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1

Multiple nutritional requirements of lactobacilli: genetic lesions affecting amino acid biosynthetic pathways.  

PubMed Central

Genetic lesions responsible for amino acid requirements in several species of multiple auxotrophic lactobacilli were investigated. Systematic attempts were made to isolate mutants that could grow in the absence of each of the amino acids required by the parental strains of Lactobacillus plantarum, L. casei, L. helveticus, and L. acidophilus. After treatment with appropriate mutagens, such mutants could be obtained with respect to many but not all required amino acids. Successful isolation of mutants for a given amino acid means that a minor genetic lesion reparable by single-step mutations affects its biosynthesis; a failure to isolate mutants suggests the involvement of more extensive lesions. Analysis of these results as well as the specific requirements exhibited by the parental strains revealed certain regularities; some of the biosynthetic pathways for individual amino acids were virtually unaffected by more extensive lesions in at least species tested, whereas others were affected by more extensive lesions in at least some species. Both the number and the kind of pathways affected by extensive lesions differed appreciably among different species. Furthermore, the growth response of the parental strains to some putative amino acid precursors revealed a clear correlation between the extent of genetic lesions and the occurrence and location of a genetic block(s) for a given pathway. These findings are discussed in relation to the phylogeny, ecology, and evolution of lactic acid bacteria. PMID:6793557

Morishita, T; Deguchi, Y; Yajima, M; Sakurai, T; Yura, T

1981-01-01

2

Escape from Autologous Neutralizing Antibodies in Acute/Early Subtype C HIV-1 Infection Requires Multiple Pathways  

PubMed Central

One aim for an HIV vaccine is to elicit neutralizing antibodies (Nab) that can limit replication of genetically diverse viruses and prevent establishment of a new infection. Thus, identifying the strengths and weaknesses of Nab during the early stages of natural infection could prove useful in achieving this goal. Here we demonstrate that viral escape readily occurred despite the development of high titer autologous Nab in two subjects with acute/early subtype C infection. To provide a detailed portrayal of the escape pathways, Nab resistant variants identified at multiple time points were used to create a series of envelope (Env) glycoprotein chimeras and mutants within the background of a corresponding newly transmitted Env. In one subject, Nab escape was driven predominantly by changes in the region of gp120 that extends from the beginning of the V3 domain to the end of the V5 domain (V3V5). However, Nab escape pathways in this subject oscillated and at times required cooperation between V1V2 and the gp41 ectodomain. In the second subject, escape was driven by changes in V1V2. This V1V2-dependent escape pathway was retained over time, and its utility was reflected in the virus's ability to escape from two distinct monoclonal antibodies (Mabs) derived from this same patient via introduction of a single potential N-linked glycosylation site in V2. Spatial representation of the sequence changes in gp120 suggested that selective pressure acted upon the same regions of Env in these two subjects, even though the Env domains that drove escape were different. Together the findings argue that a single mutational pathway is not sufficient to confer escape in early subtype C HIV-1 infection, and support a model in which multiple strategies, including potential glycan shifts, direct alteration of an epitope sequence, and cooperative Env domain conformational masking, are used to evade neutralization. PMID:19763269

Rong, Rong; Li, Bing; Lynch, Rebecca M.; Haaland, Richard E.; Murphy, Megan K.; Mulenga, Joseph; Allen, Susan A.; Pinter, Abraham; Shaw, George M.; Hunter, Eric; Robinson, James E.; Gnanakaran, S.; Derdeyn, Cynthia A.

2009-01-01

3

Multiple Pathways for All Students  

ERIC Educational Resources Information Center

Maine has been focusing on the importance of postsecondary training. Maine's Skowhegan Area High School (SAHS) and Somerset Career and Technical Center (SCTC) have partnered in a Multiple Pathways initiative (funded by the Nellie Mae Education Foundation) to increase students' high school completion rate and to increase enrollment in postsecondary…

Stirling, Lee Anna

2012-01-01

4

Multiple pathways regulate shoot branching  

PubMed Central

Shoot branching patterns result from the spatio-temporal regulation of axillary bud outgrowth. Numerous endogenous, developmental and environmental factors are integrated at the bud and plant levels to determine numbers of growing shoots. Multiple pathways that converge to common integrators are most probably involved. We propose several pathways involving not only the classical hormones auxin, cytokinins and strigolactones, but also other signals with a strong influence on shoot branching such as gibberellins, sugars or molecular actors of plant phase transition. We also deal with recent findings about the molecular mechanisms and the pathway involved in the response to shade as an example of an environmental signal controlling branching. We propose the TEOSINTE BRANCHED1, CYCLOIDEA, PCF transcription factor TB1/BRC1 and the polar auxin transport stream in the stem as possible integrators of these pathways. We finally discuss how modeling can help to represent this highly dynamic system by articulating knowledges and hypothesis and calculating the phenotype properties they imply. PMID:25628627

Rameau, Catherine; Bertheloot, Jessica; Leduc, Nathalie; Andrieu, Bruno; Foucher, Fabrice; Sakr, Soulaiman

2015-01-01

5

Demonstration of differential quantitative requirements for NSF among multiple vesicle fusion pathways of GLUT4 using a dominant-negative ATPase-deficient NSF  

SciTech Connect

In this study, we investigated the relative participation of N-ethylmaleimide-sensitive factor (NSF) in vivo in a complex multistep vesicle trafficking system, the translocation response of GLUT4 to insulin in rat adipose cells. Transfections of rat adipose cells demonstrate that over-expression of wild-type NSF has no effect on total, or basal and insulin-stimulated cell-surface expression of HA-tagged GLUT4. In contrast, a dominant-negative NSF (NSF-D1EQ) can be expressed at a low enough level that it has little effect on total HA-GLUT4, but does reduce both basal and insulin-stimulated cell-surface HA-GLUT4 by {approx}50% without affecting the GLUT4 fold-translocation response to insulin. However, high expression levels of NSF-D1EQ decrease total HA-GLUT4. The inhibitory effect of NSF-D1EQ on cell-surface HA-GLUT4 is reversed when endocytosis is inhibited by co-expression of a dominant-negative dynamin (dynamin-K44A). Moreover, NSF-D1EQ does not affect cell-surface levels of constitutively recycling GLUT1 and TfR, suggesting a predominant effect of low-level NSF-D1EQ on the trafficking of GLUT4 from the endocytic recycling compared to the intracellular GLUT4-specific compartment. Thus, our data demonstrate that the multiple fusion steps in GLUT4 trafficking have differential quantitative requirements for NSF activity. This indicates that the rates of plasma and intracellular membrane fusion reactions vary, leading to differential needs for the turnover of the SNARE proteins.

Chen Xiaoli [Experimental Diabetes, Metabolism, and Nutrition Section, Diabetes Branch, NIDDK, NIH, Bethesda, MD (United States); Matsumoto, Hideko [Experimental Diabetes, Metabolism, and Nutrition Section, Diabetes Branch, NIDDK, NIH, Bethesda, MD (United States); Hinck, Cynthia S. [Experimental Diabetes, Metabolism, and Nutrition Section, Diabetes Branch, NIDDK, NIH, Bethesda, MD (United States); Al-Hasani, Hadi [Institute of Biochemistry, University of Cologne, Cologne (Germany); St-Denis, Jean-Francois [Experimental Diabetes, Metabolism, and Nutrition Section, Diabetes Branch, NIDDK, NIH, Bethesda, MD (United States); Whiteheart, Sidney W. [Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY (United States); Cushman, Samuel W. [Experimental Diabetes, Metabolism, and Nutrition Section, Diabetes Branch, NIDDK, NIH, Bethesda, MD (United States)]. E-mail: sam_cushman@nih.gov

2005-07-22

6

Beyond Tracking: Multiple Pathways to College, Career, and Civic Participation  

ERIC Educational Resources Information Center

"Beyond Tracking" responds to the a sobering assessment of American high schools by delineating and promoting an innovative and well-defined notion of multiple pathways. The book's authors clearly distinguish their use of the term "multiple pathways" from any updated version of the tracking system that marked so many American high schools during…

Oakes, Jeannie, Ed.; Saunders, Marisa, Ed.

2008-01-01

7

Development of water requirement factors for biomass conversion pathway  

Microsoft Academic Search

Published data were used to develop an integrated spreadsheet-based model to estimate total water requirement for 12 biomass conversion pathways. The water requirement for crop production was attributed only to the grains in the estimates since agricultural residues are produced irrespective of their use for fuel or electricity. Corn stover- and wheat straw-based ethanol production pathways are water efficient, requiring

Shikhar Singh; Amit Kumar

2011-01-01

8

Chemotaxis: Navigating by Multiple Signaling Pathways  

NSDL National Science Digital Library

During chemotaxis, phosphatidylinositol 3,4,5-trisphosphate (PIP3) accumulates at the leading edge of a eukaryotic cell, where it induces the formation of pseudopodia. PIP3 has been suggested to be the compass of cells navigating in gradients of signaling molecules. Recent observations suggest that chemotaxis is more complex than previously anticipated. Complete inhibition of all PIP3 signaling has little effect, and alternative pathways have been identified. In addition, selective pseudopod growth and retraction are more important in directing cell movement than is the place where new pseudopodia are formed.

Peter J. M. Van Haastert (University of Groningen; Department of Biology REV)

2007-07-24

9

Simultaneous Identification of Multiple Driver Pathways in Cancer  

PubMed Central

Distinguishing the somatic mutations responsible for cancer (driver mutations) from random, passenger mutations is a key challenge in cancer genomics. Driver mutations generally target cellular signaling and regulatory pathways consisting of multiple genes. This heterogeneity complicates the identification of driver mutations by their recurrence across samples, as different combinations of mutations in driver pathways are observed in different samples. We introduce the Multi-Dendrix algorithm for the simultaneous identification of multiple driver pathways de novo in somatic mutation data from a cohort of cancer samples. The algorithm relies on two combinatorial properties of mutations in a driver pathway: high coverage and mutual exclusivity. We derive an integer linear program that finds set of mutations exhibiting these properties. We apply Multi-Dendrix to somatic mutations from glioblastoma, breast cancer, and lung cancer samples. Multi-Dendrix identifies sets of mutations in genes that overlap with known pathways – including Rb, p53, PI(3)K, and cell cycle pathways – and also novel sets of mutually exclusive mutations, including mutations in several transcription factors or other genes involved in transcriptional regulation. These sets are discovered directly from mutation data with no prior knowledge of pathways or gene interactions. We show that Multi-Dendrix outperforms other algorithms for identifying combinations of mutations and is also orders of magnitude faster on genome-scale data. Software available at: http://compbio.cs.brown.edu/software. PMID:23717195

Leiserson, Mark D. M.; Blokh, Dima

2013-01-01

10

Multiple cholinergic signaling pathways in pituitary gonadotrophs.  

PubMed

Acetylcholine (ACh) has been established as a paracrine factor in the anterior pituitary gland, but the receptors mediating ACh action and the cell types bearing these receptors have not been identified. Our results showed that the expression of the nicotinic subunits mRNAs followed the order ?2 > ?1 = ?9 > ?4 in cultured rat pituitary cells. The expression of the subunits in immortalized L?T2 mouse gonadotrophs followed the order ?2 > ?4 = ?1. M4 > M3 muscarinic receptor mRNA were also identified in pituitary and L?T2 cells. The treatment of cultured pituitary cells with GnRH down-regulated the expression of ?9 and ?4 mRNAs, without affecting the expression of M3 and M4 receptor mRNAs, and ACh did not alter the expression of GnRH receptor mRNA. We also performed double immunostaining to show the expression of ?2-subunit and M4 receptor proteins in gonadotrophs. Functional nicotinic channels capable of generating an inward current, facilitation of electrical activity, and Ca(2+) influx were identified in single gonadotrophs and L?T2 cells. In both cell types, the M3 receptor-mediated, phospholipase C-dependent Ca(2+) mobilization activated an outward apamin-sensitive K(+) current and caused hyperpolarization. The activation of M4 receptors by ACh inhibited cAMP production and GnRH-induced LH release in a pertussis toxin-sensitive manner. We concluded that multiple cholinergic receptors are expressed in gonadotrophs and that the main secretory action of ACh is inhibitory through M4 receptor-mediated down-regulation of cAMP production. The expression of nicotinic receptors in vitro compensates for the lack of regular GnRH stimulation of gonadotrophs. PMID:23161872

Zemkova, Hana; Kucka, Marek; Bjelobaba, Ivana; Tomic, Melanija; Stojilkovic, Stanko S

2013-01-01

11

Many Sizes Fit All: Considering Multiple Pathways to Higher Learning  

ERIC Educational Resources Information Center

The need to dramatically increase the number of young people who gain the credentials and skills necessary to succeed in 21st century America has never been clearer. One of the most promising ideas for achieving this goal is to establish "multiple pathways" for learners that lead to a variety of high-quality postsecondary options. As New England…

Weisstein, Ephraim; Jacobson, David

2009-01-01

12

The Frizzled family: receptors for multiple signal transduction pathways  

Microsoft Academic Search

SUMMARY: Frizzled genes encode integral membrane proteins that function in multiple signal transduction pathways. They have been identified in diverse animals, from sponges to humans. The family is defined by conserved structural features, including seven hydrophobic domains and a cysteine-rich ligand-binding domain. Frizzled proteins are receptors for secreted Wnt proteins, as well as other ligands, and also play a critical

Hui-Chuan Huang; Peter S Klein

2004-01-01

13

PPAR? regulates multiple proinflammatory pathways to suppress atherosclerosis  

PubMed Central

Lipid homeostasis and inflammation are key determinants in atherogenesis, exemplified by the requirement of lipid-laden, foam cell macrophages for atherosclerotic lesion formation. Although the nuclear receptor PPAR? has been implicated in both systemic lipid metabolism and macrophage inflammation, its role as a therapeutic target in vascular disease is unclear. We show here that orally active PPAR? agonists significantly reduce atherosclerosis in apoE?/? mice. Metabolic and gene expression studies reveal that PPAR? attenuates lesion progression through its HDL-raising effect and anti-inflammatory activity within the vessel wall, where it suppresses chemoattractant signaling by down-regulation of chemokines. Activation of PPAR? also induces the expression of regulator of G protein signaling (RGS) genes, which are implicated in blocking the signal transduction of chemokine receptors. Consistent with this, PPAR? ligands repress monocyte transmigration and macrophage inflammatory responses elicited by atherogenic cytokines. These results reveal that PPAR? antagonizes multiple proinflammatory pathways and suggest PPAR?-selective drugs as candidate therapeutics for atherosclerosis. PMID:18337509

Barish, Grant D.; Atkins, Annette R.; Downes, Michael; Olson, Peter; Chong, Ling-Wa; Nelson, Mike; Zou, Yuhua; Hwang, Hoosang; Kang, Heonjoong; Curtiss, Linda; Evans, Ronald M.; Lee, Chih-Hao

2008-01-01

14

Drosophila Myc integrates multiple signaling pathways to regulate intestinal stem cell proliferation during midgut regeneration  

PubMed Central

Intestinal stem cells (ISCs) in the Drosophila adult midgut are essential for maintaining tissue homeostasis, and their proliferation and differentiation speed up in order to meet the demand for replenishing the lost cells in response to injury. Several signaling pathways including JAK-STAT, EGFR and Hippo (Hpo) pathways have been implicated in damage-induced ISC proliferation, but the mechanisms that integrate these pathways have remained elusive. Here, we demonstrate that the Drosophila homolog of the oncoprotein Myc (dMyc) functions downstream of these signaling pathways to mediate their effects on ISC proliferation. dMyc expression in precursor cells is stimulated in response to tissue damage, and dMyc is essential for accelerated ISC proliferation and midgut regeneration. We show that tissue damage caused by dextran sulfate sodium feeding stimulates dMyc expression via the Hpo pathway, whereas bleomycin feeding activates dMyc through the JAK-STAT and EGFR pathways. We provide evidence that dMyc expression is transcriptionally upregulated by multiple signaling pathways, which is required for optimal ISC proliferation in response to tissue damage. We have also obtained evidence that tissue damage can upregulate dMyc expression post-transcriptionally. Finally, we show that a basal level of dMyc expression is required for ISC maintenance, proliferation and lineage differentiation during normal tissue homeostasis. PMID:23896988

Ren, Fangfang; Shi, Qing; Chen, Yongbin; Jiang, Alice; Ip, Y Tony; Jiang, Huaqi; Jiang, Jin

2013-01-01

15

Ubiquitin-protein ligases in muscle wasting: multiple parallel pathways?  

NASA Technical Reports Server (NTRS)

PURPOSE OF REVIEW: Studies in a wide variety of animal models of muscle wasting have led to the concept that increased protein breakdown via the ubiquitin-proteasome pathway is responsible for the loss of muscle mass seen as muscle atrophy. The complexity of the ubiquitination apparatus has hampered our understanding of how this pathway is activated in atrophying muscles and which ubiquitin-conjugating enzymes in muscle are responsible. RECENT FINDINGS: Recent experiments have shown that two newly identified ubiquitin-protein ligases (E3s), atrogin-1/MAFbx and MURF-1, are critical in the development of muscle atrophy. Other in-vitro studies also implicated E2(14k) and E3alpha, of the N-end rule pathway, as playing an important role in the process. SUMMARY: It seems likely that multiple pathways of ubiquitin conjugation are activated in parallel in atrophying muscle, perhaps to target for degradation specific classes of muscle proteins. The emerging challenge will be to define the protein targets for, as well as inhibitors of, these E3s.

Lecker, Stewart H.; Goldberg, A. L. (Principal Investigator)

2003-01-01

16

Smoking worsens multiple sclerosis prognosis: Two different pathways are involved.  

PubMed

Smoking worsens multiple sclerosis (MS) prognosis. Our study provides evidence that indoleamine 2,3-dioxygenase activity is reduced in MS patients who smoke, leading to increased production of IL-6 and IL-13. Additionally, both degree of expression and renin-angiotensin system activity levels were increased in MS patients who smoked, inducing increase in IL-17 and IL-22-producing cell numbers as well as significantly greater production of CCL2, CCL3 and CXCL10 chemokines by monocytes. Finally, both pathways contributed to a significant decrease in the number of CD4+CD25+FoxP3+ regulatory T cells in MS patients who smoked. Both pathways could be responsible for the association between smoking and MS risk. PMID:25867464

Correale, Jorge; Farez, Mauricio F

2015-04-15

17

Axon Regeneration Requires A Conserved MAP Kinase Pathway  

PubMed Central

Regeneration of injured neurons can restore function, but most neurons regenerate poorly or not at all. The failure to regenerate in some cases is due to a lack of activation of cell-intrinsic regeneration pathways. Thus, these pathways might be targeted for the development of therapies that can restore neuron function after injury or disease. Here, we show that the DLK-1 MAP kinase pathway is essential for regeneration in C. elegans motor neurons. Loss of this pathway eliminates regeneration, while activating it improves regeneration. Further, these proteins also regulate the later step of growth cone migration. We conclude that after axon injury, activation of this MAP kinase cascade is required to switch the mature neuron from an aplastic state to a state capable of growth. PMID:19164707

Hammarlund, Marc; Nix, Paola; Hauth, Linda; Jorgensen, Erik M.; Bastiani, Michael

2009-01-01

18

Pathway-based association study of multiple candidate genes and multiple traits using structural equation models.  

PubMed

There is increasing interest in the joint analysis of multiple genetic variants from multiple genes and multiple correlated quantitative traits in association studies. The classical approach involves testing univariate associations between genotypes and phenotypes and correcting for multiple testing that results in loss of power to detect associations. In this paper, we propose modeling complex relationships between genetic variants in candidate genes and measured correlated traits using structural equation models (SEM), taking advantage of prior knowledge on clinical and genetic pathways. We adopt generalized structured component analysis (GSCA) as an approach to SEM and develop a single association test between multiple genetic variants in a gene and a set of correlated traits, taking into account all available data from other genes and other traits. The performance of this test is investigated by simulations. We apply the proposed method to the Quebec Child and Adolescent Health and Social Survey (1999) data to investigate genetic associations with cardiovascular disease-related traits. PMID:25558046

Romdhani, Hela; Hwang, Heungsun; Paradis, Gilles; Roy-Gagnon, Marie-Helene; Labbe, Aurelie

2015-02-01

19

Multiple pathway asbestos exposure assessment for a Superfund community.  

PubMed

Libby, MT, USA, was the home to workers at a historical vermiculite mining facility and served as the processing and distribution center for this industrial product that was contaminated with amphibole asbestos. Several pathways of environmental asbestos exposure to the general population have been identified. The local clinic and health screening program collects data from participants on past occupational and environmental exposures to vermiculite and asbestos. Health studies among this population have demonstrated associations between amphibole exposure and health outcomes, but critical questions regarding the nature and level of exposure associated with specific outcomes remain unanswered. The objective of this study was to develop a comprehensive exposure assessment approach that integrates information on individuals' contact frequency with multiple exposure pathways. For 3031 participants, we describe cumulative exposure metrics for environmental exposures, occupational exposures, and residents' contact with carry-home asbestos from household workers. As expected, cumulative exposures for all three occupational categories were higher among men compared with women, and cumulative exposures for household contact and environmental pathways were higher among women. The comprehensive exposure assessment strategies will advance health studies and risk assessment approaches in this population with a complex history of both occupational and environmental asbestos exposure. PMID:24756101

Noonan, Curtis W; Conway, Kathrene; Landguth, Erin L; McNew, Tracy; Linker, Laura; Pfau, Jean; Black, Brad; Szeinuk, Jaime; Flores, Raja

2015-01-01

20

Targeting Multiple Key Signaling Pathways in Melanoma using Leelamine  

PubMed Central

Melanoma is a highly drug resistant cancer with resistance developing to agents targeting single proteins. To circumvent this problem, a new class of agent inhibiting multiple key pathways important in this disease is being developed to reduce the likelihood of developing resistant disease. The PI3 kinase (PI3K), MAP kinase (MAPK) and STAT3 pathways are constitutively activated in 50–70% of melanomas promoting disease development. To identify a drug simultaneously targeting the PI3K, MAPK and STAT3 cascades, a natural product library was screened to identifying leelamine as a potential inhibitor. Leelamine was 4.5-fold more effective at inhibiting cultured melanoma cell survival than normal cells, with average IC50 values of 2 and 9.3 µmol/L, respectively. It inhibited cellular proliferation at a concentration of 2.5 µmol/L by 40–80% and longer exposure increased apoptosis 600% through a mechanism detailed in the article in the current issue of this journal by Kuzu OF et al. Leelamine inhibited the growth of preexisting xenografted melanoma tumors by an average of 60% by targeting the PI3K, MAPK and STAT3 pathways without affecting animal body weight or blood markers of major organ function. The mechanism of action of leelamine is mediated by disruption of cholesterol transport, causing decreased cellular proliferation and, consequently leading to increased tumor cell apoptosis as well as decreased tumor vascularization. Thus, a unique agent and novel mechanism of action has been identified for the treatment of melanoma that acts by inhibiting the activity of three major signaling pathways regulating the development of this disease. PMID:24688050

Gowda, Raghavendra; Madhunapantula, SubbaRao V.; Kuzu, Omer F.; Sharma, Arati; Robertson, Gavin P.

2015-01-01

21

Multiple sweet receptors and transduction pathways revealed in knockout mice by temperature dependence and gurmarin sensitivity.  

PubMed

Sweet taste transduction involves taste receptor type 1, member 2 (T1R2), taste receptor type 1, member 3 (T1R3), gustducin, and TRPM5. Because knockout (KO) mice lacking T1R3, gustducin's Galpha subunit (Galphagust), or TRPM5 exhibited greatly reduced, but not abolished responses of the chorda tympani (CT) nerve to sweet compounds, it is likely that multiple sweet transduction pathways exist. That gurmarin (Gur), a sweet taste inhibitor, inhibits some but not all mouse CT responses to sweet compounds supports the existence of multiple sweet pathways. Here, we investigated Gur inhibition of CT responses to sweet compounds as a function of temperature in KO mice lacking T1R3, Galphagust, or TRPM5. In T1R3-KO mice, responses to sucrose and glucose were Gur sensitive (GS) and displayed a temperature-dependent increase (TDI). In Galphagust-KO mice, responses to sucrose and glucose were Gur-insensitive (GI) and showed a TDI. In TRPM5-KO mice, responses to glucose were GS and showed a TDI. All three KO mice exhibited no detectable responses to SC45647, and their responses to saccharin displayed neither GS nor a TDI. For all three KO mice, the lingual application of pronase, another sweet response inhibitor, almost fully abolished responses to sucrose and glucose but did not affect responses to saccharin. These results provide evidence for 1) the existence of multiple transduction pathways underlying responses to sugars: a T1R3-independent GS pathway for sucrose and glucose, and a TRPM5-independent temperature sensitive GS pathway for glucose; 2) the requirement for Galphagust in GS sweet taste responses; and 3) the existence of a sweet independent pathway for saccharin, in mouse taste cells on the anterior tongue. PMID:19211717

Ohkuri, Tadahiro; Yasumatsu, Keiko; Horio, Nao; Jyotaki, Masafumi; Margolskee, Robert F; Ninomiya, Yuzo

2009-04-01

22

Multiple degradation pathways regulate versatile CIP/KIP CDK inhibitors  

PubMed Central

The mammalian CIP/KIP family of cyclin-dependent kinase (CDK) inhibitors (CKIs) comprises three proteins – p21Cip1/WAF1, p27Kip1, and p57Kip2 – that bind and inhibit cyclin–CDK complexes, which are key regulators of the cell cycle. CIP/KIP CKIs have additional independent functions in regulating transcription, apoptosis and actin cytoskeletal dynamics. These divergent functions are performed in distinct cellular compartments and contribute to the seemingly contradictory observation that the CKIs can both suppress and promote cancer. Multiple ubiquitin ligases (E3s) direct the proteasome-mediated degradation of p21, p27 and p57. This review analyzes recent data highlighting our current understanding of how distinct E3 pathways regulate subpopulations of the CKIs to control their diverse functions. PMID:22154077

Starostina, Natalia G.; Kipreos, Edward T.

2011-01-01

23

Multiple Pathways for Homologous Recombination in Saccharomyces Cerevisiae  

PubMed Central

The genes in the RAD52 epistasis group of Saccharomyces cerevisiae are necessary for most mitotic and meiotic recombination events. Using an intrachromosomal inverted-repeat assay, we previously demonstrated that mitotic recombination of this substrate is dependent upon the RAD52 gene. In the present study the requirement for other genes in this epistasis group for recombination of inverted repeats has been analyzed, and double and triple mutant strains were examined for their epistatic relationships. The majority of recombination events are mediated by a RAD51-dependent pathway, where the RAD54, RAD55 and RAD57 genes function downstream of RAD51. Cells mutated in RAD55 or RAD57 as well as double mutants are cold-sensitive for inverted-repeat recombination, whereas a rad51 rad55 rad57 triple mutant is not. The RAD1 gene is not required for inverted-repeat recombination but is able to process spontaneous DNA lesions to produce recombinant products in the absence of RAD51. Furthermore, there is still considerably more recombination in rad1 rad51 mutants than in rad52 mutants, indicating the presence of another, as yet unidentified, recombination pathway. PMID:7705645

Rattray, A. J.; Symington, L. S.

1995-01-01

24

Menin represses malignant phenotypes of melanoma through regulating multiple pathways  

PubMed Central

Abstract Substantial genetic evidence suggests that chromosome 11q is involved in regulating initiation and progression of malignant melanomas. Mutations of the MEN1 gene, located in chromosome 11q13, predispose individuals to the multiple endocrine neoplasia type 1 (MEN1) familial syndrome. MEN1 patients develop primary malignant melanoma, suggesting a potential link between MEN1 syndrome and development of melanomas, but the precise molecular mechanism is poorly understood. Here we show that the MEN1 gene suppresses malignant phenotypes of melanoma cells through multiple signalling pathways. Ectopic expression of menin, the product of MEN1 gene, significantly inhibited melanoma cell proliferation and migration in vitro and in vivo. The inhibition was partly achieved through suppressing expression of growth factor pleiotrophin (PTN) and receptor protein tyrosine phosphatase (RPTP) ?/?, accompanied with the reduced expression of phosphatidylinositol 3-kinase (pI3K) and decreased phosphorylation of focal adhesion kinase (FAK) and extracellular signal regulated kinase (ERK1/2). Interestingly, reduced expression of menin was associated with hypermethylation of the CpG islands of the MEN1 promoter in melanoma cells. Taken together, these findings suggest a previously unappreciated function for menin in suppressing malignant phenotypes of melanomas and unravel a novel mechanism involving in regulating PTN signalling by menin in development and progression of melanomas. PMID:21129151

Gao, Shu-Bin; Feng, Zi-Jie; Xu, Bin; Chen, Yan; Zheng, Hong-Hua; Yin, Ping; Hua, Xianxin; Jin, Guang-Hui

2011-01-01

25

Mycobacterial Esx-3 Requires Multiple Components for Iron Acquisition  

E-print Network

The type VII secretion systems are conserved across mycobacterial species and in many Gram-positive bacteria. While the well-characterized Esx-1 pathway is required for the virulence of pathogenic mycobacteria and conjugation ...

Siegrist, M. Sloan

26

Multiple Pathways to Graduation: New Routes to High School Completion. CRPE Working Paper #2010_2  

ERIC Educational Resources Information Center

Concerned about the persistently high dropout rates from big-city secondary schools, education leaders are trying a new approach to increasing the graduation rate--multiple pathways to graduation. Multiple pathways initiatives are relatively new and far from proven. Even the most advanced examples face significant issues, i.e., the need to…

Marsh, Shannon

2010-01-01

27

Sustaining multiple ecosystem functions in grassland communities requires higher biodiversity  

E-print Network

Sustaining multiple ecosystem functions in grassland communities requires higher biodiversity Erika (sent for review July 27, 2009) Society places value on the multiple functions of ecosystems from ecosystems to provide threshold levels of up to eight ecosystem functions simultaneously. Across years

Zavaleta, Erika

28

10 CFR 63.115 - Requirements for multiple barriers.  

Code of Federal Regulations, 2014 CFR

...NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN A GEOLOGIC REPOSITORY AT YUCCA MOUNTAIN, NEVADA Technical Criteria Postclosure Performance Assessment § 63.115 Requirements for multiple...

2014-01-01

29

10 CFR 63.115 - Requirements for multiple barriers.  

Code of Federal Regulations, 2010 CFR

...NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN A GEOLOGIC REPOSITORY AT YUCCA MOUNTAIN, NEVADA Technical Criteria Postclosure Performance Assessment § 63.115 Requirements for multiple...

2010-01-01

30

Why do personality traits predict divorce? Multiple pathways through satisfaction.  

PubMed

While previous studies indicate that personality traits influence the likelihood of divorce, the processes that drive this relationship have yet to be examined. Accordingly, the current study utilized a nationally representative, longitudinal sample (N = 8,206) to test whether relationship satisfaction is a pathway by which personality traits influence relationship dissolution. Specifically, we examined 2 different pathways: the enduring dynamics and emergent distress pathways. The enduring dynamics pathway specifies that the association between personality and relationship satisfaction reflects ongoing relationship dynamics, which are presumed to be stable across a relationship. In contrast, the emergent distress pathway proposes that personality leads to worsening dynamics across the course of a relationship, which is indicated by changes in satisfaction. For each pathway, we assessed actor, partner, and combined effects for the Big Five. Results replicate previous research in that personality traits prospectively predict relationship dissolution. Both the enduring dynamics and emergent distress pathways served to explain this relationship, though the enduring dynamics model evidenced the largest effects. The emergent distress pathway was stronger for couples who experienced certain life events, suggesting that personality plays a role in adapting to changing life circumstances. Moreover, results suggest that the personality of the dyad is important in this process: Above and beyond actor effects, partner effects influenced relationship functioning (although the influence of combined effects was less clear). In sum, the current study demonstrates that personality traits shape the overall quality of one's relationship, which in turn influences the likelihood of relationship dissolution. PMID:24841100

Solomon, Brittany C; Jackson, Joshua J

2014-06-01

31

Transition model for ricin-aptamer interactions with multiple pathways and energy barriers.  

PubMed

We develop a transition model to interpret single-molecule ricin-aptamer interactions with multiple unbinding pathways and energy barriers measured by atomic force microscopy dynamic force spectroscopy. Molecular simulations establish the relationship between binding conformations and the corresponding unbinding pathways. Each unbinding pathway follows a Bell-Evans multiple-barrier model. Markov-type transition matrices are developed to analyze the redistribution of unbinding events among the pathways under different loading rates. Our study provides detailed information about complex behaviors in ricin-aptamer unbinding events. PMID:25353521

Wang, Bin; Xu, Bingqian

2014-02-01

32

Transition model for ricin-aptamer interactions with multiple pathways and energy barriers  

NASA Astrophysics Data System (ADS)

We develop a transition model to interpret single-molecule ricin-aptamer interactions with multiple unbinding pathways and energy barriers measured by atomic force microscopy dynamic force spectroscopy. Molecular simulations establish the relationship between binding conformations and the corresponding unbinding pathways. Each unbinding pathway follows a Bell-Evans multiple-barrier model. Markov-type transition matrices are developed to analyze the redistribution of unbinding events among the pathways under different loading rates. Our study provides detailed information about complex behaviors in ricin-aptamer unbinding events.

Wang, Bin; Xu, Bingqian

2014-02-01

33

Requirements for innate immune pathways in environmentally induced autoimmunity  

PubMed Central

There is substantial evidence that environmental triggers in combination with genetic and stochastic factors play an important role in spontaneous autoimmune disease. Although the specific environmental agents and how they promote autoimmunity remain largely unknown, in part because of diverse etiologies, environmentally induced autoimmune models can provide insights into potential mechanisms. Studies of idiopathic and environmentally induced systemic autoimmunity show that they are mediated by common adaptive immune response genes. By contrast, although the innate immune system is indispensable for autoimmunity, there are clear differences in the molecular and cellular innate components that mediate specific systemic autoimmune diseases, suggesting distinct autoimmune-promoting pathways. Some of these differences may be related to the bifurcation of toll-like receptor signaling that distinguishes interferon regulatory factor 7-mediated type I interferon production from nuclear factor-?B-driven proinflammatory cytokine expression. Accordingly, idiopathic and pristane-induced systemic autoimmunity require both type I interferon and proinflammatory cytokines whereas the less aggressive mercury-induced autoimmunity, although dependent on nucleic acid-binding toll-like receptors, does not require type I interferon but needs proinflammatory cytokines. Scavenger receptors and the inflammasome may contribute to silica-induced autoimmunity. Greater understanding of the innate mechanisms responsible for idiopathic and environmentally induced autoimmunity should yield new information into the processes that instigate and drive systemic autoimmunity. PMID:23557436

2013-01-01

34

Retinoic Acid Activates Two Pathways Required for Meiosis in Mice  

PubMed Central

In all sexually reproducing organisms, cells of the germ line must transition from mitosis to meiosis. In mice, retinoic acid (RA), the extrinsic signal for meiotic initiation, activates transcription of Stra8, which is required for meiotic DNA replication and the subsequent processes of meiotic prophase. Here we report that RA also activates transcription of Rec8, which encodes a component of the cohesin complex that accumulates during meiotic S phase, and which is essential for chromosome synapsis and segregation. This RA induction of Rec8 occurs in parallel with the induction of Stra8, and independently of Stra8 function, and it is conserved between the sexes. Further, RA induction of Rec8, like that of Stra8, requires the germ-cell-intrinsic competence factor Dazl. Our findings strengthen the importance of RA and Dazl in the meiotic transition, provide important details about the Stra8 pathway, and open avenues to investigate early meiosis through analysis of Rec8 induction and function. PMID:25102060

Koubova, Jana; Hu, Yueh-Chiang; Bhattacharyya, Tanmoy; Soh, Y. Q. Shirleen; Gill, Mark E.; Goodheart, Mary L.; Hogarth, Cathryn A.; Griswold, Michael D.; Page, David C.

2014-01-01

35

The twin arginine protein transport pathway exports multiple virulence proteins in the plant pathogen Streptomyces scabies.  

PubMed

Summary Streptomyces scabies is one of a group of organisms that causes the economically important disease potato scab. Analysis of the S. scabies genome sequence indicates that it is likely to secrete many proteins via the twin arginine protein transport (Tat) pathway, including several proteins whose coding sequences may have been acquired through horizontal gene transfer and share a common ancestor with proteins in other plant pathogens. Inactivation of the S. scabies Tat pathway resulted in pleiotropic phenotypes including slower growth rate and increased permeability of the cell envelope. Comparison of the extracellular proteome of the wild type and DeltatatC strains identified 73 predicted secretory proteins that were present in reduced amounts in the tatC mutant strain, and 47 Tat substrates were verified using a Tat reporter assay. The DeltatatC strain was almost completely avirulent on Arabidopsis seedlings and was delayed in attaching to the root tip relative to the wild-type strain. Genes encoding 14 candidate Tat substrates were individually inactivated, and seven of these mutants were reduced in virulence compared with the wild-type strain. We conclude that the Tat pathway secretes multiple proteins that are required for full virulence. PMID:20487278

Joshi, Madhumita V; Mann, Stefan G; Antelmann, Haike; Widdick, David A; Fyans, Joanna K; Chandra, Govind; Hutchings, Matthew I; Toth, Ian; Hecker, Michael; Loria, Rosemary; Palmer, Tracy

2010-07-01

36

Passive Decomposition of Multiple Mechanical Systems under Coordination Requirements  

E-print Network

Passive Decomposition of Multiple Mechanical Systems under Coordination Requirements Dongjun Lee interacting with environments and/or humans under coordination requirements. The key innovation is the passive coordination and energetic passivity of the closed- loop system. It decomposes the system dynamics into shape

Lee, Dongjun

37

MicroRNA-17~92 plays a causative role in lymphomagenesis by coordinating multiple oncogenic pathways.  

PubMed

MicroRNAs (miRNAs) have been broadly implicated in cancer, but their exact function and mechanism in carcinogenesis remain poorly understood. Elevated miR-17~92 expression is frequently found in human cancers, mainly due to gene amplification and Myc-mediated transcriptional upregulation. Here we show that B cell-specific miR-17~92 transgenic mice developed lymphomas with high penetrance and that, conversely, Myc-driven lymphomagenesis stringently requires two intact alleles of miR-17~92. We experimentally identified miR-17~92 target genes by PAR-CLIP and validated select target genes in miR-17~92 transgenic mice. These analyses demonstrate that miR-17~92 drives lymphomagenesis by suppressing the expression of multiple negative regulators of the PI3K and NF?B pathways and by inhibiting the mitochondrial apoptosis pathway. Accordingly, miR-17~92-driven lymphoma cells exhibited constitutive activation of the PI3K and NF?B pathways and chemical inhibition of either pathway reduced tumour size and prolonged the survival of lymphoma-bearing mice. These findings establish miR-17~92 as a powerful cancer driver that coordinates the activation of multiple oncogenic pathways, and demonstrate for the first time that chemical inhibition of miRNA downstream pathways has therapeutic value in treating cancers caused by miRNA dysregulation. PMID:23921550

Jin, Hyun Yong; Oda, Hiroyo; Lai, Maoyi; Skalsky, Rebecca L; Bethel, Kelly; Shepherd, Jovan; Kang, Seung Goo; Liu, Wen-Hsien; Sabouri-Ghomi, Mohsen; Cullen, Bryan R; Rajewsky, Klaus; Xiao, Changchun

2013-08-28

38

MicroRNA-17?92 plays a causative role in lymphomagenesis by coordinating multiple oncogenic pathways  

PubMed Central

MicroRNAs (miRNAs) have been broadly implicated in cancer, but their exact function and mechanism in carcinogenesis remain poorly understood. Elevated miR-17?92 expression is frequently found in human cancers, mainly due to gene amplification and Myc-mediated transcriptional upregulation. Here we show that B cell-specific miR-17?92 transgenic mice developed lymphomas with high penetrance and that, conversely, Myc-driven lymphomagenesis stringently requires two intact alleles of miR-17?92. We experimentally identified miR-17?92 target genes by PAR-CLIP and validated select target genes in miR-17?92 transgenic mice. These analyses demonstrate that miR-17?92 drives lymphomagenesis by suppressing the expression of multiple negative regulators of the PI3K and NF?B pathways and by inhibiting the mitochondrial apoptosis pathway. Accordingly, miR-17?92-driven lymphoma cells exhibited constitutive activation of the PI3K and NF?B pathways and chemical inhibition of either pathway reduced tumour size and prolonged the survival of lymphoma-bearing mice. These findings establish miR-17?92 as a powerful cancer driver that coordinates the activation of multiple oncogenic pathways, and demonstrate for the first time that chemical inhibition of miRNA downstream pathways has therapeutic value in treating cancers caused by miRNA dysregulation. PMID:23921550

Jin, Hyun Yong; Oda, Hiroyo; Lai, Maoyi; Skalsky, Rebecca L; Bethel, Kelly; Shepherd, Jovan; Kang, Seung Goo; Liu, Wen-Hsien; Sabouri-Ghomi, Mohsen; Cullen, Bryan R; Rajewsky, Klaus; Xiao, Changchun

2013-01-01

39

Cinnamon polyphenols regulate multiple metabolic pathways involved in intestinal lipid metabolism of primary small intestinal enterocytes  

Technology Transfer Automated Retrieval System (TEKTRAN)

Increasing evidence suggests that dietary factors may affect the expression of multiple genes and signaling pathways including those that regulate intestinal lipoprotein metabolism. The small intestine is actively involved in the regulation of dietary lipid absorption, intracellular transport and me...

40

Reliable pre-eclampsia pathways based on multiple independent microarray data sets.  

PubMed

Pre-eclampsia is a multifactorial disorder characterized by heterogeneous clinical manifestations. Gene expression profiling of preeclamptic placenta have provided different and even opposite results, partly due to data compromised by various experimental artefacts. Here we aimed to identify reliable pre-eclampsia-specific pathways using multiple independent microarray data sets. Gene expression data of control and preeclamptic placentas were obtained from Gene Expression Omnibus. Single-sample gene-set enrichment analysis was performed to generate gene-set activation scores of 9707 pathways obtained from the Molecular Signatures Database. Candidate pathways were identified by t-test-based screening using data sets, GSE10588, GSE14722 and GSE25906. Additionally, recursive feature elimination was applied to arrive at a further reduced set of pathways. To assess the validity of the pre-eclampsia pathways, a statistically-validated protocol was executed using five data sets including two independent other validation data sets, GSE30186, GSE44711. Quantitative real-time PCR was performed for genes in a panel of potential pre-eclampsia pathways using placentas of 20 women with normal or severe preeclamptic singleton pregnancies (n = 10, respectively). A panel of ten pathways were found to discriminate women with pre-eclampsia from controls with high accuracy. Among these were pathways not previously associated with pre-eclampsia, such as the GABA receptor pathway, as well as pathways that have already been linked to pre-eclampsia, such as the glutathione and CDKN1C pathways. mRNA expression of GABRA3 (GABA receptor pathway), GCLC and GCLM (glutathione metabolic pathway), and CDKN1C was significantly reduced in the preeclamptic placentas. In conclusion, ten accurate and reliable pre-eclampsia pathways were identified based on multiple independent microarray data sets. A pathway-based classification may be a worthwhile approach to elucidate the pathogenesis of pre-eclampsia. PMID:25323968

Kawasaki, Kaoru; Kondoh, Eiji; Chigusa, Yoshitsugu; Ujita, Mari; Murakami, Ryusuke; Mogami, Haruta; Brown, J B; Okuno, Yasushi; Konishi, Ikuo

2015-02-01

41

Chronic itch development in sensory neurons requires BRAF signaling pathways  

PubMed Central

Chronic itch, or pruritus, is associated with a wide range of skin abnormalities. The mechanisms responsible for chronic itch induction and persistence remain unclear. We developed a mouse model in which a constitutively active form of the serine/threonine kinase BRAF was expressed in neurons gated by the sodium channel Nav1.8 (BRAFNav1.8 mice). We found that constitutive BRAF pathway activation in BRAFNav1.8 mice results in ectopic and enhanced expression of a cohort of itch-sensing genes, including gastrin-releasing peptide (GRP) and MAS-related GPCR member A3 (MRGPRA3), in nociceptors expressing transient receptor potential vanilloid 1 (TRPV1). BRAFNav1.8 mice showed de novo neuronal responsiveness to pruritogens, enhanced pruriceptor excitability, and heightened evoked and spontaneous scratching behavior. GRP receptor expression was increased in the spinal cord, indicating augmented coding capacity for itch subsequent to amplified pruriceptive inputs. Enhanced GRP expression and sustained ERK phosphorylation were observed in sensory neurons of mice with allergic contact dermatitis– or dry skin–elicited itch; however, spinal ERK activation was not required for maintaining central sensitization of itch. Inhibition of either BRAF or GRP signaling attenuated itch sensation in chronic itch mouse models. These data uncover RAF/MEK/ERK signaling as a key regulator that confers a subset of nociceptors with pruriceptive properties to initiate and maintain long-lasting itch sensation. PMID:24216512

Zhao, Zhong-Qiu; Huo, Fu-Quan; Jeffry, Joseph; Hampton, Lori; Demehri, Shadmehr; Kim, Seungil; Liu, Xian-Yu; Barry, Devin M.; Wan, Li; Liu, Zhong-Chun; Li, Hui; Turkoz, Ahu; Ma, Kaijie; Cornelius, Lynn A.; Kopan, Raphael; Battey, James F.; Zhong, Jian; Chen, Zhou-Feng

2013-01-01

42

Hedgehog Pathway Modulation by Multiple Lipid Binding Sites on the Smoothened Effector of Signal Response  

PubMed Central

Summary Hedgehog (Hh) signaling during development and in postembryonic tissues requires activation of the 7TM oncoprotein Smoothened (Smo), by mechanisms that may involve endogenous lipidic modulators. Exogenous Smo ligands previously identified include the plant sterol cyclopamine (and its therapeutically useful synthetic mimics) and hydroxylated cholesterol derivatives (oxysterols); Smo is also highly sensitive to cellular sterol levels. The relationships between these effects are unclear because the relevant Smo structural determinants are unknown. We identify the conserved extracellular cysteine rich domain (CRD) as the site of action for oxysterols on Smo, involving residues structurally analogous to those contacting the Wnt lipid adduct in the homologous Frizzled CRD; this modulatory effect is distinct from that of cyclopamine mimics, from Hh-mediated regulation, and from the permissive action of cellular sterol pools. These results imply that Hh pathway activity is sensitive to lipid binding at several Smo sites, suggesting mechanisms for tuning by multiple physiological inputs. PMID:23954590

Myers, Benjamin R.; Sever, Navdar; Chong, Yong Chun; Kim, James; Belani, Jitendra D.; Rychnovsky, Scott; Bazan, J. Fernando; Beachy, Philip A.

2014-01-01

43

Multiple roles for lipids in the Hedgehog signalling pathway  

Microsoft Academic Search

The identification of endogenous sterol derivatives that modulate the Hedgehog (Hh) signalling pathway has begun to suggest testable hypotheses for the cellular biological functions of Patched, and for the lipoprotein association of Hh. Progress in the field of intracellular sterol trafficking has emphasized how tightly the distribution of intracellular sterol is controlled, and suggests that the synthesis of sterol derivatives

Suzanne Eaton

2008-01-01

44

Molecular Evolution of Multiple-Level Control of Heme Biosynthesis Pathway in Animal Kingdom  

PubMed Central

Adaptation of enzymes in a metabolic pathway can occur not only through changes in amino acid sequences but also through variations in transcriptional activation, mRNA splicing and mRNA translation. The heme biosynthesis pathway, a linear pathway comprised of eight consecutive enzymes in animals, provides researchers with ample information for multiple types of evolutionary analyses performed with respect to the position of each enzyme in the pathway. Through bioinformatics analysis, we found that the protein-coding sequences of all enzymes in this pathway are under strong purifying selection, from cnidarians to mammals. However, loose evolutionary constraints are observed for enzymes in which self-catalysis occurs. Through comparative genomics, we found that in animals, the first intron of the enzyme-encoding genes has been co-opted for transcriptional activation of the genes in this pathway. Organisms sense the cellular content of iron, and through iron-responsive elements in the 5? untranslated regions of mRNAs and the intron-exon boundary regions of pathway genes, translational inhibition and exon choice in enzymes may be enabled, respectively. Pathway product (heme)-mediated negative feedback control can affect the transport of pathway enzymes into the mitochondria as well as the ubiquitin-mediated stability of enzymes. Remarkably, the positions of these controls on pathway activity are not ubiquitous but are biased towards the enzymes in the upstream portion of the pathway. We revealed that multiple-level controls on the activity of the heme biosynthesis pathway depend on the linear depth of the enzymes in the pathway, indicating a new strategy for discovering the molecular constraints that shape the evolution of a metabolic pathway. PMID:24489775

Tzou, Wen-Shyong; Chu, Ying; Lin, Tzung-Yi; Hu, Chin-Hwa; Pai, Tun-Wen; Liu, Hsin-Fu; Lin, Han-Jia; Cases, Ildeofonso; Rojas, Ana; Sanchez, Mayka; You, Zong-Ye; Hsu, Ming-Wei

2014-01-01

45

Molecular evolution of multiple-level control of heme biosynthesis pathway in animal kingdom.  

PubMed

Adaptation of enzymes in a metabolic pathway can occur not only through changes in amino acid sequences but also through variations in transcriptional activation, mRNA splicing and mRNA translation. The heme biosynthesis pathway, a linear pathway comprised of eight consecutive enzymes in animals, provides researchers with ample information for multiple types of evolutionary analyses performed with respect to the position of each enzyme in the pathway. Through bioinformatics analysis, we found that the protein-coding sequences of all enzymes in this pathway are under strong purifying selection, from cnidarians to mammals. However, loose evolutionary constraints are observed for enzymes in which self-catalysis occurs. Through comparative genomics, we found that in animals, the first intron of the enzyme-encoding genes has been co-opted for transcriptional activation of the genes in this pathway. Organisms sense the cellular content of iron, and through iron-responsive elements in the 5' untranslated regions of mRNAs and the intron-exon boundary regions of pathway genes, translational inhibition and exon choice in enzymes may be enabled, respectively. Pathway product (heme)-mediated negative feedback control can affect the transport of pathway enzymes into the mitochondria as well as the ubiquitin-mediated stability of enzymes. Remarkably, the positions of these controls on pathway activity are not ubiquitous but are biased towards the enzymes in the upstream portion of the pathway. We revealed that multiple-level controls on the activity of the heme biosynthesis pathway depend on the linear depth of the enzymes in the pathway, indicating a new strategy for discovering the molecular constraints that shape the evolution of a metabolic pathway. PMID:24489775

Tzou, Wen-Shyong; Chu, Ying; Lin, Tzung-Yi; Hu, Chin-Hwa; Pai, Tun-Wen; Liu, Hsin-Fu; Lin, Han-Jia; Cases, Ildeofonso; Rojas, Ana; Sanchez, Mayka; You, Zong-Ye; Hsu, Ming-Wei

2014-01-01

46

Bayesian Joint Selection of Genes and Pathways: Applications in Multiple Myeloma Genomics  

PubMed Central

It is well-established that the development of a disease, especially cancer, is a complex process that results from the joint effects of multiple genes involved in various molecular signaling pathways. In this article, we propose methods to discover genes and molecular pathways significantly associated with clinical outcomes in cancer samples. We exploit the natural hierarchal structure of genes related to a given pathway as a group of interacting genes to conduct selection of both pathways and genes. We posit the problem in a hierarchical structured variable selection (HSVS) framework to analyze the corresponding gene expression data. HSVS methods conduct simultaneous variable selection at the pathway (group level) and the gene (within-group) level. To adapt to the overlapping group structure present in the pathway–gene hierarchy of the data, we developed an overlap-HSVS method that introduces latent partial effect variables that partition the marginal effect of the covariates and corresponding weights for a proportional shrinkage of the partial effects. Combining gene expression data with prior pathway information from the KEGG databases, we identified several gene–pathway combinations that are significantly associated with clinical outcomes of multiple myeloma. Biological discoveries support this relationship for the pathways and the corresponding genes we identified. PMID:25520554

Zhang, Lin; Morris, Jeffrey S; Zhang, Jiexin; Orlowski, Robert Z; Baladandayuthapani, Veerabhadran

2014-01-01

47

Canonical and noncanonical Hedgehog pathway in the pathogenesis of multiple myeloma  

PubMed Central

The Hedgehog (Hh) pathway is required for cell-fate determination during the embryonic life, as well as cell growth and differentiation in the adult organism, where the inappropriate activation has been implicated in several cancers. Here we demonstrate that Hh signaling plays a significant role in growth and survival of multiple myeloma (MM) cells. We observed that CD138+ MM cells express Hh genes and confirmed Smoothened (Smo)–dependent Hh signaling in MM using a novel synthetic Smo inhibitor, NVP-LDE225 (Novartis), which decreased MM cell viability by inducing specific down-regulation of Gli1 and Ptch1, hallmarks of Hh activity. In addition, we detected a nuclear localization of Gli1 in MM cells, which is completely abrogated by Forskolin, a Gli1-modulating compound, confirming Smo-independent mechanisms leading to Hh activation in MM. Finally, we identified that bone marrow stromal cells are a source of the Shh ligand, although they are resistant to the Hh inhibitor because of defective Smo expression and Ptch1 up-regulation. Further in vitro as well as in vivo studies showed antitumor efficacy of NVP-LDE225 in combination with bortezomib. Altogether, our data demonstrate activation of both canonical and noncanonical Hh pathway in MM, thus providing the rationale for testing Hh inhibitors in clinical trials to improve MM patient outcome. PMID:22821765

Blotta, Simona; Jakubikova, Jana; Calimeri, Teresa; Roccaro, Aldo M.; Amodio, Nicola; Azab, Abdel Kareem; Foresta, Umberto; Mitsiades, Constantine S.; Rossi, Marco; Todoerti, Katia; Molica, Stefano; Morabito, Fortunato; Neri, Antonino; Tagliaferri, Piersandro; Tassone, Pierfrancesco; Anderson, Kenneth C.

2012-01-01

48

Multiple degradation pathways of phenanthrene by Stenotrophomonas maltophilia C6  

PubMed Central

Stenotrophomonas maltophilia strain C6, capable of utilizing phenanthrene as a sole source of carbon and energy, was isolated from creosote-contaminated sites at Hilo, Hawaii. Twenty-two metabolites of phenanthrene, covering from dihydrodiol to protocatechuic acid, were isolated and characterized. Phenanthrene was degraded via an initial dioxygenation on 1,2-, 3,4-, and 9,10-C, where the 3,4-dioxygenation and subsequent metabolisms were most dominant. The metabolic pathways were further branched by ortho- and meta-cleavage of phenanthrenediols to produce 1-hydroxy-2-naphthoic acid, 2-hydroxy-1-naphthoic acid, and naphthalene-1,2-dicarboxylic acid. These intermediates were then transformed to naphthalene-1,2-diol. 1-Hydroxy-2-naphthoic acid was also degraded via a direct ring cleavage. Naphthalene-1,2-diol underwent primarily ortho-cleavage to produce trans-2-carboxycinnamic acid and then to form phthalic acid, 4,5-dihydroxyphthalic acid and protocatechuic acid. Accumulation of salicylic acid in prolonged incubation indicated that a limited extent of meta-cleavage of naphthalene-1, 2-diol also occurred. This is the first study of detailed phenanthrene metabolic pathways by Stenotrophomonas maltophilia. PMID:23539472

Gao, Shumei; Seo, Jong-Su; Wang, Jun; Keum, Young-Soo; Li, Jianqiang; Li, Qing X.

2013-01-01

49

The genetics of multiple sclerosis: SNPs to pathways to pathogenesis  

Microsoft Academic Search

Multiple sclerosis (MS) is an autoimmune demyelinating disease and a common cause of neurological disability in young adults. The modest heritability of MS reflects complex genetic effects and multifaceted gene–environment interactions. The human leukocyte antigen (HLA) region is the strongest susceptibility locus for MS, but a genome-wide association study recently identified new susceptibility genes. Progress in high-throughput genotyping and sequencing

Sergio E. Baranzini; Stephen Sawcer; Jorge R. Oksenberg; Stephen L. Hauser

2008-01-01

50

Network-Based Identification of Biomarkers Coexpressed with Multiple Pathways  

PubMed Central

Unraveling complex molecular interactions and networks and incorporating clinical information in modeling will present a paradigm shift in molecular medicine. Embedding biological relevance via modeling molecular networks and pathways has become increasingly important for biomarker identification in cancer susceptibility and metastasis studies. Here, we give a comprehensive overview of computational methods used for biomarker identification, and provide a performance comparison of several network models used in studies of cancer susceptibility, disease progression, and prognostication. Specifically, we evaluated implication networks, Boolean networks, Bayesian networks, and Pearson’s correlation networks in constructing gene coexpression networks for identifying lung cancer diagnostic and prognostic biomarkers. The results show that implication networks, implemented in Genet package, identified sets of biomarkers that generated an accurate prediction of lung cancer risk and metastases; meanwhile, implication networks revealed more biologically relevant molecular interactions than Boolean networks, Bayesian networks, and Pearson’s correlation networks when evaluated with MSigDB database. PMID:25392692

Guo, Nancy Lan; Wan, Ying-Wooi

2014-01-01

51

Patient-Specific Pathway Analysis Using PARADIGM Identifies Key Activities in Multiple Cancers - Josh Stuart, TCGA Scientific Symposium 2011  

Cancer.gov

Home News and Events Multimedia Library Videos Patient-Specific Pathway Analysis Using PARADIGM Identifies Key Activities in Cancers - Josh Stuart Patient-Specific Pathway Analysis Using PARADIGM Identifies Key Activities in Multiple Cancers - Josh

52

Cytolethal distending toxins require components of the ER-associated degradation pathway for host cell entry.  

PubMed

Intracellular acting protein exotoxins produced by bacteria and plants are important molecular determinants that drive numerous human diseases. A subset of these toxins, the cytolethal distending toxins (CDTs), are encoded by several Gram-negative pathogens and have been proposed to enhance virulence by allowing evasion of the immune system. CDTs are trafficked in a retrograde manner from the cell surface through the Golgi apparatus and into the endoplasmic reticulum (ER) before ultimately reaching the host cell nucleus. However, the mechanism by which CDTs exit the ER is not known. Here we show that three central components of the host ER associated degradation (ERAD) machinery, Derlin-2 (Derl2), the E3 ubiquitin-protein ligase Hrd1, and the AAA ATPase p97, are required for intoxication by some CDTs. Complementation of Derl2-deficient cells with Derl2:Derl1 chimeras identified two previously uncharacterized functional domains in Derl2, the N-terminal 88 amino acids and the second ER-luminal loop, as required for intoxication by the CDT encoded by Haemophilus ducreyi (Hd-CDT). In contrast, two motifs required for Derlin-dependent retrotranslocation of ERAD substrates, a conserved WR motif and an SHP box that mediates interaction with the AAA ATPase p97, were found to be dispensable for Hd-CDT intoxication. Interestingly, this previously undescribed mechanism is shared with the plant toxin ricin. These data reveal a requirement for multiple components of the ERAD pathway for CDT intoxication and provide insight into a Derl2-dependent pathway exploited by retrograde trafficking toxins. PMID:25078082

Eshraghi, Aria; Dixon, Shandee D; Tamilselvam, Batcha; Kim, Emily Jin-Kyung; Gargi, Amandeep; Kulik, Julia C; Damoiseaux, Robert; Blanke, Steven R; Bradley, Kenneth A

2014-07-01

53

Cytolethal Distending Toxins Require Components of the ER-Associated Degradation Pathway for Host Cell Entry  

PubMed Central

Intracellular acting protein exotoxins produced by bacteria and plants are important molecular determinants that drive numerous human diseases. A subset of these toxins, the cytolethal distending toxins (CDTs), are encoded by several Gram-negative pathogens and have been proposed to enhance virulence by allowing evasion of the immune system. CDTs are trafficked in a retrograde manner from the cell surface through the Golgi apparatus and into the endoplasmic reticulum (ER) before ultimately reaching the host cell nucleus. However, the mechanism by which CDTs exit the ER is not known. Here we show that three central components of the host ER associated degradation (ERAD) machinery, Derlin-2 (Derl2), the E3 ubiquitin-protein ligase Hrd1, and the AAA ATPase p97, are required for intoxication by some CDTs. Complementation of Derl2-deficient cells with Derl2:Derl1 chimeras identified two previously uncharacterized functional domains in Derl2, the N-terminal 88 amino acids and the second ER-luminal loop, as required for intoxication by the CDT encoded by Haemophilus ducreyi (Hd-CDT). In contrast, two motifs required for Derlin-dependent retrotranslocation of ERAD substrates, a conserved WR motif and an SHP box that mediates interaction with the AAA ATPase p97, were found to be dispensable for Hd-CDT intoxication. Interestingly, this previously undescribed mechanism is shared with the plant toxin ricin. These data reveal a requirement for multiple components of the ERAD pathway for CDT intoxication and provide insight into a Derl2-dependent pathway exploited by retrograde trafficking toxins. PMID:25078082

Eshraghi, Aria; Dixon, Shandee D.; Tamilselvam, Batcha; Kim, Emily Jin-Kyung; Gargi, Amandeep; Kulik, Julia C.; Damoiseaux, Robert; Blanke, Steven R.; Bradley, Kenneth A.

2014-01-01

54

The Origin of Allosteric Functional Modulation: Multiple Pre-existing Pathways  

PubMed Central

While allostery draws increasing attention, not much is known about allosteric mechanisms. Here we argue that in all proteins, allosteric signals transmit through multiple, pre-existing pathways; which pathways dominate depend on protein topologies, specific binding events, covalent modifications and cellular (environmental) conditions. Further, perturbation events at any site on the protein surface (or in the interior) will not create new pathways but only shift the pre-existing ensemble of pathways. Drugs binding at different sites or mutational events in disease shift the ensemble toward the same conformations; however, the relative populations of the different states will change. Consequently the observed functional, conformational, and dynamic effects will be different. This is the origin of allosteric functional modulation in dynamic proteins: allostery does not necessarily need to invoke conformational rearrangements to control protein activity and pre-existing pathways are always defaulted to during allostery regardless of the stimulant and perturbation site in the protein. PMID:19679084

del Sol, Antonio; Tsai, Chung-Jung; Ma, Buyong; Nussinov, Ruth

2009-01-01

55

Thermal Decomposition of Benzyl Radical via Multiple Active Pathways  

NASA Astrophysics Data System (ADS)

The thermal decomposition of benzyl radical (C6H5CH2) has been investigated using a combination infrared absorption spectroscopy in a neon matrix and 118.2 (10.487 eV) photoionization mass spectrometry. Both techniques are coupled with a heated tubular reactor to allow temperature control over the decomposition to indicate relative barrier heights of fragmentation pathways. Three possible chemical mechanisms have been considered. 1) Ring expansion to cycloheptatrienyl radical (C7H7) with subsequent breakdown to HCCH and C5H5, 2) isomerization to the substituted five-membered ring fulvenallene (C5H4=C=CH2), which is of interest to kinetic theorists and finally 3) hydrogen shift to form methyl-substituted phenyl radical, which can then form ortho-benzyne, diacetylene and other fragments. Benzyl radical is generated from two precursors, C6H5CH2CH3 and C6H5CH2Br, and both lead to the appearance of HCCH and C5H5. At slightly hotter temperatures peaks are observed at m/z 90, presumed to be C5H4=C=CH2, and 89, potentially the substituted propargyl C5H4=C=CH. Additionally, decomposition of isotopically substituted parent molecules C6H5CD2CD3 and C6D5CH2CH3 indicates C7H7 as an intermediate due to H/D ratios in fragment molecules.

Buckingham, Grant; Robichaud, David; Ormond, Thomas; Nimlos, Mark R.; Daily, John W.; Ellison, Barney

2014-06-01

56

Distinct signaling mechanisms in multiple developmental pathways by the SCRAMBLED receptor of Arabidopsis.  

