designed as a prospective medical database for translational bioinformatics (TBI). To explore the feasibility of low-cost database construction, we studied the roadmap of HSMPD. A HSMPD-oriented tool, called “signal-molecule-profiling (SMP) chip” was developed for data acquisition, which can be employed in the routine blood tests in hospitals; the results will be stored in the HSMPD system automatically. HSMPD system can provide data services for the TBI community, which generates a stable income to support the data acquisition. The small-scale experimental test was performed in the hospital to verify SMP chips and the demo HSMPD software. One hundred and eighty nine complete SMP records were collected, and the demo HSMPD system was also evaluated in the survey study on patients and doctors. The function of SMP chip was verified, whereas the demo HSMPD software needed to be improved. The survey study showed that patients would only accept free tests of SMP chips when they originally needed blood examinations. The study indicated that the construction of HSMPD relies on the self-motivated cooperation of the TBI community and the traditional healthcare system. The proposed roadmap potentially provides an executable solution to build the HSMPD without high costs. PMID:24351788

  7. Programmed Lab Experiments for Biochemical Investigation of Quorum-Sensing Signal Molecules in Rhizospheric Soil Bacteria.

    PubMed

    Nievas, Fiorela L; Bogino, Pablo C; Giordano, Walter

    2016-05-01

    Biochemistry courses in the Department of Molecular Biology at the National University of Río Cuarto, Argentina, are designed for undergraduate students in biology, microbiology, chemistry, agronomy, and veterinary medicine. Microbiology students typically have previous coursework in general, analytical, and organic chemistry. Programmed sequences of lab experiments allow these students to investigate biochemical problems whose solution is feasible within the context of their knowledge and experience. We previously designed and reported a programmed lab experiment that familiarizes microbiology students with techniques for detection and characterization of quorum-sensing (QS) and quorum-quenching (QQ) signal molecules. Here, we describe a sequence of experiments designed to expand the understanding and capabilities of biochemistry students using techniques for extraction and identification of QS and QQ signal molecules from peanut rhizospheric soil bacteria, including culturing and manipulation of bacteria under sterile conditions. The program provides students with an opportunity to perform useful assays, draw conclusions from their results, and discuss possible extensions of the study. © 2016 by The International Union of Biochemistry and Molecular Biology, 44:256-262, 2016. PMID:27027267

  8. Small Molecule Inhibition of Ligand-Stimulated RAGE-DIAPH1 Signal Transduction

    PubMed Central

    Manigrasso, Michaele B.; Pan, Jinhong; Rai, Vivek; Zhang, Jinghua; Reverdatto, Sergey; Quadri, Nosirudeen; DeVita, Robert J.; Ramasamy, Ravichandran; Shekhtman, Alexander; Schmidt, Ann Marie

    2016-01-01

    The receptor for advanced glycation endproducts (RAGE) binds diverse ligands linked to chronic inflammation and disease. NMR spectroscopy and x-ray crystallization studies of the extracellular domains of RAGE indicate that RAGE ligands bind by distinct charge- and hydrophobicity-dependent mechanisms. The cytoplasmic tail (ct) of RAGE is essential for RAGE ligand-mediated signal transduction and consequent modulation of gene expression and cellular properties. RAGE signaling requires interaction of ctRAGE with the intracellular effector, mammalian diaphanous 1 or DIAPH1. We screened a library of 58,000 small molecules and identified 13 small molecule competitive inhibitors of ctRAGE interaction with DIAPH1. These compounds, which exhibit in vitro and in vivo inhibition of RAGE-dependent molecular processes, present attractive molecular scaffolds for the development of therapeutics against RAGE-mediated diseases, such as those linked to diabetic complications, Alzheimer’s disease, and chronic inflammation, and provide support for the feasibility of inhibition of protein-protein interaction (PPI). PMID:26936329

  9. Cross Talk between H2O2 and Interacting Signal Molecules under Plant Stress Response.

    PubMed

    Saxena, Ina; Srikanth, Sandhya; Chen, Zhong

    2016-01-01

    It is well established that oxidative stress is an important cause of cellular damage. During stress conditions, plants have evolved regulatory mechanisms to adapt to various environmental stresses. One of the consequences of stress is an increase in the cellular concentration of reactive oxygen species, which is subsequently converted to H2O2. H2O2 is continuously produced as the byproduct of oxidative plant aerobic metabolism. Organelles with a high oxidizing metabolic activity or with an intense rate of electron flow, such as chloroplasts, mitochondria, or peroxisomes are major sources of H2O2 production. H2O2 acts as a versatile molecule because of its dual role in cells. Under normal conditions, H2O2 immerges as an important factor during many biological processes. It has been established that it acts as a secondary messenger in signal transduction networks. In this review, we discuss potential roles of H2O2 and other signaling molecules during various stress responses. PMID:27200043

  10. Cross Talk between H2O2 and Interacting Signal Molecules under Plant Stress Response

    PubMed Central

    Saxena, Ina; Srikanth, Sandhya; Chen, Zhong

    2016-01-01

    It is well established that oxidative stress is an important cause of cellular damage. During stress conditions, plants have evolved regulatory mechanisms to adapt to various environmental stresses. One of the consequences of stress is an increase in the cellular concentration of reactive oxygen species, which is subsequently converted to H2O2. H2O2 is continuously produced as the byproduct of oxidative plant aerobic metabolism. Organelles with a high oxidizing metabolic activity or with an intense rate of electron flow, such as chloroplasts, mitochondria, or peroxisomes are major sources of H2O2 production. H2O2 acts as a versatile molecule because of its dual role in cells. Under normal conditions, H2O2 immerges as an important factor during many biological processes. It has been established that it acts as a secondary messenger in signal transduction networks. In this review, we discuss potential roles of H2O2 and other signaling molecules during various stress responses. PMID:27200043

  11. Variant fatty acid-like molecules Conjugation, novel approaches for extending the stability of therapeutic peptides

    PubMed Central

    Li, Ying; Wang, Yuli; Wei, Qunchao; Zheng, Xuemin; Tang, Lida; Kong, Dexin; Gong, Min

    2015-01-01

    The multiple physiological properties of glucagon-like peptide-1 (GLP-1) make it a promising drug candidate for the treatment of type 2 diabetes. However, the in vivo half-life of GLP-1 is short due to rapid degradation by dipeptidyl peptidase-IV (DPP-IV) and renal clearance. The poor stability of GLP-1 has significantly limited its clinical utility; however, many studies are focused on extending its stability. Fatty acid conjugation is a traditional approach for extending the stability of therapeutic peptides because of the high binding affinity of human serum albumin for fatty acids. However, the conjugate requires a complex synthetic approach, usually involving Lys and occasionally involving a linker. In the current study, we conjugated the GLP-1 molecule with fatty acid derivatives to simplify the synthesis steps. Human serum albumin binding assays indicated that the retained carboxyl groups of the fatty acids helped maintain a tight affinity to HSA. The conjugation of fatty acid-like molecules improved the stability and increased the binding affinity of GLP-1 to HSA. The use of fatty acid-like molecules as conjugating components allowed variant conjugation positions and freed carboxyl groups for other potential uses. This may be a novel, long-acting strategy for the development of therapeutic peptides. PMID:26658631

  12. Variant fatty acid-like molecules Conjugation, novel approaches for extending the stability of therapeutic peptides.

    PubMed

    Li, Ying; Wang, Yuli; Wei, Qunchao; Zheng, Xuemin; Tang, Lida; Kong, Dexin; Gong, Min

    2015-01-01

    The multiple physiological properties of glucagon-like peptide-1 (GLP-1) make it a promising drug candidate for the treatment of type 2 diabetes. However, the in vivo half-life of GLP-1 is short due to rapid degradation by dipeptidyl peptidase-IV (DPP-IV) and renal clearance. The poor stability of GLP-1 has significantly limited its clinical utility; however, many studies are focused on extending its stability. Fatty acid conjugation is a traditional approach for extending the stability of therapeutic peptides because of the high binding affinity of human serum albumin for fatty acids. However, the conjugate requires a complex synthetic approach, usually involving Lys and occasionally involving a linker. In the current study, we conjugated the GLP-1 molecule with fatty acid derivatives to simplify the synthesis steps. Human serum albumin binding assays indicated that the retained carboxyl groups of the fatty acids helped maintain a tight affinity to HSA. The conjugation of fatty acid-like molecules improved the stability and increased the binding affinity of GLP-1 to HSA. The use of fatty acid-like molecules as conjugating components allowed variant conjugation positions and freed carboxyl groups for other potential uses. This may be a novel, long-acting strategy for the development of therapeutic peptides. PMID:26658631

  13. Dissecting Abscisic Acid Signaling Pathways Involved in Cuticle Formation.

    PubMed

    Cui, Fuqiang; Brosché, Mikael; Lehtonen, Mikko T; Amiryousefi, Ali; Xu, Enjun; Punkkinen, Matleena; Valkonen, Jari P T; Fujii, Hiroaki; Overmyer, Kirk

    2016-06-01

    The cuticle is the outer physical barrier of aerial plant surfaces and an important interaction point between plants and the environment. Many environmental stresses affect cuticle formation, yet the regulatory pathways involved remain undefined. We used a genetics and gene expression analysis in Arabidopsis thaliana to define an abscisic acid (ABA) signaling loop that positively regulates cuticle formation via the core ABA signaling pathway, including the PYR/PYL receptors, PP2C phosphatase, and SNF1-Related Protein Kinase (SnRK) 2.2/SnRK2.3/SnRK2.6. Downstream of the SnRK2 kinases, cuticle formation was not regulated by the ABA-responsive element-binding transcription factors but rather by DEWAX, MYB16, MYB94, and MYB96. Additionally, low air humidity increased cuticle formation independent of the core ABA pathway and cell death/reactive oxygen species signaling attenuated expression of cuticle-biosynthesis genes. In Physcomitrella patens, exogenous ABA suppressed expression of cuticle-related genes, whose Arabidopsis orthologs were ABA-induced. Hence, the mechanisms regulating cuticle formation are conserved but sophisticated in land plants. Signaling specifically related to cuticle deficiency was identified to play a major role in the adaptation of ABA signaling pathway mutants to increased humidity and in modulating their immunity to Botrytis cinerea in Arabidopsis. These results define a cuticle-specific downstream branch in the ABA signaling pathway that regulates responses to the external environment. PMID:27060495

  14. Disulfuric acid dissociated by two water molecules: ab initio and density functional theory calculations.

    PubMed

    Kim, Seong Kyu; Lee, Han Myoung; Kim, Kwang S

    2015-11-21

    We have studied geometries, energies and vibrational spectra of disulfuric acid (H2S2O7) and its anion (HS2O7(-)) hydrated by a few water molecules, using density functional theory (M062X) and ab initio theory (SCS-MP2 and CCSD(T)). The most noteworthy result is found in H2S2O7(H2O)2 in which the lowest energy conformer shows deprotonated H2S2O7. Thus, H2S2O7 requires only two water molecules, the fewest number of water molecules for deprotonation among various hydrated monomeric acids reported so far. Even the second deprotonation of the first deprotonated species HS2O7(-) needs only four water molecules. The deprotonation is supported by vibration spectra, in which acid O-H stretching peaks disappear and specific three O-H stretching peaks for H3O(+) (eigen structure) appear. We have also kept track of variations in several geometrical parameters, atomic charges, and hybrid orbital characters upon addition of water. As the number of water molecules added increases, the S-O bond weakens in the case of H2S2O7, but strengthens in the case of HS2O7(-). It implies that the decomposition leading to H2SO4 and SO3 hardly occurs prior to the 2nd deprotonation at low temperatures. PMID:26400266

  15. Identification and Characterization of a Novel Small-Molecule Inhibitor of β-Catenin Signaling

    PubMed Central

    Delgado, Evan R.; Yang, Jing; So, Juhoon; Leimgruber, Stephanie; Kahn, Michael; Ishitani, Tohru; Shin, Donghun; Mustata Wilson, Gabriela; Monga, Satdarshan P.

    2015-01-01

    Hepatocellular carcinoma (HCC), the third most common cause of cancer-related deaths worldwide, lacks effective medical therapy. Large subsets of HCC demonstrate Wnt/β-catenin activation, making this an attractive therapeutic target. We report strategy and characterization of a novel small-molecule inhibitor, ICG-001, known to affect Wnt signaling by disrupting β-catenin–CREB binding protein interactions. We queried the ZINC online database for structural similarity to ICG-001 and identified PMED-1 as the lead compound, with ≥70% similarity to ICG-001. PMED-1 significantly reduced β-catenin activity in hepatoblastoma and several HCC cells, as determined by TOPflash reporter assay, with an IC50 ranging from 4.87 to 32 μmol/L. Although no toxicity was observed in primary human hepatocytes, PMED-1 inhibited Wnt target expression in HCC cells, including those with CTNNB1 mutations, and impaired cell proliferation and viability. PMED-1 treatment decreased β-catenin–CREB binding protein interactions without affecting total β-catenin levels or activity of other common kinases. PMED-1 treatment of Tg(OTM:d2EGFP) zebrafish expressing GFP under the β-catenin/Tcf reporter led to a notable decrease in β-catenin activity. The PMED effect on β-catenin signaling lasted from 12 to 24 hours in vitro and 6 to 15 hours in vivo. Thus, using a rapid and cost-effective computational methodology, we have identified a novel and specific small-molecule inhibitor of Wnt signaling that may have implications for HCC treatment. PMID:24819961

  16. Endothelial juxtaposition of distinct adult stem cells activates angiogenesis signaling molecules in endothelial cells.

    PubMed

    Mohammadi, Elham; Nassiri, Seyed Mahdi; Rahbarghazi, Reza; Siavashi, Vahid; Araghi, Atefeh

    2015-12-01

    Efficacy of therapeutic angiogenesis needs a comprehensive understanding of endothelial cell (EC) function and biological factors and cells that interplay with ECs. Stem cells are considered the key components of pro- and anti-angiogenic milieu in a wide variety of physiopathological states, and interactions of EC-stem cells have been the subject of controversy in recent years. In this study, the potential effects of three tissue-specific adult stem cells, namely rat marrow-derived mesenchymal stem cells (rBMSCs), rat adipose-derived stem cells (rADSCs) and rat muscle-derived satellite cells (rSCs), on the endothelial activation of key angiogenic signaling molecules, including VEGF, Ang-2, VEGFR-2, Tie-2, and Tie2-pho, were investigated. Human umbilical vein endothelial cells (HUVECs) and rat lung microvascular endothelial cells (RLMECs) were cocultured with the stem cells or incubated with the stem cell-derived conditioned media on Matrigel. Following HUVEC-stem cell coculture, CD31-positive ECs were flow sorted and subjected to western blotting to analyze potential changes in the expression of the pro-angiogenic signaling molecules. Elongation and co-alignment of the stem cells were seen along the EC tubes in the EC-stem cell cocultures on Matrigel, with cell-to-cell dye communication in the EC-rBMSC cocultures. Moreover, rBMSCs and rADSCs significantly improved endothelial tubulogenesis in both juxtacrine and paracrine manners. These two latter stem cells dynamically up-regulated VEGF, Ang-2, VREGR-2, and Tie-2 but down-regulated Tie2-pho and the Tie2-pho/Tie-2 ratio in HUVECs. Induction of pro-angiogenic signaling in ECs by marrow- and adipose-derived MSCs further indicates the significance of stem cell milieu in angiogenesis dynamics. PMID:26068799

  17. A stromal interaction molecule 1 variant up-regulates matrix metalloproteinase-2 expression by strengthening nucleoplasmic Ca2+ signaling.

    PubMed

    Chen, Fengrong; Zhu, Liping; Cai, Lei; Zhang, Jiwei; Zeng, Xianqin; Li, Jiansha; Su, Yuan; Hu, Qinghua

    2016-04-01

    Very recent studies hold promise to reveal the role of stromal interaction molecule 1 (STIM1) in non-store-operated Ca2+ entry. Here we showed that in contrast to cytoplasmic membrane redistribution as previously noted, human umbilical vein endothelial STIM1 with a T-to-C nucleotide transition resulting in an amino acid substitution of leucine by proline in the signal peptide sequence translocated to perinuclear membrane upon intracellular Ca2+ depletion, amplified nucleoplasmic Ca2+ signaling through ryanodine receptor-dependent pathway, and enhanced the subsequent cAMP responsive element binding protein activity, matrix metalloproteinase-2 (MMP-2) gene expression, and endothelial tube forming. The abundance of mutated STIM1 and the MMP-2 expression were higher in native human umbilical vein endothelial cells of patients with gestational hypertension than controls and were significantly correlated with blood pressure. These findings broaden our understanding about structure-function bias of STIM1 and offer unique insights into its application in nucleoplasmic Ca2+, MMP-2 expression, endothelial dysfunction, and pathophysiological mechanism(s) of gestational hypertension. PMID:26775216

  18. Farnesoid X receptor alpha: a molecular link between bile acids and steroid signaling?

    PubMed

    Baptissart, Marine; Vega, Aurelie; Martinot, Emmanuelle; Baron, Silvère; Lobaccaro, Jean-Marc A; Volle, David H

    2013-12-01

    Bile acids are cholesterol metabolites that have been extensively studied in recent decades. In addition to having ancestral roles in digestion and fat solubilization, bile acids have recently been described as signaling molecules involved in many physiological functions, such as glucose and energy metabolisms. These signaling pathways involve the activation of the nuclear receptor farnesoid X receptor (FXRα) or of the G protein-coupled receptor TGR5. In this review, we will focus on the emerging role of FXRα, suggesting important functions for the receptor in steroid metabolism. It has been described that FXRα is expressed in the adrenal glands and testes, where it seems to control steroid production. FXRα also participates in steroid catabolism in the liver and interferes with the steroid signaling pathways in target tissues via crosstalk with steroid receptors. In this review, we discuss the potential impacts of bile acid (BA), through its interactions with steroid metabolism, on glucose metabolism, sexual function, and prostate and breast cancers. Although several of the published reports rely on in vitro studies, they highlight the need to understand the interactions that may affect health. This effect is important because BA levels are increased in several pathophysiological conditions related to liver injuries. Additionally, BA receptors are targeted clinically using therapeutics to treat liver diseases, diabetes, and cancers. PMID:23784309

  19. Calcium specificity signaling mechanisms in abscisic acid signal transduction in Arabidopsis guard cells.

    PubMed

    Brandt, Benjamin; Munemasa, Shintaro; Wang, Cun; Nguyen, Desiree; Yong, Taiming; Yang, Paul G; Poretsky, Elly; Belknap, Thomas F; Waadt, Rainer; Alemán, Fernando; Schroeder, Julian I

    2015-01-01

    A central question is how specificity in cellular responses to the eukaryotic second messenger Ca(2+) is achieved. Plant guard cells, that form stomatal pores for gas exchange, provide a powerful system for in depth investigation of Ca(2+)-signaling specificity in plants. In intact guard cells, abscisic acid (ABA) enhances (primes) the Ca(2+)-sensitivity of downstream signaling events that result in activation of S-type anion channels during stomatal closure, providing a specificity mechanism in Ca(2+)-signaling. However, the underlying genetic and biochemical mechanisms remain unknown. Here we show impairment of ABA signal transduction in stomata of calcium-dependent protein kinase quadruple mutant plants. Interestingly, protein phosphatase 2Cs prevent non-specific Ca(2+)-signaling. Moreover, we demonstrate an unexpected interdependence of the Ca(2+)-dependent and Ca(2+)-independent ABA-signaling branches and the in planta requirement of simultaneous phosphorylation at two key phosphorylation sites in SLAC1. We identify novel mechanisms ensuring specificity and robustness within stomatal Ca(2+)-signaling on a cellular, genetic, and biochemical level. PMID:26192964

  20. Calcium specificity signaling mechanisms in abscisic acid signal transduction in Arabidopsis guard cells

    PubMed Central

    Brandt, Benjamin; Munemasa, Shintaro; Wang, Cun; Nguyen, Desiree; Yong, Taiming; Yang, Paul G; Poretsky, Elly; Belknap, Thomas F; Waadt, Rainer; Alemán, Fernando; Schroeder, Julian I

    2015-01-01

    A central question is how specificity in cellular responses to the eukaryotic second messenger Ca2+ is achieved. Plant guard cells, that form stomatal pores for gas exchange, provide a powerful system for in depth investigation of Ca2+-signaling specificity in plants. In intact guard cells, abscisic acid (ABA) enhances (primes) the Ca2+-sensitivity of downstream signaling events that result in activation of S-type anion channels during stomatal closure, providing a specificity mechanism in Ca2+-signaling. However, the underlying genetic and biochemical mechanisms remain unknown. Here we show impairment of ABA signal transduction in stomata of calcium-dependent protein kinase quadruple mutant plants. Interestingly, protein phosphatase 2Cs prevent non-specific Ca2+-signaling. Moreover, we demonstrate an unexpected interdependence of the Ca2+-dependent and Ca2+-independent ABA-signaling branches and the in planta requirement of simultaneous phosphorylation at two key phosphorylation sites in SLAC1. We identify novel mechanisms ensuring specificity and robustness within stomatal Ca2+-signaling on a cellular, genetic, and biochemical level. DOI: http://dx.doi.org/10.7554/eLife.03599.001 PMID:26192964

  1. Identification of uric acid as the redox molecule secreted by the yeast Arxula adeninivorans.

    PubMed

    Williams, Jonathan; Trautwein-Schult, Anke; Jankowska, Dagmara; Kunze, Gotthard; Squire, Marie A; Baronian, Keith

    2014-03-01

    The yeast Arxula adeninivorans has been previously shown to secrete a large amount of an electro-active molecule. The molecule was produced by cells that had been cultivated in a rich medium, harvested, washed and then suspended in phosphate-buffered saline (PBS). The molecule was easily detectable after 60 min of incubation in PBS, and the cells continued to produce the molecule in these conditions for up to 3 days. The peak anodic potential of the oxidation peak was 0.42 V, and it was shown to be a solution species rather than a cell-attached species. We have optimised the production of the molecule, identified it by high-pressure liquid chromatography (HPLC) fractionation and high-resolution mass spectrometric analysis and determined the pathway involved in its synthesis. It has a mass/charge ratio that corresponds to uric acid, and this identification was supported by comparing UV spectra and cyclic voltammograms of the samples to those of uric acid. An A. adeninivorans xanthine oxidase gene disruption mutant failed to produce uric acid, which added further validity to this identification. It also demonstrated that the purine catabolism pathway is involved in its production. A transgenic A. adeninivorans strain with a switchable urate oxidase gene (AUOX) accumulated uric acid when the gene was switched off but did not when the gene was switched on. Cultivation of cells on amino acid and purine-free minimal media with an inorganic nitrogen source suggests that the cells synthesise purines from inorganic nitrogen and proceed to degrade them via the normal purine degradation pathway. PMID:24407453

  2. CO(2) acts as a signalling molecule in populations of the fungal pathogen Candida albicans.

    PubMed

    Hall, Rebecca A; De Sordi, Luisa; Maccallum, Donna M; Topal, Hüsnü; Eaton, Rebecca; Bloor, James W; Robinson, Gary K; Levin, Lonny R; Buck, Jochen; Wang, Yue; Gow, Neil A R; Steegborn, Clemens; Mühlschlegel, Fritz A

    2010-01-01

    When colonising host-niches or non-animated medical devices, individual cells of the fungal pathogen Candida albicans expand into significant biomasses. Here we show that within such biomasses, fungal metabolically generated CO(2) acts as a communication molecule promoting the switch from yeast to filamentous growth essential for C. albicans pathology. We find that CO(2)-mediated intra-colony signalling involves the adenylyl cyclase protein (Cyr1p), a multi-sensor recently found to coordinate fungal responses to serum and bacterial peptidoglycan. We further identify Lys 1373 as essential for CO(2)/bicarbonate regulation of Cyr1p. Disruption of the CO(2)/bicarbonate receptor-site interferes selectively with C. albicans filamentation within fungal biomasses. Comparisons between the Drosophila melanogaster infection model and the mouse model of disseminated candidiasis, suggest that metabolic CO(2) sensing may be important for initial colonisation and epithelial invasion. Our results reveal the existence of a gaseous Candida signalling pathway and its molecular mechanism and provide insights into an evolutionary conserved CO(2)-signalling system. PMID:21124988

  3. Is L-lactate a novel signaling molecule in the brain?

    PubMed Central

    Mosienko, Valentina; Teschemacher, Anja G; Kasparov, Sergey

    2015-01-01

    In the brain, L-lactate is produced by both neurons and astrocytes. There is no doubt that neurons use L-lactate as a supplementary fuel although the importance of this energy source is disputed. Irrespective of its caloric value, L-lactate might also have a signaling role in the brain. Here, we review several current hypotheses of L-lactate mediated signaling. Some proposed mechanisms require L-lactate entry into the neurons leading to a shift in ATP/ADP ratio or redox state. Others postulate interaction with either known receptor HCA1 (GPR81) or a novel, yet unidentified receptor. We argue that the sensitivity of any such mechanism has to match the concentration range of extracellular L-lactate, which is less than ~1.5 mmol/L under physiologic conditions. From that point of view, some of the proposed mechanisms require supraphysiologic levels of L-lactate and could be engaged during ischemia or seizures when L-lactate concentration rises dramatically. Currently, we do not know whether L-lactate production in the brain occurs in microdomains, which might create higher than average local concentrations. Nevertheless, it is clear that in the brain, as in the peripheral tissues, L-lactate is not only used as a source of energy but also acts as a signaling molecule. PMID:25920953

  4. Single molecule analysis of B cell receptor motion during signaling activation

    NASA Astrophysics Data System (ADS)

    Rey Suarez, Ivan; Koo, Peter; Mochrie, Simon; Song, Wenxia; Upadhyaya, Arpita

    B cells are an essential part of the adaptive immune system. They patrol the body looking for signs of infection in the form of antigen on the surface of antigen presenting cells. The binding of the B cell receptor (BCR) to antigen induces signaling cascades that lead to B cell activation and eventual production of high affinity antibodies. During activation, BCR organize into signaling microclusters, which are platforms for signal amplification. The physical processes underlying receptor movement and aggregation are not well understood. Here we study the dynamics of single BCRs on activated murine primary B cells using TIRF imaging and single particle tracking. The tracks obtained are analyzed using perturbation expectation-maximization (pEM) a systems-level analysis that allows the identification of different short-time diffusive states from a set of single particle tracks. We identified five different diffusive states on wild type cells, which correspond to different molecular states of the BCR. By using actin polymerization inhibitors and mutant cells lacking important actin regulators we were able to identify the BCR molecule configuration associated with each diffusive state.

  5. Cadmium induces retinoic acid signaling by regulating retinoic acid metabolic gene expression.

    PubMed

    Cui, Yuxia; Freedman, Jonathan H

    2009-09-11

    The transition metal cadmium is an environmental teratogen. In addition, cadmium and retinoic acid can act synergistically to induce forelimb malformations. The molecular mechanism underlying the teratogenicity of cadmium and the synergistic effect with retinoic acid has not been addressed. An evolutionarily conserved gene, beta,beta-carotene 15,15'-monooxygenase (BCMO), which is involved in retinoic acid biosynthesis, was studied in both Caenorhabditis elegans and murine Hepa 1-6 cells. In C. elegans, bcmo-1 was expressed in the intestine and was cadmium inducible. Similarly, in Hepa 1-6 cells, Bcmo1 was induced by cadmium. Retinoic acid-mediated signaling increased after 24-h exposures to 5 and 10 microm cadmium in Hepa 1-6 cells. Examination of gene expression demonstrated that the induction of retinoic acid signaling by cadmium may be mediated by overexpression of Bcmo1. Furthermore, cadmium inhibited the expression of Cyp26a1 and Cyp26b1, which are involved in retinoic acid degradation. These results indicate that cadmium-induced teratogenicity may be due to the ability of the metal to increase the levels of retinoic acid by disrupting the expression of retinoic acid-metabolizing genes. PMID:19556237

  6. Cadmium Induces Retinoic Acid Signaling by Regulating Retinoic Acid Metabolic Gene Expression*

    PubMed Central

    Cui, Yuxia; Freedman, Jonathan H.

    2009-01-01

    The transition metal cadmium is an environmental teratogen. In addition, cadmium and retinoic acid can act synergistically to induce forelimb malformations. The molecular mechanism underlying the teratogenicity of cadmium and the synergistic effect with retinoic acid has not been addressed. An evolutionarily conserved gene, β,β-carotene 15,15′-monooxygenase (BCMO), which is involved in retinoic acid biosynthesis, was studied in both Caenorhabditis elegans and murine Hepa 1–6 cells. In C. elegans, bcmo-1 was expressed in the intestine and was cadmium inducible. Similarly, in Hepa 1–6 cells, Bcmo1 was induced by cadmium. Retinoic acid-mediated signaling increased after 24-h exposures to 5 and 10 μm cadmium in Hepa 1–6 cells. Examination of gene expression demonstrated that the induction of retinoic acid signaling by cadmium may be mediated by overexpression of Bcmo1. Furthermore, cadmium inhibited the expression of Cyp26a1 and Cyp26b1, which are involved in retinoic acid degradation. These results indicate that cadmium-induced teratogenicity may be due to the ability of the metal to increase the levels of retinoic acid by disrupting the expression of retinoic acid-metabolizing genes. PMID:19556237

  7. Single molecule DNA interaction kinetics of retroviral nucleic acid chaperone proteins

    NASA Astrophysics Data System (ADS)

    Williams, Mark

    2010-03-01

    Retroviral nucleocapsid (NC) proteins are essential for several viral replication processes including specific genomic RNA packaging and reverse transcription. The nucleic acid chaperone activity of NC facilitates the latter process. In this study, we use single molecule biophysical methods to quantify the DNA interactions of wild type and mutant human immunodeficiency virus type 1 (HIV-1) NC and Gag and human T-cell leukemia virus type 1 (HTLV-1) NC. We find that the nucleic acid interaction properties of these proteins differ significantly, with HIV-1 NC showing rapid protein binding kinetics, significant duplex destabilization, and strong DNA aggregation, all properties that are critical components of nucleic acid chaperone activity. In contrast, HTLV-1 NC exhibits significant destabilization activity but extremely slow DNA interaction kinetics and poor aggregating capability, which explains why HTLV-1 NC is a poor nucleic acid chaperone. To understand these results, we developed a new single molecule method for quantifying protein dissociation kinetics, and applied this method to probe the DNA interactions of wild type and mutant HIV-1 and HTLV-1 NC. We find that mutations to aromatic and charged residues strongly alter the proteins' nucleic acid interaction kinetics. Finally, in contrast to HIV-1 NC, HIV-1 Gag, the nucleic acid packaging protein that contains NC as a domain, exhibits relatively slow binding kinetics, which may negatively impact its ability to act as a nucleic acid chaperone.

  8. Investigation of Pyridine Carboxylic Acids in CM2 Carbonaceous Chondrites: Potential Precursor Molecules for Ancient Coenzymes

    NASA Technical Reports Server (NTRS)

    Smith, Karen E.; Callahan, Michael P.; Gerakines, Perry A.; Dworkin, Jason P.; House, Christopher H.

    2014-01-01

    The distribution and abundances of pyridine carboxylic acids (including nicotinic acid) in eight CM2 carbonaceous chondrites (ALH 85013, DOM 03183, DOM 08003, EET 96016, LAP 02333, LAP 02336, LEW 85311, and WIS 91600) were investigated by liquid chromatography coupled to UV detection and high resolution Orbitrap mass spectrometry. We find that pyridine monocarboxylic acids are prevalent in CM2-type chondrites and their abundance negatively correlates with the degree of pre-terrestrial aqueous alteration that the meteorite parent body experienced. We lso report the first detection of pyridine dicarboxylic acids in carbonaceous chondrites. Additionally, we carried out laboratory studies of proton-irradiated pyridine in carbon dioxide-rich ices (a 1:1 mixture) to serve as a model of the interstellar ice chemistry that may have led to the synthesis of pyridine carboxylic acids. Analysis of the irradiated ice residue shows that a comparable suite of pyridine mono- and dicarboxylic acids was produced, although aqueous alteration may still play a role in the synthesis (and ultimate yield) of these compounds in carbonaceous meteorites. Nicotinic acid is a precursor to nicotinamide adenine dinucleotide, a likely ancient molecule used in cellular metabolism in all of life, and its common occurrence in CM2 chondrites may indicate that meteorites may have been a source of molecules for the emergence of more complex coenzymes on the early Earth.

  9. Investigation of Pyridine Carboxylic Acids in CM2 Carbonaceous Chondrites: Potential Precursor Molecules for Ancient Coenzymes

    NASA Technical Reports Server (NTRS)

    Smith, Karen E.; Callahan, Michael P.; Gerakines, Perry A.; Dworkin, Jason P.; House, Christopher H.

    2014-01-01

    The distribution and abundances of pyridine carboxylic acids (including nicotinic acid) in eight CM2 carbonaceous chondrites (ALH 85013, DOM 03183, DOM 08003, EET 96016, LAP 02333, LAP 02336, LEW 85311, and WIS 91600) were investigated by liquid chromatography coupled to UV detection and high resolution Orbitrap mass spectrometry. We find that pyridine monocarboxylic acids are prevalent in CM2-type chondrites and their abundance negatively correlates with the degree of pre-terrestrial aqueous alteration that the meteorite parent body experienced. We also report the first detection of pyridine dicarboxylic acids in carbonaceous chondrites. Additionally, we carried out laboratory studies of proton-irradiated pyridine in carbon dioxide-rich ices (a 1:1 mixture) to serve as a model of the interstellar ice chemistry that may have led to the synthesis of pyridine carboxylic acids. Analysis of the irradiated ice residue shows that a comparable suite of pyridine mono- and dicarboxylic acids was produced, although aqueous alteration may still play a role in the synthesis (and ultimate yield) of these compounds in carbonaceous meteorites. Nicotinic acid is a precursor to nicotinamide adenine dinucleotide, a likely ancient molecule used in cellular metabolism in all of life, and its common occurrence in CM2 chondrites may indicate that meteorites may have been a source of molecules for the emergence of more complex coenzymes on the early Earth.

  10. Single-molecule studies of acidity distributions in mesoporous aluminosilicate thin films.

    PubMed

    Sun, Xiaojiao; Xie, Jingyi; Xu, Jiayi; Higgins, Daniel A; Hohn, Keith L

    2015-05-26

    Solid acid catalysts are important for many petrochemical processes. The ensemble methods most often employed to characterize acid site properties in catalyst materials provide limited insights into their heterogeneity. Single-molecule (SM) fluorescence spectroscopic methods provide a valuable route to probing the properties of individual microenvironments. In this work, dual-color SM methods are adopted to study acidity distributions in mesoporous aluminosilicate (Al-Si) films prepared by the sol-gel method. The highly fluorescent pH-sensitive dye C-SNARF-1 was employed as a probe. The ratio of C-SNARF-1 emission in two bands centered at 580 and 640 nm provides an effective means to sense the pH of bulk solutions. In mesoporous thin films, SM emission data provide a measure of the effective pH of the microenvironment in which each molecule resides. SM emission data were obtained from mesoporous Al-Si films as a function of Al2O3 content for films ranging from 0% to 30% alumina. Histograms of the emission ratio reveal a broad distribution of acidity properties, with the film microenvironments becoming more acidic, on average, as the alumina content of the films increases. This work provides new insights into the distribution of Brønsted acidity in solid acids that cannot be obtained by conventional means. PMID:25941900

  11. Investigation of pyridine carboxylic acids in CM2 carbonaceous chondrites: Potential precursor molecules for ancient coenzymes

    NASA Astrophysics Data System (ADS)

    Smith, Karen E.; Callahan, Michael P.; Gerakines, Perry A.; Dworkin, Jason P.; House, Christopher H.

    2014-07-01

    The distribution and abundances of pyridine carboxylic acids (including nicotinic acid) in eight CM2 carbonaceous chondrites (ALH 85013, DOM 03183, DOM 08003, EET 96016, LAP 02333, LAP 02336, LEW 85311, and WIS 91600) were investigated by liquid chromatography coupled to UV detection and high resolution Orbitrap mass spectrometry. We find that pyridine monocarboxylic acids are prevalent in CM2-type chondrites and their abundance negatively correlates with the degree of pre-terrestrial aqueous alteration that the meteorite parent body experienced. We also report the first detection of pyridine dicarboxylic acids in carbonaceous chondrites. Additionally, we carried out laboratory studies of proton-irradiated pyridine in carbon dioxide-rich ices (a 1:1 mixture) to serve as a model of the interstellar ice chemistry that may have led to the synthesis of pyridine carboxylic acids. Analysis of the irradiated ice residue shows that a comparable suite of pyridine mono- and dicarboxylic acids was produced, although aqueous alteration may still play a role in the synthesis (and ultimate yield) of these compounds in carbonaceous meteorites. Nicotinic acid is a precursor to nicotinamide adenine dinucleotide, a likely ancient molecule used in cellular metabolism in all of life, and its common occurrence in CM2 chondrites may indicate that meteorites may have been a source of molecules for the emergence of more complex coenzymes on the early Earth.

  12. From carrot to clinic: an overview of the retinoic acid signaling pathway.

    PubMed

    Theodosiou, Maria; Laudet, Vincent; Schubert, Michael

    2010-05-01

    Vitamin A is essential for the formation and maintenance of many body tissues. It is also important for embryonic growth and development and can act as a teratogen at critical periods of development. Retinoic acid (RA) is the biologically active form of vitamin A and its signaling is mediated by the RA and retinoid X receptors. In addition to its role as an important molecule during development, RA has also been implicated in clinical applications, both as a potential anti-tumor agent as well as for the treatment of skin diseases. This review presents an overview of how dietary retinoids are converted to RA, hence presenting the major players in RA metabolism and signaling, and highlights examples of treatment applications of retinoids. Moreover, we discuss the origin and diversification of the retinoid pathway, which are important factors for understanding the evolution of ligand-specificity among retinoid receptors. PMID:20140749

  13. Conformational dynamics of nucleic acid molecules studied by PELDOR spectroscopy with rigid spin labels

    NASA Astrophysics Data System (ADS)

    Prisner, T. F.; Marko, A.; Sigurdsson, S. Th.

    2015-03-01

    Nucleic acid molecules can adopt a variety of structures and exhibit a large degree of conformational flexibility to fulfill their various functions in cells. Here we describe the use of Pulsed Electron-Electron Double Resonance (PELDOR or DEER) to investigate nucleic acid molecules where two cytosine analogs have been incorporated as spin probes. Because these new types of spin labels are rigid and incorporated into double stranded DNA and RNA molecules, there is no additional flexibility of the spin label itself present. Therefore the magnetic dipole-dipole interaction between both spin labels encodes for the distance as well as for the mutual orientation between the spin labels. All of this information can be extracted by multi-frequency/multi-field PELDOR experiments, which gives very precise and valuable information about the structure and conformational flexibility of the nucleic acid molecules. We describe in detail our procedure to obtain the conformational ensembles and show the accuracy and limitations with test examples and application to double-stranded DNA.

  14. Small-Volume Analysis of Cell–Cell Signaling Molecules in the Brain

    PubMed Central

    Romanova, Elena V; Aerts, Jordan T; Croushore, Callie A; Sweedler, Jonathan V

    2014-01-01

    Modern science is characterized by integration and synergy between research fields. Accordingly, as technological advances allow new and more ambitious quests in scientific inquiry, numerous analytical and engineering techniques have become useful tools in biological research. The focus of this review is on cutting edge technologies that aid direct measurement of bioactive compounds in the nervous system to facilitate fundamental research, diagnostics, and drug discovery. We discuss challenges associated with measurement of cell-to-cell signaling molecules in the nervous system, and advocate for a decrease of sample volumes to the nanoliter volume regimen for improved analysis outcomes. We highlight effective approaches for the collection, separation, and detection of such small-volume samples, present strategies for targeted and discovery-oriented research, and describe the required technology advances that will empower future translational science. PMID:23748227

  15. Chemical ‘Jekyll and Hyde’s: Small-molecule inhibitors of developmental signaling pathways†

    PubMed Central

    Sakata, Tomoyo; Chen, James K.

    2011-01-01

    Small molecules that perturb developmental signaling pathways can have devastating effects on embryonic patterning, as evidenced by the chemically induced onset of cyclopic lambs and children with severely shortened limbs during the 1950s. Recent studies, however, have revealed critical roles for these pathways in human disorders and diseases, spurring the re-examination of these compounds as new targeted therapies. In this tutorial review, we describe four case studies of teratogenic compounds, including inhibitors of the Hedgehog (Hh), Wnt, and bone morphogenetic protein (BMP) pathways. We discuss how these teratogens were discovered, their mechanisms of action, their utility as molecular probes, and their potential as therapeutic agents. We also consider current challenges in the field and possible directions for future research. PMID:21505654

  16. Nitrogen modulation of legume root architecture signaling pathways involves phytohormones and small regulatory molecules

    PubMed Central

    Mohd-Radzman, Nadiatul A.; Djordjevic, Michael A.; Imin, Nijat

    2013-01-01

    Nitrogen, particularly nitrate is an important yield determinant for crops. However, current agricultural practice with excessive fertilizer usage has detrimental effects on the environment. Therefore, legumes have been suggested as a sustainable alternative for replenishing soil nitrogen. Legumes can uniquely form nitrogen-fixing nodules through symbiotic interaction with specialized soil bacteria. Legumes possess a highly plastic root system which modulates its architecture according to the nitrogen availability in the soil. Understanding how legumes regulate root development in response to nitrogen availability is an important step to improving root architecture. The nitrogen-mediated root development pathway starts with sensing soil nitrogen level followed by subsequent signal transduction pathways involving phytohormones, microRNAs and regulatory peptides that collectively modulate the growth and shape of the root system. This review focuses on the current understanding of nitrogen-mediated legume root architecture including local and systemic regulations by different N-sources and the modulations by phytohormones and small regulatory molecules. PMID:24098303

  17. Regulation of cellular signals from nutritional molecules: a specific role for phytochemicals, beyond antioxidant activity.

    PubMed

    Virgili, Fabio; Marino, Maria

    2008-11-01

    Phytochemicals (PhC) are a ubiquitous class of plant secondary metabolites. A "recommended" human diet should warrant a high proportion of energy from fruits and vegetables, therefore providing, among other factors, a huge intake of PhC, in general considered "health promoting" by virtue of their antioxidant activity and positive modulation, either directly or indirectly, of the cellular and tissue redox balance. Diet acts through multiple pathways and the association between the consumption of specific food items and the risk of degenerative diseases is extremely complex. Recent literature suggests that molecules having a chemical structure compatible with a putative antioxidant capacity can actually "perform" activities and roles independent of such capacity, interacting with cellular functions at different levels, such as affecting enzyme activities, binding to membrane or nuclear receptors as either an elective ligand or a ligand mimic. Inductive or signaling effects may occur at concentrations much lower than that required for effective antioxidant activity. Therefore, the "antioxidant hypothesis" is to be considered in some cases an intellectual "shortcut" possibly biasing the real understanding of the molecular mechanisms underlying the beneficial effects of various classes of food items. In the past few years, many exciting new indications elucidating the mechanisms of polyphenols have been published. Here, we summarize the current knowledge of the mechanisms by which specific molecules of nutritional interest, and in particular polyphenols, play a role in cellular response and in preventing pathologies. In particular, their direct interaction with nuclear receptors and their ability to modulate the activity of key enzymes involved in cell signaling and antioxidant responses are presented and discussed. PMID:18762244

  18. Emergence of Hydrogen Sulfide as an Endogenous Gaseous Signaling Molecule in Cardiovascular Disease

    PubMed Central

    Polhemus, David J.; Lefer, David J.

    2014-01-01

    Long recognized as a malodorous and highly toxic gas, recent experimental studies have revealed that hydrogen sulfide (H2S) is produced enzymatically in all mammalian species including man and exerts a number of critical actions to promote cardiovascular homeostasis and health. During the past 15 years, scientists have determined that H2S is produced by three endogenous enzymes and exerts powerful effects on endothelial cells, smooth muscle cells, inflammatory cells, mitochondria, endoplasmic reticulum, and nuclear transcription factors. These effects have been reported in multiple organ systems and the vast majority of data clearly indicate that H2S produced by the endogenous enzymes exerts cytoprotective actions. Recent preclinical studies investigating cardiovascular diseases have demonstrated that the administration of physiological or pharmacological levels of H2S attenuates myocardial injury, protects blood vessels, limits inflammation, and regulates blood pressure. H2S has emerged as a critical cardiovascular signaling molecule similar to nitric oxide (NO) and carbon monoxide (CO) with a profound impact on the heart and circulation (Figure 1). Our improved understanding of how H2S elicits protective actions, coupled with the very rapid development of novel H2S releasing agents, has resulted in heightened enthusiasm for the clinical translation of this ephemeral gaseous molecule. This review will examine our current state of knowledge regarding the actions of H2S within the cardiovascular system with an emphasis on the therapeutic potential and molecular crosstalk between H2S, NO, and CO. PMID:24526678

  19. Single-Molecule Microscopy Reveals Plasma Membrane Microdomains Created by Protein-Protein Networks that Exclude or Trap Signaling Molecules in T Cells

    PubMed Central

    Douglass, Adam D.; Vale, Ronald D.

    2010-01-01

    Summary Membrane subdomains have been implicated in T cell signaling, although their properties and mechanisms of formation remain controversial. Here, we have used single-molecule and scanning confocal imaging to characterize the behavior of GFP-tagged signaling proteins in Jurkat T cells. We show that the coreceptor CD2, the adaptor protein LAT, and tyrosine kinase Lck cocluster in discrete microdomains in the plasma membrane of signaling T cells. These microdomains require protein-protein interactions mediated through phosphorylation of LAT and are not maintained by interactions with actin or lipid rafts. Using a two color imaging approach that allows tracking of single molecules relative to the CD2/LAT/Lck clusters, we demonstrate that these microdomains exclude and limit the free diffusion of molecules in the membrane but also can trap and immobilize specific proteins. Our data suggest that diffusional trapping through protein-protein interactions creates microdomains that concentrate or exclude cell surface proteins to facilitate T cell signaling. PMID:15960980

  20. Protective effect of bioflavonoid myricetin enhances carbohydrate metabolic enzymes and insulin signaling molecules in streptozotocin–cadmium induced diabetic nephrotoxic rats

    SciTech Connect

    Kandasamy, Neelamegam; Ashokkumar, Natarajan

    2014-09-01

    Diabetic nephropathy is the kidney disease that occurs as a result of diabetes. The present study was aimed to evaluate the therapeutic potential of myricetin by assaying the activities of key enzymes of carbohydrate metabolism, insulin signaling molecules and renal function markers in streptozotocin (STZ)–cadmium (Cd) induced diabetic nephrotoxic rats. After myricetin treatment schedule, blood and tissue samples were collected to determine plasma glucose, insulin, hemoglobin, glycosylated hemoglobin and renal function markers, carbohydrate metabolic enzymes in the liver and insulin signaling molecules in the pancreas and skeletal muscle. A significant increase of plasma glucose, glycosylated hemoglobin, urea, uric acid, creatinine, blood urea nitrogen (BUN), urinary albumin, glycogen phosphorylase, glucose-6-phosphatase, and fructose-1,6-bisphosphatase and a significant decrease of plasma insulin, hemoglobin, hexokinase, glucose-6-phosphate dehydrogenase, glycogen and glycogen synthase with insulin signaling molecule expression were found in the STZ–Cd induced diabetic nephrotoxic rats. The administration of myricetin significantly normalizes the carbohydrate metabolic products like glucose, glycated hemoglobin, glycogen phosphorylase and gluconeogenic enzymes and renal function markers with increase insulin, glycogen, glycogen synthase and insulin signaling molecule expression like glucose transporter-2 (GLUT-2), glucose transporter-4 (GLUT-4), insulin receptor-1 (IRS-1), insulin receptor-2 (IRS-2) and protein kinase B (PKB). Based on the data, the protective effect of myricetin was confirmed by its histological annotation of the pancreas, liver and kidney tissues. These findings suggest that myricetin improved carbohydrate metabolism which subsequently enhances glucose utilization and renal function in STZ–Cd induced diabetic nephrotoxic rats. - Highlights: • Diabetic rats are more susceptible to cadmium nephrotoxicity. • Cadmium plays as a cumulative

  1. Abscisic acid perception and signaling transduction in strawberry

    PubMed Central

    Li, Chunli; Jia, Haifeng; Chai, Yemao; Shen, Yuanyue

    2011-01-01

    On basis of fruit differential respiration and ethylene effects, climacteric and non-climacteric fruits have been classically defined. Over the past decades, the molecular mechanisms of climacteric fruit ripening were abundantly described and found to focus on ethylene perception and signaling transduction. In contrast, until our most recent breakthroughs, much progress has been made toward understanding the signaling perception and transduction mechanisms for abscisic acid (ABA) in strawberry, a model for non-climacteric fruit ripening. Our reports not only have provided several lines of strong evidences for ABA-regulated ripening of strawberry fruit, but also have demonstrated that homology proteins of Arabidopsis ABA receptors, including PYR/PYL/RCAR and ABAR/CHLH, act as positive regulators of ripening in response to ABA. These receptors also trigger a set of ABA downstream signaling components, and determine significant changes in the expression levels of both sugar and pigment metabolism-related genes that are closely associated with ripening. Soluble sugars, especially sucrose, may act as a signal molecular to trigger ABA accumulation through an enzymatic action of 9-cis-epoxycarotenoid dioxygenase 1 (FaNCED1). This mini-review offers an overview of these processes and also outlines the possible, molecular mechanisms for ABA in the regulation of strawberry fruit ripening through the ABA receptors. PMID:22095148

  2. Evolution of Abscisic Acid Synthesis and Signaling Mechanisms

    PubMed Central

    Hauser, Felix; Waadt, Rainer; Schroeder, Julian I.

    2011-01-01

    The plant hormone abscisic acid (ABA) mediates seed dormancy, controls seedling development and triggers tolerance to abiotic stresses, including drought. Core ABA signaling components consist of a recently identified group of ABA receptor proteins of the PYRABACTIN RESISTANCE (PYR)/REGULATORY COMPONENT OF ABA RECEPTOR (RCAR) family that act as negative regulators of members of the PROTEIN PHOSPHATASE 2C (PP2C) family. Inhibition of PP2C activity enables activation of SNF1-RELATED KINASE 2 (SnRK2) protein kinases, which target downstream components, including transcription factors, ion channels and NADPH oxidases. These and other components form a complex ABA signaling network. Here, an in depth analysis of the evolution of components in this ABA signaling network shows that (i) PYR/RCAR ABA receptor and ABF-type transcription factor families arose during land colonization of plants and are not found in algae and other species, (ii) ABA biosynthesis enzymes have evolved to plant- and fungal-specific forms, leading to different ABA synthesis pathways, (iii) existing stress signaling components, including PP2C phosphatases and SnRK kinases, were adapted for novel roles in this plant-specific network to respond to water limitation. In addition, evolutionarily conserved secondary structures in the PYR/RCAR ABA receptor family are visualized. PMID:21549957

  3. Signaling lymphocytic activation molecule (CDw150) is homophilic but self-associates with very low affinity.

    PubMed

    Mavaddat, N; Mason, D W; Atkinson, P D; Evans, E J; Gilbert, R J; Stuart, D I; Fennelly, J A; Barclay, A N; Davis, S J; Brown, M H

    2000-09-01

    Signaling lymphocytic activating molecule ((SLAM) CDw150) is a glycoprotein that belongs to the CD2 subset of the immunoglobulin superfamily and is expressed on the surface of activated T- and B-cells. It has been proposed that SLAM is homophilic and required for bidirectional signaling during T- and B-cell activation. Previous work has suggested that the affinity of SLAM self-association might be unusually high, undermining the concept that protein interactions mediating transient cell-cell contacts, such as those involving leukocytes, have to be weak in order that such contacts are readily reversible. Using surface plasmon resonance-based methods and analytical ultracentrifugation (AUC), we confirm that SLAM is homophilic. However, we also establish a new theoretical treatment of surface plasmon resonance-derived homophilic binding data, which indicates that SLAM-SLAM interactions (solution K(d) approximately 200 micrometer) are in fact considerably weaker than most other well characterized protein-protein interactions at the cell surface (solution K(d) approximately 0.4-20 micrometer), a conclusion that is supported by the AUC analysis. Whereas further analysis of the AUC data imply that SLAM could form "head to head" dimers spanning adjacent cells, the very low affinity raises important questions regarding the physiological role and/or properties of such interactions. PMID:10831600

  4. Is insulin signaling molecules misguided in diabetes for ubiquitin-proteasome mediated degradation?

    PubMed

    Balasubramanyam, Muthuswamy; Sampathkumar, Rangasamy; Mohan, Viswanathan

    2005-07-01

    Recent mining of the human and mouse genomes, use of yeast genetics, and detailed analyses of several biochemical pathways, have resulted in the identification of many new roles for ubiquitin-proteasome mediated degradation of proteins. In the context of last year's award of Noble Prize (Chemistry) work, the ubiquitin and ubiquitin-like modifications are increasingly recognized as key regulatory events in health and disease. Although the ATP-dependent ubiquitin-proteasome system has evolved as premier cellular proteolytic machinery, dysregulation of this system by several different mechanisms leads to inappropriate degradation of specific proteins and pathological consequences. While aberrations in the ubiquitin-proteasome pathway have been implicated in certain malignancies and neurodegenerative disorders, recent studies indicate a role for this system in the pathogenesis of diabetes and its complications. Inappropriate degradation of insulin signaling molecules such as insulin receptor substrates (IRS-1 and IRS-2) has been demonstrated in experimental diabetes, mediated in part through the up-regulation of suppressors of cytokine signaling (SOCS). It appears that altered ubiquitin-proteasome system might be one of the molecular mechanisms of insulin resistance in many pathological situations. Drugs that modulate the SOCS action and/or proteasomal degradation of proteins could become novel agents for the treatment of insulin resistance and Type 2 diabetes. PMID:16335791

  5. Extracellular signalling molecules in the ischaemic/reperfused heart – druggable and translatable for cardioprotection?