PubMed

SCRAMBLED (SCM), a leucine-rich repeat receptor-like kinase in Arabidopsis (Arabidopsis thaliana), is required for positional signaling in the root epidermis and for tissue/organ development in the shoot. To further understand SCM action, we generated a series of kinase domain variants and analyzed their ability to complement scm mutant defects. We found that the SCM kinase domain, but not kinase activity, is required for its role in root epidermal patterning, supporting the view that SCM is an atypical receptor kinase. We also describe a previously uncharacterized role for SCM in fruit dehiscence, because mature siliques from scm mutants fail to open properly. Interestingly, the kinase domain of SCM appears to be dispensable for this developmental process. Furthermore, we found that most of the SCM kinase domain mutations dramatically inhibit inflorescence development. Because this process is not affected in scm null mutants, it is likely that SCM acts redundantly to regulate inflorescence size. The importance of distinct kinase residues for these three developmental processes provides an explanation for the maintenance of the conserved kinase domain in the SCM protein, and it may generally explain its conservation in other atypical kinases. Furthermore, these results indicate that individual leucine-rich repeat receptor-like kinases may participate in multiple pathways using distinct signaling mechanisms to mediate diverse cellular communication events. PMID:25136062

Kwak, Su-Hwan; Woo, Sooah; Lee, Myeong Min; Schiefelbein, John

2014-10-01

57

Oralmotor slowing in multiple sclerosis: Relationship to neuropsychological tasks requiring an oral response  

E-print Network

Oralmotor slowing in multiple sclerosis: Relationship to neuropsychological tasks requiring an oral with multiple sclerosis (MS) patients now exclude tests that require significant motor writing or manual­462.) Keywords: Multiple sclerosis, Neuropsychological functioning, Cognitive functioning, Oral motor speed

Dennis, Nancy

58

Making Progress through California Multiple Pathways: Findings from the ConnectEd Network of Schools Evaluation 2007-2008--Lessons Learned from Our Grantmaking Programs. Insight  

ERIC Educational Resources Information Center

High school students participating in 16 California multiple pathways programs generally graduated at higher rates, met university requirements in greater numbers, performed better on high school exit exams and were more engaged in school and learning. This report summarizes a 2007-2008 study of the ConnectEd Network of Schools, capturing positive…

James Irvine Foundation, 2009

2009-01-01

59

Multiple Use of Magma Pathways: Mechanism for Hybridization  

NASA Astrophysics Data System (ADS)

In the Karakoram Shear Zone, Ladakh, NW India, Miocene leucogranitic dykes form an extensive, varied and complex network, linking the Pangong Range anatectic terrane with leucogranites of the Karakoram Batholith. Water-fluxed Miocene anatexis occurs at upper amphibolite conditions, and was contemporaneous with shearing. The network is characterized by continuous and interconnected leucosomes and dykes, with only rare cross-cutting relationships, forming dyke swarms and more chaotic injection complexes where magmatic rocks cover up to 50% of the outcrop area. Despite this volume of magma, the system was always controlled by solid framework suggesting that it did not flow en masse and that the magma network was not all liquid simultaneously. Leucogranites in this network, carry an isotopic signature intermediate between the two main anatectic rocks in the source, suggesting efficient homogenization of the magmatic products. This meso- to macroscale complex network is also reflected at microscale. Microstructural observations indicate that these magmatic rocks consist dominantly of Qtz, Plg and Kfs in two very distinct appearances, as large irregularly-shaped grains with cuspate boundaries, or/and as fine-grained minerals with lobate boundaries. These two show intimate spatial relationship with fine-grained material forming semi- to continuous corridors to wide channels that links together and form an extensive network branching around large grains. We suggest, that the large minerals represent early formed solid granitic framework that was later invaded by a new melt batch that exploits microfractures in between and through the framework forming crystals giving rise to this interconnected network. The presence of later crystallized melt and its interaction with the solid rock was inferred from the following microstructures: (i) narrow, tortuous corridors of fine-grained minerals cutting across or lining the boundaries of larger grains, interpreted to be remnants of magma-filled cracks cutting across a pre-existing magmatic rock; (ii) compositional zoning of early-crystallized plagioclase and K-feldspar; (iii) quartz overgrows documented by CL imaging; (iv) corrosion of early-formed grains; and (v) different CPO of early-formed quartz and its overgrowths. In summary, the early formed dykes provided a pathway exploited by new magma batches. Once formed, the magma channels remained open either intermittently or continuously and the new melt batches migrated through following predominantly grain boundaries along an S-C fabric related to syn-magmatic shearing. Accordingly, hybrid signature results from the microscopic interaction between previously crystallized magmatic rock and new magma batch, through local equilibration, not from magma mixing. We conclude that leucosomes and magmatic bodies formed by the magma that flushed through them have a complex origin and composition that is reflected in the geochemistry and isotope chemistry. Final composition is a result of the accumulation of magma residue. This in turn depends on compositional changes of magma influx, P-T conditions, and the interaction of new magma with early crystallized magmatic products.

Hasalova, P.; Weinberg, R. F.; Reichardt, H.

2010-12-01

60

Multiple Goals, Multiple Pathways: The Role of Goal Orientation in Learning and Achievement  

Microsoft Academic Search

Mastery goals have been linked to adaptive outcomes in normative goal theory and research; performance goals, to less adaptive outcomes. In contrast, approach performance goals may be adaptive for some outcomes under a revised goal theory perspective. The current study addresses the role of multiple goals, both mastery and approach performance goals, and links them to multiple outcomes of motivation,

Paul R. Pintrich

2000-01-01

61

SUMOylation of ATRIP potentiates DNA damage signaling by boosting multiple protein interactions in the ATR pathway  

PubMed Central

The ATR (ATM [ataxia telangiectasia-mutated]- and Rad3-related) checkpoint is a crucial DNA damage signaling pathway. While the ATR pathway is known to transmit DNA damage signals through the ATR–Chk1 kinase cascade, whether post-translational modifications other than phosphorylation are important for this pathway remains largely unknown. Here, we show that protein SUMOylation plays a key role in the ATR pathway. ATRIP, the regulatory partner of ATR, is modified by SUMO2/3 at K234 and K289. An ATRIP mutant lacking the SUMOylation sites fails to localize to DNA damage and support ATR activation efficiently. Surprisingly, the ATRIP SUMOylation mutant is compromised in the interaction with a protein group, rather than a single protein, in the ATR pathway. Multiple ATRIP-interacting proteins, including ATR, RPA70, TopBP1, and the MRE11–RAD50–NBS1 complex, exhibit reduced binding to the ATRIP SUMOylation mutant in cells and display affinity for SUMO2 chains in vitro, suggesting that they bind not only ATRIP but also SUMO. Fusion of a SUMO2 chain to the ATRIP SUMOylation mutant enhances its interaction with the protein group and partially suppresses its localization and functional defects, revealing that ATRIP SUMOylation promotes ATR activation by providing a unique type of protein glue that boosts multiple protein interactions along the ATR pathway. PMID:24990965

Wu, Ching-Shyi; Ouyang, Jian; Mori, Eiichiro; Nguyen, Hai Dang; Maréchal, Alexandre; Hallet, Alexander; Chen, David J.; Zou, Lee

2014-01-01

62

Use of multiple dispersal pathways facilitates amphibian persistence in stream networks  

E-print Network

Use of multiple dispersal pathways facilitates amphibian persistence in stream networks Evan H. Campbell Granta,b,1 , James D. Nicholsa , Winsor H. Lowec , and William F. Fagand a Northeast Amphibian) Although populations of amphibians are declining worldwide, there is no evidence that salamanders occupying

Lowe, Winsor H.

63

Language Learning in Children Who Are Deaf and Hard of Hearing: Multiple Pathways.  

ERIC Educational Resources Information Center

This text on teaching language to students with hearing impairments stresses the use of multiple language learning pathways to meet the individual needs of students. The introductory chapter looks at language issues in the context of history, instruction, technology, culture, and the law. Chapter 2, on language acquisition, discusses the nature of…

Easterbrooks, Susan R.; Baker, Sharon

64

Environmental pathways to autoimmune diseases: the cases of primary biliary cirrhosis and multiple sclerosis  

PubMed Central

The pathways leading to autoimmunity remain enigmatic despite numerous lines of experimental inquiry and epidemiological evidence. The mechanisms leading to the initiation and perpetuation of specific diseases such as primary biliary cirrhosis (PBC) or multiple sclerosis (MS) remain largely enigmatic, although it is established that a combination of genetic predisposition and environmental stimulation is required. The growing number of genome-wide association studies and the largely incomplete concordance for autoimmune diseases in monozygotic twins concur to support the role of the environment (including infectious agents and chemicals) in the breakdown of tolerance leading to autoimmunity through different mechanisms. In the present article we illustrate the current hypotheses related to an environmental impact on the onset of PBC and MS as two representative conditions investigated with complementary approaches. Indeed, while a role of post-translational antigen modifications has been proposed for MS, this field remain unexplored in PBC where, conversely, most evidence is gathered from geoepidemiology and experimental data on xenobiotics or infectious agents. PMID:22295019

Selmi, Carlo; Maria Papini, Anna; Pugliese, Piera; Claudia Alcaro, Maria; Gershwin, M. Eric

2011-01-01

65

Regulation of multiple DNA repair pathways by the Fanconi anemia protein SLX4.  

PubMed

SLX4, the newly identified Fanconi anemia protein, FANCP, is implicated in repairing DNA damage induced by DNA interstrand cross-linking (ICL) agents, topoisomerase I (TOP1) inhibitors, and in Holliday junction resolution. It interacts with and enhances the activity of XPF-ERCC1, MUS81-EME1, and SLX1 nucleases, but the requirement for the specific nucleases in SLX4 function is unclear. Here, by complementing a null FA-P Fanconi anemia cell line with SLX4 mutants that specifically lack the interaction with each of the nucleases, we show that the SLX4-dependent XPF-ERCC1 activity is essential for ICL repair but is dispensable for repairing TOP1 inhibitor-induced DNA lesions. Conversely, MUS81-SLX4 interaction is critical for resistance to TOP1 inhibitors but is less important for ICL repair. Mutation of SLX4 that abrogates interaction with SLX1 results in partial resistance to both cross-linking agents and TOP1 inhibitors. These results demonstrate that SLX4 modulates multiple DNA repair pathways by regulating appropriate nucleases. PMID:23093618

Kim, Yonghwan; Spitz, Gabriella S; Veturi, Uma; Lach, Francis P; Auerbach, Arleen D; Smogorzewska, Agata

2013-01-01

66

Thermal comfort requirements: A study of people with multiple sclerosis  

SciTech Connect

Existing specifications for thermal comfort in built environments are coming under increased criticism for failing to consider the requirements of specific populations. People with physical disabilities are an example of one such population. This paper presents the results of a study on the thermal comfort requirements of 32 people with multiple sclerosis. Subjects were exposed to three conditions: 18.5 C, PMV = {minus}1.5, slightly cool to cool; 23 C, PMV = 0, neutral; 29 C, PMV = +1.5, slightly warm to warm. Results indicate that people with multiple sclerosis have a wide range of responses to the three experimental conditions. The actual percentage dissatisfied was much higher than predicted by Fange's (1970) predicted percentage dissatisfied. Their preferred environment is slightly warmer than 23 C, PMV = 0, neutral. A subgroup of the population prefers an environment that is slightly cooler than 23 C. Further work is needed to qualify if their preferred environments match that of PMV+1 and PMV{minus}1 and to identify if any of the factors such as age, duration of disability, and medication affect the actual mean vote.

Webb, L.H.; Parsons, K.C.; Hodder, S.G.

1999-07-01

67

Mycobacterial Esx-3 Requires Multiple Components for Iron Acquisition  

PubMed Central

ABSTRACT The type VII secretion systems are conserved across mycobacterial species and in many Gram-positive bacteria. While the well-characterized Esx-1 pathway is required for the virulence of pathogenic mycobacteria and conjugation in the model organism Mycobacterium smegmatis, Esx-3 contributes to mycobactin-mediated iron acquisition in these bacteria. Here we show that several Esx-3 components are individually required for function under low-iron conditions but that at least one, the membrane-bound protease MycP3 of M. smegmatis, is partially expendable. All of the esx-3 mutants tested, including the ?mycP3ms mutant, failed to export the native Esx-3 substrates EsxHms and EsxGms to quantifiable levels, as determined by targeted mass spectrometry. Although we were able to restore low-iron growth to the esx-3 mutants by genetic complementation, we found a wide range of complementation levels for protein export. Indeed, minute quantities of extracellular EsxHms and EsxGms were sufficient for iron acquisition under our experimental conditions. The apparent separation of Esx-3 function in iron acquisition from robust EsxGms and EsxHms secretion in the ?mycP3ms mutant and in some of the complemented esx-3 mutants compels reexamination of the structure-function relationships for type VII secretion systems. PMID:24803520

Siegrist, M. Sloan; Steigedal, Magnus; Ahmad, Rushdy; Mehra, Alka; Dragset, Marte S.; Schuster, Brian M.; Philips, Jennifer A.; Carr, Steven A.

2014-01-01

68

The Toll-Dorsal Pathway Is Required for Resistance to Viral Oral Infection in Drosophila  

PubMed Central

Pathogen entry route can have a strong impact on the result of microbial infections in different hosts, including insects. Drosophila melanogaster has been a successful model system to study the immune response to systemic viral infection. Here we investigate the role of the Toll pathway in resistance to oral viral infection in D. melanogaster. We show that several Toll pathway components, including Spätzle, Toll, Pelle and the NF-kB-like transcription factor Dorsal, are required to resist oral infection with Drosophila C virus. Furthermore, in the fat body Dorsal is translocated from the cytoplasm to the nucleus and a Toll pathway target gene reporter is upregulated in response to Drosophila C Virus infection. This pathway also mediates resistance to several other RNA viruses (Cricket paralysis virus, Flock House virus, and Nora virus). Compared with control, viral titres are highly increased in Toll pathway mutants. The role of the Toll pathway in resistance to viruses in D. melanogaster is restricted to oral infection since we do not observe a phenotype associated with systemic infection. We also show that Wolbachia and other Drosophila-associated microbiota do not interact with the Toll pathway-mediated resistance to oral infection. We therefore identify the Toll pathway as a new general inducible pathway that mediates strong resistance to viruses with a route-specific role. These results contribute to a better understanding of viral oral infection resistance in insects, which is particularly relevant in the context of transmission of arboviruses by insect vectors. PMID:25473839

Ferreira, Álvaro Gil; Naylor, Huw; Esteves, Sara Santana; Pais, Inês Silva; Martins, Nelson Eduardo; Teixeira, Luis

2014-01-01

69

The Toll-dorsal pathway is required for resistance to viral oral infection in Drosophila.  

PubMed

Pathogen entry route can have a strong impact on the result of microbial infections in different hosts, including insects. Drosophila melanogaster has been a successful model system to study the immune response to systemic viral infection. Here we investigate the role of the Toll pathway in resistance to oral viral infection in D. melanogaster. We show that several Toll pathway components, including Spätzle, Toll, Pelle and the NF-kB-like transcription factor Dorsal, are required to resist oral infection with Drosophila C virus. Furthermore, in the fat body Dorsal is translocated from the cytoplasm to the nucleus and a Toll pathway target gene reporter is upregulated in response to Drosophila C Virus infection. This pathway also mediates resistance to several other RNA viruses (Cricket paralysis virus, Flock House virus, and Nora virus). Compared with control, viral titres are highly increased in Toll pathway mutants. The role of the Toll pathway in resistance to viruses in D. melanogaster is restricted to oral infection since we do not observe a phenotype associated with systemic infection. We also show that Wolbachia and other Drosophila-associated microbiota do not interact with the Toll pathway-mediated resistance to oral infection. We therefore identify the Toll pathway as a new general inducible pathway that mediates strong resistance to viruses with a route-specific role. These results contribute to a better understanding of viral oral infection resistance in insects, which is particularly relevant in the context of transmission of arboviruses by insect vectors. PMID:25473839

Ferreira, Álvaro Gil; Naylor, Huw; Esteves, Sara Santana; Pais, Inês Silva; Martins, Nelson Eduardo; Teixeira, Luis

2014-12-01

70

Synergy between Multiple Microtubule-Generating Pathways Confers Robustness to Centrosome-Driven Mitotic Spindle Formation  

PubMed Central

Summary The mitotic spindle is defined by its organized, bipolar mass of microtubules, which drive chromosome alignment and segregation. Although different cells have been shown to use different molecular pathways to generate the microtubules required for spindle formation, how these pathways are coordinated within a single cell is poorly understood. We have tested the limits within which the Drosophila embryonic spindle forms, disrupting the inherent temporal control that overlays mitotic microtubule generation, interfering with the molecular mechanism that generates new microtubules from preexisting ones, and disrupting the spatial relationship between microtubule nucleation and the usually dominant centrosome. Our work uncovers the possible routes to spindle formation in embryos and establishes the central role of Augmin in all microtubule-generating pathways. It also demonstrates that the contributions of each pathway to spindle formation are integrated, highlighting the remarkable flexibility with which cells can respond to perturbations that limit their capacity to generate microtubules. PMID:24389063

Hayward, Daniel; Metz, Jeremy; Pellacani, Claudia; Wakefield, James G.

2014-01-01

71

Multiple myeloma acquires resistance to EGFR inhibitor via induction of pentose phosphate pathway.  

PubMed

Multiple myeloma (MM) was characterized by frequent mutations in KRAS/NRAS/BRAF within the EGFR pathway that could induce resistance to EGFR inhibitors. We here report that EGFR inhibition solely exhibited moderate inhibition in KRAS/NRAS/BRAF wildtype (triple-WT) MM cells, whilst had no effect in myeloma cells with any of the mutated genes. The moderate inhibitory effect was conferred by induction of pentose phosphate pathway (PPP) when cells were treated with Gefitinib, the EGFR inhibitor. Combination of Gefitinib with PPP inhibitor 6AN effected synergistically in triple-WT cells. The inhibition could be restored by addition of NADPH. Dual EGFR/ERBB2 inhibitor Afatinib also exhibited similar effects. Further genetic silencing of EGFR, ERBB2 and mTOR indicated that major effect conferred by ERBB2 was via convergence to EGFR pathway in MM. Our results contributed to the individualized targeted therapy with EGFR inhibitors in MM. PMID:25894462

Chen, Yan; Huang, Ruibin; Ding, Jianghua; Ji, Dexiang; Song, Bing; Yuan, Liya; Chang, Hong; Chen, Guoan

2015-01-01

72

Differential Activities of Thalidomide and Isoprenoid Biosynthetic Pathway Inhibitors in Multiple Myeloma Cells  

PubMed Central

Thalidomide has emerged as an effective agent for treating multiple myeloma, however the precise mechanism of action remains unknown. Agents known to target the isoprenoid biosynthetic pathway (IBP) can have cytotoxic effects in myeloma cells. The interactions between thalidomide and IBP inhibitors in human multiple myeloma cells were evaluated. Enhanced cytotoxicity and induction of apoptosis was observed in RPMI-8226 cells. Examination of intracellular levels of farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP) revealed a wide variance in basal levels and response to IBP inhibitors. These findings provide a mechanism for the differential sensitivity of myeloma cells to pharmacologic manipulation of the IBP. PMID:19646757

Holstein, Sarah A.; Tong, Huaxiang; Hohl, Raymond J.

2013-01-01

73

Promiscuous Mutations Activate the Non-Canonical NF-kB Pathway in Multiple Myeloma  

PubMed Central

Summary Activation of NF-kB has been noted in many tumor types, however only rarely has this been linked to an underlying genetic mutation. An integrated analysis of high-density oligonucleotide array CGH and gene expression profiling data from 155 multiple myeloma samples identified a promiscuous array of abnormalities contributing to the dysregulation of NF-kB in approximately 20% of patients. We report mutations in ten genes causing the inactivation of TRAF2, TRAF3, CYLD, cIAP1/cIAP2, and activation of NFKB1, NFKB2, CD40, LTBR, TACI, and NIK that result primarily in constitutive activation of the non-canonical NF-kB pathway, with the single most common abnormality being inactivation of TRAF3. These results highlight the critical importance of the NF-kB pathway in the pathogenesis of multiple myeloma. PMID:17692805

Keats, Jonathan J.; Fonseca, Rafael; Chesi, Marta; Schop, Roelandt; Baker, Angela; Chng, Wee-Joo; Van Wier, Scott; Tiedemann, Rodger; Shi, Chang-Xin; Sebag, Michael; Braggio, Esteban; Henry, Travis; Zhu, Yuan-Xiao; Fogle, Homer; Price-Troska, Tammy; Ahmann, Gregory; Mancini, Catherine; Brents, Leslie A.; Kumar, Shaji; Greipp, Philip; Dispenzieri, Angela; Bryant, Barb; Mulligan, George; Bruhn, Laurakay; Barrett, Michael; Valdez, Riccardo; Trent, Jeff; Stewart, A. Keith; Carpten, John; Bergsagel, P. Leif

2007-01-01

74

Therapeutic Efficacy of Suppressing the JAK/STAT Pathway in Multiple Models of EAE1  

PubMed Central

Pathogenic T helper cells and myeloid cells are involved in the pathogenesis of Multiple Sclerosis (MS) and Experimental Autoimmune Encephalomyelitis (EAE), an animal model of MS. The JAK/STAT pathway is utilized by numerous cytokines for signaling, and is critical for development, regulation and termination of immune responses. Dysregulation of the JAK/STAT pathway has pathological implications in autoimmune and neuroinflammatory diseases. Many of the cytokines involved in MS/EAE, including IL-6, IL-12, IL-23, IFN-? and GM-CSF, use the JAK/STAT pathway to induce biological responses. Thus, targeting JAKs has implications for treating autoimmune inflammation of the brain. We have utilized AZD1480, a JAK1/2 inhibitor, to investigate the therapeutic potential of inhibiting the JAK/STAT pathway in models of EAE. AZD1480 treatment inhibits disease severity in MOG-induced classical and atypical EAE models by preventing entry of immune cells into the brain, suppressing differentiation of Th1 and Th17 cells, deactivating myeloid cells, inhibiting STAT activation in the brain, and reducing expression of pro-inflammatory cytokines and chemokines. Treatment of SJL/J mice with AZD1480 delays disease onset of PLP-induced relapsing-remitting disease, reduces relapses and diminishes clinical severity. AZD1480 treatment was also effective in reducing ongoing paralysis induced by adoptive transfer of either pathogenic Th1 or Th17 cells. In vivo AZD1480 treatment impairs both the priming and expansion of T-cells, and attenuates antigen-presentation functions of myeloid cells. Inhibition of the JAK/STAT pathway has clinical efficacy in multiple pre-clinical models of MS, suggesting the feasibility of the JAK/STAT pathway as a target for neuroinflammatory diseases. PMID:24323580

Liu, Yudong; Holdbrooks, Andrew T.; De Sarno, Patrizia; Rowse, Amber L.; Yanagisawa, Lora L.; McFarland, Braden C.; Harrington, Laurie E.; Raman, Chander; Sabbaj, Steffanie; Benveniste, Etty N.; Qin, Hongwei

2014-01-01

75

DETECTION OF MULTIPLE PATHWAYS IN THE SPINAL CORD WHITE MATTER USING Q-BALL IMAGING  

E-print Network

DETECTION OF MULTIPLE PATHWAYS IN THE SPINAL CORD WHITE MATTER USING Q-BALL IMAGING J. Cohen-Adad1 this technique to an ex vivo spinal cord of one cat using a 3T scanner, 100 directions and b-values varying from-ventral fibres in the spinal cord. It is a first step towards in vivo characterization of the healthy and injured

76

Multiple Requirements of PLK1 during Mouse Oocyte Maturation  

PubMed Central

Polo-like kinase 1 (PLK1) orchestrates multiple events of cell division. Although PLK1 function has been intensively studied in centriole-containing and rapidly cycling somatic cells, much less is known about its function in the meiotic divisions of mammalian oocytes, which arrest for a long period of time in prophase before meiotic resumption and lack centrioles for spindle assembly. Here, using specific small molecule inhibition combined with live mouse oocyte imaging, we comprehensively characterize meiotic PLK1’s functions. We show that PLK1 becomes activated at meiotic resumption on microtubule organizing centers (MTOCs) and later at kinetochores. PLK1 is required for efficient meiotic resumption by promoting nuclear envelope breakdown. PLK1 is also needed to recruit centrosomal proteins to acentriolar MTOCs to promote normal spindle formation, as well as for stable kinetochore-microtubule attachment. Consequently, PLK1 inhibition leads to metaphase I arrest with misaligned chromosomes activating the spindle assembly checkpoint (SAC). Unlike in mitosis, the metaphase I arrest is not bypassed by the inactivation of the SAC. We show that PLK1 is required for the full activation of the anaphase promoting complex/cyclosome (APC/C) by promoting the degradation of the APC/C inhibitor EMI1 and is therefore essential for entry into anaphase I. Moreover, our data suggest that PLK1 is required for proper chromosome segregation and the maintenance of chromosome condensation during the meiosis I-II transition, independently of the APC/C. Thus, our results define the meiotic roles of PLK1 in oocytes and reveal interesting differential requirements of PLK1 between mitosis and oocyte meiosis in mammals. PMID:25658810

Solc, Petr; Kitajima, Tomoya S.; Yoshida, Shuhei; Brzakova, Adela; Kaido, Masako; Baran, Vladimir; Mayer, Alexandra; Samalova, Pavlina; Motlik, Jan; Ellenberg, Jan

2015-01-01

77

Multiple signaling pathways leading to the activation of interferon regulatory factor 3.  

PubMed

Virus infection of susceptible cells activates multiple signaling pathways that orchestrate the activation of genes, such as cytokines, involved in the antiviral and innate immune response. Among the kinases induced are the mitogen-activated protein (MAP) kinases, Jun-amino terminal kinases (JNK) and p38, the IkappaB kinase (IKK) and DNA-PK. In addition, virus infection also activates an uncharacterized VAK responsible for the C-terminal phosphorylation and subsequent activation of interferon regulatory factor 3 (IRF-3). Virus-mediated activation of IRF-3 through VAK is dependent on viral entry and transcription, since replication deficient virus failed to induce IRF-3 activity. The pathways leading to VAK activation are not well characterized, but IRF-3 appears to represent a novel cellular detection pathway that recognizes viral nucleocapsid (N) structure. Recently, the range of inducers responsible for IRF-3 activation has increased. In addition to virus infection, recognition of bacterial infection mediated through lipopolysaccharide by Toll-like receptor 4 has also been reported. Furthermore, MAP kinase kinase kinase (MAP KKK)-related pathways and DNA-PK induce N-terminal phosphorylation of IRF-3. This review summarizes recent observations in the identification of novel signaling pathways leading to IRF-3 activation. PMID:12213596

Servant, Marc J; Grandvaux, Nathalie; Hiscott, John

2002-09-01

78

Nuclear interactor of ARF and Mdm2 regulates multiple pathways to activate p53.  

PubMed

The p53 tumor suppressor is controlled by an interactive network of factors that stimulate or inhibit its transcriptional activity. Within that network, Mdm2 functions as the major antagonist of p53 by promoting its ubiquitylation and degradation. Conversely, Tip60 activates p53 through direct association on target promoters as well as acetylation of p53 at lysine 120 (K120). This study examines the functional relationship between Mdm2 and Tip60 with a novel p53 regulator, NIAM (nuclear interactor of ARF and Mdm2). Previous work showed NIAM can suppress proliferation and activate p53 independently of ARF, indicating that other factors mediate those activities. Here, we demonstrate that NIAM is a chromatin-associated protein that binds Tip60. NIAM can promote p53 K120 acetylation, although that modification is not required for NIAM to inhibit proliferation or induce p53 transactivation of the p21 promoter. Notably, Tip60 silencing showed it contributes to but is not sufficient for NIAM-mediated p53 activation, suggesting other mechanisms are involved. Indeed, growth-inhibitory forms of NIAM also bind to Mdm2, and increased NIAM expression levels disrupt p53-Mdm2 association, inhibit p53 polyubiquitylation, and prevent Mdm2-mediated inhibition of p53 transcriptional activity. Importantly, loss of NIAM significantly impairs p53 activation. Together, these results show that NIAM activates p53 through multiple mechanisms involving Tip60 association and Mdm2 inhibition. Thus, NIAM regulates 2 critical pathways that control p53 function and are altered in human cancers, implying an important role for NIAM in tumorigenesis. PMID:24621507

Reed, Sara M; Hagen, Jussara; Tompkins, Van S; Thies, Katie; Quelle, Frederick W; Quelle, Dawn E

2014-01-01

79

Humidity sensation requires both mechanosensory and thermosensory pathways in Caenorhabditis elegans.  

PubMed

All terrestrial animals must find a proper level of moisture to ensure their health and survival. The cellular-molecular basis for sensing humidity is unknown in most animals, however. We used the model nematode Caenorhabditis elegans to uncover a mechanism for sensing humidity. We found that whereas C. elegans showed no obvious preference for humidity levels under standard culture conditions, worms displayed a strong preference after pairing starvation with different humidity levels, orienting to gradients as shallow as 0.03% relative humidity per millimeter. Cell-specific ablation and rescue experiments demonstrate that orientation to humidity in C. elegans requires the obligatory combination of distinct mechanosensitive and thermosensitive pathways. The mechanosensitive pathway requires a conserved DEG/ENaC/ASIC mechanoreceptor complex in the FLP neuron pair. Because humidity levels influence the hydration of the worm's cuticle, our results suggest that FLP may convey humidity information by reporting the degree that subcuticular dendritic sensory branches of FLP neurons are stretched by hydration. The thermosensitive pathway requires cGMP-gated channels in the AFD neuron pair. Because humidity levels affect evaporative cooling, AFD may convey humidity information by reporting thermal flux. Thus, humidity sensation arises as a metamodality in C. elegans that requires the integration of parallel mechanosensory and thermosensory pathways. This hygrosensation strategy, first proposed by Thunberg more than 100 y ago, may be conserved because the underlying pathways have cellular and molecular equivalents across a wide range of species, including insects and humans. PMID:24843133

Russell, Joshua; Vidal-Gadea, Andrés G; Makay, Alex; Lanam, Carolyn; Pierce-Shimomura, Jonathan T

2014-06-01

80

Humidity sensation requires both mechanosensory and thermosensory pathways in Caenorhabditis elegans  

PubMed Central

All terrestrial animals must find a proper level of moisture to ensure their health and survival. The cellular-molecular basis for sensing humidity is unknown in most animals, however. We used the model nematode Caenorhabditis elegans to uncover a mechanism for sensing humidity. We found that whereas C. elegans showed no obvious preference for humidity levels under standard culture conditions, worms displayed a strong preference after pairing starvation with different humidity levels, orienting to gradients as shallow as 0.03% relative humidity per millimeter. Cell-specific ablation and rescue experiments demonstrate that orientation to humidity in C. elegans requires the obligatory combination of distinct mechanosensitive and thermosensitive pathways. The mechanosensitive pathway requires a conserved DEG/ENaC/ASIC mechanoreceptor complex in the FLP neuron pair. Because humidity levels influence the hydration of the worm’s cuticle, our results suggest that FLP may convey humidity information by reporting the degree that subcuticular dendritic sensory branches of FLP neurons are stretched by hydration. The thermosensitive pathway requires cGMP-gated channels in the AFD neuron pair. Because humidity levels affect evaporative cooling, AFD may convey humidity information by reporting thermal flux. Thus, humidity sensation arises as a metamodality in C. elegans that requires the integration of parallel mechanosensory and thermosensory pathways. This hygrosensation strategy, first proposed by Thunberg more than 100 y ago, may be conserved because the underlying pathways have cellular and molecular equivalents across a wide range of species, including insects and humans. PMID:24843133

Russell, Joshua; Vidal-Gadea, Andrés G.; Makay, Alex; Lanam, Carolyn; Pierce-Shimomura, Jonathan T.

2014-01-01

81

Multiple pathways of cell invasion are regulated by multiple families of serine proteases  

Microsoft Academic Search

The complex process of tumor invasion requires the coordinated expression and activity of cell-substratum adhesive interactions\\u000a and of cell-associated protease systems, which destroy the extracellular matrix (ECM), in order to enable the invading cells\\u000a to simultaneously grip and destroy the anatomical barriers that control cell spreading. A number of data indicate that such\\u000a a `grip and go' process may be

Mario Del Rosso; Gabriella Fibbi; Marco Pucci; Silvia D'Alessio; Angela Del Rosso; Lucia Magnelli; Vincenzo Chiarugi

2002-01-01

82

Durable adoptive immunotherapy for leukemia produced by manipulation of multiple regulatory pathways of CD8+ T cell tolerance  

PubMed Central

Tolerizing mechanisms within the host and tumor microenvironment inhibit T cell effector functions that can control cancer. These mechanisms blunt adoptive immunotherapy with infused T cells due to a complex array of signals that determine T cell tolerance, survival, or deletion. Ligation of the negative regulatory receptors CTLA4, PD-1(PDCD1) or LAG3 on T cells normally hinders their response to antigen through non-redundant biochemical processes that interfere with stimulatory pathways. In this study, we used an established mouse model of T cell tolerance to define the roles of these inhibitory receptors in regulating CD8+ T cell tolerance during adoptive immunotherapy to treat leukemia. Blocking CTLA4 and PD-1 in vivo combined to promote survival of transferred T cells despite powerful deletional signals that mediate Bim (BCL2L11)-dependent apoptosis. However, this dual blockade was not optimal for stimulating effector function by responding T cells, which required the additional blockade of LAG3 to induce full expansion and allow the acquisition of robust cytolytic activity. Thus, the cooperation of multiple distinct regulatory pathways was needed for the survival and effector differentiation of adoptively transferred tumor-reactive CD8+ T cells. Our work defines the immune escape pathways where simultaneous blockade could yield durable immunotherapeutic responses that can eradicate disseminated leukemia. PMID:23188506

Berrien-Elliott, Melissa M.; Jackson, Stephanie R.; Meyer, Jennifer M.; Rouskey, Craig J.; Nguyen, Thanh-Long M.; Yagita, Hideo; Greenberg, Philip D.; DiPaolo, Richard J.; Teague, Ryan M.

2012-01-01

83

Evolutionary study of the isoflavonoid pathway based on multiple copies analysis in soybean  

PubMed Central

Background Previous studies suggest that the metabolic pathway structure influences the selection and evolution rates of involved genes. However, most of these studies have exclusively considered a single gene copy encoding each enzyme in the metabolic pathway. Considering multiple-copy encoding enzymes could provide direct evidence of gene evolution and duplication patterns in metabolic pathways. We conducted a detailed analysis of the phylogeny, synteny, evolutionary rate and selection pressure of the genes in the isoflavonoid metabolic pathway of soybeans. Results The results revealed that 1) only the phenylalanine ammonia-lyase (PAL) gene family most upstream from the pathway preserved all of the ancient and recent segmental duplications and maintained a strongly conserved synteny among these duplicated segments; gene families encoding branch-point enzymes with higher pleiotropy tended to retain more types of duplication; and genes encoding chalcone reductase (CHR) and isoflavone synthase (IFS) specific for legumes retained only recent segmental duplications; 2) downstream genes evolved faster than upstream genes and were subject to positive selection or relaxed selection constraints; 3) gene members encoding enzymes with high pleiotropy at the branching points were more likely to have undergone evolutionary differentiation, which may correspond to their functional divergences. Conclusions We reconciled our results with existing controversies and proposed that gene copies at branch points with higher connectivity might be under stronger selective constraints and that the gene copies controlling metabolic flux allocation underwent positive selection. Our analyses demonstrated that the structure and function of a metabolic pathway shapes gene duplication and the evolutionary constraints of constituent enzymes. PMID:24962214

2014-01-01

84

The sumoylation pathway is dysregulated in multiple myeloma and is associated with adverse patient outcome  

PubMed Central

Multiple myeloma (MM) is a plasma cell neoplasm that proceeds through a premalignant state of monoclonal gammopathy of unknown significance; however, the molecular events responsible for myelomagenesis remain uncharacterized. To identify cellular pathways deregulated in MM, we addressed that sumoylation is homologous to ubiquitination and results in the attachment of the ubiquitin-like protein Sumo onto target proteins. Sumoylation was markedly enhanced in MM patient lysates compared with normal plasma cells and expression profiling indicated a relative induction of sumoylation pathway genes. The Sumo-conjugating enzyme Ube2I, the Sumo-ligase PIAS1, and the Sumo-inducer ARF were elevated in MM patient samples and cell lines. Survival correlated with expression because 80% of patients with low UBE2I and PIAS1 were living 6 years after transplantation, whereas only 45% of patients with high expression survived 6 years. UBE2I encodes the sole Sumo-conjugating enzyme in mammalian cells and cells transfected with a dominant-negative sumoylation-deficient UBE2I mutant exhibited decreased survival after radiation exposure, impaired adhesion to bone marrow stroma cell and decreased bone marrow stroma cell–induced proliferation. UBE2I confers cells with multiple advantages to promote tumorigenesis and predicts decreased survival when combined with PIAS1. The sumoylation pathway is a novel therapeutic target with implications for existing proteasomal-based treatment strategies. PMID:19965618

Pelluru, Dheeraj; Lefkimmiatis, Konstantinos; Fulciniti, Mariateresa; Prabhala, Rao H.; Greipp, Philip R.; Barlogie, Bart; Tai, Yu-Tzu; Anderson, Kenneth C.; Shaughnessy, John D.; Annunziata, Christina M.

2010-01-01

85

Activation of Multiple Apoptotic Pathways in Human Nasopharyngeal Carcinoma Cells by the Prenylated Isoflavone, Osajin  

PubMed Central

Osajin is a prenylated isoflavone showing antitumor activity in different tumor cell lines. The underlying mechanism of osajin-induced cancer cell death is not clearly understood. In the present study, the mechanisms of osajin-induced cell death of human nasopharyngeal carcinoma (NPC) cells were explored. Osajin was found to significantly induce apoptosis of NPC cells in a dose- and time-dependent manner. Multiple molecular effects were observed during osajin treatment including a significant loss of mitochondrial transmembrane potential, release of cytochrome c into the cytosol, enhanced expression of Fas ligand (FasL), suppression of glucose-regulated protein 78 kDa (GRP78), and activation of caspases-9, -8, -4 and -3. In addition, up-regulation of proapoptotic Bax protein and down-regulation of antiapoptotic Bcl-2 protein were also observed. Taken together, osajin induces apoptosis in human NPC cells through multiple apoptotic pathways, including the extrinsic death receptor pathway, and intrinsic pathways relying on mitochondria and endoplasmic reticulum stress. Thus, osajin could be developed as a new effective and chemopreventive compound for human NPC. PMID:21532751

Huang, Tsung-Teng; Liu, Fu-Guo; Wei, Chia-Fong; Lu, Chia-Chen; Chen, Chang-Chieh; Lin, Hung-Chi; Ojcius, David M.; Lai, Hsin-Chih

2011-01-01

86

TNF provokes cardiomyocyte apoptosis and cardiac remodeling through activation of multiple cell death pathways  

PubMed Central

Transgenic mice with cardiac-restricted overexpression of secretable TNF (MHCsTNF) develop progressive LV wall thinning and dilation accompanied by an increase in cardiomyocyte apoptosis and a progressive loss of cytoprotective Bcl-2. To test whether cardiac-restricted overexpression of Bcl-2 would prevent adverse cardiac remodeling, we crossed MHCsTNF mice with transgenic mice harboring cardiac-restricted overexpression of Bcl-2. Sustained TNF signaling resulted in activation of the intrinsic cell death pathway, leading to increased cytosolic levels of cytochrome c, Smac/Diablo and Omi/HtrA2, and activation of caspases -3 and -9. Cardiac-restricted overexpression of Bcl-2 blunted activation of the intrinsic pathway and prevented LV wall thinning; however, Bcl-2 only partially attenuated cardiomyocyte apoptosis. Subsequent studies showed that c-FLIP was degraded, that caspase-8 was activated, and that Bid was cleaved to t-Bid, suggesting that the extrinsic pathway was activated concurrently in MHCsTNF hearts. As expected, cardiac Bcl-2 overexpression had no effect on extrinsic signaling. Thus, our results suggest that sustained inflammation leads to activation of multiple cell death pathways that contribute to progressive cardiomyocyte apoptosis; hence the extent of such programmed myocyte cell death is a critical determinant of adverse cardiac remodeling. PMID:17694177

Haudek, Sandra B.; Taffet, George E.; Schneider, Michael D.; Mann, Douglas L.

2007-01-01

87

Representation of contextually related multiple objects in the human ventral visual pathway.  

PubMed

Real-world scenes usually contain a set of cluttered and yet contextually related objects. Here we used fMRI to investigate where and how contextually related multiple objects were represented in the human ventral visual pathway. Specifically, we measured the responses in face-selective and body-selective regions along the ventral pathway when faces and bodies were presented either simultaneously or in isolation. We found that, in the posterior regions, the response for the face and body pair was the weighted average response for faces and bodies presented in isolation. In contrast, the anterior regions encoded the face and body pair in a mutually facilitative fashion, with the response for the pair significantly higher than that for its constituent objects. Furthermore, in the right fusiform face area, the face and body pair was represented as one inseparable object, possibly to reduce perceptual load and increase representation efficiency. Therefore, our study suggests that the visual system uses a hierarchical representation scheme to process multiple objects in natural scenes: the average mechanism in posterior regions helps retaining information of individual objects in clutter, whereas the nonaverage mechanism in the anterior regions uses the contextual information to optimize the representation for multiple objects. PMID:23772557

Song, Yiying; Luo, Yu L L; Li, Xueting; Xu, Miao; Liu, Jia

2013-08-01

88

Curcumin suppresses proliferation and induces apoptosis in human biliary cancer cells through modulation of multiple cell signaling pathways.  

PubMed

Cholangiocarcinoma (CCA) is a tumor with poor prognosis that is resistant to all currently available treatments. Whether curcumin, a nutraceutical derived from turmeric (Curcuma longa), has potential therapeutic activity against human CCA was investigated using three CCA cell lines (KKU100, KKU-M156 and KKU-M213). Examination of mitochondrial dehydrogenase activity, phosphatidylserine externalization, esterase staining, caspase activation and poly-adenosine diphosphate ribose polymerase cleavage demonstrated that curcumin inhibited proliferation of and induced apoptosis in these biliary cancer cells. Colony-formation assay confirmed the growth-inhibitory effect of curcumin on CCA cells. When examined for the mechanism, curcumin was found to activate multiple cell signaling pathways in these cells. First, all CCA cells exhibited constitutively active nuclear factor (NF)-?B, and treatment with curcumin abolished this activation as indicated by DNA binding, nuclear translocation and p65 phosphorylation. Second, curcumin suppressed activation of signal transducer and activator of transcription-3 as indicated by decreased phosphorylation at both tyrosine(705) and serine(727) and inhibition of janus kinase-1 phosphorylation. Third, curcumin induced expression of peroxisome proliferator-activated receptor gamma. Fourth, curcumin upregulated death receptors, DR4 and DR5. Fifth, curcumin suppressed the Akt activation pathway. Sixth, curcumin inhibited expression of cell survival proteins such as B-cell lymphoma-2, B-cell leukemia protein xL, X-linked inhibitor of apoptosis protein, c-FLIP, cellular inhibitor of apoptosis protein (cIAP)-1, cIAP-2 and survivin and proteins linked to cell proliferation, such as cyclin D1 and c-Myc. Seventh, the growth inhibitory effect of curcumin was enhanced in the I?B kinase-deficient cells, the enzyme required for nuclear factor-kappaB activation. Overall, our results indicate that curcumin mediates its antiproliferative and apoptotic effects through activation of multiple cell signaling pathways, and thus, its activity against CCA should be further investigated. PMID:21325634

Prakobwong, Suksanti; Gupta, Subash C; Kim, Ji Hye; Sung, Bokyung; Pinlaor, Porntip; Hiraku, Yusuke; Wongkham, Sopit; Sripa, Banchob; Pinlaor, Somchai; Aggarwal, Bharat B

2011-09-01

89

Investigating sources and pathways of perfluoroalkyl acids (PFAAs) in aquifers in Tokyo using multiple tracers.  

PubMed

We employed a multi-tracer approach to investigate sources and pathways of perfluoroalkyl acids (PFAAs) in urban groundwater, based on 53 groundwater samples taken from confined aquifers and unconfined aquifers in Tokyo. While the median concentrations of groundwater PFAAs were several ng/L, the maximum concentrations of perfluorooctane sulfonate (PFOS, 990 ng/L), perfluorooctanoate (PFOA, 1800 ng/L) and perfluorononanoate (PFNA, 620 ng/L) in groundwater were several times higher than those of wastewater and street runoff reported in the literature. PFAAs were more frequently detected than sewage tracers (carbamazepine and crotamiton), presumably owing to the higher persistence of PFAAs, the multiple sources of PFAAs beyond sewage (e.g., surface runoff, point sources) and the formation of PFAAs from their precursors. Use of multiple methods of source apportionment including principal component analysis-multiple linear regression (PCA-MLR) and perfluoroalkyl carboxylic acid ratio analysis highlighted sewage and point sources as the primary sources of PFAAs in the most severely polluted groundwater samples, with street runoff being a minor source (44.6% sewage, 45.7% point sources and 9.7% street runoff, by PCA-MLR). Tritium analysis indicated that, while young groundwater (recharged during or after the 1970s, when PFAAs were already in commercial use) in shallow aquifers (<50 m depth) was naturally highly vulnerable to PFAA pollution, PFAAs were also found in old groundwater (recharged before the 1950s, when PFAAs were not in use) in deep aquifers (50-500 m depth). This study demonstrated the utility of multiple uses of tracers (pharmaceuticals and personal care products; PPCPs, tritium) and source apportionment methods in investigating sources and pathways of PFAAs in multiple aquifer systems. PMID:24814036

Kuroda, Keisuke; Murakami, Michio; Oguma, Kumiko; Takada, Hideshige; Takizawa, Satoshi

2014-08-01

90

Snail coordinately regulates downstream pathways to control multiple aspects of mammalian neural precursor development.  

PubMed

The Snail transcription factor plays a key role in regulating diverse developmental processes but is not thought to play a role in mammalian neural precursors. Here, we have examined radial glial precursor cells of the embryonic murine cortex and demonstrate that Snail regulates their survival, self-renewal, and differentiation into intermediate progenitors and neurons via two distinct and separable target pathways. First, Snail promotes cell survival by antagonizing a p53-dependent death pathway because coincident p53 knockdown rescues survival deficits caused by Snail knockdown. Second, we show that the cell cycle phosphatase Cdc25b is regulated by Snail in radial precursors and that Cdc25b coexpression is sufficient to rescue the decreased radial precursor proliferation and differentiation observed upon Snail knockdown. Thus, Snail acts via p53 and Cdc25b to coordinately regulate multiple aspects of mammalian embryonic neural precursor biology. PMID:24719096

Zander, Mark A; Burns, Sarah E; Yang, Guang; Kaplan, David R; Miller, Freda D

2014-04-01

91

Snail Coordinately Regulates Downstream Pathways to Control Multiple Aspects of Mammalian Neural Precursor Development  

PubMed Central

The Snail transcription factor plays a key role in regulating diverse developmental processes but is not thought to play a role in mammalian neural precursors. Here, we have examined radial glial precursor cells of the embryonic murine cortex and demonstrate that Snail regulates their survival, self-renewal, and differentiation into intermediate progenitors and neurons via two distinct and separable target pathways. First, Snail promotes cell survival by antagonizing a p53-dependent death pathway because coincident p53 knockdown rescues survival deficits caused by Snail knockdown. Second, we show that the cell cycle phosphatase Cdc25b is regulated by Snail in radial precursors and that Cdc25b coexpression is sufficient to rescue the decreased radial precursor proliferation and differentiation observed upon Snail knockdown. Thus, Snail acts via p53 and Cdc25b to coordinately regulate multiple aspects of mammalian embryonic neural precursor biology. PMID:24719096

Zander, Mark A.; Burns, Sarah E.; Yang, Guang; Kaplan, David R.

2014-01-01

92

Apoptosis of bone marrow mesenchymal stem cells caused by hypoxia/reoxygenation via multiple pathways  

PubMed Central

The irreversible loss of cardiomyocytes remains a key problem to resolve, which forms the cellular basis of cardiac dysfunction. MSCs transplantation brings out a promising potential for myocardial renovation with less limitations. However, this cell transplantation therapy is limited by its poor viability after transplantation. Apoptosis is thought to be the major factor that affects the efficiency of MSCs transplantation. Therefore, exploring the process of apoptosis and the underlying mechanisms of MSCs in the ‘harmful’ microenvironment is significant for the sake of improving the efficiency of MSCs transplantation therapy. A hypoxia/reoxygenation (H/R) model of MSCs had been established. TUNEL, Hoechst staining and MTT were used for the evaluation of morphological changes, cell viability and apoptosis. Mitochondrial transmembrane potential was detected by JC-1 using the fluorescence microscopy system. The protein expression of cytochrome c, p-ERK, p-AKT, Bcl-2, Bax, p-JNK, HIF-1? and VEGF was assessed for the analysis of protein changes using the Western blot. In our study, H/R insult lead to apoptosis and cell viability lost in a time-dependent manner in MSCs. Multiple pathways were involved in the apoptosis of MSCs, including cytochrome c released from mitochondria to cytosol, mitochondrial transmembrane potential lost. In addition, p-ERK and p-AKT were downregulated, while Bcl-2, p-JNK and VEGF were upregulated. H/R induced the apoptosis in MSCs is through multiple pathways. These multiple pathways will be helpful for understanding and explaining the process and mechanism of apoptosis in MSCs. PMID:25663966

Chen, Tie-Long; Zhu, Guang-Li; Wang, Jian-An; Wang, Yu; He, Xiao-Long; Jiang, Jun

2014-01-01

93

Asthma Is Associated with Multiple Alterations in Anti-Viral Innate Signalling Pathways  

PubMed Central

Background Human rhinovirus (HRV) infection is a major trigger for asthma exacerbations. Anti-viral immunity appears to be abnormal in asthma, with immune dysfunction reported in both airway structural cells and migratory, bone marrow derived cells. Though decreased capacity to produce anti-viral interferons (IFNs) has been reported in asthma, a detailed analysis of the molecular events involved has not been undertaken. Objective To compare the molecular pathway controlling type I IFN synthesis in HRV-stimulated peripheral blood mononuclear cells (PBMC) from asthmatic and healthy subjects. Methods PBMC from 22 allergic asthmatics and 20 healthy donors were cultured with HRV for 24 hours. Multiple components of the Toll-like receptor (TLR), IFN regulatory and NF?? pathways were compared at the mRNA and protein level. Results Multiple deficiencies in the innate immune response to HRV were identified in asthma, with significantly lower expression of IFN?, IFN? and interferon stimulated genes than in healthy subjects. This was accompanied by reduced expression of intra-cellular signalling molecules including interferon regulatory factors (IRF1, IRF7), NF-?B family members (p50, p52, p65 and I?K?) and STAT1, and by reduced responsiveness to TLR7/TLR8 activation. These observations could not be attributed to alterations in the numbers of dendritic cell (DC) subsets in asthma or baseline expression of the viral RNA sensing receptors TLR7/TLR8. In healthy subjects, blocking the activity of type-I IFN or depleting plasmacytoid DC recapitulated many of the abnormalities observed in asthma. Conclusions Multiple abnormalities in innate anti-viral signalling pathways were identified in asthma, with deficiencies in both IFN-dependent and IFN-independent molecules identified. PMID:25203745

Pritchard, Antonia L.; White, Olivia J.; Burel, Julie G.; Carroll, Melanie L.; Phipps, Simon; Upham, John W.

2014-01-01

94

Initiation of Rhombomeric Hoxb4 Expression Requires Induction by Somites and a Retinoid Pathway  

Microsoft Academic Search

Anteroposterior (AP) patterning in the vertebrate hindbrain is dependent upon the establishment of segmental domains of Hox expression. We investigated the mechanism that governs the early expression of Hoxb4 and found that transient signaling from the paraxial mesoderm induces expression in the hindbrain. Induction involves a retinoid pathway requiring retinoic acid receptor (RAR) function within the neural plate. Characterization of

Alex Gould; Nobue Itasaki; Robb Krumlauf

1998-01-01

95

Signaling pathways required for macrophage scavenger receptor-mediated phagocytosis: analysis by scanning cytometry  

Microsoft Academic Search

BACKGROUND: Scavenger receptors are important components of the innate immune system in the lung, allowing alveolar macrophages to bind and phagocytose numerous unopsonized targets. Mice with genetic deletions of scavenger receptors, such as SR-A and MARCO, are susceptible to infection or inflammation from inhaled pathogens or dusts. However, the signaling pathways required for scavenger receptor-mediated phagocytosis of unopsonized particles have

Timothy H Sulahian; Amy Imrich; Glen DeLoid; Aaron R Winkler; Lester Kobzik

2008-01-01

96

Suppressed RNA-polymerase 1 pathway is associated with benign multiple sclerosis.  

PubMed

Benign multiple sclerosis (BMS) occurs in about 15% of patients with relapsing-remitting multiple sclerosis (RRMS) that over time do not develop significant neurological disability. The molecular events associated with BMS are not clearly understood. This study sought to underlie the biological mechanisms associated with BMS. Blood samples obtained from a cohort of 31 patients with BMS and 36 patients with RRMS were applied for gene expression microarray analysis using HG-U133A-2 array (Affymetrix). Data were analyzed by Partek and pathway reconstruction was performed by Ingenuity for the most informative genes (MIGs). We identified a differing gene expression signature of 406 MIGs between BMS patients, mean±SE age 44.5±1.5 years, 24 females, 7 males, EDSS 1.9±0.2, disease duration 17.0±1.3 years, and RRMS patients, age 40.3±1.8 years, 24 females, 12 males, EDSS 3.5±0.2, disease duration 10.9±1.4 years. The signature was enriched by genes related RNA polymerase I (POL-1) transcription, general inflammatory response and activation of cell death. The most significant under-expressed pathway operating in BMS was the POL-1 pathway (p = 4.0*10(-5)) known while suppressed to activate P53 dependent apoptosis and to suppress NF?B induced inflammation. In accordance, of the 30 P53 target genes presented within the BMS signature, 19 had expression direction consistent with P53 activation. The transcripts within the pathway include POL-1 transcription factor 3 (RRN3, p = 4.8*10(-5)), POL-1 polypeptide D (POLR1D, p = 2.2*10(-4)), leucine-rich PPR-motif containing protein (LRPPRC p = 2.3*10(-5)), followed by suppression of the downstream family of ribosomal genes like RPL3, 6,13,22 and RPS6. In accordance POL-1 transcript and release factor PTRF that terminates POL-1 transcription, was over-expressed (p = 4.4*10(-3)). Verification of POL-1 pathway key genes was confirmed by qRT-PCR, and RRN3 silencing resulted in significant increase in the apoptosis level of PBMC sub-populations in RRMS patients. Our findings demonstrate that suppression of POL-1 pathway induce the low disease activity of BMS. PMID:23077530

Achiron, Anat; Feldman, Anna; Magalashvili, David; Dolev, Mark; Gurevich, Michael

2012-01-01

97

Induction of Multiple Immune Regulatory Pathways with Differential Impact in HCV/HIV Coinfection  

PubMed Central

Persistent viral infections including HCV, HBV, and HIV are associated with increased immune regulatory pathways including the extrinsic FoxP3+CD4+ regulatory T cells (Tregs) and intrinsic inhibitory pathways such as programed death-1 (PD-1) and cytotoxic T lymphocyte antigen-4 (CTLA-4) with potentially reversible suppression of antiviral effector T cells (1–12). Immunological consequences of viral coinfections relative to these immune regulatory pathways and their interplay are not well-defined. In this study, we examined the frequency, phenotype, and effector function of circulating T cell subsets in patients with chronic HCV and/or HIV infection, hypothesizing that HCV/HIV coinfection will result in greater immune dysregulation with pathogenetic consequences (13, 14). We show that multiple T cell inhibitory pathways are induced in HCV/HIV coinfection including FoxP3+ Tregs, PD-1, and CTLA-4 in inverse association with overall CD4 T cell frequency but not with liver function or HCV RNA titers. The inverse association between CD4 T cell frequency and their FoxP3, PD-1, or CTLA-4 expression remained significant in all subjects combined regardless of HCV and/or HIV infection, suggesting a global homeostatic mechanism to maintain immune regulation relative to CD4 T cell frequency. PD-1 blockade rescued T cell responses to HIV but not HCV without significant impact by CTLA-4 blockade in vitro. Collectively, these findings highlight complex immune interactions in viral coinfections and differential regulatory pathways influencing virus-specific T cells that are relevant in immunotherapeutic development. PMID:25071758

Cho, Hyosun; Kikuchi, Masahiro; Li, Yun; Nakamoto, Nobuhiro; Amorosa, Valerianna K.; Valiga, Mary E.; Chang, Kyong-Mi

2014-01-01

98

Associations between Proprioceptive Neural Pathway Structural Connectivity and Balance in People with Multiple Sclerosis  

PubMed Central

Mobility and balance impairments are a hallmark of multiple sclerosis (MS), affecting nearly half of patients at presentation and resulting in decreased activity and participation, falls, injuries, and reduced quality of life. A growing body of work suggests that balance impairments in people with mild MS are primarily the result of deficits in proprioception, the ability to determine body position in space in the absence of vision. A better understanding of the pathophysiology of balance disturbances in MS is needed to develop evidence-based rehabilitation approaches. The purpose of the current study was to (1) map the cortical proprioceptive pathway in vivo using diffusion-weighted imaging and (2) assess associations between proprioceptive pathway white matter microstructural integrity and performance on clinical and behavioral balance tasks. We hypothesized that people with MS (PwMS) would have reduced integrity of cerebral proprioceptive pathways, and that reduced white matter microstructure within these tracts would be strongly related to proprioceptive-based balance deficits. We found poorer balance control on proprioceptive-based tasks and reduced white matter microstructural integrity of the cortical proprioceptive tracts in PwMS compared with age-matched healthy controls (HC). Microstructural integrity of this pathway in the right hemisphere was also strongly associated with proprioceptive-based balance control in PwMS and controls. Conversely, while white matter integrity of the right hemisphere’s proprioceptive pathway was significantly correlated with overall balance performance in HC, there was no such relationship in PwMS. These results augment existing literature suggesting that balance control in PwMS may become more dependent upon (1) cerebellar-regulated proprioceptive control, (2) the vestibular system, and/or (3) the visual system. PMID:25368564

Fling, Brett W.; Dutta, Geetanjali Gera; Schlueter, Heather; Cameron, Michelle H.; Horak, Fay B.

2014-01-01

99

APL-1, the Alzheimer’s Amyloid Precursor Protein in Caenorhabditis elegans, Modulates Multiple Metabolic Pathways Throughout Development  

PubMed Central

Mutations in the amyloid precursor protein (APP) gene or in genes that process APP are correlated with familial Alzheimer’s disease (AD). The biological function of APP remains unclear. APP is a transmembrane protein that can be sequentially cleaved by different secretases to yield multiple fragments, which can potentially act as signaling molecules. Caenorhabditis elegans encodes one APP-related protein, APL-1, which is essential for viability. Here, we show that APL-1 signaling is dependent on the activity of the FOXO transcription factor DAF-16 and the nuclear hormone receptor DAF-12 and influences metabolic pathways such as developmental progression, body size, and egg-laying rate. Furthermore, apl-1(yn5) mutants, which produce high levels of the extracellular APL-1 fragment, show an incompletely penetrant temperature-sensitive embryonic lethality. In a genetic screen to isolate mutants in which the apl-1(yn5) lethality rate is modified, we identified a suppressor mutation in MOA-1/R155.2, a receptor-protein tyrosine phosphatase, and an enhancer mutation in MOA-2/B0495.6, a protein involved in receptor-mediated endocytosis. Knockdown of apl-1 in an apl-1(yn5) background caused lethality and molting defects at all larval stages, suggesting that apl-1 is required for each transitional molt. We suggest that signaling of the released APL-1 fragment modulates multiple metabolic states and that APL-1 is required throughout development. PMID:22466039

Ewald, Collin Y.; Raps, Daniel A.; Li, Chris

2012-01-01

100

The Toll pathway is required in the epidermis for muscle development in the Drosophila embryo  

NASA Technical Reports Server (NTRS)

The Toll signaling pathway functions in several Drosophila processes, including dorsal-ventral pattern formation and the immune response. Here, we demonstrate that this pathway is required in the epidermis for proper muscle development. Previously, we showed that the zygotic Toll protein is necessary for normal muscle development; in the absence of zygotic Toll, close to 50% of hemisegments have muscle patterning defects consisting of missing, duplicated and misinserted muscle fibers (Halfon, M.S., Hashimoto, C., and Keshishian, H., Dev. Biol. 169, 151-167, 1995). We have now also analyzed the requirements for easter, spatzle, tube, and pelle, all of which function in the Toll-mediated dorsal-ventral patterning pathway. We find that spatzle, tube, and pelle, but not easter, are necessary for muscle development. Mutations in these genes give a phenotype identical to that seen in Toll mutants, suggesting that elements of the same pathway used for Toll signaling in dorsal-ventral development are used during muscle development. By expressing the Toll cDNA under the control of distinct Toll enhancer elements in Toll mutant flies, we have examined the spatial requirements for Toll expression during muscle development. Expression of Toll in a subset of epidermal cells that includes the epidermal muscle attachment cells, but not Toll expression in the musculature, is necessary for proper muscle development. Our results suggest that signals received by the epidermis early during muscle development are an important part of the muscle patterning process.

Halfon, M. S.; Keshishian, H.

1998-01-01

101

Simultaneous Reconstruction of Multiple Signaling Pathways via the Prize-Collecting Steiner Forest Problem  

PubMed Central

Abstract Signaling and regulatory networks are essential for cells to control processes such as growth, differentiation, and response to stimuli. Although many “omic” data sources are available to probe signaling pathways, these data are typically sparse and noisy. Thus, it has been difficult to use these data to discover the cause of the diseases and to propose new therapeutic strategies. We overcome these problems and use “omic” data to reconstruct simultaneously multiple pathways that are altered in a particular condition by solving the prize-collecting Steiner forest problem. To evaluate this approach, we use the well-characterized yeast pheromone response. We then apply the method to human glioblastoma data, searching for a forest of trees, each of which is rooted in a different cell-surface receptor. This approach discovers both overlapping and independent signaling pathways that are enriched in functionally and clinically relevant proteins, which could provide the basis for new therapeutic strategies. Although the algorithm was not provided with any information about the phosphorylation status of receptors, it identifies a small set of clinically relevant receptors among hundreds present in the interactome. PMID:23383998

Tuncbag, Nurcan; Braunstein, Alfredo; Pagnani, Andrea; Huang, Shao-Shan Carol; Chayes, Jennifer; Borgs, Christian; Zecchina, Riccardo

2013-01-01

102

Gene profiling of keloid fibroblasts shows altered expression in multiple fibrosis-associated pathways  

PubMed Central

Keloids are benign tumors of the dermis that form during a protracted wound healing process. Susceptibility to keloid formation occurs predominantly in people of African and Asian descent. The key alteration(s) responsible for keloid formation has not been identified and there is no satisfactory treatment for this disorder. The altered regulatory mechanism is limited to dermal wound healing, although several diseases characterized by an exaggerated response to injury are prevalent in individuals of African ancestry. We have observed a complex pattern of phenotypic differences in keloid fibroblasts grown in standard culture medium or induced by hydrocortisone. In this study Affymetrix-based microarray was performed on RNA obtained from fibroblasts cultured from normal scars and keloids grown in the absence and presence of hydrocortisone. We observed differential regulation of approximately 500 genes of the 38,000 represented on the Affymetrix chip. Of particular interest was increased expression of several IGF-binding and IGF-binding related proteins and decreased expression of a subset of Wnt pathway inhibitors and multiple IL-1-inducible genes. Increased expression of CTGF and IGFBP-3 was observed in keloid fibroblasts only in the presence of hydrocortisone. These findings support a role for multiple fibrosis-related pathways in the pathogenesis of keloids. PMID:17989729

Smith, Joan C.; Boone, Braden E.; Opalenik, Susan R.; Williams, Scott M.; Russell, Shirley B.

2010-01-01

103

Serum Metabolomic Profiling in Acute Alcoholic Hepatitis Identifies Multiple Dysregulated Pathways  

PubMed Central

Background and Objectives While animal studies have implicated derangements of global energy homeostasis in the pathogenesis of acute alcoholic hepatitis (AAH), the relevance of these findings to the development of human AAH remains unclear. Using global, unbiased serum metabolomics analysis, we sought to characterize alterations in metabolic pathways associated with severe AAH and identify potential biomarkers for disease prognosis. Methods This prospective, case-control study design included 25 patients with severe AAH and 25 ambulatory patients with alcoholic cirrhosis. Serum samples were collected within 24 hours of the index clinical encounter. Global, unbiased metabolomics profiling was performed. Patients were followed for 180 days after enrollment to determine survival. Results Levels of 234 biochemicals were altered in subjects with severe AAH. Random-forest analysis, principal component analysis, and integrated hierarchical clustering methods demonstrated that metabolomics profiles separated the two cohorts with 100% accuracy. Severe AAH was associated with enhanced triglyceride lipolysis, impaired mitochondrial fatty acid beta oxidation, and upregulated omega oxidation. Low levels of multiple lysolipids and related metabolites suggested decreased plasma membrane remodeling in severe AAH. While most measured bile acids were increased in severe AAH, low deoxycholate and glycodeoxycholate levels indicated intestinal dysbiosis. Several changes in substrate utilization for energy homeostasis were identified in severe AAH, including increased glucose consumption by the pentose phosphate pathway, altered tricarboxylic acid (TCA) cycle activity, and enhanced peptide catabolism. Finally, altered levels of small molecules related to glutathione metabolism and antioxidant vitamin depletion were observed in patients with severe AAH. Univariable logistic regression revealed 15 metabolites associated with 180-day survival in severe AAH. Conclusion Severe AAH is characterized by a distinct metabolic phenotype spanning multiple pathways. Metabolomics profiling revealed a panel of biomarkers for disease prognosis, and future studies are planned to validate these findings in larger cohorts of patients with severe AAH. PMID:25461442

Rachakonda, Vikrant; Gabbert, Charles; Raina, Amit; Bell, Lauren N.; Cooper, Sara; Malik, Shahid; Behari, Jaideep

2014-01-01

104

Multiple pathways in the FGF signaling network are frequently deregulated by gene amplification in oral dysplasias  

PubMed Central

Genetic alteration in oral premalignant lesions (OPLs), the precursors of oral squamous cell carcinomas (OSCCs), may represent key changes in disease initiation and development. We ask if DNA amplification occurs at this early stage of cancer development and which oncogenic pathways are disrupted in OPLs. Here we evaluated 50 high-grade dysplasias and low-grade dysplasias that later progressed to cancer for gene dosage aberrations using tiling-path DNA microarrays. Early occurrences of DNA amplification and homozygous deletion were frequently detected, with 40% (20/50) of these early lesions exhibiting such features. Expression for 88 genes in seven recurrent amplicons were evaluated in five independent head and neck cancer datasets, with 40 candidates found to be overexpressed relative to normal tissues. These genes were significantly enriched in the canonical ERK/MAPK, FGF, p53, PTEN, and PI3K/AKT signaling pathways (P = 8.95x10-3--3.18×10-2). These identified pathways share interactions in one signaling network, and amplification-mediated deregulation of this network was found in 30.0% of these preinvasive lesions. No such alterations were found in 14 low-grade dysplasias that did not progress, while 43.5% (10/23) of OSCCs were found to have altered genes within the pathways with DNA amplification. Multi-target FISH showed that amplification of EGFR and CCND1 can co-exist in single cells of an oral dysplasia, suggesting the dependence on multiple oncogenes for OPL progression. Taken together, these findings identify a critical biological network that is frequently disrupted in high-risk OPLs, with different specific genes disrupted in different individuals. PMID:19623652

Tsui, Ivy F.L.; Poh, Catherine F.; Garnis, Cathie; Rosin, Miriam P.; Zhang, Lewei; Lam, Wan L.

2009-01-01

105

Requirements of the cytosolic iron–sulfur cluster assembly pathway in Arabidopsis  

PubMed Central

The assembly of iron–sulfur (Fe–S) clusters requires dedicated protein factors inside the living cell. Striking similarities between prokaryotic and eukaryotic assembly proteins suggest that plant cells inherited two different pathways through endosymbiosis: the ISC pathway in mitochondria and the SUF pathway in plastids. Fe–S proteins are also found in the cytosol and nucleus, but little is known about how they are assembled in plant cells. Here, we show that neither plastid assembly proteins nor the cytosolic cysteine desulfurase ABA3 are required for the activity of cytosolic aconitase, which depends on a [4Fe–4S] cluster. In contrast, cytosolic aconitase activity depended on the mitochondrial cysteine desulfurase NFS1 and the mitochondrial transporter ATM3. In addition, we were able to complement a yeast mutant in the cytosolic Fe–S cluster assembly pathway, dre2, with the Arabidopsis homologue AtDRE2, but only when expressed together with the diflavin reductase AtTAH18. Spectroscopic characterization showed that purified AtDRE2 could bind up to two Fe–S clusters. Purified AtTAH18 bound one flavin per molecule and was able to accept electrons from NAD(P)H. These results suggest that the proteins involved in cytosolic Fe–S cluster assembly are highly conserved, and that dependence on the mitochondria arose before the second endosymbiosis event leading to plastids. PMID:23754812

Bernard, Delphine G.; Netz, Daili J. A.; Lagny, Thibaut J.; Pierik, Antonio J.; Balk, Janneke

2013-01-01

106

Beclin 1 Is Required for Neuron Viability and Regulates Endosome Pathways via the UVRAG-VPS34 Complex  

PubMed Central

Deficiency of autophagy protein beclin 1 is implicated in tumorigenesis and neurodegenerative diseases, but the molecular mechanism remains elusive. Previous studies showed that Beclin 1 coordinates the assembly of multiple VPS34 complexes whose distinct phosphatidylinositol 3-kinase III (PI3K-III) lipid kinase activities regulate autophagy at different steps. Recent evidence suggests a function of beclin 1 in regulating multiple VPS34-mediated trafficking pathways beyond autophagy; however, the precise role of beclin 1 in autophagy-independent cellular functions remains poorly understood. Herein we report that beclin 1 regulates endocytosis, in addition to autophagy, and is required for neuron viability in vivo. We find that neuronal beclin 1 associates with endosomes and regulates EEA1/early endosome localization and late endosome formation. Beclin 1 maintains proper cellular phosphatidylinositol 3-phosphate (PI(3)P) distribution and total levels, and loss of beclin 1 causes a disruption of active Rab5 GTPase-associated endosome formation and impairment of endosome maturation, likely due to a failure of Rab5 to recruit VPS34. Furthermore, we find that Beclin 1 deficiency causes complete loss of the UVRAG-VPS34 complex and associated lipid kinase activity. Interestingly, beclin 1 deficiency impairs p40phox-linked endosome formation, which is rescued by overexpressed UVRAG or beclin 1, but not by a coiled-coil domain-truncated beclin 1 (a UVRAG-binding mutant), Atg14L or RUBICON. Thus, our study reveals the essential role for beclin 1 in neuron survival involving multiple membrane trafficking pathways including endocytosis and autophagy, and suggests that the UVRAG-beclin 1 interaction underlies beclin 1's function in endocytosis. PMID:25275521

Wold, Mitchell S.; Gong, Shiaoching; Phillips, Greg R.; Dou, Zhixun; Zhao, Yanxiang; Heintz, Nathaniel; Zong, Wei-Xing; Yue, Zhenyu

2014-01-01

107

ADI1, a methionine salvage pathway enzyme, is required for Drosophila fecundity  

PubMed Central

Background Methionine, an essential amino acid, is required for protein synthesis and normal cell metabolism. The transmethylation pathway and methionine salvage pathway (MTA cycle) are two major pathways regulating methionine metabolism. Recently, methionine has been reported to play a key role in Drosophila fecundity. Results Here, we revealed that the MTA cycle plays a crucial role in Drosophila fecundity using the mutant of aci-reductone dioxygenase 1 (DADI1), an enzyme in the MTA cycle. In dietary restriction condition, the egg production of adi1 mutant flies was reduced compared to that of control flies. This fecundity defect in mutant flies was rescued by reintroduction of Dadi1 gene. Moreover, a functional homolog of human ADI1 also recovered the reproduction defect, in which the enzymatic activity of human ADI1 is required for normal fecundity. Importantly, methionine supply rescued the fecundity defect in Dadi1 mutant flies. The detailed analysis of Dadi1 mutant ovaries revealed a dramatic change in the levels of methionine metabolism. In addition, we found that three compounds namely, methionine, SAM and Methionine sulfoxide, respectively, may be required for normal fecundity. Conclusions In summary, these results suggest that ADI1, an MTA cycle enzyme, affects fly fecundity through the regulation of methionine metabolism. PMID:25037729

2014-01-01

108

The MDM2-p53 pathway: multiple roles in kidney development.  

PubMed

The molecular basis of nephron progenitor cell renewal and differentiation into nascent epithelial nephrons is an area of intense investigation. Defects in these early stages of nephrogenesis lead to renal hypoplasia, and eventually hypertension and chronic kidney disease. Terminal nephron differentiation, the process by which renal epithelial precursor cells exit the cell cycle and acquire physiological functions is equally important. Failure of terminal epithelial cell differentiation results in renal dysplasia and cystogenesis. Thus, a better understanding of the transcriptional frameworks that regulate early and late renal cell differentiation is of great clinical significance. In this review, we will discuss evidence implicating the MDM2-p53 pathway in cell fate determination during development. The emerging central theme from loss- and gain-of-function studies is that tight regulation of p53 levels and transcriptional activity is absolutely required for nephrogenesis. We will also discuss how post-translational modifications of p53 (e.g., acetylation and phosphorylation) alter the spatiotemporal and functional properties of p53 and thus cell fate during kidney development. Mutations and polymorphisms in the MDM2-p53 pathway are present in more than 50 % of cancers in humans. This raises the question of whether sequence variants in the MDM2-p53 pathway increase the susceptibility to renal dysgenesis, hypertension or chronic kidney disease. With the advent of whole exome sequencing and other high throughput technologies, this hypothesis is testable in cohorts of children with renal dysgenesis. PMID:24077661

El-Dahr, Samir; Hilliard, Sylvia; Aboudehen, Karam; Saifudeen, Zubaida

2014-04-01

109

Towards a Multiple Ontology Framework for Requirements Elicitation and Reuse  

Microsoft Academic Search

In order to elicit system requirements correctly and unambiguously, researchers in the requirements engineering community have been studying and developing a number of ontology based approaches. Many of them adopt the single ontology schema, which utilizes a global ontology to describe static knowledge for all domains. However, such ontologies lack dynamic conceptual description and they are difficult to reuse. Based

Zong-yong Li; Zhi-xue Wang; Ying-ying Yang; Yue Wu; Ying Liu

2007-01-01

110

Multiple pathways to identification: exploring the multidimensionality of academic identity formation in ethnic minority males.  

PubMed

Empirical trends denote the academic underachievement of ethnic minority males across various academic domains. Identity-based explanations for this persistent phenomenon describe ethnic minority males as disidentified with academics, alienated, and oppositional. The present work interrogates these theoretical explanations and empirically substantiates a multidimensional lens for discussing academic identity formation within 330 African American and Latino early-adolescent males. Both hierarchical and iterative person-centered methods were utilized and reveal 5 distinct profiles derived from 6 dimensions of academic identity. These profiles predict self-reported classroom grades, mastery orientation, and self-handicapping in meaningful and varied ways. The results demonstrate multiple pathways to motivation and achievement, challenging previous oversimplified stereotypes of marginalized males. This exploratory study triangulates unique interpersonal and intrapersonal attributes for promoting healthy identity development and academic achievement among ethnic minority adolescent males. PMID:24447039

Matthews, Jamaal S

2014-04-01

111

The Afferent Visual Pathway: Designing a Structural-Functional Paradigm of Multiple Sclerosis  

PubMed Central

Multiple sclerosis (MS) is a disease of the central nervous system (CNS) believed to arise from a dysfunctional immune-mediated response in a genetically susceptible host. The actual cause of MS is not known, and there is ongoing debate about whether this CNS disorder is predominantly an inflammatory versus a degenerative condition. The afferent visual pathway (AVP) is frequently involved in MS, such that one in every five individuals affected presents with acute optic neuritis (ON). As a functionally eloquent system, the AVP is amenable to interrogation with highly reliable and reproducible tests that can be used to define a structural-functional paradigm of CNS injury. The AVP has numerous unique advantages as a clinical model of MS. In this review, the parameters and merits of the AVP model are highlighted. Moreover, the roles the AVP model may play in elucidating mechanisms of brain injury and repair in MS are described. PMID:24288622

Costello, Fiona

2013-01-01

112

Parasite infections in multiple sclerosis modulate immune responses through a retinoic acid-dependent pathway.  

PubMed

We recently demonstrated better outcomes in helminth-infected multiple sclerosis (MS) patients, compared with uninfected ones. The present study evaluates the role of TLR2 and retinoic acid (RA) in parasite-driven protection in MS patients. RA serum levels were significantly higher in helminth-infected MS patients than in uninfected MS subjects or healthy controls. Genes involved in RA biosynthesis and metabolism, such as Adh1 and Raldh2, as well as RA receptors and IL-10, were induced in dendritic cells (DCs) via TLR2-dependent ERK signaling. This programmed DCs to induce FOXP3(+) T regulatory cells and suppressed production of proinflammatory cytokines (IL-6, IL-12, IL-23, and TNF-?) via induction of suppressor of cytokine signaling 3 (SOCS3), an effect mediated by soluble egg Ag (SEA) obtained from Schistosoma mansoni, and by RA. SEA-activated DCs also inhibited IL-17 and IFN-? production through autoreactive T cells. These inhibitory effects were abrogated when SOCS3 gene expression was silenced, indicating that SEA-mediated signaling inhibited production of these cytokines by T cells, through a SOCS3-dependent pathway. Overall, helminth-related immunomodulation observed in MS patients was mediated by TLR2- and RA-dependent pathways, through two different mechanisms, as follows: 1) induction of IL-10 and FOXP3(+) T regulatory cells, and 2) suppression of proinflammatory cytokine production mediated by SOCS3. PMID:23975865

Correale, Jorge; Farez, Mauricio F

2013-10-01

113

Angiogenic activity of sesamin through the activation of multiple signal pathways  

SciTech Connect

The natural product sesamin has been known to act as a potent antioxidant and prevent endothelial dysfunction. We here found that sesamin increased in vitro angiogenic processes, such as endothelial cell proliferation, migration, and tube formation, as well as neovascularization in an animal model. This compound elicited the activation of multiple angiogenic signal modulators, such as ERK, Akt, endothelial nitric oxide synthase (eNOS), NO production, FAK, and p38 MAPK, but not Src. The MEK inhibitor PD98059 and the PI3K inhibitor Wortmannin specifically inhibited sesamin-induced activation of the ERK and Akt/eNOS pathways. These inhibitors reduced angiogenic events, with high specificity for MEK/ERK-dependent cell proliferation and migration and PI3K/Akt-mediated tube formation. Moreover, inhibition of p38 MAPK effectively inhibited sesamin-induced cell migration. The angiogenic activity of sesamin was not associated with VEGF expression. Furthermore, this compound did not induce vascular permeability and upregulated ICAM-1 and VCAM-1 expression, which are hallmarks of vascular inflammation. These results suggest that sesamin stimulates angiogenesis in vitro and in vivo through the activation of MEK/ERK-, PI3K/Akt/eNOS-, p125{sup FAK}-, and p38 MAPK-dependent pathways, without increasing vascular inflammation, and may be used for treating ischemic diseases and tissue regeneration.

Chung, Byung-Hee [Vascular System Research Center and Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon (Korea, Republic of) [Vascular System Research Center and Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon (Korea, Republic of); Division of Food Biotechnology, School of Biotechnology, Kangwon National University, Chuncheon (Korea, Republic of); Lee, Jung Joon [Center for Molecular Cancer Research, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of)] [Center for Molecular Cancer Research, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of); Kim, Jong-Dai [Division of Food Biotechnology, School of Biotechnology, Kangwon National University, Chuncheon (Korea, Republic of)] [Division of Food Biotechnology, School of Biotechnology, Kangwon National University, Chuncheon (Korea, Republic of); Jeoung, Dooil; Lee, Hansoo [Division of Life Sciences, Kangwon National University, Chuncheon (Korea, Republic of)] [Division of Life Sciences, Kangwon National University, Chuncheon (Korea, Republic of); Choe, Jongseon; Ha, Kwon-Soo [Vascular System Research Center and Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon (Korea, Republic of)] [Vascular System Research Center and Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon (Korea, Republic of); Kwon, Young-Geun [Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul (Korea, Republic of)] [Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul (Korea, Republic of); Kim, Young-Myeong, E-mail: ymkim@kangwon.ac.kr [Vascular System Research Center and Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon (Korea, Republic of)] [Vascular System Research Center and Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon (Korea, Republic of)

2010-01-01

114

The phosphatidylinositol 3' kinase pathway is required for the survival signal of leukocyte tyrosine kinase.  

PubMed

Leukocyte tyrosine kinase (LTK) is a receptor tyrosine kinase which belongs to the insulin receptor superfamily and is mainly expressed in pre-B lymphocytes and neuronal tissues. Recently, we demonstrated that LTK utilizes Shc and IRS-1 as two major substrates and while both equally activate the Ras pathway, only IRS-1 suppresses apoptosis of hematopoietic cells, suggesting the existence of another unidentified signaling pathway downstream of IRS-1, which is relevant to the anti-apoptotic activity. In the present study, we found that wortmannin, a specific inhibitor of phosphatidylinositol 3' (PI3)-kinase, abolished the survival effects of LTK. Although c-Cbl is found to be phosphorylated by LTK and therefore is a second candidate linking LTK with the PI3-kinase pathway along with IRS-1, we found that the p85 subunit of PI3 kinase directly binds to tyrosine 753 of LTK, which is located within a YXXM motif, a consensus binding amino acid sequence for the SH2 domain of p85, but fails to bind to IRS-1 or c-Cbl. Ba/F3 cells which stably express the EGF receptor-LTK chimeric receptor carrying a mutation at tyrosine 753 fell into apoptotic death even in the presence of EGF, indicating that the PI3 kinase pathway is required for the survival effects of LTK. PMID:9223670

Ueno, H; Honda, H; Nakamoto, T; Yamagata, T; Sasaki, K; Miyagawa, K; Mitani, K; Yazaki, Y; Hirai, H

1997-06-26

115

Multiple signal transduction pathways regulate discoidin I gene expression in Dictyostelium discoideum.  

PubMed

The expression of the discoidin I genes in Dictyostelium discoideum is regulated by the concerted action of the extracellular factors cyclic adenosine monophosphate (cAMP), folate, prestarvation factor (PSF) and conditioned media factor (CMF). However, the pathways by which these signals are transduced and the interactions between the pathways have been unexplored so far. We have analysed wild-type and mutant cells with defined lesions in signal transduction to elucidate these regulatory processes, and shown that different pathways are used for the down-regulation and induction of these genes. The cAMP receptor cARI is required for the cAMP-mediated down-regulation of discoidin I gene expression but not for the induction of discoidin I expression during development. Surprisingly, induction of the discoidin I genes requires G alpha 2, the G-protein subunit which is generally believed to couple to cARI, to control the expression of cAMP-inducible genes. Thus, our data suggest that G alpha 2 interacts with different receptors to regulate gene expression in early development. Furthermore, the analysis shows that discoidin induction in bacterially grown cells occurs in two sequential steps. The first is a low basal induction which occurs in late log-phase growth prior to starvation. PSF can induce the basal level, and the induction is independent of G alpha 2. The developmental induction following starvation is much stronger, dependent on G alpha 2 and probably signaled by CMF, which is secreted at that time.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7641976

Blusch, J; Alexander, S; Nellen, W

1995-04-01

116

Family Histories and Multiple Transitions Among Homeless Young Adults: Pathways to Homelessness  

PubMed Central

This study explored the early family histories of homeless young adults, the types and number of transitions they experienced, and their pathways to the street. Intensive qualitative interviews were audio taped and transcribed with 40 homeless young adults 19 to 21 years of age in the Midwest. Findings show that family backgrounds were generally characterized by substance use, child maltreatment, and witnessing violence, all of which provide social context for understanding why so many of these young people opted to leave home in search of an alternative living situation. The current findings also reveal that while some young adults ran away from home as adolescents, others were “pushed out” (i.e., told to leave), or removed by state agencies. Current study findings illustrate that young adults’ trajectories are marked by multiple living arrangements such as home, foster care, detention facility, and drug rehabilitation. Overall, study results show that young adults’ family histories place them on trajectories for early independence marked by multiple transitions and numerous living situations, culminating in a lack of a permanent residence to call home. PMID:24151346

Tyler, Kimberly A.; Schmitz, Rachel M.

2013-01-01

117

Family Histories and Multiple Transitions Among Homeless Young Adults: Pathways to Homelessness.  

PubMed

This study explored the early family histories of homeless young adults, the types and number of transitions they experienced, and their pathways to the street. Intensive qualitative interviews were audio taped and transcribed with 40 homeless young adults 19 to 21 years of age in the Midwest. Findings show that family backgrounds were generally characterized by substance use, child maltreatment, and witnessing violence, all of which provide social context for understanding why so many of these young people opted to leave home in search of an alternative living situation. The current findings also reveal that while some young adults ran away from home as adolescents, others were "pushed out" (i.e., told to leave), or removed by state agencies. Current study findings illustrate that young adults' trajectories are marked by multiple living arrangements such as home, foster care, detention facility, and drug rehabilitation. Overall, study results show that young adults' family histories place them on trajectories for early independence marked by multiple transitions and numerous living situations, culminating in a lack of a permanent residence to call home. PMID:24151346

Tyler, Kimberly A; Schmitz, Rachel M

2013-10-01

118

Aryl hydrocarbon receptor knock-out exacerbates choroidal neovascularization via multiple pathogenic pathways  

PubMed Central

The aryl hydrocarbon receptor (AhR) is a heterodimeric transcriptional regulator with pleiotropic functions in xenobiotic metabolism and detoxification, vascular development and cancer. Herein, we report a previously undescribed role for the AhR signalling pathway in the pathogenesis of the wet, neovascular subtype of age-related macular degeneration (AMD), the leading cause of vision loss in the elderly in the Western world. Comparative analysis of gene expression profiles of aged AhR?/? and wild-type (wt) mice, using high-throughput RNA sequencing, revealed differential modulation of genes belonging to several AMD-related pathogenic pathways, including inflammation, angiogenesis and extracellular matrix regulation. To investigate AhR regulation of these pathways in wet AMD, we experimentally induced choroidal neovascular lesions in AhR?/? mice and found that they measured significantly larger in area and volume compared to age-matched wt mice. Furthermore, these lesions displayed a higher number of ionized calcium-binding adaptor molecule 1-positive (Iba1+) microglial cells and a greater amount of collagen type IV deposition, events also seen in human wet AMD pathology specimens. Consistent with our in vivo observations, AhR knock-down was sufficient to increase choroidal endothelial cell migration and tube formation in vitro. Moreover, AhR knock-down caused an increase in collagen type IV production and secretion in both retinal pigment epithelial (RPE) and choroidal endothelial cell cultures, increased expression of angiogenic and inflammatory molecules, including vascular endothelial growth factor A (VEGFA) and chemokine (C–C motif) ligand 2 (CCL2) in RPE cells, and increased expression of secreted phosphoprotein 1 (SPP1) and transforming growth factor-?1 (TGF?1) in choroidal endothelial cells. Collectively, our findings identify AhR as a regulator of multiple pathogenic pathways in experimentally induced choroidal neovascularization, findings that are consistent with a possible role of AhR in wet AMD. The data discussed in this paper have been deposited in NCBI's Gene Expression Omnibus; GEO Submission No. GSE56983, NCBI Tracking System No. 17021116. PMID:25186463

Choudhary, Mayur; Kazmin, Dmitri; Hu, Peng; Thomas, Russell S; McDonnell, Donald P; Malek, Goldis

2015-01-01

119

Aryl hydrocarbon receptor knock-out exacerbates choroidal neovascularization via multiple pathogenic pathways.  

PubMed

The aryl hydrocarbon receptor (AhR) is a heterodimeric transcriptional regulator with pleiotropic functions in xenobiotic metabolism and detoxification, vascular development and cancer. Herein, we report a previously undescribed role for the AhR signalling pathway in the pathogenesis of the wet, neovascular subtype of age-related macular degeneration (AMD), the leading cause of vision loss in the elderly in the Western world. Comparative analysis of gene expression profiles of aged AhR(-/-) and wild-type (wt) mice, using high-throughput RNA sequencing, revealed differential modulation of genes belonging to several AMD-related pathogenic pathways, including inflammation, angiogenesis and extracellular matrix regulation. To investigate AhR regulation of these pathways in wet AMD, we experimentally induced choroidal neovascular lesions in AhR(-/-) mice and found that they measured significantly larger in area and volume compared to age-matched wt mice. Furthermore, these lesions displayed a higher number of ionized calcium-binding adaptor molecule 1-positive (Iba1(+) ) microglial cells and a greater amount of collagen type IV deposition, events also seen in human wet AMD pathology specimens. Consistent with our in vivo observations, AhR knock-down was sufficient to increase choroidal endothelial cell migration and tube formation in vitro. Moreover, AhR knock-down caused an increase in collagen type IV production and secretion in both retinal pigment epithelial (RPE) and choroidal endothelial cell cultures, increased expression of angiogenic and inflammatory molecules, including vascular endothelial growth factor A (VEGFA) and chemokine (C-C motif) ligand 2 (CCL2) in RPE cells, and increased expression of secreted phosphoprotein 1 (SPP1) and transforming growth factor-?1 (TGF?1) in choroidal endothelial cells. Collectively, our findings identify AhR as a regulator of multiple pathogenic pathways in experimentally induced choroidal neovascularization, findings that are consistent with a possible role of AhR in wet AMD. The data discussed in this paper have been deposited in NCBI's Gene Expression Omnibus; GEO Submission No. GSE56983, NCBI Tracking System No. 17021116. PMID:25186463

Choudhary, Mayur; Kazmin, Dmitri; Hu, Peng; Thomas, Russell S; McDonnell, Donald P; Malek, Goldis

2015-01-01

120

The major cellular sterol regulatory pathway is required for Andes virus infection.  

PubMed

The Bunyaviridae comprise a large family of RNA viruses with worldwide distribution and includes the pathogenic New World hantavirus, Andes virus (ANDV). Host factors needed for hantavirus entry remain largely enigmatic and therapeutics are unavailable. To identify cellular requirements for ANDV infection, we performed two parallel genetic screens. Analysis of a large library of insertionally mutagenized human haploid cells and a siRNA genomic screen converged on components (SREBP-2, SCAP, S1P and S2P) of the sterol regulatory pathway as critically important for infection by ANDV. The significance of this pathway was confirmed using functionally deficient cells, TALEN-mediated gene disruption, RNA interference and pharmacologic inhibition. Disruption of sterol regulatory complex function impaired ANDV internalization without affecting virus binding. Pharmacologic manipulation of cholesterol levels demonstrated that ANDV entry is sensitive to changes in cellular cholesterol and raises the possibility that clinically approved regulators of sterol synthesis may prove useful for combating ANDV infection. PMID:24516383

Petersen, Josiah; Drake, Mary Jane; Bruce, Emily A; Riblett, Amber M; Didigu, Chukwuka A; Wilen, Craig B; Malani, Nirav; Male, Frances; Lee, Fang-Hua; Bushman, Frederic D; Cherry, Sara; Doms, Robert W; Bates, Paul; Briley, Kenneth

2014-02-01

121

Oncogenesis driven by the Ras/Raf pathway requires the SUMO E2 ligase Ubc9.  

PubMed

The small GTPase KRAS is frequently mutated in human cancer and currently there are no targeted therapies for KRAS mutant tumors. Here, we show that the small ubiquitin-like modifier (SUMO) pathway is required for KRAS-driven transformation. RNAi depletion of the SUMO E2 ligase Ubc9 suppresses 3D growth of KRAS mutant colorectal cancer cells in vitro and attenuates tumor growth in vivo. In KRAS mutant cells, a subset of proteins exhibit elevated levels of SUMOylation. Among these proteins, KAP1, CHD1, and EIF3L collectively support anchorage-independent growth, and the SUMOylation of KAP1 is necessary for its activity in this context. Thus, the SUMO pathway critically contributes to the transformed phenotype of KRAS mutant cells and Ubc9 presents a potential target for the treatment of KRAS mutant colorectal cancer. PMID:25805818

Yu, Bing; Swatkoski, Stephen; Holly, Alesia; Lee, Liam C; Giroux, Valentin; Lee, Chih-Shia; Hsu, Dennis; Smith, Jordan L; Yuen, Garmen; Yue, Junqiu; Ann, David K; Simpson, R Mark; Creighton, Chad J; Figg, William D; Gucek, Marjan; Luo, Ji

2015-04-01

122

The Major Cellular Sterol Regulatory Pathway Is Required for Andes Virus Infection  

PubMed Central

The Bunyaviridae comprise a large family of RNA viruses with worldwide distribution and includes the pathogenic New World hantavirus, Andes virus (ANDV). Host factors needed for hantavirus entry remain largely enigmatic and therapeutics are unavailable. To identify cellular requirements for ANDV infection, we performed two parallel genetic screens. Analysis of a large library of insertionally mutagenized human haploid cells and a siRNA genomic screen converged on components (SREBP-2, SCAP, S1P and S2P) of the sterol regulatory pathway as critically important for infection by ANDV. The significance of this pathway was confirmed using functionally deficient cells, TALEN-mediated gene disruption, RNA interference and pharmacologic inhibition. Disruption of sterol regulatory complex function impaired ANDV internalization without affecting virus binding. Pharmacologic manipulation of cholesterol levels demonstrated that ANDV entry is sensitive to changes in cellular cholesterol and raises the possibility that clinically approved regulators of sterol synthesis may prove useful for combating ANDV infection. PMID:24516383

Riblett, Amber M.; Didigu, Chukwuka A.; Wilen, Craig B.; Malani, Nirav; Male, Frances; Lee, Fang-Hua; Bushman, Frederic D.; Cherry, Sara; Doms, Robert W.; Bates, Paul; Briley, Kenneth

2014-01-01

123

Multiple Functions of Let-23, a Caenorhabditis Elegans Receptor Tyrosine Kinase Gene Required for Vulval Induction  

PubMed Central

The let-23 gene, which encodes a putative tyrosine kinase of the epidermal growth factor (EGF) receptor subfamily, has multiple functions during Caenorhabditis elegans development. We show that let-23 function is required for vulval precursor cells (VPCs) to respond to the signal that induces vulval differentiation: a complete loss of let-23 function results in no induction. However, some let-23 mutations that genetically reduce but do not eliminate let-23 function result in VPCs apparently hypersensitive to inductive signal: as many as five of six VPCs can adopt vulval fates, in contrast to the three that normally do. These results suggest that the let-23 receptor tyrosine kinase controls two opposing pathways, one that stimulates vulval differentiation and another that negatively regulates vulval differentiation. Furthermore, analysis of 16 new let-23 mutations indicates that the let-23 kinase functions in at least five tissues. Since various let-23 mutant phenotypes can be obtained independently, the let-23 gene is likely to have tissue-specific functions. PMID:2071015

Aroian, R. V.; Sternberg, P. W.

1991-01-01

124

Displacements required during multiple drapefolding along the northwest Bighorn Mountain front, Wyoming  

E-print Network

of the requirement for the degree of . MASTER OF SCIE1'ICE May 19'78 Major Subject: Geology DISPLACHMHNTS REQUIRED DURING MULTIPLE DRAPE-FOLDING ALONG THE NORTHWEST BIGHORN MiOUNTAIN FRONT, WYOMING A Thesis by MARTHA MARGARET TIREY Approved as to style end... content by: Chazrma oi' ommmttee mbe= Member May 1978 442'998 ABSTRACT Displacements required during multiple drape-folding along the Northwest Bighorn Mountain Front, Wyoming (Nay 1978) Martha Margaret Tirey, B. S, , Texas ASM University...

Tirey, Martha Margaret

1978-01-01

125

Isoprenoid biosynthetic pathway inhibition disrupts monoclonal protein secretion and induces the unfolded protein response pathway in multiple myeloma cells  

PubMed Central

Myeloma is characterized by the overproduction and secretion of monoclonal protein. Inhibitors of the isoprenoid biosynthetic pathway (IBP) have pleiotropic effects in myeloma cells. To investigate whether IBP inhibition interferes with monoclonal protein secretion, human myeloma cells were treated with specific inhibitors of the IBP or prenyltransferases. These studies demonstrate that agents that inhibit Rab geranylgeranylation disrupt light chain trafficking, lead to accumulation of light chain in the endoplasmic reticulum, activate the unfolded protein response pathway and induce apoptosis. These studies provide a novel mechanism of action for IBP inhibitors and suggest that further exploration of Rab-targeted agents in myeloma is warranted. PMID:20828814

Holstein, Sarah A.; Hohl, Raymond J.

2010-01-01

126

Transcriptional profiling suggests that multiple metabolic adaptations are required for effective proliferation of Pseudomonas aeruginosa in jet fuel.  

PubMed

Fuel is a harsh environment for microbial growth. However, some bacteria can grow well due to their adaptive mechanisms. Our goal was to characterize the adaptations required for Pseudomonas aeruginosa proliferation in fuel. We have used DNA-microarrays and RT-PCR to characterize the transcriptional response of P. aeruginosa to fuel. Transcriptomics revealed that genes essential for medium- and long-chain n-alkane degradation including alkB1 and alkB2 were transcriptionally induced. Gas chromatography confirmed that P. aeruginosa possesses pathways to degrade different length n-alkanes, favoring the use of n-C11-18. Furthermore, a gamut of synergistic metabolic pathways, including porins, efflux pumps, biofilm formation, and iron transport, were transcriptionally regulated. Bioassays confirmed that efflux pumps and biofilm formation were required for growth in jet fuel. Furthermore, cell homeostasis appeared to be carefully maintained by the regulation of porins and efflux pumps. The Mex RND efflux pumps were required for fuel tolerance; blockage of these pumps precluded growth in fuel. This study provides a global understanding of the multiple metabolic adaptations required by bacteria for survival and proliferation in fuel-containing environments. This information can be applied to improve the fuel bioremediation properties of bacteria. PMID:24164330

Gunasekera, Thusitha S; Striebich, Richard C; Mueller, Susan S; Strobel, Ellen M; Ruiz, Oscar N

2013-12-01

127

Targeting NF-B pathway with an IKK2 inhibitor induces inhibition of multiple myeloma cell growth  

E-print Network

1 Targeting NF-B pathway with an IKK2 inhibitor induces inhibition of multiple myeloma cell growth derivative AS602868, on the in vitro growth of 14 human MM cell lines (HMCL) and primary cells from 13-dependent inhibition of MM cell growth, which is the result of a simultaneous induction of apoptosis and inhibition

Paris-Sud XI, Université de

128

Pathways targeted by antidiabetes drugs are enriched for multiple genes associated with type 2 diabetes risk.  

PubMed

Genome-wide association studies (GWAS) have uncovered >65 common variants associated with type 2 diabetes (T2D); however, their relevance for drug development is not yet clear. Of note, the first two T2D-associated loci (PPARG and KCNJ11/ABCC8) encode known targets of antidiabetes medications. We therefore tested whether other genes/pathways targeted by antidiabetes drugs are associated with T2D. We compiled a list of 102 genes in pathways targeted by marketed antidiabetic medications and applied Gene Set Enrichment Analysis (MAGENTA [Meta-Analysis Gene-set Enrichment of variaNT Associations]) to this gene set, using available GWAS meta-analyses for T2D and seven quantitative glycemic traits. We detected a strong enrichment of drug target genes associated with T2D (P = 2 × 10(-5); 14 potential new associations), primarily driven by insulin and thiazolidinedione (TZD) targets, which was replicated in an independent meta-analysis (Metabochip). The glycemic traits yielded no enrichment. The T2D enrichment signal was largely due to multiple genes of modest effects (P = 4 × 10(-4), after removing known loci), highlighting new associations for follow-up (ACSL1, NFKB1, SLC2A2, incretin targets). Furthermore, we found that TZD targets were enriched for LDL cholesterol associations, illustrating the utility of this approach in identifying potential side effects. These results highlight the potential biomedical relevance of genes revealed by GWAS and may provide new avenues for tailored therapy and T2D treatment design. PMID:25368101

Segrè, Ayellet V; Wei, Nancy; Altshuler, David; Florez, Jose C

2015-04-01

129

Multiple Forms of Plant Phosphoenolpyruvate Carboxylase Associated with Different Metabolic Pathways 1  

PubMed Central

The physical and kinetic properties of multiple forms of phosphoenolpyruvate carboxylase were studied in leaves of C4 and C3 species, their F1 and F3 hybrids, in greening maize leaves, in Crassulacean acid metabolism plants, and in nongreen root tissues. Four different forms are suggested: a C4 photosynthetic phosphoenolpyruvate carboxylase with high Km for phosphoenolpyruvate (?0.59 mm), Km Mg (?0.5 mm), and Vmax (?29 micromoles per minute per milligram of chlorophyll); a C3 photosynthetic phosphoenolpyruvate carboxylase with low Km for phosphoenolpyruvate (?0.14 mm), Km for Mg (?0.097 mm), and Vmax (1.5); a Crassulacean acid metabolism type with low Km for phosphoenolpyruvate (0.14 mm), and high Vmax (14 micromoles per minute per milligram of chlorophyll); and a nongreen or nonautotrophic type with low Km for phosphoenolpyruvate, Km for Mg, and low Vmax. In closely related species or within species, the types can be differentiated by anion exchange column chromatography. Each of the four forms is associated with a different metabolic pathway: the phosphoenolpyruvate carboxylase of C4 species for malate generation as a photosynthetic intermediate, the phosphoenolpyruvate carboxylase of C3 species in malate generation as a photosynthetic product, the phosphoenolpyruvate carboxylase of Crassulacean acid metabolism species in malate generation as a CO2 donor for photosynthesis during the subsequent light period, and a nongreen or root type producing malate for ionic balance and reduced nicotinamide adenine dinucleotide phosphate generation. The data in this paper in conjunction with published information support the notion of different molecular forms of a protein functioning in different metabolic pathways which have common enzymic steps. PMID:16658349

Ting, Irwin P.; Osmond, C. B.

1973-01-01

130

Ethylene signaling pathway and MAPK cascades are required for AAL toxin-induced programmed cell death.  

PubMed

Programmed cell death (PCD), known as hypersensitive response cell death, has an important role in plant defense response. The signaling pathway of PCD remains unknown. We employed AAL toxin and Nicotiana umbratica to analysis plant PCD. AAL toxin is a pathogenicity factor of the necrotrophic pathogen Alternaria alternata f. sp. lycopersici. N. umbratica is sensitive to AAL toxin, susceptible to pathogens, and effective in Tobacco rattle virus-based virus-induced gene silencing (VIGS). VIGS analyses indicated that AAL toxin-triggered cell death (ACD) is dependent upon the mitogen-activated protein (MAP) kinase kinase MEK2, which is upstream of both salicylic acid-induced protein kinase (SIPK) and wound-induced protein kinase (WIPK) responsible for ethylene (ET) synthesis. ET treatment of MEK2-silenced N. umbratica re-established ACD. In SIPK- and WIPK-silenced N. umbratica, ACD was compromised and ET accumulation was not observed. However, in contrast to the case of MEK2-silenced plants, ET treatment did not induce cell death in SIPK- and WIPK-silenced plants. This work showed that ET-dependent pathway and MAP kinase cascades are required in ACD. Our results suggested that MEK2-SIPK/WIPK cascades have roles in ET biosynthesis; however, SIPK and WIPK have other roles in ET signaling or another pathway leading to cell death by AAL toxin. PMID:22512379

Mase, Keisuke; Mizuno, Takahito; Ishihama, Nobuaki; Fujii, Takayuki; Mori, Hitoshi; Kodama, Motoichiro; Yoshioka, Hirofumi

2012-08-01

131

Effective use of a horizontally-transferred pathway for dichloromethane catabolism requires post–transfer refinement  

PubMed Central

When microbes acquire new abilities through horizontal gene transfer, the genes and pathways must function under conditions with which they did not coevolve. If newly-acquired genes burden the host, their utility will depend on further evolutionary refinement of the recombinant strain. We used laboratory evolution to recapitulate this process of transfer and refinement, demonstrating that effective use of an introduced dichloromethane degradation pathway required one of several mutations to the bacterial host that are predicted to increase chloride efflux. We then used this knowledge to identify parallel, beneficial mutations that independently evolved in two natural dichloromethane-degrading strains. Finally, we constructed a synthetic mobile genetic element carrying both the degradation pathway and a chloride exporter, which preempted the adaptive process and directly enabled effective dichloromethane degradation across diverse Methylobacterium environmental isolates. Our results demonstrate the importance of post–transfer refinement in horizontal gene transfer, with potential applications in bioremediation and synthetic biology. DOI: http://dx.doi.org/10.7554/eLife.04279.001 PMID:25418043

Michener, Joshua K; Camargo Neves, Aline A; Vuilleumier, Stéphane; Bringel, Françoise; Marx, Christopher J

2014-01-01

132

Efficient Herpes Simplex Virus 1 Replication Requires Cellular ATR Pathway Proteins  

PubMed Central

Herpes simplex virus 1 (HSV-1) is a double-stranded DNA virus that replicates in the nucleus of the host cell and is known to interact with several components of the cellular DNA-damage-signaling machinery. We have previously reported that the DNA damage response kinase, ATR, is specifically inactivated in HSV-1-infected cells. On the other hand, we have also shown that ATR and its scaffolding protein, ATRIP, are recruited to viral replication compartments, where they play beneficial roles during HSV-1 replication. In order to better understand this apparent discrepancy, we tested the hypothesis that some of the components of the ATR pathway may exert an antiviral effect on infection. In fact, we learned that all 10 of the canonical ATR pathway proteins are stable in HSV-infected cells and are recruited to viral replication compartments; furthermore, short hairpin RNA (shRNA) knockdown shows that several, including ATRIP, RPA70, TopBP1, Claspin, and CINP, are required for efficient HSV-1 replication. We also determined that activation of the ATR kinase prior to infection did not affect virus yield but did result in reduced levels of recombination between coinfecting viruses. Together, these data suggest that ATR pathway proteins are not antiviral per se but that activation of ATR signaling may have negative consequences during viral replication, such as inhibiting recombination. PMID:23097436

Mohni, Kareem N.; Dee, Alexander R.; Smith, Samantha; Schumacher, April J.

2013-01-01

133

Potential role of multiple carbon fixation pathways during lipid accumulation in Phaeodactylum tricornutum  

PubMed Central

Background Phaeodactylum tricornutum is a unicellular diatom in the class Bacillariophyceae. The full genome has been sequenced (<30?Mb), and approximately 20 to 30% triacylglyceride (TAG) accumulation on a dry cell basis has been reported under different growth conditions. To elucidate P. tricornutum gene expression profiles during nutrient-deprivation and lipid-accumulation, cell cultures were grown with a nitrate to phosphate ratio of 20:1 (N:P) and whole-genome transcripts were monitored over time via RNA-sequence determination. Results The specific Nile Red (NR) fluorescence (NR fluorescence per cell) increased over time; however, the increase in NR fluorescence was initiated before external nitrate was completely exhausted. Exogenous phosphate was depleted before nitrate, and these results indicated that the depletion of exogenous phosphate might be an early trigger for lipid accumulation that is magnified upon nitrate depletion. As expected, many of the genes associated with nitrate and phosphate utilization were up-expressed. The diatom-specific cyclins cyc7 and cyc10 were down-expressed during the nutrient-deplete state, and cyclin B1 was up-expressed during lipid-accumulation after growth cessation. While many of the genes associated with the C3 pathway for photosynthetic carbon reduction were not significantly altered, genes involved in a putative C4 pathway for photosynthetic carbon assimilation were up-expressed as the cells depleted nitrate, phosphate, and exogenous dissolved inorganic carbon (DIC) levels. P. tricornutum has multiple, putative carbonic anhydrases, but only two were significantly up-expressed (2-fold and 4-fold) at the last time point when exogenous DIC levels had increased after the cessation of growth. Alternative pathways that could utilize HCO3- were also suggested by the gene expression profiles (e.g., putative propionyl-CoA and methylmalonyl-CoA decarboxylases). Conclusions The results indicate that P. tricornutum continued carbon dioxide reduction when population growth was arrested and different carbon-concentrating mechanisms were used dependent upon exogenous DIC levels. Based upon overall low gene expression levels for fatty acid synthesis, the results also suggest that the build-up of precursors to the acetyl-CoA carboxylases may play a more significant role in TAG synthesis rather than the actual enzyme levels of acetyl-CoA carboxylases per se. The presented insights into the types and timing of cellular responses to inorganic carbon will help maximize photoautotrophic carbon flow to lipid accumulation. PMID:22672912

2012-01-01

134

Application of Multidimensional Selective Item Response Regression Model for Studying Multiple Gene Methylation in SV40 Oncogenic Pathways  

PubMed Central

Alteration of gene methylation patterns has been reported to be involved in the early onsets of many human malignancies. Many exogenous risk factors, such as cigarette smoke, dietary additives, chemical exposures, radiation, and biologic agents including viral infection, are involved in the methylation pathways of cancers. We propose a multidimensional selective item response regression model to describe and test how a risk factor may alter molecular pathways involving aberrant methylation of multiple genes in oncogenesis. Our modeling framework is built on an item response model for multivariate dichotomous responses of high dimension, such as aberrant methylation of multiple tumor-suppressor genes, but we allow risk factors such as SV40 viral infection to alter the distribution of the latent factors that subsequently affect the outcome of cancer. We postulate empirical identification conditions under our model formulation. Moreover, we do not prespecify the links between the multiple dichotomous methylation responses and the latent factors, but rather conduct specification searches with a genetic algorithm to discover the links. Parameter estimation through maximum likelihood and specification searches in models with multidimensional latent factors for multivariate binary responses have become practical only recently, due to modern statistical computing development. We illustrate our proposal with the biological finding that simultaneous methylation of multiple tumor-suppressor genes is associated with the presence of SV40 viral sequences and with the cancer status of lymphoma/leukemia.We are able to test whether the data are consistent with the causal hypothesis that SV40 induces aberrant methylation of multiple genes in its oncogenic pathways. At the same time, we are able to evaluate the role of SV40 in the methylation pathway and to determine whether the methylation pathway is responsible for the development of leukemia/lymphoma. PMID:19830254

Lin, Haiqun; Feng, Ziding; Yu, Yan; Zheng, Yingye; Shivapurkar, Narayan; Gazdar, Adi F.

2009-01-01

135

Multiple gustatory receptors required for the caffeine response in Drosophila.  

PubMed

The ability of insects to detect and avoid ingesting naturally occurring repellents and insecticides is essential for their survival. Nevertheless, the gustatory receptors enabling them to sense toxic botanical compounds are largely unknown. The only insect gustatory receptor shown to be required for avoiding noxious compounds is the Drosophila caffeine receptor, Gr66a. However, this receptor is not sufficient for the caffeine response, suggesting that Gr66a may be a subunit of a larger receptor. Here, we report that mutations in the gene encoding the gustatory receptor, Gr93a, result in a phenotype identical to that caused by mutations in Gr66a. This includes an inability to avoid caffeine or the related methylxanthine present in tea, theophylline. Caffeine-induced action potentials were also eliminated in Gr93a-mutant animals, while the flies displayed normal responses to other aversive compounds or to sugars. The Gr93a protein was coexpressed with Gr66a in avoidance-gustatory receptor neurons (GRNs), and functioned in the same GRNs as Gr66a. However, misexpression of both receptors in GRNs that normally do not express either Gr93a or Gr66a does not confer caffeine sensitivity to these GRNs. Because Gr93a- and Gr66a-mutant animals exhibit the identical phenotypes and function in the same cells, we propose that they may be caffeine coreceptors. In contrast to mammalian and Drosophila olfactory receptors and mammalian taste receptors, which are monomeric or dimeric receptors, we propose that Drosophila taste receptors that function in avoidance of bitter compounds are more complex and require additional subunits that remain to be identified. PMID:19246397

Lee, Youngseok; Moon, Seok Jun; Montell, Craig

2009-03-17

136

40 CFR 63.1356 - Sources with multiple emission limits or monitoring requirements.  

Code of Federal Regulations, 2011 CFR

...FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry Other § 63.1356 Sources with multiple emission limits or monitoring requirements....

2011-07-01

137

40 CFR 63.1356 - Sources with multiple emissions limit or monitoring requirements.  

Code of Federal Regulations, 2013 CFR

...AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry Other § 63.1356 Sources with multiple emissions limit or monitoring requirements....

2013-07-01

138

40 CFR 63.1356 - Sources with multiple emission limits or monitoring requirements.  

Code of Federal Regulations, 2012 CFR

...FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry Other § 63.1356 Sources with multiple emission limits or monitoring requirements....

2012-07-01

139

40 CFR 63.1356 - Sources with multiple emissions limit or monitoring requirements.  

Code of Federal Regulations, 2014 CFR

...AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry Other § 63.1356 Sources with multiple emissions limit or monitoring requirements....

2014-07-01

140

Theoretical tracking of resonance-enhanced multiple ionization pathways in X-ray free-electron laser pulses.  

PubMed

We present an extended Monte Carlo rate equation approach to examine the inner-shell ionization dynamics of atoms in an intense x-ray free-electron laser (XFEL) pulse. In addition to photoionization, Auger decay, and fluorescence processes, we include bound-to-bound transitions in the rate equation calculations. Using an efficient computational scheme, we account for "hidden resonances" unveiled during the course of an XFEL pulse. For Ar, the number of possible electron configurations is increased ten-billion-fold over that required under nonresonant conditions. We investigated the complex ionization dynamics of Ar atoms exposed to an 480-eV XFEL pulse, where production of ions above charge state 10+ is not allowed via direct one-photon ionization. We found that resonance-enhanced x-ray multiple ionization pathways play a dominant role in producing these nominally inaccessible charge states. Our calculated results agree with the measured Ar ion yield and pulse-duration dependence. We also predict the surprising ion yields reported earlier for Kr and Xe. The Monte Carlo rate equation method enables theoretical exploration of the complex dynamics of resonant high-intensity x-ray processes. PMID:25554879

Ho, Phay J; Bostedt, Christoph; Schorb, Sebastian; Young, Linda

2014-12-19

141

Theoretical Tracking of Resonance-Enhanced Multiple Ionization Pathways in X-ray Free-Electron Laser Pulses  

NASA Astrophysics Data System (ADS)

We present an extended Monte Carlo rate equation approach to examine the inner-shell ionization dynamics of atoms in an intense x-ray free-electron laser (XFEL) pulse. In addition to photoionization, Auger decay, and fluorescence processes, we include bound-to-bound transitions in the rate equation calculations. Using an efficient computational scheme, we account for "hidden resonances" unveiled during the course of an XFEL pulse. For Ar, the number of possible electron configurations is increased ten-billion-fold over that required under nonresonant conditions. We investigated the complex ionization dynamics of Ar atoms exposed to an 480-eV XFEL pulse, where production of ions above charge state 10 + is not allowed via direct one-photon ionization. We found that resonance-enhanced x-ray multiple ionization pathways play a dominant role in producing these nominally inaccessible charge states. Our calculated results agree with the measured Ar ion yield and pulse-duration dependence. We also predict the surprising ion yields reported earlier for Kr and Xe. The Monte Carlo rate equation method enables theoretical exploration of the complex dynamics of resonant high-intensity x-ray processes.

Ho, Phay J.; Bostedt, Christoph; Schorb, Sebastian; Young, Linda

2014-12-01

142

Cation binding to 15-TBA quadruplex DNA is a multiple-pathway cation-dependent process  

PubMed Central

A combination of explicit solvent molecular dynamics simulation (30 simulations reaching 4?µs in total), hybrid quantum mechanics/molecular mechanics approach and isothermal titration calorimetry was used to investigate the atomistic picture of ion binding to 15-mer thrombin-binding quadruplex DNA (G-DNA) aptamer. Binding of ions to G-DNA is complex multiple pathway process, which is strongly affected by the type of the cation. The individual ion-binding events are substantially modulated by the connecting loops of the aptamer, which play several roles. They stabilize the molecule during time periods when the bound ions are not present, they modulate the route of the ion into the stem and they also stabilize the internal ions by closing the gates through which the ions enter the quadruplex. Using our extensive simulations, we for the first time observed full spontaneous exchange of internal cation between quadruplex molecule and bulk solvent at atomistic resolution. The simulation suggests that expulsion of the internally bound ion is correlated with initial binding of the incoming ion. The incoming ion then readily replaces the bound ion while minimizing any destabilization of the solute molecule during the exchange. PMID:21893589

Reshetnikov, Roman V.; Sponer, Jiri; Rassokhina, Olga I.; Kopylov, Alexei M.; Tsvetkov, Philipp O.; Makarov, Alexander A.; Golovin, Andrey V.

2011-01-01

143

DEPTOR is linked to a TORC1-p21 survival proliferation pathway in multiple myeloma cells  

PubMed Central

We investigated the mechanism by which gene silencing of the mTOR inhibitor, DEPTOR, induces cytoreductive effects on multiple myeloma (MM) cells. DEPTOR knockdown resulted in anti-MM effects in several MM cell lines. Using an inducible shRNA to silence DEPTOR, 8226 MM cells underwent TORC1 activation, downregulation of AKT/SGK activity, apoptosis, cell cycle arrest and senescence. These latter cytotoxic effects were prevented by TORC1 paralysis (Raptor knockdown) but not by over-expression of AKT activity. In addition, DEPTOR knockdown-induced MM death was not associated with activation of the unfolded protein response, suggesting that enhanced ER stress did not play a role. In contrast, DEPTOR knockdown in 8226 cells induced p21 expression, independent of p53, and p21 knockdown prevented all of the cytotoxic effects following DEPTOR silencing. DEPTOR silencing resulted in p21 upregulation in additional MM cell lines. Furthermore, DEPTOR silencing in a murine xenograft model resulted in anti-MM effects associated with p21 upregulation. DEPTOR knockdown also resulted in a decreased expression of p21-targeting miRNAs and transfection of miRNA mimics prevented p21 upregulation and apoptosis following DEPTOR silencing. Use of a shRNA-resistant DEPTOR construct ruled out off-target effects of the shRNA. These results indicate that DEPTOR regulates growth and survival of MM cells via a TORC1/p21 pathway and suggest an involvement of p21-targeted miRNAs. PMID:25568666

Yang, Yonghui; Bardeleben, Carolyne; Frost, Patrick; Hoang, Bao; Shi, Yijiang; Finn, Richard; Gera, Joseph; Lichtenstein, Alan

2014-01-01

144

Multiple suppression pathways of canonical Wnt signalling control thymic epithelial senescence  

PubMed Central

Members of the Wnt family of secreted glyco-lipo-proteins affect intrathymic T-cell development and are abundantly secreted by thymic epithelial cells (TECs) that create the specific microenvironment for thymocytes to develop into mature T-cells. During ageing, Wnt expression declines allowing adipoid involution of the thymic epithelium leading to reduced naïve T-cell output. The protein kinase C (PKC) family of serine-threonine kinases is involved in numerous intracellular biochemical processes, including Wnt signal transduction. In the present study, PKC? expression is shown to increase with age and to co-localise with Wnt receptors Frizzled (Fz)-4 and -6. It is also demonstrated that connective tissue growth factor (CTGF) is a Wnt-4 target gene and is potentially involved in a negative feed-back loop of Wnt signal regulation. Down-regulation of Wnt-4 expression and activation of multiple repressor pathways suppressing ?-catenin dependent signalling in TECs contribute to the initiation of thymic senescence. PMID:21549744

Varecza, Zoltan; Kvell, Krisztian; Talabér, Gergely; Miskei, Gyorgy; Csongei, Veronika; Bartis, Domokos; Anderson, Graham; Jenkinson, Eric J.; Pongracz, Judit E.

2011-01-01

145

Galvanic zinc-copper microparticles inhibit melanogenesis via multiple pigmentary pathways.  

PubMed

The endogenous electrical field of human skin plays an important role in many skin functions. However, the biological effects and mechanism of action of externally applied electrical stimulation on skin remain unclear. Recent study showed that galvanic zinc-copper microparticles produce electrical stimulation and reduce inflammatory and immune responses in intact skin, suggesting the important role of electrical stimulation in non-wounded skin. The objective of this study is to investigate the biological effect of galvanic zinc-copper microparticles on skin pigmentation. Our findings showed that galvanic zinc-copper microparticles inhibited melanogenesis in a human melanoma cell line (MNT-1), human keratinocytes and melanoma cells co-cultures, and in pigmented epidermal equivalents. Treatment of galvanic zinc-copper microparticles inhibited melanogenesis by reducing the promoter transactivation of tyrosinase and tyrosinase-related protein-1 in human melanoma cells. In a co-culture Transwell system of keratinocytes and melanoma cells, galvanic zinc-copper microparticles reduced melanin production via downregulation of endothelin-1 secretion from keratinocytes and reduced tyrosinase gene expression in melanoma cells. In addition, exposure of pigmented epidermal equivalents to galvanic zinc-copper microparticles resulted in reduced melanin deposition. In conclusion, our data demonstrated for the first time that galvanic zinc-copper microparticles reduced melanogenesis in melanoma cells and melanin deposition in pigmented epidermal equivalents by affecting multiple pigmentary pathways. PMID:23700242

Won, Yen-Kim; Lin, Connie B; Seiberg, Miri; Chen, Nannan; Hu, Yaping; Rossetti, Dianne; Saliou, Claude; Loy, Chong-Jin

2014-01-01

146

A maternal effect rough deal mutation suggests that multiple pathways regulate Drosophila RZZ kinetochore recruitment.  

PubMed

Proper kinetochore recruitment and regulation of dynein and the Mad1-Mad2 complex requires the Rod-Zw10-Zwilch (RZZ) complex. Here, we describe rod(Z3), a maternal-effect Drosophila mutation changing a single residue in the Rough Deal (Rod) subunit of RZZ. Although the RZZ complex containing this altered subunit (denoted R(Z3)ZZ) is present in early syncytial stage embryos laid by homozygous rod(Z3) mothers, it is not recruited to kinetochores. Consequently, the embryos have no spindle assembly checkpoint (SAC), and syncytial mitoses are profoundly perturbed. The polar body (residual meiotic products) cannot remain in its SAC-dependent metaphase-like state, and decondenses into chromatin. In neuroblasts of homozygous rod(Z3) larvae, R(Z3)ZZ recruitment is only partially reduced, the SAC is functional and mitosis is relatively normal. R(Z3)ZZ nevertheless behaves abnormally: it does not further accumulate on kinetochores when microtubules are depolymerized; it reduces the rate of Mad1 recruitment; and it dominantly interferes with the dynein-mediated streaming of RZZ from attached kinetochores. These results suggest that the mutated residue of rod(Z3) is required for normal RZZ kinetochore recruitment and function and, moreover, that the RZZ recruitment pathway might differ in syncytial stage embryos and post-embryonic somatic cells. PMID:25616898

Défachelles, Lénaïg; Hainline, Sarah G; Menant, Alexandra; Lee, Laura A; Karess, Roger E

2015-03-15

147

Identification of Common Biological Pathways and Drug Targets Across Multiple Respiratory Viruses Based on Human Host Gene Expression Analysis  

PubMed Central

Background Pandemic and seasonal respiratory viruses are a major global health concern. Given the genetic diversity of respiratory viruses and the emergence of drug resistant strains, the targeted disruption of human host-virus interactions is a potential therapeutic strategy for treating multi-viral infections. The availability of large-scale genomic datasets focused on host-pathogen interactions can be used to discover novel drug targets as well as potential opportunities for drug repositioning. Methods/Results In this study, we performed a large-scale analysis of microarray datasets involving host response to infections by influenza A virus, respiratory syncytial virus, rhinovirus, SARS-coronavirus, metapneumonia virus, coxsackievirus and cytomegalovirus. Common genes and pathways were found through a rigorous, iterative analysis pipeline where relevant host mRNA expression datasets were identified, analyzed for quality and gene differential expression, then mapped to pathways for enrichment analysis. Possible repurposed drugs targets were found through database and literature searches. A total of 67 common biological pathways were identified among the seven different respiratory viruses analyzed, representing fifteen laboratories, nine different cell types, and seven different array platforms. A large overlap in the general immune response was observed among the top twenty of these 67 pathways, adding validation to our analysis strategy. Of the top five pathways, we found 53 differentially expressed genes affected by at least five of the seven viruses. We suggest five new therapeutic indications for existing small molecules or biological agents targeting proteins encoded by the genes F3, IL1B, TNF, CASP1 and MMP9. Pathway enrichment analysis also identified a potential novel host response, the Parkin-Ubiquitin Proteasomal System (Parkin-UPS) pathway, which is known to be involved in the progression of neurodegenerative Parkinson's disease. Conclusions Our study suggests that multiple and diverse respiratory viruses invoke several common host response pathways. Further analysis of these pathways suggests potential opportunities for therapeutic intervention. PMID:22432004

Smith, Steven B.; Dampier, William; Tozeren, Aydin; Brown, James R.; Magid-Slav, Michal

2012-01-01

148

The role of the PI3K-Akt signal transduction pathway in Autographa californica multiple nucleopolyhedrovirus infection of Spodoptera frugiperda cells  

SciTech Connect

Many viruses activate the phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathway, thereby modulating diverse downstream signaling pathways associated with antiapoptosis, proliferation, cell cycling, protein synthesis and glucose metabolism, in order to augment their replication. To date, the role of the PI3K-Akt pathway in Baculovirus replication has not been defined. In the present study, we demonstrate that infection of Sf9 cells with Autographa californica multiple nucleopolyhedrovirus (AcMNPV) elevated cellular Akt phosphorylation at 1 h post-infection. The maximum Akt phosphorylation occurred at 6 h post-infection and remained unchanged until 18 h post-infection. The PI3K-specific inhibitor, LY294002, suppressed Akt phosphorylation in a dose-dependent manner, suggesting that AcMNPV-induced Akt phosphorylation is PI3K-dependent. The inhibition of PI3K-Akt activation by LY294002 significantly reduced the viral yield, including a reduction in budded viruses and occlusion bodies. The virus production was reduced only when the inhibitor was added within 24 h of infection, implying that activation of PI3K occurred early in infection. Correspondingly, both viral DNA replication and late (VP39) and very late (POLH) viral protein expression were impaired by LY294002 treatment; LY294002 had no effect on immediate-early (IE1) and early-late (GP64) protein expression. These results demonstrate that the PI3K-Akt pathway is required for efficient Baculovirus replication.

Xiao Wei; Yang Yi; Weng Qingbei; Lin Tiehao; Yuan Meijin [State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou 510275 (China); Yang Kai, E-mail: yangkai@mail.sysu.edu.c [State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou 510275 (China); Pang Yi [State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou 510275 (China)

2009-08-15

149

Both PHYTOCHROME RAPIDLY REGULATED1 (PAR1) and PAR2 promote seedling photomorphogenesis in multiple light signaling pathways.  

PubMed

Arabidopsis (Arabidopsis thaliana) seedlings undergo photomorphogenesis in the light and etiolation in the dark. Light-activated photoreceptors transduce the light signals through a series of photomorphogenesis promoting or repressing factors to modulate many developmental processes in plants, such as photomorphogenesis and shade avoidance. CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) is a conserved RING finger E3 ubiquitin ligase, which mediates degradation of several photomorphogenesis promoting factors, including ELONGATED HYPOCOTYL5 (HY5) and LONG HYPOCOTYL IN FAR-RED1 (HFR1), through a 26S proteasome-dependent pathway. PHYTOCHROME RAPIDLY REGULATED1 (PAR1) was first detected as an early repressed gene in both phytochrome A (phyA)-mediated far-red and phyB-mediated red signaling pathways, and subsequent studies showed that both PAR1 and PAR2 are negative factors of shade avoidance in Arabidopsis. However, the role of PAR1 and PAR2 in seedling deetiolation, and their relationships with other photomorphogenesis promoting and repressing factors are largely unknown. Here, we confirmed that both PAR1 and PAR2 redundantly enhance seedling deetiolation in multiple photoreceptor signaling pathways. Their transcript abundances are repressed by phyA, phyB, and cryptochrome1 under far-red, red, and blue light conditions, respectively. Both PAR1 and PAR2 act downstream of COP1, and COP1 mediates the degradation of PAR1 and PAR2 through the 26S proteasome pathway. Both PAR1 and PAR2 act in a separate pathway from HY5 and HFR1 under different light conditions, except for sharing in the same pathway with HFR1 under far-red light. Together, our results substantiate that PAR1 and PAR2 are positive factors functioning in multiple photoreceptor signaling pathways during seedling deetiolation. PMID:24335334

Zhou, Peng; Song, Meifang; Yang, Qinghua; Su, Liang; Hou, Pei; Guo, Lin; Zheng, Xu; Xi, Yulin; Meng, Fanhua; Xiao, Yang; Yang, Li; Yang, Jianping

2014-02-01

150

The AMPK-PPARGC1A pathway is required for antimicrobial host defense through activation of autophagy.  