    PubMed Central

    Kleinbongard, P; Heusch, G

    2015-01-01

    In patients with acute myocardial infarction, timely reperfusion is essential to limit infarct size. However, reperfusion also adds to myocardial injury. Brief episodes of ischaemia/reperfusion in the myocardium or on organ remote from the heart, before or shortly after sustained myocardial ischaemia effectively reduce infarct size, provided there is eventual reperfusion. Such conditioning phenomena have been established in many experimental studies and also translated to humans. The underlying signal transduction, that is the molecular identity of triggers, mediators and effectors, is not clear yet in detail, but several extracellular signalling molecules, such as adenosine, bradykinin and opioids, have been identified to contribute to cardioprotection by conditioning manoeuvres. Several trials have attempted the translation of cardioprotection by such autacoids into a clinical scenario of myocardial ischaemia and reperfusion. Adenosine and its selective agonists reduced infarct size in a few studies, but this benefit was not translated into improved clinical outcome. All studies with bradykinin or drugs which increase bradykinin's bioavailability reported reduced infarct size and some of them also improved clinical outcome. Synthetic opioid agonists did not result in a robust infarct size reduction, but this failure of translation may relate to the cardioprotective properties of the underlying anaesthesia per se or of the comparator drugs. The translation of findings in healthy, young animals with acute coronary occlusion/reperfusion to patients of older age, with a variety of co-morbidities and co-medications, suffering from different scenarios of myocardial ischaemia/reperfusion remains a challenge. PMID:25204973

  6. Regulation of ITAM adaptor molecules and their receptors by inhibition of calcineurin-NFAT signalling during late stage osteoclast differentiation

    SciTech Connect

    Zawawi, M.S.F.; Dharmapatni, A.A.S.S.K.; Cantley, M.D.; McHugh, K.P.; Haynes, D.R.; Crotti, T.N.

    2012-10-19

    Highlights: Black-Right-Pointing-Pointer Calcineurin/NFAT inhibitors FK506 and VIVIT treated human PBMC derived osteoclasts in vitro. Black-Right-Pointing-Pointer Differential regulation of ITAM receptors and adaptor molecules by calcineurin/NFAT inhibitors. Black-Right-Pointing-Pointer FK506 and VIVIT suppress ITAM factors during late phase osteoclast differentiation. -- Abstract: Osteoclasts are specialised bone resorptive cells responsible for both physiological and pathological bone loss. Osteoclast differentiation and activity is dependent upon receptor activator NF-kappa-B ligand (RANKL) interacting with its receptor RANK to induce the transcription factor, nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1). The immunoreceptor tyrosine-based activation motif (ITAM)-dependent pathway has been identified as a co-stimulatory pathway in osteoclasts. Osteoclast-associated receptor (OSCAR) and triggering receptor expressed in myeloid cells (TREM2) are essential receptors that pair with adaptor molecules Fc receptor common gamma chain (FcR{gamma}) and DNAX-activating protein 12 kDa (DAP12) respectively to induce calcium signalling. Treatment with calcineurin-NFAT inhibitors, Tacrolimus (FK506) and the 11R-VIVIT (VIVIT) peptide, reduces NFATc1 expression consistent with a reduction in osteoclast differentiation and activity. This study aimed to investigate the effects of inhibiting calcineurin-NFAT signalling on the expression of ITAM factors and late stage osteoclast genes including cathepsin K (CathK), Beta 3 integrin ({beta}3) and Annexin VIII (AnnVIII). Human peripheral blood mononuclear cells (PBMCs) were differentiated with RANKL and macrophage-colony stimulating factor (M-CSF) over 10 days in the presence or absence of FK506 or VIVIT. Osteoclast formation (as assessed by tartrate resistant acid phosphatase (TRAP)) and activity (assessed by dentine pit resorption) were significantly reduced with treatment. Quantitative real

  7. On the influence of low-energy ionizing radiation on the amino acid molecule: proline

    NASA Astrophysics Data System (ADS)

    Tamuliene, Jelena; Romanova, Liudmila; Vukstich, Vasyl; Papp, Alexander; Shkurin, Serhiy; Baliulyte, Laura; Snegursky, Alexander

    2016-06-01

    New data on the electron-impact fragmentation of the amino acid proline molecule are presented as being related to the formation of the ionized products due to the influence of low-energy ionizing radiation on the above molecule. An extensive DFT-theory based on the theoretical approach enabled the main pathways of the proline molecules fragmentation to be elucidated. A series of the produced fragments have been identified. The absolute appearance energies for some of them have been both measured experimentally and calculated theoretically. The data of the experimental studies and theoretical calculations are compared and analyzed. Contribution to the Topical Issue "Low-Energy Interactions related to Atmospheric and Extreme Conditions", edited by S. Ptasinska, M. Smialek-Telega, A. Milosavljevic, B. Sivaraman.

  8. Convergence of Nitric Oxide and Lipid Signaling: Anti-Inflammatory Nitro-Fatty Acids

    PubMed Central

    Baker, Paul R.S.; Schopfer, Francisco J.; O’Donnell, Valerie B.; Freeman, Bruce A.

    2009-01-01

    The signaling mediators nitric oxide (·NO) and oxidized lipids, once viewed to transduce metabolic and inflammatory information via discrete and independent pathways, are now appreciated as interdependent regulators of immune response and metabolic homeostasis. The interactions between these two classes of mediators result in reciprocal control of mediator sythesis that is strongly influenced by the local chemical environment. The relationship between the two pathways extends beyond co-regulation of ·NO and eicosanoid formation to converge via the nitration of unsaturated fatty acids to yield nitro derivatives (NO2-FA). These pluripotent signaling molecules are generated in vivo as an adaptive response to oxidative inflammatory conditions and manifest predominantly anti-inflammatory signaling reactions. These actions of NO2-FA are diverse, with these species serving as a potential chemical reserve of ·NO, reacting with cellular nucleophiles to post-translationally modify protein structure, function and localization. In this regard these species act as potent endogenous ligands for peroxisome proliferator activated receptor γ. Functional consequences of these signaling mechanisms have been shown in multiple model systems, including the inhibition of platelet and neutrophil functions, induction of heme oxygenase-1, inhibition of LPS-induced cytokine release in monocytes, increased insulin sensitivity and glucose uptake in adipocytes and relaxation of pre-constricted rat aortic segments. These observations have propelled further in vitro and in vivo studies of mechanisms of NO2-FA signaling and metabolism, highlighting the therapeutic potential of this class of molecules as anti-inflammatory drug candidates. PMID:19200454

  9. Jasmonic acid is a crucial signal transducer in heat shock induced sesquiterpene formation in Aquilaria sinensis

    PubMed Central

    Xu, Yan-Hong; Liao, Yong-Cui; Zhang, Zheng; Liu, Juan; Sun, Pei-Wen; Gao, Zhi-Hui; Sui, Chun; Wei, Jian-He

    2016-01-01

    Agarwood, a highly valuable resinous and fragrant heartwood of Aquilaria plants, is widely used in traditional medicines, incense and perfume. Only when Aquilaria trees are wounded by external stimuli do they form agarwood sesquiterpene defensive compounds. Therefore, understanding the signaling pathway of wound-induced agarwood formation is important. Jasmonic acid (JA) is a well-characterized molecule that mediates a plant’s defense response and secondary metabolism. However, little is known about the function of endogenous JA in agarwood sesquiterpene biosynthesis. Here, we report that heat shock can up-regulate the expression of genes in JA signaling pathway, induce JA production and the accumulation of agarwood sesquiterpene in A. sinensis cell suspension cultures. A specific inhibitor of JA, nordihydroguaiaretic acid (NDGA), could block the JA signaling pathway and reduce the accumulation of sesquiterpene compounds. Additionally, compared to SA and H2O2, exogenously supplied methyl jasmonate has the strongest stimulation effect on the production of sesquiterpene compounds. These results clearly demonstrate the central induction role of JA in heat-shock-induced sesquiterpene production in A. sinensis. PMID:26902148

  10. Jasmonic acid is a crucial signal transducer in heat shock induced sesquiterpene formation in Aquilaria sinensis.

    PubMed

    Xu, Yan-Hong; Liao, Yong-Cui; Zhang, Zheng; Liu, Juan; Sun, Pei-Wen; Gao, Zhi-Hui; Sui, Chun; Wei, Jian-He

    2016-01-01

    Agarwood, a highly valuable resinous and fragrant heartwood of Aquilaria plants, is widely used in traditional medicines, incense and perfume. Only when Aquilaria trees are wounded by external stimuli do they form agarwood sesquiterpene defensive compounds. Therefore, understanding the signaling pathway of wound-induced agarwood formation is important. Jasmonic acid (JA) is a well-characterized molecule that mediates a plant's defense response and secondary metabolism. However, little is known about the function of endogenous JA in agarwood sesquiterpene biosynthesis. Here, we report that heat shock can up-regulate the expression of genes in JA signaling pathway, induce JA production and the accumulation of agarwood sesquiterpene in A. sinensis cell suspension cultures. A specific inhibitor of JA, nordihydroguaiaretic acid (NDGA), could block the JA signaling pathway and reduce the accumulation of sesquiterpene compounds. Additionally, compared to SA and H2O2, exogenously supplied methyl jasmonate has the strongest stimulation effect on the production of sesquiterpene compounds. These results clearly demonstrate the central induction role of JA in heat-shock-induced sesquiterpene production in A. sinensis. PMID:26902148

  11. Sequential photochemical and microbial degradation of organic molecules bound to humic acid

    SciTech Connect

    Amador, J.A.; Zika, R.G. ); Alexander, M. )

    1989-11-01

    We studied the effects of photochemical processes on the mineralization by soil microorganisms of (2-{sup 14}C)glycine bound to soil humic acid. Microbial mineralization of these complexes in the dark increased inversely with the molecular weight of the complex molecules. Sunlight irradiation of glycine-humic acid complexes resulted in loss of absorbance in the UV range and an increase in the amount of {sup 14}C-labeled low-molecular-weight photoproducts and the rate and extent of mineralization. More than half of the radioactivity in the low-molecular-weight photoproducts appears to be associated with carboxylic acids. Microbial mineralization of the organic carbon increased with solar flux and was proportional to the loss of A{sub 330}. Mineralization was proportional to the percentage of the original complex that was converted to low-molecular-weight photoproducts. Only light at wavelengths below 380 nm had an effect on the molecular weight distribution of the products formed from the glycine-humic acid complexes and on the subsequent microbial mineralization. Our results indicate that photochemical processes generate low-molecular-weight, readily biodegradable molecules from high-molecular-weight complexes of glycine with humic acid.

  12. Sequential photochemical and microbial degradation of organic molecules bound to humic Acid.

    PubMed

    Amador, J A; Alexander, M; Zika, R G

    1989-11-01

    We studied the effects of photochemical processes on the mineralization by soil microorganisms of [2-C]glycine bound to soil humic acid. Microbial mineralization of these complexes in the dark increased inversely with the molecular weight of the complex molecules. Sunlight irradiation of glycine-humic acid complexes resulted in loss of absorbance in the UV range and an increase in the amount of C-labeled low-molecular-weight photoproducts and the rate and extent of mineralization. More than half of the radioactivity in the low-molecular-weight photoproducts appears to be associated with carboxylic acids. Microbial mineralization of the organic carbon increased with solar flux and was proportional to the loss of A(330). Mineralization was proportional to the percentage of the original complex that was converted to low-molecular-weight photoproducts. Only light at wavelengths below 380 nm had an effect on the molecular weight distribution of the products formed from the glycine-humic acid complexes and on the subsequent microbial mineralization. Our results indicate that photochemical processes generate low-molecular-weight, readily biodegradable molecules from high-molecular-weight complexes of glycine with humic acid. PMID:16348046

  13. Sequential Photochemical and Microbial Degradation of Organic Molecules Bound to Humic Acid

    PubMed Central

    Amador, José A.; Alexander, Martin; Zika, Rod G.

    1989-01-01

    We studied the effects of photochemical processes on the mineralization by soil microorganisms of [2-14C]glycine bound to soil humic acid. Microbial mineralization of these complexes in the dark increased inversely with the molecular weight of the complex molecules. Sunlight irradiation of glycine-humic acid complexes resulted in loss of absorbance in the UV range and an increase in the amount of 14C-labeled low-molecular-weight photoproducts and the rate and extent of mineralization. More than half of the radioactivity in the low-molecular-weight photoproducts appears to be associated with carboxylic acids. Microbial mineralization of the organic carbon increased with solar flux and was proportional to the loss of A330. Mineralization was proportional to the percentage of the original complex that was converted to low-molecular-weight photoproducts. Only light at wavelengths below 380 nm had an effect on the molecular weight distribution of the products formed from the glycine-humic acid complexes and on the subsequent microbial mineralization. Our results indicate that photochemical processes generate low-molecular-weight, readily biodegradable molecules from high-molecular-weight complexes of glycine with humic acid. PMID:16348046

  14. Omega-3 fatty acids, lipid rafts, and T cell signaling.

    PubMed

    Hou, Tim Y; McMurray, David N; Chapkin, Robert S

    2016-08-15

    n-3 polyunsaturated fatty acids (PUFA) have been shown in many clinical studies to attenuate inflammatory responses. Although inflammatory responses are orchestrated by a wide spectrum of cells, CD4(+) T cells play an important role in the etiology of many chronic inflammatory diseases such as inflammatory bowel disease and obesity. In light of recent concerns over the safety profiles of non-steroidal anti-inflammatory drugs (NSAIDs), alternatives such as bioactive nutraceuticals are becoming more attractive. In order for these agents to be accepted into mainstream medicine, however, the mechanisms by which nutraceuticals such as n-3 PUFA exert their anti-inflammatory effects must be fully elucidated. Lipid rafts are nanoscale, dynamic domains in the plasma membrane that are formed through favorable lipid-lipid (cholesterol, sphingolipids, and saturated fatty acids) and lipid-protein (membrane-actin cytoskeleton) interactions. These domains optimize the clustering of signaling proteins at the membrane to facilitate efficient cell signaling which is required for CD4(+) T cell activation and differentiation. This review summarizes novel emerging data documenting the ability of n-3 PUFA to perturb membrane-cytoskeletal structure and function in CD4(+) T cells. An understanding of these underlying mechanisms will provide a rationale for the use of n-3 PUFA in the treatment of chronic inflammation. PMID:26001374

  15. Single Molecule Spectroscopy of Amino Acids and Peptides by Recognition Tunneling

    PubMed Central

    Zhao, Yanan; Ashcroft, Brian; Zhang, Peiming; Liu, Hao; Sen, Suman; Song, Weisi; Im, JongOne; Gyarfas, Brett; Manna, Saikat; Biswas, Sovan; Borges, Chad; Lindsay, Stuart

    2014-01-01

    The human proteome has millions of protein variants due to alternative RNA splicing and post-translational modifications, and variants that are related to diseases are frequently present in minute concentrations. For DNA and RNA, low concentrations can be amplified using the polymerase chain reaction, but there is no such reaction for proteins. Therefore, the development of single molecule protein sequencing is a critical step in the search for protein biomarkers. Here we show that single amino acids can be identified by trapping the molecules between two electrodes that are coated with a layer of recognition molecules and measuring the electron tunneling current across the junction. A given molecule can bind in more than one way in the junction, and we therefore use a machine-learning algorithm to distinguish between the sets of electronic ‘fingerprints’ associated with each binding motif. With this recognition tunneling technique, we are able to identify D, L enantiomers, a methylated amino acid, isobaric isomers, and short peptides. The results suggest that direct electronic sequencing of single proteins could be possible by sequentially measuring the products of processive exopeptidase digestion, or by using a molecular motor to pull proteins through a tunnel junction integrated with a nanopore. PMID:24705512

  16. Single-molecule spectroscopy of amino acids and peptides by recognition tunnelling.

    PubMed

    Zhao, Yanan; Ashcroft, Brian; Zhang, Peiming; Liu, Hao; Sen, Suman; Song, Weisi; Im, JongOne; Gyarfas, Brett; Manna, Saikat; Biswas, Sovan; Borges, Chad; Lindsay, Stuart

    2014-06-01

    The human proteome has millions of protein variants due to alternative RNA splicing and post-translational modifications, and variants that are related to diseases are frequently present in minute concentrations. For DNA and RNA, low concentrations can be amplified using the polymerase chain reaction, but there is no such reaction for proteins. Therefore, the development of single-molecule protein sequencing is a critical step in the search for protein biomarkers. Here, we show that single amino acids can be identified by trapping the molecules between two electrodes that are coated with a layer of recognition molecules, then measuring the electron tunnelling current across the junction. A given molecule can bind in more than one way in the junction, and we therefore use a machine-learning algorithm to distinguish between the sets of electronic 'fingerprints' associated with each binding motif. With this recognition tunnelling technique, we are able to identify D and L enantiomers, a methylated amino acid, isobaric isomers and short peptides. The results suggest that direct electronic sequencing of single proteins could be possible by sequentially measuring the products of processive exopeptidase digestion, or by using a molecular motor to pull proteins through a tunnel junction integrated with a nanopore. PMID:24705512

  17. Single-molecule spectroscopy of amino acids and peptides by recognition tunnelling

    NASA Astrophysics Data System (ADS)

    Zhao, Yanan; Ashcroft, Brian; Zhang, Peiming; Liu, Hao; Sen, Suman; Song, Weisi; Im, Jongone; Gyarfas, Brett; Manna, Saikat; Biswas, Sovan; Borges, Chad; Lindsay, Stuart

    2014-06-01

    The human proteome has millions of protein variants due to alternative RNA splicing and post-translational modifications, and variants that are related to diseases are frequently present in minute concentrations. For DNA and RNA, low concentrations can be amplified using the polymerase chain reaction, but there is no such reaction for proteins. Therefore, the development of single-molecule protein sequencing is a critical step in the search for protein biomarkers. Here, we show that single amino acids can be identified by trapping the molecules between two electrodes that are coated with a layer of recognition molecules, then measuring the electron tunnelling current across the junction. A given molecule can bind in more than one way in the junction, and we therefore use a machine-learning algorithm to distinguish between the sets of electronic `fingerprints' associated with each binding motif. With this recognition tunnelling technique, we are able to identify D and L enantiomers, a methylated amino acid, isobaric isomers and short peptides. The results suggest that direct electronic sequencing of single proteins could be possible by sequentially measuring the products of processive exopeptidase digestion, or by using a molecular motor to pull proteins through a tunnel junction integrated with a nanopore.

  18. Nucleic acid molecules conferring enhanced ethanol tolerance and microorganisms having enhanced tolerance to ethanol

    DOEpatents

    Brown, Steven; Guss, Adam; Yang, Shihui; Karpinets, Tatiana; Lynd, Lee; Shao, Xiongjun

    2014-01-14

    The present invention provides isolated nucleic acid molecules which encode a mutant acetaldehyde-CoA/alcohol dehydrogenase or mutant alcohol dehydrogenase and confer enhanced tolerance to ethanol. The invention also provides related expression vectors, genetically engineered microorganisms having enhanced tolerance to ethanol, as well as methods of making and using such genetically modified microorganisms for production of biofuels based on fermentation of biomass materials.

  19. AI-2 signalling is induced by acidic shock in probiotic strains of Lactobacillus spp.

    PubMed

    Moslehi-Jenabian, Saloomeh; Gori, Klaus; Jespersen, Lene

    2009-11-15

    Survival and ability to respond to various environmental stresses such as low pH are important factors for lactobacilli for their function as probiotics. LuxS-mediated quorum sensing mechanism, which is based on the production of universal signal molecule called autoinducer-2 (AI-2), regulates important physiological traits and a variety of adaptive processes in different bacteria. The aim of this study was to investigate the effect of acidic stress on LuxS-mediated quorum sensing (AI-2 signalling) in four probiotic strains of different Lactobacillus species. Initially, the production of AI-2-like molecule was investigated in four strains of Lactobacillus spp. at standard growth conditions using Vibrio harveyi bioluminescence assay. Species variation in AI-2 activity was observed. AI-2 activity started at early-exponential growth phase and increased during the mid-exponential phase concomitant with the reduction of pH, reaching maximum at late exponential phase (L. rhamnosus GG) or at stationary phase (L. salivarius UCC118, L. acidophilus NCFM and L. johnsonii NCC533). Acidic shock experiments were conducted on L. rhamnosus GG and L. acidophilus NCFM after exposure to different acidic shocks (pH 5.0, 4.0 and 3.0) and to pH 6.5 as control, measuring AI-2 activity and transcription of the luxS gene. AI-2 activity increased by lowering the pH in a dose dependent manner and was negatively influenced by acid adaptation. In both species, the luxS gene was repressed after exposure to pH 6.5 as control. However, after acidic shock (pH 4.0) a transient response of luxS gene was observed and the transcription augmented over time, reaching a maximum level and decreased subsequently. Acid adaptation of cells attenuated the transcription of this gene. Based on the observations done in the present study, the luxS gene appears to have a clear role in acidic stress response in probiotic lactobacilli. This might be important in the survival of these bacteria during the passage

  20. Investigating organic molecules responsible of auxin-like activity of humic acid fraction extracted from vermicompost.

    PubMed

    Scaglia, Barbara; Nunes, Ramom Rachide; Rezende, Maria Olímpia Oliveira; Tambone, Fulvia; Adani, Fabrizio

    2016-08-15

    This work studied the auxin-like activity of humic acids (HA) obtained from vermicomposts produced using leather wastes plus cattle dung at different maturation stages (fresh, stable and mature). Bioassays were performed by testing HA concentrations in the range of 100-6000mgcarbonL(-1). (13)C CPMAS-NMR and GC-MS instrumental methods were used to assess the effect of biological processes and starting organic mixtures on HA composition. Not all HAs showed IAA-like activity and in general, IAA-like activity increased with the length of the vermicomposting process. The presence of leather wastes was not necessary to produce the auxin-like activity of HA, since HA extracted from a mix of cattle manure and sawdust, where no leather waste was added, showed IAA-like activity as well. CPMAS (13)CNMR revealed that HAs were similar independently of the mix used and that the humification process involved the increasing concentration of pre-existing alkali soluble fractions in the biomass. GC/MS allowed the identification of the molecules involved in IAA-like effects: carboxylic acids and amino acids. The concentration of active molecules, rather than their simple presence in HA, determined the bio-stimulating effect, and a good linear regression between auxin-like activity and active stimulating molecules concentration was found (R(2)=-0.85; p<0.01, n=6). PMID:27100009

  1. Effects of omega-3 and omega-6 fatty acids on IGF-I receptor signalling in colorectal cancer cells.

    PubMed

    Seti, Hila; Leikin-Frenkel, Alicia; Werner, Haim

    2009-07-01

    The insulin-like growth factor (IGF) system plays a critical role in normal growth and development as well as in malignant states. Most of the biological activities of the IGFs are mediated by the IGF-IR, which is over-expressed in most tumours and cancer cell lines. Fatty acids have critical roles in both systemic physiological processes (e.g. metabolism) and cellular events (e.g. proliferation, apoptosis, signal transduction, and gene expression). Alpha-linolenic acid (ALA) and linoleic acid (LA) are essential fatty acids of the omega-3 and omega-6 families, respectively. The aim of this study was to investigate the potential interactions between fatty acids and the IGF signal transduction pathways, and to evaluate the impact of this interplay on colon cancer cells survival and proliferation. Results of Western blot analyses revealed that ALA and LA enhanced the ligand-induced IGF-IR phosphorylation and, in addition, increased receptor phosphorylation in an IGF-I independent manner. Furthermore, fatty acid treatment led to phosphorylation of downstream signalling molecules, including Akt and Erk. In addition, FACS analysis and apoptosis measurements indicated that ALA and LA have a potential mitogenic effect on HCT116 cells, as reflected by the number of cells in S phase and by a reduction of PARP cleavage, implying a reduction in apoptotic activity. In summary, our results provide evidence that omega-3 and omega-6 fatty acids modulate IGF-I action in colon cancer cells. PMID:19480565

  2. Impact of a Cross-Kingdom Signaling Molecule of Candida albicans on Acinetobacter baumannii Physiology

    PubMed Central

    Kostoulias, Xenia; Murray, Gerald L.; Cerqueira, Gustavo M.; Kong, Jason B.; Bantun, Farkad; Mylonakis, Eleftherios; Khoo, Chen Ai

    2015-01-01

    Multidrug-resistant (MDR) Acinetobacter baumannii is an opportunistic human pathogen that has become highly problematic in the clinical environment. Novel therapies are desperately required. To assist in identifying new therapeutic targets, the antagonistic interactions between A. baumannii and the most common human fungal pathogen, Candida albicans, were studied. We have observed that the C. albicans quorum-sensing molecule, farnesol, has cross-kingdom interactions, affecting the viability of A. baumannii. To gain an understanding of its mechanism, the transcriptional profile of A. baumannii exposed to farnesol was examined. Farnesol caused dysregulation of a large number of genes involved in cell membrane biogenesis, multidrug efflux pumps (AcrAB-like and AdeIJK-like), and A. baumannii virulence traits such as biofilm formation (csuA, csuB, and ompA) and motility (pilZ and pilH). We also observed a strong induction in genes involved in cell division (minD, minE, ftsK, ftsB, and ftsL). These transcriptional data were supported by functional assays showing that farnesol disrupts A. baumannii cell membrane integrity, alters cell morphology, and impairs virulence characteristics such as biofilm formation and twitching motility. Moreover, we showed that A. baumannii uses efflux pumps as a defense mechanism against this eukaryotic signaling molecule. Owing to its effects on membrane integrity, farnesol was tested to see if it potentiated the activity of the membrane-acting polymyxin antibiotic colistin. When coadministered, farnesol increased sensitivity to colistin for otherwise resistant strains. These data provide mechanistic understanding of the antagonistic interactions between diverse pathogens and may provide important insights into novel therapeutic strategies. PMID:26482299

  3. Nanopore Analysis of Nucleic Acids: Single-Molecule Studies of Molecular Dynamics, Structure, and Base Sequence

    NASA Astrophysics Data System (ADS)

    Olasagasti, Felix; Deamer, David W.

    Nucleic acids are linear polynucleotides in which each base is covalently linked to a pentose sugar and a phosphate group carrying a negative charge. If a pore having roughly the crosssectional diameter of a single-stranded nucleic acid is embedded in a thin membrane and a voltage of 100 mV or more is applied, individual nucleic acids in solution can be captured by the electrical field in the pore and translocated through by single-molecule electrophoresis. The dimensions of the pore cannot accommodate anything larger than a single strand, so each base in the molecule passes through the pore in strict linear sequence. The nucleic acid strand occupies a large fraction of the pore's volume during translocation and therefore produces a transient blockade of the ionic current created by the applied voltage. If it could be demonstrated that each nucleotide in the polymer produced a characteristic modulation of the ionic current during its passage through the nanopore, the sequence of current modulations would reflect the sequence of bases in the polymer. According to this basic concept, nanopores are analogous to a Coulter counter that detects nanoscopic molecules rather than microscopic [1,2]. However, the advantage of nanopores is that individual macromolecules can be characterized because different chemical and physical properties affect their passage through the pore. Because macromolecules can be captured in the pore as well as translocated, the nanopore can be used to detect individual functional complexes that form between a nucleic acid and an enzyme. No other technique has this capability.

  4. Lipoteichoic acid-deficient Lactobacillus acidophilus regulates downstream signals.

    PubMed

    Saber, Rana; Zadeh, Mojgan; Pakanati, Krishna C; Bere, Praveen; Klaenhammer, Todd; Mohamadzadeh, Mansour

    2011-03-01

    The trillions of microbes residing within the intestine induce critical signals that either regulate or stimulate host immunity via their bacterial products. To better understand the immune regulation elicited by lipoteichoic acid (LTA)-deficient Lactobacillus acidophilus NCFM in steady state and induced inflammation, we deleted phosphoglycerol transferase gene, which synthesizes LTA in L. acidophilus NCFM. In vitro and in vivo experiments were conducted in order to compare the immune regulatory properties of the L. acidophilus strain deficient in LTA (NCK2025) with its wild-type parent (NCK56) in C57BL/6, C57BL/6 recombination-activation gene 1-deficient (Rag1 (-/-)) and C57BL/6 Rag1(-/-)IL-10(-/-) mice. We demonstrate that NCK2025 significantly activates the phosphorylation of Erk1/2 but downregulates the phosphorylation of Akt1, cytosolic group IV PLA2 and p38 in mouse dendritic cells. Similarly, mice treated orally with NCK2025 exhibit decreased phosphorylation of inflammatory signals (Akt1, cytosolic group IV PLA2 or P38) but upregulate Erk1/2-phosphorylation in colonic epithelial cells in comparison with mice treated with NCK56. In addition, regulation of pathogenic CD4+ T cell induced colitis by NCK2025 was observed in Rag1 (-/-) but not Rag1(-/-)IL-10 (-/-) mice suggests a critical role of IL-10 that may be tightly regulated by Erk1/2 signaling. These data highlight the immunosuppressive properties of NCK2025 to deliver regulatory signals in innate cells, which results in the mitigation of T-cell-induced colitis in vivo. PMID:21395377

  5. Structure-based Discovery of Novel Small Molecule Wnt Signaling Inhibitors by Targeting the Cysteine-rich Domain of Frizzled*

    PubMed Central

    Lee, Ho-Jin; Bao, Ju; Miller, Ami; Zhang, Chi; Wu, Jibo; Baday, Yiressy C.; Guibao, Cristina; Li, Lin; Wu, Dianqing; Zheng, Jie J.

    2015-01-01

    Frizzled is the earliest discovered glycosylated Wnt protein receptor and is critical for the initiation of Wnt signaling. Antagonizing Frizzled is effective in inhibiting the growth of multiple tumor types. The extracellular N terminus of Frizzled contains a conserved cysteine-rich domain that directly interacts with Wnt ligands. Structure-based virtual screening and cell-based assays were used to identify five small molecules that can inhibit canonical Wnt signaling and have low IC50 values in the micromolar range. NMR experiments confirmed that these compounds specifically bind to the Wnt binding site on the Frizzled8 cysteine-rich domain with submicromolar dissociation constants. Our study confirms the feasibility of targeting the Frizzled cysteine-rich domain as an effective way of regulating canonical Wnt signaling. These small molecules can be further optimized into more potent therapeutic agents for regulating abnormal Wnt signaling by targeting Frizzled. PMID:26504084

  6. Identification of small molecule compounds that inhibit the HIF-1 signaling pathway

    PubMed Central

    2009-01-01

    Background Hypoxia-inducible factor-1 (HIF-1) is the major hypoxia-regulated transcription factor that regulates cellular responses to low oxygen environments. HIF-1 is composed of two subunits: hypoxia-inducible HIF-1α and constitutively-expressed HIF-1β. During hypoxic conditions, HIF-1α heterodimerizes with HIF-1β and translocates to the nucleus where the HIF-1 complex binds to the hypoxia-response element (HRE) and activates expression of target genes implicated in cell growth and survival. HIF-1α protein expression is elevated in many solid tumors, including those of the cervix and brain, where cells that are the greatest distance from blood vessels, and therefore the most hypoxic, express the highest levels of HIF-1α. Therapeutic blockade of the HIF-1 signaling pathway in cancer cells therefore provides an attractive strategy for development of anticancer drugs. To identify small molecule inhibitors of the HIF-1 pathway, we have developed a cell-based reporter gene assay and screened a large compound library by using a quantitative high-throughput screening (qHTS) approach. Results The assay is based upon a β-lactamase reporter under the control of a HRE. We have screened approximate 73,000 compounds by qHTS, with each compound tested over a range of seven to fifteen concentrations. After qHTS we have rapidly identified three novel structural series of HIF-1 pathway Inhibitors. Selected compounds in these series were also confirmed as inhibitors in a HRE β-lactamase reporter gene assay induced by low oxygen and in a VEGF secretion assay. Three of the four selected compounds tested showed significant inhibition of hypoxia-induced HIF-1α accumulation by western blot analysis. Conclusion The use of β-lactamase reporter gene assays, in combination with qHTS, enabled the rapid identification and prioritization of inhibitors specific to the hypoxia induced signaling pathway. PMID:20003191

  7. Basic Aspects of Tumor Cell Fatty Acid-Regulated Signaling and Transcription Factors

    PubMed Central

    Comba, Andrea; Lin, Yi-Hui; Eynard, Aldo Renato; Valentich, Mirta Ana; Fernandez-Zapico, Martin Ernesto; Pasqualini, Marìa Eugenia

    2012-01-01

    This article reviews the current knowledge and experimental research about the mechanisms by which fatty acids and their derivatives control specific gene expression involved during carcinogenesis. Changes in dietary fatty acids, specifically the polyunsaturated fatty acids (PUFAs) of the ω-3 and ω-6 families and some derived eicosanoids from lipoxygenases (LOXs), cyclooxygenases (COXs), and cytochrome P-450 (CYP-450), seem to control the activity of transcription factor families involved in cancer cell proliferation or cell death. Their regulation may be carried out either through direct binding to DNA as peroxisome proliferator–activated receptors (PPARs) or via modulation in an indirect manner of signaling pathway molecules (e.g., protein kinase C [PKC]) and other transcription factors (nuclear factor kappa B [NFκB] and sterol regulatory element binding protein [SREBP]). Knowledge of the mechanisms by which fatty acids control specific gene expression may identify important risk factors for cancer, and provide insight into the development of new therapeutic strategies for a better management of whole-body lipid metabolism. PMID:22048864

  8. Natural variation in small molecule-induced TIR-NB-LRR signaling induces root growth arrest via EDS1- and PAD4-complexed R protein VICTR in Arabidopsis.

    PubMed

    Kim, Tae-Houn; Kunz, Hans-Henning; Bhattacharjee, Saikat; Hauser, Felix; Park, Jiyoung; Engineer, Cawas; Liu, Amy; Ha, Tracy; Parker, Jane E; Gassmann, Walter; Schroeder, Julian I

    2012-12-01

    In a chemical genetics screen we identified the small-molecule [5-(3,4-dichlorophenyl)furan-2-yl]-piperidine-1-ylmethanethione (DFPM) that triggers rapid inhibition of early abscisic acid signal transduction via PHYTOALEXIN DEFICIENT4 (PAD4)- and ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1)-dependent immune signaling mechanisms. However, mechanisms upstream of EDS1 and PAD4 in DFPM-mediated signaling remain unknown. Here, we report that DFPM generates an Arabidopsis thaliana accession-specific root growth arrest in Columbia-0 (Col-0) plants. The genetic locus responsible for this natural variant, VICTR (VARIATION IN COMPOUND TRIGGERED ROOT growth response), encodes a TIR-NB-LRR (for Toll-Interleukin1 Receptor-nucleotide binding-Leucine-rich repeat) protein. Analyses of T-DNA insertion victr alleles showed that VICTR is necessary for DFPM-induced root growth arrest and inhibition of abscisic acid-induced stomatal closing. Transgenic expression of the Col-0 VICTR allele in DFPM-insensitive Arabidopsis accessions recapitulated the DFPM-induced root growth arrest. EDS1 and PAD4, both central regulators of basal resistance and effector-triggered immunity, as well as HSP90 chaperones and their cochaperones RAR1 and SGT1B, are required for the DFPM-induced root growth arrest. Salicylic acid and jasmonic acid signaling pathway components are dispensable. We further demonstrate that VICTR associates with EDS1 and PAD4 in a nuclear protein complex. These findings show a previously unexplored association between a TIR-NB-LRR protein and PAD4 and identify functions of plant immune signaling components in the regulation of root meristematic zone-targeted growth arrest. PMID:23275581

  9. Enhancement of Antiviral Immunity by Small Molecule Antagonist of Suppressor of Cytokine Signaling

    PubMed Central

    Ahmed, Chulbul M. I.; Dabelic, Rea; Martin, James P.; Jager, Lindsey D.; Haider, S. Mohammad; Johnson, Howard M.

    2011-01-01

    Suppressors of cytokine signaling (SOCSs) are negative regulators of both innate and adaptive immunity via inhibition of signaling by cytokines such as type I and type II IFNs. We have developed a small peptide antagonist of SOCS-1 that corresponds to the activation loop of JAK2. SOCS-1 inhibits both type I and type II IFN activities by binding to the kinase activation loop via the kinase inhibitory region of the SOCS. The antagonist, pJAK2(1001–1013), inhibited the replication of vaccinia virus and encephalomyocarditis virus in cell culture, suggesting that it possesses broad antiviral activity. In addition, pJAK2(1001–1013) protected mice against lethal vaccinia and encephalomyocarditis virus infection. pJAK2(1001–1013) increased the intracellular level of the constitutive IFN-β, which may play a role in the antagonist antiviral effect at the cellular level. Ab neutralization suggests that constitutive IFN-β may act intracellularly, consistent with recent findings on IFN-γ intracellular signaling. pJAK2(1001–1013) also synergizes with IFNs as per IFN-γ mimetic to exert a multiplicative antiviral effect at the level of transcription, the cell, and protection of mice against lethal viral infection. pJAK2(1001–1013) binds to the kinase inhibitory region of both SOCS-1 and SOCS-3 and blocks their inhibitory effects on the IFN-γ activation site promoter. In addition to a direct antiviral effect and synergism with IFN, the SOCS antagonist also exhibits adjuvant effects on humoral and cellular immunity as well as an enhancement of polyinosinic-polycytidylic acid activation of TLR3. The SOCS antagonist thus presents a novel and effective approach to enhancement of host defense against viruses. PMID:20543109

  10. Morbilliviruses Use Signaling Lymphocyte Activation Molecules (CD150) as Cellular Receptors

    PubMed Central

    Tatsuo, Hironobu; Ono, Nobuyuki; Yanagi, Yusuke

    2001-01-01

    Morbilliviruses comprise measles virus, canine distemper virus, rinderpest virus, and several other viruses that cause devastating human and animal diseases accompanied by severe immunosuppression and lymphopenia. Recently, we have shown that human signaling lymphocyte activation molecule (SLAM) is a cellular receptor for measles virus. In this study, we examined whether canine distemper and rinderpest viruses also use canine and bovine SLAMs, respectively, as cellular receptors. The Onderstepoort vaccine strain and two B95a (marmoset B cell line)-isolated strains of canine distemper virus caused extensive cytopathic effects in normally resistant CHO (Chinese hamster ovary) cells after expression of canine SLAM. The Ako vaccine strain of rinderpest virus produced strong cytopathic effects in bovine SLAM-expressing CHO cells. The data on entry with vesicular stomatitis virus pseudotypes bearing measles, canine distemper, or rinderpest virus envelope proteins were consistent with development of cytopathic effects in SLAM-expressing CHO cell clones after infection with the respective viruses, confirming that SLAM acts at the virus entry step (as a cellular receptor). Furthermore, most measles, canine distemper, and rinderpest virus strains examined could any use of the human, canine, and bovine SLAMs to infect cells. Our findings suggest that the use of SLAM as a cellular receptor may be a property common to most, if not all, morbilliviruses and explain the lymphotropism and immunosuppressive nature of morbilliviruses. PMID:11390585

  11. Cell Death-Associated Molecular-Pattern Molecules: Inflammatory Signaling and Control

    PubMed Central

    Sangiuliano, Beatriz; Pérez, Nancy Marcela; Moreira, Dayson F.; Belizário, José E.

    2014-01-01

    Apoptosis, necroptosis, and pyroptosis are different cellular death programs characterized in organs and tissues as consequence of microbes infection, cell stress, injury, and chemotherapeutics exposure. Dying and death cells release a variety of self-proteins and bioactive chemicals originated from cytosol, nucleus, endoplasmic reticulum, and mitochondria. These endogenous factors are named cell death-associated molecular-pattern (CDAMP), damage-associated molecular-pattern (DAMP) molecules, and alarmins. Some of them cooperate or act as important initial or delayed inflammatory mediators upon binding to diverse membrane and cytosolic receptors coupled to signaling pathways for the activation of the inflammasome platforms and NF-κB multiprotein complexes. Current studies show that the nonprotein thiols and thiol-regulating enzymes as well as highly diffusible prooxidant reactive oxygen and nitrogen species released together in extracellular inflammatory milieu play essential role in controlling pro- and anti-inflammatory activities of CDAMP/DAMP and alarmins. Here, we provide an overview of these emerging concepts and mechanisms of triggering and maintenance of tissue inflammation under massive death of cells. PMID:25140116

  12. Morphofunctional and signaling molecules overlap of the pineal gland and thymus: role and significance in aging.

    PubMed

    Paltsev, Michael A; Polyakova, Victoria O; Kvetnoy, Igor M; Anderson, George; Kvetnaia, Tatiana V; Linkova, Natalia S; Paltseva, Ekaterina M; Rubino, Rosa; De Cosmo, Salvatore; De Cata, Angelo; Mazzoccoli, Gianluigi

    2016-03-15

    Deficits in neuroendocrine-immune system functioning, including alterations in pineal and thymic glands, contribute to aging-associated diseases. This study looks at ageing-associated alterations in pineal and thymic gland functioning evaluating common signaling molecules present in both human and animal pinealocytes and thymocytes: endocrine cell markers (melatonin, serotonin, pCREB, AANAT, CGRP, VIP, chromogranin А); cell renovation markers (p53, AIF, Ki67), matrix metalloproteinases (MMP2, MMP9) and lymphocytes markers (CD4, CD5, CD8, CD20). Pineal melatonin is decreased, as is one of the melatonin pathway synthesis enzymes in the thymic gland. A further similarity is the increased MMPs levels evident over age in both glands. Significant differences are evident in cell renovation processes, which deteriorate more quickly in the aged thymus versus the pineal gland. Decreases in the number of pineal B-cells and thymic T-cells were also observed over aging. Collected data indicate that cellular involution of the pineal gland and thymus show many commonalities, but also significant changes in aging-associated proteins. It is proposed that such ageing-associated alterations in these two glands provide novel pharmaceutical targets for the wide array of medical conditions that are more likely to emerge over the course of ageing. PMID:26943046

  13. L1 CELL ADHESION MOLECULE SIGNALING IS INHIBITED BY ETHANOL IN VIVO

    PubMed Central

    Littner, Yoav; Tang, Ningfeng; He, Min; Bearer, Cynthia F.

    2012-01-01

    Background Fetal alcohol spectrum disorder is an immense public health problem. In vitro studies support the hypothesis that L1 cell adhesion molecule (L1) is a target for ethanol developmental neurotoxicity. L1 is critical for the development of the central nervous system. It functions through signal transduction leading to phosphorylation and dephosphorylation of tyrosines on its cytoplasmic domain. The function of L1 is also dependent on trafficking through lipid rafts. Our hypothesis is that L1 is a target for ethanol neurotoxicity in vivo. Our objective is to demonstrate changes in L1 phosphorylation/dephosphorylation and lipid raft association in vivo. Methods Rat pups on postnatal day 6 are administered 4.5, 5.25 and 6 g/kg of ethanol divided into 2 doses 2 hours apart, then sacrificed. Cerebella are rapidly frozen for assay. Blood is analyzed for blood ethanol concentration. L1 tyrosine phosphorylation is determined by immunoprecipitation and dephosphorylation of tyrosine 1176 determined by immunoblot. Lipid rafts are isolated by sucrose density gradient and the distribution of L1 in lipid rafts is determined. Results Ethanol at all doses reduced the relative amount of Y1176 dephosphorylation as well as the relative amount of L1 phosphorylated on other tyrosines. The proportion of L1 present in lipid rafts is significantly increased in pups who received 6 g/kg ethanol compared to intubated controls. Conclusions L1 is a target for ethanol developmental neurotoxicity in vivo. PMID:23050935

  14. Measles Virus Entry Through the Signaling Lymphocyte Activation Molecule Governs Efficacy of Mantle Cell Lymphoma Radiovirotherapy

    PubMed Central

    Miest, Tanner S; Frenzke, Marie; Cattaneo, Roberto

    2013-01-01

    We developed here a vaccine-identical measles virus (MV) as an oncolytic agent against mantle cell lymphoma (MCL), an aggressive B-cell non-Hodgkin's lymphoma that is difficult to cure but radiosensitive. We armed the virus with the sodium-iodide symporter, which concentrates iodide within infected cells enabling noninvasive imaging and combination radiovirotherapy. Through high-resolution in vivo and ex vivo imaging, we visualized the spread of infections in primary and metastatic tumors for over 2 weeks after therapy, documenting homogeneous virus seeding and spread restricted to perfused tissue. Infection of metastases was more rapid and intense than primary tumors, achieving isotope uptake within about threefold the efficiency of the thyroid. Virotherapy combined with systemic 131I resulted in more rapid disease regression than either therapy alone. In addition to ubiquitous CD46, vaccine MV retains cell entry through its immune cell-specific receptor signaling lymphocytic activation molecule (SLAM). We asked whether both receptors could sustain effective oncolysis of MCL. Strikingly, only SLAM-dependent entry sustained efficient viral spread, tumor regression, and prolonged survival. These observations shift the focus of future clinical trials to SLAM-expressing hematologic malignancies and suggest that oncolytic vectors may depend on tissue-specific receptors for both cell entry and activation of responses assisting their replication. PMID:23913184

  15. The adhesion molecule NCAM promotes ovarian cancer progression via FGFR signalling

    PubMed Central

    Zecchini, Silvia; Bombardelli, Lorenzo; Decio, Alessandra; Bianchi, Marco; Mazzarol, Giovanni; Sanguineti, Fabio; Aletti, Giovanni; Maddaluno, Luigi; Berezin, Vladimir; Bock, Elisabeth; Casadio, Chiara; Viale, Giuseppe; Colombo, Nicoletta; Giavazzi, Raffaella; Cavallaro, Ugo

    2011-01-01

    Epithelial ovarian carcinoma (EOC) is an aggressive neoplasm, which mainly disseminates to organs of the peritoneal cavity, an event mediated by molecular mechanisms that remain elusive. Here, we investigated the expression and functional role of neural cell adhesion molecule (NCAM), a cell surface glycoprotein involved in brain development and plasticity, in EOC. NCAM is absent from normal ovarian epithelium but becomes highly expressed in a subset of human EOC, in which NCAM expression is associated with high tumour grade, suggesting a causal role in cancer aggressiveness. We demonstrate that NCAM stimulates EOC cell migration and invasion in vitro and promotes metastatic dissemination in mice. This pro-malignant function of NCAM is mediated by its interaction with fibroblast growth factor receptor (FGFR). Indeed, not only FGFR signalling is required for NCAM-induced EOC cell motility, but targeting the NCAM/FGFR interplay with a monoclonal antibody abolishes the metastatic dissemination of EOC in mice. Our results point to NCAM-mediated stimulation of FGFR as a novel mechanism underlying EOC malignancy and indicate that this interplay may represent a valuable therapeutic target. PMID:21739604

  16. Lysophosphatidylcholine and lysophosphatidylinosiol--novel promissing signaling molecules and their possible therapeutic activity.

    PubMed

    Drzazga, Anna; Sowińska, Agata; Koziołkiewicz, Maria

    2014-01-01

    For many years the role of lysophospholipids (LPLs) was associated only with structural and storage components of the cell without any informational function. Today, based on many research projects performed during the last decades, it is clear that some of the LPLs act as hormone-like signaling molecules and thus are very important inter- and intracellular lipid mediators. They can activate specific membrane receptors and/or nuclear receptors regulating many crucial physiological and pathophysiological processes. The LPLs were iden- tified as involved in a majority of cellular processes, including modulation of disease-related mechanisms observed, for instance, in case of diabetes, obesity, atherosclerosis and cancer. Among LPLs, lysophosphatidylcholine (LPC) and lysophosphatidylinositol (LPI) are becoming attractive research topics. Their recently revealed activities as novel ligands of orphan G protein-coupled receptors (i.e., GPR55 and GPR119) involved in modulation of tumor physiology and insulin secretion seem to be one of the most interesting aspects of these compounds. Moreover, the most recent scientific reports emphasize the significance of the acyl chain structure bound to the glycerol basis of LPL, as it entails different biological properties and activities of the compounds. PMID:25745761

  17. Morphofunctional and signaling molecules overlap of the pineal gland and thymus: role and significance in aging

    PubMed Central

    Paltsev, Michael A.; Polyakova, Victoria O.; Kvetnoy, Igor M.; Anderson, George; Kvetnaia, Tatiana V.; Linkova, Natalia S.; Paltseva, Ekaterina M.; Rubino, Rosa; De Cosmo, Salvatore; De Cata, Angelo; Mazzoccoli, Gianluigi

    2016-01-01

    Deficits in neuroendocrine-immune system functioning, including alterations in pineal and thymic glands, contribute to aging-associated diseases. This study looks at ageing-associated alterations in pineal and thymic gland functioning evaluating common signaling molecules present in both human and animal pinealocytes and thymocytes: endocrine cell markers (melatonin, serotonin, pCREB, AANAT, CGRP, VIP, chromogranin A); cell renovation markers (p53, AIF, Ki67), matrix metalloproteinases (MMP2, MMP9) and lymphocytes markers (CD4, CD5, CD8, CD20). Pineal melatonin is decreased, as is one of the melatonin pathway synthesis enzymes in the thymic gland. A further similarity is the increased MMPs levels evident over age in both glands. Significant differences are evident in cell renovation processes, which deteriorate more quickly in the aged thymus versus the pineal gland. Decreases in the number of pineal B-cells and thymic T-cells were also observed over aging. Collected data indicate that cellular involution of the pineal gland and thymus show many commonalities, but also significant changes in aging-associated proteins. It is proposed that such ageing-associated alterations in these two glands provide novel pharmaceutical targets for the wide array of medical conditions that are more likely to emerge over the course of ageing. PMID:26943046

  18. A Small Molecule Inhibits Virion Attachment to Heparan Sulfate- or Sialic Acid-Containing Glycans

    PubMed Central

    Colpitts, Che C.

    2014-01-01

    ABSTRACT Primary attachment to cellular glycans is a critical entry step for most human viruses. Some viruses, such as herpes simplex virus type 1 (HSV-1) and hepatitis C virus (HCV), bind to heparan sulfate, whereas others, such as influenza A virus (IAV), bind to sialic acid. Receptor mimetics that interfere with these interactions are active against viruses that bind to either heparan sulfate or to sialic acid. However, no molecule that inhibits the attachment of viruses in both groups has yet been identified. Epigallocatechin gallate (EGCG), a green tea catechin, is active against many unrelated viruses, including several that bind to heparan sulfate or to sialic acid. We sought to identify the basis for the broad-spectrum activity of EGCG. Here, we show that EGCG inhibits the infectivity of a diverse group of enveloped and nonenveloped human viruses. EGCG acts directly on the virions, without affecting the fluidity or integrity of the virion envelopes. Instead, EGCG interacts with virion surface proteins to inhibit the attachment of HSV-1, HCV, IAV, vaccinia virus, adenovirus, reovirus, and vesicular stomatitis virus (VSV) virions. We further show that EGCG competes with heparan sulfate for binding of HSV-1 and HCV virions and with sialic acid for binding of IAV virions. Therefore, EGCG inhibits unrelated viruses by a common mechanism. Most importantly, we have identified EGCG as the first broad-spectrum attachment inhibitor. Our results open the possibility for the development of small molecule broad-spectrum antivirals targeting virion attachment. IMPORTANCE This study shows that it is possible to develop a small molecule antiviral or microbicide active against the two largest groups of human viruses: those that bind to glycosaminoglycans and those that bind to sialoglycans. This group includes the vast majority of human viruses, including herpes simplex viruses, cytomegalovirus, influenza virus, poxvirus, hepatitis C virus, HIV, and many others. PMID

  19. EMBO Retinoids 2011: mechanisms, biology and pathology of signaling by retinoic acid and retinoic acid receptors

    PubMed Central

    McKenna, Neil J.