PubMed

AMP-activated protein kinase (AMPK) is a crucial energy sensor and plays a key role in integration of cellular functions to maintain homeostasis. Despite this, it is largely unknown whether targeting the AMPK pathway can be used as a therapeutic strategy for infectious diseases. Herein, we show that AMPK activation robustly induces antibacterial autophagy, which contributes to antimicrobial defense against Mycobacterium tuberculosis (Mtb). AMPK activation led to inhibition of Mtb-induced phosphorylation of the mechanistic target of rapamycin (MTOR) in macrophages. In addition, AMPK activation increased the genes involved in oxidative phosphorylation, mitochondrial ATP production, and biogenesis in Mtb-infected macrophages. Notably, peroxisome proliferator-activated receptor-gamma, coactivator 1? (PPARGC1A) was required for AMPK-mediated antimicrobial activity, as well as enhancement of mitochondrial function and biogenesis, in macrophages. Further, the AMPK-PPARGC1A pathway was involved in the upregulation of multiple autophagy-related genes via CCAAT/enhancer binding protein (C/EBP), ? (CEBPB). PPARGC1A knockdown inhibited the AMPK-mediated induction of autophagy and impaired the fusion of phagosomes with MAP1LC3B (LC3B) autophagosomes in Mtb-infected macrophages. The link between autophagy, mitochondrial function, and antimicrobial activity was further demonstrated by studying LysMCre-mediated knockout of atg7, demonstrating mitochondrial ultrastructural defects and dysfunction, as well as blockade of antimicrobial activity against mycobacteria. Collectively, our results identify the AMPK-PPARGC1A axis as contributing to autophagy activation leading to an antimicrobial response, as a novel host defense mechanism. PMID:24598403

Yang, Chul-Su; Kim, Jwa-Jin; Lee, Hye-Mi; Jin, Hyo Sun; Lee, Sang-Hee; Park, Ji-Hoon; Kim, Soung Jung; Kim, Jin-Man; Han, Yong-Mahn; Lee, Myung-Shik; Kweon, Gi Ryang; Shong, Minho; Jo, Eun-Kyeong

2014-05-01

151

Ancient and Novel Small RNA Pathways Compensate for the Loss of piRNAs in Multiple Independent Nematode Lineages  

PubMed Central

Small RNA pathways act at the front line of defence against transposable elements across the Eukaryota. In animals, Piwi interacting small RNAs (piRNAs) are a crucial arm of this defence. However, the evolutionary relationships among piRNAs and other small RNA pathways targeting transposable elements are poorly resolved. To address this question we sequenced small RNAs from multiple, diverse nematode species, producing the first phylum-wide analysis of how small RNA pathways evolve. Surprisingly, despite their prominence in Caenorhabditis elegans and closely related nematodes, piRNAs are absent in all other nematode lineages. We found that there are at least two evolutionarily distinct mechanisms that compensate for the absence of piRNAs, both involving RNA-dependent RNA polymerases (RdRPs). Whilst one pathway is unique to nematodes, the second involves Dicer-dependent RNA-directed DNA methylation, hitherto unknown in animals, and bears striking similarity to transposon-control mechanisms in fungi and plants. Our results highlight the rapid, context-dependent evolution of small RNA pathways and suggest piRNAs in animals may have replaced an ancient eukaryotic RNA-dependent RNA polymerase pathway to control transposable elements. PMID:25668728

Sarkies, Peter; Selkirk, Murray E.; Jones, John T.; Blok, Vivian; Boothby, Thomas; Goldstein, Bob; Hanelt, Ben; Ardila-Garcia, Alex; Fast, Naomi M.; Schiffer, Phillip M.; Kraus, Christopher; Taylor, Mark J.; Koutsovoulos, Georgios; Blaxter, Mark L.; Miska, Eric A.

2015-01-01

152

EFF-1-mediated regenerative axonal fusion requires components of the apoptotic pathway.  

PubMed

Functional regeneration after nervous system injury requires transected axons to reconnect with their original target tissue. Axonal fusion, a spontaneous regenerative mechanism identified in several species, provides an efficient means of achieving target reconnection as a regrowing axon is able to contact and fuse with its own separated axon fragment, thereby re-establishing the original axonal tract. Here we report a molecular characterization of this process in Caenorhabditis elegans, revealing dynamic changes in the subcellular localization of the EFF-1 fusogen after axotomy, and establishing phosphatidylserine (PS) and the PS receptor (PSR-1) as critical components for axonal fusion. PSR-1 functions cell-autonomously in the regrowing neuron and, instead of acting in its canonical signalling pathway, acts in a parallel phagocytic pathway that includes the transthyretin protein TTR-52, as well as CED-7, NRF-5 and CED-6 (refs 9, 10, 11, 12). We show that TTR-52 binds to PS exposed on the injured axon, and can restore fusion several hours after injury. We propose that PS functions as a 'save-me' signal for the distal fragment, allowing conserved apoptotic cell clearance molecules to function in re-establishing axonal integrity during regeneration of the nervous system. PMID:25567286

Neumann, Brent; Coakley, Sean; Giordano-Santini, Rosina; Linton, Casey; Lee, Eui Seung; Nakagawa, Akihisa; Xue, Ding; Hilliard, Massimo A

2015-01-01

153

Precise lamination of retinal axons generates multiple parallel input pathways in the tectum  

PubMed Central

The axons of retinal ganglion cells (RGCs) form topographic connections in the optic tectum, recreating a two-dimensional map of the visual field in the midbrain. RGC axons are also targeted to specific positions along the laminar axis of the tectum. Understanding the sensory transformations performed by the tectum requires identification of the rules that control the formation of synaptic laminae by RGC axons. However, there is little information regarding the spatial relationships between multiple axons as they establish laminar and retinotopic arborization fields within the same region of neuropil. Moreover, the contribution of RGC axon lamination to the processing of visual information is unknown. We have utilized Brainbow genetic labeling to visualize groups of individually identifiable axons during the assembly of a precise laminar map in the tectum. Live imaging of multiple RGCs revealed that axons target specific sublaminar positions during initial innervation and maintain their relative laminar positions throughout early larval development, ruling out a model for lamina selection based on iterative refinements. During this period of laminar stability, RGC arbors undergo structural rearrangements that shift their relative retinotopic positions. Analysis of cell type-specific lamination patterns revealed that distinct combinations of RGCs converge to form each sublamina, and this input heterogeneity correlates with different functional responses to visual stimuli. These findings suggest that lamina-specific sorting of retinal inputs provides an anatomical blueprint for the integration of visual features in the tectum. PMID:23486973

Robles, Estuardo; Filosa, Alessandro; Baier, Herwig

2013-01-01

154

Brief Communication Small GTPase Cdc42 Is Required for Multiple Aspects of  

E-print Network

Brief Communication Small GTPase Cdc42 Is Required for Multiple Aspects of Dendritic Morphogenesis aspects of dendritic morphogenesis. Cdc42-mutant VS neurons display normal complexity but increased that den- dritic morphogenesis requires an intrinsic differentiation pro- gram that is further instructed

Luo, Liqun

155

Morbillivirus v proteins exhibit multiple mechanisms to block type 1 and type 2 interferon signalling pathways.  

PubMed

Morbilliviruses form a closely related group of pathogenic viruses which encode three non-structural proteins V, W and C in their P gene. Previous studies with rinderpest virus (RPV) and measles virus (MeV) have demonstrated that these non-structural proteins play a crucial role in blocking type I (IFN?/?) and type II (IFN?) interferon action, and various mechanisms have been proposed for these effects. We have directly compared four important morbilliviruses, rinderpest (RPV), measles virus (MeV), peste des petits ruminants virus (PPRV) and canine distemper virus (CDV). These viruses and their V proteins could all block type I IFN action. However, the viruses and their V proteins had varying abilities to block type II IFN action. The ability to block type II IFN-induced gene transcription correlated with co-precipitation of STAT1 with the respective V protein, but there was no correlation between co-precipitation of either STAT1 or STAT2 and the abilities of the V proteins to block type I IFN-induced gene transcription or the creation of the antiviral state. Further study revealed that the V proteins of RPV, MeV, PPRV and CDV could all interfere with phosphorylation of the interferon-receptor-associated kinase Tyk2, and the V protein of highly virulent RPV could also block the phosphorylation of another such kinase, Jak1. Co-precipitation studies showed that morbillivirus V proteins all form a complex containing Tyk2 and Jak1. This study highlights the ability of morbillivirus V proteins to target multiple components of the IFN signalling pathways to control both type I and type II IFN action. PMID:23431397

Chinnakannan, Senthil K; Nanda, Sambit K; Baron, Michael D

2013-01-01

156

Biosynthesis of 2-Hydroxyethylphosphonate, an Unexpected Intermediate Common to Multiple Phosphonate Biosynthetic Pathways*S?  

PubMed Central

Phosphonic acids encompass a common yet chemically diverse class of natural products that often possess potent biological activities. Here we report that, despite the significant structural differences among many of these compounds, their biosynthetic routes contain an unexpected common intermediate, 2-hydroxyethyl-phosphonate, which is synthesized from phosphonoacetaldehyde by a distinct family of metal-dependent alcohol dehydrogenases (ADHs). Although the sequence identity of the ADH family members is relatively low (34–37%), in vitro biochemical characterization of the homologs involved in biosynthesis of the antibiotics fosfomycin, phosphinothricin tripeptide, and dehydrophos (formerly A53868) unequivocally confirms their enzymatic activities. These unique ADHs have exquisite substrate specificity, unusual metal requirements, and an unprecedented monomeric quaternary structure. Further, sequence analysis shows that these ADHs form a monophyletic group along with additional family members encoded by putative phosphonate biosynthetic gene clusters. Thus, the reduction of phosphonoacetaldehyde to hydroxyethyl-phosphonate may represent a common step in the biosynthesis of many phosphonate natural products, a finding that lends insight into the evolution of phosphonate biosynthetic pathways and the chemical structures of new C–P containing secondary metabolites. PMID:18544530

Shao, Zengyi; Blodgett, Joshua A. V.; Circello, Benjamin T.; Eliot, Andrew C.; Woodyer, Ryan; Li, Gongyong; van der Donk, Wilfred A.; Metcalf, William W.; Zhao, Huimin

2008-01-01

157

Biosynthesis of 2-hydroxyethylphosphonate, an unexpected intermediate common to multiple phosphonate biosynthetic pathways.  

PubMed

Phosphonic acids encompass a common yet chemically diverse class of natural products that often possess potent biological activities. Here we report that, despite the significant structural differences among many of these compounds, their biosynthetic routes contain an unexpected common intermediate, 2-hydroxyethyl-phosphonate, which is synthesized from phosphonoacetaldehyde by a distinct family of metal-dependent alcohol dehydrogenases (ADHs). Although the sequence identity of the ADH family members is relatively low (34-37%), in vitro biochemical characterization of the homologs involved in biosynthesis of the antibiotics fosfomycin, phosphinothricin tripeptide, and dehydrophos (formerly A53868) unequivocally confirms their enzymatic activities. These unique ADHs have exquisite substrate specificity, unusual metal requirements, and an unprecedented monomeric quaternary structure. Further, sequence analysis shows that these ADHs form a monophyletic group along with additional family members encoded by putative phosphonate biosynthetic gene clusters. Thus, the reduction of phosphonoacetaldehyde to hydroxyethyl-phosphonate may represent a common step in the biosynthesis of many phosphonate natural products, a finding that lends insight into the evolution of phosphonate biosynthetic pathways and the chemical structures of new C-P containing secondary metabolites. PMID:18544530

Shao, Zengyi; Blodgett, Joshua A V; Circello, Benjamin T; Eliot, Andrew C; Woodyer, Ryan; Li, Gongyong; van der Donk, Wilfred A; Metcalf, William W; Zhao, Huimin

2008-08-22

158

Multiple signaling pathways mediate compaction of collagen matrices by EGF-stimulated fibroblasts.  

PubMed

Fibroblasts stimulated by EGF within collagen matrices generate contraction forces that are likely of importance to cell migration and matrix compaction during wound healing. We have employed an in vitro fibroblast-embedded collagen matrix compaction assay to ascertain signaling pathway components downstream of EGFR activation leading to generation and transmission of contractile force. EGF compacts this floating collagen matrix to a similar extent as PDGF. We demonstrate that compaction requires EGFR kinase activity, yet is maximal in magnitude at intermediate EGF concentrations. This suggests that transmission of EGFR-induced contractile force to the matrix can be mitigated by consequent anti-adhesive effects of EGFR signaling in a dose-dependent manner. Treatment with pharmacological inhibitors demonstrated involvement of the signaling components extracellular signal-regulated kinase (ERK), Rho kinase, and myosin light chain kinase (MLCK) in the force generation and/or transmission process. Moreover, treatment with the pan-calpain inhibitor ALLN and isoform-specific downregulation of m-calpain (CAPN2) using RNA interference determined m-calpain to be a key component of the EGF-induced force response. ALLN treatment modulated the compaction response in a biphasic manner, enhancing matrix deformation to the greatest extent at intermediate concentrations. Our findings have thus identified key signals downstream of EGFR, which integrate in a complex manner to generate and transmit contractile forces to yield matrix deformation. PMID:16595133

Smith, Kirsty D; Wells, Alan; Lauffenburger, Douglas A

2006-07-01

159

Membrane localization of phosphatidylinositol 3-kinase is sufficient to activate multiple signal-transducing kinase pathways.  

PubMed Central

Phosphatidylinositol (PI) 3-kinase is a cytoplasmic signaling molecule recruited to the membrane by activated growth factor receptors. The p85 subunit of PI 3-kinase links the catalytic p110 subunit to activated growth factor receptors and is required for enzymatic activity of p110. In this report, we describe the effects of expressing novel forms of p110 that are targeted to the membrane by either N-terminal myristoylation or C-terminal farnesylation. The expression of membrane-localized p110 is sufficient to trigger downstream responses characteristic of growth factor action, including the stimulation of pp70 S6 kinase, Akt/Rac, and Jun N-terminal kinase (JNK). These responses can also be triggered by expression of a form of p110 (p110*) that is cytosolic but exhibits a high specific activity. Finally, targeting of pl10* to the membrane results in maximal activation of downstream responses. Our data demonstrate that either membrane-targeted forms of p110 or a form of p110 with high specific activity can act as constitutively active PI 3-kinases and induce PI 3-kinase-dependent responses in the absence of growth factor stimulation. The results also show that PI 3-kinase activation is sufficient to stimulate several kinases that appear to function in different signaling pathways. PMID:8754810

Klippel, A; Reinhard, C; Kavanaugh, W M; Apell, G; Escobedo, M A; Williams, L T

1996-01-01

160

Maintaining thermogenesis in cold exposed humans: relying on multiple metabolic pathways.  

PubMed

In cold exposed humans, increasing thermogenic rate is essential to prevent decreases in core temperature. This review describes the metabolic requirements of thermogenic pathways, mainly shivering thermogenesis, the largest contributor of heat. Research has shown that thermogenesis is sustained from a combination of carbohydrates, lipids, and proteins. The mixture of fuels is influenced by shivering intensity and pattern as well as by modifications in energy reserves and nutritional status. To date, there are no indications that differences in the types of fuel being used can alter shivering and overall heat production. We also bring forth the potential contribution of nonshivering thermogenesis in adult humans via the activation of brown adipose tissue (BAT) and explore some means to stimulate the activity of this highly thermogenic tissue. Clearly, the potential role of BAT, especially in young lean adults, can no longer be ignored. However, much work remains to clearly identify the quantitative nature of this tissue's contribution to total thermogenic rate and influence on shivering thermogenesis. Identifying ways to potentiate the effects of BAT via cold acclimation and/or the ingestion of compounds that stimulate the thermogenic process may have important implications in cold endurance and survival. PMID:25428848

Blondin, Denis P; Tingelstad, Hans Christian; Mantha, Olivier L; Gosselin, Chantal; Haman, François

2014-10-01

161

Outer Membrane Protein P5 Is Required for Resistance of Nontypeable Haemophilus influenzae to Both the Classical and Alternative Complement Pathways  

PubMed Central

The complement system is an important first line of defense against the human pathogen Haemophilus influenzae. To survive and propagate in vivo, H. influenzae has evolved mechanisms for subverting this host defense, most of which have been shown to involve outer surface structures, including lipooligosaccharide glycans and outer surface proteins. Bacterial defense against complement acts at multiple steps in the pathway by mechanisms that are not fully understood. Here we identify outer membrane protein P5 as an essential factor in serum resistance of both H. influenzae strain Rd and nontypeable H. influenzae (NTHi) clinical isolate NT127. P5 was essential for resistance of Rd and NT127 to complement in pooled human serum. Further investigation determined that P5 expression decreased cell surface binding of IgM, a potent activator of the classical pathway of complement, to both Rd and NT127. Additionally, P5 expression was required for NT127 to bind factor H (fH), an important inhibitor of alternative pathway (AP) activation. Collectively, the results obtained in this work highlight the ability of H. influenzae to utilize a single protein to perform multiple protective functions for evading host immunity. PMID:24478079

Rosadini, Charles V.; Ram, Sanjay

2014-01-01

162

Yvh1 is required for a late maturation step in the 60S biogenesis pathway  

PubMed Central

Before entering translation, preribosomal particles undergo sequential late maturation steps. In the case of pre-60S particles, these steps involve the release of shuttling maturation factors and transport receptors. In this study, we report a new maturation step in the 60S biogenesis pathway in budding yeast. We show that efficient release of the nucleolar/nuclear ribosomal-like protein Mrt4 (homologous to the acidic ribosomal P-protein Rpp0) from pre-60S particles requires the highly conserved protein Yvh1, which associates only with late pre-60S particles. Cell biological and biochemical analyses reveal that Mrt4 fails to dissociate from late pre-60S particles in yvh1? cells, inducing a delay in nuclear pre–ribosomal RNA processing and a pre-60S export defect in yvh1? cells. Moreover, we have isolated gain of function alleles of Mrt4 that specifically bypass the requirement for Yvh1 and rescue all yvh1?-associated phenotypes. Together, our data suggest that Yvh1-mediated release of Mrt4 precedes cytoplasmic loading of Rpp0 on pre-60S particles and is an obligatory late step toward construction of translation-competent 60S subunits. PMID:19797079

Kemmler, Stefan; Occhipinti, Laura; Veisu, Maria

2009-01-01

163

The Root Hair Assay Facilitates the Use of Genetic and Pharmacological Tools in Order to Dissect Multiple Signalling Pathways That Lead to Programmed Cell Death  

PubMed Central

The activation of programmed cell death (PCD) is often a result of complex signalling pathways whose relationship and intersection are not well understood. We recently described a PCD root hair assay and proposed that it could be used to rapidly screen genetic or pharmacological modulators of PCD. To further assess the applicability of the root hair assay for studying multiple signalling pathways leading to PCD activation we have investigated the crosstalk between salicylic acid, autophagy and apoptosis-like PCD (AL-PCD) in Arabidopsis thaliana. The root hair assay was used to determine rates of AL-PCD induced by a panel of cell death inducing treatments in wild type plants treated with chemical modulators of salicylic acid synthesis or autophagy, and in genetic lines defective in autophagy or salicylic acid signalling. The assay demonstrated that PCD induced by exogenous salicylic acid or fumonisin B1 displayed a requirement for salicylic acid signalling and was partially dependent on the salicylic acid signal transducer NPR1. Autophagy deficiency resulted in an increase in the rates of AL-PCD induced by salicylic acid and fumonisin B1, but not by gibberellic acid or abiotic stress. The phenylalanine ammonia lyase-dependent salicylic acid synthesis pathway contributed only to death induced by salicylic acid and fumonisin B1. 3-Methyladenine, which is commonly used as an inhibitor of autophagy, appeared to influence PCD induction in all treatments suggesting a possible secondary, non-autophagic, effect on a core component of the plant PCD pathway. The results suggest that salicylic acid signalling is negatively regulated by autophagy during salicylic acid and mycotoxin-induced AL-PCD. However, this crosstalk does not appear to be directly involved in PCD induced by gibberellic acid or abiotic stress. This study demonstrates that the root hair assay is an effective tool for relatively rapid investigation of complex signalling pathways leading to the activation of PCD. PMID:24755572

Kacprzyk, Joanna; Devine, Aoife; McCabe, Paul F.

2014-01-01

164

GATA4 knockdown in MA-10 Leydig cells identifies multiple target genes in the steroidogenic pathway.  

PubMed

GATA4 is an essential transcription factor required for the initiation of genital ridge formation, for normal testicular and ovarian differentiation at the time of sex determination, and for male and female fertility in adulthood. In spite of its crucial roles, the genes and/or gene networks that are ultimately regulated by GATA4 in gonadal tissues remain to be fully understood. This is particularly true for the steroidogenic lineages such as Leydig cells of the testis where many in vitro (promoter) studies have provided good circumstantial evidence that GATA4 is a key regulator of Leydig cell gene expression and steroidogenesis, but formal proof is still lacking. We therefore performed a microarray screening analysis of MA-10 Leydig cells in which Gata4 expression was knocked down using an siRNA strategy. Analysis identified several GATA4-regulated pathways including cholesterol synthesis, cholesterol transport, and especially steroidogenesis. A decrease in GATA4 protein was associated with decreased expression of steroidogenic genes previously suspected to be GATA4 targets such as Cyp11a1 and Star. Gata4 knockdown also led to an important decrease in other novel steroidogenic targets including Srd5a1, Gsta3, Hsd3b1, and Hsd3b6, as well as genes known to participate in cholesterol metabolism such as Scarb1, Ldlr, Soat1, Scap, and Cyp51. Consistent with the decreased expression of these genes, a reduction in GATA4 protein compromised the ability of MA-10 cells to produce steroids both basally and under hormone stimulation. These data therefore provide strong evidence that GATA4 is an essential transcription factor that sits atop of the Leydig cell steroidogenic program. PMID:25504870

Bergeron, Francis; Nadeau, Gabriel; S Viger, Robert

2015-03-01

165

mir-30d Regulates multiple genes in the autophagy pathway and impairs autophagy process in human cancer cells  

SciTech Connect

Highlights: ? Gene set enrichment analysis indicated mir-30d might regulate the autophagy pathway. ? mir-30d represses the expression of BECN1, BNIP3L, ATG12, ATG5 and ATG2. ? BECN1, BNIP3L, ATG12, ATG5 and ATG2 are direct targets of mir-30d. ? mir-30d inhibits autophagosome formation and LC3B-I conversion to LC3B-II. ? mir-30d regulates the autophagy process. -- Abstract: In human epithelial cancers, the microRNA (miRNA) mir-30d is amplified with high frequency and serves as a critical oncomir by regulating metastasis, apoptosis, proliferation, and differentiation. Autophagy, a degradation pathway for long-lived protein and organelles, regulates the survival and death of many cell types. Increasing evidence suggests that autophagy plays an important function in epithelial tumor initiation and progression. Using a combined bioinformatics approach, gene set enrichment analysis, and miRNA target prediction, we found that mir-30d might regulate multiple genes in the autophagy pathway including BECN1, BNIP3L, ATG12, ATG5, and ATG2. Our further functional experiments demonstrated that the expression of these core proteins in the autophagy pathway was directly suppressed by mir-30d in cancer cells. Finally, we showed that mir-30d regulated the autophagy process by inhibiting autophagosome formation and LC3B-I conversion to LC3B-II. Taken together, our results provide evidence that the oncomir mir-30d impairs the autophagy process by targeting multiple genes in the autophagy pathway. This result will contribute to understanding the molecular mechanism of mir-30d in tumorigenesis and developing novel cancer therapy strategy.

Yang, Xiaojun [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States) [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Department of General Surgery, Gansu Provincial Hospital, Lanzhou, Gansu 710000 (China); Zhong, Xiaomin [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States) [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011 (China); Tanyi, Janos L.; Shen, Jianfeng [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States)] [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Xu, Congjian [Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011 (China)] [Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011 (China); Gao, Peng [Department of General Surgery, Gansu Provincial Hospital, Lanzhou, Gansu 710000 (China)] [Department of General Surgery, Gansu Provincial Hospital, Lanzhou, Gansu 710000 (China); Zheng, Tim M. [Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104 (United States)] [Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104 (United States); DeMichele, Angela [Division of Hematology and Oncology, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104 (United States)] [Division of Hematology and Oncology, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104 (United States); Zhang, Lin, E-mail: linzhang@mail.med.upenn.edu [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States)] [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States)

2013-02-15

166

Selective inhibitor of endosomal trafficking pathways exploited by multiple toxins and viruses.  

PubMed

Pathogenic microorganisms and toxins have evolved a variety of mechanisms to gain access to the host-cell cytosol and thereby exert virulent effects upon the host. One common mechanism of cellular entry requires trafficking to an acidified endosome, which promotes translocation across the host membrane. To identify small-molecule inhibitors that block this process, a library of 30,000 small molecules was screened for inhibitors of anthrax lethal toxin. Here we report that 4-bromobenzaldehyde N-(2,6-dimethylphenyl)semicarbazone, the most active compound identified in the screen, inhibits intoxication by lethal toxin and blocks the entry of multiple other acid-dependent bacterial toxins and viruses into mammalian cells. This compound, which we named EGA, also delays lysosomal targeting and degradation of the EGF receptor, indicating that it targets host-membrane trafficking. In contrast, EGA does not block endosomal recycling of transferrin, retrograde trafficking of ricin, phagolysosomal trafficking, or phagosome permeabilization by Franciscella tularensis. Furthermore, EGA does not neutralize acidic organelles, demonstrating that its mechanism of action is distinct from pH-raising agents such as ammonium chloride and bafilomycin A1. EGA is a powerful tool for the study of membrane trafficking and represents a class of host-targeted compounds for therapeutic development to treat infectious disease. PMID:24191014

Gillespie, Eugene J; Ho, Chi-Lee C; Balaji, Kavitha; Clemens, Daniel L; Deng, Gang; Wang, Yao E; Elsaesser, Heidi J; Tamilselvam, Batcha; Gargi, Amandeep; Dixon, Shandee D; France, Bryan; Chamberlain, Brian T; Blanke, Steven R; Cheng, Genhong; de la Torre, Juan Carlos; Brooks, David G; Jung, Michael E; Colicelli, John; Damoiseaux, Robert; Bradley, Kenneth A

2013-12-10

167

Selective inhibitor of endosomal trafficking pathways exploited by multiple toxins and viruses  

PubMed Central

Pathogenic microorganisms and toxins have evolved a variety of mechanisms to gain access to the host-cell cytosol and thereby exert virulent effects upon the host. One common mechanism of cellular entry requires trafficking to an acidified endosome, which promotes translocation across the host membrane. To identify small-molecule inhibitors that block this process, a library of 30,000 small molecules was screened for inhibitors of anthrax lethal toxin. Here we report that 4-bromobenzaldehyde N-(2,6-dimethylphenyl)semicarbazone, the most active compound identified in the screen, inhibits intoxication by lethal toxin and blocks the entry of multiple other acid-dependent bacterial toxins and viruses into mammalian cells. This compound, which we named EGA, also delays lysosomal targeting and degradation of the EGF receptor, indicating that it targets host-membrane trafficking. In contrast, EGA does not block endosomal recycling of transferrin, retrograde trafficking of ricin, phagolysosomal trafficking, or phagosome permeabilization by Franciscella tularensis. Furthermore, EGA does not neutralize acidic organelles, demonstrating that its mechanism of action is distinct from pH-raising agents such as ammonium chloride and bafilomycin A1. EGA is a powerful tool for the study of membrane trafficking and represents a class of host-targeted compounds for therapeutic development to treat infectious disease. PMID:24191014

Gillespie, Eugene J.; Ho, Chi-Lee C.; Balaji, Kavitha; Clemens, Daniel L.; Deng, Gang; Wang, Yao E.; Elsaesser, Heidi J.; Tamilselvam, Batcha; Gargi, Amandeep; Dixon, Shandee D.; France, Bryan; Chamberlain, Brian T.; Blanke, Steven R.; Cheng, Genhong; de la Torre, Juan Carlos; Brooks, David G.; Jung, Michael E.; Colicelli, John; Damoiseaux, Robert; Bradley, Kenneth A.

2013-01-01

168

Multiple pathways for steel regulation suggested by genomic and sequence analysis of the murine Steel gene  

SciTech Connect

The Steel (Sl) locus encodes mast cell growth factor (Mgf) that is required for the development of germ cells, hematopoietic cells and melanocytes. Although the expression patterns of the Mgf gene are well characterized, little is known of the factors which regulate its expression. Here, we describe the cloning and sequence of the full-length transcription unit and the 5{prime} flanking region of the murine Mgf gene. The full-length Mgf mRNA consists of a short 5{prime} untranslated region (UTR), a 0.8-kb ORF and a long 3{prime} UTR. A single transcription initiation site is used in a number of mouse tissues and is located just downstream of binding sites for several known transcription factors. In the 5{prime} UTR, two ATGs were found upstream of the initiator methionine and are conserved among different species, suggesting that Mgf may be translationally regulated. At least two Mgf mRNAs are produced by alternative use of polyadenylation sites, but numerous other potential polyadenylation sites were found in the 3{prime} UTR. In addition, the 3{prime} UTR contains numerous sequence motifs that may regulate Mgf mRNA stability. These studies suggest multiple ways in which expression of Mgf may be regulated. 39 refs., 4 figs.

Bedell, M.A.; Copeland, N.G.; Jenkins, N.A. [NCI-Frederick Cancer Research and Development Center, Frederick, MD (United States)

1996-03-01

169

Determining the elastic properties of aptamer-ricin single molecule multiple pathway interactions  

NASA Astrophysics Data System (ADS)

We report on the elastic properties of ricin and anti-ricin aptamer interactions, which showed three stable binding conformations, each of which has its special elastic properties. These different unbinding pathways were investigated by the dynamic force spectroscopy. A series-spring model combining the worm-like-chain model and Hook's law was used to estimate the apparent spring constants of the aptamer and linker molecule polyethylene glycol. The aptamer in its three different unbinding pathways showed different apparent spring constants. The two reaction barriers in the unbinding pathways also influence the apparent spring constant of the aptamer. This special elastic behavior of aptamer was used to distinguish its three unbinding pathways under different loading rates. This method also offered a way to distinguish and discard the non-specific interactions in single molecule experiments.

Wang, Bin; Park, Bosoon; Kwon, Yongkuk; Xu, Bingqian

2014-05-01

170

Simultaneous Reconstruction of Multiple Signaling Pathways via the Prize-Collecting Steiner Forest Problem  

E-print Network

Signaling networks are essential for cells to control processes such as growth and response to stimuli. Although many “omic” data sources are available to probe signaling pathways, these data are typically sparse and noisy. ...

Tuncbag, Nurcan

171

Immunocell-array for Molecular Dissection of Multiple Signaling Pathways in Mammalian Cells  

Microsoft Academic Search

The knowledge of signaling pathways that are triggered by physiological and pathological conditions or drug treatment is essential for the comprehension of the bio- logical events that regulate cellular responses. Recently novel platforms based on \\

Andrea Zanardi; Luca Giorgetti; Oronza A. Botrugno; Saverio Minucci; Paolo Milani; Pier Giuseppe Pelicci; Roberta Carbone

2007-01-01

172

The Rab11 pathway is required for influenza A virus budding and filament formation.  

PubMed

Influenza A virus buds through the apical plasma membrane, forming enveloped virus particles that can take the shape of pleomorphic spheres or vastly elongated filaments. For either type of virion, the factors responsible for separation of viral and cell membranes are not known. We find that cellular Rab11 (a small GTP-binding protein involved in endocytic recycling) and Rab11-family interacting protein 3 ([FIP3] which plays a role in membrane trafficking and regulation of actin dynamics) are both required to support the formation of filamentous virions, while Rab11 is additionally involved in the final budding step of spherical particles. Cells transfected with Rab11 GTP-cycling mutants or depleted of Rab11 or FIP3 content by small interfering RNA treatment lost the ability to form virus filaments. Depletion of Rab11 resulted in up to a 100-fold decrease in titer of spherical virus released from cells. Scanning electron microscopy of Rab11-depleted cells showed high densities of virus particles apparently stalled in the process of budding. Transmission electron microscopy of thin sections confirmed that Rab11 depletion resulted in significant numbers of abnormally formed virus particles that had failed to pinch off from the plasma membrane. Based on these findings, we see a clear role for a Rab11-mediated pathway in influenza virus morphogenesis and budding. PMID:20357086

Bruce, Emily A; Digard, Paul; Stuart, Amanda D

2010-06-01

173

Adeno-associated virus 2 infection requires endocytosis through the CLIC/GEEC pathway.  

PubMed

Adeno-associated viruses (AAVs) are nonpathogenic, nonenveloped, single-stranded DNA viruses in development as gene therapy vectors. AAV internalization was postulated to proceed via a dynamin-dependent endocytic mechanism. Revisiting this, we find that infectious endocytosis of the prototypical AAV, AAV2, is independent of clathrin, caveolin, and dynamin. AAV2 infection is sensitive to EIPA, a fluid-phase uptake inhibitor, but is unaffected by Rac1 mutants or other macropinocytosis inhibitors. In contrast, AAV2 infection requires actin cytoskeleton remodeling and membrane cholesterol and is sensitive to inhibition of Cdc42, Arf1, and GRAF1, factors known to be involved in the formation of clathrin-independent carriers (CLIC). AAV2 virions are internalized in the detergent-resistant GPI-anchored-protein-enriched endosomal compartment (GEEC) and translocated to the Golgi apparatus, similarly to the CLIC/GEEC marker cholera toxin B. Our results indicate that-unlike the viral entry mechanisms described so far-AAV2 uses the pleiomorphic CLIC/GEEC pathway as its major endocytic infection route. PMID:22177561

Nonnenmacher, Mathieu; Weber, Thomas

2011-12-15

174

TNIK is required for postsynaptic and nuclear signalling pathways and cognitive function  

PubMed Central

Traf2 and NcK interacting Kinase (TNiK) contains serine-threonine kinase and scaffold domains and has been implicated in cell proliferation and glutamate receptor regulation in vitro. Here we report its role in vivo using mice carrying a knockout mutation. TNiK binds protein complexes in the synapse linking it to the NMDA receptor (NMDAR) via AKAP9. NMDAR and metabotropic receptors bidirectionally regulate TNiK phosphorylation and TNiK was required for AMPA expression and synaptic function. TNiK also organises nuclear complexes and in the absence of TNiK, there was a marked elevation in GSK3? and phosphorylation levels of its cognate phosphorylation sites on NeuroD1 with alterations in Wnt pathway signalling. We observed impairments in dentate gyrus neurogenesis in TNiK knockout mice and cognitive testing using the touchscreen apparatus revealed impairments in pattern separation on a test of spatial discrimination. Object-location paired associates learning, which is dependent on glutamatergic signalling was also impaired. Additionally, TNiK knockout mice displayed hyperlocomotor behavior that could be rapidly reversed by GSK3? inhibitors, indicating the potential for pharmacological rescue of a behavioral phenotype. These data establish TNiK as a critical regulator of cognitive functions and suggest it may play a regulatory role in diseases impacting on its interacting proteins and complexes. PMID:23035106

Coba, M.P.; Komiyama, N.H.; Nithianantharajah, J.; Kopanitsa, M.V.; Indersmitten, T.; Skene, N.G.; Tuck, E.J.; Fricker, D.G.; Elsegood, K.A.; Stanford, L.E.; Afinowi, N.; Saksida, L.M.; Bussey, T.J.; O’Dell, T.J.; Grant, S.G.N.

2014-01-01

175

General secretion pathway (eps) genes required for toxin secretion and outer membrane biogenesis in Vibrio cholerae.  

PubMed

The general secretion pathway (GSP) of Vibrio cholerae is required for secretion of proteins including chitinase, enterotoxin, and protease through the outer membrane. In this study, we report the cloning and sequencing of a DNA fragment from V. cholerae, containing 12 open reading frames, epsC to -N, which are similar to GSP genes of Aeromonas, Erwinia, Klebsiella, Pseudomonas, and Xanthomonas spp. In addition to the two previously described genes, epsE and epsM (M. Sandkvist, V. Morales, and M. Bagdasarian, Gene 123: 81-86, 1993; L. J. Overbye, M. Sandkvist, and M. Bagdasarian, Gene 132:101-106, 1993), it is shown here that epsC, epsF, epsG, and epsL also encode proteins essential for GSP function. Mutations in the eps genes result in aberrant outer membrane protein profiles, which indicates that the GSP, or at least some of its components, is required not only for secretion of soluble proteins but also for proper outer membrane assembly. Several of the Eps proteins have been identified by use of the T7 polymerase-promoter system in Escherichia coli. One of them, a pilin-like protein, EpsG, was analyzed also in V. cholerae and found to migrate as two bands on polyacrylamide gels, suggesting that in this organism it might be processed or otherwise modified by a prepilin peptidase. We believe that TcpJ prepilin peptidase, which processes the subunit of the toxin-coregulated pilus, TcpA, is not involved in this event. This is supported by the observations that apparent processing of EpsG occurs in a tcpJ mutant of V. cholerae and that, when coexpressed in E. coli, TcpJ cannot process EpsG although the PilD peptidase from Neisseria gonorrhoeae can. PMID:9371445

Sandkvist, M; Michel, L O; Hough, L P; Morales, V M; Bagdasarian, M; Koomey, M; DiRita, V J; Bagdasarian, M

1997-11-01

176

General secretion pathway (eps) genes required for toxin secretion and outer membrane biogenesis in Vibrio cholerae.  

PubMed Central

The general secretion pathway (GSP) of Vibrio cholerae is required for secretion of proteins including chitinase, enterotoxin, and protease through the outer membrane. In this study, we report the cloning and sequencing of a DNA fragment from V. cholerae, containing 12 open reading frames, epsC to -N, which are similar to GSP genes of Aeromonas, Erwinia, Klebsiella, Pseudomonas, and Xanthomonas spp. In addition to the two previously described genes, epsE and epsM (M. Sandkvist, V. Morales, and M. Bagdasarian, Gene 123: 81-86, 1993; L. J. Overbye, M. Sandkvist, and M. Bagdasarian, Gene 132:101-106, 1993), it is shown here that epsC, epsF, epsG, and epsL also encode proteins essential for GSP function. Mutations in the eps genes result in aberrant outer membrane protein profiles, which indicates that the GSP, or at least some of its components, is required not only for secretion of soluble proteins but also for proper outer membrane assembly. Several of the Eps proteins have been identified by use of the T7 polymerase-promoter system in Escherichia coli. One of them, a pilin-like protein, EpsG, was analyzed also in V. cholerae and found to migrate as two bands on polyacrylamide gels, suggesting that in this organism it might be processed or otherwise modified by a prepilin peptidase. We believe that TcpJ prepilin peptidase, which processes the subunit of the toxin-coregulated pilus, TcpA, is not involved in this event. This is supported by the observations that apparent processing of EpsG occurs in a tcpJ mutant of V. cholerae and that, when coexpressed in E. coli, TcpJ cannot process EpsG although the PilD peptidase from Neisseria gonorrhoeae can. PMID:9371445

Sandkvist, M; Michel, L O; Hough, L P; Morales, V M; Bagdasarian, M; Koomey, M; DiRita, V J; Bagdasarian, M

1997-01-01

177

Dissection of Biological Property of Chinese Acupuncture Point Zusanli Based on Long-Term Treatment via Modulating Multiple Metabolic Pathways.  

PubMed

Acupuncture has a history of over 3000 years and is a traditional Chinese medical therapy that uses hair-thin metal needles to puncture the skin at specific points on the body to promote wellbeing, while its molecular mechanism and ideal biological pathways are still not clear. High-throughput metabolomics is the global assessment of endogenous metabolites within a biologic system and can potentially provide a more accurate snap shot of the actual physiological state. We hypothesize that acupuncture-treated human would produce unique characterization of metabolic phenotypes. In this study, UPLC/ESI-HDMS coupled with pattern recognition methods and system analysis were carried out to investigate the mechanism and metabolite biomarkers for acupuncture treatment at "Zusanli" acupoint (ST-36) as a case study. The top 5 canonical pathways including alpha-linolenic acid metabolism, d-glutamine and d-glutamate metabolism, citrate cycle, alanine, aspartate, and glutamate metabolism, and vitamin B6 metabolism pathways were acutely perturbed, and 53 differential metabolites were identified by chemical profiling and may be useful to clarify the physiological basis and mechanism of ST-36. More importantly, network construction has led to the integration of metabolites associated with the multiple perturbation pathways. Urine metabolic profiling might be a promising method to investigate the molecular mechanism of acupuncture. PMID:24073005

Yan, Guangli; Zhang, Aihua; Sun, Hui; Cheng, Weiping; Meng, Xiangcai; Liu, Li; Zhang, Yingzhi; Xie, Ning; Wang, Xijun

2013-01-01

178

The Fanconi Anemia (FA\\/BRCA DNA damage repair pathway is reglated by NF[kappa]B and mediates drug resistance in multiple myeloma  

Microsoft Academic Search

The Fanconi Anemia (FA)\\/BRCA DNA damage repair pathway plays a critical role in the cellular response to stress induced by DNA alkylating agents and greatly influences drug response in cancer treatment. We recently reported that FA\\/BRCA DNA damage repair pathway genes are overexpressed and causative for resistance in multiple myeloma (MM) cell lines selected for resistance to melphalan. We hypothesized

Danielle N Yarde

2010-01-01

179

Arabidopsis Transcriptome Profiling Indicates That Multiple Regulatory Pathways Are Activated during Cold Acclimation in Addition to the CBF Cold Response PathwayW?  

PubMed Central

Many plants, including Arabidopsis, increase in freezing tolerance in response to low, nonfreezing temperatures, a phenomenon known as cold acclimation. Previous studies established that cold acclimation involves rapid expression of the CBF transcriptional activators (also known as DREB1 proteins) in response to low temperature followed by induction of the CBF regulon (CBF-targeted genes), which contributes to an increase in freezing tolerance. Here, we present the results of transcriptome-profiling experiments indicating the existence of multiple low-temperature regulatory pathways in addition to the CBF cold response pathway. The transcript levels of ?8000 genes were determined at multiple times after plants were transferred from warm to cold temperature and in warm-grown plants that constitutively expressed CBF1, CBF2, or CBF3. A total of 306 genes were identified as being cold responsive, with transcripts for 218 genes increasing and those for 88 genes decreasing threefold or more at one or more time points during the 7-day experiment. These results indicate that extensive downregulation of gene expression occurs during cold acclimation. Of the cold-responsive genes, 48 encode known or putative transcription factors. Two of these, RAP2.1 and RAP2.6, were activated by CBF expression and thus presumably control subregulons of the CBF regulon. Transcriptome comparisons indicated that only 12% of the cold-responsive genes are certain members of the CBF regulon. Moreover, at least 28% of the cold-responsive genes were not regulated by the CBF transcription factors, including 15 encoding known or putative transcription factors, indicating that these cold-responsive genes are members of different low-temperature regulons. Significantly, CBF expression at warm temperatures repressed the expression of eight genes that also were downregulated by low temperature, indicating that in addition to gene induction, gene repression is likely to play an integral role in cold acclimation. PMID:12172015

Fowler, Sarah; Thomashow, Michael F.

2002-01-01

180

Relaxin activates multiple cAMP signaling pathway profiles in different target cells.  

PubMed

Although RXFP1-cAMP signaling in HEK293T cell systems is now relatively well-defined, the signaling pathways activated by relaxin in its target cells and tissues are still unclear. This study aimed to examine the cAMP signaling of RXFP1 in cells that endogenously express the receptor. Seven cell types derived from various backgrounds were screened for receptor expression. Only in THP-1 cells and rat cardiac fibroblasts was there activation of the Galpha(i3)-Gbetagamma-phosphatidylinositol 3-kinase-protein kinase Czeta pathway, leading to cAMP accumulation. In all other cells there was activation of a combination of the initial pathways to affect cAMP. T-47D cells could activate only Galpha(s), whereas Colo 16 and rat renal fibroblasts from obstructed kidney could activate both Galpha(s) and Galpha(oB) pathways. Thus, the signaling pathways activated by relaxin are highly dependent upon the cell type under investigation, and this may help to explain the varied physiological responses exerted by relaxin in its different target tissues. PMID:19416169

Halls, Michelle L; Hewitson, Tim D; Moore, Xiao-Lei; Du, Xiao-Jun; Bathgate, Ross A D; Summers, Roger J

2009-04-01

181

Enzyme activity demonstrates multiple pathways of innate immunity in Indo-Pacific anthozoans  

PubMed Central

Coral reefs are threatened by increasing levels of coral disease and the functional loss of obligate algal symbionts (bleaching). Levels of immunity relate directly to susceptibility to these threats; however, our understanding of fundamental aspects of coral immunology is lacking. We show that three melanin-synthesis pathway components (mono-phenoloxidase, ortho-diphenoloxidase (tyrosinase-type pathway) and para-diphenoloxidase (laccase-type pathway)) are present in both their active (phenoloxidase, PO) and inactive (prophenoloxidase, PPO) forms across a diverse range of 22 species of healthy Indo-Pacific anthozoans. We also demonstrate transglutaminase activity of the coagulation cascade for, to our knowledge, the first time in a coral. Melanin-synthesis enzyme activities varied among taxa, although they were generally lowest in the coral family Acroporidae and highest in the Poritidae and Oculinidae. Inactive tyrosinase-type activity (PPO) and active laccase-type activity (PO) correlate with taxonomic patterns in disease resistance, whereas the converse pattern in activity levels correlates with bleaching resistance. Overall, we demonstrate the presence of several melanin-synthesis pathways in Indo-Pacific corals, co-regulation among some pathway components, and highlight their potential roles in coral health. PMID:22810430

Palmer, C. V.; Bythell, J. C.; Willis, B. L.

2012-01-01

182

The 3-hydroxy-2-butanone pathway is required for Pectobacterium carotovorum pathogenesis.  

PubMed

Pectobacterium species are necrotrophic bacterial pathogens that cause soft rot diseases in potatoes and several other crops worldwide. Gene expression data identified Pectobacterium carotovorum subsp. carotovorum budB, which encodes the ?-acetolactate synthase enzyme in the 2,3-butanediol pathway, as more highly expressed in potato tubers than potato stems. This pathway is of interest because volatiles produced by the 2,3-butanediol pathway have been shown to act as plant growth promoting molecules, insect attractants, and, in other bacterial species, affect virulence and fitness. Disruption of the 2,3-butanediol pathway reduced virulence of P. c. subsp. carotovorum WPP14 on potato tubers and impaired alkalinization of growth medium and potato tubers under anaerobic conditions. Alkalinization of the milieu via this pathway may aid in plant cell maceration since Pectobacterium pectate lyases are most active at alkaline pH. PMID:21876734

Marquez-Villavicencio, Maria del Pilar; Weber, Brooke; Witherell, R Andrews; Willis, David K; Charkowski, Amy O

2011-01-01

183

Single-target RNA interference for the blockade of multiple interacting proinflammatory and profibrotic pathways in cardiac fibroblasts.  

PubMed

Therapeutic targets of broad relevance are likely located in pathogenic pathways common to disorders of various etiologies. Screening for targets of this type revealed CCN genes to be consistently upregulated in multiple cardiomyopathies. We developed RNA interference (RNAi) to silence CCN2 and found this single-target approach to block multiple proinflammatory and profibrotic pathways in activated primary cardiac fibroblasts (PCFBs). The RNAi-strategy was developed in murine PCFBs and then investigated in "individual" human PCFBs grown from human endomyocardial biopsies (EMBs). Screening of short hairpin RNA (shRNA) sequences for high silencing efficacy and specificity yielded RNAi adenovectors silencing CCN2 in murine or human PCFBs, respectively. Comparison of RNAi with CCN2-modulating microRNA (miR) vectors expressing miR-30c or miR-133b showed higher efficacy of RNAi. In murine PCFBs, CCN2 silencing resulted in strongly reduced expression of stretch-induced chemokines (Ccl2, Ccl7, Ccl8), matrix metalloproteinases (MMP2, MMP9), extracellular matrix (Col3a1), and a cell-to-cell contact protein (Cx43), suggesting multiple signal pathways to be linked to CCN2. Immune cell chemotaxis towards CCN2-depleted PCFBs was significantly reduced. We demonstrate here that this RNAi strategy is technically applicable to "individual" human PCFBs, too, but that these display individually strikingly different responses to CCN2 depletion. Either genomically encoded factors or stable epigenetic modification may explain different responses between individual PCFBs. The new RNAi approach addresses a key regulator protein induced in cardiomyopathies. Investigation of this and other molecular therapies in individual human PCBFs may help to dissect differential pathogenic processes between otherwise similar disease entities and individuals. PMID:24239602

Tank, Juliane; Lindner, Diana; Wang, Xiaomin; Stroux, Andrea; Gilke, Leona; Gast, Martina; Zietsch, Christin; Skurk, Carsten; Scheibenbogen, Carmen; Klingel, Karin; Lassner, Dirk; Kühl, Uwe; Schultheiss, Heinz-Peter; Westermann, Dirk; Poller, Wolfgang

2014-01-01

184

Targeting Multiple Signaling Pathways by Green Tea Polyphenol ()-Epigallocatechin-3Gallate  

Microsoft Academic Search

Cell signaling pathways, responsible for maintaining a balance between cell proliferation and death, have emerged as rational targets for the management of cancer. Emerging data amassed from various laboratories around the world suggests that green tea, particularly its major polyphenolic constituent ()-epigallocatechin-3-gallate (EGCG), possesses remarkable cancer chemopreventive and therapeutic poten- tial against various cancer sites in animal tumor bioassay systems

Naghma Khan; Farrukh Afaq; Mohammad Saleem; Nihal Ahmad; Hasan Mukhtar

185

De novo assembly of a PML nuclear subcompartment occurs through multiple pathways and induces  

E-print Network

as functional intermediates of the ALT pathway. Key words: Alternative lengthening of telomeres, DNA repair, DNA into a specialized nucleoprotein complex. This structure protects the telomeres from being processed as a DNA double & BioQuant, Research Group Genome Organization & Function, Im Neuenheimer Feld 280, 69120 Heidelberg

Rippe, Karsten

186

Functional replacement of a primary metabolic pathway via multiple independent eukaryote-to-eukaryote gene transfers  

E-print Network

recognized as a major force in the evolution of prokaryotes (e.g. Boucher et al., 2003). However transferred between prokaryotes as well as from prokaryotes to eukaryotes [e.g. the transfer of a pathway involved in vitamin B6 biosynthesis, from a prokaryotic source to a nematode; (Craig et al., 2008

Nedelcu, Aurora M.

187

Multiple Developmental Pathways Leading to a Single Morph: Monosulcate Pollen (Examples From the Asparagales)  

PubMed Central

• Background and Aims Early developmental events in microsporogenesis are known to play a role in pollen morphology: variation in cytokinesis type, cell wall formation, tetrad shape and aperture polarity are responsible for pollen aperture patterning. Despite the existence of other morphologies, monosulcate pollen is one of the most common aperture types in monocots, and is also considered as the ancestral condition in this group. It is known to occur from either a successive or a simultaneous cytokinesis. In the present study, the developmental sequence of microsporogenesis is investigated in several species of Asparagales that produce such monosulcate pollen, representing most families of this important monocot clade. • Methods The developmental pathway of microsporogenesis was investigated using light transmission and epifluorescence microscopy for all species studied. Confocal microscopy was used to confirm centripetal cell plate formation. • Key Results Microsporogenesis is diverse in Asparagales, and most variation is generally found between families. It is confirmed that the whole higher Asparagales clade has a very conserved microsporogenesis, with a successive cytokinesis and centrifugal cell plate formation. Centripetal cell wall formation is described in Tecophilaeaceae and Iridaceae, a feature that had so far only been reported for eudicots. • Conclusions Monosulcate pollen can be obtained from several developmental pathways, leading thus to homoplasy in the monosulcate character state. Monosulcate pollen should not therefore be considered as the ancestral state unless it is produced through the ancestral developmental pathway. The question about the ancestral developmental pathway leading to monosulcy remains open. PMID:15567807

PENET, L.; NADOT, S.; RESSAYRE, A.; FORCHIONI, A.; DREYER, L.; GOUYON, P. H.

2004-01-01

188

Multiple phytohormone signalling pathways modulate susceptibility of tomato plants to Alternaria alternata f. sp. lycopersici  

PubMed Central

Three phytohormone molecules – ethylene (ET), jasmonic acid (JA) and salicylic acid (SA) – play key roles in mediating disease response to necrotrophic fungal pathogens. This study investigated the roles of the ET, JA, and SA pathways as well as their crosstalk during the interaction between tomato (Solanum lycopersicum) plants and a necrotrophic fungal pathogen Alternaria alternata f. sp. lycopersici (AAL). Both the ET and JASMONIC ACID INSENSITIVE1 (JAI1) receptor-dependent JA signalling pathways are necessary for susceptibility, while SA response promotes resistance to AAL infection. In addition, the role of JA in susceptibility to AAL is partly dependent on ET biosynthesis and perception, while the SA pathway enhances resistance to AAL and antagonizes the ET response. Based on these results, it is proposed that ET, JA, and SA each on their own can influence the susceptibility of tomato to AAL. Furthermore, the functions of JA and SA in susceptibility to the pathogen are correlated with the enhanced or decreased action of ET, respectively. This study has revealed the functional relationship among the three key hormone pathways in tomato defence against AAL. PMID:23264518

Jia, Chengguo; Zhang, Liping; Wang, Qiaomei

2013-01-01

189

NFAT5 regulates the canonical Wnt pathway and is required for cardiomyogenic differentiation  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer NFAT5 protein expression is downregulated during cardiomyogenesis. Black-Right-Pointing-Pointer Inhibition of NFAT5 function suppresses canonical Wnt signaling. Black-Right-Pointing-Pointer Inhibition of NFAT5 function attenuates mesodermal induction. Black-Right-Pointing-Pointer NFAT5 function is required for cardiomyogenesis. -- Abstract: While nuclear factor of activated T cells 5 (NFAT5), a transcription factor implicated in osmotic stress response, is suggested to be involved in other processes such as migration and proliferation, its role in cardiomyogenesis is largely unknown. Here, we examined the role of NFAT5 in cardiac differentiation of P19CL6 cells, and observed that it was abundantly expressed in undifferentiated P19CL6 cells, and its protein expression was significantly downregulated by enhanced proteasomal degradation during DMSO-induced cardiomyogenesis. Expression of a dominant negative mutant of NFAT5 markedly attenuated cardiomyogenesis, which was associated with the inhibition of mesodermal differentiation. TOPflash reporter assay revealed that the transcriptional activity of canonical Wnt signaling was activated prior to mesodermal differentiation, and this activation was markedly attenuated by NFAT5 inhibition. Pharmacological activation of canonical Wnt signaling by [2 Prime Z, 3 Prime E]-6-bromoindirubin-3 Prime -oxime (BIO) restored Brachyury expression in NFAT5DN-expressing cells. Inhibition of NFAT5 markedly attenuated Wnt3 and Wnt3a induction. Expression of Dkk1 and Cerberus1, which are secreted Wnt antagonists, was also inhibited by NFAT5 inhibition. Thus, endogenous NFAT5 regulates the coordinated expression of Wnt ligands and antagonists, which are essential for cardiomyogenesis through the canonical Wnt pathway. These results demonstrated a novel role of NFAT5 in cardiac differentiation of stem cells.

Adachi, Atsuo [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan)] [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan); Takahashi, Tomosaburo, E-mail: ttaka@koto.kpu-m.ac.jp [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan)] [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan); Ogata, Takehiro; Imoto-Tsubakimoto, Hiroko; Nakanishi, Naohiko [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan)] [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan); Ueyama, Tomomi, E-mail: toueyama-circ@umin.ac.jp [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan)] [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan); Matsubara, Hiroaki [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan)] [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan)

2012-09-28

190

Fungal Morphogenetic Pathways Are Required for the Hallmark Inflammatory Response during Candida albicans Vaginitis  

PubMed Central

Vulvovaginal candidiasis, caused primarily by Candida albicans, presents significant health issues for women of childbearing age. As a polymorphic fungus, the ability of C. albicans to switch between yeast and hyphal morphologies is considered its central virulence attribute. Armed with new criteria for defining vaginitis immunopathology, the purpose of this study was to determine whether the yeast-to-hypha transition is required for the hallmark inflammatory responses previously characterized during murine vaginitis. Kinetic analyses of vaginal infection with C. albicans in C57BL/6 mice demonstrated that fungal burdens remained constant throughout the observation period, while polymorphonuclear leukocyte (PMN), S100A8, and interleukin-1? levels obtained from vaginal lavage fluid increased by day 3 onward. Lactate dehydrogenase activity was also positively correlated with increased effectors of innate immunity. Additionally, immunodepletion of neutrophils in infected mice confirmed a nonprotective role for PMNs during vaginitis. Determination of the importance of fungal morphogenesis during vaginitis was addressed with a two-pronged approach. Intravaginal inoculation of mice with C. albicans strains deleted for key transcriptional regulators (bcr1?/?, efg1?/?, cph1?/?, and efg1?/? cph1?/?) controlling the yeast-to-hypha switch revealed a crucial role for morphogenetic signaling through the Efg1 and, to a lesser extent, the Bcr1 pathways in contributing to vaginitis immunopathology. Furthermore, overexpression of transcription factors NRG1 and UME6, to maintain yeast and hyphal morphologies, respectively, confirmed the importance of morphogenesis in generating innate immune responses in vivo. These results highlight the yeast-to-hypha switch and the associated morphogenetic response as important virulence components for the immunopathogenesis of Candida vaginitis, with implications for transition from benign colonization to symptomatic infection. PMID:24478069

Palmer, Glen E.; Nash, Andrea K.; Lilly, Elizabeth A.; Fidel, Paul L.; Noverr, Mairi C.

2014-01-01

191

Modulation of multiple pathways involved in the maintenance of neuronal function during aging by fisetin  

Microsoft Academic Search

Multiple factors have been implicated in the age-related declines in brain function. Thus, it is unlikely that modulating\\u000a only a single factor will be effective at slowing this decline. A better approach is to identify small molecules that have\\u000a multiple biological activities relevant to the maintenance of brain function. Over the last few years, we have identified\\u000a an orally active,

Pamela Maher

2009-01-01

192

Flow-Induced DNA Synthesis Requires Signaling to a Translational Control Pathway  

Microsoft Academic Search

Background. The mTOR translational control pathway that signals to the P70\\/P85 S6 kinase (pp70S6k) is essential for mitogenesis. We have previously shown that pp70S6k is activated by fluid flow. We hypothesized that oscillatory fluid flow in the absence of exogenous mitogens would induce endothelial cells to synthesize DNA via activation of the mTOR pathway. For comparison, we also studied the

Larry W. Kraiss; Tina M. Ennis; Neal M. Alto

2001-01-01

193

Functional replacement of a primary metabolic pathway via multiple independent eukaryote-to-eukaryote gene transfers and selective retention.  

PubMed

Although lateral gene transfer (LGT) is now recognized as a major force in the evolution of prokaryotes, the contribution of LGT to the evolution and diversification of eukaryotes is less understood. Notably, transfers of complete pathways are believed to be less likely between eukaryotes, because the successful transfer of a pathway requires the physical clustering of functionally related genes. Here, we report that in one of the closest unicellular relatives of animals, the choanoflagellate, Monosiga, three genes whose products work together in the glutamate synthase cycle are of algal origin. The concerted retention of these three independently acquired genes is best explained as the consequence of a series of adaptive replacement events. More generally, this study argues that (i) eukaryote-to-eukaryote transfers of entire metabolic pathways are possible, (ii) adaptive functional replacements of primary pathways can occur, and (iii) functional replacements involving eukaryotic genes are likely to have also contributed to the evolution of eukaryotes. Lastly, these data underscore the potential contribution of algal genes to the evolution of nonphotosynthetic lineages. PMID:19619164

Nedelcu, A M; Blakney, A J C; Logue, K D

2009-09-01

194

Differential gene expression in multiple neurological, inflammatory and connective tissue pathways in a spontaneous model of human small vessel stroke  

PubMed Central

Aims Cerebral small vessel disease (SVD) causes a fifth of all strokes plus diffuse brain damage leading to cognitive decline, physical disabilities and dementia. The aetiology and pathogenesis of SVD are unknown, but largely attributed to hypertension or microatheroma. Methods We used the spontaneously hypertensive stroke-prone rat (SHRSP), the closest spontaneous experimental model of human SVD, and age-matched control rats kept under identical, non-salt-loaded conditions, to perform a blinded analysis of mRNA microarray, qRT-PCR and pathway analysis in two brain regions (frontal and mid-coronal) commonly affected by SVD in the SHRSP at age five, 16 and 21 weeks. Results We found gene expression abnormalities, with fold changes ranging from 2.5 to 59 for the 10 most differentially expressed genes, related to endothelial tight junctions (reduced), nitric oxide bioavailability (reduced), myelination (impaired), glial and microglial activity (increased), matrix proteins (impaired), vascular reactivity (impaired) and albumin (reduced), consistent with protein expression defects in the same rats. All were present at age 5 weeks thus predating blood pressure elevation. ‘Neurological’ and ‘inflammatory’ pathways were more affected than ‘vascular’ functional pathways. Conclusions This set of defects, although individually modest, when acting in combination could explain the SHRSP's susceptibility to microvascular and brain injury, compared with control rats. Similar combined, individually modest, but multiple neurovascular unit defects, could explain susceptibility to spontaneous human SVD. PMID:24417612

Bailey, Emma L; McBride, Martin W; Beattie, Wendy; McClure, John D; Graham, Delyth; Dominiczak, Anna F; Sudlow, Cathie LM; Smith, Colin; Wardlaw, Joanna M

2014-01-01

195

Multiple signaling pathways regulate contractile activity?mediated PGC?1? gene expression and activity in skeletal muscle cells  

PubMed Central

Abstract PGC?1? is an important transcriptional coactivator that plays a key role in mediating mitochondrial biogenesis. Within seconds of the onset of contractile activity, a number of rapid cellular events occur that form part of the initial signaling processes involved in PGC?1? gene regulation, such as elevations in cytoplasmic calcium, AMPK and p38 activation, and elevated ROS production. We observed that basal levels of PGC?1? promoter activity were more sensitive to resting Ca2+ levels, compared to ROS, p38 or, AMPK signaling. Moreover, enhanced PGC?1? transcription and post?translational activity on DNA were a result of the activation of multiple signal transduction pathways during contractile activity of myotubes. AMPK, ROS, and Ca2+ appear to be necessary for the regulation of contractile activity?induced PGC?1? gene expression, governed partly through p38 MAPK and CaMKII activity. Whether these signaling pathways are arranged as a linear sequence of events, or as largely independent pathways during contractile activity, remains to be determined. PMID:24843073

Zhang, Yuan; Uguccioni, Giulia; Ljubicic, Vladimir; Irrcher, Isabella; Iqbal, Sobia; Singh, Kaustabh; Ding, Shuzhe; Hood, David A.

2014-01-01

196

Kainate excitotoxicity in organotypic hippocampal slice cultures: evidence for multiple apoptotic pathways  

Microsoft Academic Search

The mechanisms underlying kainate (KA) neurotoxicity are still not well understood. We previously reported that KA-mediated neuronal damage in organotypic cultures of hippocampal slices was associated with p53 induction. Recently, both bax and caspase-3 have been demonstrated to be key components of the p53-dependent neuronal death pathway. Caspase activation has also been causally related to the release of mitochondrial cytochrome

Wei Liu; Ruolan Liu; Jong Tai Chun; Ruifen Bi; Warren Hoe; Steven S Schreiber; Michel Baudry

2001-01-01

197

Noise-induced quantum coherence in photosynthetic complexes with multiple energy transfer pathways  

E-print Network

We theoretically investigate exciton relaxation dynamics in molecular aggregates based on model photosynthetic complexes under various conditions of incoherent excitation. We show that noise-induced quantum coherence is generated between spatially-separated exciton states which belong to the same or different energy transfer pathways, coupled via real and virtual transfer processes. Such quantum coherence effects may be used to improve light-harvesting efficiency and to reveal quantum phenomena in biology.

Dmitri V. Voronine; Konstantin E. Dorfman; Bin Cao; Amitabh Joshi

2014-08-12

198

Multiple pathways of inhibition shape bipolar cell responses in the retina  

PubMed Central

Bipolar cells (BCs) are critical relay neurons in the retina that are organized into parallel signaling pathways. The three main signaling pathways in the mammalian retina are the rod, ON cone, and OFF cone BCs. Rod BCs mediate incrementing dim light signals from rods, and ON cone and OFF cone BCs mediate incrementing and decrementing brighter light signals from cones, respectively. The outputs of BCs are shaped by inhibitory inputs from GABAergic and glycinergic amacrine cells in the inner plexiform layer, mediated by three distinct types of inhibitory receptors: GABAA, GABAC, and glycine receptors. The three main BC pathways receive distinct forms of inhibition from these three receptors that shape their light-evoked inhibitory signals. Rod BC inhibition is dominated by slow GABAC receptor inhibition, while OFF cone BCs are dominated by glycinergic inhibition. The inhibitory inputs to BCs are also shaped by serial inhibitory connections between GABAergic amacrine cells that limit the spatial profile of BC inhibition. We discuss our recent studies on how inhibitory inputs to BCs are shaped by receptor expression, receptor properties, and neurotransmitter release properties and how these affect the output of BCs. PMID:20932357

EGGERS, ERIKA D.; LUKASIEWICZ, PETER D.

2011-01-01

199

Evaluations of the trans-sulfuration pathway in multiple liver toxicity studies  

SciTech Connect

Drug-induced liver injury has been associated with the generation of reactive metabolites, which are primarily detoxified via glutathione conjugation. In this study, it was hypothesized that molecules involved in the synthesis of glutathione would be diminished to replenish the glutathione depleted through conjugation reactions. Since S-adenosylmethionine (SAMe) is the primary source of the sulfur atom in glutathione, UPLC/MS and NMR were used to evaluate metabolites involved with the transulfuration pathway in urine samples collected during studies of eight liver toxic compounds in Sprague-Dawley rats. Urinary levels of creatine were increased on day 1 or day 2 in 8 high dose liver toxicity studies. Taurine concentration in urine was increased in only 3 of 8 liver toxicity studies while SAMe was found to be reduced in 4 of 5 liver toxicity studies. To further validate the results from the metabonomic studies, microarray data from rat liver samples following treatment with acetaminophen was obtained from the Gene Expression Omnibus (GEO) database. Some genes involved in the trans-sulfuration pathway, including guanidinoacetate N-methyltransferase, glycine N-methyltransferase, betaine-homocysteine methyltransferase and cysteine dioxygenase were found to be significantly decreased while methionine adenosyl transferase II, alpha increased at 24 h post-dosing, which is consistent with the SAMe and creatine findings. The metabolic and transcriptomic results show that the trans-sulfuration pathway from SAMe to glutathione was disturbed due to the administration of heptatotoxicants.

Schnackenberg, Laura K. [Division of Systems Toxicology, National Center for Toxicological Research, Food and Drug Administration, FDA, Jefferson, AR 72079 (United States)], E-mail: richard.beger@fda.hhs.gov; Chen Minjun [Environmental Bioinformatics Computational Toxicology Center, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, NJ 08854 (United States); Sun, Jinchun; Holland, Ricky D.; Dragan, Yvonne; Tong Weida [Division of Systems Toxicology, National Center for Toxicological Research, Food and Drug Administration, FDA, Jefferson, AR 72079 (United States); Welsh, William [Environmental Bioinformatics Computational Toxicology Center, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, NJ 08854 (United States); Beger, Richard D. [Division of Systems Toxicology, National Center for Toxicological Research, Food and Drug Administration, FDA, Jefferson, AR 72079 (United States)

2009-02-15

200

Crosstalk between signaling pathways provided by single and multiple protein phosphorylation sites.  

PubMed

Cellular fate depends on the spatiotemporal separation and integration of signaling processes that can be provided by phosphorylation events. In this study, we identify the crucial points in signaling crosstalk that can be triggered by discrete phosphorylation events on a single target protein. We integrated the data on individual human phosphosites with the evidence on their corresponding kinases, the functional consequences of phosphorylation on activity of the target protein and corresponding pathways. Our results show that there is a substantial fraction of phosphosites that can play critical roles in crosstalk between alternative and redundant pathways and regulatory outcome of phosphorylation can be linked to a type of phosphorylated residue. These regulatory phosphosites can serve as hubs in the signal flow and their functional roles are directly connected to their specific properties. Namely, phosphosites with similar regulatory functions are phosphorylated by the same kinases and participate in regulation of similar biochemical pathways. Such sites are more likely to cluster in sequence and space unlike sites with antagonistic outcomes of their phosphorylation on a target protein. In addition, we found that in silico phosphorylation of sites with similar functional consequences has comparable outcomes on a target protein stability. An important role of phosphorylation sites in biological crosstalk is evident from the analysis of their evolutionary conservation. PMID:25451034

Nishi, Hafumi; Demir, Emek; Panchenko, Anna R

2015-01-30

201

Multiple Propionyl Coenzyme A-Supplying Pathways for Production of the Bioplastic Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) in Haloferax mediterranei  

PubMed Central

Haloferax mediterranei is able to accumulate the bioplastic poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with more than 10 mol% 3-hydroxyvalerate (3HV) from unrelated carbon sources. However, the pathways that produce propionyl coenzyme A (propionyl-CoA), an important precursor of 3HV monomer, have not yet been determined. Bioinformatic analysis of H. mediterranei genome indicated that this strain uses multiple pathways for propionyl-CoA biosynthesis, including the citramalate/2-oxobutyrate pathway, the aspartate/2-oxobutyrate pathway, the methylmalonyl-CoA pathway, and a novel 3-hydroxypropionate pathway. Cofeeding of pathway intermediates and inactivating pathway-specific genes supported that these four pathways were indeed involved in the biosynthesis of 3HV monomer. The novel 3-hydroxypropionate pathway that couples CO2 assimilation with PHBV biosynthesis was further confirmed by analysis of 13C positional enrichment in 3HV. Notably, 13C metabolic flux analysis showed that the citramalate/2-oxobutyrate pathway (53.0% flux) and the 3-hydroxypropionate pathway (30.6% flux) were the two main generators of propionyl-CoA from glucose. In addition, genetic perturbation on the transcriptome of the ?phaEC mutant (deficient in PHBV accumulation) revealed that a considerable number of genes in the four propionyl-CoA synthetic pathways were significantly downregulated. We determined for the first time four propionyl-CoA-supplying pathways for PHBV production in haloarchaea, particularly including a new 3-hydroxypropionate pathway. These results would provide novel strategies for the production of PHBV with controllable 3HV molar fraction. PMID:23435886

Han, Jing; Hou, Jing; Zhang, Fan; Ai, Guomin; Li, Ming; Cai, Shuangfeng; Liu, Hailong; Wang, Lei; Wang, Zejian; Zhang, Siliang; Cai, Lei; Zhao, Dahe; Zhou, Jian

2013-01-01

202

A MAP Kinase pathway in Caenorhabditis elegans is required for defense against infection by opportunistic Proteus species.  

PubMed

Caenorhabditis elegans innate immunity requires a conserved mitogen activated protein kinase (MAPK) pathway that regulates the basal and pathogen-induced expression of immune effectors. Being in the group of opportunistic pathogens, Proteus spp. cause large number of nosocomial infections. Since, Proteus spp. do not cause death in wild type C. elegans, to understand the role and contribution of MAP Kinase pathway, the mutants (sek-1 and pmk-1) of this pathway were employed. Physiological experiments revealed that the Proteus spp. were able to kill MAP Kinase pathway mutant's C. elegans significantly. To understand the involvement of innate immune pathways specific players at the mRNA level, the regulation of few candidate antimicrobial genes were kinetically investigated during Proteus spp. infections. Real-time PCR analysis indicated a regulation of few candidate immune regulatory genes (F08G5.6, lys-7, nlp-29, ATF-7 and daf-16) during the course of Proteus spp. infections. In addition, the lipopolysaccharides (LPS) isolated from Proteus mirabilis upon exposure to mutant C. elegans showed modifications at their functional regions suggesting that the pathogen modifies its internal machinery according to the specific host for effective pathogenesis. PMID:23597661

JebaMercy, Gnanasekaran; Vigneshwari, Loganathan; Balamurugan, Krishnaswamy

2013-01-01

203

Signaling pathway requirements for induction of senescence by telomere homolog oligonucleotides.  

PubMed

Cellular senescence is a major defense against cancer. In human fibroblasts, suppressing both the p53 and pRb pathways is necessary to bypass replicative senescence as well as senescence induced by ectopic expression of a dominant negative form of the telomere repeat binding factor 2, TRF2(DN). We recently reported that exposure to oligonucleotides homologous to the telomere 3' overhang (T-oligos) activates both the p53 and pRb pathways and leads to senescence in primary human fibroblasts. To further characterize T-oligo-induced senescence, we compared established isogenic fibroblast cell lines lacking functional p53 and/or pRb pathways to the normal parental line. Here, we report that, as in physiologic senescence, inactivation of both the p53 and pRb pathways is necessary to suppress T-oligo-induced senescence. Moreover, T-oligo rapidly induces senescence in a malignant fibroblast-derived cell line, demonstrating the potential of using T-oligo as a novel anticancer therapeutic. Our data support the hypothesis that exposure of the TTAGGG tandem repeat telomere 3' overhang sequence is the event that initiates signaling through DNA damage response pathways after experimental telomere disruption, serial passage, or acute genomic damage of normal cells. PMID:15530855

Li, Guang-Zhi; Eller, Mark S; Hanna, Kendra; Gilchrest, Barbara A

2004-12-10

204

Neuroprotective effects and intracellular signaling pathways of erythropoietin in a rat model of multiple sclerosis  

Microsoft Academic Search

In multiple sclerosis (MS), long-term disability is primarily caused by axonal and neuronal damage. We demonstrated in a previous study that neuronal apoptosis occurs early during experimental autoimmune encephalomyelitis, a common animal model of MS. In the present study, we show that, in rats suffering from myelin oligodendrocyte glycoprotein (MOG)-induced optic neuritis, systemic application of erythropoietin (Epo) significantly increased survival

D Merkler; K Maier; C Stadelmann; H Ehrenreich; M Bähr; R Diem; M Sättler

2004-01-01

205

The C5 Convertase Is Not Required for Activation of the Terminal Complement Pathway in Murine Experimental Cerebral Malaria*  

PubMed Central

Cerebral malaria (CM) is the most severe manifestation of clinical malaria syndromes and has a high fatality rate especially in the developing world. Recent studies demonstrated that C5?/? mice are resistant to experimental CM (ECM) and that protection was due to the inability to form the membrane attack complex. Unexpectedly, we observed that C4?/? and factor B?/? mice were fully susceptible to disease, indicating that activation of the classical or alternative pathways is not required for ECM. C3?/? mice were also susceptible to ECM, indicating that the canonical C5 convertases are not required for ECM development and progression. Abrogation of ECM by treatment with anti-C9 antibody and detection of C5a in serum of C3?/? mice confirmed that C5 activation occurs in ECM independent of C5 convertases. Our data indicate that activation of C5 in ECM likely occurs via coagulation enzymes of the extrinsic protease pathway. PMID:22689574

Ramos, Theresa N.; Darley, Meghan M.; Weckbach, Sebastian; Stahel, Philip F.; Tomlinson, Stephen; Barnum, Scott R.

2012-01-01

206

Methoxychlor affects multiple hormone signaling pathways in the largemouth bass (Micropterus salmoides) liver  

PubMed Central

Methoxychlor (MXC) is an organochlorine pesticide that has been shown to have estrogenic activity by activating estrogen receptors and inducing vitellogenin production in male fish. Previous studies report that exposure to MXC induces changes in mRNA abundance of reproductive genes in the liver and testes of largemouth bass (Micropterus salmoides). The objective of the present study was to better characterize the mode of action of MXC by measuring the global transcriptomic response in the male largemouth liver using an oligonucleotide microarray. Microarray analysis identified highly significant changes in the expression of 37 transcripts (p<0.001) (20 induced and 17 decreased) in the liver after MXC injection and a total of 900 expression changes (p<0.05) in transcripts with high homology to known genes. Largemouth bass estrogen receptor alpha (esr1) and androgen receptor (ar) were among the transcripts that were increased in the liver after MXC treatment. Functional enrichment analysis identified the molecular functions of steroid binding and androgen receptor activity as well as steroid hormone receptor activity as being significantly over-represented gene ontology terms. Pathway analysis identified c-fos signaling as being putatively affected through both estrogen and androgen signaling. This study provides evidence that MXC elicits transcriptional effects through the estrogen receptor as well as androgen receptor-mediated pathways in the liver. PMID:21276474

Martyniuk, Christopher J.; Spade, Daniel J.; Blum, Jason L.; Kroll, Kevin J.; Denslow, Nancy D.

2011-01-01

207

Rational engineering of multiple module pathways for the production of L-phenylalanine in Corynebacterium glutamicum.  

PubMed

Microbial production of L-phenylalanine (L-Phe) from renewable sources has attracted much attention recently. In the present study, Corynebacterium glutamicum 13032 was rationally engineered to produce L-Phe from inexpensive glucose. First, all the L-Phe biosynthesis pathway genes were investigated and the results demonstrated that in addition to AroF and PheA, the native PpsA, TktA, AroE and AroA, and the heterologous AroL and TyrB were also the key enzymes for L-Phe biosynthesis. Through combinational expression of these key enzymes, the L-Phe production was increased to 6.33 ± 0.13 g l(-1) which was about 1.48-fold of that of the parent strain C. glutamicum (pXM-pheA (fbr)-aroF (fbr)) (fbr, feedback-inhibition resistance). Furthermore, the production of L-Phe was improved to 9.14 ± 0.21 g l(-1) by modifying the glucose and L-Phe transport systems and blocking the acetate and lactate biosynthesis pathways. Eventually, the titer of L-Phe was enhanced to 15.76 ± 0.23 g l(-1) with a fed-batch fermentation strategy. To the best of our knowledge, this was the highest value reported in rationally engineered C. glutamicum 13032 strains. The results obtained will also contribute to rational engineering of C. glutamicum for production of other valuable aromatic compounds. PMID:25665502

Zhang, Chuanzhi; Zhang, Junli; Kang, Zhen; Du, Guocheng; Chen, Jian

2015-05-01

208

Multiple pathways regulating the anti-apoptotic protein clusterin in breast cancer  

PubMed Central

Cancer chemotherapy inhibits tumor growth, in part, by triggering apoptosis, and anti-apoptotic proteins reduce the effectiveness of chemotherapy. Clusterin, a chaperone-like protein that binds to apoptotic and DNA repair proteins, is induced by chemotherapy and promotes tumor cell survival. Histone deacetylase inhibitors (HDIs) such as sodium butyrate and suberoylanilide hydroxamic acid (SAHA) are pharmacological agents that induce differentiation and apoptosis in cancer cells by altering chromatin structure, and we have found that combinations of chemotherapeutic drugs such as doxorubicin and HDIs efficiently induce apoptosis, even though they paradoxically induce high levels of clusterin. The hyper-expressed form of clusterin localizes to mitochondria, inhibits cytochrome c release, and is inhibited by the proteasome. When HDIs are used as single agents, clusterin suppresses cytochrome c release and apoptosis. However, doxorubicin/HDI-induced apoptosis is not inhibited by clusterin, and clusterin-resistant apoptosis corresponds with markers of the extrinsic/receptor-mediated apoptotic pathway. Thus, chemotherapy-HDI combinations are capable of overcoming an innate anti-apoptotic pathway of tumor cells, suggesting that chemotherapy-HDI combinations have potential for treating advanced stage breast cancer. PMID:17689225

Ranney, Melissa K.; Ahmed, Ikhlas S.A.; Potts, Kelly R.; Craven, Rolf J.

2012-01-01

209

The proinflammatory cytokine interleukin-18 alters multiple signaling pathways to inhibit natural killer cell death  

USGS Publications Warehouse

The proinflammatory cytokine, interleukin-18 (IL-18), is a natural killer (NK) cell activator that induces NK cell cytotoxicity and interferon-?? (IFN-??) expression. In this report, we define a novel role for IL-18 as an NK cell protective agent. Specifically, IL-18 prevents NK cell death initiated by different and distinct stress mechanisms. IL-18 reduces NK cell self-destruction during NK-targeted cell killing, and in the presence of staurosporin, a potent apoptotic inducer, IL-18 reduces caspase-3 activity. The critical regulatory step in this process is downstream of the mitochondrion and involves reduced cleavage and activation of caspase-9 and caspase-3. The ability of IL-18 to regulate cell survival is not limited to a caspase death pathway in that IL-18 augments tumor necrosis factor (TNF) signaling, resulting in increased and prolonged mRNA expression of c-apoptosis inhibitor 2 (cIAP2), a prosurvival factor and caspase-3 inhibitor, and TNF receptor-associated factor 1 (TRAF1), a prosurvival protein. The cumulative effects of IL-18 define a novel role for this cytokine as a molecular survival switch that functions to both decrease cell death through inhibition of the mitochondrial apoptotic pathway and enhance TNF induction of prosurvival factors. ?? Mary Ann Liebert, Inc.

Hodge, D.L.; Subleski, J.J.; Reynolds, D.A.; Buschman, M.D.; Schill, W.B.; Burkett, M.W.; Malyguine, A.M.; Young, H.A.

2006-01-01

210

Multiple Independent Fusions of Glucose-6-Phosphate Dehydrogenase with Enzymes in the Pentose Phosphate Pathway  

PubMed Central

Fusions of the first two enzymes in the pentose phosphate pathway, glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconolactonase (6PGL), have been previously described in two distant clades, chordates and species of the malarial parasite Plasmodium. We have analyzed genome and expressed sequence data from a variety of organisms to identify the origins of these gene fusion events. Based on the orientation of the domains and range of species in which homologs can be found, the fusions appear to have occurred independently, near the base of the metazoan and apicomplexan lineages. Only one of the two metazoan paralogs of G6PD is fused, showing that the fusion occurred after a duplication event, which we have traced back to an ancestor of choanoflagellates and metazoans. The Plasmodium genes are known to contain a functionally important insertion that is not seen in the other apicomplexan fusions, highlighting this as a unique characteristic of this group. Surprisingly, our search revealed two additional fusion events, one that combined 6PGL and G6PD in an ancestor of the protozoan parasites Trichomonas and Giardia, and another fusing G6PD with phosphogluconate dehydrogenase (6PGD) in a species of diatoms. This study extends the range of species known to contain fusions in the pentose phosphate pathway to many new medically and economically important organisms. PMID:21829610

Stover, Nicholas A.; Dixon, Thomas A.; Cavalcanti, Andre R. O.

2011-01-01

211

Modulation of Cell Metabolic Pathways and Oxidative Stress Signaling Contribute to Acquired Melphalan Resistance in Multiple Myeloma Cells  

PubMed Central

Alkylating agents are widely used chemotherapeutics in the treatment of many cancers, including leukemia, lymphoma, multiple myeloma, sarcoma, lung, breast and ovarian cancer. Melphalan is the most commonly used chemotherapeutic agent against multiple myeloma. However, despite a 70–80% initial response rate, virtually all patients eventually relapse due to the emergence of drug-resistant tumour cells. By using global proteomic and transcriptomic profiling on melphalan sensitive and resistant RPMI8226 cell lines followed by functional assays, we discovered changes in cellular processes and pathways not previously associated with melphalan resistance in multiple myeloma cells, including a metabolic switch conforming to the Warburg effect (aerobic glycolysis), and an elevated oxidative stress response mediated by VEGF/IL8-signaling. In addition, up-regulated aldo-keto reductase levels of the AKR1C family involved in prostaglandin synthesis contribute to the resistant phenotype. Finally, selected metabolic and oxidative stress response enzymes were targeted by inhibitors, several of which displayed a selective cytotoxicity against the melphalan-resistant cells and should be further explored to elucidate their potential to overcome melphalan resistance. PMID:25769101

Zub, Kamila Anna; de Sousa, Mirta Mittelstedt Leal; Sarno, Antonio; Sharma, Animesh; Demirovic, Aida; Rao, Shalini; Young, Clifford; Aas, Per Arne; Ericsson, Ida; Sundan, Anders; Jensen, Ole Nørregaard; Slupphaug, Geir

2015-01-01

212

Epithelial barrier assembly requires coordinated activity of multiple domains of the tight junction protein ZO-1  

PubMed Central

Summary Tight junctions (TJs) regulate the paracellular movement of ions, macromolecules and immune cells across epithelia. Zonula occludens (ZO)-1 is a multi-domain polypeptide required for the assembly of TJs. MDCK II cells lacking ZO-1, and its homolog ZO-2, have three distinct phenotypes: reduced localization of occludin and some claudins to the TJs, increased epithelial permeability, and expansion of the apical actomyosin contractile array found at the apical junction complex (AJC). However, it is unclear exactly which ZO-1 binding domains are required to coordinate these activities. We addressed this question by examining the ability of ZO-1 domain-deletion transgenes to reverse the effects of ZO depletion. We found that the SH3 domain and the U5 motif are required to recruit ZO-1 to the AJC and that localization is a prerequisite for normal TJ and cytoskeletal organization. The PDZ2 domain is not required for localization of ZO-1 to the AJC, but is necessary to establish the characteristic continuous circumferential band of ZO-1, occludin and claudin-2. PDZ2 is also required to establish normal permeability, but is not required for normal cytoskeletal organization. Finally, our results demonstrate that PDZ1 is crucial for the normal organization of both the TJ and the AJC cytoskeleton. Our results establish that ZO-1 acts as a true scaffolding protein and that the coordinated activity of multiple domains is required for normal TJ structure and function. PMID:23418357

Rodgers, Laurel S.; Beam, M. Tanner; Anderson, James M.; Fanning, Alan S.

2013-01-01

213

Dhx34 and Nbas function in the NMD pathway and are required for embryonic development in zebrafish  

PubMed Central

The nonsense-mediated mRNA decay (NMD) pathway is a highly conserved surveillance mechanism that is present in all eukaryotes. It prevents the synthesis of truncated proteins by selectively degrading mRNAs harbouring premature termination codons (PTCs). The core NMD effectors were originally identified in genetic screens in Saccharomyces cerevisae and in the nematode Caenorhabditis elegans, and subsequently by homology searches in other metazoans. A genome-wide RNAi screen in C. elegans resulted in the identification of two novel NMD genes that are essential for proper embryonic development. Their human orthologues, DHX34 and NAG/NBAS, are required for NMD in human cells. Here, we find that the zebrafish genome encodes orthologues of DHX34 and NAG/NBAS. We show that the morpholino-induced depletion of zebrafish Dhx34 and Nbas proteins results in severe developmental defects and reduced embryonic viability. We also found that Dhx34 and Nbas are required for degradation of PTC-containing mRNAs in zebrafish embryos. The phenotypes observed in both Dhx34 and Nbas morphants are similar to defects in Upf1, Smg-5- or Smg-6- depleted embryos, suggesting that these factors affect the same pathway and confirming that zebrafish embryogenesis requires an active NMD pathway. PMID:21227923

Anastasaki, Corina; Longman, Dasa; Capper, Amy; Patton, E. Elizabeth

2011-01-01

214

Multiplication  

NSDL National Science Digital Library

How sharp are your multiplication skills? Give these great math games a try ! Play Asteroids blaster and test your multiplication skills. How fast can you solve the problem... play a round of Baseball multiplication and see! Multiplication is fun and delicious with Crazy Cones. Help Lemonade Larry determine the correct amount! Test your multiplication skills with Tic Tac Toe! ...

Ms.Roberts

2009-02-24

215

A Subset of Signal Transduction Pathways Is Required for Hippocampal Growth Cone Collapse Induced by Ephrin-A5  

PubMed Central

The Eph family tyrosine kinase receptors and their ligands, ephrins, play key roles in a wide variety of physiological and pathological processes including tissue patterning, angiogenesis, bone development, carcinogenesis, axon guidance, and neural plasticity. However, the signaling mechanisms underlying these diverse functions of Eph receptors have not been well understood. In this study, effects of Eph receptor activation on several important signal transduction pathways are examined. In addition, the roles of these pathways in ephrin-A5-induced growth cone collapse were assessed with a combination of biochemical analyses, pharmacological inhibition, and overexpression of dominant-negative and constitutively active mutants. These analyses showed that ephrin-A5 inhibits Erk activity while activates c-Jun N-terminal kinase. However, regulation of these two pathways is not required for ephrin-A5-induced growth cone collapse in hippocampal neurons. Artificial Erk activation by expression of constitutively active Mek1 and B-Raf failed to block ephrin-A5 effects on growth cones, and inhibitors of the Erk pathway also failed to inhibit collapse by ephrin-A5. Inhibition of JNK had no effects on ephrin-A5-induced growth cone collapse either. In addition, inhibitors to PKA and PI3-K showed no effects on ephrin-A5-induced growth cone collapse. However, pharmacological blockade of phosphotyrosine phosphatase activity, the Src family kinases, cGMP-dependent protein kinase, and myosin light chain kinase significantly inhibited ephrin-A5-induced growth cone collapse. These observations indicate that only a subset of signal transduction pathways is required for ephrin-A5-induced growth cone collapse. PMID:18563700

Yue, Xin; Dreyfus, Cheryl; Kong, Tony Ah-Ng; Zhou, Renping

2009-01-01

216

Luteolin, a bioflavonoid inhibits colorectal cancer through modulation of multiple signaling pathways: a review.  

PubMed

Luteolin, 3', 4', 5,7-tetrahydroxyflavone, belongs to a group of naturally occurring compounds called flavonoids that are found widely in the plant kingdom. It possesses many beneficial properties including antioxidant, anti- inflammatory, anti-bacterial, anti-diabetic and anti-proliferative actions. Colorectal cancer (CRC) is a leading cause of cancer related deaths worldwide. Many signaling pathways are deregulated during the progression of colon cancer. In this review we aimed to analyze the protection offered by luteolin on colon cancer. During colon cancer genesis, luteolin known to reduce oxidative stress thereby protects the cell to undergo damage in vivo. Wnt/?-catenin signaling, deregulated during neoplastic development, is modified by luteolin. Hence, luteolin can be considered as a potential drug to treat CRC. PMID:25081655

Pandurangan, Ashok Kumar; Esa, Norhaizan Mohd

2014-01-01

217

Life Stress, Genes, and Depression: Multiple Pathways Lead to Increased Risk and New Opportunities for Intervention  

NSDL National Science Digital Library

This STKE Review with 2 figures and 122 references concerns the interaction between stress, genetic factors, and vulnerability to depression. Evidence suggests that the combination of genetics, early life stress, and ongoing stress determine how an individual responds to stress and his vulnerability to psychiatric disorders, such as depression. It is likely that genetic factors and life stress contribute not only to alterations in various neurotransmitter systems, but also to the impairments of cellular plasticity and resilience that are observed in depression. Increased understanding of the specific cellular and neurochemical alterations that contribute to depression, and of the intracellular signaling pathways that underlie cellular plasticity and resilience, may lead to the identification of novel therapeutic targets and, therefore, to the development of novel antidepressant therapies.

Dennis S. Charney (National Institute of Mental Health; Mood and Anxiety Disorders Research Program REV)

2004-03-23

218

Multiple Pathways of Duplication Formation with and Without Recombination (RecA) in Salmonella enterica  

PubMed Central

Duplications are often attributed to “unequal recombination” between separated, directly repeated sequence elements (>100 bp), events that leave a recombinant element at the duplication junction. However, in the bacterial chromosome, duplications form at high rates (10?3–10?5/cell/division) even without recombination (RecA). Here we describe 1800 spontaneous lac duplications trapped nonselectively on the low-copy F?128 plasmid, where lac is flanked by direct repeats of the transposable element IS3 (1258 bp) and by numerous quasipalindromic REP elements (30 bp). Duplications form at a high rate (10?4/cell/division) that is reduced only about 11-fold in the absence of RecA. With and without RecA, most duplications arise by recombination between IS3 elements (97%). Formation of these duplications is stimulated by IS3 transposase (Tnp) and plasmid transfer functions (TraI). Three duplication pathways are proposed. First, plasmid dimers form at a high rate stimulated by RecA and are then modified by deletions between IS3 elements (resolution) that leave a monomeric plasmid with an IS3-flanked lac duplication. Second, without RecA, duplications occur by single-strand annealing of DNA ends generated in different sister chromosomes after transposase nicks DNA near participating IS3 elements. The absence of RecA may stimulate annealing by allowing chromosome breaks to persist. Third, a minority of lac duplications (3%) have short (0–36 bp) junction sequences (SJ), some of which are located within REP elements. These duplication types form without RecA, Tnp, or Tra by a pathway in which the palindromic junctions of a tandem inversion duplication (TID) may stimulate deletions that leave the final duplication. PMID:22865732

Reams, Andrew B.; Kofoid, Eric; Kugelberg, Elisabeth; Roth, John R.

2012-01-01

219

Zfrp8/PDCD2 is required in ovarian stem cells and interacts with the piRNA pathway machinery  

PubMed Central

The maintenance of stem cells is central to generating diverse cell populations in many tissues throughout the life of an animal. Elucidating the mechanisms involved in how stem cells are formed and maintained is crucial to understanding both normal developmental processes and the growth of many cancers. Previously, we showed that Zfrp8/PDCD2 is essential for the maintenance of Drosophila hematopoietic stem cells. Here, we show that Zfrp8/PDCD2 is also required in both germline and follicle stem cells in the Drosophila ovary. Expression of human PDCD2 fully rescues the Zfrp8 phenotype, underlining the functional conservation of Zfrp8/PDCD2. The piRNA pathway is essential in early oogenesis, and we find that nuclear localization of Zfrp8 in germline stem cells and their offspring is regulated by some piRNA pathway genes. We also show that Zfrp8 forms a complex with the piRNA pathway protein Maelstrom and controls the accumulation of Maelstrom in the nuage. Furthermore, Zfrp8 regulates the activity of specific transposable elements also controlled by Maelstrom and Piwi. Our results suggest that Zfrp8/PDCD2 is not an integral member of the piRNA pathway, but has an overlapping function, possibly competing with Maelstrom and Piwi. PMID:24381196

Minakhina, Svetlana; Changela, Neha; Steward, Ruth

2014-01-01

220

Microcanonical molecular simulations of methane hydrate nucleation and growth: evidence that direct nucleation to sI hydrate is among the multiple nucleation pathways.  

PubMed

The results of six high-precision constant energy molecular dynamics (MD) simulations initiated from methane-water systems equilibrated at 80 MPa and 250 K indicate that methane hydrates can nucleate via multiple pathways. Five trajectories nucleate to an amorphous solid. One trajectory nucleates to a structure-I hydrate template with long-range order which spans the simulation box across periodic boundaries despite the presence of several defects. While experimental and simulation data for hydrate nucleation with different time- and length-scales suggest that there may exist multiple pathways for nucleation, including metastable intermediates and the direct formation of the globally-stable phase, this work provides the most compelling evidence that direct formation to the globally stable crystalline phase is one of the multiple pathways available for hydrate nucleation. PMID:25743115

Zhang, Zhengcai; Walsh, Matthew R; Guo, Guang-Jun

2015-04-14

221

Multiple in vivo pathways for E. coli small ribosomal subunit assembly occur on one pre-rRNA  

PubMed Central

Processing of transcribed precursor ribosomal RNA (pre-rRNA) to a mature state is a conserved aspect of ribosome biogenesis in vivo. We developed an affinity purification system to isolate and analyze in vivo formed pre-rRNA containing ribonucleoprotein particles (rRNPs) from wild-type E. coli. We observed that the first processing intermediate of pre-SSU rRNA is a platform for biogenesis. These pre-SSU containing RNPs have differing ribosomal protein and auxiliary factors association and rRNA folding. Each RNP lacks the proper architecture in functional regions suggesting that checkpoints preclude immature subunits from entering the translational cycle. This work offers in vivo snapshots of SSU biogenesis and reveals that multiple pathways exist for the entire SSU biogenesis process in wild-type E. coli. These findings have important implications in understanding SSU biogenesis in vivo and offer a general strategy for analysis of RNP biogenesis. PMID:25195050

Gupta, Neha

2015-01-01

222

MicroRNA-145: a potent tumour suppressor that regulates multiple cellular pathways  

PubMed Central

MicroRNAs are endogenous, small (18–25 nucleotides) non-coding RNAs, which regulate genes expression by directly binding to the 3?-untranslated regions of the target messenger RNAs. Emerging evidence shows that alteration of microRNAs is involved in cancer development. MicroRNA-145 is commonly down-regulated in many types of cancer, regulating various cellular processes, such as the cell cycle, proliferation, apoptosis and invasion, by targeting multiple oncogenes. This review aims to summarize the recent published literature on the role of microRNA-145 in regulating tumourigenesis and progression, and explore its potential for cancer diagnosis, prognosis and treatment. PMID:25124875

Cui, Shi-Yun; Wang, Rui; Chen, Long-Bang

2014-01-01

223

Cybernetic modeling and regulation of metabolic pathways in multiple steady states of hybridoma cells.  

PubMed

Hybridoma cells utilize a pair of complementary and partially substitutable substrates, glucose and glutamine, for growth. It has been shown that cellular metabolism shifts under different culture conditions. When those cultures at different metabolic states are switched to a continuous mode, they reach different steady states under the same operating conditions. A cybernetic model was constructed to describe the complementary and partial substitutable nature of substrate utilization. The model successfully predicted the metabolic shift and multiple steady-state behavior. The results are consistent with the experimental observation that the history of the culture affects the resulting steady state. PMID:11027180

Guardia, M J; Gambhir, A; Europa, A F; Ramkrishna, D; Hu, W S

2000-01-01

224

Overcoming inherent resistance to histone deacetylase inhibitors in multiple myeloma cells by targeting pathways integral to the actin cytoskeleton  

PubMed Central

Histone deacetylase inhibitors (HDACi) are novel chemotherapeutics undergoing evaluation in clinical trials for the potential treatment of patients with multiple myeloma (MM). Although HDACi have demonstrable synergy when combined with proteasome inhibitors (PIs), recent evidence indicates that combination of HDACi and PI is beneficial only in a subset of patients with advanced MM, clearly indicating that other rational combinations should be explored. In this context we hypothesized that understanding the molecular signature associated with inherent resistance to HDACi would provide a basis for the identification of therapeutic combinations with improved clinical efficacy. Using human myeloma cell lines (HMCL) categorized as sensitive, intermediate or resistant to HDACi, gene expression profiling (GEP) and gene ontology enrichment analyses were performed to determine if a genetic signature associated with inherent resistance to HDACi-resistance could be identified. Correlation of GEP to increasing or decreasing sensitivity to HDACi indicated a unique 35-gene signature that was significantly enriched for two pathways – regulation of actin cytoskeleton and protein processing in endoplasmic reticulum. When HMCL and primary MM samples were treated with a combination of HDACi and agents targeting the signaling pathways integral to the actin cytoskeleton, synergistic cell death was observed in all instances, thus providing a rationale for combining these agents with HDACi for the treatment of MM to overcome resistance. This report validates a molecular approach for the identification of HDACi partner drugs and provides an experimental framework for the identification of novel therapeutic combinations for anti-MM treatment. PMID:24651437

Mithraprabhu, S; Khong, T; Spencer, A

2014-01-01

225

Network-based multiple sclerosis pathway analysis with GWAS data from 15,000 cases and 30,000 controls.  

PubMed

Multiple sclerosis (MS) is an inflammatory CNS disease with a substantial genetic component, originally mapped to only the human leukocyte antigen (HLA) region. In the last 5 years, a total of seven genome-wide association studies and one meta-analysis successfully identified 57 non-HLA susceptibility loci. Here, we merged nominal statistical evidence of association and physical evidence of interaction to conduct a protein-interaction-network-based pathway analysis (PINBPA) on two large genetic MS studies comprising a total of 15,317 cases and 29,529 controls. The distribution of nominally significant loci at the gene level matched the patterns of extended linkage disequilibrium in regions of interest. We found that products of genome-wide significantly associated genes are more likely to interact physically and belong to the same or related pathways. We next searched for subnetworks (modules) of genes (and their encoded proteins) enriched with nominally associated loci within each study and identified those modules in common between the two studies. We demonstrate that these modules are more likely to contain genes with bona fide susceptibility variants and, in addition, identify several high-confidence candidates (including BCL10, CD48, REL, TRAF3, and TEC). PINBPA is a powerful approach to gaining further insights into the biology of associated genes and to prioritizing candidates for subsequent genetic studies of complex traits. PMID:23731539

2013-06-01

226

DLC1 tumor suppressor gene inhibits migration and invasion of multiple myeloma cells through RhoA GTPase pathway  

PubMed Central

DLC1, a tumor suppressor gene that encodes a RhoGTPase-activating protein, is recurrently downregulated or silenced in various solid tumors and hematological malignancies due to epigenetic modifications or genomic deletion. Here, we identified DLC-1 promoter hypermethylation in 43 out of 44 multiple myeloma (MM) cell lines, which resulted in downregulation or silencing of DLC1 in 41 samples. High frequency of tumor-specific methylation and attenuation or silencing of DLC1 expression could serve as an independent diagnostic marker for MM. Combined treatment with demethylating and acetylating agents significantly elevated the expression of DLC1 and suppressed MM cell proliferation. Two cell lines exhibiting complete promoter methylation and absence of DLC1 expression were transduced by an adenoviral vector containing DLC1 cDNA. In both cell lines reexpression of DLC1 inhibited myeloma cell invasion and migration, reduced RhoA activity and resulted in reorganization of actin cytoskeleton. These results provide the first evidence for antiproliferative effect of DLC1 in a hematological cancer and implicate RhoA pathway in suppression of MM migration and invasion. Given the myeloma cells sensitivity to reactivation of DLC-1 function, the potential for molecular targeted therapy of DLC-1 mediated pathways as well as epigenetic therapies hold prospects. PMID:18923442

Ullmannova-Benson, Veronika; Guan, Ming; Zhou, Xiaoling; Tripathi, Veenu; Yang, Xu-Yu; Zimonjic, Drazen B.; Popescu, Nicholas C

2009-01-01

227

Probing the structural requirements for vitamin D3 inhibition of the hedgehog signaling pathway.  

PubMed

A structure-activity relationship study to elucidate the structural basis for hedgehog (Hh) signaling inhibition by vitamin D3 (VD3) was performed. Functional and non-functional regions of VD3 and VD2 were obtained through straightforward synthetic means and their biological activity was determined in a variety of cell-based assays. Several of these compounds inhibited Hh signaling at levels comparable to the parent VD3 with no effects on canonical vitamin D signaling. Most notably, compounds 5 and 9, demonstrated potent inhibition of the Hh pathway, exhibited no binding affinity for the vitamin D receptor (VDR), and did not activate VDR in cell culture. In addition, several compounds exhibited anti-proliferative activity against two human cancer cell lines through a mechanism distinct from the Hh or VDR pathways, suggesting a new cellular mechanism of action for this class of compounds. PMID:22687748

DeBerardinis, Albert M; Banerjee, Upasana; Miller, Michele; Lemieux, Steven; Hadden, M Kyle

2012-07-15

228

Multiple Smaller Missions as a Direct Pathway to Mars Sample Return  

NASA Technical Reports Server (NTRS)

Recent discoveries by the Mars Exploration Rovers, Mars Express, Mars Odyssey, and Mars Reconnaissance Orbiter spacecraft include multiple, tantalizing astrobiological targets representing both past and present environments on Mars. The most desirable path to Mars Sample Return (MSR) would be to collect and return samples from that site which provides the clearest examples of the variety of rock types considered a high priority for sample return (pristine igneous, sedimentary, and hydrothermal). Here we propose an MSR architecture in which the next steps (potentially launched in 2018) would entail a series of smaller missions, including caching, to multiple landing sites to verify the presence of high priority sample return targets through in situ analyses. This alternative architecture to one flagship-class sample caching mission to a single site would preserve a direct path to MSR as stipulated by the Planetary Decadal Survey, while permitting investigation of diverse deposit types and providing comparison of the site of returned samples to other aqueous environments on early Mars

Niles, P. B.; Draper, D. S.; Evans, C. A.; Gibson, E. K.; Graham, L. D.; Jones, J. H.; Lederer, S. M.; Ming, D.; Seaman, C. H.; Archer, P. D.; Andrews-Hanna, J.; Baldridge, A. M.; Bourke, M. C.; Crown, D. A.; Fries, M.; Knudson, A. T.; Michalski, J.; Dobrea, E. Noe; Vaniman, D.; Weitz, C. M.; Williams, R. M. E.; Bell, J. F., III; Knauth, L. P.

2012-01-01

229

Multiple pathways are involved in DNA degradation during keratinocyte terminal differentiation  

PubMed Central

Loss of the nucleus is a critical step in keratinocyte terminal differentiation. To elucidate the mechanisms involved, we focused on two characteristic events: nuclear translocation of N-terminal fragment of profilaggrin and caspase-14-dependent degradation of the inhibitor of caspase-activated DNase (ICAD). First, we demonstrated that epidermal mesotrypsin liberated a 55-kDa N-terminal fragment of profilaggrin (FLG-N) and FLG-N was translocated into the nucleus. Interestingly, these cells became TUNEL positive. Mutation in the mesotrypsin-susceptible Arg-rich region between FLG-N and the first filaggrin domain abolished these changes. Furthermore, caspase-14 caused limited proteolysis of ICAD, followed by accumulation of caspase-activated DNase (CAD) in TUNEL-positive nuclei. Knockdown of both proteases resulted in a significant increase of remnant nuclei in a skin equivalent model. Immunohistochemical study revealed that both caspase-14 and mesotrypsin were markedly downregulated in parakeratotic areas of lesional skin from patients with atopic dermatitis and psoriasis. Collectively, our results indicate that at least two pathways are involved in the DNA degradation process during keratinocyte terminal differentiation. PMID:24743736

Yamamoto-Tanaka, M; Makino, T; Motoyama, A; Miyai, M; Tsuboi, R; Hibino, T

2014-01-01

230

Multiple pathways of DNA double-strand break processing in a mutant Indian muntjac cell line  

SciTech Connect

DNA break processing is compared in the Indian muntjac cell lines, SVM and DM. The initial frequencies and resealing of X-ray generated single- and double-strand breaks are similar in the two cell lines. Inhibiting the repair of UV damage leads to greater double-strand breakage in SVM than in DM, and some of these breaks are not repaired; however, repair-associated single-strand breakage and resealing are normal. Dimethylsulfate also induces excess double-strand breakage in SVM, and these breaks are irreparable. Restricted plasmids are reconstituted correctly in SVM at approximately 30% of the frequency observed in DM. Thus SVM has a reduced capacity to repair certain types of double-strand break. This defect is not due to a DNA ligase deficiency. We conclude that DNA double-strand breaks are repaired by a variety of pathways within mammalian cells and that the structure of the break or its mode of formation determines its subsequent fate.

Bouffler, S.D.; Jha, B.; Johnson, R.T. (Univ. of Cambridge (England))

1990-09-01

231

Overexpression of ubiquitin carboxyl terminal hydrolase impairs multiple pathways during eye development in Drosophila melanogaster.  

PubMed

UCH-L1 (ubiquitin carboxyl terminal hydrolase L1) is well known as an enzyme that hydrolyzes polyubiquitin at its C-terminal to release ubiquitin monomers. Although the overexpression of UCH-L1 inhibits proteasome activity in cultured cells, its biological significance in living organisms has not been clarified in detail. Here, we utilized Drosophila as a model system to examine the effects of the overexpression of dUCH, a Drosophila homologue of UCH-L1, on development. Overexpression in the eye imaginal discs induced a rough eye phenotype in the adult, at least partly resulting from the induction of caspase-dependent apoptosis followed by compensatory proliferation. Genetic crosses with enhancer trap lines marking the photoreceptor cells also revealed that the overexpression of dUCH specifically impaired R7 photoreceptor cell differentiation with a reduction in activated extracellular-signal-regulated kinase signals. Furthermore, the dUCH-induced rough eye phenotype was rescued by co-expression of the sevenless gene or the Draf gene, a downstream component of the mitogen-activated protein kinase (MAPK) cascade. These results indicate that the overexpression of dUCH impairs R7 photoreceptor cell differentiation by down-regulating the MAPK pathway. Interestingly, this process appears to be independent of its pro-apoptotic function. PMID:22526625

Thao, Dang Thi Phuong; An, Phan Nguyen Thuy; Yamaguchi, Masamitsu; LinhThuoc, Tran

2012-06-01

232

Multiple requirements of the focal dermal hypoplasia gene porcupine during ocular morphogenesis.  

PubMed

Wnt glycoproteins control key processes during development and disease by activating various downstream pathways. Wnt secretion requires post-translational modification mediated by the O-acyltransferase encoded by the Drosophila porcupine homolog gene (PORCN). In humans, PORCN mutations cause focal dermal hypoplasia (FDH, or Goltz syndrome), an X-linked dominant multisystem birth defect that is frequently accompanied by ocular abnormalities such as coloboma, microphthalmia, or even anophthalmia. Although genetic ablation of Porcn in mouse has provided insight into the etiology of defects caused by ectomesodermal dysplasia in FDH, the requirement for Porcn and the actual Wnt ligands during eye development have been unknown. In this study, Porcn hemizygosity occasionally caused ocular defects reminiscent of FDH. Conditional inactivation of Porcn in periocular mesenchyme led to defects in mid- and hindbrain and in craniofacial development, but was insufficient to cause ocular abnormalities. However, a combination of conditional Porcn depletion in optic vesicle neuroectoderm, lens, and neural crest-derived periocular mesenchyme induced severe eye abnormalities with high penetrance. In particular, we observed coloboma, transdifferentiation of the dorsal and ventral retinal pigment epithelium, defective optic cup periphery, and closure defects of the eyelid, as well as defective corneal morphogenesis. Thus, Porcn is required in both extraocular and neuroectodermal tissues to regulate distinct Wnt-dependent processes during morphogenesis of the posterior and anterior segments of the eye. PMID:25451153

Bankhead, Elizabeth J; Colasanto, Mary P; Dyorich, Kayla M; Jamrich, Milan; Murtaugh, L Charles; Fuhrmann, Sabine

2015-01-01

233

Pseudomonas aeruginosa fimL regulates multiple virulence functions by intersecting with Vfr-modulated pathways  

Microsoft Academic Search

Summary Virulence of Pseudomonas aeruginosa involves the co-ordinate expression of a range of factors including type IV pili (tfp), the type III secretion system (TTSS) and quorum sensing. Tfp are required for twitching motility, efficient biofilm formation, and for adhesion and type III secretion (TTS)-mediated damage to mam- malian cells. We describe a novel gene ( fimL ) that is

Cynthia B. Whitchurch; Scott A. Beatson; James C. Comolli; Thania Jakobsen; Jennifer L. Sargent; Jacob J. Bertrand; Joyce West; Mikkel Klausen; Leslie L. Waite; Pil Jung Kang; Tim Tolker-Nielsen; John S. Mattick; Joanne N. Engel

234

Hepatitis C Virus Activates Bcl-2 and MMP-2 Expression through Multiple Cellular Signaling Pathways  

PubMed Central

Hepatitis C virus (HCV) infection is associated with numerous liver diseases and causes serious global health problems, but the mechanisms underlying the pathogenesis of HCV infections remain largely unknown. In this study, we demonstrate that signal transducer and activator of transcription 3 (STAT3), matrix metalloproteinase-2 (MMP-2), and B-cell lymphoma 2 (Bcl-2) are significantly stimulated in HCV-infected patients. We further show that HCV activates STAT3, MMP-2, Bcl-2, extracellular regulated protein kinase (ERK), and c-Jun N-terminal kinase (JNK) in infected Huh7.5.1 cells. Functional screening of HCV proteins revealed that nonstructural protein 4B (NS4B) is responsible for the activation of MMP-2 and Bcl-2 by stimulating STAT3 through repression of the suppressor of cytokine signaling 3 (SOCS3). Our results also demonstrate that multiple signaling cascades, including several members of the protein kinase C (PKC) family, JNK, ERK, and STAT3, play critical roles in the activation of MMP-2 and Bcl-2 mediated by NS4B. Further studies revealed that the C-terminal domain (CTD) of NS4B is sufficient for the activation of STAT3, JNK, ERK, MMP-2, and Bcl-2. We also show that amino acids 227 to 250 of NS4B are essential for regulation of STAT3, JNK, ERK, MMP-2, and Bcl-2, and among them, three residues (237L, 239S, and 245L) are crucial for this regulation. Thus, we reveal a novel mechanism underlying HCV pathogenesis in which multiple intracellular signaling cascades are cooperatively involved in the activation of two important cellular factors, MMP-2 and Bcl-2, in response to HCV infection. PMID:22951829

Li, Youxing; Zhang, Qi; Liu, Yin; Luo, Zhen; Kang, Lei; Qu, Jing; Liu, Weiyong; Xia, Xueshan; Liu, Yingle; Wu, Kailang

2012-01-01

235

Simulating multiple merger pathways to the central kinematics of early-type galaxies  

NASA Astrophysics Data System (ADS)

Two-dimensional integral field surveys such as ATLAS3D are producing rich observational data sets yielding insights into galaxy formation. These new kinematic observations have highlighted the need to understand the evolutionary mechanisms leading to a spectrum of fast rotators and slow rotators in early-type galaxies. We address the formation of slow and fast rotators through a series of controlled, comprehensive hydrodynamical simulations, sampling idealized galaxy merger scenarios constructed from model spiral galaxies. Idealized and controlled simulations of this sort complement the more `realistic' cosmological simulations by isolating and analysing the effects of specific parameters, as we do in this paper. We recreate minor and major binary mergers, binary merger trees with multiple progenitors, and multiple sequential mergers. Within each of these categories of formation history, we correlate progenitor gas fraction, mass ratio, orbital pericentre, orbital ellipticity, and spin with remnant kinematic properties. We create kinematic profiles of these 95 simulations comparable to ATLAS3D data. By constructing remnant profiles of the projected specific angular momentum (? _R= < R|V|rangle / < R ?{V^2+? ^2}rangle), triaxiality, and measuring the incidences of kinematic twists and kinematically decoupled cores, we distinguish between varying formation scenarios. We find that binary mergers nearly always form fast rotators. Slow rotators can be formed from zero initial angular momentum configurations and gas-poor mergers, but are not as round as the ATLAS3D galaxies. Remnants of binary merger trees are triaxial slow rotators. Sequential mergers form round slow rotators that most resemble the ATLAS3D rotators.

Moody, Christopher E.; Romanowsky, Aaron J.; Cox, Thomas J.; Novak, G. S.; Primack, Joel R.

2014-10-01

236

Replication of murine coronavirus requires multiple cysteines in the endodomain of spike protein  

SciTech Connect

A conserved cysteine-rich motif located between the transmembrane domain and the endodomain is essential for membrane fusion and assembly of coronavirus spike (S) protein. Here, we proved that three cysteines within the motif, but not dependent on position, are minimally required for the survival of the recombinant mouse hepatitis virus. When the carboxy termini with these mutated motifs of S proteins were respectively introduced into a heterogeneous protein, both incorporation into lipid rafts and S-palmitoylation of these recombinant proteins showed a similar quantity requirement to cysteine residues. Meanwhile, the redistribution of these proteins on cellular surface indicated that the absence of the positively charged rather than cysteine residues in the motif might lead the dramatic reduction in syncytial formation of some mutants with the deleted motifs. These results suggest that multiple cysteine as well as charged residues concurrently improves the membrane-associated functions of S protein in viral replication and cytopathogenesis.

Yang, Jinhua; Lv, Jun; Wang, Yuyan; Gao, Shuang; Yao, Qianqian; Qu, Di; Ye, Rong, E-mail: yerong24@fudan.edu.cn

2012-06-05

237

Transforming Growth Factor Alpha (TGF?) Regulates Granulosa Cell Tumor (GCT) Cell Proliferation and Migration through Activation of Multiple Pathways  

PubMed Central

Granulosa cell tumors (GCTs) are the most common ovarian estrogen producing tumors, leading to symptoms of excessive estrogen such as endometrial hyperplasia and endometrial adenocarcinoma. These tumors have malignant potential and often recur. The etiology of GCT is unknown. TGF? is a potent mitogen for many different cells. However, its function in GCT initiation, progression and metastasis has not been determined. The present study aims to determine whether TGF? plays a role in the growth of GCT cells. KGN cells, which are derived from an invasive GCT and have many features of normal granulosa cells, were used as the cellular model. Immunohistochemistry, Western blot and RT-PCR results showed that the ErbB family of receptors is expressed in human GCT tissues and GCT cell lines. RT-PCR results also indicated that TGF? and EGF are expressed in the human granulosa cells and the GCT cell lines, suggesting that TGF? might regulate GCT cell function in an autocrine/paracrine manner. TGF? stimulated KGN cell DNA synthesis, cell proliferation, cell viability, cell cycle progression, and cell migration. TGF? rapidly activated EGFR/PI3K/Akt and mTOR pathways, as indicated by rapid phosphorylation of Akt, TSC2, Rictor, mTOR, P70S6K and S6 proteins following TGF? treatment. TGF? also rapidly activated the EGFR/MEK/ERK pathway, and P38 MAPK pathways, as indicated by the rapid phosphorylation of EGFR, MEK, ERK1/2, P38, and CREB after TGF? treatment. Whereas TGF? triggered a transient activation of Akt, it induced a sustained activation of ERK1/2 in KGN cells. Long-term treatment of KGN cells with TGF? resulted in a significant increase in cyclin D2 and a decrease in p27/Kip1, two critical regulators of granulosa cell proliferation and granulosa cell tumorigenesis. In conclusion, TGF?, via multiple signaling pathways, regulates KGN cell proliferation and migration and may play an important role in the growth and metastasis of GCTs. PMID:23155381

Wang, Cheng; Lv, Xiangmin; Jiang, Chao; Cordes, Crystal M.; Fu, Lan; Lele, Subodh M.; Davis, John S.

2012-01-01

238

Proper Actin Ring Formation and Septum Constriction Requires Coordinated Regulation of SIN and MOR Pathways through the Germinal Centre Kinase MST-1  

PubMed Central

Nuclear DBF2p-related (NDR) kinases constitute a functionally conserved protein family of eukaryotic regulators that control cell division and polarity. In fungi, they function as effector kinases of the morphogenesis (MOR) and septation initiation (SIN) networks and are activated by pathway-specific germinal centre (GC) kinases. We characterized a third GC kinase, MST-1, that connects both kinase cascades. Genetic and biochemical interactions with SIN components and life cell imaging identify MST-1 as SIN-associated kinase that functions in parallel with the GC kinase SID-1 to activate the SIN-effector kinase DBF-2. SID-1 and MST-1 are both regulated by the upstream SIN kinase CDC-7, yet in an opposite manner. Aberrant cortical actomyosin rings are formed in ?mst-1, which resulted in mis-positioned septa and irregular spirals, indicating that MST-1-dependent regulation of the SIN is required for proper formation and constriction of the septal actomyosin ring. However, MST-1 also interacts with several components of the MOR network and modulates MOR activity at multiple levels. MST-1 functions as promiscuous enzyme and also activates the MOR effector kinase COT-1 through hydrophobic motif phosphorylation. In addition, MST-1 physically interacts with the MOR kinase POD-6, and dimerization of both proteins inactivates the GC kinase hetero-complex. These data specify an antagonistic relationship between the SIN and MOR during septum formation in the filamentous ascomycete model Neurospora crassa that is, at least in part, coordinated through the GC kinase MST-1. The similarity of the SIN and MOR pathways to the animal Hippo and Ndr pathways, respectively, suggests that intensive cross-communication between distinct NDR kinase modules may also be relevant for the homologous NDR kinases of higher eukaryotes. PMID:24762679

Heilig, Yvonne; Dettmann, Anne; Mouriño-Pérez, Rosa R.; Schmitt, Kerstin; Valerius, Oliver; Seiler, Stephan

2014-01-01

239

Signaling of Chloroquine-Induced Stress in the Yeast Saccharomyces cerevisiae Requires the Hog1 and Slt2 Mitogen-Activated Protein Kinase Pathways  

PubMed Central

Chloroquine (CQ) has been under clinical use for several decades, and yet little is known about CQ sensing and signaling mechanisms or about their impact on various biological pathways. We employed the budding yeast Saccharomyces cerevisiae as a model organism to study the pathways targeted by CQ. Our screening with yeast mutants revealed that it targets histone proteins and histone deacetylases (HDACs). Here, we also describe the novel role of mitogen-activated protein kinases Hog1 and Slt2, which aid in survival in the presence of CQ. Cells deficient in Hog1 or Slt2 are found to be CQ hypersensitive, and both proteins were phosphorylated in response to CQ exposure. CQ-activated Hog1p is translocated to the nucleus and facilitates the expression of GPD1 (glycerol-3-phosphate dehydrogenase), which is required for the synthesis of glycerol (one of the major osmolytes). Moreover, cells treated with CQ exhibited an increase in intracellular reactive oxygen species (ROS) levels and the effects were rescued by addition of reduced glutathione to the medium. The deletion of SOD1, the superoxide dismutase in yeast, resulted in hypersensitivity to CQ. We have also observed P38 as well as P42/44 phosphorylation in HEK293T human cells upon exposure to CQ, indicating that the kinds of responses generated in yeast and human cells are similar. In summary, our findings define the multiple biological pathways targeted by CQ that might be useful for understanding the toxicity modulated by this pharmacologically important molecule. PMID:25022582

Baranwal, Shivani; Azad, Gajendra Kumar; Singh, Vikash

2014-01-01

240

Multiple pathways for l-methionine transport in brush-border membrane vesicles from chicken jejunum  

PubMed Central

The intestinal transport of L-methionine has been investigated in brush-border membrane vesicles isolated from the jejunum of 6-week-old chickens. L-Methionine influx is mediated by passive diffusion and by Na+-dependent and Na+-independent carrier-mediated mechanisms. In the absence of Na+, cis-inhibition experiments with neutral and cationic amino acids indicate that two transport components are involved in L-methionine influx: one sensitive to L-lysine and the other sensitive to 2-aminobicyclo[2.2.1]heptane-2-carboxylic acid (BCH). The L-lysine-sensitive flux is strongly inhibited by L-phenylalanine and can be broken down into two pathways, one sensitive to N-ethylmaleimide (NEM) and the other to L-glutamine and L-cystine. The kinetics of L-methionine influx in Na+-free conditions is described by a model involving three transport systems, here called a,b and c: systems a and b are able to interact with cationic amino acids but differ in their kinetic characteristics (system a: Km= 2.2 ± 0.3 ?M and Vmax= 0.13 ± 0.005 pmol (mg protein)?1 (2 s)?1; system b: Km= 3.0 ± 0.3 mM and Vmax= 465 ± 4.3 pmol (mg protein)?1 (2 s)?1); system c is specific for neutral amino acids, has a Km of 1.29 ± 0.08 mM and a Vmax of 229 ± 5.0 pmol (mg protein)?1 (2 s)?1 and is sensitive to BCH inhibition. The Na+-dependent component can be inhibited by BCH and L-phenylalanine but cannot interact either with cationic amino acids or with ?-(methylamino)isobutyrate (MeAIB). The kinetic analysis of L-methionine influx under a Na+ gradient confirms the activity of the above described transport systems a and b. System a is not affected by the presence of Na+ while system b shows a 3-fold decrease in the Michaelis constant and a 1.4-fold increase in Vmax. In the presence of Na+, the BCH-sensitive component can be subdivided into two pathways: one corresponds to system c and the other is Na+ dependent and has a Km of 0.64 ± 0.013 mM and a Vmax of 391 ± 2.3 pmol (mg protein)?1 (2 s)?1. It is concluded that L-methionine is transported in the chicken jejunum by four transport systems, one with functional characteristics similar to those of system bo, + (system a); a second (system b) similar to system y+, which we suggest naming y+m to account for its high Vmax for L-methionine transport in the absence of Na+; a third (system c) which is Na+ independent and has similar properties to system L; and a fourth showing Na+ dependence and tentatively identified with system B. PMID:9575301

Soriano-García, Juan F; Torras-Llort, Mònica; Ferrer, Ruth; Moretó, Miquel

1998-01-01

241

DBC1 re-expression alters the expression of multiple components of the plasminogen pathway.  

PubMed

Deleted in bladder cancer 1 (DBC1) is a candidate gene for the bladder tumour suppressor locus at 9q33.1. The function of the gene is currently unknown but a cross-species sequence comparison suggests an important role, as it is highly evolutionarily conserved. Here, we transfected a nonexpressing human bladder cancer cell line with a set of human DBC1 cDNA constructs. The effect on global expression patterns was assessed using cDNA microarrays. The cell clone with the lowest level of DBC1 expression showed induced expression of 26 genes including plasminogen activator inhibitor 2 (SERPINB5; 4.6-fold), heparin-binding EGF-like growth factor precursor (DTR; 4.2-fold), small proline-rich protein 2B (SPRR2B; 3.6-fold), metallothionein 1 isoforms (MT1B/MT1A/MT-1F; from 2.9- to 3.2-fold), tissue-type plasminogen activator precursor (PLAT; 2.8-fold) and urokinase-type plasminogen activator precursor (PLAU; 2.7-fold). In clustering analysis, both PLAT and PLAU clustered with the functionally related urokinase plasminogen activator surface receptor (PLAUR; 1.9-fold). Furthermore, 14 human bladder tumours were analysed by real-time quantitative PCR using gene-specific primers for selected (n=20) genes. The expression levels of SERPINB5, PLAU, PLAUR and MT1 correlated with the DBC1 levels, suggesting previously unknown involvement of DBC1 in the urokinase-plasminogen pathway. PMID:16369496

Louhelainen, J P; Hurst, C D; Pitt, E; Nishiyama, H; Pickett, H A; Knowles, M A

2006-04-13

242

Protein Kinase C Activity Is Required for Aryl Hydrocarbon Receptor Pathway-Mediated Signal Transduction  

Microsoft Academic Search

The role of protein kinase C (PKC) in the human aryl hydrocar- bon receptor (hAhR) signal transduction pathway was exam- ined in cell lines stably transfected with pGUDLUC6.1, in which luc1 is solely controlled by four dioxin-responsive elements (DREs). These cell lines, P5A11 and HG40\\/6, were derived from HeLa and HepG2 cells respectively. Simultaneous treatment of these cells with 2,3,7,8,-tetrachlorodibenzo-p-dioxin

WILLIAM PETER LONG; MARILYN PRAY-GRANT; JO CHAO TSAI; GARY H. PERDEW

243

Multiple pathways for uptake of paraquat, methylglyoxal bis(guanylhydrazone), and polyamines  

SciTech Connect

The uptake of polyamines, methylglyoxal bis(guanylhydrazone) (MGBG), and paraquat (N,N-dimethyl-4,4'-bipyridylium) into control Chinese hamster ovary (CHO) cells and a mutant CHO cell line selected for resistance to the toxicity of MGBG was examined. In contrast to control CHO cells, the mutant cells had no detectable uptake of (/sup 14/C)-MGBG or any of the polyamines. There was no difference between the two cell lines in the uptake of ..cap alpha..-aminoisobutyric (/sup 3/H-AIB), which indicates that there was no general change in membrane transport processes. The mutant cells were also found to be resistant to the toxicity of paraquat and to have a reduced capability to take up the herbicide. This finding confirms that the uptake of paraquat is necessary for the toxicity of this compound and that the paraquat is taken up by a transport system that also transports MGBG. Competition experiments showed that an excess of unlabeled paraquat inhibited uptake of MGBG and, to a lesser extent, uptake of putrescine and spermidine, but no inhibitory action on spermine uptake could be detected. Studies with type II cells isolated from rat lung also demonstrated uptake of paraquat and spermidine, but paraquat was only a weak inhibitor of spermidine uptake in this system. These results suggest that there may be multiple systems for the uptake of MGBG and polyamines and that paraquat is taken up by at least one but not by all of these systems.

Byers, T.L.; Kameji, R.; Rannels, D.E.; Pegg, A.E.

1987-06-01

244

T cell-specific inhibition of multiple apoptotic pathways blocks negative selection and causes autoimmunity  

PubMed Central

T cell self-tolerance is thought to involve peripheral tolerance and negative selection, involving apoptosis of autoreactive thymocytes. However, evidence supporting an essential role for negative selection is limited. Loss of Bim, a Bcl-2 BH3-only protein essential for thymocyte apoptosis, rarely results in autoimmunity on the C57BL/6 background. Mice with T cell-specific over-expression of Bcl-2, that blocks multiple BH3-only proteins, are also largely normal. The nuclear receptor Nur77, also implicated in negative selection, might function redundantly to promote apoptosis by associating with Bcl-2 and exposing its potentially pro-apoptotic BH3 domain. Here, we report that T cell-specific expression of a Bcl2 BH3 mutant transgene results in enhanced rescue of thymocytes from negative selection. Concomitantly, Treg development is increased. However, aged BH3 mutant mice progressively accumulate activated, autoreactive T cells, culminating in development of multi-organ autoimmunity and lethality. These data provide strong evidence that negative selection is crucial for establishing T cell tolerance. DOI: http://dx.doi.org/10.7554/eLife.03468.001 PMID:25182415

Burger, Megan L; Leung, Kenneth K; Bennett, Margaux J; Winoto, Astar

2014-01-01

245

Understanding the role of adjunctive nonpharmacological therapies in management of the multiple pathways to depression.  