    2012-01-01

    Retinoic acid (RA) is one of the principal active metabolites of vitamin A (retinol) which mediates a spectrum of critical physiological and developmental processes. Transcriptional regulation by RA is mediated primarily by members of the retinoic acid receptor (RAR) subfamily of the nuclear receptor (NR) superfamily of transcription factors. NRs bind specific genomic DNA sequence motifs and engage coregulators and components of the basal transcription machinery to effect transcriptional regulation at target gene promoters. Disruption of signaling by retinoic acid is thought to underlie the etiology of a number of inflammatory and neoplastic diseases including breast cancer and haematological malignancies. A meeting of international researchers in retinoid signaling was convened in Strasbourg in September 2011 under the auspices of the European Molecular Biology Organization (EMBO). Retinoids 2011 encompassed myriad mechanistic, biological and pathological aspects of these hormones and their cognate receptors, as well as setting these advances in the context of wider current questions on signaling by members of the NR superfamily. PMID:22438793

  20. Defective phosphatidic acid-phospholipase C signaling in diabetic cardiomyopathy.

    PubMed

    Tappia, Paramjit S; Maddaford, Thane G; Hurtado, Cecilia; Dibrov, Elena; Austria, J Alejandro; Sahi, Nidhi; Panagia, Vincenzo; Pierce, Grant N

    2004-03-26

    The effects of exogenous phosphatidic acid (PA) on Ca2+ transients and contractile activity were studied in cardiomyocytes isolated from chronic streptozotocin-induced diabetic rats. In control cells, 25 microM PA induced a significant increase in active cell shortening and Ca2+ transients. PA increased IP3 generation in the control cardiomyocytes and its inotropic effects were blocked by a phospholipase C inhibitor. In cardiomyocytes from diabetic rats, PA induced a 25% decrease in active cell shortening and no significant effect on Ca2+ transients. Basal and PA-induced IP3 generation in diabetic rat cardiomyocytes was 3-fold lower as compared to control cells. Sarcolemmal membrane PLC activity was impaired. Insulin treatment of the diabetic animals resulted in a partial recovery of PA responses. Our results, therefore, identify an important defect in the PA-PLC signaling pathway in diabetic rat cardiomyocytes, which may have significant implications for heart dysfunction during diabetes. PMID:15003542

  1. Signalling diacylglycerol pyrophosphate, a new phosphatidic acid metabolite.

    PubMed

    van Schooten, Bas; Testerink, Christa; Munnik, Teun

    2006-02-01

    Diacylglycerol pyrophosphate (DGPP) is a novel phospholipid that has been found in plants and yeast but not in higher animals. It is produced through phosphorylation of phosphatidic acid (PA) by the novel enzyme PA kinase (PAK). In plants, DGPP is virtually absent in non-stimulated cells but its concentration increases within minutes in response to various stimuli, including osmotic stress and pathogen attack, implying a role in stress signalling. DGPP is broken down by the enzyme DGPP phosphatase (DPP). DPP-encoding genes have been cloned from Arabidopsis thaliana and Saccharomyces cerevisiae (DPP1). In S. cerevisiae, the expression of DPP1 is regulated coordinately with the majority of genes encoding enzymes involved in phospholipid biosynthesis. PMID:16469533

  2. Lysophosphatidic acid regulates adhesion molecules and enhances migration of human oral keratinocytes.

    PubMed

    Thorlakson, Hong H; Schreurs, Olav; Schenck, Karl; Blix, Inger J S

    2016-04-01

    Oral keratinocytes are connected via cell-to-cell adhesions to protect underlying tissues from physical and bacterial damage. Lysophosphatidic acids (LPAs) are a family of phospholipid mediators that have the ability to regulate gene expression, cytoskeletal rearrangement, and cytokine/chemokine secretion, which mediate proliferation, migration, and differentiation. Several forms of LPA are found in saliva and gingival crevicular fluid, but it is unknown how they affect human oral keratinocytes (HOK). The aim of the present study was therefore to examine how different LPA forms affect the expression of adhesion molecules and the migration and proliferation of HOK. Keratinocytes were isolated from gingival biopsies obtained from healthy donors and challenged with different forms of LPA. Quantitative real-time RT-PCR, immunocytochemistry, and flow cytometry were used to analyze the expression of adhesion molecules. Migration and proliferation assays were performed. Lysophosphatidic acids strongly promoted expression of E-cadherin and occludin mRNAs and translocation of E-cadherin protein from the cytoplasm to the membrane. Occludin and claudin-1 proteins were up-regulated by LPA. Migration of HOK in culture was increased, but proliferation was reduced, by the addition of LPA. This indicates that LPA can have a role in the regulation of the oral epithelial barrier by increasing the expression of adhesion molecules of HOK, by promotion of migration and by inhibition of proliferation. PMID:26913569

  3. Abscisic-acid-induced cellular apoptosis and differentiation in glioma via the retinoid acid signaling pathway.

    PubMed

    Zhou, Nan; Yao, Yu; Ye, Hongxing; Zhu, Wei; Chen, Liang; Mao, Ying

    2016-04-15

    Retinoid acid (RA) plays critical roles in regulating differentiation and apoptosis in a variety of cancer cells. Abscisic acid (ABA) and RA are direct derivatives of carotenoids and share structural similarities. Here we proposed that ABA may also play a role in cellular differentiation and apoptosis by sharing a similar signaling pathway with RA that may be involved in glioma pathogenesis. We reported for the first time that the ABA levels were twofold higher in low-grade gliomas compared with high-grade gliomas. In glioma tissues, there was a positive correlation between the ABA levels and the transcription of cellular retinoic acid-binding protein 2 (CRABP2) and a negative correlation between the ABA levels and transcription of fatty acid-binding protein 5 (FABP5). ABA treatment induced a significant increase in the expression of CRABP2 and a decrease in the expression of peroxisome proliferator-activated receptor (PPAR) in glioblastoma cells. Remarkably, both cellular apoptosis and differentiation were increased in the glioblastoma cells after ABA treatment. ABA-induced cellular apoptosis and differentiation were significantly reduced by selectively silencing RAR-α, while RAR-α overexpression exaggerated the ABA-induced effects. These results suggest that ABA may play a role in the pathogenesis of glioma by promoting cellular apoptosis and differentiation through the RA signaling pathway. PMID:26594836

  4. Basic amino-acid side chains regulate transmembrane integrin signalling.

    PubMed

    Kim, Chungho; Schmidt, Thomas; Cho, Eun-Gyung; Ye, Feng; Ulmer, Tobias S; Ginsberg, Mark H

    2012-01-12

    Side chains of Lys/Arg near transmembrane domain (TMD) membrane-water interfaces can 'snorkel', placing their positive charge near negatively charged phospholipid head groups; however, snorkelling's functional effects are obscure. Integrin β TMDs have such conserved basic amino acids. Here we use NMR spectroscopy to show that integrin β(3)(Lys 716) helps determine β(3) TMD topography. The α(ΙΙb)β(3) TMD structure indicates that precise β(3) TMD crossing angles enable the assembly of outer and inner membrane 'clasps' that hold the αβ TMD together to limit transmembrane signalling. Mutation of β(3)(Lys 716) caused dissociation of α(ΙΙb)β(3) TMDs and integrin activation. To confirm that altered topography of β(3)(Lys 716) mutants activated α(ΙΙb)β(3), we used directed evolution of β(3)(K716A) to identify substitutions restoring default state. Introduction of Pro(711) at the midpoint of β(3) TMD (A711P) increased α(ΙΙb)β(3) TMD association and inactivated integrin α(ΙΙb)β(3)(A711P,K716A). β(3)(Pro 711) introduced a TMD kink of 30 ± 1° precisely at the border of the outer and inner membrane clasps, thereby decoupling the tilt between these segments. Thus, widely occurring snorkelling residues in TMDs can help maintain TMD topography and membrane-embedding, thereby regulating transmembrane signalling. PMID:22178926

  5. Abscisic acid perception and signaling: structural mechanisms and applications

    PubMed Central

    Ng, Ley Moy; Melcher, Karsten; Teh, Bin Tean; Xu, H Eric

    2014-01-01

    Adverse environmental conditions are a threat to agricultural yield and therefore exert a global effect on livelihood, health and the economy. Abscisic acid (ABA) is a vital plant hormone that regulates abiotic stress tolerance, thereby allowing plants to cope with environmental stresses. Previously, attempts to develop a complete understanding of the mechanisms underlying ABA signaling have been hindered by difficulties in the identification of bona fide ABA receptors. The discovery of the PYR/PYL/RCAR family of ABA receptors therefore represented a major milestone in the effort to overcome these roadblocks; since then, many structural and functional studies have provided detailed insights into processes ranging from ABA perception to the activation of ABA-responsive gene transcription. This understanding of the mechanisms of ABA perception and signaling has served as the basis for recent, preliminary developments in the genetic engineering of stress-resistant crops as well as in the design of new synthetic ABA agonists, which hold great promise for the agricultural enhancement of stress tolerance. PMID:24786231

  6. Si Shen Wan Inhibits mRNA Expression of Apoptosis-Related Molecules in p38 MAPK Signal Pathway in Mice with Colitis

    PubMed Central

    Zhao, Hai-Mei; Huang, Xiao-Ying; Zhou, Feng; Tong, Wen-Ting; Wan, Pan-Ting; Huang, Min-Fang; Ye, Qing; Liu, Duan-Yong

    2013-01-01

    Si Shen Wan (SSW) is used to effectively treat ulcerative colitis (UC) as a formula of traditional Chinese medicine. To explore the mechanism of SSW-inhibited apoptosis of colonic epithelial cell, the study observed mRNA expression of apoptosis-related molecules in p38 MAPK signal pathway in colonic mucosa in colitis mice treated with SSW. Experimental colitis was induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) in mice; meanwhile, the mice were administrated daily either SSW (5 g/kg) or p38 MAPK inhibitor (2 mg/kg) or vehicle (physiological saline) for 10 days. While microscopical evaluation was observed, apoptosis rate of colonic epithelial cell and mRNA expression of apoptosis-related molecules were tested. Compared with colitis mice without treatment, SSW alleviated colonic mucosal injuries and decreased apoptosis rate of colonic epithelial cell, while the mRNA expressions of p38 MAPK, p53, caspase-3, c-jun, c-fos, Bax, and TNF-α were decreased in the colonic mucosa in colitis mice treated with SSW, and Bcl-2 mRNA and the ratio of Bcl-2/Bax were increased. The present study demonstrated that SSW inhibited mRNA expression of apoptosis-related molecules in p38 MAPK signal pathway to downregulate colonic epithelial cells apoptosis in colonic mucosa in mice with colitis. PMID:24223057

  7. Ursodeoxycholic Acid (UDCA) Exerts Anti-Atherogenic Effects by Inhibiting RAGE Signaling in Diabetic Atherosclerosis

    PubMed Central

    Chung, Jihwa; An, Shung Hyun; Kang, Sang Won; Kwon, Kihwan

    2016-01-01

    A naturally occurring bile acid, ursodeoxycholic acid (UDCA), is known to alleviate endoplasmic reticulum (ER) stress at the cellular level. However, the detailed action mechanisms of UDCA in atherosclerosis are not fully understood. In this study, we demonstrated whether UDCA exerts anti-atherogenic activity in diabetic atherosclerosis by targeting ER stress and “receptor for advanced glycation endproduct” (RAGE) signaling. UDCA markedly reduced ER stress, RAGE expression, and pro-inflammatory responses [including NF-κB activation and reactive oxygen species (ROS) production] induced in endothelial cells (ECs) by high glucose (HG). In particular, UDCA inhibited HG-induced ROS production by increasing the Nrf2 level. In macrophages, UDCA also blocked HG-induced RAGE and pro-inflammatory cytokine expression and inhibited foam cell formation via upregulation of the ATP-binding cassette (ABC) transporters, ABCA1 and ABCG1. In the diabetic mouse model, UDCA inhibited atheromatous plaque formation by decreasing ER stress, and the levels of RAGE and adhesion molecules. In conclusion, UDCA exerts an anti-atherogenic activity in diabetic atherosclerosis by targeting both ER stress and RAGE signaling. Our work implicates UDCA as a potential therapeutic agent for prevention or treatment of diabetic atherosclerosis. PMID:26807573

  8. Modeling the binding of fulvic acid by goethite: the speciation of adsorbed FA molecules

    NASA Astrophysics Data System (ADS)

    Filius, Jeroen D.; Meeussen, Johannes C. L.; Lumsdon, David G.; Hiemstra, Tjisse; van Riemsdijk, Willem H.

    2003-04-01

    Under natural conditions, the adsorption of ions at the solid-water interface may be strongly influenced by the adsorption of organic matter. In this paper, we describe the adsorption of fulvic acid (FA) by metal(hydr)oxide surfaces with a heterogeneous surface complexation model, the ligand and charge distribution (LCD) model. The model is a self-consistent combination of the nonideal competitive adsorption (NICA) equation and the CD-MUSIC model. The LCD model can describe simultaneously the concentration, pH, and salt dependency of the adsorption with a minimum of only three adjustable parameters. Furthermore, the model predicts the coadsorption of protons accurately for an extended range of conditions. Surface speciation calculations show that almost all hydroxyl groups of the adsorbed FA molecules are involved in outer sphere complexation reactions. The carboxylic groups of the adsorbed FA molecule form inner and outer sphere complexes. Furthermore, part of the carboxylate groups remain noncoordinated and deprotonated.

  9. Controlled synthesis and inclusion ability of a hyaluronic acid derivative bearing beta-cyclodextrin molecules.

    PubMed

    Charlot, Aurélia; Heyraud, Alain; Guenot, Pierre; Rinaudo, Marguerite; Auzély-Velty, Rachel

    2006-03-01

    A new synthetic route to beta-cyclodextrin-linked hyaluronic acid (HA-CD) was developed. This was based on the preparation of a HA derivative selectively modified with adipic dihydrazide (HA-ADH) and a beta-cyclodextrin derivative possessing an aldehyde function on the primary face, followed by their coupling by a reductive amination-type reaction. The CD-polysaccharide was fully characterized in terms of chemical integrity and purity by high-resolution NMR spectroscopy. The complexation ability of the grafted CD was further demonstrated by isothermal titration calorimetry using sodium adamantane acetate (ADAc) and Ibuprofen as model guest molecules. The thermodynamic parameters for the complexation of these negatively charged guest molecules by the beta-CD grafted on negatively charged HA were shown to be largely influenced by the ionic strength of the aqueous medium. PMID:16529430

  10. An acidic microenvironment sets the humoral pattern recognition molecule PTX3 in a tissue repair mode.

    PubMed

    Doni, Andrea; Musso, Tiziana; Morone, Diego; Bastone, Antonio; Zambelli, Vanessa; Sironi, Marina; Castagnoli, Carlotta; Cambieri, Irene; Stravalaci, Matteo; Pasqualini, Fabio; Laface, Ilaria; Valentino, Sonia; Tartari, Silvia; Ponzetta, Andrea; Maina, Virginia; Barbieri, Silvia S; Tremoli, Elena; Catapano, Alberico L; Norata, Giuseppe D; Bottazzi, Barbara; Garlanda, Cecilia; Mantovani, Alberto

    2015-06-01

    Pentraxin 3 (PTX3) is a fluid-phase pattern recognition molecule and a key component of the humoral arm of innate immunity. In four different models of tissue damage in mice, PTX3 deficiency was associated with increased fibrin deposition and persistence, and thicker clots, followed by increased collagen deposition, when compared with controls. Ptx3-deficient macrophages showed defective pericellular fibrinolysis in vitro. PTX3-bound fibrinogen/fibrin and plasminogen at acidic pH and increased plasmin-mediated fibrinolysis. The second exon-encoded N-terminal domain of PTX3 recapitulated the activity of the intact molecule. Thus, a prototypic component of humoral innate immunity, PTX3, plays a nonredundant role in the orchestration of tissue repair and remodeling. Tissue acidification resulting from metabolic adaptation during tissue repair sets PTX3 in a tissue remodeling and repair mode, suggesting that matrix and microbial recognition are common, ancestral features of the humoral arm of innate immunity. PMID:25964372

  11. An acidic microenvironment sets the humoral pattern recognition molecule PTX3 in a tissue repair mode

    PubMed Central

    Doni, Andrea; Musso, Tiziana; Morone, Diego; Bastone, Antonio; Zambelli, Vanessa; Sironi, Marina; Castagnoli, Carlotta; Cambieri, Irene; Stravalaci, Matteo; Pasqualini, Fabio; Laface, Ilaria; Valentino, Sonia; Tartari, Silvia; Ponzetta, Andrea; Maina, Virginia; Barbieri, Silvia S.; Tremoli, Elena; Catapano, Alberico L.; Norata, Giuseppe D.; Bottazzi, Barbara; Garlanda, Cecilia

    2015-01-01

    Pentraxin 3 (PTX3) is a fluid-phase pattern recognition molecule and a key component of the humoral arm of innate immunity. In four different models of tissue damage in mice, PTX3 deficiency was associated with increased fibrin deposition and persistence, and thicker clots, followed by increased collagen deposition, when compared with controls. Ptx3-deficient macrophages showed defective pericellular fibrinolysis in vitro. PTX3-bound fibrinogen/fibrin and plasminogen at acidic pH and increased plasmin-mediated fibrinolysis. The second exon-encoded N-terminal domain of PTX3 recapitulated the activity of the intact molecule. Thus, a prototypic component of humoral innate immunity, PTX3, plays a nonredundant role in the orchestration of tissue repair and remodeling. Tissue acidification resulting from metabolic adaptation during tissue repair sets PTX3 in a tissue remodeling and repair mode, suggesting that matrix and microbial recognition are common, ancestral features of the humoral arm of innate immunity. PMID:25964372

  12. A systematic method for studying the spatial distribution of water molecules around nucleic acid bases.

    PubMed Central

    Schneider, B; Cohen, D M; Schleifer, L; Srinivasan, A R; Olson, W K; Berman, H M

    1993-01-01

    A new method to analyze the distribution of water molecules around the bases in DNA is presented. This method relies on the notion of a "hydrated building block," which represents the joint observed hydration around all bases of a particular type, in structures of a particular conformation type. The hydrated building blocks were constructed using atomic coordinates from 40 structures contained in the Nucleic Acid Database. Pseudoelectron densities were calculated for water molecules in each hydrated building block using standard crystallographic procedures. The electron densities were fitted to obtain "average building blocks," which represent bases with waters only at average or probable positions. Both types of building blocks were used to construct models of hydrated DNA oligomers. The essential features of the solvent structure around d(CGCGAATTCGCG)2 in the B form and d(CGCGCG)2 in the Z form were reproduced. Images FIGURE 4 FIGURE 5 PMID:8312469

  13. Molecular understanding of atmospheric particle formation from sulfuric acid and large oxidized organic molecules

    PubMed Central

    Schobesberger, Siegfried; Junninen, Heikki; Bianchi, Federico; Lönn, Gustaf; Ehn, Mikael; Lehtipalo, Katrianne; Dommen, Josef; Ehrhart, Sebastian; Ortega, Ismael K.; Franchin, Alessandro; Nieminen, Tuomo; Riccobono, Francesco; Hutterli, Manuel; Duplissy, Jonathan; Almeida, João; Amorim, Antonio; Breitenlechner, Martin; Downard, Andrew J.; Dunne, Eimear M.; Flagan, Richard C.; Kajos, Maija; Keskinen, Helmi; Kirkby, Jasper; Kupc, Agnieszka; Kürten, Andreas; Kurtén, Theo; Laaksonen, Ari; Mathot, Serge; Onnela, Antti; Praplan, Arnaud P.; Rondo, Linda; Santos, Filipe D.; Schallhart, Simon; Schnitzhofer, Ralf; Sipilä, Mikko; Tomé, António; Tsagkogeorgas, Georgios; Vehkamäki, Hanna; Wimmer, Daniela; Baltensperger, Urs; Carslaw, Kenneth S.; Curtius, Joachim; Hansel, Armin; Petäjä, Tuukka; Kulmala, Markku; Donahue, Neil M.; Worsnop, Douglas R.

    2013-01-01

    Atmospheric aerosols formed by nucleation of vapors affect radiative forcing and therefore climate. However, the underlying mechanisms of nucleation remain unclear, particularly the involvement of organic compounds. Here, we present high-resolution mass spectra of ion clusters observed during new particle formation experiments performed at the Cosmics Leaving Outdoor Droplets chamber at the European Organization for Nuclear Research. The experiments involved sulfuric acid vapor and different stabilizing species, including ammonia and dimethylamine, as well as oxidation products of pinanediol, a surrogate for organic vapors formed from monoterpenes. A striking resemblance is revealed between the mass spectra from the chamber experiments with oxidized organics and ambient data obtained during new particle formation events at the Hyytiälä boreal forest research station. We observe that large oxidized organic compounds, arising from the oxidation of monoterpenes, cluster directly with single sulfuric acid molecules and then form growing clusters of one to three sulfuric acid molecules plus one to four oxidized organics. Most of these organic compounds retain 10 carbon atoms, and some of them are remarkably highly oxidized (oxygen-to-carbon ratios up to 1.2). The average degree of oxygenation of the organic compounds decreases while the clusters are growing. Our measurements therefore connect oxidized organics directly, and in detail, with the very first steps of new particle formation and their growth between 1 and 2 nm in a controlled environment. Thus, they confirm that oxidized organics are involved in both the formation and growth of particles under ambient conditions. PMID:24101502

  14. Molecular understanding of atmospheric particle formation from sulfuric acid and large oxidized organic molecules.

    PubMed

    Schobesberger, Siegfried; Junninen, Heikki; Bianchi, Federico; Lönn, Gustaf; Ehn, Mikael; Lehtipalo, Katrianne; Dommen, Josef; Ehrhart, Sebastian; Ortega, Ismael K; Franchin, Alessandro; Nieminen, Tuomo; Riccobono, Francesco; Hutterli, Manuel; Duplissy, Jonathan; Almeida, João; Amorim, Antonio; Breitenlechner, Martin; Downard, Andrew J; Dunne, Eimear M; Flagan, Richard C; Kajos, Maija; Keskinen, Helmi; Kirkby, Jasper; Kupc, Agnieszka; Kürten, Andreas; Kurtén, Theo; Laaksonen, Ari; Mathot, Serge; Onnela, Antti; Praplan, Arnaud P; Rondo, Linda; Santos, Filipe D; Schallhart, Simon; Schnitzhofer, Ralf; Sipilä, Mikko; Tomé, António; Tsagkogeorgas, Georgios; Vehkamäki, Hanna; Wimmer, Daniela; Baltensperger, Urs; Carslaw, Kenneth S; Curtius, Joachim; Hansel, Armin; Petäjä, Tuukka; Kulmala, Markku; Donahue, Neil M; Worsnop, Douglas R

    2013-10-22

    Atmospheric aerosols formed by nucleation of vapors affect radiative forcing and therefore climate. However, the underlying mechanisms of nucleation remain unclear, particularly the involvement of organic compounds. Here, we present high-resolution mass spectra of ion clusters observed during new particle formation experiments performed at the Cosmics Leaving Outdoor Droplets chamber at the European Organization for Nuclear Research. The experiments involved sulfuric acid vapor and different stabilizing species, including ammonia and dimethylamine, as well as oxidation products of pinanediol, a surrogate for organic vapors formed from monoterpenes. A striking resemblance is revealed between the mass spectra from the chamber experiments with oxidized organics and ambient data obtained during new particle formation events at the Hyytiälä boreal forest research station. We observe that large oxidized organic compounds, arising from the oxidation of monoterpenes, cluster directly with single sulfuric acid molecules and then form growing clusters of one to three sulfuric acid molecules plus one to four oxidized organics. Most of these organic compounds retain 10 carbon atoms, and some of them are remarkably highly oxidized (oxygen-to-carbon ratios up to 1.2). The average degree of oxygenation of the organic compounds decreases while the clusters are growing. Our measurements therefore connect oxidized organics directly, and in detail, with the very first steps of new particle formation and their growth between 1 and 2 nm in a controlled environment. Thus, they confirm that oxidized organics are involved in both the formation and growth of particles under ambient conditions. PMID:24101502

  15. Ab initio investigation of the adsorption of zoledronic acid molecule on hydroxyapatite (001) surface: an atomistic insight of bone protection

    NASA Astrophysics Data System (ADS)

    Ri, Mun-Hyok; Yu, Chol-Jun; Jang, Yong-Man; Kim, Song-Un

    2016-03-01

    We report a computational study of the adsorption of zoledronic acid molecule on hydroxyapatite (001) surface within ab initio density functional theory. The systematic study has been performed, from hydroxyapatite bulk and surface, and zoledronic acid molecule to the adsorption of the molecule on the surface. The optimized bond lengths and bond angles were obtained and analyzed, giving an evidence of structural similarity between subjects under study. The formation energies of hydroxyapatite (001) surfaces with two kinds of terminations were computed as about 1.2 and 1.5 J/m^2 with detailed atomistic structural information. We determined the adsorption energies of zoledronic acid molecule on the surfaces, which are -260 kJ/mol at 0.25 ML and -400 kJ/mol at 0.5 ML. An atomistic insight of strong binding affinity of zoledronic acid to the hydroxyapatite surface was given and discussed.

  16. Once and again: retinoic acid signaling in the developing and regenerating olfactory pathway.

    PubMed

    Rawson, N E; LaMantia, A-S

    2006-06-01

    Retinoic acid (RA), a member of the steroid/thyroid superfamily of signaling molecules, is an essential regulator of morphogenesis, differentiation, and regeneration in the mammalian olfactory pathway. RA-mediated teratogenesis dramatically alters olfactory pathway development, presumably by disrupting retinoid-mediated inductive signaling that influences initial olfactory epithelium (OE) and bulb (OB) morphogenesis. Subsequently, RA modulates the genesis, growth, or stability of subsets of OE cells and OB interneurons. RA receptors, cofactors, and synthetic enzymes are expressed in the OE, OB, and anterior subventricular zone (SVZ), the site of neural precursors that generate new OB interneurons throughout adulthood. Their expression apparently accommodates RA signaling in OE cells, OB interneurons, and slowly dividing SVZ neural precursors. Deficiency of vitamin A, the dietary metabolic RA precursor, leads to cytological changes in the OE, as well as olfactory sensory deficits. Vitamin A therapy in animals with olfactory system damage can accelerate functional recovery. RA-related pathology as well as its potential therapeutic activity may reflect endogenous retinoid regulation of neuronal differentiation, stability, or regeneration in the olfactory pathway from embryogenesis through adulthood. These influences may be in register with retinoid effects on immune responses, metabolism, and modulation of food intake. PMID:16688760

  17. Elastic Properties of Nucleic Acids by Single-Molecule Force Spectroscopy.

    PubMed

    Camunas-Soler, Joan; Ribezzi-Crivellari, Marco; Ritort, Felix

    2016-07-01

    We review the current knowledge on the use of single-molecule force spectroscopy techniques to extrapolate the elastic properties of nucleic acids. We emphasize the lesser-known elastic properties of single-stranded DNA. We discuss the importance of accurately determining the elastic response in pulling experiments, and we review the simplest models used to rationalize the experimental data as well as the experimental approaches used to pull single-stranded DNA. Applications used to investigate DNA conformational transitions and secondary structure formation are also highlighted. Finally, we provide an overview of the effects of salt and temperature and briefly discuss the effects of contour length and sequence dependence. PMID:27145878

  18. Mycosporine-like amino acids are multifunctional molecules in sea hares and their marine community

    PubMed Central

    Kicklighter, Cynthia E.; Kamio, Michiya; Nguyen, Linh; Germann, Markus W.; Derby, Charles D.

    2011-01-01

    Molecules of keystone significance are relatively rare, yet mediate a variety of interactions between organisms. They influence the distribution and abundance of species, the transfer of energy across multiple trophic levels, and thus they play significant roles in structuring ecosystems. Despite their potential importance in facilitating our understanding of ecological systems, only three molecules thus far have been proposed as molecules of keystone significance: saxitoxin and dimethyl sulfide in marine communities and tetrodotoxin in riparian communities. In the course of studying the neuroecology of chemical defenses, we identified three mycosporine-like amino acids (MAAs)—N-ethanol palythine (= asterina-330), N-isopropanol palythine (= aplysiapalythine A), and N-ethyl palythine (= aplysiapalythine B)—as intraspecific alarm cues for sea hares (Aplysia californica). These alarm cues are released in the ink secretion of sea hares and cause avoidance behaviors in neighboring conspecifics. Further, we show that these three bioactive MAAs, two [aplysiapalythine A (APA) and -B (APB)] being previously unknown molecules, are present in the algal diet of sea hares and are concentrated in their defensive secretion as well as in their skin. MAAs are known to be produced by algae, fungi, and cyanobacteria and are acquired by many aquatic animals through trophic interactions. MAAs are widely used as sunscreens, among other uses, but sea hares modify their function to serve a previously undocumented role, as intraspecific chemical cues. Our findings highlight the multifunctionality of MAAs and their role in ecological connectivity, suggesting that they may function as molecules of keystone significance in marine ecosystems. PMID:21709250

  19. A Small Molecule Screen Exposes mTOR Signaling Pathway Involvement in Radiation-Induced Apoptosis.

    PubMed

    Sharlow, Elizabeth R; Leimgruber, Stephanie; Lira, Ana; McConnell, Michael J; Norambuena, Andrés; Bloom, George S; Epperly, Michael W; Greenberger, Joel S; Lazo, John S

    2016-05-20

    Individuals are at risk of exposure to acute ionizing radiation (IR) from a nuclear accident or terrorism, but we lack effective therapies to mitigate the lethal IR effects. In the current study, we exploited an optimized, cell-based, high throughput screening assay to interrogate a small molecule library comprising 3437 known pharmacologically active compounds for mitigation against IR-induced apoptosis. Thirty-three library compounds significantly reduced apoptosis when administered 1 h after 4 Gy IR. Two- or three-dimensional computational structural analyses of the compounds indicated only one or two chemical clusters with most of the compounds being unique structures. The mechanistic target of rapamycin complex 1 (mTORC1) inhibitor, rapamycin, was the most potent compound, and it mitigated apoptosis by 50% at 200 ± 50 pM. Other mTOR inhibitors, namely everolimus, AZD8055, and torin 1, also suppressed apoptosis, providing additional pharmacological evidence for mTOR pathway involvement in regulating cell death after IR. Everolimus and torin 1 treatment after IR decreased the S phase population and enforced both G1 and G2 phase arrest. This prorogation of cell cycle progression was accompanied by decreased IR-induced DNA damage measured by γH2AX phosphorylation at Ser139. RNA interference-mediated knockdown of the respective mTORC1 and mTORC2 subunits, Raptor or Rictor, also mitigated IR-induced apoptosis. Collectively, this study suggests a central role for the mTOR signaling in the cytotoxic response to IR and offers a useful platform to probe for additional agents. PMID:26938669

  20. ‘Chromosomal Rainbows’ Detect Oncogenic Rearrangements of Signaling Molecules in Thyroid Tumors

    PubMed Central

    O’Brien, Benjamin; Jossart, Gregg H.; Ito, Yuko; Greulich-Bode, Karin M.; Weier, Jingly F.; Munne, Santiago; Clark, Orlo H.; Weier, Heinz-Ulrich G.

    2011-01-01

    Altered signal transduction can be considered a hallmark of many solid tumors. In thyroid cancers the receptor tyrosine kinase (rtk) genes NTRK1 (Online Mendelian Inheritance in Man = OMIM *191315, also known as ‘TRKA’), RET (‘Rearranged during Transfection protooncogene’, OMIM *164761) and MET (OMIM *164860) have been reported as activated, rearranged or overexpressed. In many cases, a combination of cytogenetic and molecular techniques allows elucidation of cellular changes that initiate tumor development and progression. While the mechanisms leading to overexpression of the rtk MET gene remain largely unknown, a variety of chromosomal rearrangements of the RET or NTKR1 gene could be demonstrated in thyroid cancer. Abnormal expressions in these tumors seem to follow a similar pattern: the rearrangement translocates the 3′- end of the rtk gene including the entire catalytic domain to an expressed gene leading to a chimeric RNA and protein with kinase activity. Our research was prompted by an increasing number of reports describing translocations involving ret and previously unknown translocation partners. We developed a high resolution technique based on fluorescence in situ hybridization (FISH) to allow rapid screening for cytogenetic rearrangements which complements conventional chromosome banding analysis. Our technique applies simultaneous hybridization of numerous probes labeled with different reporter molecules which are distributed along the target chromosome allowing the detection of cytogenetic changes at near megabasepair (Mbp) resolution. Here, we report our results using a probe set specific for human chromosome 10, which is altered in a significant portion of human thyroid cancers (TC’s). While rendering accurate information about the cytogenetic location of rearranged elements, our multi-locus, multi-color analysis was developed primarily to overcome limitations of whole chromosome painting (WCP) and chromosome banding techniques for fine

  1. Chromosomal Rainbows detect Oncogenic Rearrangements of Signaling Molecules in Thyroid Tumors

    SciTech Connect

    O'Brien, Benjamin; Jossart, Gregg H.; Ito, Yuko; Greulich-Bode, Karin M.; Weier, Jingly F.; Munne, Santiago; Clark, Orlo H.; Weier, Heinz-Ulrich G.

    2010-08-19

    Altered signal transduction can be considered a hallmark of many solid tumors. In thyroid cancers the receptor tyrosine kinase (rtk) genes NTRK1 (Online Mendelian Inheritance in Man = OMIM *191315, also known as 'TRKA'), RET ('Rearranged during Transfection protooncogene', OMIM *164761) and MET (OMIM *164860) have been reported as activated, rearranged or overexpressed. In many cases, a combination of cytogenetic and molecular techniques allows elucidation of cellular changes that initiate tumor development and progression. While the mechanisms leading to overexpression of the rtk MET gene remain largely unknown, a variety of chromosomal rearrangements of the RET or NTKR1 gene could be demonstrated in thyroid cancer. Abnormal expressions in these tumors seem to follow a similar pattern: the rearrangement translocates the 3'-end of the rtk gene including the entire catalytic domain to an expressed gene leading to a chimeric RNA and protein with kinase activity. Our research was prompted by an increasing number of reports describing translocations involving ret and previously unknown translocation partners. We developed a high resolution technique based on fluorescence in situ hybridization (FISH) to allow rapid screening for cytogenetic rearrangements which complements conventional chromosome banding analysis. Our technique applies simultaneous hybridization of numerous probes labeled with different reporter molecules which are distributed along the target chromosome allowing the detection of cytogenetic changes at near megabase-pair (Mbp) resolution. Here, we report our results using a probe set specific for human chromosome 10, which is altered in a significant portion of human thyroid cancers (TC's). While rendering accurate information about the cytogenetic location of rearranged elements, our multi-locus, multi-color analysis was developed primarily to overcome limitations of whole chromosome painting (WCP) and chromosome banding techniques for fine mapping of

  2. 'Chromosomal Rainbows' Detect Oncogenic Rearrangements of Signaling Molecules in Thyroid Tumors.

    PubMed

    O'Brien, Benjamin; Jossart, Gregg H; Ito, Yuko; Greulich-Bode, Karin M; Weier, Jingly F; Munne, Santiago; Clark, Orlo H; Weier, Heinz-Ulrich G

    2010-01-01

    Altered signal transduction can be considered a hallmark of many solid tumors. In thyroid cancers the receptor tyrosine kinase (rtk) genes NTRK1 (Online Mendelian Inheritance in Man = OMIM *191315, also known as 'TRKA'), RET ('Rearranged during Transfection protooncogene', OMIM *164761) and MET (OMIM *164860) have been reported as activated, rearranged or overexpressed. In many cases, a combination of cytogenetic and molecular techniques allows elucidation of cellular changes that initiate tumor development and progression. While the mechanisms leading to overexpression of the rtk MET gene remain largely unknown, a variety of chromosomal rearrangements of the RET or NTKR1 gene could be demonstrated in thyroid cancer. Abnormal expressions in these tumors seem to follow a similar pattern: the rearrangement translocates the 3'- end of the rtk gene including the entire catalytic domain to an expressed gene leading to a chimeric RNA and protein with kinase activity. Our research was prompted by an increasing number of reports describing translocations involving ret and previously unknown translocation partners.We developed a high resolution technique based on fluorescence in situ hybridization (FISH) to allow rapid screening for cytogenetic rearrangements which complements conventional chromosome banding analysis. Our technique applies simultaneous hybridization of numerous probes labeled with different reporter molecules which are distributed along the target chromosome allowing the detection of cytogenetic changes at near megabasepair (Mbp) resolution. Here, we report our results using a probe set specific for human chromosome 10, which is altered in a significant portion of human thyroid cancers (TC's). While rendering accurate information about the cytogenetic location of rearranged elements, our multi-locus, multi-color analysis was developed primarily to overcome limitations of whole chromosome painting (WCP) and chromosome banding techniques for fine mapping of

  3. Evolution of HLA class II molecules: Allelic and amino acid site variability across populations.

    PubMed Central

    Salamon, H; Klitz, W; Easteal, S; Gao, X; Erlich, H A; Fernandez-Viña, M; Trachtenberg, E A; McWeeney, S K; Nelson, M P; Thomson, G

    1999-01-01

    Analysis of the highly polymorphic beta1 domains of the HLA class II molecules encoded by the DRB1, DQB1, and DPB1 loci reveals contrasting levels of diversity at the allele and amino acid site levels. Statistics of allele frequency distributions, based on Watterson's homozygosity statistic F, reveal distinct evolutionary patterns for these loci in ethnically diverse samples (26 populations for DQB1 and DRB1 and 14 for DPB1). When examined over all populations, the DQB1 locus allelic variation exhibits striking balanced polymorphism (P < 10(-4)), DRB1 shows some evidence of balancing selection (P < 0.06), and while there is overall very little evidence for selection of DPB1 allele frequencies, there is a trend in the direction of balancing selection (P < 0.08). In contrast, at the amino acid level all three loci show strong evidence of balancing selection at some sites. Averaged over polymorphic amino acid sites, DQB1 and DPB1 show similar deviation from neutrality expectations, and both exhibit more balanced polymorphic amino acid sites than DRB1. Across ethnic groups, polymorphisms at many codons show evidence for balancing selection, yet data consistent with directional selection were observed at other codons. Both antigen-binding pocket- and non-pocket-forming amino acid sites show overall deviation from neutrality for all three loci. Only in the case of DRB1 was there a significant difference between pocket- and non-pocket-forming amino acid sites. Our findings indicate that balancing selection at the MHC occurs at the level of polymorphic amino acid residues, and that in many cases this selection is consistent across populations. PMID:10224269

  4. AtWRKY22 promotes susceptibility to aphids and modulates salicylic acid and jasmonic acid signalling

    PubMed Central

    Kloth, Karen J.; Wiegers, Gerrie L.; Busscher-Lange, Jacqueline; van Haarst, Jan C.; Kruijer, Willem; Bouwmeester, Harro J.; Dicke, Marcel; Jongsma, Maarten A.

    2016-01-01

    Aphids induce many transcriptional perturbations in their host plants, but the signalling cascades responsible and the effects on plant resistance are largely unknown. Through a genome-wide association (GWA) mapping study in Arabidopsis thaliana, we identified WRKY22 as a candidate gene associated with feeding behaviour of the green peach aphid, Myzus persicae. The transcription factor WRKY22 is known to be involved in pathogen-triggered immunity, and WRKY22 gene expression has been shown to be induced by aphids. Assessment of aphid population development and feeding behaviour on knockout mutants and overexpression lines showed that WRKY22 increases susceptibility to M. persicae via a mesophyll-located mechanism. mRNA sequencing analysis of aphid-infested wrky22 knockout plants revealed the up-regulation of genes involved in salicylic acid (SA) signalling and down-regulation of genes involved in plant growth and cell-wall loosening. In addition, mechanostimulation of knockout plants by clip cages up-regulated jasmonic acid (JA)-responsive genes, resulting in substantial negative JA–SA crosstalk. Based on this and previous studies, WRKY22 is considered to modulate the interplay between the SA and JA pathways in response to a wide range of biotic and abiotic stimuli. Its induction by aphids and its role in suppressing SA and JA signalling make WRKY22 a potential target for aphids to manipulate host plant defences. PMID:27107291

  5. AtWRKY22 promotes susceptibility to aphids and modulates salicylic acid and jasmonic acid signalling.

    PubMed

    Kloth, Karen J; Wiegers, Gerrie L; Busscher-Lange, Jacqueline; van Haarst, Jan C; Kruijer, Willem; Bouwmeester, Harro J; Dicke, Marcel; Jongsma, Maarten A

    2016-05-01

    Aphids induce many transcriptional perturbations in their host plants, but the signalling cascades responsible and the effects on plant resistance are largely unknown. Through a genome-wide association (GWA) mapping study in Arabidopsis thaliana, we identified WRKY22 as a candidate gene associated with feeding behaviour of the green peach aphid, Myzus persicae The transcription factor WRKY22 is known to be involved in pathogen-triggered immunity, and WRKY22 gene expression has been shown to be induced by aphids. Assessment of aphid population development and feeding behaviour on knockout mutants and overexpression lines showed that WRKY22 increases susceptibility to M. persicae via a mesophyll-located mechanism. mRNA sequencing analysis of aphid-infested wrky22 knockout plants revealed the up-regulation of genes involved in salicylic acid (SA) signalling and down-regulation of genes involved in plant growth and cell-wall loosening. In addition, mechanostimulation of knockout plants by clip cages up-regulated jasmonic acid (JA)-responsive genes, resulting in substantial negative JA-SA crosstalk. Based on this and previous studies, WRKY22 is considered to modulate the interplay between the SA and JA pathways in response to a wide range of biotic and abiotic stimuli. Its induction by aphids and its role in suppressing SA and JA signalling make WRKY22 a potential target for aphids to manipulate host plant defences. PMID:27107291

  6. Small Molecule Signaling Agents: The Integrated Chemistry and Biochemistry of Nitrogen Oxides, Oxides of Carbon, Dioxygen, Hydrogen Sulfide, and Their Derived Species

    PubMed Central

    Fukuto, Jon M.; Carrington, Samantha J.; Tantillo, Dean J.; Harrison, Jason G.; Ignarro, Louis J.; Freeman, Bruce A.; Chen, Andrew; Wink, David A.

    2014-01-01

    Several small molecule species formally known primarily as toxic gases have, over the past 20 years, been shown to be endogenously generated signaling molecules. The biological signaling associated with the small molecules NO, CO, H2S (and the nonendogenously generated O2), and their derived species have become a topic of extreme interest. It has become increasingly clear that these small molecule signaling agents form an integrated signaling web that affects/regulates numerous physiological processes. The chemical interactions between these species and each other or biological targets is an important factor in their roles as signaling agents. Thus, a fundamental understanding of the chemistry of these molecules is essential to understanding their biological/physiological utility. This review focuses on this chemistry and attempts to establish the chemical basis for their signaling functions. PMID:22263838

  7. Critical Role for an Acidic Amino Acid Region in Platelet Signaling by the HemITAM (Hemi-immunoreceptor Tyrosine-based Activation Motif) Containing Receptor CLEC-2 (C-type Lectin Receptor-2)*

    PubMed Central

    Hughes, Craig E.; Sinha, Uma; Pandey, Anjali; Eble, Johannes A.; O'Callaghan, Christopher A.; Watson, Steve P.

    2013-01-01

    CLEC-2 is a member of new family of C-type lectin receptors characterized by a cytosolic YXXL downstream of three acidic amino acids in a sequence known as a hemITAM (hemi-immunoreceptor tyrosine-based activation motif). Dimerization of two phosphorylated CLEC-2 molecules leads to recruitment of the tyrosine kinase Syk via its tandem SH2 domains and initiation of a downstream signaling cascade. Using Syk-deficient and Zap-70-deficient cell lines we show that hemITAM signaling is restricted to Syk and that the upstream triacidic amino acid sequence is required for signaling. Using surface plasmon resonance and phosphorylation studies, we demonstrate that the triacidic amino acids are required for phosphorylation of the YXXL. These results further emphasize the distinct nature of the proximal events in signaling by hemITAM relative to ITAM receptors. PMID:23264619

  8. Antithrombotic activities of ferulic acid via intracellular cyclic nucleotide signaling.

    PubMed

    Hong, Qian; Ma, Zeng-Chun; Huang, Hao; Wang, Yu-Guang; Tan, Hong-Ling; Xiao, Cheng-Rong; Liang, Qian-De; Zhang, Han-Ting; Gao, Yue

    2016-04-15

    Ferulic acid (FA) produces protective effects against cardiovascular dysfunctions. However, the mechanisms of FA is still not known. Here we examined the antithrombotic effects of FA and its potential mechanisms. Anticoagulation assays and platelet aggregation was evaluated in vitro and in vivo. Thromboxane B2 (TXB2), cyclic adenosine monophosphate(cAMP), and cyclic guanosine monophosphate (cGMP) was determined using enzyme immunoassay kits. Nitric oxide (NO) production was measured using the Griess reaction. Protein expression was detected by Western blotting analysis. Oral administration of FA prevented death caused by pulmonary thrombosis and prolonged the tail bleeding and clotting time in mice,while, it did not alter the coagulation parameters, including the activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT). In addition, FA (50-200µM) dose-dependently inhibited platelet aggregation induced by various platelet agonists, including adenosine diphosphate (ADP), thrombin, collagen, arachidonic acid (AA), and U46619. Further, FA attenuated intracellular Ca(2)(+) mobilization and TXB2 production induced by the platelet agonists. FA increased the levels of cAMP and cGMP and phosphorylated vasodilator-stimulated phosphoprotein (VASP) while decreased phospho-MAPK (mitogen-activated protein kinase) and phosphodiesterase (PDE) in washed rat platelets, VASP is a substrate of cyclic nucleotide and PDE is an enzyme family responsible for hydrolysis of cAMP/cGMP. These results suggest that antithrombotic activities of FA may be regulated by inhibition of platelet aggregation, rather than through inhibiting the release of thromboplastin or formation of thrombin. The mechanism of this action may involve activation of cAMP and cGMP signaling. PMID:26948317

  9. Chemical synthesis and characterization of branched oligodeoxyribonucleotides (bDNA) for use as signal amplifiers in nucleic acid quantification assays.

    PubMed Central

    Horn, T; Chang, C A; Urdea, M S

    1997-01-01

    The divergent synthesis of bDNA structures is described. This new type of branched DNA contains one unique oligonucleotide, the primary sequence, covalently attached through a comb-like branching network to many identical copies of a different oligonucleotide, the secondary sequence. The bDNA comb molecules were assembled on a solid support using parameters optimized for bDNA synthesis. The chemistry was used to synthesize bDNA comb molecules containing 15 secondary sequences. The bDNA comb molecules were elaborated by enzymatic ligation into branched amplification multimers, large bDNA molecules (a total of 1068 nt) containing an average of 36 repeated DNA oligomer sequences, each capable of hybridizing specifically to an alkaline phosphatase-labeled oligonucleotide. The bDNA comb molecules were characterized by electrophoretic methods and by controlled cleavage at periodate-cleavable moieties incorporated during synthesis. The branched amplification multimers have been used as signal amplifiers in nucleic acid quantification assays for detection of viral infection. It is possible to detect as few as 50 molecules with bDNA technology. PMID:9365266

  10. Impact of exogenous lipase supplementation on growth, intestinal function, mucosal immune and physical barrier, and related signaling molecules mRNA expression of young grass carp (Ctenopharyngodon idella).

    PubMed

    Liu, Sen; Feng, Lin; Jiang, Wei-Dan; Liu, Yang; Jiang, Jun; Wu, Pei; Zeng, Yun-Yun; Xu, Shu-De; Kuang, Sheng-Yao; Tang, Ling; Tang, Wu-Neng; Zhang, Yong-An; Zhou, Xiao-Qiu

    2016-08-01

    This study investigated the effects of exogenous lipase supplementation on the growth performance, intestinal growth and function, immune response and physical barrier function, and related signaling molecules mRNA expression of young grass carp (Ctenopharyngodon idella). A total of 450 grass carp (255.02 ± 0.34 g) were fed five diets for 60 days. There were 5 dietary treatments that included a normal protein and lipid diet containing 30% crude protein (CP) with 5% ether extract (EE), and the low-protein and high-lipid diets (28% CP, 6% EE) supplemented with graded levels of exogenous lipase supplementation activity at 0, 1193, 2560 and 3730 U/kg diet. The results indicated that compared with a normal protein and lipid diet (30% CP, 5% EE), a low-protein and high-lipid diet (28% CP, 6% EE) (un-supplemented lipase) improved lysozyme activities and complement component 3 contents in the distal intestine (DI), interleukin 10 mRNA expression in the proximal intestine (PI), and glutathione S-transferases activity and glutathione content in the intestine of young grass carp. In addition, in low-protein and high-lipid diets, optimal exogenous lipase supplementation significantly increased acid phosphatase (ACP) activities and complement component 3 (C3) contents (P < 0.05), up-regulated the relative mRNA levels of antimicrobial peptides (liver expressed antimicrobial peptide 2 and hepcidin) and anti-inflammatory cytokines (interleukin 10 and transforming growth factor β1) and signaling molecules inhibitor protein-κBα (IκBα) and target of rapamycin (TOR) (P < 0.05), down-regulated the mRNA levels of pro-inflammatory cytokines (tumor necrosis factor α, interleukin 8, interferon γ2, and interleukin 1β), and signaling molecules (nuclear factor kappa B p65, IκB kinase β, IκB kinase γ) (P < 0.05) in the intestine of young grass carp. Moreover, optimal exogenous lipase supplementation significantly decreased reactive oxygen species (ROS), malondialdehyde

  11. Nucleic Acid Chaperone Activity of HIV-1 NC Proteins Investigated by Single Molecule DNA Stretching

    NASA Astrophysics Data System (ADS)

    Williams, Mark C.; Gorelick, Robert J.; Musier-Forsyth, Karin; Bloomfield, Victor A.

    2002-03-01

    HIV-1 Nucleocapsid Protein (NC) is a nucleic acid chaperone protein that is responsible for facilitating numerous nucleic acid rearrangements throughout the reverse transcription cycle of HIV-1. To understand the mechanism of NC’s chaperone function, we carried out single molecule DNA stretching studies in the presence of NC and mutant forms of NC. Using an optical tweezers instrument, we stretch single DNA molecules from the double-stranded helical state to the single-stranded (coil) state. Based on the observed cooperativity of DNA force-induced melting, we find that the fraction of melted base pairs at room temperature is increased dramatically in the presence of NC. Thus, upon NC binding, increased thermal fluctuations cause continuous melting and reannealing of base pairs so that DNA strands are able to rapidly sample configurations in order to find the lowest energy state. While NC destabilizes the double-stranded form of DNA, a mutant form of NC that lacks the zinc finger structures does not. DNA stretching experiments carried out in the presence of NC variants containing more subtle changes in the zinc finger structures were conducted to elucidate the contribution of each individual finger to NC’s chaperone activity, and these results will be reported.

  12. Insulin Signaling in Liver and Adipose Tissues in Periparturient Dairy Cows Supplemented with Dietary Nicotinic Acid.

    PubMed

    Kinoshita, Asako; Kenéz, Ákos; Locher, Lena; Meyer, Ulrich; Dänicke, Sven; Rehage, Jürgen; Huber, Korinna

    2016-01-01

    The glucose homeostasis in dairy cattle is very well controlled, in line with the metabolic adaptation during the periparturient period. Former studies showed that nicotinic acid (NA) lowered plasma non-esterified fatty acids (NEFA) concentrations and increased insulin sensitivity in dairy cows. Thus, the purpose of this study was to investigate whether the expression of proteins involved in hepatic and adipose insulin signaling and protein expression of hepatic glucose transporter 2 (GLUT2) were affected by dietary NA and dietary concentrate intake in periparturient dairy cows. Twenty pluriparous German Holstein cows were fed with the same diet from about 21 days before the expected calving date (d-21) to calving. After calving, cows were randomly assigned in 4 groups and fed with diets different in concentrate proportion ("HC" with 60:40% or "LC" with 30:70% concentrate-to-roughage ratio) and supplemented with NA (24 g/day) (NA) or without (CON) until d21. Biopsy samples were taken from the liver, subcutaneous (SCAT) and retroperitoneal (RPAT) adipose tissues at d-21 and d21. Protein expression of insulin signaling molecules (insulin receptor (INSR), phosphatidylinositol-3-kinase (PI3K), protein kinase Cζ (PKCζ)) and hepatic GLUT2 was measured by Western Blotting. The ratio of protein expression at d21/at d-21 was calculated and statistically evaluated for the effects of time and diet. Cows in HC had significantly higher dietary energy intake than cows in LC. In RPAT a decrease in PI3K and PKCζ expression was found in all groups, irrespectively of diet. In the liver, the GLUT2 expression was significantly lower in cows in NA compared with cows in CON. In conclusion, insulin signaling might be decreased in RPAT over time without any effect of diet. NA was able to modulate hepatic GLUT2 expression, but its physiological role is unclear. PMID:26766039

  13. Insulin Signaling in Liver and Adipose Tissues in Periparturient Dairy Cows Supplemented with Dietary Nicotinic Acid

    PubMed Central

    Kinoshita, Asako; Kenéz, Ákos; Locher, Lena; Meyer, Ulrich; Dänicke, Sven; Rehage, Jürgen; Huber, Korinna

    2016-01-01

    The glucose homeostasis in dairy cattle is very well controlled, in line with the metabolic adaptation during the periparturient period. Former studies showed that nicotinic acid (NA) lowered plasma non-esterified fatty acids (NEFA) concentrations and increased insulin sensitivity in dairy cows. Thus, the purpose of this study was to investigate whether the expression of proteins involved in hepatic and adipose insulin signaling and protein expression of hepatic glucose transporter 2 (GLUT2) were affected by dietary NA and dietary concentrate intake in periparturient dairy cows. Twenty pluriparous German Holstein cows were fed with the same diet from about 21 days before the expected calving date (d-21) to calving. After calving, cows were randomly assigned in 4 groups and fed with diets different in concentrate proportion (“HC” with 60:40% or “LC” with 30:70% concentrate-to-roughage ratio) and supplemented with NA (24 g/day) (NA) or without (CON) until d21. Biopsy samples were taken from the liver, subcutaneous (SCAT) and retroperitoneal (RPAT) adipose tissues at d-21 and d21. Protein expression of insulin signaling molecules (insulin receptor (INSR), phosphatidylinositol-3-kinase (PI3K), protein kinase Cζ (PKCζ)) and hepatic GLUT2 was measured by Western Blotting. The ratio of protein expression at d21/at d-21 was calculated and statistically evaluated for the effects of time and diet. Cows in HC had significantly higher dietary energy intake than cows in LC. In RPAT a decrease in PI3K and PKCζ expression was found in all groups, irrespectively of diet. In the liver, the GLUT2 expression was significantly lower in cows in NA compared with cows in CON. In conclusion, insulin signaling might be decreased in RPAT over time without any effect of diet. NA was able to modulate hepatic GLUT2 expression, but its physiological role is unclear. PMID:26766039

  14. Bioactive Molecules Released in Food by Lactic Acid Bacteria: Encrypted Peptides and Biogenic Amines

    PubMed Central

    Pessione, Enrica; Cirrincione, Simona

    2016-01-01

    Lactic acid bacteria (LAB) can produce a huge amount of bioactive compounds. Since their elective habitat is food, especially dairy but also vegetal food, it is frequent to find bioactive molecules in fermented products. Sometimes these compounds can have adverse effects on human health such as biogenic amines (tyramine and histamine), causing allergies, hypertensive crises, and headache. However, some LAB products also display benefits for the consumers. In the present review article, the main nitrogen compounds produced by LAB are considered. Besides biogenic amines derived from the amino acids tyrosine, histidine, phenylalanine, lysine, ornithine, and glutamate by decarboxylation, interesting peptides can be decrypted by the proteolytic activity of LAB. LAB proteolytic system is very efficient in releasing encrypted molecules from several proteins present in different food matrices. Alpha and beta-caseins, albumin and globulin from milk and dairy products, rubisco from spinach, beta-conglycinin from soy and gluten from cereals constitute a good source of important bioactive compounds. These encrypted peptides are able to control nutrition (mineral absorption and oxidative stress protection), metabolism (blood glucose and cholesterol lowering) cardiovascular function (antithrombotic and hypotensive action), infection (microbial inhibition and immunomodulation) and gut-brain axis (opioids and anti-opioids controlling mood and food intake). Very recent results underline the role of food-encrypted peptides in protein folding (chaperone-like molecules) as well as in cell cycle and apoptosis control, suggesting new and positive aspects of fermented food, still unexplored. In this context, the detailed (transcriptomic, proteomic, and metabolomic) characterization of LAB of food interest (as starters, biocontrol agents, nutraceuticals, and probiotics) can supply a solid evidence-based science to support beneficial effects and it is a promising approach as well to obtain

  15. Bioactive Molecules Released in Food by Lactic Acid Bacteria: Encrypted Peptides and Biogenic Amines.

    PubMed

    Pessione, Enrica; Cirrincione, Simona

    2016-01-01

    Lactic acid bacteria (LAB) can produce a huge amount of bioactive compounds. Since their elective habitat is food, especially dairy but also vegetal food, it is frequent to find bioactive molecules in fermented products. Sometimes these compounds can have adverse effects on human health such as biogenic amines (tyramine and histamine), causing allergies, hypertensive crises, and headache. However, some LAB products also display benefits for the consumers. In the present review article, the main nitrogen compounds produced by LAB are considered. Besides biogenic amines derived from the amino acids tyrosine, histidine, phenylalanine, lysine, ornithine, and glutamate by decarboxylation, interesting peptides can be decrypted by the proteolytic activity of LAB. LAB proteolytic system is very efficient in releasing encrypted molecules from several proteins present in different food matrices. Alpha and beta-caseins, albumin and globulin from milk and dairy products, rubisco from spinach, beta-conglycinin from soy and gluten from cereals constitute a good source of important bioactive compounds. These encrypted peptides are able to control nutrition (mineral absorption and oxidative stress protection), metabolism (blood glucose and cholesterol lowering) cardiovascular function (antithrombotic and hypotensive action), infection (microbial inhibition and immunomodulation) and gut-brain axis (opioids and anti-opioids controlling mood and food intake). Very recent results underline the role of food-encrypted peptides in protein folding (chaperone-like molecules) as well as in cell cycle and apoptosis control, suggesting new and positive aspects of fermented food, still unexplored. In this context, the detailed (transcriptomic, proteomic, and metabolomic) characterization of LAB of food interest (as starters, biocontrol agents, nutraceuticals, and probiotics) can supply a solid evidence-based science to support beneficial effects and it is a promising approach as well to obtain

  16. Regulatory signals for intestinal amino acid transporters and peptidases

    SciTech Connect

    Ferraris, R.P.; Kwan, W.W.; Diamond, J. )

    1988-08-01

    Dietary protein ultimately regulates many processes involved in protein digestion, but it is often unclear whether proteins themselves, peptides, or amino acids (AAs) are the proximate regulatory signal. Hence the authors compared several processes involved in protein digestion in mice adapted to one of three rations, identical except for containing 54% of either casein, a partial hydrolysate of casein, or a free AA mixture simulating a complete hydrolysate of casein. The authors measured brush-border uptakes of seven AAs that variously serve as substrates for four AA transporters, and brush-border and cytosolic activities of four peptidases. The three rations yielded essentially the same AA uptake rates. Peptidase activities tended to be lower on the AA ration than on the protein ration. In other studies, all three rations yielded the same rates of brush-border peptide uptake; protein is only modestly more effective than AAs at inducing synthesis of pancreatic proteases; and, depending on the animal species, protein is either much less or much more effective than AAs at stimulating release of cholecystokinin and hence of pancreatic enzymes. Thus the regulators of each process involved in protein digestion are not necessarily that process's substrate.

  17. Phosphatidic Acid-Mediated Signaling Regulates Microneme Secretion in Toxoplasma.

    PubMed

    Bullen, Hayley E; Jia, Yonggen; Yamaryo-Botté, Yoshiki; Bisio, Hugo; Zhang, Ou; Jemelin, Natacha Klages; Marq, Jean-Baptiste; Carruthers, Vern; Botté, Cyrille Y; Soldati-Favre, Dominique

    2016-03-01

    The obligate intracellular lifestyle of apicomplexan parasites necessitates an invasive phase underpinned by timely and spatially controlled secretion of apical organelles termed micronemes. In Toxoplasma gondii, extracellular potassium levels and other stimuli trigger a signaling cascade culminating in phosphoinositide-phospholipase C (PLC) activation, which generates the second messengers diacylglycerol (DAG) and IP3 and ultimately results in microneme secretion. Here we show that a delicate balance between DAG and its downstream product, phosphatidic acid (PA), is essential for controlling microneme release. Governing this balance is the apicomplexan-specific DAG-kinase-1, which interconverts PA and DAG, and whose depletion impairs egress and causes parasite death. Additionally, we identify an acylated pleckstrin-homology (PH) domain-containing protein (APH) on the microneme surface that senses PA during microneme secretion and is necessary for microneme exocytosis. As APH is conserved in Apicomplexa, these findings highlight a potentially widely used mechanism in which key lipid mediators regulate microneme exocytosis. PMID:26962945

  18. The role of polymorphic amino acids of the MHC molecule in the selection of the T cell repertoire

    SciTech Connect

    Bhayani, H.R.; Hedrick, S.M. )

    1991-02-15

    Allelic variants of MHC molecules expressed on cells of the thymus affect the selection and the specificity of the T cell repertoire. The selection is based on either the direct recognition by the TCR of the MHC molecules, or the recognition of a complex determinant formed by self-peptides bound to MHC molecules. In an analysis of the T cell repertoire in bone marrow chimeras that express allelic forms of MHC class II molecules in the thymus epithelium, we find that amino acid substitutions that are predicted to affect peptide binding influence the selection of the T cell repertoire during thymic selection.

  19. Intracellular Signaling Molecules Activated by Epstein-Barr Virus for Induction of Interferon Regulatory Factor 7

    PubMed Central

    Zhang, Luwen; Wu, Lihong; Hong, Ke; Pagano, Joseph S.

    2001-01-01

    Epstein-Barr virus (EBV) latent membrane protein 1 (LMP-1) is the principal oncogenic protein in the EBV transformation process. LMP-1 induces the expression of interferon regulatory factor 7 (IRF-7) and activates IRF-7 protein by phosphorylation and nuclear translocation. LMP-1 is an integral membrane protein with two regions in its C terminus that initiate signaling processes, the C-terminal activator regions 1 (CTAR-1) and CTAR-2. Here, genetic analysis of LMP-1 has determined that the PXQXT motif that governs the interaction between LMP-1 CTAR-1 and tumor necrosis factor receptor-associated factors (TRAFs) is needed to induce the expression of IRF-7. Mutations in the PXQXT motif in CTAR-1 that disrupt the interaction between LMP-1 and TRAFs abolished the induction of IRF-7. Also, dominant-negative mutants of TRAFs inhibited the induction of IRF-7 by CTAR-1. The last three amino acids (YYD) of CTAR-2 are also important for the induction of IRF-7. When both PXQXT and YYD were mutated (LMP-DM), the LMP-1 mutant failed to induce IRF-7. Also, LMP-DM blocked the induction of IRF-7 by wild-type LMP-1. These data strongly suggest that both CTAR-1 and CTAR-2 of LMP-1 independently induce the expression of IRF-7. In addition, NF-κB is involved in the induction of IRF-7. A superrepressor of IκB (sr-IκB) could block the induction of IRF-7 by LMP-1, and overexpression of NF-κB (p65 plus p50) could induce the expression of IRF-7. In addition, we have found that human IRF-7 is a stable protein, and sodium butyrate, a modifier of chromatin structure, induces IRF-7. PMID:11711629

  20. Constitutive and Hyperresponsive Signaling by Mutant Forms of Saccharomyces cerevisiae Amino Acid Sensor Ssy1†

    PubMed Central

    Gaber, Richard F.; Ottow, Kim; Andersen, Helge A.; Kielland-Brandt, Morten C.

    2003-01-01

    Sensing of extracellular amino acids results in transcriptional induction of amino acid permease genes in yeast. Ssy1, a membrane protein resembling amino acid permeases, is required for signaling but is apparently unable to transport amino acids and is thus believed to be a sensor. By using a novel genetic screen in which potassium uptake was made dependent on amino acid signaling, we obtained gain-of-function mutations in SSY1. Some alleles confer inducer-independent signaling; others increase the apparent affinity for inducers. The results reveal that amino acid transport is not required for signaling and support the notion that sensing by Ssy1 occurs via its direct interaction with extracellular amino acids. PMID:14555474

  1. Signal transduction pathways mediated by PECAM-1: new roles for an old molecule in platelet and vascular cell biology.

    PubMed

    Newman, Peter J; Newman, Debra K

    2003-06-01

    Recent studies of platelet endothelial cell adhesion molecule-1 (PECAM-1 [CD31])-deficient mice have revealed that this molecule plays an important role in controlling the activation and survival of cells on which it is expressed. In this review, we focus on the complex cytoplasmic domain of PECAM-1 and describe what is presently known about its structure, posttranslational modifications, and binding partners. In addition, we summarize findings that implicate PECAM-1 as an inhibitor of cellular activation via protein tyrosine kinase-dependent signaling pathways, an activator of integrins, and a suppressor of cell death via pathways that depend on damage to the mitochondria. The challenge of future research will be to bridge our understanding of the functional and biochemical properties of PECAM-1 by establishing mechanistic links between signals transduced by the PECAM-1 cytoplasmic domain and discrete cellular responses. PMID:12689916

  2. Electrophilic nitro-fatty acids inhibit vascular inflammation by disrupting LPS-dependent TLR4 signalling in lipid rafts

    PubMed Central

    Villacorta, Luis; Chang, Lin; Salvatore, Sonia R.; Ichikawa, Tomonaga; Zhang, Jifeng; Petrovic-Djergovic, Danica; Jia, Lingyun; Carlsen, Harald; Schopfer, Francisco J.; Freeman, Bruce A.; Chen, Y. Eugene

    2013-01-01

    Aims Electrophilic fatty acid nitroalkene derivatives, products of unsaturated fatty acid nitration, exert long-term cardiovascular protection in experimental models of metabolic and cardiovascular diseases. The goal of this study is to examine the effects of nitro-fatty acids in the regulation of upstream signalling events in nuclear factor-κB (NF-κB) activation and determine whether low-dose acute administration of nitro-fatty acids reduces vascular inflammation in vivo. Methods and results Using NF-κB-luciferase transgenic mice, it was determined that pre-emptive treatment with nitro-oleic acid (OA-NO2), but not oleic acid (OA) inhibits lipopolysaccharide (LPS)-induced NF-κB activation both in vivo and in isolated macrophages. Acute intravenous administration of OA-NO2 was equally effective to inhibit leukocyte recruitment to the vascular endothelium assessed by intravital microscopy and significantly reduces aortic expression of adhesion molecules. An acute treatment with OA-NO2 in vivo yielding nanomolar concentrations in plasma, is sufficient to inhibit LPS-induced Toll-like receptor 4 (TLR4)-induced cell surface expression in leukocytes and NF-κB activation. In vitro experiments reveal that OA-NO2 suppresses LPS-induced TLR4 signalling, inhibitor of κB (IκBα) phosphorylation and ubiquitination, phosphorylation of the IκB kinase (IKK), impairing the recruitment of the TLR4 and TNF receptor associated factor 6 (TRAF6) to the lipid rafts compartments. Conclusion These studies demonstrate that acute administration of nitro-fatty acids is effective to reduce vascular inflammation in vivo. These findings reveal a direct role of nitro-fatty acids in the disruption of the TLR4 signalling complex in lipid rafts, upstream events of the NF-κB pathway, leading to resolution of pro-inflammatory activation of NF-κB in the vasculature. PMID:23334216

  3. Investigation of signaling molecules and metabolites found in crustacean hemolymph via in vivo microdialysis using a multifaceted mass spectrometric platform.

    PubMed

    Jiang, Shan; Liang, Zhidan; Hao, Ling; Li, Lingjun

    2016-04-01

    Neurotransmitters (NTs) are endogenous signaling molecules that play an important role in regulating various physiological processes in animals. Detection of these chemical messengers is often challenging due to their low concentration levels and fast degradation rate in vitro. In order to address these challenges, herein we employed in vivo microdialysis (MD) sampling to study NTs in the crustacean model Cancer borealis. Multifaceted separation tools, such as CE and ion mobility mass spectrometry (MS) were utilized in this work. Small molecules were separated by different mechanisms and detected by MALDI mass spectrometric imaging (MALDI-MSI). Performance of this separation-based MSI platform was also compared to LC-ESI-MS. By utilizing both MALDI and ESI-MS, a total of 208 small molecule NTs and metabolites were identified, of which 39 were identified as signaling molecules secreted in vivo. In addition, the inherent property of sub microscale sample consumption using CE enables shorter time of MD sample collection. Temporal resolution of MD was improved by approximately tenfold compared to LC-ESI-MS, indicating the significant advantage of applying separation-assisted MALDI-MS imaging platform. PMID:26691021

  4. Opposing effects of bile acids deoxycholic acid and ursodeoxycholic acid on signal transduction pathways in oesophageal cancer cells.

    PubMed

    Abdel-Latif, Mohamed M; Inoue, Hiroyasu; Reynolds, John V

    2016-09-01

    Ursodeoxycholic acid (UDCA) was reported to reduce bile acid toxicity, but the mechanisms underlying its cytoprotective effects are not fully understood. The aim of the present study was to examine the effects of UDCA on the modulation of deoxycholic acid (DCA)-induced signal transduction in oesophageal cancer cells. Nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) activity was assessed using a gel shift assay. NF-κB activation and translocation was performed using an ELISA-based assay and immunofluorescence analysis. COX-2 expression was analysed by western blotting and COX-2 promoter activity was assessed by luciferase assay. DCA induced NF-κB and AP-1 DNA-binding activities in SKGT-4 and OE33 cells. UDCA pretreatment inhibited DCA-induced NF-κB and AP-1 activation and NF-κB translocation. This inhibitory effect was coupled with a blockade of IκB-α degradation and inhibition of phosphorylation of IKK-α/β and ERK1/2. Moreover, UDCA pretreatment inhibited COX-2 upregulation. Using transient transfection of the COX-2 promoter, UDCA pretreatment abrogated DCA-induced COX-2 promoter activation. In addition, UDCA protected oesophageal cells from the apoptotic effects of deoxycholate. Our findings indicate that UDCA inhibits DCA-induced signalling pathways in oesophageal cancer cells. These data indicate a possible mechanistic role for the chemopreventive actions of UDCA in oesophageal carcinogenesis. PMID:26378497

  5. High Mobility Group Box Protein 1 (HMGB1)-Partner Molecule Complexes Enhance Cytokine Production by Signaling Through the Partner Molecule Receptor

    PubMed Central

    Hreggvidsdóttir, Hulda Sigridur; Lundberg, Anna M; Aveberger, Ann-Charlotte; Klevenvall, Lena; Andersson, Ulf; Harris, Helena Erlandsson

    2012-01-01

    The nuclear protein high mobility group box protein 1 (HMGB1) promotes inflammation upon extracellular release. HMGB1 induces proinflammatory cytokine production in macrophages via Toll-like receptor (TLR)-4 signaling in a redox-dependent fashion. Independent of its redox state and endogenous cytokine-inducing ability, HMGB1 can form highly immunostimulatory complexes by interaction with certain proinflammatory mediators. Such complexes have the ability to enhance the induced immune response up to 100-fold, compared with induction by the ligand alone. To clarify the mechanisms for these strong synergistic effects, we studied receptor requirements. Interleukin (IL)-6 production was assessed in supernatants from cultured peritoneal macrophages from mice each deficient in one of the HMGB1 receptors (receptor for advanced glycation end products [RAGE], TLR2 or TLR4) or from wild-type controls. The cultures were stimulated with the TLR4 ligand lipopolysaccaride (LPS), the TLR2 ligand Pam3CysSerLys4 (Pam3CSK4), noninflammatory HMGB1 or each TLR ligand in complex with noninflammatory HMGB1. The activity of the HMGB1-TLR ligand complexes relied on engagement of the same receptor as for the noncomplexed TLR ligand, since HMGB1-LPS complexes used TLR4 and HMGB1-Pam3CSK4 complexes used TLR2. Deletion of any of the intracellular adaptor molecules used by TLR2 (myeloid differentiation factor-88 [MyD88], TIR domain–containing adaptor protein [TIRAP]) or TLR4 (MyD88, TIRAP, TIR domain–containing adaptor-inducing interferon-β [TRIF], TRIF-related adaptor molecule [TRAM]) had similar effects on HMGB1 complex activation compared with noncomplexed LPS or Pam3CSK4. This result implies that the enhancing effects of HMGB1-partner molecule complexes are not regulated by the induction of additional signaling cascades. Elucidating HMGB1 receptor usage in processes where HMGB1 acts alone or in complex with other molecules is essential for the understanding of basic HMGB1 biology and

  6. Single-Molecule Imaging Reveals That Argonaute Reshapes the Binding Properties of Its Nucleic Acid Guides

    PubMed Central

    Salomon, William E.; Jolly, Samson M.; Moore, Melissa J.; Zamore, Phillip D.; Serebrov, Victor

    2015-01-01

    SUMMARY Argonaute proteins repress gene expression and defend against foreign nucleic acids using short RNAs or DNAs to specify the correct target RNA or DNA sequence. We have developed single-molecule methods to analyze target binding and cleavage mediated by the Argonaute:guide complex, RISC. We find that both eukaryotic and prokaryotic Argonaute proteins reshape the fundamental properties of RNA:RNA, RNA:DNA, and DNA:DNA hybridization: a small RNA or DNA bound to Argonaute as a guide no longer follows the well-established rules by which oligonucleotides find, bind, and dissociate from complementary nucleic acid sequences. Argonautes distinguish substrates from targets with similar complementarity. Mouse AGO2, for example, binds tighter to miRNA targets than its RNAi cleavage product, even though the cleaved product contains more base pairs. By re-writing the rules for nucleic acid hybridization, Argonautes allow oligonucleotides to serve as specificity determinants with thermodynamic and kinetic properties more typical of RNA-binding proteins than of RNA or DNA. PMID:26140592

  7. Single-Molecule Imaging Reveals that Argonaute Reshapes the Binding Properties of Its Nucleic Acid Guides.

    PubMed

    Salomon, William E; Jolly, Samson M; Moore, Melissa J; Zamore, Phillip D; Serebrov, Victor

    2015-07-01

    Argonaute proteins repress gene expression and defend against foreign nucleic acids using short RNAs or DNAs to specify the correct target RNA or DNA sequence. We have developed single-molecule methods to analyze target binding and cleavage mediated by the Argonaute:guide complex, RISC. We find that both eukaryotic and prokaryotic Argonaute proteins reshape the fundamental properties of RNA:RNA, RNA:DNA, and DNA:DNA hybridization—a small RNA or DNA bound to Argonaute as a guide no longer follows the well-established rules by which oligonucleotides find, bind, and dissociate from complementary nucleic acid sequences. Argonautes distinguish substrates from targets with similar complementarity. Mouse AGO2, for example, binds tighter to miRNA targets than its RNAi cleavage product, even though the cleaved product contains more base pairs. By re-writing the rules for nucleic acid hybridization, Argonautes allow oligonucleotides to serve as specificity determinants with thermodynamic and kinetic properties more typical of RNA-binding proteins than of RNA or DNA. PMID:26140592

  8. Differential regulation of EGFR-MAPK signaling by deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA) in colon cancer

    PubMed Central

    Centuori, Sara M.; Martinez, Jesse D.

    2014-01-01

    A high fat diet coincides with elevated levels of bile acids. This elevation of bile acids, particularly deoxycholic acid (DCA), has been strongly associated with the development of colon cancer. Conversely, ursodeoxycholic acid (UDCA) may have chemopreventive properties. Although structurally similar, DCA and UDCA present different biological and pathological effects in colon cancer progression. The differential regulation of cancer by these two bile acids is not yet fully understood. However, one possible explanation for their diverging effects is their ability to differentially regulate signaling pathways involved in the multistep progression of colon cancer, such as the epidermal growth factor receptor (EGFR) mitogen-activated protein kinase (MAPK) pathway. This review will examine the biological effects of DCA and UDCA on colon cancer development, as well as the diverging effects of these bile acids on the oncogenic signaling pathways that play a role in colon cancer development, with a particular emphasis on bile acid regulation of the EGFR-MAPK pathway. PMID:25027205

  9. Propaedeutic study for the delivery of nucleic acid-based molecules from PLGA microparticles and stearic acid nanoparticles

    PubMed Central

    Grassi, G; Coceani, N; Farra, R; Dapas, B; Racchi, G; Fiotti, N; Pascotto, A; Rehimers, B; Guarnieri, G; Grassi, M

    2006-01-01

    We studied the mechanism governing the delivery of nucleic acid-based drugs (NABD) from microparticles and nanoparticles in zero shear conditions, a situation occurring in applications such as in situ delivery to organ parenchyma. The delivery of a NABD molecule from poly(DL-lactide-co-glycolide) (PLGA) microparticles and stearic acid (SA) nanoparticles was studied using an experimental apparatus comprising a donor chamber separated from the receiver chamber by a synthetic membrane. A possible toxic effect on cell biology, as evaluated by studying cell proliferation, was also conducted for just PLGA microparticles. A mathematical model based on the hypothesis that NABD release from particles is due to particle erosion was used to interpret experimental release data. Despite zero shear conditions imposed in the donor chamber, particle erosion was the leading mechanism for NABD release from both PLGA microparticles and SA nanoparticles. PLGA microparticle erosion speed is one order of magnitude higher than that of competing to SA nanoparticles. Finally, no deleterious effects of PLGA microparticles on cell proliferation were detected. Thus, the data here reported can help optimize the delivery systems aimed at release of NABD from micro- and nanoparticles. PMID:17722283

  10. Antitumor activity of gambogic acid on NCI-H1993 xenografts via MET signaling pathway downregulation

    PubMed Central

    LI, DONGLEI; YANG, HUIWEI; LI, RUNPU; WANG, YANLI; WANG, WEIJUN; LI, DONGJIE; MA, SHAOLIN; ZHANG, XUYU

    2015-01-01

    The present study aimed to investigate the anti-tumor mechanisms of gambogic acid (GA) on NCI-H1993 xenografts in vivo. Non-small cell lung carcinoma NCI-H1993 cells, which harbor a MET gene amplification, were subcutaneously injected into athymic nude mice. The mice were randomly assigned to treatment with 10, 20 or 30 mg/kg GA for 3 weeks. At the end of the efficacy study, all the mice were sacrificed and the tumor tissues were subjected to western blot analysis and immunohistochemical (IHC) staining. GA inhibited NCI-H1993 xenograft tumor growth in a dose-dependent manner. Western blot analysis demonstrated that expression of phosphorylated (p)-MET and its downstream signaling molecules p-AKT and p-ERK1/2 were significantly inhibited by GA. IHC analysis of Ki-67 expression demonstrated that GA treatment resulted in dose-dependent inhibition of tumor cell proliferation. GA exerted antitumor effects on NCI-H1993 xenografts in vivo by direct regulation of the MET signaling pathway. Theses antitumor effects were primarily a result of its anti-proliferation function. PMID:26722245

  11. Acetyl salicylic acid attenuates cardiac hypertrophy through Wnt signaling.

    PubMed

    Gitau, Samuel Chege; Li, Xuelian; Zhao, Dandan; Guo, Zhenfeng; Liang, Haihai; Qian, Ming; Lv, Lifang; Li, Tianshi; Xu, Bozhi; Wang, Zhiguo; Zhang, Yong; Xu, Chaoqian; Lu, Yanjie; Du, Zhiming; Shan, Hongli; Yang, Baofeng

    2015-12-01

    Ventricular hypertrophy is a powerful and independent predictor of cardiovascular morbid events. The vascular properties of low-dose acetyl salicylic acid (aspirin) provide cardiovascular benefits through the irreversible inhibition of platelet cyclooxygenase 1; however, the possible anti-hypertrophic properties and potential mechanism of aspirin have not been investigated in detail. In this study, healthy wild-type male mice were randomly divided into three groups and subjected to transverse aortic constriction (TAC) or sham operation. The TAC-operated mice were treated with the human equivalent of low-dose aspirin (10 mg·kg(-1)·d(-1)); the remaining mice received an equal amount of phosphate buffered saline with 0.65% ethanol, which was used as a vehicle. A cardiomyocyte hypertrophy model induced by angiotensin II (10 nmol·L(-1)) was treated with the human equivalent of low (10 or 100 μmol·L(-1)) and high (1000 μmol·L(-1)) aspirin concentrations in plasma. Changes in the cardiac structure and function were assessed through echocardiography and transmission electron microscopy. Gene expression was determined through RT-PCR and western blot analysis. Results indicated that aspirin treatment abrogated the increased thickness of the left ventricular anterior and posterior walls, the swelling of mitochondria, and the increased surface area in in vivo and in vitro hypertrophy models. Aspirin also normalized the upregulated hypertrophic biomarkers, β-myosin heavy chain (β-MHC), atrial natriuretic peptide (ANP), and b-type natriuretic peptide (BNP). Aspirin efficiently reversed the upregulation of β-catenin and P-Akt expression and the TAC- or ANG II-induced downregulation of GSK-3β. Therefore, low-dose aspirin possesses significant anti-hypertrophic properties at clinically relevant concentrations for anti-thrombotic therapy. The downregulation of β-catenin and Akt may be the underlying signaling mechanism of the effects of aspirin. PMID:26626190

  12. Changes in the Common Bean Transcriptome in Response to Secreted and Surface Signal Molecules of Rhizobium etli1[OPEN

    PubMed Central

    Dalla Via, Virginia; Narduzzi, Candela; Aguilar, Orlando Mario; Zanetti, María Eugenia; Blanco, Flavio Antonio

    2015-01-01

    Establishment of nitrogen-fixing symbiosis requires the recognition of rhizobial molecules to initiate the development of nodules. Using transcriptional profiling of roots inoculated with mutant strains defective in the synthesis of Nod Factor (NF), exopolysaccharide (EPS), or lipopolysaccharide (LPS), we identified 2,606 genes from common bean (Phaseolus vulgaris) that are differentially regulated at early stages of its interaction with Rhizobium etli. Many transcription factors from different families are modulated by NF, EPS, and LPS in different combinations, suggesting that the plant response depends on the integration of multiple signals. Some receptors identified as differentially expressed constitute excellent candidates to participate in signal perception of molecules derived from the bacteria. Several components of the ethylene signal response, a hormone that plays a negative role during early stages of the process, were down-regulated by NF and LPS. In addition, genes encoding proteins involved in small RNA-mediated gene regulation were regulated by these signal molecules, such as Argonaute7, a specific component of the trans-acting short interfering RNA3 pathway, an RNA-dependent RNA polymerase, and an XH/XP domain-containing protein, which is part of the RNA-directed DNA methylation. Interestingly, a number of genes encoding components of the circadian central oscillator were down-regulated by NF and LPS, suggesting that a root circadian clock is adjusted at early stages of symbiosis. Our results reveal a complex interaction of the responses triggered by NF, LPS, and EPS that integrates information of the signals present in the surface or secreted by rhizobia. PMID:26282238

  13. Micelle-assisted signaling of peracetic acid by the oxidation of pyreneboronic acid via monomer-excimer switching.

    PubMed

    Choi, Jiyoung; Lee, Hyo Jin; Cho, Min Jeoung; Chang, Suk-Kyu

    2015-08-15

    A simple fluorescent probe for the industrial oxidant peracetic acid (PAA) was investigated. PAA-assisted oxidative conversion of pyrene-1-boronic acid into 1-hydroxypyrene was used as the signaling tool. Pyreneboronic acid was found to display selective signaling behavior, being more responsive to PAA than to other commonly used practical oxidants such as H2O2 and HOCl. The changes in pyrene monomer fluorescence to excimer were used in the quantitative analysis of PAA. When using the surfactant hexadecyltrimethylammonium bromide as a micellar additive, the signaling of PAA was markedly enhanced. Selective fluorescence signaling of PAA by pyrene-1-boronic acid with a detection limit of 1.5×10(-6)M in aqueous environment was successfully achieved. PMID:25966389

  14. A phenotypic screen in zebrafish identifies a novel small-molecule inducer of ectopic tail formation suggestive of alterations in non-canonical Wnt/PCP signaling.

    PubMed

    Gebruers, Evelien; Cordero-Maldonado, María Lorena; Gray, Alexander I; Clements, Carol; Harvey, Alan L; Edrada-Ebel, Ruangelie; de Witte, Peter A M; Crawford, Alexander D; Esguerra, Camila V

    2013-01-01

    Zebrafish have recently emerged as an attractive model for the in vivo bioassay-guided isolation and characterization of pharmacologically active small molecules of natural origin. We carried out a zebrafish-based phenotypic screen of over 3000 plant-derived secondary metabolite extracts with the goal of identifying novel small-molecule modulators of the BMP and Wnt signaling pathways. One of the bioactive plant extracts identified in this screen - Jasminum gilgianum, an Oleaceae species native to Papua New Guinea - induced ectopic tails during zebrafish embryonic development. As ectopic tail formation occurs when BMP or non-canonical Wnt signaling is inhibited during the tail protrusion process, we suspected a constituent of this extract to act as a modulator of these pathways. A bioassay-guided isolation was carried out on the basis of this zebrafish phenotype, identifying para-coumaric acid methyl ester (pCAME) as the active compound. We then performed an in-depth phenotypic analysis of pCAME-treated zebrafish embryos, including a tissue-specific marker analysis of the secondary tails. We found pCAME to synergize with the BMP-inhibitors dorsomorphin and LDN-193189 in inducing ectopic tails, and causing convergence-extension defects in compound-treated embryos. These results indicate that pCAME may interfere with non-canonical Wnt signaling. Inhibition of Jnk, a downstream target of Wnt/PCP signaling (via morpholino antisense knockdown and pharmacological inhibition with the kinase inhibitor SP600125) phenocopied pCAME-treated embryos. However, immunoblotting experiments revealed pCAME to not directly inhibit Jnk-mediated phosphorylation of c-Jun, suggesting additional targets of SP600125, and/or other pathways, as possibly being involved in the ectopic tail formation activity of pCAME. Further investigation of pCAME's mechanism of action will help determine this compound's pharmacological utility. PMID:24349481

  15. 'Smelling' the cerebrospinal fluid: olfactory signaling molecules are expressed in and mediate chemosensory signaling from the choroid plexus.

    PubMed

    Gonçalves, Isabel; Hubbard, Peter C; Tomás, Joana; Quintela, Telma; Tavares, Gabriela; Caria, Sandra; Barreiros, Daniela; Santos, Cecília R A

    2016-05-01

    The olfactory-type signaling machinery has been known to be involved not only in odorant detection but also in other tissues with unsuspected sensory roles. As a barrier, the choroid plexus (CP) is an active participant in the monitoring of the cerebrospinal fluid (CSF), promptly responding to alterations in its composition. We hypothesized that olfactory signaling could be active in CP, contributing to the surveillance of the CSF composition. We determined the mRNA and protein expression of the major components of the olfactory transduction pathway in the rat CP, including odorant receptors, the olfactory G-protein (Gαolf), adenylate cyclase 3 and cyclic nucleotide-gated channel 2. The functionality of the transduction pathway and the intracellular mechanisms involved were analyzed by DC field potential recording electrophysiological analysis, in an ex vivo CP-brain setup, using polyamines as stimuli and blockers of the downstream signaling pathways. Concentration-dependent responses were obtained for the polyamines studied (cadaverine, putrescine, spermine and spermidine), all known to be present in the CSF. Transfection of a CP epithelial cell line with siRNA against Gαolf effectively knocked down protein expression and reduced the CP cells' response to spermine. Thus, the key components of the olfactory chemosensory apparatus are present and are functional in murine CP, and polyamines seem to trigger both the cAMP and the phospholipase C-inositol 1,4,5-trisphosphate pathways. Olfactory-like chemosensory signaling may be an essential component of the CP chemical surveillance apparatus to detect alterations in the CSF composition, and to elicit responses to modulate and maintain brain homeostasis. PMID:26934374

  16. Gold Nanoparticles Surface Plasmon Resonance Enhanced Signal for the Detection of Small Molecules on Split-Aptamer Microarrays (Small Molecules Detection from Split-Aptamers)

    PubMed Central

    Melaine, Feriel; Roupioz, Yoann; Buhot, Arnaud

    2015-01-01

    The detection of small molecules by biosensors remains a challenge for diagnostics in many areas like pharmacology, environment or homeland security. The main difficulty comes from both the low molecular weight and low concentrations of most targets, which generally requires an indirect detection with an amplification or a sandwich procedure. In this study, we combine both strategies as the amplification of Surface Plasmon Resonance imaging (SPRi) signal is obtained by the use of gold nanoparticles and the sequence engineering of split-aptamers, short oligonucleotides strands with strong affinity towards small targets, allows for a sandwich structure. Combining those two strategies, we obtained state-of-the-art results in the limit of detection (LOD = 50 nM) with the model target adenosine. Furthermore, the SPRi detection led on aptamer microarrays paves the way for potential multi-target detections thanks to the multi-probe imaging approach.

  17. β-Amyloid amorphous aggregates induced by the small natural molecule ferulic acid.

    PubMed

    Bramanti, Emilia; Fulgentini, Lorenzo; Bizzarri, Ranieri; Lenci, Francesco; Sgarbossa, Antonella

    2013-11-01

    There is an emerging interest in small natural molecules for their potential therapeutic use in neurodegenerative disorders like Alzheimer's disease (AD). Ferulic acid (FA), an antioxidant phenolic compound present in fruit and vegetables, has been proposed as an inhibitor of beta amyloid (Aβ) pathological aggregation. Using fluorescence and Fourier transform infrared spectroscopy, electrophoresis techniques, chromatographic analysis, and confocal microscopy, we investigated the effects of FA in the early stages of Aβ fibrillogenesis in vitro. Our results show that FA interacts promptly with Aβ monomers/oligomers, interfering since the beginning with its self-assembly and finally forming amorphous aggregates more prone to destabilization. These findings highlight the molecular basis underlying FA antiamyloidogenic activity in AD. PMID:24168390

  18. Ionization-site effects on the photofragmentation of chloro- and bromoacetic acid molecules

    NASA Astrophysics Data System (ADS)

    Levola, Helena; Itälä, Eero; Schlesier, Kim; Kooser, Kuno; Laine, Sanna; Laksman, Joakim; Ha, Dang Trinh; Rachlew, Elisabeth; Tarkanovskaja, Marta; Tanzer, Katrin; Kukk, Edwin

    2015-12-01

    Fragmentation of gas-phase chloro- and bromoacetic acid samples, particularly its dependency on the atomic site of the initial core ionization, was studied in photoelectron-photoion-photoion coincidence (PEPIPICO) measurements. The fragmentation was investigated after ionizing carbon 1 s and bromine 3 d or chlorine 2 p core orbitals. It was observed that the samples had many similar fragmentation pathways and that their relative weights depended strongly on the initial ionization site. Additional Auger PEPIPICO measurements revealed a clear dependence of fragment pair intensities on the kinetic energy of the emitted Auger electrons. The modeled and measured Auger electron spectra indicated that the average internal energy of the molecule was larger following the carbon 1 s core-hole decay than after the decay of the halogen core hole. This difference in the internal energies was found to be the source of the site-dependent photofragmentation behavior.

  19. Structural and vibrational spectroscopy investigation of the 5-[(diphenyl) amino] isophthalic acid molecule

    NASA Astrophysics Data System (ADS)

    Kurt, M.; Şaş, E. Babur; Can, M.; Okur, S.; Icli, S.; Demic, S.

    2014-10-01

    The molecular structure and vibrations of 5-(diphenyl) amino] isophthalic acid (DPIFA) were investigated by different spectroscopic techniques (such as infrared and Raman). FT-IR, FT-Raman and dispersive Raman spectra were recorded in the solid phase. HOMO-LUMO analyses were performed. The theoretical calculations for the molecular structure and spectroscopic studies were performed with DFT (B3LYP) and 6-311G(d,p) basis set calculations using the Gaussian 09 program. After optimizing the geometry of the molecule, vibration wavenumbers and fundamental vibrations wavenumbers were assigned on the basis of the potential energy distribution (PED) of the vibrational modes calculated with VEDA 4 program. The results of theoretical calculations for the spectra of the title compound were compared with the observed spectra.

  20. Mucosal targeting of therapeutic molecules using genetically modified lactic acid bacteria: an update.

    PubMed

    LeBlanc, Jean Guy; Aubry, Camille; Cortes-Perez, Naima G; de Moreno de LeBlanc, Alejandra; Vergnolle, Nathalie; Langella, Philippe; Azevedo, Vasco; Chatel, Jean-Marc; Miyoshi, Anderson; Bermúdez-Humarán, Luis G

    2013-07-01

    Lactic acid bacteria (LAB) represent a heterogeneous group of microorganisms naturally present in many foods and those have proved to be effective mucosal delivery vectors. Moreover, some specific strains of LAB exert beneficial properties (known as probiotic effect) on both human and animal health. Although probiotic effects are strain-specific traits, it is theoretically possible, using genetic engineering techniques, to design strains that can exert a variety of beneficial properties. During the two past decades, a large variety of therapeutic molecules has been successfully expressed in LAB, and although this field has been largely reviewed in recent years, approximately 20 new publications appear each year. Thus, the aim of this minireview is not to extensively assess the entire literature but to update progress made within the last 2 years regarding the use of the model LAB Lactococcus lactis and certain species of lactobacilli as live recombinant vectors for the development of new safe mucosal vaccines. PMID:23600579

  1. Acyl-coenzyme A binding domain containing 3 (ACBD3; PAP7; GCP60): an emerging signaling molecule

    PubMed Central

    Fan, Jinjiang; Liu, Jun; Culty, Martine; Papadopoulos, Vassilios

    2010-01-01

    Golgi body-mediated signaling has been linked to its fragmentation and regeneration during the mitotic cycle of the cell. During this process, Golgi-resident proteins are released to the cytosol and interact with other signaling molecules to regulate various cellular processes. Acyl-coenzyme A binding domain containing 3 protein (ACBD3) is a Golgi protein involved in several signaling events. ACBD3 protein was previously known as peripheral-type benzodiazepine receptor and cAMP-dependent protein kinase associated protein 7 (PAP7), Golgi complex-associated protein of 60 kDa (GCP60), Golgi complex-associated protein 1 (GOCAP1), and Golgi phosphoprotein 1 (GOLPH1). In this review, we present the gene ontology of ACBD3, its relations to other Acyl-coenzyme A binding protein (ACBP) domain containing proteins, and its biological function in steroidogenesis, apoptosis, neurogenesis, and embryogenesis. We also discuss the role of ACBD3 in asymmetric cell division and cancer. New findings about ACBD3 may help understand this newly characterized signaling molecule and stimulate further research into its role in molecular endocrinology, neurology, and stem cell biology. PMID:20043945

  2. Cross-Linking Poly(lactic acid) Film Surface by Neutral Hyperthermal Hydrogen Molecule Bombardment.

    PubMed

    Du, Wangli; Shao, Hong; He, Zhoukun; Tang, Changyu; Liu, Yu; Shen, Tao; Zhu, Yan; Lau, Woon-ming; Hui, David

    2015-12-16

    Constructing a dense cross-linking layer on a polymer film surface is a good way to improve the water resistance of poly(lactic acid) (PLA). However, conventional plasma treatments have failed to achieve the aim as a result of the unavoidable surface damage arising from the charged species caused by the uncontrolled high energy coming from colliding ions and electrons. In this work, we report a modified plasma method called hyperthermal hydrogen-induced cross-linking (HHIC) technology to construct a dense cross-linking layer on PLA film surfaces. This method produces energy-controlled neutral hyperthermal hydrogen, which selectively cleaves C-H bonds by molecule collision from the PLA film without breaking other bonds (e.g., C-C bonds in the polymer backbone), and results in subsequent cross-linking of the carbon radicals generated from the organic molecules. The formation of a dense cross-linking layer can serve as a barrier layer to significantly improve both the hydrophobicity and water vapor barrier property of the PLA film. Because of the advantage of selective cleavage of C-H bonds by HHIC treatment, the original physical properties (e.g., mechanical strength and light transmittance) of the PLA films are well-preserved. PMID:26594874

  3. Intramolecular cyclization of aspartic acid residues assisted by three water molecules: a density functional theory study

    NASA Astrophysics Data System (ADS)

    Takahashi, Ohgi; Kirikoshi, Ryota

    2014-01-01

    Aspartic acid (Asp) residues in peptides and proteins (l-Asp) are known to undergo spontaneous nonenzymatic reactions to form l-β-Asp, d-Asp, and d-β-Asp residues. The formation of these abnormal Asp residues in proteins may affect their three-dimensional structures and hence their properties and functions. Indeed, the reactions have been thought to contribute to aging and pathologies. Most of the above reactions of the l-Asp residues proceed via a cyclic succinimide intermediate. In this paper, a novel three-water-assisted mechanism is proposed for cyclization of an Asp residue (forming a gem-diol precursor of the succinimide) by the B3LYP/6-31 + G(d,p) density functional theory calculations carried out for an Asp-containing model compound (Ace-Asp-Nme, where Ace = acetyl and Nme = NHCH3). The three water molecules act as catalysts by mediating ‘long-range’ proton transfers. In the proposed mechanism, the amide group on the C-terminal side of the Asp residue is first converted to the tautomeric iminol form (iminolization). Then, reorientation of a water molecule and a conformational change occur successively, followed by the nucleophilic attack of the iminol nitrogen on the carboxyl carbon of the Asp side chain to form the gem-diol species. A satisfactory agreement was obtained between the calculated and experimental energetics.

  4. Role of Ethylene and Its Cross Talk with Other Signaling Molecules in Plant Responses to Heavy Metal Stress1

    PubMed Central

    Thao, Nguyen Phuong; Khan, M. Iqbal R.; Thu, Nguyen Binh Anh; Hoang, Xuan Lan Thi; Asgher, Mohd; Khan, Nafees A.; Tran, Lam-Son Phan

    2015-01-01

    Excessive heavy metals (HMs) in agricultural lands cause toxicities to plants, resulting in declines in crop productivity. Recent advances in ethylene biology research have established that ethylene is not only responsible for many important physiological activities in plants but also plays a pivotal role in HM stress tolerance. The manipulation of ethylene in plants to cope with HM stress through various approaches targeting either ethylene biosynthesis or the ethylene signaling pathway has brought promising outcomes. This review covers ethylene production and signal transduction in plant responses to HM stress, cross talk between ethylene and other signaling molecules under adverse HM stress conditions, and approaches to modify ethylene action to improve HM tolerance. From our current understanding about ethylene and its regulatory activities, it is believed that the optimization of endogenous ethylene levels in plants under HM stress would pave the way for developing transgenic crops with improved HM tolerance. PMID:26246451

  5. Gambogic acid causes fin developmental defect in zebrafish embryo partially via retinoic acid signaling.

    PubMed

    Jiang, Ling-Ling; Li, Kang; Lin, Qing-Hua; Ren, Jian; He, Zhi-Heng; Li, Huan; Shen, Ning; Wei, Ping; Feng, Feng; He, Ming-Fang

    2016-08-01

    Gambogic acid (GA), the major active ingredient of gamboge, has been approved by the Chinese Food and Drug Administration for clinical trials in cancer patients due to its strong anticancer activity. However, our previous research showed that GA was teratogenic against zebrafish fin development. To explore the teratogenicity and the underlying mechanisms, zebrafish (Danio rerio) embryos were used. The morphological observations revealed that GA caused fin defects in zebrafish embryos in a concentration-dependent manner. The critical exposure time of GA to reveal teratogenicity was before 8 hpf (hours post fertilization). LC/MS/MS analysis revealed that a maximum bioconcentration of GA was occurred at 4 hpf. Q-PCR data showed that GA treatment resulted in significant inactivation of RA signaling which could be partially rescued by the exogenous supply of RA. These results indicate the potential teratogenicity of GA and provide evidence for a caution in its future clinic use. PMID:27288890

  6. Enhancement of arachidonic acid signaling pathway by nicotinic acid receptor HM74A

    SciTech Connect

    Tang, Yuting . E-mail: ytang@prdus.jnj.com; Zhou, Lubing; Gunnet, Joseph W.; Wines, Pamela G.; Cryan, Ellen V.; Demarest, Keith T.

    2006-06-23

    HM74A is a G protein-coupled receptor for nicotinic acid (niacin), which has been used clinically to treat dyslipidemia for decades. The molecular mechanisms whereby niacin exerts its pleiotropic effects on lipid metabolism remain largely unknown. In addition, the most common side effect in niacin therapy is skin flushing that is caused by prostaglandin release, suggesting that the phospholipase A{sub 2} (PLA{sub 2})/arachidonic acid (AA) pathway is involved. Various eicosanoids have been shown to activate peroxisome-proliferator activated receptors (PPAR) that play a diverse array of roles in lipid metabolism. To further elucidate the potential roles of HM74A in mediating the therapeutic effects and/or side effects of niacin, we sought to explore the signaling events upon HM74A activation. Here we demonstrated that HM74A synergistically enhanced UTP- and bradykinin-mediated AA release in a pertussis toxin-sensitive manner in A431 cells. Activation of HM74A also led to Ca{sup 2+}-mobilization and enhanced bradykinin-promoted Ca{sup 2+}-mobilization through Gi protein. While HM74A increased ERK1/2 activation by the bradykinin receptor, it had no effects on UTP-promoted ERK1/2 activation.Furthermore, UTP- and bradykinin-mediated AA release was significantly decreased in the presence of both MAPK kinase inhibitor PD 098059 and PKC inhibitor GF 109203X. However, the synergistic effects of HM74A were not dramatically affected by co-treatment with both inhibitors, indicating the cross-talk occurred at the receptor level. Finally, stimulation of A431 cells transiently transfected with PPRE-luciferase with AA significantly induced luciferase activity, mimicking the effects of PPAR{gamma} agonist rosiglitazone, suggesting that alteration of AA signaling pathway can regulate gene expression via endogenous PPARs.

  7. Amino acid conjugated self assembling molecules for enhancing surface wettability of fiber laser treated titanium surfaces

    NASA Astrophysics Data System (ADS)

    Akkan, Cagri K.; Hür, Deniz; Uzun, Lokman; Garipcan, Bora

    2016-03-01

    Surface wetting properties of implants are one of the most critical parameter, which determine the interaction of proteins and cells with the implant surface. In this regards, acid etching and sand blasting are the mostly used methods at surface modification of Titanium (Ti) for enhanced surface wettability. Besides, these kinds of modifications may cause a conflict whether the surface wettability is influenced by the process related surface contaminations or by the surface roughness. In contrast, lasers might be an option for the alteration of surface wetting properties via supporting micro and/or nano surface topographies while preventing surface chemical contaminations. In this work, we focused on two steps of surface processing approaches of Ti surface: physical and chemical modifications. Herein, we hierarchically structured Ti surfaces by using microsecond modulated pulsed fiber laser. Subsequently, laser structured and non-structured Ti surfaces were further modified with novel histidine and leucine Amino Acid conjugated Self-Assembled Molecules (His1-SAMs2 and Leu3-SAMs) to alter the surface wettability by introducing biologically hydrophilic and hydrophobic groups. Modification of Ti surfaces with His-SAMs and Leu-SAMs ended up with stable wetting properties when compared to non-modified surfaces after 7 days which may enhances the cell-surface interaction.