PubMed

Major depressive disorder (MDD) is a common disorder with a lifetime prevalence of 16.2% and the fourth highest cause of disability globally. It is hypothesized to be a syndromatic manifestation of multiple pathological processes leading to similar clinical manifestation. MDD is associated with at least three categories of peripheral hormone-type factors including neurotrophic factors, proinflammatory cytokines, and processes that impair regulation of the hypothalamic-pituitary-adrenocortical axis. Neuroimaging studies have identified functional abnormalities including subcortical systems associated with reward and emotion processing, medial prefrontal and anterior cingulate cortical regions and the lateral prefrontal cortical systems involved in cognitive control and voluntary emotion regulation. Studies investigating the effects of psychotherapy and pharmacotherapy on functional brain measures show normalization of brain function with return to euthymia. Nevertheless, approximately 50% of patients with MDD will not respond sufficiently and 60 to 70% will not achieve full remission with first-line pharmacotherapy, therefore clinicians strive to improve patient responses through the use of adjunct therapies. This review discusses recent research in the various biological processes associated with MDD as well as recent data in support of the use of adjunctive non-pharmacological therapies including psychotherapy, bibliotherapy, Internet therapy, "natural" or herbal approaches, exercise therapy, and somatic therapies. PMID:25539873

Velehorschi, Corina; Bleau, Pierre; Vermani, Monica; Furtado, Melissa; Klassen, Larry J

2014-12-01

246

Multiple melt extraction pathways beneath Madeira archipelago inferred from barometric studies  

NASA Astrophysics Data System (ADS)

Madeira and the adjacent Desertas islands are interpreted to represent two arms of a volcanic rift system with volcanic activity switching between both arms [1]. The spatial succession is not in accordance with the direction of plate motion, however. To determine if the edifices both represent parts of a single volcanic system, we used fluid inclusion barometry and clinopyroxene-melt thermobarometry to reconstruct the major levels of magma stagnation beneath São Lourenço, representing the Madeira rift zone, and the Desertas rift zone. CO2-dominated fluid inclusions occur in olivine and clinopyroxene phenocrysts. They are, however, more abundant in volcanics from the Desertas islands than São Lourenço. Those of the Desertas islands yield density maxima with corresponding pressure ranges of 0.58-0.7, 0.35-0.52 and 0.05-0.12 GPa (ca. 19-23, 11-17 and 2-4 km). These data indicate that at least three magma stagnation levels exist beneath the Desertas rift zone. Inclusion data from São Lourenço samples show a bimodal density distribution with corresponding pressures of 0.68-0.87 and 0.25-0.34 GPa (ca. 23-29 and 8-11 km). These ranges are displaced to those of the Desertas islands and do not show a shallow pressure level below 0.2 GPa, which implies different magma stagnation levels beneath the two rift systems. Clinopyroxene-melt thermobarometry [2] was applied to Ti-augite phenocryst rim and glass/groundmass compositions. The results indicate equilibrium conditions of 0.5-1 GPa (São Lourenço) and 0.55-0.85 GPa (Desertas islands) in accordance with the deepest levels indicated by fluid inclusion densities. These data are interpreted as fractionation levels in the upper mantle. Compared to the Desertas samples, the São Lourenço rocks show a higher pressure range reflecting deeper magma reservoirs. The different pressure maxima and deeper fractionation levels of São Lourenço clearly show that magma ascent beneath the Desertas rift zone differs from that of the Madeira rift system. The identification of distinct magma pathways down to at least 30 km is hard to reconcile with lateral magma transport. Therefore we propose that Madeira island and the Desertas ridge represent two distinct volcanoes of the Madeira hotspot with separate magma plumbing systems, which were active during the same period. We suggest that these volcanoes root in distinct regions of melt extraction within the ascending plume. [1] Geldmacher J et al. (2000), Geochem Geophys Geosys [2] Putirka K et al. (1996), Contrib Mineral Petrol 123, 92-108

Schwarz, S.; Kluegel, A.

2003-04-01

247

The Hedgehog processing pathway is required for NSCLC growth and survival  

PubMed Central

Considerable interest has been generated from the results of recent clinical trials using SMOOTHENED (SMO) antagonists to inhibit the growth of HEDGEHOG (HH) signaling dependent tumors. This interest is tempered by the discovery of SMO mutations mediating resistance, underscoring the rationale for developing therapeutic strategies that interrupt HH signaling at levels distinct from those inhibiting SMO function. Here, we demonstrate that HH dependent non-small cell lung carcinoma (NSCLC) growth is sensitive to blockade of the HH pathway upstream of SMO, at the level of HH ligand processing. Individually, the use of different lentivirally delivered shRNA constructs targeting two functionally distinct HH-processing proteins, SKINNY HEDGEHOG (SKN) or DISPATCHED-1 (DISP-1), in NSCLC cell lines produced similar decreases in cell proliferation and increased cell death. Further, providing either an exogenous source of processed HH or a SMO agonist reverses these effects. The attenuation of HH processing, by knocking down either of these gene products, also abrogated tumor growth in mouse xenografts. Finally, we extended these findings to primary clinical specimens, showing that SKN is frequently over-expressed in NSCLC and that higher DISP-1 expression is associated with an unfavorable clinical outcome. Our results show a critical role for HH processing in HH-dependent tumors, identifies two potential druggable targets in the HH pathway, and suggest that similar therapeutic strategies could be explored to treat patients harboring HH ligand dependent cancers. PMID:22733134

Rodriguez-Blanco, Jezabel; Schilling, Neal S.; Tokhunts, Robert; Giambelli, Camilla; Long, Jun; Liang Fei, Dennis; Singh, Samer; Black, Kendall E.; Wang, Zhiqiang; Galimberti, Fabrizio; Bejarano, Pablo A.; Elliot, Sharon; Glassberg, Marilyn K.; Nguyen, Dao M.; Lockwood, William W.; Lam, Wan L.; Dmitrovsky, Ethan; Capobianco, Anthony J.; Robbins, David J.

2013-01-01

248

Activation of the MEK pathway is required for complete scattering of MCF7 cells stimulated with heregulin-?1.  

PubMed

Rac1 is important for dissociation of cells during scattering, but whether its activation alone is sufficient to induce complete scattering is not known. To test this, we created an inducible MCF7 cell line that expresses dominant active Rac1. Although induction of dominant active Rac1 resulted in dissociation of cells, their scattering was incomplete. We co-expressed dominant active MKK1a, an activator of ERK, and dominant active Rac1. In this case, cells completely scattered. These results suggest that not only Rac1 but also the MEK1 pathway is required for dissociation and complete scattering of MCF7 cells treated with HRG-?1. PMID:23510995

Chang, Yu-Tsu; Shu, Chung-Li; Fukui, Yasuhisa

2013-04-12

249

Correlations of ion structure with multiple fragmentation pathways arising from collision-induced dissociations of selected ?-hydroxycarboxylic acid anions.  

PubMed

Under conditions of collision-induced dissociation (CID), anions of ?-hydroxycarboxylic acids usually fragment to yield the distinctive hydroxycarbonyl anion (m/z 45) and/or the complementary product anion formed by neutral loss of formic acid (46 u). Further support for the known two-step mechanism, involving an ion-neutral complex for the formation of the hydroxycarbonyl anion from the carboxyl group, is herein provided by tandem mass spectrometric results and density functional theory computations on the glycolate, lactate and 3-phenyllactate ions. A fourth, structurally related ?-hydroxycarboxylate ion, obtained by deprotonation of mandelic acid, showed only loss of carbon dioxide upon CID. Density functional theory computations on the mandelate ion indicated that similar energy inputs were required for a direct, phenyl-assisted decarboxylation and a postulated novel rearrangement to a carbonate ester, which yielded the benzyl oxide ion upon loss of CO2. Rearrangement of the glycolate ion led to expulsion of carbon monoxide, whereas the 3-phenyllactate ion showed the loss of water and formation of the benzyl anion and the benzyl radical as competing processes. The fragmentation pathways proposed for lactate and 3-phenyllactate are supported by isotopic labeling. The relative computed energies of saddle points and product ions for all proposed fragmentation pathways are consistent with the energies supplied during CID experiments and the observed relative intensities of product ions. The diverse reaction pathways characterized for this set of four ?-hydroxycarboxylate ions demonstrate that it is crucial to understand the effects of structural variations when attempting to predict the gas-phase reactivity and CID spectra of carboxylate ions. PMID:23494786

Greene, Lana E; Grossert, J Stuart; White, Robert L

2013-03-01

250

Ablation of Vacuole Protein Sorting 18 (Vps18) Gene Leads to Neurodegeneration and Impaired Neuronal Migration by Disrupting Multiple Vesicle Transport Pathways to Lysosomes*?  

PubMed Central

Intracellular vesicle transport pathways are critical for neuronal survival and central nervous system development. The Vps-C complex regulates multiple vesicle transport pathways to the lysosome in lower organisms. However, little is known regarding its physiological function in mammals. We deleted Vps18, a central member of Vps-C core complex, in neural cells by generating Vps18F/F; Nestin-Cre mice (Vps18 conditional knock-out mice). These mice displayed severe neurodegeneration and neuronal migration defects. Mechanistic studies revealed that Vps18 deficiency caused neurodegeneration by blocking multiple vesicle transport pathways to the lysosome, including autophagy, endocytosis, and biosynthetic pathways. Our study also showed that ablation of Vps18 resulted in up-regulation of ?1 integrin in mouse brain probably due to lysosome dysfunction but had no effects on the reelin pathway, expression of N-cadherin, or activation of JNK, which are implicated in the regulation of neuronal migration. Finally, we demonstrated that knocking down ?1 integrin partially rescued the migration defects, suggesting that Vps18 deficiency-mediated up-regulation of ?1 integrin may contribute to the defect of neuronal migration in the Vps18-deficient brain. Our results demonstrate important roles of Vps18 in neuron survival and migration, which are disrupted in multiple neural disorders. PMID:22854957

Peng, Chao; Ye, Jian; Yan, Shunfei; Kong, Shanshan; Shen, Ye; Li, Chenyu; Li, Qinyu; Zheng, Yufang; Deng, Kejing; Xu, Tian; Tao, Wufan

2012-01-01

251

Mesenchymal stem cells inhibit multiple myeloma cells via the Fas/Fas ligand pathway  

PubMed Central

Introduction Cell-based therapy represents a new frontier in the treatment of a wide variety of human diseases traditionally associated with morbidity outcomes, including those involving inflammation, autoimmunity, tissue damage, and cancer. However, the use of mesenchymal stem cells (MSCs) to treat multiple myeloma (MM) bone disease has raised concerns. Specifically, evidence has shown that infused MSCs might support tumor growth and metastasis. Methods In this study, we used a standard disseminated MM model in mice to identify the in vivo effects of intravenous MSC infusion. In addition, a series of in vitro co-culture assays were preformed to explore whether Fas/Fas ligand (Fas-L) is involved in the inhibitory effects of MSCs on MM cells. Results In the MM mouse model, treatment of MSCs with highly expressed Fas ligand (Fas-Lhigh MSCs) showed remarkable inhibitory effects on MM indenization in terms of extending the mouse survival rate and inhibiting tumor growth, bone resorption in the lumbus and collum femoris, and MM cell metastasis in the lungs and kidneys. In addition, reduced proliferation and increased apoptosis of MM cells was observed when co-cultured with Fas-Lhigh MSCs in vitro. Furthermore, mechanistically, the binding between Fas and Fas-L significantly induced apoptosis in MM cells, as evidenced through an increase in the expression of apoptosis marker and Fas in MM cells. In contrast, Fas-Lnull MSCs promote MM growth. Conclusions These data suggest that Fas/Fas-L-induced MM apoptosis plays a crucial role in the MSC-based inhibition of MM growth. Although whether MSCs inhibit or promote cancer growth remains controversial, the levels of Fas-L expression in MSCs determine, at least partially, the effects of MSCs on MM cell growth. PMID:24025590

2013-01-01

252

Gambogic acid inhibits multiple myeloma mediated osteoclastogenesis through suppression of chemokine receptor CXCR4 signaling pathways.  

PubMed

Bone disease, characterized by the presence of lytic lesions and osteoporosis is the hallmark of multiple myeloma (MM). Stromal cell-derived factor 1? (SDF-1?) and its receptor, CXC chemokine receptor 4 (CXCR4), has been implicated as a regulator of bone resorption, suggesting that agents that can suppress SDF1?/CXCR4 signaling might inhibit osteoclastogenesis, a process closely linked to bone resorption. We, therefore, investigated whether gambogic acid (GA), a xanthone, could inhibit CXCR4 signaling and suppress osteoclastogenesis induced by MM cells. Through docking studies we predicted that GA directly interacts with CXCR4. This xanthone down-regulates the expression of CXCR4 on MM cells in a dose- and time-dependent manner. The down-regulation of CXCR4 was not due to proteolytic degradation, but rather GA suppresses CXCR4 mRNA expression by inhibiting nuclear factor-kappa B (NF-?B) DNA binding. This was further confirmed by quantitative chromatin immunoprecipitation assay, as GA inhibits p65 binding at the CXCR4 promoter. GA suppressed SDF-1?-induced chemotaxis of MM cells and downstream signaling of CXCR4 by inhibiting phosphorylation of Akt, p38, and Erk1/2 in MM cells. GA abrogated the RANKL-induced differentiation of macrophages to osteoclasts in a dose- and time-dependent manner. In addition, we found that MM cells induced differentiation of macrophages to osteoclasts, and that GA suppressed this process. Importantly, suppression of osteoclastogenesis by GA was mediated through IL-6 inhibition. Overall, our results show that GA is a novel inhibitor of CXCR4 expression and has a strong potential to suppress osteoclastogenesis mediated by MM cells. PMID:25034231

Pandey, Manoj K; Kale, Vijay P; Song, Chunhua; Sung, Shen-shu; Sharma, Arun K; Talamo, Giampaolo; Dovat, Sinisa; Amin, Shantu G

2014-10-01

253

Adenovirus RID? uncovers a novel pathway requiring ORP1L for lipid droplet formation independent of NPC1  

PubMed Central

Niemann–Pick disease type C (NPC) is caused by mutations in NPC1 or NPC2, which coordinate egress of low-density-lipoprotein (LDL)-cholesterol from late endosomes. We previously reported that the adenovirus-encoded protein RID? rescues the cholesterol storage phenotype in NPC1-mutant fibroblasts. We show here that RID? reconstitutes deficient endosome-to-endoplasmic reticulum (ER) transport, allowing excess LDL-cholesterol to be esterified by acyl-CoA:cholesterol acyltransferase and stored in lipid droplets (LDs) in NPC1-deficient cells. Furthermore, the RID? pathway is regulated by the oxysterol-binding protein ORP1L. Studies have classified ORP1L as a sterol sensor involved in LE positioning downstream of GTP-Rab7. Our data, however, suggest that ORP1L may play a role in transport of LDL-cholesterol to a specific ER pool designated for LD formation. In contrast to NPC1, which is dispensable, the RID?/ORP1L-dependent route requires functional NPC2. Although NPC1/NPC2 constitutes the major pathway, therapies that amplify minor egress routes for LDL-cholesterol could significantly improve clinical management of patients with loss-of-function NPC1 mutations. The molecular identity of putative alternative pathways, however, is poorly characterized. We propose RID? as a model system for understanding physiological egress routes that use ORP1L to activate ER feedback responses involved in LD formation. PMID:24025716

Cianciola, Nicholas L.; Greene, Diane J.; Morton, Richard E.; Carlin, Cathleen R.

2013-01-01

254

Yeast dom34 mutants are defective in multiple developmental pathways and exhibit decreased levels of polyribosomes.  

PubMed Central

The DOM34 gene of Saccharomyces cerevisiae is similar to genes found in diverse eukaryotes and archaebacteria. Analysis of dom34 strains shows that progression through the G1 phase of the cell cycle is delayed, mutant cells enter meiosis aberrantly, and their ability to form pseudohyphae is significantly diminisehd. RPS30A, which encodes ribosomal protein S30, was identified in a screen for high-copy suppressors of the dom34delta growth defect. dom34delta mutants display an altered polyribosome profile that is rescued by expression of RPS30A. Taken together, these data indicate that Dom34p functions in protein translation to promote G1 progression and differentiation. A Drosophila homolog of Dom34p, pelota, is required for the proper coordination of meiosis and spermatogenesis. Heterologous expression of pelota in dom34delata mutants restores wild-type growth and differentiation, suggesting conservation of function between the eukaryotic members of the gene family. PMID:9584085

Davis, L; Engebrecht, J

1998-01-01

255

Multiple Pathways Are Co-regulated by the Protein Kinase Snf1 and the Transcription Factors Adr1 and Cat8*S  

E-print Network

Multiple Pathways Are Co-regulated by the Protein Kinase Snf1 and the Transcription Factors Adr1 shifted to the aerobic oxidation of non-fermentable carbon sources. The Snf1 protein ki- nase complex on the Snf1 protein kinase for derepression. Many more genes are SNF1-de- pendent than are either ADR1

256

Multiplication  

NSDL National Science Digital Library

Here are some fun games to make practicing multiplication fun!!! Before you start the fun... click Multiplication Tables to review what you already know! Can you figure out the Multiplication Hidden Picture... you better know your math skills first or the picture will burst! It\\'s times to have a \\"blast\\"... Blow me away with theMultiplication Tunnel Blaster Now your ready to join the team! Show me ...

Ms. Walker

2008-03-26

257

Identification and Analyses of AUX-IAA target genes controlling multiple pathways in developing fiber cells of Gossypium hirsutum L  

PubMed Central

Technological development led to an increased interest in systems biological approaches in plants to characterize developmental mechanism and candidate genes relevant to specific tissue or cell morphology. AUX-IAA proteins are important plant-specific putative transcription factors. There are several reports on physiological response of this family in Arabidopsis but in cotton fiber the transcriptional network through which AUX-IAA regulated its target genes is still unknown. in-silico modelling of cotton fiber development specific gene expression data (108 microarrays and 22,737 genes) using Algorithm for the Reconstruction of Accurate Cellular Networks (ARACNe) reveals 3690 putative AUX-IAA target genes of which 139 genes were known to be AUX-IAA co-regulated within Arabidopsis. Further AUX-IAA targeted gene regulatory network (GRN) had substantial impact on the transcriptional dynamics of cotton fiber, as showed by, altered TF networks, and Gene Ontology (GO) biological processes and metabolic pathway associated with its target genes. Analysis of the AUX-IAA-correlated gene network reveals multiple functions for AUX-IAA target genes such as unidimensional cell growth, cellular nitrogen compound metabolic process, nucleosome organization, DNA-protein complex and process related to cell wall. These candidate networks/pathways have a variety of profound impacts on such cellular functions as stress response, cell proliferation, and cell differentiation. While these functions are fairly broad, their underlying TF networks may provide a global view of AUX-IAA regulated gene expression and a GRN that guides future studies in understanding role of AUX-IAA box protein and its targets regulating fiber development. PMID:24497725

Nigam, Deepti; Sawant, Samir V

2013-01-01

258

Multiple Tumor Suppressor microRNAs Regulate Telomerase and TCF7, an Important Transcriptional Regulator of the Wnt Pathway  

PubMed Central

The human TERT (hTERT) gene encodes the telomerase catalytic subunit which plays a role in telomerase regulation. Telomerase is activated in more than 90% of all human malignancies and understanding how telomerase is regulated is necessary for implementation of successful anti-cancer therapies. microRNAs (miRNAs) are important regulators of gene expression in eukaryotic cells but evidence of their role in telomerase regulation has not been documented. To determine whether hTERT activity is regulated by multiple miRNAs, eight miRNAs which have putative binding sites in the hTERT 3?UTR together with miR-138-5p were evaluated in luciferase assays with a reporter containing the hTERT 3?UTR. Six miRNAs (let-7g*, miR-133a, miR-138-5p, miR-342-5p, miR-491-5p, and miR-541-3p) specifically inhibited the expression of the reporter luciferase-driven constructs and let-7g*, miR-133a, miR-138-5p, and miR-491-5p also downregulated endogenous telomerase activity in cells. Moreover, all six miRNAs significantly inhibited cell proliferation. miRNAs (miR-133a, miR-138-5p, 342-5p, 491-5p, 541-3p) also have predicted binding sites within the 3?UTR of three genes involved in Wnt signaling (TCF7, MSI1, and PAX5). These miRNAs inhibited the expression of the luciferase reporter constructs containing 3?UTRs of these genes and downregulated protein expression of the TCF7 transcription factor, which mediates the canonical Wnt pathway. Together, these results suggest the existence of a miRNA regulatory network involving the hTERT and Wnt pathway. PMID:24551047

Bargmann, William; Bose, Henry R.

2014-01-01

259

Paeoniflorin, a natural neuroprotective agent, modulates multiple anti-apoptotic and pro-apoptotic pathways in differentiated PC12 cells.  

PubMed

Numerous studies have shown robust neuroprotective effects of paeoniflorin (PF), a natural compound derived from the herbal medicine Paeony radix. In the present study, we determined associations of PF neuroprotection with its modulation of various apoptotic and anti-apoptotic pathways. PF (50-400 ?M) pretreatment significantly improved viability of differentiated PC12 cells exposed to methyl-4-phenylpyridine ion (MPP(+)), a neurotoxin, and inhibited over-release of lactate dehydrogenase, a biomarker of neuronal cell death. PF also ameliorated MPP(+)-induced nuclear and mitochondrial apoptotic alteration and intracellular calcium overload. PF treatment reversed MPP(+) suppression of activity of B cell lymphoma-extra large, which is a mitochondrial membrane molecule that protects cells from DNA damage-induced apoptosis, and strikingly inhibited the enhanced level of cleaved poly(ADP-ribose)polymerase, which is involved in the process of apoptosis. PF alone and coadministration with MPP(+) enhanced phospho activation of extracellular signal-regulated kinases, Akt, and its downstream element glycogen synthase kinase-3, but the effects were completely abolished in the presence of their blockers PD98059 and LY294002. The presence of the blockers also diminished the potency of PF in improving viability of MPP(+)-exposed cells. These results indicate that neuroprotective effects of PF are related to its modulation of multiple anti-apoptotic and pro-apoptotic pathways, including blockade of intracellular calcium overload, prevention of mitochondrial membrane integrity, inhibition of pro-apoptotic molecules, and up-regulation of anti-apoptotic proteins associated with cell survival and proliferation. The study provides evidence supporting PF as a potential therapeutic agent used for the treatment of neurodegenerative diseases and neural injury. PMID:23436209

Wang, Di; Wong, Hei Kiu; Feng, Yi-Bin; Zhang, Zhang-Jin

2013-05-01

260

Process and utility water requirements for cellulosic ethanol production processes via fermentation pathway  

EPA Science Inventory

The increasing need of additional water resources for energy production is a growing concern for future economic development. In technology development for ethanol production from cellulosic feedstocks, a detailed assessment of the quantity and quality of water required, and the ...

261

Fumonisin B1–Induced Cell Death in Arabidopsis Protoplasts Requires Jasmonate-, Ethylene-, and Salicylate-Dependent Signaling Pathways  

PubMed Central

We have established an Arabidopsis protoplast model system to study plant cell death signaling. The fungal toxin fumonisin B1 (FB1) induces apoptosis-like programmed cell death (PCD) in wild-type protoplasts. FB1, however, only marginally affects the viability of protoplasts isolated from transgenic NahG plants, in which salicylic acid (SA) is metabolically degraded; from pad4-1 mutant plants, in which an SA amplification mechanism is thought to be impaired; or from jar1-1 or etr1-1 mutant plants, which are insensitive to jasmonate (JA) or ethylene (ET), respectively. FB1 susceptibility of wild-type protoplasts decreases in the dark, as does the cellular content of phenylalanine ammonia-lyase, a light-inducible enzyme involved in SA biosynthesis. Interestingly, however, FB1-induced PCD does not require the SA signal transmitter NPR1, given that npr1-1 protoplasts display wild-type FB1 susceptibility. Arabidopsis cpr1-1, cpr6-1, and acd2-2 protoplasts, in which the SA signaling pathway is constitutively activated, exhibit increased susceptibility to FB1. The cpr6-1 and acd2-2 mutants also constitutively express the JA and ET signaling pathways, but only the acd2-2 protoplasts undergo PCD in the absence of FB1. These results demonstrate that FB1 killing of Arabidopsis is light dependent and requires SA-, JA-, and ET-mediated signaling pathways as well as one or more unidentified factors activated by FB1 and the acd2-2 mutation. PMID:11041879

Asai, Tsuneaki; Stone, Julie M.; Heard, Jacqueline E.; Kovtun, Yelena; Yorgey, Peter; Sheen, Jen; Ausubel, Frederick M.

2000-01-01

262

Combinatorial Modulation of Signaling Pathways Reveals Cell-Type-Specific Requirements for Highly Efficient and Synchronous iPSC Reprogramming  

PubMed Central

Summary The differentiated state of somatic cells provides barriers for the derivation of induced pluripotent stem cells (iPSCs). To address why some cell types reprogram more readily than others, we studied the effect of combined modulation of cellular signaling pathways. Surprisingly, inhibition of transforming growth factor ? (TGF-?) together with activation of Wnt signaling in the presence of ascorbic acid allows >80% of murine fibroblasts to acquire pluripotency after 1 week of reprogramming factor expression. In contrast, hepatic and blood progenitors predominantly required only TGF-? inhibition or canonical Wnt activation, respectively, to reprogram at efficiencies approaching 100%. Strikingly, blood progenitors reactivated endogenous pluripotency loci in a highly synchronous manner, and we demonstrate that expression of specific chromatin-modifying enzymes and reduced TGF-?/mitogen-activated protein (MAP) kinase activity are intrinsic properties associated with the unique reprogramming response of these cells. Our observations define cell-type-specific requirements for the rapid and synchronous reprogramming of somatic cells. PMID:25358786

Vidal, Simon E.; Amlani, Bhishma; Chen, Taotao; Tsirigos, Aristotelis; Stadtfeld, Matthias

2014-01-01

263

Combinatorial modulation of signaling pathways reveals cell-type-specific requirements for highly efficient and synchronous iPSC reprogramming.  

PubMed

The differentiated state of somatic cells provides barriers for the derivation of induced pluripotent stem cells (iPSCs). To address why some cell types reprogram more readily than others, we studied the effect of combined modulation of cellular signaling pathways. Surprisingly, inhibition of transforming growth factor ? (TGF-?) together with activation of Wnt signaling in the presence of ascorbic acid allows >80% of murine fibroblasts to acquire pluripotency after 1 week of reprogramming factor expression. In contrast, hepatic and blood progenitors predominantly required only TGF-? inhibition or canonical Wnt activation, respectively, to reprogram at efficiencies approaching 100%. Strikingly, blood progenitors reactivated endogenous pluripotency loci in a highly synchronous manner, and we demonstrate that expression of specific chromatin-modifying enzymes and reduced TGF-?/mitogen-activated protein (MAP) kinase activity are intrinsic properties associated with the unique reprogramming response of these cells. Our observations define cell-type-specific requirements for the rapid and synchronous reprogramming of somatic cells. PMID:25358786

Vidal, Simon E; Amlani, Bhishma; Chen, Taotao; Tsirigos, Aristotelis; Stadtfeld, Matthias

2014-10-14

264

Model-Derived Dispersal Pathways from Multiple Source Populations Explain Variability of Invertebrate Larval Supply  

PubMed Central

Background Predicting the spatial and temporal patterns of marine larval dispersal and supply is a challenging task due to the small size of the larvae and the variability of oceanographic processes. Addressing this problem requires the use of novel approaches capable of capturing the inherent variability in the mechanisms involved. Methodology/Principal Findings In this study we test whether dispersal and connectivity patterns generated from a bio-physical model of larval dispersal of the crab Carcinus maenas, along the west coast of the Iberian Peninsula, can predict the highly variable daily pattern of wind-driven larval supply to an estuary observed during the peak reproductive season (March–June) in 2006 and 2007. Cross-correlations between observed and predicted supply were significant (p<0.05) and strong, ranging from 0.34 to 0.81 at time lags of ?6 to +5 d. Importantly, the model correctly predicted observed cross-shelf distributions (Pearson r?=?0.82, p<0.001, and r?=?0.79, p<0.01, in 2006 and 2007) and indicated that all supply events were comprised of larvae that had been retained within the inner shelf; larvae transported to the outer shelf and beyond never recruited. Estimated average dispersal distances ranged from 57 to 198 km and were only marginally affected by mortality. Conclusions/Significance The high degree of predicted demographic connectivity over relatively large geographic scales is consistent with the lack of genetic structuring in C. maenas along the Iberian Peninsula. These findings indicate that the dynamic nature of larval dispersal can be captured by mechanistic biophysical models, which can be used to provide meaningful predictions of the patterns and causes of fine-scale variability in larval supply to marine populations. PMID:22558225

Domingues, Carla P.; Nolasco, Rita; Dubert, Jesus; Queiroga, Henrique

2012-01-01

265

Uterine Rbpj is required for embryonic-uterine orientation and decidual remodeling via Notch pathway-independent and -dependent mechanisms  

PubMed Central

Coordinated uterine-embryonic axis formation and decidual remodeling are hallmarks of mammalian post-implantation embryo development. Embryonic-uterine orientation is determined at initial implantation and synchronized with decidual development. However, the molecular mechanisms controlling these events remain elusive despite its discovery a long time ago. In the present study, we found that uterine-specific deletion of Rbpj, the nuclear transducer of Notch signaling, resulted in abnormal embryonic-uterine orientation and decidual patterning at post-implantation stages, leading to substantial embryo loss. We further revealed that prior to embryo attachment, Rbpj confers on-time uterine lumen shape transformation via physically interacting with uterine estrogen receptor (ER?) in a Notch pathway-independent manner, which is essential for the initial establishment of embryo orientation in alignment with uterine axis. While at post-implantation stages, Rbpj directly regulates the expression of uterine matrix metalloproteinase in a Notch pathway-dependent manner, which is required for normal post-implantation decidual remodeling. These results demonstrate that uterine Rbpj is essential for normal embryo development via instructing the initial embryonic-uterine orientation and ensuring normal decidual patterning in a stage-specific manner. Our data also substantiate the concept that normal mammalian embryonic-uterine orientation requires proper guidance from developmentally controlled uterine signaling. PMID:24971735

Zhang, Shuang; Kong, Shuangbo; Wang, Bingyan; Cheng, Xiaohong; Chen, Yongjie; Wu, Weiwei; Wang, Qiang; Shi, Junchao; Zhang, Ying; Wang, Shumin; Lu, Jinhua; Lydon, John P; DeMayo, Francesco; Pear, Warren S; Han, Hua; Lin, Haiyan; Li, Lei; Wang, Hongmei; Wang, Yan-ling; Li, Bing; Chen, Qi; Duan, Enkui; Wang, Haibin

2014-01-01

266

Uterine Rbpj is required for embryonic-uterine orientation and decidual remodeling via Notch pathway-independent and -dependent mechanisms.  

PubMed

Coordinated uterine-embryonic axis formation and decidual remodeling are hallmarks of mammalian post-implantation embryo development. Embryonic-uterine orientation is determined at initial implantation and synchronized with decidual development. However, the molecular mechanisms controlling these events remain elusive despite its discovery a long time ago. In the present study, we found that uterine-specific deletion of Rbpj, the nuclear transducer of Notch signaling, resulted in abnormal embryonic-uterine orientation and decidual patterning at post-implantation stages, leading to substantial embryo loss. We further revealed that prior to embryo attachment, Rbpj confers on-time uterine lumen shape transformation via physically interacting with uterine estrogen receptor (ER?) in a Notch pathway-independent manner, which is essential for the initial establishment of embryo orientation in alignment with uterine axis. While at post-implantation stages, Rbpj directly regulates the expression of uterine matrix metalloproteinase in a Notch pathway-dependent manner, which is required for normal post-implantation decidual remodeling. These results demonstrate that uterine Rbpj is essential for normal embryo development via instructing the initial embryonic-uterine orientation and ensuring normal decidual patterning in a stage-specific manner. Our data also substantiate the concept that normal mammalian embryonic-uterine orientation requires proper guidance from developmentally controlled uterine signaling. PMID:24971735

Zhang, Shuang; Kong, Shuangbo; Wang, Bingyan; Cheng, Xiaohong; Chen, Yongjie; Wu, Weiwei; Wang, Qiang; Shi, Junchao; Zhang, Ying; Wang, Shumin; Lu, Jinhua; Lydon, John P; DeMayo, Francesco; Pear, Warren S; Han, Hua; Lin, Haiyan; Li, Lei; Wang, Hongmei; Wang, Yan-Ling; Li, Bing; Chen, Qi; Duan, Enkui; Wang, Haibin

2014-08-01

267

Klf5 Deletion Promotes Pten Deletion–Initiated Luminal-Type Mouse Prostate Tumors through Multiple Oncogenic Signaling Pathways12  

PubMed Central

Krüppel-like factor 5 (KLF5) regulates multiple biologic processes. Its function in tumorigenesis appears contradictory though, showing both tumor suppressor and tumor promoting activities. In this study, we examined whether and how Klf5 functions in prostatic tumorigenesis using mice with prostate-specific deletion of Klf5 and phosphatase and tensin homolog (Pten), both of which are frequently inactivated in human prostate cancer. Histologic analysis demonstrated that when one Pten allele was deleted, which causes mouse prostatic intraepithelial neoplasia (mPIN), Klf5 deletion accelerated the emergence and progression of mPIN. When both Pten alleles were deleted, which causes prostate cancer, Klf5 deletion promoted tumor growth, increased cell proliferation, and caused more severe morphologic and molecular alterations. Homozygous deletion of Klf5 was more effective than hemizygous deletion. Unexpectedly, while Pten deletion alone expanded basal cell population in a tumor as reported, Klf5 deletion in the Pten-null background clearly reduced basal cell population while expanding luminal cell population. Global gene expression profiling, pathway analysis, and experimental validation indicate that multiple mechanisms could mediate the tumor-promoting effect of Klf5 deletion, including the up-regulation of epidermal growth factor and its downstream signaling molecules AKT and ERK and the inactivation of the p15 cell cycle inhibitor. KLF5 also appears to cooperate with several transcription factors, including CREB1, Sp1, Myc, ER and AR, to regulate gene expression. These findings validate the tumor suppressor function of KLF5. They also yield a mouse model that shares two common genetic alterations with human prostate cancer—mutation/deletion of Pten and deletion of Klf5. PMID:25425963

Xing, Changsheng; Ci, Xinpei; Sun, Xiaodong; Fu, Xiaoying; Zhang, Zhiqian; Dong, Eric N.; Hao, Zhao-Zhe; Dong, Jin-Tang

2014-01-01

268

A calmodulin-binding/CGCG box DNA-binding protein family involved in multiple signaling pathways in plants  

NASA Technical Reports Server (NTRS)

We reported earlier that the tobacco early ethylene-responsive gene NtER1 encodes a calmodulin-binding protein (Yang, T., and Poovaiah, B. W. (2000) J. Biol. Chem. 275, 38467-38473). Here we demonstrate that there is one NtER1 homolog as well as five related genes in Arabidopsis. These six genes are rapidly and differentially induced by environmental signals such as temperature extremes, UVB, salt, and wounding; hormones such as ethylene and abscisic acid; and signal molecules such as methyl jasmonate, H(2)O(2), and salicylic acid. Hence, they were designated as AtSR1-6 (Arabidopsis thaliana signal-responsive genes). Ca(2+)/calmodulin binds to all AtSRs, and their calmodulin-binding regions are located on a conserved basic amphiphilic alpha-helical motif in the C terminus. AtSR1 targets the nucleus and specifically recognizes a novel 6-bp CGCG box (A/C/G)CGCG(G/T/C). The multiple CGCG cis-elements are found in promoters of genes such as those involved in ethylene signaling, abscisic acid signaling, and light signal perception. The DNA-binding domain in AtSR1 is located on the N-terminal 146 bp where all AtSR1-related proteins share high similarity but have no similarity to other known DNA-binding proteins. The calmodulin-binding nuclear proteins isolated from wounded leaves exhibit specific CGCG box DNA binding activities. These results suggest that the AtSR gene family encodes a family of calmodulin-binding/DNA-binding proteins involved in multiple signal transduction pathways in plants.

Yang, Tianbao; Poovaiah, B. W.

2002-01-01

269

Alterations in K-ras, APC and p53-multiple genetic pathway in colorectal cancer among Indians.  

PubMed

The incidence of colorectal cancer (CRC) is increasing rapidly in Asian countries during the past few decades, but no comprehensive analysis has been done to find out the exact cause of this disease. In this study, we investigated the frequencies of mutations and expression pattern of K-ras, APC (adenomatosis polyposis coli) and p53 in tumor, adjoining and distant normal mucosa and to correlate these alterations with patients clinicopathological parameters as well as with the survival. Polymerase chain reaction (PCR)-restriction digestion was used to detect mutations in K-ras and PCR-SSCP (Single Strand Conformation Polymorphism) followed by DNA sequencing was used to detect mutations in APC and p53 genes. Immunohistochemistry was used to detect the expression pattern of K-ras, APC and p53 proteins. The frequencies of mutations of K-ras, APC and p53 in 30 tumor tissues samples were 26.7 %, 46.7 % and 20 %, respectively. Only 3.3 % of tumors contained mutations in all the three genes. The most common combination of mutation was APC and p53 whereas mutation in both p53 and K-ras were extremely rare. There was no association between the mutations and expression pattern of K-ras, APC and p53 (p>0.05). In Indians, the frequency of alterations of K-ras and APC is similar as in Westerns, whereas the frequency of p53 mutation is slightly lower. The lack of multiple mutations in tumor specimens suggests that these genetic alterations might have independent influences on CRC development and there could be multiple alternative genetic pathways to CRC in our present study cohort. PMID:23526092

Malhotra, Pooja; Anwar, Mumtaz; Nanda, Neha; Kochhar, Rakesh; Wig, Jai Dev; Vaiphei, Kim; Mahmood, Safrun

2013-06-01

270

AtGSNOR1 function is required for multiple developmental programs in Arabidopsis.  

PubMed

Nitric oxide (NO) has been proposed to regulate a diverse array of activities during plant growth, development and immune function. S-nitrosylation, the addition of an NO moiety to a reactive cysteine thiol, to form an S-nitrosothiol (SNO), is emerging as a prototypic redox-based post-translational modification. An ARABIDOPSIS THALIANA S-NITROSOGLUTATHIONE (GSNO) REDUCTASE (AtGSNOR1) is thought to be the major regulator of total cellular SNO levels in this plant species. Here, we report on the impact of loss- and gain-of-function mutations in AtGSNOR1 upon plant growth and development. Loss of AtGSNOR1 function in atgsnor1-3 plants increased the number of initiated higher order axillary shoots that remain active, resulting in a loss of apical dominance relative to wild type. In addition atgsnor1-3 affected leaf shape, germination, 2,4-D sensitivity and reduced hypocotyl elongation in both light and dark grown seedlings. Silique size and seed production were also decreased in atgsnor1-3 plants and the latter was reduced in atgsnor1-1 plants, which overexpress AtGSNOR1. Overexpression of AtGSNOR1 slightly delayed flowering time in both long and short days, whereas atgsnor1-3 showed early flowering compared to wild type. In the atgsnor1-3 line, FLOWERING LOCUS C (FLC) expression was reduced, whereas transcription of CONSTANS (CO) was enhanced. Therefore, AtGSNOR1 may negatively regulate the autonomous and photoperiod flowering time pathways. Both overexpression and loss of AtGSNOR1 function also reduced primary root growth, while root hair development was increased in atgsnor1-1 and reduced in atgsnor1-3 plants. Collectively, our findings imply that AtGSNOR1 controls multiple genetic networks integral to plant growth and development. PMID:22767201

Kwon, Eunjung; Feechan, Angela; Yun, Byung-Wook; Hwang, Byung-Ho; Pallas, Jacqueline A; Kang, Jeong-Gu; Loake, Gary J

2012-09-01

271

Nuclear import of the yeast hexokinase 2 protein requires ?/?-importin-dependent pathway.  

PubMed

Hexokinase 2 (Hxk2) from Saccharomyces cerevisiae was one of the first metabolic enzymes described as a multifunctional protein. Hxk2 has a double subcellular localization and role, it functions as a glycolytic enzyme in the cytoplasm and as a regulator of gene transcription of several Mig1-regulated genes in the nucleus. However, the mechanism by which Hxk2 enters in the nucleus was unknown until now. Here, we report that the Hxk2 protein is an import substrate of the carriers ?-importin (Kap60 in yeast) and ?-importin (Kap95 in yeast). We also show that the Hxk2 nuclear import and the binding of Hxk2 with Kap60 are glucose-dependent and involve one lysine-rich nuclear localization sequence (NLS), located between lysine 6 and lysine 12. Moreover, Kap95 facilitates the recognition of the Hxk2 NLS1 motif by Kap60 and both importins are essential for Hxk2 nuclear import. It is also demonstrated that Hxk2 nuclear import and its binding to Kap95 and Kap60 depend on the Gsp1-GTP/GDP protein levels. Thus, our study uncovers Hxk2 as a new cargo for the ?/?-importin pathway of S. cerevisiae. PMID:22157003

Peláez, Rafael; Fernández-García, Paula; Herrero, Pilar; Moreno, Fernando

2012-01-27

272

A decision analysis approach to climate adaptation: comparing multiple pathways for multi-decadal decision making  

NASA Astrophysics Data System (ADS)

Policy planners around the world are required to consider the implications of adapting to climatic change across spatial contexts and decadal timeframes. However, local level information for planning is often poorly defined, even though climate adaptation decision-making is made at this scale. This is especially true when considering sea level rise and coastal impacts of climate change. We present a simple approach using sea level rise simulations paired with adaptation scenarios to assess a range of adaptation options available to local councils dealing with issues of beach recession under present and future sea level rise and storm surge. Erosion and beach recession pose a large socioeconomic risk to coastal communities because of the loss of key coastal infrastructure. We examine the well-known adaptation technique of beach nourishment and assess various timings and amounts of beach nourishment at decadal time spans in relation to beach recession impacts. The objective was to identify an adaptation strategy that would allow for a low frequency of management interventions, the maintenance of beach width, and the ability to minimize variation in beach width over the 2010 to 2100 simulation period. 1000 replications of each adaptation option were produced against the 90 year simulation in order to model the ability each adaptation option to achieve the three key objectives. Three sets of adaptation scenarios were identified. Within each scenario, a number of adaptation options were tested. The three scenarios were: 1) Fixed periodic beach replenishment of specific amounts at 20 and 50 year intervals, 2) Beach replenishment to the initial beach width based on trigger levels of recession (5m, 10m, 20m), and 3) Fixed period beach replenishment of a variable amount at decadal intervals (every 10, 20, 30, 40, 50 years). For each adaptation option, we show the effectiveness of each beach replenishment scenario to maintain beach width and consider the implications of more frequent replenishment with that of implementation cost. We determine that a business as usual scenario, where no adaptation is implemented, would lead to an average beach recession of 12.02 meters and a maximum beach recession of 33.23 meters during the period of 2010-2100. The best adaptation option modeled was a fixed replenishment of 5 meters every 20 years leading to 4 replenishment events with an average beach recession of 2.99 meters and a maximum beach recession of 15.02 meters during the period of 2010-2100. The presented simulations explicitly address the uncertainty of future impacts due to sea level rise and storm surge and show a range of options that could be considered by a local council to meet their policy objectives. The simulation runs provide managers the ability to consider the utility of various adaptation options and the timing and costs of implementation. Such information provides an evidence-based practice to decision-making and allows policy makers to transparently make decisions based on best estimates of modeled climate change.

Lin, B. B.; Little, L.

2013-12-01

273

Canonical Wnt Pathway Inhibitor ICG-001 Induces Cytotoxicity of Multiple Myeloma Cells in Wnt-Independent Manner  

PubMed Central

Canonical Wnt signaling has been implicated in the regulation of multiple myeloma (MM) growth. Here, we investigated whether the targeting of this pathway with a novel pharmacological inhibitor ICG-001 would result in an anti-tumor effect and improvement of chemosensitivity in MM. As expected, ICG-001 specifically down-regulated ?-catenin/TCF-mediated transcription in MM cells. Treatment with ICG-001 resulted in growth arrest and apoptosis in MM cell lines and primary MM cells. Moreover, ICG-001 enhanced the cytotoxic effects of doxorubicin and melphalan and abrogated chemoresistance of MM cells to these chemotherapeutics induced by bone marrow stroma. The cytotoxic effect of ICG-001 was caspase-dependent and mediated through transcriptional up-regulation of BH3-only pro-apoptotic members of the Bcl-2 family Noxa and Puma but not through inhibition of canonical Wnt signaling. ICG-001 selectively induced apoptosis in primary MM cells but did not affect non-MM cells of the bone marrow microenvironment. Experiments using a xenograft model of MM showed substantial anti-tumor effects of this compound in vivo. Thus, our study demonstrated that the small molecule inhibitor ICG-001 has strong anti-MM effects and could be developed further for therapeutic intervention in this disease. PMID:25635944

Grigson, Eileen R.; Ozerova, Maria; Pisklakova, Alexandra; Liu, Hao; Sullivan, Daniel M.; Nefedova, Yulia

2015-01-01

274

Recombinant bovine neurokinin-2 receptor stably expressed in Chinese hamster ovary cells couples to multiple signal transduction pathways.  

PubMed Central

Neurokinins are a family of neuropeptides with widespread distribution mediating a broad spectrum of physiological actions through three distinct receptor subtypes: NK-1, NK-2, and NK-3. We investigated some of the second messenger and cellular processes under control by the recombinant bovine NK-2 receptor stably expressed in Chinese hamster ovary cells. In this system the NK-2 receptor displays its expected pharmacological characteristics, and the physiological agonist neurokinin A stimulates several cellular responses. These include 1) transient inositol 1,4,5-trisphosphate (IP3) formation and Ca2+ mobilization, 2) increased out put of arachidonic acid and prostaglandin E2 (PGE2), 3) enhanced cyclic AMP (cAMP) generation, 4) increased de novo DNA synthesis, and 5) an induction of the "immediate early" genes c-fos and c-jun. Although NK-2 receptor-mediated IP3 formation involves activation of a pertussis toxin-insensitive G-protein, increased cAMP production is largely a secondary response and can be at least partially attributed to autocrine stimulation by endogenously generated eicosanoids, particularly PGE2. This is the first demonstration that a single recombinant neurokinin receptor subtype can regulate, either directly or indirectly, multiple signal transduction pathways and suggests several potential important mediators of neurokinin actions under physiological conditions. Images PMID:1666301

Eistetter, H R; Church, D J; Mills, A; Godfrey, P P; Capponi, A M; Brewster, R; Schulz, M F; Kawashima, E; Arkinstall, S J

1991-01-01

275

Interpretation and applicability of empirical tissue enhancement metrics in dynamic contrast-enhanced MRI based on a multiple pathway model  

NASA Astrophysics Data System (ADS)

Computer simulations based on a physiologically realistic tracer kinetic model with multiple pathways was used to provide insights on the applicability and interpretation of tissue enhancement metrics such as the maximum slope, peak enhancement and area under curve, commonly used in dynamic contrast-enhanced (DCE) MRI. Results show that physiological conditions of the tissue that could affect the accuracy of the maximal slope method include a high blood flow, increased variability of flow within the vasculature or a low vascular volume. Interestingly, changes in permeability and interstitial volume might not affect the accuracy of the maximal slope method. Time-to-peak and peak value of the tissue enhancement curve are not strictly properties of the tissue alone, and they cannot be linearly related to intrinsic tissue parameters such as blood flow, blood volume, capillary permeability, interstitial volume and mean transit time. Similar to the normalized initial area under tissue concentration curve, an alternative estimate of the total tracer distribution volume can be simply given by the ratio of tracer concentration in the tissue and artery sampled at the final DCE scan.

Koh, T. S.; Shi, W.; Thng, C. H.; Kwek, J. W.; Bisdas, S.; Khoo, J. B. K.

2012-08-01

276

Intranasal deferoxamine engages multiple pathways to decrease memory loss in the APP/PS1 model of amyloid accumulation.  

PubMed

In addition to the hallmark accumulation of amyloid and hyper-phosphorylation of tau, brain changes in Alzheimer's disease are multifactorial including inflammation, oxidative stress, and metal dysregulation. Metal chelators have been explored as a less well known approach to treatment. One chelator currently being developed is deferoxamine (DFO), administered via the intranasal (IN) route. In the current study, APP/PS1 amyloid mice were treated with a chronic, low dose of IN DFO, subjected to a rigorous battery of behavior tests, and the mechanism of action was examined. Mice were treated 3x/week with 0.24 C IN DFO for 18 weeks from 36 to 54 weeks of age, 4 weeks of behavior tests were performed that included both working and reference memory, anxiolytic and motor behaviors, and finally brain tissues were analyzed for amyloid, protein oxidation, and other proteins affected by DFO. We found that IN DFO treatment significantly decreased loss of both reference and working memory in the Morris and radial arm water mazes (p < 0.05), and also decreased soluble A?40 and A?42 in cortex and hippocampus (p < 0.05). Further, IN DFO decreased activity of GSK3?, and led to decreases in oxidative stress (p < 0.05). These data demonstrate that low doses of IN DFO can modify several targets along the multiple pathways implicated in the neuropathology of Alzheimer's, making it an attractive candidate for the treatment of this heterogeneous disease. PMID:25445365

Fine, Jared M; Renner, Daniel B; Forsberg, Anna C; Cameron, Rachel A; Galick, Benjamin T; Le, Clint; Conway, Patrick M; Stroebel, Benjamin M; Frey, William H; Hanson, Leah R

2015-01-01

277

Canonical Wnt pathway inhibitor ICG-001 induces cytotoxicity of multiple myeloma cells in Wnt-independent manner.  

PubMed

Canonical Wnt signaling has been implicated in the regulation of multiple myeloma (MM) growth. Here, we investigated whether the targeting of this pathway with a novel pharmacological inhibitor ICG-001 would result in an anti-tumor effect and improvement of chemosensitivity in MM. As expected, ICG-001 specifically down-regulated ?-catenin/TCF-mediated transcription in MM cells. Treatment with ICG-001 resulted in growth arrest and apoptosis in MM cell lines and primary MM cells. Moreover, ICG-001 enhanced the cytotoxic effects of doxorubicin and melphalan and abrogated chemoresistance of MM cells to these chemotherapeutics induced by bone marrow stroma. The cytotoxic effect of ICG-001 was caspase-dependent and mediated through transcriptional up-regulation of BH3-only pro-apoptotic members of the Bcl-2 family Noxa and Puma but not through inhibition of canonical Wnt signaling. ICG-001 selectively induced apoptosis in primary MM cells but did not affect non-MM cells of the bone marrow microenvironment. Experiments using a xenograft model of MM showed substantial anti-tumor effects of this compound in vivo. Thus, our study demonstrated that the small molecule inhibitor ICG-001 has strong anti-MM effects and could be developed further for therapeutic intervention in this disease. PMID:25635944

Grigson, Eileen R; Ozerova, Maria; Pisklakova, Alexandra; Liu, Hao; Sullivan, Daniel M; Nefedova, Yulia

2015-01-01

278

49 CFR 234.306 - Multiple dispatching or maintaining railroads with respect to the same highway-rail or pathway...  

Code of Federal Regulations, 2012 CFR

...railroads with respect to the same highway-rail or pathway grade crossing; appointment...Reporting of Unsafe Conditions at Highway-Rail and Pathway Grade Crossings § 234.306...railroads with respect to the same highway-rail or pathway grade crossing;...

2012-10-01

279

49 CFR 234.306 - Multiple dispatching or maintaining railroads with respect to the same highway-rail or pathway...  

Code of Federal Regulations, 2013 CFR

...railroads with respect to the same highway-rail or pathway grade crossing; appointment...Reporting of Unsafe Conditions at Highway-Rail and Pathway Grade Crossings § 234.306...railroads with respect to the same highway-rail or pathway grade crossing;...

2013-10-01

280

49 CFR 234.306 - Multiple dispatching or maintaining railroads with respect to the same highway-rail or pathway...  

Code of Federal Regulations, 2014 CFR

...railroads with respect to the same highway-rail or pathway grade crossing; appointment...Reporting of Unsafe Conditions at Highway-Rail and Pathway Grade Crossings § 234.306...railroads with respect to the same highway-rail or pathway grade crossing;...

2014-10-01

281

Higher biodiversity is required to sustain multiple ecosystem processes across temperature regimes  

PubMed Central

Biodiversity loss is occurring rapidly worldwide, yet it is uncertain whether few or many species are required to sustain ecosystem functioning in the face of environmental change. The importance of biodiversity might be enhanced when multiple ecosystem processes (termed multifunctionality) and environmental contexts are considered, yet no studies have quantified this explicitly to date. We measured five key processes and their combined multifunctionality at three temperatures (5, 10 and 15 °C) in freshwater aquaria containing different animal assemblages (1–4 benthic macroinvertebrate species). For single processes, biodiversity effects were weak and were best predicted by additive-based models, i.e. polyculture performances represented the sum of their monoculture parts. There were, however, significant effects of biodiversity on multifunctionality at the low and the high (but not the intermediate) temperature. Variation in the contribution of species to processes across temperatures meant that greater biodiversity was required to sustain multifunctionality across different temperatures than was the case for single processes. This suggests that previous studies might have underestimated the importance of biodiversity in sustaining ecosystem functioning in a changing environment. PMID:25131335

Perkins, Daniel M; Bailey, R A; Dossena, Matteo; Gamfeldt, Lars; Reiss, Julia; Trimmer, Mark; Woodward, Guy

2015-01-01

282

Fluxes of Ca2+ and K+ Are Required for the Listeriolysin O-Dependent Internalization Pathway of Listeria monocytogenes  

PubMed Central

Listeria monocytogenes is responsible for the life-threatening food-borne disease listeriosis. This disease mainly affects elderly and immunocompromised individuals, causing bacteremia and meningoencephalitis. In pregnant women, L. monocytogenes infection leads to abortion and severe infection of the fetus or newborn. The L. monocytogenes intracellular life cycle is critical for pathogenesis. Previous studies have established that the major virulence factor of L. monocytogenes, the pore-forming toxin listeriolysin O (LLO), is sufficient to induce L. monocytogenes internalization into human epithelial cell lines. This internalization pathway strictly requires the formation of LLO pores in the plasma membrane and can be stimulated by the heterologous pore-forming toxin pneumolysin, suggesting that LLO acts nonspecifically by forming transmembrane pores. The present work tested the hypothesis that Ca2+ and K+ fluxes subsequent to perforation by LLO control L. monocytogenes internalization. We report that L. monocytogenes perforates the host cell plasma membrane in an LLO-dependent fashion at the early stage of invasion. In response to perforation, host cells undergo Ca2+-dependent but K+-independent resealing of their plasma membrane. In contrast to the plasma membrane resealing process, LLO-induced L. monocytogenes internalization requires both Ca2+ and K+ fluxes. Further linking ion fluxes to bacterial internalization, treating cells with a combination of Ca2+ and K+ ionophores but not with individual ionophores is sufficient to induce efficient internalization of large cargoes, such as 1-?m polystyrene beads and bacteria. We propose that LLO-induced L. monocytogenes internalization requires a Ca2+- and K+-dependent internalization pathway that is mechanistically distinct from the process of plasma membrane resealing. PMID:24366251

Vadia, Stephen

2014-01-01

283

P38 AND EGF RECEPTOR KINASE-MEDIATED ACTIVATION OF THE PHOSPHATIDYLINOSITOL 3-KINASE/AKT PATHWAY IS REQUIRED FOR ZN2+INDUCED CYCLOOXYGENASE-2 EXPRESSION  

EPA Science Inventory

Cyclooxygenase 2 (COX-2) expression is induced by physiological and inflammatory stimuli. Regulation of COX-2 expression is stimulus- and cell type-specific. Exposure to Zn2+ has been associated with activation of multiple intracellular signaling pathways as well as the induction...

284

Structural Requirements and Reaction Pathways in Dimethyl Ether Combustion Catalyzed by Supported Pt Clusters  

SciTech Connect

The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. The identity and reversibility of the elementary steps required for catalytic combustion of dimethyl ether (DME) on Pt clusters were determined by combining isotopic and kinetic analyses with density functional theory estimates of reaction energies and activation barriers to probe the lowest energy paths. Reaction rates are limited by C-H bond activation in DME molecules adsorbed on surfaces of Pt clusters containing chemisorbed oxygen atoms at near-saturation coverages. Reaction energies and activation barriers for C-H bond activation in DME to form methoxymethyl and hydroxyl surface intermediates show that this step is more favorable than the activation of C-O bonds to form two methoxides, consistent with measured rates and kinetic isotope effects. This kinetic preference is driven by the greater stability of the CH3OCH2* and OH* intermediates relative to chemisorbed methoxides. Experimental activation barriers on Pt clusters agree with density functional theory (DFT)-derived barriers on oxygen-covered Pt(111). Measured DME turnover rates increased with increasing DME pressure, but decreased as the O2 pressure increased, because vacancies (*) on Pt surfaces nearly saturated with chemisorbed oxygen are required for DME chemisorption. DFT calculations show that although these surface vacancies are required, higher oxygen coverages lead to lower C-H activation barriers, because the basicity of oxygen adatoms increases with coverage and they become more effective in hydrogen abstraction from DME. Water inhibits reaction rates via quasi-equilibrated adsorption on vacancy sites, consistent with DFT results indicating that water binds more strongly than DME on vacancies. These conclusions are consistent with the measured kinetic response of combustion rates to DME, O2, and H2O, with H/D kinetic isotope effects, and with the absence of isotopic scrambling in reactants containing isotopic mixtures of 18O2-16O2 or 12CH3O12CH3-13CH3O13- CH3. Turnover rates increased with Pt cluster size, because small clusters, with more coordinatively unsaturated surface atoms, bind oxygen atoms more strongly than larger clusters and exhibit lower steadystate vacancy concentrations and a consequently smaller number of adsorbed DME intermediates involved in kinetically relevant steps. These effects of cluster size and metal-oxygen bond energies on reactivity are ubiquitous in oxidation reactions requiring vacancies on surfaces nearly saturated with intermediates derived from O2.

Ishikawa, Akio; Neurock, Matthew; Iglesia, Enrique

2007-10-31

285

Structural requirements and reaction pathways in dimethyl ether combustion catalyzed by supported Pt clusters.  

PubMed

The identity and reversibility of the elementary steps required for catalytic combustion of dimethyl ether (DME) on Pt clusters were determined by combining isotopic and kinetic analyses with density functional theory estimates of reaction energies and activation barriers to probe the lowest energy paths. Reaction rates are limited by C-H bond activation in DME molecules adsorbed on surfaces of Pt clusters containing chemisorbed oxygen atoms at near-saturation coverages. Reaction energies and activation barriers for C-H bond activation in DME to form methoxymethyl and hydroxyl surface intermediates show that this step is more favorable than the activation of C-O bonds to form two methoxides, consistent with measured rates and kinetic isotope effects. This kinetic preference is driven by the greater stability of the CH3OCH2* and OH* intermediates relative to chemisorbed methoxides. Experimental activation barriers on Pt clusters agree with density functional theory (DFT)-derived barriers on oxygen-covered Pt(111). Measured DME turnover rates increased with increasing DME pressure, but decreased as the O2 pressure increased, because vacancies (*) on Pt surfaces nearly saturated with chemisorbed oxygen are required for DME chemisorption. DFT calculations show that although these surface vacancies are required, higher oxygen coverages lead to lower C-H activation barriers, because the basicity of oxygen adatoms increases with coverage and they become more effective in hydrogen abstraction from DME. Water inhibits reaction rates via quasi-equilibrated adsorption on vacancy sites, consistent with DFT results indicating that water binds more strongly than DME on vacancies. These conclusions are consistent with the measured kinetic response of combustion rates to DME, O2, and H2O, with H/D kinetic isotope effects, and with the absence of isotopic scrambling in reactants containing isotopic mixtures of 18O2-16O2 or 12CH3O12CH3-13CH3O13CH3. Turnover rates increased with Pt cluster size, because small clusters, with more coordinatively unsaturated surface atoms, bind oxygen atoms more strongly than larger clusters and exhibit lower steady-state vacancy concentrations and a consequently smaller number of adsorbed DME intermediates involved in kinetically relevant steps. These effects of cluster size and metal-oxygen bond energies on reactivity are ubiquitous in oxidation reactions requiring vacancies on surfaces nearly saturated with intermediates derived from O2. PMID:17915866

Ishikawa, Akio; Neurock, Matthew; Iglesia, Enrique

2007-10-31

286

AKT/mTOR and c-Jun N-terminal kinase signaling pathways are required for chrysotile asbestos-induced autophagy.  

PubMed

Chrysotile asbestos is closely associated with excess mortality from pulmonary diseases such as lung cancer, mesothelioma, and asbestosis. Although multiple mechanisms in which chrysotile asbestos fibers induce pulmonary disease have been identified, the role of autophagy in human lung epithelial cells has not been examined. In this study, we evaluated whether chrysotile asbestos induces autophagy in A549 human lung epithelial cells and then analyzed the possible underlying molecular mechanism. Chrysotile asbestos induced autophagy in A549 cells based on a series of biochemical and microscopic autophagy markers. We observed that asbestos increased expression of A549 cell microtubule-associated protein 1 light chain 3 (LC3-II), an autophagy marker, in conjunction with dephosphorylation of phospho-AKT, phospho-mTOR, and phospho-p70S6K. Notably, AKT1/AKT2 double-knockout murine embryonic fibroblasts (MEFs) had negligible asbestos-induced LC3-II expression, supporting a crucial role for AKT signaling. Chrysotile asbestos also led to the phosphorylation/activation of Jun N-terminal kinase (JNK) and p38 MAPK. Pharmacologic inhibition of JNK, but not p38 MAPK, dramatically inhibited the protein expression of LC3-II. Moreover, JNK2(-/-) MEFs but not JNK1(-/-) MEFs blocked LC3-II levels induced by chrysotile asbestos. In addition, N-acetylcysteine, an antioxidant, attenuated chrysotile asbestos-induced dephosphorylation of P-AKT and completely abolished phosphorylation/activation of JNK. Finally, we demonstrated that chrysotile asbestos-induced apoptosis was not affected by the presence of the autophagy inhibitor 3-methyladenine or autophagy-related gene 5 siRNA, indicating that the chrysotile asbestos-induced autophagy may be adaptive rather than prosurvival. Our findings demonstrate that AKT/mTOR and JNK2 signaling pathways are required for chrysotile asbestos-induced autophagy. These data provide a mechanistic basis for possible future clinical applications targeting these signaling pathways in the management of asbestos-induced lung disease. PMID:24735948

Lin, Ziying; Liu, Tie; Kamp, David W; Wang, Yahong; He, Huijuan; Zhou, Xu; Li, Donghong; Yang, Lawei; Zhao, Bin; Liu, Gang

2014-07-01

287

Involvement of the janus kinase/signal transducer and activator of transcription signaling pathway in multiple sclerosis and the animal model of experimental autoimmune encephalomyelitis.  

PubMed

Multiple sclerosis (MS) and its animal model of experimental autoimmune encephalomyelitis (EAE) are characterized by focal inflammatory infiltrates into the central nervous system, demyelinating lesions, axonal damage, and abundant production of cytokines that activate immune cells and damage neurons and oligodendrocytes, including interleukin-12 (IL-12), IL-6, IL-17, IL-21, IL-23, granulocyte macrophage-colony stimulating factor, and interferon-gamma. The Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) signaling pathway mediates the biological activities of these cytokines and is essential for the development and regulation of immune responses. Dysregulation of the JAK/STAT pathway contributes to numerous autoimmune diseases, including MS/EAE. The JAK/STAT pathway is aberrantly activated in MS/EAE because of excessive production of cytokines, loss of expression of negative regulators such as suppressors of cytokine signaling proteins, and significant enrichment of genes encoding components of the JAK/STAT pathway, including STAT3. Specific JAK/STAT inhibitors have been used in numerous preclinical models of MS and demonstrate beneficial effects on the clinical course of disease and attenuation of innate and adaptive immune responses. In addition, other drugs such as statins, glatiramer acetate, laquinimod, and fumarates have beneficial effects that involve inhibition of the JAK/STAT pathway. We conclude by discussing the feasibility of the JAK/STAT pathway as a target for neuroinflammatory diseases. PMID:25084174

Benveniste, Etty N; Liu, Yudong; McFarland, Braden C; Qin, Hongwei

2014-08-01

288

Rigosertib as a selective anti-tumor agent can ameliorate multiple dysregulated signaling transduction pathways in high-grade myelodysplastic syndrome.  