  8. Evidence of splanchnic-brain signaling in inhibition of ingestive behavior by middle molecules.

    PubMed

    Mamoun, A H; Södersten, P; Anderstam, B; Bergström, J

    1999-02-01

    Anorexia, nausea, and vomiting are common symptoms of uremic intoxication. Fractions in the middle molecule weight range, isolated from normal urine and uremic plasma ultrafiltrate, inhibit ingestive behavior in the rat. To investigate their site of action and specificity, male rats were injected intraperitoneally, intravenously, or intracerebroventricularly with concentrated fractions of uremic plasma ultrafiltrate or normal urine (molecular weight range: 1.0 to 5.0 kD) and tested for ingestive and sexual behavior. An intraperitoneal injection of 0.5 ml of urine fraction (10:1) or 2.0 ml of uremic plasma ultrafiltrate fraction (25:1) inhibited carbohydrate intake by 76.3 and 45.9%, respectively, but an intravenous injection had no effect. However, intravenous injection of higher doses inhibited carbohydrate ingestion. An intracerebroventricular injection of 5 or 10 microl of urine (20:1) middle molecule fraction inhibited carbohydrate intake by 13.4 and 41.6%, respectively. An injection of 5 or 10 microl of uremic plasma ultrafiltrate (125:1) middle molecule fraction inhibited carbohydrate intake by 22.6 and 49.5%, respectively. Injections of the corresponding fraction from normal plasma ultrafiltrate had no effect. Injection of urine or uremic plasma ultrafiltrate middle molecule fractions did not affect the display of sexual behavior. These results suggest that middle molecule fractions from uremic plasma ultrafiltrate or normal urine act in the splanchnic region and/or brain to inhibit food intake and that the effect is specific for ingestive behavior. PMID:10215330

  9. Lysophosphatidic Acid Signaling through the Lysophosphatidic Acid-1 Receptor Is Required for Alveolarization.

    PubMed

    Funke, Manuela; Knudsen, Lars; Lagares, David; Ebener, Simone; Probst, Clemens K; Fontaine, Benjamin A; Franklin, Alicia; Kellner, Manuela; Kühnel, Mark; Matthieu, Stephanie; Grothausmann, Roman; Chun, Jerold; Roberts, Jesse D; Ochs, Matthias; Tager, Andrew M

    2016-07-01

    Lysophosphatidic acid (LPA) signaling through one of its receptors, LPA1, contributes to both the development and the pathological remodeling after injury of many organs. Because we found previously that LPA-LPA1 signaling contributes to pulmonary fibrosis, here we investigated whether this pathway is also involved in lung development. Quantitative assessment of lung architecture of LPA1-deficient knock-out (KO) and wild-type (WT) mice at 3, 12, and 24 weeks of age using design-based stereology suggested the presence of an alveolarization defect in LPA1 KO mice at 3 weeks, which persisted as alveolar numbers increased in WT mice into adulthood. Across the ages examined, the lungs of LPA1 KO mice exhibited decreased alveolar numbers, septal tissue volumes, and surface areas, and increased volumes of the distal airspaces. Elastic fibers, critical to the development of alveolar septa, appeared less organized and condensed and more discontinuous in KO alveoli starting at P4. Tropoelastin messenger RNA expression was decreased in KO lungs, whereas expression of matrix metalloproteinases degrading elastic fibers was either decreased or unchanged. These results are consistent with the abnormal lung phenotype of LPA1 KO mice, being attributable to reduced alveolar septal formation during development, rather than to increased septal destruction as occurs in the emphysema of chronic obstructive pulmonary disease. Peripheral septal fibroblasts and myofibroblasts, which direct septation in late alveolarization, demonstrated reduced production of tropoelastin and matrix metalloproteinases, and diminished LPA-induced migration, when isolated from LPA1 KO mice. Taken together, our data suggest that LPA-LPA1 signaling is critically required for septation during alveolarization. PMID:27082727

  10. Association between cytoplasmic CRABP2, altered retinoic acid signaling, and poor prognosis in glioblastoma.

    PubMed

    Liu, Rong-Zong; Li, Shuai; Garcia, Elizabeth; Glubrecht, Darryl D; Yin Poon, Ho; Easaw, Jacob C; Godbout, Roseline

    2016-06-01

    Retinoic acid (RA), a metabolite of vitamin A, is required for the regulation of growth and development. Aberrant expression of molecules involved in RA signaling has been reported in various cancer types including glioblastoma multiforme (GBM). Cellular retinoic acid-binding protein 2 (CRABP2) has previously been shown to play a key role in the transport of RA to retinoic acid receptors (RARs) to activate their transcription regulatory activity. Here, we demonstrate that CRABP2 is predominantly located in the cytoplasm of GBM tumors. Cytoplasmic, but not nuclear, CRABP2 levels in GBM tumors are associated with poor patient survival. Treatment of malignant glioma cell lines with RA results in a dose-dependent increase in accumulation of CRABP2 in the cytoplasm. CRABP2 knockdown reduces proliferation rates of malignant glioma cells, and enhances RA-induced RAR activation. Levels of CRYAB, a small heat shock protein with anti-apoptotic activity, and GFAP, an astrocyte-specific intermediate filament protein, are greatly reduced in CRABP2-depleted cells. Restoration of CRYAB expression partially but significantly reversed the effect of CRABP2 depletion on RAR activation. Our combined in vivo and in vitro data indicate that: (i) CRABP2 is an important determinant of clinical outcome in GBM patients, and (ii) the mechanism of action of CRABP2 in GBM involves sequestration of RA in the cytoplasm and activation of an anti-apoptotic pathway, thereby enhancing proliferation and preventing RA-mediated cell death and differentiation. We propose that reducing CRABP2 levels may enhance the therapeutic index of RA in GBM patients. GLIA 2016;64:963-976. PMID:26893190

  11. Inhibition of TLR2 signaling by small molecule inhibitors targeting a pocket within the TLR2 TIR domain.

    PubMed

    Mistry, Pragnesh; Laird, Michelle H W; Schwarz, Ryan S; Greene, Shannon; Dyson, Tristan; Snyder, Greg A; Xiao, Tsan Sam; Chauhan, Jay; Fletcher, Steven; Toshchakov, Vladimir Y; MacKerell, Alexander D; Vogel, Stefanie N

    2015-04-28

    Toll-like receptor (TLR) signaling is initiated by dimerization of intracellular Toll/IL-1 receptor resistance (TIR) domains. For all TLRs except TLR3, recruitment of the adapter, myeloid differentiation primary response gene 88 (MyD88), to TLR TIR domains results in downstream signaling culminating in proinflammatory cytokine production. Therefore, blocking TLR TIR dimerization may ameliorate TLR2-mediated hyperinflammatory states. The BB loop within the TLR TIR domain is critical for mediating certain protein-protein interactions. Examination of the human TLR2 TIR domain crystal structure revealed a pocket adjacent to the highly conserved P681 and G682 BB loop residues. Using computer-aided drug design (CADD), we sought to identify a small molecule inhibitor(s) that would fit within this pocket and potentially disrupt TLR2 signaling. In silico screening identified 149 compounds and 20 US Food and Drug Administration-approved drugs based on their predicted ability to bind in the BB loop pocket. These compounds were screened in HEK293T-TLR2 transfectants for the ability to inhibit TLR2-mediated IL-8 mRNA. C16H15NO4 (C29) was identified as a potential TLR2 inhibitor. C29, and its derivative, ortho-vanillin (o-vanillin), inhibited TLR2/1 and TLR2/6 signaling induced by synthetic and bacterial TLR2 agonists in human HEK-TLR2 and THP-1 cells, but only TLR2/1 signaling in murine macrophages. C29 failed to inhibit signaling induced by other TLR agonists and TNF-α. Mutagenesis of BB loop pocket residues revealed an indispensable role for TLR2/1, but not TLR2/6, signaling, suggesting divergent roles. Mice treated with o-vanillin exhibited reduced TLR2-induced inflammation. Our data provide proof of principle that targeting the BB loop pocket is an effective approach for identification of TLR2 signaling inhibitors. PMID:25870276

  12. Transport and signaling via the amino acid binding site of the yeast Gap1 amino acid transceptor.

    PubMed

    Van Zeebroeck, Griet; Bonini, Beatriz Monge; Versele, Matthias; Thevelein, Johan M

    2009-01-01

    Transporter-related nutrient sensors, called transceptors, mediate nutrient activation of signaling pathways through the plasma membrane. The mechanism of action of transporting and nontransporting transceptors is unknown. We have screened 319 amino acid analogs to identify compounds that act on Gap1, a transporting amino acid transceptor in yeast that triggers activation of the protein kinase A pathway. We identified competitive and noncompetitive inhibitors of transport, either with or without agonist action for signaling, including nontransported agonists. Using substituted cysteine accessibility method (SCAM) analysis, we identified Ser388 and Val389 as being exposed into the amino acid binding site, and we show that agonist action for signaling uses the same binding site as used for transport. Our results provide the first insight, to our knowledge, into the mechanism of action of transceptors. They indicate that signaling requires a ligand-induced specific conformational change that may be part of but does not require the complete transport cycle. PMID:19060912

  13. Identification of a Small Molecule Signaling Factor That Regulates the Biosynthesis of the Antifungal Polycyclic Tetramate Macrolactam HSAF in Lysobacter enzymogenes

    PubMed Central

    Han, Yong; Wang, Yan; Tombosa, Simon; Wright, Stephen; Huffman, Justin; Yuen, Gary; Qian, Guoliang; Liu, Fengquan; Shen, Yuemao; Du, Liangcheng

    2014-01-01

    Lysobacter species are emerging as new sources of antibiotics. The regulation of these antibiotics is not well understood. Here, we identified a small molecule metabolite (LeDSF3) that regulates the biosynthesis of the antifungal antibiotic HSAF (heat-stable antifungal factor), a polycyclic tetramate macrolactam with a structure and mode of action distinct from the existing antifungal drugs. LeDSF3 was isolated from the culture broth of L. enzymogenes, and its chemical structure was established by NMR and MS. The purified compound induced green fluorescence in a reporter strain of Xanthomonas campestris, which contained gfp gene under the control of a DSF (diffusible signaling factor)-inducible promoter. Exogenous addition of LeDSF3 in L. enzymogenes cultures significantly increased the HSAF yield, the transcription of HSAF biosynthetic genes, and the antifungal activity of the organism. The LeDSF3-regulated HSAF production is dependent on the two-component regulatory system RpfC/RpfG. Moreover, LeDSF3 up-regulated the expression of the global regulator Clp (cAMP receptor-like protein). The disruption of clp led to no HSAF production. Together, the results show that LeDSF3 is a fatty acid-derived, diffusible signaling factor positively regulating HSAF biosynthesis and that the signaling is mediated by the RfpC/RpfG-Clp pathway. These findings may facilitate the antibiotic production through applied genetics and molecular biotechnology in Lysobacter, a group of ubiquitous yet underexplored microorganisms. PMID:25301587

  14. Ceramides and cell signaling molecules in psoriatic epidermis: reduced levels of ceramides, PKC-alpha, and JNK.

    PubMed

    Lew, Bark-Lynn; Cho, Yunhi; Kim, Jungmin; Sim, Woo-Young; Kim, Nack-In

    2006-02-01

    Ceramides are the main lipids in the stratum corneum and are generated during cellular stress and apoptosis by de novo synthesis or by the action of sphingomyelinase. In addition, they are lipid second messengers produced by sphingolipid metabolism and trigger important cell responses, including protein kinase C-alpha (PKC-alpha) activation and the stimulation of signal transduction pathways with apoptosis and stress-activated protein kinases (SAPK), such as c-jun N-terminal kinase (JNK). Thus, ceramides have anti-proliferative and apoptotic effects. This study measured the changes in the levels of epidermal ceramides and ceramide-related apoptotic signaling molecules in psoriasis patients. Samples from lesional and non-lesional epidermis were obtained from psoriasis patients. Total ceramides were fractionated using thin-layer chromatography, and the levels of PKC-alpha and JNK expression were measured using Western blot analysis with specific antibodies. The ceramide level was reduced significantly, and this was associated with the downregulation of apoptotic signaling molecules, such as PKC-alpha and JNK, in the lesional epidermis of psoriasis patients. These results suggest that the decreased level of ceramides downregulates the apoptotic pathway, leading to epidermal proliferation in psoriasis. PMID:16479073

  15. Cardiac-Specific SOCS3 Deletion Prevents In Vivo Myocardial Ischemia Reperfusion Injury through Sustained Activation of Cardioprotective Signaling Molecules

    PubMed Central

    Nagata, Takanobu; Yasukawa, Hideo; Kyogoku, Sachiko; Oba, Toyoharu; Takahashi, Jinya; Nohara, Shoichiro; Minami, Tomoko; Mawatari, Kazutoshi; Sugi, Yusuke; Shimozono, Koutatsu; Pradervand, Sylvain; Hoshijima, Masahiko; Aoki, Hiroki; Fukumoto, Yoshihiro; Imaizumi, Tsutomu

    2015-01-01

    Myocardial ischemia reperfusion injury (IRI) adversely affects cardiac performance and the prognosis of patients with acute myocardial infarction. Although myocardial signal transducer and activator of transcription (STAT) 3 is potently cardioprotective during IRI, the inhibitory mechanism responsible for its activation is largely unknown. The present study aimed to investigate the role of the myocardial suppressor of cytokine signaling (SOCS)-3, an intrinsic negative feedback regulator of the Janus kinase (JAK)-STAT signaling pathway, in the development of myocardial IRI. Myocardial IRI was induced in mice by ligating the left anterior descending coronary artery for 1 h, followed by different reperfusion times. One hour after reperfusion, the rapid expression of JAK-STAT–activating cytokines was observed. We precisely evaluated the phosphorylation of cardioprotective signaling molecules and the expression of SOCS3 during IRI and then induced myocardial IRI in wild-type and cardiac-specific SOCS3 knockout mice (SOCS3-CKO). The activation of STAT3, AKT, and ERK1/2 rapidly peaked and promptly decreased during IRI. This decrease correlated with the induction of SOCS3 expression up to 24 h after IRI in wild-type mice. The infarct size 24 h after reperfusion was significantly reduced in SOCS3-CKO compared with wild-type mice. In SOCS3-CKO mice, STAT3, AKT, and ERK1/2 phosphorylation was sustained, myocardial apoptosis was prevented, and the expression of anti-apoptotic Bcl-2 family member myeloid cell leukemia-1 (Mcl-1) was augmented. Cardiac-specific SOCS3 deletion led to the sustained activation of cardioprotective signaling molecules including and prevented myocardial apoptosis and injury during IRI. Our findings suggest that SOCS3 may represent a key factor that exacerbates the development of myocardial IRI. PMID:26010537

  16. Chlorogenic Acid Improves Late Diabetes through Adiponectin Receptor Signaling Pathways in db/db Mice

    PubMed Central

    Jin, Shasha; Chang, Cuiqing; Zhang, Lantao; Liu, Yang; Huang, Xianren; Chen, Zhimin

    2015-01-01

    The aim of this study was to examine the effects of chlorogenic acid (CGA) on glucose and lipid metabolism in late diabetic db/db mice, as well as on adiponectin receptors and their signaling molecules, to provide evidence for CGA in the prevention of type 2 diabetes. We randomly divided 16 female db/db mice into db/db-CGA and db/db-control (CON) groups equally; db/m mice were used as control mice. The mice in both the db/db-CGA and db/m-CGA groups were administered 80 mg/kg/d CGA by lavage for 12 weeks, whereas the mice in both CON groups were given equal volumes of phosphate-buffered saline (PBS) by lavage. At the end of the intervention, we assessed body fat and the parameters of glucose and lipid metabolism in the plasma, liver and skeletal muscle tissues as well as the levels of aldose reductase (AR) and transforming growth factor-β1 (TGF-β1) in the kidneys and measured adiponectin receptors and the protein expression of their signaling molecules in liver and muscle tissues. After 12 weeks of intervention, compared with the db/db-CON group, the percentage of body fat, fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA1c) in the db/db-CGA group were all significantly decreased; TGF-β1 protein expression and AR activity in the kidney were both decreased; and the adiponectin level in visceral adipose was increased. The protein expression of adiponectin receptors (ADPNRs), the phosphorylation of AMP-activated protein kinase (AMPK) in the liver and muscle, and the mRNA and protein levels of peroxisome proliferator-activated receptor alpha (PPAR-α) in the liver were all significantly greater. CGA could lower the levels of fasting plasma glucose and HbA1c during late diabetes and improve kidney fibrosis to some extent through the modulation of adiponectin receptor signaling pathways in db/db mice. PMID:25849026

  17. The neural adhesion molecule TAG-1 modulates responses of sensory axons to diffusible guidance signals.

    PubMed

    Law, Chris O; Kirby, Rebecca J; Aghamohammadzadeh, Soheil; Furley, Andrew J W

    2008-08-01

    When the axons of primary sensory neurons project into the embryonic mammalian spinal cord, they bifurcate and extend rostrocaudally before sending collaterals to specific laminae according to neuronal subclass. The specificity of this innervation has been suggested to be the result both of differential sensitivity to chemorepellants expressed in the ventral spinal cord and of the function of Ig-like neural cell adhesion molecules in the dorsal horn. The relationship between these mechanisms has not been addressed. Focussing on the pathfinding of TrkA+ NGF-dependent axons, we demonstrate for the first time that their axons project prematurely into the dorsal horn of both L1 and TAG-1 knockout mice. We show that axons lacking TAG-1, similar to those lacking L1, are insensitive to wild-type ventral spinal cord (VSC)-derived chemorepellants, indicating that adhesion molecule function is required in the axons, and that this loss of response is explained in part by loss of response to Sema3A. We present evidence that TAG-1 affects sensitivity to Sema3A by binding to L1 and modulating the endocytosis of the L1/neuropilin 1 Sema3A receptor complex. However, TAG-1 appears to affect sensitivity to other VSC-derived chemorepellants via an L1-independent mechanism. We suggest that this dependence of chemorepellant sensitivity on the functions of combinations of adhesion molecules is important to ensure that axons project via specific pathways before extending to their final targets. PMID:18550718

  18. Degradation of the Plant Defense Signal Salicylic Acid Protects Ralstonia solanacearum from Toxicity and Enhances Virulence on Tobacco

    PubMed Central

    Lowe-Power, Tiffany M.; Jacobs, Jonathan M.; Ailloud, Florent; Fochs, Brianna; Prior, Philippe

    2016-01-01

    ABSTRACT Plants use the signaling molecule salicylic acid (SA) to trigger defenses against diverse pathogens, including the bacterial wilt pathogen Ralstonia solanacearum. SA can also inhibit microbial growth. Most sequenced strains of the heterogeneous R. solanacearum species complex can degrade SA via gentisic acid to pyruvate and fumarate. R. solanacearum strain GMI1000 expresses this SA degradation pathway during tomato pathogenesis. Transcriptional analysis revealed that subinhibitory SA levels induced expression of the SA degradation pathway, toxin efflux pumps, and some general stress responses. Interestingly, SA treatment repressed expression of virulence factors, including the type III secretion system, suggesting that this pathogen may suppress virulence functions when stressed. A GMI1000 mutant lacking SA degradation activity was much more susceptible to SA toxicity but retained the wild-type colonization ability and virulence on tomato. This may be because SA is less important than gentisic acid in tomato defense signaling. However, another host, tobacco, responds strongly to SA. To test the hypothesis that SA degradation contributes to virulence on tobacco, we measured the effect of adding this pathway to the tobacco-pathogenic R. solanacearum strain K60, which lacks SA degradation genes. Ectopic addition of the GMI1000 SA degradation locus, including adjacent genes encoding two porins and a LysR-type transcriptional regulator, significantly increased the virulence of strain K60 on tobacco. Together, these results suggest that R. solanacearum degrades plant SA to protect itself from inhibitory levels of this compound and also to enhance its virulence on plant hosts like tobacco that use SA as a defense signal molecule. PMID:27329752

  19. Retinoic acid affects calcium signaling in adult molluscan neurons.

    PubMed

    Vesprini, Nicholas D; Dawson, Taylor F; Yuan, Ye; Bruce, Doug; Spencer, Gaynor E

    2015-01-01

    Retinoic acid, the active metabolite of vitamin A, is important for nervous system development, regeneration, as well as cognitive functions of the adult central nervous system. These central nervous system functions are all highly dependent on neuronal activity. Retinoic acid has previously been shown to induce changes in the firing properties and action potential waveforms of adult molluscan neurons in a dose- and isomer-dependent manner. In this study, we aimed to determine the cellular pathways by which retinoic acid might exert such effects, by testing the involvement of pathways previously shown to be affected by retinoic acid. We demonstrated that the ability of all-trans retinoic acid (atRA) to induce electrophysiological changes in cultured molluscan neurons was not prevented by inhibitors of protein synthesis, protein kinase A or phospholipase C. However, we showed that atRA was capable of rapidly reducing intracellular calcium levels in the same dose- and isomer-dependent manner as shown previously for changes in neuronal firing. Moreover, we also demonstrated that the transmembrane ion flux through voltage-gated calcium channels was rapidly modulated by retinoic acid. In particular, the peak current density was reduced and the inactivation rate was increased in the presence of atRA, over a similar time course as the changes in cell firing and reductions in intracellular calcium. These studies provide further evidence for the ability of atRA to induce rapid effects in mature neurons. PMID:25343782

  20. A novel small-molecule inhibitor of NF-{kappa}B signaling

    SciTech Connect

    Nakajima, Hiroto; Fujiwara, Hideyasu; Furuichi, Yasuhiro Tanaka, Keiji Shimbara, Naoki

    2008-04-18

    The inducible transcription factor NF-{kappa}B regulates divergent signaling pathways including inflammatory response and cancer development. Selective inhibitors for NF-{kappa}B signaling are potentially useful for treatment of inflammation and cancer. NF-{kappa}B is canonically activated by preferential disposal of its inhibitory protein; I{kappa}B, which suppresses the nuclear translocation of NF-{kappa}B. I{kappa}B{alpha} (a major member of I{kappa}B family proteins) is phosphorylated with an I{kappa}B kinase (IKK) and subsequently polyubiquitylated by SCF{sup {beta}}{sup TrCP1} ubiquitin-ligase in the presence of E1 and E2 prior to proteasomal degradation. Here, we describe a novel inhibitor termed GS143, which suppressed I{kappa}B{alpha} ubiquitylation, but not I{kappa}B{alpha} phosphorylation, MDM2-directed p53 ubiquitylation, and proteasome activity in vitro. GS143 markedly suppressed the destruction of I{kappa}B{alpha} stimulated by TNF{alpha} and a set of downstream responses coupled to NF-{kappa}B signaling but not those of p53 and {beta}-catenin in vivo. Our results indicate that GS143 serves as an effective inhibitor of multiple pathways served by NF-{kappa}B signaling.

  1. TCR Microclusters pre-exist and contain molecules necessary for TCR signal transduction.

    PubMed

    Crites, Travis J; Padhan, Kartika; Muller, James; Krogsgaard, Michelle; Gudla, Prabhakar R; Lockett, Stephen J; Varma, Rajat

    2014-07-01

    TCR-dependent signaling events have been observed to occur in TCR microclusters. We found that some TCR microclusters are present in unstimulated murine T cells, indicating that the mechanisms leading to microcluster formation do not require ligand binding. These pre-existing microclusters increase in absolute number following engagement by low-potency ligands. This increase is accompanied by an increase in cell spreading, with the result that the density of TCR microclusters on the surface of the T cell is not a strong function of ligand potency. In characterizing their composition, we observed a constant number of TCRs in a microcluster, constitutive exclusion of the phosphatase CD45, and preassociation with the signaling adapters linker for activation of T cells and growth factor receptor-bound protein 2. The existence of TCR microclusters prior to ligand binding in a state that is conducive for the initiation of downstream signaling could explain, in part, the rapid kinetics with which TCR signal transduction occurs. PMID:24860189

  2. IP-FCM Measures Physiologic Protein-Protein Interactions Modulated by Signal Transduction and Small-Molecule Drug Inhibition

    PubMed Central

    Smith, Stephen E. P.; Bida, Anya T.; Davis, Tessa R.; Sicotte, Hugues; Patterson, Steven E.; Gil, Diana; Schrum, Adam G.

    2012-01-01

    Protein-protein interactions (PPI) mediate the formation of intermolecular networks that control biological signaling. For this reason, PPIs are of outstanding interest in pharmacology, as they display high specificity and may represent a vast pool of potentially druggable targets. However, the study of physiologic PPIs can be limited by conventional assays that often have large sample requirements and relatively low sensitivity. Here, we build on a novel method, immunoprecipitation detected by flow cytometry (IP-FCM), to assess PPI modulation during either signal transduction or pharmacologic inhibition by two different classes of small-molecule compounds. First, we showed that IP-FCM can detect statistically significant differences in samples possessing a defined PPI change as low as 10%. This sensitivity allowed IP-FCM to detect a PPI that increases transiently during T cell signaling, the antigen-inducible interaction between ZAP70 and the T cell antigen receptor (TCR)/CD3 complex. In contrast, IP-FCM detected no ZAP70 recruitment when T cells were stimulated with antigen in the presence of the src-family kinase inhibitor, PP2. Further, we tested whether IP-FCM possessed sufficient sensitivity to detect the effect of a second, rare class of compounds called SMIPPI (small-molecule inhibitor of PPI). We found that the first-generation non-optimized SMIPPI, Ro-26-4550, inhibited the IL-2:CD25 interaction detected by IP-FCM. This inhibition was detectable using either a recombinant CD25-Fc chimera or physiologic full-length CD25 captured from T cell lysates. Thus, we demonstrate that IP-FCM is a sensitive tool for measuring physiologic PPIs that are modulated by signal transduction and pharmacologic inhibition. PMID:23029201

  3. Wnt Signaling Orchestration with a Small Molecule DYRK Inhibitor Provides Long-Term Xeno-Free Human Pluripotent Cell Expansion

    PubMed Central

    Hasegawa, Kouichi; Yasuda, Shin-ya; Teo, Jia-Ling; Nguyen, Cu; McMillan, Michael; Hsieh, Chih-Lin; Suemori, Hirofumi; Nakatsuji, Norio; Yamamoto, Masashi; Miyabayashi, Tomoyuki; Lutzko, Carolyn; Pera, Martin F.

    2012-01-01

    An optimal culture system for human pluripotent stem cells should be fully defined and free of animal components. To date, most xeno-free culture systems require human feeder cells and/or highly complicated culture media that contain activators of the fibroblast growth factor (FGF) and transforming growth factor-β (TGFβ) signaling pathways, and none provide for replacement of FGF/TGFβ ligands with chemical compounds. The Wnt/β-catenin signaling pathway plays an important role in mouse embryonic stem cells in leukemia inhibitory factor-independent culture; however, the role of Wnt/β-catenin signaling in human pluripotent stem cell is still poorly understood and controversial because of the dual role of Wnts in proliferation and differentiation. Building on our previous investigations of small molecules modulating Wnt/β-catenin signaling in mouse embryonic stem cells, we identified a compound, ID-8, that could support Wnt-induced human embryonic stem cell proliferation and survival without differentiation. Dual-specificity tyrosine phosphorylation-regulated kinase (DYRK) is the target of the small molecule ID-8. Its role in human pluripotent cell renewal was confirmed by DYRK knockdown in human embryonic stem cells. Using Wnt and the DYRK inhibitor ID-8, we have developed a novel and simple chemically defined xeno-free culture system that allows for long-term expansion of human pluripotent stem cells without FGF or TGFβ activation. These culture conditions do not include xenobiotic supplements, serum, serum replacement, or albumin. Using this culture system, we have shown that several human pluripotent cell lines maintained pluripotency (>20 passages) and a normal karyotype and still retained the ability to differentiate into derivatives of all three germ layers. This Wnt-dependent culture system should provide a platform for complete replacement of growth factors with chemical compounds. PMID:23197636

  4. Arabidopsis INCURVATA2 Regulates Salicylic Acid and Abscisic Acid Signaling, and Oxidative Stress Responses.

    PubMed

    Micol-Ponce, Rosa; Sánchez-García, Ana Belén; Xu, Qian; Barrero, José María; Micol, José Luis; Ponce, María Rosa

    2015-11-01

    Epigenetic regulatory states can persist through mitosis and meiosis, but the connection between chromatin structure and DNA replication remains unclear. Arabidopsis INCURVATA2 (ICU2) encodes the catalytic subunit of DNA polymerase α, and null alleles of ICU2 have an embryo-lethal phenotype. Analysis of icu2-1, a hypomorphic allele of ICU2, demonstrated that ICU2 functions in chromatin-mediated cellular memory; icu2-1 strongly impairs ICU2 function in the maintenance of repressive epigenetic marks but does not seem to affect ICU2 polymerase activity. To better understand the global function of ICU2 in epigenetic regulation, here we performed a microarray analysis of icu2-1 mutant plants. We found that the genes up-regulated in the icu2-1 mutant included genes encoding transcription factors and targets of the Polycomb Repressive Complexes. The down-regulated genes included many known players in salicylic acid (SA) biosynthesis and accumulation, ABA signaling and ABA-mediated responses. In addition, we found that icu2-1 plants had reduced SA levels in normal conditions; infection by Fusarium oxysporum induced SA accumulation in the En-2 wild type but not in the icu2-1 mutant. The icu2-1 plants were also hypersensitive to salt stress and exogenous ABA in seedling establishment, post-germination growth and stomatal closure, and accumulated more ABA than the wild type in response to salt stress. The icu2-1 mutant also showed high tolerance to the oxidative stress produced by 3-amino-1,2,4-triazole (3-AT). Our results uncover a role for ICU2 in the regulation of genes involved in ABA signaling as well as in SA biosynthesis and accumulation. PMID:26423959

  5. Nucleation of Mixed Nitric Acid-Water Ice Nanoparticles in Molecular Beams that Starts with a HNO3 Molecule.

    PubMed

    Lengyel, Jozef; Pysanenko, Andriy; Kočišek, Jaroslav; Poterya, Viktoriya; Pradzynski, Christoph C; Zeuch, Thomas; Slavíček, Petr; Fárník, Michal

    2012-11-01

    Mixed (HNO3)m(H2O)n clusters generated in supersonic expansion of nitric acid vapor are investigated in two different experiments, (1) time-of-flight mass spectrometry after electron ionization and (2) Na doping and photoionization. This combination of complementary methods reveals that only clusters containing at least one acid molecule are generated, that is, the acid molecule serves as the nucleation center in the expansion. The experiments also suggest that at least four water molecules are needed for HNO3 acidic dissociation. The clusters are undoubtedly generated, as proved by electron ionization; however, they are not detected by the Na doping due to a fast charge-transfer reaction between the Na atom and HNO3. This points to limitations of the Na doping recently advocated as a general method for atmospheric aerosol detection. On the other hand, the combination of the two methods introduces a tool for detecting molecules with sizable electron affinity in clusters. PMID:26296012

  6. Small Molecule APY606 Displays Extensive Antitumor Activity in Pancreatic Cancer via Impairing Ras-MAPK Signaling.

    PubMed

    Guo, Na; Liu, Zuojia; Zhao, Wenjing; Wang, Erkang; Wang, Jin

    2016-01-01

    Pancreatic cancer has been found with abnormal expression or mutation in Ras proteins. Oncogenic Ras activation exploits their extensive signaling reach to affect multiple cellular processes, in which the mitogen-activated protein kinase (MAPK) signaling exerts important roles in tumorigenesis. Therapies targeted Ras are thus of major benefit for pancreatic cancer. Although small molecule APY606 has been successfully picked out by virtual drug screening based on Ras target receptor, its in-depth mechanism remains to be elucidated. We herein assessed the antitumor activity of APY606 against human pancreatic cancer Capan-1 and SW1990 cell lines and explored the effect of Ras-MAPK and apoptosis-related signaling pathway on the activity of APY606. APY606 treatment resulted in a dose- and time-dependent inhibition of cancer cell viability. Additionally, APY606 exhibited strong antitumor activity, as evidenced not only by reduction in tumor cell invasion, migration and mitochondrial membrane potential but also by alteration in several apoptotic indexes. Furthermore, APY606 treatment directly inhibited Ras-GTP and the downstream activation of MAPK, which resulted in the down-regulation of anti-apoptotic protein Bcl-2, leading to the up-regulation of mitochondrial apoptosis pathway-related proteins (Bax, cytosolic Cytochrome c and Caspase 3) and of cyclin-dependent kinase 2 and Cyclin A, E. These data suggest that impairing Ras-MAPK signaling is a novel mechanism of action for APY606 during therapeutic intervention in pancreatic cancer. PMID:27223122

  7. Small Molecule APY606 Displays Extensive Antitumor Activity in Pancreatic Cancer via Impairing Ras-MAPK Signaling

    PubMed Central

    Guo, Na; Liu, Zuojia; Zhao, Wenjing; Wang, Erkang; Wang, Jin

    2016-01-01

    Pancreatic cancer has been found with abnormal expression or mutation in Ras proteins. Oncogenic Ras activation exploits their extensive signaling reach to affect multiple cellular processes, in which the mitogen-activated protein kinase (MAPK) signaling exerts important roles in tumorigenesis. Therapies targeted Ras are thus of major benefit for pancreatic cancer. Although small molecule APY606 has been successfully picked out by virtual drug screening based on Ras target receptor, its in-depth mechanism remains to be elucidated. We herein assessed the antitumor activity of APY606 against human pancreatic cancer Capan-1 and SW1990 cell lines and explored the effect of Ras-MAPK and apoptosis-related signaling pathway on the activity of APY606. APY606 treatment resulted in a dose- and time-dependent inhibition of cancer cell viability. Additionally, APY606 exhibited strong antitumor activity, as evidenced not only by reduction in tumor cell invasion, migration and mitochondrial membrane potential but also by alteration in several apoptotic indexes. Furthermore, APY606 treatment directly inhibited Ras-GTP and the downstream activation of MAPK, which resulted in the down-regulation of anti-apoptotic protein Bcl-2, leading to the up-regulation of mitochondrial apoptosis pathway-related proteins (Bax, cytosolic Cytochrome c and Caspase 3) and of cyclin-dependent kinase 2 and Cyclin A, E. These data suggest that impairing Ras-MAPK signaling is a novel mechanism of action for APY606 during therapeutic intervention in pancreatic cancer. PMID:27223122

  8. Fabrication of nickel and gold nanowires by controlled electrodeposition on deoxyribonucleic acid molecules

    NASA Astrophysics Data System (ADS)

    Gu, Qun; Jin, Helena; Dai, Kun

    2009-01-01

    Magnetic and electrical nanowires are two important materials in the development of futuristic nanoelectronics, data storage media and nanosensors. Ni and Au nanowires with a diameter of a few tens of nanometres have been fabricated using deoxyribonucleic acid (DNA) molecules as a template through nanoparticle-controlled electroless deposition (ELD). Nanowire precursors, 1-3 nm Pt(0)-DNA and 1.4 nm Au(0)-DNA, were assembled using two different methods. Chemical reduction was used to deposit Pt(0) particles on DNA which catalyzed Ni nanowire growth. Positively charged Au nanoparticles were directly assembled on phosphate groups of DNA which were stretched and anchored between micrometre-spaced electrodes. Electrical measurement has shown that Au nanowires, catalyzed by Au(0)-DNA in a subsequent ELD, are highly conductive and show linear I-V characteristics. The major factors for the resistivity of nanowires were discussed in detail. This work involves important aspects in the field of DNA-based self-assembly, such as DNA and surface interaction, DNA nanoparticle assembly and electrical property of fabricated nanowires.

  9. Relationship between ST8SIA2, polysialic acid and its binding molecules, and psychiatric disorders.

    PubMed

    Sato, Chihiro; Hane, Masaya; Kitajima, Ken

    2016-08-01

    Polysialic acid (polySia, PSA) is a unique and functionally important glycan, particularly in vertebrate brains. It is involved in higher brain functions such as learning, memory, and social behaviors. Recently, an association between several genetic variations and single nucleotide polymorphisms (SNPs) of ST8SIA2/STX, one of two polysialyltransferase genes in vertebrates, and psychiatric disorders, such as schizophrenia (SZ), bipolar disorder (BD), and autism spectrum disorder (ASD), was reported based on candidate gene approaches and genome-wide studies among normal and mental disorder patients. It is of critical importance to determine if the reported mutations and SNPs in ST8SIA2 lead to impairments of the structure and function of polySia, which is the final product of ST8SIA2. To date, however, only a few such forward-directed studies have been conducted. In addition, the molecular mechanisms underlying polySia-involved brain functions remain unknown, although polySia was shown to have an anti-adhesive effect. In this report, we review the relationships between psychiatric disorders and polySia and/or ST8SIA2, and describe a new function of polySia as a regulator of neurologically active molecules, such as brain-derived neurotrophic factor (BDNF) and dopamine, which are deeply involved in psychiatric disorders. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc. PMID:27105834

  10. Purification of an Extracellular Signaling Molecule Involved in Production of Aerial Mycelium by Streptomyces coelicolor

    PubMed Central

    Nodwell, Justin R.; Losick, Richard

    1998-01-01

    We have extensively purified a factor from conditioned medium that restores aerial mycelium formation to a mutant of Streptomyces coelicolor that is defective in morphological differentiation. Response to this factor is shown to depend on the presence of the BldK oligopeptide import system. We suggest that this substance acts at the first step in a putative cascade of developmental regulatory signals. PMID:9495776

  11. Nuclear receptor-dependent bile acid signaling is required for normal liver regeneration.

    PubMed

    Huang, Wendong; Ma, Ke; Zhang, Jun; Qatanani, Mohammed; Cuvillier, James; Liu, Jun; Dong, Bingning; Huang, Xiongfei; Moore, David D

    2006-04-14

    Liver mass depends on one or more unidentified humoral signals that drive regeneration when liver functional capacity is diminished. Bile acids are important liver products, and their levels are tightly regulated. Here, we identify a role for nuclear receptor-dependent bile acid signaling in normal liver regeneration. Elevated bile acid levels accelerate regeneration, and decreased levels inhibit liver regrowth, as does the absence of the primary nuclear bile acid receptor FXR. We propose that FXR activation by increased bile acid flux is a signal of decreased functional capacity of the liver. FXR, and possibly other nuclear receptors, may promote homeostasis not only by regulating expression of appropriate metabolic target genes but also by driving homeotrophic liver growth. PMID:16614213

  12. Production of N-acylhomoserine lactone signal molecules by gram-negative soil-borne and plant-associated bacteria.

    PubMed

    Veselova, M; Kholmeckaya, M; Klein, S; Voronina, E; Lipasova, V; Metlitskaya, A; Mayatskaya, A; Lobanok, E; Khmel, I; Chernin, L

    2003-01-01

    Quorum-sensing control mediated by N-acylhomoserine lactone (AHL) signal molecules has been established as a key feature in the regulation of various metabolic traits in many bacteria. Approximately 300 strains representing 6 genera and 18 species of soil-borne and plant-associated Gram-negative bacteria isolated in various regions of the former USSR using two reporter systems were screened for AHL production. The production was observed in 17.5% of the screened bacterial strains. Positive response was detected in all of the 14 tested strains of Erwinia herbicola, in 41 of the 239 strains of Pseudomonas species; in all 5 strains of Xanthomonas ampelina, X. campestris pv. malvacearum, pv. translucens, pv. vesicatoria and in one strain of Pantoea stewartii. AHL assay of 41 strains of X. maltophilia (syn. Stenotrophomonas maltophilia) isolated from soils with Chromobacterium violaceum reporter has revealed no strains synthesizing these signal molecules; 26 strains analyzed with Agrobacterium tumefaciens reporter showed the same result. PMID:15058194

  13. Discovery of Potent, Orally Bioavailable, Small-Molecule Inhibitors of WNT Signaling from a Cell-Based Pathway Screen

    PubMed Central

    2015-01-01

    WNT signaling is frequently deregulated in malignancy, particularly in colon cancer, and plays a key role in the generation and maintenance of cancer stem cells. We report the discovery and optimization of a 3,4,5-trisubstituted pyridine 9 using a high-throughput cell-based reporter assay of WNT pathway activity. We demonstrate a twisted conformation about the pyridine–piperidine bond of 9 by small-molecule X-ray crystallography. Medicinal chemistry optimization to maintain this twisted conformation, cognisant of physicochemical properties likely to maintain good cell permeability, led to 74 (CCT251545), a potent small-molecule inhibitor of WNT signaling with good oral pharmacokinetics. We demonstrate inhibition of WNT pathway activity in a solid human tumor xenograft model with evidence for tumor growth inhibition following oral dosing. This work provides a successful example of hypothesis-driven medicinal chemistry optimization from a singleton hit against a cell-based pathway assay without knowledge of the biochemical target. PMID:25680029

  14. Clinical development of galunisertib (LY2157299 monohydrate), a small molecule inhibitor of transforming growth factor-beta signaling pathway

    PubMed Central

    Herbertz, Stephan; Sawyer, J Scott; Stauber, Anja J; Gueorguieva, Ivelina; Driscoll, Kyla E; Estrem, Shawn T; Cleverly, Ann L; Desaiah, Durisala; Guba, Susan C; Benhadji, Karim A; Slapak, Christopher A; Lahn, Michael M

    2015-01-01

    Transforming growth factor-beta (TGF-β) signaling regulates a wide range of biological processes. TGF-β plays an important role in tumorigenesis and contributes to the hallmarks of cancer, including tumor proliferation, invasion and metastasis, inflammation, angiogenesis, and escape of immune surveillance. There are several pharmacological approaches to block TGF-β signaling, such as monoclonal antibodies, vaccines, antisense oligonucleotides, and small molecule inhibitors. Galunisertib (LY2157299 monohydrate) is an oral small molecule inhibitor of the TGF-β receptor I kinase that specifically downregulates the phosphorylation of SMAD2, abrogating activation of the canonical pathway. Furthermore, galunisertib has antitumor activity in tumor-bearing animal models such as breast, colon, lung cancers, and hepatocellular carcinoma. Continuous long-term exposure to galunisertib caused cardiac toxicities in animals requiring adoption of a pharmacokinetic/pharmacodynamic-based dosing strategy to allow further development. The use of such a pharmacokinetic/pharmacodynamic model defined a therapeutic window with an appropriate safety profile that enabled the clinical investigation of galunisertib. These efforts resulted in an intermittent dosing regimen (14 days on/14 days off, on a 28-day cycle) of galunisertib for all ongoing trials. Galunisertib is being investigated either as monotherapy or in combination with standard antitumor regimens (including nivolumab) in patients with cancer with high unmet medical needs such as glioblastoma, pancreatic cancer, and hepatocellular carcinoma. The present review summarizes the past and current experiences with different pharmacological treatments that enabled galunisertib to be investigated in patients. PMID:26309397

  15. Clinical development of galunisertib (LY2157299 monohydrate), a small molecule inhibitor of transforming growth factor-beta signaling pathway.

    PubMed

    Herbertz, Stephan; Sawyer, J Scott; Stauber, Anja J; Gueorguieva, Ivelina; Driscoll, Kyla E; Estrem, Shawn T; Cleverly, Ann L; Desaiah, Durisala; Guba, Susan C; Benhadji, Karim A; Slapak, Christopher A; Lahn, Michael M

    2015-01-01

    Transforming growth factor-beta (TGF-β) signaling regulates a wide range of biological processes. TGF-β plays an important role in tumorigenesis and contributes to the hallmarks of cancer, including tumor proliferation, invasion and metastasis, inflammation, angiogenesis, and escape of immune surveillance. There are several pharmacological approaches to block TGF-β signaling, such as monoclonal antibodies, vaccines, antisense oligonucleotides, and small molecule inhibitors. Galunisertib (LY2157299 monohydrate) is an oral small molecule inhibitor of the TGF-β receptor I kinase that specifically downregulates the phosphorylation of SMAD2, abrogating activation of the canonical pathway. Furthermore, galunisertib has antitumor activity in tumor-bearing animal models such as breast, colon, lung cancers, and hepatocellular carcinoma. Continuous long-term exposure to galunisertib caused cardiac toxicities in animals requiring adoption of a pharmacokinetic/pharmacodynamic-based dosing strategy to allow further development. The use of such a pharmacokinetic/pharmacodynamic model defined a therapeutic window with an appropriate safety profile that enabled the clinical investigation of galunisertib. These efforts resulted in an intermittent dosing regimen (14 days on/14 days off, on a 28-day cycle) of galunisertib for all ongoing trials. Galunisertib is being investigated either as monotherapy or in combination with standard antitumor regimens (including nivolumab) in patients with cancer with high unmet medical needs such as glioblastoma, pancreatic cancer, and hepatocellular carcinoma. The present review summarizes the past and current experiences with different pharmacological treatments that enabled galunisertib to be investigated in patients. PMID:26309397

  16. Zearalenone Mycotoxin Affects Immune Mediators, MAPK Signalling Molecules, Nuclear Receptors and Genome-Wide Gene Expression in Pig Spleen

    PubMed Central

    Pistol, Gina Cecilia; Braicu, Cornelia; Motiu, Monica; Gras, Mihail Alexandru; Marin, Daniela Eliza; Stancu, Mariana; Calin, Loredana; Israel-Roming, Florentina; Berindan-Neagoe, Ioana; Taranu, Ionelia

    2015-01-01

    The toxicity of zearalenone (ZEA) was evaluated in swine spleen, a key organ for the innate and adaptative immune response. Weaned pigs were fed for 18 days with a control or a ZEA contaminated diet. The effect of ZEA was assessed on wide genome expression, pro- (TNF-α, IL-8, IL-6, IL-1β, IFN-γ) and anti-inflammatory (IL-10, IL-4) cytokines, other molecules involved in inflammatory processes (MMPs/TIMPs), as well as signaling molecules, (p38/JNK1/JNK2-MAPKs) and nuclear receptors (PPARγ/NFkB/AP-1/STAT3/c-JUN). Microarray analysis showed that 46% of total number of differentially expressed genes was involved in cellular signaling pathway, 13% in cytokine network and 10% in the inflammatory response. ZEA increased expression and synthesis of pro- inflammatory (TNF-α, IL-8, IL-6, IL-1β) and had no effect on IFN-γ, IL-4 and IL-10 cytokines in spleen. The inflammatory stimulation might be a consequence of JNK pathway activation rather than of p-38MAPK and NF-kB involvement whose gene and protein expression were suppressed by ZEA action. In summary, our findings indicated the role of ZEA as an immune disruptor at spleen level. PMID:26011631

  17. Isolation and Molecular Characterization of Biofouling Bacteria and Profiling of Quorum Sensing Signal Molecules from Membrane Bioreactor Activated Sludge

    PubMed Central

    Lade, Harshad; Paul, Diby; Kweon, Ji Hyang

    2014-01-01

    The formation of biofilm in a membrane bioreactor depends on the production of various signaling molecules like N-acyl homoserine lactones (AHLs). In the present study, a total of 200 bacterial strains were isolated from membrane bioreactor activated sludge and screened for AHLs production using two biosensor systems, Chromobacterium violaceum CV026 and Agrobacterium tumefaciens A136. A correlation between AHLs production and biofilm formation has been made among screened AHLs producing strains. The 16S rRNA gene sequence analysis revealed the dominance of Aeromonas and Enterobacter sp. in AHLs production; however few a species of Serratia, Leclercia, Pseudomonas, Klebsiella, Raoultella and Citrobacter were also identified. The chromatographic characterization of sludge extract showed the presence of a broad range of quorum sensing signal molecules. Further identification of sludge AHLs by thin layer chromatography bioassay and high performance liquid chromatography confirms the presence of C4-HSL, C6-HSL, C8-HSL, 3-oxo-C8-HSL, C10-HSL, C12-HSL, 3-oxo-C12-HSL and C14-HSL. The occurrence of AHLs in sludge extract and dominance of Aeromonas and Enterobacter sp. in activated sludge suggests the key role of these bacterial strains in AHLs production and thereby membrane fouling. PMID:24499972

  18. Zearalenone mycotoxin affects immune mediators, MAPK signalling molecules, nuclear receptors and genome-wide gene expression in pig spleen.

    PubMed

    Pistol, Gina Cecilia; Braicu, Cornelia; Motiu, Monica; Gras, Mihail Alexandru; Marin, Daniela Eliza; Stancu, Mariana; Calin, Loredana; Israel-Roming, Florentina; Berindan-Neagoe, Ioana; Taranu, Ionelia

    2015-01-01

    The toxicity of zearalenone (ZEA) was evaluated in swine spleen, a key organ for the innate and adaptative immune response. Weaned pigs were fed for 18 days with a control or a ZEA contaminated diet. The effect of ZEA was assessed on wide genome expression, pro- (TNF-α, IL-8, IL-6, IL-1β, IFN-γ) and anti-inflammatory (IL-10, IL-4) cytokines, other molecules involved in inflammatory processes (MMPs/TIMPs), as well as signaling molecules, (p38/JNK1/JNK2-MAPKs) and nuclear receptors (PPARγ/NFkB/AP-1/STAT3/c-JUN). Microarray analysis showed that 46% of total number of differentially expressed genes was involved in cellular signaling pathway, 13% in cytokine network and 10% in the inflammatory response. ZEA increased expression and synthesis of pro- inflammatory (TNF-α, IL-8, IL-6, IL-1β) and had no effect on IFN-γ, IL-4 and IL-10 cytokines in spleen. The inflammatory stimulation might be a consequence of JNK pathway activation rather than of p-38MAPK and NF-kB involvement whose gene and protein expression were suppressed by ZEA action. In summary, our findings indicated the role of ZEA as an immune disruptor at spleen level. PMID:26011631

  19. NTB-A Receptor Crystal Structure: Insights into Homophilic Interactions in the Signaling Lymphocytic Activation Molecule Receptor Family

    SciTech Connect

    Cao,E.; Ramagopal, U.; Fedorov, A.; Fedorov, E.; Yan, Q.; Lary, J.; Cole, J.; Nathenson, S.; Almo, S.

    2006-01-01

    The signaling lymphocytic activation molecule (SLAM) family includes homophilic and heterophilic receptors that regulate both innate and adaptive immunity. The ectodomains of most SLAM family members are composed of an N-terminal IgV domain and a C-terminal IgC2 domain. NK-T-B-antigen (NTB-A) is a homophilic receptor that stimulates cytotoxicity in natural killer (NK) cells, regulates bactericidal activities in neutrophils, and potentiates T helper 2 (Th2) responses. The 3.0 {angstrom} crystal structure of the complete NTB-A ectodomain revealed a rod-like monomer that self-associates to form a highly kinked dimer spanning an end-to-end distance of {approx}100 {angstrom}. The NTB-A homophilic and CD2-CD58 heterophilic dimers show overall structural similarities but differ in detailed organization and physicochemical properties of their respective interfaces. The NTB-A structure suggests a mechanism responsible for binding specificity within the SLAM family and imposes physical constraints relevant to the colocalization of SLAM-family proteins with other signaling molecules in the immunological synapse.

  20. Regulation of PI3K by PKC and MARCKS: Single-Molecule Analysis of a Reconstituted Signaling Pathway.

    PubMed

    Ziemba, Brian P; Burke, John E; Masson, Glenn; Williams, Roger L; Falke, Joseph J

    2016-04-26

    In chemotaxing ameboid cells, a complex leading-edge signaling circuit forms on the cytoplasmic leaflet of the plasma membrane and directs both actin and membrane remodeling to propel the leading edge up an attractant gradient. This leading-edge circuit includes a putative amplification module in which Ca(2+)-protein kinase C (Ca(2+)-PKC) is hypothesized to phosphorylate myristoylated alanine-rich C kinase substrate (MARCKS) and release phosphatidylinositol-4,5-bisphosphate (PIP2), thereby stimulating production of the signaling lipid phosphatidylinositol-3,4,5-trisphosphate (PIP3) by the lipid kinase phosphoinositide-3-kinase (PI3K). We investigated this hypothesized Ca(2+)-PKC-MARCKS-PIP2-PI3K-PIP3 amplification module and tested its key predictions using single-molecule fluorescence to measure the surface densities and activities of its protein components. Our findings demonstrate that together Ca(2+)-PKC and the PIP2-binding peptide of MARCKS modulate the level of free PIP2, which serves as both a docking target and substrate lipid for PI3K. In the off state of the amplification module, the MARCKS peptide sequesters PIP2 and thereby inhibits PI3K binding to the membrane. In the on state, Ca(2+)-PKC phosphorylation of the MARCKS peptide reverses the PIP2 sequestration, thereby releasing multiple PIP2 molecules that recruit multiple active PI3K molecules to the membrane surface. These findings 1) show that the Ca(2+)-PKC-MARCKS-PIP2-PI3K-PIP3 system functions as an activation module in vitro, 2) reveal the molecular mechanism of activation, 3) are consistent with available in vivo data, and 4) yield additional predictions that are testable in live cells. More broadly, the Ca(2+)-PKC-stimulated release of free PIP2 may well regulate the membrane association of other PIP2-binding proteins, and the findings illustrate the power of single-molecule analysis to elucidate key dynamic and mechanistic features of multiprotein signaling pathways on membrane surfaces

  1. Gene Expression Profiling Identifies Interferon Signalling Molecules and IGFBP3 in Human Degenerative Annulus Fibrosus.