PubMed

Rigosertib has demonstrated therapeutic activity for patients with high-risk myelodysplastic syndrome (MDS) in clinical trials. However, the role of rigosertib in MDS has not been thoroughly characterized. In this study, we found out that rigosertib induced apoptosis, blocked the cell cycle at the G2/M phase and subsequently inhibited the proliferation of CD34+ cells from MDS, while it minimally affected the normal CD34+ cells. Further studies showed that rigosertib acted via the activation of the P53 signaling pathway. Bioinformatics analysis based on gene expression profile and flow cytometry analysis revealed the abnormal activation of the Akt-PI3K, Jak-STAT and Wnt pathways in high-grade MDS, while the p38 MAPK, SAPK/JNK and P53 pathways were abnormally activated in low-grade MDS. Rigosertib could markedly inhibit the activation of the Akt-PI3K and Wnt pathways, whereas it activated the SAPK/JNK and P53 pathways in high-grade MDS. A receptor tyrosine kinase phosphorylation array demonstrated that rigosertib could increase the activation of RET and PDGFR-? while reducing the activation of Tie2 and VEGFR2 in MDS cells. Taken together, these data indicate that rigosertib is a selective and promising anti-tumor agent that could ameliorate multiple dysregulated signaling transduction pathways in high-grade MDS. PMID:25472472

Xu, Feng; He, Qi; Li, Xiao; Chang, Chun-Kang; Wu, Ling-Yun; Zhang, Zheng; Liu, Li; Shi, Wen-Hui; Zhu, Yang; Zhao, You-Shan; Gu, Shu-Cheng; Fei, Cheng-Ming; Guo, Juan; Wu, Dong; Zhou, Liyu

2014-01-01

289

Prostasin Is Required for Matriptase Activation in Intestinal Epithelial Cells to Regulate Closure of the Paracellular Pathway*  

PubMed Central

The type II transmembrane serine protease matriptase is a key regulator of epithelial barriers in skin and intestine. In skin, matriptase acts upstream of the glycosylphosphatidylinositol-anchored serine protease, prostasin, to activate the prostasin zymogen and initiate a proteolytic cascade that is required for stratum corneum barrier functionality. Here, we have investigated the relationship between prostasin and matriptase in intestinal epithelial barrier function. We find that similar to skin, matriptase and prostasin are components of a common intestinal epithelial barrier-forming pathway. Depletion of prostasin by siRNA silencing in Caco-2 intestinal epithelium inhibits barrier development similar to loss of matriptase, and the addition of recombinant prostasin to the basal side of polarized Caco-2 epithelium stimulates barrier forming changes similar to the addition of recombinant matriptase. However, in contrast to the proteolytic cascade in skin, prostasin functions upstream of matriptase to activate the endogenous matriptase zymogen. Prostasin is unable to proteolytically activate the matriptase zymogen directly but induces matriptase activation indirectly. Prostasin requires expression of endogenous matriptase to stimulate barrier formation since matriptase depletion by siRNA silencing abrogates prostasin barrier-forming activity. Active recombinant matriptase, however, does not require the expression of endogenous prostasin for barrier-forming activity. Together, these data show that matriptase and not prostasin is the primary effector protease of tight junction assembly in simple columnar epithelia and further highlight a spatial and tissue-specific aspect of cell surface proteolytic cascades. PMID:23443662

Buzza, Marguerite S.; Martin, Erik W.; Driesbaugh, Kathryn H.; Désilets, Antoine; Leduc, Richard; Antalis, Toni M.

2013-01-01

290

77 FR 12927 - Federal Acquisition Regulation: Requirements for Acquisitions Pursuant to Multiple-Award Contracts  

Federal Register 2010, 2011, 2012, 2013, 2014

...III; Docket 2011-0081, Sequence 1] RIN 9000-AL93 Federal...for Acquisitions Pursuant to Multiple-Award Contracts AGENCIES...all executive agencies under multiple-award contracts. DATES...award of orders placed under multiple-award contracts....

2012-03-02

291

p-21-Activated kinase 1 mediates gastrin-stimulated proliferation in the colorectal mucosa via multiple signaling pathways  

PubMed Central

Gastrins, including amidated (Gamide) and glycine-extended (Ggly) forms, function as growth factors for the gastrointestinal mucosa. The p-21-activated kinase 1 (PAK1) plays important roles in growth factor signaling networks that control cell motility, proliferation, differentiation, and transformation. PAK1, activated by both Gamide and Ggly, mediates gastrin-stimulated proliferation and migration, and activation of ?-catenin, in gastric epithelial cells. The aim of this study was to investigate the role of PAK1 in the regulation by gastrin of proliferation in the normal colorectal mucosa in vivo. Mucosal proliferation was measured in PAK1 knockout (PAK1 KO) mice by immunohistochemistry. The expression of phosphorylated and unphosphorylated forms of the signaling molecules PAK1, extracellular signal-regulated kinase (ERK), and protein kinase B (AKT), and the expression of ?-catenin and its downstream targets c-Myc and cyclin D1, were measured in gastrin knockout (Gas KO) and PAK1 KO mice by Western blotting. The expression and activation of PAK1 are decreased in Gas KO mice, and these decreases are associated with reduced activation of ERK, AKT, and ?-catenin. Proliferation in the colorectal mucosa of PAK1 KO mice is reduced, and the reduction is associated with reduced activation of ERK, AKT, and ?-catenin. In compensation, antral gastrin mRNA and serum gastrin concentrations are increased in PAK1 KO mice. These results indicate that PAK1 mediates the stimulation of colorectal proliferation by gastrins via multiple signaling pathways involving activation of ERK, AKT, and ?-catenin. PMID:23306081

Huynh, Nhi; Yim, Mildred; Chernoff, Jonathan; Shulkes, Arthur; Baldwin, Graham S.

2013-01-01

292

A melanin-independent interaction between Mc1r and Met signaling pathways is required for HGF-dependent melanoma.  

PubMed

Melanocortin 1 receptor (MC1R) signaling stimulates black eumelanin production through a cAMP-dependent pathway. MC1R polymorphisms can impair this process, resulting in a predominance of red phaeomelanin. The red hair, fair skin and UV sensitive phenotype is a well-described melanoma risk factor. MC1R polymorphisms also confer melanoma risk independent of pigment. We investigated the effect of Mc1r deficiency in a mouse model of UV-induced melanoma. C57BL/6-Mc1r+/+-HGF transgenic mice have a characteristic hyperpigmented black phenotype with extra-follicular dermal melanocytes located at the dermal/epidermal junction. UVB induces melanoma, independent of melanin pigmentation, but UVA-induced and spontaneous melanomas are dependent on black eumelanin. We crossed these mice with yellow C57BL/6-Mc1re/e animals which have a non-functional Mc1r and produce predominantly yellow phaeomelanin. Yellow C57BL/6-Mc1re/e-HGF mice produced no melanoma in response to UVR or spontaneously even though the HGF transgene and its receptor Met were expressed. Total melanin was less than in C57BL/6-Mc1r+/+-HGF mice, hyperpigmentation was not observed and there were few extra-follicular melanocytes. Thus, functional Mc1r was required for expression of the transgenic HGF phenotype. Heterozygous C57BL/6-Mc1re/+-HGF mice were black and hyperpigmented and, although extra-follicular melanocytes and skin melanin content were similar to C57BL/6-Mc1r+/+-HGF animals, they developed UV-induced and spontaneous melanomas with significantly less efficiency by all criteria. Thus, heterozygosity for Mc1r was sufficient to restore the transgenic HGF phenotype but insufficient to fully restore melanoma. We conclude that a previously unsuspected melanin-independent interaction between Mc1r and Met signaling pathways is required for HGF-dependent melanoma and postulate that this pathway is involved in human melanoma. PMID:24975581

Wolnicka-Glubisz, Agnieszka; Strickland, Faith M; Wielgus, Albert; Anver, Miriam; Merlino, Glenn; De Fabo, Edward C; Noonan, Frances P

2015-02-15

293

Rab3D Regulates a Novel Vesicular Trafficking Pathway That Is Required for Osteoclastic Bone Resorption†  

PubMed Central

Rab3 proteins are a subfamily of GTPases, known to mediate membrane transport in eukaryotic cells and play a role in exocytosis. Our data indicate that Rab3D is the major Rab3 species expressed in osteoclasts. To investigate the role of Rab3D in osteoclast physiology we examined the skeletal architecture of Rab3D-deficient mice and found an osteosclerotic phenotype. Although basal osteoclast number in null animals is normal the total eroded surface is significantly reduced, suggesting that the resorptive defect is due to attenuated osteoclast activity. Consistent with this hypothesis, ultrastructural analysis reveals that Rab3D?/? osteoclasts exhibit irregular ruffled borders. Furthermore, while overexpression of wild-type, constitutively active, or prenylation-deficient Rab3D has no significant effects, overexpression of GTP-binding-deficient Rab3D impairs bone resorption in vitro. Finally, subcellular localization studies reveal that, unlike wild-type or constitutively active Rab3D, which associate with a nonendosomal/lysosomal subset of post-trans-Golgi network (TGN) vesicles, inactive Rab3D localizes to the TGN and inhibits biogenesis of Rab3D-bearing vesicles. Collectively, our data suggest that Rab3D modulates a post-TGN trafficking step that is required for osteoclastic bone resorption. PMID:15923639

Pavlos, Nathan J.; Xu, Jiake; Riedel, Dietmar; Yeoh, Joyce S. G.; Teitelbaum, Steven L.; Papadimitriou, John M.; Jahn, Reinhard; Ross, F. Patrick; Zheng, Ming H.

2005-01-01

294

Multiplication  

NSDL National Science Digital Library

Which way of learning multiplication helped you the best? First you will need to use organizer Then you need to go to thinking blocks Next go to multiplication rap song Then go to dinosaur game and times table and lattice method and finally flashcards after this look over your graphic organizer and think about which site was most helpful for you. You will then be divided into groups where you will make your own creative lesson ...

Ms. Williams

2011-04-06

295

Optimization of photosynthesis by multiple metabolic pathways involving interorganelle interactions: resource sharing and ROS maintenance as the bases.  

PubMed

The bioenergetic processes of photosynthesis and respiration are mutually beneficial. Their interaction extends to photorespiration, which is linked to optimize photosynthesis. The interplay of these three pathways is facilitated by two major phenomena: sharing of energy/metabolite resources and maintenance of optimal levels of reactive oxygen species (ROS). The resource sharing among different compartments of plant cells is based on the production/utilization of reducing equivalents (NADPH, NADH) and ATP as well as on the metabolite exchange. The responsibility of generating the cellular requirements of ATP and NAD(P)H is mostly by the chloroplasts and mitochondria. In turn, besides the chloroplasts, the mitochondria, cytosol and peroxisomes are common sinks for reduced equivalents. Transporters located in membranes ensure the coordinated movement of metabolites across the cellular compartments. The present review emphasizes the beneficial interactions among photosynthesis, dark respiration and photorespiration, in relation to metabolism of C, N and S. Since the bioenergetic reactions tend to generate ROS, the cells modulate chloroplast and mitochondrial reactions, so as to ensure that the ROS levels do not rise to toxic levels. The patterns of minimization of ROS production and scavenging of excess ROS in intracellular compartments are highlighted. Some of the emerging developments are pointed out, such as model plants, orientation/movement of organelles and metabolomics. PMID:23881384

Sunil, Bobba; Talla, Sai K; Aswani, Vetcha; Raghavendra, Agepati S

2013-11-01

296

Cytokines, Signaling Pathways, and Effector Molecules Required for the Control of Leishmania (Viannia) braziliensis in Mice?  

PubMed Central

Cutaneous leishmaniasis is caused by protozoan parasites of the genus Leishmania. The mechanisms of pathogen control have been established primarily in the mouse model of Leishmania major infection, but they might not hold true for other Leishmania species associated with cutaneous disease. Here, we analyzed the role of cytokines, signaling components, and effector molecules in the control of New World cutaneous leishmaniasis due to L. braziliensis. Unlike L. major, L. braziliensis caused small, nonulcerative, and self-healing skin swelling in C57BL/6 mice, as well as BALB/c mice. In contrast to the results obtained for L. mexicana, mice deficient for interleukin-12 or its key signaling molecule, signal transducer and activator of transcription 4, rapidly succumbed to severe visceral leishmaniasis. Infection of tumor necrosis factor knockout mice with L. braziliensis led to progressive, nonhealing skin lesions with erosions and hemorrhagic ulcerations, but in contrast to the results with L. major, only 20 to 30% of the mice developed fatal visceral disease. As seen with L. major, mice with a deleted inducible nitric oxide synthase gene (iNOS?/?) were unable to contain L. braziliensis in the skin, whereas the control of the parasite in the spleen remained unimpaired. Unlike what happens in L. major infections, NADPH oxidase had no impact on the course of disease in L. braziliensis-infected mice. These results not only define essential components of a protective immune response to L. braziliensis but also illustrate that the requirements for the control of cutaneous leishmaniasis vary between different parasite species. PMID:17517868

Rocha, F. Janaina Soares; Schleicher, Ulrike; Mattner, Jochen; Alber, Gottfried; Bogdan, Christian

2007-01-01

297

Prophase pathway-dependent removal of cohesin from human chromosomes requires opening of the Smc3–Scc1 gate  

PubMed Central

Faithful transmission of chromosomes during eukaryotic cell division requires sister chromatids to be paired from their generation in S phase until their separation in M phase. Cohesion is mediated by the cohesin complex, whose Smc1, Smc3 and Scc1 subunits form a tripartite ring that entraps both DNA double strands. Whereas centromeric cohesin is removed in late metaphase by Scc1 cleavage, metazoan cohesin at chromosome arms is displaced already in prophase by proteolysis-independent signalling. Which of the three gates is triggered by the prophase pathway to open has remained enigmatic. Here, we show that displacement of human cohesin from early mitotic chromosomes requires dissociation of Smc3 from Scc1 but no opening of the other two gates. In contrast, loading of human cohesin onto chromatin in telophase occurs through the Smc1–Smc3 hinge. We propose that the use of differently regulated gates for loading and release facilitates unidirectionality of DNA's entry into and exit from the cohesin ring. PMID:23361318

Buheitel, Johannes; Stemmann, Olaf

2013-01-01

298

The Ess1 prolyl isomerase is required for transcription termination of small noncoding RNAs via the Nrd1 pathway.  

PubMed

Genome-wide studies have identified abundant small, noncoding RNAs, including small nuclear RNAs, small nucleolar RNAs (snoRNAs), cryptic unstable transcripts (CUTs), and upstream regulatory RNAs (uRNAs), that are transcribed by RNA polymerase II (pol II) and terminated by an Nrd1-dependent pathway. Here, we show that the prolyl isomerase Ess1 is required for Nrd1-dependent termination of noncoding RNAs. Ess1 binds the carboxy-terminal domain (CTD) of pol II and is thought to regulate transcription by conformational isomerization of Ser-Pro bonds within the CTD. In ess1 mutants, expression of approximately 10% of the genome was altered, due primarily to defects in termination of snoRNAs, CUTs, stable unannotated transcripts, and uRNAs. Ess1 promoted dephosphorylation of Ser5 (but not Ser2) within the CTD, most likely by the Ssu72 phosphatase. We also provide evidence for a competition between Nrd1 and Pcf11 for CTD binding that is regulated by Ess1. These data indicate that a prolyl isomerase is required for specifying the "CTD code." PMID:19854134

Singh, Navjot; Ma, Zhuo; Gemmill, Trent; Wu, Xiaoyun; Defiglio, Holland; Rossettini, Anne; Rabeler, Christina; Beane, Olivia; Morse, Randall H; Palumbo, Michael J; Hanes, Steven D

2009-10-23

299

Amyloid precursor protein is required for normal function of the rod and cone pathways in the mouse retina.  

PubMed

Amyloid precursor protein (APP) is a transmembrane glycoprotein frequently studied for its role in Alzheimer's disease. Our recent study in APP knockout (KO) mice identified an important role for APP in modulating normal neuronal development in the retina. However the role APP plays in the adult retina and whether it is required for vision is unknown. In this study we evaluated the role of APP in retinal function and morphology comparing adult wildtype (WT) and APP-KO mice. APP was expressed on neuronal cells of the inner retina, including horizontal, cone bipolar, amacrine and ganglion cells in WT mice. The function of the retina was assessed using the electroretinogram and although the rod photoreceptor responses were similar in APP-KO and WT mice, the post-photoreceptor, inner retinal responses of both the rod and cone pathways were reduced in APP-KO mice. These changes in inner retinal function did not translate to a substantial change in visual acuity as assessed using the optokinetic response or to changes in the gross cellular structure of the retina. These findings indicate that APP is not required for basic visual function, but that it is involved in modulating inner retinal circuitry. PMID:22279552

Ho, Tracy; Vessey, Kirstan A; Cappai, Roberto; Dinet, Virginie; Mascarelli, Frédéric; Ciccotosto, Giuseppe D; Fletcher, Erica L

2012-01-01

300

The TRIF-dependent signaling pathway is not required for acute cerebral ischemia/reperfusion injury in mice  

SciTech Connect

TIR domain-containing adaptor protein (TRIF) is an adaptor protein in Toll-like receptor (TLR) signaling pathways. Activation of TRIF leads to the activation of interferon regulatory factor 3 (IRF3) and nuclear factor kappa B (NF-{kappa}B). While studies have shown that TLRs are implicated in cerebral ischemia/reperfusion (I/R) injury and in neuroprotection against ischemia afforded by preconditioning, little is known about TRIF's role in the pathological process following cerebral I/R. The present study investigated the role that TRIF may play in acute cerebral I/R injury. In a mouse model of cerebral I/R induced by transient middle cerebral artery occlusion, we examined the activation of NF-{kappa}B and IRF3 signaling in ischemic cerebral tissue using ELISA and Western blots. Neurological function and cerebral infarct size were also evaluated 24 h after cerebral I/R. NF-{kappa}B activity and phosphorylation of the inhibitor of kappa B (I{kappa}B{alpha}) increased in ischemic brains, but IRF3, inhibitor of {kappa}B kinase complex-{epsilon} (IKK{epsilon}), and TANK-binding kinase1 (TBK1) were not activated after cerebral I/R in wild-type (WT) mice. Interestingly, TRIF deficit did not inhibit NF-{kappa}B activity or p-I{kappa}B{alpha} induced by cerebral I/R. Moreover, although cerebral I/R induced neurological and functional impairments and brain infarction in WT mice, the deficits were not improved and brain infarct size was not reduced in TRIF knockout mice compared to WT mice. Our results demonstrate that the TRIF-dependent signaling pathway is not required for the activation of NF-{kappa}B signaling and brain injury after acute cerebral I/R.

Hua, Fang, E-mail: fhua2@emory.edu [Department of Emergency Medicine, Brain Research Laboratory, Emory University School of Medicine, 1365B Clifton Road, Suite 5100, Atlanta, GA 30322 (United States)] [Department of Emergency Medicine, Brain Research Laboratory, Emory University School of Medicine, 1365B Clifton Road, Suite 5100, Atlanta, GA 30322 (United States); Wang, Jun; Sayeed, Iqbal; Ishrat, Tauheed; Atif, Fahim; Stein, Donald G. [Department of Emergency Medicine, Brain Research Laboratory, Emory University School of Medicine, 1365B Clifton Road, Suite 5100, Atlanta, GA 30322 (United States)] [Department of Emergency Medicine, Brain Research Laboratory, Emory University School of Medicine, 1365B Clifton Road, Suite 5100, Atlanta, GA 30322 (United States)

2009-12-18

301

Pseudomonas fluorescens: fur is required for multiple biological properties associated with pathogenesis.  

PubMed

Pseudomonas fluorescens, a Gram-negative bacterium, is an aquaculture pathogen with a broad host range. In a previous study, we had demonstrated that knockout of the fur gene of a pathogenic P. fluorescens strain, TSS, resulted in profound virulence attenuation. In this work, we studied the properties of the fur knockout mutant, TFM, in comparison with the wild type strain TSS. We found that compared to TSS, TFM (i) was impaired in siderophore production and extracellular enzyme activities, (ii) exhibited altered global polarity, (iii) was dramatically reduced in the ability to resist oxidative stress, (iv) showed higher tolerance to manganese, and (v) exhibited significantly reduced cytotoxicity. When incubated with cultured host cells, TFM displayed a cellular binding index much lower than that of TSS. Neither TFM nor TSS was able to survive and replicate in host cells. Following inoculation into Japanese flounder (Paralichthys olivaceus), TSS upregulated the expression of a wide range of genes involved in innate immunity, notably IL-1? and two CC chemokines. In contrast, TFM caused significant inductions of only a few genes and to much lower magnitudes than TSS. Given the strong inductions of IL-1? and the two chemokines by TSS, the effect of these three genes on P. fluorescens invasion was examined. The results showed that overexpression of these genes in flounder significantly inhibited TSS dissemination into and colonization of host tissues. Taken together, these results indicate that Fur is required for multiple processes associated with virulence, and that proinflammatory cytokines and chemokines likely play important roles in the clearance of P. fluorescens infection. PMID:25465175

Zhou, Ze-jun; Zhang, Lu; Sun, Li

2015-01-30

302

Characterization of multiple fragmentation pathways initiated by collision-induced dissociation of multifunctional anions formed by deprotonation of 2-nitrobenzenesulfonylglycine.  

PubMed

The correlation of anion structure with the fragmentation behavior of deprotonated nitrobenzenesulfonylamino acids was investigated using tandem mass spectrometry, isotopic labeling and computational methods. Four distinct fragmentation pathways resulting from the collision-induced dissociation (CID) of deprotonated 2-nitrobenzenesulfonylglycine (NsGly) were characterized. The unusual loss of the aryl nitro substituent as HONO was the lowest energy process. Subsequent successive losses of CO, HCN and SO2 indicated that an ortho cyclization reaction had accompanied loss of HONO. Other pathways involving rearrangement of the ionized sulfonamide group, dual bond cleavage and intramolecular nucleophilic displacement were proposed to account for the formation of phenoxide, arylsulfinate and arylsulfonamide product ions at higher collision energies. The four distinct fragmentation pathways were consistent with precursor-product relationships established by CID experiments, isotopic labeling results and the formation of analogous product ions from 2,4-dinitrobenzenesulfonylglycine and the Ns derivatives of alanine and 2-aminoisobutyric acid. The computations confirmed a low barrier for ortho cyclization with loss of HONO and feasible energetics for each reaction step in the four pathways. Computations also indicated that three of the fragmentation pathways started from NsGly ionized at the carboxyl group. Overall, the pathways identified for the fragmentation of the NsGly anion differed from processes reported for anions containing a single functional group, demonstrating the importance of functional group interactions in the fragmentation pathways of multifunctional anions. PMID:24677307

Tovstiga, Tara E; Gillis, Elizabeth A L; Grossert, J Stuart; White, Robert L

2014-02-01

303

Seeking unique and common biological themes in multiple gene lists or datasets: pathway pattern extraction pipeline for pathway-level comparative analysis  

Microsoft Academic Search

Background: One of the challenges in the analysis of microarray data is to integrate and compare the selected (e.g., differential) gene lists from multiple experiments for common or unique underlying biological themes. A common way to approach this problem is to extract common genes from these gene lists and then subject these genes to enrichment analysis to reveal the underlying

Ming Yi; Uma Mudunuri; Anney Che; Robert M. Stephens

2009-01-01

304

DEPTOR is an mTOR inhibitor frequently overexpressed in multiple myeloma cells and required for their survival.  

PubMed

The mTORC1 and mTORC2 pathways regulate cell growth, proliferation, and survival. We identify DEPTOR as an mTOR-interacting protein whose expression is negatively regulated by mTORC1 and mTORC2. Loss of DEPTOR activates S6K1, Akt, and SGK1, promotes cell growth and survival, and activates mTORC1 and mTORC2 kinase activities. DEPTOR overexpression suppresses S6K1 but, by relieving feedback inhibition from mTORC1 to PI3K signaling, activates Akt. Consistent with many human cancers having activated mTORC1 and mTORC2 pathways, DEPTOR expression is low in most cancers. Surprisingly, DEPTOR is highly overexpressed in a subset of multiple myelomas harboring cyclin D1/D3 or c-MAF/MAFB translocations. In these cells, high DEPTOR expression is necessary to maintain PI3K and Akt activation and a reduction in DEPTOR levels leads to apoptosis. Thus, we identify a novel mTOR-interacting protein whose deregulated overexpression in multiple myeloma cells represents a mechanism for activating PI3K/Akt signaling and promoting cell survival. PMID:19446321

Peterson, Timothy R; Laplante, Mathieu; Thoreen, Carson C; Sancak, Yasemin; Kang, Seong A; Kuehl, W Michael; Gray, Nathanael S; Sabatini, David M

2009-05-29

305

KeyPathwayMiner 4.0: condition-specific pathway analysis by combining multiple omics studies and networks with Cytoscape  

PubMed Central

Background Over the last decade network enrichment analysis has become popular in computational systems biology to elucidate aberrant network modules. Traditionally, these approaches focus on combining gene expression data with protein-protein interaction (PPI) networks. Nowadays, the so-called omics technologies allow for inclusion of many more data sets, e.g. protein phosphorylation or epigenetic modifications. This creates a need for analysis methods that can combine these various sources of data to obtain a systems-level view on aberrant biological networks. Results We present a new release of KeyPathwayMiner (version 4.0) that is not limited to analyses of single omics data sets, e.g. gene expression, but is able to directly combine several different omics data types. Version 4.0 can further integrate existing knowledge by adding a search bias towards sub-networks that contain (avoid) genes provided in a positive (negative) list. Finally the new release now also provides a set of novel visualization features and has been implemented as an app for the standard bioinformatics network analysis tool: Cytoscape. Conclusion With KeyPathwayMiner 4.0, we publish a Cytoscape app for multi-omics based sub-network extraction. It is available in Cytoscape’s app store http://apps.cytoscape.org/apps/keypathwayminer or via http://keypathwayminer.mpi-inf.mpg.de. PMID:25134827

2014-01-01

306

The role of adaptor protein Ste50-dependent regulation of the MAPKKK Ste11 in multiple signalling pathways of yeast  

Microsoft Academic Search

In Saccharomyces cerevisiae, Ste50 functions in cell signalling between the activated G protein and the mitogen-activated protein kinase (MAPK) kinase kinase (MAPKKK) Ste11. ScSte50 is an essential component of three MAPK-mediated signalling pathways, which control the mating response, invasive\\/filamentous growth and osmotolerance (HOG pathway), respectively. ScSte50 signalling may also contribute to cell wall integrity in vegetative cells. The protein contains

Massoud Ramezani-Rad

2003-01-01

307

Lipopolysaccharide-induced activation of NF-{kappa}B non-canonical pathway requires BCL10 serine 138 and NIK phosphorylations  

SciTech Connect

Background and aims: B-cell lymphoma/leukemia (BCL)-10 and reactive oxygen species mediate two pathways of NF-{kappa}B (RelA) activation by lipopolysaccharide (LPS) in human colonic epithelial cells. The pathway for LPS activation of RelB by the non-canonical pathway (RelB) in non-myeloid cells was not yet reported, but important for understanding the range of potential microbial LPS-induced effects in inflammatory bowel disease. Methods: Experiments were performed in human colonic epithelial cells and in mouse embryonic fibroblasts deficient in components of the IkappaB kinase (IKK) signalosome, in order to detect mediators of the non-canonical pathway of NF-{kappa}B activation, including nuclear RelB and p52 and phospho- and total NF-{kappa}B inducing kinase (NIK). BCL10 was silenced by siRNA and effects of mutations of specific phosphorylation sites of BCL10 (Ser138Gly and Ser218Gly) were determined. Results: By the non-canonical pathway, LPS exposure increased nuclear RelB and p52, and phospho-NIK, with no change in total NIK. Phosphorylation of BCL10 serine 138 was required for NIK phosphorylation, since mutation of this residue eliminated the increases in phospho-NIK and nuclear RelB and p52. Mutations of either serine 138 or serine 218 reduced RelA, p50, and phospho-I{kappa}B{alpha} of the canonical pathway. Effects of LPS stimulation and BCL10 silencing on NIK phosphorylation were demonstrated in confocal images. Conclusions: LPS induces activation of both canonical and non-canonical pathways of NF-{kappa}B in human colonic epithelial cells, and the non-canonical pathway requires phosphorylations of BCL10 (serine 138) and NIK. These findings demonstrate the important role of BCL10 in mediating LPS-induced inflammation in human colonic epithelial cells and may open new avenues for therapeutic interventions.

Bhattacharyya, Sumit; Borthakur, Alip; Dudeja, Pradeep K. [Department of Medicine, University of Illinois at Chicago and Jesse Brown VA Medical Center, Chicago, IL 60612-7227 (United States)] [Department of Medicine, University of Illinois at Chicago and Jesse Brown VA Medical Center, Chicago, IL 60612-7227 (United States); Tobacman, Joanne K., E-mail: jkt@uic.edu [Department of Medicine, University of Illinois at Chicago and Jesse Brown VA Medical Center, Chicago, IL 60612-7227 (United States)

2010-11-15

308

Delivery of endocytosed proteins to the cell–division plane requires change of pathway from recycling to secretion  

PubMed Central

Membrane trafficking is essential to fundamental processes in eukaryotic life, including cell growth and division. In plant cytokinesis, post-Golgi trafficking mediates a massive flow of vesicles that form the partitioning membrane but its regulation remains poorly understood. Here, we identify functionally redundant Arabidopsis ARF guanine-nucleotide exchange factors (ARF-GEFs) BIG1–BIG4 as regulators of post-Golgi trafficking, mediating late secretion from the trans-Golgi network but not recycling of endocytosed proteins to the plasma membrane, although the TGN also functions as an early endosome in plants. In contrast, BIG1-4 are absolutely required for trafficking of both endocytosed and newly synthesized proteins to the cell–division plane during cytokinesis, counteracting recycling to the plasma membrane. This change from recycling to secretory trafficking pathway mediated by ARF-GEFs confers specificity of cargo delivery to the division plane and might thus ensure that the partitioning membrane is completed on time in the absence of a cytokinesis-interphase checkpoint. DOI: http://dx.doi.org/10.7554/eLife.02131.001 PMID:24714496

Richter, Sandra; Kientz, Marika; Brumm, Sabine; Nielsen, Mads Eggert; Park, Misoon; Gavidia, Richard; Krause, Cornelia; Voss, Ute; Beckmann, Hauke; Mayer, Ulrike; Stierhof, York-Dieter; Jürgens, Gerd

2014-01-01

309

Neurospora crassa Female Development Requires the PACC and Other Signal Transduction Pathways, Transcription Factors, Chromatin Remodeling, Cell-To-Cell Fusion, and Autophagy  

PubMed Central

Using a screening protocol we have identified 68 genes that are required for female development in the filamentous fungus Neurospora crassa. We find that we can divide these genes into five general groups: 1) Genes encoding components of the PACC signal transduction pathway, 2) Other signal transduction pathway genes, including genes from the three N. crassa MAP kinase pathways, 3) Transcriptional factor genes, 4) Autophagy genes, and 5) Other miscellaneous genes. Complementation and RIP studies verified that these genes are needed for the formation of the female mating structure, the protoperithecium, and for the maturation of a fertilized protoperithecium into a perithecium. Perithecia grafting experiments demonstrate that the autophagy genes and the cell-to-cell fusion genes (the MAK-1 and MAK-2 pathway genes) are needed for the mobilization and movement of nutrients from an established vegetative hyphal network into the developing protoperithecium. Deletion mutants for the PACC pathway genes palA, palB, palC, palF, palH, and pacC were found to be defective in two aspects of female development. First, they were unable to initiate female development on synthetic crossing medium. However, they could form protoperithecia when grown on cellophane, on corn meal agar, or in response to the presence of nearby perithecia. Second, fertilized perithecia from PACC pathway mutants were unable to produce asci and complete female development. Protein localization experiments with a GFP-tagged PALA construct showed that PALA was localized in a peripheral punctate pattern, consistent with a signaling center associated with the ESCRT complex. The N. crassa PACC signal transduction pathway appears to be similar to the PacC/Rim101 pathway previously characterized in Aspergillus nidulans and Saccharomyces cerevisiae. In N. crassa the pathway plays a key role in regulating female development. PMID:25333968

Chinnici, Jennifer L.; Fu, Ci; Caccamise, Lauren M.; Arnold, Jason W.; Free, Stephen J.

2014-01-01

310

Fas activation of the p38 mitogen-activated protein kinase signalling pathway requires ICE/CED-3 family proteases.  

PubMed Central

The Fas receptor mediates a signalling cascade resulting in programmed cell death (apoptosis) within hours of receptor cross-linking. In this study Fas activated the stress-responsive mitogen-activated protein kinases, p38 and JNK, within 2 h in Jurkat T lymphocytes but not the mitogen-responsive kinase ERK1 or pp70S6k. Fas activation of p38 correlated temporally with the onset of apoptosis, and transfection of constitutively active MKK3 (glu), an upstream regulator of p38, potentiated Fas-induced cell death, suggesting a potential involvement of the MKK3/p38 activation pathway in Fas-mediated apoptosis. Fas has been shown to require ICE (interleukin-1 beta-converting enzyme) family proteases to induce apoptosis from studies utilizing the cowpox ICE inhibitor protein CrmA, the synthetic tetrapeptide ICE inhibitor YVAD-CMK, and the tripeptide pan-ICE inhibitor Z-VAD-FMK. In this study, crmA antagonized, and YVAD-CMK and Z-VAD-FMK completely inhibited, Fas activation of p38 kinase activity, demonstrating that Fas-dependent activation of p38 requires ICE/CED-3 family members and conversely that the MKK3/p38 activation cascade represents a downstream target for the ICE/CED-3 family proteases. Intriguingly, p38 activation by sorbitol and etoposide was resistant to YVAD-CMK and Z-VAD-FMK, suggesting the existence of an additional mechanism(s) of p38 regulation. The ICE/CED-3 family-p38 regulatory relationship described in the current work indicates that in addition to the previously described destructive cleavage of substrates such as poly(ADP ribose) polymerase, lamins, and topoisomerase, the apoptotic cysteine proteases also function to regulate stress kinase signalling cascades. PMID:8972182

Juo, P; Kuo, C J; Reynolds, S E; Konz, R F; Raingeaud, J; Davis, R J; Biemann, H P; Blenis, J

1997-01-01

311

Requirement of KISS1 Secretion for Multiple Organ Metastasis Suppression and Maintenance of Tumor Dormancy  

PubMed Central

Background The KISS1 protein suppresses metastasis of several tumor models without blocking orthotopic tumor growth, but the mechanism remains elusive. For its role in human sexual maturation, KISS1 protein is secreted and processed to kisspeptins, which bind to the G protein–coupled receptor GPR54. We tested the hypothesis that KISS1 secretion is required for metastasis suppression via GPR54. Methods KISS1 containing an internal FLAG epitope with (KFM) or without (KFM?SS) a signal sequence was transfected into C8161.9 human melanoma cells, which do not express endogenous KISS1. Whole-cell lysates and conditioned medium from C8161.9KFM and C8161.9KFM?SS cells were collected and analyzed for kiss-peptins by immunoprecipitation and enzyme-linked immunosorbent assay. GPR54 levels were measured using real-time reverse transcription–polymerase chain reaction. The ability of conditioned medium from C8161.9KFM and C8161.9KFM?SS cells to stimulate calcium mobilization in GPR54-expressing Chinese hamster ovary cells (CHO-G) and in C8161.9 cells was evaluated. Metastasis was monitored in athymic mice (groups of 10 per experiment) that were injected with C8161.9KFM or C8161.9KFM?SS cells labeled with enhanced green fluorescent protein. Survival of mice injected with C8161.9 or C8161.9KFM cells was analyzed by Kaplan–Meier methods. Results Full-length KFM and KFM SS were detected in whole-cell lysates of C8161.9KFM and C8161.9KFM?SS cells, respectively, but kisspeptins were detected only in conditioned medium of C8161.9KFM cells. In vivo, C8161.9KFM, but not C8161.9KFM?SS, cells were suppressed for metastasis to lung, eye, kidney, and bone, with corresponding differences in mouse survival (median > 120 versus 42 days). C8161.9KFM cells seeded mouse lungs but did not form macroscopic metastases. Conditioned medium from C8161.9KFM, but not C8161.9KFM?SS, cells stimulated calcium mobilization in CHO-G cells. GPR54 expression was low in C8161.9 cells, which were not stimulated by conditioned medium from C8161.9KFM cells. Conclusions KISS1 secretion was required for multiple organ metastasis suppression and for maintenance of disseminated cells in a dormant state. The absence of GPR54 expression in C8161.9 cells (whose metastatic spread was suppressed by KFM) suggests that metastasis suppression is not mediated through this receptor. The results imply the existence of another KISS1 receptor and/or paracrine signaling. The findings raise the possibility that soluble KISS1, kisspeptins, or mimetics could be used to maintain tumor dormancy, rendering treatment of already disseminated tumor cells (i.e., micrometastases) a legitimate target. PMID:17312308

Nash, Kevin T.; Phadke, Pushkar A.; Navenot, Jean-Marc; Hurst, Douglas R.; Accavitti-Loper, Mary Ann; Sztul, Elizabeth; Vaidya, Kedar S.; Frost, Andra R.; Kappes, John C.; Peiper, Stephen C.; Welch, Danny R.

2007-01-01

312

Morphological and Proteomic Analyses Reveal that Unsaturated Guluronate Oligosaccharide Modulates Multiple Functional Pathways in Murine Macrophage RAW264.7 Cells.  

PubMed

Alginate is a natural polysaccharide extracted from various species of marine brown algae. Alginate-derived guluronate oligosaccharide (GOS) obtained by enzymatic depolymerization has various pharmacological functions. Previous studies have demonstrated that GOS can trigger the production of inducible nitric oxide synthase (iNOS)/nitric oxide (NO), reactive oxygen species (ROS) and tumor necrosis factor (TNF)-? by macrophages and that it is involved in the nuclear factor (NF)-?B and mitogen-activated protein (MAP) kinase signaling pathways. To expand upon the current knowledge regarding the molecular mechanisms associated with the GOS-induced immune response in macrophages, comparative proteomic analysis was employed together with two-dimensional electrophoresis (2-DE), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) and Western blot verification. Proteins showing significant differences in expression in GOS-treated cells were categorized into multiple functional pathways, including the NF-?B signaling pathway and pathways involved in inflammation, antioxidant activity, glycolysis, cytoskeletal processes and translational elongation. Moreover, GOS-stimulated changes in the morphologies and actin cytoskeleton organization of RAW264.7 cells were also investigated as possible adaptations to GOS. This study is the first to reveal GOS as a promising agent that can modulate the proper balance between the pro- and anti-inflammatory immune responses, and it provides new insights into pharmaceutical applications of polysaccharides. PMID:25830683

Xu, Xu; Bi, De-Cheng; Li, Chao; Fang, Wei-Shan; Zhou, Rui; Li, Shui-Ming; Chi, Lian-Li; Wan, Min; Shen, Li-Ming

2015-01-01

313

Identification of a Calcineurin-Independent Pathway Required for Sodium Ion Stress Response inSaccharomyces cerevisiae  

Microsoft Academic Search

The calcium-dependent protein phosphatase calcineurin plays an essential role in ion homeostasis in yeast. In this study, we identify a parallel ion stress response pathway that is independent of the calcineurin signaling pathway. Cells with null alleles in both STD1 and its homologue, MTH1, manifest numerous phenotypes observed in calcineurin mutants, including sodium, lithium, manganese, and hydroxyl ion sensitivity, as

Raymond W. Ganster; Rhonda R. McCartney; Martin C. Schmidt

314

24 CFR 1710.15 - Regulatory exemption-multiple site subdivision-determination required.  

Code of Federal Regulations, 2010 CFR

...permits or other requirements for water, sewer and electrical installations...permits or other requirements for water, sewer and electrical installations...Governmental agency Supplier Water Sewer Electricity If...

2010-04-01

315

Multiple organellar RNA editing factor (MORF) family proteins are required for RNA editing in mitochondria and plastids of plants  

PubMed Central

RNA editing in plastids and mitochondria of flowering plants changes hundreds of selected cytidines to uridines, mostly in coding regions of mRNAs. Specific sequences around the editing sites are presumably recognized by up to 200 pentatricopeptide repeat (PPR) proteins. The here identified family of multiple organellar RNA editing factor (MORF) proteins provides additional components of the RNA editing machinery in both plant organelles. Two MORF proteins are required for editing in plastids; at least two are essential for editing in mitochondria. The loss of a MORF protein abolishes or lowers editing at multiple sites, many of which are addressed individually by PPR proteins. In plastids, both MORF proteins are required for complete editing at almost all sites, suggesting a heterodimeric complex. In yeast two-hybrid and pull-down assays, MORF proteins can connect to form hetero- and homodimers. Furthermore, MORF proteins interact selectively with PPR proteins, establishing a more complex editosome in plant organelles than previously thought. PMID:22411807

Takenaka, Mizuki; Zehrmann, Anja; Verbitskiy, Daniil; Kugelmann, Matthias; Härtel, Barbara; Brennicke, Axel

2012-01-01

316

The K-fgf/hst oncogene induces transformation through an autocrine mechanism that requires extracellular stimulation of the mitogenic pathway.  

PubMed Central

The K-fgf/hst oncogene encodes a secreted growth factor of the fibroblast growth factor (FGF) family. The ability of K-fgf-transformed cells to grow in soft agar and in serum-free medium is inhibited by anti-K-FGF neutralizing antibodies, consistent with an autocrine mechanism of transformation. The transformed properties of clones that express high levels of K-FGF are, however, only partially affected. To better define the autocrine mechanism of transformation by K-fgf and to determine whether receptor activation could occur intracellularly, we constructed two mutants of the K-fgf cDNA. Deletion of the sequences encoding the signal peptide suppressed K-fgf ability to induce foci in NIH 3T3 cells. A few morphologically transformed colonies were observed in cotransfection experiments, and they were found to express high levels of cytoplasmic K-FGF. However, their ability to grow in serum-free medium and in soft agar was inhibited by anti-K-FGF antibodies. Addition of a sequence encoding the KDEL endoplasmic reticulum and Golgi retention signal to the K-fgf cDNA led to accumulation of the growth factor in intracellular compartments. The ability of the KDEL mutant to induce foci in NIH 3T3 cells was much lower than that of the wild-type cDNA, and also in this case the transformed phenotype was reverted by anti-K-FGF antibodies. These and other findings indicate that the transformed phenotype of cells expressing a nonsecretory K-FGF is due to the extracellular activation of the receptor by the small amounts of growth factor that these cells still release. Thus, transformation by K-fgf appears to be due to an autocrine growth mechanisms that requires activation of the mitogenic pathway at the cell surface. Images PMID:1990270

Talarico, D; Basilico, C

1991-01-01

317

A functional autophagy pathway is required for rapamycin-induced degradation of the Sgs1 helicase in Saccharomyces cerevisiae.  

PubMed

In yeast Saccharomyces cerevisiae, the immunosuppressant rapamycin mimics starvation by inhibiting the kinase Tor1. We recently documented that this treatment triggers a rapid degradation of Sgs1, a helicase involved in several biological processes such as the prevention of genomic instability. Herein, we show that yeast strains deleted for genes ATG2, ATG9, and PEP4, encoding components of the autophagy pathway, prevent rapamycin-induced degradation of Sgs1. We propose that defects in the autophagy pathway prevent degradation of key proteins in the rapamycin response pathway and as a consequence cause resistance to the drug. PMID:23668784

Marrakchi, Rim; Chouchani, Chedly; Poschmann, Jeremie; Andreev, Emil; Cherif, Mohamed; Ramotar, Dindial

2013-06-01

318

Regenerator sites selection based on multiple paths considering impairments and protection requirements  

Microsoft Academic Search

We propose hitting set heuristic for regenerator sites selection considering multiple paths to provide any-to-any protected connectivity. The results indicate that parameters do not have impact for small networks for path trails greater than two. I. INTRODUCTION In translucent optical networks, optical signal will remain in the optical domain and will be regenerated only when its quality falls below a

Chava Vijaya Saradhi; Riccardo Fedrizzi; Andrea Zanardi; Elio Salvadori; Gabriele Maria Galimberti; Alberto Tanzi; Giovanni Martinelli; Ori Gerstel

2011-01-01

319

Mold sensitization is common amongst patients with severe asthma requiring multiple hospital admissions  

Microsoft Academic Search

BACKGROUND: Multiple studies have linked fungal exposure to asthma, but the link to severe asthma is controversial. We studied the relationship between asthma severity and immediate type hypersensitivity to mold (fungal) and non-mold allergens in 181 asthmatic subjects. METHODS: We recruited asthma patients aged 16 to 60 years at a University hospital and a nearby General Practice. Patients were categorized

B Ronan O'Driscoll; Linda C Hopkinson; David W Denning

2005-01-01

320

Abstract--Modern personal communication handsets are required to operate at multiple frequency bands for location  

E-print Network

communication. Standard Planar Inverted-F Antenna (PIFA) is a promising structure as a starting element to realize multiband antennas [4]. Multiple resonances in the antenna structure are excited by creating slots in the radiating element or resonating strips are judicially located in the antenna structure. Impedance matching

Park, Seong-Ook

321

From a Subtractive to Multiplicative Approach: A Concept-Driven Interactive Pathway on the Selective Absorption of Light  

ERIC Educational Resources Information Center

This research documents the aims and the impact of a teaching experiment on how the absorption of light depends on the thickness of the absorbing medium. This teaching experiment is more specifically characterized as bringing to bear a "concept-driven interactive pathway". It is designed to make students analyse the absorption of light…

Viennot, Laurence; de Hosson, Cécile

2015-01-01

322

Randomness requirement on the Clauser-Horne-Shimony-Holt Bell test in the multiple-run scenario  

NASA Astrophysics Data System (ADS)

The Clauser-Horne-Shimony-Holt inequality test is widely used as a means of invalidating the local deterministic theories and a tool of device-independent quantum cryptographic tasks. There exists a randomness (free will) loophole in the test, which is widely believed impossible to be closed perfectly, that is, certain random inputs are required for the test. Following a randomness quantification method used in literature, we investigate the randomness required in the test under various assumptions. By comparing the results, we conclude that, in order to make the test result reliable, it is more important to rule out the correlation between multiple runs than the correlation between two parties.

Yuan, Xiao; Cao, Zhu; Ma, Xiongfeng

2015-03-01

323

The alternative pathway is required, but not alone sufficient, for retinal pathology in mouse laser-induced choroidal neovascularization  

PubMed Central

Human genetic studies have demonstrated that polymorphisms in different complement proteins can increase the risk for developing AMD. There are three pathways of complement activation, classical (CP), alternative (AP), and lectin (LP), which all activate a final common pathway. Proteins encoded by the AMD risk genes participate in the AP (CFB), CP/LP (C2), or in the AP and final common pathway (C3). Here we tested which pathway is essential in mouse laser-induced CNV. CNV was analyzed using single complement pathway knockouts (i.e., eliminating one complement pathway at a time), followed by a double knockout in which only the AP is present, and the CP and LP are disabled, using molecular, histological and electrophysiological outcomes. First, single-gene knockouts were analyzed and compared to wild type mice; C1q?/? (no CP), MBL?/? (no LP), and CFB?/? (no AP). Six days after the laser-induced lesion, mice without a functional AP had reduced CNV progression (P<0.001) and preserved ERG amplitudes, whereas those without a functional CP or LP were indistinguishable from the wild type controls (P>0.3). Second, AP-only mice (C1q?/? MBL?/?) were as protected from developing CNV as the CFB?/? mice. The degree of pathology in each strain correlated with protein levels of the angiogenic and anti-angiogenic proteins VEGF and PEDF, respectively, as well as levels of terminal pathway activation product C5a, and C9. The analysis of complement activation pathways in mouse laser-induced CNV allows for the following conclusions. Comparing the single pathway knockouts with those having only a functional AP showed: (1) that AP activation is necessary, but not alone sufficient for injury; and (2) that initial complement activation proceeds via both the LP and CP. Thus, these data indicate an important role for the AP in the generation of complement-dependent injury in the RPE and choroid via amplification of CP- and LP-initiated complement activation. Improving our understanding of the local regulation of this pathway in the eye is essential for developing improved treatment approaches for AMD. PMID:21257205

Rohrer, Bärbel; Coughlin, Beth; Kunchithapautham, Kannan; Long, Qin; Tomlinson, Stephen; Takahashi, Kazue; Holers, V. Michael

2011-01-01

324

The novel histone deacetylase inhibitor, AR-42, inhibits gp130/Stat3 pathway and induces apoptosis and cell cycle arrest in multiple myeloma cells  

PubMed Central

Multiple myeloma (MM) remains incurable with current therapy, indicating the need for continued development of novel therapeutic agents. We evaluated the activity of a novel phenylbutyrate-derived histone deacetylase inhibitor, AR-42, in primary human myeloma cells and cell lines. AR-42 was cytotoxic to MM cells at a mean LC50 of 0.18 ± 0.06 ?mol/l at 48 hr and induced apoptosis with cleavage of caspases 8, 9 and 3, with cell death largely prevented by caspase inhibition. AR-42 downregulated the expression of gp130 and inhibited activation of STAT3, with minimal effects on the PI3K/Akt and MAPK pathways, indicating a predominant effect on the gp130/STAT-3 pathway. AR-42 also inhibited interleukin (IL)-6-induced STAT3 activation, which could not be overcome by exogenous IL-6. AR-42 also downregulated the expression of STAT3-regulated targets, including Bcl-xL and cyclin D1. Overexpression of Bcl-xL by a lentivirus construct partly protected against cell death induced by AR-42. The cyclin dependent kinase inhibitors, p16 and p21, were also significantly induced by AR-42, which together with a decrease in cyclin D1, resulted in G1 and G2 cell cycle arrest. In conclusion, AR-42 has potent cytotoxicity against MM cells mainly through gp130/STAT-3 pathway. The results provide rationale for clinical investigation of AR-42 in MM. PMID:20824695

Zhang, Shuhong; Suvannasankha, Attaya; Crean, Colin D.; White, Valerie L.; Chen, Ching-Shih; Farag, Sherif S.

2014-01-01

325

Phyllanthus Suppresses Prostate Cancer Cell, PC-3, Proliferation and Induces Apoptosis through Multiple Signalling Pathways (MAPKs, PI3K/Akt, NF?B, and Hypoxia)  

PubMed Central

Phyllanthus is a traditional medicinal plant that has been found to have antihepatitis, antibacterial, and anticancer properties. The present studies were to investigate the in vitro molecular mechanisms of anticancer effects of Phyllanthus (P. amarus, P. niruri, P. urinaria, and P. watsonii) plant extracts in human prostate adenocarcinoma. The cancer ten-pathway reporter array was performed and revealed that the expression of six pathway reporters were significantly decreased (Wnt, NF?B, Myc/Max, hypoxia, MAPK/ERK, and MAPK/JNK) in PC-3 cells after treatment with Phyllanthus extracts. Western blot was conducted and identified several signalling molecules that were affected in the signalling pathways including pan-Ras, c-Raf, RSK, Elk1, c-Jun, JNK1/2, p38 MAPK, c-myc, DSH, ?-catenin, Akt, HIF-1?, GSK3?, NF?B p50 and p52, Bcl-2, Bax, and VEGF, in treated PC-3 cells. A proteomics-based approach, 2D gel electrophoresis, was performed, and mass spectrometry (MS/MS) results revealed that there were 72 differentially expressed proteins identified in treated PC-3 cells and were involved in tumour cell adhesion, apoptosis, glycogenesis and glycolysis, metastasis, angiogenesis, and protein synthesis and energy metabolism. Overall, these findings suggest that Phyllanthus can interfere with multiple signalling cascades involved in tumorigenesis and be used as a potential therapeutic candidate for treatment of cancer. PMID:23690850

Tang, Yin-Quan; Jaganath, InduBala; Manikam, Rishya

2013-01-01

326

Phyllanthus Suppresses Prostate Cancer Cell, PC-3, Proliferation and Induces Apoptosis through Multiple Signalling Pathways (MAPKs, PI3K/Akt, NF?B, and Hypoxia).  

PubMed

Phyllanthus is a traditional medicinal plant that has been found to have antihepatitis, antibacterial, and anticancer properties. The present studies were to investigate the in vitro molecular mechanisms of anticancer effects of Phyllanthus (P. amarus, P. niruri, P. urinaria, and P. watsonii) plant extracts in human prostate adenocarcinoma. The cancer ten-pathway reporter array was performed and revealed that the expression of six pathway reporters were significantly decreased (Wnt, NF?B, Myc/Max, hypoxia, MAPK/ERK, and MAPK/JNK) in PC-3 cells after treatment with Phyllanthus extracts. Western blot was conducted and identified several signalling molecules that were affected in the signalling pathways including pan-Ras, c-Raf, RSK, Elk1, c-Jun, JNK1/2, p38 MAPK, c-myc, DSH, ?-catenin, Akt, HIF-1?, GSK3?, NF?B p50 and p52, Bcl-2, Bax, and VEGF, in treated PC-3 cells. A proteomics-based approach, 2D gel electrophoresis, was performed, and mass spectrometry (MS/MS) results revealed that there were 72 differentially expressed proteins identified in treated PC-3 cells and were involved in tumour cell adhesion, apoptosis, glycogenesis and glycolysis, metastasis, angiogenesis, and protein synthesis and energy metabolism. Overall, these findings suggest that Phyllanthus can interfere with multiple signalling cascades involved in tumorigenesis and be used as a potential therapeutic candidate for treatment of cancer. PMID:23690850

Tang, Yin-Quan; Jaganath, Indubala; Manikam, Rishya; Sekaran, Shamala Devi

2013-01-01

327

Pituitary adenylate cyclase-activating polypeptide (PACAP) inhibits the slow afterhyperpolarizing current sIAHP in CA1 pyramidal neurons by activating multiple signaling pathways  

PubMed Central

The slow afterhyperpolarizing current (sIAHP) is a calcium-dependent potassium current that underlies the late phase of spike frequency adaptation in hippocampal and neocortical neurons. sIAHP is a well-known target of modulation by several neurotransmitters acting via the cyclic AMP (cAMP) and protein kinase A (PKA)-dependent pathway. The neuropeptide pituitary adenylate cyclase activating peptide (PACAP) and its receptors are present in the hippocampal formation. In this study we have investigated the effect of PACAP on the sIAHP and the signal transduction pathway used to modulate intrinsic excitability of hippocampal pyramidal neurons. We show that PACAP inhibits the sIAHP, resulting in a decrease of spike frequency adaptation, in rat CA1 pyramidal cells. The suppression of sIAHP by PACAP is mediated by PAC1 and VPAC1 receptors. Inhibition of PKA reduced the effect of PACAP on sIAHP, suggesting that PACAP exerts part of its inhibitory effect on sIAHP by increasing cAMP and activating PKA. The suppression of sIAHP by PACAP was also strongly hindered by the inhibition of p38 MAP kinase (p38 MAPK). Concomitant inhibition of PKA and p38 MAPK indicates that these two kinases act in a sequential manner in the same pathway leading to the suppression of sIAHP. Conversely, protein kinase C is not part of the signal transduction pathway used by PACAP to inhibit sIAHP in CA1 neurons. Our results show that PACAP enhances the excitability of CA1 pyramidal neurons by inhibiting the sIAHP through the activation of multiple signaling pathways, most prominently cAMP/PKA and p38 MAPK. Our findings disclose a novel modulatory action of p38 MAPK on intrinsic excitability and the sIAHP, underscoring the role of this current as a neuromodulatory hub regulated by multiple protein kinases in cortical neurons. © 2013 The Authors. Hippocampus Published by Wiley Periodicals, Inc. PMID:23996525

Taylor, Ruth DT; Madsen, Marita Grønning; Krause, Michael; Sampedro-Castañeda, Marisol; Stocker, Martin; Pedarzani, Paola

2014-01-01

328

Synthetic promoters consisting of defined cis-acting elements link multiple signaling pathways to probenazole-inducible system.  

PubMed

Probenazole (3-allyloxy-1,2-benzisothiazole-1,1-dioxide, PBZ), the active component of Oryzemate, could induce systemic acquired resistance (SAR) in plants through the induction of salicylic acid (SA) biosynthesis. As a widely used chemical inducer, PBZ is a good prospect for establishing a new chemical-inducible system. We first designed artificially synthetic promoters with tandem copies of a single type of cis-element (SARE, JERE, GCC, GST1, HSRE, and W-box) that could mediate the expression of the ?-glucuronidase (GUS) reporter gene in plants upon PBZ treatment. Then we combined different types of elements in order to improve inducibility in the PBZ-inducible system. On the other hand, we were surprised to find that the cis-elements, which are responsive to jasmonic acid (JA) and ethylene, also responded to PBZ, implying that SA, JA, and ethylene pathways also would play important roles in PBZ's action. Further analysis demonstrated that PBZ also induced early events of innate immunity via a signaling pathway in which Ca(2+) influx and mitogen-activated protein kinase (MAPK) activity were involved. We constructed synthesized artificial promoters to establish a PBZ chemical-inducible system, and preliminarily explored SA, JA, ethylene, calcium, and MAPK signaling pathways via PBZ-inducible system, which could provide an insight for in-depth study. PMID:25845359

Zhu, Zheng; Gao, Jiong; Yang, Jin-Xiao; Wang, Xiao-Yan; Ren, Guo-Dong; Ding, Yu-Long; Kuai, Ben-Ke

2015-04-01

329

Synthetic promoters consisting of defined cis-acting elements link multiple signaling pathways to probenazole-inducible system * #  

PubMed Central

Probenazole (3-allyloxy-1,2-benzisothiazole-1,1-dioxide, PBZ), the active component of Oryzemate, could induce systemic acquired resistance (SAR) in plants through the induction of salicylic acid (SA) biosynthesis. As a widely used chemical inducer, PBZ is a good prospect for establishing a new chemical-inducible system. We first designed artificially synthetic promoters with tandem copies of a single type of cis-element (SARE, JERE, GCC, GST1, HSRE, and W-box) that could mediate the expression of the ?-glucuronidase (GUS) reporter gene in plants upon PBZ treatment. Then we combined different types of elements in order to improve inducibility in the PBZ-inducible system. On the other hand, we were surprised to find that the cis-elements, which are responsive to jasmonic acid (JA) and ethylene, also responded to PBZ, implying that SA, JA, and ethylene pathways also would play important roles in PBZ’s action. Further analysis demonstrated that PBZ also induced early events of innate immunity via a signaling pathway in which Ca2+ influx and mitogen-activated protein kinase (MAPK) activity were involved. We constructed synthesized artificial promoters to establish a PBZ chemical-inducible system, and preliminarily explored SA, JA, ethylene, calcium, and MAPK signaling pathways via PBZ-inducible system, which could provide an insight for in-depth study. PMID:25845359

Zhu, Zheng; Gao, Jiong; Yang, Jin-xiao; Wang, Xiao-yan; Ren, Guo-dong; Ding, Yu-long; Kuai, Ben-ke

2015-01-01

330

ERK and ?-Arrestin Interaction: A Converging Point of Signaling Pathways for Multiple Types of Cell Surface Receptors.  

PubMed

?-Arrestin, a signal adaptor protein, mediates intracellular signal transductions through protein-protein interactions by bringing two or more proteins in proximity. Extracellular signal-regulated kinase (ERK), a protein kinase in the family of mitogen-activated protein kinases (MAPKs), is involved in various receptor signal pathways. Interaction of ERK with ?-arrestin or formation of ERK/?-arrestin signal complex occurs in response to activation of a variety of cell surface receptors. The ERK/?-arrestin signal complex may be a common transducer to converge a variety of extracellular stimuli to similar downstream intracellular signaling pathways. By using a cell-based protein-protein interaction LinkLight assay technology, we demonstrate a direct interaction between ERK and ?-arrestin in response to extracellular stimuli, which can be sensitively and quantitatively monitored. Activations of G protein-coupled receptors (GPCRs), receptor tyrosine kinases (RTKs), and cytokine receptors promote formation of the ERK/?-arrestin signal complex. Our data indicate that the ERK/?-arrestin signal complex is a common transducer that participates in a variety of receptor signaling pathways. Furthermore, we demonstrate that receptor antagonists or kinase inhibitors can block the agonist-induced ERK and ?-arrestin interaction. Thus, the ERK/?-arrestin interaction assay is useful for screening of new receptor modulators. PMID:25361946

Eishingdrelo, Haifeng; Sun, Wei; Li, Hua; Wang, Li; Eishingdrelo, Alex; Dai, Sheng; McKew, John C; Zheng, Wei

2015-03-01

331

Risk Factors for Onset of Eating Disorders: Evidence of Multiple Risk Pathways from an 8-Year Prospective Study  

PubMed Central

Objective Use classification tree analysis with lagged predictors to determine empirically derived cut-points for identifying adolescent girls at risk for future onset of threshold, subthreshold, and partial eating disorders and test for interactions between risk factors that may implicate qualitatively distinct risk pathways. Method Data were drawn from a prospective study of 496 adolescent girls who completed diagnostic interviews and surveys annually for 8 years. Results Body dissatisfaction emerged as the most potent predictor; adolescent girls in the upper 24% of body dissatisfaction showed a 4.0-fold increased incidence of eating disorder onset (24% vs. 6%). Among participants in the high body dissatisfaction branch, those in the upper 32% of depressive symptoms showed a 2.9-fold increased incidence of onset (43% vs. 15%). Among participants in the low body dissatisfaction branch, those in the upper 12% of dieting showed a 3.6-fold increased incidence onset (18% vs. 5%). Conclusion This three-way interaction suggests a body dissatisfaction pathway to eating disorder onset that is amplified by depressive symptoms, as well as a pathway characterized by self-reported dieting among young women who are more satisfied with their bodies. It may be possible to increase the effectiveness of prevention programs by targeting each of these qualitatively distinct risk groups, rather than only individuals with a single risk factor. PMID:21764035

Stice, Eric; Marti, C. Nathan; Durant, Shelley

2014-01-01

332

Multiple Wnt genes are required for posterior patterning in the short germ embryo of Tribolium castaneum  

PubMed Central

Summary wingless (wg)/Wnt family genes encode secreted glycoproteins essential for the development of virtually all metazoans. In short germ insects, including the red flour beetle, Tribolium castaneum, the segment-polarity function of wg is conserved [1]. Wnt signalling is also implicated in posterior patterning and germband elongation [2–4], but despite its expression in the posterior growth zone, Wnt1/wg alone is not responsible for these functions; [1–3]. Tribolium contains additional Wnt family genes of unknown function that are also expressed in the growth zone [5]. After depleting one of these, Tc-WntD/8, we found a small percentage of embryos lacking abdominal segments. Additional removal of Tc-Wnt1 significantly enhanced this phenotype, suggesting functional redundancy. Seeking alternative methods to deplete Wnt signal, we performed RNAi with other components of the Wnt pathway including wntless (wls) and porcupine (porc), which process Wnt ligands, and pangolin (pan), which transduces the signal to the nucleus. Tc-wls RNAi caused segmentation defects similar to Tc-Wnt1, but not Tc-WntD/8 RNAi, indicating that the effects of Tc-WntD/8 depletion are Tc-wls-independent. In contrast, depletion of Tc-porc and Tc-pan resulted in embryos resembling those of double Tc-Wnt1,Tc-WntD/8 RNAi, suggesting Tc-porc is essential for the function of both ligands and that they signal through the canonical pathway. Our results provide the first evidence of functional redundancy between Wnt ligands in posterior patterning in short germ insects. This Wnt function appears to be conserved in other arthropods [6] and vertebrates [7–9]. PMID:18926702

Bolognesi, Renata; Farzana, Laila; Fischer, Tamara D.; Brown, Susan J.

2008-01-01

333

IRE-1/XBP-1 pathway of the unfolded protein response is required for properly localizing neuronal UNC-6/Netrin for axon guidance in C. elegans.  