    PubMed

    Kazezian, Zepur; Gawri, Rahul; Haglund, Lisbet; Ouellet, Jean; Mwale, Fackson; Tarrant, Finbarr; O'Gaora, Peadar; Pandit, Abhay; Alini, Mauro; Grad, Sibylle

    2015-01-01

    Low back pain is a major cause of disability especially for people between 20 and 50 years of age. As a costly healthcare problem, it imposes a serious socio-economic burden. Current surgical therapies fail to replace the normal disc in facilitating spinal movements and absorbing load. The focus of regenerative medicine is on identifying biomarkers and signalling pathways to improve our understanding about cascades of disc degeneration and allow for the design of specific therapies. We hypothesized that comparing microarray profiles from degenerative and non-degenerative discs will lead to the identification of dysregulated signalling and pathophysiological targets. Microarray data sets were generated from human annulus fibrosus cells and analysed using IPA ingenuity pathway analysis. Gene expression values were validated by qRT-PCR, and respective proteins were identified by immunohistochemistry. Microarray analysis revealed 238 differentially expressed genes in the degenerative annulus fibrosus. Seventeen of the dysregulated molecular markers showed log2-fold changes greater than ±1.5. Various dysregulated cellular functions, including cell proliferation and inflammatory response, were identified. The most significant canonical pathway induced in degenerative annulus fibrosus was found to be the interferon pathway. This study indicates interferon-alpha signalling pathway activation with IFIT3 and IGFBP3 up-regulation, which may affect cellular function in human degenerative disc. PMID:26489762

  2. The Aryl Hydrocarbon Receptor: A Key Bridging Molecule of External and Internal Chemical Signals

    PubMed Central

    Tian, Jijing; Feng, Yu; Fu, Hualing; Xie, Heidi Qunhui; Jiang, Joy Xiaosong; Zhao, Bin

    2015-01-01

    The aryl hydrocarbon receptor (AhR) is a highly evolutionary conserved, ligand-activated transcription factor that is best known to mediate the toxicities of dioxins and dioxin-like compounds. Phenotype of AhR-null mice, together with the recent discovery of a variety of endogenous and plant-derived ligands, point to the integral roles of AhR in normal cell physiology, in addition to its roles in sensing the environmental chemicals. Here, we summarize the current knowledge about AhR signaling pathways, its ligands and AhR-mediated effects on cell specialization, host defense and detoxification. AhR-mediated health effects particularly in liver, immune, and nervous systems, as well as in tumorgenesis are discussed. Dioxin-initiated embryotoxicity and immunosuppressive effects in fish and birds are reviewed. Recent data demonstrate that AhR is a convergence point of multiple signaling pathways that inform the cell of its external and internal environments. As such, AhR pathway is a promising potential target for therapeutics targeting nervous, liver, and autoimmune diseases through AhR ligand-mediated interventions and other perturbations of AhR signaling. Additionally, using available laboratory data obtained on animal models, AhR-centered adverse outcome pathway analysis is useful in reexamining known and potential adverse outcomes of specific or mixed compounds on wildlife. PMID:26079192

  3. Gene Expression Profiling Identifies Interferon Signalling Molecules and IGFBP3 in Human Degenerative Annulus Fibrosus

    PubMed Central

    Kazezian, Zepur; Gawri, Rahul; Haglund, Lisbet; Ouellet, Jean; Mwale, Fackson; Tarrant, Finbarr; O’Gaora, Peadar; Pandit, Abhay; Alini, Mauro; Grad, Sibylle

    2015-01-01

    Low back pain is a major cause of disability especially for people between 20 and 50 years of age. As a costly healthcare problem, it imposes a serious socio-economic burden. Current surgical therapies fail to replace the normal disc in facilitating spinal movements and absorbing load. The focus of regenerative medicine is on identifying biomarkers and signalling pathways to improve our understanding about cascades of disc degeneration and allow for the design of specific therapies. We hypothesized that comparing microarray profiles from degenerative and non-degenerative discs will lead to the identification of dysregulated signalling and pathophysiological targets. Microarray data sets were generated from human annulus fibrosus cells and analysed using IPA ingenuity pathway analysis. Gene expression values were validated by qRT-PCR, and respective proteins were identified by immunohistochemistry. Microarray analysis revealed 238 differentially expressed genes in the degenerative annulus fibrosus. Seventeen of the dysregulated molecular markers showed log2-fold changes greater than ±1.5. Various dysregulated cellular functions, including cell proliferation and inflammatory response, were identified. The most significant canonical pathway induced in degenerative annulus fibrosus was found to be the interferon pathway. This study indicates interferon-alpha signalling pathway activation with IFIT3 and IGFBP3 up-regulation, which may affect cellular function in human degenerative disc. PMID:26489762

  4. FIA functions as an early signal component of abscisic acid signal cascade in Vicia faba guard cells.

    PubMed

    Sugiyama, Yusuke; Uraji, Misugi; Watanabe-Sugimoto, Megumi; Okuma, Eiji; Munemasa, Shintaro; Shimoishi, Yasuaki; Nakamura, Yoshimasa; Mori, Izumi C; Iwai, Sumio; Murata, Yoshiyuki

    2012-02-01

    An abscisic acid (ABA)-insensitive Vicia faba mutant, fia (fava bean impaired in ABA-induced stomatal closure) had previously been isolated. In this study, it was investigated how FIA functions in ABA signalling in guard cells of Vicia faba. Unlike ABA, methyl jasmonate (MeJA), H(2)O(2), and nitric oxide (NO) induced stomatal closure in the fia mutant. ABA did not induce production of either reactive oxygen species or NO in the mutant. Moreover, ABA did not suppress inward-rectifying K(+) (K(in)) currents or activate ABA-activated protein kinase (AAPK) in mutant guard cells. These results suggest that FIA functions as an early signal component upstream of AAPK activation in ABA signalling but does not function in MeJA signalling in guard cells of Vicia faba. PMID:22131163

  5. Discovery of small molecule inhibitors of MyD88-dependent signaling pathways using a computational screen

    PubMed Central

    Olson, Mark A.; Lee, Michael S.; Kissner, Teri L.; Alam, Shahabuddin; Waugh, David S.; Saikh, Kamal U.

    2015-01-01

    In this study, we used high-throughput computational screening to discover drug-like inhibitors of the host MyD88 protein-protein signaling interaction implicated in the potentially lethal immune response associated with Staphylococcal enterotoxins. We built a protein-protein dimeric docking model of the Toll-interleukin receptor (TIR)-domain of MyD88 and identified a binding site for docking small molecules. Computational screening of 5 million drug-like compounds led to testing of 30 small molecules; one of these molecules inhibits the TIR-TIR domain interaction and attenuates pro-inflammatory cytokine production in human primary cell cultures. Compounds chemically similar to this hit from the PubChem database were observed to be more potent with improved drug-like properties. Most of these 2nd generation compounds inhibit Staphylococcal enterotoxin B (SEB)-induced TNF-α, IFN-γ, IL-6, and IL-1β production at 2–10 μM in human primary cells. Biochemical analysis and a cell-based reporter assay revealed that the most promising compound, T6167923, disrupts MyD88 homodimeric formation, which is critical for its signaling function. Furthermore, we observed that administration of a single dose of T6167923 completely protects mice from lethal SEB-induced toxic shock. In summary, our in silico approach has identified anti-inflammatory inhibitors against in vitro and in vivo toxin exposure with promise to treat other MyD88-related pro-inflammatory diseases. PMID:26381092

  6. Input overload: Contributions of retinoic acid signaling feedback mechanisms to heart development and teratogenesis.

    PubMed

    D'Aniello, Enrico; Waxman, Joshua S

    2015-03-01

    Appropriate levels of retinoic acid (RA) signaling are critical for normal heart development in vertebrates. A fascinating property of RA signaling is the thoroughness by which positive and negative feedback are employed to promote proper embryonic RA levels. In the present short review, we first cover the advancement of hypotheses regarding the impact of RA signaling on cardiac specification. We then discuss our current understanding of RA signaling feedback mechanisms and the implications of recent studies, which have indicated improperly maintained RA signaling feedback can be a contributing factor to developmental malformations. PMID:25418431

  7. Retinoic Acid Signaling Regulates Differential Expression of the Tandemly-Duplicated Long Wavelength-Sensitive Cone Opsin Genes in Zebrafish

    PubMed Central

    Frey, Ruth A.; Hunter, Samuel S.; Ashino, Ryuichi; Kawamura, Shoji; Stenkamp, Deborah L.

    2015-01-01

    The signaling molecule retinoic acid (RA) regulates rod and cone photoreceptor fate, differentiation, and survival. Here we elucidate the role of RA in differential regulation of the tandemly-duplicated long wavelength-sensitive (LWS) cone opsin genes. Zebrafish embryos were treated with RA from 48 hours post-fertilization (hpf) to 75 hpf, and RNA was isolated from eyes for microarray analysis. ~170 genes showed significantly altered expression, including several transcription factors and components of cellular signaling pathways. Of interest, the LWS1 opsin gene was strongly upregulated by RA. LWS1 is the upstream member of the tandemly duplicated LWS opsin array and is normally not expressed embryonically. Embryos treated with RA 48 hpf to 100 hpf or beyond showed significant reductions in LWS2-expressing cones in favor of LWS1-expressing cones. The LWS reporter line, LWS-PAC(H) provided evidence that individual LWS cones switched from LWS2 to LWS1 expression in response to RA. The RA signaling reporter line, RARE:YFP indicated that increased RA signaling in cones was associated with this opsin switch, and experimental reduction of RA signaling in larvae at the normal time of onset of LWS1 expression significantly inhibited LWS1 expression. A role for endogenous RA signaling in regulating differential expression of the LWS genes in postmitotic cones was further supported by the presence of an RA signaling domain in ventral retina of juvenile zebrafish that coincided with a ventral zone of LWS1 expression. This is the first evidence that an extracellular signal may regulate differential expression of opsin genes in a tandemly duplicated array. PMID:26296154

  8. Small-molecule agonists and antagonists of F-box protein–substrate interactions in auxin perception and signaling

    PubMed Central

    Hayashi, Ken-ichiro; Tan, Xu; Zheng, Ning; Hatate, Tatsuya; Kimura, Yoshio; Kepinski, Stefan; Nozaki, Hiroshi

    2008-01-01

    The regulation of gene expression by the hormone auxin is a crucial mechanism in plant development. We have shown that the Arabidopsis F-box protein TIR1 is a receptor for auxin, and our recent structural work has revealed the molecular mechanism of auxin perception. TIR1 is the substrate receptor of the ubiquitin–ligase complex SCFTIR1. Auxin binding enhances the interaction between TIR1 and its substrates, the Aux/IAA repressors, thereby promoting the ubiquitination and degradation of Aux/IAAs, altering the expression of hundreds of genes. TIR1 is the prototype of a new class of hormone receptor and the first example of an SCF ubiquitin-ligase modulated by a small molecule. Here, we describe the design, synthesis, and characterization of a series of auxin agonists and antagonists. We show these molecules are specific to TIR1-mediated events in Arabidopsis, and their mode of action in binding to TIR1 is confirmed by x-ray crystallographic analysis. Further, we demonstrate the utility of these probes for the analysis of TIR1-mediated auxin signaling in the moss Physcomitrella patens. Our work not only provides a useful tool for plant chemical biology but also demonstrates an example of a specific small-molecule inhibitor of F-box protein–substrate recruitment. Substrate recognition and subsequent ubiquitination by SCF-type ubiquitin ligases are central to many cellular processes in eukaryotes, and ubiquitin-ligase function is affected in several human diseases. Our work supports the idea that it may be possible to design small-molecule agents to modulate ubiquitin-ligase function therapeutically. PMID:18391211

  9. [Role of NO signal in ABA-induced phenolic acids accumulation in Salvia miltiorrhiza hairy roots].

    PubMed

    Shen, Lihong; Ren, Jiahui; Jin, Wenfang; Wang, Ruijie; Ni, Chunhong; Tong, Mengjiao; Liang, Zongsuo; Yang, Dongfeng

    2016-02-01

    To investigate roles of nitric oxide (NO) signal in accumulations of phenolic acids in abscisic.acid (ABA)-induced Salvia miltiorrhiza hairy roots, S. miltiorrhiza hairy roots were treated with different concentrations of sodium nitroprusside (SNP)-an exogenous NO donor, for 6 days, and contents of phenolic acids in the hairy roots are determined. Then with treatment of ABA and NO scavenger (2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylimidazoline-1- oxyl-3-oxide, c-PTIO) or NO synthase inhibitor (NG-nitro-L-arginine methyl ester, L-NAME), contents of phenolic acids and expression levels of three key genes involved in phenolic acids biosynthesis were detected. Phenolic acids production in S. miltiorrhiza hairy roots was most significantly improved by 100 µmoL/L SNP. Contents of RA and salvianolic acid B increased by 3 and 4 folds. ABA significantly improved transcript levels of PAL (phenylalanine ammonia lyase), TAT (tyrosine aminotransferase) and RAS (rosmarinic acid synthase), and increased phenolic acids accumulations. However, with treatments of ABA+c-PTIO or ABA+L-NAME, accumulations of phenolic acids and expression levels of the three key genes were significantly inhibited. Both NO and ABA can increase accumulations of phenolic acids in S. miltiorrhiza hairy roots. NO signal probably mediates the ABA-induced phenolic acids production. PMID:27382772

  10. Ozone: An Air Pollutant Acting as a Plant-Signaling Molecule

    NASA Astrophysics Data System (ADS)

    Sandermann, Heinrich, Jr.

    The air pollutant ozone has recently been found to trigger plant signal transduction chains resembling those induced by fungal and viral pathogens. Chloroplast-related functions are generally inhibited, while genes of antioxidative and pathogen defense are activated. The resulting perturbation of plant metabolism leads to higher susceptibility (or in certain cases higher tolerance) for other abiotic and biotic stressors. This mechanism of action links ozone by some criteria to "novel" forest decline and to agricultural crop loss. Further progress appears to depend on coordinated long-term laboratory and field experiments.

  11. Enhancement of Single Molecule Fluorescence Signals by Colloidal Silver Nanoparticles in Studies of Protein Translation

    PubMed Central

    Bharill, Shashank; Chen, Chunlai; Stevens, Benjamin; Kaur, Jaskiran; Smilansky, Zeev; Mandecki, Wlodek; Gryczynski, Ignacy; Gryczynski, Zygmunt; Cooperman, Barry S.; Goldman, Yale E.

    2011-01-01

    Metal enhanced fluorescence (MEF) increased total photon emission of Cy3- and Cy5-labeled ribosomal initiation complexes near 50 nm silver particles 4- and 5.5-fold respectively. Fluorescence intensity fluctuations above shot noise, at 0.1 – 5 Hz, were greater on silver particles. Overall signal to noise ratio was similar or slightly improved near the particles. Proximity to silver particles did not compromise ribosome function, as measured by codon-dependent binding of fluorescent tRNA, dynamics of fluorescence resonance energy transfer between adjacent tRNAs in the ribosome, and tRNA translocation induced by elongation factor G. PMID:21158483

  12. Independent and Cooperative Roles of Adaptor Molecules in Proximal Signaling during FcɛRI-Mediated Mast Cell Activation▿

    PubMed Central

    Kambayashi, Taku; Okumura, Mariko; Baker, Rebecca G.; Hsu, Chih-Jung; Baumgart, Tobias; Zhang, Weiguo; Koretzky, Gary A.

    2010-01-01

    Activation through FcɛRI, a high-affinity IgE-binding receptor, is critical for mast cell function during allergy. The formation of a multimolecular proximal signaling complex nucleated by the adaptor molecules SLP-76 and LAT1 is required for activation through this receptor. Based on previous T-cell studies, current dogma dictates that LAT1 is required for plasma membrane recruitment and function of SLP-76. Unexpectedly, we found that the recruitment and phosphorylation of SLP-76 were preserved in LAT1−/− mast cells and that SLP-76−/− and LAT1−/− mast cells harbored distinct functional and biochemical defects. The LAT1-like molecule LAT2 was responsible for the preserved membrane localization and phosphorylation of SLP-76 in LAT1−/− mast cells. Although LAT2 supported SLP-76 phosphorylation and recruitment to the plasma membrane, LAT2 only partially compensated for LAT1-mediated cell signaling due to its decreased ability to stabilize interactions with phospholipase Cγ (PLCγ). Comparison of SLP-76−/− LAT1−/− and SLP-76−/− mast cells revealed that some functions of LAT1 could occur independently of SLP-76. We propose that while SLP-76 and LAT1 depend on each other for many of their functions, LAT2/SLP-76 interactions and SLP-76-independent LAT1 functions also mediate a positive signaling pathway downstream of FcɛRI in mast cells. PMID:20606011

  13. Estrogen down-regulates nicotine-induced adhesion molecule expression via nongenomic signal pathway in endothelial cells.

    PubMed

    Wang, Yajing; Wang, Zhaoxia; Wang, Lianyun; Zhou, Ying; Zhao, Yangxing; Liu, Liming; Yao, Chenjiang; Qiao, Zhongdong

    2006-06-01

    Although gonadal hormone mostly causes genotropic actions through the members of nuclear receptor family, it also can regulate these actions via membrane receptor. To explore the possibility of plasma membrane estrogen receptors (mER) mediating genotropic events, we have investigated estrogen's effect on nicotine-stimulated adhesion molecule expression and evaluated whether this effect depends on calcium, MAPK signal pathway. Fluorescence Spectroscopy analysis of Ca2+ from human umbilical vein endothelial cells (HUVECs) showed through mER, estrogen induced a rapid rise of intracellular free Ca2+ concentration and this rise could not be inhibited by tamoxifen (classic ER inhibitor). In the context of nicotine stimulating, however, estrogen attenuated phosphorylation of mitogen-activated protein kinase (MAPK) family members, extracellular signal regulated kinase 1/2 (ERK1/2), p38 but not c-Jun-N-terminal kinase (JNK) in HUVECs and this effect could not still be prevented by tamoxifen. In the meantime, estrogen also down-regulated surface/soluble vascular cell adhesion molecule (VCAM-1, sVCAM-1) and endothelial selectin (E-selectin, sE-selectin) levels, which was not abolished by tamoxifen either. Moreover, calcium chelator BAPTA, ERK1/2 inhibitor PD98059, p38 inhibitor SB203580 significantly reduced the production of nicotine-activated surface/soluble VCAM-1 and E-selectin and both of the remained levels were no longer regulated by estrogen. Our study here provides the information of decrease effect of mER-mediated estrogen through Ca2+ and ERK1/2, p38 MAPK signaling pathway on nicotine-stimulated expression of surface/soluble VCAM-1 and E-selectin in HUVECs. PMID:16644474

  14. Specific cellular signal-transduction responses to in vivo combination therapy with ATRA, valproic acid and theophylline in acute myeloid leukemia.

    PubMed

    Skavland, J; Jørgensen, K M; Hadziavdic, K; Hovland, R; Jonassen, I; Bruserud, O; Gjertsen, B T

    2011-02-01

    Acute myeloid leukemia (AML) frequently comprises mutations in genes that cause perturbation in intracellular signaling pathways, thereby altering normal responses to growth factors and cytokines. Such oncogenic cellular signal transduction may be therapeutic if targeted directly or through epigenetic regulation. We treated 24 selected elderly AML patients with all-trans retinoic acid for 2 days before adding theophylline and the histone deacetylase inhibitor valproic acid (ClinicalTrials.gov NCT00175812; EudraCT no. 2004-001663-22), and sampled 11 patients for peripheral blood at day 0, 2 and 7 for single-cell analysis of basal level and signal-transduction responses to relevant myeloid growth factors (granulocyte-colony-stimulating factor, granulocyte/macrophage-colony-stimulating factor, interleukin-3, Flt3L, stem cell factor, erythropoietin, CXCL-12) on 10 signaling molecules (CREB, STAT1/3/5, p38, Erk1/2, Akt, c-Cbl, ZAP70/Syk and rpS6). Pretreatment analysis by unsupervised clustering and principal component analysis divided the patients into three distinguishable signaling clusters (non-potentiated, potentiated basal and potentiated signaling). Signal-transduction pathways were modulated during therapy and patients moved between the clusters. Patients with multiple leukemic clones demonstrated distinct stimulation responses and therapy-induced modulation. Individual signaling profiles together with clinical and hematological information may be used to early identify AML patients in whom epigenetic and signal-transduction targeted therapy is beneficial. PMID:22829110

  15. Specific cellular signal-transduction responses to in vivo combination therapy with ATRA, valproic acid and theophylline in acute myeloid leukemia

    PubMed Central

    Skavland, J; Jørgensen, K M; Hadziavdic, K; Hovland, R; Jonassen, I; Bruserud, Ø; Gjertsen, B T

    2011-01-01

    Acute myeloid leukemia (AML) frequently comprises mutations in genes that cause perturbation in intracellular signaling pathways, thereby altering normal responses to growth factors and cytokines. Such oncogenic cellular signal transduction may be therapeutic if targeted directly or through epigenetic regulation. We treated 24 selected elderly AML patients with all-trans retinoic acid for 2 days before adding theophylline and the histone deacetylase inhibitor valproic acid (ClinicalTrials.gov NCT00175812; EudraCT no. 2004-001663-22), and sampled 11 patients for peripheral blood at day 0, 2 and 7 for single-cell analysis of basal level and signal-transduction responses to relevant myeloid growth factors (granulocyte-colony-stimulating factor, granulocyte/macrophage-colony-stimulating factor, interleukin-3, Flt3L, stem cell factor, erythropoietin, CXCL-12) on 10 signaling molecules (CREB, STAT1/3/5, p38, Erk1/2, Akt, c-Cbl, ZAP70/Syk and rpS6). Pretreatment analysis by unsupervised clustering and principal component analysis divided the patients into three distinguishable signaling clusters (non-potentiated, potentiated basal and potentiated signaling). Signal-transduction pathways were modulated during therapy and patients moved between the clusters. Patients with multiple leukemic clones demonstrated distinct stimulation responses and therapy-induced modulation. Individual signaling profiles together with clinical and hematological information may be used to early identify AML patients in whom epigenetic and signal-transduction targeted therapy is beneficial. PMID:22829110

  16. Adenovirus Type 2-Simian Virus 40 Hybrid Population: Evidence for a Hybrid Deoxyribonucleic Acid Molecule and the Absence of Adenovirus-Encapsidated Circular Simian Virus 40 Deoxyribonucleic Acid

    PubMed Central

    Crumpacker, Clyde S.; Levin, Myron J.; Wiese, William H.; Lewis, Andrew M.; Rowe, Wallace P.

    1970-01-01

    The deoxyribonucleic acid (DNA) from the adenovirus-encapsidated particles of the adenovirus type 2 (Ad2)-simian virus 40 (SV40) hybrid population plaque variant (Ad2++ HEY), known to yield SV40 virus with high efficiency, was studied by equilibrium density centrifugation followed by ribonucleic acid-DNA hybridization employing virus-specific complementary ribonucleic acids synthesized in vitro. These techniques establish linkage between the Ad2 and SV40 components in the adenovirus-encapsidated particles of this population. The linkage is alkali-resistant and presumably covalent; thus, the Ad2 DNA and SV40 DNA are present in a hybrid molecule. Velocity centrifugation studies in alkaline sucrose gradients eliminated the possibility that supercoiled circular SV40 DNA is present in the adenovirus capsids. The DNA obtained from the adenovirus-encapsidated particles of the Ad2++ HEY population appears to consist of nonhybrid Ad2 DNA and Ad2-SV40 hybrid DNA molecules. PMID:4322081

  17. Searching for amino-acid homochirality on Mars with the Mars Organic Molecule Analyzer (MOMA) onboard ExoMars

    NASA Astrophysics Data System (ADS)

    Buch, A.; Freissinet, C.; Sternberg, R.; Brault, A.; Szopa, C.; Claude-Geffroy, C.; Coll, P. J.; Grand, N.; Raulin, F.; Pinick, V.; Goesmann, F.

    2012-12-01

    The joint ESA-Roscosmos Exo-Mars-2018 rover mission plans to seek the signs of a past or a present life on Mars. The Mars Organic Molecule Analyzer (MOMA) experiment onboard theExoMars rover will be a key analytical tool in providing molecular information from Mars solid samples, with a specific focus on the characterization of their organic content. In this purpose, one of MOMA's main instruments is a gas chromatograph-mass spectrometer (GC-MS), which provides a unique ability to characterize a broad range of compounds and allow chemical analyses on volatile and refractory species. The challenge with the analysis of this refractory matter embedded in soil is their primary extraction before their analysis by GC-MS. Since the extraction of organic matter is not possible by liquid solvent extraction, we have developed a method based on the thermodesorption and subsequent derivatization of the organic molecules. The goal of the thermodesorption is to extract the organic matter by heating the sample quickly enough not to degrade its organic content. One of the main focuses is to determine the chirality of this organic matter, notably amino acids. Indeed, on Earth, homochirality of molecules is an indicator for the presence of life. Amino acids appear to bear only the left-handed form (L) in living system. However, other refractory compounds can raise interest: nucleobases, carboxylic acids and PAHs are among molecules supported by life as we know it, and all of them can display chirality. The intrinsic chirality of molecules being thermosensitive, the thermodesorption parameters have been adjusted to occur within a range of temperatures from 150 °C to 300 °C over a period of 30 s to 10 min, depending on the chemical compound. Under these conditions, we have shown that amino acids are not degraded and that their chirality is preserved. Once extracted, refractory molecules with labile hydrogens (e.g. amino acids, nucleobases, carboxylic acids, etc.) are derivatized

  18. Identification of the nuclear export signals that regulate the intracellular localization of the mouse CMP-sialic acid synthetase

    SciTech Connect

    Fujita, Akiko; Sato, Chihiro; Kitajima, Ken. E-mail: kitajima@agr.nagoya-u.ac.jp

    2007-03-30

    The CMP-sialic acid synthetase (CSS) catalyzes the activation of sialic acid (Sia) to CMP-Sia which is a donor substrate of sialyltransferases. The vertebrate CSSs are usually localized in nucleus due to the nuclear localization signal (NLS) on the molecule. In this study, we first point out that a small, but significant population of the mouse CMP-sialic acid synthetase (mCSS) is also present in cytoplasm, though mostly in nucleus. As a mechanism for the localization in cytoplasm, we first identified two nuclear export signals (NESs) in mCSS, based on the localization studies of the potential NES-deleted mCSS mutants as well as the potential NES-tagged eGFP proteins. These two NESs are conserved among mammalian and fish CSSs, but not present in the bacterial or insect CSS. These results suggest that the intracellular localization of vertebrate CSSs is regulated by not only the NLS, but also the NES sequences.

  19. Anion Effects on Sodium Ion and Acid Molecule Adduction to Protein Ions in Electrospray Ionization Mass Spectrometry

    PubMed Central

    Flick, Tawnya G.; Merenbloom, Samuel I.; Williams, Evan R.

    2012-01-01

    Gaseous protein–metal ion and protein–molecule complexes can be readily formed by electrospray ionization (ESI) from aqueous solutions containing proteins and millimolar concentrations of sodium salts of various anions. The extent of sodium and acid molecule adduction to multiply charged protein ions is inversely related and depends strongly on the proton affinity (PA) of the anion, with extensive sodium adduction occurring for anions with PA values greater than ~300 kcal·mol−1 and extensive acid molecule adduction occurring for anions with PA values less than 315 kcal·mol−1. The role of the anion on the extent of sodium and acid molecule adduction does not directly follow the Hofmeister series, suggesting that direct protein–ion interactions may not play a significant role in the observed effect of anions on protein structure in solution. These results indicate that salts with anions that have low PA values may be useful solution-phase additives to minimize nonspecific metal ion adduction in ESI experiments designed to identify specific protein-metal ion interactions. PMID:21952761

  20. Small molecules dorsomorphin and LDN-193189 inhibit myostatin/GDF8 signaling and promote functional myoblast differentiation.

    PubMed

    Horbelt, Daniel; Boergermann, Jan H; Chaikuad, Apirat; Alfano, Ivan; Williams, Eleanor; Lukonin, Ilya; Timmel, Tobias; Bullock, Alex N; Knaus, Petra

    2015-02-01

    GDF8, or myostatin, is a member of the TGF-β superfamily of secreted polypeptide growth factors. GDF8 is a potent negative regulator of myogenesis both in vivo and in vitro. We found that GDF8 signaling was inhibited by the small molecule ATP competitive inhibitors dorsomorphin and LDN-193189. These compounds were previously shown to be potent inhibitors of BMP signaling by binding to the BMP type I receptors ALK1/2/3/6. We present the crystal structure of the type II receptor ActRIIA with dorsomorphin and demonstrate that dorsomorphin or LDN-193189 target GDF8 induced Smad2/3 signaling and repression of myogenic transcription factors. As a result, both inhibitors rescued myogenesis in myoblasts treated with GDF8. As revealed by quantitative live cell microscopy, treatment with dorsomorphin or LDN-193189 promoted the contractile activity of myotubular networks in vitro. We therefore suggest these inhibitors as suitable tools to promote functional myogenesis. PMID:25368322

  1. Single molecule imaging reveals a major role for diffusion in the exploration of ciliary space by signaling receptors

    PubMed Central

    Ye, Fan; Breslow, David K; Koslover, Elena F; Spakowitz, Andrew J; Nelson, W James; Nachury, Maxence V

    2013-01-01

    The dynamic organization of signaling cascades inside primary cilia is key to signal propagation. Yet little is known about the dynamics of ciliary membrane proteins besides a possible role for motor-driven Intraflagellar Transport (IFT). To characterize these dynamics, we imaged single molecules of Somatostatin Receptor 3 (SSTR3, a GPCR) and Smoothened (Smo, a Hedgehog signal transducer) in the ciliary membrane. While IFT trains moved processively from one end of the cilium to the other, single SSTR3 and Smo underwent mostly diffusive behavior interspersed with short periods of directional movements. Statistical subtraction of instant velocities revealed that SSTR3 and Smo spent less than a third of their time undergoing active transport. Finally, SSTR3 and IFT movements could be uncoupled by perturbing either membrane protein diffusion or active transport. Thus ciliary membrane proteins move predominantly by diffusion, and attachment to IFT trains is transient and stochastic rather than processive or spatially determined. DOI: http://dx.doi.org/10.7554/eLife.00654.001 PMID:23930224

  2. The Protein Architecture of Human Secretory Vesicles Reveals Differential Regulation of Signaling Molecule Secretion by Protein Kinases

    PubMed Central

    Taupenot, Laurent; Ziegler, Michael; O'Connor, Daniel T.; Ma, Qi; Smoot, Michael; Ideker, Trey; Hook, Vivian

    2012-01-01

    Secretory vesicles are required for release of chemical messengers to mediate intercellular signaling among human biological systems. It is necessary to define the organization of the protein architecture of the ‘human’ dense core secretory vesicles (DCSV) to understand mechanisms for secretion of signaling molecules essential for cellular regulatory processes. This study, therefore, conducted extensive quantitative proteomics and systems biology analyses of human DCSV purified from human pheochromocytoma. Over 600 human DCSV proteins were identified with quantitative evaluation of over 300 proteins, revealing that most proteins participate in producing peptide hormones and neurotransmitters, enzymes, and the secretory machinery. Systems biology analyses provided a model of interacting DCSV proteins, generating hypotheses for differential intracellular protein kinases A and C signaling pathways. Activation of cellular PKA and PKC pathways resulted in differential secretion of neuropeptides, catecholamines, and β-amyloid of Alzheimer's disease for mediating cell-cell communication. This is the first study to define a model of the protein architecture of human DCSV for human disease and health. PMID:22916103

  3. Small Molecules Dorsomorphin and LDN-193189 Inhibit Myostatin/GDF8 Signaling and Promote Functional Myoblast Differentiation*

    PubMed Central

    Horbelt, Daniel; Boergermann, Jan H.; Chaikuad, Apirat; Alfano, Ivan; Williams, Eleanor; Lukonin, Ilya; Timmel, Tobias; Bullock, Alex N.; Knaus, Petra

    2015-01-01

    GDF8, or myostatin, is a member of the TGF-β superfamily of secreted polypeptide growth factors. GDF8 is a potent negative regulator of myogenesis both in vivo and in vitro. We found that GDF8 signaling was inhibited by the small molecule ATP competitive inhibitors dorsomorphin and LDN-193189. These compounds were previously shown to be potent inhibitors of BMP signaling by binding to the BMP type I receptors ALK1/2/3/6. We present the crystal structure of the type II receptor ActRIIA with dorsomorphin and demonstrate that dorsomorphin or LDN-193189 target GDF8 induced Smad2/3 signaling and repression of myogenic transcription factors. As a result, both inhibitors rescued myogenesis in myoblasts treated with GDF8. As revealed by quantitative live cell microscopy, treatment with dorsomorphin or LDN-193189 promoted the contractile activity of myotubular networks in vitro. We therefore suggest these inhibitors as suitable tools to promote functional myogenesis. PMID:25368322

  4. Expression of GABA Signaling Molecules KCC2, NKCC1, and GAD1 in Cortical Development and Schizophrenia

    PubMed Central

    Lipska, Barbara K.; Ali, Towhid; Mathew, Shiny V.; Law, Amanda J.; Metitiri, Ochuko E.; Straub, Richard E.; Ye, Tianzhang; Colantuoni, Carlo; Herman, Mary M.; Bigelow, Llewellyn B.; Weinberger, Daniel R.; Kleinman, Joel E.

    2011-01-01

    GABA signaling molecules are critical for both human brain development and the pathophysiology of schizophrenia. We examined the expression of transcripts derived from three genes related to GABA signaling [GAD1 (GAD67 and GAD25), SLC12A2 (NKCC1), and SLC12A5 (KCC2)] in the prefrontal cortex (PFC) and hippocampal formation of a large cohort of nonpsychiatric control human brains (n = 240) across the lifespan (from fetal week 14 to 80 years) and in patients with schizophrenia (n = 30–31), using quantitative RT-PCR. We also examined whether a schizophrenia risk-associated promoter SNP in GAD1 (rs3749034) is related to expression of these transcripts. Our studies revealed that development and maturation of both the PFC and hippocampal formation are characterized by progressive switches in expression from GAD25 to GAD67 and from NKCC1 to KCC2. Previous studies have demonstrated that the former leads to GABA synthesis, and the latter leads to switching from excitatory to inhibitory neurotransmission. In the hippocampal formation, GAD25/GAD67 and NKCC1/KCC2 ratios are increased in patients with schizophrenia, reflecting a potentially immature GABA physiology. Remarkably, GAD25/GAD67 and NKCC1/KCC2 expression ratios are associated with rs3749034 genotype, with risk alleles again predicting a relatively less mature pattern. These findings suggest that abnormalities in GABA signaling critical to brain development contribute to genetic risk for schizophrenia. PMID:21795557

  5. Single molecule imaging reveals a major role for diffusion in the exploration of ciliary space by signaling receptors.

    PubMed

    Ye, Fan; Breslow, David K; Koslover, Elena F; Spakowitz, Andrew J; Nelson, W James; Nachury, Maxence V

    2013-01-01

    The dynamic organization of signaling cascades inside primary cilia is key to signal propagation. Yet little is known about the dynamics of ciliary membrane proteins besides a possible role for motor-driven Intraflagellar Transport (IFT). To characterize these dynamics, we imaged single molecules of Somatostatin Receptor 3 (SSTR3, a GPCR) and Smoothened (Smo, a Hedgehog signal transducer) in the ciliary membrane. While IFT trains moved processively from one end of the cilium to the other, single SSTR3 and Smo underwent mostly diffusive behavior interspersed with short periods of directional movements. Statistical subtraction of instant velocities revealed that SSTR3 and Smo spent less than a third of their time undergoing active transport. Finally, SSTR3 and IFT movements could be uncoupled by perturbing either membrane protein diffusion or active transport. Thus ciliary membrane proteins move predominantly by diffusion, and attachment to IFT trains is transient and stochastic rather than processive or spatially determined. DOI:http://dx.doi.org/10.7554/eLife.00654.001. PMID:23930224

  6. Folic Acid Supplementation Stimulates Notch Signaling and Cell Proliferation in Embryonic Neural Stem Cells

    PubMed Central

    Liu, Huan; Huang, Guo-wei; Zhang, Xu-mei; Ren, Da-lin; X. Wilson, John

    2010-01-01

    The present study investigated the effect of folic acid supplementation on the Notch signaling pathway and cell proliferation in rat embryonic neural stem cells (NSCs). The NSCs were isolated from E14–16 rat brain and grown as neurospheres in serum-free suspension culture. Individual cultures were assigned to one of 3 treatment groups that differed according to the concentration of folic acid in the medium: Control (baseline folic acid concentration of 4 mg/l), low folic acid supplementation (4 mg/l above baseline, Folate-L) and high folic acid supplementation (40 mg/l above baseline, Folate-H). NSCs were identified by their expression of immunoreactive nestin and proliferating cells by incorporation of 5'bromo-2'deoxyuridine. Cell proliferation was also assessed by methyl thiazolyl tetrazolium assay. Notch signaling was analyzed by real-time PCR and western blot analyses of the expression of Notch1 and hairy and enhancer of split 5 (Hes5). Supplementation of NSCs with folic acid increased the mRNA and protein expression levels of Notch1 and Hes5. Folic acid supplementation also stimulated NSC proliferation dose-dependently. Embryonic NSCs respond to folic acid supplementation with increased Notch signaling and cell proliferation. This mechanism may mediate the effects of folic acid supplementation on neurogenesis in the embryonic nervous system. PMID:20838574

  7. Visualization of Signaling Molecules During Neutrophil Recruitment in Transgenic Mice Expressing FRET Biosensors.

    PubMed

    Mizuno, Rei; Kamioka, Yuji; Sakai, Yoshiharu; Matsuda, Michiyuki

    2016-01-01

    A number of chemical mediators regulate neutrophil recruitment to inflammatory sites either positively or negatively. Although the actions of each chemical mediator on the intracellular signaling networks controlling cell migration have been studied with neutrophils cultured in vitro, how such chemical mediators act cooperatively or counteractively in vivo remains largely unknown. To understand the mechanisms regulating neutrophil recruitment to the inflamed intestine in vivo, we recently generated transgenic mice expressing biosensors based on FRET (Förster resonance energy transfer) and set up two-photon excitation microscopy to observe the gastrointestinal tract in living mice. By measuring FRET in neutrophils, we showed activity changes of protein kinases in the neutrophils recruited to inflamed intestines. In this chapter, we describe the protocol used to visualize the protein kinase activities in neutrophils of the inflamed intestine of transgenic mice expressing the FRET biosensors. PMID:27246030

  8. Rspo1-activated signalling molecules are sufficient to induce ovarian differentiation in XY medaka (Oryzias latipes)

    PubMed Central

    Zhou, Linyan; Charkraborty, Tapas; Zhou, Qian; Mohapatra, Sipra; Nagahama, Yoshitaka; Zhang, Yueguang

    2016-01-01

    In contrast to our understanding of testicular differentiation, ovarian differentiation is less well understood in vertebrates. In mammals, R-spondin1 (Rspo1), an activator of Wnt/β-catenin signaling pathway, is located upstream of the female sex determination pathway. However, the functions of Rspo1 in ovarian differentiation remain unclear in non-mammalian species. In order to elucidate the detailed functions of Rspo/Wnt signaling pathway in fish sex determination/differentiation, the ectopic expression of the Rspo1 gene was performed in XY medaka (Oryzias latipes). The results obtained demonstrated that the gain of Rspo1 function induced femininity in XY fish. The overexpression of Rspo1 enhanced Wnt4b and β-catenin transcription, and completely suppressed the expression of male-biased genes (Dmy, Gsdf, Sox9a2 and Dmrt1) as well as testicular differentiation. Gonadal reprograming of Rspo1-over-expressed-XY (Rspo1-OV-XY) fish, induced the production of female-biased genes (Cyp19a1a and Foxl2), estradiol-17β production and further female type secondary sexuality. Moreover, Rspo1-OV-XY females were fertile and produced successive generations. Promoter analyses showed that Rspo1 transcription was directly regulated by DM domain genes (Dmy, the sex-determining gene, and Dmrt1) and remained unresponsive to Foxl2. Taken together, our results strongly suggest that Rspo1 is sufficient to activate ovarian development and plays a decisive role in the ovarian differentiation in medaka. PMID:26782368

  9. Rspo1-activated signalling molecules are sufficient to induce ovarian differentiation in XY medaka (Oryzias latipes).

    PubMed

    Zhou, Linyan; Charkraborty, Tapas; Zhou, Qian; Mohapatra, Sipra; Nagahama, Yoshitaka; Zhang, Yueguang

    2016-01-01

    In contrast to our understanding of testicular differentiation, ovarian differentiation is less well understood in vertebrates. In mammals, R-spondin1 (Rspo1), an activator of Wnt/β-catenin signaling pathway, is located upstream of the female sex determination pathway. However, the functions of Rspo1 in ovarian differentiation remain unclear in non-mammalian species. In order to elucidate the detailed functions of Rspo/Wnt signaling pathway in fish sex determination/differentiation, the ectopic expression of the Rspo1 gene was performed in XY medaka (Oryzias latipes). The results obtained demonstrated that the gain of Rspo1 function induced femininity in XY fish. The overexpression of Rspo1 enhanced Wnt4b and β-catenin transcription, and completely suppressed the expression of male-biased genes (Dmy, Gsdf, Sox9a2 and Dmrt1) as well as testicular differentiation. Gonadal reprograming of Rspo1-over-expressed-XY (Rspo1-OV-XY) fish, induced the production of female-biased genes (Cyp19a1a and Foxl2), estradiol-17β production and further female type secondary sexuality. Moreover, Rspo1-OV-XY females were fertile and produced successive generations. Promoter analyses showed that Rspo1 transcription was directly regulated by DM domain genes (Dmy, the sex-determining gene, and Dmrt1) and remained unresponsive to Foxl2. Taken together, our results strongly suggest that Rspo1 is sufficient to activate ovarian development and plays a decisive role in the ovarian differentiation in medaka. PMID:26782368

  10. Nanostructured lipid carrier-loaded hyaluronic acid microneedles for controlled dermal delivery of a lipophilic molecule.

    PubMed

    Lee, Sang Gon; Jeong, Jae Han; Lee, Kyung Min; Jeong, Kyu Ho; Yang, Huisuk; Kim, Miroo; Jung, Hyungil; Lee, Sangkil; Choi, Young Wook

    2014-01-01

    Nanostructured lipid carriers (NLCs) were employed to formulate a lipophilic drug into hydrophilic polymeric microneedles (MNs). Hyaluronic acid (HA) was selected as a hydrophilic and bioerodible polymer to fabricate MNs, and nile red (NR) was used as a model lipophilic molecule. NR-loaded NLCs were consolidated into the HA-based MNs to prepare NLC-loaded MNs (NLC-MNs). A dispersion of NLCs was prepared by high-pressure homogenization after dissolving NR in Labrafil and mixing with melted Compritol, resulting in 268 nm NLCs with a polydispersity index of 0.273. The NLC dispersion showed a controlled release of NR over 24 hours, following Hixson-Crowell's cube root law. After mixing the NLC dispersion with the HA solution, the drawing lithography method was used to fabricate NLC-MNs. The length, base diameter, and tip diameter of the NLC-MNs were approximately 350, 380, and 30 μm, respectively. Fluorescence microscopic imaging of the NLC-MNs helped confirm that the NR-loaded NLCs were distributed evenly throughout the MNs. In a skin permeation study performed using a Franz diffusion cell with minipig dorsal skin, approximately 70% of NR was localized in the skin after 24-hour application of NLC-MNs. Confocal laser scanning microscopy (z-series) of the skin at different depths showed strong fluorescence intensity in the epidermal layer, which appeared to spread out radially with the passage of time. This study indicated that incorporation of drug-loaded NLCs into MNs could represent a promising strategy for controlled dermal delivery of lipophilic drugs. PMID:24403833

  11. Kinase Signaling in Apoptosis Induced by Saturated Fatty Acids in Pancreatic β-Cells.

    PubMed

    Šrámek, Jan; Němcová-Fürstová, Vlasta; Kovář, Jan

    2016-01-01

    Pancreatic β-cell failure and death is considered to be one of the main factors responsible for type 2 diabetes. It is caused by, in addition to hyperglycemia, chronic exposure to increased concentrations of fatty acids, mainly saturated fatty acids. Molecular mechanisms of apoptosis induction by saturated fatty acids in β-cells are not completely clear. It has been proposed that kinase signaling could be involved, particularly, c-Jun N-terminal kinase (JNK), protein kinase C (PKC), p38 mitogen-activated protein kinase (p38 MAPK), extracellular signal-regulated kinase (ERK), and Akt kinases and their pathways. In this review, we discuss these kinases and their signaling pathways with respect to their possible role in apoptosis induction by saturated fatty acids in pancreatic β-cells. PMID:27626409

  12. Surface active molecules: preparation and properties of long chain n-acyl-l-alpha-amino-omega-guanidine alkyl acid derivatives.

    PubMed

    Infante, R; Dominguez, J G; Erra, P; Julia, R; Prats, M

    1984-12-01

    Synopsis A new route for the synthesis of long chain N(alpha)-acyl-l-alpha-amino-omega-guamdine alkyl acid derivatives, with cationic or amphoteric character has been established. The general formula of these compounds is shown below. A physico-chemical and antimicrobial study of these products as a function of the alkyl ester or sodium salt (R), the straight chain length of the fatty acid residue (x) and the number of carbons between the omega-guanidine and omega-carboxyl group (n) has been investigated. The water solubility, surface tension, critical micelle concentration (c.m.c.) and minimum inhibitory concentration (MIC) against Gram-positive and Gram-negative bacteria (including Pseudomonas) has been determined. Dicyclohexylcarbodiimide has been used to condense fatty acids and alpha-amino-omega-guanidine alkyl acids. In these conditions protection of the omega-guanidine group is not necessary. The main characteristic of this synthetic procedure is the use of very mild experimental conditions (temperature, pH) to form the amide linkage which leads to pure optical compounds in high yield in the absence of electrolytes. The results show that some structural modifications, particularly the protection of the carboxyl group, promote variations of the surfactant and antimicrobial properties. Only those molecules with the blocked carboxyl group (cationic molecules, where R = Me, Et or Pr) showed a good surfactant and antimicrobial activity. When the carboxyl group was unprotected (amphoteric molecules, where R = Na(+)) the resulting compounds were inactive. PMID:19467126

  13. 15-oxoeicosatetraenoic acid is a 15-hydroxyprostaglandin dehydrogenase-derived electrophilic mediator of inflammatory signaling pathways

    PubMed Central

    Snyder, Nathaniel W.; Golin-Bisello, Franca; Gao, Yang; Blair, Ian A.; Freeman, Bruce A.; Wendell, Stacy Gelhaus

    2014-01-01

    Bioactive lipids govern cellular homeostasis and pathogenic inflammatory processes. Current dogma holds that bioactive lipids, such as prostaglandins and lipoxins, are inactivated by 15-hydroxyprostaglandin dehydrogenase (15PGDH). In contrast, the present results reveal that catabolic “inactivation” of hydroxylated polyunsaturated fatty acids (PUFAs) yields electrophilic α,β-unsaturated ketone derivatives. These endogenously produced species are chemically reactive signaling mediators that induce tissue protective events. Electrophilic fatty acids diversify the proteome through post-translational alkylation of nucleophilic cysteines in key transcriptional regulatory proteins and enzymes that govern cellular metabolic and inflammatory homeostasis. 15PGDH regulates these processes as it is responsible for the formation of numerous electrophilic fatty acids including the arachidonic acid metabolite, 15-oxoeicosatetraenoic acid (15-oxoETE). Herein, the role of 15-oxoETE in regulating signaling responses is reported. In cell cultures, 15-oxoETE activates Nrf2-regulated antioxidant responses (AR) and inhibits NF-κB-mediated pro-inflammatory responses via IKKβ inhibition. Inhibition of glutathione S-transferases using ethacrynic acid incrementally increased the signaling capacity of 15-oxoETE by decreasing 15-oxoETE-GSH adduct formation. This work demonstrates that 15PGDH plays a role in the regulation of cell and tissue homeostasis via the production of electrophilic fatty acid signaling mediators. PMID:25450232

  14. Acidic intracellular Ca(2+) stores and caveolae in Ca(2+) signaling and diabetes.

    PubMed

    Guerrero-Hernandez, Agustin; Gallegos-Gomez, Martin Leonardo; Sanchez-Vazquez, Victor Hugo; Lopez-Mendez, Maria Cristina

    2014-11-01

    Acidic Ca(2+) stores, particularly lysosomes, are newly discovered players in the well-orchestrated arena of Ca(2+) signaling and we are at the verge of understanding how lysosomes accumulate Ca(2+) and how they release it in response to different chemical, such as NAADP, and physical signals. Additionally, it is now clear that lysosomes play a key role in autophagy, a process that allows cells to recycle components or to eliminate damaged structures to ensure cellular well-being. Moreover, lysosomes are being unraveled as hubs that coordinate both anabolism via insulin signaling and catabolism via AMPK. These acidic vesicles have close contact with the ER and there is a bidirectional movement of information between these two organelles that exquisitely regulates cell survival. Lysosomes also connect with plasma membrane where caveolae are located as specialized regions involved in Ca(2+) and insulin signaling. Alterations of all these signaling pathways are at the core of insulin resistance and diabetes. PMID:25182518

  15. Tumor suppressor microRNAs: Targeted molecules and signaling pathways in breast cancer.

    PubMed

    Asghari, F; Haghnavaz, N; Baradaran, B; Hemmatzadeh, M; Kazemi, T

    2016-07-01

    Breast cancer is the most common type of cancer in women whose prevalence is increasing every year. Common strategies for diagnosis, prognosis and specific treatment of breast cancer need improvements to increase patients' survival. For this reason, there is growing number of efforts world-wide with molecular approaches. With the advent of microRNAs (miRNAs), they have been interested for almost all aspects of tumorgenesis and correlation of breast cancer and microRNAs was discovered for the first time in 2005. MiRNAs form a group of small noncoding RNAs which participate in regulation of gene expression and subsequently several biological processes and pathogenesis of various diseases. As other cancers, miRNAs involved in breast cancer are classified in two groups: the first group is tumor inducing miRNAs (also called oncomirs) that can induce tumor initiation and progression, and their expression is increased in cancerous cells. The second group is tumor suppressor miRNAs. In normal situation, tumor suppressor miRNAs prevent beginning and progression of breast cancer through suppressing the expression of various oncogenes. In this review we will give a general overview about miRNAs and breast cancer, and in the following, more discussion about tumor suppressor miRNAs, with focus on the best known of them and their targeted oncogenes and signaling pathways. Finally, we will point to application of this group of miRNAs in diagnosis, prognosis and treatment of patients. PMID:27261608

  16. Caenorhabditis elegans Recognizes a Bacterial Quorum-sensing Signal Molecule through the AWCON Neuron*

    PubMed Central

    Werner, Kristen M.; Perez, Lark J.; Ghosh, Rajarshi; Semmelhack, Martin F.; Bassler, Bonnie L.

    2014-01-01

    In a process known as quorum sensing, bacteria use chemicals called autoinducers for cell-cell communication. Population-wide detection of autoinducers enables bacteria to orchestrate collective behaviors. In the animal kingdom detection of chemicals is vital for success in locating food, finding hosts, and avoiding predators. This behavior, termed chemotaxis, is especially well studied in the nematode Caenorhabditis elegans. Here we demonstrate that the Vibrio cholerae autoinducer (S)-3-hydroxytridecan-4-one, termed CAI-1, influences chemotaxis in C. elegans. C. elegans prefers V. cholerae that produces CAI-1 over a V. cholerae mutant defective for CAI-1 production. The position of the CAI-1 ketone moiety is the key feature driving CAI-1-directed nematode behavior. CAI-1 is detected by the C. elegans amphid sensory neuron AWCON. Laser ablation of the AWCON cell, but not other amphid sensory neurons, abolished chemoattraction to CAI-1. These analyses define the structural features of a bacterial-produced signal and the nematode chemosensory neuron that permit cross-kingdom interaction. PMID:25092291

  17. Increased signals from short-wavelength-excited fluorescent molecules using sub-Ti:Sapphire wavelengths

    PubMed Central

    NORRIS, G; AMOR, R; DEMPSTER, J; AMOS, W B; MCCONNELL, G

    2012-01-01

    We report the use of an all-solid-state ultrashort pulsed source specifically for two-photon microscopy at wavelengths shorter than those of the conventional Ti:Sapphire laser. Our approach involves sum–frequency mixing of the output from an optical parametric oscillator (λ= 1400–1640 nm) synchronously pumped by a Yb-doped fibre laser (λ= 1064 nm), with the residual pump radiation. This generated an fs-pulsed output tunable in the red spectral region (λ= 620–636 nm, ∼150 mW, 405 fs, 80 MHz, M2∼ 1.3). We demonstrate the performance of our ultrashort pulsed system using fluorescently labelled and autofluorescent tissue, and compare with conventional Ti:Sapphire excitation. We observe a more than 3-fold increase in fluorescence signal intensity using our visible laser source in comparison with the Ti:Sapphire laser for two-photon excitation at equal illumination peak powers of 1.16 kW or less. PMID:23078118

  18. Synthesis of Redox-Active Molecules and Their Signaling Functions During the Expression of Plant Disease Resistance

    PubMed Central

    Skelly, Michael J.

    2013-01-01

    Abstract Significance: Activation of immune responses in plants is associated with a parallel burst of both reactive oxygen intermediates (ROIs) and nitric oxide (NO). The mechanisms by which these small redox-active molecules are synthesized and their signaling functions are critical for plants to defend themselves against pathogen infection. Recent Advances: The synthesis of apoplastic ROIs by plants after pathogen recognition has long been attributed to membrane-bound NAPDH oxidases. However, the emerging data suggest a role for other enzymes in various subcellular locations in ROI production after defense activation. It is becoming widely appreciated that NO exerts its biochemical function through the S-nitrosylation of reactive cysteine thiols on target proteins, constituting a key post-translational modification. Recent evidence suggests that S-nitrosylation of specific defense-related proteins regulates their activity. Critical Issues: The source(s) of NO production after pathogen recognition remain(s) poorly understood. Some NO synthesis can be attributed to the activity of nitrate reductase but to date, no nitric oxide synthase (NOS) has been identified in higher plants. However, the signaling functions of S-nitrosylation are becoming more apparent and thus dissecting the molecular machinery underpinning this redox-based modification is vital to further our understanding of plant disease resistance. Future Directions: In addition to identifying new contributors to the oxidative burst, the discovery of an NOS in higher plants would significantly move the field forward. Since S-nitrosylation has now been confirmed to play various roles in immune signaling, this redox-based modification is a potential target to exploit for improving disease resistance in crop species. Antioxid. Redox Signal. 19, 990–997. PMID:23725342

  19. Chronic prenatal ethanol exposure alters expression of central and peripheral insulin signaling molecules in adult guinea pig offspring.