PubMed

During developing nervous system, neurons project axons to their targets precisely. In this process, axon guidance molecules provide positional information to the axons. Therefore, the spatially and temporally controlled localization of the axon guidance molecules is required for the proper structure formation of the complex nervous system. In C. elegans, UNC-6/Netrin is a secreted protein that elicits both attractive and repulsive response in axon guidance. UNC-6/Netrin secreted from ventral cells may establish a concentration gradient from the ventral to the dorsal side of the animal, thus providing dorso-ventral positional information. However, the mechanisms specifying positional information of UNC-6/Netrin are largely unknown. Here, we show that the ire-1/xbp-1 pathway of the unfolded protein response (UPR) is required for axonal distribution of UNC-6/Netrin in the ventral neurons. In addition, the ire-1/xbp-1 pathway is also required for dorso-ventral axon guidance mediated by UNC-6/Netrin. Our results suggest that the ire-1/xbp-1 pathway of the UPR is crucial for establishing positional information of UNC-6/Netrin. We propose that the proper secretion of UNC-6/Netrin from the ventral neurons requires the activity of IRE-1. PMID:25469499

Asakura, Taro; Ogura, Ken-Ichi; Goshima, Yoshio

2015-03-01

334

Endosomal-sorting complexes required for transport (ESCRT) pathway-dependent endosomal traffic regulates the localization of active Src at focal adhesions  

PubMed Central

Active Src localization at focal adhesions (FAs) is essential for cell migration. How this pool is linked mechanistically to the large pool of Src at late endosomes (LEs)/lysosomes (LY) is not well understood. Here, we used inducible Tsg101 gene deletion, TSG101 knockdown, and dominant-negative VPS4 expression to demonstrate that the localization of activated cellular Src and viral Src at FAs requires the endosomal-sorting complexes required for transport (ESCRT) pathway. Tsg101 deletion also led to impaired Src-dependent activation of STAT3 and focal adhesion kinase and reduced cell migration. Impairment of the ESCRT pathway or Rab7 function led to the accumulation of active Src at aberrant LE/LY compartments followed by its loss. Analyses using fluorescence recovery after photo-bleaching show that dynamic mobility of Src in endosomes is ESCRT pathway-dependent. These results reveal a critical role for an ESCRT pathway-dependent LE/LY trafficking step in Src function by promoting localization of active Src to FAs. PMID:20805499

Tu, Chun; Ortega-Cava, Cesar F.; Winograd, Paul; Stanton, Marissa Jo; Reddi, Alagarsamy Lakku; Dodge, Ingrid; Arya, Ranjana; Dimri, Manjari; Clubb, Robert J.; Naramura, Mayumi; Wagner, Kay-Uwe; Band, Vimla; Band, Hamid

2010-01-01

335

Extracellular Signal-Regulated Kinase 1/2 Signaling Pathway Is Required for Endometrial Decidualization in Mice and Human  

PubMed Central

Decidualization is a crucial change required for successful embryo implantation and the maintenance of pregnancy. During this process, endometrial stromal cells differentiate into decidual cells in response to the ovarian steroid hormones of early pregnancy. Extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) are known to regulate cell proliferation and apoptosis in multiple cell types, including uterine endometrial cells. Aberrant activation of ERK1/2 has recently been implicated in the pathological processes of endometriosis and endometrial cancer. However, the function of ERK1/2 signaling during implantation and decidualization is still unknown. To determine the role and regulation of ERK1/2 signaling during implantation and decidualization, we examine ERK1/2 signaling in the mouse uterus during early pregnancy using immunostaining and qPCR. Interestingly, levels of phospho-ERK1/2 were highest within decidual cells located at the implantation sites. Expression levels of ERK1/2 target genes were also significantly higher at implantation sites, when compared to either inter-implantation sites. To determine if ERK1/2 signaling is also important during human endometrial decidualization, we examined levels of phospho-ERK1/2 in cultured human endometrial stromal cells during in vitro decidualization. Following treatment with a well-established decidualization-inducing steroidogenic cocktail, levels of phospho-ERK1/2 were markedly increased. Treatment with the ERK1/2 inhibitor, U0126, significantly decreased the expression of the known decidualization marker genes, IGFBP1 and PRL as well as inhibited the induction of known ERK1/2 target genes; FOS, MSK1, STAT1, and STAT3. Interestingly, the phosphorylation level of CCAAT/ enhancer binding protein ? (C/EBP?), a protein previously shown to be critical for decidualization, was significantly reduced in this model. These results suggest that ERK1/2 signaling is required for successful decidualization in mice as well as human endometrial stromal cells and implicates C/EBP? as a downstream target of ERK1/2. PMID:24086495

Lee, Chae Hyun; Kim, Tae Hoon; Lee, Jae Hee; Oh, Seo Jin; Yoo, Jung-Yoon; Kwon, Hyo Suk; Kim, Young Im; Ferguson, Susan D.; Ahn, Ji Yeon; Ku, Bon Jeong; Fazleabas, Asgerally T.; Lim, Jeong Mook; Jeong, Jae-Wook

2013-01-01

336

A Drosophila orthologue of larp protein family is required for multiple processes in male meiosis.  

PubMed

It is important for the proper execution of cell division in both mitosis and meiosis that the chromosome segregation, cytokinesis, and partition of cell organelles progress in smooth coordination. We show here that the mitochondria inheritance is closely linked with microtubules during meiotic divisions in Drosophila males. They are first clustered in a cell equator at metaphase associated with astral microtubules and then distributed along central spindle microtubules after anaphase. The molecular mechanism for the microtubule-dependent inheritance of mitochondria in male meiosis has not been demonstrated yet. We first isolated mutations for a larp gene that is highly conserved among eukaryotes and showed that these mutant males exhibited multiple meiotic phenotypes such as a failure of chromosome segregation, cytokinesis, and mitochondrial partition. Our cytological examination revealed that the mutants showed defects in spindle pole organization and spindle formation. The larp encodes a Drosophila orthologue of a La-related protein containing a domain exhibiting an outstanding homology with a La type RNA-binding protein. Surprisingly, the dLarp protein is localized in the cytoplasm of the male germ line cells, as observed by its distinct co-localization with mitochondria in early spermatocytes and during meiotic divisions. We discuss here the essential role that dLarp plays in multiple processes in Drosophila male meiosis. PMID:17951964

Ichihara, Keiko; Shimizu, Hanako; Taguchi, Osamu; Yamaguchi, Masamitsu; Inoue, Yoshihiro H

2007-01-01

337

miR-185 Plays an Anti-Hypertrophic Role in the Heart via Multiple Targets in the Calcium-Signaling Pathways  

PubMed Central

MicroRNA (miRNA) is an endogenous non-coding RNA species that either inhibits RNA translation or promotes degradation of target mRNAs. miRNAs often regulate cellular signaling by targeting multiple genes within the pathways. In the present study, using Gene Set Analysis, a useful bioinformatics tool to identify miRNAs with multiple target genes in the same pathways, we identified miR-185 as a key candidate regulator of cardiac hypertrophy. Using a mouse model, we found that miR-185 was significantly down-regulated in myocardial cells during cardiac hypertrophy induced by transverse aortic constriction. To confirm that miR-185 is an anti-hypertrophic miRNA, genetic manipulation studies such as overexpression and knock-down of miR-185 in neonatal rat ventricular myocytes were conducted. The results showed that up-regulation of miR-185 led to anti-hypertrophic effects, while down-regulation led to pro-hypertrophic effects, suggesting that miR-185 has an anti-hypertrophic role in the heart. Our study further identified Camk2d, Ncx1, and Nfatc3 as direct targets of miR-185. The activity of Nuclear Factor of Activated T-cell (NFAT) and calcium/calmodulin-dependent protein kinase II delta (CaMKII?) was negatively regulated by miR-185 as assessed by NFAT-luciferase activity and western blotting. The expression of phospho-phospholamban (Thr-17), a marker of CaMKII? activity, was also significantly reduced by miR-185. In conclusion, miR-185 effectively blocked cardiac hypertrophy signaling through multiple targets, rendering it a potential drug target for diseases such as heart failure. PMID:25767890

Kim, Jin Ock; Song, Dong Woo; Kwon, Eun Jeong; Hong, Seong-Eui; Song, Hong Ki; Min, Choon Kee; Kim, Do Han

2015-01-01

338

Glycosylation of IgA is required for optimal activation of the alternative complement pathway by immune complexes.  

PubMed Central

To investigate the effect of carbohydrate on activation of the alternative pathway of complement by IgA immune complexes, aglycosylated monoclonal IgA was made biosynthetically in the presence of tunicamycin. When immune complexes were incubated with normal human serum (NHS), the aglycosylated IgA immune complexes caused less depletion of the alternative pathway activity of the serum. They also bound less C3 and produced less terminal complement complexes. The binding of C3 to both immune complexes was mainly through hydroxylamine sensitive ester bonds. C3 did not bind to free IgA. Images Figure 1 Figure 5 Figure 6 PMID:8132210

Zhang, W; Lachmann, P J

1994-01-01

339

Primary involvement of the motor area in association with the nigrostriatal pathway in multiple system atrophy: neuropathological and morphometric evaluations  

Microsoft Academic Search

To evaluate the changes that occur in the motor and supplementary motor cortices in cases of multiple system atrophy (MSA), we carried out morphological and morphometric studies in 7 cases of MSA and 11 age-matched controls. Neuropathological study revealed presence of glial cytoplasmic inclusions (GCIs) in the cortex and subcortical white matter of the motor and supplementary motor areas, loss

Mu Su; Yasuji Yoshida; Yutaka Hirata; Yasuhito Watahiki; Ken Nagata

2001-01-01

340

pH-Jump-Induced Folding and Unfolding Studies of Barstar: Evidence for Multiple Folding and Unfolding Pathways  

E-print Network

pH-Jump-Induced Folding and Unfolding Studies of Barstar: Evidence for Multiple FoldingVised Manuscript ReceiVed September 26, 2001 ABSTRACT: Equilibrium and kinetic characterization of the high pH-induced unfolding transition of the small protein barstar have been carried out in the pH range 7-12. A mutant form

341

Vegetables’ juice influences polyol pathway by multiple mechanisms in favour of reducing development of oxidative stress and resultant diabetic complications  

PubMed Central

Objective: Hyperglycemia induced generation of free radicals and consequent development of oxidative stress by polyol pathway is one of the crucial mechanisms stirring up development of diabetic complications. We evaluated influence of ten vegetables’ juice on polyol pathway along with their antioxidant and antioxidative stress potentials. Materials and Methods: Aldose reductase activity was determined utilising goat lens and human erythrocytes. In goat lens, utilization of nicotinamine adenine dinucleotide phosphate (NADPH) and aldose reductase inhibition was assayed. In human erythrocytes, sorbitol formation was measured as an index of aldose reductase activity under normoglycemic and hyperglycemic conditions. Ability of juices in inhibiting oxidative damage to deoxyribose sugar and calf thymus DNA and inhibitory activity against hydrogen peroxide induced hemolysis of erythrocytes was also analysed. Phytochemical contents like total polyphenol, total flavonoid and total protein were measured to find their influence on biological activities. Results: Vegetables’ juice displayed varying degrees of inhibitory potentials in mitigating NADPH dependent catalytic activity of aldose reductase in goat lens, accumulation of sorbitol in human erythrocytes under different glucose concentrations; Fenton-reaction induced oxidative damage to deoxyribose sugar, and calf thymus DNA. Substantial variations in vegetables phytochemicals content were also noticed in this study. Conclusions: Vegetables’ juice possesses potent activities in influencing polyol pathway by various mechanisms in favour of reducing development of oxidative stress independent of their inherent antioxidative properties. Juice of ivy gourd followed by green cucumber and ridge gourd were among the most potent for they displayed strong activities on various parameters analysed in this study. These vegetables’ juice may become part of mechanism-based complementary antioxidant therapy to prevent development of diabetic complications. PMID:24991118

Tiwari, Ashok K.; Kumar, D. Anand; Sweeya, Pisupati S.; Chauhan, H. Anusha; Lavanya, V.; Sireesha, K.; Pavithra, K.; Zehra, Amtul

2014-01-01

342

Ancient and novel small RNA pathways compensate for the loss of piRNAs in multiple independent nematode lineages  

E-print Network

Pathway Evolution in Nematodes PLOS Biology | DOI:10.1371/journal.pbio.1002061 February 10, 2015 4 / 20 conserved in at least two out of C. elegans, D. melanogaster, and Homo sapiens as likely ances- tral bilaterian miRNAs. The majority were conserved... , grouped by seed in nematodes. The family is named after the most abundantH. sapiens family member, or the human member if noH. sapiensmember exists. The colour bar indicates conservation of a miRNA in C. elegans, D. melanogaster, H. sapiens or a...

Sarkies, Peter; Selkirk, Murray E.; Jones, John T; Blok, Vivian; Boothby, Thomas; Goldstein, Bob; Hanelt, Ben; Ardila-Garcia, Alex; M. Fast, Naomi; M. Schiffer, Phillip; Kraus, Christopher; Taylor, Mark J.; Koutsovoulos, Georgios; Blaxter, Mark L.; Miska, Eric A.

2015-02-10

343

FCAT Retakes: Trends in Multiple Attempts at Satisfying FCAT Graduation Requirements. Research Brief. Volume 0805  

ERIC Educational Resources Information Center

According to Florida Law, students must pass the Grade 10 FCAT, among other academic requirements, in order to receive a standard high school diploma. Specifically, students must achieve a "passing" score of 300 or above on both the FCAT SSS Reading and the FCAT SSS Mathematics tests. Technically, students can retake the FCAT as many times as they…

Froman, Terry; Brown, Shelly

2009-01-01

344

Evaluating Multiple Indices from a Canopy Reflectance Sensor to Estimate Corn N Requirements  

Technology Transfer Automated Retrieval System (TEKTRAN)

With the increasing cost of fertilizer N, there is a renewed emphasis on developing new technologies for quantifying in-season N requirements for corn. The objectives of this research are (i) to evaluate different vegetative indices derived from an active reflectance sensor in estimating in-season N...

345

Multiple Amidated Neuropeptides Are Required for Normal Circadian Locomotor Rhythms in Drosophila  

Microsoft Academic Search

In Drosophila, the amidated neuropeptide pigment dispersing factor (PDF) is expressed by the ventral subset of lateral pace- maker neurons and is required for circadian locomotor rhythms. Residual rhythmicity in pdf mutants likely reflects the activity of other neurotransmitters. We asked whether other neuropep- tides contribute to such auxiliary mechanisms. We used the gal4\\/UAS system to create mosaics for the

Paul H. Taghert; Randall S. Hewes; Jae H. Park; Martha A. O'Brien; Mei Han; Molly E. Peck

2001-01-01

346

Complete reversal of epithelial to mesenchymal transition requires inhibition of both ZEB expression and the Rho pathway  

Microsoft Academic Search

BACKGROUND: Epithelial to Mesenchymal Transition (EMT) induced by Transforming Growth Factor-? (TGF-?) is an important cellular event in organogenesis, cancer, and organ fibrosis. The process to reverse EMT is not well established. Our purpose is to define signaling pathways and transcription factors that maintain the TGF-?-induced mesenchymal state. RESULTS: Inhibitors of five kinases implicated in EMT, TGF-? Type I receptor

Shreyas Das; Bryan N Becker; F Michael Hoffmann; Janet E Mertz

2009-01-01

347

Requirements and potential development pathways for fission energy supply infrastructures of the 21st century - a systems viewpoint.  

SciTech Connect

Using an energy supply systems approach, we envision attributes and characteristic needs of a future global fission-based energy supply infrastructure, enumerate potential pathways for meeting those needs, and identify the underlying enabling science and technology developments for R and D efforts to meet the needs.

Wade, D. C.

1999-06-14

348

Whole gene expression profile in blood reveals multiple pathways deregulation in R6/2 mouse model  

PubMed Central

Background Huntington Disease (HD) is a progressive neurological disorder, with pathological manifestations in brain areas and in periphery caused by the ubiquitous expression of mutant Huntingtin protein. Transcriptional dysregulation is considered a key molecular mechanism responsible of HD pathogenesis but, although numerous studies investigated mRNA alterations in HD, so far none evaluated a whole gene expression profile in blood of R6/2 mouse model. Findings To discover novel pathogenic mechanisms and potential peripheral biomarkers useful to monitor disease progression or drug efficacy, a microarray study was performed in blood of R6/2 at manifest stage and wild type littermate mice. This approach allowed to propose new peripheral molecular processes involved in HD and to suggest different panels of candidate biomarkers. Among the discovered deregulated processes, we focused on specific ones: complement and coagulation cascades, PPAR signaling, cardiac muscle contraction, and dilated cardiomyopathy pathways. Selected genes derived from these pathways were additionally investigated in other accessible tissues to validate these matrices as source of biomarkers, and in brain, to link central and peripheral disease manifestations. Conclusions Our findings validated the skeletal muscle as suitable source to investigate peripheral transcriptional alterations in HD and supported the hypothesis that immunological alteration may contribute to neurological degeneration. Moreover, the identification of altered signaling in mouse blood enforce R6/2 transgenic mouse as a powerful HD model while suggesting novel disease biomarkers for pre-clinical investigation. PMID:24252798

2013-01-01

349

Knockdown of Human TCF4 Affects Multiple Signaling Pathways Involved in Cell Survival, Epithelial to Mesenchymal Transition and Neuronal Differentiation  

PubMed Central

Haploinsufficiency of TCF4 causes Pitt-Hopkins syndrome (PTHS): a severe form of mental retardation with phenotypic similarities to Angelman, Mowat-Wilson and Rett syndromes. Genome-wide association studies have also found that common variants in TCF4 are associated with an increased risk of schizophrenia. Although TCF4 is transcription factor, little is known about TCF4-regulated processes in the brain. In this study we used genome-wide expression profiling to determine the effects of acute TCF4 knockdown on gene expression in SH-SY5Y neuroblastoma cells. We identified 1204 gene expression changes (494 upregulated, 710 downregulated) in TCF4 knockdown cells. Pathway and enrichment analysis on the differentially expressed genes in TCF4-knockdown cells identified an over-representation of genes involved in TGF-? signaling, epithelial to mesenchymal transition (EMT) and apoptosis. Among the most significantly differentially expressed genes were the EMT regulators, SNAI2 and DEC1 and the proneural genes, NEUROG2 and ASCL1. Altered expression of several mental retardation genes such as UBE3A (Angelman Syndrome), ZEB2 (Mowat-Wilson Syndrome) and MEF2C was also found in TCF4-depleted cells. These data suggest that TCF4 regulates a number of convergent signaling pathways involved in cell differentiation and survival in addition to a subset of clinically important mental retardation genes. PMID:24058414

Forrest, Marc P.; Waite, Adrian J.; Martin-Rendon, Enca; Blake, Derek J.

2013-01-01

350

Multiple driving forces required for efficient secretion of autotransporter virulence proteins.  

PubMed

Autotransporter (AT) proteins are a broad class of virulence proteins from Gram-negative bacterial pathogens that require their own C-terminal transmembrane domain to translocate their N-terminal passenger across the bacterial outer membrane (OM). But given the unavailability of ATP or a proton gradient across the OM, it is unknown what energy source(s) drives this process. Here we used a combination of computational and experimental approaches to quantitatively compare proposed AT OM translocation mechanisms. We show directly for the first time that when translocation was blocked an AT passenger remained unfolded in the periplasm. We demonstrate that AT secretion is a kinetically controlled, non-equilibrium process coupled to folding of the passenger and propose a model connecting passenger conformation to secretion kinetics. These results reconcile seemingly contradictory reports regarding the importance of passenger folding as a driving force for OM translocation but also reveal that another energy source is required to initiate translocation. PMID:25670852

Drobnak, Igor; Braselmann, Esther; Clark, Patricia L

2015-04-17

351

RECOGNITION AND PHAGOCYTOSIS OF APOPTOTIC T CELLS BY RESIDENT MURINE TISSUE MACROPHAGES REQUIRES MULTIPLE SIGNAL TRANSDUCTION EVENTS  

PubMed Central

Macrophages (Mø) ingest apoptotic cells with unique effects on their cytokine production, but the signaling pathways involved are virtually unknown. Signal transduction in response to recognition of apoptotic thymocytes by resident murine alveolar (AMø) or peritoneal (PMø) Mø was studied by in vitro phagocytosis assay. Phagocytosis was decreased in a dose-dependent and non-toxic fashion by inhibiting phosphatidylinositol 3 kinase (wortmannin and LY294002), protein tyrosine phosphorylation (herbimycin A, genistein, piceatannol and, for AMø only, PP2), and protein kinase C (staurosporine, Gö 6976 and calphostin C). Exposure of Mø to apoptotic or heat-killed thymocytes, but not to viable thymocytes, rapidly activated ERK1/2, as detected by specific phosphorylation, but did not activate NF-?B or MAP kinases p38 or JNK. Mø phagocytosis of apoptotic T cells requires tyrosine, serine/threonine, and lipid phosphorylation. Mø recognition of apoptotic T cells triggers rapid but limited MAP kinase activation. PMID:11994514

Hu, Bin; Punturieri, Antonello; Todt, Jill; Sonstein, Joanne; Polak, Timothy; Curtis, Jeffrey L.

2015-01-01

352

Activation of the furin endoprotease is a multiple-step process: requirements for acidification and internal propeptide cleavage.  

PubMed Central

Activation of furin requires autoproteolytic cleavage of its 83-amino acid propeptide at the consensus furin site, Arg-Thr-Lys-Arg107/. This RER-localized cleavage is necessary, but not sufficient, for enzyme activation. Rather, full activation of furin requires exposure to, and correct routing within, the TGN/endosomal system. Here, we identify the steps in addition to the initial propeptide cleavage necessary for activation of furin. Exposure of membrane preparations containing an inactive RER-localized soluble furin construct to either: (i) an acidic and calcium-containing environment characteristic of the TGN; or (ii) mild trypsinization at neutral pH, resulted in the activation of the endoprotease. Taken together, these results suggest that the pH drop facilitates the removal of a furin inhibitor. Consistent with these findings, following cleavage in the RER, the furin propeptide remains associated with the enzyme and functions as a potent inhibitor of the endoprotease. Co-immunoprecipitation studies coupled with analysis by mass spectrometry show that release of the propeptide at acidic pH, and hence activation of furin, requires a second cleavage within the autoinhibitory domain at a site containing a P6 arginine (-Arg70-Gly-Val-Thr-Lys-Arg75/-). The significance of this cleavage in regulating the compartment-specific activation of furin, and the relationship of the furin activation pathway to those of other serine endoproteases are discussed. PMID:9130696

Anderson, E D; VanSlyke, J K; Thulin, C D; Jean, F; Thomas, G

1997-01-01

353

Initiation of biofilm formation in Pseudomonas fluorescens WCS365 proceeds via multiple, convergent signalling pathways: a genetic analysis  

Microsoft Academic Search

Summary Populations of surface-attached microorganisms com- prising either single or multiple species are commonly referred to as biofilms. Using a simple assay for the initiation of biofilm formation (e.g. attachment to an abiotic surface) by Pseudomonas fluorescens strain WCS365, we have shown that: (i) P. fluorescens can form biofilms on an abiotic surface when grown on a range of nutrients;

George A. O'Toole; Roberto Kolter

1998-01-01

354

Is multiple-sequence alignment required for accurate inference of phylogeny?  

PubMed

The process of inferring phylogenetic trees from molecular sequences almost always starts with a multiple alignment of these sequences but can also be based on methods that do not involve multiple sequence alignment. Very little is known about the accuracy with which such alignment-free methods recover the correct phylogeny or about the potential for increasing their accuracy. We conducted a large-scale comparison of ten alignment-free methods, among them one new approach that does not calculate distances and a faster variant of our pattern-based approach; all distance-based alignment-free methods are freely available from http://www.bioinformatics.org.au (as Python package decaf+py). We show that most methods exhibit a higher overall reconstruction accuracy in the presence of high among-site rate variation. Under all conditions that we considered, variants of the pattern-based approach were significantly better than the other alignment-free methods. The new pattern-based variant achieved a speed-up of an order of magnitude in the distance calculation step, accompanied by a small loss of tree reconstruction accuracy. A method of Bayesian inference from k-mers did not improve on classical alignment-free (and distance-based) methods but may still offer other advantages due to its Bayesian nature. We found the optimal word length k of word-based methods to be stable across various data sets, and we provide parameter ranges for two different alphabets. The influence of these alphabets was analyzed to reveal a trade-off in reconstruction accuracy between long and short branches. We have mapped the phylogenetic accuracy for many alignment-free methods, among them several recently introduced ones, and increased our understanding of their behavior in response to biologically important parameters. In all experiments, the pattern-based approach emerged as superior, at the expense of higher resource consumption. Nonetheless, no alignment-free method that we examined recovers the correct phylogeny as accurately as does an approach based on maximum-likelihood distance estimates of multiply aligned sequences. PMID:17454975

Höhl, Michael; Ragan, Mark A

2007-04-01

355

Multiple decomposition pathways for the oxenium ion precursor O-(4-(4'-methylphenyl)phenyl)-N-methanesulfonylhydroxylamine.  

PubMed

Although O-arylhydroxylamine derivatives have been claimed to be sources of oxenium ions in a large number of studies, it is not clear that the products of these reactions are due to oxenium ions. Previously, we had shown through azide trapping studies that the quinol ester 2a and the title compound 3a generate the oxenium ion 1a. The ester 2a exclusively generates 1a in water and is also a photoprecursor of 1a in water. This is not true of 3a. The oxenium ion pathway accounts for a significant fraction of the reaction of 3a under neutral and acidic pH conditions, but there are three other pathways that account for hydrolysis of 3a. Both 3a and its conjugate base 3a(-) are present in aqueous solution under mild pH conditions. In addition to the oxenium ion product 4a, two other significant products are generated: the phenol 6a and the rearrangement product 8a. Both 4a and 8a are generated exclusively from 3a, whereas 6a is generated from both 3a and 3a(-). Azide trapping studies show that 6a and 8a are not generated from the oxenium ion. The phenol 6a is generated by two paths, one involving an apparent radical intermediate 7a and the other through a stepwise alpha-elimination pathway through 3a(-). The rearrangement product 8a is generated either through a concerted rearrangement or via an ion-pair rearrangement. Photolysis of 3a does not generate 1a. The only products of photolysis of 3a in water are 6a (major) and 8a (minor). The weak O-N bond of 3a is susceptible to homolysis under photolysis conditions, and the radical 7a is observed after laser flash photolysis of 3a. The cation 1a that is observed during laser flash photolysis experiments on 2a cannot be detected during similar experiments on 3a. These results suggest that the previous attribution of oxenium ions as the source of the decomposition products of other O-arylhydroxylamine derivatives in aromatic solvents via thermolysis or acid-catalyzed decomposition may not be correct. PMID:19775151

Wang, Yue-Ting; Novak, Michael

2009-10-16

356

Differentiation of central nervous system neuronal cells by fibroblast-derived growth factor requires at least two signaling pathways: roles for Ras and Src.  

PubMed Central

To evaluate the role of mitogen-activated protein (MAP) kinase and other signaling pathways in neuronal cell differentiation by basic fibroblast-derived growth factor (bFGF), we used a conditionally immortalized cell line from rat hippocampal neurons (H19-7). Previous studies have shown that activation of MAP kinase kinase (MEK) is insufficient to induce neuronal differentiation of H19-7 cells. To test the requirement for MEK and MAP kinase (ERK1 and ERK2), H19-7 cells were treated with the MEK inhibitor PD098059. Although the MEK inhibitor blocked the induction of differentiation by constitutively activated Raf, the H19-7 cells still underwent differentiation by bFGF. These results suggest that an alternative pathway is utilized by bFGF for differentiation of the hippocampal neuronal cells. Expression in the H19-7 cells of a dominant-negative Ras (N17-Ras) or Raf (C4-Raf) blocked differentiation by bFGF, suggesting that Ras and probably Raf are required. Expression of dominant-negative Src (pcSrc295Arg) or microinjection of an anti-Src antibody blocked differentiation by bFGF in H19-7 cells, indicating that bFGF also signals through a Src kinase-mediated pathway. Although neither constitutively activated MEK (MEK-2E) nor v-Src was sufficient individually to differentiate the H19-7 cells, coexpression of constitutively activated MEK and v-Src induced neurite outgrowth. These results suggest that (i) activation of MAP kinase (ERK1 and ERK2) is neither necessary nor sufficient for differentiation by bFGF; (ii) activation of Src kinases is necessary but not sufficient for differentiation by bFGF; and (iii) differentiation of H19-7 neuronal cells by bFGF requires at least two signaling pathways activated by Ras and Src. PMID:9234720

Kuo, W L; Chung, K C; Rosner, M R

1997-01-01

357

The Endosomal Sorting Complex Required for Transport Pathway Mediates Chemokine Receptor CXCR4-promoted Lysosomal Degradation of the Mammalian Target of Rapamycin Antagonist DEPTOR.  

PubMed

G protein-coupled receptor (GPCR) signaling mediates many cellular functions, including cell survival, proliferation, and cell motility. Many of these processes are mediated by GPCR-promoted activation of Akt signaling by mammalian target of rapamycin complex 2 (mTORC2) and the phosphatidylinositol 3-kinase (PI3K)/phosphoinositide-dependent kinase 1 (PDK1) pathway. However, the molecular mechanisms by which GPCRs govern Akt activation by these kinases remain poorly understood. Here, we show that the endosomal sorting complex required for transport (ESCRT) pathway mediates Akt signaling promoted by the chemokine receptor CXCR4. Pharmacological inhibition of heterotrimeric G protein G?i or PI3K signaling and siRNA targeting ESCRTs blocks CXCR4-promoted degradation of DEPTOR, an endogenous antagonist of mTORC2 activity. Depletion of ESCRTs by siRNA leads to increased levels of DEPTOR and attenuated CXCR4-promoted Akt activation and signaling, consistent with decreased mTORC2 activity. In addition, ESCRTs likely have a broad role in Akt signaling because ESCRT depletion also attenuates receptor tyrosine kinase-promoted Akt activation and signaling. Our data reveal a novel role for the ESCRT pathway in promoting intracellular signaling, which may begin to identify the signal transduction pathways that are important in the physiological roles of ESCRTs and Akt. PMID:25605718

Verma, Rita; Marchese, Adriano

2015-03-13

358

Ggamma1, a downstream target for the hmgcr-isoprenoid biosynthetic pathway, is required for releasing the Hedgehog ligand and directing germ cell migration.  

PubMed

The isoprenoid biosynthetic pathway leading from the production of mevalonate by HMGCoA reductase (Hmgcr) to the geranylation of the G protein subunit, Ggamma1, plays an important role in cardiac development in the fly. Hmgcr has also been implicated in the release of the signaling molecule Hedgehog (Hh) from hh expressing cells and in the production of an attractant that directs primordial germ cells to migrate to the somatic gonadal precursor cells (SGPs). The studies reported here indicate that this same hmgcr-->Ggamma1 pathway provides a novel post-translational mechanism for modulating the range and activity of the Hh signal produced by hh expressing cells. We show that, like hmgcr, ggamma1 and quemao (which encodes the enzyme, geranylgeranyl diphosphate synthetase, that produces the substrate for geranylation of Ggamma1) are components of the hh signaling pathway and are required for the efficient release of the Hh ligand from hh expressing cells. We also show that the hmgcr-->Ggamma1 pathway is linked to production of the germ cell attractant by the SGPs through its ability to enhance the potency of the Hh signal. We show that germ cell migration is disrupted by the loss or gain of ggamma1 activity, by trans-heterozygous combinations between ggamma1 and either hmgcr or hh mutations, and by ectopic expression of dominant negative Ggamma1 proteins that cannot be geranylated. PMID:19132091

Deshpande, Girish; Godishala, Anuradha; Schedl, Paul

2009-01-01

359

Requirement for safety monitoring for approved multiple sclerosis therapies: an overview  

PubMed Central

During the last two decades, treatment options for patients with multiple sclerosis (MS) have broadened tremendously. All agents that are currently approved for clinical use have potential side effects, and a careful risk–benefit evaluation is part of a decision algorithm to identify the optimal treatment choice for an individual patient. Whereas glatiramer acetate and interferon beta preparations have been used in MS for decades and have a proven safety record, more recently approved drugs appear to be more effective, but potential risks might be more severe. The potential complications of some novel therapies might not even have been identified to their full extent. This review is aimed at the clinical neurologist in that it offers insights into potential adverse events of each of the approved MS therapeutics: interferon beta, glatiramer acetate, mitoxantrone, natalizumab, fingolimod and teriflunomide, as well as recently approved therapeutics such as dimethyl fumarate and alemtuzumab. It also provides recommendations for monitoring the different drugs during therapy in order to avoid common side effects. PMID:24102425

Rommer, P S; Zettl, U K; Kieseier, B; Hartung, H-P; Menge, T; Frohman, E; Greenberg, B M; Hemmer, B; Stüve, O

2014-01-01

360

Requirement for safety monitoring for approved multiple sclerosis therapies: an overview.  

PubMed

During the last two decades, treatment options for patients with multiple sclerosis (MS) have broadened tremendously. All agents that are currently approved for clinical use have potential side effects, and a careful risk-benefit evaluation is part of a decision algorithm to identify the optimal treatment choice for an individual patient. Whereas glatiramer acetate and interferon beta preparations have been used in MS for decades and have a proven safety record, more recently approved drugs appear to be more effective, but potential risks might be more severe. The potential complications of some novel therapies might not even have been identified to their full extent. This review is aimed at the clinical neurologist in that it offers insights into potential adverse events of each of the approved MS therapeutics: interferon beta, glatiramer acetate, mitoxantrone, natalizumab, fingolimod and teriflunomide, as well as recently approved therapeutics such as dimethyl fumarate and alemtuzumab. It also provides recommendations for monitoring the different drugs during therapy in order to avoid common side effects. PMID:24102425

Rommer, P S; Zettl, U K; Kieseier, B; Hartung, H-P; Menge, T; Frohman, E; Greenberg, B M; Hemmer, B; Stüve, O

2014-03-01

361

RIP4 is a target of multiple signal transduction pathways in keratinocytes: Implications for epidermal differentiation and cutaneous wound repair  

SciTech Connect

Receptor interacting protein 4 (RIP4) is an important regulator of epidermal morphogenesis during embryonic development. We could previously show that expression of the rip4 gene is strongly downregulated in cutaneous wound repair, which might be initiated by a broad variety of growth factors and cytokines. Here, we demonstrate that in keratinocytes, rip4 expression is controlled by a multitude of different signal transduction pathways, such as the p38 mitogen-activated protein kinase (MAPK) and the nuclear factor kappa B (NF-{kappa}B) cascade, in a unique and specific manner. Furthermore, we show that the steroid dexamethasone abolishes the physiological rip4 downregulation after injury and might thus contribute to the phenotype of reduced and delayed wound reepithelialization seen in glucocorticoid-treated patients. As a whole, our data indicate that rip4 expression is regulated in a complex manner, which might have therapeutic implications.

Adams, Stephanie [Charite, University Medicine Berlin, Institute of Physiology, Arnimallee 22, D-14195 Berlin (Germany)] [Charite, University Medicine Berlin, Institute of Physiology, Arnimallee 22, D-14195 Berlin (Germany); Munz, Barbara, E-mail: barbara.munz@charite.de [Charite, University Medicine Berlin, Institute of Physiology, Arnimallee 22, D-14195 Berlin (Germany)] [Charite, University Medicine Berlin, Institute of Physiology, Arnimallee 22, D-14195 Berlin (Germany)

2010-01-01

362

Multiple Transport Pathways for Mediating Intracellular pH Homeostasis: The Contribution of H+/ion Exchangers  

PubMed Central

Intracellular pH homeostasis is an essential process in all plant cells. The transport of H+ into intracellular compartments is critical for providing pH regulation. The maintenance of correct luminal pH in the vacuole and in compartments of the secretory/endocytic pathway is important for a variety of cellular functions including protein modification, sorting, and trafficking. It is becoming increasingly evident that coordination between primary H+ pumps, most notably the V-ATPase, and secondary ion/H+ exchangers allows this endomembrane pH maintenance to occur. This article describes some of the recent insights from the studies of plant cation/H+ exchangers and anion/H+ exchangers that demonstrate the fundamental roles of these transporters in pH homeostasis within intracellular compartments. PMID:22645567

Pittman, Jon K.

2012-01-01

363

Genetic Analyses of Interferon Pathway-Related Genes Reveals Multiple New Loci Associated with Systemic Lupus Erythematosus (SLE)  

PubMed Central

Objective The overexpression of interferon (IFN)-inducible genes is a prominent feature of SLE, serves as a marker for active and more severe disease, and is also observed in other autoimmune and inflammatory conditions. The genetic variations responsible for sustained activation of IFN responsive genes are unknown. Methods We systematically evaluated association of SLE with a total of 1,754 IFN-pathway related genes, including IFN-inducible genes known to be differentially expressed in SLE patients and their direct regulators. We performed a three-stage design where two cohorts (total n=939 SLE cases, 3,398 controls) were analyzed independently and jointly for association with SLE, and the results were adjusted for the number of comparisons. Results A total of 16,137 SNPs passed all quality control filters of which 316 demonstrated replicated association with SLE in both cohorts. Nine variants were further genotyped for confirmation in an average of 1,316 independent SLE cases and 3,215 independent controls. Association with SLE was confirmed for several genes, including the transmembrane receptor CD44 (rs507230, P = 3.98×10?12), cytokine pleiotrophin (PTN) (rs919581, P = 5.38×10?04), the heat-shock DNAJA1 (rs10971259, P = 6.31×10?03), and the nuclear import protein karyopherin alpha 1 (KPNA1) (rs6810306, P = 4.91×10?02). Conclusion This study expands the number of candidate genes associated with SLE and highlights the potential of pathway-based approaches for gene discovery. Identification of the causal alleles will help elucidate the molecular mechanisms responsible for activation of the IFN system in SLE. PMID:21437871

Ramos, Paula S.; Williams, Adrienne H.; Ziegler, Julie T.; Comeau, Mary E.; Guy, Richard T.; Lessard, Christopher J.; Li, He; Edberg, Jeffrey C.; Zidovetzki, Raphael; Criswell, Lindsey A.; Gaffney, Patrick M.; Graham, Deborah Cunninghame; Graham, Robert R.; Kelly, Jennifer A.; Kaufman, Kenneth M.; Brown, Elizabeth E.; Alarcón, Graciela S.; Petri, Michelle A.; Reveille, John D.; McGwin, Gerald; Vilá, Luis M.; Ramsey-Goldman, Rosalind; Jacob, Chaim O.; Vyse, Timothy J.; Tsao, Betty P.; Harley, John B.; Kimberly, Robert P.; Alarcón-Riquelme, Marta E.; Langefeld, Carl D.; Moser, Kathy L.

2011-01-01

364

Adenosine is required for sustained inflammasome activation via the A2A receptor and the HIF-1? pathway  

NASA Astrophysics Data System (ADS)

Inflammasome pathways are important in chronic diseases; however, it is not known how the signalling is sustained after initiation. Inflammasome activation is dependent on stimuli such as lipopolysaccharide (LPS) and ATP that provide two distinct signals resulting in rapid production of interleukin (IL)-1?, with the lack of response to repeat stimulation. Here we report that adenosine is a key regulator of inflammasome activity, increasing the duration of the inflammatory response via the A2A receptor. Adenosine does not replace signals provided by stimuli such as LPS or ATP but sustains inflammasome activity via a cAMP/PKA/CREB/HIF-1? pathway. In the setting of the lack of IL-1? responses after previous exposure to LPS, adenosine can supersede this tolerogenic state and drive IL-1? production. These data reveal that inflammasome activity is sustained, after initial activation, by A2A receptor-mediated signalling.

Ouyang, Xinshou; Ghani, Ayaz; Malik, Ahsan; Wilder, Tuere; Colegio, Oscar Rene; Flavell, Richard Anthony; Cronstein, Bruce Neil; Mehal, Wajahat Zafar

2013-12-01

365

Role of the phosphatidylinositol 3-kinase\\/Akt and mTOR\\/P70S6-kinase pathways in the proliferation and apoptosis in multiple myeloma  

Microsoft Academic Search

Multiple myeloma (MM) is a plasma cell malignancy preliminary localized in the bone marrow and characterized by its capacity to disseminate. IL-6 and IGF-1 have been shown to mediate proliferative and anti-apoptotic signals in plasmocytes. However, in primary plasma-cell leukemia (PCL) and in end-stage aggressive extramedullar disease, the cytokine requirement for both effects may be not mandatory. This suggests that

Frédéric Pene; Yann-Erick Claessens; Odile Muller; Franck Viguié; Patrick Mayeux; François Dreyfus; Catherine Lacombe; Didier Bouscary

2002-01-01

366

Differential requirements of MyD88 and TRIF pathways in TLR4-mediated immune responses in murine B cells.  

PubMed

LPS stimulates the TLR4/Myeloid differentiation protein-2 (MD-2) complex and promotes a variety of immune responses in B cells. TLR4 has two main signaling pathways, MyD88 and Toll/IL-1R (TIR)-domain-containing adaptor-inducing interferon-? (TRIF) pathways, but relatively few studies have examined these pathways in B cells. In this study, we investigated MyD88- or TRIF-dependent LPS responses in B cells by utilizing their knockout mice. Compared with wild-type (WT) B cells, MyD88(-/-) B cells were markedly impaired in up-regulation of CD86 and proliferation induced by lipid A moiety of LPS. TRIF(-/-) B cells were also impaired in these responses compared with WT B cells, but showed better responses than MyD88(-/-) B cells. Regarding class switch recombination (CSR) elicited by lipid A plus IL-4, MyD88(-/-) B cells showed similar patterns of CSR to WT B cells. However, TRIF(-/-) B cells showed the impaired in the CSR. Compared with WT and MyD88(-/-) B cells, TRIF(-/-) B cells exhibited reduced cell division, fewer IgG1(+) cells per division, and decreased activation-induced cytidine deaminase (Aicda) mRNA expression in response to lipid A plus IL-4. Finally, IgG1 production to trinitrophenyl (TNP)-LPS immunization was impaired in TRIF(-/-) mice, while MyD88(-/-) mice exhibited increased IgG1 production. Thus, MyD88 and TRIF pathways differently regulate TLR4-induced immune responses in B cells. PMID:25448706

Yanagibashi, Tsutomu; Nagai, Yoshinori; Watanabe, Yasuharu; Ikutani, Masashi; Hirai, Yoshikatsu; Takatsu, Kiyoshi

2015-01-01

367

Extended Pausing by Humans on Multiple Fixed-Ratio Schedules with Varied Reinforcer Magnitude and Response Requirements  

PubMed Central

We conducted three experiments to reproduce and extend Perone and Courtney's (1992) study of pausing at the beginning of fixed-ratio schedules. In a multiple schedule with unequal amounts of food across two components, they found that pigeons paused longest in the component associated with the smaller amount of food (the lean component), but only when it was preceded by the rich component. In our studies, adults with mild intellectual disabilities responded on a touch-sensitive computer monitor to produce money. In Experiment 1, the multiple-schedule components differed in both response requirement and reinforcer magnitude (i.e., the rich component required fewer responses and produced more money than the lean component). Effects shown with pigeons were reproduced in all 7 participants. In Experiment 2, we removed the stimuli that signaled the two schedule components, and participants' extended pausing was eliminated. In Experiment 3, to assess sensitivity to reinforcer magnitude versus fixed-ratio size, we presented conditions with equal ratio sizes but disparate magnitudes and conditions with equal magnitudes but disparate ratio sizes. Sensitivity to these manipulations was idiosyncratic. The present experiments obtained schedule control in verbally competent human participants and, despite procedural differences, we reproduced findings with animal participants. We showed that pausing is jointly determined by past conditions of reinforcement and stimuli correlated with upcoming conditions. PMID:21541121

Williams, Dean C; Saunders, Kathryn J; Perone, Michael

2011-01-01

368

Mature ribosomes are selectively degraded upon starvation by an autophagy pathway requiring the Ubp3p/Bre5p ubiquitin protease.  

PubMed

Eukaryotic cells use autophagy and the ubiquitin-proteasome system (UPS) as their major protein degradation pathways. Whereas the UPS is required for the rapid degradation of proteins when fast adaptation is needed, autophagy pathways selectively remove protein aggregates and damaged or excess organelles. However, little is known about the targets and mechanisms that provide specificity to this process. Here we show that mature ribosomes are rapidly degraded by autophagy upon nutrient starvation in Saccharomyces cerevisiae. Surprisingly, this degradation not only occurs by a non-selective mechanism, but also involves a novel type of selective autophagy, which we term 'ribophagy'. A genetic screen revealed that selective degradation of ribosomes requires catalytic activity of the Ubp3p/Bre5p ubiquitin protease. Although ubp3Delta and bre5Delta cells strongly accumulate 60S ribosomal particles upon starvation, they are proficient in starvation sensing and in general trafficking and autophagy pathways. Moreover, ubiquitination of several ribosomal subunits and/or ribosome-associated proteins was specifically enriched in ubp3Delta cells, suggesting that the regulation of ribophagy by ubiquitination may be direct. Interestingly, ubp3Delta cells are sensitive to rapamycin and nutrient starvation, implying that selective degradation of ribosomes is functionally important in vivo. Taken together, our results suggest a link between ubiquitination and the regulated degradation of mature ribosomes by autophagy. PMID:18391941

Kraft, Claudine; Deplazes, Anna; Sohrmann, Marc; Peter, Matthias

2008-05-01

369

Targeting Vascular Endothelial Growth Factor Receptor 2 and Protein Kinase D1 Related Pathways by a Multiple Kinase Inhibitor in Angiogenesis and Inflammation Related Processes In Vitro  

PubMed Central

Emerging evidence suggests that the vascular endothelial growth factor receptor 2 (VEGFR2) and protein kinase D1 (PKD1) signaling axis plays a critical role in normal and pathological angiogenesis and inflammation related processes. Despite all efforts, the currently available therapeutic interventions are limited. Prior studies have also proved that a multiple target inhibitor can be more efficient compared to a single target one. Therefore, development of novel inflammatory pathway-specific inhibitors would be of great value. To test this possibility, we screened our molecular library using recombinant kinase assays and identified the previously described compound VCC251801 with strong inhibitory effect on both VEGFR2 and PKD1. We further analyzed the effect of VCC251801 in the endothelium-derived EA.hy926 cell line and in different inflammatory cell types. In EA.hy926 cells, VCC251801 potently inhibited the intracellular activation and signaling of VEGFR2 and PKD1 which inhibition eventually resulted in diminished cell proliferation. In this model, our compound was also an efficient inhibitor of in vitro angiogenesis by interfering with endothelial cell migration and tube formation processes. Our results from functional assays in inflammatory cellular models such as neutrophils and mast cells suggested an anti-inflammatory effect of VCC251801. The neutrophil study showed that VCC251801 specifically blocked the immobilized immune-complex and the adhesion dependent TNF-? -fibrinogen stimulated neutrophil activation. Furthermore, similar results were found in mast cell degranulation assay where VCC251801 caused significant reduction of mast cell response. In summary, we described a novel function of a multiple kinase inhibitor which strongly inhibits the VEGFR2-PKD1 signaling and might be a novel inhibitor of pathological inflammatory pathways. PMID:25874616

Varga, Attila; Gyulavári, Pál; Greff, Zoltán; Futosi, Krisztina; Németh, Tamás; Simon-Szabó, Laura; Kerekes, Krisztina; Szántai-Kis, Csaba; Brauswetter, Diána; Kokas, Márton; Borbély, Gábor; Erdei, Anna; Mócsai, Attila; Kéri, György; Vántus, Tibor

2015-01-01

370

A highly conserved family of domains related to the DNA-glycosylase fold helps predict multiple novel pathways for RNA modifications  

PubMed Central

A protein family including mammalian NEMF, Drosophila caliban, yeast Tae2, and bacterial FpbA-like proteins was first defined over a decade ago and found to be universally distributed across the three domains/superkingdoms of life. Since its initial characterization, this family of proteins has been tantalizingly linked to a wide range of biochemical functions. Tapping the enormous wealth of genome information that has accumulated since the initial characterization of these proteins, we perform a detailed computational analysis of the family, identifying multiple conserved domains. Domains identified include an enzymatic domain related to the formamidopyrimidine (Fpg), MutM, and Nei/EndoVIII family of DNA glycosylases, a novel, predicted RNA-binding domain, and a domain potentially mediating protein–protein interactions. Through this characterization, we predict that the DNA glycosylase-like domain catalytically operates on double-stranded RNA, as part of a hitherto unknown base modification mechanism that probably targets rRNAs. At least in archaea, and possibly eukaryotes, this pathway might additionally include the AMMECR1 family of proteins. The predicted RNA-binding domain associated with this family is also observed in distinct architectural contexts in other proteins across phylogenetically diverse prokaryotes. Here it is predicted to play a key role in a new pathway for tRNA 4-thiouridylation along with TusA-like sulfur transfer proteins. PMID:24646681

Burroughs, A Maxwell; Aravind, L

2014-01-01

371

Modelling equilibrium shoreline response: application across multiple sites and minimum data collection requirements  

NASA Astrophysics Data System (ADS)

The ability to predict shoreline variability and trends for a range of potential future climate scenarios is of increasing interest to coastal scientists. Here we introduce a new shoreline equilibrium model driven by cross-shore processes via changes in non-dimensional fall velocity (i.e., sediment characteristics and wave steepness) and offshore wave power (Davidson et al., submitted). The equilibrium shoreline position is modeled based on a weighted time-average of past non-dimensional fall velocity following the work of Wright et al. (1985). When the prevailing wave conditions are steeper than the time varying equilibrium, the shoreline erodes as sand is expected to move offshore and form a breaker bar. Conversely, when waves are flatter, sand moves onshore and the shoreline builds seawards. The model is applied at a number of sites within Australia and the US to quantify model skill, and to examine free parameter sensitivity and generic transferability between differing sites. Further testing using real-world and synthetic data sets is used to determine the minimum data requirements for calibration of the model, providing useful guidance to future coastline monitoring program requirements. Model hindcasts at six locations within Australia indicate this simple cross-shore equilibrium shoreline model is capable of reproducing multi-year shoreline variability with significant skill. Shoreline variance explained by the model (currently driven only by cross-shore processes) is between 40% (downdrift of an Artificial surfing reef on an exposed open coast) to 66% percent (on a central location of a storm-driven embayed beach, Fig. 1).Hindcast results for the Narrabeen embayment at alongshore locations y=2200m (a), 2600m (b) and 3200m (c). R 2 ranged from 0.57 (y=2600m) to 0.66 (y=3200m). The thickness of the data curve (grey) indicates the potential measurement error.

Splinter, K.; Davidson, M. A.; Turner, I. L.

2012-12-01

372

Efficient in vitro repair of 7-hydro-8-oxodeoxyguanosine by human cell extracts: involvement of multiple pathways.  

PubMed Central

To investigate the repair of oxidative damage in DNA, we have established an in vitro assay utilizing human lymphoblastoid whole cell extracts and plasmid DNA damaged by exposure to methylene blue and visible light. This treatment has been shown to produce predominantly 7-hydro-8-oxodeoxyguanosine (8-oxodG) in double-stranded DNA at low levels of modification. DNA containing 1. 6 lesions per plasmid is substrate for efficient repair synthesis by cell extracts. The incorporation of dGMP is 2.7 +/- 0.5 times greater than the incorporation of dCMP, indicating an average repair patch of 3-4 nucleotides. Damage-specific nicking occurs within 15 min, while resynthesis is slower. The incorporation of dGMP increases linearly, while the incorporation of dCMP exhibits a distinct lag. Extracts from xeroderma pigmentosum (XP) complementation groups A and B exhibit 25 and 40%, respectively, of the incorporation of dCMP compared with normal extracts, but extracts from an XP-D cell line exhibit twice the activity. These data suggest that the efficient repair of 8-oxodG lesions observed in human cell extracts involves more than one pathway of base excision repair. PMID:9547279

Jaiswal, M; Lipinski, L J; Bohr, V A; Mazur, S J

1998-01-01

373

Activation of NOD1 by DAP contributes to myocardial ischemia/reperfusion injury via multiple signaling pathways.  

PubMed

NOD1 is a member of nucleotide-binding oligomerization domain-like receptors family that participates in many inflammatory processes. Previous studies demonstrated that NOD1 plays an important role in inflammatory cardiovascular diseases. However, its role in myocardial ischemia/reperfusion (I/R) injury remains unknown. The present study investigate whether NOD1 is involved in the pathogenesis of mouse myocardial I/R injury and the underlying mechanisms. Administration of NOD1 ligand (DAP) significantly enhanced myocardial I/R injury, as demonstrated by increased infarct size, the number of TUNEL-positive nuclei, caspase-3 activity, the infiltration of Mac-2- and IL-6-positive cells as compared with untreated heart or cardiomyocytes after I/R injury. In contrast, knockdown of NOD1 by siRNA markedly attenuated mimetic I/R induced cardiomyocyte apoptosis in vitro, indicating that NOD1 enhanced myocardial I/R injury partially through direct heart effects. These effects were partially associated with activation of JNK, p38 MAPK and NF-?B signaling pathways. Taken together, these results provide the first evidence that activation of intracellular sensor NOD1 enhances myocardial I/R injury and may provide novel therapeutic target for ameliorating the ischemic heart diseases. PMID:25608996

Yang, Hui; Li, Nan; Song, Li-Na; Wang, Lei; Tian, Cui; Tang, Chao-Shu; Du, Jie; Li, Hui-Hua; Yu, Xiao-Hong; Wang, Hong-Xia

2015-04-01

374

Stabilization of a prion strain of synthetic origin requires multiple serial passages.  

PubMed

Transmission of prions to a new host is frequently accompanied by strain adaptation, a phenomenon that involves reduction of the incubation period, a change in neuropathological features and, sometimes, tissue tropism. Here we show that a strain of synthetic origin (SSLOW), although serially transmitted within the same species, displayed the key attributes of the strain adaptation process. At least four serial passages were required to stabilize the strain-specific SSLOW phenotype. The biological titration of SSLOW revealed a correlation between clinical signs and accumulation of PrP(Sc) in brains of animals inoculated with high doses (10(-1)-10(-5) diluted brain material), but dissociation between the two processes at low dose inocula (10(-6)-10(-8) diluted brain material). At low doses, several asymptomatic animals harbored large amounts of PrP(Sc) comparable with those seen in the brains of terminally ill animals, whereas one clinically ill animal had very little, if any, PrP(Sc). In summary, the current study illustrates that the phenomenon of prion strain adaptation is more common than generally thought and could be observed upon serial transmission without changing the host species. When PrP(Sc) is seeded by recombinant PrP structures different from that of authentic PrP(Sc), PrP(Sc) properties continued to evolve for as long as four serial passages. PMID:22807452

Makarava, Natallia; Kovacs, Gabor G; Savtchenko, Regina; Alexeeva, Irina; Budka, Herbert; Rohwer, Robert G; Baskakov, Ilia V

2012-08-31

375

Single and multiple dose intravenous and oral pharmacokinetics of the hedgehog pathway inhibitor vismodegib in healthy female subjects  

PubMed Central

AIM Vismodegib has demonstrated clinical activity in patients with advanced basal cell carcinoma. The pharmacokinetics (PK) of vismodegib are non-linear. The objective of this study was to determine whether vismodegib PK change following repeated dosing by administering a tracer intravenous (i.v.) dose of 14C-vismodegib with single and multiple oral doses. METHODS Healthy post menopausal female subjects (n= 6/group) received either a single or daily 150 mg vismodegib oral dose with a 14C-labelled 10 µg i.v. bolus dose administered 2 h after the single or last oral dose (day 7). Plasma samples were assayed for vismodegib by LC-MS/MS and for 14C-vismodegib by accelerator mass spectrometry. RESULTS Following a single i.v. dose, mean clearance, volume of distribution and absolute bioavailability were 43.4 ml h?1, 16.4 l and 31.8%, respectively. Parallel concentration–time profiles following single oral and i.v. administration of vismodegib indicated elimination rate limited PK. Following i.v. administration at steady-state, mean clearance and volume of distribution were 78.5 ml h?1 and 26.8 l, respectively. Comparison of i.v. PK parameters after single and multiple oral dosing showed similar half-life, increased clearance and volume of distribution (81% and 63% higher, respectively) and decreased bioavailability (77% lower) after repeated dosing. Relative to single dose, the unbound fraction of vismodegib increased 2.4-fold with continuous daily dosing. CONCLUSION Vismodegib exhibited a long terminal half-life after oral and i.v. administration, moderate absolute bioavailability and non-linear PK after repeated dosing. Results from this study suggest that the non-linear PK of vismodegib result from two separate, non-linear processes, namely solubility limited absorption and high affinity, saturable plasma protein binding. PMID:22458643

Graham, Richard A; Hop, Cornelis E C A; Borin, Marie T; Lum, Bert L; Colburn, Dawn; Chang, Ilsung; Shin, Young G; Malhi, Vikram; Low, Jennifer A; Dresser, Mark J

2012-01-01

376

Recombinant factor VIIa enhances platelet deposition from flowing haemophilic blood but requires the contact pathway to promote fibrin deposition.  

PubMed

In prior microfluidic studies with haemophilic blood perfused over collagen, we found that a severe deficiency (<1% factor level) reduced platelet and fibrin deposition, while a moderate deficiency (1-5%) only reduced fibrin deposition. We investigated: (i) the differential effect of rFVIIa (0.04-20 nm) on platelet and fibrin deposition, and (ii) the contribution of the contact pathway to rFVIIa-induced haemophilic blood clotting. Haemophilic or healthy blood with low and high corn trypsin inhibitor (CTI, 4 or 40 ?g mL(-1) ) was perfused over collagen at an initial venous wall shear rate of 100 s(-1) . At 100 s(-1) wall shear rate, where FXIIa leads to thrombin production without added tissue factor, FXI-deficient blood (3%) or severely FVIII-deficient blood (<1%) produced no fibrin at either CTI level. Whereas rFVIIa potently enhanced platelet deposition, fibrin generation was not rescued. Distinct from the high CTI condition, engagement of the contact pathway (low CTI) in moderately FVIII-deficient (3%) or moderately FIX-deficient blood (5%) resulted in enhanced platelet and fibrin deposition following 4 nm rFVIIa supplementation. In mildly FVIII-deficient blood (15%) at <24 h since haemostatic therapy, rFVIIa enhanced both platelet and fibrin generation in either CTI condition although fibrin was produced more quickly and abundantly in low CTI. For tissue factor-free conditions of severe haemophilic blood clotting, we conclude that rFVIIa reliably generates low levels of 'signaling' thrombin sufficient to enhance platelet deposition on collagen, but is insufficient to drive fibrin polymerization unless potentiated by the contact pathway. PMID:25311576

Li, R; Panckeri, K A; Fogarty, P F; Diamond, S L

2015-03-01

377

Multiple neural oscillators and muscle feedback are required for the intestinal fed state motor program.  

PubMed

After a meal, the gastrointestinal tract exhibits a set of behaviours known as the fed state. A major feature of the fed state is a little understood motor pattern known as segmentation, which is essential for digestion and nutrient absorption. Segmentation manifests as rhythmic local constrictions that do not propagate along the intestine. In guinea-pig jejunum in vitro segmentation constrictions occur in short bursts together with other motor patterns in episodes of activity lasting 40-60 s and separated by quiescent episodes lasting 40-200 s. This activity is induced by luminal nutrients and abolished by blocking activity in the enteric nervous system (ENS). We investigated the enteric circuits that regulate segmentation focusing on a central feature of the ENS: a recurrent excitatory network of intrinsic sensory neurons (ISNs) which are characterized by prolonged after-hyperpolarizing potentials (AHPs) following their action potentials. We first examined the effects of depressing AHPs with blockers of the underlying channels (TRAM-34 and clotrimazole) on motor patterns induced in guinea-pig jejunum, in vitro, by luminal decanoic acid. Contractile episode durations increased markedly, but the frequency and number of constrictions within segmenting bursts and quiescent period durations were unaffected. We used these observations to develop a computational model of activity in ISNs, excitatory and inhibitory motor neurons and the muscle. The model predicted that: i) feedback to ISNs from contractions in the circular muscle is required to produce alternating activity and quiescence with the right durations; ii) transmission from ISNs to excitatory motor neurons is via fast excitatory synaptic potentials (EPSPs) and to inhibitory motor neurons via slow EPSPs. We conclude that two rhythm generators regulate segmentation: one drives contractions within segmentation bursts, the other the occurrence of bursts. The latter depends on AHPs in ISNs and feedback to these neurons from contraction of the circular muscle. PMID:21573176

Chambers, Jordan D; Bornstein, Joel C; Thomas, Evan A

2011-01-01

378

Coupling of a signal response domain in I kappa B alpha to multiple pathways for NF-kappa B activation.  

PubMed Central

The eukaryotic transcription factor NF-kappa B plays a central role in the induced expression of human immunodeficiency virus type 1 and in many aspects of the genetic program mediating normal T-cell activation and growth. The nuclear activity of NF-kappa B is tightly regulated from the cytoplasmic compartment by an inhibitory subunit called I kappa B alpha. This cytoplasmic inhibitor is rapidly phosphorylated and degraded in response to a diverse set of NF-kappa B-inducing agents, including T-cell mitogens, proinflammatory cytokines, and viral transactivators such as the Tax protein of human T-cell leukemia virus type 1. To explore these I kappa B alpha-dependent mechanisms for NF-kappa B induction, we identified novel mutants of I kappa B alpha that uncouple its inhibitory and signal-transducing functions in human T lymphocytes. Specifically, removal of the N-terminal 36 amino acids of I kappa B alpha failed to disrupt its ability to form latent complexes with NF-kappa B in the cytoplasm. However, this deletion mutation prevented the induced phosphorylation, degradative loss, and functional release of I kappa B alpha from NF-kappa B in Tax-expressing cells. Alanine substitutions introduced at two serine residues positioned within this N-terminal regulatory region of I kappa B alpha also yielded constitutive repressors that escaped from Tax-induced turnover and that potently inhibited immune activation pathways for NF-kappa B induction, including those initiated from antigen and cytokine receptors. In contrast, introduction of a phosphoserine mimetic at these sites rectified this functional defect, a finding consistent with a causal linkage between the phosphorylation status and proteolytic stability of this cytoplasmic inhibitor. Together, these in vivo studies define a critical signal response domain in I kappa B alpha that coordinately controls the biologic activities of I kappa B alpha and NF-kappa B in response to viral and immune stimuli. PMID:7739562

Brockman, J A; Scherer, D C; McKinsey, T A; Hall, S M; Qi, X; Lee, W Y; Ballard, D W

1995-01-01

379

Identification of multiple cellular uptake pathways of polystyrene nanoparticles and factors affecting the uptake: relevance for drug delivery systems.  

PubMed

Nanoparticles may address challenges by human diseases through improving diagnosis, vaccination and treatment. The uptake mechanism regulates the type of threat a particle poses on the host cells and how a cell responds to it. Hence, understanding the uptake mechanisms and cellular interactions of nanoparticles at the cellular and subcellular level is a prerequisite for their effective biomedical applications. The present study shows the uptake mechanisms of polystyrene nanoparticles and factors affecting their uptake in bone marrow-derived macrophages, 293T kidney epithelial cells and L929 fibroblasts. Labeling with the endocytic marker FM4-64 and transmission electron microscopy studies show that the nanoparticles were internalized rapidly via endocytosis and accumulated in intracellular vesicles. Soon after their internalizations, nanoparticles trafficked to organelles with acidic pH. Analysis of the ultrastructural morphology of the plasma membrane invaginations or extravasations provides clear evidence for the involvement of several uptake routes in parallel to internalize a given type of nanoparticles by mammalian cells, highlighting the complexity of the nanoparticle-cell interactions. Blocking the specific endocytic pathways by different pharmacological inhibitors shows similar outcomes. The potential to take up nanoparticles varies highly among different cell types in a particle sizes-, time- and energy-dependent manner. Furthermore, infection and the activation status of bone marrow-derived macrophages significantly affect the uptake potential of the cells, indicating the need to understand the diseases' pathogenesis to establish effective and rational drug-delivery systems. This study enhances our understanding of the application of nanotechnology in biomedical sciences. PMID:25224362

Firdessa, Rebuma; Oelschlaeger, Tobias A; Moll, Heidrun

2014-01-01

380

Utilization of cyanide as nitrogenous substrate by Pseudomonas fluorescens NCIMB 11764: evidence for multiple pathways of metabolic conversion.  

PubMed Central

The growth of Pseudomonas fluorescens NCIMB 11764 on cyanide as the sole nitrogen source was accomplished by use of a modified fed-batch cultivation procedure. Previous studies showing that cyanide metabolism in this organism is both an oxygen-dependent and an inducible process, with CO2 and ammonia representing conversion products, were confirmed. However, washed cells (40 mg ml-1 [dry weight]) metabolized cyanide at concentrations far exceeding those previously described; 85% of 50 mM KCN was degraded in 6 h. In addition, two other C1 metabolites were detected in incubation mixtures; their identities were confirmed as formamide and formate by 13C nuclear magnetic resonance spectrocopy, high-pressure liquid chromatography, radioisotopic trapping experiments, and other analytical means. The relative yields of all four metabolites (CO2, formamide, formate, and ammonia) were shown to be dependent on the KCN concentration and availability of oxygen; at 0.5 to 10 mM substrate, CO2 was the major C1 product, whereas at 20 and 50 mM substrate, formamide and formate were principally formed. The latter two metabolites also accumulated during prolonged anaerobic incubation, suggesting that P. fluorescens NCIMB 11764 can elaborate several pathways of cyanide conversion. One is formally similar to that proposed previously (R. E. Harris and C. J. Knowles, FEMS Microbiol. Lett. 20:337-341, 1983), involving the oxygen-dependent conversion of cyanide to CO2 and ammonia. The other two, occurring in the presence or absence of oxygen, involve separate reactions to yield, respectively, formate plus ammonia or formamide.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1622281

Kunz, D A; Nagappan, O; Silva-Avalos, J; Delong, G T

1992-01-01