    PubMed

    Dobson, Christine C; Thevasundaram, Kersh; Mongillo, Daniel L; Winterborn, Andrew; Holloway, Alison C; Brien, James F; Reynolds, James N

    2014-11-01

    Maternal ethanol consumption during pregnancy can produce a range of teratogenic outcomes in offspring. The mechanism of ethanol teratogenicity is multi-faceted, but may involve alterations in insulin and insulin-like growth factor (IGF) signaling pathways. These pathways are not only important for metabolism, but are also critically involved in neuronal survival and plasticity, and they can be altered by chronic prenatal ethanol exposure (CPEE). The objective of this study was to test the hypothesis that CPEE alters expression of insulin and IGF signaling molecules in the prefrontal cortex and liver of adult guinea pig offspring. Pregnant Dunkin-Hartley-strain guinea pigs received ethanol (4 g/kg maternal body weight/day) or isocaloric-sucrose/pair-feeding (nutritional control) throughout gestation. Fasting blood glucose concentration was measured in male and female offspring at postnatal day 150-200, followed by euthanasia, collection of prefrontal cortex and liver, and RNA extraction. IGF-1, IGF-1 receptor (IGF-1R), IGF-2, IGF-2 receptor (IGF-2R), insulin receptor substrate (IRS)-1, IRS-2, and insulin receptor (INSR) mRNA expression levels were measured in tissues using quantitative real-time PCR. The mean maternal blood ethanol concentration was 281 ± 15 mg/dL at 1 h after the second divided dose of ethanol on GD 57. CPEE resulted in increased liver weight in adult offspring, but produced no difference in fasting blood glucose concentration compared with nutritional control. In the liver, CPEE decreased mRNA expression of IGF-1, IGF-1R, and IGF-2, and increased IRS-2 mRNA expression in male offspring only compared with nutritional control. Female CPEE offspring had decreased INSR hepatic mRNA expression compared with male CPEE offspring. In the prefrontal cortex, IRS-2 mRNA expression was increased in CPEE offspring compared with nutritional control. The data demonstrate that CPEE alters both central and peripheral expression of insulin and IGF signaling

  20. Redox-dependent anti-inflammatory signaling actions of unsaturated fatty acids.

    PubMed

    Delmastro-Greenwood, Meghan; Freeman, Bruce A; Wendell, Stacy Gelhaus

    2014-01-01

    Unsaturated fatty acids are metabolized to reactive products that can act as pro- or anti-inflammatory signaling mediators. Electrophilic fatty acid species, including nitro- and oxo-containing fatty acids, display salutary anti-inflammatory and metabolic actions. Electrophilicity can be conferred by both enzymatic and oxidative reactions, via the homolytic addition of nitrogen dioxide to a double bond or via the formation of α,β-unsaturated carbonyl and epoxide substituents. The endogenous formation of electrophilic fatty acids is significant and influenced by diet, metabolic, and inflammatory reactions. Transcriptional regulatory proteins and enzymes can sense the redox status of the surrounding environment upon electrophilic fatty acid adduction of functionally significant, nucleophilic cysteines. Through this covalent and often reversible posttranslational modification, gene expression and metabolic responses are induced. At low concentrations, the pleiotropic signaling actions that are regulated by these protein targets suggest that some classes of electrophilic lipids may be useful for treating metabolic and inflammatory diseases. PMID:24161076

  1. Redox-Dependent Anti-Inflammatory Signaling Actions of Unsaturated Fatty Acids

    PubMed Central

    Delmastro-Greenwood, Meghan; Freeman, Bruce A.; Wendell, Stacy Gelhaus

    2014-01-01

    Unsaturated fatty acids are metabolized to reactive products that can act as pro- or anti-inflammatory signaling mediators. Electrophilic fatty acid species, including nitro- and oxo-containing fatty acids, display salutary anti-inflammatory and metabolic actions. Electrophilicity can be conferred by both enzymatic and oxidative reactions, via the homolytic addition of nitrogen dioxide to a double bond or via the formation of α,β-unsaturated carbonyl and epoxide substituents. The endogenous formation of electrophilic fatty acids is significant and influenced by diet, metabolic, and inflammatory reactions. Transcriptional regulatory proteins and enzymes can sense the redox status of the surrounding environment upon electrophilic fatty acid adduction of functionally significant, nucleophilic cysteines. Through this covalent and often reversible posttranslational modification, gene expression and metabolic responses are induced. At low concentrations, the pleiotropic signaling actions that are regulated by these protein targets suggest that some classes of electrophilic lipids may be useful for treating metabolic and inflammatory diseases. PMID:24161076

  2. Long-chain bases, phosphatidic acid, MAPKs, and reactive oxygen species as nodal signal transducers in stress responses in Arabidopsis

    PubMed Central

    Saucedo-García, Mariana; Gavilanes-Ruíz, Marina; Arce-Cervantes, Oscar

    2015-01-01

    Due to their sessile condition, plants have developed sensitive, fast, and effective ways to contend with environmental changes. These mechanisms operate as informational wires conforming extensive and intricate networks that are connected in several points. The responses are designed as pathways orchestrated by molecules that are transducers of protein and non-protein nature. Their chemical nature imposes selective features such as specificity, formation rate, and generation site to the informational routes. Enzymes such as mitogen-activated protein kinases and non-protein, smaller molecules, such as long-chain bases, phosphatidic acid, and reactive oxygen species are recurrent transducers in the pleiotropic responses to biotic and abiotic stresses in plants. In this review, we considered these four components as nodal points of converging signaling pathways that start from very diverse stimuli and evoke very different responses. These pleiotropic effects may be explained by the potentiality that every one of these four mediators can be expressed from different sources, cellular location, temporality, or magnitude. Here, we review recent advances in our understanding of the interplay of these four specific signaling components in Arabidopsis cells, with an emphasis on drought, cold and pathogen stresses. PMID:25763001

  3. Quantitative Structure of an Acetate Dye Molecule Analogue at the TiO2–Acetic Acid Interface

    PubMed Central

    2016-01-01

    The positions of atoms in and around acetate molecules at the rutile TiO2(110) interface with 0.1 M acetic acid have been determined with a precision of ±0.05 Å. Acetate is used as a surrogate for the carboxylate groups typically employed to anchor monocarboxylate dye molecules to TiO2 in dye-sensitized solar cells (DSSC). Structural analysis reveals small domains of ordered (2 × 1) acetate molecules, with substrate atoms closer to their bulk terminated positions compared to the clean UHV surface. Acetate is found in a bidentate bridge position, binding through both oxygen atoms to two 5-fold titanium atoms such that the molecular plane is along the [001] azimuth. Density functional theory calculations provide adsorption geometries in excellent agreement with experiment. The availability of these structural data will improve the accuracy of charge transport models for DSSC. PMID:27110318

  4. Theoretical study of the NLO responses of some natural and unnatural amino acids used as probe molecules.

    PubMed

    Derrar, S N; Sekkal-Rahal, M; Derreumaux, P; Springborg, M

    2014-08-01

    The first hyperpolarizabilities β of the natural aromatic amino acids tryptophan and tyrosine have been investigated using several methods and basis sets. Some of the theoretical results obtained were compared to the only experimental hyper-Rayleigh scattering data available. The sensitivity of tryptophan to its local environment was analyzed by constructing two-dimensional potential energy plots around the dipeptide tryptophan-lysine. Static hyperpolarizabilities β(0) of the found minima were calculated by a second-order Møller-Plesset (MP2) method in combination with the 6-31+G(d) basis set. Moreover, the efficiency of tryptophan and those of a series of unnatural amino acids as endogenous probe molecules were tested by calculating the nonlinear responses of some peptides. Impressive results were obtained for the amino acid ALADAN, which shows significantly improved nonlinear performance compared to other amino acids with weak nonlinear responses. PMID:25092242

  5. Detection of Intracellular Selenol-Containing Molecules Using a Fluorescent Probe with Near-Zero Background Signal.

    PubMed

    Sun, Qi; Yang, Shu-Hou; Wu, Lei; Dong, Qing-Jian; Yang, Wen-Chao; Yang, Guang-Fu

    2016-06-01

    Selenocysteine (Sec), encoded as the 21st amino acid, is the predominant chemical form of selenium that is closely related to various human diseases. Thus, it is of high importance to identify novel probes for sensitive and selective recognition of Sec and Sec-containing proteins. Although a few probes have been reported to detect artificially introduced selenols in cells or tissues, none of them has been shown to be sensitive enough to detect endogenous selenols. We report the characterization and application of a new fluorogenic molecular probe for the detection of intracellular selenols. This probe exhibits near-zero background fluorescence but produces remarkable fluorescence enhancement upon reacting with selenols in a fast chemical reaction. It is highly specific and sensitive for intracellular selenium-containing molecules such as Sec and selenoproteins. When combined with flow cytometry, this probe is able to detect endogenous selenols in various human cancer cells. It is also able to image endogenous selenol-containing molecules in zebrafish under a fluorescence microscope. These results demonstrate that this molecular probe can function as a useful molecular tool for intracellular selenol sensing, which is valuable in the clinical diagnosis for human diseases associated with Sec-deficiency or overdose. PMID:27161304

  6. Approaching the Golden Fleece a Molecule at a Time: Biophysical Insights into Argonaute-Instructed Nucleic Acid Interactions.

    PubMed

    Herzog, Veronika A; Ameres, Stefan L

    2015-07-01

    Argonaute proteins act at the core of nucleic acid-guided interference pathways that regulate gene expression and defend organisms against foreign genetic elements in all domains of life. Here, we review recent biophysical studies on how Argonaute proteins instruct oligonucleotides in the process of target finding, binding, cleavage, and release, as measured at high spatiotemporal resolution by single-molecule approaches. In the context of previous structural, biochemical, and computational studies, a model emerges for how Argonaute proteins manipulate the thermodynamic rules for nucleic acid hybridization to convey efficiency and specificity to RNA- and DNA-guided regulatory processes. PMID:26140366

  7. Sex specific retinoic acid signaling is required for the initiation of urogenital sinus bud development.

    PubMed

    Bryant, Sarah L; Francis, Jeffrey C; Lokody, Isabel B; Wang, Hong; Risbridger, Gail P; Loveland, Kate L; Swain, Amanda

    2014-11-15

    The mammalian urogenital sinus (UGS) develops in a sex specific manner, giving rise to the prostate in the male and the sinus vagina in the embryonic female. Androgens, produced by the embryonic testis, have been shown to be crucial to this process. In this study we show that retinoic acid signaling is required for the initial stages of bud development from the male UGS. Enzymes involved in retinoic acid synthesis are expressed in the UGS mesenchyme in a sex specific manner and addition of ligand to female tissue is able to induce prostate-like bud formation in the absence of androgens, albeit at reduced potency. Functional studies in mouse organ cultures that faithfully reproduce the initiation of prostate development indicate that one of the roles of retinoic acid signaling in the male is to inhibit the expression of Inhba, which encodes the βA subunit of Activin, in the UGS mesenchyme. Through in vivo genetic analysis and culture studies we show that inhibition of Activin signaling in the female UGS leads to a similar phenotype to that of retinoic acid treatment, namely bud formation in the absence of androgens. Our data also reveals that both androgens and retinoic acid have extra independent roles to that of repressing Activin signaling in the development of the prostate during fetal stages. This study identifies a novel role for retinoic acid as a mesenchymal factor that acts together with androgens to determine the position and initiation of bud development in the male UGS epithelia. PMID:25261715

  8. Stable isotope labelling reveals that NaCl stress decreases the production of Ensifer (Sinorhizobium) arboris lipochitooligosaccharide signalling molecules.

    PubMed

    Penttinen, Petri; Räsänen, Leena A; Lortet, Gilles; Lindström, Kristina

    2013-12-01

    Ensifer (Sinorhizobium) arboris is a symbiont of salt-tolerant leguminous trees in the genera Acacia and Prosopis that are utilized in the prevention of soil erosion and desertification and in phytoremediation of salinized soil. Signalling between the plant and the rhizobia is essential for the formation of effective symbiosis that increases the success of reclaiming saline sites. We assessed the effect of salt stress on the growth and the production of lipochitooligosaccharide signalling molecules (LCOs) of S. arboris HAMBI 2361, an LCO-overproducing derivative of the S. arboris type strain HAMBI 1552. The strain tolerated NaCl up to 750 mM. To obtain both qualitative and quantitative information on the LCO production under salt stress, we devised a method where LCOs were differentially labelled by stable isotopes of nitrogen, (14)N and (15)N, and analysed by mass spectrometry. Under control conditions, the strain produced altogether 27 structural LCO variants. In 380 mM NaCl, 13 LCO variants were produced in detectable amounts, and six of these were reliably quantified, ranging from one-tenth to one-third of the non-stressed one. PMID:24256411

  9. Low Band Gap Coplanar Conjugated Molecules Featuring Dynamic Intramolecular Lewis Acid-Base Coordination.

    PubMed

    Zhu, Congzhi; Guo, Zi-Hao; Mu, Anthony U; Liu, Yi; Wheeler, Steven E; Fang, Lei

    2016-05-20

    Ladder-type conjugated molecules with a low band gap and low LUMO level were synthesized through an N-directed borylation reaction of pyrazine-derived donor-acceptor-donor precursors. The intramolecular boron-nitrogen coordination bonds played a key role in rendering the rigid and coplanar conformation of these molecules and their corresponding electronic structures. Experimental investigation and theoretical simulation revealed the dynamic nature of such coordination, which allowed for active manipulation of the optical properties of these molecules by using competing Lewis basic solvents. PMID:27096728

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

    PubMed Central

    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

  11. The cell-adhesion and signaling molecule PECAM-1 is a molecular mediator of resistance to genotoxic chemotherapy.

    PubMed

    Bergom, Carmen; Goel, Reema; Paddock, Cathy; Gao, Cunji; Newman, Debra K; Matsuyama, Shigemi; Newman, Peter J

    2006-12-01

    Defects in the regulation of apoptotic pathways have been implicated in the emergence of cancers resistant to chemotherapy-induced cell death. Identification of novel signaling molecules that influence cell survival has the potential to facilitate the development of new cancer therapies. The cell adhesion and signaling molecule, PECAM-1, is expressed in many hematopoietic and endothelial cell malignancies, and has previously been shown to suppress mitochondrial-dependent, Bax-mediated apoptosis. The ability of PECAM-1 to influence tumor cell survival following exposure to chemotherapeutic agents, however, is not known. Here we show that, when overexpressed in HEK293 and REN mesothelioma cells, PECAM-1 confers resistance to apoptosis induced by the DNA-damaging chemotherapeutic agent, etoposide. Surprisingly, PECAM-1-mediated cytoprotection was found to be largely independent of its ability to form a signaling complex with the protein-tyrosine phosphatase SHP-2, as virtually no tyrosine phosphorylation of, or SHP-2 association with, PECAM-1 could be detected after etoposide treatment. Furthermore, PECAM-1 retained its ability to protect against chemotherapy-induced apoptosis in cells with SHP-2 levels significantly reduced using SHP-2-specific siRNA, and in cells in which Erk1/2--a downstream effector of SHP-2--had been inhibited. Finally, to determine whether endogenous PECAM-1 confers resistance to chemotherapy-induced apoptosis in lymphoid malignancies and endothelial cells, we used a lentiviral vector to stably express PECAM-1-specific siRNA in the Jurkat leukemia cell line and human umbilical vein endothelial cells (HUVECs). siRNA-expressing Jurkat cells with a 70% reduction of PECAM-1 expression were significantly more sensitive to chemotherapy-induced apoptosis. HUVECs with PECAM-1 expression reduced 75% were also markedly more sensitive to chemotherapy-induced cell death. Taken together, these data demonstrate that endogenous PECAM-1 expression on lymphoid

  12. Discovery and Characterization of a Novel Small-Molecule Agonist for Medium-Chain Free Fatty Acid Receptor G Protein-Coupled Receptor 84.

    PubMed

    Zhang, Qing; Yang, Hui; Li, Jing; Xie, Xin

    2016-05-01

    G protein-coupled receptor 84 (GPR84) is a free fatty acid receptor activated by medium-chain free fatty acids with 9-14 carbons. It is expressed mainly in the immune-related tissues, such as spleen, bone marrow, and peripheral blood leukocytes. GPR84 plays significant roles in inflammatory processes and may represent a novel drug target for the treatment of immune-mediated diseases. However, the lack of potent and specific ligands for GPR84 hindered the study of its functions and the development of potential clinical applications. Here, we report the screen of 160,000 small-molecule compounds with a calcium mobilization assay using a human embryonic kidney 293 cell line stably expressing GPR84 and Gα16, and the identification of 2-(hexylthio)pyrimidine-4,6-diol (ZQ-16) as a potent and selective agonist of GPR84 with a novel structure. ZQ-16 activates several GPR84-mediated signaling pathways, including calcium mobilization, inhibition of cAMP accumulation, phosphorylation of extracellular signal-regulated protein kinase 1/2, receptor desensitization and internalization, and receptor-β-arrestin interaction. This compound may be a useful tool to study the functions of GPR84 and a potential candidate for further structural optimization. PMID:26962172

  13. Drosophila Fatty Acid Taste Signals through the PLC Pathway in Sugar-Sensing Neurons

    PubMed Central

    Masek, Pavel; Keene, Alex C.

    2013-01-01

    Taste is the primary sensory system for detecting food quality and palatability. Drosophila detects five distinct taste modalities that include sweet, bitter, salt, water, and the taste of carbonation. Of these, sweet-sensing neurons appear to have utility for the detection of nutritionally rich food while bitter-sensing neurons signal toxicity and confer repulsion. Growing evidence in mammals suggests that taste for fatty acids (FAs) signals the presence of dietary lipids and promotes feeding. While flies appear to be attracted to fatty acids, the neural basis for fatty acid detection and attraction are unclear. Here, we demonstrate that a range of FAs are detected by the fly gustatory system and elicit a robust feeding response. Flies lacking olfactory organs respond robustly to FAs, confirming that FA attraction is mediated through the gustatory system. Furthermore, flies detect FAs independent of pH, suggesting the molecular basis for FA taste is not due to acidity. We show that low and medium concentrations of FAs serve as an appetitive signal and they are detected exclusively through the same subset of neurons that sense appetitive sweet substances, including most sugars. In mammals, taste perception of sweet and bitter substances is dependent on phospholipase C (PLC) signaling in specialized taste buds. We find that flies mutant for norpA, a Drosophila ortholog of PLC, fail to respond to FAs. Intriguingly, norpA mutants respond normally to other tastants, including sucrose and yeast. The defect of norpA mutants can be rescued by selectively restoring norpA expression in sweet-sensing neurons, corroborating that FAs signal through sweet-sensing neurons, and suggesting PLC signaling in the gustatory system is specifically involved in FA taste. Taken together, these findings reveal that PLC function in Drosophila sweet-sensing neurons is a conserved molecular signaling pathway that confers attraction to fatty acids. PMID:24068941

  14. Individual bile acids have differential effects on bile acid signaling in mice

    SciTech Connect

    Song, Peizhen Rockwell, Cheryl E. Cui, Julia Yue Klaassen, Curtis D.

    2015-02-15

    Bile acids (BAs) are known to regulate BA synthesis and transport by the farnesoid X receptor in the liver (FXR-SHP) and intestine (FXR-Fgf15). However, the relative importance of individual BAs in regulating these processes is not known. Therefore, mice were fed various doses of five individual BAs, including cholic acid (CA), chenodeoxycholic acid (CDCA), deoxoycholic acid (DCA), lithocholic acid (LCA), and ursodeoxycholic acid (UDCA) in their diets at various concentrations for one week to increase the concentration of one BA in the enterohepatic circulation. The mRNA of BA synthesis and transporting genes in liver and ileum were quantified. In the liver, the mRNA of SHP, which is the prototypical target gene of FXR, increased in mice fed all concentrations of BAs. In the ileum, the mRNA of the intestinal FXR target gene Fgf15 was increased at lower doses and to a higher extent by CA and DCA than by CDCA and LCA. Cyp7a1, the rate-limiting enzyme in BA synthesis, was decreased more by CA and DCA than CDCA and LCA. Cyp8b1, the enzyme that 12-hydroxylates BAs and is thus responsible for the synthesis of CA, was decreased much more by CA and DCA than CDCA and LCA. Surprisingly, neither a decrease in the conjugated BA uptake transporter (Ntcp) nor increase in BA efflux transporter (Bsep) was observed by FXR activation, but an increase in the cholesterol efflux transporter (Abcg5/Abcg8) was observed with FXR activation. Thus in conclusion, CA and DCA are more potent FXR activators than CDCA and LCA when fed to mice, and thus they are more effective in decreasing the expression of the rate limiting gene in BA synthesis Cyp7a1 and the 12-hydroxylation of BAs Cyp8b1, and are also more effective in increasing the expression of Abcg5/Abcg8, which is responsible for biliary cholesterol excretion. However, feeding BAs do not alter the mRNA or protein levels of Ntcp or Bsep, suggesting that the uptake or efflux of BAs is not regulated by FXR at physiological and

  15. Suppression of the HPA Axis During Cholestasis Can Be Attributed to Hypothalamic Bile Acid Signaling.

    PubMed

    McMillin, Matthew; Frampton, Gabriel; Quinn, Matthew; Divan, Ali; Grant, Stephanie; Patel, Nisha; Newell-Rogers, Karen; DeMorrow, Sharon

    2015-12-01

    Suppression of the hypothalamic-pituitary-adrenal (HPA) axis has been shown to occur during cholestatic liver injury. Furthermore, we have demonstrated that in a model of cholestasis, serum bile acids gain entry into the brain via a leaky blood brain barrier and that hypothalamic bile acid content is increased. Therefore, the aim of the current study was to determine the effects of bile acid signaling on the HPA axis. The data presented show that HPA axis suppression during cholestatic liver injury, specifically circulating corticosterone levels and hypothalamic corticotropin releasing hormone (CRH) expression, can be attenuated by administration of the bile acid sequestrant cholestyramine. Secondly, treatment of hypothalamic neurons with various bile acids suppressed CRH expression and secretion in vitro. However, in vivo HPA axis suppression was only evident after the central injection of the bile acids taurocholic acid or glycochenodeoxycholic acid but not the other bile acids studied. Furthermore, we demonstrate that taurocholic acid and glycochenodeoxycholic acid are exerting their effects on hypothalamic CRH expression after their uptake through the apical sodium-dependent bile acid transporter and subsequent activation of the glucocorticoid receptor. Taken together with previous studies, our data support the hypothesis that during cholestatic liver injury, bile acids gain entry into the brain, are transported into neurons through the apical sodium-dependent bile acid transporter and can activate the glucocorticoid receptor to suppress the HPA axis. These data also lend themselves to the broader hypothesis that bile acids may act as central modulators of hypothalamic peptides that may be altered during liver disease. PMID:26431088

  16. Lobaric Acid Inhibits VCAM-1 Expression in TNF-α-Stimulated Vascular Smooth Muscle Cells via Modulation of NF-κB and MAPK Signaling Pathways.

    PubMed

    Kwon, Ii-Seul; Yim, Joung-Han; Lee, Hong-Kum; Pyo, Suhkneung

    2016-01-01

    Lichens have been known to possess multiple biological activities, including anti-proliferative and anti-inflammatory activities. Vascular cell adhesion molecule-1 (VCAM-1) may play a role in the development of atherosclerosis. Hence, VCAM-1 is a possible therapeutic target in the treatment of the inflammatory disease. However, the effect of lobaric acid on VCAM-1 has not yet been investigated and characterized. For this study, we examined the effect of lobaric acid on the inhibition of VCAM-1 in tumor necrosis factor-alpha (TNF-α)-stimulated mouse vascular smooth muscle cells. Western blot and ELISA showed that the increased expression of VCAM-1 by TNF-α was significantly suppressed by the pre-treatment of lobaric acid (0.1-10 μg/ml) for 2 h. Lobaric acid abrogated TNF-α-induced NF-κB activity through preventing the degradation of IκB and phosphorylation of extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinases (JNK), and p38 mitogen activated protein (MAP) kinase. Lobaric acid also inhibited the expression of TNF-α receptor 1 (TNF-R1). Overall, our results suggest that lobaric acid inhibited VCAM-1 expression through the inhibition of p38, ERK, JNK and NF-κB signaling pathways, and downregulation of TNF-R1 expression. Therefore, it is implicated that lobaric acid may suppress inflammation by altering the physiology of the atherosclerotic lesion. PMID:26759698

  17. Lobaric Acid Inhibits VCAM-1 Expression in TNF-α-Stimulated Vascular Smooth Muscle Cells via Modulation of NF-κB and MAPK Signaling Pathways

    PubMed Central

    Kwon, Ii-Seul; Yim, Joung-Han; Lee, Hong-Kum; Pyo, Suhkneung

    2016-01-01

    Lichens have been known to possess multiple biological activities, including anti-proliferative and anti-inflammatory activities. Vascular cell adhesion molecule-1 (VCAM-1) may play a role in the development of atherosclerosis. Hence, VCAM-1 is a possible therapeutic target in the treatment of the inflammatory disease. However, the effect of lobaric acid on VCAM-1 has not yet been investigated and characterized. For this study, we examined the effect of lobaric acid on the inhibition of VCAM-1 in tumor necrosis factor-alpha (TNF-α)-stimulated mouse vascular smooth muscle cells. Western blot and ELISA showed that the increased expression of VCAM-1 by TNF-α was significantly suppressed by the pre-treatment of lobaric acid (0.1–10 μg/ml) for 2 h. Lobaric acid abrogated TNF-α-induced NF-κB activity through preventing the degradation of IκB and phosphorylation of extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinases (JNK), and p38 mitogen activated protein (MAP) kinase. Lobaric acid also inhibited the expression of TNF-α receptor 1 (TNF-R1). Overall, our results suggest that lobaric acid inhibited VCAM-1 expression through the inhibition of p38, ERK, JNK and NF-κB signaling pathways, and downregulation of TNF-R1 expression. Therefore, it is implicated that lobaric acid may suppress inflammation by altering the physiology of the atherosclerotic lesion. PMID:26759698

  18. Backbone 1H, 13C, and 15N assignments for the tandem ubiquitin binding domains of signal transducing adapter molecule 1.

    PubMed

    Lim, Jongsoo; Hong, Yoon-Hun; Lee, Bong-Jin; Ahn, Hee-Chul

    2011-04-01

    Signal transducing adapter molecule (STAM) forms the endosomal sorting complex required for transport-0 (ESCRT-0) complex with hepatocyte growth factor-regulated substrate (Hrs) to sort the ubiquitinated cargo proteins from the early endosomes to the ESCRT-1 complex. ESCRT-0 complex, STAM and Hrs, contains multiple ubiquitin binding domains, in which STAM has two ubiquitin binding domains, Vps27/Hrs/Stam (VHS) and ubiquitin interacting motif (UIM) at its N-terminus. By the cooperation of the multiple ubiquitin binding domains, the ESCRT-0 complex recognizes poly-ubiquitin, especially Lys63-linked ubiquitin. Here, we report the backbone resonance assignments and the secondary structure of the N-terminal 191 amino acids of the human STAM1 which includes the VHS domain and UIM. The {(1)H}-(15)N heteronuclear NOE experiments revealed that an unstructured and flexible loop region connects the VHS domain and UIM. Our work provides the basic information for the further NMR investigation of the interaction between STAM1 and poly-ubiquitin. PMID:20927613

  19. Acetic Acid Acts as a Volatile Signal To Stimulate Bacterial Biofilm Formation

    PubMed Central

    Chen, Yun; Gozzi, Kevin; Yan, Fang

    2015-01-01

    ABSTRACT Volatiles are small air-transmittable chemicals with diverse biological activities. In this study, we showed that volatiles produced by the bacterium Bacillus subtilis had a profound effect on biofilm formation of neighboring B. subtilis cells that grew in proximity but were physically separated. We further demonstrated that one such volatile, acetic acid, is particularly potent in stimulating biofilm formation. Multiple lines of genetic evidence based on B. subtilis mutants that are defective in either acetic acid production or transportation suggest that B. subtilis uses acetic acid as a metabolic signal to coordinate the timing of biofilm formation. Lastly, we investigated how B. subtilis cells sense and respond to acetic acid in regulating biofilm formation. We showed the possible involvement of three sets of genes (ywbHG, ysbAB, and yxaKC), all encoding putative holin-antiholin-like proteins, in cells responding to acetic acid and stimulating biofilm formation. All three sets of genes were induced by acetate. A mutant with a triple mutation of those genes showed a severe delay in biofilm formation, whereas a strain overexpressing ywbHG showed early and robust biofilm formation. Results of our studies suggest that B. subtilis and possibly other bacteria use acetic acid as a metabolic signal to regulate biofilm formation as well as a quorum-sensing-like airborne signal to coordinate the timing of biofilm formation by physically separated cells in the community. PMID:26060272

  20. β3GnT2 Maintains Adenylyl Cyclase-3 Signaling and Axon Guidance Molecule Expression in the Olfactory Epithelium

    PubMed Central

    Faden, Ashley A.; Knott, Thomas K.

    2011-01-01

    In the olfactory epithelium (OE), odorant receptor stimulation generates cAMP signals that function in both odor detection and the regulation of axon guidance molecule expression. The enzyme that synthesizes cAMP, adenylyl cyclase 3 (AC3), is coexpressed in olfactory sensory neurons (OSNs) with poly-N-acetyllactosamine (PLN) oligosaccharides determined by the glycosyltransferase β3GnT2. The loss of either enzyme results in similar defects in olfactory bulb (OB) innervation and OSN survival, suggesting that glycosylation may be important for AC3 function. We show here that AC3 is extensively modified with N-linked PLN, which is essential for AC3 activity and localization. On Western blots, AC3 from the wild-type OE migrates diffusely as a heavily glycosylated 200 kDa band that interacts with the PLN-binding lectin LEA. AC3 from the β3GnT2−/− OE loses these PLN modifications, migrating instead as a 140 kDa glycoprotein. Furthermore, basal and forskolin-stimulated cAMP production is reduced 80–90% in the β3GnT2−/− OE. Although AC3 traffics normally to null OSN cilia, it is absent from axon projections that aberrantly target the OB. The cAMP-dependent guidance receptor neuropilin-1 is also lost from β3GnT2−/− OSNs and axons, while semaphorin-3A ligand expression is upregulated. In addition, kirrel2, a mosaically expressed adhesion molecule that functions in axon sorting, is absent from β3GnT2−/− OB projections. These results demonstrate that PLN glycans are essential in OSNs for proper AC3 localization and function. We propose that the loss of cAMP-dependent guidance cues is also a critical factor in the severe axon guidance defects observed in β3GnT2−/− mice. PMID:21525298

  1. CSK Controls Retinoic Acid Receptor (RAR) Signaling: a RAR-c-SRC Signaling Axis Is Required for Neuritogenic Differentiation▿

    PubMed Central

    Dey, Nandini; De, Pradip K.; Wang, Mu; Zhang, Hongying; Dobrota, Erika A.; Robertson, Kent A.; Durden, Donald L.

    2007-01-01

    Herein, we report the first evidence that c-SRC is required for retinoic acid (RA) receptor (RAR) signaling, an observation that suggests a new paradigm for this family of nuclear hormone receptors. We observed that CSK negatively regulates RAR functions required for neuritogenic differentiation. CSK overexpression inhibited RA-mediated neurite outgrowth, a result which correlated with the inhibition of the SFK c-SRC. Consistent with an extranuclear effect of CSK on RAR signaling and neurite outgrowth, CSK overexpression blocked the downstream activation of RAC1. The conversion of GDP-RAC1 to GTP-RAC1 parallels the activation of c-SRC as early as 15 min following all-trans-retinoic acid treatment in LA-N-5 cells. The cytoplasmic colocalization of c-SRC and RARγ was confirmed by immunofluorescence staining and confocal microscopy. A direct and ligand-dependent binding of RAR with SRC was observed by surface plasmon resonance, and coimmunoprecipitation studies confirmed the in vivo binding of RARγ to c-SRC. Deletion of a proline-rich domain within RARγ abrogated this interaction in vivo. CSK blocked the RAR-RA-dependent activation of SRC and neurite outgrowth in LA-N-5 cells. The results suggest that transcriptional signaling events mediated by RA-RAR are necessary but not sufficient to mediate complex differentiation in neuronal cells. We have elucidated a nongenomic extranuclear signal mediated by the RAR-SRC interaction that is negatively regulated by CSK and is required for RA-induced neuronal differentiation. PMID:17325034

  2. NMDA receptor subunits and associated signaling molecules mediating antidepressant-related effects of NMDA-GluN2B antagonism

    PubMed Central

    Kiselycznyk, Carly; Jury, Nicholas; Halladay, Lindsay; Nakazawa, Kazu; Mishina, Masayoshi; Sprengel, Rolf; Grant, Seth G.N.; Svenningsson, Per; Holmes, Andrew

    2015-01-01

    Drugs targeting the glutamate N-methyl-D-aspartate receptor (NMDAR) may be efficacious for treating mood disorders, as exemplified by the rapid antidepressant effects produced by single administration of the NMDAR antagonist ketamine. Though the precise mechanisms underlying the antidepressant-related effects of NMDAR antagonism remain unclear, recent studies implicate specific NMDAR subunits, including GluN2A and GluN2B, as well as the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor (AMPAR) subunit glutamate receptor interacting molecule, PSD-95. Here, integrating mutant and pharmacological in mice, we investigated the contribution of these subunits and molecules to antidepressant-related behaviors and the antidepressant-related effects of the GluN2B blocker, Ro 25-6981. We found that global deletion of GluA1 or PSD-95 reduced forced swim test (FST) immobility, mimicking the antidepressant-related effect produced by systemically administered Ro 25-6981 in C57BL/6J mice. Moreover, the FST antidepressant-like effects of systemic Ro 25-6981 were intact in mutants with global GluA1 deletion or GluN1 deletion in forebrain interneurons, but were absent in mutants constitutively lacking GluN2A or PSD-95. Next, we found that microinfusing Ro 25-6981 into the medial prefrontal cortex (mPFC), but not basolateral amygdala, of C57BL/6J mice was sufficient to produce an antidepressant-like effect. Together, these findings extend and refine current understanding of the mechanisms mediating antidepressant-like effects produced by NMDAR-GluN2B antagonists, and may inform the development of a novel class of medications for treating depression that target the GluN2B subtype of NMDAR. PMID:25800971

  3. Ciliary subcellular localization of TGR5 determines the cholangiocyte functional response to bile acid signaling

    PubMed Central

    Masyuk, Anatoliy I.; Huang, Bing Q.; Radtke, Brynn N.; Gajdos, Gabriella B.; Splinter, Patrick L.; Masyuk, Tatyana V.; Gradilone, Sergio A.

    2013-01-01

    TGR5, the G protein-coupled bile acid receptor that transmits bile acid signaling into a cell functional response via the intracellular cAMP signaling pathway, is expressed in human and rodent cholangiocytes. However, detailed information on the localization and function of cholangiocyte TGR5 is limited. We demonstrated that in human (H69 cells) and rat cholangiocytes, TGR5 is localized to multiple, diverse subcellular compartments, with its strongest expression on the apical plasma, ciliary, and nuclear membranes. To evaluate the relationship between ciliary TGR5 and the cholangiocyte functional response to bile acid signaling, we used a model of ciliated and nonciliated H69 cells and demonstrated that TGR5 agonists induce opposite changes in cAMP and ERK levels in cells with and without primary cilia. The cAMP level was increased in nonciliated cholangiocytes but decreased in ciliated cells. In contrast, ERK signaling was induced in ciliated cholangiocytes but suppressed in cells without cilia. TGR5 agonists inhibited proliferation of ciliated cholangiocytes but activated proliferation of nonciliated cells. The observed differential effects of TGR5 agonists were associated with the coupling of TGR5 to Gαi protein in ciliated cells and Gαs protein in nonciliated cholangiocytes. The functional responses of nonciliated and ciliated cholangiocytes to TGR5-mediated bile acid signaling may have important pathophysiological significance in cilia-related liver disorders (i.e., cholangiociliopathies), such as polycystic liver disease. In summary, TGR5 is expressed on diverse cholangiocyte compartments, including a primary cilium, and its ciliary localization determines the cholangiocyte functional response to bile acid signaling. PMID:23578785

  4. Ciliary subcellular localization of TGR5 determines the cholangiocyte functional response to bile acid signaling.

    PubMed

    Masyuk, Anatoliy I; Huang, Bing Q; Radtke, Brynn N; Gajdos, Gabriella B; Splinter, Patrick L; Masyuk, Tatyana V; Gradilone, Sergio A; LaRusso, Nicholas F

    2013-06-01

    TGR5, the G protein-coupled bile acid receptor that transmits bile acid signaling into a cell functional response via the intracellular cAMP signaling pathway, is expressed in human and rodent cholangiocytes. However, detailed information on the localization and function of cholangiocyte TGR5 is limited. We demonstrated that in human (H69 cells) and rat cholangiocytes, TGR5 is localized to multiple, diverse subcellular compartments, with its strongest expression on the apical plasma, ciliary, and nuclear membranes. To evaluate the relationship between ciliary TGR5 and the cholangiocyte functional response to bile acid signaling, we used a model of ciliated and nonciliated H69 cells and demonstrated that TGR5 agonists induce opposite changes in cAMP and ERK levels in cells with and without primary cilia. The cAMP level was increased in nonciliated cholangiocytes but decreased in ciliated cells. In contrast, ERK signaling was induced in ciliated cholangiocytes but suppressed in cells without cilia. TGR5 agonists inhibited proliferation of ciliated cholangiocytes but activated proliferation of nonciliated cells. The observed differential effects of TGR5 agonists were associated with the coupling of TGR5 to Gαi protein in ciliated cells and Gαs protein in nonciliated cholangiocytes. The functional responses of nonciliated and ciliated cholangiocytes to TGR5-mediated bile acid signaling may have important pathophysiological significance in cilia-related liver disorders (i.e., cholangiociliopathies), such as polycystic liver disease. In summary, TGR5 is expressed on diverse cholangiocyte compartments, including a primary cilium, and its ciliary localization determines the cholangiocyte functional response to bile acid signaling. PMID:23578785

  5. Signaling through retinoic acid receptors in cardiac development: Doing the right things at the right times.

    PubMed

    Xavier-Neto, José; Sousa Costa, Ângela M; Figueira, Ana Carolina M; Caiaffa, Carlo Donato; Amaral, Fabio Neves do; Peres, Lara Maldanis Cerqueira; da Silva, Bárbara Santos Pires; Santos, Luana Nunes; Moise, Alexander R; Castillo, Hozana Andrade

    2015-02-01

    Retinoic acid (RA) is a terpenoid that is synthesized from vitamin A/retinol (ROL) and binds to the nuclear receptors retinoic acid receptor (RAR)/retinoid X receptor (RXR) to control multiple developmental processes in vertebrates. The available clinical and experimental data provide uncontested evidence for the pleiotropic roles of RA signaling in development of multiple embryonic structures and organs such eyes, central nervous system, gonads, lungs and heart. The development of any of these above-mentioned embryonic organ systems can be effectively utilized to showcase the many strategies utilized by RA signaling. However, it is very likely that the strategies employed to transfer RA signals during cardiac development comprise the majority of the relevant and sophisticated ways through which retinoid signals can be conveyed in a complex biological system. Here, we provide the reader with arguments indicating that RA signaling is exquisitely regulated according to specific phases of cardiac development and that RA signaling itself is one of the major regulators of the timing of cardiac morphogenesis and differentiation. We will focus on the role of signaling by RA receptors (RARs) in early phases of heart development. This article is part of a Special Issue entitled: Nuclear receptors in animal development. PMID:25134739

  6. SIGNALLING THROUGH RETINOIC ACID RECEPTORS IN CARDIAC DEVELOPMENT: DOING THE RIGHT THINGS AT THE RIGHT TIMES

    PubMed Central

    Xavier-Neto, José; Costa, Ângela M. Sousa; Figueira, Ana Carolina M.; Caiaffa, Carlo Donato; do Amaral, Fabio Neves; Peres, Lara Maldanis Cerqueira; da Silva, Bárbara Santos Pires; Santos, Luana Nunes; Moise, Alexander R.; Castillo, Hozana Andrade

    2015-01-01

    Retinoic acid (RA) is a terpenoid that is synthesized from Vitamin A/retinol (ROL) and binds to the nuclear receptors retinoic acid receptor (RAR)/retinoid X receptor (RXR) to control multiple developmental processes in vertebrates. The available clinic and experimental data provide uncontested evidence for the pleiotropic roles of RA signalling in development of multiple embryonic structures and organs such eyes, central nervous system, gonads, lungs and heart. The development of any of these above-mentioned embryonic organ systems can be effectively utilized to showcase the many strategies utilized by RA signalling. However, it is very likely that the strategies employed to transfer RA signals during cardiac development comprise the majority of the relevant and sophisticated ways through which retinoid signals can be conveyed in a complex biological system. Here, we provide the reader with arguments indicating that RA signalling is exquisitely regulated according to specific phases of cardiac development and that RA signalling itself is one of the major regulators of the timing of cardiac morphogenesis and differentiation. We will focus on the role of signalling by RA receptors (RARs) in early phases of heart development. PMID:25134739

  7. Dual small-molecule targeting of SMAD signaling stimulates human induced pluripotent stem cells toward neural lineages.

    PubMed

    Wattanapanitch, Methichit; Klincumhom, Nuttha; Potirat, Porntip; Amornpisutt, Rattaya; Lorthongpanich, Chanchao; U-pratya, Yaowalak; Laowtammathron, Chuti; Kheolamai, Pakpoom; Poungvarin, Niphon; Issaragrisil, Surapol

    2014-01-01

    Incurable neurological disorders such as Parkinson's disease (PD), Huntington's disease (HD), and Alzheimer's disease (AD) are very common and can be life-threatening because of their progressive disease symptoms with limited treatment options. To provide an alternative renewable cell source for cell-based transplantation and as study models for neurological diseases, we generated induced pluripotent stem cells (iPSCs) from human dermal fibroblasts (HDFs) and then differentiated them into neural progenitor cells (NPCs) and mature neurons by dual SMAD signaling inhibitors. Reprogramming efficiency was improved by supplementing the histone deacethylase inhibitor, valproic acid (VPA), and inhibitor of p160-Rho associated coiled-coil kinase (ROCK), Y-27632, after retroviral transduction. We obtained a number of iPS colonies that shared similar characteristics with human embryonic stem cells in terms of their morphology, cell surface antigens, pluripotency-associated gene and protein expressions as well as their in vitro and in vivo differentiation potentials. After treatment with Noggin and SB431542, inhibitors of the SMAD signaling pathway, HDF-iPSCs demonstrated rapid and efficient differentiation into neural lineages. Six days after neural induction, neuroepithelial cells (NEPCs) were observed in the adherent monolayer culture, which had the ability to differentiate further into NPCs and neurons, as characterized by their morphology and the expression of neuron-specific transcripts and proteins. We propose that our study may be applied to generate neurological disease patient-specific iPSCs allowing better understanding of disease pathogenesis and drug sensitivity assays. PMID:25207966

  8. ENHANCED DISEASE SUSCEPTIBILITY 1 and SALICYLIC ACID act redundantly to regulate resistance gene-mediated signaling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Resistance (R) protein–associated pathways are well known to participate in defense against a variety of microbial pathogens. Salicylic acid (SA) and its associated proteinaceous signaling components, including enhanced disease susceptibility 1 (EDS1), non–race-specific disease resistance 1 (NDR1), ...

  9. SALICYLIC ACID- AND NITRIC OXIDE-MEDIATED SIGNAL TRANSDUCTION IN DISEASE RESISTANCE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current advances in plant defense signaling is discussed, with emphasis on the role of nitric oxide and salicylic acid in the development of disease resistance. Nitric Oxide has recently been shown to have an important role in plant disease resistance. We show an increase in NOS-like activity in TMV...

  10. Branched-chain amino acids in metabolic signaling and insulin resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Branched-chain amino acids (BCAAs) are important directly- and indirectly-acting nutrient signals. Frequently, their actions have been reported to be anti-obesity in nature, especially in rodent models. Yet, circulating BCAAs tend to be elevated in obesity, and even associated with poorer metaboli...

  11. Cyclic GMP signaling in cardiomyocytes modulates fatty acid trafficking and prevents triglyceride accumulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    While the balance between carbohydrates and fatty acids for energy production appears to be crucial for cardiac homeostasis, much remains to be learned about the molecular mechanisms underlying this relationship. Given the reported benefits of cGMP signaling on the myocardium, we investigated the im...

  12. Platelet endothelial cell adhesion molecule-1 (PECAM-1) inhibits low density lipoprotein-induced signaling in platelets.

    PubMed

    Relou, Ingrid A M; Gorter, Gertie; Ferreira, Irlando Andrade; van Rijn, Herman J M; Akkerman, Jan-Willem N

    2003-08-29

    At physiological concentrations, low density lipoprotein (LDL) increases the sensitivity of platelets to aggregation- and secretion-inducing agents without acting as an independent activator of platelet functions. LDL sensitizes platelets by inducing a transient activation of p38MAPK, a Ser/Thr kinase that is activated by the simultaneous phosphorylation of Thr180 and Tyr182 and is an upstream regulator of cytosolic phospholipase A2 (cPLA2). A similar transient phosphorylation of p38MAPK is induced by a peptide mimicking amino acids 3359-3369 in apoB100 called the B-site. Here we report that the transient nature of p38MAPK activation is caused by platelet endothelial cell adhesion molecule 1 (PECAM-1), a receptor with an immunoreceptor tyrosine-based inhibitory motif. PECAM-1 activation by cross-linking induces tyrosine phosphorylation of PECAM-1 and a fall in phosphorylated p38MAPK and cPLA2. Interestingly, LDL and the B-site peptide also induce tyrosine phosphorylation of PECAM-1, and studies with immunoprecipitates indicate the involvement of c-Src. Inhibition of the Ser/Thr phosphatases PP1/PP2A (okadaic acid) makes the transient p38MAPK activation by LDL and the B-site peptide persistent. Inhibition of Tyr-phosphatases (vanadate) increases Tyr-phosphorylated PECAM-1 and blocks the activation of p38MAPK. Together, these findings suggest that, following a first phase in which LDL, through its B-site, phosphorylates and thereby activates p38MAPK, a second phase is initiated in which LDL activates PECAM-1 and induces dephosphorylation of p38MAPK via activation of the Ser/Thr phosphatases PP1/PP2A. PMID:12775720

  13. Dendritic Cell Expression of the Signaling Molecule TRAF6 is Critical for Gut Microbiota-Dependent Immune Tolerance

    PubMed Central

    Han, Daehee; Walsh, Matthew C.; Cejas, Pedro J.; Dang, Nicholas N.; Kim, Youngmi F.; Kim, Jihyun; Charrier-Hisamuddin, Laetitia; Chau, Lillian; Zhang, Qin; Bittinger, Kyle; Bushman, Frederic D.; Turka, Laurence A.; Shen, Hao; Reizis, Boris; DeFranco, Anthony L.; Wu, Gary D.; Choi, Yongwon

    2013-01-01

    SUMMARY The intracellular signaling molecule TRAF6 is critical for Toll-like receptor (TLR)-mediated activation of dendritic cells (DCs). We now report that DC-specific deletion of TRAF6 (TRAF6ΔDC) resulted, unexpectedly, in loss of mucosal tolerance, characterized by spontaneous development of T helper 2 (Th2) cells in the lamina propria, and eosinophilic enteritis and fibrosis in the small intestine. Loss of tolerance required the presence of gut commensal microbiota, but was independent of DC-expressed MyD88. Further, TRAF6ΔDC mice exhibited decreased regulatory T (Treg) cell numbers in the small intestine, and diminished induction of iTreg cells in response to model antigen. Evidence suggested this defect was associated with diminished DC expression of interleukin-2 (IL-2). Finally, we demonstrate that aberrant Th2 cell-associated responses in TRAF6ΔDC mice could be mitigated via restoration of Treg cell activity. Collectively, our findings reveal a role for TRAF6 in directing DC maintenance of intestinal immune tolerance through balanced induction of Treg versus Th2 cell immunity. PMID:23791643

  14. Structure and thermodynamics of effector molecule binding to the nitrogen signal transduction PII protein GlnZ from Azospirillum brasilense.

    PubMed

    Truan, Daphné; Bjelić, Saša; Li, Xiao-Dan; Winkler, Fritz K

    2014-07-29

    The trimeric PII signal transduction proteins regulate the function of a variety of target proteins predominantly involved in nitrogen metabolism. ATP, ADP and 2-oxoglutarate (2-OG) are key effector molecules influencing PII binding to targets. Studies of PII proteins have established that the 20-residue T-loop plays a central role in effector sensing and target binding. However, the specific effects of effector binding on T-loop conformation have remained poorly documented. We present eight crystal structures of the Azospirillum brasilense PII protein GlnZ, six of which are cocrystallized and liganded with ADP or ATP. We find that interaction with the diphosphate moiety of bound ADP constrains the N-terminal part of the T-loop in a characteristic way that is maintained in ADP-promoted complexes with target proteins. In contrast, the interactions with the triphosphate moiety in ATP complexes are much more variable and no single predominant interaction mode is apparent except for the ternary MgATP/2-OG complex. These conclusions can be extended to most investigated PII proteins of the GlnB/GlnK subfamily. Unlike reported for other PII proteins, microcalorimetry reveals no cooperativity between the three binding sites of GlnZ trimers for any of the three effectors under carefully controlled experimental conditions. PMID:24846646

  15. Does 2-phosphoglycolate serve as an internal signal molecule of inorganic carbon deprivation in the cyanobacterium Synechocystis sp. PCC 6803?

    PubMed

    Haimovich-Dayan, Maya; Lieman-Hurwitz, Judy; Orf, Isabel; Hagemann, Martin; Kaplan, Aaron

    2015-05-01

    Cyanobacteria possess CO2 -concentrating mechanisms (CCM) that functionally compensate for the poor affinity of their ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) to CO2 . It was proposed that 2-phosphoglycolate (2PG), produced by the oxygenase activity of Rubisco and metabolized via photorespiratory routes, serves as a signal molecule for the induction of CCM-related genes under limiting CO2 level (LC) conditions. However, in vivo evidence is still missing. Since 2PG does not permeate the cells, we manipulated its internal concentration. Four putative phosphoglycolate phosphatases (PGPases) encoding genes (slr0458, sll1349, slr0586 and slr1762) were identified in the cyanobacterium Synechocystis PCC 6803. Expression of slr0458 in Escherichia coli led to a significant rise in PGPase activity. A Synechocystis mutant overexpressing (OE) slr0458 was constructed. Compared with the wild type (WT), the mutant grew slower under limiting CO2 concentration and the intracellular 2PG level was considerably smaller than in the wild type, the transcript abundance of LC-induced genes including cmpA, sbtA and ndhF3 was reduced, and the OE cells acclimated slower to LC - indicated by the delayed rise in the apparent photosynthetic affinity to inorganic carbon. Data obtained here implicated 2PG in the acclimation of this cyanobacterium to LC but also indicated that other, yet to be identified components, are involved. PMID:25297829

  16. Oncolytic Activity of a Recombinant Measles Virus, Blind to Signaling Lymphocyte Activation Molecule, Against Colorectal Cancer Cells

    PubMed Central

    Amagai, Yosuke; Fujiyuki, Tomoko; Yoneda, Misako; Shoji, Koichiro; Furukawa, Yoichi; Sato, Hiroki; Kai, Chieko

    2016-01-01

    Oncolytic virotherapy is a distinctive antitumor therapy based on the cancer-cell-specific infectivity and killing activity of viruses, which exert a considerable antitumor effect with only a few treatments. Because colorectal cancer cells often acquire resistance to the molecular-targeted therapies and alternative treatments are called for, in this study, we evaluated the oncolytic activity against colorectal cancer cells of a recombinant measles virus (rMV-SLAMblind), which is blind to signaling lymphocytic activation molecule (SLAM) and infects target cells via nectin-4/poliovirus receptor-related 4 protein. We examined 10 cell lines including 8 cell lines that were resistant to epidermal-growth-factor-receptor (EGFR) targeted therapy. rMV-SLAMblind infected and lysed the nectin-4-positive cell lines dependently on nectin-4 expression, in spite of mutation in EGFR cascade. Tumour progression in xenograft models was also abrogated by the virus, and the infection of cancer cells in vivo by the virus was demonstrated with both flow cytometry and a histological analysis. Therefore, rMV-SLAMblind is considered a novel therapeutic agent for colorectal cancers, including those resistant to molecular-targeted therapies. PMID:27090874

  17. Oncolytic Activity of a Recombinant Measles Virus, Blind to Signaling Lymphocyte Activation Molecule, Against Colorectal Cancer Cells.

    PubMed

    Amagai, Yosuke; Fujiyuki, Tomoko; Yoneda, Misako; Shoji, Koichiro; Furukawa, Yoichi; Sato, Hiroki; Kai, Chieko

    2016-01-01

    Oncolytic virotherapy is a distinctive antitumor therapy based on the cancer-cell-specific infectivity and killing activity of viruses, which exert a considerable antitumor effect with only a few treatments. Because colorectal cancer cells often acquire resistance to the molecular-targeted therapies and alternative treatments are called for, in this study, we evaluated the oncolytic activity against colorectal cancer cells of a recombinant measles virus (rMV-SLAMblind), which is blind to signaling lymphocytic activation molecule (SLAM) and infects target cells via nectin-4/poliovirus receptor-related 4 protein. We examined 10 cell lines including 8 cell lines that were resistant to epidermal-growth-factor-receptor (EGFR) targeted therapy. rMV-SLAMblind infected and lysed the nectin-4-positive cell lines dependently on nectin-4 expression, in spite of mutation in EGFR cascade. Tumour progression in xenograft models was also abrogated by the virus, and the infection of cancer cells in vivo by the virus was demonstrated with both flow cytometry and a histological analysis. Therefore, rMV-SLAMblind is considered a novel therapeutic agent for colorectal cancers, including those resistant to molecular-targeted therapies. PMID:27090874

  18. A measles virus selectively blind to signaling lymphocytic activation molecule shows anti-tumor activity against lung cancer cells.

    PubMed

    Fujiyuki, Tomoko; Yoneda, Misako; Amagai, Yosuke; Obayashi, Kunie; Ikeda, Fusako; Shoji, Koichiro; Murakami, Yoshinori; Sato, Hiroki; Kai, Chieko

    2015-09-22

    Lung cancer cells, particularly those of non-small-cell lung cancer, are known to express Nectin-4. We previously generated a recombinant measles virus that uses Nectin-4 as its receptor but cannot bind its original principal receptor, signaling lymphocyte activation molecule (SLAM). This virus (rMV-SLAMblind) infects and kills breast cancer cells in vitro and in a subcutaneous xenograft model. However, it has yet to be determined whether rMV-SLAMblind is effective against other cancer types and in other tumor models that more closely represent disease. In this study, we analyzed the anti-tumor activity of this virus towards lung cancer cells using a modified variant that encodes green fluorescent protein (rMV-EGFP-SLAMblind). We found that rMV-EGFP-SLAMblind efficiently infected nine, human, lung cancer cell lines, and its infection resulted in reduced cell viability of six cell lines. Administration of the virus into subcutaneous tumors of xenotransplanted mice suppressed tumor growth. In addition, rMV-EGFP-SLAMblind could target scattered tumor masses grown in the lungs of xenotransplanted mice. These results suggest that rMV-SLAMblind is oncolytic for lung cancer and that it represents a promising tool for the treatment of this disease. PMID:26317644

  19. Identification of Quorum-Sensing Signal Molecules and a Biosynthetic Gene in Alicycliphilus sp. Isolated from Activated Sludge.

    PubMed

    Morohoshi, Tomohiro; Okutsu, Noriya; Xie, Xiaonan; Ikeda, Tsukasa

    2016-01-01

    Activated sludge is a complicated mixture of various microorganisms that is used to treat sewage and industrial wastewater. Many bacteria produce N-acylhomoserine lactone (AHL) as a quorum-sensing signal molecule to regulate the expression of the exoenzymes used for wastewater treatment. Here, we isolated an AHL-producing bacteria from an activated sludge sample collected from an electronic component factory, which we named Alicycliphilus sp. B1. Clone library analysis revealed that Alicycliphilus was a subdominant genus in this sample. When we screened the activated sludge sample for AHL-producing strains, 12 of 14 the AHL-producing isolates were assigned to the genus Alicycliphilus. A putative AHL-synthase gene, ALISP_0667, was cloned from the genome of B1 and transformed into Escherichia coli DH5α. The AHLs were extracted from the culture supernatants of the B1 strain and E. coli DH5α cells harboring the ALISP_0667 gene and were identified by liquid chromatography-mass spectrometry as N-(3-hydroxydecanoyl)-l-homoserine lactone and N-(3-hydroxydodecanoyl)-l-homoserine lactone. The results of comparative genomic analysis suggested that the quorum-sensing genes in the B1 strain might have been acquired by horizontal gene transfer within activated sludge. PMID:27490553

  20. Production and NMR signal optimization of hyperpolarized 13C-labeled amino acids

    NASA Astrophysics Data System (ADS)

    Parish, Christopher; Niedbalski, Peter; Ferguson, Sarah; Kiswandhi, Andhika; Lumata, Lloyd

    Amino acids are targeted nutrients for consumption by cancers to sustain their rapid growth and proliferation. 13C-enriched amino acids are important metabolic tracers for cancer diagnostics using nuclear magnetic resonance (NMR) spectroscopy. Despite this diagnostic potential, 13C NMR of amino acids however is hampered by the inherently low NMR sensitivity of the 13C nuclei. In this work, we have employed a physics technique known as dynamic nuclear polarization (DNP) to enhance the NMR signals of 13C-enriched amino acids. DNP works by transferring the high polarization of electrons to the nuclear spins via microwave irradiation at low temperature and high magnetic field. Using a fast dissolution method in which the frozen polarized samples are dissolved rapidly with superheated water, injectable solutions of 13C-amino acids with highly enhanced NMR signals (by at least 5,000-fold) were produced at room temperature. Factors that affect the NMR signal enhancement levels such as the choice of free radical polarizing agents and sample preparation will be discussed along with the thermal mixing physics model of DNP. The authors would like to acknowledge the support by US Dept of Defense Award No. W81XWH-14-1-0048 and Robert A. Welch Foundation Grant No. AT-1877.

  1. Serotonin modulates Arabidopsis root growth via changes in reactive oxygen species and jasmonic acid-ethylene signaling.

    PubMed

    Pelagio-Flores, Ramón; Ruiz-Herrera, León Francisco; López-Bucio, José

    2016-09-01

    Serotonin (5-hydroxytryptamine) is a bioactive indoleamine with neurotransmitter function in vertebrates, which represents an emerging signaling molecule in plants, playing key roles in the development and defense. In this study, the role of reactive oxygen species (ROS) and jasmonic acid (JA)-ethylene (Et) signaling in root developmental alterations induced by serotonin was investigated. An Arabidopsis thaliana mutant defective at the RADICAL-INDUCED CELL DEATH1 (RCD1) locus was resistant to paraquat-induced ROS accumulation in primary roots and showed decreased inhibition or root growth in response to serotonin. A suite of JA- and Et-related mutants including coronatine insensitive1, jasmonic acid resistant1 (jar1), etr1, ein2 and ein3 showed tolerance to serotonin in the inhibition of primary root growth and ROS redistribution within the root tip when compared with wild-type (WT) seedlings. Competence assays between serotonin and AgNO3 , a well-known blocker of Et action, showed that primary root growth in medium supplemented with serotonin was normalized by AgNO3 , whereas roots of eto3, an Et overproducer mutant, were oversensitive to serotonin. Comparison of ROS levels in WT, etr1, jar1 and rcd1 primary root tips using the ROS-specific probe 2',7'-dichlorofluorescein diacetate and confocal imaging showed that serotonin inhibition of primary root growth likely occurs independently of its conversion into melatonin. Our results provide compelling evidence that serotonin affects ROS distribution in roots, involving RCD1 and components of the JA-Et signaling pathways. PMID:26864878

  2. Fatty acid-induced NLRP3-PYCARD inflammasome activation interferes with insulin signaling

    PubMed Central

    Wen, Haitao; Gris, Denis; Lei, Yu; Jha, Sushmita; Zhang, Lu; Huang, Max Tze-Han; Brickey, Willie June; Ting, Jenny P.-Y.

    2014-01-01

    High-fat diet (HFD) and inflammation are key contributors to insulin resistance and type 2 diabetes (T2D). Interleukin (IL)-1β plays a role in insulin resistance; yet, how IL-1β is induced by fatty acid with HFD, and how this alters insulin signaling is unclear. We show that the saturated fatty acid, palmitate, but not unsaturated oleate, induces the activation of NLRP3-PYCARD inflammasome, causing caspase-1, IL-1β, and IL-18 production. This involves mitochondrial reactive oxygen species and the AMP-activated protein kinase and ULK1 autophagy signaling cascade. Inflammasome activation in hematopoietic cells impairs insulin signaling in several target tissues to reduce glucose tolerance and insulin sensitivity. Furthermore, IL-1β affects insulin sensitivity via TNF-independent and dependent pathways. These findings provide insights into the association of inflammation, diet and T2D. PMID:21478880

  3. Exogenous Modulation of Retinoic Acid Signaling Affects Adult RGC Survival in the Frog Visual System after Optic Nerve Injury.

    PubMed

    Duprey-Díaz, Mildred V; Blagburn, Jonathan M; Blanco, Rosa E

    2016-01-01

    After lesions to the mammalian optic nerve, the great majority of retinal ganglion cells (RGCs) die before their axons have even had a chance to regenerate. Frog RGCs, on the other hand, suffer only an approximately 50% cell loss, and we have previously investigated the mechanisms by which the application of growth factors can increase their survival rate. Retinoic acid (RA) is a vitamin A-derived lipophilic molecule that plays major roles during development of the nervous system. The RA signaling pathway is also present in parts of the adult nervous system, and components of it are upregulated after injury in peripheral nerves but not in the CNS. Here we investigate whether RA signaling affects long-term RGC survival at 6 weeks after axotomy. Intraocular injection of all-trans retinoic acid (ATRA), the retinoic acid receptor (RAR) type-α agonist AM80, the RARβ agonist CD2314, or the RARγ agonist CD1530, returned axotomized RGC numbers to almost normal levels. On the other hand, inhibition of RA synthesis with disulfiram, or of RAR receptors with the pan-RAR antagonist Ro-41-5253, or the RARβ antagonist LE135E, greatly reduced the survival of the axotomized neurons. Axotomy elicited a strong activation of the MAPK, STAT3 and AKT pathways; this activation was prevented by disulfiram or by RAR antagonists. Finally, addition of exogenous ATRA stimulated the activation of the first two of these pathways. Future experiments will investigate whether these strong survival-promoting effects of RA are mediated via the upregulation of neurotrophins. PMID:27611191

  4. Effect of Varying Magnetic Fields on Targeted Gene Delivery of Nucleic Acid-Based Molecules.

    PubMed

    Oral, Ozlem; Cıkım, Taha; Zuvin, Merve; Unal, Ozlem; Yagci-Acar, Havva; Gozuacik, Devrim; Koşar, Ali

    2015-11-01

    Several physical methods have been developed to introduce nucleic acid expression vectors into mammalian cells. Magnetic transfection (magnetofection) is one such transfection method, and it involves binding of nucleic acids such as DNA, RNA or siRNA to magnetic nanoparticles followed by subsequent exposure to external magnetic fields. However, the challenge between high efficiency of nucleic acid uptake by cells and toxicity was not totally resolved. Delivery of nucleic acids and their transport to the target cells require carefully designed and controlled systems. In this study, we introduced a novel magnetic system design providing varying magnet turn speeds and magnetic field directions. The system was tested in the magnetofection of human breast (MCF-7), prostate (DU-145, PC-3) and bladder (RT-4) cancer cell lines using green fluorescent protein DNA as a reporter. Polyethylenimine coated superparamagnetic iron oxide nanoparticles (SPIONs) were used as nucleic acid carriers. Adsorption of PEI on SPION improved the cytocompatibility dramatically. Application of external magnetic field increased intracellular uptake of nanoparticles and transfection efficiency without any additional cytotoxicity. We introduce our novel magnetism-based method as a promising tool for enhanced nucleic acid delivery into mammalian cells. PMID:25963582

  5. The role of Zic transcription factors in regulating hindbrain retinoic acid signaling

    PubMed Central

    2013-01-01

    Background The reiterated architecture of cranial motor neurons aligns with the segmented structure of the embryonic vertebrate hindbrain. Anterior-posterior identity of cranial motor neurons depends, in part, on retinoic acid signaling levels. The early vertebrate embryo maintains a balance between retinoic acid synthetic and degradative zones on the basis of reciprocal expression domains of the retinoic acid synthesis gene aldhehyde dehydrogenase 1a2 (aldh1a2) posteriorly and the oxidative gene cytochrome p450 type 26a1 (cyp26a1) in the forebrain, midbrain, and anterior hindbrain. Results This manuscript investigates the role of zinc finger of the cerebellum (zic) transcription factors in regulating levels of retinoic acid and differentiation of cranial motor neurons. Depletion of zebrafish Zic2a and Zic2b results in a strong downregulation of aldh1a2 expression and a concomitant reduction in activity of a retinoid-dependent transgene. The vagal motor neuron phenotype caused by loss of Zic2a/2b mimics a depletion of Aldh1a2 and is rescued by exogenously supplied retinoic acid. Conclusion Zic transcription factors function in patterning hindbrain motor neurons through their regulation of embryonic retinoic acid signaling. PMID:23937294

  6. Lipoic acid: energy metabolism and redox regulation of transcription and cell signaling

    PubMed Central

    Packer, Lester; Cadenas, Enrique

    2011-01-01

    The role of R-α-lipoic acid as a cofactor (lipoyllysine) in mitochondrial energy metabolism is well established. Lipoic acid non-covalently bound and exogenously administered to cells or supplemented in the diet is a potent modulator of the cell’s redox status. The diversity of beneficial effects of lipoic acid in a variety of tissues can be mechanistically viewed in terms of thiol/disulfide exchange reactions that modulate the environment’s redox and energy status. Lipoic acid-driven thiol/disulfide exchange reactions appear critical for the modulation of proteins involved in cell signaling and transcription factors. This review emphasizes the effects of lipoic acid on PI3K and AMPK signaling and related transcriptional pathways that are integrated by PGC-1α, a critical regulator of energy homoestasis. The effects of lipoic acid on the neuronal energy-redox axis are largely reviewed in terms of their outcomes for aging and age-related neurodegenerative diseases. PMID:21297908

  7. The Arabidopsis MAP kinase kinase 7: A crosstalk point between Auxin signaling and defense responses?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant-pathogen interaction induces a complex host response that coordinates various signaling pathways through multiple signal molecules. Besides the well-documented signal molecules salicylic acid (SA), ethylene and jasmonic acid, auxin is emerging as an important player in this response. We recent...

  8. TGF-β-SMAD3 signaling mediates hepatic bile acid and phospholipid metabolism following lithocholic acid-induced liver injury.

    PubMed

    Matsubara, Tsutomu; Tanaka, Naoki; Sato, Misako; Kang, Dong Wook; Krausz, Kristopher W; Flanders, Kathleen C; Ikeda, Kazuo; Luecke, Hans; Wakefield, Lalage M; Gonzalez, Frank J

    2012-12-01

    Transforming growth factor-β (TGFβ) is activated as a result of liver injury, such as cholestasis. However, its influence on endogenous metabolism is not known. This study demonstrated that TGFβ regulates hepatic phospholipid and bile acid homeostasis through MAD homolog 3 (SMAD3) activation as revealed by lithocholic acid-induced experimental intrahepatic cholestasis. Lithocholic acid (LCA) induced expression of TGFB1 and the receptors TGFBR1 and TGFBR2 in the liver. In addition, immunohistochemistry revealed higher TGFβ expression around the portal vein after LCA exposure and diminished SMAD3 phosphorylation in hepatocytes from Smad3-null mice. Serum metabolomics indicated increased bile acids and decreased lysophosphatidylcholine (LPC) after LCA exposure. Interestingly, in Smad3-null mice, the metabolic alteration was attenuated. LCA-induced lysophosphatidylcholine acyltransferase 4 (LPCAT4) and organic solute transporter β (OSTβ) expression were markedly decreased in Smad3-null mice, whereas TGFβ induced LPCAT4 and OSTβ expression in primary mouse hepatocytes. In addition, introduction of SMAD3 enhanced the TGFβ-induced LPCAT4 and OSTβ expression in the human hepatocellular carcinoma cell line HepG2. In conclusion, considering that Smad3-null mice showed attenuated serum ALP activity, a diagnostic indicator of cholangiocyte injury, these results strongly support the view that TGFβ-SMAD3 signaling mediates an alteration in phospholipid and bile acid metabolism following hepatic inflammation with the biliary injury. PMID:23034213

  9. Chemoattraction of macrophages by secretory molecules derived from cells expressing the signal peptide of eosinophil cationic protein

    PubMed Central

    2012-01-01

    Background Eosinophil cationic protein is a clinical asthma biomarker that would be released into blood, especially gathered in bronchia. The signal peptide of eosinophil cationic protein (ECPsp) plays an important role in translocating ECP to the extracellular space. We previously reported that ECPsp inhibits microbial growth and regulates the expression of mammalian genes encoding tumor growth factor-α (TGF-α) and epidermal growth factor receptor (EGFR). Results In the present study, we first generated a DNA microarray dataset, which showed that ECPsp upregulated proinflammatory molecules, including chemokines, interferon-induced molecules, and Toll-like receptors. The levels of mRNAs encoding CCL5, CXCL10, CXCL11, CXCL16, STAT1, and STAT2 were increased in the presence of ECPsp by 2.07-, 4.21-, 7.52-, 2.6-, 3.58-, and 1.67-fold, respectively. We then constructed a functional linkage network by integrating the microarray dataset with the pathway database of Kyoto Encyclopedia of Genes and Genomes (KEGG). Follow-up analysis revealed that STAT1 and STAT2, important transcriptional factors that regulate cytokine expression and release, served as hubs to connect the pathways of cytokine stimulation (TGF-α and EGFR pathways) and inflammatory responses. Furthermore, integrating TGF-α and EGFR with the functional linkage network indicated that STAT1 and STAT2 served as hubs that connect two functional clusters, including (1) cell proliferation and survival, and (2) inflammation. Finally, we found that conditioned medium in which cells that express ECPsp had been cultured could chemoattract macrophages. Experimentally, we also demonstrated that the migration of macrophage could be inhibited by the individual treatment of siRNAs of STAT1 or STAT2. Therefore, we hypothesize that ECPsp may function as a regulator for enhancing the migration of macrophages through the upregualtion of the transcriptional factors STAT1 and STAT2. Conclusion The increased expression and

  10. The pharmacology and therapeutic potential of small molecule inhibitors of acid-sensing ion channels in stroke intervention

    PubMed Central

    Leng, Tian-dong; Xiong, Zhi-gang

    2013-01-01

    In the nervous system, a decrease in extracellular pH is a common feature of various physiological and pathological processes, including synaptic transmission, cerebral ischemia, epilepsy, brain trauma, and tissue inflammation. Acid-sensing ion channels (ASICs) are proton-gated cation channels that are distributed throughout the central and peripheral nervous systems. Following the recent identification of ASICs as critical acid-sensing extracellular proton receptors, growing evidence has suggested that the activation of ASICs plays important roles in physiological processes such as nociception, mechanosensation, synaptic plasticity, learning and memory. However, the over-activation of ASICs is also linked to adverse outcomes for certain pathological processes, such as brain ischemia and multiple sclerosis. Based on the well-demonstrated role of ASIC1a activation in acidosis-mediated brain injury, small molecule inhibitors of ASIC1a may represent novel therapeutic agents for the treatment of neurological disorders, such as stroke. PMID:22820909

  11. A maize calcium-dependent protein kinase gene, ZmCPK4, positively regulated abscisic acid signaling and enhanced drought stress tolerance in transgenic Arabidopsis.

    PubMed

    Jiang, Shanshan; Zhang, Dan; Wang, Li; Pan, Jiaowen; Liu, Yang; Kong, Xiangpei; Zhou, Yan; Li, Dequan

    2013-10-01

    Calcium-dependent protein kinases (CDPKs) play essential roles in calcium-mediated signal transductions in plant response to abiotic stress. Several members have been identified to be regulators for plants response to abscisic acid (ABA) signaling. Here, we isolated a subgroup I CDPK gene, ZmCPK4, from maize. Quantitative real time PCR (qRT-PCR) analysis revealed that the ZmCPK4 transcripts were induced by various stresses and signal molecules. Transient and stable expression of the ZmCPK4-GFP fusion proteins revealed ZmCPK4 localized to the membrane. Moreover, overexpression of ZmCPK4 in the transgenic Arabidopsis enhanced ABA sensitivity in seed germination, seedling growth and stomatal movement. The transgenic plants also enhanced drought stress tolerance. Taken together, the results suggest that ZmCPK4 might be involved in ABA-mediated regulation of stomatal closure in response to drought stress. PMID:23911729

  12. Oxylipin Signaling: A Distinct Role for the Jasmonic Acid Precursor cis-(+)-12-Oxo-Phytodienoic Acid (cis-OPDA)

    PubMed Central

    Dave, Anuja; Graham, Ian A.

    2012-01-01

    Oxylipins are lipid-derived compounds, many of which act as signals in the plant response to biotic and abiotic stress. They include the phytohormone jasmonic acid (JA) and related jasmonate metabolites cis-(+)-12-oxo-phytodienoic acid (cis-OPDA), methyl jasmonate, and jasmonoyl-L-isoleucine (JA-Ile). Besides the defense response, jasmonates are involved in plant growth and development and regulate a range of processes including glandular trichome development, reproduction, root growth, and senescence. cis-OPDA is known to possess a signaling role distinct from JA-Ile. The non-enzymatically derived phytoprostanes are structurally similar to cis-OPDA and induce a common set of genes that are not responsive to JA in Arabidopsis thaliana. A novel role for cis-OPDA in seed germination regulation has recently been uncovered based on evidence from double mutants and feeding experiments showing that cis-OPDA interacts with abscisic acid (ABA), inhibits seed germination, and increases ABA INSENSITIVE5 (ABI5) protein abundance. Large amounts of cis-OPDA are esterified to galactolipids in A. thaliana and the resulting compounds, known as Arabidopsides, are thought to act as a rapidly available source of cis-OPDA. PMID:22645585

  13. Microbial production of bi-functional molecules by diversification of the fatty acid pathway.

    PubMed

    Garg, Shivani; Rizhsky, Ludmila; Jin, Huanan; Yu, Xiaochen; Jing, Fuyuan; Yandeau-Nelson, Marna D; Nikolau, Basil J

    2016-05-01

    Fatty acids that are chemically functionalized at their ω-ends are rare in nature yet offer unique chemical and physical properties with wide ranging industrial applications as feedstocks for bio-based polymers, lubricants and surfactants. Two enzymatic determinants control this ω-group functionality, the availability of an appropriate acyl-CoA substrate for initiating fatty acid biosynthesis, and a fatty acid synthase (FAS) variant that can accommodate that substrate in the initial condensation reaction of the process. In Type II FAS, 3-ketoacyl-ACP synthase III (KASIII) catalyses this initial condensation reaction. We characterized KASIIIs from diverse bacterial sources, and identified variants with novel substrate specificities towards atypical acyl-CoA substrates, including 3-hydroxybutyryl-CoA. Using Alicyclobacillus acidocaldarius KASIII, we demonstrate the in vivo diversion of FAS to produce novel ω-1 hydroxy-branched fatty acids from glucose in two bioengineered microbial hosts. This study unveils the biocatalytic potential of KASIII for synthesizing diverse ω-functionalized fatty acids. PMID:26827988

  14. Peptide nucleic acids rather than RNA may have been the first genetic molecule

    NASA Technical Reports Server (NTRS)

    Nelson, K. E.; Levy, M.; Miller, S. L.

    2000-01-01

    Numerous problems exist with the current thinking of RNA as the first genetic material. No plausible prebiotic processes have yet been demonstrated to produce the nucleosides or nucleotides or for efficient two-way nonenzymatic replication. Peptide nucleic acid (PNA) is a promising precursor to RNA, consisting of N-(2-aminoethyl)glycine (AEG) and the adenine, uracil, guanine, and cytosine-N-acetic acids. However, PNA has not yet been demonstrated to be prebiotic. We show here that AEG is produced directly in electric discharge reactions from CH(4), N(2), NH(3), and H(2)O. Electric discharges also produce ethylenediamine, as do NH(4)CN polymerizations. AEG is produced from the robust Strecker synthesis with ethylenediamine. The NH(4)CN polymerization in the presence of glycine leads to the adenine and guanine-N(9)-acetic acids, and the cytosine and uracil-N(1)-acetic acids are produced in high yield from the reaction of cyanoacetaldehyde with hydantoic acid, rather than urea. Preliminary experiments suggest that AEG may polymerize rapidly at 100 degrees C to give the polypeptide backbone of PNA. The ease of synthesis of the components of PNA and possibility of polymerization of AEG reinforce the possibility that PNA may have been the first genetic material.

  15. Branched-chain amino acid supplementation: impact on signaling and relevance to critical illness.

    PubMed

    Mattick, John S A; Kamisoglu, Kubra; Ierapetritou, Marianthi G; Androulakis, Ioannis P; Berthiaume, Francois

    2013-01-01

    The changes that occur in mammalian systems following trauma and sepsis, termed systemic inflammatory response syndrome, elicit major changes in carbohydrate, protein, and energy metabolism. When these events persist for too long they result in a severe depletion of lean body mass, multiple organ dysfunction, and eventually death. Nutritional supplementation has been investigated to offset the severe loss of protein, and recent evidence suggests that diets enriched in branched-chain amino acids (BCAAs) may be especially beneficial. BCAAs are metabolized in two major steps that are differentially expressed in muscle and liver. In muscle, BCAAs are reversibly transaminated to the corresponding α-keto acids. For the complete degradation of BCAAs, the α-keto acids must travel to the liver to undergo oxidation. The liver, in contrast to muscle, does not significantly express the branched-chain aminotransferase. Thus, BCAA degradation is under the joint control of both liver and muscle. Recent evidence suggests that in liver, BCAAs may perform signaling functions, more specifically via activation of mTOR (mammalian target of rapamycin) signaling pathway, influencing a wide variety of metabolic and synthetic functions, including protein translation, insulin signaling, and oxidative stress following severe injury and infection. However, understanding of the system-wide effects of BCAAs that integrate both metabolic and signaling aspects is currently lacking. Further investigation in this respect will help rationalize the design and optimization of nutritional supplements containing BCAAs for critically ill patients. PMID:23554299

  16. Phospholipase D Signaling Pathways and Phosphatidic Acid as Therapeutic Targets in Cancer

    PubMed Central

    Bruntz, Ronald C.; Lindsley, Craig W.

    2014-01-01

    Phospholipase D is a ubiquitous class of enzymes that generates phosphatidic acid as an intracellular signaling species. The phospholipase D superfamily plays a central role in a variety of functions in prokaryotes, viruses, yeast, fungi, plants, and eukaryotic species. In mammalian cells, the pathways modulating catalytic activity involve a variety of cellular signaling components, including G protein–coupled receptors, receptor tyrosine kinases, polyphosphatidylinositol lipids, Ras/Rho/ADP-ribosylation factor GTPases, and conventional isoforms of protein kinase C, among others. Recent findings have shown that phosphatidic acid generated by phospholipase D plays roles in numerous essential cellular functions, such as vesicular trafficking, exocytosis, autophagy, regulation of cellular metabolism, and tumorigenesis. Many of these cellular events are modulated by the actions of phosphatidic acid, and identification of two targets (mammalian target of rapamycin and Akt kinase) has especially highlighted a role for phospholipase D in the regulation of cellular metabolism. Phospholipase D is a regulator of intercellular signaling and metabolic pathways, particularly in cells that are under stress conditions. This review provides a comprehensive overview of the regulation of phospholipase D activity and its modulation of cellular signaling pathways and functions. PMID:25244928

  17. Cyclic dinucleotide (c-di-GMP, c-di-AMP, and cGAMP) signalings have come of age to be inhibited by small molecules.

    PubMed

    Opoku-Temeng, Clement; Zhou, Jie; Zheng, Yue; Su, Jianmei; Sintim, Herman O

    2016-08-01

    Bacteria utilize nucleotide-based second messengers to regulate a myriad of physiological processes. Cyclic dinucleotides have emerged as central regulators of bacterial physiology, controlling processes ranging from cell wall homeostasis to virulence production, and so far over thousands of manuscripts have provided biological insights into c-di-NMP signaling. The development of small molecule inhibitors of c-di-NMP signaling has significantly lagged behind. Recent developments in assays that allow for high-throughput screening of inhibitors suggest that the time is right for a concerted effort to identify inhibitors of these fascinating second messengers. Herein, we review c-di-NMP signaling and small molecules that have been developed to inhibit cyclic dinucleotide-related enzymes. PMID:27339003

  18. Dysfunction in macrophage toll-like receptor signaling caused by an inborn error of cationic amino acid transport.

    PubMed

    Kurko, Johanna; Vähä-Mäkilä, Mari; Tringham, Maaria; Tanner, Laura; Paavanen-Huhtala, Sari; Saarinen, Maiju; Näntö-Salonen, Kirsti; Simell, Olli; Niinikoski, Harri; Mykkänen, Juha

    2015-10-01

    Amino acids, especially arginine, are vital for the well-being and activity of immune cells, and disruption of amino acid balance may weaken immunity and predispose to infectious and autoimmune diseases. We present here a model of an inborn aminoaciduria, lysinuric protein intolerance (LPI), in which a single mutation in y(+)LAT1 cationic amino acid transporter gene SLC7A7 leads to a multisystem disease characterized by immunological complications, life-threatening pulmonary alveolar proteinosis and nephropathy. Macrophages are suggested to play a central role in LPI in the development of these severe secondary symptoms. We thus studied the effect of the Finnish y(+)LAT1 mutation on monocyte-derived macrophages where toll-like receptors (TLRs) act as the key molecules in innate immune response against external pathogens. The function of LPI patient and control macrophage TLR signaling was examined by stimulating the TLR2/1, TLR4 and TLR9 pathways with their associated pathogen-associated molecular patterns. Downregulation in expression of TLR9, IRF7, IRF3 and IFNB1 and in secretion of IFN-α was detected, suggesting an impaired response to TLR9 stimulation. In addition, secretion of TNF-α, IL-12 and IL-1RA by TLR2/1 stimulation and IL-12 and IL-1RA by TLR4 stimulation was increased in the LPI patients. LPI macrophages secreted significantly less nitric oxide than control macrophages, whereas plasma concentrations of inflammatory chemokines CXCL8, CXCL9 and CXCL10 were elevated in the LPI patients. In conclusion, our results strengthen the relevance of macrophages in the pathogenesis of LPI and, furthermore, suggest that cationic amino acid transport plays an important role in the regulation of innate immune responses. PMID:26210182

  19. Additive and interaction effects at three amino acid positions in HLA-DQ and HLA-DR molecules drive type 1 diabetes risk

    PubMed Central

    Hu, Xinli; Deutsch, Aaron J; Lenz, Tobias L; Onengut-Gumuscu, Suna; Han, Buhm; Chen, Wei-Min; Howson, Joanna M M; Todd, John A; de Bakker, Paul I W; Rich, Stephen S; Raychaudhuri, Soumya

    2016-01-01

    Variation in the human leukocyte antigen (HLA) genes accounts for one-half of the genetic risk in type 1 diabetes (T1D). Amino acid changes in the HLA-DR and HLA-DQ molecules mediate most of the risk, but extensive linkage disequilibrium complicates the localization of independent effects. Using 18,832 case-control samples, we localized the signal to 3 amino acid positions in HLA-DQ and HLA-DR. HLA-DQβ1 position 57 (previously known; P = 1 × 10−1,355) by itself explained 15.2% of the total phenotypic variance. Independent effects at HLA-DRβ1 positions 13 (P = 1 × 10−721) and 71 (P = 1 × 10−95) increased the proportion of variance explained to 26.9%. The three positions together explained 90% of the phenotypic variance in the HLA-DRB1–HLA-DQA1–HLA-DQB1 locus. Additionally, we observed significant interactions for 11 of 21 pairs of common HLA-DRB1–HLA-DQA1–HLA-DQB1 haplotypes (P = 1.6 × 10−64). HLA-DRβ1 positions 13 and 71 implicate the P4 pocket in the antigen-binding groove, thus pointing to another critical protein structure for T1D risk, in addition to the HLA-DQ P9 pocket. PMID:26168013

  20. Disruption of abscisic acid signaling constitutively activates Arabidopsis resistance to the necrotrophic fungus Plectosphaerella cucumerina.

    PubMed

    Sánchez-Vallet, Andrea; López, Gemma; Ramos, Brisa; Delgado-Cerezo, Magdalena; Riviere, Marie-Pierre; Llorente, Francisco; Fernández, Paula Virginia; Miedes, Eva; Estevez, José Manuel; Grant, Murray; Molina, Antonio

    2012-12-01

    Plant resistance to necrotrophic fungi is regulated by a complex set of signaling pathways that includes those mediated by the hormones salicylic acid (SA), ethylene (ET), jasmonic acid (JA), and abscisic acid (ABA). The role of ABA in plant resistance remains controversial, as positive and negative regulatory functions have been described depending on the plant-pathogen interaction analyzed. Here, we show that ABA signaling negatively regulates Arabidopsis (Arabidopsis thaliana) resistance to the necrotrophic fungus Plectosphaerella cucumerina. Arabidopsis plants impaired in ABA biosynthesis, such as the aba1-6 mutant, or in ABA signaling, like the quadruple pyr/pyl mutant (pyr1pyl1pyl2pyl4), were more resistant to P. cucumerina than wild-type plants. In contrast, the hab1-1abi1-2abi2-2 mutant impaired in three phosphatases that negatively regulate ABA signaling displayed an enhanced susceptibility phenotype to this fungus. Comparative transcriptomic analyses of aba1-6 and wild-type plants revealed that the ABA pathway negatively regulates defense genes, many of which are controlled by the SA, JA, or ET pathway. In line with these data, we found that aba1-6 resistance to P. cucumerina was partially compromised when the SA, JA, or ET pathway was disrupted in this mutant. Additionally, in the aba1-6 plants, some genes encoding cell wall-related proteins were misregulated. Fourier transform infrared spectroscopy and biochemical analyses of cell walls from aba1-6 and wild-type plants revealed significant differences in their Fourier transform infrared spectratypes and uronic acid and cellulose contents. All these data suggest that ABA signaling has a complex function in Arabidopsis basal resistance, negatively regulating SA/JA/ET-mediated resistance to necrotrophic fungi. PMID:23037505

  1. Jasmonates and Tetrahydrojasmonic Acid: A Novel Class of Anti-Aging Molecules.

    PubMed

    Alexiades, Macrene

    2016-02-01

    Jasmonates are plant-derived hormones from linoleic acid that were originally isolated from jasmine, and which are involved in plant stress regulation, wound repair and defense. They have been demonstrated through in vitro and in vivo studies to possess anti-neoplastic properties. Most recently, a novel jasmonate analog was developed, tetrahydrojasmonic acid (LR2412), which possesses favorable characteristics for cutaneous application and which induces improvements in epidermal hyaluronic acid and thickness. Clinical application of LR2412 to facial skin has been demonstrated to reduce the appearance of wrinkles and photoaging. In this issue, a clinical trial is published demonstrating the results of topical application of this agent for th cosmetic treatment of wrinkle appearance, poor texture and large pores. PMID:26885789

  2. Defense signaling among interconnected ramets of a rhizomatous clonal plant, induced by jasmonic-acid application

    NASA Astrophysics Data System (ADS)

    Chen, Jin-Song; Lei, Ning-Fei; Liu, Qing

    2011-07-01

    Resource sharing between ramets of clonal plants is a well-known phenomenon that allows stoloniferous and rhizomatous species to internally transport water, mineral nutrients and carbohydrates from sites of high supply to sites of high demand. Moreover, vascular ramet connections are likely to provide an excellent means to share substances other than resources, such as defense signals. In a greenhouse experiment, the rhizomatous sedge Carex alrofusca, consisting of integrated ramets of different ages, was used to study the transmission of defense signals through belowground rhizome connections in response to local spray with jasmonic-acid. A feeding preference test with the caterpillar Gynaephora rnenyuanensis was employed to assess benefits of rhizome connections on defense signaling. Young ramets were more responsive to jasmonic-acid treatment than middle-aged or old ramets. Condensed tannin content in the foliage of young ramets showed a significant increase and soluble carbohydrate and nitrogen content showed marginally significant decreases in the 1 mM jasmonic-acid treatment but not in control and/or 0.0001 mM jasmonic-acid treatments. The caterpillar G. rnenyuanensis preferentially grazed young ramets. After a localized spray of 1 mM jasmonic-acid, the leaf area of young ramets consumed by herbivores was greatly reduced. We propose that defense signals may be transmitted through physical connections (stolon or rhizome) among interconnected ramets of clonal plants. Induced resistance to herbivory may selectively enhance the protection of more vulnerable and valuable plant tissues and confer a significant benefit to clonal plants by a modular risk-spreading strategy, equalizing ontogenetic differences of unevenly-aged ramets in chemical defense compounds and nutritional properties of tissue.

  3. Visualising single molecules of HIV-1 and miRNA nucleic acids

    PubMed Central

    2013-01-01

    Background The scarcity of certain nucleic acid species and the small size of target sequences such as miRNA, impose a significant barrier to subcellular visualization and present a major challenge to cell biologists. Here, we offer a generic and highly sensitive visualization approach (oligo fluorescent in situ hybridization, O-FISH) that can be used to detect such nucleic acids using a single-oligonucleotide probe of 19–26 nucleotides in length. Results We used O-FISH to visualize miR146a in human and avian cells. Furthermore, we reveal the sensitivity of O-FISH detection by using a HIV-1 model system to show that as little as 1–2 copies of nucleic acids can be detected in a single cell. We were able to discern newly synthesized viral cDNA and, moreover, observed that certain HIV RNA sequences are only transiently available for O-FISH detection. Conclusions Taken together, these results suggest that the O-FISH method can potentially be used for in situ probing of, as few as, 1–2 copies of nucleic acid and, additionally, to visualize small RNA such as miRNA. We further propose that the O-FISH method could be extended to understand viral function by probing newly transcribed viral intermediates; and discern the localisation of nucleic acids of interest. Additionally, interrogating the conformation and structure of a particular nucleic acid in situ might also be possible, based on the accessibility of a target sequence. PMID:23590669

  4. The Adaptor Protein Myd88 Is a Key Signaling Molecule in the Pathogenesis of Irinotecan-Induced Intestinal Mucositis

    PubMed Central

    Wong, Deysi V. T.; Lima-Júnior, Roberto C. P.; Carvalho, Cibele B. M.; Borges, Vanessa F.; Wanderley, Carlos W. S.; Bem, Amanda X. C.; Leite, Caio A. V. G.; Teixeira, Maraiza A.; Batista, Gabriela L. P.; Silva, Rangel L.; Cunha, Thiago M.; Brito, Gerly A. C.; Almeida, Paulo R. C.; Cunha, Fernando Q.; Ribeiro, Ronaldo A.

    2015-01-01

    Intestinal mucositis is a common side effect of irinotecan-based anticancer regimens. Mucositis causes cell damage, bacterial/endotoxin translocation and production of cytokines including IL–1 and IL–18. These molecules and toll-like receptors (TLRs) activate a common signaling pathway that involves the Myeloid Differentiation adaptor protein, MyD88, whose role in intestinal mucositis is unknown. Then, we evaluated the involvement of TLRs and MyD88 in the pathogenesis of irinotecan-induced intestinal mucositis. MyD88-, TLR2- or TLR9-knockout mice and C57BL/6 (WT) mice were given either saline or irinotecan (75 mg/kg, i.p. for 4 days). On day 7, animal survival, diarrhea and bacteremia were assessed, and following euthanasia, samples of the ileum were obtained for morphometric analysis, myeloperoxidase (MPO) assay and measurement of pro-inflammatory markers. Irinotecan reduced the animal survival (50%) and induced a pronounced diarrhea, increased bacteremia, neutrophil accumulation in the intestinal tissue, intestinal damage and more than twofold increased expression of MyD88 (200%), TLR9 (400%), TRAF6 (236%), IL–1β (405%), IL–18 (365%), COX–2 (2,777%) and NF-κB (245%) in the WT animals when compared with saline-injected group (P<0.05). Genetic deletion of MyD88, TLR2 or TLR9 effectively controlled the signs of intestinal injury when compared with irinotecan-administered WT controls (P<0.05). In contrast to the MyD88-/- and TLR2-/- mice, the irinotecan-injected TLR9-/- mice showed a reduced survival, a marked diarrhea and an enhanced expression of IL–18 versus irinotecan-injected WT controls. Additionally, the expression of MyD88 was reduced in the TLR2-/- or TLR9-/- mice. This study shows a critical role of the MyD88-mediated TLR2 and TLR9 signaling in the pathogenesis of irinotecan-induced intestinal mucositis. PMID:26440613

  5. Signal transduction for taurocholic acid in the olfactory system of Atlantic salmon.

    PubMed

    Lo, Y H; Bellis, S L; Cheng, L J; Pang, J; Bradley, T M; Rhoads, D E

    1994-10-01

    Conjugated bile acids such as taurocholic acid (TChA) are potent olfactory stimuli for Atlantic salmon (Salmo salar). A plasma membrane rich fraction was derived from salmon olfactory rosettes and used to investigate TChA signal transduction and receptor binding. In the presence of GTP gamma S, TChA caused dose-dependent stimulation of phosphatidylinositol 4,5-bisphosphate (PIP2) breakdown, half maximal at less than 10(-7) M TChA. Stimulation of PIP2 breakdown by TChA required GTP gamma S, was blocked by GDP beta S, and was mimicked by A1F4-, consistent with a G protein requirement. A1F4- and Ca2+ stimulated breakdown of PIP2, but not phosphatidylcholine, arguing against a non-specific lipase activation. Stimulation of PIP2 breakdown by TChA was maximal at low Ca2+ concentration, < or = 10 nM. Conventional binding analysis with 3H-TChA was inconclusive due to a high degree of non-specific binding and to lack of tissue specificity expected for an olfactory receptor. Analysis of odorant amino acid binding indicated possible interaction of TChA with a putative acidic amino acid receptor but no interaction of TChA with a putative neutral amino acid receptor. We conclude that olfactory discrimination between amino acids and bile acids occurs in part at the receptor level while both classes of odors appear to use the same signal transduction mechanism, G protein mediated activation of phosphoinositide specific phospholipase C (PLC). PMID:7881971

  6. Visualization of retinoic acid signaling in transgenic axolotls during limb development and regeneration

    PubMed Central

    Monaghan, James R.; Maden, Malcolm

    2012-01-01

    Retinoic acid (RA) plays a necessary role in limb development and regeneration, but the precise mechanism by which it acts during these processes is unclear. The role of RA in limb regeneration was first highlighted by the remarkable effect that it has on respecifying the proximodistal axis of the regenerating limb so that serially repeated limbs are produced. To facilitate the study of RA signaling during development and then during regeneration of the same structure we have turned to the axolotl, the master of vertebrate regeneration, and generated transgenic animals that fluorescently report RA signaling in vivo. Characterization of these animals identified an anterior segment of the developing embryo where RA signaling occurs revealing conserved features of the early vertebrate embryo. During limb development RA signaling was present in the developing forelimb bud mesenchyme, but was not detected during hindlimb development. During limb regeneration, RA signaling was surprisingly almost exclusively observed in the apical epithelium suggesting a different role of RA during limb regeneration. After the addition of supplemental RA to regenerating limbs that leads to pattern duplications, the fibroblast stem cells of the blastema responded showing that they are capable of transcriptionally responding to RA. These findings are significant because it means that RA signaling may play a multifunctional role during forelimb development and regeneration and that the fibroblast stem cells that regulate proximodistal limb patterning during regeneration are targets of RA signaling. PMID:22627291

  7. The Necrotic Signal Induced by Mycophenolic Acid Overcomes Apoptosis-Resistance in Tumor Cells

    PubMed Central

    Dilhuydy, Marie-Sarah; Pinson, Benoît; Mahfouf, Walid; Pasquet, Jean-Max; Mahon, François-Xavier; Pourquier, Philippe; Moreau, Jean-François; Legembre, Patrick

    2009-01-01

    Background The amount of inosine monophosphate dehydrogenase (IMPDH), a pivotal enzyme for the biosynthesis of the guanosine tri-phosphate (GTP), is frequently increased in tumor cells. The anti-viral agent ribavirin and the immunosuppressant mycophenolic acid (MPA) are potent inhibitors of IMPDH. We recently showed that IMPDH inhibition led to a necrotic signal requiring the activation of Cdc42. Methodology/Principal Findings Herein, we strengthened the essential role played by this small GTPase in the necrotic signal by silencing Cdc42 and by the ectopic expression of a constitutive active mutant of Cdc42. Since resistance to apoptosis is an essential step for the tumorigenesis process, we next examined the effect of the MPA–mediated necrotic signal on different tumor cells demonstrating various mechanisms of resistance to apoptosis (Bcl2-, HSP70-, Lyn-, BCR-ABL–overexpressing cells). All tested cells remained sensitive to MPA–mediated necrotic signal. Furthermore, inhibition of IMPDH activity in Chronic Lymphocytic Leukemia cells was significantly more efficient at eliminating malignant cells than apoptotic inducers. Conclusions/Significance These findings indicate that necrosis and apoptosis are split signals that share few if any common hub of signaling. In addition, the necrotic signaling pathway induced by depletion of the cellular amount of GTP/GDP would be of great interest to eliminate apoptotic-resistant tumor cells. PMID:19430526

  8. Lactoferrin Combined with Retinoic Acid Stimulates B1 Cells to Express IgA Isotype and Gut-homing Molecules

    PubMed Central

    Kang, Seong-Ho; Jin, Bo-Ra; Kim, Hyeon-Jin; Seo, Goo-Young; Jang, Young-Saeng; Kim, Sun-Jin; An, Sun-Jin; Park, Seok-Rae; Kim, Woan-Sub

    2015-01-01

    It is well established that TGF-β1 and retinoic acid (RA) cause IgA isotype switching in mice. We recently found that lactoferrin (LF) also has an activity of IgA isotype switching in spleen B cells. The present study explored the effect of LF on the Ig production by mouse peritoneal B cells. LF, like TGF-β1, substantially increased IgA production in peritoneal B1 cells but little in peritoneal B2 cells. In contrast, LF increased IgG2b production in peritoneal B2 cells much more strongly than in peritoneal B1 cells. LF in combination with RA further enhanced the IgA production and, interestingly, this enhancement was restricted to IgA isotype and B1 cells. Similarly, the combination of the two molecules also led to expression of gut homing molecules α4β7 and CCR9 on peritoneal B1 cells, but not on peritoneal B2 cells. Thus, these results indicate that LF and RA can contribute to gut IgA response through stimulating IgA isotype switching and expression of gut-homing molecules in peritoneal B1 cells. PMID:25713507

  9. Coupled Cluster Evaluation of the Stability of Atmospheric Acid-Base Clusters with up to 10 Molecules.

    PubMed

    Myllys, Nanna; Elm, Jonas; Halonen, Roope; Kurtén, Theo; Vehkamäki, Hanna

    2016-02-01

    We investigate the utilization of the domain local pair natural orbital coupled cluster (DLPNO-CCSD(T)) method for calculating binding energies of atmospherical molecular clusters. Applied to small complexes of atmospherical relevance we find that the DLPNO method significantly reduces the scatter in the binding energy, which is commonly present in DFT calculations. For medium sized clusters consisting of sulfuric acid and bases the DLPNO method yields a systematic underestimation of the binding energy compared to canonical coupled cluster results. The errors in the DFT binding energies appear to be more random, while the systematic nature of the DLPNO results allows the establishment of a scaling factor, to better mimic the canonical coupled cluster calculations. Based on the trends identified for the small and medium sized systems, we further extend the application of the DLPNO method to large acid - base clusters consisting of up to 10 molecules, which have previously been out of reach with accurate coupled cluster methods. Using the Atmospheric Cluster Dynamics Code (ACDC) we compare the sulfuric acid dimer formation based on the new DLPNO binding energies with previously published RI-CC2/aug-cc-pV(T+d)Z results. We also compare the simulated sulfuric acid dimer concentration as a function of the base concentration with measurement data from the CLOUD chamber and flow tube experiments. The DLPNO method, even after scaling, underpredicts the dimer concentration significantly. Reasons for this are discussed. PMID:26771121

  10. Quantum dot targeting with lipoic acid ligase and HaloTag for single-molecule imaging on living cells.

    PubMed

    Liu, Daniel S; Phipps, William S; Loh, Ken H; Howarth, Mark; Ting, Alice Y

    2012-12-21

    We present a methodology for targeting quantum dots to specific proteins on living cells in two steps. In the first step, Escherichia coli lipoic acid ligase (LplA) site-specifically attaches 10-bromodecanoic acid onto a 13 amino acid recognition sequence that is genetically fused to a protein of interest. In the second step, quantum dots derivatized with HaloTag, a modified haloalkane dehalogenase, react with the ligated bromodecanoic acid to form a covalent adduct. We found this targeting method to be specific, fast, and fully orthogonal to a previously reported and analogous quantum dot targeting method using E. coli biotin ligase and streptavidin. We used these two methods in combination for two-color quantum dot visualization of different proteins expressed on the same cell or on neighboring cells. Both methods were also used to track single molecules of neurexin, a synaptic adhesion protein, to measure its lateral diffusion in the presence of neuroligin, its trans-synaptic adhesion partner. PMID:23181687

  11. Direct Determination of a Small-Molecule Drug, Valproic Acid, by an Electrically-Detected Microcantilever Biosensor for Personalized Diagnostics

    PubMed Central

    Huang, Long-Sun; Gunawan, Christian; Yen, Yi-Kuang; Chang, Kai-Fung

    2015-01-01

    Direct, small-molecule determination of the antiepileptic drug, valproic acid, was investigated by a label-free, nanomechanical biosensor. Valproic acid has long been used as an antiepileptic medication, which is administered through therapeutic drug monitoring and has a narrow therapeutic dosage range of 50–100 μg·mL−1 in blood or serum. Unlike labeled and clinically-used measurement techniques, the label-free, electrical detection microcantilever biosensor can be miniaturized and simplified for use in portable or hand-held point-of-care platforms or personal diagnostic tools. A micromachined microcantilever sensor was packaged into the micro-channel of a fluidic system. The measurement of the antiepileptic drug, valproic acid, in phosphate-buffered saline and serum used a single free-standing, piezoresistive microcantilever biosensor in a thermally-controlled system. The measured surface stresses showed a profile over a concentration range of 50–500 μg·mL−1, which covered the clinically therapeutic range of 50–100 μg·mL−1. The estimated limit of detection (LOD) was calculated to be 45 μg·mL−1, and the binding affinity between the drug and the antibody was measured at around 90 ± 21 μg·mL−1. Lastly, the results of the proposed device showed a similar profile in valproic acid drug detection with those of the clinically-used fluorescence polarization immunoassay. PMID:25632826

  12. MDM2 small-molecule antagonist RG7112 activates p53 signaling and regresses human tumors in preclinical cancer models.

    PubMed

    Tovar, Christian; Graves, Bradford; Packman, Kathryn; Filipovic, Zoran; Higgins, Brian; Xia, Mingxuan; Tardell, Christine; Garrido, Rosario; Lee, Edmund; Kolinsky, Kenneth; To, Kwong-Him; Linn, Michael; Podlaski, Frank; Wovkulich, Peter; Vu, Binh; Vassilev, Lyubomir T

    2013-04-15

    MDM2 negatively regulates p53 stability and many human tumors overproduce MDM2 as a mechanism to restrict p53 function. Thus, inhibitors of p53-MDM2 binding that can reactivate p53 in cancer cells may offer an effective approach for cancer therapy. RG7112 is a potent and selective member of the nutlin family of MDM2 antagonists currently in phase I clinical studies. RG7112 binds MDM2 with high affinity (K(D) ~ 11 nmol/L), blocking its interactions with p53 in vitro. A crystal structure of the RG7112-MDM2 complex revealed that the small molecule binds in the p53 pocket of MDM2, mimicking the interactions of critical p53 amino acid residues. Treatment of cancer cells expressing wild-type p53 with RG7112 activated the p53 pathway, leading to cell-cycle arrest and apoptosis. RG7112 showed potent antitumor activity against a panel of solid tumor cell lines. However, its apoptotic activity varied widely with the best response observed in osteosarcoma cells with MDM2 gene amplification. Interestingly, inhibition of caspase activity did not change the kinetics of p53-induced cell death. Oral administration of RG7112 to human xenograft-bearing mice at nontoxic concentrations caused dose-dependent changes in proliferation/apoptosis biomarkers as well as tumor inhibition and regression. Notably, RG7112 was highly synergistic with androgen deprivation in LNCaP xenograft tumors. Our findings offer a preclinical proof-of-concept that RG7112 is effective in treatment of solid tumors expressing wild-type p53. PMID:23400593

  13. IL-1 signaling modulates STAT activation to antagonize retinoic acid signaling and control Th17–iTreg balance

    PubMed Central

    Basu, Rajatava; Whitley, Sarah K.; Bhaumik, Suniti; Zindl, Carlene L.; Schoeb, Trenton R.; Benveniste, Etty N.; Pear, Warren S.; Hatton, Robin D.; Weaver, Casey T.

    2016-01-01

    Interleukin 17 (IL-17)-producing helper (TH17) and inducible regulatory CD4+ T (iTreg) cells emerge from an overlapping developmental program. In the intestines, the vitamin A metabolite retinoic acid (RA) is produced at steady state and acts as an important cofactor to induce iTreg cell development while potently inhibiting TH17 development. Here, we found that IL-1 was required to fully override RA-mediated Foxp3 expression and induce protective TH17 responses. Through induction of an NF-κB-dependent repression of SOCS3 expression, IL-1 increased the amplitude and duration of STAT3 phosphorylation induced by TH17-polarizing cytokines, leading to an altered balance of STAT3–STAT5 binding to shared consensus sequ